NOVEL PROCESS FOR PRODUCING COMPOSITE MATERIALS

Abstract

A process is disclosed for the preparation of multilayered composite materials comprising, as components: (A) a backing material, (B) optionally at least one tie layer and (C) a polymer layer,
wherein a polymer layer (C) is formed using a mold, optionally at least one organic adhesive is applied all over or partially to backing material (A) and/or to polymer layer (C) and then polymer layer (C) is bonded with backing material (A) in point, strip or two-dimensional fashion, polymer layer (C) and/or at least one tie layer (B) being prepared from aqueous polymer dispersions which comprise at least one crosslinking agent C and from 0.1 to 5% by weight of at least one solvent selected from dipropylene glycol dimethyl ether and/or 1,2-propanediol diacetate.

Claims

1. A process for the preparation of multilayered composite materials comprising, as components: (A) a backing material, (B) optionally at least one tie layer and (C) a polymer layer, wherein polymer layer (C) is formed using a mold, optionally at least one organic adhesive is applied all over or partially to backing material (A) and/or to polymer layer (C) and then polymer layer (C) is bonded with backing material (A) in point, strip or two-dimensional fashion, polymer layer (C) and/or at least one tie layer (B) being prepared from aqueous polymer dispersions which comprise at least one crosslinking agent C and from 0.1 to 5% by weight of at least one solvent selected from dipropylene glycol dimethyl ether and/or 1,2-propanediol diacetate.

2. The process according to claim 1, wherein crosslinking agent C does not comprise any blocked polyisocyanates.

3. The process according to claim 1, wherein polymer layer (C) is a polyurethane layer.

4. The process according to claim 1, wherein the aqueous polymer dispersions comprise the at least one crosslinking agent C, the crosslinking agent C being added to an aqueous polyurethane dispersion as a 1 to 80% by weight solution of the at least one crosslinking agent C in dipropylene glycol dimethyl ether and/or 1,2-propanediol diacetate.

5. The process according to claim 1, wherein the aqueous polymer dispersions comprise the at least one crosslinking agent C, the crosslinking agent C being added to the aqueous polymer dispersions 1 minute to 10 hours before the application of the aqueous polymer dispersions to the mold or the backing material.

6. The process according to claim 3, wherein the polyurethane layer (C) exhibits capillaries which extend over an entire thickness of the polyurethane layer (C).

7. The process according to claim 1, wherein the backing materials (A) are leather, textiles, artificial leather, foams, cellulose materials, stone, metal films, plastic films, spacer knits or nonwovens.

8. The process according to claim 3, wherein the polyurethane layer (C) exhibits a pattern.

9. The process according to claim 3, wherein the polyurethane layer (C) exhibits a velvety appearance.

10. The process according to claim 1, wherein the at least one tie layer (B) is an open-work layer of a cured organic adhesive.

11. The process according to claim 3, wherein polyurethane layer (C) is formed using a silicone mold.

12. The process according to claim 11, wherein the silicone mold is a silicone mold structured using laser engraving.

13. The process according to claim 1, wherein wells are incorporated in the mold in a structuring of the mold using a laser, which wells exhibit an average depth in the range from 50 to 250 m and a center-to-center separation in the range from 50 to 250 m.

Description

EXAMPLES

Example 1

Preparation of Aqueous Polymer Formulation 1 for Polymer Layer (C)

[0204] The following components were stirred together with a laboratory stirrer for 10 minutes in the sequence mentioned below (see table 1): [0205] 1. 1000 g of aqueous polyurethane dispersion (total solids content: 35.5% w/w), based on aliphatic isocyanates and polyether/polycarbonate with a Shore A hardness of 55-60 [0206] 2. 30 g of aqueous pigment dispersion (carbon black) (10.0% w/w) [0207] 3. 50 g of crosslinking agent: water-dispersible polyfunctional isocyanate (base hexamethylene diisocyanate polyisocyanurate, oligomers in solvent 70% w/w).

Example 2

Preparation of Aqueous Polymer Formulation 2 for Tie Layer (B)

[0208] The following components were stirred together with a laboratory stirrer for 10 minutes in the sequence mentioned below [0209] 1. 1000 g of aqueous polymer dispersion based on polyurethane and also polymeric acrylic acid ester/acrylonitrile (total: 40% w/w) [0210] 2. 30 g of aqueous pigment dispersion (carbon black) (10.0% w/w) [0211] 3. 40 g of crosslinking agent: water-dispersible polyfunctional isocyanate (base hexamethylene diisocyanate polyisocyanurate, oligomers in solvent 70% w!w).

Example 3

General Procedure for the Preparation of a Composite Material

[0212] Stage 1: Preparation of the Polymer Layer (C)

[0213] The aqueous polymer formulation 1 from example 1 was, within 10 seconds, sprayed (airless process) uniformly, with 85-115 g/m.sup.2, onto a preheated (80-120 C.) structured silicone mold, which was adhesively bonded to an aluminum sheet with a thickness of 1.5 mm, and then dried.

[0214] Stage 2: Preparation of the Polymer Tie Layer (B) on Polymer Layer (C)

[0215] The mold coated with polymer layer (C) in stage 1 and dried was heated up to 100 C. and, within 60 seconds, coated as follows with the polymer tie layer B.

[0216] The aqueous polymer formulation 2 from example 2 was, within 10 seconds, sprayed (airless process) uniformly, with 85-115 g/m.sup.2, onto the silicone mold precoated in stage 1 and preheated (80-120 C.), and then dried for 5 seconds. The dried polymer layers from stages 1 and 2 were then, within 60 seconds, combined with a backing material (see below) in order to prepare the multilayered composite material (CM).

[0217] Stage 3: Preparation of the Multilayered Composite Material with a Backing Material (A)+Polymer Tie Layer (B)

[0218] The backing material (A) (woven polyester with foam lining) was prepared with a sprayed polymer tie layer B on one side (on the polyester side), which was produced from the aqueous polymer formulation 2 from example 2 as follows.

[0219] The aqueous polymer formulation 2 from example 2 was sprayed (airless process) uniformly at ambient temperature, within 10 seconds, with 60-85 g/m.sup.2, onto the dry backing material (A), and then dried for 5 seconds. The dried backing material (A) with polymer tie layer was directly laid, with the tie layer side, on the mold prepared in stages 1 and 2, heated up (80-110 C.), molded at 3 bar for 20 seconds, in order to produce the multilayered composite material.

[0220] The multilayered composite material, together with the mold, was cooled to a temperature of <40 C. and the multilayered composite material (of polymer layer C, polymer tie layer B and backing material A) was released from the mold.

[0221] Test Variants CM1-CM2

[0222] The following multilayered composite materials (CM1-CM2) were prepared according to example 3. In this connection, the same polyisocyanate based on hexamethylene diisocyanate polyisocyanurate was used in all stages as crosslinking agent, but in different solvents, namely propylene carbonate for CM1 and in (dipropylene glycol dimethyl ether+1,2-propanediol diacetate in the weight ratio of 42:58) for CM2.

TABLE-US-00001 TABLE 1 Materials used in tests CM1 to CM2 Multilayered composite material Polyfunctional isocyanate CM1 Hexamethylene diisocyanate, oligomers in propylene carbonate CM2 Hexamethylene diisocyanate, oligomers in dipropylene glycol dimethyl ether + 1,2-propanediol diacetate 42:58

[0223] The composite materials CM1 and CM2 were subjected to the tests mentioned in table 2. The results are found in table 2.

TABLE-US-00002 TABLE 2 Properties of the composite materials from CM1 and CM2; results correspond, unless otherwise indicated, to grades 1 to 5, in which 5 = no damage/change; 1 = severe damage Product CM1 CM2 Haptics 0 value 5 5 Haptics after exposing 3 times (DIN 53360) 2-3 4 Permanent folding behavior 100 000 4-5 4-5 (DIN 53351) Damage after exposing 3 times and 30 000 3 4 permanent folding behavior (DIN 53351) Separation force of the coating [N/cm] 13.8/15.0 14.4/13.9 longitudinal/transverse (DIN 53357) Abrasion test Martindale 20 000 (12 kPa) 4-5/4-5 4-5/4-5 (DIN EN ISO 12947-1) sample/woven Abrasion test Martindale 50 000 (12 kPa) 4/4 4/4 (DIN EN ISO 12947-1)