JP6226772B2 - Ink composition for jet printer - Google Patents

Description

  The present invention provides scratch resistance, abrasion resistance, adhesion to packaging materials such as packaging containers in the field of food packaging, especially polyolefin resin molded containers and caps, or paper containers coated with polyolefin resin coatings. It is related with the ink composition for jet printers excellent in.

  Food packaging containers are required by law to display information such as the date of manufacture, expiration date, or expiration date, and inkjet printers that can be implemented at high speed are generally used as means for printing such information. Has been adopted.

In printing on packaging containers using inkjet printers, there are restrictions on the heating and drying means that can be used, especially in polyolefin packaging containers, in order to avoid adverse effects on the quality of the contents of the packaging containers, resulting in insufficient adhesion In the manufacturing process and distribution process of products, there are frequently problems that the prints are rubbed and faded, or scraped off and lost.
Therefore, various improvement proposals have been made for the purpose of improving resistance to rubbing and scratching in the manufacturing process or distribution process of products.

JP 2000-38530 A Japanese Patent Laid-Open No. 10-195356 Japanese Patent Laid-Open No. 11-181345 JP-T-2001-520298 JP 2002-201393 A JP 2002-146245 A JP 60-077654 JP 2005-330298 A JP 2011-105818 A JP 2010-275467 A

  Patent Document 1 discloses an inkjet ink having sufficient adhesion and durability to a packaging film such as polypropylene without corona discharge treatment, and Patent Document 2 includes a chlorinated polyolefin resin and an imino group-containing dye. An ink for jet printing with improved adhesion is described. Patent Document 3 discloses an ink-jet ink having improved blocking properties composed of a chlorinated polyolefin resin, a liquid epoxy resin, and a silicone-acrylic resin. Patent Document 4 discloses an anti-abrasion-resistant ink containing cellulose nitrate and a rosin resin. A good jet ink is described, and Patent Document 5 describes an inkjet ink containing a butyral resin and methyl acetate as a solvent.

Although all of these disclosed examples are described as ink-jet inks having good adhesion to a substrate such as polyethylene or polypropylene, in fact, regarding the abrasion resistance in the above disclosed examples, Patent Document 1 Then, 50 times friction by felt at a load of 0.5 kg / cm ² , Patent Documents 2 and 3 are not described, Patent Document 4 has 10 times friction by thumb belly, and Patent Document 5 has no description of specific evaluation.
As described above, since the inks described in Patent Documents 1 to 5 are still insufficient in abrasion and abrasion resistance, various attempts have been made to improve abrasion resistance as ink-jet inks. Patent Documents 6 to 10 can be mentioned.

  Patent Document 6 describes an ink-jet printer ink using carbon black having a specific specific surface area as a pigment, Patent Document 7 describes an ink-jet ink using an acrylic resin, and Patent Document 8 An oil-based pigment ink using a polyester resin, an acrylic resin, a polyurethane resin, or a vinyl chloride resin is described. Patent Document 9 includes an ink flow adjusting resin and a leveling agent in addition to a binder resin such as a polyester resin or a vinyl chloride copolymer resin. The ink jet ink used in combination is described.

In Patent Document 6, the thumb belly is 50 times, in Patent Document 7, the finger friction, in Patent Document 8, the eraser is frictioned 5 times, in the Patent Document 9, the commercially available eraser is frictioned 30 times, and the 2 kg load cardboard is 300 times. It is disclosed that the wear resistance is evaluated by friction and the wear resistance is improved.
However, none of these disclosed examples have any adhesion to the polyolefin resin substrate, and further improvement in the adhesion of the ink to a difficult-to-adhere substrate such as the polyolefin resin substrate. It has been demanded.

  Recently, due to various problems related to food hygiene, with respect to date printing such as the expiration date, packaging containers made of polyolefin resin base materials, which are difficult to adhere to, have been required to be more resistant to abrasion and abrasion. The inks described in the above Patent Documents 1 to 9 are still insufficient in abrasion and abrasion resistance, or they have abrasion and abrasion resistance but have insufficient adhesion to a polyolefin resin substrate, resulting in a superior jet. At present, the development of ink for printers is desired.

