JPS62176875A - Color developing sheet for pressure-sensitive copy paper - Google Patents

Abstract

PURPOSE:To obtain a color developing sheet for pressure-sensitive copy paper generating no yellowing due to light and gas such as nitrogen oxide in air, imparting a color image stable against light and a plasticizer and generating no lowering in developed color density and having good water resistance, by having a metallized substance of a copolycondensation resin consisting of salicylic acid and alpha,alpha'-dialkoxy-p-xylene contained as a developer. CONSTITUTION:A copolycondensation resin consisting of salicylic acid and alpha,alpha'-dialkoxy-p-xylene is obtained by reacting salicylic acid with alpha,alpha'-dialkoxy-p- xylene at 110 deg.C or more in the presence of an acid catalyst without almost generating corresponding side-reaction such as esterification reaction. A metallized substance of this salicylic acid copolycondensation resin is prepared by reacting an alkali metal salt of this resin and a water-soluble multivalent metal salt in water or in a solvent capable of dissolving both components. As the metal of the metallized substance, zinc is especially effective. As a method for preparing a color developing sheet for pressure-sensitive copy paper, there is the developer coating method or a method for internally adding the coupler in a paper stock during a papermaking process.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a color developer sheet for pressure-sensitive copying paper, and more specifically, a novel metalized salicylic acid cocondensation resin is used as a color developer. This invention relates to a color developer sheet for pressure-sensitive copying paper.

(Prior Art) Pressure-sensitive copying paper is also called carbonless paper, and is a copying paper that develops color by mechanical or impact pressure, such as when writing or using a typewriter, and can make multiple copies at the same time. There are so-called transfer-type papers and those called single color-forming papers, and their color-forming mechanism is based on a color-forming reaction between an electron-donating colorless dye and an electron-accepting color developer. Taking a transfer type pressure-sensitive copying paper as an example, this will be explained as shown in FIG. 1 as follows.

On the back side of the top paper 1 and the middle paper 2, microcapsules 4 with a diameter of several microns to more than ten microns are applied, which are made by dissolving a colorless pressure-sensitive dye in non-volatile oil and wrapping it in a polymer film such as gelatin. has been done. The surfaces of the middle paper 2 and the top paper 3 are coated with a paint containing a color developer 5 which has the property of causing a reaction and color development when it comes into contact with the above-mentioned pressure-sensitive dye. To make a copy, press top - (middle) - (middle)
- If you stack them in the order shown below (the dye-containing coated surface and the developer-containing coated surface face each other) and apply local pressure such as writing pressure 6 or typing pressure, the capsule 4 in that area will break and the pressure-sensitive dye A copy record is obtained by transferring the solution to the color developer 5.

As an electron-accepting color developer, m usp 2,712.5
(2) Substituted phenols and diphenols disclosed in Japanese Patent Publication No. 40-9309, disclosed in +31 Japanese Patent Publication No. 42-20144. p-2 substituted phenol-formaldehyde polymer, (4) Japanese Patent Publication No. 1987-1
Aromatic carboxylic acid metal salts disclosed in Japanese Patent Publication No. 0856 and Japanese Patent Publication No. 52-1327 have been proposed, and some of them have been put into practical use.

The performance conditions that a color developer sheet should have include not only excellent coloring properties that remain unchanged immediately after sheet production and even after long-term storage, but also little yellowing during storage and exposure to sunlight and other radiation, and a color image that is robust and resistant to radiation. Examples include not easily disappearing or discoloring due to water or plasticizers.

Conventionally proposed color developers and sheets coated with them have advantages and disadvantages in terms of performance. For example, inorganic solid acids are inexpensive, but they absorb gas and moisture in the air during storage, resulting in yellowing of the paper surface. p-phenylphenol-novolak resin, which is most commonly used as a p-1 substituted phenolic formaldehyde polymer, causes a decrease in coloring performance and poor coloring performance, and substituted phenols have insufficient coloring properties and low density of colored images. Although the coloring property is excellent, the coated paper turns yellow when exposed to sunlight or during storage (particularly due to heptase oxides in the air), and the colored image fades significantly. Further, although aromatic carboxylic acid metal salts have good coloring properties, yellowing properties, and fading properties due to light, their resistance to water or plasticizers is still not sufficient.

