JPH09194630A - Metallic pigment comprising polyhedral particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an injection molded article prevented from the occurrence of weld when blended with a resin and melt molded and having a metallic surface. SOLUTION: This pigment comprises polyhedral particles having a mean particle diameter of 10-300μm, a mean aspect ratio (breadth/length) of 1/(3 to 1), and a metal coating of 100-1,000Å in thickness on the surfaces. Examples of preferable polyhedral particles used include those comprising oxide glasses, such as silica glass, alkali silicate glass, soda-lime glass, lead glass, barium glass and borosilicate glass. The surfaces of the polyhedral particles are coated by, e.g., sputtering with Au, Ag, Cu, Al or an alloy thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pigment capable of preventing a weld, which is likely to occur during molding of a plastic molded product, and imparting a metallic feeling.

[0002]

2. Description of the Related Art Plastic moldings having a metallic appearance are manufactured using metallic pigments such as aluminum flakes, mica, pearl mica, mica-like iron oxide, glass flakes and stainless flakes. For example, in the coating method, a metallic pigment is mixed with a paint and the paint is applied to the surface of a molded article. In the melt molding method, a composite in which a metallic pigment is mixed with a resin is melt molded. Since the coating method requires a complicated coating process, it is troublesome and costly. On the other hand, the melt molding method is a preferable method because it does not require a coating process, but it is difficult to obtain a high-grade metallic-like molded product having a depth as compared with the coating method. In order to obtain high-quality metallic products by the melt molding method, it is necessary to add a large amount of metallic pigments, which impairs the original properties of the resin and adversely affects dispersibility, coating properties, etc. become. In addition, as the amount of the metallic pigment mixed is increased, welds are more likely to occur during plastic molding, and the appearance of the product is significantly impaired. by the way,
JP-A-4-359937, JP-A-5-1710, JP-A-5-179174, and JP-A-5-32.
As shown in Japanese Patent No. 0588, new metallic pigments having a strong glittering feeling are being developed one after another.
These metallic pigments are produced by coating glass flakes having a smooth surface with a thin film of gold, silver, nickel, titanium nitride or the like by electroless plating, vacuum deposition, sputtering or the like. Although all of them can give an excellent metallic feeling, they have no effect in preventing the occurrence of welds and cannot be used in the melt molding method of plastics.

[0003]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention As an effect for preventing the occurrence of welds, gloss particles and metal particles having an average particle size of 35 μm to 1 mm and an average aspect ratio of 1/8 to 1 are disclosed in Japanese Patent Publication No. 4-27932. Japanese Patent Publication No. 4-55462, Japanese Patent Publication No. 6-99592, Japanese Patent Publication No. 6-9959.
It is introduced in the publication No. 4 and the like. Also, JP-A-62-15
In 6164, a bead material having a glossy coating is also introduced as being effective in preventing the occurrence of welds. However, none of these additive materials actually has sufficient performance for preventing the occurrence of welds and imparting a metallic feeling. Therefore, in order to give a sufficient metallic feeling, the amount added to the resin must be increased, and as a result, the generation of welds is promoted. On the other hand, if the addition amount is reduced, welds are less likely to occur, but a metallic feeling can hardly be imparted. Therefore, there is a demand for further improvement in coating technology for imparting particle shape and gloss. The present invention has been devised in order to meet such a requirement, and by coating a metal on angular polyhedral particles, a new addition that can prevent weld during melt molding and impart an excellent metallic feeling The purpose is to provide wood.

[0004]

In order to achieve the object, the metallic pigment of the present invention has an average particle size of 10 to 30.
0 μm, average aspect ratio of shortest diameter / longest diameter is 1 to
The surface of the polyhedral particle 1 is coated with a metal having a thickness of 100 to 1,000Å. As the polyhedral particles, for example, glass such as elemental glass, hydrogen-bonded glass, oxide glass, fluoride glass, chloride glass, sulfide glass, carbonate glass, nitrate glass, and sulfate glass can be used. From the viewpoint of price, oxide glass such as silicate glass, alkali silicate glass, soda lime glass, lead glass, barium glass and borosilicate glass is preferable. The surface of the polyhedral particles is coated with Au, Ag, Cu, Al or an alloy thereof by a sputtering method or the like.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Polyhedral particles have an average particle size of 10 to 300.
Those having an average aspect ratio of 1/3 to 1 are used. If the average particle size is less than 10 μm, the color tone becomes grayish black after applying the metal coating, and almost no metallic feeling can be imparted. It is presumed that this is due to the lack of the reflective smooth surface. Conversely, 3
With an average particle size of more than 00 μm, a fine metallic feeling cannot be imparted unless the mixing amount is considerably increased. Also, the cost is high. Generally, 50-
Most preferred is an average particle size of 150 μm. The shape of the polyhedral particles is an important factor that affects both the prevention of welds and the metallic appearance. In order to prevent the occurrence of welds, it is necessary to eliminate the directionality of the particles to eliminate the orientation of the particles due to the flow of the resin, and to similarly reflect the light from any direction. Spherical or bead-shaped particles are not effective in preventing the occurrence of welds and improving the metallic feel.

