JPS6227188A - Transfer medium for thermal recording - Google Patents

Abstract

PURPOSE:To ensure excellent gradation properties and favorable properties of transfer onto a rough paper having poor surface properties, enable multiple times of use and obtain excellent print clearness, preservation stability, abrasion resistance and uniformity of transfer, by incorporating elastic particles in an ink layer provided on a base. CONSTITUTION:The ink layer comprises elastic particles, which is formed of a material having a tensile stress at 300% elongation (JIS-K6301) of not more than 80kgf/cm<2>. If said tensile stress exceeds 80kgf/cm<2>, gradation properties and properties of transfer onto a rough paper become poor. The elastic particles may be formed of an elastic material such as a thermoplastic elastomer, a synthetic rubber and a natural rubber, the average particle diameter thereof being preferably 0.01-10mum. If the average particle diameter is more than 10mum, rate of transfer is extremely low, whereas if it is less than 0.01mum, printed density is lowered. The elastic particles are incorporated in the ink layer in an amount of 0.5-80wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Background of the Invention Technical Field The present invention relates to a transfer medium for thermal recording.
For more information, please refer to fax, computer printer,
This invention relates to improvements in the ink layer of thermal recording transfer media for output printers of office automation equipment, various recorders, and the like.

Prior Art and its Problems In recent years, with the diversification of information, the development of thermal recording transfer media for use in facsimiles, computer printers, output printers for OA equipment, various recorders, etc. has been actively promoted.

Such thermal recording has the advantages that colored characters and images can be easily obtained by heating means, that a complicated developing process is not required, and that the hardware used is a relatively compact and simple device.

BACKGROUND ART Conventionally, so-called thermal paper of dye coloring type or metal compound type is known as a commonly used thermal recording medium.

However, recently, there has been a strong demand for image reliability, and a recording method using a thermal recording transfer medium for obtaining transferred characters and images on so-called plain paper is becoming mainstream.

The heat-sensitive recording transfer medium used in such a recording method is usually formed by providing an in layer containing a colorant and a resin on a substrate.

However, such a medium generally has a drawback in that the gradation of image density is poor with respect to the recording power input to the thermal head.

Another disadvantage is that the transferability to so-called rough paper, which has poor surface properties, is poor.

Furthermore, it has the disadvantage that it cannot withstand repeated use many times.

■ Purpose of the Invention The purpose of the present invention is to provide a material with excellent gradation, good transferability to rough paper with poor surface properties, durability for multiple uses, high print clarity, storage stability, abrasion resistance, and It is an object of the present invention to provide a transfer medium for heat-sensitive recording which has excellent transfer uniformity.

■Disclosure of invention Such objects are achieved by the invention described below.

That is, the present invention is a transfer medium for thermal recording having an ink layer on a substrate, characterized in that the ink layer contains elastic particles.

■Specific structure of the invention Hereinafter, a specific configuration of the present invention will be explained in detail.

The thermal recording transfer medium (hereinafter simply referred to as transfer medium) of the present invention has an ink layer on a substrate.

This ink layer contains elastic particles.

The elastic particle material in the present invention has a tensile stress of 300% (J
IS-6301) has physical properties of 80 kgf/cm2 or less, more preferably 10 to 50 kgf/7cm2.

If this 300% tensile stress exceeds 80 kgf/cm2, gradation and transferability to rough paper will deteriorate.

Elastic particles having such physical properties include, for example, various thermoplastic elastomers such as styrene, polyester, polyolefin, and polyurethane, butadiene rubber, styrene-butadiene rubber, isoprene rubber, and ethylene-
If you use elastic bodies such as propylene rubber, butyl rubber, chloroprene rubber, nitrile rubber, acrylic rubber, urethane rubber, silicone rubber, fluororubber, polysulfide rubber, polyether rubber, chlorosulfonated polyethylene, various synthetic rubbers, natural rubber, etc. good.

When using particles of such elastic bodies, one type of the above-mentioned elastic bodies may be used alone, or two or more types may be used as a blend.

The average particle diameter of such elastic particles is 0.01 to 1 OAA
I11, more preferably 0.1 to 4 μm. If this value exceeds 10 μm, the transfer rate will be extremely poor, and if it is less than 0.01 μm, the print density will decrease.

