JP2016056324A - Polyamide resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyamide resin composition maintaining the excellent mechanical physical properties of a polyamide resin and having particularly excellent sliding properties without depending on the kinds of mating material and the size of loads, and a molded body thereof.SOLUTION: There is provided a resin composition comprising: (X) a polyamide resin; and (Y) a graft copolymer, regarding the graft copolymer, (A) the main chain is made of an ethylene-glycidyl methacrylate copolymer, and (B) the side chains are made of (b-1) styrene and (b-2) one or more kinds selected from glycidyl methacrylate and methacrylate 2-hydroxypropyl.SELECTED DRAWING: None

Description

  The present invention relates to a polyamide composition having particularly excellent sliding properties while maintaining the excellent mechanical properties of polyamide, and is used in a wide range of fields such as electrical and electronic machine parts, precision equipment parts, and automobile parts. It can be done.

  Polyamide resins are widely used for sliding members such as bearings and gears because they are excellent in mechanical properties, heat resistance, chemical resistance and sliding properties. However, the required characteristics in these fields are becoming increasingly sophisticated, and further improvement in sliding characteristics is particularly desired. As such sliding characteristics, a friction coefficient, a wear amount, a sliding noise (squeak noise) and the like are taken up as important characteristics.

  As a method for improving the sliding characteristics of polyamide resin, in JP-A-4-20550 and Japanese Patent No. 3099396, a graft copolymer of polyethylene and acrylonitrile-styrene copolymer or methyl methacrylate is added, and sliding characteristics are added. The resin composition which improved is disclosed.

Japanese Patent Laid-Open No. 4-20550 JP-A-5-93129

However, these additives have a high coefficient of dynamic friction but a sufficient slidability cannot be obtained in a sliding test using a metal as a counterpart material although the amount of wear is reduced.

  In view of the above problems, an object of the present invention is to maintain a polyamide resin having excellent mechanical properties, and a polyamide resin composition having particularly excellent sliding characteristics regardless of the type of the counterpart material and the load and its The object is to provide a molded body.

  In order to achieve the above object, as a result of intensive studies by the present inventors, by blending a graft copolymer consisting of a specific main chain and side chain with a polyamide resin, the type of the counterpart material and the magnitude of the load can be reduced. It has been found that it has particularly excellent sliding properties, and has excellent mechanical properties, heat resistance, and dispersibility in polyamide resin.

That is, the present invention is a resin composition comprising (X) a polyamide resin and (Y) a graft copolymer,
The graft copolymer is (A) the main chain is an ethylene-glycidyl methacrylate copolymer, (B) the side chain is (b-1) styrene, (b-2) glycidyl methacrylate and methacrylic acid 2 A graft copolymer comprising at least one selected from hydroxypropyl.

According to the polyamide resin composition of the present invention, there are provided a polyamide resin composition and a molded product thereof that maintain the mechanical properties of polyamide and have particularly excellent sliding characteristics regardless of the type of the counterpart material and the load. can do.

  Embodiments of the present invention will be described below. The polyamide resin composition of the present invention contains the following (X) component and (Y) component. Hereinafter, each component will be described.

[(X) component]
The component (X) in the present invention is a polyamide resin and is not particularly limited as long as it is a polymer having an amide bond (—NHCO—) in the main chain. For example, polycaprolactam (nylon 6), polytetramethylene adipa Amide (nylon 46), polyhexamethylene adipamide (nylon 66), polyhexamethylene sebamide (nylon 610), polyhexamethylene dodecamide (nylon 612), polyundecamethylene adipamide (nylon 116), Polyundecalactam (Nylon 11), Polydodecalactam (Nylon 12), Polytrimethylhexamethylene terephthalamide (Nylon TMHT), Polyhexamethylene isophthalamide (Nylon 6I), Polynonamethylene terephthalamide (9T), Polyhexamethylene Terephthal Amide (6T), polybis (4-aminocyclohexyl) methane dodecamide (nylon PACM12), polybis (3-methyl-aminocyclohexyl) methane dodecamide (nylon dimethyl PACM12), polymetaxylylene adipamide (nylon MXD6), poly Undecamethylene hexahydroterephthalamide (nylon 11T (H)), polyamide copolymers containing at least two different polyamide-forming components, and mixtures thereof.

