Sulfur-based gas sensor material, molded body, self-adsorbing foam sheet, self-adsorbing laminate, method for manufacturing self-adsorbing laminate, and sulfur-based gas sensor device

Abstract

The object is to provide a novel sulfur-based gas sensor material. [Solution] A sulfur-based gas sensor material containing copper ions. It preferably contains copper-containing oxidized cellulose nanofibers containing copper in the form of a salt. Also, a self-adsorbing foam sheet and a self-adsorbing laminate containing the sulfur-based gas sensor material are provided.

Description

[Technical Field]

[0001] The present invention relates to a sulfur-based gas sensor material. [Background technology]

[0002] Sulfur-based gases, such as hydrogen sulfide and methyl mercaptan, are known to have a foul odor, along with ammonia, and various techniques for deodorizing these gases have been studied. Furthermore, because sulfur-based gases are toxic to the human body, there is a high demand for sensors that can detect the presence of sulfur-based gases.

[0003] In recent years, the use of metal compounds to absorb sulfur-based gases has been studied. For example, Patent Document 1 discloses a battery adhesive for use in batteries containing a sulfide-based solid electrolyte, the battery adhesive including a metal compound and a resin, the metal compound content being a predetermined ratio relative to the total mass of the metal compound and the resin. This patent document describes that as long as the amount of the metal compound is within the predetermined ratio, the adhesive has excellent adhesive strength and can effectively absorb hydrogen sulfide generated within the battery (see, for example, paragraphs

[0010] and

[0041] of the specification of Patent Document 1).

[0004] Patent Document 2 discloses a composition for self-adsorbent foam sheets, which comprises a polymer and metal-containing oxidized cellulose nanofibers containing a metal other than sodium in the form of a salt, with the metal-containing oxidized cellulose nanofibers being present in a predetermined ratio relative to the polymer. It describes that the metal-containing oxidized cellulose nanofibers have deodorizing properties against sulfur-based gases and the like, and therefore the composition can provide a self-adsorbent foam sheet with excellent deodorizing and adsorbent properties (see, for example, paragraphs

[0017] ,

[0051] , and

[0058] of the Patent Document 2 specification). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2022 / 024717 [Patent Document 2] Japanese Patent Application Publication No. 2022-101282 Summary of the Invention [Problem to be solved by the invention]

[0006] The metal compounds and metal-containing oxidized cellulose nanofibers disclosed in the above documents can exhibit absorption and deodorizing effects against sulfur-based gases such as hydrogen sulfide and methyl mercaptan. As a result of further investigation, the present inventors have newly discovered that compounds containing copper ions are particularly suitable for use as sulfur-based gas sensor materials that can detect and visualize the presence of sulfur-based gases, and have completed the present invention. An object of the present invention is to provide the above-mentioned novel sulfur-based gas sensor material. [Means for solving the problem]

[0007] That is, an object of the present invention is to advantageously solve the above-mentioned problems, and the present invention is [1] a sulfur-based gas sensor material containing copper ions.

[0008] [2] Here, the sulfur-based gas sensor material of [1] above preferably contains copper-containing oxidized cellulose, which contains copper in the form of a salt.

[0009] [3] In the sulfur-based gas sensor material [2] above, the copper-containing oxidized cellulose is preferably copper-containing carboxylated cellulose.

[0010] [4] In the sulfur-based gas sensor material of [2] or [3] above, the copper-containing oxidized cellulose is preferably a copper-containing oxidized cellulose nanofiber having a number-average fiber diameter of 100 nm or less. The number average fiber diameter of the copper-containing oxidized cellulose can be measured according to the method described herein.

[0011] [5] In the sulfur-based gas sensor material according to any one of [2] to [4] above, the number-average fiber length of the copper-containing oxidized cellulose is preferably 50 nm or more and 2000 nm or less. The number average fiber length of the copper-containing oxidized cellulose can be measured according to the method described herein.

[0012] [6] In any one of the sulfur-based gas sensor materials [2] to [5] above, the average degree of polymerization of the copper-containing oxidized cellulose is preferably 100 or more and 2000 or less. The average degree of polymerization of copper-containing oxidized cellulose can be measured according to the method described herein.

[0013] [7] The present invention also provides a molded article containing the sulfur-based gas sensor material according to any one of the above [1] to [6].

[0014] [8] The molded article in [7] above is preferably in the form of a sheet.

[0015] [9] Furthermore, the present invention relates to a self-adhesive foam sheet comprising the molded article according to [8] above.

[0016]

[10] The self-adhesive foam sheet described in [9] above has a density of 0.7 g / cm 3 It is preferable that: The density of the self-adhesive foam sheet can be measured according to the method described in the examples of this specification.

[0017]

[11] The self-adhesive foam sheet of [9] or

[10] above preferably has a thickness of 100 μm or more.

[0018]

[12] The present invention also provides a self-adhesive laminate comprising a substrate and the self-adhesive foam sheet according to any one of [9] to

[11] above.

[0019]

[13] The present invention provides a method for producing the self-adhesive laminate of

[12] above, comprising the steps of: foaming a composition for a self-adhesive foam sheet, the composition comprising a polymer and copper-containing oxidized cellulose containing copper in the form of a salt, to obtain a foamed composition; and forming the foamed composition into a sheet on a substrate.

[0020]

[14] The present invention is a sulfur-based gas sensor device comprising the molded article of [7] or [8] above, the self-adsorbent foam sheet of any one of [9] to

[11] above, or the self-adsorbent laminate of

[12] above.

[0021]

[15] In the sulfur-based gas sensor device according to

[14] above, the molded body, the self-adhesive foam sheet, or the self-adhesive laminate is preferably circular in shape.

[0022]

[16] In the sulfur-based gas sensor device according to

[14] or

[15] above, it is preferable that the substrate supporting the molded body, the self-adhesive foam sheet, or the self-adhesive laminate is transparent. [Effects of the Invention]

[0023] According to the present invention, a novel sulfur-based gas sensor material can be provided. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, embodiments of the present invention will be described in detail.

[0025] (Sulfur-based gas sensor material) The sulfur-based gas sensor material of the present invention contains copper ions. The copper ions are a component that imparts deodorizing properties and coloring properties to the sulfur-based gas sensor material by sulfur-based gases. The sulfur-based gas sensor material containing copper ions is not particularly limited as long as it has deodorizing properties and coloring properties by sulfur-based gases.

[0026] Sulfur-based gas sensor materials containing copper ions are particularly excellent in deodorizing sulfur-based gases such as hydrogen sulfide and methyl mercaptan, because sulfur-based gases react with the copper ions to decompose the sulfur-based gases. Furthermore, the sulfur-based gas sensor material containing copper ions is colored yellowish-brown in the presence of a sulfur-based gas by the reaction of the sulfur-based gas with the copper ions to precipitate copper sulfide, making the sulfur-based gas sensor material of the present invention particularly suitable for use as a sulfur-based gas sensor that visualizes the presence and concentration of a sulfur-based gas.

[0027] <Copper-containing oxidized cellulose> The sulfur-based gas sensor material of the present invention preferably contains copper-containing oxidized cellulose, which contains copper in the form of a salt. If the sulfur-based gas sensor contains copper-containing oxidized cellulose, the sulfur-based gas sensor can be endowed with even better deodorizing and coloring properties. Furthermore, when a molded article containing the sulfur-based gas sensor is produced, the molded article can have excellent mechanical strength.

[0028] The copper-containing oxidized cellulose is preferably copper-containing carboxylated cellulose, because copper-containing carboxylated cellulose has excellent dispersibility and can impart desired properties such as deodorizing and coloring properties to the sulfur-based gas sensor material even when used in a small amount.

[0029] Here, the carboxylated cellulose constituting the copper-containing carboxylated cellulose is obtained by oxidizing the primary hydroxyl groups at the 6-positions of the β-glucose units of the starting cellulose to carboxy groups via aldehyde groups. From the viewpoint of sufficiently imparting desired properties to the copper-containing carboxylated cellulose, it is preferred that at least 50 mol%, more preferably at least 70 mol%, and even more preferably at least 90 mol% of the primary hydroxyl groups in the carboxylated cellulose be oxidized to carboxy groups.

[0030] The amount of carboxy groups in the copper-containing carboxylated cellulose can be measured according to the method described in JP-A-2016-141777.

[0031] The amount of copper in the copper-containing oxidized cellulose is not limited as long as it can impart the desired deodorizing and coloring properties to the sulfur-based gas sensor material. For example, in this specification, copper is preferably present in an amount of at least 1 / 3, more preferably at least 1 / 2, of the molar amount of carboxy groups in the copper-containing carboxylated cellulose. The greater the copper content in the copper-containing oxidized cellulose, the more improved the deodorizing and coloring properties of the resulting sulfur-based gas sensor material.

[0032] The metals in the copper-containing oxidized cellulose can be qualitatively and quantitatively analyzed by ICP-AES according to the method described in JP-A-2016-141777, for example.

[0033] The copper-containing oxidized cellulose preferably has the following properties:

[0034] <<Properties of copper-containing oxidized cellulose>> In the present disclosure, the number-average fiber diameter of the copper-containing oxidized cellulose is preferably 100 nm or less, more preferably 50 nm or less, even more preferably 30 nm or less, and particularly preferably 10 nm or less. In this specification, copper-containing oxidized cellulose having a number-average fiber diameter of 100 nm or less is also referred to as copper-containing oxidized cellulose nanofiber. Copper-containing oxidized cellulose nanofibers with a number-average fiber diameter of 100 nm or less have excellent dispersibility, and even when incorporated in small amounts, they can effectively impart desired properties such as deodorizing and coloring properties to sulfur-based gas sensor materials. Furthermore, copper-containing oxidized cellulose nanofibers with a number-average fiber diameter of 100 nm or less have a large specific surface area, so they contain a sufficiently large amount of copper, which can further enhance the deodorizing and coloring properties of sulfur-based gas sensor materials. The number-average fiber diameter of copper-containing oxidized cellulose can be adjusted, for example, by changing the oxidation treatment conditions and the conditions for dispersing (defibrating) the oxidized cellulose after oxidation treatment. Specifically, the number-average fiber diameter can be shortened by extending the dispersion treatment (defibrating treatment) time.

[0035] In the present invention, the "number average fiber diameter" of copper-containing oxidized cellulose can be determined by measuring the fiber diameters of five or more copper-containing oxidized cellulose fibers using an atomic force microscope and calculating the number average of the measured fiber diameters. As the atomic force microscope, for example, a Dimension Fast Scan AFM (Tapping mode, manufactured by BRUKER) can be used.

[0036] Furthermore, the number-average fiber length of the copper-containing oxidized cellulose is preferably 50 nm or more and 2000 nm or less, more preferably 70 nm or more and 1500 nm or less, even 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 when producing a molded body containing a sulfur-based gas sensor material. Furthermore, if the number-average fiber length is 2000 nm or less, the dispersibility of the copper-containing oxidized cellulose can be ensured.

[0037] The number-average fiber length of copper-containing oxidized cellulose 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 oxidized cellulose after oxidation treatment. Specifically, the number-average fiber length can be shortened by extending the dispersion treatment (defibration treatment) time.

[0038] The number-average fiber length of copper-containing oxidized cellulose can be measured by measuring the fiber lengths of five or more copper-containing oxidized cellulose fibers using an atomic force microscope and calculating the average of the obtained measured values. As the atomic force microscope, for example, a DimensionFastScan AFM (Tapping mode, manufactured by BRUKER) can be used.

[0039] Furthermore, the copper-containing oxidized cellulose preferably has an average degree of polymerization (the average number of glucose units contained in a cellulose molecule) of 100 to 2000, more preferably 300 to 1500, even more preferably 500 to 1000, and particularly preferably 500 to 700. If the average degree of polymerization is 100 or more, sufficiently high mechanical strength can be imparted when producing a molded product containing the sulfur-based gas sensor material. If the average degree of polymerization is 2000 or less, the dispersibility of the copper-containing oxidized cellulose can be ensured.

[0040] The average degree of polymerization of copper-containing oxidized cellulose can be adjusted by changing the average degree of polymerization of the natural cellulose used as the raw material, the oxidation treatment conditions, and the conditions for dispersing (defibrating) the oxidized cellulose after oxidation treatment.

[0041] The average degree of polymerization of copper-oxidized cellulose can be determined by, for example, "Isogai, A., Mutoh, N., Onabe, F., Usuda, M., "Viscosity measurements of cellulose / SO 2- The measurement can be carried out in accordance with the method described in "Amine-dimethylsulfoxide solution", Sen'i Gakkaishi, 45, 299-306 (1989)."

[0042] The above-mentioned copper-containing oxidized cellulose containing copper 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. The copper-containing oxidized cellulose containing copper in the form of a salt produced as described above is usually obtained as a dispersion in a dispersion medium such as water.

[0043] (Molded body) The molded article of the present invention is a molded article containing the above-mentioned sulfur-based gas sensor material. The molding method for the molded body is not particularly limited, but examples thereof include extrusion molding, injection molding, foam molding, powder molding, molding using a 3D printer, and application to a substrate. In the present disclosure, the molded article is preferably in a sheet form. The sheet-like molded article includes a sheet, a film, and the like.

[0044] <Self-adhesive foam sheet> The present invention also relates to a self-adsorbing foam sheet (hereinafter also referred to as foam sheet) comprising the above-mentioned sheet-like molded article. The self-adhesive foam sheet is not particularly limited as long as it is made of the above-mentioned sheet-like molded article and has self-adhesive properties. However, it is preferably a sheet having a large number of fine pores, including a polymer and copper-containing oxidized cellulose containing copper in the form of a salt, and optionally further including other additives. Furthermore, it is even more preferable that the self-adhesive foam sheet has open cells formed by interconnecting a plurality of fine pores. If the self-adhesive foam sheet is a sheet having a large number of fine pores as described above, it can be adhered to a smooth substrate such as window glass using the open cells rather than adhesive bonding. Therefore, the self-adhesive foam sheet described above is easier to reattach than conventional adhesive adhesive sheets, and can be suitably used by adhering it to, for example, a support, a wall, a window, etc. Furthermore, if the self-adhesive foam sheet has open cells formed by interconnecting a plurality of fine pores, air pockets are released through the open cells, allowing for neat and easy attachment to the support. The self-adhesive foam sheet can be obtained, for example, by foaming a foam sheet composition containing a polymer and copper-containing oxidized cellulose containing copper in the form of a salt, and optionally further containing a solvent and other additives, and then forming the resulting foam composition into a sheet.

[0045] The self-adsorbing foam sheet of the present invention has deodorizing and coloring properties against sulfur-based gases because it contains a sulfur-based gas sensor material containing copper ions, particularly copper-containing oxidized cellulose containing copper in the form of a salt. Furthermore, the foamed pores allow it to adsorb and deodorize malodorous gases other than sulfur-based gases, such as ammonia.

[0046] [Polymer] The polymer forms the resin matrix in the foam sheet.

[0047] The polymer may be any polymer capable of forming a foamed sheet. Specifically, the polymer may include, but is not limited to, at least one monomer unit selected from the group consisting of a (meth)acrylate monomer unit, an unsaturated carboxylic acid monomer unit, a vinyl cyanide monomer unit, and an alkenyl aromatic monomer unit. Among these, the polymer preferably contains a (meth)acrylate monomer unit, because this provides flexibility to the foamed sheet and enables the foamed sheet to exhibit good adsorption power (self-adhesion power). The polymer may also 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"). The polymer may have a crosslinked structure formed within and / or between molecules using a crosslinking agent or a crosslinkable monomer unit.

[0048] [[(Meth)acrylate monomer units]] The (meth)acrylate monomer unit is a repeating unit derived from a (meth)acrylate monomer. The (meth)acrylate monomer is not particularly limited, but examples thereof include (meth)acrylic acid 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, and n-dodecyl (meth)acrylate; and (meth)acrylic acid alkoxyalkyl ester monomers such as 2-methoxyethyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, and ethoxymethyl (meth)acrylate. The (meth)acrylate monomers may be used alone or in combination of two or more. In the present invention, "(meth)acrylic" means acrylic and / or methacrylic.

[0049] Here, as the (meth)acrylate monomer, from the viewpoint of further increasing the flexibility of the foam sheet and further ensuring the self-adhesive strength of the foam sheet, a (meth)acrylic acid alkyl ester monomer is preferred, and a (meth)acrylic acid alkyl ester monomer in which the carbon number of the alkyl group bonded to a non-carbonyl oxygen atom is 1 to 14 (hereinafter, sometimes abbreviated as "C1-14 (meth)acrylic acid alkyl ester monomer") is more preferred.

[0050] More preferred C1-14 (meth)acrylic acid alkyl ester monomers include, 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, and n-dodecyl methacrylate. Among these, n-butyl acrylate, ethyl acrylate, and 2-ethylhexyl acrylate are preferred from the viewpoints of self-adhesion and cost.

[0051] The proportion of (meth)acrylate monomer units in the polymer is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, particularly preferably 85% by mass or more, and preferably 99% by mass or less, more preferably 95% by mass or less, and even more preferably 92% by mass or less, based on 100% by mass of all repeating units (total monomer units) contained in the polymer. When the proportion of (meth)acrylate monomer units in the polymer is 60% by mass or more, the self-adhesive strength of the foam sheet can be sufficiently ensured. On the other hand, when the proportion of (meth)acrylate monomer units in the polymer is 99% by mass or less, the self-adhesive strength of the foam sheet is not excessively increased. Therefore, the resin residue on the adherend of the self-adhesive laminate including the foam sheet can be reduced.

