Vinyl chloride sheet and process for producing the same

Abstract

To provide a vinyl chloride sheet having low odor and excellent conductivity, and to provide a method for producing the same.SOLUTION: The polyvinyl chloride sheet includes a lower layer containing polyvinyl chloride and conductive carbon, a conductive layer bonded on the lower layer and containing polyvinyl chloride and conductive carbon, a surface layer bonded on the conductive layer and containing polyvinyl chloride and conductive carbon fibers, and metal powders inserted between the lower layer and the conductive layer and between the conductive layer and the surface layer, wherein the metal powders are attached to a bonding surface of the lower layer to the conductive layer and a bonding surface of the conductive layer to the surface layer, respectively, in an amount of 0. 5g / m2 or more and 1. 0g / m2 or less.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vinyl chloride sheet and a method for producing the same. [Background technology]

[0002] Polyvinyl chloride sheets containing antistatic plasticizers are known as conductive sheets used on floors, shelves, workbenches, etc. in clean rooms where electronic devices are manufactured. However, depending on the environment in which such polyvinyl chloride sheets are used, the liquid antistatic plasticizer volatilizes, causing an odor.

[0003] Therefore, by changing the antistatic plasticizer to a powdered conductive material, it is possible to reduce the odor.Patent Document 1 discloses a conductive flooring material that is formed by pressing together a flooring sheet covering made from a conductive composition in which a conductive metal compound is added to vinyl chloride resin and a backing sheet made from a conductive composition in which carbon black is added to vinyl chloride resin. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 61-142248 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when an attempt is made to obtain conductivity by using a powdered conductive material in a vinyl chloride resin composition as in Patent Document 1, charge transfer between layers tends to be poor, resulting in high electrical resistance between layers.On the other hand, when a metal powder is used in a vinyl chloride resin composition, the conductivity is improved too much, posing a problem of the possibility of electric shock to the human body.

[0006] The present invention has been made in view of the problems inherent in the prior art, and an object of the present invention is to provide a vinyl chloride sheet that is low in odor and has excellent electrical conductivity, and a method for producing the same. [Means for solving the problem]

[0007] A vinyl chloride sheet according to an embodiment of the present invention comprises a lower layer containing vinyl chloride resin and conductive carbon, a conductive layer laminated on the lower layer and containing vinyl chloride resin and conductive carbon, a surface layer laminated on the conductive layer and containing vinyl chloride resin and conductive carbon fiber, and metal powder inserted between the lower layer and the conductive layer and between the conductive layer and the surface layer. The vinyl chloride sheet further comprises a metal powder of 0.5 g / m on the surface of the lower layer to be bonded to the conductive layer and on the surface of the conductive layer to be bonded to the surface layer. 2 More than 1.0g / m 2 The following is attached.

[0008] Another aspect of the present invention is a method for producing a vinyl chloride sheet, which includes a lower layer containing vinyl chloride resin and conductive carbon, a conductive layer laminated on the lower layer and containing vinyl chloride resin and conductive carbon, a surface layer laminated on the conductive layer and containing vinyl chloride resin and conductive carbon fiber, and metal powder inserted between the lower layer and the conductive layer and between the conductive layer and the surface layer. The method also includes applying 0.5 g / m of metal powder to the surface of the lower layer that is to be laminated with the conductive layer. 2 More than 1.0g / m 2 After the above steps, a conductive layer is attached to the lower layer, and a metal powder is applied to the surface of the conductive layer to be bonded to the surface of the conductive layer at a rate of 0.5 g / m. 2 More than 1.0g / m 2 and subsequently laminating a surface layer onto the conductive layer. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a vinyl chloride sheet that is low in odor and has excellent electrical conductivity, and a method for producing the same. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view showing the bonding surfaces of the conductive layer and the lower layer of the vinyl chloride sheet according to the present embodiment. FIG. [Figure 2] 1 is a cross-sectional view showing a vinyl chloride sheet according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] The vinyl chloride sheet and the method for manufacturing the same according to the present embodiment will be described in detail below. Note that the dimensional proportions in the drawings are exaggerated for the convenience of explanation and may differ from the actual proportions.

[0012] The vinyl chloride sheet 1 according to this embodiment includes a lower layer 30 containing vinyl chloride resin and conductive carbon. The vinyl chloride sheet 1 also includes a conductive layer 20 that is laminated onto the lower layer 30 and contains vinyl chloride resin and conductive carbon. The vinyl chloride sheet 1 also includes a surface layer 10 that is laminated onto the conductive layer 20 and contains vinyl chloride resin and conductive carbon fiber. The vinyl chloride sheet 1 also includes metal powder that is inserted between the lower layer 30 and the conductive layer 20, and between the conductive layer 20 and the surface layer 10. Each component of this embodiment will be described in detail below.

