JP2018065987A - Inorganic filler-containing resin composition, inorganic filler-containing resin composition molding, and method for producing inorganic filler-containing resin composition molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inorganic filler-containing resin composition that achieves both strength and designability.SOLUTION: A resin composition containing an inorganic filler, contains at least a thermoplastic resin, an inorganic filler, and a pigment. When the resin composition is molded into a test piece of 50 mm in length, 10 mm in width, and 1 mm in thickness, its molding has a light transmittance of 8% or less at a wavelength of 700 nm in the thickness direction, and also has a brightness L* of 50-90.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an inorganic filler-containing resin composition to which a design property is imparted, for example, used for an electronic device casing, and a molded body molded thereby.

  In order to provide design and assembly workability while ensuring impact resistance and rigidity in a small electronic device casing, a molded body made of a resin composition containing an inorganic filler is partially formed on a casing made of metal or the like. (Patent Document 1). Moreover, in order to match | combine a color tone with a metal component etc. from such a viewpoint of design property, coloring agents, such as a pigment, may be added to such an inorganic filler containing resin composition. And the part in which this molded object was provided is often cut after shaping | molding, in order to arrange the shape as a housing | casing.

  Inorganic filler-containing resin compositions contain an inorganic filler in order to maintain the strength of the housing, but many inorganic fillers in the form of needles and fibers are used to maintain the strength. Therefore, depending on the molded body, the inorganic filler present on the surface portion of the molded body is oriented vertically, and the cutting surface of the inorganic filler is exposed to the surface by cutting in that state, which is not intended. A design was produced, resulting in a defective appearance, and the productivity of the molded product was impaired.

WO2011 / 155289

  This invention is made | formed in order to solve the above subject, The objective is to provide the inorganic filler containing resin composition for making intensity | strength and designability compatible. Furthermore, it is providing the manufacturing method of the molded object by the said resin composition, and the molded object.

The present inventors have found that the object of the present invention can be achieved by the following.
(1) A resin composition containing an inorganic filler, which contains at least a thermoplastic resin, an inorganic filler, and a pigment, and is a test having a length of 50 mm, a width of 10 mm, and a thickness of 1 mm by the resin composition. An inorganic filler-containing resin composition having a light transmittance of 8% or less at a wavelength of 700 nm in the thickness direction of the molded product and a lightness L * of 50 to 90 when the molded product is molded.

  (2) The inorganic filler-containing resin composition according to (1), wherein the pigment is a zinc sulfide pigment.

  (3) The inorganic filler-containing resin composition according to (1) or (2), wherein the inorganic filler is glass fiber.

  (4) A molded body obtained by molding the inorganic filler-containing resin composition according to any one of (1) to (3), wherein a part of the inorganic filler is exposed on the surface of the molded body. An inorganic filler-containing resin composition molded article.

  (5) An inorganic filler-containing resin composition molded body in which a part of the inorganic filler exposed on the surface of the molded body is a cross-section of the solid filler.

  (6) A method for producing an inorganic filler-containing resin composition molded article according to (4) and (5), wherein the inorganic filler-containing resin composition is injection-molded to obtain an injection-molded article, and the injection The manufacturing method of the inorganic filler containing resin composition molded object which has the process of cutting a molded object.

  ADVANTAGE OF THE INVENTION According to this invention, the inorganic filler containing resin composition which made intensity | strength and designability compatible can be provided.

It is the schematic of a test piece molded object. It is the schematic of a strip-shaped test piece.

Hereinafter, specific embodiments of the present invention will be described in detail.
<< 1. Inorganic filler-containing resin composition >>
The inorganic filler-containing resin composition of the present invention includes at least an inorganic filler, a thermoplastic resin, and a pigment. The inorganic filler-containing composition has a length as shown in FIG. When a molded specimen having a thickness of 50 mm, a width of 10 mm, and a thickness of 1 mm is molded, the light transmittance at a wavelength of 700 nm in the thickness direction of the molded body is 8% or less, and the lightness L * is 50 to 90. It is characterized by that.

