Abstract
The invention relates to a laminar structure (10) providing adaptive thermal insulation, comprising a first layer (22), a second layer (24), at least one cavity (16) provided in between the first layer (22) and the second layer (24), a gas generating agent (18) having an unactivated configuration and an activated configuration, the gas generating agent (18) being adapted to change from the unactivated configuration to the activated configuration, such as to increase a gas pressure inside the cavity (16), in response to an increase in temperature in the cavity (16), the first layer (22), the second layer (24) and the cavity (16) being arranged such that a distance (D) between the first layer (22) and the second layer (24) increases in response to the increase in gas pressure inside the cavity (16).
Claims
1. A laminar structure providing adaptive thermal insulation, comprising: a first layer, a second layer, at least one cavity between the first layer and the second layer, a gas generating agent having an unactivated configuration and an activated configuration, and an envelope enclosing the at least one cavity wherein the envelope includes a dosing aid, the dosing aid extending into the cavity and having a portion to which the gas generating agent is applied, said portion being included in the cavity, wherein the dosing aid is made of a material that is able to absorb or adsorb the gas generating agent in the unactivated configuration of the gas generating agent, wherein the laminar structure is configured to reversibly change, in response to an increase in temperature, a distance between the first layer and the second layer, from a first distance in the unactivated configuration of the gas generating agent to a second distance in the activated configuration of the gas generating agent, and in response to a decrease in temperature, from the second distance in the activated configuration of the gas generating agent to the first distance in the unactivated configuration of the gas generating agent.
2. The laminar structure according to claim 1, wherein the gas generating agent is adapted to generate gas in the cavity in response to temperature in the cavity exceeding a predetermined activation temperature of the gas generating agent.
3. The laminar structure according to claim 1, wherein the second distance between the first layer and the second layer in the activated configuration of the gas generating agent is larger than the first distance between the first layer and the second layer in the unactivated configuration of the gas generating agent by a distance of 1 mm or more.
4. The laminar structure according to claim 1, wherein the envelope is configured such that a volume of the at least one cavity increases in response to the increase in gas pressure inside the at least one cavity.
5. The laminar structure according to claim 1, wherein the envelope is fluid tight.
6. The laminar structure according to claim 1, wherein the envelope is made of a non-stretchable material.
7. The laminar structure according to claim 1, wherein the envelope is made of a temperature resistant material with respect to a range of temperatures in the cavity in the activated configuration.
8. The laminar structure according to claim 1, wherein the envelope is made of at least one envelope piece of a fluid tight material.
9. The laminar structure according to claim 1, wherein the envelope is made of a metal/polymer composite material.
10. The laminar structure according to claim 1, wherein the gas generating agent is in the form of a liquid in the unactivated configuration, the activation temperature of the adaptive thermal insulation laminar structure corresponding to a boiling temperature of the gas generating agent.
11. The laminar structure according to claim 10, wherein the gas generating agent is in the form of a solid in the unactivated configuration, the activation temperature of the adaptive thermal insulation laminar structure corresponding to a sublimation or decomposition temperature of the gas generating agent.
12. The laminar structure according to claim 10, wherein the gas generating agent has an evaporation temperature below 200 C.
13. The laminar structure according to claim 12, wherein the liquid comprises CF.sub.3CF.sub.2C(O)CF(CF.sub.3).sub.2.
14. The laminar structure according to claim 1, wherein the gas generating agent is in the form of a liquid, a gel or a solid in the unactivated configuration, the activation temperature of the adaptive thermal insulation laminar structure being a temperature which corresponds to the activation energy of a chemical reaction leading to release of at least one gaseous compound from the gas generating agent.
15. The laminar structure according to claim 1, wherein the dosing aid is smaller than the cavity in the unactivated configuration of the gas generating agent.
16. The laminar structure according to claim 1, wherein the dosing aid is made of a material that is able to support the formation of a fluid tight seal when being welded together with the envelope.
17. The laminar structure according to claim 16, wherein the dosing aid is provided as a sheet forming a weldable dosing aid layer.
18. The laminar structure according to claim 1, wherein the envelope includes an intermediate layer separating the cavity into a first subcavity and a second subcavity, the intermediate layer having a first side and a second side.
19. The laminar structure according to claim 18, wherein the intermediate layer is made of a fluid tight material and is configured to support the formation of a fluid tight seal when being welded together with the envelope.
20. The laminar structure according to claim 18, wherein the gas generating agent is applied to the first side, the second side, or the first side and the second side of the intermediate layer.
21. The laminar structure according to claim 1, further comprising an envelope structure formed by at least two of said envelopes bonded together.
22. The laminar structure according to claim 1, further comprising a plurality of cavities, each of the cavities being encased by a respective said envelope, wherein the envelopes are arranged a distance from each other.
23. The laminar structure according to claim 1, wherein the cavity has a lateral dimension of 1 mm or more in the unactivated configuration and a thickness dimension of 2 mm or less.
24. The laminar structure according to claim 1, wherein the cavity has a relative volume increase between 10 and 2000 with respect to the volume of the cavity when in the activated configuration compared to the unactivated configuration.
25. The laminar structure according to claim 8, wherein the envelope is made of at least a first piece and a second piece, said first and second pieces being bonded together in a fluid tight manner.
26. The laminar structure according to claim 12, wherein the evaporation temperature is between 30 C. and 100 C.
27. The laminar structure according to claim 1, wherein the cavity has a lateral dimension of 5 mm or more in the unactivated configuration and a thickness dimension of 2 mm or less.
28. A laminar structure providing adaptive thermal insulation, comprising: a first layer, a second layer, at least one cavity between the first layer and the second layer, a gas generating agent having an unactivated configuration and an activated configuration, and an envelope enclosing the at least one cavity wherein the envelope includes a dosing aid, the dosing aid extending into the cavity and having a portion to which the gas generating agent is applied, said portion being included in the cavity, wherein the dosing aid is made of a material that is able to support the formation of a fluid tight seal when being welded together with the envelope, wherein the laminar structure is configured to reversibly change, in response to an increase in temperature, a distance between the first layer and the second layer, from a first distance in the unactivated configuration of the gas generating agent to a second distance in the activated configuration of the gas generating agent, and in response to a decrease in temperature, from the second distance in the activated configuration of the gas generating agent to the first distance in the unactivated configuration of the gas generating agent.
29. The laminar structure according to claim 28, wherein the dosing aid is provided as a sheet forming a weldable dosing aid layer.
30. The laminar structure according to claim 28, wherein the gas generating agent is adapted to generate gas in the cavity in response to temperature in the cavity exceeding a predetermined activation temperature of the gas generating agent.
31. The laminar structure according to claim 28, wherein the second distance between the first layer and the second layer in the activated configuration of the gas generating agent is larger than the first distance between the first layer and the second layer in the unactivated configuration of the gas generating agent by a distance of 1 mm or more.
32. The laminar structure according to claim 28, wherein the envelope is configured such that a volume of the at least one cavity increases in response to the increase in gas pressure inside the at least one cavity.
33. The laminar structure according to claim 28, wherein the gas generating agent is in the form of a liquid in the unactivated configuration, the activation temperature of the adaptive thermal insulation laminar structure corresponding to a boiling temperature of the gas generating agent.
34. The laminar structure according to claim 28, wherein the gas generating agent is in the form of a liquid, a gel or a solid in the unactivated configuration, the activation temperature of the adaptive thermal insulation laminar structure being a temperature which corresponds to the activation energy of a chemical reaction leading to release of at least one gaseous compound from the gas generating agent.
35. The laminar structure according to claim 28, wherein the dosing aid is made of a material that is able to absorb or adsorb the gas generating agent in the unactivated configuration of the gas generating agent.
36. The laminar structure according to claim 28, wherein the envelope includes an intermediate layer separating the cavity into a first subcavity and a second subcavity, the intermediate layer having a first side and a second side.
37. The laminar structure according to claim 28, further comprising an envelope structure formed by at least two of said envelopes bonded together.
38. The laminar structure according to claim 28, further comprising a plurality of cavities, each of the cavities being encased by a respective said envelope, wherein the envelopes are arranged a distance from each other.
39. The laminar structure according to claim 28, wherein the cavity has a lateral dimension of 1 mm or more in the unactivated configuration and a thickness dimension of 2 mm or less.
40. The laminar structure according to claim 28, wherein the cavity has a relative volume increase between 10 and 2000 with respect to the volume of the cavity when in the activated configuration compared to the unactivated configuration.
41. The laminar structure according to claim 28, wherein the envelope is made of a temperature resistant material with respect to a range of temperatures in the cavity in the activated configuration.
Description
(1) Exemplary embodiments of the invention will be described in greater detail below taking reference to the accompanying drawings which show embodiments.
