JP2000263952A - Ink easily adherable polyester film for sublimation type thermal transfer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the dyeing property of a sublimation dye to an easily adherable layer, and at the same time, improve the adhesiveness with a sublimation ink layer and gradation property by proving an application layer wherein a moisture dispersing or water-based application liquid is applied, dried and drawn, and in addition, a heat-treatment is applied, on at least one surface of a polyester film prior to the completion of crystal orientation. SOLUTION: By providing an application layer containing an acrylic resin containing an amide group, on at least one surface of a polyester film, the adhesiveness between an ink layer comprising a sublimation dye and a resin binder, and the polyester film can be improved. In this case, the thickness of the application layer is set to a range of approx. 0.001-1 μm, and the adhesiveness with the polyester film is further improved, and thus, a blocking to be generated when the film after the application of the easily adherable layer is wound into a roll-shape, can be suppressed, and at the same time, a dyeing of the sublimation dye to the easily adherable layer is made hard to occur, and sufficient color density and gradation property can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a base film suitable for a sublimation type thermal transfer recording medium. More specifically, by having a specific coating layer, the adhesiveness to the sublimation type ink layer is excellent, and further, the adhesiveness and the dimensions of the film do not change even when heated during printing, and no wrinkles are generated. The present invention relates to a sublimation-type thermal transfer recording medium which does not transfer an ink layer to a coating layer, has little dyeability to a coating layer by a sublimation dye, and can form a transfer image excellent in gradation.

[0002]

2. Description of the Related Art Polyester film has its mechanical properties,
It has excellent properties such as dimensional stability and heat resistance, and has been used in many fields to date. One of the uses is as a base film of a thermal transfer recording material.

[0003] Among thermal transfer recording materials, the sublimation transfer recording system is in great demand as a recording system capable of easily outputting a high-quality full-color image. In the sublimation type thermal transfer, a heat sublimable dye is contained in a binder, and only the dye sublimates due to heat and is absorbed by an image receiving layer of a transfer receiving paper to form a gradation image. In order to sublimate only the dye, high adhesion between the binder and the base film is required, and it is essential that the adhesion does not decrease due to environmental changes or aging. If the adhesion is insufficient, the binder layer migrates to the transfer receiving paper, significantly impairing the gradation, and a phenomenon called overtransfer occurs. In general, polyester films are highly crystallographically oriented and have poor adhesiveness and do not adhere at all even when an ink layer is applied directly.

For this reason, physical and chemical treatments are applied to the film surface in order to increase the adhesiveness with the ink layer, but sufficient adhesiveness cannot be obtained. Further, the improvement of the adhesion by the primer treatment performed in the manufacturing process is very advantageous in terms of performance and processing, and is widely performed. A primer treatment using an aqueous coating agent such as polyester, acrylic, or urethane is known. Furthermore, since the base film is pursued to be as thin as possible, high strength is required, and dimensional change due to shrinkage due to heating during printing is also required to be small.

[0005]

However, the prior art has the following problems. General polyester, acrylic, urethane coating film of water-based coating even if the desired adhesion is obtained moisture resistance, water resistance, solvent resistance,
The blocking resistance and the like may be inferior. Furthermore, there is also a problem of the dyeability of the sublimable dye on the easily accessible layer. In recent years, high-speed printing has been promoted, and a higher temperature is instantaneously applied. Therefore, the heat resistance of the easy-contact layer and the adhesion to the ink layer when heated are required. If the adhesion is poor, the original color density and gradation are insufficient. The present invention solves these problems, has excellent adhesion to the sublimable ink layer, has no dyeability of the sublimable dye to the easy-contact layer, and provides a sublimation-type transfer image having excellent gradation. An object of the present invention is to provide an easily adhesive polyester film for thermal transfer ink.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies in view of the above problems, and as a result, have found that the above problems can be solved by using a polyester film having specific physical properties as a base material. It was completed.

In the present invention, a water-dispersible or aqueous coating solution containing an amide group-containing acrylic resin is applied to at least one surface of the polyester film before the crystal orientation is completed, and dried, stretched and further heat-treated. The invention is based on a sublimation type thermal transfer ink easy-adhesion polyester film having a coating layer.

