JPS62265374A - Dry lithographic ink composition - Google Patents

Abstract

PURPOSE:To provide the title compsn. having excellent printability and resistance to scumming, by reacting a petroleum resin with a specified chain extender in a hydrocarbon solvent and/or (semi)drying oil. CONSTITUTION:A petroleum resin (A) (e.g., a cyclopentadiene petroleum resin) produced by using, as a starting material, a fraction having a b.p. of 20-300 deg.C obtd. from the cracking or reforming of petroleum is reacted with at least one chain extender (B) selected from the group consisting of 2-20C polycarboxylic acids (derivatives) (e.g., maleic anhydride), pref. di- to tetrahydric alcohols (e.g., trimethylolpropane) and resol type phenolic resins (e.g., a p- aminophenol/formaldehyde precondensate) in a hydrocarbon solvent (C) having a b.p. of not lower than 150 deg.C (e.g., petroleum solvent having a b.p. of 200-350 deg.C) and/or (semi)drying oil (C) (e.g., linseed oil) at 100-350 deg.C for 0.1-10hr to obtain the title compsn. contg. a modified resin having a weight- average MW of not lower than 40,000 (in terms of PS).

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an ink composition for waterless lithographic printing that has good background stain resistance and excellent printability.

[Prior art]

In contrast to the current mainstream printing method, which uses the ink repellency of dampening water, a waterless planographic printing method was proposed that uses a planographic printing method that does not require dampening water.
In particular, a method of printing using a lithographic printing plate having silicone rubber in the non-image area has been put into practical use.

It is known that when conventional oil-based ink is used in such waterless planographic printing, scumming occurs, which is undesirable.

The phenomenon of scumming in waterless planographic printing is caused by the friction of the printing press's drive unit and rollers during printing, which causes the temperature of the plate surface to rise and the cohesive force of the ink itself to decrease, which is due to the fact that the ink itself is not naturally repellent. Ink adheres to non-print areas where it should be.

Such rings do not need to be considered at all in conventional lithographic printing using dampening water, and are a problem unique to waterless lithographic printing plates. This is because in the case of conventional planographic printing that uses dampening water, the ink repellent grooves are completely different.
In addition, since the increase in plate surface temperature is considerably suppressed by the evaporation of the dampening water, there is no need to consider such background smudge development, and it is said that it is preferable for the ink to have a small cohesive force.

In order to improve this problem, it is possible to consider a method of increasing the molecular weight of the binder resin component to increase the cohesive force and improve the dirt resistance. However, even if the resin component in an oil-based ink is made to have a high molecular weight by a conventional method, it is difficult to obtain a waterless lithographic ink that has good background stain resistance, excellent printability, and provides good printed matter.

[Problem that the invention seeks to solve]

The present invention was devised in view of the various drawbacks of the prior art, and its purpose is to provide an ink composition for waterless lithographic printing that has excellent background stain resistance and printability.

(Means for Solving the Problems) The object of the present invention is to dissolve in a hydrocarbon solvent with a boiling point of 150° C. or higher, in a drying oil or a semi-drying oil, or in a mixture thereof under heating and stirring. , obtained by elongating the molecular chain of a petroleum resin with a polyhydric carboxylic acid or its derivative, a polyhydric alcohol, a resol type phenolic resin, or a mixture thereof, with a weight average molecular weight of 4 based on polystyrene.
This is achieved by an ink composition for waterless lithographic printing which is characterized by containing 10,000 or more modified resins.

As the hydrocarbon solvent with a boiling point of 150°C or more used in the present invention, aliphatic, alicyclic, and aromatic hydrocarbons having 8 or more carbon atoms can be widely used, but it is preferably used as a normal oil-based ink solvent. Boiling point 200-350
C. right-handed solvents, such as high boiling point petroleum solvents such as paraffinic, isoparaffinic, α-olefinic, naphthenic, and aromatic-containing paraffinic solvents.

In the present invention, as the drying oil, animal and vegetable oils having an iodine value of 130 or more can be used, such as linseed oil, staghorn oil,
Eno oil, tung oil, dehydrated castor oil, etc., and their polymers are mentioned, and semi-drying oils include iodine value of 100 to 100.
130 animal and vegetable oils, such as cottonseed oil, soybean oil, sesame oil,
Examples include rapeseed oil and polymers thereof.

Here, petroleum resin is a resin produced by a known method using a secret compound with a boiling point of 20 to 300°C obtained during decomposition or reformation of petroleum as a starting material component, but preferably cyclopentadiene, Polymers of cyclopentadiene compounds such as methylcyclopentadiene and oligomers thereof, or copolymers of cyclopentadiene compounds with monoolefins, conjugated dienes, vinyl monomers, and unsaturated higher fatty acid esters. α the union.

