JPS63159088A - Thermal transfer material - Google Patents

Abstract

PURPOSE:To efficiently prevent sticking, by providing a specified sticking- preventive layer on one side of a biaxially stretched polyester film having a specified surface roughness and containing a lamellar silicate, and providing a transfer ink layer on the other side. CONSTITUTION:A biaxially oriented film is produced which has a center line average roughness of 0.1-0.8 mum, has a maximum roughness of 0.8-5mum comprises as a main constituent a polyester containing a lamellar silicate. A sticking-preventive layer comprising a silicon-containing group or fluorine- containing group is provided on one side of the oriented film, and a transfer ink layer is provided on the other side of the film to produce a thermal transfer material. The amount of the lamellar silicate added to the polyester film is preferably at least about 60 wt.% based on the total amount of additive particles. The material comprising the silicon-containing group or fluorine- containing group may be a resin composition having a siloxane linkage or a perfluoroalkyl group.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a thermal transfer material mainly used when obtaining an image using a thermal head, and more specifically, a thermal transfer material having a transfer ink layer that melts or sublimates by heat on one side thereof. The present invention also relates to a thermal transfer material having a stick prevention layer on the other side.

[Prior art] To prevent so-called sticking, which is the fusion between the base sheet and the thermal head, which occurs when printing is performed under high energy due to demands for high speed and multicolor printing when using a thermal head. Various anti-stick layers have been proposed.

For example, a method of providing a metal layer (Japanese Unexamined Patent Publication No. 54-14315
2) A method of providing a layer of silicone or epoxy (JP-A-55-7467), or a method of adding wax to the anti-stick layer (JP-A-6L-143194)
) etc.

[Problems to be Solved by the Invention] However, although these anti-stick layers do not cause stickiness of the head, they have poor slip properties and tend to wrinkle when the film is made into a thin film to achieve high-speed printing, for example. Therefore, a method of adding various inorganic particles to the anti-stick layer has been proposed, but the particles in the coating liquid settle over time and the quality is unstable, and if a large amount is added to impart high-temperature slipperiness. However, there are problems in that the strength of the coating film decreases, or the stain transferability of the head deteriorates due to the shearing of inorganic particles (so-called white powder).

The present invention aims to solve these problems and provide a thermal transfer material with excellent high-speed printing performance.

[Means for Solving the Problems] The present invention mainly uses a polyester having a center line average roughness of 0.1 to 0.8 μm and a maximum roughness of 0.8 to 5 μm and containing a layered silicate. A thermal transfer material is characterized in that a stick prevention layer having a silicon group or a fluorine group is provided on one side of a biaxially oriented film as a component, and a transfer ink layer is provided on the other side.

The polyester in the present invention includes ethylene terephthalate, ethylene α,β-bis(2-chlorophenoxy)ethane-4,4°-dicarboxylate, ethylene α,β-
The main component is at least one structural unit selected from -bis(phenoxy)ethane-4,4-dicarboxylate and ethylene 2,6-naphthalate units. However, within a range that does not impede the present invention, preferably 5 mol%
Other components may be copolymerized as long as they are within the range.

In addition, polyester containing ethylene terephthalate and ethylene α,β-bis(2-chlorophenoxy)ethane-4,4-dicarboxylate as main components has good runnability and operability when formed into a thin film. This is particularly desirable.

Further, other components other than those mentioned above may be copolymerized within a range that does not impede the present invention, preferably within 10 mol%.

The film of the present invention has the above-mentioned composition as its main component, but other polymers may be blended within the range that does not impede the purpose of the present invention, and antioxidants, heat stabilizers, lubricants, and ultraviolet absorbers may be added. , nucleating agents, and other inorganic or organic additives may be added to the extent that they are normally added.

The polyester film used in the present invention is one in which the composition made of the polyester is biaxially oriented, and the F5 value in the longitudinal direction of the film is 10 ki/mm2 or more, preferably 15 k'i/mm2 or more, more preferably 15 k'i/mm2 or more. When is 30 ks/mm2 or more, plastic deformation due to the tension of the transfer machine does not occur, and the film can be wound without losing its shape, which is more preferable. The upper limit is not specified, but it is usually 1
00kq/mm2 or less.

The film of the present invention has a temperature of 290°C, 200 sec -
1 Te melt viscosity is 800 to 10,000 poise, especially 10
When it is in the range of 00 to 7000 poise, handling property is good and it is preferable.

