JPH05247413A - Sealing member - Google Patents

Abstract

PURPOSE:To obtain a sealing member which can be peeled off from, e.g. a case made of paper without damaging it and enables the reuse of the case. CONSTITUTION:A sealing member having an adhesive layer 3 which contains a foaming agent and whose adhesive force decreases at least on one side of a porous sealant base material 1, if necessary, with an intermediate layer film 2 lying therebetween. Since the adhesive layer contains a foaming agent and its adhesive force decreases or vanishes by heat treatment, this member can be smoothly peeled off at an excellent working efficiency and enables the reuse of an adherend such as a case.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention contains a foaming agent to reduce the adhesive strength by heat treatment, and enables peeling without damaging the paper case or the like, enabling reuse of the paper case or the like. The present invention relates to a sealed member.

[0002]

2. Description of the Related Art Heretofore, there has been known a sealing member formed by laminating a double-sided adhesive tape on a porous sealing substrate made of felt or foam. It is used as a seal tape for a paper case such as a toner case.

However, there is a problem that the adhesive strength is so great that it is damaged when peeled from the paper case, and the paper case cannot be reused. Further, it is difficult to directly apply the pressure-sensitive adhesive to the porous seal substrate, and the double-sided pressure-sensitive adhesive tape is laminated with the porous seal substrate. However, there is a problem in that the production of the seal member requires many steps.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to obtain a seal member that can be peeled off from a paper case or the like without damaging it and the case can be reused.

[0005]

The present invention is characterized in that an adhesive strength-reducing adhesive layer containing a foaming agent is provided on at least one side of a porous seal substrate, if necessary with a film-like intermediate layer interposed therebetween. A seal member is provided.

[0006]

By the treatment for reducing the adhesive force by heating the adhesive force reducing type adhesive layer, the foaming agent contained therein expands or foams, whereby the adhesive force decreases or disappears. As a result, it can be peeled off easily from the adherend such as a case, and even in the case of a paper case, it can be reused without damaging it.

[0007]

EXAMPLE FIG. 1 illustrates the seal member of the present invention. Reference numeral 1 is a porous seal base material, and 3 is a foaming agent-containing adhesive strength reduction type adhesive layer. In addition, 2 is a film-shaped intermediate | middle layer provided as needed.

As the porous sealing base material, an appropriate porous structure having a sealing ability capable of preventing the liquid from flowing out or the like depending on the intended sealing target such as liquid or powder, for example, felt or foam is used. Be done. The thickness is generally 5 mm or less from the viewpoint of flexibility and the like, and particularly 0.1 to 1 mm, but the thickness is not limited to this.

An appropriate adhesive can be used to form the adhesive force reduction type adhesive layer, and a pressure sensitive adhesive or the like is generally used. As the pressure-sensitive adhesive, an appropriate material such as a rubber-based pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive, a styrene / conjugated diene block copolymer-based pressure-sensitive adhesive can be used. Etc. can be used (JP-A-56-61468, JP-A-61-174857, JP-A-63-17981).

In addition, those having a melting point of about 200 ° C. or less to improve the creep property, and those which have a low adhesive strength at room temperature and exhibit sufficient adhesive strength by heating. A pressure sensitive adhesive or the like can also be used (Japanese Patent Publication No. 56-
13040). The pressure-sensitive adhesive may be a mixture of appropriate additives such as a cross-linking agent, a tackifying resin, a plasticizer, a filler, and an anti-aging agent, if necessary.

More specifically, for example, a rubber-based pressure-sensitive adhesive containing natural rubber or synthetic rubber as a base polymer, methyl group, ethyl group, propyl group, butyl group, 2-ethylhexyl group, isooctyl group, isononyl group, Usually, such as isodecyl group, dodecyl group, lauryl group, tridecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group and eicosyl group, such as acrylic acid or methacrylic acid having an alkyl group having 20 or less carbon atoms, Acrylic acid alkyl ester, acrylic acid, methacrylic acid, itaconic acid, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate,
Acrylic pressure-sensitive adhesive based on an acrylic polymer containing N-methylolacrylamide, acrylonitrile, methacrylonitrile, glycidyl acrylate, glycidyl methacrylate, vinyl acetate, styrene, isoprene, butadiene, isobutylene, vinyl ether, etc. Etc.

