JP2012066389A - Sublimable thermal transfer medium - Google Patents

Abstract

A sublimation type thermal transfer medium is required that a dye layer does not transfer to an image receiving paper layer by layer under any conditions. Furthermore, in order to cope with water-based image-receiving paper, it is required not to stick not only when high energy is applied from the thermal head but also when low energy is applied.
A heat-resistant resin layer 1C is provided on the back surface of a substrate 1A, and at least a dye layer 1B containing a sublimation dye in a binder is provided on the other surface, and the dye layer 1B is composed of at least two types of modified silicone oils. A release agent is added, and one modified silicone oil is a non-reactive silicone oil modified with a side chain polyether having a molecular weight of 8000 or more, and the other modified silicone oil is a side chain diamine having a molecular weight of 3000 or less. A sublimation thermal transfer medium 1 which is a modified reactive silicone oil.
[Selection] Figure 1

Description

  The present invention relates to a sublimation thermal transfer medium having good releasability from image receiving paper.

  In recent years, with the widespread use of digital cameras, the demand for full-color printers that output images taken with digital cameras has increased, and in particular, it is possible to obtain intermediate colors easily, and a sublimation type that can obtain image quality close to that of silver halide photography. The thermal transfer method has attracted attention.

  In this sublimation type thermal transfer system, a heat-resistant resin layer is provided on the back side of the substrate, and a sublimation type thermal transfer medium having at least a dye layer containing a sublimation type dye in a resin binder is used on the other side. This is a recording method in which an image is obtained by transferring sublimation dye to a recording material by applying thermal energy with a head or the like.

  In recent years, it has been required to obtain images at high speed due to the progress of recording methods, and a lot of thermal energy is applied to the sublimation thermal transfer recording medium in a short time from the thermal head, and the sublimation thermal transfer medium is heated. However, a characteristic that it does not stick to the recording material is required.

  In order to cope with such high-speed recording, those in which various release agents are added to a sublimation type thermal transfer recording medium have been developed.

  Examples of the release agent include a copolymer of silicone and polyamideimide resin, a dye-permeable release agent selected from a phosphate ester-based surfactant and a fluorinated fatty acid-modified silicone, and a polysiloxane and another resin. Copolymers and polyether-modified silicone are used (see Patent Document 1, Patent Document 2, and Patent Document 3).

  However, the above-described method has a problem that it cannot cope with water-based image receiving paper developed in recent years.

  There is a tendency for water-based image receiving paper to have a strong sticking property on the image receiving paper side, and furthermore, there is a difference in the releasability required between when high energy is applied from the thermal head and when low energy is applied during printing. Have confirmed.

  With conventional oil-based image receiving paper, it is sufficient to ensure the release performance when high energy is applied from the thermal head, so the above method is sufficient, but water-based image receiving paper has low energy. Since there is a tendency to stick even when applied, it is necessary to cope with this.

  In order to cope with the above, a method for suppressing the water content of the sublimation type thermal transfer recording medium to 2.5% or less after adding a release agent is shown. (See Patent Document 4)

  However, the above method easily imagines that the substrate, binder, etc. absorb moisture depending on the environment at the time of use, such as the addition amount of the release agent and the use of the easy adhesion layer as described in Patent Document 4. It is difficult to control only by the method.

Japanese Patent No. 3990144 Japanese Patent No. 2825229 JP 2007-84670 A JP 2010-58501 A

In the sublimation type thermal transfer medium, since it is assumed to be used in various countries around the world, it is required that the dye layer is not transferred to the image receiving paper layer by layer under any conditions.
Furthermore, in order to cope with water-based image-receiving paper, it is required not to stick not only when high energy is applied from the thermal head but also when low energy is applied.
The present invention aims to solve the above problems.

