JPH08176284A - Water-soluble polyester and method for producing the same - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a water-soluble polyester capable of forming an easily-adhesive coating film with less electrostatic charge and a method for producing the same. [Structure] An ion dissociative group-containing dicarboxylic acid component and / or an ion dissociative group-containing glycol component is contained in the molecular main chain of polyester in an amount of 51 mol% or more based on all acid components.
And a water-soluble polyester characterized in that the polyester is produced at a polymerization temperature of 180 ° C. or higher and lower than 240 ° C., and an intrinsic viscosity measured at 35 ° C. in orthochlorophenol is 0.25 or higher, and a polymerization temperature of 180 ° C. or higher 240
A method for producing the above water-soluble polyester, which comprises carrying out a polymerization reaction at a temperature of less than ° C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-soluble polyester and a method for producing the same, and more particularly to a water-soluble polyester capable of forming an easily adhesive coating film (easy adhesive layer) with low charge and a method for producing the same. Further, the present invention relates to a low-charge and easily-adhesive polyester film coated with the water-soluble polyester, which is useful for packaging materials, magnetic cards, magnetic tapes, magnetic disks, printing materials and the like.

[0002]

2. Description of the Related Art Thermoplastic polyesters such as polyethylene terephthalate or its copolymers, polyethylene naphthalate or its copolymers, or blends of these with a small proportion of other resins are melt extruded, and after biaxial stretching, The fixed polyester film has excellent mechanical strength, heat resistance, chemical resistance and the like, and is used in various fields in industry. However, its surface is highly oriented and therefore has the drawback of poor ink and magnetic paint receptivity, for example.

As a method of increasing the receptivity of the surface of the polyester film, there is a method of previously forming a primer layer (undercoat layer) of a synthetic resin on the surface of the film and forming a thin surface layer different from the base film. The formation of the primer layer is carried out by using a synthetic resin solution in an organic solvent or an aqueous solution (aqueous solution,
It is carried out by using a water dispersion) and applying it to the film surface.

As the aqueous resin liquid for forming the primer layer, an aqueous liquid of polyester polymer, an aqueous liquid of acrylic polymer and the like are known. Particularly, regarding an aqueous liquid of a polyester polymer, for example, Japanese Patent Publication No.
Many proposals have been made such as -5476 and JP-A-60-248232. However, the polyester film coated with the primer layer using the polyester-based polymer disclosed in these examples has a large electrostatic charge, and when rewinding, electrification is accumulated, and an explosive fire may occur due to discharge of the accumulated electric charge. Further, there is a drawback that dust and the like are adsorbed by the accumulated charges and cause dropout in the magnetic recording medium.

[0005]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention The inventors of the present invention have begun investigations to solve the above-mentioned drawbacks of the prior art and develop a primer layer having less charge and excellent adhesiveness. Based on the idea that the presence of a large amount of groups imparts ionic conductivity to the polymer, we attempted to develop a polyester having a large amount of ion dissociative groups.

Japanese Patent Publication No. 62-21381 discloses a polyester containing a large amount of ion dissociative groups. That is, in the publication, 11 to 100 mol% of the total acid component is composed of a sulfonic acid metal group-containing aromatic dicarboxylic acid, and the glycol component is 10 to 100 mol% of an aliphatic glycol and / or an alicyclic glycol and bisphenol A. 90 to 0 mol% of ethylene oxide or propylene oxide adduct, having a molecular weight of 2,500
An aqueous solution of a polyester resin having a softening point of 0 to 30,000 and a softening point of 40 to 200 ° C has been proposed. However, as a specific example of this, as Production Example 1, a polyester obtained by copolymerizing 20 mol% of 5-sodium sulfoisophthalic acid component was synthesized by a transesterification reaction, a glycol of dicarboxylic acid containing zinc acetate and antimony trioxide. While increasing the temperature of the ester and its low polymer (oligomer) from 240 ° C to 270 ° C, the degree of vacuum is 10 mmHg.
It is disclosed that a polycondensation reaction is carried out while increasing to 0.2 mmHg, and that a polyester obtained by copolymerizing a 5-sodium sulfoisophthalic acid component at a maximum of 50 mol% is produced by the same method. In other words, this publication does not show a concrete production example of a polyester obtained by copolymerizing a 5-sodium sulfoisophthalic acid component in an amount of more than 50 mol%.

