JPS646667B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polyamide resin composition well known as nylon-6 resin or nylon-66 resin, and more specifically to a polyamide resin reinforced with a reinforcing filler and improved in appearance, surface smoothness, and moldability of a molded product. This invention relates to a resin composition. Adding reinforcing fillers to polyamide resins improves heat resistance, rigidity, dimensional stability, etc., and has become widely used in recent years. Recently, it is expected to be used as an exterior material for automobiles, electrical appliances, etc. by taking advantage of its heat resistance and giving a metal-like appearance to the surface of molded products. However, molded products obtained from filler-added polyamide resins have poor surface appearance due to the filler, and especially when metal surface treatment such as plating or vapor deposition is applied, the appearance becomes noticeably uneven. Therefore, it is desired to further improve the moldability and the appearance surface smoothness of molded products for exterior materials subjected to metallization treatment. In particular, consideration is being given to converting conventional metal materials into resins for automotive applications, and materials with higher heat resistance and mechanical strength are required. The problem is that the reinforcing agent has a large reinforcing effect, but on the other hand, the appearance of the molded product deteriorates.Currently, a resin composition that satisfies the appearance, strength, and heat resistance has not been obtained. . In view of the current situation, the present inventors have conducted intensive studies to improve the appearance, surface smoothness, and moldability of polyamide resin by imparting high heat resistance and mechanical properties. By using a filler with a specific particle size and a particle size distribution, it is possible to significantly improve the appearance and surface smoothness of polyamide resin molded products, as well as provide excellent heat resistance and mechanical properties. They have discovered that something can be obtained, and have arrived at the present invention. That is, the present invention provides (1) polyamide resin (A) 95~
40% by weight, 1 to 40% by weight of fibrous filler (B) with a fiber length of more than 15μ and less than 300μ, average particle diameter _D50 of 2μ or more
3 to 58% by weight of inorganic filler (C) with a particle size of 10 μ or less, and 1 to 25% by weight of an inorganic filler (A) with an average particle size D ₅₀ of less than 2 μ
and polycaprolactone (E) per 100 parts by weight of the above resin composition.
The present invention relates to a polyamide resin composition containing 0.1 to 5 parts by weight of. The polyamide resin (A) used in the present invention includes nylon-6 resin obtained by ring-opening polymerization of ε-caprolactam, nylon-66 resin obtained by polymerizing hexamethylene diamine and adipic acid, and the like. A product obtained by copolymerizing a small amount of other copolymerizable monomers may also be used. The fibrous filler (B) with a fiber length of more than 15 μm and less than 300 μm includes glass fiber (commonly marketed as milled fiber, cut fiber, glass powder, etc.), asbestos acicular calcium metasilicate (wollastonite), fibers), gypsum whiskers, potassium titanate whiskers, metal fibers, processed mineral fibers, etc., and the fiber length is
It is more than 15μ and less than 300μ. As the fiber length becomes longer, the reinforcing effect becomes higher, but the appearance of the molded product deteriorates, which is not preferable. These fibers may be used alone or in combination, and fibers subjected to various surface treatments are also preferably used. Glass milled fibers and potassium titanate whiskers are particularly preferably used. The amount of the fibrous filler (B) added is 1 to 40% by weight of the resin composition. Addition amount is 1% by weight
If it is less than 40% by weight, the reinforcing effect will be small, and if it exceeds 40% by weight, moldability and appearance will deteriorate, which is not preferable. Especially 3
A range of ~30% by weight is preferred. Inorganic fillers (C) with an average particle diameter _D50 of 2μ or more and 10μ or less include amorphous glass powder, glass beads, glass flakes, talc, clay, kaolin, calcium metasilicate powder, dawsonite, and silica powder. , quartz powder, mica powder,
One or more types selected from metal powder, boron nitride powder, graphite, etc. The amount of the inorganic filler (C) added is 3 to 58% by weight. If it is less than 3% by weight, the reinforcing effect will not be sufficiently achieved, and if it exceeds 58% by weight, the appearance will deteriorate, which is not preferable. Furthermore, the inorganic filler (D) with an average particle diameter D ₅₀ of less than 2 μm includes glass powder, talc,
Various materials can be mentioned such as clay, kaolin, calcium carbonate, calcium metasilicate powder, silica powder, metal powder, titanium oxide, and carbon black.If the average particle size _D50 is less than 2μ, it can be used alone or in combination of two or more. It may also be the same component as the filler (C). Particularly preferred are particles with a particle size of 1 μm or less. The amount of filler (D) added is 1 to 25% by weight. If the amount is less than 1% by weight, the effect of improving appearance is insufficient, and if the amount added exceeds 25% by weight, the effect of improving appearance is small and the reinforcing effect is also reduced, which is not preferable. The amount of filler (D) added is particularly between 3% by weight and 20% by weight.
A weight percent range is preferred. As the fillers (C) and (D), fillers that have been subjected to various surface treatments are also preferably used. The polyamide resin (A) blended with the fillers (B), (C) and (D) exhibits high heat resistance and mechanical strength, and the fillers have a preferable particle size distribution.
The appearance and surface smoothness of the molded product are significantly improved.
Therefore, although conventional resins reinforced with fibrous fillers such as glass fiber reinforced polyamide resins have excellent mechanical and thermal properties, they have poor appearance, especially surface smoothness, and must be treated with plating or other treatments before use. However, with the resin composition of the present invention, plating,
It shows good appearance even after metallization treatment such as vapor deposition. A further object of the present invention is to improve the moldability of such polyamide resins. Polyamide resins reinforced with fillers have poor moldability, and there are many restrictions on molding conditions in order to obtain a particularly good appearance. The present inventors have found that the molded appearance of reinforced polyamide resin can be improved by blending the fillers (B), (C), and (D), but in addition, when the resin composition is It has been found that by blending 0.1 to 5 parts by weight of polycaprolactone (E) with respect to each part, moldability is further improved and a good appearance can be easily obtained. The polycaprolactone (E) added to the polyamide resin composition has the general formula or (In the formula, R represents an alkyl group) and has a molecular weight in the range of 1,000 to 100,000. When adding polycaprolactone (E),
The amount is preferably 0.1 parts by weight or more in order to fully exhibit the effect, and the amount is preferably 5 parts by weight or less since adding too much will lower the heat resistance. The resin composition of the present invention has excellent moldability, and the resulting molded products have excellent appearance, especially surface smoothness. It is suitable for exterior materials such as automobiles and electrical products that require high heat resistance and mechanical properties. Such resin compositions may contain stabilizers such as antioxidants, modifiers such as dyes and pigments, and epoxy resins, as necessary.
A mold release agent, a flame retardant, etc. can be added. To carry out the present invention, any method well known to those skilled in the art can be applied, such as pellets and/or powder of polyamide resin, fibrous filler with a fiber length of 300 μm or less, filler with a particle size of 2 μm or more and 10 μm or less. ,
It is obtained by weighing out a specified amount of filler with a particle size of less than 2 μm or polycaprolactone, mixing it in a V-type blender, mixer, etc., and feeding it into an extruder and heating and melt-mixing it. This will be explained in detail below using examples. Examples 1-3, Comparative Examples 1-3 Nylon-6 with a relative viscosity of 2.8 measured at 25°C in a 1% solution in 98% sulfuric acid, fibrous filler (B),
Inorganic fillers (C) and (D) and polycaprolactone (E) were weighed in the proportions shown in Table 1, mixed for 5 minutes in a V-type blender, and then melted at a cylinder temperature of 240°C using a 65φ single vent extruder. The resin composition of the present invention was obtained by extrusion and shaping into pellets. These were injection molded using a famous model SJ35B injection molding machine at a cylinder temperature of 280°C and a mold temperature of 120°C to obtain various molded products for evaluation. The compositions of the present invention had excellent moldability, especially those to which polycaprolactone was added had excellent fluidity, and the molded products obtained had good appearance and surface smoothness without sink marks or warpage. Table 1 shows the results of various evaluations performed using the obtained molded product.

