JP2000229475A - Pressure-sensitive recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a pressure-sensitive recording material in which the burden to the environment is reduced without sacrificing general performances such as the coloring density, the formation of coloring fouls in processing and others required for the pressure-sensitive recording material and also in the case desensitizing ink layer is formed on a developer layer, a vegetable oil in microcapsules is permeated through a substrate when recording is carried out so that the desenitizing ink layer is protected from being turned into the form of a transparent recorded image. SOLUTION: A pressure-sensitive recording material is provided with a coloring agent layer 20 containing microcapsules 14 wrapping an electron donative coloring agent dissolved in a solvent composed of a vegetable oil and formed on one face of a substrate 10 and a developer layer 16 containing an electron accepting developer formed on the other face of the substrate 10, and a layer composed of a latex binder as a main component is formed between the substrate 10 and the coloring agent layer 20, and the developer 16 is composed of an active clay.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color forming layer containing microcapsules containing a color former and a developer layer containing a color developer, which are brought into contact with each other under pressure to destroy the microcapsules and cause a color forming reaction. A pressure-sensitive recording material.

[0002]

2. Description of the Related Art As a pressure-sensitive recording material, for example, an upper sheet having a color former layer formed on one side of a support, a color former layer formed on one side of a support, and a developer layer on the opposite side. A three-copy non-carbon paper-type recording material is known in which three types of sheets are stacked in this order, ie, a middle sheet on which a colorant layer is formed and a lower sheet on which a developer layer is formed on one side of a support. FIG. 3 schematically shows an example of a non-carbon paper type recording material of a three-sheet copy type. The upper paper 50 in which a color former layer 58 is provided on one side of a support 56, and the color development on one side of a support 64 is shown. Paper 52 provided with an agent layer 62 and a coloring agent layer 66 on the other side, and a support 7
The lower sheet 54 provided with a color developer layer 68 on one side of the lower sheet 54 is overlapped. Reference numeral 60 denotes microcapsules contained in the color forming agent layer. When recording is performed from above the upper paper with a ballpoint pen or the like, between the upper paper and the middle paper, and between the middle paper and the lower paper, the color former layer and the developer layer come into pressure contact and the microcapsules are broken. A coloring reaction occurs, and recording based on the coloring reaction is performed on the middle sheet and the lower sheet, and eventually, three sheets can be recorded simultaneously. As the microcapsules, those obtained by dissolving a color former in an organic solvent, for example, a petroleum solvent such as kerosene, paraffin, naphthenic oil, or alkylnaphthalene, and then microencapsulated with a polyisocyanate compound or the like are used. . It is known that a natural oil such as a vegetable oil can be used as the solvent (Japanese Patent Publication No. 46-13165). However, as described in detail later, since the vapor pressure at room temperature is low and fogging is likely to occur, petroleum oil is actually used. At present, system solvents are used.

On the other hand, it is not an exaggeration to say that in recent years, in the production of industrial products in all fields, it has been demanded to use materials that place less burden on the environment. Attempts have been made to use a biodegradable vegetable oil as a solvent for dissolving the color former, and to use naturally occurring activated clay as a color developer (Japanese Patent Application Laid-Open No. 8-142506).

By the way, the function of the color former is not exerted on a predetermined portion of the color developer layer of the middle sheet of the three-sheet copy non-carbon paper type recording material using the upper sheet, the middle sheet and the lower sheet as described above. In a non-carbon paper type recording material in which a layer of desensitizing ink is provided so that a recorded image is not formed on that part of the middle paper, a layer containing microcapsules using vegetable oil as a solvent for dissolving the color former is used for the medium. When a color-forming agent layer is formed on the opposite side of the paper, the portion provided with the desensitizing ink layer does not develop color, but the desensitizing ink layer is made transparent like a recorded image (for example, text) and recorded. There was a problem that the contents could be read (recognized). This is because when the microcapsules on the lower surface of the middle paper are broken, 100% of the vegetable oil does not transfer to the lower paper, and the vegetable oil hardly evaporates at room temperature. The desensitized ink layer reaches the desensitized ink layer and acts on the desensitized ink to make the portion transparent like a recorded image. FIG. 2 schematically illustrates the movement of the solvent from the broken microcapsules. In FIG. 2, 30 is a paper support, 32 is a color former layer, 34 is a microcapsule containing a pigment, 36 Is the destroyed microcapsule, 3
8 is the developer layer, 40 is the desensitizing ink layer, and the up and down arrows indicate the amount of solvent from the broken microcapsules that tends to penetrate through the paper support rather than being transferred to the underlying paper. It indicates that there are more. In the case of a petroleum organic solvent, the above-mentioned inconvenience hardly occurs because the volatilization speed is high and it is unlikely that the solvent reaches the desensitizing ink through the support of the middle paper. As described above, when a material having a small burden on the environment is used, there have been problems of fog and transparency of a recorded image as described above.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and its object is to sacrifice general performance such as color density and processing stain required for pressure-sensitive recording materials. In the case of a pressure-sensitive recording material that has a small burden on the environment without a burden on the environment, and further provided with a desensitizing ink layer on the surface of the color developer layer, the vegetable oil of the microcapsules permeates between the supports during recording. Another object of the present invention is to provide a pressure-sensitive recording material which does not make the desensitizing ink layer transparent like a recorded image.

