JPS6017334B2 - Polyester manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in the manufacturing method of polyester using terephthalic acid and ethylene glycol as main raw materials. This invention relates to a method for producing polyester with excellent titanium dispersibility.

Bis-8-hydroxyethyl terephthalate and/or its low polymer (hereinafter referred to as BHT) is obtained by esterification reaction from terephthalic acid (hereinafter referred to as TPA) and ethylene glycol (hereinafter referred to as EG), and then polycondensed. Polyethylene terephthalate (hereinafter P
The direct polymerization method for producing ET (hereinafter referred to as ET) is well known.

However, the method for manufacturing PET from dimethyl terephthalate (hereinafter referred to as DMT) and EG (hereinafter referred to as DMT)
It has the disadvantages that the whiteness of the polymer color tone is poor and the content of diethylene glycol (hereinafter referred to as DEG) in the polymer is high compared to the PET method. The disadvantage of this method is that the dispersibility of titanium dioxide is poor. This decrease in the whiteness of the polymer color tone lowers the commercial value of fibers, etc., and DEG introduced into the polymer lowers the softening point of the polymer.
Decreases evening heat stability of polymers.

In addition, poor dispersibility of titanium dioxide in the polymer reduces spinnability and drawability, increases the pack internal pressure during iron yarn, causes yarn breakage, and increases the occurrence of fuzz during drawing. Various methods have been proposed to suppress such drawbacks in the direct zero-vehicle system. In other words, as a method for improving the whiteness of the polymer color tone, there is a method of adding a cobalt compound (Jiko Sho 48-33280, Tokkan Sho 48-92496).
) has been proposed.

However, if a large amount of cobalt compound is used, the heat resistance of the polymer decreases, and the inherent viscosity of the paper yarn is significantly decreased, resulting in a drastic decrease in the operability of spinning. On the other hand, as methods for suppressing the formation of DEC, proposed methods include (1) adding an alkali or alkali metal salt, and (2) adding an amine soluble in PET.

However, these compounds need to be added at the initial stage of the esterification reaction, and the compounds mentioned in (2) generate insoluble foreign matter in the polymer, which deteriorates the paper thread properties and drawability.

In addition, the compound in ■ does not have such a drawback, but
It has the disadvantage of reduced whiteness. Furthermore, as a method of improving the dispersibility of titanium dioxide in a polymer, a method of adding calcium, strontium, barium, tin, or rare metal acetates has been proposed.

(Japanese Patent Application Laid-Open No. 48-66692). However, this method was also found to be undesirable, as it resulted in the formation of insoluble foreign matter in the polymer.

Therefore, the present inventors conducted studies aimed at the above-mentioned direct polymerization method, improving the whiteness of the polymer, reducing DEG, and improving the dispersibility of titanium dioxide, and as a result, they arrived at the present invention. That is, in the present invention, when producing a titanium dioxide-containing polyester from a dicarboxylic acid mainly consisting of terephthalic acid and a glycol mainly consisting of ethylene glycol, terephthalic acid converts 4-carboxybenzaldehyde into 1
A terephthalic acid containing 0 to 100 pseudopm, and after esterification, a phosphorus compound satisfying the formula {1', ■ is added, and within 2 to 15 minutes after addition of the phosphorus compound '1)
This is a method for producing polyester characterized by adding a cobalt compound and an antimony compound satisfying the formula ~{3l.

−11≦P−0.5 father o≦25 {
1}167≦Sb≦3. Honju 210
■5≦Co≦0.0 snake BA+30
[3' The esterification reaction of the present invention may be carried out by any method, but dicarboxylic acid and glycol are continuously added to a system in which BHT is present in an amount of 50 to 15% by weight based on the added dicarboxylic acid. Alternatively, an intermittent supply method is most preferable in terms of polymer whiteness and DEG content in the polymer.

The BHT may partially include a portion consisting of components other than TPA residues and EG groups.

Further, this BHT may be obtained by any method, but it is preferable to adopt a method in which the esterification reaction product of the present invention is used as it is.

Of course, the slurry of TPA and EG supplied in the present invention may also partially contain other brewing ingredients and glycol ingredients.

