JP2990695B2 - Transfer material for printer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a transfer material for a printer. More specifically, the present invention relates to an ink transfer material excellent in dimensional stability, durability, unevenness in thickness, running properties, and printing characteristics used for a typewriter and a thermal printer.

[Problems to be solved by conventional technology and invention]

As a base material of a transfer material for a printer, a polyester film is used because it has excellent properties such as high crystallinity, high melting point, heat resistance, chemical resistance, strength, and elastic modulus.

For dot impact type transfer materials for typewriters and printers, it is necessary to withstand the tension and printing pressure applied to the transfer ribbon and to have durability that can be used repeatedly.
In addition, since a transfer film of a thermal transfer method uses an extremely thin base film, it is required to have high strength and high dimensional stability.

However, in a transfer material using a normal biaxially oriented polyester film as a base film, elongation of the film at the time of transfer and plastic strain in the remaining portion of the print easily occur, which is satisfactory for a transfer ribbon having a high tension or printing pressure. It was not a thing.

On the other hand, as the base film, although high strength film is desired, for example, when the F ₅ value in the longitudinal direction using a high normal strong polyester film, longitudinal split tends to occur at the time of transfer, also sensitive In the case of thermal transfer, there is a drawback that the thermal shrinkage is too large, so that it cannot be used for transfer.

[Means for solving the problem]

In view of the above problems, the present inventors have conducted intensive studies,
The inventors have found that a transfer material provided with a transfer ink layer on one side of a polyester film satisfying certain physical properties has excellent characteristics, and arrived at the present invention.

That is, the gist of the present invention resides in a transfer material for a printer in which a transfer ink layer is provided on one surface of a biaxially stretched polyester film that satisfies the following formulas at the same time.

▲ S ¹⁰⁰ ₃₀ ▼ ≦ 2.35-0.1 ・ F ₅ … | F ₅ −F ₅ ′ | ≦ 1.5… 13 ≦ F ₅ ≦ 15 (where ▲ S ¹⁰⁰ ₃₀ ▼ represents the heat shrinkage (%) of the film after treatment at 100 ° C. for 30 minutes. F ₅ indicates the strength at 5% elongation (kg / mm ² ) of the film in the longitudinal direction, F ₅ ′ indicates the strength at 5% elongation of the film (kg / mm ² ), and n _MD indicates the strength of the film. Hereinafter, the present invention will be described in detail.

The polyester referred to in the present invention is terephthalic acid, isophthalic acid, aromatic dicarboxylic acids such as naphthalene-2,6-dicarboxylic acid or esters thereof, and ethylene glycol, diethylene glycol, tetramethylene glycol, neopentyl glycol, etc. It is a polymer obtainable by polycondensation with glycol. Such a polyester can be obtained by directly polycondensing an aromatic dicarboxylic acid and glycol, or by subjecting an aromatic dicarboxylic acid dialkyl ester and glycol to a transesterification reaction, followed by polycondensation, or a method of preparing an aromatic dicarboxylic acid by dicondensation. It can be obtained by a method of polycondensing a glycol ester.

4. Representative examples of such polymers include polyethylene terephthalate and polyethylene-2,6-naphthalenedicarboxylate.

The polyester of the present invention may be a homopolymer, and a range that does not deteriorate its properties, for example, 15 mol% or less of the dicarboxylic acid component is 15 mol% of the dicarboxylic acid component or diol component other than the aromatic dicarboxylic acid whose main component is not more than 15 mol%.
A copolymer polyester in which the following is a diol component other than the main component diol may be used.

Further, a polymer blend of the polyester and another polymer may be used. Other polymers that can be blended include polyamides, polyolefins, polycarbonates, other polyesters, and the like. Further, fine particles may be added in order to impart lubricity to the polyester film. Such fine particles include inert external particles such as kaolin, clay, calcium carbonate, silicon oxide, calcium terephthalate, aluminum oxide, spherical silica, and titanium oxide, high melting point organic compounds insoluble in melt film formation of polyester resin, and crosslinked polymers. And an internal particle formed inside the polymer during the production of the polyester by a metal compound catalyst such as an alkali metal compound or an alkaline earth metal compound used in the synthesis of the polyester. Of course, each particle may be used alone or in combination. The amount of fine particles contained in the film is usually 0.
The range is from 01 to 5% by weight, preferably from 0.05 to 3% by weight, and the average particle size of the particles is usually from 0.1 to 10 μm, preferably from
It is in the range of 0.3 to 3 μm.

Further, the polyester in the present invention may contain additives such as a stabilizer, a colorant, an antioxidant, and an antifoaming agent, if necessary.

The film of the present invention can be obtained by using the polyester described in detail above.
% Elongation strength at F ₅ value and 100 ° C., the thermal shrinkage rate after 30 minutes ▲
S ¹⁰⁰ ₃₀ ▼ must satisfy the following expression.

▲ S ¹⁰⁰ ₃₀ ▼ ≦ 2.35-0.1 · F ₅ … Films that do not satisfy the above formula have poor dimensional stability,
Does not stand use. Usually, ▲ S ¹⁰⁰ ₃₀ ▼ is 1.0% or less, preferably 0.7% or less, more preferably 0.5% or less. Films with ▲ S ¹⁰⁰ ₃₀ ▼ exceeding 1% shrink when processed into a transfer material and are unsuitable. The F ₅ value is preferably, 13~15kg / mm ^2, more preferably 13.5~14.5kg
/ mm ² range. If the F ₅ value is less than 13 kg / mm ² , it is difficult to make the film thinner, and a film having an F ₅ value exceeding 15 kg / mm ² is not preferable because of poor dimensional stability. Incidentally, the difference between the elongation of 5% strength F ₅ 'value of the lateral direction and F ₅ value of the film 1.5 kg /
mm ^{2 or} less, more preferably 1.0 kg / mm ^{2 or} less.

Films with a difference of more than 2.0 kg / mm ² are not preferred because they tend to tear in the vertical or horizontal direction, especially when used as a dot impact transfer material.

Further, the film of the present invention has a strength F ₅ at 5% elongation in the machine direction,
It is necessary that the longitudinal refractive index n _MD and the average refractive index satisfy the following formula.

Films that do not satisfy this formula are not preferred because of poor productivity and increased cost.

The average refractive index of the film of the present invention is usually 1.60
It is in the range of 2 to 1.605. Films having a molecular weight of less than 1.602 are inferior in dimensional stability, and films having a molecular weight of more than 1.605 are not practical because the film breaks during printing.

The film thickness of the present invention is usually in the range of 1.0 to 9.0 μm, preferably 1.0 to 6.0 μm, and more preferably 1.0 to 4.0 μm. If the film thickness is less than 1.0 μm, the film strength is low, so that the film is easily stretched and cannot be used as a transfer material. On the other hand, a film exceeding 9.0 μm is not suitable as a transfer material for a printer. The thickness unevenness R ⁵ in the longitudinal direction 5m of the film of the present invention is usually less than 5%, preferably 3% or less. In R ⁵ is 5% or more, the running of the film is deteriorated, and printing properties when formed into a transfer material to deteriorate.

Next, the method for producing a polyester film of the present invention will be described in more detail.

Polyester chips containing fine particles such as kaolin, silica, calcium carbonate, and aluminum oxide and additives such as stabilizers, coloring agents, defoamers, organic lubricants, and polyalkylene glycols are dried by a conventional method. Extruded through an extruder and cooled and solidified on a rotating cooling drum to form an undrawn polyester sheet. At this time, it is preferable to use a conventional electrostatic application cooling method. The substantially amorphous film thus obtained is stretched at a draw ratio (λ _t ).
The film is stretched in the longitudinal direction within the range of 4.0 to 9.0, and then stretched in the transverse direction at a stretch ratio of 3.2 times or more to form a biaxially oriented film.

