JP5155978B2 - Offset printing ink composition and printed matter - Google Patents

Description

  The present invention relates to an offset printing ink composition comprising a sebacic acid diester.

  Conventionally, petroleum solvents obtained from petroleum fractions have been used as solvents for offset printing inks. However, it has been pointed out that petroleum-based solvents deplete petroleum resources and deteriorate the working environment.

  The offset printing ink industry has been working to improve the global environment and working environment. Conventional ink solvents contained aromatic hydrocarbons as their constituent components, but nowadays, it is common to use AF (aromatic-free) solvents containing 1% or less of aromatic components based on paraffin and naphthene. Is. The AF solvent is excellent in low odor, low skin irritation and biodegradability, but the raw material is still the same petroleum as the conventional solvent.

  Therefore, in the offset printing ink, by replacing a part or all of the petroleum solvent that is the solvent of the ink with a specific fatty acid ester and / or aliphatic ether having a specific composition structure, It is disclosed that an offset ink having equivalent drying properties, printability, and printing effects can be obtained (see, for example, Patent Document 1 or 2). As described above, by using a naturally-derived component as a solvent, the solvent remaining in the printed matter has low skin irritation, and it is said that it does not cause discomfort to people with chemical sensitivity.

JP 2004-204202 A JP 2004-204203 A

  By the way, in said patent document, among the fatty acid esters, fatty acid esters derived from coconut oil or palm kernel oil are preferably used. However, in the cultivation of palm, which is a raw material for palm oil and palm kernel oil, in recent years, cultivation by plantation has been carried out on land that has been cut and cleared by virgin forest, and environmental destruction has become a problem.

  Further, when a solvent containing an aliphatic ether is used as a solvent, an unpleasant odor derived from the aliphatic ether deteriorates the working environment, and a slight odor remains on the printed matter.

  As described above, as a solvent component used in offset printing ink, there is a demand for a fatty acid ester derived from coconut oil or palm kernel oil, or a solvent component derived from a natural substance instead of an aliphatic ether solvent.

  The present invention has been made in order to solve the above-mentioned problems, and its purpose is to use a solvent component derived from a natural substance in place of an ester of a fatty acid derived from coconut oil or the like, or an aliphatic ether solvent. An object of the present invention is to provide an environment-friendly offset printing ink composition having an excellent printing effect and a printed matter using the environment-friendly offset printing ink composition.

  The inventors of the present invention have made extensive studies to solve the above problems. As a result, instead of fatty acid esters derived from coconut oil etc., sebacic acid obtained by alkali cleavage reaction of castor oil derived from castor sesame, which is a crop that can be cultivated in wasteland and dry land and has few problems of logging of primary forests, etc. It has been found that the above problems can be solved by using a diester as a solvent component, and the present invention has been completed. More specifically, the present invention provides the following.

The offset printing ink composition according to claim 1 includes 10 to 60% by mass of sebacic acid diester represented by the following general formula (1).
R ¹ OCO (CH ₂ ) ₈ COOR ² (1)
[In Formula (1), R ¹ and R ² are each a hydrocarbon group which may have a branch or an unsaturated bond, and the sum of the carbon atoms of R ¹ and R ² is from 4 18. ]

  The offset printing ink composition according to claim 2 is characterized in that the sebacic acid diester represented by the general formula (1) is di-2-ethylhexyl sebacate.

  The offset printing ink composition according to claim 3 is characterized in that it contains 20 to 55% by mass of sebacic acid diester represented by the general formula (1).

  The offset printing ink composition according to claim 4 is characterized in that it contains no solvent other than the sebacic acid diester represented by the general formula (1) and vegetable oil as a solvent component.

  The printed matter according to claim 5 is obtained by using the offset printing ink composition according to any one of claims 1 to 4.

  According to the present invention, by using a diester of sebacic acid obtained by an alkali cleavage reaction of castor oil, which is a natural fat and oil, as a solvent component of an offset printing ink composition, the printability / printing effect is improved by the conventional fatty acid ester and / or Alternatively, it is possible to obtain an environment-friendly ink that is comparable to offset printing inks that use aliphatic ethers as solvents.

  Further, by using an offset printing ink composition containing a diester of sebacic acid as a solvent component, it is difficult to swell an ink roller or a blanket made of a rubber material of a printing press, and a stable printed matter can be obtained.

  In the present invention, since a solvent containing a solvent component derived from a natural substance substantially free of aliphatic ether is used, an unpleasant odor of the solvent is reduced even at the ink production site, and the working environment is improved.

  Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the object of the present invention. . In addition, although description may be abbreviate | omitted suitably about the location where description overlaps, the summary of invention is not limited.

<Offset printing ink>
The offset printing ink of the present invention contains a varnish resin and a solvent.

[Resin for varnish]
The varnish resin used in the present invention is preferably a rosin ester resin, a rosin modified phenol resin, a maleic acid modified rosin ester resin, an alkyd resin, a rosin modified alkyd resin, a gilsonite resin, more preferably a rosin ester resin and / or. Examples include rosin-modified phenolic resins. The content of the varnish resin in the ink of the present invention is preferably 15 to 50% by mass, more preferably 20 to 40% by mass, and most preferably 25 to 35% by mass.

  The preferred rosin ester resin has a resin softening point H (° C.) of 120 ° C. ≦ H ≦ 210 ° C., a weight average molecular weight Mw of 20,000 ≦ Mw ≦ 300,000, preferably a softening point of 140 ° C. ≦ H ≦ The thing of 200 degreeC and the weight average molecular weight Mw 50,000 <= Mw <= 200,000 is mentioned. As the rosin ester resin, a modified rosin ester resin modified with introduction of polymerized rosin or a polybasic acid such as maleic anhydride or fumaric acid is preferably used.

  When the softening point H of the rosin ester resin is in the above range, the curability of the ink coating and the workability when preparing the ink varnish are further improved. Further, when the weight average molecular weight Mw of the rosin ester resin is within the above range, the fluidity and viscoelasticity of the ink are more excellent.

  The rosin-modified phenolic resin having a weight average molecular weight Mw of 10,000 ≦ Mw ≦ 300,000, preferably a weight average molecular weight Mw of 30,000 ≦ Mw ≦ 200,000 is used. When the weight average molecular weight Mw of the rosin-modified phenol resin is within the above range, the fluidity and viscoelasticity of the ink are more excellent.

  The ink varnish used in the ink of the present invention is prepared by blending the above varnish resin and solvent with a gelling agent, if necessary. As a method for preparing the ink varnish, for example, the above varnish resin, solvent, and vegetable oil are heated and stirred at 200 ° C. for 30 minutes in an inert gas atmosphere such as nitrogen, and then cooled to 150 ° C. Examples include a method of blending an agent and heating and stirring at 200 ° C. for 60 minutes.

  The content of the varnish resin in the ink varnish is preferably 20 to 60% by mass, more preferably 30 to 55% by mass.

[solvent]
The offset printing ink composition of the present invention contains a sebacic acid diester represented by the following general formula (1) as a solvent component.
R ¹ OCO (CH ₂ ) ₈ COOR ² (1)
[In Formula (1), R ¹ and R ² are each a hydrocarbon group which may have a branch or an unsaturated bond, and the sum of the carbon atoms of R ¹ and R ² is from 4 18. ]

The sebacic acid diester represented by the general formula (1) includes sebacic acid obtained by an alkali cleavage reaction of castor oil and an alcohol (R ¹ —OH) corresponding to the group R ¹ and the group R ² in the general formula (1). And R ² —OH) in the presence of an esterification catalyst.

In the present invention, the sebacic acid diester represented by the general formula (1) has a group R ¹ and a group R ² which are hydrocarbon groups which may have a branch or may have an unsaturated bond. , The sum of the number of carbon atoms of the group R ¹ and the group R ² is 4 to 18. Specific examples of suitable groups among such groups R ¹ and R ² include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, n-pentyl group, n- Saturated hydrocarbon groups such as hexyl group, n-heptyl group, n-octyl group, 2-ethylhexyl group, 1-methylheptyl group, n-nonyl group, n-decyl group, vinyl group, allyl group, 2-butenyl Group, 3-butenyl group, 3-hexenyl group, 2-octenyl group, 3-octenyl group, 5-octenyl group, 7-octenyl group, 2,4-octadienyl group, 2,5-octadienyl group, 2,7- Examples thereof include unsaturated hydrocarbon groups such as octadienyl group and 5,7-octadienyl group. Among these hydrocarbon groups, saturated hydrocarbon groups having 2 to 10 carbon atoms are more preferable because of excellent quality stability during storage.

  Among the sebacic acid diesters represented by the general formula (1), the resulting offset printing ink composition has an excellent balance of drying properties, printability, printing effects, and the like, so the group R has 8 carbon atoms. The saturated hydrocarbon group is more preferable, and di-2-ethylhexyl sebacate is most preferably used.

  Moreover, the sebacic acid diester represented by General formula (1) can be used 1 type or in combination of multiple types.

  By using the sebacic acid diester represented by the general formula (1) as a solvent, the skin irritation is low as compared with the case of using a petroleum-derived solvent, and it is a chemical substance as much as a conventional palm oil-derived solvent. An offset printing ink can be prepared that does not cause discomfort to sensitive people.

Ink rollers and blankets used in ordinary offset printing presses are made of rubber. For example, ABS resin etc. are mentioned. Such a rubber material absorbs a solvent and easily swells. Conventionally, among fatty acid esters derived from natural fats and oils such as coconut oil, those having a relatively low molecular weight tend to swell the rubber parts, and are represented by the general formula (1). As for the diester of sebacic acid, for example, when the sum of the number of carbon atoms of the group R ¹ and group R ² constituting the ester is as short as 2 to 3, such as dimethyl sebacic acid, the rubber component is swollen. There is an easy problem.

  However, by using the sebacic acid diester represented by the general formula (1) as a solvent, the rubber material does not swell compared with esters of fatty acids derived from natural oils and fats such as coconut oil. The printing effect can be obtained as an environmentally friendly ink that is comparable to the offset printing ink using conventional fatty acid ester and / or aliphatic ether as a solvent.

  The offset printing ink composition of the present invention contains 10 to 60% by mass of sebacic acid diester represented by the general formula (1), more preferably 20 to 55% by mass, and most preferably 20%. To 50% by mass. When there is too much content of the sebacic-acid diester represented by General formula (1), there exists a tendency for the on-machine stability and drying property of an offset printing ink composition to be inferior.

  The offset printing ink composition of the present invention may further contain vegetable oil as a solvent.

  Examples of the vegetable oil 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, and dryness such as linseed oil, eno oil and gill oil. Oils, preferably semi-drying oils and / or drying oils. Of these, soybean oil and linseed oil are particularly preferred.

  When vegetable oil is used as the solvent component, the content of vegetable oil in the offset printing ink is preferably 40% by mass or less, more preferably 35 to 5% by mass, and 30 to 10% by mass. Most preferred.

  As long as the content of the sebacic acid diester represented by the general formula (1) in the offset printing ink composition satisfies a predetermined amount, the solvent used for the preparation of the varnish is within a range that does not impair the object of the present invention. Other solvents of sebacic acid diester can also be used. Examples of other solvents of sebacic acid diester include, for example, fatty acid esters and aliphatic ethers.

  Specific examples of fatty acid esters that can be used with the sebacic acid diester represented by the general formula (1) include capric acid, lauric acid, myristic acid, palmitic acid, myristoleic acid, palmitoleic acid, stearic acid, oleic acid, Examples of fatty ethers such as linoleic acid and linolenic acid include methyl ester, ethyl ester, n-propyl ester, isopropyl ester, n-butyl ester, and isobutyl ester. Specific examples of aliphatic ethers include di-n-octyl. Examples thereof include ether, dinonyl ether, diheptyl ether, dihexyl ether, nonyl hexyl ether, nonyl heptyl ether, nonyl octyl ether and the like.

  The offset printing ink composition of the present invention does not contain a solvent other than the sebacic acid diester represented by the general formula (1) and vegetable oil because of the swelling problem of the rubber material and the problem of odor. Is particularly preferred.

[Other ingredients]
The ink varnish used for the offset printing ink of the present invention is prepared by blending the above varnish resin and solvent with a gelling agent as required.

  As the gelling agent, known ones can be used. For example, aluminum ethyl acetate diisopropylate, aluminum isopropylate, aluminum stearate, ethyl acetoacetate aluminum diisopropylate, aluminum diisopropoxysite, ethyl Examples thereof include acetoacetate aluminum diisopropoxide and the like, and mixtures thereof. Preferably, ethyl acetoacetate aluminum diisopropoxide is preferably used, which is obtained from Kawaken Fine Chemical Co., Ltd. under the trade name ALCH. Can be used.

  The amount of the gelling agent used is preferably from 0.1 to 5% by mass, more preferably from 0.5 to 3% by mass, as the content in the ink varnish.

  The ink of the present invention may be of an overprint varnish type that does not contain a colorant in the ink varnish, but may be of a type that contains a colorant. Examples of the colorant used in the present invention include inorganic pigments such as titanium oxide, barium sulfate, calcium carbonate, zinc white, and magnetic iron oxide, lake pigments, azo pigments, isoindoline pigments, phthalocyanine pigments, Examples thereof include organic pigments such as quinacridone pigments and anthraquinone pigments, carbon black and dyes, and one or more of these can be used. The content of the colorant in the ink is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, and most preferably 15 to 25% by mass.

<Ink production method>
As the method for producing the ink of the present invention, for example, the ink varnish and the colorant are premixed with a mixer, and then uniformly mixed with a three-roll mill, and the solvent and / or used for the preparation of the ink varnish are used. Alternatively, an ink tack is prepared by additionally blending the varnish. If necessary, additives such as paraffin wax, polyethylene wax, polytetrafluoroethylene wax, and other antifriction agents and plasticizers are uniformly kneaded and blended so long as they do not interfere with the object of the present invention. The ink varnish content in the ink of the present invention is preferably 50 to 90% by mass, more preferably 55 to 85% by mass, and most preferably 60 to 80% by mass.

  The offset printing ink composition of the present invention obtained as described above is an environmentally friendly ink that is excellent in printability and printing effect, and is suitably used for offset printing such as rotary offset and sheet-fed offset, and problems such as odor Gives good prints without.

[Examples 1 to 3, Comparative Example 1, Comparative Example 2, and Reference Example]
Using di-2-ethylhexyl sebacate, which is a diester of sebacate used in the present invention, a mixed solvent of dioctyl ether and 2-ethylhexyl caprylate used in a comparative example and dimethyl sebacate, and a petroleum solvent used as a reference example Examples of the varnishes a1 to a6 and the inks b1 to b6 using these varnishes will be described specifically with reference to examples, comparative examples, and reference examples. In the text, “parts” or “%” are based on mass unless otherwise specified. Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Hereinafter, the solvents used in Examples, Comparative Examples, and Reference Examples will be described.
・ Di-2-ethylhexyl sebacate (Ito Oil Co., Ltd., DOS)
・ Dimethyl sebacate (manufactured by Ito Refinery, DMS-C)
・ Dioctyl ether (reagent)
・ 2-ethylhexyl caprylate (reagent)
・ Petroleum solvents (reagents)

(Varnish preparation example a1)
A rosin-modified phenolic resin having a weight average molecular weight of 60,000 is used as the varnish resin, di-2-ethylhexyl sebacate is used as the solvent, and the amounts of the varnish resin, soybean oil, and solvent shown in Table 1 are added to the nitrogen stream. Stir at 200 ° C. for 30 minutes in the atmosphere, then cool to 150 ° C., then mix with a gelling agent (ALCH), and further heat and stir at 200 ° C. for 60 minutes to prepare varnish a1 did.

(Varnish preparation example a2)
A varnish a2 was prepared in the same manner as in the varnish preparation example a1 except that the amount of the solvent used in the varnish preparation example a1 was changed.

(Varnish preparation example a3)
A varnish a3 was prepared in the same manner as in the varnish preparation example a1 except that the amount of the solvent used in the varnish preparation example a1 was changed.

(Varnish preparation example a4)
Varnish a4 was prepared in the same manner as in varnish preparation example a1 except that the solvent used in Preparation Example a1 for the varnish was changed to a mixed solvent of dioctyl ether and palm-derived caprylic acid-2-ethylhexyl listed in Table 1. Was prepared.

(Varnish preparation example a5)
Varnish a5 was prepared in the same manner as in Varnish Preparation Example a1, except that the solvent used in Preparation Example a1 for the varnish was changed to dimethyl sebacate.

(Varnish preparation example a6)
Varnish a6 was prepared in the same manner as in Varnish Preparation Example a1, except that the solvent used in Preparation Example a1 for the varnish was changed to a petroleum solvent.

上記表１中の数値は部数を表わす。

The numerical values in Table 1 above represent the number of copies.

(Ink preparation)
65 parts each of the varnishes a1 to a6 prepared as described above and 18 parts of phthalocyanine blue were blended, and then the above-described ink tack was measured to be 10 to 11 in the incomometer measurement. The inks b1 to b6 were prepared by additionally blending the varnishes a1 to a6 and the respective solvents and kneading them uniformly. In addition, the above tack value is measured after applying 1.3 ml of the obtained ink on a roll of an incometer manufactured by Toyo Seiki Co., Ltd. and rotating at a roll temperature of 32 ° C. and a rotation speed of 1,200 rpm. Value.

  In addition, the content of di-2-ethylhexyl sebacate in the inks obtained in Examples 1 to 3 was 30% by mass for ink b1, 40% by mass for ink b2, and 50% by mass for ink b3. there were. Moreover, the content of soybean oil in the inks obtained in Examples 1 to 3 was 15% by mass for all of b1, b2, and b3.

<Evaluation example>
Each of the inks obtained in the above Examples, Comparative Examples, and Reference Examples was evaluated by the following measuring methods with respect to the evaporation drying property of the ink on the printing press, the on-press stability and the swelling property.

[Evaporation drying]
0.125 ml of each ink is developed on top coat paper using a RI tester 2-split roll manufactured by Ishikawajima Sangyo Co., Ltd. to produce a printed sample piece. Next, the printing material piece is heated using an oven capable of adjusting the temperature, and the ink surface is dried and solidified by operating the paper surface temperature. After heating, the print sample piece is allowed to cool for 1 minute, and the ink surface of the cooled print sample piece is rubbed with a white paper with a Gakushin type abrasion resistance tester, and the paper surface drying temperature when the color does not fade is measured. did. The evaluation results are shown in Table 2.

[Onboard stability]
Apply 0.5 ml of each of the above inks to an incometer manufactured by Toyo Seiki Co., Ltd., set the roll temperature to 32 ° C. and the rotation speed to 1,200 rpm, rotate the roll, and the initial tack value and its 1 minute The subsequent tack value was read, and the change over time in the tack value (difference ΔT from the initial value) was measured. The evaluation results are shown in Table 2.

[Swellability]
Apply a suitable amount of each of the above inks to the surface of a rubber blanket piece (manufactured by Di International Co., Ltd., Dibran 3000-4) and leave it at room temperature for 24 hours. It was evaluated by. The evaluation results are shown in Table 2.
○: No swelling or softening phenomenon is observed on the blanket surface.
Δ: Swelling or softening phenomenon is slightly observed on the blanket surface.
X: Swelling or softening phenomenon is recognized over the entire surface or part of the blanket surface.

[Odor evaluation]
The printed materials of the examples and comparative examples were randomly given to 10 members to be evaluated and evaluated for the presence or absence of off-flavors. The evaluation was made into a three-level evaluation with no off-flavor, a slight off-flavor, and off-flavor. The most common evaluation is shown in Table 2. Here, “No strange odor” is an evaluation when the odor was completely uncomfortable when smelling the printed material, and “Slightly unpleasant odor” is an evaluation when the odor was slightly uncomfortable when smelling the printed material. The evaluation is “with a bad odor”, which is an evaluation when the user feels an unpleasant odor when he or she smells the printed matter.

  As can be seen from Table 2, the inks of the present invention of Examples 1 to 3 are more suitable for printing and printing effects (drying properties) than the ink of Comparative Example 1 using a mixed solvent of a conventional fatty acid ester and an ether solvent. The stability on the machine was inferior, the rubber swelled little, and the printed matter had no odor.

  Further, unlike the 2-diethylhexyl sebacate used in Examples 1 to 3, the ink of Comparative Example 2 using dimethyl sebacate, which is a short-chain alkyl ester of sebacic acid, as a solvent has an appropriate drying property. It was confirmed that it was inferior to the on-machine stability, rubber swellability, and print odor.

Claims (5)

And 2 0 to 50 wt% of sebacic acid diester Le represented by the following general formula (1), and a crosslinking agent,
The crosslinking agent is a gelling agent;
The offset printing ink composition which does not contain solvents other than sebacic acid diester represented by the following general formula (1) and vegetable oil as a solvent component.
R ¹ OCO (CH ₂ ) ₈ COOR ² (1)
[In Formula (1), R ¹ and R ² are each a hydrocarbon group which may have a branch or an unsaturated bond, and the sum of the carbon atoms of R ¹ and R ² is from 4 18. ] The gelling agent is selected from aluminum ethyl acetate diisopropylate, aluminum isopropylate, aluminum stearate, ethyl acetoacetate aluminum diisopropylate, aluminum diisopropoxide, ethyl acetoacetate aluminum diisopropoxide, or mixtures thereof The offset printing ink composition according to claim 1. The offset printing ink composition according to claim 1 or 2, wherein the gelling agent is 0.1 to 5% by mass as a content in the ink varnish. The offset printing ink composition according to any one of claims 1 to 3, wherein R ¹ and R ² in the formula (1) are saturated hydrocarbon groups having 8 carbon atoms. The offset printing ink composition according to any one of claims 1 to 4, wherein the sebacic acid diester represented by the general formula (1) is di2-ethylhexyl sebacate.