JPH0561308B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to an organopolysiloxane composition that has excellent heat resistance and does not cause separation or precipitation of cerium compounds even when it comes into contact with rubber at high temperatures. [Description of Prior Art] In heat fixing devices for electronic copying machines, rubbers such as chloroprene rubber, nitrile rubber, isoprene rubber, butadiene rubber, ethylene propylene rubber, ethylene propylene diene rubber, butadiene acrylonitrile rubber, ethylene acrylic rubber, and silicone rubber are used. However, this type of rubber roll has insufficient releasability against toner, etc., and to improve its releasability, it is generally heated in dimethylpolysiloxane oil at 180°C and 24°C.
Impregnation treatment is carried out for about an hour (Tokukō Sho 58-
(See Publication No. 36337). However, dimethylpolysiloxane oil has poor thermal stability at high temperatures, so each time it is impregnated,
It had the disadvantage that new dimethylpolysiloxane oil had to be used. In addition, in recent years, dimethylpolysiloxane oil to which a cerium compound is added has been proposed as a heat-resistant oil (Japanese Patent Publication No. 51-24377, Japanese Patent Publication No. 53-980, Japanese Unexamined Patent Publication No. 51-66344, (Refer to Publication No. 1983-32563). However, these cerium compound-containing dimethylpolysiloxane oils exhibit good thermal stability when used alone, but when used at high temperatures around 200°C, they are resistant to chloroprene rubber, nitrile rubber, isoprene rubber, butadiene rubber, ethylene propylene rubber, ethylene propylene diene rubber, When it comes into contact with rubber such as butadiene rubber, acrylonitrile rubber, ethylene acrylic rubber, silicone rubber, etc., the cerium compound separates and precipitates, and the heat resistance is almost the same as that of general dimethylpolysiloxane oil. It had the disadvantage that the effect of its blending was hardly exhibited. In addition, these dimethylpolysiloxane oils, especially the dimethylpolysiloxane oil described in JP-A-54-32563, are manufactured by adding a small amount of methylhydrodienepolysiloxane.
It is necessary to heat the product to 230 to 250°C and blow air into it (air ration treatment), and if this air ration treatment is not performed, it will become colored and cannot be used for some purposes. [Object of the invention] In order to solve the above-mentioned drawbacks, the present invention is characterized by adding and blending an organohydrodiene polysiloxane and an alkoxy group-containing titanium compound to an organopolysiloxane containing a cerium compound. , nitrile rubber,
An organopolymer that does not separate or precipitate cerium compounds even when it comes into contact with rubbers such as isoprene rubber, butadiene rubber, ethylene propylene rubber, ethylene propylene diene rubber, butadiene rubber, acrylonitrile rubber, ethylene acrylic rubber, silicone rubber, etc. An object of the present invention is to provide a siloxane composition. Another object of the present invention is to provide an organopolysiloxane composition that does not become colored, thickened, or even gelled when heated. [Description of structure and operation of the invention] The present invention provides the following features: (a) Average compositional formula

Organopolysiloxane represented by the formula: (wherein R is a monovalent organic group and a is a number from 1 to 3)
100 parts by weight, (b) cerium chloride, a reaction product of an alkali metal silanolate having three or more organosiloxane units, 0.001 to 10 parts by weight, (c) an organosiloxane having at least one silicon-bonded hydrogen atom in one molecule Hydrodiene Polysiloxane The blending amount of this component is such that the content of silicon-bonded hydrogen atoms in the composition is 10 to 10%.
and (ii) an alkoxy group-containing titanium compound in an amount of 10,000 ppm. To explain this, component (a) organopolysiloxane used in the present invention is the main component of the present composition, and in the above average composition formula, R is a monovalent organic group. These include, for example, alkyl groups such as methyl, ethyl, propyl, and butyl; substituted alkyl groups such as 2-phenylethyl, 2-phenylpropyl, and 3,3,3-trifluoropropyl; Examples thereof include aryl groups and substituted aryl groups such as a propenyl group, a propenyl group, and a tolyl group. a is a number from 1 to 3 on average.
The molecular structure of this organopolysiloxane is not particularly limited, and any viscosity and degree of polymerization can be selected depending on the purpose and use. The end groups of these organopolysiloxanes are
A trialkylsilyl group, an alkoxy group, a hydroxyl group or a vinyl group is preferred. The organopolysiloxanes include trimethylsilyl end-blocked dimethylpolysiloxane, dimethylvinylsilyl end-blocked dimethylpolysiloxane, dimethylallylsilyl end-blocked dimethylpolysiloxane, phenylmethylvinylsilyl end-blocked methylphenylsiloxane/dimethylsiloxane. Copolymers, trimethylsilyl-terminated methylphenylpolysiloxanes, silanol-terminated dimethylpolysiloxanes, dimethylmethoxysilyl-terminated dimethylpolysiloxanes, vinylpolysilsesquioxanes, copolymers consisting of trimethylsiloxane units and SiO _4/2 units. Examples include polymers. The reaction product of component (b), cerium chloride, and an alkali metal silanolate having three or more organosiloxane units used in the present invention is necessary for imparting thermal stability at high temperatures to organopolysiloxane. It is a component. Here, as the alkali metal silanolate,
For example, there are potassium silanolate, sodium silanolate, and such alkali metal silanolates are described in, for example, WTGrubb, RCOstoff, J.
ACS, 77 , 1405 (1955), or by combining an alkali metal silanolate with a silanol group at both ends of the organopolysiloxane molecular chain obtained in this way and a linear organopolysiloxane. It is obtained by a method of reacting the silanolates to form an alkali metal silanolate having a silanol group at only one end of the molecule. Examples of the organic group bonded to the silicon atom in the alkali metal silanolate include the organic groups exemplified for R in component (a). The reaction product of cerium chloride and an alkali metal silanolate having three or more organosiloxane units is obtained by combining cerium chloride and the alkali metal silanolate with an alcohol such as ethanol, isopropanol, or butanol, or with an aromatic compound such as benzene or toluene. By using a mixture of as a solvent and reacting at room temperature and heating to reflux temperature if necessary, the solvent is then distilled off, and if necessary, the formed precipitate can be obtained by filtration ( (See Special Publication No. 53-980). In this case, it is preferable that cerium chloride be reacted in an anhydrous state by appropriate dehydration treatment. The blending amount of this component is based on 100 parts by weight of component (A).
It is 0.001 to 10 parts by weight. Component (c) organohydrodiene polysiloxane is an essential component to suppress separation and precipitation of cerium compounds when it comes into contact with rubber at high temperatures, and contains at least one silicon in each molecule. It has an atomically bonded hydrogen atom. The organohydrodiene polysiloxane may be composed only of organohydrodiene siloxane units, or may contain hydrogen siloxane units or organosiloxane units. Other organic groups bonded to silicon atoms include alkyl groups such as methyl, ethyl, and propyl groups; 2
-phenylethyl group, 2-phenylpropyl group,
Examples include substituted alkyl groups such as 3,3,3-trifluoropropyl group; aryl groups or substituted aryl groups such as phenyl group and tolyl group.
The structure of the organohydrodiene polysiloxane is not particularly limited, and may be linear, cyclic, or branched. Although the viscosity is not particularly limited, the viscosity at 25° C. is preferably in the range of 5 to 10,000 centistokes for ease of blending with other components. Organohydrodiene polysiloxanes include dimethylhydrogensilyl group end-blocked dimethylsiloxane/methylhydrodienesiloxane copolymer, trimethylsilyl group endblocked dimethylsiloxane/methylhydrogensiloxane copolymer, and dimethylphenylsilyl group endblocked dimethylsiloxane. Examples include methylhydrogensiloxane copolymer, trimethylsilyl end-blocked methylhydrogenpolysiloxane, and cyclic methylhydrogenpolysiloxane. The amount of this component is such that the content of silicon-bonded hydrogen atoms in the composition is 10 to 10,000 ppm. The alkoxy group-containing titanium compound used in the present invention as component (2) functions to improve the thermal stability of the composition of the present invention. Examples of such titanium compounds include n-butyl alkoxy compounds of titanium, exemplified by tetrabutyl titanate and condensates of the tetrabutyl titanate. The blending amount of this component is 0.001 per 100 parts by weight of component (A).
-1 part by weight. The composition of the present invention may also include metal salts of organic carboxylic acids such as zirconium naphthenate and iron naphthenate; isopropylalkoxy compounds of zirconium; inorganic fillers such as dry silica, wet silica, diatomaceous earth, and powdered quartz; metal soaps; Pigments and the like may also be added. In addition to inorganic fillers, organic peroxide vulcanizing agents such as benzoyl peroxide,
2,4-dichlorobenzoyl peroxide, t
- Thermal stabilization is achieved by blending butyl peroxide, etc., or by blending a crosslinking agent such as a silicate ester, triacetoxysilane, or trioxime silane with an inorganic filler, and a curing catalyst such as a tin salt of a fatty acid or a platinum compound. It is also possible to form thermosetting or room temperature curable silicone rubber compositions with excellent properties. [Example] Next, the present invention will be explained in detail according to an example.
In the examples, viscosity is a measured value at 25°C. Example 1 WTGrubb, RCOstoff, Journal of the
60 g of potassium silanolate synthesized from potassium hydroxide, hexamethylcyclotrisiloxane, and octamethylcyclotetrasiloxane by the method described in American Chemical Society 77 , 1405 (1955) was capped with trimethylsilyl groups at both ends and had a viscosity of 20 centistokes. of dimethylpolysiloxane and hexamethylphosphoramide,
0.5 g was added and reacted for 2 hours at 115° C. under a nitrogen stream. Dissolve 100 g of this reaction mixture in 150 g of isopropanol, and add 2.5 g of anhydrous cerium chloride to a mixed alcohol solution (50 g of ethanol).
and 50 g of methanol) was added dropwise with stirring. The reaction mixture was filtered and then reduced under reduced pressure.
The solvent was distilled off at 40-50°C. The filtrate was filtered again to remove a small amount of precipitate, yielding a pale yellow liquid reaction product. The cerium concentration in this reaction product was 0.8% by weight. Next, 20g of dimethylpolysiloxane with a viscosity of 100 centistokes was weighed into a 100ml beaker, and 0.2g of the liquid reaction product obtained above, 0.005g of tetrabutyl titanate (tetra-n-butyl orthotitanate) and the viscosity 0.01 g of 20 centistokes methylhydrodiene polysiloxane (the amount of methyl groups is 50 mol% based on the total amount of substituents)
and mixing at room temperature to prepare an organopolysiloxane composition. Next, an organic peroxide vulcanized silicone rubber sheet (2 cm square, 2 mm thick) was immersed in this organopolysiloxane composition and left in a hot air circulation oven at 200°C to observe changes in appearance. . The results are shown in Table 1. Example 2 A platinum compound-catalyzed addition-curing silicone rubber sheet (2 cm square, 2 mm thick) was immersed in the organopolysiloxane composition prepared in Example 1, and heated in a hot air circulation oven at 200°C for 2 hours. I left it for days. After taking out the silicone rubber sheet, the organopolysiloxane composition was left in a hot air circulation oven at 300°C, and the number of days until gelation was determined was determined. The results are shown in Table 2. Example 3 30g of the organopolysiloxane composition obtained in Example 1 was placed in a 100ml beaker, left in a hot air circulation oven at 250°C, the change in viscosity was measured after 500 hours, and the result was calculated as the change in viscosity. It is shown in Table 3 as a percentage. Comparative Example 1 Cerium octylate (cerium concentration 6%), 25 g of hexamethylsilazane, and 5 g of water were added to 150 g of xylene, mixed at room temperature for 2 hours, and reacted for 2 hours under reflux of xylene, and unreacted water was removed. It was distilled off as an azeotrope with xylene.
Next, 300 g of dimethylpolysiloxane having a viscosity of 20 centistokes and capped with trimethylsilyl groups at both ends was added, and then xylene was distilled off under reduced pressure to obtain a yellow liquid reaction product. The cerium concentration of this reaction product was 0.2% by weight. Weigh out 20 g of dimethylpolysiloxane with a viscosity of 100 centistokes into a 100 ml beaker, add 0.8 g of the liquid reaction product obtained above and 20 g of the liquid reaction product with a viscosity of 20 centistokes.
An organopolysiloxane composition was prepared by adding 0.01 g of Centistoke's methylhydrodiene polysiloxane (the amount of methyl groups is 50 mol % based on the total amount of substituents) and mixing at room temperature. The properties of this composition were measured in the same manner as in Examples 1 and 2. These measurement results are also listed in Tables 1 and 2, respectively. Comparative Example 2 An organopolysiloxane composition was prepared in the same manner as in Example 1 except that methylhydrodiene polysiloxane was not added. The properties of this composition were measured in the same manner as in Examples 1 and 2. These measurement results are also listed in Tables 1 and 2, respectively. Comparative Example 3 An organopolysiloxane composition was prepared in the same manner as in Example 1, except that tetrabutyl titanate was not added. The properties of this composition were measured in the same manner as in Examples 1, 2 and 3. These measurement results are also listed in Table 1, Table 2, and Table 3, respectively.

【table】

【table】

[Table] Viscosity change rate = (viscosity after 500 hours - initial viscosity) / initial viscosity x 100 [Explanation of effects] The organopolysiloxane composition of the present invention has excellent heat resistance, so the increase in viscosity at high temperatures is small. ,
It is difficult to gel and has the characteristic that the cerium compound does not separate or precipitate, especially when it comes into contact with rubber at high temperatures. Therefore, the composition of the present invention can be suitably used as a heating medium, a high-temperature transformer, an impregnating oil for rubber for rubber rolls, rolling, etc., a damper oil, an oil for fan clutches, and the like. Silicone greases and silicone compounds can also be produced by adding a thickener such as metal soap or a filler such as silica to the organopolysiloxane composition of the present invention as a base oil.

Claims (1)

[Claims] 1 (a) An organopolysiloxane represented by the average compositional formula [Formula] (wherein R is a monovalent organic group and a is a number from 1 to 3)
100 parts by weight, (b) 0.001 to 10 parts by weight of a reaction product of cerium chloride and an alkali metal silanolate having three or more organosiloxane units, (c) At least one silicon-bonded hydrogen atom in one molecule Organohydrodiene polysiloxane The blending amount of this component is such that the content of silicon-bonded hydrogen atoms in the composition is 10 to 10%.
and (d) an alkoxy group-containing titanium compound in an amount such that the amount is 10,000 ppm.
An organopolysiloxane composition comprising 0,001 to 1 part by weight.