JP2010248286A - Printing ink composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink composition for offset sheet-fed printing which can reduce back cylinder print by an impression cylinder of an offset printing machine while maintaining friction resistance of the ink printed onto paper by selecting the type and adding amount of wax in an offset sheet-fed printing. <P>SOLUTION: The ink composition for offset sheet printing includes a wax, a binder resin, vegetable oils, a petroleum solvent, and a pigment, wherein the wax is a polytetrafluoroethylene wax having an average particle diameter of 3.5-4.5 μm, a melting point of 290-340°C, and sphericity of 0.2-0.7; and a polyethylene wax having an average particle diameter of 1.0-4.0 μm, a melting point of 100-200°C, and sphericity of 0.9-1.0. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to offset sheet-fed printing, and an offset sheet-fed printing ink composition that can reduce the impression of an ink offset printing press while maintaining the friction resistance of ink printed on paper. About.

  In an offset sheet-fed printing press, the ink once transferred to the paper surface may be turned over in a set and dried state on the paper surface, and printing may be performed on the back surface. (Set is a state where the solvent in the ink penetrates the paper and does not stick even when touched, and drying on the paper means that the vegetable oil in the ink is oxidatively polymerized and the ink is hardened after setting). When printing on the back surface, the front surface comes into contact with the impression cylinder while being pressed between the blanket cylinder and the impression cylinder, so that ink adheres to the impression cylinder. This phenomenon is referred to as impression cylinder removal.

  In general, polyethylene wax, polytetrafluoroethylene wax, polypropylene wax, paraffin wax, microcrystalline wax, carnauba wax, beeswax and the like are used as waxes in order to impart friction resistance to ink printed on paper. (Japanese Patent Laid-Open No. 2003-221536, Japanese Patent Laid-Open No. 2007-254629) This is because the wax dispersed in the ink protrudes on the surface of the ink after printing to reduce the contact area, or the wax itself spreads thinly, thereby reducing the surface of the ink. Because it protects.

  In conventional offset sheet-fed printing ink compositions, wax has been added to impart friction resistance to ink printed on paper, but on the other hand, ink that contains a large amount of wax that has been used in the past. The above-described impression cylinder is likely to be removed, and a printing pattern on the front surface is taken at the time of printing on the back side, and cleaning of the impression cylinder must be frequently performed, so that work efficiency is significantly reduced.

JP 2003-221536 A JP 2007-254629 A

Takahiro Tsunoda et al. "Basic Printing Technology" Sangyo Tosho Co., Ltd.

  The present invention solves the above-mentioned problems in offset sheet-fed printing, and can reduce impression cylinder removal while maintaining the quality of printed matter called friction resistance. Further, the problem can be solved by using the present invention, and the effect does not depend on the paper used for printing or the printing press substrate.

  As a result of intensive studies to solve the above-mentioned conventional problems, the present inventors have identified an offset sheet-fed printing ink composition containing a wax, a binder resin, a vegetable oil, a petroleum solvent, and a pigment. The present invention was completed by finding an excellent property that a printed matter printed with an offset sheet-fed printing ink composition containing the above wax has excellent frictional resistance and can reduce impression cylinder removal during printing. It came to do.

That is, the present invention is an offset sheet-fed printing ink composition comprising a wax, a binder resin, a vegetable oil, a petroleum solvent, and a pigment.
The wax has an average particle size of 3.5 to 4.5 μm,
Melting point 290-340 ° C
and
Sphericality 0.2-0.7
Polytetrafluoroethylene wax
And
Average particle size 1.0-4.0 μm,
Melting point 100-200 ° C
and
Sphericality 0.9-1.0
The present invention relates to an offset sheet-fed printing ink composition characterized by being a polyethylene wax.

Furthermore, the present invention is the above-mentioned offset sheet, wherein the offset sheet-fed printing ink composition further comprises one or more kinds of wax selected from the following polyethylene wax A, polyethylene wax B and polyethylene wax C. The present invention relates to a leaf printing ink composition.
Polyethylene wax A is
Average particle size 0.5-1.0 μm,
Melting point 60-140 ° C
and
Sphericality 0.6-0.8
It is what is.
Polyethylene wax B
Average particle size 1.5-2.0 μm,
Melting point 80-140 ° C
and
Sphericality 0.6-0.8
It is what is.
Polyethylene wax C
Average particle size 4.0-7.0 μm,
Melting point 60-140 ° C
and
Sphericality 0.2-0.7
It is what is.

