JPH0218238B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing a conductive composite material, and more particularly, to an improvement in the method for manufacturing a conductive composite material in which a conductive resin layer made of vinyl chloride resin is formed on one side of a cloth base material. It is something. It is generally known that a conductive resin composition can be obtained by mixing and filling carbon black into a resin matrix. However, in order to obtain a composition that exhibits satisfactory conductivity, it is necessary to blend a large amount of carbon black into the base resin and to uniformly disperse it in the base. Conventionally, in order to uniformly disperse a large amount of carbon black into a base resin, kneading with a roll mill or kneading with an extruder has been adopted.
In systems using such a large amount of carbon black, the thickening effect becomes significant and kneading is quite difficult. Even if the above-mentioned problem of thickening effect could be solved and kneading could be achieved, there was a problem that carbon black could not be dispersed so uniformly. As a way to solve this problem,
Although the technology described in Publication No. 45297 has been proposed,
It should be noted that a kneading step is required, and this kneading step destroys the structure of the carbon black, resulting in a drawback that the conductivity does not improve in proportion to the amount of carbon black blended. Furthermore, with this proposed method, it is not possible to manufacture flexible conductive sheets or the like. Films or sheets made of synthetic resins are widely used as decorative and wear-resistant covers for a wide variety of products. These films or sheets are widely used, for example, for wall, floor and tabletop coverings, book covers, linings, clothing and automotive interior coverings. Often, films or sheets of synthetic resin are coated onto backings such as textiles, paper, felt, metal, wood, and the like. These backing materials have many purposes, the most common being to increase the strength and utility of the product and to accommodate the adhesive that secures the film or sheet. When a film or sheet made of synthetic resin and a backing material supporting the film or sheet are bonded together with an adhesive, the characteristics of the backing material are impaired and disadvantages due to the use of the adhesive appear. The present inventors completed the present invention as a result of intensive studies aimed at proposing an industrially advantageous method for manufacturing a composite material consisting of a flexible conductive synthetic resin sheet and a cloth base material. This is what I came to do. However, the gist of the present invention is that when manufacturing a conductive composite material, vinyl chloride resin is used.
Weigh out 20 to 80 parts by weight of plasticizer and 3 to 50 parts by weight of carbon black per 100 parts by weight, disperse them in water, and apply this dispersion to one side of a fabric base material to form a coating film, Next, the method for producing a conductive composite material (first invention) comprises heating and melting the coating film to melt the resin particles and adhering them to a fabric base material, followed by cooling. Further, a coating film of the above dispersion is formed on a base material having surface releasability, a cloth base material is placed on top of this coating film, and then these are heated to melt the resin particles of the coating film, and , a method for producing a conductive composite material (second invention), characterized in that the conductive composite material is cooled after being attached to a fabric base material. The present invention will be explained in detail below. In the present invention, the vinyl chloride resin refers to polyvinyl chloride and a copolymer mainly composed of vinyl chloride. Monomers that can be copolymerized with vinyl chloride include vinyl esters, vinyl ethers,
Acrylic acid or methacrylic acid and their esters, maleic acid or fumaric acid and their esters, maleic anhydride, aromatic vinyl compounds, halogenated vinylidene compounds, acrylonitrile, methacrylonitrile, ethylene,
Examples include propylene. These monomers may be partially crosslinked by adding a trace amount of a compound containing a polyfunctional group. The above-mentioned vinyl chloride resin is preferably in the form of particles produced by a conventional industrial method such as a suspension polymerization method, a microsuspension polymerization method, or an emulsion polymerization method. Although the diameter of the particles is not particularly limited, it is preferable that the average particle diameter is 50 microns or less. The average degree of polymerization is also not particularly limited, and those in the range of 500 to 2000 can be used. The base vinyl chloride resin varies depending on the thickness and feel of the resin layer of the final conductive composite material.
