JP2009275209A - Self-adhesive, self-adhesive sheet and method for producing the self-adhesive sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a self-adhesive with which occurrence of remaining adhesive and peeling failure can be prevented even with the elapse of time after the self-adhesive is subjected to outdoor exposure or storage at high temperature and which has good adhesive property, a self-adhesive sheet using the self-adhesive, a self-adhesive sheet used for a surface protection purpose, and a method for producing those self-adhesive sheets. <P>SOLUTION: The self-adhesive contains a crystalline propylene-based copolymer including, as copolymerization components, propylene, a 4-12C α-olefin and ethylene, wherein the propylene-based copolymer exhibits an endothermic peak of 1.1-24.0 J/g as measured with a differential scanning calorimeter (DSC) in a temperature range of 0-200°C. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pressure-sensitive adhesive, a pressure-sensitive adhesive sheet, and a method for producing the same. The pressure-sensitive adhesive sheet using the pressure-sensitive adhesive of the present invention is a metal plate, a coated metal plate, an aluminum sash, a resin plate, a decorative steel plate, a vinyl chloride laminated steel plate, a glass plate, an optical film, etc. It is useful as a pressure-sensitive adhesive sheet (including a pressure-sensitive adhesive sheet for surface protection, that is, a surface protective sheet) having a use such as being attached for surface protection.

  The properties required for the pressure-sensitive adhesive sheet (surface protective sheet) require that the pressure-sensitive adhesive sheet does not float or peel off after being attached to the adherend, and that the pressure-sensitive adhesive does not remain on the adherend during peeling and removal. In particular, when it is subjected to harsh conditions such as high temperature and outdoor exposure after being attached to the adherend and after peeling, a higher level of the above characteristics is also required.

  For this reason, as a pressure-sensitive adhesive that forms a pressure-sensitive adhesive layer of a pressure-sensitive adhesive sheet (surface protective sheet) that has been generally used, an acrylic copolymer is used as an isocyanate compound to such an extent that it does not lose its adhesiveness (stickiness). And those obtained by increasing the cohesion by cross-linking three-dimensionally with a methylol compound, or those obtained by blending a natural rubber or modified natural rubber with an appropriate amount of a tackifier or the like.

  The pressure-sensitive adhesive sheet (surface protective sheet) having such a pressure-sensitive adhesive layer is not particularly problematic for indoor use. However, when the pressure-sensitive adhesive is mainly composed of natural rubber or modified natural rubber, or in the case of a composition containing a tackifier or the like, the pressure-sensitive adhesive is constituted by a component having an unsaturated double bond. Therefore, when exposed to the outdoors, molecular breakage of the above components is caused by ultraviolet rays, and the adhesive may remain on the adherend when the adhesive sheet is peeled off. Therefore, an adhesive sheet with good weather resistance has been desired.

  In order to solve the above-mentioned problems, Patent Document 1 discloses a surface protective sheet excellent in weather resistance in which a pressure-sensitive adhesive layer is formed on a base film with a hydrogenated styrene copolymer. When the surface protective sheet using the pressure-sensitive adhesive layer containing the hydrogenated styrene copolymer is applied to an adherend such as a metal plate or a resin plate having a rough surface (rough surface). There is no problem, but it may cause problems such as peeling failure when pasted on a smooth metal plate, highly polar acrylic resin plate, polycarbonate resin plate, acrylic or polyester coated steel plate, etc. . Therefore, since it is necessary to use an additive that provides good peelability, there is a problem in that the contamination and adhesion over time are not stable.

  Moreover, in patent document 2 and patent document 3, the surface protection sheet which laminated | stacked the adhesive layer comprised from a C2-C12 alpha-olefin copolymer on the base film is disclosed, However, The said The surface protection sheet is not good in adhesion (tackiness) with the α-olefin copolymer alone, and does not show any adhesion when used outdoors in winter. It is necessary to add.

  Patent Document 4 discloses a surface protective sheet using a pressure-sensitive adhesive layer composed of an α-olefin copolymer and a styrene copolymer. However, in the said surface protection sheet, since a styrene-type copolymer is included in an adhesive, the peelability is not favorable and the problem which reduces workability | operativity has arisen.

  Furthermore, Patent Document 5 discloses a surface protective sheet having good adhesiveness using an α-olefin copolymer as an adhesive. However, since the α-olefin copolymer disclosed in the surface protective sheet is an amorphous α-olefin copolymer having no crystal part, the cohesive force is poor and adhesive residue is generated. Is causing problems. In order to improve the cohesive force, it is conceivable to increase the molecular weight of the pressure-sensitive adhesive component. On the other hand, when the solvent coating type is used, the solution viscosity increases or the surface protection sheet is produced by the coextrusion method. When it does, workability falls remarkably.

JP-A-6-1958 JP-A-7-233354 Japanese Patent Laid-Open No. 11-21519 JP-A-6-240215 JP 2002-302659 A

  Therefore, the present invention can prevent the occurrence of adhesive residue or peeling failure even after aging after outdoor exposure or storage at high temperature, and has a pressure-sensitive adhesive having good adhesiveness, a pressure-sensitive adhesive sheet using the pressure-sensitive adhesive, and the pressure-sensitive adhesive sheet. It is an object of the present invention to provide a pressure-sensitive adhesive sheet (surface protective sheet) used for surface protection and a method for producing these pressure-sensitive adhesive sheets.

