JP2007138019A - Flame-retardant polybutylene terephthalate resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flame-retardant polybutylene terephthalate resin composition which is excellent in flame retardancy and simultaneously exhibits effects excellent in anti-creep characteristics and a gas production-inhibiting property. <P>SOLUTION: This polybutylene terephthalate resin composition comprises, based on the (A) 100 pts.wt. of polybutylene terephthalate resin, (B) 3 to 50 pts.wt. of a brominated polycarbonate, (C) 1 to 30 pts.wt. of an antimony oxide compound, and (D) 0 to 150 pts.wt. of a reinforcing filler, wherein (A) the polybutylene terephthalate resin contains (a) a titanium compound and (b) a group 1 metal compound and/or a group 2 metal compound; the content of (a) the titanium compound is 10 to 80 ppm converted into titanium atom; and the total content of (b) the group 1 metal compound and/or the group 2 metal compound is 1 to 50 ppm converted into the metals. A resin molded article using the same. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a flame retardant polybutylene terephthalate resin composition that retains excellent flame retardancy, is excellent in creep rupture properties, and further suppresses gas generation during heating and the like.

  Polybutylene terephthalate resin (sometimes abbreviated as PBT), which is a representative engineering plastic among thermoplastic polyester resins, is easy to mold, mechanical properties, heat resistance, and other physical and chemical properties. It is widely used in fields such as automobile parts, electrical / electronic parts, precision equipment parts.

  Flame resistance is required for resins used for electrical, electronic parts, automobile parts, other electrical parts, machine parts, and the like. In recent years, electrical and electronic parts and electrical parts have been made thinner and smaller due to the trend of miniaturization and weight reduction of various devices, and various molded products used therefor have been made smaller and thinner. In thin-walled molded products, flame retardancy corresponding to the thinnest part is often required, and as flame retardancy, the flame retardancy of rank V-0 defined in UL-94 is used as an index. The thinner the molded product, the more difficult it becomes to achieve flame retardancy. In order to achieve a predetermined flame retardancy in response to such demands, a large amount of flame retardant is often contained in PBT, whereas PBT containing a large amount of flame retardant is resistant to hydrolysis and resistance. There has been a problem that a reduction in heat shock is likely to be caused.

  In contrast, for example, addition of brominated polycarbonate as a flame retardant for PBT has been proposed (see, for example, Patent Document 1). This is because the compatibility between the brominated polycarbonate and PBT is good, and therefore excellent flame retardancy and maintenance of the strength of the resin composition are expected.

  Further, when PBT is used for electrical and electronic parts such as relay parts, organic gas generated from PBT at a high temperature has also been a problem. This is because there is a concern that this gas may cause corrosion of metal contacts in the electric and electronic parts and adhesion of carbides to the contacts, resulting in poor conduction. Has been proposed (see, for example, Patent Document 2).

JP-A-11-269364 JP 2004-91583 A

  However, in the method described in Patent Document 1, there are problems such as yellowing of the resin composition and melt heat stability caused by transesterification between PBT and brominated polycarbonate. Ester and phosphoric acid and phosphorous acid metal salts have been blended, but such additives are not always desirable as a countermeasure against metal contact corrosion described later, and are not a sufficient solution.

Especially for PBT resin parts such as relay parts that are used in close-to-sealing environments, the temperature of the operating environment rises due to sparks at the time of opening and closing the contacts. Under these circumstances, the maintenance of strength is required even under a high temperature environment. In other words, electrical and electronic parts such as relay parts are simultaneously required to have a high degree of flame retardancy due to thinning, prevention of contact corrosion due to the generation of organic gas, and excellent creep resistance at high temperatures. However, the improved methods that have been proposed so far have not yet been fully resolved.

  An object of the present invention is a relay that simultaneously satisfies all of flame retardancy, creep resistance, and further suppression of gas generation at high temperatures, etc., without containing a large amount of various additives other than flame retardants and reinforcing agents. Another object of the present invention is to provide a flame retardant polybutylene terephthalate resin composition that can be suitably used for electric and electronic parts such as connector parts.

The present inventors have started studies to solve the above problems. Then, paying attention to the metal compound contained in PBT, intensive studies were conducted on the type and content thereof and the relationship with other additives other than PBT.
As a result, as PBT, a PBT containing a specific amount of a titanium compound and a group 1 or group 2 metal compound, in particular, using these metal compounds as a polymerization catalyst for PBT, the content of these metal compounds was set to a specific amount. A PBT composition containing a specific amount of a specific flame retardant and a flame retardant aid using PBT not only exhibits good flame retardancy, but is also excellent in creep resistance and gas generation suppression. It was found that there was an effect.

  The resin molded product obtained using this PBT composition is also found to be a resin molded component excellent in various characteristics as described above, particularly a relay resin component in which the inside is close to a sealed atmosphere. The present invention has been completed.

  That is, the gist of the present invention is that (A) 3 to 50 parts by weight of a brominated polycarbonate, (C) 1 to 30 parts by weight of an antimony oxide compound, and (D) with respect to 100 parts by weight of the polybutylene terephthalate resin. 0 to 150 parts by weight of reinforcing filler, (A) the polybutylene terephthalate resin contains (a) a titanium compound, (b) a Group 1 metal compound and / or a Group 2 metal compound, and (a) a titanium compound The polybutylene terephthalate has a content of 10 ppm or more and 80 ppm or less in terms of titanium atom, and (b) the content of the Group 1 metal compound and / or the Group 2 metal compound is 1 ppm or more and 50 ppm or less in terms of the metal atom. The present invention resides in a resin composition and a resin molded product formed by molding the resin composition.

  The PBT resin composition of the present invention is excellent in flame retardancy and at the same time has excellent effects in creep resistance and gas generation suppression. Therefore, it can be suitably used for electrical / electronic parts such as relay parts. Further, since the composition of the present invention has a simple composition, it is advantageous from the viewpoint of cost and can be expected to contribute to the stability of quality.