It is possible to combine materials having different average degrees of polymerization, materials having different average particle diameters, homopolymers, copolymers, or a combination of these. According to the present invention, a predetermined amount of the vinyl chloride resin, a plasticizer, carbon black, and other resin additives if necessary are weighed out and dispersed in water. Plasticizers that can be used in this case include phthalate esters such as dioctyl phthalate, dibenzyl phthalate, butylbenzyl phthalate, diisodecyl phthalate, didodecyl phthalate, and diundecyl phthalate; dioctyl adipate, di-n-butyl adipate. , aliphatic dibasic acid esters such as dibutyl sebacate; glycol esters such as pentaerythritol ester and diethylene glycol dibenzoate; fatty acid esters such as methyl acetyl ricinoleate; phosphorus such as tricresyl phosphate and triphenyl phosphate. Acid esters; epoxidized soybean oil,
Epoxidized oil such as epoxidized linseed oil; citric acid esters such as acetyl tributyl citrate, acetyl trioctyl citrate, tri-n-butyl citrate; trialkyl trimellitate,
Various plasticizers include tetra-n-octylpyromellitate, polypropylene adipate, and other polyester plasticizers. These plasticizers may be used alone or in combination of two or more. The amount of plasticizer can be selected within the range of 20 to 80 parts by weight based on 100 parts by weight of the vinyl chloride resin. If the amount of plasticizer is less than 20 parts by weight, a conductive composite material with excellent flexibility cannot be obtained. On the other hand, if the amount of plasticizer is more than 80 parts by weight, it becomes too soft, which is not preferable. As the carbon black that can be used in the present invention, any commonly used carbon black such as furnace type, acetylene type, channel type etc. can be used, but furnace type and acetylene type are preferable from the viewpoint of electrical conductivity. The amount of carbon black added is 3 to 50 parts by weight per 100 parts by weight of the base vinyl chloride resin. If it is less than 3 parts by weight, the conductive effect will not be exhibited, and if it exceeds 50 parts by weight, the amount added should be increased. However, the conductivity does not improve in proportion to the amount added, which is not preferable. From the viewpoint of conductivity, flexibility, etc., the range of 10 to 25 parts by weight is particularly preferable. When dispersing plasticizers and carbon black in vinyl chloride resin, add other resin additives such as resin stabilizers, ultraviolet absorbers, fillers, flame retardants, etc. to 5 parts by weight per 100 parts by weight of vinyl chloride resin. Up to 1 part can be added. PVC resin powder needs to be used in order to disperse plasticizer, carbon black, and resin additives in water.
Use a dispersant. Dispersants that can be used include those commonly known as surfactants. For example, anionic surfactants such as fatty acid soaps, alkyl sulfates, and alkyl sulfonates; cationic surfactants such as primary amine salts, secondary amine salts, and tertiary amine salts; and nonionic surfactants such as polyoxyethylene alkyl ether and polyoxyethylene alkyl amine. To disperse vinyl chloride resin powder, plasticizer, carbon black, and other resin additives in water,
A predetermined amount of each of these components is weighed out, added to water in which the dispersant is dissolved, and mixed by stirring. In addition, after dispersing only the vinyl chloride resin powder, the two components of plasticizer and other resin additives, and only carbon black in water to form three types of emulsions, the three types of emulsions were mixed together. A method of forming a dispersion may also be adopted. When preparing a dispersion containing the above components, the ratio of water to solids (vinyl chloride resin, plasticizer, carbon black, other resin additives) should be determined by adjusting the concentration of solids in the dispersion (water and solids). The range is preferably 20 to 80% by weight. This is because if the solid content concentration is lower or higher than the above range, it will be difficult to control the thickness of the resin film formed on one side of the final composite material. be. The solid content concentration is particularly preferably in the range of 40 to 60% by weight within the above range. The dispersion is stirred and mixed in order to absorb the plasticizer into the vinyl chloride resin powder and to adhere carbon black to the surface of the resin powder. On this occasion,
If the entire amount of the plasticizer dispersed in water is absorbed into the vinyl chloride resin powder, cracks will occur on the surface of the resin film of the finally obtained conductive composite material. Therefore, the amount of plasticizer absorbed into the vinyl chloride resin powder while stirring the dispersion is a portion of the blended plasticizer, preferably about half to three quarters, and the rest is not absorbed. It is preferable to have it dispersed in water. To do this, (a) add the entire amount of plasticizer to water and absorb it into the vinyl chloride resin powder by varying the stirring intensity, stirring time, etc.; (b) first add approximately half to four A method can be used, such as dispersing 3/3 of the amount in water and absorbing it into vinyl chloride resin powder, and then adding the remaining amount to water to form a dispersed state. A stirring mixer that can be used to disperse vinyl chloride resin powder, plasticizers, carbon black, and other resin additives in water is a stirring mixer that has traditionally been used to disperse solids in liquids. That's fine. When preparing the above dispersion using a stirring mixer, the dispersion may contain bubbles, gels, lumps, etc., so these should be removed using a vacuum defoamer, Hobart mixer, roll mill, filter, etc. Preferably, it is removed. According to the first aspect of the present invention, the dispersion prepared by the above method is applied to a fabric base material to form a coating film. Fabric base materials that can be used in this case include felt sheets, woven and knitted textile products. The weaving method may be any of plain weave, twill weave, satin weave, twill weave, gauze weave, and rug weave. The knitting method may be stockinette knitting, lace knitting, etc.
The raw material for the fibers may be not only plant fibers but also animal fibers, synthetic fibers, and mixtures thereof. In order to apply the dispersion liquid to the cloth base material to form a coating film, any of various coating methods known per se such as a spray coating method, a roll coating method, a gravure coating method, a reverse coating method, a knife coating method, etc. can be used. It depends. The thickness of the coating film formed on one side of the fabric base material is such that it can be attached to the fabric base material by volatilizing water and melting the resin particles in the next heating and melting process, and The adjustment should be made so as not to sacrifice the flexibility of the conductive composite material. In order to satisfy these various requirements, the thickness of the resin film formed on the cloth base material is preferably adjusted to be in the range of 0.05 to 2 mm. When the coating film is heated, water evaporates, so the thickness of the resin film of the final conductive composite material is thinner than the original coating film by a proportion corresponding to the water contained in it. Become. If the resin film is too thin, it will not have sufficient strength and will be easily torn, making it less practical. According to the first aspect of the present invention, the cloth base material on which a coating film is formed on one side by the above method is sent to a heating furnace alone or while supported by a thin metal plate, a thin heat-resistant resin plate, etc., and is heated and coated. The water in the film is evaporated, and then the surface or the entire particle of the resin particle is melted,
At the same time, it is attached to a fabric base material. If the moisture in the coating film evaporates, the resin particles stick to the surface, the particles stick to the surface, or the entire particle melts rapidly, many small cracks will occur in the resin film of the final conductive composite material. There are many. In order to prevent the formation of such small cracks, before heating the resin particle surface or the entire particle to melt it,
It is preferable to perform preliminary drying by heating within a temperature range of 40 to 100°C for 5 minutes or less to volatilize a considerable proportion of the water in the coating film. The coating film is heated to almost completely volatilize the moisture, with or without the above pre-drying, and to melt the resin particle surface or the entire particle to form a resin film, and to apply this resin film to a fabric base. Attach it to the material.
If the heating temperature at this time is too low, the resin particles will not melt even if heated for a long time, making it impossible to obtain a resin film with excellent strength, which is not preferable. The heating temperature is
Glass transition point, average particle size, of vinyl chloride resin
Various selections can be made depending on the degree of polymerization, the number of parts of plasticizer added, the number of parts of carbon black added, the thickness of the conductive composite material to be finally obtained, etc. The heating temperature range for melting the resin particles is preferably in the range of 160 to 260°C. According to the first aspect of the present invention, heating and melting operations are performed as described above to melt the surface or the entire particle of the resin particle to form a resin film, and at the same time, this resin film is also attached to the cloth substrate. Combine, cool, and wind up into a roll. According to the second aspect of the present invention, the dispersion prepared by the above method is first applied to a substrate having surface releasability. This substrate functions to support the coating film based on the dispersion. The surface releasable base material is preferably composed of a thin metal plate, paper, a heat-resistant resin plate, or the like. It is preferable to impart surface releasability to the surface of these base materials on which the coating film is to be formed, by applying a release agent or the like so that the finally obtained conductive composite material can be easily peeled off. In order to form a coating film by applying the dispersion liquid to a base material having surface releasability, the dispersion liquid can be coated by a method known per se, such as a spray coating method, a roll coating method, a gravure coating method, a reverse coating method, a knife coating method, etc. Any of the following coating methods may be used. The thickness of the coating film formed on one side of the base material with surface releasability is the thickness of the resin film of the conductive composite material obtained after the next heating, welding, and adhesion process (the thickness of the resin film formed on the fabric base layered in the next process) Even when the resin has penetrated into the pores of the material, the thickness of the resin film formed on the surface of the fabric base material is preferably adjusted to be within the range of 0.05 to 2 mm. When the coating film is heated in the next heating step, water evaporates, so the film becomes thinner at a rate corresponding to the water contained therein, as in the previous case. According to the second aspect of the present invention, a cloth base material is layered on the coating film formed by the above method. The cloth base material that can be used in this case is the same as that used in the first invention exemplified above. According to the second aspect of the present invention, a stacked body formed by the above method (a base material having surface releasability,
(consisting of a coating film and a fabric base material) is heated to volatilize the moisture in the coating film, and then the surface or the entire particle of the resin particles is melted to form a resin film, and at the same time, this resin film is attached to a fabric base material. Attach it to the material. In order to volatilize the water in the coating film, it is preferable to perform preliminary drying as in the case of the first invention. The heating temperature range for melting the resin particles after preliminary drying is preferably in the range of 170 to 270°C. According to the second aspect of the present invention, the heating and melting operations as described above are performed to melt the surface or the entire particle of the resin particle to form a resin film, and at the same time, this resin film is also attached to the cloth substrate. The mixture is combined, cooled, peeled from the releasable substrate, and wound into a roll. The conductive composite material obtained by the method of the present invention is
