Adhesion of aramid cords to rubber

• US 4,469,748 A
• Filed: 07/05/1983
• Issued: 09/04/1984
• Est. Priority Date: 07/05/1983
• Status: Expired due to Fees

• Current Assignee: The General Tire & Rubber Company
• Original Assignee: The General Tire & Rubber Company
• Inventors: Sharma, Satish C.
• Primary Examiner(s): Pertilla, Theodore E.
• Application Number:
  US06/510,715
• Time in Patent Office: 427 Days
• Field of Search: 525/133, 525/139, 524/510, 524/511, 156/110 A, 156/331.6, 156/335, 204/164, 427/38, 427/322, 428/378, 428/395, 428/267
• US Class Current: 428/378
• CPC Class Codes: C08J 2321/00 Characterised by the use of unspecified rubbers
• CPC Class Codes: C08J 5/06 using pretreated fibrous materials
• CPC Class Codes: D06M 10/025 Corona discharge or low temperature plasma
• CPC Class Codes: D06M 2101/36 Aromatic polyamides
• CPC Class Codes: D06M 2200/50 Modified hand or grip properties; Softening compositions
• CPC Class Codes: Y10S 156/91 Bonding tire cord and elastomer: improved adhesive system
• CPC Class Codes: Y10T 428/2938 Coating on discrete and individual rods, strands or filaments
• CPC Class Codes: Y10T 428/2969 Polyamide, polyimide or polyester
• CPC Class Codes: Y10T 442/3911 Natural or synthetic rubber sheet or film

Abstract

An aramid reinforcing element is treated with a cold gas plasma of air, N₂, He, Ne or Ar or mixture thereof at up to 300 watts power for a few seconds to several minutes to improve its adhesion to rubber compounds.

Claims

1. A method for adhering a poly(p-phenylene terephthalamide) reinforcing element to a rubber compound which comprises (I) treating said element with a composition comprising an aqueous alkaline dispersion of about 10 to 50% by weight of solids comprising (a) a rubbery vinyl pyridine copolymer and (b) a water soluble thermosetting phenolic-aldehyde resin in an amount of from about 3 to 25 parts by weight dry per 100 parts total by weight dry of (a), heating said treated element at a temperature of from about 200°

to 600°

F. for from about 300 to 5 seconds to remove essentially all of the water from said composition and to provide said element with a heat cured or heat set dry adhesive in an amount of up to about 20% total by weight (dry) based on the weight of said reinforcing element, and (II) combining said dried and heat cured adhesive containing reinforcing element with an unvulcanized vulcanizable rubber compound and vulcanizing the same, said reinforcing element prior to treatment with said composition having been treated in a cold gas plasma for from about 2 seconds to 30 minutes at from about 10 to 300 watts of power where said gas is selected from the group consisting of air, nitrogen, helium, neon and argon and mixture thereof.

2. A method according to claim 1 where said plasma is conducted from about 2 L to 20 minutes at about 25 to 75 watts of power.

3. A method according to claim 2 where said gas is nitrogen.

4. A method according to claim 2 where said gas is argon.

5. A method according to claim 1 where in (b) the resin comprises a mixture of a resorcinol-formaldehyde resin and a phenol-formaldehyde resin.

6. A method according to claim 1 where in (b) the resin comprises a resorcinol-formaldehyde resin.

7. A method according to claim 1 wherein said rubbery vinyl pyridine copolymer of (a) is a terpolymer of from about 60 to 80% by weight of butadiene-1,3, from about 7 to 32% by weight of styrene, and from about 4 to 22% by weight of 2-vinyl pyridine, wherein said phenolic-aldehyde resin of (b) is used in an amount of from about 6 to 20 parts by weight dry per 100 parts total by weight dry of (a), wherein said phenolic-aldehyde resin of (b) comprises a mixture of a phenol-formaldehyde resin and a resorcinol-formaldehyde resin, wherein said reinforcing agent contains up to about 15% total by weight of said dry adhesive and wherein the solids content of said dispersion is from about 20 to 25% by weight.

15. The product produced by the method of claim 1.

16. The method produced by the method of claim 2.

17. The product produced by the method of claim 3.

18. The product produced by the method of claim 4.

19. The product produced by the method of claim 5.

20. The product produced by the method of claim 6.

21. The product produced by the method of claim 7.

8. A method which comprises (I) treating a poly(p-phenylene terephthalamide) reinforcing element with a composition comprising an aqueous alkaline dispersion of about 10 to 50% by weight of solids comprising (a) a rubbery vinyl pyridine copolymer and (b) a water soluble thermosetting phenolic-aldehyde resin in an amount of from about 3 to 25 parts by weight dry per 100 parts total by weight dry of (a), heating said treated element at a temperature of from about 200°

to 600°

F. for from about 300 to 5 seconds to remove essentially all of the water from said composition and to provide said element with a heat cured or heat set dry adhesive in an amount of up to about 20% total by weight (dry) based on the weight of said reinforcing element, said reinforcing element prior to treatment with said composition having been treated in a cold gas plasma for from about 2 seconds to 30 minutes at from about 10 to 300 watts of power where said gas is selected from the group consisting of air, nitrogen, helium, neon and argon and mixture thereof.

9. A method according to claim 8 where said plasma is conducted from about 2 to 20 minutes at about 25 to 75 watts of power.

10. A method according to claim 9 where said gas is nitrogen.

11. A method according to claim 9 where said gas is argon.

12. A method according to claim 8 where in (b) the resin comprises a mixture of a resorcinol-formaldehyde resin and a phenol-formaldehyde resin.

13. A method according to claim 8 where in (b) the resin comprises a resorcinol-formaldehyde resin.

14. A method according to claim 8 wherein said rubbery vinyl pyridine copolymer of (a) is a terpolymer of from about 60 to 80% by weight of butadiene-1,3, from about 7 to 32% by weight of styrene, and from about 4 to 22% by weight of 2-vinyl pyridine, wherein said phenolic-aldehyde resin of (b) is used in an amount of from about 6 to 20 parts by weight dry per 100 parts total by weight dry of (a), wherein said phenolic-aldehyde resin of (b) comprises a mixture of a phenol-formaldehyde resin and a resorcinol-formaldehyde resin, wherein said reinforcing agent contains up to about 15% total by weight of said dry adhesive and wherein the solid contents of said dispersion is from about 20 to 25% by weight.

22. The product produced by the method of claim 8.

23. The product produced by the method of claim 9.

24. The product produced by the method of claim 10.

25. The product produced by the method of claim 11.

26. The product produced by the method of claim 12.

27. The product produced by the method of claim 13.

28. The product produced by the method of claim 14.