Antistatic sheet and manufacturing method thereof

Abstract

To provide an antistatic sheet and a manufacturing method thereof.SOLUTION: An antistatic sheet includes: a conductive color pattern layer; a transparent protective layer positioned on the conductive color pattern layer to protect a surface of the conductive color pattern layer; a body layer positioned under the conductive color pattern layer; and a lower layer positioned under the body layer and having a lower surface formed with an embossing structure in contact with a floor. A manufacturing method of an antistatic sheet forms an antistatic sheet by including an antistatic agent and forming a lower layer with an embossing structure, thereby preventing a floor from being contaminated by carbon contained in the conventional lower layer, and stably preventing static electricity that may occur on the floor of industrial sites such as semiconductor manufacturing plants or various offices, thereby manufacturing the antistatic sheet capable of preventing harmful effects such as damage to devices or parts caused by static electricity.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an antistatic sheet and a method for manufacturing the same, and more particularly to an antistatic sheet that contains an antistatic agent and has an embossed lower layer, thereby preventing floor contamination caused by carbon contained in the conventional lower layer and stably preventing static electricity that may occur on floors in industrial sites such as semiconductor manufacturing plants and various offices, thereby preventing adverse effects such as damage to devices and parts caused by static electricity, and a method for manufacturing the same. [Background technology]

[0002] Generally, in semiconductor assembly lines, antistatic sheets are used to prevent damage to products caused by static electricity. For example, when a worker works at a workbench, the worker places an antistatic sheet on top of the workbench, places the semiconductor components that are the work targets on the sheet, and then performs tasks such as assembly.

[0003] Among conventional antistatic sheets, those widely used in semiconductor product assembly lines and the like include a method in which a fiber fabric made by weaving and arranging carbon threads is applied to the top plate of the antistatic sheet, or a method in which nanometal powder is dissolved and electrochemically coated onto the surface of the fiber fabric for the top plate, or the method in which it is immersed in a tissue.

[0004] However, the conventional methods have some limitations.

[0005] For example, in the case of a fiber fabric in which carbon threads are woven and arranged, the woven and arranged carbon threads are distinguished from the original color of the fiber fabric, resulting in a striped surface pattern. When used on a workbench, there is a problem that the optical illusion caused by the surface pattern of the carbon threads can cause eye fatigue for the worker.

[0006] Furthermore, in the case of fiber fabrics in which carbon threads are woven and arranged, the surface resistance of the tabletop may vary depending on the direction and spacing in which the carbon threads are woven and arranged, so a stable antistatic effect may not be obtained depending on the size of the semiconductor components and the position and direction in which the worker places the semiconductor components that are the object of their work.

[0007] Furthermore, conventional antistatic sheets must have electrostatic properties, so they use PVC mixed with an antistatic agent or carbon and a conductive metal, but such conventional structures are difficult to manufacture, and when carbon is used, the carbon is black, so it is not possible to form various color patterns, resulting in an undesirable appearance.

[0008] Existing antistatic sheets have a separate conductive sheet layer containing carbon or metal in the middle, and a pattern layer (or color layer) is placed on top of this conductive sheet layer to improve its appearance. However, the pattern layer is not conductive because it uses general pigments, and through holes must be made to allow electricity to pass through it, which causes manufacturing problems and significantly reduces durability.

[0009] Furthermore, conventional antistatic sheets include a lower layer below the main layer, which is made of a mixture of soft PVC and carbon material. However, the carbon material contained in the lower layer reduces the adhesive strength between the antistatic sheet and the floor surface, causing the antistatic sheet to separate from the floor surface over time. In addition, the carbon dust contained in the lower layer can stain the area around the floor, which is unsightly, and the use of carbon increases manufacturing costs. Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention aims to provide an antistatic sheet and a method for manufacturing the same, which comprises an antistatic agent and has an embossed lower layer, thereby preventing floor contamination caused by the carbon contained in conventional lower layers and stably preventing static electricity that may be generated on floors in industrial sites such as semiconductor manufacturing plants and various offices, thereby preventing adverse effects such as damage to equipment and parts caused by static electricity.

