JPS63309565A - Aqueous dispersion of silicone rubber particle - Google Patents

Abstract

PURPOSE:To obtain the title aqueous dispersion excellent in storage stability and useful as a mold release or a lubricant, by mixing water with silicone rubber particles of a specified average particle diameter and a surfactant. CONSTITUTION:Silicone rubber particles (B) of an average particle diameter of 0.1-1,000mum, preferably, 0.5-20mum are obtained by dispersing a liquid addition-curing silicone rubber composition (a) comprising an organopolysiloxane (i) having at least two alkenyl groups in the molecule, an organohydrogenpolysiloxane (ii) having at least two Si-bonded atoms in the molecule and a platinum compound catalyst (iii) in water (c) as fine particles in the presence of, optionally, a surfactant (b) and heating the formed dispersion. 100pts.wt. water (A) is mixed with 1-35pts.wt. component B and 0.05-10pts.wt. surfactant (C).

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an aqueous dispersion of silicone rubber granules, and more specifically, when this is applied to the surface of various substrates, the surface of the substrate has a The present invention relates to an aqueous dispersion of silicone rubber granules having a 5F characteristic that provides excellent lubricity and mold release properties.

[Prior Art] Aqueous dispersions containing silicone oil as a main component are known and widely used as lubricants or mold release agents.

[Problems to be Solved by the Invention] However, when an aqueous dispersion containing silicone rubber oil as a main component is applied to the surface of various base materials, the surface of the base material becomes sticky, dirt, and flakes. There is a problem that it adsorbs and becomes dirty, and there is also a problem that it has poor lubricity or mold release properties depending on the application.

The present invention aims to solve such problems, and has the characteristic that when applied to the surface of various base materials, it can impart excellent lubricity and mold releasability to the surface of the base material. An object of the present invention is to provide an aqueous dispersion of silicone rubber granules having the following properties.

E Means for solving the problem and its effect J The present invention includes (^) 100 parts by weight of water, (I
t) 1 to 35 parts by weight of silicone rubber granules having an average particle diameter of 0.1 to 1000 μI, and (C) a surfactant 0.05 to 10 parts by weight.

To explain this, the component (^) used in the present invention, water, is a medium for uniformly dispersing the silicone rubber particles, and is not particularly limited as long as it is water.

The silicone rubber granules used in the present invention as component (1) are required to have an average particle size of 0.1 to 1000 μm, preferably 0.5 to 20 μm. This is because when the average particle diameter is less than 0.1 μm, stickiness occurs, and when it exceeds 1000 μm, storage stability as an aqueous dispersion is lost. The silicone rubber used to form such silicone rubber granules is not particularly limited, and examples thereof include diorganopolysiloxane having hydroxyl groups at both ends of the molecular chain and organohydrosiloxane having at least three silicon-bonded hydrogen atoms in one molecule. A condensation reaction-curing silicone rubber obtained by dehydrogenating diene bolysiloxane in the presence of a condensation reaction catalyst, an organopolysiloxane having at least two alkenyl groups in one molecule, and at least two alkenyl groups in one molecule. Addition reaction-curing silicone rubber obtained by addition-reacting an orlf/hydrodiene polysiloxane having silicon-bonded hydrogen atoms in the presence of a platinum catalyst, having vinyl groups at both ends of the molecular chain and/or in the side chain. Examples include radical reaction-curable silicone rubbers obtained by radically reacting diorganopolysiloxanes in the presence of organic peroxides, but in the present invention, the former two are preferred from the viewpoint of ease of production. The silicone rubber granules of component (13) can be obtained by a number of methods, but it is sufficient if an aqueous dispersion of silicone rubber granules with good storage stability can be finally obtained.
The manufacturing method is not particularly limited. Specific examples of the method for producing the silicone rubber granules of component (B) include the following method.

(1) Organopolysiloxane containing at least two alkenyl groups, such as vinyl groups, in one molecule and organopolysiloxane containing at least two silicon-bonded hydrogen atoms in one molecule. A liquid addition reaction-curing silicone rubber composition consisting of siloxane and a platinum compound catalyst is placed in water itself or water containing a surfactant, and the water itself or water containing a surfactant is stirred to cure the silicone rubber composition. The rubber composition is dispersed in the form of fine particles to leave an aqueous dispersion of the liquid silicone rubber composition, and then the ice-water dispersion is heated to cure the liquid silicone rubber composition, or the dispersion is heated to a temperature of 25°C.
It is obtained by dispersing the liquid silicone rubber composition in water heated above and curing the liquid silicone rubber composition into particles.

(2) In addition, at least two hydroxyl groups are added at both ends of the molecular chain.
A liquid condensation reaction-curing silicone rubber composition consisting of an organopolysiloxane containing hydrogen atoms, an orhydrononine polysiloxane containing at least three silicon-bonded hydrogen atoms per molecule, and an organotin peroxide catalyst. By placing the product in water itself or water containing a surfactant and stirring the water itself or water containing a surfactant, the silicone rubber composition is dispersed into fine particles and the liquid silicone rubber composition is dissolved in water. A dispersion is prepared, and then the ascites dispersion is left as is for a long period of time, or heated, or the aqueous dispersion is dispersed in water heated to a temperature of 25° C. or higher, and the liquid silicone rubber composition is granulated. Obtained by curing. The blending amount of the (El) component is in the range of 1 to 35 parts by weight, preferably in the range of 5 to 25 parts by weight, per 100 parts by weight of the (^) component. This is because if the amount is less than 1 part by weight, the amount of component (B) will be too small, and when applied to the surface of various base materials, it will not be possible to impart lubricity and mold release properties to the surface of the base material. This is because if the amount exceeds 35 parts by weight, the storage stability of the silicone rubber granules as an aqueous dispersion decreases.

The surfactant (C) used in the present invention has the function of uniformly dispersing the silicone rubber particles (B) in water and improving the storage stability of the aqueous dispersion of the present invention. do. Component (C) is a conventionally known surfactant or emulsifier useful for forming a silicone oil emulsion, and is not particularly limited. Such surfactants include the following nonionic surfactants, anionic surfactants, and cationic surfactants.
Among these, nonionic surfactants are preferably used.

Examples of nonionic surfactants include polyoxyalkylene alkyl ether, polyoxyalkylene alkyl phenol, polyoxyalkylene alkyl ester, polyoxyfulkylene sorbitan ester, polyethylene glycol, polypropylene glycol, and ethylene oxide adduct of diethylene glycol trimethyl 7-nanol. is exemplified.

Examples of anionic surfactants include flukylbenzenesulfonic acids such as hexylbenzenesulfonic acid, octylbenzenesulfonic acid, decylbenzenesulfonic acid, dodecylbenzenesulfonic acid, cetylbenzenesulfonic acid, myristylbenzenesulfonic acid, cll, (C112 )scH20(C211.0)2s
O, IfClh(C11□>, C11.0(C211.
0), SO, 11CI+, (C112>l, C112
0(C2H.0)2SO,HCH3(C112)8C1
1□1. l+. Examples include sulfuric acid esters of polyoxyethylene monoalkyl ethers such as 0(C211.0)2SO311 and flukylnaphthylsulfonic acid.

Examples of cationic surfactants include octyltrimethylammonium hydroxide, dodecyltrimethylammonium hydroxide, hexadecyltrimethylammonium hydroxide, octyltrimethylbenzylammonium hydroxide, decyldimethylbennolammonium hydroxide, nooctadecyldimethylammonium hydroxide, Examples include ffi4a7 ammonium hydroxide and salts thereof such as beef tallow trimethylammonium hydroxide and coconut oil trimethylammonium hydroxide.

Note that some surfactants used in the present invention may be unsuitable depending on the type of silicone rubber and the manufacturing method of silicone rubber granules.
1o) It is necessary to appropriately select and use a surfactant suitable for the method for producing silicone rubber granules. For example, as described in (1) above, an addition reaction-curable silicone rubber composition that can be cured with a platinum catalyst is discharged into water containing a surfactant and emulsified, and then the silicone rubber composition is cured to form silicone rubber particles. In order to obtain the above-mentioned (2), surfactants containing atoms that deactivate the platinum catalyst, such as sulfur atoms and phosphorus atoms, are undesirable because they inhibit the curing of the addition reaction-curable silicone rubber composition. A condensation reaction-curing silicone rubber composition, which is cured by the dehydrogenation reaction of an organo-gamma-novolisiloxane containing a vinyl group and an organohydrothene polysiloxane containing a hydrogen atom bonded to a silicon atom, is added to water containing a surfactant. When the silicone rubber composition is discharged and emulsified and then cured to obtain silicone rubber granules, anionic emulsifiers are not preferred because they impair the stability of the organohydrothene polysiloxane.

Furthermore, in the present invention, the surfactant is 111 or 2
You may use more than one species in combination. The blending amount of component (C) is 0.05 to 1 per 100 parts by weight of component (^)
It is within the range of 0 parts by weight, preferably within the range of 0.5 to 5 parts by weight.

If it is less than 0.05 parts by weight, the storage stability of the aqueous dispersion of the present invention will decrease and the silicone rubber particles will separate from water, and if it exceeds 10 parts by weight, the amount of surfactant will be too large. This is because it becomes impossible to impart excellent lubricity and mold release properties to the surfaces of various base materials.

The present invention can be easily obtained by uniformly mixing the above components (8) to (C). Alternatively, when the above component (B) is produced in water containing a surfactant as in (1) or (2) above, the resulting aqueous dispersion of silicone rubber particles itself can be amount, amount of silicone rubber granules, amount of emulsifier.

That is, it can also be obtained by adding a predetermined amount of water and/or a surfactant to the aqueous dispersion of silicone rubber particles obtained in (1), and uniformly mixing and stabilizing it. Furthermore, in the present invention, during the production of the above (1), the amount of components (^) to (C) is reduced to 3!1! (
It can also be obtained by blending predetermined amounts of each of the components ^) to (C). In addition, when the above component (B) is left in water that does not contain a surfactant, that is, in a water bottle, a predetermined amount of the component (C) is added to the aqueous dispersion of the silicone rubber granules obtained. It can be easily obtained by adding a predetermined amount of component (8) to the emulsion to form an emulsion and then stabilizing it by adding a predetermined amount of component (8).

The aqueous dispersion of the present invention has excellent storage stability, and when applied to various substrates, it imparts excellent lubricity and mold releasability to the surface of the substrate. Therefore, it is suitably used as a lubricant or mold release agent.

[Example] Next, the present invention will be explained with reference to an example. "Example Middle" indicates parts by weight.

Example 1 Trimethylpolysiloxane with a viscosity of 80 centivoids having hydroxyl groups at both ends of the molecular chain (hydroxyl group content: 11.5 cm)
12 parts of 7-methylhydrodiene polysiloxane (content of silicon-bonded hydrogen atoms: 1.5% by weight) having a viscosity of 10 centivoids and having trimethylsiloxy groups at both ends of the molecular chain were added to 100 parts (weight 1%). (Mixture A).

Next, 2 parts of butyltin octoate was added to 100 parts of the same trimethylpolysiloxane as above and mixed to obtain a mixture similar to the above (mixture B).

Mixture A and Mixture B were placed in separate storage tanks, and these tanks were cooled to -10°C. Next, 100 parts of this mixture A and 100 parts of mixture B were fed into a static mixer [vFa, manufactured by Isoka Kogyo Co., Ltd., with 10 elements], mixed uniformly and sent to a colloid mill, and at the same time, 1000 parts of water and a surfactant were added. (2.5 parts of ethylene oxide adduct of trinotylnonanol, manufactured by Union Carbide Corporation, nonionic surfactant, Tajitol TMN-6) were fed and mixed under the conditions of 1400 rotations/rotation gap 0.1 + nio, and silicone An aqueous dispersion of rubber granules is prepared by 11'P. The silicone rubber particles in the aqueous dispersion were taken out and their particle size was measured, and the average particle size was 5 μm. This aqueous silicone rubber dispersion was extruded and filled into a bath for electric wires.

Next, an electric wire with a diameter of 5III# coated with hard vinyl chloride 11 fat was immersed and passed through the bath at a rate of 301/min, and then passed through a drying oven to remove moisture adhering to the surface of the electric wire. The surface of the obtained electric wire has non-blocking properties,
The slipperiness was good.

Further, when an electron micrograph was taken of this '/r1-ray surface and the surface condition was observed, it was found that silicone rubber particles having an average particle diameter of 5 μI were uniformly adhered and coated. The extrusion conditions for the electric wire coated with the hard vinyl chloride resin were as follows.

Extruder screw type die diameter 5III 111 temperature 20
0°C Core wire diameter 5+u+ Bath temperature 25°C Example 2 Polysiloxane with a viscosity of 500 centivoids (fA) with both ends of the molecular chain sealed with dimethylvinylsiloxy groups (
Methylhydrodiene polysiloxane (contains 10.5% by weight of vinyl groups) and has a viscosity of 10 centivoids, in which both ends of the molecular chain are H-chained with trimethylsiloxy groups (content of silicon-bonded hydrogen atoms: 1.5% by weight) 6 (Mixture A).

Next, an isopropyl alcohol solution of chloroplatinic acid (platinum-containing J13
(Mixture B) Mixture A and Mixture B were mixed in a colloid mill in the same manner as in Example 1 to obtain an aqueous dispersion of a liquid silicone rubber composition. When the obtained aqueous dispersion was left as it was for 24 hours to cure the liquid silicone rubber composition, an aqueous dispersion containing silicone rubber particles with an average particle size of 7 μl was obtained. Next, this aqueous dispersion was filled in the same bath as in Example 1, and then an electric wire coated with heat-curing silicone rubber and having a diameter of 8 ff 1 m was immersed and passed through the bath at a wire speed of 30 ra/min. When the obtained wire was dried and its surface condition was examined, it was found that there was no blocking property at all on the surface, and the marking ink was lower than that of the wire surface coated with talc, which is conventionally used to prevent blocking. Adhesion was good.

Example 3 Water dispersion of silicone rubber granules obtained in Example 1! 1
00 parts, 100 parts of water and 0.0 parts of the surfactant used in Example 1.
25 parts were added and mixed.

After spraying the obtained mixture onto both walls of a metal conveyor belt for packaging and transportation, a package consisting of a 10 kg carton case was pushed out, and it moved easily without stopping midway, with an extremely slippery effect. It was found to be good.

Example 4 Aqueous dispersion 1 of silicone rubber granules obtained in Example 2
00 parts, 100 parts of water and 0.0 parts of the surfactant used in Example 2.
25 parts were added and mixed.

After spraying the obtained mixture onto the grooves or sills of sliding doors in Japanese-style buildings, the number of times the sliding door (sliding door) was moved was examined until the sliding resistance value increased. It was more than 200 times.

For comparison, trimethylpolysiloxane (tone silicone) was used instead of the aqueous dispersion of the silicone rubber granules.
When the number of times the sliding door was moved was examined in the same manner as above except that 5H200/100 centistokes manufactured by Co., Ltd. was used, the sliding resistance value increased at the 105th time the sliding door was moved.

Example 5 A press frame mold (150 x 250 x 2 m) was sandwiched between two chrome-plated metal plates, and the aqueous dispersion of the silicone rubber granules obtained in Example 1 was sprayed onto the metal plates. Spray applied and dried for 20 minutes at room temperature. Next, a liquid silicone rubber composition [5E6706 manufactured by Tone Silicone Co., Ltd.] was injected into the mold, and the mixture was heated to 150
It was cured by heating at ℃ for 5 minutes. When the obtained molded article was then taken out from the mold, the releasability from the mold was extremely good, and the surface of the molded article was glossy.

For comparison, a molded product was obtained in the same manner as above except that the aqueous dispersion of silicone rubber granules was not used.The molded product could not be easily released from the mold, and its surface was glossy. There was no.

[Effects of the Invention J] The present invention is an aqueous dispersion of silicone rubber granules consisting of (^) a predetermined amount of water, (El) a predetermined amount of silicone rubber granules, and (C) a predetermined amount of surfactant, so that it has good storage stability. It has the characteristic that when it is applied to various substrates, it imparts excellent lubricity and excellent mold releasability to the substrates.

Claims (1)

[Scope of Claims] 1 (A) 100 parts by weight of water, (B) 1 to 35 parts by weight of silicone rubber granules with an average particle size of 0.1 to 1000 μm, and (C) 0.05 to 10 parts by weight of a surfactant. An aqueous dispersion of silicone rubber granules consisting of parts. 2 Claim 1 characterized in that it is a lubricant.
An aqueous dispersion of silicone rubber granules as described in . 3 Claim 1 characterized in that it is a mold release agent
Silicone rubber granules as described in .