JPH06220173A - Production of polyester - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a method for producing a molded article excellent in transparency, mechanical strength and hue, particularly a polyester useful for molding a container at a higher molding speed. [Structure] The main ester unit is ethylene terephthalate and the diethylene glycol component is 0.9-2.
In producing a polyester copolymerized with 2% by weight, an organotitanium compound obtained by treating titanium tetraalkoxide with an organic carboxylic acid as a catalyst for a transesterification reaction is used as titanium metal in an amount of 1 to 10 mmol% (based on the total acid component of the polyester). ), After the transesterification reaction is substantially completed, the orthophosphoric acid is 3 to 40 mmol% (based on the total acid component of the polyester) and the orthophosphoric acid / organotitanium compound molar ratio is 2 to 10. Add an amount of 0.05% of anthraquinone compound before the initial stage of polycondensation reaction.
~ 0.8 ppm (relative to the weight of polyester) added,
Then, using crystalline germanium dioxide treated with water colloid as a polycondensation reaction catalyst, the intrinsic viscosity is 0.7 to 0.8.
A method for producing a polyester, which comprises performing a polycondensation reaction until

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyester, and more particularly, to a molded article excellent in transparency, mechanical strength and hue, particularly a polyester useful for molding a container at a higher molding speed. It relates to a manufacturing method.

[0002]

2. Description of the Related Art Polyethylene terephthalate is widely used for fibers, films, industrial resins and the like because of its excellent mechanical properties and chemical properties, but recently it is also used for bottles, cups, trays and the like. ing. In particular, polyester bottles have come to be widely used as containers for foods, cosmetics, etc. due to their light weight and ease of handling.

As demand for bottles has increased in recent years and the fields of use thereof have become more diverse, many innovations have been made such as improving the molding speed and increasing the wall thickness of preforms depending on the fields of use. It's starting to happen. However, in the case of polyester resins that have been conventionally used for bottle molding, crystallization of bottles and preforms progresses, which causes whitening and impairs the appearance. On the other hand, if the molding speed is increased,
This will increase the shearing and heat generation of the resin during plasticization of the polyester, and the decrease in the molecular weight of the polyester due to thermal decomposition and the deterioration of the hue (yellowing) will also become noticeable, and the mechanical strength of the molded product will decrease and the molded product will become colored. There are also drawbacks such as deterioration of the appearance due to.

For these reasons, transparency, mechanical strength,
Development of a polyester capable of molding a molded product having an excellent hue is desired.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve such a problem, suppress whitening due to crystallization of a molded product, which tends to occur during high-speed molding or when molding a molded product having a large wall thickness, and improve transparency. Another object of the present invention is to provide a method for producing a polyester capable of producing a molded article which is excellent, and further has excellent mechanical strength and hue.

[0006]

The object of the present invention is to:
According to the invention, the main ester unit is ethylene terephthalate and the diethylene glycol component is 0.9
In the production of a polyester copolymerized with about 2.2% by weight, an organotitanium compound obtained by treating titanium tetraalkoxide with an organic carboxylic acid as a catalyst for a transesterification reaction is used as titanium metal in an amount of 1 to 10 mmol% (total acid of polyester). 3 to 40 mmol% of orthophosphoric acid after the transesterification reaction is substantially completed.
(To all the acid components of the polyester) and an orthophosphoric acid / organotitanium compound molar ratio of 2 to 10 is added, and the anthraquinone compound is added in an amount of 0.05 to 0.8 ppm before the initial stage of the polycondensation reaction. (Relative to the weight of polyester)
An intrinsic viscosity of 0.7 was obtained by using crystalline germanium dioxide added and hydrolyzed as a polycondensation reaction catalyst.
It is achieved by a method for producing a polyester, which is characterized by carrying out a polycondensation reaction until it becomes 0.8.

In the present invention, the polyester is a polyester in which the main ester unit is ethylene terephthalate and 0.9 to 2.2% by weight of a diethylene glycol component is copolymerized. Here, the "main" means a ratio of 85 mol% or more of all ester units (all repeating units). Therefore, in the range of 15 mol% or less of all the ester units, the diethylene glycol component is 0.9% or less.
.About.2.2% by weight, and other copolymerization components may be copolymerized.

