JPH1199526A - Apparatus and method for manufacture of bucket shaped cast polyamide resin molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mold a cast polyamide resin molding of a box shape like a comparatively thin thickness bucket free from inner defects by a method wherein a lock of a top force is opened within a specific time from a point of tithe when a load loaded on the top force is equalized to a dead weight of the top force itself, and dropped to progress polymerization under pressure. SOLUTION: A bottom force 15 in which polymerizable lactam liquid is casted, is raised to fit a top force 1, and the polymerizable lactam liquid is polymerized. At that time the top force 1 is firstly fixed to an upper support base under a state of being immersed in the polymerizable lactam liquid, and a load loaded on the top force 1 becomes less than a dead weight of the top force 1 by buoyancy. As polymerization proceeds, force attracting the top force is generated by polymerization shrinkage and crystallization shrinkage of the polymerizable lactam liquid, the load loaded on the top force 1 rises, and suddenly risen by exceeding the dead weight of the top force 1. In the case where its load satisfies a specific range, a solenoid valve of a lock control means is functioned to make the top force drop downward by the dead weight, and a pressurized state is formed to progress polymerization further.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for producing a cast-shaped bucket-shaped polyamide resin molded article, and more particularly to a box-shaped cast polyamide resin molded article having a relatively small thickness without internal defects. The present invention relates to an apparatus and a method for manufacturing a body.

[0002]

2. Description of the Related Art In a method for producing a cast polyamide molded article, a mold is heated to a predetermined temperature in a hot blast furnace, the mold is taken out of the furnace, and a polymerizable lactam liquid is poured into the mold. The mold is placed in a hot air stove again to polymerize the lactam. However, according to this method, there is a drawback that the molded body tends to contain bubbles in the polymerization process. Usually, when an anionic polymerization of a polymerizable lactam liquid is performed, a volume shrinkage of about 15% occurs. This volume shrinkage has been one of the causes of generating cavity defects inside the compact. In a conventional method for producing a cast polyamide molded article, it has been a technically important task to reduce the occurrence of the above-described internal defects.

[0003] In order to prevent the occurrence of such internal defects in a molded article, a method of polymerizing a polymerizable lactam solution under pressure has been conventionally known. For example, Japanese Patent Publication No. 40-1615
As disclosed in Japanese Unexamined Patent Publication No. 3, there is a method in which the polymerizable lactam liquid is subjected to pressure molding when the viscosity of the system is increased to a maximum by polymerization.

Further, Japanese Patent Publication No. 39-25202 discloses that a mold maintained at a temperature at which polymerization proceeds and an auxiliary container maintained at a temperature at which polymerization does not proceed is insulated.
A method is disclosed in which a polymerizable lactam liquid is sealed in the auxiliary container and is pressurized with an inert gas so that the polymerizable lactam liquid is constantly fed into a mold to press-mold a polyamide molded article.

[0005]

However, in a method of manufacturing a molded article such as a bucket having a relatively small thickness,
When the polymerizable lactam liquid cast between the outer mold and the inner mold is constantly pressurized during polymerization, the height of the liquid fluctuates due to the movement of the inner mold at the beginning of polymerization, so that a bucket with good thickness accuracy is manufactured. It was practically difficult. For this reason, conventionally, after fitting the upper mold to the lower mold containing the polymerizable lactam liquid and fixing it, the polymerizable lactam liquid is polymerized, and after a certain period of time, the operator releases the lock of the upper mold. The polymerization was promoted under pressure by dropping the upper mold, but the timing of pressurization was greatly dependent on the blending system.

In addition, when polymerization is performed in an oven, the mold is taken in and out of the oven during casting, so that it is very difficult to control the temperature of the mold and the oven.

The present invention has been made to solve such a problem, and it has been found that the pressurizing time can be accurately controlled by the load applied to the upper mold without depending on the compounding system. Accordingly, it is an object of the present invention to provide a manufacturing apparatus and a manufacturing method for a box-shaped cast polyamide resin molded article such as a bucket having a relatively small thickness without internal defects.

[0008]

That is, the invention according to claim 1 of the present application provides a polymerizable lactam solution obtained by adding at least an anionic polymerization catalyst and an anionic polymerization initiator to substantially anhydrous ω-lactam in a mold. After casting, in an apparatus for producing a bucket-shaped cast polyamide resin molded article by anionic polymerization, a lower support base on which a lower mold that can be heated by a circulating heat medium is installed, and an upper mold that can be heated by a circulating heat medium An upper support pedestal arranged to measure the load applied thereto, elevating means provided on at least one of the upper and lower support pedestals so that the upper die and the lower die can be fitted to each other, and an upper support for the upper die A lock mechanism that is fixed to the base or opened to drop it, and a lock control means that activates the lock mechanism when the measured load value applied to the upper die exceeds a predetermined value. If, in the manufacturing apparatus of the bucket-shaped casting a polyamide resin molded product having a.

In this apparatus, the upper die is arranged on the upper support so that the load applied to the upper die can be measured, and the upper die is set within a predetermined time from the time when the load applied to the upper die becomes equal to its own weight. Since the lock can be released and dropped to allow the polymerization to proceed under pressure, even if the composition of the polymerizable lactam liquid changes, the load value applied to the upper mold is automatically and accurately measured and applied. Pressure can be started, and a box-shaped cast polyamide resin molded article such as a relatively thin bucket having no internal defects can be molded.

The invention according to claim 2 of the present application is directed to an apparatus for manufacturing a bucket-shaped cast polyamide resin molded body in which the elevating means is provided only on the lower support of the upper and lower supports, and is directed toward the fixed upper mold. Since the lower die is moved, the upper die and the lower die can be reliably and accurately fitted to each other.

According to the invention of claim 3 of the present application, the heat medium chambers provided in the upper mold and the lower mold are provided with at least one partition plate for forming a flow path of the heat medium. By preventing the stagnation, the temperature of the upper mold and the lower mold can be more uniformly adjusted.

According to a fourth aspect of the present invention, there is provided an apparatus for manufacturing a bucket-shaped cast polyamide resin molded body comprising a cylinder having a lock mechanism for controlling the movement of the upper die, and a pressure medium is introduced into or discharged from the cylinder apparatus. By doing so, reliable locking becomes possible.

[0013] The invention according to claim 5 of the present application is a method in which a polymerizable lactam solution obtained by adding at least an anionic polymerization catalyst and an anionic polymerization initiator to a substantially anhydrous ω-lactam is cast into a mold and then anionically polymerized. In the method for producing a bucket-shaped cast polyamide resin molded body by that, a lower support base mounted with a lower mold that can be heated by a circulating heat medium,
The upper mold that can be heated by the circulating heat medium is arranged in an opposed state with the upper support base installed so that the load applied to the upper mold can be measured, and at least the lower mold and the upper mold containing the polymerizable lactam liquid are arranged. One side is moved, and the upper mold is fitted with the upper mold floating on the polymerizable lactam liquid, and the load W applied to the upper mold fixed to the upper support base is A, the weight of the upper mold itself is A, and the upper mold is polymerizable. Assuming that the buoyancy when floated on the lactam liquid is F, if the following formula (A-0.5F) ≦ W ≦ (A + 2.5F) is satisfied, release the lock of the upper die and drop it. The present invention is directed to a method for producing a bucket-shaped cast polyamide resin molded article, in which the polymerization is advanced under pressure, and after the polymerization is completed, the upper mold and the lower mold are separated and the molded article is released.

In this method, the upper mold is placed on the upper support so that the load applied to the upper mold can be measured, and the load W applied to the upper mold is A, the weight of the upper mold itself, and the upper mold is the polymerizable lactam liquid. When the buoyancy when floated is F, (A-0.5
When the range of F) to (A + 2.5F) is satisfied, the lock of the upper mold is released and dropped, and the polymerization is allowed to proceed under pressure. Can be automatically and accurately measured to start pressurization, and a box-shaped cast polyamide resin molded article such as a relatively thin bucket having no internal defects can be formed.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a front view of an apparatus for producing a bucket-shaped cast polyamide resin molded article according to the present invention, FIG. 2 is a side view of FIG. 1, and FIG. 3 is a schematic view of an air circuit.
According to this, FIG. 1 shows a state where the upper mold 1 and the lower mold 15 are respectively installed at predetermined positions of the manufacturing apparatus 40. In this manufacturing apparatus 40, four guide rods 42 are placed on a base 51.
Are fixed in an upright state, the lower support base 41 on which the lower mold 15 is installed and fixed is fitted into these four guide rods 42, and is moved up and down by a lifting / lowering means 43 installed at the center of the lower surface of the lower support base 41. I do. The lifting / lowering means 43 rotates the ball screw 46 supported by the substrate 45 by driving the motor 44 to reciprocate the lower mold 15 in the vertical direction. The upper limit can be stopped by a limit switch. The polymerizable lactam liquid is cast at the lowermost position of the lower mold 15.