The molar ratio of EG/TPA is preferably 1.05 to 1.5,
Particularly preferably, it is 1.10 to 1.30. Further, the esterification reaction may be carried out under normal pressure or under increased pressure, but the gauge pressure is preferably 0.8 kg/mass or less, most preferably 0.45 k9/mass or less. That is, if the reaction is carried out under pressure, the esterification reaction time will generally be shortened, but if the gauge pressure is greater than 0.8 k9/ground, the DEG production reaction will be promoted, which is not preferable. The reaction temperature for esterification is 200℃~2
60 pm C is preferable, and 22 pm to 250 qo is more preferable. If the reaction temperature is less than 20 mm, the reaction time will be long, and if it exceeds 260 mm, the DEC will increase and the reaction product will be likely to be colored, which is not preferred. A phosphorus compound that satisfies the formulas '1} and [2} is added to the BHT esterified in this way, and after the addition of the phosphorus compound, 2 to 18
The object of the present invention can be achieved by adding a cobalt compound and an antimony compound satisfying formulas '1) to [31] within a minute, preferably 4 to 1 minute. The phosphorus compounds used in the present invention include, for example, phosphoric acid, esters of phosphoric acid, phosphorous acid, and esters of phosphoric acid, but from the viewpoint of polymer whiteness, phosphoric acid, partial methyl esters of phosphoric acid, trimethyl phosphate, etc. is preferred, and phosphoric acid is particularly preferred.

On the other hand, cobalt compounds include salts of inorganic acids and organic acid salts such as acetates, and cobalt acetate is particularly preferred.

Antimony compounds include oxides such as antimony trioxide, oxides such as antimony trifluoride, inorganic acid salts such as antimony difluoride, and organic acid salts such as antimony acetate, and among these, antimony trioxide is the most preferred.

The amounts of these phosphorus compounds, cobalt compounds, and antimony compounds must satisfy formulas (1) to '3'. Outside these ranges, the whiteness of the polymer may be insufficient or The effect of inhibiting DEC generation may be insufficient, or the dispersibility of titanium dioxide in the polymer may be insufficient.If [P-0.5*o] is less than -lippm, the heat resistance of the polymer may be insufficient. If it exceeds 25 ppm, the whiteness of the polymer will be insufficient, the effect of suppressing DEC generation in the polymer, and the dispersibility of titanium dioxide in the polymer will be poor.

Moreover, the amount of Sb [3. If it exceeds 1210 ppm, the whiteness and heat resistance of the polymer will be insufficient.

If the amount of Sb is less than 167 ppm, the polycondensation reaction will be insufficient.

When the amount of Co added is 5 ppm, the polymer whiteness, the DEG suppressing effect, and the dispersibility of titanium dioxide are insufficient.
If it exceeds 09.09.FBA130) ppm, unportable foreign substances are generated in the polymer and the weaving properties and stretchability are reduced.

Further, among these ranges, more preferable ranges are as follows.

OSP-0.53Cos15
{41167miSbS3.2P+210
[515 MiCos0.0 Cape BA+10
The timing of addition of cobalt compounds and antimony compounds is that if the time is less than 2 minutes after addition of the phosphorus compound, cobalt foreign matter will be generated due to the interaction of the cobalt compound and antimony compound with the phosphorus compound, and titanium dioxide will be agglomerated violently. The whiteness of the polymer decreases, the amount of DEG in the polymer increases, and the dispersibility of titanium becomes poor, making it impossible to achieve the object of the present invention.

Further, if a cobalt compound or an antimony compound is added before adding a phosphorus compound, the whiteness of the polymer decreases, making it impossible to achieve the object of the present invention. As for the method of adding the cobalt compound and antimony compound, it is preferable to add them in the form of a slurry or solution of EG because if they are added as they are, they tend to become foreign substances. Furthermore, it is preferable to separately add a phosphorus compound.

That is, if the phosphorus compound and these compounds are added through the same port, a large amount of metallic foreign matter will be generated and block the addition port, so it is preferable to add them separately. The most preferable method for adding the phosphorus compound is to fill the phosphorus compound into a container mainly made of PET and having a gateway, and then to introduce the container into the reaction system.

