JPH06255237A - Heat sensitive recording sheet to which pasting aptitute is imparted - Google Patents

Abstract

PURPOSE:To provide a pressure sensitive recording sheet wherein in the case where a large number of sets are piled upon each other and one side wall is pasted up, pasting is not generated among the sets each, by a method wherein a layer containing a surface active agent and water repellent agent at a specific ratio is provided on at least either one of the rear of a lower sheet or the surface of an upper sheet of the sets each through coating. CONSTITUTION:In a pressure sensitive recording sheet, a large number of sets which are constituted of an upper sheet and lower sheet or the upper sheet at least an intermediate sheet and the lower sheet and use color development reaction of an electron donating colorless coating with an electron accepting developer are piled upon each other and one side wall is pasted. Then a layer containing a surface active agent and water repellent agent so that a ratio of the surface active agent/repellent agent is 0.01-0.30 is provided through coating on at least one of the rear of the lower sheet or the upper sheet (excepting the upper most paper). With this construction, in the case where a large number of sets are piled up with each other and one side wall is coated with paste, pasting is not generated among the sets and the sets each can be stripped off reliaby and easily.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a pressure-sensitive recording sheet provided with sizing aptitude, that is, top paper, and at least 1 if necessary.
Stack a large number of sets consisting of a sheet of middle paper and a lower paper 1
The present invention relates to a pressure-sensitive recording sheet that can reliably and easily peel off each set when a side wall is glued.

[0002]

2. Description of the Related Art A color image is formed by a reaction between an electron-donating or proton-accepting colorless organic compound (hereinafter referred to as a color former) and an electron-accepting or proton-donating compound (hereinafter referred to as a developer). It has been known for a long time, and pressure-sensitive recording sheets, heat-sensitive recording materials and the like have been widely used as concrete applications of this phenomenon. Generally, a pressure-sensitive recording sheet is a combination of an upper leaf paper in which a microcapsule containing a color former is applied to a support such as paper and a lower leaf paper in which a color developer is applied to a support such as paper, paper, etc. The support is composed of a combination of the above-mentioned upper leaf paper and the above-mentioned lower leaf paper, which is coated with microcapsules containing a color-developing agent on one side and coated with a color developer on multiple sides. When the microcapsule layer of the pressure-sensitive recording sheet and the developer layer are arranged so as to be in contact with each other and a writing pressure or a printing pressure is applied, the microcapsule is destroyed, and the color former and the developer inside the capsule are broken. React and develop color,
A color image is formed and recording is performed.

The pressure-sensitive recording sheet is used as a slip of a large number of sheets. In this case, each set is a top sheet, and if necessary, at least one middle sheet and a lower sheet. It is made of paper and one side of each set is glued. In the case of making a large number of such glued sets, each set of a large number of sets is overlapped and glue is applied to one side surface thereof. In this case, since the back surface of the lower leaf paper of each set and the surface of the upper leaf paper of the set located below the lower leaf paper are not generally coated with a binder or the like, there is little glue on this surface and they are easily separated. Since the glue is difficult to seep into the side portions of the surface of the paper sheet having the microcapsule layer and the developer layer, it is possible to take out each set easily by utilizing this phenomenon. However, when the above set glue is applied, the glue may enter between the back surface of the lower leaf paper and the front surface of the upper leaf paper, and glue sticking may occur between the sets to make it difficult to separate each set. In order to solve the problem, it has been proposed to make either of the above surfaces water resistant or water repellent. (JP-A-58-59889, 2-13)
No. 4282).

[0004]

As described above, even when the pressure-sensitive recording sheet is used as a set, color printing or the like is performed on the surface of the upper leaf paper, and a white pigment or the like is used as a binder to improve printability. Along with this, it is provided by applying it to the surface of the upper leaf paper. In this case, for example, the coating liquid contains a surfactant in order to perform coating at high speed and uniformly by curtain coating or the like. However, if the coating layer contains a surfactant, as described above, When a large number of sets are stacked and glue is applied to one side wall, the glue is likely to seep into the edge of the coating layer containing the surfactant, which causes glue sticking between the sets and It's hard to leave. Therefore, as described above, the object of the present invention is to provide a coating layer of a pigment or the like on the upper leaf paper of each set of pressure-sensitive recording sheets, which enables uniform coating at high speed and stacks a large number of sets. It is an object of the present invention to provide a pressure-sensitive recording sheet in which no glue is produced between each set when one side wall is glued.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to achieve the above object, and as a result, when a pigment or the like was applied onto the upper leaf paper of the pressure-sensitive recording sheet, a surfactant was used. The present invention has been accomplished by finding that the above object can be achieved by containing a water repellent in a specific ratio. That is, the present invention utilizes a coloring reaction between an electron-donating colorless dye and an electron-accepting color developer to produce a large number of upper leaf papers, and optionally at least one middle leaf paper and a lower leaf paper. In a pressure-sensitive recording sheet in which sets are stacked and one side wall is glued, a surfactant and a water repellent are provided on at least one side of the lower leaf paper and upper leaf paper (excluding the uppermost one) of each set. The pressure-sensitive recording sheet is characterized in that a layer containing it is applied so that the ratio of the surfactant / water repellent is 0.01 to 0.30. The present invention is particularly effective when the above layers are applied by curtain coating.

The present invention will be described in detail below. Examples of the surfactant used in the present invention include nonionic surfactants such as carboxylic acid salt-based, sulfonate-based, sulfate ester-based, and phosphoric acid ester-based surfactants; cationic surfactants such as quaternary ammonium salts; Amphoteric surfactants such as betaine type and aminocarboxylic acid type; ether type, ether ester type,
Examples thereof include ester type nonionic surfactants; fluorine type surfactants; etc., but are not particularly limited. Examples of the binder used in the present invention include water-soluble polymer compounds such as polyvinyl alcohol, carboxy-modified polyvinyl alcohol, silicon-modified polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, hydroxymethyl cellulose, hydroxypropyl cellulose, epichlorohydrin modified polyamide, and vinyl acetate-acrylamide. Polymer, ethylene-maleic anhydride copolymer, styrene-maleic anhydride copolymer,
Examples include isobutylene maleic salicylic anhydride copolymer, polyacrylic acid, polyacrylamide, methylol modified polyacrylamide, sodium polystyrene sulfonate, sodium alginate, starch, modified starch, casein, gum arabic, and gelatin.

Further, a water-proofing agent can be added to these binders for the purpose of imparting water resistance. Further, water-insoluble polymers such as styrene-butadiene rubber latex, acrylonitrile-butadiene rubber latex, methyl acrylate-butadiene rubber latex, vinyl acetate emulsion and the like can also be used. As the pigment used in the present invention, calcium carbonate, kaolin, calcined kaolin, talc, diatomaceous earth, aluminum hydroxide,
There are magnesium hydroxide, zinc oxide, lithopone, amorphous silica, colloidal silica, calcined stone, silica, barium carbonate, magnesium carbonate, titanium oxide, alumina, barium sulfate and the like. As the water repellent used in the present invention, a general water repellent used for paper coating is used, and examples thereof include wax emulsion, silicone oil, paraffin emulsion, alkyl ketene dimer, styrene-acrylic resin, and metal. Soap, etc. are mentioned. In the present invention, the ratio of the above-mentioned both components in the coating liquid applied to the surface of the top paper, that is, the surfactant / water repellent is 0.01 to
When it is 0.30 (that is, 0.01 / 1 to 0.30 / 1), preferably 0.05 to 0.20, uniform coating can be performed at high speed by curtain coating or the like, and the set glue as described above It has been found that, when a large number of sets are stacked and applied, there can be obtained a pressure-sensitive recording sheet having good adhesiveness without sticking between the sets.

When the amount of the surfactant is larger than the above range,
Adhesion between sets occurs when set glue is applied, especially
This tendency becomes remarkable when it is applied together with the pigment as described above. Further, if the amount of the surfactant is less than the above range, a high speed and uniform coating cannot be performed when coating this layer. In the present invention, as described above, it is particularly effective when a pigment coating layer is provided in order to perform color printing or the like on the surface of the upper sheet of each set. Examples of the pigment used at this time include calcium carbonate, titanium oxide,
Examples include inorganic pigments such as clay and talc. When such a pigment layer is provided, a pigment is added together with the above-mentioned surfactant and water repellent together with a suitable binder, and the pigment is applied onto top paper. As the binder used here, a binder used when applying a color developing agent described later is used. In addition, in the present invention, the above-mentioned surfactant and water repellent may be coated on the layer after the pigment layer is provided, or in the case where the pigment layer is not provided. May also be applied on the top leaf paper, and in some cases, on the back side of each bottom leaf paper. Also, according to the present invention, the front surface of the upper paper and the back surface of the lower paper may be applied. The above layers may be applied by a conventional coating method, for example, an air knife coat, a roll coat, a rade coat, etc., for example, US Pat. No. 3,508,947.
This is particularly effective when applied by curtain coating described in the specifications of Nos. 3,632,374, 3,632,403, etc., and uniform coating can be performed at high speed.

The method for producing microcapsules according to the present invention is described in US Pat.
Method for utilizing coacervation of hydrophilic colloidal sol described in 800,458, British Patent 867,79
No. 7, 950, 443, No. 989, 264, No. 1, 091, 076 and the like, the interfacial polymerization method,
Alternatively, the method described in US Pat. No. 3,103,404 may be used. In the present invention, a synthetic resin-based wall material is preferable as the capsule wall material, and for example, a polyurethane and / or polyurea-based melamine resin-based capsule is preferable. Examples of the color former used in the present invention include triphenylmethanephthalide compounds, fluorane compounds, phenothiazine compounds, indolylphthalide compounds, indolylazaphthalide compounds, leukoauramine compounds, rhodamine lactam compounds. Examples thereof include compounds, triphenylmethane compounds, triazene compounds and spiropyran compounds.

As the hydrophobic liquid used for producing the microcapsules containing these color formers, natural or synthetic oils can be used alone or in combination. Examples of hydrophobic liquids are cottonseed oil, kerosene, paraffin, naphthene oil, alkylated biphenyls, alkylated terfels, chlorinated paraffins, alkylated naphthalenes, diarylalkanes,
Examples thereof include dibasic acid esters such as phthalic acid ester. The number average particle diameter of the microcapsules is preferably 1 to 20 μ, more preferably 2 to 8 μ. Examples of developers that react with the color former in the microcapsules according to the present invention include acid clay, activated clay, attapulgite, zeolites, bentonite, clay substances such as kaolin, metal salts of aromatic carboxylic acids and phenolic resins. To be These developers are applied to a support such as paper together with a binder such as styrene butadiene latex. The microcapsules according to the present invention are coated on the water-resistant support and used in combination with the developer layer as a pressure-sensitive recording sheet as a set as described above.

[0011]

EXAMPLES The present invention will be specifically described below with reference to examples. Example 1 A dispersion containing 300 parts of calcium carbonate, 3 parts of sodium hexametaphosphate and 280 parts of water, 60 parts of SBR latex (as solid content), 24 parts of paraffin wax (as solid content), triethanolamine alkylbenzene sulfonate. 3 parts of salt (as solid content) was added, and water was added so that the solid content concentration was 40% to obtain a coating liquid (I). Coating liquid (II) Coating liquid II was prepared as follows. 5 parts of a partial sodium salt of polyvinylbenzene sulfonic acid (manufactured by National Starte, VERSA, TL500) is dissolved in 95 parts of hot water and then cooled. An aqueous sodium hydroxide solution was added to this to adjust the pH to 4.0. On the other hand, 100 parts of diisopropylnaphthalene in which 3.5% of the compound of the specific example (1) is dissolved is emulsified and dispersed in 100 parts of a 5% aqueous solution of a partial sodium salt of polyvinylbenzenesulfonic acid to obtain a particle size of 4.0 μm. A viscous emulsion was obtained. Separately 6 parts of melamine, 37
60 parts by weight of 11% by weight formaldehyde aqueous solution and 30 parts of water
After heating and stirring at 0 ° C. for 30 minutes, a transparent aqueous solution of the melamine-formaldehyde prepolymer was obtained. This aqueous solution was mixed with the above emulsion. While stirring, the pH was adjusted to 6.0 with a 2M phosphoric acid solution, the liquid temperature was raised to 65 ° C., and stirring was continued for 6 hours. The capsule solution was cooled to room temperature and adjusted to pH 9.0 with an aqueous sodium hydroxide solution. 1 for this dispersion
200 parts of 0% by weight polyvinyl alcohol aqueous solution and 50 degrees of starch particles were added and water was added to prepare a 20% solid temperature solution of the microcapsule dispersion. 40 g / m
On one of the ^two base papers, the coating liquid (I) was added so that the solid content was 10 g / m ²
It is coated and dried by a curtain coating coater so that it is coated, and the coating liquid (II) is coated and dried by a curtain coating coater so that a solid content of 5 g / m ^{2 is} coated on the other surface (I 2) layer and (II) layer were applied at high speed and uniformly, and an electron-donating colorless dye-containing capsule sheet (top paper A) could be obtained.