Hereinafter, the present invention will be described in detail. The polyester constituting the polyester film of the present invention is a linear saturated polyester synthesized from an aromatic dibasic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof.

Specific examples of such polyesters include polyethylene terephthalate, polyethylene isophthalate, polybutylene terephthalate, poly (1,4-cyclohexylene dimethylene terephthalate), polyethylene 2,6-naphthalenedicarboxylate, and the like. Or a mixture of these with a small proportion of another resin. Among them, polyethylene terephthalate is preferable, and polyethylene-2,6-naphthalenedicarboxylate is more preferable if a thinner film and higher heat resistance are required.

The polyester used in the present invention contains an inorganic or organic lubricant such as silicon dioxide, calcium carbonate, kaolin, or silicone particles having a particle size of 0.1 to 5 μm.
It is better to contain 3 to 3.0% by weight, preferably 0.1 to 3.0% by weight.
1 to 1.0% by weight. By adding these lubricants, a polyester film having a center line roughness of 0.01 to 1 μm on the surface can be obtained. If the center line roughness of the film surface is less than 0.01 μm, sufficient slip properties cannot be obtained, and the film will be wrinkled and sticking of the thermal head will occur. When the center line roughness of the surface is larger than 1 μm, the thermal conductivity during printing becomes poor, and a sufficient image cannot be obtained.

The polyester used in the present invention may contain a stabilizer, a coloring agent, an antioxidant, and other additives as needed, so long as the original performance is not impaired.

The polyester film used in the present invention is obtained by melt-extruding such a polyester into a film, winding it around a casting drum, cooling and solidifying it to obtain an unstretched film. The unstretched film is taken from Tg to (Tg + 6
0) Heat to 0 ° C. and stretch in the longitudinal direction once or twice or more so that the total magnification becomes 3 to 7 times. After that, it is stretched at Tg to (Tg + 60) ° C. so that the width direction becomes 3 to 5 times, and then heat-treated at 200 to 250 ° C. for 0.1 to 10 seconds. The re-heat treatment is performed while contracting 0 to 20% or elongating 0 to 10% in the width direction.

The thickness of the polyester film used in the present invention is preferably 0.5 to 10 μm, more preferably 1 to 10 μm.
５5 μm. In recent years, there has been a demand for thinner films due to downsizing of printing equipment and speeding up of printing. As an example, the limit of the thin film of the polyethylene terephthalate film is 1.5 μm,
By using 2,6-naphthalate film, the limit of the thin film becomes 0.5 μm. When the thickness of the film is more than 10 μm, the thermal conductivity at the time of printing deteriorates, and high-speed printing cannot be performed.

The polyester film used in the present invention preferably has a thickness unevenness in the longitudinal direction and the width direction of from 0 to 10%. When the thickness unevenness is more than 10%, the back coat and the sublimation ink layer cannot be uniformly applied, and the running property at the time of printing and the resolution of printing deteriorate.

The refractive index of the polyester film used in the present invention is 1.600 to 1.800 in the longitudinal and width directions.
Is preferable. When the refractive index is smaller than 1.600, the mechanical strength is reduced, and the elongation at the time of printing is increased.
If it exceeds 0, the film tends to be torn because the degree of orientation is large.

In the present invention, a coating layer containing an acrylic resin containing an amide group is provided on at least one surface of the polyester film. This coating layer is necessary in order to improve the adhesiveness between the ink layer composed of the sublimable dye and the resin binder and the polyester film.

The thickness of the coating layer is preferably in the range of 0.001 to 1 μm, more preferably 0.01 to 0.5 μm. By setting the thickness of the coating layer to the range of 0.001 to 1 μm, the adhesiveness with the polyester film becomes good, and when the film after the application of the easy-adhesion layer is rolled, the blocking hardly occurs. Sufficient dyeing to the easily adhesive layer does not easily occur, and sufficient color density and gradation can be obtained.

