JPH0699550B2 - Method for producing aromatic polyester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a continuous method for producing a heat-resistant aromatic polyester.

<Problems to be Solved by Conventional Techniques and Inventions> In recent years, aromatic polyesters whose constituent units are mostly formed of aromatic compounds have been found to have heat resistance, solvent resistance, radiation resistance, mechanical properties, and electrical properties. It is used in various industrial materials because of its excellent characteristics.

Suspension polymerization method, interfacial polymerization method, solution polymerization method, bulk polymerization method and the like are known as methods for producing an aromatic polyester, but the former three methods are post-treatments such as solvent removal, polymer washing,
There is a problem of wastewater load, and bulk polymerization has a problem of thermal stability of the polymer, so that there is a problem in economically obtaining a polymer of uniform quality.

<Means for Solving Problems> That is, according to the present invention, in producing an aromatic polyester by a condensation reaction, the reaction is carried out in two or more stages, and each reaction stage uses an independent tank, The present invention relates to a method for producing an aromatic polyester characterized in that a reaction vessel having a horizontal stirring blade is used as a reaction vessel and a reaction vessel before it, and the aromatic polyester is taken out from the final reaction vessel in a molten state.

The aromatic polyester in the present invention is an aromatic hydroxycarboxylic acid containing 50 mol% or more of p-hydroxybenzoic acid and / or an ester-forming derivative of the aromatic hydroxycarboxylic acid, and an aromatic dicarboxylic acid and / or an aromatic dicarboxylic acid. Ester-forming derivative and aromatic dihydroxy compound and / or ester-forming derivative of aromatic dihydroxy compound (provided that the molar ratio of: and the molar ratio of: are both
It is 1: 0 to 1: 4. ) Is obtained by a condensation reaction. This polyester was derived from p-hydroxybenzoic acid. Since it is a base, it is crystalline and has excellent heat resistance, solvent resistance and mechanical properties.

Specific examples of p-hydroxybenzoic acid, m-hydroxybenzoic acid, p- (4-hydroxyphenyl) benzoic acid, 2-hydroxy-6-naphthoic acid, 2-hydroxy-7-naphthoic acid, 1-hydroxy. Examples thereof include ester-forming derivatives such as -4-naphthoic acid, 1-hydroxy-5-naphthoic acid, p-acetoxybenzoic acid, and phenyl p-hydroxybenzoate.

Specific examples of terephthalic acid, isophthalic acid, 4,
4'-dicarboxydiphenyl, 2,6-dicarboxynaphthalene, 2,7-dicarboxynaphthalene, 1,5-dicarboxynaphthalene, 1,2-bis (4-carboxyphenoxy) ethane, 1,4-dicarboxy Examples thereof include naphthalene and ester-forming derivatives such as dimethyl terephthalate, diphenyl terephthalate, and dichloride terephthalate.

Examples of are hydroquinone, chlorohydroquinone,
Methylhydroquinone, phenylhydroquinone, resorcin, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenyl ether, 4,
4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfide, 2,2-bis (4-hydroxyphenyl) propane, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, Examples thereof include 1,4-dihydroxynaphthalene and ester-forming derivatives such as 1,4-diacetoxybenzene.

The crystallinity of the obtained polymer, within the range not impairing the physical properties such as heat resistance, trans-1,4-dicarboxycyclohexane, ethylene glycol, trans-1,4-dihydroxycyclohexane, alicyclic ring such as xylylenediol. Copolymerization of group or aliphatic compounds can be used.

In the present invention, the reaction is carried out in two or more steps. For example, in the first stage, oligomer synthesis is performed, and in the second and subsequent stages, higher molecular weight oligomer is produced.

Then, the reaction of each stage is carried out in an independent tank so that the polymer of each stage is not mixed and the quality of the final polymer is not deteriorated.

Although this condensation reaction is carried out continuously, it should be noted that back mixing (backflow) does not occur. For this reason, for the final reaction tank and the reaction tank before it, use reaction tanks with horizontal stirring blades, and carry out the reaction uniformly in these, and at least in the latter half of the final reaction tank, the polymer is in a molten state. Are uniformly mixed with each other, and the aromatic polyester is taken out in a molten state from the final reaction tank. Thus good quality polymers can be obtained.

In each stage of the reaction, the atmosphere may be an inert gas and the pressure may be atmospheric pressure, slightly pressurized system or reduced pressure system. A method is preferred in which the first half is performed at normal pressure and the second half is performed under reduced pressure.

Note that it is not necessary to use a horizontal reaction tank before two steps from the final reaction tank. The reaction temperature can be arbitrarily selected.

To the condensation reaction system, it is necessary to add a solvent, a lubricant, various stabilizers, additives, etc. and optionally a polymerization catalyst that does not adversely affect the quality of the polymer even if it is removed or remains in the final reaction tank. You can also Further, a filler can be added.

As a reaction tank having a horizontal stirring blade used in the final reaction tank and the reaction tank before it, the stirring shaft has a single shaft or two shafts,
It is preferable to have blades having a vertical or angled axis, a scraping plate, or the like, and in some cases, a baffle plate may be used on the tank wall. A partition plate may be provided in the same tank to improve the mixing performance and prevent backflow.

The tank is equipped with a jacket and is heated by a catalyst, gas or a heater. However, for the purpose of uniform heating, it is preferable to heat the stirring shaft, blades, scraping plate, baffle plate and the like in the same manner.

