JP2601469B2 - Desensitizing ink - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a desensitizing ink excellent in desensitizing effect used for pressure-sensitive copying paper. More specifically, the present invention relates to a desensitizing ink for suppressing or preventing the coloring of a dye precursor in a pressure-sensitive copying paper comprising a combination of a colorless or light-colored dye precursor and a color developing agent.

In general, a pressure-sensitive copying paper has a sheet having a microcapsule layer containing a solution of an electron-donating basic dye called a dye precursor (hereinafter referred to as a “CB sheet”) and an electrophilic developer applied. It is used in combination with a sheet having a layer (hereinafter, referred to as “CF sheet”). Also, paper coated with microcapsules containing a color developer on the front surface and a dye precursor on the back surface (hereinafter referred to as “CFB sheet”)
If you use it between B sheet and CF sheet, you can copy many sheets.

In the pressure-sensitive copying paper used in this way, a desensitizing ink is applied to a CF sheet using a printing machine or the like on portions where copying is not necessary, thereby suppressing or preventing the coloring of the dye precursor.

[Conventional technology]

Known desensitizers include quaternary ammonium salts (JP-B-33-3921), tertiary amines having two polyethylene oxide groups (JP-B-46-29546), and precondensates of urea resins. (JP-B-46-35697), polyoxyethylene monoalkyl esters (JP-B-47-38201)
No.), ethylene oxide adducts of polyalkylene polyamines (JP-B-49-23008), propylene oxide adducts of alkylenediamines (JP-B-49-23)
No. 850), polypropylene glycol having an average molecular weight of 400 to 5000 (Japanese Patent Publication No. 55-1919), and a glycidyl ester or glycidyl ether adduct of a polyamine (Japanese Patent Publication No. 51-1978).
No. 22416), diazabicycloalkenes or salts thereof (JP-B-54-26926), spiroacetal diamines (JP-B-55-16188), active hydrogen polyamine and alkylene oxide adduct (JP-B-53-23724) Others are known.

These desensitizing agents are prepared and used in printing inks corresponding to printing methods such as letterpress printing, intaglio printing, lithographic printing, and stencil printing, that is, desensitizing inks.

[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 a salicylic acid derivative and / or a polyvalent metal salt of a salicylic acid co-condensation resin as a color developer. Are improved in color-forming ability and stability of a color-developed image, and are partially put into practical use.

For example, JP-B-51-25174, JP-B-52-1327, JP-A-5
4-40898, JP-A-61-100493, Japanese Patent Application No. 61-18027
And polyvalent metal salts of salicylic acid having various substituents and polyvalent metal salts of salicylic acid-based condensates proposed in Japanese Patent Application No. 62-19673.

CF sheets and CFB sheets using these salicylic acid-based polyvalent metal salts as a color developer have a large color-developing ability. Therefore, when a desensitizing ink used in a phenol resin-based color developer or the like is used, The desensitizing effect on the dye precursor is insufficient, and a sufficient effect cannot be obtained unless the amount 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.

Some of the adducts of alkylamines and ethylene oxide or propylene oxide, which have been proposed in some cases, have excellent desensitizing effects, but generally have high affinity for water, which poses a problem especially for offset printing inks. Had left.

[Means to solve the problem]

The present inventors have conducted various studies to solve such a problem, and found that the general formula (I) (Wherein, R _{1 to} R ₄ are each a hydrogen atom, or R ₅ is a hydrogen atom or a lower alkyl group,
R ₇ is a hydrogen atom or a lower alkyl group. N is an average of 1 to 100. The inventors have found that the above problems can be solved by using a polyetheramine derivative represented by the formula (1) as a main component, and have completed the present invention.

The desensitizer used in the present invention has a basic skeleton represented by the general formula (I), and generally has a general formula (II) (Wherein R is a hydrogen atom or an alkylene group, and n is an average of 1 to 100), a diamine derivative obtained by reacting a polyalkylene glycol with ammonia.
Alternatively, it is a liquid composition obtained by an addition reaction between the derivative and an alkylene oxide or a hydroxyalkyl (meth) acrylate.

Examples of specific compounds include H ₂ N—CH ₂ CH ₂ (OCH ₂ CH ₂ ) _n NH ₂ Alternatively, addition reaction products of these with hydroxyethyl acrylate, hydroxyethyl methacrylate, and the like are exemplified as preferable ones, but are not limited thereto.

The compound represented by the general formula (I) or a mixture thereof used as a desensitizer in the present invention is
In general, it is obtained as a light-colored or light-yellow liquid, has a low affinity for water, and has a high affinity for a vehicle resin used for preparing a desensitized ink.

The desensitizing ink of the present invention contains a polyetheramine derivative as a desensitizing component in an amount of 10 to 60% by weight, preferably 15 to 50% by weight in a nonvolatile component of the desensitizing ink.

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

(Ii) White inorganic pigments such as titanium dioxide, zinc oxide, calcium carbonate, clay and the like are contained as pigments in an amount of 10 to 50% by weight, preferably 15 to 40% by weight.

In addition, additives such as vegetable oils such as linseed oil, tung oil, soybean oil, and cottonseed oil, animal oils, paraffin, metal soap, etc., as necessary, ultraviolet absorbers, antioxidants, lubricants, fluorescent brighteners, etc. Can be used in combination.

Further, for preparing an ink for flexographic or gravure printing, a volatile solvent such as a lower alcohol, an ester or a ketone is added to adjust the viscosity and the rate of volatilization.

In order to obtain the desensitizing ink of the present invention, various known methods can be used, and if necessary, a known desensitizing agent 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 printing, but includes flexo, gravure,
It is possible to provide ink properties that can be printed by various printing presses such as offset printing, and it can also cope with a wet offset printing method generally used for high-speed printing of desensitizing ink.

The desensitizing effect of the desensitizing ink of the present invention is considered to be due to the fact that the amine component of the desensitizing agent neutralizes the coloring site (acid site) of the acidic developing agent, thereby inactivating the developing agent.

The desensitizing ink of the present invention includes clays (for example, acid clay,
Activated clay, attapulgite) It has an excellent desensitizing effect on color developers, phenol formaldehyde polymer type developers, etc., especially polyvalent metal salts of salicylic acid derivatives or polyvalent metal salts of salicylic acid co-condensation resin. In combination with the excellent desensitizing effect, the temporal change (coloring) of the desensitized printed portion is extremely small.

Examples of the dye precursor which is effective when applied and printed on the developer surface include various fluoran-based, triallylmethanephthalide-based, pyridylphthalide-based, acylleukophenothiazine-based, and rhodamine anilinolacram-based. It has an excellent desensitizing effect (coloring preventing effect) on these dye precursors and the like.

The desensitizer used in the desensitizing ink of the present invention generally has a very low solubility in water, so gravure, flexo,
It has excellent printing suitability in wet offset printing as well as desensitized printing by the letterpress printing method, and has a sufficient desensitizing effect with a small amount of printing, so that it can respond to high-speed printing.

The CF sheet and CFB sheet coated with the desensitizing ink of the present invention can obtain a good printed surface without yellowing over time and odor.

Desensitizing ink of the present invention is a color developer coating surface weight servings to (CF surface) 1 g / cm ² or more, preferably to exhibit sufficient desensitizing effect by printing 2 to 10 g / cm ^2.

〔Example〕

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

CB sheets and CF sheets used in the 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
40 parts were mixed, the pH was adjusted to 4.0 with a 10% aqueous NaOH solution, and 200 parts of alkylnaphthalene in which 5% by weight of 3-diethylamino-6-methyl-7-anilinefluoran was dissolved was emulsified with a homomixer. Methylated methylol melamine aqueous solution with 50% solid content (Mitsui Toatsu Chemical "Euramine T-
530 "), and kept at 55 ° C. for 3 hours with stirring to obtain a microcapsule solution having an average particle size of 5.0 μm.

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

Preparation of CF Sheet (A) The zinc salt of 3,5-di-α-methylbenzylsalicylic acid was wet-milled using a sand grinding mill in the presence of a small amount of a high molecular weight anionic surfactant, and solidified. An aqueous suspension with a mold weight of 40% by weight was prepared.

Using the aqueous suspension, an aqueous paint having the following composition (solid
Create 30%), dry coating amount of fine paper 40 g / m ² is 5.5 g / m
Coating and drying were performed to obtain CF-sheet (A) so as to be ² .

Composition of aqueous paint Solid parts by weight Soft calcium carbonate 100 Developer 20 Adhesive Oxidized starch 8 Synthetic latex 8 Preparation of CF sheet (B) Instead of 3,5-di-α-methylbenzylsalicylic acid, salicylic acid-α, α 'Dimethoxy-p-xylene-
A CF sheet (B) was similarly prepared using a zinc salt of a mesitylene co-condensation resin.

Example-1 Was added to 50 parts of polyoxypropylenediamine [Jeffamine D-230 manufactured by Mitsui Texaco Co., Ltd.], and dissolved by heating to prepare a varnish. Titanium dioxide (40 parts) was added to the varnish, and the mixture was uniformly kneaded with a three-roll mill to obtain a desensitizing ink.

The amount of the obtained desensitizing ink applied to the CF sheet (A) and CF sheet (B) of the pressure-sensitive copying paper using a letterpress printing machine is 3 g / m 2.
Printed to be ² . The resulting desensitized printing paper and the CB sheet were combined and printed with an electric typewriter (IBM-65 type). The desensitized printing part was CF sheets (A) and (B).
In both cases, no color was formed and a sufficient desensitizing effect was observed.

Example-2 A maleic acid resin 20 was added to 50 parts of a polyoxypropylenediamine [Jeffamine D-2000 manufactured by Mitsui Texaco]
Varnish was prepared by heating and dissolving to prepare a varnish. Next, 20 parts of titanium oxide and 10 parts of calcium carbonate were added, and the mixture was stirred with a mixer and kneaded with a three-roll mill to obtain a desensitized ink. The obtained desensitizing ink is converted to CF using a wet offset printing machine.
3.5 g / m ² coating amount on sheet (A) and CF sheet (B)
As a result, the image portion and the non-image portion were clearly separated from each other, and the print finish was good.

A typewriter (IBM-65) was used in the same manner as in Example-1.
), No color was formed in the desensitized print area, and a sufficient desensitizing effect was recognized.

Example-3 Using a reaction product of polyoxypropylene diamine and hydroxyethyl acrylate [Jeffamine SHA-202 manufactured by Mitsui Texaco] shown as a desensitizer,
A desensitizing ink was prepared in the same manner as in Example 1. The desensitized printing part printed by the letterpress printing method confirmed a sufficient desensitizing effect in combination with the CB sheet.

Comparative Example Polypropylene glycol (molecular weight 300
A desensitizing ink was prepared in the same manner as in Example 1 except that 0) was used, and letterpress printing (application amount: 3 g / m ² ) was performed on the CF sheet (A) and the CF sheet (B).

When a typewriter was colored in combination with the CB sheet in the same manner as in Example 1, a pale black colored image was produced even in the desensitized printing section, and a sufficient desensitizing effect was not obtained.

Claims (2)

(57) [Claims] 1. The compound of the general formula (I) (Wherein, R _{1 to} R ₄ are each a hydrogen atom, or R ₅ is a hydrogen atom or a lower alkyl group,
R ₇ is a hydrogen atom or a lower alkyl group. N is an average of 1 to 100. A desensitizing ink for pressure-sensitive copying paper, characterized by using a polyetheramine derivative represented by the formula (1). 2. The method according to claim 1, which has a desensitizing effect on a color developing layer using a polyvalent metal salt of a salicylic acid derivative and / or a polyvalent metal compound of a salicylic acid co-condensation resin as a color developing agent. Desensitizing ink.