JPS61103925A - Production of high-molecular weight polyester - Google Patents

Abstract

PURPOSE:To accomplish easy production of high-molecular weight polyester in a short time by leaving with a constant thickness a high-polymerization degree polyester at rest on a plate followed by heating under a vacuum to expand it in a form similar to roast rice cake to substantially thin the polymer layer. CONSTITUTION:A polyester with an intrinsic viscosity >=0.6 consisting of aromatic dicarboxylic acid component and aliphatic and/or aliphatic diol component(s) is left at rest with a thickness 0.1-10mm on a plate followed by heating to a temperature higher than the melting point but lower than the decomposition temperature of said polyester under a high vacuum <=200Pa to cause reaction to bring its intrinsic viscosity to >=1. The plate to be used is of movable type with the contact surface with said polyester consisting of polyfluoroethylene polymer, being designed to feed the polyester to one end thereof. The original polyester with an intrinsic viscosity >=0.6 is incorporated, in advance, with such a compound as to continuously generate, during the reaction, gaseous substance preventing the molecular weight of said polyester from dropping (e.g., a polyester from 6-20C aliphatic dicarboxylic acid and ethylene glycol).

Description

Detailed Description of the Invention (&) Technical Field The present invention is a high molecular weight polyester useful as a raw material for fibers, films, and other molded products having excellent physical properties. This invention relates to a method for producing by melt polymerization.

(b) Prior Art It is well known that polyester, represented by polyethylene terephthalate, is used as a raw material for manufacturing fibers, films, and other molded products.

Molecular weight tends to be a major factor influencing the physical properties such as strength of these molded products, and it is desired to increase the molecular weight in order to improve these physical properties.

However, the normally performed polycondensation reaction of deglyfur cleavage is (1) an equilibrium reaction, so the molecular weight can only be increased to a molecular weight corresponding to the glycol partial pressure; (2)
Because decomposition reactions also occur in high-temperature polycondensation reactions, it was thought to be difficult to obtain high-molecular-weight polyesters by melt polymerization.

In order to solve these problems, a solid phase polymerization method in which a polymerization reaction is carried out at a low temperature is generally used. However, the solid phase polymerization method has problems such as the reaction time required, the resulting polymer being difficult to dissolve, and the resulting polymer having an intrinsic viscosity of 1 at most. It is about .4.

In addition, various studies have been made to improve the melt polymerization method to produce high molecular weight polyesters, a typical example of which is the use of chain extenders. However, this method not only requires an expensive chain extender, but also the parts connected by the chain extender may be thermally unstable, and compounds produced by the chain extender may remain in the polymer. This has the disadvantage that it mixes into the ethylene glycol produced as a by-product, making it difficult to recover the ethylene glycol. Further, even if this method is applied, it is difficult to obtain a high molecular weight polyester having a specific gc of 1.8 or more.

[c) Object of the Invention An object of the present invention is to provide a method for producing a high molecular weight water reester using a melt polymerization method.

(dl Solution) As a result of repeated studies by the present inventors to find a method for producing "C" using a melt polymerization method using a high degree of polymerization polyester having an intrinsic viscosity of 1 or more, we found that Polyester I, which has been polymerized by the usual melt polymerization method until its viscosity is considerably high, is placed on a plate to a thickness of 0.1 to 10 Ioi and heated under reduced pressure, causing it to swell like when baking rice cakes. It was discovered that this swelling has the same effect as substantially reducing the thickness of a single layer of polymer, and that a polyester with a high degree of polymerization can be obtained in a short time, leading to the present invention.

(s) Structure of the Invention The present invention consists of polyester having an intrinsic viscosity of 0.6 or more, which is composed of an aromatic dicarboxylic acid component and an aliphatic and/or alicyclic diol component, and is coated on a plate with a thickness of 0.1 to 10 m. Leave it still, 2
A process for producing a polyester with a high degree of polymerization is characterized in that the polyester is subjected to a heating reaction at a temperature higher than the melting point and lower than the decomposition temperature of the polyester under a high vacuum of 00 Pi or less so that the intrinsic viscosity is 1 or higher.

The polyester targeted in this project@ has aromatic dicarboxylic acid as the main acid component, aliphatic glycol and/or
In the case where the main glycol component is an alicyclic diol, the term "mainly" means more than 50 mol. Therefore, less than 50 moles of other ingredients may be included.

In the present invention, the aromatic dicarboxylic acid j refers to a compound in which a carboxylic acid is directly bonded to an aromatic nucleus, such as terephthalic acid, inphthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, etc., and terephthalic acid is particularly preferred. In this BA, "aliphatic glycol" refers to ethylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, etc. Among these, in particular, ethylene glycol, tetramethylene glycol, Hexamethylene glycol is preferably used.

Further, as the alicyclic diol, cyclohexane 9/tanol is preferred.

Examples of the third component that can be copolymerized in the present invention include aromatic dicarboxylic acids other than the main constituent components of the polyester; succinic acid, manic acid; octaric acid, adipic acid, sepacic acid;
Aliphatic dicarboxylic acids such as decanedicarboxylic acid; alicyclic dicarboxylic acids such as hexaterephthalic acid, decalindicarboxylic acid, and tetralindicarboxylic acid; glycolic acid,
p-oxybenzoyl; aliphatic alcohols other than the main constituent components of the polyester such as ethylene glycol, trimethylene glycol, propylene glycol, 1.3-phthanedyl, neopentyl glycol; cyclohexane dimer 5
Alicyclic diols such as - a -l, tricyclodecane dimethyl p-l; hisphenol A, bis7E/ -A S
.

Aromatic diols such as bishydroxyethoxybisphenol A and tetrabromobisphenol A are exemplified.

Such a polyester is a so-called ester in which an aromatic dicarboxylic acid and/or its lower fullkyl ester and a diol are heated in the presence or absence of a catalyst to remove water and/or alfur to produce a diol ester of an aromatic dicarboxylic acid. After carrying out the transesterification reaction and/or the transesterification reaction, the diol is removed by heating to a temperature above the melting point under reduced pressure in the presence of a polymerization catalyst, followed by polycondensation at °C. The polyester obtained at this time has an intrinsic viscosity of 0.6 or more, preferably 0, and an e of 7 to 1.1. If a polyester that does not reach 0.6 is used, it will not swell even when heated on a plate under reduced pressure, and the object of the present invention will not be achieved. A polyester having such a degree of polymerization can be produced by a conventional melt polymerization method. If desired, a solid phase polymerization method may be used, but if a polyester with an intrinsic viscosity as high as possible (as much as possible by a normal melt polymerization method) is produced, it can be applied to the present invention, so do not overdo it at this stage. It is not necessary to have a high intrinsic viscosity. Further, it is preferable that the polyester at this stage has less than half of the terminal carboxyl groups.

The most preferred method of the present invention is to use a terephthalic acid component as the aromatic dicarboxylic acid component, and ethylene glyfur as the diol component, and further to use a gaseous and substantially boriesnarda component under the polymerization conditions.

This method uses polyester containing a compound that continuously generates a substance that does not reduce the molecular weight of the polyester.

The compound to be contained here has, for example, 6 to 20 carbon atoms.
A polyester consisting of an aliphatic dicarboxylic acid component and an ethylene glyfur component, a polyester consisting of an aliphatic oxycarboxylic acid component having 5 to 12 carbon atoms, polystyrene,
Examples include polyoxymethylene. These compounds are preferably mixed or copolymerized into the polyester before carrying out the polymerization method of the present application. The amount of this compound added is 1 to 50% by weight, preferably 2 to 20% by weight, based on the polyester. When the amount is less than this, the effect of addition is small, and when it is added, the effect is not so great and other physical properties tend to deteriorate.

In the present invention, the above-mentioned polyester is placed on a heating plate to a thickness of 0.1 to 10 mm, and heated to a temperature above the melting point under a high vacuum of 200 Pa or less to make the polyester have an intrinsic viscosity of 1 or more. .

The following devices are used here, for example. In other words, it is an apparatus in which a fixed or movable heating plate is installed in a container that can create a high vacuum of 200 Pa or less. This heating plate may be heated by external heat transfer, radiation, etc. Alternatively, the heating plate itself may be heated by placing it in a chamber with a built-in heater, a chamber through which an electric current is passed, or a vibration field. It may be something that It is preferable that such a heating plate is designed so that the temperature of the portion in contact with the polymer is as uniform as possible. This is because the reaction rate changes depending on temperature, so if there is temperature variation, the degree of polymerization of the resulting polyester will vary. This heating plate may be plate-shaped, mesh-shaped, or parallel-shaped. In particular, the surface of the heating plate in contact with the polymer is preferably made of a polyfluoroethylene polymer such as polytetrafluoroethylene. This is to make it easier to peel off the obtained high degree of polymerization polyester from the hot plate.

One or more such heating plates are installed in a container capable of high vacuum. At this time, it is desirable that the distance between the heating plates or between the heating plate and the wall surface be at least 5 times the thickness of the polymer, preferably at least 10 times the thickness of the polymer. This is to prevent the polymer from swelling and coming into contact with other surfaces.

In the present invention, the degree of polymerization is increased by placing the polyester at a thickness of 0.1 to 10 degrees on such a heating plate. This operation of placing the polyester may be carried out either by placing a molten polymer on a heating plate or by placing a solid polymer at ℃. If it is solid, it may be placed in the form of a chip, but it is preferable to place it in the form of a plate because the thickness will be uniform. The thickness when this polyester is placed is 0.1 to 10 layers, preferably 0.5 to 5 layers.If it is thicker than this, there will be a large difference between the upper and lower parts, making it difficult to increase the molecular weight. It is not suitable because it has poor properties and also makes it difficult to peel off the heating plate.

Further, it is preferable to keep the polyester in a dry state before standing still.

The polyester placed on the heating plate is heated at a pressure of 200 Pa or less, preferably 100 Pa or less, above the melting point and below the decomposition temperature, preferably above the melting point and at 220 to 300°C, thereby increasing the molecular weight. At this time, the reaction time depends on the thickness,
Although it is difficult to define it unambiguously because it varies depending on the reaction temperature, type of catalyst, type of polyester, etc., it is usually 1 to 1.
300 minutes, preferably 5 to 120 minutes ・It is important to keep this reaction low (at the final stage, the polyester becomes like a swollen baked rice cake) ・In the solid phase polymerization method of polyester, an inert gas is used. It is possible to increase the molecular weight by flowing it onto the polymer surface, but
In this case, for example, if the reaction is carried out under normal pressure while flowing an inert gas, it is not possible to raise the molecular weight. This seems to be because the polymer does not swell like a baked rice cake.

The thus obtained high molecular weight polyester having an intrinsic viscosity of 1 or more is taken out as it is or after cooling and molded into fibers, films, and other molded products.

’ If you take it out and use it in the form of a lump, compress it to make a polymer with few bubbles, and then press it directly.
・It is preferable to cool it immediately and cut it into chips.

Another method is to dissolve it in a solvent or add a possitive agent to take it out. In this case, one of the preferred methods is to add the molten polymer directly to the solvent or plasticizing agent. Particularly when using a starifying agent that is non-reactive and nonvolatile under polymerization conditions, it is preferable to mix it with the starifying agent under reduced pressure.

According to the present invention, it is possible to obtain a high molecular weight polyester having an intrinsic viscosity of 1 or more, preferably 1.2 or more, more preferably 1.34 or more, which can be used to produce, for example, fibers, films, and other molded products with high tenacity. can be obtained. Further, the obtained polyester may contain stabilizers, inorganic or organic additives, reinforcing agents, etc. without any problem.

Example 1 35 parts of dimethyl terephthalate, 2 parts of ethylene glycol
0 parts, calcium acetate monohydrate 0, 022 parts has an internal temperature of 2
Phosphorous acid 50% after transesterification until 40℃
0.024 parts of aqueous solution of titanium and 4.6 parts of decanecarboxylic acid were added, and after stirring for 10 minutes, 0.025 parts of titanium tetrabutoxide was added, and the mixture was reacted at 240° C. for 30 minutes while removing water. The obtained reaction product was reacted at 275°C while gradually reducing the pressure, and after 6 hours at a final reduced pressure of 70 Pa, a polyester with an intrinsic viscosity of 1.04 was obtained. This polyester was discharged into water to a width of 50 m + a thickness of 2 +
The +n+ grenite was heated at 140°C for 6 hours and placed on a heating plate with a 1m thick polytetrafluoroethylene plate placed on a 3m stainless steel plate at a surface temperature of 265°C. The heating plate was placed in a vacuum container, and while the temperature of the heating plate was maintained at 265° C., a reaction was carried out at 40P& for 90 minutes, and after returning to normal pressure with nitrogen, it was taken out into water and cooled.

The resulting polymer had an intrinsic viscosity of 2.31 measured at 35°C with orthocool phenol.

Also, when I looked through the window during the reaction, I found that the height was about 2 cm.
cm rc @was.

Comparative Example 1 In Example 1, heating was performed to 265°C instead of reducing the pressure.
An attempt was made to polymerize the polymer by flowing the polymer, but the intrinsic viscosity of the polymer obtained after 90 minutes was only 1.23. Further, no swelling was observed when observed during the reaction.

Example 2 In Example 1, decanedicarbone was not added and antimony oxide was used instead of titanium tetrabutoxide.
．． 0.015 parts was added and reacted at 275° C. for 3 hours under reduced pressure to obtain a polyester having an intrinsic viscosity of 0.71, which was then heated in the same apparatus as in Example 1 [reacted at 275° C. and 40 Pa for 2 hours. The intrinsic viscosity of the obtained polyester was 1.35 tbsp, and as a result of observation, it had expanded to 1.6 cIL.

Claims (4)

[Claims] (1) A polyester having an intrinsic viscosity of 0.6 or more and consisting of an aromatic dicarboxylic acid component and an aliphatic and/or alicyclic diol component is placed on a plate to a thickness of 0.1 to 10 mm,
1. A method for producing a high molecular weight polyester, which is characterized in that the intrinsic viscosity of the polyester is increased to 1 or more by heating the polyester under a high vacuum of 0.0 Pa or less to a temperature higher than the melting point and lower than the decomposition temperature. (2) At least the surface of the plate that comes into contact with the polyester is made of a polyfluoroethylene polymer.
1) A method for producing a high molecular weight polyester as described in section 1). (3) A method for producing a high molecular weight polyester according to claim (1) or (2), wherein the plate is movable and the polyester having an intrinsic viscosity of 0.6 or more is supplied to one end of the plate. (4) Claim (1) in which the polyester having an intrinsic viscosity of 0.6 or more contains a compound that continuously generates a gaseous substance under reaction conditions that does not substantially reduce the molecular weight of the polyester. - The method for producing a high molecular weight polyester according to any one of item (3).