JPH03115481A - Hot-melt pressure-sensitive adhesive composition curable by actinic radiation - Google Patents

Abstract

PURPOSE:To obtain the title composition excellent in pressure-sensitive adhesiveness, adhesive power, cohesive power, etc., and capable of improving the adhesion to a curved surface of a nonpolar plastics by mixing an acrylic (co)polymer with a specific polyunsaturated compound, a specific amine monomer, and an antioxidant. CONSTITUTION:100 pts.wt. acrylic (co)polymer having a weight-average molecular weight as determined by GPC of 50,000-500,000 is mixed with 1-10 pts.wt. compound having at least two (meth)acryloxy and/or (meth)allyloxy groups in the molecule and a molecular weight of below 1,000, 1-30 pts.wt. compound of the formula (wherein R<1> is H or CH3; X is O or NH; R<2> is 1-6C alkylene; R<3> and R<4> are each 1-4C alkyl), and 0.1-1 pt.wt. antioxidant (D) (e.g. 2,6-di-t- butyl-4-methylphenol) to give the title composition.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an active energy ray-curable hot melt pressure sensitive adhesive composition. A specific amount of one or more compounds selected from the group of compounds in a specific molecular weight range having two or more specific ethylenically unsaturated bonds in one molecule, one (meth)acryloyl group and one (meth)acryloyl group in one molecule. The present invention relates to an active energy ray-curable hot-melt pressure-sensitive adhesive composition containing a specified amount of a compound having tertiary amino groups and a specified amount of an antioxidant.

[Conventional technology and its problems]

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

For example, JP-A-50-1.36328 discloses r acrylic acid alkyl ester (alkyl group having 3 to 10 carbon atoms).
) 50 to 100 parts by weight, vinyl acetate 20 to 100 parts by weight, C0OH, CN, C0N in the side chain)! ! A copolymer mainly composed of 3 to 15 parts by weight of a vinyl monomer having a polar group selected from the group of A pressure-sensitive adhesive tape characterized by being irradiated with 3 to 35 Mrad of ionizing radiation to generate appropriate crosslinking is proposed.

However, in the above proposal, "pressure-sensitive adhesive tape"
Generally, irradiation with relatively high doses of ionizing radiation is required to impart sufficient cohesive strength to the pressure-sensitive adhesive layer, but in that case, the pressure-sensitive adhesive properties of the pressure-sensitive adhesive layer are extremely reduced. It is not easy to make the pressure-sensitive adhesive tape maintain various properties such as heat resistance, pressure-sensitive adhesiveness, adhesive force, and cohesive force in a well-balanced manner. Furthermore, if the irradiation dose of the ionizing radiation is too large, the "support sheet" may be deteriorated, and the material of the support sheet has its own limitations.

Furthermore, in order to use the proposed copolymer as a hot-melt pressure-sensitive adhesive, it must be heated to a fairly high temperature to ensure coating viscosity, which may cause thermal discoloration and thermal deterioration of the copolymer. Easy to cause problems.

Furthermore, if an organic solvent is used to avoid thermal coloring and thermal deterioration, the organic solvent will volatilize into the atmosphere during coating, deteriorating the working environment and easily causing problems such as air pollution.

Next, JP-A No. 59-176370 discloses that [100 parts by weight of a copolymer with a molecular weight of 100,000 to 600,000 containing an alkyl ester of acrylic acid or methacrylic acid as a main component,
Molecules with two or more unsaturated bonds in one molecule that can cause radical crosslinking by ultraviolet rays or electron beams 111,000
~20,000 oligomer 1-50 parts by weight and photosensitizer 0-10
A pressure-sensitive adhesive composition capable of radical crosslinking with ultraviolet rays or electron beams, which is prepared by blending parts by weight. It has been proposed for J.

However, the oligomer used in the second proposal above 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, so it is difficult to apply the proposed composition. The viscosity tends to be high during coating, and lowering the viscosity during coating requires heating at a higher temperature.
The oligomer is likely to undergo thermal polymerization, thermal deterioration, etc., resulting in coloring of the resulting pressure-sensitive adhesive layer, and maintaining the balance of various properties such as heat resistance, pressure-sensitive adhesion, adhesive strength, and cohesive force. This tends to be difficult. Another problem is that it is difficult to reuse the composition once it has been heated and melted.

