JP7195103B2 - Penetration-drying offset printing ink, printed matter - Google Patents

Description

The present invention relates to a penetration drying offset printing ink and printed matter printed using the penetration drying offset printing ink composition.

Penetration-drying type offset printing ink, which is mainly used for newspaper printing, is a solvent component such as petroleum solvent and vegetable oil in the ink coating film printed on paper, which penetrates the inside of the paper by capillary action and spreads to the surface of the paper. A drying method is used in which the remaining solids such as pigments and resins form a solid film. As the ink supply method for the penetration drying type offset printing press, the urn method and the rail method have become mainstream along with the speeding up of the printing press and the improvement of the paper surface quality.

In penetrating-drying offset printing ink, if the solvent component leaves the ink film too quickly (short set time), problems such as guide roll residue and rear cylinder residue tend to occur. It is known that increasing the content of extender pigments such as kaolin and organic bentonite accelerates the ink setting, while decreasing the content of extender pigments slows the ink setting but increases fluidity. there is Also, alkyd resins are known to have the effect of slowing down the settability of printing ink, while also having the effect of increasing fluidity of ink. If the fluidity of the ink is high, problems such as sagging and misting tend to occur, and if the fluidity is low, problems such as sagging and poor ink transfer occur (Patent Documents 1 and 2).

Furthermore, in recent years, the weight reduction of printing paper has progressed. For low-weight paper, there is a tendency to increase the coating amount of a surface strength agent, etc., in order to compensate for the lack of strength on the paper surface, but in general, the setting property becomes faster as the coating amount increases. In addition, low-weight paper tends to cause the strike-through of printing ink, and in order to suppress this, thin-film printing is sometimes performed. Thin-film printing refers to printing with a thinner ink film than usual on a base material such as paper.In this case, printing ink with a higher pigment concentration than before is used so that the printing density does not decrease. There are many things. Since the ink film is thin, the amount of solvent that separates from the ink film is also small, and naturally the setting time tends to be short. Furthermore, in the case of high-concentration black ink, the pigment concentration is also high, so this tendency is accelerated.

Japanese Unexamined Patent Application Publication No. 2013-213112 JP 2017-110141 A

As described above, in recent years, the environment surrounding printing using penetrating drying type offset printing ink has an increasing number of factors that shorten the set time. However, when attempting to adjust the setting property of the ink by a known method, as described above, the fluidity increases as the setting property slows down. . That is, in the penetration drying type offset printing ink, both the setting property and the fluidity are kept in the range suitable for the penetration drying type offset printing, and the problems caused by the setting property such as guide roll residue and rear cylinder residue, and pot sagging and misting. It has been difficult to highly suppress both defects caused by fluidity.

It is an object of the present invention to provide a penetration drying type offset printing ink which is excellent in settability and fluidity.

The present invention contains a coloring pigment, an alkyd resin, and polymerized linseed oil, the content of the alkyd resin is 1% by mass or more and 7% by mass or less, and the content of the polymerized linseed oil is 1% by mass or more and 7% by mass. % or less, and the total content of alkyd resin and linseed oil is 2% by mass or more and 10% by mass or less.

According to the penetration drying type offset printing ink of the present invention, both the setting property and the fluidity can be kept within a range suitable for penetration drying type offset printing, and the setting properties such as guide roll residue and rear cylinder residue It is possible to highly suppress both defects and defects caused by fluidity such as jar sagging and misting.

<Penetration-drying type offset printing ink>
The penetration drying type offset printing ink of the present invention contains a color pigment, an alkyd resin, and polymerized linseed oil, the content of the alkyd resin is 1% by mass or more and 7% by mass or less, and the content of the polymerized linseed oil is 1% by mass or more and 7% by mass or less, and the total content of alkyd resin and linseed oil is 2% by mass or more and 10% by mass or less. The penetration drying type offset printing ink of the present invention will be described in detail below. In the following, the penetrating drying type offset printing ink is also simply referred to as printing ink.

