Dispersion adhesives
The invention relates to formulations of aqueous dispersion adhesives based on aqueous polyurethane or polyurethane-urea dispersions, and to the use of the adhesive formulations for the adhesive bonding of foam substrates by the spray coagulation process. The dispersion comprises as disperse phase at least one polymer which after drying is semicrystalline or crystalline and has a melting temperature in the range from 30 to 80° C. and an enthalpy of fusion of ≥35 J/g. The formulation comprises at least one plasticizer and optionally at least one tackifier resin.
1 . A formulation comprising a mixture of:
I. an aqueous polyurethane or polyurethane-urea dispersion, containing as disperse phase at least one polymer A) which after drying is semicrystalline or crystalline and has a melting temperature in the range from 30 to 80° C. and an enthalpy of fusion of ≥35 J/g, wherein polymer A consists of components:
A(i) at least one crystalline or semicrystalline difunctional polyester polyol having a number-average molecular weight of at least 400 g/mol and a melting temperature of at least 35° C. and a heat of fusion of at least 35 J/g,
A(ii) optionally at least one difunctional polyol component having a number-avenge molecular weight of 62 to 390 g/mol,
A(iii) an isocyanate component selected from the group consisting of hexamethylene diisocyanate (HDI) and 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI), and mixtures thereof,
A(iv) at least one isocyanate-reactive component bearing at least one ionic or potentially ionic group, and
A(v) optionally further isocyanate-reactive components,
II. at least one plasticizer B),
I. optionally at least one tackifier resin C),
wherein the mixture, based on the solids present overall, comprises:
60% to 80% by weight of the at least one polymer A),
20% to 40% by weight of the at least one plasticizer B), and
0% to 10% by weight of the at least one tackifier resin C),
and the amounts by weight of A), B) and C) add up to 100% by weight.
2 . The formulation according to claim 1 , wherein the mixture, based on the solids present overall, comprises:
65% to 80% by weight of the at least one polymer A),
20% to 35% by weight of the at least one plasticizer B), and
0% to 10% by weight of the at least one tackifier resin C),
and the amounts by weight of A), B) and C) add up to 100% by weight.
3 . The formulations of claim 2 , wherein the mixture, based on the solids present overall, comprises:
70%-80% by weight of the at least one polymer A),
20% to 30% by weight of the at least one plasticizer B), and
0% to 10% by weight of the at least one tackifier resin C),
and the amounts by weight of A), B) and C) add up to 100% by weight.
4 . The formulation of claim 1 , wherein the at least one polymer A) which after drying is semicrystalline or crystalline has a melting temperature in the range from 35 to 80° C.
5 . The formulation of claim 4 , wherein the at least one polymer A) which after drying is semicrystalline or crystalline has a melting temperature in the range from 40 to 70° C.
6 . The formulation of claim 5 , wherein the at least one polymer A) which after drying is semicrystalline or crystalline has a melting temperature in the range from 42 to 55° C.
7 . The formulation of claim 1 , wherein the at least one polymer A) which after drying is semicrystalline or crystalline has an enthalpy of fusion of ≥35 J/g.
8 . The formulation of claim 7 , wherein the at least one polymer A) which after drying is semicrystalline or crystalline has an enthalpy of fusion of ≥40 J/g.
9 . The formulation of claim 8 , wherein the at least one polymer A) which after drying is semicrystalline or crystalline has an enthalpy of fusion of ≥45 J/g.
10 . The formulation of claim 1 , wherein the at least one plasticizer B) comprises di(phenoxyethyl) formal and non-volatile esters based on aromatic carboxylic acids, aliphatic carboxylic acids, or fatty acids; or phosphoric, sulfonic or alkylsulfonic, esters.
11 . The formulation of claim 1 , wherein the at least one plasticizer B) comprises at least one compound selected from the group consisting of di(phenoxyethyl) formal, dibutyl terephthalate, alkylsulfonic esters of phenol and esters based on benzoic acid.
12 . A process for adhesively bonding substrates by mixing a formulation of claim 1 with a coagulant in a two-component spray gun, wherein the coagulant is conveyed separately into the two-component spray gun and is mixed in the spray jet and the coagulation of the dispersion in the spray jet takes place on the path to the surface of the first substrate, on impact with said substrate forms a film which is immediately tacky in the still-wet state and in the wet state the second surface is immediately joined, if required with pressure on the substrates towards the adhesive surface.
13 . Substrates adhesively bonded with the formulation of claim 1 , wherein the substrates are composed of foam, wood, paper, leather, textiles, cork, or plastics.
14 . The substrates of claim 13 , wherein the substrates comprise a first substrate that is foam or textiles, adhesively bonded to a second substrate that is foam, wood, or plastic.
15 . The substrates of claim 14 , wherein the first substrate is polyurethane foam or foam rubber.
16 . A mattress or furniture comprising the formulation of claim 1 .