JPS5946254B2 - Method for producing polyester with excellent particle dispersibility - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an improved process for making polyester to make polyester films or fibers.

Specifically, the present invention relates to a method for producing linear polyester that can improve the uniform dispersibility of fine particles containing silicon oxide as a main component and produce fibers or films with excellent slipperiness and transparency. More specifically, in the process of manufacturing linear polyester mainly composed of polyethylene derephthalate, a basic compound consisting of a quaternary ammonium compound is added to finely divided silicon oxide to adjust the pH to 7.0 to 10.5. The present invention relates to a method for producing polyester in which fine particles are well dispersed by adding the adjusted mixture after adjustment.

When polyester containing polyethylene terephthalate as the main component is used as transparent clothing fiber, packaging film, microfilm, or vapor-deposited film, the most important properties are transparency and slipperiness, as well as uniformity of surface irregularities. and miniaturization.

Conventionally, various catalysts have been studied and many methods have been proposed for the purpose of improving transparency. However, since all of these methods place emphasis only on transparency, the resulting fibers or films have the drawback of being extremely poor in slipperiness. Particularly in the case of polyester films, if the surface is not slippery, adhesion between the films will occur, which will not only reduce work efficiency during film formation or post-processing, but also deteriorate the rolled appearance, significantly reducing the product value. Don't cause problems such as deterioration. Furthermore, recently, aluminum has been added to the surface of polyester film.
The use of metallized films made by vapor-depositing metals such as zinc or sputtering palladium, platinum, etc. is expanding. A problem has arisen in which the difference in glossiness becomes large. In order to solve these problems, many methods have been proposed to improve the properties of polyester by adding inert inorganic particles to it.

For example, methods have been proposed in which inorganic compounds such as titanium oxide and clay are added alone or in combination to improve slipperiness. However, in order to improve the slipperiness by these methods, it is necessary to increase the amount of the above-mentioned additives, which results in a loss of transparency, which is an important property for fibers or films. Furthermore, slipperiness cannot be improved if the amount added does not impair transparency. Therefore, in order to produce a film with excellent transparency and slipperiness, for example, kaolinite, as in French Patent No. 1347696 I,
Methods of adding inorganic compounds such as talc, calcium phosphate hydride, and magnesium carbonate have also been proposed, but since these are pulverized natural products, coarse particles are inevitably mixed in, making it impossible to obtain a homogeneous film. On the other hand, methods for adding silicon oxide to polyester to improve slipperiness include adding it during polymerization of polyester, mixing it with polyester chips during extrusion film formation, and then forming it into fibers or films after melt extrusion. Although it has been proposed that especially when a film is manufactured by this method, the slipperiness of the film can be effectively improved. Because silicon oxide has extremely poor dispersibility, it aggregates during polymerization or in the extruder, and when it is formed into a refilm, many coarse particles are scattered on the film surface, which not only reduces the transparency of the film but also makes it difficult to make an ultra-thin film. This was a major hindrance in manufacturing.

Similarly, in Japanese Patent Publication No. 43-23960, fine particles (talc) mainly composed of silicon oxide and magnesium oxide are used in the presence of tertiary amines, quaternary ammonium compounds, etc. for the purpose of making polyester films slippery and transparent. A method is described in which the particles are added at any point during the transesterification reaction or polymerization reaction.

However, the resulting chips are littered with agglomerated particles that can form sticky eyes when film-formed, resulting in extremely unfavorable results in terms of operation, such as film breakage, as well as quality, such as opacity and changes in gloss ratio. . Furthermore, it is also possible to add silicon oxide as it is in the presence of an alkali compound at any stage until the polymerization is completed, but this method also suffers from the same drawbacks as in the case of talc. As a result of intensive research to solve such problems, the present inventors have found that
Rather than subjecting silicon oxide to such treatment as it is, we succeeded in solving these drawbacks by using silicon oxide with specific physical properties, using a special alkali compound, and investigating a method for preparing it.

That is, in the present invention, in the method of adding silicon oxide to polyester, BE
The surface area measured by the T method is 250m7f or less, the average particle diameter of primary particles is 20mμ to 100mμ, and the pH is 3.5
~4.5 silicon oxide is treated with a basic compound consisting of a quaternary ammonium compound to adjust the pH to 7.0 to 10.5, and then at any stage until the polymerization of the linear polyester is completed. This is a method for producing polyester with excellent dispersibility by adding

In the present invention, polyester refers to a low polymer obtained by transesterification or esterification of a dicarboxylic acid whose main component is terephthalic acid or its ester-forming derivative and a glycol whose main component is ethylene glycol. It is used for polycondensation.

