JPH062395B2 - Antistatic method for synthetic resin moldings - Google Patents

Description

The present invention relates to an antistatic method for synthetic resin moldings.

(Prior Art) Synthetic resins such as vinyl chloride resins are inexpensive, have good moldability, and have excellent properties.
Widely used as sheets and films. However, synthetic resin moldings such as vinyl chloride resins are easily charged with electricity, which causes various obstacles.
In order to prevent such electrification, it has been attempted to impart conductivity to the synthetic resin molded body.

As the synthetic resin molding having conductivity, a surfactant,
There are synthetic resin moldings in which carbon black, metal powder, conductive fibers and the like are blended, and synthetic resin moldings whose surface is coated with a surfactant. However, those obtained by blending or applying the surfactant are likely to bleed from the molded body or fall off from the surface of the molded body, so that the antistatic effect is not maintained. A blend of carbon black, metal powder, conductive fibers, and the like maintains 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 becomes expensive.

In addition, there is a synthetic resin molded body having a noble metal or metal oxide attached to its surface by vapor deposition, sputtering, or the like. Although such a molded article has an excellent antistatic effect, it is expensive and has low productivity.

In order to solve such drawbacks, carbon black,
There is a synthetic resin molded body in which a conductive coating material obtained by dispersing a conductive material such as metal powder in a resin solution is applied to the surface thereof. Although this molded article is inexpensive and exhibits an excellent antistatic effect, the conductive material is heterogeneous with respect to the resin, so that it is liable to bleed or fall off.

(Problems to be Solved by the Invention) The present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a synthetic resin molded article that is inexpensive and can obtain a durable antistatic effect. An object is to provide an antistatic method.

(Means for Solving Problems) The present invention provides a vinyl chloride-allylamine copolymer having a vinyl chloride repeating structural unit and an allylamine or its Lewis acid salt repeating structural unit on the surface of a synthetic resin molding. Is formed, whereby the above-mentioned object is achieved.

In the vinyl chloride-allylamine-based copolymer used in the present invention, the vinyl chloride repeating structural unit is generally contained as a copolymer component in the copolymer in an amount of 50 to 95 mol%, preferably 50 to 97 mol%. It When it is less than 50 mol%, good properties as a vinyl chloride-based aggregate are deteriorated. If it exceeds 97 mol%, it is difficult to obtain the desired antistatic property.

As the allylamine or its Lewis acid salt, at least one of allylamine or allylamine hydrochloride, sulfate, sulfite, phosphate, phosphite, hypophosphite, nitrate, nitrite and the like is used.

The repeating structural unit of these allylamines or Lewis acid salts thereof is generally 3 to 50 mol% in the copolymer, preferably 5
It is contained as a copolymerization component in the range of ˜50 mol%. 3 mol
When it is less than%, it is difficult to obtain the desired antistatic property. 50
If it exceeds mol%, the conductivity becomes high and the antistatic property becomes good, but the solubility in an organic solvent decreases due to an increase in hydrophilicity or water absorption, so a solution coating method is adopted as a layer forming method. This is not the case. In addition, the copolymer becomes rice cake-shaped and difficult to handle.

The average degree of polymerization of the above copolymer is generally in the range of 10 to 4000. When it is less than 10, the strength of the coating layer becomes small and it tends to come off. When it exceeds 4000, the solubility in organic solvents is lowered, the viscosity is increased, and the surface state of the coating layer is deteriorated.

The vinyl chloride-allylamine-based copolymer described above contains other copolymerizable vinyl-based monomer units as a copolymerization component as long as the antistatic property is not impaired, and a terpolymer or a quaternary copolymer is included. It is also possible to use a copolymer. Examples of such other vinyl monomers include ethylene, styrene, acrylonitrile, vinyl acetate, methyl methacrylate, acrylamide and the like. Such monomer units are generally included to improve the glass transition temperature, viscosity and solubility of the copolymer.

The vinyl chloride-allylamine-based copolymer used in the present invention is synthesized, for example, as follows.

