JPS641492B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a biaxially oriented polyethylene terephthalate film containing fine particles, particularly a film-forming polyester that is effective in increasing the film forming speed and has excellent transparency and handling properties. In recent years, polyethylene terephthalate films have been used in increasing amounts for magnetic tapes, photographs, and capacitors, and in particular, the field of transparent films, such as microfilms and stamping foils, has made remarkable progress. However, when attempting to manufacture products that take full advantage of its brightness and transparency, problems often occur due to insufficient slip in the film forming process and film high-order processing process. Particularly in the manufacturing process of biaxially oriented films, when increasing the film forming speed to increase production efficiency, for example, when applying a high voltage casting method to increase the film forming speed by 1.5 times or more at once. There was a problem that high voltage casting characteristics and winding characteristics became poor. The above-mentioned problem during casting during high-speed film production is that air becomes interposed between the cooling drum and the film, which slows down the cooling rate of non-contact parts of the cooling drum, resulting in uneven thickness and non-uniform mechanical properties. This is due to this. As a method to improve this problem, for example, as described in Japanese Patent Publication No. 37-6142, a method is known in which an electrostatic charge is applied to the surface of a molten thermoplastic sheet and the sheet is brought into close contact with a cooling surface. It has become possible. However, if a non-particle-filled polyethylene terephthalate sheet is held at a potential sufficient to generate an electrostatic charge to bring the sheet into close contact with a cast drum, pinholes will form in the molten polyethylene terephthalate sheet due to sparks, discharge, etc. In addition, problems arise in which adhesion is impaired due to potential drop due to discharge. In addition, particle-free polyethylene terephthalate film has an unacceptably large film-to-film friction coefficient during the film forming process, resulting in block formation during winding. There is a problem in that poor winding occurs frequently due to insufficient frictional properties between the deposited metal and the film. Many techniques have been proposed and implemented to overcome these difficulties, but they can be broadly divided into (1) Adding inert fine particles to the polyester synthesis reaction system such as titanium dioxide, talc, kaolinite, calcium carbonate, etc. (hereinafter referred to as the external particle addition method) (2) A method in which part or all of the catalyst, color inhibitor, etc. used during polyester synthesis are precipitated during the reaction process to exist as fine particles (hereinafter referred to as the internal particle generation method) There is. However, the external particle addition method has a number of drawbacks as follows. In other words, when using fine particles with strong hiding power such as titanium dioxide, which is commonly used, there is a problem that it becomes opaque in fields where transparency is required, and it also has poor properties as a crystallization nucleating agent, making it difficult to use as an easily slippery film. A sufficient surface roughness is not achieved. Furthermore, when using talc, kaolin, etc. as a particle source, the hiding power is relatively weak, so the upper limit of the amount added to maintain transparency and crystallinity is considerably reduced compared to the case of titanium dioxide. However, when a metal such as aluminum is vapor-deposited on one side of the resulting film, there is a problem that the appearance deteriorates. The reason for this is that these particles are often obtained by crushing natural minerals, so the proportion of coarse particles mixed in, the roughness of the average particle size, and the coarse particles due to agglomeration during mixing, in the case of titanium dioxide. It becomes so obvious that it is difficult to compare. Moreover, all of these particles added by external particle addition methods lack compatibility with the polyester matrix and often cause agglomeration during the polyester synthesis process. For example, silicon dioxide, which is commonly used in other types of plastics, is difficult to uniformly disperse in polymers as shown in Japanese Patent Publication No. 43-23960. As mentioned above, in order to obtain a film with good transparency and slipperiness using the external particle addition method, it is important to select the particles to be added and to uniformly disperse them so that there are no coarse particles. On the other hand, in the internal particle generation method, the disadvantages of the external particle addition method are improved to some extent. Examples of using calcium as an internal particle generation method are already known. For example, when an alkaline earth metal is used as a transesterification catalyst in Japanese Patent Publication No. 34-5144, insoluble particles are generated in the polymer, and these are terephthalate particles. It is stated that it is an alkaline earth metal salt of an acid. In addition, in order to reduce the dynamic friction coefficient of polyester, a method of introducing fine powder of metal terephthalate such as calcium terephthalate into the polymer is disclosed in Japanese Patent Publication No. 40-3291 and British Patent No. 1040605.
