JPH10158559A - Heat sensitive ink roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat sensitive ink roll for a hot type printer capable of providing an image excellent in thermal stability by using an ink having a specified melt-starting temperature, melting temperature and viscosity as a heat-meltable ink to be impregnated into a roll-like continuously porous body. SOLUTION: This heat sensitive ink roll is constituted of a roll-like continuously porous body and an impregnated heat-meltable ink comprising a vehicle and a coloring agent. The heat meltable ink has >=80 deg.C melt-starting temperature, >=120 deg.C melting temperature and 10-1,500cps viscosity at 160 deg.C. The vehicle preferably includes 75-90wt.% N-substituted fatty acid amide or N-substituted aromatic carboxylic acid amide having >=120 deg.C melting point and >=80 deg.C melt- starting temperature. For example, N,N'-ethylenebislauric acid amide is exemplified as the amide. The content of the coloring agent in the ink is preferably 5-20wt.%. For example, an open cell body of a polyurethane rubber is used for the roll-like continuously porous body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive ink roll in which a hot-melt ink is impregnated in a roll-shaped continuous porous body.

[0002]

2. Description of the Related Art Conventionally, a heat-sensitive ink roll impregnated in a roll-shaped continuous porous body with a hot-melt ink has been heated to exude the hot-melt ink and adhere to a type body of a thermal type printing machine. With this typeface, imprints of characters, symbols, and the like are formed on packaging materials and the like.

[0003] As a hot-melt ink to be impregnated, a mixture of a vehicle composed of wax, ethylene-vinyl acetate resin, a tackifier and the like, and a pigment and a dye for complementary color has been conventionally used.

[0004]

However, the heat-meltable ink has a melting start temperature of about 40 to 70 ° C. and a melting point of about 70 to 100 ° C., and has poor heat resistance. Therefore, there were the following problems.

[0005] For example, when printing is performed on a package of food or the like, the printing is performed by installing a printing machine on a packaging line. When a heat-sensitive ink roll impregnated with an inferior ink is used, if printed characters are rubbed, there is a problem that the packaging material becomes dirty, and the characters and the like become unreadable.

[0006] In addition, since retort foods and the like are subjected to heat sterilization in the manufacturing process, they cannot be printed using a conventional heat-sensitive ink roll.

The present invention has been made in view of the above circumstances, and provides a thermal ink roll which has solved the problem of poor heat resistance of a printed image, which is a drawback of the conventional thermal ink roll.

[0008]

According to the present invention, there is provided (1) a heat-sensitive ink roll in which a roll-shaped continuous porous body is impregnated with a heat-meltable ink comprising a vehicle and a colorant; Is 80 ° C. or higher and the melting point is 12
0 ° C. or higher and a viscosity at 160 ° C. of 10 to 150
The present invention relates to a heat-sensitive ink roll characterized by being 0 cps.

Further, the present invention is characterized in that (2) the vehicle contains 75 to 90% by weight of an N-substituted fatty acid amide or an N-substituted aromatic carboxylic acid amide having a melting point of 120 ° C. or higher. A heat-sensitive ink roll according to claim 1.

Here, the melting start temperature is a temperature at which a differential scanning curve starts to shift from a position on a base line to an endothermic side when measured using a differential scanning calorimeter, and the melting point is a temperature of a peak on the endothermic side. It is.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides a hot-melt ink comprising a vehicle and a colorant impregnated in an ink roll.
The present invention is characterized in that a material having a melting start temperature of 80 ° C. or higher and a melting point of 120 ° C. or higher is used, thereby improving the heat resistance of a printed image and solving the problem.

Further, the viscosity of the ink is defined at a temperature of 160 ° C. in the range of 10 to 1500 cps in consideration of the printing life and the impregnation property of the roll.

When the melting point of the hot-melt ink is lower than 120 ° C., in a retort food or the like, since the heat sterilization treatment is usually performed with pressurized steam at about 120 ° C., the printed image is dissolved.

When the melting start temperature of the hot-melt ink is less than 80 ° C., the printed image may be stained or disappeared when rubbed under the environmental temperature increased by the heat generated by the heat sealing portion on the packaging line. I do.

Regarding the viscosity of the ink, if the viscosity is less than 10 cps at 160 ° C., the printing life is shortened because the ink is excessively supplied at the time of printing, while if it exceeds 1500 cps, it is difficult to impregnate the continuous porous body. Become.

