JPH06116536A - Adhesive tape - Google Patents

Abstract

PURPOSE:To prevent an adhesive from remaining when a releasing tape is peeled on the employment of the adhesive tape or when the adhesive tape is repeeled after adhering to an adherend, by improving an adhesive force between the substrate layer and adhesive layer of the adhesive tape. CONSTITUTION:The adhesive tape is characterized by disposing a primer layer consisting mainly of a polymer produced from an acrylic ester monomer having a primary amino group as a main component or a primer consisting mainly of a rubber composition, a polyester resin and the polymer produced from the acrylic ester monomer having the primary amino group as the main component on the surface of a foam sheet substrate layer comprising a synthetic resin or a synthetic resin film substrate layer, and further forming an adhesive layer comprising an acrylic adhesive agent and a cross-linking agent capable of reacting with the primary amino group of the primer layer component on the primer layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an undercoating agent formed on the surface of a base material layer for improving the adhesion between the base material layer and the pressure sensitive adhesive layer in a pressure sensitive adhesive tape comprising a synthetic resin base material layer.

[0002]

2. Description of the Related Art It is well known that a pressure-sensitive adhesive tape formed by forming a pressure-sensitive adhesive layer on a substrate made of synthetic resin is generally used.

The adhesiveness between the base material layer and the adhesive layer in these adhesive tapes may not be sufficient, and various undercoating agents are used as a means for improving the adhesiveness. For example, when the base material layer is for cellophane, a mixture of niloryl rubber and N-methylol acrylamide (Japanese Patent Publication No. 47-872).
No. 0), for a polyethylene or polypropylene base layer, a mixture of a graft copolymer of rubber and acrylic acid and an isocyanate (Japanese Patent Publication No. 50-201).
No. 08) and a base material layer for polyester, a composition comprising nirolyl rubber and polyamide resin (Japanese Patent Publication No.
No. 18849) has been proposed as an undercoat. A method is also known in which the surface of the base material on which the pressure-sensitive adhesive layer is provided is subjected to corona treatment to improve the adhesion.

[0004]

As described above, the means for increasing the adhesion between the base material layer and the pressure sensitive adhesive layer in the pressure sensitive adhesive tape is to make the surface of the base material layer polar. The improvement of the adhesiveness by the above-mentioned undercoating agent is that the adhesiveness between the base material layer and the pressure-sensitive adhesive layer is not yet sufficient, and when a laminated body such as a pressure-sensitive adhesive tape is used as a product, when peeled off during use. In some cases, the adhesive layer may be left unusable on the back surface of the base material layer and may not be used. Further, there is a problem that adhesive residue is left on the adherend even when it is peeled off again after being attached to the adherend.

Further, a method of improving adhesion by performing corona treatment is that the adhesiveness varies depending on the type of the base layer and the adhesiveness changes with time after the corona treatment. There is a drawback that it is difficult to maintain the quality stability regarding the adhesion between the layer and the pressure-sensitive adhesive layer.

In view of the above problems, the present invention improves the adhesiveness between the base material layer and the pressure sensitive adhesive layer in the pressure sensitive adhesive tape composed of the synthetic resin base material layer, so that when the pressure sensitive adhesive tape is used, An object of the present invention is to provide a pressure-sensitive adhesive tape that does not cause adhesive residue during re-peeling after peeling and after being attached to an adherend.

[0007]

Means for Solving the Problems As a result of earnest analysis to solve the above-mentioned problems, the present inventors have found that the greatest cause of the lack of adhesion between the pressure-sensitive adhesive tape substrate layer and the pressure-sensitive adhesive layer is
The adhesiveness is insufficient because the undercoating agent layer and the pressure-sensitive adhesive layer formed on the surface of the pressure-sensitive adhesive tape substrate layer have only a chemical affinity. Furthermore, when the base material is thin, when it is peeled from the adherend, the base material bends at a considerable angle, so that the undercoat layer does not follow the base material layer.
It was concluded that the above-mentioned both layers are delaminated, resulting in the phenomenon of adhesive residue.

As a result of extensive studies as a method for solving the above-mentioned problems, the present invention shows that a gap between the undercoat layer and the pressure-sensitive adhesive layer is
By increasing the adhesiveness by causing a chemical bond, by designing the composition of the undercoating agent having the followability of the undercoating agent layer to the substrate layer between the adhesive tape substrate layer and the undercoating agent layer. The above purpose has been completed.

