JPS62185729A - Electroconductive resin composition and electroconductive floor sheet - Google Patents

Abstract

PURPOSE:To obtain the titled composition which an give a molding which can be colored in any desired color and is excellent in antistatic property, by adding a phosphoric ester and LiCl to a polymer component comprising a PVC resin and an acrylonitrile/butadiene copolymer. CONSTITUTION:The titled composition is obtained by adding 5-100pts.wt. normally liquid volatile phosphoric ester (e.g., tricresyl phosphate), LiCl powder of a particle size <=80 mesh and, optionally, a plasticizer such as DOP and other additives to 100pts.wt. polymer component comprising 95-20wt% PVC resin having an average degree of polymerization >=2,000 and a vinyl chloride content >=50wt% and 5-80wt% acrylonitrile/butadiene copolymer. This composition is molded into a sheet and this sheet is used as an antistatic sheet on a floor or a desk or as a first sheet which is laminated with a second sheet comprising a resin composition formed by mixing, e.g., a rubber or a plastic with, e.g., carbon black and having a still larger electric conductivity to obtain the titled electroconductive floor sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention provides a conductive resin composition that can freely obtain a molded article having η color performance and sufficient antistatic performance.
and a conductive floor sheet using this resin composition.

[Prior art] As a measure to prevent static electricity from forming in rubber or plastic molded products, it is necessary to lower the electrical resistance of the molded product.
The purpose is to quickly ground and dissipate static electricity generated by friction.

The following methods are known so far to lower the electrical resistance of rubber or plastic.

(1) A method of adding highly conductive metal powder or fibers such as silver, copper, stainless steel, or nickel to rubber or plastic.

(2) A method of adding carbon black or carbon fiber to rubber or plastic.

(3) A method in which a surfactant called an antistatic agent or something similar is added to rubber or plastic.

[Problem to be Solved by the Invention The method (1) is very effective in preventing electrostatic charging, but it cannot be colored in any desired color and is limited to metallic colors.

Moreover, it is very expensive and lacks economic efficiency.

Generally speaking, it is desirable that the electrical resistance of molded products be within a certain range to prevent the risk of electric shock from low-voltage electricity, but metal powder and metal! It is extremely difficult to stably manufacture such products using IF fibers.

In method (2), carbon black is often used as an inexpensive conductivity imparting agent, but it has the drawback that the hue is limited to black.

Further, even with this method, it is difficult to industrially and stably produce molded products that are free from the risk of electric shock due to low voltage electricity.

Although method (3) has the advantage of being able to be colored freely, it incorporates a surfactant that has poor compatibility with rubber and plastics and easily absorbs moisture, and bleeds onto the surface to lower surface resistance and reduce static electricity. It is obtained by releasing electricity from the surface, and relies on surface resistance, which is an electrical resistance that is easily affected by environmental conditions, and lacks stability in antistatic performance. In particular, the antistatic effect will be considerably reduced in a low humidity environment. Moreover, the duration of antistatic performance is short.

On the other hand, in recent years, in semiconductor parts such as RC and LSI and electronic equipment factories, etc., to prevent production failures due to the adsorption of micron and submicron dust particles due to the generation of static electricity, and in office automation rooms, etc., due to static electricity. The use of conductive floors is being considered to prevent computer malfunctions and circuit damage.

In this case, from the viewpoint of aesthetics, it is preferable to use a sheet obtained by the method (3), which can be colored freely, but it is difficult to use it alone due to concerns about its antistatic performance. As a countermeasure for this, turn the sheet obtained by method (3) on the front side,
It is conceivable to use a sheet in which the fjI layer is placed on the back side of a sheet with high conductivity obtained by method (+) or (2).

In such a laminated sheet, static electricity charged on the front side leaks to the conductive layer on the back side and is grounded, but in this case, volume resistance is more important than surface resistance, and surfactants and similar charged The sheet produced by method (3), in which something called an inhibitor was added, could not lower the volume resistance;
A sufficient antistatic effect will not be obtained.

The present invention has been made based on the above, and provides a conductive resin composition that can be colored in any color and realizes a molded product having excellent antistatic performance, and a conductive floor sheet that has excellent antistatic performance. The purpose is to provide the following.

