JPH10245477A - Flame-resistant polyester resin composition and its preparation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a flame-resistant polyester resin composition capable of improving the extrusion processability without damaging the excellent mechanical characteristics and flame resistance, and stable in quality, by using a specific polytetrafluoroethylene as a drip-preventing agent. SOLUTION: This flame-resistant polyester resin composition comprises (A) a thermoplastic resin, (B) 1-30wt.% organic halogen-based flame retardant and (C) 0.05-5wt.% polytetrafluoroethylene obtained by a suspension polymerization and having 10-1000μm particle diameter, and further preferable 1-60wt.% one or more kinds of inorganic fillers, especially one or more kinds selected from among a glass fiber, glass beads and glass flakes. The objective composition is preferably prepared by adding the component C as it is, or after pulverizing, or after forming into a coagulated granule having 10-1000μm particle diameter to other components, and mixing and kneading the components with the added component C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a flame-retardant polyester resin composition and a method for preparing the same. More specifically, without impairing excellent mechanical properties and flame retardancy,
An object of the present invention is to provide an inexpensive resin composition having improved extrudability and stable quality.

[0002]

2. Description of the Related Art Thermoplastic polyester resins such as polyalkylene terephthalate resins have mechanical properties, electrical properties, and other physical properties.
Due to its excellent chemical properties, it is used as a engineering plastic in a wide range of applications such as automobiles, electric and electronic equipment. Conventionally, for applications where flame retardancy is required, such as electric parts in general, mainly organic halogen-based flame retardants,
It has been practiced to add a flame retardant auxiliary or to introduce a flame retardant group into the polymer itself to make the polymer flame retardant. In addition, depending on the use, the composition may be required to have a Vo of UL standard 94, and it is required to prevent dripping during combustion. It has been proposed that polytetrafluoroethylene be used in combination with a flame retardant or the like as a solution to such a demand for drip prevention (Japanese Patent Publication No. 55-30024). However, according to additional tests by the present inventors, polytetrafluoroethylene conventionally used generally, for example, the above-mentioned Japanese Patent Publication No. 55-3
Polytetrafluoroethylene (Teflon type-6 manufactured by DuPont) recommended in No. 0024 works effectively for drip prevention, but has a property of easily flowing due to a slight shearing force. At the time of its preparation, it was found that various problems such as the following inconveniences and complications in operation were caused, and satisfactory physical properties could not be stably obtained. That is, when polytetrafluoroethylene is mixed with other components such as a polyester resin and a flame retardant, the polytetrafluoroethylene aggregates or
It has the effect of spreading in a fibrous form and aggregating other components. Therefore, it adheres, accumulates and closes on the machine wall such as rotating equipment, extruder or piping at the time of transportation, and causes surging, strand breakage, etc. due to deterioration of function of each equipment or poor biting into the extruder, etc. In some cases, the time required for disassembly and cleaning was required, and productivity was significantly impaired. In order to prepare a composition containing polytetrafluoroethylene in order to avoid these obstacles, this is preliminarily mixed with a polyester resin powder, a flame retardant, etc. to form a masterbatch, which is further mixed with the remaining polyester resin pellets ( Means such as two-stage blending and feeding to an extruder are required, which not only increases the production cost, but also makes smooth operation difficult. Such operational instability affects the physical properties of the product composition, resulting in a decrease in quality and an increase in variation, and a solution to the problem has been eagerly desired.

[0003]

In view of such demands, the present inventors have improved the problems (workability, quality variation, etc.) in preparing a polytetrafluoroethylene-containing flame-retardant polyester resin composition. As a result of thorough investigation and research on the type, morphology, formation process, post-treatment, etc. of polytetrafluoroethylene used as an anti-drip agent, the polymer obtained by the suspension polymerization method was used as the polymerization method. The inventors have found that tetrafluoroethylene is extremely effective in achieving this purpose, and arrived at the present invention. That is, the present invention relates to (A) a thermoplastic polyester resin, (B) 1 to 30% by weight of an organic halogen-based flame retardant (in the composition), and (C) a polymer having a particle size of 10 to 1000 μm obtained by a suspension polymerization method. An object of the present invention is to provide a flame-retardant polyester resin composition containing 0.05 to 5% by weight (in the composition) of tetrafluoroethylene.

