JPS62227786A - Thermal transfer material - Google Patents

Abstract

PURPOSE:To prevent a base film from being broken, prevent foreign matter from adhering to a thermal head and obviate heat loss, by providing a hardened film of a coating material comprising a fluorine-containing monomer having a radical double bond, on the back side of the base film. CONSTITUTION:A hardened film of a coating material comprising a fluorine- containing monomer having a radical double bond is provided on the back side of a base film, in a thermal transfer material comprising a thermally transferable ink layer on the base film. The hardened film, serving as an anti-sticking layer, is provided by hardening a coating material comprising the fluorine- containing monomer and, optionally, other monomer prepolymer, resin or the like by UV rays, electron rays or the like. In use of the thermal transfer material, the base film will not be melted even with an increase in the heating output of a thermal head, adhesion of foreign matter to the head will not occur even in recording for a long period of time, and since heat loss is substantially zero because of the presence of the protective layer, clear printing can be achieved even in the case of high-speed printing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a thermal transfer material. More specifically, the present invention relates to a thermal transfer material that prevents the thermal transfer sheet from being damaged during recording by providing an abrasion-resistant and heat-resistant protective layer on the thermal transfer sheet used for thermal recording.

(Prior Art) With the development of office automation, thermal transfer recording methods have been incorporated into various terminal devices such as facsimiles and printers. This recording method uses heat-melt transfer material coated with heat-melt ink.

A transfer material coated with a heat-sublimable dye is placed on top of a recording paper such as plain paper, and the ink is transferred from the transfer material to the recording paper by heating from a thermal heater to record. . A device that uses a recording needle instead of a thermal radar (for example, Japanese Patent Application Laid-Open No. 5B-220793) or one that uses an electrode terminal (for example, Japanese Patent Application Laid-Open No. 55-1989)
-1'7521) and the like are known.

In the recording method using a thermal head,
・The heat generated from the rad passes through the support and melts the thermal transfer ink, thereby transferring the ink to plain paper, etc., so the ink layer is melted, but the support (base film), which is a plastic film, etc., is not melted. It is necessary. However, in order to speed up recording and record on recording paper with a rough surface, it is possible to increase the amount of heat applied to the thermal head, increase the pressure applied, and make the thermal head more sharply protruding. The amount of heat and pressure applied to the film increases significantly, and the base film is eventually damaged. As a result, if the damaged support adheres to the thermal head, satisfactory recording will not be possible, and troubles such as damage to the head will occur, making it impossible to perform normal recording. This phenomenon is generally called the stick phenomenon.

Furthermore, in the method of using a recording needle or an electrode terminal instead of a thermal head, unlike a thermal head, significant heat is not applied to the base film, but a significant impact is applied due to discharge or current flow phenomena, and there is a risk of damage.

Conventionally, in order to improve this stick phenomenon,
-13359, a method of applying heat-resistant resin etc. to the lower surface of the base film as shown in JP-A-58-187396, JP-A-56-155794, JP-A-59-196291 and Japanese Patent Publication No. 57-7419
No. 5 discloses a method of mixing a lubricant or a surfactant into a photocurable resin and applying the mixture.

Although it is known that it is not satisfactory, products containing lubricants and surfactants are not suitable for long-term recording.

Lubricant or surfactant may adhere to the thermal head.

If a thermal transfer material is stored under high temperature and humidity, problems such as the inability to record properly may occur due to lubricants and surfactants migrating to the ink layer.

(Problems to be Solved by the Invention) As a result of intensive research into a method to improve the above-mentioned drawbacks, the inventors of the present invention have found that the problem of damage to the base film during recording does not occur, and even during long-term recording, foreign particles can be stuck to the thermal head. We have completed a thermal transfer material that does not stick to the ink, can withstand storage under high temperature and humidity, and has an anti-stick layer that does not interfere with the thermal conductivity of the ink layer.