(Problems to be Solved by the Invention) An object of the present invention is to provide a color developer sheet for pressure-sensitive copying paper using a novel color developer that improves the above-mentioned drawbacks.

(Means for Solving the Problems) The present inventors have completed the present invention as a result of intensive studies to achieve the above object.

That is, the present invention provides salicylic acid and α,α'-dialkoxy-
This color developer sheet for pressure-sensitive copying paper is characterized in that it contains a metallized co-condensed resin consisting of p-xylene as a color developer.

The color developer sheet using the novel color developer of the present invention has the same or better color development property than the color developer sheet using an inorganic solid acid or p-phenylphenol novolac resin, and has color development properties. is resistant to fading easily due to water, plasticizers, and light.

Furthermore, yellowing caused by sunlight irradiation is improved, and in particular, resistance to yellowing caused by nitrogen oxides in the air is greatly improved, and it has the advantage of being able to provide a color developing sheet at a low cost that is extremely convenient for handling and storage.

The salicylic acid cocondensation resin used in the present invention is a novel resin that has never been produced before.

α, α゛dialkoxy ρ-xylene, which is an essential component of the cocondensation resin of the present invention, gives the corresponding phenolic resin by reaction with a phenolic compound, and this resin is further reacted with a basic compound such as hexamethylenetetramine. It is used as a so-called thermosetting polymer composition, which is cured by heating (Japanese Patent Publication No. 47-15111).

However, these thermosetting polymer compositions use carbolic acid, alkylphenols, phenylphenols, para-aminophenol, pyrogallol, and phloroglycitol as phenolic compounds;
Nothing is known about those reacted with salicylic acid. This means that when a phenol compound and α, α°-dialkoxy p-xylene are reacted under an acidic catalyst,
Alcohol is produced by the dealcoholization reaction, but when a phenol compound containing an organic carboxylic acid, i.e., salicylic acid, which is a component of the present invention, reacts with the alcohol produced under an acidic catalyst, salicylic acid esters and a mixture of these resins are produced. It is thought that this has not been considered yet because it is easily expected that it would be difficult to obtain the intended target product.

However, the present inventors surprisingly found that when salicylic acid and α,α1-dialkoxy p-xylene were reacted at a reaction temperature of 110°C or higher in the presence of an acid catalyst, there were almost no corresponding side reactions such as esterification reactions. It has been found that the salicylic acid resin of the present invention can be obtained without causing this problem.

In the present invention, when the reaction is carried out at a temperature of 110°C or higher, when the number of carbon atoms in the alkyl group is 5 or less in various α,α”-dialkoxy-p-xylene, the reaction is rapid and the esterification reaction is also prevented. In addition, in a butyl group with 4 carbon atoms, t
The reaction of er t-butyl group tends to be slow.

Therefore, α, α giving the cocondensation resin used in the present invention
The 1-dialkoxy p-xylene is preferably α,α1-dimethoxy-p-xylene, α,α1-jethoxy-1-1-xylene, α,αゝ-di-n-propoxy-p-xylene, α,α゛-isopropylene. poxy p--
Xylene, α, α9-di-n-butoxyp-xylene, α, α゛-di-5ee-butoxy-ρ-xylene, α
, α°-diisobutyl-ρ-xylene, etc., but are not limited to these.

α in the production of the cocondensation resin used in the present invention.

The amount of α゛-dialkoxy p-xylene used is 0.1 to 1.0 molar ratio, preferably 0.
．． The molar ratio is 3 to 0.8.

Further, the reaction temperature needs to be 110°C or higher; if it is lower than 110°C, the reaction will be extremely slow and side reactions such as esterification reactions will increase. In addition, in order to shorten the reaction time as much as possible, approximately 130 to 240
A temperature range of °C is preferred. Reaction time is 1 to 20 hours. Acid catalysts include inorganic or organic acids, in particular mineral acids, such as hydrochloric acid, phosphoric acid, sulfuric acid or formic acid, or Friedel-Crach type catalysts such as zinc chloride, stannic chloride, ferric chloride. Organic sulfonic acids such as methanesulfonic acid or ρ-toluenesulfonic acid may be used alone or in combination. The amount of catalyst used is salicylic acid and α, α′
- from about 0.01 to the total weight of dialkoxy-p-xylene
It is 5% by weight.