It is known by the number etc. In these methods of producing calcium terephthalate salts as internal particles, the calcium compound is once dissolved in the polyester reaction system or polyester synthesis raw materials such as glycol, and depending on the state of the system to which it is added, the calcium compound is added immediately or immediately to the system. As the state changes, it gradually precipitates into the system. Therefore, the diameter of the particles obtained is relatively uniform and small, and the affinity for the polyester substrate is sufficient. However, in the case of these calcium terephthalate salt-based internal particles, there are still many coarse particles mixed in, probably due to the strong cohesive force between the particles, and these coarse particles can cause problems such as clogging of filters and tearing of the film during the melt molding process. It was the cause of this. In the above-mentioned Japanese Patent Publication No. 34-5144, it is stated that when a trivalent phosphorus compound is used in combination, the alkaline earth metal salt particles of terephthalic acid actually decrease. This is due to the fact that the internal particles produced by the addition of the phosphorus compound become finer. For this reason, the obtained film has excellent transparency, but has the problem of insufficient slip properties and blocks during the winding process. The purpose of the present invention is to provide polyethylene terephthalate that is ultra-transparent and capable of forming a biaxially oriented film at high speed, which could not be achieved using conventional techniques.
In other words, pinholes occur during high-speed film formation,
To provide polyethylene terephthalate capable of forming a biaxially oriented film, which has no drawbacks such as insufficient adhesion or poor winding properties, has excellent process passability and handleability even in post-processing processes such as metal vapor deposition, and has an excellent appearance as a metal vapor deposited film. It is in. In order to achieve the above object, the present inventors have arrived at the present invention as a result of intensive studies from both the internal particle generation method and the external particle addition method. That is, in the present invention, when producing a polyester from a dicarboxylic acid mainly consisting of an aromatic dicarboxylic acid or an alkyl ester thereof and ethylene glycol, at any point before the start of the polycondensation reaction,
Calcium, magnesium, manganese elements from 1 to 1
at least one compound selected from glycol-soluble calcium compounds, magnesium compounds, and manganese compounds, so as to contain 0.001 to 0.5% by weight of internal particles containing 14% by weight and 0.5 to 10% by weight of elemental phosphorus, and The specific resistance at the time of melting of the polymer obtained by adding a phosphorus compound and further adding 0.01 to 1.0% by weight of silicon dioxide adjusted to pH 7.5 to 10.5 using a basic compound is 5 × 10 ⁸
A method for producing polyester characterized by having a resistance of Ω・cm or less. A feature of the polyethylene terephthalate of the present invention is that it contains a specific amount of internal particles made of a specific element and a specific amount of silicon dioxide treated as inert external particles. The content of internal particles in polyethylene terephthalate is preferably 0.001 to 0.5% by weight (based on the film), more preferably 0.02 to 0.2% by weight. When the internal particle content is less than 0.001% by weight, the coefficient of friction between films and between film and metal becomes large, while when the internal particle content exceeds 0.5% by weight, coarse particles are often generated. This is undesirable because when it is made into a film, its transparency may be impaired, and it may also have an adverse effect on clogging of the filter or tearing of the film during the process of melt-molding the film. Furthermore, the internal particles must contain at least one element selected from calcium element, magnesium element, manganese element and phosphorus element, respectively, 1 to 14% by weight (based on internal particles) and 0.5 to 10% by weight (based on internal particles). It is preferable that it contains (pairs with internal particles). When the content of at least one of calcium, magnesium, and manganese elements in the internal particles is less than 1% by weight, the generated internal particles behave only as oligomers of polyethylene terephthalate, and the external particles of the present invention , it is difficult to develop slipperiness due to the combined use of internal particles. On the other hand, if it exceeds 14% by weight, particles tend to aggregate and coarse particles are likely to be generated. Furthermore, if the phosphorus element content in the internal particles is outside the range of 0.5 to 10% by weight, the fine dispersion