Integrated insulation extrusion and extrusion technology for window and door systems

Abstract

Extruded plastic profiles with integrated insulation, the method for extruding such products, and the windows and doors made with such plastic extrusions. The plastic extrusions may additionally include a low heat build-up capstock system comprising an acrylic cap and pigment system that is substantially IR transparent. The extruded plastic profiles with integrated insulation are recyclable using conventional plastic extrusion process and are fully weldable in conventional window and door manufacturing.

Claims

1. A method of co-extruding an insulated extrudate with a plurality of integral foamed insulating strands, the method comprising the steps of: feeding a first thermoplastic resin suitable for use in a structural fenestration component into a first extruder; feeding a second thermoplastic resin suitable for integrated insulation into a second extruder; and outputting the first and second extruders to an extrusion die and extruding the extrudate from the extrusion die, where the extrusion die forms a structural fenestration extrusion formed of the first thermoplastic resin and wherein the structural fenestration extrusion defines at least one hollow interior portion of a constant profile, and, wherein the extrusion die substantially fills the hollow interior portion of the structural extrusion with an integrated insulation formed of a plurality of strands of foamed second thermoplastic resin that crowd together to define a plurality of air pockets running in a length of the extrudate between the strands while also integrating with the structural extrusion to define an integrated insulating extrudate.

2. The method of claim 1, wherein the plurality of air pockets of the integrated insulation running in the length of the extrudate are formed by the extrusion die with a plurality of individual outlets having a die land between 0.05 and 0.2 inches.

3. The method of claim 1, further comprising the step of feeding a third thermoplastic resin that is significantly transmissive of solar infrared radiation into a third extruder and outputting the third extruder into the extrusion die so that the third thermoplastic resin forms a dark-colored capstock layer of less than about 10 thousandths of an inch thick on a surface of the structural extrusion formed of the first thermoplastic resin.

4. The method of claim 3, wherein the extrusion die forms the dark-colored capstock portion into a layer less than about 8 thousandths of an inch thick and the first thermoplastic resin contains between about 8 and 11 parts titanium dioxide per hundred base resin.

5. A method of coextruding an insulated extrudate with integral foamed insulating strands, the method comprising the steps of: extruding a first resin to define a fenestration structure to be insulated; the fenestration structure having a longitudinal direction; extruding a second resin as a plurality of foamed strands disposed within the fenestration structure; allowing the foamed strands to expand and crowd together within the structure to be insulated to define a plurality of longitudinal air pockets disposed within the fenestration structure and between the foamed strands; and integrating at least some of the foamed strands to the fenestration structure to form an integral insulated structure.

6. The method of claim 5, further comprising the step of selecting the first resin and the second resin to be recyclable together.

7. The method of claim 6, further comprising the step of selecting the first resin and the second resin to be resins comprised of polyvinyl chloride.

8. The method of claim 5, further comprising the step of extruding the first and second resins from the same extrusion die.

9. The method of claim 8, further comprising the step of forming the foamed strands and longitudinal air pockets with an extrusion die having a plurality of outlets having a die land between 0.05 and 0.2 inches.

10. The method of claim 9, further comprising the step of substantially filling the fenestration structure with the expanded foamed strands.

11. The method of claim 9, further comprising the step of adding a blowing agent to the second resin to achieve a density below 0.4 g/cc.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a plan view of an extrusion line of a type used with the inventive method.

(2) FIG. 2 is an exploded view of downstream side of a multi-plate extrusion die for use in a preferred embodiment of the inventive method.

(3) FIG. 3 is a view of the flow of the various thermoplastic resin feed stocks in one of the plates of the multi-plate extrusion die shown in FIG. 2.

(4) FIG. 4 is a view the flow of the various feed stocks in one of the plates of the multi-plate extrusion die shown in FIG. 2.

(5) FIG. 5 is a view of the flow of the various feed stocks in one of the plates of the multi-plate extrusion die shown in FIG. 2.

(6) FIG. 6 is a view the flow of the various feed stocks in one of the plates of the multi-plate extrusion die shown in FIG. 2.

(7) FIG. 7 is a cut-away view of a two possible die orifices for use in one of the plates of the multi-plate extrusion die shown in FIG. 2.

