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
  • 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
  • C09J133/08—Homopolymers or copolymers of acrylic acid esters
• • 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
  • C09J133/10—Homopolymers or copolymers of methacrylic acid esters
• • 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
  • C09J175/00—Adhesives based on polyureas or polyurethanes; Adhesives based on derivatives of such polymers
  • C09J175/04—Polyurethanes
• • 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.
• Patent Literature 1 describes a re-peelable pressure-sensitive adhesive tape for packaging having, on at least one surface of a base material, a pressure-sensitive adhesive layer made of a specific pressure-sensitive adhesive containing a plasticizer.
• Such an adhesive tape is desired to be easily peelable without damaging the adherend, but if the adhesive strength is too low, the tape will peel during use.
• the adhesive tape may not adhere sufficiently to the adherend.
• the stickiness to a non-smooth surface can be improved by increasing the thickness of the pressure-sensitive adhesive layer, in general, the thicker the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape, the higher the adhesive strength. For this reason, it has been difficult to obtain a pressure-sensitive adhesive layer that can be sufficiently attached to an adherend and that can be easily peeled off from the adherend while having a certain thickness or more.
• An object of the present invention is to provide a pressure-sensitive adhesive tape which has excellent sticking properties to non-smooth surfaces such as paper and which can be easily peeled off without damaging the adherend.
• the present invention is a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer has a shear storage elastic modulus of 1 ⁇ 10 4 Pa or more and 5 ⁇ 10 4 Pa or less at 23° C. and 1 Hz, and 180°
• the adhesive tape has an adhesive strength of 0.3 N/25 mm or more and 0.7 N/25 mm or less and a thickness of 30 ⁇ m or more.
• the present inventors have found that in a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer with a thickness of 30 ⁇ m or more, the shear storage modulus of the pressure-sensitive adhesive layer at 23° C. and 1 Hz is adjusted to a specific relatively low range, and the pressure-sensitive adhesive layer Consideration was given to adjusting the 180° tack to a specific, relatively low range.
• the present inventors have found that such an adhesive tape has an adhesive layer having a certain thickness or more, has excellent adhesion to non-smooth surfaces such as paper, and can be easily applied without damaging the adherend.
• the inventors have found that the film can be peeled off easily, and have completed the present invention.
• the adhesive tape of the present invention is an adhesive tape having an adhesive layer.
• the pressure-sensitive adhesive layer has a shear storage modulus at 23° C. and 1 Hz with a lower limit of 1 ⁇ 10 4 Pa and an upper limit of 5 ⁇ 10 4 Pa. If the shear storage elastic modulus is 1 ⁇ 10 4 Pa or more, the shape can be sufficiently retained even if the pressure-sensitive adhesive layer has a certain thickness or more. When the shear storage elastic modulus is 5 ⁇ 10 4 Pa or less, the pressure-sensitive adhesive layer easily conforms to a non-smooth surface such as paper, thereby improving the sticking property.
• the preferred lower limit of the shear storage modulus is 1.5 ⁇ 10 4 Pa
• the preferred upper limit is 4 ⁇ 10 4 Pa
• the more preferred lower limit is 1.7 ⁇ 10 4 Pa
• the more preferred upper limit is 3 ⁇ 10 4 Pa.
• a more preferable lower limit is 2 ⁇ 10 4 Pa.
• the shear storage modulus of the pressure-sensitive adhesive layer at 23° C. and 1 Hz can be measured, for example, using a viscoelastic spectrometer (DVA-200, manufactured by IT Keisoku Kogyo Co., Ltd.), etc., using a simple heating mode with a heating rate of 5° C. It can be obtained as the storage elastic modulus at 23°C when the dynamic viscoelasticity spectrum is measured from -40 to 140°C under the condition of 1 Hz/min.
• the shape of the measurement sample at this time is not particularly limited, for example, the pressure-sensitive adhesive layer can be measured as a rectangular shape with a thickness of 1 mm, a length of 10 mm and a width of 6 mm.
• the pressure-sensitive adhesive layer has a 180° adhesive strength with a lower limit of 0.3 N/25 mm and an upper limit of 0.7 N/25 mm.
• the 180° adhesive strength is 0.3 N/25 mm or more, the adhesive layer has appropriate adhesive strength, and the sticking property to non-smooth surfaces such as paper is improved. If the 180° adhesive strength is 0.7 N/25 mm or less, the adhesive strength of the adhesive layer is sufficiently low, so that it can be easily peeled without damaging the adherend during peeling (re-peeling). .
• a preferred lower limit of the 180° adhesive strength is 0.35 N/25 mm, a preferred upper limit is 0.65 N/25 mm, a more preferred lower limit is 0.4 N/25 mm, and a more preferred upper limit is 0.6 N/25 mm.
• the 180° adhesive strength of the adhesive layer can be measured by the following method. Adhesive tape pre-cut to a width of 25 mm and a length of 10 cm is pasted on a polyethylene terephthalate plate of 50 mm in width, 12.5 cm in length and 2 mm in thickness (for example, product name PET-6010 manufactured by Takiron C.I., or equivalent). A sample for measurement is obtained by combining and reciprocating a 2 kg roller once.
• the obtained measurement sample for example, using an autograph (manufactured by Shimadzu Corporation) or the like, according to JIS Z0237: 2009, polyethylene at a tensile speed of 300 mm / min under an environment of a temperature of 23 ° C. and a relative humidity of 50%.
• a peeling test is performed by peeling the adhesive tape off the terephthalate plate in the direction of 180°, and the 180° adhesive strength (N/25 mm) is measured.
• the shear storage modulus at 23 ° C. and 1 Hz of the pressure-sensitive adhesive layer and the 180 ° adhesive strength to the above ranges, for example, the composition and molecular weight (weight average molecular weight) of the base polymer contained in the pressure-sensitive adhesive layer (Mw)), etc., and a method of adjusting the degree of cross-linking (gel fraction) of the pressure-sensitive adhesive layer.
• the adhesive layer is not particularly limited, and examples thereof include an acrylic adhesive layer, a rubber-based adhesive layer, a urethane-based adhesive layer, a silicone-based adhesive layer, and the like.
• an acrylic pressure-sensitive adhesive layer containing a (meth)acrylic polymer is preferable from the viewpoints of easy adjustment of molecular weight, degree of crosslinking, etc., and excellent heat resistance, weather resistance, cost, and the like.
• the (meth)acrylic polymer is a polymer containing structural units derived from (meth)acrylic monomers.
• the (meth)acrylic monomer is not particularly limited, and examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, and pentyl (meth)acrylate.
• a (meth)acrylic acid ester having an alkyl group having 12 or more carbon atoms and having a glass transition temperature (Tg) of 0° C. or less when made into a homopolymer (hereinafter referred to as “(meth)acrylic acid ester (a)” is also preferred). That is, the (meth)acrylic polymer preferably contains a structural unit derived from the (meth)acrylic acid ester (a). Further, a (meth)acrylic acid ester (hereinafter referred to as "(meth) ) Also referred to as “acrylic acid ester (b)”.) is also preferably used in combination.
• the (meth)acrylic polymer further contains structural units derived from the (meth)acrylic ester (b) in addition to the structural units derived from the (meth)acrylic ester (a). is more preferable.
• the (meth)acrylic polymer contains a structural unit having an alkyl group with a relatively long carbon chain
• the pressure-sensitive adhesive layer has a shear storage modulus at 23°C and 1 Hz and a 180° adhesive strength. is easily adjusted within the above range.
• the pressure-sensitive adhesive layer has improved sticking property to a non-smooth surface such as paper, and can be easily peeled off (re-peeled) without damaging the adherend.
• the glass transition temperature (Tg) of the (meth)acrylic acid ester (a) and the (meth)acrylic acid ester (b) is not particularly limited as long as it is 0° C. or lower. From the viewpoint of adjusting the shear storage modulus of and the 180° adhesive strength to a more preferable range, the preferable lower limit is -80°C and the preferable upper limit is -5°C. A more preferable lower limit of the glass transition temperature (Tg) is -70°C, and a more preferable upper limit is -10°C.
• the glass transition temperature (Tg) of the homopolymer is determined by differential scanning calorimetry (T ⁇ Can be measured using a device such as A Instruments Co., Ltd.). More specifically, it is possible to use the value obtained in the 2nd run when the measurement is performed under the conditions of a temperature increase rate of 10° C./min under a nitrogen atmosphere.
• the (meth)acrylic acid ester (a) is not particularly limited, and among the above-mentioned (meth)acrylic monomers, for example, lauryl acrylate (Tg is ⁇ 23° C. when converted to a homopolymer), lauryl methacrylate (homo Tg when converted to a polymer is -65°C). Further examples include isomyristyl acrylate (Tg of -56°C when converted to a homopolymer), isostearyl acrylate (Tg of -18°C when converted to a homopolymer), and the like.
