JP2011137098A - Metal printing ink composition and printed metal plate using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal printing ink composition which has high gloss and high workability and excellent printability in the metal printing ink field, particularly in the printing ink for art cans, three-piece beverage cans, food cans and the like and a printed metal plate using the same. <P>SOLUTION: The metal printing ink composition includes a pigment, an alkyd resin, and a hydrocarbon solvent and part or the entire of the polyhydric alcohol component constituting the alkyd resin is tris(2-hydroxyethyl)isocyanurate, and the printed metal plate uses the metal printing ink composition. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a metal printing ink composition having high gloss, high workability, and excellent printability in printing inks used for art cans, three-piece beverage cans, food cans, etc., and a printed metal plate using the same. .

  Currently, there are two methods of metal printing: a method in which a metal is processed into a cylindrical shape and then printed by a letterpress offset method, and a method in which a sheet metal plate is printed by a planographic offset method and then processed into a cylindrical shape. Art cans, 3-piece beverage cans, food cans, etc. are mainly printed by the lithographic offset method. There are two types of curing methods for metal printing inks printed by the lithographic offset method: ultraviolet ray curing and oxidative polymerization curing by heating. In applications where high workability is required, it has been modified with drying oil and drying oil fatty acid. A method of heat-curing by oxidative polymerization of alkyd resin is frequently used.

  By the way, it is known that the processability in metal printing ink changes with content of the vegetable oil fatty acid utilized for alkyd resin (patent document 1). In general, an ink using an alkyd resin having a high content of vegetable oil fatty acid has poor processability, and an ink using an alkyd resin having a low content of vegetable oil fatty acid has good processability. For this reason, alkyd resins with high vegetable oil fatty acid content have high printability such as resin solubility, transferability, and on-machine stability because high processability inks use alkyd resins with low vegetable oil fatty acid content. This is inferior to the ink using resin.

  In addition, an alkyd resin having a large iodine value (unit: g of iodine bonded to 100 g of the sample) has a short distance between cross-linking points, resulting in a fine resin network structure and poor flexibility. On the other hand, an alkyd resin having a small iodine value has a long distance between cross-linking points, and the resin network is coarse and the flexibility is increased. Therefore, the workability of metal printing inks using these alkyd resins reflects the flexibility of the alkyd resins.

  For this reason, metal ink manufacturers prepare two types of inks: general types that emphasize printability for applications that do not require workability, and high-processability types for applications that require processability. ing. However, in recent years, as a part of rationalization from can manufacturers and metal printing manufacturers, there is a demand for metal ink manufacturers to develop metal printing inks for sheets that achieve both high workability and printability.

  The gloss in metal printing is affected by the smoothness of the surface of the coating film of the printing ink, that is, the leveling property. The gloss so far is not sufficient, but there is still room for improvement.

JP 2004-285303 A JP 2001-31889 A

  The present invention has been made in order to solve the above-mentioned problems, and the object thereof is to provide a metal printing ink composition having high gloss and high workability and excellent printability, and further the ink composition. It is to provide a printed metal plate printed by using.

  As a result of intensive studies, the present inventors have found that the above object can be achieved by adopting the following configuration, and have completed the present invention.

  That is, according to the present invention, in a metal printing ink composition containing a pigment, an alkyd resin, and a hydrocarbon solvent, the proportion of the vegetable oil fatty acid constituting the alkyd resin is 35 to 65% by mass, and 15 to 15 of the polyhydric alcohol component. The present invention relates to a metal printing ink composition in which 100 mol% is tris (2-hydroxyethyl) isocyanurate.

  In the present invention, the iodine value of the alkyd resin is preferably 55 to 130.

  The present invention also relates to a printed metal plate having an ink layer formed using the metal printing ink composition of the present invention on a metal plate or a metal base plate provided with a base coat layer on the metal plate.

  According to the ink composition of the present invention, the printability is excellent, and high gloss and high workability can be imparted to the printed metal plate. In particular, it is useful in printing inks for art cans, three-piece beverage cans, food cans and the like.

  Hereinafter, each component used for the metal printing ink composition of this invention is demonstrated in detail.

(Alkyd resin)
The alkyd resin used in the metal printing ink composition of the present invention has, as a skeleton, a condensate of a polybasic acid and a polyhydric alcohol having tris (2-hydroxyethyl) isocyanurate as a part or all of oil, fatty acid, or the like. The production method is not particularly limited, and known methods such as a transesterification method using oil as a raw material and a fatty acid method using fatty acid as a raw material can be used.