  As a result of intensive studies to solve the above problems, the present inventors have found the pressure-sensitive adhesive shown below, and have completed the present invention.

  That is, the pressure-sensitive adhesive of the present invention is a pressure-sensitive adhesive comprising a crystalline propylene-based copolymer containing propylene, an α-olefin having 4 to 12 carbon atoms and ethylene as a copolymerization component. The polymer has an endothermic peak of 1.1 to 24.0 J / g as measured by a differential scanning calorimeter (DSC) in a temperature range of 0 to 200 ° C.

  In the pressure-sensitive adhesive sheet of the present invention, it is preferable that a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive is formed on at least one side of the substrate.

  The pressure-sensitive adhesive sheet of the present invention is preferably used for surface protection.

  Moreover, the pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer and one or more base materials, and the base material has a weight average of at least an aliphatic group having 8 to 30 carbon atoms. Crystalline propylene containing a release agent having a molecular weight of 10,000 to 1,000,000 and a layer made of polyolefin resin, wherein the pressure-sensitive adhesive layer contains propylene, an α-olefin having 4 to 12 carbon atoms and ethylene as a copolymerization component The propylene-based copolymer comprises 1.1 to 24.0 J / in a measurement in a temperature range of 0 to 200 ° C. with a differential scanning calorimeter (DSC). It is preferable to have an endothermic peak of g.

  The pressure-sensitive adhesive sheet of the present invention preferably has a low speed and / or a high speed rewinding force of 1.0 N / 20 mm or less in JIS Z0237 (2000).

  Moreover, this invention relates to the manufacturing method of the adhesive sheet currently formed by the coextrusion method.

  The inventors of the present invention have clarified that the peeling failure to the metal plate, the coated steel plate, etc. is due to the influence of the styrene block portion of the styrene type ABA block polymer. An α-olefin copolymer containing no benzene was studied. Furthermore, from the viewpoint of adhesiveness, it is necessary to copolymerize ethylene and an α-olefin component having 4 to 12 carbon atoms with respect to the propylene component, and from the viewpoint of low temperature adhesiveness, It was determined that the ingredients were necessary. However, when these polymerization components are polymerized, as disclosed in Patent Document 5, if it has an amorphous structure, the cohesive force is reduced, so as a pressure-sensitive adhesive having crystallinity, The crystalline propylene-based copolymer has been found.

  In addition, as the pressure-sensitive adhesive sheet of the present invention, a pressure-sensitive adhesive sheet having a predetermined range of unwinding force is obtained by providing a base material with a predetermined release agent and a polyolefin-based resin, thereby imparting a back treatment effect to the base material. Can be useful.

The figure which affixed the adhesive sheet of this invention on the SUS3048BA finishing board in the state which provided the bubble part and the collar part

  The propylene-based copolymer used for the base polymer of the pressure-sensitive adhesive of the present invention is a copolymer containing propylene, an α-olefin having 4 to 12 carbon atoms and ethylene as copolymerization components. The pressure-sensitive adhesive containing the copolymer exhibits good initial adhesion to a metal plate, a coated steel plate and the like.

  The propylene-based copolymer is a crystalline propylene-based copolymer. Since the copolymer has a crystal structure in the structure, an increase in the adhesion area due to the flow of the pressure-sensitive adhesive can be suppressed, and it has a good releasability even after aging and is effective.

  Specific examples of the α-olefin having 4 to 12 carbon atoms include butene-1, pentene-1, hexene-1, heptene-1, octene-1, nonene-1, decene-1, dodecene-1, and 4-methyl. -Pentene-1,4-methyl-hexene-1 and the like can be mentioned, but the α-olefin of the present invention is not limited to the above compounds. Among these, butene-1, hexene-1, octene-1, and 4-methyl-pentene-1 are preferable. These α-olefins having 4 to 12 carbon atoms can be used alone or in combination of two or more.

  The ratio of each component constituting the crystalline propylene-based copolymer is not particularly limited, but the pressure-sensitive adhesive of the present invention is used as a pressure-sensitive adhesive sheet (surface protective sheet), so that the propylene in the crystalline propylene-based copolymer is used. The content is preferably 60 to 95 mol%, more preferably 65 to 90 mol%, and particularly preferably 70 to 85 mol% in terms of the molar ratio of the monomer composition. From the viewpoint of low-temperature adhesiveness, the proportion of ethylene, which is a monomer component other than propylene, in the crystalline propylene-based copolymer is preferably contained in the range of 5 to 20 mol%.

  The polymerization method of the crystalline propylene copolymer is not particularly limited, and can be obtained by solution polymerization, slurry polymerization, and gas phase polymerization of the propylene, the α-olefin having 4 to 12 carbon atoms, and ethylene. More specifically, for example, the polymerization can be performed by a production method disclosed in JP-A No. 2003-321582.

  The pressure-sensitive adhesive used in the present invention contains the crystalline propylene copolymer as a main component, and usually contains the propylene copolymer in an amount of 80% by weight or more, more preferably 90% by weight or more. In addition to the propylene-based copolymer, styrene-ethylene-butylene copolymer-styrene (SEBS) and styrene-ethylene-propylene-based copolymer are used for the purpose of improving adhesiveness within a range not impairing the object of the present invention. Polymer-hydrogenated styrene type ABA type block polymer such as styrene (SEPS), styrene-ethylene-butylene copolymer (SEB) and styrene-ethylene-propylene copolymer (SEP) Of hydrogenated styrene type AB block polymer, styrene-ethylene-butylene copolymer-olefin crystal block polymer (SEBC) Hydrogenated olefin type A-B-C type block polymer, hydrogenated olefin type A-B-A type block polymer such as olefin crystal-ethylene-butylene copolymer-olefin crystal block polymer (CEBC), styrene and diene A hydrogenated random copolymer composed of a hydrocarbon can be added. These can be used alone or in combination of two or more. The use ratio of the block polymer having these styrene components can be determined as appropriate, but if the use ratio increases, it affects the adhesion enhancement property, so that it is 20% by weight or less with respect to the entire crystalline propylene copolymer. Is preferable, and more preferably 10% by weight or less.

  The crystalline propylene-based copolymer has an endothermic peak of 1.1 to 24.0 J / g as measured by a differential scanning calorimeter (DSC) in a temperature range of 0 to 200 ° C., preferably It has an endothermic peak of 3 to 20 J / g, more preferably 5 to 20 J / g. When it is within the above range, the adhesiveness and cohesive force are within the desired range and are effective.

  The crystalline propylene-based copolymer has an endothermic peak of 1.1 to 24.0 J / g as measured by a differential scanning calorimeter (DSC) in a temperature range of 0 ° C. to 200 ° C. Is considered to be based on melting of crystals in a temperature range of 0 ° C. to 200 ° C. when a DSC analysis of the crystalline propylene copolymer is performed by the method (conditions) shown in the examples. An endothermic peak of 24.0 J / g is confirmed.

The weight average molecular weight of the crystalline propylene-based copolymer is not particularly limited, but the polystyrene equivalent weight average molecular weight (Mw) in the high temperature gel permeation chromatography (GPC) method is 1.0 ×. It is about 10 ^{5 to} 1.0 × 10 ⁶ , more preferably about 1.5 × 10 ^{5 to} 8.0 × 10 ⁵ , and still more preferably about 2.0 × 10 ^{5 to} 8.0 × 10 ⁵ . When the weight average molecular weight is within the above range, the cohesive force is good, the adhesive can be peeled off satisfactorily, and the moldability when extruding a pressure-sensitive adhesive containing a propylene copolymer is also obtained. It is good.

  Moreover, the JIS A hardness in JIS-K6301 of the crystalline propylene copolymer is not particularly limited, but is preferably 50 to 100, more preferably 55 to 95, and still more preferably 60 to 90. Those having a JIS A hardness in the above range are soft and have good initial adhesiveness.

  In addition, the pressure-sensitive adhesive of the present invention may include, for example, an olefin polymer, a silicone-based polymer, an acrylic copolymer, a surfactant, a softening agent, and a tackifier for the purpose of controlling adhesive (tackiness) characteristics. Add appropriate additives such as additives and anti-aging agents, hindered amine light stabilizers, UV absorbers, and other fillers and pigments such as calcium oxide, magnesium oxide, silica, zinc oxide, and titanium oxide. it can. In addition, an appropriate surface modification treatment such as corona treatment or ultraviolet treatment can be applied to the surface of the pressure-sensitive adhesive layer for the purpose of controlling adhesiveness or preventing contamination.

  The blending of the softening agent is usually effective for improving the adhesive strength. As the softening agent, for example, low molecular weight polyisobutylene, hydrogenated polyisoprene, hydrogenated polybutadiene, liquid olefin polymer composed of propylene or α-olefin, and derivatives thereof can be used. The amount is preferably 0 to 40 parts by weight, more preferably 0 to 20 parts by weight, and particularly preferably 0 to 10 parts by weight with respect to 100 parts by weight of the crystalline propylene copolymer. If the blending amount exceeds 40 parts by weight, the adhesive residue at high temperature or outdoor exposure becomes remarkable.

  The molecular weight of the softening agent can be appropriately set, but the number average molecular weight is preferably about 5000 to 100,000, particularly preferably 10,000 to 50,000. If the molecular weight is 5,000 or less, it causes mass transfer to the adherend or heavy peeling, and if it is 100,000 or more, the effect of improving the adhesive strength is poor.

  On the other hand, the addition of tackifiers is usually effective in improving the adhesive strength, and the amount of the crystalline propylene-based co-polymer is from the viewpoint of improving the adhesive strength while avoiding the problem of adhesive residue due to the decrease in cohesive strength. The amount is preferably 50 parts by weight or less, more preferably 30 parts by weight or less, and particularly preferably 0 to 20 parts by weight with respect to 100 parts by weight of the polymer. Examples of the tackifier include petroleum resins such as aliphatic and aromatic, aliphatic / aromatic copolymer systems and alicyclic systems, coumarone indene resins, terpene resins, terpene phenol resins, and the like. Known adhesives such as polymerized rosin resins, (alkyl) phenol resins, xylene resins, or hydrogenated resins thereof are appropriately selected, and one or more of them can be used. A hydrogenated tackifier is preferred from the standpoint of peelability and weather resistance. A blend of a tackifier and an olefin resin is also commercially available, and these may be used.