The wetting index of the surface of the coating layer is 35 to 75 dyne / c.
m is preferable, and more preferably 40 to 70 dyne / cm
It is. The wetting index of the coating layer surface is 35 to 75 dyne / cm
Within the range, repelling does not easily occur when a coating solution comprising a sublimable dye and a resin binder is applied, and a uniform layer can be formed. It also has good adhesion to the ink layer.

The ring and ball softening point of the coating layer is 50 to 250 ° C.
Is more preferable, and more preferably 100 to 250 ° C. When the ring and ball softening point of the coating layer is in the range of 50 to 250 ° C, the ink layer does not peel off due to heating during printing. Further, the toughness of the coating film is improved, the adhesion between the polyester film and the coating layer becomes sufficient, the adhesiveness with the ink layer is obtained, and the ink ribbon can be easily produced.

The amide groups of the amide group-containing acrylic resin constituting the coating layer can be introduced into the acrylic resin by copolymerizing the following acrylic monomers.

For example, acrylamide, methacrylamide, N-alkylacrylamide, N-alkylmethacrylamide, N, N-dialkylacrylamide,
N-dialkyl methacrylate (as the alkyl group,
Methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-
Ethylhexyl group, cyclohexyl group, etc.), N-alkoxyacrylamide, N-alkoxymethacrylamide, N, N-dialkoxyacrylamide, N, N-dialkoxymethacrylamide (as the alkoxy group,
Methoxy group, ethoxy group, butoxy group, isobutoxy group, etc.), acryloylmorpholine, N-methylolacrylamide, N-methylolmethacrylamide, N-phenylacrylamide, N-phenylmethacrylamide and the like.

It is sufficient that the acrylic resin contains at least one kind of the monomer containing an amide group. If the amide group is not present in the acrylic resin, the adhesion to the ink layer cannot be obtained. Particularly preferred acrylic monomers containing an amide group are acrylamide, methacrylamide, N
-Alkylacrylamide, N, N-dialkylacrylamide, N, N-dialkylmethacrylate (as the alkyl group, a methyl group, an ethyl group, an n-propyl group,
Isopropyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl, cyclohexyl, etc.) and acryloylmorpholine.

The components of the acrylic resin include acrylic monomers as exemplified below. Examples of the acrylic monomer include alkyl acrylate and alkyl methacrylate (alkyl groups include methyl group, ethyl group, n
-Propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group, etc.); 2-hydroxyethyl acrylate,
Hydroxy-containing monomers such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate and 2-hydroxypropyl methacrylate; epoxy group-containing monomers such as glycidyl acrylate, glycidyl methacrylate and allyl glycidyl ether; acrylic acid;
Methacrylic acid, itaconic acid, maleic acid, fumaric acid,
Monomers containing a carboxy group or a salt thereof such as crotonic acid, styrene sulfonic acid and salts thereof (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.); acid anhydrides such as maleic anhydride and itaconic anhydride Monomers: vinyl isocyanate, allyl isocyanate, styrene, α-methylstyrene, vinyl methyl ether, vinyl ethyl ether, vinyl trialkoxysilane, alkyl maleic acid monoester, alkyl fumaric acid monoester, alkyl itaconic acid monoester, acrylonitrile, methacrylic acid Examples include monomers such as lonitrile, vinylidene chloride, ethylene, propylene, vinyl chloride, vinyl acetate, and butadiene. In addition, these monomers are exemplified, but not limited thereto. These monomers can be copolymerized using one kind or two or more kinds.

Accordingly, in a preferred embodiment of the present invention,
(A) a polyester film and (B) a repeating unit represented by the following formula (1) on at least one surface of the polyester film:
An acrylic copolymer comprising repeating units represented by the formulas (2) and / or (3) and having a total amount of the repeating units represented by the formulas (2) and (3) of 1 to 15 mol%. Sublimation type heat-sensitive transfer ink easy-to-adhere polyester film comprising a coating layer to be formed.

[0025]

Embedded image

In the formula (1), R ¹ is -H, -CH ₃ and-
It represents at least one substituent selected from the group consisting of CH ₂ OH. R ² is —COOCH ₃ or —COOC
₂ H ₅ . R ¹ and R ² may be different for each repeating unit.

