JPH0346313B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel color developer for pressure-sensitive recording paper in which a phenolic resin contains propane derivative phenols as an essential component. It provides colorants. Pressure-sensitive recording generally involves the reaction between a colorless electron-donating organic compound (hereinafter referred to as a color former) and an electron-accepting color developing substance (hereinafter referred to as a color developer) that can react with it to form a colored product. It was used. Conventionally, acid clay, zeolite,
Inorganic clays such as bentonite and kaolin, and phenol-aldehyde condensates (phenolic resins) are known. Phenol resins, especially para-substituted bifunctional phenol/formaldehyde condensates, have superior performance in forming moisture-resistant colored images compared to inorganic clays, and have already been put to practical use as color developers and have undergone many improvements. is being done. Namely, Special Publication No. 1972-20144, Special Publication No. 1973
Publication No. 37451 discloses the use of a para-substituted bifunctional phenol/aldehyde condensate as a color developer. However, although these color developers have the ability to form a moisture-resistant color image, the color development speed is insufficient, and the color changes to yellow or the color image fades when exposed to white light. It has the disadvantage of As a method for improving color development and weather resistance, Japanese Patent Publication No. 47-20971 describes a method of adding a divalent metal salt such as zinc chloride to a para-substituted bifunctional phenol/aldehyde condensate; −
Publication No. 25744 describes a zinc salt of a paraphenylphenol/formaldehyde condensate, but it has not yet improved both color development and weather resistance, and there is a strong desire for improvements in color developers. As a result of the inventors' research in view of the above situation,
It has been found that by adding propane derivative phenols to a phenol resin, a color developer with extremely excellent color development and weather resistance can be obtained. That is, the present invention relates to a compound represented by the following general formula [] (R: hydrogen, alkyl group, phenyl group, aralkyl group, sulfonic acid group, carboxylic acid group, carboxylic acid ester group, halogen) Phenol resin (A) obtained by reaction with aldehydes and the following general formula [] The present invention relates to a novel color developer for pressure-sensitive recording paper, which contains as an essential component one or more of the propane derivatives (B) represented by the following formula and has extremely excellent color development and weather resistance. The compound represented by the above general formula [] constituting the phenolic resin (A) used in the present invention is p-
Cresol, p-ethylphenol, p-propylphenol, p-secondary-butylphenol, p-tertiary-butylphenol, p-amylphenol, p-cyclohexylphenol, p-heptylphenol, p-tertiary-butylphenol
Octylphenol, p-dodecylphenol,
p-nonylphenol, p-phenylphenol, p-cumylphenol, p-chlorophenol, p-bromophenol, p-phenolsulfonic acid, p-phenolcarboxylic acid, p-phenolcarboxylic acid ester, etc. They are para-substituted phenols and phenols, and one or more of these are used. These compounds are preferably p-phenylphenol, p-tert-butylphenol, p-tert-octylphenol. More preferably p-phenylphenol
50 to 95% by weight and 5 to 50% by weight of p-tert-butylphenol and/or p-tert-octylphenol. The aldehydes used in the present invention include formaldehyde (formalin, paraformaldehyde, formaldehyde gas), acetaldehyde, butyraldehyde, and the like, with formaldehyde being common. The phenolic resin (A) is a novolac-type phenolic resin obtained by reacting one or more of the para-substituted phenols and phenols with the aldehyde in the presence of a catalyst, and has a melting point of 5 to 170°C. . The phenolic resin (A) may be a co-condensation resin of two or more of the above phenols, or a mixture of one or more resins of different phenols obtained from one of the above phenols. The propane derivative phenols (B) represented by the above general formula [] used in the present invention are 4,
4'-dihydroxydiphenyl-2,2'-propane(a), 2,4'-dihydroxydiphenyl-
2,2'-propane (b) and 2,2'-dihydroxydiphenyl-2,2'-propane (c), and one or more of these is used. In the present invention, the blending ratio of the phenol resin (A) and the propane derivative phenols (B) may be any value, but preferably 5 to 5 parts by weight of (B) to 100 parts by weight of (A).
It contains 300 parts by weight, more preferably 10 to 200 parts by weight. If the amount of (B) present is small, the pressure-sensitive recording paper using it as a color developer will not have sufficient weather resistance, and if the amount is large, the color development will be insufficient. One type of propane derivative phenol (B) is sufficient, but it is preferable to have two or more types,
Furthermore, three types were added (a) 40 to 95% by weight, (b) 2 to 50% by weight, and
(c) Most preferably used in a proportion of 0.2 to 50% by weight. The method for producing the color developer of the present invention includes one or more phenolic resins (A) and propane derivative phenols.