The present inventors have carried out research to solve the problems of these conventional active energy ray-curable pressure-sensitive adhesives, and as a result, we have found that acrylic (co)polymers with a specific molecular weight have a
By containing a compound in a specific molecular weight range having two or more ethylenically unsaturated bonds in the molecule and a specific amount of antioxidant, the above-mentioned problems can be solved and an excellent pressure-sensitive active energy ray-curable hot melt can be obtained. He discovered that it was possible to obtain an adhesive composition and filed a patent application (Japanese Patent Application No.
No. 9965). Although the pressure-sensitive adhesive composition of the present invention is considerably superior to conventional ones, there are cases where a further increase in coating speed is required for the purpose of higher productivity, and such In some cases, further reduction in the viscosity of the composition is required. Furthermore, the hot-melt pressure-sensitive adhesive composition of Hikari's invention tends to have insufficient pressure-sensitive adhesive properties compared to solvent-based pressure-sensitive adhesives. For example, IO~20
There was also the problem that adhesion to curved surfaces to rod-like objects with a small diameter of about mmφ or molded products having etched parts was insufficient.

On the other hand, in order to reduce the viscosity of pressure-sensitive adhesives during coating, it has been known to use (meth)acrylic monomers such as n-butyl acrylate as diluents. , Japanese Patent Publication No. 58-108275
The publication states, ``General formula CHz = CHCOOR'
(where R' is an alkyl group having 2 to 14 carbon atoms) or a copolymer of the acrylic esters having different R1, and has a molecular weight of 5,000 to 300,000. Polymer 100 image 1, monomers 5-
An ionizing radiation-curable adhesive composition characterized in that the main components are 40 parts by weight and 10 to 10 parts by weight of an acrylic ester having two or more acryloyl groups in one molecule. ” is disclosed.

However, although the above proposed adhesive composition can reduce the viscosity during coating, the acrylic monomer used is generally highly volatile, has a strong odor, and is highly flammable. In addition to significantly deteriorating the working environment, there are many problems during storage, such as changes in the composition and viscosity of the adhesive composition over time due to the volatilization of the monomer, and the risk of fire. However, the adhesion to curved surfaces to non-polar plastics is also not sufficient.

As a result of further research following the previous invention, the present inventors have added to the active energy ray-curable hot melt pressure sensitive adhesive composition of the invention, for example, diethylaminoethyl methacrylate, etc. It is known that the melt viscosity during coating can be lowered by containing a specific amount of a specific compound having one (meth)acryloyl group and one tertiary amino group, and the previous invention also shows that melt viscosity during coating can be lowered. The pressure-sensitive adhesive composition retains various excellent physical properties such as pressure-sensitive adhesion, adhesion, and cohesive force, and can be used as an interlayer, and also has curved surface adhesion to non-polar plastics. The present invention has been completed based on the discovery that this can be significantly improved.

[Means for solving problems]

The present invention relates to the following A-D, A, acrylic (co)polymer 10, which has a weight average molecular weight of 50,000 to 500,000 by GPC.
0 parts by weight, B, one or two selected from the group of compounds having two or more acryloyl groups, methacryloyl groups, allyloxy groups and/or methacryloxy groups in one molecule, and whose molecular weight is less than 1000. 1 to 10 parts by weight of a compound of at least one species, 1 to 30 parts by weight of a compound represented by the following general formula [1], and 0.1 to 1 part by weight of D, an antioxidant. The object of the present invention is to provide an active energy ray-curable hot melt pressure-sensitive adhesive composition.

The present invention will be explained in detail below.

The active energy ray-curable hot melt pressure adhesive composition of the present invention is an acrylic (co)polymer, and its G
The main component is a (co)polymer (A) having a polymerization average molecular weight of 50,000 to 500,000 by PC.

The above acrylic (co)polymer (A) includes the following (a)
) ~ (C), (a) General formula CHz = CHC0OR' (However,
R5 represents a linear or branched alkyl group of 02 to C11);
For a monomer whose homopolymer has a glass transition point of 120"C or lower, if necessary, (b) a monomer having at least one functional group in addition to the radically polymerizable unsaturated group; and (C) a monomer other than (a) and (b) that can be copolymerized with the above (a) and (b), an acrylic (co)polymer obtained by (co)polymerizing It is preferable to use from the viewpoint of a good balance of adhesive strength, cohesive force, and pressure-sensitive adhesive properties of the resulting pressure-sensitive adhesive layer.

The acrylic ester monomer (a) above is generally represented by 2〇〇2=ClIC0OR5, the glass transition temperature of its homopolymer is 120°C or less, and the acrylic ester monomer ( R5 in a) represents a straight chain or branched alkyl group of 02 to CI11s, preferably C2 to CI2. Examples of such groups R5 include ethyl group, n
-Propyl group, n-butyl group, isobutyl group, n-hexyl group, n-octyl group, i-octyl group, 2-ethylhexyl group, i-nonyl group, etc. Specific examples include ethyl Acrylate, n-propyl acrylate, n-butyl acrylate, j-butyl acrylate, n-hexyl acrylate, n-octyl acrylate-1, i-octyl acrylate, 2-ethylhexyl acrylate, i-nonyl acrylate, etc. I can give an example.

