JPS62138244A - Antistatic laminated material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an antistatic plastic laminate that is transparent, vacuum-formable, and pressure-formable and has excellent antistatic performance and durability.

[Conventional technology]

Currently, plastic trays and other containers are often used for storing, transporting, storing, etc. electronic device parts and optical device parts. These plastic containers are easily charged with static electricity as they are, and on the other hand, the above-mentioned parts are easily damaged by static electricity, and are objects that extremely dislike the attachment of dust due to static electricity.

To this end, many proposals have been made to antistatically treat plastic trays and other containers, such as post-treating the surface with antistatic agents such as surfactants, or mixing conductive material powder into plastic sheets. method has been adopted.

In the former surface post-treatment method, the coated surfactant easily evaporates during long-term use or comes off due to g-rubbing, etc., and the method of applying antistatic paint, etc. If there are irregularities, it is difficult to apply uniformly, and the coating also increases the cost of the product.

In addition, in the latter method, conductive fine powder such as surfactant and carbon black is kneaded to form a conductive sheet, so it does not have the disadvantage of being easily desorbed as in the surface post-treatment method. In the kneading of surfactants, antistatic performance is generally not very good because the antistatic performance is exhibited by bleeding, and the latter method of kneading conductive powder has good antistatic performance, but The moldability of the material is poor, and the sheet becomes black or other opaque, and especially in the case of carbon black, the color bleeds, which is undesirable because it can stain the stored parts, the operator, and the workbench.

[Problem that the invention seeks to solve]

The object of the present invention is to provide an antistatic material as a plastic material that does not have the above-mentioned drawbacks, has high antistatic performance, is highly durable, and can easily produce transparent containers by vacuum forming or pressure forming. The purpose of the present invention is to provide a flexible laminated material.

[Means for solving problems]

That is, the present invention provides a copolymer containing as essential repeating units one or more ionically electrolytic monomers having an ethylenically unsaturated group and one or more polymerizable monomers having an ethylenically unsaturated group, and a plasticizer. The present invention relates to an antistatic laminate material that can be vacuum-formed or pressure-formed, and is formed by coating a plastic sheet with an antistatic composition capable of forming a conductive transparent polymer film consisting of the following.

Next, the present invention will be explained in detail.

As the plastic of the plastic sheet forming the base layer of the laminate material of the present invention, any transparent material that can be vacuum-formed or pressure-formed can be preferably used, and examples thereof include hard polyvinyl chloride, polypropylene, polystyrene, polycarbonate, etc. be able to.

The thickness of the plastic sheet is not particularly limited and is appropriately selected depending on the purpose. It can be any general value, usually 0.
It is about 2 to 1.0 mm.

The antistatic composition that becomes the antistatic coating layer of the laminate of the present invention comprises one or more ionic electrolytic monomers having an ethylenically unsaturated group and one or more polymerizable monomers having an ethylenically unsaturated group. It is composed of a copolymer containing 100% as an essential repeating unit and a plasticizer, and forms a transparent conductive polymer film.

The ratio of the ion electrolytic monomer to the polymerizable monomer in this composition is preferably in the range of 10:90 to 50:50. If the content of the ion electrolytic monomer is less than 10% by weight, the conductivity is poor, and if it is more than 50% by weight, the film becomes brittle (unpreferably).

The ion electrolytic monomer referred to in the present invention includes salts of quaternary ammonium group-containing monomers, salts of sulfonium group-containing monomers, salts of phosphonium group-containing monomers, and among others, quaternary ammonium group-containing monomers. salt,
For example, methacryloyloxyethyltrimethylammonium chloride, 2-hydroxy-3-methacryloyloxypropyltrimethylammonium chloride, etc. are preferably used.

Polymerizable monomers include vinyl acetate, styrene, alkyl acrylate, alkyl methacrylate, acrylonitrile, N-methylol or alkoxymethyl (meth)
Examples include acrylamide, (meth)acrylic acid, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl acrylate, dimethylamino-2-hydroxypropyl (meth)acrylate, glycidyl (meth)acrylate, (meth)acrylamide, etc. can.

The above-mentioned ion electrolytic monomers and polymerizable monomers may be used alone or in combination of two or more. Further, in addition to these monomers, a third copolymerizable monomer may be used in combination. Examples of these monomers include heptamers having 2 (IN or more) ethylenically unsaturated groups, such as ethylene glycol dimethacrylate.

As a polymerization initiator for the copolymerization reaction of these monomer mixtures, common radical catalysts such as benzoyl peroxide and abbisisobutyronitrile can be used. The copolymer may be produced by either emulsion polymerization or solution polymerization.

This composition can be applied as a solution using an organic solvent or as an aqueous emulsion, but the former solution-type coating liquid is preferred from the viewpoint of coating workability.

If the laminated material of the present invention cannot be easily subjected to vacuum forming, pressure forming, etc., its utility value will be halved, so good formability is an essential requirement. This is why it contains as an essential ingredient. Of course, even if a plasticizer is not included, the co-electropolymer itself can contain a large amount of internal plasticizing component to improve the moldability, but if the copolymer itself improves the moldability, This is not preferable because the coated laminate may become prone to blocking due to the appearance of tackiness, and it is preferable to impart moldability by external plasticization with a plasticizer.

Any plasticizer can be used as long as it does not impair transparency, and examples thereof include phthalic acid derivatives such as dibutyl phthalate and dioctyl phthalate.

The content of the plasticizer in the composition varies depending on the composition of the 7-mer component of the copolymer of the composition, but is preferably 20% by weight or less of the solid content of the copolymer, and particularly in the case of a plasticizer that easily migrates, Since there is a large amount of bleeding, the content is preferably 10% by weight or less.

The plasticizer may be added to the composition before polymerization,
It may be carried out during the polymerization or after the polymerization.

Various coating methods such as barcode, roll coating, curtain coating, and gravure printing can be used to apply the antistatic composition to the plastic sheet. It may be coated on. In that case, the plastic sheet may be subjected to physical or chemical treatment in advance to improve the coating properties and adhesion of the antistatic composition, thereby improving the performance of the coating film of the antistatic composition. The film may be overcoated as long as it does not damage the film.

〔Effect of the invention〕

The laminate material of the present invention has excellent antistatic performance and durability,
It is a plastic laminate material that is transparent and has excellent formability in vacuum forming, pressure forming, etc.

〔Example〕

Next, examples of the present invention and comparative examples will be shown. In the examples, parts and percentages are by weight.

Example 1 405 parts of methyl cellosolve and 194 parts of methanol were placed in a polymerization tank equipped with a reflux condenser, a thermometer, a stirrer, and a nitrogen introduction tube.
parts, 80 parts of methacryloyloxyethyltrimethylammonium chloride, 60 parts of styrene, 30 parts of methyl methacrylate, 20 parts of butyl acrylate, 1 part of acrylic acid
0 parts of benzoyl peroxide and 1 part of benzoyl peroxide were mixed, stirred and heated while introducing nitrogen, and a polymerization reaction was carried out at 80° C. for 5 hours. The obtained antistatic composition solution had a solid content concentration of 25% and a viscosity of 150 cps/25°C. 8 parts of a plasticizer dioctyl phthalate was added to this solution to obtain a plasticizer-containing antistatic composition.

A dry film of this plasticizer-containing antistatic composition was coated onto a 3 mm thick hard polyvinyl chloride sheet using a bar coater.
The antistatic laminated material was obtained by coating to a thickness of μm. This laminate sheet was set in a vacuum forming machine, heated for 22 seconds with a far-infrared heater, and then vacuum formed to obtain a molded product.

Table 1 shows the measurement results of the appearance and surface resistance value of the laminate before molding, the appearance of the molded product, the surface resistance value, and the electrostatic voltage decay rate.

Example 2 In a polymerization tank similar to Example 1, 405 parts of methyl cellosolve, 194 parts of methanol, 70 parts of methacryloyloxyethyltrimethylammonium chloride, 70 parts of methyl methacrylate, 40 parts of t-butyl methacrylate,
10 parts of butyl acrylate, 10 parts of acrylic acid, 8 parts of dibutyl phthalate, and 1 part of benzoyl peroxide were blended, and a polymerization reaction was carried out in the same manner as in Example 1.

The obtained plasticizer-containing antistatic composition solution had a solid content concentration of 25.7% and a viscosity of 200 cps'/25°C.

This plasticizer-containing antistatic composition was coated onto a 0.3 mm thick hard polyvinyl chloride sheet using a bar coater to give a dry film thickness of 5 μm to obtain an antistatic laminate.

This laminate sheet was set in a vacuum forming machine, heated with a far infrared heater for 25 seconds, and then vacuum formed to obtain a molded product. Table 1 shows the results of the appearance and surface resistance value of the laminate before molding, the appearance of the molded product, the surface resistance value, and the electrostatic voltage decay rate.

Comparative Example 1 The antistatic composition solution obtained in Example 1 was applied to a 0.3 mm thick hard polyvinyl chloride sheet using a percoater without adding a plasticizer so that the dry film thickness was 5 μm. An antistatic laminate material was obtained. This laminate sheet was set in a vacuum forming machine, heated with a far infrared heater for 25 seconds, and then vacuum formed to obtain a molded product. The appearance and surface resistance value of the laminated material before molding, the appearance and surface resistance value of the molded product,
The results of the static voltage decay rate are shown in Table 1.

Comparative Example 2 In a polymerization tank similar to Example 1, 405 parts of methyl cellosolve, 194 parts of methanol, 70 parts of methacryloyloxyethyltrimethylammonium chlorite, 60 parts of methyl methacrylate, 60 parts of butyl acrylate, parts of acrylic MIO, and 1 part of benzoyl peroxide were added. was blended and a polymerization reaction was carried out in the same manner as in Example 1. The solid content concentration of the obtained antistatic composition solution was 25%,
The viscosity was 160 cps/25°C.

This antistatic composition was coated onto a 0.3 mm thick hard polyvinyl chloride sheet using a bar coater to give a dry film thickness of 5 μm to obtain an antistatic laminate. Place this laminated material sheet into a vacuum forming machine and heat it with a far infrared heater.
After heating for 3 seconds, vacuum forming was performed to obtain a molded product. Table 1 shows the results of the appearance and surface resistance value of the laminate before molding, the appearance of the molded product, the surface resistance value, and the electrostatic voltage decay rate.

The adhesiveness of the coating films in these Examples and Comparative Examples had no problem except in Comparative Example 2.

The test was carried out at 5°C and 50% RH.

(2) Regarding the appearance, ◯ indicates good and × indicates poor appearance.

(3 voltage decay speed is 5TATICDECAY ME
TER was measured using a 25" C115% RH tester using an ETS newsletter, and expressed as the 0% attenuation rate (the week force required to attenuate to OV after applying ±5000V.

The static voltage decay rate is FED, TEST METHOD
STD, No.

The test was conducted in accordance with the test method specified in 10IC-4046.

The MIL-B-81705B standard specifies that the standard for antistatic performance is 2 seconds or less for the time it takes for 5000V to decay to Ov using the above measurement method.

In the results shown in Table 1, the appearance of the molded product of Comparative Example 2 is marked with an x because the transparent conductive polymer film formed on the plastic sheet cannot follow the elongation during vacuum forming. A crack has occurred in the.

From the results shown in Table 1, it is understood that containers such as trays formed using the antistatic laminate sheet of the present invention are excellent in both appearance and antistatic properties.

Claims (1)

[Claims] (1) Consisting of a copolymer whose essential repeating units are one or more ionic electrolytic monomers having an ethylenically unsaturated group and one or more polymerizable monomers having an ethylenically unsaturated group, and a plasticizer. An antistatic laminate material that can be vacuum-formed or pressure-formed by coating a plastic sheet with an antistatic composition capable of forming a conductive transparent polymer film.