JP2828161B2 - Plastic molding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic molding apparatus applied to plastics, mirrors, prisms and applied products thereof, and more particularly to a plastic molding apparatus capable of molding plastic molded articles with high precision and in a short time. Related to the device.

[0002]

2. Description of the Related Art Conventionally, at the time of molding a plastic molded product, a thermoplastic plastic base material pre-processed to a substantially final shape by injection molding is formed by molding at least one piece having the same shape and volume as the cavity of an injection mold. Insert into a mold with a cavity having a mirror surface, heat and melt the plastic matrix above its glass transition temperature, generate a resin internal pressure in the cavity, gradually cool and transfer the mirror surface by the resin internal pressure This is useful because it can reduce the internal pressure of resin generated at the time of heating to a fraction of the conventional value, so that multiple pieces such as 5 pieces or 10 pieces can be taken. (For example, refer to JP-A-4-366608 and JP-A-5-162139 as such conventional methods ).

[0003] For this reason, it is ideal to mount and mold the die on a press machine in view of miniaturization of the apparatus and stability of quality. For this reason, when the mold is mounted on a press machine and the mold is heated and cooled to form a plastic molded product as described above, heating can be easily performed by heating the mold with an electric heater or the like. For cooling, it is necessary to wait for natural cooling or to forcibly cool with air or water using a heat pipe or the like embedded in a mold. However, the former can cool the mold at a uniform temperature, but the natural cooling is performed, so that the cooling cycle is 1 ° C./min or less, so that the molding cycle becomes longer and the productivity is extremely poor. Although there is no problem at 1 to 6 ° C./min, a control device for that purpose, for example, a control device for blowing air to the heat pipe fin portion only at the time of cooling or for flowing water is required. The structure becomes complicated.

As a cooling structure for solving such a problem, there is a cooling structure described in Japanese Patent Application Laid-Open No. H5-124078. When the mold is cooled, the mold is inserted into a press machine, a temperature adjusting member laid on the press machine is brought into contact with the mold surface, and the heat of the mold is pressed during compression by the press machine. Cooled to the machine side.

[0005]

However, in such a conventional molding apparatus for plastic molded articles,
Because the mold was inserted into the press only during cooling, the mold and the press were separate, so a mechanism was needed to transfer the mold to the press.
Together with Mau, quality of molded products for cooling the mold with separate pressing machine has a problem of unstable. Therefore, the present invention provides a method for quickly heating a mold and a press machine even if a mold and a press machine (mold clamping and mold opening devices) are integrated.
The molding can be performed quickly and uniformly within a range that does not cause a problem on the internal distortion of the molded product or the mirror surface transferability, so that the molded product can be molded in a short molding cycle. An object of the present invention is to provide a plastic molding apparatus capable of stabilizing the quality of a molded product.

[0006]

According to the first aspect of the present invention,
In order to solve the above-mentioned problem, a thermoplastic base material pre-processed to a substantially final shape by injection molding is made to have at least one shape and volume equal to the cavity of the injection mold.
Into a mold having a cavity with two mirror surfaces, and heat the plastic matrix above its glass transition temperature.
In a molding apparatus of a plastic molded product that melts to generate a resin internal pressure in the cavity, gradually cools and transfers a mirror surface by the resin internal pressure , a heating plate, a heat insulating plate, and a cooling plate are provided in the mold, and the heating is performed. It is characterized in that the plate, the heat insulating plate and the cooling plate are closed and the die is integrally mounted on the opening device.

According to a second aspect of the present invention, in order to solve the above-mentioned problem, in the first aspect of the present invention, a heating plate, a heat insulating plate, and a cooling plate are arranged in the mold opening direction of the mold in this order. And According to a third aspect of the present invention, in order to solve the above-mentioned problems, in the second aspect of the present invention, the heating rate during heating is 10 ° C./min or more, and the cooling rate during cooling is 1 ° C./min or more. The material and thickness of the mold, the heating plate, and the heat insulating plate are selected so as to satisfy the following conditions. According to a fourth aspect of the present invention, in order to solve the above problem, in the second aspect of the present invention, the thickness of the heating plate is 10 to 50 mm.

