JPH10330700A - Adhesive tape - Google Patents

Abstract

(57) [Summary] [PROBLEMS] When exposed to a high-temperature atmosphere in a state in which adhesive tapes are overlapped and adhered, floating or peeling of the adhesive tape does not occur in the overlapped area, and the adhesive tape is covered. When peeling from the adherend, the pressure-sensitive adhesive layer can smoothly peel the pressure-sensitive adhesive tape from the adherend without causing cohesive failure, and can be smoothly rewound from the pressure-sensitive adhesive tape roll. Provide tape. SOLUTION: A back treatment layer containing a long-chain alkyl ethylene urea as an essential component is formed on one surface of a substrate, and an alkyl group having an average of 4 to 12 carbon atoms in the alkyl group on the other surface. A pressure-sensitive adhesive layer is formed by forming a pressure-sensitive adhesive layer mainly containing a copolymer obtained by copolymerizing a monomer mixture containing the compound and a functional monomer copolymerizable therewith by emulsion polymerization.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an adhesive tape,
More particularly, the present invention relates to an adhesive tape for masking, which is used particularly when painting automobiles and the like.

[0002]

2. Description of the Related Art Conventionally, an adhesive tape has been used for a masking operation in a coating process of various articles. As an adhesive tape used for the above-mentioned masking operation, that is, a so-called adhesive tape for masking, for example, a tape in which an adhesive layer is formed on one surface of a porous base material such as Japanese paper is known.

When a wide masking area is required for an adhesive tape used for a masking operation, a plurality of adhesive tapes may be overlapped and bonded together. In this case, another adhesive tape is overlapped on a part of the back surface of the adhesive tape previously attached to the adherend. At this time, in order to prevent problems such as intrusion of paint from the adhesive tape overlapping region, adhesion in the adhesive tape overlapping region is required, and specifically,
It is necessary that the adhesive strength between the back surface of the adhesive tape previously attached to the adherend and the adhesive layer of the adhesive tape to be overlaid (hereinafter referred to as self-back surface adhesive force) is high.

On the other hand, the adhesive tape is often provided in a state wound in a roll, and the adhesive tape is used by rewinding a required amount from a wound body. At this time, a peeling treatment is usually performed on the back surface of the adhesive tape for the purpose of smoothly rewinding from the wound body. In masking adhesive tapes, peeling treatment may be performed on the back of the adhesive tape, but in this case, the above-mentioned self-back surface adhesive force is reduced, paint enters from the overlapping area of the adhesive tape, and a sufficient masking function is performed. There was a problem that it could not be achieved.

In order to improve the above-mentioned problems in the pressure-sensitive adhesive tape, a technique using a long-chain alkyl ethylene urea or an N-methylolated higher fatty acid amide together with a reactive polymer as a release treating agent is disclosed in Japanese Patent Application Laid-Open No. Sho 52-6385. And JP-A-52-14635. The pressure-sensitive adhesive tape obtained by treating the rear surface of the pressure-sensitive adhesive tape with such a peeling treatment agent has a proper unwinding property from the wound body and a self-back surface adhesive force.

[0006]

However, in recent years,
The functions required of the adhesive tape for masking are becoming more sophisticated, and the adhesive tape is exposed to a high-temperature atmosphere of about 80 ° C. in a state where the adhesive tape is attached to an adherend, for example, in a coating process of an automobile body. In such a case, with the conventional adhesive tape for masking, the adhesive tape may be lifted or peeled off in the overlapping application area, and a trouble may occur in the coating process. Furthermore, when the adhesive tape is peeled off after the coating operation is completed, the adhesive tape cannot be peeled off smoothly from the surface of the adherend, causing the adhesive layer to undergo cohesive failure and leave the adhesive on the surface of the adherend ( (So-called glue residue).

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object the purpose of, for example, a method in which a plurality of adhesive tapes are laminated on one adhesive tape back surface, such as an adhesive tape for masking. To provide a pressure-sensitive adhesive tape that does not float or peel off in a region where the pressure-sensitive adhesive tape is overlapped even when exposed to a high-temperature atmosphere with the pressure-sensitive adhesive tape laminated. When the adhesive tape is peeled off after being exposed to a high-temperature atmosphere with the adhesive tape attached to the adherend, the adhesive tape does not cause cohesive failure and the adhesive tape is adhered to the surface of the adherend. To provide an adhesive tape that can be peeled off smoothly from the adhesive tape.
Another object of the present invention is to provide an adhesive tape that can be smoothly rewound from an adhesive tape wound body.