effect and transparency effect of the particles due to the internal particle composition unique to the present invention cannot be sufficiently exhibited. That is, if the content of the phosphorus element is less than 0.5% by weight, the generated internal particles tend to be coarse particles, and as the content exceeds 10% by weight, the softening point tends to decrease, making high-speed film formation difficult. The internal particles and external particles contained in the polyethylene terephthalate of the present invention are those separated by the particle separation method described below, and the internal particles are the calcium compounds and magnesium compounds added during the synthesis of the polyethylene terephthalate of the present invention. These particles are produced by combining at least one manganese compound and a phosphorus compound with components constituting polyethylene terephthalate. Note that the internal particles referred to in the present invention may contain trace amounts of other metal components, such as zinc, cobalt, antimony, germanium, titanium, etc., to the extent that the effects of the present invention are not impaired. (Particle separation method) Polyethylene terephthalate film or polyethylene terephthalate film is sufficiently washed with methanol to remove surface deposits, washed with water, and dried. Collect 300 g of the polyethylene terephthalate or film, add 2.7 kg of O-chlorophenol to it, and raise the temperature to 100°C while stirring.
After raising the temperature, the mixture is left to stand for another hour to dissolve the polyethylene terephthalate portion. However, if the polyethylene terephthalate portion does not dissolve, such as when it is highly crystallized, the above-mentioned dissolution operation is performed after melting and quenching. Next, in order to remove coarse insoluble matter other than dust contained in the polyethylene terephthalate or particles of reinforcing agent added, the dissolved solution is separated using a G-1 glass filter, and this weight is subtracted from the sample weight. Rotor in Hitachi Separation Ultracentrifuge Model 40P
Equipped with RP30, after injecting 30 c.c. of the solution after separating the glass filter into each cell, remove the rotor.
Rotate at 4,500 rpm, and after confirming that there are no rotation abnormalities, create a vacuum in the rotor, increase the rotation speed to 30,000 rpm, and perform centrifugal separation of particles at this rotation speed. Separation is completed after approximately 40 minutes, and this can be confirmed, if necessary, by checking that the light transmittance at 375 mμ of the liquid after separation becomes a constant value that is higher than that before separation. After separation, the supernatant liquid is removed by decanting to obtain separated particles. Since the separated particles may be contaminated with polyethylene terephthalate due to insufficient separation, O-chlorophenol at room temperature is added to the collected particles to make them almost uniformly suspended, and then the ultracentrifuge treatment is performed again. . This operation, which will be described later, must be repeated until a melting peak corresponding to the polymer can no longer be detected by drying the particles and subjecting the particles to scanning differential calorimetry. Finally, the thus obtained separated particles are vacuum dried at 120° C. for 16 hours and weighed. Note that the separated particles obtained by the above operation contain both internal particles and external particles. For this reason, it is necessary to determine the amount of internal particles and the amount of external particles separately. First, quantitative analysis of the metal content of the separated particles is performed to determine the content of Ca, Mn, Mg, P, and the content of other metals. I'll keep it. Next, the separated particles are heated under reflux for 6 hours or more in 3 times the molar amount of ethylene glycol, and then the ethylene glycol is distilled off to achieve a temperature of 200° C. or higher for depolymerization, so that only the internal particles are dissolved. The separated particles obtained by centrifuging the remaining particles are dry-weighed to determine the amount of external particles, and the difference from the initial total amount of separated particles is determined to be the amount of internal particles. In order to confirm whether the depolymerization has been completed, the metal content of the separated particles after depolymerization is quantitatively analyzed, and by repeating these operations, the accuracy of particle amount measurement can be improved. The content (addition amount) of inert external particles, that is, silicon dioxide, contained in the polyethylene tereftate of the present invention is 0.01 to 1.0% by weight (based on the polymer)
0.03 to 0.5% by weight to obtain a film with a better balance of transparency and slipperiness.