  In the inorganic filler-containing resin composition of the present invention, by adjusting the light transmittance and color (brightness) of a specific test piece molded body molded using the resin composition to be within a specific range. The occurrence of poor appearance due to the inorganic filler when cut can be reduced. In other words, regardless of injection molding conditions, cutting processing conditions, etc., it is possible to suppress the occurrence of unintended designs such as whitening of a part of the surface of the molded body, and consequently reduce the occurrence of defective appearance. it can.

[Light transmittance of molded product]
In the inorganic filler-containing resin composition of the present invention, as described above, when the resin composition is molded into a specific test piece molded body (FIG. 1) having a length of 50 mm, a width of 10 mm, and a thickness of 1 mm, The light transmittance at a wavelength of 700 nm in the thickness direction is 8% or less. Thus, the transmittance | permeability in wavelength 700nm is 10% or less, The effect which reduces the external appearance defect by an inorganic filler when cut is exhibited. Further, the light transmittance is more preferably 5% or less, and further preferably 3% or less.

[Lightness of molded product]
Moreover, in the inorganic filler containing resin composition of this invention, the lightness L * of the test piece molded object mentioned above is 50-90. When the value of L * is in such a range, the design of the molded body is easily exhibited, and the effect of reducing the appearance defect of the present invention when cut is remarkable. Further, the lightness L * is more preferably in the range of 60-80.

  The light transmittance and the lightness L * of the molded body of the inorganic filler-containing resin composition of the present invention are adjusted based on the inorganic filler, pigment type, and content contained in the resin composition. Below, the component which comprises an inorganic filler containing resin composition is demonstrated.

[Thermoplastic resin]
It does not specifically limit as a thermoplastic resin, All the thermoplastic resins which can be normally used can be selected suitably.

  For example, polyphenylene sulfide, polypropylene, polyethylene, polyethylene terephthalate, polyamide, polycarbonate, polystyrene, acrylonitrile-styrene copolymer, acrylonitrile-styrene-butadiene copolymer, ethylene-vinyl acetate copolymer, polyoxymethylene, polybutylene terephthalate, Examples thereof include polyether ether ketone, aromatic polyester or aromatic polyester amide-based liquid crystalline polymer. Among these, polybutylene terephthalate, polyphenylene sulfide, and liquid crystalline polymer are preferable from the viewpoint of impact resistance and rigidity.

  Further, the content of the thermoplastic resin in the inorganic filler-containing resin composition is not particularly limited, but is preferably 30 to 90% by mass, and is 40 to 80% by mass in terms of impact resistance, rigidity and moldability. % Is more preferable, and 50 to 70% by mass is even more preferable.

[Inorganic filler]
As the inorganic filler, any of fibrous fillers and non-fibrous fillers (powder and filler, etc.) may be used, or two or more kinds may be used in combination. Thus, according to the resin composition containing an inorganic filler, the impact resistance and rigidity of the molded product can be improved.

  Among the various inorganic fillers described above, it is preferable to use a fibrous filler from the viewpoint of imparting more excellent impact resistance and rigidity. Among the fibrous fillers, glass fibers are particularly preferable. As the glass fiber, any known one is preferably used, such as a glass fiber diameter, a shape such as a cylinder, a saddle-shaped cross-section, an oval cross-section, or a length used when manufacturing chopped strands or rovings, a glass cutting method, etc. Is not particularly limited.

