JPH03199092A - Thermal transfer sheet - Google Patents

Abstract

PURPOSE:To obtain good running properties and the stability of a thermal head against heat energy by reducing printing noise and to prevent the generation of blocking during storage by providing a sticking preventing layer consisting of polyvinyl butyral, a partial hydrolysate of a silane coupling agent and a filler to the single surface of a base material. CONSTITUTION:A transfer ink layer is provided on one surface of a plastic film and a sticking preventing layer consisting of polyvinyl butyral, a partial hydrolysate of a silane coupling agent and a filler is provided on the other surface thereof. As polyvinyl butyral, one with a high polymerization degree is pref. from the aspect of heat resistance and the partial hydrolysate of the silane coupling agent is prepared by appropriately combining difunctional and trifunctional silane coupling agents and adding water and an acid or an alkaline catalyst thereto in an org. solvent. The use amount of the partial hydrolysate of the silane coupling agent is set to 5-50 pts.wt per 100 pts.wt. of polyvinyl butyral. As the filler, an inorg. particle such as talc or silica or wax such as polyethylene wax or paraffin wax is used.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a heat-sensitive transfer sheet having a transfer layer containing a heat-sublimable dye on one side of a substrate and a heat-resistant antistenking layer on the other side. .

[Conventional technology]

In recent years, on base materials such as plastic films.

A thermal transfer sheet with a heat-melting ink layer containing pigments or dyes, a sublimation ink layer containing a sublimable dye in a binder, or a heat-sensitive transfer layer containing a heat-reactive coloring component is used to print a thermal head, etc. A widely used method is to perform thermal printing according to image information using a heating means to form an image on a receiving sheet.

Conventionally, substrates for such thermal transfer sheets have a thickness of 2 to 15 mm. Plastic films such as polyester film, polyimide film, polypropylene film, aromatic polyamide film, cellulose acetate film, and cellophane are used, but among these,
Polyester film is preferably used because it is easy to form a uniform thickness, has an excellent surface smoothness, and is easy to operate in a printer.

However, thermal transfer sheets using this polyester film as a base material require high energy to obtain sufficient print density, so a so-called sticking phenomenon occurs in which the polyester itself fuses with the thermal head. In addition, due to thermal head pressure, bat pressure in the cassette for maintaining the heat-sensitive transfer sheet, or contact resistance with the roll in the printer, the running properties of the sheet become poor, resulting in irregular print density, scumming, etc. However, in severe cases, the base material may break.

In order to prevent these phenomena, 1, for example, a method of providing a metal oxide layer or an anti-friction layer made of silicon oxide on the base material (Japanese Patent Laid-Open Nos. 54-143152 and 57-74195), silicone resin. A method of providing a heat-resistant resin layer such as or epoxy resin (Japanese Patent Application Laid-Open No. 55-7467), a method of providing a resin layer to which a surfactant, etc. that is solid or semi-solid at room temperature is added (Japanese Patent Application Laid-Open No. 57-129789) Alternatively, a method of providing a heat-sensitive resin layer containing a lubricating inorganic pigment (Japanese Patent Application Laid-open No. 5
6-155794) etc. have been proposed.

However, these methods require expensive processes such as vapor deposition, use a large amount of thermal energy for thermal curing, and require long periods of time to provide sufficient heat resistance. There are problems in that it requires aging, has insufficient lubricity, and also has the disadvantage that dirt adheres to the thermal head.

Furthermore, since the heat-sensitive transfer sheet used in the above conventional method is generally stored rolled up, the heat-resistant layer and the transfer layer come into contact with each other during storage, resulting in a blocking phenomenon, which causes background smudges and image fading when printed. There was a problem that occurred.

In addition, a method using a wax that melts and exhibits lubricity as a lubricant by heat from a thermal head, such as the method of JP-A-58-187396, is used during heat absorption.

There were drawbacks such as the occurrence of a sticking phenomenon and non-feeding of the heat-sensitive transfer sheet.

Also, when processing a heat-resistant slip layer into a base material.

Because the base material is thin, drying at high temperatures causes drying wrinkles, which causes image breakage when printed. On the other hand, drying at a low temperature results in insufficient curing and has the disadvantage that sufficient heat resistance cannot be obtained.

[Problem to be solved by the invention]

An object of the present invention is to provide a thermal transfer sheet that is stable against the thermal energy of a thermal head during printing, exhibits excellent running properties, and is free from blocking.

[Means to solve the problem]

According to the present invention, a transfer ink layer is provided on one side of the plastic film, and an anti-sticking layer made of a partial hydrolyzate of polyvinyl butyral and a silane coupling agent and a filler is provided on the other side. A thermal transfer sheet is provided.

The present invention will be explained in more detail below.

