JP2008255181A - Printing ink composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink suitable for printing requiring security of half-tone dot quality irrespective of paper having particularly low paper surface strength in relation to a printing ink composition used for offset printing for printing books, leaflets, catalogs etc. <P>SOLUTION: The offset printing ink composition comprises 3-30 wt.% of a rosin-modified phenol resin (a) having ≥150,000 weight-average molecular weight and 3-45 wt.% of at least one kind selected from (b) and (c). (b) a petroleum-based solvent containing ≥90 wt.% of n-paraffins and (c) a polybutene and/or a polybutadiene having 1,000-5,000 number-average molecular weight. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a printing ink composition (hereinafter abbreviated as “ink”) used for offset printing for printing books, leaflets, catalogs, etc., and in particular, to ensure halftone dot quality even with paper having low paper surface strength. Therefore, the present invention provides an ink suitable for printing that is required for printing.

  In recent years, the number of copies of free paper provided free of charge on the streets and the like has increased, but in many cases, uncoated paper is used as paper. Non-coated paper generally has a low paper surface strength, and thus is liable to cause problems such as paper peeling and poor inking. In particular, in recent years, paper with a high ratio of used paper has increased in specific gravity in the market, and has been in a situation where paper peeling is likely to occur due to a shortened fiber length.

  When printing on non-coated paper, an ink having a low tack is generally used as a measure against paper peeling. However, since color photographs are frequently used for free paper, if ink with a low tack is simply used, halftone dots are crushed and dot gain is increased, and good image reproduction cannot be expected.

  The present invention has been made to solve such problems in the prior art, and the problem is that in offset printing using non-coated paper, no paper peeling occurs, and The present invention provides an ink having excellent dot quality.

  As a result of studying the present inventor with the aim of solving the current problems, the ink that maintains the viscosity value in the cone-plate viscometer while reducing the tack value significantly reduces paper peeling, and They found that they provide prints with small dot gain and excellent dot quality. It has been found that it is effective to blend specific materials effectively in order to ensure such ink properties.

1st invention contains 3 to 45 weight% of rosin modified phenolic resin (a) whose weight average molecular weight is 150,000 or more (a) 3 to 30 weight% and at least 1 sort (s) chosen from (b) and (c). It is the offset printing ink composition characterized.
(B) Petroleum solvent containing 90% by weight or more normal paraffin (c) Polybutene and / or polybutadiene having a number average molecular weight of 1000 to 5000 The second invention is the rosin-resole ratio of the rosin-modified phenol resin The offset printing ink composition according to the first invention, wherein the ratio is 60% or more and 70% or less.

A third invention is the offset printing ink composition according to the first or second invention, wherein the normal paraffin has 14 to 16 carbon atoms.
A fourth invention is a printed matter obtained by printing with the offset printing ink composition according to any one of the first to third inventions.
JP-A-6-172694

  In the past, the halftone quality of printed matter was not good because the paper peeling that was likely to occur on non-coated paper was suppressed simply by reducing the tack, but the present invention specified that the ink tackiness was low. By blending these materials, it is possible to obtain printed matter with small dot gain and excellent dot quality.

  The rosin-modified phenolic resin relating to the present invention is characterized by a higher weight average molecular weight than commonly used resins. The addition amount of the rosin-modified phenolic resin is desirably 3% by weight or more and 30% by weight or less, and preferably 5% by weight or more and 27% by weight. If the amount added is less than 3% by weight, a viscosity sufficient to suppress dot gain cannot be obtained. If the amount added exceeds 30% by weight, the elasticity of the ink becomes excessively high and fluidity is impaired. Smooth transferability between rollers cannot be secured.

  The rosin-modified phenolic resin is obtained by reacting rosin, which is a resin acid, resole, which is a condensate of alkylphenol and formalin, and a polyhydric alcohol, and a third component such as maleic acid may be added as necessary. is there. The blending ratio of rosin and resole is one of the important factors controlling the physical properties of the resin. The blending ratio of rosin in the rosin-modified phenolic resin according to the present invention is desirably 60% by weight or more and 70% by weight or less, and preferably 62% by weight or more and 67% by weight or less. If the ratio is less than 60% by weight, the resole has excessive alkyl groups. As a result, the solubility of the resin in the solvent becomes excessive, making it difficult to achieve the desired high viscosity of the ink. Since the alkyl group of the resole is reduced and the solubility of the resin in the solvent is too bad, the solvent may be separated from the ink.

