JP3787905B2 - Multi-layer injection molded products - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multilayer injection molded article having a metallic feeling that can be used without applying surface coating to automobiles, household electrical appliances, containers and the like.
[0002]
[Prior art and problems to be solved by the invention]
Conventionally, as an injection-molded article made of a thermoplastic resin composition imparted with a metallic feeling, a molded article obtained by injection-molding a resin composition containing a thermoplastic resin and metal particles is known. For example, Japanese Patent Application Laid-Open No. 58-37045 discloses an injection molded article made of a resin composition containing an ABS resin and metal particles selected from aluminum, copper, and a copper alloy. Japanese Patent Application Laid-Open No. 50-129651 discloses an injection-molded product comprising a resin composition containing polyester and aluminum particles containing polyethylene terephthalate or polybutylene terephthalate as main components. However, the injection-molded product made of these resin compositions has a problem that the weld line is conspicuous and the dimensional accuracy cannot be obtained. Moreover, in order to obtain the physical property according to the use of parts, the molded article which consists of the said resin composition was not enough.
[0003]
An object of the present invention is to provide a multilayer injection molded article that gives a metallic feeling only to the outermost layer of the molded article and further improves the appearance of the welded portion of the molded article.
[0004]
[Means for Solving the Problems]
As a result of intensive investigations on a multilayer injection molded product that gives a metallic feeling only to the outermost layer of the molded product and further improves the appearance of the welded portion of the molded product, the specific particle size whose surface is coated with titanium oxide is determined. It has been found that the object of the present invention can be achieved when a layer made of a resin composition containing a mineral containing a thermoplastic resin and a thermoplastic resin is used as the outermost layer, and the present invention has been completed.
[0005]
That is, the present invention contains 100 parts by weight of a polypropylene resin having a melt flow rate in the range of 10 to 100 g / 10 min and 0.01 to 1 part by weight of mica having an average particle size of 10 to 100 μm coated with titanium oxide. A multilayer injection molded product characterized in that a layer made of a polypropylene resin composition is formed as an outermost layer. Hereinafter, the present invention will be described in detail.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The titanium oxide-coated mica used in the present invention has an average particle size of 10 to 100 μm, preferably 10 to 60 μm. When the average particle size is less than 10 μm, the weld line of the molded product is easily noticeable, and when it exceeds 100 μm, the amount of irregular reflection of light is reduced by the mineral and the metallic feeling is weakened, which is not preferable. The titanium oxide-coated mica improves the appearance of the welded portion of the molded product, and gives a metallic feeling to the surface of the molded product instead of the metal particles. Examples of the method for measuring the average particle diameter of the titanium oxide-coated mica include a method in which the particle diameter having a volume ratio of 50% is used as the average particle diameter in the particle size distribution obtained by the microtrap laser diffraction method in which the particle shape is converted into a sphere. If the surface of mica is not coated with titanium oxide, irregular reflection of light by mica hardly occurs and a metallic feeling is not obtained, which is not preferable.
[0007]
The surface of mica is coated with titanium oxide, but the coverage is not particularly limited and is preferably 10 to 40%, for example. The coverage of titanium oxide with respect to mica is preferably 10 to 40%. The mica coated with titanium oxide is preferably the product name “Iriodin” manufactured by Merck Japan.
[0008]
The addition amount of the titanium oxide-coated mica is 0.01 to 1 part by weight, preferably 0.05 to 0.5 parts per 100 parts by weight of the polypropylene resin having a melt flow rate in the range of 10 to 100 g / 10 minutes. Parts by weight. If the amount added is less than 0.01 parts by weight, a metallic feeling cannot be obtained, while if it exceeds 1 part by weight, the weld line tends to be noticeable, which is not preferable.
[0009]
The outermost layer of the multilayer injection molded product of the present invention is mica 0.01 having an average particle size of 10 to 100 μm coated with 100 parts by weight of a polypropylene resin having a melt flow rate in the range of 10 to 100 g / 10 min and titanium oxide. It is formed from a polypropylene resin composition containing ˜1 part by weight. The thermoplastic resin constituting the other layers of the multilayer injection-molded product of the present invention is not particularly limited as long as normal injection molding is possible. Examples of the thermoplastic resin include polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyamide, polycarbonate, polyphenylene ether, polymethyl methacrylate, acrylonitrile-butadiene-styrene copolymers, modified products thereof, and polymer alloys. The at least 1 sort (s) of thermoplastic resin chosen is mentioned. Among these, a polypropylene resin having a gloss value of 70% or more and a melt flow rate in the range of 10 to 100 g / 10 minutes, or a resin composition containing the polypropylene resin is preferable.
