JPH0615951A - Color developing agent for pressure-sensitive recording paper and color developing sheet - Google Patents

Abstract

PURPOSE:To provide a color developing agent for a pressure-sensitive recording paper exhibiting a high color developing speed and a high color developing density and a color developing sheet. CONSTITUTION:A color developing agent for a pressure-sensitive recording paper characterized by consisting of a polyvalent metal salt of a salicylic acid derivative and a polyoxyalkylene and a color developing sheet wherein a layer contg. the color developing agent is formed into a sheet-like shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color developing agent and a color developing sheet for pressure-sensitive recording paper containing a polyvalent metal salt of a salicylic acid derivative as a main component.

[0002]

2. Description of the Related Art Conventionally, a polyvalent metal salt of a salicylic acid derivative has been known as a developer for pressure-sensitive recording paper. Further, in recent years, with the increase in simultaneous copying of a large number of sheets, there is a demand for a color-developing sheet that develops a faster coloring speed and higher coloring density than before with a small external force. Various attempts have been proposed to deal with this, for example, those prepared by blending a surfactant in an organic solvent solution of the polyvalent metal salt of the salicylic acid derivative (JP-A-63-98483), What is obtained by dissolving a salicylic acid derivative polyvalent metal salt in a vegetable oil and an organic solvent having a boiling point of 200 ° C. or lower (JP-A-4-52184), the polyvalent metal salt of the salicylic acid derivative being a boiling point of a biphenyl derivative or the like 15
Those which are dissolved in an organic solvent having a high boiling point of 0 ° C. or higher (for example, JP-A-54-14332 and JP-A-59-202889) are known.

[0003]

However, these conventional color developers are not sufficiently satisfactory in that they have a high color development speed and a high color density at the same time.

[0004]

The present inventors have arrived at the present invention as a result of extensive studies to solve the above problems.
That is, the present invention provides a developer for pressure-sensitive recording paper, which comprises a polyvalent metal salt of a salicylic acid derivative (A) and polyoxyalkylene (B), and a layer containing the developer on a sheet. Is a color-developing sheet formed on.

In the salicylic acid derivative in (A) of the present invention, one or more hydrogens at the 3 to 6 positions of salicylic acid has 4 carbon atoms.
The above alkyl group, cycloalkyl group, alkoxy group,
Aryl group, aryloxy group, alkylaryl group,
Nuclear-substituted salicylic acid having 1 to 4 substituents substituted with aralkyl group or halogen, salicylic acid resin having two or more salicylic acid units in main chain or side chain as partial skeleton, and mixture of two or more thereof And specifically include the following compounds.

Nuclear-substituted salicylic acid having 1 to 4 substituents 3-α-methylbenzyl salicylic acid, 5-α-methylbenzyl salicylic acid, monosubstituted salicylic acid such as 5-benzyl salicylic acid; 3,5-di (α -Methylbenzyl) salicylic acid,
3,5-di (tert-butyl) salicylic acid, 3,5-di (α, α-dimethylbenzyl) salicylic acid, 3,5-di (cyclohexyl)
Di-substituted salicylic acid such as salicylic acid described in JP-A-4-31082; 3-α-methylbenzyl-5- (1,3-diphenylbutyl) salicylic acid, 3- (1,3-diphenylbutyl) -5-
α-methylbenzyl salicylic acid, 3-α-methylbenzyl-5
Salicylic acid 1 such as-[α-methyl-4 '-(α-methylbenzyl) benzyl] salicylic acid and 3- [α-methyl-4'-(α-methylbenzyl) -benzyl] -5-α-methylbenzylsalicylic acid Mol and styrene derivative 3 mol reaction products.