It can be processed by cutting, gluing, sewing, etc. in the same way as cloth with a regular synthetic resin sheet attached. The conductive composite material obtained by the method of the present invention can be used for bag-like containers for storing items that are sensitive to static electricity, partition curtains for clean rooms that are sensitive to dust scattering, work clothes for use in clean rooms, workbenches in clean rooms, and work rooms. It can be used to manufacture mats, workroom upholstery, and other various items installed in environments where static electricity is averse. The present invention has particularly remarkable effects as described below, and its industrial utility value is extremely large. (1) When the method of the present invention is used, a composite material having excellent conductivity and flexibility can be easily produced. (2) The composite material produced by the method of the present invention is easy to manufacture because the resin film with excellent conductivity and flexibility is integrally attached to the cloth base material without using an adhesive. It is preferable because it is not affected by adhesives like conventional products. (3) According to the present invention, the resin film integrated into the cloth base material is formed without going through the kneading process as in the conventional method, so the structure of the carbon black is not destroyed and the resin film is integrated into the cloth base material. The inherent conductivity of black can be effectively exhibited. Hereinafter, the present invention will be explained in detail based on examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. Example 1 From the ratio of 50% by weight of polyvinyl chloride powder (=1000, average particle size 40 microns) produced by suspension polymerization method, 47% by weight of water, and 3% by weight of sodium todecylbenzenesulfonate (DBS) A mixed solution A was prepared by stirring and mixing the following components. On the other hand, a mixture B was prepared by stirring and mixing three components consisting of 65% by weight of dioctyl phthalate, 32% by weight of water, and 3% by weight of ammonium oleate. Furthermore, carbon black (Lion Akzo Co., Ltd.)
Mixed liquid C was prepared by stirring and mixing three components consisting of 30% by weight (manufactured by Ketsuin Black FC), 67% by weight of water, and 3% by weight of DBS. Mixed liquid A, mixed liquid B, and mixed liquid C were mixed at a ratio of 1:0.39:0.17, respectively, to prepare dispersion liquid 1. The above-mentioned dispersion was applied to one side of a nylon woven fabric (a woven fabric made of gauze weave with threads having a diameter of 70 microns and a hole size of 200 microns) by a knife coating method to form a coating film. The nylon woven fabric with this coating film was placed on a thin metal plate and placed in a hot air oven adjusted to 80℃ for 3 days.
The coating film was pre-dried for a few minutes. Next, this coated nylon woven fabric was placed on a thin metal plate and placed in a hot air oven adjusted to 180°C.
After standing for a minute to evaporate most of the water, the polyvinyl chloride particles are melted into a film, and at the same time,
This membrane was also integrally attached to the surface of the nylon fabric. After the above heating and melting operations were completed, it was cooled to obtain a conductive composite material in which a conductive resin film with a thickness of about 0.15 mm was formed on one side of the fabric base material. The volume resistivity of the obtained conductive composite material was measured in accordance with JIS K6923, and the tensile strength was measured in accordance with JIS K6732. The results are shown in Table 1. Example 2 Mixed liquid A and mixed liquid B prepared in Example 1
and Mixture C were mixed at a ratio of 1:0.39:0.25, respectively, to prepare a dispersion. This dispersion was applied to one side of a nylon woven fabric of the same type as used in Example 1, and the same procedures as in Example 1 were followed to perform preliminary drying, heating, melting, and cooling operations. In this way, a conductive composite material was obtained in which a conductive resin film with a thickness of about 0.15 mm was formed on one side of a cloth base material. The volume resistivity of the obtained conductive composite material was measured. The results are shown in Table 1. Example 3 Mixed liquid A and mixed liquid B prepared in Example 1
and Mixture C were mixed at a ratio of 1:0.39:0.34, respectively, to prepare a dispersion. This dispersion was applied to one side of a nylon woven fabric of the same type as used in Example 1, and the same procedures as in Example 1 were followed to perform preliminary drying, heating, melting, and cooling operations. In this way, a conductive composite material was obtained in which a conductive resin film with a thickness of about 0.15 mm was formed on one side of a cloth base material. The volume resistivity of the obtained conductive composite material was measured. The results are shown in Table 1. Example 4 The dispersion prepared in Example 1 was applied to the surface of commercially available release paper (paper whose surface is coated with a release agent) by a knife coating method to form a coating film. . Next, a nylon fabric similar to that used in Example 1 was stacked and pressed on top of this coating film to form a stacked body. This stacked body was placed on a thin metal plate and kept in a hot air oven adjusted to 80° C. for 3 minutes to pre-dry the coating film. Next, this stacked body was placed on a metal plate and placed in a hot air oven adjusted to 180℃.
After standing for a minute to volatilize the water almost completely, the polyvinyl chloride particles are melted into a film.
At the same time, this membrane was also integrally attached to the surface of the nylon fabric. After the above heating and melting operations were completed, it was cooled and peeled off from the release paper to obtain a conductive composite material with a conductive resin film of about 0.15 mm thick on one side. The volume resistivity and tensile strength of the obtained conductive composite material were measured. The results are shown in Table 1. Example 5 The dispersion prepared in Example 2 was applied to the surface of the same type of release paper as used in Example 4 to form a coating film. Next, a nylon woven fabric of the same type as that used in Example 1 was stacked and pressed on top of this coating film to form a stacked body. This stacked body was subjected to preliminary drying, heating, melting, and cooling operations in the same manner as in Example 4. In this way, the thickness can be
A conductive composite material on which a 0.15 mm conductive resin film was formed was obtained. The volume resistivity of the obtained conductive composite material was measured. The results are shown in Table 1. Example 6 The dispersion prepared in Example 3 was applied to the surface of the same type of release paper as used in Example 4 to form a coating film. Next, a nylon woven fabric of the same type as that used in Example 1 was stacked and pressed on top of this coating film to form a stacked body. This stacked body was subjected to preliminary drying, heating, melting, and cooling operations in the same manner as in Example 4.
In this way, on one side of the fabric substrate, approximately 0.15 mm thick
A conductive composite material on which a conductive resin film of mm was formed was obtained. The volume resistivity of the obtained conductive composite material was measured. The results are shown in Table 1. Comparative Example 1 The dispersion prepared in Example 1 was applied to the surface of the same type of release paper as used in the same example to form a coating film. This coating film is not overlaid with nylon woven fabric,
It was sent to a hot air oven and subjected to preliminary drying, heating, melting, and cooling operations. In this way, the thickness is about 0.15mm
A conductive sheet was obtained. The volume resistivity and tensile strength of the obtained conductive sheet were measured. The results are shown in Table 1. Comparative Example 2 The dispersion prepared in Example 3 was applied to the surface of the same type of release paper as used in the same example to form a coating film. This coating film is not overlaid with nylon woven fabric,
It was sent to a hot air oven and subjected to preliminary drying, heating, melting, and cooling operations. In this way, a conductive sheet with a thickness of about 0.15 mm was obtained. The volume resistivity and tensile strength of the obtained conductive sheet were measured. The results are shown in Table 1.

[Table] From Table 1, the following becomes clear. (1) The composite material obtained by the method of the present invention has excellent conductivity and strength. (2) On the other hand, a conductive resin sheet to which a cloth base material is not attached has excellent conductivity but low strength.

Claims (1)

[Claims] 1. In producing the conductive composite material, 20 to 80 parts by weight of plasticizer per 100 parts by weight of vinyl chloride resin,
Weigh and disperse 3 to 50 parts by weight of each carbon black in water, apply this dispersion to one side of a fabric base material to form a coating film, and then heat and melt this coating film to form resin particles. A method for producing a conductive composite material, which comprises melting it, adhering it to a fabric base material, and then cooling it. 2. In producing the conductive composite material, 20 to 80 parts by weight of plasticizer per 100 parts by weight of vinyl chloride resin,
Weigh 3 to 50 parts by weight of each carbon black and disperse them in water, apply this dispersion to a base material with surface releasability to form a coating film, and layer a fabric base material on top of this coating film, A method for producing a conductive composite material, which comprises heating the resin particles to melt the resin particles of the coating film and adhering them to a fabric base material, followed by cooling.