[Structure of the Invention] (Means for Solving the Problems) That is, 9 The present invention provides a thermal transfer material in which a thermal transferable ink layer is provided on a support (base film), in which radicals are added to the back surface of the base film. This is a heat-sensitive transfer material provided with a cured film of a coating containing a fluorine-containing monomer having a polymerizable double bond. Furthermore, a film hardened by active energy rays 1, such as ultraviolet rays or electron beams, is used as a stick prevention layer. The cured film of a coating containing a fluorine-containing monomer having a radically polymerizable double bond is a fluorine-containing monomer having a radically polymerizable double bond, and if necessary, other monomers and a prepolymer. It is a film made by curing a coating containing resin or the like with ultraviolet rays, electron beams, etc.

The fluorine-containing monomer having a radically polymerizable double bond corresponds to what is generally called a monomer. For example, the monomers shown in the following table are used.

(Hereinafter, blank space) One or more of these are used in the present invention.

These monomers may be used in combination with other radically polymerizable double bond-containing monomers, oligomers, and/or prepolymers.

In addition, acrylic resins, polyester resins, melamine resins, epoxy resins, ketone resins, rosin resins, alkyd resins, phenolic resins, silicone resins, cellulose resins such as cellulose acetate butyrate, nitrocellulose, cellulose acetate, vinylidene dung flowers, etc. fluororesin, polyvinyl alcohol resin, urethane resin,
Polysecure resin.

It can also be mixed with resins such as polycarbonate resins, polyimide resins, chlorinated rubbers, cyclized rubbers, and other rubber-based resins. Furthermore, it is also possible to use additives together. In addition, when forming a film using ultraviolet rays, a photopolymerization initiator is usually used. As the photopolymerization initiator, benzophenone type, benzoin type, ketal type, thioxanthone type, anthraquinone type, etc. are generally used. Also,
Electron beams generally do not require a photoinitiator.

A film-forming material containing at least a fluorine-containing monomer having a radically polymerizable double bond, as described above.

A coating coated or printed on a base film by a conventionally known method can be formed into a film by irradiating it with ultraviolet rays, electron beams, or the like. Irradiation conditions may be normal conditions and no special conditions are required.

As the support used in the present invention, a conventionally known base film can be used. Examples include polyester films (polyethylene terephthalate, polyethylene naphthalate, etc.), polyamide films (nylon, etc.), polyolefin films (polypropylene, etc.), cellulose films (triacetate, etc.), polycarbonate films, and the like. Polyester film has heat resistance 1 mechanical strength and tensile strength.

It is most preferred because of its excellent tensile stability. The thinner the support is, the better the thermal conductivity is, but from the viewpoint of strength and ease of application of the ink layer, it is most preferably 3 to 50 microns.

Furthermore, conventionally known inks can be used as they are for the ink layer. As an example of the ink, it is possible to use an ink colored with a dye or a pigment using a wax such as paraffin wax, carnauba wax, Japanese wax, or beeswax as a binder agent.

According to the present invention, an abrasion-resistant and heat-resistant protective layer is provided on the back side of the base film provided with the ink layer.

This protective layer has a thickness of about 0.01 microns to several microns, preferably 0.1 microns to 5 microns.

Hereinafter, the present invention will be explained in detail with reference to Examples.

Note that "parts" in one example are "parts by weight."

(Example) Example 1 Monomer coating liquid A having the following composition was applied to a 6μ polyester film (base film) using a gravure coater so that the dry film thickness was approximately 1μ, and the film was heated in a nitrogen atmosphere. Medium, electrode current 5 mA, acceleration voltage 160 KV, dose I M r
It was cured by irradiation with electron beams a and d, and an ink layer containing carnauba wax as a main component and colored with carbon black was coated on the back side while heating with a bar coater. The thickness of the ink layer was 3.2 μm. On the other hand, a thermal transfer sheet without a protective layer was also prepared in the same manner.

Coating liquid A Monomer No. 1 10 parts Ethyl acetate 50 parts Methyl ethyl ketone 5 parts Comparative example 1 Coating liquid B having the following composition was applied in the same manner as in Example 1, and the other side of the base film dried with hot air was coated with Example A heat-sensitive transfer sheet was prepared by providing the same ink layer as in Example 1.

Coating liquid B Nitrocellulose resin (manufactured by Asahi Denka, alcohol-less NC
H-1/2. ) 50 parts Fluorine surfactant (manufactured by Mitsubishi Metals, EF-103) 1 part Ethyl acetate 25 parts Toluene 25 parts Using the transfer sheets of Example 1 and Comparative Example 1, a printing test was conducted under a thermal hood. .

The printing test was conducted at a constant energy for 10 cycles, with each cycle consisting of one continuous section and a 10 minute pause. The energy level varies from 1.3 mj/dot to 3.0 mj/dot by changing the voltage applied to the thermal head and the pulse. Omj/da
I went to t.

The transfer sheet provided with the protective layer of Example 1 had a density of 1.0 mj/
Even when the energy was increased from dat to 3.0 mj/dat, the printing was not disturbed at all. Furthermore, in a 10-cycle printing test, even with an energy of 3.0 mj/dot, there was no evidence that the base film would fuse to the thermal head or foreign matter would adhere to it.Of course, the base phenol would melt and cause damage. In contrast, the thermal transfer sheet of Comparative Example 1
．． Printing is distorted at 0 mj/dot, 3.0 mj/
The dot caused fusion to the thermal head. Also, with a thermal transfer sheet without a protective layer, printing began to become distorted at 1.2 mj/dot.

At 1 and 3 mj/dot, the base film was fused to the thermal head, and the base film was also damaged and melted. In addition, the thermal transfer sheet of Comparative Example 1 had a heat transfer rate of 1.5 mj/
Although the stick phenomenon did not occur with the energy of dat, a lot of foreign matter adhered to the thermal head during the 10-cycle printing test, resulting in missing prints and the like.

Hereinafter, a protective layer was formed on the base material in the same manner as in Example 1,
A thermal transfer sheet with an ink layer was similarly prepared and compared with a thermal transfer sheet without a protective layer. In addition, in Example 6.7,
Instead of the hot-melt ink containing carnauba wax as a product in Example 1, an ink containing a sublimable dye having a primary composition was applied to a thickness of 2.3 μm using a bar coater, and dried with hot air. A thermal transfer sheet without a protective layer was also made in the same manner.

Sublimation transfer ink composition Kayaset Red B (Nippon Kayaku layer) 10 parts Cellulose acetate propionate 15 parts Silica gel 2 parts Methylolmelamine 1 part Xylene
73 parts In Examples 5 and 6, ultraviolet rays were irradiated instead of electron beams. Irradiation conditions are 80W/
In all of the examples, under a high-pressure mercury lamp of 15 cm, with a surface of 15 cm, and a conveyor speed of 10 m/min, the thermal transfer material provided with a protective layer had poor printability and staining phenomenon on the thermal head.

The adhesion of foreign matter, melting and damage of the base film after printing were significantly better than when no protective layer was provided.

What are the main components of the fluorine-containing monomer coating liquid used for the protective layer?

It is as follows (the diluting solvent is omitted).

Note 1: Terminal acrylic modified polybutadiene (Poly b
d R-458CR, manufactured by Idemitsu Kosan) Note 2: 4,4-bisdiethylaminohenzophenone (The solid content ratio in the table is the solid content ratio after the completion of the curing reaction.) (Effects of the invention) This invention In the thermal transfer material of the invention, the base film does not melt even when the amount of heat from the thermal head is increased.

There is no foreign matter attached to the thermal head even during long-term recording, and there is almost no heat loss due to the protective layer provided, so even if the printing speed is increased, clear printing can be obtained, making it compatible with high-speed printing. It is possible to do so.

(Hereafter, margin)

Claims (1)

[Claims] 1. In a heat-sensitive transfer material in which a heat-transferable ink layer is provided on a base film, a cured film of a coating containing a fluorine-containing monomer having a radically polymerizable double bond is provided on the back surface of the base film. Characteristic thermal transfer material.