JP3320567B2 - Flame retardant polyester resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame-retardant polyester resin composition. More specifically, the present invention relates to a polyester resin composition having good friction and wear characteristics with metals and other resins without impairing excellent mechanical properties and flame retardancy, and suitable for sliding members such as bearings.

[0002]

2. Description of the Related Art Polyester resins are excellent in mechanical strength, electrical properties and other physical and chemical properties as crystalline thermoplastic resins. It is used in a wide range of applications such as automobiles and electric / electronic devices.
However, the required characteristics in such a field are gradually becoming more sophisticated, and as one example, further improvement in sliding characteristics is desired. For example, bearings for metal shafts, such as paper feed parts for printers and facsimile machines, are often provided with grease in the past because of problems such as abrasion and squeaking noise. In some cases, cutting may occur and performance may deteriorate. Therefore, there is a high demand for a material having good sliding characteristics without using grease. These components often require flame retardancy and sufficient mechanical strength due to their structure. For flame retardancy, flame retardancy is achieved mainly by adding a halogen-based flame retardant, optionally together with antimony trioxide. Further, an inorganic filler is added to improve the strength. However, since the inorganic filler and the flame retardant deteriorate the sliding properties, improvement has been desired.

[0003]

Means for Solving the Problems In view of the above problems, the present inventors have intensively studied to obtain a material having excellent slidability. As a result, a composition comprising a thermoplastic polyester as a main component, and a specific copolymer, a halogen-containing organic flame retardant, an inorganic flame retardant auxiliary treated with a specific surface treatment agent, and a fibrous filler compounded therein, It has flame retardancy and good thermal stability, and at the extrusion and molding temperature of polyester resin, almost no decomposition gas or evaporating gas is emitted, so the friction coefficient and the mechanical properties and fluidity are not greatly reduced. The present inventors have found that the wear characteristics can be greatly improved, and have reached the present invention. That is, the present invention relates to (A) a thermoplastic polyester resin, (B) 5 to 95% by weight of an ethylene-unsaturated carboxylic acid alkyl ester copolymer part and 95 to 5% by weight of a vinyl (based) copolymer part. 1 to 30% by weight (in the total composition) of a graft copolymer with
(C) 1-30% by weight of a halogen-containing organic flame retardant (in the entire composition), (D) 0.5-5% by weight (in an inorganic flame retardant) of an inorganic flame retardant treated with a coupling agent. 1-20% by weight
(In all compositions), and (E) 5 to 70% by weight of fibrous filler
(Of all compositions) is a flame-retardant polyester resin composition.

Hereinafter, the constituent components of the resin material of the present invention will be described in detail. First, the thermoplastic polyester resin (A) as the base resin of 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 these three-component compounds. , Homopolyester,
The effect of the present invention can be applied to any of the copolyesters.
Illustrative examples of dicarboxylic acid compounds constituting the thermoplastic polyester resin used here include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylethanedicarboxylic acid, cyclohexanedicarboxylic acid, adipic acid, Known dicarboxylic acids such as 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. Next, examples of the dihydroxy compound constituting the polyester (A) of the present invention include ethylene glycol, propylene glycol, butanediol, neopentyl glycol, hydroquinone, resorcin, dihydroxyphenyl, naphthalene diol, dihydroxydiphenyl ether, cyclohexanediol, 2 , 2-Bis (4-
(Hydroxyphenyl) propane, dihydroxy compounds such as diethoxylated bisphenol A, polyoxyalkylene glycols and their alkyl, alkoxy or halogen-substituted products, and one or more kinds thereof 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 more of these compounds are used. In addition, polyesters having a branched or cross-linked 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. In the present invention, those obtained by modifying the thermoplastic polyester by a known method such as crosslinking or graft polymerization may be used.

Next, the graft copolymer used as the component (B) in the present invention includes (a) 5-95% by weight of an alkyl ester copolymer of ethylene-unsaturated carboxylic acid and (b) vinyl (based). It is a graft copolymer with a copolymer portion of 95 to 5% by weight. Specific examples of the alkyl ester copolymer (a) include ethylene / acrylic acid copolymer, ethylene / methacrylic acid copolymer, ethylene / acrylic acid / ethyl acrylate copolymer, and ethylene / ethyl acrylate copolymer. And random copolymers such as ethylene / vinyl acetate copolymer and ethylene / vinyl acetate / ethyl acrylate copolymer. These alkyl ester copolymers can be used even if they are mixed. On the other hand, the (a) vinyl (based) copolymer to be graft-copolymerized with the (a) alkyl ester copolymer includes, for example, poly (methyl methacrylate), poly (ethyl acrylate), poly (butyl acrylate), and poly (acrylic acid-2) Examples include ethylhexyl, polystyrene, polyacrylonitrile, acrylonitrile-styrene copolymer, copolymer of butyl acrylate and methyl methacrylate, and copolymer of butyl acrylate and styrene. The component (B), which is a feature of the present invention, is not an alkyl ester copolymer or a vinyl (co) polymer used alone, but a copolymer of (a) and (co) of (b). The polymer has a characteristic in that it is a graft copolymer having a branched or cross-linked structure chemically bonded at at least one point, and simply having (a) or
A remarkable effect which cannot be obtained by the single combination of (b) is obtained. Here, the ratio of (a) to (b) for constituting the graft copolymer of the component (B) needs to be 5:95 to 95: 5 (weight ratio).

