JPH0585569B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing flame-resistant polyester. (Prior art) Due to its excellent mechanical and chemical properties, polyester is widely used as textiles for clothing and industrial purposes, as well as films for magnetic tapes, photographs, capacitors, etc., and for molding bottles, etc. Widely used for things. Incidentally, in recent years, there has been an increasing demand for synthetic fibers and various plastic products to be flame resistant from the viewpoint of fire prevention. Conventionally, various attempts have been made to impart flame resistance to polyester, and it has been said that it is effective to incorporate phosphorus compounds into polyester. Phosphite esters, phosphate esters, and phosphonate esters etc. have been proposed. However, when a phosphorus compound is added to polyester, generally (1) gelation of the polyester occurs, (2) addition of the phosphorus compound lowers the melting point and glass transition point of the polyester, and (3) residual rate of the phosphorus compound. (4) The color tone of the polyester deteriorates.
(5) There was a problem that toxic gas was likely to be generated during each process such as spinning, stretching, and molding. Japanese Patent Publication No. 55-41610 proposes a flame-resistant polyester copolymerized with a specific phosphinic acid compound, which largely solves the above problems, but this phosphorus compound is expensive, and polyester There is a problem in that adding a sufficient amount to impart sufficient flame resistance to polyester increases the cost of polyester production. (Problems to be Solved by the Invention) The present invention provides a method for producing polyester that can be produced at low cost, exhibits excellent flame resistance, has a high glass transition point, and has good color tone, moldability, physical properties, etc. This is what we are trying to provide. (Means for Solving the Problems) The present invention achieves the above object and has the following configuration. When producing polyester from a dicarboxylic acid component, a diol component, and/or an oxycarboxylic acid component, a phosphorus compound represented by the following general formula [I] is added to a polyester with a phosphorus atom content of 500 ppm.
A method for producing flame-resistant polyester, characterized by adding the above.

[Chemical formula] In formula [I], R ¹ is an ethylene group or 1,
2-phenylene group (which may have a substituent), A
represents a divalent or trivalent organic group, R ² represents a monovalent ester-forming functional group, and m and n are 1 or 2. As the main components forming the polyester of the present invention, terephthalic acid as a dicarboxylic acid component, ethylene glycol as a diol component, and 4-oxybenzoic acid (all including ester-forming derivatives) as an oxyacid component are preferably used. ,
Isophthalic acid, 5-sodium sulfoisophthalic acid, adipic acid, trimellitic acid, diethylene glycol, propylene glycol, 1,4-cyclohexanedimethanol, 1,4-butanediol, pentaerythritol, etc. may be used in combination as copolymerization components. A in phosphorus compound [I] is divalent (n=1)
or a trivalent (n=2) organic group, and specific examples include the following. Alkyl groups such as methylene group, ethylene group, isopropylidene group, cyclohexylene group, arylene group such as alkylidene group, p-phenylene group, m-phenylene group, 1,4-naphthalene group, 2,6-naphthalene group, 1 , 2,3-propanetriyl group, etc., a trivalent cyclohexane ring group, a trivalent benzene ring group, or a trivalent naphthalene ring group. Moreover, as R ² in the phosphorus compound [I],
Examples include hydroxyl groups, carboxyl groups, and ester-forming derivatives thereof. The 1,2-phenylene group of R ¹ may have a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, a halogenated hydrocarbon group, or the like as a substituent. Specific examples of -A-(R ² ) _o include the following groups, those obtained by converting these carboxyl groups into lower alkyl ester groups such as methyl and ethyl, or acid anhydride groups, and those in which the hydroxyl group is converted to an acetyl ester group or an acid anhydride group. Examples include those converted to hydroxyethoxy groups.

【formula】

【formula】

【formula】

【formula】

[Formula] Specific examples of the phosphorus compound [I] include the following compounds and ester-forming derivatives thereof.

【formula】

【formula】

【formula】

【formula】

【formula】

[ka]

[ka]

【formula】

[ka]

[ka]

[ka]

[ka]

[ka]

[ka]

[Chemical] In addition, among the above-mentioned phosphorus compounds, those having a phenolic hydroxyl group have a weak ester-forming ability when left unformed, so they are converted into an ester-forming derivative such as acetyl ester and subjected to the reaction. This is desirable. Phosphorus compound [I] is produced by heating a compound represented by the following formula [] (referred to as phosphinic acid) and a quinone such as p-benzoquinone or 1,4-naphthoquinone in a solvent such as ethyl cellosolve, and as necessary. to convert the hydroxyl group of the reaction product into other ester-forming functional groups, or itaconic acid, dimethyl itaconate, 2-butene-1,4-diol, 2-butene-1,4-diol diacetate. It can be obtained by addition reacting a compound having a double bond and an ester-forming functional group with phosphinic acid.

[Chemical] To convert the hydroxyl group of the reactant of phosphinic acid and quinones into other ester-forming functional groups,
For example, this reactant may be heated to react with a carboxylic acid anhydride such as acetic anhydride, or an alkali metal salt of this reactant may be reacted with alkylene carbonate, alkylene oxide, polyalkylene oxide, mono- or diglycidyl ether thereof, or epihalohydrin. can be converted into other ester-forming functional groups by reacting with . The above-mentioned phosphorus compounds may be used as they are in the synthesis of copolymerized polyesters, but they may also be used in the form of monomers, oligomers, or polymers reacted with acid components such as frephthalic acid and isophthalic acid. The amount of the phosphorus compound added is 500 ppm or more, preferably 1000 to 1000 ppm as phosphorus atoms based on the polyester.
The content must be 10,000ppm.
(Determine the amount added by taking into account that some of the phosphorus compound will scatter during polycondensation.)
If it is less than 500 ppm, the flame resistance will be insufficient, and if it is too much, gelation will occur before the degree of polymerization required to maintain the strength properties required for polyester is reached, and the good physical properties inherent to polyester will be impaired. Problems may arise in terms of operation and physical properties of polyester. The phosphorus compound may be added when producing polyester by a conventional method. That is, when producing polyester from dicarboxylic acid or dicarboxylic acid diester and diol by esterification or transesterification reaction and polycondensation reaction, it is added at any stage from the esterification or transesterification reaction to the desired stage of the polycondensation reaction. can do. Note that depending on the type of phosphorus compound and the timing of addition, it may not be possible to obtain a polyester with a high degree of polymerization. For example, when using a phosphorus compound with one ester-forming functional group, it may act as a terminal capping agent. In such cases, pentaerythritol, trimellitic acid, trimesic acid,
Consideration must be given to the combined use of polyfunctional compounds such as pyromellitic acid. The polycondensation reaction when producing polyester is usually carried out at 260 to 310°C under reduced pressure of about 0.01 to 10 mmHg.
It is preferably carried out at 275 to 290°C until a predetermined degree of polymerization is obtained. Moreover, the polycondensation reaction is carried out in the presence of a catalyst,
Conventionally used catalysts include antimony, titanium, germanium, tin, zinc, aluminum, magnesium, calcium, manganese,
In addition to metal compounds such as cobalt, organic sulfonic acid compounds such as sulfosalicylic acid and o-sulfobenzoic anhydride are preferably used. The amount of catalyst added is based on 1 mole of the acid component constituting the polyester.
1×10 ⁻⁵ to 1×10 ⁻² mol, preferably 5×10 ⁻⁵ to
A suitable amount is 5 x 10 ^-3 mol, most preferably 1 x 10 ^-4 to 3 x 10 ^-3 mol. In addition, in the present invention, stabilizers such as hindered phenol compounds, cobalt compounds, fluorescent agents,
Additives such as color improvers such as dyes and pigments such as titanium dioxide may be included. The polyester of the present invention can be used in the production of products such as fibers, films, and bottles depending on its properties, and those containing a large amount of phosphorus compounds can be used as flame retardants for polyester. (Function) Although the reason why the polyester of the present invention exhibits excellent flame resistance is not clear, the phosphorus compound promotes thermal decomposition and dehydration of the polyester when it comes into contact with flame, promoting melting and falling, resulting in good flame resistance. It is recognized that When flame resistance is imparted by a phosphorus compound, the effect is greatly influenced by the structure of the phosphorus compound as well as the phosphorus atom content, but the specific phosphinic acid derivative used in the present invention has a phosphorus atom in the ring member. Perhaps because of its natural structure, it is extremely thermally stable compared to phosphoric acid-based and phosphonic acid-based phosphorus compounds.
Moreover, it does not cause the polyester to gel, and exhibits a remarkable effect of imparting flame resistance. (Example) Next, the present invention will be described by giving examples. In addition, in the examples, the characteristic values of polyester were measured as follows. In the Examples, the intrinsic viscosity [η] of the polyester is a value measured at a temperature of 20.0° C. using an equal weight mixture of phenol and tetrachloroethane as a solvent. The content of phosphorus atoms in polyester is fluorescent X
Quantification was done by line method. ("Phosphorus content" indicates the amount of phosphorus atoms relative to the constituent units of polyester.) Flame resistance is measured by spinning and drawing yarn by a conventional method into a tubular knitted fabric, and measuring 1 g of the yarn into a length. Roll the wire into a 10.0 cm length, insert it into a 10.0 mm diameter wire coil, hold it at a 45 degree angle, and insert a micro burner (caliber 0.64
mm), and if the fire is extinguished by moving the fire source away, repeat the ignition again, calculate the number of ignitions required until all the samples are completely combusted, and calculate the number of ignitions (denoted as the number of flame contacts) for the five samples. expressed. Example 1 Synthesis of phosphorus compound (a) Thermometer, gas inlet, stirrer and diameter 3
cm, internal volume with 30 cm long Aline cooling tube
A 2000 cm ³ four-necked flask was charged with 212.2 g of the corresponding phosphinic acid and 900 g of ethyl cellosolve. Nitrogen gas was slowly blown in from the gas inlet, and the contents were heated while stirring until the temperature reached 80°C. During this process, the contents became a colorless and transparent solution. Next, 216 g of p-benzoquinone was added over 2 hours, and after stirring at 120°C for 2 hours, the mixture was allowed to cool and returned to room temperature, and the resulting crystals were filtered off and dried under reduced pressure to obtain white crystals. The crystals were purified by recrystallization with ortho-xylene. (The yield of phosphorus compounds is 92
It was %. ) This crystal was analyzed by infrared absorption spectroscopy, elemental analysis, and liquid gas chromatography, and as a result, it was confirmed to be the above-mentioned phosphorus compound (a). That is, in the infrared absorption spectrum, 1260
Absorption based on P=O of phosphinic acid in cm ^-1 , 3150
Broad absorption based on hydroxyl groups at ~3400 cm ^-1
Absorption based on the bond between phosphorus and phenyl groups was observed at 1440 cm ^-1 . Also, 2400 cm based on P-H of raw materials
Absorption near ^-1 and absorption near 1650 cm ^-1 due to C=O of p-benzoquinone were not observed. The result of elemental analysis is C = 49.8% (theoretical value 50.5
%), H=5.3% (theoretical value 5.1%). Synthesis of polyester Polyester is composed of 13 parts by weight of phosphorus compound (a) reacted with slightly excess acetic anhydride to form a diacetate, 174 parts by weight of terephthalic acid, 62 parts by weight of ethylene glycol, and dimethyltin maleate as a catalyst. 1×10 ⁻⁴ mol was added per 1 mol of the acid component to be reacted at 150 to 230° C. for 2 hours under a nitrogen stream. Then the temperature of the system was raised to 280℃,
The pressure was gradually reduced to 0.2 mmHg and the reaction was continued for 1 hour. The obtained polyester had [η] 0.65 and a phosphorus content of 6300 ppm (phosphorus residual rate 90.4%). Further, the number of times the fibers made of this polyester were exposed to flame was 4.6 times. Examples 2 to 4 Polyesters were produced in the same manner as in Example 1, except that the type and amount of the phosphorus compound added were changed. (All of the phosphorus compounds were converted into diacetates and used for polyester synthesis.) Table 1 shows the characteristic values of the obtained polyesters.

[Table] Example 5 16 parts by weight of dimethyl ester of phosphorus compound (f) obtained by reacting the corresponding phosphinic acid and dimethyl itaconate at 150°C in a nitrogen atmosphere for 4 hours, 174 parts by weight of terephthalic acid, and ethylene. glycol 69
Dimethyltin maleate is added as a catalyst in the weight part at 1x per mole of the acid component constituting the polyester.
Add 10 ^-4 mol and heat at 150 to 230°C under nitrogen stream for 2
Allowed time to react. Then the temperature of the system was raised to 280℃,
The pressure was gradually reduced to 0.2 mmHg, and the reaction was continued for 1 hour. The obtained polyester had [η] 0.56 and a phosphorus content of 6680 ppm (phosphorus residual rate 97.0%). Further, the number of times of flame contact with fibers made from this polyester was 4.8 times. Examples 6 to 9 Polyesters were obtained in the same manner as in Example 1 using the phosphorus compounds shown in Table 2. Table 2 shows the [η] and phosphorus content of the polyester obtained, and the number of times the fibers obtained from this polyester were exposed to flame.

[Table] Example 10 Phosphorus compound (i) 5.3 parts by weight, terephthalic acid 161
parts by weight, 74 parts by weight of ethylene glycol and 1.4 parts by weight of pentaerythritol, and 1 x 10 ^-4 mol of dimethyltin maleate as a catalyst per 1 mol of the acid component constituting the polyester, and heated at 150 to 230°C.
The mixture was reacted for 2 hours under a nitrogen stream. Next, the temperature of the system was raised to 280°C, and the pressure was gradually reduced to 0.2 mmHg, and the reaction was carried out for 2 hours. The obtained polyester had a [η] of 0.60 and a phosphorus content of 3800 ppm. Further, the number of times of flame contact with fibers made from this polyester was 3.4 times. Example 11 Phosphorus compound (n) 7.2 parts by weight, terephthalic acid 163
parts by weight, 74 parts by weight of ethylene glycol, 3.8 parts by weight of trimellitic anhydride, dimethyltin maleate as a catalyst, and acid component 1 constituting the polyester.
1×10 ⁻⁴ mol based on the mole was added, and the mixture was reacted at 150 to 230° C. for 2 hours under a nitrogen stream. Next, the temperature of the system was raised to 280°C, and the pressure was gradually reduced to 0.2 mmHg, and the reaction was carried out for 2 hours. The obtained polyester had a [η] of 0.63 and a phosphorus content of 3850 ppm. In addition, the number of times the fibers made of this polyester were exposed to flame was 3.2 times. (Effects of the Invention) According to the present invention, a polyester having excellent flame resistance and good physical properties can be easily and inexpensively produced.

Claims (1)

[Claims] 1. When producing a polyester from a dicarboxylic acid component, a diol component, and/or an oxycarboxylic acid component, a phosphorus compound represented by the following general formula [I] is added to a polyester whose phosphorus atom content is
A method for producing flame-resistant polyester, characterized by adding it to a concentration of 500 ppm or more. [Chemical formula] In formula [I], R ¹ is an ethylene group or 1,
2-phenylene group (which may have a substituent), A
represents a divalent or trivalent organic group, R ² represents a monovalent ester-forming functional group, and m and n are 1 or 2.