It is more preferable that If the content of silicon dioxide is less than 0.01% by weight, sufficient slipperiness cannot be obtained, while if it exceeds 1.0% by weight, transparency deteriorates, so that the object of the present invention cannot be achieved. Furthermore, in the present invention, silicon dioxide is made into a slurry dispersed in ethylene glycol and/or water, and the slurry is treated with a basic compound to adjust the pH to 7.5-7.5.
It is necessary to adjust it to a range of 10.5 so that it has a positive charge. If the pH is less than 7.5, coarse particles are generated in the glycol dispersion or during the polycondensation process of polyethylene terephthalate, resulting in decreased transparency and poor appearance of the film after metal deposition. On the other hand, PH is 10.5
If it exceeds this amount, there is a problem that silicon dioxide is solubilized in the glycol dispersion and precipitated as coarse particles during the polycondensation process, and the resulting polyethylene terephthalate has a reduced resistance to hydrolysis. Silicon dioxide in the present invention can be used in both a dry process product obtained by burning silicon halide and a wet process product using sodium silicate as a raw material by adjusting the pH with a basic compound. Generally, the former has a uniform particle size as primary particles of 0.02 to 0.1μ, and has a pH of 3.5 to 4.5. The latter is caused by agglomeration during the drying and pulverizing process, so the average
Although it is a 5μ agglomerate, the pH is 6.5 to 7.5, and the generation of coarse particles due to aggregation is less than that of the former.
By adjusting the pH with a basic compound, it is possible to further improve the dispersibility. The basic compound for adjusting the pH of silicon dioxide may be a hydroxide or carbonate of an alkali metal such as sodium or potassium, but depending on the conditions, silicon dioxide itself may be solubilized, so quaternary ammonium salts, Alternatively, it is preferable to treat with a basic cyclic compound such as morpholine or imidazoline. Note that the PH of silicon dioxide and silicon dioxide adjusted with a basic compound as used in the present invention is measured by the following method. (Method for Measuring PH of Silicon Dioxide) Silicon dioxide is dispersed in ion-exchanged water to form a dispersion liquid with a concentration of 10% by weight, and the PH of the dispersion liquid is measured. (PH of silicon dioxide adjusted with a basic compound) Add an appropriate amount of a basic compound to a 10% concentration dispersion of silicon dioxide in ion-exchanged water, stir well, and then measure the PH. . A further feature of the polyethylene terephthalate of the present invention is that it has a low specific resistance when melted. That is, the specific resistance during melting must be 5×10 ⁸ Ω·cm or less (measured at 3000 VDC). If the melted resistivity exceeds 5×10 ⁸ Ω・cm, the adhesion will decrease.
