JPH0948914A - Molded gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-durability high-strength molded gear having high dedendum strength, not producing any noise, the so-called juddering, produced from rubbing between the meshed teeth even when used under nonlubricated conditions and scarcely suffers from any wear even under greased conditions. SOLUTION: This molded gear is made of a composition prepared by reinforcing 100 pts.wt. polyamide 12 having a number - average molecular weigth (Mn) of (2-4)×10<4> or a mixture thereof with a specified amount of a polyamide 12 having an Mn of (1-2)×10<4> with 5-40 pts.wt. PAN-derived carbon fiber. Alternatively, this gear is made of a composition prepared by reinforcing 100pts.wt. polyamide 12 having a melt viscosity (η) of (2-8)×10<3> P at 230 deg.C or a mixture thereof with a specified amount of a polyamide 12 having an η of (0.8-2)×10<3> P with 5-40 pts.wt. PAN-derived carbon fiber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyamide resin composite material composed of a polyamide resin and carbon fiber and having good gear characteristics, and is used in the fields of automobile-related equipment, electronic / electrical equipment, and general industry. The present invention relates to improvement of resin gears used in the field of mechanical parts and the like.

[0002]

2. Description of the Related Art Conventional resin gears for the above fields are lighter in weight, more self-lubricating, are corrosion resistant, and have a lower noise level than metal gears.
Since it has characteristics such as mass productivity, it can be easily used in various fields instead of metal. Examples of the resin material include polyacetal and polyamide resin from the viewpoint of mechanical properties and sliding characteristics. Particularly, the resin composition containing the former as a main component is
Since it has relatively excellent gear load characteristics and high productivity, it is often used as a resin material for gears.

However, in recent years, as a demand for resin gears, so-called higher load, that is, higher tooth root strength, and low noise and low frictional noise while maintaining low wear even in non-lubricated specifications, are so-called. There is a demand for long-life products with excellent sliding characteristics that do not cause "squeaking", and existing materials are no longer able to handle them.

[0004]

In the case of a conventional resin gear, for example, a polyacetal resin (abbreviated as POM), its simple substance or a composition for filling a reinforcing material with glass fiber or carbon fiber and the like is loaded without lubrication. When the conditions become strict, noise due to meshing friction of gears, a so-called "squealing" phenomenon occurs, friction of tooth surfaces becomes large, and gear life is shortened.

Further, when the POM resin is used under a lubricating condition in which grease is initially applied, the wear of the composition filled with carbon fiber as a reinforcing material is larger than that of the non-lubricated specification. At this time, even if the grease is not special, the phenomenon of increased wear generally occurs in the case of silicon-based, lithium-based, and fluorine-based as well, and the higher the adjustment of the grease, the greater the wear amount in a short period of time. There is.

Other resin gears such as polyamide (PA
Abbreviated), PA6, PA66, PA46, etc. are known. However, as a general characteristic of polyamide-based resins, a phenomenon of mechanical property deterioration over time due to water absorption (wet) occurs, and with this, gear wheels It also shortens the life. When these PA resins are filled with a reinforcing material and used as a reinforcing composition, "squealing" occurs when the load condition becomes severe under unlubricated condition, as in the case of polyacetal gears.
Under the lubrication condition by applying grease, the wear increases more than under non-lubrication condition under the same condition.

PA12 has a drawback that it is generally softer than other polyamide resins, and was not suitable for mechanically high load applications. However, due to its softness, PA12 is conventionally used as a single body ( Articles used as sound-deadening gears as unfilled materials containing no fibers (for example, "Recent plastic molded gears";"Plastic" magazine, VOL. 4)
1・ No7, p55, published by Industrial Research Society). However, because of its low strength and elastic modulus, it was considered unsuitable for use under high load conditions.

Further, a composition containing a solid lubricant such as molybdenum disulfide, graphite, or tetrafluoroethylene, or an oil-containing composition has an advantage of being able to prevent the occurrence of "squeaking" in the absence of lubrication. It is not suitable for use under high load conditions because it has the drawback that the mechanical properties of the product are lower than the base polymer alone.

