JP2559753B2 - Desensitizing ink - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a desensitizing ink used for pressure-sensitive copying paper and having an excellent desensitizing effect. More specifically, it relates to a desensitizing ink for suppressing or preventing color development of a dye precursor in pressure-sensitive copying paper, which comprises a combination of a colorless or light-colored dye precursor and a color developer that develops the color.

Generally, pressure-sensitive copying paper is a sheet having a microcapsule layer containing a solution of an electron-donating basic dye called a dye precursor (hereinafter referred to as “CB sheet”) and an electron-accepting developer. It is used in combination with a sheet having a coating layer (hereinafter referred to as "CF sheet"). Also,
If a paper coated with a color developer on the front surface and microcapsules containing the dye precursor on the back surface (hereinafter referred to as "CFB sheet") is sandwiched between the CB sheet and the CF sheet, many copies can be made. Is possible.

In the pressure-sensitive copying paper used in this manner, a desensitizing ink is applied to a CF sheet using a printing machine or the like at a portion where copying is not necessary, to suppress or prevent the coloring of the dye precursor.

[Conventional technology]

Known desensitizers include quaternary ammonia salt (Japanese Patent Publication No. 33-3921), tertiary amine having two polyethyleneoxy machines (Japanese Patent Publication No. 46-29546), and initial condensation product of urea resin. (Japanese Patent Publication No. 46-35697), polyethyleneoxy monoalkyl ether (Japanese Patent Publication No. 47-38201), ethylene oxide addition compound of polyalkylene polyamine (Japanese Patent Publication No. 23008), propylene oxide addition compound of alkylene diamine (Japanese Patent Publication No. -23850), polypropylene glycol having an average molecular weight of 400 to 5000 (Japanese Patent Publication No.
5-1919), polyamine glycidyl ester or glycidyl ether addition compounds (Japanese Patent Publication No. 51-22416)
No.), diazabicycloalkenes or salts thereof (Japanese Patent Publication Sho)
54-26926), spiro acetal-based diamine (Japanese Patent Publication Sho 5)
5-16188), active hydrogen polyamines and alkylene oxide addition compounds (Japanese Patent Publication No. 53-23724) and the like are known. These desensitizers are used for letterpress printing, intaglio printing, lithographic printing,
It is prepared and used as a printing ink suitable for a printing method such as stencil printing, that is, a desensitizing ink.

[Problems to be solved by the invention]

In recent years, research on color developers has progressed, and CF and CFB sheets using a polyvalent metal salt of salicylic acid derivative and / or a polyvalent metal salt of salicylic acid co-condensation resin as a color developer have high coloring ability and stability of a colored image. It has been improved and partly put to practical use.

For example, Japanese Examined Patent Publications Nos. 51-25274, 52-1327, and JP-A-5-25327.
4-40898, 61-100493, Japanese Patent Application No. 61-18027, 6
Typical examples are polyvalent metal salts of salicylic acid having various substituents proposed in 2-19673 and the like, and polyvalent metal salts of salicylic acid condensates.

Since CF sheets and CFB sheets that use these salicylic acid-based polyvalent metal salts as color developers have large color-developing ability, when using desensitizing inks that were previously used for phenol resin-type color developers, etc. Has an insufficient desensitizing effect on the dye precursor, and a sufficient effect cannot be obtained unless the volume of ink is increased.

However, when the amount of the ink is increased, the drying speed becomes slow, and there is a problem during printing such as set-off due to insufficient drying or bleeding to a portion where the ink is not printed.

[Means for solving problems]

The present inventors have conducted various studies to solve such problems, and have found that the partial structure (I) -OCHR ¹ CHR ² CH ₂ NH ₂ (I) (R ¹ and R ² are hydrogen atoms or carbon atoms of 1 to 1). The present invention has been completed by finding that the above-mentioned problems can be solved by a desensitizing ink containing a polyetheramine having a lower alkyl group of 5) as a main component.

The polyetheramine compound having the partial structure (I) used in the present invention has the partial structure (II) (Wherein R ¹ and R ^2- represent a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms, and m and n represent integers of 1 to 100). It can be easily obtained by conjugate-adding to an unsaturated nitrile compound and then reducing the cyano group.

Specific examples of the starting material polyether alcohol include HOCH ₂ CH (CH ₂ CH ₃ ) O _n H HOCH ₂ CH (CH ₃ ) O _n H HOCH ₂ CH ₂ O _n HC ₄ H ₉ OCH ₂ CH ₂ O _n H And various molecular weights with k to n of 1 to 100 are readily available.