[0008]

Means for Solving the Problems In order to solve the above problems, the present inventors have conducted intensive studies on the back treatment layer and the pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive tape. A monomer mixture of a back treatment layer containing as a main component and an alkyl (meth) acrylate containing a functional monomer as an essential component as a main component of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer was emulsion-polymerized. The present inventors have found that the above problems can be solved by preparing an adhesive tape using a copolymer, and have reached the present invention.

That is, the present invention is an adhesive tape having a back surface treatment layer formed on one surface of a substrate and an adhesive layer on the other surface, wherein the back surface treatment layer contains a long-chain alkylethylene urea as an essential component. At the same time, the main component of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is a (meth) acrylic acid alkyl ester having an alkyl group having 4 to 12 carbon atoms on average and a functional monomer copolymerizable therewith. It is a copolymer obtained by copolymerizing a monomer mixture containing the same by emulsion polymerization (claim 1). Further, the functional monomer copolymerizable with the alkyl (meth) acrylate ester may have at least one functional group selected from a carboxyl group, a hydroxyl group, an epoxy group, an amino group, a mercapto group or an isocyanate group in the molecule. The present invention relates to a pressure-sensitive adhesive tape (claim 2) composed of a monomer having a kind of functional group.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The pressure-sensitive adhesive tape of the present invention includes a base material, a pressure-sensitive adhesive layer formed on one surface of the base material, and a back surface treatment layer formed on the surface of the base material opposite to the surface on which the pressure-sensitive adhesive layer is formed.

The substrate used in the present invention can be appropriately selected from those conventionally used as a substrate for an adhesive tape, and is not particularly limited. Examples include paper made of fibrous substances such as Japanese paper, crepe paper, and kraft paper, cloth made of sfumosulin, cotton cloth, synthetic fiber woven cloth, and the like, and plastic films made of polyester, polypropylene, polyethylene, polyvinyl chloride, and the like. Above all, as a substrate used for adhesive tape for masking, the point that the required amount can be easily cut off by hand at the time of work, the paint adhered to the back of the adhesive tape drops on the painted surface when spraying paint It is preferable that the porous base material is used, since it is held on the back without being used. As such a porous base material, a paper material made of the above fibrous substance, particularly a beaten wood pulp, or a porous thin paper material obtained by mixing one or more synthetic short fibers with the paper material is preferable. , Elongation and the like are preferred. Examples of the synthetic short fibers include polyvinyl alcohol (vinylon), polyamide (nylon), polyester, polyethylene, polypropylene, polyurethane, polyvinyl chloride, polyvinylidene chloride, and polyacrylonitrile. The thickness of the substrate is generally 10 to 150 μm, preferably 25 to 1 μm.
00 μm. Undercoating treatment, filling treatment,
Those that have been subjected to a known treatment such as a corona treatment can be used.

A pressure-sensitive adhesive layer is formed on one side of the base material. In the present invention, the main component of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is a (meth) acrylic acid alkyl ester having an alkyl group having 4 to 12 carbon atoms on average and a functional monomer copolymerizable therewith. It is necessary that the monomer mixture is a copolymer obtained by copolymerizing the monomer mixture by emulsion polymerization. here,
The main component includes, in addition to the copolymer, as necessary, various additives such as a tackifier, a crosslinking agent, a plasticizer, a softener, a filler, a pigment, a dye, and an antioxidant. It means that you can stay.

The above alkyl group has an average of 4 to 12 carbon atoms.
Examples of the alkyl (meth) acrylate include butyl (meth) acrylate and 2 (meth) acrylic acid.
-Ethylhexyl, isononyl (meth) acrylate,
Examples thereof include isooctyl (meth) acrylate and lauryl (meth) acrylate. One or more of these alkyl (meth) acrylates are used. These alkyl (meth) acrylates account for at least 50% by weight, preferably 70 to 99%, in the monomer mixture.
%, More preferably 90 to 99% by weight. If it is less than 50% by weight, it may not be possible to obtain good self-back surface adhesive strength.

In the present invention, the functional monomer used as an essential component of the copolymer together with the alkyl (meth) acrylate includes a carboxyl group,
A copolymerizable monomer having a functional group such as a hydroxyl group, an epoxy group, an amino group, a mercapto group, or an isocyanate group. Examples of these functional monomers include acrylic acid, methacrylic acid, itaconic acid, maleic anhydride, crotonic acid, maleic acid, fumaric acid, hydroxyalkyl (meth) acrylate, glycerin dimethacrylate, and glycidyl (meth) acrylate. , Methyl glycidyl methacrylate, aminoethyl (meth) acrylate, 2-
And methacryloyloxyethyl isocyanate. Further, a mercapto group at the terminal of the chain transfer agent or the like can be introduced into the copolymer as a functional group. Among these functional monomers, a carboxyl group-containing monomer is preferable from the viewpoint of the reactivity of the copolymerization reaction, particularly acrylic acid,
Methacrylic acid is preferred.

The functional monomer is contained in the monomer mixture in an amount of from 1 to 1
It is desirable to use 0% by weight, preferably 1 to 4% by weight. If it is less than 1% by weight, good self-back surface adhesive strength may not be obtained, and if it exceeds 10% by weight, the unwinding force when the adhesive tape is wound tends to be large.

In the present invention, the copolymer used as a main component of the pressure-sensitive adhesive includes, in addition to the alkyl (meth) acrylate and the functional monomer, methyl methacrylate, ethyl acrylate, and isopropyl acrylate. And the like. Alkyl groups having 1 to 3 carbon atoms, such as alkyl (meth) acrylates, tridecyl methacrylate, and stearyl (meth) acrylate have 13 to 1 carbon atoms.
8, (meth) acrylic acid alkyl ester, triethylene glycol diacrylate, ethylene glycol dimethacrylate, trimethylolpropane tri (meth) acrylate and other polyfunctional monomers, vinyl acetate, styrene, (meth) acrylonitrile, N-vinyl Other monomers such as pyrrolidone, (meth) acryloylmorpholine, cyclohexylmaleimide, isopropylmaleimide, and (meth) acrylamide may be used as necessary as constituents of the copolymer.

The copolymer used as a main component of the pressure-sensitive adhesive must be obtained by copolymerizing the above-mentioned monomer mixture by an emulsion polymerization method. In the present invention, by preparing a pressure-sensitive adhesive tape by combining a pressure-sensitive adhesive containing a copolymer obtained by an emulsion polymerization method as a main component, and a back surface treatment layer containing a long-chain alkylethylene urea described below as an essential component. In addition, it is possible to prevent a decrease in self-back surface adhesive force when exposed to a high-temperature atmosphere and prevent cohesive failure of the pressure-sensitive adhesive layer when the pressure-sensitive adhesive tape is peeled off from the adherend.
The weight-average molecular weight of the uncrosslinked portion of the copolymer obtained by emulsion polymerization of the monomer mixture is said to be compatible with maintaining the self-back surface adhesive force and preventing cohesive failure of the pressure-sensitive adhesive layer when exposed to a high temperature atmosphere. From the point, it is usually 400,000 to 3,000
000, preferably 500,000 to 2,000,
000 is desirable.

The emulsion polymerization method is not particularly limited, such as polymerization conditions. The emulsion polymerization method is usually carried out at a polymerization temperature of 30 by a general batch polymerization method, continuous drop polymerization method, split drop polymerization method, or the like.
The polymerization can be carried out within the range of -80 ° C.

The polymerization initiator used for the emulsion polymerization is not particularly limited, but for example, 2,2'-
Azobisisobutyronitrile, 2,2′-azobis (2
-Amidinopropane) dihydrochloride, 2,2'-
Azobis (N, N'-dimethyleneisobutylamidine)
Azo compounds, such as potassium persulfate and ammonium persulfate, benzoyl peroxide, t-
Organic peroxides such as butyl hydroperoxide; and redox initiators such as persulfate and sodium bisulfite.

The emulsifier used in the emulsion polymerization is not particularly limited. Examples thereof include sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium polyoxyethylene alkyl ether sulfate, and polyoxyethylene alkyl phenyl ether. Examples include anionic emulsifiers such as sodium sulfate, and nonionic emulsifiers such as polyoxyethylene alkyl ether and polyoxyethylene alkyl phenyl ether. One or more emulsifiers can be used in combination. In both cases of the anionic emulsifier and the nonionic emulsifier, a radical polymerizable emulsifier into which a propenyl group or the like is introduced may be used.

