JP2012046586A - Lithographic printing ink composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lithographic printing ink composition used for lithographic printing, especially to provide an environment-conscious ink for water-less printing in which the content of a volatile organic compound is reduced by making a vegetable oil be a principal component of a solvent component, and which does not discharge dampening water, and further to provide an ink which can strike a balance between scumming resistance and ink wearing property, which are the subject of water-less printing.SOLUTION: The lithographic printing ink composition includes a binder resin, vegetable oils, a paraffinic stock, and a pigment, wherein the rosin-modified phenol resin which has the softening point, the weight-average molecular weight, and the solubility of a fixed range and the paraffinic stock which has the boiling point of a fixed range are used, whereby a water-less ink can be obtained which has good scumming fitness and in which there is little of a volatile organic compound component.

Description

  The present invention relates to a lithographic printing ink composition (hereinafter abbreviated as “ink”) used for lithographic printing for printing books, flyers, catalogs, posters, etc., and in particular, vegetable oil is the main component of the solvent component. It is related to environmentally friendly ink for waterless printing that reduces the content of volatile organic compounds and does not discharge dampening water. And an ink that can achieve both the inking property.

  The waterless printing method in offset printing does not require fountain solution and does not require waste liquid treatment, and is therefore a printing method with less environmental impact. In waterless printing, a silicon rubber layer is used as a dampening water for watery printing, and an image can be formed by repelling ink. Since dampening water is not used as printability, temperature control of the printing press is important. If the roller temperature of the printing press is high, scumming may be induced. In order to avoid scumming, it is common to increase the elasticity of the ink, but if the elasticity of the ink is high, the inking property will deteriorate, so there is no water to achieve both scumming resistance and inking property. It is important for ink design.

  For waterless printing background stains, the theory that the solvent in the ink elutes on the silicone rubber layer surface and the solvent forms a layer to prevent the ink from adhering to the non-image area (WFBL theory) is prominent. It is. The solvent components used in low-volatile inks are mainly vegetable oils and vegetable oil esters, but these solvent components have good compatibility with rosin-modified phenolic resins used as ink binder components, so silicone rubber layers The problem is that waterless inks, which are difficult to elute on the surface and mainly contain vegetable oils as solvent components, have poor background stain resistance.

  Patent Document 1 and Patent Document 2 include a rosin-modified phenolic resin and a vegetable ester as solvent main components, a volatile organic compound component greatly reduced as compared with conventional inks, and a high-speed setting property. However, it is impossible to obtain the same level of stain resistance as that of a conventional waterless ink using a high-boiling petroleum solvent and vegetable oil or vegetable oil ester in combination.

JP 2002-69354 A JP 2002-155227 A

  The present invention has been made in order to solve such problems in the prior art, and the problem is that it can be used for waterless printing with a low environmental load, and the volatile organic compound component is The present invention provides an ink that is less liable to print and has good stain resistance.

  As a result of investigations aimed at solving the current problems, the present inventors, as a result, in a lithographic printing ink composition containing a binder resin, a vegetable oil, a paraffinic raw material oil, and a pigment, a specific softening point, weight average By using a rosin-modified phenolic resin having a molecular weight and solubility and a paraffinic raw material oil having a certain boiling point range, inventing a waterless ink having good scumming suitability and low volatile organic compound components. It came to.

That is, the present invention relates to a lithographic printing ink composition containing a binder resin, a vegetable oil, a paraffinic raw material oil, and a pigment.
Binder resin
Softening point 160-200 ° C,
Weight average molecular weight 50000-200000
and
Normal paraffin cloudiness temperature of 110-180 ° C
And the paraffinic feedstock
Boiling range 280-700 ° C
The present invention relates to a lithographic printing ink composition.

  Furthermore, the present invention relates to the lithographic printing ink composition according to claim 1, wherein the vegetable oil is 20 to 50% by weight in the total ink composition.

  The present invention also relates to the lithographic printing ink composition according to claim 1 or 2, wherein the paraffinic feedstock is 10 to 20% by weight in the total ink composition.

Furthermore, the present invention relates to a lithographic printing ink composition according to any one of claims 1 to 3, wherein the vegetable oil contains a fatty acid ester of vegetable oil.
Moreover, this invention relates to the printed matter formed by printing said lithographic printing ink composition on a base material.