Coating Liquid (III) Coating Liquid III was prepared as follows. 3,5-bis-α
10 parts of zinc methylbenzylsalicylate was added to 20 parts of 1-isopropylphenyl-2-phenylethane and dissolved. This was mixed with 50 parts of a 2% aqueous solution of polyvinyl alcohol and 0.1 part of a 10% aqueous solution of dodecylbenzenesulfonic acid triethanolamine salt, and emulsified so that the average particle size was 3 μm. Next, a dispersion liquid consisting of 80 parts of calcium carbonate, 20 parts of zinc oxide, 1 part of sodium hexametaphosphate and 200 parts of water was mixed with the above emulsion, and further, as a binder, 100 parts of a 10% PVA aqueous solution and carboxy-modified. 10 parts of SBR latex (solid content was added) was added and water was added so that the solid content concentration became 20% to obtain a coating liquid (A). Next, a dispersion containing 10 parts of the electron-accepting compound, 20 parts of Shilton claim, 60 parts of calcium carbonate, 20 parts of zinc oxide, 1 part of sodium hexametaphosphate and 200 parts of water was used to obtain an average particle size of 3 μm with a sand grinder. Dispersed so that. 10% PV in this dispersion
16 parts of A aqueous solution, 100 parts of 10% PVA aqueous solution, and 10 parts of carboxy-modified SBR latex (solid content)
Was added and water was added so that the solid content concentration became 20% to obtain a coating liquid (B). The coating liquid (A) and the coating liquid (B) were mixed 1: 1 in terms of an electron-accepting compound. While the the base paper 40 g / m ^2, the coating solution (II) solids coating and dried at a curtain coating coater as 5 g / m ² coating, a solid the coating liquid (III) on the other surface When coated and dried with a curtain coating coater so that the amount of 5 g / m ^{2 was} applied, both the (II) layer and the (III) layer could be applied at high speed and uniformly, and the intermediate paper B could be obtained. The coating liquid (III) is applied to one side of 40 g / m ² of the base paper by a curtain coating coater so that the solid content is applied at 5 g / m ² , and the other side is coated with the coating liquid (I). When coated and dried with a curtain coating coater so that the amount of 10 g / m ² can be applied, both the (III) layer and the (I) layer can be applied at high speed and uniformly, and the electron-accepting compound sheet (lower paper C) I was able to get

When the surface tension of the liquid (I) was measured, it was 3
The value was 4 dyne / cm, which was a sufficiently low value. The contact angle of the (I) layer of the upper paper A and the lower paper C is set to Fuji Film Set Glue 65
When measured using No. 6, it was a high value of 90 °. One set of upper paper A, middle paper B, and lower paper C is combined into one set, and 100 sets are stacked,
Part 1 The side wall was glued with Fuji Film Set Glue 656. The sharpness between C and A was the best (it is best not to bond between C and A at all, and this case is referred to as good handling).
The adhesiveness between A and B and between B and C was sufficient.

