JPS5834493B2 - Polyester manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing polyester, and more particularly to polybutylene terephthalate (hereinafter referred to as "P B TJ").

) is related to the production method by solid phase polymerization**.

Solid-phase polymerization is conventionally known as a method for producing polyester with a high degree of polymerization, but solid-phase polymerization is carried out under vacuum or under an inert gas flow, which is often disadvantageous in terms of equipment and economics. .

The present inventors conducted research to eliminate such disadvantages, and as a result, they arrived at the present invention.

That is, the present invention uses a phenol compound represented by the general formula (%) with an intrinsic viscosity of 0.5 to 1.
The present invention provides a method for producing a polyester, characterized in that a composition obtained by adding polybutylene terephthalate (1) to the polybutylene terephthalate until the end of the melting reaction is solid-phase polymerized.

PBT as used in the present invention may contain up to 10 moles of other copolymer components.

These copolymerized components include glycol components such as ethylene glycol, propylene glycol, and hexamethylene glycol, dicarboxylic acids such as isophthalic acid, knack dicarboxylic acid, and adipic acid, pentaerythritol, trimethylolpropane, trimellitic acid, and pyromellitic acid. Examples include polyfunctional compounds such as acids.

Terephthalic acid and 1,4-butanediol (hereinafter referred to as “1,4
It's called 8Gl.

) is usually carried out at a ratio of 1 to 5 moles of 1.48G to 1 mole of terephthalic acid at 200 °C under normal pressure or increased pressure.
It is carried out at a temperature of ~240'C with continuous removal of the water produced.

At this time, it is often advantageous if a catalyst such as a titanium compound is present.

The transesterification reaction is usually carried out using dimethyl terephthalate (hereinafter referred to as
“It’s called DMTJ.

) and 1.48G in a molar ratio of 1:1 to 1:2 under normal pressure and at a temperature of 150 to 220°C while continuously removing generated methanol.

A catalyst is required to obtain a practical reaction rate, and suitable catalysts include titanium compounds, lead oxide, lead acetate, zinc oxide, zinc acetate, and manganese acetate.

Particularly suitable are organic titanates and titanium tetrachloride hydrolysates.

The amount used is 10 to 11000 pp as Ti vs. polymer,
Preferably it is 30 to 200 ppm.

It is preferable to add the catalyst several times or more during the reaction.

The polycondensation reaction is obtained by the above-mentioned esterification reaction or transesterification reaction, and the product is subjected to melt polycondensation at 200 to 260°C while reducing the pressure of the reaction system and continuously removing 1.48G until the desired degree of polymerization is obtained. to obtain a prepolymer.

A catalyst is required to obtain a practical reaction rate during the polycondensation reaction.

For example, suitable organic titanates such as tetrabutyl titanate, tetrapropyl titanate, tetraethyl titanate, and tetramethyl titanate and their daily water decomposition products, daily water decomposition products of titanium tetrachloride and titanium sulfate, titanium potassium fluoride, Examples include inorganic titanium compounds such as titanium zinc fluoride and titanium cobalt fluoride, and titanium compounds known as polyester production catalysts such as titanium oxalate and titanium potassium oxalate.

Particularly preferred are hydrolysates of tetrabutyl titanate, tetrapropyl titanate, and titanium tetrachloride.

In addition to the titanium compound catalyst, other color additives such as pigments such as titanium dioxide, and stabilizers such as phosphoric esters may be added.

If the catalyst is used in the esterification or transesterification step, there is no need for further addition during the polycondensation.

Compound (I) may be added at any stage of the prepolymer production reaction process, but it is necessary that the time from addition to completion of the melting reaction be within 6 hours, preferably within 4.5 hours.

The prepolymer of [η)-0.5 to 1.1 obtained by melt polymerization is made into a powder or pellet form, and solid phase polymerization is performed according to a conventional method.

When [η)>1.1 or [η:]<0.5, it is difficult to carry out solid phase polymerization smoothly.

The size of the pellets is preferably 5 or less.

The solid phase polymerization is carried out at 190 to 210°C under air flow and with mixing.

Air may be diluted with nitrogen or the like, but it is most effective to use air as is.

If the temperature is below 190°C, the polymerization rate is too low, and if it is above 210°C, the polymer deteriorates rapidly, so it is not suitable.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example I 100 parts of DMT, 83 parts of 1.48G, and 0.05 part of tetra-n-butyl titanate were placed in a reactor equipped with a rectification column.
The transesterification reaction was carried out at 0°C to 210°C.

Methanol produced during the reaction was distilled out of the reaction system from the rectification column.

Tetra n-butyl titanate 0.02 in 2 hours reaction time
The reaction was completed in 3 hours and 30 minutes.

The obtained monomers were transferred to a polycondensation reactor, and 1-0.02 parts of tetra n-butyl titanate and compound (I) (X = 2
) was added to carry out a polycondensation reaction.

The reaction was carried out by gradually increasing the temperature from 210C to 2500C and reducing the pressure of the system to 250C and 0.2mmHg for 1 hour and 15 minutes.The reaction was then continued at 2500C10 and 2mmHg for up to 2.5 hours until the polymer was 3%9! It was taken out in the form of a pellet with fX3 mm, and [η) = 0.87.

([η] is phenol:tetrachloroethane, 3
(measured at 0°C).

This pellet was subjected to solid phase polymerization in a rotary kiln type solid phase polymerization apparatus at 205 DEG C. for 4 hours without air circulation, resulting in a polymer having [η]=1.35.

Comparative Example 1 A prepolymer was obtained under the same conditions as in Example 1, except that compound I) was not added.

[η)=0.83.

When this was polymerized under the same solid phase polymerization conditions as in Example 1,
[η] decreased and was [η)-0.450 Example 2 Under the same conditions as Example 1, except that compound (1) was added at the start of the transesterification reaction, and transesterification Prepolymers were obtained in three ways: when the reaction time was 2 hours, and when the temperature was added at the end of the melt polycondensation reaction.

When the melt polycondensation reaction time was 2 hours and 30 minutes, [η] was 0.
．． 86, 0.87, and 0.83.

This was subjected to solid phase polymerization under the same conditions as Example 1 [η]
were 0.88, 1.20, and 1.37, respectively.

This shows that it is undesirable to take a long time to complete the production of the prepolymer after addition of compound (I).

Example 4 100 parts of terephthalic acid, 120 parts of 1.48G, and 0.01 part of titanium tetrachloride hydrolyzate were charged into a reactor, and the temperature was raised to 2300C while distilling off water.

The reaction system became transparent in 120 minutes.

This was transferred to a polycondensation reactor, 0.04 parts of compound (I) (Xl) was added, and polymerization was carried out under the same conditions as the melt polycondensation conditions of Example 1. [η]= A prepolymer of 0.85 was obtained.

This was subjected to solid phase polymerization under the same conditions as Example 1 [η] 1.36
of polymer was obtained.

Claims (1)

[Claims] 1. A phenol compound represented by the general formula (in the formula, X represents an integer of 1 to 4) having an intrinsic viscosity of 0.5 to 1
．． 1. A method for producing polyester, which comprises solid-phase polymerizing a composition obtained by adding polybutylene terephthalate in step 1 before the melting reaction is completed.