Examples of such other copolymerization components include dicarboxylic acids other than terephthalic acid, oxycarboxylic acids, ethylene glycol and diols other than diethylene glycol. Specifically, aromatic dicarboxylic acids such as isophthalic acid, naphthalene dicarboxylic acid, biphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, diphenyl ketone dicarboxylic acid, sodium-sulfoisophthalic acid, dibromoterephthalic acid; alicyclic Dicarboxylic acids such as decalin dicarboxylic acid, hexahydroterephthalic acid and the like; aliphatic dicarboxylic acids such as malonic acid, succinic acid, adipic acid and the like; aliphatic diols such as trimethylene glycol,
Aromatic diols such as tetramethylene glycol, hexamethylene glycol, etc., such as hydroquinone, catechol, naphthalene diol, resorcin, 4,4′-dihydroxy-diphenyl-sulfone, bisphenol A
[2,2-bis (4-hydroxyphenyl) propane], tetrabromobisphenol A, bishydroxyethoxybisphenol A, etc .; alicyclic diol, such as cyclohexanediol; aliphatic oxycarboxylic acid, such as glycolic acid, hydroacrylic acid 3-oxypropionic acid, etc .; alicyclic oxycarboxylic acid, such as asiatic acid, quinobaic acid, etc .; aromatic oxycarboxylic acid, such as salicylic acid, m-oxybenzoic acid, p-oxybenzoic acid, mandelic acid, atrolactic acid And the like.

Furthermore, within the range where the polyester is substantially linear, a polyfunctional compound having a valence of 3 or more, such as glycerin,
Trimethylolpropane, pentaerythritol, trimellitic acid, trimesic acid, pyromellitic acid, tricarballylic acid, gallic acid, etc. may be copolymerized, and if necessary, monofunctional compounds such as o-benzoylbenzoic acid and naphthoic acid can be used. May be combined.

In the present invention, basically, the method accumulated in the production of polyethylene terephthalate can be carried out, and, for example, an ester-forming derivative of terephthalic acid (for example, a lower alkyl ester), ethylene glycol, and, if desired, co-production can be used. This can be carried out by a method of subjecting a polymerization component to a transesterification reaction and then subjecting a reaction product to a polycondensation reaction to obtain a polyester having a desired intrinsic viscosity. The transesterification reaction is preferably performed at a temperature of 170 to 235 ° C., and the polycondensation reaction is preferably performed at a high vacuum of several mmHg or higher and at a temperature of the melting point or higher and 280 ° C. or lower. It is not preferable in terms of hue.

The copolymerization ratio of the diethylene glycol component is such that diethylene glycol is added at any time during the reaction, and diethylene glycol is by-produced during the reaction (for example, the reaction time under normal pressure at high temperature is adjusted). The former is more preferable from the viewpoint of the hue of the polymer.

In the present invention, the transesterification reaction is carried out using an organotitanium compound obtained by treating titanium tetraalkoxide with an organic carboxylic acid as a catalyst.
Examples of the titanium tetraalkoxide include tetra-n-propoxy titanium, tetraisopropoxy titanium, tetra-n-butoxy titanium, tetraisobutoxy titanium, tetra-t-butoxy titanium, tetra-second-butoxy titanium and tetra-n. -Amyloxytitanium,
Triisoamyloxyisopropoxy titanium etc. are mentioned.

Preferred examples of the organic carboxylic acid include monocarboxylic acids such as acetic acid, propionic acid, n-butyric acid, caprylic acid and phenylacetic acid, and adipic acid, terephthalic acid, trimellitic acid, pyromellitic acid and the like. It may be a polyfunctional carboxylic acid.

The organotitanium compound obtained as a reaction product of these titanium tetraalkoxides and organic carboxylic acid is presumed to be an acyl compound derived from the corresponding carboxylic acid.

The amount of the organic titanium compound is 1 to 10 mmol% (based on the total acid component of polyester) in terms of titanium metal. If this amount is less than 1 mmol%,
The catalyst effect is small and the polymer productivity is lowered. On the other hand, when it exceeds 10 mmol%, the molecular strength at the time of molding is lowered and the mechanical strength is lowered, which is not preferable. Further, when the organotitanium compound is produced by a method that does not satisfy the range of the treatment method of the present invention, the effect as a catalyst is weak, the polymer productivity is lowered, and on the contrary, the effect as a catalyst is too strong to promote decomposition. However, it is not preferable because it lowers the mechanical strength of the molded product.

In the present invention, further, orthophosphoric acid is added after the transesterification reaction is substantially completed. The amount of orthophosphoric acid is 3 to 40 mmol% (based on the total acid component of the polyester) and the orthophosphoric acid / organotitanium compound molar ratio is 2 to 10.

If this amount is less than 3 mmol% (based on the total acid component of the polyester), the effect of suppressing thermal decomposition during molding is not sufficient, the mechanical strength is lowered, and the effect of suppressing oriented crystallization is also exerted. If it exceeds 40 mmol% (relative to the total acid component of the polyester), the transparency of the molded product is not sufficient. Will fall, which is not preferable. If the molar ratio of orthophosphoric acid / organo-titanium compound is less than 2, the effect of improving transparency and mechanical strength is not sufficient, while if it exceeds 10, the mechanical strength is rather lowered due to a decrease in molecular weight during molding. Yes, it is not preferable.

In the present invention, the anthraquinone compound is further added before the initial stage of the polycondensation reaction. Preferably, it is added when the internal temperature is 260 ° C or lower. If the polycondensation reaction is added from the middle stage to the latter stage, not only the effect is small but also foreign matter may be generated, which is not preferable.

The amount of anthraquinone compound added is 0.0
5 to 0.8 ppm (relative to the weight of polyester). If this amount is less than 0.05 ppm (based on the weight of polyester), the hue improving effect is insufficient, while 0.8
If it exceeds ppm (relative to the weight of polyester), the appearance of the molded article is rather poor because the molded article is bluish, which is not preferable.

Examples of the anthraquinone compound include 1-hydroxy-4-phenylaminoanthraquinone-3-carboxylic acid amide, 1-methylamino-4- (2-hydroxyethyl) aminoanthraquinone and 1,4-bis (methylphenylamino). ) Compounds exhibiting a blue color such as anthraquinone-3-sulfonic acid can be exemplified. Of these, 1,4-bis (methylphenylamino) anthraquinone-3-sulfonic acid amide is particularly preferable.

In the present invention, when the transesterification reaction product is subjected to polycondensation reaction, hydrocolloid-treated crystalline germanium dioxide is used as a catalyst for the polycondensation reaction. The powder of mere crystalline germanium dioxide or the one used in the slurry state of ethylene glycol or the like cannot achieve the object of the present invention because the transparency of the polymer is poor.

Examples of the method for treating hydrocolloid include the following methods. Crystalline germanium dioxide is dispersed in a large amount of ion-exchanged water so that the concentration is about 0.1 to 1 wt%, and heat treatment is performed at a temperature near the boiling point of water, for example, at 80 to 100 ° C. for several hours, for example, 3 to 10 hours. To do. It is also possible to distill water during the heat treatment to adjust the concentration.

The hydrocolloidal germanium dioxide treated by this method has an infrared absorption spectrum of 515,551,
It has an absorption of 587,872,955 cm ^-1 , and retains the hexagonal crystalline state before treatment, and the hydrate (500,78
It is not in the state of 0 cm ^-1 ). Then, it exhibits the Tyndall phenomenon, which is a characteristic of hydrocolloid solutions.

The amount of the crystalline germanium dioxide treated with the water colloid is 20 to 4 relative to the total acid component of the polyester.
It is preferably 0 mmol%.

In the polycondensation reaction, the intrinsic viscosity of the polymer is 0.7.
The reaction is carried out until it reaches 0.8, and the reaction conditions may be the conditions accumulated in the art as described above. For example, it can be carried out by a melt polymerization method, or a prepolymer having a low degree of polymerization can be prepared by melt polycondensation, pelletized and then polycondensated to a predetermined degree by a solid phase polymerization method.

The intrinsic viscosity of the polymer after the polycondensation reaction is 0.
When it is less than 7, the mechanical strength of the molded product is not sufficient, while when it exceeds 0.8, the resin heat generation increases during the plasticization process of the polyester during molding, which not only causes a decrease in the mechanical strength, but also the oriented crystals. It is not preferable because it is promoted and the transparency is deteriorated.