(2) FIG. 1a shows a simplified and schematic cross-sectional view of a layer used to form an envelope in an embodiment;
(3) FIG. 1b shows a simplified and schematic cross-sectional view of a further layer used to form an envelope;
(4) FIGS. 2a-2c show a way how to manufacture envelopes;
(5) FIG. 2d shows a plurality of single envelopes;
(6) FIGS. 2e-2g show different embodiments of a sheet layer structure including a plurality of interconnected single envelopes;
(7) FIG. 3a shows a simplified and schematic cross-sectional view of an envelope enclosing a cavity which includes a gas generating agent, according to an embodiment, wherein the envelope laminate layers are welded to each other such as to form the envelope;
(8) FIG. 3b shows a simplified and schematic cross-sectional view of an envelope enclosing a cavity, according to a further embodiment which includes a gas generating agent applied on a dosing aid;
(9) FIG. 3c shows a simplified and schematic cross-sectional view of an envelope enclosing a cavity, according to a further embodiment which includes a gas generating agent applied on a weldable dosing aid layer;
(10) FIG. 3d shows a simplified and schematic cross-sectional view of an envelope, according to a further embodiment, the envelope enclosing two cavities each including a gas generating agent;
(11) FIG. 4a shows a schematic arrangement of two identical envelopes, according to a further embodiment, bonded together one on top of the other;
(12) FIG. 4b shows a further schematic arrangement of two envelopes of different shape, according to a further embodiment, bonded together one on top of the other;
(13) FIG. 4c shows a further schematic arrangement of two envelopes, according to a further embodiment, bonded together at one of their lateral ends,
(14) FIG. 5a shows a simplified and schematic cross-sectional view of an envelope, according to a further embodiment, in an unactivated condition;
(15) FIG. 5b shows a simplified and schematic cross-sectional view of an envelope, according to a further embodiment, in an activated condition;
(16) FIG. 6a shows a simplified and schematic cross-sectional view of a laminar structure, according to an embodiment, formed with a plurality of envelopes positioned in between a first layer and a second layer in an unactivated condition;
(17) FIG. 6b shows a simplified and schematic cross-sectional view of the laminar structure of the embodiment shown in FIG. 5a, in an activated condition;
(18) FIG. 7a shows a simplified and schematic cross-sectional view of a laminar structure, according to a further embodiment, with a plurality of envelopes positioned in between a first layer and a second layer, in an unactivated condition;
(19) FIG. 7b shows a simplified and schematic cross-sectional view of a laminar structure, according to a further embodiment, with a plurality of envelopes positioned in between a first layer and a second layer, in an unactivated condition;
(20) FIG. 7c shows a simplified and schematic cross-sectional view a of laminar structure, according to a further embodiment, with a plurality of envelopes positioned in between a first layer and a second layer, in an unactivated condition;
(21) FIG. 7d shows a simplified and schematic cross-sectional view of a laminar structure, according to a further embodiment, with a plurality of envelopes positioned in between a first layer and a second layer, in an unactivated condition;
(22) FIG. 7e shows a simplified and schematic cross-sectional view of a laminar structure, according to a further embodiment, with a plurality of envelopes in the form of a mesh of envelopes positioned in between a first layer and a second layer, in an unactivated condition;
(23) FIG. 7f shows a simplified and schematic cross-sectional view of a laminar structure, according to a further embodiment, with a plurality of envelopes positioned in between a first layer and a second layer and an additional functional membrane laminated onto one of the first and second layers, in an unactivated condition;
(24) FIG. 8a shows a simplified and schematic cross-sectional view of a fabric including a laminar structure as shown in FIG. 7a;
(25) FIGS. 8b to 8g show other possible configurations of fabrics including the laminar structure providing adaptive thermal insulation according to the invention;
(26) FIG. 9 shows a fire fighter's jacket including a fabric as shown in FIG. 8a;
(27) FIG. 10 shows a schematic sketch of an apparatus to measure increase in distance between the first layer and the second layer when the laminar structure is being brought from the unactivated condition into the activated condition;
(28) FIG. 11 shows a schematic sketch of a laminar structure test piece for measuring the increase in distance between the first layer and the second layer when the laminar structure is being brought from the unactivated condition into the activated condition.
(29) FIG. 12 shows the result of a functionality test for a laminar structure configured to reversibly undergo a plurality of activation/deactivation cycles.
(30) In all Figs. components of respective embodiments being identical or having corresponding functions are denoted by the same reference numerals, respectively. In the following description such components are described only with respect to the first one of the embodiments comprising such components. It is to be understood that the same description applies in respective following embodiments where the same component is included and denoted by the same reference numeral. Unless anything is stated to the contrary, it is generally referred to the corresponding description of that component in the respective earlier embodiment.
(31) FIG. 1a shows a simplified and schematic cross-sectional view of a layer 8 according to an embodiment. Such layer 8 may be used to prepare an envelope. The layer 8 is a laminate comprising a cover layer 8a, a fluid tight layer 8b and a sealing layer 8c. In one example the layer 8 made of an aluminum/plastics composite material comprising a polyethylene terephtalate (PET)-cover layer 8a, an aluminium (Al)-fluid tight layer 8b and a polyethylene (PE)-sealing layer 8c. In order to provide sufficient fluid tightness, a reasonable thickness range for the Al-layer 8b is between 4 m and 25 m. In the example shown the Al-layer 8b has a thickness of at least 12 m. The PE-layer 8c is used as sealing layer by which adjacent laminate layers 8 can be bonded together fluid tightly, in order to create the envelope. The thickness of the PE-layer 8c can be between 20 m and 60 m. A preferable thickness is about 40 m. The PET-layer 8a may be used as a cover layer to provide for desired characteristics of the outer surface of the envelope. In the example a 12 m thick PET-layer 8a is used. The laminate layer 8 as described may be obtained by the company Kobusch-Sengewald GmbH, Germany.
(32) An alternative layer 8 for forming the envelope is shown in FIG. 1b. This layer 8 also is a laminate including a cover layer 8a made of PE with a thickness of 40 m, an Al layer 8b with a thickness of at least 12 m, and a PE sealing layer 8c with a thickness of 40 m. In this embodiment the cover layer 8a is made of the same material as the sealing layer 8c. The cover layer 8a may be used as an additional sealing layer.
(33) FIG. 3a shows a simplified and schematic cross-sectional view of an envelope (generally designated as 20) enclosing a cavity 16 which includes a gas generating agent (generally designated as 18). In FIG. 3a, as well as in each of FIGS. 3b, 3c, 3d, 4a, 4b,4c, the envelope 20 is shown in an unactivated configuration of the gas generating agent 18, and hence the envelope 20 has an uninflated, essentially flat shape, also referred to as the unactivated condition. In a flat configuration as shown in FIGS. 3a to 3d and FIGS. 4a to 4c, the envelope 20 has a dimension in thickness direction being significantly smaller than the dimensions of the envelope 20 directions orthogonal to the thickness direction, i.e. in lateral directions. Dimension of the envelope 20 in thickness direction is designated by d in FIGS. 3a-4c. Dimension of the envelope 20 in lateral direction is designated by A0 in FIGS. 3a to 4c. Here, A0 designates the length from one end of the weld to the end of the opposite weld of the envelope 20. In embodiments with a generally round or quadrangular shape of the envelope, dimensions A0 of the envelope may be substantially equal for all lateral directions. In other embodiments of the envelope with a generally elongate shape, dimension A0 in a width direction may be smaller than dimension A0 in a length direction.
(34) In an embodiment the envelope 20 is made of two envelope layers 12, 14. Envelope layers 12, 14 may each have a configuration as the layers 8 shown in FIG. 1a or 1b. Particularly, although not explicitly shown, the envelope layers 12, 14 may be each made up of three layers, corresponding to the layers 8 depicted in FIG. 1a or FIG. 1b. The envelope layer 12 forms an upper part of the envelope 20, such upper part enclosing an upper part of cavity 16. The envelope layer 14 forms a lower part of the envelope 20, such lower part enclosing a lower part of cavity 16. In the embodiment shown, the envelope layer 12 and the envelope layer 14 have an identical configuration, e.g the configuration of the layer 8 shown in FIG. 1a. The envelope 20 has an innermost sealing layer, an intermediate fluid tight layer, and an outside cover layer.
(35) Alternatively, the envelope 20 may be made up of two envelope layers 12, 14 configured from a layer 8 as depicted in FIG. 1b, or may be made up of one envelope layer 12 configured from a layer 8 as depicted in FIG. 1a and one envelope layer 14 configured from a layer 8 as depicted in FIG. 1b. Alternative materials, in particular monolayers or laminate layers of more or less complicated configuration, may be used for making the envelope 20, as outlined above, given the materials themselves are fluid tight and bonded together fluid tightly such that a fluid tight envelope 20 is produced. In one embodiment the envelope layers may made of a fluid tight single layer (monolayer). Said layer might be formed to the envelope by welding or gluing.