For such high load applications, Japanese Patent Application No. 3-155253 and Japanese Patent Application Laid-Open No. 5-3940 by the present inventors.
There is a previous proposal to use a composition as shown in No. 5. That is, Japanese Patent Application No. 3-152553 proposes a gear composition containing a thermoplastic polyether aromatic ketone as a matrix and a pitch-based carbon fiber as a reinforcing material. Further, Japanese Patent Application No. 3-217862 proposes a gear composition comprising a polyacetal resin as a matrix, an aromatic polyamide fiber as a reinforcing material, and a tetrafluoroethylene resin as a lubricity imparting material.

However, even with these, it becomes insufficient to meet the demands in the further advanced industrial fields, in particular, the requirements for low wear, low noise and high root strength (high load), and the material cost is high. There was a flaw.

[0011]

[Means for Solving the Problems] In response to the more advanced industrial demands as described above, the conventional technique is not sufficient, the tooth root strength is high, and the decrease in strength due to water absorption is small. A material for gear molded products that has low wear in the non-lubricated specification, does not cause "squeaking" due to gear mesh friction, and does not increase wear in the lubricated (initial application of grease) specification, and can meet a wide range of advanced requirements. Various studies were conducted on the compounding recipe.

As a result, 1) a polyamide resin having excellent sliding characteristics was selected, and among them, a general drawback of this type of PA resin was that the decrease in mechanical strength due to water absorption (wetness) was particularly small. Taking advantage of the characteristics of polyamide 12, this was selected as the base polymer. 2) However, in order to compensate for the drawback that this base polymer is soft and lacks in strength, 3) a specific type of carbon fiber is added as a reinforcing material, 3) a specific amount is added, 4) the molecular weight distribution of the base polymer,
Or, combined with the selection of the optimum range of melt viscosity, it can be manufactured by injection molding, has high strength and high elastic modulus, does not have "squeaking", has a small amount of wear, and has a change in performance over time due to moisture absorption. We were able to obtain the desired gear material with high durability.

Further, constituent components of the composition of the present application will be described. The polyamide 12 referred to in the present invention is a polyamide 12 [A] having a number average molecular weight (abbreviated as Mn) of (2-6) × 10 ⁴ , particularly preferably (2-4) × 10 ^4. Is. This is because a material in this range can be injection-molded in terms of fluidity and the like as a composition containing a predetermined carbon fiber (C), and can serve as a base polymer for a gear having high strength.

[0014] Alternatively, Mn is (2 to 6) × 10^Four， Good
Much better (2-4) x 10^FourPolyamide 12 [A]
And Mn is (1-2) × 10^FourPolyamide 12 [B]
And a mixture of 12 [A] and 12 [B] has a weight ratio of
Mixtures of 3 to 8 are suitable. Thus, Mn is small
By adding a small amount of low molecular weight polymer,
The flow characteristics of the composition are further improved, resulting in precision moldability and production.
The improvement in sex can be achieved.

The so-called polyamide 12 referred to here is a synthetic polymer also called as nylon 12, which is obtained by polymerizing ω-laurolactam or ω-aminododecanoic acid as a raw material monomer by a known method such as ring-opening polymerization or polycondensation. It is a compound.

The number average molecular weight (Mn) is a value obtained by expressing the average molecular weight of a synthetic polymer having a molecular weight distribution by the number average method, and is defined as follows.

[0017]

## EQU1 ## M _N = W / Σ N _i = Σ N _i
M _i / Σ N _i

Where N _{i is the} number of molecules having a molecular weight M _i ,
W: Weight of molecule of molecular weight M Specifically, it is measured by a thermodynamic or chemical method such as freezing point depression method, vapor pressure depression method, osmotic pressure method, or end group determination method. Reference: “Chemical Handbook (Applied)” page 757 [Chemical Society of Japan] Revised 3rd edition (Maruzen) “Polyethylene resin” page 46 [Plastic material course 4] Nikkan Kogyo Shimbun

The polyamide 12 resin according to the present invention is
Another different physical property, namely the melting temperature of the resin 230
It can also be specified by the melt viscosity (η) at ⁰ C and a shear rate of 1000 / sec. Even when using the polyamide 12 resin whose η measured under such conditions is within the range of (2-8) × 10 ³ poises, as in the case of the resin defined by the above Mn, the Can solve problems.