On the other hand, the upper die 1 is provided with the four guide rods 42 described above.
Is mounted via a lock mechanism 60 on an upper support base 48 fixed to the end of the base. The lock mechanism 60 has a function of fixing the upper die 1 to the upper support base 48 or moving the upper die 1 to release the upper die 1. The air cylinder 49 mounted at the center of the upper support base 48, 49 rods 5
A connecting plate 52 with a guide 51 directly connected to the connecting plate 52, a pair of load cells 53 fixed to the connecting plate 52, and a movable plate 54 fixed to the load cell 53, and the movable plate 54 is connected via four connecting rods 55. The upper mold 1 is stably suspended. Therefore, when the lock mechanism 60 is operated to fix the upper die 1 to the upper support base 48, the load applied to the upper die 1 is measured by the load cell 53.

The lock control means 61 for operating the lock mechanism 60 sends compressed air to the rooms A and B in the air cylinder 49, adjusts the internal pressure of each room, holds the position of the piston 62, and moves the upper die 1 The upper mold 1 is dropped by its own weight by fixing and releasing the internal pressure of the room B by operating the solenoid valve 63. The solenoid valve 63 is connected to the load cell 53.
Is activated when a predetermined value is reached. Further, a check valve 64 is provided in the circuit connected to the room B.

FIG. 4 is a plan view of the upper mold set in the apparatus for manufacturing a bucket-shaped cast polyamide resin molded article of the present invention, FIG. 5 is a sectional view taken along line AA of FIG. 4, and FIG. FIG. 7 is a plan view of a lower mold set in the apparatus for manufacturing a mold polyamide resin molded body, and FIG. 7 is a cross-sectional view taken along the line BB of FIG.

The upper die 1 includes a main body 2 made of aluminum, iron or the like having a relatively high thermal conductivity, and a molded portion 3 projecting outward from the main body 2.
A closed heat medium chamber 5 in which a heat medium such as oil flows by fixing the upper plate 4 to the main body 2 with screws or the like is provided inside the molded portion 3. The heat medium chamber 5 is provided with a partition plate 6 therein to improve the flow of the heat medium. In the embodiment, the heat medium chamber 5 is divided into four chambers 7 by a cross plate 6 provided in a cross shape, and is discharged from the inlet 8. The heat medium is circulated to the outlet 9 by a pump (not shown) to accurately control the temperature.

When measuring the temperature of the upper mold 1, the upper mold 1
Is measured by contacting the surface thermometer with the surface of the upper mold 1 before fitting the lower mold 15 into the lower mold 15.

The lower mold 15 has a recessed accommodation portion 17 into which the protruding molded portion 3 of the upper mold 1 is fitted, and a closed heat medium chamber 18 through which a heat medium flows is formed by an outer wall 19 outside. . A heat insulating material (not shown) is attached to the outer wall 19. A partition plate 20 is also provided in the heat medium chamber 18, and the heat medium flowing from the inlet 21 flows smoothly without stagnation, flows out of the outlet 22, and circulates again to flow to the inlet 21. It has become.

As shown in FIG. 7, a temperature sensor 24 is attached to the outer wall of the housing 17 in order to accurately control the temperature of the lower mold 15. The temperature sensor 24 is housed in a shielding room 25 so as not to directly touch the heat medium. Two or more temperature sensors 24 can be provided.