[0052] [[Unsaturated carboxylic acid monomer unit]] The unsaturated carboxylic acid monomer unit is a repeating unit derived from an unsaturated carboxylic acid monomer. Specific examples of unsaturated carboxylic acid monomers include 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; and α,β-ethylenically unsaturated polycarboxylic acid partial esters such as monomethyl itaconate, monobutyl maleate, and monopropyl fumarate. Furthermore, those having a group that can be converted to a carboxylic acid group by hydrolysis, such as maleic anhydride and itaconic anhydride, can also be used. Among these, itaconic acid, acrylic acid, and methacrylic acid are preferred, and acrylic acid is more preferred, from the viewpoints of reactivity with the crosslinking agent described below, the stability of the polymer latex, and cost. The unsaturated carboxylic acid monomers may be used alone or in combination of two or more.

[0053] The proportion of unsaturated carboxylic acid monomer units 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 even more preferably 2.5% by mass or less, based on 100% by mass of all repeating units (total monomer units) contained in the polymer. Having a proportion of unsaturated carboxylic acid monomer units of 0.1% by mass or more in the polymer allows the crosslinking reaction by the crosslinking agent described below to proceed sufficiently. As a result, the foam sheet can be provided with sufficient strength while suppressing resin residue on the adherend of a self-adhesive laminate including the foam sheet. On the other hand, having a proportion of unsaturated carboxylic acid monomer units of 10% by mass or less in the polymer makes it easy to maintain the viscosity of the polymerization system during polymerization within an appropriate range and also prevents excessive crosslinking of the polymer, which would impair the self-adhesive strength of the foam sheet.

[0054] [[Vinyl cyanide monomer unit]] The vinyl cyanide monomer unit is a repeating unit derived from a vinyl cyanide monomer. Specific examples of vinyl cyanide monomers 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, and examples thereof include acrylonitrile; α-halogenoacrylonitriles such as α-chloroacrylonitrile and α-bromoacrylonitrile; and α-alkylacrylonitriles such as methacrylonitrile and α-ethylacrylonitrile. Among these, acrylonitrile is preferred from the viewpoints of improving the cohesive strength of the foam sheet composition and increasing the breaking strength of the foam sheet. The vinyl cyanide monomers may be used alone or in combination of two or more.

[0055] The proportion of vinyl cyanide monomer units in the polymer is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, and preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, based on 100% by mass of all repeating units (total monomer units) contained in the polymer. When the proportion of vinyl cyanide monomer units in the polymer is 1% by mass or more, sufficient strength can be imparted to the foam sheet while suppressing resin residue on the adherend of the self-adhesive laminate including the foam sheet. On the other hand, when the proportion of vinyl cyanide monomer units in the polymer is 30% by mass or less, sufficient flexibility of the foam sheet can be ensured, and a self-adhesive laminate with good self-adhesive strength can be obtained.

[0056] [[Alkenyl aromatic monomer unit]] The alkenyl aromatic monomer unit is a repeating unit derived from an alkenyl aromatic monomer. Specific examples of alkenyl aromatic monomers include styrene, α-methylstyrene, α-chlorostyrene, vinyltoluene, divinylbenzene, etc. Among these, styrene is preferred from the viewpoints of polymerizability and cost. The alkenyl aromatic monomers may be used alone or in combination of two or more.

[0057] The proportion of alkenyl aromatic monomer units in the polymer is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 1.5% by mass or more, and preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, based on 100% by mass of all repeating units (total monomer units) contained in the polymer. When the proportion of alkenyl aromatic monomer units in the polymer is 0.5% by mass or more, the hydrophobicity of the alkenyl aromatic monomer units can prevent water penetration into the foam sheet, thereby improving the water resistance of the foam sheet. On the other hand, when the proportion of alkenyl aromatic monomer units in the polymer is 20% by mass or less, sufficient flexibility of the foam sheet can be ensured, resulting in a self-adhesive laminate with good self-adhesive strength.

[0058] [[Other monomer units]] The other monomer units are repeating units derived from other monomers copolymerizable with the above-mentioned monomers. Examples of other monomers include conjugated diene monomers, α,β-ethylenically unsaturated polycarboxylic acid complete ester monomers, carboxylic acid unsaturated alcohol ester monomers, olefinic monomers, crosslinkable monomers, etc. These monomers may be used alone or in combination of two or more.

[0059] Specific examples of the conjugated diene monomer include butadiene, isoprene, 1,3-pentadiene, and cyclopentadiene.

[0060] Specific examples of the α,β-ethylenically unsaturated polycarboxylic acid complete ester monomer include dimethyl fumarate, diethyl fumarate, dimethyl maleate, diethyl maleate, and dimethyl itaconate.

[0061] Specific examples of the carboxylic acid unsaturated alcohol ester monomer include vinyl acetate.

[0062] Specific examples of the olefin monomer include ethylene, propylene, butene, and pentene.

[0063] The crosslinkable monomer is a monomer capable of efficiently crosslinking within a polymer molecule and / or between polymer molecules. The crosslinkable monomer is not particularly limited as long as it can crosslink a polymer, and examples thereof include polyfunctional monomers having a plurality of polymerizable unsaturated bonds (excluding the above-mentioned conjugated diene monomers) and monomers having a crosslinkable functional group.

[0064] When a crosslinkable monomer is used, the proportion of the crosslinkable monomer units 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 units in the polymer is within the above range, it becomes easy to maintain the viscosity of the polymerization system during polymerization within an appropriate range, and it also becomes easy to prevent excessive crosslinking of the polymer from impairing the self-adhesiveness of the foam sheet.

[0065] Examples of the polyfunctional monomer include difunctional monomers such as divinylbenzene, ethylene diacrylate, ethylene dimethacrylate, and allyl methacrylate; and trifunctional monomers such as trimethylolpropane trimethacrylate. The polyfunctional monomer preferably has an unsaturated bond at its terminal. The polyfunctional monomers may be used alone or in combination of two or more.

[0066] Examples of the monomer having a crosslinkable functional group include a monomer having a functional group such as an organic acid group other than a carboxy group, a hydroxyl group, an amino group, an amide group, a mercapto group, or an epoxy group.

[0067] The monomer having an organic acid group is not particularly limited, but typical examples 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.

[0068] 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 acrylamido-2-methylpropane sulfonic acid, and salts thereof.

[0069] When a monomer having an organic acid group is used, the content of the monomer units derived from the monomer having an organic acid group in the polymer is preferably 0.1% by mass to 10% by mass, more preferably 0.5% by mass to 5% by mass. When the content of the monomer units derived from the monomer having an organic acid group in the polymer is within the above range, it becomes easy to maintain the viscosity of the polymerization system within an appropriate range during polymerization, and it becomes easy to prevent excessive crosslinking of the polymer from impairing the self-adhesiveness of the foam sheet.

[0070] The monomer unit having an organic acid group is preferably introduced into the polymer by polymerization of a monomer having an organic acid group, because this is simple. However, the organic acid group may be introduced after the polymer is produced by a known polymer reaction.

[0071] When a monomer having a functional group other than an organic acid group (hydroxyl group, amino group, amide group, epoxy group) is used, the content of monomer units derived from the monomer having the functional group other than an organic acid group in the polymer is preferably 10% by mass or less. When the content of monomer units derived from the monomer having the functional group other than an organic acid group in the polymer is 10% by mass or less, it becomes easy to maintain the viscosity of the polymerization system within an appropriate range during polymerization and also to prevent excessive crosslinking of the polymer from impairing the self-adhesiveness of the foam sheet.

[0072] In order to sufficiently suppress the generation of formaldehyde during the formation of 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.

[0073] The polymer preferably has the following properties:

[0074] [Polymer properties] Specifically, the glass transition temperature of the polymer is preferably −10°C or lower, more preferably −13°C or lower, even more preferably −17°C or lower, and particularly preferably −20°C or lower. When the glass transition temperature of the polymer is −10°C or lower, the self-adhesive strength of the foam sheet is sufficiently ensured, while the self-adhesive laminate including the foam sheet can be well adhered to the adherend. This prevents moisture from penetrating between the adherend and the foam sheet. This improves the water resistance of the self-adhesive laminate including the foam sheet. The lower limit of the glass transition temperature of the polymer is not particularly limited, but is preferably −40° C. or higher from the viewpoint of sufficiently suppressing resin residue on the adherend of the self-adhesive laminate including the foam sheet. 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 K 7121. As the differential scanning calorimeter, for example, a DSC7000X (manufactured by Hitachi High-Tech Science Corporation) can be used.