(36) The envelope 20 encloses cavity 16 which is filled with gas generating agent 18. Gas generating agent 18 is chosen to be a liquid having a suitable equilibrium vapor pressure at room temperature. Room temperature is considered to define an unactivated configuration of gas generating agent 18. In the unactivated configuration of the gas generating agent 18 shown in FIG. 3a, gas generating agent 18 is substantially in its liquid phase designated by 18. The envelope 20 provides a substantially fluid tight enclosure of cavity 16, and hence cavity 16 contains sufficient amount of gas generating agent 18, and the remaining volume of cavity 16 is filled with gas, in particular with a rest amount of air or other gas having been enclosed in cavity 16 at the time gas generating agent 18 was filled in. In the example disclosed, gas generating agent 18 is a fluid having the chemical formula CF.sub.3CF.sub.2C(O)CF(CF.sub.3).sub.2. Such fluid is typically used for extinguishing fires and is commercially available under the trade name Novec 1230 Fire extinguishing fluid from 3M. Other fluids may be used for the gas generating agent, as set out above.
(37) A first method for producing an envelope 20 as shown in FIG. 3a is as follows:
(38) First Sealing Step:
(39) Two envelope layers 12, 14 made from a material according to FIG. 1a or 1b are put on top of each other, such that their respective sealing layers face each other. For forming a quadrangular envelope 20 a hot bar (sealing width: 2 mm) is brought into contact with the envelope layers 12, 14 such as to bring the sealing layers into contact and to weld the sealing layers together. This procedure is done for three of four sides of the quadrangular envelope 20. Thus an envelope 20 with one side open is formed.
(40) Filling Step:
(41) The envelope 20 is put onto a precision scale and the gas generating agent 18 is filled into the envelope, e.g using a syringe needle. The amount of gas generating agent to be filled in is controlled by the scale.
(42) As an Example:
(43) A quantity of 0.07 g gas generating agent 18 will be filled into the envelope 20, in case the envelope 20 has the following specification: the envelope 20 is formed from two envelope layers 12, 14 made up of PET/Al/PE as described above, outer size of the envelope 20 is 20 mm length and 20 mm width (corresponding to an inner size of the cavity of 16 mm length and 16 mm width), and gas generating agent 18 is selected as Novec 1230.
(44) Second Sealing Step:
(45) After the filling step is finished the open side of the envelope 20 is closed by a fourth 2 mm sealing line. The envelope 20 is then cut precisely along the sealing line.
(46) Correctness of the filling quantity for envelopes produced as outlined above can be measured as follows:
(47) A predetermined quantity of envelopes 20 (e.g. 10 envelopes) is produced according to the first sealing step, each of these envelopes 20 is marked and weighed individually on a 4 digit scale (e.g. Satorius BP121S). A predetermined quantity of gas generating agent 18 in the form of a liquid is injected through a pipe from a gravity feed reservoir, including a time-triggered valve, through a syringe needle into the interior of the envelope. A predetermined time for valve opening is ensured by an adjustable electrical timer. Each envelope 20 is closed immediately by the second sealing step. Each of the filled envelopes 20 is weighed, and the weight of the empty envelope 20 (measured before filling) is subtracted. A maximum deviation of plus/minus 10% from the mean value of the sample set should be achievable.
(48) A second method for producing an envelope 20 according to FIG. 3a is shown in FIGS. 2a to 2d, and is as follows:
(49) First Step (FIG. 2a):
(50) An elongate sheet, e.g. sheet being 65 mm wide and 1.3 m long, made from a laminate material 8 according FIG. 1a is used. Alternatively, a sheet of different size and/or made from another laminate material, e.g. made from a laminate material 8 as shown in FIG. 1b, may be used. The sheet is folded along its long side in such a way that the cover layer 8a of the laminate 8 (see FIG. 1a or FIG. 1b) is located outside, and the sealing layer 8c is located inside. Thereby, an upper envelope layer 12 and a lower envelope layer 14 are formed in such a way that the sealing layers of the envelope layers 12, 14 are facing each other. In this way a pre-envelope 101 is created. The pre-envelope 101 has a width of 32.5 mm and a length of 1.3 m. The pre-envelope 101 is closed at its one long side 102 and is open along its opposite long side 103. Both short sides 104 and 105 of the pre-envelope 101 are open.
(51) Second Step (FIG. 2b):
(52) A rotating ultrasonic welding wheel (e.g. 5 mm wide) is brought into contact with the pre-envelope 101 at the open long side 103, such as to bring the two sealing layers of the envelope layers 12, 14 into contact with each other. The sealing layers are welded together continuously along a sealing line 106 extending parallel to the open long side 103 of the pre-envelope 101. Thereby the long side 103 is closed and the pre-envelope 101 has a tubular shape with two open short sides 104, 105. A hot sealing bar (sealing width: 2 mm) is brought into contact with the pre-envelope 101 at one of the shorter sides 105, such as to bring the sealing layers into contact with each other. The sealing layers are welded together along a sealing line 107 extending parallel to the shorter side 105 such as to close the pre-envelope 101 at the shorter side 105. The pre-envelope 101 then has a shape of a tube with one end closed.
(53) Then, holding open short side 104 higher than closed short side 105, gas generating agent 18 is filled into the open tubular pre-envelope 101 via the open short side 104. As an example, for a pre-envelope 101 as described and forming a cavity with inner size of 23 mm in width and 1 m in length, the pre-envelope 101 being made of a laminate layer 8 made up of PET/Al/PE, as described above and shown in FIG. 1a, and for a gas generating agent 18 being a liquid known as Novec 1230, as described above, a quantity of 4 ml of gas generating agent 18 is filled into the pre-envelope 101.
(54) Third Step (FIG. 2c)
(55) The pre-envelope 101 is held with its open short side 104 facing upwards, and is held in an up-right position, such that the gas generating agent 18 filled in the cavity concentrates at the closed shorter side 105 of the pre-envelope 101. Starting from the closed shorter side 105, the pre-envelope 101 is brought into intimate contact with a second rotating ultrasonic welding wheel 110. Welding wheel 110 is part of an ultrasonic welding machine having a pair of welding wheels 110, 111. The welding wheel 110 has a circumferential face 112 formed with a plurality of circumferential seal contours 114A, 114B, . . . . Each of the seal contours 114A, 114B, . . . has a shape corresponding to the shape of the sealing line of the envelopes 20A, 20B, . . . to be produced (FIG. 2d). In this configuration welding wheel 111 has a planar circumferential surface.
(56) The pre-envelope 101 is transported through the pair of welding wheels 110, 111 starting with its short closed side 105, see arrow B in FIG. 2c indicating the direction of movement of the pre-envelope 101. In this way the welding wheel 110 first contacts first the closed short side 105 of the pre-envelope 101 and finally contacts the open short side 104 of pre-envelope 101.
(57) When the welding wheel 110 contacts the pre-envelope 101, the gas generating agent 18 is pushed away by the rotating ultrasonic welding wheels 110, 111 in areas where one of the sealing contours 114A, 114B, comes into contact with the pre-envelope 101, since in such areas the sealing layers are brought into contact with each other and are welded together. In this way, a closed sealing contour 116A defining the sealing portions of the final envelope 20A (FIG. 2d) is formed in the pre-envelope 101.
(58) As the pre-envelope 101 travels through the gap between the rotating welding wheels 110, 111 a plurality of consecutive sealing contours 116A, 116B, . . . are formed in the pre-envelope 101. Each sealing contour 116A, 116B, . . . encloses a respective cavity 16A, 16B, . . . filled by a predetermined amount of gas generating agent 18.
(59) It has been found that, following the procedure described above, each cavity 16A, 16B, . . . formed in pre-envelope 101 can be filled by the approx. same predetermined amount of gas generating agent 18. Particularly good reproducible results can be obtained by using an ultrasonic welding tool, e.g. in the form of a pair of ultrasonic welding wheels 110, 111, to produce the sealing contours 116A, 116B, . . . in the pre-envelope 101.
(60) In one example having dimensions as outlined above 40 filled sealing contours 116A, 116B, . . . , each having outer dimensions of 20 mm width and 23 mm length and a cavity size of 16 mm width and 18 mm length, can be created.
(61) Fourth Step (FIG. 2d):
(62) Finally, the final pre-envelope 101 having sealing contours 116A, 116B, . . . formed therein, is cut, e.g. using a hand operated or automated standard dye cut machine with a cutting dye having the shape of the outer dimensions of the sealing contours 116A, 116B, . . . . In this way individual envelopes 20A, 20B, . . . , as shown in FIG. 2d, are produced.