The coloring pigment used in the printing ink of the present invention is not particularly limited, and various organic pigments and inorganic pigments can be used. For example, yellow pigments include disazo yellow (Pigment Yellow 12, Pigment Yellow 13, Pigment Yellow 17, Pigment Yellow 1), Hansa Yellow, etc., and magenta pigments include Brilliant Carmine 6B, Lake Red C, Watching Red, etc. is mentioned. Examples of cyan pigments include phthalocyanine blue, phthalocyanine green, and alkali blue, and examples of black pigments include carbon black such as furnace carbon black and channel black, and aniline black.

When the color pigment is a color pigment such as a yellow pigment, a magenta pigment, or a cyan pigment, the content of the color pigment is adjusted in the range of 7% by mass to 21% by mass based on the total amount of the printing ink. Usually, it is adjusted in the range of 7 to 17% by mass of the total amount of printing ink, but when used for thin film printing, it is preferably 11 to 21% by mass.
When the color pigment is a black pigment such as carbon black, the content of the color pigment is adjusted in the range of 15% by mass or more and 38% by mass or less with respect to the total amount of the printing ink. Although it is usually adjusted in the range of 15% by mass or more and 21% by mass or less, it is preferably 25% by mass or more and 38% by mass or less when used for thin film printing.

Although the present invention is sufficiently effective even with printing inks having a pigment concentration of about the level used in ordinary printing, printing inks containing a coloring pigment at a high concentration such as those used for thin-film printing, particularly containing a black pigment at a high concentration. Suitable for high density black ink. In thin-film printing, the ink film thickness is thin, so the set time is short, and this tendency is particularly noticeable in high-concentration black ink with a pigment content of 25% by mass or more as described above. Even with a high-density black ink, the settability and fluidity can be kept within a suitable range.

When the color pigment is carbon black, it is preferable to use carbon black having a DBP (dibutyl phthalate) oil absorption of 50 cm ³ /100 g or more and 70 cm ³ /100 g or less. High-concentration black ink tends to set quickly due to the high pigment concentration. can slow down sex.

The proportion of carbon black having a DBP oil absorption of 50 cm ³ /100 g or more and 70 cm ³ /100 g or less in the total amount of carbon black may be appropriately adjusted in consideration of the setting time. As an example, the content is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more. The total amount of carbon black may be carbon black having a DBP oil absorption of 50 cm ³ /100 g or more and 70 cm ³ /100 g or less.

The printing ink of the present invention may contain an extender. Extender pigments are not particularly limited, and one or two of known pigments such as clay such as roseite clay, talc, barium sulfate, calcium carbonate, heavy calcium carbonate, barium carbonate, silica, organic bentonite, titanium oxide, etc. The above can be used. These extender pigments may be surface-treated with rosin acid or the like, or may be untreated.

The printing inks of the present invention contain varnishes. Resin components of varnish include phenolic resin, petroleum resin, rosin-modified phenolic resin, petroleum-resin-modified phenolic resin, rosin ester, alkyd resin, modified alkyd resin, rosin-modified maleic acid resin, gilsonite resin, acrylic resin, urethane resin, Epoxy resin and the like can be mentioned, and there is no particular limitation. Among these resins, rosin-modified phenolic resins, petroleum resins and gilsonite resins are preferably used, and which resin to use is appropriately selected depending on the combination with the coloring pigment.

Rosin-modified phenolic resins and petroleum resins are preferably used for printing inks using color pigments such as yellow pigments, magenta pigments and cyan pigments. It is preferable to use a rosin-modified phenolic resin, a petroleum resin, or a gilsonite resin for a printing ink using a carbon black pigment.

The rosin-modified phenolic resin is obtained by reacting rosins such as gum rosin, wood rosin, tall oil rosin and natural rosin with alkylphenol, formaldehyde and polyol such as glycerin and pentaerythritol. A weight average molecular weight of 10,000 to 300,000 is preferred.

Petroleum-based resins are aromatic and aliphatic hydrocarbon resins obtained by refining and polymerizing unsaturated hydrocarbons obtained from petrochemical manufacturing processes as raw materials. "Neopolymer 120", "Neopolymer 140" and "Neopolymer 170S" manufactured by JX Nippon Oil & Energy Corporation; "Petcol 120" and "Petcol 140" manufactured by Tosoh Corporation;

Gilsonite resin is an aliphatic hydrocarbon resin with a softening point of 110 to 180° C. extracted from natural asphaltite mined from natural veins. Main components include asphaltenes, resins, and oils, such as those manufactured by American Gilsonite.

The varnish is obtained by adding a chelating agent and other auxiliary agents to the resin and solvent such as vegetable oil or petroleum solvent, if necessary, and heating and stirring the mixture.

Vegetable oils include non-drying oils such as castor oil, peanut oil, and olive oil; semi-drying oils such as soybean oil, cottonseed oil, rapeseed oil, sesame oil, and corn oil; A plant-derived component such as a plant ester can be used.

Recycled vegetable oils can also be used as vegetable oils. Recycled vegetable oil is vegetable oil that has been recovered from oils used for cooking or the like and regenerated. As the regenerated vegetable oil, an oil that has been regenerated with a water content of 0.3% by mass or less, an iodine value of 90 or more, and an acid value of 3 or less is preferable, and an iodine value of 100 or more is more preferable. By reducing the water content to 0.3% by mass or less, it is possible to remove impurities that affect the emulsification behavior of the ink, such as salt contained in the water. In other words, it is possible to improve the oxidative polymerization property, and furthermore, by selecting and regenerating the vegetable oil having an acid value of 3 or less, it is possible to suppress excessive emulsification of the ink. Examples of methods for regenerating the recovered vegetable oil include filtration, removal of precipitates by standing, and decolorization using activated clay or the like.

Examples of fatty acid esters include soybean oil fatty acid methyl ester, soybean oil fatty acid butyl ester, soybean oil fatty acid isobutyl ester, soybean oil fatty acid 2-ethylhexyl ester, linseed oil fatty acid butyl ester, linseed oil fatty acid isobutyl ester, and tall oil fatty acid butyl ester. Ester, tall oil fatty acid 2-ethylhexyl ester, tall oil octyl ester, tall oil fatty acid pentaerythritol ester, palm oil fatty acid methyl ester, palm oil fatty acid butyl ester, palm oil fatty acid isobutyl ester, palm oil fatty acid 2-ethylhexyl ester, castor oil Examples include fatty acid methyl ester, castor oil fatty acid butyl ester, castor oil fatty acid isobutyl ester, and castor oil fatty acid 2-ethylhexyl ester.

Hydrocarbons having 6 to 20 carbon atoms are preferably used as petroleum solvents. Specifically, paraffinic solvents such as n-pentane, isopentane, n-hexane, 2-methylpentane, n-heptane, n-octane, and trimethylpentane; naphthenes such as cyclohexane, cyclohexylmethane, octadecylcyclohexane, and methylisopropylcyclohexane; "AF Solvent No. 4", "AF Solvent No. 5", "AF Solvent No. 6" and "AF Solvent No. 7" manufactured by JX Nippon Oil & Energy Corporation.

Chelating agents include, for example, derivatives of aluminum n-butoxide, aluminum-iso-butoxide and aluminum-sec-butoxide, wherein one of the n-butoxy, iso-butoxy and sec-butoxy groups is A compound substituted with ethyl acetate or methyl acetoacetate can be used.

The printing ink of the present invention comprises an alkyd resin and polymerized linseed oil. According to the inventors' intensive studies, the alkyd resin has the effect of slowing down the settability of the printing ink and at the same time improving the fluidity of the printing ink. However, the extent of this is, of course, different from the amount of variation that accompanies changes in the content of coloring pigments and extender pigments in ink, which are also known factors that affect settability and fluidity. For example, if the content of a coloring pigment is increased, as in a high-concentration ink, the setting property becomes faster and the fluidity becomes lower. Too much liquidity. Therefore, when alkyd resin and polymerized linseed oil are used in combination, it was found that setting property can be delayed while suppressing improvement in fluidity.

