JPH0415110B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of a heat-sensitive color adhesive label and its manufacturing method, and more specifically, the present invention relates to the structure of a heat-sensitive color adhesive label and its manufacturing method. The present invention relates to the structure of a heat-sensitive color adhesive label that is provided with a release layer and has excellent plasticizer resistance. In this case, the present invention relates to a product and a manufacturing method characterized in that a silicone resin cured by electron beams or ultraviolet rays is used for the release layer, or an ethylene-α-olefin copolymer is used.

Recently, label printers using a thermal printing method have been widely used, especially in the retail industry such as supermarkets, and the demand for thermal coloring adhesive labels is also rapidly increasing.

This heat-sensitive color-forming adhesive label has a heat-sensitive color-forming layer provided on the printed image of the support, and can easily form a desired character image by bringing it into contact with the thermal head of a printing device. This system not only allows large quantities of price tag labels to be easily printed in retail businesses such as supermarkets, but also has the advantage of allowing the content of character images to be changed freely and without making noise.

Conventionally, in this type of heat-sensitive color adhesive label, a release paper was separately prepared and used in combination to protect the surface of the adhesive layer. In this case, the release paper is peeled off from the label body after the heat-sensitive color adhesive label is printed with a label printer, is rolled up separately, and is disposed of when the roll of label material is used up. be. However, the following problems arise due to the use of this release paper. That is, since it is necessary to include a mechanism for peeling off the release paper and winding up the label after printing on the heat-sensitive coloring adhesive label using a label printer, the structure of the machine becomes complicated and large.

There is a complication in that the user must dispose of the used release paper. Furthermore, the release paper is usually coated with silicone resin, making it slippery and difficult to handle.

Since a release paper is also used, the amount of adhesive labels loaded into the label printer per roll is reduced, which naturally increases the number of loading operations.

The purpose of release paper is only to protect the adhesive layer of the label; it has no other use. By combining such release paper with the label body, The associated manufacturing costs are very high.

In view of the above-mentioned current situation, the inventors of the present invention have conducted extensive studies on the structure of heat-sensitive coloring adhesive labels, and have found that:
The idea was different from that of the past, and they came to invent a heat-sensitive coloring adhesive label with a completely new structure that does not require a release paper, and a method for manufacturing the same.

In other words, in a typical heat-sensitive coloring adhesive label, a heat-sensitive coloring layer is provided on a support, and a barrier layer, an adhesive layer, and a release layer are added on top of the heat-sensitive coloring layer in order to prevent plasticizers from migrating into the plastic film used for product packaging. Generally, paper is provided, but in the present invention, in addition to the conventional label consisting of a support, a heat-sensitive coloring layer, a barrier layer, and an adhesive layer, a release paper is further provided. By eliminating the use of release paper for the body, the above-mentioned problems (-) were solved all at once.

In addition, the release layer includes UV-curable silicone resin,
Electron beam curable silicone resin or ethylene
It is characterized by using an α-olefin copolymer as a component.

Each layer of the thermosensitive color adhesive label according to the present invention will be explained in detail below.

Paper or a paper-like material is used as the support for the adhesive label. Suitably, this paper or paper-like material has enough strength to withstand several coatings, finishes, and processing, is relatively dense, smooth, and has good dimensional stability. Examples of this type of paper or paper-like material include general high-quality paper, medium-quality paper with a low GP content, and synthetic paper. In the case of paper, it is particularly desirable that the surface of the paper has been subjected to some degree of sealing treatment, such as surface sizing. Of course, paper such as glassine paper can also be used. The basis weight of the paper is preferably about 40 to 100 g/m ² .

The thermosensitive coloring layer provided on the surface side of the support consists of a colorless or light-colored leuco dye, a phenolic compound necessary for coloring, and a binder.
Sensitizers and other auxiliary agents can be included, but
A specific example is shown below.

1 Leuco dye (a) Triphenylmethane dye 3,3-bis(P-dimethylaminophenyl)-phthalide 3,3-bis(P-dimethylaminophenyl)-6-dimethylaminophthalide (also known as Crystal Bio 3,3-bis(P-dimethylaminophenyl)-6-dimethylaminophthalide 3,3-bis(P-dimethylaminophenyl)-6-chlorophthalide 3,3-bis(P-dibutylamino (phenyl) phthalide (also known as malachite green lactone) (b) Fluoran dye 3-dimethylamino-6-methoxyfluoran 3-dimethylamino-6-methyl-7-chlorofluoran 3-dimethylamino-5-methyl-7 -dibenzylaminofluoran 3-diethylamino-7-chlorofluoran 3-diethylamino-7-methoxyfluoran 3-diethylamino-7-methylaminofluoran 3-diethylamino-7-dibenzylaminofluoran 3-diethylamino-7 -(N-methylanilino)fluoran 3-diethylamino-7-orthochloroaminofluoran 3-diethylamino-7,8benzofluoran 3-diethylamino-6-methyl-7-chlorofluoran 3-diethylamino-6-methyl- 7-anilinofluorane 3-diethylamino-6-methyl-7-P-
Butylanilinofluoran 3-diethylamino-5-methyl-7-dibenzylaminofluoran 3-morpholino-5,6 benzofluoran 3-ethyl-6-methyl-7-anilinofluoran 2-anilino-6- Diethylaminofluorane 3-(N-methyl-N-cyclohexylamino)-6-methyl-7-anilinofluorane (c) Phenothiazine-based benzoyl leucomethylene blue 2,2 dimethyl leucomethylene blue P Anisoyl leucomethylene blue N Pivalyl leuco Methylene blue (d) Rhodamine lactam type N-phenylrhodamine β-lactam Arrhodamine β-saltone (e) Spiropyran type benzo-β-naphthospiropyran 1,3,3-trimethyl-6'-chlor-8'-
Methoxy-indolinobenzospiropyran 2 Phenolic compound The phenolic compound used in the present invention is one that liquefies or vaporizes at room temperature or above and reacts with a color-forming dye to develop a color. For example, 4,4'-isopropylidene diphenol ( Bisphenol A) 4,4'-isopropylidene bis(2-chlorophenol) 4,4'-isopropylidene bis(2-methylphenol) 4,4'-isopropylidene bis(2-tert-butylphenol) 4, 4'-sec butylidene diphenol 4,4'-cyclohexylidene diphenol 4-tert-butylphenol 4-tert-octylphenol 4-tert-octyl caracol 4-phenylphenol (P-phenylphenol) 4-hydroxydiphenol Enoxide 2,2'-Dihydroxydiphenol α Naphthol β Naphthol Methyl-4-hydroxybenzoate Benzyl-4-hydroxybenzoate Ethyl-4-hydroxybenzoate Propyl-4-hydroxybenzoate 4-Hydroxy-acetophenol Novolac type phenolic resin Examples include halogenated novolak type phenolic resins and other phenolic polymers.

3 Binder Polyvinyl alcohol Starch or modified products and derivatives thereof Methyl cellulose Hydroxyethyl cellulose Carboxymethyl cellulose Gum arabic Gelatin Casein Polyvinyl pyrrolidone Polyacrylamide Polyacrylate Styrene/maleic anhydride copolymer Isobutylene/Maleic anhydride copolymer Styrene/Butadiene Copolymer polyvinyl acetate polyacrylate ester 4 White pigment talc, clay, silica, titanium oxide, urea formalin resin 5 Other auxiliary agents Various waxes Higher fatty acid metal salts Higher fatty acid amide Dispersant Wetting agent Antifoaming agent Coating for heat-sensitive coloring layer The amount of work is 2 to 20 in terms of solid content.
g/m ² , particularly in the range from 5 to 10 g/m ² .

The barrier layer facilitates the application of the release layer and functions to protect the thermosensitive coloring layer against migration of plasticizers and the like. It is suitable to use various film-forming water-soluble polymer substances for this layer, such as polyvinyl alcohol, carboxymethyl cellulose,
Methylcellulose, hydroxyethylcellulose, polyacrylamide, starch, gelatin,
Examples include polyvinylpyrrolidone and the like, or a mixture of two or more thereof. The coating amount is 0.5 to 10 g/m ² in terms of solid content, especially 1 to 5 g/m ²
is suitable. When drying after coating, it is important to be careful not to induce coloration in the heat-sensitive coloring layer. A release layer is provided on top of the barrier layer. The application of the release agent layer is an essential requirement for the present invention, and as mentioned above, it completely protects the heat-sensitive coloring layer together with the barrier layer, and in the rolled state, it comes into contact with the adhesive layer to protect it and release paper. This eliminated the use of Silicone resins are generally used to form release layers, but silicone resins must be thermally cured at a high temperature of 100°C or higher after coating. However, since a heat-sensitive coloring layer is already provided in the lower layer, it is impossible to carry out heat curing at the above-mentioned high temperature.

In general, thermosensitive color recording paper develops color at temperatures above 80°C, forming black or blue images. When forming a release layer on a heat-sensitive coloring layer, it is a matter of course that the condition must be met that it can be processed at a low temperature of 80°C or less.

The inventors of the present invention have conducted extensive research into resins that can form a release layer while satisfying the above conditions, and have found that the following resins are optimal. That is, ultraviolet curable silicone resins that can be cured at low temperatures, electron beam curable silicone resins, and even ethylene-curable silicone resins.
This is α-olefin copolymer.

