Polyurethane coating for airbag and method for producing the same

Abstract

This invention provides a polyurethane coating for airbags and its preparation method. The coating uses a polyurethane coating material comprising a primer A and a topcoat B, wherein the topcoat B contains a nano-silica dispersion. This material effectively solves the problem of poor tear resistance in polyurethane coatings and can be used to prepare airbag coatings.

Description

Technical Field

[0001] This invention belongs to the field of automotive airbag coatings, specifically relating to a polyurethane coating for airbags and its preparation method. Background Technology

[0002] Airbags are essential passive safety devices in automobiles. In the event of a collision, the airbag inflates instantly to prevent injury to the occupants. Airbags are made from a fabric backing material coated with a primer and topcoat, then folded and rolled up before being placed on the ignition system. Since a car typically lasts for more than six years, the folded airbag coating must have excellent aging resistance. Furthermore, it must not tear during inflating; otherwise, the coating will be damaged, resulting in insufficient inflation pressure and ineffective protection. Currently, waterborne polyurethane has gained a foothold in the airbag coating field due to its unique aging resistance and extremely low TVOC. However, the inventors have also discovered that current airbag coatings still suffer from poor tear resistance. Summary of the Invention

[0003] In view of the problems existing in the prior art, one of the objectives of the present invention is to provide a tear-resistant polyurethane coating material that can effectively solve the problem of poor tear resistance of polyurethane coatings.

[0004] To achieve its purpose, the present invention adopts the following technical solution:

[0005] A polyurethane coating material comprising a primer A composition and a topcoat B composition;

[0006] The primer A component comprises:

[0007] (1) Waterborne polyurethane resin

[0008] (2) Defoamer

[0009] (3) Crosslinking agent

[0010] (4) Thickener

[0011] The topcoat B component includes:

[0012] (1) Waterborne polyurethane resin

[0013] (2) Defoamer

[0014] (3) Crosslinking agent

[0015] (4) Thickener

[0016] (5) Nano silica dispersion

[0017] (6) Lubricant.

[0018] The inventors discovered that the tearing that occurs the moment the airbag inflates is due to the adhesion of the airbag coating material during airbag preparation. Further research revealed that nano-silica dispersions have excellent compatibility with polyurethane; the small-particle-size dispersion can bind and coat polyurethane particles, and the dried slurry film provides excellent anti-adhesion properties, thus offering superior tear resistance.

[0019] In one embodiment of the present invention, the isocyanate in the aqueous polyurethane resin of the primer A and topcoat B is selected from aliphatic isocyanates, preferably one or more of 4,4'-dicyclohexylmethane diisocyanate (HMDI), isophorone diisocyanate (IPDI), and hexamethylene diisocyanate (HDI).

[0020] In one embodiment of the present invention, the polyol in the waterborne polyurethane resin of the primer A and topcoat B is selected from polycarbonate polyols with a functionality of 2-4 and a molecular weight of 1000-3000; preferably, the polyurethane resin in the primer A has a 100% modulus of 1-2 MPa and a resin elongation at break of 1000%-1500%, preferably Wanhua Chemical's T7355A; preferably, the polyurethane resin in the topcoat B has a 100% modulus of 3-6 MPa, preferably Wanhua Chemical's T7355B.

[0021] In one embodiment of the present invention, the thickener for the primer A and topcoat B is a pseudoplastic nonionic polyurethane thickener, preferably Wanhua. U905 U605 One or more of U300. The additives are commonly used in the art, and similar technical effects can be achieved by using other additives.

[0022] In one embodiment of the present invention, the nano-silica dispersion in the topcoat B composition has a particle size of 5-40 nm, a solid content of 30-50%, and a pH value of 7-11; preferably, the amount of nano-silica dispersion added is 0.5-2 times the mass of the waterborne polyurethane resin in the topcoat B composition.