In the formula (2), R ³ , R ⁴ and R ⁵ represent —H, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkylol group having 1 to 4 carbon atoms. And at least one substituent selected from the group consisting of phenyl and phenyl.
R ³ , R ⁴ and R ⁵ may be different for each repeating unit.

R ⁶ in the formula (3) is —H, carbon number 1-6.
At least one substituent selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkylol group having 1 to 4 carbon atoms, and a phenyl group. R ⁷ and R ⁸ are an alkylene group having 1 to 4 carbon atoms. R ⁶ , R ⁷ , R ⁸
May be different for each repeating unit. The preferred ratio of the repeating unit represented by the formula (2) is 2 to 10 mol%.

In the coating layer, an amide group-containing acrylic resin and other general resins such as polyester and urethane, and their modified products such as acrylic-modified polyester and acrylic-modified urethane may be mixed. More preferably, mixing with polyester is good. Therefore, in the present invention, a preferable embodiment is one in which the coating layer is composed of 5 to 60% by weight of the above-mentioned acrylic copolymer and 95 to 40% by weight of the polyester copolymer. More preferably, those comprising 30 to 60% by weight of the above-mentioned acrylic copolymer and 70 to 40% by weight of the polyester copolymer are exemplified.

Examples of the polyester copolymer include those obtained by copolymerizing terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid as an acid component, and ethylene glycol, diethylene glycol and the like as a glycol component.

A cross-linking agent such as epoxy, oxazoline or melamine may be added to these coating layers in order to further improve heat resistance. More preferred is epoxy.

The coating solution for the coating layer may contain some organic solvent as long as it does not affect the amide group-containing acrylic resin or other additives. This coating liquid can be used by adding a required amount of a surfactant such as an anionic surfactant, a cationic surfactant, or a nonionic surfactant.

As such surfactants, those which can lower the surface tension of the aqueous coating solution to 40 dyne / cm or less and promote the wetting of the polyester film are preferable. For example, polyoxyethylene-fatty acid esters, sorbitan fatty acid esters, glycerin fatty acid Esters, fatty acid metal soaps,
Examples thereof include an alkyl sulfate, an alkyl sulfonate, an alkyl sulfosuccinate, a quaternary ammonium chloride salt, an alkylamine hydrochloride, and a betaine surfactant. Further, other additives such as an antistatic agent, an ultraviolet absorber, a pigment, an organic filler, an inorganic filler, a lubricant, and an antiblocking agent can be used in combination as long as the effects of the present invention are not lost.

This coating solution is preferably applied to one or both sides of the polyester film before the crystal orientation is completed in the polyester film production process. The coating may be performed separately from the polyester film manufacturing process, but in this case, dust, dust, etc. are easily involved, and the portion becomes a defect at the time of printing, and a clean atmosphere is desirable.Moreover, a suitable film is relatively inexpensive. From these points, coating during the manufacturing process is preferred. At that time, the solid concentration of the coating solution is usually 0.1 to 30% by weight, more preferably 1 to 30% by weight.
10% by weight. The coating amount is preferably 0.5 to 50 g per 1 m ^{2 of the} running film.

As a coating method, a known method can be applied. For example, roll coating, gravure coating, roll brushing, spray coating, air knife,
An impregnation method, a curtain coating method, or the like may be applied alone or in combination.

[0036]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. Each characteristic value was measured by the following method.

(1) Thickness The weight of the film is measured and calculated from the density of the polyester.

(2) Refractive index Measured using an Abbe refractometer with sodium D line (589 nm) as a light source. The measurement is performed at 25 ° C. and 65% RH using methylene iodide as the mounting solution.

(3) Thickness of coating layer Calculated from the coating amount per 1 m ^{2 of the} coating liquid and the solid content concentration.

