JPH01283184A - Color developer for leuco dye - Google Patents

Abstract

PURPOSE:To enhance color formability, discoloration resistance and light fastness, by using a mixture of SiO2 and oxide of an element belonging to the Group IVb of the Periodic Table as a color developer. CONSTITUTION:As a color developer for a leuco dye, SiO2 is used and, in order to increase the acidity of SiO2, at least one or more kinds of oxide of an element belonging to the Group IVb of the Periodic Table such as TiO2 or ZrO2 is mixed with SiO2. Since the oxide of the element belonging to the Group IVb of the Periodic Table has high whiteness, a good image is obtained. For example, 20pts.wt. of SiO2 and 10pts.wt. of TiO2 are added to 50pts.wt. of a 5% aqueous polyvinyl alcohol solution, and ground and dispersed to prepare a color developer dispersion. This color developer dispersion is applied to wood free paper to prepare a color developing sheet. By this method, the color developer for the leuco dye excellent in color formability, discoloration resistance and light fastness and having high whiteness is obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to leuco dyes used in pressure-sensitive copying paper and heat-sensitive recording paper. This invention relates to a color developer for leuco dyes with a high degree of strength.

[Summary of the invention]

2. Description of the Related Art In recent years, with the rapid development of the information industry, pressure-sensitive copying paper and thermal recording paper, which can easily obtain recording output from information equipment terminals for industrial use, office use, etc., have been widely used.

The present invention improves color development and fastness by using a mixture of 5iQz and oxides of group Yb of the periodic table as a color developer for leuco dyes used in the pressure-sensitive copying paper and the heat-sensitive recording paper. Fading property.

The object of the present invention is to provide a color developer for leuco dyes that enables recording with excellent light resistance.

[Conventional technology]

Conventional color developers for leuco dyes include α-naphthol, β-naphthol, 2,2'-methylenebis(4-methyl-6-tertiary isobutylphenol), 2,2
'-Methylenebis(4-chlorophenol), 4-phenylphenol, 4-tertiarybutylphenol, 2.
2'-dihydroxydiphenol, 4,4'-secondary butylidenephenol, 4,4'-dichlorhexylidine diphenol, 4-hydroxydiphenoxide,
4,4'-isopropylidene diphenol, hydroquinone, 4-hydroxyacetophenol, 4,4'-isopylidene bis(2-tert-butylphenol)
, 4-tert-octylcatechol, novolak type phenolic resin, phenolic polymers and other phenolic compounds, salicylic acid, 3-(α-methylhen)salicylic acid, 3,5-di-α-α-methylhensylsalicylic acid, 3 -isopropylsalicylic acid, 3-chloro-5-(α
-methylbenzyl)salicylic acid, 3-phenyl-5-(
α・α-dimethylhensyl) salicylic acid, 3-hensylsalicylic acid, 3,5-ditertiarybutylsalicylic acid,
3-Cushabutylsalicylic acid, benzoic acid, terephthalic acid, 3,5-dimethyl-4-hydroxybenzoic acid, para-tertiarybutylbenzoic acid, 3-sec-butyl-
4 = Aromatic carboxylic acids such as hydroxybenzoic acid, trichlorobenzoic acid, 3-cyclohexyl-4-hydroxybenzoic acid, and these phenolic compounds, activated clay, acid clay, aluminum silicate, bentonite, acpal guide , solid acids such as colloidal silica, and organic acidic substances such as salts of aromatic carboxylic acids and polyvalent metals such as magnesium, aluminum, calcium, titanium, manganese, tin, and nickel are used.

[Problem to be solved by the invention]

However, when conventional organic compounds are used as color developers for leuco dyes, there is a problem in that the color development is not very good and the color fades. In addition, there were problems such as coloring due to light irradiation and severe yellowing caused by nitrogen compounds in the atmosphere. In addition, activated clay has a yellowish tinge, making it impossible to obtain good images.

Therefore, in order to solve these conventional problems, it is an object of the present invention to provide a color developer for leuco dyes that has excellent color development, excellent fading resistance, light resistance, and high whiteness. It is said that

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention uses SiOz as a color developer for leuco dyes, and furthermore, this SiO□
Si
By mixing O, the color development property is improved, and the fading resistance and light resistance are also improved. Furthermore, Tie.

Oxides of group IVb of the periodic table, such as ZrO and ZrO, have a high degree of whiteness and are therefore used to obtain good images.

〔Example〕

Examples of the present invention are shown below.

Example 1 Polyvinyl alcohol aqueous solution 5 with a concentration of 5% (W/W)
0 parts by weight, 20 parts by weight of 5iOt and 10 parts by weight of Ti0□ were added together and pulverized and dispersed for about 24 hours using a ball mill to obtain a color developer dispersion. This color developer dispersion was coated with a bar coater at 40 g/n? 20g/+yr on high quality paper
(dry weight) to obtain a color developing sheet for leuco dyes. This color developer sheet for leuco dyes was combined with pressure-sensitive copying paper using leuco dyes, weighing 120 kg.
The color was developed under a pressure of /cm and the density was measured. Furthermore, in order to examine the resistance to fading, the color density was measured 500 hours after color development.

The above measured values are shown in Table 1.

Example 2 Polyvinyl alcohol aqueous solution 5 with a concentration of 5% (W/W)
0 parts by weight, 20 parts by weight of S i Ox, Zr0°10
Parts by weight were added together and pulverized and dispersed for about 24 hours using a ball mill to obtain a color developer dispersion. A color developing sheet for leuco dye was prepared using the same method as in Example 1, and the same measurements as in Example 1 were performed.

The above measured values are shown in Table 1.

Example 3 Polyvinyl alcohol aqueous solution 5 with a concentration of 5% (W/W)
0 parts by weight, 20 parts by weight of 5iOz, 25 parts by weight of Tie,
5 parts by weight of ZrO@ were added thereto, and the mixture was pulverized and dispersed for about 24 hours using a ball mill to obtain a color developer dispersion. A color developing sheet for leuco dye was prepared using the same method as in Example 1.2, and the same measurements as in Example 1.2 were carried out.
The above measured values are shown in Table 1.

Comparative Example In order to compare with the above example, bisphenol A, which is one of the known color developers for leuco dyes, was measured in the same manner as in Example 1.2.3, and the measured values are shown in Table 1. show.

Table 1 [Effects of the invention] As described above, stow is used as a color developer for leuco dyes.
By using a mixture containing at least one type of oxide of group rVb of the periodic table, we can create a color developer for leuco dyes that has excellent color development, fade resistance, light resistance, and high white dust. can be provided.

that's all Applicant: Seiko Electronics Industries Co., Ltd.

Claims (1)

[Claims] A color developer for leuco dyes, characterized in that a mixture containing SiO_2 and at least one oxide of group IVb of the periodic table is used as a color developer for leuco dyes.