JPH05208566A - Dye donor material for use by thermal dye sublimation transfer - Google Patents

Abstract

PURPOSE: To provide a heat-resistant layer of a dye-donor element containing a support having on one side a dye layer and on the other side a heat-resistant layer by mixing the heat-resistant layer with a polycarbonate derived from a compound represented by a specified formula. CONSTITUTION: In a dye-donor element containing a support having on one side a dye layer and on the other side a heat-resistant layer, the dye-donor element is brought into contact with a reception sheet, is selectively heated by a thermal print head so that a dye is transferred to the reception sheet. The heat-resistant layer contains a polycarbonate derived from bis-(hydroxyphenyl)-cycloalkane(diphenol) corresponding to the formula at right. Wherein: R<1> and R<2> are each hydrogen, halogen, C1 to C8 alkyl group, C5 to C6 cycloalkyl group, C6 to C10 aryl group, C7 to C12 aralkyl respectively. X represents the necessary atoms to close a 5- to 8-membered cycloaliphatic ring.

Description

Detailed Description of the Invention

The present invention relates to dye-donor elements used by thermal dye sublimation transfer, and in particular to heat-resistant layers of said dye-donor elements.

Thermal dye sublimation transfer, also referred to as thermal dye diffusion transfer, involves placing a dye-donor element provided with a dye layer containing a sublimable dye having thermal transfer properties in contact with a receiver sheet and arranging the dye donor material in a plurality of parallel arrangements. A heat-printing head provided with a heat-generating resistor selectively heats according to a pattern information signal to transfer the dye from the selectively heated areas of the dye-donor element to a receiver sheet on which A method of recording that forms a pattern, the shape and density of which follows the intensity and pattern of the heat applied to the dye-donor element.

Dye donor materials for use by thermal dye sublimation transfer usually include a very thin support, such as a polyester support, coated on one side with a dye layer containing a printing dye. Usually, an adhesive layer or a subbing layer is provided between the support and the dye layer.

Due to the fact that the thin support softens when heated during the printing operation and sticks to the thermal print head, causing malfunctions of the printing device and poor image quality, the backside of the support (dye A heat-resistant layer is typically provided on the side opposite the layer) to facilitate passage of the dye-donor element under the thermal printing head. An adhesive layer may be provided between the support and the heat resistant layer.

The heat resistant layer generally contains a lubricious material and a binder. In conventional heat resistant layers, the binder is a hardened binder (eg EP153880, EP194106, EP).
314348, EP329117, JP-A-60-151
096, JP-A-60-229787, JP-A-60-22
9792, JP-A-60-229795, JP-A-62-4
8589, JP-A-62-212192, JP-A-62-2
59889, JP-A-1-5884, JP-A-1-5658
7, as described in JP-A-2-128899),
Alternatively, a polymer thermoplastic resin (for example, EP 267469, JP-A-58-187396, JP-A-63-191678,
JP-A-63-191679, JP-A-1-234292,
(As described in JP-A-2-70485).

The disadvantage of cured binders lies in their cumbersome production, which requires a relatively long curing time.

Polymeric thermoplastic resins known for use as binders for heat-resistant layers such as poly (styrene-co-acrylonitrile), polystyrene and polymethylmethacrylate are heat-resistant resins containing said binders. It has the disadvantage that it has a relatively low glass transition temperature (about 100 ° C.), which leads to a relatively low thermal stability of the layer, and thus to an unsatisfactory performance of said heat-resistant layer. Further, when a dye-donor element having such a heat-resistant layer is rolled up and stored for a length of time such that the backcoat of one part of the donor element is retained against the dye coating of another part, the dye Migration, resulting in density loss of prints ultimately made with the donor material.

Although polycarbonates derived from bisphenol A have higher glass transition temperatures, these polymers are not soluble in ecologically acceptable solvents such as ketones. It is preferred to use an ecologically acceptable solvent as the solvent for the heat-resistant layer coating solution.

The polycarbonates described in JP-A-62-294591 are also not soluble in ecologically acceptable solvents.

The object of the present invention is to provide a heat-resistant layer which does not have the abovementioned drawbacks.

According to the present invention there is provided a dye-donor element for use by thermal dye sublimation transfer, said dye-donor element having a dye layer on one side and a heat-resistant layer on the other side. The heat-resistant layer contains a polycarbonate derived from bis- (hydroxyphenyl) -cycloalkane (diphenol) corresponding to the following formula (I).

[0012]

[Chemical 2]

Wherein R ¹ and R ² are the same or different and are hydrogen, halogen, C ₁ -C ₈ alkyl group, C ₅ -C ₆ cycloalkyl group, C ₆ -C ₁₀ aryl group or C ₇ -C ₁₂ Represents an aralkyl group, wherein X is substituted with one or more C ₁ -C ₆ alkyl groups, or 5- or 6-membered cycloalkyl groups, or carries 5-6 fused cycloalkyl groups. A membered ring represents an atom necessary for closing an aliphatic ring.

The polycarbonate used in accordance with the present invention has a higher glass transition temperature (typically in the range of about 160 ° C to about 260 ° C) than the polycarbonate derived from bisphenol A (Tg about 150 ° C). The heat-resistant layer containing the polycarbonate exhibits better thermal stability than the heat-resistant layer containing the conventional polymer thermoplastic resin, and shows good stability of the dye-donor element when stored in a rolled or folded form. Show. Further, the polycarbonate is soluble in ecologically acceptable solvents such as methyl ethyl ketone and ethyl acetate, so a heat-resistant layer containing the polycarbonate is more conveniently and ecologically acceptable than a heat-resistant layer containing bisphenol A polycarbonate. It can be produced by any possible method.

The homopolycarbonate according to the invention has 24
It has a glass transition temperature of 0 ° C. Homopolymers of formula (I) in which X is an unsubstituted cycloaliphatic ring have a low glass transition temperature (in the range of 170 ° C.), so that the heat-resistant layer containing said polycarbonate has poor thermal stability. Furthermore, the latter polycarbonate is not soluble in methyl ethyl ketone and ethyl acetate. Accordingly, the copolycarbonates according to the invention have the formula (I) in which X is an unsubstituted cycloaliphatic ring.
It has a higher glass transition temperature than the copolycarbonate.

Preferably one or two carbon atoms of X,
More preferably only one carbon atom is dialkyl substituted. A preferred alkyl group is the methyl group, preferably the carbon atom at the α-position is not dialkyl substituted with respect to the C atom which is diphenyl substituted, alkyldisubstitution at the β-position is preferred.

Preferred examples of the diphenol used according to the present invention are those having a 5- or 6-membered cycloaliphatic ring. Examples of such diphenols are given below:

[0018]

[Chemical 3]

[0019]

[Chemical 4]

[0020]

[Chemical 5]

A particularly preferred diphenol is 1,1-bis- (4-hydroxy) -3,3,5-trimethylcyclohexane [formula (II)].

The bis- (hydroxyphenyl) -cycloalkanes corresponding to formula (I) can be prepared in a known manner by condensation of the phenol corresponding to formula (V) with the ketone corresponding to formula (VI).

[0023]

[Chemical 6]

[0024]

[Chemical 7]

In the formula, R ¹ , R ² and X have the same meanings as shown in formula (I).

The phenol corresponding to the formula (V) is a known compound and can be produced by a known method. For example, for cresol and xylenol, Verlag Ch
emie-Weinheim-New York 1978, Ullmanns
Encyklopaedie der technischen Chemie 4, neubea
rbeitete und erweiter edition, vol. 15, p. 61-77, for chlorophenol Verver Chemie 19
Published in 1975, Ullmanns Encyklopaedie der technische
Chemie 4, Vol. 9, pp. 573-582, for alkylphenols, Verlag Chemie 1979,
Ullmanns Encyklopaedie der technischen Chemie
4, 18, 191-214.

Examples of suitable phenols corresponding to formula (V) include phenol, o-cresol, m-cresol,
2,6-dimethylphenol, 2-chlorophenol,
3-chlorophenol, 2,6-dichlorophenol,
There are 2-cyclohexylphenol, diphenylphenol and o- or p-benzylphenol.

The ketones corresponding to formula (VI) are known compounds, for example Beilsteins Handbuch der Organischen Chem, Springer-Verlag 1925, Berlin.
ie Volume 7, 4th edition, and corresponding Ergaenzung sbaende1
4; Journal of American Chemical Society, 79 (1957), 1488, 1490 and 1491.
Page; US2692289; Journal of American Ch
emical Society 1954, pages 2186 and 2191
Page; Journal of Organic Chemistry Volume 38, No. 26 (1973), Page 4431; Journal of American
Chemical Society 87 (1965), 1353
See pages (especially page 1355). General methods for preparing the corresponding ketones of formula (VI) are for example VEB from Berlin.
-Deutscher Verlag der Wissenschaften, published in 1977, Organikum 15th edition, page 698.

Examples of suitable ketones corresponding to formula (VI) include 3,3-dimethylcyclopentanone, 2,2-dimethylcyclohexanone, 3,3-dimethylcyclohexanone, 4,4-dimethylcyclohexanone, 3- Ethyl-3-methylcyclopentanone, 2,3,3-trimethylcyclopentanone, 2,4,4-trimethylcyclopentanone, 3,3,4-trimethylcyclopentanone,
3,3-dimethylcycloheptanone, 4,4-dimethylcycloheptanone, 3-ethyl-3-methylcyclohexanone, 4-ethyl-4-methylcyclohexanone,
2,3,3-trimethylcyclohexanone, 2,4,4
-Trimethylcyclohexanone, 3,3,4-trimethylcyclohexanone, 2,5,5-trimethylcyclohexanone, 3,3,5-trimethylcyclohexanone,
3,4,4-trimethylcyclohexanone, 2,3
3,4-tetramethylcyclopentanone, 2,3,4
4-tetramethylcyclopentanone, 3,3,4,4-
Tetramethylcyclopentanone, 2,2,5-trimethylcycloheptanone, 2,2,6-trimethylcycloheptanone, 2,6,6-trimethylcyclopentanone,
3,3,5-trimethylcycloheptanone, 3,5,5
-Trimethylcycloheptanone, 5-ethyl-2,5-
Dimethylcycloheptanone, 2,3,3,5-tetramethylcycloheptanone, 2,3,5,5-tetramethylcycloheptanone, 3,3,5,5-tetramethylcycloheptanone, 4-ethyl -2,3,4-trimethylcyclopentanone, 2-isopropyl-4,4-dimethylcyclopentanone, 4-isopropyl-2,4-dimethylcyclopentanone, 2-ethyl-3,5,5-trimethylcyclohexanone , 3-ethyl-3,5,5-trimethylcyclohexanone, 3-ethyl-4-isopropyl-3-methylcyclopentanone, 4-s-butyl-
3,3-Dimethylcyclopentanone, 2-isopropyl-3,3,4-trimethylcyclopentanone, 3-ethyl-4-isopropyl-3-methyl-cyclohexanone, 4-ethyl-3-isopropyl-4-methylcyclohexanone , 3-s-butyl-4,4-dimethylcyclohexanone, 3-isopropyl-3,5,5-trimethylcyclohexanone, 4-isopropyl-3,5,5-
Trimethylcyclohexanone, 3,3,5-trimethyl-5-propylcyclohexanone, 3,5,5-trimethyl-5-isopropylcyclohexanone, 2-butyl-3,3,4-trimethylcyclopentanone, 2-butyl-3, 3,4-trimethylcyclohexanone, 4-butyl-3,3,5-trimethylcyclohexanone, 3-
Isohexyl-3-methylcyclohexanone, 5-ethyl-2,4-diisopropyl-5-methylcyclohexanone, 2,2-dimethylcyclooctanone and 3,3,3.
There is 8-trimethylcyclooctanone.

Examples of preferred ketones include:

[0031]

[Chemical 8]

[0032]

[Chemical 9]

[0033]

[Chemical 10]

[0034]

[Chemical 11]

[0035]

[Chemical 12]

The synthesis of suitable diphenols (I) is described, for example, in DE 3832396. Diphenol (I) is used to make the high molecular weight thermoplastic aromatic polycarbonates used according to the invention.

Homopolycarbonates can be prepared from diphenols corresponding to formula (I), but copolycarbonates can also be prepared using different diphenols corresponding to formula (I).

In the preparation of the high molecular weight thermoplastic aromatic polycarbonates for use according to the invention, the diphenol (I) may be any other diphenol not corresponding to formula (I), such as the formula HO-Z-OH (VII). It can also be used in combination with the diphenol corresponding to.

Useful diphenols of formula (VII) are Z
Is a diphenol representing an aromatic residue having 6 to 30 C atoms which can contain one aromatic nucleus or more than one aromatic nucleus. The aromatic residue Z may be substituted and may be a heteroatom or an aliphatic residue or a cycloaliphatic residue as a bond between separate aromatic nuclei [eg contained in a diphenol of formula (I) A cycloaliphatic residue] may be contained.

Examples of diphenol (VII) include hydroquinone, resorcin, dihydroxydiphenyl, bis-
(Hydroxyphenyl) -alkane, bis- (hydroxyphenyl) -cycloalkane, bis- (hydroxyphenyl) -sulfide, bis- (hydroxyphenyl) -ether, bis- (hydroxyphenyl) -ketone, bis- (hydroxyphenyl) -Sulfone, bis-
(Hydroxyphenyl) -sulfoxide, α, α′-
There is bis- (hydroxyphenyl) -diisopropylbenzene, and such compounds with alkyl or halogen substituents on the aromatic nucleus.

These and other suitable diphenols (VI
I) is, for example, US3028365, US2999983
5, US3148172, US3275651, US2
991273, US3271367, US306278
1, US2970131, US2999846, DE1
570703, DE2063050, DE206305
2, DE22111956, FR1561518 and Interscience Publishers, New York, 1964, Chemistry and Physics of Polycarbonates:

Other preferred diphenols (VII) include:
4,4'-dihydroxydiphenyl, 2,2-bis-
(4-hydroxyphenyl) -propane, 2,4-bis- (4-hydroxyphenyl) -2-methylbutane,
1,1-bis- (4-hydroxyphenyl) -cyclohexane, α, α′-bis- (4-hydroxyphenyl)
-P-diisopropylbenzene, 2,2-bis- (3-
Methyl-4-hydroxyphenyl) -propane, 2,2
-Bis- (3-chloro-4-hydroxyphenyl) -propane, bis- (3,5-dimethyl-4-hydroxyphenyl) -methane, 2,2-bis- (3,5-dimethyl-4-hydroxyphenyl) ) -Propane, bis- (3,
5-dimethyl-4-hydroxyphenyl) -sulfone,
2,4-bis- (3,5-dimethyl-4-hydroxyphenyl) -2-methylbutane, 1,1-bis- (3,5
-Dimethyl-4-hydroxyphenyl) -cyclohexane, α, α'-bis- (3,5-dimethyl-4-hydroxyphenyl) -p-diisopropylbenzene, 2,2
There are -bis- (3,5-dichloro-4-hydroxyphenyl) -propane and 2,2-bis- (3,5-dibromo-4-hydroxyphenyl) -propane.

A particularly preferred diphenol (VII) is
2,2-bis- (4-hydroxyphenyl) -propane, 2,2-bis- (3,5-dimethyl-4-hydroxyphenyl) -propane, 2,2-bis- (3,5-dichloro-4) -Hydroxyphenyl) -propane, 2,2
-Bis- (3,5-dibromo-4-hydroxyphenyl) -propane and 1,1-bis- (4-hydroxyphenyl) -cyclohexane.

Especially, 2,2-bis- (4-hydroxyphenyl) -propane (bisphenol A) is preferable.

The introduction of bisphenol A into the polycarbonate of the present invention reduces the brittleness of the polycarbonate. This causes a low degree of scratching of the heat resistant layer. However, the introduction of bisphenol A lowers the glass transition temperature compared to homopolycarbonate. A compromise must be found between scratches and thermal stability.

One diphenol (VII) can be used in combination with diphenol (I), or two or more of the above diphenols (VII) can be used with diphenol (I).

When a diphenol corresponding to formula (I) is used in combination with another diphenol in the production of the polycarbonate according to the invention, the amount of diphenol of formula (I) in the mixture of diphenols is at least It is 2 mol%, preferably at least 5 mol%, more preferably at least 10 mol%. The amount of diphenol (I) in the mixture is 25 to 75 mol%, and further 40 to 60 mol%.
Is preferred.

