JPS5840317A - Production of aromatic polyester - Google Patents

Abstract

PURPOSE:To obtain an aromatic polyester having improved moldability and orientation during molding, by carrying out bulk polymerization by adding a specified polyester to the polymerization system in the production of a fully aromatic polyester. CONSTITUTION:In the production of a fully aromatic polyester represented by formulaI, wherein X is 1-4 C alkyl, -O-, -SO2- or -CO-, m and n are each 0 or 1, d:e=1:1-10:1, e:f=9:10-10:9, and the substituents of an aromatic ring are para or meta to each other; 5-50wt%, based on the final polymer, polyester represented by formula II, wherein p+q is 10-1,000, p/(p+q)>=0.8, is added to the polymerization system, and the polymerization is effected by a bulk polymerization process wherein no solvent is used. As components for the fully aromatic polyester, there can be used p-hydroxybenzoic acid, terephthalic acid, 4,4'-dihydroxydiphenyl and their derivatives.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing aromatic polyester. Fully aromatic polyester has excellent properties in terms of structure, but it stands out among all l#[I in terms of heat resistance. Among these, wholly aromatic polyesters produced from terephthalic acid, isophthalic acid, parahydroxybenzoic acid or its derivatives, and 4,4'-dihydroxydiphenyl or its derivatives are injection moldable and can be molded in various materials, including mechanically. Has excellent properties, electrical properties, thermal stability, etc., high heat resistance, chemical resistance, oil resistance, radiation resistance,
It has many excellent properties such as dimensional stability,
Chills used in various fields such as mechanical parts, electrical, electronic parts, and automobile parts have the disadvantage of high melt viscosity and poor moldability due to their high softening temperatures. Furthermore, since high molding temperatures are required, there are problems such as polymer deterioration and tube color during molding, and from these points of view as well, improvements in moldability have been desired.

Furthermore, such wholly aromatic polyesters have the property of being prone to curling during injection molding. There is a tendency for the shrinkage rate to be affected. Such anisotropy in molding shrinkage rate is unfavorable from the viewpoint of dimensional stability of the molded article.

Solve the problems of fully aromatic polyesters as described in αF, such as poor moldability (fluidity), easy orientation during injection molding, and anisotropy in shrinkage rate. Various methods have been used for this purpose. As a method for improving moldability, there is a method of blending with INN1 having better fluidity (good moldability). For example, it is blended with polyethylene terephthalate, polycarbonate, etc. and molded.

However, the aforementioned terephthalic acid, isophthalic acid, and parahydroxybenzoic acid%4. When mixing, granulating, and molding a fully aromatic polyester obtained from i%4'-dihydroxydiphenyl or the like with polyethylene terephthalate or polycarbonate, if each step is performed in a temperature range where the fully aromatic polyester is uniform, this Polyethylene terephthalate and polycarbonate, which have poor thermal stability at high temperatures, are prone to thermal decomposition (and these INII
The entire system in which I is stable and uniform does not become a uniform dispersion.

In order to homogenize the entire system, it is possible to lengthen the residence time of the particles in each process such as mixing, granulation, and molding, but this is far from achieving uniform dispersion, and the resulting state of dispersion is very large. This would require a considerable amount of time, which is not realistic.

Alternatively, in order to reduce the molding temperature of wholly aromatic polyester, a wholly aromatic polyester with a low molecular weight is used, and as shown in the previous example, it is mixed with a resin with excellent moldability. Although it is possible to perform granulation and molding, the various excellent properties of wholly aromatic polyesters will be degraded.

A blending method using a solution is also considered, but in the case of fully aromatic polyesters, a solvent that can uniformly dissolve the polyester without decomposition has not yet been found, and it can be said to be an extremely national problem.

If the dispersibility is insufficient, parts of the resin or molded product may deteriorate when exposed to solvents or reagents, variations may be observed from one tube to another during molding, and the strength of the molded product may be uneven. It may be.

As described below, it can be said that it is difficult to improve the moldability of the wholly aromatic polyester described in I from the blending method of this general structure.

A completely different method is to use copolymerization instead of blending. For polymers with rigid main chains such as fully aromatic polyesters, this method involves copolymerizing units with high flexibility, such as aliphatic segments such as ethylene glycol, in order to impart fluidity. . However, this method eliminates the heterogeneity seen in blends, improves fluidity, and improves moldability, but the many excellent properties that wholly aromatic polyesters inherently have, especially heat resistance, are significantly reduced ( preferable.

The second problem with wholly aromatic preesters, the anisotropy between orientation and molding shrinkage, can be suppressed to a certain extent by adjusting the injection molding conditions. Molding conditions such as injection direction and injection speed are controlled to control orientation. However, such a method has its drawbacks, and it goes without saying that improvements in the mM itself are necessary.

A commonly used method is to use a filler. The fillers are mainly inorganic materials such as glass fiber, graphite, quartz, titanium oxide-monooxide, and talc.

The usual purpose of using fillers is to improve mechanical strength;
Polyethylene terephthalate or polyamide (nylon)
For example, the -11 property can be significantly improved by filling with glass fiber or the like. It is also used for purposes that take advantage of the characteristics of other fillers, and may also be used as a strength-enhancing material. Glass for fully aromatic polyester
Orientation can be suppressed by filling several tens of percent of filler such as fibers. However, the strength (-11 property) is rather lower in the case of filling as the orientation is suppressed, which is different from that of ordinary thermoplastic resins such as polyethylene terephthalate and polyamide (nylon).

When a filler such as glass fiber is used for the purpose of suppressing deflection, there is a problem in addition to such a decrease in strength (rigidity) that it may damage the molding machine. Alternatively, depending on the use of the molded product, it may be preferable to have no filler (i.e., only resin), and so far no method has been found for fully aromatic polyester to suppress the orientation of the rut itself. .

In view of the current situation, the inventors of the present invention have conducted intensive studies to improve the moldability (flowability) of wholly aromatic polyesters and to suppress the orientation during molding, and as a result, they have succeeded in producing wholly aromatic polyesters. Sometimes, a certain type of polyester is present in a specific proportion in the polymerization reaction system, and the polymerization is carried out by a bulk polymerization method in which substantially no solvent is present, without reducing the excellent performance of wholly aromatic polyesters. The inventors have discovered that the above objects can be achieved and have arrived at the present invention.

That is, the present invention relates to the general formula A: (wherein x is an alkyl group of 01 to C4, -〇-0-802
- and -8- are -CO-, and m and n are 0 or l. The ratio of d:e ranges from 1:l to 1O:l
In this case, the ratio of e:f is between 9:1O and 10:9. Furthermore, the substituents on the aromatic ring in the above formula are in para or meta positions with respect to each other. ) When forming the wholly aromatic preester formed by the above, the polymerization reaction system is generally 2B: This invention relates to a method for producing an aromatic polyester, characterized in that the aromatic polyester is present in a proportion of 50% by weight, and the polymerization is carried out by a bulk polymerization method substantially in the absence of a solvent.

When polymerization is carried out in the presence of the polyester of general formula B (hereinafter abbreviated as polyester B), the orientation is significantly suppressed, the appearance of the molded product is good, and the shrinkage rate is different even without a filler. The orientation was small. Furthermore, the mechanical properties and heat resistance are
Not only is it comparable to this, but its fluidity (moldability) has also been improved. As a result, effects such as a significant improvement in the weld portion strength 1y of the molded product were also observed.

The cause of this effect due to polymerization at °C in the presence of polyester B is not clear, but it may be due to the polymerization temperature of the aromatic polyester when polymerized in the presence of polyester B or the molding process of the resulting polymer. The temperature is below the melting point of polyester B, and structurally, ζ also has a similar still structure; from this point of view, polyester B can be used as a filler with good wettability at °C and completely aromatic. It is also thought that it is uniformly dispersed in polyester A and suppresses orientation due to its effect as a filler.Or?
Lyester B is produced by transesterification during the polymerization reaction (
It is also possible that it is incorporated into the main chain of the fully aromatic polyester (although it is thought that only a portion of it is considered, considering the melting point and polymerization temperature). This will also result in a well-wetted interior of polyester B and wholly aromatic polyester A.

Polyester B must be present during the polymerization of wholly aromatic polyester A. Simply blending polyester B with fully aromatic polyester 8 does not improve moldability or orientation problems. This travel cause is thought to be due to the occurrence of even-dispersion events.

The molecular weight of polyester B must also be within a certain range. In general formula B, when p+9 is a low molecular weight of less than 10, the effect is less than when p+9 is less than 10. If the molecular weight is low, it may be sufficiently incorporated into the main chain through transesterification during the polymerization reaction and may not be effective as a "good wettability" filler. The molecular weight of polyester B is a value determined by the terminal group quantitative method, but when the degree of polymerization exceeds 1000, the quantitative accuracy decreases, and it is difficult to understand how it corresponds to the effect.

The amount of polyester B used during the polymerization of the wholly aromatic polyester needs to be 5 to 50% by weight of the final polymer. Below this range, the effect is insufficient.

Further, the polymerization must be carried out by a bulk polymerization method in which substantially no solvent is present.

