Composition for promoting adhesion of curable silicones to substrates

• US 4,525,400 A
• Filed: 05/25/1984
• Issued: 06/25/1985
• Est. Priority Date: 09/27/1982
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Surprenant, Richard P.
• Primary Examiner(s): Marquis, Melvyn I.
• Application Number:
  US06/609,141
• Time in Patent Office: 396 Days
• Field of Search: 428/54, 428/58, 428/447, 156/329, 556/434
• US Class Current: 428/54
• CPC Class Codes: C08G 77/12 containing silicon bound to hydrogen C08G77/045 takes precedence
• CPC Class Codes: C08G 77/16 to hydroxyl groups
• CPC Class Codes: C08G 77/18 to alkoxy or aryloxy groups
• CPC Class Codes: C08G 77/24 halogen-containing groups
• CPC Class Codes: C08G 77/46 containing polyether sequences
• CPC Class Codes: C08G 77/70 Siloxanes defined by use of the MDTQ nomenclature
• CPC Class Codes: C08L 2666/44 Silicon-containing compounds
• CPC Class Codes: C08L 83/04 Polysiloxanes
• CPC Class Codes: Y10S 528/902 Particulate material prepared from an isocyanate
• CPC Class Codes: Y10T 428/18 Longitudinally sectional layer of three or more sections
• CPC Class Codes: Y10T 428/192 Sheets or webs coplanar
• CPC Class Codes: Y10T 428/31663 As siloxane, silicone or silane

Abstract

The adhesion of self-bonding, low modulus, one package, room temperature vulcanizable silicone compositions to a variety of substrates is effectively promoted by incorporating in the silicone composition, before curing, a small effective amount of an adhesion promoting composition comprising predominantly at least one diorganocyclopolysiloxane compound of the formula: ##STR1## wherein R¹ may be C₁ -C₆ alkyl, C₁ -C₆ gamma-trihaloalkyl or phenyl; R² is alkylene of from 2 to 6 carbon atoms; R³, R⁴ and R⁵ are, independently, C₁ -C₆ alkyl or C₂ -C₆ alkanoyl; and n is either 3 or 4.

Claims

1. A diorganocyclopolysiloxane compound of the formula:

##STR41## wherein R¹ is C₁ -C₆ alkyl, C₁ -C₆ gamma-trihaloalkyl or phenyl;

R² is alkylene of from 2 to 6 carbon atoms;

R³, and R⁴, and R⁵ are, independently, C₁ -C₆ alkyl, or C₂ -C₆ alkanoyl and n is 3 or 4.

2. A diorganocyclotrisiloxane compound of the formula:

##STR42## wherein R¹ is C₁ -C₆ alkyl, C₁ -C₆ gamma-trihaloalkyl or phenyl;

R² is alkylene of from 2 to 6 carbon atoms; and

R³, R⁴ and R⁵ are, independently, C₁ -C₆ alkyl or C₂ -C₆ alkanoyl.

3. A diorganocyclotetrasiloxane compound of the formula:

##STR43## wherein R¹ is C₁ -C₆ alkyl, C₁ -C₆ gamma-trihaloalkyl or phenyl;

R² is alkylene of from 2 to 6 carbon atoms; and

R³, R⁴ and R⁵ are, independently, C₁ -C₆ alkyl or C₂ -C₆ alkanoyl.

4. A process for the preparation of diorganocyclopolysiloxane of the formula:

##STR44## wherein R¹ is C₁ -C₆ alkyl, C₁ -C₆ gamma-trihaloalkyl or phenyl;

R² is alkylene of from 2 to 6 carbon atoms;

R³, R⁴ and R⁵ are, independently, C₁ -C₆ alkyl or C₂ -C₆ alkanoyl and n is either 3 or 4, said process comprising;

(a) dissolving an alkylhydrogencyclopolysiloxane of the formula;

##STR45## wherein R¹ and n are as defined above, in an aromatic organic solvent to form an approximately 20% by weight solution;

(b) heating said solution to reflux;

(c) adding a minor effective amount of a platinum silicone complex catalyst;

(d) thereafter adding a vinyl or a vinyl C₂ -C₄ alkyl-trialkoxy or triacyloxysilane of the formula;

##STR46## wherein R² is a vinyl or CH₂ ═

CH--(CH₂)_m group where m has a value of 1 to 4 inclusive and R³, R⁴ and R⁵ are as defined above in an amount sufficient to provide a slight excess of the amount needed to effect a vinyl addition reaction at each Si--H bond of said alkylhydrogencyclopolysiloxane;

(e) allowing the reaction therebetween to continue until substantially complete; and

(f) finally, removing said aromatic organic solvent to leave the diorganocyclopolysiloxane product.

5. A process as recited in claim 4 wherein said alkylhydrogencyclopolysiloxane of step (a) is a 1,3,5-tris-alkylhydrogencyclotrisiloxane.

6. A process as recited in claim 4 wherein the alkylhydrogencyclopolysiloxane is 1,3,5-tris-methylhydrogencyclotrisiloxane.

7. A process as recited in claim 4 wherein the alkylhydrogencyclopolysiloxane is an alkylhydrogencyclotetrasiloxane.

8. A process as recited in claim 4 wherein the alkylhydrogencyclopolysiloxane is 1,3,5,7-tetramethyl-1,3,5,7-tetrakis-methylhydrogencyclotetrasiloxane.

11. The process as recited in claim 4 wherein said diorganocyclopolysiloxane product is 1,3,5-trimethyl-1,3,5-tris-2-trimethoxysilylethylcyclotrisiloxane.

12. A process a recited in claim 4 wherein the diorganocyclopolysiloxane product is 1,3,5,7-tetramethyl-1,3,5,7-tetrakis-2-trimethoxysilyethylcyclotetrasiloxane.

9. An article of manufacture comprising a plurality of pieces, each piece having at least a part of a surface portion in close proximity to another piece, and having an adhesive joint therebetween, said adhesive joint comprising a low modulus, rubbery, moisture cured composition comprising:

(a) a silanol or polyalkoxy chain-stopped diorganopolysiloxane;

(b) a silane or polysilane crosslinker therefor;

(c) a catalyst capable of promoting the reactions between (a) and (b); and

(d) a small, effective, adhesion promoting amount of a composition comprising at least one compound of the formula;

##STR47## wherein R¹ is C₁ -C₆ alkyl, C₁ -C₆ gamma-trihaloalkyl or phenyl;

R² is alkylene of from 2 to 6 carbon atoms;

R³, R⁴ and R⁵ are, independently, C₁ -C₆ alkyl or C₂ -C₆ alkanoyl and n is 3 or 4.

10. A method of bonding a plurality of articles comprising:

(a) providing a plurality of articles;

(b) applying a layer of moisture-curable, adhesive joint forming composition to at least a portion of a surface of at least one of the articles;

(c) bringing at least two surfaces of at least two of said articles into proximity so as to complete formation of a moisture curable adhesive joint therebetween; and

(d) exposing the article of step (c) to moisture until the adhesive joint forming composition has cured to a firmly adhered rubbery material, said moisture curable adhesive joint forming composition comprising;

(i) a silanol or polyalkoxy chain-stopped polydiorganosiloxane;

(ii) a silane or polysilane crosslinker therefor;

(iii) a catalyst capable of promoting the reactions between (i) and (ii); and

(iv) a small, effective, adhesion promoting amount of a composition comprising at least one diorganocyclopolysiloxane compound of the formula;

##STR48## wherein R¹ is C₁ -C₆ alkyl, C₁ -C₆ gamma trihaloalkyl or phenyl;

R² is alkylene of from 2 to 6 carbon atoms;

R³, R⁴ and R⁵ are, independently C₁ -C₆ alkyl or C₂ -C₆ alkanoyl and n is 3 or 4.