Those modified by known methods with β-unsaturated dicarboxylic acids or their derivatives and/or polyhydric alcohols, resol-type p-alkylphenol/formaldehyde initial condensates, higher fatty acid esters having co-1Ω double bonds, etc. are used. Ru.

Further, in the present invention, examples of the polyhydric carboxylic acid or its derivative used as a molecular chain extender include polyhydric carboxylic acids having 2 to 20 carbon atoms, anhydrides, and monoesters thereof. The polyhydric carboxylic acid is usually 2
Preferred are carboxylic acids having a valence to 4, anhydrides thereof, and monoester compounds. Specifically, adipic acid, (anhydrous) succinic acid, (anhydrous) hexahydrophthalic acid, (anhydrous) phthalic acid, dimic acid, sepacic acid, etc. are particularly preferred, but maleic acid (anhydrous), ( anhydride) α, β- of citraconic acid, fumaric acid, maleic acid monoalkyl ester, etc.
Unsaturated dicarboxylic acids and their derivatives are used. Here, (anhydrous) means that the acid itself or an acid anhydride may be used.

The polyhydric alcohol is not particularly limited, but di- to tetrahydric polyhydric alcohols are usually preferred. Specifically, ethylene glycol, propylene glycol,
2 or more carbon atoms such as butylene glycol, diethylene glycol, dipropylene glycol, hexanediol, hexanetriol, trimedyllolpropane, glycerin, pentaerythritol, dipentaerythritol, etc.
15 is preferably used.

As resol type phenolic resins, for example, phenols such as phenol, cresol, balata-jalibderphenol, balaroctylphenol, balanonylphenol, balaphenylphenol, bisphenol A1 para-aminophenol are treated with formaldehyde in the presence of an alkali catalyst by a known method. It is obtained by reacting.

The modified resin of the present invention is prepared by dissolving a petroleum resin and a polycarboxylic acid or a derivative thereof under heating and stirring in a hydrocarbon solvent having a boiling point of 150° C. or higher, in a drying oil or a semi-drying oil, or in a mixture thereof. Alternatively, it can be obtained by reacting a polyhydric alcohol, a resol-type phenolic resin, or a mixture thereof, but the reaction conditions are usually in the range of 100 to 350°C, more preferably in the range of 150 to 270°C. The concentration of the reactant is usually 5 to 90% by weight. This reaction can be carried out in the manufacturing process of the varnish composition for printing ink. First, the resin component is dissolved in the solvent component by heating, and then at a predetermined temperature,
Although the molecular chain extender component is added and reacted, the order of addition may be changed. In addition, these reaction systems may contain components such as polar solvents or hydrocarbon solvents as components of the ink varnish composition.
Other components can be contained as needed.

The reaction time can be arbitrarily selected depending on the required characteristics of the intended ink varnish composition, but is usually 0.1 to 1.
0 hours, preferably 0.5 to 6 hours.

Molecular extension reactions involving petroleum resins, polyhydric carboxylic acids or their derivatives, polyhydric alcohols, resol-type phenolic resins, or mixtures thereof are mainly esterification reactions, Ziels-Alder reactions, methylenation reactions, and chroman ring-forming reactions. If a drying oil or semi-drying oil component is present in the reaction system, a part of the drying oil or semi-drying component may be incorporated into the reaction system.

The present inventors conducted such a molecular chain elongation reaction in a hydrocarbon solvent having a boiling point of 150° C. or higher, in a drying oil or a semi-drying oil, or in a mixture thereof under heating and dissolving stirring. Polystyrene standard weight average molecular weight 4
It has been discovered that an ink composition containing 10,000 or more modified resin as a binder resin component can be used as an ink for waterless lithographic printing that has good stain resistance and excellent printability in waterless lithographic printing, and the present invention has been made based on the present invention. has been reached.

The molecular weight needs to be 40,000 or more in order to maintain excellent print finishing characteristics, the required characteristics of the ink, and to prevent background smearing.

The upper limit of the molecular weight is usually preferably 200,000 or less.

The composition containing the modified resin according to the present invention has conventionally been prepared by:
It is usually made into an ink by adding other known ink components used for lithographic printing.

Such components include, if necessary, additional resin components such as phenol resin, rosin-modified phenol resin, alkyd resin, rosin ester resin, petroleum resin,
There are maleic acid resins, drying oils, semi-drying oils, etc., and these may be simply added, or may be combined with the resin composition obtained in the present invention. As gelling agents, organic aluminum compounds, organic titanate compounds, organic zinc compounds, organic calcium compounds, etc.
If necessary, additional solvents with boiling points of 200 to 350
℃ petroleum solvents, etc.

In addition, as a coloring agent when used as an ink, those used in conventional ink compositions, such as inorganic or organic pigments, can be used.

Additionally, waxes, greases, desiccants, dispersants,
Fillers and other known materials can be used as necessary.

The ink kneaded with the Miki roll using the above-mentioned materials has a high scumming temperature, has excellent printability, and is a well-balanced ink for waterless lithographic printing.

In the present invention, the polystyrene standard weight average molecular weight is measured by gel permeation chromatography (GPC), and the measurement conditions are as follows.

(1) Measurement conditions A, equipment Nigel permeation chromatograph GPC-24
4 (to the buttocks TE10> B, data processing: TRC GPC data processing system C, column: TSK-GEL-GMH6 (2) Dj8 medium: tetrahydrofuran E, flow rate:
2ml/mln F, Temperature: 23°C G, Sample: Concentration: 0.2% (wt/vol) Solubility: Complete dissolution port: 0, 45! l-3hodexDTE[)
-13CIIH1 injection volume: 0.5ml ■, Detector: Differential refractive index detector, R-401 (WATER3) J6 molecular weight calibration: Polystyrene (Note>TRC: Abbreviation of Talk Research Center Co., Ltd. (ink characteristics and Printing characteristics evaluation method) A waterless lithographic plate with a non-adhesive layer made of silicone rubber was attached to a printing machine that had been modified so that the temperature of the plate surface could be raised by passing hot water through the plate cylinder, and the plate surface was heated without supplying dampening water. The surface temperature at which background smear occurs on printed matter at a constant solid density during printing while increasing the temperature was defined as the background smear generation temperature.Inks with a high background smudge generation temperature are less likely to cause background smear in practical printing. .

Next, the fluidity (flow value) of these inks was measured with a spread meter at 30°C, and the tack value was measured with an incometer. Each ink was printed using a waterless lithographic plate, and a Macbeth densitometer was used to measure the fluidity (flow value) of these inks. The gloss value of the printed matter at a solid density of 0.95 was measured using a 60 degree specular reflection gloss meter. [Example] The following is a detailed explanation using examples, but the present invention is not limited thereto. isn't it.

Note that the numbers used in Examples and Comparative Examples are parts by weight.

Example 1 Cyclopentadiene petroleum resin (polystyrene standard weight average molecular weight 360,000 max., softening point 160°C (JIS K-
2531 >> 40 parts, “Shinjuku Flax Pasta N, 4 (Toshin Yushi (
10 parts of drying oil made by Mitsubishi Chemical Industries, Ltd. 25 parts of "Diyaren 168" (hydrocarbon solvent for ink made by Mitsubishi Chemical Industries, Ltd.) were mixed under a nitrogen flow, heated to raise the temperature, and mixed with maleic anhydride while heating and stirring at 200°C. After adding 4 parts and then 1.5 parts of trimethylolpropane and heating and stirring at 200"C for 5 hours,
19.5 parts of "IP Solvent 2835" (hydrocarbon solvent for ink manufactured by Idemitsu Petrochemical Co., Ltd.) was added, and the mixture was heated and stirred at 150° C. for 30 minutes.

The polystyrene standard weight average molecular weight of the modified resin in the varnish thus obtained was determined to be 6.5 by GPC curve analysis.
It was measured at 10,000.

The cyclopentadiene-based petroleum resin used as the raw material resin in this example was obtained by polymerizing a mixture of cyclopentadiene and dicyclopentadiene by a known method, and had a softening point of 10.
It is a brownish-brown resin produced by modifying a yellowish-brown resin at 5°C with maleic anhydride, a resol-type p-aminephenol formaldehyde initial w1 condensate, and dehydrated castor oil.

Add 85 parts of the ink varnish coated in this way to “Seiriki First” Yellow 2340 (Dainichiseika Co., Ltd.)
15 parts of pigment for ink was added and kneaded using three rolls in a conventional manner to obtain ink A@.

Example 2 In Example 1, 1.5 parts of trimethylolpropane was not used, and the amount of "IP Solvent 2835" was changed to 21 parts.
A varnish was produced in the same manner by changing the part. The polystyrene 1)Q weight average molecular weight of the modified resin in the varnish thus obtained was determined to be 5.61 million by GPC curve analysis.

From the ink varnish thus obtained, Example 1
Ink B was obtained in the same manner.

Example 3 In Example 2, 2 parts of trimethylolpropane was used instead of maleic anhydride and "IP Solvent 28
Ink C was obtained by changing the amount of 35'' used to 23 parts and making it into varnish and ink in the same manner.