[0023] In one embodiment of the present invention, the slip agent in the topcoat B composition is one or more of polyether-modified organosilicon, polysiloxane-modified organosilicon, and talc; preferably, the polyether-modified organosilicon is XM-5278; preferably, the amount of slip agent added is 1-6% of the mass of the waterborne polyurethane resin in the topcoat B composition. The additive is a commonly used additive in the art, and similar technical effects can be obtained by using other additives.

[0024] In one embodiment of the present invention, component A comprises: 100 parts of waterborne polyurethane, 2-4 parts of crosslinking agent, 0.2-0.5 parts of defoamer, and 0.5-2 parts of waterborne thickener; component B comprises: 100 parts of waterborne polyurethane, 2-4 parts of crosslinking agent, 0.2-0.5 parts of defoamer, 0.5-3 parts of waterborne thickener, 50-200 parts of nano-silica dispersion, and 1-6 parts of slip agent.

[0025] Another object of the present invention is to provide a use for a polyurethane coating material.

[0026] The use of a polyurethane coating material, wherein the material is the polyurethane coating material described above, and the polyurethane coating material is used to prepare an airbag coating.

[0027] Another object of the present invention is to provide an airbag coating.

[0028] An airbag coating, prepared using the aforementioned polyurethane coating material, the coating comprising a primer and a topcoat, wherein the topcoat composition contains a nano-silica dispersion.

[0029] Another object of the present invention is to provide a method for preparing a polyurethane coating.

[0030] A method for preparing a polyurethane coating, wherein the coating uses the polyurethane coating material described above, or is another coating described above, and the preparation method includes the following steps:

[0031] S1: Apply the primer A mixture to the airbag fabric substrate and dry the primer coating.

[0032] S2: Apply topcoat component B onto the base coat of S1 and dry the topcoat.

[0033] In one embodiment of the invention, the viscosity of the primer A composition in S1 at 25°C is 20,000-50,000 cps (e.g., Brookfield DV2T, rotor No. 64 / 20 rpm).

[0034] In one embodiment of the present invention, the dry weight sizing amount of the primer A composite material in S1 is 20-60 g / m³. 2 Preferred concentration: 30-40g / m 2 .

[0035] In one embodiment of the present invention, the drying temperature in S1 is 90-170°C.

[0036] In one embodiment of the invention, the viscosity of the topcoat B compound in S1 at 25°C is 10,000-30,000 cps (e.g., Brookfield DV2T, rotor #63 / 5 rpm).

[0037] In one embodiment of the present invention, the dry weight sizing amount of the topcoat B composite material in S2 is 4-20 g / m². 2 Preferred concentration: 6-15g / m 2 .

[0038] In one embodiment of the present invention, the drying temperature in S2 is 150-180°C.

[0039] Another object of the present invention is to provide an airbag material containing a polyurethane coating.

[0040] An airbag material containing a polyurethane coating, wherein the airbag material is prepared by using the above-mentioned polyurethane coating material to prepare the coating, or contains the above-mentioned airbag coating, or contains the coating prepared by the above-mentioned preparation method.

[0041] Another object of the present invention is to provide an airbag.

[0042] An airbag, wherein the airbag is coated with the polyurethane coating material described above, or contains the airbag coating described above, or contains a coating prepared by the preparation method described above, or uses the airbag material described above.

[0043] Compared with the prior art, the positive effects of the present invention are as follows:

[0044] The present invention solves the problem of poor tear resistance of polyurethane coatings. Without the present invention, the coatings adhere together and cannot be peeled off, or when peeled off, the coatings peel off significantly, scoring 0-4 points according to the scoring rules. However, after using the present invention, the coating can be peeled off in 0 seconds according to the ISO5978 standard, scoring 5 points. Detailed Implementation

[0045] The present invention will be described in further detail below, but the invention is not limited thereto.

[0046] raw material

[0047] (1) Waterborne polyurethane resin:

[0048] Primer: Wanhua Chemical T7355A, isocyanate: isophorone diisocyanate (IPDI), polyol: polycarbonate polyol with a functionality of 3 and a molecular weight of 2000, resin 100% modulus 1MPa, elongation 1100%, particle size 130nm, solid content 45%.

