JPH11152327A - Water-soluble polyester copolymer, and film or sheet laminating it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a water-soluble copolymer which can give laminated films excellent in mutual sticking prevetiveness and adhesion to a functional layer comprising a hydrophilic resin, by selecting a copolymer wherein the dicarboxylic acid component comprises naphthalenedicarboxylic acid, a sulfonate- containing dicarboxylic acid, and an alicyclic dicarboxylic acid, and the glycol component contains an alicyclic diol. SOLUTION: The water-soluble polyester copolymer is obtained from a dicarboxylic acid component comprising (A) 20-60 mol.% naphthalenedicarboxylic acid and/or its esterifiable derivative, (B) 5-20 mol.% sulfonate-containing dicarboxylic acid and/or its esterifiable derivative, and (C) 30 mol.% or above alicyclic dicarboxylic acid and/or its esterifiable derivative (C) and a glycol component having a composition of (D) 20 mol.% or above, based on the total glycol component, alicyclic diol, and in which the sum of the mol.%, based on the total dicarboxylic acid component, component C and the mol.%, based on the total glycol component, component D is 50 mol.% or above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used as an adhesive layer between a polyester film and a functional layer made of a hydrophilic resin, and has excellent anti-adhesion properties and excellent adhesion to a functional layer made of a hydrophilic resin. The present invention relates to a polyester copolymer and films and sheets obtained by laminating the same.

[0002]

2. Description of the Related Art Polyethylene terephthalate (PET)
Or polyester film represented by polyethylene naphthalate (PEN) has mechanical strength, dimensional stability,
Because of its excellent flatness, heat resistance and optical properties, it is used as a support film in various applications.

Various functional films have been manufactured by coating or laminating functional layers such as an ink image receiving layer and a photosensitive layer on the surface of such a polyester film.

[0004] However, polyester films are
There is a disadvantage that adhesion to various functional layers, particularly functional layers made of a hydrophilic resin, is poor.

Accordingly, it is common practice to provide an adhesive layer between the polyester film and various functional layers. In particular, use of a water-soluble or water-dispersible polyester copolymer as the adhesive layer for improving the adhesiveness with the functional layer made of a hydrophilic resin, because of the work environment and the advantage that explosion-proof equipment is not required. Has been proposed.

For example, Japanese Patent Publication No. 47-40873 discloses an ester-forming sulfonic acid metal base-containing compound.
Copolymers using at least 20 mol% and at least 20 mol% of polyethylene glycol based on the total glycol component are described. In Japanese Patent Publication No. 7-119279,
Use of terephthalic acid and isophthalic acid and dicarboxylic acids and / or their ester-forming derivatives with 5 to 15 mol% of sulfonic acid salts, 10 mol% of alicyclic dicarboxylic acids and / or their ester-forming derivatives Polymers are described. However, since these copolymerized polyesters have a low glass transition temperature (Tg), when the polyester films coated with these are stored, the films are fixed to each other, and it is impossible to proceed to the next functional layer coating step. There is a problem.

Accordingly, a water-soluble or water-dispersible polyester copolymer having a high Tg and using 2,6-naphthalenedicarboxylic acid and / or an ester-forming derivative thereof as a water-soluble polyester copolymer having excellent anti-sticking properties. The union is described in JP-A-4-332756 and JP-A-6-6-1.
JP-A-16487, JP-A-8-225634, JP-T-8-508528, JP-T-9-500677
No., published in Japanese Patent Application Publication No. However, these water-soluble or water-dispersible polyester copolymers have low adhesiveness to a functional layer made of a hydrophilic resin.For example, when an ink image-receiving layer is used for the functional layer and an ink jet recording sheet is used, There is a problem that the functional layer is separated from the support film after recording on the ink image receiving layer by the aqueous inkjet printer.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide an excellent adhesion preventing property between films after application and an excellent adhesive property with a functional layer made of a hydrophilic resin. Another object of the present invention is to provide a water-soluble polyester copolymer in which a functional layer does not peel off, and a film and a sheet obtained by laminating the same.

