JPS6221808B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for bulk polycondensation of aromatic polyesters to obtain solid polydisperse polymers. More specifically, it is the most rational bulk polycondensation method for aromatic polyesters, in which monomers to solid polydispersions are polymerized in the same polymerization tank to produce the desired polymer.

Conventional aromatic polyester polymerization methods include interfacial polymerization, suspension polymerization, solution polymerization, and bulk polymerization. , bulk polymerization is the most streamlined manufacturing method. The method for producing oxybenzoyl polyester is patented in the U.S. Patent No.
No. 2728747, No. 2600376, Journal. of. Applied Polymer Science Vol. 2 No. 5 (1959
year) pp. 198-202, Special Publication 1979-6796, Special Publication 1977-
A method for producing a copolyester containing 37357 and hydroxybenzoic acid is described in Japanese Patent Publication No. 47-4780. Bulk polymerization methods for oxybenzoyl polyesters and copolyesters are known. The manufacturing method is specifically described in Journal of Applied Polymer Science, Vol. 2, No. 5 (1959), Japanese Patent Publication No. 48-37357, at 300°C under reduced pressure.
As the polymerization progresses, the melt viscosity of the polymer increases, and as the polymerization continues, the melt viscosity becomes so high that stirring is no longer effective. If the polymer is solidified in this state, the degree of polymerization will not increase, so the polymer is cooled and pulverized to a particle size of 0.8 mm, or the powder is soaked in acetone and heated to increase the degree of polymerization to promote crystallization. . However, the present inventors found that when the polymer produced by the polymerization of monomers is constantly applied a shearing force that prevents the polymer from solidifying at the polymerization temperature and the polymerization proceeds, the polymerization continues without stopping stirring. We found that we can proceed with this. Furthermore, in order to prevent the polymer from solidifying, it is important to apply a high shearing force without lowering the polymerization temperature, and to conduct the polymerization while applying a shearing force at a temperature below the desired fusion temperature of the polymer. Discovered a polymerization method that allows the polymer to be polymerized in a solidified polydisperse state until substantially all of the polymer becomes a solid phase without solidifying the polymer, thereby allowing the desired polymer to be easily removed from the polymerization tank as a solid polydisperse. Ta. In the case of the bulk polymerization method, once the polymer is solidified, an abnormally high shearing force is required to turn it into a solid polydisperse, and at the same time local heating occurs on the walls of the polymerization tank, causing the polymer to deteriorate. This is the most important thing to do as it may result in decomposition or abnormal molecular weight distribution.
In any type of bulk polymerization method, this is the most important point. There are many cases of failure due to solidification. To solve this problem, the molten polymer is taken out of the tank before it solidifies, cooled, crushed, and heated in the solid phase to increase the degree of polymerization, which reduces the quality of the polymer due to abnormal heating. The methods used before the present invention prevented this. However, this method is extremely complicated. In order to avoid this complication, the present invention aims to maintain or increase the temperature of polymers by applying sufficient shearing force to prevent solidification at the polymerization temperature in the same polymerization tank, and at the same time, to maintain or increase the temperature to proceed with polymerization. This is the most streamlined bulk polymerization method with stable quality, in which a solid polydispersion of the desired polymer can be finally taken out of the tank by operating the polymer at a temperature below the deposition temperature. That is, in the polycondensation reaction to obtain an aromatic polyester containing hydroxybenzoic acid, the present invention involves applying sufficient shearing force to keep the polymer in a polydisperse state while polymerizing until substantially all of the polymer becomes a solid polydisperse. This is a bulk polycondensation method characterized by the fact that it is carried out. The fusion temperature referred to herein is the upper limit temperature at which the solid polydispersions do not fuse to each other when the polymer obtained by polymerization is made into a solid polydispersion. Moreover, the solid polydispersion means one in a dispersed state such as a powder or flake.

More preferably, the powder has a uniform particle size. In carrying out the present invention, specifically, monomers that are fluid, especially liquid, at the polymerization temperature, or in some cases, some monomers may not be liquid but may be in a slurry state. However, it may also contain other solvents. A high shear force is applied, preferably without substantially reducing the temperature of the system, during which time the system becomes a substantially all-solid polydisperse, rather than being in a substantially liquid state. varies depending on the type and crystallinity of the polymer.

