Resin sheets and building material laminates

Abstract

To provide a resin sheet which offers suitable secondary workability without losing functions such as an antibacterial property.SOLUTION: A resin sheet includes a base material, a first functional layer which is provided on one main surface of the base material and contains a thermoplastic resin and a functional agent, and a second functional layer which is provided on the surface of the first functional layer and contains a cationic water-soluble polymer, wherein the functional agent contains at least one of calcium hydroxide and a metal carrier, and the thickness of the second functional layer is 0.1 μm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to resin sheets and building material laminates. [Background technology]

[0002] Resin sheets are widely used in various fields such as household goods, building materials, and agricultural products. To impart various functions to resin sheets using functional agents with properties appropriate to their intended use, such as antibacterial properties, methods such as coating, which involves applying a coating layer containing the functional agent to the surface of the resin sheet, and mixing, which involves directly adding the functional agent to the resin constituting the sheet during molding, are being investigated.

[0003] While coating methods make it easy to impart functionality even with small amounts of functional agents, there are concerns about low environmental stability, such as water resistance, moisture resistance, and weather resistance, because the coating is exposed to the surface. While the compounding method offers excellent environmental stability, it necessitates increasing the amount of additives to achieve the desired functionality, raising concerns about its impact on printability and secondary processing properties such as adhesion to other films, making it difficult to achieve a quantitative balance.

[0004] Patent Document 1 describes a resin composition containing calcium hydroxide material as an antibacterial agent. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-120763 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, the resin sheet produced from the resin composition described in Patent Document 1 had room for improvement in terms of secondary processing properties such as adhesion. An object of the present invention is to provide a resin sheet suitable for secondary processing without losing functions such as antibacterial properties.

Means for Solving the Problems

[0007] The present invention relates to the following resin sheet. 〔1〕A resin sheet comprising a base material, a first functional layer provided on one main surface of the base material and containing a thermoplastic resin and a functional agent, and a second functional layer provided on the surface of the first functional layer and containing a cationic water-soluble polymer, wherein the functional agent contains at least one of calcium hydroxide and a metal carrier, and the resin sheet has a thickness of the second functional layer of 0.1 μm or less.

Advantages of the Invention

[0008] According to the present invention, it is possible to provide a resin sheet suitable for secondary processing without losing functions such as antibacterial properties.

Brief Description of the Drawings

[0009] [Figure 1] FIG. 1 is a cross-sectional view showing an example of a resin sheet according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing an example of a resin sheet according to another embodiment of the present invention. [Figure 3] FIG. 3 is a cross-sectional view showing an example of a building material laminate according to another embodiment of the present invention.

Mode for Carrying Out the Invention

[0010] Hereinafter, the resin sheet and the building material laminate according to the embodiment of the present invention will be described in detail. The following is an example (representative example) of the present invention, and the present invention is not limited thereto.

[0011] <Resin Sheet> FIG. 1 shows a cross-sectional view of a resin sheet according to an embodiment of the present invention. The resin sheet 1 in FIG. 1 has a base material 10, a first functional layer 11 provided on one main surface of the base material 10, and a second functional layer 12 provided on the surface of the first functional layer 11.

[0012] FIG. 2 shows a cross-sectional view of a resin sheet according to another embodiment of the present invention. The resin sheet 1 in FIG. 2 has a base material 10, a first functional layer 11 provided on one main surface of the base material 10, and a second functional layer 12 provided on the surface of the first functional layer 11, and has a third functional layer 13 provided on the other main surface of the base material 10 and a fourth functional layer 14 provided on the surface of the third functional layer 13.

[0013] <Base material> The base material is used to impart strength to the resin sheet and is preferably made of a thermoplastic resin film. By using a thermoplastic resin film as the base material, mechanical strength such as firmness, water resistance, chemical resistance, and opacity if necessary can be imparted to the resin sheet or a printed matter using the resin sheet.

[0014] The thermoplastic resin used as the base material is not particularly limited, and examples include polyethylene resins, polypropylene resins, polybutene, polyolefin resins such as 4-methyl-1-pentene (co)polymer; functional group-containing olefin resins such as ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid copolymer, metal salts (ionomers) of ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylate alkyl ester copolymer (preferably with 1 to 8 carbon atoms in the alkyl group), maleic acid-modified polyethylene, maleic acid-modified polypropylene; aromatic polyesters (polyethylene terephthalate Examples include polyester resins such as polybutylene terephthalate, polyethylene naphthalate, etc., and aliphatic polyesters (polybutylene succinate, polylactic acid, etc.); polyamide resins such as nylon-6, nylon-6,6, nylon-6,10, and nylon-6,12; styrene resins such as syndiotactic polystyrene, atactic polystyrene, acrylonitrile-styrene (AS) copolymer, styrene-butadiene (SBR) copolymer, and acrylonitrile-butadiene-styrene (ABS) copolymer; polyvinyl chloride resin; polycarbonate resin; and polyphenylene sulfide. Two or more of these resins can also be used in mixtures.

[0015] Among these, polyolefin resins or polyester resins are preferred due to their high water resistance and transparency, polypropylene resins are more preferred among polyolefin resins, and polyethylene terephthalate is even more preferred among polyester resins.

[0016] The substrate may contain fillers to adjust its rigidity, whiteness, and opacity. Examples of fillers include inorganic fillers and organic fillers, which can be used alone or in combination. When a substrate containing fillers is stretched, numerous fine pores with the fillers as nuclei can be formed inside the substrate, thereby achieving whiteness, opacity, and weight reduction.

[0017] Examples of inorganic fillers include heavy calcium carbonate, light calcium carbonate, calcined clay, talc, diatomaceous earth, titanium dioxide, zinc oxide, barium sulfate, silicon dioxide, magnesium oxide, and inorganic particles obtained by surface treatment of these with fatty acids, polymer surfactants, antistatic agents, etc. Among these, heavy calcium carbonate, light calcium carbonate, calcined clay, or talc are preferred because they have good moldability of pores and are inexpensive. From the viewpoint of improving whiteness and opacity, titanium dioxide, zinc oxide, or barium sulfate are preferred.

[0018] While there are no particular limitations on the organic filler, it is preferable that the organic filler is immiscible with the thermoplastic resin, has a melting point or glass transition temperature higher than that of the thermoplastic resin, and is finely dispersed under the melt-kneading conditions of the thermoplastic resin. For example, when the thermoplastic resin is a polyolefin resin, examples of organic fillers include organic particles such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polystyrene, polyamide, polycarbonate, polyethylene sulfide, polyphenylene sulfide, polyimide, polyether ketone, polyether ether ketone, polymethyl methacrylate, poly-4-methyl-1-pentene, homopolymers of cyclic olefins, and copolymers of cyclic olefins and ethylene. Alternatively, a fine powder of a thermosetting resin such as melamine resin may be used, and it is also preferable to crosslink and insolubilize the thermoplastic resin. The melting point (°C) and glass transition temperature (°C) of the resin can be measured by differential scanning calorimetry (DSC).

[0019] Inorganic fillers and organic fillers may be selected from the above and used individually, or two or more may be used in combination. When combining two or more, a combination of inorganic fillers and organic fillers is also acceptable.

