Polymeric mixtures and process therefor
First Claim
1. A process for preparing a tough polymeric mixture comprising the steps of:
- a) providing admixture I or IIwhereinadmixture I comprises 5 to 45 weight percent of a first monomer and a photoinitiator therefor, said first monomer being at least one free-radically polymerizable monomer, and 95 to 55 weight percent of a second monomer and a photoinitiator therefor, said second monomer being at least one set of polyurethane precursors selected from the group consisting of one or more diisocyanates and polyisocyanates, and one or more monomers bearing at least two isocyanate-reactive groups, andadmixture II comprises 5 to 45 weight percent of a first monomer and a photoinitiator therefor, said first monomer being at least one set of polyurethane precursors as defined above, and 95 to 55 weight percent of a second monomer and a photoinitiatro therfor, said second monmer being at least one free-radically polymerizable monomer, andb) exposing sequentially said admixture I or II to first and second actinic radiations of wavelength ranges centered around λ
1 and λ
2, respectively, wherein said first actinic radiation activates said photinitiatro of said first monomer without substantially activating said photoinitiator for said second monomer, and wherein said second actinic radiation activates said photinitiator for said second monomer, andwherein λ
1 and λ
2 differ from each other by at least 30 nm, andwherein the monomer present in lesser amount is exposed to said first actinic radiation centered around λ
1 and wherein said monomer present in greater amount is exposed to said second and subsequent actinic radiation centered around λ
2,wherein the actinic radiation centered around λ
1 does not substantially polymerize the second monomer, andwherein the area under a stress-strain curve as determined by ASTM D638-89 for said polymeric mixture is at least 10 percent greater when said precursor monomers are cured by said sequential photoinitiation process compared to that are for the mixture when cured by a single photostage curing process.
1 Assignment
0 Petitions
Accused Products
Abstract
A tough polymeric mixture comprises the polymerized product of admixture I or II, wherein
admixture I comprises 5 to 45 weight percent of a first monomer and a photoinitiator therefor, said first monomer being at least one free-radically polymerizable monomer, and 95 to 55 weight percent of a second monomer and a photoinitiator therefor, said second monomer being at least one set of polyurethane precursors, and
admixture II comprises 5 to 45 weight percent of a first monomer and a photoinitiator therefor, said first monomer being at least one set of polyurethane precursors, and 95 to 55 weight percent of a second monomer and a photoinitiator therefor, said second monomer being at least one free-radically polymerizable monomer,
said polymeric mixture having been prepared by a process involving two sequential actinic radiations of wavelengths ranges centered around λ1 and λ2, respectively, wherein λ1 and λ2 differ from each other by at least 30 nm, and
wherein the actinic radiation centered λ1 does not substantialy polymerize the second monomer, and
wherein the area under a stress-strain curve as determined by ASTM D638-89 for said polymeric mixture is at least 10 percent greater, preferably 20 percent greater, and more preferably at least 50 percent greater when said precursor monomers are cured by said sequential photoinitiation process compared to when the same mixture is cured by a single photostage cure.
60 Citations
20 Claims
-
1. A process for preparing a tough polymeric mixture comprising the steps of:
-
a) providing admixture I or II wherein admixture I comprises 5 to 45 weight percent of a first monomer and a photoinitiator therefor, said first monomer being at least one free-radically polymerizable monomer, and 95 to 55 weight percent of a second monomer and a photoinitiator therefor, said second monomer being at least one set of polyurethane precursors selected from the group consisting of one or more diisocyanates and polyisocyanates, and one or more monomers bearing at least two isocyanate-reactive groups, and admixture II comprises 5 to 45 weight percent of a first monomer and a photoinitiator therefor, said first monomer being at least one set of polyurethane precursors as defined above, and 95 to 55 weight percent of a second monomer and a photoinitiatro therfor, said second monmer being at least one free-radically polymerizable monomer, and b) exposing sequentially said admixture I or II to first and second actinic radiations of wavelength ranges centered around λ
1 and λ
2, respectively, wherein said first actinic radiation activates said photinitiatro of said first monomer without substantially activating said photoinitiator for said second monomer, and wherein said second actinic radiation activates said photinitiator for said second monomer, andwherein λ
1 and λ
2 differ from each other by at least 30 nm, andwherein the monomer present in lesser amount is exposed to said first actinic radiation centered around λ
1 and wherein said monomer present in greater amount is exposed to said second and subsequent actinic radiation centered around λ
2,wherein the actinic radiation centered around λ
1 does not substantially polymerize the second monomer, andwherein the area under a stress-strain curve as determined by ASTM D638-89 for said polymeric mixture is at least 10 percent greater when said precursor monomers are cured by said sequential photoinitiation process compared to that are for the mixture when cured by a single photostage curing process. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
-
Specification