The dicarboxylic acid component used as a raw material for polyester in the present invention is mainly terephthalic acid or its lower alkyl ester.
Aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, 5-sodium sulfoisophthalic acid, and naphthalene dicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid and sebacic acid, and p-β-oxyethoxybenzoic acid in a range of 0 mol% or less. and ester-forming derivatives thereof.

As for glycols, ethylene glycol is the main target, but some of them include diethylene glycol, propylene glycol, trimethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol, 1,4-bisoxyethoxybenzene, bisphenol A, It may be replaced with polyoxyethylene glycol or other diols. Typical catalyst systems used for polycondensation in the present invention are glycol-soluble antimony, titanium, or germanium compounds, such as antimony trioxide, antimony potassium tartrate, antimony oxychloride, germanium oxide, and tetraalkyl titanates. Preferably used.

The method for dispersing silicon oxide in the present invention includes adding silicon oxide to water, ethylene glycol, or a mixed solution of ethylene glycol and water, and further adding at least one kind of quaternary ammonium compound.
Finely dispersed by high speed stirring, the pH should be 7.0~
It is necessary to adjust it within the range of 10.5.

If the pH is less than 7.0, generation of coarse particles cannot be prevented.
On the other hand, when the pH exceeds 10.5, silicon oxide becomes solubilized in the mixed solution and is precipitated as large particles in the polyester. It is also preferable to use high-speed shearing and heating at 100° C. or less in combination to make the silicon oxide fine. In the present invention, if silicon oxide and the basic compound are separately added to the polymerization system, satisfactory results cannot be obtained. Further, in the present invention, silicon oxide may be added before the completion of the polymerization reaction, and can be added, for example, at any stage of esterification, transesterification, or polymerization.

If it is added after the polymerization is completed, the dispersibility will be extremely deteriorated. Examples of the quaternary ammonium compound used as the basic compound of the present invention include compounds such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetraethylammonium halide, and tetraethylammonium alcohol. The mixing ratio of each component constituting the mixture of the present invention is preferably 1 part water or ethylene glycol (or water mixed system).
0.5 to 20 parts by weight of silicon oxide, and the amount of the basic compound is 0.5 to 10 parts by weight, preferably 1.0 to 3.0 parts by weight, based on 100 parts by weight of silicon oxide. You can achieve your goals in the weight department.

The silicon oxide in the present invention refers to silicon oxide obtained by a dry method by burning silicon nitride, and has a surface area of 250 m"/y or less, preferably 150 to 25
0i/y, and the average particle diameter of the primary particles is 20 to 100 m.
It is an amorphous silicon dioxide having a μ and a pH of 3.5 to 4.5.

The surface area of silicon dioxide, the average particle diameter of the primary particles, and the pH have extremely large effects on agglomeration in polyester, and in cases outside the scope of the present invention, even if the treatment of the present invention is carried out. Secondary aggregation is likely to occur during polymerization, and when formed into a film, it not only significantly impairs transparency but also deteriorates the surface gloss ratio after metal vapor deposition. The amount of silicon dioxide added can be varied depending on the purpose of production, but it is suitably in the range of 0.01 to 1.0% by weight, particularly preferably 0.03 to 0.0% by weight, based on the polyester.
It is in the range of 3% by weight. If the amount added is less than 0.01% by weight, there is no effect on slipperiness, and if it exceeds 1.0% by weight, the transparency targeted by the present invention cannot be achieved. Note that the PH of silicon oxide and the PH of silicon oxide adjusted by treatment with a basic compound in the present invention were measured by the following method.

(PH of silicon oxide) Silicon oxide is dispersed in ion-exchanged water to form a 10% by weight dispersion, and the pH of the dispersion is defined as the pH of silicon oxide.

(PH of silicon oxide adjusted by treatment with basic compound)
) The pH of silicon oxide adjusted by adding a specific amount of a basic compound to a 10% by weight dispersion of silicon oxide in ion-exchanged water is the same as the pH of silicon oxide adjusted by treating with a basic compound. do.

