JP3032229B2 - Curable polyorganosiloxane-supported powder, method for producing the same, method for producing polyorganosiloxane elastic fine powder, and synthetic resin composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a powder carrying a curable polyorganosiloxane composition and a method for producing the same, and also comprises curing a curable polyorganosiloxane-supported powder. More particularly, the present invention relates to a synthetic resin composition in which microdomains of a cured polyorganosiloxane are formed.

[Prior art and its problems] Polyorganosiloxane compositions exhibiting elasticity are known as so-called silicone rubbers, and are widely used in various industrial fields. Examples of the silicone rubber include a millable silicone rubber that is processed by press molding or extrusion molding, and a liquid silicone rubber that solidifies from the fluid state or the paste state by moisture or heating in the air. , Potting objects, coating layers, adhesive layers, and the like.

However, recently, various polyorganosiloxanes characterized by other shapes have been developed.
For example, JP-A-63-77940 discloses a spherical polyorganosiloxane powder.
No. 663 discloses a silicone rubber fiber. These have not only characteristics based on the material of polyorganosiloxane but also new characteristics derived from the shape thereof, and are expected to exhibit unique functions.

That is, while the powder of silicone rubber has properties such as heat resistance and cold resistance, weather resistance, and water repellency possessed by silicone, it is stress-relaxed by blending it as an elastic powder, for example, into a synthetic resin. It can impart properties, relieve molding distortion, improve releasability, impart water repellency, and the like. Further, by adding to the paint, flexibility and impact resistance can be improved.

Conventionally, in the production of such silicone rubber powder, a method of mechanically pulverizing a cured silicone rubber has been employed, as in the case of general organic rubber fine powder. However, it is difficult to make the particle size finer by mechanical pulverization, and silicone rubber is excellent in cold resistance, and a freeze-pulverization method cannot be used.

Therefore, various studies have been made on pulverization of silicone rubber by a method other than mechanical pulverization. As one of them, there is an idea that an uncured composition is formed into fine particles and then cured to form a fine silicone rubber powder. That is, a so-called addition-type liquid silicone rubber consisting essentially of an alkenyl group-containing polyorganosiloxane, a polyorganosiloxane containing a hydrogen atom bonded to a silicon atom, and a hydrosilylation reaction catalyst, in an uncured state. There is disclosed a method of dropping and curing a heated liquid having no compatibility (Japanese Patent Application Laid-Open No. 61-223032, etc.).

However, the above-mentioned method for producing a silicone rubber fine powder, in which the fine particles are formed in an uncured state and then cured, the viscosity or curing mechanism of the polyorganosiloxane composition that can be finely divided is limited, or a complicated production apparatus or In addition, there is a problem in manufacturability because a post-process such as medium separation is required.

Next, the application of the silicone rubber powder will be described. In order to improve the characteristics of the synthetic resin, various additives are blended. Examples of additives include low molecular weight compounds such as plasticizers such as dioctyl phthalate and antioxidants such as hindered phenols.In recent years, high molecular weight compounds have been added to polymer alloys and IPs.
There are many examples of improving the characteristics by forming a polymer structure similar to N (Interpenetrating Polymer Network).

Polyorganosiloxane is one of the additives used in this manner. Linear silicone oils are sometimes used as polyorganosiloxanes, but these have low crystallization temperatures and are liable to cause macroscopic phase separation in the resin. Not very appropriate for

To solve the problem of macro phase separation, two methods have been considered. One is a method in which a polyorganosiloxane is bonded to a base polymer of a synthetic resin to form a graft or block copolymer. The other is a method in which a crosslinked polyorganosiloxane is mixed and dispersed in a synthetic resin to form microdomains.

Since the latter compounding and dispersing method can be performed at the stage of molding and processing the synthetic resin, it has an advantage that the user guide has a high degree of selection. Specifically, the cured silicone rubber is pulverized into powder and kneaded into resin,
Further, a method has been adopted in which a curable polyorganosiloxane composition is kneaded into a resin in an uncured state, and the polyorganosiloxane composition dispersed in the resin is cured.

However, the method of kneading the silicone rubber powder is
Not only is there a certain limit to the fineness of the rubber that can be crushed, it is not enough to exert the characteristics of the microstructure,
There is a problem that the interface between the silicone rubber powder and the synthetic resin is easily peeled off. In addition, the method of kneading the curable polyorganosiloxane composition into the resin in an uncured state is poor in mutual wettability between the synthetic resin and the polyorganosiloxane composition, making it difficult to uniformly disperse, and poor in workability. There were difficulties.

[Objects of the Invention] An object of the present invention is to provide a curable polyorganosiloxane-supported powder, a method for producing a curable polyorganosiloxane-supported powder, and a polyorganosiloxane elasticity, which has a wide range of applications, is simple and has excellent productivity. An object of the present invention is to provide a method for producing body fine powder.

Another object of the present invention is to provide a synthetic resin composition in which a curable polyorganosiloxane is uniformly and microscopically dispersed.

[Constitution of the Invention] As a result of various studies, the present inventors have produced an intermediate-stage powder in which an uncured polyorganosiloxane composition is supported on the powder surface, and then cured itself. By doing so, it was found that polyorganosiloxane elastomer fine powder was obtained. It has also been found that a new intermediate stage powder, an uncured polyorganosiloxane-supported powder, is useful. That is, it was found that if the powder at the intermediate stage was mixed with a synthetic resin and cured, a synthetic resin composition having a crosslinked polyorganosiloxane having a microdomain structure was obtained, and the present invention was achieved.

That is, the curable polyorganosiloxane-supported powder of the first invention is obtained by mixing an uncured curable polyorganosiloxane composition on the surface of a powder having an average particle size of 1 μm or less without using a non-aqueous solvent. It is characterized by being carried.

The method for producing a curable polyorganosiloxane-supported powder according to the second invention comprises mixing the curable polyorganosiloxane composition in an uncured state with a powder having an average particle size of 1 μm or less without using a non-aqueous solvent. The method is characterized in that fine particles having a polyorganosiloxane composition supported on the surface of the powder are generated.

According to a third aspect of the present invention, there is provided a method for producing a polyorganosiloxane elastic fine powder, comprising mixing an uncured polyorganosiloxane composition with a powder having an average particle size of 1 μm or less in an uncured state. The method is characterized in that the organosiloxane composition is mixed and supported on the surface of the powder without using a non-aqueous solvent, and then cured under the curing conditions of the polyorganosiloxane to generate elastic fine particles.

The synthetic resin composition of the fourth invention is characterized in that the curable polyorganosiloxane composition in an uncured state contains a powder supported on the surface of a powder having an average particle diameter of 1 μm or less without using a non-aqueous solvent. And

 Hereinafter, the present invention will be described in detail.

An element constituting the first invention comprises a curable polyorganosiloxane composition and a powder supporting the same.

As the curable polyorganosiloxane composition used in the present invention (first to fourth inventions), those having various curing mechanisms known so far can be used. For example, an alkenyl group-containing polyorganosiloxane, a polyorganosiloxane containing a hydrogen atom bonded to a silicon atom, and those cured by an addition-type reaction consisting essentially of a hydrosilylation reaction catalyst, a silanol-containing polyorganosiloxane, Those cured by a condensation-type reaction consisting essentially of an organosilicon compound having a hydrolyzable group and a condensation catalyst, those cured by a radical-type reaction consisting essentially of an alkenyl group-containing polyorganosiloxane and a peroxide And so on. The degree of polymerization of the base polymer constituting them can be used from those exhibiting fluidity in a liquid state to those exhibiting semi-plasticity. In addition, properties after curing, from resin-like to rubber-like,
Further, even those that become gel-like can be used.

Depending on the type of the above-mentioned curable polyorganosiloxane composition, process conditions for supporting the curable polyorganosiloxane composition on the powder surface and use conditions of the surface-supported powder are affected. From the viewpoint that the degree of freedom of these conditions is the largest, those cured by an addition-type reaction are preferable.

In the present invention, the powder supporting the curable polyorganosiloxane composition is not particularly limited, but inorganic powder such as silica, calcium carbonate, diatomaceous earth, kaolin, and talc, nylon powder, and Teflon powder. And organic powders such as polyorganosilsesquioxane powder. Among them, silica powder and polyorganosilsesquioxane powder, which contain few impurities and have a chemical structure similar to silicone, are more preferable. The average particle size of the powder is 1.0μ
m or less.

The method for producing a curable polyorganosiloxane-supported powder according to the second invention is characterized in that the curable polyorganosiloxane composition is mixed with the powder in an uncured state, and the polyorganosiloxane composition is powdered. This is a method of supporting the body surface without using a non-aqueous solvent. The non-aqueous solvent refers to a solvent such as benzene, trichloroethylene, and trichloroethane. The mixing ratio of the curable polyorganosiloxane composition and the powder is not particularly determined because it depends on the properties of the powder, but the crosslinked poly that is finally formed after the uncured polyorganosiloxane-supported powder is used is used. It is preferable to mix the polyorganosiloxane composition having the same weight or more with respect to the unsupported powder in consideration of the characteristics of the organosiloxane. However, when the polyorganosiloxane composition is mixed in an amount not less than the oil absorption of the unsupported powder, a continuous phase of the composition is often formed and does not become a powder. Mixing is achieved by mixing both materials in a suitable mixer. When the curable polyorganosiloxane composition has a low viscosity, a device such as a double-arm kneader or an attritor can be used.However, when the viscosity is extremely high, a device such as a kneader or a Henschel mixer is used. It is effective when used. The curable polyorganosiloxane-supported powder thus obtained can be subjected to post-treatment such as classification.

Next, the production of the fine polyorganosiloxane elastic powder of the third invention is obtained by curing the uncured polyorganosiloxane-supported powder to be an elastic material obtained by the method of the second invention by an appropriate method. The curing method and the curing conditions may be selected appropriately according to the curing mechanism of the polyorganosiloxane composition.However, addition-type reactions and radical-type reactions are cured by heating, and condensation-type reactions are cured by moisture. What is necessary is just to hold | maintain in the heating furnace and humidification tank which create such an environment. Depending on the composition of the polyorganosiloxane composition, the composition can be cured by leaving it in the air. After curing, a post-treatment such as classification may be performed. The method for producing an elastic fine powder according to the third aspect of the invention is much simpler than the above-mentioned conventional method, and is excellent in productivity.

In addition, the curable polyorganosiloxane-supported powder obtained by the first and second invention methods has a higher synthetic resin than a case where the original polyorganosiloxane composition is used without being supported on the powder. To obtain a synthetic resin composition which can be easily dispersed in microscopic uniform dispersion. In this compounding step, the synthetic resin and the supported powder can be mixed with a batch mixer, or the mixer, a lightweight device, and a feeder can be placed and mixed before the resin is injected for continuous molding of the resin. it can.

As described above, the synthetic resin composition of the fourth invention containing the curable polyorganosiloxane-supported powder can be obtained by curing the uncured polyorganosiloxane composition by an appropriate method. Organosiloxane microdomains are formed.

[Effects of the Invention] The method for producing a polyorganosiloxane elastic fine powder of the present invention has a wide application range of a polyorganosiloxane composition that can be pulverized, and has a simple production process and a simple apparatus, and is excellent in productivity. It is. As a result, not only can the variety of properties of the polyorganosiloxane elastic fine powder be expanded, but also the mass production of the polyorganosiloxane elastic fine powder can be economically advantageous, and the composite having a new function can be obtained. It greatly contributes to the development of the body. In addition, when the uncured curable polyorganosiloxane-supported powder is blended with a synthetic resin or the like, a microstructure of a crosslinked polyorganosiloxane sufficient to exhibit excellent properties can be formed, and blended with the synthetic resin. It is easily and uniformly dispersed. This forms the microdomains of the crosslinked polyorganosiloxane,
It is possible to improve the properties of the synthetic resin and to improve the efficiency and simplification of production.

EXAMPLES Next, examples of the present invention will be described, but the present invention is not limited by the following examples. The “viscosity” described below is a value at 25 ° C., and “parts” means parts by weight.