(4) Wetting index For the easily adhesive surface, the JIS K 6768 method was used.
23 ° C. and 50% R.C. H. Was measured under the following conditions. That is, formamide and ethylene glycol monoethyl ether were each mixed at a predetermined ratio, and 1 dyne / cm
It was prepared every other time, and a very small amount of a dye having a high degree of coloring was added to obtain a standard solution. Absorbing cotton (1
5 to 20 mg) is evenly wound around a length of 15 to 20 mm, soaked sufficiently so that the above standard solution does not drip, apply a cotton swab horizontally to the sample, and move in one direction to apply. The applied liquid film should be as wide as possible, its area should be 6 cm ² , and the application should be completed in 0.5 seconds.

(5) Ring and ball softening point The coating solution was dried to prepare a dried product, which was subjected to JIS K-253.
The softening point is measured according to 1-1960. Glycerin is used for the heating bath, and the temperature is raised at a rate of about 5 ° C./min.

(6) Adhesiveness A “backside layer” is formed on the opposite side of the easy-adhesion layer of the film.
Thereafter, an "ink layer" was formed on the surface of the easily adhesive layer to prepare a sublimation-type thermal transfer material. Using the sublimation-type thermal transfer material, a 15 cm wide and 25 cm long solid print is made on the center of an A4 size image receiving paper using a sublimation type thermal transfer recording digital color printer (“UP-D70A” manufactured by Sony Corporation). went. The state of overtransfer of the ink layer was visually observed and evaluated as follows. ；: No over-transfer of the ink layer at all △; over-transfer of the ink layer is less than 1% ×; over-transfer of the ink layer is less than 1 to 10% XX; over-transfer of the ink layer is 10% or more

"Back layer"-Back layer coating solution Esrec KS-5 (polyvinyl acetoacetal, trade name of Sekisui Chemical Co., Ltd.) 4.4 parts by weight, Vernock D-750-45 (polyisocyanate Dainippon Ink and Chemicals, Inc.) 22 parts by weight, Phosphanol RD720 (phosphate ester surfactant)
0.3 parts by weight, solvent (methyl ethyl ketone / toluene =
1/1) 73 parts by weight in coating condition dry coating so as to be 1g / m ^2, 80 ℃, dried at 1 minute. "Ink layer"-Ink layer coating solution DH / C2 (sublimable dye Nippon Kayaku Co., Ltd. product name)
4 parts by weight, Esrec KS-5 (polyvinyl acetoacetal, trade name, manufactured by Sekisui Chemical Co., Ltd.) 4 parts by weight, 92 parts by weight of a solvent (methyl ethyl ketone / toluene = 1/1) ・ Coating conditions 1 g / m ² in a dry state It is applied so as to be dried at 80 ° C. for 1 minute.

(7) Glass transition point Tg Measured using a DSC (differential scanning calorimeter) manufactured by PerkinElmer. The measuring method is as follows. Sample 10m
g was set in a DSC apparatus, melted at a temperature of 300 ° C. for 5 minutes, and then quenched in liquid nitrogen. This quenched sample is
The temperature is raised at a rate of ° C / min, and the glass transition point Tg is detected. Examples and comparative examples are shown below.

Examples 1 to 5, Comparative Example 1 o- at 25 ° C.
Polyethylene-2,6-naphthalate (containing a lubricant) having an intrinsic viscosity of 0.61 measured in chlorophenol was extruded from a T-die and quenched while electrostatically applied on a rotary cooling drum maintained at about 40 ° C. Thus, an unstretched film was obtained. Next, the unstretched film was stretched 3.6 times in the longitudinal direction at 125 ° C. to obtain a uniaxially stretched film. One side of the uniaxially stretched film was coated with a coating solution having a solid content of 4% by weight (Table 1) by a kiss coat method at 2.7 g / m ² . Next, the film was stretched 3.8 times in the width direction at 140 ° C., subjected to a tension heat treatment at 240 ° C. with a fixed length, and reheated at 240 ° C. while shrinking by 2% in the width direction. A biaxially oriented polyester film having a thickness of 2.5 μm was obtained. Table 2 shows the physical properties of the film.

Comparative Example 2 A biaxially oriented polyester film was obtained by forming a film in the same manner as in the example, except that the easy adhesion layer was not applied. Table 2 shows the physical properties of the film.

