JP6435851B2 - Polyamide resin composition and resin molded product - Google Patents

Description

  The present invention relates to a polyamide resin composition that can be used as a sliding member, and a resin molded product.

  Polyamide resins are excellent in mechanical properties, heat resistance, chemical resistance, and sliding properties. For this reason, polyamide resins are widely used for sliding members such as bearings and gears. However, in recent years, the sliding characteristics required for such sliding members have been advanced. Examples of the sliding characteristics required for the sliding member include a friction coefficient, a wear amount, a sliding sound (squeak noise), and the like.

  Techniques for improving the sliding characteristics of polyamide resin are disclosed in Patent Documents 1 and 2. In the techniques described in Patent Documents 1 and 2, the sliding properties of the polyamide resin are improved by adding a graft copolymer of polyethylene and acrylonitrile-styrene copolymer or methyl methacrylate as an additive. .

Japanese Patent Laid-Open No. 4-20550 Japanese Patent No. 3099396

  However, in the polyamide resin to which the additive according to Patent Documents 1 and 2 is added, although a good result is obtained in a sliding test using a metal as a counterpart material, the counterpart material is the same material, that is, between the polyamide resins. In the sliding test, sufficient results cannot be obtained.

  In view of the circumstances as described above, an object of the present invention is to provide a polyamide resin composition and a resin molded product that can obtain excellent sliding characteristics regardless of the counterpart material.

In order to achieve the above object, a polyamide resin composition according to one embodiment of the present invention contains 100 parts by weight of (A) a polyamide resin and 0.5 to 20 parts by weight of (B) a graft copolymer. To do.
The (B) graft copolymer is composed of 40 to 60% by weight of polyethylene and 40 to 60% by weight of acrylonitrile-styrene copolymer, the main chain is the polyethylene, and the side chain is the acrylonitrile. -Styrene copolymer.
The acrylonitrile-styrene copolymer is composed of 10 to 50% by weight of acrylonitrile component and 50 to 90% by weight of styrene component.
With the polyamide resin composition having this configuration, excellent sliding properties can be obtained regardless of the counterpart material while maintaining the excellent mechanical properties of the (A) polyamide resin.

  The resin molded product according to one embodiment of the present invention is obtained by molding the polyamide resin composition.

  It is possible to provide a polyamide resin composition and a resin molded product capable of obtaining excellent sliding characteristics regardless of the counterpart material.

  Hereinafter, an embodiment of the present invention will be described.

[Polyamide resin composition]
The polyamide (PA) resin composition according to this embodiment contains (A) a polyamide resin (PA) and (B) a graft copolymer. In this polyamide resin composition, by adding (A) polyamide resin to (B) graft copolymer, (A) high sliding characteristics are obtained without impairing the excellent mechanical properties and molded appearance of polyamide resin. can get. In particular, in this polyamide resin composition, good results can be obtained not only in a sliding test using another material such as a metal as a counterpart, but also in a sliding test between the polyamide resin compositions.

  In the polyamide resin composition according to this embodiment, the amount of (B) graft copolymer added to 100 parts by weight of (A) polyamide resin is 0.5 to 20 parts by weight, and 3 to 15 parts by weight. It is preferable. In this polyamide resin composition, high sliding characteristics can be obtained by setting the addition amount of (B) graft copolymer to 0.5 parts by weight or more, and even higher sliding characteristics can be obtained by setting it to 3 parts by weight or more. can get. In addition, in this polyamide resin composition, a good molding appearance can be obtained by setting the amount of (B) graft copolymer to 20 parts by weight or less, and a more favorable molding appearance by setting it to 15 parts by weight or less. can get.

