JPH0480932B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical field] The present invention is an adipic acid copolymer with an excellent color tone and a high degree of polymerization, which is composed of a dicarboxylic acid component consisting of terephthalic acid or a derivative thereof, adipic acid or a derivative thereof, and 1,4-butanediol. The present invention relates to a method for producing polyester. [Prior art and its problems] Terephthalic acid copolyester is widely known as a material suitable for various uses such as films, fibers, molding resins, and adhesives. In such terephthalic acid-based copolymerized polyesters, many dicarboxylic acids are used as the dicarboxylic acid component copolymerized with terephthalic acid or its derivatives, but among them, adipic acid or its derivatives, which are polyamide raw materials, are available at low cost. is an easy raw material. On the other hand, titanium compounds are generally used as catalysts for the production of polyesters due to their excellent catalytic activity; however, when producing polyesters using adipic acid as a copolymerization component in the presence of titanium compounds, There is a problem that the resulting polymer is significantly colored. For example, in JP-A-57-90016, a polyester consisting of a dicarboxylic acid component whose acid components are terephthalic acid and adipic acid and a glycol component mainly composed of ethylene glycol or ethylene glycol is prepared in the presence of a glycol-soluble titanium compound. A method of manufacturing is disclosed. However, the polyester obtained by such a method is colored red, and the polyester is colored red.
It often becomes a serious hindrance in various applications such as fibers and molding resins. Such coloring is unavoidable even when 1,4-butanediol is used as the glycol component. That is, according to the studies of the present inventors, terephthalic acid, adipic acid and 1,4
- When a titanium compound is used as a catalyst for esterification or transesterification and then polycondensation using butanediol as a starting material, the resulting polymer becomes markedly red, and the polycondensation reaction itself It was found that polyester with a high degree of polymerization could not be obtained due to a significant delay in the process. In order to solve this problem, the present inventors conducted intensive studies on a method for producing adipic acid copolyester that prevents coloring of the polymer and has a high degree of polymerization, and as a result, they discovered the present invention. be. [Objective of the Invention] That is, the object of the present invention is to provide a method for stably industrially producing adipic acid copolymerized polyester having high whiteness and high degree of polymerization. An object of the present invention is to provide a method for producing an adipic acid copolyester that can be used in a wide range of applications such as industrial resins. These objects of the present invention can be achieved by the invention described in the claims above. The present invention will be explained in detail below. [Structure of the invention] The main starting materials used in the present invention are (A) terephthalic acid or its derivatives, (B) adipic acid or its derivatives, and (C) 1,4-butanediol. Examples of derivatives include lower alkyl esters of terephthalic acid, such as dimethyl terephthalate and diethyl terephthalate. Derivatives of adipic acid include lower alkyl esters of adipic acid, such as dimethyl adipate,
Examples include diethyl adipate. In addition, small amounts of other copolymerization components can be used as long as the characteristics of the copolymerized polyester of the present invention are not impaired, and such copolymerization components include isophthalic acid, p-oxybenzoic acid, 2,6-naphthalene dicarboxylic acid, 5-sodium sulfoisophthalic acid, hexahydroterephthalic acid, sebacic acid, succinic acid, pimelic acid, suberic acid, azelaic acid, malonic acid, etc., and their lower alkyl esters, ethylene glycol, propylene glycol, neopentyl glycol, cyclohexane di Examples include methanol, diethylene glycol, polytetramethylene glycol, hexamethylene glycol, and hexanediol. The reaction ratio of (A) terephthalic acid or its derivative and (B) adipic acid or its derivative is (A)/(B)
=95-40 mol%/5-60 mol% is preferably used. In the present invention, titanium compounds used as catalysts for esterification or transesterification reactions and polycondensation reactions include organic compounds such as tetra-n-butyl titanate, tetra-n-propyl titanate, tetraisopropyl titanate, tetraethyl titanate, and tetramethyl titanate. For polyester production such as titanate and its hydrolyzate, titanium tetrachloride, titanium sulfate hydrolyzate, inorganic titanium compounds such as titanium potassium fluoride, titanium zinc fluoride, titanium cobalt fluoride, titanium oxalate, titanium potassium oxalate, etc. Known titanium compounds can be used as catalysts, with tetra-n-butyl titanate and tetraisopropyl titanate being preferred. Two or more of these titanium compounds may be used in combination. In the esterification or transesterification reaction, the titanium compound is usually added at the raw material charging stage or at the beginning of the esterification or transesterification reaction. Further, the titanium compound as a polycondensation reaction catalyst may be added all at once in the previous step, but preferably it is further added in the polycondensation reaction step. The timing of additional addition to the polycondensation reaction process is as follows:
It is usually added between after the completion of the esterification or transesterification reaction and before the completion of the polycondensation reaction, and particularly preferably just before the start of the polycondensation reaction. The amount of the titanium compound added in the esterification or transesterification reaction varies depending on the reaction conditions, the type of titanium compound, etc., but usually the acid component of the starting material 1
It is in the range of 0.3×10 ⁻⁴ to 15×10 ⁻⁴ mol per mole. In addition, in the case of polycondensation reaction, the reaction conditions,
Although it varies depending on the type of titanium compound, it is usually 0.3×10 ^-4 to 15× per mole of the acid component of the starting material.
It is in the range of 10 ⁻⁴ mol. Furthermore, in the esterification, transesterification, and polycondensation reactions, the titanium compound described above and other known catalysts can be used in combination. Examples of such other catalysts include metals such as tin, zinc, germanium, antimony, and cobalt. Examples include compounds. The present invention provides esterification or transesterification of the starting material in the presence of a titanium compound,
The obtained reaction product is subjected to a polycondensation reaction in the presence of a titanium compound and a pentavalent phosphorus compound, and in particular, by using a titanium compound and a pentavalent phosphorus compound together as a catalyst during the polycondensation reaction,
This makes it possible to produce an adipic acid copolymerized polyester with excellent whiteness and a high degree of polymerization. The phosphorus compound of the present invention needs to be a pentavalent phosphorus compound; for example, even if a monovalent or trivalent phosphorus compound is used, the object of the present invention cannot be achieved. The role played by such a pentavalent phosphorus compound is not only to be extremely effective in preventing coloration, but also to have the effect of accelerating the polycondensation reaction. Examples of the pentavalent phosphorus compounds of the present invention include phosphoric acid, pyrophosphoric acid, metaphosphoric acid, trimethyl phosphate, tri-n-butyl phosphate, tricresyl phosphate, triphenyl phosphate, hexamethylphosphoramide, hexamethylphosphoramide, and hexamethylphosphoramide. Licotriamide, butyl acid phosphate, lauryl acid phosphate, 2-ethylhexyl acid phosphate, bis[(2-hydroxyethyl) methacrylate] acid phosphate, phenylphosphonic acid, diphenylphosphinic acid, phosphoric acid Boron, lithium phosphate, primary ammonium phosphate, secondary ammonium phosphate,
Examples include aluminum phosphate, preferably phosphoric acid, trimethyl phosphate, tri-n-butyl phosphate, triphenyl phosphate, hexamethylphosphoramide, boron phosphate, and the like. Two or more types of these phosphorus compounds may be used. The phosphorus compound is usually added between after the completion of the esterification or transesterification reaction and before the completion of the polycondensation reaction, but preferably just before the start of the polycondensation reaction. In addition, the amount of the phosphorus compound added is 4× for 1 mole of the adipic acid component used.
10 ⁻⁴ to 40×10 ⁻⁴ mol, preferably 5×10 ⁻⁴ to 20×
10 ^-4 mol is good. If the amount is less than 4×10 ⁻⁴ mol, the effect of preventing the adipic acid copolyester produced from being colored red will be insufficient, and the polymerization reactivity will also tend to deteriorate. On the other hand, if the amount exceeds 40×10 ⁻⁴ mol, a polymer with high whiteness can be obtained, but on the other hand, the polymerization reactivity tends to deteriorate, which is not preferable. In addition, when carrying out the polycondensation reaction, an antioxidant such as a hindered phenol compound, a matting agent such as titanium oxide, a modifier, etc. can also be used as necessary. [Effects of the Invention] According to the present invention, an adipic acid copolymerized polyester having excellent whiteness and a high degree of polymerization can be stably obtained without delaying the polycondensation reaction. In addition, it will greatly expand the applications of adipic acid copolyester, including the development of various applications such as films, fibers, and molding resins, and its usefulness is extremely large. Hereinafter, the present invention will be explained in more detail with reference to Examples. In addition, in the examples, the relative viscosity is 8g of polymer.
After dissolving in 100 ml of orthochlorophenol (dissolution conditions: 100°C, about 1 hour), it was allowed to cool and measured at 25°C using an Ostwald viscometer. Further, the color tone (L, a, b) of the polymer is a value measured using a pigment meter after the obtained polymer is once made into chips. L is the lightness (the larger the value, the brighter), a is the red-green hue (+ is reddish, - is greenish), b is the yellow-blue hue (+ is yellowish, - is bluish)
represents. Note that parts indicate parts by weight. Example 1 81 parts of terephthalic acid, 31 parts of adipic acid and 1,
After charging 113 parts of 4-butanediol into a reactor equipped with a rectification column and adding 0.08 part of tetra-n-butyl titanate, the temperature was gradually raised to carry out an esterification reaction. After an esterification time of 2 hours and 50 minutes, the reaction system became transparent and the esterification reaction was completed with 36 parts of esterification distillate. This reaction product was transferred to an autoclave, and first a solution of 0.03 parts of phosphoric acid and 5 parts of 1,4-butanediol was added.After 5 minutes, 0.12 parts of tetra-n-butyl titanate was added, and the temperature was gradually raised and the pressure reduced. Do 1
After an hour, a temperature of 247°C and a degree of vacuum of 0.2 mmHg were reached, and the polycondensation reaction was carried out for 3 hours and 25 minutes under these conditions. The obtained polytetramethylene terephthalate
The relative viscosity of the adipate copolymer was 40.8. In addition, the polymer color tone is L value: 80.5, A value: -0.2,
A polymer with b value: +5.8 and high whiteness was obtained. Comparative Example 1 Esterification and polycondensation reactions were carried out in the same manner as in Example 1 except that phosphoric acid was not added. A polytetramethylene terephthalate/adipate copolymer having a relative viscosity of 24.6 was obtained in a polycondensation reaction time of 5 hours. The color tone of this polymer is L value: 57.4, A value: +
25.1, b value: +16.7, and had an extremely strong red tinge. Example 2 95 parts of dimethyl terephthalate, 37 parts of dimethyl adipate, and 113 parts of 1,4-butanediol were charged into a reactor equipped with a rectifying column, and 0.06 part of tetraisopropyl titanate was added thereto, and the temperature was gradually raised to carry out a transesterification reaction. Summer. Transesterification reaction time 2
The transesterification reaction was completed in 30 minutes with 46 parts of esterification distillate. This reaction product was transferred to an autoclave, and first a solution of 0.10 parts of triphenyl phosphate and 5 parts of 1,4-butanediol was added. After 5 minutes, 0.10 parts of tetraisopropyl titanate was added, and the temperature was gradually raised and the pressure reduced. After one hour, the temperature reached 247°C and the degree of vacuum reached 0.2 mmHg, and the polycondensation reaction was carried out for 3 hours and 30 minutes. The obtained polytetramethylene terephthalate
The relative viscosity of the adipate copolymer was 41.6. In addition, the polymer color tone is L value: 82.2, A value: -0.4,
A polymer with b value: +5.6 and high whiteness was obtained. Examples 3 to 7, Comparative Examples 2 to 6 Esterification was carried out in the same manner as in Example 1, except that the type and amount of the phosphorus compound added during the polycondensation reaction were variously changed as shown in Table 1. Reactions and polycondensation reactions were carried out. The polycondensation reaction time, relative viscosity and color tone of the obtained polymer were
Shown in the table. It is understood that the phosphorus compounds of the present invention exhibit excellent effects.

【table】

[Table] Example 8 59 parts of terephthalic acid, 52 parts of adipic acid and 1,
109 parts of 4-butanediol was charged into a reactor equipped with a rectification column, and 0.08 part of tetra-n-butyl titanate was added to carry out an esterification reaction. This reaction product was transferred to an autoclave, and a mixture of 0.075 parts of boron phosphate and 5 parts of 1,4-butanediol was added so that the number of moles per 1 mole of adipic acid was 20 x 10 ^-4 , and then tetra n
-0.12 parts of butyl titanate was added to carry out a polycondensation reaction. The polycondensation reactivity was good, and the color tone of the obtained polytetramethylene terephthalate/adipate copolymer was as follows: L value: 81.6, a value: -0.3, b value:
It had a high whiteness value of +5.8.

Claims (1)

[Claims] 1. Terephthalic acid or its derivatives, adipic acid or its derivatives, and 1,4-butanediol are esterified or transesterified in the presence of a titanium compound, and the resulting reaction product is esterified or transesterified with a titanium compound and 1,4-butanediol. A method for producing a highly white and highly polymerized adipic acid copolyester, which comprises carrying out a polycondensation reaction in the presence of a pentavalent phosphorus compound. 2 The amount of titanium compound present in esterification or transesterification reaction per mole of acid component
The amount ranges from 0.3×10 ^-4 to 15×10 ^-4 mol, and the amount of titanium compound present in the polycondensation reaction is 1% of the acid component.
0.3×10 ^-4 to 15×10 ^-4 mol and 5
The highly white and highly polymerized adipine according to claim 1, wherein the amount of the phosphorus compound present is in the range of 4 x 10 ^-4 to 40 x 10 ^-4 mol per 1 mol of the adipic acid component. A method for producing acid copolymerized polyester. 3. High whiteness, high polymerization degree adipic acid copolymerized polyester according to claim 1, wherein the copolymerized amount of adipic acid or its derivative is 5 to 60 mol% relative to 95 to 40 mol% of terephthalic acid or its derivative. manufacturing method.