JPH0681809B2 - Thermoplastic resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel thermoplastic resin composition, which has a good moldability and is capable of obtaining a molded article having excellent impact resistance and abrasion resistance. It relates to a plastic resin composition.

[Conventional technology and its problems]

As a method of improving the impact resistance of various thermoplastic resins, a method of compounding a synthetic rubber such as butadiene rubber, butadiene-styrene rubber, butadiene-acrylonitrile rubber, butadiene as a polymerizable monomer, acrylonitrile or the like is copolymerized with a resin monomer. There are known methods such as a method of using both methods, and a method of using both methods in combination.

Among these methods, the method of blending a synthetic rubber with a thermoplastic resin is relatively easy, and is therefore widely used with a polystyrene resin or the like. However, simply kneading the thermoplastic resin and the synthetic rubber is considered to be because the synthetic rubber to be blended is often in the form of lumps and therefore the dispersibility as fine particles is poor, but the moldability of the resin composition In order to obtain a uniform resin composition, for example, synthetic rubber was dissolved in a polymerizable monomer, because deterioration, surface gloss of the obtained resin molded product, decrease in tensile strength, and generation of interface cracks are likely to occur. In this state, it is necessary to polymerize the monomer or to knead and blend the synthetic rubber with the thermoplastic resin under high shearing force. For example, as a method of blending and dispersing the organopolysiloxane rubber in the thermoplastic resin, as described above, a method of dissolving the vinyl group-containing organopolysiloxane rubber in a polymerizable vinyl monomer and polymerizing it (SPE Journal, Vol. 29, 58). Page (1973)), and a method of kneading and blending massive organopolysiloxane rubber under high shearing force (Japanese Patent Publication No. 52-36898). These polymerization methods and kneading methods are unsuitable as general methods because the steps are complicated and a special manufacturing apparatus is required.

Further, in order to improve the wear resistance of the thermoplastic resin,
Conventionally, various mineral oils and synthetic oils have been added and blended as lubricating oils, and they are known as oil-containing plastics. However, when these lubricating oils are added, the molten resin and the inner wall (barrel) of the molding machine are melted during the melt molding.
Lubricating oil bleeds out at the interface with the screw and screw, resulting in excessive lubrication and extremely difficult molding.
In order to add a lubricating oil sufficient to give a sufficient effect of improving wear resistance, that is, to add 1% by weight or more, it is necessary to use a special molding machine such as a twin-screw molding machine or increase the cost. It was necessary to use master pellets.

As a method for improving this inconvenience, various measures have been taken such as blending ultra-high molecular weight polyethylene with various lubricating oils such as silicone oil in advance (Japanese Patent Publication No. 47-2).
9374). However, this method is not only complicated in the process, but also has a problem that the heat resistance of the resulting thermoplastic resin composition is lowered because polyethylene is added as a result.

Further, JP-A-64-81856 discloses a silicone powder granule containing silicone oil.

This silicone powder granules is made by mixing reactive silicone oil, non-reactive silicone oil with a viscosity of 100-10,000 cSt (eg dimethyl silicone oil) and reaction catalyst, and making a uniform aqueous dispersion with a colloid mill. It is obtained by heating and reacting the aqueous dispersion with a spray dryer or the like, and is a spherical powder or granular material.

In this spherical silicone powder granule, when it is surely compounded with rubber or plastic, the impact resistance is improved,
Improvement of lubricity is expected.

However, in this prior art silicone powder granule, since the process is complicated and a limited special device is required, the production cost is high, and in order to obtain a stable water dispersion system, a surfactant is used. Is often economically disadvantageous, and when the obtained powdery or granular material is compounded with rubber or plastic, a surfactant is also added, and the rubber or rubber finally obtained is The drawback is that the heat resistance of the plastic molding is reduced.

Therefore, the object of the present invention is a thermoplastic resin composition that does not require complicated steps or special equipment, has good moldability, and also has excellent impact resistance, abrasion resistance and the like. To provide.

Another object of the present invention is to provide a thermoplastic resin composition which is excellent in economic efficiency and does not have a risk of lowering the heat resistance of the molded body.

[Means for Solving the Problems]

The present inventors have found that a thermoplastic resin composition to which a silicone powder produced under a specific condition of a thermoplastic resin is added and blended can solve the above problems.

That is, this thermoplastic resin composition has a form in which the fine particles of the silicone powder are uniformly dispersed, and exhibits excellent impact resistance or abrasion resistance.

That is, in the present invention, 100 parts by weight of a thermoplastic resin, an organohydridiene polysiloxane of the following (A) and an organopolysiloxane of the following (B) are optionally added in the presence of a silicone oil of the following (C). In the above, a thermoplastic resin composition comprising: 1 to 50 parts by weight of an amorphous silicone powder obtained by crushing the resulting polymerization product by addition polymerization under stirring and crushing under shearing force is provided. To do.

(A) An organohydrogenpolysiloxane containing an average of 1.5 or more hydrogen atoms bonded to silicon atoms in one molecule.

(B) Organopolysiloxane containing an average of 1.5 or more aliphatic unsaturated groups bonded to silicon atoms in one molecule.

(C) Silicone oil whose viscosity at 25 ° C is 100 cSt or less:
1 to 200 parts by weight based on 100 parts by weight of the total amount of the organohydrogenpolysiloxane (A) and the organopolysiloxane (B).

Accordingly, the silicone powder used in the composition of the present invention is a polymer powder partially having a three-dimensional crosslinked structure obtained by addition polymerization of the reactive organopolysiloxanes (A) and (B). The silicone oil (C) is included in the inside of the polymer powder.

In the following, first, the silicone powder, which is one component of the composition of the present invention, will be described.

As the organohydrogenpolysiloxane (A) used in the production of silicone powder, HSiO _1.5 units, R
SiO _1.5 unit, RH SiO unit, R ₂ SiO unit, R ₂ HSiO _0.5 unit, R
₃ SiO _0.5 unit [wherein R is a substituted or unsubstituted monovalent hydrocarbon group excluding an aliphatic unsaturated group, for example, an alkyl group such as methyl, ethyl, propyl or butyl; an aryl such as phenyl or tolyl] A group; a monovalent hydrocarbon group such as a cycloalkyl group such as cyclohexyl, and one or more hydrogen atoms of these monovalent hydrocarbon groups substituted by a halogen atom such as chlorine, bromine or fluorine, or a cyano group Substituted hydrocarbon groups such as γ-trifluoropropyl group, chloromethyl group and the like] and the like can be mentioned. The organohydrogenpolysiloxane (A) may be linear, branched, or cyclic, but linear is more preferable in order to smoothly carry out the addition polymerization reaction.

In addition, this organohydrogenpolysiloxane is
An average of 1.5 or more, and preferably 2 to 5 hydrogen atoms bonded to silicon atoms (Si-H bond) is contained in one molecule.

The ratio of the hydrogen atom bonded to the silicon atom in the molecule is usually 0.5 to 50 mol%, preferably 1 to 20 mol% relative to the total of the hydrogen atom bonded to the silicon atom and the organic group.

As the organic group contained in the organohydrogenpolysiloxane of (A), various organic groups represented by R above can be used, but a methyl group is preferable, and 50 mol% or more of R is methyl group. It is preferably a group.

A typical example of the organohydrogenpolysiloxane of (A) above is represented by the formula: [(CH ₃ ) ₃ SiO _0.5 ] a [(CH ₃ ) ₂ HSiO _0.5 ] b [(CH ₃ ) ₂ SiO]. c [CH ₃ HSiO] d [where a and b are integers from 0 to 2, where a + b =
2, c is an integer of 0 to 500, and d is an integer of 0 to 50. ] The thing represented by is mentioned.

The aliphatic unsaturated group-containing organopolysiloxane (B) contains, on average, 1.5 or more, preferably 2 to 5 aliphatic unsaturated groups bonded to a silicon atom in one molecule. . Examples of the aliphatic unsaturated group include a vinyl group and an allyl group, but a vinyl group is generally preferable. Examples of the organopolysiloxane include (CH ₂ = CH) SiO _1.5 units, RSiO _1.5 units, R (CH ₂ = CH) SiO units, R ₂ SiO units, R ₂ (CH ₂ = CH) SiO _0.5 units, R ₃ SiO _0.5 unit, [where
R is as described above. ] And the like.

The molecular structure of the organopolysiloxane (B) may be linear, branched, or cyclic, but linear is more preferable in order to facilitate the addition polymerization reaction. .

The organopolysiloxane (B) has an average of 1.5 or more, preferably 2 to 5, aliphatic unsaturated groups bonded to a silicon atom in one molecule.

Further, the content of the aliphatic unsaturated group, for example, vinyl group is 0.5 to 50 mol% in the organic group bonded to silicon, particularly 1 to 20%.
It is preferably in mol%. A preferable organic compound other than the aliphatic unsaturated group is, for example, methyl, and it is particularly desirable that 50 mol% or more of the other organic group is a methyl group.

A typical example of the organopolysiloxane of the above (B) is represented by the formula: [(CH ₂ = CH) (CH ₃ ) ₂ SiO _0.5 ] e [(CH ₃ ) ₃ SiO _0.5 ].
f [(CH _{3) 2} SiO] g _{[(CH 2 = CH) CH 3} SiO ] h [wherein, e and f are integers of 0 to 2, provided that e + f =
2, g is an integer of 0 to 500, and h is an integer of 0 to 50. ] Methyl vinyl polysiloxane represented by
It may be a mixture of these and can be suitably used in the present invention.

As described above, in both the organohydrogenpolysiloxane of (A) and the organopolysiloxane of (B), one molecule of a hydrogen atom or an aliphatic unsaturated group bonded to silicon, which is each reactive group, It is necessary that the average number is 1.5 or more, but if either of these is less than 1.5, it becomes difficult to form a three-dimensional structure in the polymer obtained by addition polymerization, and the desired powder form is obtained. Is difficult.

The content of these reactive groups is preferably 0.5 to 50 mol% in each of the polysiloxanes (A) and (B), but when the content is more than 50 mol%, the crosslinking density becomes high. Since the obtained silicone powder becomes too hard, it is difficult to disintegrate into fine particles when compounded and molded into a thermoplastic resin, and as a result, a thermoplastic resin composition in which fine particles are uniformly dispersed cannot be obtained. Further, the silicone oil (C) is less likely to be encapsulated in the polymerization product and tends to bleed out on the surface, making it difficult to stably retain (C) in the silicone powder. On the other hand, when the content of the reactive group is less than 0.5 mol%, the formation of the three-dimensional crosslinked structure is insufficient and it becomes difficult to obtain a silicone powder in the form of a powder that is easy to handle.

In a further preferred embodiment of the present invention, at least one of (A) the organohydrogenpolysiloxane and (B) the aliphatic unsaturated group-containing organopolysiloxane,
Reactive group content is less than 20 mol%. In this preferred embodiment, the cross-linking density of the polymer obtained by addition polymerization is in a suitable state, and it tends to collapse and become fine as a result. The particles are easily dispersed uniformly in the thermoplastic resin matrix.

The silicone oil (C) used in the present invention is 25
If the viscosity at 100C is 100 cSt or less, it can be used without particular limitation. If this viscosity exceeds 100 cSt t, the molecular radius becomes too large, so that it is not retained in the three-dimensional cross-linking space of the addition polymer obtained by the addition polymerization of (A) and (B), that is, surface bleeding occurs. However, a uniform silicone powder cannot be obtained.

Examples of the silicone oil (C) include a chain having a low degree of polymerization,
Or branched methylpolysiloxane, methylphenylpolysiloxane, ethylpolysiloxane, ethylmethylpolysiloxane, ethylphenylpolysiloxane, cyclic octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and the like may be used. 1 type or 2 types or more of these are appropriately selected and used.

The production of silicone powder as a component of the composition of the present invention is
In the presence of the silicone oil of (C), the organohydrogenpolysiloxane of (A) and the organopolysiloxane of (B) are subjected to addition polymerization with stirring. At this time, the silicone of (C) is used. The proportion of oil is
It is in the range of 1 to 200 parts by weight, preferably 10 to 100 parts by weight, based on 100 parts by weight of the total amount of the organohydrogenpolysiloxane (A) and the organopolysiloxane (B). This is because when the proportion of silicone oil is less than 1 part by weight, even if the obtained silicone powder is blended with a thermoplastic resin, the effect of improving the abrasion resistance of the obtained thermoplastic resin composition is poor, and the content is 200 parts by weight. If the amount is larger, the silicone oil (C) bleeds out on the surface of the silicone powder, making it difficult to handle. Since the silicone powder obtained by polymerizing in the presence of the (C) silicone oil does not bleed out the (C) silicone oil on the surface, it can be blended and molded into a thermoplastic resin. It's extremely easy. Further, the obtained thermoplastic resin molded article is not only improved in impact resistance by the silicone powder, but also has excellent abrasion resistance because the encapsulated (C) silicone oil imparts the effect of improving lubricity. Becomes

The ratio of the organohydrogenpolysiloxane of (A) and the organopolysiloxane of (B) to be subjected to the addition polymerization is such that the hydrogen atom bonded to the silicon atom of (A) / the silicon atom of (B). The molar ratio of the aliphatic unsaturated group bonded to is preferably in the range of 1/3 to 3/1, particularly
The range of 1/2 to 2/1 is preferable. If this ratio is too large or too small, unreacted components (hydrogen atoms bonded to silicon atoms or aliphatic unsaturated groups) remain in the polymerization product, resulting in impaired stability of the final composition. Be done.

The addition polymerization is carried out by using an organic solvent such as an aliphatic alcohol such as methanol, ethanol, 2-propanol and butanol, an aromatic hydrocarbon such as benzene, toluene and xylene, an aliphatic hydrocarbon such as n-pentane, n-hexane and cyclohexane. Platinum compounds soluble in halogenated hydrocarbons such as alicyclic hydrocarbons, dichloromethane, chloroform, carbon tetrachloride, trichloroethane, trichloroethylene, and fluorinated chlorohydrocarbons (for example, chloroplatinic acid, alcohol-modified platinic acid, chloroplatinic acid) -Vinylsiloxane complex) or a rhodium compound in the presence of a room temperature or under heating (about 50 to 150 ° C).

As a catalyst, chloroplatinic acid, US Pat.
Examples of the platinum compound used in the hydrosilylation reaction described in 3,159,601, 3,159,662, 3,775,452 and the like, such as [Pt (PPh ₃ ) ₃ ], are vinyl, for example. It is preferable to use a complex compound of siloxane and a platinum compound, and further a compound obtained by modifying this with alcohol. Among them, chloroplatinic acid described in JP-B-33-9969 or a complex compound of vinylsiloxane and chloroplatinic acid is more preferable.

The specific operation of the addition polymerization is carried out by using a reactor equipped with an appropriate stirrer, such as a planetary mixer, and blending the respective organopolysiloxanes of (A), (B) and (C), Further, a catalyst may be added, and if necessary, heated and stirred, and in this addition polymerization reaction, what was in a liquid state at the beginning is thickened within a very short time and further soft block body and further It collapses into powder, but these appear as a series of phenomena. Therefore, the silicone, which is a polymerization product obtained by this addition polymerization, is usually obtained as a powder.

The polymerization product thus obtained is ground under a shearing force to obtain a fine powder in order to obtain a uniform powder that can be further used. For this purpose, an appropriate shearing force imparting device such as a three-roll mill, a two-roll mill, a sand grinder, a ball mill or the like is used.

The silicone powder finally obtained in this manner is a white powder with an irregular particle size of 10 to 500 μm and less stickiness, smooth to the touch, and rubbed between fingers.
Furthermore, it has the property of disintegrating into fine particles.

As the thermoplastic resin to be added and blended with the silicone powder obtained as described above, for example, polystyrene, AS resin, ABS resin, polyvinyl chloride, vinylidene chloride-vinyl chloride copolymer resin, polyacetic acid. Examples thereof include vinyl, vinyl chloride-vinyl acetate copolymer resin, polyethylene, polypropylene, polyacetal, polyamide, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, and acrylic resin.

The silicone powder may be blended with these thermoplastic resins by a known method using a device represented by, for example, a Henschel mixer, a super mixer, a raker machine, or a V-type blender.

Further, the molding method of the composition of the present invention obtained by blending is not particularly limited, for example, extrusion molding, injection molding, calender molding, blow molding, compression molding, transfer molding, etc., depending on the type of thermoplastic resin, It may be selected according to the form of the molded product.

〔Example〕

The present invention will be further described with reference to examples. These do not limit the present invention at all.

In the following, the viscosities are at 25 ° C.

[Production Example 1] A planetary mixer having an internal volume of about 5 was charged with 650 g of trimethylsilyl end-blocked dimethylmethylhydrogenpolysiloxane A (average molecular weight: 2180, Si-H content: 6.5 mol%).
g, dimethylvinylsilyl end-capped dimethylpolysiloxane A (average molecular weight 930, vinyl group content 7.7 mol%) 54
9g and octamethylcyclotetrasiloxane (2.3cSt)
800 g were mixed with stirring.

0.5 g of a 2% isopropanol solution of chloroplatinic acid was added to the obtained mixed solution, and stirring was continued at 70 to 80 ° C for 2 hours. As a result, a powder having white flexibility was obtained.

This powder was further pulverized with a three-roll mill to obtain a uniform white powder (powder A).

[Production Example 2] White color was exactly the same as in [Production Example 1] except that trimethylsilyl end-blocked dimethylpolysiloxane A (20cSt) 514 g was used in place of octamethylcyclotetrasiloxane 800 g in [Production Example 1]. A powder (powder B) was obtained.

[Manufacturing Example 3] [Manufacturing Example 1] In the same manner as in [Manufacturing Example 1] except that trimethylsilyl end-capped dimethylpolysiloxane B (50 cSt) 514 g was used in place of octamethylcyclotetrasiloxane 800 g in [Manufacturing Example 1]. A white powder (powder C) was obtained.

[Example 1] [Comparative Example 1] The "powder A to C" obtained in [Production Examples 1 to 3] were
Resin HF77 (Made by Mitsubishi Monsanto Co., Ltd.)
Blend at the blending ratio of 1) and use a Raikai machine for 30 minutes at room temperature.
After mixing with a vertical injection molding machine with an inner diameter of 22 mm,
Molded under the molding conditions described above to obtain a 100 × 130 × 2 mm thick film.
I got a template.

・ Injection pressure: 300kg / cm ²・ Screw rotation speed: 110rpm ・ Heater temperature: (upper) 250 ℃ (lower) 230 ℃ (nozzle) 230 ℃ ・ Mold temperature: 50 ℃ ・ Injection time: 10 seconds ・ Cooling time: 20 seconds The time required for the screw to return during molding was not delayed by the addition of "powder A to C". On the contrary, the mold release from the mold was greatly improved and the moldability was improved. .

The obtained molded plate was cut into 30 × 30 mm to give an impact resistance test piece. Impact resistance was evaluated by dropping a 62 g steel ball to the center of the test piece from the height shown in the table and observing the number of pieces to be broken. The results are shown in (Table-1).

A significant improvement in impact resistance was observed in the example in which "powder A to C" was blended, as compared with the case where "powder A to C" was not blended (Comparative Example 1).

Further, a wear resistance test piece of 27 mm × 27 mm was prepared from the molded plate, and a wear resistance test was conducted under the following test conditions. This test was also carried out on the samples not containing "powder A to C" (Comparative Example 1).

・ Testing machine: Toyo Baldwin Co., Ltd. friction tester "EFM-III-B" ・ Friction cell: Carbon steel S45C cylindrical type (inner diameter 20.0mm, outer diameter 25.6)
mm, height 16.0 mm) -Cell friction surface average roughness: 2 to 3 μm-Friction cell rotation speed: 200 rpm-Friction time: 10 minutes The results obtained are shown in (Table-1).

It is recognized that not only the impact resistance but also the abrasion resistance is significantly improved in the case of adding and blending "powder A to C".

[Effects of the Invention] The thermoplastic resin composition of the present invention does not require a complicated process or a special device, has good moldability, and has excellent impact resistance and abrasion resistance. can get.

Claims (1)

[Claims] 1. A thermoplastic resin of 100 parts by weight, an organohydrogenpolysiloxane of the following (A) and an organopolysiloxane of the following (B) are added to the following (C):
Of 1 to 50 parts by weight of the amorphous silicone powder obtained by pulverizing the resulting polymerization product under shearing in the presence of silicone oil under agitation Plastic resin composition. (A) An organohydrogenpolysiloxane containing an average of 1.5 or more hydrogen atoms bonded to silicon atoms in one molecule. (B) Organopolysiloxane containing an average of 1.5 or more aliphatic unsaturated groups bonded to silicon atoms in one molecule. (C) Silicone oil whose viscosity at 25 ° C is 100 cSt or less:
1 to 200 parts by weight based on 100 parts by weight of the total amount of the organohydrogenpolysiloxane (A) and the organopolysiloxane (B).