JP2007016221A - Resin material for molding and molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin material for molding excellently reducing molding shrinkage and affording a molded product having excellent thin-wall moldability, high dimensional accuracy according to design and excellent stability for thermal deformation and to provide the molded product using the material. <P>SOLUTION: The resin material for molding comprises a thermoplastic resin, one kind of fly ash and silica fume. The average particle diameter of the silica fume is ≤1/10 of the average particle diameter of the one kind of fly ash and the compounding ratio of the one kind of fly ash/silica fume is (20/80) to (80/20) expressed in terms of mass ratio. The thermoplastic resin is contained in an amount of 10-40 vol.% in the resin material for molding. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a molding resin material and a molded article, and particularly relates to a molding resin material and a molded article that can be suitably used for injection molding and can provide a molded article having excellent dimensional accuracy.

In recent years, molded products of various types of shapes have been required, and conventionally used metals are usually made of resin to be molded into a desired shape by processing such as cutting. Compared to a molded product, the number of steps required to obtain a molded product is large, and the lack of mass productivity is a drawback. For this reason, many metal parts are made of resin.
However, molded products using resin are excellent in mass production, but deformation of the molded product occurs due to shrinkage that occurs while the molten resin solidifies, and it is possible to obtain molded products with dimensions different from those at the time of design. Therefore, it is difficult to design to obtain a desired molded product.

  Therefore, in molded products using resin, in response to such problems, investigations have been made on filler-containing resin compositions in which inorganic fillers and reinforcing fibers are filled into the resin. There is a tendency to increase the density, and there is a demand for high dimensional accuracy that cannot be realized with a molded product obtained from a resin material filled with a conventional filler or reinforcing fiber as a molding resin material and a molded product.

In response to such a request, Japanese Patent Application Laid-Open No. 2005-82661 (Patent Document 1) describes excellent fluidity at the time of molding even when an inorganic filler is contained at a high concentration, and against a temperature change of −30 ° C. to 100 ° C. For the purpose of providing a resin material that gives excellent dimensional accuracy and anisotropy, 40 to 400 fillers comprising fly ash, fibrous filler and / or scaly inorganic filler with respect to 100 parts by weight of polyphenylene sulfide resin. A resin material for optical device mechanism parts has been proposed, which contains 5 parts by weight and contains fly ash in an amount of 5 to 95% by weight in all filler components.
However, the fibrous and / or flaky inorganic filler has a significant decrease in fluidity of the resin filled with the spherical filler, and the combination of the fibrous and / or flaky inorganic filler and fly ash The function of filling the filler gap is low, and the amount of resin used in the examples is more than half in terms of volume, and it is not expected to obtain a molded product with high dimensional accuracy. .

  JP 2003-64266 A (Patent Document 2) aims to provide a highly-filled resin material that increases the degree of freedom of the shape of a molded product, can be melt-processed, and can efficiently exhibit the characteristics of the filler used. As described above, a highly-filled resin material is proposed that is composed of 1 to 40% by volume of a thermoplastic resin and 99 to 60% by volume of a filler. There is no technical idea for filling the gap with other fillers of fine particles of submicron order, and therefore satisfactory high filler filling cannot be obtained.

JP-A-2000-336254 (Patent Document 3) and JP-A-2003-82215 (Patent Document 4) disclose a molded product using fly ash as an inorganic filler. Specifically, The former includes a polyester resin material composed of 30 to 99 parts by weight of a thermoplastic polyester resin and 70 to 1 part by weight of fly ash, wherein the fly ash has a specific surface area of 1000 to 8000 cm ² / g, The latter discloses a kneaded molding material comprising fly ash, an unsaturated polyester resin, and a small amount of a silane coupling agent.

However, since the material using fly ash as the filler is a spherical filler, the fluidity is gradually lowered even when the filler is filled, and the purpose can be to increase the filling rate. Since only one type of fly ash is filled as the filler, the particle size of the filler is not so wide and cannot be increased as much as expected.
Specifically, in the above-described embodiment, the amount of resin exceeds half in terms of volume, and therefore, the molding shrinkage of the obtained molded product is not particularly small, and has a high dimensional accuracy as desired. It is difficult to obtain a molded product.

As described above, it is extremely important for a molded product obtained by molding a resin material, especially a thermoplastic resin compound, to have the dimensions as designed in order to satisfy the required strict accuracy, but it is still satisfactory. However, the present situation is that no molding resin material capable of obtaining high dimensional accuracy is obtained.
JP 2005-28761 A JP 2003-64266 A JP 2000-336254 A JP 2003-82215 A

The object of the present invention is to solve the above-mentioned problems, reduce the molding shrinkage ratio, have excellent thin-wall moldability, have high dimensional accuracy as designed, and have excellent stability against thermal deformation. It is providing the resin material for shaping | molding which can obtain, and the molded article using the said material.
Another object of the present invention is to provide a molding resin material and a molding resin material that can be obtained in a dimensional stability, that is, in a shape as designed, with a gradual decrease in fluidity and with a small and complex shape. It is to provide a molded article using the material.
Furthermore, another object of the present invention is to provide a molding resin material and a molded article suitably used for injection molding, in addition to the above-mentioned object.

  The present inventors have used these inorganic fillers existing inside the resin by using a combination of fly ash type I and silica fume having different sizes when molding a resin material, particularly injection molding a thermoplastic resin. The other silica fume particles were filled with nectar in the gaps between the fly ash type I particles, and they found that they mutually exhibited a ball bearing effect in the molten resin, leading to the present invention. Is.

The molding resin material of the present invention includes a thermoplastic resin, fly ash type I and silica fume, and the average particle size of the silica fume is 1/10 or less of the average particle size of fly ash type I, The fly ash type I / silica fume is blended in a mass ratio of 20/80 to 80/20, preferably the fly ash type I has a particle size of 0.5 to 80 μm, The silica fume preferably has a particle size of 0.01 to 0.5 μm.
More preferably, a fibrous reinforcing material is included.

  In the molding resin material of the present invention, it is further desirable that the thermoplastic resin is contained in an amount of 10 to 40% by volume, and the fly ash type I and silica fume which are the two kinds of inorganic fillers contained are necessary. It is particularly preferred that the total capacity with the fibrous reinforcing material contained depending on is 99 to 60% by volume.

  The molded product of the present invention is formed by using the molding resin material of each of the present inventions, and is preferably obtained by injection molding of the molding resin material.

The molding resin material of the present invention can be filled with a large amount of these inorganic fillers by combining fly ash type I, which is a specific inorganic filler, and silica fume, and the molding material of the present invention is used. The molded product has a small molding shrinkage (for example, flow direction / orthogonal direction = 0.2 / 0.3) and a small difference between the flow direction / orthogonal direction, so that high dimensional accuracy can be realized, Both the uneven and thick molded product and the thin molded product have an excellent effect of having dimensional accuracy as designed.
Further, when the molding resin material of the present invention is used for injection molding, fly ash type I and silica fume exhibit a ball bearing effect in the molten resin, thereby increasing the rolling property and improving the fluidity. It is possible to improve and accurately manufacture a molded product having a complicated shape.

Furthermore, in addition to the above-mentioned effects, the molding resin material of the present invention can effectively obtain the performance of these highly filled inorganic fillers by combining fly ash type I and silica fume. Has the following preferable effects.
1) Thermal conductivity is increased and heat dissipation is improved.
2) Heat resistance is improved.
3) The coefficient of linear expansion is lowered, the coefficient of thermal expansion is as low as that of fine ceramics, and the dimensional change due to heat is small.
4) Higher elastic modulus and vibration damping than engineering plastics are obtained.