[(Y) component]
The component (Y) in the present invention is a graft copolymer, (A) the main chain is an ethylene-glycidyl methacrylate copolymer, (B) the side chain is (b-1) styrene, and (b -2) A graft copolymer comprising at least one selected from glycidyl methacrylate and 2-hydroxypropyl methacrylate.

The graft copolymer is a graft copolymer composed of 50 parts by weight or more and 90 parts by weight or less (A) main chain and 10 parts by weight or more and 50 parts by weight or less (B) side chain.

In the graft copolymer, if the proportion of the main chain (A) is less than 50 parts by weight, the slidability of the resin composition decreases, and if the proportion of the main chain exceeds 90 parts by weight, The dispersibility of coalescence is lowered, and the mechanical properties are lowered. On the other hand, the resin composition containing the graft copolymer in which the ratio of (A) main chain and (B) side chain is in the above range shall have high slidability and high mechanical properties. Is possible.

Said (B) side chain consists of (b-1) and (b-2), It is preferable that the ratio of (b-1) is 50 to 99 weight part. Moreover, (b-2) consists of 1 or more types chosen from glycidyl methacrylate and 2-hydroxypropyl methacrylate, and these can be used together in arbitrary ratios.

The ratio of (b-1) and (b-2) in the side chain (B) of the graft copolymer affects the slidability and mechanical properties of the resin composition. The resin composition containing the graft copolymer in which the ratio of (b-1) and (b-2) is in the above range can have high slidability and high mechanical properties.

    In the polyamide resin composition of the present invention, the (Y) graft copolymer is preferably 3 to 30 parts by mass and more preferably 5 to 20 parts by mass with respect to 100 parts by mass of the (X) polyamide resin. preferable. When the blending amount is less than 3 parts by mass, sufficient slidability cannot be obtained, and when it exceeds 30 parts by mass, the appearance of the resin composition tends to deteriorate.

  In the present invention, a lubricant such as mineral oil, hydrocarbon, fatty acid, alcohol, fatty acid ester, fatty acid amide, metal soap, natural wax, silicone, magnesium hydroxide, aluminum hydroxide, etc., without departing from the scope of the present invention. Inorganic flame retardants, organic flame retardants such as halogen and phosphorus, organic or inorganic fillers such as metal powder, talc, glass fiber, carbon fiber, wood powder, antioxidants, UV inhibitors, lubricants, dispersants Additives such as coupling agents, foaming agents, cross-linking agents, and colorants, and other polyolefin resins, polyester, polycarbonate, ABS resin, polyphenylene ether, polyphenylene sulfide, and other engineering plastics may be added.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.

(Evaluation of slidability 1)
Thrust-type friction and wear tester: Friction and wear tester EFM-III-F manufactured by Orientec Co., Ltd.
Evaluation material: Cylindrical material with an inner diameter of 20 mm and an outer diameter of 25.6 mm Evaluation material material: Partner material made of the composition of the present invention shown in Table 2: Cylindrical material with an inner diameter of 20 mm and an outer diameter of 25.6 mm: (1) Carbon steel (S45C), (2) Evaluation material and same material test conditions When the counterpart material is (1) carbon steel (S45C): load 50N, linear velocity 50cm / sec
When the counterpart material is (2) an evaluation material: load 20N, linear velocity 50 cm / sec

(Slidability evaluation 2)
Reciprocating sliding test machine: Rubbing tester 1566-A manufactured by Imoto Seisakusho Co., Ltd.
Evaluation material: flat plate having a length of 80 mm, a width of 10 mm, and a height of 4 mm. (Made by company)
Test conditions: load 3 kgf, linear speed 100 mm / sec, 5000 reciprocations

Further, the tensile strength and the flexural modulus measured in the examples and comparative examples were measured according to JIS shown below.
(Tensile strength)
JIS K-7113, test speed 50mm / min
(Flexural modulus)
JIS K-7203, test speed 2mm / min

(Production Example 1-1)
In a stainless steel autoclave with an internal volume of 5 L, 2500 g of pure water was added, and 2.5 g of polyvinyl alcohol was dissolved as a suspending agent. 700 g of ethylene-glycidyl methacrylate copolymer (trade name “Bond First E”, manufactured by Sumitomo Chemical Co., Ltd., GMA content 12%, MFR = 3 g / 10 min) (hereinafter abbreviated as EGMA), Stir to disperse. Separately, 1.5 g of benzoyl peroxide (trade name “Nyper BW”, manufactured by NOF Corporation) as a radical polymerization initiator, and t-butylperoxymethacryloyloxyethyl carbonate (hereinafter referred to as “radical (co) polymerizable organic peroxide”). 6 g of MEC) and 0.6 g of n-dodecyl mercaptan as a molecular weight regulator were dissolved in 210 g of styrene (hereinafter abbreviated as St) as a vinyl monomer and 90 g of glycidyl methacrylate (hereinafter abbreviated as GMA). The solution was put into the autoclave and stirred. Next, the autoclave was heated to 60 to 65 ° C. and stirred for 2 hours, whereby a vinyl monomer containing a radical polymerization initiator and a radical (co) polymerizable organic peroxide was converted into an ethylene-glycidyl methacrylate copolymer. Impregnated inside. Subsequently, the autoclave was heated to 80 to 85 ° C., maintained at that temperature for 7 hours for polymerization, washed with water and dried to obtain a poly (St / GMA / MEC) copolymer in EGMA pellets. This poly (St / GMA / MEC) copolymer was extracted from the pellet with ethyl acetate, and the weight average molecular weight was measured by GPC. As a result, it was 340,000. Next, this grafted precursor was extruded at 200 ° C. with a Laboplast mill single screw extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd.) and grafted to obtain white pellets.
When this graft copolymer was observed with a scanning electron microscope (“JEOL JSM T300”, manufactured by JEOL Ltd.), a true spherical resin having a particle size of 0.1 to 0.2 μm was uniformly dispersed.

With the compositions described in Table 1, graft copolymers according to Production Examples 1-2 to 1-8 and Comparative Production Examples 1-1 to 1-4 were produced. In addition, the abbreviation in Table 1 shows the following.
EGMA: ethylene-glycidyl methacrylate copolymer LDPE: low density polyethylene (“SUMICA GEN G401” manufactured by Sumitomo Chemical Co., Ltd., density = 0.926 g / cm 3)
St: Styrene GMA: Glycidyl methacrylate HPMA: 2-hydroxypropyl methacrylate AN: Acrylonitrile MMA: Methyl methacrylate

(Examples 1-1 to 1-10, Comparative Examples 1-1 to 1-4)
A predetermined amount of the graft copolymer obtained in Table 1 was dry blended with polyamide (trade name “Leona 1300S”, manufactured by Asahi Kasei Chemicals Corporation) at a blending ratio shown in Table 2, and set to 260 ° C. The mixture was melt kneaded with a twin screw extruder to obtain pellets.

The pellets according to each Example and each Comparative Example in Table 2 were molded by an injection molding machine to prepare an evaluation material. The injection molding conditions are barrel temperature: 265 ° C. and mold temperature: 90 ° C. Using the obtained evaluation material, tensile strength, flexural modulus, wear amount, and dynamic friction coefficient were measured. The results are shown in Table 2. In addition, the abbreviation in Table 2 shows the following.
PA: Polyamide resin

  From the evaluation results of the above Examples and Comparative Examples, the polyamide resin composition of the present invention uses a graft copolymer composed of a specific main chain and side chain, thereby maintaining slidability while maintaining mechanical properties. It turns out that it is greatly improved.

Claims (1)

(X) Polyamide resin containing 3 to 30 parts by weight of (Y) graft copolymer with respect to 100 parts by weight of polyamide resin, wherein (Y) graft copolymer is
(A) The main chain is an ethylene-glycidyl methacrylate copolymer,
(B) The side chain is
(B-1) styrene,
(B-2) a graft copolymer comprising at least one selected from glycidyl methacrylate and 2-hydroxypropyl methacrylate,
A polyamide resin composition characterized by the above.