JP6990077B2 - Plasma-curable offset printing ink composition, and a method for manufacturing and printing printed matter using the composition. - Google Patents

Description

The present invention relates to an ink composition for plasma curable offset printing, and a method for producing and printing a printed matter using the same.

Offset printing is a printing method that utilizes the property that an oil-based offset printing ink composition (hereinafter, also simply referred to as an ink composition) repels water, and is a letterpress printing method that uses a printing plate having irregularities. Unlike this, it is a printing method characterized by using a printing plate having no unevenness. This printing plate includes a lipophilic image portion and a hydrophilic non-image portion instead of unevenness, and at the time of printing, the non-image portion is first wetted with dampening water supplied to the printing plate. Then, when the oil-based ink composition is supplied to the printing plate, the ink composition is moistened with dampening water and does not repel and adhere to the moist non-image portion, and is lipophilic. It adheres only to the image part. In this way, an image of the ink composition is formed on the surface of the printing plate, and the image of the ink composition is sequentially transferred to the blanket and the base material (in many cases, paper is selected as the base material) for printing. Is done.

Further, in addition to the offset printing using dampening water as described above, a waterless offset printing method using a printing plate in which a non-image portion is formed of a silicone resin has also been put into practical use. In this printing method, the dampening water does not repel the ink composition to form a non-image area, but the silicone resin repels the ink composition to form a non-image area. Apart from these points, waterless offset printing is also a printing method common to offset printing using dampening water. Therefore, in the present specification, the term "offset printing" is used as a concept including not only the printing method using dampening water but also the waterless printing method.

By the way, in the printed matter obtained by offset printing, if the ink composition adhering to the surface of the printed matter is not sufficiently dried, set-off may occur when the printed matter is stacked or the printed matter may be touched with a finger. Since ink adheres to the product, it cannot be sent to a later process or distributed as a commercial product. Therefore, after performing offset printing, a step of drying the ink composition adhering to the surface of the printed matter and fixing it on the surface of the base material is required. Here, as a drying method of the ink composition in the offset printing method, four types such as oxidative polymerization, evaporation, permeation and photopolymerization are well known depending on the type of the ink composition used.

Of these methods, the method of drying the ink composition by permeation is a method of permeating the oil component contained in the ink composition adhering to the surface of the printed matter into the inside of the printed matter to obtain surface drying, and the speed is relatively high. A dry state can be obtained. However, in this drying method, the ink composition tends to spread on the surface of the printed matter and the halftone dots tend to thicken. In addition, the method of drying the printing ink composition by evaporation also has a concern about the environmental load due to the release of VOC (volatile organic compound) into the atmosphere.

From this point of view, when obtaining a printed matter that requires high cosmeticity, a method of drying the ink composition by oxidative polymerization tends to be adopted. In the ink composition used in this drying method, unsaturated oils having a high iodine value such as flaxseed oil are used as oil components, and these unsaturated oils are oxidatively polymerized by oxygen contained in the air to become sticky. Form a dry (ie, dry) film. According to the method of drying the ink composition by oxidative polymerization, there is no process of infiltrating the oil component into the printed matter or releasing VOC into the atmosphere, so that the printed matter having high cosmeticity has a low environmental load. Can be obtained at. However, since the chemical reaction for oxidatively polymerizing unsaturated oil takes a relatively long time, there is a possibility that problems may occur due to poor drying of printed matter.

Against the above background, printing by the photopolymerization drying method, in which the printed matter after printing is irradiated with ultraviolet rays to obtain drying, has been actively performed in recent years. The ink composition used in this drying method contains a monomer or oligomer having an ethylenically unsaturated bond and a photopolymerization initiator that generates a radical by irradiation with active energy rays such as ultraviolet rays, and after printing. By irradiating with active energy rays, these instantly polymerize to form a non-greasy (ie, dry) film. In recent years, ink compositions that employ such a drying method have been proposed to have various compositions (see, for example, Patent Documents 1, 2, and the like). Further, a method of printing using an ink composition containing a specific component and irradiating the obtained printed matter with plasma to cure and fix the ink composition existing on the surface of the printed matter has also been proposed. (See, for example, Patent Document 3).

