JPH1081830A - Thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a permanently antistatic thermoplastic resin excellent in transparency and properties by mixing a transparent resin having a specified refractive index with a hydrophilic polymer and a specified metal alkylnaphthalenesulfonate. SOLUTION: This composition comprises 100 pts.wt. transparent resin (A) having a refractive index of 1.47-1.54 and haze of 40 or below, 5-30 pts.wt. hydrophilic polymer (B) and 0.5-10 pts.wt. metal alkylnaphthalenesulfonate (C) and has antistatic properties not deteriorated by water washing or wiping and good transparency. It requires that the difference between the refractive index of a mixture comprising components B and C and that of component A should be 0.03 or below and that the haze should be 40 or below. Component A is exemplified by polymethyl methacrylate or an acrylonitrile styrene resin. Component B is exemplified by a polyether or a polyether ester, especially desirably a copolymer comprising naphthalenedicarboxlic acid, a sulfonate-substituted aromatic dicaboxylic acid and a polyalkylene oxide glycol.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a thermoplastic resin composition having excellent antistatic properties. More specifically, the present invention relates to a thermoplastic resin composition which is excellent in transparency and maintains an antistatic effect.

[0002]

2. Description of the Related Art Plastic materials are utilized as electric and electronic members, automobile members, medical members, household goods, and other various molded products by utilizing their excellent characteristics. By the way, plastics are generally characterized by their high electrical insulation properties, which make it difficult to dissipate the charged static electricity, adhere to dust on products, cause electric shock to workers, and malfunction of instruments and IC chips. The problem has arisen. Therefore, research on antistatic methods for various plastic materials has been conducted.

As methods for preventing static charge of plastics, there are an internal addition type and a coating type. The coating type requires a separate process, and the internal addition type is more advantageous in the production process.

In the internal addition type method, a method of kneading a ionic surfactant such as an alkyl sulfonate or an alkylbenzene sulfonate into a polymer has been generally adopted because of its excellent effect and economy. Was.

Among them, a system utilizing an alkyl (aryl) sulfonate as an ionic surfactant has been well studied. As a system having a large antistatic effect, for example, the secondary position of an alkane is substituted with a metal sulfonate. (JP-A-5-222241) and those using a phosphonium salt (JP-A-62-230835) are disclosed. However, in the method using such a low-molecular-weight surfactant, such a surfactant seeps out onto the resin surface, and although the antistatic effect is high, the effect is reduced when wiping or washing with water. There is.

On the other hand, there have been reported many methods of mixing an antistatic polymer with a resin to provide a permanent antistatic effect. Examples of such antistatic polymers include polyetheresteramides (JP-A-62-273252),
A graft polymer comprising a polyamide as a backbone polymer and a block polymer of a polyalkylene ether and a polyester as a branch polymer (JP-A-5-97984), caprolactam, a polycarboxylic acid component capable of forming an imide ring, an organic diisocyanate, and polyethylene glycol (JP-A-3-255161), a polymer comprising polyethylene ether, isocyanate and glycol (JP-A-5-222289), a polyalkylene glycol, a polyether ester comprising a glycol and a polycarboxylic acid ( JP-A-6-57153) and the like are disclosed. However, such a composition comprising two or more types of polymers usually has opaque molded articles that hardly transmit light due to scattering of light because the polymers are not microscopically mixed. Absent.

As described above, it is difficult to obtain a thermoplastic resin composition having a permanent antistatic effect without impairing the transparency of the transparent thermoplastic resin.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to have a large antistatic effect without being deteriorated by washing or wiping, etc., and to have good transparency, physical properties and moldability. It is to provide a thermoplastic resin composition.

[0009]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a hydrophilic polymer and a specific metal salt of alkylnaphthalenesulfonic acid as an ionic surfactant are used. By mixing with a transparent thermoplastic resin having a specific range of refractive index, a permanent antistatic effect is exhibited, and further, a thermoplastic resin composition excellent in transparency, physical properties and moldability can be obtained. And arrived at the present invention.

That is, according to the present invention, (A) the refractive index is 1.47 to 1.5
Transparent resin 1 in the range of 4, and the haze value is 40 or less
(B) 5 to 30 parts by weight of a hydrophilic polymer, (C) 0.5 to 10 parts by weight of a metal salt of alkylnaphthalenesulfonic acid, (A) a mixture of (B) and (C), Is a thermoplastic resin composition having excellent transparency and antistatic properties, wherein the difference between the refractive index of the thermoplastic resin is 0.03 or less and the haze value is 40 or less.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The thermoplastic resin composition of the present invention, (A) a transparent resin having a refractive index in the range of 1.47 to 1.54, and a haze value of 40 or less,
It consists essentially of (B) a hydrophilic polymer, and (C) a metal salt of alkylnaphthalenesulfonic acid.

The transparent resin (A) used in the present invention must have a refractive index in the range of 1.47 to 1.54 and a haze value of 40 or less. The transparent resin (A) is a transparent resin containing at least one unit selected from the group consisting of a methyl methacrylate unit, an acrylonitrile unit, a styrene unit, and a butadiene unit, and is therefore composed of only one type of the unit. The polymer may be a homopolymer, or may be a random polymer, a block polymer, or a graft polymer composed of only two or more kinds of the units.

The transparent resin (A) used in the present invention
Specifically, poly (methyl methacrylate), poly (acrylonitrile / styrene) resin, poly (methyl methacrylate / styrene) resin, poly (acrylonitrile / styrene / butadiene) resin, poly (methyl methacrylate / styrene / butadiene) Resins and the like can be exemplified.

In the present invention, the above transparent resin (A)
It is an essential condition that the refractive index difference of the mixture of the hydrophilic polymer (B) and the metal salt of alkylnaphthalenesulfonic acid (C) is within 0.03 in the visible light region. It is preferable that the refractive index difference be within 0.03 over the entire visible light range, but practically, it is necessary that the refractive index difference at least at the D line (wavelength 589 nm) of the Fraunhofer line be 0.03 or less. If the refractive index difference exceeds 0.03, light scattering occurs in the boundary region between the transparent resin (A) component and the hydrophilic polymer (B) component in the resin composition, and the molded product becomes turbid. The difference in refractive index is preferably small, more preferably 0.02 or less. In order to suppress the turbidity of the molded article due to such light scattering to a haze value of 40 or less, at least the refractive index difference is 0.
It must be within 03.

The above conditions can be realized in the following combination of the hydrophilic polymer (B) and the metal salt of alkylnaphthalenesulfonic acid (C).

As the hydrophilic polymer (B) in the present invention, for example, the following formulas (1) to (4)

[0017]

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And a polymer having at least one kind of polar bond selected from the group consisting of: and a polymer having a polyalkylene oxide unit in the polymer skeleton. As the polyalkylene oxide unit contained in the main chain or the side chain skeleton of the hydrophilic polymer (B), polyethylene oxide, polypropylene oxide and the like are particularly suitable.

Specific examples of the hydrophilic polymer (B) include polyether, polyamide, polyetherester, polyetheramide, polyetherurethane, polyesteramide, and polyetheresteramide.

The above-mentioned hydrophilic polymers can be used alone or as a blend of two or more kinds. In addition, random copolymers, block copolymers, graft copolymers having the above-mentioned respective resin components as segments. It can also be used in a form such as union. For example, particularly preferred polyetheresters, naphthalenedicarboxylic acid component,
Examples of the copolymer include an aromatic dicarboxylic acid component substituted with a sulfonic acid metal base, an aliphatic glycol component having 2 to 10 carbon atoms, and a poly (alkylene oxide) glycol component having a number average molecular weight of 200 to 50,000. .

The metal salt of alkylnaphthalenesulfonic acid (C) in the present invention is represented by the following formula (5)

[0022]

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[Wherein R ₁ and R ₂ are each independently
An alkyl group having 1 to 20 carbon atoms, m is an integer of 0 to 4, and n is an integer of 0 to 3. M represents an alkali metal ion or an alkaline earth metal ion. ].

The thermoplastic resin composition of the present invention has a refractive index of a mixture of (B) and (C) depending on the mixing ratio of the metal salt of alkylnaphthalene sulfonic acid (C) with the hydrophilic polymer (B). Can be controlled, and the refractive index of the mixture is made to match the refractive index of the transparent resin within 0.03 to obtain a transparent composition.

Examples of such alkylnaphthalenesulfonic acid metal salts include, for example, sodium (mono, di or tri) isopropylnaphthalenesulfonate, potassium (mono, di or tri) isopropylnaphthalenesulfonate, and (mono, di or tri) octyl. Alkali metal salts such as sodium naphthalene sulfonate, potassium (mono, di or tri) octyl naphthalene sulfonate, sodium (mono, di or tri) dodecyl naphthalene sulfonate, potassium (mono, di or tri) dodecyl naphthalene sulfonate, ( Calcium (mono, di or tri) isopropyl naphthalene sulfonate, magnesium (mono, di or tri) isopropyl naphthalene sulfonate,
Calcium (mono, di or tri) octylnaphthalenesulfonate, magnesium (mono, di or tri) octylnaphthalenesulfonate, calcium (mono, di or tri) dodecylnaphthalenesulfonate, (mono, di or tri) dodecylnaphthalenesulfonic acid Examples thereof include alkaline earth metal salts such as magnesium. In the above formula (1), when the metal ion is divalent, 1 mol of the metal ion corresponds to 2 mol of the sulfonic acid salt group.

The above-mentioned metal salts of alkylnaphthalenesulfonic acid can be used alone or in combination of two or more.

The amount of the metal salt of alkylnaphthalenesulfonic acid (C) is 0.5 parts by weight based on 100 parts by weight of (A) a transparent resin having a refractive index of 1.47 to 1.54 and (B) 5 to 30 parts by weight of a hydrophilic polymer. To 10 parts by weight, and 10 to 40 for component (B).
% By weight is preferred. If the amount is less than 0.5 parts by weight, the antistatic effect may not be sufficiently exhibited,
If the amount exceeds 10 parts by weight, the physical properties of the base transparent resin (A) may be reduced, or the handling property may be deteriorated.

The pH of the above-mentioned metal salt of alkylnaphthalenesulfonic acid is preferably from 7.0 to 9.0. When the pH of the metal salt of alkyl naphthalene sulfonic acid is 7.0 or lower or 9.0 or higher, coloring or deterioration of physical properties may be caused, or a sufficient antistatic effect may not be obtained. The pH of the metal salt of alkylnaphthalenesulfonic acid is particularly preferably from 7.5 to 8.5.

As a method for producing the above-mentioned metal salt of alkylnaphthalenesulfonic acid, there are a method in which naphthalene substituted with a metal sulfonate is alkylated by a Friedel-Crafts reaction with an alcohol, and a compound having an alkyl-substituted naphthalene skeleton. Obtained by sulfonating the compound with fuming sulfuric acid. These Friedel
The Crafts reaction and the sulfonation reaction can be easily performed by a conventionally known method.

The method for producing the thermoplastic resin composition of the present invention is not particularly limited, but (A) a transparent resin having a refractive index of 1.47 to 1.54, (B) a hydrophilic polymer,
(C) Alkyl naphthalene sulfonic acid metal salt and, as required, various additives described below can be easily mixed and melt-kneaded by a commonly used method to produce a mixture.

The order of mixing the components (A), (B), and (C) may be, for example, a method of mixing all at the same time, a method of mixing two components in advance, and then mixing the other component. And the like. Such mixing can be performed by a conventionally known method. Among these methods, all are mixed at the same time, or (B) and (C)
Is preliminarily mixed, and then (A) is preferably mixed. The latter method is more preferable in terms of antistatic effect and handling.

As a method of mixing all of them at the same time, using a uniaxial or biaxial melt extruder, (A) a transparent resin having a refractive index of 1.47 to 1.54, (B) a hydrophilic polymer,
(C) A metal salt of alkyl naphthalene sulfonic acid and, if necessary, various additives described below are added and melt-mixed.

As a method of mixing the two components in advance and then mixing with the other component, (B) and (C) were previously mixed using a single-screw or twin-screw extruder. Thereafter, the mixture is melt-mixed with (A) again using a single-screw or twin-screw extruder. If necessary, various additives described below can be added, but the mixing of the additives,
It does not matter if it is carried out at the time of either the first stage or the second stage mixing.

[0034] The thermoplastic resin composition of the present invention includes:
Various additives may be added as needed. Such various additives include glass fiber, metal fiber, aramid fiber, ceramic fiber, potassium whisker, carbon fiber, fibrous reinforcing agents such as asbestos, talc, calcium carbonate, mica, clay, titanium oxide, and aluminum oxide. , Glass flakes, milled fiber, metal flakes, various fillers such as metal powder, heat stabilizers such as phosphate esters and phosphites or catalyst deactivators, oxidation stabilizers, light stabilizers, Additives such as a lubricant, a pigment, a flame retardant, a flame retardant aid, and a plasticizer may be appropriately compounded.

The thermoplastic resin composition of the present invention comprises
The transparency is good when the haze value when formed into a molded product having a thickness of mm is 40 or less. If the haze value is higher than 40,
It is not preferable because transparency which is a characteristic of the component (A) is lost. The haze value is preferably as low as possible, and more preferably 30 or less.

[0036]

According to the present invention, the transparent resin is
By mixing the hydrophilic polymer and the metal salt of alkylnaphthalenesulfonic acid, a permanent antistatic effect can be imparted without impairing the inherent transparency of the resin. INDUSTRIAL APPLICABILITY The resin composition of the present invention is very useful for industrial materials that require transparency and a permanent antistatic effect, and the molded product is used for various applications such as OA equipment parts, building materials, and various housings. be able to.

[0037]

EXAMPLES Hereinafter, preferred embodiments of the present invention will be described with reference to Examples, but the present invention is not limited to Examples.

In the examples, "parts" means "parts by weight".
The refractive index was measured with an Abbe refractometer (manufactured by Atago Co., Ltd.). Impact strength is 1/8 inch according to ASTM D256, heat distortion temperature (HDT) is 1/8 inch according to ASTM D648, load 18.
It was measured at 6 kg / cm ² .

The measurement of the surface resistivity (R) was carried out by standing for 24 hours in an atmosphere of 20 ° C. and a humidity of 60%, and then applying an applied voltage using a super insulation meter (SM-8210 manufactured by Toa Denpa Kogyo Co., Ltd.). 1000V
Was measured. The molded article was washed with running water of 30 ° C. for 2 hours, and the moisture was wiped off with clean paper. Thereafter, drying was performed under the same conditions, and the measurement of the surface resistivity was performed.

Regarding the light transmission of the molded product, ASTM D100
According to 3, the light transmittance was measured. A spectrophotometer (UV-2400PC manufactured by Shimadzu Corporation) was used for the measurement, and the sample thickness was 2 mm.
And measured by CIE Source C.

REFERENCE EXAMPLE 1 Polyetheramide (refractive index: 1.490) mainly composed of 6 units of nylon and polyethylene oxide unit, and sodium isopropylnaphthalenesulfonate (hereinafter referred to as INS-Na) or sodium dodecylbenzenesulfonate ( (Hereinafter referred to as DBS-Na) was melt-kneaded and pelletized with the composition shown in Table 1 to obtain a master batch. Melt kneading is performed using a 30 mm φ co-rotating twin-screw extruder (PCM3 manufactured by Ikegai Iron Works Co., Ltd.
0) using a cylinder temperature of 200 ° C. and an average residence time of about 5 minutes. Table 1 also shows the refractive index of each master batch.

[0042]

[Table 1]

[Examples 1 to 3] The master batch No. 1 or No. 2 prepared in Reference Example 1 and a transparent poly (methyl methacrylate / styrene / butadiene) -based resin (refractive index)
1.520) was melt-kneaded with the composition shown in Table 2. Melt kneading was carried out using a 30 mmφ co-rotating twin-screw extruder (PCM30 manufactured by Ikegai Iron Works Co., Ltd.) at a cylinder temperature of 220 ° C. and an average residence time of about 5 minutes. Next, using an injection molding machine (M-50B, manufactured by Meiki Seisakusho Co., Ltd.), injection molding was performed at a cylinder temperature of 220 ° C. to obtain a molded product having a thickness of 2 mm, and the surface resistivity was measured. Table 2 shows the results together with the mechanical properties. The measurement result of the surface specific resistivity (R) was represented by a common logarithm (log R).

Comparative Example 1 Transparent MBS resin (refractive index 1.520)
Was subjected to injection molding at a cylinder temperature of 220 ° C. using an injection molding machine (M-50B manufactured by Meiki Seisakusho Co., Ltd.), and 2 m
A molded product having a thickness of m was obtained, and the surface resistivity was measured. Table 2 shows the results together with the mechanical properties.

[Comparative Examples 2 and 3] The master batch No. 3 prepared in Reference Example 1 and the transparent MBS resin (refractive index 1.520) were prepared by using the same apparatus and method as in Examples 1 to 3. 2 was obtained by melt-kneading and injection molding with the composition shown in FIG.
The surface specific resistivity of the molded product having a thickness of mm was measured.
Table 2 shows the results together with the mechanical properties.

[0046]

[Table 2]

Claims (3)

[Claims] (A) 100 parts by weight of a transparent resin having a refractive index in the range of 1.47 to 1.54 and a haze value of 40 or less;
(B) 5 to 30 parts by weight of a hydrophilic polymer, (C) 0.5 to 10 parts by weight of a metal salt of alkyl naphthalene sulfonic acid, and a refractive index of a mixture of (B) and (C) and (A) A thermoplastic resin composition having excellent transparency and antistatic properties, wherein the difference is 0.03 or less and the haze value is 40 or less. 2. The transparent resin (A) is composed of polymethyl methacrylate, poly (acrylonitrile / styrene) resin, poly (methyl methacrylate / styrene) resin, poly (acrylonitrile / styrene / butadiene) resin and poly (methyl methacrylate / The thermoplastic resin composition according to claim 1, which is at least one resin selected from the group consisting of (styrene / butadiene) resin. 3. The method according to claim 1, wherein the hydrophilic polymer (B) is a polyether,
The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin composition is at least one polymer selected from the group consisting of polyamide, polyetherester, polyetheramide, polyetherurethane, polyesteramide, and polyetheresteramide.