JPH0481479A - Production of tacky tape - Google Patents

Abstract

PURPOSE:To obtain a tacky tape with enhanced adhesion by applying a specific tacky agent composition onto a release sheet, drying the coated sheet, then laminating the formed tacky agent layer to a substrate, further using a specific transfer sheet and transferring the resultant tacky agent layer to the surface of the above-mentioned substrate. CONSTITUTION:An tacky agent composition containing an acrylic acid esterbased polymer as a principal component, a metallic crosslinking agent and a polyisocyanate compound is applied onto a release sheet such as polyethylene terephthalate film, heat-treated and dried. A substrate such as a nonwoven fabric or Japanese paper for constructing an interlayer of a double-sided tape is then laminated to the resultant dried tacky agent layer. Furthermore, the above-mentioned tacky agent composition is applied to one surface of a release sheet and dried to afford a transfer sheet and the formed tacky agent layer of the transfer sheet is subsequently transferred to the surface of the aforementioned substrate to provide a tacky tape improved in adhesion of the tacky agent layer to the interlayer.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a method for producing a double-sided tape in which the adhesive layer is composed of an adhesive composition containing an acrylic acid ester polymer as a main component, and in particular, , relates to a method for producing a double-sided tape with improved adhesion between the adhesive layer and the intermediate layer.

[Conventional technology]

Conventionally, double-sided tapes having an adhesive layer containing an acrylic acid ester polymer as a main component have been manufactured through the following steps. An adhesive composition containing an acrylic ester polymer as a main component and an isocyanate crosslinking agent, an aziridine crosslinking agent, or a metal crosslinking agent is applied onto a release sheet and dried. Next, a base material for constituting the intermediate layer of the double-sided tape, such as a nonwoven fabric, is bonded to the dried adhesive layer to obtain a laminate. Furthermore, a transfer sort obtained by coating and drying the same adhesive composition as above on one side of a release sheet is prepared, and the adhesive layer of the transfer sheet is applied to the exposed side of the base material of the laminate. Transfer to the side surface.

Further, unlike the above-mentioned transfer method, a method is also used in which an adhesive composition is simultaneously applied to both sides of the base material and dried.

Among the crosslinking agents mentioned above, when using isoneate crosslinking agents, the crosslinking reaction may not proceed quantitatively due to environmental influences, etc., whereas with aziridine crosslinking agents and metal crosslinking agents, the crosslinking reaction may not progress quantitatively. It has the advantage that the crosslinking reaction progresses.

[Problem to be solved by the invention]

However, when a metal-based crosslinking agent is used, the curing of the adhesive composition proceeds relatively quickly during the drying process of the adhesive composition, resulting in poor adhesion between the adhesive layer and the base material as an intermediate layer. In addition, there was a problem in that the adhesion between the adhesive layers formed on both sides of the base material through the intermediate layer was reduced.

Therefore, during use, peeling or destruction tends to occur at the interface between the adhesive layer and the intermediate layer, and at the interface between the adhesive layers on both sides with the intermediate layer interposed therebetween.

Therefore, an object of the present invention is to provide a method for producing an adhesive tape in which the adhesion between the adhesive layer and the base material as an intermediate layer and the adhesiveness between the adhesive layers on both sides of the intermediate layer are improved. be.

[Means for Solving the Problems] The method for producing an adhesive tape of the present invention achieves the above-mentioned problems by improving the adhesive composition used to constitute the adhesive layer. It is characterized by comprising a process.

That is, the first invention of the present application includes the steps of coating a pressure-sensitive adhesive composition containing an acrylic ester polymer as a main component, a metal crosslinking agent, and a polyisocyanate compound on a release sheet, and drying the adhesive composition. , a step of laminating a base material for forming an intermediate layer of a double-sided tape onto the dried adhesive layer, and a transfer sheet formed by coating and drying the above-mentioned adhesive composition on one side of a release sheet. and transferring the adhesive layer of the transfer sheet onto the surface of the base material.

Further, in the second invention of the present application, an adhesive composition is used which contains an acrylic ester polymer as a main component, a metal crosslinking agent, and a block type polyisocyanate compound.

As described above, the present invention is characterized by the pressure-sensitive adhesive composition used, and therefore the present invention will be described in more detail below, with emphasis on the pressure-sensitive adhesive composition.

(a) Adhesive composition used The adhesive composition used in the first invention has an acrylic acid ester polymer as a main component, and specifically contains an acrylic resin, a metal crosslinking agent, and It is obtained by mixing a polyisocyanate compound with a solvent. Moreover, the adhesive composition used in the second invention is obtained by mixing an acrylic resin, a metal crosslinking agent, a flock type polyisocyanate compound, and a solvent.

) Acrylic resin that can be used It is possible to use an acrylic resin obtained by copolymerizing an acrylic acid alkyl ester having an alkyl group having 4 to 12 carbon atoms and a vinyl compound having a functional group.

(2) As the acrylic acid alkyl ester, n-phthyl acrylate, isobutyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, octyl acrylate, lauryl acrylate, etc. are used.

Furthermore, if necessary, the following may be added as acrylic acid alkyl esters other than those mentioned above.

Namely, methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate,
2-ethyl hequinyl methacrylate, stearyl (meth)acrylate, n-butyl methacrylate, isobutyl methacrylate or lauryl methacrylate, etc. may be used. In addition, (meth)acrylate is
The term is used to include both methacrylate and acrylate.

Furthermore, it is also possible to copolymerize the above acrylic acid ester with a vinyl monomer such as styrene, α-methylstyrene, vinyl propionate, or vinyl acetate.

The content of the acrylic acid alkyl ester containing an alkyl group having 4 to 12 carbon atoms is approximately 50 to 99.95% by weight of the total monomers constituting the acrylic resin.

■ Vinyl compounds with functional groups acrylic acid, methacrylic acid, itaconic acid, crotonic acid,
Acids or acid anhydrides such as fumaric acid, maleic acid or maleic anhydride; 2-hydroxyethyl (meth)
Hydroxyl group-containing monomers such as acrylate, 2-hydroxypropyl methacrylate, or 2-hydroxybutyl methacrylate; or acrylamide, methacrylamide, N-methylolacrylamide, or acrylonitrile may be mentioned.

The content of the vinyl compound having a functional group is approximately 0.05 to 20 percent of the total monomers constituting the acrylic resin.

■The acrylic resin contained in the adhesive composition containing an acrylic acid ester polymer as a main component contains the above-mentioned acrylic acid alkyl ester, a vinyl compound having a functional group, and other ingredients as necessary. It can be obtained by dissolving the compound in a solvent and polymerizing it by solution polymerization. Examples of organic solvents that can be used include benzene, toluene, cyclohexane, methyl ethyl ketone, ethyl acetate, and butyl acetate. Note that methanol, propatool, butanol, or the like can be used as a diluting solvent. Furthermore, one or more types of acrylic acid alkyl ester, vinyl compound having a functional group, and other monomers may be used.

Adhesive compositions containing acrylic acid ester polymers as main components include tackifiers such as petroleum resins, terpene resins, coumaron-indene resins, or phenol resins, antioxidants, various colorants, antiaging agents, or fillers. Appropriate additives such as the following may be appropriately blended within a range that does not impede the effects of the present invention.

11) Metal-based crosslinking agent The metal-based crosslinking agent used in the present invention is a chelate compound of a polyvalent metal. Examples of metals include Zn,
Cd, Co, Ni, Cu, Ca.

Sn, Ba, Ti, Cr, Mn, Fe, Al, Sl,
Examples include Pb, Zr, Mo, and W.

Examples of compounds that form chelates with the above metals include acetylacetone, methyl acetoacetate, ethyl acetoacetate, ethyl lactate, methyl salicylate, methyl tartrate, 4-hydroxy-4methyl-2-pentanone, jetanolamine, N .

Examples include N-diethylethanolamine and diethyl malonic acid ester.

