JPWO2007029783A1 - Acrylic adhesive composition and adhesive product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive composition and a pressure-sensitive adhesive product having excellent weather resistance, heat resistance and water resistance. SOLUTION: At least one polymer block (A) comprising 23 to 98% by mass of a methacrylic acid alkyl ester unit such as methyl methacrylate and an acryl such as octyl acrylate having an alkyl group with 6 to 18 carbon atoms. 77-2% by mass of at least one polymer block (B) comprising an acid alkyl ester unit, a weight average molecular weight of 5,000-1,000,000, and a molecular weight distribution of 1.0-1 A pressure-sensitive adhesive composition comprising an acrylic block copolymer of 0.5, a tackifier resin having a solubility parameter value of 8 to 11, and a pressure-sensitive adhesive product having a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition.

Description

  The present invention relates to a pressure-sensitive adhesive composition containing a specific (meth) acrylic block copolymer and excellent in weather resistance, heat resistance, and water resistance.

  Acrylic adhesives are widely used in adhesive tapes, adhesive sheets, and the like because they have superior weather resistance and heat resistance compared to rubber adhesives. The acrylic copolymer used as the base polymer of the acrylic pressure-sensitive adhesive is usually a random copolymer produced by a radical polymerization method, and has a molecular weight distribution [weight average molecular weight (Mw) / number average molecular weight (Mn)]. Is generally as wide as about 2.0 to 5.0. For this reason, low molecular weight components are mixed, and the pressure-sensitive adhesive containing the acrylic copolymer has a problem that the cohesive force under high temperature conditions is insufficient or adhesive residue on the adherend due to cohesive failure occurs. It was. To solve these problems, there is a method to increase the degree of polymerization of the polymer as a means to improve the cohesive force under high temperature conditions. However, industrialization is limited to increasing the degree of polymerization due to limitations of polymerization technology and coating technology. There is no solution to the problem. As another means for improving the cohesive force, there is a method of crosslinking the polymer. However, when a random copolymer produced by a conventional radical polymerization method is used, the crosslinking site cannot be controlled, and the cohesive force can be controlled. Even if improved, there was a problem that the adhesive strength decreased.

  On the other hand, attempts have been made to use an acrylic block copolymer that can be synthesized by a living polymerization method as a base polymer. For example, there are the following reports.

  In Patent Document 1, an iniferter heavy using an iniferter such as xylylene-bis (N, N-diethyldithiocarbamate) or xylylene-bis (N-carbazolyldithiocarbamate). By synthesizing a block copolymer having a polymer block composed of an alkyl methacrylate and a polymer block composed of an alkyl acrylate, the block copolymer can be used as a base polymer for an adhesive. Proposed.

  In Patent Document 2 and Patent Document 3, a polymer block mainly composed of alkyl methacrylate and having a glass transition temperature of + 110 ° C. or higher and a syndiotacticity of 70% or higher, mainly alkyl acrylate and A block copolymer made of an alkyl methacrylate and / or a polymer block having a glass transition temperature of + 30 ° C. or lower has been proposed as a base polymer for pressure-sensitive adhesives.

  In Patent Document 4, a polymer synthesized by an anionic polymerization method is subjected to a transesterification reaction in the presence of an acid to synthesize an acrylic block copolymer, and a pressure-sensitive adhesive composition comprising the block copolymer and a tackifier resin Things have been proposed.

Japanese Patent Laid-Open No. 2-103277 Japanese Patent Laid-Open No. 11-302617 Japanese Patent Laid-Open No. 11-323072 US Pat. No. 6,734,256

  When an acrylic block copolymer is used as a base polymer, the polymer block having a high glass transition temperature becomes a physical cross-linking point by utilizing the formation of a phase separation structure of polymer blocks having different glass transition temperatures. Expresses cohesion. However, the pressure-sensitive adhesives contained in these acrylic block polymers have melting points at high temperatures, and a sufficient cohesive force is not obtained.

  Therefore, an object of the present invention is to provide a pressure-sensitive adhesive composition and a pressure-sensitive adhesive product having excellent weather resistance and heat resistance.

  The present inventors have intensively studied in order to solve the above problems. As a result, it was found that by using a specific acrylic block copolymer, an adhesive composition and an adhesive product excellent in weather resistance and heat resistance can be provided, and the present invention has been completed.

That is, the present invention
At least one polymer block (A) comprising 23 to 98% by mass of a methacrylic acid alkyl ester unit and at least one polymer block comprising an acrylic acid alkyl ester unit having 6 to 18 carbon atoms in the alkyl group ( B) 100 parts by mass of an acrylic block copolymer having 77 to 2% by mass, a weight average molecular weight of 5,000 to 1,000,000, and a molecular weight distribution of 1.0 to 1.5; And 1 to 400 parts by mass of a tackifier resin having a solubility parameter value of 8.0 to 11.0;
Is a pressure-sensitive adhesive composition containing

  Moreover, this invention is an adhesive product which has the adhesion layer which consists of said adhesive composition.

  The pressure-sensitive adhesive composition of the present invention contains a specific acrylic block copolymer and a specific tackifying resin, and has excellent weather resistance, heat resistance, water resistance, and transparency. Furthermore, the pressure-sensitive adhesive composition of the present invention can use a tackifying resin that has conventionally been restricted in use due to different compatibility, depending on the purpose of use such as the type of adherend and required transparency. Many types of tackifying resins can be selected. INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a pressure-sensitive adhesive and a pressure-sensitive adhesive product that can have excellent pressure-sensitive adhesive performance over a long period of time even under an environment exposed to ultraviolet rays or under a use environment condition of high temperature and high humidity.

  The present invention is described in detail below. In this specification, methacryl and acryl may be collectively referred to as “(meth) acryl”. In the present invention, the “pressure-sensitive adhesive” means “pressure-sensitive adhesive”.

The acrylic block copolymer used in the present invention is at least one polymer block (A) composed of methacrylic acid alkyl ester units and at least composed of acrylic acid alkyl ester units having 6 to 18 carbon atoms in the alkyl group. And one polymer block (B). In the acrylic block copolymer, when the polymer block (A) composed of methacrylic acid alkyl ester units is “A”; and the polymer block (B) composed of acrylic acid alkyl ester units is “B”; formula;
(AB) _n
(AB) _n- A
B- (AB) _n
(N is an integer of 1 to 10).