The present invention is illustrated by the following preferred examples, but is not limited thereto.
The molding resin material of the present invention includes a thermoplastic resin, fly ash type I and silica fume, and the average particle size of the silica fume is 1/10 or less of the average particle size of fly ash type I, The mixing ratio of fly ash type I / silica fume is 20/80 to 80/20 by mass ratio, preferably the particle size of the fly ash type I is 0.5 to 80 μm, the particle size of the silica fume Is preferably 0.01 to 0.5 μm, and more preferably, these fly ash type I and silica fume are spherical.
In this way, by combining fly ash type I and silica fume having different particle diameters, silica fume having a small particle diameter enters the gaps of fly ash type I having a large particle diameter, resulting in a multiple particle size structure. In addition to exhibiting the maximum ball bearing effect, it is possible to impart inorganic properties added to a resin such as a thermoplastic resin as much as possible, and excellent dimensional stability can be obtained.

The thermoplastic resin used in the present invention means, for example, a resin that can be plasticized to the extent that it can be molded by heating, and the type thereof is not particularly limited. For example, polyethylene terephthalate, polybutylene terephthalate, polycyclohexylene dimethylene terephthalate, Polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate / terephthalate, polybutylene isophthalate / terephthalate, polycyclohexylene dimethylene isophthalate / terephthalate, poly (p-hydroxybenzoic acid / ethylene terephthalate), non-liquid crystalline semi-aromatic Polyester, polyester such as non-liquid crystalline wholly aromatic polyester, polycarbonate, aliphatic polyamide, aliphatic-aromatic polyamide, polyamide such as wholly aromatic polyamide, Reoxymethylene, polyimide, polybenzimidazole, polyketone, polyether ether ketone, polyether ketone, polyether sulfone, polyphenylene oxide, phenoxy resin, polyphenylene sulfide, liquid crystal polymer, olefin polymer such as polypropylene, polyethylene, polystyrene, ethylene / Propylene copolymer, ethylene / 1-butene copolymer, ethylene / propylene / non-conjugated diene copolymer, ethylene / ethyl acrylate copolymer, ethylene / glycidyl methacrylate copolymer, ethylene / vinyl acetate / methacryl Acid glycidyl copolymer, ethylene / propylene-g-maleic anhydride copolymer, olefin copolymer such as ABS, polyester polyether elastomer, polyester polyester Selected from elastomers such ether elastomers, mixtures of any known one or more thermoplastic resins.
In particular, polyphenylene sulfide, polyamide, polycarbonate, polypropylene, polyurethane, a mixture of one or more liquid crystal polymers, and the like can be suitably used from the viewpoint of fluidity and filling properties.

In the present invention, fly ash type I and silica fume are used in combination.
Here, fly ash includes fly ash types I to IV according to the JIS A 6201 standard. In the present invention, the fly ash type I of the JIS standard is used.
Thus, even fly ash is not fly ash type II-IV, etc., but by using a combination of fly ash type I and silica fume, compared to the case of using other fly ash types II-IV, etc. Thus, the fluidity of the obtained material is increased, the molding shrinkage rate is reduced, and the molding of a thin wall is possible, so that the effects of the present invention can be achieved very well.
In the present invention, fly ash type I has a high proportion of spherical particles, so the ball bearing effect is extremely high. Furthermore, since there is the least amount of unburned carbon, the amount of oil absorption is the smallest and the fluidity is reduced even at high filling. Has the function of being small.

In particular, the average particle size of the fly ash type I and silica fume is such that the average particle size of silica fume is 1/10 or less of the average particle size of fly ash type I, preferably 1/20 or less, more preferably It is preferable that the ratio is at least 1/40 in order to improve the dimensional stability by densely filling these two specific types of fly ash type I and silica fume.
The average particle diameter is obtained by taking a photograph using a scanning electron microscope, measuring the major axis and minor axis of each particle, calculating the average major axis and the average minor axis, respectively, and calculating the average major axis and the minor minor axis. It is obtained by averaging.
By combining and mixing fly ash type I and silica fume having different particle diameters in this way, a multiple particle size constitution filler is obtained, and by forming a multiple particle size constitution in which silica fume particles of the particle size enter between the fly ash type I. In addition, a large amount of inorganic filler can be densely filled in the resin material, and thereby, an effective ball bearing effect can be exhibited in the molten resin, thus improving the dimensional accuracy of the molded product. It can be done.

