JPS63144082A - Microcapsule sheet for pressure-sensitive recording - Google Patents

Abstract

PURPOSE:To improve fogging at the time of printing and bleeding due to a ribbon in numbering printing, namely, solvent resistance, by incorporating a specified modified polyvinyl alcohol containing a hydrophobic group in the molecule thereof into a color former-containing microcapsule layer. CONSTITUTION:A modified polyvinyl alcohol containing a hydrophobic group in the molecule thereof has a hydrophobic group R-X (wherein R is a 4C or higher alkyl, and X is O or S) in the molecule thereof, and is used in an amount of 0.1-2.0g/m<2>, preferably, 0.3-1.0g/m<2>. A color former used in a microcapsule sheet is not particularly limited, and may be a triarylmethane compound, a diphenylmethane compound, a xanthene compound or a mixture thereof. Color former-containing microcapsules may be produced by an interfacial polymerization method, an internal polymerization method, a phase separation method, an external polymerization method, a coacervation method or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a microcapsule sheet for pressure-sensitive recording, and more particularly, it relates to a pressure-sensitive recording microcapsule sheet that has excellent color development, less capri during printing, and excellent solvent resistance. The present invention relates to a microcapsule sheet for use.

(Prior art) A pressure-sensitive recording sheet supports a microcapsule layer containing microcapsules in which a colorless electron-donating dye (hereinafter referred to as a coloring agent) is dissolved in an appropriate solvent and the resulting oil droplets are microencapsulated. A top paper coated on a support, a bottom paper coated with a developer layer containing an electron-accepting compound (hereinafter referred to as a developer) on another support, and in some cases one side of the support. A combination of a medium paper coated with a microcapsule layer on one side and a color developer layer on the other side, or a support containing the capsules and a color developer on the same side, or There are capsules that contain one of the capsules or the color developer and the other coated with the other.

These pressure-sensitive recording papers are described, for example, in U.S. Patent No. 2,505.4.
No. 70, No. 2,505,489, No. 2゜550.47
No. 1, No. 2,730,457, No. 3,418,250
It is stated in the number etc.

However, these microcapsule sheets for pressure-sensitive recording suffer from fogging during printing and bleeding due to ink on the numbering ribbon, and have shortcomings in solvent resistance.

(Objective of the Invention) An object of the present invention is to provide a microcapsule sheet for pressure-sensitive recording which has improved fogging during printing and bleeding due to the ribbon during pick-up printing, that is, improved solvent resistance.

(Structure of the Invention) The object of the present invention is to provide a pressure-sensitive material, characterized in that a color former-containing microcapsule layer contains modified polyvinyl alcohol containing a hydrophobic group made of a hydrocarbon having 4 or more carbon atoms in the molecule. This was achieved using a recording microcapsule sheet.

The modified polyvinyl alcohol containing a hydrophobic group in the molecule used in the present invention has a hydrophobic group R-X- in the molecule (R is an alkyl group having 4 or more carbon atoms, and X is O
or S).

The modified polyvinyl alcohol used in the present invention can be synthesized by, for example, saponifying polyvinyl ester polymerized in the presence of a chain transfer agent having a hydrophobic group having 4 or more carbon atoms.

Chain transfer agents having 4 or more carbon atoms used in the present invention include long-chain alkyl mercaptans and long-chain alkyl alcohols, and alkyl mercaptans are most suitable. Specific examples include octyl mercaptan, lauryl mercaptan, stearyl mercaptan, hexanol, octatool, myristyl alcohol, and stearyl alcohol. These may be used alone or in combination of two or more. The degree of polymerization and saponification of the modified polyvinyl alcohol of the present invention are not particularly limited, but the degree of polymerization is usually 80 to 80. 2400, preferably 200 to 1000. Also, the degree of saponification is 60%
99.8%, preferably 80% to 98.5%. The hydrocarbon, which is a hydrophobic group, has 4 or more carbon atoms, preferably 6 to 20 carbon atoms.The polyvinyl alcohol of the present invention may contain a modifying group selected from an anionic group, a cationic group, and a nonionic group. can be included.

The amount of modified polyvinyl alcohol used in the present invention is preferably 0.1 to 2.0 g/n (more preferably 0.3 g/n).
~1.0g/rd.

In addition, natural and synthetic polymer compounds conventionally generally used as binders, such as polyvinyl alcohol, methyl cellulose, starch, carboxymethyl cellulose, styrene-maleic acid copolymer, polyamide resin, polyacrylamide resin, styrene-butadiene copolymer, etc. may be used together.

The color former used in the microcapsule sheet of the present invention is not particularly limited, but specific examples of these color formers include triarylmethane compounds, diphenylmethane compounds, xanthine compounds, thiazine compounds, and spiro compounds. , a fluoran compound, or a mixture thereof.

These color formers are dissolved in a solvent, encapsulated, and applied to a support. As the solvent, natural or synthetic oils can be used alone or in combination.

Examples of solvents include cottonseed oil, kerosene, paraffin, naphthenic oil, alkylated biphenyls, alkylated terphels, chlorinated paraffins, alkylated naphthalenes, diphenylalkanes, etc. 0 As a method for producing color former-containing microcapsules The interfacial polymerization method, internal polymerization method, phase separation method, external polymerization method, coacervation method, etc. are used.

In preparing a coating solution containing color former-containing microcapsules, a capsule protectant such as cellulose powder, starch particles, talc, etc. is added in addition to the above-mentioned binder to obtain a color former-containing microcapsule coating solution.

The performance of the microcapsule sheet for pressure-sensitive recording of the present invention was tested using the following color developer sheet.

(Adjustment of color developer sheet) 70 parts of water, 2 parts of zinc oxide, 18 parts of calcium carbonate, and 3 parts of calcium carbonate.
, 4 parts of zinc 5-di-α-methylbenzylsalicylate were added and mixed, and then dispersed for 30 minutes using an attritor, to which 2.5 parts of carboxy-modified SBR latex was added in terms of solid content.
part and 10% by weight pVA (degree of oxidation: 99% degree of polymerization: 10%
00) Water soluble! 12 parts of a were added and stirred uniformly to obtain a coating solution. 50g/n of this coating liquid? 4 g on base paper
A developer sheet was obtained by coating and drying using an air knife coater capable of coating a solid content of /rd.

(Example of the invention) The present invention will be specifically explained below using Examples.

The invention is not limited to the examples.

(Example 1) 5 parts of a partial sodium salt of polyvinylbenzenesulfonic acid was added to 95 parts of hot water at about 80'C with stirring and dissolved therein. After dissolving for about 30 minutes, it was cooled. p of aqueous solution
H was 2 to 3, and a 20% by weight aqueous sodium hydroxide solution was added thereto to adjust the pH to 4.0.

while 2.5% crystal violet lactone and 1
．． 100 parts of diisopropylnaphthalene in which 0% henzoleicomethylene blue was dissolved was emulsified and dispersed in 100 parts of a 5% aqueous solution of the partial sodium salt of polyvinylbenzenesulfonic acid to obtain an emulsion having a particle size of 5 μm on average. Separately, 6 parts of melamine, 11 parts of a 37% by weight formaldehyde aqueous solution, and 30 parts of water were heated and stirred at 60°C.
After 0 minutes, a transparent mixed aqueous solution of melamine, formaldehyde and melamine-formaldehyde initial condensate was obtained. The pH of this mixed aqueous solution was 6.0 to 8.0. Below is the first melamine and formaldehyde and melamine-formaldehyde! The mixed aqueous solution of the 1J11ii compound is referred to as an initial condensate solution. 3. Add and mix the initial condensate solution obtained by the above method to the above emulsified mixture and stir.
The pH was adjusted to 6.0 with a 6% by weight hydrochloric acid solution, the temperature of the solution was raised to 65° C., and the mixture was incubated for 360 minutes to obtain a microcapsule solution. This capsule liquid was cooled to room temperature and 20% by weight
The pH was adjusted to 9.0 with sodium hydroxide.

A 10% hydrophobic group-modified polyvinyl alcohol aqueous solution (carbon number 12, polymerization method 300, saponification degree 98%; hereinafter referred to as modified polyvinyl alcohol) was added to the obtained capsule liquid.
and carboxy-modified SBR latex (SN-307i
(manufactured by Sumitomo Naugatux) (as solid content), 30 parts of starch particles, and calcium carbonate (Univer 70;
(manufactured by Shiraishi Calcium) was added thereto, and water was added to adjust the solid content concentration to 20% to prepare a color former-containing microcapsule coating solution.

This coating liquid was applied to a 50 g/rd base paper using an air knife coater so that a solid content of 5 g/n was applied.
After drying, a microcapsule sheet for pressure-sensitive copying was obtained.

(Examples 2 to 7 and Comparative Examples 1 to 5) Pressure-sensitive samples were prepared in the same manner as in Example 1, except that the polymer compounds shown in Table 1 were used instead of the modified polyvinyl alcohol in Example 1. A recording microcapsule sheet was obtained.

Table 1 The microcapsule sheet for pressure-sensitive recording of the present invention was evaluated in the following manner.

(Printing fog) Printing was performed on the back side of the microcapsule sheet using a letterpress printing machine. The printed material is overlapped with a color developer sheet, and 35
A load of 30 g/- was applied at 80% RH and left for 5 days. The capri on the developer sheet that overlapped with the printed portion of the capsule sheet was observed and evaluated as follows.

○: Capri does not occur.

Δ: Capri occurs, but at a level that poses no problem for practical use.

x: Fogging is severe and is a practical problem.

(Suitability for numbering) A capsule sheet and a color developer sheet were stacked, and a numbering machine was used to number the capsule sheet. The colored material on the obtained color developer sheet was observed and evaluated as follows.

O: No bleeding caused by the oil of the numbering ribbon occurred on the colored body.

Δ: There is some smearing, but the numbers on the numbering can be read.

×: The numbers are difficult to read due to severe bleeding.

(Solvent Resistance) The capsule sheet was immersed in the solvent shown in Table 2 for 1 minute. After immersion, it was layered with a color developer sheet to develop color, and the decrease in color development was evaluated as follows.

○: No deterioration in color development.

Δ: There is a decrease in color development, but there is no practical problem.

×: No color development observed.

Table 2 Patent Applicant: Fuji Photo Film Co., Ltd. Procedural Amendment (Voluntary) January 1986, Office Director-General's Palace)
1.Display of the incident Showa A/year long-awaited Kota 2020
No. 2, Title of the invention Microcapsule sheet for pressure-sensitive recording 3, Relationship with the case of the person making the amendment Patent applicant contact information 10
6 2-26-30, Nishi-Azabu, Minato-ku, Tokyo 4, Subject of amendment: Section of “Claims” and “Detailed Description of the Invention” of the specification & Contents of amendment (I) No. 10 of the specification Replace Table 1 on page 1 with the following.

“　　　Table 7 ” (2. Amend the claims as shown in the attached sheet.

Attachment "Claims: A microcapsule sheet for pressure-sensitive recording, characterized in that a microcapsule layer containing a coloring agent contains a modified polyvinyl alcohol containing a hydrophobic group represented by general formula (I) in its molecule.

R-X(I) (R: alkyl group having more than one carbon number X: 0
or S)”

Claims (1)

[Scope of Claims] A microcapsule sheet for pressure-sensitive recording, characterized in that a microcapsule layer containing a coloring agent contains a modified polyvinyl alcohol containing a hydrophobic group represented by the general formula (I) in its molecule. R-X (I) (R: alkyl group having 4 or more carbon atoms X: O
or S)