Rim process for the production of elastic moldings

• US 4,218,543 A
• Filed: 01/15/1979
• Issued: 08/19/1980
• Est. Priority Date: 05/21/1976
• Status: Expired due to Term

• Current Assignee: Mobay Chemical Corporation (Bayer AG)
• Original Assignee: Bayer AG
• Inventors: Weber, Christian, Schafer, Hermann
• Primary Examiner(s): Cockeram, H. S.
• Application Number:
  US06/003,573
• Time in Patent Office: 582 Days
• Field of Search: 521/51, 521/912, 521/914, 528/64, 252/182
• US Class Current: 521/51
• CPC Class Codes: C08G 18/3237 aromatic C08G18/3234 takes precedence
• CPC Class Codes: C08G 18/6529 Compounds of group C08G18/3225 or polyamines of C08G18/38
• CPC Class Codes: C08G 2120/00 Compositions for reaction injection moulding processes
• CPC Class Codes: Y10S 264/83 Injection molding of polyolefin-type foam

Abstract

The instant invention relates to a one-step process for the production of elastomeric moldings which have a compact surface by the technique of reaction injection molding, using highly reactive systems of specific polyisocyanates, polyhydroxyl compounds and specific active aromatic polyamines. The instant invention further relates to active hydrogen containing blends useful in preparing elastomeric moldings, said blends comprising polyhydroxyl compounds, and specific active aromatic diamines. The blends herein may also contain catalyst for the reaction between hydroxyl groups and isocyanate groups.

Claims

1. In a process for the production of polyurethane elastomer moldings having a compact surface skin from a reaction mixture by a reaction injection molding process, wherein said reaction mixture comprises the following components:

(a) 4,4'"'"'-diisocyanatodiphenylmethane,polyisocyanates based on 4,4'"'"'-diisocyanatodiphenylmethane or mixtures thereof;

(b) hydroxyl group containing compounds having molecular weights of from 1800 to 12,000;

(c) a chain extender; and

(d) a catalyst for the reaction between hydroxyl groups and isocyanate groups;

the improvement wherein said chain extender is miscible with component (b) in any proportion and is an active aromatic diamine having alkyl groups of from 1 to 3 carbon atoms in the ortho-positions to each amino group, and wherein said components are processed via the one-shot process whereby (a) is mixed simultaneously either with (b), (c), and (d) or with a non-reacted premixture of some or all of (b), (c), and (d) or with a non-reacted premixture of some or all of (b), (c) and (d), with the proviso that at least two of said alkyl substituents contain 2 or 3 carbon atoms.

2. The process of claim 1, wherein the reaction mixture also contains a blowing agent and wherein said moldings are further characterized as having a cellular core.

3. The process of claim 1, wherein said chain extender contains at least one linear alkyl substituent in the ortho-position to a first amino group and two linear alkyl substituents in the ortho-position to a second amino group, and wherein said chain extender is either in liquid form or is dissolved in said hydroxyl group containing compound.

4. The process of claim 1, wherein said chain extender is selected from the group consisting of 1-methyl-3,5-diethyl-2,4-diamino benzene;

1-methyl-3,5-diethyl-2,6-diamino benzene;

1,3,5-triethyl-2,6-diamino benzene;

3,5,3'"'"',5'"'"'-tetraethyl-4,4'"'"'-diaminodiphenyl methane; and

mixtures thereof.

5. The process of claim 4, wherein said chain extender is selected from the group consisting of 1-methyl-3,5-diethyl-2,4-diamino benzene;

1-methyl-3,5-diethyl-2,6-diaminobenzene; and

mixtures thereof.

6. The process of claim 1, wherein

(i) component (c) comprises from 5 to 50 percent by weight based on the total weight of component (b);

(ii) component (d) comprises from 0.01 to 10 percent by weight based on the total weight of component (b); and

(iii) the amount of component (a) is such that said reaction mixture has an isocyanate index of from 70 to 130.

7. The process of claim 6, wherein

(i) component (c) comprises from 5 to 35 percent by weight based on the total weight of component (b);

(ii) component (d) comprises from 0.05 to 1 percent by weight based on the total weight of component (b); and

(iii) the amount of component (a) is such that said reaction mixture has an isocyanate index of

8. The process of claim 1, wherein said hydroxyl group containing compound is selected from the group consisting of polyethers, polyesters, polythioethers, polyacetals, polycarbonates, polyester amides and mixtures thereof.

9. The process of claim 1, wherein said hydroxyl group containing compound is a polyhydroxyl polyether having at least two hydroxyl groups.

10. The process of claim 9, wherein said polyether has a molecular weight of from 3,000 to 7,000 and contains 3 hydroxyl groups.

11. The process of claim 1, wherein said catalyst is selected such that said reaction mixture has a flow time of less than 15 seconds.

12. The process of claim 11, wherein said catalyst is selected such that said reaction mixture has a flow time of less than 10 seconds.

13. The process of claim 12, wherein said catalyst is selected such that said reaction mixture has a flow time of less than 5 seconds.

14. The process of claim 1, wherein said polyisocyanates based on 4,4'"'"'-diisocyanatodiphenylmethane are liquid at room temperature.

15. An active hydrogen containing blend for use in the production of polyurethane moldings comprising:

(a) an organic hydroxyl group containing compound having a molecular weight of from 1,800 to 12,000, and

(b) a chain extender which is miscible with polyhydroxyl compounds in any proportion and is selected from the group consisting of active aromatic diamines, having alkyl groups of from 1 to 3 carbon atoms in the ortho-position to each amino group, with the proviso that at least two of said alkyl substituents contain 2 or 3 carbon atoms.

16. The composition of claim 15, wherein said blend also contains a catalyst for reaction between hydroxyl groups and isocyanate groups.

17. The composition of claim 15, wherein said chain extender contains at least one linear alkyl substituent in the ortho-position to a first amino group and two linear alkyl substituents in the ortho-position to a second amino group.

18. The composition of claim 15, wherein said chain extender is selected from the group consisting of 1-methyl-3,5-diethyl-2,4-diamino benzene;

1-methyl-3,5-diethyl-2,6-diamino benzene;

1,3,5-triethyl-2,6-diamino benzene;

3,5,3'"'"',5'"'"'-tetraethyl-4,4'"'"'-diaminodiphenyl methane; and

mixtures thereof.

19. The composition of claim 18, wherein said chain extender is selected from the group consisting of 1-methyl-3,5-diethyl-2,4-diaminobenzene, 1-methyl-3,5-diethyl-2,6-diaminobenzene, and mixtures thereof.

20. The composition of claim 15, wherein said chain extender comprises from 5 to 50 percent by weight based on the total weight of said hydroxyl group containing compound.

21. The composition of claim 20, wherein said chain extender comprises from 5 to 35 percent by weight based on the total weight of said hydroxyl group containing compound.

22. The composition of claim 15, wherein said polyhydroxyl compound is selected from the group consisting of polyethers, polyesters, polythioethers, polyacetals, polycarbonates, polyester amides and mixtures thereof.

23. The composition of claim 15, wherein said hydroxyl group containing compound is a polyhydroxyl polyether having at least two hydroxyl groups.

24. The composition of claim 23, wherein said polyether has a molecular weight of from 3,000 to 7,000 and contains 3 hydroxyl groups.

25. In a process for the production of polyurethane elastomer moldings having a compact surface from a reaction mixture by a reaction injection molding process, wherein said reaction mixture comprises the following components:

(a) 4,4'"'"'-diisocyanatodiphenylmethane, polyisocyanates based on 4,4'"'"'-diisocyanatodiphenylmethane or mixtures thereof;

(b) hydroxyl group containing compounds;

(c) a chain extender; and

(d) a catalyst for the reaction between hydroxyl groups and isocyanate groups;

the improvement wherein said chain extender is miscible with polyhydroxyl compounds in any proportion and is selected from the group consisting of active aromatic diamines, which contain at least one alkyl substituent in the ortho-position to a first amino group and two alkyl substituents in the ortho-position to a second amino group, or mixtures thereof, with the proviso that at least two of said alkyl substituents contain at least two carbon atoms, and where said components (a), (b), (c) and (d) are processed via the one-shot process whereby (a) is mixed simultaneously either with (b), (c) and (d) or with a non-reacted premixture of some or all of (b), (c), and (d).

26. The process of claim 25, wherein said reaction mixture contains no blowing agent.

27. The process of claim 26, wherein said chain extender is selected from the group consisting of 1-methyl-3,5-diethyl-2,4-diamino benzene;

1-methyl-3,5-diethyl-2,6-diamino-benzene; and

mixtures thereof.

28. The process of claim 25, wherein said reaction mixture also contains a blowing agent and wherein said moldings are further characterized as having a cellular core.

29. The process of claim 25, wherein said chain extender has linear alkyl substituents of 2 or 3 carbon atoms in both ortho-positions to each amino group.

30. The process of claim 29, wherein said chain extender is either in liquid form or is dissolved in said hydroxyl group containing compound.

31. The process of claim 25, wherein said polyisocyanates based on 4,4'"'"'-diisocyanatodiphenylmethane are liquid at room temperature.

32. The process of claim 25, wherein

(i) component (c) comprises from 5 to 50 percent by weight based on the total weight of component (b);

(ii) component (d) comprises from 0.01 to 10 percent by weight based on the total weight of component (b); and

(iii) the amount of component (a) is such that said reaction mixture has an isocyanate index of from 70 to 130.

33. The process of claim 32, wherein

(i) component (c) comprises from 5 to 35 percent by weight based on the total weight of component (b);

(ii) component (d) comprises from 0.05 to 1 percent by weight based on the total weight of component (b); and

(iii) the amount of component (a) is such that said reaction mixture has an isocyanate index of from 90 to 110.

34. The process of claim 25, wherein said hydroxyl group containing compound is selected from the group consisting of polyethers, polyesters, polythioethers, polyacetals, polycarbonates, polyester amides and mixtures thereof.

35. The process of claim 25, wherein said hydroxyl group containing compound has a molecular weight of from 1,800 to 12,000 and has at least two hydroxyl groups.

36. The process of claim 35, wherein said hydroxyl group containing compound is a polyhydroxyl polyether and has a molecular weight of from 3000 to 7000 and contains 3 hydroxyl groups.

37. The process of claim 25, wherein said catalyst is selected such that said reaction mixture has a flow time of less than 15 seconds.

38. The process of claim 37, wherein said catalyst is selected such that said reaction mixture has a flow time of less than 10 seconds.

39. The process of claim 38, wherein said catalyst is selected such that said reaction mixture has a flow time of less than 5 seconds.

40. An active hydrogen containing blend for use in the production of polyurethane moldings comprising:

(A) an organic hydroxyl group containing compound, and

(B) from 5 to 50 percent by weight based on the weight of (A) of a chain extender which is miscible with polyhydroxyl compounds in any proportion and is selected from the group consisting of aromatic diamines which contain at least one alkyl substituent in the ortho-position to a first amino group and two alkyl substituents in the ortho-position to a second amino group or mixtures thereof, with the proviso that at least two of said alkyl substituents contain at least two carbon atoms.

41. The composition of claim 40, wherein said blend also contains a catalyst for reaction between hydroxyl groups and isocyanate groups.

42. The composition of claim 40, wherein said chain extender comprises from 5 to 35 percent by weight based on the total weight of said hydroxyl group containing compound.

43. The composition of claim 40, wherein said polyhydroxyl compound is selected from the group consisting of polyethers, polyesters, polythioethers, polyacetals, polycarbonates, polyester amides and mixtures thereof.

44. The composition of claim 40, wherein said polyhydroxyl group containing compound has a molecular weight of from 1,800 to 12,000.

45. The composition of claim 44, wherein said hydroxyl group containing compound is a polyhydroxyl polyether having at least two hydroxyl groups.

46. The composition of claim 45, wherein said polyether has a molecular weight of from 3,000 to 7,000 and contains 3 hydroxyl groups.