JPH1016040A - Molding mold and molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the production of a molding having a good specular surface and a crimped surface in a short cycle by a method in which one of the pressures applied to both sides of a molding surface is made to follow/ synchronize after/with the other by the interaction between fluid supplied to a space and fluid supplied to the side of molding surface heated at a Vicat softening point or above. SOLUTION: The back 31 of a molding surface is heated by the radiation heat of a halogen heater, and the molding surface 30 is heated to a Vicat softening temperature or more. Compressed air is supplied into a parison P through piping 61, the pressure in the parison P is elevated to a prescribed value, and the outer surface of the parison P is pressed to the molding surface 30. Compressed air of the same pressure is supplied from a compressed air supply source S21 for a space B to the space B through piping 62 to pressurize the space B to a prescribed pressure. The pressure in the parison P is synchronized with the pressure in the space B so that the pressures of both sides of the molding surface 30 is equilibrated. In this way, the molding surface 30 can be made thin enough to carry out heating/cooling quickly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for blow molding thermoplastic resin and a blow molding method.

[0002]

2. Description of the Related Art As a method for obtaining a resin molded product, there are an injection molding method and a blow molding method. In the injection molding method, the molten resin is placed in a closed mold at a high pressure (200 to 1000 kg / cm).
^In this method, the molding surface of the mold is transferred to resin by injection in ² ). Because of the high pressure, the transfer of the molding surface is performed accurately. Therefore, it is suitable for obtaining a molded product having a mirror surface or a grained surface. However, since a mold that can withstand high pressure is required, the structure of the mold is complicated and the cost is high, which is not suitable for high-mix low-volume production. In addition, since a special device is required for molding a hollow product, the production process is complicated. In the blow molding method, a parison (a hollow cylindrical resin in a melted and softened state) is supplied between molds, the mold is clamped, and a fluid is pressure-fed to the hollow portion so that the outer surface of the parison is a molding surface of the mold. This is a method of transferring the image by pressing it onto Since it is pressed by the pressure of the fluid, the pressure is relatively low (4 to 10 kg / cm ² ), so that the molding surface is not transferred cleanly, which is not suitable for obtaining a molded product having a mirror surface or a grain surface. However, it is widely used because it is suitable for mass production of hollow articles. JP-A-58-102732 discloses a thin inner mold for molding,
A hollow molding die provided with a cooling outer die capable of contacting / isolating the inner molding die is disclosed. In this mold, the inner mold for molding is heated before the parison is supplied for the purpose of improving the surface gloss of the hollow molded article, and after the parison is brought into contact with the molding surface of the inner mold for cooling, it is cooled. By bringing the inner surface of the outer mold into contact with the outer surface of the inner mold for molding, the inner mold for molding is rapidly cooled to obtain a molded product. JP-A-4-77231
In the gazette, when the parison is brought into contact with the molding surface of the mold, the temperature of the mold is maintained between a temperature near the maximum crystallization speed of the parison and a melting point. Blow molding that prevents die lines and weld lines from remaining on the surface of the molded product and circulates refrigerant through the hollow part of the parison during molding to prevent a prolonged molding cycle time. A method is disclosed. In Japanese Patent Publication No. 6-73903,
A lid having good heat conductivity and a large number of through-holes is fixed to a container-like mold frame to form a mold surface area including the lid and an intermediate layer behind the mold, and the intermediate layer is formed. There is disclosed a molding die in which a resin or metal having low heat conductivity is filled, or a reinforcing rib provided with a conduction hole is provided.

[0003]

There is a demand for obtaining a resin molded product having a mirror surface or a grain surface using a mold having a relatively simple structure. There is also a demand for producing a hollow resin molded product having a mirror surface or a grain surface (eg, an air spoiler of an automobile) by a simple process. JP-A-58-1
In the mold for hollow molding disclosed in Japanese Patent No. 027334, the molding surface is clearly transferred by heating the molding inner mold. However, the molding inner mold is relatively displaced and brought into contact with the cooling outer mold. Since the resin is cooled by the method, the structure of the mold may be complicated and weakened, and the cooling time may be prolonged. Further, there is no mention of the optimum range of the heating temperature and the cooling temperature for cleaning the surface of the resin molded product and shortening the entire cycle time of the molding. JP-A-4-77
In the blow molding method of JP-A-231-231, the molding surface is cleaned by heating and maintaining the temperature of the mold at the above-mentioned temperature. The effect is not very large. Further, since the parison is cooled from the inside by circulating the refrigerant, temperature control for heating and maintaining the temperature of the mold at the above-mentioned temperature becomes complicated. In the apparatus disclosed in Japanese Patent Publication No. Hei 6-73903, heating and cooling of a molding surface are performed by heating a large number of conduction holes provided inside or on the back surface of a lid (mold surface area) on which the molding surface is formed.・ It is performed by passing a cooling medium, and also by sending a heating / cooling medium into the intermediate layer behind the molding surface, but in this device, the heat transfer in the intermediate layer is slow. Therefore, it is difficult to shorten the cycle time. An object of the present invention is to produce a resin molded product having a good mirror surface or grain surface in a relatively short cycle time. It is another object of the present invention to produce a resin molded product having a good mirror surface or grain surface in a relatively simple process. Another object of the present invention is to increase the durability of the mold by reducing the force applied to the components of the mold, or to enable molding with a low-cost and highly durable mold.
Another object is to improve the heat efficiency of heating / cooling. It is another object of the present invention to provide a molding die capable of heating a molding surface to a high temperature and adjusting the pressure on the front and back of the molding surface.

