JP5596299B2 - Adhesive, adhesive sheet, and method for producing adhesive sheet - Google Patents

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 affixing for surface protection.

  The properties required for the pressure-sensitive adhesive sheet (surface protective sheet) require that the protective 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 when it is peeled off. 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 surface protection sheet does not have good adhesion with the α-olefin copolymer alone, and does not show any adhesion when used outdoors in winter. In practice, a styrene copolymer is added. There is a need to.

  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 aims at providing the adhesive sheet used for the surface protection use, and the manufacturing method of these 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 measured in a temperature range of 0 to 200 ° C. with a differential scanning calorimeter (DSC).
A crystalline propylene copolymer (A) having an endothermic peak of 1.1 to 24 J / g;
The main component is a mixture with an amorphous propylene copolymer (B) having no endothermic peak of 1 J / g or more.

  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, as a result of the study by the present inventors, the cohesive force, workability, and adhesiveness over time, which were problems of the pressure-sensitive adhesive containing the amorphous propylene copolymer, were satisfied, and the amorphous propylene copolymer was satisfied. In order to satisfy the initial adhesiveness and rough surface adhesiveness that are the characteristics of the polymer, by mixing a crystalline propylene-based copolymer having a crystal structure with good compatibility and excellent initial adhesiveness, The present inventors have found a pressure-sensitive adhesive that can be used for a pressure-sensitive adhesive sheet (surface protective sheet) that is excellent in cohesive strength and adhesiveness over time (stability) without impairing adhesive properties.

  In the pressure-sensitive adhesive of the present invention, the crystalline propylene copolymer (A) is a propylene copolymer containing propylene, an α-olefin having 4 to 12 carbon atoms, and ethylene as a copolymerization component. The amorphous propylene-based copolymer (B) is a propylene-based copolymer and / or propylene containing propylene and an α-olefin having 4 to 12 carbon atoms as a copolymerization component, and an α-olefin having 4 to 12 carbon atoms and A propylene-based copolymer containing ethylene as a copolymerization component is preferable. Since the propylene-based copolymer (A) having crystallinity has a network structure, it has an excellent balance between heat resistance and flexibility, and further includes an amorphous propylene-based copolymer (B). Since it has rubber elasticity, a surface protective sheet having the above characteristics can be obtained by using an adhesive layer containing these, which is effective. In addition, by mixing the crystalline propylene copolymer and the amorphous propylene copolymer, the cohesive force, workability, It is effective because it satisfies the adhesiveness and can satisfy the initial adhesiveness and rough surface adhesiveness which are the characteristics of the amorphous propylene copolymer.

  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.

  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 molecular weight of 1 having at least an aliphatic group having 8 to 30 carbon atoms. In the measurement in the temperature range of 0 to 200 ° C. with a differential scanning calorimeter (DSC), the pressure-sensitive adhesive layer includes a layer composed of 10,000 to 1,000,000 release agent and a polyolefin-based resin. The main component is a mixture of a crystalline propylene copolymer (A) having an endothermic peak of 24 J / g and an amorphous propylene copolymer (B) having no endothermic peak of 1 J / g or more. It is characterized by comprising an adhesive. As the pressure-sensitive adhesive sheet of the present invention, it is possible to obtain a pressure-sensitive adhesive sheet having a predetermined range of unwinding force by imparting a back treatment effect to the base material by containing a predetermined release agent and a polyolefin-based resin in the base material. Can and is useful.

  In the pressure-sensitive adhesive sheet of the present invention, the crystalline propylene-based copolymer (A) is a propylene-based copolymer containing propylene, an α-olefin having 4 to 12 carbon atoms, and ethylene as a copolymerization component. The propylene copolymer (B) is a propylene copolymer and / or propylene, a C 4-12 α-olefin, and ethylene containing propylene and a C 4-12 α-olefin as a copolymerization component. A propylene copolymer contained as a copolymerization component is preferred.

