JPS62280078A - Production of thermal transfer recording material - Google Patents

Abstract

PURPOSE:To produce a thermal transfer recording material capable of transferring high-quality images, safely, inexpensively and stably, by applying a powdery heat-sensitive ink containing a binder and a coloring agent to a base material and fixing the ink. CONSTITUTION:A powdery heat-sensitive ink 2 obtained by melt-kneading a noncrystalline aromatic polyester, an ester wax and carbon black is supplied from a powdery ink supplying part 6 to a coating nozzle 5 provided at an upper part of a coating chamber 3, and is electrified in the nozzle 5 by electric discharge effected by a corona electrode supplied with a high voltage from a high-voltage power source 7. The ink 2 is dispersed in the chamber 3 by electrostatic repulsive forces acting between the particles thereof, while dropping, and is uniformly adhered by electrostatic forces to the base material 1 moved on a counter electrode 4 to form a substantially single layer. The ink 2 on the base material 1 is melted by heating by an IR heater, thereby fixing the ink on the base material.

Description

DETAILED DESCRIPTION OF THE INVENTION 3. Detailed Description of the Invention Field of Industrial Application The present invention relates to a method for producing a novel thermal transfer recording material.

Conventional technology Conventionally, methods for producing thermal transfer recording materials include the so-called hot-melt coating method, in which heated and melted thermal ink is applied to the top surface of a base material being transported, and the thermal ink is made into a solution using an appropriate solvent. The so-called solvent coating method is well known.

Problems to be Solved by the Invention However, in the hot melt coating method, it is difficult to precisely control the melt viscosity of the thermal ink, so it is difficult to thin the thermal ink layer, and it also causes uneven coating and coloring of the thermal ink. It has disadvantages such as causing poor dispersion of the agent, and
Manufacturing costs also increase because energy is required to melt the ink.

It is also difficult to apply thin layers of highly viscous materials. On the other hand, the solvent coating method uses a large amount of organic solvent, which inherently poses safety issues, and requires a drying process, so the manufacturing equipment is larger than that of the hot melt coating method. However, it has disadvantages such as high cost.

Therefore, in view of the drawbacks of the conventional coating method, the present invention provides:
An object of the present invention is to provide a method for safely, inexpensively, and stably producing a heat-sensitive transfer recording material that provides a high-quality transferred image.

Means and effects for solving the problems, that is, the method for producing a thermal transfer recording material of the present invention differs from the conventional coating method described above, in that it contains a binder and a colorant as essential components, and melts and melts by heating. The method is characterized in that a powdered thermal ink having heat-sensitive changeability such as sublimation is deposited on a base material, and the deposited thermal powder ink is fixed on the base material.

Next, the content of the technology of the present invention will be explained in more detail.

The powder thermal ink used in the present invention contains a binder and a colorant as essential components, and other additives are added as necessary, and the ink melts and/or sublimates when heated. There are no particular limitations on the composition or material as long as it shows a change in physical properties.

As the binder, various thermoplastic resins and waxes can be used, similar to toners used in electrophotography and electrostatic recording.

For example, styrene resin, acrylic resin, polyester, polyamide, polycarbonate, polyurethane, silicone resin, fluororesin, epoxy resin, petroleum resin, rosin, rosin modified resin, olefin resin such as polyethylene, polypropylene, paraffin, carnauba wax, Ester wax, microcrystalline wax, higher fatty acids such as stearic acid and esters of higher fatty acids,
Natural and synthetic resins, waxes, etc. such as derivatives such as amides and metal salts can be used. These can be used alone or as a mixture as a binder, and can also be used as a copolymer as well as a homopolymer. If necessary, softeners, plasticizers, reinforcing agents, antistatic agents, mold release agents,
Additives such as foaming agents and surfactants may also be added.

It is also possible to produce a heat-sensitive transfer recording material for color recording by appropriately selecting a colorant made of dyes and pigments. For example, black dyes and pigments such as oil black, graphite, and carbon black, C, 1,61505,C
, 1,64500, C.

1.74160. C,1,74200,C,I.

Red dyes such as C and I shown as 74250.

11110,,C,1,11115,C,I.

11210,C,1,12120,C,I.

12135, C, 1, 12490, C, I.

15585, C, 1, 15850, C, I.

15880, C, 1, 21120, C, I.

45150, C,1,60755, etc.; C,1,10338, C,I.

10345, C, 1, 11680S C, I.

11710, C, 1, 11855, C, I.

12712, C, 1, 12790, C, I.

21090,C,1,21095,C,I.

Yellow dyes and pigments such as 21100, C, 1, 26090, etc. can be used.

The powder thermal ink used in the present invention may be produced by any method, for example, by melting and mixing a binder, a colorant, and other additives as necessary, and then pulverizing them; It can be manufactured by making the composition into a solution or dispersion and then synthesizing it by a spray drying method or directly by emulsion polymerization, dispersion polymerization, suspension polymerization, etc.

Furthermore, if necessary, the heat-sensitive powder ink may be classified to adjust the particle size.

Furthermore, the base material used in the present invention is not particularly limited in terms of composition and material, and base materials conventionally used in thermal transfer recording materials such as capacitor paper, polyester film, and polyimide film can be suitably used as they are. .

In the present invention, the powder coating method of applying the heat-sensitive powder ink onto the base material includes an electrostatic powder coating method of applying a charged powder-like heat-sensitive ink to a coating having electrically opposite polarity; An electrostatic powder coating method that is an application of the dry or wet development method used in electrophotographic electrostatic recording can be used.

In addition, no special driving force is used to move the powdered thermal ink onto the base material, and the powdered thermal ink, which has become a mist due to air flow, is simply dropped onto the base material by gravity and applied. It is also possible to do so.

