JP2008050563A - Acrylic pressure-sensitive adhesive composition and pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape using the same composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an acrylic pressure-sensitive adhesive composition having excellent weather resistance and transparency which are characteristics of an acrylic pressure-sensitive adhesive and excellent adhesiveness to a low-energy surface, fixing properties and heat resistance and to provide a pressure-sensitive adhesive sheet or a pressure-sensitive adhesive tape obtained by coating the acrylic pressure-sensitive adhesive composition and having the excellent weather resistance, transparency, adhesiveness to the low-energy surface, fixing properties and heat resistance. <P>SOLUTION: The acrylic pressure-sensitive adhesive composition comprises at least one kind of terpenic (meth)acrylate compound in which formula (1) (wherein, X represents a hydrogen atom or a methyl group) is a representative example as a monomer component of an acrylic polymer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention has excellent weather resistance and transparency, exhibits good adhesive properties to low energy surfaces such as polyolefins, cyclic polyolefins, and painted surfaces of automobiles, and further exhibits excellent heat resistance and fixability. The present invention relates to an acrylic pressure-sensitive adhesive composition.
The present invention also relates to a pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape in which this acrylic pressure-sensitive adhesive composition is applied to one side or both sides of a support.

Acrylic pressure-sensitive adhesives have excellent weather resistance and transparency, and have a good balance of the three physical properties of adhesives, so they are applied to many adhesive and adhesive products. Polyolefins such as polyethylene and polypropylene, cycloolefin polymers and cyclo There is a drawback that the adhesive strength to low-energy surfaces such as cyclic polyolefins such as olefin copolymers and painted surfaces of automobiles is weak.
In addition, with the recent expansion of the electronics field, new adhesives such as bonding of optical components that make up liquid crystal displays and plasma displays, special tapes used in semiconductor manufacturing processes, double-sided tapes for bonding mobile phone components, etc. Applications are born. These pressure-sensitive adhesive products are increasingly required to have higher heat resistance and fixing properties in addition to the three physical properties of the pressure-sensitive adhesive.

In order to eliminate these drawbacks and satisfy new requirements, a method of blending and modifying a tackifier resin is known (Reference 1).
However, adding a tackifying resin to an acrylic adhesive is effective in improving tackiness, heat resistance, and fixability on low-energy surfaces, but tackifying resins are generally more weather resistant than acrylic adhesives. Therefore, the adverse effect of reducing the weather resistance characteristic of the acrylic pressure-sensitive adhesive occurs. Further, when the compatibility between the acrylic pressure-sensitive adhesive and the tackifying resin is poor, the tackifying resin bleeds out to the surface of the pressure-sensitive adhesive over time, causing problems such as a decrease in tackiness and cloudiness.

On the other hand, the adhesiveness to the adherend on the low energy surface by copolymerizing a long-chain alkyl acrylic monomer having 15 to 20 carbon atoms in the alkyl group of (meth) acrylic acrylic ester constituting the acrylic adhesive. Has been disclosed (Reference 2).
However, these acrylic monomers having a long-chain alkyl group generally have a low glass transition temperature (Tg) and cannot satisfy heat resistance and fixability.

Furthermore, in order to improve heat resistance and fixability, a method of copolymerizing (meth) acrylic acid alkyl ester having a high Tg, such as ethyl acrylate or butyl acrylate, is used. When the ester is copolymerized, the heat resistance and fixability are improved, but the polarity of the pressure-sensitive adhesive is increased and the adhesion to a low energy surface is poor. From the above, a pressure-sensitive adhesive composition that maintains the weather resistance and transparency of the acrylic pressure-sensitive adhesive, has excellent adhesion to a low energy surface, and has excellent heat resistance and fixability has not been found.
JP 2004-143420 A Japanese Patent Laid-Open No. 1-261479

The present invention has been made against the background of the problems of the prior art, and has excellent weather resistance and transparency, which are the characteristics of acrylic pressure-sensitive adhesives, and excellent adhesion to low-energy surfaces. It aims at providing the acrylic adhesive composition excellent in property.
Another object of the present invention is to provide a pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape excellent in weather resistance, transparency, adhesion to low-energy surfaces, fixability, and heat resistance obtained by applying the above acrylic pressure-sensitive adhesive composition. .

  As a result of intensive studies to solve such problems, an acrylic pressure-sensitive adhesive composition containing any one of the terpene (meth) acrylate compounds represented by formulas (1) to (5) as a monomer component of an acrylic polymer. It has been found that a pressure-sensitive adhesive composition having excellent adhesion to low-energy surfaces, excellent fixability, and heat resistance can be obtained without impairing weather resistance and transparency.

  Furthermore, the acrylic pressure-sensitive adhesive composition of the present invention preferably contains any one of terpene (meth) acrylate compounds represented by the following formulas (1) to (5).

上記式中、Ｘは水素原子またはメチル基を表す。

In the above formula, X represents a hydrogen atom or a methyl group.

上記式中、Ｙは水素原子またはメチル基を表す。

In the above formula, Y represents a hydrogen atom or a methyl group.

上記式中、Ｚは水素原子またはメチル基を表す。

In the above formula, Z represents a hydrogen atom or a methyl group.

上記式中、Ａは水素原子またはメチル基を表す。

In the above formula, A represents a hydrogen atom or a methyl group.

上記式中、Ｂは水素原子またはメチル基を表す。

In the above formula, B represents a hydrogen atom or a methyl group.

  This acrylic pressure-sensitive adhesive composition can be commercialized in any of a solvent type, an emulsion type, a UV curable type, and a hot melt type, and can be applied to all supports and coating processes.

  The present invention also includes a pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape obtained by applying the above acrylic pressure-sensitive adhesive composition to one or both sides of a support.

  The acrylic pressure-sensitive adhesive composition of the present invention is excellent in weather resistance and transparency, exhibits good adhesion to polyolefins such as polyethylene and polypropylene, cyclic polyolefins, and painted surfaces of automobiles, and has heat resistance and fixability. It is excellent. In addition, the pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape obtained by applying the acrylic pressure-sensitive adhesive composition of the present invention is excellent in heat resistance and fixability, and is optimal for applications in the electronics field.

  The acrylic pressure-sensitive adhesive composition of the present invention will be described. First, the terpene (meth) acrylate compounds of the formulas (1) to (5) which are constituent monomers will be described.

上記式中、Ｘは水素原子またはメチル基を表す。

In the above formula, X represents a hydrogen atom or a methyl group.

上記式中、Ｙは水素原子またはメチル基を表す。

In the above formula, Y represents a hydrogen atom or a methyl group.

上記式中、Ｚは水素原子またはメチル基を表す。

In the above formula, Z represents a hydrogen atom or a methyl group.

上記式中、Ａは水素原子またはメチル基を表す。

In the above formula, A represents a hydrogen atom or a methyl group.

上記式中、Ｂは水素原子またはメチル基を表す。

In the above formula, B represents a hydrogen atom or a methyl group.

  The terpene (meth) acrylate compound of the present invention is obtained by esterifying a terpene alcohol compound and (meth) acrylic acid, but the starting material, synthesis method, and synthesis rate are not particularly limited.

  Examples of the terpene alcohol compound include those represented by the following formulas (6) to (10), but the starting material, the synthesis method, and the synthesis rate are not particularly limited.

  The esterification method of a terpene alcohol compound and (meth) acrylic acid is a direct esterification method in which the terpene alcohol compound and (meth) acrylic acid coexist, or transesterification using various lower alcohol (meth) acrylic esters. The production method is not particularly limited, and can be carried out by a conventional esterification method such as an acid chromatography method using (meth) acrylic acid chloride.

The acrylic pressure-sensitive adhesive composition of the present invention is produced by polymerizing the terpene (meth) acrylate compounds of the above formulas (1) to (5) alone or copolymerizing with other acrylic monomer components. be able to.
The (co) polymerization method may be any of solution polymerization, emulsion polymerization, UV polymerization and the like, and is not particularly limited. The form may be any of a solvent type, an emulsion type, a hot melt type, and a UV curable type.
Here, the (co) polymerizable acrylic monomer is described, but there is no particular limitation, but specific examples include the following.

  As (meth) acrylic acid alkyl esters, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, (meth ) Isobutyl acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-pentyl (meth) acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate, (meth) acrylic Heptyl acid, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, ( (Meth) acrylic acid behenyl etc. are mentioned, and two or more kinds may be used in combination.

  (Meth) acrylic acid esters such as cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, benzyl (meth) acrylate, phenylethyl (meth) acrylate, (meth) acrylic Phenoxyethyl acid, dicyclopentenyloxyethyl (meth) acrylate, phenoxydiethylene glycol ester (meth) acrylate, and the like (meth) acrylic aryl esters include phenyl (meth) acrylate, (meth) acrylic acid And methylphenyl.

