Advanced bonding agent
The invention provides a bonding agent particularly suited for bonding metal to castable polyurethane, polyesters and or polyamides.
1 . A bonding agent for bonding castable polyurethane and/or polyamides comprising:
(1) a phenolic resol resin having the following characteristics:
viscosity at 20° C. of 4000±500 mPa·s;
non-volatile components at 135° C. of 79±2%; content of free formaldehyde of maximum 5%; and specific gravity at 20° C. of 1.26 g/cm 3 ;
(2) polyvinylbutyral (PVB); and
(3) a solvent or solvent mixture that is capable of solvating ingredients (1) and (2), while being sufficiently volatile to be removed at atmospheric pressure.
2 . The bonding agent according to claim 1 , wherein the solvent or solvent mixture has a vapor pressure of at least 5 hPa at 20° C.
3 . The bonding agent of claim 1 wherein the phenolic resol resin is present at 5 to 20 wt %, based on a total weight of the bonding agent.
4 . The bonding agent of claim 1 wherein the phenolic resol resin is present at 7 to 15 wt %, based on a total weight of the bonding agent.
5 . The bonding agent of claim 4 wherein the phenolic resol resin is present at 11-12 wt %, based on a total weight of the bonding agent.
6 . The bonding agent of claim 1 wherein the PVB has the following structure:
where the polyvinyl acetate (l) content is 1-8 wt %, the polyvinyl alcohol (m) content is 11-27 wt % and the acetal (p) content is 65-88 wt %, based on a total weight of the PVB.
7 . The bonding agent of claim 6 , wherein the acetal (p) has the following structure:
8 . The bonding agent of claim 6 wherein the PVB has a polyvinyl alcohol (m) content of 12-16 wt % and a polyvinyl acetate (l) content of 1-4 wt %, wherein the weight percentages are based on a total weight of the PVB.
9 . The bonding agent of claim 1 wherein the PVB has a content of polyvinyl alcohol of 11-16 wt %, a polyvinyl acetate content of 1-6 wt %, and an acetal content of 82-88 wt %, wherein the weight percentages are based on a total weight of the PVB.
10 . The bonding agent of claim 1 wherein the polyvinylbutyral has a non-volatile content of greater than or equal to 97.5 wt %, a polyvinyl alcohol content of 12-16 wt % and a polyvinyl acetate content of 1-4 wt %, an acetal content of 82-88 wt %, a dynamic viscosity in a 10% ethanol solution at 20° C. of 120-280, a glass transition temperature, determined by DSC, of 65° C., a water up-take after 24 hours water immersion at 20° C. of 3-5 wt %, and a bulk density of 210 g/L, wherein the weight percentages are based on a total weight of the PVB.
11 . The bonding agent of claim 1 wherein the solvent is a mixture of ketones having C 1-6 alkyl groups, with C 1-5 aliphatic alcohols, and mono- and/or di-C 1-3 -alkyl benzenes.
12 . The bonding agent of claim 1 wherein the solvent mixture comprises 2-10 wt % ketones having C 1-6 alkyl groups, mixed with 50-90 wt % C 1-5 aliphatic alcohols, and 5-20 wt % mono- and/or di-C 1-3 -alkyl benzenes, wherein the weight percentages are based on a total weight of the solvent mixture.
13 . The bonding agent of claim 1 wherein the solvent mixture comprises methyl isobutyl ketone, an alkyl benzene selected from the group consisting of xylenes, toluene and ethyl benzene, and a C 1-4 aliphatic alcohol.
14 . The bonding agent of claim 1 wherein the solvent mixture is a mixture of methyl isobutyl ketone, xylene and iso-propanol.
15 . The bonding agent of claim 1 wherein the solvent mixture comprises 2-10 wt % methyl isobutyl ketone, 5-20 wt % xylene and 50-90 wt % iso-propanol, based on the total weight of a solvent mixture.
16 . The bonding agent of claim 1 wherein the solvent mixture is 5.9 wt % methyl isobutyl ketone, 13.61 wt % xylene, and 80.47 wt % iso-propanol, based on a total weight of the solvent mixture.