  (A) The polyamide resin is a polymer having an amide bond (—NHCO—) in the main chain. (A) The polyamide resin is not limited to a specific type. For example, polycaprolactam (nylon 6), polytetramethylene adipamide (nylon 46), polyhexamethylene adipamide (nylon 66), polyhexamethylene Sebacamide (nylon 610), polyhexamethylene dodecamide (nylon 612), polyundecamethylene adipamide (nylon 116), polyundecalactam (nylon 11), polydodecalactam (nylon 12), polytrimethylhexa Methylene terephthalamide (nylon TMHT), polyhexamethylene isophthalamide (nylon 6I), polynonane methylene terephthalamide (9T), polyhexamethylene terephthalamide (6T), polybis (4-aminocyclohexyl) methane dodeca (Nylon PACM12), polybis (3-methyl-aminocyclohexyl) methane dodecamide (nylon dimethyl PACM12), polymetaxylylene adipamide (nylon MXD6), polyundecamethylene hexahydroterephthalamide (nylon 11T (H)) Etc. (A) The polyamide resin may be composed of a single type or may include a plurality of types.

  (B) The graft copolymer has polyethylene as the main chain and acrylonitrile-styrene copolymer as the side chain. (B) In the graft copolymer, when the total content of polyethylene and acrylonitrile-styrene copolymer is 100% by weight, the polyethylene content is 40-60% by weight, and the acrylonitrile-styrene copolymer The content is 40 to 60% by weight. Further, in the acrylonitrile-styrene copolymer, when the total content of the acrylonitrile component and the styrene component is 100% by weight, the content of the acrylonitrile component is 10 to 50% by weight, and the content of the styrene component is 50 to 50%. 90% by weight. By adding the (B) graft copolymer having such a configuration to the (A) polyamide resin, the excellent mechanical properties and molded appearance of the (A) polyamide resin are not impaired, and the material is excellent regardless of the counterpart material. A polyamide resin composition having excellent sliding properties is obtained.

  The polyamide resin composition may further contain subcomponents other than (A) the polyamide resin and (B) the graft copolymer, if necessary. Such subcomponents include, for example, (1) lubricants, (2) inorganic flame retardants, (3) organic flame retardants, (4) organic or inorganic fillers, (5) various additives, (6) Examples include engineering plastics.

More specifically, examples of (1) the lubricant include mineral oil, hydrocarbon, fatty acid, alcohol, fatty acid ester, fatty acid amide, metal soap, natural wax, and silicone.
(2) Examples of the inorganic flame retardant include magnesium hydroxide and aluminum hydroxide.
(3) Examples of organic flame retardants include halogen-based and phosphorus-based flame retardants.
(4) Examples of the organic or inorganic filler include metal powder, talc, glass fiber, carbon fiber, and wood powder.
(5) Examples of the various additives include antioxidants, ultraviolet inhibitors, lubricants, dispersants, coupling agents, foaming agents, crosslinking agents, and coloring agents.
(6) Examples of the engineering plastic include other polyolefin resins, polyester, polycarbonate, ABS resin, polyphenylene ether, polyphenylene sulfide, and the like.

[Resin molded product]
Since the polyamide resin composition according to this embodiment is a thermoplastic resin, it can be easily molded into various shapes by injection molding, extrusion molding, or the like. Since the resin molded product obtained by molding the polyamide resin composition according to the present embodiment is excellent in molding appearance, mechanical properties, and sliding properties, various types such as automobiles, OA electronic devices, electrical devices, electronic devices, etc. Widely applicable in the field.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto.

[Preparation of test piece]
(Test piece preparation method)
About Examples 1-10 and Comparative Examples 1-10, the kind and quantity of (A) polyamide resin and (B) graft copolymer were changed, and the test piece was produced. Specifically, (A) polyamide resin and (B) graft copolymer are melt-kneaded (extrusion temperature: 250 to 270 ° C.) with a twin-screw extruder (PCM-30: manufactured by Ikegai) to form a pellet. A polyamide resin composition was obtained. Subsequently, this pellet was injection-molded (barrel temperature: 260 to 270 ° C., mold temperature: 80 ° C.) to obtain a test piece which is a resin molded product.

Example 1
(A) Polyamide 66 (manufactured by Ube Industries, trade name: ube nylon 2020B, standard grade) was used as the polyamide resin. (B) As the graft copolymer, a graft copolymer having a main chain of polyethylene (PE) and a side chain of acrylonitrile (AN) -styrene (St) copolymer was used. The amount of (B) graft copolymer added to 100 parts by weight of (A) polyamide resin was 5 parts by weight.

