JP2004122367A - Insert-molded object and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insert-molded object of which the initial warpage and cracking are suppressed and the deformation or destruction is reduced even if the insert-molded object is used over a long period of time. <P>SOLUTION: The insert-molded object 1 comprises insert articles 3 and 4 made of a metal or ceramics and a thermoplastic resin foam part 2. The mean cell size of the foamed cells of the thermoplastic resin foam part 2 is not more than 50 μm. This insert-molded object can be suitably used for a use becoming a problem in warpage, heat shock resistance and heat cycle resistance because it is large-sized. <P>COPYRIGHT: (C)2004,JPO

Description

【００４４】
以上の結果から、本発明のインサート成形品はソリが小さく、耐ヒートサイクル性も優れていることが確認できた。
【００４５】
【発明の効果】
本発明によれば、インサート成形体の初期のソリ、ワレを抑制し、長期間使用しても変形や破壊が低減したインサート成形体を提供することができる。
【図面の簡単な説明】
【図１】本発明の一実施形態である自動車電装部品モジュールケースの斜視図である。
【図２】図１のＡ−Ａに添った自動車電装部品モジュールケースの部分断面図である。
【図３】（ａ）は図１のＢ−Ｂに添った自動車電装部品モジュールケースの部分断面図であり、（ｂ）は図１のＣ−Ｃに添った自動車電装部品モジュールケースの部分断面図である。
【図４】本実施形態のインサート成形体を製造する射出成形装置の概略図である。
【符号の説明】
１　自動車電装部品モジュールケース（インサート成形体）
２　熱可塑性樹脂発泡部
３、４　インサート物
５　界面
１０　射出成形装置
１１　射出成形機本体
１１１　シリンダ
１１２　スクリュー
１１３　油圧装置
１１４　加熱ヒーター
１１５　ホッパー
１１６　ノズル
１２　インサート成形用金型
１２１　固定金型
１２２　可動金型
１２３　隙間（キャビティ）
１３　超臨界状ガス導入装置
１３１　ガスボンベ
１３２　昇圧機
１３３　制御ポンプ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an insert molded article having an insert and a thermoplastic resin foam part.
[0002]
[Prior art]
In an insert molded product made of a resin and a metal, a metal having a small linear expansion coefficient is in contact with a resin or a resin composition having a large molding shrinkage or a large coefficient of linear expansion, so that a large thermal stress is generated at the interface. Therefore, immediately after molding, the shrinkage of the resin due to the molding shrinkage of the resin causes a large shrinkage of the resin thickened portion, causing warpage of the entire molded product, and in some cases, destruction of the resin portion which cannot withstand the thermal stress generated at this time. Sometimes.
[0003]
Also, when the environmental temperature changes, a large thermal stress is generated at the interface in the same manner as described above due to the difference in the linear expansion coefficient between the insert and the thermoplastic resin. Therefore, the molded article is deformed, and when the temperature change is repeated, the molded article is repeatedly deformed, and fatigue is accumulated in the resin portion, and eventually, the resin portion may be broken.
In addition, when a delicate product such as an electronic device that is weak to deformation or force is attached to the insert molded product, warpage may affect the performance of the device or destroy the device. Further, when the resin portion is broken, the device mounted inside cannot be protected from external air, water, or the like, and the reliability as a product cannot be maintained.
[0004]
In the past, such applications were addressed by improving the resin properties, for example, reducing the coefficient of linear expansion, reducing the elastic modulus, and improving the rigidity. The range of application has been limited in fields where reliability is required and in molded products having a long resin flow length in shape.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide an insert molded body in which initial warpage and cracking of the insert molded body are suppressed and deformation and destruction are reduced even after long-term use.
[0006]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to solve this problem, and as a result, applied foaming technology for forming fine foam cells to insert molding, while maintaining strength, linear expansion coefficient and rigidity, increasing fluidity, The inventors have found that by reducing the elastic modulus and the molding shrinkage, the initial warpage and cracking of the insert molded body can be suppressed, and as a result, deformation and destruction can be significantly reduced even after long-term use, and the present invention has been made.