In addition, the silica fume having a small particle diameter is not only filled with primary particles in the resin material, but also aggregates the primary particles to form secondary to quaternary aggregate particles having an appropriate size. It is also possible to fill the gaps between relatively large grains and exert a ball bearing effect.
Furthermore, the fly ash type I or silica fume preferably has a surface with a slight unevenness in order to increase the rolling property in the molten resin during injection molding.
The fly ash type I has a particle size of 0.5 to 80 μm, preferably 0.5 to 50 μm, and the silica fume preferably has a particle size of 0.01 to 0.5 μm. Can be suitably used 0.05-0.5 μm, especially by using a combination of fly ash type I and silica fume having such a particle size range, the resin material can be closely packed, A more effective ball bearing effect can be exhibited and dimensional accuracy can be improved.
The particle size is a value measured by a scanning electron microscope as described above.

In particular, these fly ash type I and silica fume are preferably those having a spherical shape, and the ball bearing effect can be maximized.
Here, “spherical” not only means a perfect spherical sphere, but also a slightly elliptical shape, a gourd shape, etc., and a spherical shape such as a granular shape in which the surface of these shapes has subtle irregularities to some extent. It is intended to include those having a three-dimensional shape that approximates to, and excludes those having a two-dimensional shape such as a fiber shape, a plate shape, and a scale shape, and a true sphere is preferable.
That is, the granular shape has a shape that is relatively close to a true sphere. For example, those having an average major axis / average minor axis of 1 or more and less than 3 are preferable.
As described above, by removing fillers having a two-dimensional shape such as fibrous, plate-like, and scale-like, the fluidity is gradually lowered even when the inorganic filler is filled in the resin material, and the good fluidity is obtained. Can be secured.

  The blending ratio of fly ash type I and silica fume is 20/80 to 80/20, preferably 35/65 to 65/35 in terms of mass ratio. This is because it may be difficult to obtain a molded product.

Furthermore, in order to further increase the strength of the obtained molded product, it is possible to contain a fibrous reinforcing material as necessary.
As the fibrous reinforcement, there can be used fibers such as short fibers, whiskers, and fibrids having heat resistance and excellent mechanical properties such as elastic modulus, strength, and elastic recovery rate, such as glass fibers and carbon fibers. , Alumina fibers, silicon carbide fibers, whiskers such as potassium titanate and aluminum borate, metal fibers such as boron fibers and titanium fibers, and organic fibers such as aramid fibers, with glass fibers being particularly preferred.

As for the diameter and length of the fibrous reinforcing material, if the fiber length is too long, it is difficult to uniformly mix and disperse with the thermoplastic resin, fly ash type I and silica fume, and conversely if it is too short, the effect as a reinforcing material is obtained. In general, a fiber having a fiber length of 0.1 to 10 mm and a diameter of 9 to 15 μm can be preferably used.
When the fiber length is less than 0.1 mm, it is difficult to obtain a molded product having excellent mechanical strength such as bending strength.
On the other hand, when the fiber length exceeds 10 mm, when formed into a molded product, the fibrous reinforcing material is raised on the surface and the appearance is inferior.

  The blending ratio of the fibrous reinforcing material is not particularly limited, but it is preferably 5 to 40% by volume in the molding resin material. This is less than 5% by volume, and the effect of improving the strength is not so much. If it exceeds the upper limit, the fluidity is deteriorated, and defects such as “nest” may occur in the obtained molded product, which is not preferable.

The blending ratio of the thermoplastic resin and the fly ash type I, silica fume and the fibrous reinforcing material blended as necessary is 10 to 40% by volume, more preferably 20 to 40% by volume of the thermoplastic resin. It is a volume%, More preferably, it is 30-40 volume%, and the remainder is the following additive added as needed with the said fly ash I seed | species, a silica fume, and a fibrous reinforcement.
When the content of the thermoplastic resin exceeds 40% by volume, the molding shrinkage rate of the obtained molded product increases, and it may be difficult to ensure dimensional accuracy, which is not desirable.
Further, if the content of the thermoplastic resin is less than 10% by volume, it may be difficult to ensure the fluidity necessary for molding, which is not preferable.

  In the molding resin material of the present invention, in addition to the reinforcing material described above, if necessary, a heat stabilizer, a light stabilizer, an antioxidant, a plasticizer, a lubricant, a colorant, a foaming agent, a release agent, Additives such as impact resistance improvers may be blended.

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

Specifically, a thermoplastic resin, fly ash type I, silica fume, etc. are mixed using a Banbury mixer, kneader, roll, and then manufactured by using a hot melt kneader such as a single screw or twin screw extruder. In particular, it is preferable to use a twin-screw extruder suitably from the viewpoint of the uniformity of the filler-filled resin material obtained.
In addition, the thermoplastic resin to be blended is particularly preferably used in terms of handling because of the composition uniformity, kneadability, etc. of the obtained composition, using the same reduced size or powder as in the fly ash type I and silica fume used. In addition, pellets or powders may be used. When the amount of fly ash type I or silica fume is large, it is preferable from the viewpoint of production efficiency to use a small diameter or powder.

In the case of using injection molding, it is preferable to mix the resin, the fly ash type I and silica fume, and form, for example, pellets, which are used as raw materials for injection molding. At a temperature equal to or higher than the softening point, a mixed material of the fly ash type I, silica fume, resin, and the like is melt-kneaded to obtain a pellet raw material for injection.
The pellet-like raw material is melted and kneaded again in a heating cylinder inside the injection molding machine, and filled in a mold having a desired shape by an injection device to obtain a molded product.

The molding resin material of the present invention can be formed into a desired molded product by a normal molding method.
For example, known molding methods such as injection molding, extrusion molding, press molding and injection molding can be used.
In particular, in injection molding, it is possible to accurately form a three-dimensional arbitrary shape, and to manufacture a thin molded product having a complicated shape or a free shape with high reproducibility and dimensional accuracy.

  As described above, when the molding resin material of the present invention is used, it is possible to manufacture a molded product having excellent fluidity and a complicated shape with a thickness of uneven thickness and a thin molded product with high dimensional accuracy.

The invention is illustrated by the following examples, comparative examples and test examples.
Material : Poniphenylene sulfide A; Fortron A0220 Polyplastics Co., Ltd. (thermoplastic resin, specific gravity 1.3)
-Poniphenylene sulfide B; Fortron 6165A4 manufactured by Polyplastics Co., Ltd. (thermoplastic resin, specific gravity 1.96)
・ Fly ash type I; final ash Yoden Sangyo Co., Ltd. (specific gravity 2.3, average particle size 5.5 μm, particle size 0.5-30 μm)
・ Fly ash type II: Chubu fly ash Techno Chubu Co., Ltd. (specific gravity 2.3, average particle size 10 μm, particle size 1 to 50 μm)
・ Fly ash type III; Chubu fly ash made by Techno Chubu Co., Ltd. (specific gravity 2.3, average particle size 10 μm, particle size 1 to 50 μm)
・ Fly ash type IV; Ecoashu Yoden Sangyo Co., Ltd. (specific gravity 2.3, average particle size 40 μm, particle size 5 to 100 μm)
・ Silica fume; Microsilica Elchem Co., Ltd. (specific gravity 2.3, average particle size 0.2 μm, particle size 0.05 to 0.5 μm)
・ Glass fiber: CS 3J-256 Nitto Boseki Co., Ltd. (specific gravity 2.9)