Methods for producing aromatic pre-2-ester include a solution polymerization method in which the polymerization solvent is an organic solvent that dissolves the produced polymer, a suspension polymerization method in which the produced polymer is precipitated from the solvent used for polymerization, and a suspension polymerization method in which the produced polymer is precipitated from the solvent used for polymerization. Bulk polymerization methods are known. In the case of fully aromatic polyesters made from terephthalic acid, isophthalic acid, etc. (1%1) from hydroxybenzoic acid and 4.4''-dihydroxydiphenyl, no solvent has been found to date that can dissolve them. Therefore, the solution polymerization method is preferable.High boiling point solvents such as hydrogenated terphenyl, diphenyl ether, and diphenyl compounds are used in the suspension polymerization method, but the removal, recovery, and cost savings of these solvents are difficult. Although the bulk polymerization method is the most superior polymerization method, it is not often applied to the production of aromatic polyesters. Compared to lucid aliphatic polyesters such as Crate, C aromatic polyesters have a higher melting point (
This is because high temperatures are required to maintain the molten state, and the coloring of the polymer deteriorates significantly, reducing the value of C as a product. If this problem of blue color deterioration is solved, it will be a process that can satisfy both polymer quality and red color economy, and it will have great industrial significance.

The inventors 1. H: When producing fully aromatic polyester,
If polyester B is present in the polymerization reaction system and the polymerization is carried out by a bulk polymerization method in which this solvent is not substantially present, an aromatic polyester with less color deterioration can be obtained, and also without the presence of polyester B (polymerization). Even with the presence of polyester B, the fully aromatic polyester obtained by this method (such as a suspension polymerization method) has better moldability and moldability than aromatic polyesters obtained by other methods (for example, suspension polymerization).
It has been found that a polymer with excellent fluidity, less orientation, and excellent physical properties can be obtained.

The components of the wholly aromatic polyester used in the present invention 1 include, for example, f-hydroxybenzoic acid, metahydroxybenzoic acid, terephthalic acid, isophthalic acid, hydroquinone, reso-Jvsyn, 4,41-dihydroxy-diphenyl, 4゜4 '-Dihydroxydiphenyl ether, 4'-dihydroxydiphenyl sulfone, 4'-4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxybenzophenone, and derivatives thereof can be used.

Among these combinations, combinations of parahydroxybenzoic acid or its ester, terephthalic acid or its ester, and 4,4'-dihydroxydiphenyl or its ester are sometimes preferred.

The aromatic polyester used in the polymerization of wholly aromatic polyester has the general formula H: (wherein p+q is between 10 and 1000 (7), It is obtained from acids or derivatives thereof.This polyester can also be obtained by suspension polymerization or bulk polymerization, but those obtained by bulk polymerization are preferred.

As the method for polymerizing the aromatic polyester of the present invention, a bulk polymerization method is used, and as the ψ charge collection method, any generally known method may be used.

For example, there is a method in which a compound for forming a wholly aromatic polyester represented by the general formula B and an aromatic polyester represented by the general formula B are simultaneously charged into a reaction tank. Thereafter, the polymerization reaction is carried out by heating, and the polymerization reaction is carried out at about 200 to 400°C, preferably 250 to 850°C, under normal pressure or reduced pressure, in an inert gas atmosphere. It is also possible to proceed with the polymerization using a catalyst whose residue does not adversely affect the physical properties of the polymer or whose activity can be rendered inactive by simple treatment.

A more preferred bulk polymerization method involves polymerization at a polymerization temperature.
The polymerization is continued by constantly applying shearing force to the resulting polymer so that the polymer does not solidify, and without solidifying the polymer (until substantially all of the polymer is solidified in a polydisperse state). The maximum temperature that can be used depends in part on the boiling point and decomposition point of the monomer, oligomer, or polymer used.

Condensation is initially carried out at a relatively low temperature, and as the condensation progresses, the temperature is increased. Polymerization is carried out initially at a temperature of 180 to 250C, then at a temperature If of 250 to 880C, preferably at 800 to 860C under heavy pressure or reduced pressure. Once C has become a solid polydisperse, it is possible to raise the temperature while considering its fusion temperature and decomposition temperature8.
Polymerization is carried out at 00-400°C, preferably 810-870°C.

Further, as long as this polymerization wettability is below the decomposition temperature threshold and below the fusion temperature, the higher the polymerization wetting temperature is, the faster the reaction rate will be.

Alternatively, a compound for forming a fully aromatic polyester represented by general formula A and an aromatic polyester represented by general formula B may be simultaneously charged into the first reaction tank, and polycondensation/polyester is prepared. to produce a polymer and a second
A method of transferring to a reaction tank and increasing the molecular weight is also used. 1st
The prepolymer produced in the reaction tank is taken out in a molten state, pulverized and homogenized at °C.Then, the prepolymer is made into a high molecular weight in a second reaction tank and has a good C temperature. It can be made into a high molecular weight in a reaction tank with a good temperature at °C.

Alternatively, as yet another method, instead of charging the aromatic polyester represented by the general formula B from the beginning, there is a method in which the aromatic polyester represented by the general formula B is added sequentially during the polymerization reaction of the fully aromatic polyester represented by the formula A. . If this method is used first
, when carrying out two-stage polymerization using the second reaction tank, the first
It is preferable to add them sequentially during polymerization in a reaction tank.

The aromatic polyester thus subjected to t4 is a polymer with little coloring, excellent moldability, and excellent heat resistance, mechanical properties, and the like.

The aromatic polyester obtained by C according to the present invention does not contain fillers (C also sufficiently satisfies mechanical properties and other physical properties, but if necessary, stabilizers,
Colorant, various filling IF! ? "Communication additives added to plastics can be added to the extent that they do not impair the properties of the polymer. The filler C can be an inorganic material such as silica, powdered quartz or sand, fumed silica, silicon carbide, aluminum oxide, glass lN4m, etc. Materials and heat resistant organic pigments can be used.

The polymer obtained by the present invention can be molded into molded products, films, sheets, etc. by methods such as press molding, injection molding, and extrusion molding, such as mechanical parts, electric 0M parts, motor parts, various containers, and packaging. C1 is widely used in fields where high performance is required, such as engineering plastic materials.

The present invention will be explained below with reference examples, examples, and comparative examples, but these are illustrative and are not intended to be limiting.

Reference Example 1 Polymerization W41 having an anchor-type stirring blade and a small clearance between the wall of the polymerization tank and the stirring blade.Hydroxybenzoic acid 2072f (15 mol) Acetic anhydride 1685f
(16.5 mol) was added.

The mixture was heated to 150° C. in 1 hour while stirring under a nitrogen gas atmosphere, and refluxed for 8 hours at this temperature. Thereafter, the acetic acid contained as a result of the reaction was distilled off while raising the temperature, and the
The temperature was raised to ℃. Polymerization was further continued for 1 hour with strong stirring, and then gradually cooled and strong stirring was continued until 200° C., after which the polymerized product was taken out of the tank. The amount collected is 1740
V (96.7% of theory). After pulverizing this, the powder was transferred to a hot Arudenso rotary oven, the entire system was rotated under a nitrogen stream, the powder was thoroughly stirred, and the temperature was gradually raised to 870'C over 6 hours, and then treated at 870'C for 8 hours. After cooling, the powder was taken out at 200°C.The obtained powder was heated at 1680f.

The number average degree of polymerization of this polyester determined by terminal group determination method I was 85.

Reference Example 2 Into the same apparatus as in Reference Example 1, 926 f (9.0 mol) of phenyl hydroxybenzoate and 11.0 mol of metahydroxybenzoic acid (phenylbenzoate L'214t) were charged. The temperature was raised while stirring under a nitrogen gas atmosphere, resulting in reaction eyelids and 98.8% of the stoichiometric amount was obtained. The number average degree of polymerization of this polyester was determined to be 25 by an end group assay. - Example 1 In a device similar to Reference Example 1, rose hydroxybenzoic acid 91
0.8f (6.6 mol), terephthalic acid 647.8f (
8,8 mol), 4,41-dihydroxydiphenyl 61
8.8 f (' 8.8 mol), 458.72 of the polymer obtained in Reference Example 1 (20% by weight of the final produced polymer)
) and acetic anhydride 1618.2F (15,8
mole) was added.

The mixture was heated to 160° C. in 1 hour while stirring under a nitrogen gas atmosphere, and refluxed at this temperature for 8 hours. Thereafter, the acetic acid contained as a result of the reaction was distilled off while raising the temperature, and the temperature was raised to 810°C under high shear. Polymerization was continued for 2 hours with further strong stirring, and then cooled to 200°C to produce polymer 2168f (
94.3% of theory) was obtained.

After pulverizing this, it was transferred to an aluminum rotary oven, and the entire system was rotated under a nitrogen stream, and the temperature was gradually raised to 820°C over 6 hours while thoroughly stirring the powder.
After being treated at 0°C for 8 hours, it was cooled and the powder was taken out at 200°C.

C cylinder temperature 1 using diameter 99aw1L/D~28)
After granulation at f850°C and screw rotation speed 50 rpm, injection molding machine Neomat N47/2 manufactured by Sumitomo Heavy Industries was used.
8 made the injection rear shape. Using various molds, dumbbell-shaped test pieces, Izot impact damage test pieces, weld part strength test pieces, etc. were molded, and the physical properties of each were measured.

The shape results are shown in Table 1-ζ. The orientation of the finished product surface is suppressed,
The appearance is also smooth. It is also believed that the strength of the weld portion is increased and the fluidity is improved. Comparative examples 1 to 8
The results are also shown.

Comparative Example 1 In Example 1, 1. The same procedure as Example 1 was carried out except that the polyester obtained in Reference Example 1 was not used at all.
Polymerization and post-treatment gave polyester 1745f (95.1% of theory). This is the same as in Example 1.
This was granulated and injection molded. The results are shown in Table 1+. Orientation was observed, and the strength of the weld portion was low (inferior to Example 1). Also, the high tensile strength and Izot impact values are thought to be due to orientation.

Comparative Example 2 Polyester 800f1 obtained in Comparative Example 1 Reference Example 1
200 tons of the obtained polyester were mixed and stirred using a super mixer. The obtained polymer was granulated and molded in the same manner as in Example 1. The results are shown in Table 1. Compared to Example 1, the physical properties are lower and the surface of the molded product is non-uniform.

Comparative example 8 This comparative example was carried out using the suspension polymerization method.

Paraacetoxybenzoic acid 900? (5.0 mol), terephthalic acid 415f (2.5 mol), 4,41-dihydroxydiphenyl-diacetylated product 675f (2.5 mol), polyester obtained in Reference Example 1 847.5 t
(corresponding to 20% by weight of the final polymer) and Santotherm 66 (Mitsubishi Monsanto Chemical Co., Ltd.) 14009 as a high boiling point solvent were placed in the reactor, and the mixture was stirred constantly in a nitrogen gas atmosphere for 1 hour. So 180
The mixture was heated to 820°C over a further 1 to 8 hours. Stirring was still continued at 820° C. for 16 hours, and a slurry was formed by heating at 840° C. for 8 hours. The reaction mixture was allowed to cool, and 100 of Cl and Santotherm 66 were added thereto to bring the temperature to 70°C. 1 part of acetone
The slurry was filtered once, and the powder was subjected to Soxhlet extraction using an acetone filter to remove Santotherm 66. This powder was dried under reduced pressure at 1-10°C for 5 hours, and then transferred to a theoretical amount of polymer 15489 under a nitrogen atmosphere. It took 6 hours to gradually raise the temperature to ℃,
After maintaining this temperature for 2 hours, it was cooled to 200°C and the powder was taken out. This polymer was granulated using a strainer and injection molded in the same manner as in Example 1. The results are shown in Table II.

Orientation was observed in the molded product, and the physical property values were lower than those of Example 1.

-L? ! − The final polymer is l-f.

The respective polymers were obtained by polymerization in such proportions as 20.80.40.50% by weight. These were granulated and molded in the same manner as in Example 1 to obtain various physical property values.

The results are shown in Table 2. For comparison, a case where the amount of polymer present is 0.60% by weight is also shown. The molding shrinkage rate was determined as the shrinkage rate (%) in the machine axis direction (MD) and the direction perpendicular to the machine axis ('l' D ) by molding a shrink plate and measuring its dimensions. The molded area V of each polymer in the table represents the optimum molded area It (C! & molding temperature considered appropriate from the balance of characteristic values).

The presence of polyester improves the appearance and significantly increases the strength of the weld. Furthermore, the anisotropy of molding shrinkage rate (difference between MD and TD) becomes smaller,
It is thought that the orientation is relaxed.

At 60%, mechanical strength is poor.

Example 8 The polymer obtained in Reference Example 2 was used as the final polymer 20
Example 1 except that it was made to exist in a proportion that would be % heavy dragon
The subsequent operations were carried out in the same manner as above to obtain an aromatic polyester. This product was granulated and molded, and various physical properties were measured, and the results are shown in Table 11.

Claims (1)

[Claims] General formula A: (wherein X is an alkyl group of 01 to C4, -U-,8.-
80g+, -8- or -CO-, and m and n are 0 or l. The d:e ratio is in the range 1:1 to 10:l and the elfO ratio is between 9:lO and lO:9. Furthermore, the substituents on the aromatic ring in the above formula are in para or meta positions with respect to each other. ) During the production of a fully aromatic polyester prepared by the general formula B:
1. A method for producing an aromatic polyester, which is characterized in that the aromatic polyester is present in such a proportion that the aromatic polyester is present, and the polymerization is carried out by a bulk polymerization method in which substantially no solvent is present.