Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
  • C09J11/08—Macromolecular additives
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
  • C09J133/04—Homopolymers or copolymers of esters
  • C09J133/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J7/00—Adhesives in the form of films or foils
  • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
  • C09J7/38—Pressure-sensitive adhesives [PSA]

Definitions

• the present invention relates to adhesive tapes.
• Adhesive tapes having an adhesive layer containing an adhesive have been widely used for fixing electronic parts, vehicles, houses and building materials (for example, Patent Documents 1 to 3). Specifically, for example, an adhesive tape is used to adhere a cover panel for protecting the surface of a portable electronic device to a touch panel module or a display panel module, or to adhere a touch panel module and a display panel module. ing.
• An object of the present invention is to provide an adhesive tape that has a high biogenic carbon content, exhibits excellent adhesive strength, and has reduced odor generation.
• the present disclosure 1 is a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer containing an acrylic copolymer, wherein the acrylic copolymer contains a structural unit derived from an alkyl (meth)acrylate containing biological carbon.
• the acrylic copolymer is a pressure-sensitive adhesive tape containing less than 0.5% by weight of a structural unit derived from a (meth)acrylate having a branched alkyl group with 8 or less carbon atoms.
• the present disclosure 2 is the adhesive tape of the present disclosure 1, wherein the alkyl (meth)acrylate containing biological carbon contains n-heptyl (meth)acrylate.
• Present Disclosure 3 is the pressure-sensitive adhesive tape according to Present Disclosure 1 or 2, wherein the (meth)acrylate having a branched alkyl group having 8 or less carbon atoms contains 1-methylheptyl (meth)acrylate.
• Present Disclosure 4 is the pressure-sensitive adhesive tape according to Present Disclosure 1, 2, or 3, wherein the acrylic copolymer contains 85% by weight or more of structural units derived from n-heptyl(meth)acrylate.
• This disclosure 5 is the pressure-sensitive adhesive tape of present disclosure 1, 2, 3, or 4, wherein the pressure-sensitive adhesive layer further contains a tackifying resin.
• Present Disclosure 6 is the pressure-sensitive adhesive tape according to Present Disclosure 1, 2, 3, 4, or 5, wherein the pressure-sensitive adhesive layer has a total amount of volatile organic compounds in terms of toluene of less than 1000 ppm.
• Present Disclosure 7 is the pressure-sensitive adhesive tape according to Present Disclosure 1, 2, 3, 4, 5, or 6, wherein the pressure-sensitive adhesive layer has a biological carbon content of 10% by weight or more.
• the present disclosure 8 is the adhesive tape according to the present disclosure 1, 2, 3, 4, 5, 6 or 7, which is used for fixing electronic device parts or vehicle-mounted parts.
• (meth)acrylate means acrylate or methacrylate
• (meth)acryl means acrylic or methacrylic.
• the acrylic copolymer may be a methacrylic copolymer.
• the present inventors have found that in a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer containing an acrylic copolymer, an alkyl (meth)acrylate containing biological carbon is used as an acrylic monomer constituting the acrylic copolymer. investigated. However, when an alkyl (meth)acrylate containing biological carbon is used, although the adhesive tape can exhibit excellent adhesive strength, a new problem arises in that an odor is generated.
• Alkyl (meth)acrylates containing biologically-derived carbon are mainly produced by esterification of (meth)acrylic acid with an alcohol having a biologically-derived alkyl group, or (meth)acrylic acid esters (e.g., (meth) ) methyl acrylate) and an alcohol having a biological alkyl group.
• the alcohol having a biologically derived alkyl group is obtained, for example, by cracking or reducing a biologically derived fatty acid or an ester thereof.
• These alcohols contain alcohols having branched chain alkyl groups as impurities.
• alkyl (meth)acrylates containing biological carbon obtained from these alcohols may also contain (meth)acrylates having branched-chain alkyl groups or unsaturated alkyl groups as impurities.
• (Meth)acrylates having such branched chain alkyl groups are copolymerized into acrylic copolymers.
• the branched-chain alkyl group is likely to be cleaved by hydrolysis or the like over time. found to do.
• (meth)acrylates having a branched alkyl group with 8 or less carbon atoms tend to cause odor.
• the present inventors have found that by suppressing the content of structural units derived from (meth)acrylates having a branched alkyl group having 8 or less carbon atoms in acrylic copolymers to a certain value or less, bio-derived carbon
• the inventors have found that a pressure-sensitive adhesive tape having a high content can be obtained, which can exhibit excellent adhesive strength while reducing the generation of odor, and have completed the present invention.
• the pressure-sensitive adhesive tape of the present invention has a pressure-sensitive adhesive layer containing an acrylic copolymer.
• the above acrylic copolymer contains a structural unit derived from an alkyl (meth)acrylate containing biological carbon.
• the pressure-sensitive adhesive tape of the present invention has a high biological carbon content and exhibits excellent adhesive strength.
• the alkyl (meth)acrylate containing the biological carbon is not particularly limited, but the glass transition temperature (Tg) of the acrylic copolymer is sufficiently low, and the adhesion of the adhesive layer to the adherend is improved.
• Tg glass transition temperature
• a (meth)acrylate having an alkyl group having 7 to 12 carbon atoms is preferable because it improves the performance.
• (meth)acrylates having a linear alkyl group with 7 to 12 carbon atoms are more preferred.