Conventionally, in the electrostatic powder coating method, the minimum coating thickness is about 50 μm, but in the present invention, the particle size of the powdered thermal ink is 0.1 μ'rrL to 20 μm, and the powder is coated on the base material. The coating amount was adjusted so that the heat-sensitive ink layer was coated with a thickness of 0.5 μ7 rL.
~20 μm 1 preferably 1 μTrL ~ 10 μm.

Next, the applied powder thermal ink is heated by a heating means such as a heat roller, a flash lamp, an infrared lamp, etc.
A heat-sensitive transfer recording material can be produced by fusing it to a base material or by fixing it to a base material using pressure or some solvent vapor.

Of course, it is possible to electrostatically hold the powdered thermal ink on the base material without adopting a special fixing process, or to hold it on the base material with adhesive. From the point of view of stability and reliability, it is necessary to establish the system.

In addition, in the present invention, two or more types of powdered thermal inks having different thermal properties, rheological properties, surface chemical properties, and physical and chemical properties are discontinuously and uniformly applied to the base material using independent rollers. Alternatively, two or more powdered thermal inks having different particle sizes, tones, and densities may be applied as independent dots and fixed to produce a multifunctional thermal transfer recording material.

Furthermore, the above-mentioned two or more powdered thermal inks with different characteristics are separately applied in multiple layers in a laminated manner on a base material, and fixed, thereby providing a multifunctional feel in which the ink characteristics of each layer are controlled separately. A thermal transfer recording material may also be created.

EXAMPLES Hereinafter, the present invention will be explained by examples, but it goes without saying that the present invention is not limited to these examples.

(Manufacture of powder thermal ink) Amorphous aromatic polyester 50 parts by weight (approx. 50°C before glass transition) Ester wax 5 parts by weight (melting point 76°C) Carbon black 10 parts by weight Melt-knead the above composition. , pulverized and classified to obtain particles with an average particle size of 7 μm. Furthermore, 1.0% hydrophobic colloidal silica is added to these particles.
A powdered thermal ink was obtained by adding % by weight and mixing in a V-blender.

(N) The drawings show an example of an apparatus for carrying out the present invention.

A predetermined amount of the powdered thermal ink 2 described above is supplied from the powder ink supply section 6 to the coating nozzle 5 provided at the top of the coating chamber 3, and inside the coating nozzle 5, a high voltage is supplied from the high voltage power supply section 7. It was charged by corona discharge using a corona electrode (not shown) to which a voltage was applied. Powdered thermal ink 2
are dispersed in the coating chamber 3 due to mutual electrostatic repulsion, fall, and are uniformly coated onto the base material (9μ thick PET film) 1 moving on the grounded counter electrode 4 due to the electrostatic force. It adhered to the surface in almost a layer.

Next, the powdered thermal ink 2 on the base material 1 is heated and melted using an infrared heater (not shown) and fixed on the base material, thereby producing a thermal transfer recording material having a thermal ink layer approximately 4 μm thick. 〇 - I did.

It was confirmed by transmission electron microscopy that the carbon black in the fixed heat-sensitive ink layer was well dispersed.

In addition, when we conducted a thermal transfer recording test using this thermal transfer recording material using a Fuji Xerox model P-6 thermal transfer printer, we found that it had excellent resolution for kanji characters, etc., and had good gradation with respect to the thermal head printing energy. It was confirmed that a transferred image having a certain quality can be obtained.

Example 2 Powdered thermal ink deposited on a base material in the same manner as in Example 1 was dissolved with a small amount of solvent (1,1,1-trichloroethane) vapor and fixed on the base material to produce thermal transfer recording. manufactured the material.

It was confirmed that this heat-sensitive transfer recording material also had good dispersion of carbon black as in Example 1, and provided a transferred image with excellent resolution and gradation.

Effects of the Invention As explained above, in the present invention, unlike conventional techniques, the heat-sensitive ink layer of the heat-sensitive transfer recording material is formed by a powder coating method using powdered heat-sensitive ink, so that the present invention has the following advantages. . In other words, since it does not use a large amount of solvent, it does not pollute the environment, there is no need for a drying process, and since it uses powdered thermal ink, it is easy to collect and reuse the ink. , it is possible to reduce the cost to 1 or less. Furthermore,
By selecting the particle size of the powdered thermal ink, thin layer coating, which is difficult with hot melt coating methods, becomes possible.

Furthermore, it becomes possible to apply an ink layer with high melt viscosity.

Furthermore, when fixing the powder thermal ink on the base material,
By controlling the fixing conditions, it is possible to form a patterned discontinuous ink layer on the drum that retains the initial powder shape, or to form a continuous ink layer that does not retain the initial powder shape. It is also possible to form Therefore, it is extremely effective in improving the resolution and gradation reproducibility of thermal transfer recording.

In addition, when two or more types of powder heat-sensitive inks with different properties are used, they can be applied as individual dots and fixed, or they can be applied in multiple layers.
By fixing, a multifunctional heat-sensitive transfer recording material can be easily produced.

As described above, the present invention has many advantages over conventional coating methods, and can stably produce a thermal transfer recording material that provides a high-quality transferred image safely and at low cost.

[Brief explanation of the drawing]

The drawing is a schematic configuration diagram of an apparatus for carrying out the present invention. 1...Base material, 2...Powdered thermal ink, 3...
- Coating chamber, 4... Counter electrode, 5... Coating nozzle, 6... Powder ink supply section, 7... High voltage power supply section.

Claims (1)

[Claims] A method for producing a thermal transfer recording material, which comprises depositing a powdery thermal ink containing a binder and a colorant onto a base material, and fixing the deposited powdery thermal ink onto the base material.