[0047]

[Table 1]

The composition of the resin in Table 1 is as follows. Acrylic A: 75 mol% of methyl methacrylate / 15 mol% of ethyl acrylate / 5 mol% of N-methylolacrylamide / 5 mol% of N, N-dimethylacrylamide
It is composed of Acrylic B: 75 mol% of methyl methacrylate / 15 mol% of ethyl acrylate / 5 mol% of N-methylolacrylamide / 5 mol% of acryloylmorpholine. Acrylic C: 80% by mole of methyl methacrylate / 20% by mole of ethyl acrylate. Polyester: 35 mol% of terephthalic acid / 12 mol% of isophthalic acid / 5 mol% of 5-sodium sulfoisophthalic acid / 45 mol% of ethylene glycol / 5 mol% of diethylene glycol Crosslinking agent: N, N, N ', N'-tetraglycidyl-m-
Xylylenediamine Wetting agent: polyoxyethylene (n = 7) lauryl ether

[0049]

[Table 2]

[0050]

As described above, the polyester film of the present invention which has excellent adhesion between the ink layer for sublimation type thermal transfer printing and the film can provide excellent images.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Satoshi Kitazawa 3-37-19 Koyama, Sagamihara-shi, Kanagawa F-term in Sagamihara Research Center, Teijin Limited (Reference) 2H111 AA01 AA27 BA07 BA53 BA61 BA62 BA71 BB06 BB08 DA02 DA04 4F100 AK25B AK25J AK25K AK41A AK41B AK41K AK42A AL05B BA02 BA10A BA10B BA15 BA16 CC00B GB90 JA04A JA20B JL11 JM01B YY00B

Claims (8)

[Claims] 1. A water-dispersible or aqueous coating solution containing an acrylic resin having an amide group is applied to at least one surface of a polyester film before the crystal orientation is completed, and dried, stretched, and further subjected to a heat treatment. Sublimation type thermal transfer ink easy adhesion polyester film. 2. The polyester film according to claim 1, wherein the thickness of the coating layer is in the range of 0.001 to 1 μm. 3. The coating layer surface has a wetting index of 35 to 75 dy.
The polyester film according to claim 1, which is in a range of ne / cm 2. 4. The ring and ball softening point of the coating layer is from 50 ° C. to 250 ° C.
The polyester film according to claim 1, which is in a temperature range of ° C. 5. The polyester film according to claim 1, wherein said polyester film is mainly composed of polyethylene terephthalate. 6. The polyester film according to claim 1, wherein said polyester film mainly comprises polyethylene-2,6-naphthalate. 7. A polyester film (A) and (B)
A repeating unit represented by the following formula (1) on at least one side thereof and a repeating unit represented by the formula (2) and / or the formula (3), and represented by the formulas (2) and (3) And a coating layer composed of an acrylic copolymer having a total amount of 1 to 15 mol%. Embedded image (In the formula (1), R ¹ represents —H, —CH ₃ and —CH ₂ OH
Represents at least one substituent selected from the group consisting of R ² is —COOCH ₃ or —COOC ₂ H ₅ . R ¹ and R ² may be different for each repeating unit. R ³ , R ⁴ , and R ⁵ in the formula (2) represent —H, and have 1 to 1 carbon atoms.
And represents at least one substituent selected from the group consisting of an alkyl group having 6 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkylol group having 1 to 4 carbon atoms, and a phenyl group. R ³ ,
R ⁴ and R ⁵ may be different for each repeating unit. R ⁶ in the formula (3) is —H, an alkyl group having 1 to 6 carbon atoms,
It represents at least one substituent selected from the group consisting of an alkoxy group having 1 to 4 carbon atoms, an alkylol group having 1 to 4 carbon atoms, and a phenyl group. R ⁷ and R ^{8 each} have 1 to 4 carbon atoms.
Is an alkylene group. R ⁶ , R ⁷ , and R ⁸ may be different for each repeating unit. ) 8. The film according to claim 7, wherein the coating layer comprises 5 to 60% by weight of the acrylic copolymer and 95 to 40% by weight of the polyester copolymer.