  The thickness of the pressure-sensitive adhesive layer to be formed is appropriately determined according to the adhesive strength and the like. In general, the thickness is preferably 1 to 50 μm, more preferably 3 to 40 μm, and particularly preferably 5 to 35 μm. If necessary, the pressure-sensitive adhesive layer can be protected by temporarily attaching a separator or the like until it is put to practical use.

  The base material to which the pressure-sensitive adhesive layer is attached is not particularly limited. For example, a propylene-based polymer such as polyester, polyamide, a single system (homopolypropylene) or a block system, a random system, or a graft system having an ethylene component as a copolymerization component. Various types of plastic films, paper, metal using one or more of olefin polymers such as ethylene polymers such as low density, high density, linear low density, and ultra low density, and ethylene / propylene copolymers A film, a nonwoven fabric, etc. are used.

  In the case of using a plastic film for the base material (base material layer), for the purpose of preventing deterioration, for example, an antioxidant, an ultraviolet absorber, a light stabilizer such as a hindered amine light stabilizer or an antistatic agent, In addition, appropriate additives such as fillers and pigments such as carbon black, calcium oxide, magnesium oxide, silica, zinc oxide, and titanium oxide can also be blended.

  Among the above additives, from the viewpoint of improving weather resistance, an antioxidant, an ultraviolet absorber, a light stabilizer, a filler, and the like can be added to the base material (base material layer).

  As antioxidants, known antioxidants such as hindered phenol antioxidants, phosphorus processing heat stabilizers, lactone processing heat stabilizers, sulfur heat stabilizers can be used, and the blending ratio is , 5 parts by weight or less is preferable with respect to 100 parts by weight of the base resin of the base layer (in the case where the base layer is a blend, the blend is the base resin), more preferably 3 parts by weight or less. The amount is preferably about 0.1 to 0.5 parts by weight.

  As the ultraviolet absorber, a known ultraviolet absorber such as a benzotriazole-based ultraviolet absorber, a triazine-based ultraviolet absorber, or a benzophenone-based ultraviolet absorber can be used, and the blending ratio thereof is the base resin 100 that forms the base layer. 5 parts by weight or less is preferable with respect to parts by weight, more preferably 3 parts by weight or less, and still more preferably about 0.1 to 1 part by weight.

  As the light stabilizer, a known light stabilizer such as a hindered amine light stabilizer or a benzoate light stabilizer can be used, and preferably 5 parts by weight or less with respect to 100 parts by weight of the base resin of the base material layer. More preferably, it is 3 parts by weight or less, and more preferably about 0.1 to 1 part by weight.

  As the filler, an inorganic filler can be used, and carbon black, titanium oxide, zinc oxide and the like are preferably used. The blending ratio is preferably 20 parts by weight or less, more preferably 1 to 20 parts by weight, still more preferably about 5 to 15 parts by weight with respect to 100 parts by weight of the base resin of the base material layer. The additives such as the antioxidant and the inorganic filler can be used in combination.

  In addition to the above base material, the base material used in the pressure-sensitive adhesive sheet of the present invention is composed of one or more base materials (layers), and has a weight average molecular weight of 10,000 to at least having an aliphatic group having 8 to 30 carbon atoms. 1 million release agent and a layer made of polyolefin resin.

  When the substrate is composed of a plurality of substrates (layers), all the substrates may contain the release agent, and only a part of the substrates (layers) A release agent may be included, that is, a base material (layer) that does not include a release agent may be included. Furthermore, you may use the base material containing the mold release agent only in the outermost layer on the opposite side to an adhesive layer. Thus, when a base material contains a mold release agent, a back surface treatment effect can be imparted to the base material, which is effective.

  The release agent is a release agent having an aliphatic group having 8 to 30 carbon atoms in the polymer side chain and having a weight average molecular weight of 10,000 to 1,000,000. Specifically, the release agent is completely saponified or partially saponified. Examples of the reaction product include a compound having an aliphatic group having 8 to 30 carbon atoms, an isocyanate reaction, an ester reaction, and the like on an ethylene / vinyl alcohol copolymer or polyvinyl alcohol.

  The release agent was synthesized by subjecting a fully or partially saponified ethylene / vinyl alcohol copolymer or polyvinyl alcohol to an isocyanate reaction using octyl isocyanate, decyl isocyanate, lauryl isocyanate, stearyl isocyanate, or the like. Or can be easily synthesized by an ester reaction using lauric acid or stearic acid. In particular, from the viewpoint of compatibility with a polyolefin resin (olefin polymer), a reaction product composed of an ethylene / vinyl alcohol copolymer and an isocyanate compound is considered to be more preferable.

  The structure of the ethylene-vinyl alcohol copolymer is not particularly limited, but the content of vinyl alcohol structural units is preferably 40 to 80 mol%, more preferably 40 to 70 mol%. When the content of the vinyl alcohol structural unit in the ethylene-vinyl alcohol copolymer is less than 40 mol%, the reaction product obtained by using this exhibits sufficient release performance for use as a release agent. On the other hand, when it exceeds 80 mol%, when the reaction product obtained using this is used as a release agent, the compatibility with other resins is poor, and as a result, good release performance. May not be shown. The ethylene-vinyl alcohol copolymer may be used by mixing two or more types having different degrees of polymerization and vinyl alcohol structural units.