It is preferable in terms of the balance between the adhesive force before the adhesive force reduction process and the adhesive force reduction property due to the adhesive force reduction process, and the adhesion followability with the adherend when it is used as a rolled material or during bending. The pressure-sensitive adhesive that can be used has a dynamic elastic modulus of 500,000 to 10,000,000 dyne / cm at room temperature to 150 ° C.
² , preferably a highly elastic polymer in the range of 500,000 to 8,000,000 dyne / cm ² as a base polymer. Highly elastic polymers that are more preferable as the base polymer are those having a small change rate of the dynamic elastic modulus from room temperature to 150 ° C., and in particular, those having a change degree of 5 times or less.

The adhesive strength reduction type adhesive layer can be formed by blending an adhesive with a foaming agent. By blending the foaming agent, it is possible to form an adhesive layer in which the adhesive strength is reduced or disappears due to expansion or foaming of the contained foaming agent by heat treatment. When the pressure sensitive adhesive at the time of heat is used, a foaming agent that expands or foams at a temperature higher than the bonding treatment temperature of the adhesive is used.

The blending amount of the foaming agent may be appropriately determined depending on the degree to which the adhesive force is reduced. Generally, 1 to 100 parts by weight, preferably 5 to 50 parts by weight, especially 10 to 40 parts by weight are blended per 100 parts by weight of the base polymer.

The blowing agent used is not particularly limited,
Various inorganic or organic foaming agents can be used. As typical examples of the inorganic foaming agent, ammonium carbonate, ammonium hydrogen carbonate, sodium hydrogen carbonate, ammonium nitrite,
Examples thereof include sodium borohydride and azides.

Typical examples of organic blowing agents include water, fluorinated alkanes such as trichloromonofluoromethane and dichloromonofluoromethane, and azo compounds such as azobisisobutyronitrile, azodicarbonamide and barium azodicarboxylate. Compounds, hydrazine compounds such as paratoluenesulfonyl hydrazide, diphenylsulfone-3,3′-disulfonylhydrazide, 4,4′-oxybis (benzenesulfonylhydrazide) and allylbis (sulfonylhydrazide), ρ-toluylenesulfonyl semicarbazide and Semicarbazide compounds such as 4,4′-oxybis (benzenesulfonyl semicarbazide), triazole compounds such as 5-morpholyl-1,2,3,4-thiatriazole, N, N′-dinitrosopentamethylenetetrami And N, N'-dimethyl -
Examples thereof include N-nitroso compounds such as N, N'-dinitrosoterephthalamide.

The heat-expandable fine particles obtained by encapsulating the foaming agent in microcapsules are preferably used because the mixing operation is easy. As the heat-expandable fine particles, there are commercially available products such as Microsphere (trade name, manufactured by Matsumoto Yushi Co., Ltd.). In the present invention, a foaming aid may be added if necessary.

The sealing member may be formed by an appropriate method such as a method of transferring the foaming agent-containing adhesive strength-reducing adhesive layer coated on the separator to at least one side of the porous seal substrate. it can. When a film-shaped intermediate layer is provided on the surface of the porous seal substrate on which the adhesive layer is attached by an appropriate method such as an extrusion film forming method or a film laminating method, the adhesive layer is formed by a direct adhesive coating method. You can
Excellent manufacturing efficiency. The thickness of the adhesive strength reduction type adhesive layer to be provided may be appropriately determined. Generally, the thickness is 500 μm or less, especially 5 to 200 μm.

Further, the provision of the film-like intermediate layer is effective for forming an adhesive layer having excellent surface smoothness, and is advantageous for improving the stability of the bonding work and preventing the dispersion. The film-like intermediate layer can be formed of various polymers or metal foils, and the thickness is generally 5 to 500 μm, but the thickness is not limited to this. When the adhesive force reduction type adhesive layer is provided on one side of the porous seal substrate, an adhesive layer having a pressure sensitive property which is not the adhesive force reduce type adhesive layer may be provided on the other side.

The reduction or elimination of the adhesive force of the adhesive force reducing type adhesive layer in the seal member (adhesive force reducing treatment) is as follows.
It can be performed by expanding or foaming the foaming agent in the adhesive layer by heating. The heating conditions may be appropriately determined depending on the foaming characteristics of the foaming agent, the heat resistance of the base material used for the seal member, and the like. The heat treatment may be performed at an appropriate stage depending on the purpose of use.

The seal member of the present invention is required to be easily peeled off from the adherend after being adhered to the adherend and after the purpose of sticking is completed, or when the contents are replaced or replenished. Can be preferably used for Examples thereof include a sealing treatment of a toner case, a chemical bottle, and the like, which can be preferably used particularly for a paper product or the like which is easily damaged when the seal member is peeled off.

Example 1 100 parts of a base polymer having a weight average molecular weight of 1.2 million and consisting of a copolymer of 100 parts of butyl acrylate (parts by weight, the same applies hereinafter), 5 parts of acrylic acid and 10 parts of acrylonitrile, and heat-expandable fine particles (micro) Sphere F-80SD)
A toluene solution of an adhesive containing 15 parts is applied to one side of the separator and dried to form a 30 μm-thick adhesive strength-reducing adhesive layer, which is applied to one side of a 50 μm-thick nylon felt. To obtain a seal member.

Example 2 Pressure-sensitive adhesive 1 containing acrylic graft rubber as a main polymer and 30 parts of a terpene-based tackifying resin (Tg 120 ° C.)
On a 25 μm-thick polyester film layer obtained by laminating 50 parts of heat-expandable fine particles (Microsphere F-80SD) in a toluene solution containing 00 parts on one side of a nylon felt having a thickness of 50 μm. Was applied to the above and dried to form a 30 μm thick adhesive strength-reducing type adhesive layer to obtain a seal member.

Comparative Example 1 A sealing member was obtained in the same manner as in Example 1 except that an adhesive containing no heat-expandable fine particles was used.

Comparative Example 2 A sealing member was obtained in the same manner as in Example 2 except that an adhesive containing no heat-expandable fine particles was used.

Evaluation Test Adhesive Strength A stainless steel plate (SUS 304 B) was used for the (adhesive strength reduction type) adhesive layers in the seal members obtained in Examples and Comparative Examples.
Adhesive strength (180 degree peel) after room temperature (adhesive treatment) or heat treatment (adhesive strength reduction treatment) at 150 ° C. for 1 minute with respect to A finished surface) was measured according to JIS Z 0237.

Peelability Using the sealing members obtained in Examples and Comparative Examples, the lid of the cardboard box was subjected to seal adhesion treatment according to the above, followed by heat treatment (adhesion reduction treatment), and then the seal member was peeled and peeled. The sex was evaluated. The evaluation criteria were as follows: ○ when the paper forming the cardboard box was broken and peeled without damage, and × when the paper forming the cardboard box was broken or damaged during peeling.

The above results are shown in Table 1.

[Table 1]

[0029]

According to the present invention, it is possible to obtain a seal member whose adhesive layer contains a foaming agent and whose adhesive strength is reduced or eliminated by heat treatment, and which is easily adhered to paper or foam. In the case of a body, it can be peeled off smoothly without damaging it, and the work efficiency is excellent, and the adherend such as a case can be reused.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment.

[Explanation of symbols]

 1: Porous seal substrate 2: Film-like intermediate layer 3: Foaming agent-containing adhesive strength reduction type adhesive layer

Claims (2)

[Claims] 1. A sealing member comprising a porous seal substrate and a foaming agent-containing adhesive strength-reducing adhesive layer on at least one side of the porous seal substrate. 2. The seal member according to claim 1, further comprising a film-like intermediate layer between the porous seal substrate and the adhesive force reduction type adhesive layer.