Problems such as pinholes occur. The specific resistance of molten polyethylene terephthalate is measured using the apparatus shown in FIG. In Figure 1, 1
is a DC high voltage generator, 2 is an ammeter, 3 is a voltmeter,
4 is a heating body, 5 is molten polyethylene terephthalate for measurement, and 6 is a plate-shaped electrode. The specific resistance of molten polyethylene terephthalate was determined by reading the current I when the voltage V was 3000V and using the following formula. Specific resistance R=3000×S/I・(Ω・cm) In the formula, is the distance between the electrodes, and S is the surface area of the electrodes. The biaxially oriented film-forming polyethylene terephthalate of the present invention may be copolymerized with other dicarboxylic acid components, glycol components, and oxycarboxylic acid components within a range not exceeding 20 mol% of the constituent components. A component having three or more functional groups may be copolymerized within a range not exceeding mol%. Furthermore, a monofunctional component may be included in an amount not exceeding 5 mol%. Specific examples of copolymerizable components include the following. Dicarboxylic acid components include adipic acid, sepacic acid, phthalic acid, isophthalic acid, terephthalic acid,
2,6-naphthalene dicarboxylic acid, P,P'-diphenoxyethane dicarboxylic acid, 5-sodium sulfoisophthalic acid, 4,4-benzophenone dicarboxylic acid, etc., and diol acid components include ethylene glycol, diethylene glycol, Propylene glycol, 1,4-butanediol, neopentyl glycol, polyethylene glycol,
Examples include P-xylylene glycol, 1,4-cyclohexanedimethanol, and 5-sodium sulforesorcin. Further, examples of the oxycarboxylic acid component include P-oxyethoxybenzoic acid, and examples of the component having three or more functional groups include trimellitic acid and pyromellitic acid. The biaxially oriented film-forming polyethylene terephthalate of the present invention is produced by a process of polycondensation through direct esterification of terephthalic acid and ethylene glycol, or by a transesterification reaction of a dialkyl ester of terephthalic acid, preferably dimethyl terephthalate, and ethylene glycol. In the process of polycondensation, at least one of glycol-soluble calcium compounds, magnesium compounds, and manganese compounds, a phosphorus ester compound, and silicon dioxide are added in an appropriate manner. The addition of compounds to generate internal particles is
At any time from the time when the esterification reaction or the transesterification reaction is substantially completed to the early stage when the polycondensation reaction has not progressed very much, at least one of a calcium compound, a magnesium compound, a manganese compound and a phosphorus compound are added. Preferably, they are added to the reaction system either separately as a glycol solution or in a mixed state under conditions that they do not react with each other. If the generated internal particles become too fine, use inorganic acids such as phosphorous acid, phosphoric acid, sulfuric acid, nitric acid, phosphinic acid, and phosphonic acid, or organic acids such as acetic acid, benzoic acid, oxalic acid, and terephthalic acid. It is also preferable to control the particle size and amount by adding an appropriate amount of them together. Calcium, magnesium, and manganese compounds that can be used in the present invention include halides,
Inorganic acid salts such as nitrates and sulfates, organic acid salts such as acetates, oxalates, and benzoates, and glycol-soluble compounds such as hydrides and oxides are most preferably used, but two or more types may be used in combination. I don't mind if you do. Phosphorus ester compounds have the general formula O=P(OR ₁ ) _o (OH) _3-o (R ₁ represents a C ₁ to C ₄ alkyl group, phenyl group, or benzyl group, and n is an integer of 1 to 3. Partial esters of phosphoric acid and triesters of phosphoric acid are preferably used. Specific examples of partial esters of phosphoric acid include monomethyl phosphate, dimethyl phosphate, monopropyl phosphate, dipropyl phosphate, etc. Specific examples of triesters of phosphoric acid include trimethyl phosphate,
Examples include triethyl phosphate, tripropyl phosphate, triisopropyl phosphate, triisobutyl phosphate, and triphenyl phosphate. Also general formula (R ₁ and R ₂ are C ₁ to C ₄ alkyl groups, phenyl groups,
Indicates a benzyl group. ) Diesters of phosphonic acid represented by the following formulas, specific examples of which are methylphosphonic acid dimethyl ester, ethylphosphonic acid dimethyl ester, phenylphosphonic acid diethyl ester, and phenylphosphonic acid diphenyl ester, can also be preferably used. On the other hand, when adding silicon dioxide, which is an inert external particle, a slurry in which silicon dioxide is dispersed in water and/or ethylene glycol is treated with a basic compound to adjust the pH to 7.5 to 10.5, and then the polycondensation reaction is performed. Preferably, it is added before or during the reaction. Note that, prior to addition, stirring the slurry at high speed can also be preferably employed as a method for further improving dispersibility. In the present invention, a method in which polyethylene terephthalate containing internal particles and external particles are separately produced and kneaded in a melting process, or a method in which polyethylene terephthalate containing a large amount of internal particles and external particles is diluted is also preferably adopted. Ru. A biaxially oriented polyethylene terephthalate film can be produced from polyethylene terephthalate containing inner particles and outer particles obtained according to the present invention by a known suitable method as shown in FIG. FIG. 2 is a schematic diagram of the biaxial stretching film forming process, where 7 is a die, 8 is a sheet of polyethylene terephthalate, 9 is a DC high pressure generator, 10 is an electrode,