The graft copolymer of the component (B) used in the present invention may be produced by any of the well-known methods such as a chain transfer method and an ionizing radiation irradiation method. The grafting precursor obtained by copolymerizing the monomer of component (b) and the radical (co) polymerizable organic peroxide in the chain component particles is melt-kneaded to obtain a grafting reaction between the polymers. Things. The reason for this is that the grafting efficiency is high and secondary aggregation due to heat does not occur, so that the expression of performance is more effective. The component (B) is blended in an amount of 1 to 30% by weight (based on the total composition) based on the thermoplastic polyester resin of the component (A).
If the amount of the component (B) is too small, the effect of improving the friction and wear characteristics aimed at by the present invention cannot be obtained. If the amount is too large, the heat distortion temperature is lowered and sufficient mechanical strength cannot be obtained, which is not preferable.

The halogen-containing organic flame retardant (C) used in the present invention may be any organic halogen compound generally used as a flame retardant for thermoplastic polyesters. Examples include halogenated diphenyl ethers, halogenated aromatic bisimide compounds, halogenated aromatic epoxy compounds, low molecular weight organic halides of bisphenol A, halogenated polycarbonates, halogenated benzyl acrylates, and halogenated polystyrenes. Here, the halogen is generally preferably bromo. The flame retardant is one or two.
You may mix and use more than one kind. The object of the present invention can be achieved by using any of the above flame retardants, but in particular, halogenated aromatic bisimide compounds, halogenated aromatic epoxy compounds, halogenated diphenyl compounds, halogenated polycarbonates, halogenated benzyl acrylates The use of is preferred. Among them, a halogenated aromatic bisimide compound or a halogenated aromatic epoxy compound is preferable. Here, the halogenated aromatic bisimide compound is represented by the following general formula (1), wherein R ₁ is a divalent organic group, and is generally an alkylene group, an arylene group, and the like. Desirable are lower alkylene groups.
Also, X is at least one or more halogens, advantageously halogen atoms comprise at least 25% by weight of the molecule, preferably bromo.

[0008]

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Suitable halogenated aromatic bisimide compounds include lower alkylene bistetrabromophthalimide, especially N, N'-ethylenebistetrabromophthalimide. The halogenated aromatic epoxy compound which is a preferred flame retardant among the components (C) is represented by the following general formula:
(2) a bisphenol A type epoxy compound represented by the formula, wherein X is at least one halogen,
R ₂ represents a hydrogen atom or a glycidyl group, and n is a number of 2 or more. The preferred average degree of polymerization n is from 2 to 30, more preferably from 10 to 20.

[0010]

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[0011] The halogenated aromatic epoxy compound is
For example, halogenated bisphenol A alone or in combination with bisphenol A, if necessary, and condensed with epichlorohydrin, to halogenated bisphenol A diglycidyl ether, and further to halogenated bisphenol A alone or bisphenol A A
Can be obtained by heating to 80 to 250 ° C. in the presence of a catalyst. The content of the component (C) is from 1 to 30.
% By weight (in all compositions). An excessively large amount is not preferable because it impairs mechanical and physical properties, thermal stability and the like, and impairs the appearance of the resin. If the amount is too small, the flame retardancy becomes insufficient.

