JPH06314062A - Thermosensitive tacky adhesive label and method for peeling thermosensitive tacky adhesive label - Google Patents

Abstract

(57) [Abstract] [Purpose] A heat-sensitive adhesive label attached to an adherend is immersed in an aqueous thermal solvent (eg, water, alcohol, aqueous NaOH solution, etc.) to easily dissolve the adhesive layer. The purpose is to easily self-peeling the label base material (peeling by the label itself without external force) to reduce transfer residue of the pressure-sensitive adhesive to the adherend during self-peeling of the pressure-sensitive adhesive label. [Structure] A label display layer 2 is provided on the front surface of a label substrate 1, and a heat-sensitive adhesive composition and a heat-expandable microcapsule containing a polymeric material, a tackifier and a solid plasticizer as basic components on the back surface of the label substrate 1. The heat-sensitive adhesive label A having the heat-sensitive adhesive layer 3 containing the capsule 4 and the water-soluble polymer and the heat-sensitive adhesive label attached to the adherend are immersed in an aqueous solvent at 60 ° C. or higher. A heat-sensitive adhesive label peeling method for peeling.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive label which is used by being adhered to an adherend such as a glass bottle, a plastic bottle or the like, or other articles, and an adhesive label which is peeled off from the adherend. The present invention relates to a peeling and washing method for recovering and reusing an adherend, and more particularly to a heat-sensitive adhesive label of a type that gives tackiness by heat treatment, and a heat-sensitive adhesive label peeling method.

[0002]

2. Description of the Related Art A heat-sensitive adhesive label has a label base material (sheet-like base material) on the surface of which a display such as a picture, a character, and a symbol is provided by printing or the like, and the back surface of the label has a heat-sensitive adhesive composition. It is provided with a heat-sensitive adhesive layer which has been applied and coated. The heat-sensitive adhesive composition is already known, and is described, for example, in "Adhesion Handbook", 12th Edition, page 131 (published by Kobunshi Kogakukai, 1980). That is, the basic composition consists of a polymeric material, a tackifier, and a solid plasticizer, which is not tacky at room temperature, but becomes sticky when heated, and that remains for a considerable period after cooling. Refers to agents (adhesives). Usually, the dry coating film of this pressure-sensitive adhesive is tack-free and does not require release paper.

Here, the polymer material is a component that gives an adhesive force, and is, for example, polyvinyl acetate, copolyethylene-vinyl acetate, polyacrylic acid ester type, polyvinyl chloride type, natural rubber, synthetic rubber, copolyacetic acid. Vinyl-acrylic acid ester, polyester-based and polyurethane-based polymer compounds are used.

The tackifier is a component for enhancing the tackiness when activated by heating, and is, for example, a rosin derivative, a terpene resin system, a petroleum resin system, a phenol resin system, a xylene resin system. Resins such as are used.

The solid plasticizer is solid at room temperature and melts when heated above its melting point, swells and dissolves the polymer material and the tackifier, and develops viscosity and adhesiveness. Let And, since it does not crystallize easily after being melted once, it is possible to take a long time for holding the adhesive after the heat activation. Dimethyl, sucrose benzoate,
Organic compounds that are solid at room temperature, such as ethylene glycol dibenzoate, trimethylolethane tribenzoate, tribenzoic acid glyceride, pentaerythrate tetrabenzoate, sucrose octaacetate, and tricyclohexyl N-cyclohexyl-P-toluenesulfonamide citrate, It is used.

A heat-sensitive adhesive composed of an aqueous resin dispersion containing the above polymeric material, tackifier, and solid plasticizer as basic components is applied to at least one side of a substrate such as paper or film and dried. By doing so, a heat-sensitive adhesive sheet is produced, and the heat-sensitive adhesive label is produced by appropriately punching and cutting the heat-sensitive adhesive sheet into small pieces having a label shape.

The heat-sensitive adhesive label obtained by applying a heat-sensitive adhesive obtained by mixing a polymer material, a tackifier and a solid plasticizer to at least one side of a substrate such as paper or film and drying it is heated. Then, the pressure-sensitive adhesive layer is activated to give tackiness, and then the pressure-sensitive adhesive layer is attached to various adherends.

[0008]

The heat-sensitive adhesive label is, for example, a glass plate, a stainless plate, a polyethylene plate,
It is used by adhering it to an adherend such as a polyester film or various containers such as glass bottles and plastic bottles, and other articles, etc. In the case of peeling from the body, there is a difference in adhesive strength (bonding strength) depending on the adherend, but the adhesive layer is firmly transferred to the adherend side and remains, so it is not peeled off cleanly, It takes a lot of labor to remove the pressure-sensitive adhesive remaining on the adherend, or the label substrate is ruptured or the like, which makes it difficult to peel it off easily. In addition, even if the adhered material is dipped in a hot solvent (for example, water, alcohol, an aqueous solution of NaOH, etc.), it does not easily peel off itself (the label itself peels off without external force). It did not have a self-peeling function.

The present invention has been made by paying attention to such a problem, and the problem is that a heat-sensitive adhesive label attached to an adherend is placed in an aqueous hot solvent (for example, The adhesive layer is easily dissolved by immersing in water, alcohol, NaOH aqueous solution, etc., and the label substrate is easily self-peeled (peeled by the label itself without external force), and the adherend when self-peeling the adhesive label It is to reduce the transfer residue of the adhesive to the adhesive.

[0010]

The first invention of the present invention is as follows:
A label display layer 2 is provided on the front surface of the label substrate 1, and a heat-sensitive adhesive composition containing a polymeric material, a tackifier and a solid plasticizer as basic components on the back surface of the label substrate 1, and thermally expandable microcapsules 4. A heat-sensitive adhesive label comprising a heat-sensitive adhesive layer 3 containing a water-soluble polymer.

A second invention of the present invention is the heat-sensitive adhesive label attached to an adherend after heat-activating the heat-sensitive adhesive layer of the above-mentioned heat-sensitive adhesive label to impart tackiness. 6
It is a method for peeling a heat-sensitive adhesive label, which comprises immersing in an aqueous solvent at 0 ° C. or higher and peeling.

[0012]

EXAMPLES The heat-sensitive adhesive label of the first invention of the present invention will be described in detail with reference to the examples. FIG. 1 is a side sectional view showing the heat-sensitive adhesive label of the first invention. 1
A label display layer 2 of patterns, characters, symbols, etc. is formed by printing on the front surface of the, and the back surface of the label substrate 1 is thermally expanded into a basic component composed of a polymer material, a tackifier and a solid plasticizer. The heat-sensitive adhesive layer 3 containing the water-soluble microcapsules 4 and the water-soluble polymer is applied. A release sheet (not shown) may be attached to the heat-sensitive adhesive layer 3 so that it can be easily peeled off, if necessary. In the present invention, it is possible to appropriately provide a display protective layer on the label display layer 2 with a transparent resin.

As shown in FIG. 1, the above-mentioned heat-sensitive adhesive label uses a label base material 1 such as a sheet material or a tape material made of paper, a plastic film or the like, or a composite material thereof. The surface of the label substrate 1 is provided with a display layer 2 having a picture, a character, a symbol, etc. by printing or the like, and at least the back surface of the label substrate 1 is a heat-sensitive adhesive containing a polymeric material, a tackifier and a solid plasticizer as basic components. A heat-sensitive adhesive layer 3 is provided by applying a heat-sensitive adhesive composition containing a heat-expandable microcapsule 4, a water-soluble polymer and an appropriate aqueous solvent to the composition and drying the composition. The heat-sensitive adhesive label is heat-activated to impart adhesiveness to the heat-sensitive adhesive layer 3, and then appropriately attached to a container or other article (adherend) for use.

The polymer material which is a basic component of the heat-sensitive adhesive composition which constitutes the heat-sensitive adhesive layer 3 is a component which gives an adhesive force, and is, for example, polyvinyl acetate, copolyethylene-vinyl acetate, polyacryl. Polymer compounds of acid ester type, polyvinyl chloride type, natural rubber, synthetic rubber, copolyvinyl acetate-acrylic acid ester, polyester type, polyurethane type are used.

The tackifier, which is a basic component of the heat-sensitive adhesive composition, is a component for enhancing the adhesiveness when activated by heating, and is, for example, a rosin derivative, a terpene resin system, a petroleum resin. Resins such as resin, phenol resin, xylene resin, etc. are used.

The solid plasticizer, which is the basic component of the heat-sensitive adhesive composition, is solid at room temperature and melts when heated above its melting point to swell and dissolve the polymer material and tackifier. Then, it develops stickiness and adhesiveness. And, since it does not crystallize easily once it is melted, it can take a long time to retain the adhesive after heat activation, for example, diphenyl phthalate, dihexyl phthalate, dicyclohexyl phthalate, dihydroabietyl phthalate, dimethyl isophthalate. At room temperature, sucrose benzoate, ethylene glycol dibenzoate, trimethylolethane tribenzoate, glyceride tribenzoate, pentaerylate tetrabenzoate, sucrose octaacetate, tricyclohexyl N-cyclohexyl-P-toluenesulfonamide citrate, etc. Solid organic compounds have been used.

The heat-sensitive adhesive composition constituting the pressure-sensitive adhesive layer 3 of the heat-sensitive adhesive label of the first invention comprises a basic component consisting of the polymer material, tackifier and solid plasticizer as described above, Heat-expandable microcapsules 4, water-soluble polymer,
It appropriately contains an aqueous solvent, and represents a resin aqueous dispersion as a whole composition.

The heat-expandable microcapsules 4 are those in which a polymer of an outer shell material encloses a core substance, and when the temperature is raised, the encapsulated core substance is gasified and the microcapsules themselves swell like balloon balls. It is a thing.

The outer shell material is classified into an inorganic type and an organic type, and typical examples thereof include glass, silica, shirasu, carbon, phenol, vinylidene chloride, vinylidene chloride / acrylonitrile copolymer, alumina and zirconia. is there.

Examples of the core substance to be encapsulated include hydrocarbons such as isobutane and propane, and a foaming agent such as sodium bicarbonate, azobisisobutyronitrile and ammonium carbonate may be used.

The expansion start temperature can be adjusted by changing the combination of the outer shell material and the core material. The particle size of these heat-expandable microcapsules 4 is preferably in the range of 1 to 100 μm, and particularly preferably in the range of 10 to 30 μm. The expansion start temperature is preferably in the range of 60 ° C to 120 ° C, and particularly preferably in the range of 80 ° C to 100 ° C.

The water-soluble polymer is roughly classified into a natural polymer, a semi-synthetic product and a synthetic product, and the polymer is soluble in water. Natural polymers include starchy substances (sweet potato starch, potato starch,
Tapioca starch, wheat starch, corn starch), mannan (konjac), seaweed (funnel, agar, sodium alginate), plant mucilage (troloois, tragacanth gum, acacia gum), protein (a glue, gelatin, casein,
Collagen).

The semi-synthetic products include cellulose-based products (viscose, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, and starch-based products (soluble starch, carboxymethyl starch, dialdehyde starch). Polyvinyl alcohol, polyacrylate, polyethylene oxide,
Examples include rosin salts, maleated rosin salts, and polyisobutylene / maleic anhydride copolymers.

In the heat-sensitive adhesive composition which constitutes the heat-sensitive adhesive layer 3 of the first invention, polymer materials, tackifiers, solid plasticizers, heat-expandable microcapsules 4 and water-soluble polymers are preferred. The compounding ratio is 20 to 150 parts by weight of the tackifier, 30 to 300 parts by weight of the solid plasticizer, 0.1 to 50 parts by weight of the heat-expandable microcapsule, and water-soluble with respect to 100 parts by weight of the polymer material. The amount of the polymer is 1 to 100 parts by weight, but is not limited thereto.

FIG. 2 is a side sectional view showing a state in which the heat-sensitive adhesive label A according to the first invention is attached to the surface of the adherend 5. The heat-sensitive adhesive label A is placed on the adherend 5. The label A is placed on the upper surface of the label A and then heat-treated at a temperature of 100 ° C. or higher for several seconds (heating amount h) to activate the heat-sensitive adhesive layer 3 to impart adhesiveness, The heat-sensitive adhesive layer 3 having adhesiveness is attached to the surface of the adherend 5.

The heat-sensitive adhesive label A is adhered to the adherend 5 with the heat-expandable microcapsules 4 contained in the heat-sensitive adhesive layer 3 slightly heat-expanded by the heat treatment (heat amount h).
It is attached to the surface.

Next, the heat-sensitive adhesive label peeling method of the second invention of the present invention will be described in detail below according to the embodiment shown in FIGS. 3 (a) and 3 (b). When peeling, first, see FIG.
As shown in (a), the heat-sensitive adhesive label A attached to the surface of the adherend 5 is an aqueous solvent w that is heated to 60 ° C. or higher.
Immerse in (water, alcohol) for several minutes. Due to the heat of the aqueous solvent, the non-expandable thermally expandable microcapsules 4 contained in the heat-sensitive adhesive layer 3 are thermally expanded to form an expansion space in the heat-sensitive adhesive layer 3, and the aqueous solvent w
Penetrates into the entire heat-sensitive adhesive layer 3 through the expansion space to promote the dissolution of the heat-sensitive adhesive layer 3, and the heat-sensitive adhesive layer 3
Immediately begins to dissolve due to the invading aqueous solvent w,
It becomes easy to peel off, and eventually self-peeles within a few minutes.

[0028]

The heat-sensitive adhesive label A according to the present invention contains a water-soluble polymer and heat-expandable microcapsules 4 in a heat-sensitive adhesive layer 3 containing a polymeric material, a tackifier and a solid plasticizer as basic components. is doing.

As a result, for example, 50 ° C. or 60 ° C.
Heat-sensitive adhesive label A in the above aqueous heating solvent for 1 minute to
When immersed in the heat-sensitive adhesive layer 3 for several minutes, the water-soluble polymer contained in the heat-sensitive adhesive layer 3 has an increased solubility in a heated aqueous solvent, and the heat-sensitive adhesive layer 3 contains the heat-expandable polymer. The microcapsules are further expanded by the heat of the heating solvent to generate an expansion space in the heat-sensitive adhesive layer 3, the penetration of the aqueous solvent into the adhesive layer 3 is promoted, and the adhesive layer 3 is dissolved. Is promoted.

By promoting the dissolution of the heat-sensitive adhesive layer 3, self-peeling to the adherend 5 progresses, and due to the progress of self-peeling, the contamination of the adherend 5 due to the residual of the adhesive layer 3 is caused. It can be improved over the conventional one.

Further, the heat-sensitive adhesive label A stuck to the adherend 5 through the above heat-sensitive adhesive layer 3 of the present invention is 50
When immersed in a water-based heating solvent having a temperature of 60 ° C. or 60 ° C. or higher for 1 minute to several minutes, the heat-sensitive adhesive layer 3 on the back surface of the label substrate 1 extends in the direction in which the heat-expandable microcapsules 4 expand, For example, it is self-peeling while curling outwardly from the body 5.

Specific examples of the heat-sensitive adhesive label of the present invention are shown below.

Example 1 Aqueous emulsion of acrylic acid ester copolymer as polymer material (solid content) 100 parts by weight Aqueous emulsion of rosin ester as tackifier (softening point 84 ° C.) (solid content) 100 parts by weight As a solid plasticizer Dicyclohexyl phthalate aqueous dispersion (melting point 64 ° C.) (solid content) 100 parts by weight As thermally expandable microcapsules (particle size 10 to 20 μm, expansion starting temperature 80 ° C.) outer shell material; vinylidene chloride / acrylonitrile copolymer Core substance; heat-expandable microcapsule using isobutane (solid content) 10 parts by weight Sodium polyacrylate as water-soluble polymer (solid content) 10 parts by weight

These were mixed with a lower alcohol solvent having a solid content concentration of 50% to prepare a heat-sensitive adhesive composition exhibiting an aqueous resin dispersion (emulsion).

Then, the above heat-sensitive adhesive composition was added to 25 μm.
m polyester film is applied to one side of the label substrate and dried at 45 ° C. for 2 minutes.
A heat-sensitive adhesive label having a μm-thick heat-sensitive adhesive layer was produced.

Example 2 A heat-sensitive adhesive label was produced in the same manner as in Example 1 except that the amount of the heat-expandable microcapsules added in Example 1 was changed from 10 parts by weight to 20 parts by weight. .

<Example 3> A heat-sensitive adhesive label was prepared in the same manner as in Example 1 except that the water-soluble polymer (sodium polyacrylate) in Example 1 was changed to an aqueous sodium salt solution of maleated rosin. did.

Comparative Example 1 A heat-sensitive adhesive label was produced in the same manner as in Example 1 except that the water-soluble polymer in Example 1 was not added.

Comparative Example 2 A heat-sensitive adhesive label was produced in the same manner as in Example 1 except that the thermally expandable microcapsules in Example 1 were not added.

Next, in order to check the characteristics of these heat-sensitive adhesive labels, confirmation tests were conducted on the following items, and the results shown in Table 1 below were obtained.

The confirmation test of the heat-sensitive adhesive label is 80 mm.
12 x 130 mm size heat-sensitive adhesive labels
By heating for 20 seconds at 0 ° C., the solid plasticizer in the heat-sensitive adhesive composition is thermally activated to give tackiness, and the adhesive is adhered to an adherend (glass plate) to obtain an adhered material. The kimono is immersed in various aqueous hot solvents, and the self-peeling property (peeling state), the peeling time, and the staining property of the label substrate are observed. The self-peeling property means that the label itself is peeled off without an external force, the peeling time means the time until self-peeling, and the stain property means the adhesive on the adherend surface after self-peeling. It shows the residual adhesion condition of.

[0042]

[Table 1]

[0043]

The heat-sensitive adhesive label of the present invention is obtained by applying a heat-sensitive adhesive composition of a resin aqueous dispersion (emulsion type) containing heat-expandable microcapsules and a water-soluble polymer onto a label substrate. A heat-sensitive adhesive label provided with the resulting heat-sensitive adhesive layer, which is heat-activated to be adherend (for example,
The heat-sensitive adhesive label of the present invention adhered to a glass plate, a stainless plate, a polyethylene plate, a polyester film, etc., has peel resistance against cold water, room temperature water, or other cooled or room temperature aqueous solvent, By immersing in an aqueous hot solvent of 60 ° C. or higher (for example, water, alcohol, aqueous NaOH solution, etc.), self-peeling can be easily carried out, and there is an effect that the transfer residue of the adhesive on the adherend is reduced.

[Brief description of drawings]

FIG. 1 is a schematic side sectional view of a heat-sensitive adhesive label of the first invention.

FIG. 2 is a schematic side sectional view showing a state in which the heat-sensitive adhesive label of the first invention is attached to an adherend.

3 (a) and (b) are heat-sensitive adhesive of the second invention in which the heat-sensitive adhesive label of the first invention adhered to an adherend is immersed in an aqueous solvent at 60 ° C. or higher for peeling. It is a sectional side view explaining a label peeling method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Substrate 2 ... Display layer 3 ... Thermosensitive adhesive layer h ... Heating amount w ... Aqueous solvent

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Yuka Imai 1-5-1 Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd. (72) Kenjiro Kuroda 1-5-1 Taito, Taito-ku, Tokyo Toppan Imprint Co., Ltd. (72) Inventor Yasuo Kubo 2-33 Kyobashi, Chuo-ku, Tokyo Toyo Inki Manufacturing Co., Ltd.

Claims (2)

[Claims] 1. A heat-sensitive adhesive composition comprising a label display layer 2 on the surface of a label base material 1, and a back surface of the label base material 1 comprising a polymeric material, a tackifier and a solid plasticizer as basic components, and thermal expansion. A heat-sensitive adhesive label comprising a heat-sensitive adhesive layer 3 containing a water-soluble polymer and a hydrophilic microcapsule 4. 2. The heat-sensitive adhesive label adhered to an adherend after heat-activating the heat-sensitive adhesive layer of the heat-sensitive adhesive label according to claim 1 to give an adhesive property, A method for peeling a heat-sensitive adhesive label, which comprises immersing in an aqueous solvent and peeling.