Salicylic Acid Resins Condensates of salicylic acid with α, α'-dialkoxy-p-xylene and the like described in JP-A-62-176875 and JP-A-62-178387, JP-A-64-56724, Condensates of salicylic acid or the above-mentioned nucleus-substituted salicylic acid described in JP-A-2-160815 with styrene, benzyl halide, benzyl ether, benzyl alcohol, etc., obtained by reaction with cyclic terpenes described in JP-A-62-19486. Carboxy-modified terpene phenol resins obtained, polymer compounds having salicylic acid units described in JP-A No. 3-13378, and the like.

The polyvalent metal constituting (A) is 2
Valent, trivalent or tetravalent metals such as zinc, calcium, magnesium, barium, lead, aluminum, zirconium, vanadium and tin. Of these, preferred are zinc, aluminum and tin, and particularly preferred is zinc.

The polyoxyalkylene or its derivative (B) in the present invention includes polyethylene ether glycol, polypropylene ether glycol, polybutylene ether glycol, polytetramethylene ether glycol, and a block copolymer containing two or more of these in the molecular skeleton. The polymer or random copolymer, and one end or both ends of the above polyoxyalkylene have 1 to 6 carbon atoms.
Is at least one selected from compounds substituted by an alkoxy group or an acyloxy group (excluding a surfactant). Of these, preferred are polytetramethylene ether glycol and block or random copolymers containing a polytetramethylene ether skeleton, and particularly preferred is polytetramethylene glycol.

The number average molecular weight of (B) used in the present invention is 50.
It is 0 to 30000, preferably 600 to 4000. When the number average molecular weight is less than 500, the color developing speed of the color developer decreases, and when it exceeds 30,000, the compatibility with the above (A) deteriorates.

The amount of (B) in the present invention is usually 1 to 30% by weight, preferably 2 to 30% by weight, based on the weight of (A). If the content of (B) is less than 1% by weight, the effect of increasing the coloring speed is poor, and if it exceeds 30% by weight, the color density is lowered.

As a method for mixing (A) and (B), a generally known method can be used. For example, a method in which (A) and (B) are heated and melt-mixed to form a developer, (A) and ( B)
An appropriate amount of toluene, methyl ethyl ketone, ethyl acetate,
There is a method of mixing and dissolving in an organic solvent such as ethylene dichloride to prepare a developer solution.

The color developer in the present invention is usually used by dispersing it in water. The water dispersion method is not particularly limited, for example, in the presence of a dispersant such as a water-soluble polymer or a surfactant, the developer in water in a ball mill, a grinder such as an attritor or a sand grinder,
A method of pulverizing and dispersing into fine particles having a particle size of 2 μm or less, a developer is dissolved in an organic solvent such as toluene, methyl ethyl ketone, ethyl acetate, ethylene dichloride, and further, if necessary, methyl alcohol, ethyl alcohol, acetone, dioxane, etc. Add a water-soluble solvent to the solution,
In the presence of a water-soluble polymer and / or a dispersant such as a surfactant, a method such as forced stirring with a homomixer, a high-pressure homogenizer or the like to make the particles finer to about 0.1 to 2 μm, and then distilling off the organic solvent can be mentioned.

The aqueous dispersion of the color developing agent for pressure-sensitive recording paper of the present invention, if necessary, may be mixed with a binder, a pigment, an antifoaming agent, a thickening agent and other auxiliary agents, and coated on a substrate such as paper. Be engineered. If necessary, known developers (for example, inorganic solid acids such as activated clay and bentonite; phenol-based condensates such as substituted phenol-formaldehyde resin and bisphenol A-formaldehyde resin) can be used in combination.

Examples of the binder include starch and its derivatives, cellulose derivatives such as carboxymethyl cellulose; carboxyl group-containing (co) polymers such as sodium polyacrylate; water-soluble polymers such as polyvinyl alcohol. A rubber latex such as a styrene / butadiene copolymer can also be used.

Examples of pigments include kaolin, clay, talc, calcium carbonate, titanium oxide, silica, zinc oxide,
Examples thereof include inorganic pigments such as aluminum hydroxide and barium sulfate, and organic fine powders such as urea-formalin resin and polystyrene.

