JPS62185710A - Production of flame-resistant polyester - Google Patents

Abstract

PURPOSE:To obtain at a low cost a polyester which can show excellent flame resistance and has a high glass transition point and good shade, moldability, physical properties, etc., by adding a specified phosphorus compound to the reaction system for the production of a polyester. CONSTITUTION:A phosphorus compound of the formula [wherein R<1> is an ethylene group or a 1,2-phenylene group (which may have a substituent), A is a bivalent or trivalent organic group, R<2> is a monovalent esterifiable functional group and m and n are each 1 or 2] in such an amount that the phosphorus content of the polyester is 500ppm or above is added to the reaction system for the production of a polyester from a dicarboxylic acid component and a diol component and/or a hydroxycarboxylic acid component. Said phosphorus compound can be added in an arbitrary stage from the esterification or transesterification to the initial stage of the polycondensation reaction.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) 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 molded products such as bottles. It is widely used for purposes.

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 polyester contains a phosphorus compound,
In general, (1) gelation of the polyester occurs; (2)
Addition of a phosphorus compound lowers the melting point and glass transition point of polyester. (3) Low residual rate of phosphorus compounds (
4) The color tone of polyester deteriorates.

(5) There is a problem in that toxic gases are 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 eliminates the above problems.
This phosphorus compound is expensive, and if it is added in an amount sufficient to impart sufficient flame resistance to polyester, it will increase 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 two-tone tone, moldability, and physical properties. 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 (1) is added such that the phosphorus atom content in the polyester is 500 ppm or more. A method for producing flame-resistant polyester, characterized by adding the following:

0=P-0・[I]A-(R2
) n In formula (1), R' is an ethylene group or a 1,2-phenylene group (which may have a substituent), A is a divalent or trivalent organic group, and R2 is a monovalent ester-forming functional group. Indicates the group,
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-cyclohexane dimetatool, 1,4-butanediol.

Pentaerythritol or the like may be used in combination as a copolymerization component.

A in the phosphorus compound (1) is a divalent (n=1) or trivalent (n=2) organic group, and specific examples include the following tertiary groups.

Methylene group, ethylene group, isopropylidene group.

Alkyl groups such as cyclohexylene groups, alkylidene groups,
p-phenylene! , m-phinidine group, 1,4-naphthalene group, arylene such as 2,6-naphthalene group, l, L
2. Alkanetriyl group such as 3-propanetriyl group,
Trivalent cyclohexane ring 1. Trivalent benzene ring group or 3
valent naphthalene ring group.

Moreover, as R2 in phosphorus compound (1).

Examples include hydroxyl groups, carboxyl groups, and ester-forming derivatives thereof.

Note that the 1,2-phenylene group of R1 is a halogen atom,
It may have a hydrocarbon group having 1 to 20 carbon atoms or a halogenated hydrocarbon group as a substituent.

Specific examples of -A-(R")n include the following primary groups, those obtained by converting these carboxyl groups into lower alkyl ester groups such as methyl and ethyl, or acid anhydride groups, and those obtained by converting hydroxyl groups into acetyl ester groups or acid anhydride groups. Examples include those converted to hydroxyethoxy groups.

Specific examples of the phosphorus compound [I] include the following compounds and their ester-forming HMR forms.

In addition, among the above-mentioned phosphorus compounds, those having a phenolic hydroxyl group have a weak ester-forming ability as they are, so it is desirable to convert them into ester-forming derivatives such as acetyl esters and use them for the reaction.

The phosphorus compound [I] is a compound represented by the following formula (n) (referred to as phosphinic acid) and p-benzoquinone.

1. Either quinones such as 4-naphthoquinone are reacted with heat in a solvent such as ethyl cellosolve, and if necessary, the hydroxyl group of the reaction product is converted to other ester-forming functional groups, or itaconic acid, By causing an addition reaction between a compound having a double bond and an ester-forming functional group, such as dimethyl itaconate, 2-butene-1,4-diol, and 2-butene-1,4-diol diacetate, and phosphinic acid. can get.

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 copolyester polyesters, but they may also be used in the form of monomers, oligomers, or polymers reacted with an acid component such as terephthalic acid or isophthalic acid.

The amount of the phosphorus compound added is 500 ppm or more as phosphorus atoms based on the polyester, preferably 1000 to 110 ppm.
It is necessary to adjust the content to 000 pp.

(Determine the amount added by taking into account that some of the phosphorus compound will scatter during polycondensation.) If the amount of phosphorus compound is less than 500 ppm, the flame resistance will be insufficient, and if it is too large, the strength properties required for polyester will not be maintained. Gelation may occur before the required degree of polymerization is reached.

Polyester's original good physical properties are impaired, etc.
During operation, problems may arise regarding the 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 initial stage of the polycondensation reaction. be able to.

Note that polyester with a high degree of polymerization may not be obtained depending on the type of phosphorus compound and the timing of addition.

For example, when using a phosphorus compound with one ester-forming functional group, it may act as a terminal capping agent.
In such a case, consideration should be given to the combined use of a polyfunctional compound such as pentaerythritol, trimellitic acid, trimesic acid, pyromellitic acid, etc.

The polycondensation reaction when producing polyester is 1 usually 0.0
260-310°C under reduced pressure of about 1-10g and 11g.

Preferably, the polymerization is carried out at 275 to 290°C until a predetermined degree of polymerization is obtained.

Further, the 9-polycondensation reaction is carried out in the presence of a catalyst.