The amount of the acrylic acid ester monomer (a) used is, for example, 5% of the total 100% of the monomers (a) to (C).
0-99.8% by weight, preferably 63-96.5% by weight
An amount of about 100% is suitable. The acrylic acid ester monomer (
By appropriately selecting and utilizing a) within the above usage amount range, a good balance of adhesive strength, pressure-sensitive adhesiveness and cohesive strength can be achieved.

Further, as for the monomer having at least one functional group in addition to the radically polymerizable unsaturated group (b), examples of the functional group include a carboxyl group, an amide group or a substituted amide group, and an amino group. Alternatively, monomers having a substituted amino group, hydroxyl group, or mercapto group can be mentioned, and in the present invention, one or more monomers can be appropriately selected and used from these. . Specific examples of these monomers include acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, citraconic acid (preferably acrylic acid, methacrylic acid, itaconic acid), etc. Carboxyl group-containing monomers; for example, amide group- or substituted amide group-containing monomers such as acrylamide, methacrylamide, N, N-dimethylacrylamide, N-methylacrylamide (preferably acrylamide, methacrylamide); Aminoethyl acrylate, N,N-dimethylaminoethyl acrylate, N.

N-diethylaminoethyl acrylate, N, N-
dimethylaminoethyl methacrylate, N, N-diethylaminoethyl methacrylate, (preferably N
, N-dimethylaminoethyl methacrylate, N,N-
Monomers containing amino groups or substituted amino groups such as diethylaminoethyl methacrylate); for example, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, allyl alcohol, methallyl alcohol (preferably 2-
Hydroxyl group-containing monomers such as hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate; for example, mercapto group-containing monomers such as vinyl mercaptan and allyl mercaptan; be able to. Among these monomers (b), it is preferable to use at least one monomer selected from the group of carboxy group-containing monomers, amide group-containing monomers, and substituted amino group-containing monomers. Particularly preferred.

The usage amount of the above monomers (a) to (C) is as follows:
For example, the amount may be about 0.5 to 15% by weight, preferably about 1 to 10% by weight out of the total 100% by weight.

If the amount of monomer (b) used is below the upper limit, the pressure-sensitive adhesive properties of the resulting active energy ray-curable hot-melt pressure-sensitive adhesive composition will not become too low; Preferably, the amount is in particular 0.5% by weight or more, so that a good balance of adhesive and cohesive strength can be achieved.

Furthermore, as a comonomer (C) which is copolymerizable with the monomers (a) and (b) above, and other than the monomers (a) and (b), For example, methyl acrylate,
Acrylic acid ester monomers other than the above (a) such as t-butyl acrylate, cyclohexyl acrylate, stearyl acrylate; for example, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate,
i-Butyl methacrylate, t-butyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, n-octyl methacrylate, i-octyl methacrylate, 2-ethylhexyl methacrylate-1'
, 1-nonyl methacrylate, n-dodecyl methacrylate, i-dodecyl methacrylate, stearyl methacrylate and other methacrylic acid ester monomers: for example,
Saturated fatty acid vinyl ester monomers such as vinyl formate, vinyl acetate, vinyl propionate, vinyl versatate;
For example, C1-CI8 linear or branched alkyl esters of α,β-unsaturated dicarboxylic acids such as dibutyl maleate, dibutyl fumarate, dibutyl itaconate, dioctyl maleate, dioctyl fumarate, dioctyl itaconate; Styrene, α-methylstyrene,
Examples include aromatic vinyl monomers such as vinyltoluene and ethylvinylbenzene; for example, vinyl cyanide monomers such as acrylonitrile and methacryloyl groups; and the like.

The amount of the comonomer (C) used is the amount of the comonomer (a) to (
Generally 0 to 49.8% by weight out of the total 100% by weight of C)
, preferably about 3 to 3645% by weight. The usage amount of the comonomer (C) can vary depending on the type of the comonomer, so the usage amount cannot be determined unambiguously;
It is useful for adjusting the balance between adhesive force and pressure-sensitive adhesiveness, and the balance between these and cohesive force as desired.
The amount can be appropriately selected within the above range to meet such objectives. If the amount of the comonomer (C) used is below the upper limit of the above-mentioned range, the pressure-sensitive adhesiveness will not become too low, and an appropriate balance between adhesive strength and pressure-sensitive adhesiveness will be maintained. Therefore, when using the comonomer (C), it is preferable to appropriately select and use the amount within the above range.