The thickness of the polyester film of the present invention is not particularly limited, but is usually 0.5 to 20 μm, preferably 0.5 to 1
0 μm1, more preferably 0.5 to 7 μm.

The polyester film according to the present invention has a center line average roughness of 0.1 to 0.8 μm, preferably 0.12 to 0.4 μm.
0 μm1, more preferably 0.15 to 0.28 μm, and the maximum roughness is 0.8 to 5 μm1, preferably 1
．． 0 to 3.2 μm, more preferably 1.2 to 2.0 μm
belongs to.

If the center line average roughness and maximum roughness are smaller than this range, the stick resistance is not sufficient and it is not preferred. On the other hand, if it is larger than this range, contact with the thermal head will not be sufficient and transferability will deteriorate, which is not preferable.

In particular, it is preferable that only one side of the film is within the scope of the present invention and the round side (transfer ink side) is a smooth film, because the transfer rate is further improved.

In the present invention, it is necessary to use layered silicates as inorganic particles added to obtain a rough surface as in the present invention. The ratio (weight ratio) of the layered silicate to the total added particles is not particularly limited, but is usually 30% by weight or more, preferably 60% by weight or more, more preferably 85% by weight or more and 100% by weight or less. It is.

By using a layered silicate in this way, the transferability of the transfer ink is improved, which is preferable. The reason for this is not clear, but the layered silicate described in the present invention usually has an aspect ratio of 20 or more, and in more extreme cases, 200 or more and 5,000 or less, which is significantly different from normal particles in terms of adjacency. It is thought that the transferability is improved in this way.

The general formula of the layered silicate mentioned here is as follows.

Xo, 3-1. IY 1.8-3.2 3.5-4.
5010>(Z Wl, 8-2.2 X: (interlayer position) cation with coordination number 12 -Li",
Na”, Ni+, Rb”, Ca”, Sr2”
.

Ba2・Y: (octahedral position) cation with coordination number 6 -Li",
Hg2”, Fe””, Ni2”, Hn2+, A
13”.

Fe"Z: (tetrahedral position) cation with coordination number 4 -3i", G
e”, (part of Si4+ is replaced with Al3”, Fe”C3
+> Wnie OH or “ Typical layered silicates include the following.

(Non-hydratable mica) Fluorine phlogopite [niH(13(Al5i3010)W2
] Potassium tetrasilicon mica [KH+; + 2.5 (Sia
010)W2] Duolite [KM(121i(Si)
4 010) W2co (hydration swellable mica) Na-tetrasilicon mica [NaHg2.5 (3140to
) Machiko Na-teniolite [Na14! :12 Ll
(Si4010) W2 co[i-Duolyr~[Lu+
a2 ta(si40io)W2] Na or Li hectorite [(Na, Ll) 1/3 H! J22/3
[11/3 (S14 010)'2] """ Montmorillonite type, where W is -F or -011 Among these, hydration-swellable fluorinated mica is particularly preferred.

Here, swelling property refers to the so-called "swelling" caused by coordinating water between layers.
An inorganic layered silicate that has the properties of

Swellable mica suitable for the present invention is structurally a phyllosilicate in which the ratio of Si to 0 of Si04 tetrahedron is theoretically 2:5, and has a crystal structure in which the crystal unit cell is repeated in the thickness direction. A typical example can be expressed as a chemical formula as follows.

X O, 3~1.1Y1.8~3.2 (S' 3.
5-4.5010) Wl. 8-2.2 × = interlayer ion, one or more cationic ions, Y: ion at octahedral position, must be Hg2+ or Mg2+
A part of Li”, Fe””, Ni””, )In
2+, At3", and "C3+" ion substituted with at least one ion selected from the group consisting of O: oxygen W: one or two ions selected from F- or 0■-.

In the present invention, S14+ at the above-mentioned tetrahedral position may be replaced with Ge" or a portion thereof may be replaced with At3", Fe3+, B3+, etc., and the mica referred to in the present invention also includes these.

Specific examples of these include inorganic particles such as natural products such as montmorillonite and vermiculite, and synthetic products such as tetrasilicic mica, duolite, and hectorite, which are synthesized by melting or hydrothermally and having the above general formula.

Among these, synthetic materials are particularly preferred because they have few impurities and have a uniform composition, resulting in uniform crystals.Among these, synthetic materials are particularly preferred because they have excellent crystal flatness, large crystal size, and high aspect ratio. From, IA/y-77,1~Xro,l @L! 12J! -K
xs, x-KL1K (Stys~+o 0Ier)FH
,tr,.

or 'NY-a, I p-)l+o,l MffZt-X5
-1.2-XL TX (S i ?, thAo Q
+o to OH)+-t-z.

