JPH0260960A - Molding process - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for molding a molded article having a metallic appearance.

More specifically, the present invention relates to a method for molding a molded article that has excellent moldability and mechanical properties and has an excellent metallic appearance.

[Prior Art] Regardless of the type of substrate, such as metal, wood, stone, or plastics, in order to give these substrates a metallic appearance, it is common to apply a paint having a metallic appearance.

To give a plastic molded product a metallic look without painting it, for example, when using thermosetting resin, mix aluminum powder or mica powder with the resin such as transparent unsaturated polyester, which is the base material, and then cast it. There is a way to do it.

In addition, in order to obtain a metallic-like molded article from a thermoplastic resin composition, there are two methods: blending aluminum powder with a non-reinforced transparent resin that is not reinforced with glass fibers, such as acrylic resin, polycarbonate, polystyrene, etc., or using a slightly opaque resin. However, there is a method of adding aluminum powder to ABS resin to give it a metallic look.

However, these materials cannot be practically used in fields where strength, rigidity, heat resistance, etc. are required at the same time.

Generally, glass fibers and inorganic fillers are added to molding resins for the purpose of improving the strength, rigidity, and heat resistance of plastic molded products.

However, when pellets for molding are produced by further blending aluminum powder into the above-mentioned resin composition containing glass fibers and inorganic fillers, the surface of the aluminum powder is very soft, so processing steps such as an extruder are used to obtain the pellets. The surface of the aluminum is damaged by glass fibers and inorganic fillers, resulting in a significant decrease in gloss and resulting in products with low commercial value.

[Problems to be Solved by the Present Invention] An object of the present invention is to improve the problems of the prior art and to provide a method for molding a molded product having a metallic appearance and excellent strength, rigidity, and heat resistance. be.

[Means for Solving the Problems] As a result of intensive studies, the present inventors created pellets, which are molding materials, by separately melt-blending compositions consisting of polyamide resin, glass fiber, and polyamide resin and aluminum powder. The present invention has been completed based on the discovery that a molded article having a good metallic appearance can be obtained by mixing these pellets and injection molding the pellets.

That is, the present invention uses a molding material (pellet A) obtained from a composition containing 10 to 250 parts by weight of glass fiber to 1 part of 100 ml of polyamide resin, and 100 ml of polyamide resin.
The molding material (pellets) B) obtained from a composition containing 10 to 100 parts by weight of aluminum powder are separately produced and used as molding material when molding a molded product by injection molding. On the other hand, pellet B
This invention relates to a method for molding a molded article having a metallic appearance, characterized by using a mixture of 10 to 60 parts by weight of the following.

Examples of the polyamide resin used in the present invention include polyamide resins obtained by polycondensation of lactams or ω-amino acids having four or more membered rings, or polycondensation of dibasic acids and diamines.

Examples of the above-mentioned lactam or ω-amino acid having a four-membered ring or more include ε-caprolactam, ω-laurolactam, ω-aminocaprylic acid, and ω-aminolauric acid.

Polyamides obtained from dibasic acids and diamines include glucuric acid, adipic acid, azelaic acid, sebacic acid,
From dibasic acids such as speric acid, dodecanniic acid, eicosionic acid, isophthalic acid, and terephthalic acid, and diamines such as tetramethylene diamine, hexamethylene diamine, octamethylene diamine, metaxylylene diamine, paraxylylene diamine, and paraphenylene diamine. The resulting polymer or copolymer can be exemplified.

Specific examples of the polyamides include nylon 4, nylon 6, nylon 12, nylon 66, nylon 610, nylon 612, polymethaxylylene adipamide, polymethaxylylene adipamide, polymethaxylylene dodecamide, polyhexamethylene Examples include, but are not limited to, phthalamide and mixtures or copolymers thereof.

In the present invention, when a metaxylylene group-containing polyamide resin (hereinafter referred to as "rMX nylon") is used among the polyamides exemplified above, a molded article having fM superior performance can be obtained particularly in terms of mechanical properties, water resistance, etc. .

Among the above MX nylons, metaxylylene diamine alone or metaxylylene diamine 6 is preferable.
A diamine mixture containing 0 weight % or more and 40 weight % or less of paraxylylenediamine, and an α, ω-linear aliphatic dibasic acid having 6 to 20 carbon atoms, such as adipic acid, sebacic acid, sheric acid, dodecanoic acid. Examples include polyamide resins synthesized by a polycondensation reaction with , eicosionic acid, and the like.

Among the MX nylons, adipic acid is particularly preferred among the α,ω-linear aliphatic dibasic acids, considering the balance of moldability, molded product performance, and the like.

