JPS63203386A - Thermal transfer material - Google Patents

Abstract

PURPOSE:To prevent a thermal transfer sheet from being broken during recording, by providing a hardened coat film obtained by a reaction of a silicone oil having an amino group in the molecule thereof with a polyisocyanate compound, on the back side of a base film. CONSTITUTION:A silicone oil having an amino group in the molecule thereof may be, for example, a silicone oil in which an amino group or an amino- containing organic group is introduced into a part of methyl groups in a dimethylpolysiloxane. A mixture of the silicone oil and a polyisocyanate is applied to a base, and the coat film thus obtained is hardened under ordinary heating conditions. The heating conditions depend on the number of functional groups or the presence or absence of a catalyst, and can not be indiscriminately specified, but usually, the hardening is conducted at 120-80 deg.C for 30-60sec. A hardened coat film may also be provided by aging the coat film at a temperature of 40 deg.C-room temperature for 1-3 days.

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 ink is transferred from the transfer material to the recording paper by heating from a thermal head to perform recording. Those that use a recording needle instead of a thermal head (for example, JP-A-58-220793 II) or those that use electrode terminals (for example, JP-A-58-220793)
5-17521) and the like are known.

In the recording method using a thermal head, the heat generated from the thermal head passes through the support and melts the thermal transfer ink, thereby transferring the ink to plain paper etc.
It is necessary to melt the ink layer but not to melt the support (base film), such as a plastic film. However, in order to speed up recording or record on recording paper with a rough surface, the amount of heat applied to the thermal head can be increased, the pressure applied can be increased, and the thermal head can be made to have a sharper, more prominent structure.

The amount of heat and pressure applied to the base film increases significantly,
As a result, the base film is damaged. As a result, if the damaged support adheres to the thermal head, satisfactory recording will not be possible, and troubles such as head breakage will occur, making normal recording impossible. This phenomenon is generally called the stick phenomenon.

Further, 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, which may cause damage.

Conventionally, in order to improve this stick phenomenon,
A method of applying a heat-resistant resin or the like to the lower surface of the base film as shown in JP-A No. 13359 and JP-A-58-187396; Kaisho 57-74195
The publication describes a method in which a lubricant or surfactant is mixed into a photocurable resin and then applied.

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, one aspect of the present invention is a heat-sensitive transfer material in which a heat-transferable ink layer is provided on a support (base film).

This heat-sensitive transfer material is characterized in that a cured coating formed by reacting a silicone oil containing an amino group in one molecule with a polyvalent isocyanate compound is provided on the back surface of the base film.

The silicone oil containing an amino group in the molecule in the present invention is, for example, a silicone oil in which an amino group or an organic group having an amino group is introduced into a part of the methyl group of dimethylpolysiloxane.

(In the formula, R represents a CH3 group or an OCR group, and n and m represent an integer of 1 or more.)

A polyvalent isocyanate compound is a compound having two or more isocyanate groups, such as phenylene diisocyanate), 2.4-) lylene diisocyanate 1-.
2.6-) Riene diisocyanate.

l-chloro-2,4-phenyl diisocyanate.

2-chloro-1,4-phenyl diisocyanate.

4.4'-diphenylmethane diisocyanate.

Dianisidine diisocyanate, metaxylene diisocyanate, hexamethylene diisocyanate.

1. Diisocyanates such as 5-naphthalene diisocyanate, triisocyanates such as triphenylmethane triisocyanate, the reaction product of 1 mole of trimethylolpropane and 3 moles of tolylene diisocyanate, urethane prepolymers such as polytetramethylene ether glycol and 4,4' - There are prepolymers obtained by an equivalent reaction product of diphenylmethane diisocyanate.

After mixing the above-mentioned silicone oil and polyvalent isocyanate and applying the mixture to a substrate, the coating film is cured under normal heating conditions. Heating conditions cannot be specified because they vary depending on the number of functional groups and the presence or absence of a catalyst, but curing is usually carried out at 120 to 80°C for 30 to 60 minutes.

Moreover, a cured coating film can also be formed by aging at about 40° C. to room temperature for about 1 to 3 days.

In addition, if necessary, acrylic resin, polyester resin,
Melamine resin, epoxy resin, ketone resin.

Rosin resin, alkyd resin, phenolic resin, cellulose acetate butyrate, nitrocellulose.

Resins such as cellulose resins such as cellulose acetate, fluororesins such as vinylidene fluoride, polyvinyl alcohol resins, urethane resins, polyacecool resins, polycarbonate resins, polyimide resins, polyvinylcarbazole resins, rubber resins such as chlorinated rubber, cyclized rubber, etc. It can also be used in combination with a small amount.

Furthermore, it is also possible to use additives together.

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

This support is most preferable because of its excellent tensile stability, etc. The thinner the support is, the better its thermal conductivity is, but it is most preferably 3 to 50 μ from the viewpoint of strength and ease of coating the ink layer. Furthermore, conventionally known inks can be used as they are for the ink layer. As an example of such an ink, an ink colored with a dye or a pigment may be used, using a wax such as paraffin wax, carnauba wax, Japanese wax, or beeswax as a binder agent.

In the present invention, the protective layer provided on the back side of the support is approximately 0.0
The thickness is 1 μ to several μ, preferably 0.1 μ to 5 μ.

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

Note that "parts" in the five examples are "parts by weight."

(Example) Example 1 A coating liquid with the following composition was applied to a 6μ polyester film (support) using a gravure coater so that the dry film thickness was approximately 1μ, and heated at 80°C for 1 hour. This was cured to form a protective layer, and an ink layer containing carnauba wax as a main component and colored with carbon black was applied to the back surface of the protective layer using a bar coater while heating. 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.

Ryomin modified silicone oil (KF861 manufactured by Shin-Etsu Chemical Co., Ltd.) 10 parts aliphatic polyisocyanate (Sumidur N-75 manufactured by Sumitomo Bayer Urethane Co., Ltd.) 1 part toluene
30 parts Methyl ethyl ketone 30 parts Comparative Example 1 A coating liquid with the following composition was applied in the same manner as in Example 1, and the same ink layer as in Example 1 was provided on the other side of the base film that was dried with hot air to create a thermal transfer sheet. .

Nitrocellulose resin (manufactured by Asahi Denka, alcohol-free NC
H-1/2) 50 parts ethyl acetate 25 parts toluene
25 parts Example 1 and Comparative Example 1
A printing test was conducted using a thermal head using the transfer sheet.

The printing test was conducted at a constant energy for 10 cycles, each cycle consisting of 10 minutes continuous and 10 minutes pause.

Change the energy level by changing the voltage and pulse width applied to the thermal head], from 3 o + j / dot to 3. Q
I went to mj/dot.

The transfer sheet provided with the protective layer of Example 1 was 1.00w3/
Even when the energy was increased from dot to 3.00 mj/dot, the printing was not disturbed at all. Furthermore, in a 10-cycle printing test, even with an energy of 3.0 On+j/dat, no fusion of the base film to the thermal head or adhesion of foreign matter was observed at all. Of course.

No melting and damage of the base phenol was observed. On the other hand, the thermal transfer sheet of Comparative Example 1 was 2. Printing is distorted at Omj/dat, 3.00m
j/dot caused fusion to the thermal head. In addition, with a thermal transfer sheet without a protective layer, printing was irregular at 1.2 mj/dot, and at 1.3 mj/dot, the base film was fused to the thermal head, and the base film was also damaged and melted. Ta. Further, in the thermal transfer sheet of Comparative Example 1, the stain phenomenon did not occur at an energy of 1°5 mj/dat, but in a 10-cycle printing test, a large amount of foreign matter adhered to the thermal head, and printing omissions occurred.

Example 2 A protective layer was formed in the same manner as in Example 1 using a coating liquid having the following composition.

Amino modified silicone oil (KF862 manufactured by Shin-Etsu Chemical Co., Ltd.) 10 parts Aliphatic polyisocyanate (Sumidur N-75 manufactured by Sumitomo Bayer Urethane Co., Ltd.) 2 parts Toluene
30 parts Methyl ethyl ketone 30 parts Example 3 A protective layer was formed in the same manner as in Example 1 using a coating liquid having the following composition.

Amino-modified silicone oil (X-22-161A manufactured by Shin-Etsu Chemical) 10 parts Aliphatic polyisocyanate (Sumidur N-75 manufactured by Sumitomo Bayer Urethane) 1 part nitrocellulose 1 part toluene
30 parts methyl ethyl ketone 20 parts ethyl acetate
10 parts However, instead of the heat-melting ink containing carnauba wax as the main component in Example 1, an ink containing a sublimable dye having the following composition was applied to a thickness of 2.3 μm using a bar coater, and heated with hot air. It was dried. A thermal transfer sheet without a protective layer was also made in the same manner.

Sublimation transfer ink composition Kayaset Red B (manufactured by Nippon Kayaku) 10 parts cellulose acetate propionate) 15 parts silica gel 2 parts methylolmelamine 1 part xylene
In all 73 examples, the thermal transfer material provided with the protective layer had poor printability and stickiness to the thermal head.

Adhesion of foreign matter, melting of the base film after printing.

The damage condition was significantly better than that without the protective layer.

〔Effect of the invention〕

In the thermal transfer material of the present 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 suitable for high-speed printing. It is possible to respond.

Claims (1)

[Claims] 1. A heat-sensitive transfer material with a heat-transferable ink layer provided on a base film, in which a cured coating is provided on the back surface of the base film, which is made by reacting a silicone oil containing an amino group in the molecule with a polyvalent isocyanate compound. A heat-sensitive transfer material characterized by: