JPH1052845A - Method for reaction injection molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control temp. of an inserting body in a mold and to improve adhesiveness between the inserting body and a resin by a method wherein current is passed in the inserting body in the mold from the outside and electric power fed in the inserting body is changed in accordance with change in resistance caused by change in temp. of the inserting body and reaction injection molding is performed. SOLUTION: An inserting body 20 is arranged in a mold 22 and at the same time when current is passed the inserting body 20, the current in the inserting body 20 is monitored by means of an ammeter 32. Then, when temp. of the inserting body 20 is decreased too lower than a specified temp, as resistance of the inserting body 20 is decreased, electric current detected by the ammeter 32 is increased at the same electric voltage. Therefore, in this case, a signal is transmitted to a controlling means 36 from the ammeter 32 to increase electric voltage applied from a variable voltage electric source 30. At the same time when temp. of the inserting body 20 is controlled like this, a reaction stock soln. is fed into a cavity from an inlet hole to perform reaction injection molding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reaction injection molding method, and more particularly to a reaction injection molding method for forming a molded product having a part of an insert exposed from the molded product by reaction injection molding.

[0002]

2. Description of the Related Art Reaction injection molding (hereinafter also referred to as RIM).
In the method, two reaction stock solutions are mixed in a mixing chamber, fed into a cavity of a mold, and injection-molded while reacting in the mold. This RIM method is suitably used when a polymer (molded article) is formed from a norbornene-based monomer.

In order to form a molded product in which a part of the metal insert is exposed from the molded product, for example, by using the RIM method, a part of the metal insert is placed inside the mold. The insert is placed so as to be exposed to the outside and reaction injection molding is performed in a mold.

[0004]

However, in such reaction injection molding, the heat of reaction in the vicinity of the metal insert is absorbed by the metal insert, and the resin cannot be sufficiently cured. Since the body and the resin did not adhere to each other, the characteristics of the molded product were sometimes unstable. In order to prevent such inconvenience, a method of heating the metal insert in advance and disposing it in a mold may be adopted.

[0005] However, in such a method, it is difficult to keep the degree of heating constant, or if molding is performed after a certain period of time has elapsed after heating, the metal insert is cooled, There is a problem that the effect is lost. Further, if the time after heating is not constant, the temperature of the metal insert varies, so that there is also a problem that a molded product of constant quality cannot be obtained.

As disclosed in Japanese Patent Application Laid-Open No. 49-63553, a method has been proposed in which a metal insert is energized to generate heat when a cured resin such as an epoxy resin is molded.
In this method, it is difficult to control the temperature, and it is also difficult to obtain a molded product of a constant quality. Especially,
In reaction injection molding, it is necessary to promote the reaction well and take care that the temperature does not rise excessively due to the heat of the reaction. In order to obtain high quality molded products, controlling the temperature inside the mold is an important factor. Met. However, in the conventional reaction injection molding technique, the temperature of the mold itself can be controlled, but there is no technique capable of controlling the temperature of the insert disposed in the mold.

[0007] In addition, the wound coil, particularly the ground coil of the linear motor for magnetic levitation, is laid outdoors, so that it is subjected to severe environmental changes in the surroundings and electromagnetic force repeatedly applied as the vehicle passes. You need to endure. The present invention has been made in view of such a situation, and enables temperature control of an insert placed in a mold, and has good adhesion between the insert and a resin, and is a reaction injection molded product of a certain quality. It is an object of the present invention to provide a reaction injection molding method capable of producing a polymer.

[0008]

Means for Solving the Problems To achieve the above object, a reaction injection molding method according to the present invention comprises:
An insert that can be energized from the outside is arranged, and while current is applied to the insert from the outside of the mold, a resistance change due to a temperature change of the insert is detected and supplied to the insert according to the resistance change. The reaction injection molding is performed in the mold while controlling the temperature of the insert body by changing the power to be applied.

The reaction stock solution used in reaction injection molding includes:
Although not particularly limited, for example, urethane-based, urea-based, nylon-based, epoxy-based, unsaturated polyester-based, phenol-based, and norbornene-based, and the like, as general molding conditions, the reaction solution temperature is 20 to 80 ° C, The viscosity of the reaction stock solution is, for example, 5 cps to 300 at 30 ° C.
0 cps, preferably about 100 cps to 1000 cps.

