JPH028090A - Thermal transfer polyester film - Google Patents

Abstract

PURPOSE:To obtain excellent travelling property, sticking resistance, printing property, slitting property, and transferring property of ink by a method wherein thermoplastic resins other than polyester are contained at a specific rate. CONSTITUTION:Thermoplastic resin of different kind from polyester is fused or softened at 300 deg.C and reveals a sea island structure by mixing to be stirred with polyester. The resin to which surface roughness is given when the resin is made into a film by mixing without thoroughly being compatible with polyester, is used. A mixing amount of a thermoplastic resin of a different kind to the polyester is 0.02wt.% or over to and excluding 3wt.%. When the mixing amount is under 0.02wt.%, the obtained surface roughness of the film is not enough, and working properties such as winding out, coiling, travelling property, etc. of the film are not satisfied. Further, the thermal transfer material coated by transfer ink i.e. a ribbon comes to crease very easily. Furthermore, sticking to a thermal head comes to occur easily. Besides, when the mixing amount is 3wt.% or over, the obtained surface of the film is excessively roughened and the printing property is deteriorated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a thermal transfer recording film,
More specifically, the present invention relates to a film that has excellent running properties and staking resistance, excellent slitting properties, and good flatness, and is suitable for high-speed printing.

[Problems to be solved by conventional technology and invention]

Although various recording methods have been known in the past, thermal transfer using a thermal recording device such as a thermal printer is widely used because of its excellent operability and maintainability. As a base film for this printer transfer material, a polyester film, especially a co-axially oriented film of polyethylene terephthalate, has been used because it is excellent in terms of high melting point, heat resistance, chemical resistance, mechanical strength, etc. It is also well known that inorganic particles such as silicon dioxide or titanium dioxide, which are inert to polyester and have an appropriate particle size, are blended into the film in order to improve its runnability and statesking resistance.

However, in recent years, with high-speed transfer, there is a tendency to increase the surface roughness of the base film in order to maintain a high level of running performance, but according to the present inventor's knowledge, new problems arise in this case. .

That is, in order to develop such surface roughness, it is necessary to increase the particle size and grain size of the inorganic particles contained in the film, but as a result, the slitting properties of the film become poor.

In other words, heat-sensitive transfer agents are used as strips by applying an ink layer to one side of a polyester film and, if necessary, providing a heat-resistant protective layer to the opposite side. The slitting blade is easily damaged due to the inorganic particles added to the film to improve the quality.
The edges of the film often bulge.

As a result, the ink layer applied to the film is easily transferred to the opposite surface (running surface), which causes problems such as staining the guide bins and thermal heads of the running system.

[Means for solving problems]

As a result of intensive studies in view of the above-mentioned problems, the present inventor found that a film containing a thermoplastic resin other than polyester is useful as a film for thermal transfer, and has completed the present invention.

That is, the gist of the present invention resides in a polyester film for thermal transfer, characterized in that it contains 0.0.2% by weight or more and less than 3% by weight of a thermoplastic resin other than polyester.

The present invention will be explained in more detail below.

The greatest feature of the present invention is that a mixture of polyester and other thermoplastic resins is used as a film forming raw material.

Examples of the former polyester include terephthalic acid,
A polyester obtained using an aromatic dicarboxylic acid such as naphthalene dicarboxylic acid or an ester thereof and ethylene glycol as main starting materials is used, but it is also possible to use a so-called copolymerized polyester. In this case, the dicarboxylic acid component is one or two oxycarboxylic acids such as terephthalic acid, phthalic acid, isophthalic acid, 6-naphthalene dicarboxylic acid and its isomers, adipic acid, sebacic acid, and p-oxyethoxybenzoic acid. More than one species can be used. Glycol components include diethylene glycol, propylene glycol, butanediol, tI-cyclohexane dimetatool,
One or more types of neopentyl glycol can be used. In any case, the polyester of the present invention refers to a polyester in which gθ mol % or more of repeating structural units have ethylene terephthalate units or ethylene-26-naphthalene units.