[0006]

The above object can be attained by providing the following pressure-sensitive recording material. (1) A color former layer including a microcapsule containing an electron-donating color former dissolved in a solvent composed of vegetable oil is provided on one surface of a support, and on another surface of the support, In a pressure-sensitive recording material provided with a color developer layer containing an electron-accepting color developer, a layer mainly composed of a latex binder is provided between the support and the color former layer, and the color developer is provided. A pressure-sensitive recording material characterized by being activated clay. (2) The pressure-sensitive recording material according to the above (1), wherein the layer mainly composed of the latex binder further contains a water-soluble polymer compound. (3) The pressure-sensitive recording material as described in (1) or (2) above, wherein the color former layer further contains a styrene-butadiene copolymer and polyvinyl alcohol. (4) Any one of the above (1) to (3), wherein a layer of desensitizing ink is formed on the color developer layer.
Pressure-sensitive recording material described in 1.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The pressure-sensitive recording material of the present invention is characterized in that a layer mainly composed of a latex binder is provided between a color former layer and a support. FIG. 1 is a schematic view showing an example of a pressure-sensitive recording material in which a layer mainly composed of a latex-based binder is provided between a support and a color former layer.
Layer 12 mainly composed of latex binder on one side of
And a color forming agent layer 20 containing microcapsules 14 containing an electron donating color forming material dissolved in vegetable oil, and a developing solution containing an electron accepting color developing agent on the other surface of the support 10. The developer layer 16 is provided, and a desensitizing ink layer 18 is further provided at a predetermined position on the surface of the developer layer. In the pressure-sensitive recording material of the present invention, any type of latex can be used as the latex used in the layer mainly composed of a latex binder as long as it has a compatibility with vegetable oil. For example,
Styrene-butadiene copolymer-based latex, vinyl acetate-based latex, acrylate-based latex and the like can be mentioned, and styrene-butadiene copolymer-based latex (SBR) is preferred from the viewpoint of color development performance. As the SBR, those containing 30 to 60% by weight of a styrene monomer are preferably used, and SBR having a carboxyl group or an acrylonitrile group in the molecule is also preferably used from the viewpoint of improving the binder strength.

[0008] The layer mainly composed of a latex-based binder may be, for example, a binder known to the latex, such as sodium alginate, carboxymethylcellulose, or the like.
A coating liquid can be prepared by adding a dispersant such as sodium polyacrylate, a viscosity modifier, a surfactant, and an antifoaming agent. In the present invention, it is preferable that the coating liquid contains a water-soluble polymer compound in order to improve coating properties. By adding a water-soluble polymer compound,
In particular, when a curtain coating method is employed as a coating means, the film stability is improved. Preferred examples of the water-soluble polymer compound include synthetic or natural polymer substances such as polyvinyl alcohol, polyacrylic acid, maleic anhydride-styrene copolymer, starch, casein, gum arabic, carboxymethylcellulose, and methylcellulose. These water-soluble polymer compounds can be used alone or in combination of two or more. From the viewpoint of coloring properties, polyvinyl alcohol is preferably used.

A coating solution containing the above-mentioned latex-based binder as a main component is applied to the surface of the support and dried to form a layer mainly composed of the latex-based binder on the surface of the support. Next, a color former layer is applied on this layer. The layer mainly composed of a latex-based binder formed between the support and the color-forming agent layer contains the latex-based binder in a dry weight of 0.1 to 3.0 g / m ² , preferably 0.3 to 1.5 g.
/ M ² , particularly preferably 0.5 to 1.0 g / m ² . When the coating amount is less than 0.1, the effect of preventing the penetration of the vegetable oil and / or promoting the diffusion of the vegetable oil is not exhibited. It is desirable.

The pressure-sensitive recording material of the present invention shown in FIG.
By providing a layer mainly composed of a latex binder between the color former layer and the support as described above, it is possible to prevent the vegetable oil from penetrating through the support and / or to mainly mix the vegetable oil with the latex binder. It is possible to prevent the vegetable oil from reaching the desensitizing ink layer and making the desensitizing ink transparent by diffusing and swelling in the layer.
Further, even if the vegetable oil penetrates to a certain extent and the desensitizing ink layer becomes transparent, the vegetable oil is prevented from penetrating in the form of a recorded image due to the diffusion action of the vegetable oil in the layer mainly composed of the latex-based binder. It is possible to prevent the layer from becoming transparent like a recorded image.

Next, the color former layer, the developer layer, the support and the desensitizing ink layer of the pressure-sensitive recording material shown in FIG. 1 will be described in detail. The color former layer in the pressure-sensitive recording material of the present invention contains microcapsules containing an electron-donating color former dissolved in vegetable oil. As the microcapsules, those usually used in pressure-sensitive recording materials can be used without any particular limitation.