It is extremely rare for a polymer to be a monodisperse polymer composed of only a single molecular weight, and it is generally a polydisperse polymer having a certain distribution. Therefore, it is represented by an average value and is represented by a number average, a weight average, a Z average molecular weight, etc. depending on the measuring method. Therefore, when expressed by the number average method as in the present application, a certain polymer (M
When a polymer having a much lower (or higher) molecular weight than this polymer is added to n), the Mn value greatly changes depending on the compounding amount. Therefore, in the present application, the melt viscosity (η) is not defined only by the number average method (Mn).
Also defined the physical properties of the base polymer that can be injection-molded and do not impair the so-called characteristics of the present application. Mn and η are separate physical property display methods and can be independently defined. Regarding the resins used in the examples described below, the Mn display and the η display are shown together for the same resin.

For the above reason, η measured by the following method and conditions is (2 to 8) × 10 ³ poises of polyamide 12 (E) and η is (0.8 to 2) × 10 ³ poises. A polyamide 12 (F) which is
Even if a resin blend having a blending ratio of (E) / 12 (F) of 3 to 8 is used as the base polymer, the same purpose can be achieved. By blending a small amount of 12 (F) having a low melt viscosity in this way, the flow characteristics during molding are further improved, and precision moldability and productivity can be improved.

Various devices and methods for measuring the melt viscosity are known, but in the experiments of the present invention, [Flow tester; CFT-500C (manufactured by Shimadzu Corporation)] was used and the measurement was carried out under the above predetermined conditions. . An example of the device is shown in FIG.
The calculation was based on the following formula.

[0023]

## EQU00002 ## Apparent Shear Stress; τω = Pr / 2L (Pa) Apparent Shear Rate; γω = 4Q / πr ³ (sec ^-1 ) Apparent Viscosity; η = ττ / γω (Pa · s)

However, P barrel internal pressure unit (Pa) F extrusion load (N) Note. R Barrel radius (m) 1 Pa · s r Capillary radius (m) = 10 poise L Capillary length (m) Q Flow rate (m ³ / s) Cited reference: “Chemical Handbook (Applied)” page 770 [Nippon Kagaku] Association] Revised 3rd edition (Maruzen) "Flow tester instruction manual" (published by Shimadzu Corporation) The measurement results of the melt viscosity of the base polymer resin are shown in Fig. 9 and in the column for the description of the test sample after [0021]. .
As is clear from FIG. 9, the melt viscosity (η) of the resin varies depending on the temperature to be measured and the shear rate, so in the present application, the value at 230 ⁰ C and 1000 / sec is defined. did.

The so-called carbon fibers (C) in the present invention are PAN-based (polyacrylonitrile raw material) carbon fibers of various grades. As is clear from the comparison between Examples 1 and 7 and Comparative Example 7, a pitch-based fiber cannot provide a gear with sufficient performance.
There are several grades of PAN-based carbon fiber, including general-purpose products, high-strength products, and high-elasticity products, depending on the manufacturing method. If the adhesion between polyamide and fiber is at the same level, these grades will be used. The effect on the gear load characteristics is not so different.
(Fig. 6) From the above experimental results, the reinforcing fiber (C) to be placed on the above base polymer is limited to PAN-based carbon fiber, except for the custom-made products that require special performance. From the viewpoint of economy, general-purpose grade PAN-based carbon fiber, which can be obtained at a relatively low price among PAN-based, is preferable.

The amount of carbon fiber to be added to the base polymer is preferably 5 to 40 parts with respect to 100 parts by weight of the polymer. When the amount is 5 parts or less, the reinforcing effect is little expressed, and when the amount is 40 parts or more, the melt viscosity is too large, which makes injection molding difficult. or,
The texture of the tooth surface is not good.

In the composition of the present invention, in addition to the above main components, that is, polyamide 12 (A) or (A + B) or polyamide 12 (E) or (E + F) and PAN-based carbon fiber (C), a polymer material is used. Various additives (D) generally added to the above can be added within a range that does not impair the characteristics of the above resin composition. The usual additives are heat stabilizers,
Antioxidants, weather resistance stabilizers, release agents, lubricants, plasticizers, lubricants, dyes and pigments, antistatic agents, etc.

These main components and additives are tumblers,
Alternatively, a blended mixture obtained by mixing with a Henschel mixer or the like can be used to obtain a pellet-shaped mixture by a known uniaxial or biaxial melt-kneading extruder, and a known injection molding method to obtain a molded product.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, the present invention specifies polyamide 12 having a relatively small strength decrease due to water absorption as a base polymer, and from the viewpoint of moldability, its molecular weight (Mn) or melt viscosity. (Η) is specified to improve moldability, and is soft and excellent in sound deadening, but in order to make up for the defects of the resin inferior in strength and elasticity, PAN-based carbon fiber is specified and a specific amount thereof is blended. By combining these specific conditions, it was possible to obtain a gear molded product with high tooth root strength, low noise, low wear and high durability under both unlubricated and lubricated conditions. Hereinafter, the present invention will be specifically described with reference to Examples by way of comparison with Comparative Examples.