According to a fifth aspect of the present invention, in order to solve the above-mentioned problem, in the second aspect of the present invention, the thickness of the heat insulating plate is 1 to 30 mm. According to a sixth aspect of the present invention, in order to solve the above-mentioned problem, in the second aspect of the present invention, the heat conductivity of the mold and the heating plate is 0.05 cal · cm ⁻¹ · S ⁻¹ · ° C. ^−1. It is characterized by the above. According to a seventh aspect of the present invention, in order to solve the above-mentioned problem, in the second aspect of the invention, the thermal conductivity of the heat insulating plate is 0.001 to 0.05 cal · cm.
It is characterized in that it is a ^-1 · S ^-1 · ℃ ^-1.

According to an eighth aspect of the present invention, in order to solve the above problem, in the second aspect of the present invention, the thermal conductivity of the cooling plate is 0.05 cal · cm ⁻¹ · S ⁻¹ · ° C. ^-1. As described above, the temperature is 10 to 100 ° C. According to a ninth aspect of the present invention, in order to solve the above-mentioned problem, in the second aspect of the present invention, the thermal conductivity, the ratio, the density, and the plate thickness of the heating plate are respectively λ ₁ , C ₁ , ρ
₁ , t ₁ , that of the heat insulating plate is λ ₂ , C ₂ , ρ ₂ , t ₂ , and the temperature of the cooling plate is T ( K ),

[0010]

(Equation 2)

However, T _O : 273K, λ: (cal · cm ⁻¹⁾
· S ^-1 · ° C ^-1 ), C: (cal · g ^-1 · ° C ^-1 ), ρ: (g · c
m ⁻³ ), a heating plate, a heat insulating plate, and a cooling plate.

[0012]

[Action] In the first aspect of the present invention, the heating plate in the mold, the heat insulating plate, the cooling plate is provided, the heating plate, insulation plate, cooling plate mold closing, is integrally attached to the mold opening device. Therefore, even if the mold and mold clamping and mold opening devices are integrated,
With heating is rapidly performed, cooling is fast and uniform within a range not to internal strain and mirror transferability problems of a molded article
The molding is performed in a short molding cycle,
Furthermore, the size and die size of the device can be achieved, the quality of molded products can be stabilized.

That is, the point of view of the present invention is that the heating rate is preferably as high as possible, but the cooling rate cannot be too high due to the above-mentioned mirror transferability and internal distortion. In other words, if materials with different thermal conductivities are combined appropriately, heat is transferred preferentially to materials with good thermal conductivity during heating, and materials with poor thermal conductivity have poor responsiveness, so the temperature is still sufficiently raised. do not do. In the meantime, a certain amount of heat is supplied to the material of the cavity, and it becomes higher than the glass transition point. Next, since the cooling rate is not so fast, not only materials with good thermal conductivity,
Can respond to bad materials. Therefore, it has been found that if a material having good heat conductivity and a material having poor heat conductivity are properly combined, heating can be performed quickly and cooling can be performed uniformly and smoothly. That is, in addition to a mold, a heating plate, a heat insulating plate, and a cooling plate are provided.

According to the second aspect of the present invention, the heating plate, the heat insulating plate, and the cooling plate are arranged in this order in the mold opening direction. With such a configuration, at the time of heating, sudden heat generated from the heating plate is transmitted to a mold having good thermal conductivity, and the resin in the cavity becomes higher than its glass transition point. Next, after the temperature is controlled until the temperature reaches the glass transition point or more up to the center of the cavity, the heating is stopped. During this time, the temperature difference between the cooling plate and the heating plate becomes large, and heat moves in the heat insulating plate (although low thermal conductivity). Then, although slowly, heat in the heating plate and the mold moves to the cooling plate through the heat insulating plate. Since the cooling plate is controlled by a refrigerant such as air or hot water so as to be constantly at a constant temperature, heat transferred to the cooling plate is removed by the refrigerant. In this way, the temperature rises rapidly during heating and is cooled at a constant rate during cooling.

Therefore, heating is performed quickly without cooling control, and the cooling rate is also increased within a range that does not cause a problem in the internal distortion of the molded product or the mirror surface transferability. Molded,
With the miniaturization of the device and the miniaturization of the mold ,
The quality of molded products is stable. According to the third aspect of the present invention, the mold, the heating plate, and the heat insulating plate are so set as to satisfy the conditions that the heating rate during heating is 10 ° C./min or more and the cooling rate during cooling is 1 ° C./min or more. Since each material and plate thickness are selected, a rapid heating rate (10 ° C./min or more) and uniform and
One is a smooth cooling rate (1 ° C. / min or higher, 3 ° C. / min or less before and after the glass transition point, 6 ° C. in other cases
/ Min or less is preferable. ) Is possible. As a result,
The molding cycle of the molded article is shortened.

The heating rate during heating is 10 ° C./min.
The reason why the cooling rate during cooling is 1 ° C./min or more is that the heating rate is less than 10 ° C./min and the cooling rate is 1 ° C./min.
If it is less than min, the molding cycle becomes longer, and the productivity decreases. According to the fourth aspect of the present invention, since the thickness of the heating plate is set to 10 to 50 mm, the heating speed can be quickly increased, and the molding cycle of the molded product can be further shortened. When the thickness of the heating plate is set to 10 to 50 mm, if the thickness of the heating plate is less than 10 mm, the size of the electric heater or the like becomes small, resulting in insufficient heat supply. If the thickness of the heating plate exceeds 50 mm, the heat capacity of the heating plate increases. This is because the heating rate decreases unless the heat supply amount is increased.

According to the fifth aspect of the present invention, since the thickness of the heat insulating plate is set to 1 to 30 mm, the heating rate can be increased, and the cooling rate can be sufficiently obtained. The cycle can be further shortened. That is, to not be exhibited sufficiently heat insulating effect heating rate is lowered <br/> My upon heating the thickness of the heat insulating plate is less than 1 mm, although the heating is good exceeds 30 mm, a sufficient cooling rate during cooling No longer available. In the invention according to claim 6,
The thermal conductivity of the mold and the heating plate is 0.05 cal · cm ^-1 ·
Since the temperature is set to S ⁻¹ · ° C. ⁻¹ or more, the heating rate can be increased, and the molding cycle of the molded article can be further shortened. On the other hand, when the thermal conductivity of the mold and the heating plate is less than 0.05 cal · cm ⁻¹ · S ⁻¹ · ° C. ⁻¹ ,
Poor thermal conductivity results in insufficient heating of the cavity, resulting in a reduced heating rate.

In the invention according to claim 7, the thermal conductivity of the heat insulating plate is 0.001 to 0.05 cal · cm ^-1 · S ^-1 · ° C ^-1.
Because it is set to, it is possible to increase the heating rate, it is possible to obtain a sufficient cooling rate, the molding cycle of molded articles can be further shortened. On the other hand, the thermal conductivity of the heat insulating plate is 0.05 cal · cm ⁻¹
If the temperature exceeds S ⁻¹ · ° C. ⁻¹ , the heat insulating effect is reduced and the heating rate is reduced, and 0.001 cal · cm ⁻¹ · S ⁻¹ · ° C.
^If it is less than ^-1 , the cooling rate decreases, which is not preferable.

[0019] In the invention of claim 8 is the thermal conductivity of the cooling plate ^{0.05cal · cm -1 · S -1 ·} ℃ -1 or higher, because the temperature is set to 10 to 100 ° C., cooled The speed can be adjusted sufficiently. On the other hand, if the thermal conductivity of the cooling plate is less than this, the cooling part temperature control becomes insufficient, and if the temperature is within this range, it can be easily controlled by water cooling.

According to the ninth aspect of the present invention, the thermal conductivity, the ratio, the density, and the plate thickness of the heating plate are respectively λ ₁ , C ₁ , ρ
₁ , t ₁ , that of the heat insulating plate is λ ₂ , C ₂ , ρ ₂ , t ₂ , and the temperature of the cooling plate is T ( K ),

[0021]

(Equation 3)

It is composed of a heating plate, a heat insulating plate, and a cooling plate satisfying the following. Therefore, by setting the thermal conductivity, ratio, density, plate thickness, and cooling plate temperature of each material so as to apply to this formula, the heating rate is very fast and the cooling rate is also fast within a range that does not adversely affect the molded product. can do.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. 1 and 2 are views showing an embodiment of the plastic molding apparatus according to the first aspect of the present invention. First, the configuration will be described.
In FIG. 1, reference numeral 1 denotes an upper die, 2 denotes a lower die, and a cavity 3 having at least one mirror surface is defined on the opposing surfaces of the upper die 1 and the lower die 2. The cavity 3 is formed to have the same shape and volume as the cavity of the injection mold, and a thermoplastic base material pre-processed into a substantially final shape by injection molding is inserted. I have.

The upper heating plate 4, the lower heating plate 5, the lower heating plate 5, and the lower heating plate 5 are arranged in the respective mold opening directions (indicated by arrows).
An upper cooling plate 6, a lower cooling plate 7, an upper heat insulating plate 8, and a lower heat insulating plate 9 are attached, and each of these plates 4 to 9 is an upper die plate.
The die plates 10 and 11 are attached to the die 10 and the lower die plate 11, and these die plates 10 and 11 are configured to clamp and open the molds 1 and 2, thereby forming a mold clamping and mold opening device. Heating members such as electric heaters are provided in the upper and lower heating plates 4 and 5, and refrigerant such as oil, water, and air flows in the upper and lower cooling plates 6 and 7. Next, a method of forming a formed article by such a forming apparatus will be described. First, after heating the upper and lower molds 1 and 2 around the thermal deformation temperature of the resin, insert a blank (base material) having a substantially final shape equivalent to the volume of the cavity 3 into the cavity 3, After the molds 1 and 2 are closed by bringing the die plates 10 and 11 close to each other, the molds are clamped with a fixed mold clamping pressure, and the heating plates 4 and 5 are heated by an electric heater to remove the molds 1 and 2 from each other. Heat above the glass transition point of the resin.

Therefore, the internal distortion of the blank is removed, and the mirror surface is transferred by the generated internal pressure of the resin. Then
The blank is gradually cooled by flowing a coolant such as air, water, or oil into the cooling plates 6 and 7, and the temperature of the cavity 3 is equal to or lower than the heat deformation temperature of the resin. When it becomes, the molded product is taken out. As described above, in this embodiment, the heating plates 4 are provided on both sides of the molds 1 and 2 in the mold opening direction.
5, cooling plates 6, 7 and heat insulating plates 8, 9 are provided, and these heating plates 4, 5, cooling plates 6, 7 and heat insulating plates 8, 9 are integrally attached to the die plates 10, 11, so that Type 1, 2
And be made die plates 10 and 11 are integrated, it is possible to perform quickly heated, it can also be carried out quickly within a range not to internal strain and mirror transferability problems of a molded article cooling rate, gold it is possible to reduce the size of the mold, the quality of molded products can be stabilized.

That is, the point of view of the present invention is that the heating rate is preferably as high as possible, but the cooling rate cannot be too high due to the above-mentioned mirror transferability and internal distortion. In other words, if materials with different thermal conductivities are combined appropriately, heat is transferred preferentially to materials with good thermal conductivity during heating, and materials with poor thermal conductivity have poor responsiveness, so the temperature is still sufficiently raised. do not do. In the meantime, a certain amount of heat is supplied to the material of the cavity, and it becomes higher than the glass transition point. Next, since the cooling rate is not so fast, not only materials with good thermal conductivity,
Can respond to bad materials. Therefore, if a good combination of a material with good thermal conductivity and a bad material is used, it is found that heating can be performed quickly and cooling can be performed uniformly and smoothly.
In order to achieve this, the heating plates 4 and 5, the cooling plates 6 and 7, and the heat insulating plates 8 and 9 are provided on both sides of the molds 1 and 2 in the mold opening direction.

FIGS. 2 and 3 show an embodiment of the plastic molding apparatus according to the second aspect of the present invention. First, the configuration will be described. In FIG. 2, reference numeral 21 denotes an upper die, 22 denotes a lower die, and a cavity 23 having at least one or more mirror surfaces is defined on a surface facing the upper die 21 and the lower die 22. This cavity 23 has the same shape and volume as the cavity of the injection molding die, and a thermoplastic plastic base material pre-processed into a substantially final shape by injection molding is inserted. I have. In addition, upper mold 21 and lower mold
22 shows the upper heating plate in each mold opening direction (indicated by the arrow).
24, lower heating plate 25, upper insulation plate 26, lower insulation plate 27, upper cooling plate 2
8, the lower cooling plate 29 is installed, these, each plate 24-2
9 is attached to the upper die plate 30 and the lower die plate 31.

The die plates 30 and 31 are configured to clamp and open the molds 21 and 22, and constitute a mold clamping and mold opening apparatus. Further, a plurality of heating members 24a, 25a such as electric heaters are provided in the upper and lower heating plates 24, 25, and refrigerants such as oil, water, and air are provided in the upper and lower cooling plates 28, 29. A plurality of flow passages 28a and 29a through which the air flows are formed.
The upper and lower heat insulating plates 26 and 27 are made of a member having low thermal conductivity. Next, a method of forming a formed article by such a forming apparatus will be described. First, after heating the upper and lower molds 21 and 22 around the thermal deformation temperature of the resin, a blank having a substantially final shape equivalent to the volume of the cavity 23 is inserted into the cavity 23, and then the die plate 30, 31
, After closing the molds 21 and 22,
After clamping with a constant mold clamping pressure, the heating plate 24,
25 is heated to heat the molds 21 and 22 above the glass transition point of the resin. After the temperature is controlled until the temperature reaches the glass transition point up to the center of the cavity 23, the heating is stopped.

During this time, the temperature difference between the cooling plates 28 and 29 and the heating plates 24 and 25 becomes large, and heat moves in the heat insulating plates 26 and 27. Then, although slowly, the heat in the heating plates 24 and 25 and the molds 21 and 22 moves to the cooling plates 28 and 29 through the heat insulating plates 26 and 27. Since the cooling plates 28 and 29 are controlled to a constant temperature by a refrigerant such as air or hot water, the cooling plates
The heat transferred to 28 and 29 is removed by this refrigerant. In this way, the temperature rises rapidly during heating, and is cooled at a constant rate (1 to 6 ° C./min) during cooling. As described above, in this embodiment, the upper heating plate 24, the lower heating plate 25, the upper heat insulating plate 26, the lower heat insulating plate 27, the upper cooling plate 28, and the lower cooling plate
Since the attachment 29, without performing a cooling control, it is possible to perform quickly the heating, cooling is fast within a range not to internal strain and mirror transferability problems of a molded article 且
One can be uniformly carried out, it is possible to reduce the size of the mold, the quality of molded products can be stabilized.

In the cooling method according to the present embodiment, as shown by the solid line in FIG. 3, even if the cooling control is not specially performed, the cooling can be performed quickly within a range that does not cause a problem in the internal distortion of the molded product or the mirror surface transferability. it can. In FIG. 3, a broken line indicates a conventional cooling control in which a heat pipe is provided in a mold and the heat pipe is forcibly cooled by fins. It is preferable that the molds 21 and 22 be made of a material having good thermal conductivity as much as possible. Further, a known insert unit may be provided in the molds 21 and 22, and one or more mirror surfaces may be formed on the surface of the insert unit. At this time, a material having good heat conductivity may be used for both the mold and the insert piece unit, or a material having good heat conductivity may be used only for the insert piece unit.

FIGS. 4 to 6 show another embodiment of the plastic molding apparatus according to the first or second aspect of the present invention. In this embodiment, as shown in FIG.
Heaters 41a and 42a are provided in the vicinity of the cavities 43 of 1 and 42 to improve the heat conductivity to the cavities at the time of heating, and the dies 41 and 42 and the heating plate are integrated. Also, as shown in FIG. 5, the thermal conductivity is controlled by providing a plurality of holes 44a, 45a in the upper and lower heat insulating plates 44, 45 and adjusting the sectional area in the mold opening direction, as shown in FIG. In addition, the upper and lower die plates 46 and 47 are formed with flow passages 46a and 47a through which a refrigerant such as oil, water, and air flows, and also serve as a cooling plate.

In this way, the heating plate, the heat insulating plate and the cooling plate can be integrated with each other according to the purpose, and the holes 44a and 45a are opened in the heat insulating plates 44 and 45,
The heating rate and the cooling rate can be controlled even when there is no heat insulating plate having the desired thermal conductivity. In this embodiment, the holes 44a, 45a are formed in the heat insulating plates 44, 45.
However, the present invention is not limited to this. As shown in FIG. 6, a heat insulating disk 50a having a relatively high heat conductivity is attached to a predetermined portion of the heat insulating plate 50 having a low heat conductivity, so that the heating speed and the cooling speed are increased. May be controlled. Further, the heating rate and the cooling rate may be controlled by adjusting the thickness of the heat insulating plate.

FIGS. 7 to 10 are views showing one embodiment of the plastic molding apparatus according to the third to ninth aspects of the present invention, showing a mold structure for removing three molded products. In FIG. 7, reference numerals 51 and 52 denote an upper die and a lower die base, respectively. The upper die and the lower die bases 51 and 52 are made of S55C and each have an outer diameter of a plate thickness of 40 mm. Also, in the bases 51a, 52, three cavities 53 are defined in the bases of the lower dies 51, 52.
The insert piece is made of an aluminum alloy and has a thickness of 40 mm and a width of 30 mm. The cavity 53 has one side of 10 mm and the other side of 2 mm.
0 mm and a cavity 53
A blank B made of polycarbonate having the same volume as 53 is inserted.

Outside the mold bases 51 and 52 in the mold opening direction, upper heating plates 54 and 55 made of a thermally conductive aluminum alloy or low thermal conductive Starbucks are provided.
The heating plates 54 and 55 are formed to have a thickness of 30 mm, and heating heaters 54a and 55a are provided inside. In addition, heating plate 5
Upper and lower heat insulating plates 56 and 57 are provided outside of the heat insulating plates 54 and 55, and the heat insulating plates 56 and 57 have thicknesses as shown in FIG. a is formed to 10 mm or 5 mm. Further, outside the heat insulating plates 56 and 57, upper and lower cooling plates 58 and 59 are provided.
Reference numerals 8 and 59 are made of S55C and have a thickness of 30 mm. Further, inside the cooling plates 58 and 59, there are formed flow passages 58a and 59a through which a refrigerant such as oil flows. Cooling plate
An upper die plate 60 and a lower die plate 61 are provided outside of 58 and 59, respectively.

In the present embodiment, the plate thickness of each of the above-described plates is set as described above.
Set the size, and set the temperature of the cooling plates 58 and 59 to 50 ° C and 100 ° C.
Influence of thermal conductivity of heat insulation plates 56 and 57 when the temperature is set to ℃
Temperature change near the center cavity 53 (heating rate, cooling
Rejection rate) was measured. FIG. 8 shows the thermophysical properties of each material.
Is the material of the heating plates 54 and 55, the temperature of the cooling plates 58 and 58, and the heat insulation.
4 patterns of each combination example with the plate thickness a of the plates 55 and 56
It is shown by. 10 (a) and 10 (b)
The heating rate and the cooling rate are shown, but the heating rate is 10 ° C./m
in or more and the cooling rate is 1 ° C / min or more
You can see that For example, at a heating rate of 15 ° C./min.
In this case, at 5 ° C./min, at 4 ° C./min,
Is 3 ° C./min. At this time, 4 × 10^-3cal
・ Cm ^-1・ S^-1・ ℃^-12 × 1 even without heat insulating material
0^-3cal · cm^-1・ S^-1・ ℃ ^-1Insulation board if you have the material
The same performance can be obtained by halving the thickness.
You can see that you can.

Further, since the balance between the heating rate and the cooling rate can be changed depending on the temperature of the cooling plate, a desired cooling rate can be obtained by adjusting the temperature. As a result, in this embodiment, the optimum conditions can be obtained as the following numerical values. Hereinafter, the numerical values and their effects will be described. A) Mold bases 51, 52, insert pieces 51a, 52a, heating plates 54, 5
5. By selecting each material and plate thickness of the heat insulating plates 56 and 57 as described above, the heating rate at the time of heating is 10 ° C./min or more, and the cooling rate at the time of cooling is 1 ° C./min or more. Can satisfy the conditions.

In this way, the rapid heating rate (1
0 ° C / min or more) and a smooth cooling rate (1 ° C / mi)
n or more, preferably 3 ° C./min or less before and after the glass transition point, and 6 ° C./min or less at other times. ) Is possible. As a result, the molding cycle of the molded article is shortened. In addition, the heating rate at the time of heating is 10 ° C./min or more,
The reason why the cooling rate during cooling was 1 ° C./min or more is that
If the heating rate is less than 10 ° C./min and the cooling rate is less than 1 ° C./min, the molding cycle becomes longer and the productivity is reduced. B) By setting the thickness of the heating plate to 30 mm, the heating rate can be rapidly increased, and the molding cycle of the molded article can be further shortened. Note that the thickness of the heating plate is preferably set to 10 to 50 mm. That is, if the thickness of the heating plate is less than 10 mm, the size of the electric heater or the like becomes small, resulting in insufficient heat supply. If the thickness exceeds 50 mm, the heating capacity of the heating plate increases, and the heating rate decreases unless the heat supply amount is increased. . C) By setting the thickness of the heat insulating plates 56 and 57 to 5 mm or 10 mm, the heating rate can be increased, and the cooling rate can be sufficiently obtained, thereby further shortening the molding cycle of the molded article. Can be. Preferably, the thickness of the heat insulating plates 56 and 57 is 1 to 30 mm.

That is, if the thickness of the heat insulating plate is less than 1 mm, a sufficient heat insulating effect during heating cannot be exerted, and the heating speed is reduced. If the thickness exceeds 30 mm, heating is good, but a sufficient cooling speed during cooling is obtained. Disappears. D) Mold bases 51, 52, insert pieces 51a, 52a and heating plate 5
4, the thermal conductivity of 55 is 0.05 cal · cm ^-1 · S ^-1 · ° C
By setting it to ⁻¹ or more, the heating rate can be increased, and the molding cycle of the molded article can be further shortened.