Vegetable oil is used as a solvent for dissolving the color former contained in the microcapsules. It is a vegetable oil having a fatty acid residue composition with an oleic acid residue content of generally 10 to 60% by weight. Examples of such vegetable oils include soybean oil (oleic acid residue content (OA) in the fatty acid residue composition = 20 to 35% by weight), corn oil (OA = 25 to 45% by weight), rapeseed oil (OA) = 10
-35% by weight), cottonseed oil (OA = 15-30% by weight),
Sesame oil (OA = 35-46% by weight), peanut oil (OA =
35-60% by weight) and sunflower oil (OA = 15-35% by weight). In particular, soybean oil,
Corn oil, rapeseed oil, cottonseed oil, and the like are preferable in terms of high solubility of the color former used, high color developability when reacted with a developer, and industrially easily available, among which rapeseed oil is preferred. It is most preferably used in that the solubility of the color former is high. These vegetable oils may be used alone or in combination. A vegetable oil having an oleic acid content of more than 60% by weight in the fatty acid residue composition, such as olive oil (OA = 70-85 superposition%), has a low dissolving power (solubility) for the color former and is not so preferable.

Even if a solvent other than the vegetable oil conventionally used together with the above-described vegetable oil is used as the solvent in an amount that does not give an unpleasant odor to the recording medium (generally, an amount of 30% by weight or less of the vegetable oil). Good.

As the color former used for forming the microcapsules, it is preferable to use a known color former which can be dissolved in the above-mentioned solvent containing a vegetable oil as a main component. As the color former used in the present invention, an indolylphthalide compound or an indolylazaphthalide compound represented by the following general formula (1), which is easily dissolved in the above-mentioned vegetable oil:

[0015]

Embedded image

(However, R ¹¹ and R ¹² are each independently
R ¹³ represents an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group; R ¹³ represents an alkyl group having 1 to 6 carbon atoms;
¹⁴ represents an alkyl group having 1 to 12 carbon atoms which may have an alkoxy group having 1 to 4 carbon atoms as a substituent, and represents a group represented by R ¹¹ , R ¹² , R ¹³ and R ¹⁴ A ring A represents an unsubstituted benzene ring or a pyridine ring having 10 or more carbon atoms in total) and a fluoran compound represented by the following general formula (2)

[0017]

Embedded image

(Provided that R ²¹ represents an alkyl group having 1 to 4 carbon atoms, R ²² represents a branched alkyl group having 4 to 12 carbon atoms or a tetrahydrofurfuryl group, and R ²¹ and R ²²
R ²³ and R ²⁴ each independently represent a hydrogen atom, a halogen atom or a methyl group).

The indolyl phthalide compound or indolyl azaphthalide compound represented by the general formula (1) has a high solubility in vegetable oils as described above, and forms a color image formed by reacting with a developer. It is a compound that has a high concentration and can be easily and inexpensively synthesized.

Particularly preferred specific examples of the indolylphthalide compound represented by the general formula (1) include 3- (4
-Diethylamino-2-ethoxyphenyl) -3- (1
-N-octyl-2-methylindol-3-yl) phthalide, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-n-hexyl-2-methylindol-3-yl) phthalide, 3 -(4-diethylamino-
2-ethoxyphenyl) -3- (1-n-pentyl-2
-Methylindol-3-yl) phthalide, 3- (4-
Diethylamino-2-ethoxyphenyl) -3- (1-
n-decyl-2-methylindol-3-yl) phthalide, 3- (4-diethylamino-2-ethoxyphenyl) -3- [1- (2-ethylhexyl) -2-methylindol-3-yl] phthalide, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-isopentyl-2-methylindol-3-yl) phthalide, 3
-(4-dipropylamino-2-propoxyphenyl)
-3- (1-Ethyl-2-methylindol-3-yl) phthalide, 3- (4-dibutylamino-2-butoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) phthalide , 3- (4-dibutylamino-
2-ethoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) phthalide, 3- (4-dihexylamino-2-ethoxyphenyl) -3- (1-methyl-2-methylindole- 3-yl) phthalide, 3-
(4-dibutylamino-2-ethoxyphenyl) -3-
(1-β-ethoxyethyl-2-methylindole-3
-Yl) phthalide, 3- (4-diethylamino-2-butoxyphenyl) -3- (1-n-butyl-2-methylindol-3-yl) phthalide, 3- (4-N-ethyl-N-isobutyl Amino-2-ethoxyphenyl)-
3- (1-ethyl-2-methylindol-3-yl)
Phthalide and the like can be mentioned.

Particularly preferred specific examples of the indolylazaphthalide compound represented by the general formula (1) include 3-
(4-diethylamino-2-ethoxyphenyl) -3-
(1-n-octyl-2-methylindol-3-yl) -4- or -7-azaphthalide, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-n-hexyl-2-methyl Indole-3-yl) -4- or -7-azaphthalide, 3- (4-diethylamino-2-
Ethoxyphenyl) -3- (1-n-decyl-2-methylindol-3-yl) -4- or -7-azaphthalide, 3- (4-diethylamino-2-ethoxyphenyl) -3- [1- ( 2-ethylhexyl) -2-methylindol-3-yl] -4- or -7-azaphthalide, 3- (4-dibutylamino-2-butoxyphenyl) -3- (1-ethyl-2-methylindole-3 −
Yl) -4- or -7-azaphthalide, 3- (4-dibutylamino-2-ethoxyphenyl) -3- (1-β-
Ethoxyethyl-2-methylindol-3-yl)-
4- or -7-azaphthalide, 3- (4-diethylamino-2-butoxyphenyl) -3- (1-n-butyl-
2-methylindol-3-yl) -4- or -7-azaphthalide, 3- (4-N-ethyl-N-isobutylamino-2-ethoxyphenyl) -3- (1-ethyl-2
-Methylindol-3-yl) -4- or -7-azaphthalide.

A particularly preferred specific example of the fluoran compound represented by the general formula (2) is 2-anilino-3.
-Methyl-6-N-ethyl-N-isobutylaminofluoran, 2-anilino-3-methyl-6-N-ethyl-
N-isopentylaminofluoran, 2-anilino-3
-Methyl-6-N-methyl-N-isobutylaminofluoran, 2-anilino-3-methyl-6-N-methyl-
N-isopentylaminofluoran, 2-anilino-3
-Methyl-6-N-ethyl-N-isohexylaminofluoran, 2-anilino-3-methyl-6-N-ethyl-N- (2-ethylhexyl) aminofluoran, 2-
Toluidino-3-methyl-6-N-ethyl-N-isobutylaminofluoran, 2-anilino-3-methyl-6
-N-ethyl-N- (2-ethyldecyl) aminofluoran, 2-anilino-3-methyl-6-N-propyl-
N-isobutylaminofluoran, 2- (o-chloroanilino) -6-N-ethyl-N-isobutylaminofluoran, 2-anilino-3-chloro-6-N-ethyl-
N- (sec-butyl) aminofluoran, 2-anilino-3-methyl-6-N-ethyl-N-tetrahydrofurfurylaminofluoran, 2-anilino-3-methyl-6-N-methyl-N- Tetrahydrofurfurylaminofluoran and the like can be mentioned.

For the purpose of adjusting hue, a well-known compound such as an indolylphthalide compound or an indolylazaphthalide compound represented by the general formula (1) and / or a fluoran compound represented by the general formula (2) is well known. Triphenylmethane phthalide compounds, fluoran compounds, phenothiazine compounds, indolyl phthalide compounds, leuco auramine compounds, rhodamine lactam compounds, triphenyl methane compounds, triazene compounds, spiropyran compounds, etc. Various color formers can be used in combination.
At that time, the content of the indolylphthalide compound or the indolylazaphthalide compound represented by the general formula (1) and / or the fluoran compound represented by the general formula (2) is 50% by weight of the total amount of the color former. It is preferable to make the above. That is, by using such a coloring agent composition, it can be easily dissolved in vegetable oil.

In producing a microcapsule containing a coloring agent, a coloring agent solution is generally prepared by dissolving the coloring agent in vegetable oil. The temperature for dissolving the coloring agent in vegetable oil is 80 to 130 ° C. Preferably, there is. At a temperature lower than the above range, the coloring agent is hardly dissolved in the vegetable oil, and at a temperature higher than the above range, the vegetable oil may be deteriorated.
The concentration of the color former in the color former solution is preferably 3 to 12% by weight, particularly preferably 3 to 8% by weight, based on the vegetable oil.

The microcapsules containing the color former dissolved in vegetable oil can be produced by any known per se interfacial polymerization method. As the wall material of the microcapsules, any water-insoluble or oil-insoluble polymer that has been conventionally used as the wall material of the color former-containing microcapsules of the pressure-sensitive recording material can be used without particular limitation. Polyurethane urea resin is particularly preferred because of its high resistance. As a method for preparing a dispersion of microcapsules of polyurethane urea wall material containing a color former, for example, a polyisocyanate and a polyhydric hydroxy compound (optionally) may be added to a vegetable oil solution in which the color former prepared as described above is dissolved. (UV absorber) is added to make a primary solution, which is emulsified and dispersed in a hydrophilic liquid, a polyamine is added to the obtained emulsified dispersion, and a solution of the vegetable oil solution in the emulsified dispersion is added. There is a method in which droplets are coated with a polyurethane urea resin and microencapsulated. Both the polyvalent hydroxy compound and the polyvalent amine may be used, or either one may be used.
Without the use of polyamines, the rate at which the polyisocyanate reacts with water generally increases.

The polyvalent isocyanate used in the present invention includes isocyanurate of hydrogenated xylylene diisocyanate (generally called hydrogenated XDI), isocyanurate of isophorone diisocyanate (generally called IPDI), and 4,4 ′ -Diphenylmethane diisocyanate, an adduct of hexamethylene diisocyanate with trimethylolpropane, a biuret of hexamethylene diisocyanate, an isocyanurate of hexamethylene diisocyanate, polymethylene polyphenylisocyanate, carbodiimide-modified diphenylmethane diisocyanate, tolylene diisocyanate and trimethylolpropane. Adduct of xylylene diisocyanate with trimethylolpropane, isoad of tolylene diisocyanate Cyanurate form, adduct of hydrogenated xylylene diisocyanate and trimethylolpropane,
An adduct of isophorone diisocyanate with trimethylolpropane, a biuret of xylylene diisocyanate, and tris- (p-isocyanatophenyl) thiophosphite can be exemplified.

The compound having two or more active hydrogens in the molecule to be polymerized with the polyisocyanate is water, a polyhydroxy compound and / or a polyamine. Specific examples of the above polyhydric hydroxy compound include aliphatic or aromatic polyhydric alcohols, hydroxy polyesters, hydroxy polyalkylene ethers, and alkylene oxide adducts of polyvalent amines.

The above polyamine compound is a compound having two or more —NH— groups or —NH ₂ groups in a molecule and soluble in a hydrophilic liquid. Specific examples of the polyamine compound include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, 1,3-propylenediamine, hexamethylenediamine, phenylenediamine, diaminonaphthalene,
Xylylenediamine and the like.

Further, since the microcapsules of the present invention contain vegetable oil as an organic solvent, from the viewpoint of production, the wall material of the microcapsules of the present invention should be added to vegetable oil at 50 ° C., especially 5% by weight or more of the weight of vegetable oil. , Preferably 5 to 1
It is preferably a polyurethane urea resin obtained by polymerization of an aliphatic polyisocyanate having a property of dissolving 0% by weight and a compound having two or more active hydrogens in a molecule, and the polyurethane urea resin has resistance to thermal fog. Is particularly large.

The aliphatic polyisocyanate compound is
In order to form a dense capsule wall, it is preferable to use two or more kinds in combination. The aliphatic polyisocyanate preferably has an alkylene group having 4 to 10 carbon atoms (particularly, 4 to 8 carbon atoms) in the molecule. It is also preferable that the aliphatic polyisocyanate has an isocyanurate skeleton. In addition, the aliphatic polyisocyanate is preferably an isocyanurate of hexamethylene diisocyanate and an aliphatic diol (eg, an alkylene diol) through a urethane bond to the isocyanurate.
Is preferably a mixture with a compound bound to. Examples of the aliphatic polyisocyanate that is soluble in vegetable oil in an amount of 5% by weight or more include an isocyanurate derivative of hexamethylene diisocyanate. Such isocyanurate derivatives include, for example, Vernock DN9
90S and Barnock DN991S (manufactured by Dainippon Ink and Chemicals, Inc.) are available and can be obtained.

In the formation of the microcapsules, other polyisocyanates may be used together with the specific aliphatic polyisocyanate in an amount of 30% by weight or less of the total polyisocyanate. At that time, in order to form a dense capsule wall in the vegetable oil, it is preferable to use a polyisocyanate having relatively high affinity with the vegetable oil. For example, trimethylolpropane adduct of isophorone diisocyanate, isocyanurate of isophorone diisocyanate, isocyanurate of xylylene diisocyanate, and the like can be given. Alternatively, a small amount of aromatic polyisocyanate (for example, diphenylmethane diisocyanate) may be used to impart strength to the capsule wall.

When the above-mentioned aliphatic polyisocyanate having the property of dissolving in vegetable oil at 50 ° C. in an amount of 5% by weight or more based on the weight of vegetable oil is used, after emulsification and dispersion as described above,
Capsule wall of polyurethane urea which is polymerized selectively with water in a dispersion medium or polyhydric hydroxy compound or polyamine so as to enclose oil droplets of a coloring agent dissolved in vegetable oil, and around the oil droplets. Can be formed. Therefore,
By using the thus obtained microcapsules as a recording material, it is possible to obtain a recording material which does not generate stain during coloring and does not generate fog even under high temperature and high humidity.

The dispersion of microcapsules prepared as described above may be used directly as a coating solution for forming a colorant layer, or a binder or a capsule protective agent may be further added to the dispersion of microcapsules to form a colorant layer. A coating solution for formation is prepared, coated on a support by a method known per se, and dried to form a color former layer of a carbonless paper type pressure-sensitive recording material. As the binder, a water-soluble binder, a latex-based binder, or the like can be used. As the capsule protective agent, cellulose powder, starch particles, talc, or the like can be used.

In particular, in the pressure-sensitive recording material of the present invention, a styrene-butadiene copolymer rubber (SB
Preferably, R) and polyvinyl alcohol are added to form a colorant coating solution. SBR having a styrene monomer content of 30 to 60% by weight is preferably used, and SBR having a carboxyl group in the molecule is also preferably used from the viewpoint of improving the binder strength. It is preferable to use an aqueous dispersion (SBR latex) as the SBR to be added to the coating solution for forming a color former layer. The addition amount is 10 to 150% by weight, preferably 2% by weight, based on the vegetable oil contained in the color former microcapsules, as the SBR solid content of the SBR dispersion.
0 to 120% by weight, particularly preferably 40 to 100% by weight
Is added. If the amount is less than 10% by weight, the effect of preventing penetration or promotion of diffusion will not be exhibited, and if it is more than 150% by weight, the color density will be low. Also, as polyvinyl alcohol,
Either fully saponified polyvinyl alcohol or partially saponified polyvinyl alcohol can be used.
Up to 90% of partially saponified polyvinyl alcohol is preferably used in terms of improving the stability and hydrophobicity of the capsule solution. The amount added is 5 to 10 based on the vegetable oil contained in the color former microcapsules as polyvinyl alcohol solids.
0% by weight, preferably 10 to 80% by weight, particularly preferably 20 to 60% by weight. If the amount is less than 5% by weight, the effect of preventing permeation or promotion of diffusion will not be exhibited, and if it is more than 100% by weight, the color density will be low.

