JP2002003817A - Delayed tack pressure-sensitive adhesive composition and pressure-sensitive adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a pressure-sensitive adhesive composition which m used for e.g. a label, a tape, and a seal for a package, requiring no release paper, capable of being readily peeled off by hand while satisfying such characteristics in practical use as the adhesive power and blocking resistance, and useful for the recycling of bottles, and the like, and which therefore serves to save resources and can get an economical advantage, and a pressure-sensitive adhesive sheet made by using this composition. SOLUTION: The pressure-sensitive adhesive composition of delayed tack type contains (1) an aqueous dispersion of a thermoplastic resin which is non- tacky at room temperature or below, (2) a solid plasticizer, (3) a tackifier, and (4) a filler having a mean particle diameter of 2 μm or larger and hardly soluble in water. The pressure-sensitive adhesive sheet of delayed tack type is made by coating a support with the composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a thermosensitive composition which is non-tacky at room temperature but develops tackiness when heated, and maintains tackiness for a while even after a heating source is removed after the tackiness is developed. The present invention relates to a delayed tack type pressure-sensitive adhesive and a pressure-sensitive adhesive sheet having delayed tack type tackiness.

[0002]

2. Description of the Related Art As described in "Adhesion Handbook" (12th edition, published in 1955, issued by the High Polymer Publishing Association), conventional heat-sensitive delayed-tack adhesives are thermoplastic resins and tackifying resins. And a solid plasticizer as a basic skeleton. The thermoplastic resin is the basis of the pressure-sensitive adhesive, and without this, no cohesive force can be obtained during use. In addition, solid plasticizers do not impart plasticity to the resin at room temperature, and melt first into the resin when heated to swell or soften the resin. Acts to express Label adhesives must not be peeled off during transportation or at a store during the exhibition period, nor should they be peeled off by condensation after being stored in a refrigerator or the like. However, recycling of bottle containers has recently been demanded from the viewpoint of environmental protection, and accordingly, it has been demanded that labels of bottle containers and the like can be easily peeled at home by ordinary consumers.

For the purpose of improving the removability, an acrylic delayed tack adhesive containing an aqueous dispersion of a thermoplastic resin, a solid plasticizer and a tackifier is applied in an amount of 10 to 18 g / g.
Japanese Patent Application Laid-Open (JP-A) No. 8-76689 discloses a method for setting the value in the range of m2. However, it is necessary to use an alkaline solution for peeling, and it is difficult to use the compound in ordinary households. Also, a method using a spherical adhesive as a removable adhesive is known, but it is a pressure-sensitive adhesive that is tacky even at room temperature and requires release paper or a substitute for it. From the viewpoint, it was not suitable for the purpose of the present invention.

That is, a conventional glass bottle label using a heat-sensitive delayed-tack type adhesive has problems that, for example, it is difficult to remove the label from the glass bottle by hand at home or the label paper may be broken. Had.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a release paper which can be easily peeled off by hand and is useful for recycling bottles and the like, while satisfying practical properties in both adhesive strength and blocking property. It is an object of the present invention to provide a pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet which can pursue economical benefits by saving resources as unnecessary labels, tapes, seals for packages, and the like.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to overcome the above-mentioned problems, and as a result, paper coated with a delayed tack adhesive containing a hardly water-soluble filler having a specific particle size range. Although the film and the film are in close contact with the bottle and the like, they have found that they can be easily peeled off by hand at room temperature, and have reached the present invention.

That is, the first configuration of the present invention is as follows:
An aqueous dispersion of a thermoplastic resin having no tack at room temperature or lower,
A delayed tack-type pressure-sensitive adhesive composition comprising (2) a solid plasticizer, (3) a tackifier, and (4) a poorly water-soluble filler having an average particle size of 2 μm or more.

The second constitution of the present invention comprises (1) an aqueous dispersion of a thermoplastic resin having no tack at room temperature or lower, (2) a solid plasticizer, (3) a tackifier, and (4) an average particle. Diameter 2
A delayed-tack-type pressure-sensitive adhesive sheet, which is obtained by coating a support with a delayed-tack-type pressure-sensitive adhesive composition containing a poorly water-soluble filler having a size of at least one micron.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The pressure-sensitive adhesive composition according to the present invention comprises (1) an aqueous dispersion of a thermoplastic resin having no tackiness at room temperature or lower, (2) a solid plasticizer, and (3) a tackifier. And (4) the poorly water-soluble filler having an average particle diameter of 2 microns or more will be described in detail.