Hereinafter, the present invention will be described in detail.
(A) Polybutylene terephthalate resin (A) Polybutylene terephthalate resin (PBT) used in the present invention has a structure in which a terephthalic acid unit and a 1,4-butanediol unit are ester-bonded, and 50 mol of a dicarboxylic acid unit. % Refers to a polymer composed of terephthalic acid units and 50 mol% or more of the diol component composed of 1,4-butanediol units.

If the terephthalic acid unit or the 1,4-butanediol unit is too low, for example, if it is less than 50 mol%, the crystallization rate of PBT may decrease, and the moldability of the resulting polybutylene terephthalate resin may decrease. Therefore, the proportion of terephthalic acid units in all dicarboxylic acid units is usually 70 mol% or more, preferably 80 mol% or more, more preferably 95 mol% or more, and particularly preferably 98% or more. The proportion of 1,4 butanediol units is usually 70 mol% or more, preferably 80 mol% or more, more preferably 95 mol% or more, and particularly preferably 98% or more.

In the dicarboxylic acid component which is a raw material of (A) PBT used in the present invention, there is no particular limitation on the dicarboxylic acid component other than terephthalic acid. Specifically, for example, phthalic acid, isophthalic acid, 4,4′-diphenyldicarboxylic acid, 4,4′-diphenyl ether dicarboxylic acid, 4,4′-benzophenone dicarboxylic acid, 4,4′-diphenoxyethanedicarboxylic acid, Aromatic dicarboxylic acids such as 4,4′-diphenylsulfone dicarboxylic acid and 2,6-naphthalenedicarboxylic acid; fats such as 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid Cyclic dicarboxylic acids; aliphatic dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid and sebacic acid;
These dicarboxylic acid components can be introduced into the polymer skeleton as a dicarboxylic acid or using a dicarboxylic acid derivative such as a dicarboxylic acid ester or a dicarboxylic acid halide as a raw material.

Moreover, in the diol component which is a raw material of (A) PBT used for this invention, there is no restriction | limiting in particular as diol components other than 1, 4- butanediol. Specifically, for example, ethylene glycol, diethylene glycol, polyethylene glycol, 1,2-propanediol, 1,3-propanediol, polypropylene glycol, polytetramethylene glycol, dibutylene glycol, 1,5-pentanediol, neopentyl glycol Aliphatic diols such as 1,6-hexanediol and 1,8-octanediol; 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethylol, 1,4-cyclohexanedimethylol Alicyclic diols such as xylylene glycol, 4,4′-dihydroxybiphenyl, 2,2-bis (4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, and the like; Cited The

  Further, (A) PBT used in the present invention includes lactic acid, glycolic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, 6-hydroxy-2-naphthalenecarboxylic acid, p-β-hydroxyethoxybenzoic acid and the like. Hydroxycarboxylic acids; monofunctional components such as alkoxycarboxylic acid, stearyl alcohol, benzyl alcohol, stearic acid, benzoic acid, t-butylbenzoic acid, benzoylbenzoic acid; tricarbaric acid, trimellitic acid, trimesic acid, pyromellitic acid, A copolymer obtained by copolymerizing trifunctional or more polyfunctional components such as gallic acid, trimethylolethane, trimethylolpropane, glycerol, pentaerythritol, and the like can also be used.

  (A) PBT used in the present invention contains (a) a titanium compound and (b) a Group 1 metal compound and / or a Group 2 metal compound, and (a) the content of the titanium compound is in terms of titanium atoms. 10 ppm to 80 ppm, and (b) the content of the Group 1 metal compound and / or the Group 2 metal compound is 1 ppm to 50 ppm in terms of metal atoms.

  (A) PBT used in the present invention is a polycondensation of an oligomer obtained by an esterification reaction (or transesterification reaction) between 1,4-butanediol and terephthalic acid (or dialkyl terephthalate). By using (a) a titanium compound and (b) a group 1 metal compound and / or a group 2 metal compound as a catalyst (polycondensation catalyst) used in the polycondensation, (A) (a ) And (b) are preferable because the dispersibility of the metal compound can be improved.

These polycondensation catalysts can be used at any time. Specifically, examples of the usage method include the following methods (1) to (4). Hereinafter, (a) a titanium compound may be referred to as a titanium catalyst, and (b) a group 1 metal compound and a group 2 metal compound may be referred to as a group 1 metal catalyst and a group 2 metal catalyst, respectively.
(1) A method of using both (a) and (b) in the esterification reaction (or transesterification reaction) and bringing them into the polycondensation reaction.
(2) A method in which (a) and (b) are partially used in the esterification reaction (or transesterification reaction) and added at the start of the polycondensation reaction or during the reaction.
(3) A method in which one of the catalysts (a) and (b) is used in the esterification reaction (or transesterification reaction), and the other is added at the start of the polycondensation reaction or during the reaction.
(4) A method in which neither (a) nor (b) is used in the esterification reaction (or transesterification reaction), and both are added at the start of the polycondensation reaction.

  The (a) titanium compound used in the present invention is not particularly limited. Specifically, for example, inorganic titanium compounds such as titanium oxide and titanium tetrachloride; titanium alcoholates such as tetramethyl titanate, tetraisopropyl titanate and tetrabutyl titanate And the like; and titanium phenolates such as tetraphenyl titanate; Of these, titanium alcoholates are preferable, tetraalkyl titanates are more preferable, and tetrabutyl titanate is particularly preferable.

  The (b) Group 1 metal compound and / or Group 2 metal compound used in the present invention is not particularly limited. Specifically, for example, the Group 1 metal compound may be hydroxylated with lithium, sodium, potassium, rubidium, or cesium. Compounds; oxides; alcoholates; various organic acid salts such as acetates, phosphates, carbonates, etc., and examples of group 2 metal compounds include beryllium, magnesium, calcium, strontium, Various compounds such as barium hydroxides; oxides; alcoholates; various organic acid salts such as acetates, phosphates and carbonates; These may be used alone or in combination.

  Among them, lithium, sodium, potassium, magnesium, calcium, and other compounds are preferable from the viewpoints of handling and availability, and catalytic effect, and lithium or magnesium compounds that are excellent in catalytic effect and color tone are preferable, especially magnesium compounds. Is preferred. Specific examples of the magnesium compound include magnesium acetate, magnesium hydroxide, magnesium carbonate, magnesium oxide, magnesium alkoxide, and magnesium hydrogen phosphate. Of these, organic acid salts are preferable, and magnesium acetate is particularly preferable.

The content of (a) titanium compound in (A) PBT used in the present invention is 10 ppm or more and 80 ppm or less in terms of titanium atom. When there is too much content of this titanium compound, the color tone and hydrolysis resistance of (A) PBT may fall, and the solution haze and foreign material by deactivation of a titanium catalyst may increase. On the other hand, if the amount is too small, (A) the polymerizability of PBT is lowered. Therefore, the content of the (a) titanium compound is preferably 70 ppm or less, particularly 60 ppm or less, more preferably 50 ppm or less, and particularly preferably 40 ppm or less, and the lower limit thereof is 15 ppm or more, especially 20 ppm or more, and particularly preferably 30 ppm or more. .

  In (A) PBT used in the present invention, the content of (b) Group 1 metal compound and / or Group 2 metal compound is 1 ppm or more and 50 ppm or less in terms of each metal atom. When there is too much content of this group 1 metal compound and / or a group 2 metal compound, the moldability of the PBT composition of this invention and the hydrolysis resistance of the resin molded product obtained may fall. On the other hand, if the amount is too small, the heat shock resistance may decrease. Therefore, the content of (b) Group 1 metal compound and / or Group 2 metal compound is 40 ppm or less, preferably 30 ppm or less, more preferably 20 ppm or less, particularly preferably 15 ppm or less, and the lower limit thereof is 3 ppm or more, especially 5 ppm or more. In particular, it is preferably 10 ppm or more.

  The metal content such as titanium atom can be measured using a method such as atomic emission, atomic absorption, Inductively Coupled Plasma (ICP) after recovering the metal in the polymer by a method such as wet ashing.

  Examples of the polycondensation catalyst for (A) PBT used in the present invention include the titanium compounds as described above and (b) Group 1 metal compounds and / or Group 2 metal compounds. Examples of other polycondensation catalysts include: Tin and its compound are mentioned. Tin is usually used as a tin compound, specifically, for example, dibutyltin oxide, methylphenyltin oxide, tetraethyltin, hexaethylditin oxide, cyclohexahexylditin oxide, didodecyltin oxide, triethyltin hydroxide, Triphenyltin hydroxide, triisobutyltin acetate, dibutyltin diacetate, diphenyltin dilaurate, monobutyltin trichloride, tributyltin chloride, dibutyltin sulfide, butylhydroxytin oxide, methylstannic acid, ethylstannic acid, butylstannic acid, etc. Can be mentioned.

However, since tin and tin compounds generally deteriorate the color tone of (A) PBT, the content of tin compound in (A) PBT used in the present invention is preferably low and preferably not contained. Specifically, it is preferable that the content of the tin compound is usually 200 ppm or less, particularly 100 ppm or less, more preferably 10 ppm or less in terms of tin atoms.

  In the production of (A) PBT used in the present invention, in addition to the titanium catalyst, group 1 metal catalyst and group 2 metal catalyst, antimony compounds such as antimony trioxide; germanium such as germanium dioxide and germanium tetroxide. Reaction aids such as compounds; manganese compounds; zinc compounds; zirconium compounds; cobalt compounds; phosphorous compounds such as orthophosphoric acid, phosphorous acid, hypophosphorous acid, polyphosphoric acid, and their esters and metal salts;

  Although the terminal carboxyl group concentration of (A) PBT used in the present invention is arbitrary, it is preferably lower, specifically 30 μeq / g or less, more preferably 5 to 25 μeq / g, particularly preferably 5 to 5 μeq / g. 20 μeq / g. If it exceeds 30 μeq / g, hydrolysis resistance and residence heat stability tend to deteriorate, and if it is too low, heat shock resistance deteriorates.

  Next, the manufacturing method of (A) PBT used for this invention is demonstrated. The method for producing (A) PBT used in the present invention is arbitrary. Generally, depending on the raw materials used, a method using a dicarboxylic acid as a main raw material (direct polymerization method) and a method using a dicarboxylic acid dialkyl ester as a main raw material (Transesterification method). The former has a difference in that water is mainly produced in the initial esterification reaction, and the latter mainly produces alcohol in the initial transesterification reaction.

  In addition, the (A) PBT production method used in the present invention is generally divided into batches according to the raw material supply or the form of extraction of the polybutylene terephthalate resin as the produced polymer (method of extracting the produced (molten) polymer from a reaction vessel or the like) The law is broadly divided into law and continuous law. The initial esterification reaction or transesterification reaction is performed in a continuous operation, and the subsequent polycondensation is performed in a batch operation, or the initial esterification reaction or transesterification reaction is performed in a batch operation, and the subsequent polycondensation is performed in a continuous operation. The method of performing is known.

  As the method for producing (A) PBT used in the present invention, it is preferable to use a direct polymerization method from the viewpoint of the superiority of the raw material basic unit, the ease of processing of by-products, and the quality of the obtained (A) PBT. It is preferable to use a so-called continuous method in which an esterification reaction and a polycondensation reaction are continuously performed in terms of stability and energy efficiency in production.

The aforementioned Group 1 metal catalyst and / or 2 used in the production of (A) PBT used in the present invention
The group metal catalyst can be supplied to the esterification reaction tank or the transesterification reaction tank, but the supply position is not particularly limited, and may be supplied from the reaction gas phase portion of the reaction tank to the upper surface of the reaction liquid. Alternatively, it may be supplied directly to the reaction liquid phase part. Moreover, in this case, it may be supplied together with the raw material terephthalic acid or the titanium catalyst, or may be supplied independently. Among these, from the viewpoint of the stability of the catalyst, it is preferable to supply the terephthalic acid and the titanium catalyst independently from the terephthalic acid and the titanium catalyst and to the upper surface of the reaction solution from the reaction solution gas phase part.

  As a method for supplying the group 2 metal catalyst, for example, when the group 2 catalyst is solid at room temperature, it can be supplied to the reaction solution as a solid, but the supply amount is stabilized, and adverse effects such as heat denaturation are caused. In order to reduce, it is preferable to dissolve in a solvent such as water or 1,4-butanediol and supply as a solution. The concentration of the Group 2 metal catalyst in this solution is usually 0.01% by weight or more, preferably 0.05% by weight or more, and particularly preferably 0.08% by weight or more, and the upper limit is 20% by weight or less. It is preferably 10% by weight or less, particularly preferably 8% by weight or less.

  Moreover, you may add a group 1 metal catalyst and / or a group 2 metal catalyst to the polycondensation reaction tank following an esterification reaction tank or a transesterification reaction tank, and the oligomer piping attached to it. In this case, the addition method also stabilizes the supply amount and reduces adverse effects such as heat denaturation, such as water, a solvent such as 1,4-butanediol, and a copolymer component such as polytetramethylene ether glycol. It is preferable to melt | dissolve and supply as a solution, and the density | concentration in this case is the same as the above-mentioned solution density | concentration.

  As a specific example of the method for producing (A) PBT used in the present invention, for example, in the case of a continuous esterification method using a direct polymerization method, the following method may be used. A dicarboxylic acid component mainly composed of terephthalic acid, which is a raw material, and a diol component mainly composed of 1,4-butanediol are mixed in a raw material mixing tank to form a slurry, and in one or a plurality of esterification reaction tanks In the presence of a titanium catalyst and a Group 1 metal catalyst and / or a Group 2 metal catalyst, the temperature condition is usually 180 to 260 ° C, preferably 200 to 245 ° C, more preferably 210 to 235 ° C. The pressure (indicating absolute pressure; hereinafter the same) conditions are usually 10 to 133 kPa, preferably 13 to 101 kPa, more preferably 60 to 90 kPa, and usually 0.5 to 10 hours. Preferably, the esterification reaction is continuously performed for 1 to 6 hours.

  Any conventionally known esterification reaction tank or transesterification reaction tank can be used. Specifically, for example, a vertical stirring complete mixing tank, a vertical heat convection mixing tank, a tower-type continuous reaction tank, and the like can be mentioned. These may be used as a single tank or as a plurality of reaction tanks in which the same or different reaction tanks are connected in series or in parallel. Among them, it is preferable to use a reaction tank having a stirring device. As the stirring device, in addition to a normal stirring device including a power unit, a bearing, a shaft, a stirring blade, etc., a turbine stator type high-speed rotary stirrer, a disc mill type stirrer Alternatively, a rotor mill type stirrer or the like capable of high speed rotation may be used.

  Next, the obtained oligomer as the esterification reaction product (or transesterification reaction product) is transferred to a polycondensation reaction tank. Although the esterification rate of this oligomer is arbitrary, it is usually 90% or more, preferably 95% or more, and the number average molecular weight is usually 300 to 3000, preferably 500 to 1500.

  The form of the polycondensation reaction tank is arbitrary, and examples thereof include a vertical stirring complete mixing tank, a vertical heat convection mixing tank, a tower-type continuous reaction tank, and the like, and these may be used in combination. Among these, at least one polycondensation reaction tank preferably has a stirrer, and the stirrer is the same as the esterification reaction layer described above.

  The form of stirring is not particularly limited, and in addition to the usual stirring method in which the reaction solution in the reaction tank is directly stirred from the top, bottom, side, etc. of the reaction tank, a part of the reaction solution is connected to the reactor by piping or the like. A method of circulating the reaction liquid by taking it outside and stirring it with a line mixer or the like may be used. Further, a horizontal reactor having a rotating shaft in the horizontal direction and excellent in self-cleaning may be used. .

  The polycondensation reaction is performed in the presence of a titanium catalyst and a group 1 metal catalyst and / or a group 2 metal catalyst. The reaction temperature is usually 210 to 280 ° C, preferably 220 to 250 ° C, particularly preferably 230 to 245 ° C. For example, when using several reaction tanks, it is preferable that the temperature of the at least 1 reaction tank is 230-240 degreeC. The reaction is preferably performed under stirring conditions. The polycondensation reaction time is usually 1 to 12 hours, preferably 3 to 10 hours. The pressure condition of the reaction atmosphere is usually 27 kPa or less, preferably 20 kPa or less, particularly preferably 13 kPa or less. For example, when a plurality of reaction vessels are used, the pressure in at least one of the reaction vessels is usually 1.3 kPa or less, particularly 0.5 kPa or less, particularly 0.3 kPa or less in order to suppress coloring and deterioration of the product. It is preferable to be under a high vacuum.

  The polymer obtained by the polycondensation reaction is usually transferred from the bottom of the polycondensation reaction tank to a polymer extraction die and extracted in the form of a strand, and while being cooled with water or after being cooled with water, it is cut with a cutter to form pellets and chips. And so on.

  Furthermore, the PBT polycondensation reaction step is to once produce a PBT having a relatively small molecular weight by melt polycondensation, for example, an intrinsic viscosity of about 0.1 to 0.9, and then at a temperature below the melting point of the PBT. Solid phase polycondensation (solid phase polymerization) may be performed.

The intrinsic viscosity of the PBT of the present invention is not limited, but is a value measured at a temperature of 30 ° C. using a mixed solvent of 1,1,2,2-tetrachloroethane / phenol = 1/1 (weight ratio). 0.70 to 3.0, more preferably 0.80 to 1.5, and particularly preferably 0.80 to 1.2. If the intrinsic viscosity is less than 0.70, the mechanical properties are not exhibited, and if it is more than 3.0, molding becomes difficult. Two or more types of intrinsic viscosity polyester resins may be used in combination.

(B) Brominated Polycarbonate The (B) brominated polycarbonate used in the present invention is preferably a brominated polycarbonate obtained from brominated bisphenol A, particularly tetrabromobisphenol A. Examples of the terminal structure include 4-t-butylphenyl group and 2,4,6-tribromophenyl group. In order to improve the appearance gloss of the molded article of the present invention, those having a 2,4,6-tribromophenyl group in the terminal group structure are particularly preferred.

  Moreover, although the average of the carbonate repeating unit number in the (B) brominated polycarbonate used for this invention should just be selected and determined suitably, it is 2-30 normally. When the average number of carbonate repeating units is small, the melting point of polycarbonate decreases, and particularly when used together with polyester, the molecular weight of the polyester may decrease when melted. On the other hand, if it is too large, the melt viscosity of the polycarbonate becomes high, causing a dispersion failure in the molded product, which may deteriorate the appearance of the molded product, particularly the glossiness. Therefore, the average number of repeating units is preferably 3 to 15, particularly 3 to 10.

  The brominated polycarbonate obtained from the brominated bisphenol A can be obtained, for example, by an ordinary method in which brominated bisphenol and phosgene are reacted. Examples of the end-capping agent include aromatic monohydroxy compounds, which may be substituted with a halogen or an organic group.

  The content of (B) brominated polycarbonate in the present invention is 3 to 50 parts by weight, preferably 5 to 30 parts by weight, per 100 parts by weight of (A) polybutylene terephthalate. When the blending amount of the inorganic filler in the entire composition is increased or when a flame retardant aid described later is used, the blending amount of the flame retardant can be decreased, but even in that case, the object of the present invention is achieved. Requires at least 3 parts by weight. When the content of (B) brominated polycarbonate is less than 3 parts by weight per 100 parts by weight of (A) polybutylene terephthalate, the resulting PBT resin composition has insufficient flame retardancy, and conversely exceeds 50 parts by weight. And, the thermal stability at the time of melting is lowered, and the creep resistance is lowered.

(C) Antimony oxide compound Examples of the (C) antimony compound used in the present invention include antimony oxide and antimonate, and specific examples thereof include antimony trioxide (Sb ₂ O ₃ ) and antimony tetraoxide (Sb _2). Examples thereof include oxides such as O ₄ ) and antimony pentoxide (Sb ₂ O ₅ ), and antimonates such as sodium antimonate. From the viewpoint of price, antimony trioxide is preferable.

  The content of the (C) antimony compound in the polybutylene terephthalate resin composition of the present invention is 1 to 30 parts by weight with respect to 100 parts by weight of (A) polybutylene terephthalate. (C) If the content of the antimony compound is too small, the flame retardant effect is insufficient. Conversely, if the content is too large, the mechanical strength decreases and the thermal stability during melting tends to decrease. Therefore, the content of the (C) antimony compound is preferably 2 to 25 parts by weight, and particularly preferably 3 to 20 parts by weight with respect to 100 parts by weight of (A) polybutylene terephthalate.

(D) Reinforcing filler (D) Reinforcing filler used in the present invention is not particularly limited, and any conventionally known filler can be used. Specifically, for example, glass fibers, carbon fibers (carbon fibers), silica / alumina fibers, zirconia fibers, boron fibers, boron nitride fibers, silicon nitride potassium titanate fibers, inorganic fibers such as metal fibers, aromatic polyamide fibers, Examples thereof include organic fibers such as fluororesin fibers.
These reinforcing fillers may be used alone or in combination of two or more. Among these, inorganic reinforcing fillers are preferably used, and glass fibers can be particularly preferably used.
When the reinforcing filler (D) used in the present invention is an inorganic fiber or an organic fiber, the average fiber diameter is not particularly limited, but is preferably 1 to 100 μm, more preferably 2 to 50 μm, More preferably, it is 3-30 micrometers, and it is especially preferable that it is 5-20 micrometers. Moreover, although there is no restriction | limiting in particular also in average fiber length, it is preferable that it is 0.1-20 mm, It is more preferable that it is 1-10 mm, More preferably, it is 2-6 mm.

For example, the glass fiber may be appropriately selected and determined from the long fiber type (roving), the short fiber type (chopped strand), and the like, and the fiber diameter of the glass fiber to be used is usually 6 to 15 μm. The glass fiber may be treated with a bundling agent (eg, polyvinyl acetate, polyester, novolac epoxy compound, etc.), a coupling agent (eg, silane compound, aminosilane compound, boron compound, etc.), other surface treatment agents, etc. Good.

The reinforcing filler (D) used in the present invention is preferably a reinforcing filler surface-treated with a sizing agent or a surface treating agent in order to improve the interfacial adhesion with polybutylene terephthalate. Examples of the sizing agent or surface treatment agent include functional compounds such as epoxy compounds, acrylic compounds, isocyanate compounds, silane compounds, and titanate compounds.
The reinforcing filler can be surface-treated in advance with a sizing agent or a surface treatment agent,
Alternatively, a surface treatment can be performed by adding a sizing agent or a surface treatment agent during the preparation of the polybutylene terephthalate resin composition. The addition amount of the reinforcing filler is preferably 0 to 150 parts by weight with respect to 100 parts by weight of polybutylene terephthalate, and particularly preferably 5 to 100 parts by weight from the viewpoint of improving rigidity and dimensional stability. .

  In the flame-retardant polybutylene terephthalate resin composition of the present invention, other fillers can be blended together with the reinforcing filler. Other fillers to be blended include, for example, plate-like inorganic fillers, ceramic beads, asbestos, wollastonite, talc, clay, mica, zeolite, kaolin, potassium titanate, barium sulfate, titanium oxide, silicon oxide, oxidation Examples thereof include aluminum and magnesium hydroxide. By blending the plate-like inorganic filler, the anisotropy and warpage of the molded product can be reduced. Examples of the plate-like inorganic filler include glass flakes, mica, and metal foil. Among these, glass flakes can be particularly preferably used.

  In the flame-retardant polybutylene terephthalate resin composition of the present invention, flame retardants other than brominated aromatic compounds and antimony compounds can be blended. There is no restriction | limiting in particular in the flame retardant to mix | blend, For example, a fluorine resin, an organic chlorine type compound, a phosphorus compound, another organic flame retardant, an inorganic flame retardant etc. can be mentioned. An example of the fluororesin is polytetrafluoroethylene fiber. As a phosphorus compound, phosphate ester, polyphosphoric acid, ammonium polyphosphate, red phosphorus etc. can be mentioned, for example. Examples of other organic flame retardants include nitrogen compounds such as melamine cyanuric acid. Examples of other inorganic flame retardants include aluminum hydroxide, magnesium hydroxide, silicon compound, boron compound and the like.

  As polytetrafluoroethylene preferably used in the present invention, those having fibril forming ability are preferable. That is, it shows a tendency to easily disperse in the resin and to bond the polymers together to form a fibrous material, and functions as an anti-drip agent. Polytetrafluoroethylene having fibril-forming ability is classified as type 3 according to the ASTM standard. For example, Daikin Chemical Industries Polyflon FA-500 or F-201L, Asahi Glass Co. It is commercially available as Teflon (registered trademark) 6J manufactured by Chemical Corporation.

  The compounding quantity of polytetrafluoroethylene is 0.1-5 weight part with respect to 100 weight part of (A) polybutylene terephthalate. When the blending amount of polytetrafluoroethylene having fibril forming ability is less than 0.1 parts by weight, the effect of the present invention is not exhibited, and when it exceeds 5 parts by weight, processability such as extrudability and moldability is impaired. The blending amount of polytetrafluoroethylene having fibril-forming ability is preferably 0.2 to 4 parts by weight, more preferably 0.3 to 3 parts by weight with respect to 100 parts by weight of (A) polybutylene terephthalate. .

In the flame-retardant polybutylene terephthalate resin composition of the present invention, a conventional additive or the like can be blended with this kind of resin composition, if necessary. There are no particular restrictions on the additives to be added, for example, stabilizers such as antioxidants and heat stabilizers, additives such as lubricants, mold release agents, catalyst deactivators, crystal nucleating agents, and crystallization accelerators are polymerized. It can be added during or after polymerization. In addition, an epoxy compound, carbodiimide, oxazoline, or the like can be added to further improve the hydrolysis resistance. Furthermore, in order to impart desired performance to polybutylene terephthalate resin, stabilizers such as UV absorbers and weathering stabilizers, coloring agents such as dyes and pigments, antistatic agents, foaming agents, plasticizers, and impact resistance improvements An agent or the like can be blended.

The PBT resin composition of the present invention can be used in combination with a small amount of other thermoplastic resins as long as the purpose is not impaired. As the other thermoplastic resin used here, any thermoplastic resin may be used as long as it coexists with a halogenated epoxy compound as described above or is stable at a high temperature. For example, polyamide, polyacetal, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-butadiene-acrylonitrile copolymer, styrene-butadiene-acrylic acid (or ester thereof) copolymer, polycarbonate, polyurethane, Copolymers mainly composed of polyphenylene oxide, polyphenylene sulfide, polyethylene, polypropylene, polyethylene-propylene copolymer, epoxy-modified polyolefin copolymer, polybutadiene, halogenated polyolefin, polyhalogenated vinyl, butyl rubber, polyacrylate (multilayer graft copolymer) It is also possible to mix silicone resins and the like at any ratio depending on the purpose. One kind can be used alone, or two or more kinds can be used in combination.

  The method for producing the flame-retardant polybutylene terephthalate resin composition of the present invention is not particularly limited, and various general methods can be used. For example, (A) polybutylene terephthalate resin, (B) brominated polycarbonate A batch blending method in which a resin, (C) an antimony oxide compound, and (D) a reinforcing filler and other additives as necessary are mixed, and melted and kneaded by a screw type extruder to be pelletized; Polybutylene terephthalate is melted and kneaded with a screw-type extruder, and other components such as (D) reinforcing filler, and other additives as required, are melted and kneaded from the other supply port of the extruder. Split blending method to pelletize; once the pellets with different compositions are prepared, a predetermined amount of the pellets are mixed and used for molding, then the desired composition after molding How to obtain a molded product; or, a method in which charged one or more of the components directly into the molding machine.

  Such mixing can be performed by a commonly used method such as a ribbon blender, a Henschel mixer, a drum blender, or the like. For melt-kneading, any of various conventionally known extruders, Brabender plastographs, lab plast mills, kneaders, Banbury mixers and the like can be used. The temperature at the time of melt kneading is usually 230 to 290 ° C. Moreover, in order to suppress decomposition | disassembly of the various compounding components at the time of kneading | mixing, it is preferable to use the above-mentioned heat stabilizer.

  The resin composition of the present invention is molded by any conventionally known various molding methods such as injection molding, hollow molding, extrusion molding, compression molding, calendar molding, rotational molding, etc. It can be a molded product in the automobile field, machine field, medical field, or the like. Among them, the use of a molding method by injection molding utilizing the high fluidity that is a feature of the resin composition of the present invention is industrially advantageous because productivity is improved. In the injection molding, the resin temperature is preferably controlled to 240 to 280 ° C.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples as long as the gist thereof is not exceeded.
<Raw materials used in Examples and Comparative Examples>
(A) PBT production method (A-1 to A-8)

(A-1) :
Using the esterification step shown in FIG. 1 and the polycondensation step shown in FIG. 2, PBT was produced by the following method. First, a 60 ° C. slurry mixed at a ratio of 1.80 mol of 1,4-butanediol with respect to 1.00 mol of terephthalic acid was passed through the raw material supply line 1 from the slurry preparation tank in advance with an esterification rate of 99%. Was continuously fed to the reaction tank A for esterification having a screw type stirrer filled with PBT oligomer of 41 kg / h. At the same time, the bottom component of the rectifying column C at 185 ° C. (98% by weight or more is 1,4-butanediol) is supplied at 20 kg / h from the recirculation line 2 and the catalyst at 65 ° C. is supplied from the titanium catalyst supply line 3 as a catalyst. A 6.0 wt% 1,4-butanediol solution of tetrabutyl titanate was fed at 99 g / h (30 ppm relative to the theoretical polymer yield). The water content in this catalyst solution was 0.2% by weight. A 6.0 wt% 1,4-butanediol solution of magnesium acetate tetrahydrate at 65 ° C. was fed as a catalyst at 62 g / h from the group 2 metal catalyst feed line 15 (15 ppm based on the theoretical polymer yield). The water content in this catalyst solution was 10.0% by weight.

  The internal temperature of the reaction tank A is 230 ° C., the pressure is 78 kPa, and water to be generated, tetrahydrofuran and excess 1,4-butanediol are distilled from the distillation line 5. Separated into boiling components. The high-boiling component at the bottom of the column after the system is stabilized is 98% by weight or more of 1,4-butanediol, and a part of the high-boiling component through the extraction line 8 so that the liquid level of the rectifying column C is constant. Extracted outside. On the other hand, the low boiling component was extracted from the top of the column in the form of gas, condensed by the condenser G, and extracted from the extraction line 13 to the outside so that the liquid level of the tank F was constant.

  A certain amount of the oligomer generated in the reaction tank A was extracted from the extraction line 4 using the pump B, and the liquid level was controlled so that the average residence time of the liquid in the reaction tank A was 2.5 hr. The oligomer extracted from the extraction line 4 was continuously supplied to the first polycondensation reaction tank a shown in FIG. After the system was stabilized, the esterification rate of the oligomer collected at the outlet of the reaction tank A was 96.5%.

  The internal temperature of the first polycondensation reaction tank a was 240 ° C., the pressure was 2.1 kPa, and the liquid level was controlled so that the residence time was 120 minutes. An initial polycondensation reaction was performed while extracting water, tetrahydrofuran and 1,4-butanediol from a vent line L2 connected to a decompressor (not shown). The extracted reaction liquid was continuously supplied to the second polycondensation reaction tank d.

  The internal temperature of the second polycondensation reaction tank d is 240 ° C., the pressure is 130 Pa, the liquid level is controlled so that the residence time is 85 minutes, and water is supplied from a vent line L4 connected to a decompressor (not shown). Further, the polycondensation reaction was advanced while extracting tetrahydrofuran and 1,4-butanediol. The obtained polymer was continuously extracted in a strand form from the die head g via the extraction line L3 by the extraction gear pump e, and was cut by the rotary cutter h. The analytical values of the obtained PBT are shown in Table 1.

(A-2) :
In (A-1), the residence time of the second polycondensation reaction tank d is set to 60 minutes, and the obtained polymer chip is 195 ° C. under reduced pressure (0.133 kPa or less) in a double conical blender (with an internal volume of 100 liters). ) A solid state polymerization treatment for 5 hours was performed. The intrinsic viscosity of the polymer subjected to the solid phase polymerization treatment was 0.85 dL / g, and the terminal carboxyl group concentration was 5.1 μeq / g. The analytical values of the obtained PBT are shown in Table 1.

(A-3) :
In (A-1), the supply amounts of tetrabutyl titanate and magnesium acetate tetrahydrate are adjusted so that the contents of titanium and magnesium in the polymer are as shown in Table 1, and in the second polycondensation reaction tank d. The procedure was the same as (A-1) except that the residence time was 75 minutes. The analytical values of the obtained PBT are shown in Table 1.

(A-4) :
In (A-1), the supply amounts of tetrabutyl titanate and magnesium acetate tetrahydrate are adjusted so that the contents of titanium and magnesium in the polymer are as shown in Table 1, and the temperature of the second polycondensation reaction tank d Was performed in the same manner as (A-1) except that the temperature was 244 ° C. and the residence time was 75 minutes. The analytical values of the obtained PBT are shown in Table 1.

(A-5) :
In (A-1), lithium acetate dihydrate is used in place of magnesium acetate tetrahydrate, the supply amount is adjusted so that the titanium and lithium contents in the polymer are as shown in Table 1, and the second The same procedure as (A-1) was performed except that the temperature of the polycondensation reaction tank d was 244 ° C. and the residence time was 70 minutes. The analytical values of the obtained PBT are shown in Table 1.

(A-6) :
In (A-1), magnesium acetate tetrahydrate is not used, and the supply amount of tetrabutyl titanate is adjusted so that the titanium content in the polymer is as shown in Table 2. Was carried out in the same manner as (A-1) except that the residence time of was changed to 105 minutes. The analytical values of the obtained PBT are shown in Table 1.

(A-7) :
In (A-1), the supply amount of tetrabutyl titanate and magnesium acetate tetrahydrate is adjusted so that the titanium and magnesium contents in the polymer are as shown in Table 1, and the second polycondensation reaction tank d is retained. The procedure was the same as (A-1) except that the time was 75 minutes. The analytical values of the obtained PBT are shown in Table 1.

(A-8) :
In (A-1), the feed amounts of tetrabutyl titanate and magnesium acetate tetrahydrate are adjusted so that the contents of titanium and magnesium in the polymer are as shown in Table 1, and the second polycondensation reaction tank (d) Was carried out in the same manner as (A-1) except that the residence time was 90 minutes. The analytical values of the obtained PBT are shown in Table 1.
Evaluation method of PBT characteristics

(1) Esterification rate:
It calculated from the acid value and saponification value by the following formula. The acid value was obtained by dissolving the oligomer in dimethylformamide and titrating with a 0.1N KOH / methanol solution. The saponification value was determined by hydrolyzing the oligomer with a 0.5N KOH / ethanol solution and titrating with 0.5N hydrochloric acid.
Esterification rate = (saponification value−acid value) / saponification value) × 100

(2) Terminal carboxyl group concentration:
0.5 g of PBT or oligomer was dissolved in 25 ml of benzyl alcohol, and titrated using a 0.01 mol / L benzyl alcohol solution of sodium hydroxide.

(3) Intrinsic viscosity (IV):
It calculated | required in the following way using the Ubbelohde type viscometer. That is, using a mixed solvent of phenol / tetrachloroethane (weight ratio 1/1), at 30 ° C., the polymer solution having a concentration of 1.0 g / dl and the number of falling seconds of the solvent alone were measured, and obtained from the following formula. .

IV = ((1 + 4K _H η _sp ) ^0.5 −1) / (2K _H C) (2)
(Where η _sp = η / η ₀ −1, η is the polymer solution dropping time, η ₀ is the solvent dropping time, C is the polymer solution concentration (g / dL), and K _H is the Huggins constant. Yes, 0.33.
)

(4) Titanium and group 1 and group 2 metal concentrations in PBT:
PBT is wet-decomposed with high-purity sulfuric acid and nitric acid for electronics industry, and high-resolution ICP-MS (Ind
The measurement was performed using an activated Coupled Plasma-Mass Spectrometer (manufactured by ThermoQuest).

(5) Pellet color tone:
A color difference meter (Z-300A type) manufactured by Nippon Denshoku Co., Ltd. was used, and the b value in the L, a, b color system was evaluated. A lower value indicates less yellowing and a better color tone.

Raw materials other than PBT (A) (B-1) Brominated polycarbonate oligomer (FR-53 manufactured by Mitsubishi Gas Chemical Company, bromine content 59%, average number of carbonate repeating units is 5)
(B-2) Polypentabromobenzyl acrylate (Bromochem Far East, PBBPA-FR1025, bromine content: 70%) (B-3) Brominated polystyrene (Manac, Plasticity 1200Z, bromine content: 68%)
(C) Antimony trioxide (Moroku 6)
(D) Glass fiber (manufactured by Nippon Electric Glass Co., Ltd .: T-187 diameter 13 μm, fiber length 3 mm)
<Evaluation method>

Each component was weighed in the proportions shown in Table 2 so that the bromine concentration was 6.2%, and all the components other than glass fiber were mixed together to form a twin screw extruder (manufactured by Nippon Steel Works, model TEX30C, screw The glass fiber was side fed at a cylinder set temperature of 255 ° C. and a screw rotation speed of 200 rpm using a diameter of 30 mm), and compounded according to a conventional method to obtain pellets. In Example 6, a composition obtained by adding 608 ppm of magnesium stearate (25 ppm as metallic magnesium) to the composition of Comparative Example 1 was similarly compounded.
Using the injection pellet machine (model SG-75SYCAP-MIII) manufactured by Sumitomo Heavy Industries, Ltd., the following various test specimens were subjected to the following pellets at a cylinder temperature of 250 ° C and a mold temperature of 80 ° C. It shape | molded and the performance evaluation was performed with the following test method. The results are shown in Table 2.

Flame retardancy test The flame retardancy test was conducted according to UL94 test method. The sample thickness was 1/32 inch, and the burning time was obtained as an average of the results obtained with five samples.
Tensile test Measured according to ISO527. The unit of strength is MPa.
Tensile creep test A specimen for tensile impact was molded, and a creep rupture time was determined using a creep tester manufactured by Toyo Seiki Seisakusho at a load of 27 kg and a set temperature of 100 ° C. The number of measurements was two, and the average rupture time was displayed. The larger the value, the better the creep resistance. In addition, the test piece for tensile impact is a 4 type test piece based on ISO294 (width 3mm, thickness 1.8mm).
Measurement of generated gas amount 5 g of polybutylene terephthalate resin composition pellets are placed in a glass vial with an internal volume of 26 ml, heated at 150 ° C. for 2 hours, a sample is taken from the gas phase using a microsyringe, and gas chromatography is performed. Analyzed by graphy. The main component of the generated gas is tetrahydrofuran. The total peak area on the chromatogram was obtained, and the weight of tetrahydrofuran corresponding to the area was defined as the ratio (ppm) to the resin. The smaller the value, the less the generated gas and the better.

When Examples (1-6) and Comparative Examples (1-3) shown in Table 2 were compared, all the examples had excellent creep resistance and a small amount of generated gas. became. It is clear that the comparative example in which the content of Ti or Mg is outside the range of the present invention is a resin composition that is not well-balanced because either creep resistance or low-generated gas characteristics are lowered.
Moreover, when Example 1 and Comparative Examples 4 and 5 are compared, the Comparative Example using a flame retardant other than brominated polycarbonate is that both creep resistance and low gas generation characteristics are lower than Example 1. I understand.
From these results, the resin molded product formed by molding the polybutylene terephthalate resin composition of the present invention is excellent in mechanical properties, creep resistance and gas generation suppression effect, and cracking occurs even in a high temperature atmosphere. It can be seen that the contact corrosion is suppressed, and it is possible to meet high quality requirements for relay parts and the like.
And it is expected that it can be used in a wide variety of fields such as electric and electronic equipment, automobile, and machinery.

(A) Explanatory drawing of an example of esterification (or transesterification) reaction process in PBT production (A) Explanatory drawing of an example of a polycondensation process in PBT production

Explanation of symbols

1: Raw material supply line 2: Recirculation line 3: Titanium catalyst supply line 4: Extraction line 5: Distillation line 6: Extraction line 7: Circulation line 8: Extraction line 9: Gas extraction line 10: Condensate Line 11: Extraction line 12: Circulation line 13: Extraction line 14: Vent line 15: 2A group metal catalyst supply line A: Reaction tank B: Extraction pump C: Rectification tower D: Pump E: Pump F: Tank G: Capacitor L1: Extraction line L2: Vent line L3: Extraction line L4: Vent line a: First polycondensation reaction tank c: Extraction gear pump d: Second polycondensation reaction tank e: Extraction gear pump g : Dice head

Claims (6)

  (A) 3 to 50 parts by weight of a brominated polycarbonate, (C) 1 to 30 parts by weight of an antimony oxide compound, and (D) 0 to 150 parts by weight of a reinforcing filler with respect to 100 parts by weight of the polybutylene terephthalate resin. (A) the polybutylene terephthalate resin contains (a) a titanium compound and (b) a Group 1 metal compound and / or a Group 2 metal compound, and (a) the content of the titanium compound is in terms of titanium atoms. And (b) a polybutylene terephthalate resin composition having a group 1 metal compound and / or group 2 metal compound content of 1 ppm to 50 ppm in terms of metal atoms.   2. The polycondensation catalyst for producing (A) polybutylene terephthalate resin, wherein (a) the titanium compound and (b) the Group 1 metal compound and / or the Group 2 metal compound are (1). Polybutylene terephthalate resin composition.   (B) The polybutylene terephthalate resin composition according to claim 1 or 2, wherein the Group 1 metal compound or Group 2 metal compound is a magnesium compound.   A polybutylene terephthalate resin molded product obtained by molding the polybutylene terephthalate resin composition according to any one of claims 1 to 3.   5. The polybutylene terephthalate resin molded product according to claim 4, which is molded by an insert molding method. An electrical / electronic component for relays comprising the polybutylene terephthalate resin molded product according to claim 4.

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