As catalysts, antimony, titanium, germanium, tin, zinc, and aluminum, which are commonly used in the past, are used. Magnesium, calcium, manganese.

In addition to metal compounds such as cobalt, sulfosalicylic acid,
- Preferably used sulfonic acid compounds such as sulfobenzoic anhydride. The amount of catalyst added is based on 1 mole of the acid component constituting the polyester.

1xto-' to 1x104 mol, preferably 5x104
~5X10-'moles, optimally lXl0-'~3X10
-3 mol is appropriate.

Also used in the present invention are stabilizers such as hindered phenol compounds, cobalt compounds, and 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 is a fiber depending on its properties.

Used for manufacturing molded products such as films and bottles.

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 exposed to flame, promoting melting and falling, resulting in good flame resistance. It is recognized that this phenomenon occurs.

In addition, 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.9 Perhaps because the phosphorus atom is a ring member in the specific phosphinic acid derivatives used in the present invention, phosphoric acid derivatives and phosphonic acid It is extremely thermally stable compared to other phosphorus compounds, does not cause gelation of polyester, 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 addition, 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 the polyester was determined by fluorescent X-ray method. (The "phosphorus content" refers to the amount of phosphorus atoms relative to the constituent units of polyester.) Flame resistance is determined by spinning and drawing yarn by a conventional method into a tubular knitted fabric, and measuring 1 g of the yarn into a tube-knitted fabric with a length of 10. Round to 0 cm and 10
．． Insert it into a wire coil with a diameter of 0 mm, hold it at a 45 degree angle, and insert a micro burner (diameter 0.64 mm) from the bottom end.
If the flame was ignited and extinguished by moving the fire source away, the flame was ignited again, and the number of ignitions required until all the samples were completely combusted was calculated and expressed as the number of ignitions (denoted as the number of flame contacts) for the five samples. .

Example 1 Phosphorus compound (a) input h' Thermometer, gas blower, stirrer and 3cm diameter.

Aline with a length of 30 cm, internal volume 200 with cooling pipe
0 cnt four-loaf flask, the corresponding phosphinic acid 2
12.2 g and 900 g of ethyl cellosolve were charged. Slowly blow in nitrogen gas from the gas inlet.

While stirring, the contents were heated to 80°C.

During this process, the contents became a colorless and transparent solution. Then,
216 g of p-benzoquinone was added over 2 hours, and 12
After stirring at 0° 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 the phosphorus compound was 92%.) The results of analyzing this crystal by infrared absorption spectrum, elemental analysis, and liquid gas chromatography.

It was confirmed that it was the phosphorus compound (a).

That is, in the infrared absorption spectrum, 1260c
Absorption based on p=o of phosphinic acid in m −', 31
Broad absorption based on hydroxyl groups was observed at 50 to 3400 cm-', and absorption based on the bond between phosphorus and phenyl groups was observed at 1440 cm-'. Also, based on P −H of the raw material
No absorption was observed near 2400 cm-' and <1650 cm-' based on C=O of p-benzoquinone.

The result of elemental analysis is C=49.8% (theoretical value 50.5
%).

H=5.3% (theoretical value 5.1%).

Synthesis of polyester Phosphorus compound (a) was reacted with a slight excess of acetic anhydride to form a diacetate, 13 parts by weight, 17 parts by weight of terephthalic acid.
4 parts by weight and 62 parts by weight of ethylene glycol were added with 1X10-' mol of dimethyltin maleate as a catalyst per 1 mol of the acid component constituting the polyester.
The reaction was carried out at 230'C for 2 hours under nitrogen flow. Next, the temperature of the system was raised to 280°C, and the pressure was gradually reduced to 0.2
The reaction was continued for 1 hour.

The obtained polyester has a [η) of 0.65. The phosphorus content was 6300 ppm (phosphorus residual rate 90.4%).

In addition, the number of times of flame contact of fibers made from this polyester is 4.6
It was 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 subjected to polyester synthesis.) Table 1 shows the characteristic values of the obtained polyesters.

Table 1 Example 5 Corresponding phosphinic acid and dimethyl itaconate at 150%
16 parts by weight of dimethyl ester of phosphorus compound (f) obtained by reacting for 4 hours at ℃ under a nitrogen atmosphere, 1 part by weight of terephthalic acid.
To 74 parts by weight and 69 parts by weight of ethylene glycol, dimethyltin maleate was added as a catalyst to 1 x IO: 4 mol per mol of the acid component constituting the polyester, and 150
The reaction was carried out at ~230°C for 2 hours under a nitrogen stream. The temperature of the system was then raised to 280°C.

The pressure was gradually reduced to 0.2wm11g, and the reaction was continued for 1 hour.

The obtained polyester had a [η) of 0.56. The phosphorus content was 16,680 ppm (phosphorus residual rate 97.0%).

In addition, the number of times of flame contact of fibers made from this polyester is 4.
It was 8 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 polyester from a dicarboxylic acid component, a diol component and/or an oxycarboxylic acid component,
A method for producing a flame-resistant polyester, which comprises adding a phosphorus compound represented by the following general formula [I] so that the phosphorus atom content in the polyester is 500 ppm or more. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [I] In the formula [I], R^1 is an ethylene group or 1,2-
A is a phenylene group (which may have a substituent), A is a divalent or trivalent organic group, R^2 is a monovalent ester-forming functional group, and m and n are 1 or 2.