Plastic molds and methods of producing same

Claim 1

A method of producing a plastic mold comprising the steps of: forming a layer of a photocurable resin composition containing 100 weight parts of a photocurable liquid, an effective amount of photoinitiator, 50-400 weight parts of a filler and less than 5 weight parts of salt of phosphoric acid ester per 100 weight parts of said filler; said photocurable liquid consisting of unsaturated urethane having a total of three or more methacryloyl groups and acryloyl groups as radical polymerizable groups per molecule and an average molecular weight per radical polymerizable group of 150-250 and a vinyl monomer which is N-(meth)acrylate morpholine or a mixture of N-(meth)acrylate morpholine and di-ol di(meth)acrylate at weight ratio of (unsaturated urethane)/(vinyl monomer)=80/20-30/70; said filler being a mixture of inorganic fine particles and inorganic whiskers of average fiber length 1-70 μm both surface-treated with (meth)acryloyl modified silane or vinyl modified silane; said salt of phosphoric acid ester being shown by Formula (1) given below: ##STR2## where R is a hydrocarbon group with 1-6 carbon atoms, Y is a residual group obtained by removing hydroxyl groups of polyether di-ol, B is monoamine base and m and n are each 1 or 2 such that m+n=3; exposing said layer to actinic radiation to at least partially photocure said layer; forming another layer of said photocurable resin composition on said at least partially photocured layer; exposing said another layer to actinic radiation and thereby photocuring said another layer at least partially; repeating the steps of forming another layer and exposing said another layer and thereby obtaining a photocured layered structure having a glass transition temperature of 70°-120° C.; and subjecting said photocured layered structure to a post-cure process at a post-cure temperature which is higher than said glass transition temperature by 30°-100° C. thereby producing a plastic mold.

Claim 2

A method of producing a plastic mold comprising the steps of: forming a layer of a photocurable resin composition containing 100 weight parts of a photocurable liquid, an effective amount of photoinitiator, 50-400 weight parts of a filler and less than 5 weight parts of salt of phosphoric acid ester per 100 weight parts of said filler; said photocurable liquid consisting of unsaturated urethane having a total of three or more methacryloyl groups and acryloyl groups as radical polymerizable groups per molecule and an average molecular weight per radical polymerizable group of 150-250 and a vinyl monomer which is N-(meth)acrylate morpholine or a mixture of N-(meth)acrylate morpholine and di-ol di(meth)acrylate at weight ratio of (unsaturated urethane)/(vinyl monomer)=80/20-30/70; said filler being a mixture of inorganic fine particles and inorganic whiskers of average fiber length 1-70 μm both surface-treated with (meth)acryloyl modified silane or vinyl modified silane; said salt of phosphoric acid ester being shown by Formula (1) given below: ##STR2## where R is a hydrocarbon group with 1-6 carbon atoms, Y is a residual group obtained by removing hydroxyl groups of polyether di-ol, B is monoamine base and m and n are each 1 or 2 such that m+n=3; exposing said layer to actinic radiation to at least partially photocure said layer; forming another layer of said photocurable resin composition on said at least partially photocured layer; exposing said another layer to actinic radiation and thereby photocuring said another layer at least partially; repeating the steps of forming another layer and exposing said another layer and thereby obtaining a photocured layered structure having a glass transition temperature of 70°-120° C.; and subjecting said photocured layered structure to a post-cure process at a post-cure temperature which is higher than said glass transition temperature by 30°-100° C. thereby producing a plastic mold.