3-DIMENSIONAL MANUFACTURE OF POROUS AND WATERPROOF MEMBRANE

Abstract

The disclosure relates to seamless manufacturing processes for 3-dimensional waterproof and breathable porous polymer membranes by spraying, dip-coating or painting a substrate with a dispersion having polymer, coated or non-coated particles and diluent and removing the particles by dissolution thus creating porosity after the 3D coating/shaping. The disclosure further relates to dispersions to obtain such membranes, to polymer membranes obtained, to shaped articles containing such membranes; to the use of such membranes, shaped articles and intermediates.

Claims

1. A method of manufacturing a polymer membrane: said polymer membrane is 3-dimensional and seamless; is either a membrane attached to a substrate, or is a free-standing membrane; is porous and having a pore size of 500-2,000 nm, said method comprising the steps of: a. providing a dispersion having a viscosity of 400-1500 mPas at 25° C. and 200 rpm, the dispersion comprising one or more diluents in an amount of at least 40 wt.%; one or more polymers dissolved therein; one or more coated or non-coated particles dispersed therein; optionally one or more additives dissolved therein; and optionally one or more dyes dispersed therein, and whereby the coated particles are pre-manufactured; are selected from the group consisting of organic salts, metal salts, metal oxides and combinations thereof, or organic crystals; the coating material of said coated particles is selected from the group of poly maleic anhydrides, carboxylic acids, aryl-alkoxy-silanes alkyl-aryl-alkoxy-silanes and alkyl-alkoxy-silanes; and have a particle size in the range of 5-15,000 nm, preferably 2000-8000 nm, and whereby the non-coated particles are selected from the group consisting of organic salts, metal salts, metal oxides and combinations thereof, or organic crystals; have a particle size in the range of 5 - 15,000 nm, preferably 2000-8000 nm; b. coating a 3-dimensional substrate with said dispersion, thus obtaining a layer partly or fully covering said substrate; c. subjecting the obtained material to a drying step, thus obtaining a dried material; d. optionally repeating steps (b) and (c), thus obtaining a multi-coated material; e. optionally subjecting the thus obtained material to a polymerisation or cross-linking step; f. removing said one or more particles by a dissolution step, thus obtaining a porous polymer membrane attached to a substrate; and g. optionally removing the obtained polymer porous membrane from said substrate without destruction of the 3-dimensional shape, thus obtaining a free-standing 3D membrane; and wherein said 3D structure comprise three distinctive coordinates y, z and x and thereby excludes 2D structures and bent 2D structures; and wherein said polymer has a solubility in a solvent of at least 1 g/l, preferably 10 g/l.

2. The method of claim 1, where said coating is spray coating.

3. The method of claim 1, wherein said method does not involve a “closing step” which is detectable in a textile product or alters the polymer membrane; said closing step particularly selected from bonding, sewing, welding, gluing, knitting, stitching; and/or said method does not involve a phase separation step; and/or said application method does not involve a 2-dimensional pore forming step before assembly into 3-dimensional product; and/or said application creates the pores (step (f)) after application of the liquid membrane precursor (step (b)) into the final shape; and/or said coating step (b) is selected from the group consisting of spraying, painting, printing (including 3D printing), and dip-coating; and/or said dissolution (f) is performed in 90 min or less.

4. The method of claim 1, where the polymer membrane covers the outer or inner surface of a clothing, either fully or on predetermined areas.

5. The method according to claim 1, wherein said metal salts are selected from the group consisting of carbonates, hydrogencarbonates, sulphates, halogenides, nitrates and phosphates and said metal oxides are selected from ZnO and MgO; and/or said organic crystals are selected from a group consisting of saccharides, preferably glucose, fructose or a combination of both; and/or said coating material is selected from the group of natural fatty acids, anhydride acids, such as poly maleic anhydride acids (PMAH), its homopolymer but also co-polymer containing PMAH) and mixture of PMAH, or carboxylic acids, particularly stearic acid; and/or said diluents are selected from the group consisting of solvents with a b.p. below 200° C.; and/or said substrate is selected from the group consisting of polymers, metals, leather, ceramics, concrete and paper, each coated or uncoated; and/or said 3-dimensional substrate, has the shape of (i) a clothing, such as a hand, feet, torso, leg, or head; (ii) any type of shaped leather object, such as a bag or backpack; (iii) a special electronic parts, furniture, construction.

6. The method according to claim 1, wherein said soluble polymers are selected from the group consisting of polyurethanes, polyesters, polyamides, and polyolefins.

7. The method according to claim 1, wherein said polymer membrane: has a thickness of 0.01 - 1000 microns preferably 1 - 120 microns, most preferably 15-50 microns; and/or has a porosity of 30-80%, preferably 55-65%; and/or has a poremouth size of 5-10,000 nm, preferably 100 - 5000, most preferably 300-1000 nm; and/or has a water column (WC) of at least 4.8 m; and/or has a water vapour transmission rate (WVTR) of at least 500 g/m2 per day; and/or has a water contact angle of at least 50°; is built up of 1-20 layers, preferably 1-4.

8. The method according to claim 1, wherein said dispersion contains: 40 to 99 wt.-% diluents (7); 1 to 20 wt.-% polymers (5); 0.5 to 40 wt.-% coated and/or uncoated particles (6); 0-6 wt-%, preferably 2-4 wt.-% coating material; 0 to 5 wt.-% additives (8); and 0 to 5 wt.-% dyes (9).

9. A porous polymer membrane, wherein said membrane is obtainable by, or obtained by, the method according to claim 1; and/or said membrane has a 3-dimensional shape; and its shape is congruent with a final product; and has a single piece structure without visible assembly artefacts; and has a pore size of 500 - 2000 nm, preferably with unimodal size distribution; and optionally, complies with one or more of the following parameters: a thickness of 0.01 - 1000 microns, preferably 1 - 120 microns, most preferably 15-50 microns; and/or a poremouth size of 5-10,000 nm, preferably 100 - 5000 nm, most preferably 300-1000 nm; and/or a porosity of 30-80%, preferably 55-65%; and/or a water column (WC) of at least 4.8 m; and/or a water vapour transmission rate (WVTR) of at least 500 g/m.sup.2 per day.

10. A woven, non-woven or knitted textile material comprising a polymer membrane according to claim 9, wherein said membrane is directly coated on said 2D textile with specific pattern; or said membrane is directly coated or transferred on said 3D textile, i.e. finished textile product; or said membrane is self-supporting and connected with said textile membrane by gluing or welding; and said membrane being applied on pre-determined positions; e.g. by body-mapping for performance control.

11. A finished textile product, particularly selected from the group of clothing, containers and shoes, said textile product comprising a textile material according to claim 10, or a porous polymer membrane, wherein said membrane is obtainable by, or obtained by, a method of manufacturing a polymer membrane: said polymer membrane is 3-dimensional and seamless; is either a membrane attached to a substrate, or is a free-standing membrane; is porous and having a pore size of 500-2,000 nm, said method comprising the steps of: a. providing a dispersion having a viscosity of 400-1500 mPas at 25° C. and 200 rpm, the dispersion comprising one or more diluents in an amount of at least 40 wt.%; one or more polymers dissolved therein; one or more coated or non-coated particles dispersed therein; optionally one or more additives dissolved therein; and optionally one or more dyes dispersed therein, and whereby the coated particles are pre-manufactured; are selected from the group consisting of organic salts, metal salts, metal oxides and combinations thereof, or organic crystals; the coating material of said coated particles is selected from the group of poly maleic anhydrides, carboxylic acids, aryl-alkoxy-silanes alkyl-aryl-alkoxy-silanes and alkyl-alkoxy-silanes; and have a particle size in the range of 5-15,000 nm, preferably 2000-8000 nm, and whereby the non-coated particles are selected from the group consisting of organic salts, metal salts, metal oxides and combinations thereof, or organic crystals; have a particle size in the range of 5 - 15,000 nm, preferably 2000-8000 nm; b. coating a 3-dimensional substrate with said dispersion, thus obtaining a layer partly or fully covering said substrate; c. subjecting the obtained material to a drying step, thus obtaining a dried material; d. optionally repeating steps (b) and (c), thus obtaining a multi-coated material; e. optionally subjecting the thus obtained material to a polymerisation or cross-linking step; f. removing said one or more particles by a dissolution step, thus obtaining a porous polymer membrane attached to a substrate; and g. optionally removing the obtained polymer porous membrane from said substrate without destruction of the 3-dimensional shape, thus obtaining a free-standing 3D membrane; and wherein said 3D structure comprise three distinctive coordinates y, z and x and thereby excludes 2D structures and bent 2D structures; and wherein said polymer has a solubility in solvent of at least 1 g/l, preferably 10 g/1, and/or said membrane has a 3-dimensional shape; and its shape is congruent with a final product; and has a single piece structure without visible assembly artefacts; and has a pore size of 500 - 2000 nm, preferably with unimodal size distribution; and optionally, complies with one or more of the following parameters: a thickness of 0.01 - 1000 microns, preferably 1 - 120 microns, most preferably 15-50 microns; and/or a poremouth size of 5-10,000 nm, preferably 100 - 5000 nm, most preferably 300-1000 nm; and/or a porosity of 30-80%, preferably 55-65%; and/or a water column (WC) of at least 4.8 m; and/or a water vapour transmission rate (WVTR) of at least 500 g/m.sup.2 per day.

