Self-adsorption laminate and method for manufacturing the same

Abstract

To provide a self-adsorption laminate which is excellent in deodorizing properties and can be efficiently manufactured.SOLUTION: The self-adsorption laminate includes a substrate and a self-adsorption foam sheet. The self-adsorption foam sheet contains a polymer and metal-containing oxidized cellulose nanofibers containing a metal other than sodium in the form of a salt. The substrate has an air permeability of more than 0 cm3 / cm2 / s and a basis weight of 40 g / m2 or more. The polymer preferably contains an acrylate monomer unit and / or a methacrylate monomer unit.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a self-adhesive laminate and a method for producing the self-adhesive laminate.

Background Art

[0002] Conventionally, as an adhesive sheet used by being attached to a smooth adherend such as window glass, a sheet-like member made of a foaming material having a large number of fine pores and having self-adhesive properties, that is, a self-adhesive foaming sheet (hereinafter, may be simply referred to as "foaming sheet") is used. The adhesion mode of the self-adhesive foaming sheet is not adhesive bonding with glue, but adsorption to the adherend using fine pores. Therefore, the self-adhesive foaming sheet is easier to reattach than a conventional adhesive sheet using glue, and is suitably used for applications such as wallpaper, posters, and stickers. When used for these applications, the self-adhesive foaming sheet is usually used in the form of a self-adhesive laminate (hereinafter, may be simply referred to as "laminate sheet") laminated with a base material. This self-adhesive laminate is produced, for example, by forming a foaming composition obtained by foaming a composition for a self-adhesive foaming sheet containing a polymer into a sheet shape on a base material. And the self-adhesive laminate can be advantageously used for the above-mentioned applications by applying decoration such as printing to the surface on the base material side.

[0003] By the way, in recent years, regarding resin foams, adding modified cellulose nanofibers has been studied for the purpose of imparting adsorption performance and strength for odor gases and the like. For example, Patent Document 1 describes that by foaming a composition for a foam resin containing cellulose nanofibers having a sodium salt type or acid type carboxy group introduced on its surface and a resin emulsion, a foam excellent in strength and capable of adsorbing odors such as ammonia can be obtained.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] However, according to the study by the present inventor, a conventional self-adhesive laminate using a self-adhesive foamed sheet containing modified cellulose nanofibers having a carboxy group in sodium salt form or acid form on its surface has insufficient deodorizing properties.

[0006] In view of such problems, the present inventor has improved the deodorizing properties of the self-adhesive foamed sheet itself by using metal-containing oxidized cellulose nanofibers containing a metal other than sodium in the form of a salt as the cellulose nanofibers, and has newly conceived to improve the deodorizing properties of the self-adhesive laminate by making it easier for a gas containing an odor substance to come into contact with the self-adhesive foamed sheet by using a base material having air permeability as the base material.

[0007] However, when a base material having air permeability is used, when producing a self-adhesive laminate by forming a foamed composition obtained by foaming a composition for a self-adhesive foamed sheet into a sheet shape on the base material, the foamed composition may permeate the base material, soiling the production equipment or reducing the yield.

[0008] Therefore, an object of the present invention is to provide a self-adhesive laminate having excellent deodorizing properties and capable of being efficiently produced.

MEANS FOR SOLVING THE PROBLEMS

[0009] The present inventor conducted intensive studies for the purpose of solving the above problems. As a result, the present inventor newly found that the deodorizing properties of the self-adhesive laminate can be improved by including metal-containing oxidized cellulose nanofibers containing a metal other than sodium in the form of a salt in the self-adhesive foamed sheet and using a base material having air permeability, and that the self-adhesive laminate can be efficiently produced if the basis weight of the base material having air permeability is set to a predetermined value or more, thus completing the present invention.

[0010] That is, the object of the present invention is to advantageously solve the above problems. The self-adhesive laminate of the present invention includes a base material and a self-adhesive foam sheet. The self-adhesive foam sheet includes a polymer and a metal-containing oxidized cellulose nanofiber containing a metal other than sodium in the form of a salt. The base material has an air permeability of more than 0 cm 3 / cm 2 / second and a basis weight of 40 g / m 2 or more. Thus, by incorporating a metal-containing oxidized cellulose nanofiber containing a metal other than sodium in the form of a salt into the self-adhesive foam sheet and using a base material having air permeability, a self-adhesive laminate excellent in deodorizing properties can be obtained. Further, if the basis weight of the base material is 40 g / m 2 or more, permeation of the material used for forming the self-adhesive foam sheet through the base material can be suppressed, and the self-adhesive laminate can be efficiently manufactured. In the present invention, the "air permeability" and "basis weight" of the base material can be measured by the methods described in the examples.

[0011] Here, in the self-adhesive laminate of the present invention, it is preferable that the polymer contains a (meth)acrylate monomer unit. A polymer containing a (meth)acrylate monomer unit is excellent in flexibility and can impart good adsorptivity to the foam sheet. In the present invention, the fact that the polymer "contains a monomer unit" means that "the repeating unit derived from the monomer is contained in the polymer obtained using the monomer". Further, in the present invention, "(meth)acrylate" means acrylate and / or methacrylate.

[0012] Also, in the self-adhesive laminate of the present invention, it is preferable that the number average fiber diameter of the metal-containing oxidized cellulose nanofiber is 100 nm or less. The metal-containing oxidized cellulose nanofiber having a number average fiber diameter of 100 nm or less is excellent in dispersibility, and even if the blending amount is small, it can impart good deodorizing properties to the foam sheet. In the present invention, the "number average fiber diameter" of the metal-containing oxidized cellulose nanofiber can be determined by measuring the fiber diameters of five or more metal-containing oxidized cellulose nanofibers using an atomic force microscope and calculating the arithmetic mean of the measured fiber diameters.

[0013] Furthermore, in the self-adhesive laminate of the present invention, it is preferable that the metal-containing oxidized cellulose nanofiber is a metal-containing carboxylated cellulose nanofiber. The metal-containing carboxylated cellulose nanofiber has excellent dispersibility, and even when the blending amount is small, it can impart good deodorizing properties to the foamed sheet.

[0014] Also, in the self-adhesive laminate of the present invention, it is preferable that the metal other than sodium is at least one selected from the group consisting of silver, zinc, and copper. The metal-containing oxidized cellulose nanofiber containing at least one selected from the group consisting of silver, zinc, and copper has excellent deodorizing properties and can impart good deodorizing properties to the foamed sheet.

[0015] And, in the self-adhesive laminate of the present invention, it is preferable that the base material contains PET fibers. By using a base material containing PET (polyethylene terephthalate) fibers, the deodorizing property, strength, and heat resistance of the self-adhesive laminate can be made to coexist at a high level.

[0016] Also, this invention aims to advantageously solve the above problems. The manufacturing method of the self-adhesive laminate of the present invention includes a step of foaming a composition for a self-adhesive foamed sheet containing a polymer and a metal-containing oxidized cellulose nanofiber containing a metal other than sodium in the form of a salt to obtain a foamed composition, and a step of forming the foamed composition into a sheet shape on a base material. The base material has an air permeability of more than 0 cm 3 / cm 2 / second, and a basis weight of 40 g / m 2It is characterized by the above. Thus, by incorporating a metal-containing oxidized cellulose nanofiber containing a metal other than sodium in the form of a salt into the composition for the self-adhesive foam sheet and using a breathable substrate, a self-adhesive laminate excellent in deodorizing properties can be obtained. Further, if the basis weight of the substrate is 40 g / m 2 or more, when the foaming composition is formed into a sheet on the substrate, permeation of the foaming composition through the substrate can be suppressed, and the self-adhesive laminate can be efficiently manufactured.

Effects of the Invention

[0017] According to the present invention, it is possible to provide a self-adhesive laminate excellent in deodorizing properties and capable of being efficiently manufactured.

Modes for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present invention will be described in detail. Here, the self-adhesive laminate of the present invention is used by being attached to an adherend indoors or outdoors, and can be manufactured, for example, using the manufacturing method of the self-adhesive laminate of the present invention.

[0019] (Self-adhesive laminate) The self-adhesive laminate of the present invention includes a foaming layer made of a self-adhesive foam sheet and a substrate as a support layer that supports the foaming layer. And, the self-adhesive laminate of the present invention requires that the foaming sheet contains a polymer and a metal-containing oxidized cellulose nanofiber containing a metal other than sodium in the form of a salt. Further, the self-adhesive laminate of the present invention requires that the substrate has an air permeability of more than 0 cm 3 / cm 2 / second and a basis weight of 40 g / m 2 or more. Note that the foaming sheet may be formed directly on the substrate or may be formed on the substrate via an arbitrary layer, but from the viewpoint of enhancing the deodorizing properties of the self-adhesive laminate, it is preferably formed directly on the substrate. Further, the self-adhesive laminate of the present invention may have foaming sheets on both sides of the substrate.

[0020] And since the foamed sheet of the self - adsorbing laminate of the present invention contains metal - containing oxidized cellulose nanofibers containing a metal other than sodium in the form of a salt, it is excellent in strength and can exhibit high deodorizing performance. Further, the self - adsorbing laminate of the present invention uses a base material with an air permeability of more than 0 cm 3 / cm 2 / sec, and since the gas containing odor substances easily permeates through the base material and contacts the foamed sheet, it can exhibit excellent deodorizing performance as compared with the case of using a base material having no air permeability. Furthermore, since the basis weight of the base material of the self - adsorbing laminate of the present invention is 40 g / m 2 or more, it can suppress the material used for forming the foamed sheet from permeating through the base material, prevent fouling of the manufacturing apparatus and reduction in yield, and efficiently manufacture the self - adsorbing laminate. Note that the odor deodorized by the self - adsorbing laminate of the present invention is not particularly limited, and examples include ammonia odor, methyl mercaptan odor, hydrogen sulfide odor, and the like.

[0021] <Self - adsorbing foamed sheet> The self - adsorbing foamed sheet has a large number of fine pores. Usually, the self - adsorbing laminate is bonded to the adherend by adsorbing the self - adsorbing foamed sheet to the adherend. And the self - adsorbing foamed sheet contains a polymer and metal - containing oxidized cellulose nanofibers containing a metal other than sodium in the form of a salt, and optionally further contains other additives.

[0022] [Polymer] The polymer forms a resin matrix in the foamed sheet.

[0023] And as the polymer, any polymer capable of forming a foamed sheet can be used. Specifically, the polymer is not particularly limited, but for example, it can contain at least one monomer unit selected from the group consisting of (meth) acrylate monomer units, unsaturated carboxylic acid monomer units, vinyl cyanide monomer units, and alkenyl aromatic monomer units. Among them, the polymer preferably contains (meth)acrylate monomer units. This is because flexibility is imparted to the foamed sheet, and the foamed sheet can exhibit good adsorption force (self - adhesion). In addition, the polymer may contain monomer units other than (meth)acrylate monomer units, unsaturated carboxylic acid monomer units, vinyl cyanide monomer units, and alkenyl aromatic monomer units (hereinafter referred to as "other monomer units"). Note that the polymer may be one in which a cross - linked structure is formed intramolecularly and / or intermolecularly using a cross - linking agent or cross - linkable monomer units.

[0024] (Meth)acrylate monomer units are repeating units derived from (meth)acrylate monomers. The (meth)acrylate monomer is not particularly limited. For example, (meth)acrylate alkyl ester monomers such as methyl (meth)acrylate, ethyl (meth)acrylate, n - propyl (meth)acrylate, n - butyl (meth)acrylate, sec - butyl (meth)acrylate, n - heptyl (meth)acrylate, n - hexyl (meth)acrylate, n - octyl (meth)acrylate, 2 - ethylhexyl (meth)acrylate, n - dodecyl (meth)acrylate; (meth)acrylate alkoxyalkyl ester monomers such as 2 - methoxyethyl (meth)acrylate, 3 - methoxypropyl (meth)acrylate, 3 - methoxybutyl (meth)acrylate, ethoxymethyl (meth)acrylate, etc. can be mentioned. Note that the (meth)acrylate monomer may be used alone or in combination of two or more. In the present invention, "(meth)acryl" means acrylic and / or methacrylic.

[0025] Here, as the (meth)acrylate monomer, from the viewpoint of further enhancing the flexibility of the foamed sheet and ensuring better adhesion of the laminated sheet, an alkyl (meth)acrylate monomer is preferred. An alkyl (meth)acrylate monomer in which the number of carbon atoms of the alkyl group bonded to the non-carbonyl oxygen atom is 1 or more and 14 or less (for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, sec-butyl acrylate, n-heptyl acrylate, n-hexyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, n-octyl methacrylate, n-dodecyl methacrylate, etc.) is more preferred. Among them, from the viewpoints of adhesion and cost, n-butyl acrylate, ethyl acrylate, and 2-ethylhexyl acrylate are preferred.

[0026] And the proportion of the (meth)acrylate monomer unit in the polymer is preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, particularly preferably 85% by mass or more, preferably 99% by mass or less, more preferably 95% by mass or less, and still more preferably 92% by mass or less, with respect to 100% by mass of all the repeating units (all monomer units) contained in the polymer. If the proportion of the (meth)acrylate monomer unit in the polymer is 60% by mass or more, sufficient adhesion of the foamed sheet can be ensured. On the other hand, if the proportion of the (meth)acrylate monomer unit in the polymer is 99% by mass or less, the adhesion of the foamed sheet will not increase excessively. Therefore, resin residue on the adherend of the self-adhesive laminate provided with the foamed sheet can be suppressed.

[0027] The unsaturated carboxylic acid monomer unit is a repeating unit derived from the unsaturated carboxylic acid monomer. Specific examples of the unsaturated carboxylic acid monomer include, for example, α,β-ethylenically unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid; α,β-ethylenically unsaturated polycarboxylic acids such as itaconic acid, maleic acid, and fumaric acid; partial esters of α,β-ethylenically unsaturated polycarboxylic acids such as monomethyl itaconate, monobutyl maleate, and monopropyl fumarate; and the like. In addition, those having a group that can be derived into a carboxylic acid group by hydrolysis, such as maleic anhydride and itaconic anhydride, can also be used in the same manner. Among these, itaconic acid, acrylic acid, and methacrylic acid are preferred, and acrylic acid is more preferred, from the viewpoints of reactivity with a crosslinking agent described later, stability of the polymer latex, and cost. Note that the unsaturated carboxylic acid monomer may be used alone or in combination of two or more.

[0028] And the proportion of the unsaturated carboxylic acid monomer unit in the polymer is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, preferably 10% by mass or less, more preferably 5% by mass or less, and still more preferably 2.5% by mass or less, with respect to 100% by mass of all the repeating units (all monomer units) contained in the polymer. When the proportion of the unsaturated carboxylic acid monomer unit in the polymer is 0.1% by mass or more, the crosslinking reaction by the crosslinking agent described later can proceed sufficiently. As a result, while imparting sufficient strength to the foamed sheet, it is possible to suppress the resin residue on the adherend of the self-adhesive laminate including the foamed sheet. On the other hand, when the proportion of the unsaturated carboxylic acid monomer unit in the polymer is 10% by mass or less, it becomes easy to keep the viscosity of the polymerization system during polymerization within an appropriate range, and there is no such problem that the crosslinking of the polymer proceeds excessively and the self-adhesive force of the foamed sheet is impaired.

[0029] The vinyl cyanide monomer unit is a repeating unit derived from a vinyl cyanide monomer. Specific examples of the vinyl cyanide monomer include α,β-ethylenically unsaturated nitrile monomers. The α,β-ethylenically unsaturated nitrile monomers are not particularly limited as long as they are α,β-ethylenically unsaturated compounds having a nitrile group. For example, acrylonitrile; α-halogenoacrylonitriles such as α-chloroacrylonitrile and α-bromoacrylonitrile; α-alkylacrylonitriles such as methacrylonitrile and α-ethylacrylonitrile; and the like can be mentioned. Among these, acrylonitrile is preferable from the viewpoint of increasing the breaking strength of the foamed sheet. Note that the vinyl cyanide monomer may be used alone or in combination of two or more.

[0030] The proportion of the vinyl cyanide monomer unit in the polymer is preferably 1% by mass or more, more preferably 3% by mass or more, still more preferably 5% by mass or more, preferably 30% by mass or less, more preferably 20% by mass or less, and still more preferably 15% by mass or less, with respect to 100% by mass of all the repeating units (all monomer units) contained in the polymer. When the proportion of the vinyl cyanide monomer unit in the polymer is 1% by mass or more, it is possible to suppress the resin residue on the adherend of the self-adhesive laminate provided with the foamed sheet while imparting sufficient strength to the foamed sheet. On the other hand, when the proportion of the vinyl cyanide monomer unit in the polymer is 30% by mass or less, it is possible to sufficiently ensure the flexibility of the foamed sheet and obtain a self-adhesive laminate having good self-adhesion.

