JPH01101150A - Antistatic method for synthetic resin holding - Google Patents

Abstract

PURPOSE:To obtain continuous antistatic effect at low cost by forming a layer of an electro-conductive copolymer composition of a specific vinyl chloride type on the surface of a synthetic resin molding. CONSTITUTION:A layer of a vinyl chloride-type electro-conductive copolymer composition which is prepared by adding a metal salt with a vinyl chloride copolymer having a unit of vinyl chloride and a unit of polyalkyleneoxide (meth) acrylate ester represented by formula I is formal on the surface of a synthetic resin molding. The vinyl chloride unit in the vinyl chloride copolymer unit is in the range of 60-96wt.%, polyalkyleneoxide (meth) acrylate unit is contained in the range of 4-40wt.%, the average degree of polymerization is in the range of 200-1500. The metal salt is an alkali metal salt, which is contained in the range of 1-15wt.%. In the formula, R1 is a hydrogen atom, or a methyl group, R2 is a polyoxialkylene group having a degree of polymerization of 2-23, X is an hydrogen atom, or an aliphatic or aromatic hydrocarbon having 1-6 carbon atoms.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for preventing static electricity on a synthetic resin molded article.

(Prior art) Synthetic resins such as vinyl chloride resins are inexpensive, have good moldability, and have excellent properties, so they can be used for various molded products,
Widely used as sheets and films. However, synthetic resin molded bodies such as vinyl chloride resins are easily charged with electricity, which causes various problems.

In order to prevent such charging, attempts have been made to impart electrical conductivity to synthetic resin molded bodies.

As the synthetic resin molded body having conductivity, surfactants,
There are synthetic resin molded bodies blended with carbon black, metal powder, conductive fibers, etc., and synthetic resin molded bodies whose surface is coated with a surfactant.

However, the surfactant blended or coated tends to bleed from the molded product or fall off the surface of the molded product, so the antistatic effect cannot be sustained. Blends of carbon black, metal powder, conductive fibers, etc. maintain the antistatic effect, but in order to obtain the desired conductivity, it is necessary to add a large amount of these conductive substances.

Therefore, it is expensive.

There are also synthetic resin molded bodies with noble metals or metal oxides attached to their surfaces by vapor deposition, sputtering, or the like. Although such molded bodies have excellent antistatic effects, they are expensive and have low productivity.

To solve these drawbacks, carbon black,
There is a synthetic resin molded body whose surface is coated with a conductive paint made by dispersing a conductive substance such as metal powder in a resin solution. Although this molded product is inexpensive and exhibits excellent antistatic effects, the conductive material is different from the resin, so
As expected, it bleeds and falls off easily.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional problems, and its purpose is to provide a synthetic resin molded article that is inexpensive and can provide a long-lasting antistatic effect. The object of the present invention is to provide a method for preventing static electricity.

(Means for Solving the Problems) The present invention includes a specific monomer unit having conductivity as a copolymer component in the skeleton of a vinyl chloride polymer on the surface of a synthetic resin molded article, and furthermore, this monomer This was completed based on the inventor's knowledge that by forming a coating layer of a composition containing a metal salt that is thought to form a complex with the unit, there is no bleeding or shedding (the antistatic property can be significantly improved). It was done.

The method for preventing static electricity of a synthetic resin molded article of the present invention is based on a vinyl chloride system having a vinyl chloride unit and a (meth)acrylic acid polyalkylene oxide ester unit represented by the following formula (I) on the surface of a synthetic resin molded article. The method is characterized by forming a layer of a vinyl chloride conductive copolymer composition in which the copolymer contains a metal salt, thereby achieving the above object.

Formula (I) RI (wherein RI is a hydrogen atom or a methyl group, Rt is a polyoxyalkylene group with a degree of polymerization of 2 to 23, X is a hydrogen atom,
Or it is an aliphatic or aromatic hydrocarbon group having 1 to 6 carbon atoms. ) In the vinyl chloride copolymer used in the present invention, the vinyl chloride unit generally contains 60
It is contained as a copolymer component in a range of 96% by weight, preferably 75% to 95% by weight. When it falls below 60% by weight,
Good properties as a vinyl chloride copolymer deteriorate.