  The solvent used in the offset ink is generally a high boiling point petroleum solvent having an aromatic component content of 1% by weight or less, and is called an aroma-free solvent. The main components are naphthene and paraffin, and the more naphthene component is common. The solvent relating to the present invention has a normal paraffin component content of 90% by weight or more, the addition amount is desirably 3% by weight or more and 45% by weight or less, preferably 5% by weight or more and 30% by weight or less, Preferably they are 7 weight% or more and 15 weight% or less. If the amount added is less than 3% by weight, the ink viscosity sufficient to improve the halftone dot quality of the printed matter cannot be imparted. If the amount added exceeds 45% by weight, the solubility in the resin is remarkably inferior. As a result of excessive removal of the solvent, the smoothness of the printed matter is impaired and the gloss may be lowered.

  The carbon number of the normal paraffin according to the present invention is preferably in the range of 14-16. If the number of carbon atoms is less than 14, the boiling point of the solvent becomes excessively low, evaporation of the solvent is promoted on the rollers of the printing press, and the tackiness of the ink increases. When the number of carbons exceeds 16, it becomes difficult to dry in the hot air drying step in offset rotary printing, which may cause poor drying.

  The polybutene and / or polybutadiene according to the present invention is preferably liquid at normal temperature, and the number average molecular weight is 1000 to 5000, preferably 25000 to 3500. If the number average molecular weight is less than 1000, the effect of increasing the viscosity of the ink cannot be expected, and if the number average molecular weight exceeds 5000, the fluidity of the ink is lowered and the paper is hardened.

  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, and a gelling agent as necessary are added to produce a varnish under cooking conditions of 190 ° C. for 1 hour. Next, for example, a base for printing ink can be obtained by adding a pigment, petroleum solvent, vegetable oil, pigment dispersant or pigment dispersion resin to the varnish and dispersing with a bead mill or three rolls. Subsequently, vegetable oils, petroleum-based solvents, and other additives are added to adjust the viscosity to a predetermined value 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, aluminum powder, and the like.
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), copper halide 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.

  Examples of the binder resin used in the present invention include rosin-modified phenol resins, petroleum resins, alkyd resins, rosin-modified alkyd resins, petroleum resin-modified alkyd resins, and rosin esters. The rosin-modified phenolic resin can control the ink properties by using both a resin having a constant rosin / resole ratio and a resin constant having a weight average molecular weight of 150,000 or more according to the present invention. The addition amount of the binder resin is 3 to 50% 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 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 related to the present invention 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, Examples include pine seed oil, cottonseed oil, coconut oil, peanut oil, and dehydrated castor oil. The thing which polymerized these vegetable oils is also mentioned. The amount of vegetable oil added is 1 to 40% by weight based on the total amount of the printing ink composition.

  Fatty acid monoesters are those obtained by transesterification of the above vegetable oil and monoalcohol, or fatty acid monoesters obtained by directly esterifying the fatty acid and monoalcohol of vegetable oil. 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, husetelli alcohol, somaryl alcohol, gadrelyl alcohol, 11-icosenol, 11-docosenol, and 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.

In addition to normal paraffin having 14 to 16 carbon atoms, the petroleum solvent related to the present invention may be used in combination with a petroleum solvent generally containing less than 1% by weight of aromatic hydrocarbons called an aroma-free solvent. I can do it. The initial boiling point of the aroma-free solvent is preferably 240 ° C or higher and 300 ° C or lower. At an initial boiling point below 240 ° C., the solvent is likely to evaporate on the rollers of the printing press, leading to an increase in tack. When the initial boiling point exceeds 300 ° C., it becomes difficult to dry in the hot air drying step in offset rotary printing, and there is a possibility of causing poor drying.
EXAMPLES 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 examples, “part” represents “part by weight”.

  (Rosin-modified phenol resin Example A) In a reaction vessel, 1500 parts of gum rosin was reacted in advance with 600 parts of paraoctylphenol and 210 parts of 92% by weight paraformaldehyde in a xylene solvent at 100 ° C. for 4 hours under a sodium hydroxide catalyst. The phenol resin from which moisture was removed was dropped at 150 ° C. and reacted for 2 hours. Further, 160 parts of pentaerythritol was added and reacted at 250 ° C. for 10 hours using 1.5 parts of zinc acetate as a catalyst to obtain rosin-modified phenol resin A having a weight average molecular weight of 162,000 (rosin / resole ratio = 64). / 36).

  (Rosin-modified phenol resin Example B) In a reaction vessel, 1500 parts of gum rosin was reacted in advance with 600 parts of t-butylphenol and 280 parts of 92% by weight paraformaldehyde in a xylene solvent at 100 ° C. for 4 hours under a sodium hydroxide catalyst. The phenol resin from which moisture was removed was dropped at 150 ° C. and reacted for 2 hours. Further, 160 parts of pentaerythritol was added and reacted at 250 ° C. for 10 hours using 1.5 parts of zinc acetate as a catalyst to obtain rosin-modified phenol resin B having a weight average molecular weight of 178000 (rosin / resole ratio = 65 / 35).

  (Rosin-modified phenol resin comparative example C) In a reaction vessel, 1500 parts of gum rosin was reacted in advance with 850 parts of nonylphenol and 260 parts of 92% by weight paraformaldehyde at 100 ° C. for 4 hours under a sodium hydroxide catalyst. The phenol resin from which water was removed was dropped at 150 ° C. and reacted for 2 hours. Further, 150 parts of glycerin was added and reacted at 250 ° C. for 10 hours using 1.5 parts of calcium oxide as a catalyst to obtain a rosin-modified phenol resin C having a weight average molecular weight of 105000 (rosin / resole ratio = 58 / 42).

  (Rosin-modified phenolic resin varnish example D) In a four-necked flask with a stirrer, water separator and thermometer, rosin-modified phenolic resin A43 parts, soybean oil 12 parts, petroleum solvent (new) 45 parts of Nippon Oil Co., Ltd. AF Solvent 7) was heated and stirred at 190 ° C. for 1 hour to obtain rosin-modified phenolic resin varnish D.

  (Rosin-modified phenolic resin varnish example E) In a four-necked flask with a stirrer, a water separator and a reflux condenser, and a thermometer, 42 parts of rosin-modified phenolic resin B, 12 parts of soybean oil, petroleum solvent (new 46 parts of Nippon Oil Co., Ltd. AF solvent 7) was heated and stirred at 190 ° C. for 1 hour to obtain rosin-modified phenolic resin varnish E.

  (Rosin-modified phenolic resin varnish comparative example F) In a four-necked flask with a stirrer, water separator and thermometer, rosin-modified phenolic resin C46 parts, soybean oil 12 parts, gelling agent (river) A rosin-modified phenolic resin varnish F was obtained by heating and stirring 1 part of ALCH manufactured by Ken Fine Chemical Co., Ltd. and 41 parts of petroleum solvent (AF Solvent 7 manufactured by Shin Nippon Oil Co., Ltd.) for 1 hour.

  (Printing Ink Composition Example 1) 59 parts of carbon black (MA77 manufactured by Mitsubishi Chemical Corporation) and 21 parts of petroleum solvent (AF Solvent 7 manufactured by Nippon Oil Corporation) were added to 59 parts of rosin-modified phenolic resin varnish D. In addition, an offset printing ink composition Example 1 was obtained using three rolls according to a conventional method.

  (Printing ink composition example 2) To 58 parts of rosin-modified phenolic resin varnish D, 20 parts of carbon black (MA77 manufactured by Mitsubishi Chemical Corporation), 12 parts of petroleum solvent (AF Solvent 7 manufactured by Nippon Oil Corporation), 10 parts of normal paraffin (Cactus normal paraffin SHNP manufactured by Japan Energy Co., Ltd.) was added, and an offset printing ink composition example 2 was obtained using three rolls according to a conventional method.

  (Printing Ink Composition Example 3) 56 parts of rosin modified phenolic resin varnish D, 20 parts of carbon black (MA77 manufactured by Mitsubishi Chemical Corporation), 12 parts of petroleum solvent (AF Solvent 7 manufactured by Nippon Oil Corporation), Add 10 parts of normal paraffin (Cactus normal paraffin SHNP manufactured by Japan Energy Co., Ltd.) and 2 parts of liquid polybutene (HV-1900 manufactured by Shin Nippon Petrochemical Co., Ltd., number average molecular weight 2900). Thus, an offset printing ink composition example 3 was obtained.

  (Printing Ink Composition Example 4) 56 parts of rosin-modified phenolic resin varnish D20, carbon black (MA77 manufactured by Mitsubishi Chemical Co., Ltd.), 12 parts petroleum solvent (AF Solvent 7 manufactured by Nippon Oil Corporation), Add 10 parts of normal paraffin (Cactus normal paraffin SHNP manufactured by Japan Energy Co., Ltd.) and 2 parts of liquid polybutadiene (Nisso PB B-3000 manufactured by Nippon Soda Co., Ltd., number average molecular weight 3000), and use a three roll according to a conventional method. Thus, an offset printing ink composition example 4 was obtained.

  (Printing ink composition Example 5) 20 parts of carbon black (MA77 manufactured by Mitsubishi Chemical Co., Ltd.) and 22 parts of petroleum solvent (AF Solvent 7 manufactured by Nippon Oil Corporation) were added to 58 parts of rosin-modified phenolic resin varnish E58. In addition, an offset printing ink composition Example 5 was obtained using three rolls according to a conventional method.

  (Printing Ink Composition Example 6) 57 parts of rosin-modified phenolic resin varnish E20, 20 parts of carbon black (MA77 manufactured by Mitsubishi Chemical Corporation), 13 parts of petroleum solvent (AF Solvent 7 manufactured by Nippon Oil Corporation), 10 parts of normal paraffin (Cactus normal paraffin SHNP manufactured by Japan Energy Co., Ltd.) was added, and an offset printing ink composition example 6 was obtained using three rolls according to a conventional method.

  (Printing Ink Composition Example 7) 55 parts of rosin-modified phenolic resin varnish E20, 20 parts of carbon black (MA77 manufactured by Mitsubishi Chemical Corporation), 13 parts of petroleum solvent (AF Solvent 7 manufactured by Nippon Oil Corporation), Add 10 parts of normal paraffin (Cactus normal paraffin SHNP manufactured by Japan Energy Co., Ltd.) and 2 parts of liquid polybutene (HV-1900 manufactured by Shin Nippon Petrochemical Co., Ltd., number average molecular weight 2900). Thus, an offset printing ink composition example 7 was obtained.

  (Printing ink composition example 8) 55 parts of rosin modified phenolic resin varnish E20, carbon black (MA77 manufactured by Mitsubishi Chemical Co., Ltd.), 13 parts petroleum solvent (AF solvent 7 manufactured by Nippon Oil Corporation), Add 10 parts of normal paraffin (Cactus normal paraffin SHNP manufactured by Japan Energy Co., Ltd.) and 2 parts of liquid polybutadiene (Nisso PB B-3000 manufactured by Nippon Soda Co., Ltd., number average molecular weight 3000), and use a three roll according to a conventional method. Thus, an offset printing ink composition example 8 was obtained.

  (Printing Ink Composition Example 9) Rosin-modified phenolic resin varnish E25 parts, rosin-modified phenolic resin varnish F34 parts, carbon black (MA77 manufactured by Mitsubishi Chemical Co., Ltd.) 20 parts, petroleum solvent (Shin Nippon Oil Co., Ltd.) 9 parts of AF solvent 7), 10 parts of normal paraffin (Cactus normal paraffin SHNP manufactured by Japan Energy Co., Ltd.), 2 parts of liquid polybutadiene (Nisso Soda Co., Ltd. NISSO PB B-3000, number average molecular weight 3000) are added. An offset printing ink composition Example 9 was obtained using three rolls according to a conventional method.

  (Printing ink composition example 10) 35 parts of rosin modified phenolic resin varnish E23, rosin modified phenolic resin varnish F23 part, carbon black (MA77 manufactured by Mitsubishi Chemical Corporation), petroleum solvent (Shin Nippon Oil Co., Ltd.) 10 parts of AF solvent 7), 10 parts of normal paraffin (Cactus normal paraffin SHNP manufactured by Japan Energy Co., Ltd.), 2 parts of liquid polybutadiene (Nisso Soda Co., Ltd. NISSO PB B-3000, number average molecular weight 3000) are added. An offset printing ink composition Example 10 was obtained using three rolls according to a conventional method.

  (Printing ink composition comparative example 1) 20 parts of carbon black (MA77 manufactured by Mitsubishi Chemical Corporation) and 20 parts of petroleum-based solvent (AF Solvent 7 manufactured by Nippon Oil Corporation) were added to 25 parts of rosin-modified phenolic resin varnish E. In addition, an offset printing ink composition comparative example 1 was obtained using three rolls according to a conventional method.

  (Printing ink composition comparative example 2) To rosin-modified phenolic resin varnish F60 part, carbon black (Mitsubishi Chemical Corporation MA77) 20 parts, petroleum solvent (Shin Nippon Oil Co., Ltd. AF solvent 7) 10 parts, 10 parts of normal paraffin (Cactus normal paraffin SHNP manufactured by Japan Energy Co., Ltd.) was added, and an offset printing ink composition comparative example 2 was obtained using three rolls according to a conventional method.

(Performance evaluation test 1 tack)
The tack of the printing ink compositions (Examples 1 to 10 and Comparative Examples 1 and 2) was measured with a Toyo Seiki Co., Ltd. incometer at a rotation speed of 400 rpm and 1200 rpm at 30 ° C. did.
(Performance evaluation test 2 Viscosity)

The viscosities of the printing ink compositions (Examples 1 to 10 and Comparative Examples 1 and 2) were measured at 25 ° C. with a cone and plate viscometer (HAKAKE PK-100).
(Performance evaluation test 3 Paper peeling resistance)
NEO800 manufactured by Mitsubishi Heavy Industries, Ltd. was used as an off-wheel printing machine, and printing was performed under conditions of a printing speed of 800 rpm and a paper surface temperature of 110 ° C. A special Marusumi paper product (813 × 1085) was used for the paper, and Akwa Unity WKK made by Toyo Ink Mfg. Co., Ltd. was used for the dampening water at a concentration of 2% by weight. About the solid part of the pattern, the degree of occurrence of paper peeling was judged visually, and it was described in five stages as shown in Table 2.

(Performance evaluation test 4 dot gain)
With respect to the dot gain measurement chart portion of the printed matter obtained by the above printing, the dot gain at a halftone dot of 50% when the solid density was 1.20 by a Gretag densitometer was measured.

  The performance evaluation test results are shown in Table 3. In Examples 1 to 10 and Comparative Examples 1 and 2, although the viscosities were approximate values, the tacks of Examples 1 to 10 were lower. It was confirmed that the use of normal paraffin in the solvent was more effective in lowering the tack, and that the use of polybutene or polybutadiene was more effective in lowering the tack. In Examples 1 to 10, the paper peeling is significantly reduced as compared with Comparative Examples 1 and 2, and the dot gain of a halftone dot can be suppressed.

Claims (4)

An offset printing ink comprising 3 to 30% by weight of rosin-modified phenolic resin (a) having a weight average molecular weight of 150,000 or more and 3 to 45% by weight of at least one selected from (b) and (c) Composition.
(B) A petroleum solvent containing 90% by weight or more normal paraffin (c) polybutene and / or polybutadiene having a number average molecular weight of 1000 to 5000   The offset printing ink composition according to claim 1, wherein the rosin ratio of the rosin-modified phenol resin is 60% or more and 70% or less.   The offset printing ink composition according to claim 1 or 2, wherein the normal paraffin has 14 to 16 carbon atoms. A printed matter obtained by printing with the offset printing ink composition according to any one of claims 1 to 3.