JP2908648B2 - Method for producing modified polybutylene terephthalate resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a stable modified polybutylene terephthalate resin which generates a small amount of gas such as tetrahydrofuran when used at a high temperature and which has a small amount of sublimate during melt processing. The present invention relates to a molded article comprising the prepared modified polybutylene terephthalate resin or a composition thereof.

[0002]

2. Description of the Related Art Polybutylene terephthalate (hereinafter sometimes abbreviated as PBT) is a crystalline thermoplastic resin having mechanical, electrical, chemical, and physical properties. And so on,
It is used as a engineering plastic in a wide range of applications such as automobiles and electric / electronic devices. Further, it has excellent fragrance retention properties and gas barrier properties against water vapor and the like, and is also used heavily in the field of packaging of containers for food products, cosmetics, etc., and packaging films. However, PBT has a problem in the molding process. When heated in a molten state, gas or sublimate is generated due to decomposition of the resin, which causes voids in a molded product, It may adhere to molding equipment such as rolls and cause contamination or corrosion. Also, in the actual production process, the molding operation of the resin is not always performed continuously, and the molding operation is often performed intermittently. In such a case, the resin is in a molten state for a long time in the molding machine. The problem of gas and sublimate generation is particularly serious due to easy retention, and improvement is desired. In addition, molded products using these PBTs generate gas such as tetrahydrofuran even when used at high temperatures, and contaminate or corrode metal contacts in electric or electronic components such as relays, switches and connectors. In addition, containers such as foods, beverages, cosmetics, packaging films, and the like have a problem in that an odor is transferred to the contents and taste is impaired. Thus, reducing gas generation in molded articles is also a much-desired problem.

[0003]

In view of such demands, the present inventors have maintained excellent physical properties of a PBT-based resin, and furthermore, generated a small amount of gas such as tetrahydrofuran when used at high temperatures, and sublimated during melting. As a result of intensive studies to obtain a modified polybutylene terephthalate resin having a small physical quantity, the present inventors have reached the present invention. That is, the present invention provides a polyester by subjecting an acid component mainly composed of terephthalic acid or its lower alcohol ester and a diol component mainly composed of 1,4-butanediol to a polycondensation via an esterification or transesterification reaction. Prior to the completion of the polycondensation reaction, at least one compound represented by the following general formula (A) is used in the production, in an amount of 0.001 to 0.5 mol% based on the acid component.
A method for producing a modified polybutylene terephthalate resin characterized by being added, and a molded article comprising a modified PBT resin produced by the production method or a composition thereof.

[0004]

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( Wherein R is selected from a hydrogen atom or an alkyl group having 1 to 30 carbon atoms (each of which may have a branched structure) and may be the same or different. M is a tetraalkylphosphonium, The modified polybutylene terephthalate resin of the present invention comprises an acid component mainly composed of terephthalic acid or a lower alcohol ester thereof, which is selected from the group consisting of an alkyl ammonium, lithium, sodium, potassium, barium, and calcium. ,Four
-Main component is a butylene terephthalate unit obtained from a diol component mainly containing butanediol, and includes a homopolyester and a copolyester.

In preparing a copolymerized polyester,
In addition to the main constituent acid component as the acid component comonomer, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diphenic acid, adipic acid, sebacic acid, dodecanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid It is possible to use one or two or more of conventionally known bifunctional carboxylic acids such as acids or dimethyl esters thereof or lower alcohol esters thereof. In addition, as the diol component comonomer, in addition to the main component diol component, ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propanediol, neopentyl glycol, 1,6-hexanediol, 1,10-decanediol, 4-cyclohexanediol, p-xylylene glycol, alkylene oxide adduct of hydroquinone, alkylene oxide adduct of 2,2-bis (4-hydroxyphenyl) propane, alkylene oxide adduct of bis (4-hydroxyphenyl) sulfone, One or more conventionally known bifunctional diols such as an ethylene oxide adduct of 2,6-dihydroxynaphthalene can be used. Further, as a comonomer, a halogen-substituted product of the above substances may be used to impart flame retardancy. Also, trifunctional or higher polyfunctional compounds such as trimethyl trimesate, trimethyl trimellitate, trimethylolpropane and pentaerythritol, stearyl alcohol, methyl o-benzoylbenzoate, monofunctional compounds such as epoxy-containing compounds,
It is also possible to use a small amount of a hydroxycarboxylic acid derivative such as methyl p-hydroxyethoxybenzenecarboxylate, a polyalkylene glycol such as polypropylene glycol or polytetrahydrofuran, or to use in combination with the above copolymerization component. The introduction amount of these copolymer components is
Preferably 30 mol% based on all constitutional repeating ester units
Or less, particularly preferably 20 mol% or less.