By using these types of resins, the problems of color development in the heat-sensitive coloring layer during manufacture and decolorization due to the plasticizer in the plastic film during use can be skillfully avoided, and the peeling layer can be formed extremely effectively at low temperatures. can be provided.

More specifically, as the ultraviolet curable silicone resin or electron beam curable silicone resin used, for example, a radical addition polymerization reaction or a dimerization reaction initiated by ultraviolet ray or electron beam irradiation was used.

(1) Mixed composition of organopolysiloxane containing mercapto group and organopolysiloxane containing vinyl group (2) Organopolysiloxane composition containing acrylic group, methacrylic group or cinnamoyl group (3) Organopolysiloxane composition containing maleimide group or phenylmaleimide group Polysiloxane composition (4) Mixed composition of organopolysiloxane containing azide group and organopolysiloxane containing vinyl group (5) Organopolysiloxane composition containing thioacrylic group, thiomethacrylic group or thiocinnamoyl group (6) Acrylamide group, Examples include organopolysiloxane compositions containing methacrylamide groups or cinnamoylamide groups, and mixtures of epoxy group-containing organopolysiloxanes using ultraviolet-initiated cationic polymerization and diazonium Lewis acid salts as photodegradable initiators. Compositions and the like can also be used.

For UV curing, a curing initiator is required.
As the curing initiator, known benzoin alkyl ether and its derivatives, acetophenone and its derivatives, benzophenone and its derivatives, thioxanthone and its derivatives, etc. are used.

In the case of electron beam curing, no curing initiator is required. By using the silicone resin and the curing technique described above, a release layer can be formed in an atmosphere of 80° C. or lower.

For the release layer, resins other than silicone having release properties as described above can be selected. Examples of this type of resin include ethylene-α/olefin copolymer.

Examples of α-olefins include (1) propylene (2) α-butylene (3) α-pentene (4) α-hexene (5) α-heptene (6) and α-octene.
It may be one in which more than one species is copolymerized with ethylene. The resin is dissolved in a solvent or used in the form of an aqueous emulsion.

The coating amount of each resin constituting the release layer is preferably 0.5 to 10 g/m ² in terms of solid content, particularly 1 to 5 g/m ²
is suitable. If it exceeds 10 g/m ² , the thermal conductivity will deteriorate when printing on adhesive labels, which is not preferable.

An adhesive is applied to the back side of the adhesive label support, and an undercoat layer is provided in order to prevent the adhesive from penetrating into the support and to fully exhibit adhesive curing. As with the barrier layer, it is preferable to use a film-forming water-soluble polymeric substance as a component of the undercoat layer. Namely, polyvinyl alcohol, carboxymethylcellulose, methylcellulose, hydroxyethylcellulose,
One or a mixture of two or more of polyacrylamide, starch, gelatin, polyvinylpyrrolidone, etc. can be used. The coating amount is 0.5 to 10 g/m ² in terms of solid content, especially 1 to 5 g/m 2 .
As in the case of barrier layer coating, it is preferable that m ² be used, and care must be taken not to cause color development in the heat-sensitive coloring layer during drying after coating.

Even if an adhesive is applied to the undercoat layer, an adhesive layer is provided. As the pressure-sensitive adhesive, a known composition containing a cohesive polymer compound such as an acrylic ester as a main ingredient, to which a tackifier, a stabilizer, a fluidity regulator, etc. may be added can be used. The coating amount of adhesive is 5 to 40 g/m ² in terms of solid content, especially 10 to 25
A range of g/m ² is optimal.

Each layer constituting the thermosensitive color adhesive label of the present invention has been described above.

As a coating method, coating can be performed using a conventional roll, bar, blade, air knife, etc. After coating, the original fabric is finished into a small roll having a predetermined width and length in the finishing and processing steps.

The heat-sensitive coloring adhesive label of the present invention thus obtained can easily produce homogeneous and clear prints and images using a label printer. In addition, by coating the release layer, the protection of the heat-sensitive coloring layer by the barrier layer is further strengthened, so there is no problem such as loss of printing due to transfer of plasticizer from the packaging film that comes in contact with it, and the printing The durability of the surface has been greatly improved. Furthermore, since the release layer also serves to protect the adhesive layer and no release paper is used, it can be said that the structure of the adhesive product is more rational.

Next, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto.

Example 1 Dispersion A and Dispersion B were prepared by mixing and pulverizing the following components for 24 hours using a ball mill.

Dispersion A 3-diethylamino-7-orthochloroanilinofluorane 1 part by weight Polyvinyl alcohol (20% aqueous solution) 5 Water 44 Dispersion B Bisphenol A 4 parts by weight Calcium carbonate 3 Stearamide 1 Polyvinyl alcohol 20 % aqueous solution 10〃 Water 32〃 Prepare a coating liquid for the heat-sensitive coloring layer by mixing liquids A and B, apply it on one side of high-quality paper (basis weight 50g/m ² ), dry it, and apply it in terms of solid content. A heat-sensitive coloring layer with a work amount of 7 g/m ² was formed. A barrier layer and an undercoat layer were provided on the front and back sides of this heat-sensitive coloring paper so that a coating amount of a 5% aqueous solution of polyvinyl alcohol was 2 g/m ² in terms of solid content.

Next, 100 weight parts of solvent-free ultraviolet curable silicone (composed of 30 parts by weight of organopolysiloxane containing 1.5 mol% mercapto groups and 70 parts by weight of organopolysiloxane containing 1.5 mol% vinyl groups: manufactured by Shin-Etsu Chemical Co., Ltd.) is placed on the barrier layer. 3 parts by weight of acetophenone as a curing initiator was added to the coating amount of 1 g/ ^m2.
Apply the coating and use the UV curing device Uniquyure UV.
-4000 (manufactured by Ushio Inc.), ultraviolet rays were irradiated for 1 second at an input of 160 W/cm to form a release layer. No color development was observed in the heat-sensitive coating layer. Acrylic emulsion adhesive (manufactured by Saiden Chemical Co., Ltd.) is applied on the undercoat layer provided on the opposite side of the heat-sensitive coating layer.
was applied in a coating amount of 20 g/m ² in terms of solid content, dried and rolled up. The obtained heat-sensitive adhesive label was tested for color development, and the results were as follows: 150°C, 2Kg/cm ² ,
Under the printing conditions of 1 second, the color density D = 1.3 is sufficiently high, and even if this product is placed in close contact with a soft polyvinyl chloride film and left at 40°C for 15 hours, the density D is 1.2.
There was only a slight decrease. The adhesiveness as a label and the releasability between the adhesive layer and the release layer were also good.

Example 2 A heat-sensitive coloring layer, a barrier layer, and an undercoat layer were formed in the same manner as in Example 1.

Electro-curable acrylic modified silicone resin ZWO-149 (manufactured by Goldschmidt) is placed on the barrier layer.
The coating amount was 1 g/m ² in terms of solid content, and the coating was applied using an electron beam curing device, Electron Curtain CB-.
Cure was performed using 150 (manufactured by ESI) at an irradiation dose of 3 Mrad. No color development was observed in the heat-sensitive color development layer.

An adhesive layer was formed in the same manner as in Example 1.

The obtained heat-sensitive color adhesive label was tested in the same manner as in Example 1, but the color density D = 1.31 and the image density D = 1.22 after being brought into close contact with the soft PVC film.
It was good. The adhesiveness as an adhesive label and the releasability between the adhesive layer and the release layer were also good.

Example 3 A heat-sensitive coloring layer, an obstruction layer, and an undercoat layer were formed in the same manner as in Example 1.

An aqueous emulsion of ethylene-propylene copolymer (manufactured by Mitsui Petrochemicals) was coated on the barrier layer at a coating weight of 5 g/m ² in terms of solid content, dried and rolled up.

An adhesive layer was formed in the same manner as in Example 1.

The obtained heat-sensitive colored adhesive label was tested in the same manner as in Example 1, but the color density D = 1.30 and the image density D = 1.23 after being brought into close contact with the soft PVC film.
It was good.

The adhesiveness as an adhesive label and the releasability between the adhesive layer and the release layer were also good.

Claims (1)

[Claims] 1. A heat-sensitive color former layer, a barrier layer, and a release layer are sequentially provided on the front side of the support, and an adhesive layer is provided on the back side with or without an undercoat layer. 1. A heat-sensitive color-forming adhesive label, characterized in that the main component of the release layer is an ultraviolet curable or electron beam-curable silicone resin, and is cured. 2. In a heat-sensitive color-forming adhesive label in which a heat-sensitive color former layer, a barrier layer, and a release layer are sequentially arranged on the front side of the support, and an adhesive layer is provided on the back side with or without an undercoat layer. , a heat-sensitive coloring adhesive label characterized in that the main component of the release layer is an ethylene-α/olefin copolymer. 3 2 to 20 g/m ² in terms of solid content on the surface side of the support
0.5 to 10 g/m ² in terms of heat-sensitive coloring agent layer and solid content
Apply and dry a barrier layer, and then apply a release layer whose main component is an ultraviolet curable or electron beam curable silicone resin or an ethylene-α-olefin copolymer at a rate of 0.5 to 10 g/m ² in terms of solid content. Production of a heat-sensitive color adhesive label characterized by drying and curing and coating an adhesive layer of 5 to 40 g/m ² in terms of solid content on the back side of a support with or without an undercoat layer. Law.