COMPOSITE MATERIAL COMPOSED OF OUTER LAYER AND POLYURETHANE FOAM LAYER

Abstract

In a process for producing a composite element having at least a covering layer and polyurethane foam, the covering layer is inserted into a mold and a polyurethane reaction mixture is introduced onto the covering layer. The polyurethane reaction mixture is reacted to form a polyurethane foam, wherein the polyurethane reaction mixture is obtained by mixing a) polyisocyanate with b) compounds having isocyanate-reactive OH groups, c) blowing agents including water, d) thickeners and e) catalysts. Bis(N,N-dimethylaminoethoxyethyl) carbamate, N,N,N-trimethyl-N-hydroxyethylbis(aminopropyl ether), N,N,N-trimethyl-N-hydroxyethyl(aminoethyl ether) or mixtures thereof and/or tetramethyldiaminoethyl ether are employed as catalysts and the polyurethane foam has a density of not more than 200 g/dm.sup.3.

Claims

1. A process for producing a composite element comprising at least a covering layer and polyurethane foam, the process comprising inserting the covering layer into a mold, introducing a polyurethane reaction mixture onto the covering layer and reacting the polyurethane reaction mixture to form a polyurethane foam, wherein the polyurethane reaction mixture is obtained by mixing a) polyisocyanate with b) compounds having isocyanate-reactive OH groups, c) blowing agents comprising water, d) thickeners and e) catalysts wherein bis(N,N-dimethylaminoethoxyethyl) carbamate, N,N,N-trimethyl-N-hydroxyethylbis(aminopropyl ether), N,N,N-trimethyl-N-hydroxyethyl(aminoethyl ether) or mixtures thereof and/or tetramethyldiaminoethyl ether are employed as catalysts and the polyurethane foam has a density of not more than 200 g/dm.sup.3.

2. The process according to claim 1, wherein the polyurethane foam has an average thickness averaged over the surface of the covering layer coated with polyurethane foam of not more than one cm.

3. The process according to claim 1, wherein the thickener (d) is a thickener having two primary or secondary amino groups and a molecular weight of less than 500 g/mol.

4. The process according to claim 3, wherein the amino groups are primary amino groups.

5. The process according to claim 3, wherein the amino groups are bonded to aromatic hydrocarbons.

6. The process according to claim 1, wherein the thickener (d) is diethyltoluenediamine.

7. The process according to claim 1, wherein the isocyanates comprise monomeric and polymeric diphenylmethane diisocyanate.

8. The process according to claim 1, wherein the catalysts (e) comprise incorporable polyurethane catalysts.

9. The process according to claim 8, wherein the incorporable catalysts employed are from the group consisting of: bis(N,N-dimethylaminoethoxyethyl) carbamate, N,N,N-trimethyl-N-hydroxyethylbis(aminopropyl ether), N,N,N-trimethyl-N-hydroxyethyl(aminoethyl ether) and mixtures thereof.

10. The process according to claim 1, wherein the compounds having isocyanate-reactive OH groups (b) comprise polyether polyols.

11. The process according to claim 1, wherein the isocyanate index is 90 to 120.

12. A composite element obtainable by a process according to claim 1.

13. A transport means having an interior comprising a composite element according to claim 12.

Description

[0039] The present invention further provides a composite element obtainable by the process according to the invention. Despite a low thickness and low polyurethane foam density these composite elements exhibit no defects even when produced in molds with demanding flow characteristics. The composite elements according to the invention are therefore suitable for use in the interior of means of transport, such as in automobiles, for example as a dashboard, door panel, armrest, floor edging, center console, airbag cover or glovebox.

[0040] The invention is elucidated hereinbelow with reference to examples.

[0041] An instrument panel made of a covering layer of PVC slush skin and a polyurethane foam according to table 1 was produced. To this end the covering layer was inserted into the mold, the polyurethane reaction mixture according to table 1 was mixed by mixing the polyol component composed of polyol, catalyst, DETDA, crosslinker and water with the isocyanate component composed of a mixture of the indicated isocyanates with an isocyanate index of 100 and introduced onto the covering layer. One polyurethane foam having a density of 160 g/l was generated by using 230 g of reaction mixture and one polyurethane foam having a density of 145 g/l was generated by using 200 g of reaction mixture. The mold was then closed. After about 100 seconds the finished composite part was demolded and checked for defects in the polyurethane foam. The following components were employed:

[0042] Polyol 1: Glycerol-started polyether polyol based on ethylene oxide and propylene oxide having an average OH number of 28 mg KOH/g, a functionality of 2.7 and a propylene oxide content based on the total weight of the polyether of 84 wt %.