12. A finished textile product according to claim 10, wherein the product is selected from clothing, particularly selected from coats, jackets, trousers, shirts, gloves, socks, shoes, caps; and the membrane is seamless over the whole or parts of the surface of said clothings and has a pore size of 5 - 10,000 nm; and the membrane optionally comprises 1-20 layers of a thickness of 0.01 - 1000 microns; and/or has a breathability of above 500 g/m.sup.2 per day; and/or has a water column of above 4.8 m.

13. A sport shoe comprising a seamless membrane as defined in claim 9; wherein said membrane: was added by spraying, dipping, painting, thus covering the seam in a mid-layer, outer layer or inside layer of the finished garment; or is self-supported and connected with said shoe by gluing, welding or transferring on a mid-layer, outer layer or inside layer of the finished garment; and/or covers all of the surface of the sport shoe or only selected parts of it.

14. A sport garment, particularly selected from jackets, trousers, and gloves, comprising a seamless membrane as defined in claim 9, said membrane was added by spraying, dipping, painting, thus covering the seam in a mid-layer, outer layer or inside layer of the finished garment; is self-supported and connected with said shoe by gluing, welding or transferring on a mid-layer, outer layer or inside layer of the finished garment; covers all of the surface of the garment or only selected parts of it.

15. Use of a dispersion, as defined in claim 1, for manufacturing a 3-dimensional, seamless, porous polymer membrane; or a textile material; or a textile product.

16. A finished textile product, particularly selected from the group of clothing, containers and shoes, said textile product comprising a woven, non-woven or knitted textile material comprising a polymer membrane according to a porous polymer membrane, wherein said membrane is obtainable by, or obtained by, the method according to a method of manufacturing a polymer membrane: said polymer membrane is 3-dimensional and seamless; is either a membrane attached to a substrate, or is a free-standing membrane; is porous and having a pore size of 500-2,000 nm, said method comprising the steps of: a. providing a dispersion having a viscosity of 400-1500 mPas at 25° C. and 200 rpm, the dispersion comprising one or more diluents in an amount of at least 40 wt.%; one or more polymers dissolved therein; one or more coated or non-coated particles dispersed therein; optionally one or more additives dissolved therein; and optionally one or more dyes dispersed therein, and whereby the coated particles are pre-manufactured; are selected from the group consisting of organic salts, metal salts, metal oxides and combinations thereof, or organic crystals; the coating material of said coated particles is selected from the group of poly maleic anhydrides, carboxylic acids, aryl-alkoxy-silanes alkyl-aryl-alkoxy-silanes and alkyl-alkoxy-silanes; and have a particle size in the range of 5-15,000 nm, preferably 2000-8000 nm, and whereby the non-coated particles are selected from the group consisting of organic salts, metal salts, metal oxides and combinations thereof, or organic crystals; have a particle size in the range of 5 - 15,000 nm, preferably 2000-8000 nm; b. coating a 3-dimensional substrate with said dispersion, thus obtaining a layer partly or fully covering said substrate; c. subjecting the obtained material to a drying step, thus obtaining a dried material; d. optionally repeating steps (b) and (c), thus obtaining a multi-coated material; e. optionally subj ecting the thus obtained material to a polymerisation or cross-linking step; f. removing said one or more particles by a dissolution step, thus obtaining a porous polymer membrane attached to a substrate; and g. optionally removing the obtained polymer porous membrane from said substrate without destruction of the 3-dimensional shape, thus obtaining a free-standing 3D membrane; and wherein said 3D structure comprise three distinctive coordinates y, z and x and thereby excludes 2D structures and bent 2D structures; and wherein said polymer has a solubility in solvent of at least 1 g/l, preferably 10 g/l; and/or said membrane has a 3-dimensional shape; and its shape is congruent with a final product; and has a single piece structure without visible assembly artefacts; and has a pore size of 500 - 2000 nm, preferably with unimodal size distribution; and optionally, complies with one or more of the following parameters: a thickness of 0.01 - 1000 microns, preferably 1 - 120 microns, most preferably 15-50 microns; and/or a poremouth size of 5-10,000 nm, preferably 100 - 5000 nm, most preferably 300-1000 nm; and/or a porosity of 30-80%, preferably 55-65%; and/or a water column (WC) of at least 4.8 m; and/or a water vapour transmission rate (WVTR) of at least 500 g/m.sup.2 per day; wherein said membrane is directly coated on said 2D textile with specific pattern; or said membrane is directly coated or transferred on said 3D textile, i.e. finished textile product; or said membrane is self-supporting and connected with said textile membrane by gluing or welding; and said membrane being applied on pre-determined positions; e.g. by body-mapping for performance control; or a polymer membrane according to claim 9.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0155] Further, the present invention will be better understood by reference to FIG. 1. This figure outlines the invention as described herein, specifically process steps of the manufacturing process of 3D waterproof and breathable membrane, here illustrated as a sock. Steps (a) to (g) and Materials (1) to (10) are described in the specification and claims. The invention is further illustrated by the following, non-limiting Examples

