JPH0123510B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to printing inks, and more specifically, to printing inks that provide excellent ink drying properties and printing workability when printing on various printing materials. .

(Prior Art) Conventionally, various printing inks have been known for imparting designs to various printing materials.

For example, for printing on non-absorbent printing materials such as plastic film, metal, and glass, solvent evaporation printing inks are used, which dry by evaporation of the solvent they contain; Printing inks that dry by absorbing the solvent they contain, such as lithographic printing inks, intaglio printing inks, letterpress printing inks, and silk screen printing inks, are known for printing on flexible printing materials.

The various printing inks mentioned above apply ink to the surface of a printing plate according to the respective printing format, transfer the applied ink to the printing material, and
The printing ink is set by drying the varnish by evaporation of the solvent, absorption of the solvent, oxidative polymerization of the varnish, etc. Therefore, it is preferable that these printing inks dry quickly after being transferred.

Conventionally, methods for increasing the drying rate of printing inks, particularly oxidative polymerization type printing inks, include (1) a method of adding a metal salt of a fatty acid, commonly referred to as a dryer;

(2) A method of using a highly unsaturated drying oil as the unsaturated component of the varnish.

(3) A method in which the varnish is polymerized to some extent in advance.

(4) A method of heating printed matter during or after printing.

etc. are used.

However, if a large amount of dryer is added in the method (1) above, the varnish will be strongly colored due to the dryer, resulting in loss of color clarity of printing ink and printed matter, and the relationship between printing ink and dampening water. Since the balance is disrupted, it is impossible to use more than a certain amount, and there is a limit to the improvement of drying speed.

Method (2) also improves the drying speed, but if a highly unsaturated drying oil is used, a bad odor will be generated when the printing ink dries, the light resistance of the printed matter will decrease, and the surface of the ink film will lose its smoothness. Other drawbacks occur, such as decreased gloss, decreased strength of the ink film, high cost, and uneven quality.

In method (3), the unsaturated bonds in the varnish are naturally reduced due to prepolymerization, and the drying rate is not substantially improved.

Method (4) not only increases equipment costs, but also causes expansion and contraction of the printing material due to changes in humidity, reducing the dimensional accuracy of the printing material, making it unsuitable for precision printing.

Various problems arise.

Conventional printing inks are therefore designed not to suffer from the above-mentioned drawbacks and generally require a time period of about 12 to 48 hours to achieve sufficient drying. On the other hand, the performance of printing equipment has improved markedly, and excellent high-speed printing machines have been developed.However, due to the insufficient drying speed of conventional printing inks as mentioned above, workability after printing is low, and the performance of printing machines has deteriorated. Printing workability after printing is increasingly becoming a problem in that it is not able to perform to its full potential.

Methods to improve printing workability include spraying powder on the printing surface immediately after printing to prevent printing ink set-off and blocking, or stacking many printed materials to prevent printing ink set-off and blocking. Therefore, methods are being used to limit the number of stacked sheets.

Therefore, there is a strong demand for measures to increase the drying speed of printing ink without causing the various problems described above, to omit the complicated operations described above, and to improve printing workability.

In order to solve the above-mentioned problems of the conventional technology and meet the demands of the above-mentioned industry, the inventors of the present invention have conducted extensive research and found that a specific unsaturated component is used as part or all of the unsaturated components of conventional printing ink varnish. The present invention was developed based on the finding that by doing so, a printing ink having an excellent drying speed can be obtained without causing the various problems described above, and as a result, printing workability after printing is significantly improved. completed.

(Means for Solving the Problems) That is, the present invention provides a printing ink consisting of a colorant and a varnish, in which a part or all of the unsaturated components of the varnish contain a polyhydric alcohol of 4 or more hydrides and an unsaturated fatty acid. This is a printing ink characterized by being an ester of

Next, to explain the present invention in more detail, the main feature of the present invention is that an ester of a polyhydric alcohol having a valence of 4 or more and an unsaturated fatty acid is used as part or all of the unsaturated component of the varnish of the printing ink. Because of this feature, the object of the present invention has been achieved.

As the polyhydric alcohol of 4 or more hydrides used in the present invention to obtain the specific ester that mainly characterizes the present invention, any of the conventionally known polyhydric alcohols of 4 or more hydrides can be used, and for example, preferred ones can be used. Examples include polyglycerin such as diglycerin and triglycerin, erythritol, D
-, L- or rac-trait, pentaerythritol (pentaerythritol), adonite,
D-, L- or rac-arabitol, xyrite, aritto, D-, L- or
rac-talitz (talitol), D-, L- or
Polyhydric alcohols such as rac-sorbit (sorbitol), D-, L- or rac-mannitol (mannitol), lactose, polymers such as dimers and trimers of these polyhydric alcohols, and polyhydric alcohols such as these. Low molecular weight polyhydric alcohols such as ester oligomers with terminal hydroxyl groups and dibasic acids, sugars such as various cellulose derivatives, low molecular weight polyvinyl alcohols, partially saponified products of polyvinyl acetate, copolymers of vinyl acetate and other monomers Examples include saponified products of, high-molecular polyhydric alcohols such as hydroxyl-modified acrylic resins, and lower fatty acid esters of these low-molecular to high-molecular polyhydric alcohols.

Particularly preferred are low-molecular polyhydric alcohols with a valence of 5 or more or derivatives thereof.

Any conventionally known unsaturated fatty acids can be used as the unsaturated fatty acids that form esters with the above-mentioned polyhydric alcohols, such as caproleic acid, lauroleic acid, myristoleic acid, palmitoleic acid, oleic acid, elaidic acid, Medium to sorbic acid, linoleic acid, linolenic acid, stearolic acid, eleostearic acid, ricinoleic acid, arachidonic acid, culpanodonic acid, abietic acid, etc.
Higher unsaturated fatty acids, hemp seed oil, linseed oil, soybean oil, safflower oil, linseed oil, Japanese tung oil, sunflower oil, eno oil, hempseed oil, tall oil, sesame oil,
Wheat germ oil, corn oil, rapeseed oil, rice bran oil, dehydrated castor oil, cottonseed oil, squid oil, fish oil,
Mixed unsaturated fatty acids obtained from whale oil and the like are useful.

Any conventionally known method can be used to obtain an ester from the polyhydric alcohol with a valence of 4 or more and the unsaturated fatty acid. Preferred methods include a method in which glycerin is removed from the above-mentioned polyhydric alcohol having a valence of 4 or more and the above-mentioned drying oil and/or semi-drying oil by transesterification.

Specifically, a polyhydric alcohol and an unsaturated fatty acid (or the above fats and oils) are mixed at about 100 to 360°C in the presence or absence of an organic solvent, optionally in the presence of a catalyst, preferably under reduced pressure. It can be obtained by dehydration condensation or transesterification for about 0.5 to 24 hours.

In such ester production, it is not necessarily necessary that all the hydroxyl groups of the polyhydric alcohol be esterified, and preferably about three (on average) or more may be esterified. Furthermore, an ester may be formed by using a portion of a saturated fatty acid or a non-drying oil in combination with the unsaturated fatty acid or drying oil and/or semi-drying oil as described above. When such saturated fatty acids and the like are used together, it is suitable that the number of unsaturated fatty acid groups in the formed ester is 3 or more, preferably 4 or more per mole of ester.

A feature of the present invention is that the ester of polyhydric alcohol and unsaturated fatty acid as described above is used as an unsaturated component of the varnish of the printing ink. It may be used as all of the unsaturated components, or may be used in combination with conventionally known varnish components. When used in combination with conventionally known varnish components,
It is necessary that the above-mentioned ester accounts for 5% by weight or more, preferably 10% by weight or more in the entire varnish component, and if the amount used is 5% by weight or less, a high drying rate, which is the intended purpose of the present invention, can be achieved. It is difficult to do so.

In addition to the above-mentioned drying oil and/or semi-drying oil, any conventionally known varnish component that can be used in combination can be used.

The amount of varnish used in the present invention as described above is the same as that of conventional printing inks, and is, for example, about 50 to 80 parts by weight in 100 parts by weight of printing ink.

The printing ink of the present invention may be similar to the prior art except that the above-mentioned specific esters are used as all or part of the unsaturated components of the varnish.

For example, the colorant constituting the printing ink of the present invention is a pigment or dye that is used in conventional printing ink, and any conventionally known pigment or dye can be used as it is as the colorant in the printing ink of the present invention. It is possible. Further, the amount used may be the same as that of conventionally known printing inks, for example,
It generally accounts for about 10 to 40 parts by weight, for example, in 100 parts by weight of printing ink.

The printing ink of the present invention has the above-mentioned colorant and varnish as the main constituent materials, and other conventionally known additives such as an ink solvent, a dryer, a leveling improver, a thickener, an anti-skinning agent, etc. Both can be used.

For example, ink solvents affect ink viscosity, consistency,
It is added to correct the flow, etc., and any of the various organic solvents conventionally used for printing ink, such as light oil, spindle oil, various ink solvents, and machine oil, can be used. The amount used is generally about 5 to 80 parts by weight per 100 parts by weight of printing ink.

For dryers, salts of polyvalent metals such as cobalt, manganese, cerium, zirconium, lead, iron, zinc, copper, vanadium, barium, and calcium and oil-soluble carboxylic acids such as naphthenic acid, octylic acid, resin acid, and tall oil are used. etc., and these dryers contain approximately 0.005 parts by weight of metal in 100 parts by weight of printing ink.
It is generally used in a proportion of ~0.5% by weight.

(Function/Effect) According to the present invention as described above, the drying speed of the printing ink of the present invention is higher than that of conventionally known printing inks of the same type, with the same amount of dryer used and no special The drying speed is about 1 to 5 hours, compared to about 6 to 24 hours for conventional methods.
The time has been significantly reduced. Moreover, even if the drying time is shortened in this way, the problems caused by the addition of a large amount of dryer, the problems caused by using a varnish with a high degree of unsaturation, and other problems as in the prior art described above do not occur. Ta.

Although the rationale for such a significant improvement in drying speed in the present invention is not precisely known,
According to the inventor's imagination, the specific ester used in the present invention is such that all or a part of the glycerin in the drying oil and/or semi-drying oil is replaced with a polyhydric alcohol having a valence of 4 or more, preferably 5 or more. As a result, more than three unsaturated fatty acids are bound in one ester molecule, so the polymerization rate is significantly higher than that of conventional printing ink varnish even when using the same amount of dryer. It is increasing,
It is also believed that when used in combination with conventionally known varnishes, these specific esters also accelerate the polymerization rate of the varnish used in combination.

Therefore, according to the invention, the printing ink of the invention is superior because it has a significantly higher drying rate than that of conventional printing inks even when using a similar amount of dryer as conventional printing inks. In addition to being able to provide printed matter of high quality, various complicated post-printing operations as in the prior art are improved, and excellent printing workability is provided.

Next, the present invention will be explained in more detail with reference to Examples. In addition, parts and percentages in the text are based on weight unless otherwise specified.

Example 1 37 parts of D-sorbitol and tall oil fatty acid (acid value
194) and 232 parts were heated to 230°C and 17.2 parts of water was distilled off to synthesize an ester. Then this reaction product
80 parts, rosin modified phenolic resin (softening point 170℃,
Acid value 19) 80 parts and No. 5 solvent 80 parts to 220
The mixture was heated at ℃ for 1 hour to form a varnish.

20 parts of Briant Carmine 6B was added to 80 parts of this varnish and kneaded in with a triple roll, and then 1 part of manganese naphthenate was mixed to obtain the printing ink of the present invention. When the drying time of this printing ink was measured at 20°C, it was 3 hours and 15 minutes.

Examples 2 to 4 Printing inks of the present invention were obtained in the same manner as in Example 1, except that polyhydric alcohols having a valence of 4 or more as shown in Table 1 below were used instead of D-sorbitol used in Example 1. The drying time of the printing ink was measured in the same manner as in Example 1, and the results were as shown in Table 1 below.

Table 1 Example 2 Polyhydric alcohol and its usage amount Polyglycerin 46 parts Water distillation amount 17 parts Drying time 4 hours 30 minutes Example 3 Polyhydric alcohol and its usage amount Pentaerythritol 8 parts Water distillation amount 17.4 parts Drying Time 3 hours 30 minutes Example 4 Polyhydric alcohol and its usage amount Lactose (combined with 100 parts of ethanol as a solvent) 16 parts Water distillation amount 16 parts Drying time 3 hours Example 5 136 parts of pentaerythritol and 1000 parts of linseed oil Glycerin is heated to about 230-330℃ for 6 hours
52 copies were collected. Example 1 using this product
The printing ink of the present invention was obtained in the same manner as in Example 1.
When the drying time of the printing ink was measured in the same manner as above, it was 2 hours.

Example 6 64 parts of glycerin was distilled out in the same manner as in Example 5 except that 100 parts of polyglycerin was used instead of pentaerythritol. Using this reaction product,
Otherwise, the printing ink of the present invention was obtained in the same manner as in Example 1, and the drying time of the printing ink was measured in the same manner as in Example 1, and the drying time was 1 hour and 45 minutes.

Comparative Example 1 A comparative printing ink was obtained by using the same amount of linseed oil in place of the reaction product of Example 1, and the drying time was measured in the same manner as in Example, and found to be 8 hours and 30 minutes.

Comparative Example 2 A comparative printing ink was obtained in the same manner as in Example 1, except that 32 parts of glycerin was used in place of D-sorbitol in Example 1, and 17.5 parts of water was distilled out. The drying time of the printing ink was measured and was over 12 hours.

As described above, it is clear that the drying speed of the printing ink of the present invention is significantly higher than that of conventional printing inks.

Claims (1)

[Claims] 1. A printing ink consisting of a colorant and a varnish, characterized in that a part or all of the unsaturated components of the varnish are esters of a polyhydric alcohol with a valence of 4 or more and an unsaturated fatty acid. printing ink. 2. The printing ink according to claim 1, wherein the unsaturated fatty acid is a drying oil and/or a semi-drying oil fatty acid. 3. The ester of a polyhydric alcohol with a valence of 4 or more and an unsaturated fatty acid is an ester obtained by transesterifying a part or all of the glycerin of a drying oil and/or semi-drying oil with a polyhydric alcohol of a hydration of 4 or more. A printing ink according to claim 1. 4. The printing ink according to claim 1, wherein three or more of the hydroxyl groups of the polyhydric alcohol having a valence of 4 or more are esterified. 5. The printing ink according to claim 1, wherein the polyhydric alcohol is a polyhydric alcohol with a valence of 5 or more.