Example 1 100 parts of polydimethylsiloxane capped at both ends with a vinyl group having a viscosity of 800 cP, 3 parts of methylhydrogenpolysiloxane having a viscosity of 30 cP and an active hydrogen content of 0.86%, and 0.03 part of octanol chloroplatinate (4% platinum content) , 3-methyl-1
-0.03 parts of butyn-3-ol are mixed until uniform,
Thus, a polyorganosiloxane composition-1 was obtained. 100 parts of wet silica powder having an average particle size of 0.015 μm was added to 150 parts of the polyorganosiloxane composition-1 and mixed with a double-arm kneader under cooling to obtain a polyorganosiloxane-supported powder-1.
I got The average particle size of this fine powder is 4 μm and the particle size is 0.2
It was distributed in the range of 8080 μm.

Examples 2 to 6, Comparative Example 1 100 parts of the unsupported powder shown in Table 1 and 150 parts of the polyorganosiloxane composition-1 were mixed by the method shown in Example 1 to obtain a polyorganosiloxane-supported powder. Body-2 to 6 were obtained. When the unsupported powder of Comparative Example 1 was used, the composition became a continuous phase after mixing with the double-arm kneader, and the polyorganosiloxane-supported powder was not obtained.

Example 7 100 parts of α, ω-polydimethylsiloxane diol having a viscosity of 3000 cP, 3 parts of α, ω-polydimethylsiloxane diol having a viscosity of 15 cP, 2 parts of ethyl silicate, and 0.35 part of dibutyltin dilaurate are made uniform by blocking out moisture. To obtain a polyorganosiloxane composition-2. Polyorganosiloxane composition-2 Average particle size 0.012μ in 180 parts
Then, 100 parts of fumed silica powder was added and mixed with a double-arm kneader under the exclusion of moisture to obtain polyorganosiloxane-supported powder-7. The average particle size of this fine powder was 5 μm.

Example 8 100 parts of methylvinylpolysiloxane raw rubber having a viscosity of 1,500,000 cP and a vinyl group content of 0.4 mol% was mixed with 0.2 parts of 2,4-dichlorobenzoyl peroxide by a roll until uniform,
Thus, a polyorganosiloxane composition-3 was obtained. To 150 parts of the polyorganosiloxane composition-3, 100 parts of wet silica powder having an average particle size of 0.015 was added and mixed with a kneader under cooling to obtain a polyorganosiloxane-supported powder-8.
The average particle size of this fine powder was 30 μm.

Example 9 100 parts of polydimethylsiloxane capped at one end with a vinyl group having a viscosity of 700 cP, 0.8 parts of methylhydrogenpolysiloxane having a viscosity of 30 cP and having an active hydrogen content of 0.86%, and octanol complex chloroplatinate (4% of platinum content) 0.01 And 0.2 part of triallyl isocyanurate were mixed until uniform, to obtain a polyorganosiloxane composition-4. 100 parts of polymethylsilsesquioxane powder having an average particle size of 0.01 μm was added to 150 parts of the polyorganosiloxane composition-4 and mixed with a double-arm kneader under cooling to obtain a polyorganosiloxane-supported powder-9. Obtained. The average particle size of this fine powder is 4 μm
The particle size was distributed in the range of 0.2 to 70 μm.

Example 10 The polyorganosiloxane-supported powder-1 of Example 1 was allowed to stand at 130 ° C. for 1 hour in a drier to obtain a polyorganosiloxane elastic fine powder-10. The average particle size of this fine powder was 4 μm, and the particle size was distributed in the range of 0.2 to 80 μm. By the way, this fine powder was added to toluene at room temperature for 48 hours.
Since the polyorganosiloxane was not substantially extracted even after immersion for a time, it can be said that this fine powder is a cured product.

Examples 11 to 15 and Comparative Example 2 Polyorganosiloxane-supported powder-2 of Examples 2 to 6
To 6 were obtained in the same manner as in Example 10 to obtain polyorganosiloxane elastic fine particles-11 to 15 shown in Table 2. As described above, in Comparative Example 1, a polyorganosiloxane-supported powder was not obtained, and a continuous phase was formed. In Comparative Example 2, however, the continuous phase was treated in the same manner as in Example 10. However, fine polyorganosiloxane elastic powders as in Examples 11 to 15 were not obtained.