In the present invention, as a vehicle component of the hot-melt ink, an N-substituted fatty acid amide or an N-substituted aromatic carboxylic acid having a melting point of 120 ° C. or more, more preferably 80 ° C. or more is preferred. Acid amides can be preferably used. Such N-substituted fatty acid amides or N-substituted aromatic carboxylic acid amides include N,
N'-methylene bis long chain aliphatic monobasic acid amide, N,
N′-alkylene bis long chain aliphatic monobasic acid amide, N,
N′-aralkylenebis long-chain aliphatic monobasic acid amide,
N, N'-di-long-chain alkylaliphatic dibasic amides,
N'-di-long-chain alkyl aromatic dibasic acid amides, and specifically, for example, N, N'-ethylenebislauric acid amide, N, N'-methylenebisstearic acid amide, N, N'-ethylene Bisstearic acid amide, N,
N'-ethylenebisbehenamide, N, N'-ethylenebis-12-hydroxystearic acid amide,
N'-butylenebisstearic acid amide, N, N'-hexamethylenebisstearic acid amide, N, N'-hexamethylenebisoleic acid amide, N, N'-xylylenebisstearic acid amide, N, N'- Hexamethylenebis-12-hydroxystearic acid amide, N, N '
-Xylylenebis-12-hydroxystearic acid amide, N, N'-distearyladipamide,
N'-distearyl sebacic amide, N, N'-distearyl terephthalic amide, N, N'-distearyl isophthalic amide and the like can be mentioned. These N-substituted fatty acid amides or N-substituted aromatic carboxylic acid amides can be used alone or in combination of two or more.

The content of the N-substituted fatty acid amide or N-substituted aromatic carboxylic acid amide in the vehicle is preferably 75 to 90% by weight. When the content of the N-substituted fatty acid amide or N-substituted aromatic carboxylic acid amide in the vehicle is less than 75% by weight, the viscosity at 160 ° C. of the ink is set to 1500 cps or less, and the melting point is maintained at 120 ° C. or more. Can no longer be used, while 90
If the amount is more than 10% by weight, the viscosity of the ink becomes less than 10 cps, and the printing life tends to be shortened because the ink is excessively supplied at the time of printing.

In the present invention, as a vehicle component other than the N-substituted fatty acid amide or the N-substituted aromatic carboxylic acid amide, a thermoplastic resin and / or wax is blended, and the melting start temperature, melting point and viscosity of the ink are increased. Can be adjusted.

The thermoplastic resin includes polyamide resin, polyester resin, ethylene-vinyl acetate copolymer, polyethylene, polyurethane, polyvinyl alcohol, acrylate resin, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer. Polymers, epoxy resins and the like can be used.

As the wax, polyethylene wax, chlorinated polypropylene wax and the like can be used.

Examples of the colorant for the hot-melt ink include carbon black, azo pigments (insoluble azo, azo lake, and condensed azo pigments), phthalocyanine pigments, nitro pigments, nitroso pigments, anthraquinone pigments, and nigrosine pigments. Pigments, quinacridone pigments, perylene pigments,
Various organic and inorganic pigments such as isoindolinone pigments and dioxazine pigments can be used. To adjust the color tone,
You may use a dye together. The content of the colorant in the ink is suitably about 5 to 20% by weight.

The hot-melt ink may contain a dispersant, a tackifier resin and the like in addition to the above components.

The hot-melt ink can be prepared by uniformly melting and mixing the above components with a kneader such as a roll mill.

In the present invention, as the continuous porous body impregnated with the hot-melt ink, for example, a continuous foam such as polyurethane rubber, silicone rubber, acrylonitrile-butadiene rubber can be used.

[0025]

Next, the present invention will be described with reference to examples and comparative examples.

Example 1 The following materials were prepared using an oil circulation heating type three-roll mill.
A hot melt ink was prepared by kneading at 0 ° C. The obtained ink was impregnated into a roll made of a continuous foam of polyurethane rubber to obtain an ink roll.

Ingredients Parts by weight Loxamid EBS 74 (ethylene bisstearic acid amide, melting temperature 127 ° C., melting point 140 ° C., Henkel Hakusui Co., Ltd.) Versamide 335 15 (polyamide resin, Henkel Hakusui Co., Ltd.) PRINTEX 25 10 (Carbon Black, Degussa) Solsperse 24000GR (Dispersant, Zeneca) 1 Physical properties of the obtained ink are shown below.