High molecular weight polycarbonates can be prepared by methods known to those skilled in the art of preparing carbonates. Different diphenols can be introduced into the polycarbonate in different blocks or the different diphenols can be randomly distributed.

Branching agents can be used in the preparation of the polycarbonates used according to the invention. To obtain a branched polycarbonate, small amounts, preferably 0.05 to 2.0 mol% (relative to diphenol) of tri- or high-functional compounds, especially compounds having 3 or more phenolic groups, are added. Examples of useful branching agents having 3 or more phenolic groups are phloroglucin, 4,6-dimethyl-2,4,6-
Tri- (4-hydroxyphenyl) -heptene-2,
4,6-Dimethyl-2,4,6-tri- (4-hydroxyphenyl) -heptane, 1,3,5-tri- (4-hydroxyphenyl) -benzene, 1,1,1-tri-
(4-hydroxyphenyl) -ethane, tri- (4-hydroxyphenyl) -phenylmethane, 2,2-bis-
[4,4-bis- (4-hydroxyphenyl) -cyclohexyl] -propane, 2,4-bis- (4-hydroxyphenyl-isopropyl) -phenol, 2,6-bis- (2-hydroxy-5'- Methylbenzyl) -4-
Methylphenol, 2- (4-hydroxyphenyl)-
2- (2,4-dihydroxyphenyl) -propane, orthoterephthalic acid hexa- [4- (4-hydroxyphenyl) -isopropyl] -phenyl ester, tetra-
(4-hydroxyphenyl) -methane, tetra- [4-
There are (4-hydroxyphenyl-isopropyl) -phenoxy] -methane and 1,4-bis-[(4 ', 4 "-dihydroxytriphenyl) -methyl] -benzene.

Examples of other trifunctional compounds are 2,4-dihydroxybenzoic acid, trimesic acid, cyanuric chloride and 3,3-bis- (3-methyl-4-hydroxyphenyl) -2-oxo-2. , 3-dihydroindole.

In order to terminate the chain extension to control the molecular weight of the polycarbonate, the monofunctional compound is used in a concentration which is normally known as known to the person skilled in the art.
Useful compounds such as phenol, there is t- butylphenol and other C ₁ -C ₇ alkyl-substituted phenols. Particularly, a small amount of phenol corresponding to the following formula (VIII) is useful.

[0052]

[Chemical 13]

In the formula, R represents a branched C ₈ and / or C ₉ alkyl group. Preferably the proportion of CH ₃ protons in the alkyl residue R is 47~89%, CH- and CH ₂ -
The proportion of protons is 53-11%. Alkyl residue R
Is preferably in the o- and / or p-position relative to the OH group, in particular the ortho substitution is at most up to 20%. The compounds used to terminate chain extension are generally used in concentrations of 0.5 to 10 mol%, preferably 1.5 to 8 mol%, based on the diphenol content.

The polycarbonate used according to the invention can be produced by the interfacial polycondensation method known to the person skilled in the art (Interscience Publ. 1964, Poly).
Chemistry by H. Schnell, merReviews Volume IX, page 33.
and Physics of Polycarbonates). According to this method, diphenol is dissolved in the aqueous alkaline phase. For the production of copolycarbonates, a mixture of diphenols of formula (I) and other diphenols is used. To control the molecular weight, compounds that terminate chain extension (eg compounds of formula VIII) can be added. The condensation reaction takes place in the presence of an inert organic phase containing phosgene. Preferably the organic phase used is an organic phase capable of dissolving the polycarbonate. Reaction temperature is 0 ℃
-40 ° C.

When using branching agents, they can be added to the aqueous alkaline phase together with the diphenol in an amount of 0.05 to 2 mol%, or they can be added to the organic phase before the phosgenation takes place. You can

In addition to diphenols, their mono- and / or bischlorocarbonate esters can also be used and are added in the form of solutions in organic solvents. The amount of chain terminator and branching agent is based on the amount of diphenol structural units. When using chlorocarbonate esters, the amount of phosgene can be reduced as is known to those skilled in the art.

Suitable organic solvents for dissolving the chain terminators, branching agents and chlorocarbonate esters include, for example, methylene chloride, chlorobenzene, acetone, acetonitrile and mixtures of these solvents, especially mixtures of methylene chloride and chlorobenzene. is there. If desired, the chain terminator and branching agent are dissolved in the same solvent.

As organic phase for the interfacial condensation, for example methylene chloride, chlorobenzene and mixtures of methylene chloride and chlorobenzene are used.

Examples of the aqueous alkaline phase include aqueous Na
Use OH solution.

The production of polycarbonates by the interfacial polycondensation method can be catalyzed by the addition of a catalyst such as a tertiary amine, especially a tertiary aliphatic amine such as tributylamine or triethylamine, as is known to those skilled in the art. Is 0.05 to 10 mol% based on the diphenol content
Used in an amount of. The catalyst can be added before the start of phosgenation, during phosgenation or after phosgenation.

Separation of the polycarbonate is carried out as known to those skilled in the art.

The polycarbonates used according to the invention can be prepared in a homogeneous phase by known methods (the so-called pyridine method) or else by known melt transesterification methods, for example using diphenyl carbonate instead of phosgene. Here too, the polycarbonate is separated by methods known to those skilled in the art.

The molecular weight Mw of the polycarbonate is preferably
Is at least 8000, preferably 8000-2000
00, more preferably 10,000 to 80,000.

The diphenol-derived polycarbonate according to formula (I) is used as a binder in the heat-resistant layer of the dye-donor element according to the invention in an amount of at least 10% by weight, preferably in an amount of 30-100% by weight. Used in. Mixtures of two or more of the above polycarbonates in the heat resistant layer can also be used.

In addition to the polycarbonates described above, the heat-resistant layer of the dye-donor element according to the invention may be one or more conventional thermoplastic binders for heat-resistant layers such as poly (styrene-co-acrylonitrile), poly (vinyl alcohol). -Co-butyral), poly (vinyl alcohol-co-acetal), poly (vinyl alcohol-co-benzal), polystyrene, poly (vinyl acetate), cellulose nitrate, cellulose acetate propionate, cellulose acetate hydrogen phthalate, cellulose Copolymers of acetate, cellulose acetate butyrate, cellulose triacetate, ethyl cellulose, poly (methyl methacrylate), and methyl methacrylate can also be included. Poly (styrene-co-acrylonitrile) is preferred.

Further, the heat-resistant layer of the dye-donor element according to the present invention contains a lubricating material such as a surfactant, a liquid lubricant, a solid lubricant or a mixture thereof. Surfactants are known to those skilled in the art such as carboxylates, sulfonates, phosphates, aliphatic amine salts, aliphatic quaternary ammonium salts, polyoxyethylene alkyl ethers, polyethylene glycol fatty acid esters, fluoroalkyl C ₂ -C ₂₀ fatty acids. Can be any surfactant. Examples of liquid lubricants include silicone oils, synthetic oils, saturated hydrocarbons and glycols. Examples of solid lubricants include various higher alcohols such as stearyl alcohol, fatty acids and fatty acid esters. Particularly preferred lubricants are polysiloxane-polyether copolymers and polytetrafluoroethylene. Suitable lubricants are eg US Pat.
US4916112, US4717711, US471
7712, US4866026, US4829050. The amount of lubricant used in the heat-resistant layer depends largely on the type of lubricant, but is generally about 0.1 to 50% by weight of the binder or binder mixture used, preferably 0.
It is in the range of 5 to 40% by weight.

The heat-resistant layer according to the invention can be treated with other additives without causing it to impair the anti-blocking properties of the heat-resistant layer, and with such materials scratching, eroding, fouling or otherwise damaging the printhead. Or if it does not impair the image quality.
Suitable additives are described in EP389153.

The heat-resistant layer of the thermal dye sublimation transfer donor material according to the present invention preferably comprises a polymeric thermoplastic binder or binder mixture, a lubricant, and other optional ingredients in a suitable solvent or solvent mixture, each component Is dissolved or dispersed to form a coating composition, which is applied to a support (which may be provided with an adhesive layer or a subbing layer first) and dried to form.

The heat-resistant layer of the dye-donor element can be coated on the support or printed thereon by a printing method such as a gravure method.

The heat-resistant layer thus formed has a thickness of about 0.1-3 μm.
m, preferably 0.3-1.5 μm.

As described above, a lubricant can be mixed in the heat resistant layer. However, a further top layer containing at least one lubricant is preferably coated on the heat-resistant layer. Preferably, the upper layer of the polyether-polysiloxane copolymer is coated on the heat-resistant layer from the non-solvent for the heat-resistant layer. Another preferred overlayer containing a lubricant is European Patent Application No. 9220.
No. 0229.0.

A subbing layer is preferably provided between the support and the heat-resistant layer in order to promote the adhesion between the support and the heat-resistant layer. As a subbing layer any subbing layer known to the person skilled in the art for dye-donor elements can be used. Suitable binders which can be used for the subbing layer include polyester resins, polyurethane resins, polyesterurethane resins, modified dextrans, modified celluloses and, for example, vinyl chloride, vinylidene chloride, vinyl acetate, acrylonitrile,
It can be selected from the group of copolymers containing repeating units such as methacrylate, acrylate, butadiene and styrene [eg poly (vinylidene chloride-co-acrylonitrile)]. Suitable subbing layers are eg EP13848
3, EP227090, US4567113, US45
72860, US4717771, US455927
3, US4695288, US4727057, US4
737486, US4965239, US475392
1, US4895830, US4929592, US4
748150, US4965238 and US49652
41. Preferably the subbing layer is EP43
Further described is an aromatic polyol such as 1,2-dihydroxybenzene as described in US Pat.

Any dye can be used in the dye layer of the dye-donor element of the invention provided the dye can be transferred to the dye-receiving layer by the action of heat. Examples of suitable dyes are eg EP43
2829, EP400706, European Patent Application No. 9
0203014.7, European Patent Application No. 9120
0218.5, European Patent Application No. 9120079.
No. 1.1 and the references cited therein.

The amount ratio of dye or dye mixture to binder is 9: 1 to 1: 3 by weight, preferably 2: 1 to 1: 2 by weight.
Is.

The following can be used as polymeric binders for the dye layer: cellulose derivatives such as ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxycellulose, ethyl hydroxyethyl cellulose,
Hydroxypropyl cellulose, methyl cellulose, nitrocellulose, cellulose acetate formate, cellulose acetate hydrogen phthalate, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate pentanoate, cellulose acetate benzoate, cellulose triacetate; vinyl resins and Derivatives such as polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, poly (vinyl butyral-co-vinyl acetal-co-vinyl alcohol), polyvinyl pyrrolidone, polyvinyl acetoacetal, polyacrylamide; polymers and co-derived from acrylate and acrylate derivatives. Polymers such as polyacrylic acid, polymethylmethacrylate Doo and styrene - acrylate copolymer; polyester resins; polycarbonates; poly (styrene - co - acrylonitrile); polysulfones; polyphenylene oxide; organosilicone example polysiloxanes, epoxy resins and natural resins such as gum arabic. Cellulose acetate butyrate or poly (styrene-co-acrylonitrile) is preferably used as the binder for the dye layer of the present invention.

