JPH01153719A - Production of copolymerized polyester - Google Patents

Abstract

PURPOSE:To obtain a polyester capable of giving an inexpensive molded article having high heat-resistance and resistant to the lowering of molecular eight with heat, by adding an aromatic dicarboxylic acid to a reaction system after the reaction. CONSTITUTION:A copolyester is produced from an aromatic hydroxycarboxylic acid of formula I, a condensed polyester of an aromatic dicarboxylic acid of formula II and an alkylene glycol, an aromatic diol of formula III, an aromatic dicarboxylic acid of formula IV (Ar1-Ar4 are bivalent aromatic group; R1 is bivalent alkylene) and acetic anhydride. In the above process, a part or total of the aromatic dicarboxylic acid is charged to the reaction system at 100-290 deg.C, preferably 150-280 deg.C after the acetylation reaction and the initial polymerization reaction and when a prescribed amount of acetic acid is distilled off from the system. The reaction is continued and the product is polymerized at 250-330 deg.C in vacuum to obtain the objective polymer.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is directed to a copolyester that can be synthesized only by melt polymerization and that can give molded products with good heat resistance using low-cost raw materials. This relates to a manufacturing method.

<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 is disclosed in Japanese Patent Publication No. It is disclosed in Japanese Patent Application Laid-Open No. 58-84821, etc.

JP-A-51-8395 and JP-A-58-848
The copolymerized polyester disclosed in Publication No. 21 includes a, an acetylated aromatic hydroxycarboxylic acid, b, a polyester obtained by condensing an aromatic dicarboxylic acid and an alkylene glycol, and an acetylated C1 aromatic diol;
d. It is described that it is produced by a method consisting of 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.

Additionally, Jikai No. 11g62-41220 discloses (i) an aromatic hydroxycarboxylic acid, (it) a polyester obtained by condensing an aromatic dicarboxylic acid and an alkylene glycol, (tit) a small amount of an aromatic diol, and (iv) After reacting (it) and (i) using acetic anhydride, (
Disclosed is a method for producing a copolymerized polyester which essentially includes addition of titanium titanium titanium chloride titanium titanium chloride titanium titanium chloride titanium titanium chloride titanium chloride titanium chloride titanium titanium titanium chloride titanium chloride titanium chloride titanium chloride titanium chloride titanium chloride titanium chloride titanium chloride titanium chloride titanium chloride titanium chloride titanium chloride titanium chloride titanium chloride titanium chloride titanium chloride titanium chloride titanium chloride titanium chloride titanium chloride titanium chloride titanium chloride titanium chloride chloride titanium chloride acetylated 100 chloride chloride acetylated by 100% chloride (iv).

<Problems to be solved by the invention> However, the manufacturing methods described in Japanese Patent Application Laid-open No. 5 i-8395" and Japanese Patent Application Laid-open No. 58-84821 have the following problems:
It is necessary to induce the aromatic hydroxycarboxylic acid and the aromatic diol into an acetylated product in separate steps in advance, and the polymer cannot be obtained at low cost. In addition, in the production method described in JP-A-62-41220, (1) the aromatic dicarboxylic acid is not copolymerized, resulting in Polymer 1 having low heat resistance and insufficient molecular weight. moreover,(
iv) Since acetic anhydride is added later, it is necessary to cool the reaction system midway through the reaction, resulting in a long reaction time and complicated reaction operation.

An object of the present invention is to use a non-acetylated monomer to obtain a copolyester having good heat resistance and high thermal stability at a low cost.

<Means for Solving the Problems> That is, the present invention condenses (1) an aromatic hydroxycarboxylic acid having the following structural unit (I>), (2) an aromatic dicarboxylic acid having the following structural unit (n), and an alkylene glycol. When producing a copolymerized polyester from ■ an aromatic diol having the following structural unit (DI), ■ an aromatic dicarboxylic acid having the following structural unit (IV), and ■ acetic anhydride, ■ the following structural unit (IV ) to the reaction system.
This is a method for producing a copolyester characterized by post-addition at ~290°C.

HOA, r t COOH (I ) + OROCAr
4 coh n(If>HOA r 20 H(DI
) HOOC-Ar -COOH(IV) (However, Ar
~Ar represents a divalent aromatic group, R□ represents a divalent alkylene group, and Ar~Ar4 may be the same or different from each other. ) The copolymerized polyester produced in the present invention is the above-mentioned (I), (II), (1) and (IV).
derived from. Ar to Ar 4' are divalent aromatic groups, which may be the same or different from each other, and may be a mixture thereof, particularly 4.4-monobiphenylene group, p-phenylene group, and both. Mixtures and the like are preferred.

Further, preferred examples include Ars and Ar (representing a hydrogen atom or a chlorine atom), which are particularly preferably paraphenylene groups or the coexistence of paraphenylene groups and other groups.

Moreover, R1 is a divalent alkylene group, especially +cH2
+2 is preferred.

The copolymerized polyester produced in the present invention is a polyester raw material consisting of (1) an aromatic hydroxycarboxylic acid, (2) a polyester formed by condensing an aromatic dicarboxylic acid and an alkylene glycol, and (2) an aromatic diol, or the above-mentioned (1) to (2) and (4) aromatic. A polyester raw material consisting of a part of group dicarboxylic acids is reacted with ■acetic anhydride, and part or all of an aromatic dicarboxylic acid having the following structural unit (IV) is post-added to the reaction system at 100 to 290°C. Manufactured as required.

■Aromatic hydroxycarboxylic acid and ■Aromatic diol■
After acylation with acetic anhydride, it becomes the corresponding aromatic acetoxycarboxylic acid and aromatic diacetoxy compound,
On the other hand, (2) a polyester formed by condensing an aromatic dicarboxylic acid and an alkylene glycol is induced into polyester fragments through acid decomposition. It is thought that these react with the aromatic dicarboxylic acid in a sequential manner through the deacetic acid reaction, and finally become a high molecular weight polymer.

In the production method of the present invention, the raw materials (■) to (■) are usually ■,
■ is in the range of 5 to 95 mol%, ■ is in the range of 5 to 95 mol%, ■ is in the range of 5 to 95 mol%, and ■ is in the range of 0.7 to 1.3 with respect to the total of 100 mol% of ■ and ■. It is preferably charged within the molar amount range.

From the point of view of the heat resistance of the polyester to be manufactured, in particular,
For the total of 100 mol% of and ■, [■10■] is 77
~95 mol%, ■ is in the range of 5 to 23 mol%, ■/■ molar ratio is in the range of 75/25 to 9515, ■ is 0 relative to ■
．． It is preferably used in a range of 9 to 1.1 moles.

However, ■ indicates the average of the repeating units as the molecular weight.

In particular, when ■ is polyethylene terephthalate, the molecular weight is 192.17.

In addition, acetic anhydride has 1
．． It is used in an amount of 0 to 1.5 times by mole, preferably 1.05 to 1.2 times by mole.

In the production method of the present invention, it is preferable that the aromatic dicarboxylic acid is usually post-added in an amount of 5% by weight or more, preferably 50% by weight or more, and most preferably 1% by weight, that is, the entire amount is post-added. .

The feature of the present invention is that among the above-mentioned ■ to ■, by adding part or all of ■ to the reaction system later, the heating time of the copolymerized polyester is The purpose is to show an extremely high improvement effect on thermal stability.

The reason for this is that when ■~■ are charged all at once, the aromatic hydroxyl groups of ■ and ■ react with acetic anhydride, and when the aromatic dicarboxylic acid of ■ becomes an acetyl form, the aromatic dicarboxylic acid of ■ undergoes an acid anhydride exchange reaction with acetic anhydride. Furthermore, this acetic anhydride repeatedly undergoes acid anhydride exchange reactions with carboxyl groups in the system to form acid anhydride bonds in the polymer chain, which is thought to result in poor stability during heating. Therefore, it is considered that the thermal stability was improved by first carrying out the acetylation reaction of the aromatic hydroxyl group with acetic anhydride and then adding the aromatic dicarboxylic acid (2) to suppress the acid anhydride exchange reaction.

Although there are no particular restrictions on the production method of the present invention other than the above-mentioned operations being essential, a preferred method for production is the condensation of (1) aromatic hydroxycarphonic acid, (2) aromatic dicarboxylic acid, and alkylene glycol. Polyester, aromatic diol, and anhydrous #acid are placed in a reaction vessel and heated at 80°C to 290°C, preferably 100°C under a nitrogen stream.
Acetylation reaction and initial polymerization are carried out at ~250°C.

At the stage where the acetylation reaction and initial polymerization have proceeded and a certain amount of acetic acid has been distilled out, the temperature is 100-290°C2, preferably 1
(2) Aromatic dicarboxylic acid is introduced into the reaction system at 50 to 280°C. After further reaction, 250 to 33
The polymer is obtained by polymerization under vacuum at 0°C5, preferably 290-320°C. Incidentally, it is also possible to add a part of the aromatic dicarboxylic acid (1), preferably 50% by weight or less, to the reaction system in advance in the same manner as in (1) to (2) and (2).

■The aromatic dicarboxylic acid is not particularly limited as long as it can be added in a predetermined amount into the system, but it may be sealed in a polymer capsule such as a polyethylene terephthalate bottle that will be melted, depolymerized, or copolymerized in the reaction system. The method of adding it is reliable and more preferable.

In addition, in the method of the present invention, the reaction proceeds even without a catalyst, but metal compounds such as stannous acetate, zinc acetate, antimony acetate, antimony trioxide, tetrabutyl titanate, sodium acetate, potassium acetate, and metallic magnesium are added. There are times when it is preferable to do so.

