JP2838719B2 - Active energy ray-curable pressure-sensitive adhesive composition for hot melt - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an active energy ray-curable pressure-sensitive adhesive composition for hot melt, and more particularly to an acrylic (co) polymer having a specific molecular weight. On the other hand, a specific amount of one or more compounds selected from a group of compounds having a specific molecular weight range having two or more specific ethylenically unsaturated bonds in one molecule, and one (meth) acryloyl group in one molecule and A specific amount of a compound having one tertiary amino group, a specific diene compound and / or a specific amount of a compound having one (meth) acryloyl group and (poly) oxyalkylene chain in one molecule, and And an active energy ray-curable hot melt pressure-sensitive adhesive composition comprising a specific amount of an antioxidant.

[Conventional technology and its problems]

Conventionally, many adhesives have been known for active energy ray-curable pressure-sensitive adhesives. However, these adhesives still have many problems that need to be solved.

For example, Japanese Patent Application Laid-Open No. Sho 50-136328 discloses that "alkyl acrylate (alkyl group having 3 to 10 carbon atoms) 50 to 100".
Parts by weight, 20-100 parts by weight of vinyl acetate, COOH, CN, CON on the side chain
H ₂ and is coated or impregnated with a copolymer composed mainly of vinyl monomer 3-15 parts by weight on a support sheet having a selected polar group from the group of derivatives thereof, to hold the pressure-sensitive adhesive Pressure-sensitive adhesive tape characterized by irradiating with ionizing radiation in the range of 3 to 35 Mrad to generate appropriate crosslinking "
Has been proposed.

However, in order to impart sufficient cohesive force to the pressure-sensitive adhesive layer of the “pressure-sensitive adhesive tape” in the above proposal, it is generally necessary to irradiate a relatively high dose of ionizing radiation. In many cases, the pressure-sensitive adhesiveness of the agent layer is extremely reduced, and it is easy for the pressure-sensitive adhesive tape to maintain various properties such as heat resistance, pressure-sensitive adhesiveness, adhesive strength, and cohesive force in a well-balanced manner. is not. Further, if the irradiation dose of the ionizing radiation is too large, the “support sheet” may be deteriorated, and there is a problem that the material of the support sheet is limited by itself.

Furthermore, in order to use the above-mentioned copolymer as a hot-melt pressure-sensitive adhesive, the coating must be heated to a considerably high temperature in order to secure the coating viscosity.
Problems such as thermal deterioration are likely to occur. Further, when an organic solvent is used to avoid thermal coloring and thermal deterioration, the organic solvent volatilizes into the air during coating, deteriorating the working environment and easily causing problems such as air pollution.

Next, JP-A-59-176370 discloses that "radical cross-linking to 100 parts by weight of a copolymer having a molecular weight of 100,000 to 600,000 and containing an alkyl ester of acrylic acid or methacrylic acid as a main component is carried out by ultraviolet rays or electron beams. One unsaturated bond that can cause
A pressure-sensitive adhesive composition comprising 1 to 50 parts by weight of an oligomer having a molecular weight of 1,000 to 20,000 having two or more in the molecule and 0 to 10 parts by weight of a photosensitizer and capable of being radically crosslinked by ultraviolet rays or electron beams . "Has been proposed.

However, the oligomer used in the second proposal has a molecular weight larger than the molecular weight range of the compound having "two or more specific ethylenically unsaturated bonds in one molecule" of the present invention. When the viscosity tends to be high, heating at a higher temperature is required to lower the viscosity at the time of coating, and thermal polymerization of the oligomer, thermal deterioration, etc. are easily caused, and the obtained pressure-sensitive adhesive layer is colored. In addition, it tends to be difficult to maintain the balance among the above-mentioned properties such as heat resistance, pressure-sensitive adhesiveness, adhesive strength, and cohesive strength. There is also a problem that it is difficult to reuse the composition once melted by heating.

The present inventors have conducted research to solve the problems of these conventional active energy ray-curable pressure-sensitive adhesives. As a result, for acrylic (co) polymers having a specific molecular weight,
By containing a specific amount of a compound having a specific molecular weight range having two or more ethylenically unsaturated bonds in one molecule and an antioxidant, the above problems can be solved and an excellent active energy ray-curable hot melt feeling can be obtained. We found that a pressure-sensitive adhesive composition could be obtained, and filed a patent application (Japanese Patent Application No. Hei.
No.-9965). The pressure-sensitive adhesive composition of the present invention was considerably superior to the conventional one, but a higher coating speed may be required for the purpose of higher productivity. In such a case, it is required to further lower the viscosity of the composition. Further, the pressure-sensitive adhesive composition for hot melt of the above-mentioned invention tends to have insufficient pressure-sensitive adhesiveness and adhesive strength, especially to non-polar plastics such as polyethylene, as compared with solvent-based pressure-sensitive adhesives. In addition, there is a problem in that the curved surface adhesiveness to a non-polar plastic molded product, for example, a small-diameter rod-shaped product having a diameter of about 10 to 20 mmφ or a molded product having an edge portion is not sufficient.

On the other hand, in order to reduce the viscosity of the pressure-sensitive adhesive at the time of coating, it is conventionally known to use a (meth) acrylic monomer such as n-butyl acrylate as a diluent. , in JP-a-58-108275, "the general formula CH ₂ = CHCOOR ¹ (where R ¹ is an alkyl group having 2 to 14 carbon atoms) different homopolymer or R ¹ acrylic acid ester represented by the 100 parts by weight of a copolymer of acrylic acid esters having a molecular weight of 5,000 to 300,000, and a general formula CH ₂ = CHCOOR ² (where R ² has ² carbon atoms)
Ionizing radiation-curable type, comprising as main components 5 to 40 parts by weight of a monomer represented by the following formula (1 to 14 alkyl groups) and 0.01 to 10 parts by weight of an acrylate ester having two or more acryloyl groups in one molecule. Adhesive composition. "Has been disclosed.