[0009]

The object of the present invention is to provide (A) 20 to 60 mol% of naphthalenedicarboxylic acid and / or an ester-forming derivative thereof, based on the total dicarboxylic acid component, and (B) the total dicarboxylic acid component. 5 to 20 mol% of a dicarboxylic acid having a sulfonic acid salt and / or an ester-forming derivative thereof, (C) alicyclic dicarboxylic acid and alicyclic diol (based on all dicarboxylic acid components of alicyclic dicarboxylic acid) (The sum of the ratio (mol%) and the ratio (mol%) of the alicyclic diol to the total glycol component) is 50.
It can be attained by a water-soluble polyester copolymer characterized by comprising at least mol% and films and sheets obtained by laminating the same.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail. Examples of the naphthalenedicarboxylic acid and its ester-forming derivative used in the present invention include 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, dimethyl 2,6-naphthalenedicarboxylic acid, and dimethyl 2,7-naphthalenedicarboxylic acid. And the like, and 2,6-naphthalenedicarboxylic acid and dimethyl 2,6-naphthalenedicarboxylate are preferred in view of production cost. These naphthalenedicarboxylic acids and ester-forming derivatives thereof are used in an amount of 20 mol% based on the total dicarboxylic acid component from the viewpoint of preventing sticking.
It is contained above. On the other hand, if it exceeds 60 mol%, the adhesiveness to a functional layer made of a hydrophilic resin is reduced. The preferred content of naphthalenedicarboxylic acid and / or its ester-forming derivative is from 25 to 6 based on the total dicarboxylic acid component.
0 mol%.

As the dicarboxylic acid having a sulfonic acid salt and the ester-forming derivative thereof used in the present invention, those having an alkali metal salt of a sulfonic acid are particularly preferable. Examples thereof include 4-sulfoisophthalic acid and 5-sulfoisophthalic acid. Acid, sulfoterephthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid,
Alkali metal salts such as 5- [4-sulfophenoxy] isophthalic acid or its ester-forming derivative are used, but 5-sulfoisophthalic acid sodium salt or its dimethyl ester is particularly preferred. These dicarboxylic acids having a sulfonic acid salt and / or an ester-forming derivative thereof are used in consideration of the water solubility of the copolymerized polyester and the adhesiveness of the functional layer made of a hydrophilic resin when wet with respect to all dicarboxylic acid components. It is contained in the range of 5 to 20 mol%, particularly preferably 8 to 15 mol%.

When the content of the dicarboxylic acid having a sulfonic acid salt is less than 5 mol%, the polyester copolymer does not dissolve in water. On the other hand, when the content exceeds 20 mol%, the polyester copolymer is easily dissolved in water, and the adhesiveness to the functional layer made of a hydrophilic resin is reduced particularly in a water-containing state.

Examples of the alicyclic dicarboxylic acid and its ester-forming derivative include 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and 1,2-cyclohexanedicarboxylic acid.
For example, cyclohexanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 4,4′-bicyclohexyldicarboxylic acid, or an ester-forming derivative thereof is used.

Further, as the alicyclic diol, 1,4-
Cyclohexane dimethanol, 1,2-cyclohexane dimethanol, 1.3-cyclobutane dimethanol and the like can be mentioned.

These alicyclic dicarboxylic acids and alicyclic diols have a ratio (mol%) of the alicyclic dicarboxylic acid to the total dicarboxylic acid component from the viewpoint of the adhesiveness of the alicyclic dicarboxylic acid to the functional layer made of a hydrophilic resin when it contains water. And the sum of the ratio (mol%) of the alicyclic diol to the total glycol component is 50 mol% or more. If it is less than 50 mol%, the adhesiveness between the water-soluble polyester copolymer and the functional layer made of a hydrophilic resin will be reduced.

As other dicarboxylic acids and their ester-forming derivatives, terephthalic acid, isophthalic acid, 4,4'-biphenylenedicarboxylic acid, adipic acid and the like, or their ester-forming derivatives may be used. Other glycol components include ethylene glycol, 1,4-butanediol, neopentyl glycol, 3,3-dimethylolheptane, diethylene glycol, triethylene glycol, polyethylene glycol, and the like, with ethylene glycol being preferred.

As the polymerization method of the copolymerized polyester in the present invention, various ordinary methods can be used. For example,
After transesterification of dimethyl ester of dicarboxylic acid and glycol and distilling off methanol, a method of performing polycondensation under gradually reducing pressure and high vacuum, or performing esterification reaction of dicarboxylic acid and glycol to produce After distilling the water that has been distilled off, gradually reduce the pressure and perform polycondensation under high vacuum, or when using dimethyl ester of dicarboxylic acid and dicarboxylic acid as raw materials, dimethyl ester of dicarboxylic acid and ester of glycol After the exchange reaction, there is a method in which a dicarboxylic acid is further added to perform an esterification reaction, and then polycondensation is performed under high vacuum.