Comparative Example 1 Ink D was obtained by changing the amount of "IP Solvent 2835" used in Example to 25 parts and performing varnish and ink production in the same manner without using maleic anhydride and trimethylolpropane. .

Comparative Example 2 Ink E was prepared by changing the amount of petroleum resin used in Example 1 to 43 parts, and making varnish and ink in the same manner without using maleic anhydride and trimethylolpropane.
I got it.

Ink A- obtained in each of the above-mentioned Examples and Comparative Examples
E was evaluated for ink characteristics and printing characteristics, and the results are shown in Table 1.

From this result, it can be seen that inks A, B, and C that satisfy the present invention have a higher scumming temperature and a relatively better tack value than blank inks D and E.

In a practical printing test, inks A, B, and C were compared with inks D and E, and inks A1B and C were both less likely to stain the paper surface, and also suppressed printing problems such as piling and paper peeling. It had become something like that.

Example 4 “IP Solvent 2835” 10 parts, “Dialen 16”
8” 10 parts, petroleum resin 37 parts, “Marine pure flax” N, 410
To this, 3 parts of resol type phenol resin was added and reacted at 195°C for 3 hours while heating and stirring to dissolve 1 part of the resin.
An ink varnish was prepared by adding and diluting 15 parts of "Dialen 168" and 15 parts of "Dialen 168".

The petroleum resin used here as a raw material component is a yellowish brown resin with a softening point of 125°C obtained by polymerizing a mixture of cyclopentadiene and dicyclopentadiene by a known method, maleic anhydride and resol type p-tert-butylphenol.・Formaldehyde initial condensate, softening point obtained by modifying with dehydrated castor oil, 155°C! Value 22 mqKOH/g
, Po'J Steel L/N W is a brownish brown resin with a 4 weight average molecular weight of 6.5 million.

In addition, resol type phenolic resin is p-
It is obtained by initial condensation of amylphenol and formaldehyde using a known method.

The varnish thus obtained was converted into an ink in the same manner as in Example 1 to obtain Ink F.

The scumming temperature of this ink F is 33°C1 tack value 1
1.5, the flow value was 39.5 mm, and even in practical printing at an air temperature of 25° C., no staining occurred on the paper surface of the printed matter.

Comparative Example 3 When 37 parts of the petroleum resin used in Example 4 and 3 parts of resol-type phenolic resin were mixed and heated to 195°C without using a solvent, drying oil, or semi-solid oil, no insoluble or insoluble It became a melting resin.

Example 5 40 parts of the cyclopentanediene petroleum resin used in Example 1 and 30 parts of "Dialene 168" were mixed and heated to 185°C with stirring, and 3 parts of maleic anhydride was added. The mixture was then heated and stirred at the same temperature for 4 hours. Next, 412 parts of pure marine flax and 15 parts of IP Solvent Kettle 835 were added, and the mixture was heated and stirred at 145°C for 15 minutes.

The weight average molecular sphere of the modified resin in the varnish thus obtained was 5.7 times the polystyrene standard. Ink H was obtained from the varnish thus obtained in the same manner as in Example 1.

The scumming temperature of this ink H is 32°C, tack 1
21, the flow value was 38.5 mm, and the practical printing results at room temperature of 25°C were also good.

Example 6 40 parts of the cyclopentadiene petroleum resin used in Example 1 and 415 parts of "marine pure flax" N were mixed and heated at 185°C under a stream of nitrogen, and mixed with maleic anhydride while stirring. 4 parts were added, and the mixture was heated and stirred at the same temperature for 3 hours.Next, 20 parts of "Dialen 168" and "IP Solvent 283" were added.
5" was added thereto, and the mixture was heated and stirred at 145°C for 15 minutes.

The polystyrene standard weight average molecular weight of the modified resin in the varnish thus obtained was 62,000. Ink (2) was obtained from the varnish thus obtained in the same manner as in Example 1.

The scumming temperature of this ink I is 33℃, and the tack value is 11.
．． 8. The flow value was 34.1n++n, and the practical printing results at an air temperature of 25°C were also good.

〔Effect of the invention〕

The ink composition for waterless lithography containing a specific modified resin as a binder resin component according to the present invention has particularly good stain resistance and excellent printability.

Claims (1)

[Claims] Petroleum resins are dissolved under heating and stirring in a hydrocarbon solvent with a boiling point of 150°C or higher, in drying oil or semi-drying oil, or in a mixture thereof. An ink composition for waterless lithographic printing, comprising a modified resin having a weight average molecular weight of 40,000 or more based on polystyrene, which is obtained by elongating the molecular chain with a resin or a mixture thereof.