Such elastic particles are present in the ink layer at a concentration of 0.5 to 8
It is contained in an amount of 0 wt%, more preferably 1 to 60 wt%.

If this value exceeds 80 wt%, the print density will be low, and if it is less than 0.5 wt%, the present invention will not be effective.

In addition to these elastic particles, the ink layer usually contains dyes or pigments, and if necessary, various resins.

There are no particular restrictions on the resin contained, but among them, the resins shown below are preferred.

i) Polyolefin polyethylene, polypropylene, poly4-methylpentene-1, etc.

ii) Polyolefin copolymers such as ethylene-vinyl acetate copolymer, ethylene-acrylic ester copolymer, engineered ethylene-acrylic acid copolymer, ethylene-propylene copolymer, ethylene-butene-1 copolymer ethylene-maleic anhydride copolymer, ethylene propylene terpolymer (EPT), etc.

In this case, the polymerization ratio of the comonomers can be set arbitrarily.

1ii) Vinyl chloride copolymer, for example, vinyl acetate-vinyl chloride copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-maleic anhydride copolymer, acrylic acid ester or methacrylic acid ester and vinyl chloride copolymers with vinyl chloride, acrylonitrile-vinyl chloride copolymers, vinyl chloride ether copolymers, ethylene or propylene-vinyl chloride copolymers, ethylene-vinyl acetate copolymers grafted with vinyl chloride, etc.

In this case, the copolymerization ratio can be arbitrary.

iv) Vinylidene chloride copolymer Vinylidene chloride-vinyl chloride copolymer, bicoliden chloride-vinyl chloride-acrylonitrile copolymer, vinylidene chloride-butadiene-vinyl halide copolymer, etc.

In this case, the copolymerization ratio can be arbitrary.

■) Polystyrene vi) Styrene copolymer such as styrene-acrylonitrile copolymer (AS resin), styrene-acrylonitrile-butadiene copolymer (ABS resin), styrene-maleic anhydride copolymer (SMA resin), styrene- Acrylic acid ester-acrylamide copolymer, styrene-butadiene copolymer (
SBR), styrene-vinyritine chloride copolymer, styrene-methyl methacrylate copolymer, etc.

In this case, the copolymerization ratio can be arbitrary.

vii) Ste-1 non-type polymers such as α-methylstyrene, P-methyl, styrene, 2,5-dichlorostyrene, α.

Copolymers of β-vinylnaphthalene, α-vinylpyridine, ayanaphthene, vinylanthracene, or GJl, straw, such as α-medylstyrene and methacrylic ester (Dll, polymers).

viii) Bear Inden resin Maron-indene-styrene copolymer.

ix) Terpene resin or picolite For example, terpene resin which is a polymer of limonene obtained from α-pinene, or β-pinene 4. Picolite r7.

X) Acrylic resin Particularly preferred are those containing an atomic group represented by formula 1.

Formula R1-CH-C-1C-OR20 In the above formula, R10 represents a hydrogen atom or an alkyl group, and R211 represents a substituted or unsubstituted alkyl group.

In this case, in the above formula, R10 is preferably a hydrogen atom or a lower alkyl group having 1 to 4 carbon atoms, particularly a hydrogen atom or a methyl group. Also, R7 [
l may be a substituted or unsubstituted alkyl group, but the alkyl group preferably has 1 to 8 carbon atoms, and when R20 is a substituted alkyl group,
The substituent for the alkyl group is preferably a hydroxyl group, a halogen atom, or an amino group (particularly a dialkylamino group).

The atomic group represented by the above formula may form a copolymer with other atomic groups to form various acrylic resins, but usually, the atomic group represented by the above formula An acrylic resin is formed by forming a homopolymer or copolymer having one or more repeating units.

xi) Polyacrylonitrile xii) Acrylonitrile copolymer, for example, acrylonitrile-vinyl acetate copolymer, acrylonitrile-vinyl chloride copolymer, acrylonitrile-styrene copolymer, acrylonitrile-vinylidene chloride copolymer, acrylonitrile-vinylpyridine copolymer , acrylonitrile-methyl methacrylate copolymer,
Acrylonitrile-butadiene copolymer, acrylonitrile-butyl acrylate copolymer, etc.