  Moreover, as said isocyanate compound, it is preferable to use stearyl isocyanate from a peelable and heat resistant viewpoint.

  Furthermore, by-products and reaction residues generated during the reaction cause contamination of the adherend, deterioration of adhesion, line contamination during production, smoke generation, etc., and therefore must be reduced as much as possible. Specifically, the polystyrene-reduced weight average molecular weight in GPC analysis is preferably such that the amount of by-products and reaction residues is 1.0 area% or less with respect to the release agent, more preferably 0.6 area%. The following are considered.

  The polyolefin resin preferably contains a homopolymer of an olefin monomer and / or a copolymer of an olefin monomer and a polar monomer. More specifically, examples of the homopolymer include homopolypropylene, and examples of the copolymer include propylene-based polymers such as block systems, random systems, and graft systems using an ethylene component as a copolymer component, and reactor TPO. , Ethylene polymers such as low density, high density, linear low density, and ultra low density, ethylene / propylene copolymer, ethylene / vinyl acetate copolymer, ethylene / methyl acrylate copolymer, ethylene / ethyl acrylate copolymer Examples thereof include a polymer, an ethylene / butyl acrylate copolymer, an ethylene / methacrylic acid copolymer, and an ethylene / methyl methacrylate copolymer, and it is preferable to contain one or more of these.

  The content ratio of the release agent contained in the base material is preferably 0.1 to 20 parts by weight of the release agent with respect to 100 parts by weight in total of the polyolefin resin and the release agent constituting the base material. 0.5 to 20 parts by weight is more preferable. When the ratio of the release agent is less than 0.1 parts by weight, the release performance is not sufficiently exhibited. On the other hand, when it exceeds 20 parts by weight, the performance is saturated, which is economically disadvantageous. In addition, the compatibility with the polyolefin-based resin decreases due to an increase in the release agent, which is not preferable because molding processability is decreased.

  As the ultraviolet transmittance of the substrate to which the pressure-sensitive adhesive layer is attached, the transmittance at a wavelength of 365 nm is preferably 5% or less, particularly preferably 1% or less.

  As thickness of the said base material (base material layer), it is about 5-300 micrometers, Preferably it is 20-150 micrometers, However, It is not limited to this.

  The pressure-sensitive adhesive layer can be formed, for example, by a method of applying a solution of a pressure-sensitive adhesive or a hot melt to a substrate, a method of transferring a pressure-sensitive adhesive layer applied and formed in accordance with a separator, or a method of forming a pressure-sensitive adhesive layer. A method of extruding and coating a material on a substrate, a method of extruding a substrate and an adhesive layer in two or multiple layers, a method of laminating an adhesive layer on a substrate or a laminate layer and an adhesive layer It can be performed in accordance with a known method for producing a pressure-sensitive adhesive sheet, such as a method of laminating two layers, a method of laminating a pressure-sensitive adhesive layer and a base material forming material such as a film or a laminate layer in two layers or multilayers. Among these methods for producing pressure-sensitive adhesive sheets, a method of co-extrusion molding of a pressure-sensitive adhesive layer together with a base material layer made of a thermoplastic resin by a two-layer or multi-layer method by an inflation method or a T-die method is from the viewpoint of productivity and cost. It can be preferably used.

  For the purpose of forming a wound body that can be easily rewound, for example, a fatty acid amide or polyethyleneimine is applied to the surface of the base material (base material layer) that is not provided with an adhesive layer. It can also be added for release treatment, or a coating layer made of an appropriate release agent such as silicone, long chain alkyl, or fluorine can be provided.

  The pressure-sensitive adhesive sheet of the present invention preferably has a low speed and a high speed rewinding force of JIS Z0237 (2000) of 1.0 N / 20 mm or less. Here, the low speed in the present invention means a rewind speed of 0.3 m / min, and the high speed means a rewind speed of 30 m / min. Moreover, the pressure-sensitive adhesive sheet of the present invention comprises a wound body obtained by winding a pressure-sensitive adhesive sheet (pressure-sensitive adhesive tape) into a roll, and a rewind speed of 0.3 m / min (low-speed rewind) and 30 m / min (high-speed rewind). Thus, the rewinding force when rewinding is more preferably 0.7 N / 20 mm or less at any rewinding speed. When the unwinding force exceeds 1.0 N / 20 mm, the adhesive sheet (adhesive tape) tends to tear when the adhesive sheet (adhesive tape) is rewound. In the present invention, the pressure-sensitive adhesive sheet (pressure-sensitive adhesive tape) in which the cut is formed on the base material by setting the rewinding force from the low-speed range to the high-speed range of the pressure-sensitive adhesive sheet (pressure-sensitive adhesive tape) wound body within the above range. It becomes possible to effectively prevent the tearing phenomenon at the time, and to maintain the workability at the time of attachment. In the present invention, the unwinding force of the pressure-sensitive adhesive sheet can be adjusted by the type and thickness of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer, the type and blending amount of the release agent constituting the base material (layer), and the like.

  In addition, the rewinding force of the pressure-sensitive adhesive sheet in the present invention is based on JIS Z0237 (2000). A pressure-sensitive adhesive sheet having a width of 20 mm wound in a roll shape is used as a test sample. In use, it is measured under conditions of a rewind speed of 0.3 m / min (low speed rewind) and 30 m / min (high speed rewind). The rewinding force in the present invention refers to the maximum value of the rewinding force measured as described above.

  The pressure-sensitive adhesive sheet of the present invention can be preferably used for applications requiring removability and temporary sticking properties, and in particular, a metal plate, a coated metal plate, an aluminum sash, a resin plate, a decorative steel plate, a vinyl chloride laminated steel plate, When transporting, processing, and curing a glass plate or the like, it can be suitably used as a pressure-sensitive adhesive sheet (surface protective sheet) that has a purpose of being applied for surface protection.

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples of the present invention, but the present invention is not limited to these examples.

(Crystalline propylene copolymer)
Table 1 shows the composition ratio and characteristic values of the propylene-based copolymer used.

  The differential scanning calorimeter (DSC) measurement uses a differential scanning calorimeter (device name DSC; DSC 6220 manufactured by SII Nanotechnology Co., Ltd.) as measurement conditions: temperature: 0 to 200 ° C., atmospheric gas: nitrogen (200 ml / min), Temperature rising rate: measured at 10 ° C./min. The temperature raising and lowering process during the measurement was performed at 10 ° C./min. The melting peak temperature and the heat of fusion (melting peak area) were calculated according to JIS K7122.

(注)表１中、Ｐ：Ｂ：Ｅはプロピレン：ブテン−１：エチレンを示す。なお、重量平均分子量（Ｍｗ）は、高温ＧＰＣ法（カラム：東ソー製、ＴＳＫｇｅｌ ＧＭＨＨＲ−Ｈ（２０）×３、溶媒：１，２，４−トリクロロベンゼン、ポリスチレン換算）により、流量１．０ｍｌ／分、濃度１．０ｍｇ／ｍｌ、カラム温度１４０℃にて、測定した値である。

(Note) In Table 1, P: B: E represents propylene: butene-1: ethylene. The weight average molecular weight (Mw) was determined by a high temperature GPC method (column: manufactured by Tosoh Corporation, TSKgel GMHHR-H (20) × 3, solvent: 1,2,4-trichlorobenzene, converted to polystyrene) at a flow rate of 1.0 ml / It is a value measured at a minute, a concentration of 1.0 mg / ml, and a column temperature of 140 ° C.

<Example 1>
The crystalline propylene copolymer (1) in Table 1 is used as the material for forming the pressure-sensitive adhesive layer, and low-density polyethylene (Tosoh Corp., Petrocene 172) is used as the material for forming the base material layer. By co-extrusion at a die temperature of 180 ° C. by a molding method, an adhesive sheet was obtained. The pressure-sensitive adhesive layer was adjusted to have a thickness of 6 μm and the base material layer had a thickness of 50 μm.

<Example 2>
The crystalline propylene-based copolymer (2) in Table 1 is used as the material for forming the pressure-sensitive adhesive layer, and polypropylene (Novatech PP FY6C, manufactured by Nippon Polypro Co., Ltd.) is used as the material for forming the base material layer. By co-extrusion at a die temperature of 220 ° C. by a molding method, an adhesive sheet was obtained. The thickness of the pressure-sensitive adhesive layer was adjusted to 10 μm, and the thickness of the base material layer was adjusted to 40 μm.

<Example 3>
As the material for forming the pressure-sensitive adhesive layer, the crystalline propylene copolymer (3) in Table 1 is used, and hydrogenated petroleum-based tackifier resin (100 parts by weight) with respect to 100 parts by weight of the crystalline propylene copolymer (3). Arakawa Chemical Co., Ltd., Alcon P-100) was adjusted according to Example 1 except that 10 parts by weight was used. The pressure-sensitive adhesive layer was adjusted to have a thickness of 6 μm and the base material layer had a thickness of 50 μm.

<Example 4>
First, a release agent was prepared by the following method.

The release agent is composed of 100 parts by weight of an ethylene-vinyl alcohol copolymer (Kuraray Co., Eval E-171B, ethylene structural unit: 44 mol%) and octadecyl isocyanate (Hodogaya Chemical Co., Millionate O) 310. Part by weight was dispersed in 2000 parts by weight of toluene, and water was separated and removed from the refluxing apparatus while refluxing for 2 hours. Thereafter, the mixture was cooled to 40 ° C., 300 parts by weight of dimethyl sulfoxide was added, and octadecyl isocyanate (Hodogaya Chemical Co., Ltd.) was adjusted so that the equivalent ratio of isocyanate groups to hydroxyl groups of the ethylene-vinyl alcohol copolymer was 0.7 equivalents. Product name, “Millionate O”) was added dropwise with stirring, and reacted at 120 ° C. for 4 hours. During this time, the residual isocyanate group in the system was quantified with an infrared spectrophotometer (around 2260 cm ⁻¹ ), and the end point was defined as the end point of the residual content.

  After completion of the reaction, 340 parts by weight of water was added to the reaction solution to separate the reaction solution. The reaction solution as the toluene layer was azeotropically dehydrated at 110 ° C. for 1 hour, and then the reaction solution was subjected to pressure filtration at 30 ° C. using a sealed pressure filter (manufactured by Toyo Seisakusho, Ltd.). The obtained filtrate was poured into 5000 parts by weight of methanol to precipitate a white precipitate. The precipitate was separated by filtration, washed with methanol, centrifuged, and dried and pulverized to obtain 363 parts by weight of the desired release agent.

The total content of impurities contained in the release agent was 0.4% by weight, and the weight average molecular weight was 1.13 × 10 ⁵ . A method for calculating the total content (% by weight) of impurities contained in the release agent and the weight average molecular weight of the release agent will be described in detail below.

The total content of impurities contained in the release agent was evaluated using the GPC method. The apparatus is “TSKgel” manufactured by Tosoh Corporation (solvent: tetrahydrofuran, temperature: 40 ° C., flow rate: 0.6 ml / min, concentration: 1.0 mg / ml, column: SuperHZM-H / HZ4000 / HZ3000 / HZ2000, detector: RI ( In the obtained molecular weight distribution diagram, the percentage of the peak area of the component below the peak valley (minimum value) having a polystyrene equivalent molecular weight of about 3.0 × 10 ^{3 with} respect to the total peak area is expressed as a percentage. The expressed value was used.

The weight average molecular weight of the release agent is a peak valley having a polystyrene equivalent molecular weight of about 3.0 × 10 ³ in a molecular weight distribution diagram obtained in the same manner as the total content of impurities contained in the release agent. It is the weight average molecular weight for the high molecular weight component rather than (minimum value).

  As the material for forming the pressure-sensitive adhesive layer, the crystalline propylene-based copolymer (1) in Table 1 is used, and the base material layer is composed of the base material layers (A) and (B). As the forming material, low-density polyethylene (Tosoh Corp., Petrocene 172) is used, and as the forming material of the base material layer (B) on the side opposite to the adhesive layer and in contact with the base material layer (A), low-density polyethylene ( Sumitomo Chemical Co., Ltd., SUMIKACEN L-705) 100 parts by weight were mixed with 5 parts by weight of the above mold release agent, and each was coextruded at a die temperature of 180 ° C. by an inflation molding method. Obtained. The pressure-sensitive adhesive layer was adjusted to have a thickness of 6 μm, a base material layer (A) having a thickness of 45 μm, and a base material layer (B) having a thickness of 5 μm.

<Example 5>
As a forming material for the base material layer (B), 10 parts by weight of polypropylene (manufactured by Nippon Polypro Co., Ltd., Wintech WFX4T) with respect to 100 parts by weight of low density polyethylene (Sumitomo Chemical Co., Ltd., Sumikasen L-705), the above examples A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 4 except that 7 parts by weight of the release agent used in 4 was mixed. The pressure-sensitive adhesive layer was adjusted to have a thickness of 6 μm, a base material layer (A) having a thickness of 45 μm, and a base material layer (B) having a thickness of 5 μm.

<Comparative Example 1>
In Example 1, a pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that an ethylene / octene binary copolymer (manufactured by DuPont, Affinity PF-1140) was used as the material for forming the pressure-sensitive adhesive layer. . The ethylene / octene binary copolymer used as a material for forming the pressure-sensitive adhesive layer had an endothermic peak of 95.7 ° C. (40.5 J / g) under the measurement conditions. The pressure-sensitive adhesive layer was adjusted to have a thickness of 6 μm and the base material layer had a thickness of 50 μm.

<Comparative Example 2>
Except for using an amorphous ethylene / propylene / butene terpolymer (P: E: B = 80: 6: 14, Mw = 5.7 × 10 ⁵ ) as a material for forming the pressure-sensitive adhesive layer, A pressure-sensitive adhesive sheet was obtained in the same manner as Example 1. The thickness of the pressure-sensitive adhesive layer was adjusted to 6 μm, and the thickness of the base material layer was adjusted to 50 μm. The amorphous ethylene / propylene / butene terpolymer used as the material for forming the pressure-sensitive adhesive layer did not exhibit an endothermic peak under the measurement conditions.

<Comparative Example 3>
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that SEBS (Asahi Kasei Co., Ltd., Tuftec H1221) was used as the pressure-sensitive adhesive. The thickness of the pressure-sensitive adhesive layer was adjusted to 10 μm, and the thickness of the base material layer was adjusted to 50 μm. The SEBS used as a pressure-sensitive adhesive forming material did not show an endothermic peak under the measurement conditions.

<Comparative example 4>
As a material for forming the pressure-sensitive adhesive layer, hydrogenated petroleum-based tackifier resin (Arakawa Chemical Co., Ltd., Alcon P-) is used with respect to 100 parts by weight of a propylene / α-olefin binary copolymer (manufactured by Mitsui Chemicals, Tuffmer XR107L). 100) Adjustment was made according to Example 2, except that 10 parts by weight were used. The pressure-sensitive adhesive layer was adjusted to have a thickness of 10 μm and the base material layer had a thickness of 60 μm. The propylene / α-olefin binary copolymer used as a material for forming the pressure-sensitive adhesive layer had an endothermic peak of 108.3 ° C. (24.1 J / g) under the measurement conditions.

<Comparative Example 5>
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 2 except that 60 parts by weight of hydrogenated petroleum-based tackifying resin was used. The pressure-sensitive adhesive layer was adjusted to have a thickness of 6 μm and the base material layer had a thickness of 50 μm.