[0043] Polyol 2: Glycerol-started polyether polyol based on ethylene oxide and propylene oxide having an average OH number of 27 mg KOH/g, a functionality of 2.5 and a propylene oxide content based on the total weight of the polyether of 78 wt %.

[0044] Polyol 3: Glycerol-started polyether polyol based on ethylene oxide and propylene oxide having an average OH number of 55 mg KOH/g, a functionality of 2.7 and a propylene oxide content based on the total weight of the polyether of 87 wt %.

[0045] Polyol 4: Propoxylated dimethylaminopropylamine having an average OH number of 250 mg KOH/g, a functionality of 2.0 and a propylene oxide content based on the total weight of the polyether of 72 wt %.

[0046] Polyol 5: Polyester composed of adipic acid, 1,4-butanediol, isophthalic acid, monoethylene glycol having an average OH number of 55 mg KOH/g.

[0047] Catalyst 1: incorporable amine catalyst Jeffcat ZF10 from Huntsman

[0048] Catalyst 2: incorporable amine catalyst Polycat 15 from Air Products

[0049] Catalyst 3: incorporable amine catalyst Polycat 58 from Air Products

[0050] DETDA: diethyltoluenediamine

[0051] Crosslinker: triethanolamine

[0052] Iso 1: methylenediphenyl diisocyanate having an NCO content of 33.5 wt % and an average functionality of 2 and a 4,4 isomer content of 49 wt %

[0053] Iso 2: polymethylenediphenyl diisocyanate having an NCO content of 31.5 wt % and an average functionality of 2.7

[0054] Iso 3: methylenediphenyl diisocyanate having an NCO content of 33.5 wt % and an average functionality of 2 and a 4,4 isomer content of 99 wt %

[0055] Iso 4: Prepolymer of methylenediphenyl diisocyanate, dipropylene glycol and polyether polyol having an average OH number of 250 mg KOH/g, a functionality of 2 and a propylene oxide content based on the total weight of the polyether of 83 wt %. NCO content of 23 wt % and an average functionality of 2

[0056] Iso 5: Mixture of methylenediphenyl diisocyanate and the corresponding carbodiimide having an NCO content of 29.5 wt % and an average functionality of 2.2

TABLE-US-00001 TABLE 1 Refer- Exam- Exam- Exam- Exam- ence 1 ple 1 ple 2 ple 3 ple 4 wt % wt % wt % wt % wt % Polyol 1 67.0 66.1 64.8 64.8 58.0 Polyol 2 15.8 15.8 15.8 15.8 16.0 Polyol 3 10.0 9.9 9.9 9.9 10.0 Polyol 4 1.0 1.0 3.0 3.0 3.0 Polyol 5 6.0 Cat. 1 0.4 0.4 0.4 0.4 0.4 Cat. 2 0.2 0.2 Cat. 3 0.5 0.5 DETDA 1.0 1.0 1.0 1.0 Crosslinker 2.0 2.0 2.0 2.0 2.0 Water 3.1 3.1 3.1 3.1 3.1 Color paste 0.5 Iso 1 50.5 50.5 50.5 Iso 2 32.5 32.5 32.5 15.0 15.0 Iso 3 16.9 16.9 16.9 Iso 4 42.5 42.5 Iso 5 42.5 42.5 Index 100 100 100 100 100

[0057] Table 2 shows the foam quality for the comparative example/the examples 1 to 3 for a foam density of 160 and 145 g/l in each case.

[0058] In table 2:

[0059] Mass is to be understood as meaning the mass of the employed polyurethane reaction mixture

[0060] In terms of foam stability (foam):

[0061] poor is to be understood as meaning that defects are present in the entire component

[0062] average is to be understood as meaning that defects are present at the edges of the component

[0063] good is to be understood as meaning no defects

TABLE-US-00002 TABLE 2 Ref 1 Ref 1 Ex 1 Ex 1 Ex 2 Ex 2 Ex 3 Ex 3 Mass 230 200 230 200 230 200 230 200 Density 160 145 160 145 160 145 160 145 Foam poor poor average poor good good good good

[0064] The tests show that the use of DETDA makes it possible to improve foam quality. Since DETDA likewise shows catalytic activity, the catalyst content can be reduced compared to a standard formulation (Ref. 1) which results in a further improvement in foam quality (Examples 2 and 3).