JPH1060271A - Resin composition for wristwatch part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a readily moldable and processable resin composition, having a high strength and a high elasticity and capable of imparting high reliability as wristwatch parts thereto by blending an aromatic polyamide resin with whiskers in a specific proportion. SOLUTION: This resin composition for wristwatch parts is obtained by blending 25-90 pts.wt., preferably 40-60 pts.wt. aromatic polyamide resin such as poly(m-phenylene isophthalamide), poly(p-phenylene terephthalamide) or copoly(p-phenylene/3,4-diphenyloxyterephthalamide) with 10-75 pts.wt. preferably 60-40 pts.wt. whiskers such as aluminum borate whiskers. The resin composition is capable of improving environmental resistance and watertightness of the wristwatch parts.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition used for a wristwatch component, and more particularly to a resin composition for a wristwatch component having high strength and high elasticity.

[0002]

2. Description of the Related Art A wide variety of resin materials are used in wristwatch parts such as wristwatch cases, base plates, gears, etc., mainly in the low-priced field, because of their excellent workability, corrosion resistance and low cost. Have been. In recent years, material development has progressed, and ABS resins, PPS resins, and the like have been used for lightweight watch cases. JP-A-60-245668 discloses a resin composition for a watch case in which a polyamide resin is blended with a reinforcing short fiber and metal powder. Further, JP-A-61-91254 discloses an aromatic resin composition. A resin composition for a watch case excellent in high specific gravity and high strength in which a tungsten powder, carbon fiber, glass fiber, and zinc stearate are blended with a polyamide resin is disclosed.

[0003]

However, among these resin compositions, ABS resin, PPS resin and the like are used in a wide variety of inexpensive watch cases, base plates and other wristwatch parts, but have high strength and high elasticity. Is not available,
Due to distortion of the watch case due to external force, the adhesion holding force with the cover glass is weak, especially for high-performance diver watches etc., which require high airtightness and environmental resistance, etc. Is currently the mainstream.

Japanese Patent Laid-Open No. 60-245668, 6
The polyamide resin composition described in 1-91254 has a high specific gravity and has a feeling of weight because it has a high specific gravity, and is suitable for a watch case. It was difficult to use for precision parts such as gears and for all watch parts.

An object of the present invention is to provide a resin composition for a wristwatch component which is excellent in reliability in any environment and can be used as a main component of a wristwatch by dramatically improving the strength and rigidity of a resin molded product. Is to do.

[0006]

In view of such circumstances, the present inventors have conducted repeated studies and studies, and as a result, by blending 25 to 90 parts by weight of an aromatic polyamide resin and 10 to 75 parts by weight of whiskers, The present inventors have found that a wristwatch component excellent in high strength and high elasticity can be obtained, and completed the present invention.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the practice of the present invention, by using aluminum borate whiskers as whiskers, a wristwatch component having higher strength and higher elasticity can be obtained.

[0008] The aromatic polyamide resin used in the practice of the present invention is generally synthesized from a combination of an aromatic diamine and an aromatic dicarboxylic acid chloride by a low-temperature solution polycondensation or an improved interface method. Examples are polymetaphenylene isophthallaside, polyparaphenylene terephthalamide, copolyparaphenylene / 3,4-diphenyloxyterephthalamide,
Various grades available on the market can be used alone or in combination. However, a polyamide containing meta-xylene diamine as a main component is not included because a desired high-strength material cannot be obtained.

In the practice of the present invention, the mixing ratio of each component in the resin composition for wristwatch parts is 25 to 90 parts by weight of an aromatic polyamide resin and 10 to 10 parts by weight of a whisker.
75 parts by weight.
It is preferable to use ウ ィ 60 parts by weight and whisker in an amount of 40６０60 parts by weight. When the compounding ratio of each of these components is out of the above range and the compounding amount of the aromatic polyamide resin is large, a high-strength, high-elasticity watch part cannot be obtained. The moldability of the composition deteriorates.

In the practice of the present invention, stabilizers such as antioxidants, ultraviolet absorbers, lubricant plasticizers, crystal nucleating agents and the like can be used to the extent that the performance of the wristwatch parts is not reduced.
By using a fluorine-based resin such as PTFE as a friction and wear improver, further performance can be added.

The mixing and kneading of the components of the resin composition of the present invention can be carried out according to known methods. For example, after mixing using a mixer such as a ribbon blender, a tumbler mixer, and a Henschel mixer, the mixture may be melt-kneaded, or may be mixed and kneaded simultaneously using a Banbury mixer, a screw kneader, or the like. A pellet is produced by kneading, and a molded article can be produced using the pellet by various molding methods, usually an injection molding method.

[0012] Wristwatch parts to which the resin composition for a wristwatch of the present invention can be used include a wristwatch case, a base plate, a gear, and the like [Materials Practical Encyclopedia (January 1993, Nikkei BP)
P. 258-269].

[0013]

EXAMPLES Hereinafter, the present invention will be specifically described based on examples and comparative examples. In addition, the raw materials used in Examples and Comparative Examples are as follows. Aromatic polyamide resin [manufactured by Teijin Amoko Engineering Plastics, trade name "Amodel A-10"
02 "] Polyphenylene sulfide resin (manufactured by Toprene, trade name" T-4 ") MXD polyamide 6 resin (manufactured by Mitsubishi Engineering-Plastics Corporation, trade name" Renny 6002 ") Aluminum borate whisker (manufactured by Shikoku Chemicals, trade name" Albolex " ”, True specific gravity 2.93, diameter 0.5-1
μm, length 10 to 30 μm] potassium titanate whisker (trade name “Tismo”, manufactured by Otsuka Chemical Co., Ltd., true specific gravity 3.30, diameter 0.1 to 1.5 μm, length 10 to 100 μm) glass fiber (manufactured by Nitto Boseki) , Trade name "CS3PE454
S ", true specific gravity 2.54, diameter 13 µm, length 3 mm]

[Examples 1 to 3] The aromatic polyamide resin was kneaded using a twin screw extruder [TEM-35, manufactured by Toshiba Machine Co., Ltd.], and aluminum borate whiskers or potassium titanate whiskers were fed by side feed. It was charged and melt-extruded at 320 ° C. to pelletize. Using an injection molding machine having a mold clamping pressure of 30 tons, the thus obtained pellets were used to produce test pieces, a watch case, and a wristwatch component of the main plate.

For the test piece, a bending test (ASTM)
D-790), specific gravity measurement (ASTM D-792)
), And a physical property test of high strength and high elasticity was performed. The wristwatch case and the base plate, which are wristwatch parts, were actually assembled in a wristwatch, and subjected to an environmental resistance test in which the temperature was changed and a performance test by a submersion test assuming a depth of 200 m. In addition, these test results were as shown in Table 1.

[Comparative Examples 1 to 3] Aluminum borate whiskers were blended with polyphenylene sulfide resin (hereinafter, referred to as PPS resin) or MXD polyamide 6 resin (hereinafter, referred to as MXD-6 resin).
Upon molding and evaluation, the results were as shown in Table 1.

Comparative Example 4 Glass fibers were blended with an aromatic polyamide resin and extruded, molded and evaluated in the same manner as in the examples. The results are as shown in Table 1.

Examples 1 to 3 and Comparative Examples 1 to 3 all have good moldability and high rigidity, but the performance tends to decrease as the amount of whiskers decreases. The resin composition in which aluminum borate whiskers were mixed with the PPS resin or the MXD-6 resin of Comparative Examples 1 to 3 was considered to be water droplets in the wristwatch case in the environmental resistance test and the water immersion test, possibly due to deformation due to insufficient strength. Clouding has occurred. The resin composition in which the aromatic polyamide resin of Comparative Example 4 was mixed with glass fiber had high strength, but due to insufficient rigidity, fogging similar to Comparative Examples 1 to 3 occurred in an environmental resistance test and a submergence test.

The molded article made of the aromatic polyamide resin in the examples maintains high strength and high rigidity, and the wristwatch incorporating the wristwatch component made of the resin composition of the present invention has no fogging due to water droplets in the performance test. It was confirmed that highly reliable wristwatch parts could be obtained.

[0020]

[Table 1]

[0021]

According to the resin composition for a wristwatch component of the present invention, the ease of molding is maintained, and the obtained wristwatch component has remarkably high strength and high elasticity as compared with conventional products. High reliability can be provided as a part.

Claims (2)

[Claims] 1. A resin composition for a wristwatch component comprising 25 to 90 parts by weight of an aromatic polyamide resin and 10 to 75 parts by weight of a whisker. 2. The resin composition for a wristwatch component according to claim 1, wherein an aluminum borate whisker is used as the whisker.