[0030]

[Examples 1 to 7]

[Comparative Examples 1 to 7] 1) Preparation of test sample [Example 1] Polyamide 12 (UBE Nylon 3035)
U: Ube Industries, Ltd .: Mn 3.5 × 10 ⁴ ) 100 parts by weight, PAN-based carbon fiber (Vesphite HTA-C6NR)
S: manufactured by Toho Rayon Co., Ltd .: tensile strength 3720 MPa, tensile elastic modulus 235 GPa) 30 parts by weight were mixed with a mixer to obtain injection molding pellets with a twin-screw extruder.
In addition, 12 [3035U] which is the base polymer of this example
The melting temperature 230 ⁰ C, melt viscosity at a shear rate of 1000 / sec (eta) was 5 × 10 ³ From the results of FIG. The injection pressure at the time of injection molding of a single [3035U], which will be described later in [0044], is shown in FIG. 2A as a reference example.

Example 2 A sample was prepared under the same conditions as in Example 1 except that 19 parts of carbon fiber was used in Example 1.

[Example 3] [Example 4] [Example 5] Polyamide 12 (UBE nylon 3035U: Mn3.
5 × 10 ⁴ ), Polyamide 12 (UBE Nylon 301
4U: Mn 1.4 × 10 ⁴ ) and A / B = 7.5 [example 3]: 4.7 [example 4]: 3.3 [example 5] [all are weight ratios] blended polyamide 12 , 100 parts by weight, and 30 parts by weight of the carbon fibers used in Examples 1 and 2 were mixed by a mixer to obtain pellets in the same manner. In addition, η of the polyamide 12 as the base polymer of this example under a predetermined condition is
From the result of FIG. 9, 3035U is 5 × 10 ³ , 3 respectively.
014U was 1 × 10 ³ poise.

Example 6 100 parts of polyamide 12 (UBE nylon 3024U: Mn 2.4 × 10 ⁴ ) was mixed with 30 parts of the above carbon fiber to obtain pellets in the same manner.
The base polymer of this example is 12 [3024U].
Under the predetermined conditions, η was 3.0 × 10 ³ .

Example 7 100 parts of polyamide 12 (UBE nylon 3035U: Mn 3.5 × 10 ⁴ ) was added with P
AN carbon fiber (Bethfight HM40, C6URS,
32 parts of a tensile strength of 2740 MPa and a tensile elastic modulus of 382 GPa (manufactured by Toho Rayon Co., Ltd.) were mixed to obtain pellets in the same manner.

Comparative Example 1 100 parts of polyamide 12 (UBE nylon 1014U: Mn 1.4 × 10 ⁴ ) was mixed with 30 parts of the same carbon fibers as in Example 6 to obtain pellets in the same manner. The base polymer of this example is 12 [301
4U] is 1 × 10 based on the result of FIG. 9 under a predetermined condition.
^{Was 3} .

Comparative Example 2 Commercially available polyacetal resin (P
OM / M90, made by Polyplastics Co., Ltd.
Used alone, compared with the material of the present application.

Comparative Example 3 100 parts of polyamide 6 (UBE Nylon 1030B: Mn 3.0 × 10 ⁴ ) was mixed with 27 parts of the above-mentioned carbon fiber, and pellets were similarly obtained.

[Comparative Example 4] 100 parts of polyphthalamide (Amodel A-1000HN: manufactured by Teijin Amoco) was mixed with 26 parts of the above carbon fiber to obtain pellets in the same manner.

Comparative Example 5 Polyamide 46 (TW40
0: made by Japan Synthetic Rubber) was mixed with 26 parts of the above carbon fiber to obtain pellets in the same manner.

Comparative Example 6 Leona CF300 (commercially available from Asahi Kasei), PA66 / carbon fiber material material.

[Comparative Example 7] Polyamide 12 (same as in Example 6) was mixed with pitch-based carbon fiber (Dialead K223N).
-M, tensile strength 2300 MPa, tensile elastic modulus 215 GP
a: Mitsubishi Chemical) 34 parts were mixed and pellets were obtained in the same manner.