Furthermore, when MX nylon is used as the polyamide resin, blending nylon 66 with MX nylon has the effect of shortening the moldability of MX nylon, that is, the cycle time during molding.

In this case, the blending ratio of nylon 66 to MX nylon is effective over a wide range in terms of shortening molding time, and the blending ratio is 40 to 99% for MX nylon.
Nylon 6660 to 1 part by weight, preferably 60 to 97 parts by weight of MX nylon to nylon 664
It is 0 to 3 parts by weight.

When the blending ratio of nylon 66 is less than 1 part by weight based on the weight of MX nylon 99, the effect of improving the moldability of MX nylon is small. Further, if the blending ratio of MX nylon is 40 parts by weight or less based on 6660 parts by weight of nylon, the effect of improving mechanical strength and physical properties of water absorption B5+ becomes small.

The glass fiber used in the present invention is not particularly limited as long as it can be used as a reinforcing material for resin, and it may be either roving or chopped strand.

The above-mentioned glass fiber may be surface-untreated,
Further, it may be surface-treated with a coupling agent such as a silane coupling agent or a titanate coupling agent, but it is preferable that the surface be treated with a coupling agent.

The amount of glass fiber used in the pellets used in the present invention is 10 parts by weight per 100 parts by weight of the polyamide resin.
-250 parts by weight, preferably 20-150 parts by weight. In Pellet A, if the amount of glass fiber blended is less than 10 parts by weight with respect to 100 parts by weight of polyamide resin, the effect of modification of mechanical strength, thermal properties, etc. cannot be obtained, and the blended amount of glass fiber is 250 parts by weight or less. If it is above the star part, the gloss of the aluminum powder will be significantly reduced, which is not preferable.

The aluminum powder used in pellet B of the present invention preferably contains 80% or more of particles with a particle size of 149 μm or less, and 30% or more of particles with a particle size of 44 μm or more.

If the aluminum powder contains 70% or more of particles with a particle size of 44 μm (325 mesh) or less, a molded product with excellent gloss may not be obtained.

The particle size of aluminum powder is 149 μm (100 mesh)
If it contains 20% or more of the above, the particle size will be too large and the metallic tone will be impaired.

The aluminum powder may be aluminum foil in the form of scales, or may be atomized aluminum made by blowing molten aluminum into fine particles. Additionally, aluminum that has been surface-treated to increase its gloss can also be used.

The amount of aluminum powder used in the present invention is 10 to 10 parts by weight per 100 parts by weight of the polyamide resin of pellet B.
0 parts by weight, preferably 20 to 70 parts by weight.

If the aluminum powder is less than 10 parts by weight with respect to 100 parts by weight of the polyamide resin, a metallic tone cannot be obtained;
If the amount exceeds 1 part by weight, extrusion workability is poor and it is difficult to produce pellets.

In the present invention, when producing pellets B, aluminum powder that has been pre-wetted may also be used.

Aluminum powder is designated as Metal Powder A in Dangerous Substances Class 2 under the Fire Service Act, especially 1; Lialuminium powder has the risk of dust explosion, but when wetted with liquid, this dust explosion risk can be reduced. This results in the effect of significantly reducing the

Further, by pre-wetting the aluminum powder, the fluidity of the composition during molding can be improved.

Examples of the liquid used to moisten the aluminum powder include silicone oil, mineral spirit, toluene, and xylene, and among these, it is particularly preferable to use silicone oil.

By using silicone oil, the danger of organic solvents igniting or exploding can be greatly reduced.

When silicone oil is used in the present invention, the silicone oil used is dimethyl silicone oil,
Examples include methylphenyl silicone oil, methylhydrogen silicone oil, and various modified silicone oils.

In addition, in order to reduce the risk of ignition and explosion, the flash point of silicone oil should be 200°C or higher, preferably 300°C or higher.
°C or higher is better.

When silicone oil is used in the present invention, the amount of silicone oil used is 01 to 20 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the polyamide resin used for Pereno I-B.

If the amount of silicone oil is less than 0.1 part by weight per 100 parts by weight of the polyamide resin, it will not be possible to prevent the scattering of aluminum powder dust, and it will not be effective in improving the fluidity of the composition when it is melted. Less is.

If the blending amount of silicone oil is 20 parts by weight or more based on 100 parts by weight of polyamide resin, the silicone oil will not be compatible with the polyamide resin, the silicone oil will separate, and the molded product will become marbled, resulting in a good molded product. do not have.

The pellets used in the present invention are produced by melt-mixing using an extruder at a temperature 5 to 50°C higher than the melting point of the polyamide resin.

The polyamide resin composition of the present invention may further contain additives such as stabilizers against deterioration due to oxidation, heat, ultraviolet rays, etc., nucleating agents, plasticizers, mold release agents, lubricants, antistatic agents, and the like.

In addition, inorganic fillers such as calcium carbonate, talc, and wollastonite, potassium titanate, silicon carbide whiskers, carbon fibers, ceramic fibers, and carbon fibers may be added to the polyamide resin composition of the present invention within a range that does not impair the purpose of the present invention. Pigments such as black may also be appropriately blended.

In the present invention, when molding a molded product, 10 to 10 parts by weight of pellets B are added to 100 parts by weight of pellets A as a molding material.
It is used by mixing 60 parts by weight.

If the mixing ratio of pellets B to 100 parts by weight of Beresol I-A is less than 10 parts by weight, the amount of aluminum powder in the molded product will be small and the desired metallic appearance will not be obtained.

Furthermore, if the mixing ratio of Pellet I-B to 100 parts by weight of Pellet A is 60 parts by weight or more, the fluidity of the melt may decrease during injection molding, resulting in processing problems.

The molded product of the present invention is molded by injection molding after mixing pellets A and B in pellet form in a tumbler or the like.

Furthermore, when injection molding the polyamide resin composition of the present invention, the mold is preferably mirror-polished.

[Example] Next, the present invention will be specifically explained with reference to Examples and Comparative Examples. The methods used to measure the characteristics are as follows.

(1) Mechanical properties: Mechanical properties were determined by the following test method.

Bending strength: ASTM D70 Flexural modulus: ASTM D790 Heat distortion temperature: ASTM D648 Load: 18.5kg/cm2 (2) Glossiness of molded product: Based on visual judgment.

○: Good (the shine of the aluminum powder is beautiful) △: Slightly good (the shine of the aluminum powder is slightly visible) ×: Poor (the shine of the aluminum powder is completely absent and the color is gray) Example 1 Poly(metal) xylylene adipamide) (hereinafter referred to as ``nylon MXD-6J, manufactured by Mitsubishi Gas Chemical ■, polyamide polymer (1 g) was dissolved in 100 ml of 98% sulfuric acid, and the relative viscosity (hereinafter referred to as ``relative viscosity'') was measured at 25 ° C. ):2.1
4) 100 parts by weight, 25 parts by weight of pellets of nylon 66 (relative viscosity: 2.25), and 125 parts by weight of chopped glass fiber strands of 3 mm length (manufactured by Asahi Fiberglass 0 Kiku, trade name: C3O3JA411) Mix in a tumbler and heat to 275°C using a vented extruder.
After melt-kneading, the mixture was extruded into strings, cooled in a water bath, cut, and dried to produce pellet-shaped molding materials (pellets A).

Next, aluminum powder (manufactured by Toyo Aluminum ■, Trial Paste P-1415, particle size: 149 μm or more;
2% or less, 44 μm or more; 70° or more) 100 parts by weight of silicone oil (manufactured by Toshiba Silicone ■, TSF4)
300) was added and mixed by shaking in a polyethylene bag to prepare wet aluminum powder.

00 parts by weight of nylon MXD-6 (relative viscosity: 2.14) and 50 parts by weight of the above wet aluminum powder were placed in a tumbler.
The mixture was mixed in a vented extruder and melt-kneaded at 260''C, extruded into strings, cooled in a water bath, cut, and dried to produce pellet-shaped molding materials (pellets B).

Next, 00 parts by weight of Al pellets and 825 parts by weight of pellets were mixed in a tumbler, and the molding material was heated to a mold temperature of 130.
A molded article was obtained by injection molding at °C.

Table 1 shows the performance test results and glossiness of the molded products.

Example 2 Nylon 12 (manufactured by Ube Industries 01, UBE Nylon 3035U) was used as the polyamide resin of pellet B of Example 1,
Shiny aluminum powder which is atomized aluminum powder as aluminum powder (manufactured by Daiwa Metal Powder Industry ■, atomized aluminum product name: No. 235, particle size: 8
A molded product was obtained in the same manner as in Example I, except that the melt-kneading temperature was 220°C. The test results of this molded product are shown in Table 1.

Example 3 In Example 1, the glass fiber content of pellet A was changed to 1
A molded product was obtained in the same manner as in Example 1 except that the amount was 5 parts by weight.

The test results of this molded product are shown in Table 1.