[0031] The alkenyl aromatic monomer unit is a repeating unit derived from an alkenyl aromatic monomer. Specific examples of the alkenyl aromatic monomer include, for example, styrene, α-methylstyrene, α-chlorostyrene, vinyltoluene, divinylbenzene, and the like. Among these, styrene is preferable from the viewpoints of polymerizability and cost. Note that the alkenyl aromatic monomer may be used alone or in combination of two or more.

[0032] And the proportion of the alkenyl aromatic monomer unit in the polymer is preferably 0.5% by mass or more, more preferably 1% by mass or more, still more preferably 1.5% by mass or more, preferably 20% by mass or less, more preferably 10% by mass or less, and still more preferably 5% by mass or less, with respect to 100% by mass of all the repeating units (all monomer units) contained in the polymer. If the proportion of the alkenyl aromatic monomer unit in the polymer is 0.5% by mass or more, it is possible to prevent the intrusion of water into the foamed sheet based on the hydrophobicity of the alkenyl aromatic monomer unit, and the water resistance of the foamed sheet can be enhanced. On the other hand, if the proportion of the alkenyl aromatic monomer unit in the polymer is 20% by mass or less, the flexibility of the foamed sheet can be sufficiently ensured, and a self-adhesive laminate having good self-adhesion can be obtained.

[0033] The other monomer units are repeating units derived from other monomers copolymerizable with the monomers described above. Examples of the other monomers include conjugated diene monomers, α,β-ethylenically unsaturated polyvalent carboxylic acid complete ester monomers, carboxylic acid unsaturated alcohol ester monomers, olefinic monomers, crosslinkable monomers, and the like. These monomers may be used alone or in combination of two or more.

[0034] Specific examples of the conjugated diene monomer include, for example, butadiene, isoprene, 1,3-pentadiene, cyclopentadiene, and the like.

[0035] Specific examples of the α,β-ethylenically unsaturated polyvalent carboxylic acid complete ester monomer include dimethyl fumarate, diethyl fumarate, dimethyl maleate, diethyl maleate, dimethyl itaconate, and the like.

[0036] Specific examples of the carboxylic acid unsaturated alcohol ester monomer include vinyl acetate, and the like.

[0037] Specific examples of the olefin monomer include ethylene, propylene, butene, pentene, and the like.

[0038] The crosslinkable monomer is a monomer capable of efficiently crosslinking inside the polymer molecule and / or between polymer molecules. The crosslinkable monomer is not particularly limited as long as it can crosslink the polymer, and examples thereof include polyfunctional monomers having a plurality of polymerizable unsaturated bonds (excluding the above conjugated diene monomers) and monomers having a crosslinkable functional group.

[0039] When using a crosslinkable monomer, the proportion of the crosslinkable monomer unit in the polymer is preferably 0.1% by mass or more and 10% by mass or less, with the total repeating units (total monomer units) contained in the polymer being 100% by mass. If the proportion of the crosslinkable monomer unit in the polymer is within the above range, it becomes easy to keep the viscosity of the polymerization system during polymerization within an appropriate range, and it also becomes easy to prevent the crosslinking of the polymer from proceeding excessively and impairing the self-adsorbability of the foamed sheet.

[0040] Examples of the polyfunctional monomer include bifunctional monomers such as divinylbenzene, ethylene diacrylate, ethylene dimethacrylate, and allyl methacrylate; trifunctional monomers such as trimethylolpropane trimethacrylate; and the like. The polyfunctional monomer preferably has an unsaturated bond at the terminal. The polyfunctional monomer may be used alone or in combination of two or more.

[0041] Examples of the monomer having a crosslinkable functional group include monomers having functional groups such as organic acid groups other than carboxy groups, hydroxyl groups, amino groups, amide groups, mercapto groups, and epoxy groups.

[0042] The monomer having an organic acid group is not particularly limited, and typical examples thereof include monomers having an organic acid group such as a sulfonic acid group. In addition to these, monomers containing a sulfenic acid group, a sulfinic acid group, a phosphoric acid group, etc. can also be used.

[0043] Specific examples of the monomer having a sulfonic acid group include α,β-unsaturated sulfonic acids such as allyl sulfonic acid, methallyl sulfonic acid, vinyl sulfonic acid, and acrylamide-2-methylpropanesulfonic acid, and salts thereof.

[0044] When using the monomer having an organic acid group, the content of the monomer unit derived from the monomer having an organic acid group in the polymer is preferably 0.1% by mass or more and 10% by mass or less, and more preferably 0.5% by mass or more and 5% by mass or less. When the content of the monomer unit derived from the monomer having an organic acid group in the polymer is within the above range, it becomes easy to keep the viscosity of the polymerization system during polymerization within an appropriate range, and it also becomes easy to prevent the crosslinking of the polymer from proceeding excessively and impairing the self-adsorbability of the foamed sheet.

[0045] The monomer unit having an organic acid group is preferably introduced into the polymer by polymerization of the monomer having an organic acid group because it is simple, but an organic acid group may be introduced by a known polymer reaction after the polymer is formed.

[0046] When using a monomer having a functional group other than an organic acid group (hydroxyl group, amino group, amide group, epoxy group), the content of the monomer unit derived from the monomer having a functional group other than an organic acid group in the polymer is preferably 10% by mass or less. When the content of the monomer unit derived from the monomer having a functional group other than an organic acid group in the polymer is 10% by mass or less, it becomes easy to keep the viscosity of the polymerization system during polymerization within an appropriate range, and it also becomes easy to prevent the crosslinking of the polymer from proceeding excessively and impairing the self-adsorbability of the foamed sheet.

[0047] In addition, from the viewpoint of sufficiently suppressing the generation of formaldehyde when forming a foamed sheet, the polymer preferably does not have an N-methylol group. More specifically, the polymer preferably does not contain a monomer unit having an N-methylol group. Here, examples of the monomer having an N-methylol group include N-methylolacrylamide and N-methylolmethacrylamide.

[0048] And the polymer preferably has the following properties.

[0049] Specifically, the glass transition temperature of the polymer is preferably -10°C or lower, more preferably -13°C or lower, still more preferably -17°C or lower, and particularly preferably -20°C or lower. If the glass transition temperature of the polymer is -10°C or lower, it is possible to satisfactorily adhere the self-adhesive laminate provided with the foamed sheet to the adherend while sufficiently ensuring the self-adhesion of the foamed sheet. Thereby, it is possible to prevent moisture from entering between the adherend and the foamed sheet. Therefore, the water resistance of the self-adhesive laminate provided with the foamed sheet can be enhanced. In addition, the lower limit value of the glass transition temperature of the polymer is not particularly limited, but from the viewpoint of sufficiently suppressing the resin residue on the adherend of the self-adhesive laminate provided with the foamed sheet, it is preferably -40°C or higher. The glass transition temperature of the polymer can be obtained, for example, by measuring the glass transition temperature of a film obtained by drying a polymer latex containing the polymer using a differential scanning calorimeter in accordance with JIS K7121. As the differential scanning calorimeter, for example, DSC7000X (manufactured by Hitachi High-Tech Science Corporation) can be used.

[0050] Also, the gel fraction of the polymer is preferably 95% by mass or less, more preferably 93% by mass or less. If the gel fraction is 95% by mass or less, a foamed sheet having appropriate self-adhesion and excellent smoothness can be obtained. The lower limit value of the gel fraction of the polymer is not particularly limited, but it can be, for example, 50% by mass or more, and can be 70% by mass or more. Incidentally, the gel fraction of the polymer can be measured, for example, by the following method. First, the polymer is applied onto a polyethylene terephthalate (PET) film with a thickness of 50 μm using an applicator with a thickness of 250 μm, and dried at room temperature for 24 hours to obtain a resin film. Using this film as a sample, a predetermined amount (X) (about 500 mg) is precisely weighed, immersed in 100 mL of ethyl acetate at room temperature for 3 days, then the insoluble matter is filtered through a 200-mesh wire mesh, air-dried at room temperature for 15 hours, then dried at 100 °C for 2 hours, cooled at room temperature, and then the weight (Y) of the sample is measured. Then, the gel fraction is calculated by substituting X and Y into the following formula. Gel fraction (%) = (Y) / (X) × 100

[0051] The polymerization method for obtaining the above-described polymer is not particularly limited, and may be any of solution polymerization, emulsion polymerization, suspension polymerization, bulk polymerization, etc., or other methods. There are also no particular restrictions on the types and amounts of polymerization initiators, emulsifiers, dispersants, etc. used in the polymerization. There are no particular restrictions on the addition methods of monomers, polymerization initiators, emulsifiers, dispersants, etc. during the polymerization. Also, there are no restrictions on the polymerization temperature, pressure, stirring conditions, etc.

