JP2009249540A - Adhesive composition and adhesive tapes - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive composition which is excellent in initial adhesive force, little changes adhesive force with the passage of time, hardly stains the surface of an adherend after peeled from the adherend, or the like, contains an acrylic block copolymer (A) as a main component, and can form an adhesive layer, and to provide an adhesive tape using the adhesive composition. <P>SOLUTION: The adhesive composition is obtained by adding a blocking-preventing agent having compatibility with an adhesive polymer and solid at ordinary temperature from the outside. The adhesive tape uses the adhesive composition. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pressure-sensitive adhesive composition mainly composed of an acrylic block copolymer used for constituting a pressure-sensitive adhesive layer on a film substrate or the like, and a pressure-sensitive adhesive tape using the pressure-sensitive adhesive composition.

  Conventionally, acrylic or rubber-based adhesives have been generally used as adhesives, but in recent years, adhesives mainly composed of styrene-conjugated diene block copolymers have been developed. Such a pressure-sensitive adhesive containing a block copolymer as a main component is excellent in terms of drying efficiency and safety as compared with an emulsion-based or solvent-based pressure-sensitive adhesive, and has attracted particular attention. However, the styrene-conjugated diene block copolymer has a problem that it has low weather resistance and light resistance.

  On the other hand, in recent years, an acrylic block copolymer composed of a methacrylic polymer block and an acrylic polymer block synthesized by living polymerization has been proposed (Patent Document 1). Such acrylic block copolymers have the characteristics of maintaining high weather resistance, light resistance, and transparency inherent in acrylic polymers, while having excellent structure control and narrow molecular weight distribution derived from living polymerization. Have. Moreover, various characteristics can be exhibited by appropriately selecting the monomer constituting each polymer block, and development to various uses as an adhesive is expected (Patent Documents 2 and 3).

  By the way, the pressure-sensitive adhesive composition is usually handled in the form of pellets or blocks. However, since the self-adhesive property (self-blocking property) is high, the pressure-sensitive adhesive tape is formed by forming a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition. In manufacturing, there was a problem that handling property was very bad. Therefore, in order to suppress self-blocking of the pressure-sensitive adhesive composition, an anti-blocking agent that is incompatible with the pressure-sensitive adhesive composition may be blended in the pressure-sensitive adhesive composition.

However, when an anti-blocking agent that is incompatible with the pressure-sensitive adhesive composition is blended in the pressure-sensitive adhesive composition, the pressure-sensitive adhesive tape having the pressure-sensitive adhesive layer composed of the pressure-sensitive adhesive composition is subjected to high temperature and high humidity conditions. The antiblocking agent sometimes bleeded out. In this case, the adhesive strength may fluctuate with time, or the adherend may be contaminated after the surface protective film is peeled off from the adherend such as a coated steel plate. In order to solve such a problem, it is effective to add an antiblocking agent having compatibility to the hard segment in a styrene or olefin block copolymer (Patent Document 4).
Patent No. 3040172 JP 2003-105300 A JP 2001-348553 A JP2007-1265669A

  However, Patent Document 4 does not mention a pressure-sensitive adhesive composition mainly composed of an acrylic block copolymer composed of a methacrylic polymer block and an acrylic polymer block. At present, it is not sufficiently known whether the agent can be used effectively.

  An object of the present invention is an acrylic resin that has excellent initial adhesive strength, little fluctuation in adhesive strength over time, and contamination of the adherend surface after peeling from the adherend is less likely in view of the current state of the prior art described above. It is providing the adhesive which can comprise the adhesive layer which has a system block copolymer (A) as a main component, and the adhesive tapes using this adhesive.

  As a result of intensive studies to solve the above problems, the present inventor has found a pressure-sensitive adhesive composition in which a solid anti-blocking agent is added externally at room temperature compatible with the pressure-sensitive adhesive polymer, and completes the invention. It came to do.

  That is, the present invention provides an adhesive composition mainly composed of an acrylic block copolymer (A) comprising a methacrylic polymer block (a) and an acrylic polymer block (b), and prevents blocking of solids at room temperature. It is an adhesive composition by which an agent is added, Comprising: It is related with the adhesive composition characterized by the said antiblocking agent having compatibility with the said adhesive polymer.

As a preferred embodiment,
The acrylic block copolymer (A) comprises a methacrylic polymer block (a) and an acrylic polymer block (b), and at least one polymer block has a carboxyl group and / or an acid anhydride group. The above-mentioned pressure-sensitive adhesive composition, which is an acrylic block copolymer (A) having,
The above-mentioned pressure-sensitive adhesive composition, wherein the acrylic block copolymer (A) has a carboxyl group and / or an acid anhydride group in the acrylic polymer block (b),
In the acrylic block copolymer (A), the proportion of the methacrylic polymer block (a) is 10 to 50% by weight,
The above-mentioned pressure-sensitive adhesive composition, wherein the acrylic block copolymer (A) is a diblock copolymer or a triblock copolymer, or a mixture thereof,
The above pressure-sensitive adhesive composition, wherein the acrylic block copolymer (A) has a number average molecular weight (Mn) of 30,000 to 300,000,
The above pressure-sensitive adhesive composition, wherein the ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the acrylic block copolymer (A) is 1.8 or less,
Acrylic block copolymer (A) is an atom having an organic halide or sulfonyl halide compound as an initiator and a metal complex having at least one selected from Fe, Ru, Ni and Cu as a central metal as a catalyst. The above-mentioned pressure-sensitive adhesive composition characterized by being produced by a transfer radical polymerization method,
The above pressure-sensitive adhesive composition, wherein the anti-blocking agent is at least one inorganic substance selected from the group consisting of silica, calcium carbonate, and talc,
The above-mentioned pressure-sensitive adhesive composition, wherein the anti-blocking agent comprises a (meth) acrylic resin and a crosslinked product thereof,
There is.
Moreover, as another embodiment, the adhesive tapes using said adhesive composition,
Re-peelable pressure-sensitive adhesive tapes comprising the above pressure-sensitive adhesive composition,
A surface protective material and a masking material using the above-mentioned pressure-sensitive adhesive composition,
There is.