The dye layer may also contain other additives such as a thermal solvent, a stabilizer, a curing agent, a preservative, organic or inorganic fine particles, a dispersant, an antistatic agent, a defoaming agent and a viscosity control agent.
These and other ingredients are EP 133011, EP 133
012, EP 111004 and EP 279467 are more fully described.

As a support for the dye-donor element, it is dimensionally stable and can withstand temperatures comprised up to about 400 ° C. for up to 20 ms, and typically for such short periods of time. Transfer to the receiver sheet within 1-10 milliseconds, so any material can be used as long as it is thin enough to transfer the heat applied on one side through it to the dye on the other side. Can be used. Such materials include polyester such as polyethylene terephthalate, polyamide,
Polyacrylate, polycarbonate, cellulose ester, fluorinated polymer, polyether, polyacetal,
Includes polyolefins, polyimides, glassine paper and condenser paper. Preferred is a support containing polyethylene terephthalate. Generally, the support has a thickness of 2 to 30 μm. The support may also optionally be coated with an adhesive or subbing layer. Suitable subbing layers are eg EP 4334
96, EP311841, EP268179, US47
27057, US Pat. No. 4,695,288.

In order to improve the dye transfer density by preventing the transfer of the dye towards the support in the bad direction,
A dye barrier layer containing a hydrophilic polymer can also be used in the dye-donor element between its support and the dye layer. The dye barrier layer can contain any hydrophilic material that is useful for the intended purpose. Generally good results have been obtained with gelatin, polyacrylamide, polyisopropylacrylamide,
Butyl methacrylate grafted gelatin, ethyl methacrylate grafted gelatin, ethyl acrylate grafted gelatin, cellulose monoacetate, methyl cellulose, polyvinyl alcohol, polyethyleneimine, polyacrylic acid, a mixture of polyvinyl alcohol and polyvinyl acetate, a mixture of polyvinyl alcohol and polyacrylic acid. , Or a mixture of cellulose monoacetate and polyacrylic acid. Suitable dye barrier layers are eg EP 227091 and EP 22806.
5 are described. Certain hydrophilic polymers such as EP
227091 also has suitable adhesion to the support and dye layers, thus obviating the need for a separate adhesive or subbing layer. Thus, these particular hydrophilic polymers used in the donor element in the form of a single layer perform a dual function and are therefore referred to herein as dye barrier / subbing layers.

The support for the receiver sheet for use with the dye-donor element can be, for example, a transparent film of polyethylene terephthalate, polyether sulfone, polyimide, cellulose ester or polyvinyl alcohol-co-acetal. The support can also be reflective, such as baryta-coated paper, polyethylene-coated paper, or white polyester or white pigmented polyester. A blue colored polyethylene terephthalate film can also be used as a support.

In order to avoid bad adsorption of the transferred dye to the support of the receiver sheet, this support must be coated on a special surface, the dye image receiving layer, in which the dye can easily diffuse. The dye receiving layer is, for example, polycarbonate, polyurethane, polyester, polyamide, polyvinyl chloride, poly (styrene-co-acrylonitrile),
It can contain polycaprolactone or mixtures thereof.
Suitable dye receiving layers are eg EP133011, EP13
3012, EP144247, EP227094, EP
228066. The dye-receiving layer may also contain a cured binder such as the thermoset product of poly (vinyl chloride-co-vinyl acetate-co-vinyl alcohol) and polyisocyanate.

To improve the lightfastness and other stability of the recorded images, UV absorbers, singlet acid scavengers such as HA
LS compounds (hindered amine light stabilizers) and / or antioxidants can be incorporated into the receiving layer.

The dye image-receiving layer of the receiver sheet or the dye layer of the dye-donor element can also contain a release agent that aids in separating the dye-donor element from the dye-receiving element after transfer. The release agent can also be applied in a separate layer on at least part of the dye layer or the receiving layer. Solid waxes, fluorine- or phosphate-containing surfactants and silicone oils are used as release agents. Suitable releasing agents are described in, for example, EP133012, JP-A-60-19138 and EP227092.

The thermal dye sublimation transfer printing process places the dye layer of the donor element in face-to-face relationship with the dye-receiving layer of the receiver sheet,
Imagewise heating from the back of the donor element. Dye transfer is accomplished by heating at a temperature of about 400 ° C. for about a few milliseconds.

When this method is performed only for a single color,
A monochrome dye transfer image is obtained. Multicolor images can be obtained by using donor elements containing dyes of three or more primary colors, followed by the processing steps described above for each color. The sandwich of donor material and receiver sheet is formed in three cases during the time of applying heat by the thermal printing head. After the first dye is transferred, each material is peeled off. The second dye-donor element (or another area of the donor element with a different dye area) is then brought in register with the dye-receiving element and the process is repeated. The third color and optionally more colors are obtained in the same way.

In addition to thermal heads, laser light, infrared flash or heated pens can be used as the heat source for supplying thermal energy. Thermal printing heads that can be used to transfer dye from the dye-donor elements of the invention to the receiver sheet are commercially available. If laser light is used, the dye layer or another layer of the dye-donor element must contain a compound that absorbs the light emitted by the laser and converts it to heat, such as carbon black.

Alternatively, the support of the dye-donor element can be an electrically resistive ribbon consisting of, for example, a multilayer structure of carbon-filled polycarbonate coated with a thin aluminum film. An electric current is electrically targeted to the printhead electrodes and injected into the resistive ribbon, resulting in highly localized heating of the ribbon below the corresponding electrode. In this case, heat is generated directly in the resistive ribbon, and thus that it is a hot ribbon, that the various elements of the thermal head must be hot and must be cooled before the head can be moved to the next printing position. Resistive ribbon / compared to thermal head technology
The use of electrode head technology provides inherent advantages in print speed.

The following examples are provided to illustrate the invention in greater detail, but not to limit it.

Example A dye-donor element for use by thermal dye sublimation transfer was made as follows:

5 in methyl ethyl ketone as solvent
% By weight of dye A, 3% by weight of dye B, 3% by weight of dye C, 2.5% by weight of octanediol as hot solvent and 6% by weight of poly (styrene-co-acrylonitrile) as binder. A containing solution was made. From this solution, a layer having a wet thickness of 10 μm was coated on a 6 μm thick polyethylene terephthalate film provided with a conventional subbing layer. The formed layer was dried by evaporating the solvent.

[0090]

[Chemical 14]

[0091]

[Chemical 15]

[0092]

[Chemical 16]

On the back side of the polyethylene terephthalate film was provided a subbing layer coated from a solution in methyl ethyl ketone containing each component as shown in Table 1 below. In Examples Nos. 1 and 21, no undercoat layer was provided between the support and the heat-resistant layer.

On top of said subbing layer, a binder (the types and amounts of which are given in Table 1) and 1% by weight of polysiloxane polyether copolymer (TEGOGLIDE 410 supplied by Goldschmidt) as lubricant are contained. A heat resistant layer was provided by coating from a solution in methyl ethyl ketone.

A receiving material for use by thermal dye sublimation transfer was made as follows.

7.2 g / m ² of poly (vinyl chloride-co-vinyl acetate-co-vinyl alcohol) on a 175 μm thick polyethylene terephthalate film (VINYLITE supplied by Union Carbide).
VAGD), 0.72 g / m ² of diisocyanate (DESMODUR VL supplied by Bayer AG)
And 0.2 g / m ² of hydroxy-modified polydimethylsiloxane (TEGOMER supplied by Goldschmidt
A receiving layer containing H SI 2111) was provided.

The dye-donor element was printed in combination with the receiving element on a Mitsubishi Color Video Printer CP100E.

The color of the image obtained when the receiver sheet is separated from the dye-donor element and the quality of the image obtained is repeated several times overprinting resulting in reduced sharpness of the transferred image and scratches on the image. Color drift was evaluated by visual check. Further, after printing, damage to the heat-resistant layer was checked by visual inspection for scratches and turbidity (a measure for the heat stability of the heat-resistant layer).

Defects in the performance of the heat-resistant layer result from intermittent movement rather than continuous movement across the thermal head, which results in color shift. Furthermore, the adhesion of the heat resistant layer to the thermal head causes damage to the heat resistant layer. Scratches are also induced in the images obtained on the donor and receiver materials when the worn or melted portions from the backcoat accumulate on the thermal head.

The back side of the non-print donor element (the side containing the heat resistant layer) was subjected to a tape adhesion test. A small piece of clear tape was pressed firmly by hand onto an area of the donor material. The removal of the backing layer with the tape when the tape was pulled apart by hand was checked as a measure of the adhesion between the support and the heat resistant layer. Ideally there is no backing layer removed.

The stability of the non-printed donor element in rolled or folded form depends on whether the dye was transferred from the dye layer to the heat-resistant layer by storing the donor element in the rolled form at 60 ° C. for 1 hour. Inspected by checking.

For all of the above visual ratings, the following classifications were set: bad (P), clean (F), good (G) and excellent (E).

This experiment was repeated for each dye-donor element shown in Table 1 below. The amounts in Table 1 are given in weight% in the coating solution (added to 100% solvent).

The results are shown in Table 2.

Table 1 Example No. Heat Resistant Layer Undercoat Comparison B1 13% B10 1% + B11 1.5% 1 B2 13% 2 B2 13% B10 1% + B11 1.5% 3 B2 13% B2 1% + B11 1.5% 4 (*) B2 6.5% + B1 6.5% B5 1% + B11 1.5% 5 (*) B2 4% + B1 9% B5 1% + B11 1.5% 6 (*) B2 4% + B1 9% B6 1% 7 (*) B313 13 % B5 1% + B11 1.5% 8 (*) B3 13% B6 1% + B11 1.5% 9 (*) B3 13% B6 1% 10 (*) B3 6.5% + B1 6.5% B5 1% + B11 1.5% 11 B4 13% B10 1% + B11 1.5% 12 B4 6.5% + B1 6.5% B10 1% + B11 1.5% 13 B4 13% B4 1% + B11 1.5% 14 (**) B4 13% B7 1% 15 (**) B4 13% B81 % 16 ( **) B4 13% B8 1% + B11 1.5% 17 B4 13% B6 1% 18 B4 13% B6 1% + B11 1.5% 19 (**) B4 13% B9 1% 20 (*) B4 13% B5 1% + B11 1.5% 21 (*) B4 13%

B1 = poly (styrene-co-acrylonitrile) = Luran 388S supplied by BASF

B2 = polycarbonate derived from 65 mol% bisphenol A and 35 mol% diphenol (II)

B3 = polycarbonate derived from 45 mol% of bisphenol A and 55 mol% of diphenol (II)

B4 = polycarbonate derived from 100 mol% of diphenol (II)

B5 = Copolyester = Vitel PE222 supplied by Goodyear

B6 = poly (vinylidene chloride-co-
Acrylonitrile) = S supplied by Dow Chemical
aran F310

B7 = organic titanate = Tyzor AA supplied by DuPont

B8 = organic titanate = Tyzor TPT supplied by DuPont

B9 = organic titanate = Tyzor DC supplied by DuPont

B10 = Polyurethane = Desmocoll 540 supplied by Bayer

B11 = 1,2-dihydroxybenzene

(*) = Dye layer does not contain octanediol

(**) = subbing layer coated from a solution in isopropanol instead of methyl ethyl ketone

Table 2 Example No. Tape test Color shift Scratch Heat stability Preservation comparison G G F P P P 1 P G F E G 2 P G F E G G 3 F G G G E G 4 E G G G G G 5 E G G F F 6 E F G F F 7 E E E E E 8 E F G G E G 9 E F G G E G 10 G G G G 11 P G F G E G 12 G G G G G G G E E 14 F G G E G 15 F G F E G 16 F G G E E 17 E G E E E G 18 E F E E E G 19 F G E E G G 20 G G G E G P 21 E F

From the above results the following can be seen:

When a conventional thermoplastic resin is used as a binder for the heat-resistant layer (comparison), the heat-resistant layer has poor thermal stability and the donor material has a low glass transition temperature (110 ° C.). Worse (diffusion of dye and thermal solvent from dye layer to heat-resistant layer);

Thermal and storage stability are improved when the polycarbonates according to the invention are used as binders for heat-resistant layers;

When the undercoat layer was not provided between the support and the heat-resistant layer (Examples Nos. 1 and 21), the adhesion of the heat-resistant layer to the support was poor and the slack formation of the heat-resistant layer during printing was obtained. It causes scratches in the statue.

Front page continued (72) Inventor Emile Auguste Verdonck, Septerrato, Belgium Mortzeer 27 In Agfa Gewert Namrose Rose Bennnotchup (72) Inventor, Luc Alban Van Stain, Septzelt, Belgium 27 Agfa Gewert Namrose Rose Bennault Chap

Claims (15)

[Claims] 1. A dye-donor element for use by thermal dye sublimation transfer comprising a support having a dye layer on one side and a heat-resistant layer on the other side, wherein the heat-resistant layer is of the formula (I) ] (In the formula, R ¹ and R ² are the same or different and each represents hydrogen, halogen, a C _{1 to} C ₈ alkyl group, a C _{5 to} C ₆ cycloalkyl group, a C _{6 to} C ₁₀ aryl group or a C _{7 to} C ₁₂ aralkyl group. And X is one or more C ₁ -C ₆ alkyl groups or 5
Substituted with a 6- or 6-membered cycloalkyl group or carrying a condensed 5- or 6-membered cycloalkyl group 5
A dye containing a polycarbonate derived from bis- (hydroxyphenyl) -cycloalkane (diphenol) corresponding to (representing the atoms necessary to close a 4- to 8-membered cycloaliphatic ring). Donor material. 2. A dye-donor element according to claim 1, wherein X represents the atom necessary to close the 5- or 6-membered cycloaliphatic ring. 3. A dye-donor element according to claim 2, wherein X is a dialkyl group substituted in the β-position to the phenyl-substituted C atom. 4. A diphenol corresponding to formula (I) is 1,
1-bis- (4-hydroxyphenyl) -3,3,5-
Dye-donor element according to claim 3, characterized in that it is trimethylcyclohexane. 5. The dye-donor element according to claim 4, wherein the polycarbonate is a homopolycarbonate. 6. The polycarbonate comprises a diphenol corresponding to formula (I) and a formula (VII) HO-Z-OH (VII), wherein Z may be substituted and a separate aromatic nucleus. 6 to 30 C atoms which may contain a heteroatom or a cycloaliphatic residue or an aliphatic residue as a bond between and which can contain one aromatic nucleus or more than one aromatic nucleus. Dye-donor element according to any one of claims 1 to 5, characterized in that it is derived from a diphenol corresponding to (which represents an aromatic residue). 7. A diphenol corresponding to formula (VII) is
Dye-donor element according to claim 6, characterized in that it is 2,2-bis- (4-hydroxyphenyl) -propane. 8. Dye-donor element according to claim 6, characterized in that the amount of diphenol corresponding to formula (I) in the mixture of diphenols is from 25 to 75 mol%. 9. The amount of polycarbonate derived from diphenol corresponding to formula (I) in the heat-resistant layer is at least 1.
Dye-donor element according to any one of claims 1-8, characterized in that it is 0% by weight. 10. The dye-donor element according to claim 1, wherein the heat-resistant layer further contains a lubricant. 11. A top coating containing a lubricant is coated on the heat-resistant layer.
The dye-donor element of any one of 0. 12. Dye-donor element according to claim 10 or 11, characterized in that the lubricant is a polysiloxane-polyether copolymer. 13. The undercoat layer is provided between the support and the heat-resistant layer, according to any one of claims 1 to 12.
Item Dye Donor Material. 14. The subbing layer contains poly (vinylidene chloride-co-acrylonitrile) or polyester or an organic titanate.
Dye donor material. 15. The dye-donor element according to claim 13, wherein the undercoat layer further contains an aromatic polyol.