[Means for Solving the Problems] The conductive resin composition of the present invention is formed by containing a phosphate ester and lithium chloride in a polymer component containing a polyvinyl chloride resin and an acrylonitrile-butadiene copolymer. It is characterized by:

Further, the conductive floor sheet of the present invention includes a first sheet made of a resin composition in which a polymer component containing a polyvinyl chloride resin and an acrylonitrile-butadiene copolymer contains a phosphoric acid ester and lithium chloride; A second sheet having higher conductivity than the first sheet is laminated with a resin composition made of rubber or plastic containing at least one of carbon black, carbon azure, metal powder, or metal fiber. It is characterized by the fact that

In the present invention, the polyvinyl chloride resin may be any resin that normally contains 50% by weight or more of vinyl chloride.
The average degree of polymerization of the polyvinyl chloride resin, which may be a polymer of vinyl chloride, a copolymer of vinyl chloride and a monomer copolymerizable with it, or a graft copolymer with other resin materials, is particularly Although not limited to, for good mechanical strength 2.
000 or more is preferable.

There are no particular restrictions on the acrylonitrile-butadiene copolymer, but one with a high acrylonitrile content is desirable from the viewpoint of compatibility with the phosphoric acid ester.
The molecular weight and the presence or absence of partial crosslinking are preferably selected depending on the intended use.

The content ratio of the polyvinyl chloride resin and the acrylonitrile-butadiene copolymer is 96 to 2 in weight ratio of the polyvinyl chloride resin/acrylonitrile-butadiene copolymer.
A range of 075 to 80 is desirable. If the acrylonitrile-butadiene copolymer is less than 5% by weight, the compatibility with the phosphate ester will be poor, and it will be necessary to keep the amount of the phosphate ester low from the viewpoint of bleeding, and the desired conductivity will not be achieved. There is a tendency to become less able to do so. Acrylonitrile-
When the butadiene copolymer content exceeds 80% by weight, raw rubber-like properties become noticeable, processability tends to be poor and it is difficult to obtain a product with a smooth surface, and vulcanization becomes necessary, increasing the number of manufacturing steps.

In the present invention, the phosphoric acid ester is not particularly limited, but one that is liquid at room temperature and has low volatility is desirable.

For example, tricresyl phosphate, cresyl diphenyl phosphate, di(2,3-dibromopropyl) 2
．． 3-dichloropropyl ester, di(2-ethylhexyl) phosphate, dioctyl phosphate, triamyl phosphate, tributoxyethyl phosphate, tri(2-chloroethyl) phosphate, tri(chloropropyl phosphate) ) ester, tricresyl phosphate, tri(2,3-dibromopropyl) phosphate, tri(dichloropropyl) phosphate, etc. may be used.

The amount of phosphoric acid ester added to the polymer component containing polyvinyl chloride resin and acrylonitrile-butadiene copolymer is not particularly limited as long as the desired volume resistance can be obtained, but it is 5 parts per 100 M parts of the polymer component. ~100
Parts by weight ranges are preferred. If it is less than 6 parts by weight, it will be difficult to obtain the desired volume resistivity, and if it is about 100 parts by weight, the volume resistivity will be almost saturated, and if it is increased more than this, the electrical resistance will hardly change, and the compatibility will worsen. , it may lead to a decrease in mechanical properties and may become unsuitable for applications in the field of thermoplastic resins.

Lithium chloride is preferably a powder with a size of 80 mesh or less. Lithium chloride is slightly deliquescent and tends to clump, so it may be mixed with powder such as alumina powder or quartz powder. It is also possible to add such a mixture as it is as a compounding agent.

In the present invention, in addition to the above components, D
Degradable agents such as OP, other compounding agents such as stabilizers, antioxidants, crosslinking agents, vulcanizing agents, vulcanization aids, lubricants, processing aids,
Flame retardants, fillers, colorants, ultraviolet absorbers, etc. can be used as appropriate, and the composition can be made without any practical problems.

The conductive composition thus obtained can be formed into a sheet and used as an antistatic sheet for floors or desks. Further, it can be used as curtain fabric or wallpaper, and furthermore, it can be dissolved or dispersed in a solvent and used as an antistatic paint.

The sheet made of the conductive composition of the present invention is laminated with a conventionally known conductive sheet, that is, a sheet made of rubber or plastic containing carbon black, carbon fiber, metal powder, metal fiber, etc. to impart conductivity. By doing so, the antistatic performance can be further improved, and it is also useful for improving the aesthetic appearance.

[Example] A compound kneaded using two electrically heated rolls was molded using a high-pressure steam press according to the compounding ratio shown in Example 6 in Table 1 to produce a sheet with a thickness of 1 mm.

This sheet was evaluated for volume resistivity, surface resistivity, and the presence or absence of bleeding, and the results are shown in the lower column of Table 1.

The volume resistivity and surface resistivity were each measured based on the Japan Rubber Association Standard 5RIS2304 and its commentary, and bleeding was evaluated by observing the surface with the naked eye after leaving it at room temperature for 10 days.

As shown in Table 1, in Examples 1 to 4 within the scope of the present invention, the electrical resistance was significantly lowered due to the addition of lithium chloride, which was satisfactory in preventing electrostatic charging.

Comparative Examples 1 to 4 all show examples in which lithium chloride is not used, and the electrical resistance is large and a good antistatic effect cannot be expected.

Comparative Example 5 uses polyvinyl chloride alone, but it cannot be used because of severe bleeding.

Example 5 As shown in FIG.
f! A sheet was prepared.

Color conductive J'3'l was prepared by kneading a composition containing 1 part by weight of phthalocyanine green, a green coloring agent, in addition to the composition of Example 1 using two electrically heated rolls, and using a steam press to form a 0.5 mm It was manufactured by molding to a thickness of .

Conductive N2 was prepared in the same manner as in the case of color conductive layer 1, using a composition containing 100 parts by weight of polyvinyl chloride resin, 70 parts by weight of dioctyl phthalate, 80 parts by weight of Carbon Blauk, and 5 parts by weight of other stabilizers. It was produced by molding it to a thickness of 2.5 mm.

The volume resistivity of this conductive layer 2 was 3×10 2 Ω-cm.

Next, the colored conductive layer 1 and the conductive layer 2 were laminated using a steam press to produce a laminated sheet with a colored surface as shown in FIG. 1.

Comparative Example 6 Color conductive layer 1 was prepared by adding 100 parts by weight of polyvinyl chloride resin, 50 parts by weight of dioctyl phthalate, and a nonionic antistatic agent (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Resist) 141) 2
A laminate sheet was produced in the same manner as in Example 5, except that the composition was prepared by adding 6 parts by weight of other stabilizers and the like.

The results of measuring the electrical resistance of the laminated sheets produced in Example 5 and Comparative Example 6 are shown in Table 2.

The electrical resistance was measured as shown in FIG. That is, a voltage was applied to the copper plate 4 connected to the conductive layer 2 by a DC power supply 5, the current flowing through the 60 mmφ electrode 3 was measured with an ammeter 7, and the ′:lt air resistance was calculated from Ohm's law. . 6 is a voltmeter.

The laminated sheet of Comparative Example 6 in Table 2 had high electrical resistance, and the lamination effect was not exhibited.

[Effects of the Invention] As explained above, according to the present invention, a molded article that can be colored in any color and has excellent antistatic performance can be realized.

Further, by laminating the sheet obtained from the composition of the present invention with a black conductive sheet containing carbon black or the like and having excellent conductivity, a colored sheet having even better antistatic performance can be realized.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of one embodiment of the laminated sheet according to the present invention, and FIG. 2 is an explanatory diagram of a method for measuring the electrical resistance of the laminated sheet. 1: Conductive colored sheet, 2: Conductive sheet.

Claims (2)

[Claims] (1) Polyvinyl chloride resin and acrylonitrile
A conductive resin composition comprising a polymer component containing a butadiene copolymer containing a phosphoric acid ester and lithium chloride. (2) Polyvinyl chloride resin and acrylonitrile
A first sheet made of a resin composition containing a phosphoric acid ester and lithium chloride in a polymer component containing a butadiene copolymer, and at least one of carbon black, carbon fiber, metal powder, or metal fiber in rubber or plastic. 1. A conductive floor sheet comprising: a second sheet having a higher conductivity than the first sheet made of a resin composition containing one of the above-mentioned resin compositions;