It is important that the shear force be that necessary to achieve a solid polydispersion. In order to obtain a solid polydisperse, it is important that the polymerization temperature is below the fusion temperature. Even if the polymerization temperature is increased to increase the polymerization rate, the fusion temperature will increase as the polymerization progresses, but the polymerization temperature must be increased at a rate less than or equal to the rate at which the shearing force is sufficient to maintain the solid polydispersion. If this is added, the object of the present invention can be achieved.

The polymerization system applicable to the present invention is any system as long as the temperature during which a substantially liquid monomer changes into a solid polydispersion is below the fusion temperature of the polymer by applying a shearing force at the polymerization temperature. It can also be applied to

Particularly preferred is a polymerization system that is crystalline and becomes a solid polydisperse due to shearing force, and then becomes a powder without mutual adhesion. In addition, in the case of a polymer whose melt viscosity is highly dependent on temperature, the present invention can be more easily accomplished if the polymer is made into a solid polydispersion because the dispersion is difficult to re-fuse.

The present invention is a bulk polycondensation method for aromatic polyesters as shown below. i.e. [In the above formula, X is a hydrocarbon group (1 to 20 carbon atoms),
-O-, -SO ₂ -, -S-, -CO-, etc., m
is 0 or 1, and n is 0 or 1. p=0
When q=r=3 to 600, when q=r=0, p=
3-600 preferably 20-200, or p+q+r
= 3 to 600, preferably 20 to 200, where q = r], and the reaction formula is [In the above formula, m, n, and X have the same meanings as above, and R ¹ , R ⁵ and R ⁶ are a benzoyl group, a lower alkanoyl group, or preferably hydrogen,
R ² , R ³ and R ⁴ are hydrogen, a benzyl group, a lower alkyl group, or preferably a phenyl group.] Any polymerization reaction that allows bulk polymerization may be used. Examples of the compound of formula () include para-hydroxybenzoic acid, meta-hydroxybenzoic acid, phenyl-para-hydroxybenzoate,
phenyl meta-hydroxybenzoate, paraacetoxybenzoic acid, metaacetoxybenzoic acid,
and isobutyl-para-acetoxybenzoate, 3,5-dimethyl-4-hydroxybenzoic acid, phenyl 3,5-dimethyl-4-acetoxybenzoate, and 3,5-dimethyl-4-hydroxybenzoate. Examples of the compound of formula () include isophthalic acid, teresteric acid, 2-methylterephthalic acid, diphenyl terephthalate, diethyl isophthalate, methyl ethyl terephthalate, isobutyl half ester of terephthalic acid, terephthalic acid chloride, and isophthalic acid chloride. Examples of compounds of formula () include hydroquinone, resorcinol, diacetoxyresorcinol, 4,4'-biphenol, 4,4'-
Oxyphenol, 4,4′-thiobiphenol,
4,4'-dihydroxydiphenyl sulfone, chloro-substituted hydroquinone, 2,2'-bis(4-hydroxyphenyl)propane, 1,1'-bis(4-
Hydroxyphenyl) cyclohexane, 1・1′-
Bis(4-hydroxyphenyl)ethane, bis(4-hydroxyphenyl)methane, 2,2'-bis(4-hydroxy-3,5-dibromophenyl)propane, 2,2'-bis(4- hydroxy-
3,5-dimethylphenyl)propane, 2,2'-
Bis(4-hydroxy-3,5-dichlorophenyl)propane, bis(4-hydroxyphenyl)
There are ketones, etc.

The condensation reaction of the polyester of the present invention is about 200 to 400
It can be carried out preferably at about 250-350°C.
Since the rate of condensation generally increases with increasing temperature, it is advantageous to carry out the condensation at relatively high temperatures. The maximum temperature that can be used depends in part on the boiling point or decomposition point of the monomer or oligomer used;
This temperature limit initially carries out condensation at a relatively low temperature,
The temperature is increased as the condensation progresses. first
At a temperature of 180-250℃, then raised to 250-380℃
Polymerization is carried out at a temperature of preferably from 300 to 360° C. under normal pressure or reduced pressure. Once it becomes a solid polydispersion, it is possible to raise the temperature while considering the fusion temperature and decomposition temperature, preferably 310 to 400℃, preferably 310 to 370℃,
However, as long as the temperature is below the decomposition temperature and below the fusion temperature, the higher the temperature, the faster the reaction rate will be.

