JP2727623B2 - Copolyester composition - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a copolymerized polyester composition, and more particularly, to the dispersibility of an antistatic agent used for forming a film body of an antistatic polyester film. The present invention relates to a copolyester composition having good heat resistance. Here, the film body of the polyester film refers to the film itself, and does not include a coating layer or the like provided on the film.

[Prior art] Polyester, especially polyethylene terephthalate,
Due to its excellent physical and chemical properties, it is widely used as fibers, films and other molded products. However, polyester has a disadvantage that it is easily charged, which causes various troubles. For example, when processing into a film, troubles such as winding around a roll in a film forming process, electric shock to an operator, contamination of a film surface due to suction of dust and dust, poor printing, and entanglement between films occur.

For this reason, research on imparting antistatic properties to polyester has been conducted. For example, it has been proposed to blend a polyalkylene glycol and a metal sulfonate derivative (for example, JP-A-52-47071, JP-A-52-470).
No. 72). However, when polyalkylene glycol is blended, the resistance to oxidation deterioration of the polyester is reduced, and when polyalkylene glycol is not used, the dispersibility of the sulfonic acid metal base derivative in the polyester is deteriorated.

[Problems to be Solved by the Invention] An object of the present invention is to solve the above-mentioned drawbacks of the prior art, and is a copolymer polyester excellent in antistatic properties, excellent in antistatic agent dispersion and excellent in heat resistance. Composition.

[Means for Solving the Problems] An object of the present invention is to provide a copolymerized polyester composition used for forming a film body of a polyester film having antistatic properties, wherein at least 70 mol% of all acid components are terephthalic acid. Wherein the copolyester 10 is 0.05 to 10 mol% of a dicarboxylic acid having a sulfonic acid metal base.
This is achieved by a copolymerized polyester composition comprising, as an antistatic agent, 0.05 to 10 parts by weight of a metal salt of an organic sulfonic acid represented by the following general formula (I) in 0 parts by weight.

_{(R-SO 3) nM (} I) [ wherein, R alkyl group having 6 or more carbon atoms, an aryl group or alkylaryl group, M represents an alkali metal or alkaline earth metal. n is 1 when M is an alkali metal, and 2 when M is an alkaline earth metal. In the present invention, terephthalic acid accounts for at least 70 mol% of all the acid components of the copolymerized polyester. It is more preferably at least 80 mol%. Terephthalic acid is the total acid component
If the amount is less than 70 mol%, the mechanical strength and the elastic modulus decrease, which is not preferable.

In the present invention, it is necessary that 0.05 to 10 mol% of all the acid components of the copolymerized polyester is a dicarboxylic acid having a sulfonic acid metal base. A more preferred amount of the dicarboxylic acid having a sulfonic acid metal base is 0.05 to 7 mol% of the total acid component. If the amount is less than 0.05 mol%, the dispersibility of the metal salt of the organic sulfonic acid represented by the formula (I), which is an antistatic agent, decreases, which is not preferable. On the other hand, if it exceeds 10 mol%, the effect on the dispersibility of the antistatic agent no longer reaches saturation, and on the contrary, problems such as a decrease in mechanical strength are not preferred.

Specific examples of the dicarboxylic acid having a sulfonic acid metal base of the present invention include 5-sodium sulfoisophthalic acid, 2-sodium sulfoterephthalic acid, 4-sodium sulfophthalic acid, and 4-sodium sulfo-2,6-naphthalene. Dicarboxylic acids and their sodium to other metals (lithium, potassium, magnesium, calcium)
Embedded image A particularly preferred compound is 5-sodium sulfoisophthalic acid.

Further, in the copolymerized polyester of the present invention, as the glycol component, ethylene glycol, propylene glycol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, cycloxan dimethanol, and the like can be selected. Is preferred.

In the copolyester of the present invention, other acid components and glycol components can be further copolymerized as long as the ratio is small as long as the antistatic property and mechanical properties are not impaired.

The metal salt of an organic sulfonic acid in the present invention is a compound represented by the general formula (I).

_{(R-SO 3) nM (} I) [ wherein, R alkyl group having 6 or more carbon atoms, an aryl group or alkylaryl group, M represents an alkali metal or alkaline earth metal. n is 1 when M is an alkali metal, and 2 when M is an alkaline earth metal. Specifically, sodium dodecylsulfonate, sodium stearylsulfonate, sodium octylbenzenesulfonate, sodium dodecylbenzenesulfonate, sodium stearylbenzenesulfonate,
And sodium dodecylnaphthalenesulfonate and compounds obtained by substituting these sodiums with other metals (lithium, potassium, magnesium, calcium). Preferred compounds are the sodium, lithium and potassium salts of alkylarylsulfonic acids such as octylbenzenesulfonic acid, dodecylbenzenesulfonic acid, stearylbenzenesulfonic acid and dodecylnaphthalenesulfonic acid. A particularly preferred compound is sodium dodecylbenzenesulfonate.

The content of the metal salt of the organic sulfonic acid represented by the formula (I) is 0.0 to 100 parts by weight of the copolymerized polyester.
It is 5 to 10 parts by weight, preferably 0.1 to 3 parts by weight. If the amount is less than 0.05 part by weight, good antistatic performance cannot be obtained, which is not preferable. If the amount is more than 10 parts by weight, the improvement of the antistatic effect is no longer recognized, and the physical properties of the obtained composition are rather deteriorated.

For the synthesis of the copolymerized polyester of the present invention, generally known methods can be applied. For example, a first-stage reaction of directly esterifying an acid component with a glycol component or transesterifying a dialkyl ester of an acid with a glycol component to produce a glycol ester of a dicarboxylic acid or a low polymer thereof, and the formation of the reaction Most commonly, it is synthesized by a second step of subjecting the product to a polycondensation reaction.

The copolymerized polyester composition of the present invention is produced by blending a metal salt of an organic sulfonic acid represented by the formula (I) in the above-mentioned copolymerized polyester synthesis step or in the process of producing a film. The compounding time is preferably a stage before the intrinsic viscosity of the copolymerized polyester reaches 0.2, and particularly preferably a stage before the second stage after the completion of the transesterification reaction or the esterification reaction and before the polycondensation reaction.

In the present invention, a lithium compound or a potassium compound is preferably present in order to smoothly carry out the transesterification reaction or the esterification reaction. The lithium compound or the potassium compound is preferably a lower aliphatic carboxylate of lithium or potassium. It is preferred that 0.005 to 0.5 part by weight be present based on 100 parts by weight of the copolymerized polyester. Further, depending on the purpose, silica,
Inactive particles such as kaolin, talc, titanium oxide, calcium carbonate, and alumina, particles based on the contact residue precipitated in polyester, dyes, heat stabilizers, weathering agents, lubricants, antifoaming agents, and other optional compounds be able to.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples.

 In addition, the measured value of each characteristic is based on the following method.

A. The limiting viscosity of the polymer is o-chlorophenol
It was measured at 25 ° C.

B. The dispersibility of the antistatic agent was determined by melting the polymer between cover glasses, quenching, observing 10 visual fields with an optical microscope (200 times), and then classified into the following ranks.

:: Particle antistatic agent of 5 μ or more is present in less than 1.0.

Δ: 1.0 to 10.0 particulate antistatic agents of 5 μ or more are present in the visual field.

×: More than 10 particulate antistatic agents of 5 μ or more are present in the visual field.

 ○ or △ achieves the object of the present invention.

C. Heat resistance was measured by heating a ground polymer (diameter 1 mm or less) at 210 ° C. for 5 hours in air and classifying as follows according to the degree of decrease in intrinsic viscosity.

：: decrease in intrinsic viscosity is smaller than 0.15.

Δ: Intrinsic viscosity decreased from 0.15 to 0.20.

X: The decrease in intrinsic viscosity is greater than 0.20.

 ○ or △ achieves the object of the present invention.

D. Breaking strength is 10mm width × 50mm length film sample,
It was measured at a tensile strength of 300 mm / min and classified into the following ranks.

:: larger than 15 kg / mm ² .

^{△: 10~15kg / mm 2 ×:} 10kg / mm 2 smaller.

 ○ or △ achieves the object of the present invention.

E. The antistatic property was measured on the film using a super insulation meter (R-503, Kawaguchi Manufacturing Co., Ltd.) under the conditions of an applied voltage of 1000 V, 23 ° C., and 40% RH. The surface resistance is preferably 10 ¹⁴ Ω or less.

Examples 1-5, Comparative Examples 1-5 100 parts by weight of dimethyl terephthalate, 70 parts by weight of ethylene glycol and the amount of dimethyl 5-sodium sulfoisophthalate shown in Table 1 were added to magnesium acetate tetrahydrate.
0.06 parts by weight, 0.01 parts by weight of lithium acetate dihydrate and 0.03 parts by weight of antimony trioxide were added, and a transesterification reaction was carried out by a conventional method. To the obtained product, 0.05 parts by weight of phosphoric acid trimethyl ester was added, and then the amount of sodium dodecylbenzenesulfonate shown in Table 1 was added to gradually raise the temperature and reduced pressure. Finally, at 280 ° C. and 1 mmHg or less, Polymerization was performed to obtain a copolymerized polyester composition.

Using these copolymerized polyester compositions, 280 ℃
And extruded to produce an unstretched sheet. Then 80 ° C
The film is stretched 3.3 times in one direction at a temperature of 3.5 ° C, and further stretched 3.5 times in the perpendicular direction at a temperature of 90 ° C.
Was obtained. Table 1 shows the characteristic values of the polymer and the film.

As is clear from Table 1, the copolymerized polyester composition within the range specified in the present invention has excellent antistatic properties and heat resistance,
It can be seen that the dispersibility of the antistatic agent is good and the mechanical strength is also satisfied.

On the other hand, those out of the range of the present invention are inferior in antistatic property, heat resistance or mechanical properties.

Example 6 Instead of sodium dodecylbenzenesulfonate,
Polymerization and film formation were performed in the same manner as in Example 1 except that lithium stearylbenzenesulfonate was used to obtain a biaxially stretched film. As shown in Table 1, it is understood that the polymer and the film are excellent in antistatic property, dispersibility of antistatic agent, and heat resistance.

Example 7 A biaxially stretched film was obtained by polymerization and film formation in the same manner as in Example 1 except that dimethyl 2-sodium sulfoisophthalate was used instead of dimethyl 5-sodium sulfoisophthalate. The film, as shown in Table 1,
It turns out that it is excellent in antistatic property, dispersibility of an antistatic agent, and heat resistance.

[Effect of the Invention] The copolymerized polyester composition of the present invention improves the dispersibility of a metal salt of an organic sulfonic acid as an antistatic agent by copolymerizing a dicarboxylic acid having a sulfonic acid metal base at a specific ratio. In addition to being able to do so, the antistatic performance and heat resistance can be satisfied.

Therefore, the copolymerized polyester composition of the present invention has an excellent antistatic property, and is effectively used for forming a polyester film. In particular, when used for a magnetic tape film or the like, the effect is more remarkably exhibited.

Claims (1)

(57) [Claims] 1. A copolymerized polyester composition used for forming a film body of a polyester film having antistatic properties, wherein at least 70 mol% of the total acid component is terephthalic acid, and 0.05 to 10 mol% is sulfonic acid. Copolymerized polyester composition comprising 100 parts by weight of a copolyester that is a dicarboxylic acid having a metal base and 0.05 to 10 parts by weight of a metal salt of an organic sulfonic acid represented by the following general formula (I) as an antistatic agent: Stuff. (R—SO ₃ ) nM (I) [wherein, R represents an alkyl group, an aryl group or an alkylaryl group having 6 or more carbon atoms, and M represents an alkali metal or an alkaline earth metal. n is 1 when M is an alkali;
Is 2 when is an alkaline earth metal. ]