However, although the pressure-sensitive adhesive composition of the above proposal can lower the viscosity at the time of coating, the acrylic monomer used generally has large volatility, strong odor, and
Due to its high flammability, it significantly deteriorates the working environment at the time of coating, and also causes a problem of a change in the composition over time and a change in viscosity of the pressure-sensitive adhesive composition with the volatilization of the monomer during storage,
There are many problems such as the danger of fire and the like, and it is difficult to say that the curved surface adhesion to non-polar plastic is sufficient.

The present inventors have conducted further research following the previous invention, and as a result, the active energy ray-curable pressure-sensitive adhesive composition for hot melt of the present invention, further, for example, in one molecule such as diethylaminoethyl methacrylate One (meta)
Specific compounds having an acryloyl group and one tertiary amino group, and specific diene compounds such as 1,9-decadiene and / or one compound per molecule such as diethylene glycol methyl ether methacrylate. The melt viscosity at the time of coating can be reduced by incorporating a specific compound having two (meth) acryloyl groups and a (poly) oxyalkylene chain in a specific amount. The pressure-sensitive adhesiveness of the adhesive composition, adhesive strength, holding various excellent physical properties such as cohesion, or can be further improved, further,
The present inventors have found that the adhesive strength to a nonpolar plastic and the curved surface adhesiveness can be remarkably improved, and have completed the present invention.

[Means for solving the problem]

The present invention relates to the following A to E, A. 100 parts by weight of an acrylic (co) polymer having a weight average molecular weight by GPC of 50,000 to 500,000, 1 to 10 parts by weight of one or more compounds selected from the group of compounds having two or more acryloyl groups, methacryloyl groups, allyloxy groups and / or methallyloxy groups, and having a molecular weight of less than 1000, C. 0.5 to 25 parts by weight of a compound represented by the following general formula, D. A compound represented by the following general formula and / or 0.5 to 10 parts by weight of a compound represented by the following general formula, CH ₂ CRCR ⁵ -R ⁷ -CR ⁶ CHCH _{2. ^{CH 2 = CR 8 COO- (R}} 9 O) n -R 10 ...... It is another object of the present invention to provide an active energy ray-curable pressure-sensitive adhesive composition for hot melt, which comprises: E. 0.1 to 1 part by weight of an antioxidant.

 Hereinafter, the present invention will be described in detail.

The active energy ray-curable pressure-sensitive adhesive composition for a hot melt of the present invention is an acrylic (co) polymer, and its GPC polymerization average molecular weight is from 50,000 to 500,000. ) As a main component.

Examples of the acrylic (co) polymer (A) include the following (a) to (c), and (a) a general formula CH ₂ = CHCOOR ¹¹ (where R ¹¹ is a linear or branched C _{2 to} C ₁₈ ) (B) radical polymerization of an acrylate monomer represented by the formula (1), wherein the homopolymer has a glass transition point of −20 ° C. or lower: At least one other than the unsaturated group
(C) copolymerizable with the above (a) and (b),
The use of an acrylic (co) polymer obtained by (co) polymerizing a monomer other than (b) and (b) results in a balance between the adhesive force, cohesive force and pressure-sensitive adhesiveness of the resulting pressure-sensitive adhesive layer. It is preferable from the viewpoint of goodness.

The acrylate monomer of the above (a) is represented by the general formula CH
₂ = CHCOOR ¹¹ , the homopolymer has a glass transition point of -20 ° C or lower, and R ¹¹ of the acrylate monomer (a) is C _{2 to} C ₁₈ , preferably C ₂ to C _{12 represents} a linear or branched alkyl group. Examples of such groups R ^11, ethyl, n- propyl, n- butyl, i-
Examples thereof include a butyl group, an n-hexyl group, an n-octyl group, an i-octyl group, a 2-ethylhexyl group, and an i-nonyl group. Specific examples thereof include ethyl acrylate, n-propyl acrylate, and n-propyl. Examples thereof include butyl acrylate, i-butyl acrylate, n-hexyl acrylate, n-octyl acrylate, i-octyl acrylate, 2-ethylhexyl acrylate, and i-nonyl acrylate.

The amount of the acrylate monomer (a) used is, for example, 50% in the total 100% by weight of the monomers (a) to (c).
An amount of about 99.5% by weight, preferably about 63-96% by weight is suitable. By appropriately selecting and using the acrylate monomer (a) in the above-mentioned usage amount range, adhesive strength,
A good balance between pressure sensitive adhesion and cohesion can be achieved.

Examples of the monomer having at least one functional group in addition to the radically polymerizable unsaturated group (b) include a functional group such as a carboxyl group, an amide group or a substituted amide group, and an amino group. Alternatively, a monomer having a substituted amino group, a hydroxyl group, a mercapto group, or the like can be given. In the present invention, one or more monomers can be appropriately selected from these and used. . Specific examples of these monomers include, for example, acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, citraconic acid (preferably acrylic acid, methacrylic acid, itaconic acid) and the like. Carboxyl group-containing monomers; for example, acrylamide,
Methacrylamide, N, N-dimethylacrylamide, N
Amide group- or substituted amide group-containing monomers such as methylacrylamide (preferably acrylamide, methacrylamide); for example, aminoethyl acrylate, N, N-dimethylaminoethyl acrylate, N, N-diethylaminoethyl acrylate, N, Amino- or substituted amino-group-containing monomers such as N-dimethylaminoethyl methacrylate, N, N-diethylaminoethyl methacrylate, (preferably, N, N-dimethylaminoethyl methacrylate and N, N-diethylaminoethyl methacrylate); , 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, allyl alcohol, methallyl alcohol (preferably 2-hydroxyethyl acrylate, 2-, hydroxypropyl Acrylate, 2
-Hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate) and the like; and examples thereof include mercapto group-containing monomers such as vinyl mercaptan and allyl mercaptan. Among these monomers (b), it is preferable to use at least one or more monomers selected from the group consisting of a carboxyl group-containing monomer, an amide group-containing monomer and a substituted amino group-containing monomer. Particularly preferred.

The amount of the monomer (b) to be used depends on the amount of the monomer (a) to
For example, 0.5 to 15% by weight, preferably about 1 to 10% by weight of the total 100% by weight of (c) can be exemplified. When the amount of the monomer (b) is not more than the upper limit, the pressure-sensitive adhesive property of the obtained active energy ray-curable pressure-sensitive adhesive composition for hot melt does not become too low. It is preferable that the amount used is particularly 0.5% by weight or more, since a good balance between the adhesive force and the cohesive force can be achieved.

Further, as a monomer copolymerizable with the monomers (a) and (b), and a comonomer (c) other than the monomers (a) and (b), For example, methyl acrylate,
Acrylic ester monomers other than the above (a) such as t-butyl acrylate, cyclohexyl acrylate and stearyl acrylate; for example, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, n- Methacrylate monomers such as hexyl methacrylate, cyclohexyl methacrylate, n-octyl methacrylate, i-octyl methacrylate, 2-ethylhexyl methacrylate, i-nonyl methacrylate, n-dodecyl methacrylate, i-dodecyl methacrylate, and stearyl methacrylate; for example, formic acid Saturated fatty acid vinyl ester monomers such as vinyl, vinyl acetate, vinyl propionate and vinyl versatate; Over door, dibutyl fumarate,
Dibutyl itaconate, dioctyl malate, dioctyl fumarate, straight-chain or branched alkyl esters of C ₁ -C ₁₈ of alpha-beta-unsaturated dicarboxylic acids such as dioctyl itaconate; for example, styrene, alpha-methyl styrene,
Aromatic vinyl monomers such as vinyl toluene and ethyl vinyl benzene; vinyl cyanide monomers such as acrylonitrile and methacrylonitrile;

The amount of the comonomer (c) used is from the above-mentioned monomers (a) to
In general, the amount is preferably about 0 to 49.5% by weight, preferably about 3 to 36% by weight based on the total 100% by weight of (c). Since the use of the comonomer (c) can vary depending on the type of the comonomer, the amount of the comonomer cannot be uniquely determined. It is useful to adjust the balance and the like as desired, so that the above range can be appropriately selected so as to meet such purpose. When the amount of the comonomer (c) is equal to or less than the upper limit of the above range, the pressure-sensitive adhesiveness does not become too low, and an appropriate balance between the adhesive force and the pressure-sensitive adhesiveness is maintained. Therefore, when the comonomer (c) is used, it is preferable to select and use an appropriate amount within the above range.

The glass transition point (hereinafter sometimes abbreviated as Tg) of the acrylic (co) polymer which is the main component of the active energy ray-curable pressure-sensitive adhesive composition for hot melt of the present invention is preferably -20. ° C or lower, more preferably -30 ° C or lower. Temperatures below the upper limit are preferred because they have excellent pressure sensitive adhesive properties.

The weight average molecular weight of the acrylic (co) polymer according to the GPC method (hereinafter, may be abbreviated as w).
Is from 500,000 to 500,000, preferably from 100,000 to 400,000. Below the lower limit, the adhesive strength and cohesive strength of the obtained pressure-sensitive adhesive layer may be insufficient, while above the upper limit, a higher melting temperature may be required to obtain a suitable coating viscosity. Since it is necessary, thermal degradation of the acrylic (co) polymer and thermal polymerization of a compound having two or more acryloyl, methacryloyl, allyloxy and / or metallyloxy groups in one molecule described later, etc. This is not preferable because the above may occur.

In the present invention, the glass transition point (Tg) of the acrylic (co) polymer is a value measured and determined as follows.

Glass transition point: Approximately 10 mg of a sample of a 50% by weight organic solvent solution of an acrylic (co) polymer was weighed into a cylindrical cell made of aluminum foil having a thickness of about 0.05 mm and having an inner diameter of about 5 mm and a depth of about 5 mm. The sample is taken and dried at 100 ° C. for 2 hours to obtain a measurement sample. SSC-5000 differential scanning calorimeter manufactured by Seiko Electronic Industry Co., Ltd. (Differential
Using a Scanning Calormeter, the rate of temperature rise from -150 ° C to 10
Measure and determine in ° C / min.

The method for polymerizing the acrylic (co) polymer of the present invention is not particularly limited, and known methods such as solution polymerization and emulsion polymerization can be employed. In the production of the pressure-sensitive adhesive composition for an energy ray-curable hot melt, it is preferable to employ solution polymerization in which the treatment step is relatively simple and can be performed in a short time.

In the solution polymerization, generally, a predetermined organic solvent, a monomer, a polymerization initiator and a chain transfer agent used as needed are charged into a polymerization system, and a heating reaction is performed for several hours while stirring in a nitrogen stream or at the reflux temperature of the organic solvent. In this case, an organic solvent, a monomer, a polymerization initiator and / or a chain transfer agent may be sequentially added.

As the organic solvent, for example, benzene, toluene, xylene, aromatic hydrocarbons such as aromatic naphtha; n-
Aliphatic or alicyclic hydrocarbons such as hexane, n-heptane, n-octane, i-octane, n-decane, dipentene, petroleum spirit, petroleum naphtha, turpentine oil; ethyl acetate, n-butyl acetate; n-
Esters such as amyl acetate, 3-methoxybutyl acetate, methyl benzoate, cellobu acetate, butyl cellosolve acetate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, isophorone, cyclohexanone, methyl cyclohexanone;
Ethers such as methyl cellosolve, ethyl cellosolve, and butyl cellosolve; for example, methyl alcohol, ethyl alcohol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, i-butyl alcohol, s-butyl alcohol, t-butyl alcohol and the like; Alcohols; and the like. These organic solvents can be used alone or in combination of two or more.

Since the active energy ray-curable pressure-sensitive adhesive composition for hot melt of the present invention needs to be substantially solvent-free, the (co) polymer solution obtained from these organic solvents can be used. It is preferable to use an organic solvent having a boiling point of 50 to 150 ° C., particularly preferably 60 to 100 ° C., which is easy to volatilize the organic solvent and isolate the (co) polymer, especially n-hexane, ethyl acetate It is particularly preferable to use an organic solvent such as acetone, methyl ethyl ketone, methyl alcohol and n-propyl alcohol.

Examples of the polymerization initiator include benzoyl peroxide, lauroyl peroxide, caproyl peroxide, di-i-propylperoxydicarbonate, di-2-ethylhexylperoxydicarbonate, t-butylperoxyvivalate, and the like. Organic peroxides of, for example, 2,2'-azobis-i-butyronitrile,
2,2'-azobis-2,4-dimethylvaleronitrile, 2,
An azo compound such as 2'-azobis-4-methoxy-2,4-dimethylvaleronitrile; and the like can be used alone or in combination. The polymerization initiator is generally used in an amount of about 0.01 to 0.3 parts by weight, more preferably about 0.01 to 0.15 parts by weight, based on 100 parts by weight of the total amount of the monomers.

Further, as the chain transfer agent, for example, cyanoacetic acid; alkyl cyanoacetate esters alkyl group C ₁ -C _8; bromoacetic acid esters alkyl group C ₁ -C _8;; bromoacetate anthracene, phenanthrene, fluorene, 9
Aromatic compounds such as -phenylfluorene; aromatic nitro compounds such as p-nitroaniline, nitrobenzene, dinitrobenzene, p-nitrobenzoic acid, p-nitrophenol, p-nitrotoluene; benzoquinone, 2,3,5,
Benzoquinone derivatives such as 6-tetramethyl-p-benzoquinone; borane derivatives such as tributylborane; carbon tetrabromide, carbon tetrachloride, 1,1,2,2-tetrabromoethane, tribromoethylene, trichloroethylene, bromotrichloro methane, tribromo methane, 3-chloro-1-halogenated hydrocarbons such as propellers; chloral, aldehydes such as furaldehyde, alkyl mercaptans C ₁ -C _18; thiophenol, aromatic mercaptans such as toluene mercaptan Mercaptoacetic acid; C _{1 of} mercaptoacetic acid
-C ₁₀ alkyl esters; hydroxamate Le alkyl mercaptans of C ₁ -C _12; Binen, terpenes such Tapinoren; can be exemplified.

When the above-mentioned chain transfer agent is used, the amount thereof is preferably about 0.005 to 3.0 parts by weight per 100 parts by weight of the total of monomers.

The polymerization temperature is generally in the range of about 30 to 180 ° C, preferably about 60 to 150 ° C.

The (co) polymer solution suitably used in the present invention thus obtained usually contains the acrylic (co) polymer in an amount of from 20 to
In order to obtain the hot-melt pressure-sensitive adhesive composition of the present invention containing 90% by weight, an organic solvent is removed from the (co) polymer solution by a known method such as distillation to remove the acrylic ( The (co) polymer is isolated.

The active energy ray-curable pressure-sensitive adhesive composition for hot melt according to the present invention is the acrylic (co) polymer (A) described above.
In addition, a compound having two or more acryloyl groups, methacryloyl groups, allyloxy groups and / or methallyloxy groups in one molecule and having a molecular weight of less than 1000 (hereinafter sometimes abbreviated as a polyunsaturated compound) And one or more compounds (B) selected from the group of

When a polyunsaturated compound (B) having a molecular weight of 1,000 or more is used, the melt viscosity of the obtained hot-melt pressure-sensitive adhesive composition becomes high, so that a higher coating temperature is required to obtain a suitable coating viscosity. However, in this case, thermal degradation of the acrylic (co) polymer and thermal polymerization of the polyunsaturated compound or the like may occur, which is not preferable.

Such polyunsaturated compounds include, for example, ethylene glycol diglycidyl ether diacrylate,
Diethylene glycol diglycidyl ether dimethacrylate, triethylene glycol diglycidyl ether dimethacrylate, propylene glycol diglycidyl ether diacrylate, sorbitol tetraglycidyl ether tetramethacrylate, glycerol triglycidyl ether triacrylate, bisphenol A
Poly (meth) acrylates of polyepoxy compounds such as diglycidyl ether diacrylate; for example, ethylene glycol dimethacrylate, diethylene glycol diacrylate, tetraethylene glycol diacrylate, tripropylene glycol diacrylate, 1,4
-Butanediol diacrylate, neopentyl glycol dimethacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate hydroxybivalate, trimethylolethane trimethacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate Poly (meth) acrylates of polyols such as pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate; for example, (meth) allyl (meth) acrylates such as allyl acrylate and allyl methacrylate; for example, diallyl maleate (Meth) allyl ester of radically polymerizable dicarboxylic acid such as diaryl fumarate, diallyl itaconate, etc. For example, diallyl phthalate, triallyl cyanurate, polycarboxylic acids other than the above, such as triallyl isocyanurate (meth) allyl ester; and the like can be given.

Among these polyunsaturated compounds (B), the use of polyol poly (meth) acrylate is preferred from the viewpoint of easy availability and good balance of various physical properties of the obtained pressure-sensitive adhesive composition. Each of these alone,
Alternatively, two or more kinds of these polyunsaturated compounds can be used as a mixture, but two or more kinds of these polyunsaturated compounds are preferably used for reasons such as a good balance between pressure-sensitive adhesiveness, adhesion and cohesion.

The amount of the polyunsaturated compound (B) used is 1 to 10 parts by weight, preferably 2 to 8 parts by weight, based on 100 parts by weight of the acrylic (co) polymer (A). If the pressure-sensitive adhesive layer is used at the upper limit, the pressure-sensitive adhesive property of the obtained pressure-sensitive adhesive layer may be reduced. If the pressure-sensitive adhesive layer is less than the lower limit, the effect of adding the component (B) is less likely to be exhibited. Is insufficient, and the cohesive strength and adhesive strength of the pressure-sensitive adhesive layer may be insufficient, which is not preferable.

The active energy ray-curable pressure-sensitive adhesive composition for hot melt according to the present invention is the acrylic (co) polymer (A) described above.
And the polyunsaturated compound (B) together with the following general formula: (Hereinafter sometimes abbreviated as amino monomer). Where R ¹
Is H or CH ₃ , X is O or NH, R ² is a C ₁ -C ₆ linear or branched alkylene group, preferably a C ₂ -C ₄ linear alkylene group, and R ³ and R ⁴ are Each of the C ₁ -C ₄ linear or branched alkyl groups independently, preferably C ₁ -C _2, is an alkyl group.

Specific examples of such a compound (C) include, for example,
(Meth) acrylic acid esters of tertiary amino alcohols such as dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate and diethylaminoethyl methacrylate; for example, tertiary amino acids such as dimethylaminopropyl acrylamide and dimethylaminopropyl methacrylamide Alkyl-substituted (meth) acrylamide; and the like, and from the viewpoints of easy availability, low odor of the obtained composition, and good adhesion and curved surface adhesion, diethylaminoethyl methacrylate and dimethylaminopropyl The use of acrylamide is preferred.

The amount of the compound (C) used is the same as that of the acrylic (co)
The amount is 0.5 to 25 parts by weight, preferably 1 to 15 parts by weight, particularly preferably 1 to 10 parts by weight, based on 100 parts by weight of the polymer (A). If the amount is less than the lower limit, the effect of lowering the viscosity at the time of coating of the obtained adhesive composition is insufficient, which is not preferable. Adhesiveness and adhesive strength may decrease, which is not preferable.

The active energy ray-curable pressure-sensitive adhesive composition for a hot melt of the present invention is used together with the acrylic copolymer (A) and the polyunsaturated compound (B) together with a compound represented by the following general formula and / or It contains the compound (D) of the above general formula.

CH ₂ = CR ⁵ -R ⁷ -CR ⁶ = CH ₂ ... CH ₂ = CR ⁸ COO- (R ⁹⁰ ) _n -R ¹⁰ ... Here, R ⁵ , R ⁶ and R ⁸ are each independently H or CH ₃ , R
⁷ is a C _{4 to} C ₁₆ linear or branched alkylene group, R ⁹ is a C ₂ to
C _6, preferably a linear or branched alkylene group of C ₂ ~C _3, R ¹⁰ is a C ₁ -C _12, preferably C ₁ -C straight or branched ₁₀ alkyl group or C ₆ -C ₁₈ A phenyl group or an alkylphenyl group, n is 1 to 30, preferably 1 to
10, particularly preferably an integer of 1 to 5.

Specific examples of the compound of the above general formula (hereinafter sometimes abbreviated as diene monomer) include, for example, 1,9-decadiene, 1,13-tetradecadiene and the like.

Specific examples of the compound of the above general formula (hereinafter may be abbreviated as an oxyalkylene monomer) include, for example, ethylene glycol methyl ether acrylate, ethylene glycol n-butyl ether acrylate, ethylene glycol phenol ether acrylate, ethylene glycol Glycol nonyl phenol ether acrylate, diethylene glycol methyl ether methacrylate, diethylene glycol 2-ethylhexyl ether acrylate, triethylene glycol methyl ether acrylate, tetraethylene glycol methyl ether methacrylate, tetraethylene glycol phenol ether acrylate, tetraethylene glycol nonyl phenol ether acrylate, polyethylene glycol ( n = 9) methyl ether methacrylate, dipropylene glycol methyl ether acrylate, polypropylene glycol (n = about 2.5) can be mentioned nonylphenol ether acrylate.

The compound (D), that is, the compound represented by the general formula and / or the compound represented by the general formula is used in an amount of 0.5 to 10 parts by weight based on 100 parts by weight of the acrylic copolymer (A). , Preferably 1 to 5 parts by weight. If the amount is less than the lower limit, the effect of improving the adhesive strength of the obtained adhesive composition to a non-polar plastic is insufficient, which is not preferable. The curved surface adhesiveness and cohesive strength to polar plastic may decrease, which is not preferable.

Each of the components (B) to (D) acts as a diluent for the acrylic (co) polymer (A) before irradiation with active energy rays so as to maintain the viscosity at the time of coating at a moderately low level. It is preferable to use a material which is polymerized by irradiation with active energy rays and / or undergoes a cross-linking reaction with the acrylic (co) polymer (A) to form a solid resin. Therefore, as the components (B) to (D), those having a melting point of room temperature (about 20 ° C.) or lower and a boiling point of 160 ° C. or higher are preferable.

The active energy ray-curable pressure-sensitive adhesive composition for hot melt of the present invention comprises the acrylic (co) polymer (A), polyunsaturated compound (B), amino monomer (C), and diene. Containing 0.1 to 1 part by weight of an antioxidant (E) with respect to 100 parts by weight of the (co) polymer (A) together with the system monomer and / or oxyalkylene monomer (D) = It is. If the amount of the antioxidant (E) exceeds the upper limit, the curing reaction by irradiation with active energy rays is difficult to proceed sufficiently, and the cohesive strength and adhesive strength of the obtained pressure-sensitive adhesive layer may be insufficient. On the other hand, if it is less than the lower limit, the effect of adding the component (E) is less likely to appear, so that the acrylic (co) polymer is thermally degraded during heat coating, or the polyunsaturated compound or the like is thermally polymerized. In some cases, an excellent pressure-sensitive adhesive layer may not be obtained, and it may not be possible to reuse the heated pressure-sensitive adhesive composition for hot melt.

As the above antioxidant, generally, phenolic,
There are aromatic amines, sulfides, phosphites and the like. Of these, for example, 2,6-di-t-butyl-
4-methylphenol, n-octadecyl-3-
(3 ', 5'di-tert-butyl-4'-hydroxyphenyl) propionate, pentaerythritol-tetrakis [3- (3', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate], 2 Phenolic antioxidants such as 2,2'-methylenebis (6-t-butyl-4-methylphenol) monoacrylate are preferable because they have excellent heat stability, oxidation stability, heat discoloration resistance, and evaporation resistance. 2,2'-Methylenebis (6-t-butyl-4-methylphenol) monoacrylate is most preferred from the viewpoint of the less coloring of the pressure-sensitive adhesive layer from which the resulting pressure-sensitive adhesive layer is obtained.

The active-energy-ray-curable pressure-sensitive adhesive composition for hot melt of the present invention may be prepared by using the acrylic (co) polymer (A), polyunsaturation when the ultraviolet ray or the like is used as the active energy ray as described later. Use of a photopolymerization initiator in addition to compound (B), amino monomer (C), diene monomer and / or oxyalkyl monomer (D), and antioxidant (E) Can be.

Examples of the photopolymerization initiator include diacetyl, benzyl, benzophenone, benzoin, ω-bromoacetophenone, chloroacetone, benzoquinone, anthraquinone, 2-ethylanthraquinone, benzoin isopropyl ether, and benzoin ethyl ether. Can be 0.1 to 15 parts by weight based on 100 parts by weight in total of the above (A) to (D).

In addition, the pressure-sensitive adhesive composition of the present invention is selected from water and the organic solvent used in the solution polymerization of the acrylic (co) polymer as long as the excellent effects of the present invention are not impaired. A volatile solvent having a boiling point of 250 ° C. or less under normal conditions may be contained, but the content of these solvents depends on the acrylic (co) polymer (A), the polyunsaturated compound (B) and the amino monomer. It is at most 10 parts by weight, preferably at most 5 parts by weight, particularly preferably at most 1 part by weight, based on 100 parts by weight of the total of (C) and the diene monomer and / or oxyalkylene monomer (D). Is good.

The pressure-sensitive adhesive composition of the present invention further optionally,
For example, cumarone indene resin, terpene phenol resin, pt-butylphenol acetylene resin,
Phenol / formaldehyde resin, tempen resin, xylene / formaldehyde resin, petroleum hydrocarbon resin,
Tackifying resins such as hydrogenated hydrocarbon resins, rosin derivatives, and turpentine resins; for example, ethylene-vinyl acetate copolymer resins, ethylene-acrylic copolymer resins, ethylene-vinyl acetate-acrylic copolymer resins And other modifying resins; and the like. The addition amount of these resins is, based on 100 parts by weight of the total of the components (A) to (D), a tackifying resin, for example, 0 to 60 parts by weight, particularly 0 to 40 parts by weight; Resin, for example, 0-50
Parts by weight, especially 0 to 20 parts by weight;

In addition to these, the pressure-sensitive adhesive composition of the present invention may be optionally used, for example, a phthalic acid ester such as dioctyl phthalate, a phosphate ester such as tricresyl phosphate, a plasticizer such as polybutene or process oil. Organic or inorganic coloring agents such as titanium oxide, carbon black, phthalocyanine blue, etc .;
Known additives such as inorganic fillers such as talc, calcium carbonate, silica, aluminum hydroxide, and glass powder; photopolymerization initiation aids; ultraviolet absorbers;

As described above, the pressure-sensitive adhesive composition of the present invention is preferably added to an acrylic (co) polymer solution obtained by solution polymerization in an organic solvent having a boiling point of 60 to 100 ° C., such as ethyl acetate. Polyunsaturated compounds (B) such as methylolpron triacrylate and ethoxylated trimethylolpropane triacrylate; amino monomers (C) such as diethylaminoethyl methacrylate; and diene-based monomers such as 1,9-decadiene And / or an oxyalkylene-based monomer (D) such as, for example, diethylene glycol methyl ether methacrylate, for example, 2,2'-methylenebis (6-t-
An antioxidant (E) such as butyl-4-methylphenol) monoacrylate (trade name: Sumilizer GM, manufactured by Sumitomo Chemical Co., Ltd.) and, if necessary, a photopolymerization initiator such as benzoin ethyl ether. After sufficiently stirring and mixing, the organic solvent used during the solution polymerization is distilled off by heating, and the organic solvent is further removed using a means such as drying under reduced pressure.If necessary, a tackifying resin may be used. It can be produced by adding and mixing a modifying resin, a plasticizer, and a pigment.

The active energy ray-curable pressure-sensitive adhesive composition for hot melt of the present invention is generally melted by heat according to a known method, applied to various substrates at an appropriate thickness, and then formed. By irradiating active energy rays to such an extent that the pressure-sensitive adhesive property of the layer is not lost, the layer can be cured to form a pressure-sensitive adhesive layer on the base material. Examples of the melting temperature include a temperature of about 100 to 180 ° C.

The above active energy rays are ultraviolet rays or electron beams,
α-rays, β-rays, ionizing radiations such as γ-rays or X-rays, such as problems with equipment, ease of handling, and the use of a pressure-sensitive adhesive composition that has better storage stability. From the viewpoint, the use of an electron beam is preferred.

The term "to the extent that the pressure-sensitive adhesive property is not lost" means that the value of the pressure-sensitive adhesive property is 100 g / in accordance with the method of JIS Z-0237 as described later.
It means that it is 25mm or more.

For example, when the active energy ray is ultraviolet light, the irradiation dose of the active energy ray can be adjusted by adjusting the intensity of the lamp, the distance to the surface to be irradiated, and the irradiation time. 10 using a luminometer
10001000 mJ / cm ² , preferably 50 to 500 mJ / cm ² .

In the case of an electron beam, for example, the irradiation dose can be adjusted by adjusting the voltage, current, and irradiation time, and the dose is measured using a CTA dosimeter on the irradiation surface, and is 0.5 to 10 Mrad, preferably 2 to 8 Mrad. It is better to

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

The method of measuring the viscosity at the time of heating and the method of evaluating the thermal stability of the composition of the present invention, the method of preparing a pressure-sensitive adhesive sheet for the physical property test of the pressure-sensitive adhesive layer, and the pressure-sensitive adhesiveness, adhesive strength, cohesive strength and The measuring method of the curved surface adhesion is as follows.

(1) Measurement of viscosity during heating Using a Contrabass viscometer Rheomat 30 (trade name), cone plate PK1, measurement temperature 150 ° C, shear rate 50se
Measure under c- ¹ condition. The hot viscosity of the composition of the present invention is preferably 10,000 cps or less.

(2) Thermal stability of the composition The pressure-sensitive adhesive composition for an energy ray-curable hot melt is placed in a glass bottle, sealed, and left in a thermostat at 150 ° C to measure the time until the fluidity disappears. The thermal stability is preferably at least one day, particularly preferably at least three days.

(3) Method of preparing pressure-sensitive adhesive sheet for testing A pressure-sensitive adhesive composition for an electron beam-curable hot melt melted at 150 ° C. on a 50 μm polyethylene terephthalate film so as to have a thickness of about 25 μm. Coating, irradiating the surface of the obtained layer of the composition with an electron beam of 4 Mrad,
The composition was cured to obtain a test pressure-sensitive adhesive sheet.

(4) Measurement of pressure-sensitive adhesiveness Polished with water-resistant abrasive paper of # 280 specified in JIS R-6253
The test pressure-sensitive adhesive sheet prepared in (3) was pressed on a stainless steel plate of SUS304 in accordance with the method of JIS Z-0237.
After 0 minute, the peel strength (g / 25 mm) is measured under the conditions of 20 ° C., 65% RH, and a peel speed of 300 mm / min. The value of the pressure-sensitive adhesiveness is preferably 600 g / 25 mm or more, and 1000 g / 25 m
It is particularly preferred that it is at least m.

(5) Measurement of adhesive strength Polished with # 280 water-resistant abrasive paper specified in JIS R-6253
SUS304 stainless steel plate and polyethylene plate (JIS K
Γ ₀ = 43 dyn / cm) using the pressure-sensitive adhesive sheet for test prepared in (3) according to the method of JIS Z-0237 according to the method specified in −6768, and after 24 hours, 20 ° C., 65% RH, Peeling speed 30
The peel strength (g / 25 mm) is measured under the condition of 0 mm / min. The adhesive strength is preferably 1000 g / 25 mm or more, and particularly preferably 1400 g / 25 mm or more.

(6) Measurement of cohesive strength Polished with # 280 water-resistant abrasive paper specified in JIS R-6253
The test pressure-sensitive adhesive sheet prepared in (3) was adhered to a SUS304 stainless steel sheet so that the adhesion area was 25 × 25 mm ² , and the 2 kg roller was reciprocated once and pressed.

A 1 kg static load is applied to the sample in an atmosphere of 40 ° C. × 30% RH, and the time until the load drops is measured. The cohesive force is preferably at least 100 minutes, particularly preferably at least 500 minutes.

(7) Measurement of curved surface adhesiveness 10 mm × 20 from the test pressure-sensitive adhesive sheet created in (3)
mm specimen was cut out and affixed to a φ10 mm polyethylene rod [the same polyethylene used in (5)].
After standing for 24 hours at 65 ° C. and 65% RH, the state of the test piece floating from the rod is observed.

；: No lifting ；: slightly floating ×: completely floating It is necessary that the surface adhesion be ○.

Reference Example 1 In a separable flask equipped with a reflux condenser, a thermometer, a stirrer, and a sequential dropping device, an organic solvent for initial addition and 80 parts by weight of ethylacetate (EAc) as a polymerization initiator and azobisisobutyronitrile were used. (AIBN) 0.0125 parts by weight, and then add 25 parts by weight of a monomer mixture consisting of 94 parts by weight of butyl acrylate (BA) and 6 parts by weight of acrylic acid (AA), and heat the mixture. The polymerization was carried out for 40 minutes while adjusting the temperature.

Next, while maintaining the internal temperature at 80 to 85 ° C., a mixture for sequential addition consisting of 75 parts by weight of the remaining amount of the monomer mixture, 20 parts by weight of EAc and 0.125 parts by weight of AIBN was successively dropped over about 90 minutes, and further 90 parts by weight. While maintaining the internal temperature at 80 to 85 ° C. for one minute, an acrylic copolymer solution having a solid content of about 50% by weight was obtained. The w of this copolymer is 17
The Tg was -42 ° C.