The pressure-sensitive adhesive layer may contain various components such as a tackifier, a cross-linking agent, a plasticizer, a softener, a filler, a pigment, a dye, an antioxidant, and the like, if necessary, for the copolymer obtained by emulsion polymerization. It is formed by applying a mixture of additives to a substrate by a method known per se such as a gravure coater and drying by heating. Alternatively, a pressure-sensitive adhesive layer may be formed by applying a pressure-sensitive adhesive to a release paper having a surface subjected to a release treatment, drying by heating, and then transferring the pressure-sensitive adhesive to a substrate. The thickness of the pressure-sensitive adhesive layer is not particularly limited, but is usually 5 to 5.
It is 50 μm, preferably 10 to 45 μm.

The pressure-sensitive adhesive tape of the present invention has a back surface treatment layer formed on the surface of the substrate opposite to the surface on which the pressure-sensitive adhesive layer is formed. In the present invention, the back surface treatment layer needs to contain a long-chain alkylethylene urea represented by the following formula (1) as an essential component.

[0023]

Embedded image

The alkyl group represented by R in the above formula (1) has 10 to 30 carbon atoms, preferably 14 to 26 carbon atoms.
And the structure may be linear or branched. Examples of the long-chain alkyl ethylene urea include tetradecyl ethylene urea, heptadecyl ethylene urea, and octadecyl ethylene urea. Above all, from the viewpoint of compatibility between self-back surface adhesive strength and moderate adhesive tape rewinding property,
Octadecyl ethylene urea is preferred.

The back surface treatment layer may be composed of only the long-chain alkyl ethylene urea, or may be composed of other resin such as acrylic, urethane or polyester resin or ethylene-vinyl acetate copolymer. May be configured as a mixture with the additive component. When the base material of the pressure-sensitive adhesive tape is a paper material made of a fibrous substance such as kraft paper, crepe paper, or Japanese paper, the back surface treatment layer is formed by a mixture of a backsize agent and a long-chain alkylethylene urea. Can be configured. With such a configuration,
It is possible to simultaneously improve the strength, elongation, and surface smoothness of the paper material, and provide the self-back surface adhesive force and the rewinding property. Examples of the back size agent include, but are not particularly limited to, vinyl acetate resins, acrylic resins, styrene-butadiene rubber (SBR) resins, and the like.
General materials can be appropriately selected and used as these backsize agents. When a long-chain alkyl ethylene urea is blended in the back sizing agent, the back sizing agent 100
The mixing amount of the long-chain alkyl ethylene urea is 0.1 part by weight.
It is desirable to use 5 to 30 parts by weight, preferably 1 to 25 parts by weight. The amount of long-chain alkyl ethylene urea is 0.
If the amount is less than 5 parts by weight, good adhesive tape rewinding properties may not be obtained. If the amount is more than 30 parts by weight, the long-chain alkylethylene urea may migrate to the adhesive layer and reduce the adhesive properties.

The back treatment layer is prepared by diluting a composition containing a long-chain alkyl ethylene urea as an essential component in a suitable solvent such as ethyl acetate, toluene, hexane, heptane, etc.
Alternatively, the composition is formed by applying an aqueous dispersion, applying the composition to a surface of the substrate opposite to the surface on which the pressure-sensitive adhesive layer is formed, by a known method such as a gravure coater, and drying by heating. The application amount of the back surface treatment layer is not particularly limited, but is usually 0.5 to 20 g / m ² , preferably 1 to 15 g / m ² .

The pressure-sensitive adhesive tape of the present invention is generally prepared by winding a pressure-sensitive adhesive tape having a back surface treatment layer formed on one side of a substrate and a pressure-sensitive adhesive layer on the other side thereof around a core such as a paper tube or a plastic tube. Provided by

The pressure-sensitive adhesive tape of the present invention is not limited to masking applications, but can be used for various purposes such as office use and packaging. Even when used for these purposes, the same effects as described above can be obtained. Needless to say.

[0029]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to Examples. In the following, all parts are parts by weight.

Example 1 A reactor equipped with a thermometer, a stirrer, a nitrogen inlet tube and a reflux condenser was charged with 50 parts of water and 0.2 parts of potassium persulfate, and was purged with nitrogen for 1 hour while stirring. Here, 97 parts of 2-ethylhexyl acrylate, 3 parts of acrylic acid,
Emulsion polymerization treatment was carried out for 3 hours at a polymerization temperature of 70 ° C., while 2 parts of sodium lauryl sulfate and 1 part of polyoxyethylene lauryl ether were emulsified with 100 parts of water, followed by aging at 70 ° C. for 2 hours. Then, the mixture was cooled to room temperature and neutralized with 10% aqueous ammonia to obtain a copolymer emulsion. Solid content 1 of this copolymer emulsion
With respect to 00 parts, 0.1 part of an epoxy crosslinking agent was added,
The adhesive was prepared by mixing well. Basis weight 30
g / m ² of Japanese paper is coated with an acrylic backsize agent (trade name: AE318, manufactured by Nippon Synthetic Rubber Co., Ltd.) and dried at 130 ° C. for 3 minutes to give a coating amount of 10 g / m 2.
After forming the sealing layer of No. ² , octadecylethylene urea (trade name: Octex EM, manufactured by Hodogaya Chemical Industry Co., Ltd.) is applied to the surface of the sealing layer, and dried at 130 ° C. for 3 minutes. Formed a back surface treatment layer of 1 g / m ² . An adhesive is applied to the opposite side of the Japanese paper on which the filling layer and the back surface treatment layer are formed, and dried in a hot air drier at 130 ° C. for 3 minutes to form an adhesive layer having a thickness of 20 μm. An adhesive tape of the invention was produced.

Example 2 Japanese paper having a basis weight of 30 g / m ² was used as a base material, and an acrylic backsize agent (trade name: AE318,
To 100 parts of Nippon Synthetic Rubber Co., Ltd., 100 parts of octadecylethylene urea (trade name: Octex EM, manufactured by Hodogaya Chemical Industry Co., Ltd.) was coated with 5 parts (in terms of solid content), and a composition was applied. Dry for 3 minutes and apply 10
A pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that a back surface treatment layer of g / m ² was formed.

Example 3 A reactor equipped with a thermometer, a stirrer, a nitrogen inlet tube and a reflux condenser was charged with 50 parts of water and 0.2 parts of potassium persulfate, and was purged with nitrogen for 1 hour while stirring. A solution obtained by emulsifying 98 parts of butyl acrylate, 2 parts of acrylic acid, 2 parts of sodium lauryl sulfate, and 1 part of polyoxyethylene lauryl ether with 100 parts of water was added dropwise at a polymerization temperature of 70 ° C. for 3 hours. And then aged at 70 ° C. for 2 hours.
% Of aqueous ammonia to obtain a copolymer emulsion. An adhesive was prepared by adding 0.1 part of an epoxy-based crosslinking agent to 100 parts of the solid content of the copolymer emulsion and mixing well. The pressure-sensitive adhesive was applied to the opposite side of the Japanese paper on which the filling layer and the back surface treatment layer were formed under the same conditions as in Example 1 and dried at 130 ° C. for 3 minutes in a hot air drier to have a thickness of 20 μm. To form a pressure-sensitive adhesive layer of the present invention, thereby preparing a pressure-sensitive adhesive tape of the present invention.

Example 4 An adhesive tape was produced in the same manner as in Example 3 except that Japanese paper on which a back surface treatment layer was formed was used under the same conditions as in Example 2 as a base material.

Example 5 A reactor equipped with a thermometer, a stirrer, a nitrogen inlet tube and a reflux condenser was charged with 50 parts of water and 0.2 parts of potassium persulfate, and was purged with nitrogen for 1 hour while stirring. Here, 94 parts of 2-ethylhexyl acrylate, 5 parts of ethyl acrylate, 1 part of acrylic acid, 2 parts of sodium lauryl sulfate,
Emulsion polymerization treatment was carried out for 3 hours at a polymerization temperature of 70 ° C. while dropping a mixture obtained by emulsifying 1 part of polyoxyethylene lauryl ether with 100 parts of water, and further aged at 70 ° C. for 2 hours, and then to room temperature. The mixture was cooled and neutralized with 10% aqueous ammonia to obtain a copolymer emulsion. An adhesive was prepared by adding 0.1 part of an epoxy-based crosslinking agent to 100 parts of the solid content of the copolymer emulsion and mixing well. The pressure-sensitive adhesive was applied to the opposite side of the Japanese paper on which the filling layer and the back surface treatment layer were formed under the same conditions as in Example 1 and dried at 130 ° C. for 3 minutes in a hot air drier to have a thickness of 20 μm. To form a pressure-sensitive adhesive layer of the present invention, thereby preparing a pressure-sensitive adhesive tape of the present invention.

