JPH09216961A - Antistatic thermoplastic resin plate or sheet, and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent uneven stretching in embossing of a conductive coating layer formed on a thermoplastic film bonded to a thermoplastic resin plate or sheet by thermally bonding the film having the conductive coating layer formed thereon to the plate or sheet and embossing the bonded thermoplastic resin film in a specified manner. SOLUTION: A thermoplastic resin film having a conductive coating layer formed thereon is thermally bonded to a thermoplastic resin plate or sheet with the coating layer kept outside and is embossed. The coating layer is formed from a conductive coating material contg. a usually used conductive powder selected from among org. and inorg. conductive powders. The resultant antistatic thermoplastic resin plate or sheet has a conductive coating layer uniformly stretched on the embossed surface; i.e., a conductive coating layer with little variation in thickness can be formed on the embossed surface. Thus obtd. plate or sheet can be used more widely as an industrial material, such as for a cover for a building material or an instrument in a clean room.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an antistatic thermoplastic resin plate or sheet and an antistatic thermoplastic resin plate or sheet obtained thereby.

[0002]

2. Description of the Related Art Building materials and other industrial materials based on a thermoplastic resin plate or sheet are widely used because of their excellent water resistance, corrosion resistance and chemical resistance. However, in spite of the many excellent properties described above, it has the property of being easily charged with static electricity due to slight air flow and contact friction with articles, so dust floating in the air adheres and contaminates the surface. It has a drawback that it does.

As a conventional antistatic measure for the thermoplastic resin plate or sheet, fine powder of metal such as aluminum or zinc, metal oxide such as titanium oxide, zinc oxide or tin oxide is formed on the surface of the thermoplastic resin plate or sheet. , A conductive carbon powder, a conductive polyaniline powder, or the like, a conductive substance is thinly and uniformly applied, or the conductive substance is homogeneously kneaded into a thermoplastic resin to obtain a conductive thermoplastic resin composition. Was molded by extrusion molding or injection molding to produce a conductive thermoplastic resin molded product.

However, the electrically conductive substance is uniformly kneaded in the thermoplastic resin, and a molded article obtained by extrusion molding or injection molding of the electrically conductive thermoplastic resin composition is highly antistatic. Then, a large amount of conductive material must be kneaded into the thermoplastic resin, and there is a problem that the mechanical strength of the resulting thermoplastic resin molded product is significantly reduced, and the thermoplastic resin plate or sheet Uniformly applying a highly antistatic conductive paint to the surface is disclosed, for example, in JP-A-59-177813.
Although the coating technology has been advanced to a certain level as disclosed in Japanese Unexamined Patent Application Publication No. 2004-135, the above highly antistatic conductive paint is uniformly applied to the surface of an embossed thermoplastic resin plate or sheet. It is extremely difficult to do.

That is, when the above-mentioned highly antistatic conductive paint is applied to the surface of the embossed thermoplastic resin plate or sheet by a usual coating device such as a roll coater, the protrusions on the embossed surface are formed. Only an extremely thin conductive coating film is formed, and conversely, the conductive coating material collects in the concave portion to form a convex lens-shaped coating film, and uniform antistatic performance cannot be imparted. When trying to solve the uneven conductive coating film on the surface of the embossed thermoplastic resin plate or sheet by increasing the thickness of the conductive coating film, the antistatic performance may be satisfied to some extent. However, not only does the conductive coating film become too thick and the surface properties of the thermoplastic resin plate or sheet deteriorate, but the conductive coating film itself becomes brittle.

Further, the conductive coating film is previously formed on the surface of the thermoplastic resin plate or sheet, and the thermoplastic resin plate or sheet on which the conductive coating film is formed is softened by heating to make the conductive film conductive. There is also a method to apply embossing from the surface of the conductive coating film, but the conductive coating film formed on the surface of the thermoplastic resin plate or sheet is unevenly stretched on the uneven surface such as an embossing roll and However, there is a drawback that the thickness varies.

The inventors of the present invention have made extensive studies as to a method for preventing uneven stretching of the conductive coating film during the embossing, and as a result, have found that the thermoplastic resin film compatible with the base thermoplastic resin plate or sheet. When the conductive coating film formed above is laminated on a base thermoplastic resin plate or sheet via the thermoplastic resin film and subjected to embossing, the conductive coating film is uniformly stretched and embossed. The inventors have found that a secondary variation in thickness does not occur due to processing, and have completed the present invention. or,
The conductive coating film of the antistatic thermoplastic resin plate or sheet obtained as described above has surface irregularities due to embossing together with the thermoplastic resin film laminated on the base thermoplastic resin plate or sheet. ,
As described above, since the conductive coating film is uniformly stretched, by heating and pressing the conductive coating surface,
The inventors have found that the surface of the conductive coating film can be easily smoothed without impairing the performance of the conductive coating film, and have completed the present invention.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above facts, and it is an object of the present invention to emboss by a coating method in which variations in the thickness of a conductive coating film are reduced. Another object of the present invention is to provide a method for producing an antistatic thermoplastic resin plate or sheet having a surface smoothed by applying heat or pressure to an embossed surface and an antistatic thermoplastic resin plate or sheet obtained thereby.

[0009]

According to the first aspect of the present invention,
An antistatic plastic characterized in that a thermoplastic resin film on which a conductive coating film is formed is heat-bonded to a base thermoplastic resin plate or sheet with the above-mentioned conductive coating film on the outside and embossed. The gist of the method is a plate or sheet manufacturing method.