  In the present invention, tris (2-hydroxyethyl) isocyanurate used in the polyhydric alcohol component constituting the alkyd resin has a six-membered ring structure in which hydroxyl groups exist in three symmetrical directions. When the condensate of polybasic acid and tris (2-hydroxyethyl) isocyanurate is used as a skeleton, the distance between cross-linking points of the resin network structure is increased, thereby increasing the degree of freedom and expressing flexibility. Can be improved. Thus, by using tris (2-hydroxyethyl) isocyanurate, the improvement of processability was realized, so that the inclusion of vegetable oil fatty acid than the alkyd resin that has been used for ink having processability so far Large amounts of alkyd resins can be used, improving printability.

  Furthermore, the metal printing ink composition composed of an alkyd resin using tris (2-hydroxyethyl) isocyanurate has good fluidity at high temperature, and the coating surface at the time of heating and drying after coating becomes smooth. High gloss.

  In the present invention, 15 to 100 mol% of the polyhydric alcohol component constituting the alkyd resin is tris (2-hydroxyethyl) isocyanurate. If it is less than 15 mol%, it becomes difficult to balance printability and processability, and high gloss cannot be obtained.

  Polyhydric alcohol components other than tris (2-hydroxyethyl) isocyanurate include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexane. Diol, 1,9-nonanediol, 2-methyl-1,8-octanediol, neopentyl glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, tetramethylene glycol, 1,4-cyclohexanediol, 1 , 4-cyclohexanedimethanol, hydrogenated bisphenol A, dihydric alcohols such as 2-butyl-2-ethyl-1,3-propanediol; trihydric alcohols such as glycerin, trimethylolpropane, trimethylolethane Pentaerythritol, diglycerin, ditrimethylolpropane, can be used without tetravalent alcohols such as ditrimethylol ethane, polyhydric alcohols which have been used conventionally to alkyd resin is particularly limited. These may be used alone or in combination of two or more.

  The vegetable oil fatty acid component which is the other component of the alkyd resin used in the present invention includes linseed oil, tung oil, dehydrated castor oil, soybean oil, safflower oil, linseed oil fatty acid, tung oil fatty acid, dehydrated castor oil fatty acid, soybean oil fatty acid, sacrificial oil Examples include flower oil fatty acids, and unsaturated fatty acids such as oleic acid, linoleic acid, linolenic acid, eleostearic acid, or ricinoleic acid. These can be used alone or in combination of two or more. Linseed oil and linseed oil fatty acid are preferred in consideration of the price and physical properties of the coating film.

  In addition, some of these vegetable oils and fatty acids may be changed to monobasic acids other than fatty acids. As other monobasic acids, benzoic acid, pt-butylbenzoic acid, abietic acid, hydrogenated abietic acid, and the like can be used.

  Polybasic acids include aromatic dibasic acids such as (anhydrous) phthalic acid, isophthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid; tetrahydro (anhydrous) phthalic acid, hexahydro ( Alicyclic dibasic acids such as phthalic anhydride and 1,4-cyclohexanedicarboxylic acid; (anhydrous) succinic acid, alkenyl (anhydrous) succinic acid, fumaric acid, (anhydrous) maleic acid, itaconic acid, adipic acid, sebacine Examples thereof include aliphatic dibasic acids such as acid, azelaic acid and (anhydrous) hymic acid; (anhydrous) trimellitic acid, (anhydrous) pyromellitic acid, (anhydrous) methylcyclohexericarboxylic acid, and benzophenone tetracarboxylic acid. These polybasic acids may be used alone or in combination of two or more.

  The vegetable oil fatty acid content of the alkyd resin used in the metal printing ink composition of the present invention is 35 to 65% by mass. If the amount is less than 35% by mass, the fluidity of the ink is reduced when 15 to 100 mol% of tris (2-hydroxyethyl) isocyanurate is used as the polyhydric alcohol component. Hardness is inferior. More preferably, it is 45 to 60% by mass in consideration of the balance of ink fluidity, workability, and coating film hardness.

  Moreover, it is preferable that the iodine value of alkyd resin is 55-130. If it is less than 55, the coating film hardness is inferior, and if it exceeds 130, the workability tends to decrease. More preferably, it is 65 to 115 in consideration of the balance between the coating film hardness and the workability.

