JPH032251A - Permanently antistatic impact-resistant resin composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition, composed of a rubber-reinforced vinyl aromatic polymer modified with a carboxyl group-containing monomer and a polyether with a specific molecular weight, etc., having permanent antistatic properties and excellent in impact resistance. CONSTITUTION:The objective composition obtained by blending (A) 100 pts.wt. rubber-reinforced vinyl aromatic polymer modified with a monomer containing 0.1-5wt.% carboxyl groups with 100 pts.wt. total amount of (B) 4-20 pts.wt. polyether (e.g. polyethylene glycol), expressed by formula I (R is H or CH3; n is a number determined by the average molecular weight) and having >=20000 average molecular weight and (C) 0.1-5 pts.wt. alkali metal salt of an alkylsulfonic acid or alkylbenzenesulfonic acid expressed by formula II (R is H or alkyl: M is alkali metal, such as Li, Na or K), preferably (D) 0.005-0.1 pt.wt. organopolysiloxane (e.g. polydimethylsiloxane) and (E) 0.1-1 pt.wt. metal salt of a higher fatty acid.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermoplastic resin composition having permanent antistatic properties. More specifically, the present invention relates to a thermoplastic styrenic resin composition that has permanent antistatic properties and excellent impact resistance.

[Conventional technology and its problems]

High impact polystyrene (hereinafter referred to as HIPS).

) or rubber-reinforced thermoplastic resin, also known as ABS resin, has excellent moldability, dimensional stability, impact resistance, and electrical insulation properties, so it is used as a molding material for a wide range of applications, including electrical products and office equipment. It is used. however,
HIPS and ABS resins, like other plastics for molding, are easily charged with electricity, and as a result, dirt and dust can be attracted to the surface of the molded product, damaging the appearance of the product. In some cases, there have been problems such as inability to function properly due to attached dust.

The conventional methods used to solve these problems are (1) the method of applying an antistatic agent to the surface of the molded product (2)
, a method of kneading an antistatic agent into a thermoplastic resin material for molding (3), and a method of chemically modifying the structure of the resin.

However, method (1) not only requires a step of applying an antistatic agent in addition to the molding step, but also has the disadvantage that the antistatic effect deteriorates due to changes over time or washing. In addition, method (2) does not require a coating process, which solves the problem of decreased productivity, but it also causes stains on the surface of the molded product due to bleed-out of the antistatic agent that has been kneaded in, deterioration of the appearance, and There have been problems such as a decline in the antistatic effect due to changes in the antistatic agent incorporated over time.

Furthermore, regarding method (3), for example, a method of mixing a styrene resin modified with a carboxyl group and a polyalkylene oxide or a derivative thereof (US Pat. No. 29
12413 specification, German Patent No. 3203488, JP-A-59-142242), ethylenically unsaturated monomers and ethylenically unsaturated monomers having a conjugated diene or acrylic acid ester and an alkylene oxide group A resin composition comprising a graft copolymer obtained by graft copolymerizing an ethylene monomer to a rubber base polymer, a compatible thermoplastic resin, and a surfactant (Japanese Patent Laid-Open No.
-118446), a composition prepared by blending a styrene resin with a copolymer of a vinyl monomer and a monomer containing an alkylene oxide group, and a metal salt dissolved therein (JP-A-118446); 62-158742), a graft copolymer obtained by graft polymerizing a vinyl monomer and a monomer containing an alkylene oxide group to a diene rubber latex, and a sulfonic acid or carboxylic acid having a perfluoroalkyl group. A resin composition comprising a monovalent metal salt of an acid (Japanese Unexamined Patent Publication No. 62-207352) has been proposed.

However, the above-mentioned US Pat. No. 2,912,413, German Patent No. 3,203,488 and JP
In the method of Publication No. 9-142242, since hydrophilic polyalkylene oxide is used as a means for imparting antistatic properties, the effect is greatly affected by the humidity of the environment.
Another problem is that the effect will not be seen unless a sufficient amount of polyalkylene oxide is added, and in addition, as a result of using low molecular weight polyalkylene oxide, the impact strength and heat resistance of the composition will decrease. was there. JP-A-56118446, JP-A-62-15874
No. 2 and JP-A No. 62-207352 achieve semi-permanent antistatic properties, but they do not use a relatively large amount of expensive wood-loving 7-summer (alkylene oxide group-containing monomer). Since it is necessary to use such a method, the cost of the final composition becomes extremely high, and there is a problem in that it is difficult to obtain a composition with high impact strength.

[Means to solve the problem]

The inventors of the present invention have conducted intensive studies with the aim of providing a thermoplastic resin that has permanent antistatic properties, excellent impact resistance, and is inexpensive. The present inventors have discovered that a composition comprising a rubber-reinforced vinyl aromatic polymer, a polyether of a specific molecular weight, and an alkali metal salt of an alkylsulfonic acid or an alkylbenzenesulfonic acid achieves the above object, and has completed the present invention. .

That is, the first invention of the present invention provides (A) a rubber-reinforced vinyl aromatic heavy body modified with a monomer containing a carboxyl group, and (B) a rubber-reinforced vinyl aromatic heavy body modified with a monomer containing a carboxyl group; Below polyether Margin R (However, R is H or CH3, n is an integer determined by the average molecular weight.) (C) Alkali metal salt of alkylsulfonic acid or alkylbenzenesulfonic acid represented by the following formula R-S03M R+s03M (However, , R is M or an alkyl group, and M is Li.

Alkali metals such as Na, etc. ) A second invention is a permanently antistatic impact resistant resin composition characterized by comprising: a permanently antistatic impact resistant resin composition comprising an organopolysiloxane contained in the composition;
The present invention is a permanently antistatic, impact-resistant resin composition in which the first invention composition contains an organic polysiloxane and a metal salt of a higher fatty acid.

The characteristics of the present invention are that polyethers which, when used alone, do not exhibit an antistatic effect at the practically required level in the amount used in the present invention, and polyethers that, when used alone, do not exhibit antistatic effects. By coexisting with alkyl sulfonic acid or alkali metal salt of alkylbenzene sulfonic acid, which exhibits almost no antistatic properties, surprisingly high antistatic properties can be achieved.
Moreover, although the mechanism is not clear, it exhibits permanent antistatic performance.

In the present invention, (A) a rubber-reinforced vinyl aromatic polymer modified with a monomer containing a carboxyl group (hereinafter referred to as
Abbreviated as acid-modified rubber reinforced resin. ) and (B) polyether form a moderately compatible system through hydrogen bonding, and as a result, they impart good antistatic properties without impairing the mechanical properties of the acid-modified rubber-reinforced resin. It is thought that there are. Furthermore, the coexistence of (B) polyether and CC) alkali metal salt of alkylsulfonic acid (hereinafter referred to as metal salt) imparts permanent antistatic properties to the composition, although the reason for this is not clear. It has the effect of imparting sex. Therefore, in the present invention, even if any of the components (A) acid-modified rubber reinforcing resin, (B) polyether, and (C) metal salt is missing, the intended purpose cannot be achieved.

The resin composition of the present invention has impact resistance equal to or higher than that of the acid-modified rubber reinforced resin that is the basic resin, but also has the above-mentioned (
By blending a small amount of an organic polysiloxane or an organic polysiloxane and a metal salt of a higher fatty acid into the blend of A), (B), and (C), a resin composition with even higher impact strength can be obtained.

The resin composition of the first aspect of the present invention has impact resistance equal to or higher than that of the basic acid-modified rubber reinforced resin, and further contains a small amount of organic polysiloxane or the organic polysiloxane and higher fatty acid salt. By blending it into the resin composition of the invention, a resin composition with further improved impact resistance can be obtained.

The acid-modified rubber reinforcing resin used in the present invention is composed of one or more vinyl monomers whose main component is a vinyl aromatic monomer, and a vinyl monomer having a carboxyl group in the molecule. This is a polymer obtained by graft copolymerization of a mixture and a rubbery polymer. The carboxyl group referred to in the present invention may be an anhydrous carboxyl group. The amount is preferably adjusted so that the content of the carboxyl group-containing monomer in 100 parts by weight of the acid-modified rubber reinforcing resin is 0.1 to 5% by weight.

As the carboxyl group-containing monomer, vinyl monomers having a carboxyl group or carboxyl anhydride such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, phthalic acid, and itaconic acid are used. Also,
Vinyl aromatic monomers used together with the above carboxyl group-containing monomers include single vinyl aromatic monomers such as styrene and α-methylstyrene, and monomers copolymerizable with these monomers. cyanide vinyl monomers such as acrylonitrile and methacrylonitrile,
(meth) such as methyl methacrylate, butyl acrylate, etc.
A small amount of an acrylic acid ester monomer or the like can be used in combination. Furthermore, as the rubbery polymer, polybutadiene, styrene-butadiene copolymer rubber (SBR),
Conventional rubbery polymers such as styrene acrylonitrile copolymer rubber (NBR) can be used.

The polymerization method of the acid-modified rubber reinforcing resin is not particularly limited, and the vinyl monomer and the vinyl monomer having a carboxyl group are subjected to bulk polymerization, bulk/suspension polymerization, or emulsification in the presence of the rubbery polymer. Graft copolymerization may be carried out according to a conventional method such as polymerization. In addition to the method of direct polymerization as described above,
There is a method in which a rubber reinforced vinyl aromatic polymer with a high rubber content and a high carboxyl group content is prepared in advance and mixed with a vinyl aromatic polymer, or a vinyl aromatic polymer with a high rubber content is mixed with a vinyl aromatic polymer with a high carboxyl group content. Modified methods such as a method of mixing with an aromatic polymer can also be adopted.

The polyether used in the present invention is a polymer compound having a structural unit represented by the following formula.

(However, R is hydrogen or a methyl group, and n is an integer determined by the average molecular weight.) Ordinary polyethers have a hydroxyl group at the end of the molecular chain, but those with a methoxy structure at both ends or one end, and those with an organic Derivatives such as esters with acids can also be used. The average molecular weight of the polyether used in the present invention needs to be 20,000 or more. The average molecular weight is
If it is less than 20,000, mechanical strengths such as Izot impact strength and elongation will be reduced, and the antistatic effect will also be poor. In order to have both antistatic effect and mechanical strength, the average molecular weight should be 20,000 or more, preferably 50,000 or more.
It would be better to set it to 2 million. Specific examples of polyether include polyethylene glycol, polyethylene oxide,
Examples include, but are not limited to, polypropylene glycol, polypropylene oxide, methoxypolyethylene glycol, polyethylene glycol monolaurate, and polyethylene glycol monostearate. The amount used is preferably 4 to 20 parts by weight per 100 parts by weight of the acid-modified rubber reinforcing resin.

The alkali metal salt used in the present invention is an alkali metal salt of an alkylsulfonic acid or an alkylbenzenesulfonic acid. Specific examples include sodium octylsulfonate, lithium dodecylsulfonate, sodium dodecylsulfonate, sodium cetylsulfonate, lithium dodecylbenzenesulfonate, sodium dodecylbenzenesulfonate, sodium benzenesulfonate, and the like. In particular, alkali metal salts of dodecylbenzenesulfonic acid provide good antistatic performance.

The metal salts may be used alone or in combination of two or more.

The amount of these metal salts is preferably 0.1 to 5 parts by weight based on 100 parts by weight of the acid-modified rubber reinforcing resin.

The organic polysiloxane used in the present invention has the following structural units. Specific examples include polydimethylsiloxane, polymethylphenylsiloxane, polydiphenylsiloxane, and the like.

There is no particular limit to the viscosity, but it is 10% at 25°C.
Those having a relatively low molecular weight of ~10,000 centistokes are preferred. The amount used is 100 in total of the above (A) acid-modified rubber reinforcing resin, (B) polyether, and (C) metal salt.
A suitable amount is 0.005 to 0.1 part by weight. If it is less than 0.005 part by weight, the effect of increasing impact strength is small, and if it exceeds 0.1 part by weight, no further improvement in impact strength is observed.

The metal salts of higher fatty acids used in the present invention are C, □ to C'
It is a salt of a linear saturated monocarboxylic acid called Jt and a monovalent metal such as lithium or sodium, or a divalent metal such as zinc, magnesium, or calcium. Specific examples include sodium laurate, zinc laurate, sodium stearate, zinc stearate, magnesium stearate, calcium stearate, and the like. Preferably, the metal salt of higher fatty acid is a zinc salt. In particular, zinc stearate further improves impact strength.

