JP5777230B1 - Ink for offset lithographic printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink for offset lithographic printing in which the balance of on-machine stability, emulsification suitability, and heat setability, which has been difficult with conventional ink formulations, is balanced, and each characteristic is equal to or higher than that of conventional products. It is in. An offset lithographic printing ink comprising a rosin-modified phenolic resin varnish, vegetable oil, calcium carbonate, and an organic solvent, wherein (1) the tolerance value of the rosin-modified phenolic resin varnish is 5 to 50 (mL / 3 g) (2) The content of vegetable oil is 15 to 30% by mass, (3) the content of calcium carbonate is 8 to 25% by mass, and (4) the content of organic solvent is 15 to 40% by mass. By offset lithographic printing ink. [Selection figure] None

Description

  The present invention relates to an offset lithographic printing ink containing a specific rosin-modified phenolic resin varnish, vegetable oil, calcium carbonate, and an organic solvent in a specific ratio.

  In lithographic offset printing, water and oil repel each other, and by supplying dampening water at the same time as supplying ink to the plate, there is a difference in the ink depositing property between the image area and the non-image area. And an ink image is formed. However, when subjected to a shearing force between the printing press rollers, water easily enters the ink and the ink becomes emulsified. For this reason, a very delicate balance is required between the supply amount of ink and water, and if this balance is lost, it causes stains and roller stripping, so an ink having excellent emulsification ability is required. In recent high-speed printing, there has been a demand for inks having better emulsification suitability and on-machine stability.

Since the surface area of calcium carbonate increases as the particle size decreases, the part that has not been surface-treated becomes particularly easily emulsified when incorporated into the ink. Further, when the amount of calcium carbonate in the ink is increased, the resin component is decreased, so that the heat setting property is improved, but it is easy to tighten on the machine and the stability on the machine is lowered.
Moreover, when a fatty acid component is contained in vegetable oil, it is effective as an emulsification suppression aid.
On the other hand, when the solvent is replaced with vegetable oil, the ink is less likely to be tightened on the machine, so that the machine stability is improved while the heat setting property is lowered. Therefore, in the conventional heat set ink, 7-15 mass% vegetable oil is mix | blended in the ink.

Furthermore, since the number of polar groups changes when the tolerance of the rosin-modified phenol resin is changed, there is an emulsification adjustment effect. That is, when the tolerance is high, emulsification becomes difficult, and when the tolerance is low, emulsification becomes easy. To increase the tolerance, it is common to adjust the viscosity at the resin synthesis stage or to reduce the molecular weight of the resin by transesterification with vegetable oil components. Will decline.
By combining these factors in combination, there has been no report on an ink in which on-machine stability, emulsification suitability, and heat setting properties are balanced, and each characteristic is equal to or higher than that of a conventional product.

For example, in Patent Document 1, in a lithographic printing ink composition containing a pigment, calcium carbonate, a binder resin, a petroleum solvent, and a vegetable oil, the primary particle diameter of calcium carbonate is 0.02 to 0.10 μm, and the surface treatment agent A lithographic printing ink composition characterized in that rosin acid and / or fatty acid is used, the binder resin has a weight average molecular weight of 20,000 to 100,000, and a normal paraffin cloudiness temperature of 40 to 110 ° C. is described. Is 0.1 to 8% by weight in the total ink composition.
An object of the invention of this document relates to an improvement in printing quality and an improvement in a printing work environment, and furthermore, it is to provide an ink that is excellent in fleshing property and gloss and can reduce misting.

Patent Document 2 discloses an oxidation polymerization type offset printing ink composition containing amorphous silica, binder resin, vegetable oil, petroleum solvent and pigment, wherein the average secondary particle size of amorphous silica is Oxidation polymerization type offset having 0.05 to 0.10 μm, BET specific surface area of 20 to 400 m ² / g, and 0.1 to 10% by weight based on the total weight of the ink An ink composition is described, and an object of the invention of this document is to provide an offset ink composition having excellent fluidity and stability over time of ink and emulsification stability during printing, and a printed matter using the same. is there.

JP 2013-139551 A JP 2013-216735 A

In the prior art, an ink containing 8% or more of calcium carbonate has a drawback that the on-machine stability is lowered.
In addition, none of the conventional techniques can provide an offset lithographic printing ink that has a good balance of on-machine stability, emulsification suitability, and heat setting. Therefore, the problem of the present invention is that it is difficult for conventional ink formulations, and it is possible to balance the on-machine stability of ink, emulsification suitability, and heat setability, and for offset lithographic printing whose characteristics are equal to or higher than those of conventional products. To provide ink.

  The present invention solves the above problems by providing an ink for offset lithographic printing containing a specific ratio of rosin-modified phenolic resin varnish, vegetable oil, calcium carbonate, and an organic solvent having a specific tolerance value.