In such molding, a reinforced polymer (molded article) can be produced by placing a reinforcing material in a mold in advance and supplying a reaction liquid therein to polymerize. Examples of the reinforcing material include glass fiber, aramid fiber, carbon fiber, ultrahigh molecular weight polyethylene fiber, metal fiber, polypropylene fiber, aluminum coated glass fiber, cotton, acrylic fiber, boron fiber, silicon carbide fiber, alumina fiber and the like. be able to. However, in the case of the induction repulsion type coil, non-conductive reinforcing materials such as glass fiber, aramid fiber, ultra high molecular weight polyethylene fiber, polypropylene fiber, cotton, acrylic fiber, boron fiber, silicon carbide fiber, and alumina fiber are preferable.

Further, these reinforcing materials are formed by matting a long fiber or chopped strand.
It can be used in various shapes, such as those woven into a cloth and those in a chop shape. These reinforcements
The surface of which is treated with a coupling agent such as a silane coupling agent is preferable from the viewpoint of improving the adhesion to the resin. The amount is not particularly limited, but is usually at least 10% by weight, preferably 20 to 60% by weight, based on the total amount of the reaction stock solution.

Further, various additives such as an antioxidant, a filler, a pigment, a colorant, a foaming agent, a flame retardant, a sliding agent, an elastomer, a dicyclopentadiene-based thermopolymerized resin and a hydrogenated product thereof are compounded. Thereby, the properties of the obtained polymer can be modified. Antioxidants include various plastics such as phenolic, phosphorus, and amine
There are antioxidants for rubber.

Fillers include milled glass, carbon black, talc, calcium carbonate, aluminum hydroxide, mica, and the like, and whisker inorganic fillers such as potassium titanate and calcium sulfate. Examples of the elastomer include natural rubber, polybutadiene, polyisoprene, styrene-butadiene copolymer (SBR), styrene-butadiene-styrene block copolymer (SBS), and styrene-isoprene-styrene block copolymer (SI
S), an ethylene-propylene-dienter polymer (E
PDM), ethylene vinyl acetate copolymer (EVA), and hydrides thereof.

The additive is usually mixed in advance with one or both of the reaction solutions. The mold main body used for the reaction injection molding does not necessarily have to be a rigid and expensive mold, and is not limited to a metal mold, but may be a resin mold or a simple mold. This is because reaction injection molding can be performed at a relatively low temperature and a low pressure by using a low viscosity reaction liquid. The inside of the mold is sealed with an inert gas, and the components used for the polymerization reaction are stored under an inert gas atmosphere such as nitrogen gas.
And it is preferable to operate.

The mold temperature is preferably from 10 to 150
° C, more preferably 30 to 120 ° C, still more preferably 50 to 100 ° C. The temperature control of the mold can be performed by providing a passage for the heat medium in the mold and circulating the heat medium. Mold pressure is usually 0.1-1
It is in the range of 00 kg / cm ² . The polymerization time may be appropriately selected, but is usually 30 seconds to 20 seconds after the completion of the injection of the reaction solution.
Minutes.

In the present invention, the insert is not particularly limited as long as it can be energized. For example, a metal such as a coil, a metal rod, a metal plate, a metal mesh or a conductive resistor is used. The current or voltage flowing through the insert changes according to the resistance of the insert. The resistance of the insert changes depending on the temperature of the insert. In a normal conductive insert, the higher the temperature, the higher the resistance (positive characteristics), but some have a lower resistance as the temperature increases (negative characteristics). In any case, the resistance of the insert changes according to the temperature of the insert.

Therefore, the insert is disposed inside the mold, and in a state where the mold is closed, power is supplied to the insert from the outside of the mold to generate heat, and the voltage or current applied to the insert is reduced. By monitoring, a change in resistance of the insert can be detected, and the temperature of the insert can be predicted from the change in resistance. If the power supplied to the insert is adjusted based on the predicted temperature of the insert, the temperature of the insert can be controlled.

The temperature of the insert is preferably between 10 and 15
It is desirable to control the temperature to be about 0 ° C, more preferably about 30 to 120 ° C, and still more preferably about 50 to 100 ° C. In the reaction injection molding according to the present invention, not only the mold, but also the temperature control of the insert inserted into the mold becomes possible, so that the reaction in the portion in contact with the insert proceeds well, and the insert and the resin And the adhesiveness with the adhesive becomes good. Further, even after the mold is closed, the temperature of the insert can be controlled to be constant, so that a reaction injection molded product of a constant quality can be always obtained.