When it exceeds 96%, it is difficult to obtain the desired antistatic properties.

In addition, the (meth)acrylic acid polyalkylene oxide ester unit generally contains 4 to 40% by weight in the copolymer,
It is preferably contained as a copolymerization component in a range of 5 to 25% by weight. If it is less than 4% by weight, the desired antistatic properties cannot be obtained.

If it exceeds 40% by weight, although the antistatic properties will be good, the solubility in organic solvents will decrease due to increased hydrophilicity, which is not preferable when a solution coating method is employed as a layer forming method.

Examples of the (meth)acrylic acid polyalkylene oxide ester include polypropylene glycol methacrylate, polyethylene glycol methacrylate, polyethylene glycol polypropylene glycol methacrylate, polyethylene glycol polybutylene glycol methacrylate, polyethylene glycol polytetramethylene glycol monomethacrylate, methoxy polyethylene glycol methacrylate, methoxy At least one of polyethylene glycol acrylate, phenoxypolyethylene glycol acrylate, butoxydiethylene glycol acrylate, etc. is used.

The average degree of polymerization of the above copolymer is in the range of 200 to 1,500, preferably 600 to 1,200. If it is less than 200, the strength of the coating layer will be low, and if it is more than 1,500, the solubility in organic solvents will decrease or the surface condition of the coating layer will deteriorate.

The vinyl chloride copolymer having the vinyl chloride unit and the (meth)acrylic acid polyalkylene oxide ester unit contains a metal salt to form a conductive copolymer composition. The introduction of this metal salt improves the antistatic properties of the vinyl chloride copolymer.

This metal salt is generally contained in the conductive or electrically conductive resin composition.
It is contained in an amount of 2% to 10% by weight. If it is less than 1% by weight, it is difficult to obtain the desired antistatic properties, and if it is more than 15% by weight, the metal salt will bleed, resulting in poor transparency.

As the above-mentioned metal salt, at least one of thiocyanate, phosphate, sulfate, halogen oxyacid, perhalogen oxyacid, tetrahalogen perborate, polyhalogenated organic strong acid salt, etc. is used. In particular, alkali metal salts such as lithium salts, sodium salts, and potassium salts of the above compounds are preferred. Such compounds include, for example, sodium thiocyanate and lithium perchlorate.

The vinyl chloride copolymer described above may contain other heptamer units copolymerizable with vinyl chloride as a copolymerization component within a range that does not impair antistatic properties. Examples of such monomers include olefins such as ethylene and propylene, and vinegar! Vinyl, vinyl esters such as vinyl propionate, non-functional (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and lauryl (meth)acrylate. There are acrylates and vinylidene chloride. Such monomer units are generally included to improve the Tg, viscosity, and solubility of the copolymer.

Any known polymerization method can be used to polymerize the above-mentioned vinyl chloride copolymer, such as emulsion polymerization method,
There are suspension polymerization methods, solution polymerization methods, and precipitation polymerization methods. As a medium for the precipitation polymerization method, lower alcohols, particularly methanol, are preferable because of their low cost.In the precipitation polymerization method, the copolymer is obtained as a fine powder, so that it can be easily molded.

The polymerization temperature is generally in the range of 35 to 70°C.

The vinyl chloride conductive copolymer composition used in the present invention has good solubility in organic solvents. Examples of soluble solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, ketones such as cyclohexanone, esters such as ethyl acetate and butyl acetate, salts such as ethylene dichloride and chloromethane, thread solvents, tetrahydrofuran, Polar solvents include dimethylformamide and dimethyl sulfoxide.

Therefore, in the present invention, a layer of the vinyl chloride conductive copolymer composition described above is formed on the surface of the synthetic resin molded article. The method for forming such a layer is to prepare a solution by dissolving the above-mentioned vinyl chloride-based conductive copolymer composition in the above-mentioned suitable organic solvent, and applying this solution by coating, spraying or dipping. A method of applying it to the surface of a synthetic resin molded article is preferred.

