JP2002347062A - Metal insert-resin composite molded article and molding method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily mold a metal insert-resin composite molded article having high airtightness between a metal insert and a resin. SOLUTION: The surface of a metal component is processed beforehand to be specular so that the surface roughness be 2.5 μm or less when expressed by a ten-point surface roughness (Rz). Then, the metal component is inserted into a mold of an injection molding machine, and injection molding is executed by using a thermoplastic resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding a metal insert-resin composite molded article by insert injection molding a metal part having a mirror-finished surface using a thermoplastic resin, and an airtightness obtained by the molding method. The present invention relates to a highly insertable metal insert-resin composite molded product.

[0002]

2. Description of the Related Art As a metal insert / resin composite molded product, a metal insert such as a boss or a screw is set in a mold at the time of molding, and then the metal component is inserted into the resin molded product by injection molding. -Resin composite moldings are commonly used. In the insert molding method, the molding method is relatively simple, and the obtained metal insert-resin composite molded product prevents the strength and loosening during use because the metal component is held relatively firmly in the resin molded product. However, sufficient airtightness is not always obtained.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide easily a metal insert-resin composite molded article having high airtightness between a metal insert and a resin.

[0004]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a metal part whose surface has been mirror-finished in advance is inserted into a mold of an injection molding machine and injection-molded using a thermoplastic resin. It has been found that such a problem can be solved, and the present invention has been completed.

That is, a first aspect of the present invention is a method for molding a metal insert-resin composite molded product in which a metal component is inserted into a resin, wherein the surface of the metal component is mirror-finished in advance.
Next, there is provided a method for molding a metal insert-resin composite molded product, which comprises inserting the metal component into a mold of an injection molding machine and performing injection molding using a thermoplastic resin. A second aspect of the present invention is the metal insert-resin composite according to the first aspect of the present invention, wherein the surface roughness of the metal component after mirror finishing is 2.5 μm or less, expressed as ten-point surface roughness (Rz). Provided is a method for molding a molded article. A third aspect of the present invention provides the method for molding a metal insert-resin composite molded product according to the first or second aspect of the present invention, wherein the mirror finishing is a physical method. A fourth aspect of the present invention provides the metal insert-resin composite molding method according to the third aspect of the present invention, wherein the physical method utilizes sandpaper, blue powder or diamond paste. A fifth aspect of the present invention is the first aspect of the present invention, wherein the thermoplastic resin is mainly composed of at least one resin selected from the group consisting of polyacetal, aromatic polyester, polyphenylene sulfide, polyamide, and liquid crystalline polyester. The present invention provides a method for molding the metal insert-resin composite molded article as described above. A sixth aspect of the present invention provides a metal insert-resin composite molded article formed by the method for producing a metal insert-resin composite molded article according to any one of the first to fifth aspects of the present invention. According to a seventh aspect of the present invention, there is provided the metal insert-resin composite molded product according to the sixth aspect of the present invention, wherein the airtightness between the metal component and the resin is 1.5 MPa or more. According to an eighth aspect of the present invention, there is provided the metal insert-resin composite molded product according to the sixth or seventh aspect of the present invention, wherein the body part of the metal part embedded in the resin has a cylindrical part.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The shape of a metal part for an insert used in the present invention is not particularly limited, and examples thereof include various knurl inserts, bosses, and inserts such as screws. Examples of the shape of the screw and the like include a columnar shape, a prismatic shape, a tubular shape, a square tubular shape (nut shape), and the like. In order to obtain a highly airtight metal insert-resin composite molded product, it is desirable to have a cylindrical portion or a cylindrical portion. The metal part may have a flange on the periphery of the body part embedded in the resin. For example, in the case of a cylindrical metal insert-resin composite molded product, the flange portion may be provided on a part of the outer periphery of the circular tube, but is preferably 36.
0 °. The flange portion may be provided in one stage, but may be provided in two or more stages or in multiple stages. When the body part of the metal part is cylindrical or tubular, the outer peripheral shape of the flange part may be a circle, but a polygon or a part thereof is cut out,
By taking a shape such as to make a business trip, loosening due to rotation may be prevented. The flange portion may be provided at a right angle to the body portion, may be provided at an angle, or may be provided in a spiral shape. The connecting portion between the flange portion and the body portion may be connected smoothly with R or may be connected at an angle such as a right angle. The height of the flange is not particularly limited, and depends on the purpose and dimensions of the molded product.
Above, or 1 mm or more, or even 10 mm or more. The entire flange portion may be embedded in the resin, or a part of the flange portion may be embedded.

The material of the metal part for the insert used in the present invention is not particularly limited, and examples thereof include aluminum, iron and stainless steel. When used in applications where the temperature difference is large, these metal materials should be selected from those with a small difference in thermal expansion with the resin described later so as to prevent cracks from occurring near the boundary between the resin and the metal. Is preferred.

In the present invention, it is important that the surface of the metal part is mirror-finished in advance. The surface roughness of the metal part after the mirror finishing is represented by ten point surface roughness (Rz),
It is 2.5 μm or less, preferably 0.5 μm or less. When the surface roughness Rz exceeds 2.5 μm, the airtightness is reduced.

The mirror finishing of the surface includes a physical method such as polishing, a chemical method such as plating, and a mixing method thereof, but the physical method is preferable in terms of cost. Examples of the physical method include honing finishing by pressing a grindstone piece, similar super finishing, lap finishing using free abrasive grains, and jet finishing using free abrasive grains via a fluid. Polishing stones (for traverse polishing and plunge polishing); polishing cloth, buff or sandpaper; blue powder or diamond paste; diamond for air blast or liquid blast, alumina, silicon carbide,
Abrasive grains such as sand are included.

The mirror-finished surface is the entire part or a part of the metal part buried in the resin, and part or all of the body part to be buried, the flange surface, the side surface or the whole surface of the flange part, and the body part and the flange. Both parts are illustrated.

As the resin used in the present invention, a thermoplastic resin or a thermosetting resin can be used, but a thermoplastic resin is preferable. Examples of the thermoplastic resin include, but are not particularly limited to, polyolefins such as polyethylene and polypropylene, general-purpose resins such as polystyrene and polyvinyl chloride; and polyethylene terephthalate and aromatic or biodegradable resins such as polybutylene terephthalate. Examples include aliphatic polyesters, polyamides, polycarbonates, polyacetals, liquid crystalline polymers, engineering plastics such as polyphenylene ether and polyphenylene sulfide, and rubbers and elastomers such as celluloses. These can be used in combination. Preferably, polyacetal,
Aromatic polyester, polyphenylene sulfide, polyamide, and liquid crystalline polyester. In the present invention, these preferred resins are the main components, and other resins may be added as a small component. As other resins,
The above-mentioned thermoplastic resin is exemplified. A resin additive can be added to these resins as needed. As resin additives, heat stabilizers, antioxidants, ultraviolet stabilizers, antistatic agents, fillers, colorants, flame retardants, lubricants, antiblocking agents, nucleating agents, plasticizers, antibacterial agents, deodorants, or These mixtures are mentioned.

The insert molding method is not particularly limited, but a known injection molding method can be used. The insert molding machine is not particularly limited, and for example, a vertical injection molding machine can be used. The insert may be preheated before setting it in the mold, or may be provided with an adhesive layer by application.

[0013]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples.

As an insert metal part, an aluminum flanged cylindrical rod shown in FIG. 1 was produced. (Preparation Examples 1 and 2) Five pieces (n = 5) of each of the above aluminum rods were subjected to mirror finishing using blue powder to the two types of surface roughness shown in Table 1. The surface roughness was measured by a surface roughness / contour measuring instrument (Surftest SV-C624) manufactured by Mitutoyo. Table 1 shows the results.

(Examples 1 and 2) Next, the above-mentioned mirror-finished aluminum rod was inserted into a mold of an injection molding machine, and straight-chain polyphenylene sulfide resin FORTRON (registered trademark) 6165 (inorganic filling) was used. Injection molding was performed under the following conditions using a 65% material (manufactured by Polyplastics Co., Ltd.) to obtain a metal insert-resin composite molded article as shown in FIG. Injection molding machine: Sodick TR40VR Injection molding conditions Resin temperature: 320 ° C Mold temperature: 150 ° C Injection speed: 3 m / min (Evaluation of airtightness of molded product) As shown in FIG. It was set in a pressure vessel with packing interposed, and airtightness was evaluated by a water pressure tightness test using a manual water pressure pump. The water pressure tightness test is
Starting from a water pressure of 0.1 MPa, if there was no water leakage in a stationary state for one minute, the water pressure was increased by 0.1 MPa and the pressure was increased to a maximum of 2.0 MPa, and the presence or absence of water leakage was confirmed. Table 1 shows the results.

(Comparative Example 1)
A metal insert-resin composite molded article was prepared in the same manner as in Example 1 except that an aluminum nut having the surface roughness shown in Table 1 was used, and the airtightness was evaluated. Table 1 shows the results.

[0017]

[Table 1]

In Table 1, the surface roughness and the airtightness were represented by an average value of five samples using five samples (n = 5). As can be seen from Table 1, when the surface of the metal part has an Rz of 2.5 μm or less, preferably 0.5 μm or less, the airtightness is 1.5 MPa or more, preferably 2.0 Mm.
Those having Pa or more were obtained.

[0019]

According to the present invention, the surface of an insert metal part is finished to a predetermined surface roughness Rz or less by an inexpensive physical method, and an insert molded product having high airtightness between a metal insert and a resin can be easily obtained. Can be

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an example of a metal part for insert.

FIG. 2 is a longitudinal sectional view of an example of a metal insert-resin composite molded product.

FIG. 3 is a view showing a test method for waterproofing and airtightness.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 metal insert-resin composite molded product 2 metal part 3 trunk 4 flange 5 resin

Claims (8)

[Claims] 1. A method for molding a metal insert-resin composite molded product in which a metal component is inserted into a resin, wherein the surface of the metal component is mirror-finished in advance, and then the metal component is placed in a mold of an injection molding machine. A method for molding a metal insert-resin composite molded article, comprising: inserting and performing injection molding using a thermoplastic resin. 2. The molding of a metal insert-resin composite molded article according to claim 1, wherein the surface roughness of the metal part after mirror finishing is 2.5 μm or less, expressed as ten-point surface roughness (Rz). Method. 3. The method for molding a metal insert-resin composite molded article according to claim 1, wherein the mirror finishing is a physical method. 4. The method according to claim 3, wherein the physical method uses sandpaper, blue powder or diamond paste. 5. The metal insert according to claim 1, wherein the thermoplastic resin is mainly composed of at least one resin selected from the group consisting of polyacetal, aromatic polyester, polyphenylene sulfide, polyamide, and liquid crystalline polyester. -A method of molding a resin composite molded article. 6. A metal insert-resin composite molded article molded by the method for producing a metal insert-resin composite molded article according to any one of claims 1 to 5. 7. The airtightness between the metal component and the resin is 1.5.
The metal insert-resin composite molded product according to claim 6, which is at least MPa. 8. The metal insert-resin composite molded article according to claim 6, wherein the metal part has a cylindrical portion having a body portion embedded in the resin.