Japanese Unexamined Patent Publication No. 2012-102217 Japanese Patent No. 4649952 Japanese Patent No. 5118823

The method of irradiating the printed matter after printing with plasma to dry (that is, fix) the ink composition is a new method, and compared to the method of drying by irradiating with ultraviolet rays, unreacted monomers, decomposition products of photopolymerization initiators, etc. Is excellent in that it can be suppressed from being released from the printed matter. Drying of the ink composition in this method is realized by reacting the components in the ink composition with the energy of plasma to increase the molecular weight. The plasma used at this time is classified into a direct type and a remote type according to the generation method. Plasma is formed by ionizing the gas existing in the discharge space by discharging it between the electrodes, but the direct type is a method in which the plasma irradiation target is directly sent into this discharge space to perform plasma irradiation. The remote type is a method in which the plasma raw material gas is circulated from the outside to the inside of the discharge space, and the plasma-generated gas is circulated outside the discharge space to irradiate the plasma irradiation target.

The plasma irradiation method used in the invention described in Patent Document 3 is the former (direct type), and is advantageous in terms of drying the ink composition because it can irradiate the irradiation target with highly reactive plasma immediately after generation. However, in the case of the direct type, there is a possibility that the printing substrate such as paper will be damaged by passing through the discharge space, and considering that the inlet and outlet of the discharge space isolated from the outside are narrow, it is basic. The base material may be clogged due to vertical fluttering in the material transport process. In the latter remote type, such a problem does not occur, but the ink composition on the substrate is dried due to the influence of the decrease in plasma temperature due to the movement of plasma gas from the discharge space and the diffusion of plasma gas. May be inadequate.

The present invention has been made in view of the above circumstances, and the present invention can obtain a sufficiently dry state even when plasma generated by a remote type plasma generator is used. It is an object of the present invention to provide an ink composition for plasma curable offset printing having high reactivity, and a method for producing and printing a printed matter using the same.

As a result of diligent studies to solve the above problems, the present inventors have made a conjugated fatty acid as at least a part of this oil component in an offset printing ink composition containing a pigment component, a binder resin and an oil component. By using a specific oil component consisting of at least one selected from the group consisting of triglycerides having an acyl group having a heavy bond, α-olefin compounds, and monoalkyl ester compounds of fatty acids, the polymerization reaction at the time of plasma irradiation can be carried out. It has been found that the present invention is remarkably improved, and the present invention has been completed. Specifically, the present invention provides the following.

(1) The present invention is a triglyceride containing a pigment component, a binder resin and an oil component, and having an acyl group having a conjugated double bond as at least a part of the oil component, and the acyl group constituting the triglyceride. Consists of a conjugated double-bonded acyl group of 30% or more , dehydrated castor oil, α-olefin compound having 16 to 18 carbon atoms , and a monoalkyl ester compound of soybean oil, castor oil, flaxseed oil or tung oil fatty acid. A remote plasma curable offset printing ink composition comprising a specific oil component consisting of at least one selected from the group.

(2) The present invention is the remote plasma curable offset printing ink composition according to item (1), wherein the triglyceride is tung oil, vine oil or dehydrated castor oil.

(3) The present invention also comprises the remote plasma curable offset printing ink composition according to item (1) or (2), wherein the content of the specified oil component is 10% by mass or more with respect to the entire composition. It is a thing.

(4) Further, the present invention is a triglyceride having an acyl group having a conjugated double bond as the specific oil component, and 50% or more of the acyl groups constituting the triglyceride are conjugated double bond acyl groups. Item 3. The remote plasma curable offset printing ink according to any one of Items (1) to (3), which comprises an α-olefin compound having 16 to 18 carbon atoms and a monoalkyl ester compound of a soybean oil fatty acid. It is a composition.

(5) The present invention comprises a printing step of printing on a substrate using the remote plasma curable offset printing ink composition according to any one of (1) to (4), and the above-mentioned printing step. The plasma is generated by a remote type plasma generator, including a plasma irradiation step of irradiating the substrate that has passed through the process with plasma to fix the ink composition existing on the surface of the substrate by curing. It is also a method for producing printed matter, which is characterized by being present.

( 6 ) The present invention is the method for producing a printed matter according to item (5) , wherein the plasma is generated by passing air or oxygen gas between the electrodes being discharged.

( 7 ) The present invention prints on a substrate using the remote plasma curable offset printing ink composition according to any one of (1) to (4), and then prints the above. It is characterized in that the ink composition is fixed on a substrate by irradiating the surface of the ink composition with plasma, and it is also a printing method in which the plasma is generated by a remote type plasma generator .