  In the glass fiber, the kind of the glass is not particularly limited, but E glass or corrosion resistant glass containing zirconium element in the composition is preferably used in terms of quality. Note that the fiber length and fiber diameter of the glass fiber are not particularly limited as described above, and may be within a general range. For example, the fiber length is 0.1 mm to 6.0 mm, and the fiber diameter is 9.0 μm. The thing of 15.0 micrometers or less can be used above. Similarly, the average particle diameter of the non-fibrous filler is not particularly limited and may be within a general range. For example, a filler having a size of 0.1 μm or more and 500 μm or less can be used. Here, the fiber length of the fibrous filler, the fiber diameter, and the average particle diameter of the non-fibrous filler are determined with respect to the inorganic filler before being mixed with the thermoplastic resin. It is possible to analyze an image photographed by an image analysis method / particle (state) analyzer PITA-3) and calculate the weighted average.

  In the inorganic filler-containing resin composition, the content of the inorganic filler is not particularly limited, but is preferably 10 to 70% by mass, and 20 to 20 in terms of imparting more excellent impact resistance and rigidity. More preferably, it is 60 mass%, and it is still more preferable that it is 30-50 mass%.

  Further, for example, from the viewpoint that warpage can be greatly reduced while imparting impact resistance to the molded article, a fibrous filler and a non-fibrous filler can be used in combination. In that case, a particularly preferred combination includes a combination of glass fiber and glass flake. Moreover, when using together a fibrous filler and a non-fibrous filler, the total of the usage-amount of a fibrous filler and a non-fibrous filler is 50 to 100 mass parts with respect to 100 mass parts of thermoplastic resins. It is preferable that it is the range below a part. In addition, the ratio of the fibrous filler to the non-fibrous filler can be appropriately selected within a range that does not impair the object of the present invention. In addition, from the viewpoint of the effect of reducing warpage, the aspect ratio of the non-fibrous filler is preferably 1 or more and 10 or less.

[Pigment]
Examples of the pigment include a white pigment and a color pigment. And in the inorganic filler containing resin composition of this invention, in the test piece molded object of length 50mm, width 10mm, and thickness 1mm shape | molded using the resin composition, the light ray of wavelength 700nm of the thickness direction A pigment having a relatively low transmittance such that the transmittance is 8% or less is used.

  Specifically, as the white pigment, for example, at least one white pigment selected from the group consisting of titanium oxide, zinc sulfide, magnesium oxide, and barium sulfate can be selected. Among these, from the viewpoint of dielectric properties (low dielectric loss tangent), titanium oxide, zinc sulfide, or zinc oxide is preferable, zinc sulfide and zinc oxide are more preferable, and zinc sulfide is particularly preferable.

  As the pigment, any of organic and inorganic pigments required for design can be selected as appropriate. For example, in the color index (CI; issued by The Society of Dyers and Colorists), a compound classified as a pigment, specifically, a color index (CI) number is assigned. It is preferable to use what is.

  The average particle diameter of the pigment is not particularly limited and can be appropriately selected in consideration of various concealing properties, dielectric properties, fluidity when mixed with a thermoplastic resin, and the like. It is preferable that it is 1-10 micrometers. The average particle diameter of the pigment can be determined by measuring the particle diameter of the pigment particles by observation with an electron microscope and calculating the arithmetic average of the particle diameters of 1000 particles before mixing with the thermoplastic resin.

  In the inorganic filler-containing resin composition, the content of the pigment can be adjusted as appropriate so as not to deteriorate the impact resistance, but is preferably 0.4 to 12% by mass, and preferably 1.0 to 10%. It is more preferable that it is mass%, and it is especially preferable that it is 1.5-5 mass%.

  The white pigment and the pigment can be used in combination from the viewpoints of dielectric properties and design properties, but the content ratio at that time can be appropriately selected from the viewpoint of preventing the impact resistance from being deteriorated. it can.

[Others: Additives]
In the inorganic filler-containing resin composition of the present invention, additives that are usually used such as a lubricant necessary for molding can be contained as necessary. For example, additives such as antioxidants, stabilizers, nucleating agents, plasticizers, lubricants, mold release agents, hydrolysis resistance improvers, fluidity improvers, and flame retardants, organic fillers, metal fillers, A thermosetting resin etc. can be mentioned.

