JP3006224B2 - Resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antistatic resin composition for injection molding having excellent permanent antistatic properties and an improved surface appearance of a molded product.

[0002]

2. Description of the Related Art ABS graft copolymers have been used in a wide range of fields because of their excellent mechanical properties.
Application to equipment and various dustproof fields is limited. ABS
As a method of imparting antistatic properties to the graft copolymer,
Although there are methods such as applying a surfactant or the like to the surface of the resin or kneading it into the resin, there is a problem in the durability of the antistatic effect. The durability deteriorates especially when washing with water.

[0003] In order to improve this point, a method of mixing an epihalohydrin copolymer (JP-A-61-18)
5557, JP-A-62-25164, JP-A-62-264.
No. 273247) and a method of mixing other ethylene oxide copolymers (Japanese Patent Application Laid-Open No. 64-26674), a method of adding an acrylate polymer as a third component (Japanese Patent Application Laid-Open No. 64-1748), and the like. Method of adding a modified vinyl polymer (JP-A-2-269147)
Has been proposed. However, it has been pointed out that while these methods improve the permanent antistatic property, the surface of a product obtained by injection molding has poor appearance such as weld lines and pearl gloss. .
This impairs the commercial value of ABS resin, which is often used in fields requiring aesthetic appearance, such as OA equipment, housing for home electric appliances and interior materials, and is often manufactured by injection molding, and limits its use. It leads to things.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide an antistatic resin composition for injection molding based on an ABS resin, which gives an excellent surface appearance.

[0005]

Means for Solving the Problems In order to solve the above problems, the present inventors have conducted intensive studies and as a result, have found that 5
0% or more of ethylene oxide and a refractive index (n _D
^The present inventors have found that the above object can be sufficiently achieved by blending an ethylene oxide copolymer having ²⁰ ) of 1.50 or more with an ABS resin, and have reached the present invention. That is, in the present invention, the weight ratio of the acrylonitrile compound (A) monomer component to the vinyl aromatic compound is 10:
ABS graft copolymer 10 having a ratio of 90 to 50:50
50% by weight as a monomer component (B) based on 0 parts by weight
Containing the above ethylene oxide and having a refractive index (n _D ²⁰ )
Is an ethylene oxide copolymer having a molecular weight of 1.50 or more
An object of the present invention is to provide an antistatic resin composition for injection molding excellent in surface appearance of a molded product, characterized by containing 0 parts by weight.

The ABS graft copolymer used in the present invention comprises at least 40% by weight of a combination of a vinyl aromatic compound and an acrylonitrile compound and 60% by weight or less of a rubber base material. The term "ABS" refers to a copolymer that is primarily composed of acrylonitrile, butadiene, and styrene, but in recent years this definition has been expanded to include all or some of these components as analogs. Is a copolymer substituted with a compound having a large size, which essentially exhibits the characteristics of a so-called ABS resin with respect to basic properties such as moldability, rigidity, impact resistance, glossiness and heat resistance. Is also used.
Vinyl aromatic compounds usable in the present invention include vinyl anilines, vinyl aromatic compounds such as styrene and α-methylstyrene, halogenated styrenes such as chlorostyrene and dibromostyrene, and alkylstyrenes such as vinyltoluene. And various copolymerizable vinyl aromatic compounds. Mixtures of different vinyl aromatic compounds can also be used. However, preference is given to styrene, halogenated styrenes, α-methylstyrenes, alkylstyrenes or mixtures thereof. In a most preferred embodiment, the graft copolymer contains at least some styrene.

