JPH1083140A - Inmold label - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inmold label which does not degrade an antistatic function by falling of an antistatic agent layer at the time of molding and using. SOLUTION: After a thermoplastic resin layer 3 is formed on the rear surface of a base material 2, a pattern printed layer 4 is formed on a front surface side, a protective layer 6 is formed on the pattern printed layer 4 via an antistatic characteristic adhesive layer 5 which exhibits both an electrostatic induction preventing function and an adhesive function by interposing therebetween as an intermediate layer. Further, the protective layer 6 at an uppermost surface may be composed of a PET(polyester) film and the antistatic characteristic adhesive layer 5 may be provided between the base material 2 and the printed layer 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a label (in-mold label) which is inserted into a mold at the time of molding a container or the like and is attached simultaneously with injection molding.

[0002]

2. Description of the Related Art An in-mold label in which a pattern is printed on the surface of a base material having a thermoplastic resin layer formed on the back surface. An apparatus provided with a coating layer of an antistatic agent (antistatic agent) or an impregnated film layer is conventionally known. Most of those used as antistatic agents are various surfactants, and these surfactants are applied to the surface of plastic or kneaded into plastic to form a conductive layer on the outermost surface. , Thereby exhibiting antistatic properties.

[0003]

In the conventional in-mold label, since the antistatic agent layer is exposed on the surface, it may be removed by friction or the like during molding or use, and the antistatic function may be deteriorated. In addition, there has been a problem that the antistatic agent is sticky and that slippage during label supply is not good.

Accordingly, it is an object to provide an in-mold label in which the antistatic agent layer is not removed during molding or use and the antistatic function is not deteriorated.

[0005]

SUMMARY OF THE INVENTION According to the present invention, an antistatic adhesive which exhibits both an electrostatic induction preventing function and an adhesive function by being interposed as an intermediate layer is provided between an in-mold label base material and a protective layer. This problem has been solved by interposing. An antistatic adhesive having both an electrostatic induction preventing function and an adhesive function as an intermediate layer is, for example, sold under the trade name of “Bondip” (registered trademark) by Altec Corporation.

[0006] The above antistatic adhesive exhibits both the function of preventing electrostatic induction and the function of bonding by being interposed between the substrate and the protective layer as an intermediate layer. This electrostatic dielectric prevention function is based on an induced antistatic effect (which is known per se), unlike a function based on dissipation / dispersion of static electricity such as an antistatic agent in a conventional in-mold label. When this antistatic adhesive is interposed as an intermediate layer, a depolarizing electric field is generated that generates electric lines of force in the direction opposite to the electric lines of friction due to frictional charging. The lines are canceled, and the lines of electric force no longer appear on the outer surface of the in-mold label, resulting in a phenomenon similar to electrostatic shielding, thereby exhibiting dielectric antistatic performance. Further, the lamination adhesiveness of the in-mold label is improved by the adhesive function of the antistatic adhesive.

In the thus formed in-mold label, since the antistatic adhesive is not exposed on the surface, the label does not come off due to friction or the like at the time of molding or use, so that the electrostatic induction preventing function is not deteriorated. In addition, the antistatic adhesive does not make the slippage during label supply worse.

The antistatic adhesive layer may be provided between the protective layer and the printing layer, or may be provided between the substrate and the printing layer.

[0009]

FIG. 1 shows a layer structure of an in-mold label 1 according to the present invention. This in-mold label 1 is made of an OPP (stretched polypropylene) film, PE
A T (polyester) film, paper, synthetic paper, or the like is used as a base material 2, and a thermoplastic resin layer 3 is formed on the back surface of the base material 2 by coating an EVA (ethylene-vinyl acetate copolymer) emulsion. A pattern printing layer 4 of a urethane-based ink is formed on the surface side of the substrate 2 by gravure printing, and an acrylic polyol-based two-part curable ink is coated on the pattern printing layer 4 via an antistatic adhesive layer 5. In which a protective layer 6 is formed.

The base material 2 needs to have a predetermined thickness in consideration of the rigidity and cost of the label.
For μ and PET, 50 to 75 μ is desirable. In the case of paper, it is preferably 70 to 110 g / cm ² .

The antistatic adhesive layer 5 is formed as an intermediate layer to exhibit both an electrostatic induction preventing function and an adhesive function. For example, "Bondip" (registered trademark) by Altec Co., Ltd. Is applied by a gravure printing method to a thickness of 0.1 to 0.3 μm. There are various types of "bondips".

Table 1 below shows the properties of "bond dip" for dry lamination.

[Table 1]

Table 2 below shows the properties of the "bond dip" for primer coating.

[Table 2]

Hereinafter, the electrostatic induction performance will be described. Generally, electrostatic induction means that when an electrostatic charge is generated on the outer surface of an insulator (dielectric), an opposite charge is generated on the other surface, that is, induction charging. When the space a from + (plus) to-(minus) shown in FIG. 3 is a dielectric, the electric flux lines go from + (plus) to-(minus). A negative (−) charge is generated on the lower surface. When a certain dielectric is inserted into this space a, the surface of the conductor is inductively charged as shown in FIG. At this time, as shown in FIG. 4, electric lines of force in the opposite direction to the electric lines of FIG. 3 are generated in the conductor. This electric field is called an anti-electric field or a depolarizing electric field. The lines of electric force in the opposite direction cancel each other out with the lines of electric force shown in FIG. 3, and the intensity is reduced. This attenuation is related to the electrical conductivity of the conductor and the magnitude of the dielectric constant.In the case of a good conductor such as a metal, it almost completely cancels out the lines of electric force. It does not appear to the outside. This phenomenon is called a static shield. A phenomenon similar to this electrostatic shielding occurs even when the conductivity is not as good as metal and the dielectric constant is not as large as metal. Then, in that case, the induction antistatic performance appears. The basic performance of "Bondip" is based on this principle.

However, the bond strength of "bond dip" may be reduced under high temperature and high humidity. Therefore, in the in-mold label 1, in order to prevent water from permeating from the label edge portion, a “bond dip” layer (antistatic adhesive layer 5) and an ink layer (the pattern printing layer 4 and the protection layer) are provided at the edge portion. The "bond dip" is partially coated so as not to reach the label edge as shown by the dashed line in FIG. 2 so that the interlayer portion with the layer 6) is not exposed. Further, in order to prevent water from penetrating into the “bond dip” layer (antistatic adhesive layer 5) due to a pinhole or the like during printing of the protective layer 6, the protective layer 6 is formed by 6 a and 6 b in FIG. It is printed twice as shown.

The two-part curable ink of the protective layer 6 contains a plasticizer in an amount of 2 to 5% to prevent curling.

The thermoplastic resin layer 3 is added with about 10 to 20% of PE (polyethylene) wax as needed in order to improve the slipperiness at the time of automatically supplying the label. Fine irregularities are provided.

In the in-mold label 1 according to the present invention, the outermost protective layer 6 may be a PET (polyester) film. In this case, the antistatic adhesive layer 5 is composed of the base material 2 and the printing layer 4. Between them. Such an in-mold label 1 is obtained by laminating and bonding a base film coated with a thermoplastic resin on the back surface and a PET film printed with a pattern on the back surface via an antistatic adhesive. The materials and compositions of the base material, the thermoplastic resin, the printing ink, and the antistatic adhesive may be the same as those in the above examples.

[0019]

According to the in-mold label of the present invention,
Since the antistatic adhesive is not exposed on the surface, it is possible to prevent the electrostatic induction preventing function from being deteriorated due to friction or the like during molding or use, and to prevent the slipperiness of the label surface from being deteriorated. .

[Brief description of the drawings]

FIG. 1 is a sectional view showing a layer structure of an in-mold label according to the present invention.

FIG. 2 is a plan view showing a partial coat of an antistatic adhesive layer of the in-mold label of FIG. 1;

FIG. 3 is an explanatory diagram (part 1) of an electrostatic induction prevention performance.

FIG. 4 is an explanatory diagram (part 2) of the electrostatic induction prevention performance.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 In-mold label 2 Base material 3 Thermoplastic resin layer 4 Picture printing layer 5 Antistatic adhesive layer 6 Protective layer

Claims (3)

[Claims] 1. An in-mold label comprising a printed layer formed on the front side of a base material having a thermoplastic resin layer formed on the back surface, and a protective layer formed on the printed layer, wherein the label is interposed as an intermediate layer. An in-mold label, wherein an antistatic adhesive which exhibits both an electrostatic induction preventing function and an adhesive function is provided between the base material and the protective layer. 2. The in-mold label according to claim 1, wherein an antistatic adhesive layer is provided between the protective layer and the printing layer. 3. The in-mold label according to claim 1, wherein an antistatic adhesive layer is provided between the substrate and the printing layer.