JPH07216178A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To provide a thermoplastic composition having a high antistatic effect and its persisency, giving a molding without surface stickiness and showing the properties inherent in the resins. CONSTITUTION:This resin composition is the one comprising 75-99wt.% thermoplastic resin selected from a polyamide resin, a methacrylic resin and a styrene polymer and 1-25wt.% potassium ionomer of an ethylene/(meth)acrylic acid random copolymer having a potassium ion concentration of 1.5mol/kg of the ionomer or above or the one comprising the above two components and at most 20wt.%, based on the ionomer, polyoxyalkylene polyol which is liquid at 25 deg.C.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a thermoplastic resin composition having excellent antistatic properties.

[0002]

2. Description of the Related Art Thermoplastic resins such as polyamide, polyester, ABS resin, polystyrene, methacrylic resin, and polyolefin are widely used in packaging materials, general industrial materials such as automobile parts and home electric appliance parts. Resins generally have a large electric resistance, are easily charged by friction, and have serious drawbacks such as powdery contents adhering and dust absorption.

Therefore, various antistatic agents have been blended with thermoplastic resins. For example, as such a kneading type antistatic agent, glycerin fatty acid ester,
Sorbitan fatty acid ester, etc. are used,
It is difficult to maintain that effect for a long time. If a large amount of antistatic agent is added, the sustainability of the effect can be increased, but undesirable phenomena such as dusting and whitening may occur on the surface of the molded product, and tackiness may occur on the surface, causing dust to adhere. It is not a generally accepted method because it becomes easier and reduces the product value.

In order to solve the drawbacks of the kneading-type antistatic agent, grafting of polymethylmethacrylate (JP-A-1-170603) in which 20 to 30 mol% of methoxy groups are modified with diethanolamine, and alkoxypolyethyleneglycolmethacrylate are grafted. Copolymer (Japanese Patent Publication Sho 5)
No. 8-39860), imide-modified styrene-maleic anhydride copolymer, and then quaternized cationized polymer (Japanese Patent Publication No. 29820/1989), terminal carboxyl of polymethylmethacrylate having a carboxyl group at the terminal. Comb type copolymer of high molecular weight monomer whose group is converted to methacryloyl group with glycidyl methacrylate and aminoalkyl acrylate or acrylamide and its quaternized cation-modified product (JP-A-62-1217).
No. 17), ethylene acrylamide copolymer 4
Graded cation-modified product (JP-A-4-198107)
Polymer compounds having an antistatic functional group such as are proposed.

However, any of the above polymer compounds may impair the original properties of the resin. Insufficient antistatic property. It is disadvantageous in terms of cost. Poor thermal stability. It has an unpleasant odor. There was a problem.

[0006]

DISCLOSURE OF THE INVENTION The present inventors, after recognizing the above technical problems, have made earnest studies to find a thermoplastic resin excellent in semipermanent antistatic property. As a result, a polyamide-based resin, a methacrylic resin, and a styrene-based polymer such as an ABS resin or polystyrene can be used as a resin composition having an excellent antistatic effect and excellent durability while maintaining its excellent properties. I came to find out the prescription. Therefore, an object of the present invention is to provide a thermoplastic resin composition having an antistatic property that can be used in various molding applications.

[0007]

According to the present invention, a thermoplastic resin selected from polyamide resins, methacrylic resins, and styrene polymers is contained in an amount of 75 to 99% by weight and a potassium ion concentration of 1.5 mol / kg. Provided is a thermoplastic resin composition comprising 1 to 25% by weight of a potassium ionomer of an ethylene / (meth) acrylic acid random copolymer which is an ionomer or more. Here, (meth) acrylic acid means acrylic acid or methacrylic acid.

The present invention also includes a composition in which 20% by weight or less of the ionomer and a polyoxyalkylene polyol which is liquid at 25 ° C. are blended.

In the present invention, examples of the polyamide resin include nylon 6, nylon 66, nylon 12, polyamide elastomer, terephthalic acid / isophthalic acid / hexamethylenediamine copolyamide, etc. as typical examples.

The methacrylic resin which can be used in the present invention is produced by a suspension polymerization method, a continuous bulk polymerization method, a continuous solution polymerization method or the like, and a methyl methacrylate monomer and an acrylic acid such as methyl acrylate or ethyl acrylate. This is a generic term for methacrylic resins obtained by copolymerizing 0.5 to 15% by weight of ester.

The styrene polymer which can be used in the present invention is a homopolymer or copolymer of styrene, and ABS resin and polystyrene can be exemplified as typical examples thereof. Here, the ABS resin is a generic term for rubber-reinforced styrene polymers synthesized by various manufacturing methods such as a blending method, a grafting method, or a graft-blending method, and includes polybutadiene, styrene-butadiene rubber, ethylene. Representative examples include those obtained by graft-polymerizing styrene and other monomers such as acrylonitrile, methyl methacrylate, α-methylstyrene and ethylene bismaleimide to a rubber component such as propylene / diene rubber.

Further, polystyrene is not only general-purpose polystyrene synthesized by a production method such as suspension polymerization method or continuous polymerization method, but also impact-resistant polystyrene obtained by graft-polymerizing styrene to a rubber component such as butadiene rubber. Etc. are collectively referred to.

These polyamide resins, methacrylic resins and styrene polymers may be used alone or in admixture of two or more.

When a potassium ionomer is blended with a polymer other than the polyamide resin, the methacrylic resin, and the styrene polymer, such as polyester or polyolefin, unless the potassium ionomer is used in a relatively large amount, A composition having the antistatic property of 1 cannot be obtained.

In the present invention, a thermoplastic resin selected from such polyamide resins, methacrylic resins, and styrene polymers has a potassium ion concentration of 1.5 mol / kg ionomer or more, preferably 1.8 to. 3.0
A potassium / ionomer of ethylene / (meth) acrylic acid random copolymer, which is a mol / kg ionomer, is blended. Even if a potassium ionomer having a potassium ion concentration of less than 1.5 mol / kg ionomer is blended, no significant improvement in antistatic property is observed.

As the above-mentioned potassium ionomer, a potassium ionomer of ethylene / acrylic acid random copolymer is particularly preferable.

Further, a polyoxyalkylene polyol which is liquid at 25 ° C. can be added to the above composition in an amount of 20% by weight or less based on the ionomer. By adding the polyoxyalkylene polyol, an antistatic effect can be obtained. Is further improved.

The polyoxyalkylene polyol used in the present invention is liquid at 25 ° C. Solid substances are not preferable because no significant improvement in non-chargeability is observed. On the other hand, if the molecular weight is too low, the number average molecular weight is usually 2 because it tends to bleed.
It is preferable to use the one of 00 to 800, especially 300 to 700. Specific examples of polyoxyalkylene polyols include polyoxyethylene glycol and polyoxyethyleneoxypropylene glycol,
Most preferred is the use of polyoxyethylene glycol.

The amount of polyoxyalkylene polyol compounded is 20% by weight or less, preferably 10% by weight, based on the ionomer.
It is less than or equal to weight%. The polyoxyalkylene polyol may be mixed separately with each of the components of the ionomer and the thermoplastic resin, but it is also possible to mix the polyoxyalkylene polyol with the ionomer in advance and prepare the polyoxyalkylene polyol-containing ionomer with the thermoplastic resin.

The ethylene / (meth) acrylic acid random copolymer used as the raw material of the above potassium ionomer contains other unsaturated monomer components such as methyl (meth) acrylate, ethyl (meth) acrylate, (meth). ) Acrylic acid esters and methacrylic acid esters such as isobutyl acrylate and n-butyl (meth) acrylate, or unsaturated esters such as vinyl acetate may be copolymerized.

Such copolymers generally contain 60 to 90% by weight of ethylene, especially 70 to 88% by weight, (meth).
Acrylic acid is preferably copolymerized at 10 to 40% by weight, particularly 12 to 30% by weight, and other unsaturated monomer components are copolymerized at a rate of 0 to 30% by weight, particularly 0 to 20% by weight. Such a copolymer can be obtained by randomly copolymerizing each polymerization component under high temperature and high pressure.

A thermoplastic resin selected from a polyamide resin, an acrylic resin, and a styrene polymer, and ethylene.
The mixing ratio of the potassium ionomer of the (meth) acrylic acid random copolymer is 75 to 99% by weight of the former, preferably 80 to 96% by weight, and 1 to 25% by weight of the latter, preferably 4 to 20% by weight. . When the amount of the ionomer component is less than the above range, the antistatic effect is small. On the other hand, when the amount of the ionomer component is more than the above range, the properties originally possessed by the polyamide resin, the acrylic resin and the styrene polymer are impaired, and the foaming phenomenon due to the increase in hygroscopicity is likely to appear. When no other antistatic agent is used in combination, the amount of potassium ionomer added is 0.075 per 1 kg of the composition.
It is preferable to mix it in a proportion of at least mol, particularly at least 0.10 mol.

Various additives may be added to the thermoplastic resin composition of the present invention depending on the purpose of use. Examples of such additives include other antistatic agents, antioxidants, light stabilizers, ultraviolet absorbers, nucleating agents, pigments, dyes, antifog agents, heat retaining agents, lubricants, inorganic fillers, foaming agents, crosslinking agents. Examples thereof include agents. The thermoplastic resin composition of the present invention may also contain other thermoplastic resins in a small amount. The potassium ionomer used in the present invention has good compatibility with polyamide-based resins, methacrylic resins, and styrene-based polymers, but a compatibilizing agent can be used to further assist the compatibility. As the compatibilizer, ethylene copolymers such as ethylene / acrylic acid ester / carbon monoxide copolymer are effective.

The thermoplastic resin composition of the present invention can be prepared by melt mixing using a melt kneading device such as an extruder. Molding from the composition may be carried out immediately after melt-mixing, or after melt-mixing, once pelletized, it may be molded by another melt-molding machine. Although various known molding methods can be adopted for molding, injection molding is particularly suitable for the thermoplastic resin composition of the present invention. That is, in injection molding, a relatively small amount of potassium ionomer is compounded to obtain a molded article having excellent antistatic properties, and deterioration of physical properties due to the compounding of potassium ionomer can be minimized. It is considered that this is because the ionomer component is dispersed in the matrix resin in a state closer to a continuous layer due to the orientation during injection molding.

The composition of the present invention is an antistatic composition in which a polymer compound is blended with a thermoplastic resin, but is excellent in that the blending does not impair the properties of the thermoplastic resin. In particular, methacrylic resin has excellent transparency and surface gloss, and it is being industrially utilized by making the most of it. 0.1% by weight of other colorless and transparent resin such as polystyrene and AS resin is added to this methacrylic resin. It is known that the molded product becomes cloudy even if mixed to some extent. Also, even if a small amount of a zinc salt of an ethylene / methacrylic acid random copolymer, which is one of the ionomers, is mixed in, the molded product will also become cloudy.
However, surprisingly, the composition comprising the methacrylic resin and the potassium ionomer of the present invention substantially retains the original transparency and surface gloss of the methacrylic resin. Not only does this give the potassium ionomer excellent transparency,
It is presumed that the compatibility with the methacrylic resin is extremely good.

[0026]

EFFECT OF THE INVENTION The thermoplastic resin composition of the present invention has a good antistatic property, is excellent in sustainability, and has no stickiness on the surface of the molded product over time.
As a sheet and various molded articles, it can be widely used in fields where antistatic property is required, for example, automobile parts, OA equipment, home appliance parts, or storage / storage cases thereof, stationery, daily necessities, and the like.

[0027]

EXAMPLES The present invention will be specifically described with reference to the following examples. The composition and physical properties of the potassium ionomer and the thermoplastic resin used in the composition of the examples and comparative examples are as follows.

(1) Ionomer Ionomer 1: Acrylic acid content 21% by weight Neutralization degree 80 mol% K ion concentration 2.3 mol / kg Ionomer MFR 0.6 g / 10min (190 ° C., 2160 g load)

Ionomer 2: PEG is added to ionomer 1.
(Sanyo Kasei polyethylene glycol PEG 600 average molecular weight 600) blended (PEG concentration: 5% by weight) K ion concentration 2.2 mol / kg ionomer

(2) Thermoplastic resin The resin shown in Table 1 was used.

[0031]

[Table 1]

Examples 1 to 4 The ABS resin, the ionomer 1 or the ionomer 2 and the ethylene copolymer used as the compatibilizing agent were mixed at the compounding ratios shown in Table 2, and then mixed in a small mixer (Toyo Seiki Labplast. Melt kneading for 10 minutes at 230 ° C. The obtained composition is pressure-molded at 200 ° C.,
A sheet having a thickness of 2 mm was used. This test piece was heated at 23 ° C, 50
After being placed under the temperature and humidity conditions of% relative humidity and 60% relative humidity for 24 hours, the surface resistivity was measured under the same conditions using a high resistivity meter Hiresta IP manufactured by Mitsubishi Petrochemical Co., Ltd.
The results are shown in Table 2. Commercially available antistatic ABS resin 60
The surface resistivity measured in% relative humidity is 2 x 1
Since it was 0 ¹³ (Ω), it can be said that these compositions are antistatic.

Examples 5 to 7 Polystyrene, nylon 6, PMMA and ionomer 1
Was mixed in the composition shown in Table 3, and a test piece was prepared from the compositions prepared in the same manner as in Examples 1 to 4 at the melt-kneading temperature and the pressure molding temperature shown in Table 3 to obtain the surface resistance. The rate was measured. Table 3 shows the measurement results of the surface resistivity. Example 5
The surface resistivities of the compositions obtained in Example 7 were all small enough to show non-chargeability.

Examples 8 and 9 ABS resin, ethylene copolymer, and ionomer 1
Was mixed in the same mixing ratio as in Examples 3 and 4 as shown in Table 4, and then a twin-screw extruder (screw diameter 29 mm, L
/ D = 25), resin temperature 230 ° C., extrusion rate 8
It was melt-kneaded at a rate of kg / h and granulated. A test piece having a thickness of 2 mm was prepared from the above composition by an injection molding method. The surface resistivity of this test piece was measured by the same method as in Examples 1 to 4. The results are shown in Table 4.

Even if the composition is the same, the surface resistivity tends to be lower in the case of molding by the injection molding method than in the case of the test pieces of Examples 3 and 4 obtained by the pressure molding method. It was This is considered to be because, in injection molding, the ionomer component is dispersed in the matrix resin in a state close to a continuous layer due to orientation during molding, whereas in pressure molding, orientation does not occur, and the result does not appear.

Examples 10 and 11 ABS resin and ionomer 1 or ionomer 2
Was mixed in the mixing ratio shown in Table 4, and a test piece having a thickness of 2 mm was prepared from the composition prepared in the same manner as in Examples 8 and 9 by an injection molding method. About this test piece, Example 1
Surface resistivity was measured by the same method as ~ 4. The results are shown in Table 4.

Comparative Examples 1-4 ABS resin, polystyrene, nylon 6, and PMMA
The pellets of No. 1 were not individually blended with the ionomer, but each was pressed alone at a temperature shown in Table 5 to prepare a test piece having a thickness of 2 mm, and the surface resistivity was measured by the same method as in Examples 1 to 4. . The results are shown in Table 5. It can be seen that the resin having no potassium ionomer as it is has a high surface resistivity and a large charging property.

Comparative Examples 5-8 Polyethylene terephthalate, polybutylene terephthalate, low density polyethylene, and polypropylene were mixed with Ionomer 1 at the compounding ratios shown in Table 6, and then compositions prepared in the same manner as in Examples 1 to 4. A test piece was prepared from and the surface resistivity was measured. However, the melt-kneading and pressure molding temperatures are as shown in Table 6. Table 6 shows the measurement results of the surface resistivity. Although the potassium ion concentrations in the compositions obtained in Comparative Examples 5 to 8 were the same as those in Examples 5 to 7, the surface resistivity of the compositions was high when blended with these polymers. It showed chargeability.

[0039]

[Table 2]

[0040]

[Table 3]

[0041]

[Table 4]

[0042]

[Table 5]

[0043]

[Table 6]

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area C08L 23:26)

Claims (4)

[Claims] 1. A thermoplastic resin 75 to 99 selected from polyamide resins, methacrylic resins, and styrene polymers.
A thermoplastic resin composition comprising 1 wt% to 25 wt% of a potassium ionomer of an ethylene / (meth) acrylic acid random copolymer having a potassium ion concentration of 1.5 mol / kg ionomer or more. 2. 20% by weight or less of the ionomer,
The thermoplastic resin composition according to claim 1, further comprising a polyoxyalkylene polyol which is liquid at 25 ° C. 3. The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin component is an ABS resin. 4. An injection-molded article made of the thermoplastic resin composition according to claim 1.