That is, according to the present invention, an undercoat layer mainly composed of a polymer mainly composed of an acrylic acid ester monomer having a primary amino group is provided on one surface of a base material layer made of a synthetic resin, and further, A pressure-sensitive adhesive tape comprising an acrylic pressure-sensitive adhesive and a pressure-sensitive adhesive layer comprising a crosslinking agent capable of reacting with a primary amino group of the primer layer component on the primer layer, and a synthetic resin. On one surface of the base material layer made of, an undercoat layer made of a polymer having a primary amino group-containing acrylate monomer as a main component, a rubber composition and a polyester resin is provided, and further on the undercoat layer. A pressure-sensitive adhesive tape comprising an acrylic pressure-sensitive adhesive and a pressure-sensitive adhesive layer comprising a crosslinking agent capable of reacting with the primary amino group of the undercoat layer component.

1) Base Material Layer The base material layer is not particularly limited as long as it is a resin used for ordinary resin tapes, but, for example, polyester, polyolefin and cellophane are preferable. Further, it may be a foam sheet, and examples thereof include synthetic resin foams such as polyethylene, polypropylene, polystyrene and polyvinyl alcohol.

The thickness may be appropriately selected depending on the application.
As a commonly used example, a synthetic resin film preferably has a thickness of 10 to 100 μm from the viewpoint of ease of use. 0.3mm minimum thickness for synthetic resin foam sheet
It can be selected according to the application from the rank.

2) Acrylic Resin Adhesive An acrylic resin adhesive is obtained by copolymerizing an acrylic acid ester having 4 to 12 carbon atoms with a vinyl compound having a functional group.

From the standpoint of sufficiently expressing the characteristics of the pressure-sensitive adhesive, the content of the alkyl acrylate having 4 to 12 carbon atoms is 50 to 95% by weight of the total monomers constituting the acrylic resin-based pressure-sensitive adhesive. preferable. The content ratio of the vinyl compound having a functional group is preferably 0.05 to 20% by weight based on the whole monomers constituting the acrylic resin pressure-sensitive adhesive.

Examples of the alkyl acrylate having 4 to 12 carbon atoms include butyl acrylate, isobutyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, octyl acrylate, lauryl acrylate, methyl acrylate, methyl methacrylate, butyl methacrylate, Examples include isobutyl methacrylate, lauryl methacrylate ethyl acrylate, stearyl acrylate, stearyl methacrylate, isopropyl acrylate, and 2-ethylhexyl methacrylate. Further, styrene, α-methylstyrene, acrylamide, meacrylamide, vinyl acetate, vinyl propionate, acrylonitrile, vinylpyridine and the like may be used as a copolymerization component.

As the vinyl compound having a functional group, carboxylic acid-containing monomers such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, fumaric acid, fumaric acid, maleic acid and maleic anhydride, 2-hydroxyethyl methacrylate, 2 -Hydroxyethyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate and other hydroxyl group-containing monomers and acrylamide, methacrylamide, N-methylol acrylamide, acryl nilolyl and the like.

The acrylic acid ester having 4 to 12 carbon atoms and the vinyl compound having a functional group are obtained by dissolving in a suitable organic solvent and polymerizing by solution polymerization. Examples of usable organic solvents include benzene, toluene, cyclohexane, methyl ethyl ketone,
Examples thereof include ethyl acetate and butyl acetate.

Further, the alkyl acrylate having a carbon number of 4 to 12, the vinyl compound having a functional group and the other monomer may be 1 type or 2 types, respectively, if necessary.
More than one species can be used.

3) Undercoating agent A polymer mainly composed of an acrylic acid ester-based monomer having a primary amino group is mainly used. Such a polymer is composed of an acrylic acid ester having a primary amino group and a functional group. It is obtained by copolymerizing with a vinyl compound.

Here, the acrylic acid ester having a primary amino group means an acrylic acid ester having a primary amino group in the alkyl group, and is represented by the following formula. CH = CH-COOR-NH ₂ (R represents an alkyl group) Examples of vinyl compounds having a functional group include carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid and maleic anhydride. Examples thereof include acid-containing monomers, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate and other hydroxyl group-containing monomers, and acrylamide, methacrylamide, N-methylolacrylamide, acrylonitrile and the like.

