JP2000281884A - Polybutylene terephthalate resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition having excellent sliding property by including polybutylene terephthalate, a specific polytetrafluoroethylene polymer and a filler. SOLUTION: This composition is obtained by adding (A) 100 pts.wt. of polybutylene terephthalate resin with (B) 3-50 pts.wt. of polytetrafluoroethylene polymer having <=50 μm average particle diameter (e.g. a tetrafluoroethylene copolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, a tetrafluoroethylene-perfluoroalkoxyethylene copolymer or the like) and (C) 10-100 pts.wt. of a filler, e.g. potassium titanate fibers, mica, talc, wollastonite or the like and blending. The composition is suitable to a site required to sliding property such as a chassis, a tray or a pickup base as an OA device, an information recording medium device or a resin internal mechanism member of a home electronic device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to polybutylene having excellent slidability obtained by blending (A) a polybutylene terephthalate resin with (B) a polytetrafluoroethylene polymer having a specific particle size and (C) a filler. The present invention relates to a terephthalate resin composition.

[0002]

2. Description of the Related Art It is widely known that a polytetrafluoroethylene polymer and a filler are added to a polybutylene terephthalate resin to improve the slidability. , Copiers, printers, faxes, communication equipment and DVDs and CDs
-Chassis, tray, pickup base, guide rail as resin internal mechanism parts for information storage media devices using ROM, FD, HD, LD, MD, etc. as information media, and home appliances such as game machines, music players, AV devices, etc. , Gears and the like. However, ordinary polytetrafluoroethylene polymers are insufficiently dispersed in the actual polybutylene terephthalate resin, and in many cases, cannot meet the strict requirements for sliding characteristics in recent years.

[0003]

In view of such circumstances, the present inventors have conducted intensive studies to obtain a polybutylene terephthalate resin composition having excellent sliding properties, and as a result, selected and used a specific polytetrafluoroethylene polymer. Was found to be extremely effective, and the present invention was completed. That is, the present invention relates to (A) 100 parts by weight of a polybutylene terephthalate resin, (B) 3 to 50 parts by weight of a polytetrafluoroethylene polymer having an average particle size of 50 μm or less, and
(C) It relates to a polybutylene terephthalate resin composition obtained by adding and blending 10 to 100 parts by weight of a filler.

[0004]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the components of the resin material of the present invention will be described in detail. First, the polybutylene terephthalate resin (A), which is a base resin of the resin material of the present invention, is polybutylene obtained by polycondensing terephthalic acid or an ester-forming derivative thereof and an alkylene glycol having 4 carbon atoms or an ester-forming derivative thereof. Terephthalate. Polybutylene terephthalate is itself
It may be a copolymer containing 70% by weight or more. As dibasic acid components other than terephthalic acid and its lower alcohol esters, aliphatic and aromatic polybasic acids such as isophthalic acid, naphthalenedicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, and succinic acid or ester-forming derivatives thereof And the like, as a glycol component other than 1,4-butanediol, ordinary alkylene glycols such as ethylene glycol, diethylene glycol, propylene glycol, trimethylene glycol, hexamethylene glycol, neopentyl glycol, cyclohexane dimethanol, and the like. Lower alkylene glycol such as 3-octanediol, bisphenol A, 4,4 '
Aromatic alcohols such as dihydroxybiphenyl, alkylene oxide adducts such as ethylene oxide 2 mol adduct of bisphenol A and propylene oxide 3 mol adduct of bisphenol A, glycerin,
Examples include polyhydroxy compounds such as pentaerythritol or ester-forming derivatives thereof. In the present invention,
Any of polybutylene terephthalate formed by polycondensation using the above compound as a monomer component can be used as the component (A) of the present invention.
It is used by mixing more than one kind. Further, the intrinsic viscosity of the polybutylene terephthalate resin used is not particularly limited, but o-chlorophenol as a solvent,
The concentration is preferably 0.5 dl / g or less at 25 ° C. at 0.5% by weight. This is for the purpose of improving the adhesion to the mold at the time of molding to improve the friction characteristics, and improving the flow characteristics.

Next, in the present invention, (B) a polytetrafluoroethylene polymer is used, the average particle size of which is 50 μm.
m, more preferably 30 μm
m or less. By specifying the particle size (average particle size), the dispersibility in the resin is improved, and the friction and wear resistance characteristics are improved. If the particle size exceeds 50 μm, sufficient friction and wear resistance characteristics are obtained. I can't. The (B) polytetrafluoroethylene polymer used is added in an amount of 3 to 50 parts by weight, preferably 5 to 30 parts by weight, based on 100 parts by weight of the (A) polybutylene terephthalate. If the addition amount is too small, sufficient sliding characteristics cannot be obtained,
On the other hand, if it is excessively large, the mechanical properties inherent in polybutylene terephthalate are impaired and the moldability is problematic, so that it is practically difficult to use. The method for producing the polytetrafluoroethylene polymer is not particularly limited, but is preferably a pulverized coagulated product obtained by suspension polymerization. After suspension polymerization, the pulverized product has a narrow particle distribution and no agglomerates, and is uniformly dispersed in the resin. on the other hand,
The polytetrafluoroethylene polymer obtained by the emulsion polymerization has agglomerates and a wide particle distribution, and the dispersion in the resin is not uniform as compared with the suspension polymerization product. The polytetrafluoroethylene polymer in the present invention includes not only a tetrafluoroethylene polymer, but also a tetrafluoroethylene-hexafluoropropylene copolymer, a tetrafluoroethylene-perfluoroalkoxyethylene copolymer, and a trifluoride polymer. An ethylene copolymer, an ethylene tetrafluoride-ethylene copolymer and the like are also included.

In the present invention, a filler (C) is used. Such fillers need to be blended in order to obtain excellent properties such as mechanical strength, heat resistance, dimensional stability, and electrical properties, and are particularly effective for increasing rigidity. For this purpose, a fibrous, powdery or plate-like filler is used depending on the purpose. As the fibrous filler, glass fiber, asbestos fiber, carbon fiber, silica fiber,
Silica / alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate fiber,
Further, fibrous materials of metals such as stainless steel, aluminum, titanium, copper, brass and the like can be mentioned. Incidentally, a high melting point organic fibrous substance such as polyamide and acrylic resin can also be used. Examples of the particulate filler include carbon black, quartz powder, glass beads, glass powder, silicates such as calcium silicate, aluminum silicate, kaolin, talc, clay, diatomaceous earth, and wollastonite, iron oxide, and oxide. Titanium, oxides of metals such as alumina, calcium carbonate,
Examples thereof include metal carbonates such as magnesium carbonate, metal sulfates such as calcium sulfate and barium sulfate, silicon carbide, silicon nitride, boron nitride, and various metal powders. Examples of the plate-like inorganic filler include mica, glass flake, various metal foils, and the like. The type of the filler is not particularly limited, and one or more fillers may be added, but it is particularly preferable to use potassium titanate fiber, mica, talc, and wollastonite. (C)
The filler is added and blended in an amount of 10 to 100 parts by weight, preferably 20 to 70 parts by weight, per 100 parts by weight of the polybutylene terephthalate resin (A). If it is too small, sufficient rigidity cannot be obtained,
When added in excess, the moldability is poor and the toughness is reduced.

Further, the composition of the present invention may be used in combination with known substances generally added to thermoplastic resins and the like in order to impart desired properties according to the purpose.
For example, a stabilizer such as an antioxidant, an ultraviolet absorber, a light stabilizer, a flame retardant, a flame retardant auxiliary, an antistatic agent, a lubricant, a release agent, a coloring agent such as a dye or a pigment, a plasticizer, and the like are mixed. It is possible. In particular, the addition of an antioxidant for improving heat resistance is effective.

[0008] The polybutylene terephthalate resin composition of the present invention can be easily prepared by equipment and methods generally used as a conventional resin composition preparation method. For example, (1) a predetermined amount of components constituting the composition of the present invention are mixed at once and melt-kneaded by a single-screw or twin-screw extruder to obtain pellets of a desired composition. (2) Two raw material inlets are provided. With a single-screw or twin-screw extruder having the above, a resin, a stabilizer, a pigment component, etc. are charged and melt-kneaded from a first input port, and then an inorganic filler is charged from a second material input port, and melt-kneaded. To obtain pellets having a desired composition. Also,
Grinding a polybutylene terephthalate resin in powder form in advance and adding a polytetrafluoroethylene polymer powder thereto is an effective method for improving the dispersion of the polytetrafluoroethylene polymer in the polybutylene terephthalate resin.

The method for molding the resin composition of the present invention is not particularly limited, such as injection molding, extrusion molding, blow molding, etc., but injection molding is particularly preferred.

[0010] The polybutylene terephthalate resin composition of the present invention exhibits high sliding properties and, in addition to the heat resistance of the polybutylene terephthalate resin, provides a copier, a printer, a fax, a communication device, a DVD, a CD-ROM,
An information storage medium device using an FD, HD, LD, MD or the like as an information medium, and a chassis as a resin-made internal mechanical part of a home appliance such as a game machine, a music player, or an AV device;
It is particularly suitable for parts requiring slidability, such as trays, pickup bases, guide rails, and gears.

[0011]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples. Examples 1 to 6 As shown in Table 1, (A-1) a polybutylene terephthalate resin (PBT) having an intrinsic viscosity of 0.61 dl / g, (B-1) an average particle diameter of 13 μm, and polytetrafluoroethylene by suspension polymerization. The sliding properties of the polymer (PTFE) (Fluon L169J, manufactured by Asahi ICI Fluoropolymer Co., Ltd.) and (C-1) potassium titanate fiber or (C-2) mica were evaluated as follows. Comparative Examples 1-3 When no polytetrafluoroethylene polymer was added, or when polytetrafluoroethylene polymer (P
The TFE was evaluated in the same manner as in the above example except that (B'-1) an average particle size of 470 μm and a product obtained by emulsion polymerization (Sanflon SG3000 manufactured by Kitamura Co., Ltd.) were used.

<Sliding property against steel> A test piece made of AL5056 and a test piece made of a test material were slid with a thrust type sliding tester, and the dynamic friction coefficient and the specific wear amount were evaluated.・ Sliding condition testing machine Thrust type friction and wear testing machine (manufactured by Orientec Co., Ltd.) Surface pressure 0.49MPa Linear velocity 30cm / sec Sliding for 24 hours

[0013]

[Table 1]

[0014]

As described above, the polybutylene terephthalate resin composition of the present invention exhibits excellent sliding properties in addition to the excellent mechanical properties inherent in polybutylene terephthalate. , Printer, fax, communication equipment, DVD, CD-ROM, FD, HD, L
Information storage media devices used as information media such as D and MD,
In addition, it is particularly suitable for parts requiring slidability such as chassis, trays, pickup bases, guide rails, and gears as resin-made internal mechanical parts of home appliances such as game machines, music players, and AV equipment.

Claims (4)

[Claims] (1) Polybutylene terephthalate resin (A) 100
A polybutylene terephthalate resin composition comprising (B) 3 to 50 parts by weight of a polytetrafluoroethylene polymer having an average particle diameter of 50 μm or less and (C) 10 to 100 parts by weight of a filler, based on parts by weight. 2. The polybutylene terephthalate resin composition according to claim 1, wherein the filler (C) is at least one selected from potassium titanate fibers, mica, wollastonite and talc. 3. A resin, internal mechanical component of an OA device, an information storage medium device, or a household electrical appliance formed by molding the resin composition according to claim 1 or 2, such as a chassis, a tray, a pickup base, a guide rail, and a gear. Molded products used for sliding members that require high heat resistance. 4. An OA device such as a copying machine, a printer and a facsimile, a communication device, a DVD, a CD-ROM, an FD, an HD and an L formed by molding the resin composition according to claim 1 or 2.
An information storage medium device using D, MD, etc. as an information medium;
And molded articles used as resin-made internal mechanism parts for home appliances such as game machines, music players, AV equipment, and the like.