[0004]

According to the first aspect of the present invention, there is provided a mold provided with a molding surface for pressing a molten thermoplastic resin against a molding surface so that the thermoplastic resin adheres to and solidifies the molded resin. (A) Near the molding surface in order to heat the molding surface to a temperature equal to or higher than the Vicat softening temperature (T) ° C. of the thermoplastic resin. (B) cooling means for cooling the molding surface to a temperature not higher than (Vicat softening temperature (T) -10) ° C. of the thermoplastic resin; (C) supplying a fluid to the space. A fluid supply mechanism that pressurizes the back surface of the molding surface by the pressure of the fluid, supplies a fluid to the molding surface side, and presses the thermoplastic resin against the molding surface by the pressure of the fluid; Fluid supplied and supplied to the molding surface side A pressure adjusting mechanism that causes one of the pressures respectively applied to the front and back surfaces of the molding surface to follow the other by the interaction of the fluid and synchronizes the two with each other; The phrase “the pressure of a follows the pressure of b” is defined herein as “the pressure of a approaches the pressure of b due to the action of the pressure of b”. This definition does not necessarily mean the same as the case where “in the graph showing the pressure fluctuation, the pressure fluctuation of“ a ”rises or falls so that the pressure fluctuation of“ b ”follows the pressure fluctuation of“ b ””. Further, "the pressures on the front and back surfaces of the molding surface are synchronized" in the present specification means that "the pressures on the front and back surfaces of the molding surface are substantially equal to the extent that the molding surface does not deform or impair the durability of the molding surface. Is defined. According to a second aspect of the present invention, in the first aspect of the present invention, the heating means (A)
A blow molding die comprising a means for heating at least one of the molding surface side and the back surface side of the molding surface by a non-fluid heating method. As a non-fluid heating method, for example, there is a means for electrically heating the molding surface. Here, as means for electrically heating the molding surface, for example, the molding surface is constituted by a heater having a relatively high electric resistance value, and means for heating by energizing the heater, high-frequency induction heating, Means for heating the molding surface by heating, or means for heating the molding surface by dielectric heating. As a non-fluid heating method, for example, there is a means for heating the molding surface side, the rear surface side of the molding surface, or the molding surface side and the rear surface side of the molding surface by radiant heating. The means for heating the back side of the molding surface can be realized, for example, by providing a halogen heater so as to face the back surface of the molding surface. According to a third aspect of the present invention, in any one of the first and second aspects of the present invention, the pressure adjustment mechanism (D) includes a piping path for supplying a fluid to the molding surface side, and the space. This is a blow molding die, which is a mechanism that communicates with a piping path for supplying a fluid to the mold. A fourth aspect of the present invention is the pressure adjusting mechanism (D) according to any one of the first and second aspects.
However, a pipe line for supplying a fluid to the molding surface side, a pipe line for supplying a fluid to the space, a cylinder displaceably provided with a piston balanced by the pressure of the fluid in both the pipe lines. This is a blow-molding die, which is a mechanism that is connected via a through hole.

[0005] In any of the above inventions, further: (J) the supported portion around the mold and the supporting portion of the mold body corresponding to the supported portion are gently provided with play. A fitting member provided on the supported portion and the support portion to absorb the relative displacement generated between the supported portion and the support portion due to the fitting and thermal expansion by the play; (L) a seal member provided at the play portion of the member; (L) a thermal conductivity provided between the supported portion of the mold body and the support portion of the mold body; / mh
° C] and the modulus of longitudinal elasticity is 0.1 × 10 ⁴ -100 ×
The blow molding die may be configured to have 10 ⁴ [kg / cm ² ] of a heat insulating support member. According to a fifth aspect of the present invention, there is provided the blow molding die according to any one of the first to fourth aspects, wherein the molding surface has a (Vicat softening temperature (T)
+100) The modulus of longitudinal elasticity at ℃ is 0.01 to 10 [kg /
cm ² ], a parison using a thermoplastic resin is supplied, a fluid is introduced into the space or the divided space at a pressure of 100 kg / cm ² or less, and a fluid that synchronizes with the fluid by interacting with the fluid is introduced. At the same time, the outer surface of the parison is pressed against and adhered to the molding surface, and the molding surface is heated to a Vicat softening temperature (T) ° C. or higher, and the molding surface is heated to (Vicat softening temperature (T) −10). This is a blow molding method in which a molded product is obtained by cooling to a temperature of not more than ° C. Thus, in the above-described invention, since the forming surface is heated by the heating means (A),
The heating time can be shortened. That is, as compared with a method in which heating steam is continuously supplied into the space on the rear surface side of the molding surface to heat the molding surface, the temperature of the molding surface can be quickly increased. Further, the temperature of the molding surface can be raised to a high temperature which cannot be achieved by the above-described heated steam supplied in the space on the back surface side of the molding surface so as to be balanced with the blow pressure. Also, as compared with the case of heating using the above-described heating steam, the switching time from the heating process to the cooling process can be reduced, so that the molding cycle can be shortened, and further, the time for discharging the heating steam is unnecessary. Therefore, the cooling is quick, and the cooling process is shortened.