[0010]
The multilayer injection molded product of the present invention preferably has a gloss value of 70% or more. The gloss value can be measured with a GM-3M gross meter manufactured by Murakami Color Research Laboratory at a measurement angle of 60 °. Further, the melt flow rate can be measured based on the method specified in JIS-K-7203, at a measurement temperature of 230 ° and a load of 2.16 kg.
[0011]
The thermoplastic resin is most desirably one having a melt viscosity equivalent to or slightly lower than that of the layer material other than the outermost layer.
[0012]
The multilayer injection-molded product of the present invention comprises a layer composed of a resin composition containing a polypropylene resin having a melt flow rate in the range of 10 to 100 g / 10 min and titanium oxide-coated mica, that is, a molded product. What is necessary is just to comprise in the surface layer by the side of the design surface of goods.
[0013]
The layers other than the outermost layer in the multilayer injection molded product of the present invention are not particularly limited as long as they can be melt-bonded to the material constituting the outermost layer. For example, a thermoplastic resin or a thermoplastic resin composition Is used. As a thermoplastic resin or a thermoplastic resin composition, for example, when a resin composition containing a polypropylene resin in the outermost layer is selected, a polypropylene resin, a polypropylene resin composition containing a recycled material, an olefin elastomer, etc. may be mentioned. .
[0014]
Moreover, the thermoplastic resin or thermoplastic resin composition used for the outermost layer or other than the outermost layer of the multilayer injection-molded product is usually used as necessary, such as an antioxidant, an ultraviolet absorber, a flame retardant, and a colorant. Various additives may be contained.
[0015]
The molding method of the multilayer injection molded product of the present invention is not particularly limited, and examples thereof include a multilayer molding method, a multicolor injection molding method, and a sandwich molding method.
[0016]
【Example】
EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, this invention is not limited to these Examples.
[0017]
The injection molding machine, molded product shape, mold and evaluation method used in the examples and comparative examples are as follows.
(1) Injection molding machine FS160S25ASEN made by Nissei Plastic, molding temperature: 230 ° C
(2) Shape of molded product It is a sandwich molded product composed of outer layer / inner layer / outer layer. The ratio of the outer layer material to the inner layer material in the molded product is 4/5 in terms of injection volume ratio, and the ratio of the thickness of the outer layer piece side to the molded product thickness is 0.08 near the gate with respect to the total thickness of the molded product, and the center Part was 0.15, and the flow end part was 0.22.
(3) Mold A mold having a molded product size of 100 mm × 400 mm × 3 mm flat plate, which is a mold in which both sides of the mold are polished and finished by plating No. 1000. The mold surface temperature at the time of molding was 45 ° C. The weld line was evaluated by generating a weld line by attaching a 20 mm × 20 mm × 2.5 mm aluminum plate to the center of the mold with a double-sided tape.
[0018]
(4) Gloss
The central part of the molded product was cut out as a 50 mm square test piece, and measured with a GM-3M gloss meter manufactured by Murakami Color Research Laboratory at a measurement angle of 60 °.
(5) Metallic feeling The molded product was visually evaluated as follows.
○ A moderate metallic feeling is obtained.
× There is no metallic feeling at all.
(6) Weld part The molded article was visually evaluated as follows.
○ The weld line is not noticeable.
△ Weld line can be seen depending on viewing angle.
× The weld line is conspicuous.
(7) Melt flow rate Based on the method prescribed | regulated to JIS-K-7203, measurement temperature was 230 degreeC and the load was measured as 2.16 kg.
