TW201343712A - Method for producing flame-retardant polyester, and flame-retardant master batch - Google Patents

Abstract

Provided is a method for producing a flame-retardant polyester which contains phosphorous at a high concentration through copolymerization, has a high degree of polymerization, a low degree of copolymerization of a diethylene glycol component, and rarely undergoes discoloration. A method for producing a flame-retardant polyester, comprising a step of agitating a composition comprising components (A) to (E) mentioned below while heating: (A): a phosphorous compound represented by general formula (1); (B): an unsaturated dicarboxylic acid or an ester-forming derivative thereof; (C): a saturated aliphatic polyhydric alcohol mainly composed of ethylene glycol and/or an ester-forming derivative thereof; (D): a polycarboxylic acid other than the component (B) or an ester-forming derivative thereof; and (E): an acetic acid metal salt.

Description

Method for producing flame retardant polyester and flame retardant masterbatch

The present invention relates to a process for producing a flame retardant polyester containing a high concentration of phosphorus. The flame retardant polyester obtained by the method of the present invention is useful as a flame retardant masterbatch.

It is known that organic phosphorus represented by 9,10-dihydro-9-oxa-phosphaphenanthrene-10-oxide (9,10-dihydro-9-oxa-phosphaphenanthrene-10-oxide) The compound (hereinafter also referred to as DOP) is copolymerized with a polyester to obtain a flame retardant containing a high concentration of phosphorus and which is less likely to bleed out. Further, it is known that a copolymerized polyester having a high phosphorus content in which a phosphorus compound such as DOP is copolymerized is used as a flame retardant masterbatch, and a flame retardant masterbatch is blended in a thermoplastic resin (base resin) and melted and kneaded to give difficulty. Technology of flammability (refer to Patent Document 1).

In the method of producing a polyester in which a phosphorus compound is copolymerized, it is known to use a method of using a non-ester forming specific phosphorus compound in addition to a method of synthesizing a phosphorus compound having an ester-forming property (see Patent Document 1). Refer to Patent Document 2 and Patent Document 3).

Patent Document 2 discloses a method for producing a flame retardant polyester in which a specific amount of a specific phosphorus compound and a specific unsaturated aliphatic compound are added before an esterification reaction or an esterification reaction. Further, in Patent Document 3, it has been disclosed that a specific phosphorus compound, a specific unsaturated carboxylic acid or an ester-forming derivative thereof, and a specific amine are coexisted in a reaction system of an esterification reaction or a transesterification reaction. A method for producing a fire-resistant polyester of a compound. According to these methods, it is considered that since it is not necessary to separately produce an ester-forming phosphorus compound copolymerizable with the polyester, the flame retardant polyester can be considerably reduced. Manufacturing costs.

[Previous Technical Literature] [Patent Document]

[Patent Document 1] Japanese Patent No. 3934133

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2000-212266

[Patent Document 3] Japanese Patent No. 4006629

However, the inventors of the present invention have studied the production of a polyester resin containing a high concentration of phosphorus of about 30,000 ppm or more by copolymerization by the method described in Patent Document 2 and Patent Document 3, and it has been found that the following phenomenon occurs: phosphorus compound The polyester resin which deactivates the polymerization catalyst and is difficult to obtain a high degree of polymerization, the copolymerization of the by-produced diethylene glycol during the polymerization causes the glass transition temperature of the obtained polyester resin to decrease, and the aggregation due to the amine compound The ester resin is colored. Moreover, it is understood that if a flame retardant polyester having such a phenomenon is used as a flame retardant masterbatch, bending strength, bending elastic modulus, tensile strength, load deflection temperature, etc. of the molten mixture of the flame retardant masterbatch and the base resin are used. The mechanical properties are remarkably lowered as compared with the base resin, and there is a tendency to cause coloration, and there is a problem in that high mechanical properties or low-coloring or non-staining applications are required.

In view of the above, an object of the present invention is to provide a method for producing a flame retardant polyester which is produced by copolymerization and which contains a high concentration of phosphorus but is a high degree of polymerization and a diethylene glycol component. A flame retardant polyester having a low polymerization ratio and low coloration.