In this case, the copolymerization ratio can be arbitrary.

xiii) Diacetone acrylamide polymer A diacetone acrylamide polymer obtained by reacting acrylonitrile with acetone.

xiv) Polyvinyl acetate xv) Vinyl acetate copolymers, such as copolymers with acrylic esters, vinyl ethers, ethylene, vinyl chloride, etc.

The copolymerization ratio may be arbitrary. xvi) Polyvinyl ethers such as polyvinyl methyl ether, polyvinyl ethyl ether, polyvinyl butyl ether, etc.

xvii) Polyamide In this case, polyamides include ordinary homonylons such as nylon 6, nylon 6-6, nylon 6-10, nylon 6-12, nylon 9, nylon 11, nylon 12, and nylon 13, as well as nylon 6. /6-676-1
0. Nylon 6/6-6712, nylon 6/6-67
Polymers such as No. 11 or modified nylon may also be used.

xviii) polyesters with various dibasic acids such as aliphatic dibasic acids such as oxalic acid, succinic acid, maleic acid, adipic acid, sebastenic acid, or aromatic dibasic acids such as isophthalic acid and terephthalic acid ty; Condensates and co-condensates with glycols such as ethylene glycol, tetramethylene glycol and hexamethylene glycol are suitable.

Among these, condensates of aliphatic dibasic acids and glycols and cocondensates of glycols and aliphatic dibasic acids are particularly suitable.

Furthermore, for example, a modified glybutal resin obtained by esterifying and modifying glybutal resin, which is a condensation product of phthalic anhydride and glycerin, with a fatty acid, a natural resin, etc., is also preferably used.

xix) Polyvinyl acetal resin Both polyvinyl formal and polyvinyl acetal resin obtained by acetalizing polyvinyl alcohol are preferably used.

In this case, the degree of acetalization of the polyvinyl acetal resin can be arbitrary.

xx) Polyurethane resins Thermoplastic polyurethane resins having urethane bonds, in particular polyurethane resins obtained by condensation of glycols and diisocyanates, in particular polyurethanes obtained by condensation of alkylene glycols and alkylene diisocyanates. Resins are preferred.

xxi) Polyether styrene formalin resin, ring-opening polymer of cyclic acetal, polyethylene oxide and glycol, polypropylene oxide and glycol, propylene oxide-ethylene oxide copolymer, polyphenylene oxide, etc.

xxii) Cellulose derivatives For example, various esters and ethers of cellulose, such as nitrocellulose, acetylcellulose, ethylcellulose, acetylbutylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, methylcellulose, ethylhydroxyethylcellulose, and mixtures thereof.

xxiii) polycarbonates such as polydioxydiphenylmethane carbonate,
Various polycarbonates such as dioxydiphenylbroban carbonate.

xxiv) Phionomer Na such as methacrylic acid and acrylic acid.

Li, Zn, Mg salts, etc.

×Xν) Ketone resin For example, a condensate of a cyclic ketone such as cyclohexanone or acetophenone and formaldehyde.

xxvi) Xylene resins, such as m-xylene or a condensate of mesitylene and formalin, or various modified products thereof, such as rosin modification.

xxvi i) Petroleum resins C5 type, C9 type, Cs-cg copolymer type, dicyclopentadiene type, or copolymers or modified products thereof.

In the present invention, the resins i) to xxvii) above may be used alone or in combination of two or more.

The number average molecular weight of these resins is 30,000 or less, especially 3
00 to ioooo is preferred.

Furthermore, in the ink layer, i) to xxv as described above are included.
In addition to the resin ii), it is preferable to contain an ethylene-vinyl acetate copolymer (EVA). Ethylene-
Vinyl acetate copolymer (EVA) is a thermoplastic resin obtained by copolymerizing ethylene and vinyl acetate, and its number average molecular weight is about 1,000 to 200,000.

The content of vinyl acetate is approximately 5 to 70%.

It is preferable to add about 1 to 200 parts by weight of such ethylene-vinyl acetate copolymer to 100 parts by weight of the resin described in 111f.

This improves the uniformity of image density.

There are no particular restrictions on the dyes to be contained, as in the case of the above-mentioned resins, but among the dyes, it is particularly preferable to use oil-soluble dyes.

Oil-soluble dye refers to a dye that can be dissolved in an organic solvent of 20°C at a temperature of 10 g/f1 or more, and examples of the organic solvent include alcohol-based dyes,
One or more solvents selected from aromatic, ester, ketone, and cellosolve solvents are selected and used.

Suitable oil-soluble dyes and their solubility are shown below.

The oil-soluble dye or other dye is added in an amount of about 1 to 120 parts by weight per 100 parts by weight of the resin. When the ink layer contains a pigment instead of a dye, the pigment used may be either organic or inorganic, but among these, it is particularly preferable to use the pigments shown below.

That is, such pigments include azo dye-based, anthraquinone-based, indigoid-based, soluble dye-based, sulfide-based, carbonium-based, phthalocyanine-based, quinoneimine-based, cyanine-based, nitroso-based, nitro-based, stilbene-based,
There are quinoline series, pyrazolone series, 1:2 type metal complex salt series, benzoquinone series, naphthoquinone series, etc.

In the present invention, it is mainly included to obtain color characters and images.

Therefore, it is preferable to use pigments that have been separated into other types as shown below.

(1) Red (magenta) Azo type, dyed with lake, fused polycyclic (anthraquinone, thioindigo, perinone, perylene, quinacridone, isoindolinone) alizarin lake, daylight fluorescence, specifically pigment red 57.57:1 .57:2
(Color index) For example, Br1lliant C
arnain 6B, 68 Tourner (Dainichiseika) Symulcr Brlliant (:arm
ine 6B (Dainippon Ink) Sanyo Br1lliant Carmine 6
8.68N (Yamaba dye) Sanyo Fast Re
d F6R (Yamaba dye) Sanyo LiLhol R
ubin BKN (Yamaba pigment) Graph
ol Rubin BP (Sand) R
ubin Toner 4B, 4BA (
I CI ) Vulcafor C1, aret Y
There are pigments such as (I CI ).

(2) Yellow Azo type, dyed with lake, condensed polycyclic (anthraquinone, isoindolinone, quinophthalone, isoindoline, nitroso, metal complex salt, azomethine, daylight fluorescence, specifically pigment yellow 13 (color index) For example, Benzidine Yellow 2Gn
(Dainippon Seika) Sy+nuicr Fast Yell
ow+ GRF (Dainichi Ink) Sanyo
Light, Fast Benzidine Ye
low R (Yamaba pigment) GraphoL Ye mouth a@GRBL
(Sand) Monolite Yellow GL
(ICI)Vyn
amon Yeliotll GRE
There are pigments such as (I CI ).

(3) Blue (cyan) Azo type, phthalocyanine, lake dyeing, fused polycyclic (anthraquinone), alkali blue, daylight fluorescence, specifically pigment blue 15 (color index) For example, Lionol Blue FG 7351
(Toyo Ink) Lioriol Blue FG 73
93G (Toyo Ink) Graphol B
lue 2GLS (S:/C)Mona
stral Fast Blue BG
There are pigments such as (I CX ).

(4) Black Aniline black, carbon black The average particle diameter of such pigments is about 0.005 to 10 μm, more preferably 0.01 to 4 pIl+.

Such a pigment is contained in an amount of 1 to 200 parts by weight per 100 parts by weight of the resin described above, more preferably 3 to 70 parts by weight.

Furthermore, in addition to the above-mentioned elastic particles, dyes or pigments, and optionally resins contained in the ink layer, various waxes, various pigments, various oils, various ceramic particles, various types of Polymer dispersants, plasticizers,
The stabilizer and the like may be added in an amount of 0.1 to 100 parts by weight based on the weight of the resin.

The thickness of the ink layer formed from the composition as described above is 0.5 to 20 μm, more preferably o, a-=-
It is said to be about ioμm. If the thickness exceeds 20 .mu.l, there will be problems such as decreased transfer sensitivity and loss of print clarity, and if it is less than 0.5 .mu.m, there will be problems that the printing density will not be equal to 70%.

An ink layer having such a thickness can be formed by various known layer forming methods, such as a melting method using hot melt, gravure coating, reverse roll coating, roll coating, air knife coating, di-coating, etc. A solution method such as bucoat or spinner coat may be used.