• Examples of (meth)acrylates having a linear alkyl group having 7 to 12 carbon atoms include n-heptyl (meth)acrylate, n-octyl (meth)acrylate, n-decyl (meth)acrylate, and lauryl (meth)acrylate. etc. These (meth)acrylates having a linear alkyl group of 7 to 12 carbon atoms may be used alone, or two or more of them may be used in combination.
• n-heptyl (meth) acrylate and n-octyl (meth) acrylate are preferable, and n-heptyl (meth) acrylate is preferable because the adhesion of the pressure-sensitive adhesive layer to the adherend is further improved. more preferred.
• the above-mentioned alkyl (meth)acrylate containing biological carbon is not particularly limited as long as it contains biological carbon, and is synthesized by esterification of alcohol, which is a biological material, with (meth)acrylic acid. preferably.
• alcohol which is a biological material
• (meth)acrylic acid preferably, n-heptyl alcohol, which is a biological material, can be obtained inexpensively and easily by cracking raw materials collected from animals and plants (for example, ricinoleic acid derived from castor oil). can be done.
• n-octyl alcohol which is a biological material, can be easily and easily obtained by reducing a material collected from animals and plants (for example, caprylic acid derived from coconut oil) as a raw material.
• lauryl alcohol which is a biological material, can be easily and easily obtained by reducing a material collected from animals and plants (for example, lauric acid derived from palm oil or palm kernel oil) as a raw material. be able to.
• the content of the structural unit derived from the alkyl (meth)acrylate containing the biological carbon in the acrylic copolymer is not particularly limited, but preferably exceeds 50% by weight, and a more preferable lower limit is 60% by weight. A more preferred lower limit is 70% by weight, and a particularly preferred lower limit is 85% by weight.
• the most preferable lower limit of the content of the structural unit is 90% by weight.
• the upper limit of the content of structural units derived from the alkyl (meth)acrylate containing biological carbon is not particularly limited, but from the viewpoint of adjusting the gel fraction of the pressure-sensitive adhesive layer, the preferred upper limit is 99% by weight, A more preferable upper limit is 97% by weight.
• the content of structural units derived from the n-heptyl (meth)acrylate in the acrylic copolymer is more than 50% by weight, more preferably 60% by weight or more, still more preferably 70% by weight or more, and particularly preferably When the amount is 85% by weight or more, the pressure-sensitive adhesive layer has a higher adhesive strength.
• the content of structural units derived from the alkyl (meth) acrylate containing carbon of biological origin in the acrylic copolymer is determined by mass spectrometry and 1 H-NMR measurement of the acrylic copolymer, and is derived from each monomer. can be calculated from the integrated intensity ratio of the hydrogen peaks.
• the acrylic copolymer contains less than 0.5% by weight of structural units derived from a (meth)acrylate having a branched alkyl group having 8 or less carbon atoms, and preferably contains a branched alkyl group.
• the content of structural units derived from (meth)acrylates is less than 0.5% by weight.
• the (meth)acrylate having a branched-chain alkyl group having 8 or less carbon atoms means a (meth)acrylate having 8 or less carbon atoms in the branched-chain alkyl group.
• the (meth)acrylate having a branched chain alkyl group may be produced as an impurity when preparing an alkyl (meth)acrylate containing a specific biological carbon.
• the (meth)acrylate having a branched chain alkyl group may not correspond to the alkyl (meth)acrylate containing carbon of biological origin.
• the content of the structural unit derived from the (meth)acrylate having a branched alkyl group having 8 or less carbon atoms in the acrylic copolymer is less than 0.5% by weight, so that the pressure-sensitive adhesive tape is odorless. Occurrence is reduced.
• the content of the structural unit is preferably 0.1% by weight or less, more preferably less than 0.1% by weight, and even more preferably 0.05% by weight or less.
• the lower limit of the content of the structural unit derived from the (meth)acrylate having a branched alkyl group having 8 or less carbon atoms is not particularly limited, and is preferably close to 0% by weight, and may be 0% by weight. . That is, the acrylic copolymer may not contain a structural unit derived from a (meth)acrylate having a branched alkyl group having 8 or less carbon atoms, or has the branched alkyl group ( It may not contain structural units derived from meth)acrylate.
• the (meth)acrylate having a branched alkyl group having 8 or less carbon atoms is not particularly limited, and examples thereof include 1-methylheptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and 1-methyloctyl (meth)acrylate.
• These (meth)acrylates having a branched alkyl group having 8 or less carbon atoms may be used alone, or two or more of them may be used in combination.
• the alkyl (meth) acrylate containing biological carbon contains n-heptyl (meth) acrylate
• the branched alkyl group having 8 or less carbon atoms examples include 1-methylheptyl (meth)acrylate and 2-ethylhexyl (meth)acrylate.
• the alkyl (meth)acrylate containing carbon derived from a living organism contains n-octyl (meth)acrylate
• the (meth)acrylate having a branched alkyl group having 8 or less carbon atoms may be used, for example , 1-methyloctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate and the like.
• the alkyl (meth)acrylate containing carbon derived from a living organism contains lauryl (meth)acrylate
• the (meth)acrylate having a branched alkyl group having 8 or less carbon atoms may be, for example, 1 -methyldodecyl (meth)acrylate, isododecyl (meth)acrylate and the like.
• the acrylic copolymer is A method of appropriately selecting and using a constituting acrylic monomer may be mentioned. Further, when using an alkyl (meth)acrylate containing carbon derived from a specific organism as an acrylic monomer constituting the acrylic copolymer, the alkyl (meth)acrylate containing carbon derived from a specific organism is purified. By doing so, a method of reducing the content of (meth)acrylate having a specific branched chain alkyl group contained as an impurity is also exemplified. Examples of the purification method include preparative HPLC (liquid chromatography).
• the content of the structural unit derived from the (meth)acrylate having a branched alkyl group having 8 or less carbon atoms in the acrylic copolymer is determined by mass spectrometry and 1 H-NMR measurement of the acrylic copolymer. , can be calculated from the integrated intensity ratio of the hydrogen peaks derived from each monomer.
• the acrylic copolymer preferably further contains a structural unit derived from a monomer having a crosslinkable functional group.
• the acrylic copolymer contains a structural unit derived from a monomer having a crosslinkable functional group, the cohesive force of the pressure-sensitive adhesive layer increases, resulting in a higher adhesive force.
• the monomer having a crosslinkable functional group is not particularly limited, and examples thereof include a monomer having a hydroxyl group, a monomer having a carboxyl group, a monomer having a glycidyl group, a monomer having an amide group, and a monomer having a nitrile group.
• These monomers having a crosslinkable functional group may be used alone, or two or more of them may be used in combination. Among them, a hydroxyl group-containing monomer and a carboxyl group-containing monomer are preferable, and a hydroxyl group-containing monomer is more preferable, since the gel fraction of the pressure-sensitive adhesive layer can be easily adjusted.
• Examples of the monomer having a hydroxyl group include acrylic monomers having a hydroxyl group such as 4-hydroxybutyl (meth)acrylate and 2-hydroxyethyl (meth)acrylate.
• Examples of the monomer having a carboxyl group include acrylic monomers having a carboxyl group such as (meth)acrylic acid.
• Examples of the monomer having a glycidyl group include acrylic monomers having a glycidyl group such as glycidyl (meth)acrylate.
• Examples of monomers having an amide group include (meth)acrylamide, dimethyl(meth)acrylamide, diethyl(meth)acrylamide, isopropyl(meth)acrylamide, t-butyl(meth)acrylamide, methoxymethyl(meth)acrylamide, butoxymethyl
• Examples of the nitrile group-containing monomer include acrylic monomers having a nitrile group such as (meth)acrylonitrile.
• the content of the structural unit derived from the monomer having a crosslinkable functional group in the acrylic copolymer is not particularly limited, but the preferred lower limit is 0.01% by weight and the preferred upper limit is 15% by weight.
• the content of the structural unit derived from the monomer having the crosslinkable functional group is within the above range, the cohesive force of the pressure-sensitive adhesive layer is further increased, and the adhesive force is further increased.
• a more preferable lower limit for the content of structural units derived from the monomer having a crosslinkable functional group is 0.1% by weight, a more preferable upper limit is 10% by weight, a still more preferable lower limit is 0.5% by weight, and a further preferable upper limit is is 5% by weight.
• the content of the structural unit derived from the monomer having a crosslinkable functional group in the acrylic copolymer is determined by mass spectrometry and 1 H-NMR measurement of the acrylic copolymer, and the peak of hydrogen derived from each monomer. It can be calculated from the integrated intensity ratio.
• the acrylic copolymer has a structural unit derived from the biological carbon-containing alkyl (meth) acrylate, a structural unit derived from the (meth) acrylate having a branched alkyl group, and the crosslinkable functional group.
• the structural units derived from monomers it may have structural units derived from other monomers.
• the above-mentioned other monomers are not particularly limited, and examples thereof include alkyl (meth)acrylates (petroleum-derived monomers) having an alkyl group having 7 to 12 carbon atoms, which do not contain biological carbon, and (meth)acrylic acid alkyl esters. mentioned.
• Examples of the (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, myristyl (meth)acrylate, Acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, ester of 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)octanol-1 and (meth)acrylic acid, linear esters of (meth)acrylic acid, behenyl (meth)acrylates, arachidyl (meth)acrylates, and the like, and alcohols having 18 total carbon atoms and having 1 or 2 methyl groups in the main chain.
• These (meth)acrylic acid alkyl esters may be used alone or in combination of two or more.
• the other monomers for example, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate, 2-butoxyethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, tetrahydrofurfuryl ( Meth)acrylates, polypropylene glycol mono(meth)acrylates, and the like may also be mentioned, and isobornyl (meth)acrylates are preferred from the viewpoint of excellent rebound resistance.
• vinyl carboxylates such as vinyl acetate
• various monomers used in general acrylic polymers such as styrene can also be used.
• polyfunctional monomers such as 1,6-hexanediol di(meth)acrylate can be used as the other monomers. These other monomers may be used alone or in combination of two or more.
• the content of structural units derived from the other monomers in the acrylic copolymer is determined by mass spectrometry and 1 H-NMR measurement of the acrylic copolymer, and from the integrated intensity ratio of hydrogen peaks derived from each monomer. can be calculated.
• the monomer having a crosslinkable functional group and the other monomer preferably contain biogenic carbon, but may be made of only petroleum-derived materials without biogenic carbon.