Either a method of mixing one or more of (B) in powder form or a method of melting and mixing both under heating may be used. The color developer component thus obtained is in solid form. This is usually wet-pulverized in water using a wet-pulverizer such as an attriter or a sand grinder in the presence of a surfactant, a dispersant, etc. as necessary to form a dispersion liquid, which is a color developer dispersion for pressure-sensitive recording paper. Adjust. The method of mixing the phenolic resin (A) and the propane derivative phenols (B) in the above-mentioned wet grinder can be used. Further, it may be used by dispersing or dissolving in a solvent other than water, or by mixing the two at the time of dispersion or dissolution. The above color developer dispersion is mixed with adhesives, inorganic or organic pigments, pigment dispersants, optical brighteners, antifoaming agents, viscosity modifiers, anti-dusting agents, lubricants, waterproofing agents, etc. for coating. Prepare the liquid. This coating liquid is applied to paper or sheets using a roll coater or the like, and dried to obtain a recording paper or recording sheet having the color developer layer of the present invention on its surface. The solvent used in the above-mentioned dispersion or solution is one of water, alcohols, esters, ketones, aromatics, or high-boiling solvents, or a mixture thereof. For example, (1) polyethylene glycol type (ester type, ether type or alkylphenol type)
nonionic surfactants such as partial esters of polyhydric alcohols such as sorbitan esters, (2) alkali metal salts of formalin condensates of naphthalene-sulfonic acids, oligostyrene sulfonates, maleic acid-cocondensates; (3) Synthetic and natural anionic surfactants such as lignin sulfonates, and (3) inorganic ionic surfactants such as polyphosphates such as sodium metaphosphate and sodium pyrophosphate. good. Furthermore, a water-soluble polymer compound may be used as a protective colloid agent. Examples of adhesives added to the coating solution containing the color developer of the present invention include casein, starch, gum arabic,
These include synthetic resins such as gelatin, carboxymethyl cellulose, polyvinyl alcohol, water-soluble polymer polysaccharides, styrene-butadiene latex, hydroxyethyl cellulose, vinyl acetate polymer, melamine resin, sodium polyacrylate, and polyester resin. In addition, inorganic substances such as kaolin, bentonite, acid clay, talc, calcium carbonate, barium sulfate, aluminum oxide, titanium oxide, zinc oxide, polystyrene, polyurethane resin, melamine resin, urea resin, polyacrylic acid resin, polyester resin, phenolic resin , epoxy resin, petroleum resin, xylene resin, and other organic materials are used as fillers. As dispersants for these fillers, polyphosphates such as sodium metaphosphate and sodium hexametaphosphate, sodium polyacrylate, and the like are used. By using the color developer of the present invention, a pressure-sensitive recording paper with extremely excellent color development and weather resistance can be obtained. The reason why a color developer containing a propane derivative phenol (B) as an essential component in a phenolic resin (A) improves color development and weather resistance at the same time, especially when using propane derivatives, which do not exhibit any effect with each component alone. Among the phenols (B), three specific substances are phenolic resins.
The reason why the presence of (A) significantly improves color development and weather resistance at the same time is still unclear, but in the case of color development, it is probably the propane derivative phenols (B) that have the same effect as the phenol resin (A) and the composition of the present invention. It is thought that this is because by coexisting within this range, the phenolic resin has a coloring ability, and the phenolic resin also becomes easily soluble in the solvent containing the coloring agent, thereby significantly improving the coloring speed and coloring density. In addition, in the case of improving weather resistance, propane derivative phenols have a stable molecular structure, so when added to a phenolic resin (A) that has a chemical structure that easily resonates with sunlight energy, when the phenol resin (A) resonates. , molecular collisions occur, which seems to have the effect of inhibiting resonance. This is considered to be the reason why weather resistance such as yellowing resistance and fading resistance is also significantly improved if this is within the range of the composition of the present invention. Examples of the present invention will be described below, but the present invention is not limited to these examples. All "parts" and "%" herein indicate "parts by weight" and "% by weight" unless otherwise specified. Synthesis Example 1 500 parts of p-phenylphenol, 124 parts of 37% formalin, 100 parts of benzene, and 5 parts of oxalic acid were placed in a reaction vessel and reacted under reflux at 84°C for 10 hours. Thereafter, the water was dehydrated and the solvent removed under vacuum, and when the internal temperature was raised to 180°C, it was taken out of the pot. 512 parts of a solid condensate (X) having a yellowish brown color and a melting point of 82°C was obtained. Synthesis Example 2 350 parts of p-tert-octylphenol,
150 parts of phenol, 37% formalin 184 parts, 20%
25 parts of an aqueous sodium hydroxide solution and 300 parts of water were placed in a reaction vessel and refluxed at 97°C for 3 hours. Thereafter, the pH was adjusted to 5 with concentrated sulfuric acid. Next, 2 parts of concentrated hydrochloric acid were added to this, and the mixture was refluxed at 97°C for 1 hour. Afterwards, the water was dehydrated under vacuum, and when the internal temperature was raised to 180°C, the pot was taken out. 510 parts of a solid condensate (Y) having a yellowish brown color and a melting point of 84°C was obtained. Synthesis Example 3 350 parts of p-tert-octylphenol,
150 parts of phenol, 184 parts of 37% formalin, 25 parts of a 20% aqueous sodium hydroxide solution and 300 parts of water were placed in a reaction vessel and refluxed at 97°C for 3 hours. Thereafter, the pH was adjusted to 6 with concentrated sulfuric acid. Next, 2 parts of concentrated hydrochloric acid were added to this, and the mixture was refluxed at 97°C for 1 hour. After that, it was dehydrated under vacuum, and when the internal temperature was raised to 180°C, it was returned to normal pressure. To this was added 170 parts of 4,4'-dihydroxydiphenyl-2,2'-propane, and the mixture was melt-mixed. After the contents became homogeneous, it was taken out of the pot to obtain 675 parts of a brown solid condensate (Z) with a melting point of 78°C. Example 1 The above solid condensate (X) was pulverized with a hammer mill to an average particle size of 100 μm. 100 parts of this powder and 50 parts of fine powder of 4,4'-dihydroxydiphenyl-2,2'-propane having the same average particle size were placed in a V-type blender and dry blended for 1 hour. I took it out. In this way, a uniform fine powder color developer component () was obtained. 40 parts of this color developer component (), 1 part of anionic surfactant ("Orotan"731; manufactured by Rohm and Haas), 0.1 part of PVA powder and 58.9 parts of water were charged into an attritor, and wet-pulverized for 8 hours. A dispersion liquid in which the particle size of the mixture was 5 microns or less was obtained. This dispersion liquid was charged into an experimental mixer according to the formulation shown in Table 1, and mixed uniformly for 1 hour to prepare a coating liquid. The coating amount of this coating liquid is 5g/m ²
(dry weight) to obtain a recording sheet having a color developer layer on the surface. Example 2 100 parts of fine powder of the solid condensate (X) of Example 1,
Fine powder of 4,4'-dihydroxydiphenyl-2,2'-propane with a similar average particle size to this one.
22.5 parts, 2,4'-dihydroxydiphenyl-
5 parts of 2,2'-propane and 2.5 parts of 2,2'-dihydroxydiphenyl-2,2'-propane were placed in a V-type blender, dry blended for 1 hour, and then taken out. In this way, a uniform color developer component () was obtained. In the same manner as in Example 1, 40 parts of this color developer component () was added to 1 part of anionic surfactant ("Orotan" 731).
0.1 part of PVA powder was charged into an attritor together with 58.9 parts of water and wet-pulverized for 8 hours to obtain a dispersion having a particle size of 5 microns or less. Example 1 below
A recording sheet having a color developer layer on the surface was obtained in the same manner as above. Example 3 The above solid condensate (Z) was finely ground to an average particle size of 100 μm using a hammer mill to obtain a color developer component (2).
40 parts of this color developer component () was added to 1 part of anionic surfactant ("Orotan" 731) in the same manner as in Example 1,
0.1 part of PVA powder was charged into an attritor together with 58.9 parts of water and wet-pulverized for 8 hours to obtain a dispersion having a solid particle size of 5 microns or less. Thereafter, a recording sheet having a color developer layer on the surface was obtained in the same manner as in Example 1. Example 4 16 parts of the solid condensate (X) fine powder of Example 1 was mixed with an anionic surfactant ("Olotane") in the same manner as in Example 1.
731) and 0.1 part of PVA powder were charged into an attritor with 58.9 parts of water and wet-pulverized for 3 hours. Here, 4,4′- with the same particle size as the solid condensate (X)
Dihydroxydiphenyl-2,2'-propane
20.4 parts, 2,4'-dihydroxydiphenyl-
After sequentially adding 1.2 parts of 2,2'-propane and 2.4 parts of 2,2'-dihydroxydiphenyl-2,2'-propane, wet milling was continued for an additional 5 hours. In this way, a dispersion containing a color developer component () having a particle size of 5 μm or less was obtained. Thereafter, a recording sheet having a color developer layer on the surface was obtained in the same manner as in Example 1. Comparative Example 1 Average particle size of solid condensate (X) with a hammer mill
It was finely ground to 100μ to obtain a color developer component (2). In the same manner as in Example 1, 40 parts of this color developer component () was mixed with 1 part of anionic surfactant ("Orotan" 731) and PVA.