By using a delayed tack type adhesive containing a poorly water-soluble filler in a specific particle size range and further a specific amount of a filler, when the adhesive sheet coated with the composition is adhered to a bottle or the like, Although it does not peel off naturally, it can be controlled to a peeling strength that can be easily peeled off by hand at room temperature. Normally, if a large amount of filler is added, even a thermally activated delayed tack adhesive will not be able to adhere to an adherend due to too low peel strength, or will be easily peeled off when a bottle rubs. was there. Also, depending on the type of filler, the initial adhesive strength is reduced when it is blended, and it is possible to remove again, but with the passage of time, the adhesive leaches out to the interface and the adhesive strength gradually increases, and it does not come off from bottles etc. was there. In particular, when a filler having a small particle size was added, the tendency was remarkable. The hardly water-soluble filler of the specific particle size range according to the present invention, and further, by blending a specific amount of the filler, does not peel off naturally due to contact with a bottle, but has an adhesive strength that can be easily peeled off by hand or the like. It can be a delayed tack adhesive. Delayed tack adhesives usually have a solid content of 5 to 30 g based on paper or film.
In the present invention, depending on the coating thickness of the pressure-sensitive adhesive, the peel strength can be controlled over a long period of time by adding a filler having a specific particle size range. Was found.

As the thermoplastic resin used in the present invention, a resin having no tackiness at room temperature or lower, that is, a resin having a glass transition temperature of at least -20 ° C. or higher is used. For example, acrylate, styrene-acrylate, styrene-butadiene, vinyl acetate, ethylene-vinyl acetate, vinyl acetate-acrylate, ethylene-vinyl chloride, ethylene-acrylate, ethylene-acrylic acid, polybutadiene, urethane, Styrene-isoprene block polymer and the like.

Examples of the solid plasticizer include diphenyl phthalate, dihexyl phthalate, dicyclohexyl phthalate, dihydroabiethyl phthalate, dimethyl isophthalate, sucrose benzoate, and ethylene glycol dibenzoate.
And trimethylol triethane tribenzoate, glyceride tribenzoate, pentaerythritol tetrabenzoate, sucrose octaacetate, tricyclohexyl citrate, N-cyclohexyl-p-toluenesulfonamide and the like. The preferred melting point of the solid plasticizer is from 50 to 110C, more preferably from 60 to 90C.

Further, as tackifiers for improving the adhesive performance of the pressure-sensitive adhesive, for example, terpene resins, aliphatic petroleum resins, aromatic petroleum resins, cumarone-indene resins, styrene resins, phenol resins, terpene resins Phenolic resins, rosin derivatives (rosin, polymerized rosin, hydrogenated rosin and their esters with glycerin, pentaerythritol and the like, resin acid dimer and the like). The solid plasticizer, the thermoplastic resin and the tackifier may be used alone or as an aqueous emulsion or an organic solvent solution.
More than one mixture can be used. Further, a dispersant, an antifoaming agent, a thickener and the like can be used as needed.

Further, a small amount of a solid emulsifier may be added.
In general, among fatty acid soaps and alkylphenylalkylene oxides as emulsifiers, those solid at room temperature are preferable in order to prevent blocking properties of the pressure-sensitive adhesive.

As the poorly water-soluble filler, polyurethane,
Organic fillers made of resin beads such as polyacryl, polyamide, silicone resin, fluorine resin, and epoxy resin, and inorganic fillers made of inorganic compound fine particles such as silica and calcium carbonate can be given. A filler which is insoluble and has an average particle size of 2 μm or more, preferably 5 to 20 μm, and more preferably a filler having a wide particle size distribution is preferred.

As the organic filler, for example, polyurethane resin (Burnock CFR: manufactured by Dainippon Ink and Chemicals, Inc.), polyacrylic resin (Techpolymer BMX: manufactured by Sekisui Plastics Co., Ltd., etc.), polyamide, silicone resin (KMP598: Resin beads such as Shin-Etsu Chemical Co., Ltd.), fluorine resin, epoxy resin, and benzoguanamine resin (Eposter L15: manufactured by Nippon Shokubai Co., Ltd.).

As the inorganic filler, for example, oxide,
Hydrates, inorganic acid salts, ammonium salts, metal compounds, and the like can be mentioned, but oxides, hydroxides, nitrates, carbonates, phosphoric acids, sulfates, oxalates of organic acid salts, and acetic acid are preferred. Salts, tartrate, citrate are used.
Examples of the oxide include magnesium oxide, aluminum oxide, titanium oxide, barium oxide, titanium barium oxide, aluminum barium oxide, aluminum magnesium oxide, and silicon oxide. Further, these fillers are preferably added in an amount of 0.1% or more of the blend. Particularly preferably, 0.5 to 5% is added. If the addition amount is less than 0.1%, re-peelability is hardly exhibited.

[0018]

The present invention will be specifically described below with reference to examples. However, the scope of the present invention is not limited at all by the following examples. In the examples, parts are parts by weight,%
Means weight%.

Example 1 SBR latex (styrene / butadiene / acrylic acid = 87/10/3: Tg60
C) 100 parts, rosin (Hariester DS-90E: manufactured by Harima Kasei Co., Ltd.) 60 parts, powdered dicyclohexyl phthalate 160 parts (melting point 63 ° C.) and granular silica (Sylysia 470 (average particle size 12 μ)): Fuji Silysia Chemical Aqueous dispersion containing 1 part (solid content 50%)
Was adjusted. Next, the amount of the obtained pressure-sensitive adhesive applied was 20 g /
m2, apply directly on one-sided art paper at 40 ° C.
Dried for minutes. In this state, no tackiness could be confirmed. Table 1 shows the results of evaluation of the adhesion and blocking properties of the coated product. Further, the coated product was heated at 120 ° C. for 1 minute to exhibit adhesiveness, and then bonded to a glass plate to measure the initial adhesive strength. Table 1 shows the results of measuring the adhesive strength after storage at 40 ° C. for one week and two weeks.

Example 2 An adhesive was used in the same manner as in Example 1 except that 1 part of granular silica (Sylysia 470 (average particle size: 12 μ): manufactured by Fuji Silysia Chemical Ltd.) was changed to 3 parts. Prepared, directly applied on one side art paper, dried,
Table 1 shows the results of evaluation of the coated product.

Example 3 Instead of 1 part of granular silica (Silysia 470 (average particle size: 12 μm: manufactured by Fuji Silysia Chemical Ltd.)) in Example 1, the same amount of bead-like crosslinked silicone resin (KMP597 (average particle size)) was used. Particle size 5μ): An adhesive was prepared in the same manner as in Example 1 except that the composition was changed to Shin-Etsu Chemical Co., Ltd.), applied directly to one-sided art paper, dried, and evaluated for the coated product. It is shown in FIG.

Example 4 Instead of 1 part of granular silica (Silysia 470 (average particle size: 12 μ): manufactured by Fuji Silysia Chemical Ltd.) in Example 1, the same amount of bead-like crosslinked polyurethane (Bernock CFB100 (average particle size)) was used. Diameter 15μ):
Example 1 except that Dainippon Ink and Chemicals, Inc.) was used.
Prepare an adhesive in the same manner as above, apply directly on one side art paper,
Table 1 shows the results of evaluation of the coated product after drying.

Example 5 Instead of 1 part of granular silica (Silysia 470 (average particle size: 12 μm), manufactured by Fuji Silysia Chemical Ltd.) in Example 1, the same amount of bead-like crosslinked polybutyl methacrylate (Techpolymer) A pressure-sensitive adhesive was prepared in the same manner as in Example 1 except that BMX-12 (average particle size: 12 μm: manufactured by Sekisui Chemical Co., Ltd.) was applied directly onto one-sided art paper, dried, and evaluated for the coated product. Table 2 shows the results.

Comparative Example 1 An adhesive was prepared in the same manner as in Example 1 except that 1 part of granular silica (Silysia 470 (average particle size: 12 μm), manufactured by Fuji Silysia Chemical Ltd.) was not used. Table 2 shows the results of evaluation of the coated product after directly coating and drying on one-sided art paper.

Comparative Example 2 Instead of 1 part of granular silica (Silysia 470 (average particle size: 12 μm) manufactured by Fuji Silysia Chemical Ltd.) in Example 1, the same amount of granular silica (Silysia 350 (average particle size: 1 0.8 μ): An adhesive was prepared in the same manner as in Example 1 except that the product was changed to Fuji Silysia Chemical Ltd.), directly applied on one-sided art paper, dried, and the coated product was evaluated. Shown in

The following methods were used to evaluate the initial and post-storage adhesive strengths for evaluating the ease of peeling of the adhered product to the bottle in Examples and Comparative Examples, and the blocking properties for evaluating the storage stability of coated products. Was evaluated by.

[0027] Initial adhesive strength: After the development of adhesiveness by heating, the adhesive-coated product was immediately attached to a float glass plate, and the adhesive strength was measured by peeling at 180 degrees according to JIS K-6848. Judged. However, the glued part is 100mm
And ◎: Adhesive strength is 1 to 2.5 N / 15 mm and is sufficiently adhered to the bottle, but can be easily peeled off by hand. ：: Adhesive strength of 0.5 N / 15 mm or more and less than 1 N / 15 mm and no spontaneous peeling, or 2.5 N / 15 mm or more and less than 5 N / 15 mm and strong peel strength, but somehow peelable by hand. ×: When the adhesive strength is less than 0.5 N / 15 mm, it is easily peeled off naturally, and 5
If N / 15mm or more, strong force is required to peel off,
Label paper tears and remains in bottle.

Adhesive strength after storage: After the development of tackiness by heating, the adhesive-coated product was immediately stuck to a float glass, stored in a soaking dryer at 40 ° C. for a predetermined time, left at room temperature for 1 hour, and then JIS K An adhesive strength test was performed according to -6848, and the evaluation was made based on the same criteria as the initial adhesive strength.

Blocking property: A pressure-sensitive adhesive coating was applied under a load of 0.1 mPa, peeled after storage at 40 ° C. for 24 hours, and evaluated according to the following criteria. ◎ ・ ・ ・ ・ ・ ・ No peeling resistance.・ ・ ・: There is a slight noise when peeling. ×: The fiber of the paper is pulled at the time of peeling.

[0030]

[Table 1]

[0031]

[Table 2]

The unit in Table 1 is N / 15 mm, and P indicates substrate breakage.

[0033]

According to the present invention, as compared with a conventional heat-sensitive delayed-tack type pressure-sensitive adhesive-coated pressure-sensitive adhesive sheet, it can be easily peeled off by hand while satisfying practical properties in both adhesive strength and blocking property. It is possible to obtain a pressure-sensitive adhesive sheet which is useful for recycling bottles and the like. The industrial significance of being able to pursue economical benefits by saving resources, such as labels, tapes, and packaging seals that do not require release paper, is extremely significant.

Continuing on the front page F-term (reference) 4J004 AA02 AA04 AA05 AA06 AA09 AA10 AA11 AA14 AA18 AB01 4J040 BA192 BA202 CA031 CA081 DA031 DA071 DB002 DB051 DB061 DC041 DC092 DE021 DF002 DF041 DK012 HA001 002 001 002 001 HB34 JA03 JA09 JB09 KA03 KA26 KA31 KA42 LA08 LA09

Claims (4)

[Claims] (1) an aqueous dispersion of a thermoplastic resin having no tack at room temperature or lower, (2) a solid plasticizer, (3) a tackifier, and (4) an average particle diameter of 2 microns or more. A delayed tack-type pressure-sensitive adhesive composition comprising a poorly water-soluble filler. 2. The delayed tack type pressure-sensitive adhesive composition according to claim 1, wherein the addition amount of the poorly water-soluble filler is 0.5% by weight or more. 3. The poorly water-soluble filler has an average particle size of 5-2.
3. The delayed tack type pressure-sensitive adhesive composition according to claim 1, wherein the pressure-sensitive adhesive composition has a diameter of 0 micron. 4. An aqueous dispersion of (1) a thermoplastic resin having no tack at room temperature or lower, (2) a solid plasticizer, (3) a tackifier, and (4) an average particle diameter of 2 microns or more. A delayed-tack-type pressure-sensitive adhesive sheet comprising a support and a delayed-tack-type pressure-sensitive adhesive composition containing a poorly water-soluble filler.