  The following evaluation was performed about the adhesive sheet (surface protection sheet) obtained by the Example and the comparative example. The evaluation results are shown in Table 2.

(Initial adhesive strength)
The obtained adhesive sheet was attached to a SUS304BA finish plate (Nisshin Steel Co., Ltd., DNA-SUS, SUS304BA finish) by two reciprocating pressure bonding with a 2 kg roller, and then the adhesive strength after standing at 23 ° C. for 1 hour (N / 20 mm). Measurement conditions: 23 ° C. × 65% RH, peeling rate 300 mm / min, 180 degree peel.

(Adhesive strength over time)
The obtained pressure-sensitive adhesive sheet was affixed to a SUS304BA finished plate by two reciprocating pressure bonding with a 2 kg roller, and then the adhesive strength (N / 20 mm) after being left at 50 ° C. for 30 days was measured. Measurement conditions: 23 ° C. × 65% RH, peeling rate 300 mm / min, 180 degree peel.

(Adhesion increase rate)
Adhesion increase rate (%) = 100 × (long-lasting adhesive force−initial adhesive force) / (initial adhesive force)

(Rough surface adhesion)
After the obtained pressure-sensitive adhesive sheet was attached to a SUS304HL finished plate (Nisshin Steel Co., Ltd., DNA-SUS, SUS304HL finished) by two reciprocating pressure bonding with a 2 kg roller, the adhesive strength after standing at 23 ° C. for 1 hour (N / 20 mm). Measurement conditions: 23 ° C. × 65% RH, peeling rate 300 mm / min, 180 degree peel.

(Cohesive strength test)
As shown in FIG. 1, the obtained pressure-sensitive adhesive sheet was pasted on a SUS304BA finished plate in a state where air bubbles and heels were provided, and allowed to stand at 80 ° C. for 30 days. The adhesive residue was visually confirmed. Those in which adhesive residue was confirmed were determined as cohesion force x, and those in which no adhesive residue was confirmed were determined as cohesion force o.

(Rewind force)
Based on JIS Z0237 (2000), an adhesive sheet with a width of 20 mm wound in a roll shape was used as a test sample, and a rewinding speed of 0.3 m / min (at a measurement atmosphere temperature of 23 ° C.) was used. The unwinding force (N / 20 mm) under each condition of 30 m / min (high speed unwinding) was measured. Note that the maximum value of the output unwinding force was the unwinding force. Moreover, it was confirmed whether the adhesive sheet was not torn during the rewinding of the adhesive sheet.

(注)表２中の粗面接着力における（−）は接着力不足のため、接着（固定）されなかったことを示す。また、巻戻し力の空欄部分、及び、実施例４及び５の空欄部分については、評価していないことを示す。

(Note) The rough surface adhesion (-) in Table 2 indicates that the adhesive was not bonded (fixed) due to insufficient adhesion. Moreover, it has shown that it is not evaluating about the blank part of unwinding force, and the blank part of Example 4 and 5. FIG.

  From Table 2, it can be confirmed that in the examples, the increase in the adhesive strength at high temperatures with respect to the initial adhesive strength is small, the adhesive strength is stable with time, and the cohesiveness at high temperatures is excellent. It was.

  Moreover, in Examples 4 and 5, it is composed of a plurality of base materials, and by containing a predetermined release agent and polyolefin resin in the outermost layer of the base material, a back treatment effect is imparted, and a predetermined range of rewinding is performed. It was confirmed that power was obtained.

A: Bubble part B: Gutter part C: SUS304BA finish board PSAS: Adhesive sheet (surface protection sheet)

Claims (7)

A pressure-sensitive adhesive comprising a crystalline propylene-based copolymer containing propylene, an α-olefin having 4 to 12 carbon atoms and ethylene as a copolymerization component,
The pressure-sensitive adhesive, wherein the propylene-based copolymer has an endothermic peak of 1.1 to 24.0 J / g as measured by a differential scanning calorimeter (DSC) in a temperature range of 0 to 200 ° C.   A pressure-sensitive adhesive sheet, wherein the pressure-sensitive adhesive layer made of the pressure-sensitive adhesive according to claim 1 is formed on at least one side of a substrate.   The pressure-sensitive adhesive sheet according to claim 2, which is used for surface protection.   The pressure-sensitive adhesive sheet according to claim 2 or 3 is formed by a co-extrusion method. An adhesive sheet comprising an adhesive layer and one or more base materials,
The base material includes at least a release agent having a weight average molecular weight of 10,000 to 1,000,000 having an aliphatic group having 8 to 30 carbon atoms, and a layer made of a polyolefin resin,
The pressure-sensitive adhesive layer comprises a pressure-sensitive adhesive containing a crystalline propylene-based copolymer containing propylene, an α-olefin having 4 to 12 carbon atoms and ethylene as a copolymerization component,
The pressure-sensitive adhesive sheet, wherein the propylene-based copolymer has an endothermic peak of 1.1 to 24.0 J / g as measured by a differential scanning calorimeter (DSC) in a temperature range of 0 to 200 ° C.   The pressure-sensitive adhesive sheet according to claim 5, wherein the low-speed and high-speed rewinding force in JIS Z0237 (2000) is 1.0 N / 20 mm or less.   The pressure-sensitive adhesive sheet according to claim 5 or 6 is formed by a coextrusion method.

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