JPH0123509B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a printing ink, and more specifically, the present invention relates to a printing ink that provides excellent ink drying properties and printing workability when printing on various printing materials, and furthermore, The purpose of the present invention is to provide a printing ink capable of printing with excellent gloss.

(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; Absorption of the solvent contained and/or
or printing inks that dry by oxidative polymerization of varnish, such as lithographic printing inks, intaglio printing inks,
Letterpress printing inks, silk screen printing inks, etc. are known.

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 speed of printing inks, especially oxidative polymerization type printing inks, include (1) adding metal salts of fatty acids, commonly referred to as dryers, and (2) adding unsaturated components to varnishes. (3) Prepolymerizing the varnish to some extent; and (4) heating the printed material during or after printing.

(Problem to be Solved by the Invention) However, when a large amount of dryer is added in the method (1) above, the varnish is strongly colored due to the dryer, resulting in poor color clarity and gloss of printing ink and printed matter. Since the printing ink and dampening water are damaged and the balance between printing ink and dampening water 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 occur when the printing ink dries, and the light resistance of the printed matter will decrease.
Other drawbacks occur, such as the surface of the ink film losing its smoothness and the gloss of the ink film being reduced, the strength of the ink film being reduced, the cost being high, and the quality being inconsistent.

In method (3), the number of unsaturated bonds in the varnish naturally decreases 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 to avoid the above-mentioned drawbacks and generally require a long period of time, about 6 to 24 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 is Printing workability after printing is increasingly becoming a problem in that it is not able to perform to its full potential.

As a method to improve printing workability, there is a method to spray powder on the printing surface immediately after printing to prevent printing ink set-off and blocking, or a method to prevent printing ink set-off and blocking when many printed sheets are piled up. Therefore, methods have been used to limit the number of stacked sheets, but these methods are extremely complicated and increase the total cost of printing.

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. By doing so, a printing ink with excellent drying speed can be obtained without causing the various problems mentioned above, and as a result, printing workability after printing is significantly improved without losing the gloss of the ink film. The present invention was completed based on the knowledge that

(Means for Solving the Problems) That is, the present invention provides a printing ink comprising a colorant and a varnish, in which part or all of the unsaturated components of the varnish are maleic anhydride/styrene modified with an unsaturated alcohol. This is a printing ink characterized by being a copolymer.

Next, to explain the present invention in more detail, the main feature of the present invention is that a maleic anhydride/styrene copolymer modified with an unsaturated alcohol is used as part or all of the unsaturated component of the varnish of the printing ink. Because of this characteristic, the object of the present invention has been achieved.

The unsaturated alcohol-modified maleic anhydride/styrene copolymer used in the present invention and which mainly characterizes the present invention is maleic anhydride/styrene copolymer.
It is made by reacting the acid anhydride group of a styrene copolymer with an unsaturated alcohol.

Conventionally, maleic anhydride/styrene copolymers were
It is water-soluble, alkali water-soluble, amine water-soluble, alcohol-soluble, etc., and is used as a varnish component in water-based gravure ink, water-based flexo ink, etc., and is also used as a varnish component of maleic anhydride/styrene copolymer modified with lower alcohol, etc. However, these maleic anhydride/styrene copolymers or their lower alcohol modified products are all hydrophilic, so they can be used for offset printing inks that require high hydrophobicity and water repellency. It could not be used at all as a varnish component.

However, according to the inventor's detailed research,
Hydrophilicity can be improved by modifying the maleic anhydride/styrene copolymer as described above with an unsaturated alcohol having a certain number of carbon atoms, preferably 5 or more carbon atoms, more preferably 6 to 22 carbon atoms. It was discovered that the hydrophobic properties of the varnish are suitable for use as a varnish component in offset printing inks, and that they can be used as varnish components in offset printing inks.

Furthermore, when this maleic anhydride/styrene copolymer modified with an unsaturated alcohol is used as a varnish component in offset printing ink, it can be used as a varnish component in offset printing inks, which have been widely used in the past, such as printing inks containing drying oils or modified drying oils as varnish components. The inventors have discovered that they can provide an excellent printing ink that exhibits even more excellent drying properties than those of conventional inks, and does not impair the gloss of its film, unlike conventional inks, even though it dries quickly.

The maleic anhydride/styrene copolymer used to obtain such a modified maleic anhydride/styrene copolymer is obtained by a copolymerization method using maleic anhydride and styrene as main monomers ( In addition, the above "styrene" refers to not only styrene monomers but also α-chlorostyrene, α
-Methylstyrene, halogen atom in phenyl group,
It also includes styrene derivatives having substituents such as alkyl groups such as methyl groups and ethyl groups, and substituents such as nitro groups. ). Furthermore, these copolymers may be terpolymers consisting of maleic anhydride and monomers other than styrene, such as other vinyl monomers such as ethylene, propylene, vinyl acetate, vinyl chloride, (meth)acrylic esters, etc.

Many such maleic anhydride/styrene copolymers are already known, and maleic anhydride/styrene copolymers with different copolymerization ratios of each monomer are easily available on the market, and any of them can be used in the present invention. Can be done.

A particularly preferred maleic anhydride/styrene copolymer in the present invention is a copolymer in which the copolymerization ratio of maleic anhydride and styrene is 0.5 mol to 3 mol of styrene per mol of maleic anhydride. .

The unsaturated alcohol to be reacted with the above maleic anhydride/styrene copolymer is one having at least one unsaturated double bond and at least one hydroxyl group in its structure, and is suitable in the present invention. Examples include the following:

(1) Aliphatic unsaturated alcohol having 5 or more carbon atoms For example, 2-hexenol 1,2-heptynol-1,2-octenol-1,2-undecenol-1,2-tetradecenol-1,2-pentadecenol-1 ,2-hexadecenol-1,
2-Heptadecenol-1,2-octadecenol-1,5-hexenol-1,6-heptenol-1,10-undecenol-1,11-dodecenol-1,12-tridecenol-1,15-hexadecenol-1, oleyl alcohol , elaidyl alcohol, linoleyl alcohol, linolenyl alcohol, eleostearyl alcohol, ricinoleyl alcohol, etc. Particularly preferred are unsaturated alcohols having 12 to 22 carbon atoms.

(2) Ester alcohols having at least one hydroxyl group consisting of a saturated polyhydric alcohol and an unsaturated fatty acid These ester alcohols are ester alcohols formed by leaving at least one hydroxyl group of a saturated polyhydric alcohol; Examples of saturated polyhydric alcohols used for alcohol include ethylene glycol, propylene glycol, butanediol, pentanediol,
Hexanediol, heptanediol, octanediol, nonanediol, decanediol, undecanediol, dodecanediol, tridecanediol, tetradecanediol, pentadecanediol, hexadecanediol, heptadecanediol, octadecanediol, nonadecanediol, eicosanediol, diethylene glycol , dihydric alcohols such as triethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, polyprolene glycol; trihydric alcohols such as glycerin, butanetriol, 2-methylpropanetriol, hexanetriol; diglycerin, triglycerin, etc. polyglycerin, erythritol, D-, L- or rac-trait, pentaerythritol (pentaerythritol), adonite, D-, L- or rac-arabitol (arabitol), xylitol, aritz, D-, L-
or rac-Talitto (Talitol), D-, L-
or rac-sorbitol, D-,
Examples include polyhydric alcohols such as L- or rac-mannitol (mannitol) and lactose. Particularly preferred are low molecular weight di- or trivalent polyhydric alcohols or derivatives thereof.

Any conventionally known unsaturated fatty acids can be used as the unsaturated fatty acids that form esters with the above-mentioned saturated polyhydric alcohols, but examples include caproleic acid, lauroleic acid, myristoleic acid, palmitoleic acid, oleic acid, and elaidic acid. , sorbic acid, linoleic acid, linolenic acid, stearolic acid, eleostearic acid, ricinoleic acid, arachidonic acid, kurpanodonic acid, abietic acid, etc.
Higher unsaturated fatty acids, flaxseed oil, soybean oil, safflower oil, sinensis 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 Mixed unsaturated fatty acids obtained from castor oil, cottonseed oil, squid oil, fish oil, whale oil, etc. are useful. Among these, particularly preferred are unsaturated fatty acids having 14 to 22 carbon atoms.

Any conventionally known method can be used to obtain the ester alcohol from the saturated polyhydric alcohol and the unsaturated fatty acid, such as reacting the saturated polyhydric alcohol with the unsaturated fatty acid. A preferred method is a method in which glycerin is removed from the above-mentioned saturated polyhydric alcohol and the above-mentioned drying oil and/or semi-drying oil by transesterification.

Specifically, a saturated polyhydric alcohol and an unsaturated fatty acid (or the above fats and oils) are mixed in the presence or absence of an organic solvent, optionally in the presence of a catalyst, and optionally under reduced pressure for approximately 100% ~0.1~ at ~320℃
It can be obtained by performing dehydration condensation or transesterification for about 4 hours.

In producing such an ester alcohol, it is necessary not to esterify all the hydroxyl groups of the polyhydric alcohol, but to leave at least one hydroxyl group.

It is also possible to prepare fatty acid diglyceride from the above drying oil or semi-drying oil and use it as the unsaturated ester alcohol.

(3) Hydroxyl group-containing unsaturated fatty acids or alcohol esters thereof, such as propenyl glycolic acid, parasorbic acid, β-oxyhydrosorbic acid, ambrettolic acid, isoambrectulic acid, ricinoleic acid,
Examples include lysieraidic acid, oxynarboxic acid, camolene acid, and esters of these with saturated aliphatic alcohols or unsaturated aliphatic alcohols.

Among the unsaturated alcohols mentioned above, those having a total carbon number of 5 or more are particularly preferred in the present invention, and the most preferred are those having a total carbon number of 6 to 22.
belongs to.

The reaction between the above-mentioned maleic anhydride/styrene copolymer and the above-mentioned unsaturated alcohol can be carried out according to a conventional method, for example, in an inert organic solvent or without a solvent, if necessary in the presence of a catalyst. It is obtained by reacting both at a temperature of about 100 to 220°C for about 0.01 to 5 hours. A particularly preferred method is to use an excess of unsaturated alcohol as a solvent, and when the reaction has proceeded to a predetermined extent, the excess unsaturated alcohol is distilled off, preferably under reduced pressure.

The reaction ratio of the unsaturated alcohol to the maleic anhydride/styrene copolymer is determined so that the resulting modified product is sufficiently hydrophobic. For example, if the unsaturated alcohol is a long-chain alcohol with a relatively large number of carbon atoms, a relatively small proportion may be used, and if the unsaturated alcohol is a relatively short-chain alcohol, it may be used in a higher proportion to obtain a modified product. The hydrophobicity of can be adjusted to a desired range. Generally, about 50 to 2 parts per 100 parts by weight of maleic anhydride/styrene copolymer,
Preferably, 000 parts by weight of unsaturated alcohol are reacted.

A feature of the present invention is to use the unsaturated alcohol-modified maleic anhydride/styrene copolymer as described above as an unsaturated component of a varnish for printing ink. It may be used as all the unsaturated components of the varnish, or it 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 modified substances account for 10% by weight or more, preferably 30% by weight or more of the total varnish component, and if the amount used is 10% by weight or less, the It is difficult to achieve high drying rates and high coating gloss, which are the intended objectives of the invention.

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 modified product is used as all or part of the unsaturated component 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. Yes, the amount used is printing ink 100
It generally accounts for about 5 to 80 parts by weight.

For dryers, salts of polyvalent metals such as cobalt, manganese, cerium, zirconium, lead, iron, zinc, copper, vanadium, barium, calcium, and oil-soluble carboxylic acids such as naphthenic acid, octylic acid, resin acid, tall oil, etc. 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 of the conventional method is about 6 to 24 hours, while the drying speed is about 1 to 24 hours.
The time has been significantly shortened to 5 hours. Moreover, even if the drying time is shortened in this way, there are problems caused by the addition of a large amount of dryer as in the prior art as described above.
Prints with high coating gloss can be provided without any of the problems associated with using highly unsaturated varnishes and other problems.

