JP3198669B2 - Easy adhesion polyester film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an easily adhesive polyester film. More specifically, the present invention relates to an easily-adhesive polyester film which is excellent in adhesiveness and blocking resistance and is suitable as a base film used for magnetic recording materials, various photographic materials, packaging materials, electric insulating materials, general industrial materials and the like. Particularly, the present invention relates to an easily adhesive polyester film suitable as a base film used for a magnetic recording material.

[0002]

2. Description of the Related Art Polyesters, especially polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate or poly-1,4-cyclohexane dimethylene terephthalate and polyesters based on these have excellent physical and chemical properties. , Fibers, films or sheets, and molded products thereof.

[0003] In particular, polyester films have excellent heat resistance, chemical resistance, and mechanical properties, so that they are used in many applications such as magnetic recording materials, various photographic materials, packaging materials, electrical insulating materials, and general industrial materials. Used.

In these applications, the polyester film is not used alone, and various coatings such as a magnetic paint, a chemical mat paint, a diazo photosensitive paint, a gelatin composition, a heat sealing composition, Used by applying or printing ink or the like.

[0005] In particular, films used for magnetic tapes and floppy disks are required to have flatness and smoothness for high reliability and high density of magnetic recording. There is a strong demand for improved adhesive strength. However, when an adhesive force to the magnetic paint is applied to the film, blocking occurs between the films, and various workability is deteriorated and magnetic recording performance is deteriorated. For this reason, in order to impart the adhesiveness of the film, a method which does not cause a blocking phenomenon between the films, and which is resistant to various solvents contained in various coatings applied or printed on the film surface. And an easily adhesive substance is desired.

However, since the polyester itself is generally inert and has poor adhesiveness, various coatings such as a magnetic paint, a chemical mat paint, a diazo photosensitive paint, a gelatin composition, a heat sealing composition,
When applying or printing ink, etc., in order to improve the adhesiveness with the coating, the film surface is subjected to physical treatment such as corona discharge or plasma, or chemical treatment using alkali or amine chemicals. There is known a method of performing an appropriate treatment, and a method of coating an easily adhesive substance. However, the physical or chemical surface treatment method complicates the process, not only increases the cost, but also does not provide sufficient adhesiveness.

On the other hand, the method of coating an easily adhesive substance can be carried out in the process of producing a polyester film, is advantageous in cost, and can select an adhesive substance which can cope with various coatings. is there. Further, from the viewpoints of handleability of the polyester film and workability during the production of the film, various water-dispersed or water-soluble copolyesters and lamination or coating of the copolyester on the polyester film have been proposed. For example, Japanese Patent Publication No. 47-40873 and Japanese Patent Application Laid-Open No. 50-1
Japanese Patent Application Laid-Open No. 50-83497 and Japanese Patent Application Laid-Open No. 54-83497 disclose a copolymer of polyester with polyethylene glycol and a metal salt compound of sulfonic acid forming an ester.
JP-A-3848, JP-A-56-144150,
JP-A-57-70153, JP-A-57-7017
JP-A No. 7 and JP-A-59-1215318 include those obtained by copolymerizing an ester-forming sulfonic acid metal salt compound and an aliphatic dicarboxylic acid component, and those obtained by laminating or coating a polyester film.

[0008]

However, the above-mentioned prior art has the following problems. That is, conventional water-dispersed or water-soluble copolymerized polyesters and those obtained by laminating or applying the copolymerized polyester to a polyester film are used for the purpose of improving the water-dispersed or water-soluble properties, with an ester-forming metal salt compound of sulfonic acid and polyethylene glycol or fatty acid. Although there are those in which an aliphatic dicarboxylic acid component and the like are used in combination, water dispersion or water solubility is not sufficient, or polyethylene glycol, because a large amount of an aliphatic dicarboxylic acid component is copolymerized,
Although the glass transition temperature of the polyester is remarkably lowered and adhesiveness is exhibited, there are drawbacks such as poor blocking resistance and solvent resistance of the film and reduced workability.

The present invention is intended to solve these drawbacks and to provide an easily-adhesive polyester film which is excellent in water solubility, adhesiveness, blocking resistance and the like and is suitable as a base film used for magnetic recording materials and the like. .