Therefore, the present inventors tried to polymerize the polymer according to Production Example 1 of JP-B-62-21381 except that the content of 5-sodium sulfoisophthalic acid component was increased to 80 mol%. It foamed more violently and solidified in a foamy state, and the polymerization reaction did not proceed.
That is, it was found that the method described in Japanese Patent Publication No. Sho 62-21381 cannot polymerize a copolymer containing an ionic dissociative group component at a high concentration.

As a disclosure of another example of the copolymer containing an ion-dissociative group component, JP-A-57-8 is disclosed.
No. 3,451, JP-A No. 61-85436, and the like, all of them are cases where the copolymerization ratio of the ion dissociative group component is less than 50 mol%. For example, in Example 1 of JP-A-57-83451, the glycol ester of dicarboxylic acid containing 10 mol% of 5-sodium sulfoisophthalic acid component was heated from 240 ° C. to 280 ° C. using antimony trioxide as a polymerization catalyst. An example is shown in which the polycondensation reaction is performed while warming and gradually increasing the degree of vacuum from atmospheric pressure to 0.5 mmHg.

Therefore, it has been found that a polyester containing an ionic dissociative group component in a proportion exceeding 50 mol% with respect to the total acid component cannot be produced by the conventional method, and a new polymerization method is required.

As a result of further diligent study on this problem, the present inventors have found that by suppressing the polymerization temperature to a low level,
It is possible to polymerize a polyester obtained by polymerizing an ion-dissociative group component in a high concentration of more than 50 mol%, and particularly coating a polyester aqueous solution by setting the ratio of the ion-dissociative group component to 80 mol% or more based on the total acid component. It was found that the film exhibits more sufficient electrostatic properties.

An object of the present invention is to provide a water-soluble polyester capable of forming an easily-adhesive polyester film having less charge and a method for producing the same, and a low-charge easily-adhesive polyester film coated with the water-soluble polyester. To provide.

[0012]

The first object of the present invention is, according to the present invention, that all of the ion-dissociable group-containing dicarboxylic acid component and / or the ion-dissociable group-containing glycol component is contained in the molecular backbone of the polyester. It has 51 mol% or more with respect to the acid component, and the polyester has a polymerization temperature of 180 ° C or higher and 24
Manufactured below 0 ° C, 35 ° C in orthochlorophenol
It is achieved by a water-soluble polyester characterized by having an intrinsic viscosity of 0.25 or more.

In the present invention, the water-soluble polyester is a polyester having 51 mol% or more of an ion-dissociative group-containing dicarboxylic acid component and / or an ion-dissociative group-containing glycol component in the polymer molecule main chain.
When this amount is 50 mol% or less (based on all acid components), sufficient electrostatic performance is not exhibited. A preferred amount is 80 mol% or more (based on the total acid content). The upper limit of this amount is 100 mol% (based on all acid components) without limitation. The ionic dissociative group-containing dicarboxylic acid component and the ionic dissociative group-containing glycol component can be used in combination, but in this case, the total amount of both is 51 mol% or more, preferably 80 mol, based on the total acid component. % Or more.

In the present invention, examples of the ion dissociative group include a sulfonate group, an ammonium group, a carboxylate group and the like, and among these, the sulfonate group is preferable.

Examples of the dicarboxylic acid containing an ion dissociative group include 5-sodium sulfoisophthalic acid, 5-lithium sulfoisophthalic acid, sulfoaromatic dicarboxylic acid such as 5-phosphonium sulfoisophthalic acid, 5-sodium sulfosuccinic acid, 5 Examples thereof include sulfoaliphatic dicarboxylic acids such as lithium sulfosuccinic acid and 5-phosphonium sulfosuccinic acid. Among these, 5-sodium sulfoisophthalic acid and 5-lithium sulfoisophthalic acid are preferable.