[0049] Wanhua Chemical 7396, the isocyanate is isophorone diisocyanate (IPDI), the polyol is: a polyether polyol with a functionality of 2 and a molecular weight of 1000, the resin has a 100% modulus of 1.7 MPa, an elongation of 700%, a particle size of 145 nm, and a solid content of 50%.

[0050] Topcoat: T7355B, isocyanate: hexamethylene diisocyanate (HDI), polyol: polycarbonate polyol with a functionality of 2 and a molecular weight of 3000, resin 100% modulus 3.5MPa, elongation 550%, particle size 105nm, solid content 35%.

[0051] Wanhua Chemical 7566, the isocyanate is isophorone diisocyanate (IPDI) and hexamethylene diisocyanate (HDI), the polyol is: a polyester polyol with a functionality of 2 and a molecular weight of 2000, the resin has a 100% modulus of 1.3 MPa, an elongation of 800%, a particle size of 110 nm, and a solid content of 35%.

[0052] Wanhua Chemical 7230, the isocyanate is 4,4'-dicyclohexylmethane diisocyanate (HMDI), the polyol is a polyether polyol with a functionality of 3 and a molecular weight of 2000, the resin has a 100% modulus of 3 MPa, an elongation of 600%, a particle size of 105 nm, and a solid content of 35%.

[0053] (2) Crosslinking agents: Covestro Imprafix 2794, Langyi CA01;

[0054] (3) Defoamers: TEGO 810, TEGO 902W;

[0055] (4) Thickener: Pseudoplastic nonionic polyurethane thickener, namely... U905, U605, U300;

[0056] (5) Nano silica dispersion: Commercially available HS-830, particle size 10nm, solid content 30%, pH 9.5-10.5; Commercially available HS-840, particle size 30nm, solid content 40%, pH 9-11;

[0057] (6) Slip agents: commercially available polysiloxane-modified organosilicon Dow Corning DC-51, commercially available polyether-modified organosilicon XM-5278, and commercially available talc.

[0058] Test methods

[0059] Coating weight: Tested according to ISO 3801 standard;

[0060] Tear strength: Tested according to ISO 13937-2.

[0061] Bending friction: Tested according to ISO 5981.

[0062] Anti-adhesion: Tested according to ISO 5978 standard;

[0063] Tensile strength of adhesive film: Tested according to ASTM D412 standard, at a test speed of 100 mm / min;

[0064] 100% modulus of film: Tested according to ASTM D412 standard, at a test speed of 100 mm / min;

[0065] Film elongation: Tested according to ASTM D412 standard at a test speed of 100 mm / min.

[0066] Example

[0067] Example 1

[0068] (1) Prepare waterborne polyurethane primer A component, which, by weight, includes:

[0069] Waterborne polyurethane T7355A, 100g;

[0070] Crosslinking agent 2794, 2g;

[0071] The total amount of defoamers 810 and 902w is 0.5g, of which 0.3g of 810 and 0.2g of 902w are added.

[0072] A total of 1.6g of water-based thickeners U605 and U905 were added, of which 1.2g of U605 and 0.4g of U905 were added; the viscosity of the mixture at 25°C was thickened to 23,000-25,000 cps (Brookfield DV2T, rotor No. 64 / 20rpm), and the mixture was allowed to stand to defoam.

[0073] (2) Prepare waterborne polyurethane primer B component, which, by weight, includes:

[0074] Waterborne polyurethane T7355B, 100g;

[0075] Crosslinking agent CA01, 2g;

[0076] The total amount of defoamers 810 and 902w is 0.4g, of which 0.3g of 810 and 0.2g of 902w are added.