The alkyd resin (also referred to as alkyd resin) used in the present invention is a resin obtained by modifying a polyester of polybasic acid and polyol with oil and fatty acid as a base. The content of the alkyd resin in the printing ink of the present invention is 1% by mass or more and 7% by mass or less. If the content of the alkyd resin in the printing ink is too low, the effect of slowing down the setting of the printing ink will be weak. is likely to give

Polybasic acids used to prepare alkyd resins include phthalic acid, isophthalic acid, terephthalic acid, succinic acid, maleic acid, itaconic acid, fumaric acid, tetrahydrophthalic acid, hexahydrophthalic acid, methyltetrahydrophthalic acid, and adipic acid. , sebacic acid, azelaic acid, hymic acid anhydride (a product of Hitachi Chemical Co., Ltd.; registered trademark), trimellitic acid, methylcyclohexene tricarboxylic acid or pyromellitic acid, dimer acids derived from unsaturated fatty acids, or these anhydrides and the like, which may be used singly or in combination of two or more. Aromatic carboxylic acids are preferred in consideration of the emulsifiability of the ink.

Examples of polyols used for preparing alkyd resins include ethylene glycol, polyethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, polypropylene glycol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2,2-dialkyl-1,3- Propanediol, 2,4,4-trimethyl-1,3-pentanediol, butylene glycol, diols having an alicyclic structure such as hydrogenated bisphenol A, adducts of ethylene oxide of bisphenol A, propylene oxide of bisphenol A Dihydric alcohols such as adducts, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol and the like can be mentioned, and can be used alone or in combination of two or more.

In addition to the polybasic acid and polyol described above, a polyol containing a carboxyl group may also be used. Examples of polyols containing carboxyl groups include dimethylolpropionic acid, dimethylolbutanoic acid, and diphenolic acid, which may be used singly or in combination of two or more.

Oils and fatty acids used for denaturation include linseed oil, soybean oil, corn oil, sunflower oil, olive oil, sesame oil, safflower oil, Chinese tung oil, hempseed oil, perilla oil, tall oil, rice bran oil, castor oil, and dehydrated castor oil. , Rapeseed oil, cottonseed oil, coconut oil, fish oil, squid liver oil, and other animal and vegetable oils, their fatty acids, and high-diene fatty acids, etc. Saturated fatty acids and the like can be mentioned, and they may be used singly or in combination of two or more.

The alkyd resin used in the present invention is not particularly limited, but has a solid content acid value of 1 mgKOH/g or more and 5 mgKOH/g or less, or a solid content hydroxyl value of 5 mgKOH/g or more and 15 mgKOH/g or less. is preferred. More preferably, the alkyd resin has a solid content acid value of 1.5 mgKOH/g or more and 5 mgKOH/g or less. Further, it is more preferable to use an alkyd resin having a solid content acid value of 1 mgKOH/g or more and 5 mgKOH/g or less and a solid content hydroxyl value of 5 mgKOH/g or more and 15 mgKOH/g or less. By including such an alkyd resin, it is possible to obtain a printed material with excellent glossiness, and to suppress excessive emulsification of the printing ink which may occur when a general alkyd resin is included as a varnish component.

Further, when the concentration of the color pigment is increased, the oil length of the alkyd resin affects the dispersibility and kneadability of the color pigment, the fluidity of the printing ink, and the like. In general, if the oil length is too short, the effect of improving the pigment dispersibility and fluidity is weak, and if it is too high, stains tend to occur during printing. The oil length of the alkyd resin used in the present invention is preferably 50% or more and 90% or less.

The polymerized linseed oil used in the present invention is obtained by heating and stirring linseed oil. The polymerization reaction may be thermal polymerization or oxidative polymerization. The content of polymerized linseed oil in the printing ink of the present invention is 1% by mass or more and 7% by mass or less. If the content of the polymerized linseed oil in the printing ink is too low, there is a risk that the effect of adjusting the setting properties and fluidity will not be sufficiently obtained. It may affect the physical properties of printing ink.

The polymerized linseed oil used in the present invention preferably has a viscosity at 25° C. of 50 dPa·s or more, more preferably 70 dPa·s or more, and more preferably 80 dPa·s or more. If the viscosity at 25° C. is less than 50 dPa·s, the improvement in fluidity may not be sufficiently suppressed depending on the content of the alkyd resin. There is no particular upper limit for the viscosity of the polymerized linseed oil, but if the viscosity is too high, productivity may be affected. From this point of view, the viscosity at 25 ° C. of polymerized linseed oil measured with an E-type viscosity system is preferably 150 dPa s or less, more preferably 120 dPa s or less, and more preferably 100 dPa s or less. preferable. The viscosity of the polymerized linseed oil is measured using an E-type viscometer at a cone rotor of 3°×R24 and a rotation speed of 100 rpm.

The polymerized linseed oil used in the present invention preferably has an iodine value of 110 or less, more preferably 105 or less after polymerization. As a result, a printing ink having excellent stability over time can be obtained.

The total content of alkyd resin and polymerized linseed oil contained in the printing ink of the present invention is 2% by mass or more and 10% by mass or less of the printing ink. If the total content of the alkyd resin and the polymerized linseed oil is less than 2% by mass, there is a risk that the effect of adjusting the setting properties and fluidity will not be sufficiently obtained. If the amount exceeds 10% by mass, the effect gradually reaches a plateau, and depending on the acid value and hydroxyl value of the alkyd resin, the ink may be over-emulsified during printing, or ink transfer failure may occur between the rollers of the printing machine. . More preferably, the total content of alkyd resin and polymerized linseed oil is 4 mass % or more of the printing ink. More preferably, the total content of alkyd resin and polymerized linseed oil is 8 mass % or less of the printing ink.

The printing ink of the present invention contains auxiliary agents such as an anti-skinning agent, a viscosity modifier, a polyethylene-based or fluorine-based film-strengthening agent, a dispersant, an anti-fouling agent, an emulsification modifier, and an antioxidant, if necessary. You can stay. As these auxiliary agents, conventionally known ones can be suitably used.

<Manufacturing method>
The printing ink of the present invention can be produced by a conventionally known method using the raw materials described above. As an example, a varnish prepared using a resin, vegetable oil, petroleum-based solvent, etc. is added with a coloring pigment, and if necessary, an extender pigment, a solvent, and other additives. Perform kneading with a shot mill, roll mill, or the like. After kneading, varnish, petroleum solvent, vegetable oil, other waxes, antioxidants, emulsification modifiers and other auxiliaries are added and thoroughly stirred and mixed. The alkyd resin and polymerized linseed oil may be added during premixing or after kneading. The alkyd resin and polymerized linseed oil may be added at the same time, or may be added at different stages, eg, the alkyd resin is added during premixing and the polymerized linseed oil is added after milling.

The amount of these raw materials used is adjusted according to the viscosity and fluidity required for the printing ink. Moreover, the timing of addition of these raw materials is not fixed, but is appropriately adjusted based on the state of mixing.

EXAMPLES The present invention will be described below with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Compositions and other numerical values are based on mass unless otherwise specified.

1. Preparation of materials 1.1 Preparation of rosin-modified phenolic resin varnish Rosin-modified phenolic resin (weight average molecular weight 100,000, softening point 161 ° C., acid value 18.0 mg KOH / g): 45 parts, soybean oil (manufactured by Nisshin OilliO Co., Ltd.): 25 parts, and AF Solvent No. 6: 14.5 parts were charged and heated and stirred at 180° C. for 1 hour. After that, 15 parts of AF Solvent No. 6 and 0.5 parts of aluminum ethyl acetoacetate diisopropylate (ALCH-50F manufactured by Kawaken Fine Chemicals Co., Ltd.) were added to obtain a rosin-modified phenol resin varnish. This rosin-modified phenolic resin varnish was used in Examples and Comparative Examples.

1.2 Alkyd resin preparation Soybean oil: 700 parts, glycerin: 48.5 parts, pentaerythritol: 53.8 parts were placed in a reaction vessel equipped with a stirrer, a rectifying column and a thermometer, and held at 250 ° C. for 1 hour. alcohol exchange reaction was carried out. After cooling to 150° C., 250.8 parts of isophthalic acid and xylene for reflux were added, and the mixture was gradually heated to 250° C., and the mixture was maintained for 8 hours to carry out an esterification reaction while dehydrating. While maintaining the temperature at 250° C., the reaction was carried out under reduced pressure for 2 hours to remove xylene and obtain an alkyd resin having a solid content acid value of 3.5 mgKOH/g, a solid content hydroxyl value of 11.0 mgKOH/g and an oil length of 70.

