JPH04198976A - Method for peeling label of bottle - Google Patents

Abstract

PURPOSE:To allow the easy peeling of a label from a bottle after use of the bottle by previously irradiating the label with active energy rays to crosslink and cure an active ray curing tacky adhesive to lower the adhesive power of an active ray curing tacky adhesive layer, then stripping the label. CONSTITUTION:The active ray curing tacky adhesive is applied on the surface of an active energy ray transmittable base material, by which the active ray curing tacky adhesive layer is provided and the active ray curing tacky adhesive sheet is obtd. After suitable required items are printed on this active ray curing tacky adhesive sheet, the sheet is cut to a desired size to prepare the label. This label is used as the tacky active label and is stuck to various kinds of the bottles. The active ray curing tacky adhesive provided on the surface of the base material crosslink and cure and the tacky adhesive power thereof decreases if this tacky active label is irradiated with the active energy rays. The label is easily stripped from the bottle in this way.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for removing labels from bottles.

In particular, by applying an adhesive label using an active energy ray-curable adhesive, the label can be easily peeled off after the bottle is used.

[Conventional technology]

BACKGROUND OF THE INVENTION After use, glass bottles used for beer, Western liquor, sake, cider, cola and other soft drinks are collected and returned to the manufacturer for repeated use.

Normally, these bottles have a label printed with the type, product name, origin, and other necessary information related to the contents. - On boat fishing, labels are affixed to bottles with water-soluble glue or adhesive, such as starch. After use, when the collected bottles are to be used repeatedly, the labels affixed to the bottles must be peeled off from the bottles and processed in a bottle washing process. In the bottle washing process, an aqueous solution of caustic soda with a concentration of 3 to 5% is used.
It is common to undergo harsh treatment at temperatures of around 70°C. As a result, the label can be peeled off from the bottle, but with paper-based labels, the harsh treatment with warm alkali causes the paper layer to collapse, causing problems in wastewater treatment. I'm leaving it behind.

The labels affixed to bottles are affixed to the bottles taking the above points into consideration, and are firmly adhered so that they do not peel off from the bottles until they reach the consumers through the distribution process. On the other hand, in the bottle washing process where labels are washed off from bottles for repeated use of collected bottles, it is desired that the labels be easily peeled off from the bottles, and labels are required to have conflicting suitability before and after use. ing.

[Problem to be solved by the invention]

For this reason, various improvements have been made to labels in the past, including the water resistance of label paper and adhesives, but the reality is that nothing satisfactory has yet been achieved.

[Means to solve the problem]

The inventors of the present invention have made intensive studies to solve these conventional drawbacks, and as a result, have succeeded in solving the problems without requiring an alkali treatment step, and have completed the present invention.

That is, the present invention provides a label peeling method for a bottle having an adhesive label affixed thereto, which is formed by applying an active energy ray curable adhesive to the surface of an active energy ray transparent base material to provide an active energy ray curable adhesive layer. In the method, after the bottle is used, the label is irradiated with active energy rays in advance to crosslink and cure the active energy ray-curable adhesive to reduce the adhesive strength of the active energy ray-curable adhesive layer, and then the label is peeled off. This is a method for removing labels from bottles.

[Operation and mode of the invention]

The active energy ray-transparent base material constituting the adhesive label used in the present invention is one that transmits active energy rays such as ultraviolet rays and electron beams, such as polyester, polyethylene, polypropylene, polycarbonate, polyvinyl chloride, acetate, etc. Single layer films, composite films, etc. can be used. These films are of suitable thickness to be used as bottle labels and are
Preferably, it has a diameter of 20 to 200μ.

An active energy ray curable adhesive is applied to the surface of these active energy ray transparent substrates to provide an active energy ray curable adhesive layer, thereby obtaining an active energy ray curable adhesive sheet.

In the present invention, the active energy ray-curable pressure-sensitive adhesive sheet thus obtained is prepared by appropriately printing necessary information and then cut into a desired size, used as a pressure-sensitive adhesive label, and pasted on various bottles.

An active energy ray-curable adhesive is applied to the surface of an active energy ray-transparent substrate, and in the case of an active energy ray-curable adhesive layer, the adhesive strength is increased to prevent the label from peeling off from the bottle. 200~2000gr/25m
It has a width of m and has a fairly strong adhesive force. When irradiated with active energy rays, it crosslinks and hardens, increasing the adhesive strength to 2 to 2.
It has a characteristic that the width decreases to 0gr/25mm width. As an adhesive having such characteristics, a photoreactive adhesive obtained by blending 10 to 200% of a photoreactive prepolymer and/or a photoreactive monomer with a normal acrylic adhesive can be used.

Examples of acrylic adhesives include those whose main components are polymers of acrylic esters having 2 to 8 carbon atoms and copolymers with vinyl monomers such as vinyl acetate, vinylidene chloride, and methacrylic esters. I can do it. The photoreactive prepolymers blended into the acrylic adhesive include polyester monoacrylate, polyester diacrylate, polyester triacrylate,
These include epoxy acrylate, polyurethane acrylate, polyether acrylate, melamine acrylate, alkyd acrylate, and silicone acrylate. Specific examples include isodecyl acrylate, stearyl acrylate-1-, lauryl acrylate, benzyl acrylate, allyl acrylate, 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, polyethylene glycol diacrylate, etc. I can do it. Further, the photoreactive monomers are as follows.