As the ionic dissociative group-containing glycol,
Formula 1 below

[0017]

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(Wherein X ₁ and X ₂ are hydrogen, methyl or alkyl having 2 to 5 carbon atoms, and Y is --CH _2- , --C
(CH ₃ ) ₂ —, —SO ₂ — or a direct bond, M is an alkali metal, an alkaline earth metal or phosphonium, and 1 + m is a number of 2 to 50. ) A lower alkylene oxide adduct of sulfobisphenol represented by
Formula 2 below

[0019]

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Preferable examples are the lower alkylene oxide adducts of sulfohydroquinone represented by (wherein X ₁ , X ₂ , M, l and m are the same as those in the above formula 1).

In the present invention, an acid component or a glycol component containing no ion dissociative group can be used.
The acid component containing no ion dissociative group includes isophthalic acid, 1,3-cyclohexanedicarboxylic acid, 1,
4-cyclohexanedicarboxylic acid, phenylindanedicarboxylic acid, oxalic acid, malonic acid, glutanoic acid, adipic acid, azelaic acid, sebacic acid, maleic acid, itaconic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid,
Preferable examples include 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid and 4,4′-diphenyldicarboxylic acid, and examples of the glycol component containing no ion dissociative group include neopentyl glycol, 1,
Preferable examples include 3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, alkylene oxide adducts of bisphenol compounds, alkylene glycols having 2 to 10 carbon atoms, and 2,5-naphthalenediol. These may be used alone, or may be used in combination with several kinds of dicarboxylic acids and / or glycols.

In the present invention, the water-soluble polyester has a high proportion of the ion dissociative-containing component (acid component, glycol component) in the molecular main chain as described above, but the polyester has a polymerization temperature of 180 ° C. or higher and lower than 240 ° C. It needs to be manufactured by carrying out a polymerization reaction. Preferred polymerization temperature is 1
The temperature is 98 ° C or higher and lower than 240 ° C, and more preferable polymerization temperature is 198 ° C or higher and 220 ° C or lower. When the polymerization temperature is 240 ° C. or higher, the glycol ester of dicarboxylic acid and / or the oligomer thereof used in the polymerization reaction foams more violently than in the initial stage of the polymerization reaction, and remains as bubbles to prevent the polymerization reaction from proceeding.

It is preferable that the above-mentioned polymerization reaction is performed at least after the reaction under the conditions of a vacuum degree of 0.05 mmHg or more and 100 mmHg or less.

The glycol ester of dicarboxylic acid and / or its oligomer (low molecular weight polymer) used (used) in the polymerization reaction may be produced by a conventional method such as a direct esterification method or a transesterification method. The direct esterification method is a method of producing a glycol ester of dicarboxylic acid and / or an oligomer thereof by subjecting a dicarboxylic acid and a glycol to an esterification reaction. The transesterification method is a method for producing a glycol ester of dicarboxylic acid and / or an oligomer by transesterifying an ester-forming derivative of dicarboxylic acid (for example, a lower alkyl ester such as dimethyl ester) and glycol.

At that time, it is preferable to use a reaction catalyst, and other additives such as a stabilizer and an antioxidant can be added. As the polymerization reaction catalyst, titanium compounds such as titanium tetraalkoxide such as tetrabutoxy titanium, titanium acetate, etc. can be preferably used.

The water-soluble polyester thus obtained has an intrinsic viscosity of 0.25 or more measured at 35 ° C. in orthochlorophenol. When the intrinsic viscosity is less than 0.25, the physical properties become poor when the easily adhesive primer layer is formed, which is not preferable.

The water-soluble polyester in the present invention is easily soluble in warm water. Therefore, an aqueous polyester solution to be applied to a polyester film can be easily produced by dissolving the water-soluble polymer in warm water.

If the polymer concentration in the aqueous solution is too high, the viscosity of the aqueous solution increases and it becomes difficult to apply, so it is preferable to set it to 40% by weight or less. On the other hand, if the polymer concentration is too low, the coating amount of the aqueous solution required to form a primer layer having a predetermined thickness increases, so 0.5% by weight or more is preferable, and 3% by weight is more preferable.
That is all.

The polyester aqueous solution thus obtained is
By coating one or both sides of a polyester film described below and drying, the film can be imparted with low charge and easy adhesive properties.