  Examples of the methacrylic acid alkyl ester that is a constituent unit of the polymer block (A) in the above general formula include, for example, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, methacrylic acid. Isobutyl acid, s-butyl methacrylate, t-butyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, lauryl methacrylate, tridecyl methacrylate, stearyl methacrylate, methacryl Examples include methacrylic acid alkyl esters such as isobornyl acid, benzyl methacrylate, and phenyl methacrylate. Among these, when selected from methyl methacrylate and isobornyl methacrylate, the glass transition temperature of the polymer block (A) is increased, and when a pressure-sensitive adhesive composition is obtained, it is preferable in that a high cohesive force is exhibited at a high temperature. Furthermore, in the case of methyl methacrylate, the phase separation between the polymer block (A) and the polymer block (B) becomes clear. preferable. These may be used alone or in combination of two or more.

  Examples of the acrylic acid alkyl ester having an alkyl group having 6 to 18 carbon atoms, which is a structural unit of the polymer block (B) in the general formula, include n-hexyl acrylate, cyclohexyl acrylate, 2-acrylic acid 2- Examples include ethylhexyl, n-octyl acrylate, lauryl acrylate, tridecyl acrylate, stearyl acrylate, and the like. Among them, when selected from 2-ethylhexyl acrylate, n-octyl acrylate, and tridecyl acrylate, the glass transition temperature of the polymer block (B) is low, and a high adhesive strength is obtained when a pressure-sensitive adhesive composition is obtained. Is preferable. Furthermore, in the case of 2-ethylhexyl acrylate, the phase separation between the polymer block A and the polymer block (B) becomes clearer, which is more preferable in terms of expressing high cohesive force. These may be used alone or in combination of two or more. These may be used alone or in combination of two or more. Among these, when selected from 2-ethylhexyl acrylate and n-octyl acrylate, the polymer block (B) has a glass transition temperature of −50 ° C. or lower, and adhesive properties at low temperatures (10 ° C. to −40 ° C.) (tack) In view of excellent adhesive strength and the like. Further, even when peeling at a high speed (for example, 1 m / min to 100 m / min), a slip stick phenomenon (a phenomenon in which peeling occurs suddenly or stops while keeping a certain distance during peeling, also called a zipping phenomenon). This is preferable in that it causes less troubles such as device troubles due to fluctuations in peeling stress, adhesive residue on the adherend, etc.) and exhibits stable adhesive force under a wide range of peeling speed conditions.

  As the block copolymer represented by the above general formula, for example, polymethyl methacrylate-b-polyacrylic acid n-hexyl, polymethyl methacrylate-b-polyacrylic acid 2-ethylhexyl, polymethyl methacrylate- b-polylauryl acrylate, polymethyl methacrylate-b-polyethyl 2-ethylhexyl acrylate-b-polymethyl methacrylate, 2-ethylhexyl polyacrylate-b-polymethyl methacrylate-b-polyethyl acrylate 2-ethylhexyl Etc.

  If the polymer block (A) and the polymer block (B) represented by the above general formula have a small ratio (20% by mass or less in the polymer block) that does not impair the effects of the present invention, other The monomer unit may be included. Examples of monomer units that may be included include methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, and (meth) acrylic. (Meth) acrylic acid ester having a functional group such as 2-aminoethyl acid, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate; (meth) acrylic acid, crotonic acid, maleic acid, maleic anhydride, Vinyl monomers having a carboxyl group such as fumaric acid and (meth) acrylamide; aromatic vinyl monomers such as styrene, α-methylstyrene and p-methylstyrene; conjugated diene monomers such as butadiene and isoprene; ethylene, Olefin monomers such as propylene; ε-caprolactone And lactone monomers such as valerolactone.

  The production method of the block copolymer used in the present invention is not particularly limited as long as a polymer satisfying the conditions of the present invention relating to the chemical structure is obtained, and a method according to a known method may be adopted. it can. In general, as a method of obtaining a block copolymer having a narrow molecular weight distribution, a method of living polymerizing a monomer as a constituent unit is used. Such living polymerization techniques include, for example, a method of polymerizing using an organic rare earth metal complex as a polymerization initiator, and an organic alkali metal compound as a polymerization initiator in the presence of a mineral salt such as an alkali metal or alkaline earth metal salt. And an anionic polymerization in the presence of an organic aluminum compound using an organic alkali metal compound as a polymerization initiator, an atom transfer radical polymerization (ATRP) method, and the like.

  Among the above production methods, when an anionic polymerization method is used in the presence of an organoaluminum compound, a polymer having a narrower molecular weight distribution can be produced, the residual monomer is less, and the molecular structure of the methacrylate polymer block is high. It becomes syndiotactic and has the effect of increasing the cohesive strength at high temperatures when used as an adhesive composition. In addition, because living polymerization is possible under relatively mild temperature conditions, it is possible to reduce the environmental burden (mainly the electric power applied to the refrigerator for controlling the polymerization temperature) for industrial production. There is. From the above points, the block copolymer used in the present invention is preferably produced by an anionic polymerization method in the presence of an organoaluminum compound.

  Furthermore, as a method for producing the block copolymer used in the present invention, a method of directly polymerizing monomers that are constituent units of the block copolymer is preferable. After polymerizing alkyl (meth) acrylate having an alkyl group capable of transesterification after polymerization reaction such as t-butyl (meth) acrylate, ester with any alcohol in the presence of acid such as p-toluenesulfonic acid Although it can also synthesize | combine by an exchange reaction, a carboxylic acid group produces | generates in a polymer by the hydrolysis reaction which occurs as a side reaction of a transesterification reaction, and water resistance may fall.

Examples of the anionic polymerization method in the presence of the above organoaluminum compound include an organolithium compound and the following general formula:
AlR ¹ R ² R ³
Wherein R ¹ , R ² and R ³ are each independently an alkyl group which may have a substituent, a cycloalkyl group which may have a substituent, or an aryl which may have a substituent. A group, an aralkyl group which may have a substituent, an alkoxyl group which may have a substituent, an aryloxy group which may have a substituent or an N, N-disubstituted amino group, or R ¹ represents any of the groups described above, and R ² and R ³ together represent an aryleneoxy group which may have a substituent.)
In the presence of an organoaluminum compound represented by the formula, an ether such as dimethyl ether, dimethoxyethane, diethoxyethane, or 12-crown-4; if necessary, triethylamine, N, N, N ′, N '-Tetramethylethylenediamine, N, N, N', N '', N ''-pentamethyldiethylenetriamine, 1,1,4,7,10,10-hexamethyltriethylenetetramine, pyridine, 2,2'- A method of polymerizing a (meth) acrylic acid ester by further using a nitrogen-containing compound such as dipyridyl can be employed.

  Examples of the organic lithium compound include methyl lithium, ethyl lithium, n-propyl lithium, isopropyl lithium, n-butyl lithium, sec-butyl lithium, isobutyl lithium, tert-butyl lithium, n-pentyl lithium, and n-hexyl lithium. Alkyllithium and alkyldilithium such as tetramethylenedilithium, pentamethylenedilithium and hexamethylenedilithium; aryllithium and aryldilithium such as phenyllithium, m-tolyllithium, p-tolyllithium, xylyllithium and lithium naphthalene Lithium; benzyl lithium, diphenylmethyl lithium, trityl lithium, 1,1-diphenyl-3-methylpentyl lithium, α-methylstyryl lithium, diisopropenyl Aralkyllithium and aralkyldilithium such as dilithium produced by the reaction of benzene and butyllithium; lithium amides such as lithium dimethylamide, lithium diethylamide and lithium diisopropylamide; methoxylithium, ethoxylithium, n-propoxylithium, isopropoxylithium, n -Butoxylithium, sec-butoxylithium, tert-butoxylithium, pentyloxylithium, hexyloxylithium, heptyloxylithium, octyloxylithium, phenoxylithium, 4-methylphenoxylithium, benzyloxylithium, 4-methylbenzyloxylithium, etc. Lithium alkoxide. These may be used alone or in combination of two or more.

  Examples of the organoaluminum compound represented by the above general formula include trimethylaluminum, triethylaluminum, tri-n-butylaluminum, tris-butylaluminum, tri-t-butylaluminum, triisobutylaluminum, and tri-n-hexylaluminum. , Tri-n-octylaluminum, tri2-ethylhexylaluminum, trialkylaluminum such as triphenylaluminum, dimethyl (2,6-di-tert-butyl-4-methylphenoxy) aluminum, dimethyl (2,6-di-tert -Butylphenoxy) aluminum, diethyl (2,6-di-tert-butyl-4-methylphenoxy) aluminum, diethyl (2,6-di-tert-butylphenoxy) aluminum, diisobuty (2,6-di-tert-butyl-4-methylphenoxy) aluminum, diisobutyl (2,6-di-tert-butylphenoxy) aluminum, di-n-octyl (2,6-di-tert-butyl-4 -Methylphenoxy) aluminum, dialkylphenoxyaluminum such as di-n-octyl (2,6-di-tert-butylphenoxy) aluminum, methylbis (2,6-di-tert-butyl-4-methylphenoxy) aluminum, methylbis (2,6-di-tert-butylphenoxy) aluminum, ethyl [2,2′-methylenebis (4-methyl-6-tert-butylphenoxy)] aluminum, ethylbis (2,6-di-tert-butyl-4) -Methylphenoxy) aluminum, ethylbis (2,6-di) tert-butylphenoxy) aluminum, ethyl [2,2′-methylenebis (4-methyl-6-tert-butylphenoxy)] aluminum, isobutylbis (2,6-di-tert-butyl-4-methylphenoxy) aluminum, Isobutylbis (2,6-di-tert-butylphenoxy) aluminum, isobutyl [2,2′-methylenebis (4-methyl-6-tert-butylphenoxy)] aluminum, n-octylbis (2,6-di-tert) -Butyl-4-methylphenoxy) aluminum, n-octylbis (2,6-di-tert-butylphenoxy) aluminum, n-octyl [2,2'-methylenebis (4-methyl-6-tert-butylphenoxy)] Alkyl diphenoxy aluminum such as aluminum , Methoxybis (2,6-di-tert-butyl-4-methylphenoxy) aluminum, methoxybis (2,6-di-tert-butylphenoxy) aluminum, methoxy [2,2′-methylenebis (4-methyl-6) -Tert-butylphenoxy)] aluminum, ethoxybis (2,6-di-tert-butyl-4-methylphenoxy) aluminum, ethoxybis (2,6-di-tert-butylphenoxy) aluminum, ethoxy [2,2'- Methylenebis (4-methyl-6-tert-butylphenoxy)] aluminum, isopropoxybis (2,6-di-tert-butyl-4-methylphenoxy) aluminum, isopropoxybis (2,6-di-tert-butyl) Phenoxy) aluminum, isopropoxy [ , 2′-methylenebis (4-methyl-6-tert-butylphenoxy)] aluminum, tert-butoxybis (2,6-di-tert-butyl-4-methylphenoxy) aluminum, tert-butoxybis (2,6-di) -Tert-butylphenoxy) aluminum, tert-butoxy [2,2'-methylenebis (4-methyl-6-tert-butylphenoxy)] aluminum and other alkoxydiphenoxyaluminum, tris (2,6-di-tert-butyl) Examples include triphenoxyaluminum such as -4-methylphenoxy) aluminum and tris (2,6-diphenylphenoxy) aluminum. Among these organoaluminum compounds, isobutylbis (2,6-di-tert-butyl-4-methylphenoxy) aluminum, isobutylbis (2,6-di-tert-butylphenoxy) aluminum, isobutyl [2,2 ′ -Methylenebis (4-methyl-6-tert-butylphenoxy)] aluminum and the like are easy to handle, and the polymerization of the acrylate can proceed without deactivation under relatively mild temperature conditions. Particularly preferred. These may be used alone or in combination of two or more.

  The overall weight average molecular weight (Mw) of the acrylic block copolymer used in the present invention is 5,000 to 1,000,000. In the production of the pressure-sensitive adhesive composition, it is preferably 10,000 to 500,000, more preferably 10,000 to 100,000, from the viewpoint of easy mixing with the tackifier resin.