The polyvinyl butyral to be contained in the anti-sticking layer of the present invention preferably has a high degree of polymerization from the viewpoint of heat resistance.For example, Denka Butyral $500OA (degree of polymerization 2000) and Denka Butyral #6000C manufactured by Denki Kagaku Kogyo Kyoku Co., Ltd.
(degree of polymerization: 2400) and Meiko Sletsku BX-1 (degree of polymerization: 1,750) manufactured by Tanemizu Chemical Industry (2) are particularly preferred.

Further, a partial hydrolyzate of a silane coupling agent is prepared by appropriately combining a difunctional silane coupling agent and a trifunctional silane coupling agent, and adding water and an acid or alkaline catalyst in a solvent.

Examples of difunctional silane coupling agents include dimedyldichlorosilane and diphenyldichlorosilane.

Dimethyldimethoxysilane, dimethyljethoxysilane, diphenyldimethoxysilane, γ-glycidoxypropylmethyljethoxysilane, N-β (aminoethyl)
γ-Aminopropylmethyldimethoxysilane and the like can be used.

In addition, trifunctional silane coupling agents include methyltrichlorosilane, phenyltrichlorosilane, methyltrimethoxysilane, phenyltrimethoxysilane, decyltrimethoxysilane, vinyltriethoxysilane, γ
-Methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane, etc. can be used.

The ratio of polyvinyl butyral and silane coupling agent partially hydrolyzed product used is 5 to 80 parts by weight of silane coupling agent partially hydrolyzed to 100 parts by weight of polyvinyl butyral.
Parts by weight, preferably 5 to 50 parts by weight. Also organotin compounds to accelerate curing.

For example, dibutyltin oxide, dibutyltin dilaurate, nibbutyltin diacetate, etc. may be added.

Fillers include inorganic particles such as talc, silica, calcium carbonate, magnesium oxide, alumina, titanium white, clay, and boron nitride, waxes such as polyethylene wax and paraffin wax, amides, esters, and salts of higher fatty acids. , fluororesin, and guanamine resin powder, and these may be used alone or in combination of two or more.

The thickness of the heat-resistant anti-sticking layer of the present invention varies depending on the feedability of the printer, applied energy, etc., but it is usually 0.05 to 3.0 μL, preferably 0.1 to 2 μL.

As the plastic film used as the base material in the present invention, those formed from various conventionally known thermoplastic resins can be used, such as polyester film and polyamide film.

polyolefin film, polycarbonate film,
Examples include cellulose films. Its thickness is usually 0.5~50. , preferably about 3 to 101 seconds.8 In the present invention, the type of the transfer ink layer formed on the base material is not limited, and a non-reactive type or a reactive type can be arbitrarily used. Examples of the reactive type include a transfer ink layer made of heat-melting ink or a transfer layer made of sublimable dye; examples of the reactive type include, for example, color-forming combinations such as those shown below. A transfer layer containing one of the reaction components of the reaction system can be mentioned.

(1) Combination of leuco dye and color developer (electron-accepting substance).

(2) Combinations of long-chain aliphatic iron salts such as ferric stearate and ferric myristate with phenols such as tannic acid, gallic acid, and ammonium salicylate.

(3) Combinations of heavy metal sulfates such as silver, lead, mercury, and thorium sulfates with sulfur compounds such as Na-tetrathionate, sodium thiosulfate, and thiourea.

(4) A combination of a noble metal salt of an organic acid such as silver behenate or silver stearate and an aromatic organic reducing agent such as protocatechuic acid, spiroindane, or hydroquinone.

(5) Combinations of organic acid lead salts such as lead caproate, lead pelargonate, and lead behenate with thiourea derivatives such as ethylenethiourea and N-dodecylthiourea.

When using a heat-sensitive transfer sheet having a reactive heat transfer layer as described above, the receiving sheet receiving the transfer is as follows:
For example, when the thermal transfer layer contains a leuco dye, a sheet having a receiving layer containing a reactive component that causes color development by reacting with the reactive component contained in the thermal transfer layer of a color-forming reaction system consisting of the above-mentioned combination is used. As the sheet, a receiving sheet containing a color developer such as a phenolic substance can be used.

Further, the color-forming reaction system consisting of a combination of the two types of reaction components described above can be contained in the thermal transfer layer in a state in which the color-forming reaction is prevented in advance. A thermal transfer sheet having a thermal transfer layer containing such a color-forming reaction component can transfer an image made of a molten deposit of a color-forming reaction product onto a paper serving as a receiving sheet by thermal transfer.

Taking a non-reactive heat-sensitive transfer layer as an example, the method for forming it is explained by hot-melt coating a composition consisting of a colorant, a binder, etc. on a film substrate, or by dispersing the composition in an appropriate melt. The coated paper can be solvent coated to form a layer of about 1 to 20 microns. As the coloring agent, any of various dyes conventionally used in the field of copy paper or pigments such as carbon black can be used, and as the binder, waxes such as carnauba wax, book wax, beeswax, etc. can be used. be able to.

〔Example〕

The present invention will be explained in more detail below based on the following examples.

Example 1 [Preparation of silane coupling agent partial hydrolyzate] 24.0 g of dimethyldimethoxysilane and 14.0 g of methyltrimethoxysilane were dissolved in a mixed solution of 32.0 g of toluene and 30.0 g of methyl ethyl ketone to give a concentration of 1.0. % sulfuric acid 3
．． 0d was added and stirred for 3 hours to perform hydrolysis.

This liquid is called liquid A.

[Anti-sticking layer composition] Part by weight: Liquid A: 4.0 dibutyltin dilaurate 0.1 boron nitride
1.0 toluene
47.0 Methyl ethyl ketone
45.5 The above Kumikaimono was applied to a 4.5 μm polyester film with a wire bar to a thickness of approximately II Ja, and dried at 100°C for 1 minute and 70°C for 1 hour to form a thermal transfer film with an anti-sticking layer. A base material for a sheet was obtained.

An ink composition having the following formulation was dissolved on this base material with stirring, and then coated on the surface opposite to the anti-sticking layer using a wire bar to a film thickness of 1 IJa to obtain an ink sheet for sublimation thermal transfer.

(Ink composition) Parts by weight Toluene 45.0 Methyl ethyl ketone 50.0 Example 2 (Anti-sticking layer composition) Parts by weight Part A 2.6 Dibutyltin dilaurate 0.1 Magnesium stearate 1.0 Toluene
47.0 Methyl ethyl ketone
46.4 The above composition was prepared as in Example 1 and 4.5. A base material for a thermal transfer sheet having an anti-sticking layer was obtained by coating a polyester film.

The ink composition of Example 1 was similarly applied to this base material to obtain an ink sheet for sublimation type thermal transfer.

Comparative Examples 1 and 2 In Examples 1 and 2, Coronate L [manufactured by Nippon Polyurethane] was used instead of Part A, which is a partial hydrolyzate of the silane coupling agent, and dibutyltin laurate, which was the catalyst, in the anti-sticking layer composition. 2.0 parts by weight and 1.3 parts by weight were added to form an anti-sticking layer in the same manner as in the example to obtain a sublimation type thermal transfer ink sheet for comparison.

The storage stability and printability of each of the heat-sensitive transfer sheets obtained above were tested. The test method and results are shown below.

[Test and results]

1. Preservation acceleration test The same two heat-sensitive transfer sheets obtained were stacked on top of each other so that the ink layer and anti-sticking layer were in contact with each other, sandwiched between two sheets of paper, and then heated at 60°C under a load of 10g (501R).
A preservation acceleration test was conducted by placing the sample in a constant temperature bath. As a result, in both Examples 1 and 2 and Comparative Examples 1 and 2, no abnormalities such as blocking or back bleed were observed.

2. Printing Test Printing was carried out under the following conditions using a partial glaze type thermal head using image receiving paper of Hitachi Video Printer VY-SO Supply VY-5100, which is an image receptor for sublimation type thermal recording, as an image receptor.

Applied power: 44 g/dot Application time: 0 to 8-sec Applied energy: 0 to 3.54 mJ/dot The thermal transfer sheets of Examples 1 and 2 have quiet printing noise and smooth feeding in the printer. .

Sticking development due to thermal energy of the thermal head did not occur at all. Furthermore, no wrinkles were observed in the solid areas after the ink was removed, and there was no image disturbance caused by the stick.

In addition, the ink sheet of Comparative Example 1 had a loud printing sound, poor feeding performance within the printer, and a sticking phenomenon occurred due to the thermal energy of the thermal head, resulting in noticeable disturbances in the printed image. Furthermore, the ink sheet of Comparative Example 2 broke at the initial stage of printing, and printing could not be performed.

〔effect〕

As explained above, the thermal transfer sheet of the present invention has an anti-sticking layer made of a partial hydrolyzate of polyvinyl butyral and a silane coupling agent and a filler on one side of the base material, so the printing sound is quiet and good. It has the advantage that it has good transportability, is stable against the thermal energy of the thermal head, does not cause sticking, and does not cause blocking during storage.

Claims (1)

[Claims] (1) A thermal transfer characterized in that a transfer ink layer is provided on one side of a plastic film, and an anti-sticking layer made of a partial hydrolyzate of polyvinyl butyral and a silane coupling agent and a filler is provided on the other side. sheet.