JPH0662851B2 - Hardened silicone powder containing silicone oil - Google Patents

Description

The present invention relates to a silicone oil-containing silicone powder granule,
In particular, it relates to a silicone oil-containing silicone powder granule that can be suitably used as an additive for modifying physical properties of various materials such as various rubbers, organic resins and lubricating oils.

[Conventional technology and its problems]

In recent years, silicone oil has been widely used as an internal lubricity imparting agent for various organic resins, a surface lubricity imparting agent, an abrasion resistance improving agent, and an impact strength improving agent. Further, silicone powder granules have begun to be used as internal stress relieving agents for various organic resins and as water resistance improvers.

However, these silicone oils have a poor affinity to organic resins, which are essentially different materials, and a special device is used or a kneading method is devised in order to uniformly mix and disperse these in the organic resin. Was necessary. In addition, when a normal extrusion molding machine or a screw-type injection molding machine is used for molding, it is difficult to obtain a molded product in which silicone oil is uniformly dispersed without slipping the silicone oil into the molding machine. There was a problem.

On the other hand, although silicone powder granules can be dispersed in various organic resins relatively easily, they do not exhibit the effect of imparting internal lubricity, the effect of improving wear resistance, and the effect of improving impact resistance as silicone oil does. However, its use has been limited as an additive for modifying physical properties of various materials such as various rubbers, organic resins, and lubricating oils. The present inventors have arrived at the present invention as a result of intensive research to solve the above problems.

An object of the present invention is to provide a silicone powder granule having excellent lubricity and impact absorption, and is preferably used as an additive for modifying physical properties of various materials such as various rubbers, organic resins and lubricating oils. The present invention provides a novel silicone powder granule.

[Structure of Invention and Its Action]

The present invention is a cured silicone powder granule having an average particle size of 0.1 to 20000 μm containing 0.5 to 80% by weight of silicone oil, wherein the cured silicone is prepared by heating and curing an organopolysiloxane or an organopolysiloxane composition. The obtained cured product is a cured silicone powder containing silicone oil, wherein the silicone oil is uniformly dispersed in the cured silicone powder.

To explain, the silicone oil used in the present invention is a liquid organopolysiloxane having a siloxane bond (—Si—O— bond) in its main chain, and its type is not particularly limited.

Examples of such silicone oils are those represented by the general formula R ₃ SiO [R ₂ SiO] _n SiR ₃ (wherein R is a substituted or unsubstituted monovalent hydrocarbon group or hydroxyl group, and n is an integer). There is a liquid organopolysiloxane represented. In the above formula, R is an alkyl group such as a methyl group, an ethyl group or a propyl group; an alkenyl group such as a vinyl group or an allyl group; an aralkyl group such as a cycloalkyl group or a β-phenylethyl group;
A substituted or unsubstituted monovalent hydrocarbon group exemplified by a 3,3-trifluoropropyl group, a 3-mercaptopropyl group, a 3-aminopropyl group, a 3-glycidoxypropyl group and the like.

Specific examples of such silicone oil include, for example, dimethylpolysiloxane whose both molecular chain ends are blocked with trimethylsiloxy groups, dimethylsiloxane-methylphenylsiloxane copolymer whose both molecular chain ends are blocked with trimethylsiloxy groups, and molecules. Dimethylsiloxane-diphenylsiloxane copolymer with both chain ends blocked with trimethylsiloxy groups, dimethylsiloxane-methyl (3,3,3-trifluoropropyl) siloxane copolymer with both chain ends blocked with trimethylsiloxy groups Examples include dimethylpolysiloxane having a 3-mercaptopropyl group at the molecular chain end and / or the molecular chain side chain, and dimethylpolysiloxane having a 3-glycidoxypropyl group at the molecular chain end and / or the molecular chain side chain. .

The molecular weight of the silicone oil is not particularly limited as long as it is liquid, but the viscosity at 25 ° C. is preferably within the range of 100 to 10,000 centistokes, and particularly preferably within the range of 100 to 10,000 centistokes.

Further, the content of silicone oil must be in the range of 0.5 to 80% by weight, and preferably in the range of 1 to 60% by weight. When it is less than 0.5% by weight, the silicone oil does not migrate from the inside of the silicone powder granules to other various materials, and the effect as a physical property modifier decreases, and when it exceeds 80% by weight, the silicone powder granules This is because the amount of silicone oil contained in 1 reaches saturation.

The silicone powder granules of the present invention must contain the above silicone oil and have a particle size of 0.1 to 20000 μm. This is because when the average diameter is less than 0.1 μm, the effect of modifying physical properties of various materials decreases.
This is because if it exceeds 0 μm, it becomes difficult to add and blend it into various materials.

Conventionally known silicone rubber can be used as the silicone forming the silicone powder granules. For example, an organic peroxide-curable silicone rubber obtained by curing a vinyl group-containing diorganopolysiloxane with an organic peroxide,
Silicone-bonded vinyl group-containing diorganopolysiloxane and silicon-bonded hydrogen atom-containing organopolysiloxane are subjected to an addition reaction in the presence of a platinum-based compound catalyst to cure, and an addition reaction-curable silicone rubber is attached to both ends of the molecular chain. A condensation reaction curable silicone rubber obtained by dehydrogenating a diorganopolysiloxane having a hydroxyl group and an organopolysiloxane having a silicon atom-bonded hydrogen atom in the presence of an organotin compound and curing the same. There is a condensation reaction-curable silicone rubber obtained by subjecting an organopolysiloxane and a hydrolyzable organosilane to a condensation reaction in the presence of an organotin compound or titanic acid esters. In the present invention, the latter two types, that is, the addition reaction curable silicone rubber and the condensation reaction curable silicone rubber, are preferable because they are easy to produce and easy to handle.

As the silicone forming the silicone powder granules, conventionally known silicone gel can be used. This is a silicone containing an organopolysiloxane as a main component, which is partially three-dimensionally reticulated by cross-linking and shows deformation and limited fluidity by the application of stress, and usually has a hardness of 50 or less in an Asuka C hardness tester, The hardness in the JIS hardness tester is 0.

Examples of the method for producing the silicone oil-containing silicone powder granules of the present invention include the following methods.

(1) Organopolysiloxane containing at least two alkenyl groups represented by vinyl group in one molecule and organohydrogenpolysiloxane containing at least two hydrogen atoms bonded to silicon atoms in one molecule and platinum system A liquid addition reaction curable silicone rubber composition comprising a compound catalyst is blended with silicone oil to prepare a silicone oil-containing liquid silicone rubber composition, which is then placed in water itself or water containing a surfactant, The water itself or water containing a surfactant is agitated to disperse the water in the form of fine particles to prepare an aqueous dispersion of the liquid silicone rubber composition, and then the aqueous dispersion is sprayed in hot air to obtain the above-mentioned product. The liquid silicone rubber composition is prepared by curing the liquid silicone rubber composition or dispersing the dispersion liquid in water heated to a temperature of 25 ° C. or higher. Obtained by curing the Narubutsu granulated.

(2) Further, it comprises an organopolysiloxane containing at least two hydroxyl groups at both ends of the molecular chain, an organohydrogenpolysiloxane containing at least two hydrogen atoms bonded to silicon atoms in one molecule, and an organotin catalyst. A silicone oil is mixed with a liquid condensation reaction-curable silicone rubber composition to prepare a silicone oil-containing liquid silicone rubber composition, and the composition is placed in water itself or water containing a surfactant, and the water itself or an interface is added. By stirring water containing an activator, the silicone rubber composition is finely dispersed to prepare an aqueous dispersion of a silicone oil-containing liquid silicone rubber composition, and then the aqueous dispersion is left as it is for a long time. Alternatively, it can be obtained by curing the liquid silicone rubber composition by heating, or by spraying in hot air.

The silicone powder granules of the present invention may be used alone or in combination with other materials. When used by itself, it is used as a lubricant, a cushioning agent, an impact absorbing agent, and the like. When used in combination with other materials, the physical properties such as lubricity, wear resistance, impact resistance, water resistance, etc. of various materials added with this can be improved.

In this case, the silicone rubber granules of the present invention can be applied to, for example, the following. That is, solid lubricants, water repellents, release agents, anti-adhesive agents, greases, oils, cements, plasters, paints, casting materials, molding materials, films, agricultural chemicals and medical applications are considered. In addition, examples of the target polymer particularly when mixed and used in a polymer material are silicone rubber, natural rubber, polychloroprene rubber, polybutadiene rubber, SBR, EP.
R, EPT rubber, polyisoprene rubber, polyisopten rubber, polyacrylic ester rubber, polyurethane rubber, butadiene-acrylonitrile copolymer rubber, polyester rubber, polysulfide rubber, fluororubber or copolymer rubber thereof or a mixture of these rubbers. The resin material is nylon-5, nylon-6, nylon-7, nylon-8, nylon-9, nylon-10, nylon-11, nylon-12, nylon-
6.6, various polyamides represented by aromatic polyamides such as Kepler; saturated polyesters represented by polyethylene terephthalate, polybutylene terephthalate, polyhydrogenated xylylene terephthalate, polycaprolactone, polypivalolactone; polycarbonate,
ABS, AS, polystyrene, polyethylene, polypropylene, polybutadiene, polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polymethylmethacrylate, fluorine-containing resin, other polyolefin resin, polyethylene glycol, polypropylene Polyethers such as glycol, polytetrahydrofuran, penton, polyphenylene oxide, polyacetal, phenol resin, polyurethane resin,
Various thermoplastic resins such as acrylic resin, urea resin, unsaturated polyester, melamine resin, phthalic acid resin, BT resin, polyimide resin, silicone resin, celluloid, acetyl cellulose, polyepoxy acrylate, polyacrylate, epoxy resin, etc. Thermosetting resin,
Examples thereof include resins that are cured by high energy rays such as ultraviolet rays, γ rays and electron rays, and block or random copolymers or blends of these resins. Of course, these resins are various inorganic powder fillers, glass fibers, carbon fibers and other fibrous fillers or reinforcing materials,
Heat resistance improver, weather resistance improver and other stabilizers, modifiers,
It goes without saying that it may contain pigments, dyes and the like.

〔Example〕

Next, the present invention will be described with reference to examples. In the examples, “parts” means “parts by weight”, “%” means “% by weight”, and the viscosity is
The value at 25 ° C is shown.

Example 1 Dimethyl polysiloxane with a viscosity of 1000 centistokes, in which both ends of the molecular chain were blocked with hydroxyl groups (hydroxyl group content 1.3
%) 100 parts, methylhydrogenpolysiloxane with a viscosity of 10 centistokes with both molecular chain ends blocked by trimethylsiloxy groups (silicon atom-bonded hydrogen atom content 1.5
%) And 50 parts of dimethylpolysiloxane (hereinafter referred to as dimethylsilicone oil) having a viscosity of 1000 centistokes in which both ends of the molecular chain were blocked with trimethylsiloxy groups as silicone oil (mixture A). Next, 50 parts of dimethyl silicone oil and 1.5 parts of dibutyltin dioctoate were uniformly mixed with 100 parts of dimethylpolysiloxane in which both ends of the same molecular chain were blocked with hydroxyl groups (mixture B). 100 parts of the mixture A and 100 parts of the mixture B were fed into a static mixer [10 elements manufactured by Tokushu Kika Co., Ltd.] and uniformly mixed to obtain a silicone rubber composition containing dimethyl silicone oil. Next, 100 parts of this silicone rubber composition was fed into a colloid mill [mantongori (manufactured by the company)], and at the same time 1700 parts of ion-exchanged water and a surfactant (ethylene oxide adduct of trimethylnonanol, manufactured by Union Carbide Corporation) were used. Add 5 parts of ionic surfactant Taditol TMN-6),
Milling was carried out under the conditions of 00 revolutions / minute and a gap of 0.1 mm to obtain an aqueous dispersion of a silicone rubber composition containing dimethyl silicone oil. Using a spray dryer [made by Myzawaniro Atomizer Co., Ltd.], this water dispersion liquid, the inlet temperature was 300 ° C,
When sprayed into a dryer set at an outlet temperature of 100 ° C., silicone rubber powder granules were obtained.

The obtained silicone rubber powder granules were rubber elastic bodies having good surface lubricity, and when observed with an electron microscope, they were spherical powder granules having an average diameter of 10 μm. Further, when the dimethyl silicone oil contained in this silicone rubber powder granular material was quantified, it contained 45% by weight of dimethyl silicone oil.

Next, a silicone rubber base was prepared by uniformly mixing 100 parts of dimethylpolysiloxane raw rubber having both ends of the molecular chain blocked with dimethylvinylsiloxy groups and 20 parts of fumed silica.

Next, 100 parts of this silicone rubber base was mixed with the dimethyl silicone oil-containing silicone rubber powder granules obtained above and 2.5 parts of 2.5 dimethyl 2.5 ditertiary butyl peroxyhexane. The composition was filled in a rubber stopper mold and press-vulcanized at 170 ° C. for 10 minutes to obtain a silicone rubber stopper (15 × 10 mmφ). The surface lubricity of the obtained silicone rubber plug was good, and when an injection needle was inserted into this rubber plug to investigate its internal lubricity, it showed extremely good slipperiness. In addition, when the center of this molded product was cut and the inside was observed with a microscope, it was observed that a part of the dimethyl silicone oil contained in the silicone powder granules had migrated into the silicone rubber. It was

Example 2 Both ends of the molecular chain were blocked with dimethylvinylsiloxy groups. 100 parts of dimethylpolysiloxane with a viscosity of 500 Stokes Stokes (vinyl group content 0.5% by weight) was blocked with trimethylsiloxy groups at both ends as a silicone oil. 20 parts of a dimethylsiloxane-methyl (3,3,3-fluoropropyl) siloxane copolymer having a viscosity of 5000 centistokes (hereinafter referred to as fluorosilicone oil) and a viscosity of 10 cm with both molecular chain ends blocked with trimethylsiloxy groups. 6 parts of Stokes' methylhydrogen polysiloxane (content of silicon atom-bonded hydrogen atoms: 1.5% by weight) was added and mixed (mixture A).

Next, 20 parts of fluorosilicone oil and 0.6 part of an isopropyl alcohol solution of chloroplatinic acid (platinum content 3% by weight) were added to 100 parts of the same dimethylpolysiloxane as above and mixed (mixture B).

The mixtures A and B were mixed in a colloid mill in the same manner as in Example 1 to obtain fluorosilicone oil-containing silicone rubber powder particles in the same manner as in Example 1.

The average diameter of the obtained silicone rubber powder granules was 15 μm. The silicone rubber powder granules were blended with the silicone rubber composition in the same manner as in Example 1, and the dispersibility and migration of fluorosilicone oil to silicone rubber were examined in the same manner as in Example 1. The same result as in Example 1 was obtained.

Example 3 30 parts of a dimethylpolysiloxane having a viscosity of 1000 centistokes (vinyl group content: 0.25% by weight) having both chain ends blocked with dimethylvinylsiloxy groups, and a viscosity having both chain ends blocked with a dimethylvinylsiloxy group Dimethylsiloxane-methylvinylsiloxane copolymer of 1000 centistokes (vinyl group content 0.5% by weight), methylhydrogenpolysiloxane of viscosity 5 centistokes with both ends of the molecular chain blocked by trimethylsiloxy groups (silicon-bonded hydrogen 1.5 parts of an atomic content of 0.8% by weight) and dimethylpolysiloxane having a viscosity of 350 centistokes blocked at both ends with trimethylsiloxy groups as silicone oil (mixture A).

Next, 30 parts of the same dimethylpolysiloxane whose both molecular chain ends were blocked with dimethylvinylsiloxy groups, 70 parts of the same dimethylsiloxane-methylvinylsiloxane copolymer as described above, and dimethylpolysiloxane of the same viscosity of 350 centistokes as above. 70 parts of siloxane and 0.6 part of an isopropyl alcohol solution of chloroplatinic acid (platinum metal content: 3% by weight) were added and mixed.

The mixture A and the mixture B were fed into a static mixer previously cooled to -10 ° C by using a pressure-feeding pump, and 1:
The mixture was mixed at a ratio of 1 (weight ratio) to obtain an aqueous dispersion of the silicone gel composition.

On the other hand, a hot water tank with a temperature of 85 ° C was prepared with a stirring blade for generating a spiral flow in the center.

Then, the silicone gel composition obtained above was continuously extruded into the warm water through a discharge nozzle. The silicone gel composition extruded from the nozzle flowed and was cut into spheres. The obtained silicone gel powder granules had an average diameter of 1 to 10 mm and contained 65% by weight of silicone oil.

Example 4 The dimethyl silicone oil-containing silicone rubber powder granules obtained in Example 1 and 100 parts of ABS resin [Toyolac Co., Ltd.] pellets were mixed in a Henschel mixer.
The mixture obtained is a single-screw vent type extruder (pelletizer).
The mixture was fed into and extruded and pelletized while being heated and mixed. The dimethylsilicone oil-containing silicone rubber powder granules were not separated from the ABS resin pellets, and pellets having a uniform shape were obtained because the extruder was difficult to mix. Further, when the dimethyl silicone oil contained in the pellets thus obtained was quantified, the amount of dimethyl silicone oil contained in each pellet was constant.

For comparison, 5 parts of the dimethyl silicone oil used in Example 1 and 100 parts of the same ABS resin pellets as above were mixed in a Henschel mixer. Then, when the obtained mixture was pelletized in the same manner as above, ABS resin pellets were not slipped into the screw and forcedly pushed into the extruder using a pushing rod, and pelletized. Was not constant, and the amount of dimethyl silicone oil contained in the pellets varied widely and was not constant.

〔The invention's effect〕

The silicone powder containing the silicone oil of the present invention is
Contains 80% by weight of silicone oil and has an average diameter of 0.1
Since it is in the range of up to 20000 μm, it has lubricity itself,
Silicone powder granules with excellent impact absorbency, which can be used as lubricants, buffers, shock absorbers, and when added to various materials such as various rubbers including silicone rubber and organic resins. Can be dispersed uniformly with good workability, and various physical properties such as internal lubricity, surface lubricity, wear resistance, impact strength, internal stress relaxation, water resistance, etc. It has a feature that it can be added.

Claims (3)

[Claims] 1. A cured silicone powder granule containing 0.5 to 80% by weight of a silicone oil and having an average particle diameter of 0.1 to 20000 μm, wherein the cured silicone is obtained by heating and curing an organopolysiloxane or an organopolysiloxane composition. A cured product obtained by the above, wherein the silicone oil is uniformly dispersed in the cured silicone powder, and a cured silicone powder containing silicone oil. 2. The cured silicone powder granules containing silicone oil according to claim 1, which is an additive for modifying rubber. 3. The cured silicone powder granules containing silicone oil according to claim 1, which is an additive for modifying an organic resin.