DETAILED DESCRIPTION

I. Synthesis

[0156] Polymer mixture of commercially available polymer(s) was obtained by dissolving it/them in a solvent using an external stirrer (IKA®RW 20 digital). The coated or non-coated particles were added to the mixture and the resulting dissolution was run through a ball mill once (WAB Dyno®-Mill Multi Lab at 10 rpm pumping rate and 3800 U/min milling rotation with 1 mm ZrO.sub.2 milling beads) to receive the final polymer solution.

[0157] I.1 Example 1: Ether-based Polyurethane & CaCO3: 600 kg of dispersion (1) were synthetized by dissolving 2 different ether-based polyurethanes in N,N-dimethylacetamide. Specially coated-CaCOS particles were added to the mixture and the dispersion was milled until the required particle size was achieved. The final dispersion is to be degassed in vacuum.

[0158] I.2 Example 2: Ether-based Polyurethane & NaCl: 2 kg of dispersion (1) were synthetized by dissolving 2 different ether-based polyurethanes in N,N-dimethylacetamide. NaCl particles were added to the mixture and the dispersion was milled until the required particle size was achieved. The final dispersion is to be degassed in vacuum.

[0159] 1.3 Example 3: Water-based Polyurethane & CaCO3: 0.5 kg of dispersion (1) were synthetized by using commercially available water-based PU (as liquid dispersion). Specially coated CaCO3 particles were added to the mixture and the dispersion was milled until the required particle size was achieved. The final dispersion is to be degassed in vacuum.

[0160] I.4 Example 4: Poly lactic acid (PLA): 2 kg of dispersion (1) were synthesized by dissolving PLA in tetrahydrofuran (THF). Specially coated-CaCO3 particles were added to the mixture and the dispersion was milled until the required particle size was achieved. The final dispersion is to be degassed in vacuum.

II. Application

[0161] After the synthesis of the dispersion (1) described in I, the liquid membrane is then sprayed, dip-coated or painted onto a substrate (described above).