  (Meth) acrylic acid, (meth) acrylic acid β-carboxyethyl, succinic acid mono (meth) acryloyloxyethyl ester, ω-carboxypolycaprolactone mono (meth) acrylate, 2- (meth) acryloyloxy as carboxyl group-containing monomers Examples thereof include ethyl hydrogen phthalate, 2- (meth) acryloyloxypropyl hydrogen phthalate, 2- (meth) acryloyloxypropyl hexahydrohydrogen phthalate, 2- (meth) acryloyloxypropyl tetrahydrohydrogen phthalate and the like. 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxy (meth) acrylate Butyl, 2-hydroxy-3-chloropropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2-hydroxy-3-allyloxypropyl (meth) acrylate, 2-acryloyloxyethyl -2-hydroxypropyl phthalate and the like.

  As ether group-containing monomers, 2-methoxyethyl (meth) acrylate, 1,3-butylene glycol methyl ether (meth) acrylate, butoxyethyl (meth) acrylate, methoxytriethylene glycol (meth) acrylate, methoxypolyethylene glycol # 400 (Meth) acrylate, methoxydipropylene glycol (meth) acrylate, methoxytripropylene glycol (meth) acrylate, methoxypolypropylene glycol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, 2-ethylhexyl carbitol (meth) acrylate, (meta ) Tetrahydrofurfuryl acrylate, phenoxyethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, E Bruno carboxymethyl polyethylene glycol (meth) acrylate, cresyl polyethylene glycol (meth) acrylate, p- nonyl phenoxyethyl (meth) acrylate, p- nonylphenoxy polyethylene glycol (meth) acrylate

  In addition, epoxy group-containing monomers such as glycidyl (meth) acrylate, amino group-containing monomers such as N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, morpholinoethyl (meth) acrylate, etc. , Trimethylsiloxyethyl (meth) acrylate, γ- (meth) acryloxypropyltrimethoxysilane, etc. as organosilicon group-containing monomers, diphenyl-2- (meth) acryloyloxyethyl phosphate, 2- (meth) acryloyl as phosphorus-containing monomers Oxyethyl acid phosphate, caprolactone-modified-2- (meth) acryloyloxyethyl acid phosphate, (meth) acryloyl isocyanate, 2- (meta Acryloyloxyethyl isocyanate and the like.

  In the (co) polymerization method, any copolymer component can be used in addition to the terpene (meth) acrylate compound and the other acrylic monomer, which are the essential polymerization components of the present invention. Such optional copolymerization components include styrenes such as styrene, hydroxystyrene, chlorostyrene, bromostyrene, methylstyrene, methoxystyrene, tert-butoxystyrene, tert-butoxycarbonylstyrene, tert-butoxycarbonyloxystyrene, 2,4 -Vinyl compounds such as diphenyl-4-methyl-1-pentene, α-methylstyrene, vinyl acetate, vinyl monochloroacetate, vinyl benzoate, vinyl pivalate, vinyl butyrate, vinyl laurate, divinyl adipate, vinyl methacrylate, Vinyl crotonate, vinyl 2-ethylhexanoate, N-vinyl carbazole, N-vinyl pyrrolidone, etc., allyl compounds such as allyl acetate, allyl glycidyl ether, etc. Acid, crotonic acid, fumaric acid, etc., maleic anhydride etc. as acid anhydride residue-containing monomer, vinyltrimethoxysilane, allyltrimethoxysilane, trimethoxysilylpropylallylamine, 2-methoxyethoxytrimethoxy as organosilicon group-containing monomer Acrylamide etc. are mentioned as acid amide compounds, such as silane.

  The proportion of the structural unit of the terpene (meth) acrylate compound of the present invention contained in this acrylic polymer is usually 1 to 100 mol%, preferably 3 to 90, based on the total amount including other acrylic monomers. Mol%. When the proportion of the structural unit of the terpene (meth) acrylate compound is less than 1 mol%, the adhesion to polyolefin is insufficient, which is not preferred. On the other hand, when it exceeds 90 mol%, the balance of the three physical properties of the adhesive tends to be lost. Absent.

  Here, the solvent-type acrylic pressure-sensitive adhesive composition widely used for electronic materials will be described in more detail as an example. As a manufacturing method of a solvent-type acrylic adhesive, the process of superposing | polymerizing a (meth) acrylic-type monomer in an organic solvent using a polymerization initiator is included. Organic solvents used here include ester solvents such as ethyl acetate and methyl acetate, ketone solvents such as acetone and methyl ethyl ketone, alcoholic solutions such as methanol, ethanol and butanol, and hydrocarbon solutions such as cyclohexane, hexane and heptane. , Aromatic solvents such as toluene and xylene. These organic solvents may be used alone or in a combination of two or more.

  The polymerization initiator is not particularly limited as long as a desired polymerization rate and degree of polymerization can be obtained, and general-purpose ones can be suitably used. Examples include benzoyl peroxide and azobisisobutyronitrile. The polymerization initiators may be used alone or in combination of two or more. Furthermore, a general purpose chain transfer agent can also be used as needed. The polymerization conditions such as polymerization temperature and nitrogen substitution are not particularly limited as long as a desired polymerization rate and degree of polymerization can be obtained, and ordinary polymerization conditions are used. Here, “copolymerization” in the present invention refers not only to the state of being incorporated in the polymer chain but also to the state of being bonded to the polymer terminal.

  The polystyrene-converted weight average molecular weight (Mw) of the acrylic polymer of the present invention measured by gel permeation chromatography is 5,000 to 2,000,000, preferably 5,000 to 1,000,000. If Mw is less than 5,000, the cohesive force may be insufficient, resulting in a problem that the adhesive strength and holding power of the adhesive 3 physical properties are inferior. On the other hand, if the viscosity exceeds 2,000,000, the viscosity increases, so that the coating property is lowered and the tackiness of the three physical properties of the adhesive is inferior. Moreover, the dispersity (Mw / polystyrene conversion number average molecular weight) of the (co) polymer is preferably 1 to 20, more preferably 5 to 20, and particularly preferably 5 to 10.

In the acrylic pressure-sensitive adhesive composition of the present invention, a crosslinking agent is preferably blended with the acrylic polymer. An acrylic pressure-sensitive adhesive composition containing a cross-linking agent has increased cohesive strength and increased temperature sensitivity at high and low temperatures.
As a crosslinking agent for crosslinking an acrylic polymer, a functional group having the reactivity with the functional group introduced into the acrylic polymer which is the functional group of the above-described functional group-containing acrylic monomer is contained in one molecule. A compound having two or more compounds can be used. Examples of such functional groups include isocyanate groups, epoxy groups, amino groups, methylol groups, alkoxymethyl groups, imino groups, metal chelate groups, aziridinyl groups, and the like.
Specific examples of the compound include a polyfunctional isocyanate compound, a polyfunctional epoxy compound, a polyfunctional melamine compound, a metal crosslinking agent, and an aziridine compound.

  Polyfunctional isocyanate compounds having two or more isocyanate groups include tolylene diisocyanate (TDI), 4,4′-diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate, xylylene diisocyanate, metaxylylene diisocyanate, 1,5-naphthalene. Diisocyanate compounds such as diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate, and isophorone diisocyanate; Bullet polyisocyanate compounds such as “Sumijour N” (manufactured by Sumitomo Bayer Urethane Co., Ltd.); IL ”,“ Death Module HL ”(all manufactured by Bayer AG),“ Coronate EH ”(manufactured by Nippon Polyurethane Industry Co., Ltd.) Polyisocyanate compounds having an isocyanurate ring known as: Adduct polyisocyanate compounds such as “Sumijour L” (manufactured by Sumitomo Bayer Urethane Co., Ltd.); “Coronate L” and “Coronate L-55E” (both Nippon Polyurethane Industry And adduct polyisocyanate compounds such as those manufactured by K.K. These can be used alone or in combination of two or more. In addition, so-called blocked isocyanates in which the isocyanate groups of these compounds are inactivated by reacting with a masking agent having active hydrogen can also be used.

  The polyfunctional epoxy compound is not particularly limited as long as it is a compound having two or more epoxy groups per molecule. Specific examples include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, bisphenol A / epichlorohydrin type epoxy resin, N, N, N ′, N′-tetraglycidyl-m- Examples include xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N-diglycidylaniline, N, N-diglycidyltoluidine, and the like.

  The polyfunctional melamine compound is not particularly limited as long as it is a compound having a total of two or more methylol groups, alkoxymethyl groups or imino groups per molecule. Specific examples include hexamethoxymethyl melamine, hexaethoxymethyl melamine, hexapropoxymethyl melamine, hexabutoxymethyl melamine, hexapentyloxymethyl melamine and the like.

  The metal crosslinking agent is not particularly limited. Specific examples include metals such as aluminum, zinc, cadmium, nickel, cobalt, copper, calcium, barium, titanium, manganese, iron, lead, zirconium, chromium, tin, acetylacetone, methyl acetoacetate, ethyl acetoacetate, lactic acid. Examples thereof include metal chelate compounds coordinated with ethyl, methyl salicylate, and the like.

