Organopolysiloxane compositions for antiadhesive/release coatings

• US 4,640,939 A
• Filed: 10/15/1985
• Issued: 02/03/1987
• Est. Priority Date: 10/15/1984
• Status: Expired due to Fees

• Current Assignee: Rhone-Poulenc Specialites Chimiques (Sanofi )
• Original Assignee: Rhone-Poulenc Specialites Chimiques (Sanofi )
• Inventors: Soula, Gerard, Cavezzan, Jacques
• Primary Examiner(s): Marquis, Melvyn I.
• Application Number:
  US06/787,065
• Time in Patent Office: 476 Days
• Field of Search: 528/15, 528/31, 528/32, 427/387, 428/447, 522/99
• US Class Current: 522/99
• CPC Class Codes: C08G 77/12 containing silicon bound to hydrogen C08G77/045 takes precedence
• CPC Class Codes: C08G 77/20 containing silicon bound to unsaturated aliphatic groups C08G77/045 takes precedence
• CPC Class Codes: C08G 77/24 halogen-containing groups
• CPC Class Codes: C08G 77/44 containing only polysiloxane sequences
• CPC Class Codes: C08G 77/70 Siloxanes defined by use of the MDTQ nomenclature
• CPC Class Codes: C08K 5/23 Azo-compounds
• CPC Class Codes: C08K 5/235 Diazo and polyazo compounds
• CPC Class Codes: C08K 5/56 Organo-metallic compounds, i.e. organic compounds containing a metal-to-carbon bond
• CPC Class Codes: C08L 2666/28 Non-macromolecular organic substances
• CPC Class Codes: C08L 83/00 Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 83/04 Polysiloxanes
• CPC Class Codes: Y10S 522/904 Monomer or polymer contains initiating group
• CPC Class Codes: Y10T 428/31663 As siloxane, silicone or silane

Abstract

Gelation-resistant, high pot life organopolysiloxane compositions adapted for antiadhesive/release coating applications, are comprised of (1) at least one substantially straight-chain organopolysiloxane having a viscosity ranging from about 50 to 100,000 mPa.s at 25° C. and containing at least x alkenyl unsaturated hydrocarbon groups bonded to a silicon atom, per molecule, wherein x≧2, (2) at least one organohydropolysiloxane crosslinking agent having a viscosity ranging from about 10 to 100,000 mPa.s at 25° C. and containing at least y hydrogen atoms bonded to silicon atoms, per molecule, wherein y≧2, (3) a catalytically effective amount of a platinum group metal crosslinking catalyst, and (4) an effective amount of at least one azodicarboxylate gelation inhibitor which is inert to the activity of said catalyst (3), but in insufficient amount as to prevent the crosslinking of said polysiloxanes (1) and (2) under crosslinking conditions.

Claims

1. A curable organopolysiloxane composition of matter, comprising (1) at least one substantially straight-chain organopolysiloxane having a viscosity ranging from about 50 to 100,000 mPa.s at 25°

C. and containing at least x alkenyl unsaturated hydrocarbon groups bonded to a silicon atom, per molecule, wherein x≧

2, (2) at least one organohydropolysiloxane crosslinking agent having a viscosity ranging from about 10 to 100,000 mPa.s at 25°

C. and containing at least y hydrogen atoms bonded to silicon atoms, per molecule, wherein y≧

2, (3) a catalytically effective amount of a platinum group metal crosslinking catalyst, and (4) an effective amount of at least one azodicarboxylate gelation inhibitor which is inert to the activity of said catalyst (3) and which inhibits gel formation at ambient temperatures, but in insufficient amount as to prevent the crosslinking of said polysiloxanes (1) and (2) under cross-linking conditions.

2. The organopolysiloxane composition as defined by claim 1, wherein x+y≧

5.

3. The organopolysiloxane composition as defined by claim 2, wherein said azodicarboxylate (4) has the general formula:

space="preserve" listing-type="equation">R.sub.1 OCC--N═

N--COOR.sub.2 (I)

or

space="preserve" listing-type="equation">R'"'"'.sub.1 OOC--N═

N--COO--R--OOC--N═

N--COOR'"'"'.sub.2 (II)

in which R₁, R₂, R'"'"'₁ and R'"'"'₂, which may be identical or different, are each a straight or branched chain alkyl radical having from 1 to 12 carbon atoms, and R is an alkylene radical, --CH₂)_n, wherein n ranges from 1 to 12.

4. The organopolysiloxane composition as defined by claim 3, wherein said azodicarboxylate (4) has the general formula (I).

5. The organopolysiloxane composition as defined by claim 3, wherein said azodicarboxylate (4) has the general formula (II).

6. The organopolysiloxane composition as defined by claim 4, wherein said azodicarboxylate (4) comprises methyl or ethyl azodicarboxylate.

7. The organopolysiloxane composition as defined by claim 3, said organopolysiloxane (1) containing essentially only methyl and vinyl groups per molecule, and said organohydropolysiloxane (2) containing essentially only methyl and .tbd.SiH groups per molecule.

8. The organopolysiloxane composition as defined by claim 3, said azodicarboxylate (4) having a boiling point of at least 25°

C.

9. The organopolysiloxane composition as defined by claim 3, comprising, per 100 parts by weight of said organopolysiloxane (1), about 0.1 to 50 parts by weight of said organohydropolysiloxane (2), and about 0.01 to 3 parts by weight of said azodicarboxylate (4).

10. The organopolysiloxane composition as defined by claim 9, comprising from about 5 to 1,000 ppm of said catalyst (3).

11. The organopolysiloxane composition as defined by claim 2, dispersed in or diluted with a volatile organic solvent compatible therewith.

12. The organopolysiloxane composition as defined by claim 11, said solvent comprising from about 50 to 99% by weight thereof.

13. The organopolysiloxane composition as defined by claim 2, having a viscosity not exceeding 5,000 mPa.s at 25°

C.

14. A shaped substrate coated with a layer of the organopolysiloxane composition as defined by claim 1.

15. The shaped substrate as defined by claim 14, the same comprising a metal, wood, glass, paper, or plastic substrate.

16. The shaped substrate as defined by claim 15, coated with a thin peelable layer of said organopolysiloxane composition.

17. A process for forming an organopolysiloxane coating composition comprising crosslinking the composition of claim 1 with ultraviolet radiation.