[0007]
According to the present invention, there is provided an insert molded body comprising a metal or ceramic insert and a thermoplastic resin foam portion, wherein the average cell diameter of the foam cells of the thermoplastic resin foam portion is 50 μm or less. An insert molding is provided.
According to the present invention, there is provided an insert molding method for molding an insert formed from an insert and a thermoplastic resin foam portion, wherein the insert is placed in one of a fixed mold and a movable mold. Thereafter, the movable mold is closed with respect to the fixed mold, and then the foamable molten resin in which the supercritical gas is dissolved is filled in a cavity formed between the mold-closed insert and the inner surface of the mold. A method for producing an insert molded body, which is characterized by injection and foaming, is provided.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
The insert molded article of the present invention has an insert and a thermoplastic resin foam part.
The thermoplastic resin that can be used for the thermoplastic resin foam portion can be appropriately selected according to the use environment and use of the insert molded body. For example, olefin resins such as polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-propylene-diene copolymer, ethylene-vinyl acetate copolymer, polybutene, chlorinated polyethylene, polystyrene, syndiotactic polystyrene, styrene- Acrylic resin such as butadiene-styrene copolymer, styrene-isoprene-styrene resin, polymethyl acrylate, ethylene-ethyl acrylate copolymer, chlorine resin such as polyvinyl chloride, fluorine resin such as polyfluoroethylene, 6 -Polyamide resins such as nylon, 6,6-nylon and 12-nylon, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, ABS resins, polycarbonate, polyacetal, polyphenylene sulfide , Polyether ether ketone, polyether imide, polyether nitrile, polyarylene, polysulfone, polyether sulfone, polyimide, LCP, silicone resin, thermoplastic urethane, thermoplastic resins such as various elastomers.
[0009]
Preferably, polyamide resin such as syndiotactic polystyrene, 6-nylon, 6,6-nylon, 12-nylon, etc., since it is excellent in heat resistance and low warpage and can be suitably used for electric parts for automobiles and the like, Polyester resins such as polyethylene terephthalate, polybutylene terephthalate, ABS resin, polycarbonate, polyacetal, polyphenylene sulfide, polyetheretherketone, polyetherimide, silicon resin, polyethernitrile, polyarylene, polysulfone, polyethersulfone, Engineering plastics such as polyimide and LCP. Particularly, polyphenylene sulfide and syndiotactic polystyrene are preferable.
[0010]
The above-mentioned thermoplastic resins may be used alone or in an alloy state, a blend state or a composite state using two or more kinds.
Further, in addition to the thermoplastic resin, a resin to which a thermoplastic elastomer, an inorganic filler, and the like are added as auxiliary components may be used. For example, fibrous fillers such as glass fibers and carbon fibers, granular fillers such as calcium carbonate, silica and glass beads, plate-like fillers such as glass flakes, mica, clay and talc, whiskers and the like may be added. Hereinafter, in the present specification, the meaning of the thermoplastic resin includes a composition containing the above-mentioned auxiliary components.
[0011]
Examples of the material constituting the insert of the insert molded article of the present invention include metals such as aluminum, copper, aluminum alloy, stainless alloy, stainless steel, iron, gold, silver, brass, and zinc, and linear expansion equivalent to these metals. Coefficient materials, ceramics such as silicon carbide, alumina, and nitride ceramics, as well as silicon semiconductors, chip capacitors, chip resistors, and coils. Preferred are copper, aluminum, iron, alumina, silicon semiconductor, chip capacitors, and coils.
[0012]
The shape of the insert can be appropriately selected depending on the application. For example, when used for automotive electrical component cases such as inverter cases and ECU cases, the shapes of frames, flat plates, bars, and cylinders are preferable, and when used for electronic components such as semiconductor encapsulation, passive component encapsulation, sensors, and coils. Examples of the shape include a chip shape, a wire shape, a winding shape and the like in addition to a flat shape.
[0013]
The foam cell of the thermoplastic resin foam part of the insert molded article of the present invention needs to have an average cell diameter of 50 μm or less. If the average cell diameter exceeds 50 μm, warpage of the insert molded body may increase, or the difference in linear expansion coefficient between the insert and the resin foamed portion may increase, resulting in peeling, cracking, and the like.