[0010]

An object of the present invention is to provide at least one surface of a polyester film as an acid component with at least 70% by mole of two or more aromatic dicarboxylic acids and 0.01 to 8 aliphatic dicarboxylic acids. Mol% and 8 to 25 mol% of an ester-forming sulfonic acid alkali metal salt compound, as a glycol component, an aliphatic glycol having 2 to 8 carbon atoms or an alicyclic glycol having 6 to 16 carbon atoms
An easy-adhesive polyester film characterized by laminating a water-soluble copolymerized polyester comprising -99 mol% and 1-20 mol% of diethylene glycol as an easy-adhesion layer is used as the gist thereof.

The water-soluble copolymerized polyester to be laminated on the polyester film surface of the present invention must contain at least 70 mol% of two or more aromatic dicarboxylic acids as an acid component, preferably at least 80 mol%. Is preferred because of excellent adhesiveness, water solubility and solvent resistance. When the content of two or more aromatic dicarboxylic acids is less than 70 mol%, the blocking resistance and the solvent resistance are poor. The aromatic dicarboxylic acid is not particularly limited, for example, terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, diphenyl dicarboxylic acid, aromatic dicarboxylic acids such as diphenyl ether dicarboxylic acid, and the like. Two or more aromatic dicarboxylic acids can be appropriately selected from among them. Preferred aromatic dicarboxylic acids are terephthalic acid, isophthalic acid and naphthalenedicarboxylic acid. Of these, two or more aromatic dicarboxylic acids are preferably selected. Particularly preferred two or more aromatic dicarboxylic acids are terephthalic acid and isophthalic acid.

The ratio of the two or more aromatic dicarboxylic acids in the present invention is not particularly limited, but the total amount of one or more aromatic dicarboxylic acids to one aromatic dicarboxylic acid is not limited. Is preferably in a molar ratio of 0.001 to 0.1, more preferably 0.005 to 0.05.
It is preferable from the viewpoint of excellent adhesiveness, water solubility and solvent resistance.

Further, the aliphatic dicarboxylic acid in the present invention needs to be 0.01 to 8 mol%, preferably 0.05 to 5 mol%, from the viewpoint of adhesiveness. If the aliphatic dicarboxylic acid is less than 0.01 mol%, the adhesiveness is poor,
If it exceeds 8 mol%, the adhesion is good, but the blocking resistance and the solvent resistance are poor. The aliphatic dicarboxylic acid is not particularly limited, but includes, for example, adipic acid, sebacic acid, azelaic acid, dodecadionic acid, and dimer acid, among which preferred aliphatic dicarboxylic acids include adipic acid, Sebacic acid and azelaic acid. Two or more of these aliphatic dicarboxylic acids may be used in combination.

In the water-soluble copolymerized polyester of the present invention, it is necessary that the ester-forming sulfonic acid alkali metal salt compound is contained in an amount of from 8 to 25 mol%, preferably from 10 to 20 mol%, based on all acid components. More preferably, 11 to 1
5 mol%. If the amount of the ester-forming sulfonic acid alkali metal salt compound is less than 8 mol%, sufficient water solubility and adhesiveness cannot be obtained. On the other hand, if it exceeds 25 mol%, the adhesiveness reaches saturation, and conversely, the blocking resistance and the solvent resistance decrease. The ester-forming sulfonic acid alkali metal salt compound is not particularly limited, but may be, for example, sulfoterephthalic acid, 5-sulfoisophthalic acid, 2-sulfoisophthalic acid, 4-sulfoisophthalic acid, 4-sulfonaphthalene-2, Examples thereof include alkali metal salts such as 6-dicarboxylic acid and esters thereof.
-Lithium, sodium and potassium salts of sulfoisophthalic acid and sulfoterephthalic acid are more preferably used.

The glycol component of the water-soluble copolymerized polyester of the present invention comprises 80 to 99 mol% of an aliphatic glycol having 2 to 8 carbon atoms or an alicyclic glycol having 6 to 16 carbon atoms;
The content of diethylene glycol must be 1 to 20 mol%. Preferably, it is 82.5 to 95 mol% of an aliphatic glycol having 2 to 8 carbon atoms or an alicyclic glycol having 6 to 16 carbon atoms, and 5 to 17.5 mol% of diethylene glycol;
More preferably, it is an aliphatic glycol having 2 to 8 carbon atoms or an alicyclic glycol having 6 to 16 carbon atoms in an amount of 85 to 92.5 mol% and diethylene glycol in an amount of 7.5 to 15 mol%. Aliphatic glycol having 2 to 8 carbon atoms or 6 to 6 carbon atoms
When the content of the alicyclic glycol of No. 16 is less than 80 mol% or the content of diethylene glycol exceeds 20 mol%, the blocking resistance and the solvent resistance are inferior. On the other hand, when the content of the aliphatic glycol having 2 to 8 carbon atoms or the alicyclic glycol having 6 to 16 carbon atoms exceeds 99 mol%, or the content of diethylene glycol is less than 1 mol%, the blocking resistance is good, but the adhesion is good. Poor sex.