A general method for producing the resin used in the present invention is as follows:
Predetermined amounts of salicylic acid, α, α°-dialkoxy p-xylene, and a catalyst are added simultaneously, and the mixture is heated to a predetermined temperature for reaction. The alcohol produced as the reaction progresses is trapped outside the system. If necessary, trace amounts of alcohol remaining in the system are removed from the system using nitrogen.

After the reaction is completed, the contents are discharged, cooled, and then pulverized to obtain the desired product. Furthermore, in order to obtain a resin with a relatively low molecular weight composition, if the molar ratio of α, α°-dialkoxy ρ-xylene used is reduced, unreacted salicylic acid remains, so as a method to remove it, the resin Methods include washing with hot water or dissolving in an organic solvent such as methyl isobutyl ketone or cyclohexanone and washing with hot water.

Several known methods can be applied to produce the metallized product from the salicylic acid cocondensation resin thus produced.
For example, it can be produced by reacting the alkali metal salt of the present resin with a water-soluble polyvalent metal salt in water or a solvent in which both are soluble.

That is, after reacting an alkali metal hydroxide, carbonate, alkoxide, etc. with a resin to obtain an alkali metal salt of the resin or an aqueous solution, alcohol solution, or water-alcohol mixed solution of the alkali metal salt, a water-soluble polyhydroxide is prepared. This is a method of producing it by reacting valent metal salts. It is desirable to react about 0.5 to 1 gram equivalent of water-soluble polyvalent metal salt per mole of salicylic acid in the resin.

Alternatively, it can be produced by mixing a resin with a polyvalent metal salt of an organic carboxylic acid such as formic acid, acetic acid, propionic acid, valeric acid, caproic acid, stearic acid or benzoic acid, and heating and melting the mixture. In some cases, a basic substance such as ammonium carbonate, ammonium bicarbonate, ammonium acetate, or ammonium benzoate may be further added and melted by heating.

Furthermore, we use resins and polyvalent metal carbonates, oxides, and hydroxides, and combine basic substances such as ammonium formate, ammonium acetate, ammonium caproate, ammonium stearate, and ammonium organic carboxylates such as ammonium benzoate. Can be manufactured by heating and melting.

When producing a metallized resin by heating and melting, the melting temperature is usually 100 to 180°C, and the reaction time depends on the resin composition, melting temperature, type of polyvalent metal salt, and amount used.
It takes about 1 to several hours. Regarding the amount of polyvalent metal salt used, the amount of metal is 1 per total weight of resin! I (1% to about 20
It is desirable to use organic carboxylates, carbonates, oxides, and hydroxides of polyvalent metals so that heavy reduction χ exists.

There is no particular restriction on the amount of the basic substance used, but it is usually used in an amount of 1 to 15% by weight based on the total weight of the resin. When using a basic substance, it is more preferable to mix it with a polyvalent metal salt beforehand.

The metal of the metallized salicylic acid cocondensation resin used in the present invention includes metals other than alkali metals such as lithium, sodium, and potassium. Preferred polyvalent metals include magnesium, aluminum, copper, zinc, and tin. , barium, cobalt and nickel.

Among these, zinc is particularly effective.

The color developer used in the present invention may be used in combination with known color developers, such as inorganic solid acids such as activated clay, organic polymers such as phenol-formaldehyde resin, or metal salts of aromatic carboxylic acids.

The color developer used in the present invention further comprises at least one of oxides, hydroxides or carbonates of polyvalent metals selected from the group consisting of zinc, magnesium, aluminum, lead, titanium, calcium, cobalt, nickel, manganese and barium. 1
You may use more than one species together.

The method for preparing the color developer sheet for pressure-sensitive copying paper of the present invention includes a method in which a water-based paint using an aqueous suspension of fl + color developer is applied to a support such as paper; (2) color development at the time of paper making; Any method can be used, such as (3) a method in which a color developer is dissolved or suspended in an organic solvent and applied to a support.

When preparing a paint, kaolin clay, calcium carbonate, starch, synthetic and natural latex, etc. are distributed to create a paint with appropriate clay and coating suitability. The proportion of the color developer component in the paint is 10 to 70% of the total solid content.
z is desirable; if the proportion of the color developer component is less than 10%, sufficient color development cannot be achieved, and if it is more than 70%, the paper properties of the color developer sheet will deteriorate. The amount of paint applied is 0 in terms of dry weight.
．． 5g/cm! Above, preferably 1 to 10 g/cd.

In the color developer sheet for pressure-sensitive copying paper of the present invention, the amount of color developer component and paint applied is small, and the concentration, viscosity, etc. of the paint can be changed over a relatively wide range, so on-machine coating, Off-machine coating is also possible, which brings great benefits not only in terms of performance but also in the pressure-sensitive paper manufacturing process.

(Functions and Effects) The present invention provides a color developer sheet for pressure-sensitive paper containing a metallized product of a novel co-condensed resin consisting of salicylic acid and α,α'-dialkoxy-p-xylene as a color developer.

The color developing sheet of the present invention does not cause yellowing due to light or gases such as nitrogen oxides in the air, has a stable color image against light and plasticizers, does not cause a decrease in color density, and is water resistant. Since it also has good properties, it has become possible to expand its use to applications for which conventional products were unsuitable because long-term storage stability is required, and its practical significance is extremely large.

(Example) Hereinafter, the method of the present invention will be explained in detail with reference to Examples.

The performance of the pressure-sensitive copying paper developer sheet was measured as follows.

1. Color development rate and density (conducted in a thermostatic chamber at 20°C and 65χR11) (1) Commercial blue coloring paper containing crystal violet lactone (CVL) as the main pressure-sensitive dye (N
(2) Using commercially available black coloring paper (KW-40T manufactured by Jujo Paper Industries) containing 3-diethylamino-6-methyl-7-phenylamino-fluoran (ODB) as the main pressure-sensitive dye, water-based paint was applied. The re-applied side of the color developing sheet (lower paper) that was coated with is placed on top of the sheet, and the color is developed by pressing with an electronic typewriter.

The color is measured at two points, 1 minute and 30 seconds after stamping and 24 hours later, and displayed as a Y value.

2. Light fastness of color image The color developing sheet developed using method 1 was tested on a carbon arc fade meter (Suga Test Instruments!!) for 2 hours (and 4 hours).
time) and the concentration after irradiation was expressed as a Y value using a Σ-80 color difference meter.

The lower the Y value and the smaller the difference from the pre-test value, the less fading caused by light, which is preferable.

3. Prepare melamine/formaldehyde resin membrane microcapsules with an average particle size of 5.0μ with plasticizer-resistant dioctyl phthalate (DOP) as the core material, and apply a coating liquid containing a small amount of starch binder using an air knife coater. DOP microcapsule coating was prepared by coating and drying on top M paper so that the dry coating amount was 5 g/. After facing the DOP microcapsule coated paper and the coloring surface of the color developing sheet developed in step 1,
The DOP is passed through a super calender roll having a linear pressure of 00 kg/ca+ to uniformly infiltrate the coloring surface.

The concentration one hour after the test is expressed as a Y value using a Σ-80 color difference meter. The lower the Y value and the smaller the difference from the pre-test value, the better the plasticizer resistance of the colored image.

4. Water resistance of colored image The color developing sheet developed by the method of 1 was immersed in water for 2 hours, and changes in the density of the colored image were observed with the naked eye.

5. Yellowing of developer sheet (5-1) Yellowing according to No. 1 JIS L-1055 (color developer sheet based on nitrogen oxide gas fastness test method for dyed products and dyes) laNOl
The sample was stored for 1 hour in a sealed container in an atmosphere of NO generated by the reaction between (sodium nitrite) and IhPOa (phosphoric acid), and the degree of yellowing was examined.

One hour after the end of the test, the WB value is displayed using a Σ-80 color difference meter. -The larger the B value and the smaller the difference from the WB value of the untested sheet, the less yellowing in the atmosphere.

(5-2) Yellowing due to light The color developing sheet is irradiated with a carbon arc fade meter (manufactured by Suga Test Instruments) for 4 hours, and after the test, it is displayed as a WB value using a Σ-80 color difference meter. The larger the -B value and the smaller the difference from the -B value of the untested sheet, the smaller the yellowing caused by light irradiation.

Cocondensation resins consisting of salicylic acid and α,α°-dialkoxy p-xylene and metallized products thereof in the present invention were manufactured according to Synthesis Examples 1 to 11.

Synthesis Example 1 27.6 g (0.2 mol) of salicylic acid, 23.2 g (0.14 mol) of α, α°-dimethoxy p-xylene, and 0.1 g of p-toluenesulfonic acid as a catalyst were charged into a glass reactor. When condensation was carried out at a reaction temperature of 170 to 180°C for 3 hours, 8 g of methanol was distilled out. Next, at the same temperature, it was immediately poured into an enamel shallow dish and left to stand, and the resin-like product solidified and a reddish-brown transparent product was obtained. 40 g of resin was obtained. The softening point of the obtained resin was measured using a ring and ball softening point measuring device according to JIS-2548 and found to be 140°C.

The IR analysis results (measured by the KBrBr method) are shown in Figure 2.

Synthesis Example 2 27.6 g (0.2 mol) of salicylic acid, 10 g (0.06 mol) of α, α゛-jetoxy p-xylene, and 0.75 g of anhydrous zinc chloride as a catalyst were charged into a glass reactor, and the reaction temperature was 160 mol. Condensation was carried out at ˜170° C. for 4 hours. Next, the internal temperature was cooled to 100°C and methyl isobutyl ketone 7
Add 0 ml and dissolve, then add 500 ml of warm water and 95 ~
Stir at 100°C for 2θ minutes and remove the aqueous layer. This hot water wash,
The liquid separation operation was repeated two more times to remove unreacted salicylic acid. Then, the solvent was distilled off and the condensate was cooled to obtain 18.4 g of a reddish-brown transparent resin. Softening point is 84
It was ℃.

Synthesis Examples 3 to 5 Synthesis examples except that the type of α,α'-dialkoxy-p-xylene, the molar ratio with salicylic acid, the type of catalyst used, and the reaction conditions in the condensation reaction were as shown in Table 1. A salicylic acid resin was obtained in the same manner as in 1.

Synthesis Example 6 The resin log obtained in Synthesis Example 1 was ground and dispersed in 100 g of a 2% caustic soda aqueous solution. When this dispersion was heated to a temperature of 70° C. while stirring, it was dissolved. Then, a solution prepared by dissolving 3.8 g of anhydrous zinc chloride (purity 90%) in 30 ml of water was added dropwise over 30 minutes while stirring while maintaining the temperature of the solution at 45 to 50°C.

A white precipitate was deposited, and after continued stirring at the same temperature for 2 hours, it was filtered, washed with water, and dried, resulting in a white powder of 11.5
I got g. This was a zinc salt of salicylic acid resin, and the zinc content was 15.2%.

Synthesis Example 7 Nickel chloride hexahydrate (purity 9) was used instead of anhydrous zinc chloride.
6%) was carried out in the same manner as in Synthesis Example 6 to obtain 11.5 g of pale green salicylic acid resin nickel salt powder.

Synthesis Example 8 Magnesium chloride ('4@4g) instead of anhydrous zinc chloride
The same procedure as in Synthesis Example 6 was carried out using 2.5 g of 5%) to obtain 10.5 g of white salicylic acid resin magnesium salt powder.

Synthesis Example 9 12.5 g of the resin obtained in Synthesis Example 2 was placed in a flask and heated to melt at a temperature of 150 to 160°C. Then, with stirring, 8.2 g of zinc benzoate and ammonium bicarbonate were added in advance. A mixture of 5 g was gradually added to the molten resin over 30 minutes. Thereafter, the mixture was stirred at a temperature of 155 to 165°C for 1 hour to complete the reaction.

After the reaction is completed, the molten resin is discharged, cooled, and then pulverized to obtain 18.5 g of powder of zinc benzoate modified salicylic acid resin.
I got it. The softening point of this zincide was determined according to JIS-2548.
When measured with a ring and ball softening point measuring device, it was 125°C.
Met.