  Examples of the aziridine compound include N, N′-hexamethylene-1,6-bis (1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, bisisophthaloyl-1- (2 -Methylaziridine), tri-1-aziridinyl phosphine oxide, N, N′-diphenylethane-4,4′-bis (1-aziridinecarboxamide) and the like.

  Although the usage-amount of a crosslinking agent is not specifically limited, It is preferable that a crosslinking agent shall be 0.05-15 mass% with respect to an acrylic polymer (solid content). If it is less than 0.05% by mass, the crosslinking is insufficient, the crosslinking density is low, and the cohesive force may be insufficient. If it exceeds 15% by mass, the crosslinking density may become too high and the adhesive strength may be lowered. A more preferable lower limit is 0.1% by mass, and an upper limit is 10% by mass.

  If necessary, the acrylic pressure-sensitive adhesive composition may be blended with other acrylic (co) polymers and tackifiers to such an extent that the characteristic weather resistance and transparency are not lowered. Tackifiers include (polymerized) rosin, (polymerized) rosin ester, terpene, terpene phenol, coumarone, coumarone indene, styrene resin, xylene resin, phenol resin, petroleum resin, etc. Is mentioned. These can be used alone or in combination.

  Although the quantity of a tackifier is not specifically limited, It is usually preferable to set it as 5-100 mass parts with respect to 100 mass parts of acrylic polymers. When the addition amount of the tackifier is less than 5 parts by mass, the effect of improving the tackiness by the tackifier may not be exhibited. On the other hand, when the addition amount of the tackifier is more than 100 parts by mass, there is a possibility that tack is reduced and the adhesive strength is reduced. More preferably within the range of 10-50 parts by mass.

  Furthermore, conventionally known additives such as fillers, pigments, diluents, anti-aging agents, UV absorbers, UV stabilizers, antistatic agents, etc., are usually added to the acrylic pressure-sensitive adhesive composition as necessary. May be added. These additives can be used alone or in combination of two or more.

  A pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape can be obtained by applying the acrylic pressure-sensitive adhesive composition of the present invention to one or both sides of a support and providing a layer. The support used here is not particularly limited, and for example, in addition to a plastic film, paper, and nonwoven fabric, a sheet such as a metal foil, a plastic or rubber foam, or a tape-like material can be applied.

  Although it does not specifically limit as a method of processing an acrylic adhesive composition to the said support body, The manufacturing method of a solvent-type acrylic adhesive is mentioned as an example below. An organic solvent, for example, a mixed solution of toluene and ethyl acetate, an acrylic polymer and the like is stirred and dissolved to prepare an adhesive solution having a solid content of 10 to 70% by weight. The pressure-sensitive adhesive tape or pressure-sensitive adhesive sheet of the present invention can be obtained by applying the acrylic pressure-sensitive adhesive composition thus prepared to a support using, for example, a roll coater or a reverse coater and volatilizing the solvent by heating. The thickness of the pressure-sensitive adhesive layer is not particularly limited, but is usually about 0.01 to 1.0 mm.

  The pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape obtained by applying the acrylic pressure-sensitive adhesive composition of the present invention to a support is excellent in adhesion to a low energy surface without impairing weather resistance and transparency, and further, fixability and heat resistance. Is excellent.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited to these. In addition, unless otherwise indicated, the part and% in an Example and a comparative example are a basis of weight.

The following apparatus was used for the analysis in the following Example.
1. Purity: determined by a gas chromatography mass spectrometer (GC-MS). Apparatus: Hewlett Packard, HP6890 GC System, column: HP-5MS (Crosslinked 5% Ph Me Siloxane) diameter 0.25 mm × 30 m, ionization mode: EI
2. Molecular weight: The weight average molecular weight (Mw) was determined by gel permeation chromatography (GPC). Equipment: Waters, model 510, column; Waters, Styragel (HR5 + HR4) × 2, solvent: tetrahydrofuran, standard material: polystyrene Glass transition temperature (Tg): determined by DSC measurement. Apparatus; manufactured by Shimadzu Corporation, differential scanning calorimeter DSC-60, measurement temperature; -100 to 150 ° C. (10 ° C./min), measurement environment; nitrogen atmosphere

Synthesis example 1
(Synthesis of terpene acrylate compound represented by formula (1))
In a 2,000 ml four-necked flask equipped with a Dean-Stark tube, a cooling tube, a thermometer, and a stirring rod, 176 g (1.0 mol) of a terpene alcohol compound of formula (6), 1,000 g of toluene, and 127 g of acrylic acid (1.8 mol), hydroquinone monomethyl ether 25 mg, and ion exchange resin (Amberlyst 15E, manufactured by Rohm and Haas) were charged. The mixture was refluxed at 100 ° C. for 12 hours under reduced pressure, and the resulting mixture was filtered to remove the catalyst. Subsequently, toluene was distilled off at 80 ° C. under reduced pressure, and 197.4 g of terpene acrylate compound represented by formula (1) (X in formula (1) represents a hydrogen atom) (yield 84.1%, Purity 97.5%).

Example 1
(Copolymerization of terpene acrylate compound of formula (1) with other acrylic monomers)
2-ethylhexyl acrylate, acrylic acid, 2-hydroxyethyl methacrylate, a terpene-based acrylate compound of formula (1) (X in formula (1) represents a hydrogen atom), 100: 6.0: 0.4: 100 Prepare 100g by weight, 0.2g of α, α'-azobisisobutyronitrile as polymerization initiator, 400ml of toluene / ethyl acetate as solvent, thermometer, stirrer, inert gas introduction tube, reflux condenser. The 1,000 ml four-necked flask equipped was charged. Stirring was performed while raising the temperature in the flask to 60 ° C. under a nitrogen stream, and the reaction was performed for 12 hours. The weight average molecular weight (Mw) of 432.6 g of the obtained acrylic polymer was 350,000. (Sample A)
0.5 parts of Coronate L (manufactured by Nippon Polyurethane Industry Co., Ltd.), which is an isocyanate-based crosslinking agent, was added to 100 parts of the sample A and mixed uniformly to prepare an acrylic pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition was applied to a polyethylene terephthalate (PET) film (Toray Industries, Inc .: thickness 38 μm) as a substrate so that the thickness after drying was 20 to 25 μm, and then at 100 ° C. for 3 minutes. Dried. Thereafter, a release paper (“K-80HS” manufactured by Sanei Kaken Co., Ltd.) is attached to the surface of the layer made of the pressure-sensitive adhesive composition for protection, and then the surface is 3 in an atmosphere at a temperature of 50 ° C. and a relative humidity of 65%. Cured for days.

Synthesis example 2
(Synthesis of terpene acrylate compound of formula (2))
In a 2,000 ml four-necked flask equipped with a stirrer and a reflux condenser, 156 g (1.0 mol, purity 98%) of a terpene alcohol compound of formula (7), 400 g of toluene, 0.3 g of hydroquinone, and 510.1 g (5.0 mol, purity 99%) of triethylamine was added and heated to 40 ° C. with stirring, and 142.9 g (1.5 mol, purity 95%) of acrylic acid chloride was added thereto for 3 hours. After dropwise addition, the mixture was heated and stirred at 80 ° C. for 2 hours to carry out the reaction.
After cooling, the reaction solution is poured into n-hexane, washed twice with a 5% by weight aqueous sodium hydrogen carbonate solution and twice with clean water, and then distilled under reduced pressure to obtain a terpene acrylate represented by the formula (2). 195.1 g (boiling point 126-128 ° C./1 mmHg, purity 97%) of the compound (Y in formula (2) represents a hydrogen atom) was obtained.

Example 2
(Copolymerization of terpene acrylate compound of formula (2) with other acrylic monomers)
2-ethylhexyl acrylate, acrylic acid, 2-hydroxyethyl methacrylate, terpene acrylate compound of formula (2) (Y in formula (2) represents a hydrogen atom), 150: 6.0: 0.4: 50 100 g by weight ratio, α, α′-azobisisobutyronitrile 0.2 g as a polymerization initiator, 400 ml of toluene / ethyl acetate as a solvent, thermometer, stirrer, inert gas introduction tube, reflux condenser The 1,000 ml four-necked flask equipped was charged. The mixture was stirred while raising the temperature in the flask to 60 ° C. under a nitrogen stream, and reacted for 12 hours. The weight average molecular weight (Mw) of 94.1 g of the obtained acrylic polymer was 450,000. (Sample B)
0.5 parts of Coronate L (manufactured by Nippon Polyurethane Industry Co., Ltd.) which is an isocyanate-based crosslinking agent was added to 100 parts of the sample B, and mixed uniformly to prepare an acrylic pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition was applied to a polyethylene terephthalate (PET) film (Toray Industries, Inc .: thickness 38 μm) as a base material so that the thickness after drying was 20 to 25 μm, and then at 100 ° C. for 3 minutes. Dried. Thereafter, a release paper (“K-80HS” manufactured by Sanei Kaken Co., Ltd.) is attached to the surface of the layer made of the pressure-sensitive adhesive composition for protection, and then the surface is 3 in an atmosphere at a temperature of 50 ° C. and a relative humidity of 65%. Cured for days.

Synthesis example 3
(Synthesis of terpene acrylate compound of formula (3))
Synthesis was performed in the same manner as in Synthesis Example 1 except that 176 g (1.0 mol) of the terpene alcohol compound of formula (6) was changed to 200 g (1.0 mol) of the terpene alcohol compound of formula (8). Thus, 206.4 g (yield 70%, purity 72%) of a terpene acrylate compound represented by formula (3) (Z in formula (3) represents a hydrogen atom) was obtained.

Example 3
(Copolymerization of terpene acrylate compound of formula (3) with other acrylic monomers)
In Example 2, the terpene acrylate compound of formula (2) (Y in formula (2) represents a hydrogen atom) and the terpene acrylate compound of formula (3) (Z in formula (3) represents a hydrogen atom) and Copolymerization was carried out in the same manner except that. The weight average molecular weight (Mw) of 93.4 g of the obtained acrylic polymer was 460,000. (Sample C)
Thereafter, a cross-linking agent was blended in the same manner except that Sample B was changed to Sample C in Example 2 to prepare an adhesive tape.

Synthesis example 4
(Synthesis of terpene acrylate compound of formula (4))
The synthesis was performed in the same manner as in Synthesis Example 1 except that 176 g (1.0 mol) of the terpene alcohol compound of formula (6) was changed to 200 g (1.0 mol) of the terpene alcohol compound of formula (9). Thus, 184.5 g (yield 65%, purity 70%) of a terpene acrylate compound represented by formula (4) (A in formula (4) represents a hydrogen atom) was obtained.

Example 4
(Copolymerization of terpene acrylate compound of formula (4) with other acrylic monomers)
In Example 2, a terpene acrylate compound of formula (2) (Y in formula (2) represents a hydrogen atom) and a terpene acrylate compound of formula (4) (A in formula (4) represents a hydrogen atom) and Copolymerization was carried out in the same manner except that. The weight average molecular weight (Mw) of 95.3 g of the obtained acrylic polymer was 440,000. (Sample D)
Thereafter, except that Sample B was changed to Sample D in Example 2, a cross-linking agent was blended in the same manner to prepare an adhesive tape.

Synthesis example 5
(Synthesis of terpene acrylate compound of formula (5))
The synthesis was performed in the same manner as in Synthesis Example 1 except that 176 g (1.0 mol) of the terpene alcohol compound of formula (6) was changed to 200 g (1.0 mol) of the terpene alcohol compound of formula (10). Thus, 161.9 g (yield 62%, purity 72%) of a terpene acrylate compound represented by formula (5) (B in formula (5) represents a hydrogen atom) was obtained.

Example 5
(Copolymerization of terpene acrylate compound of formula (5) with other acrylic monomers)
In Example 2, a terpene acrylate compound of formula (2) (Y in formula (2) represents a hydrogen atom) and a terpene acrylate compound of formula (5) (B in formula (5) represents a hydrogen atom) and Copolymerization was carried out in the same manner except that. The weight average molecular weight (Mw) of 89.4 g of the obtained acrylic polymer was 470,000. (Sample E)
Thereafter, a cross-linking agent was blended in the same manner as in Example 2 except that Sample B was changed to Sample E, and an adhesive tape was prepared.

Comparative Example 1
(Copolymerization of other acrylic monomers)
100 g of butyl acrylate, 2-hydroxyethyl methacrylate and acrylic acid were prepared at a weight ratio of 100: 6.0: 0.4, 0.2 g of α, α′-azobisisobutyronitrile as a polymerization initiator, 400 ml of toluene / ethyl acetate was charged into a 1,000 ml four-necked flask equipped with a thermometer, a stirrer, an inert gas introduction tube, and a reflux condenser. The mixture was stirred while raising the temperature in the flask to 60 ° C. under a nitrogen stream, and reacted for 12 hours. The weight average molecular weight (Mw) of the obtained acrylic polymer 425.2g was 516,000. (Sample F)
0.5 parts of Coronate L (manufactured by Nippon Polyurethane Industry Co., Ltd.) which is an isocyanate-based crosslinking agent was added to 100 parts of the sample F and mixed uniformly to prepare an acrylic pressure-sensitive adhesive composition.

Comparative Example 2
(Addition of tackifying resin)
100 g of 2-ethylhexyl acrylate, 2-hydroxyethyl methacrylate and acrylic acid were prepared at a weight ratio of 100: 6.0: 0.4, and 0.2 g of α, α'-azobisisobutyronitrile as a polymerization initiator, As a solvent, 400 ml of toluene / ethyl acetate was charged into a 1,000 ml four-necked flask equipped with a thermometer, a stirrer, an inert gas introduction tube, and a reflux condenser. The mixture was stirred while raising the temperature in the flask to 60 ° C. under a nitrogen stream, and reacted for 12 hours. The obtained acrylic polymer 412.4 g had a weight average molecular weight (Mw) of 504,000. (Sample G)
To 100 parts of the above sample G, add 30 parts of a polymerized rosin ester having a softening point of 125 ° C. and 0.5 part of Coronate L (manufactured by Nippon Polyurethane Industry Co., Ltd.), which is an isocyanate crosslinking agent, and mix uniformly. An acrylic pressure-sensitive adhesive composition was prepared.

<Evaluation method>
The evaluation method is as follows.
1. Adhesive strength: A polyethylene plate (PE) or a cycloolefin polymer plate (COP) is used as an adherend, and an adhesive tape sample (initial sample) is attached to the adherend in an atmosphere at a temperature of 23 ° C. and a relative humidity of 65%. After a 2 kg rubber roller was reciprocated three times and pressed, it was left for 30 minutes. Then, using an tensile tester in an atmosphere of 23 ° C. and a relative humidity of 65%, the film part of the adherend and the adhesive tape (the part where the adhesive composition is not applied) are each gripped at a speed of 300 mm / min. The strength was measured when the sample was pulled in the 180 ° direction and peeled off from the adherend.
2. Holding power: SUS304 stainless steel plate (SUS), polyethylene plate (PE), cycloolefin polymer plate (COP) as an adherend, and an adhesive tape sample (initial sample or time-lapse sample) on the adherend with an area of 25 mm × 25 mm Affixing was performed by reciprocating three 2 kg rubber rollers in an atmosphere of a temperature of 23 ° C. and a relative humidity of 65%, and left for 30 minutes. Then, it was left standing for another 30 minutes as a state suspended vertically in a holding power tester set to 40 ° C. and 70 ° C. (only SUS304 stainless steel plate was evaluated for 70 ° C.). Thereafter, a load of 1 kg was uniformly applied to the adhesive tape, and the distance that the adhesive tape was displaced after 1 hour (displacement between the position of the adhesive tape attached to the adherend after 1 hour and the initial application position; The displacement distance) and the drop time were measured.
3. Constant load: A cycloolefin polymer plate (COP) is used as an adherend, and an adhesive tape sample (initial sample or time-lapse sample) is attached to the adherend in an area of 10 mm × 50 mm, and the temperature is 23 ° C. and the relative humidity is 65%. Under the pressure, the 2 kg rubber roller was reciprocated three times and left for 30 minutes. Thereafter, the adherend to which the adhesive tape was bonded was held horizontally in a holding force tester set at 23 ° C., and the adhesive tape was suspended vertically and left for another 30 minutes. Thereafter, a 100 g load was uniformly applied to the adhesive tape for evaluation (◯: good, Δ: slightly good, x: poor).
4). Transparency: The haze of the sample was measured with COH-300A manufactured by Nippon Denshoku Industries Co., Ltd.
5. Weather resistance: A sample was put in Table Sun XT750 manufactured by Suga Test Instruments Co., Ltd., irradiated with illuminance of 48,000 lx, irradiation for 100 hours at a temperature of 50 ° C., and then yellowed with COH-300A manufactured by Nippon Denshoku Industries Co., Ltd. ΔYI value) was measured.

Industrial applicability

  An acrylic pressure-sensitive adhesive composition containing a terpene (meth) acrylate compound as a monomer component of the acrylic polymer of the present invention is a general packaging tape such as kraft tape or OPP tape, double-sided tape, medical tape, protective film. It can be used not only for labels, tack paper, but also for adhesive sheets and protective films used in the electronics field.

Claims (2)

An acrylic pressure-sensitive adhesive composition containing any one of terpene (meth) acrylate compounds represented by the following formulas (1) to (5) as a monomer component of an acrylic polymer.

In the above formula, X represents a hydrogen atom or a methyl group.

In the above formula, Y represents a hydrogen atom or a methyl group.

In the above formula, Z represents a hydrogen atom or a methyl group.

In the above formula, A represents a hydrogen atom or a methyl group.

In the above formula, B represents a hydrogen atom or a methyl group.   A pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape obtained by coating the acrylic pressure-sensitive adhesive composition according to claim 1 on one or both sides of a support.