In other words, since phosphorus compounds generally corrode metal parts or turn into black foreign matter due to heat, the phosphorus compound addition port may become corroded or blocked by IJ-based foreign matter. These problems can be completely avoided by adopting this method.

The timing of adding the phosphorus compound, cobalt compound, and antimony compound of the present invention is after the completion of the esterification reaction (reaction rate: 90%).
(preferably 95% or more) is preferably present before the start of polycondensation.

The addition time of titanium dioxide is preferably approximately the same time as the addition time of the cobalt compound from the viewpoint of the color tone of the voluminous material. Titanium dioxide may be added as a mixture with a cobalt compound and an antimony compound, but in this case, it is preferable that the mixing time of the cobalt compound and titanium dioxide is 4 hours or less.

If the time is longer than 4 hours, the cobalt compound will aggregate the titanium dioxide, which is not preferable.

The amount of titanium dioxide added is 0 within the normally used range,
Preferably it is 0.01 to 2.5% by weight based on PET.

It is preferable to add EG in the form of a slurry.

Immediately after adding titanium dioxide, connect the addition line to EGO. 2
Washing with ~1% by weight of PET (preferably 0.5-3% by weight of PET) and disarmament as quickly as possible improves polymer whiteness, reduces DEG in the polymer, and improves titanium dispersibility. , more preferred.

0 In addition, polyester coloring inhibitors and other various additives used during the production of polyester can also be added within a range that does not impair the purpose of the present invention.

As described above, according to the present invention, it is possible to produce a polyester having good polymer whiteness, low DEG content, and good dispersion of titanium dioxide, but the most preferred method is as follows.

In other words, the BHT stored at a gauge pressure of 0.45k9/bulb or less
EG/TPA slurry (molar ratio 1.10 to 1.30) was supplied to the esterification reaction rate of 95% or more.'41,'5}
After adding phosphoric acid that satisfies the formula in a PET container, 4 to 10 minutes later, add slurry of cobalt acetate, antimony trioxide, and Ti02 that satisfies the formula t4}~{6i almost simultaneously from a separate port from the phosphoric acid addition port. This is a method in which 0.5% to 3% by weight of EG to PET is immediately added from the Ti02 addition line after drying, and the mixture is immediately superimposed under vacuum.

The present invention will be specifically explained below with reference to Examples.

In addition, in the examples, the color tone of the polymer was determined by using a color machine (
It is expressed as b value (Hunter value) measured by Suga Test Instruments Co., Ltd.). The dispersion of titanium dioxide in the chip was determined by adjusting a thin piece of the polymer with a microtome and then observing it under a microscope, using the following standard Z.

1st class (extremely good dispersibility) 2nd grade (with no agglomerated particles of titanium dioxide of 3 or more) (good dispersibility) Contains agglomerated particles of titanium dioxide of 3 to 5A Grade Z3 (
Slightly poor dispersibility) Those containing aggregated particles of titanium dioxide with 5 to 10 peaks Grade 4 (Poor dispersibility) Those containing aggregated particles of titanium dioxide with 10 or more peaks Grade 5 (Very poor dispersibility)
In addition, as a heat resistance evaluation method for polymers, %BrokenBond is determined from the value of intrinsic viscosity when the polymer is treated under nitrogen at 300°C for 8 hours. I gave it a rating of 2.

%BB=0.27[[ri]fin''3-[ri]finnExample 1 Reaction rate of 97.3% consisting of TPA and EG containing 8 pm of FBA 176 parts of BHT with a unit molar ratio of 1.20 (added) 122% by weight based on TPA) was added to the reactor.
TPA stored at 40qo and containing pm of FBA80 at normal pressure
144 parts and EG64.6 parts (EG to TPA molar ratio 1.2
0) was continuously provided at a constant speed for 3 hours and 45 minutes.
provided.

The temperature in the slurry supply house was controlled at 230 to 245°C to complete the reaction (reaction rate: 1°C), and 50% of this BHT was added.
was transferred to the next reaction tank and polycondensed as follows.