Note that other reaction accelerators, quality improvers, and coloring additives may be added during polymerization of the polyester of the present invention.

When the polyester chips obtained according to the present invention are melt-spun, stable spinning for a long period of time with a very small increase in f pressure can be obtained, and when the polyester chips are drawn and made into filaments, they have good processability, and titanium oxide is added. A more unique and desirable gloss can be obtained.

It also has the advantage that the wear of various guides that come into contact with it during machining is significantly reduced compared to titanium oxide. Further, when a film is obtained by biaxial stretching after melt molding, a film with fine surface irregularities, excellent lubricity and transparency, and good workability in handling the film can be obtained. When a metal such as aluminum is vapor-deposited on one side of this film, a vapor-deposited film with extremely small difference in gloss between the front and back surfaces can be obtained. The present invention will be specifically described below with reference to Examples.

The transparency, slipperiness, glossiness ratio and pressure increase of the film were measured in the following manner. (Transparency of film) Film haze was measured five times according to the ASTM-D-1003-52 method, and the average value was used as a measure of film transparency, which was ranked as follows.

(Film slipperiness) AST using a slip tester manufactured by Toyo Tester Co., Ltd.
The coefficient of static friction measured according to the MD-1894B method was used as a measure of slipperiness, and ranked as follows.

(Difference in Glossiness of Film) One side of the film was subjected to aluminum vapor deposition, and JIS was measured using a variable angle photometer VG-107 manufactured by Nippon Denshoku Industries Co., Ltd.
-Z874l6OO The glossiness of the deposited surface and the non-deposited surface was measured by the specular gloss method, and the difference in glossiness was ranked as follows based on the ratio.

(Increase in pressure) Using a 30 mmφ extruder with L/D = 22 and a semi-compression type screw with a compression ratio of 30, the feed part temperature was 230°C, the compression part temperature was 290°C, and the metering part temperature was 295°C. and set a "UgiI" G-15 plate filter (50mmφ) at the tip of the extruder.
), and the difference between the pressure at the beginning of extrusion (K9/Cri.) and the pressure after discharging the polymer 10k9 (K9/Cd) was used as a measure of filterability.

Example 1 1.9 to 100 parts by weight of dimethyl terephthalate
Add twice the mole of ethylene glycol, and then add calcium acetate monohydrate [(CH3COO)2Ca-H2O] 0.0
9 parts by weight of antimony oxide and 0.03 parts by weight of antimony oxide were added and heated to 150 to 230°C under a nitrogen atmosphere to perform a transesterification reaction while continuously distilling the generated methanol out of the system. The reaction was completed in time.

Subsequently, 0.04 parts by weight of trimethyl phosphate was added to the obtained product, which was further treated with tetraethylammonium hydroxide to adjust the pH to 9.0. Ethylene glycol slurry of silicon oxide (silicon oxide concentration: 10% by weight) ) was added so that the amount of silicon oxide was 0.07 parts by weight.
Next, the pressure of the system was gradually reduced to 290°C, 1 mmH.
Polycondensation was carried out for 3 hours and 55 minutes under a reduced pressure of 1.5 g to obtain various polyesters containing silicon oxide (intrinsic viscosity of 0.5 g) having different particle surface areas and average primary particle diameters as shown in Table 1. 620, softening point 261°C). Further, each polyester was formed into chips, dried under reduced pressure at 180°C for 3 hours, formed into a sheet using an extruder set at 295°C, and then biaxially stretched at 95 to 130°C to obtain a biaxially stretched film of 25μ.

The results of measuring the transparency, slipperiness, and difference in gloss of the biaxially stretched film are shown in Table 1. In Table 1, experiment numbers 1, 5, 8, 9, and 10 are comparative experiments for clarifying the effects of the present invention. Table 1 shows that even if the particle surface area is the same, the film properties change depending on the average particle size of the primary particles, and even if the average particle size is the same, the film properties change depending on the particle surface area. it is obvious.

In other words, it is clear that in order to obtain a film that satisfies the three properties of transparency, slipperiness, and glossiness at the same time, it is necessary to carefully examine and select the particle surface area and the average particle diameter of the primary particles. Example 2 Average particle size of primary particles of 200 i/y1 determined by BET method, pH 4. A biaxially stretched polyethylene terephthalate film with a thickness of 25 μm was prepared in the same manner as in Example 1, except that O silicon oxide was used and the pH of the silicon oxide was adjusted to various values as shown in Table 2. Obtained.

The properties of the obtained biaxially stretched film are as shown in Table 2. In addition, in Table 2, experiment numbers 11 and 1
7 is a comparative experiment to clarify the effects of the present invention.
From Table 2, in order to sufficiently disperse silicon oxide, the pH is
It is clear that it is necessary to adjust the value to an appropriate range. Example 3 The surface area measured by the BET method was 200 WI/t, the average particle diameter of primary particles was 40 mμ, and the pH was 4. A biaxially stretched polyethylene terephthalate film having a thickness of 25 μm was prepared in the same manner as in Example 1, except that O silicon oxide was used and the basic compound for adjusting the pH of the silicon oxide was as shown in Table 3.

The properties of the obtained film are shown in Table 3. In Table 3, experiment numbers 20 and 21 are comparative experiments for clarifying the effects of the present invention.

It can be seen from Table 3 that alkaline compounds such as sodium polyphosphate and caustic soda have very little effect on dispersibility, and the resulting films are particularly poor in transparency. Example 4 1.9 times the mole of ethylene glycol was added to 100 parts by weight of dimethyl terephthalate, and further 0.09 parts by weight of calcium acetate monohydrate and 0.03 parts by weight of antimony oxide were added, and the mixture was heated at 150 to 100 parts by weight under a nitrogen atmosphere. The transesterification reaction was carried out by heating to 230° C., and the transesterification reaction was completed 3 hours after the start of the reaction while continuously distilling the generated methanol out of the system.

Subsequently, 0.04% of trimethynol phosphate was added to the obtained product.
Part by weight, and further 10% by weight of silicon oxide having a surface area of 200 d/t, an average primary particle diameter of 40 mμ, and a pH of 4.0.
Concentrated ethylene glycol slurry and! Tetraethylammonium hydroxide was added to the slurry to adjust the pH to 10.
After adjusting the amount to 0.0, silicon oxide was added in an amount of 0.07 parts by weight. Then, the system was gradually reduced in pressure, and finally polycondensation was carried out at 290° C. and under a reduced pressure of 1 mmHg for 3 hours and 40 minutes. The obtained polyethylene terephthalate had an intrinsic viscosity of 0.615 and a softening point of 260.5°C. The obtained polyethylene terephthalate was processed in the same manner as in Example 1 to form a biaxially stretched film with a thickness of 25 μm. The transparency, slipperiness, glossiness difference, and flow characteristics of the biaxially stretched film are shown in Table 4. As shown in Figure 2, the results were extremely good. Furthermore, when the biaxially stretched film was used to vapor-deposit A1 metal on one side, a metal-deposited film with very good surface gloss with little difference in gloss between the front and back surfaces was obtained. Furthermore, the obtained polyethylene terephthalate was made into chips, dried under reduced pressure at 180°C for 3 hours, and then spun and stretched using a conventional method to obtain filaments of 70D and 24F.Filaments with extremely excellent yarn-based friction coefficients and gloss were obtained. Ta.

Comparative Example 1 A biaxially stretched polyethylene terephthalate film having a thickness of 25 μm was obtained in exactly the same manner as in Example 4, except that sodium polyphosphate was used as the basic compound for adjusting the pH of silicon oxide.

The properties and flow resistance of the film are shown in Table 4, and these properties were all inferior to those of Example 4. Example 5 1.4 times the mole of ethylene glycol was added to 100 parts by weight of terephthalic acid, 0.007 parts by weight of monobutyltin oxide and 0.03 parts by weight of antimony oxide were added as catalysts, and the mixture was heated under a pressure of 4 kg/Cd. The esterification reaction was carried out while heating to 240° C. and continuously distilling the produced water out of the system, and the reaction was completed 6 hours after the start of the reaction.

Claims (1)

[Claims] 1 Among silicon oxides obtained by dry method, the surface area by BET method is 250 m^2/g or less, the average particle size of primary particles is 20 mμ to 100 mμ, and the pH is 3.5 to
After treating the silicon oxide of 4.5 with a basic compound consisting of a quaternary ammonium compound and adjusting the pH to 7.0 to 10.5, at any stage until the polymerization of the linear polyester is completed. A method for producing polyester with excellent particle dispersibility, characterized by the addition of polyester.