JPH03136842A - Metallized paper for label - Google Patents

Abstract

PURPOSE:To improve water resistance, bottle washing properties and recoverability by using water-resistant pure-white roll paper whose wet tensile strength at the time of submersion is a specific value or more as base paper. CONSTITUTION:Water-resistant pure-white roll paper whose wet tensile strength measured according to JIS P-8135 after 4-hr submersion is 0.6kg or more is used as base paper. A clay coat layer 2 and an anchor coat layer 3 for developing the metal gloss of a metallized layer are provided on the base paper 1 and the metallized layer 4 is provided thereon. If necessary, a top coat layer 5 is further provided in order to improve the protective of the metallized layer and the adhesion of printing ink.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to metallized paper for labels.

[Conventional technology]

In general, the base material for label paper attached to glass bottle containers for beer, Western liquor, sake, soy sauce, soft drinks, etc. is paper such as high-quality paper or coated paper, or plastic film such as polypropylene or cellophane, or the above-mentioned paper or Plastic film laminated with metal foil, especially aluminum foil laminated paper, is often used. Labels using aluminum foil are preferred because they give a sense of luxury, coolness, and cleanliness due to the metallic luster and color tone of aluminum.

This aluminum foil laminated paper for labels is usually printed in 5 to 6 colors, and then an alkali easily soluble adhesive is applied to the back side (non-metal vapor deposited side) and attached to glass bottles. When collecting and reusing bottles, the collected bottles are treated in a warm alkaline solution to dissolve the alkaline-ready adhesive and remove labels.

However, in the bottle washing process, labels using aluminum foil laminated paper generate a large amount of hydrogen gas due to the reaction between the aluminum foil and the alkaline solution, which poses problems such as the risk of explosion and the negative impact on the working environment. It has become. In addition, since the aluminum foil undergoes plastic deformation, the surface is easily scratched, and there are other problems such as poor workability during printing.

On the other hand, aluminum vapor-deposited paper is commonly used aluminum M (
Because it is extremely thin at 0.02 to 0.06 μm (thickness 6 to 20 μm), less hydrogen gas is generated, and the characteristics of the base material (paper, etc.) can be utilized during printing, improving workability. Very good. In addition, in view of the recent rise in the price of metal aluminum and the need to save resources, labels for washing bottles are increasingly made of the above-mentioned paper or plastic film coated with metal, particularly paper coated with aluminum.

[Problem that the invention seeks to solve]

The basic properties required of metal-metalized paper for washing bottle labels are that the label does not peel off, wrinkle, or bleed when the bottle is cooled in the refrigerator or in cold water, and that it can be collected and washed after use. When bottled, the label must be peeled off from the bottle within a predetermined time using a warm alkaline solution, and the peeled label must not be shattered by the cleaning alkaline solution.

In order to obtain such characteristics, it is necessary to minimize the dimensional change of the base paper when it is immersed in water, to allow the alkaline cleaning solution to penetrate through the paper surface appropriately so that peeling and cleaning can be easily performed, and to ensure that the peeled label does not break into pieces. First, it needs to have excellent tensile strength when submerged in water so that it can be easily recovered.

However, with general high-quality paper, J, TAPPI No. 27
The water immersion elongation measured according to method B is 3 to 5% in the horizontal direction.
This causes large wrinkles and blemishes, which is a problem. There is also paper (pure white roll paper) that undergoes constraint drying using a Yankee paper machine to reduce dimensional changes when submerged in water, but this alone is not sufficient.

In other words, when these papers are used as base paper, labels can be peeled off relatively easily during the bottle washing process, but because their tensile strength is weak when submerged in water, the peeled labels can be shattered by alkaline liquid. This makes it difficult to collect the labels.

On the other hand, there have been proposals to use a plastic film or synthetic paper as the base material, or to provide a polyethylene film layer on the surface of the base material (Japanese Utility Model Publication No. 155276/1983). Although there is almost no problem with dimensional changes during water immersion and recovery of peeled labels, it is not preferable in the bottle washing process because warm alkaline liquid cannot penetrate through the paper surface and it takes a long time to dissolve the adhesive.