Next, the component (D) used in the present invention is an inorganic flame retardant aid treated with a coupling agent. A typical inorganic flame retardant aid is antimony trioxide. , Antimony tetroxide, antimony pentoxide, sodium pyroantimonate, tin dioxide, aluminum hydroxide,
Metal oxides such as magnesium hydroxide and hydroxides. As the coupling agent used as a surface treatment agent for the flame retardant aid, any of known silane-based, titanate-based, and aluminum-based coupling agents can be used. As the silane coupling agent used in the present invention, γ-chloropropyltrimethoxysilane, γ-chloropropylmethyldichlorosilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropylmethyldiethoxysilane,
Vinyl trichlorosilane, vinyl triacetoxy silane, vinyl triethoxy silane, vinyl trimethoxy silane, vinyl tris (β-methoxy ethoxy) silane, γ-methacryloxy propyl trimethoxy silane,
γ-methacryloxypropylmethyldimethoxysilane,
β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-mercaptopropyl Trimethoxysilane, amino-functional silane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-β- (aminoethyl)- γ-aminopropylmethyldimethoxysilane, γ- (polyethyleneamino) propyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, γ-
There are ureidopropyltriethoxysilane, methylaminoethoxypropyldialkoxysilane, N'-vinylbenzyl-N-trimethoxysilylpropylethylenediamine and the like. Next, titanate coupling agents used in the present invention include isopropyl triisostearoyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate, isopropyl tri (N-aminoethyl-aminoethyl) titanate, tetraoctylbis (ditridecylphosphonate) Phyto) titanate, tetra (2,2-diallyloxymethyl-1-butyl) bis (ditridecyl) phosphite titanate, bis (dioctylpyrophosphate) oxyacetate titanate,
Bis (dioctyl pyrophosphate) ethylene titanate, isopropyl trioctanoyl titanate, isopropyl dimethacryl isostearyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl isostearyl diacryl titanate, isopropyl tri (dioctyl phosphate) titanate, isopropyl tricumyl phenyl titanate,
And tetraisopropylbis (dioctylphosphite) titanate. Next, examples of the aluminum-based coupling agent used in the present invention include acetoalkoxyaluminum diisopropylate. These coupling agents are added in an amount of 0.5 to 5% by weight based on the inorganic flame retardant aid. The surface treatment of the inorganic flame-retardant aid which is the component (D) of the present invention can be easily prepared by equipment and a method generally used as a conventional inorganic surface treatment method. For example, 1) a method of surface-treating an inorganic flame-retardant auxiliary and a coupling agent at a high speed with a super mixer having shear force, a Henschel mixer or the like, 2) in water or in a solvent such as an alcohol or an aromatic. Surface treatment method, 3) after mixing the components of the present invention, such as a method of performing a surface treatment in a single or twin screw extruder,
Either can be used. In the present invention, (D) the use of an inorganic flame-retardant auxiliary treated with a coupling agent to improve the adhesion to polyester, and as a result, a flame-retardant polyester composition having good wear characteristics Can be obtained. The amount of the specific flame retardant aid (D) used in the present invention is 1 to 30% by weight (in the whole composition), preferably 3 to 30% by weight.
~ 15% by weight.

Next, the fibrous filler of the component (E) used in the present invention is necessary for ensuring sufficient mechanical strength, and is made of glass fiber, asbestos fiber, carbon fiber, silica fiber, silica-alumina. Inorganic fibrous substances such as 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-point organic fibrous substances such as polyamide, fluororesin, and acrylic resin can be used in the same manner as the inorganic fibrous filler. These fibrous fillers may be treated with a sizing agent or a surface treatment agent. As such a sizing agent or surface treatment agent, for example, an epoxy compound, an isocyanate compound, a silane compound,
Functional compounds such as titanate compounds. The amount of the fibrous filler (E) used is 5 to 70% by weight (in the whole composition), preferably 10 to 40% by weight.

The flame-retardant resin composition of the present invention may optionally contain a small amount of another thermoplastic resin in addition to the above components, depending on the purpose. Any other thermoplastic resin may be used as long as it is stable at high temperatures. For example, polyamide, polycarbonate, polyphenylene sulfide, polyphenylene oxide, polyacetal, polysulfone, polyethersulfone, polyetherimide, polyetherketone, fluororesin and the like can be mentioned. These thermoplastic resins can be used as a mixture of two or more kinds. Further, the flame-retardant resin composition of the present invention may be a known substance generally added to a thermoplastic resin and a thermosetting resin in order to impart desired properties according to the purpose, that is, an antioxidant or an ultraviolet absorbing agent. Stabilizers, antistatic agents,
Colorants such as dyes and pigments, lubricants, crystallization accelerators, nucleating agents, and the like can be blended.

The flame-retardant resin composition of the present invention can be easily prepared by equipment and methods generally used as conventional resin composition preparation methods. For example, 1) after mixing the components, kneading and extruding with a single-screw or twin-screw extruder to prepare pellets, and then preparing the pellets, 2) once preparing pellets having a different composition, and disposing the pellets. A method of obtaining a molded article of a target composition after molding by subjecting to quantitative mixing and molding,
3) Any method such as a method of directly charging one or more of each component to a molding machine can be used. 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.