As described above, the polyester of the present invention contains 0.9 to 2.2% by weight of the diethylene glycol component.
Although it is copolymerized, if this amount is less than 0.9% by weight, the resin heat generation during the plasticizing process of the polyester during molding increases the mechanical strength due to the decrease in the molecular weight and also causes the oriented crystallization. Is promoted and transparency is deteriorated,
On the other hand, when it exceeds 2.2% by weight, the hue is deteriorated, the thermal stability is lowered, and the mechanical strength is lowered due to the decrease in the amount during molding, which is not preferable.

As described above, the copolymerization ratio of diethylene glycol can be adjusted by adding diethylene glycol at any time during the reaction or by-producing diethylene glycol during the reaction. As a method for producing diethylene glycol as a by-product, (1) the holding time at high temperature and normal pressure is set longer than usual at the initial stage of polymerization. (2) After completion of the transesterification reaction, the state of adding orthophosphoric acid is maintained. (3) The polymerization catalyst is added before the end of the transesterification reaction. Etc. can be illustrated.

In the present invention, other additives such as colorants, antioxidants, ultraviolet absorbers, antistatic agents, flame retardants, acetaldehyde regeneration inhibitors and the like may be used, if necessary. For hygiene, it is better not to add anything as much as possible.

[0030]

EXAMPLES The present invention will be further described below with reference to examples. In addition, "part" in an Example means a weight part. Moreover, the measuring method of the characteristic used in the Example is shown below.

1) Intrinsic viscosity: [η] phenol / tetrachloroethane (weight ratio 60/40)
It was calculated from the solution viscosity measured at 35 ° C using the mixed solvent of.

2) Diethylene glycol (DEG) amount About 2 g of a sample is precisely weighed, 10 ml of hydrazine containing an internal standard is added thereto, and the mixture is heated at 100 ° C. for 30 minutes. The obtained decomposition liquid was centrifuged and the liquid layer sample was quantitatively analyzed by gas chromatography.

3) Hue (color b value: Colb) The hue b value was measured with a CM-1500 type color machine manufactured by Color Machine.

4) Bottle Haze The dry polymer was applied to the cylinder at a temperature of 295 ° C. and an injection pressure of 35.
% Preforms weighing 50 g are injection molded in a 33 second cycle. After cooling, it was reheated to 105 to 110 ° C. and subjected to biaxial stretching blow to obtain a bottle having an internal volume of 1 liter, and the preheating time at which the bottle could be blown without whitening was used as a measure of bottle haze. It means that the longer the preheatable time is, the less haze is generated and the better the transparency is. When the preheatable time was less than 90 seconds, the result was x, when it was 90 seconds or more and less than 110 seconds, it was evaluated as Δ, and when it was 110 seconds or more, it was evaluated as o.

5) Bottle Intrinsic Viscosity The body of the bottle molded by the above method was sampled and measured.

[0036]

Example 1 100 parts of ethylene glycol was heated with stirring, and when the temperature reached 60 ° C., 8 parts of titanium tetrabutoxide and 6 parts of acetic acid were added and mixed for 20 minutes. Then, the mixture was allowed to cool to obtain an ethylene glycol solution of titanium acetate. The concentration of titanium metal in this solution is 1.0% by weight.
Met.

Further, crystalline germanium dioxide is dispersed in a large amount of ion-exchanged water so as to have a concentration of about 0.1 to 1% by weight, heat-treated at 80 to 100 ° C. for 6 hours, and finally the concentration is adjusted to 0.8. The content was adjusted to be wt% to obtain crystalline germanium dioxide treated with hydrocolloid (hereinafter abbreviated as hydrocolloid Ge).

17,000 parts of dimethyl terephthalate, 11000 parts of ethylene glycol, an ethylene glycol solution of titanium acetate prepared above (1% as Ti) 12
Parts, 100 parts of diethylene glycol and 1,4-bis (methylphenylamino) as an anthraquinone compound
3 parts of anthraquinone-3-sulfonic acid amide was charged into a transesterification reaction tank, and transesterification was carried out at 170 to 235 ° C. When the distillate was stopped, 420 parts of the hydrocolloid Ge and 2 parts of a 55 wt% orthophosphoric acid aqueous solution were added.
Part of the mixture was added and transferred to a polymerization reaction tank. The reaction was carried out at 260 to 270 ° C. for about 30 minutes under normal pressure, and then at 265 ° C. under high vacuum (high vacuum of several mmHg or more) for about 2 hours. Then, it was extracted from a polymerization reaction tank into a large amount of running water by a conventional method to obtain a strand type chip. [Η] of this chip was 0.53.

This chip was pre-dried at 150 to 160 ° C. for about 3 hours and then dried at 225 ° C. under high vacuum of 0.5 mmHg for 1 hour.
Solid phase polymerization was carried out for 4 hours. [Η] of the chip after solid state polymerization
Was 0.76, and the amount of copolymerized diethylene glycol was 1.7 wt%. The Colb value of the chip was 0.3. After molding a bottle from this tip,
The [η] of the bottle was 0.71 and the haze of the bottle was good.

The results are shown in Table 1.

[0041]

Examples 2 and 3 Example 1 except that the amounts of additives (organo-titanium compound, phosphorus compound) added, the molar ratio, the polymer [η] and the amount of diethylene glycol (DEG) were changed as shown in Table 1. I went the same way.

The results are shown in Table 1.

[0043]

[Comparative Examples 1 to 4] The same procedure as in Example 1 was carried out except that the types and amounts of additives (organic titanium compound, phosphorus compound) were changed as shown in Table 1.

The results are shown in Table 1.

[0045]

[Table 1]

[0046]

Comparative Examples 5 to 6 Example 1 except that the addition amount of the anthraquinone compound 1,4-bis (methylphenylamino) anthraquinone-3-sulfonic acid was changed as shown in Table 2.
I went the same way.

The results are shown in Table 2. The results of Example 1 are also shown in Table 2.

[0048]

[Table 2]

[0049]

[Comparative Examples 7 to 8] "Slurry Ge" as polycondensation catalyst
(The crystalline germanium dioxide powder is directly dispersed in ethylene glycol to 20 wt% and subjected to a sand gliding process to obtain an ethylene glycol slurry of germanium dioxide. The representative particle size was 4 to 6 µ). Except that 8 parts or 3.4 parts of "Powder Ge" (indicating powdered crystalline germanium dioxide) are used.
The same procedure as in Example 1 was performed.

The results are shown in Table 3. The results of Example 1 are also shown in Table 3.

[0051]

[Table 3]

[0052]

Comparative Examples 9 to 12 The same procedure as in Example 1 was carried out except that the amounts of [η] and diethylene glycol of the polymer were changed.

The results are shown in Table 4. The results of Example 1 are also shown in Table 4.

[0054]

[Table 4]

[0055]

INDUSTRIAL APPLICABILITY The present invention suppresses whitening due to crystallization of a molded product, which is likely to occur during high-speed molding or molding of a thick molded product, and has excellent transparency, and further has excellent mechanical strength and hue. A polyester capable of producing an excellent molded product can be produced, which is extremely effective as a method for producing a molding polyester.

Claims (1)

[Claims] 1. A main ester unit is ethylene terephthalate, and a diethylene glycol component is 0.9 to 10.
In the production of a 2.2% by weight copolymerized polyester, an organic titanium compound obtained by treating titanium tetraalkoxide with an organic carboxylic acid as a catalyst for a transesterification reaction is used as titanium metal in an amount of 1 to 10 mmol% (total acid component of polyester). Orthophosphoric acid is used in an amount of 3 to 40 mmol% after the transesterification reaction is substantially completed.
(To all the acid components of the polyester) and an orthophosphoric acid / organotitanium compound molar ratio of 2 to 10 is added, and the anthraquinone compound is added in an amount of 0.05 to 0.8 ppm before the initial stage of the polycondensation reaction. (Relative to the weight of polyester)
An intrinsic viscosity of 0.7 was obtained by using crystalline germanium dioxide added and hydrolyzed as a polycondensation reaction catalyst.
A method for producing a polyester, which comprises carrying out a polycondensation reaction until it becomes 0.8.