[0020] From the viewpoint of ease of mixing with thermoplastic resin, it is preferable that the average particle size of the inorganic filler and organic filler be large. Furthermore, from the viewpoint of reducing the likelihood of problems such as sheet tearing during stretching and a decrease in the strength of the substrate when stretching is used to create voids inside the material to improve opacity and printability, it is preferable that the average particle size of the inorganic filler and organic filler be small. Specifically, the average particle size of the inorganic filler and organic filler is preferably 0.01 μm or more, more preferably 0.1 μm or more, and even more preferably 0.5 μm or more. Furthermore, the average particle size of the inorganic filler and organic filler is preferably 30 μm or less, more preferably 20 μm or less, and even more preferably 15 μm or less.

[0021] The average particle size of inorganic and organic fillers can be determined by observing the cross-section of the substrate with an electron microscope, measuring the average of the maximum diameters of at least 10 particles, and then dispersing them in a thermoplastic resin by melt kneading and dispersion.

[0022] The filler content in the substrate is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, from the viewpoint of imparting opacity to the substrate. From the viewpoint of providing rigidity to the base material and improving the handling of the resin sheet, the filler content in the base material is preferably 45% by mass or less, more preferably 40% by mass or less, and even more preferably 35% by mass or less.

[0023] The substrate may optionally contain known additives as needed. Examples of known additives include antioxidants, light stabilizers, ultraviolet absorbers, crystal nucleating agents, plasticizers, filler dispersants, slip agents such as fatty acid amides, antiblocking agents, dyes, pigments, mold release agents, and flame retardants.

[0024] The substrate may have a single-layer structure or a multi-layer structure. The thickness of the base material is preferably 30 μm or more, and more preferably 50 μm or more, as this makes it easier to obtain sufficient mechanical strength. Furthermore, the thickness of the base material is preferably 500 μm or less, and more preferably 300 μm or less, as this reduces the weight of the resin sheet and improves handling.

[0025] When the substrate has internal voids, the porosity, which represents the proportion of voids in the substrate, is preferably 10% or more, more preferably 12% or more, even more preferably 15% or more, and particularly preferably 20% or more, from the viewpoint of obtaining opacity. From the viewpoint of maintaining mechanical strength, the porosity is preferably 45% or less, more preferably 44% or less, even more preferably 42% or less, and particularly preferably 40% or less.

[0026] Porosity can be determined from the area percentage occupied by voids in a specific region of the cross-section of a substrate observed with an electron microscope. Specifically, a portion of the substrate is cut out, embedded in epoxy resin and solidified, then cut perpendicular to the surface direction of the substrate using a microtome, and attached to an observation sample stage so that the cut surface becomes the observation surface. Gold or gold-palladium is deposited on the observation surface, and voids are observed with an electron microscope at a magnification of any suitable size (e.g., 500x to 3000x), and the observed region is captured as image data. The obtained image data is processed using an image analysis device to determine the area percentage (%) of the void portion, which can then be used as the porosity (%). In this case, the porosity can be calculated by averaging the measured values ​​from 10 or more observation points.

[0027] <First functional layer> In a resin sheet according to an embodiment of the present invention, the first functional layer is provided on one main surface of the substrate and contains a thermoplastic resin and a functional agent. By having the first functional layer containing the functional agent in the resin sheet, various functions such as antibacterial properties can be imparted to the resin sheet. Furthermore, by including the functional agent in the resin (the functional agent is kneaded into the resin), the environmental stability of the resin sheet can be improved. In addition, since the second functional layer, which will be described later, is provided on the surface of the first functional layer, even if the amount of functional agent in the first functional layer is increased to improve functionality, it is possible to prevent the functional agent from affecting the adhesion and printability of the resin sheet, and a resin sheet with excellent secondary processability can be obtained.

[0028] The thermoplastic resin constituting the first functional layer is not particularly limited as long as it does not impair the effects of the present invention, and a thermoplastic resin similar to that of the substrate can be used. Among thermoplastic resins, polyolefin resins or functional group-containing olefin resins are preferred from the viewpoint of excellent processability and water resistance, and polyolefin resins are more preferred. Among polyolefin resins, polyethylene resins or polypropylene resins are preferred from the viewpoint of chemical resistance, processability and low cost.

[0029] Examples of polyolefin resins include polyethylene resins (low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, low-crystalline or amorphous ethylene-α-olefin copolymers, ethylene-cyclic olefin copolymers, etc.), polypropylene resins (crystalline polypropylene, low-crystalline polypropylene, amorphous polypropylene, propylene-ethylene copolymers (random copolymers or block copolymers, etc.), propylene-α-olefin copolymers, propylene-ethylene-α-olefin copolymers, etc.), polybutene, 4-methyl-1-pentene(co)polymers (poly(4-methyl-1-pentene), 4-methyl-1-pentene-α-olefin copolymers, etc.). The α-olefin is not particularly limited as long as it can copolymerize with ethylene, propylene, and 4-methyl-1-pentene, and examples include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, etc. Examples of functional group-containing olefin resins include ethylene-(meth)acrylate ethyl copolymer, ethylene-(meth)acrylate methyl copolymer, ethylene-(meth)acrylate n-butyl copolymer, ethylene-vinyl acetate copolymer, maleic acid-modified polyethylene, and maleic acid-modified polypropylene. These can be used individually or in combination.

[0030] From the viewpoint of effectively obtaining the function provided by the first functional layer, the thickness of the first functional layer is preferably 1 μm or more, and more preferably 2 μm or more. Furthermore, from the viewpoint of reducing the weight of the resin sheet itself and improving handling, the thickness of the first functional layer is preferably 200 μm or less. By thinning the first functional layer, it is possible to provide a resin sheet that does not easily impair the functionality of the substrate (such as opacity) and can be adjusted to a thickness and stiffness suitable for label applications and secondary processing.

[0031] <Functional Agents> The functional agent is not limited to any agent that has the property of imparting various functions to the resin sheet. For example, a functional agent having one or more functions selected from antibacterial, antifungal, and antiviral properties is preferred. Furthermore, one functional agent may be used alone, or two or more may be used together. In this specification, “antibacterial” means, for example, sterilization, damage, or prevention of growth of bacteria, fungi. “Antifungal” means, for example, prevention of the growth or proliferation of mold. “Antiviral” means, for example, inactivation of viruses.

[0032] The functional agent comprises at least one of calcium hydroxide and a metal support. The functional agent may be used alone or in combination of two or more. Calcium hydroxide and the metal support have antibacterial, antifungal, and antiviral properties.

[0033] From the viewpoint of making the first functional layer a porous layer, a calcium hydroxide-supported material is preferred as the calcium hydroxide. Examples of calcium hydroxide-supported materials include seashell powder and calcined seashell powder.

[0034] A metal carrier is composed of a metal and a support that holds the metal. Examples of metals include gold, silver, copper, mercury, zinc, iron, lead, bismuth, titanium, tin, and nickel. The form of the metal is not particularly limited and can be in the form of metal particles, metal ions, and metal salts (including metal complexes). In particular, from the viewpoint of obtaining better antibacterial, antiviral, or antifungal properties, it is preferable to include gold, silver, or copper as the metal. Examples of supporters include inorganic oxides (e.g., zeolite (crystalline aluminosilicate), silica gel, silicates of clay minerals, glass (including water-soluble glass), zirconium phosphate, and calcium phosphate), activated carbon, metal carriers, and organometallic materials. From the viewpoint of obtaining excellent antibacterial, antiviral, or antifungal properties, it is preferable that the metal carrier be a silver carrier. The silver in the silver support is preferably, specifically, silver salts such as silver nitrate, silver chloride, silver sulfate, silver lactate, and silver acetate; silver complexes such as silver ammonia complexes, silver chloro complexes, and silver thiosulfate complexes; silver particles; or silver ions.