11 indicates a rotary cooling body. In FIG. 2, the sheet-like polyethylene terephthalate 8 extruded from the nozzle 7 is given an electrostatic charge by the electrode 10, brought into close contact with the rotary cooling body 11, and then drawn out in two directions perpendicular to each other. After molecular orientation, crystallization progresses by heating for a necessary period of time, and a stable biaxially stretched polyethylene terephthalate film is wound up. The biaxially oriented polyethylene terephthalate film obtained from polyethylene terephthalate according to the present invention is characterized by a specific amount of uniform fine inner particles made of a specific element and a carbon dioxide treated with a basic compound so as to be positively charged as inert outer particles. This is due to the fact that it contains a specific amount of silicon and has a low specific resistance when melted, and thereby exhibits the following excellent effects. (1) There is less clogging of the filter during the film melt forming process, and there is less tearing of the film membrane due to coarse particles. (2) Even during high-speed film formation, problems such as reduced adhesion and generation of pinholes do not occur, and film products with uniform thickness and uniform surface characteristics can be obtained. (3) Excellent processability and handling properties due to good friction properties. (4) It has excellent transparency and has an excellent appearance after metal deposition. As described above, the biaxially stretched film-forming polyethylene terephthalate of the present invention is an excellent product that has all of the above effects and is completely unknown heretofore. The present invention will be specifically explained below with reference to Examples. In the Examples, the determination of metal elements, determination of phosphorus, film haze, coefficient of friction, etc. were carried out by the following methods. (Quantification of metal elements) Separated particles obtained by the particle separation method described above were
After incinerating by igniting at ℃ for 2 hours, it was measured as a hydrochloric acid solution by atomic absorption spectrometry using a conventional method. (Quantification of elemental phosphorus) A separated particle sample was wet-ashed in the presence of sulfuric acid and perchloric acid, and the ash was colored with ammonium molybdate in an acidic sulfuric acid solution, and the absorbance at a wavelength of 845 mμ was measured. Quantitate using the prepared calibration curve. (Observation of particles in chips) 1 mg of chips was sandwiched between two cover glasses.
Melt at 280℃, form a thin film, then rapidly cool and observe with a microscope. (Method for Measuring Film Haze) Film haze was measured in accordance with ASTM-D-1003-52. (Method for determining appearance of metallized film) One side of the film is subjected to aluminum metallization, and the appearance of the obtained metallized film is observed with the naked eye. Items that could not be seen above were evaluated as ◎. (Method for measuring the coefficient of friction of a film) Using a slip tester manufactured by Toyo Tester,
Measured according to ASTM-D-1894B method. The coefficient of static friction was used as a measure of the slipperiness of the film. (Film forming property) A biaxially stretched film with a thickness of 12μ is formed at a speed of 130 m/min, and there is no tearing during 24 hours.
Tests performed 1 to 2 times were evaluated as ○, and tests performed 3 times or more were evaluated as ×. Example 1 87 parts by weight of terephthalic acid, 42 parts by weight of ethylene glycol
Parts by weight were placed in an autoclave, and a direct esterification reaction was carried out at 220° C. and a pressure of 1.5 kg/cm ² without adding a catalyst. The distilled water is continuously distilled out of the system, and when the reaction rate of the system reaches 50%, the pressure inside the system begins to be released, and finally the pressure is reduced to 245°C under normal pressure, and esterification begins. The reaction has ended. Next, dry process silicon dioxide was dispersed in a mixed solution of ethylene glycol and water to form a slurry, and tetraethylammonium hydroxide was added to adjust the pH, and the slurry was added to the esterification reaction product. Furthermore, after adding 0.06 parts by weight of magnesium acetate tetrahydrate, 0.03 parts by weight of antimony trioxide, and 0.025 parts by weight of trimethyl phosphate, polycondensation was carried out by a conventional method to prepare silicon dioxide as shown in Table 1. Various polyethylene terephthalates (intrinsic viscosity 0.625) with different pH and addition amount were obtained. Next, each polyethylene terephthalate was subjected to a biaxial stretching film forming process as shown in Figure 2, at a high voltage casting speed of 20 m/min to 5 m/min.
When the film forming properties were evaluated by increasing the casting speed by min increments, the upper limit of the high voltage casting speed at which pin-like defects did not occur was 45 m/min in each case, indicating excellent high-speed film forming properties. In addition, Table 1 shows the properties of biaxially stretched polyethylene terephthalate films obtained by forming films from each of the obtained polyethylene terephthalates at a high voltage casting speed of 40 m/min, a longitudinal stretching ratio of 3.2, and a winding speed of 130 m/min. Indicated. Film forming conditions other than those described above are as follows. (Film forming conditions) Film thickness: 12μ (after biaxial stretching) Extrusion temperature: 285℃ Casting: High voltage electrostatic application cast Lateral stretching ratio: 3.6x Heat treatment temperature: 225℃

[Table] In Table 1, experiment numbers 1, 5, 6, and 9 are comparative experiments to clarify the effects of the present invention.
Experiment No. 1 had poor slipperiness due to the small amount of silicon dioxide added, while Experiment No. 5 had a large film haze due to the large amount of silicon dioxide added, resulting in poor transparency and poor appearance of the deposited film. has worsened. Further, in Experiment No. 6, since the pH of silicon dioxide was 11, the haze of the film was large due to coarse particles caused by aggregation, and the appearance of the deposited film deteriorated. In Experiment No. 9, the pH was 6.5, so the dispersibility was insufficient, the transparency decreased, and the appearance of the deposited film deteriorated. Example 2 The esterification reaction was completed in the same manner as in Example 1, and then a slurry was prepared by dispersing dry silicon dioxide in a mixed solution of ethylene glycol and water,
Tetraethylammonium hydroxide was added to the slurry to adjust the pH to 9, and 0.1% by weight of the slurry was added to the esterification reaction product. Further, 0.03 parts by weight of antimony trioxide, calcium acetate monohydrate, and trimethyl phosphate were added in various amounts as shown in Table 2, and polycondensation and film formation were carried out in the same manner as in Example 1. A biaxially stretched polyethylene terephthalate film was obtained. The evaluation results of the obtained film are shown in Table 2.

【table】

[Table] Experiment numbers 11, 15, and 20 in Table 2 are comparative experiments to clarify the effects of the present invention. , the appearance of the vapor-deposited film was poor. In Experiment No. 15, the content of internal particles was too large, resulting in large film haze and poor appearance of the deposited film. In addition, in experiment number 20, the resistivity during melting was high, resulting in poor film forming properties and frequent film tearing. Example 3 The esterification reaction was completed in the same manner as in Example 1, and then wet silicon dioxide was dispersed in a mixed solution of ethylene glycol and water to form a slurry,
Tetraethylammonium hydroxide was added to the slurry to adjust the pH to 10.0, and 0.1% by weight of the slurry was added to the esterification reaction product. Additionally, 0.03 parts by weight of antimony trioxide, 0.0792 parts by weight of calcium acetate monohydrate, and trimethyl phosphate.
After adding 0.0402 parts by weight, polycondensation and film formation were carried out in the same manner as in Example 1 to obtain a biaxially stretched polyethylene terephthalate film. The melting specific resistance of the obtained film was 1.2×10 ⁸ Ω·cm, and the appearance of the metal-deposited film was also good (rated ◎). Comparative Example 1 The esterification reaction was completed in the same manner as in Example 1, and then wet method silicon dioxide of PH 6.5 was made into a slurry dispersed in a mixed solution of ethylene glycol and water, and 0.05 weight of the esterified product was added. % added. Furthermore, 0.03 parts by weight of antimony trioxide, 0.06 parts by weight of magnesium acetate tetrahydrate, and 0.025 parts by weight of trimethyl phosphate were added, and polycondensation and film formation were carried out in the same manner as in Example 1 to obtain a biaxially oriented polyethylene terephthalate film. Ta. The appearance of the metal-deposited film using the obtained film was not desirable. (Judgment △) Comparative Example Example 2 The esterification reaction was completed in the same manner as in Example 1, and then commercially available kaolinite was dispersed in a mixed solution of ethylene glycol and water to a concentration of 100 g/
The kaolinite-ethylene glycol/water slurry was adjusted so that Add 1.0% by weight of tetraethylammonium hydroxide based on kaolinite to this slurry, stir the slurry thoroughly, and then add it to the esterification reaction product so that the concentration of kaolinite in the polymer is 0.3% by weight. Polycondensation and film formation were carried out in the same manner as in Example 1 to obtain a biaxially stretched polyethylene terephthalate film. The static friction coefficient of the obtained film was 0.7,
The haze of the film was 9.0%, and the slip properties were good, but the appearance of the metal-deposited film using the obtained film was poor dispersion of kaolinite,
This was not preferable because the film haze was high due to the inclusion of coarse particles. (Judgment ×) Comparative Example Example 3 The esterification reaction was completed in the same manner as in Example 1, and then a slurry was prepared by dispersing commercially available kaolinite in a mixed solution of ethylene glycol and water.
Kaolinite of 5 microns or less was obtained by the sedimentation method, and a slurry of kaolinite ethylene glycol/water was adjusted to a concentration of 100 g/ml. Tetraethylammonium hydroxide was added to this slurry in an amount of 1.0% by weight based on kaolinite.
After sufficiently stirring the slurry, polycondensation and film formation were carried out in the same manner as in Example 1, except that kaolinite was added to the esterification reaction product so that the concentration of kaolinite in the polymer was 0.3% by weight. Obtained terephthalate film. The coefficient of static friction of the obtained film was 0.75, the haze of the film was 8.0%, and the slip property was good. However, the appearance of the metal-deposited film using the obtained film was due to poor dispersion of kaolinite. This was not desirable because of the high haze. (Judgment ×) Comparative Example 4 The esterification reaction was completed in the same manner as in Example 1, and then the slurry of kaolinite obtained by adjusting in the same manner as in Comparative Example 3 was adjusted to a concentration of kaolinite. A biaxially stretched polyethylene terephthalate film was obtained by polycondensation and film formation in the same manner as in Example 1, except that it was added to the esterification reaction product at a concentration of 0.05% by weight. The obtained film had a coefficient of static friction of 2.8, a haze of 1.5%, and had poor slip properties.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an apparatus for measuring the melting specific resistance of polyethylene terephthalate, and FIG. 2 is a schematic diagram of a biaxial stretching film forming process. 1, 9: DC high pressure generator, 4: Heating body, 5:
Polyethylene terephthalate for measurement, 6,10:
Electrode, 7: Base, 8: Sheet polyethylene terephthalate, 11: Rotating cooling body.

Claims (1)

[Claims] 1. When producing polyester from dicarboxylic acid mainly consisting of aromatic dicarboxylic acid or its alkyl ester and ethylene glycol, calcium, magnesium, and manganese elements are added in an amount of 1 to 14% by weight at any time before the start of the polycondensation reaction. , and internal particles containing 0.5-10% by weight of elemental phosphorus
At least one compound selected from glycol-soluble calcium compounds, magnesium compounds, and manganese compounds and a phosphorus compound are added so that the content is 0.001 to 0.5% by weight, and a basic compound is used to adjust the pH to 7.5 to 10.5. 1. A method for producing polyester, characterized in that the specific resistance of a polymer obtained by adding 0.01 to 1.0% by weight of silicon dioxide adjusted to 0.01 to 1.0% by weight has a specific resistance of 5×10 ⁸ Ω·cm or less when melted.