[0004]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the constituent components of the composition of the present invention will be described in detail. First, the thermoplastic polyester resin (A) used in the present invention is a polyester obtained by polycondensation of a dicarboxylic acid compound and a dihydroxy compound, polycondensation of an oxycarboxylic acid compound, or polycondensation of a mixture of these three components. polyester,
The effect of the present invention can be applied to any of the copolyesters.
Illustrative examples of dicarboxylic acid compounds used here include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid,
Known dicarboxylic acids such as diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylethanedicarboxylic acid, cyclohexanedicarboxylic acid, adipic acid and sebacic acid, and alkyl, alkoxy or halogen-substituted products thereof. These dicarboxylic acid compounds can also be used for polymerization in the form of a derivative capable of forming an ester, for example, a lower alcohol ester such as dimethyl ester. Two or more of these may be used. Next, examples of the dihydroxy compound constituting the polyester of the present invention include ethylene glycol, propylene glycol, butanediol, neopentyl glycol, hydroquinone, resorcinol, dihydroxyphenyl, naphthalene diol, dihydroxydiphenyl ether, cyclohexanediol, and 2,2-. Examples thereof include dihydroxy compounds such as bis (4-hydroxyphenyl) propane and diethoxylated bisphenol A, polyoxyalkylene glycols, and alkyl, alkoxy or halogen-substituted products thereof, and one or more of them can be used in combination. Examples of oxycarboxylic acids include oxycarboxylic acids such as oxybenzoic acid, oxynaphthoic acid, and diphenyleneoxycarboxylic acid, and alkyl, alkoxy or halogen-substituted products thereof.
Further, derivatives of these compounds capable of forming an ester can also be used. In the present invention, one or two of these compounds
More than one species is used. In addition, a polyester having a branched or crosslinked structure using a small amount of a trifunctional monomer, that is, trimellitic acid, trimesic acid, pyromellitic acid, pentaerythritol, trimethylolpropane, or the like may be used. In the present invention, any of the thermoplastic polyesters produced by polycondensation using the compound as a monomer component as described above can be used as the component (A) of the present invention, and may be used alone or as a mixture of two or more. But
Preferably, polyalkylene terephthalate, more preferably, polybutylene terephthalate and a copolymer based on this are used.

[0005] Next, in the present invention, the (A) component organic halogen-based flame retardant blended with the thermoplastic polyester resin may be any organic halogen compound generally used as a thermoplastic polyester flame retardant. In particular, an aromatic bromine compound is preferable, and specific examples include a low-molecular-weight bromine compound such as a 5- to 10-bromine-substituted diphenyl ether compound, a low-molecular-weight organic halogen compound of tetrabromobisphenol A, and a halogenated polycarbonate ( For example, it can be obtained by reacting a brominated bisphenol A as a raw material with a polycarbonate oligomer, a halogenated epoxy compound (for example, a diepoxy compound produced by a reaction between a brominated bisphenol A and epichlorohydrin, or a reaction between a brominated phenol and epichlorohydrin). Monoepoxy compound), brominated polystyrene, brominated bisimide compound (for example, lower alkylenebistetrabromophthalimide) and the like.
Further, one or more organic halogen-based flame retardants may be used in combination. As the addition amount of the organic halogen-based flame retardant (B) increases, the mechanical properties of the composition decrease as the addition amount increases.
The amount is preferably as small as possible, but is generally from 1 to 30% by weight, particularly preferably from 3 to 25% by weight, based on the total amount of the composition. In the present invention, it is preferable to use a flame retardant auxiliary. Examples of the flame retardant auxiliary used here include metal oxides and hydroxides such as antimony trioxide, antimony tetroxide, antimony pentoxide, antimony halide, aluminum hydroxide, magnesium hydroxide and tin dioxide.
The amount of the flame retardant aid added is 0 to 15% by weight based on the total amount of the composition,
Preferably it is 1 to 10% by weight.