[0016]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. Examples 1 to 7 As component (A), polybutylene terephthalate (PBT),
(B) Ethylene-ethyl acrylate copolymer 70 as a component
Graft copolymer (E / EA-g-BA / MMA) of 30% by weight of methyl methacrylate-butyl acrylate copolymer, or 70% by weight of ethylene-ethyl acrylate copolymer and 30% by weight of polystyrene % Of graft copolymer (E / EA-g-PS),
A mixture is prepared by mixing a flame retardant as component (C), a flame-retardant aid (antimony trioxide) having a surface treatment as component (D), and glass fiber (diameter 10μ) as component (E) in the proportions shown in Table 1. Then, the mixture was melt-kneaded at 260 ° C. using a 30 mmφ extruder and extruded into pellets. The surface treatment of the component (D) to the flame retardant aid was carried out by preparing a mixture of the flame retardant aid and 1.0% by weight of the coupling agent shown in Table 1, and blending the mixture with a Henschel mixer. Next, test pieces were prepared by injection molding using the pellets and evaluated.
Evaluation items and evaluation methods are as follows.・ Sliding characteristics Using a Suzuki-type friction / wear tester (contact area 2.0cm ² ), 10
A test of steel (S55C) was performed at kgf / cm ² × 300 cm / sec × 24 hours, and the dynamic friction coefficient and the specific wear amount were measured. -Flammability test (UL-94) Subject 94 of Underwriters Laboratories
The test was performed using a 5-year test piece (thickness: 1/32 inch) according to the method of (UL94). Comparative Examples 1 to 7 For comparison, as shown in Table 1, when only polybutylene terephthalate of component (A) was used (Comparative Example 1), only polybutylene terephthalate of component (A) and glass fiber of component (E) were used. In the case (Comparative Example 2), when no surface treatment was applied to the flame retardant aid (Comparative Example 3), when the graft copolymer of the component (B) was not used (Comparative Example 4), the component (B) When ethylene-ethyl acrylate copolymer (E / EA), methyl methacrylate-butyl acrylate copolymer (BA / MMA), and polystyrene (PS) were used instead of the graft copolymer (Comparative Example) 5 to 7) were evaluated in the same manner as in the above example.
Table 1 shows the results. As is evident from the results in Table 1, a flame-retardant polyester resin composition having extremely good sliding properties can be obtained by adding a surface-treated flame retardant aid and a specific graft copolymer.

[0017]

[Table 1]

Note) Flame retardant (1); brominated epoxy compound flame retardant (2); ethylene tetrabromophthalimide flame retardant auxiliary (1); antimony trioxide surface-treated with γ-aminopropyltriethoxysilane flame retardant Auxiliary agent (2); Antimony trioxide surface treated with isopropyl triisostearoyl titanate Flame retardant auxiliary agent (3); Antimony trioxide surface treated with acetoalkoxyaluminum diisopropylate Flame retardant auxiliary agent (4); Surface treatment Not antimony trioxide

[0019]

As described above, the flame-retardant polyester composition according to the present invention has excellent sliding properties and is suitable for sliding members of various OA equipments.

Claims (5)

(57) [Claims] (1) 5% to 95% by weight of (B) an alkyl ester copolymer of ethylene-unsaturated carboxylic acid and 95% by weight of a vinyl (based) copolymer, based on (A) a thermoplastic polyester resin.
(C) 1 to 30% by weight (in the whole composition) of a halogen-containing organic flame retardant, and (D) 0.5 to 5% by weight. 1 to 20% by weight (in all compositions) of an inorganic flame-retardant aid treated with a coupling agent (relative to inorganic flame-retardant aid), and (E) 5 to 70% by weight of fibrous filler (total A flame-retardant polyester resin composition comprising 2. The flame-retardant polyester resin composition according to claim 1, wherein the thermoplastic polyester resin as the component (A) is a resin mainly composed of polybutylene terephthalate. 3. The halogen-containing organic flame retardant of component (C) is selected from halogenated aromatic bisimide compounds, halogenated polycarbonates, halogenated aromatic epoxy compounds, halogenated diphenyl compounds and halogenated benzyl acrylates. The flame-retardant polyester resin composition according to claim 1. 4. The flame-retardant polyester resin composition according to claim 1, wherein the inorganic flame-retardant aid constituting the component (D) is antimony trioxide. 5. The method according to claim 1, wherein the coupling agent constituting the component (D) is selected from a silane coupling agent, a titanate coupling agent and an aluminum coupling agent. The flame-retardant polyester resin composition according to the above.