(However, X=O, S~1.2) is preferable.

There are various methods for preparing the swellable mica, which is thin in thickness and has a large aspect ratio, which is suitable for the present invention, such as mechanical folding. It is more preferable to chemically form the pleats as shown in the figure, since the aspect ratio is particularly large.

The anti-stick layer used in the present invention has a silicon group or a fluorine group and is not particularly limited, but representative examples include a resin composition having a siloxane bond and a resin having a perfluoroalkyl group. Compositions may be mentioned.

More specifically, what is preferred is a resin composition in which silicone oil or fluorine oil is added in an amount of O01 to 10% by weight, preferably 1.0 to 5.0% by weight. I can do it.

Among them, it is preferable to use a thermosetting resin as the resin composition.

Typical examples of silicone oils include polymers or copolymers of dimethylsiloxane, methylphenylsiloxane, and methylhydrogensiloxane, or epoxy-modified, alkyl-modified, amine-modified, carboxyl-modified, and alcohol-modified products of these polymers. products, fluorine modified products, alkyl aralkyl polyether modified products,
Examples include modified epoxy polyethers and modified polyethers.

Typical examples of fluorine oil include: F etc. can be mentioned.

Other examples of those having a siloxane bond include silane coupling agents.

Typical examples of the silane coupling agents mentioned here include terminal amino groups, vinyl groups, and epoxy groups.

Chlor group, methyl group, phenyl group, mercapto group.

Examples include those having a per70-roalkyl group. Among these, it is preferable to use a combination of those having a 7-mino group and those having an epoxy group at the terminal. It is more preferable to further add to these a silane coupling agent having a methyl group or a per-70-roalkyl group at the end. When the silane coupling agent in the present invention is a dimethoxy type, more preferably a trimethoxy type,
It is suitable from the standpoint of state king resistance. Although it is not necessary to use a curing agent, typical curing agents include organic carboxylic acids, nitrous acid, nitrous (iiIt!), alkali metal salts of aluminic acid, carbonic acid, and thiocyanic acid, octylic acid, and naphthenic acid. each metal salt.

Organic amine salts, organic tin compounds, boron fluoride complex, zinc borofluoride, tin borofluoride, tetramethylaluminum hydroxide, tetra-n-butylphosphonium hydroxide, quaternary ammonium hydroxide, quaternary phosphonium and hydroxide, aluminum chelate Compounds, various epoxy curing agents, etc. It is also possible to use a mixture of two or more of these.

In particular, aluminum compounds having the following structure are extremely effective in achieving the objects of the present invention. The compound has the general formula % formula %) (where Y is OL (L is alkyl of C), 1 to 6 z is -a formula M'COCH2COM'' or M3C
At least one ligand selected from 1 to 6 derived from the compound represented by OCH2COOM4 (M', M2.M3.M' are all C alkyl), m is an integer of 0 to 3 ). Specific examples of this compound include various compounds, but preferred from the viewpoint of solubility in the composition, stability, effect as a curing catalyst, etc. are aluminum 1so-propoxide, aluminum ethoxide, aluminum tert −
Butoxide, aluminum acetylacetonate, aluminum bis-ethylacetoacetate mono-acetylacetonate, aluminum di-n-butoxide
Monoethyl acetoacetate, aluminized G-1S
O-propoxide-mono-methylacetoacetate, luaminiram-di-8eC-butoxide-mono-ethylacetoacetate, aluminum di-methoxide-mono-methylacetoacetate, and the like. It is also possible to use a mixture of two or more of these.

The curing agent is added in an amount of 0.0% per 1 part by weight of the silicon compound.
0001 to 0.5 parts by weight, particularly preferably 0.0005
~0.2 parts ffi is suitable; less than this will result in insufficient curing, while more than this will cause defects such as decreased transparency and water resistance of the coating film or resin.

In addition, other materials having fluorine groups include resin compositions, preferably thermosetting resin compositions, containing polymers having per-70-roalkyl groups such as polytetrafluoroethylene or polyvinidene fluoride in the form of fine particles. Examples include those in which a polymer having a 70-roalkyl group is applied in an emulsion state, and a film is formed by heating and drying.

However, among these, a stick prevention layer containing a silicone oil, a silane coupling agent having an amino group, and a silane coupling agent having an epoxy group as main components is particularly suitable from the viewpoint of stick resistance.