Reference Examples 2 to 5 Using the same apparatus as in Reference Example 1 and using the monomer composition, the initial addition mixture and the sequential addition mixture shown in Table 1, polymerization was carried out in the same manner as in Reference Example 1 to obtain an acrylic resin. A copolymer solution was obtained. Table 1 shows w and Tg of this copolymer.

Example 1 To 100 parts by weight of the acrylic copolymer solution obtained in Reference Example 1, Sumilizer GM [trade name: 2,2'-methylenebis (6-t-manufactured by Sumitomo Chemical Co., Ltd.) was used as an antioxidant. Butyl-4-methylphenol) monoacrylate (MBPM
A)], add 0.25 parts by weight, mix and concentrate by vacuum drying to a solid content of 99% by weight, and then trimethylolpropane triacrylate (TMPTA) as a polyunsaturated compound.
0.5 parts by weight and 1.5 parts by weight of Photomer 4149-SN (trade name; manufactured by San Nopco Co., Ltd .: ethoxylated trimethylolpropane triacrylate (TMPTEA)), 2.5 parts by weight of diethylaminoethyl methacrylate (DE) as an amino monomer, and oxy Blemmer PM as an alkylene monomer
One part by weight of E-100 (trade name; manufactured by NOF Corporation: diethylene glycol methyl ether methacrylate) was mixed with 1 part by weight to obtain an electron beam-curable pressure-sensitive adhesive composition for hot melt. Table 2 shows the measurement results of various physical properties of the obtained composition.

Example 2 and Comparative Examples 1 and 2 An electron beam-curable pressure-sensitive adhesive composition for hot melt was obtained in the same manner as in Example 1, except that the amount of TMPTA and / or TMPTEA was changed. Table 2 shows the measurement results of the composition and various physical properties of the obtained composition.

Examples 3 to 5 and Comparative Example 3 A pressure-sensitive adhesive composition for an electron beam-curable hot melt was obtained in the same manner as in Example 1 except that the amount of DE was changed or not used. Table 2 shows the measurement results of the composition and various physical properties of the obtained composition.

Example 6 A pressure-sensitive adhesive composition for an electron beam-curable hot melt was prepared in the same manner as in Example 1 except that dimethylaminopropylacrylamide (DMAPAA) or 2-ethylhexyl acrylate (2EHA) was used instead of DE. Obtained. Table 2 shows the measurement results of the composition and various physical properties of the obtained composition.

Example 7 and Comparative Example 4 In Example 1, the pressure-sensitive adhesive composition for an electron beam-curable hot melt was prepared in the same manner as in Example 1 except that the amount of Blemmer PME-100 (trade name) was changed or not used. I got Table 2 shows the measurement results of the composition and various physical properties of the obtained composition.

Examples 8 to 10 In Example 1, instead of Blemmer PME-100 (trade name), ARONIC M-117 [trade name; manufactured by Toa Gosei Chemical Industry Co., Ltd .: diethylene glycol methyl ether acrylate], 1,9-decadiene (DDE) or 1,13-
An electron beam-curable pressure-sensitive adhesive composition for a hot melt was obtained in the same manner except that tetradecadiene (TDDE) was used. Table 2 shows the measurement results of the composition and various physical properties of the obtained composition.

Comparative Examples 5 and 6 In the same manner as in Example 1, except that the acrylic copolymer solution of Reference Example 2 or 3 was used instead of the acrylic copolymer dense liquid of Reference Example 1, for an electron beam-curable hot melt. A pressure-sensitive adhesive composition was obtained. Table 2 shows the measurement results of the composition and various physical properties of the obtained composition.

Comparative Example 7 A pressure-sensitive adhesive composition for an electron beam-curable hot melt was obtained in the same manner as in Example 1 except that no antioxidant was used. Table 2 shows the measurement results of the composition and various physical properties of the obtained composition.

Examples 11 and 12 The procedure of Example 1 was repeated, except that the acrylic copolymer solution of Reference Example 4 or 5 was used instead of the acrylic copolymer solution of Reference Example 1. A pressure-sensitive adhesive composition was obtained. Table 2 shows the measurement results of the composition and various physical properties of the obtained composition.

Examples 13 and 14 The procedure of Example 9 was repeated, except that the acrylic copolymer solution of Reference Example 4 or 5 was used instead of the acrylic copolymer solution of Reference Example 1. A pressure-sensitive adhesive composition was obtained. Table 2 shows the measurement results of the composition and various physical properties of the obtained composition.

Continuation of the front page (56) References JP-A-58-108276 (JP, A) JP-A-3-115481 (JP, A) JP-A-59-157164 (JP, A) JP-A-2-276879 (JP) JP-A-2-248482 (JP, A) JP-A-58-108275 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C09J 4/06 C09J 133/04- 133/16 C09J 171/00

Claims (1)

(57) [Claims] 1. The following AE, A. 100 parts by weight of an acrylic (co) polymer having a weight average molecular weight by GPC of 50,000 to 500,000, and B.1 molecule 1 to 10 parts by weight of one or more compounds selected from the group of compounds having two or more acryloyl groups, methacryloyl groups, allyloxy groups and / or methacryloxy groups and having a molecular weight of less than 1000 C. 0.5 to 25 parts by weight of a compound represented by the following general formula, D. A compound represented by the following general formula and / or 0.5 to 10 parts by weight of a compound represented by the following general formula, CH ₂ CRCR ⁵ -R ⁷ -CR ⁶ CHCH _{2. ^{CH 2 = CR 8 COO- (R}} 9 O) n -R 10 ...... And E. 0.1 to 1 part by weight of an antioxidant. A pressure-sensitive adhesive composition for an active energy ray-curable hot melt, which comprises: