JP2016050227A - Flame-retardant polyester resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flame-retardant polyester resin composition which has high intrinsic viscosity and suppresses generation of a bad smell particularly when the flame-retardant polyester resin composition is prepared or when the flame-retardant polyester resin composition is subjected to molding processing.SOLUTION: The flame-retardant polyester resin composition is obtained by mixing an organic phosphorus-based flame-retardant compound (A) and another compound (B), which contains two or more single bonds between a phosphorus atom and an oxygen atom in one molecule but does not contain a double bond between the phosphorus atom and the oxygen atom, in a polyester resin to obtain a mixture and heating the mixture.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a flame retardant polyester resin composition having a high intrinsic viscosity. More specifically, the present invention relates to the odor during the production of the resin composition and the molding process using the resin composition. The present invention relates to a flame retardant polyester resin composition that is suppressed in generation and has a high intrinsic viscosity.

  Polyester resin products can be manufactured at a low cost and are excellent in heat resistance, electrical insulation, chemical resistance, wear resistance, and the like, and thus are widely used in various fields regardless of industrial households.

  The polyester resin is preferably flame retardant for use in such a wide range of applications. Particularly in the field of electrical and electronic products, due to the recent demand for smaller size and lighter weight, there is a problem of densification of the product and the accompanying increase in heat generation.

  As flame retardant compounds that can impart flame retardancy to polyester resins, halogen-containing compounds such as organic halogen compounds and halogen-containing organic phosphorus compounds are known for their high flame-retardant effects. However, it is regarded as a problem that a resin to which a halogen-containing flame retardant compound is added generates a toxic gas during processing or combustion. In particular, it has been pointed out that bromine-containing flame-retardant compounds generate hydrogen bromide gas during molding and generate dioxin-like gas during combustion. Therefore, in recent years, it has been strongly demanded to use a flame retardant compound containing no halogen.

  As other flame retardant compounds, inorganic compounds typified by magnesium hydroxide, inorganic phosphorus compounds typified by red phosphorus, and organic phosphorus compounds such as phosphate ester compounds, phosphonic acid compounds and phosphinic acid compounds are known. ing. Of these, inorganic flame retardant compounds such as inorganic compounds and inorganic phosphorus compounds are not as toxic as halogen flame retardant compounds, but are poorly compatible with resins and significantly impair the transparency of resins. There is a case. From this point of view, organophosphorus compounds are attracting attention as flame retardant compounds.

  As a technique for making a polyester resin flame-retardant, for example, as disclosed in Patent Documents 1 and 2 and the like, a method of adding or mixing an organic phosphorus compound or copolymer melt extrusion is proposed.

  Among them, a method (copolymerization method) in which a flame-retardant compound is added and copolymerized at the time of polyester polymerization is known as a method having high industrial value because of its bleed-out resistance. For this reason, many methods for copolymerizing an organophosphorus compound with a polyester resin have been proposed for the purpose of imparting flame retardancy. For example, a method of copolymerizing a phosphoric acid ester compound as an organic phosphorus compound with a polyester resin (Patent Document 3), a method of copolymerizing a phosphonic acid compound (Patent Document 4), a phosphorus having a special ester-forming functional group A method of containing a compound (Patent Document 5), a method of copolymerizing carboxyphosphinic acid (Patent Document 6), a method of copolymerizing a phosphine oxide derivative (Patent Document 7), and the like are disclosed.

  However, a copolymer obtained by copolymerizing a phosphorus compound at the time of polyester polymerization has a drawback that the mechanical properties and heat resistance are deteriorated because the melting point is lowered. This is considered to be due to the structure in which a phosphorus compound having a lower softening point intervenes in the molecular chain of the polyester.

  In the case of a phosphate ester compound, it is considered that the binding energy of the PO bond in the compound is small, and the molecular weight is lowered due to the autocatalytic action accompanying the main chain cleavage during the molding process. Such a disadvantage also occurs. That is, if the copolymerization amount of the phosphorus compound in the polyester is increased in order to exhibit higher flame retardancy, the mechanical properties and heat resistance will be deteriorated accordingly. For this reason, it is considered difficult to achieve both flame retardancy, heat resistance, and mechanical properties.

  In view of the above problems, in Patent Document 8, a high melting point is maintained by adding an organophosphorus oligomer having an average molecular weight of a certain level or more as a flame retardant compound without copolymerizing the flame retardant compound. Flame retardant polyester films that have both bleed-out properties and mechanical properties have been proposed.

  However, the flame retardant compound used in the above-mentioned Patent Document 8 has a low IV (Intrinsic Viscosity = intrinsic viscosity) because the compound structural unit is an oligomer. The IV of the polyester resin is also lowered. Since IV has a positive correlation with the molecular weight, a product using a low IV polyester resin is not excellent in durability, tensile properties and the like, and particularly when used in a film, there is a concern about deterioration of film forming stability.

  As a method for solving this problem, a method of reacting with various cross-linking agents is known, and epoxy compounds, carbodiimide compounds, isocyanate compounds and the like are known as effective cross-linking agents for polyester resins. .

  Although these crosslinking agents have a very high IV increase effect, the gas liberated during heat processing gives off a strong odor. Therefore, it is necessary to install a powerful exhaust facility at the place where the crosslinking agent is used. Since the odor generated during the heat processing of the polyester resin is very weak, when the production of a product in which the crosslinking agent is added to the polyester resin is newly started, the capacity of the exhaust facility at the production site may be insufficient. Large-scale capital investment is required.

Japanese Patent Publication No.51-19858 Japanese Patent Publication No. 55-41610 Japanese Patent Publication No.49-22958 JP 59-91122 A Japanese Patent Publication No. 36-20771 Japanese Patent Publication No.53-13479 Japanese Patent Laid-Open No. 1-40521 JP 2012-184399 A

B. H. Bimestre, C.I. Saron; Mater. Res. 2012, 15 (3), 467 M.M. L. Dias, C.I. R. Nascimento; Therm. Anal. Cal. , 2002, 69, 551

  The present invention has been made in view of the above circumstances, and the problem to be solved is a flame-retardant polyester resin composition having a high intrinsic viscosity, and particularly at the time of production of the resin composition or the resin composition. An object of the present invention is to provide a flame-retardant polyester resin composition having a high intrinsic viscosity in which the generation of odor during molding is suppressed.

  As a result of intensive studies in view of the above problems, the present inventors have obtained a flame retardant polyester resin composition having a high IV by forming a film having a specific structure as a cross-linking agent added to a raw material. The present invention has been completed.

  That is, the gist of the present invention includes an organophosphorus flame retardant compound (A), two or more single bonds of phosphorus atom and oxygen atom in the molecule, and a double bond of phosphorus atom and oxygen atom. It exists in the polyester resin composition characterized by heating after mixing a compound (B) which is not in a polyester resin.

  ADVANTAGE OF THE INVENTION According to this invention, the polyester resin composition which achieved high flame retardance can be obtained, without impairing the characteristics, such as heat resistance and durability which polyester resin originally has. When the resin composition is used particularly for the production of a flame-retardant polyester film, the resin composition can contribute not only to increasing the strength of the film but also to improving productivity by stabilizing the film formation, and the industrial value of the present invention is high.

Combustion test equipment

  The polyester resin composition referred to in the present invention refers to, for example, a polyester resin itself or a substance obtained by adding one or more optional components to a polyester resin and mixing them by heating, and these are used as a film or a plate. Also included are those molded into a housing or the like. Although the method for heat mixing is not specifically limited, For example, the method of producing continuously using various extruders, and the method of heating and stirring bulk in a container and mixing are mentioned.

  The polyester resin used in the present invention is not particularly limited, and is mainly a polyester obtained using aromatic dicarboxylic acid or its ester and glycol as main starting materials, and 60% or more of the repeating structural units are present. Polyester having ethylene terephthalate units or ethylene-2,6-naphthalate units. And if it is the conditions which do not deviate from said range, the other 3rd component may be contained. For example, mixing with polyester-type resin, such as a polycarbonate, compatible with resin is mentioned.

  Examples of the aromatic dicarboxylic acid component include, in addition to terephthalic acid and dimethyl terephthalate and 2,6-naphthalenedicarboxylic acid, for example, isophthalic acid, phthalic acid, adipic acid, sebacic acid, oxycarboxylic acid (for example, p-oxyethoxybenzoic acid) Acid, etc.) can be used. In particular, terephthalic acid or dimethyl terephthalate is preferably used.

  As an example of a glycol component, 1 type, or 2 or more types, such as diethylene glycol, propylene glycol, butanediol, 1, 4- cyclohexane dimethanol, neopentyl glycol, can be used other than ethylene glycol, for example. In particular, it is preferable to use ethylene glycol.

  The IV of the flame retardant polyester resin composition of the present invention is usually 0.49 dl / g or more, preferably 0.52 dl / g or more, more preferably 0.54 dl / g or more. When the IV value is less than 0.49 dl / g, there is a case where IV is not increased or decreased even when a crosslinkable compound is added. The crosslinkable compound functions as a mere impurity, and the polyester resin originally has. The heat resistance, mechanical strength, etc., which are the characteristics of the product, may be reduced. Moreover, when used as a film raw material, the film-forming stability may deteriorate. Although the upper limit of IV is not particularly specified, if it is extremely high, an excessive load is applied to the extruder during the molding process, which may cause damage.

  The compound (B) having crosslinkability used in the present invention is a compound that contains two or more single bonds of phosphorus atom and oxygen atom in the molecule and does not contain a double bond of phosphorus atom and oxygen atom. Various phosphite compounds, phosphonite compounds, diphosphinite compounds, ie tris (cyclohexylphenyl) phosphite, methyldiphenylphosphite, bis (2,4-di-tert-butylphenyl) phenylphosphonite, tetrakis (2,4-di-tert-butylphenyl) -4,4-biphenyldiphosphonite, bis (2,4-di-tert-butylphenyl) -diethyl-4,4-biphenyldiphosphinite and the like. . Among them, a phosphite compound described in the following structural formula (1) or (2) is preferable, and particularly “Irgafos126 (manufactured by BASF, molecular weight 605)”, “PEP-36 (manufactured by ADEKA, molecular weight 633)”, "Triphenyl phosphite (molecular weight 310)" is preferred.

In the following structural formulas (1) and (2), R ^{1 to} R ²⁵ are each independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and any of linear, branched, and cyclic The structure may be included. The said compound may be used independently and may use multiple types together.

  These crosslinkable compounds have been reported to cause a crosslinking reaction as shown in the following reaction formula (3) in Non-Patent Document 1 and in the following Reaction Formula (4) in Non-Patent Document 2, but are generally oxidized. Known as stabilizers such as inhibitors. Therefore, not only the IV increase effect as a crosslinking agent, but also the effect as an original stabilizer, that is, by heating at the time of production of the flame-retardant polyester resin composition of the present invention and molding processing using the composition The effect which prevents IV fall can also be expected.

  In the reaction formulas (3) and (4), the substituent represented by “PEster” means a molecular chain of polyester.

  Content of the compound (B) in this invention is defined by the weight ratio with respect to the weight of the whole raw material before mixing. Since the effect of the crosslinking reaction varies depending on the compound (B), the amount of addition cannot be limited unconditionally, but if the amount is too small, the effect of increasing IV may be insufficient and excessive. In such a case, there is a risk of gelation of the resin composition or an extreme increase in the resin extrusion pressure.

  In addition to the state of adding the compound (B) to the raw material system in the present invention, the state of the compound (B) alone, the state of a masterbatch previously kneaded into a polyester resin at a high concentration, and the like can be mentioned. The crosslinkable compound can be added at the stage of polymerizing the polyester resin, but is not particularly limited. However, when the compound (B) is made into a master batch, it is easy to handle as a raw material, but it may be deactivated by causing a reaction in the process of making the master batch. It is desirable to make a masterbatch under conditions that can suppress this reaction.

  In the present invention, an organic phosphorus compound is used as the flame retardant compound. The structure of the organophosphorus flame retardant compound is not particularly limited. For example, carboxymethylphenyl phosphate, (2-carboxyethyl) phenyl phosphate, (2-carboxyethyl) toluyl phosphate, (2-carboxyethyl) 2,5- Dimethylphenyl phosphate, (2-carboxyethyl) cyclohexyl phosphate, (carboxypropyl) phenyl phosphate, (4-carboxyphenyl) phenyl phosphate, (3-carboxyphenyl) phenyl phosphate, (2-carboxyethyl) methyl phosphate, (2- Carboxyethyl) ethyl phosphate, triphenyl phosphate, tributyl phosphate, t-butyl diphenyl phosphate, tris (2-ethylhexyl) phosphate, bisphenol Le A bis (diphenyl phosphate)-1,3-phenyl-bis (diphenyl phosphate), include the compounds described in phosphonitrilic acid diphenyl ester or the following structural formula, (5).

  In the structural formula (5), A is a divalent or trivalent organic residue, and preferred examples thereof include a methylene group, a lower alkylene group such as ethylene, 1,2-propylene, and 1,3-propylene, And bivalent groups such as arylene groups such as 3-phenylene and 1,4-phenylene, 1,3-xylylene, and 1,4-xylylene.

  In Structural Formula (5), Q is a hydrocarbon group having 1 to 18 carbon atoms, and examples thereof include an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, and an allyloxy group. In Structural Formula (5), Z is an ester-forming functional group, specifically, a carboxy group, an alkyl ester having 1 to 6 carbon atoms in the carboxyl group, a cycloalkyl ester, an aryl ester, a hydroxy group, Examples thereof include a hydroxyl alkoxycarbonyl group having 2 to 7 carbon atoms.

  As described above, the structure of the organophosphorus flame-retardant compound used in the present invention is not limited, but it is preferable to use the oligomer described in the following structural formula (6). This organophosphorus compound contains a phosphorus atom in the molecule, and the lower limit of the average molecular weight by GPC measurement is usually 1170, preferably 2290 or more, more preferably 3410 or more. That is, the lower limit value of n in the structural formula (6) is usually 3, preferably 6 or more, more preferably 9 or more. When the average molecular weight is less than 1170, for example, when the film is produced using the polyester resin composition of the present invention, volatilization of the organophosphorus compound and inhibition of crystallization of the polyester resin, and further, Bleed-out may lead to a decrease in the mechanical strength of the film. Moreover, although the upper limit of the average molecular weight of the organophosphorus compound is not particularly defined, dispersibility in the polyester resin may deteriorate if the molecular weight is excessively increased.

  The density | concentration of the phosphorus element contained in the polyester resin composition of this invention is the range of 0.30-2.00 weight% normally, Preferably it is 0.60-1.90 weight%, More preferably, it is 0.90. The range is 1.80% by weight. If the concentration of the elemental phosphorus is less than 0.30% by weight, sufficient flame retardancy may not be obtained. If it exceeds 2.00% by weight, high flame retardancy is obtained, but mechanical strength, etc. The physical properties may be inferior.

  In the present invention, when the flame retardant polyester film is produced, the method for adding the flame retardant compound to the polyester film production system is not particularly limited, but a method of directly adding the flame retardant compound to the polyester resin is preferable. . In addition, there is a method of adding at the time of polyester polymerization. In this case, there is a concern that the polyester and the flame retardant compound are copolymerized and the melting point of the polyester is lowered, resulting in deterioration of mechanical properties and heat resistance.

  In the present invention, it is essential to use a flame retardant compound containing a phosphorus atom together with a crosslinkable compound containing a phosphorus atom. Even if a flame retardant compound is not used, it may be possible to express flame retardancy by adding a large amount of a phosphorus atom-containing crosslinkable compound, but it is crosslinkable enough to achieve the required flame retardant level. When the compound is added, not only the appearance of the product is deteriorated due to gelation of the polyester resin, but also the processing apparatus may be damaged.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded.

(1) Phosphorus concentration measurement The content of phosphorus element in the film was measured using an ICP emission spectrometer (Varian 730-ES). In the measurement, SPST XSTC-22 (phosphorus content: 100 ppm) was used as a standard solution, and calibration curves were prepared from three types of solutions: stock solution, 10-fold dilution (10 ppm) and 100-fold dilution (1 ppm). .

(2) IV measurement A polyester resin composition is precisely weighed to a concentration of 1.0 g · dl ⁻¹ and added to a 1: 1 phenol / tetrachloroethane weight ratio solution. This solution was heated at 110 ° C. for 20 minutes to dissolve the sample, and then the container was immersed in tap water and allowed to cool to room temperature. Using a capillary viscometer “VMS-022UPC • F10” (manufactured by Kosei Co., Ltd.), the flow time of this solution and the flow time of only the phenol / tetrachloroethane solution (reference solution) were measured. From these time ratios, Huggins Was used to calculate the intrinsic viscosity. At that time, the Huggins constant was assumed to be 0.33. The unit of IV is “dl · g ⁻¹ ”.

(3) Presence or absence of odor The presence or absence of odor during the production of the polyester resin composition was confirmed. Although the apparatus used for production is equipped with an appropriate exhaust system, it is desirable from the viewpoint of employee health management that no odor is generated or that it can be made as weak as possible.

(4) Presence or absence of gelation It evaluated from the presence or absence of the unevenness | corrugation of the resin melt surface extruded from an extruder. A product using a gelled resin loses the smoothness of the surface and the appearance is impaired. Therefore, it is necessary to examine the conditions under which the resin does not gel.

(5) Flame retardance UL94VTM test is performed in accordance with UL94, a flammability test standard for plastic materials issued by Underwriters Laboratories (UL). Since the results of this test method often vary, for the purpose of further improving the reliability of the evaluation, it was decided that the test was usually performed 10 times for each type of polyester film sample 10 times. Below, a flame-retardant evaluation procedure is demonstrated.

(I) Preparation of test piece The film is cut into 200 mm × 50 mm, and a marked line is put in the width direction of the sample at 125 mm from the bottom of the sample. The vertical axis of the sample is tightly wound around the vertical axis of a rod having a diameter of 12.7 mm to form a cylindrical shape with a length of 200 mm, in which a 125 mm line is exposed to the outside. The edge protruding outside the sample is fixed with adhesive tape between 75 mm above the 125 mm mark (upper part of the cylinder). Finally pull out the stick.

(Ii) Conditioning The test piece obtained in (i) above was treated for 48 hours or more in an environment of (a) temperature 23 ± 2 ° C. and relative humidity 50 ± 5%. (B) 168 ± at temperature 70 ° C. ± 2 ° C. After the treatment for 2 hours, prepare 10 pieces each cooled for 4 hours or more at an air temperature of 23 ± 2 ° C. and a relative humidity of 20% or less. (A) is called an acceptance state, and (b) is called an aging state.

(Iii) Fixing the test piece The vertical axis of the test piece of (ii) is fixed with a clamp with a spring at a position of 6 mm in the length of the upper end, and the upper end of the cylinder is closed to provide a chimney effect during the test. Prevent it from occurring. Immediately under the test piece, a piece of 0.05 g absorbent cotton (50 mm × 50 mm) having a maximum thickness of 6 mm is placed horizontally, and the lower end of the test piece is 300 mm above the absorbent cotton (FIG. 1). reference).

(Iv) Burner adjustment Adjust so that a blue flame with a height of 20 mm comes out from the burner. In order to emit the flame, the gas supply and the air inlet of the burner are adjusted so that a blue flame with a yellow tip and a height of 20 mm comes out. Then increase the air supply until the yellow tip disappears. Then measure the flame height again and readjust as necessary. At this time, the methane gas supply to the burner is adjusted in flow rate by a method according to “ASTM D 5207”.

(V) First flame contact The flame is applied to the center point of the lower end of the test piece that is not wound, and the tip of the burner is 10 ± 1 mm below the center point. Continue flame contact for 3 seconds. However, since the length and center position of the test piece change due to combustion, the position of the burner is moved according to the change. If melt or fumes are dripping during flame contact, tilt the burner angle up to 45 degrees and just enough of the specimen to prevent them from falling into the burner tube. Move from below. Meanwhile, a distance of 10 ± 1 mm must be maintained between the center of the tip of the burner and the remaining portion of the test piece. Immediately after 3 seconds of indirect flame, the burner is moved away from the test piece at a rate of about 300 mm per second by at least 150 mm, and at the same time, the afterflame time t ₁ is started to be measured in seconds by the aging device.

(Vi) Second flame contact When the after flame of the test piece resulting from the first flame contact disappears (even if the burner is not further away from the test piece to more than 150 mm), immediately remove the burner to the test piece. The burner is held at a location 10 mm ± 1 mm away from the lower end of the remaining part of the test piece. However, if necessary, the burner is moved so that the behavior of falling objects due to combustion can be confirmed without any obstructions. Immediately after the 3 second indirect flame, the burner is moved away from the test piece at a rate of about 300 mm per second by at least 150 mm, and at the same time, the afterflame time t ₂ is started to be measured in seconds by the aging device.

(Vii) Flame Retardancy Evaluation Criteria Flame retardance was evaluated based on the UL94 standard. The evaluation criteria are as shown in Table 1 below, which means that VTM-0 has the most excellent flame retardancy, and the order is "VTM-1>VTM-2>fail". In the present invention, the term “flame retardant polyester resin composition” is defined as having flame retardancy equivalent to VTM-0 when processed into a film having a thickness of 50 μm.

  The manufacturing method of the raw material used in the Example and the comparative example is as follows. However, these are merely examples for explaining the present invention, and do not limit the raw materials that can be used in the present invention.

≪Production of flame retardant compounds≫
9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (the following structural formula (7) was added to a 3 L glass flask equipped with a stirrer, thermometer, gas inlet, and distillation port. )) 7.8 mol and 25.97 mol of ethylene glycol were added and the flask was heated until the temperature of the contents reached 100 ° C. to dissolve the components. Next, 7.96 mol of itaconic acid was added with stirring, and the flask was heated from the distillation port through a vacuum device in a vacuum state of 30 Torr to bring the contents to a boil. At this point, the produced water was removed by adjusting the distillation rate of the distillation port. Furthermore, while maintaining the boiling state of the contents, the temperature in the flask was raised, and the degree of vacuum was also lowered accordingly. As a breakdown, it took 4 hours for the temperature of the contents to reach 185 ° C., and the degree of vacuum at this point was 430 Torr. Further, the heating was continued, and finally the contents were heated until the temperature reached 200 ° C. After confirming this point, nitrogen gas was blown into the reactor to return the flask to normal pressure. The reaction mixture is an ethylene glycol solution of the following structural formula (8). Moreover, a solid compound of the following structural formula (8) can be purified by removing ethylene glycol under reduced pressure.

Subsequently, 130 g of ethylene glycol containing 0.33 g of antimony trioxide (Sb ₂ O ₃ ) and zinc acetate dihydrate [(AcO) ₂ Zn · 2H ₂ O] was added into the flask. The inside of the flask was maintained at 200 ° C., and the degree of vacuum was gradually increased to obtain a vacuum state of 1 Torr or less. Furthermore, the temperature of the content was raised to 220 ° C., and the point at which the distillation of ethylene glycol was extremely reduced was determined as the reaction end point. After confirming this point, the content is solidified in a SUS container while pressurizing with nitrogen gas, so that it is a yellowish transparent glassy solid, a flame-retardant organic phosphorus compound, that is, the following structural formula (9 2- (9,10-dihydro-9-oxa-10-oxide-10-phosphaphenanthrene-10-yl) methylsuccinic acid bis- (2-hydroxyethyl) Obtained.

  By repeating the above operation, 2- (9,10-dihydro-9-oxa-10-oxide-10-phosphaphenanthrene-10-yl) methyl succinic acid bis- (2) added in Examples and Comparative Examples described later is used. The required amount of deethylene glycol polycondensate of (hydroxyethyl) was ensured.

  Regarding this flame-retardant organophosphorus compound, the weight average molecular weight (Mw) was 6,800 from GPC analysis of the product. In this analysis, a peak in a low molecular weight region, which is estimated to be an acid anhydride of a compound represented by the following structural formula (10) or a cyclic ester of a compound represented by the structural formula (10) and ethylene glycol, is also present. Observed. Further, XRF measurement showed that the phosphorus content was 8.31 wt%. Therefore, the average value of n of the flame retardant organophosphorus compound was equivalent to 18.1. The flame retardant organophosphorus compound is hereinafter referred to as FR1.

≪Manufacture of polyester A≫
100 parts by weight of dimethyl terephthalate and 60 parts by weight of ethylene glycol are used as starting materials, 0.02 part by weight of magnesium acetate tetrahydrate as a catalyst is taken in the reactor, the reaction start temperature is set to 150 ° C., and the methanol is gradually distilled off. The reaction temperature was raised to 230 ° C. after 3 hours. After 4 hours, the transesterification reaction was terminated. After adding 0.03 part by weight of ethyl acid phosphate to this reaction mixture, it was transferred to a polycondensation tank, 0.04 part by weight of antimony trioxide was added, and a polycondensation reaction was carried out for 4 hours. That is, the temperature was gradually raised from 230 ° C. to 280 ° C. On the other hand, the pressure was gradually reduced from normal pressure, and finally 0.3 mmHg. After the start of the reaction, the reaction is stopped at a time corresponding to IV = 0.66 due to a change in the stirring power of the reaction tank, the polymer is discharged under nitrogen pressure, pulled out into a strand, cooled with water, and then cut with a cutter. Polyester resin pellets (prepolymer) were produced. Using this prepolymer as a starting material, solid phase polymerization was performed at 220 ° C. under vacuum to obtain polyester A in a pellet state. The obtained polyester had an IV of 0.85.

≪Manufacture of polyester B≫
Polyester A and FR1 were compounded in a twin screw extruder with a vent at a ratio of 65:35 to obtain polyester B which is a flame retardant compound MB. The obtained polyester had an IV of 0.46.

<< Manufacture of cross-linking agent a >>
Under room temperature and a nitrogen stream, 200.5 mmol of pentaerythritol, 9.9 mmol of pyridine, and 80 ml of toluene were placed in a three-necked flask, and 417.6 mmol of phosphorus trichloride was added dropwise over 20 minutes while stirring, followed by stirring for 1 hour. Thereafter, the mixture was heated to 80 ° C., further stirred for 1 hour, and then cooled to room temperature. The generated hydrogen chloride was absorbed into an aqueous sodium hydroxide solution outside the reaction system through a reflux condenser.

To the resulting white suspension, 80 ml of toluene and 425.4 mmol of pyridine were added, and a solution of 408.4 mmol of 2,6-di-tert-butyl-p-cresol and 110 ml of toluene was added dropwise over 50 minutes under a nitrogen stream. And stirred for 30 minutes.
Subsequently, the obtained white suspension was filtered with a glass filter under a nitrogen stream, and the white solid remaining on the filter was washed with toluene to obtain a filtrate. Further, the filtrate was washed once with 400 ml of 0.5N aqueous sodium hydroxide solution and twice with 400 ml of pure water under a nitrogen atmosphere, filtered through a glass filter, and the resulting white solid was vacuum-dried at 60 ° C. As a result, a white powdery crosslinking agent a was obtained. ^{From 31} P NMR measurement, it was found that the crosslinking agent a had a structure as shown in the following structural formula (11). By repeating the above operation, a necessary amount of the crosslinking agent a was secured.

<< Manufacture of cross-linking agent b >>
6.42 mol of phenol and 2.01 mol of phosphorus trichloride were placed in a four-necked flask and stirred at 40 to 50 ° C. for 1 hour at atmospheric pressure under a nitrogen stream. The obtained solution was washed once with 400 ml of 0.5N aqueous sodium hydroxide solution and twice with 400 ml of pure water under a nitrogen atmosphere, filtered through a glass filter, and the resulting white solid was vacuumed at 60 ° C. It dried and the white powder-like crosslinking agent b was obtained. ^{From 31} P NMR measurement, it was found that the crosslinking agent b had a structure represented by the following structural formula (12). By repeating the above operation, a necessary amount of the crosslinking agent b was secured.

Examples 1-4:
Various raw materials mixed at the ratios shown in Table 2 above were fed into an extruder set at 270 ° C. Here, a twin screw extruder in the same direction was used as the extruder. Extruder polymer is extruded into a sheet form from the die through a gear pump and a filter, and rapidly cooled and solidified using an electrostatic cooling method with a rotating cooling drum whose surface temperature is set to 30 ° C. Got the sheet. The obtained amorphous sheet was stretched 3.0 times in the longitudinal direction at 85 ° C., then stretched 3.0 times in the transverse direction at 125 ° C. and heat-treated at 215 ° C., and a biaxially stretched polyester film having a thickness of 50 μm Got. In any formulation, the IV was good, and there was no odor or gelation during extrusion, and it was found that the flame retardancy was as high as VTM-0. Table 2 below shows the raw material composition and evaluation results of each example.

Comparative Example 1:
By processing the raw materials mixed in the composition shown in Table 3 below in the same manner as in Example 1, a biaxially stretched polyester film having a thickness of 50 μm was obtained. The value of IV was sufficient, but the flame retardancy was less than VTM-0.

Comparative Example 2:
By processing the raw materials mixed in the formulation shown in Table 3 in the same manner as in Example 1, a biaxially stretched polyester film having a thickness of 50 μm was obtained. Although the flame retardancy was sufficient, the IV was low, and there was a concern that the molded body was insufficient in strength.

Comparative Examples 3-5:
Biaxially stretched polyester films having a thickness of 50 μm were obtained by processing the raw materials mixed in the formulations described in Table 3 in the same manner as in Example 1. Both flame retardancy and IV were good, but a strong odor was generated during extrusion.

Comparative Example 6:
Although the raw material mixed by the mixing | blending of the comparative example 6 of Table 3 was injected | thrown-in to the extruder similarly to Example 1, the extruded resin raise | generated gelation intensely. Therefore, since it was difficult to form into a film, the flame retardancy could not be evaluated.

  In the above table, cross-linking agent c is “Joncry ADR-4368” manufactured by BASF, Mw = 6,800, epoxy equivalent = 285 g / mol, and cross-linking agent d is “Stabaxol P400” manufactured by Rhein Chemie, Mw> 20,000. The carbodiimide equivalent is> 13.5 wt%, and the crosslinking agent e is “Carbodilite HMV-8CA” manufactured by Nisshinbo Chemical Co., Ltd. Mw = 3,000, carbodiimide equivalent = 330 g / mol.

According to the present invention, it is possible to obtain a polyester resin composition imparted with flame retardancy without impairing the appearance and mechanical strength inherent to the polyester resin, and to suppress the generation of odor during production. . The industrial value of the present invention is high.

1 Clamp 2 Tape 3 125mm Mark 4 Burner 5 Cotton

Claims (2)

An organophosphorus flame retardant compound (A), and a compound (B) containing two or more single bonds of phosphorus atom and oxygen atom in the molecule and not containing a double bond of phosphorus atom and oxygen atom, A polyester resin composition obtained by mixing in a polyester resin and heating. The polyester resin composition according to claim 1, wherein the flame retardant compound (B) is a compound represented by the following structural formula (1) or (2).
(In the above structural formulas (1) and (2), R ^{1 to} R ²⁵ are each independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and any structure of linear, branched, and cyclic structures. And may contain double or triple bonds)