The aliphatic glycol having 2 to 8 carbon atoms or the alicyclic glycol having 6 to 16 carbon atoms according to the present invention includes, for example, ethylene glycol, 1,2-propanediol,
1,3-propanediol, neopentyl glycol,
1,3-butanediol, 1,4-butanediol,
Glycols such as 1,5-pentanediol, 1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, and 1,4-cyclohexanedimethanol can be exemplified. Preferred aliphatic glycol having 2 to 8 carbon atoms or 6 to 8 carbon atoms
As the alicyclic glycol of 16, ethylene glycol,
Neopentyl glycol, 1,4-butanediol,
1,4-cyclohexanedimethanol, more preferably ethylene glycol, 1,4-butanediol and 1,4-cyclohexanedimethanol. These glycols may be used alone or in combination of two or more.

The water-soluble copolymerized polyester of the present invention may be copolymerized with an oxyacid or a polyoxyalkylene glycol within a range not to impair the effects of the present invention. May be copolymerized.

The method for producing the water-soluble copolymerized polyester laminated on the polyester film of the present invention includes, for example, terephthalic acid, isophthalic acid, adipic acid, 5-sodium sulfoisophthalic acid component as an acid component and ethylene glycol and diethylene glycol as a glycol component. The water-soluble copolyester consisting of terephthalic acid, isophthalic acid, adipic acid,
A direct esterification reaction of sodium sulfoisophthalic acid and ethylene glycol or diethylene glycol, or a transesterification reaction of dimethyl terephthalate, dimethyl isophthalate, dimethyl adipate, dimethyl 5-sodium sulfoisophthalate and ethylene glycol or diethylene glycol. A method in which the reaction product of the first step is subjected to a polycondensation reaction with the second step to produce a polycondensation reaction may be used.

At this time, as a reaction catalyst, conventionally known alkali metals, alkaline earth metals, manganese, cobalt, zinc, antimony, germanium, titanium compounds and the like are used. good.

The intrinsic viscosity of the water-soluble copolymerized polyester to be laminated on the polyester film of the present invention is not particularly limited, but is preferably 0.3 or more, more preferably 0.35 or more from the viewpoint of adhesion. 0.4 or more is preferable.

If necessary, a flame retardant, a heat stabilizer, an ultraviolet absorber, an organic lubricant such as a pigment, a dye, a fatty acid ester, a wax, or an antifoaming agent such as polysiloxane can be added to the water-soluble copolymerized polyester. Clay, mica, titanium oxide, calcium carbonate, kaolin, wet and dry silica, colloidal silica, calcium phosphate, barium sulfate, inorganic particles such as alumina, and further for the purpose of imparting slipperiness, etc. Acrylic acids,
Organic particles or the like containing styrene or the like as a constituent may be blended.

The water-soluble copolymerized polyester laminated on the polyester film of the present invention is dissolved in water and used as an aqueous solution. This aqueous solution does not have strictness in a physical or chemical sense, and includes an aqueous solution which is mostly dissolved in water and partially finely dispersed.

The higher fatty acid wax in the present invention is:
Although it is a known compound and not particularly limited, it is preferable that the main component is a fatty acid ester compound composed of a higher fatty acid having 17 to 33 carbon atoms and a polyhydric alcohol having 17 to 33 carbon atoms. Specific examples include waxes such as shellac wax, bran wax, insect wax, wool wax, carnauba wax, montan wax, candelilla wax, synthetic wax, and the like, in which some or all of the fatty acid esters of these waxes are replaced with other alcohol components, or sodium , Alkali metal salts such as potassium, or calcium, magnesium,
Modified products modified to a metal salt such as an alkaline earth metal such as barium may be mentioned. These may be in the form of an aqueous dispersion using an emulsifier, or may be in the form of a fine powder.

The mixing ratio of the water-soluble copolymerized polyester (A) and the higher fatty acid wax (B) in the present invention is A / B = 100 / 0.1-30, preferably 10 in terms of solid content ratio.
The range is from 0/1 to 20, more preferably from 100/3 to 15 (parts by weight). When B is less than 0.1 part by weight with respect to A, the effect of improving the blocking is poor.
If it is more than the part, the adhesiveness becomes poor, which is not preferable.
In addition, a known silane coupling agent or the like is added to the easy-adhesion layer as another component, for example, 1/5 to 1/15 of the higher fatty acid wax.
It may be mixed to the extent.

The particles to be added to the mixture of the water-soluble copolymerized polyester and the higher fatty acid wax in the present invention are not particularly limited as long as they impart slipperiness. Examples include inorganic particles such as titanium oxide, calcium carbonate, kaolin, wet or dry silica, colloidal silica, calcium phosphate, barium sulfate, and alumina, and organic particles containing acrylic acid, styrene, or the like as a component. Among them, from the fineness of the particles, the dispersibility of the particles, the particle size distribution, the durability of the particles and the surface smoothness and surface flatness of the obtained easily adhesive film, organic particles of crosslinked acrylic / crosslinked polystyrene, colloidal silica, etc. Is preferred,
Particularly, organic particles of crosslinked acrylic / crosslinked polystyrene are preferable. The particle size of the particles is not particularly limited, but may be 5 to 100 from the surface roughness and slipperiness of the obtained easily adhesive layer film.
0 nm, preferably 10-500 nm, more preferably 20-200 nm. The added amount of the particles is 1 to 3 with respect to 100 parts by weight of the solid content of the water-soluble copolymerized polyester.
0 parts by weight, preferably 2 to 20 parts by weight, more preferably 3 to 10 parts by weight. If the added amount of the particles is 1 part by weight or less, the effect of imparting slipperiness is poor. On the other hand, if the amount is 30 parts by weight or more, although the slipperiness is good, the adhesiveness and the surface smoothness are unfavorably deteriorated. The thickness of the easy-adhesion layer is not particularly limited, but is in the range of 0.001 to 1 μm, preferably 0.05 to 0.1 μm. The center line average roughness (Ra) of the easy-adhesion layer is 0.001 to 0.1 μm.
m, preferably 0.001 to 0.05 μm, more preferably 0.001 to 0.01 μm. The thickness of the easy-adhesion layer can be measured by various methods.For example, the cross section of the laminated film can be measured by an electron microscope, and when the easy-adhesion layer can be removed by a solvent or the like, the removed portion and the removed portion are not removed. It can also be obtained from the step of the part.

The polyester constituting the polyester film in the present invention is produced by esterification or transesterification of a dicarboxylic acid or an ester-forming derivative thereof with glycol and a polycondensation reaction. The type of polyester is not particularly limited as long as it can be formed into a film. It is preferable to use an aromatic dicarboxylic acid as a dicarboxylic acid component as a suitable polyester that can be formed into a film, for example,
Polyethylene terephthalate, polyethylene-p-oxybenzoate, polyethylene-1,2-bis (2-chlorophenoxy) ethane-4,4'-dicarboxylate, polyethylene-1,2-bis (phenoxy) ethane-4,4 ' -Dicarboxylate, polybutylene terephthalate, polyethylene-2,6-naphthalate, poly-1,4-cyclohexane dimethylene terephthalate, and the like. Among them, polyethylene terephthalate is most preferable in consideration of quality, economy, and the like. . Therefore, polyethylene terephthalate (hereinafter P)
It is called ET. ) Will be described as a representative example of polyester. Of course, these polyesters may be homopolyesters or copolyesters, and the components to be copolymerized include various aromatic dicarboxylic acid components, aliphatic dicarboxylic acids, oxycarboxylic acids and various glycols. . Known additives to the polyester constituting the polyester film, for example, flame retardants, heat stabilizers, ultraviolet absorbers, pigments, dyes, fatty acid esters, organic lubricants such as wax or defoaming agents such as polysiloxane, Is clay, mica, titanium oxide, calcium carbonate, kaolin, wet and dry silica and even colloidal silica for the purpose of imparting slipperiness,
Inorganic particles such as calcium phosphate, barium sulfate, and alumina, as well as organic particles containing acrylic, styrene, silicon, and the like as components may be blended.

It is preferable that the polyester film in the present invention is biaxially oriented from the viewpoint of mechanical and thermal properties when the easily adhesive layer is laminated. For example, the polyester is dried, melt-extruded into an unstretched sheet, then biaxially stretched and heat-treated to produce a film. The biaxial stretching may be any of longitudinal and transverse sequential stretching or simultaneous biaxial stretching, and the stretching ratio is not particularly limited, but usually 2.0 to 5.0 times each in the longitudinal and transverse directions. Alternatively, after stretching in the vertical and horizontal directions, the film may be stretched again in any of the vertical and horizontal directions. The thickness of the polyester is not particularly limited, but is preferably 2 to 200 μm.

The method of laminating the easy-adhesion layer of the easily-adhesive polyester film of the present invention is most preferably a method in which the film is applied during the production process of the polyester film and stretched together with the base material. For example, the melt-extruded polyester film before crystal orientation is stretched about 2.5 to 5 times in the longitudinal direction, a surface to be continuously applied is subjected to corona discharge treatment, and a coating liquid is applied to the treated surface. The applied film is dried while passing through a stepwise heated zone, and is stretched about 2.5 to 5 times in the width direction. Further, it is obtained by a method of being continuously guided to a heating zone at 150 to 250 ° C. to complete the crystal orientation. The coating solution used in this case is preferably an aqueous solution in view of environmental pollution and explosion-proof properties. As a method of coating on the substrate film, a known coating method, for example, a reverse coating method, a gravure coating method, a rod coating method, a die coating method, a wire bar method, or the like can be used. Known additives in the easy-adhesion layer within a range that does not impair the effects of the present invention, such as heat stabilizers, oxidation stabilizers, weather stabilizers, ultraviolet absorbers,
Organic lubricants, pigments, dyes, organic or inorganic fine particles,
A filler, an antistatic agent, a nucleating agent and the like may be blended.

Next, the method for producing the easily adhesive polyester film of the present invention will be described, but the present invention is not limited thereto. After drying the PET according to a conventional method, it is melt-extruded, and the extruded sheet-like melt is cooled and solidified to produce an unstretched PET film. 80-1
It is heated to 20 ° C. and stretched 2.0 to 5.0 times in the longitudinal direction to obtain a uniaxially oriented film. One surface of the film is subjected to a corona discharge treatment, and an aqueous coating material of the present invention diluted to a predetermined concentration with water is applied to the treated surface. Next, the coated film is stretched 2.5 to 5.0 times in the width direction while being heated to 90 to 140 ° C., and subsequently 160 to 240
It guides into a heat processing zone of ° C, and performs heat processing for 1 to 10 seconds. During this heat treatment, a relaxation treatment of 3 to 12% may be performed in the width direction as necessary. By applying a coating agent according to the application on the easy-adhesion layer side of the easily-adhesive polyester film thus obtained, various applications, for example, magnetic recording materials,
Substrate film for inorganic inks such as cellophane ink, offset ink, UV curable ink and other ink printing, electrophotographic toner easy adhesion, chemical mat paint easy adhesion, diazo paint easy adhesion, vapor deposition etc. It is preferably used as

[0030]

[Method for measuring physical properties and method for evaluating effects] The method for measuring characteristic values and the method for evaluating effects according to the present invention are as follows.

(1) Intrinsic viscosity (η) of copolymerized polyester: Measured at 25 ° C. using an o-chlorophenol solvent.

(2) Water solubility of copolymerized polyester 2 g of copolymerized polyester was placed in 100 g of water,
After stirring and dissolving at 2 ° C. for 2 hours, the mixture was cooled and filtered with a 2 μm filter. The water solubility of the copolymerized polyester was determined based on the dissolved state and the amount of the filtrate.

○: The aqueous solution was transparent or slightly cloudy, but almost no filtrate was observed.

Δ: The aqueous solution was slightly cloudy, and a filtered product was observed.

X: Hard to dissolve, or the aqueous solution was strongly cloudy, and a large amount of filtered product was observed.

(3) Adhesion An aqueous solution of a copolymerized polyester and wax is applied on a polyester film substrate, and an easy-adhesion layer is provided. A magnetic paint (Diferacoat CAD-430) is applied to the easy-adhesion layer surface.
1: A coating consisting of 100 parts by weight of Dainichi Seika Kogyo Co., Ltd.) and 1 part by weight of Sumidur N75 (manufactured by Sumitomo Bayer Co., Ltd.) as a curing agent was applied with a bar coater so as to have a thickness of 5 μm after drying. And dried at 100 ° C. for 5 minutes to form a coating layer. Cellophane adhesive tape (Nichiban Co., Ltd.)
And passed through a nip roll having a linear pressure of 50 kg / cm, and then rapidly peeled in a 180 ° direction. At that time, the area of the coated surface adhered to the cellophane pressure-sensitive adhesive tape was determined to determine the adhesiveness.

A: The area of the coated surface adhered to the cellophane adhesive tape is less than 5%, and the adhesiveness is excellent.

：: The area of the coated surface adhered to the cellophane adhesive tape is 5% to less than 10%, and the adhesiveness is slightly excellent.

Δ: The area of the coated surface adhered to the cellophane adhesive tape is less than 10 to 30%, and the adhesiveness is slightly poor.

C: The area of the coated surface adhered to the cellophane adhesive tape is 30% or more, and the adhesiveness is poor.

(4) Blocking resistance The film provided with the easy-adhesion layer was obtained by laminating the surfaces of the easy-adhesion layer and by laminating the surface of the easy-adhesion layer and the biaxially oriented PET film (overlap area: 3 cm × 4 cm). 50
After leaving for 24 hours at 50 ° C. and 85% RH under a load of 0 g / 12 cm ² , the shearing stress of the overlapped portion was measured at a tensile speed of 20 cm / min using a Tensilon tensile tester, and judged according to the following criteria.

[0042] ^{○: 0kg / cm 2 ~1kg /} cm 2 or less ^{△: 1kg / cm 2 ~3kg /} cm 2 or less ×: 3kg / cm ² or more

(5) Solvent resistance An aqueous solution of a copolymerized polyester and wax is applied on a polyester film substrate, and an easy-adhesion layer is provided. Methyl ethyl ketone, toluene, and acetone are respectively dropped as organic solvents on the easy-adhesion layer surface to easily adhere. Was observed in a cloudy state.

○: Almost no cloudiness.

Δ: slightly cloudy

X: cloudy

(6) Friction Resistance (Static Friction Coefficient μs, Dynamic Friction Coefficient μd) The friction coefficient between films is ASTM-D-1894.
According to 63, the static friction coefficient μs and the dynamic friction coefficient μd were measured. In general, the range that is considered to be excellent in slipperiness is, in a thin film having a thickness of about 10 μm, 1.0 μs or less in μs.
Preferably it is 0.7 or less.

(7) Thickness of Coating Layer Using a transmission electron microscope model HU-12 manufactured by Hitachi, Ltd., an ultra-thin section of the laminated film was observed to determine the thickness.

(8) Surface roughness (Ra) According to JIS-B-0601, using a stylus type surface roughness meter BE-3E manufactured by Kosaka Laboratory Co., Ltd., a cutoff of 0.0
The average surface roughness (μm) was measured at 25 mm and a measurement length of 4 mm.

[0050]

Next, the present invention will be described in detail with reference to examples.

Example 1 78.7 parts by weight of dimethyl terephthalate, 2.8 parts by weight of dimethyl isophthalate, 2.5 parts by weight of dimethyl adipate, and dimethyl 5-sodium sulfoisophthalate.
0 parts by weight, 59.9 parts by weight of ethylene glycol, 40 parts by weight of diethylene glycol and 0.1 parts of calcium acetate
Parts by weight, 0.3 parts by weight of lithium acetate and 0.03 parts by weight of antimony trioxide were added, and the mixture was subjected to a transesterification reaction according to a conventional method, and then 0.05 parts by weight of trimethyl phosphate was added. Then, the temperature is gradually raised and reduced, and finally 280 ° C.
A polycondensation reaction was performed at 1 mmHg or less to obtain a water-soluble copolymerized polyester. The composition of the obtained polyester is NM
As a result of measurement by R ( ^13C -NMR spectrum), the acid components were 82 mol% of terephthalic acid, 3.0 mol% of isophthalic acid, 3.0 mol% of adipic acid, 12 mol% of 5-sodium sulfoisophthalic acid, and glycol component. Is 87 mol% of ethylene glycol and 13 mol% of diethylene glycol
Met. The intrinsic viscosity was 0.57 (dl / g).