【table】

[Table] The bending strength and elastic modulus in Table 1 are 127×12.7×
The heat distortion temperature was measured according to ASTM D790 using a 3.2 t specimen, and the heat distortion temperature was measured using ASTM D648 (load 18.6 Kg/cm ² ) using a 127 x 12.7 x 6.35 t specimen. The molded products were evaluated for their workability during injection molding using the following criteria. ◎: Good flowability and excellent formability 〇: Good formability △: Decreased formability ×: Poor formability The appearance after plating was determined using a 60 x 100 x 3t square plate, and after degreasing, tin chloride was used. - Using hydrochloric acid aqueous solution as an etching solution, catalyst-accelerator treatment was performed and chemical nickel was applied. Then about 20μ
Thick copper plating, approx. 1μ thick chrome plating,
The appearance of the dried plated product was visually evaluated. As is clear from Table 1, the composition of the present invention exhibits good moldability, and the plated molded products obtained have a good metal-like appearance, high smoothness, and heat resistance. It also has excellent strength and mechanical properties. On the other hand, Comparative Examples 1 to 3 were obtained and evaluated in exactly the same manner as in Example 1, except that the composition of the present invention and its constituent components were different. When glass fiber with a fiber length of 3 mm is used as in Comparative Example 1, although it has excellent mechanical and thermal properties, the appearance is poor even when used in combination with an inorganic filler, and the surface roughness after plating is significant, making it unsuitable for exterior applications. I can not use it. Furthermore, as in Comparative Examples 2 and 3, if the constituent components of the present invention are missing, a product with a satisfactory appearance cannot be obtained, and as in Comparative Example 3, heat resistance and moldability are lowered. By adjusting the fiber length and particle size distribution of the filler as in the composition of the present invention, a molded article with well-balanced moldability, appearance, strength, and heat resistance can be obtained. By adding it, the flow processability is improved, so molded products with good appearance can be easily obtained.

Claims (1)

[Claims] 1. Polyamide resin (A) 95-40% by weight, fiber length 15μ
1 to 40% by weight of fibrous filler (B) exceeding 300μ or less,
Inorganic filler (C) with an average particle diameter _D50 of 2μ or more and 10μ or less
An improved polyamide resin composition comprising 3 to 58% by weight of an inorganic filler (D) and 1 to 25% by weight of an inorganic filler (D) having an average particle size _D50 of less than 2μ. 2 Polyamide resin (A) 95-40% by weight, fiber length 15μ
1 to 40% by weight of fibrous filler (B) exceeding 300μ or less,
Inorganic filler (C) with an average particle diameter _D50 of 2μ or more and 10μ or less
Resin composition 100 consisting of 3 to 58% by weight and 1 to 25% by weight of an inorganic filler (D) with an average particle diameter _D50 of less than 2μ
0.1 to 5 parts by weight of polycaprolactone (E)
An improved polyamide resin composition comprising parts by weight.