The thermoplastic resin material molded by the molding die or the molding method preferably has a modulus of longitudinal elasticity at (Vicat softening temperature (T) +100) ° C.
01 to 10 [kg / cm ² ], more preferably 0.05 to 2 [k]
g / cm ² ], particularly preferably 0.1 to 1 [kg / cm ² ]. Examples of such a thermoplastic resin include styrene-acrylonitrile copolymer (AS resin), polystyrene, high-impact polystyrene, acrylonitrile-butadiene rubber-
Graft copolymer composed of styrene (ABS resin), graft copolymer composed of acrylonitrile-butadiene rubber-styrene-α-methylstyrene (heat-resistant ABS resin), acrylonitrile-ethylene-propylene rubber-styrene and / or methyl methacrylate (AES resin), graft copolymer of acrylonitrile-hydrogenated diene rubber-styrene and / or methyl methacrylate, graft copolymer of acrylonitrile-silicone rubber-styrene and / or methyl methacrylate Coalescence, polyethylene, polypropylene, polycarbonate, polyphenylene ether, polyoxymethylene, nylon, methyl methacrylate polymer, polyether sulfone, polyarylate, vinyl chloride, maleimide compound Styrene and / or acrylonitrile and / or consisting of α- methylstyrene copolymer, rubber-like polymer - maleimide compounds - styrene and /
Or graft copolymers of acrylonitrile and / or methyl methacrylate and / or α-methylstyrene, and composites thereof, and resins obtained by adding a filler to these.

[0007] Molded articles molded by the molding dies and molding methods include, for example, housings, sports products, playground equipment, vehicle products, furniture products, sanitary products,
Products for building materials, products for kitchens, wherein the molded product has a foamed layer in a hollow portion, the molded product is produced by a multilayer blow molding method, and the molded product is plated, sputtered, or vapor-deposited. , Is a painted molded article. Specific examples of these molded articles include, as a housing, a cooler box, a TV, an audio device, a printer, a facsimile, a copier, a game machine, a washing machine, an air conditioner, a refrigerator, a vacuum cleaner, an attache case, a musical instrument case, and a tool. There are boxes, containers, camera cases, etc. Sports products include, for example, swimming boards, surfboards,
Windsurfing, skiing, snowboarding, skateboarding, ice hockey stick, curling ball, gateball racket, tennis racket, canoe,
There are boats. Examples of the playground equipment include a bat, a block, a building block, a fishing gear case, a pachinko underframe, and the like. Products for vehicles include, for example, air spoilers, doors, bumpers, fenders, bonnets, sunroofs,
There are rear gate, wheel cap, instrument panel, glove box, console box, armrest, headrest, fuel tank, driver's seat cover, trunk tool box, etc. Furniture products include, for example, drawers,
Desk top plate, bed top plate / bottom plate, mirror base frame plate, grated box plate / front door, chair back plate / bottom plate, tray / tray, umbrella stand, vase, medicine box, hanger, makeup box, storage box board, book stand, office work There are a desk top plate, an OA desk top plate, and an OA rack. Sanitary products include, for example, shower heads, toilet seats, toilet plates, drain pans, water tank lids, vanity doors, bathroom doors, and the like. Examples of building material products include ceiling boards, floor boards, wall boards, window frames, doors, benches, and the like. Examples of kitchen products include cutting boards and kitchen doors. Examples of the molded article having the foam layer in the hollow portion include a refrigerator front door and a cooler box. Examples of the molded article manufactured by the multilayer blow molding method include a fuel tank and the like. Examples of the molded product on which the molded product is plated, sputtered, vapor-deposited, and painted include, for example, vehicle exterior parts and electronic equipment soldering. In addition, these are illustrations, and molded articles other than these can also be suitably molded.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION

(A) Heating Unit The heating unit can be configured using, for example, a unit that heats at least one of the molding surface side and the back surface side of the molding surface by a non-fluid method. Further, the heating means is not only a case where only the means for heating in the non-fluid method is used,
It can also be configured by using a fluid heating means in combination with the non-fluid heating means. As a mode of this combination, (1) heating is started by any of the non-fluid system or the system using both the non-fluid system and the fluid system, and when the heating is switched to heating only by the non-fluid system in the middle,
(2) There are cases where the non-fluid system and the fluid system are used together over the entire heating process. The fluid heating means refers to a method in which a heating fluid such as heating steam, heating air, heating oil, or the like is continuously supplied into a space on the back surface side of the molding surface to perform heating. In other words, the method uses a heating fluid as the fluid of the fluid supply mechanism (c). The non-fluid heating method can be realized, for example, by forming the molding surface with a conductor, forming the molding surface back side with a nonconductor, and providing a means for electrically heating the molding surface composed of a conductor. . Techniques for electrically heating a molding surface made of a conductor include (1)
There is a method in which the molding surface is made of a material having a relatively high electric resistance value, and a current is applied to the molding surface to heat it electrically. Also, at least the back side of the molding surface may be made of a dielectric, and the dielectric may be dielectrically heated to realize the non-fluid heating method. Further, the non-fluid heating method can also be realized by using means for radiantly heating at least one of the back surface of the molding surface and the molding surface. The means for radiantly heating the back surface of the molding surface is provided in a space on the back surface side of the molding surface,
This can be realized by providing a radiant heating unit such as a halogen heater in opposition to the back surface. In order to improve the heat absorption of the rear surface of the molding surface to be radiantly heated and efficiently raise the temperature of the molding surface, a surface treatment portion having good heat absorption may be provided on the rear surface of the molding surface. This surface treatment section (a) performs surface treatment on the rear surface of the molding surface,
(B) Apply a paint with good heat absorption properties to the back side of the molding surface,
(C) It can be configured by a method such as increasing the surface area of the back surface of the molding surface to increase the heat absorption. The above (a) includes a carburizing method, a cyaniding method, a nitriding method, a metal infiltration method, an electric plating, a hot dip plating, a metal spraying method, a vacuum deposition method, and fading. The above (b) includes application of a dark paint, black dyeing, application of a light selective absorbing paint, and application of a heat ray absorbing paint. As the above (c), there are mountain cutting and grooving sandblasting. These can be used in combination. As described above, since the rear surface of the molding surface can be subjected to a process for improving heat absorption, the radiation heating method generally involves heating the rear surface side of the molding surface, It is more suitable than a heating method. Since the molding surface to which the molten resin is pressed and adhered is heated to the Vicat softening temperature (T) ° C. or higher by the heating means (A), the molding surface can be transferred to the surface of the resin neatly. The transferability of the surface and the mirror surface is improved. Further, since the heating means (A) is not used as a fluid for pressurizing the back side of the molding surface and is configured as a separate member, the heating medium is continuously supplied to the space on the back side of the molding surface in the heating process. Supply and discharge to
The space can be configured as a closed space. For this reason, the pressure in the space on the back surface side of the molding surface in the heating process is quickly increased. Therefore, it is easy to synchronize the pressure of the space in the parison, which is a closed space, with the pressure of the space on the back surface side of the molding surface. Therefore, the molding surface can be made sufficiently thin, and the time required for heating / cooling can be further reduced.

(B) Cooling means The cooling means can be constituted by a mechanism for supplying cooling air or cooling water into the space on the back side of the molding surface. That is, the cooling means (B) can be configured by using cooling air or cooling water as the fluid of the fluid supply mechanism (C) (fluid supplied to the space on the back side of the molding surface). Since the molding surface is rapidly cooled to (Vicat softening temperature (T) -10) ° C. or lower by the cooling means, the molded product can be quickly removed from the mold, and the molding cycle can be shortened. When the cooling means is configured as described above, it is desirable to take measures against rust on the mold body and the mold. For example, it is desirable to use a stainless steel, a copper alloy, a ceramic, an aluminum alloy, or the like, which does not easily rust, as the material of the mold body and the mold. Particularly, stainless steel is preferable. The rust-preventing function may be realized by a passivation treatment (for example, nitriding treatment) on the metal surface, application of a rust-preventive paint, application of a silicone-based sol-gel type paint, or the like.

(C) Fluid supply mechanism The fluid supply mechanism is a mechanism for supplying a pressurized fluid to the front and back surfaces of the molding surface, that is, the space on the rear surface side of the molding surface and the parison on the front surface side of the molding surface. This fluid supply mechanism can be constituted by a supply source of pressurized fluid and piping. The supply source for supplying the pressurized fluid to the space on the back side of the molding surface and the supply source for supplying the pressurized fluid to the parison may be common or may be separate. In the present invention, as described above, since the space on the back surface side of the molding surface can be configured as a closed space, it is relatively easy to synchronize the pressure on the front and back of the molding surface. In the cooling step, the cooling medium for the cooling means (B) can be used as a fluid to be supplied to the space on the back side of the molding surface. The cooling medium includes cooling water, cooling air, cooling oil, and the like.

(D) Pressure Adjustment Mechanism The pressure adjustment mechanism may be any mechanism that allows one of the pressures applied to the front and back of the molding surface to follow the other.
That is, the pressure of the fluid supplied into the parison on the front side of the molding surface may be made to follow the pressure of the fluid supplied to the space on the rear surface side of the molding surface. The pressure of the supplied fluid may be made to follow the pressure of the fluid supplied into the parison on the front side of the molding surface.
Also, this relationship is a step-up step or step-down step, or, depending on the shape of the molding surface and the like, the former and the latter,
It may be replaced in the molding process as appropriate. In the present invention, as described above, since the space on the back surface side of the molding surface can be configured as a closed space, it is relatively easy to tune the pressure on the front and back of the molding surface, and over both processes of molding, The pressure in the space can be kept substantially equal. For this reason, when following the pressure, which is “main” and which is “sub”
It doesn't matter much. In addition, since the pressure on the front and back surfaces of the molding surface can be maintained substantially equal throughout the entire molding process, the molding surface can be configured to be sufficiently thin, so that the transferability of the molding surface is improved and the required heating / cooling is required. The time can be reduced sufficiently. The pressure adjusting mechanism having such a function can be configured by, for example, connecting respective pipes for supplying fluid to the front and back of the molding surface. Further, instead of such communication between the two pipes, the pipe path for supplying the fluid to the molding surface side and the pipe path for supplying the fluid to the space are balanced by the pressure of the fluid in both the pipe paths. It is also possible to synchronize the pressures in the respective pipes by interaction by connecting the pistons via cylinders which are displaceably provided.

(J) Fitting member In FIG. 4, the fitting member gently fits the convex portion 36 around the mold 3 into the concave portion 46 at the corresponding portion of the mold body 4 with play. The mechanism and, conversely, the convex portion (not shown) of the corresponding part of the mold body 4 in the concave portion (not shown) around the mold body 3
Is a mechanism that fits loosely with play. Such a mechanism is provided on the entire area or a part of the periphery of the mold 3. Since it is loosely fitted with play,
Even when relative displacement occurs due to thermal expansion between the mold and the mold body 4, the difference can be absorbed to prevent problems such as distortion and damage.

(K) Seal Member As the seal member, an O-ring, oil seal, synthetic rubber, metal, felt, leather, cork, or the like can be used. As shown in FIG. 4, the joint between the mold body 3 and the mold body 4 can be sealed by this seal member, so that pressurized air injected into the space B on the back side of the molding surface or cooling air / cooling Water can be prevented from leaking from the connection between the mold 3 and the mold body 4. Since the molding surface 30 is heated to the Vicat softening temperature (T) ° C. or higher, the sealing member is required to be a material having durability at this temperature.

(L) Heat-insulating support member The heat-insulating support member has a thermal conductivity of 0.001 to 1 [kca
l / mh ° C], preferably 0.005 to 0.8 [kcal / mh ° C]
, More preferably 0.01 to 0.5 [kcal / mh ° C],
And the longitudinal elastic modulus is 0.1 × 10 ^{4 to} 100 × 10
⁴ [kg / cm ² ], preferably 0.2 × 10 ⁴ to 40 × 10
⁴ [kg / cm ² ], more preferably 1 × 10 ^{4 to} 20 × 10
⁴ [kg / cm ² ] of the material. The heat insulating support member has a thermal conductivity of 0.001 to 1;
[kcal / mh ° C], preferably 0.005 to 0.8 [kcal / mh
° C], more preferably 0.01 to 0.5 [kcal / mh ° C], and a modulus of longitudinal elasticity of 0.1 × 10 ^{4 to} 100 × 10
⁴ [kg / cm ² ], preferably 0.2 × 10 ⁴ to 40 × 10
⁴ [kg / cm ² ], more preferably 1 × 10 ^{4 to} 20 × 10 ⁴ [k
g / cm ² ]. In other words, it is only required that the mold body and the mold body can be supported in a heat-insulated state, and that the mold body can be reliably supported by the mold body without rattling against the pressing force applied from the mold body side to the mold body side. The reason why the above range is indicated as the thermal conductivity of the heat insulating support member is that the thermal conductivity is 0.001 [k
If the temperature is lower than cal / mh ° C, a special material is required, which is not practical. If the temperature exceeds 1 kcal / mh ° C, a desired heat insulating effect cannot be obtained. Further, the reason why the above range is indicated as the longitudinal elastic modulus of the heat insulating support member is that if the longitudinal elastic modulus is less than 0.1 × 10 ⁴ [kg / cm ² ], the rigidity is insufficient and the seal is insufficient, If it exceeds 100 × 10 ⁴ [kg / cm ² ], it becomes difficult to process the heat insulating support. Thermal conductivity required for heat-insulating support members is 0.001 to 1 [kcal / mh]
° C] and the longitudinal elastic modulus is 0.1 × 10 ^{4 to} 100 × 10
⁴ [kg / cm ² ] materials include polyarylate, polyetheretherketone, polyphenylene oxide, modified polyphenylene oxide, polyamide, acetal resin, ethylene tetrafluoride resin, ceramics, PC, phenolic resin, urea, melamine, Glass, unsaturated polyester, and the like. Preferred are phenol resins, urea resins, melamine, and unsaturated polyesters, and more preferred are phenol resins.

FIG. 1 is a schematic longitudinal sectional view showing an example of a mold apparatus according to the present invention. The illustrated mold includes a mold 3 having a molding surface 30 and the mold 3.
And a mold body 4 for supporting the mold body 3. Both the mold body 3 and the mold body 4 are made of stainless steel. FIG. 4 shows a corner portion of an attachment structure for attaching the mold body 3 to the mold body 4 of the mold apparatus of FIG. As shown in FIG. 4, a supported plate 36 projecting around the periphery of the mold body 3 has a play A in a groove 46 provided in the mold body 4 so as to correspond to the supported plate 36.
And is loosely fitted,
The mold 3 is supported by the mold body 4. The groove
Reference numeral 46 denotes a structure in which a main body plate 400 having an overhang portion 400a is attached to a main body portion 401 with bolts 403. FIG.
As shown in (a), the corners of the four main body plates 400 arranged in a rectangular shape in a top view of the molding surface 30 are adjacent to the adjacent main body plates 400.
Is provided with a gap S of about 0.1 [mm]. Further, a heat insulating layer (heat insulating support member) 1 made of a phenol resin having a thickness of 10 [mm] is provided on the surfaces of both opposing walls of the groove 46. An O-ring 9 is fitted in the gap. As a result, the mold 3 and the mold body 4 thermally expand due to the heat generated during the molding of the molten resin, and the supported plate 36
Even if there is a relative deviation between the groove 3 and the groove 46, the deviation is absorbed by the play A, and adverse effects (bending, distortion, shortening of life, etc. of the mold 3) are prevented. Also,
A precise molded product can be obtained. Further, the mold body 3 meets the conditions of the present invention (the longitudinal elastic modulus is 0.1 × 10 ^{4 to} 100 × 10
⁴ Thermal insulation layer 1 of phenolic resin that fills [kg / cm ² ] material
Since it is supported by the mold main body through the above, troubles such as rattling are prevented.

Between the back side of the mold 3 and the mold body 4,
A space B is formed. This space B is the O-ring
9 to seal the space B from the outside, pressurized air injected into the space B from the pressurized air supply source S11 through the pipe 62 and the open valve 65 during the heating process, and a cooling water supply source during the cooling process. Cooling water (and cooling air) injected into the space B from S12 is connected to the connection between the mold 3 and the mold body 4 (the part where the mold 3 is supported by the mold 4 = supported plate).
36 and the groove 46), the pressure in the space B generated at that time decreases, and the parison
Forming surface 30 caused by the pressure balance with P side being broken
Is prevented from bending. In the heating process, the power supply 51
3, the mold body 3 is electrically heated (or high frequency induction heating may be performed), and the Vicat softening temperature (T) ° C.
The temperature is raised to above. In the heating process, pressurized air is supplied from the pressurized air supply source S11 into the parison P through the pipe 61. As a result, the pressure inside the parison P 2 is increased to a predetermined pressure, and the outer surface of the parison P 2 is pressed against the molding surface 30. Further, the pressurized air supplied from the pressurized air supply source S11 is also supplied into the space B through the pipe 62 communicating with the pipe 61 and the valve 65 in an open state.
The pressure in B is increased to the predetermined pressure. Thus, the pressure in parison P and the pressure in space B are synchronized, and as a result,
Since the pressures on the front and back of the molding surface 30 are balanced, the molding surface 30 can be made sufficiently thin, and heating / cooling can be performed quickly. During the heating process, the drain valve 67
Is closed. During the cooling process, the pressurized air supply
When the supply of the pressurized air from S11 is stopped, the valve 65 is switched to the closed state, and thereafter, the cooling water supply source S1
When the supply of cooling water (and cooling air) from 2 is started, the drain valve 67 is opened. This allows
The molding surface 30 is cooled from the back surface 31 side, and is cooled to (Vicat softening temperature (T) -10) C or lower. As described above, since the molding surface 30 is configured to be sufficiently thin, the temperature is rapidly reduced.