  Furthermore, conventionally used resins can be mixed with the alkyd resin of the present invention. That is, a known resin that is compatible with the alkyd resin can be used alone or in combination, depending on the required performance such as printability and coating film properties. Specifically, for example, rosin-modified phenol resin, polyester resin, petroleum resin, epoxy resin, ketone resin, rosin-modified maleic acid resin, amino resin, benzoguanamine resin and the like can be exemplified.

  If necessary, a printing ink dryer may be added to the oxidation polymerization curable printing ink as a curing accelerator for curing the ink. In the present invention, a printing ink dryer may also be added. Examples of printing ink dryers that can be used in the present invention include metals such as cobalt, manganese, lead, iron, and zinc, octylic acid, naphthenic acid, neodecanoic acid, tung oil fatty acid, linseed oil fatty acid, soybean oil fatty acid, resin acid, etc. Examples thereof include salts with carboxylic acids, that is, metal soaps. These can be used alone or in combination of two or more.

(Pigment)
As the pigment used in the present invention, known inorganic or organic pigments for printing inks can be used singly or in combination. Specific examples include pigments described in Patent Document 2 and the like.

(Hydrocarbon solvent)
The hydrocarbon solvent as a solvent for metal printing ink used in the ink composition of the present invention can be a hydrocarbon solvent having a boiling point range of about 200 to 400 ° C., usually used for metal printing ink, There is no particular limitation.

  As the hydrocarbon solvent, a normal petroleum solvent or an alkylbenzene solvent is preferably used. Examples of the petroleum solvent include AF5, 6, 7 solvent manufactured by Nippon Oil Corporation. Examples of the alkylbenzene-based solvent include Alkene 56N, L, 200P manufactured by Shin Nippon Petrochemical Co., Ltd., BAB manufactured by UIC, and the like, which can be used alone or in combination.

  The amount of the hydrocarbon-based solvent used is not particularly limited as long as the tack value of the ink that is normally printed can be adjusted in the range of 5 to 40.

(Other ingredients)
A known pigment dispersant, wax, stabilizer, acid catalyst, and the like can be added to the ink composition of the present invention as other components, if necessary.

  In addition, fine powder silica, organic bentonite and the like may be added to the ink as an auxiliary agent within the range not impairing the object of the present invention, and the use of a gel varnish with a metal chelate or a sorbitol compound as a varnish component for printing ink Is also possible.

  The metal printing ink composition of the present invention can be prepared by a conventional method using a roll mill, a ball mill, a bead mill or the like.

  The metal plate on which the ink composition of the present invention is printed includes a metal plate such as stainless steel, aluminum, tin-plated steel plate, tin-free steel, or a metal plate provided with a base coat (primer) layer on these metal plates. Although a ground plane is suitable, it is not limited to these. For forming the base coat layer, for example, a base coat composition such as a size paint or white coating generally used in metal printing can be used. The pet film may be laminated.

  As a method for printing the metal printing ink composition of the present invention on these metal plates, printing can be easily performed by a normal printing method such as an offset method using dampening water or a dry offset method. The ink film thickness is arbitrary, but may be within a range of 0.1 to 6 μm, for example.

  For curing the metal printing ink composition of the present invention, an oven used for ordinary metal printing can be used, and the heating temperature is usually in the range of 120 to 230 ° C. The heating time is arbitrary as long as it is 3 minutes or longer, but is usually performed in the range of 3 to 30 minutes.

  The printed metal plate of the present invention thus obtained does not necessarily require the application of an overprint varnish, but better coating film properties can be obtained by using the overprint varnish.

  When coating the overprint varnish on the metal printing ink printing layer of the printing metal plate of the present invention, it is usually preferable to carry out after heat curing the metal printing ink composition of the present invention, but a wet-on-wet system It is also possible to heat and cure both at the same time after coating with.

  Since the metal printing ink composition of the present invention has excellent printability and can form a highly glossy and highly workable ink coating on a metal plate, it is suitably used as a sheet metal printing ink. be able to.

  Hereinafter, the present invention will be described based on synthesis examples, examples and the like, but the present invention is not limited to these examples. In addition, the part and% in each example are based on a mass reference | standard.

Synthesis example 1
A reactor equipped with a stirrer, water separator, condenser, nitrogen inlet tube and thermometer was charged with 45 parts of linseed oil fatty acid, 25.4 parts of phthalic anhydride, 26.3 parts of THEIC, and 9.3 parts of glycerin, and nitrogen. The reaction was performed at 220 to 230 ° C. until the acid value was 10 or less while circulating xylol in the presence of gas, and then xylol was separated by distillation to obtain a liquid alkyd resin (1). The amount of dehydration was 6.0 parts. Moreover, the iodine value of this resin (1) was 86 (Iodine value was measured in accordance with JISK0070. The same applies hereinafter).