As the transfer ink layer in the present invention, a conventionally known heat-sensitive transfer ink layer is used, such as a heat-melt wax layer in which pigments or dyes are dispersed, or a heat-sensitive sublimation transfer layer in which a sublimation dye is added to a binder. be able to.

As the binder in the hot-melt wax layer, carnauba wax, paraffin wax, acid wax, or a suitable synthetic binder is used, and as the coloring material, dyes or pigments are used.
It is added in an amount equivalent to 30% parts by weight.

The heat-sensitive sublimation transfer layer is composed of a sublimable dye contained in a binder resin, and has a thickness of about 0.2 to 5.0 μm. The dye in this heat-sensitive sublimation transfer layer is preferably a disperse dye, and this dye preferably has a molecular weight of about 150 to 400. The dye is selected in consideration of thermal sublimation temperature, hue, weather resistance, stability in the binder resin, etc., and specific examples include the following.

Mikenton Poyester Yello
w-YL (Mitsui Toatsu, C, 1, Dispers Y
yellow-42), Kayaset Tello
w-G (manufactured by Nippon Kabu, C, 1, Dispers Yel
low77), PTY-52 (manufactured by Mitsubishi Kasei, C,1
, 5olvent Yellow14-1) , Hi
keton Po1yester Red BSR (manufactured by Mitsui Toatsu, C, I-, [)isperSe Red? ?
? ? ? ), t<ayaset Red B (
Made by Nippon Kabu, C, 1, Disperse Red B)
, PTB-54 (manufactured by Mitsubishi Kasei, C01, Dispe
rse Red50), Hiketon Po1y
ester Blue FB [) (Mitsui Toatsu, C,
1, Disperse Blue 68), PTB
-67 (manufactured by Mitsubishi Kasei, C, I, [)isperse B
241).

Kayaset Blue 906 (manufactured by Nippon Kabu, C
, I, 5olvent 112), etc.

Depending on the sublimation temperature of the dye and the magnitude of the covering power in the developed state, the dye is about 5-70% in the heat-sensitive sublimation transfer layer.
The content is preferably about 10 to 60% by weight. Further, as the binder resin, one is usually selected that has high heat resistance and does not hinder the transfer of dye when heated, and for example, the following are used.

■ Cellulose resins ethylcellulose, hydroxyethylcellulose, ethylhydroxycellulose, hydroxypropylcellulose, methylcellulose, cellulose acetate, cellulose acetate, etc.

■ Vinyl resins Polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinylpyrrolidone, polyester, polyacrylamide, etc.

Next, a method for manufacturing a thermal transfer sheet of the present invention will be explained.

First, the method of incorporating a layered silicate having a predetermined average particle size can be carried out by any known method, but the most effective method is to mix and disperse the layered silicate in the diol component of polyester in the form of a slurry.

After thoroughly drying the polyester pellets, the polyester pellets are fed to a known melt extrusion source and melt-extruded into a sheet through a slit-shaped die at a temperature above the melting temperature of the pellets and below the temperature at which the polymer decomposes, and then cooled and solidified. to make an unstretched sheet.

Next, this unstretched film is biaxially stretched and oriented. As the stretching method, a sequential biaxial stretching method or a simultaneous biaxial stretching method can be used, but a sequential biaxial stretching method is particularly preferred. In this case, the stretching conditions include longitudinal direction,
A method of stretching 3.0 to 4.0 times in the longitudinal direction at a temperature in the range of above the glass transition point of the polymer and below the cold crystallization temperature in both width directions, and then stretching 3.2 to 4.5 times in the width direction. It's suitable. The stretching speed is preferably in the range of 103 to 107%/min. Further, the method of further stretching the stretched film in at least one direction is effective in making the film even more wrinkle-free during use.

Next, the stretched film is heat treated, and the heat treatment conditions in this case include a temperature of 180°C to 230°C, preferably 19°C.
A method of heat treatment for 0.5 to 60 seconds in the range of 0°C to 220°C is effective in making the film even more wrinkle-free. Furthermore, it is effective to perform the heat treatment under a fixed length condition to further reduce wrinkles.

The film thus obtained may be subjected to corona discharge treatment in air or other various atmospheres, if necessary. Anchor treatment may also be performed using a known anchor treatment agent such as urethane resin or epoxy resin, but this is usually not necessary. After coating the film with a heat-resistant protective layer using a known method such as gravure coating, reverse coating, or spray coating,
Dry at 50°C for about 1 sec to 15 minutes. In this case, the solvent is not particularly limited, but usually water, alcohol, or a mixture of water and alcohol is used. Subsequently, heat-melting or sublimation ink is coated on the opposite side in the same manner, and then dried at a predetermined temperature. These coats may be performed in any order, and of course may be performed simultaneously.