[0013] [Surface layer 10] The surface layer 10 is a layer located on the surface of the vinyl chloride sheet 1. Here, the layer located on the surface of the vinyl chloride sheet 1 means the layer located on the top when the vinyl chloride sheet 1 is installed. The surface layer 10 contains vinyl chloride resin and conductive carbon fibers, and is a layer having electrical conductivity.

[0014] The vinyl chloride resin used in the surface layer 10 may be a homopolymer obtained by polymerizing a vinyl chloride monomer alone, or a copolymer obtained by polymerizing a vinyl chloride monomer with a monomer other than vinyl chloride. Examples of copolymers of a vinyl chloride monomer with a monomer other than vinyl chloride include vinyl chloride-vinyl acetate copolymer, vinyl chloride-ethylene copolymer, vinyl chloride-propylene copolymer, vinyl chloride-styrene copolymer, vinyl chloride-isobutylene copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-styrene-maleic anhydride copolymer, vinyl chloride-styrene-acrylonitrile copolymer, vinyl chloride-butadiene copolymer, vinyl chloride-isoprene copolymer, vinyl chloride-chlorinated propylene copolymer, vinyl chloride-vinylidene chloride-vinyl acetate copolymer, vinyl chloride-maleic ester copolymer, vinyl chloride-methacrylic ester copolymer, vinyl chloride-acrylonitrile copolymer, and vinyl chloride-various vinyl ether copolymers. These vinyl chloride resins may be used alone or in combination. Modified versions of these vinyl chloride resins may also be used. The modified vinyl chloride resin may be chlorinated polyvinyl chloride, etc. The polymerization method for the vinyl chloride resin is not particularly limited and may be bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, or the like.

[0015] The average degree of polymerization (weight-average degree of polymerization) of the vinyl chloride resin is not particularly limited, but is preferably 500 to 5000, more preferably 1000 to 3000, and even more preferably 1300 to 2000. Having an average degree of polymerization of 500 or more can suppress a decrease in the abrasion resistance of the resulting vinyl chloride sheet. Furthermore, having an average degree of polymerization of 5000 or less can suppress an increase in melt viscosity during extrusion molding of the vinyl chloride sheet, thereby preventing deterioration of kneading and molding processability. In the vinyl chloride sheet of this embodiment, one or more vinyl chloride resins within the above polymerization degree ranges may be used in combination. The average degree of polymerization can be determined according to Japanese Industrial Standard JIS K 6720-2:1999 (Plastics - Vinyl chloride homopolymer and copolymer (PVC) - Part 2: Preparation of test specimens and determination of properties).

[0016] The surface layer 10 contains conductive carbon fiber to impart conductivity to the vinyl chloride sheet. By using conductive carbon fiber in the surface layer 10 and not using an antistatic plasticizer, odor can be reduced and conductivity can be improved. The conductive carbon fiber used in the surface layer 10 is a carbon fiber that is conductive in itself. The conductive carbon fiber may be metal-plated.

[0017] The surface layer 10 preferably contains 10 to 20 parts by mass of conductive carbon fiber per 100 parts by mass of vinyl chloride resin. Having a conductive carbon fiber content of 10 parts by mass or more can provide sufficient conductivity. Having a conductive carbon fiber content of 20 parts by mass or less can reduce adverse effects on the mechanical properties of the vinyl chloride sheet.

[0018] The surface layer 10 may contain a plasticizer to adjust the hardness of the vinyl chloride sheet. Known plasticizers can be used. The plasticizer is preferably at least one selected from the group consisting of aliphatic dibasic acid plasticizers, epoxy plasticizers, phthalic acid plasticizers, adipic acid plasticizers, trimellitic acid plasticizers, pyromellitic acid ester plasticizers, phosphate ester plasticizers, and ether ester plasticizers, and more preferably contains at least one of a phthalic acid plasticizer and an adipic acid plasticizer.

[0019] The phthalate plasticizer may be at least one phthalate ester selected from the group consisting of di-2-ethylhexyl phthalate (DEHP), di-n-octyl phthalate (DNOP), diisononyl phthalate (DINP), dinonyl phthalate (DNP), diisodecyl phthalate (DIDP), and ditridecyl phthalate.

[0020] The adipic acid plasticizer may be, for example, at least one adipic acid ester selected from the group consisting of bis(2-ethylhexyl) adipate (DOA), diisononyl adipate (DINA), and diisodecyl adipate (DIDA).

[0021] The trimellitic acid-based plasticizer may be, for example, at least one trimellitic acid ester selected from the group consisting of trioctyl trimellitate (TOTM) and triisodecyl trimellitate.

[0022] The surface layer 10 preferably contains 40 to 50 parts by mass of plasticizer per 100 parts by mass of vinyl chloride resin. A plasticizer content of 40 parts by mass or more can prevent the vinyl chloride sheet from becoming too hard. Furthermore, a plasticizer content of 50 parts by mass or less can prevent adverse effects on the releasability of the vinyl chloride sheet.

[0023] The surface layer 10 may contain a stabilizer to improve thermal stability. The stabilizer inhibits the generation of hydrogen chloride when the vinyl chloride resin is heated and stabilizes the properties of the vinyl chloride resin. A lead-free stabilizer is preferably used. Examples of the lead-free stabilizer include at least one stabilizer selected from the group consisting of Ca-Mg-Zn stabilizers, Ca-Zn stabilizers, Zn-Mg stabilizers, Sn stabilizers, Ba stabilizers, Zn stabilizers, and Ca-based stabilizers. Of these, Ca-Mg-Zn stabilizers, Ca-Zn stabilizers, and Zn-Mg stabilizers are more preferred due to their excellent heat resistance and thermal stability. Furthermore, from the viewpoint of the releasability of the vinyl chloride sheet, the lead-free stabilizer preferably contains a metal stearate, such as zinc stearate or calcium stearate.

[0024] The surface layer 10 preferably contains 10 to 20 parts by mass of stabilizer per 100 parts by mass of vinyl chloride resin. Having a stabilizer content of 10 parts by mass or more improves thermal stability. Having a stabilizer content of 20 parts by mass or less reduces adverse effects on the mechanical properties of the vinyl chloride sheet.

[0025] In addition to the conductive carbon fiber, plasticizer, and stabilizer described above, various additives may be blended in appropriate amounts to the extent that they do not impair the effects of this embodiment to the vinyl chloride resin that constitutes the surface layer 10. Examples of additives include fillers, flame retardants, crosslinking agents, crosslinking aids, antioxidants, processing aids, metal deactivators, reinforcing agents, UV absorbers, lubricants, pigments, dyes, colorants, antistatic agents, and foaming agents.

[0026] To increase the strength of the vinyl chloride sheet, the surface layer 10 may contain a filler. Examples of fillers include inorganic fillers such as calcium carbonate, talc, kaolin clay, synthetic silicic acid, quartz powder, calcium sulfate, calcium sulfite, calcium hydroxide, magnesium carbonate, aluminum hydroxide, titanium oxide, asbestos, silica, glass fiber, and mineral fiber; and organic fillers such as wood flour, coconut shell flour, pulp flour, crosslinked polyester particles, polystyrene particles, carbon fiber, and natural fibers. Calcium carbonate is preferred as a filler because of its good compatibility with vinyl chloride resin and excellent thermal and dimensional stability.

[0027] The surface layer 10 may contain a flame retardant. The flame retardant may be, for example, at least one of an organic flame retardant and an inorganic flame retardant. Examples of organic flame retardants include halogen-based flame retardants such as bromine-based flame retardants and chlorine-based flame retardants, and phosphorus-based flame retardants such as phosphate esters, condensed phosphate esters, cyclic phosphorus compounds, and red phosphorus. Examples of inorganic flame retardants include at least one metal hydroxide selected from the group consisting of aluminum hydroxide, magnesium hydroxide, and calcium hydroxide. These flame retardants may be used alone or in combination. The flame retardant may include, for example, an organic flame retardant and an inorganic flame retardant.

[0028] The organic flame retardant preferably contains at least a halogen-based flame retardant. The halogen-based flame retardant can capture hydroxyl radicals that promote the combustion of the vinyl chloride sheet and suppress the combustion of the vinyl chloride sheet. The halogen-based flame retardant may be, for example, a compound in which at least one halogen is substituted on an organic compound. Examples of the halogen-based flame retardant include fluorine-based flame retardants, chlorine-based flame retardants, bromine-based flame retardants, and iodine-based flame retardants. The halogen-based flame retardant is preferably a bromine-based flame retardant.

[0029] Brominated flame retardants include, for example, 1,2-bis(bromophenyl)ethane, 1,2-bis(pentabromophenyl)ethane, hexabromobenzene, ethylene bis-dibromonorbornanedicarboximide, ethylene bis-tetrabromophthalimide, tetrabromobisphenol S, tris(2,3-dibromopropyl-1)isocyanurate, hexabromocyclododecane (HBCD), octabromophenyl ether, tetrabromobisphenol A (TBA), TBA epoxy oligomer or polymer, TBA-bis(2,3-dibromopropyl ether), decabromodiphenyl oxide, polydibromophenylene oxide, bis(tribromophenoxy)ethane, ethylene bis-pentabromobenzene, dibromophenyl ether, tetrabromobisphenol A (TBA), octabromophenyl ether, tetra ... Examples of suitable flame retardants include 1,2-bis(pentabromophenyl)ethane and tetrabromobisphenol A. Examples of suitable flame retardants include 1,2-bis(pentabromophenyl)ethane and tetrabromobisphenol A. Examples of suitable flame retardants include 1,2-bis(pentabromophenyl)ethane and tetrabromobisphenol A.

[0030] The inorganic flame retardant preferably contains at least a metal hydroxide. Metal hydroxides are widely used as flame retardants and are relatively less expensive than bromine-based flame retardants. Examples of metal hydroxides that can be used include one or more metal compounds having hydroxyl groups or crystal water, such as magnesium hydroxide (Mg(OH)), aluminum hydroxide (Al(OH)), calcium hydroxide (Ca(OH)), basic magnesium carbonate (mMgCO·Mg(OH)·nH2O), hydrated aluminum silicate (aluminum silicate hydrate, Al2O3·3SiO2·nH2O), and hydrated magnesium silicate (magnesium silicate pentahydrate, Mg2SiO8·5H2O). Among these, magnesium hydroxide is particularly preferred as the metal hydroxide.

[0031] The surface layer 10 may contain an antioxidant. Examples of antioxidants include phenol-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants. To provide the vinyl chloride sheet with sufficient heat resistance, an antioxidant such as hindered phenol that captures radicals may be combined with an antioxidant such as thioether that decomposes peroxides.

[0032] The vinyl chloride resin composition constituting the surface layer 10 is prepared by melt-kneading the vinyl chloride resin, plasticizer, stabilizer, and other additives, and any known method can be used for this purpose. For example, the vinyl chloride resin composition can be obtained by pre-blending the components in advance using a high-speed mixer such as a Henschel mixer, and then kneading them using a known kneader such as a Banbury mixer, kneader, or roll mill.

[0033] The method for forming the surface layer 10 is not particularly limited, but it can be formed, for example, by a method in which a molten vinyl chloride resin composition is extruded through a T-die and stretched to form a sheet. The sheet-like extrudate may be cooled with a cooling roll or the like when taken up, if necessary. It may also be formed by applying a known forming method such as calendar molding or press molding.

[0034] The thickness of the surface layer 10 is preferably 0.2 mm or more and 0.4 mm or less, and more preferably 0.25 mm or more and 0.35 mm or less. By making the thickness of the surface layer 10 as described above, the conductivity of the vinyl chloride sheet 1 can be maintained.

[0035] [Conductive layer 20] The conductive layer 20 is a layer located between the surface layer 10 and the lower layer 30, and is a layer that mainly controls the conductivity of the vinyl chloride sheet 1. The conductive layer 20 contains vinyl chloride resin and conductive carbon.

[0036] The vinyl chloride resin used for the conductive layer 20 may be the same as the vinyl chloride resin used for the surface layer 10 .

[0037] The conductive layer 20 contains conductive carbon to impart conductivity to the vinyl chloride sheet. The use of conductive carbon in the conductive layer 20 without the use of an antistatic plasticizer reduces odor and improves conductivity. The conductive carbon used in the conductive layer 20 is preferably at least one selected from the group consisting of graphite, graphene, carbon fiber, single-walled carbon nanotubes (SWCNT), double-walled carbon nanotubes (DWCNT), multi-walled carbon nanotubes (MWCNT), carbon nanohorns, carbon nanofibers, carbon black, and fullerenes. The above-mentioned carbon fiber may also be the conductive carbon fiber used in the surface layer 10.

[0038] The conductive layer 20 preferably contains 35 to 55 parts by mass of conductive carbon per 100 parts by mass of vinyl chloride resin. A conductive carbon content of 35 parts by mass or more can provide sufficient conductivity. Furthermore, a conductive carbon content of 55 parts by mass or less can prevent adverse effects on the mechanical properties of the vinyl chloride sheet.

[0039] The conductive layer 20 may contain a plasticizer to adjust the hardness of the vinyl chloride sheet. The plasticizer used in the conductive layer 20 may be the same material as the plasticizer used in the surface layer 10.

[0040] The conductive layer 20 preferably contains 50 to 70 parts by mass of plasticizer per 100 parts by mass of vinyl chloride resin. By containing 50 parts by mass or more of plasticizer, it is possible to prevent the vinyl chloride sheet from becoming too hard. Furthermore, by containing 70 parts by mass or less of plasticizer, it is possible to prevent adverse effects on the releasability of the vinyl chloride sheet.

[0041] The conductive layer 20 may contain a stabilizer to improve thermal stability. The stabilizer used in the conductive layer 20 may be the same material as the stabilizer used in the surface layer 10.

[0042] The conductive layer 20 preferably contains 5 to 10 parts by mass of stabilizer per 100 parts by mass of vinyl chloride resin. By containing 5 parts by mass or more of stabilizer, thermal stability can be improved. Furthermore, by containing 10 parts by mass or less of stabilizer, adverse effects on conductivity can be reduced.

[0043] In addition to the above-mentioned conductive carbon, plasticizer, and stabilizer, various additives can be blended in appropriate amounts to the extent that they do not impair the effects of this embodiment as additives to be added to the vinyl chloride resin that constitutes the conductive layer 20. The additives used in the conductive layer 20 can be the same materials as the additives used in the surface layer 10.

[0044] The vinyl chloride resin composition constituting the conductive layer 20 can be prepared by the same method as that for the surface layer 10 and the conductive layer 20 can be formed by the same method.

[0045] The thickness of the conductive layer 20 is preferably 0.1 mm or more and 0.3 mm or less, and more preferably 0.15 mm or more and 0.25 mm or less. By making the thickness of the surface layer 10 as described above, conductivity can be maintained.

[0046] [Lower 30] The lower layer 30 is the layer located at the bottom of the vinyl chloride sheet 1. Here, the layer located at the bottom of the vinyl chloride sheet 1 means the layer located at the bottom when the vinyl chloride sheet 1 is installed. The lower layer 30 contains vinyl chloride resin and conductive carbon and is a conductive layer, and further, it is a layer that prevents the vinyl chloride sheet 1 from warping toward the surface layer 10 side.

[0047] The vinyl chloride resin used in the lower layer 30 may be the same as the vinyl chloride resin used in the surface layer 10 and the conductive layer 20 .

[0048] The lower layer 30 contains conductive carbon to impart conductivity to the vinyl chloride sheet. By using conductive carbon in the lower layer 30 and not using an antistatic plasticizer, odor can be reduced and conductivity can be improved. The conductive carbon used in the lower layer 30 can be the same material as the conductive carbon used in the conductive layer 20.

[0049] The lower layer 30 preferably contains 10 to 20 parts by mass of conductive carbon per 100 parts by mass of vinyl chloride resin. Having a conductive carbon content of 10 parts by mass or more can provide sufficient conductivity. Having a conductive carbon content of 20 parts by mass or less can reduce adverse effects on the mechanical properties of the vinyl chloride sheet.

[0050] The lower layer 30 may contain a plasticizer to adjust the hardness of the vinyl chloride sheet. The plasticizer used in the lower layer 30 may be the same as the plasticizer used in the surface layer 10 and the conductive layer 20.

[0051] The lower layer 30 preferably contains 50 to 60 parts by mass of plasticizer per 100 parts by mass of vinyl chloride resin. A plasticizer content of 50 parts by mass or more can prevent the vinyl chloride sheet from becoming too hard. Furthermore, a plasticizer content of 60 parts by mass or less can prevent adverse effects on the releasability of the vinyl chloride sheet.

[0052] The lower layer 30 may contain a stabilizer to improve thermal stability. The stabilizer used in the lower layer 30 may be the same material as the stabilizers used in the surface layer 10 and the conductive layer 20.

[0053] The lower layer 30 preferably contains 10 to 20 parts by mass of stabilizer per 100 parts by mass of vinyl chloride resin. A stabilizer content of 10 parts by mass or more can improve thermal stability. Furthermore, a stabilizer content of 20 parts by mass or less can prevent adverse effects on electrical conductivity.

[0054] In addition to the above-mentioned conductive carbon, plasticizer, and stabilizer, various other additives may be blended in appropriate amounts to the extent that they do not impair the effects of this embodiment as additives to be added to the vinyl chloride resin constituting the lower layer 30. The additives used in the lower layer 30 may be the same materials as those used in the surface layer 10 and the conductive layer 20.

[0055] The vinyl chloride resin composition constituting the lower layer 30 can be prepared by the same method as that for the surface layer 10 and the conductive layer 20 and the method for molding the lower layer 30 can be used.

[0056] The thickness of the lower layer 30 is preferably 1.4 mm or more and 1.6 mm or less. 、 The thickness of the lower layer 30 is preferably 1.45 mm or more and 1.55 mm or less. By setting the thickness of the lower layer 30 as described above, the electrical conductivity and mechanical properties of the vinyl chloride sheet can be maintained. The lower layer 30 may also be composed of multiple layers.

[0057] [Vinyl chloride sheet 1] As shown in Figure 2, vinyl chloride sheet 1 can be produced by laminating layers in the following order from the bottom: lower layer 30, conductive layer 20, and surface layer 10. By laminating conductive layer 20 so that it is in direct contact with surface layer 10, when vinyl chloride sheet 1 is used as a conductive sheet, static electricity is less likely to accumulate, and the ease of electrical current flow from the human body can be improved.

[0058] When the layers are bonded together, metal powder is inserted between the lower layer 30 and the conductive layer 20, and between the conductive layer 20 and the surface layer 10. Specifically, as shown in FIG. 1 , metal powder is applied to the bonding surface 31 of the lower layer 30 to be bonded to the conductive layer 20, and to the bonding surface 21 of the conductive layer 20 to be bonded to the surface 10, before the layers are bonded together. Then, metal powder is applied to the bonding surfaces 31 and 21 at a rate of 0.5 g / m 2 More than 1.0g / m 2 The lower layer 30, the conductive layer 20, and the surface layer 10 are bonded together in the following state: 2 By adhering the metal powder to a thickness of 1.0 g / m or more, the metal powder helps charge transfer between the layers, providing sufficient conductivity. 2 By adhering the film in this manner, it is possible to prevent adverse effects on the bonding of the layers.