[0077] A total of 2g of water-based thickeners U605 and U300, of which 1.2g of U605 and 0.8g of U300 are added, thickens the mixture to a viscosity of 13,000-15,000 cps at 25°C (Brookfield DV2T, rotor No. 63 / 5rpm);

[0078] Nano silica dispersion HS-830, 150g;

[0079] Lubricant XM-5278, 6g;

[0080] (3) Fix the fabric substrate to the nail plate, adjust the blade coating gap, and control the dry basis weight of the primer to 35 g / m². 2 The surface coating has a weight of 10g / m². 2 Apply the primer evenly to the substrate, and use a stepped temperature increase: 90℃ / 20s, 120℃ / 20s, 170℃ / 30s. After drying, apply the topcoat to the primer using the same method, and then dry at 180℃ / 10s before cutting and testing.

[0081] Example 2

[0082] (1) Prepare waterborne polyurethane primer A component, which, by weight, includes:

[0083] Waterborne polyurethane 7396, 100g;

[0084] Crosslinking agent 2794, 2g;

[0085] The total amount of defoamers 810 and 902w is 0.5g, of which 0.3g of 810 and 0.2g of 902w are added.

[0086] A total of 1.6g of water-based thickeners U605 and U905 were added, of which 1.2g of U605 and 0.4g of U905 were added; the viscosity of the mixture at 25°C was thickened to 23,000-25,000 cps (Brookfield DV2T, rotor No. 64 / 20rpm), and the mixture was allowed to stand to defoam.

[0087] (2) Prepare waterborne polyurethane primer B component, which, by weight, includes:

[0088] Waterborne polyurethane T7355B, 100g;

[0089] Crosslinking agent CA01, 2g;

[0090] The total amount of defoamers 810 and 902w is 0.4g, of which 0.3g of 810 and 0.2g of 902w are added.

[0091] A total of 2g of water-based thickeners U605 and U300, with 0.3g of U605 and 0.3g of U300 added, thickens the mixture to a viscosity of 10,000-12,000 cps at 25°C (Brookfield DV2T, rotor No. 63 / 5rpm).

[0092] Nano silica dispersion HS-830, 50g;

[0093] Lubricant XM-5278, 6g;

[0094] (3) Fix the fabric substrate to the nail plate, select an appropriate blade coating gap, and control the dry basis weight of the primer to be 35 g / m². 2 The surface coating has a weight of 10g / m². 2 Apply the primer evenly to the substrate, then use a stepped temperature increase: 90℃ / 20s, 120℃ / 20s, 170℃ / 30s. After drying, apply the topcoat on top of the primer using the same method. Dry at 180℃ / 10s, then cut and test.

[0095] Example 3

[0096] (1) Prepare waterborne polyurethane primer A component, which, by weight, includes:

[0097] Waterborne polyurethane 7396, 100g;

[0098] Crosslinking agent 2794, 2g;

[0099] The total amount of defoamers 810 and 902w is 0.5g, of which 0.3g of 810 and 0.2g of 902w are added.

[0100] A total of 1.6g of water-based thickeners U605 and U905 were added, of which 1.2g of U605 and 0.4g of U905 were added; the viscosity of the mixture at 25°C was thickened to 23,000-25,000 cps (Brookfield DV2T, rotor No. 64 / 20rpm), and the mixture was allowed to stand to defoam.

[0101] (2) Prepare waterborne polyurethane primer B component, which, by weight, includes:

[0102] Waterborne polyurethane 7230, 100g;

[0103] Crosslinking agent CA01, 2g;

[0104] The total amount of defoamers 810 and 902w is 0.4g, of which 0.3g of 810 and 0.2g of 902w are added.

[0105] A total of 2g of water-based thickeners U605 and U300, of which 1.2g of U605 and 0.8g of U300 are added, thickens the mixture to a viscosity of 13,000-15,000 cps at 25°C (Brookfield DV2T, rotor No. 63 / 5rpm);

[0106] Nano silica dispersion HS-830, 200g;

[0107] Lubricant XM-5278, 6g;

[0108] (3) Fix the fabric substrate to the nail plate, select an appropriate blade coating gap, and control the dry basis weight of the primer to be 35 g / m². 2 The surface coating has a weight of 10g / m². 2 Apply the primer evenly to the substrate, then use a stepped temperature increase: 90℃ / 20s, 120℃ / 20s, 170℃ / 30s. After drying, apply the topcoat on top of the primer using the same method. Dry at 180℃ / 10s, then cut and test.

[0109] Example 4

[0110] (1) Prepare waterborne polyurethane primer A component, which, by weight, includes:

[0111] Waterborne polyurethane T7355A, 100g;

[0112] Crosslinking agent 2794, 4g;

[0113] The total amount of defoamers 810 and 902w is 0.5g, of which 0.3g of 810 and 0.2g of 902w are added.

[0114] A total of 1.6g of water-based thickeners U605 and U905 were added, of which 1.2g of U605 and 0.4g of U905 were added; the viscosity of the mixture at 25°C was thickened to 23,000-25,000 cps (Brookfield DV2T, rotor No. 64 / 20rpm), and the mixture was allowed to stand to defoam.

[0115] (2) Prepare waterborne polyurethane primer B component, which, by weight, includes:

[0116] Waterborne polyurethane T7355B, 100g;

[0117] Crosslinking agent CA01, 2g;

[0118] The total amount of defoamers 810 and 902w is 0.4g, of which 0.3g of 810 and 0.2g of 902w are added.

[0119] A total of 2g of water-based thickeners U605 and U300 were added, with 1.2g of U605 and 0.8g of U300, to thicken the mixture to a viscosity between 13,000 and 15,000 cps (Brookfield DV2T, rotor #63 / 5rpm).

[0120] Nano silica dispersion HS-830, 150g;

[0121] Lubricant XM-5278, 1g;

[0122] (3) Fix the fabric substrate to the nail plate, adjust the blade coating gap, and control the dry basis weight of the primer to 35 g / m². 2 The surface coating has a weight of 4g / m 2 Apply the primer evenly to the substrate, and use a stepped temperature increase: 90℃ / 20s, 120℃ / 20s, 170℃ / 30s. After drying, apply the topcoat to the primer using the same method, and then dry at 160℃ / 10s before cutting and testing.

[0123] Comparative Example 1

[0124] The nano-silica dispersion in the topcoat B composition was replaced with HS-840 with a larger particle size, and the addition amount and other parameters were the same as in Example 1.

[0125] Comparative Example 2

[0126] In the topcoat B composition, nano-silica dispersion is not used, but otherwise it is the same as in Example 1.

[0127] Table 1

[0128]

[0129]

[0130] Note: For performance ratings of 0-5, 0 is the worst and cannot be peeled off, 0-3 is the coating peeling off, 4-5 is peelable and the coating does not peel off, and 5 is peelable with a 50g weight in 0 seconds; the airbag bending friction value is a range that includes test error.

[0131] Compared with Example 1, Comparative Example 1 used HS-840 (20-30nm) with a larger particle size, while HS-830 has a particle size of 8-15nm. The smaller the particle size, the better the anti-blocking performance and the better the wear resistance. Compared with Example 1, Comparative Example 2 did not use nano silica dispersion, and the anti-blocking effect was very poor, and the coating peeled off.

[0132] It is readily understood that the above embodiments are merely illustrative examples for clear explanation and do not imply that the invention is limited thereto. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A polyurethane coating material, characterized in that, The material comprises a primer A mixture and a topcoat B mixture; The primer A component comprises: (1) Waterborne polyurethane resin (2) Defoamer (3) Crosslinking agent (4) Thickener; The topcoat B component includes: (1) Waterborne polyurethane resin (2) Defoamer (3) Crosslinking agent (4) Thickener (5) Nano silica dispersion (6) Lubricant.

2. The material of claim 1, wherein, The isocyanate in the waterborne polyurethane resin of the primer A and topcoat B is selected from aliphatic isocyanates, preferably one or more of 4,4'-dicyclohexylmethane diisocyanate (HMDI), isophorone diisocyanate (IPDI), and hexamethylene diisocyanate (HDI). And / or, the polyol in the waterborne polyurethane resin of the primer A and topcoat B is selected from polycarbonate polyols with a functionality of 2-4 and a molecular weight of 1000-3000. Preferably, the polyurethane resin in the primer A component has a 100% modulus of 1-2 MPa and a resin elongation at break of 1000%-1500%, preferably Wanhua Chemical's T7355A. Preferably, the polyurethane resin in the topcoat B compound has a 100% modulus of 3-6 MPa, preferably Wanhua Chemical's T7355B.

3. The material according to claim 1 or 2, characterized in that, The thickening agent of the base coating A composition and the top coating B composition is a pseudoplastic nonionic polyurethane thickening agent, preferably Wanhua U905、 U605、 U300 one or more of.

4. The material according to any one of claims 1 to 3, characterized in that, The nano-silica dispersion in the surface coating B composition has a particle size of 5-40 nm, a solid content of 30-50%, and a pH value of 7-11. Preferably, the amount of the nano-silica dispersion added is 0.5-2 times the mass of the waterborne polyurethane resin in the topcoat B composition.

5. The material according to any one of claims 1 to 4, characterized in that, The slip agent in the topcoat B composition is one or more of polyether-modified organosilicon, polysiloxane-modified organosilicon, and talc. Preferably, the polyether-modified organosilicon is XM-5278; Preferably, the amount of slip agent added is 1-6% of the mass of the waterborne polyurethane resin in the topcoat B composition.

6. The material of any one of claims 1-5, wherein, Component A contains: 100 parts waterborne polyurethane, 2-4 parts crosslinking agent, 0.2-0.5 parts defoamer, and 0.5-2 parts waterborne thickener; Component B contains: 100 parts waterborne polyurethane, 2-4 parts crosslinking agent, 0.2-0.5 parts defoamer, 0.5-3 parts waterborne thickener, 50-200 parts nano-silica dispersion, and 1-6 parts slip agent.

7. Use of a polyurethane coating material, wherein the material is the polyurethane coating material according to any one of claims 1-6, and the polyurethane coating material is used to prepare an airbag coating.

8. An airbag coating prepared using the polyurethane coating material according to any one of claims 1 to 6, characterized in that The coating comprises a primer and a topcoat, wherein the topcoat composition contains a nano-silica dispersion.

9. A process for the production of a polyurethane coating, which coating is applied from a polyurethane coating material as claimed in any of claims 1 to 6, or is a coating as claimed in claim 8, characterized in that, The preparation method includes the following steps: S1: Apply the primer A mixture to the airbag fabric substrate and dry the primer layer; S2: Apply topcoat component B onto the base coat of S1 and dry the topcoat.

10. The method of claim 9, wherein, The viscosity of the S1 primer A composite material at 25℃ is 20,000-50,000 cps; and / or, the dry weight pick-up of the primer A composition in S1 is 20-60 g / m 2 , preferably 30-40 g / m 2 ; And / or, the drying temperature in S1 is 90-170℃.

11. The preparation method according to claim 9, characterized in that, The viscosity of the topcoat B composite material described in S1 at 25°C is 10,000-30,000 cps; And / or, the dry weight of the S2 surface coating B combination material is 4-20 g / m 2 , preferably 6-15 g / m 2 ; And / or, the drying temperature in S2 is 150-180℃.

12. An airbag material containing a polyurethane coating, wherein the airbag material is prepared by using the polyurethane coating material according to any one of claims 1-6, or includes the airbag coating according to claim 8, or includes the coating prepared by the preparation method according to any one of claims 9-11.

13. An airbag, wherein the airbag is coated with a polyurethane coating material according to any one of claims 1-6, or comprises the airbag coating according to claim 8, or comprises a coating prepared by the preparation method according to any one of claims 9-11, or uses the airbag material according to claim 12.

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