[0011] Another object of the present invention is to provide an antistatic sheet and a manufacturing method thereof, which can prevent an increase in manufacturing costs due to the use of carbon materials by forming the lower layer of the antistatic sheet with an embossed structure, and can prevent the problem of the antistatic sheet separating from the floor surface due to a decrease in adhesive strength between the antistatic sheet and the floor surface over time.

[0012] Another object of the present invention is to provide an antistatic sheet and a manufacturing method thereof that can provide excellent antistatic effects without using a carbon or metal layer contained in conventional antistatic sheets, by imparting conductivity to a pattern layer, and without providing a separate conductive sheet layer. [Means for solving the problem]

[0013] In one embodiment of the inventive concept, an antistatic sheet is disclosed.

[0014] The antistatic sheet includes a conductive color pattern layer 300, a transparent protective layer 400 positioned on top of the conductive color pattern layer 300 to protect the surface of the conductive color pattern layer 300, a main layer 200 positioned below the conductive color pattern layer 300, and a lower layer 100 positioned below the main layer 200 and having an embossed lower surface that comes into contact with the floor.

[0015] In another embodiment of the technical concept of the present invention, a method for manufacturing an antistatic sheet is disclosed.

[0016] The method for manufacturing the antistatic sheet includes manufacturing a transparent protective layer 400, a conductive color pattern layer 300, a main layer 200, and a lower layer 100, sequentially stacking the transparent protective layer 400, the conductive color pattern layer 300, the main layer 200, and the lower layer 100, and then thermally laminating the layers to manufacture the antistatic sheet 10. The lower layer 100 is made of soft PVC and has an embossed structure with grooves 120 formed on the lower surface of the soft PVC lower layer 100. A carbon material is applied to the lower surface of the lower layer 100, and then coated using a knife coating method, so that the carbon material 140 is filled in the grooves 120.

[0017] Other specific details of the embodiments are included in the description of the invention. [Effects of the Invention]

[0018] According to various embodiments of the technical concept of the present invention, a method for manufacturing an antistatic sheet includes an antistatic agent and forms an embossed lower layer to form an antistatic sheet, thereby preventing the floor surface from being soiled by the carbon contained in the lower layer as in the conventional method, and stably preventing static electricity that may occur on the floors of industrial sites such as semiconductor manufacturing plants and various offices, thereby making it possible to manufacture an antistatic sheet that can prevent adverse effects such as damage to equipment and parts caused by static electricity.

[0019] Furthermore, the antistatic sheet according to various embodiments of the technical concept of the present invention has an embossed structure in the lower layer constituting the antistatic sheet, thereby preventing an increase in manufacturing costs due to the use of carbon material, and also preventing the problem of the antistatic sheet separating from the floor surface due to a decrease in adhesive strength between the antistatic sheet and the floor surface over time.

[0020] In addition, the antistatic sheets according to various embodiments of the technical concept of the present invention can achieve excellent antistatic effects without using a carbon or metal layer contained in conventional antistatic sheets, by imparting conductivity to the pattern layer, without providing a separate conductive sheet layer. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a cross-sectional view schematically illustrating a cross section of an antistatic sheet according to an embodiment of the technical concept of the present invention. [Figure 2] 1 is a plan view schematically illustrating a lower layer constituting an antistatic sheet according to an embodiment of the present invention. [Figure 3] 1 is a cross-sectional view schematically illustrating a cross section of a lower layer constituting an antistatic sheet according to an embodiment of the technical concept of the present invention. [Figure 4] 1 is a cross-sectional view schematically illustrating a state in which a carbon material is filled in a lower layer of an antistatic sheet according to an embodiment of the present invention; [Figure 5] 1 is a photograph showing a lower layer manufactured according to an example. [Figure 6] 1 is a photograph showing a lower layer manufactured according to a comparative example. [Figure 7] 1 is a photograph showing a resistor of a lower layer manufactured according to an embodiment. [Figure 8] 10 is a photograph showing a resistor of a lower layer manufactured according to a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0022] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An antistatic sheet according to a preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

[0023] FIG. 1 is a cross-sectional view schematically showing a cross section of an antistatic sheet according to one embodiment of the technical concept of the present invention, FIG. 2 is a plan view schematically showing a lower layer constituting an antistatic sheet according to one embodiment of the technical concept of the present invention, FIG. 3 is a cross-sectional view schematically showing a cross section of a lower layer constituting an antistatic sheet according to one embodiment of the technical concept of the present invention, and FIG. 4 is a cross-sectional view schematically showing a cross section of a state in which a carbon material is filled in the lower layer constituting an antistatic sheet according to one embodiment of the technical concept of the present invention.

[0024] 1 to 4, an antistatic sheet 10 according to one embodiment of the technical concept of the present invention includes a conductive color pattern layer 300, a transparent protective layer 400 positioned on the conductive color pattern layer 300 to protect the surface of the conductive color pattern layer 300, a main layer 200 positioned below the conductive color pattern layer 300, and a lower layer 100 positioned below the main layer 200, the lower surface of which, coming into contact with the floor, has an embossed structure.

[0025] The conductive color pattern layer 300 may be a layer containing an antistatic agent, which is a conductive material, and may be a patterned layer. The conductive color pattern layer 300 includes an underlayer 340 and a conductive pigment layer 320 located on the underlayer 340.

[0026] The base layer 340 may contain soft PVC and an antistatic agent, and the antistatic agent may be contained in a weight ratio of 0.1 to 5 parts by weight per 100 parts by weight of the total content of the soft PVC, and the base layer 340 may be formed to a thickness in the range of 0.3 to 1.0 mm.

[0027] The soft PVC (Polyvinyl Chloride) has excellent flexibility (softness) and exhibits high tensile strength and elongation, and is therefore useful for protecting the surface of an adherend from damage such as pressing and scratches.

[0028] Unlike hard boards, flexible PVC can be used in a wide range of thicknesses, from low to high. In the case of low thickness, it is widely used for various high-frequency products and as windproof vinyl, while in the case of high thickness, it is used for various pallets, covers, vinyl curtains, etc.

[0029] Furthermore, the flexible PVC is extremely flexible, transparent, chemical-resistant, and durable, and is also suitable as a lining material for plating tanks and the chemical industry. The flexible PVC can be manufactured in a variety of colors, but transparent flexible PVC is generally the most common, and gray flexible PVC is also widely available on the market.

[0030] The antistatic agent is a conductive substance that has excellent conductivity and can discharge an electric charge. As the antistatic agent, at least one selected from the group consisting of electrically conductive metal materials, carbon materials, and conductive polymers may be used.

[0031] For example, the metal material may be at least one selected from silver or copper, which have excellent conductivity; the carbon material may be at least one selected from the group consisting of carbon powder, graphene, and graphite; and the conductive polymer may be at least one selected from the group consisting of polyaniline, polypyrrol, polythiophene, polyethylene dioxythiophene, a quaternary ammonium compound, an epoxidized amine, a fatty acid ester, a sulfated wax, and a lithium amide complex.

[0032] In the present invention, the base layer 340 is made of flexible PVC. However, if rigid PVC is used, there is a risk that an antistatic agent will not be mixed in during the manufacture of the base layer 340. However, if an antistatic agent is mixed into flexible PVC as in the present invention, the antistatic agent is present on the surface of the base layer 340, and current flows along the surface of the flexible PVC, making it conductive.

[0033] Furthermore, the base layer 340 may be formed to a thickness in the range of 0.3 to 1.0 mm. However, if the thickness of the base layer 340 exceeds 1.0 mm, the soft PVC may not soften during the heat treatment process in manufacturing the base layer 340, and the antistatic agent present on the surface of the base layer 340 may be detached and difficult to transfer to the conductive pigment layer 320 described below. If the thickness of the base layer 340 is less than 0.1 mm, the physical properties of the manufactured base layer 340 may be reduced.

[0034] The conductive pigment layer 320 may be a pigment layer containing an antistatic agent to exhibit conductivity, and the conductive pigment layer 320 may be formed to a thickness in the range of 0.005 to 0.015 mm.

[0035] The conductive pigment layer 320 may be formed in a predetermined pattern by mixing an organic solvent, a binder, and a pigment to prepare a pigment solution, and then coating the pigment solution on the underlayer 340 using a gravure printing method.

