JPH03215588A - Water-soluble polyester antistatic agent - Google Patents

Abstract

PURPOSE:To obtain the title antistatic agent providing a uniform and transparent coating film by copolymerizing a specified amt. of polyethylene glycol and incorporating a specified amt. of an alkali metal salt in a polyester copolymer consisting of a dicarboxylic acid and/or an ester-forming deriv. thereof and a glycol. CONSTITUTION:In a polyester copolymer consisting of a dicarboxylic acid and/or an ester-forming deriv. thereof (e.g. dimethyl terephthalate) and a glycol, 80-95wt.% polyethylene glycol (with a number-average mol.wt. of 1,000-6,000) is copolymerized based on the wt. of the copolymer and 1-50wt.% one or more alkali metal salts (e.g. LiBr) are incorporated in the copolymer.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a water-soluble polyester antistatic agent that has excellent antistatic properties, transparency, coating properties on polyester resin products, and uniform coating film formation properties. It is.

(Prior Art) It is a well-known fact that the generation of static electricity has a great negative effect on the productivity, processability, commercial value, etc. of Plus Sennoku products. In order to solve such problems, a method is generally used in which an antistatic agent is applied to the resin surface or kneaded into the resin. This aims to reduce charge accumulation by lowering the surface resistivity or volume resistivity, but most of the antistatic agents currently in use have their own advantages and disadvantages, and it is difficult to achieve sufficient improvement effects. The reality was that there was little that could be done. For example, Japanese Patent Publication No. 58-12151 describes applying a solution containing block polyether ester and anionic surfactant, but the antistatic effect is at the level of 1011Ω in terms of surface resistivity, so it has even higher performance. In today's world, where there are many applications requiring high performance, it is not sufficiently effective, and because it uses a surfactant, its conductivity is easily affected by humidity and other factors, resulting in variations. Further, Japanese Patent Publication No. 12152/1983 describes that the adhesion of polyester films is improved by applying a solution containing polyethylene oxide as a main component having a molecular weight of soooo or more, but this alone does not sufficiently improve the conductivity.

In addition, in the case of the coating method, when forming a coating film on the surface of a resin product, if the wettability of the material is poor, the film thickness will be uneven or discontinuous, resulting in various problems such as variations in conductivity and poor appearance. .

(Problems to be Solved by the Present Invention) The purpose of the present invention is to solve the problems mentioned above regarding the coating method.
That is, the object of the present invention is to obtain a water-soluble polyester antistatic agent that has good coating properties and uniform coating film forming properties necessary to bring out sufficient antistatic performance, and has excellent antistatic performance.

(Another means to solve the problem) It has been reported that polyethylene glycol forms a complex with an alkali metal salt and exhibits ionic conductivity. The present inventors have conducted intensive studies with the aim of obtaining an excellent antistatic agent, taking into account uniform applicability, transparency, etc., and as a result, have discovered the present invention.

That is, the object of the present invention is to prepare a polyester copolymer consisting of a dicarboxylic acid and/or its ester-forming derivative and glycol, in which polyethylene glycol (number average molecular weight 1000 to 6000) is added to the copolymer weight by 8%.
0 to 95 weight χ copolymerized, and one or more alkali metal salts are added to the polyester copolymer at 1 to 50 weight χ
This can be achieved by providing a water-soluble polyester antistatic agent.

The dicarboxylic acids and/or their ester-forming derivatives used in the present invention include terephthalic acid, isophthalic acid, phthalic acid, 2,5-dimethylterephthalic acid, 2,
Aromatic dicarboxylic acids (or ester-forming derivatives thereof) such as 6-naphthalene dicarboxylic acid and biphenyldicarboxylic acid, 4-sulfoisophthalic acid, 5-sulfoisophthalic acid, sulfoterephthalic acid, 4-sulfophthalic acid, 4-
dicarboxylic acids (or ester-forming derivatives thereof) having a sulfonic acid group such as sulfonaphthalene 2,7-dicarboxylic acid and 5[4-sulfophenoxy]isophthalic acid;
Adipic acid, pimelic acid, azelaic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,
Examples include aliphatic or alicyclic dicarboxylic acids (or ester-forming derivatives thereof) such as 3-cyclopencune dicarboxylic acid and 4I4'-bink-hexyl dicarboxylic acid, but aromatic dicarboxylic acids are the main component. is preferable in terms of water resistance.

Polyethylene glycol has a number average molecular weight of 1000 to 6
000 is used within the range of 80 to 95 weight x based on the copolymer weight. If the weight of polyethylene glycol is less than 80% by weight, the water solubility of the polyester copolymer will be poor. Moreover, if it exceeds 95 weight χ, polycondensation becomes difficult. When the number average molecular weight of polyethylene glycol is less than 1000, the polyester copolymer is a sticky liquid at room temperature, making it difficult to handle and causing problems during use. 60 again
If it exceeds 00, the water solubility will be poor, and when a coating liquid is prepared, the viscosity of the coating liquid will be high and problems will arise in uniformity. As the glycol component other than polyethylene glycol, ethylene glycol is preferred, but 1,4-butanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, etc. may also be used.

The alkali metal salts used in the present invention include lithium bromide, sodium bromide, lithium iodide, sodium chloride, lithium chloride, potassium bromide, potassium thiocyanate, sodium thiocyanate, lithium perchlorate, lithium nitrate, etc. lithium salts are particularly preferred. Furthermore, these alkali metal salts are particularly preferably halogen compounds, thiocyanates, and perchlorates. It is preferable to use these in an amount of 1 to 50 weight χ, particularly preferably 2 to 10 weight χ, based on the weight of the polyester copolymer. If it is less than 1 weight χ, it is difficult to obtain stable conductivity, and if it exceeds 50 weight χ, the coating film will become sticky.
Not suitable for actual production.

A conventional method can be used for copolyester polymerization. For example, a method in which dimethyl ester of dicarboxylic acid and glycol are transesterified, methanol is distilled off, polyethylene glycol is added thereto, the pressure is gradually reduced, and polycondensation is carried out under high vacuum; A method in which an esterification reaction of glycol is carried out, the water produced is distilled off, polyethylene glycol is added thereto, the pressure is gradually reduced, and polycondensation is carried out under high vacuum, or dimethyl ester of dicarboxylic acid and dicarboxylic acid are used as raw materials. When an acid is used in combination, the transesterification reaction between dimethyl ester of a dicarboxylic acid and glycol is carried out, and the dicarboxylic acid is further added to carry out the esterification reaction. After adding polyethylene glycol to this, the pressure is gradually reduced and polycondensation is carried out under high vacuum. There are ways to do this. As the transesterification catalyst, manganese acetate, calcium acetate, zinc acetate, etc. can be used, and as the polycondensation catalyst, known ones such as antimony trioxide, germanium oxide, dibutyltin oxide, titanium tetrabutoxy, etc. can be used. In addition, as a stabilizer, phosphorus compounds such as trimethyl phosphate and triphenyl phosphate, Irganosox 101
A hindered phenol compound such as 0 may also be used. However, various conditions such as the polymerization method, catalyst, stabilizer, etc. are not limited to the above-mentioned examples.

In order to add an alkali metal salt to the obtained polyester copolymer, it is preferable to make the polyester copolymer into an aqueous solution and then add and mix the metal salt or its aqueous solution.

Further, other water-soluble or water-dispersible polymers may be added to this solution depending on the purpose, within a range that does not reduce the conductivity.

The term "water-soluble" as used in the present invention is not strictly physicochemically applicable, but also includes substances that are dissolved and/or finely dispersed in water. The water-soluble copolyester of the present invention preferably has an inherent viscosity of 0.8 dl/g or more.

If it is less than 0.8 d1/g, sufficient physical properties of the coating film cannot be obtained.

By applying the uniform solution obtained as described above onto a support such as a polyester film and drying it, it becomes possible to exhibit the effect of the antistatic agent as described in the present invention. The polyester support is preferably a film or sheet of polyethylene terephthalate, polyethylene naphthalate, or the like. It can be used as an antistatic agent alone or in combination with other water-soluble or water-dispersible polymers in a wide range of fields that require antistatic performance, such as hair films for photographic light-sensitive materials and various packaging materials. It is possible.

(Effects of the Invention) The antistatic agent of the present invention exhibits a surface resistivity of approximately 106 to 10l0Ω even when the product is in a dry state, and has good transparency and a uniform coating film. It has excellent performance, such as not causing variations in antistatic effect due to non-uniformity or discontinuity in film thickness, which are often seen in conventional antistatic agents.

(Example) The present invention will be specifically described below with reference to Examples and Comparative Examples.

[Evaluation method] (1) Intrinsic stiffness: Phenol/1,1,2.2-tetrachloroethane 60/40 (weight ratio) in mixed liquid, 20
Measured at °C.

(2) Water solubility: The polyester copolymer was stirred in hot water at 95° C. for 3 to 8 hours depending on the polymer, and the solubility and uniformity were visually evaluated.

(il 1 degree 15 weight χ) (3) Coating property: A coating solution was prepared so that the total concentration of the polyester copolymer and the alkali metal salt was 8 weight χ,
It was coated onto a polyethylene terephthalate biaxially oriented film support using a wire bar (coating liquid film thickness: 13.7 μm).

The coating state at that time was visually evaluated.

(4) Surface specific resistance; the coated film obtained in (3) was
The coating was dried with hot air at 00°C for 1 minute and then at 220°C for 2 minutes, and after cooling in a dry nitrogen atmosphere, the surface resistivity of the coated surface was measured. And further 23°C, 55χR}I
The temperature and humidity were controlled at (relative humidity) for 24 hours, and the surface resistivity of the coated surface was measured.