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

The weight average molecular weight (hereinafter sometimes abbreviated as Mw) of the acrylic (co)polymer according to the GPC method is from 50,000 to 500,000, preferably from 100,000 to 400,000. Below this lower limit, the resulting pressure-sensitive adhesive layer may lack adhesive strength and cohesive force, while above this upper limit, a higher melting temperature may be required to obtain a suitable coating viscosity. Because of this, thermal deterioration of the acrylic (co)polymer and [described later]
This is not preferable because thermal polymerization of compounds having two or more acryloyl groups, methacryloyl groups, allyloxy groups and/or metalryloxy groups in one molecule 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: Made of aluminum foil with a thickness of about 0.05 mm, inner diameter of about 51
1III+, about 10 samples of an organic solvent solution of about 50% by weight of acrylic (co)polymer were placed in a cylindrical cell with a depth of about 5 cm.
The sample was weighed, dried at 100°C for 2 hours, and used as the measurement sample. Seiko Electronic Industries ■'45SC5000 Differential Scanning Calorimeter (Differential Scanni)
ngCa 1 ormeter) at -150°C
Measurement is determined at a heating rate of 10°C/mjn.

The method of 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 adopted. In producing an energy beam-curable hot melt pressure-sensitive adhesive composition, it is preferable to employ solution polymerization, which is a relatively simple process and can be carried out in a short time.

In solution polymerization, a predetermined organic solvent, a monomer mixture, a polymerization initiator, and an optional chain transfer agent are generally placed in a polymerization system, and the polymerization is carried out for several hours while stirring in a nitrogen stream or at the reflux temperature of an aqueous solvent. The reaction is carried out by heating, and in this case, an organic solvent, a monomer, a polymerization initiator and/or a chain transfer agent may be added sequentially.

Examples of the above organic solvent include aromatic hydrocarbons such as benzene, toluene, xylene, and aromatic naphtha; n-
Aliphatic or alicyclic hydrocarbons such as hexane, n-hebutane, n-octane, i-octane, n-decane, dipentene, petroleum spirit, petroleum naphtha, turpentine; ethyl acetate, n-butyl acetate , n-amyl acetate, 3-methoxybutyl acetate, methyl benzoate, cellosolve acetate, butyl cellosolve acetate and other esters; acetone, methyl ethyl ketone, methyl isobutyl ketone, isophorone, cyclohexanone, methyl cyclohexanone and other ketones;
Ethers such as methyl cellosolve, ethyl cellosolve, butyl cellosolve; for example, methyl alcohol, ethyl alcohol, n-7' alcohol, i-propyl alcohol, n-butyl alcohol, i-7' alcohol, S-butyl alcohol, t -Alcohols such as butyl alcohol; etc. can be mentioned.

These organic solvents can be used alone or in a mixture of two or more.

The active energy ray-curable hot-melt pressure-sensitive adhesive composition of the present invention must be substantially solvent-free. It is preferable to use an organic solvent with a boiling point of 50 to 150°C, particularly 60 to 100°C, which is easy to volatilize and isolate the copolymer, and among them, n-hexane,
It is particularly preferred to use organic solvents such as ethyl acetate, acetone, methyl ethyl ketone, methyl alcohol, n-propyl alcohol.

Examples of the polymerization initiator include benzoyl peroxide, lauroyl peroxide, cabroyl peroxide, Jimmy propyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate,
Organic peroxides such as t-butyl peroxyvivalate; for example, 2,2'-azobis-i-butyronitrile; 2.
2'-azobis-2,4-dimethylvaleronitrile, 2
．． Azo compounds such as 2'azobis-4-methoxy-2,4-dimethylvaleronitrile; etc. can be used alone or in combination. The amount of the polymerization initiator used is generally about 0.0 parts by weight per 100 parts by weight of the monomer mixture.
1 to 0.3 parts by weight, more preferably about 0.01 to 0.1
It is preferable to use 5 parts by weight.

Further, as the chain transfer agent, for example, cyanoacetic acid;
Cyanoacetic acid alkyl esters of alkyl groups 01 to CII; bromoacetic acid; bromoacetic acid esters of alkyl groups C1 to C11: aromatic compounds such as anthracene, phenanthrene, fluorene, 9-phenylfluorene; p
- Aromatic nitro compounds such as nitroaniline, nitrobenzene, dinitrobenzene, p-nitrobenzoic acid, p-nitrophenol, p-nitrotoluene; benzoquinone, 2.3,5.6-tetramethyl-p-benzoquinone, etc. benzoquinone derivatives; borane derivatives such as tributylborane; carbon tetrabromide, carbon tetrachloride, 1,1,2.2 tetrabromoethane, tribromoethylene, trichloroethylene, fluorotrichloromethane, tribromomethane, 3
-halogenated hydrocarbons such as chloro-1-propene; aldehydes such as chloral and furaldehyde; CI""
' Alkyl mercaptans of C1B; Aromatic mercaptan necks such as thiophenol and toluene mercaptan; Mercaptoacetic acid; Cl-01° alkyl esters of mercaptoacetic acid; Hydrokylalkyl mercaptans of C1 to CI2; Terpenes such as pinene and terbilsin etc.

When the chain transfer agent is used, it is preferably used in an amount of about 0.05 to 3.0 parts by weight per 100 parts by weight of the monomer mixture.

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

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

The active energy ray-curable hot-melt pressure-sensitive adhesive composition of the present invention has an acryloyl group, a methacryloyl group, an allyloxy group, and/or a metalryloxy group in one molecule together with the above-mentioned acrylic (co)polymer (A). Contains one or more compounds (B) selected from the group of compounds having two or more of the following and whose molecular weight is less than 1000 (hereinafter sometimes abbreviated as polyunsaturated compounds) This is what happens.

If a polyunsaturated compound (B) with a molecular weight of 1,000 or more is used, the melt viscosity at the same temperature will increase, so a higher melting temperature will be required to obtain a suitable coating viscosity, but in that case, the acrylic This is not preferable since thermal deterioration of the system (co)polymer and thermal polymerization of the polyunsaturated compound may occur.

Examples of such polyunsaturated compounds include ethylene glycol diglycidyl ether diacrylate, diethylene glycol diglycidyl ether dimethacrylate, triethylene glycol diglycidyl ether dimethacrylate, propylene glycol diglycidyl ether diacrylate, and sorbitol tetraglycidyl ether tetramethacrylate. Poly(meth)acrylates of polyepoxy compounds such as , glycerol triglycidyl ether triacrylate, bisphenol A diglycidyl ether diacrylate; for example, ethylene glycol dimethacrylate, diethylene glycol diacrylate, tetraethylene glycol diacrylate, tripropylene glycol diacrylate , ■,
4-butanediol diacrylate, neopentyl glycol dimethacrylate, 1,6-hexanediol diacrylate, hydroxypivalate neopentyl glycol diacrylate, trimethylolethane trimethacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate , poly(meth)acrylates of polyols such as pentaerythritol triacrylate, pentaerythritol tetraacrylate, and dipentaerythritol hexaacrylate; (meth)allyl (meth)acrylates such as allyl acrylate and allyl methacrylate; (meth)allyl esters of radically polymerizable dicarboxylic acids such as ester, diallyl fumarate, and diallylitaconate; (meth)allyl of polycarboxylic acids other than the above, such as diallyl phthalate, triallyl cyanurate, and triallyl isocyanurate; Ester; etc. can be mentioned.

Among these polyunsaturated compounds (B), ease of acquisition,
From the viewpoint of a good balance of various physical properties of the resulting pressure-sensitive adhesive composition, it is preferable to use poly(meth)acrylate as a polyol. In addition, each of these polyunsaturated compounds can be used alone or in a mixture of two or more types, but for reasons such as a good balance of pressure-sensitive adhesiveness, adhesive force, and cohesive force, two or more types of these polyunsaturated compounds may be used in combination. It is preferable to use

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 it is used in excess of the upper limit, the pressure-sensitive adhesive properties of the resulting pressure-sensitive adhesive layer may be reduced, and if it is less than the lower limit, the effect of the addition of component (B) will not be apparent, and the viscosity at the time of coating may decrease. The effect of reducing the pressure-sensitive adhesive layer is insufficient, and the cohesive force and adhesive force of the pressure-sensitive adhesive layer may be insufficient, which is not preferable.

The active energy ray-curable hot-melt pressure-sensitive adhesive composition of the present invention comprises a compound represented by the following general formula (1), together with the acrylic (co)polymer (A) and polyunsaturated compound (B). (C) (hereinafter sometimes abbreviated as amino monomer). Here R
' is H or CH, 1, X is 0 or NH, R
2 is a C, -C6 straight chain or branched alkylene group, preferably a C2 to C4 straight chain alkylene group, and R3 and R4 are each independently a 01 to C4 straight chain or branched alkyl group, preferably C.

~C2 alkyl group.

Specific examples of such compounds (C) include (meth)acrylic acid esters of tertiary amino alcohols such as dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, and diethylaminoethyl methacrylate;
Tertiary aminoalkyl-substituted (meth)acrylamides such as dimethylaminopropyl acrylamide and dimethylaminopropylmethacrylamide;
Diethylaminoethyl methacrylate and dimethylaminopropylacrylamide are preferably used from the viewpoint of easy availability, low odor of the resulting composition, and good adhesive strength and curved surface adhesion.

The amount of the compound (C) used is 1 to 30 parts by weight, preferably 2 to 20 parts by weight, particularly preferably 3 to 15 parts by weight, based on 100 parts by weight of the acrylic copolymer (A). . If the amount used is too small (less than the lower limit), the effect of reducing the viscosity during coating of the resulting adhesive composition will be insufficient, and if the amount is too large, exceeding the upper limit, the pressure-sensitive This is not preferable because adhesive properties and adhesion strength may decrease.

Both of the above CB) and (C) components are acrylic (co)polymers (before active energy ray irradiation).
It acts as a diluent for A) to keep the viscosity at a moderately low level during coating, and polymerizes by itself when irradiated with active energy rays and/or undergoes a crosslinking reaction with the acrylic (co)polymer (A). It is preferable to use a material that can be turned into a solid resin. Therefore, it is preferable to use components (B) and (C) that have a melting point below room temperature (approximately 20'C) and a boiling point above 160''C, preferably above 200°C.

The active energy ray-curable hot-melt pressure-sensitive adhesive composition of the present invention includes the above-mentioned acrylic (co)polymer (A), polyunsaturated compound (B), and amino monomer (C).
The antioxidant (D) is contained in an amount of 0.1 to 1 part by weight based on 100 parts by weight of the (co)polymer (A). If the amount of antioxidant (D) used exceeds the upper limit, the curing reaction due to active energy ray irradiation will not proceed sufficiently;
The cohesive force and adhesive force of the resulting pressure-sensitive adhesive layer may be insufficient, which is not preferable; on the other hand, if it is less than the lower limit, the (D)
The effect of the addition of components is difficult to appear, and the acrylic (co)polymer deteriorates due to heat during hot coating, and the polyunsaturated compound etc. undergo thermal polymerization, making it impossible to obtain an excellent pressure-sensitive adhesive layer. This is not preferable because it may not be possible to reuse the heated hot-melt pressure-sensitive adhesive composition.

The above-mentioned antioxidants generally include phenol type, aromatic amine type, sulfide type, phosphite type, etc. Among these, for example, 2,6-di-L-butyl-
4-Methylphenol, n-octadecyl-3-(3'
, 5'-di-t-butyl-4'-hydroxyphenyl)propionate, pentaerythritol-tetrakis (3-(3',5-di-t-7'thyl-41-hydroxyphenyl)propionate), 2. Phenolic antioxidants such as 2'-methylenebis(6-t-butyl-4-methylphenol) monoacrylate are preferred because they have excellent thermal stability, oxidation stability, heat discoloration resistance, evaporation resistance, etc. ,2'-methylenebis(6-t-butyl-
4-methylphenol) monoacrylate is most preferred from the viewpoint of less coloring of the pressure-sensitive adhesive layer.

In the active energy ray-curable hot melt pressure-sensitive adhesive composition of the present invention, when ultraviolet light or the like is used as the active energy ray, the acrylic (co)polymer (A), the polyunsaturated compound, etc. (B), amino monomer (C)
In addition to the antioxidant (D), a photopolymerization initiator can be used in combination.

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

In addition, the pressure-sensitive adhesive composition of the present invention can be applied to water and the organic solvent used in the solution polymerization of the acrylic (co)polymer, within a range that does not impair the excellent effects of the present invention. It may contain a volatile solvent with a boiling point of 250°C or less under normal conditions, but the content of these solvents is limited to the amount of the acrylic (co)polymer (A), the polyunsaturated compound (B), and the amino monomer. The amount is preferably 10 parts by weight or less, preferably 5 parts by weight or less, particularly preferably 1 part by weight or less, based on a total of 100 parts by weight of body (C).

The pressure-sensitive adhesive composition of the present invention may further contain, if necessary, for example, coumaron-indene resin, thembene-phenol resin, pt-butylphenol-acetylene resin, phenol-formaldehyde resin, terpene resin, xylene, formaldehyde resin. , petroleum hydrocarbon resins, hydrogenated hydrocarbon resins, rosin derivatives, turpentine resins, and other tackifying resins; for example, ethylene-vinyl acetate copolymer resins, ethylene-acrylic copolymer resins, ethylene-acetic acid Other modifying resins such as vinyl-acrylic copolymer resins can be added. The amount of these resins to be added is, for example, 0 to 60 parts by weight of the tackifier resin, based on a total of 100 parts by weight of the components (A) to (C).
In particular, 0 to 40 parts by weight; other modifying resins, such as 0
It is preferably about 50 parts by weight, particularly 0 to 20 parts by weight.

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

As mentioned above, the pressure-sensitive adhesive composition of the present invention preferably includes, for example, ethyl acetate having a boiling point of 60 to 1. OOo
A polyunsaturated compound (B) such as trimethylolpropane triacrylate or ethoxylated trimethylolpropane triacrylate, such as diethylaminoethyl, is added to the acrylic (co)polymer solution obtained by solution polymerization in an organic solvent of C. Amino monomer (C) such as methacrylate, for example 2,2'-methylenebis(6-butyl-4-methylphenol) monoacrylate [
Product name: Sumilizer GM, manufactured by Sumitomo Chemical Co., Ltd.] and other antioxidants (D) and, if necessary, a photopolymerization initiator such as benzoin ethyl ether, are added and thoroughly stirred and mixed, and then added during solution polymerization. The organic solvent used is distilled off by heating, and further the organic solvent is removed using a method such as vacuum drying, and if necessary, a tackifying resin, a modifying resin, a plasticizer, and a pigment are added and mixed. It can be manufactured by

The active energy ray-curable hot-melt pressure-sensitive adhesive composition of the present invention is thermally melted according to a generally known method, coated on various substrates to an appropriate thickness, and then A pressure-sensitive adhesive layer can be formed on the substrate by curing by irradiating with active energy rays to an extent that the pressure-sensitive adhesive properties of the layer are not lost. The melting temperature is
For example, a temperature of about 100 to 180°C can be exemplified.

The active energy rays mentioned above include ultraviolet rays, electron beams, α
refers to ionizing radiation such as rays, β-rays, T-rays, or X-rays, from the viewpoints of equipment problems, ease of handling, and the possibility of using pressure-sensitive adhesive compositions with better storage stability. It is more preferable to use an electron beam.

The above-mentioned "to the extent that pressure-sensitive adhesiveness is not lost" means that the pressure-sensitive adhesiveness value is 100 g/25 mm or more according to the method of JIS Z-0237, as described later.

For example, when the active energy ray is an ultraviolet ray, the irradiation dose can be adjusted by adjusting the intensity of the lamp, the distance to the irradiated surface, and the irradiation time. 10 measured using a luminometer
~10100O/cd, preferably 50-500mJ
/cJ is better.

For example, in the case of electron beams, the irradiation dose can be adjusted by adjusting the voltage, current, and irradiation time, and the cough dose is 0.5 to 10
Mrad is preferably 2 to 8 Mrad.

(Examples) Hereinafter, the present invention will be explained in more detail by giving examples, reference examples, and comparative examples.

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

(1) Measurement of viscosity when heated Using a viscometer Reomatsu 1-30 (trade name) manufactured by Contrapass Co., Ltd., measurement is carried out under the conditions of a cone plate PKI, a measurement temperature of 150° C., and a sliding speed of 50 sec-'. The viscosity at heat of the composition of the present invention is preferably 10,000 cps or less.

(2) Composition Thermal Stability An energy beam-curable hot-melt pressure-sensitive adhesive composition is placed in a glass bottle, sealed, and left in a constant temperature bath at 150°C to measure the time until fluidity disappears. Thermal stability is preferably one day or more, particularly preferably three days or more.

(3) Method for making a pressure-sensitive adhesive sheet for testing An electron beam-curable hot melt pressure-sensitive adhesive composition melted at 150°C was placed on a 50μ polyethylene terephthalate film to a thickness of about 25μ. The surface of the resulting layer of the composition was irradiated with an electron beam of 4 Mrad and cured to obtain a pressure-sensitive adhesive sheet for testing.

(4) Measurement of pressure-sensitive adhesive property JIS Z-023 using the test pressure-sensitive adhesive sheet prepared in (3) on an SO3304 stainless steel plate polished with #280 water-resistant abrasive paper specified in JIS R-6253.
Crimp according to method 7, and after 20 minutes, 20゛C165%
The peel strength (g/25 mm) is measured under the condition of RH1 peel rate of 300 mm/min. The pressure-sensitive adhesive value is preferably 600 g/25 mm+, particularly preferably 1000 g/25 mm+.

(5) Measurement of adhesive strength JIS Z-023 using the test pressure-sensitive adhesive sheet prepared in (3) on an SO5304 stainless steel plate polished with #280 water-resistant abrasive paper specified in JIS R-6253.
Crimp according to method 7, and after 24 hours, 20°C 165
%R, H1 The peel strength (g/25 mm) is measured under conditions of a peel rate of 300 mm/mtn. The adhesive strength is preferably at least 1000 g/25 ntm, particularly preferably at least 1400 g/25 mm.

(6) Measurement of cohesive force A stainless steel plate of S [IS 304] polished with #280 water-resistant abrasive paper specified in JIS R-6253 was
) The adhesive area of the test pressure-sensitive adhesive sheet made with
The tape was pasted to a thickness of 25 mm, and a 2 kg roller was used to press it back and forth once.

A static load of 1 kg was applied to the sample in an atmosphere of 40°C x 30% RH, and the time until the load dropped was measured.

The cohesive force is preferably 100 minutes or more, and 5
It is particularly preferable that the duration is 0.00 minutes or more.

(7) Measurement of curved surface adhesion 1010 m from the test pressure-sensitive adhesive sheet created in (3)
A test piece of m×20 was cut out, and a φ10 mm polyethylene rod [γ according to the method specified in JIS K-6768.

= 43 dyn/cm polyethylene], 2
After being left for 24 hours at 0°C and 165% RH, observe how the test piece lifts from the rod.

O: No floating △; Slightly lifted ×; Completely floating Curved surface adhesion must be ○.

Reference Example 1 In a separable flask equipped with a reflux condenser, a thermometer, a stirrer, and a sequential dropping device, 30 parts of ethyl acetate-1-(EAc) and azobisisobutylene were added as an organic solvent for initial addition and a polymerization initiator. Ronitrile (ArBN) 0.
01.25 parts by weight and then butyl acrylate (
25 parts by weight of a monomer mixture consisting of 94 parts by weight of BA) and 6 parts by weight of acrylic acid (A, A) was added and heated, and polymerization was carried out for 40 minutes while adjusting the internal temperature to 80 to 85 °C. .

Next, while maintaining the internal temperature at 80 to 85°C, the remaining 75 parts by weight of the monomer mixture, 20 parts by weight of EAc, and AIB No.
A mixture for sequential addition consisting of 125 parts by weight was sequentially added dropwise over about 90 minutes, and the internal temperature was maintained at 80 to 85° for another 90 minutes.
C. to obtain an acrylic copolymer solution with a solid content of about 50% by weight. The Mw of this copolymer is 170,000, and the Tg is -42.
It was °C.

Reference Examples 2 to 5 Polymerization was carried out in the same manner as in Reference Example 1 using the same equipment as in Reference Example 1 and the monomer mixture composition shown in Table 1, the mixture for initial addition, and the mixture for sequential addition. A copolymer solution was obtained. The Mw and Tg of this copolymer are shown in Table 1.

Example 1 100 parts by weight of the acrylic copolymer solution obtained in Reference Example 1 was added with Sumilizer 〇M [trade name: manufactured by Sumitomo Chemical Co., Ltd.: 2,2'-methylenebis(6-mo-butyl)] as an antioxidant. -4-methylphenol) monoacrylate (
MBPMA)) Add 0.25 parts by weight, mix, and dry under reduced pressure until the solid content reaches 99% by weight. ! 4 condensation, and then 0.5 parts by weight of trimethylolpropane triacrylate (TMPTA) as a polyunsaturated compound and Photomer 4149-3N (trade name; manufactured by San Nobuco: ethoxylated trimethylolpropane triacrylate (TMPT)
An electron beam curable hot melt pressure-sensitive adhesive composition was obtained by mixing 1.5 parts by weight of EA) and 2.5 parts by weight of diethylaminoethyl methacrylate-1-(DE) as an amino monomer.

Table 2 shows the measurement results of various physical properties of the obtained composition.

Example 2 and Comparative Example 1.2 In Example 1, TMPTA and/or TMPT
An electron beam curable hot melt pressure sensitive adhesive composition was obtained in the same manner except that the amount of EA used was changed. Table 2 shows the composition and measurement results of various physical properties of the obtained composition.

Example 3 and Comparative Example 3 Electron beam-curable hot melt pressure-sensitive adhesive compositions were obtained in the same manner as in Example 1, except that the amount of DB used was changed or DB was not used. Table 2 shows the composition and measurement results of various physical properties of the obtained composition.

Example 4 and Comparative Example 4 Electron beam curable hot melt pressure sensitive was produced in the same manner as in Example 1 except that dimethylaminopropylacrylamide (DMAPAA) or 2-ethylhexyl acrylate (2EHA) was used instead of DE. An adhesive composition was obtained. Table 2 shows the composition and measurement results of various physical properties of the obtained composition.

Comparative Examples 5 and 6 Electron beam hard quince hot melt texture was prepared 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 solution of Reference Example 1. A pressure adhesive composition was obtained. Table 2 shows the composition and measurement results of various physical properties of the obtained composition.

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

Examples 5 and 6 Electron beam curable hot melt pressure sensitive was produced in the same manner as in Example 1, except that the acrylic copolymer solution of Reference Example 4 or 5 was used instead of the acrylic copolymer solution of Reference Example 1. An adhesive composition was obtained. Table 2 shows the composition and measurement results of various physical properties of the obtained composition.

hand Continued inertia Positive book December 15, 1999

Claims (1)

[Claims] (1) The following A to D, A, 100 parts by weight of an acrylic (co)polymer whose weight average molecular weight according to GPC is 50,000 to 500,000, B, acryloyl group in one molecule, 1 to 10 parts by weight of one or more compounds selected from the group of compounds having two or more methacryloyl groups, allyloxy groups and/or metalryloxy groups and whose molecular weight is less than 1000, C, the following: 1 to 30 parts by weight of a compound represented by the general formula [1], ▲Mathematical formulas, chemical formulas, tables, etc.▼... [1] [However, R^1 is H or CH_3, X is O or NH
, R^2 is a linear or branched alkylene group of C_1 to C_6, R^3 and R^4 are each independently C_1 to C_4
represents a straight-chain or branched alkyl group. ] An active energy ray-curable hot-melt pressure-sensitive adhesive composition, further comprising: D, 0.1 to 1 part by weight of an antioxidant.