JPH0520452B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to a method for producing a copolyester that can be synthesized only by melt polymerization and has good heat resistance using low-cost raw materials. <Prior art> A copolymerized polyester consisting of a polyester unit produced from an aromatic hydroxycarboxylic acid, a polyester unit produced from an aromatic diol and an aromatic dicarboxylic acid, and a polyester unit produced from an alkylene glycol and an aromatic dicarboxylic acid has been disclosed in Japanese Patent Publication No. Publication No. 51-8395, Japanese Unexamined Patent Publication No. 58-84821
It is disclosed in the publication number etc. JP-A-51-8395 and JP-A-58-84821
The copolymerized polyester disclosed in the publication is a
Acetylated aromatic hydroxycarboxylic acid, b
A polyester formed by condensing an aromatic dicarboxylic acid and an alkylene glycol, c, an acetylated product of an aromatic diol, and d, a first step of charging and condensing an aromatic dicarboxylic acid, and a second step of reducing the pressure of the reaction system to obtain a high molecular weight. It is described that it is manufactured by a method consisting of steps. Furthermore, JP-A-62-41220 discloses (i) an aromatic hydroxycarboxylic acid, (ii) a polyester formed by condensing an aromatic dicarboxylic acid and an alkylene glycol, (iii) a very small amount of an aromatic diol, and ( iv) A method for producing a copolymerized polyester is disclosed, which involves reacting (ii) with (i) using acetic anhydride and then acetylating it with (iv). <Problems to be Solved by the Invention> However, in the production methods described in JP-A-51-8395 and JP-A-58-84,821, the aromatic hydroxycarboxylic acid and the aromatic diol are pre-processed into an acetylated product in separate steps. The polymer cannot be obtained at low cost. Furthermore, in the production method described in JP-A-62-41220, since aromatic dicarboxylic acid is not copolymerized, only a polymer with low heat resistance and insufficient molecular weight is obtained. Furthermore, since (iv) acetic anhydride is added later, it is necessary to cool the reaction system midway through, which makes the reaction time long and the reaction complicated. An object of the present invention is to stably produce a copolyester in large quantities that uses non-acetylated monomers and has good heat resistance and high mechanical properties. <Means for solving the problems> That is, the present invention provides an aromatic hydroxycarboxylic acid having the following structural unit (), a polyester obtained by condensing an aromatic dicarboxylic acid having the following structural unit () and an alkylene glycol, and the following: aromatic diol having a structural unit (),
When producing a copolyester by reacting an aromatic dicarboxylic acid having the following structural unit () with acetic anhydride, the following structural unit ()
This is a method for producing a copolymerized polyester, which is characterized in that part or all of a polyester obtained by condensing an aromatic dicarboxylic acid having the following and an alkylene glycol is added after the reaction system is heated to a temperature of 150°C or higher. HO−Ar ₁ −COOH () (−O−R ₁ −O ₂ C−Ar ₄ −CO−) _o () HO−Ar ₂ −OH () HOOC−Ar ₃ −COOH () (However, Ar ₁ ~ Ar ₄ is a divalent aromatic group, R ₁ is a divalent alkylene group, and Ar ₁ to _{Ar 4} may be the same or different from each other.) The copolyester produced in the present invention is the above-mentioned copolyester. It has structural units of (), (), and (). Ar ₁ to _{Ar 4} are divalent aromatic groups, and may be the same or different from each other, or may be mixed. Preferably used Ar ₁ is

[Formula] etc., and as Ar ₂ ,

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

Among them, 4,4'-biphenylene group, p-phenylene group, and a mixture of both are particularly preferred. In addition, Ar ₃ and Ar ₄ that are preferably used include:

【formula】

【formula】

【formula】

【formula】

【formula】

[Formula] (wherein X represents a hydrogen atom or a chlorine atom), etc. In either case, paraphenylene groups or the coexistence of paraphenylene groups and other groups are particularly preferred. Further, R ₁ is a divalent alkylene group, and (--CH ₂ --) ₂ is particularly preferred. The copolymerized polyester produced in the present invention is a polyester raw material consisting of an aromatic hydroxycarboxylic acid, an aromatic diol, and an aromatic dicarboxylic acid having the following structural units (), or the above-mentioned,
, and a polyester raw material consisting of a part of a polyester formed by condensing an aromatic dicarboxylic acid and an alkylene glycol with acetic anhydride to produce part or all of a polyester formed by condensing an aromatic dicarboxylic acid and an alkylene glycol. It is manufactured by requiring post-addition to the reaction system at a temperature of 150°C or higher. Aromatic hydroxycarboxylic acids and aromatic diols form corresponding acetyl compounds through acylation with acetic anhydride, and polyesters formed by condensing aromatic dicarboxylic acids and alkylene glycols form corresponding polyester fragments through acid decomposition. , these and the dicarboxylic acid react sequentially by deacetic acid reaction, and finally become a high molecular weight polymer. In addition, since a copolymerized polyester with homogeneous optical anisotropy cannot be obtained by performing polymerization in a solid polydisperse state until part or all of it becomes solid, polymerization is performed until a uniform molten state is obtained. It is preferable. In the production method of the present invention, the raw materials for are usually 5 to 95 mol%, 5 to 95 mol%, and 5 to 95 mol% for the total 100 mol% of and.
The mole percentage range is preferably 0.7 to 1.3 times the mole amount. From the viewpoint of heat resistance of the polyester to be produced, in particular, [+] is in the range of 77 to 95 mol%, and is in the range of 5 to 23 mol%, and the molar ratio of / is 75/25 to 75/25 to 100 mol% of the total of and. 95/5 range,
It is preferably used in an amount of 0.9 to 1.1 times the amount by mole. However, the molecular weight is the average of repeating units. In particular, in the case of polyethylene terephthalate, the molecular weight is assumed to be 192.17 and the amount to be charged is converted. Further, acetic anhydride is used in a molar amount of 1.0 to 1.5 times, preferably 1.05 to 1.2 times, based on all the hydroxy groups of the starting materials. In the production method of the present invention, it is preferable to post-add 5% by weight or more, preferably 50% by weight or more, and most preferably 100% by weight, that is, the entire amount is post-added. The feature of the present invention is that by adding some or all of the above to the reaction system later, production stability during mass synthesis of copolyester is improved compared to when all of the above are added at once. The aim is to show an extremely high improvement effect on the The reason for this is that by introducing the particles into a reaction system with a temperature of 150°C or higher, this is especially true when the particles are large in size, such as when the particles are chips.
This solves the inconvenience in the production process of agglutination and fusion during reaction, which makes it impossible to stir. The present invention also provides a practical and stable production process, particularly for large scale polymer synthesis. The temperature for adding is 150℃,
Preferably it is 200-250°C. The temperature of the reaction system is
At temperatures below 150°C, the decomposition reaction is not rapid, and polymer aggregation and fusion may occur. The decomposition reaction of 200 to 250 occurs more quickly at higher temperatures.
Addition at °C is preferred. In the manufacturing method of the present invention, there is no particular restriction other than that the above-mentioned operations are essential, and other raw materials may be added all at once. Another example is a method of post-adding the aromatic dicarboxylic acid of and to the reaction system of (++). In this case, there is an advantage that a copolyester can be obtained in which the decrease in molecular weight of the polymer during heating is particularly reduced. There is no particular restriction on the order of addition of and.
Even if we add to the reaction system of (++) and then add more, we add to the reaction system of (++),
It doesn't matter if you add more or you can add and at the same time. Although the reaction in the production method of the present invention is not certain, it is considered as follows. First, it undergoes acylation with acetic anhydride at temperatures below 150°C, which decomposes and fragments at higher temperatures. Polycondensation including further increases the molecular weight. In addition, as a preferred method of production, aromatic hydroxycarboxylic acid, aromatic diol, and acetic anhydride are charged into a reaction vessel, and heated at 80°C under a nitrogen stream.
The acetylation reaction is carried out at ~300°C, preferably between 100°C and 250°C. Once the acetylation reaction has progressed and a certain amount of acetic acid has been distilled out, the reaction system is heated to 150°C or above.
Preferably, a polyester obtained by condensing an aromatic dicarboxylic acid and an alkylene glycol at a temperature of 200 to 250°C is introduced into the reaction system. After further advancing the reaction, the temperature is further increased to 260 to 330℃, preferably 290 to 320℃.
Examples include a method of obtaining a polymer by polymerizing under vacuum at °C. Although the reaction in the production method of the present invention proceeds without a catalyst, metal compounds such as stannous acetate, zinc acetate, acetimone acetate, antimony trioxide, tetrabutyl titanate, sodium acetate, potassium acetate, metallic magnesium, etc. In some cases, it may be preferable to add it. Further, the melt viscosity of the copolymerized polyester of the present invention is preferably 10 to 15,000 poise, particularly preferably 20 to 5,000 poise. Note that this melt viscosity has a shear rate of 1000 when it has optical anisotropy (liquid crystal start temperature + 40°C).