In addition, the conventional inks described in Patent Documents 1 to 5 described above that have adhesion and abrasion resistance to the polyolefin resin base material satisfy the abrasion resistance evaluation criteria described in the respective documents. Even if it is a product, there are complaints such as the fact that the printed product is faint when it is transported, and the fact is that there is a demand for more scratch and abrasion resistant ink. is there.
As described above, in printing such as the expiration date, it is particularly important to take measures against disappearance or fading due to wear or abrasion.

  In the above-mentioned patent document 10, the present inventors have good adhesion to a polyolefin resin substrate by combining a vinyl chloride-vinyl acetate copolymer resin and a chlorinated polyolefin resin, and are commercially available erasers. An ink-jet ink that is abrasion resistant and does not faint even after being rubbed strongly 20 times has been disclosed.

As the vinyl chloride copolymer resin in Patent Document 10, a resin produced by a solution polymerization method gives good results. However, the production of vinyl chloride resin of solution polymerization method has been discontinued at home and abroad, and the technology of the invention cannot be supplied.
Accordingly, an object of the present invention is to provide an ink for a jet printer having good adhesion, scratch resistance, and abrasion resistance in the field of packaging containers using a polyolefin resin base material. .

According to the present invention, in the ink composition for a jet printer including a binder resin, a leveling agent, a coloring matter, and a solvent, the binder resin includes a thermoplastic polyester resin having a number average molecular weight of 8,000 to 25,000 and a weight average molecular weight of 10. Abrasion resistance and scratch resistance characterized by combining a chlorinated polyolefin resin having a chlorine content of 10 to 50% by weight in a weight blending ratio of 7/3 to 3/7 And the ink composition for jet printers for packaging materials excellent in adhesiveness is provided.
According to the present invention, there is also provided a polyolefin resin packaging material on which the ink composition for a jet printer for packaging material is printed, wherein the polyolefin resin packaging material is a molded container or paper whose outermost layer is made of polyethylene or polypropylene. There is provided a polyolefin resin packaging material, which is a container, a pouch container, a cap, or a sheet product for heat sealing.

  The ink composition for a jet printer according to the present invention combines a specific thermoplastic polyester resin and a chlorinated polyolefin resin as a binder resin, so that it is much more resistant than a vinyl chloride resin by a suspension polymerization method or an emulsion polymerization method. Excellent scratch resistance, abrasion resistance, adhesion, and performance equivalent to or better than vinyl acetate resin by solution polymerization. Specifically, the friction test with a 2 kg load corrugated cardboard makes it possible to print more than 300 times of abrasion resistance, and moreover, press the eraser strongly and print with wear resistance of more than 30 times. Also, it has good adhesion to difficult-to-adhere substrates such as polyolefin resin substrates.

The present invention will be described in more detail.
[Binder resin]
(Thermoplastic polyester resin)
In the jet printer ink of the present invention, the number average molecular weight of the thermoplastic polyester resin used as the binder resin is preferably 8,000 to 25,000, and more preferably 10,000 to 20,000.
If the number average molecular weight is lower than 8,000, the coating tends to be brittle and the abrasion resistance and scratch resistance tend to be weak. If it is larger than 25,000, the viscosity with respect to the desired binder resin amount in the ink increases. There is a tendency for ink suitability for jet printers to decrease.
Further, the glass transition temperature of the thermoplastic polyester resin is preferably 20 ° C. or higher. It is particularly preferably 30 ° C. or higher. When the glass transition temperature is lower than 20 ° C., the ink film becomes soft, the scratch resistance becomes weak, and there is a risk that harmful effects such as blocking may occur particularly in summer.

  Thermoplastic polyester resin is soluble in general-purpose organic solvents such as methyl ethyl ketone, glycol ether, and toluene, and has excellent adhesion to substrates such as metal, glass, polyester film, PVC resin film, nylon, and cellophane. In the present invention, although it has superior performance compared to other resins, its adhesion to a polyolefin resin substrate such as polyethylene or polypropylene is weak.

  Representative examples of the thermoplastic polyester resin used in the present invention include Byron of Toyobo Co., Ltd. and Eritel of Unitika Co., Ltd. Other than that, Hi-Milac, DIC Co., Ltd. of Dainichi Seika Kogyo Co., Ltd. ) Crisbon, Nippon Polyurethane Industry Co., Ltd. Nipponran, Nippon Synthetic Chemical Co., Ltd. Polyester.