In the production of the modified polybutylene terephthalate resin according to the present invention, at least one of the compounds represented by the general formula (A) is added in an amount of 0.001 to 0.5 mol% based on the acid component before the completion of the polycondensation reaction. It is characterized by the following. Examples of the compound represented by the concrete formula (A), sulfo succinic anhydride, alpha,. Alpha .'- diethyl -α- sulfo tetrabutylphosphonium anhydride and succinic acid, tetrabutyl ammonium salt, lithium salt, Examples thereof include a sodium salt, a potassium salt, a barium salt and a calcium salt. These sulfonic acid compounds represented by the general formula (A) need to be added at any time from the monomer preparation stage to the completion of the polycondensation reaction, and may be added in several stages at any stage. It is possible. In particular, the general formula
The sulfonic acid compound represented by (A) may be added in advance in the raw material monomer during the polycondensation reaction via esterification or transesterification of the acid component and the diol component, or may be esterified or esterified. Stages before the exchange reaction is substantially complete are preferred. That is, it is added to the monomer before the addition of the reaction catalyst, or when a lower alcohol ester of carboxylic acid is used as the acid component as a raw material, the lower alcohol generated by transesterification with the diol component is distilled out of the reaction system. Before the amount reaches 90 mol% of the theoretical distillate amount, or when carboxylic acid is used as the acid component, the amount of water distilled out of the reaction system generated by the esterification reaction with the diol component is the theoretical amount. It is preferable to add the compound to the reaction system before reaching 90 mol% of the distillation amount. That is, the effect of reducing the amount of generated gas such as tetrahydrofuran at the time of high temperature use of the molded article, and the amount of sublimate during the melt processing is more remarkable as the sulfonic acid compound is added at the earlier stage in the polyester formation reaction process, as described above. Is obtained. On the other hand, if it is mixed with polymer pellets once produced by polymerization using an extruder or the like, the effect is undesirably reduced. In addition, it is preferable to add to the system as a solution previously dissolved or suspended in 1,4-butanediol or the like. The amount of the above-mentioned sulfonic acid compound added alone or in combination of two or more is 0.001 to 0.5 mol% based on the acid component monomer. A particularly preferred addition amount is 0.01 to 0.3 mol%. 0.001 mol%
If the amount is less, the effect of reducing the amount of gas generated from tetrahydrofuran and the amount of sublimate at the time of melting at the high temperature use of the molded product is small. As it is, it remains as fine foreign matter in the polymerized product, resulting in poor appearance of the molded product, reduced mechanical strength, etc.

In the method of the present invention, when a lower alcohol ester of terephthalic acid is used as the acid component, the transesterification is carried out by reacting the lower alcohol ester of terephthalic acid with 1,4-butanediol in a molar ratio of 1: 1 to 1: 2. Under normal pressure. Examples of the catalyst for obtaining a practical reaction rate include titanium compounds, tin compounds, lead oxide, lead acetate, zinc acetate, zinc oxide, and manganese acetate. Among them, organic titanate compounds, titanium tetrachloride compounds and the like Hydrolysates or alcoholysis, tin oxide, tin acetate, organotin compounds and the like are preferred. Specifically, tetrabutyl titanate, tetrapropyl titanate, tetraethyl titanate, tetramethyl titanate and their hydrolysates, hydrolysates such as titanium tetrachloride and titanium sulfate, titanium fluoride potassium, titanium zinc fluoride, titanium cobalt fluoride and the like And / or dibutyltin oxide, dibutyltin acetate, dioctyltin diacetate, diphenyltin dilauryl mercaptide, polydibutyltin sebacate, dibutyltin Ethylene glycolate, dioctyltin thiosalicylate, diphenyltin benzenesulfonate,
As a catalyst for producing a polyester such as dimethyltin-p-toluenesulfonate, a conventionally known tin compound may be mentioned. Particularly preferred are tetrabutyl titanate, tetrapropyl titanate, hydrolyzate of titanium tetrachloride, dibutyltin oxide, dibutyltin acetate, dioctyltin diacetate and the like. The amount of these catalysts to be used is preferably 10 to 1200 as titanium and tin (in the case of a mixed system, the total thereof) when a titanium compound system, a tin compound system and a mixture thereof are taken as examples.
ppm (based on polymer), particularly preferably 30 to 1000 ppm (based on polymer), and if necessary, it can be added in several portions during the reaction. After this, the reaction temperature
It is possible to raise the temperature to 230 ° C or lower while removing continuously formed lower alcohols such as methanol.

The esterification reaction using terephthalic acid as a main raw material as an acid component is carried out under normal pressure or pressure at a ratio of 1 to 5 mol of 1,4-butanediol to 1 mol of terephthalic acid. The reaction is carried out by adding an esterification reaction catalyst such as a titanium compound or a tin compound to continuously remove water, and the catalyst can be divided into several times during the reaction, if necessary. After this, the reaction temperature 250 ℃
It can be raised to:

In the polycondensation reaction, the product obtained by the above transesterification or esterification reaction is reacted at 190 to 270 ° C.
The pressure in the reaction system is reduced to carry out melt polymerization while continuously removing excess 1,4-butanediol and reaction by-products until a desired degree of polymerization is obtained. As the catalyst for obtaining a practical reaction rate in the polycondensation reaction, the catalyst used in the above-mentioned transesterification reaction or esterification reaction can be used as it is, and in order to improve the speed of the polycondensation reaction, It is also possible to add one or more of these before starting the reaction. It is also possible to add a conventionally known stabilizer such as a sterically hindered phenol or a phosphorus compound to the monomer preparation step or the polymerization step. The sulfonic acid compound added in the present invention has no adverse effect on the rate of the polycondensation reaction at the addition amount specified in the present invention, and does not hinder the polycondensation reaction at all.

[0011] The modified polybutylene terephthalate of the present invention obtained by melt polymerization is composed of 25
It has an intrinsic viscosity at a temperature of the order of 0.5 to 1.2, which is then cooled, solidified and ground or pelletized. When a high degree of polymerization is required, it is also possible to shift to solid phase polymerization depending on the application. The solid-phase polymerization is generally performed by a known method, and the desired degree of polymerization can be appropriately adjusted by the residence time, the treatment temperature and the like.

The modified polybutylene terephthalate resin of the present invention may be used, if necessary, during polymerization or after polymerization of one or more of other thermoplastic resins, additives, organic fillers, inorganic fillers and the like. It can also be used as a composition which is added and blended. Here, as the thermoplastic resin, polyester elastomer and polyester resin other than the present invention, polyolefin resin, polystyrene resin,
Examples include polyamide resins, polycarbonates, polyacetals, polyarylene oxides, polyarylene sulfides, and fluororesins. Further, as additives, conventionally known stabilizers such as ultraviolet absorbers and antioxidants, antistatic agents, flame retardants, flame retardant aids, coloring agents such as dyes and pigments,
Lubricants, plasticizers, lubricants, release agents, nucleating agents and the like are exemplified. In addition, as the inorganic filler, glass fiber, milled glass fiber, glass beads, glass flake, silica, alumina fiber, zirconia fiber, potassium titanate fiber, carbon fiber, carbon black, graphite, calcium silicate, aluminum silicate, kaolin, Silicates such as talc and clay, iron oxides, titanium oxide, zinc oxide, antimony oxide, metal oxides such as alumina, calcium, magnesium, carbonates and sulfates of metals such as zinc, and further silicon carbide, silicon nitride, Examples of the organic filler include aromatic polyester fibers having a high melting point, liquid crystalline polyester fibers, aromatic polyamide fibers, fluororesin fibers, and polyimide fibers. When used as a molded article for electric / electronic parts or automobile parts, there are many cases where flame retardancy is required depending on the use environment, and it is often necessary to blend a flame retardant and a flame retardant auxiliary. As the flame retardant, known halogen-containing compound flame retardants such as brominated polycarbonate, brominated epoxy compound, brominated diphenyl, and brominated diphenyl ether can be used.
In addition to antimony compounds such as antimony trioxide, antimony pentoxide, and antimony halide,
Metal compounds containing zinc and bismuth, and clayey silicates such as magnesium hydroxide and asbestos can be used.
It is preferable to use an appropriate amount of a stabilizer such as an antioxidant in order to further improve the effects of the present invention.

The modified PBT resin and its composition of the present invention can be applied to various molding methods such as injection molding, extrusion molding, blow molding, compression molding, vacuum molding, etc., and various molded parts, films, sheets, etc. Processed into various applications.

[0014]

The modified polybutylene terephthalate resin produced according to the present invention has excellent physical properties, particularly excellent stability during melt molding, a small amount of decomposition sublimates generated, and a high temperature use. Generates little gas such as tetrahydrofuran, and does not cause contamination or corrosion of metal parts as electric or electronic parts such as relays, switches, connectors, etc., and can be used as food, cosmetic containers, packaging films, etc. Suitable without contamination.

[0015]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.
In addition, the characteristic evaluation of the produced resin was performed as follows. (1) Measurement of generated gas and the amount of generated gas An ASTM No. 1 tensile test piece was prepared under a certain condition using an injection molding machine, and this was pulverized to a certain particle size to obtain a sample.
5 g of a sample was taken, left in a 20 ml head space at 140 ° C. for 2 hours, and the generated gas was measured by gas chromatography under the following conditions. The weight of the generated gas is shown in ppm with respect to the weight of the sample. Equipment: Yokogawa Hewlett-Packard HP58
90A column; HR-1701, 0.32mm diameter x 30m Column temperature; 50 ° C (1 minute) → 5 ° C / min → 250 ° C
(1 minute) Detector; FID (2) Melting weight loss measurement Using a thermogravimetric analyzer (Perkin Elmer, TGA-7), melt and heat at 260 ° C in a nitrogen flow atmosphere using a 10 mg sample cut from pellets. The rate of weight loss during 10 minutes between 5 minutes and 15 minutes was measured. (3) Evaluation of mechanical strength Izod impact strength (notch side) was measured according to ASTM D256.

Examples 1-2 and Comparative Examples 1-3 After a reactor equipped with a stirrer and a distillation column was sufficiently purged with nitrogen, 246 parts by weight of dimethyl terephthalate (DMT), 1,4
145 parts by weight of butanediol (1,4 BD), the amount of the following compound (Aa) or (Ab) shown in Table 1 and 0.16 part by weight of titanium tetrabutoxide as a catalyst were charged, and the transesterification reaction was carried out. The temperature was gradually increased, and methanol as a by-product was distilled off. When the distilled methanol exceeds 88% by weight of the theoretical amount, the temperature of the reactant is increased to 200 ° C., and then transferred to another reactor, and the reaction is carried out for 0.5 hour in one hour.
The pressure was reduced to torr and the reaction temperature was raised to 250 ° C at the same time.After stirring for 1.5 hours in this state, the melt was extruded as a strand from the discharge port, the strand was cooled with water, and adhering water was passed under hot air. The pellet was removed to obtain a pelletized modified PBT resin.

[0017]

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The intrinsic viscosity of the obtained polyester was measured in orthochlorophenol at 25 ° C., and the above characteristics were evaluated. Gases such as 1-butene, tetrahydrofuran, and 3-buten-1-ol were observed as the generated gas. Table 1 shows the results. If it does not at all use the sulfonic acid compound for comparison (Comparative Example 1), one as well general formula
The following compound (B) different from the structure represented by (A),
The same evaluation was performed when (C) was used. The results are shown in Table 1 .

[0019]

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[0020]

[Table 1]

Continuation of the front page (56) References JP-A-1-197523 (JP, A) JP-A-1-172425 (JP, A) JP-A-1-103650 (JP, A) JP-A-4-359016 (JP) , A) Tokiko 47-22334 (JP, B1)

Claims (3)

(57) [Claims] A polyester is obtained by subjecting an acid component mainly composed of terephthalic acid or a lower alcohol ester thereof and a diol component mainly composed of 1,4-butanediol to polycondensation through an esterification or transesterification reaction. In the production, before completion of the polycondensation reaction, the following general formula
A process for producing a modified polybutylene terephthalate resin, comprising adding at least one compound represented by the formula (A) to the acid component in an amount of 0.001 to 0.5 mol%. Embedded image (However, R is selected from a hydrogen atom or an alkyl group having 1 to 30 carbon atoms and may be the same or different. M is selected from tetraalkylphosphonium, tetraalkylammonium, lithium, sodium, potassium, barium and calcium. Group or element) 2. The addition time of the compound represented by the general formula (A) is determined by the amount of water produced by the esterification reaction and the amount of distilling out of the reaction system, or the lower alcohol produced by the transesterification reaction to the outside of the reaction system. The method for producing a modified polybutylene terephthalate resin according to claim 1, wherein the amount of distillate is before reaching 90 mol% of the theoretical amount of distillate. 3. A molded article comprising a modified polybutylene terephthalate resin produced by the production method according to claim 1 or a composition thereof.