(1/sec) using a Koka type flow tester. On the other hand, the logarithmic viscosity of this copolymerized polyester can be measured in pentafluorophenol at (0.1 g/dl concentration, 60°C),
0.5 to 5 dl/g is preferred, and 1.0 to 3.0 dl/g is particularly preferred. In addition, when polycondensing the copolymerized polyester produced in the present invention, adipic acid,
Aliphatic dicarboxylic acids such as azelaic acid, sebacic acid, dodecanedioic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4- Aliphatic or alicyclic diols such as cyclohexanedimethanol may be further copolymerized within a small proportion that does not impair the object of the present invention. The production method of the present invention is one in which a polymer with a high degree of polymerization can be obtained using only the melt polymerization method, and the polymer produced thereby exhibits good optical anisotropy, mechanical properties, and heat resistance, and is suitable for extrusion molding, It can be used in ordinary melt molding such as injection molding and blow molding, and can be processed into fibers, films, three-dimensional molded products, containers, hoses, etc. In addition, the strength of the molded article obtained in this way can be increased by heat treatment, and the elastic modulus may also be increased. This heat treatment can be carried out by heat treating the molded article in an inert atmosphere (eg nitrogen, argon, helium or water vapor) or in an oxygen-containing atmosphere (eg air) at a temperature below the melting point of the polymer. This heat treatment may or may not be carried out under tension, and can be carried out for several tens of minutes to several days. For the copolymerized polyester produced by the present invention,
Reinforcing materials such as glass fiber, carbon fiber, asbestos, fillers, nucleating agents, pigments, antioxidants, stabilizers,
Additives such as plasticizers, lubricants, mold release agents, and flame retardants, as well as other thermoplastics, can be added to impart desired properties. <Example> The present invention will be further described below with reference to Examples. Example 1 1036 g (7.5 mol) of p-hydroxybenzoic acid in a 5 reactor equipped with a stirrer and a motor.
4,4'-dihydroxybiphenyl 186g (1 mol), terephthalic acid 166g (1 mol), acetic anhydride
1067g (10.44mol) was charged and reacted at 145°C for 1.5 hours. During this period, about 50 c.c. of acetic acid distillation was observed. After this, the temperature was increased at a rate of 50℃ per hour to 240℃.
Keeping the temperature constant at °C, the intrinsic viscosity decreases in 30 minutes.
288 g (0.075 mol) of polyethylene terephthalate having an average size of 1 mm x 4 mm x 4 mm was charged. As the mixture was added, the reaction was stirred vigorously. Further raise the temperature to 300℃ for 1 hour,
The pressure was reduced to 0.5 mmHg over the next 1 hour, and polymerization was continued for an additional 2 hours to complete the reaction. In pentafluorophenol of the obtained polymer
The logarithmic viscosity at a concentration of 0.1 g/dl at 60°C was 1.80 dl/g. This polymer was placed on the sample stage of a polarizing microscope, and the optical anisotropy was confirmed under elevated temperature and shear. As a result, the liquid crystal onset temperature was 266°C, indicating good optical anisotropy. The theoretical structural formula of this polymer is shown by the following formula. Example 2 Into the same apparatus as in Example 1, 1036 g (7.5 mol) of p-hydroxybenzoic acid, 180 g (1 mol) of 4,4'-dihydroxybiphenyl, and 1067 g (10.44 mol) of acetic anhydride were added.
mol) and reacted at 145°C for 1.5 hours. During this period, approximately 50 c.c. of acetic acid distillate was observed. After this,
Add 166 g (1 mol) of terephthalic acid, raise the temperature at a rate of 50°C per hour, keep the temperature constant at 235°C, and add 288 g (0.075 mol) of the same polyethylene terephthalate as in Example 1 over 30 minutes. did. As the mixture was added, the reaction was stirred vigorously. moreover
Raise the temperature to 300℃ over 1 hour, and in the next hour
The pressure was reduced to 0.5 mmHg, and polymerization was further carried out for 2 hours to complete the reaction. The logarithmic viscosity of this polymer is 1.84 dl/
It was hot at g. Comparative Example 1 The same amounts of p-hydroxybenzoic acid, 4,4'-dihydroxybiphenyl, terephthalic acid, acetic anhydride, and polyethylene terephthalate as in Example 1 were charged into the same apparatus as in Example 1. After stirring at 145° C. for 1 hour, the stirring load became so large that stirring became impossible. For this reason, heating is stopped and after cooling,
Upon disassembly of the apparatus, polyethylene terephthalate pellets were found fused to the bottom of the reactor and wrapped around the stirring spring. From the above results, it is difficult to stably obtain a copolymer polyester in large quantities using the method of Comparative Example 1, in which the polymer raw materials were added all at once. It is clear that it can be obtained stably. <Effects of the invention> By the method of the invention, using low-cost raw materials,
It has become possible to stably produce large quantities of copolymerized polyester with good heat resistance.

Claims (1)

[Scope of Claims] 1. An aromatic hydroxycarboxylic acid having the following structural unit (), a polyester obtained by condensing an aromatic dicarboxylic acid having the following structural unit () with an alkylene glycol, and an aromatic compound having the following structural unit () When producing a copolyester by reacting a diol, an aromatic dicarboxylic acid having the following structural unit (), and acetic anhydride, a polyester obtained by condensing an aromatic dicarboxylic acid having the following structural unit () and an alkylene glycol. A method for producing a copolyester characterized by adding part or all of it to a reaction system at a temperature of 150°C or higher. HO−Ar ₁ −COOH () (−O−R ₁ −O ₂ C−Ar ₄ −CO−) _o () HO−Ar ₂ −OH () HOOC−Ar ₃ −COOH () (However, Ar ₁ ~ Ar ₄ is a divalent aromatic group, R ₁ is a divalent alkylene group, and Ar ₁ to Ar ₄ may be the same or different.)