Preferably, the average cell diameter is 40 μm or less, particularly preferably 5 to 30 μm.
Most of the cross section of the foam cell is a circle, an ellipse, or a shape close thereto. In this specification, the cell diameter means the major axis of the cell. The average cell diameter can be determined by taking a cross section of the foamed part in an electron micrograph, taking the photograph into an image processor, and performing binarization processing.
[0014]
The weight reduction rate of the thermoplastic resin foamed part is preferably 2% or more. Particularly, it is preferably 5 to 20%, more preferably 10 to 15%. When the weight reduction ratio is less than 2%, even if the average cell diameter is 50 μm or less, there is a risk that the warpage of the insert molded body becomes large, the insert and the resin foamed portion are separated, and cracks are generated. is there.
Here, the weight reduction ratio is defined by the following equation, when the density ρ of the resin material used for the foamed portion when it is not foamed and the density ρ ′ of the foamed portion are defined.
Lightening rate = 100 [1- (ρ ′ / ρ)] (%)
[0015]
In the insert molded article of the present invention, the linear expansion coefficient α of the foamed portion is preferably 100 (α−β) / β within ± 100% of the linear expansion coefficient β of the insert.
In addition, the coefficient of variation, 100 (α−γ) / γ, is preferably within ± 30% with respect to the coefficient of linear expansion γ of the thermoplastic resin forming the foamed portion in the unfoamed state.
Here, if 100 (α-β) / β is out of the range of ± 100%, the difference in linear expansion coefficient between the insert and the resin foamed portion becomes large, and peeling, cracking, and the like may occur. Preferably it is ± 20%. The same applies when 100 (α−γ) / γ exceeds the range of ± 30%.
[0016]
Since the insert molded body of the present invention is large, such as an inverter case and an ECU case, it is particularly warped, and there is a problem with electric component parts for automobiles where heat shock resistance and heat cycle resistance are problematic, semiconductor encapsulation, and passive component encapsulation. , Sensors, coils, and other electronic components.
[0017]
Hereinafter, as an embodiment of the insert molded body of the present invention, an automotive electrical component module case will be described with reference to the drawings.
FIG. 1 is a perspective view of an automotive electrical component module case which is an embodiment of the insert molded product of the present invention. 2 is an enlarged partial cross-sectional view of the module case along line AA in FIG. 1, and FIG. 3A is an enlarged partial cross-sectional view of the module case along line BB in FIG. FIG. 3B is an enlarged partial cross-sectional view taken along line CC of the module case in FIG. 1.
[0018]
The module case 1 includes a thermoplastic resin foam part 2, an insert 3, and an insert 4.
The thermoplastic resin foam part 2 is a foam of a polyphenylene sulfide resin composition, and is foamed using a known chemical foaming agent or physical foaming agent. More preferably, a foam having an average cell diameter of 50 μm or less is preferred in consideration of the dimensional stability after insert molding and the like, in which the decrease in strength and rigidity is small.
The average cell diameter of the foam part 2 of the module case 1 is 20 μm.
The insert 3 is a copper: nickel-plated copper frame, which is in contact with the thermoplastic resin foam part 2 at the interface 5, and a part of which is included in the thermoplastic resin foam part 2.
The insert 4 is a copper: nickel-plated copper frame, which is in contact with the thermoplastic resin foam portion 2 at the interface 5 and has an entire periphery in the CC cross section except a part in the BB cross section. , Covered with a thermoplastic resin foam part 2.
[0019]
In a conventional insert molded body, peeling or deformation occurs at the interface 5 due to a difference in physical properties such as a linear expansion coefficient between the inserts 3 and 4 and the thermoplastic resin foamed portion 2.
In contrast, the thermoplastic resin foamed portion 2 has a fine foamed structure as in the present embodiment, so that the above-described problem can be solved and the initial warpage and cracking can be suppressed. Deformation and destruction can be significantly reduced.