(63) It is even conceivable to omit the fourth step, i.e. the last cutting step. Then instead of a plurality of single envelopes 20, a sandwich type laminate sheet 100 (see FIG. 2e), 200 (see FIG. 2f) including an array of a plurality of envelopes 20A, 20B, 20C, . . . is provided. In such sheet layer structure 100, 200, the envelopes 20A, 20B, 20C, . . . may be aligned along a single line, as indicated for sheet layer structure 100 of FIG. 2e which is produced from a pre-envelope 101 according to FIGS. 2a to 2c. It also possible to use a planar pre-envelope 201 of rectangular or quadrangular shape, and to produce a sheet layer structure 200 including plurality of lines of envelopes 20A1, 20B1, 20C1, . . . , 20A2, 20B2, 20C2, . . . , 20A3, 20B3, 20C3, . . . , such lines of envelopes being arranged next to each other and extending parallel to each other, as shown in FIG. 2f. The material of the sheet layer structure 100 or sheet layer structure 200 outside the envelopes forms a connecting structure 109, 209 for the envelopes 20A1, 20B1, 20C1, . . . , 20A2, 20B2, 20C2, . . . , 20A3, 20B3, 20B3, . . . .
(64) In an further embodiment, shown in FIG. 2g, a mesh 210 of envelopes 20A1, 20B1, 20C1, . . . , 20A2, 20B2, 20C2, . . . , 20A3, 20B3, 20C3, . . . can be produced by cutting non-used portions 212 of the sheet material forming the envelope layers 12, 14 in between adjacent envelopes in such a way that each envelope is still connected to its adjacent envelopes by an interconnecting web 219 formed by the sheet material 12, 14.
(65) Correctness of the filling quantity for envelopes produced according to the second method above can be measured as follows:
(66) A predetermined quantity of envelopes 20 (e.g. 10 envelopes) are produced according to the first to fourth sealing/filling steps above, each of these envelopes 20 is marked and weighed individually on a 4 digit scale (e.g. Satorius BP121S). Each of the envelopes 20 is put on a hot plate with a temperature well above the activation temperate of the gas generating agent 18 to ensure that each of the envelopes 20 will burst and release the gaseous gas generating agent 18 completely. The empty envelopes are weighed individually on a 4 digit scale. The weight loss of each envelope is calculated. In case of humidity pick-up of the envelope material, the envelopes must be conditioned for at least 1 h in the same environment, ideally at 23 C. and 65% relative humidity.
(67) Fluid tightness of the envelope can be measured according to one of the following methods:
(68) Method 1 for Measurement of the Fluid Tightness of the Envelopes:
(69) Each envelope 20 is marked individually. Each envelope 20 is weighed on a 4 digit scale (e.g. Satorius BP121S). The envelopes 20 are stored under predetermined environmental conditions (20 C., 65% relative humidity). The weighing procedure described is repeated after 1 month of storage. This procedure is continued for at least 6 months. The weight loss after 6 months should be less than 20%, better 10%, ideally less than 1% of the filling weight. Additionally, functionality of each envelope 20 is checked after 6 months on a hot plate or in a water bath. The envelope 20 must show thickness increase when subjected to temperature above activation temperature.
(70) FIG. 3b shows an envelope 20 enclosing a cavity 16 according to a further embodiment. The envelope 20 shown in FIG. 3b includes a gas generating agent 18 applied on a dosing aid 19. The dosing aid 19 may be made of any material that is able to absorb gas generating agent 18, e.g. an absorbent paper material, a woven or non-woven textile material, or a sponge-like material. In FIG. 3b a blotting paper is used as the dosing aid 19. The dosing aid 19 is soaked with a predefined amount of gas generating agent 18, and then is inserted into the cavity 16. This can be done in a way similar to the first method described above. As an alternative to the procedure described above, the dosing aid 19 may be provided with the gas generating agent 18 in a first step, and then the dosing aid 19 may be arranged in between the first and second envelope layers 12, 14, before the first and second envelope layers are bonded together. Gas generating agent 18, once activated, will be released from dosing aid 19 and inflate cavity 16.
(71) In the embodiment of FIG. 3b the dosing aid 19 has smaller lateral dimension than the cavity 16 has, such that the dosing aid 19 does not interfere with the bonding (e.g. along sealing lines) of the first and second envelope layers 12, 14.
(72) FIG. 3c shows an envelope 20 enclosing a cavity 16 according to a further embodiment. Also in this embodiment, the envelope 20 includes a gas generating agent 18 applied on a dosing aid 19. In this embodiment the dosing aid 19 is made of a material that does not interfere with the bonding process used to bond the envelope layers 12, 14 together, or may even be made of material that does support such bonding process as a sealing layer. This allows the dosing aid 19 to be applied in a sandwich type arrangement between the first and second envelope layers 12, 14 before these are bonded together. The dosing aid 19 may even cover the sealing areas where the first and second envelope layers 12, 14 are to be bonded together. Hence the dosing aid 19 may have a sheet like configuration and be used in the form of a dosing aid layer 19 interposed in between the first and second envelope layers 12, 14 and covering the whole sealing area of the first and second envelope layers 12, 14. The first and second envelope layers 12, 14 are bonded together along the sealing areas, e.g. by welding, with the dosing aid 19 interposed.
(73) Given the gas generating agent 18 does not interfere with the bonding of the first and second envelope layers 12, 14, gas generating agent 18 may be applied to the dosing aid 19 as a whole. To restrict areas where gas generating agent is applied to the dosing aid in a sealing portion, the gas generating agent 18 may be applied in the form of discrete stripes onto the dosing aid 19. Distance between the stripes can then be selected such that each envelope is crossed by one stripe of gas generating agent. It will generally be more advantageous to apply the gas generating agent 18 only at those portions of the dosing aid 19 which will be inside the cavity 16, i.e. which will be fully enclosed by sealing areas where the first and second envelope layers 12, 14 are bonded together. In this way, the desired predetermined amount of gas generating agent 18 for proper activation and inflating of the envelope 20 can be adjusted more precisely. E.g. the gas generating agent 18 may be applied to the dosing aid 19 in an array of a plurality of discrete spots or areas, all of which are fully enclosed in a respective cavity 16.
(74) In an embodiment where the first and second envelope layers 12, 14 are bonded together by welding having the dosing aid in between, the dosing aid 19 may be made of a textile structure like polypropylene non-woven; or may be made of a porous material like expanded polyethylene (ePE) or expanded polypropylene (ePP). Each of these materials allows welding of the first envelope layer 12 to the second envelope layer 14 with a layer of that material interposed in between.
(75) In a further embodiment, the first envelope layer 12 and/or the second envelope layer 14 may provide the function of the dosing aid 19. This can be achieved by forming the innermost layers of the first envelope layer 12 and/or the second envelope layer 14, which come into contact when welding the first envelope layer 12 to the second envelope layer 14, from a suitable material, e.g. the materials mentioned before.
(76) In the embodiment shown in FIG. 3c the dosing aid 19 is interposed in the form of a further layer in between the first and second envelope layers 12, 14 in such a way that two sub-cavities 16a and 16b are formed. Subcavity 16a is enclosed by upper envelope layer 12 and dosing aid layer 19, subcavity 16b is enclosed by lower envelope layer 14 and dosing aid layer 19. Gas generating agent 18, once activated, will be released from dosing aid 19 and inflate subcavities 16a and 16b. As dosing aid 19 is not fluid tight with respect to gas generating agent 18, at least not while the gas generating agent 18 is in the activated configuration (gaseous configuration), some exchange of gas generating agent 18 between subcavities 16a and 16b remains possible. This embodiment has the advantage that the convection of the gas generating 18 agent within the envelope 20 is limited.
(77) FIG. 3d shows another envelope 20 according to a further embodiment. The envelope 20 of FIG. 3d has first and second envelope layers 12, 14 and an intermediate layer 21. In the embodiment shown, the intermediate layer 21 has a configuration according to the layer 8 in FIG. 1b, but may have other configuration in other embodiments. The intermediate layer 21 is interposed between layer 12 and layer 14 in a sandwich type arrangement. Similar to the embodiment of FIG. 3c, this arrangement provides for two subcavities 16a and 16b being formed. However, different from the embodiment of FIG. 3c, the gas generating agent 18 is provided separately as first gas generating agent 18a for subcavity 16a and as a second gas generating agent 18b for second subcavity 16b. In a further embodiment (not shown in the figures) the first gas generating agent 18a may be provided by a first dosing aid 19a, similar to the embodiment of FIG. 3b. The second gas generating agent 18b may be provided by second dosing aid 19b, also similar to the embodiment of FIG. 3b.