The metal crosslinking agent is used in an amount of 0.001 to 5.0 parts by weight based on 100 parts by weight of the acrylic resin.

ii) Polyisocyanate compound The polyisonoanate compound used in the first invention of the present application is an organic compound having two or more isocyanate groups in one molecule, and includes aromatic, aliphatic and aliphatic groups. There are ring family members. Alternatively, the compound may be in the form of a prepolymer having a terminal isocyanate (2-) group obtained by reacting a polyol with a polyisocyanate or the like in advance.

Examples of the above polyisocyanate compounds include:
Tolylene diisocyanate and its derivatives, hexaneethylene diisocyanate and its derivatives, diphenylmethane diisocyanate and its derivatives, isophorone diisocyanate and its derivatives, liquid modified diphenylmethane diisocyanate and its derivatives, triphenylmethane triisocyanate, polymethylene polyphenylisocyanate , xylene diisocyanate, cyclohexyl diisocyanate, cyclohexane phenylene diisocyanate, dicyclohexylmethane diisocyanate, naphthalene-1,5-diisocyanate, tris-(
p-isocyanate phenyl) thiophosphite, isopropylbenzene-24-diisocyanate, polyfunctional aromatic isocyanate, polyfunctional aliphatic isocyanate,
Examples include polyfunctional aromatic aliphatic isocyanates, addition compounds of polypropylene glycol and tolylene diisocyanate, and derivatives of each of the exemplified polyisocyanate compounds may also be used.

The polyisocyanate compound is the acrylic resin 100 mentioned above.
It is used in a range of 0.05 to 5.0 parts by weight. This is because if the amount is less than 0.05 parts by weight, the adhesion between the adhesive layer and the intermediate layer will not be improved, and if it exceeds 5.0 parts by weight, other adhesive physical properties will deteriorate.

iv) The blocked polyisocyanate compound used in the second invention of the present application is an organic compound containing two or more isocyanate groups in one molecule, and the isocyanate groups are blocked with a blocking agent. There are aromatic, aliphatic and alicyclic types.

Examples of the above-mentioned block-type polyisocyanate compounds include blocks of tolylene diisocyanate and its derivatives, blocks of hexamethylene diisocyanate and its derivatives, and blocks of isophorone diisocyanate and its derivatives. .

As the blocking agent used to obtain the above-mentioned blocked polyisocyanate compound, methanol, ethanol, phthanol, propatool, phenol, chlorophenol, nitrophenol, acetylacetone, methyl acetoacetate, caprolactam, methyl ethyl ketoxime, etc. are used.

The block polyisocyanate compound is used in an amount of 0.05 to 5.0 parts by weight based on 100 parts by weight of the acrylic resin. This is because if it is less than 0.05 parts by weight, the adhesion between the intermediate layer and the adhesive layer will not be improved, and if it exceeds 5 parts by weight, it will adversely affect other adhesive properties.

No. 1 of this application. In the second invention, the adhesive composition obtained as described above is first applied onto a release sheet and dried. Further, for transfer, the same adhesive layer is also applied and dried on a release sheet prepared separately. As each release sheet used in these steps, an appropriate sheet material whose surface has releasability to the adhesive layer can be used. For example, release paper or a synthetic resin film whose surface has been subjected to mold release treatment can be used.

As the base material for forming the intermediate layer, any suitable material having air permeability, such as nonwoven fabric, Japanese paper, or cloth, which has been conventionally used to obtain double-sided adhesive tapes, can be used.

1 ← (Shi 11 Shi L Mata The first and second inventions of the present application are characterized by improving the above-mentioned pressure-sensitive adhesive composition, and other manufacturing processes are different from conventional methods for obtaining double-sided tapes. It is carried out by an appropriate method commonly used in the field.

[Effect]

In the first invention of the present application, a polyisocyanate compound is added in advance to the adhesive composition, thereby increasing the adhesion between the adhesive layer and the intermediate layer. This is because the base material used as the intermediate layer, such as a nonwoven cellulose fabric, has many hydroxyl groups on its surface, and these hydroxyl groups react with isocyanate, causing the following reaction to occur. This is thought to be due to the formation of bonds.

RNCO+R'OH-+RNH-COOR' Also in the second invention of the present application, it is thought that the block type polyisocyanate compound reacts in the same manner as in the above formula to form a bond, thereby improving adhesion.

In addition, in the case of a polyisocyanate compound to which a blocking agent is not added, there is a risk that it will be decomposed by moisture in the adhesive layer. Therefore, the adhesion is more markedly improved in the case of the second invention using a block type polyisocyanate compound.

Additionally, when a metal crosslinking agent is used, an alcohol-based solvent may be used to reduce the viscosity change of the adhesive over time and extend the pot life. , the alcohol and isocyanate may react, and the effect of improving adhesion may not be sufficient. However,
When a block type polyisocyanate compound is used, the reaction between alcohol and isocyanate is difficult to occur, so that adhesion can be improved more effectively.

〔Effect of the invention〕

According to the first invention of the present application, since a polyisocyanate compound is further added to the adhesive composition which contains an acrylic ester polymer as a main component and contains a metal crosslinking agent, both sides can be coated by a transfer method. When manufacturing tape,
Adhesion between the adhesive layer and the intermediate layer and between the adhesive layers on both sides via the intermediate layer is effectively improved.

In addition, in the second invention of the present application, in particular, since a block type isocyanate compound is added to the adhesive composition,
The adhesion between the adhesive layer and the intermediate layer and the adhesiveness between the adhesive layers via the intermediate layer are further effectively improved.

Therefore, the first part of the present application. According to the second invention, during use, it is possible to effectively suppress the destructive phenomenon between the adhesive layer and the intermediate layer or at the interface between the adhesive layers on both sides.

[Example] The present invention will be described in detail below. In addition, in the following description of Examples and Comparative Examples, parts indicate parts by weight unless otherwise specified.

50 parts of Jinsei Ikushi n-butyl acrylate, 40 parts of 2-ethylhexyl acrylate, 5 parts of vinyl acetate, and 5 parts of acrylic acid were charged into a reaction vessel equipped with a cooling tube, along with 73 parts of ethyl acetate as a solvent. The temperature was raised and the mixture was refluxed for 10 minutes to drive out oxygen. Next, a diluted solution of benzoyl peroxide in ethyl acetate (mixing ratio: 0.05 parts of benzoyl peroxide to 3.7 parts of ethyl acetate) was added dropwise, and after reacting under reflux for 5 hours, further benzoyl peroxide Dilute solution of ethyl acetate (3.0 parts of ethyl acetate to 0.03 parts of benzoyl peroxide)
After aging for 2 hours, 20 parts of propatool was added.

The solid content concentration of the resin solution obtained as above was 4
9.5%, and the viscosity was 15,000 cps (20°C).

A pressure-sensitive adhesive composition is prepared by adding 0.1 part of aluminum acetylacetonate and 0.2 part of Coronate 2507 (trade name, manufactured by Nippon Polyurethane Industries Co., Ltd.; hexamethylene diisocyanate blocked with methyl ethyl ketoxime) to the resin solution and stirring. I got it.

Next, the above adhesive composition was applied to a thickness of 2 as a release sheet.
It was coated on a 5 μm polyethylene terephthalate film (trade name: Lumirror #25, manufactured by Toshi Co., Ltd.) so that the thickness after drying was 50 parts m, and heat-treated at a temperature of 110° C. for 4 minutes.

Next, immediately after the heat treatment, the basis weight of the base material was 14 g,
Non-woven fabric with a thickness of 45 μm (product name manufactured by Nihon Shigyo Co., Ltd., s
PC base paper) at a pressure of 5 kg/cd to obtain a laminate. Next, the same adhesive composition as above was coated on the same release note as above so that the thickness after drying was 50 μm, and heat treatment was performed at a temperature of 110 ° C. for 4 minutes. Thereafter, the adhesive layer was transferred and pressed onto the nonwoven fabric side of the laminate (pressure was 5 kg/cii) to obtain a double-sided adhesive tape.

Futari I Ethyl acrylate...0 parts 2-ethylhexyl acrylate...80 parts Vinyl acetate
... 5 parts itaconic acid
... The solid content concentration was 55.5% in the same manner as in Example 1, except that the composition of the 5-part acrylic resin was changed as described above and that propatool was not added.
A resin liquid with a viscosity of 0% and a viscosity of 20,000 cps (20°C) was obtained.

Add 0.2 acetylacetone zirconium to the above resin solution.
and Coronate L (trade name manufactured by Nippon Polyurethane Industries Co., Ltd.; 3 mol of tolylene diisocyanate and 1.1,1
-) Reaction product with 1 mol of Liftirol Propuff) 0.2 part was added and stirred to obtain an adhesive composition.

Next, an adhesive tape was obtained in the same manner as in Example 1 using the above adhesive composition.

Comparative example 1 n-butyl acrylate...50 parts 2-ethylhexyl acrylate...40 parts Vinyl acetate
... 5 parts acrylic acid
... 5 parts Same as Example 1, solid content concentration 49.5%, viscosity 15000 cps (20°
A resin solution of C) was obtained.

Add 0.0% aluminum acetylacetonate to the resulting resin solution.
A pressure-sensitive adhesive composition was obtained by adding 1 part of the mixture and stirring.

An adhesive tape was obtained in the same manner as in Example 1 using the obtained adhesive composition.

Comparative Example 2 Ethyl acrylate...10 parts 2-
Ethylhexyl acrylate...80 parts Vinyl acetate...5 parts itaconic acid
... 5 parts The solid content was 55.0% in the same manner as in Example 1, except that the composition of the acrylic resin was changed as described above and that propatool was not added.
, a resin solution with a viscosity of 20,000 cps (20° C.) was obtained.

Add 0.0% acetylacetone zirconium to the resulting resin solution.
A pressure-sensitive adhesive composition was obtained by adding 2 parts and stirring.

Next, an adhesive tape was obtained in the same manner as in Example 1 using the obtained adhesive composition.

Example 1.2 and Comparative Example 1. obtained as above.
Each adhesive tape of No. 2 was left for 3 hours at 23°C and 65% relative humidity. Thereafter, the holding force at 80''C was measured, and the results shown in Table 1 below were obtained.

The 80°C holding power was tested under the test conditions specified in JIS 20237, with a load of 1 kgf, a test time of 1 hour, and a test temperature of 80°C.

As is clear from Table 1, in the adhesive tape of Comparative Example 1.2, interfacial failure occurred and the load fell as a result, whereas in Example 1.2, the load did not fall and was excellent. It can be seen that it exhibits holding power. Further, it can be seen that in Example 1, more excellent holding power is exhibited than in Example 2.

Table 1 Patent applicant: Block Chemical Industry Co., Ltd.

Claims (2)

[Claims] (1) A step of applying an adhesive composition containing an acrylic acid ester polymer as a main component, a metal crosslinking agent, and a polyisocyanate compound onto a release sheet and drying it, and the dried adhesive layer. a step of bonding a base material for forming an intermediate layer of the double-sided tape to the adhesive composition; and a step of applying the adhesive composition to one side of a release sheet and using a transfer sheet configured to dry the adhesive composition. A method for producing an adhesive tape, comprising the step of transferring an agent layer onto the base material surface. (2) Coating a pressure-sensitive adhesive composition containing an acrylic ester polymer as a main component, a metal crosslinking agent, and a block polyisocyanate compound onto a release sheet, and drying the adhesive composition; A step of laminating a base material for forming an intermediate layer of the double-sided tape onto the adhesive layer, and drying using a transfer sheet configured by applying and drying the adhesive composition on one side of a release sheet. A method for manufacturing an adhesive tape, comprising the step of transferring the adhesive layer thus obtained to the surface of the base material.