JPS6028677B2 - pressure sensitive recording paper - Google Patents

Description

[Detailed description of the invention] The present invention relates to pressure sensitive recording paper.

More specifically, the present invention relates to a pressure-sensitive recording paper characterized in that an unsaturated carboxylic acid ester is added to an aromatic oily liquid that is a solvent for a color former. Pressure-sensitive recording paper has recently been widely used in place of carbon copying paper or pigment-type back carbon copying paper, and is also called non-carbon copying paper or carbonless carbon paper due to its functions.

Various forms have been proposed, such as U.S. Pat.
No. 12507, No. 2730456, No. 2730457
No. 341825, No. 3432327, etc. In other words, a nearly colorless organic compound (
Hereinafter referred to as color developer) is dissolved in an organic solvent such as alkylnaphthalene, contained in fine capsules, and coated on a support. A combination of a leaf paper and, in some cases, a medium leaf paper coated with capsules containing a color former on one side of the support and a color developer on the other side, or a combination of the capsules containing the capsules and the heads on the same side of the support. There are those that contain a coloring agent, or those that contain one of the capsules or mauve agent in the support and coated with the other. When using a combination of upper paper and lower paper, upper paper, middle paper, and lower paper, if the capsule layer and developer layer are brought into contact and pressure is applied locally, The capsule in that area is destroyed and the color forming agent and color developer react to produce color. Another form is a single leaf, where the pressurized part develops color, and even a single sheet can be used as recording paper.
It is also possible to copy and record a plurality of sheets by overlapping them. Examples of solvents for dissolving color formers for pressure-sensitive recording paper include hydrogenated terphenyl (Japanese Patent Publication No. 49-2125), alkylnaphthalene (Japanese Patent Publication No. 49-2124), and alkylated diphenylalkanes (Japanese Patent Publication No. 49-2126). ), alkylated triphenyl dimethane (Special Publication No. 49-828y)
, aromatic oily liquids such as alkylated diphenyl (Belgium Patent No. 771661), A-(COOB)n (where A and B are linear or cyclic alkyl groups having 1 to 12 carbon atoms, or allyl groups) ), kerosene, chlorinated diphenyl, chlorinated paraffin, cottonseed oil, linseed oil, soybean oil, and the like are known.

Important properties required for pressure-sensitive recording paper include stability to light of the capsule sheet, coloring ability, and fastness of the coloring body.

However, it is known that ordinary carponic acid esters have a desensitizing effect, so that only extremely low concentrations of coloring agents can be obtained (Japanese Patent Publication No. 491-2124, No. 4
No. 9-2126, Belgian Patent No. 771661).

That is, when esters (aromatic carboxylic acid esters and alkyl carboxylic acid esters) such as those disclosed in JP-A-49-31414 are used as a solvent for a color former, only extremely low color density can be obtained. When such esters are used in combination with other solvents, the decrease in color density may be slightly improved, but the color density cannot be reached for practical use. The purpose of the present invention is to transfer a color former onto a layer of an electron-accepting or proton-donating substance (hereinafter referred to as a color developer) that becomes discolored when it comes into contact with a color former, and to transfer a color former onto a layer of an electron-accepting or proton-donating substance (hereinafter referred to as a color developer). The object of the present invention is to obtain a pressure-sensitive recording paper which has a high color density by promoting development and penetration by an unsaturated carboxylic acid ester and has excellent color fastness.

Another object of the present invention is to obtain an excellent pressure-sensitive recording paper by adding an unsaturated carboxylic acid ester, which exhibits very little loss of coloring ability even when the capsule sheet is irradiated with light.

The present inventors added a small amount of unsaturated carboxylic acid ester, which is different from conventional esters, to an aromatic oil-based liquid, thereby improving the transfer of the color former from the capsule layer to the color developer layer and the transfer of the color former from the capsule layer to the color developer layer. More effectively develops and penetrates the coloring agent,
The present invention was accomplished by discovering that a pressure-sensitive recording paper having a high color former density and excellent color fastness can be obtained. Therefore,
The pressure-sensitive recording paper of the present invention is characterized by containing a small amount of unsaturated carboxylic acid ester in an aromatic oily liquid which is a solvent for dissolving a coloring agent.

The unsaturated carboxylic acid ester referred to in the present invention is a polar liquid that remains within the capsule without being released outside the capsule due to evaporation during the encapsulation process or dissolution in an aqueous solution forming a continuous phase. For example, unsaturated monocarboxylic acid esters and unsaturated dicarboxylic acid esters (in the case of unsaturated dicarboxylic acid esters, the two ester groups do not necessarily have to be the same).

). Among these, unsaturated monocarboxylic acids and unsaturated dicarboxylic acids having 4 to 12 carbon atoms, and alcohols constituting esters having 1 to 6 carbon atoms are particularly effective. Specific examples of unsaturated carboxylic acid esters used in the present invention include propyl crotonate, 3-butenoic acid ethyl ester, Teiglic acid butyl ester, sorbic acid methyl ester, and ethyl methyl maleate. , dibutyl maleate, jetyl maleate, butyl ethyl maleate,
Dimethyl maleate, diethyl citraconate, dimethyl itaconate, dimethyl muconate, and dimethyl dimethylmuconic acid. Among these, especially those without 8 carbon atoms,
The maleic acid esters shown in Table 12 are the most effective.
The amount of unsaturated carboxylic acid ester added to the aromatic oil liquid is 1 to 3% by weight, preferably 2 to 8% by weight.

The ester-based oil-based liquid described in JP-A No. 49-31414 significantly impedes (desensitizes) color development on the color developer layer.
Although not actually used in the industry, aromatic oil-based liquids are widely used in the industry because they have high color former solubility.

In the present invention, the aromatic oil-based liquid used in combination with the unsaturated carboxylic acid ester is an aromatic oil-based liquid that is generally used as a solvent for a coloring agent for pressure-sensitive recording paper.
In particular, when hydrogenated terphenyl, alkylnaphthalene, alkylated diphenylalkane, alkylated triphenyl dimethane, or alkylated diphenyl is used as the aromatic oil, the effect is great. These compounds include;
Examples include those having 1 to 4 alkyl groups having 1 to about 18 carbon atoms. Specifically, hydrogenated triphenyl obtained by hydrogenating triphenyl (terphenyl) at a hydrogenation rate of 15 to 80%, inoctylnaphthalene, indodecylnaphthalene, dimethylnaphthaline, methyldiethylnaphthaline, inpropylnaphthalene, Diisopropylnaphthalene, amylnaphthalene, 2,4-dimethyldiphenylmethane, 2-methyl-5-isopropyldiphenylmethane, 1,1-diphenyl-1-hebutylmethane, dimethyl-t-butyldiphenylmethane,
Examples include 1,5-diphenyl-3-octylbentane and triallyldimethane. As mentioned above, these are as follows:
No. 2126, No. 49-8289, and Belgian Patent No. 771661.

The pressure-sensitive recording paper of the present invention must contain an unsaturated carboxylic acid ester in the oily liquid, but is not particularly limited in other respects.

The method for encapsulating the color former oil of the present invention is as follows:
Known encapsulation methods can be applied.

For example, as a method for manufacturing capsules, US Pat.
457 and 2800458, and an interfacial polymerization method described in British Patent No. 990443 and US Patent No. 3287154.

Methods based on polymer precipitation described in U.S. Pat. No. 341,825 and U.S. Pat. No. 3,660,304;
There is a method of polymerizing a glue actant from inside an oil droplet, as disclosed in US Pat. No. 3,796,666. The solvent of the present invention is particularly effective when used in a method by polymer precipitation and an encapsulation method by polymerizing IJ actant from inside the oil passage. Furthermore, since the solvent of the present invention has the effect of dissolving the raw material of the capsule wall used in these encapsulation methods, it also has the advantage that encapsulation is extremely easy. Typical color formers include triallylmethane compounds, diphenylmethane compounds, xanthene compounds, thiazine compounds, and spiropyran compounds. Specific examples of color formers include:
As triallylmethane compounds, 3,3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (crystal violet lactone, hereinafter referred to as CVL), 3,3-bis(p-dimethylaminophenyl) )
Phthalide, 3-(p-dimethylaminophenyl)-3-
(1,2-dimethylindol-3-yl)phthalide,
3-(p-dimethylaminophenyl)-3-(2-methylindol-3-yl)phthalide, 3-(p-dimethylaminophenyl)-3-(2-phenylindol-3-yl) Phthalide, 3,3-bis(1,2-dimethylindole-3-yl)-5-dimethylaminophthalide, 3,3-bis-(1,2-dimethylindole-3-
yl)-6-dimethylaminophthalide, 3,3-bis-(9-ethylcarbazol-3-yl)-5-dimethylaminophthalide, 3,3-bis-(2-phenylindol-3-yl)- Examples include 5-dimethylaminophthalide, 3-p-dimethylaminophenyl-3-(1-methylpyrrol-2-yl)-6-dimethylaminophthalide, and the like.

Diphenylmethane compounds include 4,4-bis-dimethylaminobenzhydrin benzyl ether, N-halophenyl leukoolamine, and N-2,4,5-tric.

Examples include lofuenyl leukoolamine. Examples of xanthene compounds include rhodamine-B-anilinolactam, rhodamine-(p-nitroanilino)lactam, rhodamine-B(p-chloroanilino)lactam, 3-dimethylamino-6-methoxyfluoran, 3-diethylamino-7-methoxyfluoran, -diethylamino-7-chloro-6-methylfluorane, 3-diethylamino-7
-(acetyllomethylamino/)fluoran, 3-diethylamino-7-(dibenzylamino)fluoran, 3-diethylamino-7-(methylbenzylamino)fluoran, 3-diethylamino-7-(chloroethylmethylamino)fluoran, Examples include 3-diethylamino-7-(diethylamino)fluoran.

Examples of thiazine compounds include benzylleucomethylene blue and p-nitrobenzylleucomethylene blue.

Examples of spiro-based compounds include 3-methyl-spirodinaphthopyran, 3-ethyl-spirodinaphthopyran, and 3-methyl-spirodinaphthopyran.
3'-dichlorospirosinaphthopyran, 3-benzylosespirosinaphthopyran, 3-methylnaphthopyran (
Examples include 3-methoxybenzo)-spiropyran and 3-propyl-spirogipenzodipyran.

Solid acids used as color developers include activated clay materials such as acid clay, activated clay, attapulgite, bentonite, zeolite, etc., or organic acid materials such as phenolic resins, or aromatic acids such as zinc in ditertiary butylsalcylic acids. There are metal salts of carboxylic acids, etc.

The pressure-sensitive recording paper of the present invention has a higher color density than a pressure-sensitive recording paper containing only one of an unsaturated carboxylic acid ester and an aromatic oil-based liquid, but the coloring body obtained has excellent fastness.

These excellent effects are particularly remarkable in pressure-sensitive recording paper, which can be used as a recording paper by itself, in which a color former and a color developer are coated on the same side of a support. EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to the Examples.

In addition, the preparation and application of the acidic Shirashi color developer solution used as a representative example of the color developer in the examples were carried out as follows. water 30
2% caustic soda aqueous solution 8c as a sawdust dispersant
100 g of acidic clay was added to the mixture, and the mixture was dispersed by vigorous lighting.

Styrene-butadiene rubber latex (trade name: SBR Latex No. 636 manufactured by Chemical Corporation) was added as a binder to complete the preparation of a color developer solution containing acid clay. This coating solution was applied to a 50-th grade base paper using an air knife coating so that the solid content was 7 mm/cm, and dried to obtain a lower sheet (hereinafter referred to as a color developer sheet). Example 1 30 days of diisopropylnaphthalene, 1.2 hours of crystal violet lactone, 0.3 hours of benzoyl leucomethylene,
0.2 of 7-diethylamino-3-(dibenzylamino)fluorane, and 0.2 of rhodamine B-(p-nitroaniline)lactam. A polyisocyanate adduct (3 mol of tolylene diisocyanate, 1 mol of -trimethylolpropane adduct) and a polyol (ethylenediamine-propylene oxa) were added as wall film-forming substances to an aromatic oil-based liquid in which a coloring agent was dissolved. dibutyl maleate adduct) were mixed for 1 night, and further dibutyl maleate was added as an unsaturated carboxylic acid ester.
A primary solution was prepared by adding 8 o'clock and 20 o'clock at a temperature below 20 o'clock.

Then 20 ounces of water, 42 liters of turquoise polyvinyl alcohol, and 1.5 ounces of sodium salt of carboxymethylcellulose.
It dissolved the evening. Furthermore, 0.1 g of funnel oil (emulsifier) was added to prepare a secondary solution. The primary solution was poured while vigorously pouring the secondary solution to form an oil-in-water emulsion.

When the oil droplet size reaches 6 to 10 Buddhas, weaken the rope worship,
Then, after adding 100 ml of 20 ml of water into this emulsion, the temperature of the system was gradually increased to 75 ml and kept at this temperature for 60 minutes. Cellulose is added to the capsule liquid thus obtained. After 7.5 days of floc, 95 tons of water was added to complete the preparation of the capsule liquid. This capsule liquid was coated with an air knife to give a solid content of 5.0 to 50 m/m base paper.
The mixture was coated and dried to obtain a paper (hereinafter referred to as capsule sheet).

Comparative Example 1 For comparison with Example 1 (method of the present invention), examples in which the solvent was changed, 'i}, 'ii}, 'Goka and Rib are shown.

The amount of solvent added and the method of use are the same as in Example 1. 'i}
Dibutyl maleate alone (BM) [ii- Diisopropylnaphthalene alone (Kawa) Tsuyoshi Diethyl isopropyl malonate alone (ElM) Combination of diisopropylnaphthalene (30 minutes) and diethylysopropyl malonate (0.8 hours) (ElM Ten I
N) Here, the compound is an example of a saturated fatty acid ester.

A capsule sheet was obtained by processing in exactly the same manner as in Example 1.
Test Results-1 {a- The capsule sheet of Example 1 was layered on the color developer sheet and a load of 600 k9' was applied to develop color.

After the colored mark was left in a dark place for 1 hour, the spectral absorption between wavelengths 700 to 380 was measured using a Toshiba Beckman D matrix spectrophotometer. Table 1 summarizes the measured values for 550 machines and 600 skins.

The above spectrophotometer was also used for the spectral absorption in the tests shown below. The results are shown in a of Table 1.

The colored mark obtained in the above process was further irradiated with sunlight for 1 hour, and then the spectral absorption of the colored mark was measured.

The results are shown in Table 1, b. 'c} After irradiating the capsule surface of the capsule sheet of Example 1 with sunlight for 18 minutes, it was layered on the developer sheet to develop color by applying a load of 600k9/Sakai, and the spectral absorption of the colored mark was measured.

The results are shown in Table 1, c. Said {a}, 'b', 'c
- Exactly the same test as 'i}, 'ii', ' of Comparative Example 1
iii} and rib capsule sheets.

In Table 1, a,
Shown in b and c. The abbreviations of solvents in Table 1 are as follows.

Dibutyl maleate (BM), diisopropylnaphthalene (River), and diethyl isopropyl malonate (E
IN). Table 1 In Table 1, 550 x 1 and 600 x 1 indicate the measured values at their respective wavelengths.

As is clear from the values in Table 1, the density of the colored mark of Example 1 is higher than that of Comparative Example 1, {stop{ii', {iii-}, and any of the others in a, b, and c.

These results show that by adding a small amount of unsaturated carboxylic acid ester to an aromatic oil-based liquid in which a color former is dissolved, the color development of the color mark is improved, and in particular, the silver color caused by light irradiation of the color mark, and the light of the capsule surface. It is clearly seen that a pressure-sensitive recording paper whose coloring ability is less degraded by irradiation can be obtained.

Example 2 The unsaturated carboxylic acid ester in Example 1, dibutyl maleate (0.8%), diethyl maleate (0.8%)
．． A capsule sheet was obtained by processing in exactly the same manner as in Example 1, except that 8 was changed.

Comparative Test Results 2 A comparative test was conducted using the same test method as in Comparative Test Results 1 with a product that did not use unsaturated carboxylic acid ester.

As a result, as in Comparative Test Result 1, by adding a small amount of unsaturated carboxylic acid ester to the aromatic oil-based liquid in which a coloring agent is dissolved, the coloring property of the coloring mark is improved, and in particular, the light irradiation of the coloring mark is improved. A pressure-sensitive recording paper was obtained that exhibited less brown color due to the irradiation of the capsule surface and less loss of coloring ability due to light irradiation of the capsule surface.

Example 3 A capsule sheet was prepared in the same manner as in Example 1 except that 0.8 mm of unsaturated carboxylic acid ester (diptylated maleate) was replaced with 0.8 mm of sorbic acid ethyl ester. Obtained.

Comparative Test Results 3 According to the same test method as Comparative Test Results 1, a comparative test was conducted with a product that does not use unsaturated carboxylic acid ester.

As a result, as in Comparative Test Result 1, by adding a small amount of unsaturated carboxylic acid ester to the aromatic oil-based liquid in which a coloring agent is dissolved, the coloring property of the coloring mark is improved, and in particular, the light irradiation of the coloring mark is improved. A pressure-sensitive recording paper was obtained that exhibited less brown color due to the irradiation of the capsule surface and less loss of coloring ability due to light irradiation of the capsule surface. Example 4 A capsule sheet was obtained in the same manner as in Example 1 except that 0.8 parts of dibutyl maleate was replaced with 1.5 parts of dimethyl maleate.

Claims (1)

[Claims] 1. In pressure-sensitive recording paper using an aromatic oil-based liquid as a color former solvent, it is recommended that the aromatic oil-based liquid contains 1 to 30% by weight of an ester of an unsaturated carboxylic acid having 4 to 12 carbon atoms. Features pressure-sensitive recording paper.