FIG. 8 shows a lower mold 1 cast with a polymerizable lactam liquid.
5 shows a state in which the lifting / lowering means 44 is operated to move up along the guide rod 42 and fitted to the upper mold 1 to polymerize the polymerizable lactam liquid. At this time, the upper mold 1 is initially fixed to the upper support base 48 and is in a state of being immersed in the polymerizable lactam liquid, and the load W applied to the upper mold 1 becomes smaller than the own weight A of the upper mold 1 due to the buoyancy F. I have. When the polymerization proceeds, a force for attracting the upper mold is generated due to polymerization shrinkage and crystallization shrinkage of the polymerizable lactam liquid, and the load W applied to the upper mold 1 increases, and rapidly increases beyond the own weight A of the upper mold 1. I do. The load W applied to the upper mold 1 is (A-0.5F) to (A + 2.5
When the range of F) is satisfied, the solenoid valve 63 of the lock control means 61 is operated to release the internal pressure of the room B, thereby dropping the upper mold 1 downward by its own weight, and further pressurizing to carry out polymerization. Let go.

FIG. 9 shows the upper mold 1 and the lower mold 1 even after the polymerization is completed.
5 shows a state in which the temperature of the heat medium passing through the inside 5 is kept constant, the lower mold 15 is lowered, and the superimposed bucket-shaped molded body 30 is removed from the upper mold 1. In this case, the molded body 30 contracts and separates from the lower mold 15 and adheres to the upper mold 15.

The method for producing the bucket-shaped cast polyamide resin molded article according to the present invention will be described below in detail. First, the ω-lactam is dehydrated in a dehydration tank under reduced pressure to make it substantially anhydrous, and then replaced with an inert gas such as nitrogen. The ω-lactam in the dehydration tank is
Weighed into two casting tanks, then a given amount of anionic polymerization catalyst is placed in one casting tank containing ω-lactam, and a given amount of anionic polymerization initiator is placed in the other, containing ω-lactam. It is put into the casting tank. And
The upper mold 1 and the lower mold 15 for forming the bucket are set on the upper support 48 and the lower support 41 of the manufacturing apparatus 40.

The polymerizable lactam solution discharged from each casting tank and mixed and stirred in the mixing section is heated at 150 to 170 ° C.
After the lower mold 15 is cast into the lower mold 15 whose temperature has been adjusted, the lower mold 15 is raised by the operation of the motor 44 and fitted with the upper mold 1 whose temperature has been adjusted to 143 to 167 ° C. A cavity 32 is formed therebetween. As shown in FIG. 8, a gap 33 of about 2 to 8 mm is provided between the lower die 15 and the upper die 1 in this state. The gap 33 can be freely adjusted by a motor 44 and a limit switch.

The upper mold 1 is initially fixed to the upper support base 48 and is immersed in a polymerizable lactam liquid. The load applied to the upper mold 1 is smaller than the weight of the upper mold 1 due to buoyancy. At this time, the temperature of the upper mold 1 and the lower mold 15 is such that the temperature of the upper mold 1 is substantially the same as the temperature of the lower mold 15, or the temperature of the upper mold 1 is lower than that of the lower mold 15, preferably 3 to 6 °. C
The degree may be varied.

Thereafter, the polymerization proceeds, and a force for attracting the upper mold is generated due to polymerization shrinkage and crystallization shrinkage.
The load imposed on the vehicle rapidly rises above its own weight. When the load W applied to the upper mold 1 satisfies (A-0.5F) to (A + 2.5F), the solenoid valve 63 of the lock control means 61 is operated to release the internal pressure of the room B, so that the upper mold is released. 1 is dropped by its own weight, and the polymerization is further progressed under a pressurized state. At this time, since the molded body 30 is pressurized by the upper mold 1, crystallization further proceeds, and even if the volume of the molded body 30 is gradually shrunk, the molded body 30 has a uniform thickness without voids therein. The body 30 can be finished.

However, when the load W applied to the upper mold 1 is (A)
When the polymerizable lactam liquid is dropped and pressurized before reaching −0.5 F), the viscosity of the polymerizable lactam liquid does not sufficiently increase at the initial stage of polymerization, and the polymerizable lactam liquid flows to reduce the thickness of the molded article. On the other hand, (A + 2.
If the pressure exceeds 5F), the crystallization of the polymerizable lactam solution proceeds and the volume shrinks greatly in a state where the timing of pressurization is shifted and the pressurization is not performed. Not only does it occur, but recesses tend to occur on the appearance of the molded article.

Even if the polymerization is completed, the temperature of the upper mold 1 and the lower mold 1
The temperature of the heat medium flowing in the inside 5 is kept constant, and the lower mold 15 is lowered to take out the superimposed bucket-shaped molded body 30 from the upper mold 1. At this time, the lower mold 15 is cleaned.

The ω-lactam used in the present invention is substantially anhydrous α-piperidone, ε-caprolactam, ω-lactam.
Laurolactam, ω-enantholactam, ω-caprylactam, ω-laurolactam, ω-decanolactam,
ω-Undecanolactam, etc. or a mixture of two or more thereof, and industrially advantageous lactams are ε-caprolactam and ω-laurolactam.

The anionic polymerization catalyst used in the present invention may be sodium hydride, lithium hydride, sodium,
Known polymerization catalysts for ω-lactams such as potassium can be used, and the amount added is 0.1 to ω-lactam.
~ 2.0 mol%. Examples of the anionic polymerization initiator include N-acetyl-ε-caprolactam, isocyanate, diisocyanate, urea derivative, urethane, and isocyanurate derivative.
The range of 0.05 to 1.0 mol% with respect to the lactam is preferred.

In the above production method, the anionic polymerization catalyst
A method of adding and mixing an anionic polymerization initiator after or after adding and dissolving to a lactam, or a method of casting an ω-lactam containing an anionic polymerization catalyst and an ω-lactam containing an anionic polymerization initiator. Alternatively, it is adjusted by a method of adding and mixing after casting. Further, the polymerization of ω-lactam can be carried out at a temperature of 100 to 210 ° C., preferably 130 to 180 ° C.

In carrying out the method of the present invention, other than the above components, lubricants such as oils, waxes, zinc stearate, calcium stearate and the like, which do not inhibit polymerization, and reinforcing materials such as carbon fiber and wollastonite may be added. It is possible.

[0035]

The present invention will be described in more detail with reference to the following examples. Examples 1 to 3 After dehydration, ε-caprolactam in the dehydration tank was weighed and put into two casting tanks, and 1,250 g was put into one casting tank and 1,250 g was put into the other casting tank. Thereafter, a predetermined amount of sodium hydride (63% oil) was added and dissolved in one casting tank, and a predetermined amount of triphenylisocyanurate was further added to the other casting tank. During this time, the polymerizable lactam solution was mixed while the temperature was raised to 125 ° C. while flowing nitrogen in the casting tank under atmospheric pressure.

The upper and lower dies made of iron (length 200 mm, width 30
(5 mm, depth 160 mm) was set in the molding machine, and the temperature of the oil in the upper mold and the oil in the lower mold were set to 167 ° C. and 169 ° C., respectively, and the mold was heated. The temperature of the upper mold was measured with a surface thermometer, and the temperature of the lower mold was measured with a temperature sensor attached to the outer wall. Then, after pouring the mixed polymerizable lactam liquid into the lower mold, the lower mold is raised and fitted to the upper mold heated to a predetermined temperature, and a gap of about 8 mm is provided between the upper mold and the lower mold. The polymerization was carried out in the state. At this time, the upper mold is fixed to the upper support.

As shown in FIG. 10, the load applied to the upper mold 1 is smaller than its own weight due to buoyancy immediately after the upper mold is fitted to the lower mold. The result shows that it rises sharply beyond its own weight. Also,
At the same time, the temperature of the lower mold measured by two temperature sensors attached to the lower mold is also shown. FIGS. 11 and 12 show the case where the catalyst and the initiator are increased. However, since the polymerization proceeds quickly, the time required for the load applied to the upper mold 1 to exceed its own weight and start to increase is short.

In any case, at the point A where the load applied to the upper mold 1 has reached its own weight, the solenoid valve 63 of the lock control means 61 is operated to release the internal pressure of the room B, so that the upper mold 1 is released. The polymer was dropped downward by its own weight, and was pressurized to further advance the polymerization. When the polymerization was completed, the lower mold was lowered, and a 6 mm-thick bucket molded body was taken out.

After the molded body was sufficiently cooled, the results of observing the inside with naked eyes and observing cavity defects are shown in Table 1.

[0040]

[Table 1]

As a result, as the amount of the catalyst and the initiator increases, the time required for the load applied to the upper mold 1 to reach its own weight is shortened. In each case, a bucket having a relatively thin thickness having no internal defects is used. I got it.

Examples 4 to 7 and Comparative Examples 1 and 2 A 6 mm-thick bucket compact was produced in the same manner as in Example 1, but in this example, the load W applied to the upper mold reached a predetermined load. Sometimes the upper mold 1 was dropped. Table 2 shows the results of observing the cavity defects of the obtained compact.

[0043]

[Table 2]

As a result, the load W applied to the upper mold is (A−
0.5F) to (A + 2.5F) (however, if the weight of the upper mold itself is in the range of A, and the buoyancy when the upper mold is floated on the polymerizable lactam liquid is F), pressurization in the range of Although a relatively thin bucket was obtained, an internal defect occurred outside this range.

[0045]

As described above, in the invention according to claim 1 of the present application, the lower support base on which the lower mold that can be heated by the circulating heat medium is installed and the upper mold that can be heated by the circulating heat medium are related to this. An upper support placed so as to be able to measure the load, lifting means provided on at least one of the upper and lower supports so that the upper mold and the lower mold can be fitted together, and the upper mold with respect to the upper support. A bucket-shaped casting system comprising: a lock mechanism that is fixed or released to drop the same; and a lock control unit that activates the lock mechanism when a measured load value applied to the upper mold exceeds a predetermined value. In the apparatus for manufacturing a polyamide resin molded body, the upper mold is disposed on the upper support so that the load applied thereto can be measured, and when the load applied to the upper mold is within a predetermined range, the lock of the upper mold is released. Move and pressurize Because the polymerization can proceed, even if the composition of the polymerizable lactam liquid changes, the load value applied to the upper mold can be automatically and accurately measured to start pressurization, and a relatively thick film with no internal defects There is an effect that a box-shaped cast polyamide resin molded article such as a thin bucket can be molded.

In the invention according to claim 2 of the present application, since the elevating means is provided only on the lower support of the upper and lower supports,
Since the lower die is moved toward the fixed upper die, there is an effect that the upper die and the lower die can be securely and accurately fitted at an accurate position.

According to the invention of claim 3 of the present application, the heat medium chambers provided in the upper mold and the lower mold are provided with at least one partition plate for forming a flow path of the heat medium. By preventing the stagnation, the temperature of the upper mold and the lower mold can be further adjusted.

In the invention according to claim 4 of the present application, the lock mechanism for controlling the movement of the upper die is constituted by a cylinder device, and the locking can be reliably performed by inserting and discharging the pressure medium into and from the cylinder device. .

[0049] The invention according to claim 5 of the present application is designed to measure the load applied to a lower support on which a lower mold that can be heated by a circulating heat medium is installed and an upper mold that can be heated by a circulating heat medium. The upper support placed in the opposite direction is arranged, and at least one of the lower mold and the upper mold containing the polymerizable lactam liquid is moved, and the upper mold is fitted with the polymer lactam liquid floating. When the load W applied to the upper mold fixed to the upper support base is A, the weight of the upper mold itself is A, and the buoyancy when the upper mold is floated on the polymerizable lactam liquid is F, (A
When −0.5F) ≦ W ≦ (A + 2.5F) is satisfied, the lock of the upper mold is released and dropped, and the polymerization is allowed to proceed under pressure. Separating the mold and removing the molded body, there is a method of manufacturing a bucket-shaped cast polyamide resin molded body, in this method, the upper mold is disposed on the upper support so that the load applied to it can be measured,
When the load on the upper mold is within the specified range, the lock on the upper mold is released and dropped, and the polymerization proceeds under pressure, so even if the composition of the polymerizable lactam liquid changes, the load on the upper mold Pressurization can be started by automatically and accurately measuring the value, and a box-like cast polyamide resin molded article such as a relatively thin bucket having no internal defects can be formed.

