JP2803830B2 - Synthetic resin molded article excellent in antistatic property and method for producing the same - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a synthetic resin molded article having good and permanent antistatic performance and a method for producing the same.

Currently, many synthetic resin molded products are commercially available, and they have many excellent properties, but generally have a high electric resistivity, so they are easily charged by friction or the like, and attract dust, dust, etc., and have an appearance. Cause problems such as spoiling.

[Conventional technology]

Methods of imparting antistatic performance to a synthetic resin molded article include (1) internal addition of a surfactant (2) surface coating of a surfactant (3) surface coating of a silicon-based compound (4) surface modification by plasma treatment Quality. Of these, (3) and (4) are both costly, so the methods (1) and (2) are generally used.

The method of internally adding a surfactant involves mixing or dispersing a surfactant into a synthetic resin raw material before polymerization or a synthetic resin before molding, so that the manufacturing process is simplified, but in order to obtain sufficient antistatic performance, In general, it is necessary to increase the amount of surfactant added. However, in this case, there is a disadvantage that the mechanical strength of the synthetic resin tends to be impaired, and the obtained antistatic performance is easily lost due to washing with water, friction and the like.

The method of applying a surfactant on the surface has the advantage that the physical properties of the synthetic resin used as the base material are not impaired and that a small amount of surfactant can provide good antistatic performance, but a surface application step is required For this reason, there is a problem that the cost may be increased, the beautiful appearance of the synthetic resin molded article may be spoiled, and the obtained antistatic performance is easily lost due to washing or friction.

Further, the present inventors have previously disclosed a cationic antistatic polymer having a quaternary ammonium base in the polymer in JP-A-63-108040. However, the cationic polymer has poor thermal stability and has a problem that it deteriorates when heated.

[Problems to be solved by the invention]

As described above, there has not been a synthetic resin molded product that exhibits good antistatic performance permanently and retains the original physical properties of the synthetic resin.

[Means for solving the problem]

The present inventors have conducted intensive studies on the above problems,
After forming a film of a certain kind of anionic polymer on at least one mold surface of a mold composed of a pair, by using the mold to polymerize the raw material of the synthetic resin serving as the base material, It has been found that a synthetic resin molded article having permanent antistatic performance can be obtained.

That is, the present invention relates to a method for preparing a resin of the general formula (I) (In the above formula, R ₁ represents a hydrogen atom or a methyl group, and A ₁ is Represents, R ₂ , R ₃ , R ₄ and R ₅ may be the same or different, each represents an alkyl group optionally having a substituent, an aryl group or an aralkyl group, n represents 0, 1 or 2, B represents an alkylene group which may have an ester bond, an arylene group or an aralkylene group,
R ₆ represents a hydrogen atom or an alkyl group] or an monomer comprising at least 80% by weight of at least one monomer copolymerizable with 20% by weight or more of the monomer A film of an antistatic polymer obtained by polymerizing the mixture is formed. Provide a synthetic resin molded article having excellent antistatic properties. This molded article is formed by forming a film of an antistatic polymer obtained by polymerizing the monomer mixture on at least one mold surface of a pair of molds, and then using a raw material of a synthetic resin as a base material as a mold. And then polymerized and cured to transfer the film from the mold surface to the substrate surface, and then take out the molded product from the mold.

The anionic antistatic polymer has good thermal stability, hardly deteriorates during polymerization curing at a high temperature and during heat processing, and is more advantageous than a cationic antistatic polymer.

Specific examples of the anionic monomer of the general formula (I) useful in the present invention include tetraethylphosphonium vinylsulfonate, tetrabutylphosphonium vinylsulfonate, tetramethylolphosphonium vinylsulfonate and tetraallylsulfonic acid tetraethylphosphonate. Butylphosphonium salt, tetralauryl phosphonium salt of methallyl sulfonic acid, tributyl methyl phosphonium salt of sulfoethyl methacrylate, triethyl butyl phosphonium salt of sulfoethyl acrylate, tetrabutyl phosphonium salt of sulfopropyl acrylamide, trimethylol butyl phosphonium salt of sulfopropyl methacrylamide trimethylol butyl phosphonium salt, styrene sulfonic acid Tetrabutylphosphonium salt, tetramethylolphosphonium styrenesulfonate, triethylmethyl α-methylstyrenesulfonate Phosphonium salts and the like.