Further, as a rubber composition which is a compounding composition of an undercoating agent for improving the followability to the base material layer, natural rubber, synthetic rubber, styrene rubber, butadiene rubber, butyl rubber, nitrile rubber, chloroprene rubber and those Examples thereof include copolymers and mixed systems thereof, but as the undercoating agent component of the present invention, particularly preferable are acrylonitrile-butadiene copolymer and styrene-butadiene copolymer. As the acrylonitrile-butadiene copolymer, those having an acrylonitrile content of 20 to 50% by weight in the copolymer and having Mooney viscosity (JIS standard 6300) of 40 to 110 are preferable. Furthermore, the thing which contains a carboxyl group in the said copolymer can also be used. The styrene-butadiene copolymer has a styrene content of 20.
Those having a Mooney viscosity (JIS standard 6300) of 30 to 80 are preferable in the range of 60 to 60% by weight.
Furthermore, the thing which contains a carboxyl group in the said copolymer can also be used.

The polyester resin is a linear saturated polyester resin produced by the condensation reaction of glycol and a dibasic acid, and preferably has a hydroxyl group or a carboxyl group at the terminal, and more preferably Among the above polyester resins, those having a molecular weight of 10,000 to 40,000 and a glass transition point (Tg) of 20 to 80 ° C. are particularly preferable.

4) Cross-linking agent As a cross-linking agent for acrylic resin-based pressure-sensitive adhesives, an isocyanate-based cross-linking agent and an epoxy group-containing polyglycidyl amine-based cross-linking agent can be cited. However, in the present invention, the one which reacts with the primary amino group containing the primary amino group-containing acrylic acid ester monomer constituting the undercoating agent as the main component is used.

The isocyanate-based crosslinking agent may be a generally known polyisocyanate, for example, tolylene diisocyanate (TDI), hexamethylene diisocyanate, diphenylmethane diisocyanate (M
DI), toluidine diisocyanate, polymethylene polyphenyl polyisocyanate and the like.

As the polyglycidylamine type crosslinking agent,
N.N-diglycidylaniline, N.N-diglycidyltoluidine, mN.N-diglycidylaminophenylglycidyl ether, p-N.N-diglycidylaminophenylglycidyl ether, triglycidyl isocyanate, N.N. N'.N'-tetraglycidylaminodiphenylmethane, N.N.N'.N'-tetraglycidyl-m-xylyleneamine, N.N.N'.N '.
N ″ -pentaglycidyl ethylene triamine and the like can be mentioned.

5) Manufacturing Method When obtaining the pressure-sensitive adhesive tape of the present invention, when the base material layer is comparatively thick, the synthetic resin base material layer is mainly composed of the acrylic acid ester monomer having a primary amino group on one surface thereof. When a thin film-like substrate is used, a polymer containing an acrylic acid ester monomer having a primary amino group as a main component, a rubber composition and a polyester resin are mixed. Is used.

The undercoating agent is applied to the surface of the synthetic resin base material on which the adhesive is provided by a gravure roll and dried to form a thickness of 0.1 to 2 μm. Next, an isocyanate-based crosslinking agent or a polyglycidylamine-based crosslinking agent is added to the acrylic copolymer compound, and then the mixture is stirred so as to be uniform to prepare an acrylic pressure-sensitive adhesive. The amount of the crosslinking agent added is preferably 0.0001 to 2 equivalents, more preferably 0.1 to 1 equivalents, relative to 1 equivalent of the carboxyl group of the acrylic copolymer compound. The acrylic pressure-sensitive adhesive thus obtained is applied to a base material using a normal pressure-sensitive adhesive coating machine, such as a comma coater or knife coater, and dried. As a coating method, a direct method in which the material is directly applied to the base material or a transfer method in which the material once applied to the separator is attached and transferred to the base material may be adopted.

The adhesive tape of the present invention produced as described above is suitable as a packaging tape, a light shielding tape for printing materials, a fixing tape for printing materials, and the like.

[0028]

In the pressure-sensitive adhesive tape of the present invention, the crosslinking agent such as isocyanate and polyglycidylamine epoxy group are grafted to the acrylic ester polymer as the undercoat together with the carboxyl group of the acrylic pressure-sensitive adhesive as the pressure-sensitive adhesive layer. Reacting with the active hydrogen of the primary amino group to generate a chemical bond, so that the undercoat layer and the pressure-sensitive adhesive layer firmly adhere to each other.
Further, the rubber composition and the polyester resin present in the undercoat layer give flexibility to the undercoat layer coating.

[0029]

EXAMPLES Examples of the present invention will be described below. (Embodiment 1) FIG. 1 shows a sectional view of an adhesive tape in Embodiment 1 of the present invention. A 0.8 mm thick polyethylene foam sheet (Softron, manufactured by Sekisui Chemical Co., Ltd.) was used as the base material layer (1), and a primary amino group-grafted acrylic resin (Polyment NK-350, Nippon Shokubai) was used as the undercoat layer (2). (Manufactured by the company) is diluted with toluene to a solid content of 6%, and is applied onto the base material layer (1) by a gravure roll and dried to obtain a solid content of about 1 on the base material layer (1).
An undercoating agent layer (2) having a thickness of μm was formed.

Then, 2 parts by weight of an isocyanate type cross-linking agent (Coronate L-28, manufactured by Nippon Polyurethane Co., Ltd.) was added to 100 parts by weight of an acrylic pressure-sensitive adhesive (Teisan Resin L-4, manufactured by Teikoku Chemical Co., Ltd.). It was stirred for 10 minutes. The pressure-sensitive adhesive prepared by the above method is applied onto the release layer surface of the polyester double-sided release sheet (4) and dried to form a pressure-sensitive adhesive layer (3) having a solid content of 75 μm on the release sheet (4), It was a laminated body. The pressure-sensitive adhesive surface of the laminate and the polyethylene foam sheet base material (1) were superposed by a laminator and wound up to obtain a foam sheet base adhesive tape (5).

(Embodiment 2) FIG. 2 shows a sectional view of an adhesive tape in Embodiment 2 of the present invention. As the undercoat layer (2), a primary amino group-grafted acrylic resin (Polyment NK-
350, manufactured by Nippon Shokubai Co., Ltd.) is diluted with toluene to give 6%.
The solution A having a solid content concentration was used. As a rubber composition, acrylonitrile-butadiene copolymer (Nipol 1432
40 parts of J, manufactured by Nippon Zeon Co., Ltd. and 40 parts of styrene-butadiene copolymer (Nipol 2001, manufactured by Nippon Zeon Co., Ltd.), and further mixed with polyester resin (Vylon RV20).
0, manufactured by Toyobo Co., Ltd.) was mixed with the above rubber composition and diluted with toluene to prepare a B solution having a solid content of 6%.
An undercoating agent was prepared by mixing the above solution A and solution B in a weight ratio of 3: 1.

As the base material layer (1), a single-sided silicone release-treated polyester film (FE2000, having a thickness of 23 μm)
(Manufactured by Nimura Chemical Co., Ltd.) is used to apply the undercoating agent prepared above to the base layer (1) opposite to the release treatment by a gravure roll and then dried to obtain an undercoating agent layer (2) having a solid content of about 1 μm. ) Was formed.

Next, an acrylic adhesive (SK Dyne 7
(02TL, manufactured by Soken Chemical Co., Ltd.) 100 parts by weight of polyglycidylamine-based crosslinking agent (E-AX, manufactured by Soken Chemical Co., Ltd.)
3 parts by weight was added, and the mixture was stirred with a stirrer for 10 minutes. The pressure-sensitive adhesive prepared by the above method is applied to the undercoating agent layer (2) formed on the base material layer (1) by a comma coater,
By drying, a pressure-sensitive adhesive layer (3) having a solid content of 20 μm was formed, and the pressure-sensitive adhesive layer was wound so that the pressure-sensitive adhesive surface was on the inside to obtain a pressure-sensitive adhesive tape (5).

(Comparative Example 1) As Comparative Example 1, instead of the undercoating agent used in Example 1, one side of the polyethylene foam sheet base material used in Example 1 was treated with corona so that the treatment degree was 52 dynes. An adhesive tape was produced in the same manner as in Example 1 except that the above was applied.

Comparative Example 2 As Comparative Example 2, instead of the undercoat used in Example 2 on one side of the polyester film used in Example 1, an acrylonitrile content of 20% was used as a polyester film undercoat. The weight ratio of Niloryl rubber having a Mooney viscosity in the range of 40 to 120 (manufactured by Goodrich Chemical Co.) and polyamide resin having a molecular weight of 3000 to 6500 (manufactured by Firestone Co.) is 3
A pressure-sensitive adhesive tape was prepared in exactly the same manner as in Example 2 except that the solution prepared in 1 was diluted and mixed with toluene to give a 6% solid content solution.

(Evaluation Method 1) FIG. 3 shows an evaluation method for the adhesive residue of the foam-based adhesive tapes (5) of Example 1 and Comparative Example 1. Each adhesive tape of Example 1 and Comparative Example 1 was
Adhesive layers (3) that were cut to a width of 15 mm were adhered to each other, allowed to stand at 50 ° C. and 50% relative humidity for a certain period of time, and then peeled off at a speed of 500 mm / min in the 180 ° direction. The adhesive residue was evaluated visually by the method.

◯: Destruction of the foam sheet base material layer. Δ: Partial interface destruction between the foam sheet base material layer and the adhesive material layer. X: Interface destruction between the foam sheet base material layer and the adhesive layer on the entire surface.