The present invention solves the drawbacks of the prior art by blending a large amount of vegetable oil and increasing the rosin-modified phenolic resin varnish n-heptane tolerance value. In addition, the emulsification suitability can be adjusted by controlling the primary particle size of calcium carbonate, the amount of surface treatment agent, and the amount of vegetable oil, so it is stable on the machine by adjusting the specific formulation and its ratio. Control of emulsification, emulsification ability, and heat setability.
That is, according to the present invention, it is possible to provide an ink for offset lithographic printing in which the on-machine stability, emulsification suitability, and heat setability of the ink are balanced, and each characteristic is equal to or higher than that of the conventional product.
Further, by increasing the amount of calcium carbonate and vegetable oil, the amount of solvent VOC in the ink) is significantly reduced. Therefore, there is an effect as an environmentally friendly ink by reducing the VOC amount.

That is, the present invention comprises the following items.
1. An offset lithographic printing ink containing rosin-modified phenolic resin varnish, vegetable oil, calcium carbonate, and an organic solvent,
(1) The tolerance value of rosin-modified phenolic resin varnish is 5 to 50 (mL / 3 g),
(2) The content of vegetable oil is 15 to 30% by mass,
(3) The content of calcium carbonate is 8 to 25% by mass,
(4) The content of the organic solvent is 15 to 40% by mass,
Offset lithographic printing ink, characterized by
2. 1. The primary particle diameter of calcium carbonate is 30 to 150 nm. Ink for offset lithographic printing as described in
3. 1. Offset lithographic printing is heat set printing. Or 2. Ink for offset lithographic printing as described in
4.1. ~ 3. Printed matter printed using the offset lithographic printing ink according to any one of the above.

(Rosin-modified phenolic resin varnish)
The rosin-modified phenolic resin varnish used in the present invention is characterized by an n-heptane tolerance value of 5 to 50 (mL / 3 g).
The tolerance value can be measured by a generally known method. For example, while maintaining 3 g of varnish at 25 ° C., n-heptane is added dropwise, and when n-heptane is completely clouded, mL) is n-heptane tolerance (unit: mL / 3 g).

  The rosin-modified phenolic resin varnish that can be used in the present invention is obtained by a known synthesis method. That is, the synthesis method is, for example, a method in which a vegetable oil component and an organic solvent are added to a known rosin-modified phenolic resin to dissolve it, a transesterification reaction with the vegetable oil component, and a chelation reaction using an aluminum chelate. At this time, select rosin-modified phenolic resins with different molecular weights, and as other binder resins, petroleum resin, alkyd resin, rosin-modified alkyd resin, petroleum resin-modified alkyd resin, rosin ester, etc. By making full use of the method of changing the temperature, the method of changing the temperature of transesterification, etc., it becomes possible to adjust to a predetermined tolerance value using any rosin-modified phenolic resin.

  The solvent used in the present invention has a boiling point range of 230 to 290 ° C., and typical solvent examples include AF Solvent Nos. 4 and 7 manufactured by JX Nippon Oil & Energy and / or ISU Chemical Co., Ltd. LTD's DSOL240, 260SP, 260C can be used. It is also possible to use AF Solvent Nos. 5 and 6 in combination as long as the drying property required for off-wheel printing is not reduced.

In the present invention, by setting the n-heptane tolerance value to 5 to 50 (mL / 3 g), it is possible to compensate on-machine stability and emulsification suitability that are reduced by increasing the amount of calcium carbonate. When a rosin-modified phenolic resin varnish having a tolerance value smaller than 5 is used, the on-machine stability is not lowered even if used alone, but when the amount of calcium carbonate is increased, the on-machine stability is inferior as a result. It becomes printing ink. Moreover, since many polar groups remain, the emulsification ability is also deteriorated, which is not preferable.
On the other hand, use of a varnish having a tolerance value greater than 50 improves the on-machine stability, but is not preferable because the drying property decreases.

(Vegetable oil)
The vegetable oil used in the present invention is characterized in that the content thereof is 15 to 30% by mass in the offset lithographic printing ink of the present invention.
If it is less than 15% by mass, the on-machine stability tends to decrease, and if it is more than 30% by mass, the heat setting property decreases, which is not preferable.

