JPH0465599A - Aluminum deposited paper - Google Patents

Abstract

PURPOSE:To obtain the subject deposited paper suitable for labeling paper, fire-wrapping paper or cake, etc., having excellent adhesiveness of synthetic resin coating with treating a rear face so as a spontaneous polarization voltage value on the surface of a deposited layer after superposing to be a specific value. CONSTITUTION:A rear face side of base paper such as coated paper provided a coated layer on raw paper of machine pulp, etc., is coated with preferably 1-10wt.% aqueous solution of an alkaline material such as caustic soda preferably in an amount of 3-20g/m<2> and aluminum is deposited on a front face side, then wound or superposed to afford the aimed deposited paper having spontaneous polarization voltage value in an amount of from 0 to -1,100mV (to calomel electrode) on the surface of the aluminum-deposited layer.

Description

Detailed Description of the Invention "Industrial Application Field" The present invention relates to aluminum vapor-deposited paper used for beer bottles, packaging paper (for cigarettes), etc., and particularly relates to aluminum vapor-deposited paper that is stored in a rolled state. This invention relates to aluminum vapor-deposited paper that has been improved so that the synthetic resin and the vapor-deposited layer exhibit good adhesion when a synthetic resin overcoat is applied to the paper.

"Prior Art" Aluminum metallized paper is widely used for label paper for alcohol, beer, soft drinks, etc., packaging paper, packaging paper for confectionery, and the like. There are two types of manufacturing methods for aluminum vapor-deposited paper used for such purposes: a direct method and a transfer method. The direct method is a method in which a resin is undercoated on base paper or a base paper coated with an aqueous coating composition (hereinafter simply referred to as "base paper"), and the resin is vapor-deposited thereon. . On the other hand, the transfer method is a method in which a release layer is formed on a plastic film, aluminum is vapor-deposited thereon, and then the film is bonded to a base paper via an adhesive to transfer the vapor-deposited layer to the base paper.

The surface of the aluminum layer obtained by the direct method or the transfer method (excluding cases where the release layer also serves as a protective layer) is generally coated with a resin to protect the vapor deposition surface. Originally, the surface of the aluminum layer immediately after vapor deposition is chemically active and has good adhesion to resin coating treatment. However, in both the direct method and the transfer method, the vapor-deposited paper is stored in a rolled state before being coated with resin, and in such cases, the surface of the aluminum vapor-deposited layer deteriorates over time. It will no longer exhibit proper adhesion. This phenomenon is thought to be due to the fact that when the surface of the aluminum layer comes into face-to-face contact with the back surface of the vapor-deposited paper, that is, the back surface of the base paper, contaminants are transferred from the back surface of the vapor-deposited paper to the surface of the aluminum layer and contaminate the surface. Therefore, a method to prevent the transfer of contaminants by coating the back side of vapor-deposited paper with PVA resin to form a barrier layer was proposed (Japanese Patent Laid-Open No. 56-14019
7) Treatment to reduce contamination on the surface of the aluminum layer by using base paper containing a specific sizing agent
-124693) etc. have been proposed. however,
These methods cannot sufficiently prevent the transfer of contaminants to the surface of the active aluminum deposited layer, and there is a strong need for aluminum deposited paper with significantly improved adhesion of overcoating resins.

``Problems to be Solved by the Inventionj'' The present invention solves the problem of significantly reducing the adhesion to synthetic resin that occurs when synthetic resin coating is applied to the surface of aluminum vapor-deposited paper stored in a rolled or stacked state. The purpose of the present invention is to provide an improved aluminum vapor-deposited paper.

"Means for Solving the Problems" The present invention provides an aluminum vapor-deposited paper in which an aluminum vapor-deposited layer is provided on a base paper, and the natural polarization potential value of the surface of the aluminum vapor-deposited layer measured by the following method is 0 to 0.
This is an aluminum vapor-deposited paper characterized by using a base paper whose back surface has been treated so as to have a voltage in the range of -1100 mV (vs. calomel electrode).

"Measurement method of natural polarization potential value" The surface of the aluminum evaporated layer formed on the polyester film under the same conditions as when forming it on the base paper and the back surface of the aluminum vapor-deposited layer were stacked facing each other at 50℃. In the atmosphere,
After being left under a pressure of 50 g/cm'' for 3 hours, 0.1M phosphate buffer (pH
7,0), the potential was measured using an aluminum vapor deposited layer as the working electrode, a calomel electrode as the standard electrode, and a platinum electrode as the counter electrode, and the value was measured 60 seconds after the start of measurement.

"Function" In the direct method or the transfer method, after the aluminum vapor deposited layer is provided on the base paper, the surface of the aluminum vapor deposited layer is left for a long time in a rolled or stacked state, and the surface of the aluminum vapor deposited layer has poor adhesion with the overcoating resin. It has already been mentioned that there is a phenomenon in which the However, when aluminum is vapor-deposited on a polyester film or the like, even if the film is left in a wound state for a long time, the above-mentioned significant decrease in adhesiveness is not observed.

Based on this phenomenon, the present inventors focused on the fact that the surface of the aluminum vapor-deposited layer and the back surface of the base paper, which were stored in a rolled or stacked state, were in face-to-face contact under pressure.
Vapor-deposit aluminum on a polyester film (the vapor-deposition conditions are the same as when vapor-depositing on the target base paper, and the same applies below when providing a vapor-deposited layer on the film), and apply it to the surface after vapor-deposition. 50 minutes with nothing in contact, (b) base paper, and (c) polyester film in contact with each other.
As a result of evaluating the adhesion of the aluminum layer surface to the overcoating resin after applying a pressure of 50g/Cl1lz for 3 hours in an atmosphere of (b) When the base paper was brought into contact with the base paper, a significant decrease in adhesion was observed. As a result, it was found that by employing this method, it was possible to evaluate the adhesion between the aluminum evaporated surface and the overcoating resin, which was left in the rolled state.

Based on these findings, the inventors of the present invention have conducted intensive research and examination on the surface characteristics of various base papers and aluminum vapor-deposited layers. As a result, the changes in the natural polarization potential of the aluminum vapor-deposited layer that comes into contact with the base paper during winding. It was found that there is a significant relationship with the decrease in resin adhesion caused by the condition. That is, the natural polarization potential value of the surface of the vapor deposited layer measured after pressing the aluminum vapor deposited layer and the back surface of the base paper under specific conditions is 0 to -11.
We have discovered that by using a base paper whose back side has been treated to have a voltage within the range of 0.00 V (vs. calomel electrode), it is possible to significantly improve the decrease in adhesion with the overcoating resin, and have completed the present invention. It is something.

The natural polarization potential value is a unique value that differs depending on various metals, and reflects changes in the surface state due to deterioration of the metal surface due to oxidation or corrosion, or adhesion of gas, oil, etc. Therefore, when the natural polarization potential value of the surface of the aluminum vapor deposited layer in contact with the back surface of the base paper subjected to various treatments is evaluated against the natural polarization potential value of the surface of the active aluminum vapor deposition layer immediately after vapor deposition, changes in the surface state can be detected. I can know. Therefore,
By appropriately treating the back surface of the base paper that comes into contact with the surface of the aluminum vapor-deposited layer, the adhesion between the surface of the aluminum vapor-deposited layer and the overcoating resin layer can be improved.

The reason why such an excellent effect can be obtained by performing a specific backside treatment is that the backside treatment eliminates contaminants from the surface of the aluminum vapor deposited layer, or that the substances contained in the treatment solution are removed. This is thought to be because it adheres to the surface of the aluminum vapor-deposited layer and prevents contaminants from adhering to the base paper.

Incidentally, the natural polarization potential value is 0 to -1100V (vs,
If the treatment is outside the scope of the calomel electrode), the aluminum deposited layer will be severely contaminated, and as a result, the adhesion of the overcoating resin cannot be improved.

The measurement conditions for spontaneous polarization potential were as follows: 0.1 M phosphate buffer (pH 7.0
), an aluminum vapor-deposited layer for evaluation (deposited on a polyester film) was used as the working electrode, a calomel electrode was used as the standard electrode, and a platinum electrode was used as the counter electrode. In addition, considering the time required for the voltage to stabilize, the value 60 seconds after the start of the measurement was defined as the natural polarization potential value.

In the present invention, the natural polarization potential value of the surface of the aluminum vapor deposited layer after overlapping is 0 to -1100 V (vs.
, calomel electrode), preferably 800 to -11
It is important to process the back side so that it becomes 00V. Therefore, the treatment method for the back side of the base paper is not particularly limited as long as the natural polarization potential value satisfies the above-mentioned conditions. are more preferably used, and at least one of these is used.
It is sufficient to make an aqueous solution with a concentration of about 1 to 10% by weight using at least 1 type of pigment, and coat it on the back side at 3 to 20 g/m''.Additionally, if necessary, a small amount of inorganic pigment or organic pigment may be added to the processing solution. In the present invention, the purpose can be achieved by treating only the back side of the base paper, but it can also be added to the front side of the base paper (i.e., the side on which the vapor deposition layer is to be provided). Similar processing may be performed.

As the base paper used in the present invention, a base paper or a coated paper in which a coating layer containing a pigment and an adhesive as main components is provided on a base paper can be used as appropriate. In addition, such base paper generally includes high-quality paper, various mechanical pulps (BCTMP, CTMP, SOP,
RGP, etc.), DIP, etc. are used as medium-quality paper or base paper made from neutral paper, and the base paper is about 30 to 100 g/m", but there are no particular limitations on these, and the paper making method Also, there are no particular limitations.

In the direct method, an undercoat layer and an aluminum vapor deposition layer are sequentially formed on the base paper treated in this way. In the transfer method, an aluminum layer deposited on a plastic film is transferred onto a base paper provided with an undercoat layer.

The undercoat layer is provided for the purpose of imparting smoothness to the paper so that the aluminum vapor-deposited layer provided thereon has excellent metallic luster, and to increase the adhesive strength between the vapor-deposited layer and the base paper. Such an undercoat layer is a layer containing synthetic resin as a main component, and the synthetic resins used are broadly classified into solvent-based, aqueous-based, and non-solvent-based. -Solvent-based products are used for boat fishing because of their superior quality. Examples of specific resins include acrylic resin, acrylic resin,
Examples include vinyl resins, cellulose resins, urethane resins, and polyester resins.

In addition, various resins may be appropriately modified to be easily alkali-soluble and used in an aqueous system. As for the coating method, coating is performed using a commonly used coating machine such as a roll coater, reverse coater, gravure coater, cast coater, or injected coater.

In the present invention, the amount of aluminum deposited is preferably about 0.01 to 0.1 μm in thickness from the viewpoint of appearance and cost.

Furthermore, on the aluminum vapor deposition layer, oxidation of the metal vapor deposition surface,
An overcoat layer is provided to prevent contamination and to enhance suitability for post-processing such as printing. The overcoat layer is also formed mainly from a synthetic resin, but the same resin as the undercoat layer is appropriately selected and used depending on the purpose, and the coating method is not particularly limited as in the case of the undercoat layer.

"Example" The present invention will be described in more detail with reference to Examples below, but it is of course not limited to these.

In addition, "parts" and "U%" in the examples indicate "parts by weight" and "% by weight," respectively, unless otherwise specified.

[Method for evaluating adhesion of overcoating resin 1] The back side of the treated base paper was brought into face-to-face contact with the surface of the aluminum layer immediately after being vapor-deposited on the polyester film, sealed with a plastic bag, and a load of 50 "gets" was applied. 3
I left it for a while. Next, apply acrylic resin (trade name: Nialumi-Nku W) to the aluminum surface.

(manufactured by Dainichiseika Co., Ltd.) at 1.5 g/m" and
After drying at ℃ for 60 seconds, red printing ink (TOKAS
HIKISOCHEMICAL INDtlSTRY
Co, LT mouth, SD Soot - Deluxe 50 Red B) was printed (manufactured by Mei Seisakusho), and the state of peeling of the overcoating resin was visually determined.

○: Not peeled off at all ×: Peeled off [Overcoating resin adhesion evaluation method 2] A commercially available cellophane tape was attached to the aluminum vapor-deposited paper after the overcoat was applied, and the state of peeling of the overcoating resin was observed when it was peeled off. Judgment was made visually.

○: Not peeled off at all ×: Peeled off Example 1 A paper stock prepared by adding 1.5 parts of rosin size, 5 parts of talc, and 3 parts of sulfuric acid to a bulb mixture of 60 parts of bleached NKP and 40 parts of bleached LKP was dried in a Yankee dryer. The paper was made and dried using a paper machine using a chisel to obtain a base paper with a basis weight of 50 g/m''.

Separately, 100 parts of kaolin (product name: UW-90゜EMC
A pigment slurry having a solid content concentration of 70% was prepared using 0.2 parts of sodium hexametaphosphate (manufactured by Co., Ltd.) and 0.2 parts of sodium hexametaphosphate using a Coles disperser. Oxidized starch (product name: Ace A,
Manufactured by Oji Cornstarch Co., Ltd.) 3 parts (solid content), styrene,
15 parts (solid content) of butadiene copolymer latex was added, and water was further added to prepare a coating liquid with a solid content concentration of 60%.

This coating liquid was coated on the smooth side of the base paper using an off-hand blade coater and dried so that the coated amount after drying was 20 g/m2. Next, 15 g/m2 of 1% sodium bicarbonate aqueous solution was applied to the back side using two kiss roll coaters, and the paper was dried in an air foil dryer to obtain a single-sided coated paper with a paper moisture content of 6.5%. Obtained. Next, smoothing treatment was performed using a supercalender to obtain a base paper for aluminum deposition. Using this base paper, the natural polarization potential value and the adhesion of the overcoating resin were evaluated by [Evaluation Method 1]. Furthermore, an undercoat layer was formed by coating an acrylic resin on this base paper using a gravure coater so that the coated amount after drying was 4 gets, and aluminum was coated on the undercoat layer using a vacuum evaporator. The aluminum vapor-deposited paper was vapor-deposited to a thickness of .05 μ-〇, and after -8 μm, an acrylic overcoat resin was applied to create rolled aluminum vapor-deposited paper. [
Evaluation method 2] was used for evaluation, and the evaluation results are shown in Table 1.

Example 2 Base paper and aluminum vapor-deposited paper were obtained in the same manner as in Example 1, except that the IJium 1% aqueous solution was changed to a 1.5% sodium carbonate aqueous solution, and the evaluation results were It is shown in Table-1.

Example 3 Add 1% aqueous solution of sodium bicarbonate to 1% caustic soda for back surface treatment.
A base paper was obtained in the same manner as in Example 1 except that the solution was changed to a % aqueous solution. Using this base paper, the natural polarization potential value and the adhesion of the overcoating resin were evaluated by [Evaluation Method 1].

Separately, a release agent was applied to a polyester carrier film by gravure coating, and aluminum was vapor-deposited to a thickness of 0.05 μm on the coated surface. The vapor-deposited surface is bonded to the base paper obtained above via a urethane adhesive, and after aging, the carrier film is separated.
- An acrylic overcoat resin was applied to the grain and the paper was rolled up to create aluminum vapor-deposited paper. The adhesion of the overcoating of this vapor-deposited paper was evaluated using [Evaluation Method 2], and the evaluation results are shown in Table 1.

Comparative Example 1 Base paper and aluminum vapor-deposited paper were obtained in the same manner as in Example 1, except that the back side was not treated, and the evaluation results of these are shown in the table.
Shown in 1.

Comparative Example 2 A 1% aqueous solution of sodium bicarbonate for back surface treatment was mixed with polyvinyl alcohol (trade name: PVA-105, manufactured by Kuraray Co., Ltd.) 5
Base paper and aluminum vapor-deposited paper were obtained in the same manner as in Example 1 except that the aqueous solution was changed to % aqueous solution.
Shown in 1.

"Effect" As is clear from Table 1, the aluminum vapor-deposited paper of the present invention has excellent adhesion between the aluminum-deposited surface and the overcoating resin even when left in the rolled state. It was paper.

Table-1

Claims (1)

[Claims] In an aluminum vapor-deposited paper having an aluminum vapor-deposited layer provided on a base paper, the spontaneous polarization potential value of the surface of the aluminum vapor-deposited layer measured by the following method is 0 to -1100.
An aluminum vapor-deposited paper characterized by using a base paper whose back surface has been treated so as to have a voltage range of mV (vs. calomel electrode). "Method for measuring natural polarization potential value" The surface of the aluminum evaporated layer formed on the polyester film under the same conditions as when forming it on the base paper and the back surface of the base paper which has been back-treated are placed facing each other and placed in an atmosphere of 50°C. During,
After being left under a pressure of 50 g/cm^2 for 3 hours, 0.1M phosphate buffer (pH
7.0), the potential was measured using an aluminum vapor deposited layer as the working electrode, a calomel electrode as the standard electrode, and a platinum electrode as the counter electrode, and the value was measured 60 seconds after the start of the measurement.