(78) Further, the intermediate layer 21 is made of essentially fluid tight material with respect to gas generating agent 18a, 18b in the unactivated configuration as well as with respect to gas generating agent 18a, 18b in the activated configuration. Intermediate layer 21 is also made of material that provides a fluid tight bonding between first and second envelope layers 12, 14, as described above. A suitable combination of materials in the embodiment of FIG. 3d is: First envelope layer 12: PET/Al/PE (see FIG. 1a); intermediate layer 21: PE/Al/PE (see FIG. 1b); second envelope layer 14: PET/Al/PE (see FIG. 1a).
(79) It is also possible to use an intermediate layer 21 being coated with a dosing aid layer 19a and a dosing aid layer 19b on both of its sides, such coating layers 19a, 19b acting as a dosing aid for the first and second subcavities 16a, 16b, respectively.
(80) In the embodiment of FIG. 3d, the size/volume of subcavities 16a and 16b, and correspondingly the amount of gas generating agent 18a, 18b to be filled in the subcavities 16a, 16b can be adjusted as desired. It is also possible to use different gas generating agents 18a and 18b in subcavities 16a and 16b, respectively. This can be important, as regularly one of the subcavities 16a, 16b will be arranged closer to a source of heat than the other subcavity. Thus, the envelope 20 of FIG. 3d can be designed in such a way that the gas generating agent 18a or 18b in the subcavity 16a or 16b which is arranged closer to the source of heat has a higher activation temperature than the other subcavity. Further, provision of two independent subcavities provides for redundance in the sense that the adaptive insulation system still works in case one of the subcavities is broken.
(81) FIG. 3d further indicates that the thickness d of envelope 20 will be determined by the sum of two distances da (thickness of first subcavity 16a), and db (thickness of second subcavity 16b). Both da and db will increase in case gas generating agents 18a, 18b will change from the unactivated configuration to the activated configuration, respectively. Increase in distance between the first layer and the second layer of the laminar structure according to the invention after activation of the gas generating agents 18a and 18b from D0 to D1 (see FIGS. 6a and 6b) will be substantially identical to the increase in thickness d of the envelope 20, and hence given by increase in thickness da of the first subcavity 16a plus the increase in thickness db of second subcavity 16b.
(82) Besides facilitating the accurate dosing of gas generating agent 18, dosing aid 19, as shown in FIG. 3c, provides the advantage that it can be applied in a sandwich type configuration as an intermediate sheet in between the first and second envelope layers 12 and 14. This allows for simplified manufacture of the envelopes 20. It is possible to manufacture a plurality of envelopes 20 using only one sheet of envelope layer 12, one sheet of dosing aid layer 19 and one sheet of envelope layer 14. Using a dosing aid layer 19 as described is particularly helpful for the manufacture of a planar sheet of envelopes 200, as shown in FIG. 2f, or of a mesh of envelopes 210, as shown in FIG. 2g.
(83) FIGS. 4a, 4b and 4c show arrangements of two envelopes 20a and 20b which are bonded together via a bond 23a to form an envelope structure. Such arrangement has in use very similar properties to the embodiment shown in FIG. 3d. Each of the envelopes 20a, 20b encloses a respective cavity 16a, 16b. First cavity 16a includes a first dosing aid 19a provided with first gas generating agent 18a in a manner similar to the embodiment of FIG. 3b. Second cavity 16b includes a second dosing aid 19b provided with second gas generating agent 18b in a manner similar to the embodiment of FIG. 3b. Alternatively to the use of a dosing aid 19a, 19b according to the embodiment of FIG. 3b, gas generating agents 18a and 18b may be provided without using a dosing aid, similar to the embodiment of FIG. 3a, or using a dosing aid layer 19a, 19b, similar to the embodiment of FIG. 3c. Each envelope 20a, 20b is essentially fluid tight. As to the options for activation of first and second gas generating agents 18a, 18b, the same applies as outlined above with respect to the embodiment of FIG. 3d.
(84) In the embodiment of FIG. 4a both envelopes 20a, 20b have an essentially identical size. FIG. 4b shows a further embodiment which is identical to the embodiment of FIG. 4a except that the envelope 20a is smaller than the envelope 20b.
(85) In the embodiments of FIGS. 4a and 4b the envelopes 20a, 20b are bonded together by a bond located in a central portion of the envelopes 20a, 20b. Hence, similar to the embodiment of FIG. 3d thickness d of the envelope structure is determined by the sum of two distances da (thickness of first cavity 16a) and db (thickness of second cavity 16b). Increase in distance D between the first layer and the second layer after activation of the gas generating agents 18a and 18b will be substantially identical to the increase in thickness d of the envelope structure, and hence given by increase in thickness da of the first cavity 16a plus the increase in thickness db of second cavity 16b.
(86) Bonding of the envelopes 20a and 20b can be effected by suitable adhesives, by welding or by stitching (in the case of stitching proper measures should be taken to maintain fluid tightness).
(87) FIG. 4c shows a further schematic arrangement of two envelopes 20a, 20b bonded together to form an envelope structure. In this embodiment, envelopes 20a, 20b are bonded together by a bond 23b located at one of the lateral ends of envelopes 20a, 20b. As can be seen in FIG. 4c, by such lateral arrangement of bond 23b an angle larger than zero is formed in between the lateral plane of the first envelope 20a and the lateral plane of second envelope 20b. The lateral plane of an envelope 20a, 20b is defined as a plane orthogonal to the thickness direction of the envelope, respectively.
(88) With a lateral bond 23b as shown in FIG. 4c, thickness d of the envelope structure is not determined by the sum of the thickness da of first cavity 16a plus the thickness db of second cavity 16b, wherein da and db are measured orthogonal to the planar planes of cavities 16a, 16b, respectively (as indicated for the embodiments of FIGS. 4a and 4b). Rather, as shown in FIG. 4c, the thickness d of the envelope structure is determined by the thickness db of second cavity 16b plus an effective thickness da of first cavity 16a. Effective thickness da of first cavity is given approximately by daA sin , where A is the lateral dimension of first envelope 20a.
(89) The angle will increase when, after activation of the gas generating agents 18a, 18b, the first and second envelopes 20a, 20b change their condition from the unactivated condition (both envelopes 20a, 20b being essentially flat) to the activated condition (both envelopes 20a, 20b being inflated and thus convex shaped). Thereby the increase in effective thickness da of the first cavity 16a in the activated configuration of gas generating agents 18a, 18b becomes larger than the increase in thickness da of the first cavity 16a measured orthogonal to planar plane of cavity 16a (see FIGS. 4a and 4b). Increase in distance D between the first layer and the second layer of the inventive laminar structure after activation of the gas generating agents 18a and 18b will be substantially identical to the increase in thickness d of the envelope structure, and hence given by increase in effective thickness da of the first cavity 16a plus the increase in thickness db of second cavity 16b.
(90) By increasing the angle when changing from the unactivated condition to the activated condition, the envelope structure of FIG. 4c provides a function similar to a hinge. This is a very efficient way of increasing such distance, in particular in case the envelopes have an essentially flat configuration in the unactivated condition, since in such configuration the lateral dimension A of the envelopes is large, and the angle will increase significantly upon activation. Even more than two envelopes 20a, 20b can be bonded together in this way to provide pronounced hinge-type behaviour in the way of unfolding an accordion, when changing from the unactivated condition to the activated condition.
(91) A consequence of this hinge-type behaviour is that the envelope structure allows for a large increase in distance between a first layer and the second layer in a fabric structure having the envelope structure of FIG. 4c sandwiched in between. Alternatively, to achieve a desired increase in distance between the first layer and the second layer, an envelope structure can be used covering much less area of the fabric than it would be necessary if single envelopes were used, or even if envelope structures as show in FIGS. 4a and 4b were used.
(92) By arranging a plurality of two or even more envelopes 20a, 20b, . . . on top of each other, as just described, very large increase in thickness of the envelope structure as a whole can be achieved, thereby enabling a very pronounced increase in distance between first layer and second layers. The result is a very effective increase in thermal insulating capability as a result of a temperature change. This particularly holds for the embodiment of FIG. 4c providing for a hinge-type effect when changing from the unactivated condition to the activated condition.
(93) Also in the embodiment of FIG. 4c, bonding of the envelopes 20a and 20b can be effected by suitable adhesives, by welding or by stitching (in the case of stitching proper measures should be taken to maintain fluid tightness). A further possibility is to provide the envelopes 20a, 20b in the form of a sheet layer structure 100, 200, 210 of a type as shown in FIGS. 2c, 2d, 2e. Such sheet layer structure may easily be folded to provide an envelope structure of the type shown in FIG. 4c.