Melting onset temperature: 85 ° C. Melting point: 130 ° C. Melt viscosity: 115 cps (160 ° C.) Melting onset temperature and melting point are measured at a heating rate of 10 ° C./min using a differential scanning calorimeter DSC210 manufactured by Seiko Instruments Inc. did. The viscosity is measured by Rheometer MR- manufactured by Rheology Inc.
It was measured at 300.

Using the obtained ink rolls, printing was performed on a packaging material (polyethylene terephthalate film (PET) film) at a temperature of 150 ° C. using a thermal type printing machine, and the following test was performed. went.

<Heat Resistance Test> The same packaging material was superimposed on the printed surface of the packaging material (PET film) and stored in pressurized steam at 120 ° C. for 30 minutes, and the transfer of the ink was visually determined. Table 1 shows the results. In Table 1, ○ indicates that there is no transfer of the printed characters, Δ indicates that the character is shifted but readable, X indicates that the character is completely shifted and cannot be read, and-indicates that no evaluation was made.

<Print life test> Packaging material (PET film)
Was printed 15,000 times, and the density of the print every 1000 times was visually determined. Table 2 shows the results. In addition,
In Table 2, .largecircle. Indicates that the print was clear, .DELTA. Indicates that the print was somewhat unclear but readable, X indicates that the print was unclear and unreadable, and-indicates that no evaluation was made.

Comparative Example 1 An ink was prepared in the same manner as in Example 1 using the following materials, and an ink roll was manufactured using the same material as in Example 1. The same test as in Example 1 was performed. The results are shown in Tables 1 and 2.

Component Weight part HNP-10 50 (paraffin wax, melting start temperature 45 ° C., melting point 77 ° C., Nippon Seiro Co., Ltd.) Polywax # 65510 (polyethylene wax, melting start temperature 60 ° C., melting point 85 ° C.) Evaflex 31025 (ethylene-vinyl acetate copolymer resin, Mitsui / Dupont Polychemical Co., Ltd.) PRINTEX 25 15 The physical properties of the obtained ink are shown below.

Melting start temperature: 38 ° C. Melting point: 75 ° C. Melt viscosity: 370 cps (160 ° C.) Comparative Example 2 An ink was prepared in the same manner as in Example 1 using the following materials, and then used in the same manner as in Example 1. An ink roll was manufactured and tested in the same manner as in Example 1. The results are shown in Tables 1 and 2.

Component parts by weight Loxamid EBS 89 PRINTEX 25 10 Solsperse 24000GR 1 The physical properties of the obtained ink are shown below.

Melting start temperature: 80 ° C. Melting point: 135 ° C. Melt viscosity: 8 cps (160 ° C.) Comparative Example 3 An ink was prepared in the same manner as in Example 1 using the following materials, and was used in the same manner as in Example 1 using the same. When an attempt was made to manufacture an ink roll, it was difficult to impregnate the continuous foam with the ink, so the manufacture of the ink roll was stopped.

Component parts by weight Loxamid EBS 74 DPX 927 15 (polyamide resin, Henkel Hakusui Co., Ltd.) PRINTEX 25 10 Solsperse 24000 GR 1 The physical properties of the obtained ink are shown below.

Melting start temperature: 133 ° C Melting point: 155 ° C Melt viscosity: 1760 cps (160 ° C)

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

According to the thermal ink roll of the present invention,
The melting point and melting start temperature of the impregnated hot-melt ink are about 50 ° C higher than the conventional products, respectively.
The present invention can be used for printing on packaging of retort foods and the like, and the problem that the printing is stained or disappears on the packaging line in the case of the conventional product can be solved.

Claims (2)

[Claims] 1. A heat-sensitive ink roll in which a roll-shaped continuous porous body is impregnated with a hot-melt ink comprising a vehicle and a colorant, wherein the hot-melt ink has a melting start temperature of 80 ° C.
A heat-sensitive ink roll having a melting point of 120 ° C. or higher and a viscosity at 160 ° C. of 10 to 1500 cps. 2. The method according to claim 1, wherein the vehicle contains 75 to 90% by weight of an N-substituted fatty acid amide or an N-substituted aromatic carboxylic acid amide having a melting point of 120 ° C. or higher. Thermal ink roll.