JP2006312747A - Molding material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molding material having excellent moldability, especially injection moldability; providing an obtained molded product, which is light but mechanically strong; having excellent insulation performance, corrosion resistance and nonmagnetization; and capable of manufacturing a molded product which can be repeatedly manufactured with excellent dimensional accuracy, even though the molded product has a complicated and irregular shape. <P>SOLUTION: The molding material contains two kinds of non-hydraulic powder and a resin. The resin is a thermoplastic resin and/or a thermosetting resin, and a percentage of a content of the resin is 40 volume% or less to the total volume. The two kinds of non-hydraulic powder are fly ash having an average particle size of 5-50 μm, and silica fume having an average particle size of a tenth or less of that of the fly ash. A molded product having excellent moldability can be obtained using the molding material. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a molding material, and particularly relates to a molding material that is lightweight and high-strength, excellent in corrosion resistance, not magnetized, and capable of producing a molded body having a complicated shape excellent in dimensional stability.

Currently, for example, screw parts such as bolts, nuts, and washers are used to join and fix various electrical and electronic parts and mechanical parts.
Such screw parts are required to have additional characteristics other than functions related to joining and fixing depending on the characteristics and applications of various parts. For example, heavy electrical parts such as transformers and capacitors are required to have insulating properties, marine parts such as marine instruments and the like are required to have corrosion resistance, and parts such as mobile phones that use electromagnetic waves are required to be non-magnetic.

  Such screw parts are generally made of a metal material such as iron or stainless steel. However, metal screw parts have a large specific gravity, are electrically conductive, and are susceptible to rusting. It has drawbacks such as easy magnetization. Therefore, metal screw parts cannot be used for joining / fixing parts / devices that cause problems due to these characteristics.

On the other hand, plastic screw parts are also used for parts that require weight reduction and insulation.
However, plastic screw parts are easier to stretch than metal screw parts, it is difficult to judge the tightening condition during tightening, and since the bending elastic modulus is small and the amount of deformation for a constant load is large, the tightening torque is at the tip. In addition, since deformation due to creep is large, there is a drawback that long-term dimensional changes such as loosening of the screws are likely to occur.

As a molding material for producing a molded body replacing such a metal part or the like, as described in JP-A-2003-64266, a highly filled resin composition containing a filler and a thermoplastic resin Has been proposed. Molded products obtained using such molding materials can be reduced in weight compared to metal parts, and the mechanical strength can be set higher than that of plastics, but conductive materials are widely used as fillers. Therefore, it has a drawback that it has conductivity and is difficult to use in places where insulation is required. In addition, since the filler of the combination whose size is specified is not used, the moldability is deteriorated, and further, a molded product having a uniform property can be produced, and the mechanical strength such as bending elastic modulus is inferior. .
JP 2003-64266 A

  The object of the present invention is to solve the above-mentioned problems, excellent in moldability, particularly injection moldability, the resulting molded body is lightweight and has high mechanical strength, excellent in insulation, corrosion resistance, non-magnetism, An object of the present invention is to provide a molding material capable of producing a molded body having a reproducible and excellent dimensional accuracy even in a complicated and free shape.

  As a result of repeated researches to achieve the above problems, the inventors of the present invention contain two specific types of non-hydraulic powder and resin, and in particular two types of non-hydraulic that have no electrical conductivity. By using a material containing a powder and a resin, the material containing a non-hydraulic powder having a relationship between two specific average particle sizes, and a resin of a certain amount or less, the moldability, In particular, the present inventors have found that the molded article obtained is excellent in injection moldability, has high strength, is lightweight, and can improve insulation, corrosion resistance, nonmagnetic properties and dimensional stability.

  The molding material of the present invention includes a non-hydraulic powder and a resin, and the resin is a thermoplastic resin and / or a thermosetting resin, and the content thereof is 40% by volume or less with respect to the total capacity. The non-hydraulic powder is a mixed powder composed of fly ash having an average particle diameter of 5 to 50 μm and silica fume having an average particle diameter of 1/10 or less of the fly ash. To do.

Preferably, in the molding material of the present invention, the resin is polyethylene, polypropylene, polystyrene, ABS resin, polyamide, polyacetal, polyester, polycarbonate, modified polyphenylene ether, polysulfone, polyarylate, polyetherimide, polyamideimide, It is selected from the group consisting of polyphenylene sulfide and liquid crystal polyester. More preferably, the molding material of the present invention further comprises a reinforcing material.

  As in the present invention, when a molding material containing fly ash and silica fume, which are two types of non-hydraulic powders having different average particle diameters, is used, the mechanical strength is high while being lightweight. It is possible to provide a molded article with excellent reproducibility and excellent dimensional accuracy even if it is a complex shape and a free shape.

The present invention relates to a specific non-hydraulic powder having a different average particle size, that is, fly ash having an average particle size of 5 to 50 μm, and silica fume and resin having an average particle size of 1/10 or less of the fly ash. It is comprised from the material containing this.
The resin has a total volume content of 40% by volume or less, preferably 35% by volume or less when mixed with the two types of non-hydraulic powders, and a molded product obtained using the material is high. It is desirable for expressing the flexural modulus. If the content of the resin exceeds the specified value, the bending elastic modulus is lowered, which is not preferable.

The non-hydraulic powder includes fly ash, which is a non-hydraulic powder having an average particle diameter of 5 to 50 μm, and other non-water having an average particle diameter of 1/10 or less of the non-hydraulic powder. It is a mixed powder composed of silica fume which is a hard powder.
Thus, by using two types of specific non-hydraulic inorganic powders having greatly different average particle diameters, fluidity necessary for molding of a mixed material with the resin was imparted, and obtained using the material. Since the molded product is filled with inorganic powder with a sufficiently high density, a high flexural modulus can be exhibited.
When a single kind of inorganic powder is used instead of two kinds of specific mixed powders as in the present invention, for example, the resin and the single kind are used so that the resin content is 33% by volume. When the inorganic powder is mixed, the gap between the resin and the inorganic powder cannot be sufficiently filled, making it difficult to obtain a uniform mixed material.

Of the two types of specific non-hydraulic powders having different average particle sizes, the non-hydraulic powder having the larger average particle size is fly ash having an average particle size of 5 to 50 μm, and the average particle size is small. The non-hydraulic powder is silica fume having an average particle size of 1/10 or less than the average particle size of the fly ash.
If the average particle size is composed only of non-hydraulic powder having a particle size of less than 5 μm, the fluidity of the mixed material with the resin may be extremely deteriorated, which is not preferable in terms of molding.
On the other hand, if the non-hydraulic powder having a non-hydraulic powder having an average particle size exceeding 50 μm is included, the non-hydraulic powder tends to be unevenly distributed during molding, and a uniform molded product cannot be obtained.
The mixing ratio of the non-hydraulic powder having two kinds of average particle diameters is not particularly limited, and can be appropriately determined and selected from the fluidity of the mixed material with the resin and the moldability at the time of molding. .

  The resin mixed with the non-hydraulic powder used in the molding material of the present invention is not particularly limited, and a thermoplastic resin and / or a thermosetting resin can be used. It can be used suitably.

The thermoplastic resin that can be used in the present invention means a resin that melts by heating and solidifies when cooled, such as polyethylene, polypropylene, polyvinyl chloride, polystyrene, ABS resin, polyamide, polyacetal, polyester, polycarbonate, modified Polyphenylene ether, polysulfone, polyarylate, polyetherimide, polyamideimide, polyphenylene sulfide, liquid crystal polyester, PEEK, PEN, paraffin wax, montan wax, carnauba wax, fatty acid ester, glycerite, modified wax, silane-modified polyolefin polymer, etc. These thermoplastic resins can be mentioned.
The thermoplastic resin may be used alone or in combination.

  In addition, the thermosetting resin of the above resin means a resin that is solidified by heating as opposed to a thermoplastic resin. For example, phenol resin, urea resin, melamine resin, unsaturated polyester resin, epoxy resin, polyurethane, silicone resin And other known thermosetting resins.

  The mixed material in which the non-hydraulic powder and the resin are mixed can be used for various moldings such as injection molding, extrusion molding, and pressure molding, and can be particularly preferably used for injection molding. .

Preferably, in order to further improve the impact resistance, strength, particularly tensile strength, of the mixed material of the non-hydraulic powder and resin of the present invention, it is desirable to further contain a reinforcing material in the mixed material.
Examples of the reinforcing material include fibers such as glass fiber, carbon fiber, and aramid fiber, and reinforcing fibers such as potassium titanate whisker.
The length of the reinforcing fiber is preferably 1 to 20 mm, more preferably 3 to 13 mm, and the thickness is preferably 5 to 30 μm. This facilitates preparation of the mixed material and molding of the resulting mixed material. From the viewpoint of sex.

  About the addition amount of the said reinforcing material, it is preferable to add 1-100 volume parts with respect to 100 volume parts of said resin, and it is more preferable to add 3-50 volume parts especially. This is because when the amount is more than 100 parts by volume, the influence on the fluidity is large and causes molding failure. When the amount is less than 1 part by volume, the effect of the reinforcing material is not exhibited.

  In order to prepare the molding material of the present invention, the resin, fly ash and silica fume that are the non-hydraulic powders, and a reinforcing material that is further added as necessary are uniformly mixed at the above-described ratio. To mix. The mixing method is not particularly limited as long as these components can be mixed uniformly. Fly ash and silica fume can be mixed in advance to form a mixed powder, or these materials can be mixed simultaneously. is there.

Next, using the obtained molding material, a molded body is manufactured by molding into a predetermined shape.
Specifically, an injection molding method, an extrusion molding method, a pressure molding method, or the like can be used as the molding method, but the molding method is not limited to these, and a known molding method can be used.
In particular, in injection molding, a three-dimensional arbitrary shape can be molded with high accuracy, so that a good molded body with excellent dimensional accuracy, such as a screw part, can be manufactured.
By using injection molding, for example, screw parts with complicated shapes and free shapes, such as nuts pre-threaded, bolts bent in an L shape, and bolts with cavities in the middle, with good reproducibility and dimensions It can be manufactured with high accuracy.

  In the case of using injection molding, it is preferable to mix the resin and the two types of non-hydraulic powders and form them into pellets, for example, and use them as raw materials for injection molding.

In particular, when a thermoplastic resin is used as the resin, the mixed material of the two types of non-hydraulic powder and the resin is melt-kneaded at a temperature equal to or higher than the softening point of the thermoplastic resin, and the pelletized raw material for injection To form.
The pellet-like raw material is melted and kneaded again in a heating cylinder inside the injection molding machine, and filled into a mold having a desired shape by an injection device, whereby a molded body can be obtained.

  Thus, the molded product obtained using the molding material of the present invention is lightweight and has high mechanical strength, and in particular, has insulation, corrosion resistance, non-magnetic properties and long-term dimensional stability. It can have excellent properties.

The present invention will be described in detail based on the following examples, comparative examples, and test examples, and a screw part will be described as an example of a molded body using a molding material.
<Examples 1-2>
<Example 1>
According to the blending ratio (volume part) shown in Table 1, fly ash (average particle size 20 μm, spherical particles, trade name: Chubu Fly Ash, manufactured by Chubu Techno Co., Ltd.) and silica fume (average particle size: 0.2 μm, trade name: microsilica , Manufactured by SKW Co., Ltd.), using polyphenylene sulfide resin (trade name: Fortron, manufactured by Polyplastics Co., Ltd.) as a resin, and further adding carbon fiber (trade name: Besfight, manufactured by Toho Tenax Co., Ltd.) as a reinforcing material, The molding material was prepared by mixing uniformly.

Next, the molding material was kneaded at 270 ° C. for 45 minutes with a kneader kneader (trade name; Labo Blast Mill: manufactured by Toyo Seiki Seisakusho Co., Ltd.) to obtain pellets.
The pellets were injection molded into a bolt shape with M (metric screw) 1.4 and length 10 mm to obtain a bolt molded body.

<Example 2>
A bolt molded body was obtained in the same manner as in Example 1 except that carbon fiber as a reinforcing material was not used.

<Comparative Examples 1-2>
As Comparative Example 1, an M1.4 bolt having a length of 10 mm made of polycarbonate (trade name Toughlon, manufactured by Idemitsu Petrochemical Co., Ltd.) was produced. Moreover, as Comparative Example 2, a SUS410 stainless bolt (manufactured by Tsubame Seiren Seisakusho Co., Ltd.) processed by a rolling method was used.

<Test example>
The bolt molded bodies obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were subjected to the following tests.
[Evaluation of specific gravity]
Specific gravity measured the specific gravity of each test body based on ASTM D-792.

[Evaluation of breaking torque and tightening angle to break]
The bolt 1 of each test specimen was covered with a cemented carbide spacer (inner diameter φ1.5 × 8) 3, and a brass nut (with Ni plating) 4 was screwed into the bolt 1. As shown in FIG. 1, the screw head of the bolt 1 was fixed to the vice 2, and the nut 4 was tightened until it was broken with a torque driver, and the maximum value was measured as the breaking torque.
The tightening angle was measured by reading the rotation angle of the torque driver in units of 15 ° while observing the scale of the angle on the vise.

[Evaluation of tensile elongation]
The tensile elongation was measured in accordance with ASTM D-638 and the tensile elongation rate of each specimen was measured.

[Evaluation of flexural modulus and bending creep strain]
The bending elastic modulus and bending creep strain were measured in accordance with ASTM D-790 (19.6 MPa, 23 ° C., 1000 hours), and the bending elastic modulus and bending creep strain of each specimen were measured.

[Evaluation of volume resistivity]
The volume resistivity was measured in accordance with ASTM D-257 and the volume resistivity of each specimen was measured.

[Evaluation of corrosion resistance]
Corrosion resistance was judged by visually observing the presence or absence of rust on each specimen in accordance with JIS Z 2371.

[Evaluation of magnetism]
The magnetism is determined by visually observing whether or not the specimen is held by the magnet using a commercially available bar magnet (width about 1 cm x height about 0.5 cm x length about 10 cm). It was judged.
These results are shown in Table 1.

From the above results, the bolt molded body obtained using the molding material of the present invention has a specific gravity of about one-fourth that of the metal screw part of Comparative Example 2, and is lighter. It is understood.
The breaking torque is about 40% higher than that of the resin screw part of Comparative Example 1.
Furthermore, regarding the tightening angle leading to the breakage, the resin screw part rotates 2-5 times and breaks, but the bolt molded body using the molding material of the present invention does not extend and appear to be deformed. It broke at a clamping angle of about 30 °.

Further, it is understood that the tensile elongation, the flexural modulus, and the bending creep strain all show favorable characteristics as compared with the resin screw part of Comparative Example 1.
Further, the volume resistivity is slightly higher in conductivity than the resin screw part of Comparative Example 1, but the conductivity is sufficiently suppressed as compared with the metal screw part of Comparative Example 2. I understand that.

  As for corrosion resistance and non-magnetism, comparable results were obtained as compared with the metal screw part of Comparative Example 2. However, such a result was obtained because the material of the metal screw part of Comparative Example 2 was stainless steel, and when the material is iron like the screw part currently widely used. The bolt molded body using the molding material of the present invention exhibits superior characteristics regarding corrosion resistance and non-magnetism.

  The molding material of the present invention can be applied to obtain a molded body in a field where lightness, mechanical strength, insulation, corrosion resistance, non-magnetism, and the like are required, such as a screw.

It is a figure which shows the measuring methods, such as a rupture torque of the volt | bolt which is a screw component as a molded object.

Explanation of symbols

1 Specimen 2 Vise 3 Spacer 4 Nut

Claims (3)

  A non-hydraulic powder and a resin, and the resin is a thermoplastic resin and / or a thermosetting resin, the content of which is 40% by volume or less based on the total volume. A molding material, which is a mixed powder comprising fly ash having an average particle diameter of 5 to 50 µm and silica fume having an average particle diameter of 1/10 or less of the fly ash.   The molding material according to claim 1, wherein the resin is polyethylene, polypropylene, polystyrene, ABS resin, polyamide, polyacetal, polyester, polycarbonate, modified polyphenylene ether, polysulfone, polyarylate, polyetherimide, polyamideimide, polyphenylene sulfide, and the like. A molding material selected from the group consisting of liquid crystalline polyesters. The molding material according to claim 1, further comprising a reinforcing material.

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