0.1 part of the powder was charged into an attritor together with 58.9 parts of water and wet-pulverized for 8 hours to obtain a dispersion having a solid particle size of 5 μm or less. Thereafter, a recording sheet having a color developer layer on the surface was obtained in the same manner as in Example 1. Comparative Example 2 The average particle size of the solid condensate (Y) was determined using a hammer mill.
It was finely pulverized to 100μ to obtain a color developer component (). In the same manner as in Example 1, 40 parts of this color developer component () was mixed with 1 part of anionic surfactant ("Olotane" 731),
0.1 part of PVA powder was placed in an attritor with 58.9 parts of water and wet-pulverized for 8 hours until the particle size of the solid was 5μ.
The following dispersion was obtained. Thereafter, a recording sheet having a color developer layer on the surface was obtained in the same manner as in Example 1. Comparative Example 3 A finely powdered color developer component (4,4'-dihydroxydiphenyl-2,2'-propane pulverized with a hammer mill to an average particle size of 100μ) as a color developer component.
A recording sheet having a color developer layer on the surface was obtained in the same manner as in Comparative Example 2 except that . Comparative example 4 4,4'-dihydroxydiphenyl-2,
22.5 parts of 2'-propane, 5 parts of 2,4'-dihydroxydiphenyl-2,2'-propane, 2,2'-dihydroxydiphenyl-2,2'-propane
2.5 parts of each were pulverized with a hammer mill to an average particle size of 00μ, placed in a V-type blender, dry blended for 1 hour, and then taken out. A recording sheet having a color developer layer on the surface was obtained in the same manner as in Comparative Example 2 except that this finely powdered color developer component (2) was used as the color developer component. Performance test method (a) Color development: A color development sheet containing crystal violet lactone was overlaid on the above recording sheet, and color was developed using an electric typewriter. The speed of color development was measured in 60 seconds, and the degree of color development was measured after 60 minutes using a reflection color difference meter (manufactured by Nippon Denshoku). The results are shown in reflectance (%), and the lower the value, the higher the color density. (b) Brown resistance: The recording sheet colored in the above (a) was irradiated with sunlight for 3 hours. The grades were rated ◎, ○, △, and × in descending order of the degree of browning. (c) Yellowing resistance: The uncolored recording sheet was exposed to sunlight for 3 hours. In descending order of degree of yellowing: ◎,
It was marked as ○, △, and ×. The results are shown in Table 2. As can be seen from this, the recording sheet having the color developer layer according to the present invention on its surface can reliably exhibit the effects of the essential components.

【table】

[Table] (Note) (B)/(A) indicates the weight ratio of propane derivative phenols (B) to phenol resin (A).

Claims (1)

[Claims] 1. A phenolic resin (A) obtained by the reaction of a compound represented by the following general formula [] with an aldehyde. Propane derivative phenols (B) represented by the following general formula [] (R: hydrogen, alkyl group, phenyl group, aralkyl group, sulfonic acid group, carboxylic acid group, carboxylic acid ester group, halogen) A novel pressure-sensitive recording paper color developer containing one or more of the following as essential components. 2. The pressure-sensitive recording paper color developer according to claim 1, which contains 10 to 200 parts by weight of propane derivative phenols (B) per 100 parts by weight of phenol resin (A). 3. The pressure-sensitive recording paper color developer according to claim 1 or 2, wherein the propane derivative phenol (B) is 4,4'-dihydroxydiphenyl-2,2'-propane. 4. The pressure-sensitive recording paper color developer according to claim 1 or 2, wherein the propane derivative phenol (B) is 2,4'-dihydroxydiphenyl-2,2'-propane. 5. The pressure-sensitive recording paper color developer according to claim 1 or 2, wherein the propane derivative phenol (B) is 2,2'-dihydroxydiphenyl-2,2'-propane. 6 Propane derivative phenols (B) are 4,4'-dihydroxydiphenyl-2,2'-propane
(a), 2,4′-dihydroxydiphenyl-2,
Claim 1 which is a mixture of 4'-dihydroxydiphenyl-2,2'-propane (b) and 2,2'-dihydroxydiphenyl-2,2'-propane (c) Or the pressure-sensitive recording paper color developer described in item 2. 7. Claim 6, wherein the mixture comprises (a) 40-95% by weight, (b) 2-50% by weight, and (c) 0.2-50% by weight.
A color developer for pressure-sensitive recording paper as described in Section 1.