These anionic monomers can be freely selected depending on the type of the base synthetic resin. For example, when the base synthetic resin is a methyl methacrylate resin, from the viewpoint of compatibility with the methyl methacrylate resin and availability of raw materials, 2-acrylamido-2-methylpropane phosphonium phosphonium salts, sulfoethyl ( Meth) acrylate phosphonium salts and styrene sulfonate phosphonium salts are preferred, and butyl phosphonium salts and ethyl phosphonium salts thereof are particularly preferred.

As the monomer copolymerizable with the anionic monomer component represented by the general formula (I), a known monomer can be used.
For example, methyl methacrylate, methacrylates such as ethyl methacrylate, methyl acrylate, acrylates such as ethyl acrylate, acrylic acid, unsaturated carboxylic acids such as methacrylic acid, maleic anhydride, acid anhydrides such as itaconic anhydride, Maleimide derivatives such as N-phenylmaleimide, hydroxy-containing monomers such as 2-hydroxyethyl acrylate and 2-hydroxypropyl methacrylate, nitrogen-containing monomers such as acrylamide and acrylonitrile, and epoxy groups such as allyl glycidyl ether and glycidyl acrylate Containing monomer, bifunctional monomer such as allyl methacrylate, allyl acrylate, terminal methacrylate polymethyl methacrylate, terminal styryl polymethyl methacrylate, terminal methacrylate polystyrene , Terminal methacrylate polyethylene glycol, high molecular monomers such terminal methacrylate acrylonitrile-styrene copolymer.

As monomers of these copolymers, general formula (II) (In the above formula, R ₇ represents a hydrogen atom or a methyl group, R ₈ represents a hydrogen atom, an alkyl group having no copolymerizable functional group having 1 to 18 carbon atoms, an aralkyl group or an aryl group; Wherein m represents an alkylene group having 2 to 4 carbon atoms and m represents an integer of 0 to 500), and / or a compound having two or more unsaturated double bonds capable of being copolymerized. Preferably, two or more compounds selected from the above two compounds are used in combination.

In the compound represented by the general formula (II), those represented by m = 0 include methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, lauryl methacrylate,
Examples thereof include 2-ethylhexyl methacrylate, stearyl methacrylate, benzyl methacrylate, phenyl methacrylate, cyclohexyl methacrylate, and 2-hydroxyethyl methacrylate.

Examples of m = 2 to 500 include polyethylene glycol (4) monomethacrylate, polyethylene glycol (23) monoacrylate, polyethylene glycol (23) monomethacrylate, polyethylene glycol (300) monomethacrylate, and polypropylene glycol ( 23) monomethacrylate, polybutylene glycol (23) monomethacrylate, polyethylene glycol (23) monomethacrylate monomethyl ether,
Polyethylene glycol (23) monomethacrylate monobutyl ether, polyethylene glycol (23) monomethacrylate monostearyl ether, polyethylene glycol (23) monomethacrylate monophenyl ether, polyethylene glycol (23) monomethacrylate monobenzyl ether, polyethylene glycol (23)
Monomethacrylate monooleyl ether (the number in parentheses is the number of polyalkylene glycol units).

The copolymerizable monomer is the same as the monomer unit constituting the synthetic resin as the base material or the same as the monomer unit constituting the synthetic resin having good compatibility with the synthetic resin as the base material. This is preferable from the viewpoint of improving the adhesion between the copolymer imparting antistatic properties and the synthetic resin as the base material.

