JPS6351182A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To obtain a sharp and high-density transfer image even on a plain paper used as a paper to be transferred, by containing a specific polyester resin as a hot-melt binder. CONSTITUTION:A thermal transfer recording medium is formed, by a method wherein binder components containing a polyester resin and a coloring material are melted and mixed or alternatively dissolved or dispersed together with various additives, if necessary, in an appropriate solvent, and the obtained material is coated on a substrate. The polyester resin in use has 18-260 hydroxyl value. If the hydroxyl value is less than 18, an image is tansferred without sharpness; if more than 260, the possibility of ground foulings in a transferred image is increased and the shelf stability is deteriorated. The polyester resin contained 90-100 wt% in the hot-melt binder is a reaction product of dicarboxylic acid components and glycol components, and an aliphatic dicarboxylic acid is contained 100-70 mol% in the dicarboxylic acid components.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a thermal transfer recording medium that can use plain paper as a transfer material, and more particularly to a thermal transfer recording medium that can transfer even to paper with a rough surface.

[Conventional technology]

Conventionally, thermosensitive coloring paper has been used as a bundle in a method of obtaining a recorded image according to recording information by thermal operation. This thermosensitive coloring paper is generally recorded using a reaction in which a colorless leuco dye and a color developer such as a phenol compound are heated and melted to form a color.

However, this thermosensitive coloring paper tends to cause unnecessary color development during manufacturing and storage, and the recorded images are discolored by organic solvents, heat, light, etc., resulting in poor storage stability and problems in practical use. be.

As a recording method to improve these drawbacks, a heat-melt heat-sensitive transfer recording medium was used, in which a heat-melt heat-sensitive transfer recording layer formed by dispersing a coloring material (i.e., a pigment or dye) in a heat-melt binder was provided on a sheet-like substrate. Recording methods have begun to be used in recent years.

In this recording method, the thermal transfer recording layer of the thermal transfer recording medium and the transferred material are brought into contact with each other, and a pulsed current is applied from the back side of the thermal transfer recording medium to perform heating printing with a thermal head. The binder layer is transferred to the material to be transferred, and a transferred image is obtained.

The heat-sensitive transfer recording medium that has been commonly used in this method uses wax as a heat-melting binder in the transfer recording layer. However, in a thermal transfer recording medium using Wakunu as a binder, in order to obtain an acceptable transfer image, it is necessary to use a flat material as the transfer material. If degree 250
Paper with a particularly smooth surface must be used ((smoothness - Japanese Industrial Standards P8119), or ordinary plain paper/? - paper for copying (smoothness less than 100 seconds)
When using +5, the transfer of thermal transfer ink was not sufficient,
No excellent transferred image was obtained.

In order to solve these problems, we have created a special sticker e11j.

Attempts to improve the body have been proposed, for example, a method using a resin with a softening temperature of 60-110°C (Japanese Patent Laid-open No. 54
-163044), method of using raw rubber in the color material layer (
JP-A-60-135290) and the like have been proposed.

However, even these thermal transfer recording media have a smoothness of 100.
A clear image could not be obtained with paper of less than 2 seconds, and it was still insufficient to use plain paper for general office use as a transfer medium.

(Problems to be Solved by the Invention) Therefore, the problem is to provide a thermal transfer recording medium that can provide a clear, high-density transferred image even when plain paper with a smoothness of less than 100 seconds is used as the transfer paper. It's about doing.

(Means for Solving the Problems) The present invention provides a heat-sensitive transfer recording medium in which a heat-sensitive transfer recording layer containing a coloring material in a heat-melting binder is provided on a base material. The above problems have been solved by providing a thermal transfer recording medium characterized by containing a polyester resin.

The polyester resin used in the present invention has an actual value of 5 (18 to 260, preferably 20 to 120).

The polyester resin used in the present invention has a hydroxyl value of 18
If it is less than y% y .

The polyester resin of the present invention can be produced, for example, by polycondensation of a polyhydric alcohol and a polybasic acid; ring-opening polymerization of a cyclic ester such as a lactone, etc., but it is preferable to combine a glycol component and a dicarboxylic acid component. It is a polyester resin produced by one condensation of

Examples of glycol components include ethylene glycol, 1.2-f propylene glycol, 1.3-butanol, 1.4-butanol, neopentyl glycol, 1,6-hexaneol, diethylene glycol, triethylene glycol, etc. Aliphatic glycol; 1.
Alicyclic glycols such as 4-cyclohexane dimetatool: aromatic glycols such as 4,4'-hydroxyethyl-oxyphenylpro/4-n, among others,
Aliphatic glycols having 2 to 10 carbon atoms are preferred.

