Random block copolymers

• US 7,241,845 B2
• Filed: 03/22/2004
• Issued: 07/10/2007
• Est. Priority Date: 04/01/1993
• Status: Expired due to Term

• Current Assignee: Ocutec Ltd
• Original Assignee: Ocutec Ltd
• Inventors: Graham, Neil Bonnette, Moran, Christopher Raymond
• Primary Examiner(s): Lipman; Bernard
• Application Number:
  US10/805,494
• Publication Number:
  US 20040198901A1
• Time in Patent Office: 1,205 Days
• Field of Search: 525/403, 528/76
• US Class Current: 525/403
• CPC Class Codes: A61K 47/34 Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polyesters, polyamino acids, polysiloxanes, polyphosphazines, copolymers of polyalkylene glycol or poloxamers A61K47/10 takes precedence
• CPC Class Codes: C08G 18/4808 Mixtures of two or more polyetherdiols
• CPC Class Codes: C08G 18/6685 with compounds of group C08G18/3225 or polyamines of C08G18/38
• CPC Class Codes: C08G 2210/00 Compositions for preparing hydrogels
• CPC Class Codes: C08G 65/33348 containing isocyanate group
• CPC Class Codes: C08G 81/00 Macromolecular compounds obtained by interreacting polymers in the absence of monomers, e.g. block polymers involving only carbon-to-carbon unsaturated bond reactions C08F299/00 ; polyester-amides C08G69/44; polyester-imides C08G73/16; polyamides-imides C08G73/14; block- or graft polymers containing polysiloxane sequences C08G77/42
• CPC Class Codes: C08G 81/024 Block or graft polymers containing sequences of polymers of C08C or C08F and of polymers of C08G

Abstract

A linear random block copolymer comprising segments of polyethylene oxide and a relatively more hydrophobic polymer, e.g. polypropylene oxide connected by hydrophobic segments containing urethane and urea groups formed from the reaction of a di-isocyanate and a diamine, wherein the diamine comprises less than 2% by weight of the total weight of the reactants used in the preparation of the copolymer.

Claims

1. An organic solvent-soluble linear random block copolymer hydrogel containing discrete polymeric first and second segments, the first segments comprising hydrophilic mainly polyethylene oxide segments —

(CH₂CH₂O)_n—

, the second segments being of relatively more hydrophobic character than the first segments, wherein the second polymer segments are disposed randomly in the polymer chain as discrete blocks, successive segments being connected through urethane —

NHCOO—

linkages to hydrophobic connecting segments, a minor proportion of which also containing urea —

NHCONH—

groups, which urea groups are present as units of formula

—

NHCONH—

R—

NHCONH—

wherein R represents a hydrocarbyl group, all of said first, second, and connecting segments being randomly distributed throughout the copolymer, the proportion of urea groups comprising from 0.1 to 5.0% by weight of the copolymer.

2. A copolymer hydrogel according to claim 1, in which the hydrophilic segments comprise mainly polyethylene oxide (PEO) residues and a minor amount of an additional component derived from other alkylene oxides, epihalohydrins, cyclic mono or poly ethers including oxetane, tetrahydrofuran, dihydrofuran, dihydropyran, dioxolane and trioxane and N[epoxy substituted] heterocyclic compounds such as N-[2,3-epoxy-propyl]-pyrolidone.

3. A copolymer hydrogel according to claim 2, in which the hydrophilic segment contains up to 25% by weight of groups derived from propylene oxide, 1,2, epoxybutane or 2,3, epoxybutane.

4. A copolymer hydrogel according to claim 1 in which the second segments are derived from a polymer which, together with the polyethylene oxide (PEO), will form a homogeneous melt or solvent solution of the component polymers from which the copolymer product can be formed by a polymerisation reaction.

5. A copolymer hydrogel according to claim 1, in which the second segments comprise polypropylene oxide (PPO) segments —

(CH(CH₃)CH₂O—

)_n—

.

6. A copolymer hydrogel according to claim 1 in which the relative proportions of the hydrophilic PEO segments and the second segments, are from 5 to 90% PEO and 55 to 5% of the second segments.

7. A copolymer hydrogel according to claim 1 in which the relative proportions of the hydrophilic PEO segments and the second segments are from 30 to 60% PEO and from 45 to 15% of the second segments.

8. A copolymer hydrogel according to claim 1, wherein the polyethylene oxide segments are comprised of homopolymeric polyethylene oxide having a number average molecular weight of from 1,000 to 20,000.

9. A copolymer hydrogel according to claim 5, wherein the polypropylene oxide segments are comprised of homopolymeric polypropylene oxide having a number average molecular weight of from 250 to 6,000.

10. A copolymer hydrogel according to claim 1, in which the more hydrophobic second segments are derived from a hydroxy or amine terminated polyol derived from polytetramethylene oxide, polyisobutylene, polyethylene adipate, polytetramethylene adipate, polycaprolactone, polybutadiene and hydroxybutyl terminated polydimethylsiloxane.

11. A copolymer hydrogel according to claim 1, wherein the toughness of the copolymers in the dry state as calculated by measuring the area under the curve of the stress-strain isotherm is retained to at least 15% when the copolymers are swollen.

12. A copolymer hydrogel according to claim 11, wherein the energy to break of the swollen copolymer is at least 40% of that of the copolymer in the dry state.

13. A copolymer hydrogel according to claim 1 4comprising units of the formula

X—

OOCNH—

R—

NHCONH—

R′

—

NHCONH—

R—

NHCOO—

Y

wherein X represents a polyethylene oxide segment, Y represents a second segment and R and R′

which may be the same or different represent hydrocarbyl groups comprising from 2 to 20 carbon atoms.

14. A copolymer hydrogel according to claim 13, also comprising a smaller proportion of units of the formula

X—

NHCONH—

(R″

)_a—

NHCONH—

Y

wherein X represents a hydrophilic polyethylene oxide segment, Y represents a second segment, a is 0 or 1 and R″

represents a hydrocarbyl group comprising from 2 to 20 carbon atoms.

15. A copolymer hydrogel according to claim 13, wherein R and R″

represent an aliphatic group and R′

represents an aromatic group.

16. A copolymer hydrogel according to claim 15, wherein R′

is 1,2-cyclohexylene or a 4,4′

-diphenylmethane group.

17. A copolymer hydrogel according to claim 15 wherein R and R″

are hexamethylene, isophorone or 4,4′

-dicyclohexylmethane groups.

18. A copolymer hydrogel according to claim 14, wherein R″

represents a group having the formula

[R—

X—

R]-n or [R—

Y—

R]-m

wherein R represents a hydrocarbyl group having from 2 to 20 carbon atoms, X represents a polyethylene oxide group, Y represents a polypropylene oxide group and n and m being an integer having a value of at least 1, n and m being the same or different.

19. A copolymer hydrogel according to claim 18, wherein R represents a hexamethylene, isophorone or 4,4′

-dicyclohexylmethane group.

20. Shaped articles prepared from a copolymer according to claim 1.

21. Articles coated with a copolymer according to claim 1.