JPH045047B2 - - 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) Generally, polyester, especially polyethylene terephthalate, has excellent mechanical and chemical properties, so it is widely used as a textile for clothing, industrial use, etc.
It is widely used for films for magnetic tapes, photographs, condensers, etc., and for molded products such as bottles. Industrially, this polyethylene terephthalate is obtained by directly esterifying or transesterifying terephthalic acid or dimethyl terephthalate and ethylene glycol to obtain bis(β-hydroxyethyl) terephthalate (including its low polymer) in the presence of a catalyst. It is produced by polycondensation at high temperature and high reduced pressure to form a high polymer. 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. In particular, since polyethylene terephthalate is used in large quantities in clothing, carpets, curtains, vehicle seats, etc., there is an urgent need to establish countermeasures. In the past, various methods have been proposed for imparting flame resistance to polyester, and a method of incorporating a phosphorus compound into polyester is said to be effective (for example, Japanese Patent Publication No. 56-9178, Japanese Patent Application Laid-open No. 116052-1982). . However, when a phosphorus compound is contained in polyester, generally (1) gelation of the polyester occurs, (2) the melting point of the polyester decreases due to diethylene glycol by-product, (3) the residual rate of phosphorus is low, (4)
(5) Spinning, stretching,
There was a problem that toxic gas was easily generated during various processes such as molding. (Object of the Invention) An object of the present invention is to provide a method for producing a polyester that exhibits excellent flame resistance and has good color tone, moldability, physical properties, etc. (Structure of the Invention) The present invention achieves the above object and has the following structure. When producing polyethylene terephthalate or polyester mainly composed of polyethylene terephthalate, a phosphinic acid derivative represented by the following structural formula [] is added,
A method for producing flame-resistant polyester, which is characterized by a reaction. (In formula [], X ¹ and X ² are ester-forming functional groups. Also, the benzene ring may be substituted with a lower alkyl group or halogen.) Ester of X ¹ and X ² in formula [] Specific examples of forming functional groups include:

[Formula]-(R ² O) _n H and

[Formula] (R ¹ is a hydrogen atom or a lower alkyl group, R ² is a lower alkylene group,
m is an integer from 1 to 20, and n is an integer from 0 to 20. ) can be given. More specifically, R ¹ is H, -CH ₃ , -
CH ₂ , CH ₃ , R ² are -CH ₂ CH ₂ ^- ,

[Formula] is mentioned, and the most preferable phosphinic acid derivative is that X ¹ and X ² are acetyl groups.

It is a compound of [Formula]. The phosphinic acid derivative in the present invention is 9,10
^{X 1} , Compounds in which the part is H (hereinafter referred to as
PBQ/HCA using p-benzoquinone,
The product using o-benzoquinone is called OBQ/HCA. ) and introducing an ester-forming functional group into this part. For example, by heating and reacting carboxylic acid anhydrides corresponding to PBQ/HCA or OBQ/HCA.

[Formula] group can be introduced, and -
(R ² O) _n H or

[Formula] A group can be introduced. The amount of the phosphinic acid derivative added is 1×10 ^-3 to 3× per mole of the acid component constituting the polyester.
10 ⁻¹ mol, preferably 5×10 ⁻³ to 1×10 ⁻¹ mol,
More preferably, the amount is 5×10 ⁻³ to 5×10 ⁻² mol. If the amount added is less than this range, no flame resistance imparting effect will be observed, and if the amount added exceeds this range, the polycondensation reaction rate will slow down, the color tone will worsen, and the melting point will drop significantly. This results in the loss of the inherent advantages of polyethylene terephthalate. However, when used as a master polymer, the amount added may be large. The phosphinic acid derivative may be added before the completion of polycondensation of the polyester, but it is preferable to add it before the intrinsic viscosity of the polyester reaches 0.3, and optimally after the completion of the esterification or transesterification reaction. It is best to add it before starting the reaction. The phosphinic acid derivative is suitably added in the form of a powder or an ethylene glycol slurry. The polycondensation reaction is carried out under reduced pressure of about 0.01 to 10 mmHg.
It may be carried out at a temperature of 260 to 310°C, preferably 275 to 290°C, until a product having a predetermined intrinsic viscosity is obtained. Moreover, the polycondensation reaction is carried out in the presence of a catalyst,
Catalysts include conventionally commonly used metal compounds such as antimony, titanium, germanium, tin, zinc, and cobalt, as well as sulfosalicylic acid, o
-Organic sulfonic acid compounds such as sulfobenzoic anhydride are preferably used. The amount of catalyst added is 1x per mole of the acid component constituting the polyester.
10 ⁻⁵ to 1×10 ⁻² mol, preferably 5×10 ⁻⁵ to 5×
A suitable amount is 10 ^-3 mol, more preferably 1 x 10 ^-4 to 1 x 10 ^-3 mol. In the present invention, the base polyester is polyethylene terephthalate or a polyester mainly composed of polyethylene terephthalate, and the copolymer components include isophthalic acid, 4,4'-dicarboxybiphenyl,
Bis(4-carboxyphenyl)methane, 2,
2'-bis(4-carboxyphenyl)propane,
Acid components such as bis(4-carboxyphenyl) sulfone, bis(4-carboxyphenyl) ether, naphthalic acid, 4-hydroxyethoxybenzoic acid, 5-sodium sulfoisophthalic acid, adipic acid, trimellitic acid, neopentyl Examples include glycol components such as glycol, 1.4-cyclohexanedimethanol, and pentaerythritol. 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 also be present. (Example) Next, the present invention will be described with reference to Examples, but the present invention is not limited by these. In addition, in the examples, the characteristic values of polyester were measured as follows. (1) The intrinsic viscosity [η] of polyester was measured at a temperature of 20°C using a mixture of equal weights of phenol and tetrachloroethane as a solvent. (2) Glass transition temperature Tg and melting point of polyester
Tm was measured using a PerkinElmer DSC-2 differential calorimeter. (3) The content of diethylene glycol units is obtained by subjecting polyester to alcoholysis under refluxing methanol for 2 hours, quantifying ethylene glycol and diethylene glycol by gas chromatography, and expressing the content as mol% of diethylene glycol (denoted as DEG%) based on the total glycol. . (4) The phosphorus content in the polyester was determined by fluorescent X-ray method. (5) The color tone of polyester is determined at 150℃ after molding into granules.
Crystallize at ±2°C for 1 hour and use a colorimeter to measure L,
Evaluation was made by determining a and b values. The L value is the lightness (the larger the value, the brighter), the a value is the red-green hue (+ is reddish, - is greenish), and the b value is the yellow-blue hue (+ is yellowish, - is yellowish). As for the color tone of polyester, the larger the L value, the more a
The closer the value is to 0, and the smaller the b value is, the better, as long as it does not become extremely small. (6) Flame retardancy is determined by spinning polyester using a conventional method.
The yarn obtained by stretching is made into a tubular knitted fabric, and 1g of it is made into a length.
Roll it up to 10cm and insert it into a 10mm diameter wire coil.
Hold it at a 45 degree angle and ignite it with a micro burner (0.64mmφ) from the bottom end.If the fire is extinguished by moving away from the fire source, repeat the ignition and calculate the number of ignitions required until all the samples are completely burned. It is expressed as the average number of ignitions (denoted as the number of flame contacts) for each sample. (The Fire Service Act standard is at least 3 times or more.) Example Terephthalic acid and ethylene glycol were esterified by a conventional method to obtain an esterified product with an esterification reaction rate of 95%. This esterified product was charged into a polycondensation reactor, and the phosphinic acid derivatives shown in Table 1 and 2 x 10 ^-4 mol of antimony trioxide were added per 1 mol of the acid component, and the mixture was stirred at 280°C under reduced pressure. A polycondensation reaction was carried out for 3 hours. The characteristic values of the obtained polyester are shown in Table 1. In Table 1, the reference example shows ordinary polyethylene terephthalate containing no phosphorus compound.

[Table] In Table 1, phosphinic acid derivatives A to D indicate the following. A: Compound obtained by reacting PBQ/HCA and acetic anhydride at a molar ratio of 1:4 under reflux [where X ¹ and X ² are

Compound of [Formula] B: Compound using OBQ/HCA instead of PBQ/HCA in A C: Compound obtained by reacting the sodium salt of PBQ/HCA with epichlorohydrin [where X ¹ , X ² are

Compound of [Formula]] D: Compound obtained by reacting PBQ/HCA with ethylene oxide [Compound in which X ¹ and X ² are -CH ₂ CH ₂ OH] (Effects of the invention) As described above, the present invention According to this method, it is possible to easily produce a polyester having excellent flame resistance and good color tone. In the polyester obtained by the method of the present invention, the phosphorus compound is chemically bonded to the polyester, so the phosphorus compound falls off during post-processing such as dyeing or washing during use, resulting in a decrease in flame resistance. It exhibits permanent flame resistance.

Claims (1)

[Claims] 1. A method for producing flame-resistant polyester, which comprises adding and reacting a phosphinic acid derivative represented by the following structural formula [] when producing polyethylene terephthalate or a polyester mainly composed of polyethylene terephthalate. . (In the formula [], X ¹ and X ² are ester-forming functional groups. Also, the benzene ring may be substituted with a lower alkyl group or a halogen.) 2 Phosphinic acid derivatives are X ¹ in the formula [] ，
2. The method according to claim 1, wherein X ² is a compound having an acetyl group.