Monofunctional monomers 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, tetrahydrofurfuryl acrylate, etc. Difunctional monomers dicyclopentenyl acrylate-1-, 1,3-butanediol diacrylate, 1. 4-Butanediol diacrylate, polyethylene glycol diacrylate, etc. Trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, etc. Among these, polyester acrylates mainly containing ester bonds Compared to other acrylic oligomers such as epoxy acrylates and urethane acrylates, it is easy to obtain liquids with relatively low viscosity, exhibits excellent reactivity, and is highly compatible with other polymers and oligomers. Especially suitable because it is good.

It is more effective to add a crosslinking agent to the active energy ray curable adhesive, and further add an exacerbating agent to improve the active energy ray curing reaction. Examples of crosslinking agents include peroxides, polyisocyanates, phosphoric acids, metal salts, and the like. In addition, the sensitizers include benzoin, hendiine ethyl ether, pentuine isopropyl ether, diphenyl sulfide, anthracene, benzophenone, α-chloroanthraquinone, diphenyl sulfide, diacetyl, hexachlorobutadiene, pentachlorophtadiene, octachlorobutene,
Examples include 1-chloromethylnaphthalene, and 0
．． Normally, the effect is sufficiently exerted at 3% or less.

The active energy ray-curable adhesive of the present invention has such a component composition, and is prepared by preparing an adhesive coating using an organic solvent and applying it to an active energy ray-transparent substrate by a conventional method to absorb active energy. By providing a radiation-curable adhesive layer, an active energy radiation-curable adhesive sheet can be obtained. As the organic solvent, toluene, ethyl acetate, methyl ethyl ketone, acetone, etc. can be used. and,
The active energy ray-curable adhesive layer is protected, if necessary, with a release sheet commonly used for adhesive sheets.

In this case, if the non-adhesive layer surface of the active energy ray transparent substrate is treated with a release backing agent in advance, the active energy ray curable adhesive paint can be applied and then rolled up without using a release sheet. It is possible to omit a release sheet.

The adhesive label used in the present invention is produced by printing desired items on the surface of the base material using the active energy ray-curable adhesive sheet obtained in this way, and subjecting the surface to a primer treatment if necessary, or applying a surface coat sheet to an appropriate size. Manufactured by cutting into pieces. The adhesive label is then applied to the bottle using an automatic tag applicator or the like.

When the adhesive label of the present invention attached to a bottle is irradiated with active energy rays, the active energy ray-curable adhesive provided on the surface of the base material is crosslinked and cured, reducing its adhesive strength. Then, it can be easily peeled off from the bottle. As active energy rays, actinic rays such as ultraviolet rays and other ionizing radiations such as stimulant rays and gamma rays can be applied.By irradiation, the active energy ray-curable adhesive is cross-linked and cured, increasing its adhesive strength. It is possible to lower the temperature and peel off adhesive labels attached to bottles.

The ultraviolet light used in the ultraviolet irradiation of the present invention is about 2
In the wavelength range of 00 to 400 nm, a mercury arc, low pressure, medium pressure, high pressure mercury lamp, carbonate arc, etc. can be used as the ultraviolet light source. As for the irradiation time of ultraviolet rays, 0.1 to 10 seconds is sufficient. If the irradiation amount is weaker than this, crosslinking and curing of the adhesive will not proceed, making it difficult to remove the label.

In addition, for electron beam irradiation, which is a typical type of ionizing radiation, the accelerating voltage is 100 to 1500 K in terms of penetrating power and curing power.
v, preferably using an electron beam accelerator of 100 to 500 Kv, and the absorbed dose in one pass is 0.2 to 5 Mrad.
If it is lower than this range, crosslinking and curing of the adhesive will not proceed, making it difficult to remove the label.

〔Example〕

Further, the present invention will be explained by examples.

Example 1 Compounding composition Part by weight Acrylic adhesive 100 (SK die manufactured by Soken Chemical Co., Ltd.: /
5W-2B) Polyester prepolymer 30
(NKS-1 manufactured by Dainichiseika Chemicals) Benzophenone Trifunctional polyisocyanate 6 (Coronet manufactured by Nippon Polyurethane) L) Toluene 20
Ethyl acetate 20 Prepare a UV-curable adhesive paint with the above composition and apply it to a 25μ thick polyester film at a coating amount of 20 gr/m” (solid content) to form a UV-curable adhesive layer. A UV-curable adhesive sheet was obtained by laminating silicon release paper.A test piece of 10 cm long x 25 mm wide was made from this UV-curable adhesive sheet for use as an adhesive label.
The release paper was peeled off and it was attached to a glass plate, and the adhesive strength from the glass plate was measured 24 hours later. Its adhesive strength is 470
gr/25mm width.