II.1 Spraying

[0162] General procedure: The substrate (2.2) was placed on a support and the area of spray delimited using paper tape. It was then preheated in a 110° C. oven for more than 5 minutes. Few tens of milliliters of room temperature liquid membrane dispersion (1) were added in a spray gun tank. The spray gun was connected to an air flow whose pressure can be controlled. The pressure was set to 2.5 bars when the gun trigger was fully engaged. The hot substrate (2.2) has then been removed from the oven and the liquid membrane dispersion (1) sprayed onto it to fully cover the desired area. The distance from the gun nozzle with the substrate (2.2) can vary from 5 to 25 cm and the speed of advancement of the gun from 5 to 500 mm/s. After a first monolayer of sprayed liquid membrane (2.1) was applied, the coated support (2) was placed again in the 110° C. oven in order for the solvent to be completely evaporated. Then the dried coated support (3) was removed from the oven and a second layer was applied using the same procedure. This step can be repeated several times until the desired membrane thickness is reached. The dried membrane on the substrate (3), was then placed in a bath to wash out the template particles (6), in the case the dried non-porous film (3.1) is not easily removed from the substrate (3.2). This bath can be acidic depending on the particles (6) used.

[0163] Depending on the final application of the product, the 3D membrane is then removed from the substrate (step e)) after the washing step d), as described in more details below:

[0164] On a mannequin (free-standing membrane): Tests were made with shoe and glove mannequins. The spraying parameters of distance to the sample and speed were rather close (from 5 to 15 cm) and fast (from 250 to 500 mm/s) . The spray pattern made by hand looked homogeneous with an even thickness of the membrane on the whole sample including 3D corners (+/- 5 microns). The resulting samples after following the rest of the general procedure were gently removed from the mannequin, giving a free-standing shaped membrane in one piece.

[0165] On 2D textile: The tests on textile were performed with different types of fabric, e.g. polyester, cotton, polyamide, polypropylene. The procedure was adapted to the behavior of the fabric regarding its thickness, weaving or liquid membrane absorption for instance. The textile was fixed onto a 2D support plate and pre-heated before the spraying process. During this phase, the support was maintained vertically. The distance and speed parameters were rather far (around 15 to 20 cm) and slow (around 5 to 10 mm/s). The spraying pattern was more vertical and horizontal lines to cover all of the surface. The rest of the general procedure was followed.

[0166] On a finished textile product (incl. seam): Two techniques were experimented to achieve a membrane cover of a finished textile product including seams: i) Using the same technique as a 2D spraying on fabric by heating up in advance the sample. For bigger samples that do not fit inside the oven, a heating blow up support structure was used, allowing to spray and dry at the same time.

[0167] ii) Spray first on a mannequin as described in the previous part and thread the sample over the membrane still on its support. Then, spraying some solvent above the fabric sample to soak it with an air flow pressure around 1 bar and replace the sample in a 110° C. oven to dry the solvent out. The rest of the general procedure was followed. This was used, for example, as a transfer possibility of the seamless membrane on a finished textile-based sock.

II.2 Dipping

[0168] General procedure: The substrate (2.2) was placed on a support and the area of dipping delimited using paper tape. The dipping tests were carried out without pre-heating (note that pre-heating the substrate would also work). The liquid membrane dispersion (1) is kept at room temperature. The substrate (2.2) was immersed in the liquid membrane and then dried out at 110° C. in an oven. This step can be repeated several times until the desired membrane thickness is reached. The dried coated object (3) was placed in a bath to wash out the template particles (6), in the case the dried non-porous film (3.1) is not easily removed from the substrate (3.2). This bath can be acidic depending on the particles (6) used.

[0169] Depending on the final application of the product, the 3D membrane is then removed from the substrate (step (g)) after the washing step (f), as described in more details below:

[0170] On a mannequin (free-standing membrane): The hand and shoe mannequins were soaked in a bucket of liquid membrane dispersion (1) then taken out and stayed above the bucket for a while so that the excess flowed back into the bucket before placing it in the oven at 110° C. The thickness of the sample was not constant on all of the shape as the liquid membrane accumulates in the lower parts due to gravity. This can be avoided by moving the sample while it is dried. The rest of the general procedure was followed.

[0171] On a finished textile product (incl. seam): The finished textile product was placed in a container and liquid membrane dispersion (1) was poured over all the desired parts.

[0172] Then the coated object (2) was taken out and stayed above the container for a while so that the excess of membrane flowed back into the container before placing it in the oven at 110° C. For example, around 200 mL of liquid membrane was required for a complete man-size sock. The rest of the general procedure was followed.

II.3 Painting

[0173] General procedure: The substrate (2.2) was placed on a support and the area of paint delimited using paper tape. The painting tests were carried out without pre-heating (note that pre-heating the substrate would also work). A paint brush was soaked in a liquid membrane dispersion (1) tank and a layer was applied on the sample by brushing it. After this layer of paint liquid membrane, the coated object (2) was placed in the 110° C. oven. Then the sample was removed from the oven and a second layer was applied using the same procedure. This step can be repeated several times until the desired membrane thickness is reached. The dried coated object (3) was placed in a bath to wash out the template particles (6), in the case the dried non-porous film (3.1) is not easily removed from the substrate (3.2). This bath can be acidic depending on the particles (6) used.

[0174] Depending on the final application of the product, the 3D membrane is then removed from the substrate (step (g)) after the washing step (f), as described in more details below:

[0175] On 2D textile: The liquid membrane was applied following a direction with the brush for one layer to avoid traces of brush as much as possible. Visual traces are still noticeable after passing through the oven. A second layer was applied following the perpendicular direction and the coated sample (2) was placed again in the oven at 110° C. The rest of the general procedure was followed.

[0176] On a finished textile product (incl. seam): A similar procedure was applied as for 2D textile. The seams of a jacket, for example, were painted with the liquid membrane dispersion (1) following the direction of the seam but also perpendicular to it for a homogeneous coverage. A second layer was applied following using the same directions and the coated object (2) was placed again in the oven at 110° C. The rest of the general procedure was followed.

III. Analytics

[0177] The obtained products described above were destroyed to enable the measurements of the following analytics.

TABLE-US-00001 Performance of the different methods based on Ex1 Techniques WC (m) WVTR (g/m.sup.2/day) spraying free-standing membrane 9.7 1516 8.7 1672 18.5 632 spraying on textile 6.1 860 14.9 779 13.1 1004 7.1 1092 9.9 1212 dipping free-standing membrane -* -* dipping on textile 9.3 1456 painting on textile 12.9 421 * not determined. The results of the free-standing membrane by dipping are assumed to be similar for the sprayed techniques

TABLE-US-00002 Performance of the spraying methods based on Ex 2, 3 and 4 Techniques Ex. # WC (m) WVTR (g/m2/day) spraying free-standing membrane 2 12.5 1048 3 40 612 4 25 926

IV. Viscosity

[0178] In two sets of experiments, 3D membranes were prepared according to this invention by spray coating using the dispersion as described herein and compared to a 3D membrane prepared by spray coating using known dispersions.

[0179] Set 1: A dispersion with 3 different viscosities (high, medium, low) was sprayed on a polyester fabric.

[0180] The visual grade of the sprayed membrane was analysed visually and was rated from 1 to 6, with 6 being represented as no defect, no inhomogeneity and no trespassing of the membrane on the reverse, non-sprayed, side of the fabric.

[0181] The experiment was repeated 3 times per viscosity and std. deviation was determined.

[0182] The success of the sprayed membrane was analysed by their pore size and whether the measurement was possible of not.

[0183] The results are summarized in table 3 below.

TABLE-US-00003 Performance results of the spraying methods based on different viscosities viscosity** visual grade * std. deviation pore size [micron] high, 350 mPa 5.3 0.58 600-1200 medium, 200 mPa 3.7 1.15 600-1200 low, 130 mPa 1.3 0.58 not measurable * on a range of 1 - 6, 6 being perfect; ** 40° C. @ 250 rpm

[0184] Conclusion: The results clearly show the influence of starting material’s viscosity on the membrane performance. While dispersions with high viscosity provide excellent results, dispersions with low viscosity fail in spray coating of a polyester fabric, as the membrane layer shows inhomogeneity and uncontrolled large holes. Therefore, the required pore sizes to achieve the target performances are not measurable.

[0185] Set 2: Inventive and known dispersions were sprayed on a 3D object, the results are compared in table 4.

TABLE-US-00004 experiment observation inventive (polymer dispersion) smooth 3D membrane unimodal size distribution comparative (monomer dispersion) defective 3D membrane, pore size not measurable

[0186] Conclusion: It was found that adjusting viscosity allows reliable manufacturing of 3D membranes with suitable pore size and unimodal size distribution. Previously known dispersions failed under similar conditions.

[0187] While the present disclosure has been illustrated and described with respect to a particular embodiment thereof, it should be appreciated by those of ordinary skill in the art that various modifications to this disclosure may be made without departing from the spirit and scope of the present disclosure.