Synthesis example 2
In the same reactor as in Synthesis Example 1, 50 parts of linseed oil fatty acid, 20.9 parts of phthalic anhydride, 23.0 parts of THEIC, and 11.8 parts of trimethylolpropane were charged, and xylol was circulated in the presence of nitrogen gas. After reacting at 220 to 230 ° C. until the acid value became 10 or less, xylol was separated by distillation to obtain a liquid alkyd resin (2). The dehydrated amount was 5.7 parts. Moreover, the iodine value of this resin (2) was 93.

Synthesis example 3
In the same reactor as in Synthesis Example 1, 50 parts of linseed oil fatty acid, 21.1 parts of isophthalic acid, 32.4 parts of THEIC, 4.2 parts of pentaerythritol were charged, and xylol was circulated in the presence of nitrogen gas. After reacting at 230 ° C. until the acid value became 10 or less, xylol was separated by distillation to obtain a liquid alkyd resin (3). The amount of dehydration was 7.7 parts. Moreover, the iodine value of this resin (3) was 95.

Synthesis example 4
In the same reactor as in Synthesis Example 1, 40 parts of dehydrated castor oil fatty acid, 25.6 parts of phthalic anhydride, 26.5 parts of THEIC, and 13.6 parts of trimethylolpropane were charged, and xylol was circulated in the presence of nitrogen gas. After reacting at 220 to 230 ° C. until the acid value became 10 or less, xylol was separated by distillation to obtain a liquid alkyd resin (4). The dehydrated amount was 5.7 parts. Moreover, the iodine value of this resin (4) was 60.

Synthesis example 5
In the same reaction apparatus as in Synthesis Example 1, 45 parts of linseed oil fatty acid, 30.7 parts of isophthalic acid, 11.1 parts of THEIC, and 22.7 parts of trimethylolpropane were charged, and xylol was circulated in the presence of nitrogen gas, After reacting at ˜230 ° C. until the acid value became 10 or less, xylol was separated by distillation to obtain a liquid alkyd resin (5). The dehydration amount was 9.5 parts. Further, this resin (5) had an iodine value of 87.

Synthesis Example 6
In the same reactor as in Synthesis Example 1, 55 parts of linseed oil fatty acid, 14.6 parts of isophthalic acid and 37.1 parts of THEIC were charged, and the acid value was 10 at 220 to 230 ° C. while circulating xylol in the presence of nitrogen gas. After making it react until it becomes below, xylol was separated by distillation and liquid alkyd resin (6) was obtained. The amount of dehydration was 6.7 parts. The iodine value of this resin (6) was 106.

Synthesis example 7
In the same reactor as in Synthesis Example 1, 30 parts of linseed oil fatty acid, 30.0 parts of phthalic anhydride, 30.1 parts of THEIC, and 15.4 parts of trimethylolpropane were charged, and xylol was circulated in the presence of nitrogen gas. After reacting at 220 to 230 ° C. until the acid value became 10 or less, xylol was separated by distillation to obtain a liquid alkyd resin (7). The amount of dehydration was 5.5 parts. Moreover, the iodine value of this resin (7) was 56.

Synthesis Example 8
In the same reactor as in Synthesis Example 1, 70 parts of dehydrated castor oil fatty acid, 6.5 parts of phthalic anhydride, 23.6 parts of THEIC, and 5.2 parts of trimethylolpropane were charged, and xylol was circulated in the presence of nitrogen gas. After reacting at 220 to 230 ° C. until the acid value became 10 or less, xylol was separated by distillation to obtain a liquid alkyd resin (8). The amount of dehydration was 5.3 parts. Further, this resin (8) had an iodine value of 110.

Synthesis Example 9
In the same reactor as in Synthesis Example 1, 40 parts of linseed oil fatty acid, 31.9 parts of phthalic anhydride and 34.5 parts of trimethylolpropane were charged at 220 to 230 ° C. while circulating xylol in the presence of nitrogen gas. After reacting until the acid value became 10 or less, xylol was separated by distillation to obtain a liquid alkyd resin (9). The dehydration amount was 6.4 parts. Moreover, the iodine value of this resin (9) was 75.