[0075] The gel fraction of the polymer is preferably 95% by mass or less, and more preferably 93% by mass or less. If the gel fraction is 95% by mass or less, a foamed sheet having appropriate self-adhesive strength and excellent smoothness can be obtained. The lower limit of the gel fraction of the polymer is not particularly limited, but can be, for example, 50% by mass or more, or 70% by mass or more. The gel fraction of a polymer can be measured, for example, by the following method. First, the polymer is applied to a 50 μm-thick polyethylene terephthalate (PET) film using a 250 μm applicator and dried at room temperature for 24 hours to obtain a resin film. A predetermined amount (X) (approximately 500 mg) of this film is precisely weighed and immersed in 100 mL of ethyl acetate at room temperature for 3 days. The insoluble matter is then filtered through a 200-mesh wire screen, air-dried at room temperature for 15 hours, dried at 100°C for 2 hours, and cooled at room temperature. The mass (Y) of the sample is then measured. The gel fraction is then calculated by substituting X and Y into the following equation: Gel fraction (%) = (Y) / (X) × 100

[0076] [Copper-containing oxidized cellulose] The copper-containing oxidized cellulose contained in the foamed sheet, which contains copper in the form of a salt, can be the copper-containing oxidized cellulose described in the section "Sulfur-based gas sensor material." The copper-containing oxidized cellulose is preferably copper-containing carboxylated cellulose, and is preferably copper-containing oxidized cellulose nanofiber. The amount of carboxy groups and copper contained in the copper-containing oxidized cellulose, as well as various properties (number-average fiber diameter, number-average fiber length, average degree of polymerization, etc.), are preferably within the ranges described above in the section "Properties of copper-containing oxidized cellulose."

[0077] From the viewpoint of achieving both colorability and deodorizing properties in a foam sheet and the adsorption properties of the foam sheet, the content of the copper-containing oxidized cellulose in the foam sheet is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, and even more preferably 0.4 parts by mass or more, and is preferably 1.2 parts by mass or less, more preferably 1.1 parts by mass or less, even more preferably 1.0 part by mass or less, and even more preferably 0.9 parts by mass or less, per 100 parts by mass of the polymer.

[0078] [Other additives] The foam sheet can optionally contain various additives to improve processability during the foam sheet production process and to improve the performance of the foam sheet. Examples of such additives include crosslinkers, foam stabilizers such as higher fatty acid salts and surfactants, foaming aids, thickeners, fillers, preservatives, mildew inhibitors, gelling agents, flame retardants, antioxidants, antioxidants, pigments, dyes, tackifiers, conductive compounds, water-resistant agents, and oil-resistant agents. Specific examples of the other additives mentioned above are not particularly limited, and known additives, such as those described in International Publication No. 2016 / 147679, can be used.

[0079] Here, the crosslinking agent is not particularly limited as long as it can form a crosslinked structure with the above-mentioned polymer (especially the unsaturated carboxylic acid monomer unit of the above-mentioned 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, and diphenylmethane triisocyanate; metal salt-based crosslinking agents; metal chelate-based crosslinking agents; and peroxide-based crosslinking agents. Among these, epoxy-based crosslinking agents are preferably used, and compounds having two or more epoxy groups in one molecule are more preferably used. Furthermore, fatty acid polyglycidyl ether, glycerol polyglycidyl ether, and ethylene glycol diglycidyl ether are preferred as epoxy-based crosslinking agents.

[0080] The epoxy crosslinking agent may be synthesized by a known method, or a commercially available product such as "Rikabond (registered trademark)" manufactured by Japan Coating Resins Co., Ltd. may be used. Epoxy-based crosslinking agents form crosslinked structures within or between polymer molecules by reacting their epoxy groups with functional groups in the polymer (e.g., carboxylic acid groups derived from unsaturated carboxylic acid monomer units). The use of epoxy-based crosslinking agents allows for the formation of foamed sheets with adequate self-adhesive strength and excellent strength. Therefore, the use of epoxy-based crosslinking agents as crosslinking agents can prevent resin residue from remaining on the substrate of the foamed sheet.

[0081] In the present invention, it is preferable not to use a crosslinking agent that generates formaldehyde, such as a melamine-formaldehyde resin, a urea-formaldehyde resin, or a phenol-formaldehyde resin.

[0082] The amount of crosslinking agent is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 3 parts by mass or more, and preferably 20 parts by mass or less, and more preferably 10 parts by mass or less, per 100 parts by mass of the polymer. By using a crosslinking agent in an amount within the above-described range, a foam sheet can be obtained that maintains appropriate strength and elasticity. Therefore, when pressure applied to the foam sheet is released, the collapsed foam cells in the foam sheet can recover to their original shape. This ensures the self-adhesive strength of the foam sheet and sufficiently prevents resin residue from remaining on the adherend.

[0083] As the foam stabilizer, fatty acid ammonium salts such as ammonium stearate; sulfonic acid type anionic surfactants such as alkyl sulfosuccinates; quaternary alkyl ammonium chlorides; alkyl betaine amphoterates; and fatty acid alkanolamines can be used.

[0084] Further, 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.

[0085] <<Properties of foam sheet>> The self-adhesive foam sheet preferably has the following properties:

[0086] The density of the foam sheet is not particularly limited, but is preferably 0.3 g / cm 3 It is preferable that the concentration is 0.4 g / cm or more. 3 More preferably, it is 1.0 g / cm or more. 3 It is preferable that the concentration is 0.7 g / cm or less. 3 More preferably, it is 0.6 g / cm or less. 3 It is more preferable that the density of the foamed sheet is 0.3 g / cm or less. 3 If the density of the foamed sheet is 1.0 g / cm or more, the strength of the foamed sheet can be ensured. 3 If the thickness is less than this, the foam sheet will have a sufficiently large number of voids, and the surface area in contact with the outside air will be sufficiently large, thereby ensuring deodorizing and coloring properties and sufficiently enhancing air release properties (the ability to easily remove air pockets remaining between the foam sheet and the adherend).

[0087] The thickness of the foam sheet is preferably 30 μm or more, more preferably 50 μm or more, and even more preferably 100 μm or more, and is preferably 3 mm or less, more preferably 1 mm or less, even 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 foam sheet has a sufficiently large number of voids, and the surface area in contact with the outside air is sufficiently large, thereby improving the deodorizing and coloring properties of the foam sheet and ensuring sufficient mechanical strength. On the other hand, if the thickness of the foam sheet is 3 mm or less, a self-adhesive laminate with excellent repetitive adhesion (reworkability) can be obtained.

[0088] The foam sheet preferably contains open cells formed by interconnecting a plurality of cells. When the foam sheet contains such open cells, air trapped between the foam sheet and the adherend can be easily removed to the outside of the foam sheet through the open cells, further improving the air release properties of the foam sheet and allowing the foam sheet to be attached to the adherend cleanly and easily. Furthermore, when the foam sheet contains such open cells, the contact area with the outside air increases, enabling more odorous components to be deodorized, and the sensitivity to discoloration by sulfur-based gases is also improved, thereby further improving the deodorizing and coloring properties of the foam sheet. From the viewpoint of further improving the air release properties, deodorizing properties, and coloring properties, the open cells in the foam sheet preferably include open cells extending in the planar direction of the foam sheet. The open cells in the foamed sheet can usually be confirmed by observing the cross section of the foamed sheet using, for example, a laser microscope, a digital microscope, or a scanning electron microscope. The open cells can also be confirmed in the foamed composition obtained by foaming the foam sheet composition by, for example, placing the foamed composition in a transparent container and observing it with an X-ray CT.

[0089] The properties of the foamed sheet (density, thickness, open cells, hardness, etc.) can be adjusted by, for example, changing the mixing ratio of bubbles, the composition of the foamed sheet composition, the solid content concentration, the viscosity, and the drying and crosslinking conditions in the foamed sheet manufacturing method described below.

[0090] <Self-adhesive laminate> The self-adhesive laminate of the present invention comprises a substrate and the self-adhesive foam sheet of the present invention, wherein the foam sheet forms a foam layer, and the substrate forms a support layer that supports the foam layer. The foam sheet may be formed directly on the substrate or may be formed on the substrate via any layer, but from the viewpoint of improving the deodorizing properties and colorability of the self-adhesive laminate, it is preferable that the foam sheet be formed directly on the substrate. Furthermore, the self-adhesive laminate of the present invention may have foam sheets on both sides of the substrate.

[0091] The substrate for the laminate sheet of the present invention may be a paper substrate, synthetic paper, plastic substrate, fiber substrate, metal substrate, glass substrate, etc. The thickness of the substrate is not particularly limited, but may be, for example, 10 μm or more and 500 μm or less.

[0092] Examples of the paper substrate include fine paper, art paper, coated paper, kraft paper, and these paper substrates laminated with a thermoplastic resin such as polyethylene.

[0093] The synthetic paper is not particularly limited, but is a paper-like surface layer made by combining a thermoplastic resin and an inorganic filler.

[0094] Examples of plastic substrates include polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polystyrene resins; polyvinyl chloride resins; acrylic resins; polycarbonate resins; polyamide resins; fluorine-based resins such as polytetrafluoroethylene; polyolefin resins such as polyethylene and polypropylene; cyclic polyolefin resins, and sheet-like substrates made of mixtures or laminates of these resins.