≪2. Molded body of inorganic filler-containing resin composition, method for producing molded body >>
The inorganic filler-containing resin composition of the present invention can be a single molded body or a molded body combined with a metal part.

  Specifically, when the inorganic filler-containing resin composition is used alone as a molded body, the molding method is not particularly limited. For example, the molded body can be obtained by a method of melt injection molding into a mold. In the case where the metal part and the resin composition are combined by injection molding to form a molded body, various methods such as insert molding, outsert molding, and hoop molding can be used. Here, when it is combined with a metal part to form a molded body, the metal part can be surface-treated in advance in order to improve the adhesion to the metal part. Note that the component to be combined is not limited to a metal, and an inorganic solid such as ceramic or glass can also be used.

  Here, in the molded object by the inorganic filler containing resin composition, in order to finally arrange the molded object into the desired shape, cutting with a normal machine tool is performed. For example, after the inorganic filler-containing resin composition is formed into a molded body by injection molding, cutting is performed in order to adjust the obtained injection molded body to a desired shape. Depending on the shape of the mold, the filling temperature, and the filling speed, the inorganic filler contained in the molded body may be oriented in the direction perpendicular to the cutting surface. When the inorganic filler is oriented by cutting the injection molded body in this way, in addition to the originally intended design, a part (cross section) of the inorganic filler is exposed to the surface of the molded body by cutting, and the molded body. There may be a case where a visually unintended design such as part of the surface is whitened is generated.

  The present invention adjusts the constituents of the inorganic filler-containing resin composition that is the raw material of the molded body, and in the molded body, by setting the color to a specific range and the light transmittance to a specific value or less, the design properties It has been found that the generation of unintended designs can be suppressed while exhibiting the above.

  Thus, since the inorganic filler-containing resin composition of the present invention has an effect of reducing the occurrence of whitening and the like by the inorganic filler when the molded body is cut, the conditions for injection molding, Regardless of cutting conditions and the like, the occurrence of unintended designs is suppressed, and as a result, the appearance of defective products is reduced.

  The application of the inorganic filler-containing resin composition of the present invention is not particularly limited. For example, as described above, impact resistance and rigidity of a casing for an electric / electronic device such as a portable terminal or a personal computer are required. At the same time, it is particularly useful as a raw material of a molded body constituting a part or all of the members that require design properties.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not limited to these Examples.

<< Examples and Comparative Examples >>
A strip-shaped test piece having a length of 50 mm, a width of 10 mm, and a thickness of 1 mm was produced by injection-molding the inorganic filler-containing resin composition and cutting the injection-molded body. The composition of the inorganic filler-containing resin composition, injection molding, and cutting conditions are as described below and in the table.

<Inorganic filler-containing resin composition>
After dry blending the following raw material components, the mixture was put into a twin-screw extruder having a cylinder temperature of 260 ° C. and melt-kneaded to obtain a pelletized inorganic filler-containing resin composition. The blending amount (parts by mass) of each component is as shown in Table 1.

[Thermoplastic resin]
-Polybutylene terephthalate (PBT): DURANEX (registered trademark), manufactured by Wintech Polymer Co., Ltd. (IV = 0.75 dL / g)

[Inorganic filler]
Glass fiber (GF): ECS03T-747 (chopped strand having a fiber length of 3 mm and a fiber diameter of 13 μm), manufactured by Nippon Electric Glass Co., Ltd.

[Pigment]
Pigment (1): Zinc sulfide pigment 1, manufactured by Nippon Pigment Co., Ltd. Pigment (2): Zinc sulfide pigment 2, manufactured by Nippon Pigment Co., Ltd. Pigment (3): Zinc oxide pigment, manufactured by Nippon Pigment Co., Ltd. 4): Carbon black, “MA600B” manufactured by Mitsubishi Chemical Corporation
Pigment (5): Zinc oxide white pigment, manufactured by Nippon Pigment Co., Ltd. (1) to (3) are beige, (4) is black, and (5) is white.

<Preparation of inorganic filler-containing resin composition molded article (strip-shaped test piece)>
Using a mold having a film gate of width 10 mm × thickness 1 mm at the end in the longitudinal direction of a cavity having a length of 50 mm, a width of 10 mm, and a thickness of 1 mm, pellets of the obtained inorganic filler-containing resin composition were injected. Molded to obtain a test piece molded body. The molding conditions are as follows.
(Molding condition)
Molding machine: Sodick TR-40VR (vertical injection molding machine)
Cylinder temperature: 260 ° C
Mold temperature: 80 ℃
Injection speed: 70mm / s
Holding pressure: 80 MPa x 5 seconds

Next, as shown in FIG. 2, the obtained test piece molded body was cut so as to be divided into two in the longitudinal direction along the substantially center line in the width direction, and then the cross section was polished and processed under the following conditions. A strip-shaped test piece having a thickness of 50 mm, a width of 5 mm, and a thickness of 1 mm was produced.
(Polishing conditions)
Equipment: “Ecomet 3” manufactured by Buehler
Abrasive paper: Curvimet # 240, # 400, # 600, UF800 and UF1200 manufactured by Buehler were used in this order.

<Evaluation of specimen>
The following evaluation was performed about the produced test piece molded object and strip-shaped test piece. Unless otherwise specified, the measurement was performed in an atmosphere of 23 ° C. and 50% RH.

[Measurement of light transmittance]
Using a spectrophotometer V-570 integrating sphere device ISN-470 manufactured by JASCO Corporation, the light transmittance of the plate surface (thickness direction) of the test piece molded body was measured at a wavelength of 700 nm.

[color]
The color difference system SE6000 manufactured by Nippon Denshoku Industries Co., Ltd. was used, and L * of the surface of the test piece molded body was measured.

[appearance]
The cross-section of the polished strip-shaped test piece was visually observed. Ten samples were prepared by the same method, and even when one unintended design was felt, it was rated as x, and when it was not felt, it was marked as ◯.

[Strength (impact resistance)]
About the produced pelletized resin composition, a Charpy impact test piece was produced by injection molding at a cylinder temperature of 260 ° C. and a mold temperature of 80 ° C., and in accordance with an evaluation standard defined in ISO 179 / 1eA under the condition of 23 ° C. Evaluation was made such that 7 kJ / m ² or more was evaluated as ◯, 5 kJ / m ² or more and less than 7 kJ / m ² as Δ, and less than 5 kJ / m ² as x.

  As is clear from the above results, the present invention can achieve both strength and designability.

Claims (6)

A resin composition containing an inorganic filler,
Including at least a thermoplastic resin, an inorganic filler, and a pigment;
When a molded specimen having a length of 50 mm, a width of 10 mm, and a thickness of 1 mm was molded from the resin composition, the light transmittance at a wavelength of 700 nm in the thickness direction of the molded body was 8% or less, and brightness L * An inorganic filler-containing resin composition having 50 to 90. The inorganic filler-containing resin composition according to claim 1, wherein the pigment is a zinc sulfide pigment. The inorganic filler-containing resin composition according to claim 1 or 2, wherein the inorganic filler is glass fiber. A molded article formed by molding the inorganic filler-containing resin composition according to any one of claims 1 to 3,
Part of the inorganic filler is exposed on the surface of the molded body. An inorganic filler-containing resin composition molded body. The inorganic filler-containing resin composition molded body according to claim 4, wherein a part of the inorganic filler exposed on the surface of the molded body is a cross section of the inorganic filler. A method for producing an inorganic filler-containing resin composition molded article according to claim 4 or 5,
A step of injection-molding an inorganic filler-containing resin composition to obtain an injection-molded body;
Cutting the injection-molded body, and a method for producing an inorganic filler-containing resin composition molded body.

Images