  Conventionally, when an ink mainly composed of vegetable oil or the like as a solvent component is used in waterless printing, the solvent elution effect in the WFBL theory is limited, and the background stain resistance is inferior. If the viscosity of the ink is increased in order to improve the stain resistance in waterless ink mainly composed of vegetable oil, the tack will increase following the result, resulting in poor inking properties. According to the present invention, it is possible to provide a waterless ink with a small amount of volatile organic compounds, good scumming resistance, and good inking properties, which can contribute to the promotion of a reduction in environmental load.

  The softening point of the rosin-modified phenolic resin relating to the present invention is preferably in the range of 160 to 200 ° C, more preferably in the range of 165 to 195 ° C. If the temperature is lower than 160 ° C., elasticity suitable for waterless ink cannot be imparted, and if the softening point exceeds 200 ° C., the process of dissolving the resin to form a varnish becomes difficult.

  The weight average molecular weight of the rosin-modified phenolic resin relating to the present invention is preferably in the range of 50,000 to 200,000, more preferably in the range of 80000 to 170000. If it is less than 50000, the stain resistance suitable for waterless ink cannot be imparted, and if it exceeds 200,000, the step of dissolving the resin to form a varnish becomes difficult.

  The normal paraffin turbidity temperature of the rosin-modified phenolic resin relating to the present invention is preferably in the range of 110 to 180 ° C, more preferably in the range of 130 to 170 ° C. In the present invention, the normal paraffin white turbidity temperature refers to the lower limit temperature at which white turbidity occurs when 10% by weight of resin and 90% by weight of normal paraffin having 14 to 16 carbon atoms are heated and mixed. Is not observed.) If the temperature is less than 110 ° C., the solubility of the resin is too high, and thus the tackiness of the ink is high. If the clouding temperature exceeds 180 ° C., the solubility of the resin is too low, so that the solvent is easily removed and the ink is easily tightened on the machine.

  The boiling range of the paraffinic feedstock relating to the present invention is preferably in the range of 280 to 700 ° C, more preferably in the range of 315 to 550 ° C. If it is less than 280 ° C, it tends to volatilize and is not preferable from the viewpoint of environmental harmony. If the boiling point exceeds 700 ° C, the viscosity of the solvent is high and it is difficult to spread on the non-image area of the waterless plate surface. To do.

  The vegetable oils relating to the present invention are desirably contained in the total ink composition in an amount of 20 to 50% by weight, and more preferably in the range of 30 to 45% by weight. If it is less than 20% by weight, the weight ratio of the paraffinic raw material oil becomes high and it becomes difficult to dissolve the resin. If the weight ratio exceeds 50% by weight, there is no room for adding the paraffinic raw material oil.

  The paraffinic feedstock relating to the present invention is desirably contained in the total ink composition in an amount of 10 to 20% by weight, more preferably in the range of 12 to 18% by weight. If it is less than 10% by weight, there is little oozing out to the non-image area of the printing plate, and sufficient stain resistance cannot be ensured. If the weight ratio exceeds 20% by weight, it becomes difficult to dissolve the resin.

  It is preferable to contain a fatty acid ester as the vegetable oil relating to the present invention. When not contained, it becomes difficult to dissolve a resin having a high weight average molecular weight.

  The printing ink composition of the present invention can be produced by a conventionally known method. As an example, a binder resin, a vegetable oil component, a paraffinic raw material oil, and a gelling agent as necessary are added, and a varnish is produced under cooking conditions of 190 ° C. for 1 hour. Next, for example, a base for printing ink can be obtained by adding a pigment, a paraffinic raw material oil, a vegetable oil, a pigment dispersant or a pigment dispersion resin to the varnish and dispersing it with a bead mill or three rolls. Subsequently, vegetable oils, paraffinic raw material oils, and other additives are added to adjust to a predetermined viscosity to obtain a printing ink composition. The main types of ink are offset rotary printing press ink and sheet-fed printing press ink, but are not limited thereto.

  Examples of the pigment used in the present invention include general inorganic pigments and organic pigments. Examples of inorganic pigments include yellow lead, zinc yellow, bitumen, barium sulfate, cadmium red, titanium oxide, zinc white, dial, alumina white, calcium carbonate, ultramarine, carbon black, graphite, and aluminum powder. Organic pigments include azo pigments, soluble azo pigments such as C-based (β-naphthol-based), 2B-based and 6B-based (β-oxynaphthoic), β-naphthol-based, β-oxynaphthoic acid anilide-based, monoazo yellow-based, disazo Insoluble azo pigments such as yellow and pyrazolone, condensed azo pigments such as acetoacetate allylide, phthalocyanine, copper phthalocyanine (α blue, β blue, ε blue), halogenated copper phthalocyanine such as chlorine and bromine, metal Examples of free phthalocyanine pigments and polycyclic pigments include perylene, perinone, quinacridone, thioindigo, dioxazine, isoindolinone, and quinophthalone pigments. The addition amount of the pigment is 5 to 30% by weight with respect to the total amount of the printing ink composition.