Polyester is taken out from the final reaction tank in a molten state, but the taken out melted body is cut as it is with a hot cutter, or it is a granular, sharty, fibrous intermediate or the final product by an extruder or gap pump or a combination thereof. It can be a processed product. It is also possible to mix a filler, additives, etc. in an extruder and co-extrude.

<Effect of the Invention> By using the present invention, a uniform and high-quality aromatic polyester can be continuously and economically produced. Further, according to this method, the stirring load during polymerization is small, and there is almost no adhesion of the polymer to the tank wall, blades, etc. In some cases, it is possible to consistently adopt the process up to the final product, and it is possible to prevent the inclusion of dust and contaminants.

<Example> (Example 1) Five reaction tanks connected in series were used.

The first reaction tank is a monomer reaction tank, which is a vertical reaction tank with a capacity of 50 and an anchor type stirring blade.

The second and third reaction tanks are buffer tanks and are vertical reaction tanks with a capacity of 100 and anchor type stirring blades.

The fourth reaction tank is the first polymerization tank, which is a horizontal tubular reaction tank having a uniaxial stirring shaft with blades. The wings attached to the shaft are fan-shaped wings,
If you take a cross section perpendicular to the axis where the wing is located, 1/3 of the cross section is occupied by the projected part of the wing. The blades are offset by 10 ° with respect to the direction of movement of the shaft, and a 4m-long spiral forms two spirals so that the reactants travel in the axial direction. The inside of the shaft and the outside of the tank are heated by a heat medium.

The fifth reaction tank is a horizontal cylindrical stirring tank with a biaxial stirring shaft.
With the shaft, the blade comes out on the shaft and a scraping plate is attached to the tip of the blade so that the entire tank wall can be cleaned. The axis of this tank,
The blades and the outside of the tank are heated with a heat medium.

The polymer discharge hole of the fifth reaction tank is connected to the vent extruder.

In the first reaction tank, p-hydroxybenzoic acid 4,140 g (30 mol), terephthalic acid 2490 g (15 mol), 2,6-dihydroxynaphthalene 2,420 g (15.1 mol), acetic anhydride 6,732 g (66 mol)
Mol) and xylene 10 were added, and the mixture was reacted under a nitrogen atmosphere under reflux for 3 hours and transferred to a second reaction tank. After the transfer, the same amount of the same thing was charged in the first reaction tank and reacted.

The second reaction tank was kept warm, and the reactants in the first reaction tank were mixed by stirring. In the second reaction tank, the contents were stirred and mixed in such a manner that the liquid level was kept constant with a cycle of 4 to 5 hours, and the mixed contents were continuously transferred to the third reaction tank.

In the third reaction tank, xylene, acetic acid by-product and acetic anhydride were distilled and discharged, and the contents were intermittently transferred to the fourth reaction tank in a fixed amount.

In the fourth reaction tank, the heating portion from the outside of the tank is divided into six parts in the axial direction, and each is heated to 170, 200, 230, 260, 290, 320 ° C, and the heating medium at 170 ° C flows through the reaction shaft. The inside of the tank is a nitrogen atmosphere and is at normal pressure. The rotation of the shaft and the blades causes the raw material in the reaction vessel to undergo condensation and a high degree of polymerization, resulting in an opaque uniform melt at the outlet.

The melt was then transferred to the fifth reactor and heated at 320 ° C from the vessel walls, shafts, and blades. There were gap pumps at the inlet and outlet of the fifth reaction tank to control the residence time. The pressure of the fifth reaction tank is set to 100 mmHg.

The polymers at the outlets of the fourth and fifth reaction tanks are both in a molten state and their "flow temperatures" are 27
The temperature was 6 ° C and 325 ° C. (Note that the "particle size temperature" is 48,000 poise when the resin flows at a pressure of 100 kg / cm ² from a nozzle with a diameter of 1 mm and a flow of 10 mm using a Shimadzu CFT-500 flow tester.
Indicates the temperature to be set. ) The polymer discharged from the fifth reaction tank was fed into the extruder in a molten state and granulated. The "flow temperature" of the granulated product was 331 ° C.

The pellets were molded with an injection molding machine Neomat manufactured by Sumitomo Heavy Industries. The cylinder temperature was 350 ° C and the mold temperature was 120 ° C.

The tensile strength of this molded product is 1,850 Kg / cm ² , and the heat distortion temperature (1
8.6 Kg / cm ² ) showed a weight loss at 262 ° C and 300 ° C of 0.24% after holding for 1 hour, which was excellent in heat resistance and mechanical properties.

In addition, the same evaluation was performed on the extrudates 1,3,6,8 hours after the formation of the reaction product, but it was found that the physical properties similar to the above could be obtained and the quality was stable. .

Claims (1)

[Claims] 1. An aromatic hydroxycarboxylic acid containing p-hydroxybenzoic acid in an amount of 50 mol% or more and / or an ester-forming derivative of the aromatic hydroxycarboxylic acid. Aromatic dicarboxylic acid and / or ester forming property of aromatic dicarboxylic acid. Derivatives and aromatic dihydroxy compounds and / or ester-forming derivatives of aromatic dihydroxy compounds (provided that the molar ratio of: and the molar ratio of: are both
It is 1: 0 to 1: 4. ) In the method for producing an aromatic polyester by a condensation reaction, the reaction is carried out in two or more steps, each reaction step uses an independent tank, and horizontal stirring is used for the final reaction tank and the reaction tank before it. A method for producing an aromatic polyester, characterized in that a reaction vessel having blades is used and the aromatic polyester is taken out in a molten state from the final reaction vessel.