2 g of the obtained water-soluble copolymerized polyester was placed in 100 g of water, stirred and dissolved at 80 ° C. for 2 hours, cooled, and filtered with a 2 μm filter to obtain an aqueous solution of a water-soluble copolymerized polyester. The aqueous solution of the water-soluble copolymerized polyester was almost transparent, and no filtrate was observed.

On the other hand, intrinsic viscosity of 0.60 (dl / g) containing 0.2% by weight of silicon dioxide having an average particle size of 0.2 μm.
After sufficiently drying the polyethylene terephthalate chip, it was supplied to an extruder, melted at 290 ° C., extruded from a T-type die into a sheet, and cooled and solidified with a cooling drum at 25 ° C. to obtain an unstretched film. In order to improve the adhesion between the sheet and the surface of the cooling drum during this time, a wire electrode was arranged on the sheet side and a DC voltage of 6000 V was applied.
Next, the unstretched film is heated to 95 ° C. to make it longitudinally 3.
The film was stretched 5 times to obtain a uniaxially stretched film. One surface of this film is subjected to a corona discharge treatment in an air atmosphere, and the above-mentioned water-soluble paint for forming an easily adhesive layer (water-soluble copolymerized polyester, coating agent concentration: 2.0 wt%) is applied to the treated surface by a gravure coating method. did. The coating thickness was such that the easily adhesive layer had a thickness of 0.1 μm after biaxial stretching. Subsequently, it was led to a tenter heated to 100 ° C. and stretched 3.5 times in the horizontal direction.
Heat treated at 0 ° C. for 4 seconds to have a thickness of 10 μm having an easily adhesive layer
Was obtained. Tables 1 and 3 show the composition and properties of the film. The adhesiveness, blocking resistance and solvent resistance of the film were all good.

Example 2 In the same manner as in Example 1, terephthalic acid 82 mol%, isophthalic acid 1.0 mol%, adipic acid 5.0 mol%, 5-sodium sulfoisophthalic acid 12 mol%, and the glycol component was ethylene glycol A water-soluble copolymerized polyester of 90 mol% and 10 mol% of diethylene glycol was obtained (intrinsic viscosity 0.56 dl / g).

2 g of the obtained water-soluble copolymerized polyester was put into 100 g of water, stirred and dissolved at 80 ° C. for 2 hours, cooled, and filtered with a 2 μm filter to obtain an aqueous solution of the water-soluble copolymerized polyester. The aqueous solution was almost transparent, and no filtrate was observed. 5 parts by weight of an aqueous dispersion of carnauba wax (manufactured by YAS Co., Ltd.) was added to 100 parts by weight of the solid content of the aqueous solution of the water-soluble copolymerized polyester to prepare a mixed coating agent of the water-soluble copolymerized polyester and wax. did. The coating agent was applied to a uniaxially stretched polyester film in the same manner as in Example 1 to obtain a biaxially oriented polyester film having a thickness of 10 μm and an easily adhesive layer thickness of 0.1 μm. Tables 1 and 3 show the composition and properties of the film. The adhesiveness, blocking resistance and solvent resistance of the film were all good.

Example 3 Organic particles of crosslinked acrylic / crosslinked styrene (NANOTEX, manufactured by Nippon Synthetic Rubber Co., Ltd., average particle diameter: 40 nm) were further added to the water-soluble copolymerized polyester / wax mixture coating solution of Example 2 by water solubility. Solid content of copolyester 10
Except for adding 5 parts by weight to 0 parts by weight, the thickness of the adhesive layer was 10 μm having an easily adhesive layer thickness of 0.1 μm in exactly the same manner as in Example 2.
m biaxially oriented polyester film was obtained. Tables 1 and 3 show the composition and properties of the film. Film adhesion,
Both blocking resistance and solvent resistance were good.