[0019]
Example 1
A group colored by adding 0.2 parts by weight of carbon black to 100 parts by weight of an ethylene-propylene random copolymer (manufactured by Sumitomo Chemical Co., Ltd., registered trademark Sumitomo Nobrene “Z144A”, MFR = 27 g / 10 min). A resin composition obtained by adding 0.05 parts by weight of mica (trade name Iriodin 153, manufactured by Merck Japan Ltd.) having an average particle size of 60 μm with a titanium oxide coverage of 16% to the material is used as both outer layer materials. A sandwich injection molded article in which a resin composition containing 20% by weight of talc in a polymer (manufactured by Sumitomo Chemical Co., Ltd., registered trademark Sumitomo Noblen “BWA52A”, MFR = 15 g / 10 min) is arranged as an inner layer material was obtained. . The evaluation results are shown in Table 1.
[0020]
Example 2
A sandwich injection-molded product was obtained in the same manner as in Example 1, except that 0.1 part by weight of the same titanium oxide-coated mica (trade name: Iriodin 153, manufactured by Merck Japan) used in Example 1 was added. The evaluation results are shown in Table 1.
[0021]
Example 3
A sandwich injection-molded product was obtained in the same manner as in Example 1 except that 0.5 part by weight of the same titanium oxide-coated mica (trade name: Iriodin 153, manufactured by Merck Japan) used in Example 1 was added. The evaluation results are shown in Table 1.
[0022]
Example 4
Instead of the titanium oxide-coated mica used in Example 1, 0.5 parts by weight of mica having a titanium oxide coating ratio of 30% and an average particle size of 20 μm (trade name Iriodin 103, manufactured by Merck Japan) was added. A sandwich injection molded product was obtained in the same manner as in Example 1. The evaluation results are shown in Table 1.
[0023]
Comparative Example 1
Sandwich similar to Example 1 except that 0.5 parts by weight of aluminum powder (TPK13UK manufactured by Toyo Aluminum Co., Ltd.) having an average particle size of 35 μm was added instead of the titanium oxide-coated mica used in Example 1. An injection molded product was obtained. The evaluation results are shown in Table 1.
[0024]
Comparative Example 2
Instead of the titanium oxide-coated mica used in Example 1, except that 0.5 parts by weight of mica having an average particle size of 10.5 μm (a Chinese wet pulverized product, mica not coated with titanium oxide) was added, A sandwich injection molded product was obtained in the same manner as in Example 1. The evaluation results are shown in Table 1.
[0025]
Comparative Example 3
Instead of the titanium oxide-coated mica used in Example 1, mica having an average particle size of 74 μm (indian wet pulverized product, mica not coated with titanium oxide) was added in an amount of 0.5 parts by weight. In the same manner as in No. 1, a sandwich injection molded product was obtained. The evaluation results are shown in Table 1.
[0026]
[Table 1]
───────────────────────────────
Example Comparison example
1 2 3 4 1 2 3
───────────────────────────────
Gross% 90 90 89 89 90 88 88
Metallic feeling ○ ○ ○ ○ ○ ○ ×
Weld part ○ △ △ △ × × ○
───────────────────────────────
[0027]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to provide a multilayer injection-molded product that imparts a metallic feeling only to the outermost layer portion of the molded product and improves the appearance of the welded portion of the molded product. In addition, since the present invention imparts a metallic feeling, it is not necessary to apply a surface coating, and a multilayer injection molded product with reduced component costs can be provided. Furthermore, the multilayer injection-molded product of the present invention is suitable for automobiles, home appliances, containers and the like.

Claims (3)

Polypropylene resin composition having an average particle diameter of the melt flow rate is coated with polypropylene resin 100 parts by weight of titanium oxide in the range of 10 to 100 g / 10 min is contained 0.01 to 1 part by weight mica 10~100μm A multilayer injection-molded product comprising a layer made of A three-layer multilayer injection-molded article comprising both outer layers and an intermediate layer, wherein both outer layers are coated with 100 parts by weight of a polypropylene resin having a melt flow rate in the range of 10 to 100 g / 10 min and titanium oxide. 2. The layer comprising a polypropylene resin composition containing 0.01 to 1 part by weight of mica having a particle size of 10 to 100 [mu] m, and the intermediate layer is a layer comprising a polypropylene resin. Multi-layer injection molded product. The multilayer injection-molded article according to claim 2, wherein the melt viscosity of the polypropylene resin contained in the polypropylene resin composition constituting both outer layers is equal to or lower than the viscosity of the polypropylene resin constituting the intermediate layer.