The color developing sheet of the present invention can be obtained by applying the above-mentioned coating liquid on a sheet-shaped support and drying it.

Examples of the support include paper, synthetic paper, synthetic resin film and the like, and paper is particularly preferable.

The method for forming the coating layer on the sheet of the above-mentioned color developer coating solution is not particularly limited, and conventionally known techniques can be used. For example, the coating liquid is applied to the support with an air knife coater, a blade coater, a roll coater or the like, and the coating layer is usually formed by drying at 20 to 120 ° C. The coating amount on the support is not particularly limited, but usually 0.5
-20 g / m < ² >, preferably 2-10 g / m < ² >. The concentration of the salicylic acid derivative polyvalent metal salt in the coating layer is usually 3 to 30% by weight.

[0020]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. In addition, part and% show a weight part and weight%, respectively.

Example 1 100 parts of zinc 3,5-di (α-methylbenzyl) salicylate and 5 parts of polytetramethylene ether glycol having a number average molecular weight of 3000 (hereinafter abbreviated as PTMG) were added to 100 parts of toluene and a temperature of 70. The mixture was dissolved and mixed at ° C to obtain a toluene solution of the color developer.

Example 2 100 parts of zinc 3,5-di-tert-butylsalicylate and 5 parts of polyethylene glycol having a number average molecular weight of 1000 (hereinafter abbreviated as PEG) were mixed and dissolved in 100 parts of toluene at room temperature, and the mixture was exposed. A toluene solution of a coloring agent was obtained.

Example 3 10 parts of PTMG having a number average molecular weight of 1000 was added to 100 parts by weight of zinc 3,5-di (α-methylbenzyl) salicylate, heated to 130 ° C., and then uniformly mixed to give a color developer. Obtained.

Example 4 100 parts of zinc 3,5-di (α-methylbenzyl) salicylate and terminal PEG-modified PTMG (PEG) having a number average molecular weight of 1400
7 parts of a skeleton content of 10%) was dissolved and mixed in 100 parts of toluene at room temperature to obtain a toluene solution of a color developer.

Example 5 To 200 parts of water, 200 parts of the developer solution of the developer of Example 1 in "Kuraray Poval PVA 205" {manufactured by Kuraray Co., Ltd.} 8
Part of the solution was added with stirring with a homomixer (made by Tokushu Kiki Co., Ltd.) with a rotation speed of 10,000 rpm to obtain an average particle size of 0.5 μm.
A toluene solution dispersion of was obtained. Next, the toluene solution dispersion is heated to distill off the toluene, and then xanthan gum 2%
15 parts of an aqueous solution was added to obtain an aqueous dispersion having a solid content of 51.0%.

Example 6 Using the toluene solution of the color developing agent of Example 2, an aqueous dispersion of the color developing agent was obtained in the same manner as in Example 5.

Example 7 After 130 parts of the developer of Example 3 was heated to 70 ° C., 70 parts of toluene was added to prepare a toluene solution of the developer. Toluene solution of the color developer was added to 200 parts of water to obtain "Kuraray Poval PVA.
205 "was added to an aqueous solution in which 8 parts were dissolved while stirring with a homomixer (made by Tokushu Kiki Co., Ltd.) having a rotation speed of 10,000 rpm to obtain a toluene solution dispersion having an average particle diameter of 0.5 µm. Next, the toluene solution dispersion was heated to distill off the toluene, and then 15 parts of a 2% xanthan gum aqueous solution was added to obtain an aqueous developer dispersion having a solid content of 51.0%.

Example 8 Using the toluene solution of the color developing agent of Example 4, an aqueous dispersion of the color developing agent was obtained in the same manner as in Example 5.

Example 9 20 parts by weight of calcium carbonate, 0.1 part by weight of sodium hexametaphosphate, 20 parts of 10% aqueous solution of "Kuraray PVA 117", and 55.9 parts of water were added to 4 parts by weight of the aqueous dispersion of the developer of Example 5.
Part by weight was mixed to obtain a coating liquid. Next, this coating solution, a total dry weight of 50 g / m ² of high-quality paper, coated with a coating rod so that the amount of zinc salt of salicylic acid derivative is 5 g / m ² ,
It dried at room temperature and produced the color development sheet. 23 ℃, 50% RH
In the room of constant temperature and humidity, the coated surface of this color developing sheet and the commercially available blue coloring top paper using crystal violet as a coloring dye were superposed. After passing this through a roll calendar,
The color density after 15 seconds, 60 seconds, and 1 hour was measured with a Macbeth densitometer.

Example 10 Using the aqueous dispersion of Example 6, a color developing sheet was prepared in the same manner as in Example 9 and the color density was measured.

Example 11 Using the aqueous dispersion of Example 7, a color developing sheet was prepared in the same manner as in Example 9 and the color density was measured.

Example 12 Using the aqueous dispersion of Example 8, a color developing sheet was prepared in the same manner as in Example 9 and the color density was measured.

Comparative Example 1 50% toluene solution of zinc 3,5-di-tert-butylsalicylate 2
Add 00 parts to 200 parts of water containing 8 parts of "Kuraray Poval 205" and 5 parts of sodium polyoxyethylene nonylphenyl ether sulfate while stirring with a homomixer (made by Tokushu Kiki) at a rotation speed of 10,000 rpm to obtain an average particle diameter. An aqueous dispersion of a 0.5 μm toluene solution was obtained. Next, the toluene solution dispersion is heated to distill off the toluene, and then xanthan gum 2%
15 parts of an aqueous solution was added to obtain an aqueous developer dispersion having a solid content of 51.0%. Using this aqueous dispersion, a color developing sheet was prepared in the same manner as in Example 9, and the color density was measured.

Comparative Example 2 30 parts by weight of zinc 3,5-di (α-methylbenzyl) salicylate was dissolved in a mixture of 60 parts of cottonseed oil and 30 parts of toluene. Using this toluene solution, the aqueous developer dispersion prepared in the same manner as in Example 5 was used to prepare a developer sheet in the same manner as in Example 9, and the color density was measured.

Comparative Example 3 50% of zinc 3,5-di (α-methylbenzyl) salicylate alone
Using a toluene solution, an aqueous dispersion of the color developer prepared in the same manner as in Example 5 was used to prepare a color developing sheet in the same manner as in Example 9, and the color density was measured.

The results of Examples 9 to 12 and Comparative Examples 1 to 3 are shown in Table 1 below.

[0037]

[Table 1]

[0038]

The color developer and color developing sheet for pressure-sensitive recording paper of the present invention exhibit a faster color-developing speed and a higher color-developing density than conventional ones, and are therefore extremely useful as pressure-sensitive recording materials.

Front page continuation (72) Inventor Yasuo Otani 1-11, Hitotsubashi-honcho, Higashiyama-ku, Kyoto Sanyo Chemical Industry Co., Ltd.

Claims (7)

[Claims] 1. A polyvalent metal salt (A) of a salicylic acid derivative,
A developer for pressure-sensitive recording paper, which comprises polyoxyalkylene or a derivative thereof (B). 2. The color developer according to claim 1, wherein the polyvalent metal (A) is zinc. 3. The color developer according to claim 1, wherein (B) is at least one selected from a block copolymer or a random copolymer containing a polytetramethylene ether glycol and a polytetramethylene ether skeleton. . 4. The color developer according to claim 1, wherein the number average molecular weight of (B) is 500 to 30,000. 5. The amount of (B) is 1 to 1 based on the weight of (A).
The developer of any one of claims 1 to 4, which is 30% by weight. 6. The color developer according to claim 1, wherein (A) and (B) are dispersed in water. 7. A color-developing sheet having a layer containing the color-developing agent according to claim 1 formed on the sheet.