摘要:
A solid polymeric latent initiator which is a dehydrated aqueous emulsion polymer of a monomer having an ethylenically unsaturated group and an organic salt group, the salt group being a product of an acid and a base, wherein either the acid or the base or the acid and the base are initiators capable of opening a strained heterocyclic ring system, provides rapid cure-on-demand one-part adhesives with improved shelf stability.
摘要:
An adduct of a monoahl, e.g., a monohydroxyl polyalkylene oxide, and an active ethylenically unsaturated isocyanate, e.g., 2-isocyanatoethyl methacrylate, is usefully employed in the preparation of stable copolymer dispersions of the type used in the production of polyurethane foams and polyurethane elastomers.The copolymer dispersion is prepared by addition copolymerization of (1) the adduct with (2) ethylenically unsaturated monomer(s), e.g., styrene or mixture thereof with acrylonitrile, while (1) and (2) are dispersed or dissolved in an excess of an active hydrogen polyfunctional compound.
摘要:
Vinylized epoxy resins, such as vinyl ester resins, comprise polymerizable ethylenic unsaturation and an in situ polymerized polymer, such as a polyalkyl acrylate. The vinylized epoxy resins can form stable dispersions and are useful in thermoset applications.
摘要:
Dispersions of polymers and optional dispersion stabilizers in a polyepoxide resin continuous phase is characterized in that the dispersion remains stable above 60.degree. C. The compositions are curable and are useful as coatings, in preparing laminates and reinforced plastics, and as adhesives. The compositions exhibit properties which are superior to compositions containing reactive liquid polymers.
摘要:
A low viscosity copolymer polyahl dispersion is prepared by polymerizing polymer particles in a polyahl medium, to a first solids concentration and thereafter diluting the dispersion to a second lower solids concentration. The resulting diluted dispersion has a lower viscosity than if the dispersion were prepared directly at the lower solids level. The invention has particular advantage when used with "all acrylonitrile" dispersions. The copolymer polyahl dispersions are useful in the manufacture of urethane and isocyanurate foams.
摘要:
In one embodiment the invention is An adhesive composition comprising a) a polymer having a flexible backbone and a reactive moiety capable of cross-linking, b) a particle comprising an active agent encapsulated in an encapsulating agent wherein the active agent comprises a catalyst for cross-linking of the reactive moiety, a curing agent for the reactive moiety, an accelerator for the curing reaction or a mixture thereof; and the encapsulating agent comprises a side chain crystallizable polymer wherein the active agent is not substantially extractable from the particle at ambient conditions in a first extraction after particle formation.
摘要:
The present invention is a one-part adhesive composition comprising:A) an isocyanate functional polyurethane prepolymer;B) a catalyst capable of catalyzing the reaction of isocyanate moieties with an isocyanate reactive compound;C) particles comprising a curing agent for an isocyanate functional. polyurethane prepolymer encapsulated within a coating material;wherein the prepolymer has a free isocyanate content of from about 0.8 to about 2.2 percent. In another embodiment the invention is a process for bonding two substrates together which comprises rupturing the encapsulated curing agent particles so as to contact the curing agent with the prepolymer in the adhesive composition, contacting the adhesive composition of the invention with at least one of the substrates and contacting the substrates together along the portion of the substrate(s) to which the adhesive has been applied before the adhesive applied cures and allowing the adhesive to cure and bond the substrates together.
摘要:
Dispersions of siloxane polymers and optional dispersion stabilizers in a polyepoxide resin continuous phase are characterized in that the siloxane polymer is grafted to the polyepoxide resin, and the dispersions remain stable. The compositions are curable and are useful as coatings, in preparing laminates and reinforced plastics, and as adhesives.
摘要:
Vinylized epoxy resins, such as vinyl ester resins, comprise polymerizable ethylenic unsaturation and an in situ polymerized polymer, such as a polyalkyl acrylate. The vinylized epoxy resins can form stable dispersions and are useful in thermoset applications.
摘要:
The invention is an encapsulated active agent comprising an active agent encapsulated in a crystallizable or thermoplastic polymer wherein the particle size of the encapsulated active agent is 3,000 microns or less wherein the active agent is not significantly extractable from the particles under ambient conditions. In another embodiment the invention is a process for preparing an encapsulated agent which comprises a) contacting an active agent with a crystallizable or thermoplastic polymer wherein the polymer is molten and the active agent in not volatile under the contacting conditions; b) forming particles of about 3000 microns or less; and c) exposing the particles to conditions such that the portion of the particle at and near the surface undergoes rapid solidification. The encapsulated active agents of the invention do not require washing in order for them to be stable in curable compositions. These encapsulated active agents can be designed to release the active agent at a desired temperature. The encapsulated agents of the invention demonstrate excellent stability at ambient temperatures and exhibit relatively rapid reactivity upon release of the active agent. Furthermore, the presence of the encapsulating agent does not result in deterioration of adhesive or elastomer properties of a cured composition after preparation.