(94) The functionality of a laminar structure providing adaptive thermal insulation according to the invention in an activation cycle is demonstrated in FIGS. 5a and 5b. Only a single envelope 20 is used in FIGS. 5a and 5b for demonstration purposes, it be understood that a laminar structure according to the invention may include any number of envelopes 20 or envelope structures, as desired. FIG. 5a shows the envelope 20 in an unactivated condition, as shown in FIG. 3a, with the gas generating agent 18 in the liquid phase (indicated as 18). FIG. 5b shows the envelope 20 in an activated condition, i.e. after the gas generating agent 18 has been evaporated into its gaseous phase (indicated as 18). It can be seen by comparing FIGS. 5a and 5b that the shape of the envelope 20 has changed from a flat shape with only small thickness d0 (corresponding to the distance d0 between the outer surfaces of first laminated layer 12 and second laminated layer 14 in thickness direction of the envelope 20) in the unactivated condition to a concave shape with much larger thickness d1 (corresponding to distance d1 in FIG. 5b). Correspondingly the dimension of the envelope 20 in directions orthogonal to the thickness direction reduces slightly from a dimension A0 in the unactivated condition to a dimension A1 in the activated condition. The first and second laminate layers 12, 14 are made of essentially non-stretchable material which does not significantly elongate in any direction after response to activation of the gas generating agent 18. However, in response to increasing pressure in the cavity 16 upon activation of the gas generating agent 18, the shape of the envelopes 20 changes in such a way that a maximum volume of the cavity 16 has been built.
(95) FIGS. 6a and 6b show an exemplary embodiment of a laminar structure 10 according to the invention.
(96) The embodiment of FIGS. 6a and 6b comprises a plurality of envelopes 20 (as described in detail with respect to FIGS. 3a to 5b above) positioned in between a first layer 22 and a second layer 24. Both the first and second layer 22, 24 may be textile layers. In a possible configuration the textile layers 22, 24 may be connected via stitches 27 in the form of a quilted composite. In this way, pockets 25 are formed by the first and second layers 22, 24. In this embodiment, each of these pockets 25 receives a respective one of the envelopes 20. Other embodiments are conceivable in which each pocket 25 receives more than one envelope 20, or where part of the pockets 25 do not receive any envelope 20. Of course, instead of single envelopes, the pockets 25 may receive an envelope structure. The envelopes 20 are thus fixed by their respective pocket 25 with respect to movement in the length/width plane defined by the layers 22, 24.
(97) In a possible configuration, the first layer 22 may be a textile having flame resistant properties. In one example the first layer 22 is made of 55 g/m.sup.2 spun-laced non-woven of aramid fiber (available as Vilene Fireblocker from the company Freudenberg). The second layer 24 may be a fire resistant textile liner made of 125 g/m.sup.2 aramid viscose FR blend 50/50 woven (available from the company Schueler). Both, the first layer 22 and the second layer 24 may be either a non woven or a woven, depending on the application.
(98) Comparing FIGS. 6a and 6b it is evident that activation of the gas generating agent 18 provides for a volumetric increase (inflation) of the envelopes 20 in the pockets 25. Such inflation of the envelopes 20 induces movement of the first layer 22 and second layer 24 away from each other and increases the distance D between the first layer 22 and the second layer 24 from a first distance D0 to a second distance D1. FIGS. 6a and 6b further show that in case the first layer 22 and/or the second layer 24 have a structure with embossments and depressions, it may be convenient to measure the distances D0, D1 with respect to reference planes of the first and second layers 22, 24 respectively. In the example shown the distances D0, D1 are measured using reference planes touching the most distant points of the first and second layers 22, 24 respectively.
(99) FIGS. 6a and 6b further show that the envelopes 20 are received in the pockets 25 in such a way that gaps remain free in between each two neighbouring envelopes 20. The distance of these gaps is indicated by X. It can be seen that this distance X remains nearly constant or even increases slightly, when the gas generating agent 18 in the envelopes 20 changes from the unactivated configuration to the activated configuration. Further, thermally triggered shrinkage of the laminate structure 10 is advantageously reduced.
(100) FIG. 7a shows a simplified and schematic cross-sectional view of a laminar structure 10 according to a further embodiment. The laminar structure 10 is similar to FIG. 6a with a plurality of envelopes 20 positioned in between a first layer 22 and a second layer 24 in an unactivated condition. In the embodiment of FIG. 7a the envelopes 20 are fixed to layer 22 by means of adhesive spots 29. Such adhesive spots 29 may provide fixation of the envelopes 20 only temporarily for mounting purposes. In such case, typically additional measures for fixing the envelopes 20 in position will be provided, e.g. stitches 27 to form pockets in the type of a quilted composite structure as shown in FIG. 6a.
(101) Alternatively, the adhesive spots 29 may be formed of an adhesive providing durable fixation of the envelopes with respect to either first layer 22 (see FIG. 7a) or second layer 24, or to both of them (see FIG. 7b). In such case, additional stitches 27 are not absolutely necessary.
(102) It is also possible to fix envelope structures of a type as described above at a respective position using suitable adhesive spots 29. As an example, FIG. 7c shows an embodiment with double envelope structures fixed to each other via an adhesive spot 23a, wherein each envelope structure is fixed to the first layer 22 by respective further adhesive spots 29. Alternatively, envelope structures of two or more envelopes 20, respectively, may be formed by connecting the envelopes 20 with each other via adhesive spots 23a and inserting the composite structures into respective pockets 25 without connecting the composite envelope structures with any of the first layer 22 and second layer 24, see FIG. 7d (double envelope structures fixed to each other via adhesive spots 23a, but unfixed with respect to first layer 22 and second layer 24).
(103) In all embodiments shown, the envelopes 20 may be connected with the first layer 22 and/or the second layer 24 via stitches, instead of adhesive spots 29 (not shown in the figures).
(104) FIG. 7e shows a laminar structure 10, according to a further embodiment, with a plurality of envelopes 20 forming a sheet layer structure 210 of envelopes in an unactivated condition. The sheet layer structure 210 is of a mesh type as shown in FIG. 2g and is positioned in between a first layer 22 and a second layer 24. The envelopes 20 are formed as an array of envelopes 20. Stitches 31 can be used to fix the sheet layer 210 of envelopes at the first layer 22 and/or second layer 24. Connection of a plurality of envelopes may be provided by producing an array of envelopes 20 from sheet like laminate layers 12, 14 (and intermediate layer 18, dosing aid 19, if desired), see FIG. 2g, and optionally cutting only unused spaces in between individual envelopes 20 in such a way that the envelopes 20 are connected with each other via remaining webs of material formed by first and second laminate layers 12, 14, see FIG. 2g. Such a mesh 210 of envelopes is breathable.
(105) In FIG. 7e first layer 22 and the second layer 24 are not fixed to each other. Only the sheet layer 210 of envelopes is fixed to the first layer 22, and may optionally be fixed to the second layer 24. The laminar structure 10 in such embodiment provides a relatively loosely coupled structure. Such arrangement facilitates assembly of the laminar structure 10 and provides for flexibility. In case a tighter connection between the first and the second layer 22, 24 is desired it is possible to additionally provide stitches joining the first and second layers 22, 24 with each other. Generally such additional stitches will be provided with larger distances to each such as to form rather large pockets. In a further embodiment it is possible to connect a plurality of envelopes 20 such as to form a chain of envelopes 20 (see e.g. FIG. 2e), and to connect the first layer 22 and the second layer 24 via a plurality of parallel stitches 31 running parallel to each other. The first and second layers 22, 24 thus will form a plurality of channels in between each two adjacent stitches 31. Into such channels a respective chain of envelopes 20 may be introduced.
(106) FIG. 7f shows a laminar structure 10, according to a further embodiment in an unactivated condition. The laminar structure 10 of FIG. 7f is similar to the embodiment shown in FIG. 7a and has an additional functional layer 40 attached to at least the first layer 22 or the second layer 24. In the embodiment of FIG. 7f the functional layer 40 is attached to the second layer 24. The additional functional layer 40 may include a water vapour permeable and waterproof membrane, as described above, and thus provide for water proofness of the laminar structure 10, and also for a barrier against other liquids and gases, while still maintaining the laminar structure 10 water vapor permeable. For a more detailed description of the functional layer, see the description above.
(107) The additional functional layer 40 is applied to the second layer 24 in a low temperature bonding process by using adhesive spots 44, in order to avoid activation of the laminar structure 10 when the functional layer 40 is applied. A functional layer 40 may be attached to the first layer 22 and/or to the second layer 24.
