JP2000265125A - Adhesive tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an adhesive tape having a sufficiently high binding performance and useful e.g. as a substitute for conventional binding tape having PVC substrate by using a specific acrylic resin as the component and setting the rewinding force to a specific level. SOLUTION: The objective adhesive tape has a polyolefin film as the substrate and an adhesive layer formed on a surface of the substrate. The adhesive layer is composed of an acrylic resin containing 40-99 wt.%, preferably 80-99 wt.% acrylic acid ester monomer having a >=8C alkyl group such as 2-ethylhexyl acrylate and the tape has a rewinding force of 400-2,000 gf/19 mm at a rewinding speed of 30 m/min. The acrylic resin may contain acrylic acid, butyl acrylate, etc., as a constituent component other than the above ester monomer and further contain an additive such as a crosslinking agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an adhesive tape. More specifically, the present invention relates to a pressure-sensitive adhesive tape in which the support is a polyolefin film, the pressure-sensitive adhesive layer contains a long-chain acrylate ester, and can be used as a binding tape having a specific unwinding force.

[0002]

2. Description of the Related Art A conventional adhesive tape used as a binding tape has a feature that a binding portion is sequentially fixed by an adhesive, and a terminal portion is also fixed by an adhesive. Furthermore, after the binding material is fixed by the advantage of the adhesive, when the binding material is released, the binding material is easily opened due to the removability, which is an advantage of adhesiveness, and these properties are often used as a binding tape. In these applications, if flexibility is required, polyvinyl chloride (hereinafter, referred to as PVC) or polyethylene (hereinafter, PE)
) And polypropylene (hereinafter referred to as PP) such as a polyolefin film as a support are often used.

However, due to recent environmental problems, PV
Replacements of C-support tapes have been desired because they require special management for disposal after use. Alternatives include:
From the viewpoints of both cost and flexibility, tapes using a polyolefin film such as PE and PP as a support have been studied. However, these tapes have a disadvantage that it is difficult to obtain a tape having good binding properties.

When a polyolefin film is used as a support, rubber and acrylic pressure-sensitive adhesives are used in terms of cost. However, when a rubber-based pressure-sensitive adhesive is used, the adhesive strength to the polyolefin film is so strong that the film cannot be rewound. As a countermeasure, it is suggested to design the adhesive strength of the pressure-sensitive adhesive to be low or to apply a back surface treatment agent to facilitate the peeling. However, in the former method, the adhesive strength to the adherend to be bound cannot be satisfied, and in the latter method, the fixing force required for binding at the terminal cannot be obtained, and both are unsatisfactory as substitutes. Also,
Acrylic pressure-sensitive adhesives have poor adhesion to polyolefin films, and therefore have the drawback that the unwinding force required for bundling cannot be obtained.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an adhesive tape which can be used as a substitute for a binding tape of a conventional PVC support.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems. As a result, the support was a polyolefin film, and the pressure-sensitive adhesive layer was an acrylic acid having an alkyl group having 8 or more carbon atoms. The present inventors have found that an adhesive tape made of an acrylic resin containing a specific amount of an ester monomer and having a specific unwinding force has a sufficient binding property, and the present invention has been completed.

That is, the present invention provides (1) a tape having a polyolefin film as a support and having an adhesive layer on one surface of the support, wherein the adhesive layer has an alkyl group having 8 or more carbon atoms. Is an acrylate monomer of 40 to
It is made of acrylic resin containing 99% by weight and has a rewinding force of 400 gf / 19 mm at a rewinding speed of 30 m / min.
(2) a pressure-sensitive adhesive tape according to the above (1), wherein the pressure-sensitive adhesive tape contains 80 to 99% by weight of an acrylate monomer having an alkyl group carbon number of 8 or more. And (3) the adhesive tape according to the above (1) or (2) for binding.

[0008] A polyolefin film is a support,
Conventional adhesive tapes in which the adhesive is an acrylic resin have poor adhesion of the acrylic resin to the polyolefin film. In contrast, in the present invention, the compatibility between the acrylic resin and the polyolefin is improved by increasing the amount of the alkyl group relative to the polyolefin, that is, by using a long-chain acrylate having an alkyl group carbon number of 8 or more. It can be presumed that the adhesion increased and the adhesion improved.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The constituent components of the support used in the present invention are not particularly limited as long as they are polyolefins. Polyethylene, polypropylene, polybutene, polybutylene,
Examples thereof include a methylpentene resin and polybutadiene, and preferably include polyethylene and polypropylene. One or more of these components may be used.

The thickness of the support of the present invention is 20 to 300 μm.
m, and preferably 50 to 150 μm.

The support of the present invention may further contain additives, for example, calcium carbonate, titanium oxide,
Fillers such as silicon oxide, aluminum hydroxide, magnesium hydroxide, chlorine-based, bromine-based flame retardants, coloring agents,
Lubricants and anti-aging agents.

The molding of the support is not particularly limited, and can be performed by a known method. For example, when the melt flow rate (index according to JIS K 6760, hereinafter referred to as MFR), which is an index of the melt viscosity of the resin used for the support, is large, extrusion molding by a T-die is used. To do. Further, calender molding is preferable in a resin system having a large amount of rubber and a compound system having a large amount of a filler.

The surface of the obtained support in contact with the pressure-sensitive adhesive may be subjected, if necessary, to a treatment for increasing the adhesiveness between the pressure-sensitive adhesive layer and the support. For example, a method of giving irregularities to the pressure-sensitive adhesive surface utilizing the difference in surface properties of both surfaces of the support, a method of treating the adhesive surface with corona discharge to make the wettability to adhesion different, and a known anchor coating agent To the boundary between the pressure-sensitive adhesive and the support. The treatment for improving the adhesion in the present invention is not limited to these, and may be used sequentially as necessary.

The pressure-sensitive adhesive layer of the present invention comprises an acrylic resin containing a specific amount of an acrylate monomer having an alkyl group carbon number of 8 or more. The acrylate monomer having an alkyl group carbon number of 8 or more contains 4
0 to 99% by weight, preferably 80 to 99% by weight, and when the acrylate monomer having an alkyl group carbon number of 8 or more is contained in less than 40% by weight, the adhesiveness is poor and the binding property is low. Become.

The acrylate monomer having an alkyl group having 8 or more carbon atoms in the present invention includes 2-ethylhexyl acrylate, octyl acrylate, lauryl acrylate, and the like.
-Ethylhexyl acrylate. One or more of these monomers may be used.

The constituents other than the acrylate monomer having 8 or more alkyl carbon atoms contained in the pressure-sensitive adhesive layer of the present invention include acrylic acid, methacrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, and butyl acrylate. , Isobutyl acrylate, tert-butyl acrylate, hexyl acrylate and the like, and preferably acrylic acid and butyl acrylate. One or more of these monomers may be used.

The pressure-sensitive adhesive layer of the present invention may further contain an additive. Examples of the additive include a tackifier such as a crosslinking agent, a colorant, a flame retardant, a xylene resin, and a rosin resin.

The acrylic resin as the pressure-sensitive adhesive layer of the present invention comprises:
The polymerization may be performed by a usual method, and examples of the polymerization method include radical polymerization, cationic polymerization, and anionic polymerization, and preferably include radical polymerization. Additives used in these polymerizations may be those usually used, for example, as a polymerization initiator when performing radical polymerization, organic peroxides such as benzoyl peroxide and tert-butyl hydroperoxide, and azobisisobutyro. An azo compound such as nitrile is exemplified.

The pressure-sensitive adhesive tape of the present invention is preferably provided, for example, on a support formed by any of the above-described methods to enhance the adhesiveness of the pressure-sensitive adhesive layer to the surface in contact with the pressure-sensitive adhesive layer, if necessary. It is obtained by applying a pressure-sensitive adhesive layer after performing the treatment. The pressure-sensitive adhesive layer has a thickness of 5 to 1 after drying.
It is applied to a support so as to have a thickness of 00 μm, preferably 10 to 50 μm.

The rewinding force of the pressure-sensitive adhesive tape in the present invention is 400 gf / 19 mm at a rewinding speed of 30 m / min.
2000 gf / 19 mm, preferably 500 gf
/ 19 mm to 2000 gf / 19 mm, and the adhesive tape of the present invention has good binding properties.

The pressure-sensitive adhesive tape of the present invention can also be used as a substitute for a binding tape of a PVC support, for example, for sealing a lid such as a can, for binding a wire or the like.
It can be used for bundling tubular objects such as VC pipes and foam pipes for heat insulation.

[0022]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples. Abbreviations described in Examples and Comparative Examples have the following meanings. AA: acrylic acid, BA: butyl acrylate, and 2EHA: 2-ethylhexyl acrylate.