[Brief description of the drawings]

FIG. 1 is a front view of an apparatus for producing a bucket-shaped cast polyamide resin molded article of the present invention.

FIG. 2 is a side view of FIG.

FIG. 3 is a schematic diagram of an air circuit.

FIG. 4 is a plan view of an upper mold used in the method for producing a bucket-shaped cast polyamide resin molded article of the present invention.

FIG. 5 is a sectional view taken along line AA of FIG. 4;

FIG. 6 is a plan view of a lower mold used in the method for producing a bucket-shaped cast polyamide resin molded article of the present invention.

FIG. 7 is a sectional view taken along the line BB of FIG. 6;

FIG. 8 is a cross-sectional view showing a state where the lower mold and the upper mold are fitted to each other with a gap provided between them.

FIG. 9 is a side view of FIG. 1 showing a state in which the lower die is lowered to take out a molded body.

FIG. 10 is a graph showing the relationship between the polymerization time during polymerization and the load applied to the upper mold, and the relationship between the polymerization time and the lower mold temperature.

FIG. 11 is a graph showing the relationship between the polymerization time during polymerization and the load applied to the upper mold, and the relationship between the polymerization time and the lower mold temperature.

FIG. 12 is a graph showing the relationship between the polymerization time during polymerization and the load applied to the upper mold, and the relationship between the polymerization time and the lower mold temperature.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper mold 15 Lower mold 17 Housing part 18 Heat medium room 19 Outer wall 20 Partition plate 21 Inlet 22 Outlet 30 Molded body 40 Molding machine 41 Lower support 42 Guide rod 43 Elevating device 44 Motor 48 Upper support 49 Air cylinder 52 Connecting plate 53 Load cell 54 Movable plate 55 Connecting rod 60 Lock mechanism 61 Lock control means 63 Solenoid valve

Claims (5)

[Claims] 1. A bucket-shaped cast polyamide resin obtained by casting a polymerizable lactam liquid obtained by adding at least an anionic polymerization catalyst and an anionic polymerization initiator to substantially anhydrous ω-lactam, and then performing anion polymerization. In a device for manufacturing a molded body, a lower support base on which a lower mold that can be heated by a circulating heat medium is installed, and an upper support table that is arranged with an upper mold that can be heated by a circulating heat medium so that a load applied thereto can be measured. Lifting means provided on at least one of the upper and lower supports so that the upper mold and the lower mold can be fitted to each other; and fixing the upper mold to the upper support or opening and lowering the upper mold. And a lock control means for activating the lock mechanism when a measured load value applied to the upper mold exceeds a predetermined value. Apparatus for producing an amide resin molding. 2. The apparatus according to claim 1, wherein the lifting means is provided only on the lower support of the upper and lower supports. 3. The bucket-shaped cast polyamide resin molded article according to claim 1, wherein at least one partition plate forming a flow path of the heat medium is provided in the heat medium chambers provided in the upper mold and the lower mold. Manufacturing equipment. 4. The apparatus according to claim 1, wherein the lock mechanism for controlling the movement of the upper mold comprises a cylinder. 5. A bucket-shaped cast polyamide resin obtained by casting a polymerizable lactam solution obtained by adding at least an anionic polymerization catalyst and an anionic polymerization initiator to substantially anhydrous ω-lactam, and then performing anion polymerization. In the method of manufacturing a molded body, a lower support base on which a lower mold that can be heated by a circulating heat medium is installed, and an upper support that is installed so that a load applied to the upper mold that can be heated by a circulating heat medium can be measured. Place the table opposite to each other, move at least one of the lower mold and the upper mold containing the polymerizable lactam liquid, fit it with the upper mold floating on the polymerizable lactam liquid, and fit it to the upper support base. When the load W applied to the fixed upper die is A, the weight of the upper die itself is F, and the buoyancy when the upper die is floated on the polymerizable lactam liquid is F, the following formula (A-0.5F) ≦ W ≦ (A + 2.5 ) If the condition is satisfied, release the lock of the upper mold, drop it, allow the polymerization to proceed under pressure, and after the polymerization is completed, separate the upper mold and the lower mold and remove the molded body. A method for producing a bucket-shaped cast polyamide resin article, characterized in that: