JPH01201351A - Styrene resin composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a styrenic resin composition with excellent sliding properties. More specifically, the present invention relates to a styrene resin composition with excellent sliding properties, which is made by blending a styrene resin with silicone oil and a tin stabilizer.

[Conventional technology]

Currently, with the advancement and diversification of industry, there is active development of technology to improve the physical properties of various general-purpose thermoplastic resins by blending them with various additives. In particular, methods of mixing additives into resins for the purpose of improving the surface lubricity of the resins are popular. Specifically, well-known methods include mixing additives such as graphite, carbon fiber, and silicone oil, and blending resins with excellent sliding properties such as polyamide resin, polyaceter, and resin.

Furthermore, materials with excellent sliding properties are used in various industrial parts. Generally, it is widely used in sliding parts such as gear cams and bearings, and in building materials such as aluminum sash pulleys.

Furthermore, in the fields of electrical equipment and electronic equipment, materials with similar excellent sliding properties are being developed in a wide variety of ways. Specifically, there are reels and rollers for audio and video cameras, reels for video tape records (VTR), and various sliders.

These various materials have different sliding characteristics. In particular, synthetic resins such as polyacetal resin and polyamide resin are known to have good sliding properties. However, these synthetic resins are not only expensive in material cost and limited in terms of product use, but also have a high molding shrinkage rate and poor dimensional accuracy.

[Problem to be solved by the invention]

In order to solve these problems, attempts have been made to modify the resin by using a styrene resin with excellent dimensional stability and adding various additives. Specifically, it is known that a material with improved sliding properties can be obtained by mixing silicone oil into impact-resistant polystyrene, acrylonitrile-butadiene-styrene terpolymer (ABS resin), or the like. However, when producing products by injection molding using materials mixed with silicone oil, "burn marks" may occur, which is thought to be caused by the silicone oil. Although there are slight variations in the "burnout" phenomenon depending on the specifications of the injection molding machine, molding conditions, etc., the probability of it occurring is high.
This results in product defects and significantly reduces product yield.

As mentioned above, the mechanism by which "burning marks" occur in molded products due to the addition of silicone oil is unknown, but according to conventional knowledge, effective measures against "burning marks" include changing the conditions during the molding process, such as changing the resin temperature. Measures were taken to reduce the amount of water, increase back pressure, and reduce screw rotation speed. However, these methods could not provide a complete solution.

From the above, the present invention does not have these drawbacks (problems), that is, it has excellent sliding properties, does not cause the phenomenon of burnout of molded products, and has excellent mechanical and thermal properties. The object of the present invention is to obtain a styrenic resin composition with almost no deterioration.

[Means and effects for solving the problems] According to the present invention, these problems are a composition consisting of (A) a styrene resin, (B) a silicone oil, and (C) a tin-based stabilizer; A styrenic resin composition in which the proportion of silicone oil in the composition is 0.3 to 5.0% by weight, and the proportion of tin stabilizer in the composition is 0.05 to 3.0% by weight. It can be solved. The present invention will be explained in detail below.

(A+ Styrenic resin The styrene resin used in the present invention is a rubber selected from the group consisting of butanoene rubber, ethylene-glopylene rubber, and acrylic ester rubber, and styrene alone, styrene and acrylonitrile, or styrene and methyl methacrylate. and "styrene homopolymer resins and copolymer resins of styrene and other monomers" (hereinafter referred to as "styrenic polymer resins").

(1) Impact-resistant resin The rubber used in the production of the impact-resistant resin in the present invention is a butadiene homopolymer rubber and a random or block copolymer rubber of butadiene and a low M (usually 40% by weight or less) styrene or acrylonitrile. Butanoene rubber, copolymer rubber of ethylene and zoropyrene, and small amounts of ethylene and zoropyrene (generally,
(10% by weight or less), straight-chain or branched olefins containing two double bonds at the ends (e.g. 1,4-pentadiene); Ethylene-zolopyrene rubbers selected from multicomponent copolymer rubbers with olefins (e.g., ) or an acrylic ester rubber obtained by polymerizing a small amount (generally 10% by weight or less) of this ester with another element (for example, acrylonitrile).

In producing the impact-resistant resin of the present invention, among these rubber-like substances, those having a Mooney viscosity of 20 to 140 are preferable, although it varies depending on the type of the rubber-like substance, and those having a Mooney viscosity of 30 to 120 are particularly preferable. It is. Further, these rubber-like materials are widely produced industrially and are used in a wide variety of fields. Their manufacturing methods, properties and uses are widely known.
For example, Shu Kambara, ``Synthetic Rubber Ndpukku'' (published by Asakura Shoten in 1962).

In producing the impact-resistant resin of the present invention, graft polymerization methods include bulk polymerization, solution polymerization, emulsion polymerization, aqueous suspension polymerization, and methods that combine these graft polymerization methods (for example, bulk polymerization). There is a method of carrying out aqueous suspension polymerization after polymerization.

Generally, the amount of rubber material used to produce 100 parts by weight of impact-resistant resin is 1 to 40 parts by weight,
2 to 35 parts by weight is preferred, and 3 to 30 parts by weight is particularly preferred (a relatively large amount of rubber-like material is used to produce a graft polymer containing a large amount of rubber-like material, and this graft polymer is The above-mentioned homopolymer resins or copolymer resins of styrene, acrylonitrile, and methyl methacrylate may be mixed, but in this case, the amount of the comb-like material used is calculated based on the mixture.) In addition, monomers (styrene, acrylonitrile,
The molecular weight of methyl methacrylate is usually 1000 to 4.
00,000, especially between 2000 and 300,000
0 is desirable. In general, complete bonding of monomers to the rubber is rare, and there are grafts and homopolymers or copolymers of monomers that are not bonded to the rubber. These homopolymers and copolymers are used alone without separation. Typical examples of impact-resistant resins produced as described above include styrene homopolymer rubber or block or random copolymers of styrene and butanoene. High impact polystyrene (HIPS) obtained by graft polymerizing styrene onto rubber, butadiene homopolymer rubber, block or random copolymer rubber of styrene and butadiene (
Acrylonitrile-butadiene-styrene terpolymer resin (ABS resin) obtained by graft copolymerizing styrene and acrylonitrile onto acrylonitrile and butadiene copolymer rubber (NBR) or acrylonitrile and butadiene copolymer rubber (NBR)
, methyl methacrylate-butadiene-styrene ternary copolymer resin (MBS resin) obtained by graft copolymerizing styrene and methyl methacrylate to butadiene homopolymer rubber or SDR, acrylonitrile and styrene grafted to acrylic acid ester rubber Acrylonitrile-acrylic acid ester-styrene ternary copolymer resin (AAS resin) obtained by copolymerization
and a graft copolymer resin (AES resin) obtained by graft copolymerizing 7-crylonitrile and styrene to ethylene-propylene rubber.

Furthermore, in the production of the above impact resistant resin, a relatively large amount (generally 40 to 70% by weight) of rubber is graft copolymerized with styrene and acrylonitrile or styrene and methyl methacrylate in the same manner as in the production of the impact resistant resin. Using the impact-resistant resin with a high rubber concentration (for example, acrylonitrile-butadiene-styrene ternary copolymer resin with a high rubber concentration), the heat-resistant resin described above, and the styrene copolymer resin described later, The ratio may be adjusted within a range.

These impact-resistant resins are manufactured industrially and are used in a wide variety of fields. Moreover, the manufacturing method is well known.

(2) Styrenic polymer resin.

Further, the styrene polymer resin used as the styrene resin includes a styrene homopolymer resin and a copolymer resin of styrene and other monomers. Other monomers include
Acrylonitrile, acrylic acid and methacrylic acid and their methyl or ethyl esters (e.g.
methyl methacrylate), donylpyridine and vinylcarbazole. Among these styrene-based polymer resins, the copolymerization ratio of styrene in the copolymer resin is generally at least 40% by weight (preferably 50% by weight).
L% or more).

This styrene-based copolymer resin is industrially produced by a polymerization method similar to the above-mentioned graft polymerization, and is used in a wide variety of fields.

Melt flow index (JIS
Measured according to K7210 under conditions 8, hereinafter rMF
R,,1) is generally from 0.2 to 509/10 minutes, preferably from 0.5 to 405'/10 minutes. If a styrene resin with an MFR of less than 0.2 g/10 minutes is used, moldability will be poor. On the other hand, if a styrene resin exceeding 50 g and 710 minutes is used, the resulting composition will have poor mechanical strength.

(B) Silicone Oil Also, examples of the silicone oil used in the present invention include those whose general formulas are represented by the following formulas [(■) to m)].

In formulas (1) to (■), φ is a phenyl group, and X and y may be the same or different, and are 0 or an integer from 1 to 2,000.

The silicone oil is preferably selected from those having a viscosity in the range of 50 to 70,000 e/s at a temperature of 25°C. If a silicone oil has a viscosity of less than 50 c/s at a temperature of 25° C., it is unsuitable because its flash point is close and there is a great risk of fire when mixed with styrene resin. On the other hand, 70,00
If a material exceeding 0 C/8 is used, the viscosity will be too high and there will be problems in handling.

(C) Tin-based stabilizer Furthermore, examples of the tin-based stabilizer used in the present invention include those represented by the following formula [formula (■)].

Representative examples of the tin-based stabilizers include dibutyltin maleate, dioctyltin maleate, dibutyltin laurate methyl maleate, and dibutyltin dilauryl mechagetide.

(D) Composition ratio The composition ratio of silicone oil in the styrenic resin composition of the present invention is 0.3 to 5.0% by weight, and 0.5% by weight.
-4.0% by weight is preferred, especially 0.5-3.5% by weight
is suitable. If the proportion of silicone oil in the composition is less than 0.3% by weight, the effect of the tin-based stabilizer blended is not significant.

On the other hand, if it exceeds 5.0% by weight, the properties of the resulting composition will be significantly reduced.

In addition, the composition ratio of the tin-based stabilizer in the composition is 0.
．． 05 to 3.0% by weight, and 0.05 to 2.5% by weight
is desirable, particularly 0.1 to 2.0 weight ffi%. The composition ratio of the tin-based stabilizer in the composition is 0.
．． If the amount is less than 0.05% by weight, the effect of the blend is not good. on the other hand,
If it exceeds 3.0% by weight, the properties of the resulting composition will be significantly reduced.

(E) Method for producing and molding composition The composition of the present invention can be obtained by uniformly mixing the styrene resin, silicone oil, and tin stabilizer. At this time, it is also possible to produce a composition by mixing a roughened styrene resin and silicone oil, and to tri-blend a tin-based stabilizer when molding the resulting composition, and the effect can be sufficiently exerted. .

In producing the composition of the present invention, it can be obtained by uniformly blending the above composition components in the above composition ratio, but antioxidants and ultraviolet absorbers commonly used in the field of styrenic resins , colorant,
Additives such as antistatic agents, effacers, and fillers may be added to the extent that they do not essentially impair the properties of the compositions of the present invention.

To produce the composition of the present invention, triblending may be performed using a mixer such as a Henschel mixer commonly used in the field of thermoplastic resins.
Melt kneading may be performed using a mixer such as a Banbury mixer, roll mill, or screw extruder. At this time, a more uniform composition can be obtained by tri-blending the mixed components in advance and further melt-kneading the resulting mixture.

Furthermore, in producing the composition, all the composition components may be mixed simultaneously, or a part of the composition components may be mixed in advance to produce a so-called masterbatch, and the resulting masterbatch and the remaining composition components may be mixed together. You may also mix them.

K, in which a product is produced by molding the composition obtained as described above, can be achieved by molding by injection molding, which is commonly practiced in the field of styrenic resins.

Even when melt-kneading to produce the above composition,
Even when injection molding is used, it must be carried out at a temperature that melts the styrene resin used. but,
If carried out at high temperatures, the styrenic resin may thermally decompose. From these reasons, generally 180 to 300
What is necessary is just to carry out at degreeC (suitably 190-260 degreeC).

[Examples and comparative examples]

Hereinafter, the present invention will be explained in more detail with reference to Examples.

In the Examples and Comparative Examples, tensile yield strength and elongation were measured according to JIS K6871, and Izo impact strength (notched) was measured according to ASTM D256. In addition, the bending elastic modulus is ASTMD79
Rockwell hardness (L scale) was measured according to ASTM D785. Additionally, heat distortion temperature was measured according to ASTM D648. In addition, the test piece was created by injection molding at a resin temperature of 220°C. In addition, the "burning" test was performed using an injection molding machine (manufactured by Japan Steel Works, Model 100BII) under the following conditions.

Resin temperature See Table 2 Filling speed FCV max Injection pressure Primary pressure 80 Yu/Yu2 Secondary pressure 40 to 60 kl? /(?l+2 Measuring rotation speed 200 rotations Measuring 23m Back pressure 1 0 kg7cm2 Also,
The product is a flat plate (thickness 2 wa, 35 x 70 w)
) to adjust the weight of the molded product to 16g ± 1g. Note that the mold temperature was fixed at 30°C.

The manufacturing method, physical properties, etc. of the styrene resin, silicone oil, and tin stabilizer used in Examples and Comparative Examples are shown below.

[(A) Styrenic resin]

As the styrenic resin, impact-resistant polystyrene (MFR 3,0! J/10
(hereinafter referred to as "HIPS"), styrene homopolymer (MFR2, 1/10 minutes, hereinafter referred to as rPsJ), and ABS resin manufactured as follows.

20! 550 g (as solid content) of polybutadiene latex rubber (containing 80%) in a stainless steel autoclave, 160 g of ammonium persulfate of 2.
of disproportionated sodium rosinate, 21.0 g of lauryl mercagutan and 8. Oj of water was added and stirred evenly. This includes 27909 styrene and 93 monomers.
5 g of acrylonitrile was added and stirred, and then the temperature was raised to 70°C while stirring. Polymerization was carried out at this temperature for 10 hours with stirring. A 5% aqueous solution of aluminum sulfate was then added to the latex containing the t-polymer (grafted material) obtained as described above to coagulate the resulting grafted material. This coagulated material is dissolved in water with approximately 1% sodium hydroxide for approximately 5.271%! Wash using
Further, it was washed using multi-N (approximately 301) (7) flooded water at 70°C. This graft material was dried at about 80° C. under reduced pressure all day and night. As a result, a grafted product of 3925.9 white powder was obtained. The obtained graft had an Izot impact strength of 7.5 kg-cm/cm-notch and a tensile strength of 468 kg/m2. Moreover, the Vicat softening point of this polymer was 95.0°C.

The content of rubbery substances in this graft was 15.0% by weight.

Hereinafter, this graft product will be referred to as rABsJ.

[(B) Silicone oil]

In addition, as a silicone oil, dimethylpolysiloxane with a viscosity of 30,000 c/s at 25°C [
Hereinafter referred to as "Silicone (1)"], dimethyl having a viscosity of 3,000 c/s at 25°C, 1? Resiloxane [hereinafter referred to as "Silicone (2) J]" and 2
Dimethylpolysiloxane having a viscosity of 60,000 c/s at 5°C [hereinafter referred to as "silicone (3)"]
was used.

[(C) Tin-based stabilizer]

Furthermore, as a tin-based stabilizer, dibutyltin malate [
Dioctyltin malate (hereinafter referred to as "stabilizer (B)") and dibutyltin dilauryl mercazotide (hereinafter referred to as "stabilizer (C)") were used.

Examples 1 to 4, Comparative Examples 1 to 6 The styrene resin, silicone oil, and tin stabilizer whose compounded poisons are shown in Table 1 were triblended in advance for 5 minutes using a Henschel mixer (JI201). I did it. Each of the obtained mixtures was heated to a resin temperature of 210°C using a co-directional twin-screw extruder (diameter 30 m).
Each composition was manufactured by cross-talking under the following conditions.

Each test piece was prepared using each of the obtained compositions under the above conditions,
When measuring the physical properties, a flat plate molded product was produced by injection molding in the same manner, and "scorch marks" on the external surface were visually observed. The results are shown in Table 2.

[Effects of the Invention] The styrenic resin composition of the present invention exhibits the following effects.

(1) It is possible to prevent "burning marks" during injection molding that occur when silicone oil is mixed.

(2) The tin stabilizer used does not impair the basic properties of the composition of the present invention.

The styrenic resin composition of the present invention can be used in a wide variety of ways in order to exhibit the above effects.

Typical uses are shown below.

(1) Sliding parts such as gears and cams (2) Video Chi! , Audio Teso reel (3) Video Chi recorder reel (4)
Each Aki slider patent applicant Showa Denko K.K.

Claims (1)

Scope of Claims: A composition comprising (A) a styrene resin, (B) a silicone oil, and (C) a tin-based stabilizer, and the composition ratio of the silicone oil in the composition is 0.3 to 5. 0% by weight, and the composition ratio of the tin-based stabilizer is 0.05 to 3.0% by weight.