In producing the film of the present invention, the stretching in the longitudinal direction is as follows: (A) the amorphous film is stretched 1.2 to 4.0 times and the birefringence is 1 × 10 ^{−3 to} 2.5 × 10 ^−2. (B) The birefringence is 3.0 to 10 ^{-2 to} 8.0 at a draw ratio of 1.1 to 3.5 times without cooling the film temperature below the glass transition point.
× longitudinally stretched in one stage or multiple stages such that 10 ^-2, (C) after the film temperature was cooled to below the glass transition point, in a single stage or multi-stage by heating the (D) film above the glass transition temperature It preferably comprises a step of longitudinal stretching.

Further, the biaxially oriented film after the transverse stretching may be subjected to longitudinal and / or transverse stretching again if necessary. In particular, it is preferable to heat-set after re-horizontal stretching before heat-setting. The heat setting temperature at that time is at least 200 ° C. or more, preferably 210 ° C. or more.

Next, a transfer ink layer is formed on the biaxially oriented polyester film of the present invention obtained as described above. At this time, the film may be subjected to a pretreatment such as a corona discharge treatment or an undercoat if necessary.

The transfer ink of the present invention is not particularly limited, and a known ink can be used. Specifically, it is possible to use a binder component, a coloring component, or the like as a main component and a softener, a flexible agent, a melting point regulator, a leveling agent, a dispersant, or the like mixed as an additive component as necessary. it can.

As specific examples of the main component, well-known waxes such as paraffin wax, carnauba wax, and ester wax as binder components, and various low-melting polymer chains are useful. Organic or inorganic pigments or dyes are useful. Inks include sublimable inks.

As a method for providing the transfer ink layer on one side of the film of the present invention, known methods, for example, hot melt coating, gravure with a solvent added, reverse, using a solution coating method such as a slit die method and the like it can.

When the transfer material is used as a thermal transfer material,
In order to prevent sticking of the thermal head portion, it is desirable to provide a known anti-fusing layer on the side of the film where the transfer ink layer is not provided.

〔Example〕

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to the following Examples as long as the gist of the present invention is not exceeded.

The method for evaluating the characteristics of the film and the tape is as follows.

(1) F ₅ value Co. INTESCO Ltd., tensile tester in Tesco model 20
Using a type 01, cut in the vertical direction of the film in a room adjusted to a temperature of 23 ° C and a humidity of 50% RH, length 50mm, width 15
The sample film of mm pulled at a rate of 50 mm / min in the longitudinal direction, the strength at 5% elongation was F ₅ value.

(2) Heat shrinkage ▲ S ¹⁰⁰ ₃₀ ▼ (%) The heat shrinkage was carried out in a 100 ° C. atmosphere for 30 minutes in an untensioned state, and the length of the sample before and after the heat treatment was calculated by the following equation.

(3) Thickness unevenness R ⁵ (%) by Anritsu Electric Co., Ltd. continuous film thickness meter (Electronic micrometer used), measured along the longitudinal direction of the biaxially oriented film, (5 m for the length) the formula It was calculated from:

(4) using n _MD Atago Optical Co. Abbe refractometer to measure the refractive index of the film vertical direction with respect to the sodium D line at 23 ° C..

(5) Average refractive index, degree of plane orientation ΔP Using an Abbe refractometer manufactured by Atago Optical Co., Ltd., the maximum value nγ of the refractive index in the film plane and the refractive index n in a direction perpendicular to the maximum value nγ
β and the refractive index nα in the thickness direction of the film were measured, and the average refractive index and the degree of plane orientation were calculated from the following equations. The measurement of the refractive index was performed at 23 degrees using a sodium D line.

(6) Characteristic evaluation as thermal transfer material One side of the polyester film has 35 parts by weight of paraffin wax, 30 parts by weight of carnauba wax, 15 parts by weight of low molecular weight polyethylene, and 12 parts by weight of carbon black. The layer was applied to a dry film thickness of 2 μm. On the other side of the color material layer, a silicone-based heat-resistant protective layer having a thickness of 0.5 μm was provided. The film was run and printed using a facsimile telecopier type 245 manufactured by Fuji Xerox Co., Ltd., and the runnability and printability were evaluated according to the following ranks.

Example 1 Polyethylene terephthalate chip (intrinsic viscosity 0.60,
0.3% by weight of Al ₂ O _{3 having} an average particle diameter of 0.02 μm and an average particle diameter of 0.7 μm
0.3% by weight of calcium carbonate added during polymerization)
Was dried at 180 ° C. for 5 hours, extruded at 285 ° C. in a sheet form from a T-die, and cooled and solidified on a rotating drum maintained at 45 ° C. to obtain an unstretched amorphous film having a width of 350 mm. At that time, a known electrostatic adhesion method was used. First, the obtained amorphous film is vertically moved to the first position by utilizing the peripheral speed difference between the multi-stage nip rolls.
The film was stretched 1.6 times at a film temperature of 112 ° C. as a step, and then continuously stretched 2.8 times at a film temperature of 113 ° C. as a second step in the longitudinal direction.

The birefringence of the film after the first stretching is 3.0.
× 10 ^-3 , and the birefringence of the film after the second-stage stretching was 3.8 × 10 ^-2 . The film thus obtained is
After the film was once cooled to 40 ° C., it was further heated to a film temperature of 75 ° C., and the third stage of longitudinal stretching was performed at 1.3 times. The birefringence of the obtained longitudinally stretched film was 0.078.

Next, stretch 3.9 times in the transverse direction at 110 ° C in a tenter.
Tension heat setting was performed at 225 ° C. to obtain a film having a thickness of 4.8 μm.

One side of the obtained film was coated with a fluorine-based polymer as a sticking prevention layer, and the other side was coated with a wax transfer ink layer to obtain a transfer material.

Comparative Example 1 A film having a thickness of 5.4 μm was obtained in the same manner as in Example except that the third-stage longitudinal stretching ratio was changed to 1.01. The birefringence after the third stage of longitudinal stretching was 0.052. The same coating as in Example 1 was performed on the obtained film to obtain a transfer material.

Comparative Example 2 A film having a thickness of 3.8 μm was obtained in the same manner as in Example 1, except that the third-stage longitudinal stretching temperature was 83 ° C. and the stretching ratio was 1.3 times. The same coating as in Example 1 was performed on the obtained film to obtain a transfer material.

Comparative Example 3 A film having a thickness of 3.8 μm was obtained in the same manner as in Example 2 except that the heat setting temperature was changed to 195 ° C. The same coating as in Example 1 was performed on the obtained film to obtain a transfer material.

 The results obtained above are summarized in Table 1.

[Effect of the Invention] The transfer material for a printer of the present invention has excellent dimensional stability,
It has durability, uneven thickness, running properties, and printing characteristics, and has high industrial value.

Continuation of the front page (72) Inventor Takatoshi Miki 5-8, Mitsuya-cho, Nagahama-shi, Shiga Prefecture Inside the product research center of Diafoil Co., Ltd. (56) References JP-A-62-85984 (JP, A) JP-A-60-1985 104393 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) B41M 5/38-5/40

Claims (1)

(57) [Claims] 1. A transfer material for a printer comprising a biaxially stretched polyester film, which satisfies the following formulas (1) and (2), provided with a transfer ink layer on one surface. ▲ S ¹⁰⁰ ₃₀ ▼ ≦ 2.35-0.1 ・ F ₅ … | F ₅ −F ₅ ′ | ≦ 1.5… 13 ≦ F ₅ ≦ 15 (where ▲ S ¹⁰⁰ ₃₀ ▼ represents the heat shrinkage (%) of the film after treatment at 100 ° C. for 30 minutes. F ₅ indicates the strength at 5% elongation (kg / mm ² ) of the film in the longitudinal direction, F ₅ ′ indicates the strength at 5% elongation of the film (kg / mm ² ), and n _MD indicates the strength of the film. It indicates the refractive index in the longitudinal direction, and indicates the average refractive index of the film.)