In the case where the insert is a conductive coil, for example, an induction repulsion type magnetic levitation type ground coil for a railway, current heating can be performed with the insert set in a molding die. Compared with the heating method, it is easier to control the temperature during the injection of the resin, and it is possible to stabilize the molding quality. In addition, since there is no movement of the conductive coil from the preheating equipment to the molding equipment, mass production efficiency is good and the molding cost can be reduced.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic structural view of an apparatus used for reaction injection molding according to an embodiment of the present invention, FIG. 2 is a perspective view of an insert shown in FIG. 1, and FIG. 3 is a perspective view of a mold shown in FIG. As shown in FIGS. 1 and 3, the mold 22 according to the present embodiment has an upper mold and a lower mold, and the split surfaces 25 are combined with each other to form a flat plate-shaped cavity 24. Is formed. Although FIGS. 1 and 3 show only the lower mold, the same applies to the upper mold.

As shown in FIG. 3, the mold 22 of this embodiment
Has a mold body 26 and an elastic member 28. The mold main body 26 is not limited to a metal mold and is made of a rigid material such as a resin mold or a simple mold. The mold body 26 has a protruding portion 20a which is a part of the insert 20 shown in FIG.
(Refer to FIG. 1)
7 is formed, and an elastic member 28 is mounted in the notch 27.

The elastic member 28 is mounted on the notch 27 so that the groove 29 is formed without filling the entire notch 27. Means for attaching the elastic member 28 to the notch 27 is not particularly limited, but a method using adhesion is preferable. The inner diameter of the groove 29 is set smaller than the outer diameter of the protruding portion 20a of the insert 20 shown in FIGS. For example, as shown in FIG. 1, in a state where the protruding portion 20 a of the insert 20 is pressed into the groove 29 of the elastic member 28, the elastic member 28 is elastically compressed and deformed to about 0.3 to 3 mm in the radial direction. The size of the groove 29 is determined. The groove 29 may be formed by cutting or the like.

In this embodiment, the elastic member 28 is made of plate-like silicon rubber having excellent heat resistance. The thickness t of the elastic member 28 (the thickness between the groove 29 and the notch 27) is a minimum part thereof, preferably 3 mm or more, more preferably 5 mm or more, and particularly preferably 7 mm or more. The upper limit of the thickness is preferably 20 mm or less, more preferably 15 mm or less. If the minimum thickness t is too small, sufficient elasticity may not be obtained as the elastic member 28. If the minimum thickness t is too large, it is not preferable in terms of accuracy of the outer shape of the reaction injection molded article. The elastic member 28 is not particularly limited as long as it has an appropriate elasticity, is not affected by the reaction solution used for the reaction injection molding, and does not fuse with the obtained molded body.

The insertion body 20 shown in FIG.
And the protruding portion 20a.
0b is constituted by a coil or the like, and the protruding portion 20a is constituted by a terminal for the coil or the like. A flow path for a heat medium (not shown) is formed in the mold 22 so that the mold 22 can be heated or cooled to a predetermined temperature.

As shown in FIG. 1, outside the mold 22,
A wiring 34 connectable to the protruding portion 20a (terminal) of the insert 20 is arranged. The variable voltage power supply 30
And the ammeter 32 are connected in series. Variable voltage power supply 3
0 is a device for supplying power to the insert 20;
It is configured so that the applied voltage can be changed. The ammeter 32 can measure the current supplied to the insert 20.

In this embodiment, the variable voltage power supply 30 is controlled by control means 36 such as a computer. At the time of reaction injection molding, first, the insert 20 is set in the mold 22. At this time, the insert 20 is arranged so that the protruding portion 20 a of the insert 20 fits into the groove 29 of the mold 22. The mold 22 is closed, the wiring 34 is connected to the protruding portion 20a of the insert 20, and the insert 2
0 to generate heat in the insert 20.

At the same time as the power is supplied to the insert 20, an ammeter 32
Monitor the current flowing to the insert 20. For example, when the insert 20 is a resistor having a positive characteristic, the insert 2
If the temperature of 0 is excessively higher than the predetermined temperature, the resistance increases, and under the same voltage condition, the current measured by the ammeter 32 decreases. Therefore, in that case, a signal is sent from the ammeter 32 to the control means 36 to reduce the voltage applied from the power supply 30. As a result, the power supplied to the insert 20 decreases, and an excessive rise in temperature of the insert 20 can be suppressed.

When the temperature of the insert 20 is too low than the predetermined temperature, the resistance of the insert 20 decreases, so that the current detected by the ammeter 32 increases at the same voltage. Therefore, in that case, a signal is sent from the ammeter 32 to the control means 36 to increase the voltage applied from the variable voltage power supply 30. As a result, the power supplied to the insert 20 increases, and an excessive decrease in the temperature of the insert 20 can be suppressed. The relationship between the resistance value and the temperature in the insert 20 is measured in advance by an experiment or the like, and the data is stored in the control means 36.

Simultaneously with such temperature control of the insert 20, a reaction solution is injected into the cavity 24 from an injection port (not shown), and reaction injection molding is performed. When the reaction injection molding is a reaction injection molding using a norbornene-based monomer, the monomers used in this example are dicyclopentadiene, dihydrodicyclopentadiene,
It is a cycloolefin having a norbornene ring such as tetracyclododecene and tricyclopentadiene.

A metathesis catalyst that can be used in reaction injection molding using a norbornene-based monomer is
Any metathesis catalyst known as a bulk polymerization catalyst for norbornene-based monomers such as organic molybdates such as tungsten hexachloride, tridodecylammonium molybdate and tri (tridecyl) ammonium molybdate, and organic ammonium molybdate such as ammonium acid. Although there is no limitation, an organic ammonium molybdate is preferred.

Examples of the activator (cocatalyst) include alkylaluminum halides such as ethylaluminum dichloride and diethylaluminum chloride, and organoaluminum compounds such as alkoxyalkylaluminum halides and organotin compounds. As a preparation for the reaction injection molding, a reaction injection molding material mainly composed of a norbornene-based monomer, a metathesis catalyst and an activator is used as a B liquid comprising a norbornene-based monomer and a metathesis catalyst,
The liquid is divided into two stable liquids, ie, the liquid A composed of the norbornene-based monomer and the activator, and each liquid is placed in a separate tank. At the time of reaction injection molding, these two liquids are mixed in a mixing chamber, and then this mixed liquid is injected into a cavity 24 of a mold, bulk polymerization is performed, and the insert 2
To obtain a molded article integrated with the molded article.

During the reaction injection molding, the temperature of the mold 22 and the temperature of the insert 20 are preferably 10 to 150.
° C, more preferably 30 to 120 ° C, still more preferably 50 to 100 ° C. The mold clamping pressure between the mold 22 and the insert 20 is usually 0.1 to 100 kg /.
cm ² . The polymerization time may be appropriately selected, but is usually 30 seconds to 20 minutes after the completion of the injection of the reaction solution.

In the reaction injection molding using the mold 22 according to this embodiment, the projecting portion 20a of the insert 20 is positioned at a position where the projecting portion 20a, which is a part of the insert 20, is exposed to the outside of the mold 22. Since it comes into contact with the elastic member 28 and is sealed here, the undiluted reaction solution injected into the mold 22 does not easily leak from the inside of the mold 22. Therefore, a high-quality molded product in which the insert 20 is integrated can be molded with little burrs or the like. Moreover, in this embodiment, there is no need to replace the packing or the like every molding, the production yield is good, and molding can be performed at low cost.

Further, in the present embodiment, not only the mold 22 but also the temperature of the insert 20 inserted into the mold 22 can be controlled, so that the reaction at the portion in contact with the insert 20 proceeds well. Thus, the adhesion between the insert 20 and the resin is improved. Further, even after the mold 22 is closed, the temperature of the insert 20 can be controlled to be constant, so that a reaction injection molded product of constant quality can be always obtained.

For example, in the above embodiment, the insert 20
The projecting portion 20a (terminal) contacts the mold with the elastic member 28, but in the present invention, this portion is not necessarily constituted by the elastic member, but is formed integrally with the mold body 26. Can also. In the above-described embodiment,
Although the current flowing through the insert 20 is monitored and the power supplied to the insert 20 is adjusted using the variable voltage power supply 30, the present invention is not limited to this. For example, the voltage applied to the insert 20 is monitored and the
Thus, the power supplied to the insert 20 may be adjusted.

Hereinafter, the present invention will be described with reference to examples in which the present invention is further embodied, but the present invention is not limited to these examples. In the following Examples and Reference Examples, parts and percentages are by weight unless otherwise specified. Reference Example 1 A mold for forming a round bar having a diameter of 50 mm and a length of 500 mm was prepared. As an insert, a diameter of 40 mm × length of 50 mm
At both ends of a 0mm aluminum round bar, 10mm in diameter
An aluminum insert having a protruding portion with a length of 50 mm was prepared.

This insert was placed inside a mold, a reaction stock solution was injected into the cavity of the mold, and reaction injection molding was performed. At the time of reaction injection molding, a narbornene-based monomer composed of 90% of dicyclopentadiene (DCP) and 10% of an asymmetric cyclopentadiene trimer is placed in two containers, one of which is diethyl aluminum chloride (DEAC) based on the monomer. Was added to give a 40 molar concentration and a 48 molar concentration of 1,3-dichloro-2-propanol (dcPrOH) (Solution A). On the other hand, tri (tridecyl) ammonium molybdate per monomer is
The solution was added to a concentration of 0 mmol (solution B). These A liquid and B liquid were stored in A tank and B tank, respectively.

The temperature of the mold is set at 30 ° C. by flowing hot water through a temperature control pipe mounted inside the mold, and the same volumes of the solution A and the solution B are mixed in the cavity of the mold. And inject,
After about 5 minutes had elapsed, the reaction-injection molded body into which the insert was integrated was taken out of the mold. When the protruding portion of the insert was manually pulled from the molded body, the insert came off the molded body. The remaining resin was cut, and the portion in contact with the insert was observed. As a result, the compound solution remained unreacted.

Except for the method shown below, a molded article with an integrated insert was molded in the same manner as in the Reference Example. The insert was heated to 50 ° C. with warm air before placing the insert in the mold. Thereafter, the insert is placed in the mold, and a current of 100 volts is applied from the protruding portion of the insert, and while monitoring the current at that time, the resistance of the insert becomes 8.3Ω, that is, Electric power was supplied to the insert so that the temperature of the insert was maintained at 50 ° C., and reaction injection molding was performed in that state.

In the obtained molded body, the protruding portion of the insert was manually pulled from the molded body, but could not be pulled out. According to the reaction injection molding according to the present invention, not only the mold, but also the temperature of the insert inserted into the mold can be controlled, so that the reaction at the portion in contact with the insert proceeds well, and the insert And the resin have good adhesion. Further, even after the mold is closed, the temperature of the insert can be controlled to be constant, so that a reaction injection molded product of a constant quality can be always obtained.

Next, another embodiment of the present invention will be described. A conductive coil, for example, a ground coil for a magnetically levitated railway of an induction repulsion method needs to be laid over the entire track on which the levitating body travels, and an enormous number of objects are targeted. Therefore,
In the production of coils, it is required to ensure stable performance, increase mass production efficiency, and keep costs as low as possible.

However, in the prior art, in the pre-heat treatment at the time of the integral molding, it is difficult to control the temperature of the metal part to be pre-heated, which causes not only a variation in molding quality but also a movement from the pre-heating equipment to the molding equipment. However, there is also a problem in terms of coil mass production efficiency. In this embodiment, a method of forming a conductive coil which stabilizes forming quality and is excellent in mass production efficiency by preheating such a ground coil for a magnetically levitated railway will be described.

FIG. 4 is a schematic structural view of a conductive coil preheating apparatus showing another embodiment of the present invention. Here, 101 is a molding die, 102 is a conductor coil, 103 is a coil lead terminal, 104 is an external power supply (power supply for power supply), 105 is a voltmeter, and 106 is a power supply cable (power supply wire).
In this embodiment, heat is directly and uniformly supplied from the external power supply (power supply for energization) 104 to the conductor coil 102 without using any special heating equipment.

Further, according to the method for preheating the conductive coil, a resistance method utilizing the property that the electric resistance of the conductor is proportional to its temperature, that is, according to the following equations (1) and (2), Lead terminal 10 of conductor coil 102
By flowing a constant current (I _s ) from 3 and measuring the voltage (V _c ) across the terminals with the voltmeter 105, the conductor coil 102 can be preheat-managed to the target temperature (t).

R _t / R _T = (1 + αt) / (1 + αT) (1) t = (1 / α) · (R _t / _RT ) · (1 + αT) −1 = (1 / α) · (1) / R _T ) · (V _C / I _s ) · (1 + αT) −1 (2) where R _t is a resistance value at t degrees K, and R _T is T
The resistance value α at the degree K is a temperature coefficient of resistance depending on the conductor material.

According to the conductive coil preheating method of this embodiment, an external power supply (power supply for power supply) 104 is connected to the lead terminal 103 of the conductor coil 102 via a power supply cable 106. Pre-heat treatment can be performed with the conductor coil 102 set in the molding die 101. As described above, according to the conductive coil preheating apparatus shown in FIG. 4, the conductive coil 102 integrally molded with the molding resin is preheated, and the coil output terminal 103 of the conductive coil 102 Electric wire 1
It is configured such that an energizing power supply 104 can be connected from the outside via an external power supply 06.

The energizing current may be DC or AC. In addition, by energizing the coil lead-out terminal 103 of the conductor coil 102 from an external power supply 104 via an electric wire 106, the conductor coil 1
02 is the same, but the conductor coil 10
The voltage at both ends of the coil lead terminal 103 is measured and managed by the voltmeter 105 when the power is supplied to the terminal 2 to control the preheating temperature of the conductor coil.

Table 1 shows that a DC current was applied to the coil before molding with respect to the ground coil for a magnetically levitated railway, and that the lead terminal at the time when the temperature of the thermocouple previously attached to the coil reached 60 ° C. shows the result of measuring the voltage across V _c.

[0049]

[Table 1]

From the measurement results, it is possible to control the temperature of the wound coil by energization within a range of about ± 5% even in consideration of the manufacturing error of the wound coil. It was confirmed that it had sufficient accuracy. It should be noted that the present invention is not limited to the above embodiment, and various modifications are possible based on the gist of the present invention.
They are not excluded from the scope of the present invention.

[0051]

As described above, according to the present invention, the following effects can be obtained. (A) According to the reaction injection molding of the present invention, not only the mold but also the temperature of the insert inserted into the mold can be controlled, so that the reaction at the portion in contact with the insert proceeds well. Thus, the adhesion between the insert and the resin is improved. Further, even after the mold is closed, the temperature of the insert can be controlled to be constant, so that a reaction injection molded product of a constant quality can be always obtained.

(B) Compared with conventional conductive coil heating equipment, preheating can be performed simply and in a short time. (C) An appropriate preheating temperature can be ensured with high accuracy only by controlling the voltage at both ends during energization. (D) Since energization heating is possible in a state of being set in a molding die, compared to the conventional heating method, temperature control during resin injection is easier, and molding quality can be stabilized.

(E) Since there is no movement of the conductive coil from the preheating equipment to the molding equipment, the mass production efficiency is good and the molding cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an apparatus used for reaction injection molding according to an embodiment of the present invention.

FIG. 2 is a perspective view of the insert shown in FIG.

FIG. 3 is a perspective embodiment of the mold shown in FIG. 1;

FIG. 4 is a schematic configuration diagram of a conductive coil preheating apparatus showing another embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 20 insert body 20a projecting portion 20b insertion body 22 mold 24 cavity 25 split surface 26 mold body 27 notch 28 elastic member 29 groove 30 variable voltage power supply 32 ammeter 34 wiring 36 control means 101 molding mold 102 conductor coil 103 Coil outlet terminal 104 External power supply (power supply for power supply) 105 Voltmeter 106 Cable for power supply (wire for power supply)

Continuing on the front page (72) Inventor Masao Torii 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Within Zeon Corporation (72) Inventor Katsuo Suzuki 1-1-2 Yakko, Kawasaki-ku, Kawasaki-shi, Kanagawa Nippon Zeon Inside the General Development Center Co., Ltd.

Claims (3)

[Claims] 1. An insert which can be energized from the outside is disposed inside a mold, a current is applied to the insert from the outside of the mold, and a resistance change due to a temperature change of the insert is detected. A reaction injection molding method, characterized in that the power supplied to the insert is changed according to the resistance change, and the reaction injection molding is performed in the mold while controlling the temperature of the insert. 2. The reaction injection molding method according to claim 1, wherein the insert is a conductive coil. 3. The reaction injection molding method according to claim 2, wherein the conductive coil is an induction repulsion type magnetically levitated ground coil for a railway.