[0020]
The method for producing an insert molded article of the present invention may be any method as long as it is insert molding and can reduce the average cell diameter of the foamed thermoplastic resin portion to 50 μm or less. Preferably, a method in which a gas inactive to a resin material is converted into a supercritical gas, and a material dissolved or mixed in a thermoplastic resin is foamed by decompression and cooling is used.
[0021]
A method and an apparatus for producing a closed foam by infiltrating a supercritical gas into a resin composition include a step of shaping the composition, and after infiltrating the supercritical gas into a molded body, degassing is performed. There are a batch type foaming method in which the foaming step is a separate step, and a continuous type foaming method in which the shaping step and the foaming step are continuously performed. For example, molding methods and manufacturing apparatuses described in U.S. Pat. No. 5,158,986 and JP-A-10-230528 can be used.
Here, the supercritical gas is a fluid that exhibits intermediate properties between a gas state and a liquid state. A gas becomes a supercritical gas when it exceeds a temperature and pressure (critical point) determined by its type. The supercritical gas has such a property that the permeation power into the resin is stronger than that in the liquid state and is uniform.
[0022]
Hereinafter, the method for producing an insert molded body of the present invention will be described in detail with reference to the drawings.
FIG. 4 is a schematic diagram of an injection molding apparatus for manufacturing the insert molded body of the present embodiment.
The injection molding apparatus 10 includes an insert molding die 12 (hereinafter, may be simply referred to as a die) and an injection molding machine that is located below the die 12 and supplies a molten thermoplastic resin to the die 12. It comprises a main body 11 and a supercritical gas introduction device 13 for introducing a supercritical gas into the injection molding machine main body 11.
[0023]
The injection molding machine main body 11 includes a cylinder 111, a screw 112 rotating in the cylinder 111 to mix and extrude the material, a hydraulic device 113 for moving the screw 112 forward and backward, and heating the cylinder 111 to melt the resin. The main components are a heater 114 and a hopper 115 for supplying a resin as a raw material into the cylinder 111.
The thermoplastic resin supplied from the hopper 115 moves in the cylinder 111 by the rotation of the screw 112, and is heated and melted by the heater 114. And it is supplied toward the metal mold 12 by the advance of the screw 112.
[0024]
The insert molding die 12 is located above the injection molding machine main body 11 and is connected to the fixed die 121 connected to the nozzle 116, and is located above the fixed die 121. It has a movable mold 122 that can move up and down in the vertical direction. The movable mold 122 is moved forward and backward by a mold clamping device (not shown). A gap 123 (cavity) for injecting a molding material in a molten state and shaping it into a predetermined shape is formed on the contact surface between the fixed mold 121 and the movable mold 122.
The plasticized resin containing the supercritical gas injected from the injection molding machine main body 111 is filled in the gap 123 (cavity), and the filled resin is formed into the shape of the gap 123.
[0025]
The insert molding die 12 is preferably a heat-insulating die because silver and the like hardly occur in the insert molded body and the appearance is improved. Examples of such a heat-insulating mold include a heat-insulating material that does not melt and break at the molding temperature of the resin used for the foamed portion, for example, a porous ceramic coating on both inner surfaces of the fixed mold 121 and the movable mold 122. . When the molding temperature of the raw material resin is low, for example, a mold in which a polyethylene terephthalate film is adhered to the inner surface of the mold is actually a heat insulating mold.
[0026]
It is to be noted that, as in the present embodiment, the use of an insert molding apparatus having a movable mold that moves up and down in the vertical direction with respect to the fixed mold prevents misalignment of the insert, and provides a highly accurate insert molded body. Is preferred.
This is because even if the displacement is slight, it is difficult to stably express the intended product function.
[0027]
The supercritical gas introduction device 13 includes a gas cylinder 131 serving as a source gas supply source, a booster 132 that increases the pressure of the gas supplied from the gas cylinder 131 to a critical pressure, and a cylinder of the supercritical gas that has been increased to the critical pressure. There is a control pump 133 for controlling the amount of introduction into 111.
The supercritical gas introduction device 13 is connected to the cylinder 111 and supplies the supercritical gas to the cylinder 111.