As a transesterification catalyst, manganese acetate,
Known ones such as calcium acetate, zinc acetate and the like and polycondensation catalysts such as antimony trioxide, germanium oxide, dibutyltin oxide and titanium tetrabutoxide can be used. As a stabilizer, a phosphorus compound such as trimethyl phosphate or triphenyl phosphate, Irganox 101
A hindered phenolic compound such as 0 may be used. However, various conditions such as a polymerization method, a catalyst, and a stabilizer are not limited to those described above.

Although the polyester copolymer of the present invention has water solubility, the term "water solubility" as described in the present invention is not strictly physicochemically, but also includes those which dissolve or finely disperse in water. The copolymerized polyester of the present invention preferably has an intrinsic viscosity of 0.2 g / dl or more. If the intrinsic viscosity is too low, it will be difficult to obtain sufficient adhesiveness.

The substrate on which the copolymer is provided in the film or sheet of the present invention includes a film or sheet made of a resin such as polyester, and paper. Among them, films and sheets made of saturated polyester such as polyethylene terephthalate and polyethylene naphthalate, and paper are preferable.

As a method for producing the film or sheet of the present invention, any method can be used as long as the water-soluble polyester copolymer can be laminated on the above-mentioned substrate, and the following method is particularly preferably used. . That is, this is a method in which the water-soluble polyester copolymer of the present invention is dissolved in hot water to form an aqueous solution, and then coated and dried on a substrate using a bar coater or a gravure coater.

[0022]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. The measurement and evaluation methods are described below.

(1) Intrinsic Viscosity of Polyester Copolymer The polyester copolymer is phenol / 1,1,2,2-
It was dissolved in a mixture of tetrachloroethane = 60/40 (weight ratio) and measured at 20 ° C.

(2) Glass Transition Temperature of Polyester Copolymer After melting the polyester copolymer at 200 ° C. with DSC-7 manufactured by Perkin Elmer, the temperature was reduced to 0 ° C. at a rate of 300 ° C. per minute.
Cool rapidly to ° C. Thereafter, the glass transition temperature when the temperature was raised at a rate of 10 ° C. per minute was measured.

(3) Adhesiveness After cross-cutting the surface of the polyester film provided with the functional layer made of a hydrophilic resin, the peeling condition of the functional layer made of the hydrophilic resin (peeling area) when performing a cellophane tape peeling test ) Was visually observed and judged based on the criteria shown in Table 1 below.

[0026]

[Table 1]

(4) Anti-sticking property (anti-blocking property of the support film) The easy-adhesive resin layer of the support film and the surface of the film not provided with the easy-adhesive layer and the functional layer made of a hydrophilic resin are overlapped, 40 ° C, humidity 80% RH, load 10kg / c
In m ² for 20 hours press treatment, ASTM D189
In accordance with the method of measuring and quantifying the degree of blocking between plastic films determined in 3, the anti-sticking property was determined from the load applied when the pressed film surface was peeled off. The criteria are as shown in Table 2 below.

[0028]

[Table 2]

EXAMPLE 1 Dimethyl 2,6-naphthalenedicarboxylate 128.27
Parts by weight, 51.86 parts by weight of dimethyl 5-sulfoisophthalate, 50.49 parts by weight of 1,4-cyclohexanedimethanol, 95.62 parts by weight of ethylene glycol, 0.1621 parts by weight of calcium acetate monohydrate, acetic acid After transesterification of 0.0540 parts by weight of manganese tetrahydrate under a nitrogen stream at 170 to 230 ° C. while distilling off methanol, trimethyl phosphate 0.129 was added.
0 parts by weight, antimony trioxide 0.12 as polycondensation catalyst
Then, 00 parts by weight and 80.38 parts by weight of 1,4-cyclohexanedicarboxylic acid were added, and at a reaction temperature of 230 to 280 ° C., almost a theoretical amount of water was distilled off to carry out esterification. Thereafter, the pressure inside the reaction system was further reduced and the temperature was raised.
Polycondensation was performed for 1 hour at mmHg.