As the synthetic resin molded article, a synthetic resin molded article made of vinyl chloride resin, acrylic resin, styrene resin, polycarbonate, polyimide, polyetherimide, etc. has good adhesion with the vinyl chloride conductive copolymer composition. is good and suitable. Moreover, in the case of an olefin resin molded article such as polyethylene or polypropylene, the surface thereof is subjected to, for example, a corona discharge treatment to increase the wetting tension.

In the present invention, when a coating layer of the above-mentioned vinyl chloride conductive copolymer composition is formed on the surface of a vinyl chloride resin molded article, the molded article and the layer of the composition are firmly bonded and integrated. Therefore, this combination is optimal. In this case, the solvent for the composition is preferably a mixed solvent of methyl ethyl ketone/toluene/cyclohexanone.

In addition, as the vinyl chloride resin molded article, polyvinyl chloride resin, chlorinated polyvinyl chloride resin, vinyl chloride-ethylene copolymer resin, vinyl chloride-vinyl acetate copolymer resin,
Sheet-like molded products and irregularly shaped products made of vinyl chloride-acrylic acid ester copolymer resin, vinyl chloride-alkyl vinyl ether copolymer resin, vinyl chloride graft resin made by graft copolymerizing vinyl chloride onto ethylene-vinyl acetate copolymer resin, etc. There is a shaped body.

If the molded product is a sheet-like molded product, the solution of the composition described above is applied by surface coating using a roll coater, a doctor blade, or the like.

If the molded article is a shaped article, a solution of the above-mentioned composition is applied by spray coating or the molded article is immersed in the solution.

After applying the solution of the vinyl chloride type conductive copolymer composition to the surface of the synthetic resin molded body as described above, the solution is dried to remove the solvent, thereby applying the above-mentioned composition to the surface of the molded body. Layers of matter are formed. In the present invention, it is also possible to form a layer of the composition on the surface of the molded article by a melt extrusion coating method under appropriate conditions without using a solvent.

(Function) The conductive copolymer composition formed on the surface of the synthetic resin molded product contains a specific (meth) copolymer component of vinyl chloride.
Contains acrylic acid polyalkylene oxide ester units, and this copolymer component continuously forms a path through which metal salt ions can move well in the copolymer composition, thereby exhibiting good electrical conductivity. and exhibits excellent antistatic properties.

In addition, the metal salt contained in the above copolymer composition is thought to form a complex with the above copolymerization component, thereby preventing bleeding or reducing transparency, and furthermore, the metal salt contained in the above copolymer composition is Combined with the action of the ingredients, it maintains antistatic properties.

Furthermore, since the above copolymer composition has good solubility in various organic solvents, the solution can be easily prepared, and by selecting an appropriate organic solvent, it can be used with various synthetic resin molded articles. It is possible to form a layer of a conductive copolymer composition with good adhesion.

(Example) Examples and comparative examples of the present invention are shown below.

Example 1 Polyethylene glycol polytetramethylene glycol monomethacrylate (Blenmar 55PI! T-800, manufactured by NOF Corporation) was added to methanol as vinyl chloride and (meth)acrylic acid polyalkylene oxide ester of formula (I), and a catalyst was added. α-cumylperoxyneodecanoate was added as a solvent, and the mixture was polymerized at 43°C for 4 hours. After removing methanol by centrifugation, at 50°C.
A copolymer was obtained by vacuum drying for 24 hours.

The average degree of polymerization of the obtained copolymer was 1000, and the copolymer contained 72% by weight of vinyl chloride units and 28% by weight of polyethylene glycol polytetramethylene glycol monomethacrylate units.

This copolymer was dissolved in a mixed solvent of methyl ethyl ketone/toluene/cyclohexanone (weight ratio 1/1/4) to obtain a copolymer solution with a concentration of 16% by weight. A solution of the copolymer composition was prepared by adding and dissolving 3% by weight of lithium acetate to the above copolymer.

Using a doctor blade, apply this solution to a 2IIIll thick transparent hard vinyl chloride resin plate in 15 μm and 30 μm increments.
A layer of the conductive vinyl chloride copolymer composition was formed.

The surface resistivity, adhesion, transparency, and bleedability of this layer were measured as follows. The results of these measurements are shown in Table 1.

(I) Surface specific resistance value A hard vinyl chloride resin plate on which a layer of the above-mentioned conductive vinyl chloride copolymer composition was formed was left at 20°C and 165%RH for 24 hours and 1 month. M
The surface specific resistance value was measured using CP-TESTER (manufactured by Mitsubishi Yuka Co., Ltd.).

(2) Adhesion In the layer of the above-mentioned conductive vinyl chloride copolymer composition, dots are placed at intervals of 1 peg, a peel test is performed using cellophane tape, and the number of peeled out of the 100 dots is measured, This was used as a measure of adhesion.

(3) Transparency The transparent hard vinyl chloride plate on which the layer of the conductive vinyl chloride copolymer composition described above was formed was visually evaluated as good or poor in transparency.

(4) Bleeding property When a transparent hard vinyl chloride plate on which a layer of the above-mentioned conductive vinyl chloride copolymer composition is formed is left at room temperature, if cloudiness or precipitates are observed on the surface, it is considered to be defective. The case where the test was not performed was considered good.

Example 2 The same as Example 1 except that the vinyl chloride units in the copolymer were 90% by weight and the polyethylene glycol polytetramethylene glycol monomethacrylate units were 10% by weight. I did it in the same way.

Example 3 Example 1 except that the metal salt lithium trifluoroacetate was replaced with lithium perchlorate and the amount added to the copolymer was 4% by weight. I did it in the same way.

Comparative Example 1゜Example 1 except that polyethylene glycol polytetramethylene glycol monomethacrylate was not added. I did it in the same way.

Comparative Example λ Example 1 except that the metal salt lithium trifluoroacetate was not included. I did it in the same way.

(Margin below) (Effects of the Invention) According to the present invention, since a layer of the above-mentioned specific vinyl chloride conductive copolymer composition is formed on the surface of the synthetic resin molded product, the synthetic resin molded product Antistatic charge can be effectively and inexpensively prevented.

Moreover, the antistatic property of the molded article is maintained over a long period of time and has sustainability.

Patent! ! ! Odori application submission Ganjin Chemical Industry Co., Ltd. Representative Hiro 1) Kaoru

Claims (1)

[Claims] 1. A vinyl chloride copolymer having vinyl chloride units and (meth)acrylic acid polyalkylene oxide ester units represented by the following formula (I) is coated with metal on the surface of a synthetic resin molded body. A method for preventing static electricity on a synthetic resin molded article, which comprises forming a layer of a vinyl chloride conductive copolymer composition containing a salt. Formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R_1 is a hydrogen atom or a methyl group, R_2 is a polyoxyalkylene group with a degree of polymerization of 2 to 23, and X is a hydrogen atom or a 1 to 6 aliphatic or aromatic hydrocarbon groups.) 2. The vinyl chloride unit is 60 to 9 in the copolymer.
The method for preventing static electricity of a synthetic resin molded article according to claim 1, wherein the content is in the range of 6% by weight. 3. The method for preventing static electricity of a synthetic resin molded article according to claim 1, wherein the (meth)acrylic acid polyalkylene oxide ester unit is contained in the copolymer in an amount of 4 to 40% by weight. . 4. The method for preventing static electricity on a synthetic resin molded article according to claim 1, wherein the copolymer has an average degree of polymerization in the range of 200 to 1,500. 5. The method for preventing electrification of a synthetic resin molded article according to claim 1, wherein the metal salt is an alkali metal salt. 6. The method for preventing static electricity on a synthetic resin molded article according to claim 1, wherein the metal salt is contained in a range of 1 to 15% by weight. 7. A patent in which the metal salt is at least one of a thiocyanate, a phosphate, a sulfate, an oxyhalogen acid salt, an oxyhalogen acid salt, a tetrahalogenated borate, and a strong polyhalogenated organic acid salt. A method for preventing static electricity on a synthetic resin molded article according to claim 1. 8. The method for preventing static electricity on a synthetic resin molded article according to claim 1, wherein the synthetic resin molded article is a vinyl chloride resin molded article.