Moreover, it is necessary to use it in combination with an organic polysiloxane, which results in an effect on impact strength that cannot be expected with ordinary HIPS. The appropriate amount to be used is 0.1 to 1 part by weight based on a total of 100 parts by weight of the acid-modified rubber reinforcing resin (A), the polyether (B), and the metal salt (C). If it is less than 0.1 part by weight, the effect of increasing impact strength is small, and if it exceeds 1 part by weight, no further improvement in impact strength is observed and the Vicat softening point is lowered, which is not preferable.

The method for producing the resin composition of the present invention is not particularly limited. Polyether, metal salt, acid-modified rubber reinforcing resin,
Either a method of directly mixing other additives or a method of mixing polyether and metal salt in advance and then mixing the resin and other additives are possible. As a mixing device for each component, a commonly used kneading machine such as a Banbury mixer, a roll, an extruder, etc. can be used.

Further, the resin composition of the present invention may be blended with inorganic/organic fillers such as antioxidants, light stabilizers, lubricants, coloring dyes and pigments, and other resins depending on the purpose.

〔Example〕

The present invention will be explained below based on examples. Note that the physical properties were measured according to the following procedure.

(I) Preparation of test pieces for measuring physical properties The pellets obtained in the Examples and Comparative Examples were molded into flat plates with a thickness of 178 inches and 178 inches using an injection molding machine at a cylinder temperature of 220°C. A test piece with a thickness of 74 inches was made.

(I [) Measurement of physical properties ■Surface specific resistivity: Measured under the following conditions using a flat plate with an inch thickness.

b) After molding, the condition was adjusted for 48 hours at 23° C. and 250% RH, and then measured.

After molding, the sample was immersed in running water for 10 minutes to remove surface moisture, conditioned at 23°C and 950% RH for 48 hours, and then measured.

In addition, for the measurement of (a) 2 ports), a Kyoku super insulation meter 5M-10E model manufactured by Toa Denpa Kogyo Co., Ltd. was used.

■ Half-life of charged voltage: Measured using a static honest meter (manufactured by Sagetsu Shokai) under the following measurement conditions using an 18-inch thick flat plate.

Applied voltage 8000V Application time: 1 hour Sample rotation speed: 130Orpm Measurement temperature: 23°C Measured humidity: 50%RH Note that the condition of the sample was adjusted in the same manner as for the surface specific resistivity.

■Izotsu impact strength: Based on ASTM D 256.

(Using 174 inch thick test piece) ■Tensile strength and elongation: Based on ASTM D 638.

(Using C78 inch thick test piece) ■Bending elastic modulus: Based on ASTM D790.

(Using C74 inch thick test piece) ■Vicat softening point: Based on ASTM 1525.

■Peelability: Judgment was made by bending the molded product and observing the appearance of cracks and the fractured surface.

(○=Good, ×=Peeling occurs) In addition, the numbers described below are parts by weight, and the percentages are weight percent.

(A) Production of rubber-reinforced vinyl aromatic polymer ■ Production of acid-modified rubber-reinforced polystyrene (A-1,) Polybutadiene [manufactured by Asahi Kasei Corporation, trade name 2NF35A]
) was dissolved in a mixed monomer of styrene and methacrylic acid, and acid-modified rubber-reinforced polystyrene (A-1) having a rubber content of 6% and a methacrylic acid content of 1% was obtained by bulk polymerization.

The physical properties of this polymer alone include a surface resistivity of 10+Ω or more, an isot impact strength of 7 kg-■/cIn, and a tensile strength of 370 kg/cT11. Elongation 30%, flexural modulus 26
,000kg/c1A, and the Vicat softening point was 107°C.

■Production of acid-modified rubber-reinforced polystyrene (A-2) In the production of acid-modified rubber-reinforced polystyrene (A-1), the amount of methacrylic acid is increased and polymerization is carried out to contain rubber!
Acid-modified rubber-reinforced polystyrene (A-2) with a methacrylic acid content of 6% and a methacrylic acid content of 2% was obtained. The physical properties of this polymer include a surface resistivity of 1016Ω or more and an Izot impact strength of 6Igz.
-cm/cm, tensile strength 380 kg-cm/c
m, elongation 30%, bending modulus 25,000 kg/
cIM, Vicat softening point was 110°C.

■Production of rubber-reinforced polystyrene (A-3) In the production of acid-modified rubber-reinforced polystyrene (A-1), polymerization was carried out without using methacrylic acid to obtain rubber-reinforced polystyrene (A-3) with a rubber content of 6%. Ta. The physical properties of this polymer include a surface resistivity of 1016 Ω or more, an isotropic impact strength of 8 kg-cm/cm, and a tensile strength of 380 kg/cm.
c+fl, elongation 35%, flexural modulus 26,000k
g/c and a Vicat softening point of 105"C.

(B) Polyether In the Examples and Comparative Examples of the present invention, the following polyethylene oxide or polyethylene glycol was used.

PE0-30: Polyethylene oxide with a molecular weight of 300,000.

PEG-50,000: polyethylene glycol with a molecular weight of 50,000.

Me-PEG-50,000: Polyethylene glycol with molecular weights so and ooo, with both ends methoxylated.

PEG-6,000: polyethylene glycol with a molecular weight of 7,500.

Example 1 100 parts of acid-modified rubber reinforced polystyrene (A-1), P
10 parts of RO-30 and 2 parts of sodium dodecylbenzenesulfonate were fed into a 30-cylinder twin-screw extruder and extruded at a resin temperature of 220°C to pelletize. The physical properties of the obtained composition were measured. The results are shown in Table 1.

Example 2 A composition was obtained in the same manner as in Example 1, except that sodium cetyl sulfonate was used in place of sodium dodecylbenzenesulfonate in Example 1, and its physical properties were measured.

The results are shown in Table 1.

Example 3 A composition was obtained in the same manner as in Example 1, except that lithium dodecylbenzenesulfonate was used in place of sodium dodecylbenzenesulfonate in Example 1, and its physical properties were measured. The results are shown in Table 1.

Example 4 Acid-modified rubber reinforced polystyrene in Example 1 (A-1
) A composition was obtained in the same manner as in Example 1, except that acid-modified rubber-reinforced polystyrene (A-2) was used, and its physical properties were measured. The results are shown in Table 1.

Example 5 P with a molecular weight of 50,000 was used instead of PE0-30 in Example 1.
A composition was obtained in the same manner as in Example 1, except that EG-50,000 was used, and its physical properties were measured. The results are shown in Table 1.

Example 6 In place of PEG-50,000 in Example 5, Me-
A composition was obtained in the same manner as in Example 5, except for using PEG-so and ooo, and its physical properties were measured. The results are shown in Table 1.

Example 7 A composition was obtained in the same manner as in Example 1, except that the amount of PE0-30 in Example 1 was reduced from 10 parts to 6 parts, and its physical properties were measured. The results are shown in Table 1.

Example 8 A composition was obtained in the same manner as in Example 1, except that the amount of sodium dodecylbenzenesulfonate in Example 1 was reduced from 2 parts to 1 part, and its physical properties were measured. The result is the first
Shown in the table.

Comparative Example 1 Acid-modified rubber reinforced polystyrene in Example 1 (A-1
) A composition was obtained in the same manner as in Example 1, except that rubber-reinforced polystyrene (A3) was used, and its physical properties were measured. The results are shown in Table 1.

Comparative Example 2 A composition was obtained in the same manner as in Example 1 except that polyether (B) was not used, and its physical properties were measured. The results are shown in Table 1.

Comparative Example 3 In Example 1, PE0-30 was replaced with PEG-6,000.
A composition was obtained in the same manner as in Example 1, except for replacing with , and its physical properties were measured. The results are shown in Table 1.

Comparative Example 4 The same operations as in Example 1 were performed except that sodium dodecylbenzenesulfonate was omitted, and the physical properties were measured.

The results are shown in Table 1.

Comparative Example 5 A composition was obtained in the same manner as in Example 1, except that octadodecyldimethylbenzylammonium chloride was used in place of sodium dodecylbenzenesulfonate in Example 1, and its physical properties were measured.

The results are shown in Table 1.

Comparative Example 6 A composition was obtained in the same manner as in Example 1, except that N,N-bis(2-hydroxyethyl) fatty amine was used in place of sodium dodecylbenzenesulfonate in Example 1, and its physical properties were measured. The results are shown in Table 1.

Example 9 Polydimethylsiloxane [manufactured by Toshiba Silicone ■, TSF~451] was added to 100 parts by weight of the composition produced in Example 1.
) 0.05 part by weight was blended and the same test as in Example 1 was conducted. The results are shown in Table 2.

Example 10 100 parts by weight of the composition produced in Example 1 was added with polydimethylsiloxane [manufactured by Toshiba Silicone ■].

The same test as in Example 1 was conducted by blending 0.05 parts by weight of TSF-45130.0 and 0.3 parts by weight of zinc stearate.

The results are shown in Table 2.

Margin Table 2 Resistance, 2 From the results in Parts Table 1 for 100 parts by weight of the base resin component, the following is clear. Examples 1 to 8 have low surface resistivities and are hardly changed by surface washing treatment. In other words, it exhibits excellent permanent antistatic properties. It also has excellent mechanical strengths such as Izotz impact strength and tensile properties.

That is, the resin composition of the present invention has permanent antistatic properties and has extremely excellent impact resistance.

On the other hand, when the rubber-reinforced vinyl aromatic polymer (A) is not modified with a monomer containing a carboxyl group (Comparative Example 1), a peeling phenomenon occurs. In addition, polyether (B
) (Comparative Example 2) does not have antistatic properties at all even if it contains the sulfonic acid metal salt (C). Furthermore, when the molecular weight of polyether (B) is low (Comparative Example 3), the antistatic effect is low and mechanical properties such as impact strength and tensile properties are reduced. Further, even if the polyether (B) is contained, when the metal salt (C) is not contained (Comparative Example 4), the surface resistivity is high and a practical antistatic effect cannot be obtained. Furthermore, when other salts such as a quaternary ammonium salt, which is a type of cationic surfactant, are used in place of the metal salt (C) (Comparative Example 5), N, N-bis, which is a type of nonionic surfactant, is used. When using (2-hydroxyethyl) fatty amine (Comparative Example 6)
cannot provide a permanent antistatic effect. That is, a synergistic effect is exhibited only in the combination of polyether and alkali metal salt of sulfonic acid.

Therefore, the present invention cannot achieve its intended purpose even if any of the constituent components (A) acid-modified rubber reinforcing resin, (B) polyether, and (C) metal salt is missing.

In addition, from Table 2, it is found that the composition consisting of the acid-modified rubber reinforcing resin (A), the polyether (B), and the metal salt (C) is further added with a small amount of organic polysiloxane or the metal of the organic polysiloxane and higher fatty acid. It is clear that by adding a salt, a resin composition with extremely high impact resistance can be obtained without changing physical properties such as antistatic properties and rigidity.

〔Effect of the invention〕

The resin composition of the present invention has both excellent permanent antistatic properties and mechanical properties such as impact resistance.

Patent applicant: Asahi Kasei Industries, Ltd.

Claims (1)

[Scope of Claims] 1. (A) a rubber-reinforced vinyl aromatic polymer modified with a monomer containing a carboxyl group, (B) a polyether having an average molecular weight of 20,000 or more represented by the following general formula: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, R is H or CH_3, n is an integer determined by the average molecular weight.) (C) Alkali metal salt R of alkylsulfonic acid or alkylbenzenesulfonic acid represented by the following formula -SO_3M ▲Contains mathematical formulas, chemical formulas, tables, etc.▼ (However, R is H or an alkyl group, M is Li, Na, K
It is an alkali metal such as. ) A permanently antistatic, impact-resistant resin composition comprising: 2. A permanently antistatic impact-resistant resin composition, characterized in that 0.005 to 0.1 part by weight of an organic polysiloxane is contained in 100 parts by weight of the composition according to claim 1. 3. 100 parts by weight of the composition according to claim 1 contains 0.005 to 0.1 part by weight of an organic polysiloxane and 0.1 to 1 part by weight of a metal salt of a higher fatty acid. Permanently antistatic impact resistant resin composition.