On the other hand, examples of the α, β-unsaturated nitrile derivative include those represented by the following general formula.

CHR ¹ = CHR ² CN Here, R ¹ and R ² represent an alkyl group having 1 to 5 carbon atoms.

Among these, acrylonitrile, methacrylonitrile, crotyl nitrile and the like are mentioned as specific compounds of the particularly preferable α, β-unsaturated nitrile derivative,
Each of them may be used alone, or one or more of them may be used if necessary, but the invention is not limited to these.

The substance used as a desensitizer in the present invention is generally obtained as a light-colored or pale-yellow oily substance, but has a large affinity with a vehicle resin used for preparation of a desensitized ink, and a moderate hydrophilic property suitable for various printing methods. It has a lipophilic property.

The desensitizing ink of the present invention contains a compound which is a desensitizer component in an amount of 10 to 60% by weight, preferably 30% by weight, in the nonvolatile component of the desensitizing ink.
Contains ~ 50% by weight.

As a component other than the desensitizer for obtaining the desensitizing ink of the present invention (1) As a vehicle resin, a rosin-modified phenol resin, a rosin-modified maleic acid resin, a rosin ester resin,
Ink resins such as maleic acid resin, styrene-maleic acid resin, terpene phenolic resin, polyamide resin, and alkyd resin are generally used, and 10 to 50% by weight, preferably 15 to 30% of the desensitizing ink (in the nonvolatile content). It is contained by weight%.

(2) Titanium dioxide, zinc oxide, barium sulfate, magnesium oxide, talc, silica and calcium carbonate are used as pigments for improving printability, whiteness and hiding power.
˜50% by weight, preferably 15 to 30% by weight.

In addition, glycol solvent, linseed oil,
Drying oils such as tung oil, soybean oil, semi-drying oils such as cottonseed oil, rapeseed oil and rice bran oil, paraffins, metal soaps, UV absorbers, antioxidants, lubricants, optical brighteners, etc. can be used in combination. .

Further, in the production of ink for flexographic or gravure printing, volatile solvents such as lower alcohols, esters, and ketones are added to adjust the viscosity and volatilization rate.

In order to obtain the desensitizing ink of the present invention, various known methods can be used, and if necessary, known desensitizing agents may be used in combination.

[Action and effect]

The desensitizing ink containing the polyetheramine derivative of the present invention as an active ingredient is not limited to letterpress and dry offset printing,
It is possible to provide ink properties that can be printed by various printing machines such as flexography, gravure, and offset printing.

It is considered that the desensitizing action of the desensitizing ink of the present invention is to inactivate the developer by neutralizing the coloring site (acid site) of the acidic developer with the amine component of the desensitizer.

The desensitizing ink of the present invention has an excellent desensitizing effect on clay-based (eg, acid clay, activated clay, attapulgite), phenol formaldehyde resin-based color developer, etc., but is especially a polyvalent metal salt of salicylic acid derivative. In addition, with respect to the polyvalent metal salt of salicylic acid co-condensed resin and the like, the desensitized printed part has very little change (coloring) with time in combination with the excellent desensitizing effect.

The desensitizing ink of the present invention is various fluorane-based, triallylmethanephthalide-based, pyridylphthalide-based, acylleucophenothiazine-based, rhodamine-anilinolactam-based that are widely used as pressure-sensitive dyes (dye precursors). When applied to the surface of a color developer, the compound exerts an excellent desensitizing effect (color development preventing effect).

The desensitizing agent used for the desensitizing ink of the present invention has excellent printability not only in desensitizing printing by gravure, flexo, and letterpress printing methods, but also in wet offset printing, and a sufficient desensitizing effect with a small amount of volume. Since it has it, it can correspond to the high-speed printing.

The CF sheet and CFB sheet coated with the desensitizing ink of the present invention do not yellow with time and have no odor, and a good printed surface can be obtained.

Desensitizing ink of the present invention is a color developer coating surface weight servings to (CF surface) 0.5 g / cm ² or more, preferably to exhibit sufficient desensitizing effect by printing 1 to 5 g / cm ² .

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

CB and CF sheets used in Examples and Comparative Examples were prepared as follows.

Preparation of CB sheet 100 parts of a 10% aqueous solution of ethylene maleic anhydride and water 2
Mix 40 parts and adjust the pH to 4.0 with 10% aqueous sodium hydroxide.
And in this, 3-diethylamino-6-methyl-7-
After 200 parts of alkylnaphthalene in which 5% by weight of anilinofluorane was dissolved was emulsified with a homomixer, 60 parts of a methylated methylolmelamine aqueous solution (Mitsui Toatsu Kagaku "Euramine T-530") having a solid content of 50% was added and stirred. The temperature was kept at 55 ° C for 3 hours to obtain a microcapsule liquid having an average particle size of 5.0μ.

To 100 parts of this microcapsule liquid, 20 parts of flour starch granules and 2 parts
20 parts of 0% oxidized starch powder and 116 parts of water were added, and the mixture was stirred and coated on 40 g / m ² paper so as to have a solid content of 5 g / m ² to obtain a CB sheet.

Preparation of CF sheet (A) 3,5-dibenzylsalicylic acid zinc salt was wet-milled using a sand grinding mill in the presence of a small amount of a polymeric anionic surfactant to give a solid content of 40% by weight. An aqueous suspension of was prepared.

Using the aqueous suspension, an aqueous paint having the following composition (solid content
30%), and the dry coating amount of 40 g / m ² of high-quality paper is 5.5 g / m
A CF sheet (A) was prepared by coating and drying so as to be ² .

Composition of water-based paint Solid weight part Light calcium carbonate 100 Developer 20 Adhesive Oxidized starch 8 Synthetic latex 8 Preparation of CF sheet (B) 3,5-Dibenzyl salicylic acid-α, α'dimethoxy instead of zinc salt A CF sheet (B) was prepared in the same manner using a zinc salt of a -p-xylene-mesitylene co-condensation resin.

Synthesis Example 1 Synthesis of Polyetheramine 360 g of polypropylene glycol (average molecular weight 1200) was dissolved in 720 ml of tetrahydrofuran, and 12 g of potassium t-butoxide was added.

Add 35.0 g of acrylonitrile to this solution and add 12 at 50 ° C.
Stir for hours. After completion, the reaction was poured into 1000 ml semi-saturated saline and the organic layer was separated. Volatile components contained in the organic layer were removed under reduced pressure to obtain 390 g of an oily substance.

This oily substance was dissolved in 1000 ml of dry ether, and 23 g of lithium aluminum hydride was added little by little.
Stir for hours. To this solution, 50 ml of ethyl acetate was added little by little to inactivate the excess reducing agent, and then 25 ml of water was added. The reaction solution was dried over anhydrous sodium sulfate, filtered, and the solvent was distilled off under reduced pressure to obtain 384 g of polypropyleneoxydiamine (compound (A)).

Average molecular weight 1300 Synthesis Examples 2 to 5 In the same manner as in Synthesis Example 1, compounds (B) to (E) were obtained.

Example 1 40 parts of titanium oxide was added to a varnish obtained by heating and dissolving 40 parts of the desensitizer obtained in Synthesis Example 1 and 30 parts of a rosin-modified maleic acid resin as a binder, and the mixture was kneaded with a three-roll to form a desensitizing ink. Obtained. This was printed on CF sheets (A) and (B) by a relief printing machine at 3.5 g / m ² .

Each of the obtained desensitized printing paper and CB paper was combined and passed through a super calendar roll with a linear pressure of 100 kg / cm for color development operation, and the color density value (Macbeth density Vis value) was measured after standing for one day. The desensitizing effect was evaluated.

Examples 2 to 5 The desensitizing effect was evaluated in the same manner as in Example 1 except that the desensitizing agents obtained in Synthesis Examples 2 to 5 were used.

Comparative Examples 1 to 3 The desensitizing effect was evaluated in the same manner as in Example 1 except that the desensitizing agent was not used and polypropylene glycol was used as the desensitizing agent. The results obtained are shown in Table 1.

The numerical values in Table 1 indicate the desensitizing effect. The smaller the numerical value, the greater the effect, and the values of 0.05 to 0.06 in Examples 1 to 5 mean that the desensitizing effect is completely desensitized.

The desensitizing ink using the polypropylene glycol of Comparative Example 2 does not have sufficient desensitizing effect on the salicylic acid polyvalent metal salt and / or the salicylic acid co-condensation resin polyvalent metal salt-based developer.

In the examples, an example of a letterpress ink and a desensitizing printing paper using the ink was shown, but the present application is not limited to letterpress ink, and includes offset printing ink, flexographic printing ink, and gravure printing ink. is there.

Claims (1)

(57) [Claims] 1. A polyetheramine having a partial structure (I) —OCHR ¹ CHR ² CH ₂ NH ₂ (I) (R ¹ and R ² represent a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms). A desensitizing ink, which comprises: