JPH07117142A - Antistatic methacrylic resin molding - Google Patents

Abstract

PURPOSE:To provide an antistatic methacrylic resin molding that can be wiped for cleaning without loosing the antistatic properties thereof. CONSTITUTION:An antistatic methacrylic resin molding is composed of a methacrylic resin prepared by adding 0.5-5 pts.wt. of at least one kind of an antistatic agent selected from a hydrocarbon compd. having sulfonate, higher fatty acid monoglyceride and polyalkylene glycol to 100 pts.wt. of a methyl methacrylate polymer and characterized by that the ten-score average roughness (Rz) of the surface thereof is 1-30mum and the average ridge interval (Sm) thereof is 10-3000mum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antistatic treatment for a lighting cover, a diffusion plate for a display, a signboard, a light-emitting switch button, a cover for an exhibit display, an interior / exterior part of an automobile, an exterior part of a household electric appliance, and the like. Methacrylic resin molded article.

[0002]

BACKGROUND OF THE INVENTION Methacrylic resin is widely used for lighting equipment, signboards, various ornaments, nameplates, etc. due to its excellent transparency, good mechanical properties, processability and beauty of molded products. Due to its large surface electrical resistivity, static electricity induced by contact or friction is unlikely to escape and disappear, and as a result dust and other substances are likely to adhere to the resin surface during use and stain easily, resulting in a loss of its beautiful appearance. ing.

Therefore, various compositions have been proposed in which various antistatic agents are mixed in an acrylic resin. For example, JP-A-47-26438 discloses a resin composition containing an aromatic compound having a sulfonic acid group and a polyether, as disclosed in JP-A-1-1975.
Japanese Unexamined Patent Publication (Kokai) No. 4-108846 discloses a resin composition containing alkylbenzene having a sulfonic acid group and glycerin fatty acid ester, and Japanese Unexamined Patent Publication No. 4-108846 discloses a composition containing normal paraffin sulfonate. In addition, JP-A-5-1252
Japanese Patent Publication No. 47 discloses a resin composition containing glycerin monofatty acid ester, trialkyl phosphite and crosslinked fine beads.

[0004]

However, the expression of antistatic properties when these resin compositions are used as molded articles for practical use occurs when these antistatic agents bleed on the surface. On the other hand, most of the uses of the molded body are to wipe off dirt and dust on the surface thereof in order to maintain a beautiful appearance. If this wiping is carried out using a water-based material, the bleeding antistatic agent is removed and the antistatic property disappears. Further, among the antistatic agents, for example, a polyol (polyalkylene oxide compound) such as a polyol is added to reduce the heat resistance of the acrylic resin.

Therefore, the present invention provides a methacrylic resin molded product which can be continuously exerted without losing its antistatic property even if the surface is wiped off and the heat resistance is maintained.

[0006]

Means for Solving the Problems That is, the present invention is based on 100 parts by weight of a methyl methacrylate polymer, and at least one selected from a hydrocarbon compound having a sulfonate group, a higher fatty acid monoglyceride, and a polyalkylene glycol. It is made of a methacrylic resin containing 0.5 to 5 parts by weight of an antistatic agent, and its surface has a ten-point average roughness (Rz) of 1 to 30 μm and an average mountain interval (Sm) of 1.
The present invention provides an antistatic methacrylic resin molded product having a thickness of 0 to 300 μm.

The methyl methacrylate polymer used in the present invention includes methyl methacrylate homopolymer or methyl methacrylate in an amount of 50% by weight or more, and methyl methacrylate and a copolymerizable monomer such as ethyl methacrylate,
Butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl methacrylate, and other methacrylate esters, methyl acrylate, ethyl acrylate, butyl acrylate, acrylic acid Cyclohexyl, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, 2-acrylic acid
Acrylic ester such as hydroxyethyl, unsaturated acid such as methacrylic acid, acrylic acid, styrene, α-methylstyrene, acrylonitrile, methacrylonitrile, maleic anhydride, phenylmaleimide, cyclohexylmaleimide, etc. However, the present invention is not limited to these. Further, it may further contain an elastomer component such as polybutadiene, a butadiene / butyl acrylate copolymer, a polybutyl acrylate copolymer, a glutaric anhydride unit, or a glutarimide unit.

These methacrylic resins can be obtained by known polymerization methods such as bulk polymerization method, suspension polymerization method, emulsion polymerization method and solution polymerization method. The shape of methacrylic resin is so-called pellet, powder, beads, or
It is possible to use a pulverized amorphous product or a molten product.

The hydrocarbon compound having a sulfonate group used in the present invention is a compound represented by the following formula [Chemical formula 1], which is well known as an antistatic agent for various thermoplastic resins.

[0010]

[Chemical formula 1] R-SO ₃ X

In the formula, R may be either an aliphatic hydrocarbon or an aromatic hydrocarbon. Of these, straight-chain hydrocarbon groups having 12 to 18 carbon atoms are preferable. X is sodium,
Alkali metals such as potassium and lithium.

The higher fatty acid monoglyceride of the present invention is
The higher fatty acid has 12 to 22 carbon atoms.

The polyalkylene glycol is represented by the following [Chemical formula 2].

Embedded image R ² O (R ¹ O) _n R ³ (wherein R ^{1 is} a hydrocarbon group having 2 to 4 carbon atoms, R ² ,
R ³ : a hydrocarbon group having 1 to 10 carbon atoms, n: 50 or more 10
Represents 0. )

Among these antistatic agents, a hydrocarbon compound containing a sulfonic acid group represented by [Chemical Formula 1] is more preferable. The amount of these antistatic agents is 0.5 to 5 parts by weight, based on 100 parts by weight of the methyl methacrylate polymer.
It is preferably 1 to 3 parts by weight. If it is less than 0.5 part by weight, the antistatic property is not sufficiently exhibited. Further, if the amount is more than 5 parts by weight, the processing machine is contaminated when the molded product is processed, and the surface of the molded product becomes sticky.

As a method of mixing these antistatic agents in the methyl methacrylate polymer, there is a known method of mixing both with a Henschel mixer or the like and melt-kneading with an extruder or an injection molding machine. However, it may be adjusted at the time of molding described later.

In the present invention, as the surface roughness of the molded product, a ten-point average roughness (hereinafter Rz) and an average mountain interval (hereinafter Sm) are used. Both Rz and Sm are JIS-B0601.
-Follow those described in 1982, "Definition and representation of surface roughness".

The value of Rz is 1 to 30 μm, preferably 5
Is about 20 μm. If it is less than 1 μm or more than 30 μm and large, the ability to hold the antistatic agent is lowered and the antistatic property is lowered.

The value of Sm is 10 to 300 μm, preferably 50 to 200 μm, and even if it is less than 10 μm, it is 300.
Even if it is larger than μm, the ability to hold the antistatic agent decreases.

A known method may be used to make the surface of the molded article of the present invention have a predetermined roughness, and the method is not particularly limited. For example, a processing method called mat processing or embossing is used. This method melts the resin in a soft state,
It is a method of pressing and transferring to a hard material with unevenness,
There are respective means depending on the method of obtaining the molded body.

If the molded body is plate-shaped, for example, resin
This is a method for producing a resin plate by so-called extrusion molding in which it is extruded from a die into a plate shape, sandwiched between rolls and cooled, and disclosed in Japanese Examined Patent Publication No. Sho 47-24475, Plastic Material Course [12] Acrylic resin (March 25, 1970). As described in Nikkan Kogyo Shimbun Co., Ltd.) and Japanese Patent Publication No. 60-1185, there is a method using a roll with a mold, so-called chevrolol.

In an injection molding method for forming molded articles of various shapes, a mold having a grained inner surface is used.

In these methods, since the transfer is performed, it is sufficient to use those in which the texture of the embossing roll or the embossing die gives the above-mentioned roughness to the surface of the molded body.

As another method, for example, Japanese Patent Publication No.
As described in 0-2178 or JP-A-57-14650, organic fine particles and inorganic fine particles which are not melted at a temperature at which a methacrylic resin is melt-kneaded are mixed,
There is a method of forming a rough surface by allowing the mixed fine particles to float on the surface of the molded body. If the particles are spherical, the antistatic property is further improved.

Examples of the fine particles to be mixed include organic particles such as a styrene polymer, an acrylic polymer and a siloxane polymer, which have a particularly high molecular weight or a copolymer with a polyfunctional monomer. Crosslinked polymers are suitable.
Specific examples of the inorganic particles include barium sulfate, calcium carbonate, silica, alumina, magnesia, mica, talc, aluminum hydroxide, titanium carbide, glass beads,
Examples include calcium silicate.

To obtain a predetermined surface roughness, it is adjusted by the particle size of the fine particles and the addition amount. Both the Rz and Sm values increase as the particle size of the particles increases. The larger the added amount, the smaller the Sm value.

Therefore, as a guide, the average particle size is 1 to 100 μm.
The predetermined roughness may be obtained by several trials on the assumption that about 1 to 20 parts by weight of particles of about m are mixed.

To mix these particles, a well-known method of melt-kneading with a methyl methacrylate polymer may be used,
It may be mixed at the same time as the above-mentioned antistatic agent is mixed. Then, it may be shaped into a predetermined shape by an ordinary molding method through an extruder or an injection molding machine. After the shaping, the slower the cooling, the easier the surface roughness becomes.

[0028]

EFFECT OF THE INVENTION The methacrylic resin molded product of the present invention has excellent antistatic properties, and even when the surface thereof is wiped, the antistatic properties are maintained without loss. The molded product is used for interior and exterior parts of automobiles such as lighting covers, display diffusion plates, signboards, light-emitting switch buttons, covers for display of articles, meter covers, and exterior parts of household electric appliances.

[0029]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. The evaluation method is as follows.・ Antistatic property: After leaving the acrylic resin plate at 23 ° C. and 50% humidity for 24 hours, an applied voltage of 10 was applied in the same atmosphere using a static Honest meter (manufactured by Shishido Shokai).
The half-life of the charged voltage is measured under the conditions of Kv, application time of 1 minute and table rotation speed of 1300 rpm.・ Wipe resistance: 5 g of acrylic resin plate with gauze moistened with water
After being wiped off once, and allowed to stand for 24 hours at 23 ° C. and 50% humidity, the antistatic property was evaluated in the same manner as above.・ Surface roughness: In accordance with JIS-B0601-1982, a ten-point average roughness (R
z) and the average mountain interval (Sm) were measured.

Example 1 100 parts by weight of methacrylic resin beads (SUMIPEX EXA, manufactured by Sumitomo Chemical Co., Ltd.) and 1 part by weight of sodium n-hexadecylsulfonate were mixed in a Henschel mixer, and then an extruder (uniaxial, With a screw diameter of 40 mm, manufactured by Tanabe Plastic Co., Ltd., a resin sheet is extruded from a T die at a resin temperature of 265 ° C., and the first roll is a polishing roll, and the second roll is a polishing roll.
No. 1 roll has a pattern unit with Rz = 50 μm and Sm = 120 μm, and No. 3 roll has a polishing roll. The surface temperature of No. 1 roll is 120 ° C., the surface temperature of No. 2 roll is 140 ° C., the surface of No. 1 roll. Temperature 130
A sheet having a thickness of 2 mm and a width of 25 cm was obtained at ℃. The evaluation results of the obtained sheet are shown in Table 1.

Example 2 The pattern roll of No. 2 roll in Example 1 was Rz =
A sheet having a thickness of 2 mm was similarly obtained by setting 5 μm and Sm = 70 μm. The evaluation results are shown in Table 1.

Example 3 A 2 mm thick sheet was obtained in the same manner as in Example 1 except that 1 part of sodium n-hexadecylsulfonate was replaced with 3 parts of sodium laurylbenzenesulfonate.
The evaluation results are shown in Table 1.

Examples 4, 5 and Comparative Example 1 100 parts by weight of methacrylic resin beads (SUMIPEX MH, manufactured by Sumitomo Chemical Co., Ltd.), sodium n-hexadecylsulfonate, and crosslinked methacrylic resin beads having an average particle size of 30 μm. (SUMIPEX XC-1A manufactured by Sumitomo Chemical Co., Ltd.) was added in an amount shown in Table 1 and mixed with a Henschel mixer, and then a twin-screw devolatilizing extruder (Japan Steel Works, Ltd.) was added.
Pellets of the resin composition were obtained at a resin temperature of 240 ° C. by using TEM-30 manufactured by K.K. The pellets were molded at a molding temperature of 25 with an injection molding machine (M-140SJ manufactured by Meiki Seisakusho Co., Ltd.).
Molding was carried out at 0 ° C. and a mold temperature of 60 ° C. with a round plate mold having a diameter of 120 mm to obtain a round plate molded product. The bottom of the molded product was cut out to obtain a test piece having a plate thickness of 2.5 mm. The evaluation results are shown in Table 1.

Examples 6 and 7, Comparative Examples 2 and 3 Resin pellets obtained in the same manner as in Examples 4 and 5 and Comparative Examples 1 and 2 were melted into resin sheets using the extruder used in Example 1. Except for the extrusion, a roll unit consisting of three co-polishing rolls was used.
A sheet having a thickness of 27 cm was obtained. The evaluation results of the obtained sheet are shown in Table 1.

Example 8 The procedure of Example 6 was repeated except that the antistatic agent in Example 6 was changed to a mixture of 5 parts by weight of monoglycerite stearate (RIKEN VITAM CO., LTD. Poem H-100). Got the sheet. The evaluation results are shown in Table 1.

[0036]

[Table 1]

Claims (1)

[Claims] 1. 0.5 to 5 of at least one antistatic agent selected from a hydrocarbon compound having a sulfonate group, a higher fatty acid monoglyceride, and a polyalkylene glycol based on 100 parts by weight of a methyl methacrylate-based polymer.
An antistatic methacrylic resin molding comprising a methacrylic resin in an amount of 10 parts by weight and having a surface ten-point average roughness (Rz) of 1 to 30 μm and an average pitch (Sm) of 10 to 300 μm.