[0035] The content of the functional agent in the first functional layer is preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 3% by mass or more, and particularly preferably 5% by mass or more. The content of the functional agent in the first functional layer is preferably 30% by mass or less, more preferably 28% by mass or less, and even more preferably 25% by mass or less. A functional agent content of 1% by mass or more makes it easier for the antibacterial and other functions of the first functional layer to be expressed even on top of the second functional layer. Furthermore, a content of 30% by mass or less is preferable because it improves dispersibility in thermoplastic resins.

[0036] When calcium hydroxide is used as a functional agent, the calcium hydroxide content in the first functional layer is preferably 1% by mass or more, more preferably 2% by mass or more, particularly preferably 5% by mass or more, preferably 30% by mass or less, more preferably 20% by mass or less, and particularly preferably 15% by mass or less. In the case of a calcium hydroxide support, it is preferable that the value converted to the content of calcium hydroxide itself falls within the above range. When a metal support is used as a functional agent, the content of the metal support in the first functional layer is preferably 1% by mass or more, more preferably 2% by mass or more, particularly preferably 3% by mass or more, preferably 10% by mass or less, more preferably 8% by mass or less, and particularly preferably 7% by mass or less.

[0037] The first functional layer is preferably a stretched layer. The first functional layer being a stretched layer containing the functional agent, and possibly further containing at least one of an inorganic filler and an organic filler in addition to the functional agent, can become a stretched porous layer. Having a porous structure in the first functional layer is preferable because it allows the functional agent to be more easily exposed on the surface of the first functional layer, thus facilitating the exertion of its effects. Furthermore, because the first functional layer is a stretched layer, its surface is roughened, increasing the contact area of ​​the functional agent, thus effectively exhibiting functions such as antibacterial properties.

[0038] The inorganic and organic fillers are preferably the same as those used in the above-mentioned substrate.

[0039] When the first functional layer contains inorganic fillers or organic fillers, their content is preferably 10 to 60% by mass, and more preferably 15 to 50% by mass. When the functional agent is a calcium hydroxide support or a metal support, and the first functional layer contains inorganic fillers separately from the functional agent, the inorganic filler content refers to the total content of the calcium hydroxide support and the metal support combined.

[0040] The first functional layer may contain other components as long as they do not impair the effects of the present invention. Examples of other components include the additives listed for the base material.

[0041] <Second functional layer> In a resin sheet according to an embodiment of the present invention, the second functional layer is provided on the surface of the first functional layer, contains a cationic water-soluble polymer, and has a thickness of 0.1 μm or less. The first functional layer is usually placed on the outermost surface of the resin sheet due to its functional properties such as antibacterial properties. However, in the resin sheet according to the embodiment of the present invention, the first functional layer is covered by the second functional layer and is not placed on the outermost surface of the resin sheet. However, by including a cationic water-soluble polymer in the second functional layer and keeping its thickness below a certain level, the expression of functions such as antibacterial properties is not inhibited even if the first functional layer is not on the outermost surface, and furthermore, surface performance, i.e., secondary processability, can be imparted to the resin sheet by the second functional layer.

[0042] <Cationic water-soluble polymer> The inclusion of a cationic water-soluble polymer in the second functional layer makes it less likely for the first functional layer to inhibit the expression of antibacterial and other functions. The water solubility of the cationic water-soluble polymer is sufficient to be adequate when preparing the coating solution for forming the second functional layer, such that the aqueous medium containing the cationic water-soluble polymer becomes a solution.

[0043] Examples of cationic water-soluble polymers include (meth)acrylic polymers or ethyleneimine polymers having an amino group or ammonium salt structure, water-soluble polymers having a phosphonium salt structure, vinyl polymers that are cationized by modification of water-soluble polymers such as polyvinylpyrrolidone and polyvinyl alcohol, and one of these can be used alone or in combination of two or more. Among these, (meth)acrylic polymers or ethyleneimine polymers having an amino group or ammonium salt structure are preferred from the viewpoint of ink or toner transferability and adhesion to the second functional layer, and (meth)acrylic polymers or ethyleneimine polymers having an amino group are more preferred.

[0044] From a safety standpoint, (meth)acrylic polymers or ethyleneimine polymers having an amino group or ammonium salt structure are preferably having primary to tertiary amino groups or primary to tertiary ammonium salt structures, more preferably having secondary to tertiary amino groups or secondary to tertiary ammonium salt structures, and even more preferably having a tertiary amino group or tertiary ammonium salt structure. Furthermore, from the viewpoint of obtaining a resin with a high degree of crosslinking through reaction with a silane coupling agent described later, and obtaining high adhesion between the ink or toner and the second functional layer, primary to tertiary amino groups or primary to tertiary ammonium salt structures are preferred, primary to secondary amino groups or primary to secondary ammonium salt structures are more preferred, and primary amino groups or primary ammonium salt structures are even more preferred.

[0045] In particular, ethyleneimine polymers are preferred because they have high affinity for inks or toners used in various printing methods, especially UV-curable inks used in flexographic printing, thus improving adhesion between the second functional layer and the ink. Examples of ethyleneimine polymers include polyethyleneimine, poly(ethyleneimine-urea), ethyleneimine adducts of polyamine polyamides, alkyl modified versions thereof, cycloalkyl modified versions, aryl modified versions, allyl modified versions, aralkyl modified versions, benzyl modified versions, cyclopentyl modified versions, cyclic aliphatic hydrocarbon modified versions, glycidol modified versions, and hydroxides thereof. Examples of modifying agents for obtaining modified products include methyl chloride, methyl bromide, n-butyl chloride, lauryl chloride, stearyl iodide, oleyl chloride, cyclohexyl chloride, benzyl chloride, allyl chloride, and cyclopentyl chloride.

[0046] The weight-average molecular weight of the cationic water-soluble polymer is preferably 1,000 or more, more preferably 10,000 or more, even more preferably 20,000 or more, and particularly preferably 25,000 or more, from the viewpoint of improving adhesion to the first functional layer and adhesion to inks, etc. On the other hand, the weight-average molecular weight is preferably 1,000,000 or less, and more preferably 500,000 or less. The weight-average molecular weight and number-average molecular weight of the polymer can be obtained by converting the values ​​measured by GPC (Gel Permeation Chromatography) to polystyrene equivalents.

[0047] The second functional layer preferably contains a resin which is a reaction product of a cationic water-soluble polymer and a silane coupling agent. By reacting with the silane coupling agent, adhesion to the first functional layer can be improved. The silane coupling agent has functional groups that are highly reactive with organic materials, and it is presumed that these functional groups crosslink the thermoplastic resin of the first functional layer with the cationic water-soluble polymer, thereby improving adhesion to the first functional layer and preventing moisture from penetrating between the first and second functional layers. This is presumed to suppress peeling of the second functional layer and, consequently, peeling of ink or toner from printed materials, thereby improving abrasion resistance. Furthermore, it is presumed that the silane coupling agent crosslinks cationic water-soluble polymers to form a network structure, and this network structure improves the transferability and adhesion of ink or toner. In addition, it is presumed that the silane coupling agent crosslinks with the cationic water-soluble polymer, increasing the molecular weight of the hydrophilic component (polar resin component) of the cationic water-soluble polymer, thereby improving water resistance. Furthermore, even if the second functional layer contains a reaction product of a cationic water-soluble polymer and a silane coupling agent, it may also contain an unreacted portion of the cationic water-soluble polymer.