The melt viscosity of the copolymerized polyester produced in the present invention is preferably 10 to 15,000 poise, particularly 20 to 5,000 poise.
000 poise is more preferred.

Note that this melt viscosity is a value measured using a Koka type flow tester under the conditions of (liquid crystal starting temperature + 40° C.) and a shear rate of 1,000 (1/sec). - On the other hand, the logarithmic viscosity of this copolymerized polynisester can be measured in pentafluorophenol at a concentration of 0.1 g/dj and 60°C, preferably 0.5 to 5 dfJ/g, preferably 1.0 to 3.
Particularly preferred is 0 dj/g.

In addition, when polycondensing the copolymerized polyester produced in the present invention, in addition to the above-mentioned items 1 to 2, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, and dodecanedioic acid, and fats such as hexahydroterephthalic acid are used. Cyclic dicarboxylic acids, aliphatic and alicyclic diols such as 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanediol, and 1,4-cyclohexane dimetatool, etc. Further copolymerization may be carried out within a small proportion that does not impair the purpose of the invention.

The copolymerized polyester of the present invention obtained in this manner can be obtained as a polymer with a high degree of polymerization only by melt polymerization, exhibits good optical anisotropy, mechanical properties, and heat resistance, and can be used in extrusion molding, injection molding, compression molding, blow molding, etc. It can be subjected to ordinary melt molding, and can be processed into fibers, films, three-dimensional molded products, containers, hoses, etc.

For the copolymerized polyester of the present invention, reinforcing agents such as glass fibers, carbon fibers, and asbestos, fillers, nucleating agents, pigments,
Additives such as antioxidants, stabilizers, plasticizers, lubricants, mold release and flame release agents, and other thermoplastics can be added to impart desired properties.

In addition, the molded article obtained in this way can have its strength increased and may also have its elastic modulus increased by heat treatment. 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 under tension, and can be carried out for several tens of minutes to several days.

<Example> The present invention will be further explained below with reference to Examples.

Example 1 In a polymerization tester equipped with a stirring device, 51.79 g (0.375 mol) of p-hydroxybenzoic acid and 9.31 g (0.05 mol) of 4° 4-di-hydroxybiphenyl were added. about 0.6 polyethylene terephthalate 14.41
g (0,075 mol) acetic anhydride 53.34 g (0,5
22 mol) and reacted at 150°C for 1.5 hours. During this period, about 0.3 cc of acetic acid was observed to be distilled out. Then, 8.31 g (0.050 mol) of terephthalic acid was introduced into the system, and the temperature was raised at a rate of 50°C per hour until it reached 300°C. A small amount of aggregates thought to be caused by terephthalic acid were observed at around 250°C.
The pressure was reduced to 0.5 fflII + 14 g over 1 hour at °C, and polymerization was further carried out for 1 hour to complete the reaction.

0.1r of the obtained polymer in pentafluorophenol
/dj concentration and the logarithmic viscosity at 60°C was 1°86dj/g. When this polymer was heat treated in an oven at 150'C for 120 hours, the logarithmic viscosity was 1.82d, 0.
7 g, and the viscosity decrease was as small as 0.04 dJ/f. The theoretical structural formula of this polymer is shown by the following formula.

Examples 2 to 3 and Comparative Examples 1 to 2 The reaction was carried out in the same manner as in Example 1, using the same raw materials and reaction apparatus as in Example 1, except that the timing of addition of terephthalic acid was changed. These are summarized in Table 1.

In all of these, the logarithmic viscosity decreased by heat treatment. Comparative Example 1 is an example in which terephthalic acid was charged together with other raw materials, and a large amount of associated products of terephthalic acid was observed at around 250'C. Moreover, the logarithmic viscosity decrease was also large. In Comparative Example 2, terephthalic acid was added when the reaction system was heated to 300°C. In this case, unreacted terephthalic acid remained in the resulting polymer, so a non-uniform polymer could not be obtained.

Table 1 From the above results, it is clear that by adding terephthalic acid after the acetylation reaction has progressed, a copolymerized polyester with suppressed molecular weight reduction during heating can be obtained.

<Effects of the Invention> The method of the present invention has made it possible to produce a polymer with good heat resistance using inexpensive raw materials and a simplified method.

Claims (1)

[Claims] (1) Aromatic hydroxycarboxylic acid having the following structural unit (I), (2) Polyester formed by condensing an aromatic dicarboxylic acid and alkylene glycol having the following structural unit (II), (3) The following structural unit (III) ) and (4) an aromatic dicarboxylic acid having the following structural unit (IV) and (5) acetic anhydride. Part or all of the group dicarboxylic acid is added to the reaction system.
A method for producing a copolyester characterized by post-adding at 0 to 290°C. HO-Ar_1-COOH(I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) HO-Ar_2-OH(III) HOOC-Ar_3-COOH(IV) (However, Ar_1 to Ar_4 are divalent aromatic groups, R_1
is a divalent alkylene group, and Ar_1 to Ar_4 may be the same or different from each other. )