[0036] That is, the conductive pigment layer 320 may be formed by preparing a pigment solution by mixing 10 to 30 parts by weight of an organic solvent, 50 to 70 parts by weight of a binder, and 1 to 10 parts by weight of a pigment, and then coating the pigment solution in a predetermined pattern on the underlayer 340 using a gravure printing method to form the underlayer 340 on which the pigment layer is printed. The underlayer 340 on which the pigment layer is printed may then be primarily dried at a temperature of 50 to 80°C, and then the underlayer 340 on which the primarily dried pigment layer is printed may be heat-treated at a temperature of 100 to 150°C to be secondarily dried, thereby forming the conductive pigment layer 320.

[0037] At this time, during the primary drying process of the base layer 340 on which the pigment layer is printed at a temperature of 50 to 80°C, a portion of the antistatic agent remaining on the surface of the base layer 340 may transfer (or migrate) to the pigment layer, thereby forming the conductive pigment layer 320.

[0038] The organic solvent may be ethanol, methanol, toluene, benzene, ethylene glycol, thinner, or a mixture thereof.

[0039] The pigment is used to impart a color, and an organic pigment may be used. For example, the organic pigment may be Carmine Pigment Red 57:1 Soluble Azo(Ba) for red, Pigment Yellow 13 Insoluble Azo for yellow, Pigment Blue (PB) (Cu-Phthalocyanine(β)) for blue, or Carbon Black (CAS.NO) for black. 1333-86-4) and the like may be used in combination, and various types of organic solvents known in the technical field may be used, such as red pigments such as anthraquinone pigments, azo pigments, and perylene pigments; blue pigments such as metal phthalocyanine pigments, indanthrone pigments, and indophenol pigments; green pigments such as chromium oxide, zinc phthalocyanine, and halogenated phthalocyanine pigments; violet pigments such as dioxazine violet and methyl violet; yellow pigments such as tetrachloroisoindolidene pigments and benzidine yellow pigments; black pigments such as titanium black, aniline black, and carbon black; as well as cyanine, magenta, and white pigments.

[0040] The binder may be used to provide adhesion to the underlayer 340, and an acrylic resin may be used as the binder.

[0041] For example, the acrylic resin may be produced by maintaining a polymerization temperature of 90 to 95°C in a polymerization reactor equipped with a stirrer, heater, cooler, and condenser required for progressing the polymerization reaction, and equipped with a nitrogen purging means for changing the oxygen atmosphere in the polymerization reactor to an inert nitrogen atmosphere and maintaining that atmosphere, by adding an acrylic monomer, a functional monomer, a phosphorus-based monomer, methacrylic acid, and a catalyst in the presence of alcohol and water, and then reacting them for 3 to 5 hours to obtain a reaction product, and then adding water and a neutralizing agent to the reaction product and dispersing it in water.

[0042] As the acrylic monomer, at least one selected from the group consisting of methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl acrylate styrene, and acrylonitrile monomer may be used.

[0043] The functional monomer may be used to improve the water resistance and adhesion to a substrate of the acrylic resin, but the functional monomer may also improve the adhesion of the acrylic resin by improving the reactivity with methacrylic acid contained in the acrylic resin and forming a network bond.

[0044] For example, the functional monomer may be at least one selected from the group consisting of 2-hydroxymethyl acrylate, 2-hydroxyethyl (meth)acrylate, glycidyl (meth)acrylate, aryl (meth)acrylate, hydroxypropyl acrylate, aryl (meth)acrylate, and hydroxypropyl acrylate, and the functional monomer may be contained in an amount of 20 to 40 parts by weight per 100 parts by weight of the acrylic monomer.

[0045] The phosphorus-based monomer may be used to improve adhesion and rust prevention, and the phosphorus-based monomer may be at least one selected from monoalkyl phosphates and dialkyl phosphates, and the phosphorus-based monomer may be included in an amount of 2 to 10 parts by weight based on 100 parts by weight of the acrylic monomer.

[0046] The methacrylic acid may be used to improve adhesiveness by polymerizing with the acrylic monomer or to induce water dispersibility by saponifying a carboxyl group, and the methacrylic acid may be included in an amount of 5 to 15 parts by weight based on 100 parts by weight of the acrylic monomer.