[0052] [Metal-containing oxidized cellulose nanofibers] Metal-containing oxidized cellulose nanofibers containing a metal other than sodium in the form of a salt are components that impart deodorizing properties to the foamed sheet. The metal-containing oxidized cellulose nanofibers are not particularly limited as long as they have deodorizing properties. In addition, the above metal-containing oxidized cellulose nanofibers can impart strength to the foamed sheet. Therefore, while maintaining the strength of the foamed sheet, the foamed sheet can be made less dense. If the foamed sheet is made less dense (i.e., more bubbles are formed in the foamed sheet), the contact area between the metal-containing oxidized cellulose nanofibers and the outside air increases, so the deodorizing power of the foamed sheet improves. Therefore, by including the above metal-containing oxidized cellulose nanofibers, it is also possible to improve the deodorizing properties of the foamed sheet while maintaining the strength of the foamed sheet.

[0053] Here, the metal other than sodium contained in the metal-containing oxidized cellulose nanofibers can be a metal according to the properties to be imparted to the metal-containing oxidized cellulose nanofibers. From the perspective of deodorizing properties, the metal other than sodium can be, for example, at least one selected from metals in Groups 2 to 14 and Periods 3 to 6 in the periodic table; more preferably, at least one selected from the group consisting of magnesium, aluminum, calcium, titanium, chromium, manganese, iron, cobalt, nickel, copper, zinc, silver, tin, barium, and lead; still more preferably, at least one selected from the group consisting of aluminum, calcium, iron, cobalt, copper, zinc, and silver; particularly preferably, at least one selected from the group consisting of silver, zinc, and copper. Note that the metal-containing oxidized cellulose nanofibers containing copper and silver (copper-containing oxidized cellulose nanofibers, silver-containing oxidized cellulose nanofibers) are particularly excellent in deodorizing properties against sulfur-based malodorous gases such as hydrogen sulfide and methyl mercaptan.

[0054] And the amount of the metal other than sodium in the metal-containing oxidized cellulose nanofibers is not limited as long as the desired properties can be imparted to the resulting foamed sheet. For example, in the above metal-containing carboxylated cellulose nanofibers, the metal other than sodium preferably exists at a ratio of 1 / 3 or more of the molar amount of the carboxyl groups of the carboxylated cellulose nanofibers, and more preferably at a ratio of 1 / 2 or more. The greater the content ratio of the metal other than sodium in the metal-containing oxidized cellulose nanofibers, the more the deodorizing properties of the resulting foamed sheet can be improved.

[0055] Note that the metal in the above metal-containing oxidized cellulose nanofibers can be qualitatively and quantitatively analyzed by the ICP-AES method according to the methods described in, for example, JP-A-2016-141777 or JP-A-2019-199622.

[0056] And the metal-containing oxidized cellulose nanofiber is preferably a metal-containing carboxylated cellulose nanofiber. This is because the metal-containing carboxylated cellulose nanofiber has excellent dispersibility, and even when the blending amount is small, it can impart desired properties such as deodorizing properties to the foamed sheet well.

[0057] Here, the carboxylated cellulose nanofiber constituting the metal-containing carboxylated cellulose nanofiber is one in which the primary hydroxyl group at the 6-position of the β-glucose unit of the raw material cellulose is oxidized to a carboxyl group via an aldehyde group. From the viewpoint of sufficiently imparting desired properties to the metal-containing carboxylated cellulose nanofiber, in the carboxylated cellulose nanofiber, it is preferable that the primary hydroxyl group is oxidized to a carboxyl group by 50 mol% or more, more preferably 70 mol% or more, still more preferably 90 mol% or more.

[0058] The amount of carboxyl groups in the metal-containing carboxylated cellulose nanofiber can be measured according to the method described in JP-A-2016-141777 or JP-A-2019-199622.

[0059] And the metal-containing oxidized cellulose nanofiber preferably has the following properties.

[0060] Specifically, the number average fiber diameter of the metal-containing oxidized cellulose nanofiber is preferably 100 nm or less, more preferably 50 nm or less, still more preferably 30 nm or less, and particularly preferably 10 nm or less. This is because the metal-containing oxidized cellulose nanofiber having a number average fiber diameter of 100 nm or less has excellent dispersibility, and even when the blending amount is small, it can impart desired properties such as deodorizing properties to the foamed sheet well.

[0061] In addition, the metal-containing oxidized cellulose nanofibers preferably have a number-average fiber length of 50 nm or more and 2000 nm or less, more preferably 70 nm or more and 1500 nm or less, still more preferably 100 nm or more and 1000 nm or less, and particularly preferably 400 nm or more and 600 nm or less. If the number-average fiber length is 50 nm or more, sufficiently high mechanical strength can be imparted to the foamed sheet. Further, if the number-average fiber length is 2000 nm or less, the dispersibility of the metal-containing oxidized cellulose nanofibers can be ensured.

[0062] The number-average fiber length of the metal-containing oxidized cellulose nanofibers can be adjusted, for example, by changing the number-average fiber length of the natural cellulose used as a raw material, the oxidation treatment conditions, and the conditions for dispersing (defibrating) the carboxylated cellulose nanofibers after the oxidation treatment. Specifically, if the time of the dispersion treatment (defibrating treatment) is lengthened, the number-average fiber length can be shortened.

[0063] The number-average fiber length of the metal-containing oxidized cellulose nanofibers can be measured, for example, by measuring the fiber lengths of 5 or more metal-containing oxidized cellulose nanofibers using an atomic force microscope and calculating the average value of the obtained measurement values. As the atomic force microscope, for example, Dimension FastScan AFM (manufactured by BRUKER, Tapping mode) can be used.

[0064] In addition, the metal-containing oxidized cellulose nanofibers preferably have an average degree of polymerization (average value of the number of glucose units contained in the cellulose molecule) of 100 or more and 2000 or less, more preferably 300 or more and 1500 or less, still more preferably 500 or more and 1000 or less, and particularly preferably 500 or more and 700 or less. If the average degree of polymerization is 100 or more, sufficiently high mechanical strength can be imparted to the foamed sheet. Further, if the average degree of polymerization is 2000 or less, the dispersibility of the metal-containing oxidized cellulose nanofibers can be ensured.

[0065] The average degree of polymerization of the metal-containing oxidized cellulose nanofibers can be adjusted by changing the average degree of polymerization of the natural cellulose used as the raw material, the oxidation treatment conditions, the conditions for dispersing (defibrating) the carboxylated cellulose nanofibers after the oxidation treatment, and the like.

[0066] The average degree of polymerization of the metal-containing oxidized cellulose nanofibers can be measured, for example, in accordance with “Isogai, A., Mutoh, N., Onabe, F., Usuda, M., “Viscosity measurements of cellulose / SO 2- amine-dimethylsulfoxide solution”, Sen’i Gakkaishi, 45, 299-306 (1989).”.

[0067] And the metal-containing oxidized cellulose nanofibers containing a metal other than sodium described above in the form of a salt can be produced, for example, according to the methods described in JP-A-2016-141777 and JP-A-2019-199622. Note that the metal-containing oxidized cellulose nanofibers containing a metal other than sodium produced as described above are usually obtained as a dispersion liquid dispersed in a dispersion medium such as water.

[0068] Also, from the viewpoint of further achieving both high adsorption properties and deodorizing properties in the foamed sheet, the content of the above metal-containing oxidized cellulose nanofibers in the foamed sheet is preferably 0.1 part by mass or more, more preferably 0.3 part by mass or more, still more preferably 0.4 part by mass or more, based on 100 parts by mass of the polymer, and preferably 1.0 part by mass or less, more preferably 0.9 part by mass or less, still more preferably 0.8 part by mass or less.

