JPS587532B2 - label no tenchiyakuhouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method of adhering a hydrophobic label (base paper) to a hydrophobic adherend material using an adhesive. There are those who try to label their comrades extremely efficiently.

Although many methods for attaching hydrophobic labels to hydrophobic materials such as synthetic paper and aluminum foil have been developed and put into practice, there is still no way to attach labels efficiently and inexpensively. There are almost no technologies available, especially those using non-absorbent or poorly absorbent materials, such as synthetic resins, metal foils, metal-deposited products, synthetic resin-impregnated papers, and composites of these materials. In the case of labels and attached materials such as plastic bottles, glass bottles, etc., there are technical difficulties, and no satisfactory solution has yet been proposed.

Recently, in the case of non-water-absorbing or non-water-absorbing materials,
Techniques have been shown in which emulsion-based adhesives such as synthetic resins and rubber, or water-, heat-, and pressure-activated adhesives are applied to labels and activated when the label is pasted; however, water-soluble, emulsion-based, and solvent-based adhesives When using adhesives, the initial adhesion strength is extremely poor because both the label and the material to which they are attached are non-water-absorbing or poorly absorbing materials, and it takes an extremely long time to reach practical adhesive strength after the label is pasted. Hours, sometimes days,
Moreover, pressure-activated adhesives cannot be applied to continuous automatic labeling technology and require a step of adhering the glue to the label in advance, which is inevitably an expensive process. In addition, the pressure-activated type requires a separator (release paper).

Water and heat activated adhesives require activation equipment.
Furthermore, when plastic films and the like are heated, they tend to have disadvantages such as melting, deterioration, discoloration, fading, and shrinkage, and of course have the drawback of extremely low efficiency.

In view of the above circumstances, the present invention improves the pasting technology using adhesives, and makes it possible to pasted labels on non-water-absorbent or poorly water-absorbent materials, which has been difficult in the past. A hot-melt adhesive that is sticky at room temperature without any processing is used, and the viscosity of this adhesive during use (when applying the label) is 100,000C. p. By applying heat treatment to reduce the temperature to less than S, it is more efficient than conventional technology.
The adhesive strength makes it possible to attach labels at low cost and with high quality.

That is, the present invention provides a method for pasting a label and a material to be pasted, both of which are non-water-absorbent or poorly water-absorbent, through an adhesive using a continuous automatic labeling machine, in which an ethylene-vinyl acetate copolymer 2 is used as the adhesive. ~75% by weight, using a hot melt adhesive that is sticky at room temperature and consisting of a urethane prepolymer and an α-pinene-phenol copolymer, heating the adhesive until it has a viscosity of less than ioo, ooo centipoise, The object of the present invention is to provide a method for attaching a label, which is characterized in that the label is transferred onto a label, and then the label is attached to a material to be attached.

In the practice of the present invention, the hot-melt adhesive that has stickiness at room temperature is made of ethylene-vinyl acetate copolymer 2-
75 weight percent, and consists of a urethane prepolymer and an α-pinene-phenol copolymer.

Ethylene-vinyl acetate copolymer is vinyl acetate monomer 5
A copolymer of more than % by weight with ethylene monomer is used, which is a common hot melt adhesive.

Urethane prepolymers are polyols, as can be seen on pages 76 and 82 of "Plastic Materials Course ■ Polyurethane Resins" (written by Keiji Iwata, published by Nikkan Kogyo Shimbun, second edition published on November 30, 1962). It is a compound having a free incyanate group obtained by reacting inocyanate with a diisocyanate.

α-Pinene-phenol copolymer is a type of adhesive resin.

In addition to these three ingredients, waxes, plasticizers, tackifiers,
Of course, it is optional to add melt viscosity modifiers, oxidation and decomposition inhibitors, etc. to adjust softening point, set time, blocking, and various polymerization agents for flowability adjustment during coating.

In the present invention, the above-mentioned hot-melt agent that is sticky at room temperature and suitable for labeling is used as an adhesive, but this adhesive has a viscosity of 100,000 c. p. It is necessary to heat the material to a temperature below s, which is another feature of the present invention.

If the viscosity is too high, the transferability of the adhesive from the transfer roll to the label base paper will be poor, and the adhesive will become stringy, making continuous operation impossible.

Various techniques can be used as heating means, but if the "glue pot" and "transfer roll" in conventional labeling machines are designed to be heatable, there is no need to heat the entire device, and adhesives can be easily bonded. The viscosity of the agent is 100,000 c. p. s
Preferably 50,000C. p. Can be adjusted to S.

Incidentally, the viscosity of conventionally used glues (starch glue and emulsion type) is 3,000 to 150,000 C when applied by machine.
．． p. S, 100-50,000 c. for hand pasting. p. It is s.

In addition, if the label is synthetic paper made from stretched resin film,
For example, in the case of ``Yupo FP'' (trade name) made by Oji Yuka Synthetic Paper ■, the temperature when applying the adhesive should be set to a temperature that does not cause enough shrinkage to deform the label. .

(Example) Label: Oji Yuka Synthetic Paper ■ Synthetic paper Product rot Yupo FP #110 ;Labeling machine: ■Labeling machine manufactured by Mei Seisakusho LAB-2 improved version, glue point and transfer The processes in between, including rolls, are It has heat enabled.

Adhesive: Mitsubishi Yuka Products C (M) Ethylene-vinyl acetate copolymer 7.5 Weight section (Vinyl acetate content 10%) urethane prepolymer 50% by weight α-pinene-phenol copolymer 42.5% by weight hot melt adhesive consisting of Adhesive material: Polypropylene cylindrical bottle A bottle made of American polypropylene was flame treated.

(Comparative Example 1) Ethylene-vinyl acetate copolymer pellets (
Toyo Soda #Ultrasen UE-720, MFR150
g/10 minutes, melting point 84℃, vinyl acetate content 28% by weight)
Partially saponified polyvinyl alcohol (Kuraray product Kuraray Poval,
Prototype, degree of saponification 75 mol%, degree of polymerization 2050, melting point (T
m) 168C) at a rate of 100 parts/hour using a plunger pump (discharge pressure 3 kg/cm3).
G) while continuously supplying pressure at the heating temperature (cylinder temperature, the same applies hereinafter).

) Continuously extruded at 90°C. The resulting extrudate was a milky white homogeneous dispersion, and the average particle size of the resin in the dispersion was less than 1 micron.

This aqueous dispersion (100 parts of resin, 15 parts of partially saponified polyvinyl alcohol, 100 parts of water) was mixed into synthetic paper YUPO FP#1.
It was coated on the back side of No. 10 with a bar coat to a thickness of 5 μm, and left at room temperature for 5 hours to remove moisture, thereby obtaining a label with thermal adhesive properties.

This label was placed on the surface of a polypropylene bottle, which was a material to be adhered (without surface treatment), and was thermally bonded using an electric iron preheated to 100° C. at a sealing pressure of 1 kg/cy.

The adhesive strength was as follows.

Instantaneous 0.1 kg/2 cm After 7 days 0.44 kg/2 cm (Comparative Example 2) Using a hot melt material made of ethylene-vinyl acetate copolymer "Ultracene UE-720" as the adhesive,
A label was attached to the surface of an untreated polypropylene bottle in the same manner as in Example except that the pot temperature of the labeling machine was 100°C and the transfer roll temperature was 90°C.

Adhesive strength (instantaneous) 0.1kg/2cr 〃 (
7 days later) 0.48kg/2Cm Since the labeling method according to the present invention is as described above, it can be expected to have many excellent advantages, the main ones of which are listed below. .

(1) Since a hot-melt agent that is adhesive at room temperature is used, the melting temperature range is wide and the labeling suitability is high.

(2) Non-water-absorbent or poorly water-absorbent materials (labels and adhered materials), which have conventionally been difficult or unsatisfactory to adhere, can be efficiently and reliably bonded together at low cost.

(3) The desired adhesive viscosity can be achieved by making slight improvements only to the glue pot and transfer roll parts and making it possible to heat the adhesive present there, without making any major improvements to the structure of conventional labeling machines. is obtained.

(4) Pre-treatment of labels and adhesive materials (discharge, flame, acid, etc.)
This eliminates the need for equipment costs and running, which reduces costs, and provides favorable effects in terms of quality such as prevention of distortion, easy selection of antistatic agents, and improvement in adhesive stability. Furthermore, work can be performed more safely than before.

(5) Water-resistant, chemical-resistant, solvent-resistant, etc. labels can be applied; (6) No solvents are used, making it extremely hygienic and less likely to cause pollution; (7) Hot-melt adhesive with 100% active ingredients. Since it utilizes a chemical agent, strong adhesive strength can be expected with a small amount of application, and there is no need for drying.

Claims (1)

[Claims] 1. In a method of pasting a label and a material to be pasted, both of which are non-water-absorbent or poorly water-absorbent, with an adhesive using a continuous automatic labeling machine, an ethylene-vinyl acetate copolymer of 2 to 75% by weight as the adhesive, Urethane prepolymer and α
- Using a hot-melt adhesive made of a pinene-phenol copolymer that is sticky at room temperature,
A method for applying a label, which comprises heating until the viscosity becomes .