  The binder resin used in the present invention includes rosin-modified phenol resin, rosin-modified maleic acid resin, alkyd resin, polyester resin, petroleum resin and the like, and these can be used alone or in combination of two or more.

  As the binder resin used in the present invention, it is possible to use a vegetable oil and / or a paraffinic raw material oil and a gelling agent such as an aluminum chelate compound, which is melted at 190 ° C. or more and varnished. Although possible, a gelling agent is not essential. The addition amount of the binder resin is 20 to 40% by weight with respect to the total amount of the printing ink composition.

  The vegetable oils in the present invention are vegetable oils and compounds derived from vegetable oils. Among the triglycerides of glycerin and fatty acids, at least one fatty acid is a fatty acid having at least one carbon-carbon unsaturated bond, and those triglycerides. Examples include fatty acid monoesters obtained by ester reaction with saturated or unsaturated alcohols, or fatty acid monoesters obtained by direct ester reaction between fatty acids of vegetable oil and monoalcohols, and ethers.

  Typical vegetable oils are: Asa seed oil, flaxseed oil, eno oil, psyllium oil, olive oil, cacao oil, kapok oil, kaya oil, mustard oil, kyounin oil, kiri oil, kukui oil, walnut oil, poppy oil, sesame oil , Safflower oil, radish seed oil, soybean oil, daikon oil, camellia oil, corn oil, rapeseed oil, niger oil, nuka oil, palm oil, castor oil, sunflower oil, grape seed oil, gentian oil, pine seed oil Cottonseed oil, palm oil, peanut oil, dehydrated castor oil, and the like.

  The fatty acid monoester is a fatty acid monoester obtained by transesterification of the above vegetable oil and monoalcohol or a direct ester reaction between the fatty acid of the vegetable oil and monoalcohol. Typical examples of monoalcohol include saturated alcohols such as methanol, ethanol, n- or iso-propanol, n, sec or t-butanol, heptynol, 2-ethylhexanol, hexanol, octanol, decanol, dodecanol, and oleyl alcohol. , Unsaturated fatty alcohols such as dodecenol, huseteri alcohol, somaryl alcohol, gadrelyl alcohol, 11-icosenol, 11-docosenol, 15-tetracosenol.

  Representative examples of ethers include di-n-octyl ether, dinonyl ether, diheptyl ether, dihexyl ether, didecyl ether, nonyl hexyl ether, nonyl heptyl ether, nonyl octyl ether and the like.

  The paraffinic raw material oil used in the present invention is a crude oil-derived solvent having an aromatic hydrocarbon content of 1% by weight or less, and has a use as a lubricating oil for industrial use.

  In addition, various additives for anti-friction, anti-blocking, slip and anti-scratch can be used as other additives in the lithographic printing ink composition. Leveling agents and antistatic agents can be used as necessary. An agent, a surfactant, an antifoaming agent, etc. may be added.

As an example of the composition of the lithographic printing ink composition of the present invention,
・ Binder resin 20-40% by weight
・ Vegetable oils 20-60% by weight
・ 1 to 10% by weight of fatty acid ester of vegetable oil
・ 10-20% by weight of paraffinic feedstock
・ Pigment 5-30% by weight ・ Other additives 1-5% by weight
Etc. are mentioned as preferred compositions.
Examples of the substrate used in the present invention include general printing paper such as coated paper and non-coated paper.

  The present invention will be described in more detail with reference to the following examples. However, the following examples do not limit the scope of rights of the present invention. In the present invention, “part” represents “part by weight” and “%” represents “% by weight”.

(Rosin modified phenolic resin production example)
In a reaction vessel, 1500 parts of gum rosin was reacted in advance with 850 parts of tertiary butylphenol and 260 parts of 92% by weight paraformaldehyde in a xylene solvent at 100 ° C. for 4 hours under a sodium hydroxide catalyst. The solution was dropped at 0 ° C. and reacted for 2 hours. Further, 150 parts of glycerin was added and reacted at 250 ° C. for 15 hours using 1.5 parts of calcium oxide as a catalyst. In the meantime, the resin was obtained as shown in Table 1 by taking out sequentially.

(Rosin modified phenolic resin varnish production example)
A stirrer, a reflux condenser with a water separator, and a four-neck flask with a thermometer, 45 parts of the rosin-modified phenolic resin (A to G) as a binder resin, 30 parts of soybean oil, 5 parts of normal butyl ester of soybean oil fatty acid The rosin-modified phenolic resin varnishes A to G were obtained by heating and stirring 20 parts of paraffinic raw material oil (Super Oil N56 manufactured by JX Nippon Oil & Energy Corporation, boiling range 345 to 520 ° C.) at 190 ° C. for 1 hour.

  Stirrer, reflux condenser with water separator, 4 neck flask with thermometer, 45 parts of rosin modified phenolic resin (B), 35 parts of soybean oil, 20 parts of paraffinic feedstock (JX Energy Oil Super Oil N56) was heated and stirred at 190 ° C. for 1 hour to obtain a rosin-modified phenolic resin varnish H.

  Stirrer, reflux condenser with water separator, 4-neck flask with thermometer, 45 parts of rosin modified phenolic resin (B) as binder resin, 30 parts of soybean oil, 5 parts of normal butyl ester of soybean oil fatty acid, paraffin A rosin-modified phenolic resin varnish I was obtained by heating and stirring 20 parts of a base material oil (Super Oil N22 manufactured by JX Nippon Oil & Energy Corporation, boiling range 265 to 450 ° C.) at 190 ° C. for 1 hour.

(Lithographic printing ink composition Example 1)
The composition of lithographic printing ink composition using rosin-modified phenolic resin varnish, carbon black (MA77 manufactured by Mitsubishi Chemical Corporation), soybean oil, and normal butyl ester of soybean oil fatty acid using three rolls in accordance with conventional methods. Examples and comparative examples were obtained. The lower part of Table 2 describes the amount of soybean oil, paraffinic raw material oil, and vegetable oil ester in the lithographic printing ink composition.

(Performance evaluation test (1) Soil evaluation test)
The background stain evaluation test was carried out on a sheet-fed printing press Lithlon 26 manufactured by Komori Corporation under the general printing pattern and density under the following printing conditions. A relative evaluation was performed.
CTP version: TAC-VG5 manufactured by Toray Industries, Inc.
Paper: OK Co., Ltd. OK Coat Printing speed: 10,000 sheets / hour Chiller setting temperature: 28 ° C

(Performance evaluation test (2) Evaluation of inking properties)
The printed matter obtained in the background stain test was visually evaluated in five stages as shown in Table 4.

(Performance evaluation test (3) Evaluation of volatility)
If the thermal weight loss in the VOC measurement method Method 24 (110 ° C., heating residue measurement by heating for 1 hour) presented by the US Environmental Protection Agency is less than 1%, it is evaluated as ◯.

  The performance evaluation test results are shown in Table 5.

  In Examples 1 to 4, both the background stain and the inking property are good, and the volatilization of the organic compound is extremely small. In Comparative Examples 1 and 2 in which the weight average molecular weight and softening point of the rosin-modified phenol resin are low, soiling is seen, so that it is difficult to put it into practical use. Comparative Example 3 having a high weight average molecular weight and softening point of the rosin-modified phenolic resin is not desirable from the viewpoint of printing quality because of poor inking properties. In Comparative Example 4 in which the amount of vegetable oil is small and the amount of paraffinic raw material oil is large, the resin is not sufficiently dissolved, and the inking property is poor. Also in Comparative Example 5 which does not contain an ester of vegetable oil fatty acid, since the resin is not sufficiently dissolved, the inking property is inferior. Example 6 using a paraffinic raw material oil that is easily volatilized is not preferable from the viewpoint of reducing the burden on the working environment and the global environment because it has a good soil contamination and a good inking property but has many volatile organic compound components.

Claims (5)

In a lithographic printing ink composition containing a binder resin, a vegetable oil, a paraffinic raw material oil and a pigment,
Binder resin
Softening point 160-200 ° C,
Weight average molecular weight 50000-200000
and
Normal paraffin cloudiness temperature of 110-180 ° C
And the paraffinic feedstock
Boiling range 280-700 ° C
A lithographic printing ink composition characterized in that:   2. The lithographic printing ink composition according to claim 1, wherein the vegetable oil is 20 to 50% by weight in the total ink composition.   The lithographic printing ink composition according to claim 1 or 2, wherein the paraffinic raw material oil is 10 to 20% by weight in the total ink composition.   The lithographic printing ink composition according to any one of claims 1 to 3, wherein the vegetable oil contains a fatty acid ester of vegetable oil.   A printed matter obtained by printing the lithographic printing ink composition according to any one of claims 1 to 4 on a substrate.