[0059] The metal powder is not particularly limited as long as it is a conductive metal powder, and examples thereof include copper powder, stainless steel powder, silver powder, aluminum powder, iron powder, and zinc powder. From the viewpoints of conductivity and availability, copper powder and stainless steel powder are preferred. The average particle diameter D of the metal powder 50 From the viewpoint of electrical conductivity, D is preferably 1 to 500 μm, more preferably 3 to 300 μm. 50 The metal powder may be a mixture of multiple types of metal powder.

[0060] The method for adhering the metal powder to the bonding surfaces 31 and 21 is not particularly limited as long as it is a method that can uniformly or almost uniformly adhere the metal powder to the bonding surfaces 31 and 21. For example, the metal powder may be sprinkled onto the bonding surfaces 31 and 21 through a mesh.

[0061] The method for laminating the layers when producing the vinyl chloride sheet 1, i.e., the lamination method, is not particularly limited, but examples include a method in which the layers are stacked and then heated and pressed together. The thickness of the vinyl chloride sheet 1 is preferably 1.8 mm or more and 2.2 mm or less, and more preferably 1.9 mm or more and 2.1 mm or less. By adjusting the thickness of the vinyl chloride sheet 1 to the above range, conductivity can be maintained.

[0062] The conductivity of vinyl chloride sheet 1 is 2.5 × 10 4 Ω or more 1.0×10 7 Ω or less is preferable, and 2.5×10 4 Ω or more 7.5×10 6 It is more preferable that the volume resistivity is Ω or less. When the volume resistivity of the vinyl chloride sheet 1 is in this range, sufficient conductivity can be obtained and the possibility of electric shock to the human body can be reduced. The volume resistivity can be measured in accordance with NFPA99.

[0063] The conductivity of the vinyl chloride sheet 1 is such that the surface resistance between two points is 1.0 × 10 7 Ω or less is preferable, and 7.0×10 6 It is more preferable that the surface resistance between two points of the vinyl chloride sheet 1 is in this range. When the surface resistance between two points of the vinyl chloride sheet 1 is in this range, the vinyl chloride sheet 1 can have sufficient conductivity. The surface resistance between two points can be measured in accordance with NFPA99.

[0064] The vinyl chloride sheet 1 has good dent resistance. "Dent resistance" refers to the ease of impact absorption, and can be evaluated, for example, by a dent test in accordance with JIS A 1454 (Test Method for Polymer-Based Flooring Materials). The dent depth in the dent test is preferably 0.3 mm or more, and more preferably 0.32 mm or more, at 23°C. When the dent depth of the vinyl chloride sheet 1 is within this range, sufficient dent resistance can be achieved.

[0065] As described above, the vinyl chloride sheet 1 includes a lower layer 30 containing vinyl chloride resin and conductive carbon. The vinyl chloride sheet 1 also includes a conductive layer 20 that is laminated on top of the lower layer 30 and contains vinyl chloride resin and conductive carbon. The vinyl chloride sheet 1 also includes a surface layer 10 that is laminated on top of the conductive layer 20 and contains vinyl chloride resin and conductive carbon fibers. The vinyl chloride sheet 1 also includes metal powder that is inserted between the lower layer 30 and the conductive layer 20, and between the conductive layer 20 and the surface layer 10. The surface 31 of the lower layer 30 that is laminated with the conductive layer 20, and the surface 21 of the conductive layer 20 that is laminated with the surface layer 10 each contain metal powder at a density of 0.5 g / m. 2 More than 1.0g / m 2 The following are attached. Such vinyl chloride sheet 1 reduces odor by not using antistatic plasticizers, and the conductivity of each layer can be improved by using conductive carbon fiber or conductive carbon. Furthermore, inserting metal powder when bonding each layer helps charge transfer between the layers, providing a vinyl chloride sheet with excellent conductivity. Therefore, vinyl chloride sheet 1 can provide a vinyl chloride sheet with low odor and excellent conductivity.

[0066] [Manufacturing method of vinyl chloride sheet 1] The manufacturing method of the vinyl chloride sheet 1 in this embodiment is a manufacturing method of the vinyl chloride sheet 1 comprising a lower layer 30, a conductive layer 20, a surface layer 10, and metal powder inserted between the lower layer 30 and the conductive layer 20, and between the conductive layer 20 and the surface layer 10, respectively.

[0067] In the method for producing the vinyl chloride sheet 1, the surface layer 10, the conductive layer 20, and the lower layer 30 can be produced by the methods described above.

[0068] As described above, the vinyl chloride sheet 1 can be produced by laminating the lower layer 30, the conductive layer 20, and the surface layer 10 in this order from the bottom. The vinyl chloride sheet 1 is produced by applying 0.5 g / m of metal powder to the surface 31 of the lower layer 30 that is to be bonded to the conductive layer 20. 2 More than 1.0g / m2 After the above-described deposition, the method includes a step of laminating the conductive layer 20 onto the lower layer 30. This step allows the metal powder to be inserted between the lower layer 30 and the conductive layer 20.

[0069] In addition, the method for manufacturing the vinyl chloride sheet 1 is to apply 0.5 g / m of metal powder to the bonding surface 21 of the conductive layer 20 with the surface layer 10. 2 More than 1.0g / m 2 After the above-described adhesion, the method includes a step of laminating the surface layer 10 onto the conductive layer 20. This step allows the metal powder to be inserted between the conductive layer 20 and the surface layer 10.

[0070] Such vinyl chloride sheet 1 reduces odor by not using antistatic plasticizers, and the conductivity of each layer can be improved by using conductive carbon fiber or conductive carbon. Furthermore, by inserting metal powder when bonding the layers together, charge transfer between the layers can be promoted, providing a vinyl chloride sheet with excellent conductivity. Therefore, the method for producing vinyl chloride sheet 1 can provide a vinyl chloride sheet with low odor and excellent conductivity. [Example]

[0071] Hereinafter, the present embodiment will be described in more detail with reference to examples and comparative examples, but the present embodiment is not limited to these examples.

[0072] (Preparation of test samples) Vinyl chloride sheets (surface layer, conductive layer, and lower layer) were prepared with the compositions (unit: parts by mass) shown in Tables 1 to 5. Specifically, to prepare the sheets for each layer, vinyl chloride resin and other additives were first blended and melt-kneaded using a twin-screw kneading extruder at a temperature of 200°C. The extruded strands were water-cooled and passed through a pelletizer to obtain pellets. The obtained vinyl chloride resin pellets were molded using a T-die film molding machine at a temperature of 200°C to obtain sheets for each layer. The thickness of the surface layer was 0.3±0.05 mm, the thickness of the conductive layer was 0.2±0.05 mm, and the thickness of the lower layer was 1.5±0.05 mm.

[0073] Based on the metal powder adhesion amounts shown in Tables 1 to 5, metal powder was sprinkled through a mesh onto the bonding surface of the lower layer with the conductive layer and the bonding surface of the conductive layer with the surface layer. The layers were then stacked and heated at 200°C and pressed together to a thickness of 2.0±0.1 mm. In this manner, test samples for evaluation as vinyl chloride sheets were prepared.

[0074] (Vinyl chloride resin) Shin-Etsu Chemical Co., Ltd. Product name: TK-1100 (average degree of polymerization: 1100)

[0075] (plasticizer) DINP (Diisononyl phthalate) manufactured by J-Plus Corporation

[0076] (stabilizer) Sakai Chemical Industry Co., Ltd. OW-5200 (Ca-Zn stabilizer, metal stearate)

[0077] (Conductive carbon fiber) Mitsubishi Chemical Corporation TR03M

[0078] (Conductive carbon) Asahi Carbon Co., Ltd. Asahi F-200GS

[0079] (metal powder) SUS304L (stainless steel powder) manufactured by Sakuma Special Steel Co., Ltd.

[0080] [evaluation] <Volume resistivity> The volume resistivity of the vinyl chloride sheet was measured in accordance with NFPA99.

[0081] <Surface resistance between two points> The surface resistance between two points of the vinyl chloride sheet was measured in accordance with NFPA99.

[0082] <Dent amount> The amount of denting of the vinyl chloride sheet was evaluated by a denting test in accordance with JIS A 1454.

[0083] <Odor> The odor of the vinyl chloride sheet was evaluated by an odor test. Specifically, 600 g of the vinyl chloride sheet test sample was placed in a 1 L beaker and heated at 50°C for 48 hours. The odor was then evaluated by sensory evaluation using a 5-point scale. The evaluation criteria were as follows: a barely detectable odor was rated "1" (pass); a weak odor that was easy to identify was rated "2" (pass); an easily detectable odor was rated "3" (fail); a slightly unpleasant odor was rated "4" (fail); and a very unpleasant odor was rated "5" (fail).

[0084] [Evaluation results] The results of evaluation by the above-mentioned evaluation methods are shown in Tables 1 to 5.

[0085] [Table 1]

[0086] [Table 2]

[0087] [Table 3]

[0088] [Table 4]

[0089] [Table 5]

[0090] As shown in Tables 1 and 2, the test samples of Examples 1 to 24 had a volume resistivity of 2.5 × 10 4 Ω or more 1.0×10 7Ω or less, and the surface resistance between two points is 1.0 x 10 7 The resistance to odor was Ω or less, the dent depth was 0.3 mm or more, and the odor evaluation was acceptable in all cases. Therefore, it was confirmed that the vinyl chloride sheets produced in Examples 1 to 24 were vinyl chloride sheets with low odor and excellent conductivity.

[0091] As shown in Tables 3 and 4, the test samples of Comparative Examples 1, 2, 13, and 14 had a surface resistance of 1.0 × 10 because the content of conductive carbon fiber in the surface layer was less than 10 parts by mass relative to 100 parts by mass of vinyl chloride resin. 7 In addition, in the test samples of Comparative Examples 3, 4, 15, and 16, the content of conductive carbon in the conductive layer was less than 35 parts by mass relative to 100 parts by mass of vinyl chloride resin, and therefore the volume resistivity was 1.0 × 10 7 Furthermore, in the test samples of Comparative Examples 5, 6, 17, and 18, the content of conductive carbon in the lower layer was less than 10 parts by mass relative to 100 parts by mass of vinyl chloride resin, and therefore the volume resistivity was 1.0 × 10 7 It is larger than Ω.

[0092] As shown in Tables 3 and 4, the test samples of Comparative Examples 7, 8, 19, and 20 had a surface layer containing more than 20 parts by mass of conductive carbon fiber per 100 parts by mass of vinyl chloride resin, resulting in a dent depth of less than 0.3 mm. The test samples of Comparative Examples 9, 10, 21, and 22 had a conductive layer containing more than 55 parts by mass of conductive carbon per 100 parts by mass of vinyl chloride resin, resulting in a dent depth of less than 0.3 mm. The test samples of Comparative Examples 11, 12, 23, and 24 had a lower layer containing more than 20 parts by mass of conductive carbon per 100 parts by mass of vinyl chloride resin, resulting in a dent depth of less than 0.3 mm.

[0093] On the other hand, as shown in Table 5, the test samples of Comparative Examples 25 to 36 had a metal powder adhesion amount of 0.5 g / m 2 Because the volume resistivity was less than 1.0 × 10, the charge transfer between the layers was poor.7 It is larger than Ω.

[0094] These results show that by producing a vinyl chloride sheet using specific ingredients and a specific composition, a vinyl chloride sheet with low odor and excellent conductivity can be obtained.

[0095] Although the present embodiment has been described above, the present embodiment is not limited to this, and various modifications are possible within the scope of the gist of the present embodiment. [Explanation of symbols]

[0096] 1 vinyl chloride sheet 10 Surface layer 20 Conductive layer 21 Bonding surface 30 Lower layer 31 Bonding surface

Claims

1. a lower layer containing vinyl chloride resin and conductive carbon; a conductive layer that is laminated on the lower layer and contains vinyl chloride resin and conductive carbon; a surface layer that is laminated on the conductive layer and contains vinyl chloride resin and conductive carbon fibers; a metal powder inserted between the lower layer and the conductive layer, and between the conductive layer and the surface layer; Equipped with The metal powder is applied to the surface of the lower layer to be bonded to the conductive layer and the surface of the conductive layer to be bonded to the surface layer at a rate of 0.5 g / m. ２ 1.0g / m or more ２ The vinyl chloride sheet attached below.

2. 2. The vinyl chloride sheet according to claim 1, wherein the surface layer contains, relative to 100 parts by mass of vinyl chloride resin, a conductive carbon fiber content of 10 parts by mass or more and 20 parts by mass or less, a plasticizer content of 40 parts by mass or more and 50 parts by mass or less, and a stabilizer content of 10 parts by mass or more and 20 parts by mass or less.

3. The conductive layer is a vinyl chloride sheet according to claim 1 or 2, wherein the conductive carbon content is 35 to 55 parts by mass, the plasticizer content is 50 to 70 parts by mass, and the stabilizer content is 5 to 10 parts by mass, per 100 parts by mass of vinyl chloride resin.

4. 3. The vinyl chloride sheet according to claim 1 or 2, wherein the lower layer contains, relative to 100 parts by mass of vinyl chloride resin, a conductive carbon content of 10 parts by mass or more and 20 parts by mass or less, a plasticizer content of 50 parts by mass or more and 60 parts by mass or less, and a stabilizer content of 10 parts by mass or more and 20 parts by mass or less.

5. a lower layer containing vinyl chloride resin and conductive carbon; a conductive layer that is laminated on the lower layer and contains vinyl chloride resin and conductive carbon; a surface layer that is laminated on the conductive layer and contains vinyl chloride resin and conductive carbon fibers; a metal powder inserted between the lower layer and the conductive layer, and between the conductive layer and the surface layer; A method for producing a vinyl chloride sheet, comprising: The metal powder is applied in an amount of 0.5 g / m to the bonding surface of the lower layer with the conductive layer. ２ 1.0g / m or more ２ and thereafter laminating the conductive layer onto the underlayer. The metal powder was applied to the surface of the conductive layer that was to be bonded to the surface layer at 0.5 g / m ２ 1.0g / m or more ２ and thereafter, laminating the surface layer onto the conductive layer. A method for producing a vinyl chloride sheet, comprising:

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