(8) FIG. 8. is a view of the inventive extrusions showing profiles showing alternate embodiments of the integrated insulation.

(9) FIG. 9 are top right perspective views, which are broken in the center indicating indefinite length, of an example of the preferred embodiment of the inventive extrusion, showing the extrusion with and without the inventive integrated insulation.

(10) FIG. 10 are top right perspective views, which are broken in the center indicating indefinite length, of another example of a preferred embodiment of the inventive extrusion showing the inventive extrusion with and without the inventive integrated insulation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(11) The inventive extrudate comprises a structural extrusion formed of a first thermoplastic resin suitable for use in the fenestration industry and contains at least one hollow interior portion, has a constant profile, and extends to an indefinite length. An integrated insulation formed of a second thermoplastic resin substantially fills the hollow portion of the structural extrusion and in a preferred embodiment this integrated insulation is foamed and this foam further contains a plurality of air pockets running in the length of the extrudate. The first thermoplastic resin and the second thermoplastic resin are compatible and recyclable together and the structural extrusion and the integrated insulation are coextruded through an extrusion die to form the inventive extrudate. It is a further preferred embodiment to further include a dark-colored capstock of a third thermoplastic resin that is significantly transmissive of solar infrared radiation and that covers at least a portion of the structural extrusion, where the dark-colored capstock is less than about 10 thousandths of an inch thick and more preferably between 4 and 8 thousandths of an inch thick. An alternate embodiment includes a fourth thermoplastic resin to make up portions of the structural extrusion.

(12) The method of producing the extrudate with integral insulation described in paragraph above, requires the use of a plastics extrusion line and comprises feeding a first thermoplastic resin suitable for use in a structural component in the fenestration industry into a first extruder, feeding a second thermoplastic resin suitable for integrated insulation into a second extruder, outputting the first and second extruders to an extrusion die extruding the extrudate. This extrusion die forms a structural extrusion formed of the first thermoplastic resin, suitable for use in the fenestration industry, containing at least one hollow interior portion, of a constant profile, and extending to an indefinite length, and substantially fills a hollow portion of the structural extrusion with an integrated insulation formed of a second thermoplastic resin. In a preferred embodiment, the second thermoplastic resin of the integrated insulation is foamed and shaped to further contain a plurality of air pockets running in the length of the inventive extrudate. In a still further preferred embodiment, the method comprises feeding a third thermoplastic resin that is significantly transmissive of solar infrared radiation into a third extruder and outputting the third extruder into the extrusion die so that the third thermoplastic resin forms a dark-colored capstock layer of less than about 10 thousandths of an inch thick and more preferably between 4 and 8 thousandths of an inch thick on a surface of the structural extrusion. A further alternate embodiment may include a fourth thermoplastic resin output by a fourth extruder to make up portions of the structural extrusion, such as portions of the structural extrusion that are not subject to the elements, or portions of the structural extrusion that would not typically be visible when the inventive extrusion has been manufactured into a window for use in a residential or commercial structure. In such a case, the fourth thermoplastic resin could be less costly perhaps due to not requiring additives for UV stability such as TiO.sub.2 or due to loosened requirements for color uniformity or otherwise.

(13) In addition to the various extruders discussed above, appropriate calibrators, pullers and saws are needed for the production of the above described inventive extrusions and method. Additionally, stresses imparted during the extrusion calibration process may affect the apparent color of the pigment systems of the preferred embodiments including the dark-colored capstock layer. Thus, the present invention also embodies a means to eliminate those stresses, and therefore provide a consistent visual color, by applying heat after the product exits the extruder calibrator.

(14) Tailoring the heat build-up performance of an extrusion is conducted by essentially three means. First, the thickness of the dark-colored capstock is manipulated to minimize IR absorbance as NIR initially passes through the dark-colored capstock and as it is reflected off of the substrate back through the dark-colored capstock. This manipulation must also be done in a manner that preserves the visual color of the capstock. Second, the substrate is manipulated to provide the requisite IR reflectance, most commonly by manipulating the loading of TiO2 but also with consideration of other substrate constituents. Third, the pigments in the dark-colored capstock required to impart particular colors should be optimized to minimize their absorbance of NIR. In practice, all three means must be optimized for a particular capstock/color/substrate combination to yield a functional final product.

(15) A preferred and useful pigment and cap material combination for the dark colored capstock material is available from Lanier Color Company and can be shown to posses the IR and weatherability properties desired, namely that the pigment system is substantially transmissive of NIR and such a pigment system is used in the inventive examples discussed, hereinbelow. The body of the dark colored capstock is Kaneka Corporation's proprietary XM20, which is an extrusion grade acrylic. This acrylic has a melt index value between approximately 13 g/10 min. and 20 g/10 min. as tested using ASTM D1238 standard at 230 degrees Celsius and 3.8 kg mass. This useful Lanier pigment system uses a black base pigment that provides a suitable base to which other pigments can be added to achieve a desired particular color or chroma (e.g., forest green or bronze) as is well understood by color houses and those of ordinary skill in the art. Individual pigments may be reflective or transmissive of NIR so long as, overall, the pigment system is substantially NIR transmissive. The preferred Lanier pigment system, or a substitute that is substantially NIR transparent, would be suitable for use in the present invention and would achieve the ends of the present invention. The dark colored capstock may be solid colors or may be formed into wood grains or other finishes with textured appearances. Further, touch-up paints that are substantially NIR transparent based on similar NIR transmissive pigment systems may be used to repair minor scratches or gaps in the dark colored capstock such as may occur at the corner welds in a window frame.

(16) The inventor believes that PVC lineals currently used in residential window frames would likely be a suitable structural extrusion for this invention. A suitable formulation for the integrated insulation is shown in Table 1, below.

(17) TABLE-US-00001 TABLE 1 Parts Per Hundred Resin Ingredient Supplier (by weight) PVC Resin SE-650 - Shintech 100.0 Tin Butyl Stabilizer RT4458 - Reagens 1.2 Ester Base Lubricant SA 0817B - Strucktol 1.5 Acrylic Modifier PA 40 - Kaneka 20.0 CaCO3 Filler Optifil JS - JM Huber 6.0 CBA Pigment 473LD - KibbeChem 5.0 Total Parts 133.7
To this formulation, a person of ordinary skill in the art would typically add a suitable blowing agent in an amount sufficient to achieve a density preferably below 0.4 g/cc and more preferably between 0.2 and 0.4 g/cc. The amounts and type of blowing agent is determined by the extrusion equipment used, the process conditions, and the particular shape and details of a particular extrusion as is well understood by those of ordinary skill in the art. The inventor has in the past used Color Matrix Foamazol F-92 product as a blowing agent.

(18) FIG. 1 illustrates an extrusion line 10 suitable for practicing the inventive process. An extrusion line suitable for use in an embodiment of the inventive process is disclosed in The extrusion line 10 consists of at least two extruders including primary extruder 20 (first extruder) that includes a feed hopper 12 that drops into a feed column 14 which further connects to a pre-mixer 16. Port 18 also feeds into feed column 14 for the addition of micro ingredients such as a blowing agent. Alternatively, such micro ingredients can be added at hopper 19 directly into the premixer 16. The ingredients that reach premixer 16 are fed directly into the mouth of primary extruder 20. A integrated insulation extruder (second extruder) and, in a preferred embodiment a dark colored capstock extruder (third extruder), and in a still further embodiment an alternative structural extrusion extruder (fourth extruder) having essentially these same features as described above for the primary extruder are further disclosed.

(19) A multi-plate extrusion die 22 is further described below with reference FIG. 2, but multi-plate extrusion die 22 is operatively attached to the primary extruder 20 the output of the primary extruder 20. The extrusion is shown at reference numeral 24 after it has exited multi-plate extrusion die 22. Extrusion 24 then enters calibrator 26 which is of the ordinary type used in plastic profile extrusion and which includes sizer plates which form extrusion 24 into its final form and spray nozzles to cool and solidify extrusion 24.