• the acrylic monomers constituting the acrylic copolymer can all be biogenic carbon-containing monomers. From the viewpoint of the cost and productivity of the pressure-sensitive adhesive tape, a relatively inexpensive and readily available biogenic carbon-containing monomer may be used in combination with a monomer consisting solely of a petroleum-derived material.
• the glass transition temperature (Tg) of the acrylic copolymer is not particularly limited, it is preferably ⁇ 20° C. or lower. If the acrylic copolymer has a glass transition temperature (Tg) of ⁇ 20° C. or lower, the adhesion of the pressure-sensitive adhesive layer to the adherend is improved, resulting in a higher adhesive force.
• the glass transition temperature (Tg) of the acrylic copolymer is more preferably ⁇ 30° C. or lower, still more preferably ⁇ 40° C. or lower, and even more preferably ⁇ 50° C. or lower.
• the lower limit of the glass transition temperature (Tg) of the acrylic copolymer is not particularly limited, and is usually ⁇ 90° C. or higher, preferably ⁇ 80° C. or higher.
• the glass transition temperature (Tg) of the acrylic copolymer can be determined, for example, by differential scanning calorimetry.
• the weight average molecular weight (Mw) of the acrylic copolymer is not particularly limited, the preferred lower limit is 200,000 and the preferred upper limit is 2,000,000. When the weight average molecular weight of the acrylic copolymer is within the above range, the pressure-sensitive adhesive layer has a higher adhesive strength.
• a more preferable lower limit of the weight average molecular weight of the acrylic copolymer is 400,000, a more preferable upper limit is 1,800,000, a still more preferable lower limit is 500,000, and a further preferable upper limit is 1,500,000.
• the weight average molecular weight (Mw) is the weight average molecular weight in terms of standard polystyrene by GPC (Gel Permeation Chromatography) measurement.
• the acrylic copolymer was diluted 50-fold with tetrahydrofuran (THF), and the resulting diluted solution was filtered through a filter (material: polytetrafluoroethylene, pore diameter: 0.2 ⁇ m) to obtain a measurement sample. to prepare.
• this measurement sample is supplied to a gel permeation chromatograph (manufactured by Waters, trade name "2690 Separations Module” or equivalent), and GPC measurement is performed under the conditions of a sample flow rate of 1 ml/min and a column temperature of 40 ° C. conduct.
• the polystyrene-equivalent molecular weight of the acrylic copolymer is measured, and this value is defined as the weight-average molecular weight of the acrylic copolymer.
• the acrylic copolymer can be obtained by radically reacting a raw material monomer mixture in the presence of a radical polymerization initiator.
• the method of radical reaction is not particularly limited, and examples thereof include living radical polymerization and free radical polymerization. According to living radical polymerization, a copolymer having a more uniform molecular weight and composition can be obtained as compared with free radical polymerization, and the generation of low molecular weight components and the like can be suppressed. rises and becomes more sticky.
• the polymerization method is not particularly limited, and conventionally known methods can be used.
• polymerization method examples include solution polymerization (boiling point polymerization or constant temperature polymerization), UV polymerization, emulsion polymerization, suspension polymerization, bulk polymerization and the like.
• solution polymerization and UV polymerization are preferable because the adhesive strength of the pressure-sensitive adhesive layer is increased.
• solution polymerization is more preferable because it is easy to mix the tackifying resin with the obtained acrylic copolymer and the adhesive strength of the pressure-sensitive adhesive layer can be further increased.
• reaction solvents include ethyl acetate, toluene, methyl ethyl ketone, dimethyl sulfoxide, ethanol, acetone, and diethyl ether. These reaction solvents may be used alone or in combination of two or more.
• the radical polymerization initiator is not particularly limited, and examples thereof include organic peroxides and azo compounds.
• organic peroxide include 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane, t-hexylperoxypivalate, t-butylperoxypivalate, 2,5 -dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxy isobutyrate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate and the like.
• Examples of the azo compound include azobisisobutyronitrile and azobiscyclohexanecarbonitrile. These radical polymerization initiators may be used alone or in combination of two or more.
• examples of the radical polymerization initiator include organic tellurium polymerization initiators.
• the organic tellurium polymerization initiator is not particularly limited as long as it is generally used for living radical polymerization, and examples thereof include organic tellurium compounds and organic telluride compounds.
• an azo compound may be used as the radical polymerization initiator for the purpose of accelerating the polymerization rate.
• the pressure-sensitive adhesive layer preferably does not contain a surfactant. Since the pressure-sensitive adhesive layer does not contain a surfactant, the pressure-sensitive adhesive strength of the pressure-sensitive adhesive tape, especially at high temperatures, becomes higher.
• the pressure-sensitive adhesive layer containing no surfactant means that the content of the surfactant in the pressure-sensitive adhesive layer is 3% by weight or less, preferably 1% by weight or less.
• the content of the surfactant can be determined, for example, by measuring the pressure-sensitive adhesive layer using a liquid chromatography mass spectrometer (e.g., NEXCERA manufactured by Shimadzu Corporation, Exactive manufactured by Thermo Fisher Scientific, etc.). . More specifically, the ethyl acetate solution of the adhesive layer is filtered through a filter (material: polytetrafluoroethylene, pore diameter: 0.2 ⁇ m). About 10 ⁇ L of the obtained filtrate is injected into a liquid chromatography mass spectrometer and analyzed under the following conditions. The content of the surfactant can be obtained from the area ratio of the peak corresponding to the surfactant in the pressure-sensitive adhesive layer.