[0048] Silane coupling agents may be included in the second functional layer as unreacted components that do not form a reaction product with the cationic polymer. Specific examples of usable silane coupling agents include epoxy-based silane coupling agents, vinyl-based silane coupling agents, (meth)acrylic-based silane coupling agents, amino-based silane coupling agents, ureido-based silane coupling agents, mercapto-based silane coupling agents, isocyanate-based silane coupling agents, and the like.

[0049] The content of cationic water-soluble polymer components in the second functional layer (total amount of unreacted material and material reacted with the silane coupling agent) is preferably 30 to 100% by mass. The content of cationic water-soluble polymer components in the second functional layer (total amount of unreacted material and material reacted with the silane coupling agent) is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 75% by mass or more, preferably 100% by mass or less, more preferably 95% by mass or less, even more preferably 90% by mass or less, and particularly preferably 80% by mass or less. Having a cationic water-soluble polymer content of 30% by mass or more makes it easier to obtain functions such as mold resistance from the first functional layer.

[0050] When the second functional layer contains an ethyleneimine polymer, the content of the ethyleneimine polymer component (total amount of unreacted material and material reacted with the silane coupling agent) is preferably 30 to 100% by mass. The content of the ethyleneimine polymer component in the second functional layer (total amount of unreacted material and material reacted with the silane coupling agent) is preferably 30% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, preferably 100% by mass or less, more preferably 80% by mass or less, even more preferably 60% by mass or less, and particularly preferably 50% by mass or less. Having an ethyleneimine polymer content of 30% by mass or more improves the adhesion between the second functional layer and the ink.

[0051] When the second functional layer contains a silane coupling agent, the content of the silane coupling agent component (total amount of unreacted and reacted portion) is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 20 parts by mass or more, per 100 parts by mass of the cationic polymer component (total amount of unreacted and reacted portion) in the second functional layer. Furthermore, the content of the silane coupling agent component (total amount of unreacted and reacted portion) in the second functional layer is preferably 100 parts by mass or less, more preferably 50 parts by mass or less, and even more preferably 30 parts by mass or less, per 100 parts by mass of the cationic polymer component (total amount of unreacted and reacted portion) in the second functional layer.

[0052] Furthermore, when the second functional layer contains a silane coupling agent, the content of the silane coupling agent component (total amount of unreacted and reacted portion) is preferably 0.1% by mass or more, more preferably 1% by mass or more, and even more preferably 3% by mass or more, relative to the total mass of the second functional layer. In addition, the content of the silane coupling agent component (total amount of unreacted and reacted portion) in the second functional layer is preferably 20% by mass or less, more preferably 18% by mass or less, and even more preferably 15% by mass or less, relative to the total mass of the second functional layer.

[0053] By keeping the amount of silane coupling agent in the second functional layer within the above range, the amount of unreacted silane coupling agent remaining in the second functional layer can be suppressed. This results in the second functional layer having an appropriate hardness, allowing it to follow the bending of the resin sheet and preventing cracking of the second functional layer. In addition, keeping the amount of silane coupling agent within the above range suppresses the amount of unreacted cationic polymer remaining, resulting in excellent water resistance of the second functional layer.

[0054] <Antistatic agent> The second functional layer preferably contains an antistatic agent from the viewpoint of improving surface resistivity and making it easier to obtain antistatic properties. Among antistatic agents, polymer-type antistatic agents are preferred from the viewpoint of reducing surface contamination due to bleed-out. The polymer-type antistatic agent is not particularly limited, and cationic, anionic, amphoteric, or nonionic antistatic agents can be used, either individually or in combination of two or more. When the second functional layer contains a cationic polymer-type antistatic agent, the antistatic agent is included as a cationic water-soluble polymer.

[0055] Examples of cationic antistatic agents include those having an ammonium salt structure, a phosphonium salt structure, and the like. Examples of anionic antistatic agents include those having the structure of an alkali metal salt (lithium salt, sodium salt, potassium salt, etc.) such as sulfonic acid, phosphoric acid, or carboxylic acid. Anionic antistatic agents may also be those having the structure of an alkali metal salt such as acrylic acid, methacrylic acid, or (anhydride) maleic acid in their molecular structure.

[0056] Examples of amphoteric antistatic agents include those containing both cationic and anionic structures within the same molecule. Betaine-type antistatic agents are another example of amphoteric antistatic agents. Nonionic antistatic agents include ethylene oxide polymers having alkylene oxide structures, polymers containing ethylene oxide polymerization components in their molecular chains, and others. Other antistatic agents include polymer-type antistatic agents containing boron in their molecular structure.

[0057] Among the polymer-type antistatic agents, cationic antistatic agents are preferred, nitrogen-containing polymer-type antistatic agents are more preferred, antistatic agents having a quaternary ammonium salt structure are even more preferred, and acrylic resins having a quaternary ammonium salt structure are particularly preferred. As polymer-type antistatic agents, commercially available products such as Saftomer ST-1000, ST-1100, and ST-3200 (product names) manufactured by Mitsubishi Chemical Corporation can be used. As a polymer-type antistatic agent, a compound that reacts with the silane coupling agent may be used, or a compound that does not react may be used. However, from the viewpoint of easily exhibiting antistatic performance, a compound that does not react with the silane coupling agent is preferred.

[0058] When the second functional layer contains an antistatic agent, the antistatic agent content is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more, based on the total mass of the second functional layer. Furthermore, the antistatic agent content in the second functional layer is preferably 80% by mass or less, more preferably 60% by mass or less, even more preferably 40% by mass or less, and particularly preferably 30% by mass or less, based on the total mass of the second functional layer.

[0059] The second functional layer may optionally contain other auxiliary components such as crosslinking accelerators, antiblocking agents, pH adjusters, and defoaming agents. Examples of crosslinking accelerators include phosphoric acid, sulfuric acid, citric acid, and succinic acid.

[0060] <Inorganic filler> The inorganic filler content in the second functional layer is 9 parts by mass or less per 100 parts by mass of cationic water-soluble polymer. That is, it contains no inorganic filler, or if it does, its content is 9 parts by mass or less. By having an inorganic filler content of 9 parts by mass or less, it prevents white spots in the printed area caused by irregularities in the second functional layer due to the inorganic filler, and makes it easier to obtain a high ink transfer rate. From a similar viewpoint, the inorganic filler content in the second functional layer is more preferably 5 parts by mass or less per 100 parts by mass of cationic water-soluble polymer, and even more preferably 3 parts by mass or less.

[0061] <Thermoplastic resin particles> It is preferable that the second functional layer does not contain thermoplastic resin particles. Thermoplastic resin particles refer to particles derived from an emulsion of a thermoplastic resin, such as an olefin copolymer, dispersed in the dispersion medium in the coating liquid for forming the second functional layer. By not including thermoplastic resin particles in the second functional layer, it is possible to obtain recording paper with excellent appearance, such as gloss and transparency. From a similar viewpoint, the content of thermoplastic resin particles in the second functional layer is more preferably 5 parts by mass or less, and even more preferably 3 parts by mass or less, per 100 parts by mass of cationic water-soluble polymer.

[0062] The thickness of the second functional layer is 0.1 μm or less, preferably 0.09 μm or less, and more preferably 0.08 μm or less. Because the second functional layer is very thin, at 0.1 μm or less, it does not inhibit the function of the first functional layer, making it easier for the function to manifest and facilitating secondary processability of the resin sheet. From the viewpoint of stably forming a uniform second functional layer, the thickness of the second functional layer is preferably 0.01 μm or more, more preferably 0.02 μm or more, and even more preferably 0.03 μm or more.

[0063] <Third functional layer> The resin sheet according to the embodiment of the present invention may have a third functional layer on the other main surface of the substrate. Preferably, the third functional layer is the same as the first functional layer described above. Having a layer containing a functional agent on the other main surface is useful in applications where antibacterial properties or the like are required on the other main surface as well. For example, when a resin sheet according to an embodiment of the present invention is used in a building material laminate described later, it is sufficient for functions such as antibacterial properties to be present on one main surface side (first functional layer side), and there is little need to impart functions to the other main surface side (third functional layer side) because the resin sheet is bonded to the building material board and is not exposed on the surface. On the other hand, when the resin sheet according to the embodiment of the present invention is used, for example, as a reflective sheet for a plant factory, it is desirable that both sides have antibacterial properties and other functions, and therefore it is preferable to have a third functional layer.

[0064] The configuration of the third functional layer is preferably the same as that of the first functional layer, including preferred embodiments.

[0065] <Fourth functional layer> The resin sheet according to the embodiment of the present invention may have a fourth functional layer on the surface of the third functional layer. Preferably, the fourth functional layer is the same as the second functional layer described above. When the resin sheet according to the embodiment of the present invention is used in a building material laminate described later, the presence of a fourth functional layer makes it easier to obtain adhesion to the building material board. When a resin sheet according to an embodiment of the present invention is used, for example, as a reflective sheet for a plant factory, having a fourth functional layer makes it easier to obtain antistatic properties and printability, similar to the second functional layer.

[0066] The configuration of the fourth functional layer is preferably the same as that of the second functional layer, including preferred embodiments.

[0067] <Method for manufacturing resin sheets> <Method for manufacturing the base material, first functional layer, and third functional layer> The base material in the resin sheet according to the embodiment of the present invention can be obtained by mixing the materials constituting the base material with other components as needed, and then molding. The first functional layer can be obtained by mixing a thermoplastic resin, a functional agent, and other components as needed, and then molding. The third functional layer can be obtained in the same manner as the first functional layer. The molding method is not particularly limited, and various known molding methods can be used individually or in combination to produce the product. For example, it can be molded into a film using casting, calendering, rolling, inflation molding, etc., in which molten resin is extruded into a sheet using single-layer or multi-layer T-dies, I-dies, etc., connected to a screw-type extruder. A mixture of thermoplastic resin and an organic solvent or oil may be cast-molded or calendered, and then the solvent or oil may be removed to form a base material, a first functional layer, or a third functional layer.

[0068] The base material, the first functional layer, and the third functional layer may be molded separately and then laminated, or the base material and the first functional layer, or the first functional layer, the base material, and the third functional layer may be molded together. For example, by using a molding method such as co-extrusion, a laminate can be obtained in which the base material and the first functional layer or the third functional layer are laminated together.

[0069] When laminating a substrate with a first functional layer and a third functional layer together, molding methods include, for example, a multi-layer die system using a feed block or multi-manifold, and an extrusion lamination system using multiple dies. These methods can also be combined.

[0070] The base material, the first functional layer, and the third functional layer may each be an unstretched film or a stretched film. Examples of stretching methods include longitudinal stretching using the difference in peripheral speed of a group of rolls, transverse stretching using a tenter oven, sequential biaxial stretching combining these methods, rolling, simultaneous biaxial stretching using a combination of a tenter oven and a pantograph, and simultaneous biaxial stretching using a combination of a tenter oven and a linear motor. In addition, simultaneous biaxial stretching (inflation molding), in which molten resin is extruded into a tube shape using a circular die connected to a screw-type extruder and then air is blown into it, can also be used.

[0071] From the viewpoint of giving the resin sheet appropriate stiffness and adjusting the water vapor transmission coefficient as a porous material, it is preferable that at least one of the base material and the first functional layer is stretched. Furthermore, if the substrate has a multilayer structure, it is preferable that at least one of the layers is stretched. When stretching multiple layers, each layer may be stretched individually before stacking, or they may be stretched together after stacking. Alternatively, stretched layers may be stretched again after stacking.

[0072] When stretching is performed, the stretching temperature is preferably in a range above the glass transition temperature of the thermoplastic resin if the thermoplastic resin is amorphous. If the thermoplastic resin is crystalline, the stretching temperature is preferably in a range above the glass transition temperature of the amorphous portion of the thermoplastic resin and below the melting point of the crystalline portion of the thermoplastic resin, specifically a temperature 2 to 60°C lower than the melting point of the thermoplastic resin.

[0073] While there are no particular limitations on the stretching speed during the stretching process, it is preferable that it be within the range of 20 to 350 m / min from the viewpoint of stable stretch molding.

[0074] The stretching ratio when stretching can be appropriately determined considering the characteristics of the thermoplastic resin used. For example, when stretching a thermoplastic resin film containing a propylene homopolymer or copolymer thereof in one direction, the stretching ratio is usually about 1.2 times or more, preferably 2 times or more, while it is usually 12 times or less, preferably 10 times or less. On the other hand, when biaxial stretching is performed, the stretching ratio is usually 1.5 times or more, preferably 10 times or more, while it is usually 60 times or less, preferably 50 times or less, in terms of area stretching ratio.

[0075] Furthermore, when a thermoplastic resin film containing polyester resin is stretched in one direction, the stretching ratio is usually 1.2 times or more, preferably 2 times or more, usually 10 times or less, and preferably 5 times or less. When biaxially stretched, the stretching ratio is the area stretching ratio, and is usually 1.5 times or more, preferably 4 times or more, usually 20 times or less, and preferably 12 times or less. For example, if the substrate contains fillers, and the stretching ratio during stretching is within the above range, the desired porosity can be obtained and opacity is likely to improve. In addition, the substrate is less likely to break, and stable stretch molding tends to be possible.

[0076] As described above, a resin laminate of a first functional layer / substrate, or a resin laminate of a first functional layer / substrate / third functional layer can be obtained.

[0077] <Surface treatment> It is preferable that the first functional layer and / or the third functional layer is subjected to surface treatment. By subjecting the first functional layer and / or the third functional layer to surface treatment such as corona treatment, the surface free energy tends to be within a desired range. By activating the surfaces of the first functional layer and / or the third functional layer, the adhesion to the second functional layer and / or the fourth functional layer can be enhanced.

[0078] Examples of the surface treatment include corona discharge treatment, flame treatment, plasma treatment, glow discharge treatment, ozone treatment, etc., and these treatments can be combined. Among them, corona discharge treatment or flame treatment is preferable, and corona treatment is more preferable.

[0079] When performing corona discharge treatment, the discharge amount is preferably 600 J / m 2 (10 W·min / m 2 ) or more, and more preferably 1,200 J / m 2 (20 W·min / m 2 ) or more. Also, the said discharge amount is preferably 12,000 J / m 2 (200 W·min / m 2 ) or less, and more preferably 10,800 J / m 2 (180 W·min / m 2 ) or less. When performing flame treatment, the discharge amount is preferably 8,000 J / m 2 or more, and more preferably 20,000 J / m 2 or more. Also, the said discharge amount is preferably 200,000 J / m 2 or less, and more preferably 100,000 J / m 2 or less.

[0080] <Manufacture of the second functional layer and the fourth functional layer> The second functional layer can be formed by applying an aqueous solution containing a cationic water-soluble polymer and an aqueous solvent, and optionally containing a silane coupling agent, an antistatic agent, etc. (hereinafter also referred to as the "coating solution for forming the second functional layer") to the surface of the first functional layer, and then drying it. Similarly, the fourth functional layer can be formed by applying an aqueous solution containing a cationic water-soluble polymer and an aqueous solvent, and optionally containing a silane coupling agent, an antistatic agent, etc. (hereinafter also referred to as the "coating solution for forming the fourth functional layer") to the surface of the third functional layer, and then drying it.

[0081] The aqueous solvent may be water, or it may contain water as the main component along with water-soluble organic solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol, acetone, methyl ethyl ketone, ethyl acetate, toluene, and xylene. "Water as the main component" means that 50% or more of the total is water. Using an aqueous solvent facilitates process control and is preferable from a safety standpoint.

[0082] The amount of cationic water-soluble polymer contained in the coating liquid for forming the second functional layer or the coating liquid for forming the fourth functional layer (hereinafter collectively referred to as "coating liquid") is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 75% by mass or more, preferably 100% by mass or less, more preferably 95% by mass or less, even more preferably 90% by mass or less, and particularly preferably 80% by mass or less, based on the mass of all components of the coating liquid other than the aqueous medium.

[0083] When a silane coupling agent is used, the content of the silane coupling agent is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 20 parts by mass or more, based on 100 parts by mass of the cationic polymer in the coating solution. Furthermore, the content of the silane coupling agent in the coating solution is preferably 100 parts by mass or less, more preferably 50 parts by mass or less, and even more preferably 30 parts by mass or less, based on 100 parts by mass of the cationic polymer in the coating solution. Furthermore, the content of the silane coupling agent is preferably 0.1% by mass or more, more preferably 1% by mass or more, and even more preferably 3% by mass or more, based on the mass of all components of the coating solution other than the aqueous medium. Furthermore, the content of the silane coupling agent in the coating solution is preferably 20% by mass or less, more preferably 18% by mass or less, and even more preferably 15% by mass or less, based on the mass of all components of the coating solution other than the aqueous medium.

[0084] When an antistatic agent is used, the amount of antistatic agent contained in the coating solution is preferably 80% by mass or less, more preferably 60% by mass or less, even more preferably 40% by mass or less, and particularly preferably 30% by mass or less, based on the mass of all components of the coating solution other than the aqueous medium.

[0085] The coating solution may contain other auxiliary components as needed, such as crosslinking accelerators, antiblocking agents, pH adjusters, and defoamers.

[0086] The coating liquid can be applied using coating equipment such as a die coater, bar coater, roll coater, lip coater, gravure coater, spray coater, blade coater, reverse coater, or air knife coater. The amount of coating solution applied can be adjusted as appropriate, taking into consideration the thickness of the second or fourth functional layer after drying, the concentration of the components it contains, and other factors. The application of the coating solution and the drying of the coating film may be carried out in line with the molding of the laminated resin film, or off-line.

[0087] Drying of the coating film can be performed using drying equipment such as a hot air blower or an infrared dryer. When the coating solution contains a silane coupling agent, it is presumed that drying the coating film promotes a dehydration condensation reaction by the silane coupling agent in the coating film, generating a resin, which is a reaction product of the silane coupling agent and a cationic water-soluble polymer.

[0088] As described above, a resin sheet according to an embodiment of the present invention having a second functional layer / first functional layer / substrate configuration, or a resin sheet according to an embodiment of the present invention having a second functional layer / first functional layer / substrate / third functional layer / fourth functional layer configuration can be obtained.

[0089] <Surface resistivity of resin sheet> In the resin sheet according to an embodiment of the present invention, the surface resistivity of the second functional layer is preferably 1 × 10 -1 ~9×10 12 The resistivity is Ω / sq. This prevents problems such as blocking between sheets when storing the resin sheets in roll form or stacked. The surface resistivity of the second functional layer is more preferably 1 × 10⁻⁶. 11 Ω / sq. or less, more preferably 1 × 10⁻⁶ 10 It is less than or equal to Ω / sq. To achieve a desired surface resistivity, for example, the second functional layer may contain an antistatic agent. Furthermore, if the resin sheet has a fourth functional layer, it is preferable that the surface resistivity of the fourth functional layer is also within the above range. The surface resistivity of the resin sheet can be measured in accordance with JIS K6911:1995.

[0090] <Surface free energy of resin sheet> In the resin sheet according to the embodiment of the present invention, the surface free energy on the second functional layer side is preferably 34 to 80 mN / m. A high surface free energy increases the affinity for water (wettability), improves the expression of the functional agent, and makes it easier to obtain effects such as antibacterial properties. Furthermore, if the surface free energy on the second functional layer side is within the above range, the second functional layer is more easily formed stably. In addition, when a printed layer is further provided on the surface of the second functional layer, the adhesion with the printed layer is improved. Furthermore, the second functional layer is more easily formed stably. To bring the surface free energy within a desired range, one example of this is to apply a surface treatment such as corona treatment to the first functional layer. Furthermore, if the resin sheet has a fourth functional layer, it is preferable that the surface free energy of the fourth functional layer is also within the above range. The surface free energy of a resin sheet can be measured in accordance with JIS K6768:1999.

[0091] <Water vapor permeability coefficient of resin sheets> The resin sheet according to the embodiment of the present invention preferably has a water vapor transmission coefficient of 0.01 to 2.5 g / mm / (m²). 2 (24hr), more preferably 0.05~2.4 g / mm / (m 2 (24hr), and more preferably 0.1~2.3 g / mm / (m 2 (24hr), and particularly preferably 0.5~2.2 g / mm / (m 2 (24hr). Because the water vapor transmission coefficient is within the above range, for example, when the resin sheet is used in the building material laminate described later, it blocks the outflow of indoor air to the outside in winter and the inflow of warm, humid outside air into the room in summer, making it easier to maintain a comfortable indoor space without the use of special energy sources such as air conditioners. To achieve a desired water vapor transmission coefficient, methods such as using a resin sheet molded from thermoplastic resin instead of fibers, or controlling the porosity of the resin sheet, can be employed. The water vapor transmission coefficient of a resin sheet is determined, for example, by the cup method in accordance with JIS-Z-0208:1976, under conditions of 40°C and 90% relative humidity (g / m²).2 It can be calculated by measuring (24hr) and converting it from the thickness (mm) of the resin sheet.

[0092] <Applications of resin sheets> The resin sheet according to the embodiment of the present invention can fully exhibit functions such as antibacterial properties and also has excellent secondary processing properties, making it useful as a component of building material laminates, a reflective sheet for plant factories, and the like.

[0093] <Laminated building materials> Figure 3 shows a cross-sectional view of a building material laminate according to an embodiment of the present invention. The building material laminate 2 in Figure 3 comprises a building material board 20 and a resin sheet 1 according to an embodiment of the present invention provided on one main surface of the building material board 20. As shown in Figure 3, the second functional layer 12 is installed so that it is the outermost surface. Although not shown, the resin sheet 1 may also be provided on the other main surface of the building material board 20, but in that case as well, the second functional layer is installed so that it is the outermost surface.

[0094] Building boards include non-combustible and wood-based building boards. Non-combustible building boards include fiber-reinforced cement boards and metal sheets. Fiber-reinforced cement boards include gypsum board, slag gypsum board, calcium silicate board, and flexible board. Metal sheets include galvalume steel sheets and aluminum spandrels. Wood-based building boards include plywood. The thickness of the building material board is preferably about 3 to 20 mm.

[0095] The building material laminate can be manufactured by bonding a resin sheet according to an embodiment of the present invention to at least one surface of a building material board, for example, via an adhesive. The adhesive can be a protein-based adhesive, a hydrated carbon-based adhesive, a synthetic resin-based adhesive, a solvent-based adhesive, or the like.

[0096] In a building material laminate, it is preferable that the second functional layer of the resin sheet be located on the outermost surface, from the viewpoint of exhibiting functions such as antibacterial properties and secondary processing properties such as printability. The building material laminate can be used as an interior material for walls and can be used to form a wall in combination with insulation materials and exterior materials.

[0097] Furthermore, the resin sheet according to the embodiment of the present invention can be used as is for reflective sheets for plant factories. Various types of printing may be applied to at least one surface of such reflective sheets for plant factories, and to the surface of the main surface side of the building material laminate (the side opposite to where the building material board is provided). Various known printing methods include offset printing, gravure printing, flexographic printing, letterpress printing, screen printing, inkjet recording, thermal recording, thermal transfer recording, and electrophotographic recording.

[0098] Based on the above, this specification discloses the following resin sheets and building material laminates. [1] A resin sheet comprising a base material, a first functional layer provided on one main surface of the base material and containing a thermoplastic resin and a functional agent, and a second functional layer provided on the surface of the first functional layer and containing a cationic water-soluble polymer, The functional agent comprises at least one of calcium hydroxide and a metal support. A resin sheet having a thickness of 0.1 μm or less for the second functional layer. [2] The resin sheet according to [1], wherein the content of the cationic water-soluble polymer in the second functional layer is 30 to 100% by mass. [3] The resin sheet according to [1] or [2], wherein the cationic water-soluble polymer contains a quaternary ammonium salt. [4] The surface resistivity of the second functional layer is 1 × 10 -1 ~9×10 12 A resin sheet as described in any of [1] to [3], with a density of Ω / sq. [5] The resin sheet according to any one of [1] to [4], wherein the surface free energy on the second functional layer side is 34 to 80 mN / m. [6] The resin sheet according to any one of [1] to [5], wherein the first functional layer contains 1 to 30% by mass of the functional agent. [7] The resin sheet according to any one of [1] to [6], wherein the first functional layer is a stretched porous layer. [8] Water vapor transmission coefficient of 0.01 to 2.5 g / mm / (m 2 A resin sheet as described in any of [1] to [7], which is 24 hours long. A building material laminate comprising a resin sheet as described in any of [9], [1] to [8], and a building material board, wherein the second functional layer of the resin sheet is located on the outermost surface. [Examples]

[0099] The present invention will be described in more detail below with reference to examples and comparative examples. The materials, amounts used, proportions, processing content, and processing procedures shown in the examples can be modified as appropriate without departing from the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the specific examples shown below.

[0100] The materials used are listed below. Propylene homopolymer (manufactured by Nippon Polypropylene Co., Ltd., product name: Novatec PP FY4, MFR (230℃, 2.16kg load): 5g / 10min, melting point: 165℃) Heavy calcium carbonate (manufactured by Bihoku Powdering Industry Co., Ltd., product name: Softon 1800, average particle size: 1.2 μm) Functional agent: Metal carrier (manufactured by Ishizuka Glass Co., Ltd., product name: Ion Pure ZAF HS, average particle size: 1.0 μm) Functional ingredient: Calcined scallop shell powder (manufactured by Nikken Chemical Research Institute Co., Ltd., product name: Shell Nature, average particle size: 3.0 μm, contains 35% calcium hydroxide by mass) Cationic water-soluble polymer: Polyethyleneimine polymer containing primary to tertiary amino groups (manufactured by Mitsubishi Chemical Corporation, product name: Saftomer AC-72) Antistatic agent: Polymer-type antistatic agent (Product name: Saftomer ST-3200 (manufactured by Mitsubishi Chemical Corporation), solid content concentration: 25% by mass, quaternary ammonium salt) Silane coupling agent: 3-Glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KBM-403) Non-cationic water-soluble polymer (acrylic acid polymer): Sodium polyacrylate (product name: Aqualic L DL-453 (manufactured by Nippon Shokubai Co., Ltd.), solid content concentration: 35% by mass)

[0101] <Preparation of resin compositions for the base material, first functional layer, and third functional layer> Resin compositions a to h were prepared by mixing each of the materials shown in Table 1 in the proportions shown in Table 1.

[0102] [Table 1]

[0103] <Preparation Examples 1-6: Preparation of coating solutions for the second or fourth functional layer> Aqueous solutions containing the types and quantities of materials shown in Table 2 (polymers are calculated on a solids basis) were prepared as coating solutions.

[0104] [Table 2]

[0105] <Example 1> Resin composition b was melt-kneaded in an extruder set to 230°C, then supplied to an extrusion die set to 250°C and extruded into a sheet. This sheet was then cooled to 60°C using a cooling device to obtain an unstretched sheet. This unstretched sheet was heated to 135°C and stretched five times in the longitudinal direction using the difference in peripheral speed of the roll group. Next, resin composition c was melt-kneaded in an extruder set to 250°C, then extruded into a sheet and laminated onto the first surface of the resin layer made of resin composition b. Next, the resin composition g was melt-kneaded in an extruder set to 250°C, then extruded into a sheet and laminated onto the second surface of the resin layer made of the previously formed resin composition b. In this way, a laminated sheet was obtained in which three layers were laminated: a resin layer made of resin composition g, a resin layer made of resin composition b, and a resin layer made of resin composition c. Next, the three-layer laminated sheet was cooled to 60°C, then heated to approximately 150°C using a tenter oven and stretched 8.5 times in the transverse direction, after which it was further heated to 160°C for heat treatment. Next, the material was cooled to 60°C, and the edges were slit to obtain a resin sheet with a total thickness of 80 μm. In the resin sheet, each layer, consisting of the resin composition (g / b / c), corresponds to the third functional layer, the base layer, and the first functional layer, respectively, and has a thickness (10 μm / 60 μm / 10 μm) and number of stretch axes (1 axis / 2 axes / 1 axis). The porosity of the base material was measured to be 35%. 30W·min / m² applied to both sides of the resin sheet 2 After corona discharge treatment under the specified conditions, the coating solution prepared in Preparation Example 1 was applied to each surface using a roll coater to achieve a dry thickness of 0.05 μm. The coating film was dried in a 60°C oven to form the second and fourth functional layers, obtaining a resin sheet.

[0106] <Examples 2-10, Comparative Examples 1-6> A resin sheet was obtained in the same manner as in Example 1, except that the conditions such as the type of resin composition, the thickness of each layer, the stretching conditions, and the type of coating liquid were changed to those shown in Table 3.

[0107] [Table 3]

[0108] <Antibacterial Test> Antimicrobial testing was performed on the second functional layer surface of the resin sheets obtained in the examples and comparative examples, in accordance with JIS Z2801, using Staphylococcus aureus and Escherichia coli as test strains. The antimicrobial activity values ​​obtained for both test strains were used to evaluate the antimicrobial activity according to the following criteria. ○: Antibacterial activity value of 3.0 or higher △: Antibacterial activity value is 2.0 or higher but less than 3.0 ×: Antibacterial activity value is less than 2.0 (○ or △ means passing)

[0109] <Mold resistance test> A mold resistance test was conducted on the second functional layer side surface of the resin sheets obtained in the examples and comparative examples, in accordance with JIS Z2911 (Test Methods for Plastic Products B), using Aspergillus niger, Penicillium pinophilum, paecilomyces variotii, Trichoderma virens, and Cheatomium globosum as test molds. For each test mold, the mold growth state after 4 weeks was compared with that of biaxially oriented polypropylene film (FOS-AQ non-corona treated surface, manufactured by Futamura Chemical Co., Ltd.), and the mold resistance was evaluated according to the following criteria. ○: No mycelial growth observed. △: Mycelial growth is limited to within 1 / 3 of the test specimen area. ×: Mycelial growth exceeds 1 / 3 of the test specimen area. (○ or △ means passing)

[0110] <Antiviral Test> Antiviral tests were conducted on the second functional layer surface of the resin sheets obtained in the examples and comparative examples, in accordance with ISO 21702, using Influenza A virus (H3N2): ATCC VR 167 as the virus. The antibacterial activity was evaluated using the obtained antiviral activity values ​​according to the following criteria. ○: Antiviral activity value of 3.0 or higher △: Antiviral activity value is 2.0 or higher but less than 3.0 ×: Antiviral activity value less than 2.0 (○ or △ means passing)

[0111] <Printability Test> Using a color laser printer (manufactured by Casio Corporation, product name: N4-612II), test images were recorded on the second functional layer of the resin sheets obtained in the examples and comparative examples using four-color toners: yellow, cyan, magenta, and black. Subsequently, the resin sheets on which the test images were recorded were immersed in water (ion-exchanged water) filling a tray so as not to float, and the recorded images were rubbed vigorously with a coin and visually evaluated according to the following evaluation criteria. ○: No change in recorded image. △: Some areas of the recorded image may be peeling due to scratches. ×: Peeling occurs across the entire surface of the scratched area in the recorded image. (○ or △ means passing)

[0112] <Adhesion Test> Glassine paper (G7B, manufactured by Oji Tack Co., Ltd.) treated with silicone was prepared as a release liner. A mixture of a solvent-based acrylic adhesive (Olivine BPS1109, manufactured by Toyo Chem Co., Ltd.), an isocyanate-based crosslinking agent (Olivine BHS8515, manufactured by Toyo Chem Co., Ltd.), and toluene in a ratio of 100:3:45 was applied to the silicone-treated surface of the glassine paper. The resulting mixture had a basis weight of 25 g / m² after drying. 2 The surface was coated with a comma coater and dried to form an adhesive layer. Next, the resin sheets obtained in the examples and comparative examples were laminated so that the adhesive layer and the fourth functional layer were in contact, and then pressed and bonded with a pressure roll to form an adhesive layer on the resin sheet. The release sheet of the adhesive label was peeled off and attached to a gypsum board (manufactured by Yoshino Gypsum Co., Ltd., product name "Tiger Board"), and this was stored at room temperature for one week. Adhesive tape (manufactured by Nichiban Co., Ltd., product name "Cellotape (registered trademark)", brand name "CT-18") was applied along the entire length of one of the four sides of the resin sheet to make it easy to hold by hand. While maintaining an angle of approximately 135° between the surface of the gypsum board and the peeled portion of the resin sheet, the resin sheet was peeled off the gypsum board by pulling on the peeled portion. The peel propagation state and peeling force of the resin sheet at this time were evaluated according to the following criteria. ○: Has strong peeling power and peels off completely cleanly. △: The peeling power is slightly weak, but it peels off cleanly across the entire surface. ×: Weak peeling force (○ or △ means passing)

[0113] <Moisture resistance test> The water vapor transmission coefficient of the resin sheets obtained in the examples and comparative examples was measured, and the moisture resistance was evaluated according to the following criteria. ○: 5.0g·mm / (m 2 ·24hr) or less △: 5.0g·mm / (m 2 ·24hr)Ultra 10.0g·mm / (m 2 ·24hr) or less ×: 10.0g·mm / (m 2 ·24hr) super (○ or △ means passing)

[0114] The results of each of the above tests are shown in Table 4 below.

[0115] [Table 4]

[0116] Based on the results above, the resin sheets of Examples 1 to 10 met the acceptance criteria in all functional tests, including antibacterial, antifungal, and antiviral properties, as well as secondary processing tests, including adhesion and printability. A comparison between Example 1 and Example 2, and between Examples 3 to 6, shows that increasing the functional agent content improved functions such as antibacterial, antifungal, and antiviral properties. In Examples 9 and 10, the use of a coating solution without a silane coupling agent during the formation of the second functional layer resulted in a slight decrease in functional properties such as antibacterial properties and secondary processing properties such as adhesion, but the acceptance criteria were still met. The resin sheets of Comparative Examples 1 and 2 did not exhibit antibacterial, antifungal, and antiviral functions because the first functional layer did not contain a functional agent. The resin sheet of Comparative Example 3 lacked a second functional layer, and therefore did not exhibit secondary processing properties such as adhesion, printability, and moisture resistance. In Comparative Example 4, the resin sheet was not subjected to corona discharge treatment, so the second functional layer was not formed in a layered manner. As a result, its secondary processability was insufficient. In Comparative Example 5, the functional agent was not present in the first functional layer of the resin sheet, but rather on the surface of the resin sheet. As a result, it absorbed moisture, reducing the cohesive strength of the coating film, and consequently, it failed to exhibit adhesiveness and printability. In Comparative Example 6, the resin sheet did not contain a cationic water-soluble polymer in its second functional layer, and therefore the functional agent's effect was not fully realized. [Industrial applicability]

[0117] The resin sheet according to the embodiment of the present invention retains antibacterial properties and other functions, is also suitable for secondary processing, and is useful for household goods, building materials, agricultural products, and the like. [Explanation of symbols]

[0118] 1. Resin sheet 10...Base material 11...First functional layer 12...Second functional layer 13...Third functional layer 14...Fourth functional layer 2. Laminated building materials 20... Building material boards

Claims

1. A resin sheet comprising a base material, a first functional layer provided on one main surface of the base material and containing a thermoplastic resin and a functional agent, and a second functional layer provided on the surface of the first functional layer and containing a cationic water-soluble polymer, The functional agent comprises at least one of calcium hydroxide and a metal support. A resin sheet having a thickness of 0.1 μm or less for the second functional layer.

2. The resin sheet according to claim 1, wherein the content of the cationic water-soluble polymer in the second functional layer is 30 to 100% by mass.

3. The resin sheet according to claim 1 or 2, wherein the cationic water-soluble polymer contains a quaternary ammonium salt.

4. The surface resistivity of the second functional layer is 1 × 10 －１ ~9 x 10 １２ A resin sheet according to claim 1 or 2, wherein the density is Ω / sq.

5. The resin sheet according to claim 1 or 2, wherein the surface free energy on the second functional layer side is 34 to 80 mN / m.

6. The resin sheet according to claim 1 or 2, wherein the first functional layer contains 1 to 30% by mass of the functional agent.

7. The resin sheet according to claim 1 or 2, wherein the first functional layer is a stretched porous layer.

8. Water vapor transmission coefficient of 0.01 to 2.5 g / mm / (m ２ The resin sheet according to claim 1 or 2, wherein the resin is 24hr.

9. A building material laminate comprising a resin sheet according to claim 1 or 2 and a building material board, wherein the second functional layer of the resin sheet is located on the outermost surface.

Images