Similarly, after 24 hours, a conveyor-type ultraviolet irradiation device (metal halide lamp manufactured by Ushio Inc., 8Qw/cm, main wavelength 320 nm) was applied from the polyester film side.
The adhesive force was measured after cross-linking and curing the ultraviolet curable adhesive by irradiating it for about 3 seconds at a distance of IQ cm. The adhesive strength was 6 gr/25+nm width, which could be reduced by UV irradiation, and the test piece could be peeled off from the glass plate very easily. After removing the test piece, no adhesive residue was found on the glass plate.

Example 2 Compounding composition Part by weight Acrylic adhesive 100 (SK Tine 5 manufactured by Soken Chemical Co., Ltd.
W-2B> Polyester prepolymer 50 (N made by Dainichiseika Chemical Co., Ltd.
KS-5> Benzophenone 3 Epoxy crosslinking agent 10 (Soken Chemical E-AX) Toluene 20 Ethyl acetate
20 Prepare an ultraviolet curable adhesive paint having the above composition and apply it to a 50μ thick polyester film at a coating amount of 25 gr/m'' (solid content) to form an ultraviolet curable adhesive layer, A UV-curable adhesive sheet was obtained by laminating silicone release paper.From this UV-curable adhesive sheet, 1OCII was used for adhesive labels.
A test piece of 1 length x 25 mm width was prepared, the release paper was peeled off and it was attached to a glass plate, and the adhesive force from the glass plate was measured 24 hours later. Its adhesive strength is 200 gr/2
It was 5a+m wide.

Similarly, after 24 hours, a conveyor-type ultraviolet irradiation device (metal halide lamp 8Q w/(z dominant wavelength 320
After cross-linking and curing the ultraviolet curable adhesive, the adhesive strength was measured by irradiating the adhesive at a distance of 10 cm for about 3 seconds.

The adhesive strength was 5 gr/25 mm width, and the adhesive strength could be reduced by UV irradiation, and the test piece could be peeled off from the glass plate very easily. After peeling off, no adhesive residue was found on the glass plate.

Example 3 Compounding composition Part by weight Acrylic adhesive 100 (SK tie manufactured by Soken Chemical Co., Ltd.: /
5W-2B) Polyester prepolymer 30
(Dainichiseika Chemical Co., Ltd. NKS-1> Polyfunctional polyisocyanate 6 (Nippon Polyurethane Co., Ltd. Coronat) Toluene
20 Ethyl acetate 20 An electron beam curable adhesive paint having the above composition was prepared, and a thickness of 25
Coating amount 20 gr/m on μ polyester film
''' (solid content) to form an electron beam curable adhesive layer, and a silicone release paper was laminated to obtain an electron beam curable adhesive sheet. From this electron beam curable adhesive sheet, an adhesive label l for use.

A test piece with a length of cm and a width of 25 mm was prepared, the release paper was peeled off and the test piece was attached to a glass plate, and the adhesive force from the glass plate was measured 24 hours later. Its adhesive strength is 450 gr
/ It was 25mm wide.

Similarly, after 24 hours, an electron beam was applied from the polyester film side to an effective absorbed dose of 2 Mrad (voltage 150
Ke V, current 5 mA) to crosslink and cure the electron beam curable adhesive, and then the adhesive strength was measured. Its adhesive strength is
With a width of 6 gr/25 mm, the adhesive strength could be reduced by electron beam irradiation, and the test piece could be peeled off from the glass plate very easily. After peeling off, no adhesive residue was found on the glass plate.

Comparative Example 1 A test piece was prepared in the same manner as in Example 1 using a commercially available acrylic adhesive, and was irradiated with ultraviolet light under the conditions of Example 1. The adhesive force of 1200 gr/25 mm width became 1350 gr/25 mm width after irradiation, and the test piece could not be easily peeled off from the glass plate. In addition, adhesive residue was found on the glass plate.

Comparative Example 2 A test piece was prepared in the same manner as in Example 3 using a commercially available acrylic adhesive, and was irradiated with an electron beam under the conditions of Example 3. The adhesive force of 850 gr/25 mm width became 920 gr/25 mm width after irradiation, and the test piece could not be easily peeled off from the glass plate. and,
Adhesive residue could be seen on the glass board.

〔Effect of the invention〕

As described above, when a label prepared from an active energy ray-curable adhesive sheet is used as in the present invention, the adhesive strength can be reduced by irradiation with active energy rays, and the adhesive label can be easily peeled off from the bottle. It can be seen that the effect is great.

Patent applicant: Nippon Kako Paper Co., Ltd. Representative Patent Attorney Fukumura San Opening above Patent attorney Akio Seto

Claims (1)

[Claims] Use of a bottle in a label peeling method for a bottle affixed with an adhesive label formed by applying an active energy ray curable adhesive layer to the surface of an active energy ray transparent base material. After that, the label is irradiated with active energy rays in advance to crosslink and cure the active energy ray curable adhesive, thereby reducing the adhesive force of the active energy ray curable adhesive layer and causing the label to peel off. How to remove bottle labels.