AN AQUEOUS TWO-COMPONENT ADHESIVE

Abstract

The invention relates to an aqueous two-component adhesive and use thereof, in particular to the use for laminating a rigid substrate and a plastic film, a laminated product comprising the adhesive, and a method for producing a laminated product. The aqueous two-component adhesive comprises component A and component B, the component A comprising more than 50% by weight and not more than 99% by weight of an aqueous polyurethane dispersion; the B component comprising 1% by weight to 16% by weight of water-dispersible modified polyisocyanate based on hexamethylene diisocyanate, the above weight percentage based on the amount of the adhesive being 100% by weight; wherein the aqueous polyurethane dispersion comprises polyurethane dispersed therein, the enthalpy of melting of the polyurethane being 26 to 100 J/g, preferably 30 to 100 J/g, particularly preferably 30 to 60 J/g, measured at 20° C. to 100° C. for the first heating curve by DSC according to DIN65467 (1999). The aqueous two-component adhesive has the advantages of safety and environmental protection, excellent performance and low laminating temperature.

Claims

1. An aqueous two-component adhesive, comprising component A and component B, said component A comprising more than 50% by weight and not more than 99% by weight of an aqueous polyurethane dispersion; said component B comprising 1% by weight to 16% by weight of a water-dispersible modified polyisocyanate based on hexamethylene diisocyanate, the above weight percentage based on the amount of the adhesive being 100% by weight; wherein the aqueous polyurethane dispersion comprises polyurethane dispersed therein, the enthalpy of melting of the polyurethane being 26 to 100 J/g, measured at 20° C. to 100° C. for the first heating curve by DSC according to DIN65467 (1999).

2. The adhesive according to claim 1, wherein the polyurethane is obtained by reacting a system comprising an aliphatic polyisocyanate and polybutylene adipate polyol.

3. The adhesive according to claim 2, wherein the aliphatic polyisocyanate is one or more selected from the group comprising hexamethylene diisocyanate and isophorone diisocyanate.

4. The adhesive according to claim 1, wherein the enthalpy of melting of the polyurethane is 30 to 100 J/g, measured at 20° C. to 100° C. for the first heating curve by DSC according to DIN65467 (1999).

5. The adhesive according to claim 1, wherein the amount of the water-dispersible modified polyisocyanate based on hexamethylene diisocyanate is 2% to 15% by weight, based on the amount of the adhesive being 100% by weight.

6. The adhesive according to claim 1, wherein the water-dispersible modified polyisocyanate based on hexamethylene diisocyanate is one or more selected from the group comprising polyether-modified polyisocyanates based on hexamethylene diisocyanate and ionically modified polyisocyanates based on hexamethylene diisocyanate.

7. The adhesive according to claim 1, wherein the component A further comprises an aqueous polymer dispersion different from the aqueous polyurethane dispersion, and the amount of the aqueous polymer dispersion is not more than 48% by weight, based on the amount of the adhesive being 100% by weight.

8. The adhesive according to claim 1, wherein it further comprises an associative polyurethane thickener, and the amount of the thickener is 0.1% by weight to 3.0% by weight, based on the amount of the adhesive being 100% by weight.

9. The adhesive according to claim 1, wherein it further comprises a wetting agent, and the amount of the wetting agent is 0.1% by weight to 1.0% by weight, based on the amount of the adhesive being 100% by weight.

10. A laminated product comprising: a rigid substrate; a plastic film; and a coating formed by curing of the adhesive according to claim 1 applied on at least one surface of the rigid substrate and the plastic film; wherein the rigid substrate and the plastic film are laminated with the adhesive.

11. The laminated product according to claim 10, wherein the rigid substrate is a metal substrate or a metal composite substrate.

12. The laminated product according to claim 11, wherein the metal substrate is a galvanized iron sheet, a galvanized steel sheet, a cold-rolled sheet, a hot-dip galvanized sheet, an electro-galvanized sheet, a zinc-iron alloy sheet or an aluminum alloy sheet.

13. The laminated product according to claim 10, wherein the plastic film is a PVC film, an ASA film, a PET film, a PETG film, an ASA/PVC composite film, a PMMA/PVC composite film, a PVDF/PVC composite film, a PET/PVC composite film or a PETG/PVC composite film.

14. The laminated product according to claim 10, wherein the laminated product is an interior or exterior decoration panel for a building, an encaustic tile for a roof or a housing for a household appliance.

15. A method for producing a laminated product comprising the following steps: i. applying the adhesive according to claim 1 onto at least one surface of a rigid substrate; ii. heating the surface of the rigid substrate coated with the adhesive; and iii. laminating the plastic film and the surface of the rigid substrate coated with the adhesive, and curing to obtain the laminated product.

16. The method according to claim 15, wherein said laminating is carried out at a temperature of the surface of the rigid substrate coated with said adhesive of 100° C. to 180° C.

17. The method according to claim 15, wherein the rigid substrate is a metal substrate or a metal composite substrate.

18. The method according to claim 17, wherein the metal substrate is a galvanized iron sheet, a galvanized steel sheet, a cold-rolled sheet, a hot-dip galvanized sheet, an electro-galvanized sheet, a zinc-iron alloy sheet or an aluminum alloy sheet.

19. The method according to claim 15, wherein the plastic film is a PVC film, an ASA film, a PET film, a PETG film, an ASA/PVC composite film, a PMMA/PVC composite film, a PVDF/PVC composite film, a PET/PVC composite film or a PETG/PVC composite film.

20. The method according to claim 15, wherein the laminated product is an interior or exterior decoration panel for a building, an encaustic tile for a roof or a housing for a household appliance.

21.-22. (canceled)

Description

Examples 1-10 and Comparative Examples 1-6

[0206] In Table 2, the composition and results of sample tests of the adhesives of Examples 1-10 and Comp. 1-6 are listed.

[0207] It can be seen from Table 2 that the samples of laminated products of a rigid substrate and a plastic film obtained from the aqueous two-component adhesive provided by the present invention at a laminating temperature of 150° C. have passed all tests, indicating that the adhesives of the present invention have excellent performance. It can be seen by comparing Comparative Example 1 and Examples 1-10 that the sample obtained from the commercially available solvent-based polyurethane adhesives at a laminating temperature of 150° C. has failed. Only the sample obtained at a laminating temperature of 180° C. can achieve the performance equivalent to that of samples obtained from the adhesives of the present invention. It can be known from Comparative Examples 2 and 3 that the samples obtained by the adhesives fail in the bonding strength test and 100° C. high temperature test, when the enthalpy of melting of the polyurethane in the aqueous polyurethane dispersion of said adhesive is less than 3 J/g. It can be seen from Comparative Example 4 that the samples obtained by the adhesives fail in the bonding strength test, 90° bending test and 100° C. high temperature test, when the curing agent for the adhesives is a dimer based on toluene diisocyanate (TDI). It can be seen from Comparative 5 and 6 that the obtained samples fail in the bonding strength test, 90° bending test and 100° C. high temperature test, when the content of the water-dispersible modified polyisocyanate based on hexamethylene diisocyanate is more than 16% by weight.

[0208] Those skilled in the art will readily understand that the present invention is not limited to the foregoing specific details, and the present invention can be implemented in other specific forms without departing from the spirit or main characteristics of the present invention. The embodiments are therefore to be considered as illustrative and not restrictive in any way, so that the scope of the present invention is indicated by the claims rather than by the foregoing description. Thus, any change should be regarded as belonging to the present invention, as long as it belongs to the meaning and the scope of equivalents of the claims.

TABLE-US-00002 TABLE 2 Adhesive composition and results of sample tests Comp. Comp. Comp. Comp. Comp. Comp. Ex. Ex. Ex. 1 2 3 4 5 6 1 2 3 Component A Commercially 100.0 available solvent-based polyurethane adhesive Dispercoll U 42 99.2 99.2 Dispercoll U 54 99.2 99.2 99.2 Dispercoll U 62 99.2 Dispercoll U 58 Dispercoll U 58/1 Dispercoll U XP 2612 99.2 99.2 BYK-349 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Borchi Gel L 75 N 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Component B Matched curing 5 agent for commercially available solvent-based polyurethane adhesive Desmodur DN 5 22 5 5 Bayhydur 3100 5 22 5 Dispercoll BL XP 2514 12.5 Sample tests Laminating 150 180 150 150 150 150 150 150 150 150 temp./° C. Bonding strengh x √ x x x x x √ √ √ 90° bending x √ √ √ x x x √ √ √ 100° C. high x √ x x x x x √ √ √ temperature Impact resistance √ √ √ √ √ √ √ √ √ √ Salt spray test √ √ √ √ √ √ √ √ √ √ Alternating high √ √ √ √ √ √ √ √ √ √ and low temp. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 4 5 6 7 8 9 10 Component A Commercially available solvent-based polyurethane adhesive Dispercoll U 42 Dispercoll U 54 Dispercoll U 62 99.2 Dispercoll U 58 99.2 99.2 Dispercoll U 58/1 99.2 99.2 Dispercoll U XP 2612 99.2 99.2 BYK-349 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Borchi Gel L 75 N 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Component B Matched curing agent for commercially available solvent-based polyurethane adhesive Desmodur DN 5 5 5 Bayhydur 3100 5 5 5 5 Dispercoll BL XP 2514 Sample tests Laminating 150 150 150 150 150 150 150 temp./° C. Bonding strengh √ √ √ √ √ √ √ 90° bending √ √ √ √ √ √ √ 100° C. high √ √ √ √ √ √ √ temperature Impact resistance √ √ √ √ √ √ √ Salt spray test √ √ √ √ √ √ √ Alternating high √ √ √ √ √ √ √ and low temp.