  In order to solve such a problem, in the sublimation type thermal transfer medium of the present invention, in claim 1, a dye layer comprising a heat resistant resin layer on the back surface of the substrate and a sublimation dye on the other surface in the binder. In the sublimation type thermal transfer medium comprising at least, a release agent comprising at least two kinds of modified silicone oils is added to the dye layer, and one of the modified silicone oils is modified with a side chain polyether modified with a molecular weight of 8000 or more. It is a reactive silicone oil, and the other modified silicone oil is a reactive silicone oil modified with a side chain diamine having a molecular weight of 3000 or less.

  According to a second aspect of the present invention, the dye layer further contains a curing agent.

  According to a third aspect of the present invention, the curing agent is an isocyanate resin.

  According to the present invention, in a sublimation type thermal transfer medium provided with a heat-resistant resin layer on the back surface of the substrate and at least a dye layer containing a sublimation dye in the binder on the other surface, two types of release agents are added to the dye layer. By adding it, it becomes possible to cope with the application of high energy and application of low energy.

  A normal sublimation type thermal transfer medium is composed of a three-color dye layer of a yellow dye layer, a magenta dye layer, and a cyan dye layer and an overcoat layer for protecting the printing screen. An image is formed by a combination of discharge amounts.

  Each color of the dye layer described in the present invention refers to the above-mentioned yellow dye layer, magenta dye layer, and cyan dye layer, but it is not limited to these colors in view of the characteristics of the present invention, and sublimation. Any layer that releases dye in the mold thermal transfer medium will be included.

  The release agent that exhibits an effect when high energy is applied is preferably a non-reactive silicone oil modified with a side chain polyether having a molecular weight of 8000 or more.

  The release agent that exhibits an effect when low energy is applied is preferably a reactive silicone oil modified with a side chain diamine having a molecular weight of 3000 or less.

  That the release agent has a high molecular weight or is non-reactive is effective for maintaining sufficient release performance when printing with high energy. On the other hand, low molecular weight and reactivity have the characteristic of being easily localized on the surface, and are effective for obtaining sufficient releasability even when printing at low energy.

It is a conceptual sectional view of a sublimation type thermal transfer medium of the present invention.

Hereinafter, the present invention will be described in more detail.
FIG. 1 is a conceptual cross-sectional view of a sublimation type thermal transfer medium of the present invention.
The sublimation type thermal transfer medium 1 of this embodiment has a dye layer 1B provided on the surface of a substrate 1A provided with a back coat 1C as a heat-resistant resin layer on the back surface. In this sublimation type thermal transfer medium 1, a release agent composed of two types of modified silicone oils is added as a release agent for the dye layer 1B, and one modified silicone oil is modified with a side chain polyether having a molecular weight of 8000 or more. The other modified silicone oil is characterized by a side-chain diamine-modified reactive silicone oil having a molecular weight of 3000 or less.
The non-reactive silicone oil modified with a side chain polyether having a molecular weight of 8000 or more in the present invention is a non-reactive silicone oil having a side chain modified with a polyether, and is a known material. Moreover, the molecular weight as used in the field of this invention means a weight average molecular weight. The non-reactive silicone oil provides sufficient release performance when printing with high energy. When the molecular weight is less than 8000, the effect is not exhibited. A preferred molecular weight is 10,000 or more. As the non-reactive silicone oil, a commercially available product can be used, and examples thereof include a product name EFKA3031 manufactured by BASF Corporation. The non-reactive silicone oil is preferably added in the range of 0.1 to 10% by mass in the dye layer.
Further, the reactive silicone oil modified with a side chain diamine having a molecular weight of 3000 or less in the present invention is a reactive silicone oil having a side chain modified with diamine, and is a known material. The reactive silicone oil provides sufficient release performance when printing with low energy. When the molecular weight exceeds 3000, the effect is not exhibited. A preferable molecular weight is 2000 or more. What is marketed can also utilize this reactive silicone oil, for example, Shin-Etsu Chemical Co., Ltd. make, brand name KF-393 etc. are mentioned. The reactive silicone oil is preferably added in the range of 0.1 to 10% by mass in the dye layer.