(20) After extrusion 24 exits calibrator 26, it enters heat treatment tube 28. Heat treatment tube 28 may be formed of PVC pipe approximately three feet long and of a diameter to allow easy clearance for extrusion 24 to pass through it. Preferably, at the entrance and exits of heat treatment tube 28, leister heaters 30 blow hot air into the tube and over extrusion 24. Alternatively, the heat treatment tube 28 can also be served by an IR heating tube to heat the exterior surface of extrusion 24. Further, the leister heaters 30 could be replaced with heat guns, IR heaters, radiant heaters or other devices that would heat the interior of the heat treatment tube 28 and thereby heat the surface of extrusion 24. The heat treatment tube 28 could be replaced with just Liester heaters 30 or their substitutes that were noted above should bow of extrusion 24 not be a significant concern. It should be understood that heat treatment tube 28 is used only as necessary to correct for bow or to correct for surface color issues as has been described below and, thus, may not always be used. Extrusion 24 then continues on to puller 32 and saw 34 that are entirely conventional extrusion equipment long in use in the art.

(21) One purpose for the heat treatment tube 28 is to eliminate the occurrence of streaking in the dark colored capstock where upon inspection, there will be streak of a differing shade in a line traveling down the length of extrusion 24 and it should be understood that heat treatment tube 28 or its substitutes would not be needed should there be no color streaking. This streaking is believed to be caused by stresses formed in the surface of the dark colored capstock by the calibration and cooling process which of necessity causes the surface of the dark colored capstock to contact the interior surface of calibrator 26 and causes the part to cool most quickly on the surface and, more gradually, for the interior portions of the extrusion to cool relatively more slowly. This streaking most typically is of a red shade. This streaking can be easily removed by heat treatment of the surface of dark colored capstock and the use of the heat treatment tube, as described above, heats the entire surface of extrusion 24 thus avoiding causing extrusion 24 to bend or bow as can be caused by heating only one side of the extrusion such as by directly blowing hot air onto a surface of extrusion 24. Heating the surface of extrusion 24 to approximately 145 .degree. F. to 150 .degree. F. will remove the color streaking observed in the dark colored cap disclosed herein and has found that Leister heaters 30 blowing air at approximately 225 .degree. F. into the tube has raised the surface of examples of extrusion 24 to the desired 145 .degree. F. to 150 .degree. F.

(22) FIG. 2 is an exploded view of the downstream sides of the individual plates of the multi-plate extrusion die 22 for use in a preferred embodiment of the inventive method. FIG. 2 illustrates a multi-plate die assembly 22 shown in exploded form consisting of individual die plates 36, 38, 40, and 42 and various intermediate plates connecting the same for manufacturing the inventive extrudate. The manner of use of such dies is well known to those of ordinary skill in the thermoplastic extrusion art. Nevertheless, it is sufficient to state that the multi-plate die assembly 22 shown in FIG. 2 is intended for use with a plurality of conventional extruders, such as conventional twin screw extruders, each of which includes a mixer or hopper for accepting a thermoplastic resin feed stock, a conduit for connecting the hopper with a preheater for controlling the temperature of an admixture of the feed stock in the hopper, in the case of the second thermoplastic resin used for the integrated insulation, optionally an inlet for introducing foaming agents for a foamed component. The multi-screw chamber of each extruder is connected to an appropriate input on the die assembly plates shown in FIG. 2 for producing an embodiment of the extrudate with integrated insulation.

(23) As best seen in FIG. 2, one of the hereinabove described extruders (not shown) is fluidly connected to an introductory plate 36 for introduction of a first thermoplastic resin for forming the structural extrudate through the multi-plate die assembly 22. FIGS. 3, 4, 5, and 6 show the flow of the first thermoplastic resin for forming the structural extrudate and the flow of the second thermoplastic resin forming the integrated insulation as practiced with a hollow, thin-walled PVC extrudate.

(24) Flow at approximately the midpoint within plate 38 of the multi-plate die assembly 22 is shown at FIG. 3. Inlet 44 for introducing the second thermoplastic resin suitable for integrated insulation 46, a suitable formulation for such shown in Table 1, from the output of second extruder and the inlet 48 for the first thermoplastic resin for the structural extrusion 50, 52 is shown in FIGS. 2 and 3. As was described above, portions of the structural extrusion may consist of a fourth thermoplastic resin of lower cost and could be fed through to 50 in this exemplary extrusion from a fourth extruder from an un-shown inlet in a similar manner to inlet 44. The portions of the structural extrusion at 52, or all of the structural extrusion 50, 52, are fed through inlet 48 of the multi-plate die assembly 22 from the output of the first extruder. The multiple channels flowing the structural extrusion 50, 52 are shaped to help equalize the flow and to allow the insertion of the integrated insulation 46 within the interior of structural extrusion 50, 52.

(25) Flow at approximately the midpoint within plate 40 of the multi-plate die assembly 22 (shown in FIG. 2) is shown at FIG. 4. The structural extrusion 50, 52 is much closer to shape of its intended final form. The intended integrated insulation 46 can be seen in the interior of structural extrusion 50, 52.

(26) The entrance to plate 42 of the multi-plate die assembly 22 (shown in FIG. 2) is shown at FIG. 5 for the preferred embodiment of integrated insulation 46. The exit of plate 42 of the multi-plate die assembly 22 (shown in FIG. 2) is shown at FIG. 6 for the preferred embodiment of integrated insulation 46. The typical preferred final shape of the preferred embodiment of integrated insulation 46 is shown in two different window component extrusions at FIGS. 9 and 10. The integrated insulation 46 is broken up into a group of ribbons or strands beginning at the entrance to plate 42 shown at FIG. 5. At the exit to plate 42, shown at FIG. 6, integrated insulation 46 is twenty-two individual stands of the second thermoplastic resin. Note that the integrated insulation may easily be left out of the extrusion to save costs, where such performance is not needed, merely by not adding the second extruder. This allows the option of a less costly extrusion without integrated insulation without adding further die or tooling costs.

(27) In this preferred embodiment, the individual stands of the integrated insulation 46 expand due to the blowing agent and due to the lower pressure at the exit of multi-plate die assembly 22 at plate 42, best seen in FIG. 6. In the preferred embodiment, the individual stands of the integrated insulation 46 expand until they crowd together and mesh together where they meet while leaving a series of air pockets 54 running the length of the extrudate with integrated foam insulation. If the flow of the integrated insulation 46 is too high or the foam is too aggressive, then the strands will push tightly together leaving no air pockets.

(28) FIG. 7 shows cut-away partial side views of the possible interior views of plate 42 of the multi-plate die assembly 22. The entrance side is shown on the left at 56 and the exit shown at 58 showing the flow of an individual strand of integrated insulation 46 through plate 42 where the size of the exit orifice is preferably between 0.08 and 0.10 inches shown at 60 and where the orifices are typically spaced between 0.08 and 0.10 inches apart and from a wall of the structural extrusion 50, 52. The left-hand version shown is typically referred to as free-foam version allowing the maximum flow of an individual strand of the integrated insulation 46. The right hand version has a die land 62 which is a parallel portion of walls of the die. Such a die land 62 will serve to increase the drag on the individual strand of the integrated insulation 46 reducing the flow rate through plate 42. By shortening the die land 62, one can increase the flow of an individual strand of the integrated insulation 46 allowing tuning of the multi-plate die assembly 22 to allow the formation and retention of the air pockets 54 seen in FIGS. 9 and 10.

(29) Inventor has found that individual strands of the integrated insulation 46 that exit plate 42 of the multi-plate die assembly 22 through orifices between 0.08 and 0.10 inches and spaced between 0.08 and 0.10 inches apart typically need a die land of 0.05 to 0.2 inches. The angle of the orifice prior to the die land has not been found to be critical.

(30) FIG. 8 shows two alternate embodiments of possible integrated insulation 46. Instead of extruding individual strands that partially merge together leaving air pockets, here, the orifices in the die plate would be narrow slots. These slots can be arranged to allow multiple air pockets and low overall density of the integrated insulation 46.

(31) The structural extrusion 50, 52 and the integrated insulation can be easily recycled by grinding up the extrusions as with a standard, hollow PVC extrusion, while using an aspirator on the ground materials to substantially remove the substantially lower density integrated insulation. The recycled and substantially uniform structural extrusion materials can then be reused in the extrusion process.

(32) The integrated insulation 46 of the inventive process and extrudate substantially match or exceed commercially available polyethylene and polyurethane insulation products. As such, the windows made with the inventive extrudate and triple pane glass packs have tested to a 0.15 U-factor/R6.5 window substantially exceeding current EnergyStar requirements of a 0.3 U-factor. The manufacturing of the inventive extrudate into a completed window does not require any additional or changed fabrication steps from standard hollow PVC window, while offering substantially better performance.