(Chlorinated polyolefin resin)
Examples of the chlorinated polyolefin resin used in the present invention include chlorinated polyethylene, chlorinated polypropylene, acrylic-modified or urethane-modified chlorinated polyolefin resin, and the like.
The chlorine content in the resin is 10 to 60% by weight and the weight average molecular weight is in the range of 10,000 to 100,000, more preferably 20,000 to 800,000.
Although the above chlorinated polyolefin resin alone is inferior in abrasion resistance and abrasion resistance to the above-mentioned thermoplastic polyester resin, it has good adhesion to a polyolefin resin substrate.

  Stabilizers for chlorinated polyolefins include allyl glycidyl ether, phenyl glycidyl ether, diglycidyl ether of bisphenol A, epoxidized vegetable oils, epoxidized fatty acids, aliphatic and aromatic amines, metal soaps such as calcium stearate, organic acids In addition, chlorinated polyolefin resins containing a stabilizer are commercially available from, for example, Nippon Paper Chemicals Co., Ltd., and may be used as they are.

The blending ratio of the thermoplastic polyester resin and the chlorinated polyolefin resin is preferably 7/3 to 3/7 by weight.
When the amount of the thermoplastic polyester resin is less than 30% by weight, the abrasion resistance and the abrasion resistance are weakened. On the other hand, when the chlorinated polyolefin resin is less than 30% by weight, the adhesion to the polyolefin resin substrate becomes weak.
The blending ratio of the thermoplastic polyester resin and the chlorinated polyolefin resin is more preferably 6/4 to 4/6, and it is possible to achieve a good balance between adhesion, abrasion and abrasion resistance.

The total content of the thermoplastic polyester resin and chlorinated polyolefin resin in the ink is determined by the characteristics of the thermoplastic polyester resin used, but if it is less than 7% by weight, the printed film becomes thin and wear and scratch resistance are reduced. Further, it is disadvantageous, and the dye retention is also lowered. When the content exceeds 20% by weight, the ink viscosity becomes too high, and the ink suitability for the jet printer is lowered.
Therefore, the total content of the thermoplastic polyester resin and the chlorinated polyolefin resin in the ink is preferably 8 to 15% by weight.

(Other blendable resins)
The resins that can be blended include acrylic resins, epoxy resins, polyamide resins, rosins and their esters, phenol-modified rosins, maleic acid-modified rosins, terpenes and phenol-modified terpene resins, styrene-maleic resins, xylene resins, coumarone-indene resins. , Ketone resins, various celluloses, butyral resins, phenol resins, novolac resins, silicon-acrylic resins, and the like.
The blending amount of these resins can be used as long as the properties of the thermoplastic polyester resin and chlorinated polyolefin resin in the present invention are not impaired, but at most does not exceed 20% by weight of the total resin amount. Beyond this, adhesion to the polyolefin resin substrate, rubbing, and wear resistance will be reduced.

[Dye]
Examples of the dye that can be used in the present invention include oil-soluble dyes such as monoazo, disazo, metal complex, cyanine, and triphenylmethane, but are not limited to these, and particularly metal complex salts. Dyes are preferred. For example,
Solvent black 22, 23, 27, 29, 34, 43, 123
Solvent Yellow 19, 21, 32, 61, 79, 80, 81, 82
Solvent Red 8, 35, 83, 84, 100, 109, 118, 119, 121, 122, 160
Solvent Blue 25, 55, 70
Etc.
These metal-containing complex salt dyes are Bali Fast Color from Orient Chemical Industry Co., Ltd., Eisenspiron from Hodogaya Chemical Industry Co., Ltd., other BASF Co., Ltd., Nippon Ciba Geigy Co., Ltd., Nippon Kayaku Co., Ltd., Chuo Gosei Co., Ltd. It is sold by Chemical Co., Ltd.