The present inventors have intensively studied to achieve the above problems, and as a result, it has been found that a specific phosphorus compound, an unsaturated carboxylic acid or an ester-forming derivative thereof, and a metal acetate salt are formed by derivatization with a polyvalent carboxylic acid or an ester thereof. Coexisting with a saturated aliphatic diol or its ester-forming derivative and heating and mixing Further, the present invention has been completed by containing a high concentration of phosphorus by copolymerization and producing a flame retardant polyester having a high degree of polymerization and a low copolymerization ratio of a diethylene glycol component and having little coloration.

That is, the present invention is as follows.

<1> A method for producing a flame retardant polyester, which comprises the steps of heating and mixing a composition containing the following components (A) to (E), and component (A): a compound of the following formula (1) Phosphorus compound (B) component: unsaturated dicarboxylic acid or its ester-forming derivative, (C) component: saturated aliphatic polyol and/or ester-forming derivative mainly composed of ethylene glycol, (D) Component: a polyvalent carboxylic acid other than the component (B) or an ester-forming derivative thereof, and (E) component: a metal acetate.

<2> A method for producing a flame retardant polyester, comprising: a step (P) of heating and mixing a composition containing the following components (A) to (E); and (A) component: a general formula (1) a phosphorus compound, (B) component: unsaturated dicarboxylic acid or its ester-forming derivative, (C) component: saturated aliphatic polyol and/or ester-forming derivative mainly composed of ethylene glycol, (D) Component: a polyvalent carboxylic acid other than the component (B) or an ester-forming derivative thereof, (E) component: a metal acetate; and a component obtained in the step (P): a component (F): a polymerization catalyst, followed by The step (Q) of heating and depressurizing is performed.

<3> The method for producing a flame retardant polyester according to <1> or <2>, wherein the component (B) is maleic acid, fumaric acid, and/or itaconic acid.

<4> A flame retardant masterbatch comprising a flame retardant polyester and a metal acetate, and the flame retardant polyester is based on a total polybasic component and a total polyol component constituting the flame retardant polyester. a total of 200% by mole, 20 to 60% by mole of a dicarboxylic acid component having an organic group represented by the following formula (2), a total of 0.05 to 3 mol% of a trivalent or higher polyvalent carboxylic acid component, and / or a trihydric or higher polyhydric alcohol component, 37 to 79.95 mol% of an aromatic dicarboxylic acid component, and a remaining portion of an aliphatic diol component. The Co-b value is -5 to 20, and the Co-L value is 50 or more.

<5> The flame retardant masterbatch according to <4>, wherein a copolymerization ratio of the diethylene glycol component constituting the flame retardant polyester resin is 30 mol% or less.

According to the present invention, it is possible to inexpensively produce a flame retardant polyester which contains a high concentration of phosphorus by copolymerization, has a high degree of polymerization, and has a low copolymerization ratio of a diethylene glycol component and a small coloration. Again, by using The flame-retardant polyester obtained by the production method of the present invention can be used as a flame-retardant masterbatch to obtain a flame-retardant thermoplastic resin composition which does not impair the mechanical properties of the base resin and which has low transparency and high transparency.

[Formation of the Invention]

The invention is explained in more detail below.

The present invention relates to a method for producing a flame retardant polyester comprising: a phosphorus compound containing the component (A): a phosphorus compound of the formula (1), and a component (B): an unsaturated dicarboxylic acid or an ester-forming derivative thereof, (C) component: a saturated aliphatic diol or an ester-forming derivative thereof, (D) component: a polyvalent carboxylic acid other than the component (B) or an ester-forming derivative thereof, and (E) component: a composition of a metal acetate The step (P) of heating and mixing. Moreover, the method for producing a flame retardant polyester comprises the step (Q) of adding a component (F): a polymerization catalyst to the composition obtained in the step (P), followed by heating and pressure reduction. The flame retardant polyester of the present invention is a copolymer of the component (B) of the component (A) and the component (C) and the component (D).

In the method for producing a flame retardant polyester of the present invention, it is necessary to form a phosphorus compound of the formula (1) of the component (A), an unsaturated carboxylic acid of the component (B) or an ester thereof, and a component (E). The metal acetate salt coexists before the esterification reaction or the transesterification reaction. By subjecting such a step, the reaction between the component (A) and the component (B) can be rapidly carried out, and even in the case where the esterification reaction and/or the transesterification reaction are carried out under high temperature and high vacuum, the reaction can be carried out. In the initial stage, the thermally stable ester-forming phosphorus compound derivative is rapidly formed, so that the decrease in the copolymerization ratio due to the volatilization of the component (A) and the crosslinking formation due to the reaction of the component (B) can be suppressed. And the accompanying gelation.

Further, it is preferred to add a polymerization catalyst of the component (F) after the esterification reaction and the transesterification reaction. By adding the component (F) in such a reaction stage, the phosphorus compound of the component (A) does not deactivate the polymerization catalyst of the component (F), and tends to produce a polyester having a higher degree of polymerization at a low cost.

The phosphorus compound of the formula (1) of the component (A) used in the present invention is 9,10-dihydro-9-oxo-10-phosphaphenanthrene-10-oxide (DOP). Although DOP has an effect of imparting fire resistance to polyester, it does not have an ester forming ability per se, and therefore is inert to the ester formation reaction, and cannot be directly used as a copolymerization component of polyester. Therefore, in the production step of the polyester, the present invention forms a thermal stability by allowing DOP, an unsaturated carboxylic acid or an ester-forming derivative thereof to coexist in the reaction system during the esterification reaction or the transesterification reaction. The ester-forming phosphorus compound derivative is obtained by copolymerizing the resulting ester-forming phosphorus compound derivative with a polyester in a polycondensation reaction step to produce a flame-retardant polyester having a DOP residue in a side chain. Further, in the present invention, the direct esterification method which undergoes the esterification reaction is preferred from the viewpoint of the cost of the raw material.

The unsaturated carboxylic acid of the component (B) used in the present invention or an ester-forming derivative thereof may, for example, be an unsaturated monocarboxylic acid such as acrylic acid, crotonic acid or methacrylic acid; maleic acid, fumaric acid or zhongkang; An unsaturated dicarboxylic acid such as acid, citraconic acid or itaconic acid; an alkyl ester such as a methyl ester or an ethyl ester of the above unsaturated carboxylic acid; an acid anhydride such as maleic anhydride, citraconic anhydride or itaconic anhydride; . Among these, an unsaturated dicarboxylic acid such as maleic acid, fumaric acid or itaconic acid or an ester-forming derivative thereof is preferred. These compounds may be used alone or in combination of two or more.

In the method for producing a flame retardant polyester of the present invention, the phosphorus compound of the formula (1) of the component (A) and the unsaturated carboxylic acid of the component (B) or an ester-forming derivative thereof are substantially equivalent. Ear use is preferred, but it does not matter if either side is in the range of 20 mol% or less. However, if the excess of the component (A) exceeds 20 mol% with respect to the component (B), the polymerization catalyst may be deactivated, and the polymerization may take a long time or the inactivation of the catalyst may cause the color tone of the polyester to deteriorate or become The tendency of the cause of the filth. On the other hand, when the amount of the component (A) is more than 20 mol% with respect to the component (B), the amount of the unsaturated carboxylic acid is excessive, which tends to cause gelation or coloration of the polyester. That is, in the present invention, each of the amounts of the component (A) and the component (B) is preferably in the range of 80 to 120 mol% of either of the other components, and particularly preferably 85 to 115 mol%. range.

In the flame retardant polyester of the present invention, copolymerization of 20 to 60 mol% of the component (A) has the formula (2) The organic dicarboxylic acid component shown is preferred. When the copolymerization ratio of the dicarboxylic acid component having the organic group represented by the general formula (2) is less than 20 mol%, in order to sufficiently exhibit the flame retardancy effect, it is necessary to increase the blending ratio of the flame retardant masterbatch to the base resin. For this reason, the mechanical properties of the blend tend to become much worse than the mechanical properties of the base resin, which is not preferable. In addition, when the copolymerization ratio of the dicarboxylic acid component having the organic group represented by the general formula (2) is more than 60 mol%, it is difficult to obtain a flame retardant polyester having a high degree of polymerization, and thus it is preferable to do so. The mechanical properties of the mixture are likely to become much worse than the mechanical properties of the base resin, which is not preferable.

The component (D) of the present invention is a polyvalent carboxylic acid other than the component (B) or a derivative thereof. It is preferred that the component (D) is mainly composed of an aromatic dicarboxylic acid component or an ester-forming derivative thereof. Examples of the aromatic dicarboxylic acid component include citric acid, 1,3-naphthalene dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, and 2 , 7-naphthalenedicarboxylic acid, o-decanoic acid, m-decanoic acid, 5-(alkali metal)sulfoisophthalic acid, biphenyl acid, 4,4'-biphenyldicarboxylic acid, 4,4'-dicarboxyl An aromatic dicarboxylic acid such as diphenylguanidine, 4,4'-dicarboxydiphenyl ether, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid or stilbene dicarboxylic acid Among the above-mentioned ester-forming derivatives, among these aromatic dicarboxylic acids, citric acid or 2,6-naphthalene dicarboxylic acid is preferred.

The component (C) of the present invention is a saturated aliphatic polyol and/or ester-forming derivative mainly composed of ethylene glycol. Examples of the component (C) include ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, diethylene glycol, triethylene glycol, 1,2-butanediol, and 1,3-butanediol. , 2,3-butanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,2-cyclohexanediol, 1,3 - cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,4-ring An aliphatic diol such as hexane diethanol, 1,10-nonanediol, 1,12-dodecanediol, polyethylene glycol, polypropylene glycol or polybutylene glycol. Among these diols, B The diol having a carbon number of 2 to 5 such as diol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, etc., from the viewpoint of improving the glass transition point (Tg) of the flame retardant polyester Preferably, the ethylene glycol is preferably 50 mol% or more.

Further, the flame retardant polyester of the present invention is a trivalent or higher alcohol such as a trivalent or higher carboxylic acid such as trimellitic acid, trimellitic anhydride or pyromellitic acid, or glycerin, trimethylolpropane or pentaerythritol. Copolymerization of trifunctional or higher polyfunctional components, etc., from the point of enhancing the viscosity of the flame retardant polyester In particular, the polyvalent carboxylic acid component having a total of 0.05 to 3 mol % of a total of 200 to 3 mol % of the total polyhydric acid component and the total polyhydric alcohol component constituting the flame retardant polyester and/or Or a trihydric or higher polyhydric alcohol component is preferred. When the total amount of the polyvalent carboxylic acid and/or the polyhydric alcohol is less than 0.05 mol%, it is difficult to increase the degree of polymerization to the intended viscosity, and if it is 3 mol% or more, the excessive branching of the polyester may become excessive, which may occur. The case of gelation. The total amount of the polycarboxylic acid and/or the polyhydric alcohol is preferably 0.05 to 3 mol%, more preferably 0.1 mol% to 2 mol%.

The metal acetate of the component (E) of the present invention is preferably an alkali metal salt, an alkaline earth metal salt, a transition metal salt or the like of acetic acid, and particularly, sodium acetate, lithium acetate, and the like from the viewpoint of suppressing the color tone of the polyester. Cobalt acetate or the like is preferred. In the case where sodium acetate is blended, it is preferable that the sodium atom is 5 to 50 ppm of sodium acetate, more preferably 10 ppm to 30 ppm, with respect to the flame retardant polyester. When it is 5 ppm or less, the effect of suppressing the copolymerization ratio of the diethylene glycol component tends to be lowered. Moreover, when it is 50 ppm or more, the resin coloring tends to be enhanced. Further, in order to reduce the Co-b of the flame retardant masterbatch, cobalt oxide having a cobalt atom of 5 to 50 ppm is preferably added, and more preferably 10 ppm to 30 ppm. Below 5 ppm, the effect of lowering Co-b is small. Moreover, when it is 50 ppm or more, the resin becomes blue to the extent that it is strong.

The polymerization catalyst of the component (F) of the present invention is not particularly limited, and when a catalyst such as a ruthenium compound or an aluminum compound is used, the effect of suppressing blackening of the flame retardant polyester can be obtained, and a polymer having a high Co-L value can be obtained. The tendency of the ester is better. In particular, from the viewpoint of high polymerization activity, a ruthenium compound is preferred.

In the method for producing a flame retardant polyester of the present invention, the metal acetate salt added to the reaction system before the esterification reaction or the transesterification reaction remains even in the polycondensation step. Since the residual metal acetate salt makes the reaction system weakly alkaline, it inhibits the by-production of diethylene glycol. By such an action, the effect of lowering the copolymerization ratio of diethylene glycol to the flame retardant polyester can be exerted. The diethylene glycol component constituting the aliphatic polyol component of the flame retardant polyester of the present invention is preferably 30 mol% or less. When the copolymerization ratio of the diethylene glycol component is increased, the Tg of the flame retardant polyester tends to be lowered, and when it is 30 mol% or more, there is a fear that the mechanical properties are lowered or the blocking is caused during drying.

The flame retardant masterbatch of the present invention must contain the flame retardant polyester of the present invention and the metal acetate salt, Other resins, compatibilizing agents, and/or various additives may be further blended. For example, by blending a pigment or an antioxidant as an additive, the flame-retardant masterbatch can be added with a coloring or anti-oxidation function. Moreover, by blending another resin or a compatibilizing agent having high compatibility with the base resin, it is expected to have an effect of simplifying the melt-kneading step or homogenizing the flame-retardant resin composition.

The moisture content of the flame retardant masterbatch of the present invention is preferably 0.1% by weight or less, further preferably 0.05% by weight or less, and further preferably 0.03% by weight or less. When the water content is 0.1% by weight or less, it is sufficiently dried, and blocking or decomposition tends to be suppressed.

By mixing the flame retardant masterbatch of the present invention and a thermoplastic resin (base resin), a flame retardant thermoplastic resin composition containing a predetermined amount of phosphorus can be produced.

The L value (whiteness) measured by the Hunter color and color difference meter of the flame retardant masterbatch of the present invention is preferably 50 or more, and more preferably 55 or more. Further, it is preferable that the b value measured by the Henry characteristic meter is -5 or more and 20 or less, and further preferably 15 or less and 10 or less. By using the method for producing a flame-retardant polyester of the present invention, it is possible to obtain a low-coloring or non-colored, flame-retardant masterbatch having a high whiteness and a low yellow color. Further, the flame retardant masterbatch of the present invention is not only less colored but also excellent in coloring resistance. Therefore, the whiteness of the thermoplastic resin composition obtained by blending the flame retardant masterbatch of the present invention with the base resin is almost the same as that of the general base resin before the blending of the flame retardant master batch.

The blending ratio of the flame retardant masterbatch to the base resin can be appropriately adjusted according to the desired phosphorus content of the blended flame retardant thermoplastic resin composition, and is usually 0.5 to 90% by weight of the flame retardant thermoplastic resin composition. good. Further, it is preferably from 1 to 50% by weight, and further preferably from 10 to 30% by weight. The phosphorus content in the flame retardant thermoplastic resin composition is not particularly limited, but it is effective from the viewpoint of flame retardancy, 1000 ppm or more, further 2000 ppm or more, and further 4000 ppm or more. In the prior art, a flame retardant thermoplastic resin composition capable of simultaneously satisfying a high phosphorus concentration, a high polymerization degree, a high glass transition temperature, and a phosphorus content satisfying the above range of the flame retardant masterbatch is not satisfied. The strength of the molded article during the forming process is weakened, or the cooling time required for extracting the molded article from the mold is increased, so that it is not practical. However, the present invention can easily produce a molded article having sufficient strength with high productivity.

As the base resin to which the flame retardant master batch of the present invention is blended, any thermoplastic resin can be used. Examples of any thermoplastic resin may, for example, be a polyolefin resin, a polystyrene resin, or an acrylonitrile. Butadiene/styrene copolymer resin, acrylonitrile. Styrene copolymer resin, (meth)acrylic acid. Styrene copolymer resin, (meth)acrylic resin, butadiene. Styrene copolymer resin, polycarbonate resin, polyamide resin, polyarylate resin, polyfluorene resin, polyallyl oxime resin, polyether oxime resin, polyether oxime imide resin, polyimine resin, Polyester resin such as polyethylene terephthalate, polybutylene phthalate, polybutylene phthalate, polylactic acid, etc.; polyester carbonate resin, polyester ether resin, polyurethane resin And such mixed resins and the like, especially in the case of being suitable for a polyester resin, are preferable from the viewpoint of compatibility.

[Examples]

The invention is specifically illustrated by the following examples, but the invention is not limited by the examples. In addition, each measurement in this specification is performed by the following method.

(1) Phosphorus concentration: A sample of 7 g of a sample resin was weighed by a small electronic balance. The aluminum ring was placed on the use surface (mirror surface) of the ferrotype plate, and the weighed sample was placed therein. The iron plate loaded with the sample was placed in a hot air dryer at 270 ° C and heat treated for 20 minutes. After cooling, each aluminum ring and the molten sample were peeled off from the iron plate to obtain a plate-like sample having a thickness of about 5 mm. Fluorescence X-ray analysis was performed on the non-contact side of the iron plate of the plate-like sample using a fluorescent X-ray analyzer system 3270 manufactured by Rigaku Corporation to determine the phosphorus concentration.

(2) Ultimate viscosity: The ultimate viscosity of the sample was measured at 30 ° C in a phenol/1,1,2,2-tetrachloroethane mixed solution (weight ratio (3/2)).

(3) Color value: The color value of the sample was measured using a Hen's characteristic difference meter. The larger the Co-L value, the more white The stronger the degree, the larger the Co-b value indicates the stronger the degree of yellowing.

(4) Glass transition point temperature (Tg): using a differential scanning calorimeter (DSC), annealing from room temperature to 200 ° C at a temperature increase rate of 20 ° C / min, and quenching with liquid nitrogen, at 20 ° C / min The temperature increase rate was raised from 0 ° C to 200 ° C, and the intersection of the baseline and the tangent to the inflection point was measured. In the sample, 5 mg of the sample was placed in an aluminum lid-type container and pinched.

(5) polymerization time

The time taken until the limit viscosity (IV) of the polyester rises to 0.67 (target value) ± 0.03 dl/g from the time when the internal pressure of the reaction tank is lowered to 10 hPa in the polycondensation step is regarded as the polymerization time. However, the measurement was performed with an upper limit of 240 minutes.

(6) Pelletizing processing method

After the end of the polycondensation step, the molten polyester is discharged from the nozzle under nitrogen pressure, extruded into a strand shape, and immersed in cooling water in a water tank equipped with cooling water, and then a wire cutter is used. The pellet is pelletized. A roughly cylindrical pellet having a diameter of about 3 mm and a length of about 3 mm was obtained.

The following are examples and comparative examples of the polyester resin composition for a flame retardant masterbatch according to the present invention.

[Example 1]

The polybasic acid component and the phosphorus compound shown in Table 1 were fed at the ratios shown in Table 1, and the polyol component shown in Table 1 was fed so as to have a molar ratio of 2 mol equivalent to the total polybasic acid component under pressure. The temperature was raised to 240 ° C to carry out an esterification reaction. In the esterification reaction, 200 ppm of cerium oxide was added to the resin in terms of ruthenium atom, and the mixture was transferred to a polycondensation reaction tank, and the temperature was raised to 265 ° C for 60 minutes while slowly and in parallel. Reduce the pressure and reach below 1.3hPa after 60 minutes. Under the conditions, stirring was carried out while the polycondensation reaction was carried out until the polyester had a target ultimate viscosity (0.67 ± 0.03 dl/g) to obtain a polyester containing a phosphorus atom.

[Examples 2, 3] The polyester shown in Table 1 was produced in the same manner as in Example 1 in the proportions shown in Table 1.

[Example 4]

A polyester was produced in the same manner as in Example 1 except that the sodium acetate compound was changed to cobalt acetate.

[Comparative Example 1]

A polyester was produced in the same manner as in Example 1 except that the feed sodium acetate was not added. However, the obtained polyester had a low Tg, and it was confirmed that the pellets agglomerated at a drying temperature of 60 °C.

[Comparative Example 2]

A polyester was produced in the same manner as in Example 1 except that sodium acetate was changed to tributylamine. However, the polycondensation cannot proceed to the target ultimate viscosity, and the color of the resulting resin is also deteriorated.

It is apparent from Table 1 that Examples 1 to 4 can produce a sufficient amount of phosphorus atoms to obtain excellent flame retardancy, and the copolymerization ratio of diethylene glycol is lowered at 11 to 20 mol%. At a lower level, there is a flame retardant polyester having a high degree of polymerization, a high glass transition temperature, and suppressed coloration. On the other hand, in Comparative Example 1, although the acetate was not used, the copolymerization ratio of diethylene glycol was as high as 34 mol% of the obtained flame retardant polyester. Therefore, the glass transition temperature of the obtained polyester becomes low, and agglomeration occurs in the drying step. Further, in Comparative Example 2, when tributylamine was not added without using acetate, the copolymerization ratio of diethylene glycol was suppressed to a low level of 15 mol%, but tributylamine caused partial polymerization. The catalyst is inactivated, and a flame retardant polyester having a high degree of polymerization cannot be produced even if the polymerization time is prolonged. Further, the obtained flame retardant polyester is colored by tributylamine.

[Industrial use possibility]

According to the method for producing a flame retardant polyester of the present invention, a flame retardant polyester which can reduce coloration and is excellent in mechanical properties can be obtained. The flame retardant polyester of the present invention is useful as a flame retardant component blended in a flame retardant masterbatch, and is melt-kneaded by blending the flame retardant masterbatch of the present invention with an arbitrary thermoplastic resin (base resin). It can suppress coloring or mechanical property reduction, and at the same time, a flame retardant thermoplastic resin composition can be obtained. The obtained flame retardant thermoplastic resin composition can be used for fibers for clothing, fibers for industrial materials, films, engineering plastics, and adhesives, etc., by extrusion molding, injection molding, and the like.

Claims (5)

A method for producing a flame retardant polyester, which comprises the steps of heating and mixing a composition containing the following components (A) to (E), and component (A): a phosphorus compound of the following formula (1) (B) component: unsaturated dicarboxylic acid or its ester-forming derivative, (C) component: saturated aliphatic polyol and/or ester-forming derivative mainly composed of ethylene glycol, (D) Component: a polyvalent carboxylic acid other than the component (B) or an ester-forming derivative thereof, and (E) component: a metal acetate. A method for producing a flame retardant polyester comprising the step (P) of heating and mixing a composition containing the following components (A) to (E), and the component (A): the following general formula (1) Phosphorus compound, (B) component: unsaturated dicarboxylic acid or its ester-forming derivative, (C) component: saturated aliphatic polyol and/or ester-forming derivative mainly composed of ethylene glycol, (D) Component: a polyvalent carboxylic acid other than the component (B) or an ester-forming derivative thereof, (E) component: a metal acetate; and a component obtained in the step (P): a component (F): a polymerization catalyst, followed by The step (Q) of heating and depressurizing is performed. The method for producing a flame retardant polyester according to claim 1 or 2, wherein the component (B) is maleic acid, fumaric acid, and/or itaconic acid. A flame retardant masterbatch comprising a flame retardant polyester and a metal acetate salt, and the flame retardant polyester is 200% by mole based on the total of the total polybasic acid component and the total polyol component constituting the flame retardant polyester 20 to 60 mol% of a dicarboxylic acid component having an organic group represented by the following formula (2), a total of 0.05 to 3 mol% of a trivalent or higher polyvalent carboxylic acid component, and/or a trivalent or higher a polyhydric polyol component, 37 to 79.95 mol% of an aromatic dicarboxylic acid component, and a remaining portion of an aliphatic diol component. The Co-b value is -5 to 20, and the Co-L value is 50 or more. The flame-retardant masterbatch of the fourth aspect of the invention, wherein the copolymerization ratio of the diethylene glycol component constituting the flame-retardant polyester resin is 30 mol% or less.