• lauryl acrylate from the group consisting of lauryl acrylate, lauryl methacrylate and isostearyl acrylate, since the shear storage modulus at 23 ° C. and 1 Hz of the pressure-sensitive adhesive layer and the 180 ° adhesive force are easily adjusted to more preferable ranges. At least one selected is preferred. Furthermore, lauryl acrylate is more preferred.
• the content of the structural unit derived from the (meth)acrylic acid ester (a) in the (meth)acrylic polymer is not particularly limited, but the preferred lower limit is 40% by weight.
• the shear storage modulus at 23° C. and 1 Hz and the 180° adhesive strength of the pressure-sensitive adhesive layer are easily adjusted within the above ranges.
• the pressure-sensitive adhesive layer has improved sticking property to a non-smooth surface such as paper, and can be easily peeled off (re-peeled) without damaging the adherend.
• a more preferable lower limit for the content of the structural unit is 45% by weight.
• the upper limit of the content of the structural unit is not particularly limited, but the upper limit is preferably 90% by weight, and the upper limit is more preferably 80% by weight.
• the (meth)acrylic acid ester (b) is not particularly limited, and among the above-mentioned (meth)acrylic monomers, for example, 2-ethylhexyl acrylate (Tg is ⁇ 70° C. when converted to a homopolymer), octyl acrylate (Tg of -65°C when homopolymerized) and the like. Furthermore, isononyl acrylate (Tg is -58°C when converted to homopolymer), isodecyl acrylate (Tg is -62°C when converted to homopolymer), and the like. Among them, 2-ethylhexyl acrylate is preferable because the shear storage modulus of the pressure-sensitive adhesive layer at 23° C. and 1 Hz can easily be adjusted to a more preferable range.
• the content of the structural unit derived from the (meth)acrylic acid ester (b) in the (meth)acrylic polymer is not particularly limited. From the viewpoint of adjusting the shear storage modulus at 23° C. and 1 Hz and the 180° adhesive strength of the pressure-sensitive adhesive layer to more preferable ranges, the preferable lower limit of the content of the structural unit is 20% by weight, and the preferable upper limit is 60. A more preferable lower limit is 30% by weight, and a more preferable upper limit is 50% by weight.
• the (meth)acrylic polymer preferably further contains a structure derived from a crosslinkable functional group-containing monomer. Since the (meth)acrylic polymer contains a structure derived from the crosslinkable functional group-containing monomer, the cohesive force of the pressure-sensitive adhesive layer can be adjusted by cross-linking of the crosslinkable functional group. It becomes easy to adjust the adhesive strength of the layer to the above range, and it becomes easy to adjust the shear storage elastic modulus at 23° C. and 1 Hz to the above range. As a result, the adhesion of the pressure-sensitive adhesive layer to a non-smooth surface such as paper is further improved, and the adhesive layer can be easily peeled off (re-peeled) without damaging the adherend.
• the crosslinkable functional group may or may not be crosslinked, but is more preferably crosslinked. However, even if the structure remains uncrosslinked, the cohesive force of the pressure-sensitive adhesive layer increases due to the interaction between the functional groups.
• crosslinkable functional group-containing monomers examples include monomers containing carboxyl groups, hydroxyl groups, epoxy groups, double bonds, triple bonds, amino groups, amide groups, nitrile groups, and the like. These crosslinkable functional group-containing monomers may be used alone, or two or more of them may be used in combination. Among them, at least one selected from the group consisting of carboxyl group-containing monomers and hydroxyl group-containing monomers is preferable. Hydroxyl group-containing monomers are more preferable because the shear storage modulus of the pressure-sensitive adhesive layer at 23° C. and 1 Hz can be easily adjusted to the above range by cross-linking with an isocyanate-based cross-linking agent.
• the crosslinkable functional group-containing monomer may further contain an alkyl group, an ether group, a carbonyl group, an ester group, a carbonate group, an amide group, a urethane group, or the like.
• Examples of the carboxyl group-containing monomer include (meth)acrylic acid-based monomers such as (meth)acrylic acid.
• Examples of the hydroxyl group-containing monomer include 4-hydroxybutyl (meth)acrylate and 2-hydroxyethyl (meth)acrylate. Glycidyl (meth)acrylate etc. are mentioned as said epoxy-group-containing monomer.
• Examples of the double bond-containing monomer include allyl (meth)acrylate, hexanediol di(meth)acrylate, and the like.
• Examples of the triple bond-containing monomer include propargyl (meth)acrylate.
• Examples of the amide group-containing monomer include (meth)acrylamide.
• the content of the structure derived from the monomer having the crosslinkable functional group is not particularly limited. From the viewpoint of adjustment, the preferable lower limit of the content of the structural unit is 0.1% by weight, and the preferable upper limit is 30% by weight. A more preferable lower limit of the content of the structural unit is 0.5% by weight, and a more preferable upper limit is 25% by weight.
• the content of the structure derived from the hydroxyl group-containing monomer is not particularly limited, but the shear storage modulus of the pressure-sensitive adhesive layer at 23° C. and 1 Hz is adjusted to a more preferable range.
• the preferable lower limit of the content of the structural unit is 1% by weight, and the preferable upper limit is 20% by weight.
• a more preferable lower limit to the content of the structural unit is 3% by weight, and a more preferable upper limit is 10% by weight.
• a monomer mixture containing the (meth)acrylic monomer, the crosslinkable functional group-containing monomer, etc. is radically reacted in the presence of a polymerization initiator, and copolymerized.
• a polymerization method a conventionally known method is used, and examples thereof include solution polymerization (boiling point polymerization or constant temperature polymerization), emulsion polymerization, suspension polymerization, bulk polymerization, and the like.
• the weight average molecular weight (Mw) of the (meth)acrylic polymer is not particularly limited, but the preferred upper limit is 1,000,000.
• the weight average molecular weight (Mw) is 1,000,000 or less, the shear storage elastic modulus at 23° C. and 1 Hz of the pressure-sensitive adhesive layer is easily adjusted to the above range, and the pressure-sensitive adhesive layer has a non-smooth surface such as paper. The sticking property against is further improved.
• a more preferable upper limit of the weight average molecular weight (Mw) is 950,000, and a further preferable upper limit is 900,000.
• the lower limit of the weight-average molecular weight (Mw) is not particularly limited, the preferred lower limit is 400,000, and the more preferred lower limit is 500,000, from the viewpoint of adhesive strength, shape retention property, etc. of the pressure-sensitive adhesive layer.
• the weight average molecular weight of the (meth)acrylic polymer can be determined, for example, by GPC (Gel Permeation Chromatography) in terms of standard polystyrene. More specifically, for example, using “2690 Separations Module” manufactured by Waters as a measuring instrument, "GPC KF-806L” manufactured by Showa Denko as a column, and ethyl acetate as a solvent, a sample flow rate of 1 mL/min, and a column temperature of 40°C. can be measured under the conditions of
• the pressure-sensitive adhesive layer may contain a tackifying resin.
• the tackifying resin include rosin ester-based resins, hydrogenated rosin-based resins, terpene-based resins, terpene phenol-based resins, coumarone-indene-based resins, alicyclic saturated hydrocarbon-based resins, C5-based petroleum resins, and C9-based resins. petroleum resins, C5-C9 copolymer petroleum resins, and the like. These tackifying resins may be used alone or in combination of two or more.
• the content of the tackifying resin is not particularly limited, it is preferable that the tackifying resin is not contained from the viewpoint of easier peeling without damaging the adherend during peeling (re-peeling).
• the preferred upper limit is 10 parts by weight with respect to 100 parts by weight of the resin (for example, (meth)acrylic polymer) that is the main component of the adhesive layer.
• the content of the tackifier resin is 10 parts by weight or less, the adherend can be easily peeled without damaging the adherend during peeling (re-peeling).
• the pressure-sensitive adhesive layer contains a cross-linking agent to form a cross-linked structure between the main chains of the resin (for example, the (meth)acrylic polymer, the tackifier resin, etc.) constituting the pressure-sensitive adhesive layer.
• 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.
• the (meth)acrylic polymer contains a structural unit derived from the hydroxyl group-containing monomer, the shear storage modulus of the pressure-sensitive adhesive layer at 23° C.
• the content of the cross-linking agent is preferably 0.01 to 10 parts by weight, preferably 0.1 to 7 parts by weight, relative to 100 parts by weight of the resin (for example, the (meth)acrylic polymer) that is the main component of the pressure-sensitive adhesive layer. Parts by weight are more preferred.
• the pressure-sensitive adhesive layer may further contain an inorganic filler such as fumed silica. By blending the inorganic filler, the cohesive force of the pressure-sensitive adhesive layer can be increased.
• the pressure-sensitive adhesive layer may further contain known additives such as plasticizers, resins, surfactants, waxes and fine particle fillers. These additives may be used alone, or two or more of them may be used in combination.
• the gel fraction of the pressure-sensitive adhesive layer is not particularly limited, but the preferred lower limit is 85% by weight and the preferred upper limit is 95% by weight.
• the preferred lower limit is 85% by weight or more
• the 180° adhesive strength of the pressure-sensitive adhesive layer is easily adjusted to the above range, and when peeling (re-peeling), the adherend is more easily peeled without damaging the adherend. be able to.
• the gel fraction is 95% by weight or less, the shear storage modulus of the pressure-sensitive adhesive layer at 23° C. and 1 Hz is easily adjusted to the above range, and the pressure-sensitive adhesive layer is attached to a non-smooth surface such as paper. Better adhesion.
• a more preferable lower limit of the gel fraction is 86% by weight, a more preferable upper limit is 94% by weight, a still more preferable lower limit is 87% by weight, and a further preferable upper limit is 93% by weight.
• the gel fraction of the adhesive layer can be measured by the following method. Only 0.1 g of the adhesive layer (adhesive composition) is taken out from the adhesive tape, immersed in 50 mL of ethyl acetate, and shaken with a shaker at 200 rpm and a temperature of 23° C. for 24 hours.
• a metal mesh (#200 mesh) is used to separate the ethyl acetate and the pressure-sensitive adhesive composition that has absorbed and swollen the ethyl acetate.
• the adhesive composition after separation is dried at 110° C. for 1 hour.
• the weight of the pressure-sensitive adhesive composition containing the metal mesh after drying is measured, and the gel fraction of the pressure-sensitive adhesive layer is calculated using the following formula.
• Gel fraction (% by weight) 100 x (W 1 - W 2 )/W 0 (W 0 : initial weight of adhesive composition, W 1 : weight of adhesive composition containing metal mesh after drying, W 2 : initial weight of metal mesh)
• the lower limit of the thickness of the pressure-sensitive adhesive layer is 30 ⁇ m.
• the shear storage modulus at 23° C. and 1 Hz of the pressure-sensitive adhesive layer and the 180° pressure-sensitive adhesive strength are adjusted within the above ranges, so that the pressure-sensitive adhesive tape has a certain thickness or more. While having an agent layer, it has excellent sticking property to non-smooth surfaces such as paper, and can be easily peeled off without damaging the adherend. In addition, when the thickness of the pressure-sensitive adhesive layer is reduced, the followability is deteriorated, so that the sticking property of the pressure-sensitive adhesive layer to the adherend may be deteriorated.
• a preferable lower limit of the thickness of the pressure-sensitive adhesive layer is 40 ⁇ m, and a more preferable lower limit is 50 ⁇ m.
• the upper limit of the thickness of the pressure-sensitive adhesive layer is not particularly limited, the upper limit is preferably 200 ⁇ m, more preferably 150 ⁇ m, from the viewpoint of the adhesive strength, shape retention property, etc. of the pressure-sensitive adhesive layer.
• the pressure-sensitive adhesive tape of the present invention may be a non-support type that does not have a substrate, but it is preferably a support type that has a substrate.
• the adhesive tape of the present invention may be a single-sided adhesive tape having an adhesive layer only on one side of the substrate, or a double-sided adhesive tape having an adhesive layer on both sides of the substrate. Although good, it is preferably a single-sided adhesive tape having an adhesive layer on only one side of the substrate.
• the substrate is not particularly limited, and examples of materials for the substrate include polyethylene terephthalate, polyethylene naphthalate, polyacetal, polyamide, polycarbonate, polyphenylene ether, polybutylene terephthalate, ultra-high molecular weight polyethylene, syndiotactic polystyrene, poly Arylate, polysulfone, polyethersulfone, polyphenylene sulfide, polyetheretherketone, polyimide, polyetherimide, fluororesin, liquid crystal polymer and the like.
• polyethylene terephthalate and polyethylene naphthalate are preferable because of their excellent heat resistance.
• the thickness of the base material is not particularly limited, but a preferable lower limit is 5 ⁇ m and a preferable upper limit is 188 ⁇ m. When the thickness of the base material is within the above range, the pressure-sensitive adhesive tape can have appropriate stiffness and excellent handleability.
• a more preferable lower limit of the thickness of the substrate is 12 ⁇ m, and a more preferable upper limit thereof is 125 ⁇ m.
• the pressure-sensitive adhesive tape of the present invention has a pressure-sensitive adhesive layer having a certain thickness or more by adjusting the shear storage modulus at 23° C. and 1 Hz and the 180° adhesive strength of the pressure-sensitive adhesive layer within the above ranges. While having such properties, it has excellent sticking property to non-smooth surfaces such as paper, and can be easily peeled off without damaging the adherend. As a method for adjusting the shear storage modulus at 23° C.
• the composition of the base polymer contained in the pressure-sensitive adhesive layer a method of adjusting the molecular weight (weight average molecular weight (Mw)) and the like, and a method of adjusting the degree of crosslinking (gel fraction) of the pressure-sensitive adhesive layer.
• the pressure-sensitive adhesive layer contains a (meth)acrylic polymer, and the (meth)acrylic polymer contains 40% by weight or more of structural units derived from the (meth)acrylic acid ester (a) described above, It is particularly preferable that the pressure-sensitive adhesive layer has a weight average molecular weight of 1,000,000 or less, a gel fraction of 85% by weight or more and 95% by weight or less, and a thickness of 30 ⁇ m or more.
• a pressure-sensitive adhesive tape having such a pressure-sensitive adhesive layer is also one aspect of the present invention. In such a pressure-sensitive adhesive tape of the present invention, the pressure-sensitive adhesive layer, the (meth)acrylic polymer, etc. are preferably the same as those described above.
• the shear storage modulus at is adjusted to the above range. That is, the pressure-sensitive adhesive layer preferably has a shear storage modulus of 1 ⁇ 10 4 Pa or more and 5 ⁇ 10 4 Pa or less at 23° C. and 1 Hz.
• the use of the pressure-sensitive adhesive tape of the present invention is not particularly limited.
• the adhesive tape which is excellent in the stickiness with respect to non-smooth surfaces, such as paper, and can be peeled easily, without damaging an adherend can be provided.
• Example 1 Preparation of (meth)acrylic polymer A reactor equipped with a thermometer, a stirrer and a condenser was charged with 52 parts by weight of ethyl acetate, and after the atmosphere was replaced with nitrogen, the reactor was heated to initiate reflux. After 30 minutes from the boiling of ethyl acetate, 0.08 part by weight of azobisisobutyronitrile was added as a polymerization initiator. To this, 47.2 parts by weight of 2-ethylhexyl acrylate, 47.5 parts by weight of lauryl acrylate, 5 parts by weight of 4-hydroxybutyl acrylate and 0.3 parts by weight of acrylic acid were added dropwise evenly and gradually over 1 hour and 30 minutes. reacted.
• a viscoelastic spectrometer manufactured by IT Keisoku & Co., Ltd., DVA-200 was used, and a temperature increase rate of 5 ° C./min in a simple temperature increase mode and a condition of 1 Hz- A dynamic viscoelastic spectrum was measured from 40 to 140°C.
• the storage elastic modulus at 23°C was defined as the shear storage elastic modulus at 23°C and 1 Hz of the pressure-sensitive adhesive layer.
• Examples 2 to 12, Comparative Examples 1 to 11 A pressure-sensitive adhesive tape was obtained in the same manner as in Example 1, except that the composition and weight average molecular weight of the (meth)acrylic polymer, and the amount of the cross-linking agent were changed as shown in Tables 1 and 2.
• the cross-linking agent Coronate HX (manufactured by Tosoh Corporation), which is an isocyanate-based cross-linking agent, and Tetrad C (manufactured by Mitsubishi Gas Chemical Company, Inc.), which is an epoxy-based cross-linking agent, were also used.
• Adhesiveness evaluation on non-smooth surfaces Adhesive tapes were attached to the paper surface of Campus Notebook (manufactured by Kokuyo Co., Ltd.) and Japanese paper (Ryuun pattern, manufactured by Kokuyo Co., Ltd.), and crimped by reciprocating a 2 kg roller once. . When only the adhesive tape part is grabbed and lifted, both the notebook paper and Japanese paper are lifted together with the adhesive tape. A case where neither the paper nor the Japanese paper was lifted and the adhesive tape was peeled off was evaluated as x.
• BA butyl acrylate 2-EHA: 2-ethylhexyl acrylate LA: lauryl acrylate LMA: lauryl methacrylate ISTA: isostearyl acrylate 4-HBA: 4-hydroxybutyl acrylate AAc: acrylic acid
• the adhesive tape which is excellent in the stickiness with respect to non-smooth surfaces, such as paper, and can be peeled easily, without damaging an adherend can be provided.

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• 2022
  • 2022-03-29 JP JP2022534685A patent/JPWO2022210638A1/ja active Pending
  • 2022-03-29 WO PCT/JP2022/015265 patent/WO2022210638A1/ja not_active Ceased
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