  Since the base material is required to have heat resistance and strength not to be softened and deformed by heat pressure in thermal transfer, for example, polyethylene terephthalate, polyethylene naphthalate, polypropylene, cellophane, acetate, polycarbonate, polysulfone, polyimide, polyamideimide, polyvinyl alcohol, A synthetic resin film such as aromatic polyamide, aramid, and polystyrene, and paper such as condenser paper and paraffin paper can be used alone or in combination, but the material is not limited. Among these, a polyethylene terephthalate film is preferable in view of physical properties, workability, cost, and the like. Further, the thickness can be in the range of 2 to 50 μm in consideration of operability and workability, but in consideration of handling properties such as transfer suitability and workability, the thickness is about 2 to 12 μm. preferable. Furthermore, an easy-adhesion layer for enhancing the adhesion with the dye layer and a dye diffusion preventing layer for suppressing the diffusion of the dye to the substrate side may be provided on the base material.

  As the binder for the dye layer, it is preferable from the viewpoint of heat resistance that the main component is polyvinylcetal resin. Examples of the polyvinyl acetal resin include, but are not limited to, polyvinyl butyral and polyvinyl acetoacetal. From the viewpoint of heat resistance, the degree of acetalization of the polyvinyl acetal resin is more preferably 50% or more, and further preferably the degree of acetalization of the polyvinyl acetal resin is 80% or more.

  One kind of polyvinyl acetal resin as the main component of the binder is possible, but in order to obtain heat resistance and good coating performance, it is also possible to use a combination of those having different Tg and average degree of polymerization.

  Furthermore, it is possible to crosslink the polyvinyl acetal resin using a thermosetting resin or the like as a curing agent to improve its heat resistance. In particular, isocyanate resins are preferable because of their high reactivity.

  By cross-linking the polyvinyl acetal resin with a thermosetting resin and enhancing the heat resistance, an effect of suppressing the elongation of the medium at the time of printing can be obtained, which prevents thermal wrinkles of printing defects.

  Here, the ratio of the sublimation dye and the binder in the dye layer is preferably dye / binder = 10/100 to 300/100 as a mass ratio. This is because if the dye / binder ratio is less than 10/100, the amount of dye is too small and the color development sensitivity is insufficient, and a good thermal transfer image cannot be obtained, and if this ratio exceeds 300/100, the binder This is because the solubility of the dye in the ink is extremely lowered, and the storage stability of the ink layer is deteriorated when the thermal transfer sheet is formed, and the dye is likely to be precipitated.

  The sublimation type dye used in the dye layer of the present invention is a dye that sublimates or vaporizes at 60 ° C. or higher, and may be any one that is mainly used in thermal transfer printing such as disperse dyes and oil-soluble dyes. Known sublimation dyes include CI Disperse Yellow 1, 3, 8, 9, 16, 33, 41, 42, 54, 60, 77, 116, 201, 231 and CI Disperse Red 1, 4, 6, CI Disperse Blue 3, 14, 19, 24, 26, 56, 60, 64, 72, 99, 108, 241, including 11, 15, 17, 50, 55, 59, 60, 73, 83, 111 CI solvent such as CI 354, CI Disperse Violet 26, 31, CI Solvent Yellow 14, 16, 30, 33, 56, 77, 93, 116, 179, CI Solvent Red 19, 23, 25, 27 etc. Examples include, but are not limited to, 24, 36, 63, 83, 105 of blue.

  The thickness of the dye layer in the present invention is preferably in the range of 0.3 to 1.5 μm. If the thickness of the dye layer is 0.3 μm or less, sufficient dye cannot be retained to form an image, and if it is 1.5 μm or more, the thickness of the dye layer is too thick and it may be difficult to sufficiently heat. is there.

  The dye layer of the present invention includes additives such as an ultraviolet absorber and a radical absorber, a filler for ensuring slipperiness, and an antifoaming agent for preventing foam defects in the production process in order to maintain the characteristics. It may be added arbitrarily.

  Although the heat-resistant resin layer in the present invention is not particularly limited, for example, a thermoplastic resin such as a polyester resin, a cellulose resin, and an acrylic resin having a high glass transition point; a reaction product of isocyanate and acrylic polyol, polyester polyol, urethane, and the like Isocyanate curable resin; Thermosetting resin such as epoxy-melamine curable resin and acrylic-melamine curable resin; Photo curable resin such as UV curable resin and EB curable resin. As thickness of a heat resistant resin layer, 0.3-3.0 micrometers is preferable.

  Examples of the present invention will be described below. In addition, the quantity (part) of each component described in Examples is part by weight.

Base material Polyethylene terephthalate film (thickness: 4μm, with single-sided easy adhesion layer)
Back side Back coat (Thickness: 1μm, Polyamideimide)
Dye layer thickness 0.7μm
Binder Polyvinyl acetal resin (Tg: 110 ° C., polymerization degree: 2100) 15 parts Polyvinyl acetal resin (Tg: 110 ° C., polymerization degree: 1000) 15 parts Dye
CI Disperse Blue 63 30 parts release agent Polyether-modified silicone oil
(BASF, trade name EFKA3031, side chain modified molecular weight 10,000) 0.3 part diamine modified silicone oil (Shin-Etsu Chemical Co., Ltd., trade name KF-393, side chain modified molecular weight 2000) 0.3 part solvent methyl ethyl ketone 160 parts 80 parts of toluene

Base material Polyethylene terephthalate film (thickness: 4μm, with single-sided easy adhesion layer)
Back side Back coat (Thickness: 1μm, Polyamideimide)
Dye layer thickness 0.7μm
Binder polyvinyl acetal resin (Tg: 110 ° C., polymerization degree: 2100) 13 parts polyvinyl acetal resin (Tg: 110 ° C., polymerization degree: 1000) 13 parts curing agent Isocyanate resin 4 parts dye
CI Disperse Blue 63 30 parts release agent Polyether-modified silicone oil
(BASF, trade name EFKA3031, side chain modified molecular weight 10,000) 0.3 part diamine modified silicone oil (Shin-Etsu Chemical Co., Ltd., trade name KF-393, side chain modified molecular weight 2000) 0.3 part solvent methyl ethyl ketone 160 parts 80 parts of toluene

(Comparative Example 1)
Base material Polyethylene terephthalate film (thickness: 4μm, with single-sided easy adhesion layer)
Back side Back coat (Thickness: 1μm, Polyamideimide)
Dye layer thickness 0.7μm
Binder Polyvinyl acetal resin (Tg: 110 ° C., polymerization degree: 2100) 15 parts Polyvinyl acetal resin (Tg: 110 ° C., polymerization degree: 1000) 15 parts Dye
CI Disperse Blue 63 30 parts release agent Polyether-modified silicone oil
(Manufactured by BASF, trade name EFKA3031, side chain modified molecular weight 10,000) 0.6 parts Solvent Methyl ethyl ketone 160 parts Toluene 80 parts

(Comparative Example 2)
Base material Polyethylene terephthalate film (thickness: 4μm, with single-sided easy adhesion layer)
Back side Back coat (Thickness: 1μm, Polyamideimide)
Dye layer thickness 0.7μm
Binder Polyvinyl acetal resin (Tg: 110 ° C., polymerization degree: 2100) 15 parts Polyvinyl acetal resin (Tg: 110 ° C., polymerization degree: 1000) 15 parts Dye
CI Disperse Blue 63 30 parts Release agent Diamine-modified silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., trade name KF-393, side chain modified molecular weight 2000) 0.6 parts Solvent Methyl ethyl ketone 160 parts Toluene 80 parts

(Comparative Example 3)
Base material Polyethylene terephthalate film (thickness: 4μm, with single-sided easy adhesion layer)
Back side Back coat (Thickness: 1μm, Polyamideimide)
Dye layer thickness 0.7μm
Binder polyvinyl acetal resin (Tg: 110 ° C., polymerization degree: 2100) 13 parts polyvinyl acetal resin (Tg: 110 ° C., polymerization degree: 1000) 13 parts curing agent Isocyanate resin 4 parts dye
CI Disperse Blue 63 30 parts release agent Polyether-modified silicone oil
(Manufactured by BASF, trade name EFKA3031, side chain modified molecular weight 10,000) 0.6 parts Solvent Methyl ethyl ketone 160 parts Toluene 80 parts

(Comparative Example 4)
Base material Polyethylene terephthalate film (thickness: 4μm, with single-sided easy adhesion layer)
Back side Back coat (Thickness: 1μm, Polyamideimide)
Dye layer thickness 0.7μm
Binder Polyvinyl acetal resin (Tg: 110 ° C., polymerization degree: 2100) 13 parts Polyvinyl acetal resin (Tg: 110 ° C., polymerization degree: 1000) 13 parts Curing agent Isocyanate resin 4 parts Dye
CI Disperse Blue 63 30 parts Release agent Diamine-modified silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., trade name KF-393, side chain modified molecular weight 2000) 0.6 parts Solvent Methyl ethyl ketone 160 parts Toluene 80 parts

  Six types of Examples 1 and 2 and Comparative Examples 1 to 4 having the above-described configuration are prepared, and printing is performed in two limit environments of low temperature and low humidity and high temperature and high humidity, and the performance of the sublimation type thermal transfer medium is improved. confirmed. As the image receiving paper, an image receiving paper having a receiving layer formed of water-based ink was used.

  The results of printing under a high temperature and high humidity environment of 35 ° C. and 85% Rh and confirming the printing performance when high energy is applied (hereinafter abbreviated as HE) and when low energy is applied (hereinafter abbreviated as LE) are shown below.

○: Practically sufficient performance (◎ indicates particularly high performance)
Δ: Indicates performance near the practical limit ×: Indicates performance below the practical limit

  As shown in the above table, it was confirmed that Examples 1 and 2 and Comparative Examples 1 and 3 were able to prevent HE sticking, which was a non-reactive modified with a side chain type polyether having a molecular weight of 8000 or more. It can be said that this is the effect of silicone oil.

  The results of printing under a low-temperature and low-humidity environment of 15 ° C. and 20% Rh and confirming the printing performance when applying high energy (hereinafter abbreviated as HE) and when applying low energy (hereinafter abbreviated as LE) are shown below.

  As shown in the above table, it can be confirmed that LE sticking can be prevented in Examples 1 and 2 and Comparative Examples 2 and 4, and this is a reactive silicone oil modified with a side chain diamine having a molecular weight of 3000 or less. It can be said that it is the effect of.

  From the above two test results, it was confirmed that the addition of a curing agent improved not only the resistance to thermal wrinkles but also the resistance to sticking (both LE and HE).

  According to the present invention, it is possible to provide a sublimation type thermal transfer medium excellent in printability even under conditions such as high temperature and high humidity and low temperature and low humidity.

1A: Base material 1B: Dye layer 1C: Back coat

Claims (3)

  In a sublimation type thermal transfer medium provided with a heat resistant resin layer on the back surface of the substrate and at least a dye layer containing a sublimation dye in a binder on the other surface, the dye layer is composed of at least two types of modified silicone oils. One modified silicone oil is a non-reactive silicone oil modified with a side chain polyether having a molecular weight of 8000 or more, and the other modified silicone oil is modified with a side chain diamine having a molecular weight of 3000 or less. Sublimation type thermal transfer medium, characterized in that it is a reactive silicone oil.   2. The sublimation type thermal transfer medium according to claim 1, wherein the dye layer further contains a curing agent.   The sublimation type thermal transfer medium according to claim 2, wherein the curing agent is an isocyanate resin.

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