  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.

  The present invention relates to a method for producing a pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive sheet is formed by a coextrusion method.

  The crystalline propylene-based copolymer (A) has an endothermic peak of 1.1 to 24 J / g, as measured by a differential scanning calorimeter (DSC) in a temperature range of 0 to 200 ° C., preferably Is 3-20 J / g, more preferably 5-20 J / g endothermic peak. Since the copolymer (A) 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 lapse of time and is effective. . Moreover, when it exists in the said temperature range, adhesiveness and cohesion force enter into a desired range, and are effective.

  The crystalline propylene copolymer (A) has an endothermic peak of 1.1 to 24 J / g in the measurement in the temperature range of 0 ° C. to 200 ° C. with a differential scanning calorimeter (DSC). When the DSC analysis of the crystalline propylene copolymer is carried out by the method (conditions) shown in the examples, it is considered to be based on the melting of the crystal in the temperature range of 0 ° C. to 200 ° C. 1.1. It means that an endothermic peak of ˜24 J / g is confirmed.

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

  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, 4- Examples include methyl-pentene-1,4-methyl-hexene-1, and the like. However, the α-olefin of the present invention is not limited to the above compound. 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. Since the crystalline propylene-based copolymer (A) has a crystal structure, it is considered preferable to have an isotactic structure.

  Although the ratio of each component constituting the crystalline propylene copolymer (A) is not particularly limited, the pressure-sensitive adhesive of the present invention is used as a pressure-sensitive adhesive sheet (surface protective sheet). The propylene content in A) 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 copolymer (A) is preferably contained in the range of 5 to 15 mol%.

  The polymerization method of the crystalline propylene copolymer (A) 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 weight average molecular weight of the crystalline propylene copolymer (A) is not particularly limited, but the polystyrene equivalent weight average molecular weight (Mw) in the high temperature gel permeation chromatography (GPC) method is 1. About 1.0 × 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. is there. 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 (A) 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.

  The pressure-sensitive adhesive sheet (surface protective sheet) in which the pressure-sensitive adhesive of the present invention is used is mainly composed of a mixture of the crystalline propylene copolymer (A) and the amorphous propylene copolymer (B). A pressure-sensitive adhesive layer containing a propylene-based copolymer is provided. The proportion of the copolymer (A) in the entire mixed component of the copolymer (A) and the copolymer (B) is preferably 80 to 20% by weight, more preferably 70 to 30% by weight. Within the above range, it is effective from the viewpoint of initial adhesive strength and cohesive strength of the pressure-sensitive adhesive.

  The amorphous propylene-based copolymer (B) is an amorphous propylene-based copolymer that does not have an endothermic peak of 1 J / g or more in a temperature range of 0 to 200 ° C. with a differential scanning calorimeter (DSC). It is a copolymer (B), and preferably has no endothermic peak of 0.5 J / g or more. Since the amorphous propylene copolymer (B) does not have an endothermic peak of 1 J / g or more, the amorphous polypropylene copolymer does not have a crystal structure and has excellent initial adhesiveness. Is effective.

  The amorphous propylene-based copolymer (B) does not have an endothermic peak of 1 J / g or more as measured in a temperature range of 0 ° C. to 200 ° C. with a differential scanning calorimeter (DSC). Is 1 J / g or more that 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. This means that no endothermic peak is observed.

  The amorphous propylene-based copolymer (B) used for the base polymer of the pressure-sensitive adhesive of the present invention is a propylene-based copolymer and / or propylene containing propylene and an α-olefin having 4 to 12 carbon atoms as a copolymerization component. A propylene-based copolymer containing an α-olefin having 4 to 12 carbon atoms and ethylene as a copolymerization component is preferable.

  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, 4- Examples include methyl-pentene-1,4-methyl-hexene-1, and the like. However, the α-olefin of the present invention is not limited to the above compound. 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. Further, since the amorphous propylene copolymer (B) has an amorphous structure, it is considered preferable to have an atactic structure.

  The ratio of each component constituting the amorphous propylene-based copolymer (B) is not particularly limited, but the pressure-sensitive adhesive of the present invention is used as a pressure-sensitive adhesive sheet (surface protective sheet). The propylene content in the coalescence (B) 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 maintaining adhesiveness at low temperatures, the proportion of ethylene, which is a monomer component other than propylene, in the amorphous propylene copolymer (B) may be contained in the range of 3 to 15 mol%. preferable.

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

The weight average molecular weight of the amorphous propylene copolymer (B) is not particularly limited, but the polystyrene equivalent weight average molecular weight (Mw) in the high temperature gel permeation chromatography (GPC) method is as follows. 1.0 × 10 ^{5 to} 1.0 × 10 ⁶ , more preferably 1.5 × 10 ^{5 to} 8.0 × 10 ⁵ , and still more preferably about 2.0 × 10 ^{5 to} 8.0 × 10 ⁵ It is. When the weight average molecular weight is within the above range, it is favorable from the viewpoint of the solution viscosity at the time of coating and the workability at the time of extrusion.

  The JIS A hardness in JIS-K6301 of the amorphous propylene copolymer (B) is not particularly limited, but is preferably 20 to 65, more preferably 30 to 60, and still more preferably 40 to 55. Those having a JIS A hardness in the above range are soft and have good initial adhesiveness.

  The pressure-sensitive adhesive sheet (surface protective sheet) using the pressure-sensitive adhesive of the present invention is mainly composed of a mixture of the crystalline propylene copolymer (A) and the amorphous propylene copolymer (B). An adhesive layer containing a propylene-based copolymer is provided. The proportion of the copolymer (B) in the entire mixed component of the copolymer (A) and the copolymer (B) is preferably 20 to 80% by weight, more preferably 30 to 70% by weight. Within the above range, it is effective from the viewpoint of initial adhesive strength and cohesive strength of the pressure-sensitive adhesive.

  The pressure-sensitive adhesive used in the present invention is mainly composed of a propylene-based copolymer mixture of the crystalline propylene-based copolymer (A) and the amorphous propylene-based copolymer (B). It is preferably contained in an amount of 80% by weight or more, more preferably 90% by weight or more. In addition to the propylene-based copolymer mixture, in order to improve adhesiveness, the scope of the present invention is not impaired. Hydrogenated styrene-based ABA type block polymers such as styrene-ethylene-butylene copolymer-styrene (SEBS) and styrene-ethylene-propylene copolymer-styrene (SEPS), styrene-ethylene・ Hydrogenated styrene AB block polymers such as butylene copolymer (SEB) and styrene-ethylene / propylene copolymer (SEP) Hydrogenated styrene-based ABC type block polymer such as styrene-ethylene / butylene copolymer-olefin crystal block polymer (SEBC), olefin crystal-ethylene-butylene copolymer-olefin crystal block polymer (CEBC) Such a hydrogenated olefin type ABA type block polymer, a hydrogenated random copolymer composed of styrene and a diene hydrocarbon, and the like 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 increasing property, so that it is preferably 20% by weight or less, more preferably based on the whole pressure-sensitive adhesive. Is 10% by weight or less.

  In addition, the pressure-sensitive adhesive of the present invention includes, for example, an olefin polymer, a silicone-based polymer, an acrylic copolymer, a surfactant, a softening agent, a tackifier, and an aging agent for the purpose of controlling the adhesion characteristics. Inhibitors, hindered amine light stabilizers, ultraviolet absorbers, and other suitable additives such as fillers and pigments such as calcium oxide, magnesium oxide, silica, zinc oxide, and titanium oxide can be blended. 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, and 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 saponified 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. In addition, two or more ethylene / vinyl alcohol copolymers having different degrees of polymerization and vinyl alcohol structural unit contents may be used in combination.

