JPS59126457A - Continuous production of modified polyester - Google Patents

Abstract

PURPOSE:To disperse a modifying agent uniformly in a base polyester preventing unnecessary thermal history, and to facilitate the washing of the apparatus in the exchange of the modifying agent, by mixing a base polyester with a polyester containing the modifying agent at the polymer delivery line of a continuous polymerization apparatus. CONSTITUTION:The base polyester obtained by the continuous polymerization is mixed with a polyester added or copolymerized with a modifying agent, at the delivery line of said base polyester. The base polyester is preferably a polyethylene terephthalate containing >=80mol% of ethylene terephthalate unit. It is efficient to add the modifying agent by branching a part of the base polyester from the delivery line, kneading the polyester with the modifying agent (content: 10-70wt%), returning the mixture to the delivery line, and mixing the composition with a static mixer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for continuously producing a modified polyester, and more specifically, a method for uniformly and continuously mixing a modifier into a base polyester obtained by continuous polymerization. The present invention relates to a method for producing modified polyester.

Polyester, especially polyester whose main repeating unit is ethylene terephthalate, has excellent moldability and physical properties, and is used as a fiber.

It is used in industrial applications such as films and molded products, but it has new properties that cannot be obtained from polyester alone, such as flame retardancy and antistatic properties, as long as the excellent performance inherent to polyester is not impaired.

It has properties such as easy dyeing and heat resistance. There is a strong demand for so-called modified polyesters, and many proposals have already been made. These polyester modification techniques can be roughly divided into the following three types.

(1) A method of introducing a third component having a modifying effect into polyester in some form.

(2) A method in which the external form of polyester alone is changed during molding.

(3) A method in which the above (1) and (2) are used in combination.

Typical methods for (1) include techniques such as copolymerization, addition, blending, and composites, while methods for (2) include techniques such as modifying the cross-sectional shape and hollowing out fibers. It will be done.

Needless to say, the purpose of the above-mentioned reforming technology is to diversify the final products, and many results have been achieved so far.

On the other hand, in recent years, the method of polymerizing polyester itself has been shifting from the conventional hatch polymerization method to a continuous polymerization method.

Compared to the batch polymerization method, the continuous polymerization method has less variation in the quality of the produced polymer, and is particularly advantageous in terms of rice production when producing large quantities of a particular brand over a long period of time. When producing high-mix, low-volume, brand-name polymers that meet specific needs, there is a drawback that it is difficult to make small adjustments. In particular, when producing modified polyester containing various modifiers as mentioned above, the entire huge continuous polymerization equipment must be cleaned every time the type of modifier is changed, which is very time consuming. There are a lot of losses.

In this way, in order to avoid the above-mentioned costs associated with continuous polymerization, the question of how to produce various modified polyesters that can meet the diversification of final needs is the question of how to produce polyesters in recent years. This is one of technology's biggest challenges.

In an attempt to solve such problems, a plurality of molten polymers at different two polymerization stages are taken out from the polymerization can as appropriate in a continuous polymerization apparatus composed of a multistage polymerization can, and blended or combined. By using the polymer alone, polyesters with 9 different degrees of polymerization can be obtained, or by appropriately combining these polyesters, it is possible to produce latent I shrinkable composite fibers efficiently and with a wide variety of combinations. The manufacturing technology is Special Publication No. 46-37767, Special Publication No. 47-8
No. 176, Special Publication No. 47-37647, Special Publication No. 48-2
No. 565 and Japanese Patent Application Laid-Open No. 54-36398.

However, in the method described above, it is possible to produce composite fibers having various combinations of polymerization degrees by adjusting the polymerization degree and mixing ratio of the polymers constituting the composite fibers when branched from multiple polymerization cans. Although there are advantages, there is a limit to diversification since it involves the combination of a plurality of polymers at different polymerization stages within the same continuous polymerization apparatus.

On the other hand, a method is known in which a mixing device is provided in a polymer discharging line from a continuous polyester polymerization device to add and mix various additives to polyester. However, in the past, additives were generally mixed directly into the molten polyester with a high degree of polymerization.

The dispersibility of additives was poor, making it unsatisfactory for use in fibers and films.

The present inventors have developed a technique for diversifying polyester produced by continuous polymerization, that is, how to uniformly apply various modifiers to heath polyester obtained by continuous polymerization.
As a result of intensive study on whether to mix them, the following findings were obtained and the present invention was achieved.

(If a modifier is directly added to 1,1 hese polyester, the dispersibility will be poor even if the mixing method described above is adopted, but it is modified to a polyester that is compatible with hese polyester.) By mixing a modifier-containing polyester to which a modifier has been added or copolymerized with a hese polyester, and dispersing and diluting the modifier, uniform dispersion suitable for use in fibers and films can be achieved.