(5) Transparency: The coated surface of the polyethylene terephthalate film obtained in (4) was visually evaluated.

[Synthesis method of polyester copolymer A-F] Synthesis method No. 8 Dimethyl terephthalate 11.44 parts by weight, ethylene glycol 21.89 parts by weight, calcium acetate hydrate 0.0
3 parts by weight, 0.01 part by weight of manganese acetate tetrahydrate were subjected to a transesterification reaction at 170 to 220°C under a nitrogen stream while distilling off methanol, and then 0.043 parts by weight of trimethyl phosphate and polycondensation were performed. 0.04 parts by weight of antimony dioxide and 90.52 parts by weight of polyethylene glycol (number average molecular weight 3000) were added as catalysts, and the system was further reduced in pressure and heated to 280°C and 0.2 mmHg for 3 hours of polycondensation. I did it. At the end of the polymerization, after bringing the inside of the system to normal pressure under a nitrogen stream, Irganosox 1010 was added to 2.0
0 parts by weight was added and the reaction was terminated.

Analysis of the obtained copolymer revealed that the intrinsic viscosity was 1.48.
a/g, and the melting point was 56°C.

Various polymers were obtained using a synthetic method similar to the synthetic method A of B-F by changing the compositions of the dicarboxylic acid component and the glycol component. B-
The composition and physical properties of F are shown in Table 1.

Examples 1 to 6 Polyester copolymer A was stirred in hot water at 95°C for 3 hours to form a 15 weight x aqueous solution, and 1 to 10 parts of lithium bromide was added to 100 parts by weight of the polyester copolymer solid content in the solution. 5
0 parts by weight was added and further stirred uniformly.

This polyester copolymer aqueous solution was diluted with water to make an 8 weight χ aqueous solution, which was coated and dried on a polyethylene terephthalate film using a wire bar (the dry film thickness of the coated film was approximately 1 μm) and evaluated. It had good transparency and exhibited a surface resistivity of about 10 6 to 10 10 Ω even in a dry state. The evaluation results are shown in Table 2.

Examples 7 to 16 Polyester copolymer A was prepared in the same manner as in Examples 1 to 6.
and various alkali metal salts to obtain antistatic agents.

The evaluation results are shown in Table 2.

Examples 17-20 Table 2 shows the evaluation results when lithium bromide was added using polyester copolymers B and C in the same manner as in Examples 1-6.

Example 21 Polyester copolymer A was prepared in the same manner as in Examples 1 to 6.
Table 2 shows the evaluation results when other water-soluble polyester copolymer D was added and applied to the combination using lithium bromide. As described above, even when the antistatic agent of the present invention is used by adding it to other polymers, a large effect of improving conductivity can be obtained.

Comparative Example 1.2 Using polyester copolymer A, evaluation results are shown in Table 2 in the same manner as in Examples 1 to 6, when lithium bromide was not added and when 70 weight χ was added. In Comparative Example 1, the conductivity improvement effect was not obtained, and in Comparative Example 2, the conductivity, coatability, and transparency were good, but the coated surface was extremely sticky.
It could not be used for actual production.

Comparative Examples 3 and 4 Table 2 shows the evaluation results when polyester copolymer A was used and divalent and trivalent metals were added in the same manner as in Examples 1 to 6. In this case, the effect of improving conductivity in a dry state was insufficient, and in Comparative Example 3, clouding of the coating film was also observed.

Comparative Examples 5 to 7 Table 2 shows the evaluation results when lithium bromide was added to water-soluble polyester copolymer D having a composition outside the claimed range in the same manner as in Examples 1 to 6. In this case, there is no effect of improving conductivity, and the salt crystals are precipitated, making it extremely opaque.
Moreover, the coating film was non-uniform and could not be used.

In addition, polyester copolymers E and F having compositions outside the scope of the claims are listed as examples in Table 1, but E and F cannot be used as coating liquids due to poor water solubility and poor uniformity of aqueous solutions, respectively. Met.

A: Immediately after heat fixation, surface roughness value B under nitrogen atmosphere
:23°C×55χRH Xca. Surface stiffness resistance value after 24 hours Coating properties: O: Uniform ×: Uneven coating Transparency: ○: Transparent Δ, almost transparent ×: Cloudy Addition ratio of A/D / 60 (wtχ) Significant stickiness on the coated surface

Claims (1)

[Claims] 1. A polyester copolymer consisting of dicarboxylic acid and/or its ester-forming derivative and glycol, polyethylene glycol (number average molecular weight 1000 to
6000) is copolymerized in an amount of 80 to 95% by weight based on the weight of the copolymer, and one or more types of alkali metal salts are added in an amount of 1 to 50% by weight based on the polyester copolymer. Antistatic agent.