In this respect, in the present invention, the average aspect ratio of the particles is 1/3 to 1. Average aspect ratio is 1 /
If it is less than 3, the particles tend to be oriented, and the amount of light reflected varies depending on the orientation direction, so that the occurrence of welds cannot be prevented. Further, it is necessary that the polyhedron has a plurality of light-reflecting surfaces so that light is similarly reflected from any direction. Polyhedral particles having two or more light-reflecting surfaces, preferably four or more, are effective. However, when the number of light reflecting surfaces is 12 or more, the area of each surface becomes small, and a sufficient metallic feeling may not be obtained. Therefore, the light reflecting surface has 2 to 12 surfaces, preferably 4 to 12 surfaces. The light-reflecting surface is not particularly limited to a specific shape, but in order to obtain a sufficient metallic feeling, each surface is preferably a smooth surface so as to reflect light.

When the glass powder is used as the polyhedral particles, the glass powder is mechanically crushed by a ball mill, a jet mill, an attritor, a sand mill, a sample mill or the like, and then a powder having a predetermined particle size is classified by a sieve. When crushing the glass powder, it is important that the surface of the glass particles is not damaged as much as possible, the corners are not rounded into a spherical shape, and the yield of the powder having a predetermined particle diameter is high. Therefore, in order to produce the polyhedral particles suitable for the present invention, a method in which mechanical pulverization and classification by a sieve are repeatedly carried out continuously is adopted. That is, when the powder crushed to a predetermined size is taken out of the crusher as soon as possible, the surface of the glass powder is not easily scratched, the corners are not rounded, and a powder having a predetermined particle size can be obtained with good yield. The metal coated on the surface of the polyhedral particles is not limited in material as long as it can be coated with a uniform film thickness, and Au, Ag, C
u, Al or alloys thereof are used. Above all,
Ag exhibits the most excellent light reflection property.

For the metal coating, electroless plating, vacuum deposition, sputtering or the like can be adopted. Among them, the powder sputtering method developed by the present inventors is optimal. In general, the thicker the coating, the larger the surface irregularities, and the lower the glitter. For example, in electroless plating, the surface of the powder cannot be uniformly coated unless it is coated to a thickness of 1,000 Å or more. On the other hand, in the powder sputtering method, the entire surface of the powder can be uniformly coated even at 1,000 Å or less, so that it is possible to impart more excellent glitter. As a result, the amount of Ag coating, for example, can be reduced, and the manufacturing cost can be reduced. The reason why the surface of the polyhedral particles can be uniformly coated with a small amount of Ag by the powder sputtering method is that Ag atoms excited up to the plasma state repeatedly collide with the surface of the polyhedral particles at a high speed. It is presumed that the density is extremely high.

On the other hand, in the electroless plating, the surface of the polyhedral particles is preliminarily activated with Pd or the like as a pretreatment. The place where Pd adheres becomes a nucleus generation point of film formation during electroless plating. However, since Pd is attached due to a physical adsorption phenomenon, the attachment density of Pd is presumed to be considerably smaller than the collision density of Ag atoms excited into a plasma state by the powder sputtering method. As a result, the formed Ag coating is less uniform than the powder sputtering method. When a metal is coated on the surface of the polyhedral particles by the powder sputtering method, for example, an apparatus for rotating the powder-containing rotary container developed by the present inventors to sputter metal on the fluidized powder (JP-A-2-153068), An apparatus (Japanese Patent Laid-Open No. 62-250172) that sputters metal in a repeatedly falling stream of powder is used. After uniformly coating the surface of the glass flakes with a metal by the sputtering method, stearic acid, oleic acid, etc. are added to improve the dispersibility in the paint, the adhesion to the resin, the discoloration of the coating film and the corrosion resistance. The surface may be treated with various chelating agents such as various fatty acids, benzotriazole, and triazinethiol, or various coupling agents. Specific examples of the coupling agent include γ-aminopropyltriethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, vinyltriethoxysilane and γ-.
Methacryloxypropyltrimethoxysilane, titanium-based coupling agents, zirconia-based coupling agents, aluminum-based coupling agents and the like can be mentioned. The metal-coated polyhedral particles are mixed, for example, in an amount of 0.1% by weight or more, and preferably 0.5% by weight or more with respect to the thermoplastic resin. If this mixing amount is too small, it becomes difficult to obtain a deep and high-grade metallic feeling. The upper limit of the mixing amount is not particularly limited, but is appropriately set depending on the type of resin, required physical properties of the molded product, and the like. Normally,
Up to 20% by weight, preferably up to 5% by weight, of polyhedral particles are incorporated into the thermoplastic resin.

The resin with which the polyhedral particles are blended is not particularly limited as long as it is a moldable thermoplastic resin. For example, polyethylene, polypropylene, ABS, AES, AS, acrylic, polystyrene, polymethylpentene, polyamide, polyethylene terephthalate, polyarylate, polyacetal, polycarbonate, polyphenylene ether, polysulfone, polyphenylene sulfide, polyether sulfone, polybutadiene, etc. Polymer copolymers,
There are mixtures and modified products. In particular, AS resin, acrylic,
A highly transparent resin such as polystyrene or polycarbonate is preferable. A resin colored with a dye or a pigment can also be used. When coloring with a small amount of carbon black or phthalocyanine blue, a deeper metallic tone can be imparted. The resin containing the polyhedral particles is
It is mixed with a tumbler, a blender, a Nauter mixer, a Banbury mixer, a kneading roll and the like, and melt-molded into a predetermined shape with an extruder, an injection molding machine and the like. At this time, a stabilizer, a dispersant, an ultraviolet absorber, a release agent, etc. may be added within a range that does not impair the weld prevention effect and metallic feel.

[0011]

【Example】

Example 1 Transparent glass particles of soda-lime glass having an average particle size of 10 μm and an average aspect ratio of ½ were coated with Au to a thickness of 100 Å using the powder sputtering apparatus shown in FIG. In this powder sputtering apparatus, a rotating drum 1 having an inner diameter of 200 mm and an axial length of 200 mm is supported by two rolls 2, and one of the rolls 2 is a drive roll rotated by a motor 3. Two sputtering sources 4 are arranged inside the rotary drum 1. The sputtering source 4 is equipped with a magnetron having a target of 99.9 wt% Au and a frequency of 13.56 MHz and an output of 1.5 KW, and Au is sputtered on the introduced transparent glass particles 5.

A decompression processing chamber 7 having a heating coil 6 on the outer periphery is arranged above the rotary drum 1. The bottom of the decompression processing chamber 7 is connected to the rotary drum 1 by a supply pipe 9 equipped with a valve 8. It is connected. An Ar gas introduction pipe 10 is inserted inside the supply pipe 9 below the valve 8. The Ar gas introducing pipe 10 has a double pipe structure, is inserted inside from the side surface of the rotary drum 1, and has a tip extending to the bottom of the rotary drum 1. Branch pipe 11 below valve 8 of supply pipe 9
Is provided, and the tip of the branch pipe 11 is connected to the fluid jet mill 12. The outlet side of the fluid jet mill 12 is connected to the upper part of the decompression processing chamber 7 via the circulation pipe 13. The branch pipe 11 and the circulation pipe 13 have valves 14 and 1
5 are provided respectively, and a solid-gas separation device 16 is connected to the circulation pipe 13.

100 parts of transparent glass particles 5 are placed on the rotary drum 1.
g, and the decompression chamber 7 was decompressed to 3.0 × 10 ⁻³ Pa, and then Ar gas was introduced from the Ar gas introduction pipe 10 at 15 cm ³ /
Introduced at a flow rate of minutes, transparent glass particles 5 are passed through a branch pipe 11, a fluid jet mill 12 and a circulation pipe 13 to form a decompression treatment chamber 5
It was sucked and transferred to. Then, in the decompression processing chamber 7, the heating coil 6
Was heated to 200 degrees for 30 minutes to dry and degas the transparent glass particles 5. Next, the atmosphere of the rotating drum 1 is set to A.
After completely substituting with r gas, the transparent glass particles 5 in the decompression chamber 7 are dropped from the supply pipe 9 into the rotary drum 1,
While rotating the rotating drum 1 at a rotation speed of 5 rpm,
Sputtering was performed by the sputtering source 4 under a reduced pressure of 3.0 × 10 ⁻¹ Pa. After 10 minutes, the sputtering was stopped, the decompression chamber 7 was decompressed, the Ar gas was introduced into the rotary drum 1 from the Ar gas introduction pipe 10, and the transparent glass particles 5 were sucked and returned to the decompression chamber 7 via the fluid jet mm12. Then, the transparent glass particles 5 agglomerated during the sputtering were loosened into particles. The transparent glass particles 5 returned to the decompression processing chamber 7 were covered with Au having a thickness of 10Å. By repeating this sputtering operation 10 times, the coating thickness of Au was set to 100 Å, and then recovered from the solid-gas separation device 16.

Example 2 By the same procedure as in Example 1, Cu was added to the surface of transparent glass particles of soda-lime glass having an average particle size of 50 μm and an average aspect ratio of 1 / 1.5 to a thickness of 300 Å. Coated. Example 3: In the same procedure as in Example 1, the surface of transparent glass particles of soda-lime glass having an average particle size of 100 μm and an average aspect ratio of 1/3 was coated with Ag to a thickness of 500 Å. The results of observing the surface of the Ag-coated transparent glass particles with an electron microscope are shown in FIGS. Example 4: By the same procedure as in Example 1, brass was coated on the surface of transparent glass particles of soda-lime glass having an average particle diameter of 150 μm and an average aspect ratio of 1 so as to have a thickness of 700 Å. Example 5: By the same procedure as in Example 1, the surface of transparent glass particles of soda-lime glass having an average particle diameter of 300 μm and an average aspect ratio of 1 was coated with Al to a thickness of 900 Å.

Comparative Example 1: By the same procedure as in Example 1, soda-lime glassy material having an average particle size of 5 μm and an average aspect ratio of 1
The surface of the transparent glass particles was coated with Ag to a thickness of 50Å. Comparative Example 2: By the same procedure as in Example 1, the surface of transparent glass particles of soda-lime glass having an average particle diameter of 400 μm and an average aspect ratio of ⅕ was coated with Ag to a thickness of 2,000 Å. Comparative Example 3: Soda-lime glass with an average particle size of 100 μm,
50Å on the surface of transparent glass particles with an average aspect ratio of 1.
The Ag electroless plating was performed so as to have a thickness of. In electroless plating, stannous chloride 20 g / l, hydrochloric acid 20 g / l
After 1 kg of transparent glass particles was added to 1 liter of an aqueous solution containing ## STR3 ## and the mixture was stirred at 60 ° C. for about 20 minutes for sensitizing, the transparent glass particles were thoroughly washed with deionized water.
Next, transparent glass particles were put into 1 liter of an aqueous solution containing 1 g / l of palladium chloride and 10 g / l of hydrochloric acid, and stirred at room temperature for about 20 minutes. After this activation treatment, it was washed again with deionized water, and then electroless Ag plating was performed using the following two types of solutions.

(1) Preparation of Ag ammonia solution: 4 g of silver nitrate was added and dissolved in 50 ml of deionized water, and a solution of 2 g of potassium hydroxide dissolved in 50 ml of deionized water was mixed with this. The resulting solution tended to gradually turn brown. Further, add about 40 ml of ammonium hydroxide,
The solution was stirred until the color became clear. (2) Preparation of reducing solution: 9 g of table sugar was added to 100 ml of deionized water and dissolved. About 2 ml of concentrated nitric acid was added to this solution, and the resulting solution was boiled for another 30 minutes to convert table sugar into invert sugar. Then, the reducing solution was prepared by cooling the solution to room temperature. 1 Kg of pretreated transparent glass particles was added to 150 ml of silver ammonia solution, and 110 ml of the reducing solution was added at a slow rate of 25 drops / min while stirring the bath at room temperature to perform electroless silver plating on the transparent glass particles. gave. After the silver plating was completed, the transparent glass particles were thoroughly washed with water and dried. This allows
An Ag film having a thickness of 50Å was formed on the surface of the transparent glass particles.

Comparative Example 4 In the same manner as in Comparative Example 3, the surface of transparent glass particles made of soda-lime glass and having an average particle size of 100 μm and an average aspect ratio of 1 was electroless of Ag so that the thickness was 2,000 Å. It was plated. Using the samples obtained in each of the above examples, polystyrene resin (Denka Styrol GP-1 manufactured by Denki Kagaku Kogyo Co., Ltd.) 98.
9% by weight, 1.0% by weight of the sample obtained in each example and dye pigment (Lionol blue manufactured by Toyo Ink Co., Ltd.)
A composition having a composition of 0.1% by weight was prepared.
This composition was extruded with an extruder (VSK-30 manufactured by Nakatani Co., Ltd.) at a cylinder temperature of 200 ° C. to be pelletized. From these pellets, using an injection molding machine (Nestal Cycap 480/150 manufactured by Sumitomo Heavy Industries, Ltd.), cylinder temperature 200 ° C, mold temperature 50 ° C, thickness 2 mm, width 50 mm, length 50 m.
m test plate was molded.

The weld resistance and metallic feel of the obtained test plate were visually observed. As can be seen from the observation results in Table 1, with the glass particles according to the present invention blended,
It was excellent in both weld prevention and metallic feeling.
On the other hand, in Comparative Example 1 in which transparent glass particles thinly coated with Ag were mixed with particles having a small average particle size, both the weld prevention property and the metallic feeling were inferior. Further, in Comparative Example 2 in which transparent glass particles having a large average particle size and thick Ag coating were mixed, although a metallic feeling was good, welds frequently occurred. Electroless Ag
In the case where the plated glass particles were blended, as is clear from the comparison between Comparative Example 3 and Comparative Example 4, when the Ag coating became thicker, the metallic feeling was improved, but in any case, the weld prevention property was poor.

[0019]

[0020]

Industrial Applicability As described above, the metallic pigment of the present invention is blended with a thermoplastic resin or the like to prevent weld when producing a molded article by a melt molding method, and has an excellent metallic surface. To the molded product. Therefore, plastic moldings for automobile parts such as bumpers, radiator grills, marks, wheel covers, door mirrors, door handles, cameras, OA equipment, electric razors, hair dryers, televisions, mobile phones, audio equipment, air conditioners, unit baths. It is used in a wide range of fields to manufacture injection molded products for home electric appliances.

[Brief description of the drawings]

FIG. 1 Powder sputtering apparatus used in Examples

2 is an electron micrograph (125 ×) of the surface of Ag-coated transparent glass particles in Example 3. FIG.

3 is an electron micrograph (600 times) of the surface of the transparent glass particles coated with Ag in Example 3. FIG.

FIG. 4 An electron micrograph (1250 times) of the surface of the transparent glass particles coated with Ag in Example 3.

[Explanation of symbols]

1 rotating drum 2: roll 3: motor 4: sputtering source 5: transparent glass particles 6: heating coil 7: decompression processing chamber 8: valve 9: supply pipe 10: Ar gas introduction pipe 11: branch pipe 12: fluid jet mill 13 : Circulation pipe 1
4: Valve 15: Valve 16: Solid-gas separation device

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Shirai Yasushi 7-1 Takaya Shinmachi, Ichikawa City, Chiba Nisshin Steel Co., Ltd. Technical Research Institute (72) Takashi Kurata, Kawajiri Town, Yokkaichi, Mie 100 Japan Synthetic Rubber Co., Ltd. In-house (72) Inventor Fusami Kitada 100 Kawajiri-cho, Yokkaichi-shi, Mie Japan Synthetic Rubber Co., Ltd.

Claims (3)

[Claims] 1. A metallic material having an average particle diameter of 10 to 300 μm and a surface of polyhedral particles having an average aspect ratio of the shortest diameter / the longest diameter of 1/3 to 1 coated with a metal having a thickness of 100 to 1,000 Å. Toning pigment. 2. A metallic pigment in which the polyhedral particles according to claim 1 are glass. 3. The metal coating according to claim 1 is A
A metallic pigment which is u, Ag, Cu, Al or an alloy thereof.