JPH0231753B2 - NENCHAKUZAISOSEIBUTSU - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an adhesive composition suitable for use as an adhesive for adhesive tapes, adhesive sheets, and the like. Because adhesives have good workability, they are used in a wide range of applications, from adhesive tapes and adhesive sheets to industrial materials and construction materials. Conventionally, the above-mentioned adhesives have been solution-type adhesives made by dissolving rubber in a solvent or solution-polymerizing acrylic esters, etc., and emulsion-type adhesives made by emulsion-polymerizing acrylic esters. Since the solvent is volatilized when it is applied to the substrate and dried, there is a risk of fire and it is not sanitary. Emulsion-type adhesives have the disadvantage that the solvent is water, so the drying speed is slow, the production efficiency is low, and it is difficult to obtain adhesives. Products such as adhesive tapes had the disadvantage of poor water resistance. In order to overcome the above-mentioned drawbacks, hot-melt pressure-sensitive adhesives containing acrylic acid ester as a main ingredient have been proposed, but they have the drawbacks of low heat resistance and creep resistance. In view of the above drawbacks, the present invention has been made to provide an adhesive composition, particularly a hot melt type adhesive composition, which has excellent heat resistance and creep resistance when applied. ₂ =
CHCOOR ₁ (in the formula, R ₁ is an alkyl group having 4 to 18 carbon atoms) 90 to 99.95 mol% of the compound (), and the general formula

[Formula] (In the formula, R ₂ is H or CH ₃ , R ₃ is

【formula】

【formula】

[Formula] or

[Formula] and R ₄ is H or CH ₃ . ) Compound () or general formula (In the formula, R ₅ and R ₆ are each H or CH ₃ , and m and n are integers that satisfy the following relationship. When m = 1, n = 2 to 5, and when m = 2 to 6. is present in an adhesive composition mainly comprising a copolymer with 10 to 0.05 mol % of the compound ( ) represented by n=2. General formula used in the present invention CH ₂ =CHCOOR ₁
In the compound () represented by the formula, R ₁ has 4 to 4 carbon atoms.
It is an acrylic ester having an alkyl group of 18, and examples thereof include butyl acrylate, isoamyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, decyl acrylate, dodecyl acrylate, and the like. General formula used in the present invention CH ₂ =CR ₂ −
In the compound () represented by COOR ₃ , R ₂ is H or CH ₃ and R ₃ is

【formula】

【formula】

[Formula] or

[Formula] is an acrylic ester or methacrylic ester having a cyclic unsaturated group in which R ₄ is H or CH ₃ , such as 3(4)-acryloxy-1-cyclopentene (which is 3-acryloxy- 3(4)-Methacryloxy-1-cyclopentene, 3(4)-acryloxy-2-methyl-1-cyclopentene, 4-acryloxy -3-methyl-1-cyclopentene,
3(4)-methacryloxy-2-methyl-1-cyclopentene, 4-methacryloxy-3-methyl-1
-Cyclopentene, 4(5)-acryloxy-1-cyclohexene, 4(5)-methacryloxy-1-cyclohexene, 4(5)-acryloxy-2-methyl-
1-cyclohexene, 4(5)-acryloxy-3-
Methyl-1-cyclohexene, 4(5)-methacryloxy-2-methyl-1-cyclohexene, 4(5)-
Methacryloxy-3-methyl-1-cyclohexene, 5(6)-acryloxybicyclo[2.2.1]-2-
Heptene, 5(6)-methacryloxybicyclo[2.2.1]-2-heptene, 5(6)-acryloxybicyclo[2.2.1]-3-methyl-2-heptene, 5
(6)-acryloxybicyclo[2.2.1]-4-methyl-2-heptene, 5(6)-methacryloxybicyclo[2.2.1]-3-methyl-2-heptene, 5(6)-methacryloxy Bicyclo[2.2.1]-4-methyl-2
-Heptene, 8(9)-acryloxytricyclo[5.2.1.0 ^2,6 ]-4-decene, 8(9)-methacryloxytricyclo[5.2.1.0 ^2,6 ]-4-decene, 8(9) )-acryloxytricyclo[5.2.1.0 ^2,6 ]-2-methyl-4-decene, 8(9)-acryloxytricyclo[5.2.1.0 ^2,6 ]-3-methyl-4-decene, 8 (9)-methacryloxytricyclo[5.2.1.0 ^2,6 ]-2-methyl-4-decene, 8(9)-methacryloxytricyclo[5.2.1.0 ^2,6 ]-3-methyl-4-decene etc. General formula used in the present invention In the compound () represented by the formula, _R5 and _R6 are H or _CH3 , and m and n are n=2 when m=1.
~5, when m = 2 to 6, it is an acrylic ester or methacrylic ester having a cyclic unsaturated group, where n = 2, and when m in the general formula is 1, for example, 2-di Cyclopentenoxyethyl acrylate 2-dicyclopentenoxyethyl methacrylate, 2-dicyclopentenoxypropyl acrylate, 2-dicyclopentenoxypropyl methacrylate, 3-dicyclopentenoxyisobutyl acrylate, 3-dicyclopentenoxyisobutyl methacrylate, Examples include 3-dicyclopentenoxyneopentyl acrylate, 3-dicyclopentenoxyneopentyl methacrylate, and when m is 2 to 6, for example, diethylene glycol-mono-dicyclopentenyl ether acrylate. Diethylene glycol mono-dicyclopentenyl ether methacrylate, triethylene glycol mono-dicyclopentenyl ether acrylate, triethylene glycol mono-dicyclopentenyl ether methacrylate, tetraethylene glycol mono-dicyclopentenyl ether acrylate, tetraethylene glycol- Mono-dicyclopentenyl ether methacrylate, pentaethylene glycol-mono-dicyclopentenyl acrylate, pentaethylene glycol-mono-dicyclopentenyl methacrylate, hexaethylene glycol-mono-dicyclopentenyl ether acrylate, hexaethylene glycol-mono-dicyclo Examples include pentenyl ether methacrylate. And among the above compounds () and (), 8(9)
-acryloxytricyclo[5.2.1.0 ^2,6 ]-4-decene, 8(9)-methacryloxytricyclo[5.2.1.0 ^2,6 ]-4-decene, 2-dicyclopentenoxyethyl acrylate and 2-dicyclopentenoxyethyl methacrylate is preferred because it has excellent adhesive properties. The adhesive composition of the present invention is mainly composed of a copolymer of the above compound () and the compound () or (), and the ratio of the compound () to the compound () or () is such that the ratio of the compound () to the compound () or If the ratio of () is small, the creep resistance will be poor when the adhesive composition is coated on a substrate and dried to produce an adhesive tape, while if it is too large, the adhesive strength will be reduced, so the compound in the copolymer will The ratio of () or () is 0.05 to 10
It is mol%, preferably 0.1 to 7 mol%. If the molecular weight of the above copolymer is high, the heat meltability will decrease, and if it is low, the creep resistance will be poor. Therefore, it is preferable that the weight average molecular weight is 5 x 10 ⁴ to 8 x 10 ⁵ , and the copolymer is applied by melting it. For 10 ⁵ ~ 6 ×
More preferably, it is ¹⁰⁵ . Further, the above copolymer may be copolymerized with other copolymerizable monomers, such as acrylic acid, methacrylic acid, itaconic acid, maleic anhydride, acrylamide, and β-hydroxyethyl acrylate. , β-hydroxy methacrylate,
Hydroxypropyl acrylate, hydroxypropyl methacrylate, styrene, vinyl acetate,
Examples include isobutyl ether, n-butyl ether, etc., and the amount of the monomer added is preferably 65 mol% or less, more preferably 50 mol% of the total of the compound () and compound () or (). It is as follows. Any conventionally known method may be used to synthesize the copolymer, for example, by adding the above compound to an organic solvent such as propanol, methyl cellosolve, butyl cellosolve, butyl cellosolve acetate, ethyl carbitol, acetone, methyl ethyl ketone, ethyl acetate, or toluene. () and compound ()
or () and benzoyl peroxide, t-
It is synthesized by solution polymerization by adding a polymerization initiator such as butyl barbenzoate, di-t-butyl peroxide, cumene hydroperoxide, azobisisobutyronitrile, etc. and heating. After polymerization, the solid content is reduced by heating under reduced pressure.
100% copolymer can be obtained. The pressure-sensitive adhesive composition of the present invention is preferably made into a hot melt type by volatilizing the solvent as described above. The adhesive composition of the present invention is mainly composed of the above-mentioned copolymer, and the above-mentioned copolymer contains a terpene, which is generally added to the adhesive composition when producing adhesive tapes, adhesive sheets, etc. Tackifiers such as phenolic resins, phenolic resins, xylene resins, fillers, coloring agents, etc. may be added. The adhesive composition of the present invention is applied to a substrate such as a vinyl chloride resin film, a polyester film, a polyethylene film, a polypropylene film, cloth, a nonwoven fabric, and dried to be used in adhesive tapes, adhesive sheets, etc. Any method may be adopted as the above coating and drying method, such as a method of coating the solution-polymerized copolymer solution on a substrate and drying it, a method of drying the copolymer solution, and a method of drying the copolymer solution.
Examples include a method of heating and melting a 100% copolymer and applying it. Copolymer is used as the coating method.
Heat to 130~200℃ to melt state, knife over roll coater, fountain die coater,
Examples include a method of coating the substrate with a calender roll coater or the like, and a method of coating the substrate with an extruder equipped with a T-die (so-called direct coating machine). Note that during the above coating, it is preferable to replace the coating atmosphere with nitrogen. The adhesive tapes, adhesive sheets, etc. obtained as described above are preferably crosslinked by ionizing radiation in order to improve heat resistance and creep resistance. The ionizing radiation is radiation that has been conventionally used to crosslink synthetic resins, such as electron beams,
Examples include rays, β rays, and γ rays. The radiation dose may be appropriately determined depending on the required performance of the adhesive tape, label, etc., but is generally preferably 0.3 to 10 megarads, more preferably 0.5 to 5 megarads.
It's Megarad. Since the composition of the adhesive composition of the present invention is as described above, it has good water resistance, heat resistance, adhesion, and creep resistance, and especially when cross-linked by radiation after being applied to a substrate, it has very good creep resistance. It is suitable for use as an adhesive for adhesive tapes, adhesive sheets, etc., and if the solvent is volatilized after solution polymerization,
Since a hot melt type adhesive composition is obtained,
Adhesive tapes, adhesive sheets, etc. can be manufactured safely, hygienically, and efficiently without the risk of fire. Next, the present invention will be explained by examples. The measurement method is as follows. (1) Weight average molecular weight - Prepare a 0.5% tetrahydrofuran solution of the sample and use Waters GPC.
It was measured by gel vermi-ation chromatography using a -200 model machine. (2) SP adhesive strength - width 15mm on stainless steel plate
The sample was pasted and pressed with a 2 kg rubber roll 5 times, and after being left for 15 minutes, it was pressed at a speed of 300 mm/min.
The film was peeled off at 180° and the peel strength was measured. (3) Measured according to Ball Tatsuku J. Dow method. (4) Holding power at 40℃ - Width 15mm on stainless steel plate
A sample of 10 mm is pasted, a 2 Kg rubber roll is pressed back and forth once, and after leaving it for 15 minutes, a stainless steel plate is hung, a 1 Kg weight is hung from the bottom of the sample, and the time required for the weight to fall ( minutes) was measured. Example 1 1200 g of toluene was charged into a polymerization reactor equipped with a stirrer, a thermometer, a cooling tube, and a nitrogen introduction tube, and the temperature was raised to 70° C. while purging with nitrogen. Butyl acrylate 368g (2.90mol) Ethyl acrylate 12g (0.14mol) Acrylic acid 14g (0.19mol) 8-Acryloxytricyclo[5.2.1.0 ^2,6 ]-4
-Decene 2g (0.01 mol) Azobisisobutyronitrile 0.4g Next, a blend having the above composition was added, and the mixture was reacted for 12 hours while being kept at 70°C while purging with nitrogen to obtain a copolymer solution. The polymerization rate was 99.5%. The resulting copolymer solution was distilled under reduced pressure and vacuum dried to obtain an adhesive composition with a solid content of 100%. The weight average molecular weight of the obtained pressure-sensitive adhesive composition was 2.3×10 ⁵ , and the melt viscosity at 160° C. was 8.0×10 ⁴ CPS. The obtained adhesive composition was supplied to a fountain die coating machine and coated on a polyester film (thickness: 25 μm) to a thickness of 40 μm at 160° C. to obtain an adhesive tape.
Next, the resulting adhesive tape was irradiated with a 2 megarad electron beam using an electron beam accelerator to obtain a crosslinked adhesive tape. The SP adhesive strength of the obtained adhesive tape is 830g/15mm width.
The ball tack was 16, the holding power was 3 minutes, the SP adhesion of the crosslinked adhesive tape was 850 g/15 mm width, the ball tack was 15, and the holding power at 40°C was over 5000 minutes. Example 2 Ethyl acetate was added to the polymerization reactor used in Example 1.
A copolymer solution was obtained in the same manner as in Example 1 by adding 1200 g of the copolymer and adding a blend having the following composition.
The polymerization rate was 99.5%. 2-ethylhexyl acrylate
372g (2.02mol) Ethyl acrylate 12g (0.14mol) Acrylic acid 12g (0.17mol) 2-dicyclopentenoxyethyl acrylate
4 g (0.02 mol) Azobisisobutyronitrile 2 g The obtained copolymer solution was dried in the same manner as in Example 1 to obtain an adhesive composition with a solid content of 100%. The weight average molecular weight of the obtained adhesive composition is
3.5×10 ⁵ and the melt viscosity at 170℃ is 10.5×
It was 10 ⁴ CPS. The obtained adhesive composition was supplied to a fountain die coating machine and applied to a polyester film (thickness: 25 μm) to a thickness of 40 μm at 170° C. to obtain an adhesive tape. Next, the adhesive tape was irradiated with a 2 megarad electron beam using an electron beam accelerator to obtain a crosslinked adhesive tape. The SP adhesive strength of the adhesive tape is 810g/15mm width, the ball tack is 14, and the holding power at 40℃ is 2 minutes.The SP adhesive strength of the crosslinked adhesive tape is 790g/15mm width, the ball tack is 14.
The holding power at 15 and 40°C was more than 5000 minutes. Examples 3 to 5 Using the solvents and compounds shown in Table 1, copolymerization was carried out in the same manner as in Examples 1 and 2, followed by drying to obtain an adhesive composition and an adhesive tape. Table 1 shows the weight average molecular weight, melt viscosity at 150° C., and electron beam irradiation dose of the resulting pressure-sensitive adhesive composition.
In addition, we measured the SP adhesive strength, ball tack, and 40°C holding strength of the adhesive tape before and after crosslinking with electron beams.
Shown in the table.

【table】

【table】

Claims (1)

[Claims] 1 Compound ()90 represented by the general formula CH ₂ =CHCOOR ₁ (in the formula, R ₁ is an alkyl group having 4 to 18 carbon atoms)
~99.95 mol%, and the general formula [Formula] (wherein R ₂ is H or CH ₃ , R ₃ is [Formula] [Formula] [Formula] or [Formula], and R ₄ is H or CH ₃ . ) Compound () or general formula (In the formula, R ₅ and R ₆ are each H or CH ₃ , and m and n are integers that satisfy the following relationship. When m = 1, n = 2 to 5, and when m = 2 to 6. A pressure-sensitive adhesive composition mainly comprising a copolymer with 10 to 0.05 mol % of a compound () represented by n=2. 2. The pressure-sensitive adhesive composition according to claim 1, wherein the compound () is 8(9)-acryloxytricyclo[5.2.1.0 ^2.6 ]-4-decene. 3. The pressure-sensitive adhesive composition according to claim 1, wherein the compound () is 2-dicyclopentenoxyethyl acrylate. 4 The weight average molecular weight of the copolymer is 5×10 ⁴ to 8×
10 ^5. The pressure-sensitive adhesive composition according to claim 1, 2 or 3, wherein the adhesive composition is 10 5.