Implementation M± The aluminum powder of pellet B in Example 1 was manufactured by Fukuda Metal Foil & Powder Industry (trade name: Niastro Flake S#5).
, particle size: 62 to 74 μm) and 100 parts by weight of dimedyl silicone (manufactured by Toshiba Silicone ■) as silicone oil.
A molded product was obtained in the same manner as in Example 1 except that 30 parts by weight of TSF-451-500) was used.

The test results of this molded product are shown in Table 1.

Example 5 A molded product was obtained in the same manner as in Example 1 except that silicone oil was not used in the pellets. The test results of this molded product are shown in Table 1.

Comparative Example 1 - A molded product was obtained in the same manner as in Example 1, except that 100 parts by weight of nylon MXD-6 (relative viscosity: 2.14) was used without blending glass fiber with pellet A of Example 1. .

The test results of this molded product are shown in Table 2.

The molded product had a low heat distortion temperature, and also had low strength and rigidity.

Comparative Example 2 Aluminum powder 100 used in pellet B of Example 1
A wet aluminum powder was prepared by adding 100 parts by weight of silicone oil to the parts by weight.

Next, nylon MXD-6 (relative viscosity: 2.14) 100
A molded product was obtained in the same manner as in Example 1, except that pellet B was produced using 100 parts by weight of the wet aluminum powder. The test results of this molded product are shown in Table 2.

Flow marks were generated on the molded product, and a good molded product could not be obtained.

Comparative Example 3 Example 1 except that Super Fine No. 18000 (particle size: 88 μm or more; 0.5% or less; 44 μm or less; 98% or more) from Daiwa Metal Powder Industry ■ was used as the aluminum powder for pellet B. A molded product was obtained in the same manner. The test results for this molded product are shown in Table 2.

The particle size of the aluminum powder was too small and lacked gloss, making it impossible to obtain a good molded product.

Comparative Example 4 As the aluminum powder of pellet B of Example 1, one made by Fukuda Metal Foil Powder Kogyo 0 Kiku (trade name Niastro Flake S) was used.
A molded product was obtained in the same manner as in Example 1 except that #40, particle size: 208 to 295 μm) was used.

The test results of this molded product are shown in Table 2.

Since the particle size of the aluminum powder was too large, a molded product with a good metallic appearance could not be obtained.

Comparative Example 5 100 parts by weight of nylon MXD-6 (relative viscosity: 2°14), 132 parts by weight of glass fiber and 32 parts by weight of the aluminum powder used in Example 1 were mixed in a tumbler, and mixed using a vented extruder. , and melt-kneaded at 275°C to obtain a pellet-shaped molding material.

This pellet-shaped molding material was injection molded to obtain a molded product.

The resulting molded product lost the luster of the aluminum powder, had a gray appearance, and did not have a metallic tone.

Table 1 Table 2 γ17n poor silicone fortress crack 1'5+1-L)I-,1)υυ
[Effects of the Invention] The molding method of the present invention makes it possible to produce a polyamide resin molded product that is reinforced with glass fiber and has an excellent metallic appearance, which was previously impossible.

Since the molded product obtained by the present invention can be reinforced with glass fiber, it has particularly excellent strength, rigidity, and heat resistance compared to conventional products, and is extremely useful.

hand Continued Supplementary Positive book (spontaneous) October 26, 1986

Claims (5)

[Claims] (1) A molding material (pellet A) obtained from a composition containing 10 to 250 parts by weight of glass fiber to 100 parts by weight of polyamide resin, and 10 to 100 parts by weight of aluminum powder to 100 parts by weight of polyamide resin. The molding materials (pellets B) obtained from the blended compositions are manufactured separately, and when molding a molded article by injection molding, 10 to 6 parts by weight of pellets B are added to 100 parts by weight of pellets A as a molding material.
A method for molding a molded product having a metallic appearance, characterized in that 0 parts by weight of the molded product is mixed. (2) The polyamide resin used for pellets A and/or pellets B is a polyamide resin 60 to 99 obtained from xylylene diamine and an α,ω-linear aliphatic dibasic acid.
The molding method according to claim (1), wherein the mixed polyamide resin is composed of 1 part by weight and 6640 to 1 part by weight of nylon. (3) Aluminum powder contains 80% or more of particles with a particle size of 149 mμ or less, and 30% of particles with a particle size of 44 mμ or more
The molding method according to claim (1), wherein the molding method is scaly or atomized aluminum containing the above. (4) A patent claim in which pellet B is a molding material (pellet B) obtained from a composition containing 100 parts by weight of polyamide resin, 10 to 100 parts by weight of aluminum powder, and 0.1 to 20 parts by weight of silicone oil. Range number (1)
Molding method described in section. (5) Molded product having a metallic appearance obtained by the molding method described in claim (1)