  The present invention also relates to the above-mentioned offset sheet-fed printing ink composition, wherein the vegetable oil is soybean oil or soybean oil ester.

  Furthermore, the present invention relates to the above-mentioned offset sheet-fed printing ink composition, wherein the petroleum solvent has an aniline point of 70 to 110 ° C and a boiling point of 230 to 350 ° C.

  Moreover, this invention relates to the printed matter characterized by printing said offset sheet-fed printing ink composition on a base material.

  In offset sheet-fed printing, there is a method of adding wax as a means of imparting friction resistance to the ink printed on the paper surface. By adding this wax, the ink is taken up by the offset sheet-fed printing press impression cylinder. It becomes easy. However, by selecting the specific wax of the present invention and its addition amount, the ink printed on the paper surface is maintained at the friction resistance, and the ink is taken to the offset printing press impression cylinder at the time of printing. It can be reduced. By reducing the removal of the impression cylinder, the printability is improved, and it is not necessary to frequently clean the impression cylinder, so that the work efficiency is improved.

  Hereinafter, the present invention will be described in detail.

  The offset sheet-fed printing in the present invention is an ink in which water and ink are supplied by a roll to a plate surface in which an image portion and a non-image portion are formed on the same plate surface, and only the image portion is formed by the repulsive action of both. Is transferred to a rubber sheet surface called a blanket, and a sheet is passed through the sheet so as to come into contact with the blanket and pressed from the back side of the printing surface for printing. A roll used for pressurization from the back side is called an impression cylinder.

  The term “rubbing resistance” in the present invention refers to the strength against rubbing between the paper surfaces of the ink on the paper surface and the objective. In general, a printed matter printed using an ink having good friction resistance is resistant to rubbing and is not easily damaged by rubbing.

  In general, in offset sheet-fed printing, there is a method of adding wax to ink as means for imparting friction resistance to ink printed on paper. This is because the dispersed wax protrudes from the surface of the ink after printing to reduce the contact area, or the wax itself spreads thinly to protect the ink surface. However, in order to provide wear resistance, simply adding a wax often causes the impression cylinder to be removed. On the other hand, in the offset sheet-fed printing ink of the present invention, when the following specific wax is added, the friction resistance is excellent and the impression cylinder is hardly taken.

  That is, in the present invention, the following polytetrafluoroethylene (PTFE) wax and polyethylene wax are used.

  The polytetrafluoroethylene (PTFE) wax in the present invention is a PTFE wax made of low molecular weight tetrafluoroethylene and excellent in friction resistance.

  That is, the average particle diameter is 3.5 to 4.5 μm (the average particle diameter is a laser diffraction / scattering type particle size distribution measuring device LA-920 type manufactured by Horiba, Ltd.), and the wax is referred to as SB-81. After dilution, the transmittance (L) (H) was adjusted to 90-95% and measured by the paste cell method (the same applies to other waxes), and the melting point was 290 to 340 ° C. ( The melting point was measured twice using a differential scanning calorimeter DSC6200 manufactured by Seiko Instruments Inc., and heating at a rate of 10 ° C./min and cooling at a rate of 5 ° C./min were repeated twice. The same)), and a PTFE wax having a sphericity of 0.2 to 0.7.

  The amount of PTFE wax added is preferably 0.15 to 1.20% by weight, more preferably 0.30 to 0.90% by weight, based on the total amount of the printing ink composition. If the addition amount is less than 0.15% by weight, sufficient friction resistance cannot be ensured, and if the addition amount exceeds 1.20% by weight, excessive wax is taken up by the impression cylinder.

  In addition, as the polyethylene wax used in the present invention, spherical polyethylene wax, polyethylene wax A, polyethylene wax B, and polyethylene wax C are appropriately used.

  The polyethylene wax A in the present invention is a fine polyethylene wax obtained by melting polyethylene manufactured using carbon monoxide gas and hydrogen gas as raw materials and adjusting the particle diameter to a predetermined particle size. The polyethylene wax has an average particle size of 0.5 to 1.0 μm, a melting point of 60 to 140 ° C., and a sphericity of 0.6 to 0.8. The amount of polyethylene wax A added is preferably 0.03 to 2.70% by weight, more preferably 0.30 to 1.50% by weight, based on the total amount of the printing ink composition. When the addition amount is less than 0.03% by weight, sufficient friction resistance cannot be secured, and when the addition amount exceeds 2.70% by weight, excessive wax is taken up by the impression cylinder.

  The polyethylene wax B in the present invention is a fine polyethylene wax prepared by melting polyethylene produced by polymerization of ethylene or thermal decomposition of polyethylene and adjusting it to a predetermined particle diameter. The polyethylene wax has an average particle diameter of 1.5 to 2.0 μm, a melting point of 80 to 140 ° C., and a sphericity of 0.6 to 0.8. The amount of polyethylene wax B added is preferably 0.03 to 2.25% by weight, more preferably 0.25 to 1.25% by weight, based on the total amount of the printing ink composition. If the addition amount is less than 0.03% by weight, sufficient friction resistance cannot be ensured. If the addition amount exceeds 2.25% by weight, excess wax is taken up by the impression cylinder.

  The polyethylene wax C in the present invention is excellent in friction resistance with a coarse and low sphericity ratio in polyethylene wax A and B ratios obtained by pulverizing polyethylene produced from carbon monoxide gas and hydrogen gas as raw materials and adjusting to a predetermined particle diameter. Polyethylene wax. Further, it is a polyethylene wax having an average particle diameter of 4.0 to 7.0 μm, a melting point of 60 to 140 ° C., and a sphericity of 0.2 to 0.7. The amount of polyethylene wax C added is preferably 0.04 to 1.05% by weight, more preferably 0.18 to 0.88% by weight, based on the total amount of the printing ink composition. If the addition amount is less than 0.04% by weight, sufficient friction resistance cannot be secured, and if the addition amount exceeds 1.05% by weight, excessive wax is taken up by the impression cylinder.

  The true spherical polyethylene wax in the present invention is a true spherical polyethylene wax in which polyolefin is dispersed in water in the form of fine particles and adjusted to a predetermined particle diameter. Further, it is a true spherical polyethylene wax having an average particle diameter of 1.0 to 4.0 μm, a melting point of 100 to 200 ° C., and a sphericity of 0.9 to 1.0 and excellent in friction resistance. The addition amount of the true spherical polyethylene wax is preferably 0.08 to 0.64% by weight, more preferably 0.16 to 0.48% by weight, based on the total amount of the printing ink composition. If the addition amount is less than 0.08% by weight, sufficient friction resistance cannot be ensured. If the addition amount exceeds 0.64% by weight, excessive wax is taken up by the impression cylinder.

The sphericity in the present invention is defined by the general formula (1). The particle size of the wax was evaluated by 1000 for each type of wax using SEM.
General formula (1)

  In the present invention, the total amount of PTFE wax, true spherical polyethylene wax and polyethylene wax C is within 1.80% by weight based on the total amount of the printing ink composition, and the above-mentioned three types of wax, polyethylene wax A and polyethylene wax are used. The total addition amount of B is within 3.00% by weight with respect to the total amount of the printing ink composition.

  In addition, when the above waxes are included in the ink composition for an offset sheet-fed printing press, a predetermined amount may be added to the ink composition for the offset sheet-fed printing press as a product, or may be added by a mixer at the time of manufacture. Good.

As an example of the offset sheet-fed printing ink composition of the present invention,
・ Pigment 5.00 to 25.00% by weight
-Binder resin 15.00-50.00 wt%
・ Vegetable oils 30.00 to 50.00% by weight
・ Petroleum solvent: 10.00 to 15.00% by weight
・ Drying accelerator 0.00 to 3.00% by weight
PTFE wax 0.15 to 1.20% by weight
・ Polyethylene wax A 0.00-2.70% by weight
-Polyethylene wax B 0.00-2.25% by weight
・ Polyethylene wax C 0.00 to 1.05% by weight
・ Spherical polyethylene wax 0.08 to 0.64% by weight
・ Other additives 0.00 to 10.00% by weight
Is mentioned. The ink type is mainly an offset sheet-fed printing ink composition, but is 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-based), β-naphthol-based, β-oxynaphthoic acid anilide-based, monoazo yellow-based, disazo Insoluble azo pigments such as yellow and pyrazolones, condensed azo pigments such as allyl acetoacetate and phthalocyanines, copper phthalocyanines (α blue, β blue, γ blue), halogenated copper phthalocyanines such as chlorine and bromine, metal free Examples of the phthalocyanine pigments and polycyclic pigments include perylene, quinacridone, thioindigo, dioxazine, isoindolinone, and quinophthalone pigments. The addition amount of the pigment is 5.00 to 25.00% 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 and petroleum resin, and these can be used alone or in combination of two or more. The binder resin preferably has a cloudiness temperature of 40 to 140 ° C. in a 10% diluted state of AF Solvent 6 manufactured by Nippon Oil Corporation. (The white turbidity temperature was measured with CHEMOTRONIC, manufactured by NOVOCONTROL, Inc.) If it is less than 40 ° C., sufficient gel elasticity cannot be obtained in the state of varnish, and if it exceeds 140 ° C., the affinity with the solvent deteriorates.

  As the binder resin used in the present invention, a resin obtained by adding a vegetable oil and / or a petroleum solvent and a gelling agent such as an aluminum chelate compound and dissolving at 190 ° C. or higher to be varnished can be used. . The addition amount of the binder resin is 15.00 to 50.00% 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. In 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, Japanese 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, coconut oil, peanut oil, dehydrated castor oil, and the like.

  The petroleum solvent used in the present invention is a crude oil-derived solvent (petroleum solvent) having an aromatic hydrocarbon content of 1% by weight or less. As the petroleum solvent, a petroleum solvent having an aniline point of 70 to 110 ° C. and a boiling point of 230 ° C. or more is suitable. When the aniline point is lower than 70 ° C., the ability to dissolve the resin is too high, so that the viscosity of the ink composition becomes too low and the stain resistance is not sufficient. On the other hand, when the aniline point exceeds 110 ° C., the solubility of the resin is poor, so that the fluidity of the ink composition is inferior, and as a result, only a printed matter with poor gloss and inking properties can be obtained. When the boiling point is less than 230 ° C., the amount of solvent released in the ink on the printing press increases, and the ink composition tends to deposit on rollers, plates, and blankets due to the deterioration of the fluidity of the ink composition. Therefore, it is not preferable.

  Examples of the drying accelerator used in the present invention include acetic acid, propionic acid, butyric acid, isopentanoic acid, hexanoic acid, 2-ethylbutyric acid, naphthenic acid, octylic acid, nonanoic acid, decanoic acid, 2-ethylhexanoic acid and isooctanoic acid. , Isononanoic acid, lauric acid, palmitic acid, stearic acid, oleic acid, linoleic acid, neodecanoic acid, versatic acid, secanoic acid, tall oil fatty acid, linseed fatty acid, soybean oil fatty acid, dimethylhexanoic acid, 3, 5, 5 -Metal salts of organic carboxylic acids such as trimethylhexanoic acid and dimethyloctanoic acid, such as calcium, cobalt, lead, iron, manganese, zinc, zirconium, salts, and other publicly known compounds can be used for printing. In order to promote the ink surface and internal curing, use a combination of these as appropriate. Rukoto can also.

Hereinafter, the present invention will be described with reference to specific examples, but the present invention is not limited to the following examples. In the present invention, “part” means “part by weight”, and “%” means “% by weight” unless otherwise specified.
[Examples 1 to 5]

  Stir 18 wt% pigment, 29 wt% binder resin, 32 wt% vegetable oil, 10 wt% petroleum solvent, 3 wt% drying accelerator and 4 wt% other additives. A product was made. To this ink composition, a wax was mixed according to the composition shown in Table 1, and the binder resin, vegetable oil and petroleum solvent were increased so that the total weight% of the ink composition was 100% by weight. Examples 1 to 5 were obtained by kneading again with a roll.

[比較例１〜５]

[Comparative Examples 1-5]

  Stir 18 wt% pigment, 29 wt% binder resin, 32 wt% vegetable oil, 10 wt% petroleum solvent, 3 wt% drying accelerator and 4 wt% other additives. A product was made. To this ink composition, a wax was mixed according to the formulation shown in Table 2, and the binder resin, vegetable oil and petroleum solvent were increased so that the total weight% of the ink composition was 100% by weight. The rolls were again kneaded to make Comparative Examples 1 to 5.

<Evaluation of impression cylinder taken>
Using the ink compositions obtained in Examples 1 to 5 and Comparative Examples 1 to 5, the front surface was printed with an offset sheet-fed printing press under the following conditions. In order to completely dry the ink composition on the paper surface, the ink composition was left to stand overnight and turned over and passed through the same machine. At this time, the adhesion of the ink composition to the first impression cylinder was visually evaluated. The evaluation results are shown in Table 7. The case where the ink composition was less adhered was rated as ◯, the case where the adhesion was very noticeable was marked as x, and the middle one was marked as Δ. Δ and x are not practical areas and are insufficient.
・ Paper: Pearl coat N
・ Printing speed: 15000 sph
-Number of printed sheets: 2000-Print density: Yellow 1.40, Red 1.50, Indigo 1.60, Black 1.80
(The density was measured with a density measuring machine attached to the printing press.)

<Friction resistance evaluation>
Using the ink compositions obtained in Examples and Comparative Examples, the front surface was printed with a sheet-fed printing machine under the following conditions. In order to completely dry the ink composition on the paper surface, the ink composition was allowed to stand overnight, and evaluated with a Gakushin type friction resistance tester. The evaluation results are shown in Table 3. The one with few scratches was marked with ◯, the one with severe scratches was marked with ×, and the middle one was marked with △. Δ and x are not practical areas and are insufficient.
・ Paper: Pearl coat N
・ Printing speed: 15000 sph
-Print density: Yellow 1.40, Red 1.50, Indigo 1.60, Black 1.80
(The density was measured with a density measuring machine attached to the printing press.)
・ Friction resistance tester: Gakushin type friction fastness tester manufactured by Tester Sangyo
Weight 200g, 10 round trips

  As shown in Table 3, in the ink compositions (Examples 1 to 5) containing 0.15 to 1.20% by weight of PTFE wax and 0.08 to 0.64% by weight of spherical polyethylene wax, The torso was evaluated with good results, and the evaluation of friction resistance was also good. On the other hand, in Comparative Examples 1-5, the impression cylinder was taken and the results were not sufficient in the evaluation or the friction resistance evaluation, and those having two performances were not obtained.

  Furthermore, in the printing press (manufactured by Komori Corporation), when the printed surface of the front surface was turned over and 100,000 sheets were printed, the ink compositions of practical examples 1 to 5 could be printed without problems, but the comparative example The ink compositions 1 to 5 had a printing trouble on the way, and it was necessary to stop printing and perform washing or the like.

Claims (5)

In an offset sheet-fed printing ink composition comprising a wax, a binder resin, a vegetable oil, a petroleum solvent and a pigment,
The wax has an average particle size of 3.5 to 4.5 μm,
Melting point 290-340 ° C
and
Sphericality 0.2-0.7
Polytetrafluoroethylene wax
And
Average particle size 1.0-4.0 μm,
Melting point 100-200 ° C
and
Sphericality 0.9-1.0
An offset sheet-fed printing ink composition characterized by being a polyethylene wax. The offset sheet-fed printing ink according to claim 1, further comprising at least one wax selected from the following polyethylene wax A, polyethylene wax B and polyethylene wax C contained in the offset printing ink composition. Composition.
Polyethylene wax A is
Average particle size 0.5-1.0 μm,
Melting point 60-140 ° C
and
Sphericality 0.6-0.8
It is what is.
Polyethylene wax B
Average particle size 1.5-2.0 μm,
Melting point 80-140 ° C
and
Sphericality 0.6-0.8
It is what is.
Polyethylene wax C
Average particle size 4.0-7.0 μm,
Melting point 60-140 ° C
and
Sphericality 0.2-0.7
It is what is.   The offset sheet-fed printing ink composition according to claim 1 or 2, wherein the vegetable oil is soybean oil or soybean oil ester.   The offset sheet-fed printing ink composition according to any one of claims 1 to 3, wherein the petroleum solvent has an aniline point of 70 to 110 ° C and a boiling point of 230 to 350 ° C.   A printed matter comprising a substrate printed with the offset sheet-fed printing ink composition according to claim 1.