The present invention is a bulk polycondensation method and does not require post-treatment of the resulting polymer. Therefore, from the purpose of the present invention, it is preferable not to use a catalyst, but in order to increase the reaction rate, a gaseous catalyst such as a Lewis acid is preferable. Hydrogen halides are preferred, especially
HCl is preferred. Commonly available catalysts such as polyesters can be used when catalyst residues do not adversely affect the polymer.

It is also possible to further add stabilizers, colorants, fillers, etc. to the present invention. Especially for fillers,
If the filler is inert to polymerization, it can be easily turned into a solid polydispersion by adding it. The object of the present invention can be more easily achieved by adding a filler to a polymerization system that is difficult to form into a solid polydispersion. Fillers include, for example, silica, powdered quartz or sand, fumed silica, silicon carbide, aluminum oxide, glass fibers, tin iron oxide, zinc oxide, carbon, graphite; as pigments titanium dioxide and other inorganic pigments and heat-resistant organic pigments are used.

In the present invention, the monomer is stirred in a low viscosity state that is substantially liquid at the polymerization temperature, and as the polymerization progresses, the monomer becomes highly viscous, and by applying shear force, substantially all of the monomer becomes a solid polydisperse. This is the most streamlined bulk polycondensation method, in which the purpose is achieved by carrying out three stages of stirring of the solid polydispersion in the same polymerization tank, and the final extraction is the solid polydispersion. In order to satisfy such a three-stage state change, the stirring power is not particularly limited, but preferably 0.75 KW to 100 KW/m ² is applied. The optimum stirring power varies depending on the type of polymer, but in the case of a polymer with a high degree of crystallinity, the purpose can be achieved with a relatively small stirring power. It is important to apply such shearing force to prevent solidification during the transition from a molten state to a solid polydispersion, and when the transition from a molten state to a solid polydispersion occurs, the particle size of the solid It is important to always apply a shearing force such that the bulk of the solid polydispersion is 0.5 mm or less. If the particle size is 0.5 mm or more or solidified, the speed of the condensation reaction will decrease in subsequent polymerization, the molecular weight of the polymer will become significantly non-uniform, the physical properties of the polymer will deteriorate, or the thermal conductivity will decrease. or cause local heating.

In carrying out the present invention, the polymerization vessel is a stirring equipment commonly used for high viscosity reactions, such as an anchor type stirrer, a multistage type stirrer, a spiral band stirrer, a spiral shaft stirrer, etc., or a modified version thereof. Stirring tank type polymerizer equipped with stirring equipment, Warner type mixer with strong mixing power, Banbury mixer,
It is preferable to use a pony mixer, a Mueller mixer, a roll mill, a continuously operable co-kneader, a hug mill, a gear compounder, etc., but there are no particular limitations thereon.

The present invention will be explained below with reference to Examples, but the Examples are intended to show preferred embodiments of the present invention, and are not intended to limit the scope of the present invention.

Example 1 138 g of parahydroxybenzoic acid, 170 g of phenyl acetate,
318 g of diphenyl terephthalate and 500 g of orthodichlorobenzene (boiling point 179.2°C) were added, and nitrogen was introduced. The polymerization contents were heated to 180°C to which HCl was introduced into the reaction mixture. Stir at 180°C for 6 hours, remove acetic acid, stop introducing HCl, add 111 g of hydroquinone, 100 g of orthodichlorobenzene.
g was added and the temperature was further raised to remove orthodichlorobenzene. At this point, the torque increased, but when the temperature was further increased from 220℃ to 320℃ for 10 hours, the torque gradually decreased and the stirring was stopped.
When the temperature was continued at 320℃ for 16 hours, the torque gradually increased, and then when the temperature was further increased to 340℃ and the stirring power was increased and stirring was continued for 2 hours, the torque of the stirring blade further increased. A decline occurred. When the inside of the tank was observed at that point, the molten material had changed to powder. Then, polymerization was continued for an additional hour to form a complete powder. The powder was then cooled to 250°C and taken out of the tank. The total amount of distillate consisting of phenol, acetic acid, phenyl acetate, and orthodichlorobenzene was 971 g.
The recovered powder was 334 g (93% of theory). Differential thermal analysis revealed that a weak endotherm occurred at 405℃.
A strong endotherm occurred at 492°C. Further, when the melt changed to powder, the powder was taken out (38 g was taken out) and pulverized, and the fusion temperature was measured and found to be 381°C. The flow start temperature of this powder was determined as the outflow temperature under a pressure of 100 kg/cm ² using a die of 1 mm diameter x 10 mm length using a flow tester CFT-500 manufactured by Shimadzu Corporation, and was found to be 385°C. Injection molded at 390℃,
As a result of measuring tensile properties, the strength at room temperature is 923
Kg/cm ² , and the strength at 260°C was 253 Kg/cm ² .