2) Test Method Pellets were obtained from the materials and methods exemplified above, and a gear described in the following [0038] was manufactured by an injection molding method in a conventional manner. Using the power absorption type dynamic gear tester shown in Fig. 1, the load capacity and wear amount of the gears were evaluated.

The fluidity at the time of melting, which is an index of the injection moldability of the resin composition, was evaluated by the minimum injection pressure required to flow 50 mm long with a width of 20 mm × 1 mm (FIG. 2). The gear is an involute gear and is a standard gear conforming to JIS: B1701 with a module 1.0: pressure angle 20 ⁰ : number of teeth 30: tooth width 8 mm: mounting boss inner diameter 20 mm.

3) Test Results FIG. 2 shows the test results regarding the relationship between various samples and the injection (filling) pressure during injection molding. Lower pressure indicates better fluidity and easier molding. In addition, the gear load characteristics of various materials were tested by combining the above-mentioned gears of the same type with a lithium-based grease initial application specification, a rotation speed of 200 rpm, and room temperature. The results are shown in FIGS. Regarding the presence or absence of the "squealing" occurrence phenomenon, after combining the same type of gears, operating for 1 hour with no lubrication specification and no load, 20 to 1000
Evaluation was performed in the range of rpm and bending stress: 0 to 55 MPa.
The results are shown in Table 1. Regarding the tooth flank wear of gears, the same type of gear combination, lithium-based grease initial application specifications, rotation speed 2
The experiment was conducted under the conditions of a tooth root bending stress of 55 MPa at 00 rpm at room temperature, and the wear height amount of the gear surface was measured by a projector.
FIG. 7 shows the results.

FIG. 9 shows the melting temperature of the basic component resin, which is the base polymer, when the carbon fiber was not added.
Viscosity (η) when the shear rate was changed at 30 ⁰ C
Is shown. As the figure (eta) is the melting temperature, so they change the shear rate is 230 ⁰ C according to [claim], 100
It was defined as the value at 0 / sec.

4) Findings from the test results FIG. 6 shows the results of a comparative experiment in which only the type of carbon fiber was changed and the other conditions were the same. When PAN-based carbon fiber was used (Examples 1 and 7) Shows better results than the case of using pitch-based fibers (Comparative Example 7). Further, from the comparison between Example 1 (general-purpose product) and Example 7 (high-elasticity product) in this figure, PAN-based carbon fiber has a high load capacity regardless of the manufacturing process and physical properties. It was found that the resin composition for a gear having the above can be obtained. From the results of FIGS. 2 to 7 using the samples of Examples 1 to 7, the blending ratio of the carbon fiber and the base polymer is within the range of 5 to 40 parts by weight of the carbon fiber based on 100 parts by weight of the base polymer. A gear with good injection moldability, product strength, and appearance was obtained. Although not shown in the figure, the findings from the trial experiment show that the strength improvement effect is small at 5 parts or less,
It was confirmed that the moldability and the product appearance were deteriorated when the content was 40 parts or more.

The gear molded article according to the present invention (FIG. 5, Example 1) using polyamide 12 (A) or (E) having a specific Mn or η is a polyacetal (POM) under the same conditions. It is clear that it has a higher load capacity than the gear (FIG. 5 / Comparative example 2) and the gears using another type of polyamide (PA) (FIG. 5 / Comparative examples 3, 4 and 5).

Also, in the test for the occurrence of “squeaking” under non-lubricating conditions, it was confirmed that the samples of the example group having the specific conditions did not have “squeaking” under all the test conditions. A significant difference was recognized from the sample of the comparative example group not having the conditions. (Table 1)

When a small amount of polyamide 12 having a small Mn or η is blended (FIG. 2, d, e, f),
Even if carbon fiber is further mixed, the fluidity at the time of melting can be improved as compared with the case where these are not mixed (Fig. 2b, c), and as a result, the injection molding work can be made easier. It was (Fig. 2) As shown in Figs. 3 and 4 for the effect of Mn or η on the mechanical strength by adding a small amount of a small component.
As shown in, if the 12 (A) / 12 (B) ratio or the 12 (E) / 12 (F) ratio is in the range of 3 to 8,
It is almost negligible and does not substantially reduce strength,
Moreover, the compatibility effect of improving the moldability was recognized.