When the obtained copolymer was analyzed, the intrinsic viscosity was 0.25 dl / g and the glass transition temperature (Tg) was 7
2.3 ° C. The polyester copolymer was stirred in hot water at 95 ° C. for 2 hours to form a 15% by weight aqueous solution, and then a slightly cloudy 8% by weight aqueous solution obtained by diluting with water was used as a coating liquid.

This coating solution was applied on both sides of a 50 μm-thick polyethylene terephthalate film with a bar coater so that the coating thickness after drying was about 0.1 μm, thereby providing an easily adhesive resin layer. A support film was obtained.

Next, the following coating solution was applied to one surface of the support film by a bar coater so as to have a dry thickness of 7 μm to provide a functional layer made of a hydrophilic resin. As the coating liquid, a water / alcohol mixed solvent solution containing 8% by weight of polyvinyl butyral resin (“KX-1” manufactured by Sekisui Chemical Co., Ltd.) was used as a main component, and a coating liquid containing colloidal silica was used.

The above-mentioned evaluation was performed using this film. Table 3 shows the evaluation results.

Examples 2 to 7 Examples 2 to 7 were repeated in the same manner as in Example 1 except that the composition of the polyester copolymer was changed as shown in Tables 3 and 4.
7 was performed. Tables 3 and 4 show the evaluation results.

Comparative Examples 1 to 5 Comparative Examples 1 to 8 were carried out in the same manner as in Example 1 except that the composition of the polyester copolymer was changed as shown in Table 1. Tables 5 and 6 show the evaluation results.

[0036]

[Table 3]

[0037]

[Table 4]

[0038]

[Table 5]

[0039]

[Table 6]

As is apparent from Tables 3 to 6, 2,6-
In Comparative Example 1 in which dimethyl naphthalenedicarboxylate was not used, it was difficult to satisfy both the properties of adhesiveness and anti-sticking properties. In Comparative Example 2 in which the molar ratio of dimethyl 5-sulfoisophthalate Na salt was reduced, the copolymerized polyester did not dissolve in water. Comparative Example 3 in which the molar ratio of dimethyl 5-sulfoisophthalic acid Na salt exceeds 20 mol%, Comparative Example 4 in which the molar ratio of dimethyl 2,6-naphthalenedicarboxylate exceeds 60 mol%, and 1,4-cyclohexanedicarboxylic acid In Comparative Examples 6 to 8 in which the sum of the molar ratios of 1,4-cyclohexanedimethanol is less than 50 mol%, the adhesiveness cannot be satisfied. Furthermore, in Comparative Example 5 in which the amount of dimethyl 2,6-naphthalenedicarboxylate is less than 20 mol%, the adhesion is good, but the anti-sticking property is deteriorated.

In contrast to the comparative examples described above, the copolymerized polyester of the present invention was satisfactory in both adhesiveness and fixability.

[0042]

According to the present invention, the adhesion between the films after application and the adhesion to the functional layer made of a hydrophilic resin are excellent, and the functional layer made of a hydrophilic resin is not peeled off. A water-soluble polyester copolymer having excellent properties as an adhesive layer with a functional layer made of a hydrophilic resin such as an ink jet recording sheet is supplied.

Claims (3)

[Claims] (1) 20 to 60 mol% of naphthalenedicarboxylic acid and / or an ester-forming derivative thereof with respect to (A) all dicarboxylic acid components, and (B) a sulfonic acid salt with respect to (B) all dicarboxylic acid components. Dicarboxylic acid and / or
Or 5 to 20 mol% of the ester-forming derivative thereof,
(C) an alicyclic dicarboxylic acid and an alicyclic diol (sum of the ratio (mol%) of the alicyclic dicarboxylic acid to the total dicarboxylic acid component and the ratio (mol%) of the alicyclic diol to the total glycol component) are 50 A water-soluble polyester copolymer comprising at least mol%. 2. An alicyclic dicarboxylic acid and / or an ester-forming derivative thereof is added to 30 parts of the total dicarboxylic acid component.
2. The water-soluble polyester copolymer according to claim 1, wherein the alicyclic diol is contained in an amount of 20 mol% or more based on the total glycol component. 3. Films and sheets obtained by laminating the water-soluble polyester copolymer according to claim 1.