Synthesis Example 10
In the same reactor as in Synthesis Example 1, 60 parts of linseed oil fatty acid, 21.8 parts of isophthalic acid, 4.8 parts of THEIC, and 22.0 parts of trimethylolpropane were added, and while xylol was circulated in the presence of nitrogen gas, 220 After reacting at ˜230 ° C. until the acid value became 10 or less, xylol was separated by distillation to obtain a liquid alkyd resin (10). The amount of dehydration was 8.6 parts. Further, this resin (10) had an iodine value of 115.

  Table 1 shows the compositions and properties of the alkyd resins obtained in Synthesis Examples 1 to 10, respectively.

Example 1
15 parts of Lionol Blue FG-7351 (manufactured by Toyo Ink Co., Ltd.) as a pigment, 60 parts of alkyd resin (1), 1 part of manganese naphthenate, 25 parts of alkylbenzene (manufactured by UIC, BAB) as a hydrocarbon solvent, The mixture was kneaded using a three-roll mill to obtain indigo ink (1).

  The obtained indigo color ink (1) was used to print on a metal plate, and the curability, gloss, workability and printability were evaluated by the following methods. The results are shown in Table 2.

<Curing test>
A printing plate on which 0.3 mL of ink is printed on an electric tin-plated steel plate (tinplate) with a RI tester (manufactured by Mei Seisakusho) 2-split roll is heated in an electric oven at 150 ° C. for 10 minutes. After heat drying, the plate temperature is cooled to room temperature, and the pencil hardness of the printed surface is measured based on JIS K5400.
Evaluation criteria ○: The ink surface of the printing plate is not scratched with an HB pencil.
Δ: The ink surface of the printing plate is scratched by HB but not scratched by B.
×: B scratches on the ink surface of the printing plate.

<Gloss evaluation>
The image quality of the ink surface of the printing plate heat-cured in the curing test, that is, the clarity of the fluorescent lamp image projected onto the ink surface is visually observed.
Evaluation criteria ○: The image of a fluorescent lamp is clear.
Δ: Medium fluorescent image.
X: The fluorescent lamp image is unclear.

<Workability test>
On the printing plate prepared by the above-described curability test, a clear coating for metal sheet manufactured by Toyo Ink Manufacturing Co., Ltd. was applied so that the coating amount was 60 mg / 100 cm ² and was cured by heating in an electric oven at 160 ° C. for 10 minutes. To do. The printed coated plate is processed into a square can (depth is 20 mm and the diameter of each corner is 4, 6, 8, 10 mm) with a press machine at room temperature, and each corner is visually observed.
Evaluation criteria ○: No peeling of the coating film is observed.
X: The film can be peeled off.

<Printability test>
Using a high-speed printing aptitude tester (SMTT Co., Ltd. PM904PT), collect the ink on a test rubber roll so that the ink film thickness is 1 μm, and move the electrotinned steel sheet at a speed of 2 m / s while moving the ink. Print on a tin-plated steel sheet from a rubber roll, and after heat-curing, observe the ink transfer state. The ink film was evaluated as ◯ for a crushed and smooth finish: △, medium for △, and poor for crushed and visible undercoat: x.

Examples 2-6 and Comparative Examples 1-4
Inks (2) to (10) were prepared in the same manner as in Example 1 except that the resins (2) to (10) respectively synthesized in Synthesis Examples 2 to 10 were used as alkyd resins and the blending ratios shown in Table 2 were used. Each characteristic was evaluated. The results are shown in Table 2.

  From Table 2, a metal printing ink using tris (2-hydroxyethyl) isocyanurate for a part or all of the polyhydric alcohol component and using an alkyd resin having a vegetable oil fatty acid content in a specific range, It can be seen that it was possible to achieve both printability and processability, which could not be achieved before, and furthermore, high glossiness could be expressed.

Claims (3)

In the metal printing ink composition containing a pigment, an alkyd resin and a hydrocarbon solvent, the proportion of the vegetable oil fatty acid constituting the alkyd resin is 35 to 65% by mass, and 15 to 100 mol% of the polyhydric alcohol component is tris. A metal printing ink composition which is (2-hydroxyethyl) isocyanurate. 2. The metal printing ink composition according to claim 1, wherein the iodine value of the alkyd resin is 55 to 130. The printed metal plate which has an ink layer formed using the metal printing ink composition of Claim 1 or 2 on the metal base plate which provided the base coat layer on the metal plate or the metal plate.