The support may be any support conventionally used as a support for pressure-sensitive recording materials, for example, paper from wood pulp, paper treated with this paper, synthetic paper from plastics material. , Plastics film and the like can be used.

The final coating amount of the color former applied to the support is as follows:
0.05 to 0.30 g / m ² , preferably 0.08 to
0.20 g / m ² is appropriate.

Next, the developer layer of the pressure-sensitive recording material of the present invention will be described. In the present invention, the color developer layer contains activated clay as a color developer. Activated clay is superior to salicylic acid derivatives, etc., which are organic color developers, even when vegetable oil is used as a solvent for dissolving the color former, it has excellent color developability and is naturally produced, so from an ecological point of view Is also excellent.

The coating solution for forming the color developer layer is as follows:
It can be prepared by a method known per se, for example, obtained by dispersing activated clay in water by a known method.
The coating solution further contains, as a binder, styrene-butadiene copolymer latex, vinyl acetate latex, acrylate latex, polyvinyl alcohol, polyacrylic acid, maleic anhydride-styrene-
It may contain a synthetic or natural polymer such as a copolymer, starch, casein, gum arabic, gelatin, carboxymethylcellulose, methylcellulose and the like. The formation of the color developer layer on the support as described above can also be performed by a method known per se.

The final coating amount of the developer applied to the support is as follows:
^{0.1g / m 2 ~4.0g / m 2} , preferably 0.2g
/ M ^{2 to} 3.0 g / m ² is appropriate.

Next, the desensitizing ink which can be used in the present invention will be described. As the desensitizing ink, the desensitizing ink used for non-carbon paper can be used without any particular limitation. Generally, desensitizing inks include those in which a desensitizing agent, a binder, a pigment, etc. are dissolved in an organic solvent, and a color forming agent and a developing color provided by providing a physical shielding layer of a resin film without using a desensitizing agent. There are things that prevent the contact of the agent,
As the desensitizing ink that can be used in the present invention, either a type containing the above-described desensitizer or a type not containing the desensitizing agent can be used.

As a desensitizer used in a desensitizing ink prepared by adding a binder, a pigment, and the like to a desensitizer, a conventionally used desensitizer can be used without any particular limitation. For example, alkyl or dialkyl quaternary ammonium salts of JP-B-45-21488, JP-B-46-2
Amines and glycols having a large dielectric constant of No. 2651,
JP-B-47-38201, alkyloxy, alkylester or alkylphenol ether of polyoxyethylene glycol, and / or a copolymer of polyoxyethylene and polyoxypropylene, an average molecular weight of 400 described in JP-A-50-37507. ~ 500
0 polypropylene glycol, JP-A-54-1049
No. 12, alkoxylated nucleophilic compounds described in JP-B-55-1919, polypropylene glycol having an average molecular weight of 400 to 5,000, and those comprising propylene glycol and carboxylic acid esters described in JP-A-55-46991. JP-A-55-51586, alkyl ether of copolymer of ethylene oxide and propylene oxide, JP-A-55-51587, copolymer of ethylene oxide and propylene oxide, JP-A-56-672
An alkylene oxide adduct of the amine of No. 91,
40% or more of the alkylene oxide is butylene oxide, and an alkylene oxide adduct such as urea, alkylamide, or allylamide disclosed in JP-A-56-142093, wherein 40% or more of the alkylene oxide is butylene oxide. Examples thereof include, but are not limited to, alkylene oxide adducts of polyalkyleneimine described in JP-A-62-268683.

The amount of the desensitizer added is based on the amount of the desensitized ink layer.
It is 10 to 50% by weight, preferably 20 to 45% by weight. Pigments used with desensitizers include titanium white, organic bentonite, silica gel, barium sulfate,
White pigments such as calcium carbonate, talc and kaolin are used. The addition amount is 0 to 50 based on the solid content of the desensitizing ink.
%, Preferably 3 to 20% by weight. As the binder of the desensitizing ink, ultraviolet curable resin, rosin-modified phenolic resin, phenolic resin, ketone resin, polyamide resin, rosin-modified maleic resin, maleic resin, epoxy resin, alkyd resin, melamine resin, urea resin,
Nitrocellulose, ethylcellulose, butyral resin, polyvinyl alcohol resin, gelatin and the like are used. The binder is added to the desensitizing ink so that the binder is contained in the desensitizing ink layer in an amount of 5 to 40% by weight, preferably 10 to 30% by weight.