[0069] [Other Additives] The foamed sheet can optionally contain various additives for improving processability during the production process of the foamed sheet and for improving the performance of the foamed sheet. Examples of such additives include crosslinking agents, foam stabilizers such as higher fatty acid salts and surfactants, foaming aids, thickeners, fillers, preservatives, fungicides, gelling agents, flame retardants, anti-aging agents, antioxidants, pigments, dyes, tackifiers, conductive compounds, water repellents, oil repellents, and the like. Note that specific examples of the other additives described above are not particularly limited, and known additives, for example, those described in WO 2016 / 147679, can be used.

[0070] Here, the crosslinking agent is not particularly limited as long as it can form a crosslinked structure with the above-described polymer (particularly, the unsaturated carboxylic acid monomer unit of the above-described polymer). Examples of such crosslinking agents include carbodiimide-based crosslinking agents; epoxy-based crosslinking agents; oxazoline-based crosslinking agents; polyfunctional isocyanate-based crosslinking agents such as tolylene diisocyanate, trimethylolpropane tolylene diisocyanate, diphenylmethane triisocyanate; metal salt-based crosslinking agents; metal chelate-based crosslinking agents; peroxide-based crosslinking agents; and the like. Among them, epoxy-based crosslinking agents are preferably used, and compounds having two or more epoxy groups in one molecule are more preferably used. And as the epoxy-based crosslinking agent, fatty acid polyglycidyl ether, glycerol polyglycidyl ether, and ethylene glycol diglycidyl ether are preferred.

[0071] Here, the epoxy-based crosslinking agent may be synthesized by a known method or a commercially available product may be used. Examples of commercially available epoxy-based crosslinking agents include "Ricobond (registered trademark)" manufactured by Japan Coating Resin Co., Ltd. The epoxy crosslinking agent forms a crosslinked structure within or between polymer molecules through the reaction of the epoxy groups it has with functional groups in the above polymer (for example, carboxylic acid groups derived from unsaturated carboxylic acid monomer units). By using an epoxy crosslinking agent, a foamed sheet having appropriate self-adhesion and excellent strength can be formed. Therefore, if an epoxy crosslinking agent is used as the crosslinking agent, the resin residue on the adherend of the foamed sheet can be suppressed.

[0072] In the present invention, it is preferably not to use crosslinking agents that cause the generation of formaldehyde, such as melamine-formaldehyde resins, urea-formaldehyde resins, and phenol-formaldehyde resins.

[0073] Here, the blending amount of the crosslinking agent is preferably 0.5 part by mass or more, more preferably 1 part by mass or more, still more preferably 3 part by mass or more, preferably 20 parts by mass or less, and more preferably 10 parts by mass or less per 100 parts by mass of the above-mentioned polymer. When the blending amount of the crosslinking agent is within the above-mentioned range, a foamed sheet with appropriately maintained strength and elasticity can be obtained. Therefore, when the pressure applied to the foamed sheet is released, the foam cells in the crushed foamed sheet can recover to their original shape. And while ensuring the self-adhesion of the foamed sheet, the resin residue on the adherend of the foamed sheet can be sufficiently suppressed.

[0074] Also, as the foam stabilizer, fatty acid ammonium such as ammonium stearate; sulfonic acid type anionic surfactants such as alkyl sulfosuccinate; quaternary alkyl ammonium chloride; alkyl betaine amphoterics; and fatty acid alkanolamines can be used.

[0075] Furthermore, as the thickener, acrylic polymers such as sodium polyacrylate; inorganic compound fine particles such as fine silica; and reactive inorganic compounds such as magnesium oxide can be used.

[0076] [Properties of the Foamed Sheet] And the self - adsorbing foam sheet preferably has the following properties.

[0077] The density of the foam sheet is not particularly limited, but it is preferably 0.3 g / cm 3 or more, more preferably 0.4 g / cm 3 or more, and preferably 0.7 g / cm 3 or less, more preferably 0.6 g / cm 3 or less. If the density of the foam sheet is 0.3 g / cm 3 or more, the strength of the foam sheet can be ensured. On the other hand, if the density of the foam sheet is 0.7 g / cm 3 or less, while ensuring the deodorizing property of the foam sheet, the air - bleeding property (the ability to easily remove the air pockets remaining between the foam sheet and the adherend) can be sufficiently enhanced.

[0078] The thickness of the foam sheet is preferably 30 μm or more, more preferably 50 μm or more, still more preferably 100 μm or more, and preferably 3 mm or less, more preferably 1 mm or less, still more preferably 500 μm or less, and particularly preferably 400 μm or less. If the thickness of the foam sheet is 30 μm or more, the deodorizing property and mechanical strength of the foam sheet can be sufficiently ensured. On the other hand, if the thickness of the foam sheet is 3 mm or less, a self - adsorbing laminate excellent in repeatability of pasting (rework performance) can be obtained.

[0079] The foamed sheet preferably contains continuous bubbles in which a plurality of bubbles communicate with each other. If the foamed sheet contains such continuous bubbles, the air trapped between the foamed sheet and the adherend can be easily removed to the outside of the foamed sheet through the continuous bubbles, so that the air permeability of the foamed sheet is further improved, and the foamed sheet can be neatly and easily attached to the adherend. Further, if the foamed sheet contains such continuous bubbles, the contact area with the outside air increases and more odor components can be deodorized, so that the deodorizing property of the foamed sheet is further improved. From the viewpoint of further improving the air permeability and deodorizing property, the continuous bubbles in the foamed sheet preferably include continuous bubbles extending in the planar direction of the foamed sheet. The continuous bubbles in the foamed sheet can usually be confirmed by observing a cross-section of the foamed sheet with, for example, a laser microscope, a digital microscope, a scanning electron microscope, or the like.

[0080] <Base material> As the base material, any base material can be used as long as the air permeability is more than 0 cm 3 / cm 2 / second and the basis weight is 40 g / m 2 or more.

[0081] Among them, as the base material, it is preferable to use a fibrous base material such as a woven fabric, a non-woven fabric, or paper. From the viewpoint of achieving both high deodorizing property and strength of the self-adhesive laminate, as the fibrous base material, for example, natural fibers such as cotton, silk, and pulp; polyamide-based synthetic fibers; polyester-based synthetic fibers; polypropylene-based synthetic fibers; polyvinyl chloride-based synthetic fibers; polyvinyl alcohol-based synthetic fibers; semi-synthetic fibers such as acetate; regenerated man-made fibers such as rayon; and a sheet-like base material composed of a mixture or laminate of these fibers are preferably used. From the viewpoint of further enhancing the heat resistance, it is more preferable to use a sheet-like base material containing PET fibers, and it is even more preferable to use a non-woven fabric containing PET fibers.

[0082] Here, from the viewpoint of further enhancing the deodorizing property of the self-adhesive laminate, the air permeability of the base material is 15 cm 3 / cm 2It is preferably at least / second, and 30 cm 3 / cm 2 It is more preferably at least / second, and 50 cm 3 / cm 2 It is even more preferably at least / second. The air permeability of the base material is usually 800 cm 3 / cm 2 / second or less.

[0083] Also, from the viewpoint of suppressing the permeation of the material used for forming the foamed sheet through the base material, the basis weight of the base material is preferably 45 g / m 2 or more. From the viewpoint of facilitating the permeation of the gas containing the odor substance and enhancing the deodorizing property of the self-adsorbing laminate, the basis weight of the base material is preferably 90 g / m 2 or less, and more preferably 60 g / m 2 or less.

[0084] And, from the viewpoint of achieving both high improvement in the deodorizing property of the self-adsorbing laminate and high suppression of the permeation of the material used for forming the foamed sheet at a high level, the thickness of the base material is preferably 10 μm or more, more preferably 130 μm or more, even more preferably 150 μm or more, preferably 500 μm or less, and more preferably 350 μm or less. In addition, if both the basis weight and the thickness of the base material are within the above ranges, the tensile strength of the base material can be strengthened.

[0085] (Method for manufacturing a self-adsorbing laminate) The method for manufacturing the self-adsorbing laminate of the present invention includes a step of foaming a composition for a self-adsorbing foamed sheet to obtain a foamed composition (foaming step), and a step of forming the foamed composition into a sheet shape on a base material (sheet-forming step). The laminate obtained through the above-described steps is not particularly limited. For example, after attaching a separator film to the surface having self-adsorbing properties (i.e., the surface on the foamed sheet side), it can be wound by a winder and processed into a convenient size by cutting with a press cutter, a slitter, etc.

[0086] <Foaming step> In the foaming step, a composition for a self - adsorbing foam sheet (hereinafter sometimes referred to as "the composition for the foam sheet") is foamed to obtain a foamed composition.

[0087] [Composition for self - adsorbing foam sheet] Here, the composition for the foam sheet contains a polymer and a metal - containing oxidized cellulose nanofiber containing a metal other than sodium in the form of a salt, and optionally further contains a solvent and other additives.

[0088] And as the polymer, the metal - containing oxidized cellulose nanofiber containing a metal other than sodium in the form of a salt, and other additives that can be contained in the composition for the foam sheet, those similar to those described above for the self - adsorbing foam sheet of the self - adsorbing laminate of the present invention can be used. Also, their preferred forms and blending ratios can be the same as those described above for the self - adsorbing foam sheet of the self - adsorbing laminate of the present invention.

[0089] Note that the polymer can be used in solid form for the preparation of the composition for the foam sheet, but it is preferably used in the state of a latex containing a polymer (polymer latex), such as a latex obtained by emulsion polymerization or a latex obtained by post - emulsifying the polymer, for the preparation of the composition for the foam sheet. This is because the operation is easy when mixing the polymer with the oxidized cellulose nanofiber containing a metal other than sodium in the form of a salt, the optionally used solvent, and other additives, and it is also convenient for foaming the resulting composition for the foam sheet. Here, when the polymer is used in the form of a polymer latex for the preparation of the composition for the foam sheet, from the viewpoint of maintaining the density of the resulting foam sheet, the solid content concentration of the polymer latex is preferably 40% by mass or more, more preferably 45% by mass or more, still more preferably 50% by mass or more, particularly preferably 52% by mass or more, preferably 70% by mass or less, and more preferably 58% by mass or less.

[0090] In addition, the metal-containing oxidized cellulose nanofibers can be used in the preparation of a foamed sheet composition in the form of a dispersion liquid dispersed in a dispersion medium such as water. In this dispersion liquid, the metal-containing oxidized cellulose nanofibers are preferably highly dispersed at a level where the number-average fiber diameter is 100 nm or less, more preferably 2 nm or more and 50 nm or less, still more preferably 2 nm or more and 10 nm or less, and particularly preferably 2 nm or more and 5 nm or less. Therefore, by using the said dispersion liquid, a foamed sheet composition capable of obtaining a foamed sheet excellent in deodorizing effect can be favorably obtained. Specifically, if a dispersion liquid containing metal-containing oxidized cellulose nanofibers is added to the above-described polymer or polymer latex as it is and the resulting mixture is stirred, a foamed sheet composition in which the metal-containing oxidized cellulose nanofibers are sufficiently dispersed can be favorably obtained. Further, when a dispersion liquid containing metal-containing oxidized cellulose nanofibers is added little by little to the stirred polymer or polymer latex using a pipette or the like, aggregation of the metal-containing oxidized cellulose nanofibers can be prevented, which is preferable. Here, the solid content concentration of the metal-containing cellulose nanofibers in the dispersion liquid is preferably 0.1% or more and 2.0% or less. If the solid content concentration is 0.1% or more, an increase in the content of a dispersion medium such as water in the resulting foamed sheet composition and a decrease in the viscosity of the composition can be prevented, and a smoother and more uniform sheet can be formed. On the other hand, if the solid content concentration is 2.0% or less, pseudo-gelation of the dispersion liquid into a jelly state can be prevented, and the dispersibility of the metal-containing cellulose nanofibers in the resulting foamed sheet composition can be further improved. In addition, when using solid metal-containing oxidized cellulose nanofibers, the above dispersion liquid may be dried by known means.

[0091] In addition, the solvent that the composition for a foamed sheet may optionally contain is not particularly limited, but water is preferred. Here, when water is used as the solvent, the water contained in the composition for a foamed sheet may be, for example, water derived from a polymer latex and / or water derived from an aqueous dispersion of a metal-containing cellulose nanofiber containing a metal other than sodium in the form of a salt. Further, the water contained in the composition for a foamed sheet may be water derived from other additives.

[0092] When the composition for a foamed sheet contains a solvent (in the form of a dispersion in which the metal-containing cellulose nanofiber is dispersed), the viscosity of the composition for a foamed sheet is preferably 800 mPa·s or more and 10,000 mPa·s or less, more preferably 900 mPa·s or more and 8,000 mPa·s or less, and even more preferably 1,000 mPa·s or more and 7,500 mPa·s or less. If the viscosity of the composition for a foamed sheet is 800 mPa·s or more, it is possible to prevent dripping of the liquid and difficulty in controlling the thickness when applying the foamed composition formed from the composition for a foamed sheet onto a substrate to form a foamed sheet. On the other hand, if the viscosity of the composition for a foamed sheet is 10,000 mPa·s or less, it is not difficult to control the expansion ratio by mechanical foaming when forming the foamed sheet. The viscosity of the composition for a foamed sheet can be measured at a temperature of 23°C using a B-type viscometer.

[0093] Also, the pH of the composition for the foamed sheet is preferably 5 or more, more preferably 7 or more, still more preferably 8 or more, and preferably 10 or less, more preferably 9.7 or less, still more preferably 9.5 or less. If the pH of the composition for the foamed sheet is 5 or more, precipitation, aggregation of nanofibers, and sedimentation due to aggregation of the removed metal ions can be favorably prevented, which is caused by the metal of the metal-containing cellulose nanofiber containing a metal other than sodium in the form of a salt being removed to become a carboxylic acid. On the other hand, if the pH of the composition for the foamed sheet is 10 or less, a decrease in the strength of the foamed sheet caused by the difficulty of the crosslinking reaction to proceed when a crosslinking agent is used can be favorably prevented. Incidentally, the pH of the composition for the foamed sheet can be measured at a temperature of 23 °C using a pH meter.

[0094] And the composition for the foamed sheet can be produced by mixing a polymer and a metal-containing oxidized cellulose nanofiber containing a metal other than sodium in the form of a salt with a solvent and other additives used as desired by an arbitrary method.

[0095] For example, when using a polymer latex in preparing the composition for the foamed sheet, a metal-containing oxidized cellulose nanofiber containing a metal other than sodium in the form of a salt and other additives optionally used can be added to this polymer latex and mixed by a known method.

[0096] Also, for example, when using a dispersion of a metal-containing oxidized cellulose nanofiber containing a metal other than sodium in the form of a salt in preparing the composition for the foamed sheet, a solid polymer or a polymer latex and other additives optionally used can be added to this dispersion and mixed by a known method.

[0097] Furthermore, for example, when no solvent is used in preparing the composition for the foamed sheet, a solid polymer, a metal-containing oxidized cellulose nanofiber containing a metal other than sodium in the form of a salt, and optionally other solid additives may be mixed by a known method, such as using a known roll, Henschel mixer, kneader, etc.

[0098] In addition, from the viewpoint of favorably dispersing the metal-containing oxidized cellulose nanofiber containing a metal other than sodium in the form of a salt in the composition for the foamed sheet, a dispersion (for example, an aqueous dispersion) of the metal-containing oxidized cellulose nanofiber containing a metal other than sodium in the form of a salt is added to the polymer latex under stirring to obtain a mixed solution, and then, optionally, other additives are added to the mixed solution and further mixed by a known method. Among the other additives, those that increase the viscosity in the system, such as crosslinking agents and thickeners, are preferably added later so that the composition in the system is kept uniform.

[0099] [Foaming] As a method for foaming the composition for the foamed sheet, mechanical foaming is usually employed. The foaming ratio may be adjusted as appropriate, but is usually 1.2 times or more and 5 times or less, preferably 1.5 times or more and 4 times or less. The method of mechanical foaming is not particularly limited, but it can be carried out by mixing a certain amount of air into the dispersion of the composition for the foamed sheet and continuously or batchwise stirring it with an oximixer, a whipper, etc. The foamed dispersion thus obtained becomes creamy. By forming pores by the above mechanical foaming, a foamed sheet excellent in air permeability can be finally obtained. Note that when the foaming ratio is 1.2 times or more, it is possible to prevent the decrease in air permeability, and when it is 5 times or less, it is possible to prevent the decrease in the strength of the foamed sheet.

[0100] <Sheet-forming step> In the sheet-forming step, the foamed composition obtained in the above foaming step is formed into a sheet shape on a substrate, and the sheet-shaped foamed composition is solidified as necessary to form a foamed sheet on the substrate.

