Polishing agent

A polishing agent comprising a composition prepared by mixing PA0 (I) a polymerization product obtained by addition polymerization of a particular organohydrogenpolysiloxane and a particular organopolysiloxane having silicon-bonded aliphatic unsaturated bonds, in the presence of from 10 to 200 parts by weight of a low-viscosity silicone oil per 100 parts by weight of the total amount of said organohydrogenpolysiloxane and said organopolysiloxane; and PA0 (II) a low-viscosity oil with a viscosity of not more than 10 cSt at 25.degree. C. This polishing agent has good durable water-resistance as well as has good workability in coating operation, and therefore is suited to cars, furniture and so forth.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a polishing agent. 
2. Description of the Prior Art 
As polishing agents that are coated on surfaces of cars, furniture, etc. 
for giving brightness thereto, emulsion type ones and oily type ones are 
heretofore known. 
Of these, the emulsion polishing agents are pasty or creamy and have a 
suitable softness (normally, have a viscosity of 1,000 cP or more at 
25.degree. C.), and therefore they are very easy to apply and have good 
workability in application. The oily polishing agents are in the form of 
solid, slightly soft paste or liquid, and have good durable 
water-resistance. 
However, the emulsion polishing agents have poor durable water-resistance 
owing to a surfactant contained therein as an emulsifying agent. 
Therefore, in particular, they are not satisfactory as a polishing agent 
for cars. On the other hand, the oily polishing agents have following 
disadvantages. The solid ones or slightly soft and pasty ones have poor 
coverability or spreadability and therfore have poor workability in 
coating operation; the liquid ones are liable to drip from the surfaces on 
which they are applied. In addition, it has been impossible to prepare an 
oily polishing agent having a softness suited to coating operation, 
because there is not known a suitable thickening agent that can be used to 
increase the viscosity of the low-viscosity oil used as a solvent, to an 
appropriate level. 
SUMMARY OF THE INVENTION 
Accordingly, an object of the present invention is to provide a polishing 
agent having good durable water-resistance and also having a softness 
suited to coating operation. 
As disclosed herein, as a means for solving the problems involved in the 
prior art, this invention provides a polishing agent comprising a 
composition prepared by mixing 
(I) a polymerization product obtained by addition polymerization of an 
organohydrogenpolysiloxane of (A) given below and an organopolysiloxane of 
(B) given below, in the presence of from 10 to 200 parts by weight of a 
low-viscosity silicone oil of (C) given below per 100 parts by weight of 
the total amount of said organohydrogenpolysiloxane of (A) and said 
organopolysiloxane of (B); 
(A): an organohydrogenpolysiloxane containing in its molecule not less than 
1.5 silicon-bonded hydrogen atoms on average; 
(B) an organopolysiloxane containing in its molecule not less than 1.5 
silicon-bonded aliphatic unsaturated groups on average; 
(C) a low-viscosity silicone oil with a viscosity of not more than 100 cSt 
at 25.degree. C., and 
(II) a low-viscosity oil with a viscosity of not more than 10 cSt at 
25.degree. C. 
The polishing agent of this invention has good durable water-resistance as 
well a has good workability in coating operation because of its viscosity 
suitable for the operation. Therefore, the polishing agent is suited to 
cars, furniture and so forth.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION 
(I) Polymerization Product 
The polishing agent of this invention comprises a composition prepared by 
mixing Components (I) and (II) described above. The polymerization product 
of (I) can be prepared by subjecting the reactive organopolysiloxanes of 
(A) and (B) to addition polymerization in the presence of the 
low-viscosity silicone oil of (C). In the polymerization product thus 
obtained, the low-viscosity silicone oil of (C) has been incorporated in 
the three-dimensional crosslinked structure of the polymer formed. 
(A) Organohydrogenpolysiloxane 
The (A) organohydrogenpolysiloxane includes those comprising some or all of 
an HSiO.sub.1.5 unit, an RSiO.sub.1.5 unit, an RHSiO unit, an R.sub.2 SiO 
unit, an R.sub.2 HSiO.sub.0.5 unit and an R.sub.3 SiO.sub.0.5 unit, 
wherein R is a substituted or unsubstituted monovalent hydrocarbon group 
except for an aliphatic unsaturated group, as exemplified by an alkyl 
group such as methyl, ethyl, propyl or butyl; an aryl group such as phenyl 
or tolyl; a monovalent hydrocarbon group including a cycloalkyl group such 
as cyclohexyl, and a substituted hydrocarbon group in which one or more 
hydrogen atoms possessed by the monovalent hydrocarbon group have been 
substituted with a halogen atom such as chlorine, bromine or fluorine, a 
cyano group, etc., as exemplified by a gamma-trifluoropropyl group and a 
chloromethyl group. This organohydrogenpolysiloxane may be linear, 
branched, or cyclic, but may more preferably be linear to make the 
addition polymerization smoothly proceed. 
This organohydrogenpolysiloxane contains in its molecule not less than 1.5, 
and preferably 2 to 5, silicon-bonded hydrogen atoms (Si-H bonds) on 
average. 
The silicon-bonded hydrogen atoms in the molecule preferably comprise from 
0.5 to 50 mol %, and more preferably from 1 to 20 mol % of the total of 
the silicon-bonded hydrogen atoms and organic groups. 
The organic groups (represented by R in the above) contained in the 
component (A) can include various groups, but are preferably the methyl 
group, and it is particularly preferred that not less than 50 mol % of R's 
is comprised of the methyl group. 
Typical examples of the organohydrogenpolysiloxane of (A) include a 
compound represented by the formula: 
EQU [(CH.sub.3).sub.3 SiO.sub.0.5 ].sub.a [(CH.sub.3).sub.2 HSiO.sub.0.5 
].sub.b [(CH.sub.3).sub.2 SiO].sub.c [CH.sub.3 HSiO].sub.d, 
wherein a and b are each an integer of from 0 to 2, provided that a+b=2, c 
is an integer of from 0 to 500, and d is an integer of from 0 to 50. 
(B) Organopolysiloxane 
The organopolysiloxane of (B) contains in its molecule not less than 1.5, 
and preferably from 2 to 5, silicon-bonded aliphatic unsaturated groups on 
average. The aliphatic unsaturated group includes, for example, a vinyl 
group and an allyl group, but, in general, preferably a vinyl group. This 
organopolysiloxane includes, for example, those comprising some or all of 
an (CH.sub.2 .dbd.CH)SiO.sub.1.5 unit an RSiO.sub.1.5 unit, an R(CH.sub.2 
.dbd.CH)SiO unit, an R.sub.2 SiO unit, an R.sub.2 (CH.sub.2 
.dbd.CH)SiO.sub.0.5 unit and an R.sub.3 SiO.sub.0.5 unit (wherein R is as 
defined above). 
The aliphatic unsaturated groups preferably comprise from 0.5 to 50 mol %, 
and more preferably from 1 to 20 mol %, of all the organic groups bonded 
to silicon atoms. The organic groups other than the aliphatic unsaturated 
groups are preferably the methyl group. It is particularly preferred that 
the methyl group comprises not less than 50 mol % of the organic groups 
other than the aliphatic unsaturated groups. 
The molecular structure of the organopolysiloxane of (B) may be linear, 
branched or cyclic, but is more preferably linear to make the addition 
polymerization smoothly proceed. 
Typical examples of the organopolysiloxane of (B) include a 
methylvinylpolysiloxane represented by the formula: 
EQU [(CH.sub.2 .dbd.CH)(CH.sub.3).sub.2 SiO.sub.0.5 ].sub.e [(CH.sub.3).sub.3 
SiO.sub.0.5 ].sub.f 
EQU [(CH.sub.3).sub.2 SiO].sub.g [(CH.sub.2 .dbd.CH)CH.sub.3 SiO].sub.h 
wherein e and f are each an integer of from 0 to 2, provided that e+f=2, g 
is an integer of from 0 to 500, and h is an integer of from 0 to 50. The 
organopolysiloxanes can be used singly or in combination of two or more. 
As described above, in both of the anohydrogenpolysiloxane of (A) and the 
anopolysiloxane of (B), the number of the reactive groups, i.e., the 
silicon-bonded hydrogen atoms or aliphatic unsaturated groups, 
respectively, in the molecule is required to be not less than 1.5 on 
average. The number otherwise less than 1.5 for any one of them makes it 
difficult to form the three-dimensional structure in the polymer formed by 
addition polymerization. 
The silicon-bonded hydrogen atoms and the silicon-bonded aliphatic 
unsaturated groups are preferably contained in an amount of from 0.8 to 50 
mol % in the organohydrogenpolysiloxane of (A) and the organopolysiloxane 
of (B), respectively. If the content of either of these reative groups is 
more than 50 mol %, the polymer formed will have an excessively high 
crosslink density in the three-dimensional structure, so that the 
low-viscosity silicone oil of (C) can be incorporated into the 
three-dimensional structure with difficulty. As the result, the 
incorporation of the low-viscosity silicone oil is unstable and the oil 
may readily bleed on the surface of the polymerization product. On the 
other hand, if the content of either of the reactive groups is less than 
0.5 mol %, the three-dimensional structure is formed in the polymer with 
difficulty. 
In a more preferred embodiment, at least one of the 
organohydrogenpolysiloxane of (A) and the organopolysiloxane of (B) 
contains the reactive group, i.e.. the silicon-bonded hydrogen atoms or 
the silicon-bonded aliphatic unsaturated groups, in an amount smaller than 
20 mol %. In this preferred embodiment, the degree of crosslinking of the 
polymer obtained is brought into a suitable state, and thus it is possible 
to obtain a composition that may cause the low-viscosity silicone of (C) 
to be incorporated in the polymer without bleeding out on the surface of 
the polymer. Consequently, the polymerization product of Component (I) can 
be obtained in the form of powder which is easy to work. 
(C) Low-viscosity Silicone Oil 
As the low-viscosity silicone oil of (C) used in this invention, any 
silicone oil can be used without any particular limitation so long as it 
has a viscosity of not more than 100 cSt at 25.degree. C., preferably not 
more than 10 cSt. The use of a silicon oil having a viscosity of more than 
100 cSt at 25.degree. C. makes it difficult for the silicone oil to be 
retained in the three-dimensional structure of the polymer formed by the 
addition polymerization, and the silicon oil bleeds on the surface of the 
polymer. Thus, a uniform polymerization product can not be obtained. 
The low-viscosity silicone oil may be linear, branched or cyclic. Examples 
of the low-viscosity silicone oil include siloxanes with a low degree of 
polymerization, including linear or branched ones such as 
methylpolysiloxane, methylphenylpolysiloxane, ethylpolysiloxane, 
ethylmethylpolysiloxane and ethylphenylpolysiloxane, and cyclic ones such 
as octamethylcyclotetrasiloxane and decamethyIcyclopentasiloxane. One or 
more of them can be used under appropriate selection as desired. 
Polymerization Conditions 
The powder of the polymerization product of Component (I), which is used 
for production of the polishing agent of this invention, is prepared by 
subjecting the organohydrogenpolysiloxane of (A) and the 
organopolysiloxane of (B) to addition polymerization in the presence of 
the low-viscosity silicone oil of (C) under stirring. Here, the 
low-viscosity silicone oil is used in the amount ranging from 10 to 200 
parts by weight, and preferably ranging from 20 to 100 parts by weight, 
based on 100 parts by weight of the total amount of the 
organohydrogenpolysiloxane of (A) and the organopolysiloxane of (B). If 
the amount of the low-viscosity silicone oil is less than 10 parts by 
weight, the polymerization product formed is hard and thereby incapable of 
thickening the low viscosity-silicon oil of Component (II), which is 
described later, to produce a polishing agent with a desired viscosity. If 
the amount of the low-viscosity silicone oil of (C) is over 200 parts by 
weight, it may bleed on the surfaces of the polymerization product, which 
is difficult to handle. 
The organohydrogenpolysiloxane of (A) and the organopolysiloxane of (B) may 
be used in the above addition polymerization preferably in the range of 
the proportion such that the molar ratio of the silicon-bonded hydrogen 
atoms possessed by (A) to the silicon-bonded aliphatic unsaturated groups 
possessed by (B) is from 1/3 to 3/1, and more preferably from 1/2 to 2/1. 
If the above molar ratio is outside the range from 1/3 to 3/1, the 
stability of the polymerization product obtained may be impaired because 
unreacted components (i.e., silicon-bonded hydrogen atoms or 
silicon-bonded aliphatic unsaturated groups) remain therein. 
The production of the polymerization product by the addition polymerization 
may be operated by, for example, in a reaction vessel such as a planetary 
mixer equipped with a suitable stirrer, charging the organohydrogen 
polysiloxane of (A), the organopolysiloxane of (B) and the low-viscosity 
silicone oil of (C), followed by further addition of a catalyst, and 
stirring the mixture at an appropriate temperature of from about 
50.degree. to about 150.degree. C. As the polymeization proceeds, the 
reaction mixture gradually increase its viscosity, thereby turning from a 
liquid state through a soft mass, which is disintegrated, finally to a 
powdery state. 
As the catalyst, a platinum compound or rhodium compound is used. The 
platinum compound includes, for example, chloroplatinic acid, 
alcohol-modified chloroplatinic acid, a chloroplatinic acid-vinylsiloxane 
complex, the platinum compounds used in hydrosilylation reaction as 
described in U.S. Pat. Nos. 3,159,601, 3,159,662 and 3,775,452, etc., 
which preferably include, for example, a complex compound of vinylsiloxane 
with a platinum compound, and further the same having been modified with 
alcohol. Among these, particularly preferred are the chloroplatinate 
described in Japanese Patent Publication (KOKOKU) No. 9969/1958, and a 
complex compound of vinylsiloxane with chloroplatinate. 
The powder of the polymerization product thus obtained can be mixed as it 
is as a main component of the polishing agent with the low-viscosity oil 
of (II). However, before mixed with the oil of (II), the powder is 
preferably ground into fine powder by means of a grinding unit capable of 
applying shearing force, for example, a three-roll mill, a two-roll mill 
and a sand grinder. 
The powder of the polymerization product of (I) is a white powder, free 
from any bleeding of the low-viscosity silicone oil of (C) on the surface, 
having a dry feeling, having a smooth feel, and provided with an 
appropriate degree of softness. 
Component (II) 
The polishing agent of this invention comprises a composition prepared by 
mixing (I) the powder of the polymerization product with (II) the 
low-viscosity oil having a viscosity of not more than 10 cSt at 25.degree. 
C. 
The kind of the low-viscosity oil of (II) is not limited, as long as the 
oil has a viscosity of not more than 10 cSt at 25.degree. C. The oil 
having a viscosity of more than 10 cSt at 25.degree. C. can not be mixed 
uniformly with said Component (I), the powder of the polymerization 
product, thereby producing a composition having poor coverability or 
spreadability and having a sticky feel. 
The low-viscosity oil includes, for example, siloxanes with a low degree of 
polymerization, including linear or branched ones such as 
methylpolysiloxane, methylphenylpolysiloxane, ethylpolysiloxane, 
ethylmethylpolysiloxane, ethylphenylpolysiloxane, and cyclic ones such as 
octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane; aliphatic 
hydrocarbon oils with a low viscosity such as ligroin, mineral spirit, 
kerosene, and isoparaffins. These may be used singly or in combination of 
two or more. 
Preparation of Polishing Agent 
The composition, the main ingredient of the polishing agent of this 
invention, can be prepared by mixing the low-viscosity oil of (II) with 
the polymerization product powder of (I) uniformly, optionally under 
heating at from 50.degree. to 150.degree. C., in a container equipped with 
a suitable stirrer, e.g., a planetary mixer. 
The polishing agent of this invention usually contains, as a main 
ingredient, 50% by weight or more of the composition prepared as above. 
The polishing agent may optionally contain other gredients, for example. 
natural waxes such as carnauba wax, montan wax and beeswax; synthetic 
waxes such as Hoechst wax (supplied by Hoechst AG), Hiwax (supplied by 
Mitsui Petrochemical Industries. Ltd.). Castor wax (supplied by Kokura 
Gosei Kogyo K.K.) and San wax (supplied by Sanyo Chemical lndustries, 
Ltd.); silicone oils such as methyl silicone oils, methylphenylsilicon 
oils, amino-modified silicones and fluorine-modified silicones; abrasive 
materials such as diatomaceous earth, silica and silicates; stabilizing 
agents; prefumes: dyes: and pigments. 
EXAMPLES 
This invention will be further described by way of Examples. These, 
however, by no means limit this invention. Viscosity set out below referes 
to the viscosity at 25.degree. C., and "part(s)" denotes part(s) by 
weight. 
Preparation Example 1 
In a planetary mixer with an internal volume of about 5 liter, 650 % of 
trimethylsilyl-terminated dimethylmethylhydrogenpolysiloxane (average 
molecular weight:2.180; Si-H content:6.5 mol %), 549 % of 
dimethylvinylsilyl-terminated dimethylpolysiloxane (average molecular 
weight:930; vinyl group content:7.7 mol %) and 800 % of 
octamethylcyclotetrasiloxane (viscosity:2.3 cSt) were charged, stirred and 
mixed. In the resulting mixed solution, 0.5 % of a 2 % chloroplatinic acid 
solution in 2-propanol was added, and stirring was continued at 70.degree. 
to 80.degree. C. for 2 hours. A powdery white product endowed with 
softness was obtained. The powder product was ground by means of a 
three-roll mill to give a uniform white a powder (1). 
The powder (1) has a particle diameter of about 100 to 500 .mu.m, and has 
dry surfaces and a soft feel. 
Preparation Example 2 
In a planetary mixer with an internal volume of about 5 liter, 880 % of 
trimethylsilyl-terminated dimethylmethylhydrogenpolysiloxane (average 
molecular weight:2,340; Si-H content:4.5 mol %), 512 % of 
dimethylvinylsilyl-terminated dimethylpolysiloxane (average molecular 
weight:930; vinyl group content:7.7 mol %) and 597 g of 
phenyltris(trimethylsiloxy)silane (viscosity:3.8 cSt) were charged, 
stirred and mixed. In the resulting mixed solution, 0.5 % of a 2 % 
chloroplatinic acid solution in 2-propanol was added, and thereafter the 
same procedure as in Preparation Example 1 was repeated to produce a white 
powder (2). 
Preparation Example 3 
In a planetary mixer with an internal volume of about 5 liter, 660 % of 
dimethylhydrogensilyl-terminated dimethylpolysiloxane (average molecular 
weight:1,020; Si-H content:6.7 mol %), 1,135 g of 
trimethylsilyl-terminated dimethylmethylvinylpolysiloxane (average 
molecular weight:2.640; vinyl group content:4.2 mol %) and 199 g of 
trimethylsilyl-terminated dimethylpolysiloxane (viscosity:6 cSt) were 
charged, stirred and mixed. In the resulting mixed solution, 0.5 g of a 2 
% chloroplatinic acid solution in 2-propanol was added, and thereafter the 
same procedure as in Preparation Example 1 was repeated to produce a white 
powder (3). 
Examples 1 to 5 
In each example, in a planetary mixer with a internal volume of 5 liter, a 
low-viscosity oil and an additive were charged as given in Table I, and 
then mixed by stirring under heating at 80.degree. C. to form a uniform 
mixture. Subsequently, while stirring was continued, the powder (1), (2) 
or (3) obtained in the above Preparation Examples was added. The mixture 
was stirred at 80.degree. C. for another one hour, and thereafter cooled 
to room temperature under stirring a polishing agent was thus prepared. 
The viscosity of the polishing agents obtained was measured. The results 
are given in Table 1. 
The polishing agents obtained in the Examples were all in the form of 
uniform and white paste. They exhibited markedly good spreadability when 
applied on painted steel plate. After left to stand for about 30 min., the 
applied polishing agent could be readily wiped off. The resulting surface 
had a coating excellent in water repellency and brightness. 
The surface-treated painted steel plates thus obtained were left to stand 
outdoors for two months. However, the steel plates all retained water 
repellency at the same level as before. 
TABLE 1 
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Powder Viscosity of 
Low-Viscosity oil of polymerization 
Additive polishing 
Amount 
Product 
Amount Amount 
agent 
Example 
Kind (part) 
No. (part) 
Kind (part) 
(cP), 25.degree. C. 
__________________________________________________________________________ 
1 Octomethylcyclo- 
67 (1) 30 KF96.sup.1) (500 cSt) 
3 52000 
tetrasiloxane 
2 Octomethylcyclo- 
68 (1) 27 KF96 (500 cSt) 
3 23000 
tetrasiloxane Carnauba wax (No. 2) 
2 
3 Phenyltris(trimethyl- 
36 (2) 23 KF96 (100 cSt) 
2 2100 
siloxy)silane Carnauba wax (No. 2) 
3 
Isoper M.sup.2) 
36 
4 IP Solvent 2028.sup.3) 
67 (3) 30 KF96 (1000 cSt) 
3 65000 
5 Octomethylcyclo- 
50 (3) 25 Carnauba wax (No. 2) 
4 58000 
tetrasiloxane 
Diphenylhexa- 
21 
methyltrisiloxane.sup.4) 
__________________________________________________________________________ 
Remarks: 
.sup.1) Dimethylpolysiloxane supplied by ShinEtsu Chemical Co., Ltd. 
.sup.2) Isoparaffin (Viscosity: 3.1 cSt) supplied by Exxon Chemical Co., 
Ltd. 
.sup.3) Isoparaffin (Viscosity: 3.4 cSt) supplied by Idemitsu 
Petrochemical Co., Ltd. 
.sup.4) Viscosity: 7.5 cSt 
Comparative Example 1 
A polishing agent was prepared in the same manner as in Example 1 except 
that dimethylpolysiloxane (KF96, 20 cSt, product of Shin-Etsu Chemical 
Co., Ltd.) was used as the low-viscosity oil. 
The powder (1) was not swelled uniformly, and the polishing agent has a low 
viscosity of 280 cP. 
Comparative Example 2 
Powder (4) was prepared in the same manner as in Preparation Example 1, 
except that the octomethylcyclotetrasiloxane was not used. 
Subsequently, a polishing agent was prepared in the same manner as in 
Example 1, except that the powder (1) was replaced with the powder (4). 
The powder (4) was not swelled uniformly, and the polishing agent obtained 
had a low viscosity of 120 cP. 
Comparative Example 3 
Preparation of a powder was attempted in the same manner as in Preparation 
Example 2, except that the amounts of the trimethylsilyl-terminated 
dimethylmethyl hydrogenpolysiloxane, the dimethylvinylsilyl-terminated 
dimethylpolysiloxane, and the phenyltris (trimethylsiloxy) silane were 
changed to 302 g, 176 g and 1,202 g, respectively. The resulting product 
was not a powder but an solid mass of irregular shape. 
Subsequently, a polishing agent was prepared in the same manner as in 
Example 1, except that the powder (1) was replaced with the above solid 
mass. 
The viscosity of the polishing agent obtained was measured to be as high as 
43,000 cP, but the polishing agent contains gel-like residual substances 
and therefore lacked uniformity.