Allylamine and / or its Lewis acid salt, a solvent and a polymerization initiator are put into a high-pressure gas polymerization vessel. In this case, a Lewis acid salt of allylamine prepared in advance may be used. Alternatively, the allylamine Lewis acid salt may be prepared by charging allylamine and the Lewis acid salt into a polymerization vessel. Solvents include, for example, water, methanol, ethanol,
Acetone, benzene, toluene, hexane, dimethylformamide, dimethylsulfoxide, tetrahydrofuran, methyl ether, chloroform. As the polymerization initiator, a known radical polymerization initiator is used, and examples thereof include persulfates such as ammonium persulfate and potassium persulfate, 2,2′-diamidinyl-2,2′-azopropanedihydrochloride, azobisisobutyrate. There are azo compounds such as ronitrile and peroxides such as di-t-butyl peroxide, cumene hydroperoxide and hydrogen peroxide. The amount of the initiator is 0.01 to 10% by weight, based on the total weight of the monomers,
The preferred range is 0.1 to 1% by weight.

The pressure inside the polymerization vessel containing allylamine and / or its Lewis acid salt, a solvent and a polymerization initiator is reduced, and a vinyl chloride monomer is introduced. Then, the polymerization vessel is heated to 30 to 80 ° C, preferably 35 to 50 ° C to start the polymerization. The polymerization time is 1 to 48 hours, preferably 3 to 20 hours. After completion of the polymerization reaction, it is washed with water for several hours in order to remove unreacted allylamine monomer, allylamine salt monomer, homopolymers of these monomers and excess acid. The allylamine monomer, the allylamine salt monomer and the homopolymers of these monomers are soluble in water and therefore easily removed by washing with water.

The vinyl chloride-allylamine-based copolymer thus obtained has hydrophilicity or water absorption and is excellent in conductivity. This vinyl chloride-allylamine-based copolymer,
Elemental analysis (quantifying the weight of N atom of allylamine unit)
Fixed by. Furthermore, according to IR analysis of the copolymer, there is NH ₃ + broad absorption in 2200～3000Cm ^-1, and absorption of NH bending vibration to 1650 cm ^-1 were observed.

Therefore, in the present invention, a layer of the vinyl chloride-allylamine-based copolymer is formed on the surface of the synthetic resin molded body. As a method for forming such a layer, the above vinyl chloride-allylamine-based copolymer is dissolved in an appropriate organic solvent to prepare a solution, and this solution is applied by a coating method, a spray method or a dipping method to form a synthetic resin molded article. The method of applying to the surface is preferred.

As the organic solvent, it is preferable to use an organic solvent which does not dissolve or swell the synthetic resin molded body in a short time and has high volatility. Examples of such an organic solvent include a mixed solvent of tetrahydrofuran and cyclohexanone.

As the synthetic resin molded product, a synthetic resin molded product made of vinyl chloride resin, acrylic resin, styrene resin, polycarbonate, polyimide, polyetherimide or the like has good adhesion to the vinyl chloride-allylamine copolymer. Is preferred. Further, in the case of an olefin resin molded product such as polyethylene or polypropylene, it is preferable to use one whose surface has been subjected to corona discharge treatment to have a high wetting tension.

In the present invention, in particular, when a coating layer of the above vinyl chloride-allylamine copolymer is formed on the surface of a vinyl chloride resin molded product, the molded product and the composition layer are firmly bonded and integrated. Therefore, this combination is optimal.

As the vinyl chloride resin molded product, polyvinyl chloride resin, chlorinated polyvinyl chloride resin, vinyl chloride-ethylene copolymer resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-acrylic ester copolymer resin, chloride There is a sheet-shaped molded product or a molded product having a deformed shape, which is composed of a vinyl chloride-grafted resin obtained by graft-copolymerizing vinyl chloride with a vinyl-alkyl vinyl ether copolymer resin or an ethylene-vinyl acetate copolymer resin.

When the molded body is a sheet-shaped molded body, the solution of the composition is applied by surface coating with a roll coater, a doctor blade or the like. If the molded product is a molded product having a deformed shape, the solution of the above composition is spray-coated or the molded product is immersed in the solution.