As shown in FIG. 4B, a 10 mm thick phenol resin layer is formed on the inner surface of the mold body 4.
Since the heat insulating layer (heat insulating member) 2 including the asbestos layer 22 and the asbestos layer 21 having a thickness of 2 [mm] is provided, the heat in the space B escapes through the mold main body 4 and the heat of the external The problem of being transmitted to the space B through the mold body 4 is prevented. For this reason, the cooling effect of the cooling water (and cooling air) supplied into the space B on the molding surface back surface 31 is enhanced. Insulation material
Other materials include polyarylate, polyether ether ketone, polyphenylene oxide, modified polyphenylene oxide, polyamide, acetal resin, tetrafluoroethylene resin, ceramics, PC, urea, melamine, glass, unsaturated polyester, etc. , Rigid urethane foam, rock wool, glass wool, calcium silicate, polystyrene foam, water-repellent pearlite, cork, wood (cedar), rubber, quartz glass, foam beads, etc., and a combination of two or more of these Can be. Preferably, phenolic resin, urea,
Melamine, unsaturated polyester, asbestos, rigid urethane foam, foam beads can be used.

FIG. 2 is a schematic longitudinal sectional view showing an example of a mold apparatus of the present invention different from FIG. The mold of FIG. 2 also has a mold body 3 having a molding surface 30 and a mold body 4 supporting the mold body 3 similarly to the mold of FIG. It is. The mounting structure for attaching the mold body 3 to the mold body 4 of the mold apparatus of FIG. 2 is the same as that of the mold apparatus of FIG. The same components as those of the mold apparatus of FIG. 1 are denoted by the same reference numerals,
The description is omitted. The mold apparatus of FIG. 2 is different from the mold apparatus of FIG. 1 in that (1) the heating means (A) is replaced with the electric heating (or high frequency induction) heating of FIG. The halogen heater 5 is provided so as to face the base 31, and the molding surface back surface 31 is heated by the radiant heat. (2) As a pressure adjusting mechanism (D), the communication between the pipe 61 and the pipe 62 in FIG. A cylinder 69 having a piston 69a is interposed between the pipe 61 and the pipe 62. Although a cooling water supply source is not shown in FIG. 2, it is assumed that the cooling water supply source is provided like a pressurized air supply source S22 for the space B.

In the heating process, the halogen heater 5 is turned on, and the back surface 31 of the molding surface is heated by the radiant heat, whereby the molding surface 30 is heated to the Vicat softening temperature (T) ° C. or higher. In the heating process, pressurized air is supplied from the parison pressurized air
Supplied in P. As a result, the pressure inside the parison P 2 is increased to a predetermined pressure, and the outer surface of the parison P 2 is pressed against the molding surface 30. Also, from the pressurized air supply source S21 for the space B,
Pressurized air having the same pressure as described above is supplied to the space B through the pipe 62, and the pressure in the space B is increased to the predetermined pressure. At this time, even if there is a slight difference between the pressure in the pipe 61 and the pressure in the pipe 62, the small difference is absorbed by the displacement of the piston 69a in the cylinder 69. Are maintained at the same pressure. At this time, the drain valve 67 is closed. Thus, the pressure in the parison P and the space B
Since the internal pressure is synchronized and the pressures on the front and back of the molding surface 30 are balanced, the molding surface 30 can be configured to be sufficiently thin as in the case of FIG. it can. During the cooling process, a pressurized air supply for the parison
The supply of pressurized air from the pressurized air supply source S22 for S21 and the space B is stopped. Next, a cooling water supply source S12 (not shown)
When the supply of cooling water (and cooling air) is started, the drain valve 67 is opened. As a result, the molding surface 30 is cooled from the back surface 31 side, and is cooled to (Vicat softening temperature (T) -10) ° C. or lower. As mentioned earlier,
Since the molding surface 30 is configured to be sufficiently thin, the temperature is reduced quickly.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Using a molding die shown in FIGS.
ABS45A (manufactured by Nippon Synthetic Rubber Co., Ltd./Vicat softening temperature: 105 [kg / cm ² ] at 205 ° C./205° C.) was used as a thermoplastic resin material, and IPB was used as a blow molding machine. Using EP-55 (manufactured by Ishikawajima-Harima Heavy Industries, Ltd.), blow molding was performed under the following conditions. That is, the conditions are as follows: (1) Extruder temperature: 220 ° C. (2) Clamping force: 15 ton (3) Parison blowing pressure and supply pressure of space B: 6 kg / cm ² (4) Heating of molding surface 30 Case: Electric heating (or high-frequency induction) heating In the case of FIG. 2: Radiation heating of a halogen heater Final temperature of the molding surface 30: 140 to 150 ° C. Heat holding time of the molding surface 30: 10 seconds (5) Cooling of the molding surface 30 Cooling water Supply pressure from supply source S12: 6 kg / cm ² Final cooling temperature of molding surface 30: 70 ° C. Cooling holding time of molding surface 30: 60 sec (6) Total process time: 150 sec. As a result, the pressure in the parison P and the pressure in the space B changed as shown in FIGS. That is, the two pressures changed in synchronism, and the inside of the parison P and the inside of the space B were maintained at substantially the same pressure throughout the entire molding process. Therefore, even when the thickness of the molding die 3 was sufficiently reduced, it was possible to sufficiently withstand the pressure applied from the parison P side. In addition, since the thickness of the molding die 3 can be reduced, the weight can be reduced, and heating / cooling from the back side of the molding surface can be performed quickly, and the molding cycle can be shortened, and the mirror finish of the molded product can be improved. Was. In addition, when the molded product (Example product) molded in this way is compared with the molded product (Comparative example product) molded without heating the molding surface 30 described above (4), the surface gloss of the Example product is The degree was uniformly 95% over the entire surface of the molded article, and the R of the corner was 0.5 or less, while the surface gloss of the comparative example was 20%.
Below, R of the corner part was 0.5 or more. That is, the transfer of the molding surface of the example product is better than that of the comparative example product, and the corner portion R which cannot be obtained by the conventional blow molding is obtained.
However, a small molded product could be molded with high accuracy, and the dimensional stability was excellent. The outside dimensions of the mold: 460 (L) x 560 (W) x 720
(H) [mm] Molded product size: 120 (L) x 40 (W) x 480 (H) [mm] Dimension of space B: 70 (L) x 70 (W) x 500 (H) [mm] is there.