The purpose of the present invention is to solve the problem of labels attached to bottles that do not peel off, wrinkle, or clump during cooling, and that the labels are easily removed when washing the bottles, and that the peeled labels break into pieces. The goal is to solve the problem.

[Means for solving problems]

Therefore, the inventors developed an aluminum vapor-deposited label that does not peel off, wrinkle, or blemish on the aluminum vapor-deposited labels attached to the bottles while they are cooling, allows the bottle washing process to be completed in a short time, and makes it easy to collect peeled labels. As a result of studies on metallized paper, the present invention was completed.

That is, the present invention provides JISP 81 after being immersed in water for 4 hours.
By using water-resistant pure white roll paper having a wet tensile strength of 0.6 kg or more as a base paper as measured in accordance with No. 35, the desired metal-deposited paper for labels can be obtained.

Generally, the wet tensile strength of paper is greater in the vertical direction than in the horizontal direction, but in the present invention, it is necessary to use paper that has a tensile strength of at least 0.6 kg in the horizontal direction when submerged in water. . If the weight is less than 0.6 kg, the label will shatter in a bottle washing machine, making it difficult to remove label pieces from the washing liquid.

The water-resistant pure white roll paper of the present invention can be produced by adding a wet abrasive enhancer together with internal chemicals during papermaking using a Yankee paper machine, and performing constrained drying to reduce dimensional changes when submerged in water. It also has improved wet tensile strength.

The wet paper strength enhancer added to the base paper of the present invention includes:
Examples include cationic modified urea resin, urea-formaldehyde resin, melamine-formaldehyde resin, polyethyleneimine, epoxidized polyamide resin, cationic modified polyacrylamide, and methylolated polyacrylamide. These wet paper strength enhancers are preferably added in an amount of 0.5 to 4.0% based on the bulb solid content. 0.
If it is less than 5%, the wet tensile strength becomes weak and no effect is observed. If it is added in excess of 4.0%, the paper machine and equipment become heavily soiled, which is a problem in production.

When making base paper, commonly used internal chemicals such as acidic sizing agents such as rosin emulsion sizing agents and petroleum resin sizing agents, alkyl ketene dimers and alkenyl succinic anhydrides are dispersed in water using cationized starch and emulsifiers. It is okay to add fixing agents such as sulfuric acid, fillers such as clay talc and calcium carbonate, and paper strength agents such as polyacrylamide, starch, and carboxymethyl cellulose to the reactive neutral sizing agent. do not have.

In order to increase the gloss and smoothness of the surface of the paper, a clay coat layer consisting mainly of clay and adhesive is provided and supercalendered.

Pigments used in the clay coating layer of the present invention include plate-like fine particles such as kaolin clay, sericite clay, thetalite clay, and pyrophyllite clay, irregularly shaped light calcium carbonate fine particles, etc., either alone or in combination. I can do it.

Adhesives include homopolymer emulsions or copolymer emulsions such as styrene butadiene, acrylic esters, methacrylic esters, and vinyl acetate, as well as water-soluble resins such as polyvinyl alcohol, oxidized starch, methyl cellulose, and hydroxyethyl cellulose. I can do it.

The clay coat layer is obtained by applying a paint containing the above-mentioned pigment and adhesive, but if the blending ratio of the adhesive becomes high, water resistance and wet strength will improve, but bottle washability will decrease, which is not preferable. Usually pigment/adhesive = 90/10 to 60/4
It is desirable to use a blend of 0.

Conventional coating methods such as air knife method, Meyer bar method, blade method, and reverse roll method can be used for coating.

After coating one side of the base paper so that the coating weight after drying is 5 to 25 g/m', the surface is smoothed using a super calender, machine calender, gloss calender, etc. to achieve the required smoothness and gloss. Get degree.

In order for the vapor-deposited paper to exhibit sufficient gloss, it is desirable that the clay coat layer has a Bekk smoothness of 1000 seconds or more and a gloss level of 50% or more.

The resin used in the undercoat layer of the present invention has the following properties:
An organic solvent-soluble resin is desirable, and a resin that can be easily dissolved in a warm alkaline solution (caustic soda aqueous solution) after coating and drying is preferred. Specifically, phenolic resin, melamine resin, urea resin, phthalic acid resin, silicon resin, vinyl acetate resin, vinyl chloride resin, acrylic resin, polycarbonate resin, boa acetal resin, polyester resin,
Resins such as nitrocellulose resins, urethane resins, ionomer resins, and polyolefin resins, or their resin components, are copolymerized with organic acids such as maleic acid and phthalic acid to appropriately modify them so that they are easily alkali-soluble. It is obtained by coating a resin or a combination of these resins so that the coating amount after drying is 0.5 to 5 g/g. If the coating amount of the anchor coat layer is less than 0.5 g/m'', the glossiness of the deposited layer will be low, and if it exceeds 5 g/m'', bottle washability will deteriorate.

As the coating method for the anchor coat layer, the same coating method as the clay coat layer can be used, and since the amount of coating is small, the gravure roll method can also be used.

As the metal vapor deposition layer, metals such as aluminum, gold, silver, and zinc can be used, but aluminum is preferable from the viewpoint of cost and appearance. The amount of aluminum deposited is preferably 0.01 to 0.07 μm in thickness.

The top coat layer is provided to prevent a decrease in printability and gloss due to oxidation of the vapor deposited layer, and the same resin as that for the anchor coat layer can be used. As for the coating method, coating can be performed using a general method similar to the anchor coat layer.

The present invention will be explained in detail below with reference to the drawings.

In Fig. 1, a clay coat layer 2 is placed on a base paper 1 made of water-resistant pure white roll paper to give a metallic luster to the vapor-deposited layer.
Then, an anchor coat layer 3 is provided, and a metal vapor deposition layer 4 is provided thereon. Furthermore, if necessary, the metallized metal-deposited paper for labels of the present invention can be constructed by providing a top-coat layer 5 in order to protect the vapor-deposited layer and improve adhesion of printing ink.

Examples will be described below, but the present invention is not limited thereto.

(Example 1) 60 parts by weight of bleached hardwood kraft pulp (480 cc of P1 Canadian freeness in LB), 4 parts by weight of bleached softwood kraft pulp (480 cc of P1 Canadian freeness in NB)
For 08B, 1.0 parts of rosin sizing agent (Arayo Kagaku ■
) and 2.0 parts of sulfuric acid, and a cationic modified urea resin (Neelamine P-1500,
1.2 parts (manufactured by Mitsui Toatsu Co., Ltd.) was added, and paper with a basis weight of 50 g/m' was made using a Yankee paper machine. As a clay coat layer on the glossy surface of the obtained paper, 85 parts of kaolin clay (Hydrogloss-90, manufactured by Huber) and styrene-butadiene copolymer latex (JSR-0617, solid content 48
%, made by Japan Synthetic Rubber ■) and 106 parts of water, was applied with a blade coater to a coating weight of 15 g/m'', and then subjected to super calendering to reduce the smoothness of the coated surface to 2. It was set to 500 seconds.

Furthermore, modified vinyl acetate resin (
Coated amount of 2.0 g of Cohonyl P) l-50M (solid ffi content: 50%, manufactured by Nippon Gohsei) using a gravure coater.
/ m”. After depositing aluminum to a thickness of 0.05 μm using a vacuum evaporator,
The vinyl acetate resin used for the anchor coat layer was coated so that the coated amount after drying was 0.5 g/m'' to obtain metallized paper for labels.

After performing predetermined printing and overprint face processing as a beer label, it was attached to a bottle using a label adhesive. The water resistance of the label when it was cured for one week at room temperature and then immersed in cold water at 10°C for 5 days, and when the beer bottle was washed in a bottle washing machine filled with 4% caustic soda solution heated to 70°C. The bottle quality was evaluated and the results are shown in Table 1.

(Examples 2 to 3) In Example 1, the amount of cationic urea-modified resin added was
Labels were created in the same manner as in Example 1, except that the amount was 0.8 parts (Example 2) or 2.0 parts (Example 3). Table 1 shows the evaluation results of the paper-made base paper and the obtained label.

(Examples 4 to 5) In Example 1, 1.0 part of melamine-formaldehyde resin (Sumirezu Resin 607, manufactured by Sumima Kagaku Kogyo ■) was added as a wet paper strength enhancer.Example 4) Also, cationic modified special Polyamide resin (violet resin 650
, manufactured by Sumima Kagaku Kogyo ■) was added (Example 5).
) A label was created in exactly the same manner as in Example 1 except for the following. Table 1 shows the evaluation results for the paper-made base paper and the obtained label.

(Example 6) 70 parts of hardwood bleached kraft pulp (P1 Canadian Freeness 530cc in LB), softwood bleached kraft pulp (
NBKP, Canadian Freeness 530cc) 30!
To B were added 061 parts of alkyl ketene dimer, 1.2 parts of cationized starch, 15 parts of calcium carbonate, 0.5 parts of sulfuric acid, and a cation-modified special polyamide resin (Sumirezu Resin 650, manufactured by Sumima Kagaku Kogyo ■). Water-resistant pure white roll paper with a basis weight of 50 g/m'' was made using a Yankee paper making machine.

In the same manner as in Example 1, a clay coat layer was applied, a supercalender treatment, an anchor layer was applied, an aluminum vapor deposition, and a top coat layer was applied to obtain a vapor-deposited paper. Table 1 shows the characteristics of the base paper and its quality when used as a beer label.

(Examples 7 to 8) In Example-6, the amount of the cation-modified special polyamide wet paper strength enhancer was changed from 0.8 parts (Example?) to 2.5 parts (
A label was produced in the same manner as in Example 6, except for Example 8). The evaluation results for the base paper and labels are shown in Table 1.

(Example 9) A label was created in exactly the same manner as in Example 6, except that 2.0 parts of dialdehyde starch (Caldas, manufactured by Nippon Carlit Aji) was used as the wet paper strength enhancer. The evaluation results are shown in Table 1.

(Comparative Examples 1 and 2) Except for not adding the wet paper strength agent in Example 1 at all (Comparative Example 1) and adding 0 or 3 parts (Comparative Example 2),
A label was created in exactly the same manner as in Example 1. Table 1 shows the quality of the base paper produced and the label obtained.

(Comparative Example 3.4) Exactly the same as Example 0 and Example 6, except that in Example 6, no wet paper strength agent was added (Comparative Example 3), and 0 or 3 parts were added (Comparative Example 4). I created a label. The evaluation results are shown in Table 1.

Each test in Table 1 was conducted according to the following method.

・Wet tensile strength: Conducted according to JIS P 8135 r "Wet tensile strength test method for paper and paperboard". The test piece was immersed in distilled water for 4 hours.

- Underwater elongation J, according to TAPPI paper valve test method Nα27 "Water elongation test method for paper and paperboard" B method.

・Wrinkle caused by flooding The diameter of the sample metallized paper is measured in the horizontal direction.

It was cut into an oval label with a minor axis of 9 cm in the vertical direction, the back side (non-evaporated side) was coated with casein-based glue that was easily soluble in alkali, and the label was attached to a 633i beer bottle. After curing at room temperature for one week, wrinkles occurring on the label surface were observed when immersed in cold water at 10° C. for 5 days.

○ No wrinkles △ Slight wrinkles (lower limit of use) X large wrinkles (unusable) ・Bottle washability After attaching the label, cure at room temperature for one week.

The bottles were washed at 70° C. in a bottle washing machine filled with a 4% caustic soda aqueous solution, and the time until the labels peeled off was measured.

The evaluation was given as "X" if the label peeled off within 5 minutes or "X" if it took more than 0.50 minutes.

・Label recovery After the bottle washability test, the recovery of the separated labels was evaluated.

○ Can be collected with a strainer Labels that come off during bottle washing are easier to collect,
It is possible to provide vapor-deposited paper for labels.

[Brief explanation of the drawing]

FIG. 1 shows a partial sectional view of the metallized paper for labels of the present invention.

Claims (1)

[Claims] Metal-deposited paper for labels, in which a clay coat layer, an anchor coat layer, a metal-deposited layer, and, if necessary, a top coat layer are sequentially provided on one side of a base paper, has a wet tensile strength when immersed in water measured according to JISP8135 of 0. A metallized paper for labels, characterized in that a water-resistant pure white roll paper weighing 6 kg or more is used as a base paper.