According to the present invention, a plasma curing offset with high reactivity to plasma can be obtained even when plasma generated by a remote plasma generator is used. A printing ink composition, and a method for producing and printing a printed matter using the same are provided.

Hereinafter, an embodiment of the plasma curable offset printing ink composition of the present invention, an embodiment of a method for producing a printed matter, and an embodiment of a printing method will be described. The present invention is not limited to the following embodiments and embodiments, and can be carried out with appropriate modifications within the scope of the present invention.

<Plasma curable offset printing ink composition>
The plasma-curable offset printing ink composition of the present invention (as described above, abbreviated as an ink composition as appropriate) is an ink composition applied to offset printing, and is irradiated with plasma which is an ionized gas. Has the ability to receive and cure. More specifically, from oil components having unsaturated bonds contained in the ink composition, particularly triglycerides having an acyl group having a conjugated double bond, α-olefin compounds, and monoalkyl ester compounds of fatty acids. A specific oil component consisting of at least one selected from the group is polymerized when irradiated with plasma to increase the molecular weight, and the film of the ink composition is cured. Therefore, when the ink composition sticky on the surface of the printed matter is irradiated with plasma immediately after printing, the ink composition is instantly cured and becomes a dry (tack-free) state. The ink composition of the present invention is applied not only to offset printing using dampening water, but also to waterless offset printing using dampening water.

The plasma used for curing the ink composition of the present invention may be any one that polymerizes a component such as an oil component described later, particularly a specific oil component described later. Plasma is generated by ionizing a gas existing in an electric field (that is, a gas existing between electrodes to which a voltage is applied), and has a high energy capable of causing a chemical reaction. Generally, plasma is generated by passing a high-frequency current between electrodes separated from each other, and the generator thereof is classified into a direct type and a remote type according to the plasma generation form. In the direct type, plasma irradiation is performed by passing a processing target, that is, a printed base material, between electrodes to which a voltage is applied (that is, in a discharge space). In this case, high reactivity is expected due to the plasma immediately after generation, but there is concern about damage to the base material due to electric discharge or high temperature plasma. On the other hand, in the remote type, plasma generated in a place different from the processing target is carried on the plasma gas air flow and transported to the processing target for plasma irradiation. In this case, the damage to the base material is suppressed, but the temperature of the plasma decreases during the transportation of the plasma, and the reactivity of the plasma decreases as the plasma diffuses. Since the ink composition of the present invention exhibits high reactivity when irradiated with plasma, it exhibits good curability not only with plasma generated by the direct type but also with plasma generated by the remote type.

In the present invention, examples of the gas used to generate plasma include air, oxygen gas, carbon dioxide gas, nitrogen gas, argon gas, and water vapor, but the gas is not particularly limited. Among these, air or oxygen gas is preferably mentioned.

The ink composition of the present invention contains a pigment component, a binder resin and an oil component, and as at least a part of the oil component, a triglyceride having an acyl group having a conjugated double bond, an α-olefin compound, and a fatty acid mono. It is characterized by containing a specific oil component consisting of at least one selected from the group consisting of alkyl ester compounds. Hereinafter, each component will be described.

[Pigment component]
Examples of the pigment component include colored pigments and extender pigments. The coloring pigment is a component for imparting coloring power to the ink composition, and is an essential component for printing character information, images, and the like. In the present invention, a white pigment having no color is also treated as a coloring pigment. The extender pigment has no coloring power, but is used for adjusting properties such as fluidity and viscoelasticity of the ink composition. In the ink composition of the present invention, at least one of the above colored pigment and the extender pigment may be included as a pigment component. For example, when the ink composition does not contain a coloring pigment but contains an extender pigment, the ink composition can be used as a transparent varnish or a medium.

The coloring pigments include yellow pigments such as disazo yellow (pigment yellow 12, pigment yellow 13, pigment yellow 17, pigment yellow 1) and Hansa yellow, magenta pigments such as brilliant carmine 6B, lake red C, and watching red, and phthalocyanine blue. , Cyan pigments such as phthalocyanine green and alkaline blue, black pigments such as carbon black, and white pigments such as titanium oxide and zinc oxide are exemplified.