[0021]

According to the present invention, since the pressure in the parison P and the pressure in the space B can be synchronized and balanced, the force applied to the cavity can be reduced and the life of the mold can be extended. In addition, a low-cost mold can be used. Further, the heat efficiency of heating / cooling is excellent. Also,
Since the mold can be made thin, it has a uniform and good mirror surface and grain surface over the entire surface of the molded product, and a resin molded product with excellent dimensional stability can be manufactured with a relatively short cycle time. Can be produced.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a mold embodying the present invention.

FIG. 2 is a schematic view showing an example different from FIG. 1 of a mold embodying the present invention.

FIG. 3 is an explanatory diagram showing pressures in a space B and a parison of the mold shown in FIGS. 1 and 2;

4A and 4B show a mounting structure of a corner portion of the mold shown in FIGS. 1 and 2, wherein FIG. 4A is a view as viewed from a molding surface 30 side, and FIG. 4B is a sectional view taken along line BB of FIG.

[Explanation of symbols]

 3 Mold body (heater) 4 Mold body 5 Halogen heater 30 Molding surface B Space P Parison 61, 62 Piping

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location B29L 22:00

Claims (5)

[Claims] 1. A mold provided with a molding surface for pressing and adhering a molten thermoplastic resin to a molding surface so as to be adhered and solidified, and a mold having a space secured between the molding body and the back surface of the molding surface. (A) (B) (C)
(D) a blow molding die having the respective constitutional requirements: (A) provided near the molding surface to heat the molding surface to a temperature equal to or higher than the Vicat softening temperature (T) ° C. of the thermoplastic resin. Heating means; (B) cooling means for cooling the molding surface to a temperature not higher than (Vicat softening temperature (T) -10) ° C. of the thermoplastic resin; (C) supplying a fluid to the space and pressure of the fluid; A fluid supply mechanism that pressurizes the back surface of the molding surface, supplies a fluid to the molding surface side, and presses the thermoplastic resin against the molding surface by the pressure of the fluid; (D) a fluid supplied to the space And a fluid supplied to the molding surface to cause one of the pressures applied to the front and back surfaces of the molding surface to follow the other, thereby synchronizing the two. 2. The blower according to claim 1, wherein the heating means (A) heats at least one of the molding surface side and the back surface side of the molding surface by a non-fluid heating method. Mold for molding. 3. The pressure adjusting mechanism (D) according to claim 1, wherein the pressure adjusting mechanism (D) includes a pipe for supplying a fluid to the molding surface side and a pipe for supplying a fluid to the space. ,
A blow molding die that is a mechanism for communication. 4. The pressure adjusting mechanism (D) according to claim 1, wherein the pressure adjusting mechanism (D) includes a pipe for supplying a fluid to the molding surface side and a pipe for supplying a fluid to the space. ,
A blow-molding die, which is a mechanism for connecting pistons balanced by the pressure of fluid in both piping paths via a cylinder provided to be displaceable. 5. The method according to claim 1, wherein the molding surface of the blow molding die according to any one of claims 1 to 6 is provided with (Vicat softening temperature (T) +
100) The modulus of longitudinal elasticity at ℃ is 0.01 to 10 [kg / cm]
² ] A parison using a thermoplastic resin is supplied, and a fluid is introduced into the space or the divided space at a pressure of 100 [kg / cm ² ] or less, and a fluid that interacts with the fluid and tunes The outer surface of the parison is pressed against and tightly adhered to the molding surface with pressure, and the molding surface is heated to a Vicat softening temperature (T) ° C. or more, and the molding surface is heated to (Vicat softening temperature (T) −10) ° C. A blow molding method for obtaining a molded product by cooling to the following temperature.