KR930001996B1 - Polyester resin composition - Google Patents

Abstract

The polyester composition is prepared by adding and polymerising 0.5-10 wt.% of sulfonic acid metallic salt of formula (I) in the process of reacting aromatic dibasic acid and glycol. In the formula, R1 and R2 are H or C1-15 alkyl; the sum of number of cabon atom of R1 and R2 is 5-20; n is 0-25; m is 1-4; M is alkali metal. The biaxial oriented polyester film is mfd. by melt-extruding the obtd. polyester compsn. at 80-110 deg.C elongation temp. in direction of length, then elongating in drection of width, and then heat-treating at 225-240 deg.C to treat by corona discharge. The obtd. film has excellent adhesive and antistatic properties and useful for pakage.

Description

Manufacturing method of polyester composition and film excellent in adhesiveness and antistatic property

The present invention relates to a polyester composition excellent in print adhesiveness and antistatic property and a method for producing a biaxially oriented film using the composition.

In general, biaxially oriented polyethylene terephthalate film is used for general packaging fields such as food packaging, textile packaging, pharmaceuticals, chemicals, packaging, industrial parts packaging, protective film, transfer, etc. Films, evaporation applications, tracing papers, second raw papers, and films for projectors are widely used.

Among them, in the field of food packaging, odorlessness, hygienic consideration of residual solvent amount, limitation of printing solvent, and excellent drying property are important requirements.

Therefore, the printing ink to be printed on the packaging material is required to have excellent desolvability, and such printing ink is superior to other inks for cellulose-based films using a cellulose derivative as a binder. However, the ink for the cellulose-based film does not have sufficient adhesive strength when printing on the polyester film, and there is a defect that is easily peeled off during the hydrothermal treatment.

In order to solve this problem, various methods through corona discharge treatment and polymer modification have been proposed. However, corona discharge treatment is insufficient due to elapsed time and uneven treatment depending on the elapsed time and the surrounding environment, and the polymer modification method also improves the printing adhesion, but the problem of frictional charging of the polyester film remains.

The generation of static electricity due to the friction of the polyester film causes the packaged material in the form of powder and particles, especially when the packaged material is in a dry state, to adhere to the package and deteriorates the appearance, and to heat seal parts during automatic packaging. (Heat-Sealing parts) attaches a part of the package, making it impossible to protect its contents. In addition, when printed on the package, the precise printing is impossible due to the generation of static electricity, the printed content is not clear.

In the meantime, many techniques regarding the method of manufacturing polyester film having print adhesive strength and antistatic properties have been proposed.

Conventionally, polyethylene glycol and alkylated aromatic sulfonate have been added during polyester polymerization for the purpose of easy adhesion and antistatic, thereby producing a polyester film.

That is, in the conventional method,

1. A polyalkylene ether glycol having a low specific resistance is coated on a polyester surface (JP-A-41-13568).

2. Styrene oligomer and sulfonic acid metal salt are added during polymerization (JP-A-56-53148)

3. The method of adding polyalkylene glycol and alkylated aromatic sulfonate at the time of the polyester superposition | polymerization (JP-A-52-47071) etc. is mentioned.

However, these known methods have the following problems. Coating the surface of polyalkylene ether glycol with low specific resistance decreases the volume resistivity, but the surface resistivity does not decrease significantly, and a separate coating process is required for film formation. In addition, the styrene oligomer and the sulfonic acid metal salt are simultaneously The addition of esters during polymerization or the addition of polyalkylene glycols and alkylated aromatic sulfonates is not only complicated in the polymerization process but also does not have sufficient print adhesion and antistatic properties in practical use.

MEANS TO SOLVE THE PROBLEM The present inventors completed the present invention as a result of careful and steadily researching in order to solve the problems of the aforementioned prior arts. The inventors of the present invention surprisingly improve the printing adhesion and antistatic effect of a biaxially oriented polyester film by adding an anionic surfactant represented by the following general formula (I) at the time of polymerization of a polyester composed of a dibasic acid residue and a glycol residue. I found the facts.

In general formula (I), R <_1> and R <_2> is a hydrogen atom or the alkyl group of 1-15 carbon atoms, The sum of the number of carbon atoms of R <_1> and R <_2> is 5-20, n is 0-25, m is 1 To 4 and M is an alkali metal.

Therefore, an object of the present invention is a polyester composition improved by the addition of the anionic surfactant represented by the general formula (I) at the time of the polymerization of the polyester and the antistatic effect and the print adhesion and antistatic using the composition It is to provide a method for producing a polyester film with improved effect.

In the present invention, the dibasic acid residue is mainly terephthalic acid, but other isophthalic acid, adipic acid, sebacic acid, 2-6-naphthalenedicarboxylic acid may be used, and the glycol residue is usually alkylene glycol, ethylene glycol, propylene glycol, trimethylene Glycol, tetramethylene glycol, etc. are used, but practically, ethylene glycol or tetramethylene glycol is suitable. The molecular weight of the sulfonic acid metal salt represented by general formula (I) is 300-1500, Preferably it is 500-1500.

That is, the polyester composition and the film of the present invention is at least 80% by weight of the component is polyethylene terephthalate, the sulfonic acid metal salt represented by the general formula (I) at any point before the completion of the polyester polymerization 0.5-10 A polyester film chip was prepared by adding 1% by weight, more preferably 1-5% by weight, followed by longitudinal stretching at the stretching temperature of 80-110 ° C. in the film forming process, followed by the stretching in the width direction of 225 ° C. or more and 240 ° C. It is obtained after heat-treatment for 5 seconds or less and then performing corona discharge treatment of appropriate strength in an air and nitrogen atmosphere.

Here, when the sulfonic acid metal salt represented by the formula (I) is added at 0.5 wt% or less, the adhesion strength with the printing ink is lowered and the antistatic effect is decreased. The adhesion strength with the printing ink is lowered by inhibiting the excess and excessive transition to the surface of the surfactant. In addition, when the longitudinal stretching temperature is 80 ℃ or less occurs the thickness non-uniformity caused by necking (Necking) and when the temperature is 110 ℃ or more, the crystallization of the stretched film is excessively progressed, causing a decrease in transparency and peeling during the lateral stretching. On the other hand, when the heat treatment temperature is less than 225 ℃ the surface migration of the surfactant is less, the adhesion and antistatic effect with the printing ink is lowered, when the heat treatment at 240 ℃ or more lower the mechanical properties of the final film. After the corona treatment, the adhesion to the printing ink is further improved, and even after the corona treatment, the generation of static electricity is significantly reduced due to the effect of the surfactant.

The thickness of the final film obtained in the present invention can be up to 10μm-200μm, but the main use is for general packaging of 10μm-50μm.

By the polarity and hydrophilicity of at least one ethylene oxide group of the sulfonic acid metal salt represented by the general formula (I) used in the present invention, the adhesion to the ink for cellulose film is improved, and also antistatic is made, and -SO ₃ M As a result, the antistatic effect is doubled, and the adhesion to the printing ink is reinforced by corona treatment, so that the packaging film can be obtained with excellent ease of printing and adhesiveness of the final biaxially oriented polyester film and excellent antistatic effect. In this invention, the method of measuring the characteristic value of a film is as follows.

1) Film transparency (film haze)

According to ASTM D1003 standard, it measured with NDH 1001 DP haze meter of Nippon Color Industry Co., Ltd.

2) Print Ink Adhesive Strength

Using a printing ink CC-ST for ink of cellophane film manufactured by Samyoung Ink Co., Ltd., it was applied to the film surface so that the coating thickness was 1.0 μ, dried at 70 ° C. for 1 minute in a hot air dryer, and then cellophane tape (width: 18 mm) ) Was repeated five times by hand on the ink coating surface to prevent bubbles from being formed.

(Double-circle): It does not peel at all (good)

○: barely peeled off (good -10% or less)

: 10%-50% 박리된다(조금불량)

: 10% -50% peeled off (slightly poor)

X: 50% or more easily peeled off (defect)

3) Antistatic

The films were rubbed for 1 minute at 65% RH at 20 ° C using Rotary Rotary Tester manufactured by Heunga Sangyo Co., Ltd., and expressed as half-life of the frictional voltage.

: 조금불량 × : 불량)(○: Good

: A little defective ×: Poor)

4) Surface specific resistance

Using the "ANDO TRS-10" method (Japan), determine the resistance value that appears when electrons pass through the film surface as a conductor, and then obtain the surface resistance by the following equation.

δ _s : Surface specific resistance (Ω cm)

R: Surface resistance measurement (Ω)

d: distance between the main electrode and the auxiliary electrode (cm)

l: center line circumference between the main electrode and the auxiliary electrode

Next, the present invention will be described in more detail as Example 1 and Comparative Examples.

Example 1

1) 90 parts of dimethyl terephthalate, 54 parts of ethylene glycol, 0.035 parts of antimony trioxide, 0.085 parts of calcium acetate phosphate were placed in a transesterification tube, heated to 230 ° C. for 4 hours, and completed the transesterification reaction while distilling methanol. 0.15 parts of average particle diameter was stirred for 10 minutes, and then transferred to a polymerization tube, where 0.045 parts of trimethyl phosphate and R ₁ and R ₂ in the general formula (I) were ethyl groups, n was 20, m was 3, and M was Na. 1.0 part of sulfonic acid metal salts (normal molecular weight 1000) were added, and the polyester polymer composition of intrinsic viscosity 0.63 was obtained after about 4 hours, heating up and reducing pressure to 0.1 mmHg and 285 degreeC.

2) Next, the polyester chip was dried at 160 ° C. for about 10 hours, melt-compressed at 285 ° C. to obtain an unstretched film, stretched 3.8 times in the longitudinal direction at a longitudinal stretching temperature of 100 ° C., and stretched again in the width direction 235. After heat treatment at 10 DEG C for 10 seconds, a blast furnace or discharge treatment of appropriate strength was carried out in a nitrogen atmosphere to obtain a final biaxially oriented polyester film of 12 mu.

Example 2

The polyester polymer was reacted by adding 0.5 parts of sulfonic acid metal salt in which R ₁ is ethyl, R ₂ is propyl, n is 15, m is 2, and M is Li in structural formula (I). A composition was obtained. Next, the heat treatment temperature in the method 2) of Example 1 was 238 degreeC, and the remainder was processed similarly and the polyester film was obtained.

Example 3

The polyester polymer was reacted by adding 0.3 parts of a sulfonic acid metal salt in which R ₁ is H, R ₂ is pentyl, m is 20, n is 3, and M is K in Structural Formula (I). A composition was obtained.

Next, the polyester film was manufactured by treating the drawing in the longitudinal direction to 110 ° C. and the heat treatment temperature at 228 ° C. in a similar manner to 2) of Example 1.

Comparative Example 1

The reaction was carried out by a method similar to that of Example 1, except that only 0.3 part of the sulfonic acid metal salt of formula (I) was added to produce a film.

Comparative Example 2

The reaction was carried out in the same manner as in Example 1 without adding the sulfonic acid metal salt represented by Structural Formula (I) to prepare a film.

Comparative Example 3

Reactions and films were prepared in the same manner as in Example 1, but no corona treatment was performed.

Comparative Example 4

Instead of the sulfonic acid metal salt represented by the general formula (I), 2.0 parts of C ₁₇ H ₃₅ SO ₃ Na was added thereto to react as in Example 1), and the film was prepared in the same manner as in Example 1, 2).

Comparative Example 5

Instead of the sulfonic acid metal salt represented by the general formula (I), 2.0 parts of polyalkylene glycol was added and reacted as in Example 1), to prepare a film as in Example 2).

Physical properties of the films prepared in Examples and Comparative Examples are shown in Table 1 below.

TABLE 1

As confirmed in Table 1, it can be seen that the physical properties of the polyester composition of the present invention and the film prepared therefrom are excellent.

Claims (4)

In preparing a polyester polymer by reacting an aromatic dibasic acid and a glycol, a poly excellent in adhesion and antistatic properties to a printing ink obtained by adding 0.5-10% by weight of a sulfonic acid metal salt represented by the following general formula (I) to polymerize Ester polymer composition.

Provided that R ₁ and R ₂ are hydrogen atoms or alkyl groups of 1 to 15 carbon atoms, the sum of the number of carbon atoms of R ₁ and R ₂ is 5 to 20, n is 0 to 25, m is 1 to 4 and M is alkali Metal. In preparing a polyester polymer by reacting an aromatic dibasic acid with a glycol, 0.5-10% by weight of a sulfonic acid metal salt represented by the following structural formula (I) is added and reacted to the polyester to have excellent adhesion and antistatic properties to a printing ink. A method of making a polymer composition.

Provided that R ₁ and R ₂ are hydrogen atoms or alkyl groups of 1 to 15 carbon atoms, the sum of the number of carbon atoms of R ₁ and R ₂ is 5 to 20, n is 0 to 25, m is 1 to 4 and M is alkali Metal. The polyester polymer composition obtained in claim 1 is melt-extruded to have a longitudinal stretching temperature of 80-110 ° C., stretched in the width direction, and heat-treated at 225 ° C.-240 ° C., followed by a corona discharge treatment. Biaxially oriented polyester film for packaging with excellent adhesiveness and antistatic effect. Printed ink obtained by melt extruding the polyester polymer composition obtained in claim 1 to be extended in the longitudinal direction at a longitudinal stretching temperature of 80 ° C. to 110 ° C., followed by heat treatment at 225 ° C. to 240 ° C., followed by corona discharge treatment. A method for producing a biaxially oriented polyester film for packaging excellent in adhesion and antistatic properties.