JPH1112459A - Polyamide resin composition and molding made therefrom - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyamide resin composition and a molding made therefrom, desirably used as a door check lever of e.g. an automobile and being excellent slidability such as frictional characteristics and abrasion characteristics. SOLUTION: This composition comprises 95-70 pts.wt. polyamide resin having a relative viscosity of 1.0-4.5 and 5-30 pts.wt. ultrahigh-molecular-weight polyolefin. This composition may further contain at most 5 pts.wt., per 100 pts.wt. composition, at least one additive selected among talc, a phosphate powder and a lubricating oil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyamide resin composition having excellent slidability such as friction characteristics and abrasion characteristics, and a molded article using the same. In particular, the present invention relates to a molded product that can be suitably used as a door check lever of an automobile or the like.

[0002]

2. Description of the Related Art Conventionally, sliding members such as gears, bearings, and cam bearings of automobiles have conventionally been made of polyamides such as nylon 6 and nylon 66 which have excellent sliding properties such as friction and wear properties and mechanical properties. Resin was used. However, like a car door check lever,
In a sliding member used under more severe conditions, it is necessary to further improve the slidability as compared with the above-mentioned polyamide resin.

FIG. 1 shows a door check lever 1 of a general automobile. 3 is a metal lever,
3a is connected to the vehicle body, and 3b is connected to the door. Reference numeral 2 denotes a resin layer integrally provided on the outside of the lever 3, which is made of a material having improved abrasion resistance and a lower coefficient of friction than the metal lever 3, such as a polyamide resin. It is formed of the added resin composition.

Specifically, a polyamide resin having a slidability improving agent added thereto, for example, a nylon 6 resin having an intrinsic viscosity of about 0.7 to 2.5 obtained by melt polymerization or melt polycondensation, There has been proposed a resin composition in which additives such as Teflon (trade name of polytetrafluoroethylene: registered trademark), a fluorine-based copolymer, and high-density polyethylene are blended. However, the resin composition containing such an additive requires a large amount of the additive to be added in order to improve the slidability. As a result, although the slidability is improved,
Since the mixing ratio of the nylon 6 resin is reduced, there is a problem that the mechanical properties and heat resistance of the resin composition are reduced. In addition, Teflon is well known as a slidability improving agent, but is generally expensive, so that there is a problem that it is difficult to mix Teflon at a high ratio in terms of cost.

Further, instead of the above, a resin composition in which a lubricant such as low molecular weight silicone oil or wax is blended with nylon 6 or nylon 66 has been proposed. However, although a resin composition containing such a lubricant can provide sufficient slidability for short-term use, a low-molecular-weight lubricant emerges on the surface of the resin composition after long-term use. Therefore, there was a problem that it could not be used stably.

As another example, a resin composition in which molybdenum disulfide, graphite or a phosphate powder is blended with a polyamide resin has been proposed, and such a resin composition is made of the above-mentioned Teflon or fluorine-based resin. As with resin compositions containing additives such as copolymers and high-density polyethylene, it is necessary to add a large amount of molybdenum disulfide, graphite, phosphate powder, etc. to obtain sufficient slidability. Therefore, there has been a problem that mechanical properties and moldability are reduced.

Japanese Patent Application Laid-Open No. 6-345961 proposes a resin composition in which wollastonite, an acid-modified styrene-based copolymer and an acid-modified high-density polyethylene are blended with a polyamide resin. However, such a resin composition has a large amount of wear and is inferior in wear characteristics.

Furthermore, Japanese Patent Application Laid-Open No. 8-157714 proposes a resin composition comprising a polyamide resin and an acid-modified high-density polyethylene having a weight average molecular weight of 50,000 to 400,000. Although such a resin composition has improved impact resistance, it has a problem that the friction coefficient is large, so that the amount of wear is large, the wear characteristics are low, and the slidability is poor.

[0009]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and provides a polyamide resin composition excellent in sliding properties such as frictional properties and abrasion properties, and a molded article using the same. It is intended to provide a molded product that can be suitably used as a door check lever for a door.

[0010]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention. That is, the present invention provides a relative viscosity of 1.0 to 4.
5. A polyamide resin composition comprising 95 to 70 parts by weight of a polyamide resin of No. 5 and 5 to 30 parts by weight of an ultrahigh molecular weight polyolefin.

According to the present invention, the relative viscosity is 1.0 to 4.5.
By blending 5 to 30 parts by weight of the ultrahigh molecular weight polyolefin with respect to 95 to 70 parts by weight of the polyamide resin composition, the coefficient of friction and the amount of wear are reduced, and the sliding property is improved.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The polyamide resin composition of the present invention has a relative viscosity of 1.0 to 4.5.
It must be composed of 0 parts by weight and 5 to 30 parts by weight of the ultrahigh molecular weight polyolefin.

The relative viscosity of the polyamide resin must be as follows. Specifically, 1.0 g of a sample was dissolved in 100 cc of this solvent using 96% sulfuric acid as a solvent, and the relative viscosity measured by a conventional method at a temperature of 25 ° C. was 1.0.
Must be ~ 4.5. If the relative viscosity is less than 1.0, a molded article excellent in slidability cannot be obtained, and the mechanical properties will be poor. On the other hand, when the relative viscosity exceeds 4.5, the moldability becomes poor.

By blending 95 to 70 parts by weight of a polyamide resin having such a relative viscosity with 5 to 30 parts by weight of an ultrahigh molecular weight polyolefin having high slidability, the slidability of the resin composition is improved. . When the compounding ratio of the polyamide resin is more than 95 parts by weight, the compounding ratio of the ultrahigh molecular weight polyolefin becomes small, resulting in inferior slidability. When the blending ratio of the polyamide resin is less than 70 parts by weight, a resin composition having poor mechanical properties is obtained.

According to the present invention, in order to further improve the slidability of the polyamide resin composition, 100 parts by weight of the polyamide resin composition is further mixed with phosphate powder, talc or lubricating oil. 5 parts by weight or less of at least one additive selected from
You may mix | blend in the ratio of 5 weight part.

[0016] Phosphate powder, talc, or lubricating oil is an additive that enhances the fluidity of the polyamide resin composition. By blending such an additive, the friction coefficient and the amount of wear of the polyamide resin composition can be reduced. It becomes smaller and slidability improves. If the compounding ratio of the additive exceeds 5 parts by weight, the fluidity becomes too high, resulting in poor moldability and poor slidability.

Examples of the molded article using such a polyamide resin composition include sliding members such as gears, bearings, cam bearings, and door check levers of automobiles. In particular, it can be suitably used as the door check lever 1 as shown in FIG.

The polyamide resin as the main component of the resin composition of the present invention includes homopolyamides and copolyamides obtained by polymerization of lactam or aminocarboxylic acid or polycondensation of diamine and carboxylic acid, and mixtures thereof. . Specific examples include homopolymers such as nylon 6, nylon 66, nylon 46, nylon 610, nylon 612, nylon 11, and nylon 12, and copolymers or mixtures containing two or more of these components. Among them, nylon 6 and nylon 66 are particularly preferred.

The ultrahigh molecular weight polyolefin which is a slidability improver is not particularly limited in shape such as powder, pellet, chopped fiber and the like, but usually has a weight average molecular weight of 1,000,000 or more and a bulk density of not less than 1,000,000. 0.94 g / cm ³
As described above, a fine powder having an average particle diameter of 100 μm or less is preferable. If the ultrahigh molecular weight polyolefin has a weight average molecular weight of less than 1,000,000, the resulting molded article will have insufficient slidability. If the bulk density is less than 0.94 g / cm ³ or the average particle size exceeds 100 μm, it is not preferable because a molded article having excellent slidability cannot be obtained.

Examples of the ultrahigh molecular weight polyolefin include ultrahigh molecular weight polyethylene, ultrahigh molecular weight polypropylene, ultrahigh molecular weight 4-methyl-1-pentene, ultrahigh molecular weight polybutene-1, and the like. Polyethylene is particularly preferred.