  The pressure-sensitive adhesive according to the present invention is obtained by externally adding a solid anti-blocking agent to a pellet-shaped or block-shaped pressure-sensitive adhesive composition composed of a pressure-sensitive polymer and a tackifying resin. In the present invention, since the antiblocking agent is compatible with the adhesive polymer, it is possible to form an adhesive layer that is excellent in initial adhesive force and can be easily attached to the adherend surface. Therefore, for example, when a surface protective film having this pressure-sensitive adhesive layer is used, it is possible to prevent dust from adhering to the adherend surface and to prevent the surface from being damaged.

  In the pressure-sensitive adhesive according to the present invention, the stability of the adhesive force with time is enhanced, and the pressure-sensitive adhesive layer is easily peeled off. Furthermore, since adhesive residue and bleed-out of additives hardly occur on the adherend after peeling, contamination of the adherend can be prevented in the case of re-peelable pressure-sensitive adhesive tapes and surface protective films. Furthermore, it is excellent in transparency and light resistance due to the characteristics of acrylic as compared with a pressure-sensitive adhesive mainly composed of a conventional styrene-based or olefin-based block copolymer. Therefore, by using the pressure-sensitive adhesive of the present invention, it is possible to provide pressure-sensitive adhesive tapes excellent in initial pressure-sensitive adhesive force, adhesive strength over time, peeling workability, and coating film contamination prevention properties. Furthermore, since it is excellent in transparency and light resistance, it can be used as a surface protective film in a wide range of fields such as optical use.

  When the anti-blocking agent has compatibility with the hard segment, it is possible to further suppress the adhesive residue on the adherend after peeling and bleeding out of the additive. Furthermore, it is possible to form a pressure-sensitive adhesive layer having excellent initial adhesive strength, temporal stability of adhesive strength, and exfoliation workability. In addition, it can be used for adherends such as polar resins that could not be used with conventional adhesives mainly composed of styrene or olefin block copolymers.

  Details of the present invention will be described below.

  The pressure-sensitive adhesive according to the present invention is adhesive to a pressure-sensitive adhesive composition mainly composed of an acrylic block copolymer (A) comprising a methacrylic polymer block (a) and an acrylic polymer block (b). An anti-blocking agent that is compatible with the polymer at room temperature and is externally added is configured.

<Acrylic block copolymer (A)>
The acrylic block copolymer (A) constituting the pressure-sensitive adhesive composition of the present invention includes a methacrylic polymer block (a) mainly composed of a methacrylic acid ester and an acrylic based material mainly composed of an acrylate ester. It is an acrylic block copolymer (A) comprising a polymer block (b). The structure of the acrylic block copolymer (A) may be either a linear block copolymer, a branched (star) block copolymer, or a mixture thereof. The structure of such a block copolymer is appropriately selected according to the required physical properties of the acrylic block copolymer (A). However, in terms of cost and ease of polymerization, linear block copolymer Coalescence is preferred.

  The linear block copolymer may have any structure. From the viewpoint of the physical properties of the linear block copolymer and the composition, the methacrylic polymer block (a) is a, acrylic. When the polymer block (b) is expressed as b, (ab) n type, b- (ab) n type and (ab) na type (n is an integer of 1 or more, for example, It is preferably made of at least one acrylic block copolymer selected from the group consisting of 1 to 3). Among these, an ab type diblock copolymer, an abb type triblock copolymer, or a mixture thereof is preferable from the viewpoint of easy handling during processing and physical properties of the composition.

  The number average molecular weight (Mn) of the acrylic block copolymer (A) constituting the pressure-sensitive adhesive composition of the present invention is appropriately set according to the properties required for the acrylic block copolymer (A). 30,000 to 300,000 is preferable. If the number average molecular weight is less than 30,000, the cohesive force is inferior and the adhesive properties tend to be reduced. If the number average molecular weight is greater than 300,000, the workability and fluidity tend to be reduced. In addition, the said number average molecular weight shows the value measured by polystyrene conversion by the gel permeation chromatography (GPC) which uses chloroform as a mobile phase and uses a polystyrene gel column.

  The ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the acrylic block copolymer (A) measured by GPC is not particularly limited, but is preferably 1.8 or less. It is more preferably 1.7 or less, further preferably 1.5 or less, and most preferably 1.4 or less. If Mw / Mn exceeds 1.8, the adhesive properties may deteriorate.

  The ratio of the methacrylic polymer block (a) in the acrylic block copolymer (A) is 10 to 50% by weight. When the proportion of the methacrylic polymer block (a) is less than 10% by weight, the cohesive force is poor and the adhesive residue tends to be generated, and the shape is hardly held and the handling property tends to be inferior. When the proportion of the methacrylic polymer block (a) is more than 50% by weight, the viscoelastic properties required for the pressure-sensitive adhesive are inferior, and the adhesive strength tends to decrease.

<Methacrylic polymer block (a)>
The methacrylic polymer block (a) is a block formed by polymerizing a monomer mainly composed of a methacrylic acid ester. Here, the main component means that 50% by weight or more of the monomers constituting the methacrylic polymer block (a) is methacrylic acid and / or methacrylic acid ester.

  Examples of the methacrylate ester include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, isobutyl methacrylate, and n-methacrylate. Pentyl, n-hexyl methacrylate, n-heptyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, nonyl methacrylate, decyl methacrylate, dodecyl methacrylate, stearyl methacrylate, etc. Methacrylic acid aliphatic hydrocarbon (e.g., alkyl having 1 to 18 carbon atoms); methacrylic acid alicyclic hydrocarbon ester such as cyclohexyl methacrylate and isobornyl methacrylate; methacrylic acid such as benzyl methacrylate Aralkyles Methacrylic acid aromatic hydrocarbon ester such as phenyl methacrylate and toluyl methacrylate; functional group having methacrylic acid and etheric oxygen such as 2-methoxyethyl methacrylate and 3-methoxybutyl methacrylate Esters with containing alcohols; trifluoromethyl methacrylate, trifluoromethyl methyl methacrylate, 2-trifluoromethyl ethyl methacrylate, 2-trifluoroethyl methacrylate, 2-perfluoroethyl ethyl methacrylate, 2-perfluoroethyl-2-perfluorobutylethyl methacrylate, 2-perfluoroethyl methacrylate, perfluoromethyl methacrylate, diperfluoromethyl methyl methacrylate, 2-perfluoromethyl methacrylate 2-pa Trifluoroethyl methyl, methacrylic acid 2-perfluorohexylethyl, meta 2- perfluorodecyl acrylate, etc. methacrylic acid fluorinated alkyl esters such as meta 2-perfluoro-hexadecyl acrylate and the like. Among these, methyl methacrylate is preferable. These may be used alone or in combination of two or more.

  The methacrylic polymer block (a) contains a methacrylic acid ester as a main component, but may contain 50 to 0% by weight of a vinyl monomer other than the methacrylic acid ester copolymerizable therewith. . Examples of the copolymerizable vinyl monomer include acrylic acid esters, aromatic alkenyl compounds, vinyl cyanide compounds, conjugated diene compounds, halogen-containing unsaturated compounds, silicon-containing unsaturated compounds, vinyl ester compounds, and maleimides. Compound etc. can be mentioned.

  Examples of the acrylate ester include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-pentyl acrylate, n-hexyl acrylate, Acrylic aliphatic hydrocarbons such as n-heptyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, decyl acrylate, dodecyl acrylate, stearyl acrylate, etc. (eg, alkyl having 1 to 18 carbon atoms) ) Esters; Acrylic alicyclic hydrocarbon esters such as cyclohexyl acrylate and isobornyl acrylate; Aromatic aromatic hydrocarbon esters such as phenyl acrylate and toluyl acrylate; Aralkyl acrylates such as benzyl acrylate; Esters of acrylic acid and functional group-containing alcohol having etheric oxygen such as 2-methoxyethyl acrylate and 3-methoxybutyl acrylate; trifluoromethyl methyl acrylate, 2-trifluoromethyl ethyl acrylate, acrylic acid 2-perfluoroethylethyl, 2-perfluoroethyl-2-perfluorobutylethyl acrylate, 2-perfluoroethyl acrylate, perfluoromethyl acrylate, diperfluoromethyl methyl acrylate, 2-perfluoro acrylate Examples thereof include fluorinated alkyl acrylates such as methyl-2-perfluoroethylmethyl, 2-perfluorohexylethyl acrylate, 2-perfluorodecylethyl acrylate, and 2-perfluorohexadecylethyl acrylate. .

  Examples of the aromatic alkenyl compound include styrene, α-methylstyrene, p-methylstyrene, p-methoxystyrene, and the like.

  Examples of the vinyl cyanide compound include acrylonitrile and methacrylonitrile.

  Examples of the conjugated diene compound include butadiene and isoprene.

  Examples of the halogen-containing unsaturated compound include vinyl chloride, vinylidene chloride, perfluoroethylene, perfluoropropylene, and vinylidene fluoride.

Examples of the vinyl ester compound include vinyl acetate, vinyl propionate, vinyl pivalate, vinyl benzoate, vinyl cinnamate, and the like.
Examples of the maleimide compound include maleimide, methylmaleimide, ethylmaleimide, propylmaleimide, butylmaleimide, hexylmaleimide, octylmaleimide, dodecylmaleimide, stearylmaleimide, phenylmaleimide, cyclohexylmaleimide and the like.

<Acrylic polymer block (b)>
The acrylic polymer block (b) is a block formed by polymerizing a monomer mainly composed of an acrylate ester. The main component means that 50% by weight or more of the monomers constituting the acrylic polymer block (b) is an acrylate ester.

  As the acrylate ester, the same acrylate ester used in the methacrylic polymer block (a) can be used. Among these, butyl acrylate and 2-ethylhexyl acrylate are preferable. These may be used alone or in combination of two or more.

  The acrylic polymer block (b) contains an acrylate ester as a main component, but may contain 50 to 0% by weight of a vinyl monomer other than the acrylate ester copolymerizable therewith. Examples of the different types of copolymerizable vinyl monomers include methacrylic acid esters, aromatic alkenyl compounds, vinyl cyanide compounds, conjugated diene compounds, halogen-containing unsaturated compounds, silicon-containing unsaturated compounds, and vinyl. Examples thereof include ester compounds and maleimide compounds.

  In the present invention, a block composed of 50% by weight of acrylic ester and 50% by weight of methacrylic ester is classified as an acrylic polymer block (b).

<Carboxyl group and / or acid anhydride group>
The acrylic block copolymer (A) constituting the pressure-sensitive adhesive composition of the present invention may contain, as necessary, a carboxyl group and / or an acid anhydride group (hereinafter simply referred to as a functional group) in at least one polymer block. Can be introduced). By introducing a functional group, it is possible to increase the adhesion to the adherend and the adhesion at high temperatures.

  When introducing these functional groups, it is particularly preferred that they are contained in the acrylic polymer block (b). This is because the adhesive force at high temperature can be maintained by increasing the cohesive force of the acrylic polymer block (b).

  Moreover, the adhesive force with respect to a polar base material in the case of using as an adhesive tape can be heightened by raising the polarity of an acrylic polymer block (b). Examples of the polar base material include various metal plates, painted plates, glass plates, polar resin plates such as polyester, polycarbonate, acrylic, nylon, and melamine.

  The content of these functional groups is preferably 0.1 to 30% by weight in the polymer block containing the functional groups. When the content is less than 0.1% by weight, the effect of improving the adhesive strength is poor, and when it is 30% by weight or more, the glass transition temperature (Tg) of the polymer block becomes too high, and the adhesive property tends to be lowered. There is.

  The method for introducing these functional groups into the acrylic block copolymer (A) is not particularly limited, and a method of copolymerizing a monomer having the functional group, and a functional group serving as a precursor of the functional group. For example, there is a method in which the functional group is produced by a known chemical reaction after copolymerization of the monomer having the same.

  Examples of the monomer having a carboxyl group include unsaturated carboxylic acid compounds such as (meth) acrylic acid, unsaturated dicarboxylic acid compounds such as maleic acid and fumaric acid, and monoester compounds thereof. In addition, (meth) acryl shall mean acryl or methacryl.

  Examples of the monomer having a functional group that becomes a precursor of a carboxyl group include t-butyl (meth) acrylate, trimethylsilyl (meth) acrylate, isopropyl (meth) acrylate, and (meth) acrylic acid α. , Α-dimethylbenzyl, α-methylbenzyl (meth) acrylate, and the like. After these monomers are polymerized, a carboxyl group can be generated by hydrolysis, acid decomposition, thermal decomposition or the like.

  Examples of the monomer having an acid anhydride group include maleic anhydride.

  Examples of the monomer having a functional group that serves as a precursor of an acid anhydride group include the monomer having a carboxyl group and the monomer having a functional group that serves as a precursor of a carboxyl group. It is done. After these monomers are polymerized, an acid anhydride group can be generated by a dehydration reaction or a dealcoholization reaction.

<Method for producing acrylic block copolymer (A)>
Although it does not specifically limit as a method to manufacture an acryl-type block copolymer (A), It is preferable to use a control polymerization method. Controlled polymerization methods include living anion polymerization (JP-A-11-335432), polymerization using an organic rare earth transition metal complex as a polymerization initiator (JP-A-6-93060), radical polymerization using a chain transfer agent (special Kaihei 2-45511), a living radical polymerization method and the like.

  Living radical polymerization methods include, for example, a polymerization method using a chain transfer agent such as polysulfide, a polymerization method using a cobalt porphyrin complex, a polymerization method using a nitroxide (WO 2004/014926), and a high-cycle heteroelement compound such as an organic tellurium compound. And the like. (Polymer No. 3839829), Reversible Addition / Desorption Chain Transfer Polymerization (RAFT) (Patent No. 3639859), Atom Transfer Radical Polymerization (ATRP) (Patent No. 3040172), and the like. In the present invention, any of these methods is not particularly limited, but the atom transfer radical polymerization method is preferable from the viewpoint of easy control.

  As a method for producing the acrylic block copolymer (A) using the atom transfer radical polymerization method, for example, the method described in WO2004 / 013192 can be used.

<Adhesive composition>
In the pressure-sensitive adhesive composition of the present invention, various materials such as an anti-aging agent, an ultraviolet absorber, a tackifier, a plasticizer (oil), a tackifier resin, and an adhesion progress preventive agent which are usually used are counter to the object of the present invention. You may use in the range which does not.

  Examples of the anti-adhesion progress agent include fatty acid amides, polyethyleneimine long-chain alkyl grafts, soybean oil-modified alkyd resins (for example, Arakawa Chemical Co., Ltd., trade name “Arachid 251”), tall oil-modified alkyd resins (for example, Arakawa Chemical Co., Ltd., trade name “Arachid 6300”, etc.).

  As described above, the pressure-sensitive adhesive according to the present invention is an anti-blocking agent that is compatible with the pressure-sensitive adhesive composition mainly composed of the acrylic block copolymer (A) and the acrylic block copolymer (A). Is added.

  The compatibility between the adhesive polymer and the antiblocking agent is evaluated by the following method.

  1 part by weight of an antiblocking agent is melt blended with 100 parts by weight of an adhesive polymer to produce a 1 mm thick press sheet. When this press sheet is observed visually and an aggregate of the antiblocking agent is seen, it is assumed that the press sheet is not compatible.

  The anti-blocking agent is not particularly limited as long as it is solid at room temperature, is non-self-adhering, and is compatible with the adhesive polymer. For example, ethylene bis stearamide, Typical examples include amide compounds such as oleic acid amide, stearic acid amide, and ethylene bisoleic acid amide, fatty acid esters such as neopentyl polyol fatty acid ester, and metal soaps such as calcium stearate, aluminum stearate, zinc stearate, and magnesium stearate. Such as low molecular weight compounds, styrenic resins, (meth) acrylic resins, olefinic resins and other polymer material particles having a phase transition temperature (Tg or Tm) higher than room temperature, their cross-linked particles, mica, diatom Soil, white clay, silica (fumed silica, precipitated silica, crystalline silica , Fused silica, porous silica, dolomite, anhydrous silicic acid, hydrous silicic acid, etc., calcium carbonate (heavy calcium carbonate, colloidal calcium carbonate), magnesium carbonate, diatomaceous earth, calcined clay, clay, talc, titanium oxide, bentonite And inorganic compounds such as organic bentonite, ferric oxide, red pepper, fine aluminum powder, flint powder, zinc oxide, activated zinc white, zinc dust, zinc carbonate and shirasu balloon.

  In the case of silica, silica whose surface has been previously hydrophobically treated with an organosilicon compound such as organosilane, organosilazane, or diorganopolysiloxane may be used. Furthermore, calcium carbonate is surface-treated using surface treatment agents such as organic substances such as fatty acids, fatty acid soaps and fatty acid esters, various surfactants, and various coupling agents such as silane coupling agents and titanate coupling agents. You may use what has been given. These may be used independently and 2 or more types may be used together.

  In particular, any anti-blocking agent having compatibility with at least one of the methacrylic polymer block (a) and the acrylic polymer block (b) can be used, but the methacrylic polymer block (a An anti-blocking agent that is compatible with) is preferably used.

  As an antiblocking agent having compatibility with the methacrylic polymer block (a), resins such as (meth) acrylic, polyamide-based, polyester-based, and polyurethane-based resins and cross-linked products thereof, silica, calcium carbonate, talc, etc. The inorganic substance is mentioned.

  Specifically, nylon 6 and nylon 6,6 are pulverized as the polyamide resin, polyethylene terephthalate and polybutylene terephthalate are pulverized as the polyester resin, and polymethyl methacrylate is pulverized as the acrylic resin. And those obtained by micronizing the above particles in a solvent, and cross-linked particles in which a cross-linked structure is introduced in accordance with the micronization.

  Among the antiblocking agents, (meth) acrylic resins and their crosslinked particles, silica, calcium carbonate, and talc are preferably used. Talc is preferred in terms of cost and antiblocking ability, and (meth) acrylic resins and crosslinked particles thereof are preferred from the viewpoints of transparency and adhesive properties of the resulting film. From the viewpoint of compatibility with the acrylic block copolymer (A), (meth) acrylic resins and crosslinked particles thereof are particularly preferable. Specific examples of commercially available (meth) acrylic resins include, but are not limited to, Kane Ace FM40, FM50 (manufactured by Kaneka Corporation), MA1002, MA1006 (manufactured by Nippon Shokubai Co., Ltd.), Sumipex EX-A, LG-A, LG-6A (manufactured by Sumitomo Chemical Co., Ltd.) and the like can be mentioned.

  As the anti-blocking agent, a commercially available powdery product may be used in advance, or a pellet or the like that has been pulverized with a mixer such as a Hensyl mixer may be used.

  The anti-blocking agent is preferably in the form of a powder at normal temperature. Moreover, it is preferable that the average particle diameter of an antiblocking agent is the range of 0.5-50 micrometers. When the average particle size is 0.5 μm or less, the handleability is deteriorated because it is too small, and when it is 50 μm or more, the effect as an antiblocking agent may not be sufficiently exhibited. The average particle diameter is more preferably in the range of 3 to 20 μm.

  A preferable addition amount of the antiblocking agent is in the range of 100 ppm to 20000 ppm with respect to 100 parts by weight of the total pressure-sensitive adhesive composition. If the amount added is less than 100 ppm, sufficient anti-blocking performance may not be exhibited. If the amount added exceeds 20000 ppm, the adhesive properties may be adversely affected.

  Examples of a method for externally adding an antiblocking agent to the pressure-sensitive adhesive composition include a dry blending method using a turbula shaker mixer, a Henschel mixer, a ribbon blender, a spar mixer, a V blender, or the like. Moreover, the method of blending in air currents, such as air transfer and a fluid dryer, is also mentioned.

  The pressure-sensitive adhesive configured as described above may be either granular or massive at room temperature. Specifically, granular indicates a pellet state, and includes ordinary cylindrical and circular pellets. The lump indicates a block lump.

The shear storage modulus at a frequency of 10 Hz of the pressure-sensitive adhesive is preferably in the range of 5 × 10 ^{4 to} 5 × 10 ⁶ Pa at 23 ° C. When the shear storage elastic modulus is outside this range, the surface protective film may be peeled off from the adherend due to insufficient adhesive force, or workability in the peeling step may be deteriorated.

The pressure-sensitive adhesive tapes (tape, sheet, film) using the pressure-sensitive adhesive composition of the present invention may be those in which a pressure-sensitive adhesive layer is formed on one side of the base material, and the base material is conventionally known, for example, Polypropylene resin, polyethylene resin or polyolefin resin obtained by blending them, polyvinyl chloride resin, polyester resin, paper, cloth and the like. The olefin-based substrate is not particularly limited, and polyolefins such as polypropylene and polyethylene, polyolefins mixed with olefin-based elastomers, and the like can be used.