These are more advantageous than other pigments in terms of adhesion to the polyolefin resin substrate, and can provide appropriate conductivity to the ink. Therefore, a conductive agent that is a negative factor is used for adhesion. There is an advantage that can be avoided.
In addition, the following dyes may be used as long as the properties of the metal complex dye are not impaired.
Examples thereof include oil-soluble dyes such as Solvent Black 3, Solvent Blue 7, 11 and Solvent Red 3, 19, 23, 24. Typically, there are oil colors from Orient Chemical Industry Co., Ltd. Further Basic Violet 1, 3, 4, 14
Basic blue 5, 7
Basic dyes such as Basic Red 1, 2, 8, 9
Acid dyes such as Acid Black 1, 2, and 31 may be mentioned, but the dye is not limited to these, and two or more of these may be used in combination.

It is important that the amount of the dye is 2 to 10% by weight based on the total ink weight. If the amount is less than this, the color tone of the printing becomes thin and the appearance is poor. In addition, ink jet aptitude is also deteriorated.
On the other hand, if the ratio of the amount of the dye to the total ink weight is larger than this, the retention of the dye will be lowered depending on the amount of the binder resin, and the resistance to abrasion, scratching, and hand scratching will be significantly lowered. In addition, ink jet aptitude is also deteriorated.

[Leveling agent]
In order to adjust the wettability and dot shape of the ink film, a silicone-based or fluorine-based surfactant is used.
Alkyl-modified silicones such as methyl, dimethyl and phenyl, phenylalkyl groups and fatty acid-modified silicones, alkoxy-modified silicones such as polyoxyethylene and polyoxypropylene, polyalkyl ether-modified silicones and polyalkyl ether siloxane compounds can be used.
Typical silicone leveling agents include FZ2123, 2208, KF-56 manufactured by Toray Dow Corning Co., Ltd., or Silface SAG manufactured by Nissin Chemical Co., Ltd.

Specific examples of the fluorine-based leveling agent include DSM-403M manufactured by Daikin Industries, Ltd. and Megafac F-556 manufactured by DIC Corporation.
These may be used alone or in combination. The amount of the leveling agent added is preferably from 0.1 to 2% by weight, more preferably from 0.2 to 1% by weight in the ink.

[solvent]
The solvent that can be used in the present invention may be any solvent such as ketone, alcohol, glycol ether, aromatic such as toluene, ester, etc., but these solvents should have a boiling point of 110 ° C. or less. It is important for maintaining quick drying, and the amount of these solvents is preferably 80% by weight or more of the total solvent.
The ink viscosity is preferably 0.8 cp / 20 ° C. or less. If the viscosity of the solvent is higher than this, the viscosity of the ink increases, and the amount of the binder resin is limited.

Typically, acetone, methyl ethyl ketone, methyl isopropyl ketone, methyl propyl ketone, diethyl ketone, methanol, ethanol, n-propanol, isopropanol, isobutanol, ethyl acetate, isopropyl acetate, toluene, methyl cellosolve, 1,2-dimethoxyethane Etc.
From the viewpoint of the solubility of the thermoplastic polyester resin and the chlorinated polyolefin resin, particularly preferred solvents are ketone solvents such as methyl ethyl ketone, methyl isopropyl ketone, methyl propyl ketone, and diethyl ketone, 1,2-dimethoxyethane, and the like.
These can be used alone or in combination. Further, from the viewpoint of supplementing polarity, a lower alcohol such as methanol can be partially used.

For the main solvent suitable for the thermoplastic polyester resin or chlorinated polyolefin resin, a solvent having a higher boiling point and higher viscosity than the main solvent may be used.
These solvents suppress the printing dots from becoming donut-shaped and have a compact and flat shape, and thus have an effect of improving wear resistance compared to the case of a donut shape.
The boiling point is preferably 10 ° C. or more higher than the main solvent, but in order not to impair the drying property, it is 150 ° C. or less, and the amount used is preferably 20% by weight or less of the total solvent amount.
The viscosity of the solvent is preferably 1.0 cp / 20 ° C. or higher.

[Conductive agent]
In a continuous ink jet, it is necessary to make the ink conductive.
In the present invention, when a metal-containing complex dye is used, it is not necessary to use a conductive agent because it has its own conductivity. However, if it is necessary to supplement conductivity, the following conductive agent is used. be able to.
Various inorganic salts such as lithium nitrate, lithium chloride, potassium bromide, sodium iodide, potassium thiocyanate, ammonium thiocyanate, alkyl and aryl quaternary ammonium salts and phosphonium salts, alkyl and arylamine and alkanolamine hydrochlorides, etc. There are organic salts. Of course, it is not restricted to the electrically conductive agent described here, The electrically conductive agent generally used in this field | area can be used.
These may be used alone or in admixture of two or more.
The addition amount of the conductive agent should be limited to the range of 0.1 to 1% of the ink weight, and if it is large, the physical properties of the printed film may be impaired.

[Other additives]
In the present invention, in addition to the binder resin, leveling agent, dye, solvent, and conductive agent, a lubricant, a surfactant, a plasticizer, an alkoxysilane, and the like as long as the properties of the ink composition of the present invention are not impaired. Additives may be used.
Hydrocarbons, fatty acids, fatty acid amides, esters, alcohols, metal soaps, etc. are commonly used as lubricants. Fatty acid amide lubricants are particularly effective in improving abrasion resistance and wear resistance. There is.

Either a fatty acid amide or an alkylene bis fatty acid amide can be used.
Since fatty acid amides have a long-chain alkyl group and a strong polar amide group in the molecule, they have good compatibility with the binder resin, and exhibit a unique behavior of bleeding on the surface of the substance and a high lubricant effect.
For example, one or more fatty acid amide-based lubricants selected from oleic acid amide, erucic acid amide, ethylene bis-oleic acid amide, lauric acid amide, stearic acid amide, and esylic acid amide can be used.
The ink composition for a jet printer according to the present invention is advantageous when high-speed printing is performed in the field of packaging containers or the like by a continuous method IJP, but the application method is not limited to this, and an on-demand or piezo method is used. It can be applied to various printers.

The ink composition for a jet printer of the present invention may be heated after printing, and as a heating method, a method of spraying heated air on a printed information portion of a product moving on a conveyor, a jig such as a heating roll is used. A method of pressing the printed information part or a method of heating the printed packaging container itself in a heating oven can be used, but it is necessary to heat it under conditions that do not impair the quality of the form of the container and the performance of the container. is there.
The heating method is not limited to the methods listed here.

The object that can be printed using the ink composition for a jet printer of the present invention can be particularly suitably used for a bottle molded with a polyolefin resin substrate, a cup container, or a packaging container coated with a polyolefin resin substrate. .
Needless to say, the present invention is not limited to the packaging container, and can be used for metal containers, flexible packages whose surface layer is made of nylon or polyester, synthetic resin bottles, caps, glass containers, and the like. Moreover, it can be widely used not only in the field of packaging containers but also in other fields such as other containers, appliances, electric parts, etc. where printing or marking is generally performed by IJP.
EXAMPLES Hereinafter, although an Example demonstrates this invention, in any case, the scope of the present invention is not restrict | limited by these Examples.

[Evaluation method]
(1) Ink suitability for jet printer Using a continuous type CX-RH model manufactured by Hitachi Industrial Equipment Co., Ltd., the printable area was examined by changing the frequency and the excitation voltage. In addition, the operation of about 8 hours a day was conducted for 1 month, and the inkjet suitability was examined. ○: The printable excitation voltage range was 10 or more. The possible frequency band was wide and the inkjet suitability was good. △: The above frequency band was slightly narrow. Ink-jet suitability is good ×: Printability is narrow, ink-jet suitability is poor XX: Ink storage stability is poor, and ink-jet operation is impossible

Using an ink jet printer, print marking was applied to untreated polypropylene and polyethylene films that were not subjected to surface treatment such as corona discharge, and were subjected to the following evaluation.
(2) Corrugated cardboard abrasion test A corrugated cardboard for packaging containers is cut into a 10 cm square, and attached to a 2 kg weight with the inner surface facing outward. The cardboard surface is placed on the printing surface and rubbed at a speed of about 60 times / minute with a stroke of about 6 to 7 cm. The cardboard was replaced for each sample.
◎: No blurring of prints even after rubbing 300 times or more ○: Slightly fading is seen after rubbing 300 times, but interpretation is good △: Fading is seen at about 200th time, but interpretation is possible ×: Quite under 100 times Blurred and difficult to read