In the case of ultra high molecular weight polyethylene, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-
Α-olefins such as hexene, 1-octene and 1-decene; dienes such as butadiene and isoprene; cycloolefins such as cyclopentene, cyclohexene and cyclopentadiene; and acrylates such as methyl acrylate, ethyl acrylate and butyl acrylate in small amounts. It may be copolymerized.

As the talc, one of the additives, generally available ones can be used. In addition, as the phosphate, a second or third phosphate, metaphosphate, pyrophosphate, calcium phosphate, calcium phosphate-hydrogen phosphate, barium phosphate, lithium phosphate, calcium metaphosphate which is insoluble or almost insoluble in water is used. And zinc pyrophosphate and the like. Among them, particularly preferred are second and third phosphates, metaphosphates and pyrophosphates which are insoluble or almost insoluble in water.

The above phosphate is in the form of powder,
It is preferable to use a powder that can pass through the mesh.
In addition, lubricants such as spindle oils, turbine oils, machine oils, aromatic oils such as dynamo oil, naphthenic oils, paraffinic oils or hydrocarbons, esters, polyglycols, and silicone oils A commonly used lubricating oil such as oil is used.

In the polyamide resin composition of the present invention, carbon fiber, fluororesin powder, molybdenum disulfide, and the like are used in order to further improve the slidability such as friction characteristics and abrasion characteristics when molded. Additives such as glass beads may be added. In addition, if necessary, fillers such as calcium carbonate and barium sulfate, whiskers such as potassium titanate, and a conductivity improving filler such as carbon black and metal powder are added within a range that does not impair the sliding properties of the resin composition. You may. In addition, deterioration inhibitors, stabilizers, lubricants,
A plasticizer, a flame retardant, an antistatic agent, a colorant, a release agent, and the like can be appropriately added.

The method for producing the resin composition is not particularly limited, but it is preferable that the polyamide resin composition and the ultrahigh molecular weight polyolefin are blended using a twin screw extruder and pelletized. The same applies to the case where at least one selected from phosphate powder, talc, and lubricating oil is added to the resin composition.

In order to obtain a molded article from the polyamide resin composition thus obtained, an injection molding machine is used.
What is necessary is just to injection-mold the said resin composition.

[0027]

Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. In addition, the measurement of various physical-property values in an Example was measured by the following methods.

(1) Relative viscosity: 96 g of sulfuric acid was used as a solvent, and 1.0 g of a sample was dissolved in 100 cc of the solvent.

(2) Tensile strength (MPa): ASTM-D
It measured according to the method of -638.

(3) Tensile elongation (%): ASTM-D-6
The measurement was carried out according to the method described in No. 38.

(4) Flexural strength (MPa): ASTM-D
It measured according to the method of -790.

(5) Flexural modulus (GPa): ASTM-
It measured according to the method of D-790.

(6) Abrasion amount (mg · mm ² / kg · k)
m): Using resin composition, outer diameter 25.6 mm, inner diameter 2
A cylindrical test piece having a thickness of 0 mm and a thickness of 15 mm was prepared. Next, a Suzuki-type friction and wear tester (CM manufactured by Toyo Sokki Co., Ltd.)
Mold), using S45C steel as a mating material, test load 15 kgf (contact pressure 7.5 kg / cm ² ), peripheral speed 30 c
The rotation was performed under the condition of m / sec. Three hours later, the weight of the sample was measured, and the amount of wear was determined from the difference from the weight before the test. (7) Coefficient of friction: using resin composition, outer diameter 25.6 m
A cylindrical test piece having a diameter of 20 mm, an inner diameter of 20 mm, and a thickness of 15 mm was prepared. Then, using a friction force detector of a Suzuki type friction and wear tester (CM type manufactured by Toyo Sokki Co., Ltd.), the load was 7.5 kg.
The friction coefficient after 1 hour and the friction coefficient after 2 hours were measured under the condition of / cm ² .

Example 1 As a polyamide resin, 90 parts by weight of nylon 6 having a relative viscosity of 2.5 (A1030J manufactured by Unitika Ltd.) was used. The ultrahigh molecular weight polyolefin has a weight average molecular weight of 2,000,000, an average particle diameter of 30 μm, and a bulk density of 0.94 g.
10 parts by weight of ultra-high molecular weight polyethylene (Miperon XM-220 manufactured by Mitsui Petrochemical Industry Co., Ltd.) having a ratio of / cm ³ .

The blending ratio of nylon 6 and ultra high molecular weight polyethylene was blended using a twin screw extruder (Model No. PCM-30 manufactured by Ikegai Iron Works, Ltd.) set at a cylinder temperature of 260 ° C. to produce resin pellets.

The obtained resin pellets were vacuum dried at a temperature of 90 ° C. for 15 hours. Using the resin pellets, the above-described test piece was produced by an injection molding machine adjusted to a cylinder temperature of 260 ° C. and a mold temperature of 80 ° C.

Table 1 shows the measurement results of the mechanical properties, the coefficient of friction, and the amount of wear of the obtained resin composition.

[0038]

[Table 1]

Example 2 15 parts by weight of ultra-high molecular weight polyolefin (Miperon XM-220 manufactured by Mitsui Petrochemical Industries) was used for 85 parts by weight of nylon 6 (A1030J manufactured by Unitika) resin.

Other than that, a test piece was prepared in the same manner as in Example 1. Table 1 shows the measurement results of the mechanical properties, the coefficient of friction, and the amount of wear of the obtained resin composition.

Example 3 20 parts by weight of ultra-high molecular weight polyolefin (Miperon XM-220 manufactured by Mitsui Petrochemical Industries) was used for 80 parts by weight of nylon 6 (A1030J manufactured by Unitika) resin.

Other than that, a test piece was prepared in the same manner as in Example 1. Table 1 shows the measurement results of the mechanical properties, the coefficient of friction, and the amount of wear of the obtained resin composition.

Example 4 As a polyamide resin, 90 parts by weight of nylon 6 having a relative viscosity of 2.5 (A1030J manufactured by Unitika) was used. The ultrahigh molecular weight polyolefin has a weight average molecular weight of 2,000,000, an average particle diameter of 30 μm, and a bulk density of 0.94 g.
10 parts by weight of ultra-high molecular weight polyethylene (Miperon XM-220 manufactured by Mitsui Petrochemical Industry Co., Ltd.) having a ratio of / cm ³ .

Then, based on 100 parts by weight of the total of the nylon 6 and the ultrahigh molecular weight polyethylene, an ultrafine talc having a particle size of 0.9 μm (manufactured by Nippon Talc Co., Ltd.) was further added as an additive.
N (F)) was used in an amount of 0.5 part by weight.

A twin screw extruder (PCM-30, manufactured by Ikegai Iron Works Co., Ltd.) in which the mixing ratio of nylon 6, ultra high molecular weight polyethylene and talc was set at a cylinder temperature of 260 ° C.
To prepare resin pellets.

The obtained resin pellet was vacuum dried at a temperature of 90 ° C. for 15 hours. Using this resin pellet, a test piece was produced by an injection molding machine adjusted to a cylinder temperature of 260 ° C. and a mold temperature of 80 ° C.

Table 1 shows the measurement results of the mechanical properties, the coefficient of friction, and the amount of wear of the obtained resin composition.

Example 5 As an additive, 2 parts by weight of a lubricating oil (silicon oil TSF451-1M manufactured by Toshiba Silicone Co., Ltd.) was used instead of talc.

A test piece was prepared in the same manner as in Example 4 except for the above. Table 1 shows the measurement results of the mechanical properties, the coefficient of friction, and the amount of wear of the obtained resin composition.

Example 6 3 parts by weight of a phosphate powder (tricalcium phosphate manufactured by Taihei Chemical Industry Co., Ltd.) was used as an additive.

A test piece was prepared in the same manner as in Example 4 except for the above. Table 1 shows the measurement results of the mechanical properties, the coefficient of friction, and the amount of wear of the obtained resin composition.

In all of Examples 1 to 6, the polyamide resin and the ultrahigh molecular weight polyolefin were blended within the range of the present invention, and thus all of them had a good friction coefficient and a low abrasion amount and were excellent in sliding property. Met. Examples 1 to 3
Then, when the blending amount of ultra high molecular weight polyolefin increases,
Although the mechanical properties are slightly lowered due to the decrease in the blending ratio of the polyamide resin, the friction coefficient and the amount of wear are reduced, and the slidability is improved.

In each of Examples 4 to 6, the talc, the phosphate and the lubricant were added to the resin composition of Example 1, so that the mechanical strength was equal to or slightly lower than that of Example 1. However, the coefficient of friction and the amount of wear were reduced, and slidability was improved.

Comparative Example 1 The material of the resin composition was only nylon 6 having a relative viscosity of 2.5 (A1030J manufactured by Unitika). Other than that, the test piece was produced in the same manner as in Example 1.

Table 1 shows the measurement results of the mechanical properties, friction coefficient, and abrasion amount of the obtained resin composition.

Comparative Example 2 Nylon 6 having a relative viscosity of 2.5 (A103 manufactured by Unitika Ltd.)
0J) is less than the lower limit of the range of the present invention and is 65 parts by weight. Ultra high molecular weight polyethylene having a weight average molecular weight of 2,000,000, an average particle diameter of 30 μm, and a bulk density of 0.94 g / cm ³ (Miperon X manufactured by Mitsui Petrochemical Industries, Ltd.)
M-220) is greater than the upper limit of the range of the present invention.
5 parts by weight.

A test piece was prepared in the same manner as in Example 1 except for the above. Table 1 shows the measurement results of the mechanical properties, the coefficient of friction, and the amount of wear of the obtained resin composition.

Comparative Example 3 Talc was used as an additive, and its blending amount was more than the upper limit of the range of the present invention to 10 parts by weight.

A test piece was prepared in the same manner as in Example 4 except for the above. Table 1 shows the measurement results of the mechanical properties, the coefficient of friction, and the amount of wear of the obtained resin composition.

In Comparative Example 1, since only the polyamide resin was used, although the mechanical properties were excellent, the coefficient of friction and the amount of abrasion were large and the slidability was poor. Comparative Example 2
Since the compounding ratio of the polyamide resin was less than the lower limit of the present invention, the mechanical properties were inferior, and it was not suitable for use as a door check lever of an automobile.

In Comparative Example 3, since the mixing ratio of the additives was larger than the upper limit of the present invention, the friction coefficient and the amount of abrasion were large and the slidability was poor.

[0062]

According to the present invention, the relative viscosity is from 1.0 to 4.
By preparing the polyamide resin composition from 95 to 70 parts by weight of the polyamide resin No. 5 and 5 to 30 parts by weight of the ultrahigh molecular weight polyolefin, a resin composition having excellent slidability can be obtained. Further, by adding at least one kind selected from phosphate powder or talc or lubricating oil to 100 parts by weight of the polyamide resin composition in a ratio of 0.5 to 5 parts by weight, The slidability such as friction characteristics and wear characteristics is further improved.

Since a polyamide resin having a relative viscosity of 1.0 to 4.5 is used in a range of 95 to 70 parts by weight, a resin composition having excellent mechanical properties can be obtained. Therefore, a molded article made of the above resin composition can be suitably used as a sliding member excellent in both mechanical properties and slidability, such as a door check lever of an automobile.

[Brief description of the drawings]

FIG. 1 is a perspective view of a conventional door check lever of a general automobile.

[Explanation of symbols]

 Reference Signs List 1 lever for door check 2 polyamide resin composition 3 metal

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // C08J 5/00 CFG C08J 5/00 CFG (C08L 77/00 23:02)

Claims (4)

[Claims] 1. A polyamide resin having a relative viscosity of 1.0 to 4.5, 95 to 70 parts by weight, and an ultrahigh molecular weight polyolefin 5 to 3
A polyamide resin composition comprising 0 parts by weight. 2. The polyamide resin composition 1 according to claim 1.
A polyamide resin composition characterized in that at least one additive selected from talc or phosphate powder or lubricating oil is further blended in an amount of 5 parts by weight or less with respect to 00 parts by weight. . 3. A molded article using the polyamide resin composition according to claim 1. 4. The molded product according to claim 3, wherein the molded product is a door check lever.