Example 2 138 g of p-hydroxybenzoic acid, 332 g of isophthalic acid, p-
Add 372 g of p'-biphenol and 561 g of acetic anhydride, introduce nitrogen, mix, and reflux at 150°C for 2 hours.
Then, raise the temperature to 250℃ while distilling off acetic acid.
When the temperature is raised to 100%, most of the acetic acid produced by the acetylation reaction is distilled off. Hold at 250℃ for 2 hours and 250℃
Raise the temperature from 300℃ to 300℃. During this period, the torque increased, and when the temperature reached 300°C, the stirring power was increased and maintained for 1 hour, the torque suddenly increased, and when it was continued further, the torque decreased. Thereafter, it was held at 300°C for 2 hours. The inside of the tank was powdered. It was cooled to 250°C and the powder was taken out. The result of taking out the instantaneous powder when the torque decreased, pulverizing it, and measuring the fusion temperature.
It was 373℃. The flow onset temperature was 376°C.

The bending strength of the compression molded product was 701 Kg/cm ² .

Example 3 1380 g of parahydroxybenzoic acid and 1120 g of acetic anhydride were placed in a glass flask under nitrogen flow and heated to 150°C.
The mixture was refluxed for 2 hours, and acetic acid was distilled off while the temperature was raised. When the content reached 230°C, the acetylated paraacetoxybenzoic acid was transferred to a twin-screw type kneader that had been preheated to 230°C. It was liquid at this point.

Stirring was performed at low speed and the temperature was raised to 330℃ over 1 hour. When the temperature reached 310℃, an increase in torque was observed, so when the stirring speed was increased and polymerization proceeded, the inside of the tank turned into powder. It became. The result of taking out 100g of the powder and measuring the particle size.
73% were 0.1 mm or less. When polymerization was further continued at 330°C, the temperature in the tank showed the temperature trend shown by the powder. The reaction rate when it turned into powder was 95%.

The reaction was further continued for 2 hours to obtain 1130 g of fine powder. The yield was 94%. The particle size of the obtained powder was 91% less than 0.1 mm. Differential thermal analysis of the powder revealed an endotherm at 342°C. The weight loss on heating at 370°C for 1 hour in air was 0.65% by weight. The number average molecular weight was 11,000.

Claims (1)

[Claims] 1. Reaction formula [In the above formula, R ¹ , R ⁵ and R ⁶ are benzoyl groups,
It is a lower alkanoyl group, or preferably hydrogen, R ² , R ³ and R ⁴ are hydrogen, benzyl group, lower alkyl group or preferably phenyl group, and X is a hydrocarbon group (having 1 to 20 carbon atoms), - O-, _-SO2 -,-
S-, -CO-, etc., m is 0 or 1,
n is 0 or 1. When P=0, q=r=3~
An integer of 600: When q=r=0, p=an integer of 3 to 600: p+q+r=3 to 600, p, q, and r are integers, provided that q=r. ] In the polycondensation reaction to obtain an aromatic polyester, a shearing force sufficient to maintain the resulting polymer in a solid polydisperse state is constantly applied to the resulting polymer, and the polymerization is carried out without stopping stirring. According to
A bulk polycondensation method for aromatic polyester, characterized in that polymerization is carried out until substantially all of the produced polymer becomes a solid polydispersion without solidifying the produced polymer.