Substrates on which such ink layers are applied include polyethylene terephthalate (PET), polyethylene, polycarbonate, nylon, polyamide, polyimide, polyphenylene sulfide, polysulfone, wholly aromatic polyester, polyether ether ketone, polyether sulfone, and polyester. It is preferable to use a resin film such as etherimide.

The thickness of such a substrate is not particularly limited, but is usually about 0.8 to 20 μm.

Further, the shape of the base body is not particularly limited, and various shapes are possible.

Further, the medium of the present invention may be used for a single color or for multiple colors, and its structure may be one of various known structures.

A top coat layer containing various waxes or the like may be provided on the ink layer of the present invention.

Furthermore, A2
A back coat layer containing various metal layers such as silicone or fluororesin, various polar light or electron beam curing resins, thermosetting resins, etc. may be provided.

Further, a base layer may be provided on the ink layer.

■Specific effects of the invention In the thermal recording transfer medium of the present invention, plain paper is placed on the ink layer of the medium, and the ink layer is heated by the thermal head that contacts the back surface of the substrate of the medium and moves relatively. It is transferred onto paper.

That is, the head is heated by passing a pulse current corresponding to the thermal temperature through the thermal head for an arbitrary period of time.

The heat transmitted through the substrate melts or sublimates the ink layer, and the melted or sublimated ink layer adheres to the Juntsu paper. When the medium and plain paper are gradually peeled off, the ink layer material leaves the substrate and becomes a normal paper. transferred onto paper. In this way, characters and images are printed on plain paper.

The transfer medium for thermal recording in the present invention has an ink layer on a substrate, and this ink layer contains elastic particles.

Due to the cushioning effect of the elastic particles, the transferred characters and images remain clear even after multiple uses.

Moreover, the gradation properties are also extremely good.

In addition, it is difficult to use 5 with poor surface properties, which makes it difficult to use with ordinary media.
Even so-called rough paper can be used satisfactorily, and the transferability is also good.

(2) Specific Examples of the Invention Below, specific examples of the present invention will be shown to explain the present invention in further detail.

[Example 1] Polyethylene terephthalate (PE"l) with a thickness of 2.0 μm
Samples were prepared by using a resin film as a base, and applying various ink layers having the compositions shown below using a predetermined solvent using a gravure coating method on the base. Note that the numerical value in parentheses is the number average molecular weight of the resin.

(Ink layer composition) Weight part Ketone resin oligomer brilliant carmine 6B Toner 14 VA (molecular weight 2200, vinyl acetate 29 wt%) 14 Styrene thermoplastic elastomer (Elastomer AR 114゜manufactured by Aron Kasei Co., Ltd., 300% tensile stress) 10kgf/cm2, particle size 0.2~0
．． 4 μm) 34 1 degree (comparison) Part by weight The composition was the same as ink layer composition 1 except that the particles of the styrene thermoplastic elastomer used in ink layer composition 1 were removed.

The characteristics shown below were measured for the various samples thus prepared.

(1) Using a gradation sample, transfer recording was actually performed on a paper sheet while changing the recording power, and the relationship between the obtained optical density (OD) and recording power (W) was measured.

Read the values of recording power P0.8 b Pl, 3 corresponding to optical densities 0.8 to 1.3, respectively, and calculate the ratio of the difference between these and the above optical density as an indicator of gradation. γ.

(2) Transferability to rough paper Using the above sample, a pulse width of 1.8 m5e, c
Printing is transferred using a thermal head with an area of 100 μ■
The average value of the ratio of the area transferred to the rough paper with respect to ×200 μm was defined as the transferability to the rough paper (%).

The results are shown in Table 1.

Table 1 No. Composition y (OD/W) Transferability (%) 1 Composition 1 5. 2 8
62 (comparatively low) Composition 2 15.6 11 From the results in Table 1, the effects of the present invention are clear.

In addition, print clarity, storage stability, abrasion resistance, transferability,
It was also confirmed that the uniformity was at the same level or higher than that of conventional products.

Claims (1)

[Claims] (1) A transfer medium for thermal recording having an ink layer on a substrate, wherein the ink layer contains elastic particles.