JPS6071286A - Copying sheet for thermal recording - Google Patents

Abstract

PURPOSE:To obtain the titled sheet favorable in adhesion between a vapor-deposited metallic layer and a thermal color forming layer and suitable for high- speed recording, by a method wherein a thermal color forming layer is provided on a base (provided with a vapor-deposited metallic layer) through an anchor coat layer, and a heat-fusible ink layer is provided on the other side of the base. CONSTITUTION:The vapor-deposited metallic layer having a thickness of about 200-2,000Angstrom is provided on one side of a paper having a thickness of 10-30mum or a resin film having a thickness of about 5-20mum. The metal is preferably aluminum. To enhance the adhesion between the metallic layer and the thermal color forming layer, an anchor coat forming agent such as casein and a copolymer of isobutylene and maleic acid anhydride is applied to the metallic layer in an amount of 1-10g/m<2> to provide the anchor coat layer. Thereafter, the thermal color forming layer comprising a color forming substance, a phenolic compound and a binder as main constituents is provided. The heat-fusible ink layer comprising a coloring agent, a binder, an oil or the like is provided on the side opposite to the thermal color forming layer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal recording copy sheet suitable for high-speed recording.

Conventionally, as a thermal recording copying sheet for producing multiple sheets of records, there has been known a thermal recording paper with a thickness of 35 to 5 Qpan with a heat-melting ink layer provided on the back side. By overlapping the copy sheet and plain paper and performing thermal recording, color recording of the heat-sensitive layer and transfer recording to the plain paper are performed simultaneously.

However, since recording using conventional thermal recording copy sheets requires a large amount of heat, it is not practical for high-speed printers because it causes blurring, uneven printing, etc., and it is not possible to obtain a sufficient transferred image. Ta.

Therefore, it is necessary to make the support thinner in order to increase the thermal conductivity and achieve faster recording and lower energy consumption. If the support is simply made thinner, the thermal conductivity is improved, but the heat-melting ink on the back side can be seen through the support, reducing the whiteness of the heat-sensitive coloring layer and making the image difficult to see.

In order to eliminate these drawbacks, it has been proposed to make the support thinner and at the same time provide a vapor deposited layer of metal such as aluminum on one or both sides of the support. , (Unexamined Japanese Patent Publication No. 1987-
(No. 148689, Japanese Unexamined Patent Publication No. 58-78793) However, this type of thermal recording copy sheet has low sensitivity,
Although the whiteness etc. are improved, the adhesion between the metal vapor deposited layer and the heat-sensitive coloring layer is poor, and the copy sheet may be cut with a cutter.
There is a drawback that the thermosensitive coloring layer peels off from the metal vapor deposited layer when the thermosensitive coloring layer is folded or written on with a ballpoint pen or the like.

The inventors of the present invention have conducted extensive research to overcome this drawback, and have now accomplished the present invention.

That is, the present invention provides a thermal recording copying sheet (K) characterized in that a metal vapor deposited layer, an anchor coat layer, and a thermosensitive coloring layer are sequentially provided on one side of paper or a resin film, and a heat-melting ink layer is provided on the opposite side. It is related to

In the present invention, an anchor coating agent having good adhesion to both the metal vapor deposition layer and the thermosensitive coloring layer is applied to the anchor coating layer. Examples of the anchor coating agent include casein and an isobutylene anhydrous Vine copolymer, among which casein is particularly preferred. On the other hand, polyvinyl alcohol, for example, has poor adhesion to the metal vapor deposited layer and is not preferred. The anchor coating agent is applied to the surface of the metal vapor deposited layer Fci to 10 f/l♂.

The paper used in the present invention has a thickness of 10 to 30 .mu.tn, and for example, a relatively high-density paper such as capacitor paper or glassine paper is used. In addition, the resin film used in the present invention includes those with a relatively high melting point such as polyester film, polyimide film, and polypropylene film with a thickness of about 5 to 20 μm, but from the viewpoint of transfer sensitivity and physical strength, resin with a thickness of 8 to 15 μm Films are preferred.

The metal vapor deposition layer functions as a hiding layer for the heat-fusible ink, and is provided to a thickness of about 200 to 200 C)A.

Aluminum is preferred as the metal used.

The heat-sensitive coloring layer of the present invention can be one used in general heat-sensitive recording paper, and its composition is mainly composed of a colorless or light-colored coloring substance, a phenolic compound, and a binder. It will look like this:

a) Colorless to light-colored color-forming substances Generally called leuco compounds, they are substances that develop color by reacting with acidic substances, such as triphenylmethane type and triphenylmethane-phthalide type.

Examples include various leuco bodies such as fluoran series, leuco auramine series, and spiropyran series.

b) Phenolic compound A substance that is solid at room temperature, softens or melts when heated, and develops a color when it comes into contact with the above-mentioned leuco compound, such as 4-
Tertiary butylphenol, 4-phenylphenol, 4-hydroxydiphenoxide, α-naphthol, β
-naphthol, methyl-4-hydroxybenzoate,
4'-hydroxyacetophenone, 4-tertiaryoctylcatechol, 2.21-dihydroquine diphenyl, 2.2/-methylenebis(4-chlorophenol),
4j4'-isopropylidenediphenol, 4,4'-
Examples include secondary butylidene diphenol, 4,4'-isopropylidene bis(2-methylphenol), 44'-isopropylidene bis(2,6 dimethylphenol) roseoxybenzoate, and the like.

C) Binder Water-soluble binders are mainly used as binders.

During dispersion, the two-component coloring agent is coated on each component so that no color develops when both components are mixed.

Examples of water-soluble binders include casein, polyvinyl alcohol, modified starch, gelatin, carboxymethyl cellulose, hydroxyethyl cellulose, polyvinylpyrrolidone, and polyacrylamide.

For 9F use with these water-soluble binders, latexes such as styrene-butadiene copolymer θ, poly611 vinyl, and polyacrylic ester can also be used.

d) Other additives The composition of the heat-sensitive recording layer may contain other additives, such as various waxes, fatty acid amides, etc. to improve recording properties.
Fat chain metals, various white pigments to improve the whiteness and writability of the recording paper surface, and water resistance agents to improve water resistance can also be added.

The heat-melting ink layer used in the present invention can be used as is for general thermal recording copying sheets, including carbon black as a coloring agent, an organic pigment, an inorganic pigment, and a synthetic or natural wax as a binder. , other dyes,
Heat-melt oil or the like or dissolve it in a solvent to make hot-melt ink.

The thermal recording copy sheet of the present invention has good printing performance at high speed,
It is suitable for use in high-speed printers because the heat-sensitive coloring layer has a high degree of whiteness and does not peel off or fall off.

The present invention will be explained in more detail below with reference to Examples.

Example 1 On a polyethylene terephthalate film having a thickness of 12 pm, a layer of aluminum was vacuum-deposited at a thickness of about 100 mm, and then about 3 f/- of casein dissolved in ammonia was coated thereon to form an anchor coat layer. Next, apply the following heat-sensitive coloring paint on top of the casein anchor layer at approximately 79/n? Coated. Furthermore, about 59 Ad of heat-melting ink was coated on the opposite side to the heat-sensitive whitening layer to obtain a heat-recording copying sheet.

0 Heat-sensitive color layer paint A liquid black color dye 1s-205 (manufactured by Yamada Chemical) 5 parts stearic acid amide 8 parts calcium carbonate 27 parts polyacrylic ammonium 20% liquid 3 parts P VA
12% solution 40 parts Water 47 parts Part B Bisphenol A 5 parts Stearin-related zinc 3 parts Calcium 22 parts Polyacrylic ammonium 20% solution 3 parts PVA 1
2% solution 40 parts Water 47 parts After dispersing solutions A and B with a sand grinder, AtL
130 parts 70 parts of a 12% PVA aqueous solution is added to 130 parts of liquid B and mixed to form a paint.

Comparative Example 1.2゜ Comparative Example 1 without the casein anchor layer of Example 1,
Comparative Example 2 uses polyvinyl alcohol instead of casein.

The adhesion of the thermal recording copy sheets obtained in the above Examples and Comparative Examples to the aluminum vapor-deposited M was tested using a seven-rope peel test. The results are shown in Table 1.

Table 1 Note) Seven Ropeel Test A commercially available adhesive tape (Scotch Mending Tape) was attached to the heat-sensitive coloring layer, and when it was removed, the degree of peeling of the heat-sensitive coloring layer was visually observed.

As is clear from the table, the thermal recording copying sheet of the present invention has no fear of peeling of the thermal coloring layer. In addition to the high degree of whiteness on the surface of the coloring layer, this thermal recording copying sheet also exhibited very good printing performance in a high-speed printing test. On the other hand, the thermal recording copying sheet of the comparative example had a weak adhesive force between the thermosensitive color forming layer and the metal vapor deposited layer, and was unusable.

Patent applicant Honshu Paper Co., Ltd.

Claims (1)

[Claims] A thermal device characterized in that a metal vapor deposition layer, an anchor coat layer of casein or isobutylene maleic anhydride copolymer, and a heat-sensitive coloring layer are sequentially provided on one side of a paper or resin film, and a heat-melting ink layer is provided on the opposite side. Copy sheet for records.