JPH0233064B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a conductive resin composition that can be freely colored and that can be used to obtain molded articles having sufficient antistatic performance. [Prior Art] A measure to prevent static electricity from forming on rubber or plastic molded products is to lower the electrical resistance of the molded product and quickly ground and dissipate static electricity generated by friction. The following methods are known as methods for lowering 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 of adding surfactants called antistatic agents or similar substances to rubber or plastic. [Problems to be Solved by the Invention] Although the method (1) above is very effective in preventing electrostatic charging, it cannot be colored freely and is limited to metallic colors. Moreover, it is very expensive and lacks economic efficiency. Furthermore, it is desirable that the electrical resistance of molded products be within a certain range to prevent the risk of electric shock due to low voltage electricity, but it is difficult to stably manufacture such products using metal powder or metal fibers. is extremely difficult. The method (2) above has the drawback that, although carbon black is often used as an inexpensive conductivity imparting agent, 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) above has the advantage of being able to be colored freely, it incorporates a surfactant that has poor compatibility with rubber and plastic and easily absorbs moisture, and bleeds it onto the surface to lower the surface resistance. It dissipates static electricity from the surface, and relies on surface resistance, which is easily influenced 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, semiconductor parts such as IC, LSI, and electronic equipment factories are being used to prevent production failures due to the attraction of micron and submicron dust particles due to the generation of static electricity, and in office automation rooms, etc. The use of conductive floors is being considered to prevent computer malfunctions and circuit damage. In this case, the above (3) allows you to freely color for aesthetic reasons.
It is preferable to use a sheet obtained by the method of
It is difficult to use alone due to concerns about its ability to prevent static electricity. As a countermeasure to this problem, it is possible to use sheets laminated with the sheet obtained by method (3) above on the front side and the highly conductive sheet obtained by method (1) or (2) above on the back side. It will be done. However, in such a laminated sheet, the static electricity charged on the front side leaks to the conductive layer on the back side and is grounded, but in this case, the volume resistance is more important than the surface resistance, and the sheet using the method (3) above Since the volume resistivity cannot be lowered in this case, a sufficient antistatic effect cannot be obtained. The present invention has been made based on the above,
The object of the present invention is to provide a conductive resin composition which can be colored in any color and which can produce molded products having excellent antistatic effects. [Means for Solving the Problems] The conductive resin composition of the present invention comprises 100 parts by weight of a polymer component containing 95 to 20 parts by weight of a polyvinyl chloride resin and 5 to 80 parts by weight of an acrylonitrile-butadiene copolymer. is characterized by containing 5 to 100 parts by weight of a glycol fatty acid ester or glycol having a volume resistivity of 10 ⁸ Ω-cm or less, one of which is a fatty acid and the other of which is an ester of an aromatic carboxylic acid. be. In the present invention, the polyvinyl chloride resin may be any resin that normally contains 50% by weight or more of vinyl chloride, such as a homopolymer of vinyl chloride, or a copolymer of vinyl chloride and a monomer copolymerizable therewith. It may be a polymer or a graft copolymer with other resins. There are no particular restrictions on the acrylonitrile-butadiene copolymer, but from the viewpoint of compatibility with polyvinyl chloride resin and electrical resistance, it is desirable to have a high acrylonitrile content. It is best to choose accordingly. The content ratio of polyvinyl chloride resin and acrylonitrile-butadiene copolymer in the polymer component is 95 to 20/5 to 80 in weight ratio of polyvinyl chloride resin/acrylonitrile-butadiene copolymer.
It needs to be within the range of If the amount of acrylonitrile-butadiene copolymer is less than 5 parts by weight, it will not be possible to obtain the desired conductivity, and if it is more than 80 parts by weight, raw rubber-like properties will become noticeable and processability will be poor, making it impossible to obtain a product with a smooth surface. . Additionally, vulcanization is required, increasing the number of manufacturing steps. Examples of the plasticizer used in the present invention include glycol fatty acid esters having a volume resistivity of 10 ⁸ Ω-cm or less, or esters in which one of the glycols is a fatty acid and the other is an aromatic carboxylic acid. By using such a plasticizer, it is possible to obtain a product that has an excellent antistatic effect and is free from bleeding. Examples of glycol fatty acid esters having a volume resistivity of 10 ⁸ Ω-cm or less include diethylene glycol-dicaproate ester and triethylene glycol-dicaproate ester.
Examples include dicaprylic acid ester, triethylene glycol-dicapric acid ester, and the like. Examples of esters of glycols having a volume resistivity of 10 ⁸ Ω-cm or less in which one side is a fatty acid and the other side is an aromatic carboxylic acid include esters of phthalic acid and triethylene glycol-monocaprylic acid ester. In addition, in the present invention, the above-mentioned plasticizer
An electrolyte of about 0.005 to 2% may be added. The electrolyte is preferably a chemically stable electrolyte that does not easily deteriorate, such as lithium chloride or sodium chloride. A plasticizer of a glycol fatty acid ester or an ester of glycol in which one side is a fatty acid and the other side is an aromatic carboxylic acid and has a volume resistivity of 10 ⁸ Ω-cm or less for a polymer component containing a polyvinyl chloride resin and an acrylonitrile-butadiene copolymer. The amount of plasticizer added is 5 to 100 parts by weight per 100 parts by weight of the polymer component.
It must be within the range of parts by weight. If it is less than 5 parts by weight, the desired volume resistivity cannot be obtained;
The volume resistivity is almost saturated at about parts by weight,
Even if the amount is increased more than this, the electrical resistance will hardly change, and instead it will lead to deterioration of compatibility and deterioration of mechanical properties, making it unsuitable for use in the field of thermoplastic resins. In the present invention, in addition to the above ingredients, of course, plasticizers such as DOP, other compounding agents, such as stabilizers, antioxidants, crosslinking agents, vulcanizing agents, vulcanization aids, lubricants, and processing aids are used. , a flame retardant, a filler, a coloring agent, a ray absorber, etc. can be used as appropriate, and the composition can be made without any practical problems. The conductive resin 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. [Example] According to the compounding ratios shown in the Examples in Table 1 and the Comparative Examples in Table 2, a compound was kneaded using an electric heating two rolls and molded with a high-pressure steam press.
A sheet with a thickness of 1 mm was produced. The results of evaluating the volume resistivity, hardness, and presence or absence of bleeding for this sheet are shown in the lower columns of Tables 1 and 2. The volume resistivity is based on the Japan Rubber Association standard.
Based on SRIS2304 and its commentary, the hardness is UF
Measurements were made using a Shore Dual Prometer Type A, and bleed was evaluated by observing the surface with the naked eye after allowing it to stand at room temperature for 10 days.