Example 1 Low density polyethylene (manufactured by Mitsubishi Kasei Corporation, trade name: Mitsubishi Polyethylene LD F-131, density 0.924 g / cm ³ , M
FR 1.3 g / 10 min) into a film having a thickness of 100 μm by a usual inflation method. Perform corona discharge in advance on the surface of the obtained film to which the adhesive layer is applied,
The surface tension was adjusted to 42 dyne / cm. The obtained polyethylene film was used as a support. A peroxide nipper BO (manufactured by NOF Corporation) was added as a polymerization initiator to 100 parts by weight of a mixture composed of 5% by weight of AA (manufactured by Toa Gosei) and 95% by weight of 2EHA (manufactured by Toa Gosei). 0
3 parts by weight, and toluene as a solvent having a mixture concentration of 3
It was added so as to be 0% by weight, and radical polymerization was performed at a time to obtain an acrylic polymer.

0.03 parts by weight of an epoxy-based crosslinking agent Tetrad C (manufactured by Mitsubishi Gas Chemical Co.) is blended with 100 parts by weight of the obtained polymer in a dry weight, and the thickness after drying is 30 parts.
It was applied by a known method (drying temperature: 100 ° C., drying time: 5 minutes) to a thickness of μm and wound around a 75φ paper tube to obtain a raw tape. The obtained raw tape was cut into a width of 19 mm to prepare a binding tape.

Example 2 An acrylic polymer was obtained and a tape was prepared in exactly the same manner as in Example 1 except that AA 5% by weight and 2EHA 95% by weight were changed to AA 5% by weight, BA 55% by weight and 2EHA 40% by weight. .

Example 3 An acrylic polymer was obtained and a tape was prepared in exactly the same manner as in Example 1 except that 5% by weight of AA and 95% by weight of 2EHA were changed to 5% by weight of AA, 15% by weight of BA and 80% by weight of 2EHA. .

Comparative Example 1 An acrylic polymer was obtained and a tape was prepared in exactly the same manner as in Example 1 except that AA 5% by weight and 2EHA 95% by weight were changed to AA 5% by weight and BA 95% by weight.

Comparative Example 2 An acrylic polymer was obtained and a tape was prepared in exactly the same manner as in Example 1 except that AA 5% by weight and 2EHA 95% by weight were changed to AA 5% by weight, BA 65% by weight and 2EHA 30% by weight. .

The pressure-sensitive adhesive tapes obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were measured for a rewind force,
Evaluation of cohesion was performed as follows.

[0030]

[Experimental example] Measurement of unwinding force According to JIS Z 0237, the tape was unwound at a rewinding speed of 30 m / min. Table 1 shows the obtained results.

Evaluation of binding property Five PVC pipes having a diameter of 30φ were bound with an adhesive tape in three turns. After the end of the tape was cut, the terminal was held down by hand and adhered. The ease with which the windings were tightened when tied with an adhesive tape was evaluated subjectively and classified as follows. ：: Sufficient binding is obtained from the rewinding force. Δ: Bundling is possible by applying a slight force to the unwinding force. X: The binding property was not obtained even if a slight force was applied to the rewinding force. Table 1 shows the obtained results.

[0032]

[Table 1]

[0033]

According to the present invention, it is possible to provide a pressure-sensitive adhesive tape having good binding properties. For example, it is possible to provide an alternative to the conventional binding tape in which PVC is a support.
The pressure-sensitive adhesive tape of the present invention can be used, for example, for sealing lids such as cans, for binding electric wires, and for binding tubular materials such as PVC pipes and foamed pipes for heat insulation.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kazuhito Goto 1-2-1 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation F-term (reference) 4J004 AA10 AB01 CA04 CC02 FA06 FA08

Claims (3)

[Claims] 1. A tape having a polyolefin film as a support and an adhesive layer on one surface of the support, wherein the adhesive layer comprises an acrylate monomer having an alkyl group carbon number of 8 or more. It is made of an acrylic resin containing 40 to 99% by weight and has a rewinding force of 400 gf / 19 mm to 2000 gf / 1 at a rewinding speed of 30 m / min.
An adhesive tape having a size of 9 mm. 2. The pressure-sensitive adhesive tape according to claim 1, wherein the pressure-sensitive adhesive tape contains 80 to 99% by weight of an acrylate monomer having an alkyl group having 8 or more carbon atoms. 3. The pressure-sensitive adhesive tape according to claim 1, which is used for binding.