(Evaluation Method 2) FIG. 4 shows an evaluation method regarding adhesive residue of the adhesive tapes of Example 2 and Comparative Example 2. Each of the pressure-sensitive adhesive tapes (5) of Example 2 and Comparative Example 2 was cut into a width of 15 mm and attached to a stainless steel plate as an adherend (7), and allowed to stand for a certain period of time at 50 ° C. and 50% relative humidity. After that, it was peeled off from the stainless steel plate at a speed of 500 mm / min in the 180 ° direction, and the adhesive residue was visually evaluated by the degree of adhesion of the pressure-sensitive adhesive on the stainless steel plate, and the results were defined as follows.

◯: There is no adhesive residue. Δ: There is some adhesive residue. X: Almost the glue is peeled off from the base material layer and adheres to the stainless steel plate.

(Evaluation Method 3) Similarly, each adhesive tape (5) of Example 2 and Comparative Example 2 cut into a width of 15 mm was attached to an acrylic plate as an adherend (7) at 50 ° C.
After a certain period of time under 50% relative humidity, the adhesive sheet was peeled off from the acrylic plate in the 180 ° direction at a speed of 500 mm / min, and the adhesive residue was visually evaluated by the degree of adhesion of the adhesive on the acrylic plate. The result is defined as follows.

◯: No adhesive residue was left. Δ: There is some adhesive residue. X: Most of the glue is peeled off from the base material layer and adheres to the acrylic plate.

(Evaluation Results) The results of the pressure-sensitive adhesive tapes of Examples and Comparative Examples of the present invention carried out in accordance with the above-described evaluation methods are shown in Table 1, Evaluation Methods 2 and 3 for Evaluation Method 1.
Those are shown in Table 2. As is clear from the evaluation results, the adhesive residue is dramatically and stably improved by forming a chemical bond between the undercoating agent and the pressure-sensitive adhesive layer.

Further, in the case of a thin film-like base material, blending the rubber composition and the polyester resin component causes no adhesive residue even when the base material is bent and peeled off.

[0044]

[Table 1]

[0045]

[Table 2]

[0046]

EFFECTS OF THE INVENTION The pressure-sensitive adhesive tape of the present invention is produced by using a polymer having a primary amino group-containing acrylate monomer as a main component on one surface of a base material layer made of a synthetic resin as an undercoating agent. The cross-linking agent in the agent layer cross-links with the pressure-sensitive adhesive layer and the undercoating agent layer to improve the adhesion between the pressure-sensitive adhesive agent layer and the undercoating agent layer.

Further, by blending a rubber composition and a polyester resin component as an undercoating agent, it is possible to provide flexibility capable of following the movement of a base material layer made of synthetic resin, and a base material having a small thickness. Also, the adhesion between the undercoat material layer and the base material layer is improved. In this way, the adhesiveness between the adhesive layer and the base material layer is further improved by improving the adhesiveness with respect to both the base material layer and the adhesive layer, in which the undercoat layer is made of synthetic resin. Therefore, the adhesive tape is easy to use and has no adhesive residue on the adherend when the adhesive tape is peeled off from its own back surface or after being adhered to the adherend and then repeeled.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the structure of an adhesive tape of Example 1.

FIG. 2 is a cross-sectional view showing the structure of an adhesive tape of Example 2.

FIG. 3 is a side view showing an adhesive residue evaluation method of Example 1.

FIG. 4 is a side view showing an adhesive residue evaluation method of Example 2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base material layer 2 Undercoat layer 3 Adhesive layer 4 Release sheet 5 Adhesive tape 6 Release layer 7 Adherend

Claims (2)

[Claims] 1. An undercoat layer mainly comprising a polymer containing an acrylic acid ester monomer having a primary amino group as a main component is provided on one surface of a base layer made of a synthetic resin, and further on the undercoat layer. A pressure-sensitive adhesive tape comprising a pressure-sensitive adhesive layer comprising an acrylic pressure-sensitive adhesive and a crosslinking agent capable of reacting with a primary amino group of the undercoat layer component. 2. An undercoat layer comprising a polymer mainly composed of an acrylic acid ester monomer having a primary amino group, a rubber composition and a polyester resin is provided on one surface of a base material layer made of a synthetic resin, Further, a pressure-sensitive adhesive tape comprising an acrylic pressure-sensitive adhesive and a pressure-sensitive adhesive layer comprising a cross-linking agent capable of reacting with a primary amino group of the primer layer component on the primer layer.