Comparative Example 1 A coating solution (IV) was obtained in the same manner as the coating solution (I) of Example 1 except that the alkylbenzenesulfonic acid triethanolamine salt of Example 1 was not added.
One of the 40 g / m ² base paper was coated with the coating liquid (IV) so that the solid content was 1
An attempt was made to apply it with a curtain coating coater so that 0 g / m ^{2 was} applied, but the curtain film could not be formed and it could not be applied. The coating liquid (IV) is coated on one side of the base paper of 40 g / m ² by an air knife coater so that the solid content is coated at 10 g / m ² and dried, and the coating liquid (II) is spread on the other side. It was coated with a curtain coating coater so as to be coated at 5 g / m ² and dried to obtain an electron-donating colorless dye-containing capsule sheet (top paper D). The coating liquid (III) is applied to one of the 40 g / m ² base paper by a curtain coating coater so that the solid content is applied to 5 g / m ² , and the coating liquid (IV) is solidified on the other surface. An electron-accepting compound sheet (lower leaf paper E) was obtained by coating and drying with an air knife coater so that the amount of 10 g / m ^{2 was} coated.

When the surface tension of the liquid (IV) was measured, it was 5
The value was as high as 8 dyne / cm. When the contact angle of the (IV) layer of the upper paper D and the lower paper E was measured using Fuji Film Set Adhesive 656, it was a high value of 96 °. One set is a combination of upper sheet D, middle sheet B, and lower sheet E, and one set is 100 pieces.
When the side walls were glued with Fuji Film Set glue 656, the sharpness between D and E was good, and the adhesiveness between D and B and B and E was sufficient.

<Comparative Example 2> The coating liquid (I) of Example 1 was similarly prepared except that the paraffin wax of Example 1 was not added to obtain a coating liquid (V). One of the 40g / m ² base paper,
Apply the coating liquid (V) with a curtain coating coater so that the solid content is applied at 10 g / m ^{2, and} apply the coating liquid (II) to the other surface at the solid content of 5 g / m ^2. When applied and dried with a curtain coating coater, layer (V)
High-speed and uniform coating was possible on both layers (II), and an electron-donating colorless dye-containing capsule sheet (top paper F) could be obtained. While the the base paper 40 g / m ^2, the coating solution (III) solids coating and dried at a curtain coating coater as 5 g / m ² coating, a solid the coating liquid (V) on the other surface When coated and dried with a curtain coating coater so that the amount of 10 g / m ² can be applied, both (III) layer and (V) layer can be applied at high speed and uniformly, and an electron-accepting compound sheet (lower sheet G ) Was able to be obtained.

(V) When the surface tension of the liquid was measured, it was 2
The value was 8 dyne / cm, which was a sufficiently low value. The contact angle of the (V) layer of the upper paper F and the lower paper G is set to Fuji Film Set Glue 65
When measured using No. 6, it was a low value of 0 °.
One set consisting of one upper paper F, one middle paper B, and one lower paper G was stacked, and 100 sets were stacked, and one side wall was glued with Fujifilm set glue 656. It also adhered, and the handling performance was poor. F
The adhesiveness between B and B and G was sufficient. The above results are shown in the following table.

[0018]

[Table 1]

[0019]

As is clear from the above results, according to the present invention, the pigment layer can be uniformly applied at a high speed by curtain coating on the top paper, and when each set is glued, a suitable glue is applied. Is obtained, the pigment-containing layer is glued,
There was no problem that was difficult to remove.

Claims (2)

[Claims] 1. An upper leaf paper and a lower leaf paper, or an upper leaf paper, at least one piece of a middle leaf paper, and a lower leaf, which utilizes a coloring reaction between an electron-donating colorless dye and an electron-accepting color developer. In a pressure-sensitive recording sheet in which a large number of sets of paper are stacked and one side wall is glued, a surfactant and a water repellent are provided on at least one of the back surface of the lower leaf paper and the surface of the upper leaf paper of each set. A pressure-sensitive recording sheet, comprising a coating layer containing a surfactant / water repellent ratio of 0.01 to 0.30. 2. The pressure-sensitive recording sheet according to claim 1, wherein the layer containing a surfactant and a water repellent is applied by a curtain coating method.