The aqueous polyester solution can be used by adding a necessary amount of a surface active agent such as an anionic surface active agent or a nonionic surface active agent at the time of coating. As an effective surfactant, the surface tension of the polyester aqueous solution is 50d.
Many known surfactants can be used as long as they can be lowered to yne / cm or less and accelerate the wetting of the polyester film. Examples thereof include polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, glycerin fatty acid ester, fatty acid metal soap, alkyl sulfate, alkyl sulfonate, alkyl sulfosuccinate, quaternary ammonium chloride, alkyl amine. Hydrochloride, sodium dodecylbenzene sulfonate, etc. may be mentioned.

If necessary, additives such as an antistatic agent, a filler, an ultraviolet absorber, a lubricant and a coloring agent may be added to the polyester aqueous solution.

Preferred examples of the polyester film in the present invention include a film made of polyethylene terephthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, or a copolymer obtained by copolymerizing these with other copolymerization components. The polyester film may be an unstretched film, a uniaxially stretched film or a biaxially stretched film, but a stretched film is preferred.

The step of applying the aqueous polyester solution to the polyester film can be arbitrarily selected. Preferably, after applying an aqueous polyester solution to an unstretched film or a uniaxially stretched film, it is dried by heating and then further stretched,
Apply to a biaxially stretched film and dry. Of these, it is particularly preferable to apply to this uniaxially stretched film.

The coating can be carried out by a conventional method, for example, kiss coating, reverse coating, gravure coating, die coating and the like. The coating amount is 0.01-5 μm (dry)
Is preferable, and more preferably 0.01 to 2 μm (dr
y), most preferably 0.01 to 0.3 μm (dr
y).

The easily-adhesive polyester film thus obtained has a high adhesive force and a low electrostatic charge, and thus is useful for, for example, magnetic cards, magnetic tapes, magnetic disks, printing materials, graphic materials, photosensitive materials and the like.

[0036]

EXAMPLES The present invention will be described in more detail with reference to examples. In addition, "part" in an Example means a weight part.
Each characteristic value was measured by the following method.

(1) Adhesiveness A (primer-coated) polyester film was coated with the following magnetic paint under predetermined conditions, and Scotch tape No. 600 (manufactured by Three M Co.) width 19.4 m.
m and a length of 8 cm are adhered so that air bubbles are not required, and JIS. C2701 (1975) with a manual load roll leveling 5 cm between the laminated layers using a Toyo Baldwin Tensilon UM-II head speed of 300
This sample was T-peeled at mm / min, the peel strength at this time was determined, and this was divided by the tape width to determine g / cm. In the T-type peeling, the tape side of the laminate is faced down and the distance between the take-up chucks is set to 5 cm.

[Preparation of magnetic paint for evaluation] Nitrocellulose RS1 / 2 (Flakes containing 25% isopropanol: manufactured by Daicel Co., Ltd.) was dissolved in a paint lacquer thinner to prepare a 40 wt% solution. 9 parts, subsequently 32.5 parts of polyester resin (Desmophen # 1700: manufactured by Bayer), and 26.0 parts of chromium dioxide magnetic powder.
Parts, soybean oil fatty acid (Resion P:
Riken Vitamin Co., Ltd., a cationic activator (Cation AB: manufactured by NOF CORPORATION), and squalene (shark liver oil) are partially charged into 0.5 part and 0.8 part ball mills, respectively. 282 parts of a mixed solution of methyl ethyl ketone / cyclohexanone / toluene = 3/4/3 (weight ratio) is further mixed and sufficiently pulverized to form a mother liquor paint (45 wt%).
To prepare. To 50 parts of this mother liquor, an addition reaction product of trimethylolpropane and tolulane diisocyanate (Coronate L: manufactured by Nippon Polyurethane Industry Co., Ltd.) 48
Parts and 6.25 parts of butyl acetate were added to a final weight of 42.75.
Obtain wt% magnetic paint for evaluation.

(2) Chargeability: 2 polyester films (treated with a primer coating)
Ionized air blower (Model 1 manufactured by Hugle Electronics Co., Ltd.) cut into a size of 10 cm x 10 cm
After removing the charge in 20), the amount of charge after rubbing 5 times with a chromium-plated iron roll (diameter: 3 cm) is measured using a static electricity measuring device (Stachilon-TL manufactured by Shishido Electrostatic Co., Ltd.).

[Example 1] <Production of water-soluble polyester> Bishydroxyethyl 5
-Put 100 parts of sodium sulfoisophthalate in an autoclave and use tetrabutoxytitanium as a catalyst 0.0
After adding 7 parts, the temperature was gradually raised to 200 ° C., the pressure inside the system was reduced to 20 mmHg, and the polycondensation reaction was carried out for 1 hour to obtain an intrinsic viscosity ([η]: measured in orthochlorophenol at 35 ° C.) 0 A polyester of 0.30 was obtained. The composition of the polyester is shown in Table 1. <Preparation of Polyester Aqueous Solution> 20 parts of this polyester was added to 400 parts of water and refluxed for 2 hours to obtain a colorless and transparent aqueous solution.

Further, 20 parts of a nonionic surfactant: polyoxyethylene nonylphenyl ether (HLB = 12.8) was added to 800 parts of this polyester aqueous solution to prepare a coating solution. <Production of easily-adhesive polyester film> o at 35 ℃
Intrinsic viscosity ([η]) measured in chlorophenol 0.
65 of polyethylene terephthalate was melt extruded to obtain an unstretched film having a thickness of 158 μm, which was then stretched 3.5 times in the machine axis direction, and the coating solution prepared above was applied to one side of the uniaxially stretched film. Then, the film was stretched in the transverse direction at 105 ° C. to 3.9 times and heat-treated at 200 ° C. for 4.2 seconds to give an average coating amount of 20 mg / m ² and a thickness of 12.2 μ.
A biaxially stretched primer-coated polyester film of m was obtained. The adhesiveness and chargeability of the treated surface of this film were measured. Table 1 shows the results.

Example 2 The procedure of Example 1 was repeated except that the polymerization temperature was changed to 220 ° C., and [η] 0.28 in Table 1 was used.
A water-soluble polyester having the composition shown in was obtained. Then, an aqueous polyester solution and a coating solution were prepared in the same manner as in Example 1 except that this water-soluble polyester was used.

Furthermore, Example 1 was repeated except that this coating solution was used.
A biaxially stretched primer-coated polyester film was obtained in the same manner as above. The adhesiveness and chargeability of the treated surface of this film were measured. The results are summarized in Table 1.

[Examples 3 and 4] Bishydroxyethyl 5
-A copolymerized polyester having the composition shown in Table 1 was obtained in the same manner as in Example 1 except that a part of sodium sulfoisophthalate was changed to bishydroxyethyl terephthalate. Then, except using this copolyester,
A polyester aqueous solution and a coating solution were prepared in the same manner as in Example 1.

Further, Example 1 was repeated except that this coating solution was used.
A biaxially stretched primer-coated polyester film was obtained in the same manner as above. The adhesiveness and chargeability of the treated surface of this film were measured. The results are summarized in Table 1.

[Example 5] Dimethyl terephthalate 100
Parts, 32 parts of ethylene glycol and 155 parts of sodium sulfohydroquinone ethylene oxide adduct having the structure of the following formula 3 were charged in a transesterification reactor, and 0.07 part of tetrabutoxytitanium was added thereto and the temperature was raised under a nitrogen atmosphere. The temperature was controlled to 200 ° C. and heating was performed to distill off the produced methanol to carry out a transesterification reaction.

[0047]

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Next, Irganox 1 was added to the reaction system.
After adding 0.6 parts of 010 (manufactured by Ciba Geigy), the temperature is gradually raised to 200 ° C., and the inside of the system is 20 mmHg.
Intrinsic viscosity ([η])
0.45 copolyester was obtained. The composition of this copolyester is shown in Table 1.

Then, a polyester aqueous solution is prepared in the same manner as in Example 1 except that this copolymerized polyester is used.
Furthermore, a coating solution was prepared.

A biaxially stretched primer-coated polyester film was obtained in the same manner as in Example 1 except that this coating solution was used. The adhesiveness and chargeability of the treated surface of this film were measured. The results are summarized in Table 1.

Example 6 A biaxially stretched primer-coated polyester film was obtained in the same manner as in Example 1 except that the coating solution of Example 2 was used and the coating solution was coated on both sides. The adhesiveness and chargeability of each side of this film were measured. The results are summarized in Table 1.

Example 7 The procedure of Example 1 was repeated except that after preparing the coating liquid of Example 1, 0.5 wt% of spherical silica having an average particle size of 0.1 μm was added to the polymer. A stretched primer-coated polyester film was obtained.
The adhesiveness and chargeability of this film were measured. The results are summarized in Table 1.

Comparative Example 1 100 parts of bishydroxyethyl 5-sodium sulfoisophthalate was placed in an autoclave, 0.02 part of zinc acetate and 0.02 part of antimony trioxide were added as a catalyst, and the reaction was carried out at 270 ° C. and 10 mmHg. However, the reaction did not proceed as soon as it solidified in a foamy state. When it was left for 30 minutes in this state and then taken out, it was in the form of a free-flowing powder and was not polymerized at all.

[Comparative Example 2] A copolyester having the composition shown in Table 1 was obtained in the same manner as in Example 1 except that 50% of bishydroxyethyl 5-sodium sulfoisophthalate was changed to bishydroxyethyl terephthalate.
Next, the same procedure as in Example 1 was carried out except that this copolymerized polyester was used to prepare an aqueous polyester solution and further a coating solution.

Further, Example 1 was repeated except that this coating solution was used.
A biaxially stretched primer-coated polyester film was obtained in the same manner as in. The adhesiveness and chargeability of the treated surface of this film were measured. The chargeability was insufficient. The results are summarized in Table 1.

[Comparative Example 3] Table 1 shows the characteristics of the biaxially oriented polyester film obtained in Example 1 without coating. The adhesive strength was low and it was not practically satisfactory.

[0057]

[Table 1]

[0058]

According to the present invention, it is possible to provide a water-soluble polyester capable of forming an easily-adhesive coating film (primer layer) with less charge and a method for producing the same. Furthermore, an easily adhesive polyester film coated with the aqueous polyester solution can be provided.

[Procedure amendment]

[Submission date] January 19, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 3

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 4

[Correction method] Change

[Correction content]

Claims (6)

[Claims] 1. A polyester main chain having an ion-dissociative group-containing dicarboxylic acid component and / or an ion-dissociative group-containing glycol component in an amount of 51 mol% or more based on the total acid component, and the polyester having a polymerization temperature of 180. ℃ or more 240
A water-soluble polyester produced at a temperature of less than 0 ° C and having an intrinsic viscosity of 0.25 or more measured at 35 ° C in orthochlorophenol. 2. The water-soluble polyester according to claim 1, wherein the ion dissociative group is a sulfonate group. 3. The ion-dissociative group-containing dicarboxylic acid is a sulfonate group-containing aromatic dicarboxylic acid, and the ion-dissociative group-containing glycol is a lower alkylene oxide adduct of sulfobisphenol or a lower alkylene oxide adduct of sulfohydroquinone. The water-soluble polyester film according to claim 1 or 2. 4. A polymerization temperature of a glycol ester of a dicarboxylic acid and / or an oligomer thereof containing 51 mol% or more of an ion-dissociative group-containing dicarboxylic acid component and / or an ion-dissociative group-containing glycol component with respect to the total acid component. C. or more and less than 240.degree. C. and at least the latter stage of the reaction is subjected to polycondensation under conditions of a vacuum degree of 0.05 mmHg or more and 100 mmHg or less to obtain a polyester having an intrinsic viscosity of 0.25 or more measured at 35.degree. C. in orthochlorophenol. A method for producing a water-soluble polyester. 5. An aqueous polyester solution for film coating, which is obtained by dissolving the water-soluble polyester according to claim 1 in water. 6. A low-charge, easily-adhesive polyester film obtained by coating the polyester aqueous solution according to claim 5 on at least one surface of the polyester film and drying it.