That is, 5 minutes after adding 0.015% by weight of phosphoric acid to PET (40.5ppm as phosphorus atoms) filled in a container having a gateway mainly made of PET (hereinafter referred to as a PET bottle), 0.035% of cobalt acetate was added. Weight% vs. PET
(082.7 ppm as cobalt atoms), 0.0 box wt% antimony trioxide vs. PET (250.3 ppm as antimony atoms), and 0.5 wt% titanium dioxide.
The EG slurry containing anti-PET was added from a phosphoric acid addition port and a separate port. Then immediately add EG20 from this addition line.
Immediately, the temperature was raised to 288°C for 6 minutes under a vacuum of 76°C to 1°C, and the temperature was raised to 288°C for 4 hours and 36 minutes until the intrinsic viscosity was 0.66. Condensed. As shown in Table 1 (Experiment No. 1), the polymer quality is b value -2. DECO in polymer. 94%, titanium dispersibility grade 01, %BrokenBond (300℃×
9Hr) of 0.99, which was a good quality, and the yarn reeling operability and yarn quality were also good. Example 2 After esterification in exactly the same manner as in Example 1, 50% of this BHT was transferred to the next reaction tank and disarmaed as follows.

That is, this BHn phosphoric acid (40% as a phosphorus atom)
Cobalt acetate (0.35 ppm as cobalt atoms) was added in a PET bottle after 5 minutes.
5-11 imitation pm vs. PET), antimony trioxide (125-375.5 ppm as antimony atoms vs. PET),
An EG slurry of 0.5% by weight titanium dioxide to PET was added through a separate port from the phosphoric acid addition port.

Immediately, EG20 was added from this addition line and immediately polycondensed to an intrinsic viscosity of 0.66 in the same manner as in Example 1. Polymers 2 to 11 were obtained. Example 1
The polymer quality of and 2 is shown in Table 1. Table 1 As is clear from Table 1, when Co was not added (No. 4 and 5), the polymer value was high, the amount of DEG in the polymer was large, and the titanium dispersibility was poor, and when the amount of Co added was large (No. 6,
7, p-0.5$o<-11), Co>0.091FB
A+30) indicates that the polymer has poor heat resistance.

Also, even if Co is added, P-0.5 > 25 (target.8,
It can be seen that in No. 9), the amount of DEG in the polymer was large and the dispersibility of titanium was also poor.

On the other hand, it can be seen that when the Sb amount is Sb<167 (No. 10), the polymerization time is long, and when Sb>3 is 1210 (No. 11), the heat resistance of the polymer is poor.

In contrast, No. 1, which is within the scope of the present invention. 1 (corresponding to Example 1) and M.1 (corresponding to Example 1). It can be seen that samples 2 and 3 are good in terms of polymer color tone, amount of DEG in the polymer, titanium dispersion, and heat resistance.

Example 3 Esterification was carried out in exactly the same manner as in Example 1, 50% of BHT was transferred to the next reaction tank, and 0.015% of phosphoric acid was added.
wt% to PET, 0.035 wt% cobalt acetate to PE
T, 0.0% by weight of antimony trioxide vs. PET, and 0.5% by weight of titanium dioxide vs. PET were added at different times, and then polycondensation was carried out in the same manner as in Example 1.

Table 2 shows the polymer color tone and titanium dispersibility. Except for adding slurry of cobalt acetate, antimony trioxide, and titanium dioxide within 2 to 1 powder after adding phosphoric acid (experimental vessel.2),
It can be seen that the polymer color tone becomes poor and the titanium dispersibility becomes poor.

Claims (1)

[Claims] 1. When producing a titanium dioxide-containing polyester from a dicarboxylic acid mainly consisting of terephthalic acid and a glycol mainly consisting of ethylene glycol, terephthalic acid is
- terephthalic acid containing 10 to 100 ppm of carboxybenzaldehyde, and after esterification (1),
A polyester characterized by adding a phosphorus compound satisfying the formula (2), and adding a cobalt compound and an antimony compound satisfying the formulas (1) to (3) within 2 to 15 minutes after the addition of the phosphorus compound. manufacturing method. -11≦P-0.53Co≦25...(1) 167≦S
b≦3.2P+210……(2)5≦Co≦0.09F
BA+30...(3) P, Co, and Sb are the amounts of added atoms [
ppm], ▲Mathematical formulas, chemical formulas, tables, etc.▼