Alternatively, a coating layer may be formed separately and laminated from scratch, but since the layer is somewhat insufficient in strength, it is preferable to coat it directly onto the base film.

The transfer ink layer can be coated by a known method such as barcode coating, reverse coating, gravure coating, etc., regardless of whether or not the heat-resistant protective layer is coated.

Moreover, when the base film is biaxially stretched, it is possible to apply it during the manufacturing process. Specifically, to give one example, a heat-resistant protective layer is applied to at least one side of a polyester film after being stretched in one direction, and after drying or while being dried, it is stretched in a right angle direction and then subjected to heat treatment. After stretching in this direction, it may be re-stretched in the one direction and heat treated.

[Effects of the Invention] The present invention provides a stick prevention layer having a silicon or fluorine group on the surface of a polyester film containing a layered silicate whose average roughness and maximum roughness are within a specific range.
The result is a film that does not cause sticking without impairing transferability.

Since the thermal transfer material of the present invention has excellent stick resistance and transfer properties, it is particularly suitable for use in facsimiles, barcode printers, graphic printers, image processing printers, and automatic ticket issuing machines.

[Method for measuring physical properties, evaluation criteria] The measuring methods and evaluation criteria for physical properties in the present invention are as follows.

■Surface roughness and maximum roughness (μm): Indicates the measured value using a stylus type surface roughness meter (cutoff o, oamm, measured value 4 m++tr (7) value. However, JIS-8-06
01).

■ Stick phenomenon: When recording was performed using clay coated paper as the recording paper under the following thermal head recording conditions, the case where the stick phenomenon occurred was evaluated as "x", and the other cases were evaluated as "0".

Linear density of main and sub-scanning = 4 dots / 0.
9W/dot head heating time: 5ms ■ Transferability: When recording with clay coated paper as the recording paper under the following thermal head recording conditions, the one with good transfer condition was rated as "
0", those with poor print quality due to blur, insufficient transfer, etc.
I made it J.

Linear density of main and sub-scanning: 4 dots/mm Recording voltage 0
．． 6W/dot head heating time: 5ms [Example] Next, embodiments of the present invention will be described based on Examples.

Examples 1 to 4, Comparative Examples 1 to 2 A predetermined amount (shown in the table) of calcium carbonate (average by precipitation method) was added to polyethylene terephthalate with an intrinsic viscosity of 0.61 measured by melting O-chlorophenol at 35°C. particle size 0.8 μm) or fluorine phlogopite/KHg3 (
A raw material containing Al5i3010) F2 (average particle size 0.8 μm by sedimentation method) is prepared. The raw material thus obtained is melted using an extruder, extruded from a die, and rapidly cooled and solidified on a drum. After longitudinally stretching the sheet thus obtained at 95°C and 3 times the length, 11
Transverse stretching is carried out 3.2 times at 0°C, followed by 5% relaxation heat treatment at 225°C.

After corona discharge treatment was applied to one side of the film thus prepared, 100 parts by weight of carnauba wax, 30 parts by weight of microcrystalline wax, 15 parts by weight of vinyl acetate-ethylene copolymer, and 2 parts by weight of carbon black were added.
5 μm of heat-melting ink consisting of a 0-weight portion is applied. On the opposite side, apply a heat-resistant protective layer with the following composition to a dry thickness of 0.
．． Apply 2 μm. However, drying was performed in hot air at 150°C for 2 minutes.

[Heat-resistant protective layer composition] Mizozo Composition ratio However, lithium chloride was used as a hardening agent.

As seen in the table, it can be seen that within the range of the present invention, the stick phenomenon and transferability are good.

Example 5 A film was formed and evaluated in the same manner using a 7:3 mixture of fluorophlogopite and calcium carbonate as the inorganic particles to be added. However, the average particle size determined by the sedimentation method was 0.6 μm.

As shown in the table, the film had similar excellent transferability and stick resistance. However, although not shown in the table, the transferability was slightly inferior to that of Example 3.

Claims (1)

[Claims] Center line average roughness 0.1-0.8μm, maximum roughness 0.8
~5 μm, and a stick prevention layer having a silicon group or a fluorine group is provided on one side of a biaxially oriented film mainly composed of polyester containing layered silicate, and a transfer ink layer is provided on the other side. A thermal transfer material characterized by: