JPS6328450B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a polyester-polyether copolymer, and more specifically to a method for producing a degraded polymer,
The present invention relates to a method for producing a polyester-polyether copolymer with good quality and less foreign matter in the polymer due to carbides. Polyester-polyether copolymers, which have an aromatic polyester component as a hard segment and a polyalkylene glycol component as a soft segment, have recently been in the spotlight as a new thermoplastic elastomer that can replace conventional natural rubber and synthetic rubber. Since such polyester-polyether copolymers soften at relatively low temperatures and exhibit good fluidity,
It can be economically molded using conventional thermoplastic molding methods (e.g., injection molding and extrusion molding), and at the same time has many features such as excellent rubber elasticity, easy adhesion, and chemical resistance. For this reason, Tube,
It is expected to have a wide range of uses as hoses, belts, tires, films, and elastic threads. The above-mentioned polyester-polyether copolymer can be produced by two methods: a so-called direct polymerization method in which aromatic dicarboxylic acid, glycol, and polyalkylene glycol components are first subjected to an esterification reaction, and then polycondensed; A so-called transesterification polymerization method is well known in which glycol and polyalkylene glycol components are first subjected to an esterification reaction and then polycondensed. Batch and continuous processes are generally used for these manufacturing processes, but a wide variety of methods can be used by changing the copolymer components or the composition of the hard and soft segments of the polyester-polyether copolymer. The batch method is more flexible than the continuous method because stabilizers, nucleating agents, thickeners, etc. are often added to the polymerization can. There is. However, during the manufacturing process, polyester-polyether copolymers have poor melting heat resistance, especially in an oxygen-containing atmosphere, compared to homopolymers such as polyethylene terephthalate or polybutylene terephthalate, and the batch polymerization method When manufacturing composites, the adhered polymer undergoes thermal deterioration in the polymer discharge circuit from the polymer discharge valve to the discharge nozzle, producing carbonized matter, which peels off and mixes into the polymer as foreign matter, resulting in the formation of polyester. - There was a drawback that the quality of polyether deteriorated. The present inventors have conducted intensive studies to prevent the generation of carbonized foreign matter around the discharge portion, which is a drawback of the batch polymerization method, and have discovered the present invention. That is, an object of the present invention is to provide a method for producing a polyester-polyether copolymer that prevents the generation of carbonized foreign matter around the discharge portion during batch polymerization. The purpose of the present invention is to provide a method for producing a polyester-polyether copolymer containing aromatic dicarboxylic acid or its ester-forming derivative, 1,4-butanediol, and polyalkylene glycol by batch polymerization. , from the end of dispensing the batch to the start of dispensing the next batch, the polymer dispensing circuit from the dispensing valve to the dispensing nozzle is filled with the polymer produced in the previous batch, and the polymer discharging circuit This can be achieved by a method for producing a polyester-polyether copolymer, which is characterized in that the temperature of the jacket part heated is maintained at 250 DEG C. or lower. As the dicarboxylic acid component constituting the polyester-polyether copolymer of the present invention, an aromatic dicarboxylic acid or an ester-forming derivative thereof is used.
Among dicarboxylic acid components containing mol% or more, aromatic dicarboxylic acid components include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 1,
2-bis(phenoxy)ethane P,P'-dicarboxylic acid, diphenyl P,P'-dicarboxylic acid, etc. or ester-forming derivatives thereof are used, and terephthalic acid, isophthalic acid, and mixtures thereof are particularly preferably used. . Furthermore, succinic acid,
It is also possible to use less than 50 mol% of aliphatic dicarboxylic acids or alicyclic dicarboxylic acids such as adipic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, or ester-forming derivatives thereof. The glycol components constituting the polyester-polyether copolymer of the present invention include glycols containing at least 70 mol% of 1,4-butanediol and having a molecular weight of less than 250, such as ethylene glycol, 1,3-propanediol, , 1,6-
Mention may be made of glycols containing less than 30 mol % of primary diol compounds such as hexanediol, diethylene glycol, triethylene glycol, 1,4-cyclohexanedimethanol. In addition to the above-mentioned dicarboxylic acid component and glycol component, copolymerization components include oxycarboxylic acids such as P-(β-hydroxyethoxy)benzoic acid and P-oxymethylbenzoic acid, and trifunctional or higher functional acids such as trimellitic acid, trimesic acid, and pyromellitic acid. It is also possible to use a small amount of polyhydric carboxylic acid. The polyalkylene glycol component constituting the polyester-polyether copolymer of the present invention includes polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and copolymers thereof, and in particular, polytetramethylene glycol and tetramethylene oxide units. A polyalkylene glycol copolymer containing as a main component is preferably used. The number average molecular weight of polyalkylene glycol is preferably 400 to 6000,
If the average molecular weight is less than 400, the blockness of the resulting polyester-polyether copolymer will decrease, and the melting point of the polymer will become low, which is not preferable. If the molecular weight of the polyalkylene glycol is 6,000 or more, the resulting polymer tends to undergo phase separation and become opaque, which is undesirable. The weight percent of the repeating unit consisting of a polyalkylene glycol component and a dicarboxylic acid component, that is, the soft segment unit, of the polyester-polyether copolymer can be appropriately selected depending on the elastic properties required for the polyester-polyether copolymer. However, it is generally about 10 to 80% by weight,
Particularly preferred is about 15 to 70% by weight. Although the present invention is applicable to both the direct polymerization method and the transesterification polymerization method, a more detailed explanation will be given below based on embodiments of the present invention, taking the direct polymerization method as an example. A dicarboxylic acid whose main component is aromatic dicarboxylic acid, a glycol with a molecular weight of less than 250 whose main component is 1,4-butanediol, and a molecular weight of 400 to 6,000 in an esterification reactor equipped with a stirrer and a rectification column.
A polyalkylene glycol and an esterification catalyst are charged and an esterification reaction is carried out. The esterification reaction is usually performed at around 150℃ to 220-240℃ under normal pressure.
The temperature is gradually raised to 100%, and water and tetrahydrofuran produced are distilled off through a rectification column. The esterification reaction time depends on the raw material composition of the reaction system,
Although it is affected by the catalyst species, catalyst amount, reaction temperature, etc., it is generally about 2 to 7 hours. After the esterification reaction is completed, a polycondensation catalyst, etc. is added, and then the reactants are transferred to a polycondensation reactor (polymerization can) and heated to 1 mmHg.
Polycondensation was carried out at 230 to 260°C under the following high vacuum for several hours, and after confirming that the desired degree of polymerization had been reached using the power load of the stirrer, the inside of the polymerization vessel was broken with N ₂ and the vacuum was broken.
Apply _N2 pressure, open the discharge valve, cool the polymer discharged from the mouthpiece, and cut it into chips. In the process of repeated manufacturing using the above method, the polymer discharge circuit from the discharge valve to the discharge nozzle is
It must be constantly filled with the polymer produced from the previous batch. A method for filling the polymer discharge circuit with produced polymer will be specifically explained based on FIG. FIG. 1 is a schematic cross-sectional view showing the polymerization can and the vicinity of the discharge part of the present invention. In the figure, 1 is a polymerization can, 2 is a jacket for heating the polymerization can, 3 is a discharge valve, 4 is a discharge mouthpiece, 5 is a base blind plate, and 6 is a jacket for heating the discharge circuit. First, when polymer discharge is completed, the discharge port 4 is sealed with a blind plate 5, and then the remaining polymer is allowed to flow down the wall surface of the polymerization can 1, and the polymer flows into the polymer discharge circuit from the discharge valve 3 to the discharge port 4. One method is to close the discharge valve 3 after it is filled. Alternatively, when the polymer discharge is completed, the discharge valve 3 is closed and the discharge port metal 4 is sealed with the blind plate 5, and then the discharge valve 3 is further opened, and the remaining polymer is allowed to flow down the wall surface of the polymerization can 1 and discharged. It is also possible to use a method in which the discharge valve 3 is closed after the polymer discharge circuit from the valve 3 to the discharge nozzle 4 is filled with polymer. Here, it is necessary to keep the temperature of the jacket portion 6 which fills the polymer discharge circuit with the produced polymer and heats the polymer discharge circuit to 250° C. or lower, preferably 240° C. or lower. That is, the deterioration of the polymer is easily affected by the temperature of the jacket portion 6, and even if the polymer discharge circuit is filled with the generated polymer, if the temperature of the jacket portion 6 heated is 250° C. or higher, the polymer deterioration is significant. Examples of heating methods for the jacket portion of the polymer discharge circuit include heating with an aluminum block heater and heating with other heat medium vapor. Here, maintaining the temperature of the jacket below 250℃ means that the polymer in the discharge circuit is in a molten, semi-molten, or semi-molten state.
This also includes cases where the polymer solidifies.
After the polymer has solidified, there is no harm in melting the polymer again in time to start dispensing the next batch. According to the present invention, the generation of carbonized foreign matter due to contamination of the discharge section, which is a disadvantage of batch polymerization, can be significantly reduced, and the quality of the polymer can be significantly improved. The present invention will be explained in more detail with reference to Examples below. Note that polymer foreign matter in the present invention was measured by the following method. Chips 5 minutes after starting dispensing after 20 batch polymerization
Weighed 200g (approximately 5000 chips) and counted the chips containing black foreign matter with the naked eye. Examples 1-2, Comparative Examples 1-4 31.6 parts of terephthalic acid, 13.5 parts of isophthalic acid,
1,4-butanediol 44 parts, number average molecular weight 1000
44.3 parts of polytetramethylene glycol, 0.04 parts of tetrabutyl titanate, and 0.02 parts of monobutyltin oxide were charged into an elastization reaction tank equipped with a rectification column and a stirrer, and the esterification reaction was carried out while gradually raising the temperature from 160°C to 230°C. The resulting water and tetrahydrofuran were distilled off through a rectification column.
After the esterification reaction was completed, 0.10 parts of tetrabutyl titanate was dissolved in a small amount of 1.4-butanediol as a polycondensation catalyst, and "IRGANOX" 1010 (manufactured by Nippon Ciba-Geigy) was added as a stabilizer.
0.10 part was suspended in a small amount of 1,4-butanediol and added. Next, the esterification reaction product was transferred to a polycondensation reaction tank, and the pressure was gradually reduced from normal pressure to 1 mmHg or less over 1 hour, and the temperature was raised to 245°C at the same time.
After polycondensation was carried out to a predetermined degree of polymerization and stirring power load at 1 mmHg or lower, the vacuum was broken with N ₂ and the mixture was further pressurized to 2 Kg/cm ² G. Here, the temperature of the jacket part of the polymer discharge circuit leading from the discharge valve to the low outlet metal was controlled at 240±5°C, and the polymer was discharged through this discharge circuit to form chips. After the discharge was completed, the discharge circuit was kept filled with polymer in the following manner until the start of the next batch of discharge. The discharge circuit was filled with polymer in the following manner. In FIG. 1, after the polymer discharge is completed, the discharge valve 3 is closed, and a blind plate 5 is attached to the discharge mouth metal 4.
Next, the discharge valve 3 is opened, and after the polymer discharge circuit from the discharge valve 3 to the discharge port metal 4 is filled with polymer (filling time is approximately 5 minutes), the discharge valve 3 is closed. Next, a new low polymer was transferred into the polymerization tank, and the polymerization described above was repeated. Table 1 shows the contamination state of the discharge circuit and the amount of foreign matter in the chips after polymerizing 20 batches in this manner. Furthermore, for comparison, Table 1 summarizes the contamination status of the discharge circuit after 20 batches of polymerization when the jacket temperature conditions were changed and when the discharge circuit was not filled with polymer.

【table】

【table】 [Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing an example of the polymerization can and the vicinity of the discharge section used in the present invention. 1: Polymerization can, 2: Jacket for heating the polymerization can,
3: Discharge valve, 4: Discharge mouthpiece, 5: Mouth blind plate,
6: Jacket for heating the discharge circuit.

Claims (1)

[Claims] 1 When producing a polyester-polyether copolymer containing aromatic dicarboxylic acid or its ester-forming derivative, 1,4-butanediol, and polyalkylene glycol as main components by a batch polymerization method, discharging the previous batch is completed. After that, until the start of dispensing the next batch, the polymer dispensing circuit from the dispensing valve to the dispensing nozzle is filled with the polymer produced in the previous batch, and the temperature of the jacket part that heats the polymer dispensing circuit is set to 250°C. 1. A method for producing a polyester-polyether copolymer, the method comprising maintaining the temperature at or below .degree.