(108) FIG. 8a shows a simplified and schematic cross-sectional view of a fabric composite 50 including a laminar structure 10 as shown in FIG. 7a. The fabric composite 50 comprises a plurality of layers arranged to each other, seen from an outer side A of a garment made with such fabric composite 50: (1) an outer heat protective shell layer 36 having an outer side 35 and an inner side 37; (2) a barrier laminate 38 comprising a functional layer 40, the barrier laminate 38 is arranged on the inner side 37 of the outer heat protective shell layer 36; and (3) a laminar structure 10 providing adaptive thermal insulation as shown in FIG. 7a, the laminar structure 10 is arranged on the inner side of the barrier laminate 38.
(109) The outer side A means for all the embodiments in the FIGS. 8a to 8g said side which is directed to the environment.
(110) The barrier laminate 38 includes a functional layer 40 which typically comprises a waterproof and water vapor permeable membrane for example as described above. The functional layer 40 is attached to at least one layer 42 via an adhesive layer 44 (two layer laminate). Layer 42 may be a woven or non-woven textile layer. Adhesive layer 44 is configured such as not to significantly impair breathability of the barrier laminate 38. In further embodiments the barrier laminate 38 comprises two or more textile layers wherein the functional layer is arranged between at least two textile layers (three layer laminate).
(111) FIG. 8a shows that the laminar structure 10 providing adaptive thermal insulation is positioned as the innermost layer of the fabric composite 50. Such innermost liner will be facing the wearer's skin in case the fabric composite 50 is used to manufacture garment. Because of being positioned on the far side with respect to the source of heat, the laminar structure 10 is expected to experience much lower temperatures than existing at the outer shell 36 of the garment. This has a benefit in that the temperature resistance of the materials used for the laminar structure 10 need not be as high as it would be required for material positioned close to the outer shell 36. It has been shown that in such arrangement a relatively precisely controllable adaptive thermal insulation mechanism can be implemented using the laminar structure 10 with first layer 22, second layer 24 and cavity 16 filled with a gas generating agent 18 according to the invention, avoiding unnecessary activation at only moderately increased temperatures, on the one hand, and avoiding a catastrophic failure to activation in cases of only slightly stronger increase in temperature than anticipated for an activating event, on the other hand.
(112) Other configurations of fabrics 50 to which the laminar structure 10 can be applied are shown in FIGS. 8b to 8f:
(113) In FIG. 8b the fabric composite 50 includes an outer layer 36 with an outer side 35 and an inner side 37. A laminar structure 10 providing adaptive thermal insulation is positioned on the inner side 37 of the outer layer 36. The laminar structure 10 comprises a barrier laminate 38 having a functional layer 40 adhesively attached to a textile layer 42 for example by adhesive dots 44, an inner layer 24 forming an innermost liner and envelopes 20 arranged between the barrier laminate 38 and the inner layer 24. The envelopes 20 of the laminar structure 10 are bonded to the inner side of functional layer 40 via a suitable discontinuous adhesive 29, e.g. silicone, polyurethane. The inner layer 24 may comprises one or more textile layers. In this embodiment barrier laminate 38 has the function of the first layer of the laminar structure providing adaptive thermal insulation.
(114) In FIG. 8c the fabric composite 50 includes a laminar structure 10 providing adaptive thermal insulation. The laminar structure 10 comprises an outer layer 36 with an outer side 35 and an inner side 37 and a barrier laminate 38 having a functional layer 40 adhesively attached to a textile layer 42 for example by adhesive dots 44. The laminar structure 10 further comprises envelopes 20 which are arranged between the inner side 37 of the outer layer 36 and the barrier laminate 38. In particular the envelopes 20 are adhesively bonded to the outer side of the textile layer 42 by adhesive dots 29. In this embodiment barrier laminate 38 has the function of the second layer of the laminar structure 10 providing adaptive thermal insulation and outer layer 36 has the function of the first layer of the laminar structure 10 providing adaptive thermal insulation. The composite 50 further comprises an inner layer 48 which may comprise one or more textile layers.
(115) In FIG. 8d the fabric composite 50 includes a laminar structure 10 providing adaptable thermal insulation. The laminar structure 10 comprises an outer layer 36 with an outer side 35 and an inner side 37 and a barrier laminate 38 having a functional layer 40 adhesively attached to a textile layer 42 for example by adhesive dots 44. The laminar structure further comprises envelopes 20 which are bonded to the inner side 37 of the outer layer 36 for example by a discontinuous adhesive in the form of adhesive dots 29. In this embodiment barrier laminate 38 has the function of the second layer of the laminar structure 10 providing adaptive thermal insulation and outer layer 36 has the function of the first layer of the laminar structure 10 providing adaptive thermal insulation. The composite 50 further comprises an inner layer 48 which may comprise one or more textile layers.
(116) The insulation capability of the individual layers can be adjusted as required for a particular application, e.g. by area weight, thickness, number of layers.
(117) In FIG. 8e the fabrics composite 50 comprises a laminar structure 10 including a first layer 22 and a second layer 24 with a plurality of envelopes 20 in between as shown in FIG. 6a. Further the fabric composite 50 includes a barrier laminate 38 forming the outer shell of the composite 50 and being positioned on the outer side of the laminar structure 10. The barrier laminate 38 comprises an outer layer 36 and a functional layer 40 adhesively attached to the inner side of the outer layer 36 for example by polyurethane adhesive dots 44.
(118) The fabrics composite 50 in FIG. 8f is similar to the fabric composite of FIG. 8e. In this embodiment the barrier laminate 38 has an additional inner textile layer 42 attached to the functional layer 40 such that the functional layer 40 is embedded between outer textile layer 36 and textile layer 42. The textile layer 42 might be for a fire resistant liner made of 125 g/m.sup.2 Aramide Viscose FR blend 50/50 woven.
(119) FIG. 9 shows a fire fighter's jacket 52 including fabric composite 50 as shown in FIGS. 8a-8f. Other garments which may comprise fabrics 50 according to invention include jackets, coats, trousers, overalls, shoes, gloves, socks, gaiters, headgear, blankets, and the like or parts of them. The fabric composite may be used in other articles as well, for example in tents or the like.
(120) FIG. 10 shows a schematic sketch of an apparatus 300 to measure increase in distance D between the first layer 22 and the second layer 24 when the laminar structure 10 is being brought from the unactivated condition into the activated condition. In this context FIG. 11 shows a schematic sketch of a laminar structure in the form of a test piece 60 to be used with the apparatus of FIG. 10 for measuring the increase in distance D between the first layer 22 and the second layer 24 when the laminar structure 10 is being brought from the unactivated condition into the activated condition. The test piece 60 is shown in plan view in FIG. 11. A cross-sectional view thereof corresponds to the cross sections shown in FIGS. 6a and 6b. FIG. 11 shows the laminar structure 10 in the unactivated condition.
(121) The test piece 60 used in the test described below has the following configuration:
(122) The test piece 60 forms a quilted structure with: (a) a first layer (22) made of 55 g/m.sup.2 spun-laced nonwoven of aramid fiber (available as Vilene Fireblocker from the company Freudenberg, Germany) (b) a second layer (24) (not visible in FIG. 11), arranged underneath the first layer (22), made of 125 g/m.sup.2 aramid viscose woven (available as Nomex Viscose FR blend 50/50 woven from the company Schueler, Switzerland)
(123) The first and second layers 22, 24 have a size of 140 mm (length L)140 mm (width W). The first and second layers 22, 24 are connected by a plurality of stitched seams 62a-62d, 64a-64d, thus forming a quilted composite. The stitched seams are formed by a single needle lock stitch. In this way, 9 pockets 25 are formed by the quilted composite 60. The pockets 25 each have the shape of a square with a side length of a=40 mm. Each of these pockets 25 receives a respective one of the envelopes 20 made as described above. Single envelopes 20 as shown in FIGS. 2d, 3a have been used to carry out the test measurements. Such envelopes 20 have a slightly elliptical shape when seen from above with larger axis of ellipse b1=23 mm, and smaller axis of ellipse b2=20 mm). 9 envelopes 20 are arranged between the first and the second layers 22, 24 such that a single envelope 20 is spaced to at least one neighbour envelope 20 by one of said stitched seams 62a-62d, 64a-64d. Each of the pockets 25 receives one envelope 20. The envelopes 20 are inserted into the pockets 25 without being fixed to the first layer 22 or second layer 24.
(124) Each of the envelopes is filled with 0.03 g of 3M NOVEC 1230 Fire Protection Fluid (chemical formula: CF.sub.3CF.sub.2C(O)CF(CF.sub.3).sub.2) as gas generating agent according to method 2 described above with respect to FIGS. 2a to 2d.
(125) A method for measuring thickness change of such test piece is as follows:
(126) Setup of Measurement Apparatus:
(127) The arrangement for measuring a thickness change of the test piece 60 in response to a change in temperature is shown in FIG. 10. The arrangement comprises a apparatus 300 with a base 302, a heating plate 304, a top plate 306, and a laser based distance measuring device 314.
(128) The heating plate 304 is connected to a heating apparatus (plate 300 mm500 mm out of a Erichsen, doctor blade coater 509/MC/1+heating control Jumo Matec, with controller Jumo dtron16, connected to 220V/16 A).
(129) Test piece 60 is laid flat on the heating plate 304.
(130) Top plate 306 has the form of a flat disk with a diameter of 89 mm and is made of Monolux 500 (available from Cape Boards & Panels, Ltd., Uxbridge, England) or an equivalent material. Top plate 306 has a weight of approx 115 g. Top plate 306 is laid flat on top of the test piece 60.
(131) Laser based distance measuring device 310 includes a frame 312 and a distance laser device 314 (laser sensor: Leuze ODSL-8N 4-400-S 12 which is connected to a A/D converter Almemo 2590-9V5 having a reading rate of 3 measurements per second, the A/D converter translates the 0-10 V output of the laser sensor into a 0-400 mm distance reading, accuracy: 0.2 mm on a plain plate). The frame 312 is mounted to the base 302. The distance laser device 314 is and has mounted to a top arm of the frame in such a way that the distance laser device 314 emits a laser beam 316 towards the top surface of the top plate 306 and receives a reflected beam 318. The distance laser device 314 is able to detect a distance h between the distance laser device 314 and the top surface of top plate 306. Preferably, laser beam 316 is emitted orthogonally to top surface of top plate 306.
(132) Temperature gradient of plate 304 is lower than 2K across the plate in the range of the measurement.
(133) Measurement Procedure:
(134) Test is done at room temperature, i.e. controlled climate of 23 C. and 65% relative humidity. (a) Top plate 306 is placed directly onto heating plate 304 (without test piece 60) to obtain a zero reading h_0. (b) Then, test piece 60 is placed in between heating plate 304 and top plate 306. Heating plate 304 is heated to a temperature above ambient temperature and 5K below the expected activation temperature of the gas generating agent (e.g up to 44 C. in case of 3M Novec 1230 Fire Protection Fluid as gas generating agent) to obtain an initial height reading h_1. Thickness of test piece 60 (corresponding to distance between first layer 22 and second layer 24 in unactivated condition) is D0=h_0h_1. (c) Temperature of heating plate is increased in steps of 5K, after each new step is adjusted, distance h is read after 1 minute to calculate a thickness change h_1h. This procedure is repeated until the maximum expansion of the test piece 60 is reached. Maximum expansion is considered to be reached if thickness change h_1h in at least two consecutive 5K steps is identical within 0.4 mm (which is twice the accuracy of the distance measurement tool). Reading h_max is obtained. Thickness of test piece 60 (corresponding to distance between first layer 22 and second layer 24 in activated condition) is D1=h_0h_max. Increase in thickness of test piece 60 (corresponding to increase in distance between first layer 22 and second layer 24 in activated condition with respect to unactivated condition) is D1D0=h_1h_max.
(135) In the example of test pieces that are able to undergo a plurality of activation/deactivation cycles the following test procedure is available:
(136) Thickness Reversibility Method:
(137) Set-up of thickness measurement apparatus, as described above, is used. (a) Top plate 306 is placed directly onto heating plate 304 (without test piece 60) to obtain a zero reading h_0. (b) Then, test piece 60 is placed in between heating plate 304 and top plate 306. Heating plate 304 is heated to a temperature above ambient temperature and 5K below the expected activation temperature of the gas generating agent (e.g up to 44 C. in case of 3M Novec 1230 Fire Protection Fluid as gas generating agent) to obtain an initial height reading h_1. Thickness of test piece 60 (corresponding to distance between first layer 22 and second layer 24 in unactivated condition) D0=h_0h_1. (c) Heating cycle: Target temperature of heating plate 304 is set to a temperature 30 C. above the boiling point of the gas generating agent in the envelope 20 and heating plate 304 is heated with a heating rate of 1 K/min. Increase in thickness (corresponding to increase in distance D between first layer 22 and second layer 24) is measured by distance laser device 314 every 10 s. When heating plate 304 reaches target temperature this temperature is maintained for about 10 min and reading of increase in thickness is continued. After 10 min final increase in thickness is measured (corresponding to distance between first layer 22 and second layer 24 in activated condition of gas generating agent). (d) Cooling cycle: Target temperature of heating plate 304 is set to room temperature and heating plate 304 is cooling down by the environment within 1 hour. Decrease in thickness (corresponding to decrease in distance D between first layer 22 and second layer 24) is measured by distance laser device 314 every 10 s. When heating plate 304 reaches target temperature this temperature is maintained for about 10 min and reading of decrease in thickness is continued. After 10 min final decrease in thickness is measured (corresponding to distance between first layer 22 and second layer 24 in unactivated configuration).
(138) Heating cycle (c) and cooling cycle (d) are repeated 3 times. Each time thickness increase at topmost temperature and thickness decrease at lowermost temperature are measured.
(139) A result of the thickness reversibility test for one heating cycle and one cooling cycle is shown in FIG. 12 in the form of a distance D vs. temperature T diagram. It can be seen that a hysteresis loop is produced. From the topmost plateau of this hysteresis loop the distance D1 between the first layer 22 and second layer 24 in the activated configuration, and from the lowermost plateau distance D0 between the first layer 22 and second layer 24 in the unactivated configuration can be inferred.
(140) For reversible envelopes with a liquid gas generating agent, the following functionality test is available for single envelopes 20: (a) 2 buckets are prepared. Each bucket is filled with 2 liters of liquid. The first bucket acts as a cold bath and the second bucket acts as a hot bath. The temperatures for the cold bath and the hot bath should be chosen with respect to the activation temperature of the gas generating agent and the onset temperature of condensation/freezing of the gas generating agent. If in one example the gas generating agent is a liquid and the boiling/condensing temperature range is from 47 to 52 C. then a cold bath temperature of 25 C. and a hot bath temperature of 80 C., using water as the liquid in the hot bath and the cold bath, is preferred. (b) The envelope 20, filled with the gas generating agent 18, is held with a pincer and put it into the hot bath, until the envelope 20 will inflate. (c) After inflation is complete, inflated envelope 20 is removed from the hot bath immediately and the thickness of the inflated envelope is estimated using a frame with an opening of the expected thickness. Such frame should be made of a material with a low thermal conductivity. As an example, in case the expected thickness of the inflated envelope is 5.5 mm, then using a frame with an opening of 5 mm height and 30 mm width can show that the envelope has reached at least 5 mm (d) The envelope is then put into the cold bath, until it collapses it again. Cycles (b) to (d) are repeated until the inflation is no longer reaching the gap of the frame indicating that functionality of the envelope becomes impaired. After every 10 repetitions the temperature of the liquids inside the 2 buckets is controlled and adjusted to the target, if necessary.
Example of a Fabric Composite:
(141) Example 1, a fabric composite sample 50, according FIG. 8a was produced, comprising an outer shell in the form of a heat protective layer 36 made of 200 g/m.sup.2 Nomex Delta T woven available from company Fritsche, Germany; a barrier laminate 38 in the form of a Fireblocker N laminate (145 g/m.sup.2) available from company W.L. Gore & Associates GmbH, Germany and a laminar structure 10 in the form of the fabric composite sample 60 according to FIG. 11.
(142) A reference sample was produced using the same set-up as example 1 without filling the envelopes 20 with gas generating agent 18.
(143) The following test results were obtained with example 1 and the reference sample:
(144) TABLE-US-00001 Example 1 Reference example EN367-HTI24-mean [s] 26.4 17.3 RHTI24 mean [s] 25.4 20.5 weight per area [g/m.sup.2] 591 580 RET [m.sup.2 Pa/W] 21.6 21.6
(145) EN367-HTI24-mean refers to heat transfer index at 80 W/m.sup.2, as defined in DIN EN 367 (1992). This quantity describes the time it takes to obtain an increase of 24 K in temperature at the second side (inner side) of a sample fabric as shown in FIG. 11 when the first side is subject to a heat source of 80 W/m.sup.2 with a flame.
(146) RHTI24 mean refers to radiative heat transfer index at 40 W/m.sup.2, as defined in DIN-EN-ISO 6942 (2002-9). This quantity describes the time it takes to obtain an increase of 24 K in temperature at the second side (inner side) of a sample fabric as shown in FIG. 11 when the first side is subject to a radiative heat source of 40 W/m.sup.2 with a radiation source with a temperature of 1100 C.
(147) RET refers to water vapor transmission resistance, as defined above.