As described above, a solution of the vinyl chloride-allylamine-based polymer is applied to the surface of the synthetic resin molded body, and then the solvent is removed by drying the solution, whereby a layer of the copolymer is formed on the surface of the molded body. Is formed. In the present invention, it is also possible to form the layer of the above-mentioned copolymer on the surface of the molded product by a melt extrusion coating method under appropriate conditions without using a solvent.

(Function) Since the vinyl chloride-allylamine-based polymer formed on the surface of the synthetic resin molded product has a repeating structural unit of allylamine or its Lewis acid salt in the molecular chain, By its origin, it has hydrophilicity or water absorbency, ions move well, and conductivity is exhibited. Therefore, it exhibits excellent antistatic properties.

Further, in the above-mentioned copolymer, allylamine or its Lewis acid salt expressing conductivity is strongly bound as a copolymerization component, and further, the adhesiveness to the synthetic resin molded article is good, and both of these actions are effective. There is no bleed or dropout,
Maintains antistatic properties.

(Example) Hereinafter, the Example and comparative example of this invention are shown.

Example 1 570 g of allylamine was dissolved in 4000 g of methanol and charged in a high-pressure polymerization vessel. The polymerization vessel was kept at 10 ° C. or lower, and 1960 g of phosphate was added dropwise. Further, as a polymerization initiator, t-butylperoxy neodecaate 24.9 was added to the polymerization vessel.
g was added. The pressure inside the polymerization vessel was reduced, and 940 g of vinyl chloride was introduced. The polymerization vessel was heated to 35 ° C. and reacted for 20 hours.
After completion of the polymerization reaction, the obtained polymer was washed with water for 2 hours to remove excess phosphoric acid, acid salt and homopolymer of allylamine phosphate. The polymer after washing with water was dehydrated by centrifugation and then dried at 40 ° C. for 24 hours. Thus, 1540 g of a vinyl chloride-allylamine phosphate copolymer was obtained.

The obtained copolymer was a white fine powder and had a degree of polymerization of 550 as determined by a viscosity method. By elemental analysis of the copolymer,
The unit of allylamine phosphate in the copolymer is 16.5 mol%
Was calculated.

This copolymer was dissolved in a mixed solvent of tetrahydrofuran / cyclohexanone / water (weight ratio 8/3/1) to give a concentration of 19
A copolymer solution of wt% was prepared.

This solution was applied to a transparent hard vinyl chloride resin plate having a thickness of 2 mm so as to have a film thickness of 10 μm by using a doctor blade to form a vinyl chloride-allylamine phosphate copolymer layer.

The surface specific resistance value, adhesiveness, and bleeding property of this layer were measured as follows. The results of these measurements are shown in Table 1.

(1) Surface resistivity After leaving the transparent hard vinyl chloride resin plate on which the above-mentioned copolymer layer was formed at 20 ° C and 65% RH for 1 month, the surface high resistance meter (H
The surface specific resistance value was measured by using irestaMCP-TESTER (manufactured by Mitsubishi Petrochemical Co., Ltd.).

(2) Adhesion Adhesiveness of 1 mm was put in the above-mentioned copolymer layer, a peeling test was carried out with cellophane tape, and the number of peeled out of 100 goggles was measured and used as a measure of adhesiveness.

(3) Bleedability The transparent hard vinyl chloride resin plate on which the above-mentioned copolymer layer is formed is allowed to stand at room temperature for 1 month, and if cloudiness or a deposit is observed on the surface, it is regarded as a failure, and if not observed at all. Was considered good.

Example 2 600 g allylamine, 2060 g phosphate and 4000 g methanol
And were charged into a high-pressure polymerization vessel. 25.0 g of t-butyl peroxy neodecanoate was added to the polymerization vessel as a polymerization initiator.
Was added. The pressure inside the polymerization vessel was reduced, and 900 g of vinyl chloride was introduced. Thereafter, by the same operation as in Example 1, 1390 g of a vinyl chloride-allylamine phosphate copolymer was obtained.

The obtained copolymer was a white powder and had a degree of polymerization of 420 according to a viscosity method. Based on the elemental analysis of the copolymer, the unit of allylamine phosphate in the copolymer was calculated to be 20.2 mol%.

Using this copolymer, the same procedure as in Example 1 was carried out. The results are shown in Table 1.

Example 3 In place of 400 g of allylamine and phosphate, 260 g of hydrochloric acid and 2900 g of methanol were charged in a high pressure polymerization reactor. In this polymerization vessel, t-butyl peroxyneodecanoate was used as a polymerization initiator.
15.0 g was added. Reduce the pressure inside the polymerization vessel to 800 g of vinyl chloride.
Was introduced. Thereafter, by the same operation as in Example 1, 570 g of a vinyl chloride-allylamine hydrochloride copolymer was obtained.

The obtained copolymer was a white powder and had a degree of polymerization of 710 as determined by a viscosity method. The unit of allylamine hydrochloride in the copolymer was calculated to be 12.3 mol% by elemental analysis of the copolymer.

Using this copolymer, the same procedure as in Example 1 was carried out. The results are shown in Table 1.

Example 4 857 g of allylamine was dissolved in 7560 g of methanol and charged in a high-pressure polymerization vessel. In this polymerization vessel, as a polymerization initiator,
45.2 g of t-butyl peroxy neodecanoate was added. The pressure inside the polymerization vessel was reduced, and 2190 g of vinyl chloride was introduced. Then, by the same operation as in Example 1, vinyl chloride-
960 g of an allylamine copolymer was obtained.

The resulting copolymer was a white powder and had a degree of polymerization of 220 according to a viscosity method. The unit of allylamine in the copolymer was calculated to be 15.0 mol% by elemental analysis of the copolymer.

Using this copolymer, the same procedure as in Example 1 was carried out. The results are shown in Table 1.

Comparative Example 1 1.8 g of t-butyl peroxyneodecanoate was dissolved in 9000 g of methanol and charged into a high-pressure polymerization vessel. The pressure inside the polymerization vessel was reduced, and 3600 g of vinyl chloride was introduced. Then, the same procedure as in Example 1 was carried out to obtain 2750 g of a vinyl chloride homopolymer.

The obtained homopolymer was a white powder and had a degree of polymerization of 940 as determined by a viscosity method. Using this polymer, the same procedure as in Example 1 was carried out. The results are shown in Table 1.

(Effects of the Invention) As described above, the method of the present invention, on the surface of the constituent resin molded body,
It forms a layer of vinyl chloride-allylamine-based copolymer, and this copolymer has hydrophilicity or water absorption and is excellent in conductivity. Therefore, the synthetic resin molding can be effectively prevented from being charged, and the cost can be reduced by reducing the layer thickness. Moreover, the above-mentioned copolymer has good adhesion to the synthetic resin molded product, and therefore the antistatic property of the molded product is maintained and maintained for a long period of time.

Claims (6)

[Claims] 1. A layer of a vinyl chloride-allylamine copolymer having a repeating structural unit of vinyl chloride and a repeating structural unit of allylamine or its Lewis acid salt is formed on the surface of a synthetic resin molding. Antistatic method for molded synthetic resin. 2. The Lewis acid salt is hydrochloride, sulfate, sulfite, phosphate, phosphite, hypophosphite, nitrate,
The antistatic method for a synthetic resin molded article according to claim 1, which is at least one of nitrites. 3. The charging of the synthetic resin molding according to claim 1, wherein the repeating unit of the allylamine or Lewis acid salt thereof is contained in the copolymer in a range of 3 to 50 mol%. Prevention method. 4. The antistatic method for a synthetic resin molding according to claim 1, wherein the repeating unit of vinyl chloride is contained in the copolymer in an amount of 50 to 97 mol%. 5. The antistatic method for a synthetic resin molded article according to claim 1, wherein the average degree of polymerization of the copolymer is in the range of 10 to 4000. 6. The antistatic method for a synthetic resin molded article according to claim 1, wherein the synthetic resin molded article is a vinyl chloride resin molded article.