[0028]
Note that the injection molding apparatus 10 is different from a normal injection molding machine in that a supercritical gas introduction device is provided. That is, the molding apparatus used in the manufacturing method of the present invention is a known insert molding die drive and control device, except for a device for dissolving and mixing a supercritical gas in a thermoplastic resin and injecting the mixture into a mold. Can be used.
[0029]
Next, a method for manufacturing an insert molded body according to the present embodiment will be specifically described. First, an insert is inserted and fixed to the inner surface of the fixed mold 121, and the movable mold 122 is moved to clamp the mold.
The insert may be fixed to the inner surface of the movable mold 122.
[0030]
Next, the cylinder 111 is preheated, and the surface temperature of the mold 12 is kept within a range of ± 20 ° C. of the crystallization temperature of the thermoplastic resin as a raw material. After that, the thermoplastic resin is put into the cylinder 111 via the hopper 115.
Next, the gas cylinder 131 is opened, and the pressure of the gas is raised to a critical pressure or higher, preferably 15 MPa, more preferably 20 MPa or higher by the booster 132.
Examples of the gas that can be used in the present invention include an inert gas such as carbon dioxide, nitrogen, air, oxygen, hydrogen, and helium, and carbon dioxide or nitrogen is particularly preferable.
The control pump 133 is opened, and the supercritical gas is introduced into the cylinder 111 to permeate the plasticized thermoplastic resin (permeation step). Here, the pressurized gas immediately rises in temperature when it is dissolved and mixed in the high-temperature thermoplastic resin, and becomes a supercritical gas.
At this time, the amount of the supercritical gas to be permeated is determined according to the desired expansion ratio, but is 0.1 to 20 parts by weight, preferably 1 to 10 parts by weight based on 100 parts by weight of the thermoplastic resin. Let penetrate.
The time for infiltrating the supercritical gas may be generally 10 seconds to 10 minutes.
[0031]
In order to infiltrate the supercritical gas into the thermoplastic resin, the temperature of the resin is, for example, in the case of using a crystalline resin polyarylene sulfide and / or syndiotactic polystyrene, the temperature in the gas atmosphere in the injection kneader. , The melting point of the resin (Tm) to (Tm + 50 ° C.). When the temperature in the gas atmosphere is lower than the melting point, molding becomes difficult due to insufficient melting and kneading of the resin composition. When the temperature is higher than (Tm + 50) ° C., decomposition of the resin may occur.
[0032]
Next, the screw 112 is advanced, and the thermoplastic resin containing the supercritical gas in the cylinder 111 is introduced into the gap 123 in the mold 12 maintained at the above temperature (introduction step).
At this time, mold clamping or counter pressure is applied so that the supercritical gas mixed with the thermoplastic resin can maintain the supercritical state until the introduction of the mixture into the gap 123 is completed. (Critical state maintaining step).
[0033]
Thereafter, the pressure applied to the filled resin is reduced, so that the thermoplastic resin can be foamed. In consideration of foaming, it is sufficient to lower the pressure below the critical pressure of the infiltrated gas. However, it is usual to lower the pressure to normal pressure, and it is usual to cool the gas at the same time as the pressure reduction.
Specifically, a skin layer is formed on the surface of the thermoplastic resin in contact with the inner surface of the mold 12, and while the inside is in a molten state, the movable mold 122 is retracted (core back) and degassing is performed. (Pressure reduction step). The method of retracting the movable mold 122 is preferable because poor foaming in the vicinity of the gate hardly occurs and a uniform foamed structure can be provided.
[0034]
There are various methods for reducing the pressure. For example, if a so-called short shot in which the mixture is filled less than the volume of the gap 123 is performed, the pressure immediately drops when the filling is completed. In this method, surface accuracy is usually difficult to obtain.
The pressure in the mold may be reduced by providing a device for introducing gas into the mold. In this case, a pressure of 10 to 200 kg / cm ² is previously injected into the mold, and the pressure in the mold is reduced by removing the gas after injecting the raw material. However, a device for introducing gas must be attached to the mold, and in particular, when resin is impregnated with supercritical gas for injection molding, two systems for introducing gas must be provided. There is a problem that the device becomes large. On the other hand, if the pressure in the mold 12 is reduced by retreating the movable mold 122 in the mold 12, it is possible to prevent the apparatus from being enlarged.
