US 5,629,365 AGranted

UV-absorbing polymer latex

AssigneeMonsanto Company

InventorHomaune A. Razavi

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Abstract

Aqueous latices adapted to forming visible light transparent, coherent polymeric films, e.g. in laminates, as protective coatings or as adhesives, comprising colloidal particles of a UV-absorbing polymer less than 5 micrometers in diameter. Useful UV-absorbing polymer include homopolymers and copolymers of vinyl-functionalized monomer of benzotriazole or benzophenone and mixtures with plasticizer and/or coalescing agent. Plasticizer and coalescing agents are useful for providing polymer with reduced glass transition temperature to facilitate coalescence of polymer particles into coherent films. Useful additives for the latices of this invention include wetting agents, surfactants, and crosslinking agents, anti-oxidants and radical scavengers. The latices of this invention are particularly useful in providing clear, thin coatings on windows, tags, labels, flooring, tents, awnings, containers and other UV-susceptible substrates.

Claims27

Dependent claims

An aqueous latex comprising colloidal particles of a UV-absorbing polymer dispersed in a substantially aqueous medium, wherein said particles are less than 5 micrometers in diameter, and wherein said polymer is selected from the group consisting of:

(i) homopolymers of vinyl-functionalized monomer of benzotriazole or benzophenone,
(ii) copolymers of vinyl-functionalized monomer of benzotriazole or benzophenone and at least one other vinyl monomer,
(iii) mixtures of said homopolymers or copolymers, and plasticizer therefor,
(iv) mixtures of said homopolymers or copolymers, and coalescing agent therefor, and
(v) mixtures of said homopolymers or copolymers, and plasticizer and coalescing agent therefor;
wherein said coalescing agent comprises a volatile solvent for said polymer added in an amount to swell the polymer and thereby reduce the glass transition temperature of the polymer in the latex to less than 50.degree. C.;
and wherein said latex contains a cross linking agent added to the latex after formation of the polymer and one or more of the following additives:
(a) a wetting agent in an amount sufficient to provide said latex with a surface tension of less than 45 dynes/cm.sup.2, wherein said wetting agent is selected from the group consisting of (i) volatile C.sub.2 to C.sub.6 alkyl alcohols, and (ii) non-volatile nonionic and anionic surfactant;
(b) a thickening agent in an amount sufficient to provide the latex with a viscosity greater than 40 centipoises when measured at 25.degree. C. with a Brookfield No. 1 spindle at 5 rpm;
(c) an anti-oxidant;
and
(d) radical scavenger;
such that the latex forms, upon curing, visible light transparent, crosslinked, coherent polymeric films.

10 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/360,828Filed 21 Dec 1994 · continuation in part
Priority: 23 Jun 1992
Granted: 13 May 1997
Term ends: Not estimatedThe source records don’t support an estimate.

Classification3 codes

C09D 133/062
Of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical: copolymers with…
C09D 5/32
Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced ; Filling pastes:…
C09D
Coating compositions