  Examples of vegetable oil components used in the present invention include oils such as soybean oil, linseed oil, rice oil, giraffe oil, castor oil, dehydrated castor oil, corn oil, safflower oil, Nanyang oil paulownia oil, canol oil, and thermal polymerization thereof. There are oil and oxidative polymerization oil. As vegetable oil fatty acid ester, linseed oil fatty acid methyl ester, linseed oil fatty acid ethyl ester, linseed oil fatty acid propyl ester, linseed oil fatty acid butyl ester, soybean oil fatty acid methyl ester, soybean oil fatty acid ethyl ester, soybean oil fatty acid propyl ester, large Bean oil fatty acid butyl ester, palm oil fatty acid methyl ester, palm oil fatty acid ethyl ester, palm oil fatty acid propyl ester, palm oil fatty acid butyl ester, castor oil fatty acid methyl ester, castor oil fatty acid ethyl ester, castor oil fatty acid propyl ester, castor oil fatty acid butyl ester, southern ocean Oil tung oil esters and the like can be used as well. In addition, as ethers made from vegetable oil, di-n-octyl ether, di-nonyl ether, dihexyl ether, nonyl hexyl ether, nonyl butyl ether, diheptyl ether, didecyl ether, nonyl octyl ether and the like can be used as well. Can be mentioned. The vegetable oil component can be used even if it is a regenerated vegetable oil. Regenerated vegetable oil is vegetable oil that has been recovered and regenerated. The regenerated vegetable oil is preferably an oil 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, more preferably an iodine value of 100 or more. By making the water content 0.3% by mass or less, it becomes possible to remove impurities that affect the emulsification behavior of the ink, such as salt contained in moisture. That is, it becomes possible to make it good in oxidative polymerizability, and it becomes possible to suppress over-emulsification of ink by selecting and regenerating vegetable oil having an acid value of 3 or less. Examples of the method for regenerating the recovered vegetable oil include, but are not limited to, filtration, removal of precipitates by standing, and decolorization by activated clay.

(Calcium carbonate)
The calcium carbonate used in the present invention is characterized by a content of 8 to 25% by mass in the offset lithographic printing ink of the present invention.
As the calcium carbonate, known and commonly used calcium carbonate can be used, and those having a primary particle diameter of 30 to 150 nm are particularly preferable.

(Organic solvent)
Examples of the organic solvent used in the present invention include known conventional solvents used in inks, such as AF Solvent Nos. 4 and 7 manufactured by JX Nippon Oil & Energy and ISU Chemical Co., Ltd. LTD DSOL240, 260SP, 260C, etc. In addition, AF solvent No. 5, No. 6, etc. may be used together to such an extent that drying property does not fall.
In the present invention, the content of the organic solvent in the offset lithographic printing ink is preferably 15 to 40% by mass, and if it is less than 15% by mass, the heat setting property is undesirably lowered.

(Other ingredients)
Other components mainly include pigments, binder resins other than rosin-modified phenolic resins, waxes, auxiliaries and the like.
Arbitrary inorganic and organic pigments can be used as the pigment used in the present invention. Examples of inorganic pigments include yellow lead, zinc yellow, bitumen, barium sulfate, cadmium red, titanium oxide, zinc white, petal, alumina white, ultramarine blue, carbon black, graphite, aluminum powder, and organic pigments. The pigments used in offset inks such as azo, phthalocyanine, quinacridone, anthraquinone and dioxazine are equivalent. Regarding organic pigments, for example, copper phthalocyanine pigments (CI Pigment Blue 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, CI Pigment Green 7, 36) Monoazo pigments (CI Pigment Red 3, 4, 5, 23, 48: 1, 48: 2, 48: 3, 48: 4, 49: 1, 49: 2, 53: 1, 57: 1 ), Disazo pigments (CI Pigment Yellow 12, 13, 14, 17, 83), anthraquinone pigments (CI Pigment Red 177), quinacridone pigments (CI Pigment Red 122, C.I.). CI Pigment Violet 19), dioxazine pigments (CI Pigment Violet 23), and the like. Not intended to be. Examples of the binder resin excluding the rosin-modified phenol resin include petroleum resins, alkyd resins, rosin-modified alkyd resins, petroleum resin-modified alkyd resins, and rosin esters. As the wax, a general wax used in printing ink can be used. For example, carnauba wax, beeswax, paraffin wax, microcrystalline wax, polyethylene wax, fatty acid amide, polytetrafluoroethylene and the like. A small amount of a known surfactant may be added as an auxiliary agent for the purpose of finely adjusting emulsification suitability.
These components can be appropriately used in a ratio within a range that does not reduce the effect of the present invention.

(Printing ink)
The printing ink of the present invention can be obtained by subjecting the raw materials having the following composition to kneading by a known method and adjusting the coarse particles in the ink to have a particle size of 5 μm or less to obtain the desired ink. .

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. In the present invention, “%” represents “mass%”.

The method for producing the printing ink may be a known and commonly used method, and will be described below with specific examples.
(Example 1) Rosin-modified phenolic resin Hiros OR-480 (manufactured by Seiko PMC Co., Ltd.) 30%, soybean oil (manufactured by Nisshin Oilio Co., Ltd.) 24%, petroleum resin (manufactured by Tosoh Co., Ltd.) Petcoal 120 10 And 35% of AF Solvent No. 7 (JX Nippon Oil & Energy Co., Ltd.) are heated to dissolve and transesterify, and then ALCH (aluminum ethyl acetoacetate diisopropylate, Kawaken Fine Chemical Co., Ltd.) (Product made) A varnish was prepared by adding 1% and performing chelation to obtain a tolerance of 10 (mL / 3 g) in advance.
Next, 13% organic pigment FASTOGENBLUE FA5375 (manufactured by DIC Corporation), 12% calcium carbonate white glaze TDD (manufactured by Shiroishi Kogyo Co., Ltd., primary particle size 80 nm) by a three roll mill, 70% of the above varnish, wax compound An ink was prepared by charging 1% (manufactured by DIC Corporation) and 4% AF Solvent No. 7 (manufactured by JX Nippon Oil & Energy Corporation).

  In the same manner, inks of Examples 2 to 3 and Reference Example were prepared with the formulation shown in Table 1.

(Comparative Example 1)
In the same manner as in Example 1, the inks of Comparative Examples 1 to 8 were prepared with the formulations shown in Tables 2 and 3.

The inks of Examples and Comparative Examples prepared above were evaluated by the following evaluation methods.
<Evaluation of ink>
(Heat set property)
The heat set property was evaluated using a color developed product obtained by developing an ink amount of 0.125 mL on OK top coat paper using an RI tester. Immediately after the color development, a conveyor type dryer maintained at 200 ° C. was passed for 5 seconds. Thereafter, the degree of stickiness of the developed color was evaluated by comparison with the conventional ink of the reference example. Evaluation was made sticky → heat set property “inferior”, non-sticky → heat set property “excellent”, or “standard”.

(Evaluation of onboard stability)
Each of the printing ink compositions of Examples and Comparative Examples was printed using an incometer (manufactured by Toyo Seiki Seisakusho) under the conditions of an ink amount of 0.5 cc, a room temperature of 25 ° C., a roller temperature of 32 ° C., and a rotation speed of 1200 rpm. The time until the film began to peel was measured and relative evaluation was performed. It can be evaluated that the longer the time until peeling, the better the on-machine stability.
The conventional ink of the reference example was set to “standard”, and “inferior”, “excellent”, or “standard” was evaluated.

(Emulsification suitability)
A printing ink emulsification suitability test was performed using a lithotronic emulsification tester (manufactured by Novocontrol) under the following conditions.
Ink amount 25 g, temperature 40 ° C., water addition rate 2 mL / min, stirring speed 1200 rpm, conditioning 5 minutes before starting water addition, stirring blade and cup gap 1 mm.

  The lithotronic emulsification tester puts a certain amount of ink into a measuring cup and stirs the stirring blade with the stirring blade of the same device while adding the torque to the stirring blade over time. It is a device to measure. As water is added to the ink in the cup, the torque increases as the amount of added water increases. There are cases where the torque increases monotonously and reaches a maximum value and decreases at once, and there is a case where the torque has a maximum value and then gradually decreases.In either case, the added water is not mixed with the ink and the torque is reduced. The emulsification rate at the time when it decreases or becomes unstable is defined as the maximum emulsification rate. The maximum emulsification rate is shown by the following formula.

  The maximum emulsification rate is preferably 20% or more and 100% or less, more preferably 30% or more and 80% or less. Among these ranges, a value close to 30% is particularly preferable because of excellent emulsification ability. When the maximum emulsification rate is 100% or more, it is in an over-emulsified state, and when it is less than 20%, excessive dampening water may remain on the plate or stains may occur, which is not preferable.

The conventional ink of the reference example was set to “standard”, and “inferior”, “excellent”, or “standard” was evaluated.
The above results are shown in Tables 1 to 3.

* ×: Cannot be adjusted as ink and cannot be evaluated.

  From the results of the examples and comparative examples described above, it is clear that inks that do not satisfy the requirements of the present invention cannot solve the problems of the invention, and that the problems can be solved only with the structure of the present invention.

  The printing ink of the present invention can be used as an ink for offset lithographic printing.

Claims (3)

Rosin-modified phenolic resin varnish, vegetable oil, calcium carbonate, and a heatset printing ink containing an organic solvent,
(1) The tolerance value of rosin-modified phenolic resin varnish is 5 to 50 (mL / 3 g),
(2) The content of vegetable oil is 15 to 30% by mass,
(3) The content of calcium carbonate is 8 to 25% by mass,
(4) The content of the organic solvent is 15 to 40% by mass,
An offset lithographic printing ink characterized by The heat-set printing ink according to claim 1, wherein the primary particle diameter of calcium carbonate is 30 to 150 nm. A printed matter printed using the heat-set printing ink according to claim 1.