[0095] Examples of fiber substrates include natural fibers such as cotton and silk; polyamide synthetic fibers; polyester synthetic fibers; polypropylene synthetic fibers; polyvinyl chloride synthetic fibers; polyvinyl alcohol synthetic fibers; semi-synthetic fibers such as acetate; regenerated artificial fibers such as rayon; and sheet-like substrates made of mixtures or laminates of these fibers.

[0096] The metal substrate is not particularly limited, and examples thereof include sheet-like substrates made of metals such as iron, copper, aluminum, gold, platinum, and silver, as well as alloys or laminates of these metals.

[0097] The glass substrate is not particularly limited, and examples thereof include sheet-like substrates made of soda lime glass, borosilicate glass, alkali-free glass, quartz glass, and the like.

[0098] (Method for manufacturing self-adhesive laminate) The method for producing a self-adhesive laminate of the present invention includes a step of foaming a composition for a self-adhesive foam sheet, which comprises a polymer and copper-containing oxidized cellulose containing copper in the form of a salt, to obtain a foam composition (foaming step), and a step of forming the foam composition into a sheet on a substrate (sheet-forming step). The laminate obtained through the above-described steps is not particularly limited, but for example, a separator film may be attached to the self-adhesive surface (i.e., the surface on the foamed sheet side), and then the laminate may be wound up by a winder and cut to a convenient size by press cutting, slitter, or the like.

[0099] <Foaming process> In the foaming step, a composition for a self-adsorbing foam sheet (hereinafter, sometimes referred to as a "composition for a foam sheet") is foamed to obtain a foam composition.

[0100] The foam sheet composition includes a polymer and copper-containing oxidized cellulose containing copper in the form of a salt, and optionally further includes a solvent and other additives. The foam sheet composition can be the foam sheet composition described in the "Self-adsorbent foam sheet" section. The polymer, copper-containing oxidized cellulose, and other additives can be those described in the "Self-adsorbent foam sheet" and "Sulfur-based gas sensor material" sections, respectively.

[0101] The polymerization method for obtaining the polymer used in the foam sheet composition 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 limitations on the types and amounts of polymerization initiators, emulsifiers, dispersants, etc. used in the polymerization. There are also no particular limitations on the methods for adding monomers, polymerization initiators, emulsifiers, dispersants, etc. during polymerization. There are also no particular limitations on the polymerization temperature, pressure, stirring conditions, etc.

[0102] Although the polymer can be used in a solid state, it is preferable to use it in the form of a latex containing the polymer (polymer latex), such as a latex obtained by emulsion polymerization or a latex obtained by post-emulsifying the polymer, because this allows for easy mixing of the polymer with copper-containing oxidized cellulose containing copper in the form of a salt, an optional solvent, and other additives, and is also convenient for foaming the resulting foam sheet composition. Here, when the polymer is used in the form of a polymer latex for preparing a foam sheet composition as described above, the solids concentration of the polymer latex is preferably 40% by mass or more, more preferably 45% by mass or more, even more preferably 50% by mass or more, and particularly preferably 52% by mass or more, from the viewpoint of maintaining the density of the resulting foam sheet, and is preferably 70% by mass or less, and more preferably 60% by mass or less.

[0103] Furthermore, copper-containing oxidized cellulose can be used in the preparation of a foam sheet composition in the form of a dispersion in a dispersion medium such as water, in which the copper-containing oxidized cellulose is highly dispersed, preferably to a level where the number average fiber diameter is 100 nm or less, more preferably 2 to 50 nm, even more preferably 2 to 10 nm, still more preferably 2 to 5 nm, and particularly preferably 3 to 4 nm. Therefore, by using this dispersion, it is possible to obtain a composition for foam sheets that can produce foam sheets with excellent deodorizing and coloring effects. Specifically, by adding the dispersion containing copper-containing cellulose as is to the above-mentioned polymer or polymer latex and stirring the resulting mixture, it is possible to obtain a composition for foam sheets in which the copper-containing oxidized cellulose is sufficiently dispersed. Furthermore, it is preferable to add the dispersion containing copper-containing cellulose little by little using a pipette or the like to the stirred polymer or polymer latex, as this prevents aggregation of the copper-containing oxidized cellulose.

[0104] Here, the solids concentration of the copper-containing oxidized cellulose in the dispersion is preferably 0.05% by mass or more and 2.0% by mass or less. A solids concentration of 0.05% by mass or more prevents an increase in the content of the dispersion medium, such as water, in the resulting foam sheet composition, which would otherwise reduce the viscosity of the composition, allowing for the formation of a smoother, more uniform sheet. On the other hand, a solids concentration of 2.0% or less prevents the dispersion from becoming pseudo-gelled like a jelly, further improving the dispersibility of the copper-containing oxidized cellulose in the resulting foam sheet composition. When a solid copper-containing oxidized cellulose is used, the dispersion liquid may be dried by a known method.

[0105] The solvent that the foam sheet composition may optionally contain is not particularly limited, but is preferably water. When water is used as the solvent, the water contained in the foam sheet composition may be, for example, water derived from a polymer latex and / or water derived from an aqueous dispersion of copper-containing oxidized cellulose containing copper in the form of a salt. The water contained in the foam sheet composition may also be water derived from other additives.

[0106] When the foam sheet composition contains a solvent (i.e., in the form of a dispersion in which copper-containing oxidized cellulose is dispersed), the viscosity of the foam sheet composition is preferably 800 mPa·s to 10,000 mPa·s, more preferably 900 mPa·s to 8,000 mPa·s, even more preferably 1,000 mPa·s to 7,500 mPa·s, and particularly preferably 1,500 mPa·s to 3,000 mPa·s. A foam sheet composition having a viscosity of 800 mPa·s or more can prevent dripping and difficulty in controlling the thickness when the foam sheet is formed by applying the foam composition formed from the foam sheet composition to a substrate. On the other hand, a foam sheet composition having a viscosity of 10,000 mPa·s or less can prevent difficulty in controlling the expansion ratio by mechanical foaming when forming the foam sheet. The viscosity of the foam sheet composition can be measured at 23°C using a Brookfield viscometer.

[0107] The pH of the foam sheet composition is preferably 5 or higher, more preferably 7 or higher, and even more preferably 8 or higher, and is preferably 10 or lower, more preferably 9.7 or lower, and even more preferably 9.5 or lower. A pH of 5 or higher effectively prevents cellulose precipitation and aggregation, which occur when copper is removed from copper-containing oxidized cellulose (containing copper in the form of a salt) to form a carboxylic acid, as well as sedimentation due to aggregation of the removed metal ions. On the other hand, a pH of 10 or lower effectively prevents a decrease in the strength of the foam sheet, which is caused by the crosslinking reaction being slowed down when a crosslinking agent is used. The pH of the composition for a foam sheet can be measured at a temperature of 23°C using a pH meter.

[0108] The foam sheet composition can be produced by mixing the polymer and copper-containing oxidized cellulose containing copper in the form of a salt with a solvent and other additives, which are used as desired, by any method.

[0109] For example, when a polymer latex is used in preparing a foam sheet composition, copper-containing oxidized cellulose containing copper in the form of a salt and other optional additives may be added to the polymer latex and mixed by a known method.

[0110] Furthermore, for example, when a dispersion of copper-containing oxidized cellulose containing copper in the form of a salt is used in preparing a foam sheet composition, a solid polymer or polymer latex and other optional additives may be added to the dispersion and mixed by a known method.

[0111] Furthermore, for example, when a solvent is not used in preparing a foam sheet composition, a solid polymer, a copper-containing oxidized cellulose containing copper in the form of a salt, and other solid additives that are optionally used may be mixed by a known method, for example, using a known roll, Henschel mixer, kneader, or the like.

[0112] From the viewpoint of favorably dispersing copper-containing oxidized cellulose containing copper in the form of a salt in a foam sheet composition, it is preferable to add a dispersion (e.g., an aqueous dispersion) of copper-containing oxidized cellulose containing copper in the form of a salt to a polymer latex under stirring to obtain a mixed solution, and then optionally add other additives to the mixed solution and further mix by a known method. It is preferable that other additives that increase the viscosity of the system, such as crosslinking agents and thickeners, are added as late as possible to maintain a uniform composition in the system.

[0113] Mechanical foaming is typically used to foam the foam sheet composition. The foaming ratio can be adjusted as needed, but is typically between 1.2 and 5 times, and preferably between 1.5 and 4 times. The mechanical foaming method is not particularly limited, but can be performed by mixing a certain amount of air into the dispersion of the foam sheet composition and stirring it continuously or batchwise using an oak mixer, whipper, or the like. The foamed dispersion thus obtained is creamy. The formation of pores by the mechanical foaming ultimately results in a foamed sheet with excellent air release properties. An expansion ratio of 1.2 times or more can prevent a decrease in air release properties, while an expansion ratio of 5 times or less can prevent a decrease in the strength of the foamed sheet. The expansion ratio was determined by the following method. The weight per 210 mL of a foamed sheet composition that had been defoamed using a vacuum planetary mixer (Awatori Rentaro ARV-310) was designated A0, and the weight per 210 mL of a foamed composition obtained by foaming the foamed sheet composition was designated A1. The expansion ratio was determined by the formula: expansion ratio = A0 / A1.

[0114] <Sheeting process> The method for forming the foam composition into a sheet on a substrate is not particularly limited. Suitable methods include, for example, a method of applying the foam composition to a substrate in a sheet form. The method for applying the foam composition to a substrate or the like may include, for example, a method using a commonly known coating device such as a roll coater, a reverse roll coater, a screen coater, a doctor knife coater, or a comma knife coater. The substrate may be any of those described above in the section on "self-adhesive laminate." If a film or the like with a release-treated surface is used, the sheet can be isolated.

[0115] The solidification of the foam composition, which is performed as needed, is carried out, for example, by crosslinking the polymer of the foam composition formed into a sheet. The method for crosslinking the polymer is not particularly limited, but a method of heating and drying the foam composition is preferred. The heat drying method is not particularly limited as long as it is a method that can dry the foam composition on the substrate or the like and crosslink the polymer, and known drying ovens (e.g., hot air circulating ovens, hot oil circulating hot air chambers, far-infrared heater chambers) can be used. The drying temperature can be, for example, 60°C or higher and 180°C or lower. It is also preferable to perform multi-stage drying, such as drying from the inside at a low temperature in the early stages of drying and then sufficiently drying at a higher temperature in the later stages of drying, rather than performing drying at a constant temperature.

[0116] In this way, a self-adhesive laminate is obtained which comprises a self-adhesive foam sheet formed by solidifying a sheet-like foam composition on a substrate or the like.

[0117] (Sulfur gas sensor device) The sulfur-based gas sensor device of the present invention includes the molded article, self-adsorbing foam sheet, or self-adsorbing laminate of the present invention. The sulfur-based gas sensor device is not particularly limited as long as the molded article, self-adsorbing foam sheet, or self-adsorbing laminate of the present invention (hereinafter also referred to as "molded article, etc.") can exhibit deodorizing properties and coloration by sulfur-based gases, and the presence of sulfur-based gases can be visualized from the coloring of the molded article, etc. The sulfur-based gas sensor device may, for example, be one in which the molded article, etc. of the present invention is sandwiched between a housing.

[0118] The shape of the molded body or the like provided in the sulfur-based gas sensor device is not particularly limited, but a circular sheet shape is preferable. If the molded body or the like is in the shape of a circular sheet, the coloring of the molded body or the like due to the sulfur-based gas progresses from the periphery of the circle toward the center, making it easy to visually recognize the presence and concentration of the sulfur-based gas. In addition, the remaining time until the molded body or the like is consumed by reaction with the sulfur-based gas (i.e., until the entire molded body or the like is completely colored) can be easily estimated.

[0119] In the sulfur-based gas sensor device, the substrate supporting the molded body etc. is preferably transparent, which further improves the visibility of the coloring of the molded body etc. As the substrate, for example, those mentioned in the section "Self-adhesive laminate" can be used. From the viewpoint of transparency, plastic substrates and glass substrates are particularly preferred.

[0120] In addition, in a sulfur-based gas sensor device, the substrate supporting the molded body or the like preferably has high gas permeability. If the substrate has high gas permeability, the amount of outside air that comes into contact with the molded body or the like contained in the sulfur-based gas sensor device increases, allowing more odorous components to be deodorized and improving the coloring sensitivity of the molded body or the like to sulfur-based gases. From the above perspective, it is preferable to use a fibrous substrate such as a woven fabric, a nonwoven fabric, or paper. [Example]

[0121] The present invention will be specifically described below based on examples, but the present invention is not limited to these examples. In the following description, "%" and "parts" representing amounts are based on mass unless otherwise specified. Furthermore, in a polymer produced by copolymerizing multiple types of monomers, the proportion of a monomer unit formed by polymerizing a certain monomer in the polymer usually coincides with the ratio (feed ratio) of the certain monomer to all the monomers used in the polymerization of the polymer, unless otherwise specified. In the examples and comparative examples, various measurements and evaluations were carried out by the following methods.

[0122] (Measurement and Evaluation) <Viscosity of the foam sheet composition> The viscosity of the foam sheet composition was measured at 23°C using a Brookfield viscometer (manufactured by Rion Co., Ltd., "VISCOTESTER VT-06").

[0123] <pH of foam sheet composition> The pH of the foam sheet composition was measured at 23°C using a pH meter (pH METER F-52 manufactured by HORIBA).

[0124] <Thickness and density of foam layer> The laminate sheet was cut into eight 50mm x 50mm squares, and the mass (balance: A&D BM-252) and thickness (thickness meter: Ozaki Seisakusho PEACOK MODEL H) of each were measured and the average value was calculated. Similarly, eight 50mm x 50mm squares of the substrate (synthetic paper, film, etc.) were cut into individual pieces and the mass and thickness of each were measured and the average value was calculated. The mass of the foam layer was calculated by subtracting the average mass of the substrate from the average mass of the laminate sheet. The thickness of the foam layer was also calculated by subtracting the average thickness of the substrate from the average thickness of the laminate sheet. The density of the foam layer was calculated by dividing this value by the volume (50mm x 50mm x average thickness).

[0125] <Evaluation of deodorizing properties> After preparing the laminated sheet, it was cut into a circle with a radius of 50 mm x thickness for round shapes, or a square shape with a dimension of 100 mm x 100 mm x thickness. The foam layer side of the cut sample was attached to a 120 mm x 120 mm x 1 mm soda glass sheet. The sample was placed in a sampling pack (GL Sciences SMART BAG PA AA-5) and the top was heat-sealed. The sampling pack was degassed using a vacuum pump, and gases of the types and initial concentrations listed in Table 1 were sealed into the sampling pack. After a predetermined time, the gas concentration (ppm by mass) inside the pack was measured using a gas detector tube (Gastec Gas Detector Tube). The shorter the gas concentration, the better the deodorizing effect.

[0126] <Coloring evaluation> [Coloring evaluation] For the samples attached to the soda glass, the color change of the laminated sheet as viewed from the soda glass side and the substrate side was visually observed before and after the deodorizing property evaluation test, and evaluated as follows. A: It can be seen that the color is clearly yellow-brown compared to before the test. B: A slight color change can be seen compared to before the test. C: No coloring was observed, just like before the test.

[0127] [Coloring uniformity evaluation] In addition, during the above coloring evaluation, the uniformity of the coloring of the laminated sheet was also visually observed and evaluated as follows. Good: Color is evenly distributed in concentric circles. Poor: Color is not uniform.

[0128] (Production Example 1) <Preparation of polymer latex> A monomer mixture consisting of 64 parts of ethyl acrylate, 12 parts of 2-ethylhexyl acrylate, 12 parts of n-butyl acrylate, 9 parts of acrylonitrile, 2 parts of styrene, and 1 part of acrylic acid, and 0.4 parts of sodium polyoxyethylene alkyl sulfate (Latemul E-118B, manufactured by Kao Corporation) were mixed with 27.0 parts of deionized water 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 of deionized water and 0.2 parts 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 of ammonium persulfate dissolved in 5.7 parts 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 cooled to terminate the reaction, obtaining a reaction mixture. The polymerization conversion rate at this time was almost 100% (98% or more). The obtained reaction mixture was adjusted to pH 5.0 with 5% aqueous ammonia, and after adding 2.5 parts of polyoxyethylene lauryl ether (manufactured by Kao Corporation: Emulgen 120), concentration was carried out to obtain a polymer latex having a solid content concentration of 58% by mass, a glass transition temperature of -20°C, and a gel fraction of 80% by mass.

[0129] <Preparation of 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 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. Distilled water was then added to the undried TEMPO-catalyzed pulp to prepare an aqueous dispersion with a solids concentration of 0.1% by mass. The aqueous dispersion was then defibrated using a homogenizer (Microtec Nithion, Hiscotron) at 7.5 × 1000 rpm for 2 minutes, and then using an ultrasonic homogenizer (Nissei, Ultrasonic Generator) with a V-LEVEL 4, TIP26D, for 4 minutes while cooling the container with ice. This resulted in an aqueous dispersion containing TEMPO-carboxylated cellulose nanofibers as TEMPO-oxidized cellulose nanofibers. The undefibrated components were then removed from the aqueous dispersion by centrifugation using a SAKUMA centrifuge (M201-1VD, angle rotor 50F-8AL) at 12,000 G (120 × 100 rpm / g) for 10 minutes at 12°C, yielding a clear aqueous dispersion of TEMPO-carboxylated cellulose nanofibers with a solids concentration of 0.1%. The TEMPO-carboxylated cellulose nanofibers contained sodium derived from the co-oxidant in the form of a salt.