On the other hand, the mold bases 51 and 52,
The thermal conductivity of the heating plates 51 and 52a and the heating plates 54 and 55 is 0.05c.
If it is less than al · cm ⁻¹ · S ⁻¹ · ° C. ⁻¹ , the heat conductivity is poor, and the heat is not sufficiently applied to the cavity, and the heating rate is reduced. E) The thermal conductivity of the heat insulating plates 56 and 57 is 0.001 to 0.05c.
By the ^{al · cm -1 · S -1 ·} ℃ -1, it is possible to increase the heating rate, it is possible to obtain a sufficient cooling rate, is possible to further shorten the molding cycle of molded articles it can.

On the other hand, the thermal conductivity of the heat insulating plates 56 and 57 is
0.05 calcm^-1・ S^-1・ ℃ ^-1Beyond the insulation effect
As a result, the heating rate decreases, and 0.001 c
al.cm^-1・ S^-1・ ℃^-1If it is less, the cooling rate will decrease
Not preferred. F) The thermal conductivity of the cooling plates 58 and 59 is set to 0.05 cal · cm.^-1
・ S^-1・ ℃^-1As described above, the temperature is set to 50 ° C. or 100 ° C.
The cooling rate can be adjusted sufficiently.
Wear. The temperature is preferably set to 10 to 100 ° C.
Good.

On the other hand, if the thermal conductivity of the cooling plates 58 and 59 is less than this, the cooling part temperature control becomes insufficient,
When the temperature is within this range, it can be easily controlled by water cooling. As more preferable conditions, the heating plates 54 and 55
Λ ₁ , C
₁ , ρ ₁ , t ₁ , and those of the insulating plates 56, 57 are replaced by λ ₂ , C ₂ , ρ
₂ , t ₂ , when the temperature of the cooling plates 58 and 59 is T ( K ),

[0042]

(Equation 4)

However, T _O : 273K, λ: (cal · cm ⁻¹⁾
· S ^-1 · ° C ^-1 ), C: (cal · g ^-1 · ° C ^-1 ), ρ: (g · c
m ⁻³ ), so that the heating plates 54 and 55 and the heat insulating plates 56 and 5
It turns out that it is only necessary to select 7 and the cooling plates 58 and 59. In the present embodiment, by selecting each plate within the range of the above equation, the heating rate can be made very high and the cooling rate can be increased within a range that does not adversely affect the molded product. In addition, as shown in FIG.
(Indicated by a broken line), cooling may be performed by controlling to an optimum speed in each temperature range at the time of cooling.

[0044]

According to the invention of claim 1, wherein, according to the present invention, the mold and mold clamping, be made mold opening device integrated, it is possible to perform quickly the heating, internal strain of the cooling also molded article The process can be performed quickly and uniformly within a range that does not cause a problem on the mirror surface transferability, and the molded product can be molded in a short molding cycle. Further, it is possible to reduce the size of the compact and the mold of the device, the quality of molded products can be stabilized. According to the second aspect of the present invention, without performing a cooling control, it is possible to perform quickly the heating, cooling is fast and uniform within a range not to internal strain and mirror transferability problems of a molded article Can do
A molded article can be molded in a short molding cycle. Furthermore, it is possible to reduce the size of the compact and the mold of the device, the quality of molded products can be stabilized.

According to the third aspect of the invention, a rapid heating speed and a smooth cooling speed can be achieved.
The molding cycle of the molded article can be shortened. According to the fourth aspect of the present invention, the heating rate can be rapidly increased, and the molding cycle of the molded article can be further shortened. According to the fifth aspect of the present invention, the heating rate can be increased, the cooling rate can be sufficiently obtained, and the molding cycle of the molded article can be further reduced. According to the invention of claim 6, the heating rate can be increased, and the molding cycle of the molded article can be further shortened.

According to the seventh aspect of the present invention, the heating rate can be increased, a sufficient cooling rate can be obtained, and the molding cycle of the molded article can be further shortened. According to the invention described in claim 8, the cooling rate can be adjusted to a sufficient value. According to the ninth aspect of the present invention, the heating rate can be extremely high and the cooling rate can be increased within a range that does not adversely affect the molded product.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a plastic molding apparatus according to the first aspect of the present invention, and is a cross-sectional view thereof.

FIG. 2 is a view showing one embodiment of a plastic molding apparatus according to the invention of claim 2, and is a cross-sectional view thereof.