Comparative Example 1 83.6 parts by weight of dimethyl terephthalate, 17.4 parts by weight of dimethyl 5-sodium sulfoisophthalate, 61.0 parts by weight of ethylene glycol and 0.1 part of calcium acetate
Parts by weight and 0.03 parts by weight of antimony trioxide were added, and the mixture was subjected to a transesterification reaction according to a conventional method, and then 0.05 parts by weight of trimethyl phosphate was added. Subsequently, the temperature was gradually increased and the pressure was reduced, and finally a polycondensation reaction was carried out at 280 ° C. and 1 mmHg or less to obtain a water-soluble copolymerized polyester. The composition of the resulting water-soluble polymerized polyester was determined by NMR ( ¹³ C-N
As a result, the acid component was 88 mol% of terephthalic acid, 12 mol% of 5-sodium sulfoisophthalic acid, and the glycol component was ethylene glycol 83.
Mol% and diethylene glycol 17 mol% (intrinsic viscosity 0.55 dl / g).

2 g of the obtained water-soluble copolymerized polyester was put into 100 g of water, stirred and dissolved at 80 ° C. for 2 hours, cooled, and filtered with a 2 μm filter to obtain an aqueous solution of the water-soluble copolymerized polyester. The aqueous solution of the water-soluble copolymerized polyester was slightly cloudy, and a filtered product was observed.

On the other hand, in the same manner as in Example 1, 0.1 μm
A biaxially oriented polyester film having a thickness of 10 μm and having an easily adhesive layer was obtained. Table 2 and Table 4 show the composition and properties of the film.
It was shown to. This film had poor adhesion.

Example 4 to Example 6, Comparative Example 2 to Comparative Example 4 The water-soluble copolymerized polyester and the coating agent were laminated in the same manner as in Example 1 except that the types and amounts of the acid component and the glycol component were changed. Thus, an easily adhesive polyester film was obtained.
The compositions and properties of the films are shown in Tables 1, 2, 3, and 4. Examples 4 to 6 were within the scope of the present invention, and the film had good adhesiveness, blocking resistance, and solvent resistance.

On the other hand, in Comparative Example 2, the amount of the aliphatic dicarboxylic acid was out of the range of the present invention, and the obtained easily adhesive polyester film had good adhesion,
The solvent resistance was poor. In Comparative Example 3, the amount of diethylene glycol was out of the range of the present invention, and the blocking resistance and the solvent resistance were poor.

Further, in Comparative Example 4, the ester-forming sulfonic acid alkali metal salt compound was outside the scope of the present invention, and the obtained copolymerized polyester was poor in water solubility.

[0063]

[Table 1]

[Table 2]

[Table 3]

[Table 4]

[0064]

As described above, according to the present invention, a specific amount of 2
At least one kind of aromatic dicarboxylic acid, aliphatic dicarboxylic acid and ester-forming sulfonic acid metal salt compound, specific amount of aliphatic glycol having 2 to 8 carbon atoms or alicyclic glycol having 6 to 16 carbon atoms, diethylene glycol as glycol component Adhesive polyester obtained by laminating a coating agent consisting of a water-soluble copolymerized polyester consisting of alone or a mixture of the polyester and a higher fatty acid wax, and further a coating agent consisting of a mixture of the polyester and a higher fatty acid wax and particles This film is excellent in water solubility of water-soluble copolyester, excellent adhesiveness of the obtained easily adhesive film, blocking resistance, solvent resistance, slipperiness, etc., magnetic recording materials, various photographic materials, packaging materials, electricity Although it can be applied to insulating materials, general industrial materials, etc., it is particularly preferably used for magnetic recording materials.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-56979 (JP, A) JP-A-4-277532 (JP, A) JP-A-2-229838 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) B32B 1/00-35/00 C08J 7/04 C08G 63/00-63/698 C09D 167/00-167/08

Claims (3)

(57) [Claims] 1. An acid component comprising at least one surface of two or more aromatic dicarboxylic acids 70 on at least one surface of a polyester film.
Mol% or more, 0.01 to 8 mol% of aliphatic dicarboxylic acid and ester-forming alkali metal salt of sulfonic acid 8
25 to 25 mol%, as a glycol component, aliphatic glycol having 2 to 8 carbon atoms or 80 to 99 mol% of alicyclic glycol having 6 to 16 carbon atoms, diethylene glycol 1 to 20
An easily-adhesive polyester film comprising a water-soluble copolyester consisting of mol% laminated as an easily-adhesive layer. 2. The easily adhesive polyester film according to claim 1, wherein a higher fatty acid wax is further mixed into the easily adhesive layer. 3. The easily adhesive polyester film according to claim 1, wherein a higher fatty acid wax and particles are further added to the easily adhesive layer.