Ducarzanic acid components include, for example, aliphatic dicarboxylic acids such as azobic acid, succinic acid, azelaic acid, and cepatic acid; alicyclic dicarboxylic acids such as cyclohexanezocaldic acid; and isophthalic acid and terephthalic acid. Aromatic dicarboxylic acids are mentioned, and aliphatic dicarboxylic acids having 2 to 12 carbon atoms are particularly preferred.

However, from the viewpoint of ease of manufacturing polyester resin and solubility in solvents, 30 mol or more of the acid component is aliphatic dicarboxylic acid, and 30 mol or more of the glycol component is aliphatic glycol. It is preferable.

The polyester resin used in the present invention is produced by combining the dicarboxylic acid component and an excess number of moles of the glycol component with respect to the dicarboxylic acid component in the presence of a catalyst that is optionally added.
By polycondensing at 60°C, products with any hydroxyl value can be produced.

In the present invention, the hydroxyl value of the polyester resin was determined by the acetic anhydride-pyridine method.

Examples of the melting medium used in producing polyester resins include organometallic compounds such as tetraisoglovir titanate, tetrabutoxytitanate, subbutyltinzoacetate, and lithium ethoxide; titanium dioxide, zinc acetate, antimony trioxide, and Inorganic metal compounds such as calcium can be used. The amount used is preferably in the range of 0.001 to 0.51 parts by weight based on 100 parts by weight of the resin produced.

In this way, the hydroxyl value used in the present invention is 18 to 2.
The month of 60? Reester resin can be easily produced.

The thermal transfer recording medium of the present invention comprises the above-mentioned polyester t'
! Other thermofusible resins can be used together with I fat as thermofusible binders, such as rosin resins, terpene resins, coumaron indene resins, ethylene-vinyl acetate copolymers, ethylene, etc. - Acrylic acid ester co-M combination etc. can be used. however,
The use of these other heat-melting resins should be avoided because it causes a decrease in heat-sensitive transferability, and should be avoided in order to obtain a sufficiently clear and high-density transferred image even when transferred to plain paper with a smoothness of less than 100 seconds. For this purpose, it is desirable that the amount of other hot melt resins used is 10% by weight or less of the binder component.

As the coloring material used in the thermal transfer recording medium of the present invention, conventionally known coloring materials such as carpen black, inorganic pigments, organic pigments, or dyes can be used without any particular limitation. titanium, red iron,
Inorganic pigments such as alumina white, zinc sulfide, navy blue, yellow lead, precipitated barium sulfate, ultramarine blue, manganese violet, aluminum powder, etc.; naphthol green, naphthol yellow s, +) sole red, nosazo yellow, chrome phthal yellow, heatcock Organic pigments such as blue lake, rhodamine lake, 7-talocyanine blue, anthrapyrimison yellow, quinacridone red, dioxanone pyolet, isoindolinone yellow; dyes such as nigrosine pace, methyl pyolet, t, and oil-soluble azo used.

Although the composition ratio of the heat-melting binder component and the colorant of the present invention is not limited, it is desirable to use the colorant in a range of 0.61 to 20 parts by weight per 100 parts by weight of the binder component.

Further, the substrate used in the thermal transfer recording medium of the present invention is not particularly limited as long as it is a substrate used in this field, but it is preferable that it has resistance to dampness, high dimensional stability, and high surface smoothness. For example, congancer paper, laminated paper,
Papers such as coated paper; Granutic films such as polyethylene, polypropylene, polystyrene, polyethylene terephthalate, polystyrene, and polyimide; Laminated films such as paper-plasty and plastic films; Metal foils such as aluminum foil, etc. are all suitable. used for. The thickness of the support is preferably 30 μm or less, particularly preferably 3 to 20 μm, in order to obtain good thermal conductivity.

The heat-sensitive transfer recording medium of the present invention is manufactured by adding a binder component containing the polyester resin and a coloring material, and, if necessary, a surfactant, a plasticizer, an antioxidant, an ultraviolet absorber, an extender pigment, etc. This can be done by melt-kneading various additives used in the field, or by dissolving or dispersing them in an appropriate solvent and applying the resulting mixture onto a substrate.

Suitable solvents include, for example, toluene, xylene, ethyl acetate, butyl acetate, acetone, and conventionally known coating methods such as reverse roll coater method, extrusion coater method, gravure coater method, etc. Any known technique such as a coater method and wire per coatability can be employed.

The thickness of the heat-sensitive transfer recording layer on the base material of the heat-sensitive transfer recording medium of the present invention is 20 μm or less, preferably 1 to 10 μm.

Furthermore, in the thermal transfer recording medium of the present invention, the undercoat of the transfer layer f)
The base material and its planting on the back side of the base material are optional.

〔effect〕

By using a polyester resin with a hydroxyl value of 18 to 260, the thermal transfer recording medium of the present invention enables the transfer of clear images onto plain paper with low smoothness. This is thought to be because polyester resins having a hydroxyl value of 18 to 260 have excellent affinity for paper cellulose.

Since the polyester resin used in the present invention has a small molecular weight, it has a higher terminal group value than one with a high molecular weight, and therefore has a large number of hydroxyl groups per unit weight, and these hydroxyl groups constitute the transfer paper. It is thought that it shows affinity with the hydroxyl group in the cellulose molecule.

The thermal transfer recording medium of the present invention exhibits particularly excellent transfer properties when paper is used as the transfer medium, but plastic film,
It is also possible to use metal foil or the like as the object to be transferred.

Furthermore, the medium of the present invention has a lower heat of fusion than conventional media using wax as a binder, so printing can be performed with low energy.

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited thereto unless it exceeds the gist thereof. It should be noted that "To" used below refers to "parts by weight".

〔Example〕

1. Synthesis of polyester resin Synthesis example 1 Anopic acid 14 s parts, 1,4-butanfol 114
A portion was placed in a reaction vessel and heated to 140°C to form a homogeneous solution. 0.04 part of tetraisoglobil titanate (catalyst) was added to this solution while stirring under a nitrogen stream, and the temperature was gradually raised to 220°C after 3 hours.Then, while keeping the temperature at 220°C, polycondensation was carried out. The mixture was allowed to proceed and was taken out after 5 hours.The obtained polyester had a hydroxyl value of 112, an acid value of 0.8, and a number average molecular weight of 1000. This is referred to as PE-1.

Synthesis Example 2 The same procedure as in Example 1 was carried out except that the amount of ethylene glycol charged was changed to 71.5 parts, and the hydroxyl value was 56.1 and the acid value was 0.7.
5. A polyester with a number average molecular weight i2000 was obtained. This will be referred to as PE-2.

Synthesis Example 3 The same procedure as Synthesis 11 was carried out except that anopic acid was 116.8 and isophthalic acid was 33.22, and the hydroxyl value was 110 and the acid fi was
A polyester with lti O, 6 and number average molecular weight j = 1020 was obtained. This will be referred to as PE-3.

■ Manufacturing Example 1 of a thermal transfer recording medium A heat-melting ink having the following composition was uniformly kneaded to a thickness of 6 mm.
It was coated on a μm polyethylene terephthalate film using a wire bar, and dried by heating to 50°C. The thickness of the ink was 4.0 μm.

Composition Caden black 5 parts Polyester resin (PE-1) 20 parts Toluene
Ten copies of the obtained thermal transfer recording medium were printed on plain paper (Beck smoothness: 30
Using a thermal printer (a printer equipped with a thin-film serial thermal head with a heating element density of 8 dots/lTlIn), the energy for a printing time of 1 millisecond is generated with an applied power of 0.5 W per heating element. The density was measured using a courser densitometer and found to be 1.30. Similarly, the prints were made using plain paper with Peck smoothness of 54 seconds, 84 seconds, 122 seconds, and 200 seconds. The concentration of each substance is 1.36.1.39.1
．． It was 42.1.43.

Examples 2 to 3 Ink compositions were carried out in the same manner as in Example 1, except that PE-2 and PE-3 were used as polyester resins instead of PE-1 in the ink composition. The causer density of the obtained image was as follows.

Claims (1)

[Scope of Claims] 1. A heat-sensitive transfer recording medium comprising a heat-sensitive transfer recording layer containing a colorant in a heat-fusible binder on a base material, in which the heat-fusible binder has a hydroxyl value of 18 to 2.
A thermal transfer recording medium characterized by containing a polyester resin of No. 60. 2. Polyester resin is 90 to 90% in the heat-melting binder
The recording medium according to claim 1, which is 100% by weight. 3. The polyester resin is a reaction product of a dicarboxylic acid component and a glycol component, and 1 of the dicarboxylic acid components
3. The recording medium according to claim 1, wherein 00 to 70 mol% is aliphatic dicarboxylic acid. 4. The polyester resin is a reaction product of a dicarboxylic acid component and a glycol component, and 10% of the glycol component is
4. The recording medium according to claim 1, wherein 0 to 70 mol% is aliphatic glycol.