JP2006282776A - Ink for lithography - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain ink for lithography which develops an excellent antiblocking effect in an environment liable to cause blocking phenomena in the case of receiving load or heat history. <P>SOLUTION: The ink for lithography comprises <15 wt.% of a petroleum-based solvent and 0.01-5 wt.% of an organopolysiloxane. The ink for lithography comprises further an amino-modified organopolysiloxane. The printed article is obtained by using the ink for lithography. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lithographic printing ink that can exhibit a good anti-blocking effect in an environment where a blocking phenomenon is likely to occur, such as when receiving a load or a thermal history.

Lithographic printing uses a printing machine or the like and transfers it to a printing medium such as paper or film to form an image.
After printing, if blocking occurs in an environment that tends to cause a blocking phenomenon such as when the printed material receives a load or heat history, the quality of the printed material is greatly affected.

  The lithographic printing ink is obtained by dispersing a pigment in a binder made of synthetic resin, vegetable oil, petroleum solvent or the like. To meet recent environmental regulations (Eco Mark, Japan-India Green Standard, GPN, etc.), petroleum solvent 0-15% by weight or vegetable oil or vegetable oil-based solvent is 20% by weight or more or aromatic component of ink solvent It is recommended to use lithographic printing ink with a 1% by weight or less. When printing using such a lithographic printing ink, vegetable oil remains in the ink and the printing medium, and after printing, the printed matter is subject to a load or a thermal history, etc. It is known.

Under such circumstances, Japanese Patent Application Laid-Open No. 2-6570 adds 0.5 to 40% by weight of an anti-blocking agent having a polysiloxane-containing polymer to 100% by weight of the active ingredient of the ink. Although the method for preventing blocking is shown, the present invention is generally considered to be inferior in blocking resistance, less than 15% by weight of a petroleum-based solvent or 20% by weight or more of a solvent derived from vegetable oil or vegetable oil, or an ink solvent It imparts blocking resistance to a lithographic printing ink having an aromatic component of 1% by weight or less.
Japanese Patent Laid-Open No. 2-6570

  The object of the present invention is to provide an ink for lithographic printing which is imparted with blocking resistance against the problems of the prior art.

That is, the present invention relates to a lithographic printing ink characterized in that the content of petroleum solvent in the ink is less than 15% by weight and the organopolysiloxane is contained in an amount of 0.01 to 5% by weight.
The present invention also relates to a lithographic printing ink characterized in that the organopolysiloxane contains an amino-modified one.
The present invention also relates to the above lithographic printing ink, which contains 20% by weight or more of vegetable oil or a vegetable oil-derived solvent in the ink.
Furthermore, the present invention relates to the above lithographic printing ink, wherein the aromatic component of the ink solvent is less than 1% by weight.

  The lithographic printing ink provided by the present invention imparts blocking resistance even in inks with a low petroleum solvent content, which have been considered to have poor blocking resistance, by adding a polysiloxane-containing polymer. Became possible.

  The petroleum solvent used in the ink of the present invention has an aromatic hydrocarbon content of 1% by weight or less, an aniline point of 75 to 95 ° C, preferably 80 to 95 ° C, and a boiling point of 260 to 350 ° C, preferably 280. A petroleum solvent in the range of ˜350 ° C. is preferred. If the aniline point is less than 75 ° C, the ability to dissolve the resin is too high, which is not preferable because the setting property of the ink is slow, and if it exceeds 95 ° C, the solubility of the resin is poor. Meat etc. are bad and not preferable. When the boiling point is less than 260 ° C., the evaporation of the ink solvent on the printing machine increases, and the transferability of the ink to a roller, a blanket, a plate, etc. deteriorates due to the deterioration of the fluidity of the ink. Moreover, when it exceeds 350 degreeC, since drying of heat set type ink is inferior, it is unpreferable.

  Examples of the organopolysiloxane used in the present invention include dimethylpolysiloxane, methylphenylpolysiloxane, dimethylpolysiloxane modified with carboxylic acid, hydroxyl group, amino group, and the like, and methylphenylpolysiloxane. Furthermore, the use of amino-modified organopolysiloxane suppresses blocking due to effective interaction with functional groups derived from resins and oils on the ink film and reducing free energy on the surface. It is preferable at the point which expresses the effect to do.

  The addition amount of the organopolysiloxane is 0.01 to 5% by weight based on the whole ink. When the added amount is less than 0.01% by weight, the anti-blocking effect is unsatisfactory, and when it exceeds 5% by weight, it is unsuitable for post-processing suitability such as PP attachment.

  Examples of vegetable oils are those derived from vegetable oils such as palm kernel oil, coconut oil, cottonseed oil, peanut oil, palm oil, corn oil, olive oil, cucumber oil, tsukan oil seed oil, linseed oil, corn oil, soybean oil, safflower oil, etc. In addition, these thermal polymerization oils and oxygen-blown polymerization oils can also be used.

  As the main formulation of the ink of the present invention, a pigment, a synthetic resin, a vegetable oil, a petroleum solvent, and a gelling agent such as aluminum stearate and an aluminum chelate compound, if necessary, dissolved and reacted at 180 ° C to 240 ° C. And an anti-blocking agent characterized by having a silicone oil, that is, a polysiloxane-containing polymer.

  As the pigment used, a general organic pigment or the like is used. Commercially available products include LIONOL BLUE FG7330 manufactured by Toyo Ink Manufacturing Co., Ltd.

  As the synthetic resin, rosin-modified phenol resin, petroleum resin, alkyd resin, rosin-modified alkyd resin, and rosin ester can be considered. Preferably, rosin modified phenolic resin is used. The rosin-modified phenol resin is not particularly limited, but preferably has a weight average molecular weight of 10,000 to 300,000. If the rosin-modified phenolic resin is 10,000 or less, the ink has insufficient viscoelasticity, and if it is 400,000 or more, the fluidity as ink is insufficient. The cloudiness temperature of the rosin-modified phenol resin is preferably 10 ° C to 120 ° C. Below 10 ° C, the solubility is too good, so the setting is slow.

    Examples of vegetable oils are those derived from vegetable oils such as palm kernel oil, coconut oil, cottonseed oil, peanut oil, palm oil, corn oil, olive oil, cucumber oil, tsukan oil seed oil, linseed oil, corn oil, soybean oil, safflower oil, etc. In addition, these thermal polymerization oils and oxygen-blown polymerization oils can also be used.

[Example]
Next, the present invention will be described in more detail by way of specific examples, but the scope of the present invention is not limited to these described examples. In addition, the part of the following description represents a weight part and% represents weight%.

Example of rosin-modified phenolic resin A To a four-necked flask equipped with a stirrer, a cooler and a thermometer, 1000 parts of P-octylphenol, 850 parts of 35% formalin, 60 parts of 93% sodium hydroxide and 1000 parts of toluene were added. , Reacted at 90 ° C. for 6 hours. Then, 125 parts of 6N hydrochloric acid and 1000 parts of tap water were added, stirred and allowed to stand, and the upper layer part was taken out to obtain 2000 parts of a toluene solution of a resole type phenol resin having a nonvolatile content of 49%. It was. A four-necked flask equipped with a stirrer, a condenser with a water separator, and a thermometer was charged with 1000 parts of gum rosin, dissolved at 200 ° C. while blowing nitrogen gas, and 1800 parts of the resole solution produced above was added. After reacting at 230 ° C. for 4 hours while removing toluene, 110 parts of glycerin was added and reacted at 260 ° C. for 10 hours to obtain a rosin-modified phenol resin having a weight average molecular weight of 50000 with an acid value of 20 or less.

Example of rosin-modified phenolic resin B In a four-necked flask equipped with a stirrer, a condenser, and a thermometer, 1000 parts of P-tertiary butylphenol, 850 parts of 35% formalin, 60 parts of 93% sodium hydroxide, and 1000 parts of toluene In addition, the reaction was carried out at 90 ° C. for 6 hours. Then, 125 parts of 6N hydrochloric acid and 1000 parts of tap water were added, stirred and allowed to stand, and the upper layer part was taken out to obtain 2000 parts of a toluene solution of a resole type phenol resin having a nonvolatile content of 49%. It was. A four-necked flask equipped with a stirrer, a condenser with a water separator, and a thermometer was charged with 1200 parts of gum rosin, dissolved at 200 ° C. while blowing nitrogen gas, and 1800 parts of the resole solution produced above was added. After reacting at 230 ° C. for 4 hours while removing toluene, 110 parts of glycerin was charged and reacted at 260 ° C. for 15 hours to obtain a rosin-modified phenol resin having an acid value of 20 or less and a weight average molecular weight of 150,000.

Varnish Production Example A
Varnish A was obtained by heating and stirring 45 parts of rosin-modified phenol resin A, 30 parts of soybean oil, 524 parts of AF solvent 5 and 1 part of ALCH at 190 ° C. for 1 hour.

Varnish Production Example B
Varnish B was obtained by heating and stirring 45 parts of rosin-modified phenol resin A, 54 parts of soybean oil and 1 part of ALCH at 190 ° C. for 1 hour.

Varnish Production Example C
Varnish C was obtained by heating and stirring 45 parts of rosin-modified phenolic resin B, 54 parts of soybean oil and 1 part of ALCH at 190 ° C. for 1 hour.

Varnish Manufacturing Example D
Varnish D was obtained by heating and stirring 45 parts of rosin-modified phenol resin A, 10 parts of soybean oil, 444 parts of AF solvent 544, and 1 part of ALCH at 190 ° C. for 1 hour.

Varnish Production Example E
Varnish E was obtained by heating and stirring 45 parts of rosin-modified phenolic resin A, 554 parts of AF solvent 5 and 1 part of ALCH at 190 ° C. for 1 hour.

(Note) AF Solvent 5: Solvent manufactured by Nippon Petrochemical Co., Ltd.
ALCH: Kawaken Fine Chemical Co., Ltd. gelling agent

Preparation of inks Varnish Comparative Examples AE and Phthalocyanine Blue (Toyo Ink Manufacturing Co., Ltd. LIONOL BLUE FG7330) were mixed in the formulation shown in Table 2 (the amount of each component is shown in parts, the same applies hereinafter), and dispersed particles Each ink base was obtained by kneading with three rolls until it became 7.5 microns or less with a system measuring machine (grind meter). Next, for each ink base, soybean oil, compound, metal dryer, and drying inhibitor were added and stirred in the formulation shown in Table 2, and dimethylpolysiloxane, methylphenylpolysiloxane, and amino-modified silicone oil were added for the formulation shown in Table 2. Addition and stirring were performed to obtain Example 1-5 and Comparative Example 1-4.

Ink evaluation Table 3 shows the results of evaluating the viscosity, drying on paper, blocking, friction resistance, and gloss of the inks of Examples and Comparative Examples.

  The viscosity was measured with a cone plate viscometer.

  For the on-paper drying test, a color-printed print was prepared with a RI tester 6-segment roll and 0.1 ml of ink, and measured with a Chaoyang drying tester in a 25 ° C environment.

For blocking, create a color-print with a RI tester split roll, 0.125 ml of ink, overlap the ink-colored surfaces, leave it for 24 hours in a load of 100 g / cm ² and 50 ° C, 80% RH, It peeled off and confirmed visually.
Evaluation 3: No blocking.
2: Slightly blocking.
1: Completely blocking.

For friction resistance, create a color-print with a RI tester 2-split roll and 0.125 ml of ink pile, and apply ink to the backing paper with a load of 100 g / cm ² and reciprocating 10 times with a Gakushin type friction resistance tester. Visual evaluation of condition.
Evaluation 3: Almost no adhesion to the backing paper.
2: Slightly adhered to the backing paper.
1: A lot of sticking paper.

    For gloss, a color print was created with a RI tester split roll, 0.125 ml of ink, and the 60 ° -60 ° reflection gloss was measured with a gloss meter (Murakami Color Research Laboratory's digital gloss meter). The higher the value, the higher the gloss.

Claims (5)

A lithographic printing ink characterized in that the content of petroleum solvent in the ink is less than 15% by weight and 0.01 to 5% by weight of organopolysiloxane. 2. An ink for lithographic printing, wherein the organopolysiloxane according to claim 1 is amino-modified. The lithographic printing ink according to claim 1 or 2, wherein the ink contains 20% by weight or more of a vegetable oil or a vegetable oil-derived solvent. The lithographic printing ink according to any one of claims 1 to 3, wherein the aromatic component of the ink solvent is less than 1% by weight in the ink. A printed matter obtained by printing the lithographic printing ink according to claim 1.