For example, when the base synthetic resin is a polymer having methyl methacrylate as a main component, in the general formula (II), m =
Since the adhesiveness between the base synthetic resin and the copolymer imparting antistatic properties is improved when the resin represented by 0 is used, a film of the copolymer imparting antistatic properties may remain in the mold at the time of peeling. And a stable antistatic property can be exhibited using any type of template. Further, when a compound represented by m = 2 to 500 in the general formula (II) is used, the releasability of the obtained synthetic resin molded product from the mold, particularly the releasability at high temperatures, tends to be improved, An antistatic synthetic resin molded product can be stably obtained.

Examples of the copolymerizable monomer having two or more unsaturated double bonds include allyl acrylate, methallyl acrylate, vinyl acrylate, allyl methacrylate, methallyl methacrylate, vinyl methacrylate, 1-chlorovinyl methacrylate, and isopropenyl methacrylate. , N-methacryloxymaleimide, ethylene glycol dimethacrylate, butanediol dimethacrylate, polyethylene glycol dimethacrylate, allyl vinyl ether, allyl vinyl ketone, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate, triallyl cyanurate and the like.

When these compounds having two or more copolymerizable unsaturated double bonds are used, the copolymer film of the present invention has a crosslinked portion and a residual double bond, and these have the strength of the film itself. And contributes to the formation of a semi-IPN structure with the base synthetic resin and the formation of a chemical bond with the base by graft polymerization of the monomer to the remaining double bond. And the surface hardness of the obtained molded article and the adhesion between the base synthetic resin and the copolymer film, that is, the permanent antistatic property are improved.

In particular, when at least one of the functional groups is a polymer group having lower polymerizability than methacryloyl groups and acryloyl groups such as allyl group, methallyl group, vinyl group, vinylidene group and vinylene group, and unreacted in the polymer antistatic agent, Heavy bonds remain, to perform graft polymerization during the polymerization of the base synthetic resin,
It is preferable from the viewpoint of adhesion between the copolymer film imparting antistatic properties and the base synthetic resin.

As the monomer copolymerizable with the anionic monomer component represented by the general formula (I), particularly when the base synthetic resin is a methyl methacrylate-based polymer, (a) the general formula (II)
Among the compounds represented by the compound, m = 2-500,
(B) Among the compounds represented by the general formula (II), those in which m = 0, particularly methyl methacrylate and (c) a compound having two or more copolymerizable unsaturated double bonds, particularly allyl methacrylate or allyl It is preferable to use three or more acrylates in combination.

The composition of the antistatic polymer in the present invention is represented by the general formula (I):
Is 20 to 100% by weight, preferably 20 to 80% by weight, and 0 to 80% by weight, preferably 20 to 80% by weight of a copolymerizable monomer. If the amount of the anionic monomer component represented by the general formula (I) in the copolymer is less than 20% by weight, good antistatic properties cannot be imparted to the resulting synthetic resin molded product, for example, a methacrylic resin cast plate. A monomer other than the copolymerizable monomer represented by the general formula (I) is
It is preferable to use it in an amount of at least% by weight from the viewpoint of improving the adhesion between the antistatic polymer and the synthetic resin as the base material.

In particular, when the base synthetic resin is a methyl methacrylate resin, an anionic monomer represented by the general formula (I) 20
To 70% by weight, and 24.9 to 74.9% by weight of a monomer represented by m = 2 to 500 in the general formula (II) among other copolymerizable monomers; M in II)
= 0 to 5% by weight of a monomer represented by formula (C) = 0 and (c) a compound having two or more unsaturated double bonds capable of being copolymerized.
Most preferably, it is by weight.

Further, the molecular weight of the antistatic polymer in the present invention is preferably 1,000 or more. If it is less than 1000, a film having good permanent antistatic performance may not be obtained.

In the present invention, permanent antistatic properties are exhibited because the polymer film is integrated with the base synthetic resin. That is, the film formed on the mold surface swells with the raw material of the synthetic resin during the polymerization of the base synthetic resin, and in this state, the polymerization proceeds, and the surface of the molded article after polymerization is integrated with the film. Unlike the method of applying a coating, the molded article of the present invention does not lower its antistatic performance even by washing with water or friction. Further, the present invention shows good antistatic performance even in a small amount because the polymer film is present only on the surface of the molded article.