In particular, as a desensitizing ink of the type which prevents the contact between the color former and the developer by providing a physical shielding layer made of a resin film without using a desensitizer, for example, a photo-crosslinkable compound or a photo-sensitive type An ultraviolet curable resin obtained by adding a sensitizer, a polymerization inhibitor and the like to a polymerizable compound is used.

In the present invention, a desensitizing ink containing a desensitizing agent and using an ultraviolet curable resin as a binder is preferably used for preventing transparency. Examples of commercially available desensitizing inks include "UV desensitizing inks" (manufactured by Fuji Photo Film Co., Ltd.) using a UV curable resin as a binder containing a desensitizing agent, and offset and letterpress type desensitizing inks. “FN104” (manufactured by Fuji Photo Film Co., Ltd.), “FN300” (manufactured by Fuji Photo Film Co., Ltd.) as a desensitizing ink for toughness, and “FN1000VS” (Fuji Photo Film Co., Ltd.) as a waterless lithographic desensitizing ink. ))). Among them, “UV desensitizing ink” and “FN300” are preferably used.

[0045]

The present invention will be described below in more detail with reference to examples, but the present invention is not limited thereto. Example 1 [Preparation of Coating Solution-A for Forming Coloring Agent Layer] As a coloring agent, 4.0 g of crystal violet lactone, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-n)
-Octyl-2-methylindol-3-yl) phthalide 2.5 g and benzoylleucomethylene blue 1.0
g was dissolved in 120 g of rapeseed oil by heating at 130 ° C. for 1 hour. The obtained oily liquid was cooled to 60 ° C., and then 8 g of Vernock DN990S (solid content: 100%, manufactured by Dainippon Ink and Chemicals, Inc.), which is an aliphatic isocyanate,
1.0 g of Cosmonate LK, an aromatic isocyanate (manufactured by Mitsui Toatsu Chemicals, Inc., solid content: 100%), and a butylene oxide adduct of ethylenediamine as an alkylene oxide adduct of amine (the number of moles of butylene oxide added to ethylenediamine) 16.8 mol,
1.6 g (molecular weight: 1267) was dissolved to prepare a primary solution.

Next, 15 g of polyvinyl alcohol (trade name "PVA-205", manufactured by Kuraray Co., Ltd.) was added to 140 g of water.
g was dissolved to prepare a secondary solution. While vigorously stirring the secondary solution, the primary solution was poured into the secondary solution to form an oil-in-water emulsion. When the size of the oil droplets reached 8.0 μm, the stirring was weakened. Then, 10 g of a 5% by weight aqueous solution of tetraethylenepentamine and 100 g of water at 20 ° C. were added to the emulsion, and the temperature of the system was gradually lowered. The temperature was raised to 80 ° C. and maintained at this temperature for 90 minutes.

The capsule liquid thus obtained was added to polyvinyl alcohol (Kuraray Co., Ltd., trade name “PVA”).
-217E "), 120 g of carboxy-modified SBR latex (manufactured by Sumika ABS Latex Co., Ltd., trade name: NOGATEX 2752E) as a solid content, and wheat starch particles (average particle diameter: 20).
70 μm). Then, water was added to adjust the solid content concentration to 20% by weight, and the colorant layer-forming coating solution-A was added.
And

[Preparation of Coating Solution-A for Forming Developer Layer] Water 1
5 g of a 20% by weight aqueous sodium hydroxide solution
1 g by weight of sodium hexametaphosphate was added. To the obtained solution, 2 g of magnesium oxide and activated clay as a color developer (trade name "Silton F-24" manufactured by Mizusawa Chemical Industry Co., Ltd.)
2 "), and homogenizer (AM-7,
The mixture was dispersed at 10,000 rpm for 5 minutes using Nippon Seiki Co., Ltd. to obtain a developer dispersion. 1% by weight in 5g of flour
A starch aqueous solution was prepared by dissolving in 100 g of an aqueous sodium hydroxide solution. A starch aqueous solution 3 was added to 100 g of the developer dispersion.
5 g and 15 g (solid content) of SBR latex were added,
Further, water was added to adjust the solid content concentration to 20% by weight to prepare a developer layer forming coating solution A.

[Preparation of Developer Sheet A] 50 g / m^Twoof
On one side of the base paper, 5.0 parts of the above-mentioned coating solution-A for forming a developer layer was applied.
g / m ^TwoUse a bar coater to apply
It was applied and dried to prepare a developer sheet A.

[Preparation of Medium Paper] A carboxy-modified SBR latex (trade name: NOGATEX 2752E, manufactured by Sumika ABS Latex Co., Ltd.)
So that 2.0 g / m ² as a solid content is applied,
It was applied and dried using a bar coater. The coating solution-A for forming a color former layer is applied in a multi-layered manner using a bar coater such that a solid content of 4.0 g / m ² is applied on the surface on which the carboxy-modified SBR latex is applied, and then dried. I got the paper.

Example 2 A carboxy-modified SBR latex (manufactured by Sumika ABS Latex Co., Ltd., trade name:
Nogatex 2752E) and polyvinyl alcohol (manufactured by Kuraray Co., Ltd., trade name: PVA-217E) were applied at a solid content of 2.0: ² g / m ² as a solid content. To be,
Coating and drying were performed using a curtain coater. Then, 4.0 g / m of the coating solution-A for forming a colorant layer was applied on the coated surface.
Using a bar coater so that the solid content of No. ² was applied, it was dried and a medium paper was obtained.

COMPARATIVE EXAMPLE 1 A color former layer forming coating solution-A was applied to the back surface of the developer sheet A using a bar coater so that a solid content of 4.0 g / m ² was applied, and dried. To obtain medium paper.

[Evaluation Test] (1) Evaluation of Transparency Level of Printed Area of Desensitized Ink Printed Area Using the respective pressure-sensitive recording sheets (medium paper) obtained in Examples and Comparative Examples with an RI tester. A desensitizing ink for pressure-sensitive copying paper (FN300: manufactured by FUJIFILM Corporation) was printed on the surface coated with the developer so as to have a filling amount of 3 g / m ² .
Pressure-sensitive recording sheet (upper paper, Fuji Photo Film Co., Ltd.)
Pressure-sensitive recording sheet (medium paper) on which the desensitizing ink layer is printed as described above.
Impact printer (Microline 83
40SV) to perform pressure printing. It was visually observed whether the printed portion of the desensitized printing portion of the middle paper became transparent and could be read as characters, and the degree was evaluated according to the following criteria.

A: Not transparent at all. B: Although slightly transparent, it is impossible to read the printed content from the transparent portion, and there is no practical problem. C: It is transparent, and a considerable part of the printed content can be read from the transparent portion, which poses a practical problem. D: Transparency is remarkable, the printed content is almost legible, and is impractical.

(2) Evaluation of print fog level Using the pressure-sensitive recording sheets (middle paper) obtained in Examples 1 and 2 and Comparative Example 1, letterpress printing was performed on the surface of the developer layer with yellow ink. Then, it was visually observed whether the yellow ink was discolored by fog. A: The yellow ink is not discolored at all. B: The yellow ink is slightly discolored, but there is no practical problem. C: Discoloration of the yellow ink is remarkable, and there is a problem in practical use. D: Discoloration of the yellow ink is remarkable, making it impractical.

[0056]

[Table 1]

In each of the recording materials (middle paper) produced in Examples 1 and 2, the level of transparency of the printed portion of the desensitized ink printing portion was very small, and the printed content was completely unreadable. , Other general performance, such as color density,
The color stain during processing did not deteriorate at all. On the other hand, a pressure-sensitive recording material in which a layer mainly composed of a latex-based binder was not provided between the support and the color-forming agent layer was remarkably transparent, and the printed content was almost readable, so that it was not practical. It can be seen that the present invention is also excellent in printing fog. In the recording materials of Examples 1 and 2, the characteristics such as color density and color stain during processing are comparable to those of a general pressure-sensitive recording material having no layer mainly composed of the latex binder. Was. Furthermore, in Example 2, although a layer mainly composed of a latex-based binder was formed by using a curtain coater method, a good film could be formed.

Example 3 A medium sheet was prepared in the same manner as in Example 1 except that a desensitizing ink manufactured by Fuji Photo Film Co., Ltd. (trade name "UV desensitizing ink") was used as the desensitizing ink. In the same manner as described above, an evaluation test of transparency and print fog level was performed. As a result, both of them obtained the rating of A rank.

[0059]

As described above, the present invention provides the general performance required for a pressure-sensitive recording material by providing a layer mainly composed of a latex binder between the support and the color former layer in the pressure-sensitive recording material. For example, it has the effect of preventing the desensitized ink layer from becoming transparent like a recorded image at the time of recording, without deteriorating the coloring density, coloring stains during processing, etc., and has the effect of making the recorded contents unreadable. And has improved print fog resistance.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a pressure-sensitive recording material of the present invention in which a layer mainly composed of a latex binder is provided between a support and a color former layer.

FIG. 2 is a conceptual diagram showing the movement of a solvent when a microcapsule of a color former layer on the lower surface of a middle sheet is broken.

FIG. 3 is a schematic cross-sectional view of a pressure-sensitive recording material in which an upper sheet, a middle sheet, and a lower sheet are stacked.

[Explanation of symbols]

 Reference Signs List 10 support 12 layer mainly composed of latex binder 14 microcapsule 16 developer layer 18 desensitizing ink layer 20 color former layer

Claims (4)

[Claims] 1. A color former layer comprising microcapsules containing an electron-donating color former dissolved in a solvent composed of vegetable oil is provided on one side of a support, and the other side of the support is provided with a color former layer. In a pressure-sensitive recording material provided with a developer layer containing an electron-accepting developer, a layer mainly composed of a latex binder is provided between the support and the color former layer,
And a pressure-sensitive recording material, wherein the developer is activated clay. 2. The pressure-sensitive recording material according to claim 1, wherein the layer mainly composed of a latex-based binder further contains a water-soluble polymer compound. 3. The pressure-sensitive recording material according to claim 1, wherein the color former layer further contains a styrene-butadiene copolymer and polyvinyl alcohol. 4. The pressure-sensitive recording material according to claim 1, wherein a layer of a desensitizing ink is formed on the developer layer.