Example 16 The polyorganosiloxane-supported powder-7 obtained in Example 7 was allowed to stand in an environment of 25 ° C. and 60% RH for 48 hours to obtain a polyorganosiloxane elastic fine powder-16.
The average particle size of this fine powder was 5 μm. By the way, even if this fine powder was immersed in toluene at room temperature for 48 hours, the polyorganosiloxane was not substantially extracted.

Example 17 The polyorganosiloxane-supported powder-8 obtained in Example 8 was allowed to stand in a hot-air dryer at 150 ° C. for 1 hour to obtain a polyorganosiloxane elastic fine powder-17.
The average particle size of this fine powder was 30 μm. By the way, even if this fine powder was immersed in toluene at room temperature for 48 hours, the polyorganosiloxane was not substantially extracted.

Example 18 The polyorganosiloxane-supported powder-9 obtained in Example 9 was allowed to stand in a hot-air dryer at 150 ° C. for 1 hour to obtain a polyorganosiloxane elastic fine powder-18.
The average particle size of this fine powder was 4 μm, and the particle size was distributed in the range of 0.2 to 70 μm. Incidentally, even if this fine powder was immersed in toluene at room temperature for 48 hours, polyorganosiloxane was not extracted more than expected. The supported polyorganosiloxane composition-4 gives a gel having a penetration of 80 when cured.

Example 19 100 parts of a novolak type phenol resin was heated to 150 ° C. and melted, and while stirring, 151 parts of a polyorganosiloxane-supported powder was added. The polyorganosiloxane-carrying powder-1 was promptly and uniformly mixed.
After stirring for 1 hour as it was, it was cooled and taken out. When this was cut and its surface was observed with a scanning electron microscope, it was found that the silicone microdomains were formed cleanly and uniformly.

Comparative Example 3 A polyorganosiloxane composition was prepared in the same manner as in Example 19, except that the polyorganosiloxane-supported powder-1 (151 parts) was used.
The same operation as in Example 19 was performed using 130 parts (the amount of the polyorganosiloxane composition was the same as in Example 19). Even though the polyorganosiloxane composition-1 was added little by little, it did not easily penetrate, and it took more than three times as long as in Example 19 until it became uniform. As a result of cutting the product and observing the surface with a scanning electron microscope, the microdomains of the silicone were irregular and non-homogeneous as compared with Example 19.

Example 20 100 parts of a polypropylene resin pellet was mixed with 25 parts of a polyorganosiloxane-supported powder, and the mixture was injected into a mold at a mold temperature of 150 ° C. using a screw extruder to obtain a molded product. When the molded body was cut and its surface was observed with a scanning electron microscope, it was found that the silicone microdomains were formed cleanly and uniformly.

Continuation of front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08L 83/04 C08K 3/00

Claims (4)

(57) [Claims] An uncured curable polyorganosiloxane composition is supported on a surface of powder having an average particle diameter of 1 μm or less by mixing without using a non-aqueous solvent. Polyorganosiloxane-supported powder. 2. A curable polyorganosiloxane composition comprising:
Mixing the powder having an average particle size of 1 μm or less in an uncured state without using a non-aqueous solvent to form fine particles having the polyorganosiloxane composition supported on the surface of the powder. A method for producing a curable polyorganosiloxane-supported powder. 3. A polyorganosiloxane composition, which is cured to give an elastic body, is mixed with a powder having an average particle size of 1 μm or less in an uncured state without using a non-aqueous solvent. A polyorganosiloxane fine powder is produced by causing the polyorganosiloxane to be supported on the surface of the powder and then curing under the curing conditions of the polyorganosiloxane to produce elastic fine particles. 4. A synthetic resin composition characterized in that the curable polyorganosiloxane composition in an uncured state contains a powder supported on the surface of a powder having an average particle diameter of 1 μm or less without using a non-aqueous solvent. Stuff.