Gears using the polyamide 12 defined in the present invention (FIGS. 7 and Examples 1 and 2) have other polyamides such as PA6, 46, 66 as base polymers (Comparative Examples 3, 5, 6). Less wear than).

Predetermined Mn or P that is in the range of η
Gears formulated and prepared as described above using A12 are
As shown in FIG. 8, the hygroscopicity is extremely small compared to the case of using other types of polyamide resins, for example, PA6,66, and as a result, mechanical strength, bending elastic modulus, etc. are little changed with time, and the performance is stable. I was able to get the gear that I did.

[0052]

The gear molded product according to the present invention produced by the above-mentioned prescription has a higher tooth root strength than the polyacetal gears and the other types of polyamide gears which have been widely used in the past. Even with non-lubricated specifications, low noise gears that do not generate "squeal" due to meshing friction can be obtained. Also in the lubrication specification, the tooth surface wear of the gear under the initial application of grease is extremely low and durable, and its hygroscopicity is low, so that there is little change in performance over time. While having the above advantages, injection moldability,
The product appearance is also good, and it is possible to provide a new product as a gear for precision equipment in industry.

[0053]

[Table 1]

[Brief description of drawings]

FIG. 1 is a gear tester used for evaluation of test samples.

FIG. 2 is a diagram showing measurement results of flow characteristics of molten resin.

FIG. 3 is a diagram showing a relationship between PAN-based material and gear load characteristics.

FIG. 4 is a diagram showing a relationship between a compounding ratio of PA12 (B) and PA12 (C) and a root bending stress.

FIG. 5 is a diagram showing the relationship between the type of base polymer and gear load characteristics.

FIG. 6 is a diagram showing a relationship between carbon fiber types and gear characteristics.

FIG. 7 is a diagram showing a comparison test result of wear characteristics of gears according to various formulations.

FIG. 8 is a diagram showing a comparison test result of water absorption characteristics of gears according to various formulations.

FIG. 9 is a diagram showing the measurement results of the relationship between the melt viscosity of the base polymer and the shear rate.

FIG. 10 is a schematic view of an apparatus for measuring the melt viscosity of a base polymer.

[Explanation of symbols]

 1 Motor 2 V Pulley 3 Bearing Box 4 Torque Meter 5 Driving Gear 6 Driven Gear 7 Slip Ring 8 Coupling 9 Powder Clutch 11 Piston 12 Barrel 13 Capillary P Barrel Internal Pressure F Extrusion Load R Barrel Radius r Capillary Radius L Capillary Length Q Flow Late

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location B29K 309: 04 B29L 15:00 (72) Inventor Masaya Kurokawa 1-1, Tokuan, Tsurumi-ku, Osaka No.71 Starlight Industry Co., Ltd.

Claims (4)

[Claims] 1. The number average molecular weight (Mn) is (2-6) ×
10 Polyamide 12 is ⁴ (A): 100 parts by weight,
PAN-based carbon fiber (C): A gear molded product obtained by molding a resin composition comprising 5 to 40 parts by weight. 2. The number average molecular weight (Mn) is (2-6) ×
Polyamide 12 (A), which is 10 ⁴ , and Mn (1-
2) × 10 ⁴ blend with polyamide 12 (B), where the blend (weight) ratio of 12 (A) / 12 (B) is 3
Polyamide 12 (A + B) resin blend that is ~ 8: 10
A gear molded product obtained by molding a resin composition comprising 0 parts by weight and PAN-based carbon fiber (C): 5 to 40 parts by weight. Wherein the melting temperature 230 ⁰ C, shear rate 1000
Polyamide 12 (E) having a melt viscosity (η) of 2 to 8 × 10 ³ poises / sec; 100 parts by weight, P
A gear molded product obtained by molding a resin composition consisting of 5 to 40 parts by weight of AN carbon fiber (C). Wherein the melting temperature 230 ⁰ C, shear rate 1000
Polyamide 12 (E) having a melt viscosity (η) of (2 to 8) × 10 ³ poises / sec and η (0.8 to
2) A mixture with polyamide 12 (F) which is 10 ³ poises, and the compounding ratio of 12 (E) / 12 (F) is 3 to 10.
Polyamide 12 (E + F) resin blend that is 8; 100
A gear molded article obtained by molding a resin composition comprising 5 parts by weight and 5 parts by weight of PAN-based carbon fiber (C).