[0035]
The pressure in the mold may be reduced by reducing the mold clamping pressure.
Further, the pressure in the mold does not have to be reduced. This is because the pressure applied to the raw material at the time when the material is injected from the nozzle into the mold rapidly decreases, so that the foaming can be performed without reducing the pressure in the mold.
[0036]
The surface temperature of the mold 12 is preferably maintained at least within a range of ± 20 ° C. of the crystallization temperature of the thermoplastic resin until the movable mold is retracted. When the pressure is reduced at a temperature outside this temperature range, the cell diameter becomes large and coarse foaming is generated, or even if the foaming is uniform, the crystallization of the resin composition is insufficient and strength and rigidity may be reduced. .
[0037]
Thereafter, the mold is cooled and solidified. After a predetermined cooling time has elapsed, the mold 12 is opened by retracting the movable mold 122 upward, and the insert molded body is taken out.
The insert molded body thus obtained has an average cell diameter in the foamed portion of 50 μm or less, a linear expansion coefficient reduced to a level close to that of the insert, and a surface glossiness of 80% or more. Become.
[0038]
It should be noted that the present invention is not limited to the above-described embodiment, but includes modifications and improvements as long as the object of the present invention can be achieved.
For example, the present invention can be applied to an insert die in which a movable die moves left and right, if attention is paid to preventing displacement of an insert.
[0039]
The mold is a heat-insulating mold having a heat-insulating material attached to the surface. However, the present invention is not limited to this, and the mold itself may be formed of a heat-insulating material having excellent heat resistance and used as a heat-insulating mold. Further, although the mold is a heat-insulating mold, the adjustment may be performed by providing a heater and a cooling unit in a normal mold having no heat-insulating performance, and repeatedly turning on and off each of them frequently. However, in this case, it takes time to adjust the temperature. On the other hand, if a heat-insulating mold is used, the surface of the mold can be easily maintained at a predetermined temperature.
[0040]
【Example】
The automobile electrical component module case of FIG. 1 was manufactured based on the manufacturing method described in the above embodiment.
In addition, evaluation of the manufactured insert molded body was performed by the following method.
(1) Average cell diameter of the foamed part of the molded article: I. H image ver. Image processing was performed using 1.57 to convert the actual cell shape into an elliptical shape having the same area, and the major axis was used as the cell diameter.
(2) Foaming state The uniformity of the foaming (cell) was evaluated by taking an observation photograph (magnification: 500 times) with a scanning electron microscope (SEM).
(3) A sample of 12 × 6 × 3.2 (unit mm) was cut out from the center of a bending test piece conforming to ASTM from the linear expansion coefficient composition and the insert, and measured by a method specified in ASTM E831. .
The MD direction refers to the flow direction of the resin, and the TD direction refers to the vertical direction of the flow direction of the resin.
(4) Amount of warpage When the molded product was allowed to stand on a horizontal surface, the distance at which both ends of the molded product were separated from the horizontal plane was measured, and the average value of the measured values at both ends was defined as the amount of warpage.
(5) Heat cycle resistance The insert molded body was subjected to 1000 cycles of changing the temperature from −40 ° C. × 30 minutes to 150 ° C. × 30 minutes, and then visually evaluated for the occurrence of cracks in the molded body.
[0041]
Example 1
As a thermoplastic resin, 50% by weight of polyphenylene sulfide (manufactured by DIC Corporation: T-3, 310 ° C., melt viscosity at 1200 / s: 100 PaS: hereinafter, PPS-1) and glass fiber (manufactured by Asahi Fiber Glass, JAFT591) A composition mixed with 50% by weight was used and charged into an injection molding machine through a hopper.
As the insert, a copper: nickel plated copper frame was used.
The molding conditions were a resin temperature of 300 ° C. and a mold temperature of 135 ° C.
Nitrogen was used as a supercritical gas, and injection was performed at 20 MPa, and the measured value and the gas flow rate were controlled so as to be 0.5 parts by weight based on the mixture.