[0130] <Preparation of hydrogen-substituted TEMPO-oxidized cellulose nanofiber aqueous dispersion> To 100 mL of the TEMPO-carboxylated cellulose nanofiber aqueous dispersion, 1 mL of 1 M hydrochloric acid was added under stirring to adjust the pH to 1. Stirring was then continued for 60 minutes (hydrogen substitution step). The TEMPO-carboxylated cellulose nanofibers that had been gelled by the addition of hydrochloric acid were then collected by centrifugation (12,000 G), and the collected TEMPO-carboxylated cellulose nanofibers were washed successively with 1 M hydrochloric acid and a large amount of distilled water (first washing step). Next, 100 mL of distilled water was added to obtain a 0.1% aqueous dispersion of hydrogen-substituted TEMPO-carboxylated cellulose nanofibers (first dispersion step). Measurement of the surface carboxyl groups of the hydrogen-substituted TEMPO-carboxylated cellulose nanofibers by FT-IR (JASCO Corporation, FT / IR-6100) according to Biomacromolecules (2011, Vol. 12, pp. 518-522) revealed that more than 90 mol % of the groups were substituted with carboxylic acid groups.

[0131] <Preparation of copper-containing TEMPO-oxidized cellulose nanofiber aqueous dispersion> 50 g of the 0.1% hydrogen-substituted TEMPO-carboxylated cellulose nanofiber aqueous dispersion was stirred, and 18 g of a 0.1% copper (II) acetate solution was added. Stirring was continued for 3 hours at room temperature (metal substitution step). The carboxylated cellulose nanofibers gelled with the addition of the copper (II) acetate solution were then collected by centrifugation (12,000 G (120 × 100 rpm / g), 10 minutes, 12°C) using a centrifuge (SAKUMA, M201-1VD, angle rotor 50F-8AL) and washed with the 0.1% copper (II) acetate solution. The collected cellulose nanofibers were then washed with a large amount of distilled water (washing step). Next, 50 mL of distilled water was added, and the mixture was sonicated (for 2 minutes) using an ultrasonic homogenizer (Nissei, Ultrasonic Generator) with V-LEVEL 4 and TIP26D while the container was cooled with ice to disperse the copper-substituted TEMPO-carboxylated cellulose nanofibers. The copper-substituted TEMPO-carboxylated cellulose nanofiber aqueous dispersion was then centrifuged (12,000 G (120 × 100 rpm / g), 10 minutes, 12°C) using a centrifuge (SAKUMA, M201-1VD, angle rotor 50F-8AL) at 12,000 G (120 × 100 rpm / g), 10 minutes, 12°C. This resulted in an aqueous dispersion of copper-containing TEMPO-oxidized cellulose nanofibers (hereinafter simply referred to as "TOCN-Cu") with a solids concentration of 0.1%. This aqueous dispersion was then concentrated using an evaporator to obtain an aqueous TOCN-Cu dispersion with a solids concentration of 1.0%.

[0132] <Preparation of Foaming Composition> 170 g of the polymer latex (solid concentration: 58%) was weighed into a 500 ml disposable cup and stirred (1750 rpm) with a mixer (ROBOMICS manufactured by Tokushu Kika Kogyo Co., Ltd.) 94.1 g of the TOCN-Cu aqueous dispersion (solid concentration: 1.0%) (TOCN-Cu content: 1 part by mass per 100 parts by mass of polymer) was gradually added in small amounts to the stirred polymer latex, and stirring was continued for 30 minutes after the addition. Then, while stirring the resulting mixture, 6.75 g of ammonium stearate (30% concentration, manufactured by San Nopco Co., Ltd., Nopco DC-100A) as a foam stabilizer, 5.14 g of fatty acid polyglycidyl ether (100% concentration, manufactured by Japan Coating Resins Co., Ltd., Rikabond EX-8) as an epoxy crosslinker (5.21 parts by mass of epoxy crosslinker per 100 parts by mass of polymer), and 5.21 g of sodium polyacrylate (15% concentration, manufactured by Toagosei Co., Ltd.) as a thickener were added to the mixture in this order, followed by stirring for 30 minutes to obtain a foam sheet composition. The foam sheet composition had an active ingredient concentration of 38%, a viscosity of 1,800 mPa·s, and a pH of 8.2. The foam sheet composition was foamed 2.0 times using a whisk (a hand mixer THM272 manufactured by Tescom Co., Ltd.) to a density of 0.49 g / cm. 3 A foaming composition (foaming liquid) of the formula was obtained.

[0133] (Production Example 2) In the "Preparation of Foaming Composition" step of Production Example 1, 200 g of the polymer latex (solid content concentration: 58%) was weighed into a 500 ml disposable cup and stirred (1750 rpm) with a mixer (ROBOMICS, manufactured by Tokushu Kika Kogyo Co., Ltd.). 65.3 g of the TOCN-Cu aqueous dispersion (solid content concentration: 1.0%) (TOCN-Cu content: 0.5 parts by mass relative to 100 parts by mass of polymer) was gradually added in small amounts to the stirred polymer latex, and stirring was continued for 30 minutes after the addition. Subsequently, while stirring the resulting mixture, 8.13 g of ammonium stearate (30% concentration, manufactured by San Nopco Co., Ltd., Nopco DC-100A), 6.02 g of a fatty acid polyglycidyl ether (100% concentration, manufactured by Japan Coating Resins Co., Ltd., Rikabond EX-8), and 6.29 g of a thickener sodium polyacrylate (15% concentration, manufactured by Toagosei Co., Ltd.), were added in this order, followed by stirring for 30 minutes. The process was repeated as in Production Example 1, yielding a foam sheet composition. The foam sheet composition had an active ingredient concentration of 44%, a viscosity of 1,900 mPa·s, and a pH of 8.6. The foam sheet composition was foamed 2.0 times using a whisk (THM272 hand mixer, manufactured by Tescom Co., Ltd.), resulting in a density of 0.49 g / cm. 3 A foaming composition (foaming liquid) of the formula was obtained.

[0134] (Production Example 3) In the "Preparation of Foaming Composition" step of Production Example 1, 200 g of the polymer latex (solid content concentration: 58%) was weighed into a 500 ml disposable cup and stirred (1750 rpm) with a mixer (ROBOMICS, manufactured by Tokushu Kika Kogyo Co., Ltd.). 65.3 g of the TOCN-Cu aqueous dispersion (solid content concentration: 1.0%) (TOCN-Cu content: 0.5 parts by mass relative to 100 parts by mass of polymer) was gradually added in small amounts to the stirred polymer latex, and stirring was continued for 30 minutes after the addition. Subsequently, while stirring the resulting mixture, 8.13 g of ammonium stearate (30% concentration, manufactured by San Nopco Co., Ltd., Nopco DC-100A), 6.02 g of a fatty acid polyglycidyl ether (100% concentration, manufactured by Japan Coating Resins Co., Ltd., Rikabond EX-8) as an epoxy crosslinker (5.18 parts by mass of epoxy crosslinker per 100 parts by mass of polymer), and 6.29 g of sodium polyacrylate (15% concentration, manufactured by Toagosei Co., Ltd.) as a thickener were added in this order, followed by stirring for 30 minutes. The process was carried out in the same manner as in Production Example 1, yielding a foamable sheet composition. The foamable sheet composition had an active ingredient concentration of 44%, a viscosity of 1,900 mPa·s, and a pH of 8.6. The foamable sheet composition was degassed using a vacuum planetary mixer (Awatori Rentaro ARV-310) to a density of 1.00 g / cm. 3 A foaming composition (foaming liquid) of the formula was obtained.

[0135] (Production Example 4) The aqueous dispersion of TEMPO-carboxylated cellulose nanofibers containing sodium derived from the co-oxidant in the form of a salt, obtained in the step "Preparation of aqueous dispersion of TEMPO-oxidized cellulose nanofibers" in Production Example 1, was concentrated using an evaporator to obtain an aqueous dispersion of TOCN-Na with a solids concentration of 1.0%. Furthermore, in the step of "Preparation of Foaming Composition" in Production Example 1, 200 g of the above polymer latex (solid content concentration: 58%) was weighed into a 500 ml disposable cup and stirred (1750 rpm) with a mixer (ROBOMICS, manufactured by Tokushu Kika Kogyo Co., Ltd.). To the stirred polymer latex, 53.6 g (0.5 parts by mass of TOCN-Na content per 100 parts by mass of polymer) of the above TOCN-Na aqueous dispersion (solid content concentration: 1.0%) was gradually added in small amounts, and stirring was continued for 30 minutes after the addition. Subsequently, while stirring the resulting mixture, 8.02 g of ammonium stearate (30% concentration, manufactured by San Nopco Co., Ltd., Nopco DC-100A) as a foam stabilizer, 6.13 g of fatty acid polyglycidyl ether (100% concentration, manufactured by Japan Coating Resins Co., Ltd., Rikabond EX-8) as an epoxy crosslinker (5.28 parts by mass of epoxy crosslinker per 100 parts by mass of polymer), and 8.02 g of sodium polyacrylate (15% concentration, manufactured by Toagosei Co., Ltd.) as a thickener were added in this order, followed by stirring for 30 minutes. The process was carried out in the same manner as in Production Example 1, yielding a foam sheet composition. The foam sheet composition had an active ingredient concentration of 46%, a viscosity of 3,500 mPa·s, and a pH of 9.1. The foam sheet composition was foamed 1.9 times using a whisk (THM272 hand mixer, manufactured by Tescom Co., Ltd.) to a density of 0.41 g / cm. 3 A foaming composition (foaming liquid) of the formula was obtained.

[0136] (Production Example 5) After the "polymer latex preparation" step in Production Example 1, 400 g of the polymer latex (solids concentration 58%) was weighed into a 500 ml disposable cup and stirred at 1750 rpm in a mixer (ROBOMICS, manufactured by Tokushu Kika Kogyo Co., Ltd.). 16.06 g of ammonium stearate (San Nopco DC-100A, 30%) as a foam stabilizer, 12.06 g of fatty acid polyglycidyl ether (Japan Coating Resins, Rikabond EX-8, 100%) as an epoxy crosslinker (epoxy crosslinker content: 5.20 parts by weight per 100 parts by weight of polymer), and 12.09 g of sodium polyacrylate (Toagosei Aron A-20L, 15% by weight as a thickener) were added to the stirred polymer latex in that order, and the mixture was stirred for 30 minutes to obtain a foam sheet composition. The active ingredient concentration of the foam sheet composition was 57%, the viscosity was 5,200 mPa·s, and the pH was 8.4. The foam sheet composition was foamed 1.6 times using a whisk (Tescom Co., Ltd., Hand Mixer THM272) to a density of 0.62 g / cm. 3 A foaming composition (foaming liquid) of the formula was obtained.

[0137] Example 1 The foaming liquid prepared in Production Example 1 was applied to a PET film (Toyobo Co., Ltd., G2R, thickness 50 μm) using an automatic coater (main body: TQC Sheen Co., Ltd. AFA-Standard KT-AB4420, applicator: Cortec Co., Ltd. Multi-applicator MA-250). The applied PET film was placed in an 80°C oven (Yamato Scientific Co., Ltd. DNF400) for 80 seconds, then in a 120°C oven (Yamato Scientific Co., Ltd. DNF400) for 80 seconds, and then in a 140°C oven (Yamato Scientific Co., Ltd. DNF400) for 80 seconds to dry, resulting in a foam layer thickness of 120 μm and a foam layer density of 0.57 g / cm. 3 The laminate sheet was evaluated for its deodorizing ability against hydrogen sulfide gas (100 ppm, 3 L) and its coloring ability. The results are shown in Table 1.

[0138] Example 2 The foaming liquid prepared in Production Example 1 was applied to an OPP film (Futamura Chemical Co., Ltd., FOS-AQBT, thickness 50 μm) and dried in an 80°C oven (Yamato Scientific Co., Ltd., DNF400) for 80 seconds and then in a 120°C oven (Yamato Scientific Co., Ltd., DNF400) for 160 seconds, but was treated and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0139] Example 3 The treatment and evaluation were carried out in the same manner as in Example 1, except that the hydrogen sulfide gas used in the evaluation of deodorizing and coloring properties was changed to a concentration of 85 ppm and a volume of 50 L. The results are shown in Table 1.

[0140] Example 4 The foaming liquid prepared in Production Example 2 was used, and treatment and evaluation were carried out in the same manner as in Example 1, except that the hydrogen sulfide gas used in the evaluation of deodorizing and coloring properties was changed to a concentration of 79 ppm and a volume of 3 L. The results are shown in Table 1.

[0141] Example 5 Treatment and evaluation were carried out in the same manner as in Example 1, except that the foaming liquid prepared in Production Example 3 was used. The results are shown in Table 1.

[0142] Example 6 Foam layer thickness: 80 μm, foam layer density: 0.57 g / cm 3 The same treatment as in Example 1 was carried out except that the laminated sheet was used. The results are shown in Table 1.

[0143] Example 7 The foaming liquid prepared in Production Example 1 was applied to synthetic paper (SDI-80, manufactured by Yupo Co., Ltd., thickness 80 μm) and dried in an oven (DNF400, manufactured by Yamato Scientific Co., Ltd.) at 80°C for 80 seconds, and then in an oven (DNF400, manufactured by Yamato Scientific Co., Ltd.) at 120°C for 160 seconds. Except for this, treatment and evaluation were carried out in the same manner as in Example 1. The results are shown in Table 1.

[0144] Example 8 The produced laminated sheet was cut into a piece of 100 mm x 100 mm x thickness, and the deodorizing properties and coloring properties were evaluated, but the treatment and evaluation were carried out in the same manner as in Example 1. The results are shown in Table 1.

[0145] (Comparative Example 1) Treatment and evaluation were carried out in the same manner as in Example 4, except that the foaming liquid prepared in Production Example 4 was used. The results are shown in Table 1.

[0146] (Comparative Example 2) Treatment and evaluation were carried out in the same manner as in Example 1, except that the foaming liquid prepared in Production Example 5 was used. The results are shown in Table 1.

[0147] (Comparative Example 3) The treatment was carried out in the same manner as in Example 1, except that the deodorizing property against ammonia gas (73 ppm, 3 L) and the coloring property were evaluated. The results are shown in Table 1.

[0148] Comparative Example 4 A 120mm x 120mm x 1mm soda glass without a laminated sheet was placed in a sampling pack (GL Sciences SMART BAG PA AA-5) and its deodorizing effect on hydrogen sulfide gas (100ppm, 3L) in the sampling bag was evaluated. The results are shown in Table 1.

[0149] (Comparative Example 5) The sampling pack (GL Sciences SMART BAG PA AA-5) was left empty and the deodorizing effect against hydrogen sulfide gas (100 ppm, 3 L) in the sampling bag was evaluated. The results are shown in Table 1.

[0150] [Table 1]

[0151] Comparing Examples 1-8 with Comparative Examples 1, 2, 4 and 5 in Table 1, it can be seen that the laminates using the sulfur-based gas sensor material of the present invention containing copper ions have excellent deodorizing and coloring properties against sulfur-based gases. Furthermore, when Example 1 is compared with Comparative Example 3, it is found that the laminate including the self-adsorbing foam sheet of the present invention is not discolored by ammonia, but has deodorizing properties against ammonia. In the table, TOCN-M represents metal-containing TEMPO-oxidized cellulose nanofibers, and M represents the contained metal. [Industrial Applicability]

[0152] According to the present invention, a novel sulfur-based gas sensor material can be provided.

Claims

1. A sulfur-based gas sensor material containing copper ions.

2. 2. The sulfur-based gas sensor material according to claim 1, comprising copper-containing oxidized cellulose containing copper in the form of a salt.

3. 3. The sulfur-based gas sensor material according to claim 2, wherein the copper-containing oxidized cellulose is a copper-containing carboxylated cellulose.

4. 3. The sulfur-based gas sensor material according to claim 2, wherein the copper-containing oxidized cellulose is a copper-containing oxidized cellulose nanofiber having a number average fiber diameter of 100 nm or less.

5. 3. The sulfur-based gas sensor material according to claim 2, wherein the number average fiber length of the copper-containing oxidized cellulose is 50 nm or more and 2000 nm or less.

6. 3. The sulfur-based gas sensor material according to claim 2, wherein the copper-containing oxidized cellulose has an average degree of polymerization of 100 or more and 2000 or less.

7. A molded article comprising the sulfur-based gas sensor material according to claim 1.

8. The molded article according to claim 7, which is in the form of a sheet.

9. A self-adsorbing foam sheet comprising the molded article according to claim 8.

10. Density is 0.7 g / cm ３ 10. The self-adsorbing foam sheet of claim 9, wherein:

11. The self-adhesive foam sheet according to claim 9, having a thickness of 100 μm or more.

12. A self-adhesive laminate comprising a substrate and the self-adhesive foam sheet according to claim 9.

13. a step of foaming a composition for a self-adsorbing foam sheet, the composition comprising a polymer and copper-containing oxidized cellulose containing copper in the form of a salt, to obtain a foam composition; and forming the foam composition into a sheet on a substrate.

14. A sulfur-based gas sensor device comprising the molded article according to claim 7 or 8, the self-adsorbing foam sheet according to any one of claims 9 to 11, or the self-adsorbing laminate according to claim 12.

15. 15. The sulfur-based gas sensor device according to claim 14, wherein the molded body, the self-adhesive foam sheet, or the self-adhesive laminate has a circular shape.

16. 15. The sulfur-based gas sensor device according to claim 14, wherein a substrate supporting the molded body, the self-adhesive foam sheet, or the self-adhesive laminate is transparent.

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