Acrylonitrile compounds usable in the present invention include acrylonitrile, halogenated acrylonitrile,
Methacrylonitrile, ethacrylonitrile, and further alkyl acrylonitrile derivatives or derivatives thereof.
Other non-nitrile acryloyl compounds such as methyl methacrylate, ethacrylate and acrolein are AB
20% by weight or less, preferably 1% by weight in the S-graft copolymer
It may be present in relatively small amounts up to 0% by weight. A preferred compound is acrylonitrile and / or methacrylonitrile. Furthermore, the most preferred ABS graft copolymer contains acrylonitrile as the main acrylo compound,
It contains a small amount of methacrylonitrile. In the ABS graft copolymer used in the present invention, the weight ratio of the acrylonitrile-based compound as the monomer component to the vinyl aromatic-based compound needs to be in the range of 10:90 to 50:50. When the weight ratio of the acrylonitrile-based compound is less than this range, it is difficult to obtain an excellent surface appearance of an injection-molded product, which is one of the objects of the present invention. On the other hand, it is well known in the art that if the ratio exceeds this range, the fluidity and thermal stability during molding of the ABS graft copolymer itself decrease, which is not preferable.

As the rubber substrate, any of various known rubber substrates can be used. However, a preferred rubbery substrate is made of a diene rubber. Particularly preferred rubber materials are polybutadiene rubber and butadiene copolymer rubber, for example, containing 35% or less of a copolymerizable monomer such as acrylonitrile, alkyl acrylate, alkyl methacrylate or a vinyl aromatic monomer such as styrene. Butadiene copolymer. Further, although not as preferable as the diene rubber, other rubber base materials can be used. Examples include acrylic rubber or ethylene derived from alkyl acrylate homopolymers or copolymers.
Propylene non-conjugated diene copolymer rubber, semi-crystalline or
Amorphous chlorinated polyethylene and the like can be mentioned.

[0009] The graft copolymer of the present invention may contain small amounts of various known additives during the polymerization in order to improve the properties of the resin. Examples of such additives include crosslinkable monomers such as divinylbenzene and ethylene glycol dimethacrylate. Many of the above graft copolymers used in the present invention are commercially available in a wide range, or can be produced by various known graft polymerization techniques. One of the methods is a method in which an acrylonitrile monomer and a vinyl aromatic monomer are copolymerized with a rubber base material that has been formed in advance. U.S. Pat. No. 3,238,2
No. 75 describes a representative method for producing a traditional ABS graft copolymer from styrene and acrylonitrile. Further, the same specification discloses a graft copolymer having a high rubber base material content and a preformed rigidity such as styrene-acrylonitrile copolymer (SAN), acrylonitrile-α-methylstyrene, and styrene copolymer. And a method of producing an ABS resin by blending with a copolymer of the formula (1).

[0010] The proportions of the vinyl aromatic compound, acrylonitrile compound and rubbery substrate depend in part on the desired properties of the thermoplastic resin. However, from the viewpoint of maintaining the balance of properties such as moldability, rigidity, impact resistance, glossiness, and heat resistance, at least 40% by weight of the ABS graft copolymer is used.
Of a vinyl aromatic compound and an acrylonitrile compound, and the rubber base material is preferably 60% by weight or less. More preferably, the combination of the vinyl aromatic compound and the acrylonitrile compound in the ABS graft copolymer is at least 50% by weight and the rubber base material is 50% by weight or less. A polymer blend in which a part of the ABS graft copolymer is replaced by another polymer can also be used as long as the properties of the ABS graft copolymer are imparted. Preferred blends include, for example, blends with vinyl chloride polymer, styrene polymer, impact-resistant styrene polymer, methyl methacrylate polymer, polyurethane, polycarbonate, polyamide, polyester such as polybutylene terephthalate, polyphenylene ether, polyglutarimide, chlorinated polyethylene and the like. be able to. ABS in the blend
The content of the graft copolymer is usually at least 30% by weight or more, preferably 50% by weight or more.