  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 use such as being attached 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.

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

(Amorphous propylene copolymer)
Table 2 shows the composition ratio and characteristic values of the propylene-based copolymer used.

(Note) In Table 2, P: B: E represents propylene: butene-1: ethylene. The weight average molecular weight (Mw) was determined by the GPC method (column: manufactured by Tosoh Corporation, TSKgel SuperHZM-H / HZ4000 / HZ3000 / HZ2000, solvent: tetrahydrofuran (THF), polystyrene conversion), flow rate 0.6 ml / min, concentration 1 It is a value measured at 0.0 mg / ml and a column temperature of 140 ° C. Note that the melting peak temperature and the heat of fusion could not be confirmed.

  The differential scanning calorimeter (DSC) measurement uses a differential scanning calorimeter (device name DSC; DSC 6220 manufactured by SII Nano Technology), and the measurement conditions are temperature: 30 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.

<Example 1>
Propylene copolymer comprising 50% by weight of the crystalline propylene copolymer (1) in Table 1 and 50% by weight of the amorphous propylene copolymer (2) in Table 2 as the material for forming the pressure-sensitive adhesive layer Using the blended mixture, low density polyethylene (manufactured by Tosoh Corporation, Petrocene 172) was used as a base material layer forming material, and each was coextruded at a die temperature of 180 ° C. by an inflation molding method to obtain an adhesive sheet. The pressure-sensitive adhesive layer was adjusted to have a thickness of 10 μm and the base material layer had a thickness of 50 μm.

<Example 2>
Propylene copolymer comprising 80% by weight of the crystalline propylene copolymer (1) in Table 1 and 20% by weight of the amorphous propylene copolymer (2) in Table 2 as the material for forming the pressure-sensitive adhesive layer 10 parts by weight of a hydrogenated petroleum-based tackifier resin (Arakawa Chemical Co., Ltd., Alcon P-100) is mixed with 100 parts by weight of the blended mixture, and polypropylene (Nippon Polypro Co., Ltd.) is used as a base layer forming material. Manufactured by Novatec PP FY6C) and coextruded by a T-die molding method at a die temperature of 230 ° C. to obtain an adhesive sheet. 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>
Propylene copolymer comprising 40% by weight of the crystalline propylene copolymer (1) in Table 1 and 60% by weight of the amorphous propylene copolymer (2) in Table 2 as the material for forming the pressure-sensitive adhesive layer 10 parts by weight of a hydrogenated petroleum-based tackifier resin (Arakawa Chemical Co., Ltd., Alcon P-100) is mixed with 100 parts by weight of the blended mixture, and polypropylene (Nippon Polypro Co., Ltd.) is used as a base layer forming material. Manufactured by Novatec PP FY6C) and coextruded by a T-die molding method at a die temperature of 230 ° C. to obtain an adhesive sheet. 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.

<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 Industry 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. The 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, which is a 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, sterile filter). 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 . In addition, the calculation method of the impurity total content (weight%) contained in a mold release agent and the weight average molecular weight of a mold release agent is demonstrated 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, 50% by weight of the crystalline propylene copolymer (1) in Table 1 and 50% by weight of the amorphous propylene copolymer (2) in Table 2 were used. Consists of base material layers (A) and (B), uses low-density polyethylene (manufactured by Tosoh Corporation, Petrocene 172) as a forming material of the base material layer (A), and is on the side opposite to the adhesive layer. As a forming material of the base material layer (B) in contact with the material layer (A), 5 parts by weight of the above release agent is mixed with 100 parts by weight of low density polyethylene (Sumitomo Chemical Co., Sumikasen L-705). Each was coextruded by a blow molding method at a die temperature of 180 ° C. to obtain an adhesive sheet. 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 only the crystalline propylene copolymer (1) in Table 1 was used as the material for forming the pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer was adjusted to have a thickness of 10 μm and the base material layer had a thickness of 50 μm.

<Comparative example 2>
In Example 1, a pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that only the amorphous propylene copolymer (2) in Table 2 was used as the material for forming the pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer was adjusted to have a thickness of 10 μm and the base material layer had a thickness of 50 μm.

<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.

  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 3.

(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 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 50 ° C. for 30 days (N / 20 mm). 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 adhesive sheet was attached to a SUS304HL finished plate (Nisshin Steel Co., Ltd., DNA-SUS, SUS304HL finished) with a laminator (linear pressure 78.5 N / cm, speed 0.3 m / min), 23 The adhesive strength (N / 20 mm) after standing at 1 ° C. for 1 hour was measured. Measurement conditions: 23 ° C. × 65% RH, peeling rate 300 mm / min, 180 degree peel.

(Bending test in press brake)
In the bending test, a metal plate was placed on the lower mold (die) D2, and a predetermined bending position was performed using a bending mold made of an upper mold (punch) P2. At the time of bending, the adhesive sheet is attached to the surface of the metal plate in contact with the lower die (die) D2, and the SUS304HL plate (thickness 0.4mm) is bent five times by 90 ° to obtain the glue on the surface of the metal plate. The remaining property was confirmed. The pressure-sensitive adhesive having inferior cohesion tends to remain on the surface of the 304BA plate at the die shoulder contact portion, and this was used as an evaluation guideline for cohesion. The bending conditions were as follows: punch angle: 88 °, punch blade edge R: 0.2 mm, die V width: 12 mm, die angle: 88 °, die shoulder R: 1.5 mm.

(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 under each condition of low speed unwinding and 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.

(Note) In Table 3, rough surface adhesion (-) indicates that adhesion (fixation) was not possible 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 3, in Examples, the smooth surface and the rough surface have a small increase in adhesive strength over time with respect to initial adhesive strength, a stable adhesive strength over time, and cohesiveness at high temperatures. It was confirmed that it was excellent. On the other hand, in Comparative Example 1, it was not possible to measure the adhesive force on the rough surface, and in Comparative Example 2, it was confirmed that the cohesiveness was inferior to that of the Example. It was confirmed that the increase in the adhesive strength was large.

  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.

Claims (3)

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 has a crystalline propylene copolymer (A) having an endothermic peak of 1.1 to 24 J / g, as measured by a differential scanning calorimeter (DSC) in a temperature range of 0 to 200 ° C., An adhesive mainly composed of a mixture with an amorphous propylene copolymer (B) having no endothermic peak of 1 J / g or more,
The copolymer (A) is a propylene-based copolymer containing propylene, an α-olefin having 4 to 12 carbon atoms and ethylene as a copolymerization component,
The copolymer (B) is a copolymer of propylene-based copolymer and / or propylene, α-olefin having 4 to 12 carbon atoms, and ethylene containing propylene and α-olefin having 4 to 12 carbon atoms as a copolymerization component. A propylene-based copolymer containing as a component,
The polystyrene-converted weight average molecular weight (Mw) in the high temperature gel permeation chromatography (GPC) method of the copolymer (A) is 1.0 × 10 ^{5 to} 1.0 × 10 ⁶ ,
The polystyrene-converted weight average molecular weight (Mw) in the high temperature gel permeation chromatography (GPC) method of the copolymer (B) is 1.0 × 10 ^{5 to} 1.0 × 10 ⁶ ,
The ratio of the copolymer (B) in the entire mixed component of the copolymer (A) and the copolymer (B) is 20 to 70% by weight,
A pressure-sensitive adhesive sheet characterized by not passing through a stretching step. JIS Z0237 slow and fast rewind force at (2000) is, the pressure-sensitive adhesive sheet according to claim 1, wherein a is less than 1.0 N / 20 mm. The pressure-sensitive adhesive sheet according to claim 1 or 2 is formed by a coextrusion method.