(3) Abrasion test A commercially available dragonfly eraser is pressed firmly against the print surface and rubbed.
◎: No fading even when rubbed 30 times or more ○: Slightly thin but readable when rubbed 20 times △: Pretty thin after 15 times but still readable ×: Printing disappears after 10 times

Adhesion test (4) Cellophane peeling test A commercially available Nichiban adhesive cellophane tape was attached to the printing surface to conduct a peeling test.
◎: No peeling is observed ○: Print is thin but can be read easily △: Partially peeled and the entire print is thin but can be read ×: It is peeled off and difficult to read or completely peeled

(5) Hand scrubbing Using a sample printed on a polyethylene film, hand scrubbing was performed 10 times so as to grab both chopsticks of the printed film by hand and rub the printed part.
○: Peeling is not seen △: Some prints are faint but can be read ×: Peeled considerably and difficult to read

(6) Appearance Printed on a polypropylene film, visually observed the color of the print, and rubbed several times with water wet fingers to observe the printing blur.
○: No change △: Light color or slight color blurring ×: Color is very light or pigment blurring is quite visible and the periphery of the print is dirty

[Materials used]
The materials used in the following examples are shown together with the symbols used in Table 1.
(1) Binder resin thermoplastic polyester resin A1: Byron 240 (Toyobo Co., Ltd.), number average molecular weight 15,000, Tg 60 ° C.,
A2: Byron 270 (Toyobo Co., Ltd.), number average molecular weight 23,000, Tg 67 ° C.
A3: Byron GK640 (Toyobo Co., Ltd.), number average molecular weight 18,000, Tg 79 ° C., A4: Byron UR8200 (Toyobo Co., Ltd.), number average molecular weight 25,000, Tg 73 ° C.
A5: Polyester TP235 (Nippon Synthetic Chemical Co., Ltd.), number average molecular weight 16,000, Tg 65 ° C.
A6: Elitel UE3200 (Unitika Ltd.), number average molecular weight 16,000, Tg 65 ° C.
A7: Byron GK250 (Toyobo Co., Ltd., number average molecular weight 10,000, Tg 60 ° C.,
A8: Byron 226 (Toyobo Co., Ltd., number average molecular weight 8,000, Tg 65 ° C.,
A9: Byron GK140 (Toyobo Co., Ltd., number average molecular weight 13,000, Tg 20 ° C.

A10 for Comparative Example: Byron GK810 (Toyobo Co., Ltd., number average molecular weight 6,000, Tg 46 ° C.,
A11: Elitel UE3500 (Unitika Ltd.), number average molecular weight 30,000, Tg 35 ° C.,

Chlorinated polyolefin resin C1: Supercron 390S Weight average molecular weight 80,000, chlorine content 36%
C2: Supercron 224H (acrylic modified) Weight average molecular weight 80,000, chlorine content 12.5%
C3: Super Clone 814HS Weight average molecular weight 20,000, chlorine content 41%
C4: Super Clone 360T (urethane modification) Weight average molecular weight 20,000, chlorine content 31%

C6 for Comparative Example: Supercron 223M (acrylic modified) Weight average molecular weight 50,000, chlorine content 5%
C7: Super Clone 803M Weight average molecular weight 160,000, chlorine content 30%
C8: Super Clon 773H Weight average molecular weight 110,000, Chlorine content 32%
C9: Super Clone L206 Weight average molecular weight 9,000, chlorine content 32%
Both are made by Nippon Paper Chemicals Co., Ltd.

Other B1: Amide resin Versamide 744 (Henkel Co., Ltd. Acid value 20 <)
B2: Rosin resin Haritac SE-10 (Harima Co., Ltd.)
B3: Terpene phenol resin YS Polystar N125 (Yasuhara Chemical Co., Ltd.)
B4: Vinyl chloride resin VINNOL E15 / 40A (WACKER, Inc., number average molecular weight 40,000 to 50,000, Tg 69 ° C.)
B5: Epoxy resin 1004 (Mitsubishi Chemical Corporation, number average molecular weight 1,600, Tg 97 ° C.)
B6: Phenolic resin (Hitanol 1140 (Hitachi Chemical Polymer Co., Ltd.))

(2) Dye C1: Solvent Black 29 (Varifast Black 3810
C2: Solvent Black 27 (Varifast Black 3818)
C3: Oil black 860
Both are manufactured by Orient Chemical Industries Co., Ltd.

(3) Leveling agent F1: FZ2123 (Toray Dow Corning Co., Ltd.)
F2: Sylface SAG008 (Shin-Etsu Silicone Co., Ltd.)

(4) Solvent S1: Methyl ethyl ketone 100%
S2: Methyl ethyl ketone / methanol 95/5 (% by weight)
S3: Methyl ethyl ketone / 1,2-dimethoxyethane = 50/50 (% by weight)
S4: Methyl isopropyl ketone / 1,2-dimethoxyethane = 50/50 (% by weight)
S5: Methyl isopropyl ketone / 1,2-dimethoxyethane / methanol =
45/50/5 (wt%)
S6: Methyl ethyl ketone / toluene = 85/15 (% by weight)
S7: Methyl ethyl ketone / ethyl acetate = 90/10 (% by weight)
S8: Ethanol / methyl ethyl ketone = 70/30 (% by weight)
S9: Methyl ethyl ketone / n-butanol 85/15 (% by weight)
S10: Methyl isopropyl ketone / 1,2-dimethoxyethane / methyl cellosolve
45/40/15 (wt%)

[Examples 1-15, Comparative Examples 1-6]
A solution composed of a binder resin, a leveling agent, a pigment, and a solvent in the types and amounts shown in Table 1 was prepared, and filtered through a 1 μm filter to prepare an ink.
In addition to examining the suitability of the prepared ink for ink jet printers (Evaluation 1), using this ink, samples printed on untreated polypropylene and polyethylene films were subjected to a cello tape peeling test (Evaluation 2) and cardboard abrasion test (Evaluation 3). Further, an eraser wear test (Evaluation 4), a hand-rub test (Evaluation 5), and an appearance (Evaluation 6) were conducted. The results are shown in Tables 1-3.

In Examples 1 to 14 and Comparative Examples 1 to 6, the effects of the molecular weight of the thermoplastic polyester resin and the molecular weight and chlorine content of the chlorinated polyolefin resin were examined.
In all the examples, the ink-jet suitability was good, and good results were shown for cardboard abrasion and abrasion resistance.
On the other hand, when the molecular weight of the binder resin is out of the scope of the present invention, in Comparative Examples 1 and 6, the cardboard abrasion and abrasion resistance are weaker than the Examples of the present invention, and in Comparative Examples 2 to 5, the inkjet suitability is poor. In particular, in Comparative Examples 3 to 5, precipitation occurs during operation and nozzle clogging occurs.

Comparative Examples 7 to 10 are cases in which an ink prepared with a thermoplastic polyester resin and a chlorinated polyolefin resin alone was examined. The former had no adhesion, and the latter had adhesion, but the cardboard abrasion or abrasion resistance was insufficient. there were.
Comparative Example 17
JP-A 2010-275467 is a combination of a vinyl acetate copolymer resin by emulsion polymerization and the chlorinated polyolefin resin of the present invention. When the amount of the binder resin is more than 10% by weight, the inkjet suitability is improved. Narrow. In addition, the ink shown in the examples of the present invention was superior in cardboard abrasion and abrasion resistance.

  In Examples 15 to 18 and Comparative Examples 11 to 13, the influence of the blending ratio of the thermoplastic polyester resin and the chlorinated polyolefin was examined. If the blending ratio is out of the range of the present invention, the abrasion and abrasion resistance are weakened. I understand that.

  In Examples 19 to 23 and Comparative Examples 14 to 16, the total amount of binder resin in the ink was examined. When the total binder resin amount exceeds 20% by weight of the present invention, the abrasion resistance is good, but the ink jet aptitude is poor, and when it is lower than 7 wt%, the ink jet aptitude becomes narrow and the wear resistance etc. Since these were inferior to those of the examples, they were not practical in any case.

  Examples 18, 24 to 27 and Comparative Examples 18 to 20 are cases in which the amount of the dye added to the binder resin amount was examined. If the amount of the dye added is less than the range of the present invention, the color tone of the printing becomes thin and looks good. Deteriorate. On the other hand, if the amount is larger than the range of the present invention, the dye will float on the surface of the print film, and if it is rubbed by hand, it will be unclean and unfavorable, and the film will become brittle and wear resistance will deteriorate. In addition, if the amount of dye added is large, ink jet aptitude is also deteriorated.

Examples 28 and 29 are inks prepared by changing the solvent composition of Example 21 to S9 and S10.
The solvent S9 n-butanol and S10 methyl cellosolve have boiling points 10 ° C. or more higher than their respective main solvents and viscosities 1 cp / 20 ° C. or more, and are somewhat improved in abrasion and abrasion resistance than the ink of Example 21. ing. This is probably because the printed dot shape of Example 21 was a flat shape compared to the donut shape.

In Comparative Examples 21 to 28, evaluation was made on a resin other than the present invention and an ink prepared by combining the resin of the present invention and a resin other than the present invention. Although Comparative Examples 21 to 23 are said to have relatively good adhesion to the polyolefin resin substrate, the abrasion and wear resistance were extremely weak.
Comparative Examples 24 and 25 had no adhesion to the polyolefin resin substrate.
Comparative Examples 26 to 28 were combined with the thermoplastic polyester resin or chlorinated polyolefin resin of the present invention, but inks better than the examples of the present invention were not obtained.

Example 30
Using the ink of Example 18, the expiry date was printed on the upper sealed laminated part of the paper milk container whose outermost layer was coated with polyethylene. Although the printed part was rubbed 30 times with a commercially available dragonfly eraser, the printed part remained clearly although it became faint.
Moreover, when it printed on the trunk | drum side wall part of the molding container made from a polypropylene and evaluated similarly, it was the same result as the above.

Further, these print samples were heat-treated on a conveyer at a speed of 30 m / min under the conditions of a blowing flow rate of 80 m ³ / min, a blowing temperature of 700 ° C., a hot air slit of 15 mm length × 2 mm width and a printing part interval of 5 mm.
When the heated sample was evaluated in the same manner, the inks of Example 18 and Comparative Example 17 were not changed at all even after being rubbed 30 times, which seems to be because the adhesion became stronger by heating.

Comparative Example 29
The same evaluation as in Example 28 was performed using the inks of Comparative Examples 1 and 17.
In each case, the ink of Comparative Example 17 was inferior to Example 28, but the heated one showed almost the same result. On the other hand, the ink of Comparative Example 1 was wear resistant even when heated. Was not good.

Claims (5)

In an ink composition for a jet printer containing a binder resin, a leveling agent, a dye and a solvent,
The binder resin is a weight blend of a thermoplastic polyester resin having a number average molecular weight of 8,000 to 25,000 and a chlorinated polyolefin resin having a weight average molecular weight of 10,000 to 100,000 and a chlorine content of 10 to 50% by weight. Ri Na combined in the ratio 7/3 to 3/7, the content of the binder resin is a 7 to 20 wt% in the ink by weight,
The pigment content is 2 to 10% by weight in the ink weight,
The solvent is a mixed solvent, includes a solvent having a boiling point of 110 ° C. or lower and a viscosity of 0.8 cp / 20 ° C. or lower, further having a boiling point of 10 ° C. or higher and a viscosity of 1.0 cp / 20 ° C. or higher. An ink composition for a jet printer for a packaging material having excellent wear resistance, scratch resistance and adhesion, characterized by containing a certain solvent in a proportion of 20% by weight or less in the total solvent .   The ink composition for jet printers for packaging materials according to claim 1, wherein the packaging material is a packaging container having an outermost layer of polyolefin resin.   The ink composition for jet printers for packaging materials according to claim 1 or 2, wherein the thermoplastic polyester resin is a thermoplastic polyester resin having a glass transition temperature of 20 ° C or higher. The ink composition for a jet printer for packaging materials according to any one of claims 1 to 3 , wherein the pigment is an oil-soluble dye and a metal-containing complex salt. A polyolefin resin packaging material printed with the ink composition for a jet printer for packaging material according to any one of claims 1 to 4 , wherein the polyolefin resin packaging material is formed of an outermost layer made of polyethylene or polypropylene. A polyolefin resin packaging material, which is a container, paper container, pouch container, cap or sheet product for heat sealing.