【table】

[Table] As is clear from Table 1, Examples 1 to 4 within the scope of the present invention have perfect electrical resistance to prevent electrostatic charging, and maintain stable characteristics for a long period of time because there is no bleeding. can. Table 2 describes Comparative Examples 1 to 5 which are outside the scope of the present invention. Comparative Examples 1 to 4 are cases in which a plasticizer having a volume resistivity outside the range of the present invention is used, and an electrical resistance that can be expected to have a good antistatic effect cannot be obtained. In addition, when a large amount of plasticizer is blended as in Comparative Example 4, bleeding occurs.
Comparative Example 5 is a case where polyvinyl chloride alone is used, and a good antistatic effect cannot be expected. [Effects of the Invention] As explained above, according to the present invention, a conductive product having excellent antistatic performance can be obtained without using a conductivity imparting agent such as carbon black or metal. Therefore, the product can be colored freely and its aesthetic appearance can be improved. Further, according to the present invention, a conductive product without bleeding can be obtained, and stable antistatic performance can be maintained for a long period of time.

Claims (1)

[Claims] 1 100 parts by weight of a polymer component containing 95 to 20 parts by weight of polyvinyl chloride resin and 5 to 80 parts by weight of acrylonitrile-butadiene copolymer has a volume resistivity.
1. A conductive resin composition comprising 5 to 100 parts by weight of a glycol fatty acid ester having a resistance of 10 ⁸ Ω-cm or less or a plasticizer in which one of the glycols is a fatty acid and the other is an ester of an aromatic carboxylic acid.