Example 6 Japanese paper having a basis weight of 30 g / m ² was used as a base material, and an acrylic backsize agent (trade name: AE318,
To 100 parts of Nippon Synthetic Rubber Co., Ltd., 100 parts of octadecylethylene urea (trade name: Octex EM, manufactured by Hodogaya Chemical Industry Co., Ltd.) was coated with a composition prepared by mixing 10 parts (in terms of solid content). Dry for 3 minutes and apply 1
A pressure-sensitive adhesive tape was produced in the same manner as in Example 5, except that a back surface treatment layer of 0 g / m2 was formed.

Comparative Example 1 Japanese paper having a basis weight of 30 g / m ² was used as a base material, and an acrylic backsize agent (trade name: AE318,
(Nippon Synthetic Rubber Co., Ltd.)
A pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that the coating was dried for 10 minutes to form a filling layer having a coating amount of 10 g / m ² .

COMPARATIVE EXAMPLE 2 A reactor equipped with a thermometer, a stirrer, a nitrogen inlet tube and a reflux condenser was charged with 50 parts of water and 0.2 parts of potassium persulfate, and purged with nitrogen for 1 hour while stirring. A solution obtained by emulsifying 90 parts of 2-ethylhexyl acrylate, 10 parts of butyl acrylate, 2 parts of sodium lauryl sulfate, and 1 part of polyoxyethylene lauryl ether with 100 parts of water was added dropwise at a polymerization temperature of 70 ° C. And then aged at 70 ° C. for 2 hours, cooled to room temperature and neutralized with 10% aqueous ammonia to obtain a copolymer emulsion. This copolymer emulsion was applied under the same conditions as in Example 1 to the opposite side of the Japanese paper on which the filling layer and the back surface treatment layer had been formed.
A drying treatment was performed at 30 ° C. for 3 minutes to form a pressure-sensitive adhesive layer having a thickness of 20 μm to prepare a pressure-sensitive adhesive tape.

Comparative Example 3 97 parts of 2-ethylhexyl acrylate, 3 parts of acrylic acid, 2,2'-azobisisobutyronitrile were placed in a reactor equipped with a thermometer, a stirrer, a nitrogen inlet tube and a reflux condenser. 0.2 parts and 230 parts of ethyl acetate were charged and polymerized at 60 ° C. for 8 hours to obtain an adhesive solution. Solid content of this adhesive solution 1
With respect to 00 parts, 0.1 part of an epoxy crosslinking agent was added,
The adhesive was prepared by mixing well. The pressure-sensitive adhesive was applied to the opposite side of the Japanese paper on which the filling layer and the back surface treatment layer were formed under the same conditions as in Example 1;
Drying treatment was performed at 30 ° C. for 3 minutes to form a pressure-sensitive adhesive layer having a thickness of 20 μm, thereby preparing a pressure-sensitive adhesive tape of the present invention.

With respect to the pressure-sensitive adhesive tapes obtained in Examples 1 to 6 and Comparative Examples 1 to 3, a self-back surface adhesive force, a heat resistance and a pressure-sensitive tape unwinding force test were performed at high temperatures by the following methods. . These results were as shown in Table 1.

<Adhesive Strength of Self-Back Side> An adhesive tape (18 mm in width) was attached to a stainless steel plate, and an adhesive layer of the same kind of adhesive tape (18 mm in width) was superimposed on the back surface (the surface of the back treatment layer) of the adhesive tape. Press and reciprocate once with a 2 kg roller and leave at room temperature (23 ° C.) for 15 minutes. Then 80
At 15 ° C. for another 15 minutes.
Peeling angle 180 °, peeling speed 300mm /
The peeling force when the pressure-sensitive adhesive tape on the side overlapped by min was peeled from the back surface of the other pressure-sensitive adhesive tape was measured by a tensile tester, and this was defined as the self-back surface adhesive force.

<Heat resistance> An adhesive tape was applied to a melamine coated plate, and a lacquer paint was sprayed on the plate to form a 100
C. for 1 hour in a hot air oven and dried. Immediately after taking out from the hot air oven, the adhesive tape was peeled off from the melamine coated plate, and the state of the adhesive residue on the melamine coated plate was visually judged in the following stages. ：: No adhesive residue. Δ: Glue residue is partially present. ×: Adhesive residue is present on the entire surface.

<Rewinding force> An adhesive tape having a width of 18 mm and a length of 20 m was wound around a paper tube, and the adhesive tape was rewound using a rewinding tester in accordance with JIS Z0237. The measurement was performed at a speed of 30 m / min.

[0043]

[Table 1]

As is clear from Table 1, the pressure-sensitive adhesive tapes of the examples maintain a high self-back surface adhesive force even when exposed to a high-temperature atmosphere, and can be used even when the pressure-sensitive adhesive tape is peeled off from the adherend. There is no occurrence of adhesive residue due to cohesive failure of the pressure-sensitive adhesive layer. Further, even when the adhesive tape is formed into a wound body, the unwinding force of the adhesive tape is at an appropriate level, and the unwinding of the adhesive tape from the wound body can be performed smoothly. On the other hand, the pressure-sensitive adhesive tape of Comparative Example 1 has a problem that the unwinding force of the pressure-sensitive adhesive tape is too high because the back surface treatment layer does not contain the long-chain alkylethylene urea. Further, since the pressure-sensitive adhesive tape of Comparative Example 2 does not contain a functional monomer in the copolymer serving as the main component of the pressure-sensitive adhesive, the self-back surface adhesive force is low, and the pressure-sensitive adhesive layer causes cohesive failure. There's a problem. Furthermore, the pressure-sensitive adhesive tape of Comparative Example 3 has a problem that the pressure-sensitive adhesive layer undergoes cohesive failure because the copolymer serving as the main component of the pressure-sensitive adhesive is not adjusted by emulsion polymerization.

[0045]

The pressure-sensitive adhesive tape of the present invention has the following effects by having the above configuration. (1) Even when exposed to a high-temperature atmosphere in a state where the adhesive tapes are stacked and adhered, the adhesive tapes do not float or peel in the overlapped area. (2) When the adhesive tape is peeled off from the adherend after being exposed to a high-temperature atmosphere in a state where the adhesive tape is adhered to the adherend, the adhesive layer causes cohesive failure and the adhesive residue is removed. Does not occur. (3) When the pressure-sensitive adhesive tape is a wound body, the rewinding property when the pressure-sensitive adhesive tape is rewound from the wound body can be made smooth. Therefore, the pressure-sensitive adhesive tape of the present invention is used, for example, when the pressure-sensitive adhesive tapes are overlapped and used like a masking pressure-sensitive adhesive tape used in a coating process of an automobile body,
Even when put in a high-temperature atmosphere such as a drying step in the state of being overlapped and pasted, there is no occurrence of peeling or floating in the overlapped area, and during the drying step of the paint, the undried paint from the overlapped area is removed. The coating does not invade and causes poor coating, and the reliability of the masking function can be improved. In addition, even when the adhesive tape is peeled off after the drying step, the adhesive tape can be smoothly peeled without leaving the adhesive on the adherend surface, so that the work efficiency of the masking work in the painting step is improved. Can be. Further, since the pressure-sensitive adhesive tape roll of the present invention has an appropriate rewinding property, it is excellent in workability when the pressure-sensitive adhesive tape is rewound from the roll and attached to the adherend, and the workability is improved. Can be improved.

Claims (3)

[Claims] 1. A pressure-sensitive adhesive tape in which a back treatment layer is formed on one side of a base material and an adhesive layer is formed on the other side, wherein the back treatment layer contains a long-chain alkylethylene urea as an essential component, The main component of the adhesive constituting the adhesive layer is
A copolymer obtained by copolymerizing a monomer mixture containing an alkyl (meth) acrylate having an average of 4 to 12 carbon atoms in an alkyl group and a functional monomer copolymerizable therewith by emulsion polymerization. An adhesive tape, characterized in that: 2. A functional monomer copolymerizable with an alkyl (meth) acrylate is selected from carboxyl, hydroxyl, epoxy, amino, mercapto and isocyanate groups in the molecule. The pressure-sensitive adhesive tape according to claim 1, comprising a monomer having at least one functional group. 3. The pressure-sensitive adhesive tape according to claim 1, which is used for masking.