JPS60228187A - Pressure-sensitive copying paper - Google Patents

Abstract

PURPOSE:To provide a pressure-sensitive copying paper high in developed color density, having excellent weather resistance and less liable to be faded, wherein a specified polyphenol compound is used in combination with an inorganic solid acid or a phenolic resin, as a color developer. CONSTITUTION:The pressure-sensitive copying paper comprises (A) an inorganic solid acid, e.g., acid clay, or a phenolic resin, e.g., p-t-butylphenol-aldehyde resin, and (B) a polyphenol compound of the formula, wherein R is 1-18C alkyl, aryl or aralkyl, R<1> is H, 1-5C alkyl or aryl, R<2> is 1-5C alkyl or aryl, and n is a number of not less than 3 and represents an average degree of polymerization, in combination with each other as a color developer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to pressure-sensitive copying paper, and particularly to pressure-sensitive copying paper that has high color density and excellent weather resistance, that is, is resistant to fading.

More specifically, the present invention provides a pressure-sensitive copying paper using an inorganic solid acid or a phenolic resin as a color developer of the general formula (in the above formula, R is an alkyl group having 1 to 18 carbon atoms, an aryl group, an aralkyl group, R1 is hydrogen, an alkyl group having 1 to 5 carbon atoms, or an aryl group; R2 is an alkyl group having 1 to 5 carbon atoms or an aryl group; n is 3 or more and indicates the average degree of polymerization.

) The present invention relates to a pressure-sensitive copying paper characterized in that one or more polyphenol compounds represented by the following are used in combination.

In general, pressure-sensitive copying paper is a color-forming agent formed in microcapsules containing an electron-donating colorless basic dye solution and an electron-accepting acidic color developer capable of developing color on both sides of the paper. Alternatively, by applying pressure by writing or printing to the top and bottom sheets of paper, either by applying them on the same surface or separately, these microcapsules are broken down, and as a result, the color forming agent and the color developing agent are applied. Copying paper based on a coloring mechanism that develops color by reacting with an agent.

When using these conventional color developers, there are various factors that can cause problems. After that, there were drawbacks such as discoloration or fading over time.

Although a wide variety of principles, mechanisms, and manufacturing techniques for pressure-sensitive copying paper have been known, the present inventors have developed a pressure-sensitive paper based on the above-mentioned coloring mechanism for the purpose of preventing discoloration over time. After extensive research, we found that by coexisting one or more polyphenol compounds represented by the general formula (I) with inorganic solid acids or phenolic resins, which are currently commonly used as color developers, discoloration can be achieved. Preventive effect In particular, we have discovered that scales have an enhanced ability to prevent discoloration over time, and have completed the present invention.

The color formers used in the present invention include crystal violet lactone, malachite green lactone, benzoyl leucomethylene blue, 3, which are generally known as color formers.
-dialkylamino-7-diaμkylamylfluoran and the like are used, but are not limited thereto.

On the other hand, as a color developer, inorganic solid acids such as acid clay, activated clay, $1 zeolite, and bentonite, which have been conventionally used, and para-tert-butylphenolaldehyde resin, halaochnolaldehyde)'! Para-substituted arylphenolaldehyde resins such as paraphenylphenolaldehyde resin, paracumylphenolaldehyde resin, and halogenated phenolicaldehyde resins such as parachlorophenolaldehyde resin are used, but are not limited thereto.

The polyphenol compound of formula (I) of the present invention is a condensate of a substituted phenol and an aldehyde, do, or ketone, and n indicating the average degree of polymerization is 3 or more, particularly preferably 4 to B.
Use the one.

The polyphenol compound used in the present invention is produced, for example, by the method disclosed in Japanese Patent Publication No. 46-9941 or Japanese Patent Publication No. 39-16905. The molecular weight of this polyphenol compound is measured by the Last method, and the value of n can be calculated thereby.

Substituted phenols, which are one of the raw materials for producing polyphenol compounds, include methylphenol, ethylphenol, isopropylphenol, tertiary butylphenol, tertiary amylphenol, jI 3m octylphenol, nonylphenol, dotesylphenol, phenylphenol. Examples include phenols substituted at the alkyl, aryl, and aralkyl positions such as phenol, cumylphenol, benzylphenol, α-methylbenzylphenol, and phenethylphenol; Certain aldehydes or ketones include acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde, benzaldehyde, acetone, methyl ethyl ketone, methyl butyl ketone, ethyl butyl ketone, etc.
Of course, it is not limited to these.

Representative examples of specific polyphenol compounds of general formula ('I) are shown in Table 1 below, but the present invention is not limited thereto.

-Left below- Table 1 The proportion of the polyphenol compound used in the inorganic solid acid or phenol resin is 0 to 1 part by weight.
．． It is preferred to use 0.05 to 1 part by weight, preferably 0.1 to 0.6 part by weight of polyphenol compounds.

At this time, these color developers can also be used in combination with other conventional color developers other than those mentioned above.

The pressure-sensitive copying paper of the present invention itself is manufactured by a known method. For example, first, the color developing material is coated with a suitable adhesive (e.g., starch, polyvinyl alcohol, gum arabic, water-soluble polymers such as carboxymethyl cellulose, hydroxyethyl cellulose, and styrene-butadiene copolymer). , methyl methacrylate-butadiene copolymer, other acrylic polymers, etc.) and dispersed or dissolved in water or an organic solvent to form a coating liquid.

At this time, in addition to the above-mentioned ingredients, the coating liquid contains conventionally used additives such as calcium carbonate, talc, clay,
Fillers such as titanium oxide, calcium carbonate, magnesium carbonate, silica, aluminum silicate, sodium dioctyl succinate, sodium dodecylbenzene sulfonate, sodium lauryl sulfate, fatty acid metal salts, fatty acid amides such as ethylene vinyl fatty acid amide, paraffin wax, etc. Examples include dispersants, ultraviolet absorbers, antifoaming agents, waterproofing agents, etc., which can be appropriately selected and contained depending on the purpose.

Next, this coating liquid is applied to a high-quality paper, and the application amount is adjusted using an air knife coater to obtain a lower paper.

On the other hand, a top sheet for forming a colored image is prepared by coating one side of the top sheet with a dispersion of a color former dye microencapsulated by a coacervation method to form an appropriate amount of a microcapsule layer.

Other methods for microencapsulation include interfacial polymerization, In5Ltu method, and the like.

The pressure-sensitive copying upper sheet and lower sheet thus obtained are combined and printed under pressure using a typewriter or the like.

Next, the present invention will be explained with reference to Examples, but the present invention is not limited thereto.

In addition, parts mean parts by weight.

Example 1 1) Top paper 30 parts of crystal violet lactone is dissolved in 370 parts of alkylated naphthalene oil and microencapsulated by the facervation method to obtain a dispersion. This dispersion was applied to one side of the top paper with a weight of 40 g/m' to obtain a microcapsule layer with a dry weight of 4 g/m'.

2) Bottom paper Sodium hexametaphosphate 1 part Water 220-260 parts lO% polyvinyl alcohol solution 30 parts Zinc oxide 1
A mixed solution was prepared by adding the polyphenol compounds shown in Table 2 to a composition consisting of 100 parts of activated clay (Jilton), and then diluted with aqueous ammonia.
H9.5 was adjusted, and this was applied to 40 g/yr/high-quality paper using an air knife coater so that the coating amount was 7 g/m'' (solid weight).

The color-developing upper sheet and the color-developing lower sheet obtained in 1) and z) were combined and printed under pressure using a typewriter.

Table 2 shows the coloring performance of the coloring layer of the obtained recording form paper.

One or less margin one Table 2 Note (1) Immediately after color development, it was measured using a Macbeth densitometer.

Note (2) The concentration after being left at room temperature for one month was measured and compared with the concentration immediately after color development.

Example 2 The lower paper was prepared as follows.

Sodium hexametaphosphate 1 part Water 140-200 parts 10% polyvinyl alcohol solution a 3o parts Zinc oxide 1
A mixture was prepared by adding the polyphenol compounds shown in Table 3 to a composition consisting of 200 parts of a 25% p-phenylphenol resin dispersion, and the mixture was adjusted to pH 9 with aqueous ammonia.
, 5, and the coating amount was 7 g on 40 g/rd high-quality paper.
/m (solid weight parts) using an air knife coater. The color-developing lower sheet thus obtained was combined with the color-developing upper sheet prepared in Example 1, and pressure printing was performed using a typewriter.

The coloring performance of the obtained recording coloring layer is shown in Table 3.

- Margin 1 below Table 3 As shown above, pressure-sensitive copying paper with high color density and excellent weather resistance (no fading) by using the polyphenol compound of general formula (I) in combination with an inorganic solid acid or phenol resin is obtained.

Agent: Patent Attorney Masaru Takamiyagi

Claims (1)

[Scope of Claims] In pressure-sensitive copying paper using an inorganic solid acid or phenolic resin as a color developer, the general formula (in the above formula, R represents an alkyl group having 1 to 18 carbon atoms, an aryl group, or an aralkyl group)
R1 is hydrogen, an alkyl group having 1 to 5 carbon atoms, or an aryl group; R2 is an alkyl group having 1 to 5 carbon atoms or an aryl group; n
indicates an average degree of polymerization of 3 or more. ) A pressure-sensitive copying paper characterized in that it uses one or more polyphenol compounds represented by the following.