JPH06171201A - Recording sheet for heat sensitive stencil printing - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a recording sheet for heat-sensitive stencil printing having improved ink absorbency and writing aptitude. In a recording sheet in which an ink absorption layer containing a pigment and a binder as main components is provided on a support, the oil absorption based on JISK5101 when one kind or two or more kinds are mixed in the ink absorption layer Volume is 45 ml /
A pigment of 100 g or more and 120 ml / 100 g or less was included.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording sheet excellent in ink absorption used for heat-sensitive stencil printing.

[0002]

2. Description of the Related Art In recent years, heat-sensitive stencil printing has become widespread as a simple printing method suitable not only for business use but also for personal use. This printing method uses a stencil sheet that can be melted by heat to remove the heated portion.When this stencil sheet is overlapped with a document and irradiated with light, the heat generated in the image area of the document is used. The basic principle is to conduct printing to the stencil sheet and to remove the portion corresponding to the image portion from the stencil sheet, by extruding ink through this removed portion. A fine printed image can be provided on the stencil sheet by constructing the above-mentioned stencil sheet with, for example, a laminate of a fine mesh-like porous support and a heat-meltable polymer. This heat sensitive stencil printing is widely used for printing New Year's cards and the like because it is easy to perform multicolor printing.

As the ink receiving sheet used in this heat-sensitive stencil printing, a medium quality paper such as a postcard manufactured by a public authority is generally used.

[0004]

However, since these conventional receiving sheets have low ink absorbing power, not only uniform printing cannot be performed, but also the ink is poor in dryness and the sheets can be superposed immediately after printing. There was a drawback that I could not. Further, when writing on these receiving sheets with a pencil, a ballpoint pen, a water-based pen, an oil-based pen, a fluorescent pen, etc., there arises a problem in writing aptitude such as bleeding, scraping, slipping, and cissing.

An object of the present invention is to provide a recording sheet which has improved ink absorbability in heat-sensitive stencil printing, which is a drawback of the above-mentioned conventional sheets, and further has improved writing suitability.

[0006]

SUMMARY OF THE INVENTION The present invention comprises:
A recording sheet provided with an ink absorbing layer containing a pigment and a binder as main components, wherein the pigment is JI
JISK5 when a pigment having an oil absorption of 45 ml / 100 g or more and 120 ml / 100 g or less based on SK5101 is used, or when two or more pigments are mixed
Oil absorption based on 101 is 45ml / 100g or more, 12
The above problems are solved all at once by using two or more kinds of pigments of 0 ml / 100 g or less in combination.

The pigments used in the present invention include alumina, magnesium hydroxide, calcium hydroxide, magnesium carbonate, zinc oxide, barium sulfate, silica, calcium carbonate, kaolin, calcined kaolin, diatomaceous earth, talc, titanium oxide, water. Inorganic pigments such as aluminum oxide,
Examples of the organic pigment include urea-formalin resin, styrene-methacrylic acid copolymer, polystyrene resin and amino resin filler. In addition, the general pigment is physically
Inorganic and organic pigments which have been chemically treated so as to have a specific oil absorption amount as described above may also be appropriately used. In this case, the oil absorption of the single pigment or the mixed pigment is 45 ml /
If the amount is less than 100 g, the ink absorbing property of the ink absorbing layer is remarkably lowered, so that the drying of the ink is deteriorated and the recording sheets cannot be superposed after printing. On the contrary, if the oil absorption exceeds 120 ml / 100 g, a pencil, ballpoint pen,
When writing with a water-based pen, oil-based pen, or fluorescent pen,
It causes a marked decrease in writing aptitude such as bleeding, blurring, slippage, and cissing.

The binder used in the ink absorbing layer in the present invention is a completely saponified polyvinyl alcohol having a polymerization degree of 200 to 1900, a partially saponified polyvinyl alcohol, a carboxy modified polyvinyl alcohol, an amide modified polyvinyl alcohol, a sulfonic acid modified polyvinyl alcohol. , Butyral modified polyvinyl alcohol, other modified polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, styrene-maleic anhydride copolymer, styrene-butadiene copolymer, styrene-acrylic acid copolymer, acrylonitrile-butadiene system Copolymers and cellulose derivatives such as ethyl cellulose and acetyl cellulose, polyvinyl chloride, polyvinyl acetate, polyacrylamide, polyacrylic Esters, polyvinyl butyral, polystyrene and copolymers thereof, polyamide resins, silicone resins, petroleum resins, terpene resins, ketone resins, coumarone resins, starch, starch derivatives,
Casein can be exemplified. These polymer substances can be used in the state of being emulsified in water or another medium, and can be used together depending on the required quality.

The blending ratio of the pigment used in the ink absorbing layer is not particularly limited, but it is blended so as to be in the range of 60 to 95% by weight, preferably 70 to 90% by weight based on the total solid content. It is desirable to do. The coating amount is not particularly limited, and is generally 0.5 to 20 g.
/ M ² , preferably about 3 to 6 g / m ² .

Regarding the method of forming the ink absorbing layer,
It can be formed according to a well-known technique, for example, an off-machine coating machine or an on-machine coating machine equipped with various coaters such as an air knife coater, a rod blade coater, a bill blade coater, and a roll coater is appropriately selected and used. It If necessary, smoothing treatment such as super calendaring can be applied.

On the other hand, in the present invention, a heat-sensitive recording layer, an ink ribbon or the like is used on the back surface of the support, which uses a heat-sensitive recording layer or ink ribbon to obtain a recorded image by a heat-melting reaction between a colorless dye (leuco dye) and a color developer such as phenol. A thermal transfer recording layer where a recorded image is obtained by transferring by heating from a head, an ink jet recording layer for recording characters, images, etc. by causing minute droplets of ink to fly and adhere to a recording medium according to various operating principles, Various known recording media such as a pressure sensitive recording layer where a capsule is broken by locally applying pressure such as writing pressure or type pressure, and the color forming dye solution reacts with the color developer to obtain a recorded image. Can be provided. in this way,
By providing a recording layer adapted to various printing methods on the back side, the utility value of this recording sheet is remarkably improved. For example, when it is used as a postcard for New Year's cards etc., the surface is accompanied by a pattern by thermal stencil printing. You can print a message and type the destination and sender as the output of a printer such as a computer or word processor on the back side.

In particular, in the case of providing a heat-sensitive recording layer, in order to avoid the show-through of the image on the surface and the warp (curl) of the recording sheet due to the heat-sensitive stencil printing, the pigment on the back surface An undercoat layer mainly composed of a binder and a binder is provided, and an overcoat layer mainly composed of a pigment and a binder is also provided in order to protect the heat-sensitive recording image, for example, by preventing stains due to ink in the heat-sensitive stencil printing. It is desirable to provide it.

Further, in the present invention, as the support, any sheet material such as paper, synthetic paper, plastic film, non-woven fabric and the like can be used.

[0014]

In the present invention, the reason why the ink absorptivity and the uniformity of the printed image at the time of heat-sensitive stencil printing and the writing aptitude are excellent is considered as follows. By defining the oil absorption amount of the pigment contained in the ink absorbing layer to be 45 ml / 100 g or more, a large ink absorbing power can be obtained, and the drying of the ink can be accelerated accordingly, and even if the recording sheets are superposed immediately after printing. , There is no ink transfer. In addition, since the oil absorption of the pigment is regulated to 120 ml / 100 g or less, it is suitable for writing with a pencil, ballpoint pen, water-based pen, oil-based pen, highlighter pen, etc. It is possible to avoid such phenomena.

[0015]

EXAMPLES The present invention will be described below with reference to examples.
In the description, parts indicate parts by weight.

[Example 1] (Formation of ink absorption layer) Calcium carbonate (trade name: Callite SA Shiraishi Kogyo, oil absorption 50 ml / 100 g) 10 parts 10% aqueous polyvinyl alcohol solution 2.5 parts The above composition was mixed. An ink absorbing layer coating liquid was obtained. These coating liquids were applied and dried on the surface of a medium-quality paper having a basis weight of 150 g / m ² so that the applied amount after drying was 6 g / m ^2, and the ink receiving sheet had a smoothness of 700 to 700 on a super calendar.
It processed so that it might become 800 seconds. (Formation of backside undercoat layer) Calcined kaolin 100 parts Styrene / butadiene copolymer latex (solid content: 48%) 11 parts 10% polyvinyl alcohol aqueous solution 5 parts The above composition is mixed to prepare a coating solution for the backside undercoat layer. Got This coating solution was applied and dried on the back surface of the ink receiving sheet obtained above so that the coating amount after drying was 5.0 g / m ² . (Formation of Thermosensitive Recording Layer on Back Side) Liquid A (Developer Dispersion Liquid) 4-Hydroxy-4′-isopropoxydiphenylsulfone 6.0 parts 10% polyvinyl alcohol aqueous solution 18.8 parts Water 11.2 parts Liquid B (dye) Dispersion) 3-N-n-dibutylamino-6-methyl-7-anilinofluorane 2.0 parts 10% polyvinyl alcohol aqueous solution 4.6 parts water 2.6 parts C solution (sensitizer dispersion) 4 -Biphenyl p-tolyl ether 4.0 parts 10% aqueous polyvinyl alcohol solution 5.0 parts water 3.0 parts Each liquid of the above composition was ground with a sand grinder to an average particle size of 1 micron. Next, the dispersion liquids were mixed at the following ratios to prepare coating liquids. Liquid A 36.0 parts Liquid B 9.2 parts Liquid C 12.0 parts Calcium carbonate 50% dispersion liquid 12.0 parts The coating amount after drying the above thermal recording layer coating liquid on the undercoat layer obtained above is The coating was dried so as to be 5.0 g / m ^2, and a thermosensitive recording layer on the back surface was formed. (Formation of Backside Overcoat Layer) Calcium carbonate 3.0 parts 10% polyvinyl alcohol aqueous solution 3.5 parts The above composition was mixed to obtain an overcoat layer coating liquid. These coating solutions were applied onto the heat-sensitive recording layer obtained above so that the coating amount after drying was 2.0 g / m ² and dried, and treated with a super calender so that the smoothness was 700 to 800 seconds. .

[Example 2] (Formation of ink absorbing layer) Calcium carbonate (trade name: Callite KT Shiraishi Kogyo, oil absorption 60 ml / 100 g) 10 parts 10% aqueous polyvinyl alcohol solution 2.5 parts The above composition was mixed. An ink absorbing layer coating liquid was obtained. These coating liquids were applied and dried on the surface of a medium-quality paper having a basis weight of 150 g / m ² so that the applied amount after drying was 6 g / m ^2, and the ink receiving sheet had a smoothness of 700 to 700 on a super calendar.
It processed so that it might become 800 seconds. An undercoat layer, a thermosensitive recording layer and an overcoat layer were provided on the back surface of the ink receiving sheet in the same manner as in Example 1 and calendering was performed.

[Example 3] (Formation of ink absorbing layer) 1: 1 mixture of silicon dioxide and aluminum hydroxide Oil absorption amount 100 ml / 100 g 10 parts (trade name: Nipsil E-743 manufactured by Nippon Silica) (trade name: Heidi Light H-42 (Showa Denko) 10% polyvinyl alcohol aqueous solution 2.5 parts The above composition was mixed to obtain an ink absorbing layer coating liquid. These coating liquids were applied and dried on the surface of a medium-quality paper having a basis weight of 150 g / m ² so that the applied amount after drying was 6 g / m ^2, and the ink receiving sheet had a smoothness of 700 to 700 on a super calendar.
It processed so that it might become 800 seconds. An undercoat layer, a thermosensitive recording layer and an overcoat layer were provided on the back surface of the ink receiving sheet in the same manner as in Example 1 and calendering was performed.

[Comparative Example 1] (Formation of ink absorbing layer) Aluminum hydroxide (trade name: Hydilite H-42 manufactured by Showa Denko, oil absorption amount 30 ml / 100 g) 10 parts 10% aqueous polyvinyl alcohol solution 2.5 parts The above composition The materials were mixed to obtain an ink absorbing layer coating liquid. These coating liquids were applied and dried on the surface of a medium-quality paper having a basis weight of 150 g / m ² so that the applied amount after drying was 6 g / m ^2, and the ink receiving sheet had a smoothness of 700 to 700 on a super calendar.
It processed so that it might become 800 seconds. An undercoat layer, a thermosensitive recording layer and an overcoat layer were provided on the back surface of the ink receiving sheet in the same manner as in Example 1 and calendering was performed.

Comparative Example 2 (Formation of Ink Absorbing Layer) Silicon dioxide (trade name: Nipsil E-743, manufactured by Nihon Silica, oil absorption 165 ml / 100 g) 10 parts 10% aqueous polyvinyl alcohol solution 2.5 parts By mixing, an ink absorbing layer coating liquid was obtained. These coating liquids were applied and dried on the surface of a medium-quality paper having a basis weight of 150 g / m ² so that the applied amount after drying was 6 g / m ^2, and the ink receiving sheet had a smoothness of 700 to 700 on a super calendar.
It processed so that it might become 800 seconds. An undercoat layer, a thermosensitive recording layer and an overcoat layer were provided on the back surface of the ink receiving sheet in the same manner as in Example 1 and calendering was performed.

Comparative Example 3 An undercoat layer, a heat-sensitive recording layer and an overcoat layer were provided on the back surface of a medium-quality paper having a basis weight of 150 g / m ² and calendered.

Table 1 shows the results of a quality test conducted on the recording sheets obtained in the above Examples and Comparative Examples.

[0023]

[Table 1]

Note (1) Ink absorptivity: Heat-sensitive stencil-type small plate making machine manufactured by Riso Kagaku Kogyo Co., Ltd., print Gokko, and high mesh ink GREEN manufactured by Riso Kagaku Kogyo Co., Ltd. were used to measure the time required for ink drying. did. ◎… within 5 minutes ○… 5 to 10 minutes △… 10 to 30 minutes ×… 30 minutes or more Note (2) Printing uniformity: Visually check the uniformity of the printing ink of the image printed by the method of (1). Observe, ○: good,
Δ: Slightly inferior, ×: evaluated as defective. Note (3) Writing suitability: bleeding when writing with a pencil, ballpoint pen, water-based pen, highlighter pen, fountain pen, oil-based pen,
Visually observe the degree of scraping, slippage, and repelling, and ○:
Good, Δ: somewhat inferior, ×: evaluated as poor.

[0025]

The effects of the present invention are as follows. (1) In heat-sensitive stencil printing, it is excellent in ink absorption and printed image uniformity. (2) When writing with a pencil, a ballpoint pen, a water-based pen, a fluorescent pen, a fountain pen, an oil-based pen, etc., there is no bleeding, blurring, slipping, cissing, etc., and it is excellent in writing suitability.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] March 24, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

Regarding the method of forming the ink absorbing layer,
It can be formed according to a well-known technique, for example, an off-machine coating machine or an on-machine coating machine equipped with various coaters such as an air knife coater, a rod blade coater, a bill blade coater, and a roll coater is appropriately selected and used. It If necessary, smoothing treatment such as super calendaring can be applied. Inn as above
A heat absorption layer is provided on both the front and back sides of the support to make it sensitive to heat
A recording sheet suitable for stencil printing may be configured.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hidenori Tsukada 1-12-1, Yurakucho, Chiyoda-ku, Tokyo Inside Jujo Paper Co., Ltd. (72) Inventor Koichi Okusawa 2-20-15, Shinbashi, Minato-ku, Tokyo Ideal Science Industry Co., Ltd.

Claims (3)

[Claims] 1. A recording sheet in which an ink absorbing layer containing a pigment and a binder as main components is provided on a support, and the pigment has an oil absorption of 4 according to JISK5101.
A recording sheet for heat-sensitive stencil printing, wherein the recording sheet is 5 ml / 100 g or more and 120 ml / 100 g or less. 2. The pigment is two or more kinds,
Oil absorption of 45 ml / 100 g or more, 120 ml / 100 g based on JISK5101 when mixed with one or more pigments
The recording sheet for heat-sensitive stencil printing according to claim 1, wherein: 3. The heat-sensitive stencil recording sheet according to claim 1, wherein a heat-sensitive recording layer, a thermal transfer recording layer, an ink jet recording layer or a pressure-sensitive recording layer is provided on the back surface of the support. .