Copolymer for soft contact lens, its preparation and soft contact lens made thereof
AssigneeToyo Contact Lens Co., Ltd.
InventorsKyoichi Tanaka, Kouzou Takahashi, Mitsuhiro Kanada, Shinji Kanome, Tatsutoshi Nakajima
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Abstract
A copolymer suitable for use as soft contact lenses, comprising a polymerization product of (a) at least one monomer selected from methyldi(trimethylsiloxy)sylylpropylglycerol methacrylate and methyldi(trimethylsiloxy)sylylpropylglycerolethyl methacrylate, (b) a hydrophilic monomer and (c) a cross-linking agent having at least two copolymerizable functional groups. Soft contact lens made of the above copolymer has excellent oxygen permeability in spite of low water content and can be comfortably worn continuously for a long term without a foreign body sensation and pain.
Claims12
A polymerization product of
- (a) 15 to 50% of at least one monomer selected from the group consisting of methyldi(trimethylsiloxy)sylylpropylglycerol methacrylate having the following formula ##STR3## and methyldi(trimethylsiloxy)sylylpropylglycerolethyl methacrylate having the following formula ##STR4## (b) 50 to 85% of at least one hydrophilic monomer selected from the group consisting of ethylene glycol monomethacrylate, diethylene glycol monomethacrylate, triethylene glycol monomethacrylate, N-vinyl pyrrolidone and dimethyl acrylamide, and
- (c) 0.3 to 2.0% of at least one cross-linking agent having at least two copolymerizable functional groups selected from the group consisting of ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, allyl methacrylate, divinyl benzene, diallyl phthalate and trimethylolpropane trimethacrylate, said % of (a), (b) and (c) being % by weight based on the total weight of (a), (b) and (c).
A process for preparing a copolymer which comprises bulk-polymerizing
- (a) 15 to 50% of at least one monomer selected from the group consisting of methyldi(trimethylsiloxy)sylylpropylglycerol methacrylate having the following formula ##STR5## and methyldi(trimethylsiloxy)sylylpropylglycerolethyl methacrylate having the following formula ##STR6## (b) 50 to 85% of a hydrophilic monomer, and (c) 0.3 to 2.0% of a cross-linking agent having at least two copolymerizable functional groups,
- in the presence of 0.05 to 0.5 part by weight, per 100 parts by weight of the mixture of (a), (b) and (c), of a free radical polymerization initiator,
- said % of (a), (b) and (c) being % by weight based on the total weight of (a), (b) and (c).
A contact lens made of a copolymer consisting essentially of
- (a) 15 to 50% by weight of units of at least one monomer selected from the group consisting of methyldi(trimethylsiloxy)sylylpropylglycerol methacrylate having the following formula ##STR7## and methyldi(trimethylsiloxy)sylylpropylglycerolethyl methacrylate having the following formula ##STR8## (b) 50 to 85% by weight of hydrophilic monomer units, and (c) 0.3 to 2.0% by weight of units of a cross-linking agent having at least two copolymerizable functional groups.
Dependencies are inferred from the claim text.