In addition, in the present invention, the maleic anhydride/styrene copolymer, which is the raw material for the modified product used in the present invention, is stably supplied with industrially constant quality, so it can be used as a natural Problems such as variations in quality due to unstable product quality and unstable supply are also satisfactorily resolved.

Therefore, according to the invention, the printing ink of the invention has a drying rate significantly higher than that of conventional printing inks without any loss in print quality, even when using a similar amount of dryer as in conventional printing inks. Since it has a drying speed, it is possible to provide printed matter of excellent quality, and various complicated post-printing operations as in the prior art are improved, thereby providing excellent printing workability.

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 Tall oil fatty acid and triethylene glycol (molar ratio 1:1.05) were azeotropically dehydrated in xylene, and after dehydration, xylene was distilled off to obtain ester alcohol with a reaction rate of 99%. This ester alcohol 350
50 parts of a maleic anhydride/styrene copolymer (copolymerization ratio, maleic anhydride:styrene = 1:1) dissolved in 70 parts of ethanol was added to the mixture, and the mixture was heated to 200°C for 30 minutes.

80 parts of the modified product obtained above, 80 parts of rosin-modified phenolic resin (softening point 170°C, acid value 19) and 5
A varnish was prepared by heating 80 parts of No. Solvent at 220°C for 1 hour.

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 6 Printing inks of the present invention were obtained in the same manner as in Example 1 except that unsaturated alcohols shown in Table 1 below were used in place of the ester alcohol used in Example 1. Similarly, the drying time of the printing ink was measured and the results were as shown in Table 1 below.

Table 1 Example 2 Unsaturated alcohol modified product and its usage amount Oleyl alcohol modified product 46 parts Drying time 4 hours 30 minutes Example 3 Unsaturated alcohol modified product and its usage amount Elaidyl alcohol modified product 18 parts Drying time 3 hours 30 minutes Example 4 Unsaturated alcohol modified product and its usage amount Linoleyl alcohol modified product 26 parts Drying time 3 hours Example 5 Unsaturated alcohol modified product and its usage amount Tall oil fatty acid and diethylene glycol (molar ratio: 1:1.05) Modified product by condensation product with 33 parts Drying time: 3 hours Example 6 Unsaturated alcohol modified product and its usage amount Modified product by alcoholysis of 1000 parts of linseed oil with 250 parts of diethylene glycol monobutyl ether 23 parts Drying time: 3 hours Example 7 Instead of the maleic anhydride/styrene copolymer in Example 5, maleic anhydride/styrene copolymer (copolymerization ratio, maleic anhydride:styrene =
The printing ink of the present invention was obtained in the same manner as in Example 1, except that the drying time of the printing ink was measured in the same manner as in Example 1, and was found to be 3 hours and 45 minutes.

Example 8 Instead of the maleic anhydride/styrene copolymer in Example 5, maleic anhydride/styrene copolymer (copolymerization ratio, maleic anhydride:styrene =
The printing ink of the present invention was obtained in the same manner as in Example 1 except that the drying time of the printing ink was measured in the same manner as in Example 1, and it was found to be 4 hours.

Comparative Example 1 A comparative printing ink was obtained by using the same amount of linseed oil in place of the modified product of Example 1, and the drying time was measured in the same manner as in the 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 the same amount of glycerin ester of tall oil fatty acid was used in place of the modified product in Example 1, and the drying time of this printing ink was measured. However, it 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 maleic anhydride/styrene copolymer modified with an unsaturated alcohol. printing ink. 2. The printing ink according to claim 1, wherein the unsaturated alcohol is an aliphatic unsaturated alcohol having 5 or more carbon atoms. 3. Claim 1, wherein the unsaturated alcohol is an ester alcohol containing at least one hydroxyl group of a saturated polyhydric alcohol and an unsaturated fatty acid.
Printing inks listed in section. 4. The printing ink according to claim 1, wherein the unsaturated alcohol is a hydroxyl group-containing unsaturated fatty acid or an alcohol ester thereof. 5. The printing ink according to claim 3 or 4, wherein the unsaturated alcohol has 6 or more carbon atoms.