JPS6050599B2 - Photocurable desensitizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a pressure-sensitive copying paper or a thermal recording paper in which an electron-donating colorless organic compound and an electron-accepting compound or a solid acid are combined. It relates to a desensitizer that no longer develops color even when it comes into contact with a compound or solid acid.

More specifically, the present invention relates to a polyalkylene oxide desensitizer having one or more photopolymerizable, in other words photocurable, ethylenically unsaturated bonds at the end of the molecular chain.

The aim is to provide a fast-drying desensitizer.

Usually, pressure-sensitive copying paper is made by dissolving electronic leuco dyes such as crystal violet lactone, benzoyl leucomethylene blue, malachite green lactone, and rhodamine anilinolactam in non-volatile oil and incorporating them into microscopic capsules. The upper paper is coated with an electron-accepting substance or solid acid such as activated clay, acid clay, attapulgide, various phenol resins, and polyvalent metal salts of salicylic acid derivatives together with a suitable binder. When the coated sides of both papers are stacked facing each other and pressure is applied by writing or using a typewriter,
The capsule in the pressurized part is destroyed and the leuco dye and solid acid come into contact and develop color.

Furthermore, if a middle sheet coated with a solid acid on the surface and a capsule containing leuco dye on the back is used by sandwiching it between the top sheet and the bottom sheet, an even larger number of copies can be obtained. Thermosensitive recording paper usually contains fine powder of lactone-type leuco dyes (electron donors) such as crystal violet lactone, malachite green lactone, and 3-diethylamino-6-methyl-7-anilinofluorane, and bisphenol A1 salicylic acid. A fine powder of a solid organic acid, typified by
At least one of the fine powders melts in the heated portion, and the leuco dye and acid come into contact and develop a color. Therefore, pressure-sensitive copying paper and heat-sensitive recording paper have the same chemical reaction mechanism in color reaction. Desensitizers are used to prevent color development by pre-coating areas on the electron-receptive surface of pressure-sensitive copying paper that do not need color development, or to partially cover areas that have already developed color to erase the developed color image. . In the case of heat-sensitive recording paper, if a desensitizer is similarly applied to the heat-sensitive layer, color development can be inhibited and the developed color image can be erased. Conventionally known desensitizers include, for example,
Cationic quaternary ammonium salts (e.g., dodecyltrimethylammonium chloride), aliphatic amine acetates (e.g., n-dodecylamine acetate), higher aliphatic amines (e.g., dodecyl diamine), as described in Publication No. 3-3921, Oxazoline derivatives (e.g., 2,4,4-trimethyl-2-oxazoline), tertiary amines having two polyethylene oxide groups described in Japanese Patent Publication No. 46-29546 (e.g., N,N-dipolyoxyethyleneethylamine) ), polyoxyethylene monoalkyl ester (general formula RCOO
(02H40). ．． H. ．． R is an alkyl group having 12 to 18 carbon atoms (e.g., polyoxyethylene oleyl ester),
Propylene oxide addition compounds of alkylene diamines (e.g. polyoxypropylene diethylamine) described in Japanese Patent Publication No. 49-2385, poly γ-alkyl glutamates described in Japanese Patent Publication No. 49-4484, Japanese Patent Publication No. 49-230
Polyamine-ethylene oxide adduct compound of No. 08, amine-glycidyl ester of JP-A-49-72009 (
or ether) addition compounds, polypropylene glycol of JP-A-50-37507, alkyl or arylamine-propylene oxide-ethylene oxide co-addition compounds of JP-A-50-83318, and others, but most of them include polyethylene oxide and It has a polyether chain in the molecule, such as polypropylene oxide, and has an alcoholic hydroxyl group at the end.
It is an organic compound with a molecular weight (usually several hundred molecular weight or more).

Now, in order to prevent color development by applying a desensitizer to the sides of the middle and bottom sheets of pressure-sensitive copying paper coated with an acidic substance (color developer),
It is common for formulations containing desensitizing agents (desensitizing inks) to be applied in a pattern by printing methods.

In particular, desensitizing inks made of desensitizers, pigments, vehicles, etc. are often printed using letterpress printing machines. However, since these desensitized inks are penetrating drying type inks, they have the disadvantage of slow ink setting and difficulty in increasing printing speed.Furthermore, in recent years, significant advances in dyes and acidic substances (color developers) have made it difficult to develop color. Due to the improved ability, when printing with desensitizing ink, the desensitizing effect is less likely to be exhibited than before, and there is a tendency that the sufficient effect will not be achieved unless the amount of ink applied (the amount of adhesion per unit area) is increased. Increasing the amount of ink applied slows down the drying speed, which tends to cause more problems in the printing process.

Traditionally, activated clay was mainly used as a color developer, but
This had a large surface area and excellent ink absorption.

However, the phenolic resins and salicylic acid derivatives that have come to be used as synthetic color developers in recent years have the disadvantage that the drying rate of desensitized inks is slow because they do not themselves have ink absorption ability. On the other hand, printing machines have made remarkable progress, and efforts are being made to increase efficiency by increasing speed, and the amount of carbonless pressure-sensitive copying paper used is increasing year by year.

Against this background, there is a strong demand for increased printing speed and efficiency of desensitized inks, and in particular, the development of quick-drying desensitized inks and the early achievement of quick-drying desensitized ink printing systems are eagerly awaited.

As a way to meet such demands, it is conceivable to apply photocuring drying systems using ultraviolet curable printing inks, which have already been implemented in the fields of monochrome printing and multicolor printing, to the technical field of desensitized ink printing. British patent for ultraviolet curable printing ink. As is known from Wani Publication No. 119825, a photosensitive vehicle (usually other resins) consisting basically of a photopolymerizable unsaturated monomer and a photopolymerization initiator (photosensitizer) , chain transfer agent,
Ink is made by mixing coloring pigments or dyes with polymerization inhibitors, solvents, etc. for practical use.

Therefore, in the desensitizing ink, by mixing a compound with an excellent desensitizing effect (ie, a desensitizer) into the "4-photosensitive vehicle", an ultraviolet curable desensitizing ink can be obtained.

As the desensitizing agent to be mixed at this time, many of the known and commonly used polymerization-inactive (that is, not having unsaturated groups) compounds as mentioned above can be considered. However, desensitizing inks usually contain a desensitizing agent that accounts for 3% or more of the desensitizing ink, and desensitizing agents are usually liquids, so in the case of ultraviolet-curable desensitizing inks, the term "photosensitive" is used. Since the reactive vehicle is diluted with a large amount of photopolymerizable inactive desensitizer, this is disadvantageous from the standpoint of photocuring or ultraviolet drying.

In other words, the drying rate cannot be increased beyond a certain limit, or the drying rate decreases even more when additional substances (for example, white pigments such as titanium oxide) are added to increase the practical value. bring about results. The present invention provides a new desensitizer having a photopolymerizable unsaturated group in place of the conventionally known polymerizable inert desensitizer,
The present invention makes it possible to solve the above-mentioned problems.

That is, since the desensitizer itself can be polymerized, the drying speed of the desensitizing ink made from it has become faster than ever before. In addition, conventionally, if the molecular weight is not 500 or more, other parts may be desensitized due to migration (see JP-A-47-329 ratio), and even if the molecular weight is quite large, the amount of coating may be large. When exposed to heat, humidity, etc., migration to other substances may occur.

Furthermore, since the desensitizer (or varnish containing the desensitizer) is a liquid and exists on the surface of the paper, when writing or stamping on the desensitized printing area with a ballpoint pen, fountain pen, stamp ink, etc., the ink There was a problem that the images were blurred and difficult to see.

Since the desensitizer according to the present invention is cured and becomes (almost) solid after being printed on paper, it does not cause problems with the above-mentioned migration and ink bleeding, and the molecular weight of the raw material is also low. It has the advantage that small items can also be used. Since the desensitizer according to the present invention has an unsaturated double bond,
Of course, it can be used as a desensitizer, but it can also be used in the form of a prepolymer by polymerizing it or with other monomers.

The proportion of the desensitizer in the ink solid molecules is 25%.
~80% is suitable, and ink containing pigments, resins, varnishes, various additives, etc. can be prepared by known methods.

The new desensitizer provided by the present invention is selected from the group of compounds expressed below.

That is, the general formula (wherein R1 and R2 are groups selected from hydrogen and methyl groups, and R3 is a group selected from hydrogen, methyl groups, acryloyl groups, methacryloyl groups, and higher alkyl group-substituted phenyl groups) , A is
There are 11 groups selected from.

In general, n is a number with an average, so it is not clear exactly, but when n is 2 or more, a desensitizing effect is shown, but when n≧4, the desensitizing effect becomes even stronger.

Many of these compounds are already commercially available from chemical manufacturers involved in oleochemical products and can be used immediately.

Alternatively, the terminal hydroxyl group of the corresponding polyoxyalkylene compound may be esterified by a conventional method to form an acrylic ester or a methacrylic ester. To actually prepare desensitizing ink using these new desensitizers,
There are various methods such as:

1 When used in place of conventionally known desensitizers 1-1 Conventional desensitized ink (i.e., for conventional printing systems that are not UV-curable systems) 1-2 Mixed with a UV-curable vehicle (photosensitive vehicle) 2 UV-curable desensitizing ink containing an ultraviolet curing agent (photosensitive monomer or photosensitive prepolymer) and a desensitizer. Sensitizers exhibit a remarkable drying accelerating effect in all of the above cases, and also have a sufficiently large desensitizing effect.

In particular, cases 1-2 and 2 are found to have the greatest practical utility. [This means that the decrease in polymerization rate and degree of polymerization due to dilution with a polymerization inert desensitizer (corresponding to the effect of a solvent in solution polymerization) becomes more pronounced with the introduction of a polymerizable desensitizer. It would be reasonable to assume that this is covered by ] Although it can be applied to any printing method, it is particularly useful in ultraviolet curing letterpress (letterpress) printing systems.

However, there are no particular restrictions on the method of using the desensitizer of the present invention, and it can be prepared into a desensitizer composition and applied to paper in the same manner as conventional desensitizers.

Carbonless pressure sensitive copying, for example, by direct application dissolved in a solvent such as alcohol, or by printing in the form of a printing ink suitable for letterpress (e.g. rubber letterpress), flexo, gravure, offset, etc. It may be applied to the surface of paper coated with an electron-accepting compound or solid acid, or to the surface of heat-sensitive recording paper. However, as described above, the features of the present invention can be best utilized when applied to an ultraviolet curing printing system. Even in conventional printing methods that do not use ultraviolet drying methods, the ink is exposed to room light after printing and hardens due to natural oxidation. It can be expected that the mechanical strength of the ink film after drying will increase.

In addition, in the printing industry, the term "dry" refers to the state in which the ink on the printed area is no longer sticky. Therefore, if the solvent has sufficiently vaporized and evaporated, if the ink has sufficiently penetrated into the paper, then if the ink has sufficiently penetrated the paper, If the liquid ink solidifies, or 4
It is well known that when this occurs in combination, it is used in this sense in the present application. In this application, the effects of the present invention have been described in terms of photocuring or ultraviolet drying, but the energy that should be irradiated onto the printed surface is not limited to light (ultraviolet), and electron beams and radiation are also used today. It is possible, and therefore, the effects of the present invention can be exhibited even when such a radiation source is used, and its usefulness is wide-ranging. Next, embodiments of the present invention will be explained in more detail with reference to Examples.

Example 1 The above compound NO. 16 (4) parts (NK ester P-? manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) (parts by weight, same hereinafter) Aron KR (manufactured by Toagosei Co., Ltd., ketone resin) 25 parts Titanium oxide
25 parts were mixed to prepare a desensitized ink.

Example 2 Aron KR Kabe polypropylene glycol (molecular weight 1.000)
Kabe Said Compound N
O. l3 Hakube (NK Ester 2 manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)
3G) Titanium oxide additive was mixed to prepare a desensitizing ink.

Example 3 The above compound NO. 12 (4) parts (NK ester 14G) Aron KR 25 parts Titanium oxide
25 parts were mixed to prepare a desensitizing ink.

Example 4 The above compound NO. 13O part trimethylolpropane trimethacrylate
Titanium dioxide
4(2) was mixed to prepare a desensitized ink.

Example 5 The above compound NO. l63 (2) Aron KR Kabe: Mix 2 parts of the above compound NOl3 (to) part titanium oxide,
A desensitizing ink was prepared.

Example 6 The five types of desensitizing inks described above were applied to the resin surface of commercially available non-carphone pressure-sensitive copying paper (Mitsubishi NCR paper 8, N-40 resin) in a mound of about 3 gId, and air-dried. Thereafter, a pressure-sensitive copying paper was placed on top of the paper and printed using a typewriter to test the desensitization ability.

In both cases, the coloring ability of the resin surface of the inner paper was sufficiently inhibited.

Further, no deterioration of the capsule surface of the inner paper was observed.

Example 7 Reaction product of epoxidized soybean oil acrylate and acrylated irisyanate 37 parts Compound NO. l8(9) part titanium oxide
Benzoin methyl ether (sensitizer)
An ink was prepared by blending 3 parts in a conventional manner.

Claims (1)

[Claims] 1 General formula ▲ Numerical formulas, chemical formulas, tables, etc. and higher alkyl group-substituted phenyl groups, A is a group selected from ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ and ▲ There are mathematical formulas, chemical formulas, tables, etc. A positive integer, m represents o or 1, respectively) is a polyoxyalkylene terminal unsaturated carboxylic acid ester chain
A desensitizer for carbonless pressure-sensitive copying paper that uses a novolac type phenol resin as a color developer, characterized in that it is composed of one or more nitrogen-free compounds in the molecule.