[0101] [Base material] Here, as the base material, the air permeability is more than 0 cm 3 / cm 2 / second, and a base material with a basis weight of 40 g / m 2 or more is used. Specifically, as the base material, the same base material as described above for the self-adhesive laminate of the present invention can be used. In this way, if a base material with an air permeability of more than 0 cm 3 / cm 2 / second is used, the deodorizing property of the obtained self-adhesive laminate can be enhanced. Further, if the basis weight of the base material is 40 g / m 2 or more, even when a breathable base material is used, the permeation of the foaming composition through the base material can be suppressed, the fouling of the manufacturing apparatus by the foaming composition and the reduction of the yield can be suppressed, and the tensile strength of the base material can be sufficiently ensured.

[0102] [Sheet formation] The method of forming the foaming composition into a sheet shape on the base material is not particularly limited. Suitable methods include, for example, a method of applying the foaming composition in a sheet shape on the base material. And, as a method of applying the foaming composition on the base material or the like, for example, a method using a generally known coating apparatus such as a roll coater, a reverse roll coater, a screen coater, a doctor knife coater, a comma knife coater can be used.

[0103] The solidification of the foaming composition, which is carried out as necessary, is performed, for example, by crosslinking the polymer of the foaming composition formed into a sheet shape. The method of crosslinking the polymer is not limited, but a method of heat-drying the foaming composition is preferable. The heat-drying method is not particularly limited as long as it can dry the foaming composition on the base material or the like and crosslink the polymer, and a known drying furnace (for example, a hot air circulation type oven, a hot oil circulation hot air chamber, a far-infrared heater chamber) can be used. The drying temperature can be, for example, 60°C or higher and 180°C or lower. Further, it is preferable to perform multi-stage drying in which drying is not carried out at a constant temperature, but drying is performed from the inside at a low temperature in the initial stage of drying, and sufficient drying is performed at a higher temperature in the later stage of drying.

[0104] In this way, a self-adhesive laminate provided with a self-adhesive foam sheet in which a sheet-like foam composition is solidified on a base material or the like is obtained.

[0105] (Use of the laminate) On the base material surface of the self-adhesive laminate of the present invention, printing can be performed, for example, by offset printing, seal printing, flexographic printing, silk screen printing, gravure printing, laser printer, thermal transfer printer, inkjet printer, or the like. The laminated sheet printed on the base material surface can be advantageously used for outdoor applications such as sales promotion cards, so-called POP cards (posters, stickers, displays, etc.), horticultural POPs (clip labels, etc.), road signs (funeral, housing display sites, etc.), display boards (no entry, forest road work, etc.), and indoor applications such as adhering to wallpapers, floor materials, and wall materials.

Examples

[0106] Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. Further, in a polymer produced by polymerizing a plurality of types of monomers, the ratio of a monomer unit formed by polymerizing a certain monomer in the polymer is usually the same as the ratio (charge ratio) of the certain monomer in all the monomers used for the polymerization of the polymer, unless otherwise specified. And various measurements and evaluations in the examples and comparative examples were carried out according to the following methods.

[0107] <Thickness of the base material> For 8 base materials cut out into a 50 mm × 50 mm square, the arithmetic mean value of the thickness measured using a thickness gauge (manufactured by Ozaki Seisakusho, PEACOK MODEL H) was taken as the thickness of the base material. <Grammage of the base material> For 8 base materials cut out into a 50 mm × 50 mm square, the grammage (={arithmetic mean value of weight / (50 mm × 50 mm)}) was calculated from the arithmetic mean value of the weights measured using a balance (manufactured by A&D Company, BM-252). <Air permeability of the base material> It was measured by the frazil method using a frazil tester in accordance with JIS L1913. <Coatability of the foam composition> After manufacturing the laminate, the surface of the automatic coater was visually observed. And the coatability was evaluated according to the following criteria. A: The foam composition does not pass through the base material, and no stain is observed on the surface of the automatic coater B: The foam composition passes through the base material, and stains are observed on the surface of the automatic coater <Deodorizing property of the self-adhesive laminate> The produced laminate was cut out into 100 mm × 100 mm × thickness, and the foam sheet side was pasted on a soda glass of 120 mm × 120 mm × 1 mm to obtain a sample. The sample was put into a sampling pack (manufactured by GL Sciences, SMART BAG PA AA-5), and the mouth was heat-sealed and sealed. The sampling pack was degassed using a vacuum pump, 3 L of a gas with a predetermined concentration (hydrogen sulfide gas: 80 mass ppm) was sealed into the sampling pack, and then the gas concentration (mass ppm) in the pack was measured using a gas detector tube (gas detector tube manufactured by Gastech) at a predetermined time. The faster the gas concentration decreases in a short time, the better the deodorizing property is indicated.

[0108] (Example 1) <Preparation of polymer latex> To 27.0 parts by mass of deionized water, a monomer mixture consisting of 64 parts by mass of ethyl acrylate, 12 parts by mass of 2-ethylhexyl acrylate, 12 parts by mass of n-butyl acrylate, 9 parts by mass of acrylonitrile, 2 parts by mass of styrene, and 1 part by mass of acrylic acid, and 0.4 parts by mass of sodium polyoxyethylene alkyl sulfate (manufactured by Kao Corporation, Latemul E-118B) were mixed and stirred to obtain a monomer emulsion. Next, separately from the above, a glass reaction vessel equipped with a reflux condenser, a dropping funnel, a thermometer, a nitrogen inlet, and a stirrer was prepared. 43.0 parts by mass of deionized water and 0.2 parts by mass of sodium polyoxyethylene alkyl sulfate were placed in this glass reaction vessel, and while stirring, the temperature was raised to 80°C. Then, while maintaining the temperature at 80°C, 0.3 parts by mass of ammonium persulfate dissolved in 5.7 parts by mass of deionized water was added, and subsequently, the monomer emulsion obtained above was gradually added over 4 hours. After the addition was completed, stirring was continued for another 4 hours, and then it was cooled to terminate the reaction, obtaining a reaction mixture. The polymerization conversion rate at this time was 98% or more. The obtained reaction mixture was adjusted to pH 5.0 with 5% aqueous ammonia, and after adding 2.5 parts by mass of polyoxyethylene lauryl ether (manufactured by Kao Corporation, Emulgen 120), concentration was carried out to obtain a polymer latex with a solid content concentration of 58% by mass. <Preparation of Copper-Containing TEMPO Oxidized Cellulose Nanofiber Aqueous Dispersion> 1 g equivalent of softwood bleached kraft pulp by dry weight, 5 mmol of sodium hypochlorite, 0.1 g (1 mmol) of sodium bromide, and 0.016 g (1 mmol) of TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) were dispersed in 100 mL of water, gently stirred at room temperature for 4 hours, and washed with distilled water to obtain TEMPO-catalyzed oxidized pulp (oxidized cellulose). The amount of carboxyl groups in the obtained TEMPO-catalyzed oxidized pulp was 1.4 mmol / g. Thereafter, distilled water was added to the undried TEMPO-catalyzed oxidized pulp to prepare an aqueous dispersion with a solids concentration of 0.1%. Then, using a homogenizer (manufactured by Microtech Nition, Hiscotron), the aqueous dispersion was homogenized at 7.5 × 1000 rpm for 2 minutes. Using an ultrasonic homogenizer (manufactured by Nissei, Ultrasonic Generator), while cooling the periphery of the container with ice, fibrillation treatment was performed at V-LEVEL4 and TIP26D for 4 minutes to obtain an aqueous dispersion containing TEMPO-carboxylated cellulose nanofibers as TEMPO-oxidized cellulose nanofibers. Thereafter, from the TEMPO-carboxylated cellulose nanofiber aqueous dispersion, centrifugation (12000G (120 × 100 rpm / g), 10 minutes, 12°C) was performed using a centrifuge (manufactured by Sakuma, M201-1VD, angle rotor 50F-8AL) to remove the unfibrillated components, and a transparent liquid, an aqueous dispersion of TEMPO-carboxylated cellulose nanofibers with a concentration of 0.1% by mass, was obtained. Note that the TEMPO-carboxylated cellulose nanofibers contained sodium derived from the co-oxidizing agent in the form of a salt. Next, 1 mL of 1 M hydrochloric acid was added to 100 mL of the TEMPO-carboxylated cellulose nanofiber aqueous dispersion while stirring to adjust the pH to 1. Then, stirring was continued for 60 minutes. Thereafter, the TEMPO-carboxylated cellulose nanofibers gelled by the addition of hydrochloric acid were recovered by centrifugation (12000G), and the recovered TEMPO-carboxylated cellulose nanofibers were washed sequentially with 1 M hydrochloric acid and a large amount of distilled water. Next, 100 mL of distilled water was added to obtain an aqueous dispersion of hydrogen-substituted TEMPO-carboxylated cellulose nanofibers with a concentration of 0.1% by mass in which the hydrogen-substituted TEMPO-carboxylated cellulose nanofibers were dispersed. Note that when the carboxyl groups on the surface of the hydrogen-substituted TEMPO-carboxylated cellulose nanofibers were measured by FT-IR (manufactured by JASCO, FT / IR-6100) according to Biomacromolecules (2011, Vol. 12, pp. 518 - 522), more than 90% were substituted with the carboxylic acid type. Then, 50 g of the hydrogen-substituted TEMPO carboxylated cellulose nanofiber aqueous dispersion with a concentration of 0.1% by mass was stirred, and 18 g of an aqueous copper(II) acetate solution with a concentration of 0.1% by mass was added thereto, and stirring was continued at room temperature for 3 hours. Thereafter, the carboxylated cellulose nanofibers gelled by the addition of the aqueous copper(II) acetate solution were collected by centrifugation (12,000 G (120×100 rpm / g), 10 minutes, 12°C) using a centrifuge (manufactured by SAKUMA, M201-1VD, angle rotor 50F-8AL). After that, the recovered cellulose nanofibers were washed with an aqueous copper(II) acetate solution with a concentration of 0.1% by mass, and then the recovered cellulose nanofibers were washed with a large amount of distilled water. Thereafter, 50 mL of distilled water was added, and using an ultrasonic homogenizer (manufactured by nissei, Ultrasonic Generator), while cooling the periphery of the container with ice, ultrasonic treatment (2 minutes) was performed at V-LEVEL 4 and TIP26D to disperse the TEMPO carboxylated cellulose nanofibers substituted with copper. Thereafter, the undispersed components were removed from the aqueous dispersion of the TEMPO carboxylated cellulose nanofibers substituted with copper by centrifugation (12,000 G (120×100 rpm / g), 10 minutes, 12°C) using a centrifuge (manufactured by SAKUMA, M201-1VD, angle rotor 50F-8AL). Thus, an aqueous dispersion of copper-containing TEMPO-oxidized cellulose nanofibers (hereinafter, also simply referred to as "TOCN-Cu") with a solid content concentration of 0.1% by mass was obtained. Thereafter, this aqueous dispersion was concentrated using an evaporator to obtain an aqueous dispersion of TOCN-Cu with a solid content concentration of 0.94% by mass. <Preparation of Foaming Composition> 300 g of the above polymer latex (solid content concentration: 58% by mass) was weighed into a 500 mL disposable cup and stirred (1750 rpm) with a mixer (manufactured by Tokushu Kika Kogyo Co., Ltd., ROBOMICS). While stirring the polymer latex, 18.62 g of the above TOCN-Cu aqueous dispersion (solid content concentration: 0.94% by mass) (TOCN-Cu content based on 100 parts by mass of the polymer: 0.1 part by mass) was gradually added little by little, and stirring was continued for 30 minutes after addition. Then, while stirring the resulting mixture, 12 g of ammonium stearate (manufactured by San Nopco Ltd., Nopco DC-100A, concentration: 30% by mass) as a foam stabilizer, 9 g of fatty acid polyglycidyl ether (manufactured by Japan Coating Resin Co., Ltd., Ricabond EX-8, concentration: 100% by mass) as an epoxy-based crosslinking agent, and 9 g of sodium polyacrylate (manufactured by Toagosei Co., Ltd., Aron A-20L, concentration: 15% by mass) as a thickener were added to the mixture in order. Then, it was stirred for 30 minutes to obtain a composition for a foamed sheet. The solid content concentration of the composition for a foamed sheet was 54% by mass, the viscosity measured at 23°C using a B-type viscometer (manufactured by Lion Corporation, "VISCOTESTER VT-06") was 4300 mPa·s, and the pH measured at 23°C using a pH meter (manufactured by Horiba, pH METER F-52) was 8.69. The composition for a foamed sheet was foamed using a foaming device (manufactured by Tescom Corporation, Hand Mixer THM272) so that the foaming ratio became 2 times, and a foamed composition (foaming liquid) having a density of 0.49 g / cm 3 was obtained. <Production of Self-Adhesive Laminate> The foaming liquid prepared above was applied onto a base material (PET nonwoven fabric) shown in Table 1 using an automatic coater (main body: manufactured by TQC sheen Co., Ltd., AFA-Standard KT-AB4420, applicator: manufactured by Coat Tech Co., Ltd., Multi Applicator MA-250). The PET nonwoven fabric coated with the foaming liquid was put into an oven (manufactured by Yamato Scientific Co., Ltd., DNF400) at 80°C for 80 seconds, then into an oven (manufactured by Yamato Scientific Co., Ltd., DNF400) at 120°C for 120 seconds, and finally into an oven (manufactured by Yamato Scientific Co., Ltd., DNF400) at 140°C for 120 seconds for drying, to obtain a laminate having a foamed layer (thickness: 120 μm, density: 0.43 g / cm 3 ) on the base material. Then, evaluations were conducted on the coatability and deodorizing properties. The results are shown in Table 1.

[0109] (Examples 2 to 6) A laminate was produced and evaluated in the same manner as in Example 1, except that the base material shown in Table 1 (PET nonwoven fabric) was used as the base material. The results are shown in Table 1.

[0110] (Comparative Examples 1 to 2) When attempting to produce a laminate in the same manner as in Example 1, except that the base material shown in Table 1 (PET nonwoven fabric) was used as the base material, the foaming liquid passed through the base material, and the intended foamed sheet could not be formed. Therefore, the evaluation of the deodorizing property was not performed.

[0111] (Comparative Examples 3 to 4) A laminate was produced and evaluated in the same manner as in Example 1, except that the base material shown in Table 1 (synthetic paper or PET film) was used as the base material. The results are shown in Table 1.

[0112]

Table 1

[0113] From Table 1, it can be seen that the laminates of Examples 1 to 6 are excellent in deodorizing property and can be efficiently manufactured. Among them, it can be seen that the laminates of Examples 1 and 2 are particularly excellent in deodorizing property. Further, from Table 1, it can be seen that in Comparative Examples 1 and 2 using base materials with a small basis weight, the laminates cannot be efficiently manufactured. Furthermore, from Table 1, it can be seen that in Comparative Examples 3 and 4 using base materials without air permeability, the deodorizing property cannot be sufficiently enhanced.

Industrial Applicability

[0114] According to the present invention, it is possible to provide a self-adsorbing laminate that is excellent in deodorizing property and can be efficiently manufactured.

Claims

1. A self-adhesive laminate comprising a substrate and a self-adhesive foam sheet, The self-adhesive foam sheet includes a polymer and a metal-containing oxidized cellulose nanofiber containing a metal other than sodium in the form of a salt, and includes open cells in which a plurality of cells are interconnected, the metal other than sodium is at least one selected from the group consisting of silver, zinc, and copper; The self-adhesive laminate of the substrate has an air permeability of 4 cm 3 / cm 2 / sec or more and 800 cm 3 / cm 2 / sec or less and a basis weight of 45 g / m 2 or more and 90 g / m 2 or less.

2. 2. The self-adhesive laminate of claim 1, wherein the polymer comprises (meth)acrylate monomer units.

3. The self-adhesive laminate according to claim 1 or 2, wherein the number average fiber diameter of the metal-containing oxidized cellulose nanofibers is 100 nm or less.

4. The self-adhesive laminate according to any one of claims 1 to 3, wherein the metal-containing oxidized cellulose nanofiber is a metal-containing carboxylated cellulose nanofiber.

5. The self-adhesive laminate according to any one of claims 1 to 4, wherein the substrate contains PET fibers.

6. A step of foaming a composition for a self-adhesive foam sheet, the composition including a polymer and a metal-containing oxidized cellulose nanofiber containing a metal other than sodium in the form of a salt, to obtain a foam composition; A step of forming the foam composition on a substrate into a sheet-like shape containing open cells formed by a plurality of cells communicating with each other; Including, the metal other than sodium is at least one selected from the group consisting of silver, zinc, and copper; 6. The method for producing a self-adhesive laminate according to claim 1, wherein the base material has an air permeability of 4 cm 3 / cm 2 / sec or more and 800 cm 3 / cm 2 / sec or less, and a basis weight of 45 g / m 2 or more and 90 g / m 2 or less.

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