FIG. 3 is a diagram illustrating a cooling speed of the molded article of one embodiment, and is a diagram illustrating a comparison of a cooling speed with a forced cooling by a heat pipe.

FIG. 4 is a sectional view showing another embodiment of the plastic molding apparatus according to the first or second aspect of the present invention.

FIG. 5 is a diagram showing a configuration of a heat insulating plate of another embodiment.

FIG. 6 is a view showing another embodiment of the heat insulating plate.

FIG. 7 is a cross-sectional view showing one embodiment of a plastic molded article molding apparatus according to any one of claims 3 to 9;

FIG. 8 shows the material of each plate and its thermal conductivity, specific heat,
It is a figure which shows a density.

FIG. 9 is a diagram showing a material of a heating plate, a temperature of a cooling plate, and a thickness of a heat insulating plate according to one embodiment.

10A is a diagram showing the heat conductivity of the heat insulating plate with respect to the heating speed and the heating temperature in one embodiment, and FIG. 10B is the heat conductivity of the heat insulating plate with respect to the cooling speed and the cooling temperature in one embodiment. FIG.

[Explanation of symbols]

1, 21, 41 Upper die 2, 22, 42 Lower die 3, 23, 43, 53 Cavity 4, 24, 54 Upper heating plate 5, 25, 55 Lower heating plate 6, 28, 58 Upper cooling plate 7, 29, 59 Lower cooling plate 8, 26, 56 Upper insulating plate 9, 27, 57 Lower insulating plate 10, 30, 46, 60 Upper die plate (clamping and opening device) 11, 31, 47, 61 Lower die plate (mold 50 Insulation plate 51 Upper die base (die) 51a, 52a Insert (die) 52 Lower die base (die) B Blank (base material)

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Tetsuya Sonoda 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (56) References JP-A-2-311322 (JP, A) JP-A-Hei 5-124077 (JP, A) Table 3 Hei 5-505185 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B29C 69/00-69/02 B29C 33/00-33 / 76 B29C 45/00 B29C 39/00-39/44

Claims (9)

(57) [Claims] 1. A thermoplastic base material pre-processed to a substantially final shape by injection molding into a mold having a cavity having at least one mirror surface, which has the same shape and volume as the cavity of the mold for injection molding. A plastic molding apparatus that inserts, heats and melts the plastic base material above its glass transition temperature to generate a resin internal pressure in the cavity, gradually cools and transfers a mirror surface by the resin internal pressure , Provide a heating plate, a heat insulating plate, a cooling plate, the heating plate,
A plastic molding apparatus wherein a heat insulating plate and a cooling plate are closed with a mold and integrally attached to a mold opening device. 2. A heating plate, a heat insulating plate,
The plastic molding apparatus according to claim 1, wherein the cooling plates are arranged in the order of the cooling plates. 3. A mold, a heating plate, and a heat insulating plate so as to satisfy a condition that a heating rate during heating is 10 ° C./min or more and a cooling rate during cooling is 1 ° C./min or more. 3. The plastic molding apparatus according to claim 2, wherein the sheet thickness is selected. 4. The plastic molding apparatus according to claim 2, wherein said heating plate has a thickness of 10 to 50 mm. 5. The plastic molding apparatus according to claim 2, wherein said heat insulating plate has a thickness of 1 to 30 mm. 6. The heat conductivity of the mold and the heating plate is 0.0
The plastic molding apparatus according to claim 2, wherein the temperature is 5 cal · cm ^-1 · S ^-1 · ° C ^-1 or more. 7. The heat insulating plate having a thermal conductivity of 0.001 to 0.5.
Plastic molding apparatus according to claim 2, characterized in that the ^{05cal · cm -1 · S -1 ·} ℃ -1. 8. The thermal conductivity of the cooling plate is 0.05 cal ·
cm ^-1 · S ^-1 · ℃ ^-1 or more, the temperature is 10 ~ 100 ℃
The plastic molding apparatus according to claim 2, wherein: 9. The thermal conductivity, ratio, density and thickness of the heating plate are respectively λ ₁ , C ₁ , ρ ₁ and t ₁ , and those of the heat insulating plate are λ ₂ , C ₂ , ρ ₂ and t _2. , The temperature of the cooling plate is T ( K )
Then, However, T _O : 273K, λ: (cal · cm ^-1 · S ^-1 ·
° C ^-1 ), C: (cal · g ^-1 · ° C ^-1 ), ρ: (g · cm ^-3 ), characterized by the following: An apparatus for molding a plastic molded product according to claim 2.