Next, a feature of the composition of the present invention is that the composition further comprises polytetrafluoroethylene (C) obtained by a suspension polymerization method. The basic feature of the polytetrafluoroethylene used in the present invention is that it is not produced by a conventionally used emulsion polymerization method but is obtained by a suspension polymerization method. This achieves the intended purpose. In general, polytetrafluoroethylene is polymerized by emulsion polymerization, suspension polymerization, or bulk polymerization. However, from many experimental results, it is obvious that the emulsion polymer is not intact (primary particles), but is also aggregated into secondary particles, Even with granules of any size, the improvement was minimal. On the other hand, it was recognized that the suspension polymer did not have its disadvantages surprisingly and its effect was basically different. Although the cause is not clear, since the emulsion polymer has a primary particle diameter of 1 μm or less after polymerization, no matter how agglomerated and secondarily large particles are generated, the disadvantages as primary particles occur. In general, a suspension polymer has a primary particle size of 200 μm or more. Even if the primary particle is pulverized, the particle size is 1 μm or more. It is presumed to do. In the case of a suspension polymer, primary particles after polymerization are once pulverized to 1 to 50 μm,
Granules of 10-1000μ showed particularly favorable results. In any case, in the process of preparing the composition by a simple equipment and method generally used by using a suspension polymer, agglomeration, adhesion in a pipe, a mixer, a screw feeder, a hopper, etc. It was confirmed that clogging and surging at the time of extrusion were remarkably improved, and problems such as variation in the quality of the composition and occurrence of defective products were also improved, which further contributed to improvement in physical properties. In addition, the bulk polymer is not a preferable method due to the polymerization method itself, poor heat removal, and the like. The polytetrafluoroethylene obtained by the suspension polymerization method (C) used for this purpose is commercially available or can be produced by a known method. That is, suspension polymerization of tetrafluoroethylene is carried out in an aqueous medium in the presence of an inorganic or organic peroxide in a temperature range of about 0 to 150 ° C. and a pressure of about 3 to 1000 atm without substantially using an emulsifier. Is done. In the polytetrafluoroethylene produced by this method, the primary particles immediately after polymerization have an average particle diameter of 200 to 3000 μm, and even if this is pulverized, the primary particles of the emulsion polymer (1 μm or less) as described above.
Are basically different in particle size. In the present invention, as long as it is a suspension polymer, the polymer can be used as it is, or any particle size obtained by pulverization can be used and is effective. Preference is given to using granules of 10-1000 μm, particularly about 100-800 μm, which have been subjected to agglomeration after grinding. Such preferred polytetrafluoroethylenes are commercially available such as Hoechst's Hostaflon TF1620, TF1640, Mitsui DuPont Fluorochemicals' Teflon 800-J, Teflon 82
0-J etc. The amount of the component (C) used in the present invention is 0.05 to 5% by weight, preferably 0.1 to 3% by weight of the total amount of the composition.
% By weight. (C) If the amount of the component is too small, the flame retardancy becomes insufficient in relation to the other components, and the improvement of the drip property in the combustion test in accordance with UL94 is not sufficiently improved. Inviting is not preferred.

Next, the inorganic filler (D) used in the present invention is not an essential component, but has properties such as mechanical strength, heat resistance, dimensional stability (deformation resistance, warpage), and electrical properties. In order to obtain a molded article excellent in quality, it is preferable to use a fibrous, powdery or plate-like filler depending on the purpose. As the fibrous filler, glass fiber,
Asbestos fiber, carbon fiber, silica fiber, silica
Inorganic fibrous substances such as alumina fibers, zirconia fibers, boron nitride fibers, silicon nitride fibers, boron fibers, potassium titanate fibers, and metal fibrous materials such as stainless steel, aluminum, titanium, copper, and brass. Particularly typical fibrous fillers are glass fibers or carbon fibers. High-melting organic fibrous substances such as polyamide and acrylic resin can be used in the same manner as the inorganic fibrous filler. On the other hand, powdery fillers include carbon black, silica, quartz powder, glass beads, glass powder, calcium silicate, aluminum silicate, kaolin, talc, clay, diatomaceous earth, silicates such as wollastonite, and iron oxide. Oxides of metals such as titanium oxide, zinc oxide and alumina; carbonates of metals such as calcium carbonate and magnesium carbonate; sulfates of metals such as calcium sulfate and barium sulfate; and other silicon carbide, silicon nitride, boron nitride, various types Metal powder and the like. Examples of the plate-like filler include mica, glass flake, various metal foils, and the like. In particular, fillers mainly composed of glass fibers, glass beads, glass flakes and the like are general and suitable. These inorganic fillers can be used alone or in combination of two or more.
The combined use of a fibrous filler, particularly a glass fiber or a carbon fiber, and a granular and / or plate-like filler is a preferable combination, particularly in terms of having both mechanical strength, dimensional accuracy, electrical properties and the like. When using these fillers, it is desirable to use a sizing agent or a surface treatment agent if necessary. This example is a functional compound such as an epoxy compound or an isocyanate compound. These compounds may be used after being subjected to a surface treatment or a convergence treatment, or may be added at the same time as the preparation of the material. In the present invention, such an inorganic filler
The amount of (D) is 1 to 60% by weight, preferably 5 to 50% by weight, based on the total amount of the composition. If the amount of the inorganic filler is more than 60% by weight, molding becomes difficult, and there is a problem in the mechanical strength of the molded product. The amount of the functional surface treating agent used in combination is 0 to 10% by weight, preferably 0.05 to 5% by weight, based on the inorganic filler.

Further, a small amount of a thermoplastic resin can be used in combination with the composition of the present invention. For example, ethylene-acrylic ester copolymer, polyamide, polyacetal, polystyrene, styrene-butadiene copolymer, styrene-butadiene-acrylonitrile copolymer, styrene-butadiene-acrylic acid (or ester thereof) copolymer, styrene- Acrylonitrile copolymer, polycarbonate, polyurethane, polyphenylene oxide, polyphenylene sulfide, polybutadiene, halogenated polyolefin, polyvinyl halide, butyl rubber, multi-layer graft copolymer mainly composed of polyacrylate, etc. are blended at any ratio according to the purpose. It is also possible.

In order to further impart desired properties to the composition of the present invention, known substances generally added to thermoplastic resins and thermosetting resins, such as antioxidants and heat stabilizers, ultraviolet rays Stabilizers such as absorbents, antistatic agents,
Of course, a lubricant, a release agent, a coloring agent such as a dye or a pigment, a lubricant, a plasticizer, a crystallization accelerator, a crystal nucleating agent, and the like can be blended.

The composition of the present invention can be easily prepared by known equipment and methods generally used as a conventional method for preparing a resin composition as described above. For example, i) a method of mixing each component, kneading and extruding with an extruder to prepare pellets, and then molding, ii) once preparing pellets having a different composition, mixing a predetermined amount of the pellets and molding. Any method can be used, such as a method of obtaining a molded article of a desired composition after the application and molding, and iii) a method of directly charging one or more of each component to a molding machine. Mixing and adding a part of the resin component as a fine powder with other components is a preferable method for uniformly blending these components.

[0011]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples. In addition, the measuring method of the characteristic evaluation shown in the following examples is as follows. Extrusion processing test (remarks at the time of preparing the composition pellets) ○ Mixability After mixing the various components in a rocking mixer for about 20 minutes, the mixed state (dispersion state of polytetrafluoroethylene) was visually observed. ○ Extrudability Extrusion is performed using a twin-screw extruder equipped with a 30 mm inner diameter vent equipped with a screw feeder (for quantitative feed of raw materials, additives, etc.), and feed conditions to the extruder (polytetrafluoroethylene screw feeder and hopper) The adhesion and clogging of the extruder), the state of biting, and the state after leaving the extruder (strand breakage, surging phenomenon), etc. were evaluated by visual observation in a total of five levels. Tensile test According to ASTM D 638 Flammability test (UL-94) Subject 94 of Underwriters Laboratories
According to the method of (UL-94), flammability and dripping characteristics during burning of the resin were tested using five test pieces (thickness: 1/32 inch). Examples 1 to 7 and Comparative Examples 1 to 4 Table 1 shows polybutylene terephthalate (A) having an intrinsic viscosity of 1.0.
Various halogen-based flame retardants (B), flame retardant aids, and polytetrafluoroethylene (C) produced by suspension polymerization
Was added and mixed at a ratio shown in Table 1 using a rocking mixer, and a pellet-shaped composition was obtained with an extruder. Next, a test piece was prepared by injection molding using the pellet, and the mechanical properties and the flammability were evaluated. Table 1 shows the results. For comparison, the same test and evaluation were carried out using polytetrafluoroethylene (C ′) produced by an emulsion polymerization method not belonging to the requirements of the present application. The results are shown in Table 1.

Examples 8 to 11 and Comparative Examples 5 to 9 Table 2 shows the relationship between polybutylene terephthalate (A) having an intrinsic viscosity of 0.8.
Various halogen-based flame retardants (B), flame-retardant aids, inorganic fillers (D) and polytetrafluoroethylene (C) produced by the suspension polymerization method shown in Table 2 were added and mixed in the proportions shown in Table 2, Evaluation of mechanical properties and flammability was performed in the same manner as in Example 1. Table 2 shows the results. On the other hand, using a polytetrafluoroethylene emulsion polymer (C ′) as a comparative example, the same test and evaluation were performed. The results are shown in Table 2.

[0013]

[Table 1]

[0014]

[Table 2]

*) C-1: Hostaflon TF, manufactured by Hoechst
1740 Average particle size about 40μ (Primary polymer pulverized) C-2: manufactured by Hoechst, Hostaflon TF1400 Average particle size about 400μ (Primary polymer pulverized) C-3: manufactured by Hoechst, Hostaflon TF1640 Average particle size about 400μ (C C'-1: DuPont, Teflon 6-J average particle size of about 300μ (secondary coagulation) C'-2: Hoechst, Hostaflon TF2021 average particle size of about 400μ (secondary coagulation)

[0016]

As is apparent from the above description and Examples, the present invention is a blend of a polyester resin composition containing an organic halogen-based flame retardant and a polytetrafluoroethylene having a particle diameter of 10 to 1000 μ obtained by a suspension polymerization method. The composition of the invention comprises a conventional polytetrafluoroethylene (emulsion polymer)
The various problems during the preparation of the pellets, namely, adhesion due to agglomeration of polytetrafluoroethylene, clogging and poor extrusion, etc. are remarkably improved as compared with the composition using, so that the productivity is remarkably improved and the quality is improved. A stable resin composition was obtained. In addition, the obtained composition is excellent in flame retardancy, tensile strength and elongation, etc., and is particularly suitably used for electrical parts (connectors, switches, relays, etc.) requiring Vo.

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Claims (5)

[Claims] 1. A thermoplastic polyester resin comprising (B) an organic halogen-based flame retardant in an amount of 1 to 30% by weight (in the composition), and (C) a polytetrafluoroethylene having a particle size of 10 to 1000 .mu.m obtained by a suspension polymerization method. A flame-retardant polyester resin composition containing 0.05 to 5% by weight of fluoroethylene (in the composition). 2. A flame-retardant polyester resin composition comprising the composition according to claim 1 and 1 to 60% by weight (in the composition) of one or more inorganic fillers (D). 3. The flame-retardant polyester resin composition according to claim 2, wherein (D) the inorganic filler is mainly composed of at least one selected from glass fibers, glass beads and glass flakes. 4. The flame-retardant polyester resin composition according to claim 1, wherein (A) the thermoplastic polyester resin is a polybutylene terephthalate resin, or a copolyester or a mixed polymer mainly composed of the same. Stuff. 5. The method of preparing a composition according to claim 1, wherein said composition is suspension-polymerized polytetrafluoroethylene (C).
A method of preparing a flame-retardant polyester resin composition, which is added, mixed, and kneaded as it is, or once pulverized, or agglomerated and granulated with a particle diameter of 10 to 1000 μm.