Aqueous resorcinol-formaldehyde-latex dispersions, adhesion-improved fibres, processes for production thereof and use thereof
The present invention relates to aqueous resorcinol-formaldehyde-latex dispersions comprising at least one carbodiimide based on compounds of the formula (I) R′—(—N═C═N—R—) m —R″ (I), where, m is an integer from 1 to 500, R=C 1 -C 18 -alkylene, C 5 -C 18 -cycloalkylene-, arylene and/or C 7 -C 12 -aralkylene, R′=R—NCO, R—NHCONHR 1 , R—NHCONR 1 R 2 , R—NHCOOR 3 or R—NHCO—R 5 and R″=—NCO, —NHCONHR 1 , —NHCONR 1 R 2 , —NHCO—R 5 or —NHCOOR 3 , where R 1 and R 2 in R′ are mutually independently identical or different and are a C 1 -C 6 -alkyl moiety, C 6 -C 10 -cycloalkyl moiety or C 7 -C 12 -aralkyl moiety, and R 3 is as defined for R 1 or is a polyester moiety or a polyamide moiety or —(CH 2 ) l —(O—(CH 2 ) k —O) g —R 4 , —C 8 H 4 (OH) or —C 8 H 3 (OH)—((CH 2 ) h —C 6 H 4 (OH)) y and R 5 =epoxide, phenol, oxime, resorcinol, polyethylene glycols and/or lactam, preferably caprolactam, where l=from 1 to 3, k=from 1 to 3, g=from 0 to 12, h=from 1 to 2 and y=from 1 to 50, and R 4 =H or C 1 -C 4 -alkyl.
1. Aqueous resorcinol-formaldehyde-latex dispersion comprising at least one carbodiimide based on compounds of the formulas (IIa), (IIb), (III), (IV), and (V) below
where R 5 =epoxide, phenol, oxime, resorcinol, polyethylene glycols and/or lactam,
where R=C 1 -C 18 -alkylene, C 5 -C 18 -cycloalkylene-, arylene and/or C 7 -C 12 -aralkylene and j is identical or different within the molecule and is from 1 to 5, and where p=from 0 to 500,
where x=from 1 to 500, and/or
where n=from 1 to 20;
and R 3 =a polyester moiety or polyamide moiety, or —(CH 2 ) l —(O—(CH 2 ) k —O g )—R 4 ,
where l=from 1-3, k=from 1-3, g=from 0-12, and
R 4 =H or C 4 -C 4 -alkyl.
2. Aqueous resorcinol-formaldehyde-latex dispersion according to claim 1 , characterized in that the resorcinol-formaldehyde-latex dispersion involves a dispersion of the individual components resorcinol and formaldehyde, and/or formaldehyde together with a precondensate made of resorcinol and formaldehyde and of one or more of the latex dispersions selected from the following group consisting of carboxylated styrene-butadiene copolymers (XSBR latex), nitrile-butadiene copolymers (NBR latex), polychloroprene (CR latex), pyridine-styrene-butadiene copolymers (PSBR latex), acrylate-only copolymers, styrene-acrylate copolymers (acrylate latex), and styrene-butadiene-vinylpyridine copolymer latices.
3. Process for producing aqueous resorcinol-formaldehyde-latex dispersions according to claim 1 , characterized in that at least one carbodiimide according to claim 1 is incorporated by stirring into the resorcinol-formaldehyde-latex dispersion.
4. Adhesive formulation, comprising an aqueous resorcinol-formaldehyde-latex dispersion according to claim 1 and also at least one activator.
5. Adhesive formulation according to claim 4 , characterized in that the activator is at least one epoxide.
6. Process for improving the adhesion of reinforcement fibres to crosslinked rubber and/or elastomers, characterized in that
introducing the fibres into an adhesive formulation according to claim 4 and drying the resultant mixture, or
treating the fibres in one or more steps with one or more of the constituents of the adhesive formulation according to claim 4 .
7. Process for improving the adhesion of reinforcement fibres to crosslinked rubbers or elastomers, comprising introducing preactivated fibres into an aqueous resorcinol-formaldehyde-latex dispersion according to claim 1 and drying the resultant mixture.
8. Adhesion-improved fibres, obtainable by contacting activator-pretreated fibres with at least one aqueous resorcinol-formaldehyde-latex dispersion according to claim 1 , or by contacting a non-pretreated fibre with at least one adhesive formulation according to claim 4 , and subsequently drying (setting) at temperatures of from 180 to 260° C.
9. Process according to claim 6 , wherein the improved adhesion of reinforcement fibres to crosslinked rubber and/or elastomers is used in tyres, drive belts, conveyor belts and/or hoses.