The raw material of the base synthetic resin used in the present invention is not particularly limited, and methyl methacrylate, styrene, other polymerizable monomers and their partial polymers, polyol and polyisocyanate, both-end epoxy oligomer and polyamine or polyamide , Unsaturated polyesters, nopolak polymers and bisoxadrines, reactive silicone rubber oligomers, and cyclic polycarbonate oligomers.

Most preferred as the base synthetic resin used in the present invention is methyl methacrylate or methyl methacrylate.
A methacrylic resin is obtained from a monomer mixture composed of 50% by weight or more and 50% by weight or less of at least one monomer copolymerizable therewith or a partial polymer thereof.

Monomers copolymerizable with methyl methacrylate include ethyl methacrylate, butyl methacrylate,
Methacrylates such as -ethylhexyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, acrylates such as 2-ethylhexyl acrylate, acrylic acid, methacrylic acid,
Unsaturated carboxylic acids such as maleic acid and itaconic acid, acid anhydrides such as maleic anhydride and itaconic anhydride, N-phenylmaleimide, N-cyclohexylmaleimide, Nt-
Maleimide derivatives such as butyl maleimide, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, hydroxy group-containing monomers such as 2-hydroxypropyl methacrylate, acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, Nitrogen-containing monomers such as diacetone acrylamide and dimethylaminoethyl methacrylate; epoxy-containing monomers such as allyl glycidyl ether, glycidyl acrylate and glycidyl methacrylate; styrene monomers such as styrene and α-methylstyrene; ethylene glycol Diacrylate, allyl acrylate, ethylene glycol dimethacrylate,
Examples include cross-linking agents such as allyl methacrylate, divinylbenzene, and trimethylolpropane triacrylate, but are not particularly limited thereto.

The type and amount of the copolymerizable monomer can be determined according to the intended synthetic resin molded product.

In addition, additives such as a colorant, a release agent, an ultraviolet absorber, a heat stabilizer, and various fillers can be mixed and used in the base synthetic resin raw material of the present invention.

Specific examples of the mold used in the present invention include those made of inorganic glass such as tempered glass, metal such as stainless steel, aluminum and chromium plating, and resin such as polyester resin. The mold surface of glass, metal, or the like is generally a mirror surface. However, in some cases, a surface having fine irregularities on the surface and subjected to a matting treatment may be used according to the purpose.

In the present invention, when a copolymer film is formed on a mold surface, it is a simple and preferred method to apply the copolymer (a) in the form of a solution of water and / or an organic solvent.
In particular, when the base synthetic resin is a methacrylic resin, the antistatic polymer is a vinyl monomer 50 copolymerizable with methyl methacrylate or 50% by weight or more of methyl methacrylate.
It is more preferable to apply the mixture on the mold surface in the form of a monomer mixture of not more than% by weight or a mixture with a partial polymer thereof from the viewpoint of adhesion to the base synthetic resin and solvent residue.

Release agents, defoamers, and leveling as long as the antistatic performance of the film obtained from the solution or mixture, the polymerizability of the base synthetic resin material, and the physical properties of the base resin are not impaired with respect to the above solution or mixture. Components such as an agent, various monomers, and a crosslinking agent can also be added.

Examples of a method for applying the above solution or mixture to the mold surface include a spray coating method, a flow coating method, a bar coating method, a dip method and the like.

In the case of manufacturing a plate-shaped methacrylic resin molded product according to the present invention, a continuous casting method using two stainless steel endless belts, each of which is mirror-polished on one side, and which proceeds in the same direction at the same speed is produced. It is preferable from the aspect of properties.

〔Example〕

Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto.

The electrical properties of all the samples were measured by adjusting the humidity at 20 ° C. and 65% relative humidity for one day. The charge half-life was measured using a static honest meter (manufactured by Shishido Shokai) under the conditions of an applied voltage of 10,000 V, a sample rotation speed of 1550 rpm, an applied time of 30 seconds, a measurement temperature of 20 ° C., and a measurement humidity of 65%. The sample voltage is set to an initial voltage (V). After the voltage is applied, the time until the sample voltage becomes half of the initial voltage is defined as a charge half-life time (se
c). The surface resistivity was measured using a super insulation resistance meter (TR-8601, manufactured by Takeda Riken) at a measurement temperature of 20 ° C and a measurement humidity of 65%.
Under the conditions described above, the surface resistivity (Ω) after one minute at an applied voltage of 500 V was measured.

After washing with water, the surface resistivity was obtained by cutting the obtained plate into 40 mm × 40 mm, and wiping the plate strongly 60 times with gauze under running water using the above super insulation resistance meter.

The surface hardness was measured based on a pencil scratch test in JIS K5400 (General paint test method).

Transparency was measured for haze using an integrating sphere haze meter (SEP-H-SS, manufactured by Nippon Seimitsu Kogaku).

Example 1 A glass flask equipped with stirring blades was charged with 312.4 parts of 2-acrylamide 2-methylpropanesulfonic acid and methanol 4
Into 50 parts, 1042.8 parts of a 40% methanol solution of tetrabutylphosphonium hydroxide was added dropwise at 30 ° C. or lower while stirring vigorously. After completion of the dropwise addition, the mixture was stirred for 30 minutes to obtain an anionic monomer (M-1) solution. To the resulting anionic monomer (M-1) solution, 4 parts of azobisisobutyronitrile, 3 parts of n-octylmercaptan, 200 parts of methanol
And 702 parts of polyethylene glycol (23) monomethacrylate monomethyl ether, and the mixture was polymerized at 60 ° C. under a nitrogen atmosphere for 4 hours. After the polymerization, vacuum drying was performed to obtain an antistatic polymer (P-1).

5% by weight of the above polymer (P-1) was dissolved in 95% by weight of ethanol to prepare a coating material, and the length was 600 mm, the width was 450 mm, and the thickness was 3 m.
A single-sided mirror-polished stainless steel plate was spray-coated on the mirror side and dried. Using two stainless steel plates and a gasket treated in this way,
m, a methyl methacrylate partial polymer [viscosity 1000 centipoise (20 ° C.), polymerization rate 20%] as a base synthetic resin raw material, 100 parts by weight, and a polymerization initiator of 2,2 '-Azobisisobutyronitrile 0.0
After dissolving 5 parts by weight, the solution under reduced pressure to remove dissolved air was poured. Polymerization is 10 hours at 60 ° C, then 110 ° C
For 4 hours. Thereafter, the temperature was returned to normal temperature and the mold was released from the mold. The surface resistivity of the obtained methacrylic resin plate was 4.3 × 10 ¹⁰ Ω, the charge half life was 1 second, and the haze value was 1.0%.

Further, the obtained plate was washed with water and immediately evaluated for antistatic production. As a result, the surface resistivity was 9.5 × 10 ¹⁰ Ω and the charge half life was 1 second. In addition, when the surface hardness was measured according to JIS K5400 and a pencil scratch test, it was B.

Example 2 A glass flask equipped with stirring blades was charged with 156.7 parts of 2-acrylamide 2-methylpropanesulfonic acid and methanol 2
20 parts were added, and while stirring vigorously, 523.1 parts of a 40% methanol solution of tetrabutylphosphonium hydroxide was added dropwise at 30 ° C. or lower. After completion of the dropwise addition, the mixture was stirred for 30 minutes to obtain an anionic monomer (M-1) solution. To the obtained anionic monomer (M-1) solution, 3 parts of azobisisobutyronitrile, 2 parts of n-octylmercaptan, and 80 parts of methanol
Parts, 470 parts of polyethylene glycol (23) monomethacrylate monomethyl ether, 352 parts of methyl methacrylate
And 35 parts of allyl methacrylate, and the mixture was polymerized at 60 ° C. under a nitrogen atmosphere for 5 hours to obtain an antistatic polymer (P-2) solution.

5% by weight of a solution of the above polymer (P-2) was dissolved in 95% by weight of ethanol to prepare a coating material. The length was 600 mm, the width was 450 mm,
A 3 mm-thick single-side mirror-polished stainless steel plate was spray-coated on the mirror side and dried. Using two stainless steel plates thus treated and a gasket, a methyl methacrylate partial polymer (having a viscosity of 10
For 100 parts by weight of 100 centipoise (20 ° C., polymerization rate: 20%), 0.05 parts by weight of 2,2′-azobisisobutyronitrile was dissolved as a polymerization initiator, and the dissolved air was removed under reduced pressure. Poured. Polymerization at 60 ° C for 10 hours, 110 ° C
For 4 hours. The resulting methacrylic resin plate has a surface resistivity of 6.3 × 10 ¹⁰ Ω, a charge half-life of 1 second, and a haze of 1.0%.
Met.

Further, the obtained plate was washed with water and immediately evaluated for antistatic performance. As a result, the surface resistivity was 6.5 × 10 ¹⁰ Ω and the charge half life was 1 second. Further, the surface hardness was measured according to the JIS K5400 pencil scratch test and found to be 3H.

Comparative Example 1 A methacrylic resin plate having a thickness of 3 mm was obtained in the same manner as in Example 1 except that a stainless steel mirror plate not treated with an antistatic polymer was used.

The sheet had a surface resistivity of 10 ¹⁶ Ω or more, a charge half life of 120 sec or more, a haze of 1.0%, and a surface hardness of 3H.

Example 3 A methacrylic resin plate having a thickness of 3 mm was obtained in the same manner as in Example 1 except that a tempered glass plate having a length of 600 mm, a width of 450 mm and a thickness of 6 mm was used as a mold.

The surface resistivity of this resin plate was 5.5 × 10 ⁹ Ω, the charge half life was 1 second, the haze value was 1.0%, and the surface hardness was HB.

The surface resistivity after washing with water was 6.7 × 10 ¹⁰ Ω, and the charge half-life was 1 second.

Example 4 The same procedure as in Example 1 was carried out except that a polyester film (Lumirror, Toray, standard type 250μ) bonded to the surface of a stainless steel plate 600 mm long, 450 mm wide and 3 mm thick was used as a mold. Thus, a methacrylic resin plate having a thickness of 3 mm was obtained.

The surface resistivity of this resin plate was 9.3 × 10 ⁹ Ω, the charge half-life was 1 second, and the surface hardness was B.

The surface resistivity after washing with water was 6.1 × 10 ¹⁰ Ω, and the charge half-life was 1 second.

Example 5 Copolymer (P-1) 2.0% by weight, methyl methacrylate 51.0% by weight, methyl methacrylate partial polymer (viscosity
A methacrylic resin plate having a thickness of 3 mm was obtained in the same manner as in Example 1 except that a mixed solution of 100 centipoise and a polymerization rate of 8%) was used as a coating material and applied to a mold with a bar coater.

The surface resistivity of this resin plate was 1.2 × 10 ¹⁰ Ω, the charge half life was 1 second or less, and the haze was 1.0%.

The surface resistivity after washing with water was 1.5 × 10 ¹⁰ Ω, and the charge half-life was 1 second or less.

In addition, when the surface hardness was measured according to JIS K5400 and a pencil scratch test, it was H.

Example 6 An experiment was conducted in the same manner as in Example 2 except that 5 parts of ethylene glycol dimethacrylate was used instead of 18 parts of allyl methacrylate, to obtain a methacrylic resin plate.

The surface resistivity of the obtained methacrylic resin plate is 8.2 × 10 ¹⁰
Ω, charge half-life time 1 second, haze value 1.0%.

Further, the obtained plate was washed with water and immediately evaluated for antistatic performance. As a result, the surface resistivity was 7.9 × 10 ¹⁰ Ω and the charge half life was 1 second. Further, the surface hardness was measured according to JIS K5400 and a pencil scratch test and found to be 3H.

Examples 7 to 13 Polymers (P-3 to P-9) having the compositions shown in Table 2 were obtained in the same manner as in Example 1 using the monomer (M-1) solution.

Using these polymers, the thickness was determined in the same manner as in Example 1.
A 3 mm methacrylic resin plate was obtained.

 Table 2 shows the evaluation results.

However, in Examples 7, 8, and 13, a methyl methacrylate monomer was used as the base synthetic resin raw material instead of the methyl methacrylate partial polymer.

In Examples 7 and 13, it was very difficult to release from the mold.

Examples 14 to 16 Various monomers were obtained in the same manner as in Example 1 except that a sulfonic acid-containing monomer having a quaternary ammonium group shown in Table 1 was used.

Using a monomer (M-2 to M-4) solution shown in Table 1, a polymer (P) having a composition shown in Table 2 was prepared in the same manner as in Example 1.
-10 to P to 12).

Using these polymers, the thickness was determined in the same manner as in Example 1.
A 3 mm methacrylic resin plate was obtained.

 Table 2 shows the evaluation results.

Example 17 In this example, a continuous methacrylic resin plate making apparatus as shown in the drawing was used as a mold.

In the drawing, belts (1) and (1 ') have a width of 1.5m and thickness
1mm mirror-polished endless stainless steel belt. The belt is run at a speed of 2 m / min by driving the main pulley (2 '), the initial tension of the belt is given by providing a hydraulic cylinder on the pulleys (2), (2'), 10kg / mm ²
Is set to (3) and (3 ') are also pulleys.

Coating material (P-2) 2.0% by weight Methyl methacrylate 96.0% by weight Methanol 2.0% by weight Coating materials (5) and (5 ') were converted to belts (1) and (5') by roll coaters (6) and (6 '). 1 ') was applied to the mirror surface.

The belts coated in this way are opposed to each other, and both sides are sealed with a polyvinyl chloride hollow pipe (15) containing a considerable amount of plasticizer, and between them 100 parts of methyl methacrylate partially polymerized (average degree of polymerization 1800 Polymer content of 21%) 2,2'-azobis (2,4-dimethylvaleronitrile) 0.05 parts Tinupin P 0.01 parts of a synthetic resin raw material consisting of 0.01 part was supplied by a metering pump through an injection device.

The polymerization zone has a total length of 96m, and the first 66m section regulates the belt surface distance with idle rollers (4) and (4 ') arranged at 15cm intervals and sprays 80 ° C hot water from the outer surface of the belt from the nozzle. The belt was supported by idle rollers arranged at 1 m intervals in the latter 30 m section, heated to about 130 ° C. by an infrared heater (17), and then cooled. 3mm thick by removing from belt after cooling
Was continuously obtained.

The resin thus obtained has a surface resistivity of 3.2 × 10 ¹⁰ Ω,
The charge half-life was 1 second or less and the haze value was 1.0%.

The surface resistivity after washing with water was 2.8 × 10 ¹⁰ Ω, and the charge half-life was 1 second or less.

Further, the surface hardness was measured according to JIS K5400 and a pencil scratch test and found to be 3H.

Comparative Examples 2-3 Polymers (P-13 to P-14) having the compositions shown in Table 2 were obtained in the same manner as in Example 1 using the monomer (M-1) solution.

A methacrylic resin plate having a thickness of 3 mm was obtained in the same manner as in Example 1 using these copolymers.

 Table 2 shows the evaluation results.

Comparative Example 4 Coating type antistatic agent statiside having a quaternary ammonium base as a coating material (Analytical Chemical Labo
ratories company) (10% isopropyl alcohol solution), except that a methacrylic resin plate having a thickness of 3 mm was obtained in the same manner as in Example 1.

Although the surface resistivity of this resin plate was 1.6 × 10 ⁹ Ω and the charge half-life was 1 second or less, the surface of the resin plate had many irregularities that were partially peeled off from the mold surface during polymerization. Not worth it.

However, the symbols in the table have the following meanings.

PEG (23): Polyethylene glycol (23) monomethacrylate monomethyl ether PEG (9): Polyethylene glycol (9) monomethacrylate monomethyl ether PEG (500): Polyethylene glycol (500) monomethacrylate (number of polyethylene glycol units in parentheses) MMA: Methyl methacrylate MA: Methyl acrylate [Effects of the Invention] According to the present invention, a synthetic resin molded article having good and permanent antistatic performance and not deteriorating the physical properties of the base synthetic resin and production thereof Since a method can be provided, a trouble caused by static electricity, which has been a problem in using a synthetic resin, can be solved.

[Brief description of the drawings]

The drawing shows an example of a continuous methacrylic resin plate making apparatus provided with a coating material coating apparatus, and the reference numerals in the figure are as follows. (1), (1 ') ... endless belt, (2), (3), (2'), (3 ') ... pulley, (4), (4') ... idle roller, (5) , (5 ') ... film raw material, (6), (6') ... roll coater, (14) ... base synthetic resin raw material, (15) ... gasket, (16) ... heater, ( 17) Infrared heater.

Claims (6)

(57) [Claims] 1. A compound of the general formula (I) (In the above formula, R ₁ represents a hydrogen atom or a methyl group, and A ₁ is Represents, R ₂ , R ₃ , R ₄ and R ₅ may be the same or different, each represents an alkyl group optionally having a substituent, an aryl group or an aralkyl group, n represents 0, 1 or 2, B represents an alkylene group which may have an ester bond, an arylene group or an aralkylene group,
R ₆ represents a hydrogen atom or an alkyl group] or more than 20% by weight of the anionic monomer or 80% by weight of at least one monomer copolymerizable therewith
A synthetic resin molded article having excellent antistatic properties, characterized in that an antistatic polymer film formed by polymerizing a monomer mixture comprising: 2. The monomer copolymerizable with the anionic monomer is represented by the general formula (II): (In the above formula, R ₇ represents a hydrogen atom or a methyl group, R ₈ represents a hydrogen atom, an alkyl group having no copolymerizable functional group having 1 to 18 carbon atoms, an aralkyl group or an aryl group; And m represents an integer of 0 to 500) and / or a compound having two or more copolymerizable unsaturated double bonds. 1
The molded article as described. 3. A compound of the general formula (I) (In the above formula, R ₁ represents a hydrogen atom or a methyl group, and A ₁ is Represents, R ₂ , R ₃ , R ₄ and R ₅ may be the same or different, each represents an alkyl group optionally having a substituent, an aryl group or an aralkyl group, n represents 0, 1 or 2, B represents an alkylene group which may have an ester bond, an arylene group or an aralkylene group,
R ₆ represents a hydrogen atom or an alkyl group] or more than 20% by weight of the anionic monomer or 80% by weight of at least one monomer copolymerizable therewith
After forming a film of an antistatic polymer obtained by polymerizing a monomer mixture consisting of the following on the surface of at least one mold of a pair of molds, a raw material of a synthetic resin as a base material is formed on the mold. A method for producing a synthetic resin molded article having excellent antistatic properties, comprising injecting and polymerizing to transfer the film from the mold surface to the substrate surface, and then removing the molded article from the mold. 4. The monomer copolymerizable with the anionic monomer is represented by the general formula (II): (In the above formula, R ₇ represents a hydrogen atom or a methyl group, R ₈ represents a hydrogen atom, an alkyl group having no copolymerizable functional group having 1 to 18 carbon atoms, an aralkyl group or an aryl group; And m represents an integer of 0 to 500) and / or a compound having two or more copolymerizable unsaturated double bonds. 3
The described method. 5. A monomer mixture of 50% by weight or more of methyl methacrylate or methyl methacrylate and 50% by weight or less of a monomer copolymerizable therewith, or a mixture thereof with a partial polymer thereof. 4. The method according to claim 3, wherein the coating is applied to the surface of the mold in the form of a film. 6. The mold according to claim 3, wherein the mold comprises two stainless steel endless belts and a gasket, which are mirror-polished on one side and travel in the same direction and at the same speed.
The described method.