JPH039126B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a polyester whose main repeating unit is ethylene terephthalate, which has good resin quality, easy brand switching, and improved transparency and electrostatic adhesion. It is something. Saturated linear polyester, represented by polyethylene terephthalate, has excellent mechanical properties, heat resistance, weather resistance, electrical insulation, and chemical resistance, so it is used in a wide range of fields such as packaging, electrical applications, and magnetic tape. has been done. Polyester films are usually obtained by melt-extruding polyester and then biaxially stretching it. In this case, in order to increase the uniformity of the film thickness and the speed of casting, when the sheet material melted and extruded from the extrusion die is rapidly cooled on the surface of the rotating cooling drum, the adhesion between the sheet material and the drum surface is increased. There must be. As a method of increasing the adhesion between the sheet-like material and the drum surface, a wire-shaped electrode is installed between the extrusion die and the rotating cooling drum, and a high voltage is applied to deposit static electricity on the top surface of the unsolidified sheet-like material. It is known that a method of rapidly cooling the sheet-like material while bringing it into close contact with the surface of the cooling body (hereinafter referred to as electrostatic adhesion casting method) is effective. Uniformity of film thickness is a very important property in film quality, and film productivity is directly dependent on casting speed, so increasing the casting speed is extremely important to improve productivity. Therefore, great efforts are being made to improve electrostatic adhesion. An effective means of achieving such electrostatic adhesion is to increase the amount of charge on the surface of the sheet-like object. Therefore, in order to increase the amount of charge on the surface of the sheet-like object in the electrostatic adhesion casting method, polyester raw material It is known that it is possible to lower the resistivity by modifying the Furthermore, as a method of lowering the specific resistance of this polyester raw material, it is known to add an alkali metal or alkaline earth metal compound after the completion of the esterification or transesterification reaction. It is true that this method lowers the specific resistance of the polyester raw material and the electrostatic adhesion reaches a somewhat satisfactory level, but in the manufacturing process of the polyester raw material, in order to increase the electrostatic adhesion, the esterification rate must be significantly increased. To achieve this, a large amount of ethylene glycol (hereinafter referred to as EG) must be used, and the reaction time becomes longer, which inevitably increases the amount of diethylene glycol (hereinafter referred to as DEG) as a by-product, which is a serious drawback. are doing. This by-product DEG
An increase in the amount of polyester lowers the softening point of the polyester, so the film tends to become viscous on the surface of the rotating cooling drum during film formation, and the film tends to tear more often during stretching, furthermore, the heat resistance of the obtained film decreases. It may cause such things as Furthermore, when the above method is carried out continuously, it has the disadvantage that it cannot easily cope with changing brands or increasing the number of brands. The present inventors improved the above-mentioned conventional drawbacks,
The amount of DEG by-product is small, and brand switching is easy.
As a result of intensive research into a method for manufacturing polyester that also has excellent transparency and electrostatic adhesion,
This has led to the present invention. In the present invention, when producing a polyester whose main repeating unit is ethylene terephthalate, the following master polymer or/and master polymer is converted into Ca atoms at a stage after the initial condensation reaction is completed and the intrinsic viscosity reaches 0.2 or more. This is a method for producing polyester, characterized in that the polyester is added in such a manner that: 0.1≦Ca≦3.0〓 ...() 1.2≦Ca/P≦3.0 ...() (wherein, Ca is the weight% of the master polymer as a Ca atom in the added Ca compound,
Ca/P indicates the atomic ratio of Ca metal atoms to phosphorus atoms. ) Master polymer: A Ca compound that simultaneously satisfies the above general formulas () and () when a dicarboxylic acid, mainly terephthalic acid, and a glycol, mainly ethylene glycol, are reacted and the esterification rate has progressed to 91% or more. and a polymer with an intrinsic viscosity of 0.2 or more prepared by adding a P compound and then polycondensing it. Master polymer: An acid component mainly consisting of a lower alkyl ester of terephthalic acid and a glycol component mainly consisting of ethylene glycol are reacted, and when the transesterification reaction is substantially completed, the above general formulas () and () are simultaneously combined. The intrinsic viscosity prepared by adding a satisfactory amount of Ca compound and P compound and then polycondensing
Polymer over 0.2. Here, the intrinsic viscosity is a value measured at 30° C. by dissolving a polymer, master polymer, or oligomer in a mixed solvent of phenol (6 parts by weight) and tetrachloroethane (4 parts by weight). The definition of polyester "relative to polyester" here is a theoretical value calculated from the amount of dicarboxylic acid that passes through, mainly consisting of TPA, and is calculated assuming that dicarboxylic acid mainly consisting of TPA becomes 100 mol% polyester. . In the polyester finally obtained in the present invention, 80 mol% or more of its repeating units consist of ethylene terephthalate, and other copolymer components include isophthalic acid, p-β-oxyethoxybenzoic acid, and 2,6-naphthalene dicarboxylic acid. acid,