[0047] The catalyst may be used to open the double bond of the monomer to promote the polymerization reaction, and the catalyst may be at least one selected from the group consisting of BPO (Benzoyl Peroxide), AIBN (2,2'-Azobisisobutyronitrile), and DTBPO (Di-Tert-Butyl Peroxide). The catalyst may be included in an amount of 1 to 5 parts by weight based on 100 parts by weight of the acrylic monomer.

[0048] The neutralizing agent may be used to adjust the pH of the acrylic resin formed by polymerizing the monomer within a certain range. For example, the known neutralizing agent AMP (2-AMINO-2-METHYL-1-PROPANOL)-95 may be used as the neutralizing agent. The neutralizing agent may be contained in an amount of 5 to 10 parts by weight based on 100 parts by weight of the acrylic monomer.

[0049] In the present invention, an acrylic monomer, a functional monomer, and a phosphorus-based monomer may be used as monomers for producing the acrylic resin as described above, and the weight average molecular weight (Mw) of the acrylic resin formed by polymerizing the monomers may be 5,000 to 10,000, and the pH may be 8 to 8.5.

[0050] The Tg of the acrylic resin formed by polymerizing the monomers may be in the range of -5 to 20°C. However, if the Tg of the acrylic resin is too high, the coating film may become too strong and cracks may occur, whereas if the Tg is too low, problems may arise with drying properties. Therefore, the Tg of the acrylic resin is preferably in the range of -5 to 20°C.

[0051] The pattern formed on the base layer 340 using the gliding printing method may be manufactured in various forms known in the art, and preferably, the pattern is connected without any breaks. When the pattern is connected, the overall conductivity is improved and the surface resistance of the conductive color pattern layer 300 is reduced.

[0052] The formation of a pattern using the gravure printing method or the like in the present invention is a known technique, and for the sake of convenience and clarity of the technical idea of ​​the present invention, a detailed description thereof will be omitted.

[0053] The transparent protective layer 400 may be positioned on the conductive color pattern layer 300 to protect the surface of the conductive color pattern layer 300, and the transparent protective layer 400 may be formed to a thickness in the range of 0.1 to 0.5 mm.

[0054] In addition, the transparent protective layer 400 may be manufactured by including a transparent flexible PVC and an antistatic agent, so that the conductive color pattern layer 300 can be visualized by a user with its external color, thereby improving the aesthetics. The antistatic agent may be included in a weight ratio of 0.1 to 3 parts by weight based on 100 parts by weight of the total content of the flexible PVC.

[0055] The main body layer 200 may be located under the conductive color pattern layer 300 to attenuate external impacts applied to the antistatic sheet 10 and also attenuate static electricity generated on the antistatic sheet 10 .

[0056] The main layer 200 may contain a flexible PVC, an antistatic agent, and a plasticizer, with the weight ratio of the antistatic agent being 1 to 3 parts by weight and the plasticizer being 0.5 to 1.5 parts by weight per 100 parts by weight of the total content of the flexible PVC, and the main layer 200 may be formed to a thickness in the range of 1 to 5 mm.

[0057] The plasticizer is mixed with flexible PVC to impart elastic modulus and flexibility, while also lowering the melt viscosity to improve the processability of the flexible PVC. It may also lower the melt viscosity and glass transition temperature (Tg) to improve processability and impart various physical properties and functions such as flexibility and cold resistance to the final product. For example, the plasticizer may be at least one selected from phthalate-based plasticizers, terephthalate-based plasticizers, benzoate-based plasticizers, citric acid-based plasticizers, phosphate-based plasticizers, and adipate-based plasticizers. Preferably, an epoxy-based plasticizer, which is a stabilizer with excellent heat resistance and cold resistance, may be provided. The epoxy-based plasticizer may include, but is not limited to, epoxidized octyl stearate, epoxidized fatty acid ester, and the like.

[0058] The benzoate-based plasticizer may be, but is not limited to, 2-(2-(2-phenylcarbonyloxyethoxy)ethoxy)ethyl benzoate, glyceryl tribenzoate, trimethylolpropane tribenzoate, isononyl benzoate, 1-methyl-2-(2-phenylcarbonyloxypropoxy)ethyl benzoate, 2,2,4-trimethyl-1,3-pentanediol dibenzoate, n-hexyl benzoate, or trimethylolpropane tribenzoate.

[0059] The citrate-based plasticizer may be, but is not limited to, acetyl tributyl citrate or tributyl citrate.