  The ratio (Mw / Mn) of the overall weight average molecular weight (Mw) and number average molecular weight (Mn) of the acrylic block copolymer used in the present invention is 1.0 to 1.5. When the pressure-sensitive adhesive composition is used, it is preferably from 1.0 to 1.4, more preferably from 1.0 to 1.3, from the viewpoint of high cohesion at high temperatures.

  The mass ratio of all the polymer blocks (A) and all the polymer blocks (B) in the acrylic block copolymer used in the present invention has excellent adhesiveness when used as an adhesive composition. The polymer block (A) is 23 to 98% by mass and the polymer block (B) 77 because the block copolymer and the pressure-sensitive adhesive using the block copolymer can be supplied in a form that is easy to handle. It is preferable that it is -2 mass%, and it is more preferable that they are a polymer block (A) 30-70 mass% and a polymer block (B) 70-30 mass%. When the mass ratio of the polymer block (B) is less than 2%, the pressure-sensitive adhesive composition is not preferable because of low adhesiveness. Further, when the mass ratio of the polymer block (B) is more than 77%, the block copolymer becomes a bale-like product, and it is difficult to handle the block copolymer and the pressure-sensitive adhesive using the block copolymer. Become.

  The block copolymer used in the present invention can be processed into a form that is easy to handle. For example, the polymer is pelletized by a device in which an underwater cutter or a center hot cutter device is connected to a twin-screw extruder. It can be processed into a form and provided. Moreover, after cooling the strand which comes out of a twin-screw extruder, it can also cut with a strand cutter and can obtain a pellet. The polymer processed into these pellet forms can be quantitatively fed by a pellet feeder, and the production efficiency of an adhesive and an adhesive product can be increased.

  In the pressure-sensitive adhesive composition of the present invention, when a tackifying resin is blended, the tack, adhesive force and holding force can be easily adjusted. Examples of the tackifying resin include natural resins such as rosin resins and terpene resins; petroleum resins, hydrogenated (hereinafter sometimes referred to as “hydrogenated”) petroleum resins, styrene resins, and coumarone-indene resins. And synthetic resins such as phenolic resins and xylene resins.

  Examples of the rosin-based resin include rosins such as gum rosin, tall oil rosin, and wood rosin; modified rosins such as hydrogenated rosin, disproportionated rosin, and polymerized rosin; Examples include rosin esters.

Examples of the terpene resin include terpene resins mainly composed of α-pinene, β-pinene, dipentene, etc., aromatic modified terpene resins, hydrogenated terpene resins, terpene phenol resins, and the like.
As the (hydrogenated) petroleum resin, for example, (hydrogenated) aliphatic _{(C 5} series) petroleum resin, (hydrogenated) aromatic _{(C 9} series) petroleum resin, (hydrogenated) copolymeric ( C 5 _/ C ₉ series) petroleum resin, (hydrogenated) dicyclopentadiene-based petroleum resin, alicyclic saturated hydrocarbon resins.
Examples of the styrene resin include poly α methyl styrene, α methyl styrene / styrene copolymer, styrene monomer / aliphatic monomer copolymer, styrene monomer / α methyl styrene / aliphatic monomer copolymer. Styrene monomer copolymer, styrene monomer / aromatic monomer copolymer, and the like.

  Among the above tackifying resins, terpene resins, rosin resins, (hydrogenated) petroleum resins and styrene resins are preferable in terms of expressing high adhesive strength, and particularly in terms of excellent heat resistance and transparency. Hydrogenated) petroleum resins and styrenic resins are more preferred. These may be used alone or in combination of two or more. Moreover, about the softening point of the said tackifying resin, the thing of 50 to 150 degreeC is preferable from the point which expresses high adhesive force.

  The solubility parameter value of the tackifying resin that can be used in the present invention is 8.0 to 11.0 from the viewpoint of achieving both adhesive properties and high water resistance as an adhesive composition, and 8.0 to 10.4. It is preferable that it is 8.5 to 9.4.

  Examples of the method for determining the solubility parameter value of the tackifying resin include, for example, a method of calculating from physical properties such as heat of evaporation, refractive index, Kauri-butanol number, surface tension, and dipole efficiency, Fedors equation, and Small equation. And a method of calculating from a chemical composition using the Hoy equation, a method of measuring by a solubility test in a solvent whose solubility parameter value is known, and a turbid point titration method. Among them, a method of actually measuring by a solubility test is preferable because it can be applied even when the chemical structure is not single or unknown.

  Specifically, when the tackifier resin is soluble in a solvent having a solubility parameter value of X, the solubility parameter value is insoluble in a solvent of Y, and Y is a value greater than X, The solubility parameter value of the tackifier resin can be determined from X to Y by rounding off the second decimal place. In addition, a publicly known literature value can be adopted as a solubility parameter value of a solvent to be used, for example, a value described in Journal of Paint Technology, 42 (541), pages 76 to 118 (1970). Can do.

  When the solubility parameter value is actually measured by a solubility test, the solvent to be used is preferably selected from hydrocarbon compounds, aromatic compounds, ester compounds, ketone compounds, and nitrile compounds, and has functional protons such as alcohols and amines. A solvent containing a group is not preferable because the solubility is changed by hydrogen bonding.

  The compounding amount of the tackifier resin can be appropriately selected according to the use of the pressure-sensitive adhesive, the type of adherend, etc., but in the pressure-sensitive adhesive composition from the viewpoint of improving the adhesion and improving the coatability. 1 part by mass or more and 400 parts by mass or less, and preferably 10 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of the acrylic block copolymer.

The pressure-sensitive adhesive composition of the present invention may contain various plasticizers as necessary. Examples of such plasticizers include phthalates such as dibutyl phthalate, di n-octyl phthalate, bis-2-ethylhexyl phthalate, di n-decyl phthalate and diisodecyl phthalate. Adipates such as bis-2-ethylhexyl adipate and di-n-octyl adipate, sebacic acid esters such as bis-2-ethylhexyl sebacate and di-n-butyl sebacate, bis-2-ethylhexylase Fatty acid esters such as azelaic acid esters such as rate; Paraffins such as chlorinated paraffin; Glycols such as polypropylene glycol; Epoxy polymer plastics such as epoxidized soybean oil and epoxidized linseed oil Agents; phosphate esters such as trioctyl phosphate and triphenyl phosphate; triphenyl phosphate Phosphorous esters such as acetate; ester oligomers such as esterified product of adipic acid and 1,3-butylene glycol; n-butyl poly (meth) acrylate, 2-ethylhexyl poly (meth) acrylate Acrylic oligomers such as polybutene, polyisobutylene, polyisoprene, process oil, naphthenic oil, and the like, which are used alone or in a mixture. The amount of the plasticizer used is generally 80% by mass or less of the plasticizer in the pressure-sensitive adhesive composition.
The pressure-sensitive adhesive composition of the present invention may contain various additives as necessary. Examples of such additives include antioxidants and ultraviolet absorbers for further improving weather resistance, heat resistance, and oxidation resistance; inorganic powder fillers such as calcium carbonate, titanium oxide, mica, and talc; glass Examples thereof include fibrous fillers such as fibers and organic reinforcing fibers.

  The method for producing the pressure-sensitive adhesive composition of the present invention is not particularly limited. For example, each component is mixed or kneaded in a known manner such as a kneader kneader, an extruder, a mixing gall, and a banbury mixer. Using an apparatus, it can manufacture normally by mixing at the temperature within the range of 100 to 250 degreeC. Moreover, after dissolving each component in an organic solvent and mixing, you may manufacture by distilling off this organic solvent.

  As an adhesive product obtained by forming an adhesive layer comprising the adhesive composition of the present invention on a substrate, an adhesive sheet (including an adhesive film), an adhesive tape, a pressure sensitive tape, Examples include masking tapes, electrical insulating tapes, laminate films, medical poultices, decorative adhesive sheets, and adhesive optical films.

  Paper, paper board, cellophane, organic polymer film sheet having a film shape, sheet shape, tape shape or other desired shape after the pressure-sensitive adhesive composition of the present invention is melted The adhesive product described above can be produced by cooling after coating on a substrate such as cloth, wood or metal. In addition, the pressure-sensitive adhesive composition of the present invention can be dissolved in a solvent such as toluene to form a solution and used as a solvent-type pressure-sensitive adhesive. A product may be manufactured.

  Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to the following examples.

  The synthesis of the block copolymers used in Examples and Comparative Examples was carried out by the following Synthesis Examples and Comparative Synthesis Examples using chemicals dried and purified by a conventional method. At that time, measurement of the polymerization conversion rate and analysis of the synthesized block copolymer were carried out by the following methods.

(1) Number average molecular weight (Mn), weight average molecular weight (Mw), molecular weight distribution (Mw / Mn) measuring apparatus by gel permeation chromatography (GPC): Gel permeation chromatograph (HLC-8020) manufactured by Tosoh Corporation
Column: TSKgel GMHXL, G4000HXL and G5000HXL manufactured by Tosoh Corporation connected in series Eluent: Tetrahydrofuran Eluent Flow rate: 1.0 ml / min Column temperature: 40 ° C.
Detector: Differential refractive index (RI) meter Calibration curve: Calibration using standard polystyrene

(2) Apparatus for measuring the content of each copolymer component in a copolymer by proton nuclear magnetic resonance ( ¹ H-NMR) spectroscopy: JEOL nuclear magnetic resonance apparatus (JNM-LA400)
Solvent: deuterated chloroform

(3) Measuring device for conversion rate of charged monomer by gas chromatography (GC): Gas chromatograph GC-14A manufactured by Shimadzu Corporation
Column: GL Sciences Inc. INERT CAP 1 (df = 0.4 μm, 0.25 mm ID × 60 m)
Analysis conditions: injection 300 ° C., detector 300 ° C., 60 ° C. (0 min hold) → 5 ° C./min→100° C. (0 min hold) → 15 ° C./min→300° C. (2 min hold)

[Synthesis Example 1] Synthesis of Block Copolymer 1 After attaching a three-way cock to a 2 L three-necked flask and replacing the inside with nitrogen, 868 g of toluene, N, N, N ′, N ″, N ″ − at room temperature Add 60.0 g of a toluene solution containing 3.80 g of pentamethyldiethylenetriamine and 40.2 mmol of isobutylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum, and further add 7.03 mmol of sec-butyllithium. 4.13 g of a mixed solution of cyclohexane and n-hexane contained was added. Subsequently, 39.0 g of methyl methacrylate (1) was added thereto. The reaction solution was initially colored yellow, but became colorless after stirring for 60 minutes at room temperature. At this point, 1 g of the reaction solution was collected for analysis in a sampling container containing a small amount of methanol. As a result of GC measurement of the reaction solution, the conversion rate of methyl methacrylate was 100%. Subsequently, the internal temperature of the polymerization solution was cooled to −30 ° C., and 234 g of 2-ethylhexyl acrylate was added dropwise over 2 hours. After completion of dropping, 1 g of the reaction solution was collected in a sampling container containing a small amount of methanol. As a result of GC measurement of the reaction solution, the conversion rate of 2-ethylhexyl acrylate was 100%. Subsequently, 39.0 g of methyl methacrylate (2) was added thereto, and after stirring overnight at room temperature, 3.5 g of methanol was added to terminate the polymerization reaction. As a result of GC measurement of the reaction solution, the conversion rate of methyl methacrylate was 100%. The obtained reaction solution was poured into a beaker containing 10 L of methanol to obtain a precipitate. This was vacuum-dried overnight at 60 ° C. to obtain 309 g of a white powdery polymer. This is designated as Polymer 1.

As a result of ¹ H-NMR measurement and GPC measurement of the reaction solution and the polymer 1 collected during the reaction, the polymer 1 finally obtained was polymethyl methacrylate-b-polyacrylate 2-ethylhexyl- b-polymethyl methacrylate triblock copolymer, Mn of polymethyl methacrylate block portion collected during the reaction is 6,300, Mw is 7,030, and Mw / Mn is 1.10. In addition, Mn of polymethyl methacrylate-b-polyacrylate 2-ethylhexyl collected during the reaction is 42,300, Mw is 43,800, and Mw / Mn is 1.04. Mn of the finally obtained triblock body was 48,000, Mw was 50,200, and Mw / Mn was 1.05. The proportion of each block is polymethyl methacrylate (12.5% by mass) -b-polyacrylic acid 2-ethylhexyl (75.0% by mass) -b-polymethyl methacrylate (12.5% by mass). found.

[Synthesis Example 2] Synthesis of Block Copolymer 2 After a three-way cock was attached to a 2 L three-necked flask and the inside was replaced with nitrogen, 868 g of toluene, 1,1,4,7,10,10-hexamethyltrimethyl at room temperature Add 34.8 g of toluene solution containing 1.88 g of ethylenetetramine and 23.3 mmol of isobutylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum, and further contain 7.76 mmol of sec-butyllithium. 4.56 g of a mixed solution of cyclohexane and n-hexane was added. Subsequently, 67.2 g of methyl methacrylate (1) was added thereto. The reaction solution was initially colored yellow, but became colorless after stirring for 60 minutes at room temperature. At this point, 1 g of the reaction solution was collected for analysis in a sampling container containing a small amount of methanol. As a result of GC measurement of the reaction solution, the conversion rate of methyl methacrylate was 100%. Subsequently, the internal temperature of the polymerization solution was cooled to −30 ° C., and 312.8 g of 2-ethylhexyl acrylate was added dropwise over 2 hours. After completion of dropping, 1 g of the reaction solution was collected in a sampling container containing a small amount of methanol. As a result of GC measurement of the reaction solution, the conversion rate of 2-ethylhexyl acrylate was 100%. Subsequently, 67.2 g of methyl methacrylate (2) was added thereto, and after stirring for 2 hours at room temperature, 3.5 g of methanol was added to terminate the polymerization reaction. As a result of GC measurement of the reaction solution, the conversion rate of methyl methacrylate was 100%. The obtained reaction solution was poured into a beaker containing 10 L of methanol to obtain a precipitate. This was vacuum-dried at 60 ° C. overnight to obtain 440 g of a white powdery polymer. This is designated as Polymer 2.

As a result of ¹ H-NMR measurement and GPC measurement of the reaction solution collected during the reaction and the polymer 2, the polymer ¹ finally obtained was polymethyl methacrylate-b-polyacrylic acid 2-ethylhexyl- b-polymethyl methacrylate triblock copolymer, Mn of polymethyl methacrylate block part collected during the reaction is 9,850, Mw is 11,000, and Mw / Mn is 1.12. In addition, Mn of polymethyl methacrylate-b-polyacrylate 2-ethylhexyl collected during the reaction is 51,000, Mw is 51,900, and Mw / Mn is 1.02. Mn of the finally obtained triblock body was 59,000, Mw was 60,600, and Mw / Mn was 1.03. The proportion of each block is polymethyl methacrylate (15.5% by mass) -b-polyethyl acrylate 2-ethylhexyl (69.0% by mass) -b-polymethyl methacrylate (15.5% by mass). found.

[Synthesis Example 3] Synthesis of Block Copolymer 3 A 3-L three-necked flask was fitted with a three-way cock, and the inside was replaced with nitrogen, and then 1040 g of toluene, 1,1,4,7,10,10-hexamethyltrimethyl at room temperature. Add 52.9 g of a toluene solution containing 2.45 g of ethylenetetramine and 35.5 mmol of isobutylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum, and then add 7.8.87 mmol of sec-butyllithium. A mixed solution of cyclohexane and n-hexane containing 5.20 g was added. Subsequently, 71.8 g of methyl methacrylate (1) was added thereto. The reaction solution was initially colored yellow, but became colorless after stirring for 60 minutes at room temperature. At this point, 1 g of the reaction solution was collected for analysis in a sampling container containing a small amount of methanol. As a result of GC measurement of the reaction solution, the conversion rate of methyl methacrylate was 100%. Subsequently, the internal temperature of the polymerization solution was cooled to −30 ° C., and 468 g of 2-ethylhexyl acrylate was added dropwise over 3 hours. After completion of dropping, 1 g of the reaction solution was collected in a sampling container containing a small amount of methanol. As a result of GC measurement of the reaction solution, the conversion rate of 2-ethylhexyl acrylate was 100%. Subsequently, 71.8 g of methyl methacrylate (2) was added thereto, and after stirring at room temperature for 2 hours, 3.5 g of methanol was added to terminate the polymerization reaction. As a result of GC measurement of the reaction solution, the conversion rate of methyl methacrylate was 100%. The obtained reaction solution was poured into a beaker containing 15 L of methanol to obtain a precipitate. This was vacuum-dried at 60 ° C. overnight to obtain 610 g of a white powdery polymer. This is designated as Polymer 3.

As a result of ¹ H-NMR measurement and GPC measurement of the reaction solution collected during the reaction and the polymer 3, the finally obtained polymer 3 was polymethyl methacrylate-b-polyacrylic acid 2-ethylhexyl- b-polymethyl methacrylate triblock copolymer, Mn of polymethyl methacrylate block portion collected during the reaction is 8,200, Mw is 9,400, and Mw / Mn is 1.14. In addition, Mn of polymethyl methacrylate-b-polyacrylate 2-ethylhexyl collected during the reaction is 51,000, Mw is 54,000, and Mw / Mn is 1.06. Mn of the finally obtained triblock body was 60,000, Mw was 64,000, and Mw / Mn was 1.08. The proportion of each block is polymethyl methacrylate (11.5% by mass) -b-polyethyl 2-ethylhexyl acrylate (76.5% by mass) -b-polymethyl methacrylate (12.0% by mass). found.

Comparative Synthesis Example 1 Synthesis of Block Copolymer 4 305 g of a polymer was obtained in the same manner as in Synthesis Example 1 except that 2-ethylhexyl acrylate was changed to n-butyl acrylate. This is designated as Polymer 4.

As a result of ¹ H-NMR measurement and GPC measurement of the reaction solution and the polymer 4 collected during the reaction, the finally obtained polymer 4 was polymethyl methacrylate-b-polyacrylate n-butyl- b-polymethyl methacrylate triblock copolymer, Mn of polymethyl methacrylate block portion collected during the reaction is 6,700, Mw is 7,300, and Mw / Mn is 1.09. The Mn of polymethyl methacrylate-b-polyacrylate n-butyl collected during the reaction is 58,000, Mw is 61,000, and Mw / Mn is 1.05. Mn of the obtained triblock body was 64,900, Mw was 68,100, and Mw / Mn was 1.03. The ratio of each block is polymethyl methacrylate (12.5% by mass) -b-poly (n-butyl acrylate) (75.0% by mass) -b-polymethyl methacrylate (12.5% by mass). found.

[Comparative Synthesis Example 2] Synthesis of block copolymer 5 435 g of a polymer was obtained in the same manner as in Synthesis Example 2 except that 2-ethylhexyl acrylate was changed to n-butyl acrylate. This is designated as Polymer 5.

As a result of ¹ H-NMR measurement and GPC measurement of the reaction solution and the polymer 5 collected during the reaction, the finally obtained polymer 5 was polymethyl methacrylate-b-polyacrylate n-butyl- b- Polymethyl methacrylate triblock copolymer, Mn of polymethyl methacrylate block portion collected during the reaction is 9,720, Mw is 10,400, and Mw / Mn is 1.07. In addition, Mn of polymethyl methacrylate-b-polyacrylate n-butyl collected during the reaction is 61,100, Mw is 67,200, and Mw / Mn is 1.10. The Mn of the finally obtained triblock body was 69,600, Mw was 76,900, and Mw / Mn was 1.11. The ratio of each block is polymethyl methacrylate (14.9% by mass) -b-poly (n-butyl acrylate) (70.2% by mass) -b-polymethyl methacrylate (14.9% by mass). found.

Comparative Synthesis Example 3 Synthesis of Block Copolymer 6 600 g of a polymer was obtained in the same manner as in Synthesis Example 3 except that 2-ethylhexyl acrylate was changed to n-butyl acrylate. This is designated as Polymer 6.

As a result of ¹ H-NMR measurement and GPC measurement of the reaction solution and the polymer 6 collected during the reaction, the finally obtained polymer 6 was polymethyl methacrylate-b-polyacrylate n-butyl- b-polymethyl methacrylate triblock copolymer, Mn of polymethyl methacrylate block portion collected during the reaction is 7,600, Mw is 8,800, and Mw / Mn is 1.15. In addition, Mn of polymethyl methacrylate-b-polyacrylate n-butyl collected during the reaction is 61,400, Mw is 69,100, and Mw / Mn is 1.13. Mn of the obtained triblock body was 64,000, Mw was 76,100, and Mw / Mn was 1.19. The ratio of each block is polymethyl methacrylate (11.9% by mass) -b-poly (n-butyl acrylate) (76.2% by mass) -b-polymethyl methacrylate (11.9% by mass). found.

The tackifier resins used in the examples and comparative examples are described below.
Product name “Recatac F105” manufactured by Rika Finetech Co., Ltd .: Hydrogenated rosin ester-based resin Product name “Rekatak F85” manufactured by Rika Finetech Co., Ltd .: Hydrogenated rosin ester-based resin Product name “Arcon P100” manufactured by Arakawa Chemical Industries: Alicyclic Arokawa Chemical Industry Co., Ltd .: Alicyclic saturated hydrocarbon resin trade name “KE311” Arakawa Chemical Industries, Ltd .: Special rosin ester resin trade name “Super Ester A115” Arakawa Chemical Industries, Ltd. Manufactured by: Special rosin ester resin brand name “Marcarez H505” Maruzen Petrochemical Co., Ltd .: Hydrogenated petroleum resin brand name “Ligalite R100” Eastman Chemical Co., Ltd .: Hydrogenated alicyclic saturated hydrocarbon resin brand name “Clearon M105” Yasuhara Chemical Product: Hydrogenated terpene resin

  In Examples and Comparative Examples, the production of adhesive tape and evaluation of various physical properties were performed by the methods shown below.

(1) Adhesive tape creation method:
A block copolymer and a tackifying resin having a blending mass ratio shown in Tables 1 and 3 were dissolved in toluene to prepare a 40% by weight concentration adhesive toluene solution, and a polyethylene terephthalate film was coated on the film. After coating, the film was dried and heat-treated at 160 ° C. for 30 minutes to prepare a tape for evaluating adhesive properties. In the evaluation of the produced tape, when it was necessary to affix to the adherend, the reciprocation was performed by reciprocating a 2 kg roller at a speed of 10 mm / min, and the evaluation was performed after storing at room temperature for 24 hours.

(2) Holding power test:
The measurement was performed according to JIS Z0237. That is, the produced adhesive tape was affixed to a stainless steel (SUS304) plate at 25 mm × 25 mm, and then the sample was stored at room temperature for 24 hours, and then a load of 1 kg was suspended at 120 ° C. to determine the drop time.

(3) Holding power test under high humidity:
The prepared adhesive tape was affixed to a stainless steel (SUS304) plate at 25 mm × 25 mm, and after storing the sample at room temperature for 24 hours, a load of 500 g was suspended at a temperature of 80 ° C. and a humidity of 90%. The length of the deviation was measured.

(4) 180 ° peel adhesion test:
The measurement was performed according to JIS Z0237. That is, the prepared adhesive tape having a width of 25 mm and a length of 100 mm was attached to a stainless steel (SUS304) plate and a polyethylene sheet having a thickness of about 1 mm, and then the sample was stored at room temperature for 24 hours. The measurement was performed by peeling in the direction of 180 ° at a speed of 300 mm / min.

(5) Measurement of shear bond failure temperature (SAFT):
Measured according to ASTM D4498. That is, the produced adhesive tape was cut into a width of 25 mm, and a portion to be clamped later was left and attached to a stainless steel (SUS304) plate with a size of 25 mm × 25 mm. Placed in oven and clamped 500g weight. The oven temperature is then increased from 40 ° C. to 220 ° C. at a rate of 30 ° C./hour. The temperature at which the weight dropped from the sample was recorded.

(6) Compatibility test with tackifying resin:
A block copolymer and a tackifying resin having a blending mass ratio shown in Table 2 were dissolved in toluene to prepare a 40% by weight concentration adhesive toluene solution, and a cast sheet having a thickness of about 1 mm was prepared. From the transparency of the obtained cast sheet and the presence or absence of tensile whitening phenomenon, etc.
A: Transparent and without tensile whitening;
○: Slightly transparent with tensile whitening;
Δ: Opaque and tensile whitening;
×: separated into macros;
The compatibility was evaluated based on the above criteria.

(7) Water resistance evaluation (water immersion test and haze measurement):
A block copolymer and a tackifier resin having a blending mass ratio shown in Table 3 were dissolved in toluene to prepare a 40% by weight concentration adhesive toluene solution, and the solvent was distilled off under reduced pressure to obtain an adhesive composition. It was hot-pressed at 200 ° C. to produce a 20 cm × 20 cm × 1 mm press sheet. First, the haze of the press sheet was measured. Next, the press sheet was immersed in distilled water at room temperature for 90 minutes or 17 hours, and the haze of the press sheet after immersion was measured. The haze was measured according to JIS K7136.

(8) Calculation method of solubility parameter value of tackifier resin:
It calculated | required by the melt | dissolution test which mixes 10 mass parts tackifying resin with 90 mass parts solvent at room temperature for 24 hours. When the tackifier resin is soluble in a solvent having a solubility parameter value of X, the solubility parameter value is insoluble in a solvent of Y, and Y is a value greater than X, the solubility of the tackifier resin Parameter values were defined as XY. In addition, the value described in the nonpatent literature 2 was employ | adopted for the solubility parameter value of each solvent. The results of the dissolution test and solubility parameter values are shown in Table 1.

  In Tables 2 to 6, the blend compositions of Examples 1 to 3, Examples 4 to 9, and Example 10 correspond to the blend compositions of Comparative Examples 1 to 3, Comparative Examples 4 to 9, and Comparative Example 10, respectively. To do.

[Examples 1 to 3], [Reference Examples 1 and 2]
An adhesive composition containing a block copolymer 1 or a block copolymer 2 and a tackifier resin having a low solubility parameter value was evaluated in the examples. Table 2 shows the composition and evaluation results.

[Comparative Examples 1 to 3], [Comparative Reference Examples 1 and 2]
Evaluation of the pressure-sensitive adhesive composition containing the block copolymer 4 or the block copolymer 5 and blending a tackifier resin having a low solubility parameter value in the comparative example was performed. Table 3 shows the composition and evaluation results.

[Examples 4 to 9], [Reference Examples 3 and 4]
The compatibility of the pressure-sensitive adhesive composition containing the block copolymer 1 and the tackifying resin was evaluated. Table 4 shows the composition and evaluation results.

[Comparative Examples 4 to 9], [Comparative Reference Examples 3 and 4]
The compatibility of the pressure-sensitive adhesive composition containing the block copolymer 4 and the tackifying resin was evaluated. Table 5 shows the composition and evaluation results.

[Example 10], [Reference Examples 5 and 6]
The pressure-sensitive adhesive composition containing the block copolymer 3 and blended with a tackifying resin having a low solubility parameter value in the examples was evaluated. Table 6 shows the composition and evaluation results.

[Comparative Example 10], [Comparative Reference Examples 5 and 6]
The adhesive composition containing the block copolymer 6 and blended with a tackifier resin having a low solubility parameter value in the comparative example was evaluated. Table 6 shows the composition and evaluation results.

  As can be seen from the results in Table 2, it can be seen that the pressure-sensitive adhesive of the present invention is particularly excellent in cohesive force and transparency at high temperatures. Moreover, when the tackifier resin prescribed | regulated by this invention is mix | blended, the adhesive with balance in adhesive force and adhesive force can be obtained. Example 2 and Example 3 are characterized by high adhesive strength, high transparency and high holding power at high temperatures, as compared with Comparative Example 2 and Comparative Example 3 of the corresponding composition in Table 3. You can see that it has.

  Moreover, as can be seen from the results in Table 4, the block copolymer used in the pressure-sensitive adhesive of the present invention is compatible with many types of tackifying resins. In the case of the present invention, a petroleum resin-based tackifier resin that has been difficult to be blended due to low compatibility with the base polymer of an acrylic pressure-sensitive adhesive can be blended. This means that it is possible to design a pressure-sensitive adhesive composition by selecting a suitable one from many types of tackifying resins. In addition to adhesive physical properties such as adhesive strength and cohesive strength, hue and odor Facilitates response to various market requirements across raw material costs.

  Furthermore, as can be seen from the results in Table 6, the pressure-sensitive adhesive composition of the present invention has a high cohesive force even under high humidity, and transparency is not impaired even under conditions immersed in water. It can be seen that the water resistance is excellent.

As described above, the pressure-sensitive adhesive composition of the present invention includes a specific acrylic block copolymer and has excellent weather resistance, heat resistance, water resistance, and transparency. INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a pressure-sensitive adhesive and a pressure-sensitive adhesive product that can have excellent pressure-sensitive adhesive performance over a long period of time even under an environment exposed to ultraviolet rays or under a use environment condition of high temperature and high humidity. Moreover, the specific acrylic block copolymer used by this invention can be supplied with the form excellent in the handleability, such as a pellet, and can improve the manufacture efficiency of an adhesive.

Claims (5)

At least one polymer block (A) comprising 23 to 98% by mass of a methacrylic acid alkyl ester unit and at least one polymer block comprising an acrylic acid alkyl ester unit having 6 to 18 carbon atoms in the alkyl group ( B) 100 parts by mass of an acrylic block copolymer having 77 to 2% by mass, a weight average molecular weight of 5,000 to 1,000,000, and a molecular weight distribution of 1.0 to 1.5; And 1 to 400 parts by mass of a tackifier resin having a solubility parameter value of 8.0 to 11.0;
A pressure-sensitive adhesive composition containing   The pressure-sensitive adhesive composition according to claim 1, wherein the acrylic block copolymer is produced by anionic polymerization in the presence of an organoaluminum compound.   The pressure-sensitive adhesive composition according to claim 1, wherein the tackifier resin has a solubility parameter value of 8.0 to 10.4.   The pressure-sensitive adhesive composition according to claim 1, wherein the tackifying resin is a petroleum resin. A pressure-sensitive adhesive product comprising a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive composition according to claim 1.