Dicarboxylic acids and their derivatives such as 4.4'-dicarboxyldiphenyl, 4.4'-dicarboxylbenzophenone, bis(4-carboxylphenyl)ethane, adipic acid, sebacic acid, and 5-sodium sulfoisophthalic acid are listed. It will be done. In addition, glycol components include propylene glycol, butanediol, neopentyl glycol,
Cyclohexane dimethanol, bisphenol A
Ethylene oxide adducts and the like can be arbitrarily selected and used. In addition, small amounts of amide bonds, urethane bonds, ether bonds, carbonate bonds, etc. may be included as copolymer components. Such polyesters are produced by conventional melt polymerization methods. For example, either a direct polymerization method or a transesterification method may be employed, and either a batch method or a continuous method may be employed. The transesterification and polycondensation catalysts can be appropriately selected from conventionally known catalysts, and it goes without saying that lubricants made of inorganic or organic fine particles and various other additives may also be used. A major feature of the present invention is that a pre-prepared master polymer is added at a stage after the completion of the initial condensation reaction in an amount of 50 to 400 ppm as calcium metal atoms based on the total polyester. The master polymer is preferably added to the reaction system after the initial condensation reaction has been completed and its intrinsic viscosity has reached 0.2 or higher. If the master polymer is added when the intrinsic viscosity is less than 0.2, the mixing of the master polymer will be incomplete, making it difficult to realize the effects of the polymer blending method, and depolymerization of the master polymer will occur, which is economically disadvantageous. This is not desirable. It is more preferable that the difference between the above-mentioned intrinsic viscosity and the intrinsic viscosity of the master polymer to be added be as small as possible, since this will allow complete mixing and the effects of the polymer blending method will be more easily exhibited. The master polymer may be prepared by either a direct polymerization method or a transesterification method. Esterification rate is 91% when prepared by direct polymerization method
When the above has progressed, or when the transesterification reaction is substantially completed in the case of preparation by the transesterification method, an amount of calcium compound and phosphorus compound that simultaneously satisfies the following general formula is added, followed by polycondensation. This is done by 0.5≦Ca≦3.0 …() 1.2≦Ca/P≦3.0 …() (In the formula, Ca is the amount of polyester calculated assuming that the dicarboxylic acid component as calcium metal atoms in the added calcium compound becomes 100% polyester. (wt%, Ca/P indicates the atomic ratio of calcium metal atoms to phosphorus atoms) If a calcium compound is added before the esterification rate is less than 91% or before the transesterification reaction is substantially completed, the ratio of the polyester raw material This is not preferable because the resistance decreases little, and as a result, the electrostatic adhesion is insufficiently improved, and coarse particles due to calcium compounds are often deposited, resulting in a decrease in the transparency of the film. Furthermore, when preparing by the transesterification method, it is not preferable to add a calcium compound before the transesterification reaction is substantially completed because it becomes difficult to control the transesterification reaction. The amount of calcium compound added when preparing the master polymer is calculated based on the assumption that the dicarboxylic acid component becomes 100% polyester as calcium metal atoms. If it is less than 0.5% by weight of the polyester produced, the amount of master polymer used will be large, so it is economical. On the other hand, if it exceeds 3.0% by weight, the amount of DEG by-products and the amount of coarse particles precipitated due to calcium compounds will increase, which is not preferable. Especially 1-2
It is more preferable to add % by weight. Also, the ratio of calcium compounds and phosphorus compounds to be added is Ca/
If P is less than 1.2, the specific resistance of the polyester raw material decreases little, resulting in insufficient improvement in electrostatic adhesion, which is not preferable. On the other hand, if it exceeds 3.0,
This is not preferable because the precipitation of coarse particles due to calcium compounds increases and the transparency of the film decreases. In particular, the range of 1.4 to 2.0 is more preferable. The calcium compound used in preparing the master polymer is not particularly limited as long as it is soluble in the reaction system, such as calcium hydride, calcium oxide, lower fatty acid salts such as calcium acetate, and alkoxides such as calcium methoxide. etc. can be mentioned. In addition, as a phosphorus compound,
Examples include phosphoric acid, phosphorous acid, phosphonic acid, and derivatives thereof. Specific examples include phosphoric acid, trimethyl phosphate, triethyl phosphate, tributyl phosphate, triphenyl phosphate, and monomethyl phosphate. , phosphoric acid dimethyl ester, phosphoric acid monoethyl ester, phosphoric acid diethyl ester, phosphoric acid monobutyl ester, phosphoric acid dibutyl ester, phosphorous acid,
Phosphite trimethyl ester, phosphite triethyl ester, methylphosphonic acid, methylphosphonic acid dimethyl ester, ethylphosphonic acid dimethyl ester, phenylphosphonic acid diphenyl ester, etc. These may be used alone, or two or more types may be used. May be used together. The calcium compound and the phosphorus compound may be added at the same time or separately, but adding the calcium compound after the phosphorus compound reduces the precipitation of coarse particles caused by the calcium compound. More preferable in meaning. The master polymer may have any composition as long as it satisfies the above requirements. For example, the molecular weight of the master polymer is not particularly limited as long as its intrinsic viscosity is 0.2 or more. However, in order to exhibit the effect of the polymer blending method in the method of the present invention, it is preferable that the intrinsic viscosity be as close as possible to that of the base resin. In addition, terephthalic acid, dicarboxylic acids other than EG, and glycol may be used as copolymerization components as long as they are 20 mol % or less. In the present invention, the amount of master polymer added to the reaction system is within the range of 50 to 400 ppm as calcium metal atoms based on the total polyester. If it is less than 50 ppm, the specific resistance of the polyester raw material decreases little, resulting in insufficient improvement in electrostatic adhesion, which is not preferable. On the other hand, if it exceeds 400 ppm, the decrease in the resistance of the polyester raw material reaches a plateau, and the precipitation of coarse particles due to calcium compounds increases, resulting in a decrease in the transparency of the film, which is not preferable. Furthermore, it causes quality deterioration such as an increase in the amount of DEG by-products and a decrease in the stability of polyester. In addition, the supply of master polymer to the reaction system is as follows:
It may be carried out either in the form of chips or in a molten state, but it is preferable to carry out the process in a molten state from the viewpoint of feeding accuracy and ease of mixing. Further, it is preferable to use a mixing and kneading device to blend a master polymer with an intrinsic viscosity exceeding 0.5. Especially JP-A-56-44031, JP-A-56-
44032, patent application No. 10635 and application No. 57-57772
Most preferably, an apparatus such as that described in . Next, Examples and Comparative Examples of the present invention will be shown. All parts in the examples mean parts by weight unless otherwise specified. In addition, the measurement method used is shown below. (1) Esterification reaction rate Calculated from the amount of carboxyl groups remaining in the reaction product and the saponification value of the reaction product. (2) Intrinsic viscosity Dissolve the polymer master polymer or oligomer in a mixed solvent of phenol (6 parts by weight) and tetrachloroethane (4 parts by weight) and measure at 30°C. (3) Amount of DEG in the polymer The polymer is decomposed with methanol and measured as mol% relative to EG by gas chromatography. (4) Number of coarse particles in the polymer A small amount of polymer is sandwiched between two cover glasses, melt-pressed at 280℃, rapidly cooled, observed using a phase contrast microscope, and the number of particles counted using an image analyzer. do. (5) Melting specific resistance of polymer Place two electrode plates in polyester melted at 275℃, measure the current value (jo) when applying a voltage of 120V, and calculate the specific resistance value (qj) using the following formula. Find it by qj (Ω・cm)=A/l×V/jo A=electrode area (cm ² ), l=interelectrode distance (cm), V=voltage (V) (6) Electrostatic adhesion Extruder mouthpiece A tungsten wire electrode was installed between the casting drum and the casting drum, and a voltage of 10 to 15 KV was applied between the electrode and the casting drum to perform casting, and the surface of the resulting casting material was observed with the naked eye. , the casting speed at which pinner bubbles begin to occur is evaluated. The higher the casting speed of the polymer, the better the electrostatic adhesion. (7) Film haze Measure with a direct reading haze meter (manufactured by Toyo Seiki Co., Ltd.). Example 1 (1) Preparation of master polymer 519 parts of terephthalic acid, 431 parts of EG, 0.16 parts of triethylamine, and 0.23 parts of antimony trioxide were charged into a stainless steel autoclave equipped with a stirrer, a distillation column, and a pressure regulator, and the mixture was purged with nitrogen and then added. The esterification reaction was carried out while maintaining the pressure at a gauge pressure of 2.5 kg/cm ² at 250° C. and continuously removing water produced from the top of the distillation column. After 100 minutes had passed from the start of the reaction, the pressure was released to obtain a product with an esterification rate of 98%. The intrinsic viscosity of the ester product is
It was less than 0.1. 15.7 parts of trimethyl phosphate was added to this esterification product, and
The mixture is heated and stirred at 240°C for 10 minutes, and then a slurry of 31.5 parts of calcium acetate hydrate dispersed in 210 parts of EG is added, and the mixture is heated at the same temperature under normal pressure for 15 minutes. While raising the reaction temperature to 280°C, the pressure of the reaction system was gradually lowered to 0.05 mmHg.
A polycondensation reaction was carried out at 280°C and 0.05 mmHg for about 60 minutes to obtain a master polymer with an intrinsic viscosity of 0.321. The calcium metal atoms in the obtained master polymer were 1.2% by weight, and Ca/P was
It was 1.6. (2) Polymer production Using a continuous esterification reactor consisting of a two-stage complete mixing tank equipped with a stirrer, a partial condenser, a raw material inlet, and a product outlet, esterification is carried out in the first esterification reactor. The molar ratio of EG to terephthalic acid was adjusted to 1.7, and antimony trioxide was added as an antimony metal atom to the system containing the reaction product, at 289 ppm per terephthalic acid unit.
EG slurry of terephthalic acid was continuously fed. Average residence time 4.5 hours at normal pressure,
The reaction was carried out at a temperature of 255°C. This reaction product was continuously taken out of the system and supplied to the second esterification reactor. Furthermore, 0.5 per polyester is calculated assuming that EG is added and the dicarboxylic acid component becomes 100% polyester.
Continuously add parts by weight, average residence time at normal pressure
The reaction was carried out for 5.0 hours at a temperature of 260°C. The esterification rate of the first esterification reactor is 70%, and the esterification rate of the reaction product in the second esterification reactor is 98%.
It was hot. The esterification reaction product is continuously filtered through a stainless steel wire mesh filter with an opening of 600 mesh, and the first stage polycondensation reaction apparatus is equipped with a stirrer, a partial condenser, a raw material inlet, and a product outlet. Continuously supplied to perform a polycondensation reaction, resulting in an intrinsic viscosity of 0.320
of polymer was obtained. This polymer is continuously taken out, using a stirring device,
Continuously supplied to a second stage polycondensation reactor equipped with a decondenser, a raw material inlet and a product outlet,
In the method of completing the polycondensation reaction, a line mixer is provided in the middle of the piping connecting the first and second stage polycondensation reactors, and the master polymer prepared in advance by the above method is passed through the piping to this line mixer. The polymer was continuously fed in a molten state at a ratio of 1.67 parts to 100 parts of the polymer (200 ppm as calcium metal atoms per polyester), and finally a polymer with an intrinsic viscosity of 0.620 was obtained.
The quality of this polymer was obtained by melt extruding the polymer at 290°C, stretching it 3.5 times in the longitudinal direction at 90°C, stretching 3.5 times in the transverse direction at 130°C, and then heat-treating it at 220°C.
Table 1 shows the film haze of the 12μ film. As is clear from Table 1, the polyester obtained by the method of the present invention has good electrostatic adhesion, transparency, coarse particles,
It can be seen that the DEG contents were all good and the quality was good. Comparative Example 1 In the method of Example 1-(2), except that the master polymer was not supplied all at once to the line mixer,
Table 1 shows the quality and film haze of the polymer obtained by the same method as in Example 1-(2). It can be seen that although the method of this comparative example has good transparency, large particles, and DEG content, the electrostatic adhesion is extremely poor. Comparative Example 2 In the method of Example 1-(2), calcium acetate monohydrate and trimethyl phosphate were used instead of the master polymer fed to the line mixer.
Example 1-( Table 1 shows the quality and film haze of the polymer obtained by the same method as 2). Among the qualities of the polyester obtained by the method of this comparative example, the electrostatic adhesion and transparency are relatively good, but the DEG content is high. Also, with this method,
The addition of EG solution causes depolymerization of the prepolymer, which reduces the productivity of the polymerization and reduces the intrinsic viscosity.
In order to obtain a polymer of 0.620, the polycondensation temperature must be higher than in the method of Example 1-(2),
It is also inferior in that it is economically disadvantageous. Example 2 (1) Preparation of master polymer In a polymerization reactor, 607 parts of dimethyl terephthalate,
486 parts of EG and 0.31 parts of magnesium acetate tetrahydrate were charged, and transesterification was carried out by heating at 195° C. for about 4 hours in a nitrogen atmosphere. As the transesterification reaction progressed, the reaction temperature rose to reach a final temperature of 240°C, substantially completing the transesterification reaction. This reaction product contains trimethyl phosphate.
Add 15.7 parts of calcium acetate and stir at normal pressure for 10 minutes at 240℃, then add 31.5 parts of calcium acetate hydrate.
Add the slurry liquid dispersed in 210 parts of EG, heat at the same temperature under normal pressure for 15 minutes, and add 12 g/l.
19.22 parts by volume of an EG solution of antimony trioxide at a concentration of . While raising the reaction temperature to 280°C, the pressure in the reaction system was gradually lowered to 0.05mmHg, and the polycondensation reaction was carried out at 280°C and 0.05mmHg for about 60 minutes to obtain a master polymer with an intrinsic viscosity of 0.315. The calcium metal atoms in the obtained master polymer were 1.2% by weight, and Ca/
p was 1.6. (2) Production of polymer In the method of Example 1-(2), the master polymer supplied to the line mixer was changed to the method of Example 2-(1).
Table 1 shows the quality and film health of the polymer obtained by the same method as in Example 1-(2) except that the master polymer prepared by the method described above was used. It can be seen that the obtained polymer and film are of high quality. Example 3 (1) Preparation of master polymer Example 1 except that the polycondensation time was about 120 minutes
-A master polymer with an intrinsic viscosity of 0.512 was obtained using the same method as in (2). (2) Production of polymer Example 1-
A polymer with an intrinsic viscosity of 0.620 was obtained using the same method as in (2). This polymer was continuously taken out and continuously supplied to a mixing and kneading device installed after the second stage polycondensation reaction device, and at the same time, the polymer was prepared in advance by the method of Example 3-(1). A blended polymer was obtained by continuously supplying the blended polymer in a molten state at a ratio of 1.67 parts to 100 parts of the polymer passing through the master polymer (200 ppm added as calcium metal atoms to the polyester). Table 1 shows the quality of this blend polymer and the film health of the film obtained by forming the blend polymer in the same manner as in Example 1-(2). 【table】

Claims (1)

[Claims] 1. When producing a polyester whose main repeating unit is ethylene terephthalate, the following master polymer or/and master polymer is used at a stage after the initial condensation reaction has completed and the intrinsic viscosity has reached 0.2 or more. A method for producing polyester, characterized in that Ca atoms are added in an amount of 50 to 400 ppm based on the total polyester. 0.1≦Ca≦3.0...() 1.2≦Ca/P≦3.0...() (In the formula, Ca is the weight% of the master polymer as Ca atoms in the added Ca compound,
Ca/P indicates the atomic ratio of Ca metal atoms to phosphorus atoms. ) Master polymer: A Ca compound that simultaneously satisfies the above general formulas () and () when dicarboxylic acid, mainly terephthalic acid, and glycol, mainly ethylene glycol, are reacted and the esterification rate has progressed to 91% or more. and a polymer with an intrinsic viscosity of 0.2 or more prepared by adding a P compound and then polycondensing it. Master polymer: An acid component mainly consisting of a lower alkyl ester of terephthalic acid and a glycol component mainly consisting of ethylene glycol are reacted, and when the transesterification reaction is substantially completed, the above general formulas () and () are simultaneously combined. The intrinsic viscosity prepared by adding a satisfactory amount of Ca compound and P compound and then polycondensing
Polymer over 0.2.