The retraction of the movable mold was adjusted so that the weight reduction rate of the obtained molded body was 2%, and PPS-1 was foamed to obtain an insert molded body.
[0042]
Example 2-9, Comparative Example 1-6
An insert molded body was manufactured in the same manner as in Example 1 except that the compositions shown in Table 1 were used and the retraction of the movable mold was adjusted so as to obtain a predetermined light weight ratio.
In Comparative Examples 1, 3, and 5, no injection of nitrogen gas was performed, and a molded product was manufactured by insert injection molding without retreating the movable mold even after the composition was filled.
Table 1 shows the results of evaluating the composition and physical properties of the insert molded bodies produced in Example 1-9 and Comparative Example 1-6.
[0043]
[Table 1]

[0044]
From the above results, it was confirmed that the insert molded product of the present invention had small warpage and excellent heat cycle resistance.
[0045]
【The invention's effect】
Advantageous Effects of Invention According to the present invention, it is possible to provide an insert molded body in which initial warpage and cracking of the insert molded body are suppressed and deformation and destruction are reduced even when used for a long period of time.
[Brief description of the drawings]
FIG. 1 is a perspective view of an automotive electrical component module case according to an embodiment of the present invention.
FIG. 2 is a partial cross-sectional view of the motor vehicle electrical component module case along AA in FIG. 1;
3A is a partial cross-sectional view of the motor vehicle electrical component module case along the line BB in FIG. 1; FIG. 3B is a partial cross-sectional view of the motor vehicle electrical component module case along the line CC in FIG. 1; FIG.
FIG. 4 is a schematic view of an injection molding apparatus for producing an insert molded body of the present embodiment.
[Explanation of symbols]
1 Automotive electrical component module case (insert molded body)
2 Thermoplastic resin foam part 3, 4 Insert 5 Interface 10 Injection molding device 11 Injection molding machine main body 111 Cylinder 112 Screw 113 Hydraulic device 114 Heater 115 Hopper 116 Nozzle 12 Insert molding die 121 Fixed die 122 Movable die 123 gap (cavity)
13 Supercritical gas introduction device 131 Gas cylinder 132 Booster 133 Control pump

Claims (9)

An insert molded article comprising a metal or ceramic insert and a thermoplastic resin foamed part, wherein the average cell diameter of the foamed cells of the thermoplastic resin foamed part is 50 μm or less. The insert molded body according to claim 1, wherein the thermoplastic resin foamed part is polyphenylene sulfide and / or syndiotactic polystyrene. The insert molded body according to claim 1 or 2, wherein the weight reduction rate of the thermoplastic resin foamed portion is 2% or more.
Lightening rate = 100 [1- (ρ ′ / ρ)] (%)
[Ρ ': Density of foamed thermoplastic resin, ρ: Density of thermoplastic resin (when not foamed)] The insert molded body according to claim 1 or 2, wherein a weight reduction rate of the thermoplastic resin foamed portion is 5 to 20%. The coefficient of linear expansion α of the foamed thermoplastic resin is 100 ± (α−β) / β within ± 100% of the coefficient of linear expansion β of the insert. The insert molded body according to any one of claims 1 to 4, wherein a variation rate of 100 (α-γ) / γ is within ± 30% of a linear expansion coefficient γ of the plastic resin in an unfoamed state. The insert molded product according to any one of claims 1 to 5, wherein the insert molded product is an electronic component case or an electronic component for an automobile. An insert molding method for molding an insert molded body comprising an insert and a thermoplastic resin foamed part, wherein the movable mold is provided after installing the insert in one of a fixed mold and a movable mold. The mold is closed with respect to the fixed mold, and then a foamable molten resin in which a supercritical gas is dissolved is injected into a cavity formed between the insert and the inner surface of the mold. A method for producing an insert molded body, characterized by foaming. The method for manufacturing an insert molded product according to claim 7, wherein the opening and closing directions of the fixed mold and the movable mold are vertical. An automotive electrical component case or electronic component comprising an insert molded body comprising a metal or ceramic insert and a thermoplastic resin foam.

Images