  In addition, the said base material may give a corona treatment and a primer treatment as needed, and may give a back surface process etc. In addition, a slip agent, an antistatic agent, and an antioxidant can be added to the substrate as necessary.

  Although the thickness of a base material is not specifically limited, The range of 10-200 micrometers is desirable. When the thickness is less than 10 μm, the tensile properties are inferior. For example, when it is used as a protective film, a sufficient protective function may not be exhibited. When the thickness exceeds 200 μm, followability to a non-smooth portion such as a curved surface portion of an adherend is obtained. May be inferior.

  Although the thickness of the adhesive layer laminated | stacked on a base material is not specifically limited, The range of 3-50 micrometers is desirable. If the thickness is less than 3 μm, the adhesive strength may be insufficient, and if it exceeds 50 μm, the cost may increase.

  Since the pressure-sensitive adhesive composition of the present invention usually melts easily and exhibits fluidity, the above-mentioned pressure-sensitive adhesive layer can be formed on a substrate by a hot melt method. Examples of the method for producing the pressure-sensitive adhesive layer include a method in which a pressure-sensitive adhesive composition and a base material are subjected to melt multilayer extrusion, a method in which the pressure-sensitive adhesive composition is laminated on a base material, and the like. For melt multilayer extrusion, for example, a T-die molding method, air-cooled inflation, or water-cooled inflation is employed. Moreover, for example, a calendar method is employed as a method of laminating the pressure-sensitive adhesive composition.

  The pressure-sensitive adhesive tape, sheet, and film can be prepared by a solution method, and the pressure-sensitive adhesive composition of the present invention is dissolved in toluene or other solvent to form a solution, which is applied to a substrate to form a pressure-sensitive adhesive layer. You can also.

<Use of pressure-sensitive adhesive composition>
The pressure-sensitive adhesive composition according to the present invention can be suitably used as pressure-sensitive adhesive tapes (tapes, sheets, films). Adhesive tapes include surface protection, masking, packaging, office, household, label, bonding, sealing, anticorrosion / waterproof, electrical insulation, electronic device holding and fixing, semiconductor manufacturing, It can be used as an adhesive material used for tapes and films for electronic device masking, optical display films, electromagnetic shielding, medical / hygiene, decoration / display, and glass scattering prevention tapes and films.

  Examples of the surface protection include metal, paint surface protection, metal plastic working, and metal deep drawing.

  Specific examples of masking include painting of vehicles and buildings, textile printing, automobiles, civil engineering / construction, and parting.

  Examples of packaging include heavy goods packaging, export packaging, cardboard box sealing, can seals, pipe / steel bundling, ducts, food plastic bag bundling, vegetables and flower bundling.

  Examples of office use include general office use, home use, sealing, book repair, drafting, and memo.

  Examples of labels include price, product display, tag, POP, sticker, stripe, name plate, decoration, and advertisement.

  Examples of bonding include various bonding fields, automobiles, trains, electrical equipment, printing plate fixing, construction, nameplate fixing, general household use, rough surfaces, uneven surfaces, and bonding to curved surfaces.

  Examples of the sealing include heat insulation, vibration proof, water proof, moisture proof, soundproof, and dust proof.

  Examples of anticorrosion / waterproofing include gas, water pipe corrosion prevention, large-diameter pipe corrosion prevention, anti-corrosion prevention, and civil engineering / building corrosion prevention.

  Examples of the electrical insulation include coil protection coating, motor / transformer interlayer insulation, coil insulation, bundling and the like.

  Examples of the electronic device holding and fixing include carrier tape, packaging, CRT fixing, splicing, FD, and rib reinforcement.

  Examples of semiconductor manufacturing include protection of silicone wafers.

  Examples of electronic device masking include plating masking and solder masking.

  Examples of medical and hygiene include adhesive bandages, emergency bandages, surgical dressings, surgical suture tapes, salicylic acid bandages, poultices, anti-inflammatory analgesic plasters, percutaneous absorption drugs, fixed taping, hair removal, dust prevention, and insect trapping.

  Examples of decoration and display include danger label seals, line tapes, wiring markings, phosphorescent tapes, and reflective sheets.

  EXAMPLES Although this invention is demonstrated further in detail based on an Example, this invention is not limited only to these Examples. In the examples, BA, MMA, and TBA represent acrylate-n-butyl, methyl methacrylate, and t-butyl acrylate, respectively.

<Molecular weight measurement method>
The molecular weight shown in this example was measured by the GPC analyzer shown below, and the molecular weight in terms of polystyrene was determined using chloroform as the mobile phase. As a system, a GPC system manufactured by Waters was used, and Shodex K-804 (polystyrene gel) manufactured by Showa Denko Co., Ltd. was used for the column.

<Method for measuring conversion rate of polymerization reaction>
The conversion rate of the polymerization reaction shown in this example was measured using the following analyzer and conditions.
Equipment used: Gas chromatography GC-14B manufactured by Shimadzu Corporation
Separation column: J & W SCIENTIFIC INC, capillary column DB-17, 0.35 mmφ × 30 m
Separation conditions: Initial temperature 50 ° C., hold for 3.5 minutes
Temperature increase rate 40 ° C / min
Final temperature 140 ° C, hold for 1.5 minutes
Injection temperature 250 ° C
Detector temperature 250 ° C
Sample preparation: The sample was diluted about 10 times with ethyl acetate, and acetonitrile was used as an internal standard substance.

<Compatibility evaluation>
The compatibility of the antiblocking agents shown in the examples and comparative examples with the acrylic block copolymer was evaluated by the following method.

  According to the examples and comparative examples, a 1 mm thick sheet was prepared and then visually observed. When an aggregate of the antiblocking agent was seen, the sheet was not compatible.

Evaluation index:
Those where the anti-blocking agent aggregates are not visible: ○
What can see the aggregate of an antiblocking agent: ×

Production Example 1 Production of Carboxyl Group-Containing Acrylic Block Copolymer 1 As a monomer constituting the acrylic polymer block, 80.9 kg of BA and 2.1 kg of TBA were charged into a nitrogen-substituted 500 L reactor, 580 g of cuprous bromide was charged and stirring was started. Thereafter, a solution prepared by dissolving 583 g of diethyl 2,5-dibromoadipate in 7.3 kg of acetonitrile was charged, and the jacket was heated and held at an internal temperature of 75 ° C. for 30 minutes. Thereafter, 70 g of pentamethyldiethylenetriamine was added to initiate polymerization of the acrylic polymer block. About 100 g of the polymerization solution was sampled for sampling from the polymerization solution at regular intervals from the start of polymerization, and the conversion rate of BA was determined by gas chromatogram analysis of the sampling solution. The polymerization rate was controlled by adding pentamethyldiethylenetriamine as needed.

  When the conversion rate of BA reached 97%, 82.5 kg of toluene, 400 g of cuprous chloride, 70 g of pentamethyldiethylenetriamine, and 35.6 kg of MMA were added as monomers constituting the methacrylic polymer block, Polymerization of the methacrylic polymer block was started. When the MMA conversion rate reached 90%, 120 kg of toluene was added to dilute the reaction solution, and the reactor was cooled to terminate the polymerization.

  Toluene was added to the resulting acrylic block copolymer solution to make the polymer concentration 25% by weight. 1.6 kg of p-toluenesulfonic acid monohydrate was added to this solution, the inside of the reactor was purged with nitrogen, and the mixture was stirred at 150 ° C. for 4 hours to convert the t-butyl group of TBA into a carboxyl group. Thereafter, 2.3 kg of Radiolite # 3000 manufactured by Showa Chemical Industry was added as a filter aid, and pressure filtered at 0.1 to 0.4 MPaG using a pressure filter equipped with a polyester felt as a filter medium. Separated the minutes.

  The obtained acidic solution was again put into a 500 L reactor, 3.4 kg of Kyowa Chemical Kyodo 500SH was added as a solid base, and the mixture was stirred at 30 ° C. for 1 hour. Thereafter, using a pressure filter equipped with polyester felt as a filter medium, the solid content is separated by pressure filtration at 0.1 to 0.4 MPaG, and the target carboxyl group-containing acrylic block copolymer 1 is obtained. A solution was obtained. After adding 0.6 parts by weight of Irganox 1010 (manufactured by Ciba Specialty Chemicals) to the obtained polymer solution with respect to the weight of the polymer, SCP100 (manufactured by Kurimoto Steel Works, The solvent component was evaporated using a heat transfer area of 1 m2). The polymer was made into a strand through a φ4 mm die, cooled in a water bath, and polymer pellets were obtained by a pelletizer.

  When the GPC analysis of the obtained carboxyl group-containing acrylic block copolymer 1 was conducted, the number average molecular weight (Mn) was 109,000 and the molecular weight distribution (Mw / Mn) was 1.34.

(Production Example 2) Production of acrylic block copolymer 2 83.0 kg of BA is used as a monomer constituting the acrylic polymer block, and MMA 35.6 kg is used as a monomer constituting the methacrylic polymer block. Polymerization was carried out in the same manner as in Production Example 1 except that was used.

  Toluene was added to the resulting acrylic block copolymer solution to make the polymer concentration 25% by weight. 1.6 kg of p-toluenesulfonic acid monohydrate was added to this solution, the inside of the reactor was purged with nitrogen, and the mixture was stirred at 30 ° C. for 3 hours. The reaction solution was sampled to confirm that the solution was colorless and transparent, and 2.3 kg of Radiolite # 3000 manufactured by Showa Chemical Industry was added. Thereafter, pressure filtration was performed at 0.1 to 0.4 MPaG using a pressure filter equipped with polyester felt as a filter medium to separate a solid content.

  This polymer solution was dried by the same operation as in Production Example 1 to obtain the desired acrylic block copolymer 2 pellets. When the GPC analysis of the obtained acrylic block copolymer 2 was conducted, the number average molecular weight (Mn) was 109,000 and the molecular weight distribution (Mw / Mn) was 1.31.

Example 1
200 parts by weight of MA1002 (manufactured by Nippon Shokubai Co., Ltd.), which is a crosslinked particle of (meth) acrylic resin, with respect to 100 parts by weight (45 g) of polymer 1 obtained in Production Example 1, Using a Laboplast mill 50C150 (blade shape: roller type R60, Toyo Seiki Seisakusho, Ltd.) set to ° C., the mixture was melt-kneaded at 100 rpm for 10 minutes to obtain a lump sample. Furthermore, the obtained sample was subjected to hot press molding (compression molding machine NSF-50, manufactured by Kamito Metal Industry Co., Ltd.) for 3 minutes at a set temperature of 200 ° C. using a 1 mm metal spacer, and evaluation was performed with a thickness of 1 mm. A molded body of was obtained. The compatibility of these molded products was evaluated. The results are shown in Table 1.

(Example 2)
Evaluation was performed in the same manner as in Example 1 except that the type of the anti-blocking agent was changed to TALC-LMR (Fuji Talc Kogyo Co., Ltd.), which is talc powder. The results are shown in Table 1.

(Example 3)
Evaluation was performed in the same manner as in Example 1 except that the type of the acrylic block copolymer was changed to the polymer 2 obtained in Production Example 2. The results are shown in Table 1.

Example 4
Evaluation was performed in the same manner as in Example 1 except that the type of the acrylic block copolymer and the type of the antiblocking agent were changed. The results are shown in Table 1.

(Comparative Example 1)
Evaluation was performed in the same manner as in Example 1 except that the type of the antiblocking agent was changed to Mipperon XM220 (manufactured by Mitsui Chemicals, Inc.), which is an ultrahigh molecular weight polyethylene powder. The results are shown in Table 1.

(Comparative Example 2)
Evaluation was performed in the same manner as in Example 1 except that the type of the acrylic block copolymer and the type of the antiblocking agent were changed. The results are shown in Table 1.

(Example 5)
Using a three-layer film manufacturing apparatus (Toyo Seiki Seisakusho Co., Ltd.) having a screw diameter of 20 mm and L / D = 20, a multilayer film was formed at a screw rotation speed of 20 rpm. In this three-layer film manufacturing apparatus, three extrusion groups are connected to a flat die by a feed block. F227D (Prime Polymer Co., Ltd.) (outermost layer and intermediate layer) which is polypropylene as a base resin from two of the three units, TALC-LMR (manufactured by Fuji Talc Industrial Co., Ltd.) as an antiblocking agent from one A dry blend of 2 parts by weight of 100 parts by weight of acrylic block copolymer pellets was extruded as an adhesive layer (the other outermost layer) to form a multilayer. The set temperature of the extruder, feed block, and die was all set to 180 ° C. The die lip clearance was set to 300 μm, and the film winding speed was adjusted to obtain a multilayer film having a thickness of about 50 μm. The obtained multilayer sheet was transparent and no aggregates of the antiblocking agent were visually observed. Moreover, when the layer which consists of an acrylic block copolymer of the obtained sheet | seat was used as the adhesion layer and it affixed on the display of a mobile telephone, it stuck well. Further, when it was peeled off again from the mobile phone, it could be easily peeled off without leaving a sticking mark on the display.

表１の実施例１〜４および比較例１〜２からわかるように、アクリル系ブロック共重合体と相溶性を有するブロッキング防止剤を用いた場合は、ブロッキング防止剤の凝集物が生じないことがわかる。また実施例５に示したように、アクリル系ブロック共重合体と相溶性を有するブロッキング防止剤を用いて、基材樹脂と多層成形して得られた粘着フィルムは、透明かつブロッキング防止剤の凝集物が見られなかった。また、粘着特性に優れることから、保護フィルム等として好適に用いることができる。

As can be seen from Examples 1 to 4 and Comparative Examples 1 and 2 in Table 1, when an anti-blocking agent having compatibility with the acrylic block copolymer is used, an aggregate of the anti-blocking agent may not occur. Recognize. In addition, as shown in Example 5, the adhesive film obtained by multilayer molding with the base resin using the antiblocking agent having compatibility with the acrylic block copolymer is transparent and aggregated of the antiblocking agent. I couldn't see anything. Moreover, since it is excellent in an adhesive characteristic, it can be used suitably as a protective film etc.

Claims (11)

  An anti-blocking agent that is solid at room temperature is added to a pressure-sensitive adhesive composition comprising an acrylic block copolymer (A) composed of a methacrylic polymer block (a) and an acrylic polymer block (b) as a main component. The pressure-sensitive adhesive composition is characterized in that the anti-blocking agent is compatible with the pressure-sensitive adhesive polymer.   The acrylic block copolymer (A) comprises a methacrylic polymer block (a) and an acrylic polymer block (b), and at least one polymer block has a carboxyl group and / or an acid anhydride group. The pressure-sensitive adhesive composition according to claim 1, which is an acrylic block copolymer (A).   The pressure-sensitive adhesive according to any one of claims 1 to 2, wherein the acrylic block copolymer (A) has a carboxyl group and / or an acid anhydride group in the acrylic polymer block (b). Composition.   The pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein the proportion of the methacrylic polymer block (a) in the acrylic block copolymer (A) is 10 to 50% by weight. object.   The pressure-sensitive adhesive composition according to any one of claims 1 to 4, wherein the acrylic block copolymer (A) is a diblock copolymer, a triblock copolymer, or a mixture thereof.   The pressure-sensitive adhesive composition according to any one of claims 1 to 5, wherein the acrylic block copolymer (A) has a number average molecular weight (Mn) of 30,000 to 300,000.   The ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the acrylic block copolymer (A) is 1.8 or less. 2. The pressure-sensitive adhesive composition according to 1.   Acrylic block copolymer (A) is an atom having an organic halide or sulfonyl halide compound as an initiator and a metal complex having at least one selected from Fe, Ru, Ni and Cu as a central metal as a catalyst. The pressure-sensitive adhesive composition according to any one of claims 1 to 7, wherein the pressure-sensitive adhesive composition is produced by a transfer radical polymerization method.   A pressure-sensitive adhesive tape comprising the pressure-sensitive adhesive composition according to claim 1.   Re-peelable pressure-sensitive adhesive tapes using the pressure-sensitive adhesive composition according to claim 1. A surface protective material and a masking material comprising the pressure-sensitive adhesive composition according to claim 1.