On the other hand, in the present invention, polyester and different thermoplastic resins are molded at a temperature of 300°C, which is a typical polyester molding temperature.
Refers to resins that melt or soften at ℃ and develop a so-called seabird structure when mixed and stirred with polyester, specifically polyethylene, polypropylene, polystyrene, poly-p-xylene, polyvinyl acetate, polyacrylate, polymethacrylate 1 , polyvinyl chloride, polyvinylidene chloride, fluorine-based polymer to polyacrylonitrile, polyether, polycarbonate, polybutylene terephthalate, polyamide, polyphenylene oxide, polysulfone, polyphenylene sulfide, ionomer resin, acrylonitrile-styrene resin, acrylonitrile-butadiene-styrene resin, Examples include phenoxy resin.

In any case, in the present invention, any material can be used without any restriction as long as it is not completely compatible with polyester and provides surface roughness when mixed with polyester and formed into a film. One or more thermoplastic resins can be used as needed.

The polyester film in the present invention refers to a polyester film oriented in the -axial direction, which is made from a mixture of such polyester and other thermoplastic resins as a starting material, and can be produced by any known method. For example, it is usually melt-extruded into a sheet at 270 to 320°C, then cooled and solidified at tto-go°C to form an amorphous sheet, and then biaxially stretched vertically and horizontally, or simultaneously stretched. Then, a method such as heat treatment at /1,0 to 230° C. (for example, the method described in Japanese Patent Publication No. Sho JO-stJq) can be used.

In the present invention, the sum of Young's moduli in the longitudinal and transverse directions of the polyester film thus obtained is preferably g
00 kg/mm2 or more, more preferably 90 kg/mm2 or more
0 to 9/tomo 2 or more. Also, its thickness is 0.5~30
μm1 preferably 7 to 70 μm, more preferably 2 to 6
It is μm.

In the present invention, the blending amount of different thermoplastic resins with respect to polyester is 0.02% by weight or more and less than 3% by weight. If the blending amount is 0.0.2% by weight without grooves, the surface roughness of the obtained film will be insufficient and the workability such as unwinding, winding and running properties of the film will not be satisfactory, and the transfer ink will Ribbons, which are heat-sensitive transfer materials coated with this material, tend to wrinkle. Furthermore, sticking with the thermal head is likely to occur.

On the other hand, if the blending amount is 3% by weight or more, the surface of the obtained film will be too rough and the printing properties will deteriorate. A more preferable blending amount of the thermoplastic resin is 0. /~λ, 5% by weight.

In the present invention, there is an optimum range for the amount of different types of thermoplastic resins blended into polyester, but at the same time, the center line average roughness (Ra) of the film surface is 0.02 to
It is preferably in the range of 1 μm, more preferably 0
．． / -0.1 part μm. Ra7! ＋″－
If it is less than 0.02 μm, running performance and anti-stacking properties will be insufficient, and if Ra exceeds 7 μm, printing performance will deteriorate and furthermore, the thermal head will be more likely to wear out.

A film whose surface has been roughened using a darkening organic component instead of the conventionally used inorganic particles has good slitting properties, excellent flatness, and no ink transfer to the opposite side.

Of course, in the present invention, an antistatic agent, a heat stabilizer, a small amount of inorganic particles, etc. may be added to the film as long as the purpose thereof is not impaired.

In this way, the present invention develops a sea-island structure by blending a specific amount of a specific resin into polyester, and controls the surface roughness of the film within a specific range, thereby improving runnability and stability resistance. While maintaining a high level of properties, it also satisfies the slitting property, which has been difficult to improve in the past, and its industrial value is high.

In the present invention, the type of heat-sensitive transfer layer formed on the base film is not limited, and either a non-reactive type or a reactive type can be used. Non-reactive types include, for example, transfer layers made of hot-melt ink or sublimable dyes, and reactive types include, for example, a combination of leuco dye and color developer. I can do it.

〔Example〕

The present invention will be explained in more detail below using Examples and Comparative Examples, but the present invention is not limited to the following Examples unless it exceeds the gist thereof.

In Examples and Comparative Examples, "1 part" indicates "parts by weight."

Further, the measurement method used in the present invention is as follows.

(1) Center line average roughness was determined as follows using a surface roughness meter (Sg-3FK) manufactured by Koita Research Institute. The tip radius of the stylus was 2 μm, and the load was 30 m9. Extract a portion of reference length L (2, Srrrm) from the film cross-sectional curve in the direction of its center line,
The roughness curve y=f (when expressed phantomly, given by the following formula) is expressed in μm, with the center line of this cut-out portion as the X-axis and the direction of vertical magnification as the Y-axis.

/ LL fol f(x)l dx (2) Film runnability during printing Transfer ink was applied to the mass base film. That is, a heat-melting color material layer consisting of 35 parts of paraffin wax, 30 parts of carnauba wax, low molecular weight polyethylene (left), and 2 parts of carbon black was applied to one side of the film to a dry film thickness of 5 μm. Established. Note that a silicon-based heat-resistant protective layer with a thickness of 0.3 μm was provided on the opposite side to the coloring material layer.

Next, Fuji Xerox's facsimile Telecopier 2
Using a Q-type machine, the running condition of the heat-sensitive transfer film obtained as above was evaluated and divided into the following three stages.

○...The feeding condition is good and there are no problems at all.

△...The ribbon may be slightly wrinkled.

×: The ribbon is wrinkled and the feeding condition is often poor.

(3) Stick characteristics The stain characteristics were evaluated using the same evaluation machine and film as in the evaluation of film runnability during printing, and were divided into the following three stages.

○...Good condition with no problems at all.

Δ...Slight fusion is observed.

×...Fusion often occurs, resulting in poor ribbon conveyance.

(4) Printability Printability was evaluated using the same evaluation machine and film as in the evaluation of film runnability during printing, and was divided into the following three stages.

○: No shading or bleeding (good).

Δ: Slight unevenness in shading and bleeding are observed.

×: There is clear unevenness in shading or blurring.

(5) Film slitting properties A film coated with the transfer ink and heat-resistant protective layer used to evaluate the running properties of the film during printing! ;, 000 m
The rolls were continuously slit and wound up, and the rolls were divided into three stages by observing the degree of swelling on the end face.

○... There is almost no swelling and the roll appearance is good △...
There is relatively little bulge, but the edges are slightly swollen.

×: The bulge is thick (the edges are swollen).

(6) Ink transferability A ribbon slit to a width of 1oxx and rolled was unwound and run over a length of 200°C, and stains on the guide pins in contact with the heat-resistant protective layer were observed and divided into the following three stages.

○...Almost no ink adhesion is observed.

Δ: Some ink adhesion is observed.

×: Considerable ink adhesion is observed.

Example/ Intrinsic viscosity 0. A) Polyethylene terephthalate) 99
．． Melt flow indexer 0g (9//O
min) of polypropylene/0 parts are uniformly mixed,
It was melted at 290° C. in an extruder, extruded through a T-die, and rapidly cooled to obtain an unstretched sheet.

Then, it was stretched 3.3 times in the longitudinal direction and 3.9 times in the transverse direction.
A coaxially oriented polyester film having a thickness of 3 μm was obtained by heat treatment at 30°C.

A transfer ink and a heat-resistant protective layer were applied to the obtained film, and the film was evaluated as a heat-sensitive transfer material.

These results are shown in Table 1 along with the results of other Examples and Comparative Examples.

A film was obtained in the same manner as in Example 1 except that the thermoplastic resin contained in the polyester was changed as shown in Table 1, and then evaluated as a thermal transfer material.

In Comparative Example/and Co-Example/, 0.9 parts of aluminum oxide with an average particle size of 0.5μ is used instead of 0 parts of polypropylene, or 7 parts and g parts of silicon dioxide with an average particle size of /, /μ. A film was obtained in the same manner as in Example, and then evaluated as a thermal transfer material in the same manner as in Example.

Polyester films were obtained in the same manner as in Comparative Example 3 and Example, except that the amount of polypropylene was changed to 0.01 part or 72 parts, and then evaluated as a thermal transfer material.

〔Effect of the invention〕

Thermal transfer materials using the film of the present invention have excellent properties such as running properties, staking resistance, printing properties, slitting properties, and ink transfer properties, and have high industrial value.

Claims (1)

[Claims] (1) A polyester film for thermal transfer characterized by containing 0.02% by weight or more and less than 3% by weight of a thermoplastic resin other than polyester.