The conductive paint forming the conductive coating film contains a thermoplastic resin and a conductive powder as its constituent components. The thermoplastic resin is not particularly limited as long as it has a coating film forming ability, for example, an acrylic resin,
Examples thereof include vinyl chloride resin, styrene resin, urethane resin and the like.

The above-mentioned conductive powder is not particularly limited as long as it is used for a conductive paint, and it is appropriately selected from inorganic conductive powder and organic conductive powder. Examples of the inorganic conductive powder include, for example, a conductive powder in which the surface of the particles or the whole particles is made of a tin oxide component, and the tin oxide component has an antimony oxide component of 0.1 to 20.
Conductive powder to which weight% is added. The electroconductive powder consisting of the tin oxide component shows high electroconductivity, but when the particle size is large, it scatters visible light, and the transparency of the electroconductive coating film obtained is reduced. If transparency or translucency is required, the particle size is preferably 0.4 μm or less. However, in the case of a conductive powder in which tin oxide is coated on the surface of particles having transparency such as barium sulfate, the scattering of the visible light is small, and thus the particle diameter may be 0.4 μm or more.

A conductive powder obtained by coating the surface of particles having transparency such as barium sulfate with antimony oxide-containing tin oxide is suitable for use as a transparent conductive coating film because of its high transparency. The particle diameter of the conductive powder obtained by coating the surface of barium sulfate particles with the above-mentioned tin oxide containing antimony oxide is suitably used in the range of 0.01 to 2 μm. When the particle diameter is less than 0.01 μm, the volume ratio of the barium sulfate particles, which is the core material, in the conductive coating film formed to have the necessary conductivity becomes small, Transparency decreases. Also, the above particle size is 2μ
When it exceeds m, the smoothness of the formed conductive coating film is deteriorated, minute air holes are generated between the filled conductive powders, the conductive coating film is clouded, and its transparency is deteriorated.

When the conductive coating film is required to have transparency, the content of the inorganic conductive powder is 100 to 100 parts by weight of the thermoplastic resin used as the binder.
500 parts by weight are preferred. When the amount is less than 100 parts by weight, the conductivity of the conductive coating film formed is reduced, and the required antistatic effect cannot be obtained. The resulting conductive coating film has reduced transparency.

As the organic conductive powder, for example,
Conductive powders such as an aniline polymer, a pyrrole polymer, and a thiophene polymer are exemplified. Above all, a conductive aniline polymer is preferably used because of its excellent thermal stability. The content of the conductive aniline-based polymer is preferably 0.1 to 30 parts by weight with respect to 100 parts by weight of the thermoplastic resin used as the binder. When the amount is less than 0.1 part by weight, the conductivity of the conductive coating film to be formed is reduced, the required antistatic effect is not obtained, and when the amount exceeds 30 parts by weight. As a result, the transparency of the formed conductive coating film decreases.

In addition to the thermoplastic resin and the conductive powder, an organic solvent, an ultraviolet absorber, an antioxidant, a thermal polymerization inhibitor, etc. may be added to the above-mentioned conductive paint, if necessary.

The organic solvent is appropriately selected and used depending on the type of the base thermoplastic resin plate or sheet to which the conductive paint is applied, the type of thermoplastic resin as the binder used, and the like, but the boiling point is 70 to 160. It is preferably about ° C. When the boiling point is less than 70 ° C, evaporation during coating is large, the viscosity of the conductive coating material changes, and the coating property is lowered, and when the boiling point exceeds 160 ° C, a large amount of energy is required for drying.

Examples of the organic solvent include cyclohexanone, ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (ethyl cellosolve), diethylene glycol dimethyl ether, butyl acetate, isopropyl acetone, methyl ethyl ketone, methyl isopropyl ketone, toluene, xylene. , Anisole and the like.

The UV absorber is not particularly limited, but examples thereof include salicylic acid UV absorbers, benzophenone UV absorbers, benzotriazole UV absorbers, and cyanoacrylate UV absorbers. . Examples of the antioxidant include a phenolic antioxidant, a phosphoric acid antioxidant, and a sulfur antioxidant. Examples of the thermal polymerization inhibitor include hydroquinone and p-methoxyphenol.

In order to improve the dispersibility of the electroconductive powder in the thermoplastic resin used as the binder, the electroconductive powder is previously treated with a silane coupling agent, a titanium coupling agent, an aluminate coupling agent, or the like. It is also effective to perform surface treatment before placing.

The method for preparing the conductive paint is not particularly limited, but it is prepared by mixing and dissolving the thermoplastic resin used as a binder and the conductive powder in an organic solvent. As a device for mixing and dissolving the plastic resin and the conductive powder in the organic solvent, for example, a sand mill, a ball mill, an attritor, a high-speed rotary stirring device, a triple roll or the like is used.

A photocurable resin may be used as the thermoplastic resin used as the binder of the conductive powder. The photocurable resin contains an organic polymer, a (meth) acrylate compound having at least two (meth) acryloyl groups in the molecule, and a photopolymerization initiator as constituent components. Examples of the organic polymer include α, β-
Those having an unsaturated ethylenic monomer as a constituent component are preferable, and examples of the α, β-unsaturated ethylenic monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene and α. -Styrene such as methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-hexylstyrene, pn-octylstyrene, p-methoxystyrene, p-phenylstyrene, and 3,4-dimethylchlorostyrene. , Vinylnaphthalenes such as α-vinylnaphthalene, ethylene, propylene, butylene, α-olefins having a carbon number of C5 to C30 or higher, vinyl halides such as vinyl chloride and vinyl bromide, vinyl acetate, propion Vinyl esters such as vinyl acrylate and vinyl butyrate, methyl (meth) acrylate,
Propyl (meth) acrylate, n- (meth) acrylate
Butyl, isobutyl (meth) acrylate, n-octyl (meth) acrylate, lauryl (meth) acrylate,
2-Ethylhexyl (meth) acrylate, 2-chloroethyl (meth) acrylate, methyl α-chloro (meth) acrylate, phenyl (meth) acrylate, (meth)
(Meth) acrylic acid esters such as dimethylaminoethyl acrylate, vinyl ethers such as vinyl methyl ether and vinyl ethyl ether, vinyl ketones such as vinyl methyl ketone and vinyl ethyl ketone, N-vinyl pyrrole, N-vinyl indole and the like. N-vinyl compound,
Examples thereof include (meth) acrylonitrile and (meth) acrylic acid amides. These α, β-unsaturated ethylenic monomers are used either as a single polymer or in combination of two or more as a copolymer.

The weight average molecular weight of the above organic polymer is 20,000 to 1,000,000, more preferably 50,000 to 500,000. When the weight average molecular weight is less than 20,000, the photopolymerizable resin composition containing the organic high molecular polymer is wound into a roll with a thermoplastic resin film having a conductive coating film of the present invention formed thereon. Although it may be rotated and temporarily stored, in such a case, cold flow occurs, and wrinkles and the like are formed in the adhesive layer made of the photopolymerizable resin composition, which makes it unusable. If the weight average molecular weight exceeds 1,000,000,
The solution viscosity of the photopolymerizable resin composition at the time of coating increases, and coating unevenness easily occurs.

The above-mentioned (meth) acrylate compound has at least two (meth) acryloyl groups in the molecule, and it is preferable that the polymerization is initiated by active rays such as ultraviolet rays or visible rays. Ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, nonaethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, Tripropylene di (meth) acrylate, tetrapropylene di (meth) acrylate, nonapropylene di (meth) acrylate, polypropylene di (meth) acrylate, pentaerythritol tri (meth) acrylate, Pentaerythritol penta (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, trimethylolpropane tri (meth) acrylate, glycerol tri (meth) acrylate, tris- (2-hydroxyethyl) -Isocyanuric acid ester (meth) acrylate, 2,2-bis [4
-(Acryloxydiethoxy) phenyl] propane,
2,2-bis [4- (methacryloxydiethoxy) phenyl] propane, 3-phenoxy-2-propanoyl acrylate, 1,6-bis (3-acryloxy-2-hydroxypropyl) -hexyl ether, tetramethylolmethane Tetra (meth) acrylate etc. are mentioned.

The amount of the (meth) acrylate compound added is preferably 10 to 250 parts by weight, more preferably 30 to 200 parts by weight, based on 100 parts by weight of the organic polymer. If the addition amount is less than 10 parts by weight, the surface hardness of the photocurable resin cured product containing the above components after irradiation with actinic rays such as ultraviolet rays is insufficient, and the addition amount exceeds 250 parts by weight. If the amount is too large, the surface of the cured product of the photocurable resin will be cracked or the adhesiveness will be insufficient, resulting in insufficient adhesion to the thermoplastic resin plate or sheet as the base material.

The photopolymerization initiator is not particularly limited as long as it has a property of initiating the polymerization of the (meth) acrylate compound by an actinic ray such as an ultraviolet ray or a visible ray. As an initiator,
For example, sulfides such as sodium methyl dithiocarbamate sulfide, tetramethyl thiuram monosulfide, diphenyl monosulfide, dibenzothiazoyl monosulfide and dibenzothiazoyl disulfide, thioxanthone, ethylthioxanthone, 2
Thioxanthones such as chlorothioxanthone, diethylthioxanthone and diisopropylthioxanthone, hydrazones, diazo compounds such as azoisobutyronitrile and benzenediazonium, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzophenone, dimethylaminobenzophenone, Michler's ketone , Aromatic carbonyl compounds such as benzylanthraquinone, t-butylanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-aminoanthraquinone, 2-chloroanthraquinone, benzyldimethylketal and methylphenylglyoxylate, 1-hydroxycyclohexylphenyl Ketone, 2-hydroxy-2-methyl-1-phenylpropane-1- Emissions, 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, 2,2-diethoxyacetophenone, 2,2-dimethoxy acetophenone derivatives such as acetophenone, 4-
Methyl dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, butyl 4-dimethylaminobenzoate, 4
-Dialkylaminobenzoic acid esters such as isopropyl diethylaminobenzoate, benzoyl peroxide, di-t-butyl peroxide, dicumyl peroxide, peroxides such as cumene hydroperoxide, 9-phenylacridine, 9-p- Acridine derivatives such as methoxyphenylacridine, 9-acetylaminoacridine, benzacridine, 9,10-dimethylbenzphenazine, 9-methylbenzphenazine, 10
-Phenazine derivatives such as methoxybenzphenazine,
Quinoxaline derivatives such as 4,4 ′, 4 ″ -trimethoxy-2,3-diphenylquinoxaline, 2,4,5-triphenylimidazoyl dimers, halogenated ketones, acylphosphine oxides, acylphosphonates and other acyls Examples thereof include phosphorus compounds.

Examples of visible light polymerization initiators include 2-nitrofluorene, 2,4,6-tris (trichloromethyl) -1,3,5-triazine and 3,3'-.
Carbonyl biscoumarin, thiomichler ketone, etc. are mentioned. To the photocurable resin composition, a non-volatile aliphatic amine or aromatic amine such as triethanolamine or methyldiethanolamine is added in order to prevent sensitivity deterioration due to oxygen inhibition of the photopolymerization initiator. May be. Further, among the above-mentioned photopolymerization initiators, dialkylaminobenzoic acid ester, Michler's ketone and the like have an effect of preventing sensitivity reduction due to oxygen inhibition of the photopolymerization initiator.

The amount of the photopolymerization initiator added is preferably 0.01 to 1 with respect to 100 parts by weight of the organic polymer.
It is 0 part by weight, more preferably 0.05 to 8 parts by weight.
If the amount added is less than 0.01 part by weight, the coating film obtained will be insufficiently cured even if the amount of actinic radiation such as ultraviolet rays is sufficient, and the binder cannot function. Further, even if the addition amount exceeds 10 parts by weight and becomes large, the photopolymerization rate is saturated and does not reach a rate higher than that, rather, the photocurable resin cured product is yellowed,
It also reduces optical properties such as total light transmittance and haze.

As the thermoplastic resin film on which the above-mentioned conductive coating film is formed, when the above-mentioned photocurable resin is used as the binder of the conductive paint, the irradiation efficiency is remarkably lowered upon irradiation with actinic rays such as ultraviolet rays. It is not particularly limited as long as it does not cause it, and may be compatible with the base thermoplastic resin plate or sheet, for example, a polyolefin film such as polyethylene or polypropylene, an acrylic resin. Examples thereof include films and polyester films such as polyethylene terephthalate.

The thermoplastic resin film may be uniaxially or biaxially stretched, or may be surface-released if necessary.
The thickness of the thermoplastic resin film is appropriately selected depending on the type of the thermoplastic resin used, the presence or absence of stretching treatment, etc., but about 10 to 200 μm is preferably adopted. When the thickness of the thermoplastic resin film is less than 10 μm,
When the conductive coating film formed on the thermoplastic resin film is heat-bonded to the base thermoplastic resin plate or sheet and embossed, the conductive coating film is rolled unevenly, The antistatic performance of the resulting embossed antistatic thermoplastic resin plate or sheet varies, and the initial antistatic effect cannot be obtained. or,
When the thickness of the thermoplastic resin film exceeds 200 μm, the thermoplastic resin film together with the conductive coating film,
Although it is heat-bonded to the base thermoplastic resin plate or sheet and embossed, sharp embossing is difficult to achieve.

The conductive paint is applied onto the thermoplastic resin film, and the coating method is not particularly limited as long as it is a method capable of precise coating, and for example, a spray method, The bar coating method, the doctor blade method, the roll coating method, the dipping method and the like can be mentioned.

The conductive layer formed on the thermoplastic resin film preferably has a thickness of 0.5 to 5 μm. If the thickness of the conductive layer is less than 0.5 μm, the conductivity becomes insufficient, and the required antistatic effect cannot be obtained. On the other hand, when the thickness of the conductive layer exceeds 5 μm, the total light transmittance decreases and the transparency decreases.

The above-mentioned base material thermoplastic resin plate or sheet is not particularly limited, but for example, vinyl chloride (PVC) resin, acrylic resin, A
BS (acrylonitrile-butadiene-styrene) resin, polycarbonate (PC) resin, polyethylene terephthalate resin, polyether ether ketone (PEE)
Examples thereof include plates and sheets molded from plastics such as K) resin, polyphenylene sulfide (PPS) resin, polyether sulfone (PES) resin, polysulfone resin, polyimide resin, polyetherimide resin, and fluororesin.

When a photo-curable resin is used as the thermoplastic resin used as the binder of the conductive powder, the light source of actinic rays such as ultraviolet rays used for curing the conductive paint is, for example, high pressure. Mercury lamp, halogen lamp, xenon lamp, nitrogen laser, He-C
A d laser, an Ar laser or the like is used.

The device for applying the above embossing is not particularly limited, but for example, as shown in FIG. 1, the surface of the embossing roll 32 and the embossing roll 32 embossed as uniformly as possible. An embossing device including a silicon rubber-clad pressure roll 31 pressed against a constant pressure 32 may be used. The embossing roll 32
The embossing depth is set according to the required quality of the final product, but is generally about 20 to 100 μm.
In the pressing roll 31, the thermoplastic resin film 52 on which the conductive coating film 51 to be pressed is formed is
Although it is cooled so as not to adhere to the surface of 1, the surface temperature of the substrate 1 is the thermoplastic resin plate or sheet 5
It is appropriately set depending on the three types, and is generally 70 to 130.
About ℃ is adopted. The embossing pressure of the embossing device 3 is appropriately set depending on the scale of the embossing device 3 used and the like, but a linear pressure of about 20 kg / cm is preferably used.

The thermoplastic resin film 52 on which the conductive coating film 51 is formed is heat-bonded and embossed to the base thermoplastic resin plate or sheet 53. The heat-bonding and embossing are performed. The process is, for example,
As shown in FIG. 1, when the extruded base material thermoplastic resin plate or sheet 53 is sandwiched and transferred by the embossing device 3 including the embossing roll 32 and the pressing roll 31, the surface of the embossing roll 32 is electrically conductive. Coating 51
May be supplied continuously so that they contact each other, or,
The thermoplastic resin film 52 is laminated with the conductive coating film 51 on the outside on the base material thermoplastic resin plate or sheet 53 that has been once formed, and the thermoplastic resin film 52 is thermocompression-bonded using, for example, a heat press device and the above-mentioned conductivity is obtained. The surface of the coating film 51 may be embossed.

Since the method for producing an antistatic thermoplastic resin plate or sheet according to the first aspect of the present invention is configured as described above, the conductive coating film on the embossed surface is uniformly stretched and embossed. A conductive coating film 51 having a small thickness variation can be formed on the surface of the formed thermoplastic resin plate or sheet 53.

Further, the thermoplastic resin film 5 for preventing uneven stretching of the conductive coating film 51 during embossing.
2 is laminated with the base thermoplastic resin plate or sheet 53 to form a composite, and, for example, as shown in the examples, the practicality of the hard vinyl chloride resin plate is combined with the weather resistance improving function of the acrylic resin laminate film, Demonstrate new performance.

According to a second aspect of the invention, the embossed conductive coating film surface of the antistatic thermoplastic resin plate or sheet obtained by the method of the first aspect is heated and pressed to make it smooth. The gist is a method for producing an antistatic thermoplastic resin plate or sheet characterized by the above.

Means for smoothing the surface of the embossed conductive coating 51 of the antistatic thermoplastic resin plate or sheet 5 by heating and pressing is not particularly limited, but for example, FIG. As shown in FIG. 5, the pressure roller 6 may be passed between the pair of heated pressure rollers 6, but may be heated and pressurized by using a heat press device or the like. When the surface of the conductive coating film 51 of the antistatic thermoplastic resin plate or sheet 5 thus embossed is heated and pressed,
As shown in FIG. 4, the electroconductive coating film 51 on the surface is rolled almost uniformly, the thickness of the electroconductive coating film 51 varies little, and the smooth surface 54 is formed without impairing the antistatic function. To be done.

Further, the conductive coating film 51 of the antistatic thermoplastic resin plate or sheet 5 obtained by the method of claim 1 has a base thermoplastic resin plate or sheet 53 as shown in an enlarged view in FIG. Although there is unevenness on the surface due to embossing together with the thermoplastic resin film 52 laminated on the above, since the conductive coating film 51 is uniformly stretched as described above, the conductive coating film as described above is formed. It is presumed that by heating and pressing the surface of 51, the surface can be made smooth 54 easily without impairing the performance of the conductive coating film.

The function obtained by the embossing is the same as described in the invention of claim 1, and for example, the cover 9 of the fluorescent lamp shown in FIGS. 5 to 7 or the lamp shown in FIG. Like the shade 10, the transparent patterns 8, 8, ... Are provided so that the embossing of a specific pattern such as a rhombus or a circle can be seen through the laminated interface between the base material thermoplastic resin plate or sheet 53 and the thermoplastic resin film 52. It may be provided. The above-mentioned two examples are flat plates and are manufactured by processing an antistatic thermoplastic resin plate or sheet 5 '. Alternatively, even if deep drawing is performed by vacuum forming or hot press forming, A three-dimensional molded body of an antistatic thermoplastic resin having a smooth surface 54 can be processed without impairing the function of the conductive coating film 51.

For comparison, FIGS. 9 and 10 show a conventional embossed antistatic thermoplastic resin plate or sheet that does not use a thermoplastic resin film (conductive coating 51 and thermoplastic resin plate or sheet). The surface condition of the conductive coating film before (A) and after (B) deep drawing of a molded product obtained by deep drawing is shown in a simulated sectional view of the antistatic thermoplastic resin plate. . FIG.
As can be seen from FIG. 10 and FIG. 10, the conductive coating film of the conventional embossed antistatic thermoplastic resin plate or sheet has already been thickly formed by uneven stretching or coating before deep drawing (A). Although there is a large variation (A), the conductive coating film 51 having a large variation in thickness undergoes non-uniform stretching during deep drawing, so the conductive coating film 5 is formed.
The variation in the thickness of 1 becomes larger and larger, and in an extreme case, a part of the conductive coating film 51 is broken and the surface of the base thermoplastic resin plate or sheet 53 is exposed on the surface of the conductive coating film 51. Then, the performance of the conductive coating film 51 is significantly reduced.

The above-mentioned state is used as the property of the conductive coating film 51.
Seen from Noh, it is shown in Examples and Comparative Examples described later.
So that the surface resistivity is 10⁶-10⁷Ω / □ antistatic
Approximately 4 times using thermoplastic resin plate or sheet
In the case of deep drawing, the method of the invention according to claim 2
Obtained when deep heating is used to apply heat and pressure.
The surface resistivity of deep-drawn products is 10⁸-10⁹Ω / □
And while maintaining a sufficient antistatic function,
The above-mentioned conventional embossed antistatic thermoplastic resin
The surface hardness of the molded product obtained by deep drawing a plate or sheet.
Resistive value is 10 ¹⁴Ω / □ or higher
The electricity prevention function is lost.

Since the method for producing the antistatic thermoplastic resin plate or sheet according to the second aspect of the present invention is configured as described above, the conductive coating film on the embossed surface is evenly spread to form the thermoplastic resin. It is possible to form a smooth conductive coating film having a small thickness variation on the surface of a plate or sheet.

The invention according to claim 3 has as its gist an antistatic thermoplastic resin plate or sheet obtained by the method according to claim 1 or claim 2. In the antistatic thermoplastic resin plate or sheet according to the third aspect of the present invention, as described above, a conductive coating film having a uniform thickness is formed on the antistatic thermoplastic resin plate or sheet through the thermoplastic resin film. In addition, since the layers are firmly laminated, high antistatic performance can be maintained for a long time.

[0046]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of 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.

(Example 1) [Preparation of electrically conductive coating] Copolymer resin for binder comprising 10 mol% of 2-hydroxypropyl acrylate and 90 mol% of vinyl chloride (manufactured by Sekisui Chemical Co., Ltd., trade name: S-REC E-HA). 100 parts by weight, methyl ethyl ketone 200
Parts by weight and 800 parts by weight of cyclohexanone are placed in an attritor and stirred to dissolve. Next, the primary particle size is 0.0
300 parts by weight of 2 μm tin oxide powder containing antimony oxide (manufactured by Mitsubishi Materials Corp., trade name: T-1) was added with stirring and dispersed by stirring for 8 hours to prepare a conductive paint.

A conductive coating material was applied to a 25 μm thick acrylic resin laminating film (trade name: Acryprene, manufactured by Mitsubishi Rayon Co., Ltd.) using a bar coater so that the film thickness after drying was 2 μm, and dried. A conductive coating film was formed into a long length and wound into a roll. Next, a hard vinyl chloride resin plate 53 having a thickness of 3 mm extruded from the mold 2 of the extrusion molding machine 1 shown in FIG. 1 is pressed by a pressing roll 31 whose surface temperature is kept at 90 ° C. and sandblasted to an emboss depth of 50 μm. The conductive coating film 5 when being sandwiched by the embossing device 3 composed of the embossing roll 32 and transferred.
1. The acrylic resin laminating film 52, which is formed into a roll shape and is wound in a roll, is prepared from the unroll stand 4 so that the conductive coating film 51 is in contact with the embossing roll surface of the hard vinyl chloride resin. It is supplied between the plate 53 and the embossing roll 32 and is pinched between the pressing roll 31 and the embossing roll 32, and as shown in the enlarged sectional view of FIG. 2, a conductive coating film 51, an acrylic resin laminate film 52, and The hard vinyl chloride resin plates 53 are laminated and heat-bonded in order, and the conductive coating film 51 is formed.
From the hard vinyl chloride resin plate 53 to the surface layer portion, the antistatic hard vinyl chloride resin plate 5 with the embossing was produced.

(Example 2) The antistatic hard vinyl chloride resin plate 5 obtained in Example 1 was maintained at a surface temperature of 80 ° C following the process of Example 1 as shown in FIG. Is passed between the heating and pressing rolls 6 having a pair of smooth surfaces to smooth the surface of the embossed conductive coating film 51 of the antistatic hard vinyl chloride resin plate 5 and to cool it. After cooling at 7, an antistatic hard vinyl chloride resin plate 5 ′ having a conductive coating film 54 with a smooth surface was prepared as shown in the enlarged sectional view of FIG.

(Example 3) A film having a thickness of 3 μm after drying an electrically conductive coating on a 100 μm thick acrylic resin laminating film (Mitsubishi Rayon Co., Ltd., trade name: Acryprene) 52 using a bar coater. As described above, a conductive coating film 51 was formed into a long length by coating and drying, a diamond-shaped embossing roll 32 having an embossing depth of 75 μm was used, and a hard acrylic modified vinyl chloride resin plate 53 having a thickness of 3 mm was used. An antistatic hard acrylic modified vinyl chloride resin plate 5 ′ having a conductive coating film 54 with a smooth surface was produced as shown in the enlarged sectional views of FIGS. 5 and 6 in the same manner as in Example 2 except that it was used. . The obtained antistatic hard acrylic modified vinyl chloride resin plate 5'is processed,
A fluorescent lamp cover 9 as shown in FIG. 7 was produced.

(Example 4) A 250 μm-thick acrylic resin laminating film (made by Mitsubishi Rayon Co., Ltd., trade name: Acryprene) 52 was coated with a conductive paint using a bar coater to give a film thickness of 3 μm after drying. Was applied and dried to form a long conductive coating film 51, an embossing roll 32 having an embossing depth of 100 μm was used, and a hard acrylic modified vinyl chloride resin plate 53 having a thickness of 3 mm was used. Except for the above, in the same manner as in Example 2, an antistatic hard acrylic modified vinyl chloride resin plate 5 ′ having a conductive coating film 54 having a smooth surface was produced. The obtained antistatic hard acrylic modified vinyl chloride resin plate 5 ',
A vacuum forming machine was used to perform deep drawing four times as deep as the conductive coating film 54 on the outside to form an antistatic hollow truncated cone shaped product.

Comparative Example 1 A polyethylene terephthalate film obtained by subjecting the conductive paint of Example 1 to a release treatment (hereinafter
A conductive coating film was formed on the PET film in the same manner as in Example 1 except that the conductive film was applied on the PET film. Then, the hard vinyl chloride resin plate 53 having a thickness of 3 mm is molded by the extruder 1 in the same manner as in Example 1, and the conductive film formed on the PET film is formed until the embossing device 3 in Example 1 is reached. Of the conductive coating film 51 onto the hard vinyl chloride resin plate, and then the conductive coating film 51 is brought into contact with the surface of the embossing roll 32, and the embossing pressure is also adjusted to be the same as in Example 1. Then, an embossed antistatic hard vinyl chloride resin plate (A) was produced.

COMPARATIVE EXAMPLE 2 Using the embossing device 3 used in Example 1, one surface of the hard vinyl chloride resin plate 53 having a thickness of 3 mm was embossed, and then the conductive paint of Example 1 was applied to the hard chloride. On the embossed surface of the vinyl resin plate 53, the bar coater used in Example 1 was applied so that the film thickness after drying would be 2 μm, and dried to emboss the antistatic hard vinyl chloride resin plate ( A)
Was prepared.

(Comparative Example 3) The surface of the conductive coating film 51 of the antistatic hard vinyl chloride resin plate obtained in Comparative Example 1 was
A pair of heating / pressurizing rolls 6 and 6 and a cooling roll 7 having a surface temperature of 80 ° C. used in Example 2 were used to carry out charging in the same manner as in Example 2 with a conductive coating film 54 having a smooth surface. An anti-hard vinyl chloride resin plate (A) was prepared.

(Comparative Example 4) The conductive coating film 51 formed on the embossed surface of the antistatic hard vinyl chloride resin plate obtained in Comparative Example 2 was used for the surface temperature in Example 2. Of the antistatic hard vinyl chloride resin plate (A) having a conductive coating film 54 having a smooth surface in the same manner as in Example 2 using a pair of heating / pressurizing rolls 6, 6 and cooling roll 7 held at 80 ° C. ) Was produced.

Comparative Example 5 The conductive coating film 51 formed on the embossed surface of the antistatic hard vinyl chloride resin plate obtained in Comparative Example 1 was used at the surface temperature of Example 2. Of the antistatic hard vinyl chloride resin plate (A) having a conductive coating film 54 having a smooth surface in the same manner as in Example 2 using a pair of heating / pressurizing rolls 6, 6 and cooling roll 7 held at 80 ° C. ) Was produced. The obtained antistatic hard vinyl chloride resin plate (A) was deep drawn four times by a vacuum forming machine so that the conductive coating film 54 was on the outside, and an antistatic hollow truncated cone shaped product (B ) Was molded.

(Comparative Example 6) A conductive coating film was formed on the embossed surface in the same manner as in Comparative Example 2 except that a hard acrylic modified vinyl chloride resin plate was used instead of the hard vinyl chloride resin plate. An antistatic hard vinyl chloride resin plate (A) having 51 was prepared. Obtained antistatic hard acrylic modified vinyl chloride resin plate (A)
Is subjected to deep drawing four times by a vacuum forming machine so that the conductive coating film 51 formed on the embossed surface is on the outside, and an antistatic hollow truncated cone shaped product (B)
Was molded.

In order to evaluate the performance of the antistatic hard vinyl chloride resin plates obtained in the above Examples and Comparative Examples, the surface resistivity and the adhesion of the conductive coating film were tested by the following methods. The evaluation results are shown in Table 1.

1. Surface resistivity: The surface resistivity was measured according to ASTM D257. Test piece 300 mm ×
For 300 mm, 10 measurement points were determined by the random sampling method. 2. Adhesion: In order to evaluate the adhesion between the conductive layer and the base plastic plate in accordance with JIS K 5400,
Make cuts in the conductive coating at intervals of 1 mm vertically and horizontally, 10
0 cross-cuts are made, and cellophane adhesive tape (manufactured by Sekisui Chemical Co., Ltd., trade name: Sekisui cellophane tape N
o. 252) was attached and peeled off, and a cross-cut peeling test was performed to count how many 100 conductive films of the cross-cut remained without peeling off.

[0060]

[Table 1]

As a result of the measurement, in the antistatic hard vinyl chloride resin plate of Example 1, the surface resistivity was 5 at all 10 points.
The sample had no variation of 6 × 10 ⁶ Ω / □ and showed high antistatic performance, whereas Comparative Example 1 had a surface resistivity of the same level but poor adhesion. Further, in Comparative Example 2, there is a large variation of 10 ⁹ to 10 ^11, and even if it is observed with the naked eye, the unevenness of the embossed surface has a shade of color, which is secondary due to the rolling of the conductive coating film accompanying the embossing. It shows that there are variations in the thickness of the conductive coating film and uneven coating of the conductive coating film. Also, the adhesiveness between the conductive coating film and the thermoplastic resin film or the base material thermoplastic resin plate or sheet may be due to the variation in the thickness of the conductive coating film. However, in the comparative example, the adhesiveness is lowered.

In addition, the antistatic hard vinyl chloride resin plates of Examples 2 and 3 showed a high antistatic performance with a surface resistivity of 10 ⁶ Ω / □ and had a small variation, but comparison was made. The antistatic hard vinyl chloride resin plates of Examples 3 to 4 had a surface specific resistance of 10 ⁹ to 10 ¹² Ω / □, which reduced the antistatic performance and significantly increased the variation, and the adhesion of the conductive coating film. The sex is also declining.

Further, in the antistatic hard vinyl chloride resin plate of Example 4, the conductive coating film laminated on the surface of the hard vinyl chloride resin plate is stretched largely as in deep drawing, but it is stretched uniformly. So the surface resistivity is 1
It exhibits high antistatic performance of 0 ⁸ to 10 ⁹ Ω / □, its variation is small, and it is firmly adhered to the hard vinyl chloride resin plate as the base material. On the other hand, in the antistatic hard vinyl chloride resin plates of Comparative Examples 5 and 6, the conductive coating film is stretched nonuniformly by deep drawing, and the state in the thickness direction is simulated in FIGS. 9 and 10. As shown in the cross-sectional view, there were spots where the surface resistivity was extremely high, and the variations were extremely large at 10 ¹² to 10 ¹⁵ Ω / □, and the antistatic performance was substantially lost. You can see that

[0064]

The method for producing an antistatic thermoplastic resin plate or sheet according to the first aspect of the present invention is configured as described above, so that the conductive coating film on the embossed surface is uniformly stretched to form an embossed surface. It is possible to form a conductive coating film having a small variation in thickness on the surface of a thermoplastic resin plate or sheet subjected to the treatment. Therefore, the embossed antistatic thermoplastic resin plate or sheet
Since it is possible to highly prevent the adhesion of dust due to electrification while maintaining the excellent water resistance, corrosion resistance, chemical resistance, etc. of thermoplastic resins, it can be used in industries such as building materials and equipment covers in clean rooms. As a material, it will further increase its demand.

Further, a thermoplastic resin film for preventing uneven stretching of the conductive coating film during embossing is laminated with a base thermoplastic resin plate or sheet to form a composite, which can be found in, for example, Examples. As described above, the practicability of the hard vinyl chloride resin plate is combined with the weather resistance improving function of the acrylic resin laminate film, and new effects are exhibited.

Since the method for producing an antistatic thermoplastic resin plate or sheet according to the second aspect of the present invention is configured as described above, the conductive coating film on the embossed surface is evenly spread to form the thermoplastic resin. It is possible to form a conductive coating film on the surface of a plate or a sheet that is smooth and heated and pressed and has a small variation in thickness of the conductive coating film by an extremely simple process.

As described above, the antistatic thermoplastic resin plate or sheet of the invention according to claim 3 obtained by the method for producing the antistatic thermoplastic resin plate or sheet of the invention according to claims 1 and 2 is excellently charged. As well as showing anti-static performance, it can hold the above performance for a long time with a strong adhesive force. It can be used in a wide range of antistatic fields, including decorative covers such as lamp covers and lamp shades.

[0068]

[Brief description of drawings]

FIG. 1 is an explanatory view for explaining a step of a method for producing an antistatic thermoplastic resin plate or sheet according to the first aspect of the invention.

FIG. 2 is a partially cutaway sectional view showing the antistatic thermoplastic resin plate or sheet of the invention of claim 3 obtained by the method for producing an antistatic thermoplastic resin plate or sheet of the invention of claim 1.

FIG. 3 is an explanatory diagram for explaining the steps of the method for producing an antistatic thermoplastic resin plate or sheet according to the second aspect of the invention.

FIG. 4 is a partially cutaway sectional view showing the antistatic thermoplastic resin plate or sheet of the invention of claim 3 obtained by the method for producing an antistatic thermoplastic resin plate or sheet of the invention of claim 2;

FIG. 5 is a partially cutaway cross section showing a product using the antistatic thermoplastic resin plate or sheet of the invention of claim 3 obtained by the method of manufacturing an antistatic thermoplastic resin plate or sheet of the invention of claim 2. It is a figure.

FIG. 6 is a sectional view taken along line VI-VI in FIG.

FIG. 7 is a partially cutaway perspective view showing a fluorescent lamp cover using the antistatic thermoplastic resin plate or sheet shown in FIGS. 5 and 6;

FIG. 8 is a partially cutaway perspective view showing a lamp shade using the antistatic thermoplastic resin plate or sheet according to the third aspect of the present invention.

9 is a partially cutaway cross-sectional view simulating the cross-sectional shape of the conductive coating film of the antistatic thermoplastic resin plate or sheet obtained in Comparative Example 1. FIG.

FIG. 10 is a partially cutaway cross-sectional view simulating the cross-sectional shape of the conductive coating film of the deep-drawn molded product obtained in Comparative Example 4.

[Explanation of symbols]

1 Extrusion Molding Machine 2 Mold 3 Embossing Device 31 Cooling Roll 32 Embossing Roll 4 Unroll Stand 5 Embossed Antistatic Thermoplastic Resin Plate or Sheet 5'Smooth Antistatic Thermoplastic Resin Plate or Sheet 51 Conductive Coating film 52 Thermoplastic resin film 53 Thermoplastic resin plate or sheet 54 Conductive coating film with smoothed surface 6 Heating / pressurizing roll 7 Cooling roll 8 Embossing pattern 9 Fluorescent lamp cover 10 Lamp shade A Obtained in Comparative Example 1 Cross-sectional shape of conductive coating film of antistatic thermoplastic resin plate or sheet (simulated diagram before deep-drawing molding) B Cross-sectional shape of conductive coating film of deep-drawing molded article obtained in Comparative Example 4 ( (Simulated drawing after deep drawing)

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display area B29K 101: 12 B29L 7:00

Claims (3)

[Claims] 1. A thermoplastic resin film on which a conductive coating film is formed is heat-bonded to a base thermoplastic resin plate or sheet with the conductive coating film facing outward, and embossed. And a method for producing an antistatic thermoplastic resin plate or sheet. 2. An antistatic property, characterized in that the embossed conductive coating film surface of the antistatic thermoplastic resin plate or sheet obtained by the method according to claim 1 is heated and pressed to be smoothed. Method for manufacturing thermoplastic resin plate or sheet. 3. An antistatic thermoplastic resin plate or sheet obtained by the method according to claim 1 or 2.