Examples 1-3; Comparative Examples 1-8
Using a blending ratio shown in Table 1, each raw material was mixed with a blender, and a cylinder temperature was set to 300 ° C., using a 35 mmφ twin-screw extruder (manufactured by Ikekai Tekko, PCM30), a set temperature of 300 ° C. and a rotation speed of 200 rpm. The mixture was uniformly melted and kneaded in order to obtain pellets.
Each pellet obtained was tested with an injection molding machine (manufactured by Sumitomo Heavy Industries: Promat 100A) 90 mm long × 90 mm wide × 3 mm high test piece (side gate, gate size: width 5 mm × height 1 mm) A molded product and a test piece (side gate, gate size: width 5 mm × height 1 mm) of 90 mm × width 90 mm × height 1 mm were obtained.

The following tests were conducted on the molded products obtained in Examples 1 to 3 and Comparative Examples 1 to 8.
Fluidity Test Using “Flow Tester, CFT-500D” manufactured by Shimadzu Corporation, the material viscosity was measured when passing through an orifice having a diameter of 1 mm and a length of 10 mm at a temperature of 300 ° C., a load of 50 kgf as measurement conditions.
And moldability <br/> moldability (1) above, the vertical 90 mm × horizontal 90 mm × height test pieces (side gate, the gate size: Width 5 mm × height 1mm) of 3mm when the molded article, sufficient The mold filled in the mold was evaluated as moldable, and the mold not sufficiently filled was evaluated as unmoldable.
Formability (2) When molding the above-mentioned test pieces (side gate, gate size: width 5 mm x height 1 mm) of 90 mm long x 90 mm wide x 1 mm high, the mold is fully filled Those that could be molded were evaluated and those that were not sufficiently filled were evaluated as not moldable.

Dimensional accuracy Each test piece (length 90mm x width 90mm x height 3mm) was measured with a digital caliper (Mitutoyo) and compared with the mold dimensions measured in the same way. Then, the mold shrinkage was calculated.
As shown in FIG. 1, the distance between the gate surface and the anti-gate surface is the flow direction length, and the distance between the side surfaces is the perpendicular direction length.
In addition, each of the obtained test pieces (90 mm × width 90 mm × height 1 mm) was similarly measured as shown in FIG. 2, and the molding shrinkage was measured as shown in FIG. A result almost equal to the molding shrinkage rate of each of the test pieces (length 90 mm × width 90 mm × height 3 mm) was obtained.

  These results are shown in Table 1 below.

  Since the molded products of Examples 1 to 3 use fly ash type I and silica fume having different average particle diameters, they have excellent fluidity, small molding shrinkage ratio, excellent thin-wall molding, and extremely good dimensional accuracy. It became clear that.

  The molding resin material of the present invention can be used as a substitute material for various molded products that use conventional thermoplastic resins, ceramics, engineering plastics and metals, as building materials, electronic / electric equipment, precision machinery equipment, office equipment. It can be applied to various applications such as automobile / vehicle-related parts, communication equipment, and thermal equipment parts.

The perspective view of the molded article (90 mm x 90 mm in width x 3 mm in height) obtained using the resin material for shaping | molding. The perspective view of the molded article (90 mm x 90 mm in width x 1 mm in height) obtained using the resin material for shaping | molding.

Claims (6)

  It contains a thermoplastic resin, fly ash type I and silica fume, and the average particle size of the silica fume is 1/10 or less of the average particle size of fly ash type I, and the blending ratio of the fly ash type I / silica fume Is a resin material for molding, wherein the mass ratio is 20/80 to 80/20.   The molding resin material according to claim 1, wherein the fly ash type I has a particle size of 0.5 to 80 μm, and the silica fume has a particle size of 0.01 to 0.5 μm. Resin material.   The molding resin material according to claim 1 or 2, further comprising a fibrous reinforcing material.   The molding resin material according to claim 1, wherein the molding resin material contains 10 to 40% by volume of the thermoplastic resin.   A molded article comprising the molding resin material according to claim 1. 6. The molded product according to claim 5, wherein the molded product is obtained by injection molding the molding resin material.

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