[0060] The phosphate-based plasticizer may be, but is not limited to, tricresyl phosphate or tributyl phosphate.

[0061] The adipate-based plasticizer may be, but is not limited to, bis(2-ethylhexyl) adipate, dimethyl adipate, monomethyl adipate, or dioctyl adipate or diisononyl adipate.

[0062] The lower layer 100 is located below the main layer 200, and its lower surface that comes into contact with the floor surface is formed with an embossed structure. The lower layer 100 is located below the main layer 200 and comes into contact with the floor surface, fixing the antistatic sheet 10 and attenuating static electricity generated below the antistatic sheet 10.

[0063] In addition, in the present invention, the lower layer 100 is formed in an embossed structure, and the depth and size of the grooves 120 forming the embossed structure are adjusted to ensure sufficient conductivity and adhesive strength required for an antistatic sheet, and the amount of carbon material used is adjusted to prevent cost increases due to the use of carbon material, and to prevent the floor surface from being soiled by dust from the carbon material used in the lower layer 100.

[0064] The lower layer 100 is made of soft PVC, and has a groove 120 formed on the lower surface with a certain depth and size, and the groove 120 is filled with a carbon material 140. The groove 120 may be formed with a depth in the range of 0.05 to 0.2 mm, and the lower layer 100 may be formed with a thickness in the range of 0.1 to 1 mm.

[0065] In addition, the carbon material 140 filled in the groove 120 may have an antistatic effect of attenuating static electricity generated on the floor surface on which the antistatic sheet 10 is installed, and for example, the carbon material may be at least one selected from the group consisting of carbon powder, graphene, and graphite.

[0066] In addition, the lower layer 100 may be made of soft PVC, and a groove 120 may be formed on the lower surface of the lower layer 100 made of soft PVC. A carbon material may be applied to the lower layer 100 with the groove 120 formed therein, and then coated using a knife coating method, so that the carbon material 140 is filled in the groove 120.

[0067] The knife coating method refers to applying a certain amount of carbon material to one side of the lower layer 120 where the grooves 120 are formed, and then spreading it thinly to an appropriate thickness using a knife or blade.

[0068] In the present invention, one side of the lower layer 120 on which the grooves 120 are formed may be coated with a carbon material using a knife coating method, and then hot air dried at a temperature of 130 to 150°C for 1 to 3 minutes, so that the carbon material 140 is filled into the grooves 120 formed in the lower layer 120.

[0069] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing an antistatic sheet according to an embodiment of the present invention will now be described in more detail with reference to the accompanying drawings.

[0070] First, to manufacture the antistatic sheet 10 according to one embodiment of the technical concept of the present invention, the transparent protective layer 400, the conductive color pattern layer 300, the main layer 200, and the lower layer 100 may be manufactured.

[0071] The transparent protective layer 400 may be manufactured by including a transparent flexible PVC and an antistatic agent, thereby allowing the user to visualize the conductive color pattern layer 300 with its appearance color, thereby improving the aesthetics. The antistatic agent may be included in a weight ratio of 0.1 to 3 parts by weight with respect to 100 parts by weight of the total content of the flexible PVC, and the transparent protective layer 400 may be formed to a thickness in the range of 0.1 to 0.5 mm.

[0072] The conductive color pattern layer 300 may be manufactured to include an underlayer 340 and a conductive pigment layer 320 located on the underlayer 340 .

[0073] The base layer 340 may contain soft PVC and an antistatic agent, and the antistatic agent may be contained in a weight ratio of 0.1 to 5 parts by weight per 100 parts by weight of the total content of the soft PVC, and the base layer 340 may be formed to a thickness in the range of 0.3 to 1.0 mm.

[0074] In the present invention, the base layer 340 is made of flexible PVC. However, if rigid PVC is used, there is a risk that an antistatic agent will not be mixed in during the manufacture of the base layer 340. However, if an antistatic agent is mixed into flexible PVC as in the present invention, the antistatic agent is present on the surface of the base layer 340, and current flows along the surface of the flexible PVC, making it conductive.

[0075] Furthermore, the base layer 340 may be formed to a thickness in the range of 0.3 to 1.0 mm. However, if the thickness of the base layer 340 exceeds 1.0 mm, the soft PVC may not soften during the heat treatment process in manufacturing the base layer 340, and the antistatic agent present on the surface of the base layer 340 may be detached and difficult to transfer to the conductive pigment layer 320 described below. If the thickness of the base layer 340 is less than 0.1 mm, the physical properties of the manufactured base layer 340 may be reduced.

[0076] The conductive pigment layer 320 may be a pigment layer containing an antistatic agent to exhibit conductivity, and the conductive pigment layer 320 may be formed to a thickness in the range of 0.005 to 0.015 mm.

[0077] The conductive pigment layer 320 may be formed in a predetermined pattern by mixing an organic solvent, a binder, and a pigment to prepare a pigment solution, and then coating the pigment solution on the underlayer 340 using a gravure printing method.

[0078] That is, the conductive pigment layer 320 may be formed by preparing a pigment solution by mixing 10 to 30 parts by weight of an organic solvent, 50 to 70 parts by weight of a binder, and 1 to 10 parts by weight of a pigment, and then coating the pigment solution in a predetermined pattern on the underlayer 340 using a gravure printing method to form the underlayer 340 on which the pigment layer is printed. The underlayer 340 on which the pigment layer is printed may then be primarily dried at a temperature of 50 to 80°C, and then the underlayer 340 on which the primarily dried pigment layer is printed may be heat-treated at a temperature of 100 to 150°C to be secondarily dried, thereby forming the conductive pigment layer 320.

[0079] At this time, during the primary drying process of the base layer 340 on which the pigment layer is printed at a temperature of 50 to 80°C, a portion of the antistatic agent remaining on the surface of the base layer 340 may transfer (or migrate) to the pigment layer, thereby forming the conductive pigment layer 320.

[0080] The main layer 200 may contain a flexible PVC, an antistatic agent, and a plasticizer, with the weight ratio of the antistatic agent being 1 to 3 parts by weight and the plasticizer being 0.5 to 1.5 parts by weight per 100 parts by weight of the total content of the flexible PVC, and the main layer 200 may be formed to a thickness in the range of 1 to 5 mm.

[0081] The lower layer 100 is formed in an embossed structure, and the depth and size of the grooves 120 that form the embossed structure are adjusted to ensure sufficient conductivity and adhesive strength required for an antistatic sheet, and the amount of carbon material used is adjusted to prevent cost increases due to the use of carbon material and to prevent floor surface contamination due to dust from the carbon material used in the lower layer 100.

[0082] The lower layer 100 is made of soft PVC, and has a groove 120 formed on the lower surface with a certain depth and size, and the groove 120 is filled with a carbon material 140. The groove 120 may be formed with a depth in the range of 0.05 to 0.2 mm, and the lower layer 100 may be formed with a thickness in the range of 0.1 to 1 mm.

[0083] In addition, the lower layer 120 may be made of soft PVC, and a groove 120 may be formed on the lower surface of the lower layer 120 made of soft PVC. A carbon material may be applied to the lower layer 120 with the groove 120 formed therein, and then coated using a knife coating method, so that the carbon material 140 is filled in the groove 120.

[0084] The knife coating method refers to applying a certain amount of carbon material to one side of the lower layer 120 where the grooves 120 are formed, and then spreading it thinly to an appropriate thickness using a knife or blade.

[0085] In the present invention, one side of the lower layer 120 on which the grooves 120 are formed may be coated with a carbon material using a knife coating method, and then hot air dried at a temperature of 130 to 150°C for 1 to 3 minutes, so that the carbon material 140 is filled into the grooves 120 formed in the lower layer 120.

[0086] Next, the transparent protective layer 400, the conductive color pattern layer 300, the main body layer 200, and the lower layer 100 are sequentially laminated, and then the antistatic sheet 10 may be manufactured by thermal lamination.

[0087] For example, the transparent protective layer 400, the conductive color pattern layer 300, the main body layer 200, and the lower layer 100 are thermally laminated at a temperature of 120 to 150°C and a pressure of 40 to 60 kg / cm. 2 Alternatively, the lamination may be performed by a flat pressing process under the conditions of

[0088] Hereinafter, an antistatic sheet according to an embodiment of the technical concept of the present invention will be described in detail with reference to the accompanying drawings. The following examples are for illustrative purposes only, and the present invention is not limited to the following examples, and may be modified and changed in various ways.

[0089] <Example> First, a flexible PVC was prepared, and then a groove was formed on one surface of the flexible PVC.

[0090] Next, the flexible PVC with the grooves formed therein was coated with carbon powder using a knife coating method, and then dried with hot air at a temperature of 140°C for 2 minutes to produce a lower layer with the grooves filled with carbon powder.

[0091] <Comparative Example> A flexible PVC was prepared, and then one side of the flexible PVC was coated with carbon powder by gravure printing, followed by drying with hot air at a temperature of 140°C for 2 minutes, thereby producing a lower layer in which one side of the flexible PVC was coated with carbon powder.

[0092] Resistance measurement of the bottom layer The resistance of the lower layer manufactured according to the example and comparative example was measured.

[0093] FIG. 5 is a photograph showing the lower layer manufactured according to the example, FIG. 6 is a photograph showing the lower layer manufactured according to the comparative example, FIG. 7 is a photograph showing the resistance of the lower layer manufactured according to the example, and FIG. 8 is a photograph showing the resistance of the lower layer manufactured according to the comparative example.

[0094] 5 to 8, the resistance of the lower layer manufactured according to the embodiment is 10 4 OHMS (Ω), and the resistance of the lower layer in the comparative example is 10 3 It was OHMS(Ω).

[0095] From this, it can be seen that by forming an embossed structure as in the example and coating the grooves of the embossed structure with a carbon material by knife coating to form a lower layer, it is possible to ensure electrical conductivity similar to that of the lower layer of a conventional antistatic sheet, as well as ensure adhesive strength with the floor surface, and prevent the floor surface from becoming dirty due to the carbon material.

Claims

1. a conductive color pattern layer 300; a transparent protective layer 400 positioned on the conductive color pattern layer 300 to protect the surface of the conductive color pattern layer 300; a main body layer 200 located under the conductive color pattern layer 300; and a lower layer (100) located below the main layer (200) and having an embossed lower surface that contacts the floor.

2. 2. The antistatic sheet according to claim 1, wherein the lower layer (120) is made of soft PVC and has grooves (120) formed on the lower surface of the lower layer (120) made of soft PVC.

3. 3. The antistatic sheet according to claim 2, wherein a carbon material is applied to the lower surface of the lower layer (100) and then coated using a knife coating method, so that the carbon material (140) is filled in the grooves (120).

4. 3. The antistatic sheet according to claim 2, wherein the carbon material is coated on one side of the lower layer 120 in which the grooves 120 are formed using a knife coating method, and then dried with hot air at a temperature of 130 to 150°C for 1 to 3 minutes, thereby filling the carbon material 140 into the grooves 120 formed in the lower layer 120.

5. Manufacture a transparent protective layer 400, a conductive color pattern layer 300, a main body layer 200, and a lower layer 100; The transparent protective layer 400, the conductive color pattern layer 300, the main body layer 200, and the lower layer 100 are sequentially laminated, and then thermally laminated to produce the antistatic sheet 10. a lower layer (100) made of soft PVC, an embossed structure in which grooves (120) are formed on a lower surface of the lower layer (100) made of soft PVC; a carbon material is applied to the lower surface of the lower layer (100), and then coated using a knife coating method, so that the carbon material (140) is filled in the grooves (120).

6. The conductive color pattern layer 300 is manufactured to include an underlayer 340 and a conductive pigment layer 320 located on the underlayer 340, 6. The method for manufacturing an antistatic sheet according to claim 5, wherein the conductive pigment layer 320 is formed by preparing a pigment solution by mixing 10 to 30 parts by weight of an organic solvent, 50 to 70 parts by weight of a binder, and 1 to 10 parts by weight of a pigment, coating the pigment solution on the underlayer 340 in a predetermined pattern using a gravure printing method to form the underlayer 340 on which the pigment layer is printed, primarily drying the underlayer 340 on which the pigment layer is printed at a temperature of 50 to 80°C, and then heat-treating the primarily dried underlayer 340 on which the pigment layer is printed at a temperature of 100 to 150°C to perform secondary drying, thereby forming the conductive pigment layer 320.

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