Synthesis Example 10 4.4% zinc acetate per 10g of resin obtained in Synthesis Example 3
A heating reaction was carried out at 150 to 160°C using 6
During the reaction, the acetic acid produced was removed to the outside of the thread by bubbling nitrogen gas.

The obtained zinc acetate modified salicylic acid resin has a softening point of 13
After cooling at 9°C, it was ground into powder.

Synthesis Example 11 1.3 zinc acetate per 10g of resin obtained in Synthesis Example 5
A zinc-modified resin with a softening point of 118° C. was obtained in the same manner as in Synthesis Example 9 using a mixture of g and 2.4 g of ammonium acetate.
After cooling, it was ground into powder.

Examples 1 to 6 Using the metallized salicylic acid resins obtained in Synthesis Examples 6 to 11 as a color developer, suspensions were prepared by dispersing the following compositions using a sand grinding mill.

Color developer 6 parts by weight lOχ
Polyvinyl alcohol water content → night (Kuraray +1117)
3 ff (! fun water
22.5 parts by weight Next, a paint having the following composition was prepared using the suspended i1E liquid.

Suspension 10 parts by weight Light calcium carbonate 10 parts by weight Powder
0.8 parts by weight Synthetic rubber Latinx 0.8
Part by weight Water: 32.5 parts by weight The dry coating amount of these paints on high-quality paper is 5.0 to 5.5 g.
/n? It was coated and dried to obtain a color developing sheet.

Examples 7 to 8 Using the developer suspensions obtained in Synthesis Examples 6 and 9, paints having the following compositions were prepared.

Suspension 10 parts by weight Zinc oxide 2 parts by weight Calcium carbonate 8 parts by weight Starch 0.8 parts by weight Synthetic rubber latex 0.8 parts by weight Water
32.5 parts by weight of these paints were applied to high-quality paper so that the dry coating amount was 5.0 to 5.5 g/n (dry), and dried to obtain a color developing sheet.

Comparative example 1 p-phenylphenol 170g, 80% paraformaldehyde 22.5g, p-toluenesulfonic acid 2
．． 0 g and benzene 200 g are charged into a glass reactor, heated while stirring, and reacted at 70 to 80 ° C. for 2 hours while distilling the water produced by the reaction out of the system by azeotrope with benzene. After 0 reaction. 320 g of a lo% I-IJ aqueous solution of hydroxide was added, and benzene was distilled off by steam distillation. Next, after cooling, dilute sulfuric acid was added dropwise, and the precipitated p-phenylphenol formaldehyde polymer was collected by filtration, washed with water, and dried to obtain 176 g of white powder.

A color developer sheet was obtained using this p-phenylphenol formaldehyde polymer in the same manner as in the example.

Table 2 shows the performance evaluation results of the color developing sheets obtained in Examples 1 to 8 and Comparative Example 1.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the structure of pressure-sensitive copying paper. In FIG. 1, each symbol is as follows. 1. Top paper 2. Middle paper 3. Bottom paper 4. Microcapsules 5. Color developer 6. Pen pressure Figure 2 is a TR spectrum diagram of the salicylic acid resin produced in Synthesis Example 1. Patent applicant Mitsui Toatsu Chemical Co., Ltd. Engraving of drawings (no change in content) Drawing Drawing -1 Passage rate (%) Hand 3 sale (Ichisho 4 (method) % formula % 1. Indication of incident 1986 patent application No. 1ε027 No. 2, Name of the invention Color developer sheet for pressure-sensitive copying paper 3, Relationship with the person making the amendment Patent applicant address 3-2-5 Kasumigaseki, Chiyoda-ku, Tokyo Name (31
2) Mitsui Toatsu Chemical Co., Ltd. March 25, 1986 (
Shipping El) The drawing plan will be replaced with a separate drawing that is clearly drawn in Figure 1 and in which unnecessary ruled lines in the graph have been deleted in Figure 2. that's all

Claims (1)

[Claims] 1) A color developer sheet for pressure-sensitive copying paper, characterized in that it contains a metallized co-condensed resin consisting of salicylic acid and α,α'-dialkoxy-p-xylene.