Silicone elastomers compositions

Details Silicone elastomers compositions Silicone elastomers compositions

2002-08-27

2004-08-03

Peng, Kuo-Liang (Department: 1712)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

At least one aryl ring which is part of a fused or bridged...

C528S031000, C528S032000, C528S025000, C556S445000, C424S065000, C424S070100, C424S078020

Reexamination Certificate

active

06770708

ABSTRACT:

FIELD OF THE INVENTION
This invention is directed to an elastomer composition produced by cross-linking a high molecular weight ≡Si—H containing polysiloxane and a diene, diyne or ene-yne compound in the presence of a diluent. The elastomer composition is suitable for use in forming personal care compositions.
BACKGROUND OF THE INVENTION
Cross-links are junctions of polymer strands in a three-dimensional network. They may be viewed as long-chain branches that are so numerous that a continuous insoluble network or gel is formed.
Increasingly, platinum catalyzed hydrosilylation reactions are being used to form networks. They typically involve reactions between a low molecular weight polysiloxane containing several ≡Si—H groups, and a high molecular weight polysiloxane containing several ≡Si-vinyl groups, or vice versa.
Attractive features of this mechanism are that (i) no by-products are formed, (ii) cross-linking sites and hence network architecture can be narrowly defined, and (iii) hydrosilylation will proceed even at room temperature to form the networks. In the mechanism, crosslinking involves addition of ≡SiH across multiple bonds, i.e., ≡SiH+CH
2
═CH—R→≡SiCH
2
CH
2
—R.
U.S. Pat. No. 5,654,362 also disclosed a method of making silicone elastomers comprising (A) an ≡Si—H containing polysiloxane of formula R
3
SiO(R′
2
SiO)
a
(R″HSiO)
b
SiR
3
and optionally an ≡Si—H containing polysiloxane of formula HR
2
SiO(R′
2
SiO)
c
SiR
2
H or formula HR
2
SiO(R′
2
SiO)
a
(R″HSiO)
b
SiR
2
H where R, R′, and R″ are alkyl groups of 1-6 carbon atoms; a is 0-250; b is 1-250; and c is 0-250; with (B) an alpha, omega-diene as only the unsaturated hydrocarbon of formula CH
2
═CH(CH
2
)
x
CH═CH
2
where x is 1-20; conducting the reaction in the presence of a platinum catalyst and (C) a solvent selected from the group consisting of (i) organic compounds, (ii) compounds containing a silicon atom, (iii) mixtures of organic compounds, (iv) mixtures of compounds containing a silicon atom, and (v) mixtures of organic compounds and compounds containing a silicon atom; and continuing the reaction until a gel is formed by crosslinking and addition of ≡Si—H across double bonds in the alpha, omega-diene.
A need still exists, however, for new silicone elastomers to have improved properties. It has been found that by using a higher molecular weight ≡SiH containing polysiloxane, the elastomer composition comprised of silicone elastomers have unique sensory benefits, thickening efficiency, and/or reduced syneresis properties.
SUMMARY OF THE INVENTION
This invention relates to an elastomer composition comprising
(A) a silicone elastomer having a first polymeric unit of the average formula:
where each R
1
is independently a monovalent hydrocarbon group having 1 to 30 carbon atoms;
R
2
is a hydrogen (H) atom
R
3
is a cross-link —E—Y—E—, wherein one end of the cross-link is bonded to a second polymeric unit; each E is a divalent group selected from —CH
2
CH
2
— or —CH═CH— and Y is a divalent group that is a hydrocarbon, a siloxane or any combination of these; and
a is 265 to 2000, b is 0 to 249 and c is 1 to 250 with the provision that b+c≦250 and
(B) a diluent.
Another embodiment of this invention to provide a method for making an elastomer composition wherein the method comprises
(1) reacting in the presence of a hydrosilylation catalyst
(a) a ≡Si—H containing polysiloxane having an average formula
R
1
3
SiO(R
1
2
SiO)
a
(R
1
HSiO)
d
SiR
1
3
where each R
1
is independently a monovalent hydrocarbon group having 1 to 30 carbon atoms; a is 265 to 2000; and d is 1 to 250; with
(b) a diene, diyne or ene-yne compound; wherein (a) and (b) are dispersed in
(c) a diluent; and
(2) continuing the reaction until a silicone elastomer is formed by crosslinking and addition of ≡Si—H across unsaturated bonds in the diene, diyne or ene-yne compound.
In another embodiment of this invention, the elastomer composition is crumbled into a silicone powder using mechanical force.
In another embodiment of this invention, a base composition is formed by subjecting to a shear force a composition comprising (I) the elastomer composition and (II) a second diluent.
DETAILED DESCRIPTION OF THE INVENTION
This invention pertains to an elastomer composition comprising
(A) a silicone elastomer having a first polymeric unit of the average formula:
where each R
1
is independently a monovalent hydrocarbon group having 1 to 30 carbon atoms;
R
2
is a hydrogen (H) atom
R
3
is a cross-link —E—Y—E—, wherein one end of the cross-link bonded to a second polymeric unit; each E is a divalent group selected from —CH
2
CH
2
— or —CH═CH— and Y is a divalent group that is a hydrocarbon, a siloxane or any combination of these; and
a is 265 to 2000 (alternatively 350 to 1000), b is 0 to 249 (alternatively 0 to 100) and c is 1 to 250 (alternatively 1 to 100) with the provision that b+c≦250 (alternatively ≦100) and
(B) a diluent.
In the first polymeric unit R
1
is a monovalent hydrocarbon group having 1 to 30 carbon atoms. R
1
may be exemplified by, but not limited to, alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl or isobutyl; aryl groups such as phenyl, biphenyl, naphthyl or anthracyl; alkaryl groups such as tolyl or xylyl; aralkyl groups such as benzyl, phenylethyl or 2-phenylpropyl, or polyether.
In the first polymeric unit, R
3
is a crosslink of the formula —E—Y—E— where each E is a divalent group independently selected from —CH
2
CH
2
— or —CH═CH—. Typically each E is —CH
2
CH
2
— and Y is a hydrocarbon group having 1 to 30 carbon atoms alternatively 1 to 10 carbon atoms. In the cross-link Y is a divalent group that is a hydrocarbon, a siloxane or any combination of these. When Y is a siloxane it typically has the formula
where R
1
is as previously defined and p is 0 to 20,000, alternatively 0 to 500.
R
3
may be exemplified by, but not limited to, polyether, pentylene, hexylene, heptylene, octylene, nonylene, decylene, dodecylene, tetradecylene and mixtures thereof.
One end of R
3
is bonded into the first polymeric unit shown in formula (I). The other end of R
3
is bonded to a second polymeric unit having the formula (≡Si—O
1/2
) wherein the remaining two bond sites on the Si in this unit may be oxygen, R
1
or any combination thereof. The second polymeric unit may be the same as or different from polymeric unit (I). Typically the other end of R
3
is bonded into a second polymeric unit having the formula (II):
wherein each R
15
, R
16
, and R
17
is independently selected from hydrogen or a monovalent hydrocarbon group having 1 to 30 carbon atoms; and i is 0 to 2000, j is 0 to 250 and k is 1 to 250.
R
15
, R
16
and R
17
may be exemplified by, but not limited to hydrogen, alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl or isobutyl; aryl groups such as phenyl, biphenyl, naphthyl or anthracyl; alkaryl groups such as tolyl or xylyl, or aralkyl groups such as benzyl, phenylethyl or 2-phenylpropyl, or polyether.
The amount of cross-link in the silicone elastomer is from 0.01 to 90 mole %, alternatively 1 to 20 mole %.
The silicone elastomer typically contains from 10 to 40,000 of the total polymeric units (e.g. first and second polymeric units).
The elastomer composition of the instant invention also comprises a diluent (B). Suitable examples of diluents include silicones, both linear and cyclic (other than those used to prepare corresponding silicone elastomer (A)), organic oils, organic solvents and mixtures of these. Specific examples of diluents may be found in U.S. Pat. No. 6,200,581, which is hereby incorporated by reference for this purpose. Non-reactive or relatively non-reactive diluents are preferred. For purposes here, non-reactive is used in reference to the associated cross-linking reaction and used relative to the (other) reactants therein. A relatively non-reactive diluent would be less than one tenth as reactive with

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