(2) By mixing the modifier-containing polyester and the Heath polyester on the melting line where the Heath polyester is discharged from the continuous polymerization equipment, stable polymerization can be achieved with less deterioration of the polymer due to unnecessary heat debris. Modified polyester can be obtained continuously.

(3) Even when changing the modifier, it is sufficient to clean the mixing device, and there is no need to clean the huge continuous polymerization device, so it is easy to change the brand.

That is, 1 the present invention is a modification characterized in that a modifier-containing polyester to which a modifier has been added or copolymerized is mixed with the base polyester in a line for discharging the hemisphere polyester obtained by continuous polymerization. The gist of this paper is a continuous production method for polyester.

In the present invention, the base polyester refers to a polyester in a molten state discharged from a continuous polymerization apparatus, and preferably a polyethylene terephthalate polyester containing 80 mol% or more of ethylene terephthalate units is used.

The heath polyester itself is coated with some kind of strength modifier (for example, Ti01 as a dissipating agent or 5 as a hot water agent).
iOa, etc.) may be added, but as will be described later, it is preferable that such a modifier is not added. In particular, the addition of pigments, antistatic agents, flame retardants, and other modifiers to the base material should be avoided as much as possible.

This is the real deal! In JH Co., the modifier-containing polyester refers to the base polyester itself, or polyester polymerized in a polymerization device different from that of the base polyester, with TiO2 and 5iO1 as described above, and polyesters to which various conventionally known modifiers are added. It is a general term for polyesters copolymerized with a third component having a modifying effect, but it is particularly preferable to add and mix a modifier to the base polyester itself. This is because, in this case, a portion of the base polyester is removed from the discharge line of a continuous polymerization device, and a modifier-containing polyester is continuously produced by adding and mixing the modifier using a mixing device. This is because by returning the polyester to the dispensing line, it can be continuously and efficiently mixed with the remaining base polyester.

In the present invention, the polyester containing a modifier has already been explained, but when the polyester is obtained by adding and mixing a modifier to a base polyester branched from a discharge line of a continuous polymerization device, conventionally known mixing methods can be used. equipment can be used, but the modifier is TiO2 or 5
In the case of powder or granular material such as ift, an external stirring type mixing device is preferable because it facilitates uniform dispersion.

In the present invention, the mixing ratio of the modifier at the time of preparing the modifier-containing polyester can be appropriately selected depending on the content in the finally obtained modified polyester. In this case, in order to increase the mixing effect as much as possible, it is better to adopt a combination that increases the shearing force during mixing as much as possible. For example, when obtaining a modified polyester with a Ti (h content of 1% by weight) in the final product, the latter is better when the modifier content is 10% or 50% when producing the modifier-containing polyester. This is advantageous because the melt viscosity increases when the modifier is mixed, and as a result, the shear force also increases.On the other hand, when mixing a modifier, the melt viscosity decreases as the modifier content increases. In this case, it is preferable to suppress the content of the modifier when producing the modifier-containing polyester.

As mentioned above, it is preferable that the melt viscosity is as high as possible when producing the modifier-containing polyester, but if it becomes too high, the pressure loss may become significantly large.

Alternatively, care must be taken not to interfere with the stirring power, etc. Furthermore, if the content of the modifier is too high, dispersion is good in the modifier-containing polyester, but extreme dilution is required when mixing with the base polyester, which may actually worsen the dispersion. be. In such a case, it is also effective to once dilute and mix the modifier gold-white polyester with the third polyester before mixing it with the base polyester on the delivery line. The third polyester may be a polyester obtained using a polymerization apparatus different from that of the base polyester, or a
Any of the branches further removed from the polyester payout line may be used.

When the above is comprehensively judged, the content of the modifier in the modifier-containing polyester when mixed with the heisbory ester is particularly preferably in the range of 10 to 70% by weight.

In the present invention, it is necessary to mix the modifier-containing polyester and base polyester at the base polyester discharge line. The discharge line here means a place where the base polyester discharged from the continuous polymerization can is in a molten state. The reason for this has already been mentioned, but if the mixing is not performed on the base polyester discharging line (for example, the base polyester and the modifier-containing polyester are once made into chips, then melt-mixed again using an extruder, etc.). ), the manufacturing efficiency is poor and this is not preferable.

In the present invention, a conventionally known mixing device can also be used to mix the base polyester and the modifier-containing polyester, but in this case, both polyesters are in a molten state, and the modifier is not present in the modifier-containing polyester. Since they are already uniformly dispersed, relatively smooth mixing is possible even without a particularly large shearing force. Furthermore, in consideration of the energy required for mixing, it is advantageous to mix using a so-called static mixer. As the static mixing device, conventionally known devices such as a static mixer manufactured by Kenisox, a static mixing element manufactured by Sluzer, etc. can be suitably used.

Next, the configuration of the present invention will be specifically explained with reference to the drawings.

1 to 5 are flow diagrams showing embodiments of the present invention. In FIG. 1, the base polyester discharged from the final polymerization can 1 of the continuous polymerization device is transferred to a discharge line 2 containing a modifier 3, which is obtained by adding and mixing a modifier 3 to a separately polymerized polyester 4 via a mixing device 5. An example of mixing with polyester in the mixing device 6 is shown. FIG. 2 shows the case of a base polyester obtained by cutting off the polyester 4-gauge dispensing line 2 in FIG. FIG. 3 shows that when the modifier content is too high in FIG. 2, the modifier-containing polyester is added to a third polyester (in this example, further This shows the case of diluting and mixing with (branched base polyester).

1. Although not shown in the figure, 9. The modified polyester obtained by the present invention can be once made into chips and subjected to subsequent processes, or all or part of it can be directly spun, film-formed, etc. without being made into chips. It is also possible to subject it to a molding process.

The method of the present invention can be used not only when all the polyester obtained by continuous polymerization is made into a modified polyester, but also when a part of it is modified. This is particularly effective when the production capacity of the continuous polymerization apparatus is large and the amount of modified polyester produced is relatively small. For example, Fig. 4 shows the base polyester dispensed from the final polymerization can 1 of the continuous polymerization device in large quantities (three baselines 2-(11, 2
−(21 and 1−(31), 2−(1) and 2−
(2) is an example in which the line was directly subjected to spinning and chipping without adding a modifier, and the line was used to produce modified polyester using the method described above for the remaining 2-(31).

Furthermore, Fig. 5 shows an example in which the modified polyester production line in Fig. 4 is further divided into two lines 2-(31, 2-(4)) to simultaneously produce two types of modified polyester. .

The effects of the present invention will be explained below by giving examples.

Example 1 Using terephthalic acid and ethylene glycol as raw materials, polyethylene terephthalate containing no modifier obtained through an esterification reaction and a predetermined pre-polycondensation was continuously heated in a final polymerization vessel until its intrinsic viscosity reached 0.68. Polymerize, 100
It was supplied to a dispensing line as shown in FIG. 2 at a flow rate of 0 kg/H. On the other hand, using a two-shaft crosstalk device, 10 kg/
Ti1 was obtained by dispersing and mixing TiO2 supplied at a feed rate of H into polyethylene terephthalate which had been branched by 10 kg/H from the polyethylene terephthalate.
A polyethylene terephthalate containing a modifier having a t content of 50% by weight was prepared, and then this and the remaining 990 kg/
H polyethylene telescrate was mixed using a static mixing element SMX type (number of elements 18) manufactured by Sluzer Co., Ltd., and a portion (500 kg/H) was made into a deep layer, and the remaining (610 kg/H) was directly subjected to spinning. .

Ti01 in the chipped chips and TiO2 in the spun yarn
The degree of dispersion was measured and evaluated in the following manner.

That is, 7 to 14 mg of polymer was melted on a glass slide, sand-winched between two cover glasses, and 10 to 14 mg was melted using a microscope.
By measuring the number of Ti (h particles) larger than μ,
The degree of dispersion of Tjol was evaluated. The evaluation criteria were as follows.

Parac: 1 particle with a size of 10 μ or more / 6 mg or less B rank: 2 to 5 particles / 6 mg C rank =
6 to 10 pieces/6mg D rank: 11 pieces/6mg or more Based on conventional experience, A and B ranks are acceptable.

Examples 2 to 8 Modified polyesters were produced in which the amount of Ti01 added and the amount of polyethylene terephthalate branched from the hese line were varied in Example 1, and as in Example 1, a portion of it (500 kg/H ) was subjected to chi-rubbing, and the rest was directly subjected to spinning.

Table 1 lists the mixing conditions and results together with 7 Example 1.

Table 1 *0 indicates the number of particles of 10μ or more (pieces/6mg).

* * Punk pressure increase rate when spinning continuously for 2020 days under standard filtration conditions at a discharge rate of 35 g/min/spindle.

As can be seen from Table 1, when the content of Tr02 in the final polymer is constant, there is a tendency that the larger the amount of TiCh when mixing Ti0z and the branched polymer, the better the TiO2 dispersibility. In addition, the rate of increase in puncture pressure is correspondingly small. This is because, as already mentioned, when Ti01 and the branched polymer are mixed, the larger the ratio of TiO2, the higher the melt viscosity of the mixture, and the greater the shearing force.

Example 9 Using terephthalic acid and ethylene glycol as raw materials, polyethylene terephthalate containing no modifier obtained through an esterification reaction and a predetermined pre-polycondensation was continuously heated in a final polymerization reactor until its intrinsic viscosity reached 0.68. Polymerized to 100
It was supplied to the dispensing line shown in FIG. 1 at a flow rate of 0 kg/H. On the other hand, 1-50 kg/h of polyethylene terephthalate, which also does not contain a modifier, was polymerized by another method until the intrinsic viscosity reached 0.68, and 1-50 kg/h of polyethylene terephthalate, which also does not contain a modifier, was mixed with
TiO2-containing polyethylene terephthalate obtained by mixing with TiOx at 0 kg/J (and the above 100
The entire amount of modified polyester (1060 kg/H) obtained by mixing 0 kg/J4 of polyethylene terephthalate using a Scutisok mixer manufactured by Kenisoku Co., Ltd. was made into chips.

When the degree of dispersion of TiO2 in the chipped chip was evaluated in the same manner as in Example 1, the number of Ties particles of 10 μm or more was 3/6 mg.

Furthermore, when the chips were remelted and spun under the same discharge conditions as in Example 1, the spinning condition was good, and the rate of increase in pack pressure during continuous spinning for 20 days was 10%, so there were no particular problems. .

Example 10 Using terephthalic acid and ethylene glycol as raw materials, polyethylene terephthalate containing no modifier obtained through esterification reaction and predetermined pre-polycondensation was continuously heated in a final polymerization vessel until its intrinsic viscosity reached 0.68. Polymerized to 10
It was supplied to a dispensing line as shown in FIG. 3 at a flow rate of 00 kg/H. On the other hand, using the twin-screw kneading apparatus used in Example 1, TiO2 was mixed into 10 kg/h from the polyethylene terephthalate in the first stage at a feed rate of 10 kg/H.
It was premixed with polyethylene terephthalate which had been branched by kg/H, and then dispersed and mixed with 30 kg/H of branched polyethylene terephthalate, and then the Ti
O2-containing polyethylene terephthalate 50 kg/H
and 960 kg/11 polyethylene terephthalate were mixed again in the same static mixer as in Example 1. A part (500 kg/H) of the modified polyester was made into chips, and the remaining 5
10 kg/H was subjected to direct spinning under the same conditions as in Example 1.

The degree of dispersion of TiO2 in the chip is A rank.

Furthermore, there were no problems with the spinning condition or the rate of increase in bank pressure.

Example 11 In Example 1, carphone blank was used as a modifier instead of TiO2 at a feed rate of 20 kg/H,
Further, a black spun-dyed polyester was produced in the same manner as in Example 1 except that the amount of pruning of the base polyester was increased to 30 kg/h. The degree of carbon dispersion in the directly spun yarn was evaluated according to the above measurement method for TiO2, and it was found that carbon particles of 5μ or more were 31 [1i
It was 1/6 mg.

Further, the spinning condition was good, and the bank pressure increase rate was 10%, so there were no particular problems.

Example 12 The base polyester obtained at the same flow rate of <1000 kg/H as in Example 1 was distributed as shown in FIG. 4, and 150 kg/+1 of it was used for producing modified polyester. As a modifier, 4% of isophthalic acid is used for all acid components.
Separately prepared polyethylene terephthalate/isophthalate copolyester chips copolymerized with 0 mol%,
The 150 kg/H base polyester was mixed with 50 kg/H of the base polyester at a flow rate of 0 kg/H, and then mixed again with the remaining base polyester 100 kg/H using a static mixing device, and directly subjected to spinning. The obtained yarn was pre-knitted and dyed, and the uniformity of the dyeing property was examined. It showed good uniformity, indicating that the copolymerized polyester used as a modifier was uniformly dispersed and mixed in the modified polyester. I found out that there was.

[Brief explanation of drawings]

1-5 are flow diagrams showing embodiments of the present invention. 1--Final polymerization can of one continuous polymerization device, 2. 2-
111゜2-(21,2131,2-+41----Base polyester dispensing line, 3--Modifier, 4-Polyester, 5. 6--Mixing device. Patent applicant Nippon Ester Co., Ltd. agent People Yuzo Kodama 1m 2- (3)

Claims (1)

[Claims] +11 Modification characterized by mixing a modifier-containing polyester to which a modifier has been added or copolymerized with the base polyester in a discharging line of the base polyester obtained by continuous polymerization. Continuous production method for polyester. (2) Continuous production of the modified polyester according to claim 1, which is obtained by kneading a modifier with a modifier-containing polyester or a base polyester branched from a payout line of the base polyester. Law. (3) The method for continuously producing a modified polyester according to claim 1 or 2, wherein the base polyester is polyethylene terephthalate containing no modifier. (4) The modifier content of the modifier-containing polyester is 10~
70% by weight of the modified polyester according to claim 1, 2 or 3. (5) Claim 1, in which a static mixing device is used to mix the modifier-containing polyester and the base polyester;
The method for continuous production of modified polyester according to item 2, 3, 4, or 5.