  (B) As for content of each component of the graft copolymer, polyethylene (PE) is 50% by weight, acrylonitrile (AN) is 15% by weight, and styrene (St) is 35% by weight. Hereinafter, the content of each component of the (B) graft copolymer is abbreviated as “PE / AN / St = 50 wt% / 15 wt% / 35 wt%”.

(Example 2)
In Example 2, the types of (A) polyamide resin and (B) graft copolymer were the same as in Example 1, and the amount of (B) graft copolymer added to 100 parts by weight of (A) polyamide resin was 1 Part by weight.

Example 3
In Example 3, the types of (A) polyamide resin and (B) graft copolymer were the same as in Example 1, and the amount of (B) graft copolymer added to 100 parts by weight of (A) polyamide resin was 20 parts. Part by weight.

(Example 4)
In Example 4, (A) Polyamide 6 (manufactured by Ube Industries, Ltd., trade name: ube nylon 1013B, standard grade) was used as the polyamide resin, and the type and amount of (B) graft copolymer were set in Example 1. And the same.

(Example 5)
In Example 5, (A) Polyamide 612 (manufactured by DuPont Co., Ltd., trade name: Zytel 151L, standard grade) was used as the polyamide resin, and (B) the type and amount of graft copolymer were the same as in Example 1. It was.

(Example 6)
In Example 6, (A) polyamide 66 (made by DuPont Co., Ltd., trade name: Zytel 70G33L, reinforced grade), which is a reinforced grade added with 33% by weight of glass fiber as a polyamide resin, was used. The type and amount of coalescence were the same as in Example 1.

(Example 7)
In Example 7, as the graft copolymer (B), a graft copolymer having a main chain of polyethylene and a side chain of acrylonitrile-styrene copolymer (PE / AN / St = 60% by weight / 12% by weight) / 28 wt%), and the amount of (A) the type of polyamide resin and the amount of (B) graft copolymer added were the same as in Example 1.

(Example 8)
In Example 8, as the graft copolymer (B), a graft copolymer having a main chain of polyethylene and a side chain of acrylonitrile-styrene copolymer (PE / AN / St = 40% by weight / 18% by weight) / 42 wt%), and the amount of (A) the type of polyamide resin and the amount of (B) graft copolymer added were the same as in Example 1.

Example 9
In Example 9, as the graft copolymer (B), a graft copolymer (PE / AN / St = 50 wt% / 25 wt%) in which the main chain is polyethylene and the side chain is an acrylonitrile-styrene copolymer / 25 wt%), and the amount of (A) the type of polyamide resin and the amount of (B) graft copolymer added were the same as in Example 1.

(Example 10)
In Example 10, as the graft copolymer (B), a graft copolymer in which the main chain is polyethylene and the side chain is an acrylonitrile-styrene copolymer (PE / AN / St = 50% by weight / 7.5) Weight% / 42.5 weight%), and the amount of (A) the type of polyamide resin and the amount of (B) graft copolymer added were the same as in Example 1.

(Comparative Example 1)
In Comparative Example 1, the type of (A) polyamide resin was the same as in Example 1, and (B) the graft copolymer was not used. That is, Comparative Example 1 is different from Example 1 in that it does not contain (B) a graft copolymer.

(Comparative Example 2)
In Comparative Example 2, the types of (A) polyamide resin and (B) graft copolymer were the same as in Example 1, and the amount of (B) graft copolymer added to 100 parts by weight of (A) polyamide resin was 30. Part by weight. That is, in the polyamide resin composition according to Comparative Example 2, the amount of (B) graft copolymer added is larger than 20 parts by weight which is the upper limit of the polyamide resin composition according to the above embodiment.

(Comparative Example 3)
In Comparative Example 3, the types of (A) polyamide resin and (B) graft copolymer were the same as in Example 1, and the amount of (B) graft copolymer added to 100 parts by weight of (A) polyamide resin was 0. .1 part by weight. That is, in the polyamide resin composition according to Comparative Example 3, the amount of (B) graft copolymer added is less than 0.5 parts by weight which is the lower limit of the polyamide resin composition according to the above embodiment.

(Comparative Example 4)
In Comparative Example 4, instead of (B) the graft copolymer, a blend of polyethylene and acrylonitrile-styrene copolymer (PE / P (AN / St)) that is not graft copolymerized is used, and (A) The type of polyamide resin was the same as in Example 1, and the amount of blend (PE / P (AN / St)) added was the same as the amount of (B) graft copolymer added in Example 1.

(Comparative Example 5)
In Comparative Example 5, as the graft copolymer (B), a graft copolymer having a main chain of polyethylene and a side chain of acrylonitrile-styrene copolymer (PE / AN / St = 70% by weight / 9% by weight) / 21 wt%), and the amount of (A) the type of polyamide resin and the amount of (B) graft copolymer added were the same as in Example 1. That is, in the polyamide resin composition according to Comparative Example 5, the amount of polyethylene in (B) the graft copolymer is larger than 60% by weight which is the upper limit of the polyamide resin composition according to the above embodiment.

(Comparative Example 6)
In Comparative Example 6, as the graft copolymer (B), a graft copolymer having a main chain of polyethylene and a side chain of acrylonitrile-styrene copolymer (PE / AN / St = 30% by weight / 21% by weight) / 49 wt%), and (A) the type of polyamide resin and (B) the addition amount of the graft copolymer were the same as in Example 1. That is, in the polyamide resin composition according to Comparative Example 6, the amount of polyethylene in (B) the graft copolymer is less than 40% by weight which is the lower limit of the polyamide resin composition according to the above embodiment.

(Comparative Example 7)
In Comparative Example 7, polyethylene was used instead of (B) the graft copolymer, (A) the type of polyamide resin was the same as in Example 1, and the amount of polyethylene added was (B) the graft copolymer of Example 1. The amount of addition was the same.

(Comparative Example 8)
In Comparative Example 8, (A) the type of polyamide resin was the same as in Example 4, and (B) the graft copolymer was not used. That is, Comparative Example 8 differs from Example 4 in that it does not contain (B) a graft copolymer.

(Comparative Example 9)
In Comparative Example 9, the type of (A) polyamide resin was the same as in Example 5, and (B) the graft copolymer was not used. That is, Comparative Example 9 is different from Example 5 in that (B) the graft copolymer is not included.

(Comparative Example 10)
In Comparative Example 10, the type of (A) polyamide resin was the same as in Example 6, and (B) the graft copolymer was not used. That is, Comparative Example 10 differs from Example 6 in that it does not contain (B) a graft copolymer.

[Evaluation method]
(Evaluation of molding appearance)
The appearance of each test piece was visually evaluated. The evaluation criteria are as follows.
○: Good (no flow mark, jetting, peeling, etc.)
X: Defect (There are flow marks, jetting, peeling, etc.)

(Evaluation of impact resistance)
As mechanical properties of each test piece, impact resistance was evaluated by measuring impact strength. The impact strength measurement was performed at a test speed of 50 mm / min according to JIS K-7113.

(Evaluation of sliding characteristics)
As an evaluation of the sliding characteristics of each test piece, a thrust type frictional wear test having the following contents was performed.
・ Testing machine: Friction and wear testing machine EFM-III-F manufactured by Orientec Co., Ltd.
-Test piece shape: cylinder with an inner diameter of 20 mm and an outer diameter of 25.6 mm-Composition of the test piece: see above and Figs. 1 and 2-Shape of mating material: cylinder with an inner diameter of 20 mm, outer diameter of 25.6 mm : Resin (PA66, PBT, POM), same material (same as each test piece), carbon steel (S45C)
Test conditions: Load 20N, linear velocity 50CM / SEC (resin and the same material), load 50N, linear velocity 50CM / SEC (carbon steel)

[Evaluation results (Examples 1 to 10)]
Table 1 shows the evaluation results of Examples 1-10.

(Examples 1 to 10)
As shown in Table 1, a good molded appearance was obtained in any of the test pieces of Examples 1 to 10. Moreover, the high impact strength of 4.5 (kJ / m < ² >) or more was obtained also in any test piece of Examples 1-10.

  Furthermore, in any of the test pieces of Examples 1 to 10, good sliding characteristics were obtained regardless of the counterpart material. Specifically, in a frictional wear test in which the counterpart material is resin (PA66), the coefficient of dynamic friction was a low value of 0.25 or less, and a small amount of wear was 3.2 mg or less. In the friction wear test in which the counterpart material is resin (PBT), the coefficient of dynamic friction was as low as 0.22 or less, and the wear amount was as small as 2.3 mg or less. In the frictional wear test in which the counterpart material is resin (POM), the coefficient of dynamic friction was as low as 0.25 or less and the wear amount was as small as 2.1 mg or less. In the friction wear test between the test pieces using the same material as the counterpart material, that is, a low dynamic friction coefficient of 0.21 or less and a small wear amount of 2.6 mg or less. In the friction wear test in which the counterpart material is carbon steel (S45C), the coefficient of dynamic friction was as low as 0.23 or less, and the wear amount was as small as 1.9 mg or less.

[Evaluation results (Comparative Examples 1 to 10)]
Table 2 shows the evaluation results of Comparative Examples 1-10.

(Comparative Examples 1, 8, 9, 10)
Comparative Examples 1, 8, 9, and 10 differ from Examples 1, 4, 5, and 6, respectively, in that they do not contain (B) a graft copolymer. That is, the evaluation results of Comparative Examples 1, 8, 9, and 10 are based only on various (A) polyamide resins. For this reason, in the polyamide resin composition according to Comparative Examples 1, 8, 9, and 10, good molding appearance and impact resistance are obtained due to the properties of (A) the polyamide resin itself.

  On the other hand, in the frictional wear test in Comparative Examples 1, 8, and 9, both the dynamic friction coefficient and the wear amount were inferior to those of Examples 1, 4, and 5 in any of the counterpart materials. Moreover, in the frictional wear test in Comparative Example 10, when the counterpart material is carbon steel, the dynamic friction coefficient and the wear amount equivalent to those in Example 6 are obtained, but the counterpart material is a resin or the same material. Both the dynamic friction coefficient and the wear amount were inferior to those of Example 6.

  By comparing Examples 1, 4, 5, 6 and Comparative Examples 1, 8, 9, 10 with the addition of the (B) graft copolymer, the sliding properties of the polyamide resin composition are greatly improved. I understand that.

(Comparative Example 2)
In the polyamide resin composition according to Comparative Example 2, the amount of (B) graft copolymer added is greater than 20 parts by weight which is the upper limit of the polyamide resin composition according to the above embodiment. With this polyamide resin composition, a good molded appearance was not obtained, and the impact resistance was also inferior to that of Example 1. Further, in this polyamide resin composition, the dynamic friction coefficient equivalent to that of Example 1 is obtained for any counterpart material, but when the counterpart material is a resin or the same material, the wear amount is high. It was significantly inferior to Example 1.

  By comparing the amount of the (B) graft copolymer to 20 parts by weight or less by comparing Example 1 with Comparative Example 2, the molding appearance and impact resistance are improved, and the sliding of the polyamide resin composition is improved. It can be seen that the characteristics are greatly improved.

(Comparative Example 3)
In the polyamide resin composition according to Comparative Example 3, the amount of (B) graft copolymer added is less than 0.5 parts by weight which is the lower limit of the polyamide resin composition according to the above embodiment. In this polyamide resin composition, although a good molded appearance was obtained, the impact resistance was inferior to that of Example 1. Further, in this polyamide resin composition, when the counterpart material is a resin, the same dynamic friction coefficient and wear amount as in Example 1 are obtained, but when the counterpart material is the same material or carbon steel. Both the dynamic friction coefficient and the wear amount were inferior to those of Example 1.

  By comparing Example 1 and Comparative Example 3 with the addition amount of the (B) graft copolymer being 0.5 parts by weight or more, impact resistance is improved and sliding properties of the polyamide resin composition are improved. It can be seen that the amount of wear is greatly reduced especially when the counterpart material is the same material or carbon steel.

(Comparative Example 4)
In the polyamide resin composition according to Comparative Example 4, (A) a polyamide resin, instead of (B) a graft copolymer, a blend of a non-grafted polyethylene and an acrylonitrile-styrene copolymer ( PE / P (AN / St)) was added. With this polyamide resin composition, a good molded appearance was not obtained, and the impact resistance was also inferior to that of Example 1. Moreover, in this polyamide resin composition, in any case of any counterpart material, both the dynamic friction coefficient and the wear amount were significantly inferior to those of Example 1.

  Comparison between Example 1 and Comparative Example 4 shows that the addition of (B) graft copolymer improves the molding appearance and impact resistance and greatly improves the sliding properties of the polyamide resin composition. I understand.

(Comparative Example 5)
In the polyamide resin composition according to Comparative Example 5, the amount of polyethylene in (B) the graft copolymer is more than 60% by weight, which is the upper limit of the polyamide resin composition according to the above embodiment. With this polyamide resin composition, a good molded appearance was not obtained, and the impact resistance was also inferior to that of Example 1. Further, in this polyamide resin composition, when the counterpart material is carbon steel, the dynamic friction coefficient and the wear amount equivalent to those of Example 1 are obtained, but when the counterpart material is resin or the same material. Both the dynamic friction coefficient and the wear amount were inferior to those of Example 1.

  By comparing Example 1 and Comparative Example 5 with the amount of polyethylene in (B) the graft copolymer being 60% by weight or less, the molding appearance and impact resistance are improved and the polyamide resin composition is slid. It can be seen that the dynamic characteristics are improved, and the amount of wear is particularly reduced when the counterpart material is a resin.

(Comparative Example 6)
In the polyamide resin composition according to Comparative Example 6, the amount of polyethylene in (B) the graft copolymer is less than 40% by weight which is the lower limit of the polyamide resin composition according to the above embodiment. With this polyamide resin composition, a good molded appearance was not obtained, and the impact resistance was also inferior to that of Example 1. Moreover, in this polyamide resin composition, in any case of any counterpart material, both the dynamic friction coefficient and the wear amount were significantly inferior to those of Example 1.

  By comparing Example 1 and Comparative Example 6 with the amount of polyethylene in the (B) graft copolymer being 40% by weight or more, the molding appearance and impact resistance are improved, and the sliding of the polyamide resin composition is improved. It can be seen that the dynamic characteristics are greatly improved.

(Comparative Example 7)
In the polyamide resin composition according to Comparative Example 7, polyethylene was added instead of (B) the graft copolymer to (A) the polyamide resin. With this polyamide resin composition, a good molded appearance was not obtained, and the impact resistance was also inferior to that of Example 1. Moreover, in this polyamide resin composition, in any case of any counterpart material, both the dynamic friction coefficient and the wear amount were significantly inferior to those of Example 1.

  According to a comparison between Example 1 and Comparative Example 7, the appearance of molding was not obtained by adding (B) a graft copolymer in which the main chain is polyethylene and the side chain is acrylonitrile-styrene copolymer, not polyethylene alone. In addition, the impact resistance is improved, the sliding characteristics of the polyamide resin composition are improved, and the wear amount is significantly reduced.

  The embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the present invention.

Claims (2)

100 parts by weight of (A) polyamide resin and 0.5 to 20 parts by weight of (B) graft copolymer,
(B) the graft copolymer, when the total weight of the graft copolymer is 100 wt%, and polyethylene main chain, which accounts for 40 to 60 wt%, acrylonitrile accounts for 40 to 60% by weight - styrene copolymer a polymer side chain moiety is constituted by,
The acrylonitrile - styrene copolymer side chain moieties, the acrylonitrile - when the total weight of the styrene copolymer side chain moieties to 100 wt%, and unit 10 to 50% by weight derived from acrylonitrile, unit 50 derived from styrene ~ 90 % by weight polyamide resin composition A resin molded product obtained by molding the polyamide resin composition according to claim 1 .