The amount of the coloring pigment added is exemplified, but is not particularly limited to about 8 to 30% by mass with respect to the entire ink composition. The yellow pigment is used for the yellow ink composition, the magenta pigment is used for the magenta ink composition, the cyan pigment is used for the cyan ink composition, and the black pigment is used for the black ink composition. At the time of preparation, it is also possible to use a pigment of another color in combination as a complementary color, or to add an ink composition of another color.

Examples of the extender pigment include clay, talc, kaolinite (kaolin), barium sulfate, calcium carbonate, silicon oxide, bentonite and the like. The amount of the extender pigment added is exemplified, but is not particularly limited to about 0 to 33% by mass with respect to the entire ink composition.

[Binder resin]
The binder resin (hereinafter, also simply referred to as “resin”) is a component that functions as a binder for fixing the pigment component on the surface of the printing paper, and is used for dispersing the pigment component in the ink composition. It is also an ingredient that can be used. Examples of such resins include those usually used in the field of ink compositions without particular limitation, such as rosin-modified phenolic resin, rosin-modified maleic acid resin, rosin-modified alkyd resin, rosin-modified petroleum resin, and rosin ester. Examples thereof include resins, petroleum resin-modified phenolic resins, acrylic-modified phenolic resins, alkyd resins, vegetable oil-modified alkyd resins, and petroleum resins. The weight average molecular weight of these resins is preferably about 3000 to 300,000.

Among these resins, from the viewpoint of pigment dispersibility, print quality and stable printability over a long period of time, the group consists of rosin-modified phenolic resins and rosin-modified maleic acid resins having a weight average molecular weight of 10,000 to 150,000. It is preferable to use at least one selected. Further, in order to improve the dispersibility of the pigment component, it is also preferable to use these resins in combination with an alkyd resin. In this case, it is preferable to use about 3 to 10 parts by mass of the alkyd resin with respect to 100 parts by mass of the total of the rosin-modified phenol resin and the rosin-modified maleic acid resin. The amount of the resin added is preferably about 10 to 35% with respect to the entire ink composition.

The resin is melted by being heated together with an oil component described later, and is used as a varnish. When preparing the varnish, a gelling agent such as a metal chelate compound or a metal soap may be added to the dissolved varnish obtained by dissolving the resin to obtain a gelled varnish. It is preferable to prepare a gelled varnish from a resin and use it for preparing an ink composition because an appropriate viscoelasticity can be imparted to the ink composition.

[Oil component]
The oil component is used to dissolve the resin to form a varnish or to adjust the viscosity of the ink composition. The ink composition of the present invention is characterized by containing, as at least a part of this oil component, a specific oil component described below. By adding the specific oil component to the ink composition, the curability of the ink composition when subjected to plasma irradiation is significantly improved.

The specific oil component is selected from at least one selected from the group consisting of (1) a triglyceride having an acyl group having a conjugated double bond, (2) an α-olefin compound, and (3) a monoalkyl ester compound of a fatty acid. Become. The ink composition of the present invention may contain only one system of the three specific oil components shown in the above (1) to (3), or may contain a plurality of systems. The ink composition of the present invention is at least one kind in the compound group shown in (1), at least one kind in the compound group shown in (2), and at least one kind in the compound group shown in (3). It is preferable to include all of the above.

A triglyceride having an acyl group having a conjugated double bond is a triglyceride which is an ester of glycerin and three molecules of fatty acid, and at least one of the above three molecules of fatty acid has a conjugated double bond. A fatty acid having a conjugated double bond becomes an acyl group having a conjugated double bond by forming an ester with glycerin.

The ink composition is curable at the time of plasma irradiation by containing a triglyceride having an acyl group having a conjugated double bond (hereinafter, also referred to as a conjugated double bond acyl group) as a part of its constituent components. That is, the increase in the weight due to the polymerization reaction that occurs when the product is irradiated with plasma is promoted. In general, triglycerides containing a large amount of unsaturated bonds have a high iodine value, which is a quantitative index of unsaturated bonds, and are likely to cause polymerization due to an oxidation reaction. However, for example, flaxseed oil, which exhibits a high iodine value but does not have a conjugated double-bonding acyl group, is not highly polymerizable when irradiated with plasma. On the other hand, tung oil, which has a lower iodine value than linseed oil but is rich in conjugated double-bonding acyl groups, exhibits high polymerizability when exposed to plasma irradiation. From these facts, it is suggested that the polymerizable property is enhanced by causing the Diels-Alder reaction during plasma irradiation. From this point of view, the conjugated double bond acyl group preferably has a cis-type conjugated double bond. Further, in the triglyceride having a conjugated double-bonding acyl group, it is preferable that 30% or more of the acyl groups constituting the triglyceride is a conjugated double-bonding acyl group, and 50% or more is a conjugated double-bonding acyl group. It is preferably an acyl group. Examples of such triglycerides include tung oil (containing about 80% of eleostearic acid, which is a conjugated double-bonding acyl group), turret oil (also containing about 60%), and dehydrated castor oil (conjugated di). A double-bonding acyl group is contained in an amount of about 30% by mass.) And the like.

The content of the triglyceride having a conjugated double-bonding acyl group in the ink composition is preferably about 10 to 60% by mass, more preferably about 10 to 50% by mass, and 10 to 30% by mass. The degree is more preferably mentioned.

The α-olefin compound is a chain aliphatic hydrocarbon having a double bond at the terminal and may have a branch. It is available in the petrochemical industry as a synthetic oil derived from ethylene, and Idemitsu Kosan Co., Ltd.'s Linearlen (registered trademark) is exemplified as such a product. Linearene (registered trademark) manufactured by Idemitsu Kosan Co., Ltd. is an n-paraffin (α-olefin) having a double bond at the terminal, and the grade is divided according to the number of carbon atoms. As the α-olefin, those having a boiling point of 200 ° C. or higher and having 12 or more carbon atoms are preferably used, those having 14 to 20 carbon atoms are more preferably used, and those having 16 to 18 carbon atoms are more preferably used. Will be. By containing the α-olefin in the ink composition, the polymerizable property of the ink composition when subjected to plasma irradiation is improved.

The content of the α-olefin in the ink composition is preferably about 5 to 30% by mass, more preferably about 5 to 20% by mass, and even more preferably about 5 to 15% by mass.

The fatty acid monoalkyl ester compound is a fatty acid monoalkyl ester compound obtained by transesterifying vegetable oil or animal oil which is a triglyceride. Examples of such fatty acids include fatty acids derived from dry oils such as soybean oil, cottonseed oil, flaxseed oil, safflower oil, tung oil, tall oil, dehydrated castor oil and canola oil, and semi-drying oils. As the fatty acid constituting the fatty acid monoalkyl ester compound, an unsaturated fatty acid having 16 to 20 carbon atoms is preferably exemplified, and examples of such an unsaturated fatty acid include oleic acid, linoleic acid, linolenic acid, and eleostearic acid. Is preferably exemplified. As the alkyl group constituting the fatty acid monoalkyl ester compound, an alkyl group having 1 to 10 carbon atoms is preferably exemplified, and more specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, and the like. A tert-butyl group, a 2-ethylhexyl group and the like are preferably exemplified. Among these fatty acid monoalkyl ester compounds, soybean oil monoalkyl ester and tung oil monoalkyl ester are preferably mentioned. By replacing the vegetable oil contained in the ink composition with a monoalkyl ester of fatty acid, the polymerizable property of the ink composition when subjected to plasma irradiation is improved.

The content of the monoalkyl ester compound of the fatty acid in the ink composition is preferably about 10 to 60% by mass, more preferably about 10 to 50% by mass, and even more preferably about 10 to 30% by mass. Be done.

The content of the specific oil component in the ink composition is preferably 10% by mass or more, more preferably 20% by mass or more, further preferably 30% by mass or more, further preferably 40% by mass or more, and further preferably 45% by mass or more. preferable. The upper limit of the content of the specific oil component in the ink composition may be appropriately determined in consideration of the viscosity and the like required for the ink composition, but may be about 60% by mass.

The ink composition of the present invention may contain an oil component in addition to the above-mentioned specific oil component. Examples of such oil components include vegetable oils and / or mineral oils, and those that have been used for preparing ink compositions can be used without particular limitation.

Examples of vegetable oils include drying oils such as soybean oil, cottonseed oil, flaxseed oil, safflower oil, tall oil, and canola oil, and semi-drying oils. These vegetable oils can be used alone or in combination of two or more. As the content of vegetable oil in the ink composition, about 0 to 60% by mass can be exemplified with respect to the entire ink composition.

Examples of the mineral oil include a light mineral oil called a solvent component and a heavy mineral oil which is a lubricating oil. Examples of light mineral oils include non-aromatic petroleum solvents having a boiling point of 160 ° C. or higher, preferably 200 ° C. or higher. Examples of such non-aromatic petroleum solvents include No. 0 solvent, AF solvent No. 5, AF solvent No. 6, and AF solvent No. 7 manufactured by JX Nippon Oil Energy Co., Ltd. Examples of heavy mineral oils include various lubricating oils that have been classified as spindle oils, machine oils, dynamo oils, cylinder oils and the like. Among these, from the viewpoint of adapting to the OSHA standard and the EU standard in the United States, it is preferable that the content of the condensed polycyclic aromatic component is suppressed. Examples of such mineral oils include ink oil H8 and ink oil H35 (all trade names) manufactured by JX Nikko Nisseki Energy Co., Ltd., SNH8, SNH46, SNH220, and SNH540 manufactured by Sankyo Yuka Kogyo Co., Ltd. (Both are product names) and the like are exemplified.

A conventionally known method can be used in producing the ink composition of the present invention using each of the above components. As such a method, after mixing each of the above components, the pigment component is dispersed by kneading with a bead mill, a three-roll mill, or the like, and then an oil component or an additive (antioxidant, alcohol) is used as necessary. It can be exemplified that the viscosity is further adjusted by adding (kind, etc.) and stirring well.

In a normal ink composition, paraffin wax or PTFE wax is used for the purpose of suppressing scratches on printed matter, but the ink composition of the present invention does not use these waxes, that is, contains wax. The amount is preferably 0% by mass. This is because, according to the findings of the present inventors, when the ink composition contains wax, the curability when irradiated with plasma is lowered. Although the reason is not always clear, it is considered that the wax component contained in the ink composition floats on the surface of the film of the ink composition after printing, and the wax component thus lifted is the ink. It is considered that this is because it inhibits the intrusion of plasma into the film of the composition.

<Manufacturing method of printed matter>
A printing step of printing on a substrate using the ink composition of the present invention, and a plasma of irradiating the substrate through the printing step with plasma to fix the ink composition existing on the surface of the substrate by curing. A method for producing a printed matter, which comprises an irradiation step, is also one of the present inventions. Next, an embodiment of the method for producing a printed matter of the present invention will be described.

The printing step is a step of printing on a substrate using the ink composition of the present invention. Examples of the substrate on which printing is performed include paper and film. Further, as a printing means, offset printing can be mentioned, and as an example of such a printing method, sheet-fed printing, offset rotary printing, and the like can be mentioned. When performing offset printing, waterless offset printing may be adopted in addition to normal offset printing using dampening water. An image of the undried ink composition is formed on the base material that has undergone the printing step, and the base material is subjected to the plasma irradiation step.

In the plasma irradiation step, the substrate that has undergone the printing step is irradiated with plasma to cure the ink composition existing on the surface of the substrate, thereby fixing the ink composition. The plasma used at this time may be one generated from a direct type plasma generator or one generated from a remote type plasma generator, but the ink composition of the present invention is used for plasma irradiation. Since it is highly reactive, it is possible to sufficiently cure even plasma generated from a remote plasma generator. Therefore, from the viewpoint of suppressing damage to the base material and suppressing clogging of the base material due to vertical fluttering that occurs when the base material is transported, in this step, it is generated from a remote plasma generator. It is preferable to use plasma.

When the plasma generated from the remote plasma generator is used for curing the ink composition, the plasma emission ports are preferably arranged in a line along the width direction of the base material. Such outlets may have a plurality of point-shaped outlets arranged in a row along the width direction of the base material, or linear discharge ports arranged along the width direction of the base material. May be.

Examples of the reaction gas used for generating plasma include air, oxygen gas, carbon dioxide gas, nitrogen gas, argon gas, water vapor and the like, but are not particularly limited. Among these, air or oxygen gas is preferably mentioned. The reaction gas is converted into plasma by passing between electrodes connected to a high-frequency power source and in a discharged state, and is discharged from the discharge port toward the surface of the base material.

<Printing method>
Printing is characterized in that printing is performed on a substrate using the ink composition of the present invention, and then the surface of the printed ink composition is irradiated with plasma to fix the ink composition on the substrate. The method is also one of the present inventions. Since this is the same as the method for producing the printed matter of the present invention, the description thereof is omitted here.

Hereinafter, the ink composition of the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the following description, unless otherwise specified, "%" means "% by mass" and "part" means "part by mass".

[Preparation of varnish 1]
42 parts of rosin-modified phenolic resin (manufactured by Harima Kasei Co., Ltd.) with a weight average molecular weight of 100,000 and 57.5 parts of butyl ester of soybean oil fatty acid are charged in a four-necked flask equipped with a cooling tube, a thermometer and a stirrer. After that, the temperature was raised to 210 ° C. and the resin was melted by maintaining the same temperature for 40 minutes, and then 0.5 part of aluminum ethylacetacetate diisopropylate (manufactured by Kawaken Fine Chemical Co., Ltd., ALCH) was charged, and then 0.5 part was charged. The varnish 1 was obtained by heating and holding at 170 ° C. for 50 minutes. Varnish 1 contains 57.5% of butyl ester of soybean oil fatty acid, which is a specific oil component, as an oil component.

[Preparation of varnish 2]
42 parts of rosin-modified phenolic resin (manufactured by Harima Kasei Co., Ltd.) with a weight average molecular weight of 100,000 and 57.5 parts of tung oil were placed in a four-necked flask equipped with a cooling tube, a thermometer and a stirrer, and then heated to 210 ° C. After the resin is melted by raising the temperature and maintaining the same temperature for 40 minutes, 0.5 part of aluminum ethylacetate acetate diisopropyrate (ALCH manufactured by Kawaken Fine Chemical Co., Ltd.) is charged, and then at 170 ° C. for 50 minutes. The mixture was heated and held to obtain varnish 2. Varnish 2 contains 57.5% of tung oil, which is a specific oil component, as an oil component.

[Preparation of varnish 3]
42 parts of rosin-modified phenolic resin (manufactured by Harima Kasei Co., Ltd.) with a weight average molecular weight of 100,000 and 57.5 parts of soybean oil were placed in a four-necked flask equipped with a cooling tube, a thermometer and a stirrer, and then 210 ° C. After the resin was melted by raising the temperature to 50 and maintaining the same temperature for 40 minutes, 0.5 part of aluminum ethylacetate acetate diisopropylate (ALCH, manufactured by Kawaken Fine Chemical Co., Ltd.) was charged, and then 50 at 170 ° C. The mixture was heated and held for a minute to obtain varnish 3. Varnish 3 contains 57.5% soybean oil as an oil component. Soybean oil is not a specific oil component in the present invention.

[Preparation of varnish 4]
42 parts of rosin-modified phenolic resin (manufactured by Harima Kasei Co., Ltd.) with a weight average molecular weight of 100,000 and 57.5 parts of linseed oil were placed in a four-necked flask equipped with a cooling tube, a thermometer and a stirrer, and then 210 ° C. After the resin was melted by raising the temperature to 50 and maintaining the same temperature for 40 minutes, 0.5 part of aluminum ethylacetate acetate diisopropylate (ALCH, manufactured by Kawaken Fine Chemical Co., Ltd.) was charged, and then 50 at 170 ° C. The varnish 4 was obtained by heating and holding for 1 minute. Varnish 4 contains 57.5% flaxseed oil as an oil component. Linseed oil is not a specific oil component in the present invention.

[Preparation of ink composition]
Various materials were mixed according to the formulations shown in Tables 1 and 2, and the meat was kneaded using three rolls to prepare ink compositions of Examples 1 to 8 and Comparative Examples 1 and 2. The blending amount of each component shown in Tables 1 and 2 is by mass. In Tables 1 and 2, the "color pigment" is the phthalocyanine of the coloring pigment, the "α-olefin" is the linearene 168 manufactured by Idemitsu Kosan Co., Ltd., and the "fatty acid ester" is the butyl ester of the soybean oil fatty acid. "Wax" is a polyethylene wax. The α-olefins shown in Tables 1 and 2 are specific oil components in the present invention. Further, in the lower part of Tables 1 and 2, the total content (mass%) of each oil component in the ink composition is shown. Among these oil components, fatty acid ester, tung oil and α-olefin correspond to the specific oil component in the present invention, and soybean oil and linseed oil do not correspond to the specific oil component in the present invention.

[Evaluation of curability]
The curability of each of the ink compositions of Examples 1 to 8 and Comparative Examples 1 and 2 when irradiated with plasma was evaluated. First, take 0.1 cc of a sample of the ink composition and use a RI color developer (2-split roll, manufactured by Akira Seisakusho Co., Ltd.) to make a PP (polypropylene) film (manufactured by Sekisui Molding Industry Co., Ltd., product name: Polysame PC-8162). ), And plasma was applied to the developed surface using a damage-free multi-gas plasma jet (remote type plasma generator) manufactured by Plasma Concept Tokyo Co., Ltd. At that time, the plasma gas was air (flow rate 5 L / min), the plasma irradiation diameter was 1 mm, and the irradiation distance was 3 mm. After irradiating with plasma for 5 seconds, the uncured ink composition was wiped off with absorbent cotton, and the diameter of the coating film cured in a circular shape was measured. The results are shown in the "Cure diameter" column of Tables 1 and 2. Plasma is more reactive toward the center of irradiation and less reactive toward the periphery. An ink composition having a larger curing diameter has a higher reactivity with plasma.

From the results in Tables 1 and 2, it can be seen that the ink composition containing the specific oil component in the present invention exhibits high curability with respect to plasma. That is, the ink composition of Example 2 containing tung oil, which is a triglyceride having an acyl group having a conjugated double bond, is the ink composition of Comparative Example 1 containing soybean oil, or linseed oil having a higher degree of unsaturation than tung oil. It can be seen that the curability is significantly higher than that of the ink composition of Comparative Example 2 containing oil. Further, it can be seen that the ink compositions of Examples 5 and 6 in which a part of the soybean oil or the flaxseed oil in the ink compositions of Comparative Examples 1 and 2 is replaced with α-olefin also have remarkably high curability. Further, in the ink composition of Example 1 in which the soybean oil contained in the ink composition of Comparative Example 1 was replaced with the fatty acid ester of soybean oil, improvement in curability was confirmed. From these results, it was confirmed that the ink composition containing the specific oil component in the present invention has high curability against plasma. The specific oil component in the present invention includes three lines of triglyceride having an acyl group having a conjugated double bond, an α-olefin compound, and a monoalkyl ester compound of a fatty acid, and all of these three lines are combined. By using it, it can be expected that higher curability can be obtained.

Claims (7)

Contains pigment component, binder resin and oil component
A triglyceride having an acyl group having a conjugated double bond as at least a part of the oil component, wherein 30% or more of the acyl groups constituting the triglyceride is a conjugated double bond acyl group, dehydrated soybean oil. It is characterized by containing a specific oil component consisting of at least one selected from the group consisting of oil, an α-olefin compound having 16 to 18 carbon atoms , and a monoalkyl ester compound of soybean oil, castor oil, flaxseed oil or tung oil fatty acid. Remote type plasma curable type offset printing ink composition. The remote plasma curable offset printing ink composition according to claim 1, wherein the triglyceride is tung oil, vine oil or dehydrated castor oil. The remote plasma curable offset printing ink composition according to claim 1 or 2, wherein the content of the specific oil component is 10% by mass or more with respect to the entire composition. As the specific oil component, a triglyceride having an acyl group having a conjugated double bond, wherein 50% or more of the acyl groups constituting the triglyceride is a conjugated double bond acyl group, and the number of carbon atoms is 16 to 18. The remote plasma curable offset printing ink composition according to any one of claims 1 to 3, which comprises the α-olefin compound of the above and a monoalkyl ester compound of a soybean oil fatty acid. A printing step of printing on a substrate using the remote plasma curable offset printing ink composition according to any one of claims 1 to 4, and a substrate subjected to the printing step are irradiated with plasma. A method for producing a printed matter, comprising a plasma irradiation step of fixing an ink composition existing on the surface of a substrate by curing , wherein the plasma is generated by a remote plasma generator . The method for producing a printed matter according to claim 5 , wherein the plasma is generated by passing air or oxygen gas between the electrodes being discharged. Printing is performed on a substrate using the remote plasma curable offset printing ink composition according to any one of claims 1 to 4, and then the surface of the printed ink composition is irradiated with plasma. A printing method characterized by fixing the ink composition to a substrate , wherein the plasma is generated by a remote plasma generator .