• a liquid chromatography mass spectrometer e.g., NEXCERA manufactured by Shimadzu Corporation, Exactive manufactured by Thermo Fisher Scientific, etc.
• the ethyl acetate solution of the adhesive layer is filtered through a filter (material: polytetraflu
• the pressure-sensitive adhesive layer preferably further contains a cross-linking agent.
• the cross-linking agent is not particularly limited, and examples thereof include an isocyanate-based cross-linking agent, an aziridine-based cross-linking agent, an epoxy-based cross-linking agent, and a metal chelate-type cross-linking agent. Among them, an isocyanate-based cross-linking agent is preferable because the pressure-sensitive adhesive layer has excellent adhesion to the adherend.
• the molecular weight of the cross-linking agent is not particularly limited, the molecular weight is preferably less than 2000, preferably 100 or more, from the viewpoint of production.
• the content of the cross-linking agent in the pressure-sensitive adhesive layer is not particularly limited, but the preferred lower limit is 0.05 parts by weight and the preferred upper limit is 7 parts by weight with respect to 100 parts by weight of the acrylic copolymer.
• the content of the cross-linking agent is within the above range, the gel fraction of the pressure-sensitive adhesive layer is appropriately adjusted, and the pressure-sensitive adhesive strength is further increased.
• a more preferable lower limit of the content of the cross-linking agent is 0.1 parts by weight, and a more preferable upper limit thereof is 5 parts by weight.
• content of the said crosslinking agent shows the amount of solid content of the said crosslinking agent.
• the pressure-sensitive adhesive layer preferably further contains a tackifying resin.
• the tackifying resin include rosin ester-based tackifying resins, terpene-based tackifying resins, coumarone-indene-based tackifying resins, alicyclic saturated hydrocarbon-based tackifying resins, and C5-based petroleum tackifying resins. , C9 petroleum tackifying resins, C5-C9 copolymer petroleum tackifying resins, and the like. These tackifying resins may be used alone or in combination of two or more. Among these, at least one selected from the group consisting of rosin ester-based tackifying resins and terpene-based tackifying resins is preferable.
• Examples of the rosin ester-based tackifying resin include polymerized rosin ester-based resins and hydrogenated rosin ester-based resins.
• Examples of the terpene-based tackifying resin include terpene-based resins and terpene-phenolic resins.
• the rosin ester-based tackifying resin and the terpene-based tackifying resin are preferably of biological origin.
• Examples of rosin ester-based tackifying resins derived from organisms include rosin ester-based tackifying resins derived from natural resins such as rosin.
• Terpene-based tackifying resins derived from organisms include, for example, terpene-based tackifying resins derived from plant essential oils and the like.
• the content of the tackifying resin in the pressure-sensitive adhesive layer is not particularly limited, but the preferred lower limit is 10 parts by weight and the preferred upper limit is 60 parts by weight with respect to 100 parts by weight of the acrylic copolymer. If the content of the tackifier resin is within the above range, the adhesive strength of the adhesive layer will be higher.
• the more preferable lower limit of the content of the tackifying resin is 15 parts by weight, the more preferable upper limit is 50 parts by weight, and the more preferable upper limit is 35 parts by weight.
• the pressure-sensitive adhesive layer may contain additives such as silane coupling agents, plasticizers, softeners, fillers, pigments and dyes, if necessary.
• the pressure-sensitive adhesive layer preferably has a total volatile organic compound content of less than 1000 ppm in terms of toluene. If the total amount of volatile organic compounds is less than 1000 ppm, the generation of odor from the adhesive tape is further reduced. More preferably, the total amount of volatile organic compounds is less than 900 ppm.
• the pressure-sensitive adhesive layer preferably has a total volatile organic compound content of less than 1000 ppm in terms of toluene measured immediately after production. If the total amount of volatile organic compounds immediately after production is less than 1000 ppm, the generation of odor from the adhesive tape is further reduced. More preferably, the total amount of volatile organic compounds immediately after production is less than 900 ppm.
• the pressure-sensitive adhesive layer preferably has a total volatile organic compound content of less than 1000 ppm in terms of toluene measured after 60 days or more from the production. If the total amount of volatile organic compounds after 60 days or more from the production is less than 1000 ppm, the generation of odor from the pressure-sensitive adhesive tape is further reduced. More preferably, the total amount of volatile organic compounds after 60 days or more from the production is less than 900 ppm. Note that “immediately after production” means within 7 days from the time the adhesive tape is produced, and "after 60 days or more from production” means after 60 days or more have passed since the time the adhesive tape was produced. It means that there is
• Methods for adjusting the total amount of volatile organic compounds within the above range include, for example, a method of appropriately selecting and using acrylic monomers constituting the acrylic copolymer, and a method of using heat drying temperature and time in the adhesive tape manufacturing process.
• the method of adjustment, the method of storing in a well-ventilated warehouse, etc. can be mentioned.
• the alkyl (meth)acrylate containing carbon derived from a specific organism is purified. By doing so, a method of reducing the content of (meth)acrylate having a specific branched chain alkyl group contained as an impurity is also exemplified. Examples of the purification method include preparative HPLC (liquid chromatography).
• the gel fraction of the pressure-sensitive adhesive layer is not particularly limited, but the preferred lower limit is 10% by weight and the preferred upper limit is 70% by weight. When the gel fraction of the pressure-sensitive adhesive layer is within the above range, the adhesion of the pressure-sensitive adhesive layer to the adherend is improved, and the adhesive strength is further increased. A more preferable lower limit of the gel fraction of the pressure-sensitive adhesive layer is 20% by weight, and a more preferable upper limit thereof is 50% by weight.
• the gel fraction of the adhesive layer is measured as follows. First, the adhesive tape was cut into a flat rectangular shape of 20 mm ⁇ 40 mm to prepare a test piece, and the test piece was immersed in ethyl acetate at 23 ° C.
• the method of adjusting the gel fraction of the pressure-sensitive adhesive layer to the above range is not particularly limited, but the method of adjusting the composition and weight average molecular weight of the acrylic copolymer, and the type and amount of the cross-linking agent as described above. is preferred.
• the pressure-sensitive adhesive layer preferably has a biological carbon content of 10% by weight or more.
• a "bio-based product” is defined as having a bio-derived carbon content of 10% by weight or more. If the content of the biogenic carbon is 10% by weight or more, it is preferable from the viewpoint of saving petroleum resources and reducing carbon dioxide emissions. A more preferable lower limit of the content of the biogenic carbon is 30% by weight, and a further preferable lower limit is 60% by weight.
• the upper limit of the biogenic carbon content is not particularly limited, and may be 100% by weight. It should be noted that carbon derived from organisms contains a certain proportion of radioactive isotope (C-14), whereas carbon derived from petroleum contains almost no C-14. Therefore, the biogenic carbon content can be calculated by measuring the concentration of C-14 contained in the pressure-sensitive adhesive layer. Specifically, it can be measured according to ASTM D6866-20, which is a standard used in many bioplastic industries.
• the thickness of the pressure-sensitive adhesive layer is not particularly limited, but the preferred lower limit is 3 ⁇ m and the preferred upper limit is 300 ⁇ m. If the thickness of the pressure-sensitive adhesive layer is within the above range, the adhesive strength of the pressure-sensitive adhesive layer will be higher. A more preferable lower limit of the thickness of the pressure-sensitive adhesive layer is 5 ⁇ m, and a further preferable lower limit is 10 ⁇ m. A more preferable upper limit of the thickness of the pressure-sensitive adhesive layer is 200 ⁇ m, and a further preferable upper limit is 100 ⁇ m.
• the glass transition temperature (Tg) of the pressure-sensitive adhesive layer is not particularly limited, it is preferably 10° C. or lower. If the glass transition temperature (Tg) of the pressure-sensitive adhesive layer is 10° C. or less, the adhesion to the adherend will be further improved, and the adhesive strength will be further increased.
• the glass transition temperature (Tg) of the pressure-sensitive adhesive layer is more preferably 5° C. or lower, still more preferably 3° C. or lower, and even more preferably 0° C. or lower.
• the lower limit of the glass transition temperature (Tg) of the pressure-sensitive adhesive layer is not particularly limited, and is usually ⁇ 90° C. or higher, preferably ⁇ 80° C. or higher.
• the glass transition temperature (Tg) of the pressure-sensitive adhesive layer can be determined by, for example, a polymer dynamic viscoelasticity measuring device "itkDVA-200" (manufactured by IT Keisoku Kogyo Co., Ltd.).
• the pressure-sensitive adhesive tape of the present invention may be a non-support tape having no substrate, or may be a single-sided pressure-sensitive adhesive tape having an adhesive layer on one side of the substrate. It may be a double-sided adhesive tape having
• the substrate is not particularly limited, and conventionally known substrates can be used. However, in order to increase the biogenic carbon content of the adhesive tape as a whole, it is possible to use a biogenic substrate. preferable.
• the biological-derived substrate include plant-derived polyethylene terephthalate (PET), polyethylene furanoate (PEF), polylactic acid (PLA), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), and polybutylene.
• PET polyester
• PBS succinate
• PET polyethylene
• PP polypropylene
• PU polyurethane
• TAC triacetyl cellulose
• PA polyamide
• the substrate is preferably a PES film or a PA film.
• a film made of PA is preferable.
• the composition of the PA film include nylon 11, nylon 1010, nylon 610, nylon 510, and nylon 410 made from castor oil, and nylon 56 made from cellulose.
• a base material using recycled resources may be used.
• waste such as packaging containers, home appliances, automobiles, construction materials, food, etc., and waste generated in the manufacturing process are collected, and the removed materials are washed, decontaminated, or There is a method of reusing it as a raw material by decomposition by heating or fermentation.
• substrates using recycled resources include films and non-woven fabrics made of PET, PBT, PE, PP, PA, etc., which use recycled plastics as raw materials.
• the collected waste may be burned and used as heat energy related to the production of base materials and raw materials thereof, and the fats and oils contained in the collected waste are mixed with petroleum, fractionally distilled, and refined. It can be used as a raw material.
• the base material may be a foam base material from the viewpoint of improving compression characteristics.
• a foam base material made of PE, PP and/or PU is preferable, and a foam base material made of PE is more preferable from the viewpoint of achieving a high degree of compatibility between flexibility and strength.
• Examples of the composition of the foam base material made of PE include PE made from sugarcane.
• the method for producing the foam base material is not particularly limited.
• a preferred method is to foam the foaming agent when the resin composition is extruded into a sheet, and to crosslink the resulting polyolefin foam as necessary.
• the thickness of the foam base material is not particularly limited, but the preferred lower limit is 50 ⁇ m and the preferred upper limit is 5000 ⁇ m. When the thickness of the foam base material is within this range, it is possible to exhibit high flexibility that enables adhesion along the shape of the adherend while exhibiting high impact resistance.
• a more preferable upper limit of the thickness of the foam base material is 1000 ⁇ m, and a further preferable upper limit is 300 ⁇ m.
• the total thickness of the pressure-sensitive adhesive tape (the total thickness of the substrate and the pressure-sensitive adhesive layer) preferably has a lower limit of 3 ⁇ m and a preferred upper limit of 6000 ⁇ m. If the total thickness of the adhesive tape is within the above range, the adhesive strength will be higher. A more preferable upper limit of the total thickness of the adhesive tape is 1200 ⁇ m, and a further preferable upper limit is 500 ⁇ m.
• the production method of the pressure-sensitive adhesive tape of the present invention is not particularly limited, and it can be produced by a conventionally known production method.
• a solution of adhesive A is prepared by adding a solvent to an acrylic copolymer and, if necessary, a cross-linking agent, a tackifying resin, etc., and this solution of adhesive A is applied to the surface of a base material, and the solution is The solvent inside is completely removed by drying to form an adhesive layer A.
• a release film is overlaid on the formed pressure-sensitive adhesive layer A so that the release-treated surface faces the pressure-sensitive adhesive layer A. As shown in FIG.
• a release film different from the release film is prepared, and a solution of adhesive B prepared in the same manner as above is applied to the release-treated surface of this release film, and the solvent in the solution is removed.
• a laminate film having an adhesive layer B formed on the surface of the release film is produced.
• the laminate film thus obtained is superimposed on the back surface of the substrate on which the adhesive layer A is formed so that the adhesive layer B faces the back surface of the substrate to prepare a laminate.
• by pressing the laminate with a rubber roller or the like it is possible to obtain a double-sided pressure-sensitive adhesive tape having pressure-sensitive adhesive layers on both sides of the base material and the surfaces of the pressure-sensitive adhesive layers covered with a release film. .
• two sets of laminated films are prepared in the same manner, and these laminated films are laminated on both sides of the base material with the pressure-sensitive adhesive layer of the laminated film facing the base material to prepare a laminate.
• a double-sided pressure-sensitive adhesive tape having pressure-sensitive adhesive layers on both sides of a base material and surfaces of the pressure-sensitive adhesive layers covered with a release film may be obtained by pressing this laminate with a rubber roller or the like.
• the application of the adhesive tape of the present invention is not particularly limited, but it has a high content of biological carbon, can exhibit excellent adhesive strength, and has reduced odor generation, so it is suitable for use in electronic equipment parts or in-vehicle parts. It is preferably used for fixing parts.
• the pressure-sensitive adhesive tape of the present invention can be suitably used for adhesion and fixation of electronic device parts in large portable electronic devices, adhesion and fixation of in-vehicle parts (for example, in-vehicle panels), and the like.
• an adhesive tape that has a high biogenic carbon content, exhibits excellent adhesive strength, and has reduced odor generation.
• n-octyl acrylate was prepared by esterifying n-octyl alcohol (manufactured by Kao Corporation) containing biological carbon and acrylic acid (manufactured by Nippon Shokubai Co., Ltd.). At this time, the content of impurities was reduced by purifying n-octyl acrylate using a preparative HPLC (liquid chromatography) device (Inertsil SIL-150A, manufactured by GL Sciences).
• n-Heptyl Acrylate Containing Biological Carbon Ricinoleic acid derived from castor oil was cracked to give a mixture containing undecylenic acid and heptyl alcohol. Then, by separating from undecylenic acid by distillation, n-heptyl alcohol containing biological carbon was obtained. The obtained n-heptyl alcohol was esterified with acrylic acid (manufactured by Nippon Shokubai Co., Ltd.) to prepare n-heptyl acrylate. At this time, the content of impurities was reduced by purifying n-heptyl acrylate using a preparative HPLC (liquid chromatography) device (Inertsil SIL-150A, manufactured by GL Sciences).
• a preparative HPLC liquid chromatography
• Example 1 Production of acrylic copolymer Ethyl acetate was added as a polymerization solvent into a reaction vessel, and nitrogen was bubbled through the reaction vessel. Subsequently, a radical polymerization initiator solution obtained by diluting 0.1 part by weight of azobisisobutyronitrile 10 times with ethyl acetate as a radical polymerization initiator was charged into the reaction vessel, and a predetermined amount of n-octyl acrylate and acrylic acid were added. and 2-hydroxyethyl acrylate were added dropwise over 2 hours.
• a radical polymerization initiator solution obtained by diluting 0.1 part by weight of azobisisobutyronitrile 10 times with ethyl acetate as a radical polymerization initiator was charged into the reaction vessel, and a predetermined amount of n-octyl acrylate and acrylic acid were added. and 2-hydroxyethyl acrylate were added dropwise over 2 hours.
• a radical polymerization initiator solution prepared by diluting 0.1 parts by weight of azobisisobutyronitrile 10 times with ethyl acetate as a radical polymerization initiator was put into the reaction vessel again, and the polymerization reaction was performed for 4 hours. A copolymer-containing solution was obtained.
• the obtained acrylic copolymer was subjected to mass spectrometry and 1 H-NMR measurement, and the content (% by weight) of the structural unit derived from each monomer was calculated from the integrated intensity ratio of the hydrogen peak derived from each monomer. .
• the obtained acrylic copolymer was diluted 50-fold with tetrahydrofuran (THF), and the diluted solution obtained was filtered through a filter (material: polytetrafluoroethylene, pore diameter: 0.2 ⁇ m) to prepare a measurement sample.
• This measurement sample is supplied to a gel permeation chromatograph (manufactured by Waters, 2690 Separations Module), and GPC measurement is performed under the conditions of a sample flow rate of 1 mL/min and a column temperature of 40°C to measure the polystyrene equivalent molecular weight of the acrylic copolymer. to determine the weight average molecular weight.
• the glass transition temperature (Tg) of the obtained acrylic copolymer was obtained by measuring the storage elastic modulus G′ and the loss elastic modulus G′′ at each temperature with a polymer dynamic viscoelasticity measuring device “itkDVA-200” (ITKDVA-200). (manufactured by Keisoku Kogyo Co., Ltd.) under the following conditions, tan ⁇ at each temperature was calculated, and Tg, which is the peak value of tan ⁇ , was measured.
• Measurement mode Shear Heating rate: 5°C/min Measurement temperature range: -30 to 150°C Set distortion: 0.1% Frequency: 10Hz
• the acrylic copolymer-containing solution was molded so that the final sample shape had a thickness of 0.1 mm, a width of 0.6 mm, and a length of 10 mm, and was measured under the same conditions as when forming the pressure-sensitive adhesive layer. It was prepared by heating and drying.
• the release film on one side of the adhesive tape was peeled off, and a 23 ⁇ m-thick PET film (FE2002, manufactured by Futamura Chemical Co., Ltd.) was adhered to the adhesive tape, which was then cut into a flat rectangular shape of 20 mm ⁇ 40 mm. Furthermore, the release film on the other side of the adhesive tape was peeled off to prepare a test piece, and the weight was measured. After the test piece was immersed in ethyl acetate at 23° C. for 24 hours, it was removed from the ethyl acetate and dried at 110° C. for 1 hour. The weight of the test piece after drying was measured, and the gel fraction was calculated using the following formula (2).
• Tg glass transition temperature
• Measurement mode Shear Heating rate: 5°C/min Measurement temperature range: -30 to 150°C Set distortion: 0.1% Frequency: 10Hz
• the measurement sample is formed by molding the pressure-sensitive adhesive solution so that the finally obtained sample shape has a thickness of 0.1 mm, a width of 0.6 mm, and a length of 10 mm, and is heated and dried under the same conditions as when forming the pressure-sensitive adhesive layer. It was made by
• Example 2 The type and amount of the acrylic monomer constituting the acrylic copolymer, the weight average molecular weight of the acrylic copolymer, the type and amount of the tackifying resin, and the amount of the cross-linking agent were changed as shown in Table 1.
• An adhesive tape was obtained in the same manner as in Example 1.
• Example 4 An adhesive tape was obtained in the same manner as in Example 3, except that a preparative HPLC (liquid chromatography) device (Inertsil SIL-100A, manufactured by GL Sciences Inc.) was used to purify n-heptyl acrylate.
• a preparative HPLC (liquid chromatography) device Inertsil SIL-100A, manufactured by GL Sciences Inc.
• Example 2 A pressure-sensitive adhesive tape was obtained in the same manner as in Example 1, except that a predetermined amount of 1-methylheptyl acrylate was further added to the raw material monomer mixture.
• Example 3 A pressure-sensitive adhesive tape was obtained in the same manner as in Example 3, except that a predetermined amount of 2-ethylhexyl acrylate was further added to the raw material monomer mixture.
• this test sample was peeled in the direction of 180° at a tensile speed of 300 mm/min, and the adhesive strength (N/25 mm) was measured.
• the measured 180° peel strength exceeded 20 N/25 mm, it was evaluated as ⁇ , when it exceeded 10 N/25 mm but was 20 N/25 mm or less, and when it was 10 N/25 mm or less, it was evaluated as ⁇ .
• Odor generation was evaluated according to VDA270.
• a 1 L glass bottle was sealed with 50 cm 2 of adhesive tape and allowed to stand in an atmosphere of 40° C. for 24 hours. After standing still for 24 hours, the odor immediately after taking out the adhesive tape was evaluated by the following 6-point method. Three or more panelists evaluated each, and the average value was obtained. When the average value was 1, it was evaluated as ⁇ , when it was 2 to 3, it was evaluated as ⁇ , and when it was 4 to 6, it was evaluated as ⁇ . 1: not perceptible 2: perceptible but not unpleasant 3: clearly perceptible but not very unpleasant 4: unpleasant 5: very unpleasant 6: intolerable
• an adhesive tape that has a high biogenic carbon content, exhibits excellent adhesive strength, and has reduced odor generation.

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• 2022
  • 2022-06-23 TW TW111123457A patent/TW202309228A/zh unknown
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