Liquid aryl group-containing polyorganosiloxane

1. A liquid aryl group-containing polyorganosiloxane comprising an arylsiloxy unit represented by RSiO 3/2 , wherein R is an aryl group, and wherein the arylsiloxy unit constitutes from 20 to 50 mol % of all the siloxy units constituting the polyorganosiloxane, and an average number of moles of aryl groups per one mole of Si atoms in the polyorganosiloxane is within a range of 1.20 to 1.65, wherein the liquid aryl group-containing polyorganosiloxane is represented by the following average composition formula (1-1):

Average composition formula (1-1):

(R A 2 R 6 SiO 1/2 ) a′ (R A R 7 SiO 2/2 ) b′ (R A SiO 3/2 ) c′   (1-1)

wherein, R A is a phenyl group or a naphthyl group, R 6 and R 7 are each independently a monovalent organic group or a hydrogen atom, 0.10≦b′≦0.40 and 0.20≦c′≦0.50, a′+b′+c′=1.0, and a number of moles of phenyl groups or naphthyl groups per one mole of Si atoms in the polyorganosiloxane of a′ to c′ is, on average, in a range of 1.20 to 1.65.

2. The liquid aryl group-containing polyorganosiloxane according to claim 1 , in which a refractive index is not less than 1.50, and a weight average molecular weight as measured by gel permeation chromatography (GPC) is in a range of 500 to 2,000.

3. An aryl group-containing polyorganosiloxane composition comprising: (A) a liquid aryl group-containing polyorganosiloxane according to claim 1 , and (B) an oil agent different from component (A), wherein an overall refractive index of the composition is not less than 1.45, and an overall viscosity at 25° C. of the composition is in a range of 100 to 100,000 mPa·s.

4. The aryl group-containing polyorganosiloxane composition according to claim 3 , wherein the component (B) is a phenyl group-containing organopolysiloxane represented by structural formula (2-1) or structural formula (2-2) below:

wherein each R 8 is independently a group selected from a phenyl group, an aralkyl group, a hydrogen atom, a hydroxyl group, or a fluorinated alkyl group or an alkyl group having from 1 to 20 carbons and, in terms of molar ratio, at least 50% of the R 8 moieties are phenyl groups; n1 or n2 is a number in a range of 0 to 1,000; and n3 is a number in a range of 1 to 1,000.

5. A cosmetic composition comprising a liquid aryl group-containing polyorganosiloxane composition according to claim 3 .

6. The cosmetic composition according to claim 5 , further comprising: (C) one or more types of oleophilic cosmetic raw material.

7. The aryl group-containing polvorganosiloxane composition according to claim 3 , wherein the liquid aryl group-containing polyorganosiloxane has a refractive index not less than 1.50, and a weight average molecular weight as measured by gel permeation chromatography (GPC) is in a range of 500 to 2,000.

8. A cosmetic composition comprising a liquid aryl group-containing polyorganosiloxane according to claim 1 .

9. The cosmetic composition according to claim 8 that is a makeup cosmetic composition, a hair cosmetic composition, or a skin cosmetic composition.

10. A method for producing a liquid aryl group-containing polyorganosiloxane comprising: a step (I) of mixing (A-1) at least one organosilicon compound selected from an aryl group-containing polyorganosiloxane that is solid at 25° C. and that comprises an arylsiloxy unit represented by RSiO 3/2 , wherein R is an aryl group, wherein the arylsiloxy unit constitutes not less than 50 mol % of all the siloxy units constituting the polyorganosiloxane; an organosilane represented by RSiX 3-n4 (OR 9 ) n4 , wherein R is an aryl group, X is a halogen atom, R 9 are each independently a hydrogen atom or an alkyl group having from 1 to 6 carbons, and n 4 is a number within a range of 0 to 3; and a condensation reaction product of said organosilane;

(A-2) an aryl group-containing organopolysiloxane oligomer represented by structural formula (3) below:

wherein R 10 are each independently a monovalent organic group and, at least 50% of the R 10 moieties are aryl groups, and n5 is a number in a range of 0 to 10; and (A-3) a catalyst; and

a step (II) of reacting the mixture obtained in step (I) to obtain an equilibration reaction;

wherein the liquid aryl group-containing polyorganosiloxane includes an arylsiloxy unit represented by RSiO 3/2 , wherein R is an aryl group, and wherein the arylsiloxy unit constitutes from 20 to 50 mol % of all the siloxy units constituting the polyorganosiloxane, and an average number of moles of aryl groups per one mole of Si atoms in the polyorganosiloxane is within a range of 1.20 to 1.65.

11. The method for producing the liquid aryl group-containing polyorganosiloxane according to claim 10 , in which the liquid aryl group-containing polvorganosiloxane has a refractive index is not less than 1.50, and a weight average molecular weight as measured by gel permeation chromatography (GPC) is in a range of 500 to 2,000.

12. A cosmetic composition comprising a liquid aryl group-containing polyorganosiloxane comprising an arylsiloxy unit represented by RSiO 3/2 , wherein R is an aryl group, and wherein the arylsiloxy unit constitutes from 20 to 50 mol % of all the siloxy units constituting the polyorganosiloxane, and an average number of moles of aryl groups per one mole of Si atoms in the polyorganosiloxane is within a range of 1.20 to 1.65, wherein the liquid aryl group-containing polyorganosiloxane is present in the cosmetic composition in an amount of from 0.5-50 wt. % based on the total weight of the cosmetic composition.

13. The cosmetic composition according to claim 12 , further comprising: (C) one or more types of oleophilic cosmetic raw material.

14. The cosmetic composition according to claim 12 that is a makeup cosmetic composition, a hair cosmetic composition, or a skin cosmetic composition.