Hydrophilic copolymers

• US 4,032,599 A
• Filed: 12/09/1974
• Issued: 06/28/1977
• Est. Priority Date: 04/20/1971
• Status: Expired due to Term

• Current Assignee: Neatsimple Limited Broadwalk House
• Original Assignee: Contact Lenses Limited
• Inventors: Mikucki, Wiktor, Cordrey, Philip William
• Primary Examiner(s): Ziegler, J.
• Application Number:
  US05/530,570
• Time in Patent Office: 932 Days
• Field of Search: 260/332, 260/60, 260/80, 260/72, 260/895, 260/882, 260/885, 351/166, 526/259
• US Class Current: 525/404
• CPC Class Codes: C08F 226/06 by a heterocyclic ring containing nitrogen
• CPC Class Codes: C08F 283/06 on to polyethers, polyoxymethylenes or polyacetals C08F283/004 takes precedence
• CPC Class Codes: C08L 39/00 Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a single or double bond to nitrogen or by a heterocyclic ring containing nitrogen; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 51/08 grafted on to macromolecular compounds obtained otherwise than by reactions only involving unsaturated carbon-to-carbon bonds
• CPC Class Codes: G02B 1/043 Contact lenses

Abstract

A hydrophilic copolymer suitable for contact lenses comprises units derived from acrylic acid or methacrylic acid or from a hydrophilic monomer, such as N-vinyl 2-pyrrolidone or 4-vinyl pyridine, containing at least one heterocyclic group as a major hydrophilic unit. The copolymer preferably contains units derived from a hydrophobic monomer, such as methyl methacrylate, and it may also contain units derived from a crosslinking agent and an ethylene oxide-propylene oxide block copolymer. The copolymers are capable of absorbing large quantities of water and are particularly suitable for use in contact with living tissue.

Claims

1. A hydrophilic copolymer obtained by forming a polymerization reaction mixture consisting essentially of (A) N-vinyl-2-pyrrolidone, (B) methyl methacrylate, (C) at least one cross-linking agent having at least two olefinic double bonds in its molecule and (D) an ethylene oxide-propylene oxide block copolymer having a molecular weight in the range of from at least about 1000 to not more than about 6000, the molar ratio of (A):

(B) being from about 6;

1 to about 1;

1, the amount of (C) being from about 0.2% to about 5% by weight based on the weight of (A) plus (B), and the amount of (D) being from about 0.25% to not more than 10% by weight based on the sum of the weights of (A) plus (B) plus (C), polymerizing said polymerization reaction mixture at a temperature of from 35°

to 50°

C. until the monomers have gelled and then raising the temperature to 50°

to 60°

C. and completing the polymerization at the latter temperature and thereby obtaining the hydrophilic copolymer.

2. A hydrophilic copolymer according to claim 1, in which the molar ratio of (A):

(B) is from about 4;

1 to about 1;

1.

3. A hydrophilic copolymer according to claim 2, in which (C) is allyl methacrylate.

4. A hydrophilic copolymer according to claim 3, in which (D) is present in an amount of not more than about 5% by weight based on the weight of (A) plus (B) plus (C).

5. A hydrophilic copolymer according to claim 4, in which (D) has a molecular weight in the range 1,500 to 5,000.

6. A hydrophilic copolymer according to claim 5, in which (D) has a molecular weight of from about 3,000 to about 4,000.

7. A hydrophilic copolymer according to claim 6, in which the amount of (D) is from about 0.5% to about 3%, based on the total weight of (A) plus (B) plus (C).

8. A hydrophilic copolymer according to claim 2, in which (C) is allyl methacrylate, in an amount of not more than 2% by weight of (A) plus (B).

9. A contact lens made from the hydrophilic copolymer claimed in claim 7.

10. A hydrophilic copolymer according to claim 1 in which the polymerizing step is carried out by adding to the polymerization reaction mixture from 0.01% to 0.10% by weight, based on the weight of (A) plus (B) plus (C), of a polymerization initiator, then polymerizing the polymerization reaction mixture under an inert gas atmosphere, or in vacuo, until polymerization is completed.

11. A hydrophilic copolymer according to claim 1, in which (C) is selected from the group consisting of allyl methacrylate, divinyl benzene, ethylene glycol dimethacrylate and diethylene glycol bis(allyl carbonate).