1.3 Preparation of Gilsonite Resin Varnish 25 parts of Gilsonite resin (Gilsonite Select 347 manufactured by American Gilsonite) and 75 parts of soybean oil were charged into a four-necked flask equipped with a condenser, thermometer and stirrer. The mixture was heated and stirred at 150° C. for 1 hour to obtain a Gilsonite resin varnish.

2. Preparation of printing ink Carbon black, rosin-modified phenolic resin varnish, alkyd resin, polymerized linseed oil, and Gilsonite resin varnish were mixed according to the formulation shown in Tables 2 and 3 with a three-roll mill so that the particle size of coarse particles in the printing ink was 5 μm or less. Soybean oil, a petroleum solvent (AF Solvent No. 6), and an anti-drying agent were mixed to obtain printing inks of Examples, Comparative Examples, and Reference Examples. The drying inhibitor in the table is 2,6-di-tert-butyl-4-cresol (H-BHT, manufactured by Honshu Chemical Industry Co., Ltd.), and the concentration of 2,6-di-tert-butyl-4-cresol is A solution dissolved in a petroleum-based solvent was used so as to have a concentration of 15% by mass.

The carbon blacks used in Examples and Comparative Examples are as follows.

The polymerized linseed oil used had a viscosity of 90.0 dPa·s at 25° C. measured with an E-type viscometer using a cone rotor of 3°×R24 and a rotation speed of 100 rpm.

3. Evaluation 3.1 Fluidity Fluidity is evaluated according to 4.1.4 (Test method for fluidity by glass plate fluidity system) of "Test method for newspaper offset rotary ink Group standard: 2000 (published by Newspaper Ink Association)". did. In this test method, a glass plate with a smooth surface is placed vertically, and fluidity is evaluated by measuring the length that a given amount of ink sample flows on the glass plate under its own weight within a given period of time.
The fluidity of printing ink is related to various troubles during printing. If the fluidity is too high, there are concerns about pot sagging, misting, etc., and if the fluidity is too low, pot lifting and poor transfer tend to occur. Evaluation was made in the following four stages.
○: 30 mm or more and 60 mm or less △: 60 mm or more and 100 mm or less × 1: over 100 mm × 2: less than 30 mm

3.2 Setability A color development sample was prepared using an RI tester. A blank sheet of paper was placed on the developed surface of the color sample, and this was sandwiched between the ink set time measuring devices, and pressure was applied while shifting the position at regular intervals to measure the time until the ink did not transfer to the blank sheet. Evaluation was made in the following three stages.
○: 40 minutes or more △: 30 minutes or more and less than 40 minutes ×: less than 30 minutes

As is clear from the Examples and Comparative Examples, the printing ink of the present invention was excellent in fluidity and settability.
On the other hand, the printing ink of the comparative example, which did not use both the alkyd resin and the polymerized linseed oil, could not keep both the fluidity and the setting property within the favorable ranges.

Claims (5)

a coloring pigment;
an alkyd resin having a solid content acid value of 1 mgKOH/g or more and 5 mgKOH/g or less, or a solid content hydroxyl value of 5 mgKOH/g or more and 15 mgKOH/g or less, and an oil length of 50% or more and 90% or less ;
Polymerized linseed oil having a viscosity of 50 dPa s or more and 150 dPa s or less at 25 ° C. ,
The content of the alkyd resin is 1% by mass or more and 7% by mass or less, the content of the polymerized linseed oil is 1% by mass or more and 7% by mass or less, and the content of the alkyd resin and the content of the linseed oil A penetration-drying offset printing ink in which the sum of The penetration drying type offset printing ink according to claim 1, wherein the polymerized linseed oil has a viscosity at 25°C of 50 dPa·s or more and 100 dPa·s or less . The penetration drying offset printing ink according to any one of claims 1 or 2, wherein the color pigment contains carbon black having a dibutyl phthalate oil absorption of 50 cm ³ /100 g or more and 70 cm ³ /g or less. 4. The penetration drying type offset printing ink according to claim 3, wherein the ratio of the carbon black having a dibutyl phthalate oil absorption of 50 cm ³ /100 g or more and 70 cm ³ /g or less in the color pigment is 10% by weight or more. . A printed matter printed with the penetrating drying offset printing ink according to any one of claims 1 to 4.