JPH0364365A - Structural member of timepiece - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a timepiece component using a resin composition in which a thermoplastic resin is reinforced with vapor grown carbon fibers.

[Conventional technology]

Traditionally, watch components used WC-Co as exterior parts.
Recently, practical research using powdered SUS and powdered Ti is known. Furthermore, as a watch component whose basic composition is a thermoplastic resin that has excellent mechanical strength, wear resistance, chemical resistance, and thermal properties, for example, Japanese Patent Publication No. 55-45576 discloses glass fiber or metal fiber. discloses a high-strength watch component in which a thermoplastic resin is filled with metal powder or the like.

[Problem to be solved by the invention]

Watch components manufactured using conventional powder molding and sintering are
Although high hardness (HV1300) can be obtained, which cannot be easily obtained using ordinary metals such as carbide cases, there are very large restrictions on the degree of freedom in terms of design. In addition, materials using powdered SUS or powdered Ti, which have recently been studied for practical use, have reached 98% of the theoretical density through forming processing using the HIP method, but it is still necessary to eliminate voids and uneven filling. However, if the surface of the watch component is polished, countless pits will appear, making it impossible to obtain the metallic luster and corrosion resistance required for the component, and furthermore, the design freedom during molding will be limited. It has many drawbacks, such as very large restrictions, and has not been put into practical use.

Furthermore, the thermoplastic resin is filled with glass fibers, metal fibers, metal powder, etc. to obtain high strength, but if the molecular weight of the thermoplastic resin is large, the fluidity of the resin will be poor and the surface texture will be poor. In order to improve fluidity, fluidity is improved by selecting a resin with a low molecular weight or adding a lubricant, but even though the fluidity is improved, resin compositions that have been improved in this way do not cause paris during injection molding. mechanical strength is also reduced. Furthermore, the method of improving fluidity by adding a metal with a high specific gravity such as tungsten poses a practical problem since high specific gravity metal powder such as tungsten is an extremely expensive metal powder.

In order to solve these problems, the present invention uses a high molecular weight thermoplastic resin to produce vapor grown carbon fiber (hereinafter referred to as VC).
To provide a composition for a watch component, which can be highly filled with metal powder (abbreviated as CF), has high strength and fluidity, has a clean surface, and can produce a component with high commercial value at a low cost. With the goal.

[Means to solve the problem]

The present inventors have previously discovered VGC as a new carbon material.
We were conducting basic research on the development of GCF and the properties and reactivity of this material, and in fact, we focused on the unique morphology, mechanical properties, chemical and thermal stability, and light resistance of this GCF, and developed various types of GCF. During practical tests, we found that this VCCF not only has an excellent shape and agglomeration state, but also has excellent dispersion into other substances.■The GCF-containing resin composition also has improved dimensional stability and weather resistance, and is a low-warping material. The present invention was achieved by discovering that it is suitable as a component for a watch.

The present invention uses a thermoplastic resin of 20 to 70% by weight and a fiber diameter of 0.
01-4.0 μm vapor grown carbon fiber 5-50% by weight
This is a timepiece component, characterized in that it is made of a resin composition containing 0 to 30% by weight of metal powder.

In the present invention, VCCF is a fibrous carbonaceous material produced by heating a carbon source such as a hydrocarbon in the presence of a catalyst and growing it in a vapor phase. When you observe it in a mirror, you can see the core and the surrounding area.
When you look at it, you can see fibers with a unique shape made up of tree-ring-like carbon layers.

In the present invention, VGCF refers to fiber diameter of 0.01 to
4 Brn, preferably 0.01 to 2 ptm, particularly preferably 0.01 to 0.05 ptm, and the length of the fiber is not particularly limited. The length of the fiber is generally 500
It is less than 0μI, but it can be even shorter <toooμm
100, 1/11, or 1.0 am, and fibrous materials obtained by crushing or cutting these into shorter lengths, or pulverized granular or irregularly shaped materials may also be used.

VC; CF of the present invention has high carbon purity, generally 97
．． It is 5% or more. In addition, in the present invention, VCCF is
In structural analysis by X-ray analysis, those whose lattice constant Co is in the range of 7.1θ to 6.88 are particularly preferably used.

The composition ratio of VCCF in the watch component in the present invention is 5.
~50% by weight, preferably 10-40% by weight, particularly preferably 10-35% by weight.

If it is less than 5% by weight, the mechanical properties will not improve, and if it is more than 70% by weight, the mechanical properties will be improved, but it will take a long time to improve the dispersion state, which is disadvantageous in terms of cost, and the fluidity will deteriorate, making it difficult to mold. Impairs workability.

In the present invention, the thermoplastic resin is preferably a polyamide resin such as nylon 6 or nylon 66, a polyester resin such as a polyacetal resin, a polyethylene terephthalate, a polycarbonate resin, or an ABS resin with a high molecular weight. Low molecular weight materials have low Vickers hardness and are not suitable for watch components. Among thermoplastic resins, polyamide resins with excellent mechanical properties are preferred, and nylon 66
Resin is preferable, and even nylon 66 resin has a molecular weight of 15i0.
A value in the range of 00 to 45,000 is used. Preferably, the molecular weight is in the range of 20,000 to 40,000, most preferably in the range of 25,000 to 35,000. Those with a molecular weight of 15,000 or less have excellent fluidity, but their mechanical strength does not reach the required physical properties and their Vickers hardness is low, making them unsuitable for watch components. Moreover, the molecular weight is 45.
Nylon 66 resin having a high molecular weight of 000 or more has excellent mechanical properties, but is disadvantageous in that it has poor fluidity and is difficult to injection mold.

The composition ratio of the thermoplastic resin in the present invention is 20 to 70% by weight, preferably 30 to 601% by weight, particularly preferably 35 to 60% by weight.

In the present invention, metal powder has a particle size of 1.0 to 300.
Stainless steel, iron, copper, etc. with a diameter of μm are preferable, and the composition ratio is 0 to 30% by weight, preferably 0 to 25% by weight, and particularly preferably 0 to 20% by weight.

In the composition for a watch component of the present invention, various known compounding agents such as an M chloride agent, a stabilizer, an antioxidant, a lubricant, and an additive for improving mold releasability from a mold during molding are used. May contain.

When producing the composition for watch components of the present invention, first,
Blend the resin, real VGCF, and metal powder to ensure uniform dispersion. The blending method may be tri-blending, wet blending, or impregnation blending, and is not particularly limited.

Triblend uses a stirrer such as a Henschel mixer, and the stirring time and rotation speed are arbitrarily set so that the resin powder, GC, F, and metal powder are uniformly mixed. On this occasion,
It is effective to use resin powder with a particle size of 1 mm or less. In addition, in wet blending, first, a liquid that does not dissolve the resin, such as water or alcohol, is placed in a stirrable container, and VCCF and metal powder are added thereto and stirred to form a slurry.

Next, a predetermined amount of a desired type of resin powder is added to this slurry, and further. Stir. This slurry is then filtered and dried. Furthermore, the impregnated blend is prepared by mixing and stirring the resin, VCCF, and metal powder, which have been separately dissolved in a solvent in advance, and then removing the solvent and drying. For melt-kneading thermoplastic resins, a kneader such as a Banbury mixer, kneader, roll mill, or screw extruder can be used. In this way, by melt-kneading the pre-blended composition, it is possible to obtain a uniformly dispersed composition for a timepiece component.

In this melt-kneading process, it is common to first form a pellet-like product and then use it for molding. The composition thus obtained can be used to manufacture timepiece components of desired sizes by injection molding. Further, it is formed into a sheet-like or film-like intermediate product by an extrusion molding method, a calendar molding method, or the like, and then manufactured as a watch component by a vacuum molding method or the like.

The watch components manufactured in this way have a high-class image. VCCF is acicular and has a fine fiber diameter of 0.01 to 4 μm, making it difficult for fibers and fiber ends to protrude on the surface of the component, and prevent protrusion into the surface layer, which is a problem with resin components such as PAN-CF and glass fiber. It has excellent surface smoothness and feels good to the touch. Also, VCCF
is a watch component that is also a conductive material that prevents the generation of static electricity and is resistant to stains.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

In addition, each characteristic value in Examples and Comparative Examples was measured according to the following method or JIS5 standard.

Tensile strength JIS K-6810 bending strength
JIS K-6810 Bending elastic modulus JIS K-6810 bits hardness; determined by the following method using a Pickers hardness tester (Akashi Seisakusho type).

Test load when indenting the test surface using a diamond square pyramid indenter with a facing angle of 136 degrees (0.3 kgf)
It was calculated from the diagonal length of the depression (calculated from the surface area of the depression!!)

Test load 0.3 kgf Holding time 15 seconds θ F = Load (0.3 kgf) S = <Surface area of depression rmz d = <Length of diagonal of depression θ; Face angle of diamond indenter Example 1 Fiber diameter 0.05-0.5 μm VGCF () Lisacetylacetonatoiron and benzene were introduced into a heating space at 1300°C and synthesized in a suspended state, with a carbon content of 99% or more and a lattice constant Co of 7.02). A VCCF was obtained which was slightly crushed, easy to disperse, and whose fiber length was substantially 5 μm or more when observed under an electron microscope.

250 g of this VGCF and 650 g of nylon 66 resin (Leona, registered trademark) type 1500 (manufactured by Asahi Kasei Industries, Ltd.), molecular weight 32.500, which was cold-pulverized and adjusted to an average particle size of 50 μm, were mixed for 5 minutes in a Henschel mixer. 100 g of stainless metal powder with an average particle size of 80 μm was added to the dispersed composition, and the resulting composition was mixed and dispersed for 2 minutes using a Henschel mixer, and the resulting composition was turned into a belent using an Ikegai Iron Works WPCM30 twin-screw extruder. The pellet was further dried at a temperature of 120°C under pressure for 8 hours, and then injection molded using an injection molding machine (KC-20 manufactured by Yoro Iron Works) at an injection temperature of 320"C and a mold temperature of 85°C to form a test piece. were prepared and various physical properties were measured.The results are shown in Table 1.

Example 2 A test piece was prepared in the same manner as in Example 1, except that the blending amounts were changed to 350 g of VGCF, 550 g of nylon 66 resin, and 100 g of stainless metal powder, and the physical properties were evaluated. The results are shown in Table 1.

Example 3 A test piece was prepared in the same manner as in Example 1, except that the blending amounts were changed to 450 g of VC; 550 g of nylon 66 resin, and the physical properties were evaluated. The results are shown in Table 1.

Comparative Example 1 Nylon 66 resin (Leonataive 1 used in Example 1)
A test piece was prepared using the method of Example 1 only for 500), and the physical properties were evaluated. The results are shown in Table 1.

Comparative Example 2 Glass fiber (fiber diameter 9 μm, fiber: Ift length 3 mm
), 550 g of nylon 66 resin, and 100 g of stainless metal powder were used to prepare a test piece in the same manner as in Example 1, and its physical properties were evaluated. The results are shown in Table 1.

From the results in Table 1, the mechanical properties of the test piece made with the VGCF mixed composition are improved by several steps in tensile strength, bending strength, and bending modulus compared to Comparative Example 1, which is made only of nylon resin. Further, a comparison between Example 2 and a test piece prepared using a composition containing 35% by weight of glass fiber reveals that the VCCFCC reciprocal resin composition has superior mechanical properties and Pickers hardness.

Table 1 [Effects of the Invention] The timepiece component of the present invention maintains a decorative appearance and has the effect of reducing weight by synthetic resin molding. Furthermore, the surface is clean and the texture is reinforced by VGCF, making it possible to perform fine injection molding not only on the exterior parts of watches, but also on interior parts, such as gear shafts. In addition, VGCF's conductivity prevents static electricity, which is effective not only in preventing dirt on watches but also during watch manufacturing and assembly, making it the most suitable material in terms of cost.

Claims (1)

[Claims] 1. Thermoplastic resin 20-70% by weight, fiber diameter 0.01-
A timepiece component comprising a resin composition comprising 5 to 50% by weight of 4 μm vapor-grown carbon fiber and 0 to 30% by weight of metal powder.