In the ethylene oxide copolymer used in the present invention, 50% of ethylene oxide is contained as a monomer component.
A resin composition having excellent antistatic properties can be obtained by being contained in an amount of not less than% by weight. Further, the copolymer is copolymerized with another specific monomer so that the refractive index (n _D ²⁰ ) of the copolymer is 1.5.
By setting it to 0 or more, the surface appearance of a product obtained by injection molding the resin composition is remarkably improved. The term “defective surface appearance of the product” as used herein refers to a so-called pearl luster and a weld line, that is, a linear mark generated by merging of resin compositions in a mold during injection molding. The ABS resin contains an aromatic compound as a main monomer and therefore has a relatively high refractive index, and is about 1.55 or more, depending on its copolymer composition. When an ABS resin and another polymer are mixed and used, it is well known that a resin composition having high transparency is obtained by approximating the refractive indices of both as much as possible. However, a weld line may also occur when, for example, a resin composition containing a single resin is injection-molded, and a composition containing a mixture of an ABS resin and an ethylene oxide copolymer like the composition of the present invention. In this case, it is completely unexpected that the appearance defect due to the weld line is improved by approximating the refractive indices of the two.

The monomer component constituting the ethylene oxide copolymer used in the present invention is, in addition to ethylene oxide, a monomer having a refractive index (n _D ²⁰ ) of 1.54 or more, preferably 1.55 or more. Selected from things. Such a monomer is selected from compounds represented by the following general formula.

[0013]

Embedded image

However, in the general formula, Ar is at least
One halogen atom, and / or an aryl group, and / or
It represents a single ring carbon aromatic group or heterocyclic aromatic group, or may have a substituent group fused carbon-based aromatic group or heterocyclic aromatic group substituted with aralkyl radical, n Is an integer of 0 or 1, X is O (oxygen), S (sulfur) or-
Represents an O-CO- group. To illustrate this specifically, 2
Phenyl groups such as -chlorophenyl glycidyl ether, 4-chlorophenyl glycidyl ether, 2,4,6-trichlorophenyl glycidyl ether, 2,4-dibromophenyl glycidyl ether, and 2,4-dibromocresyl glycidyl ether are substituted with halogen atoms Phenyl glycidyl ethers, 2-phenylphenyl glycidyl ether, 4-phenylphenyl glycidyl ether, 4-benzylphenyl glycidyl ether
Phenyl glycidyl ethers in which a phenyl group such as phenyl , 4-cumylphenyl glycidyl ether is further substituted with a substituent containing an aromatic group, 1-naphthyl glycidyl ether, 2-naphthyl glycidyl ether, 9-phenanthryl glycidyl Aryl glycidyl ethers in which an aryl group such as an ether is a condensed aromatic group,

4-chloro-1-naphthyl glycidyl ether, 2,4-dichloro-1-naphthyl glycidyl ether, 1-bromo-2-naphthyl glycidyl ether,
2-bromo-2-naphthyl glycidyl ether, 1,6
Aryl glycidyl ethers such as -dibromo-2-naphthyl glycidyl ether, which are condensed aromatic groups in which aryl groups are substituted with halogen atoms, phenyl glycidyl thioethers such as 4-chlorophenyl glycidyl thioether, 2-chlorophenyl glycidyl thioether; Styrene oxides in which a phenyl group is substituted with a halogen atom, such as 4-chlorostyrene oxide, 2-chlorostyrene oxide, 2,6-dichlorostyrene oxide, and 4-bromostyrene oxide, 2-vinylnaphthalene oxide, 9-vinyl Epoxides of condensed aromatic compounds substituted with a vinyl group such as phenanthrene oxide, 4- (2,3-epoxypropoxy) indole
Gurishijiruete of such condensation was heterocyclic aromatic compounds
Le ethers, glycidyl-2-chlorobenzoate, glycidyl-3-chlorobenzoate, glycidyl-2,4-dichloro-benzoate, glycidyl-2,5-dichloro-benzoate, glycidyl-2-bromobenzoate, as glycidyl-4-bromobenzoate Glycidyl esters of benzoic acid substituted with various halogen atoms, and glycidyl esters of condensed aromatic carboxylic acids such as glycidyl-1-naphthoate and glycidyl-2-naphthoate. In addition to the above general formula, glycidyl carbazo
, Glycidyl indole, glycidyl phenothiazi
Fused heterocyclic systems substituted with glycidyl groups such as
Aromatic compounds also make up the ethylene oxide copolymer
It can be used as a monomer component.

In addition to ethylene oxide and the above monomers, other monomers may be used as long as the ethylene oxide component is 50% by weight or more and the refractive index (n _D ²⁰ ) of the obtained copolymer is 1.50 or more. A monomer can also be used in combination as a copolymer component. Such other monomer components include alkylene oxides such as propylene oxide and 1-butene oxide, cycloalkyl epoxides such as cyclohexene oxide and vinylcyclohexene monoxide,
Aromatic-substituted epoxides such as styrene oxide and α-methylstyrene oxide, halogen-substituted alkylene oxides such as epichlorohydrin and epibromohydrin, ethyl glycidyl ether, butyl glycidyl ether,
Alkyl glycidyl ethers such as chloroethyl glycidyl ether, alkenyl glycidyl ethers such as allyl glycidyl ether, aromatic glycidyl ethers such as phenyl glycidyl ether, glycidyl acetate, glycidyl propionate, glycidyl methacrylate, glycidyl benzoate Esters and the like. The ethylene oxide copolymer used in the present invention is 50
% By weight or more of ethylene oxide, and the refractive index of the monomer is 1.
It is obtained by ring-opening polymerization in combination with an epoxide monomer of 54 or more, preferably 1.55 or more, and if necessary, another epoxide monomer.

The molecular weight of the ethylene oxide copolymer is 0.1.
Using a 1 g / d1 monochlorobenzene solution, the reduced viscosity measured at 80 ° C. is in the range of 0.5 to 10, preferably 1 to 5. If the ratio is below this range, the mechanical properties of the composition of the present invention decrease, while if it exceeds this range, molding processability, especially molding fluidity, is unfavorably reduced. The polymerization catalyst is a known dialkyl zinc-water, trialkyl aluminum-water-
Any of acetylacetone, a thermal condensate of an organic tin and a phosphoric ester, and the like can be used.

The solvent for the copolymerization reaction includes butane, pentane, hexane, heptane, benzene, toluene, chlorobenzene and the like. Alternatively, the reaction can be performed without a solvent, if necessary. The reaction temperature is desirably in the range of 0 to 60 ° C. The copolymer may be any of a block copolymer, a graft copolymer, a random copolymer or an alternating copolymer, but is preferably a random copolymer in order to obtain excellent antistatic properties. desirable.

The object of the present invention is achieved when the ethylene oxide copolymer used in the present invention is contained in an amount of 5 to 30 parts by weight based on 100 parts by weight of the ABS graft copolymer. Below this range, it is difficult to obtain the antistatic property, which is one object of the present invention. On the other hand, above this range, the mechanical properties inherent in the ABS resin are undesirably reduced. Also, these ethylene oxide copolymers,
It can be used in combination with an ethylene oxide homopolymer or another ethylene oxide copolymer as long as the properties of the resin composition of the present invention can be imparted. Suitably, the copolymer of the present invention is contained in an amount of at least 30% by weight, preferably 50% by weight or more, based on the total amount of the ethylene oxide homopolymer and the copolymer.

The antistatic resin composition of the present invention is prepared by mixing the ABS graft copolymer and ethylene oxide copolymer by any of various known techniques such as mixing in a Banbury mixer, melt mixing, extrusion and milling. Obtained by mixing. Ethylene oxide copolymer and ABS used in the present invention
A part of the graft copolymer is a component as disclosed in JP-A-2-269147, that is, at least one selected from a carboxyl group, an epoxy group, an amino group, a hydroxyl group, a polyalkylene oxide group or a derivative thereof. Can be replaced by blending with a modified vinyl polymer having a functional group of (1) as long as the properties of the ABS graft copolymer are imparted. The suitable range depends on the properties of the modified vinyl polymer selected, but the ABS graft copolymer is usually at least 30% by weight, preferably 50% by weight or more.

Further, a small amount of a crosslinking agent such as dicumyl peroxide may be included. However, a crosslinking agent is not always necessary to obtain a suitable composition. Other known additives such as impact modifiers, lubricants, stabilizers, fillers, antioxidants,
An ultraviolet absorber and a flame retardant can be added. Also, other known antistatic agents, such as long-chain amines, ethers and esters, amides, quaternary ammonium salts and sulfonic acids and alkyl, aryl or alkylaryl sulfonates and phosphoric acid, alkyl, aryl or aralkyl phosphates, especially These ethoxylate derivatives and low molecular weight polyether glycols can be added. The additive is ethylene oxide copolymer and / or AB
It may be separately added to the S-graft copolymer, or may be added during or after mixing the ethylene oxide copolymer and the resin component.

[0022]

The present invention will be described in detail below with reference to examples. Reference Example 1 a) Preparation of Polymerization Catalyst Dibutyltin oxide was placed in an 11-neck four-necked flask equipped with a stirrer, a nitrogen inlet tube, a low boiling point discharge tube, and a thermometer.
After 6 g and 80.3 g of tributyl phosphate were charged and the inside of the vessel was replaced with nitrogen, the mixture was heated with stirring at 250 ° C. for 20 minutes, and the obtained solid was used as a polymerization catalyst. b) Production of ethylene oxide copolymer 2 equipped with a stirrer, nitrogen introduction tube, thermometer and sample introduction tube
Hexane 420 in a nitrogen atmosphere in a stainless steel reactor 01
0 g, 823 g of ethylene oxide, 282 g of 1-naphthyl glycidyl ether and 15 g of the catalyst prepared above are added and reacted at 20 ° C. for 8 hours with stirring. 5m water after reaction
l and 5.5 g of 4,4'-thiobis (3-methyl-6-tert-butylphenol) as an antioxidant are added and stirred at room temperature for 15 minutes. Then the polymer is filtered off,
After washing with hexane, the resultant was dried at 50 ° C. for a whole day and night to obtain a copolymer (1060 g). According to the NMR method, the composition of the obtained copolymer was ethylene oxide: 1-naphthyl glycidyl ether = 75: 25 (weight ratio). The refractive index (n _D ²⁰ ) of this polymer was 1.508. Again before
The reduced viscosity of this polymer was measured by the method described above.
4.0. Reference Examples 2 to 7 Tables 1 and 2 show the results of producing an ethylene oxide copolymer in the same manner as in Reference Example 1.

[0023]

[Table 1]

[0024]

[Table 2]

Examples 1 and 2 Comparative Examples 1 and 2 An ABS graft copolymer (I) comprising 30% by weight of an acrylonitrile component, 55% by weight of a styrene component and 15% by weight of a butadiene component was obtained by a known emulsion polymerization method and a known graft polymerization method. ) Manufactured. 100 parts by weight of the copolymer (I) was mixed with 0.5 parts of ethylenebisstearylamide as a lubricant.
Parts by weight, 0.5 parts by weight of phthalocyanine blue as a pigment, 10 or 20 parts by weight of the ethylene oxide copolymer prepared in Reference Example 1, and 20 parts by weight of the copolymer prepared in Reference Example 4. Were pelletized and injection molded according to the following methods, and the surface appearance and physical properties of the obtained molded product are shown in Table 3. Pelletization: Each mixture was kneaded with a 1.7 liter Banbury mixer, formed into a sheet with two rolls having a surface temperature of 170 ° C., cooled, and then pelletized into about 4 mm square with a pelletizer. Injection molding: The obtained pellet was dried with a tray dryer at 90 ° C. for 4 hours and then subjected to injection molding. The molding machine used was Allrounder A170H (90-200) manufactured by Ahburg. The molding conditions are as follows. Screw diameter: 22Mmfai Mold temperature: 60 ° C. cylinder temperature: 220 ° C. mold clamping force 18 ton injection pressure: 2,000 Kg / cm ² Cooling time: 10 sec injection time: 0.5 seconds holding pressure: between 1500 Kg / cm ² dwell time : 7 seconds

Outline of mold: 81 mm x 87 mm x 2 m thick
m with a flat cavity and a runner (4 mm inner diameter)
φ) branches into two, and the cavity is filled with resin from two gates. It is designed so that a weld line is generated almost at the center of the flat plate. Gateland 2m
m, width 2 mm, thickness 1 mm, gate interval 51 mm. The plane and cross section of a test piece injection molded using this mold are shown in FIGS. 1 and 2, respectively. Surface appearance Weld line and pearl luster were visually determined, and the results were indicated by symbols. Physical properties Antistatic Charging voltage half-life (seconds): Measured by Honestometer (manufactured by Shisido Electrostatic Co., Ltd.). Applied voltage 10KV. Surface resistivity measurement (Ω): according to JIS K6911. Test conditions 23 ° C, 50% RH Mechanical properties Yield point stress (Kg / cm ² ) ASTM D-63
8,50 mm / min Elongation at break (%) ASTM D-63
8,50 mm / min Izod impact strength (Kg · cm / cm) ASTM D
-256-56A (with 1/2 inch notch) Flexural modulus (Kg / cm ² ) ASTM D-790

[0027]

[Table 3]

Examples 3 and 4 Comparative Examples 3 to 6 The ABS graft copolymer (I) used in Example 1 and the ABS graft copolymer (II) produced by a separately known emulsion polymerization method (acrylonitrile 5% by weight) , Butadiene 15
% Of styrene and 80% by weight of styrene)
A mixture of 0.5 parts by weight of ethylenebisstearylamide as a lubricant and phthalocyanine blue as a pigment , and the copolymers prepared in Reference Examples 1 , 2 , 5 , 6 and 7 were added to 00 parts by weight. Example 1
Table 4 shows the results of molding and testing in the same manner as described above.

[0029]

[Table 4]

Examples 5 and 6 Comparative Examples 7 to 9 90 parts by weight of the same ABS graft copolymer (I) used in Example 1 and polyvinyl chloride 10 having a polymerization degree of 800
Ethylene bisstearylamide as a lubricant in parts by weight
5 parts by weight, 0.5 part by weight of phthalocyanine blue as a pigment, 0.5 part by weight of dibutyltin maleate as a stabilizer, and a copolymer prepared in Reference Example 3 were molded and tested in the same manner as in Example 1. The results are shown in Table 5.

[0031]

[Table 5]

[0032]

Industrial Applicability The resin composition of the present invention has excellent permanent antistatic properties, has a remarkably improved surface appearance, and is of great industrial value.

[0033]

[Brief description of the drawings]

FIG. 1 is a plan view of a test piece obtained by injection molding for a test of the present invention.

FIG. 2 is a sectional view taken along the line AA in FIG.

[Description of Signs] 1 Indicates a sprue (root diameter 5 mmφ) orthogonal to the runner.

──────────────────────────────────────────────────続 き Continued on front page Examiner Yasue Uchida (58) Field surveyed (Int. Cl. ⁷ , DB name) C08L 55/02 C08L 71/02

Claims (1)

(57) [Claims] 1. A weight ratio of an acrylonitrile compound as a monomer component to a vinyl aromatic compound is 10:
ABS graft copolymer 10 having a ratio of 90 to 50:50
50% by weight as a monomer component (B) based on 0 parts by weight
Containing the above ethylene oxide and having a refractive index (n _D ²⁰ )
Is an ethylene oxide copolymer having a molecular weight of 1.50 or more
An antistatic resin composition for injection molding having excellent surface appearance of a molded product, characterized by containing 0 parts by weight.