JPH0999480A - Blow molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a mold having a good mirror surface or embossed surface on the outer surface thereof and having a foamed layer therein by short cycle blow molding by foaming a foaming component to pressurize a parison from the hollow inferior thereof and closely bonding the outer surface of the parison to a molding surface under specific pressure and subsequently cooling the molding surface to specific temp. SOLUTION: A parison P is suspended between molding surfaces 30, 30 and, after the hollow part of the parison P is hermetically closed, air is supplied from an air supply source 90 to press the outer surface of the parison P to the molding surfaces under pressure of 100[kg/cm<2> ] or less to closely bond the same to the molding surfaces. At the same time, a foaming component P1 is supplied and, further, heated steam is injected to the space B on the rear side of the molding surfaces from a nozzle 70. By this constitution, the foaming component P1 in the hollow part of the parison is foamed to expand throughout the hollow part of the parison. Next, the heating steam in the space B is discharged to expand troughout the hollow part of the parison P. Next, the heating steam in the space B is discharged and cooling water + cooling air is injected into the space B through the nozzle 70. By this constitution, the prison P is rapidly cooled to (Vicat softening temp. -10 deg.C) or lower.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blow molding method of thermoplastic resin and a blow molded article. In particular, the present invention relates to a molded product having a foamed portion inside the molding surface and a method for obtaining the molded product.

[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. The injection molding method uses high pressure (200 to 1000 kg / cm) in a mold in which molten resin is sealed.
^This is a method of injecting in ² ) and transferring the molding surface of the mold to the resin. Since the pressure is high, the molding surface is accurately transferred. Therefore, it is suitable for obtaining a molded product having a mirror surface or a grain surface. However, because a mold that can withstand high pressure is required,
The structure of the mold becomes complicated and the cost becomes high, which is not suitable for high-mix low-volume production. In addition, a special process is required to mold the hollow product, which complicates the production process. Further, as a matter of course, in the injection molding process, the foam layer cannot be provided inside. In the blow molding method, a parison (hollow cylindrical resin in a molten and softened state) is supplied between the molds, then the mold is clamped, and the fluid is pumped into the hollow parts to make the outer surface of the parison the molding surface of the mold. It is a method of pressing and transferring to. Since it is pressed by the pressure of the fluid, it is relatively low pressure (4-10kg
/ Cm ² ), therefore, the molding surface is not properly transferred, which is unsuitable 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 products. JP-A-7-195535 discloses that
A blow-molded hollow molded body is loaded into a mold that can be opened and closed and has a cavity having substantially the same shape as that of the hollow molded body. Then, the mold is slightly opened and foam beads are placed in the hollow molded body. There is disclosed a method for producing a foamed molded product, in which the mold is closed, the mold is then clamped, and heated steam is blown into the foamed product to carry out foam molding. Also disclosed is a manufacturing method in which foam beads are subsequently filled after blow molding to perform the above-mentioned foaming. Japanese Unexamined Patent Publication (Kokai) No. 58-102734 discloses a hollow molding die including a thin molding inner mold and a cooling outer mold capable of contacting / isolating from the molding inner mold. In this mold, the inner mold for heating is heated before the parison is supplied in order to improve the surface gloss of the hollow molded product.
After the parison is brought into contact with the molding surface of the molding inner die, the inner surface of the cooling outer die is brought into contact with the outer surface of the molding inner die to rapidly cool the molding inner die to obtain a molded product. ing. In Japanese Patent Laid-Open No. 4-77231, when the parison is brought into contact with the molding surface of the molding die for molding, the temperature of the molding die is set between the temperature near the crystallization rate of the parison and the melting point. By holding it, it is possible to prevent die lines and weld lines from remaining on the surface of the molded product.
A blow molding method is disclosed in which a refrigerant is circulated in a hollow portion of a parison during molding to prevent a molding cycle time from being lengthened. Japanese Examination 6-73
No. 903, a lid having good heat conductivity and having a large number of conducting holes is fixed to a container-shaped die frame, and a die surface area including the lid and an intermediate layer behind the die surface area. There is disclosed a molding die which is formed and is filled with a resin or metal having a low heat transfer property in the intermediate layer or provided with a reinforcing rib having a through hole.

[0003]

[Problems to be Solved by the Invention] Having a mirror surface and a grain surface,
In addition, there is a demand to manufacture a resin molded product having a foamed portion inside by using a mold having a relatively simple structure and in a short cycle time by a relatively simple process. In the manufacturing method disclosed in Japanese Patent Laid-Open No. 7-195535, there is no mention of a blow molding method for manufacturing a mirror surface or a grain surface on the outer surface. JP-A-58-1
In the hollow molding die of Japanese Patent No. 02734, the molding surface is beautifully transferred by heating the molding inner die, but the molding inner die is displaced relative to the cooling outer die and brought into contact with it. Since the resin is cooled by, the structure of the mold may be complicated and weakened, and the cooling time becomes long. Further, there is no mention of forming a foamed portion inside the molded product at the time of molding. JP-A-4-77
In the blow molding method of Japanese Patent No. 231, the molding surface is cleaned by heating and holding the temperature of the molding die at the above temperature, but the cooling time is shortened because the heating surface is kept heated even at the cooling time. The effect is not so great. Further, since the parison is cooled from the inside by circulating the refrigerant, the temperature control for heating and maintaining the temperature of the molding die at the above temperature becomes complicated. Further, there is no mention of forming a foamed portion inside the molded product at the time of molding. In the device of Japanese Patent Publication No. 6-73903, heating and cooling of the molding surface is performed by a lid body (mold surface area) on which the molding surface is formed.
The heating / cooling medium is passed through a large number of through holes provided inside or on the backside of the molding surface, and the heating / cooling medium is fed into the intermediate layer behind the molding surface. Since the heat transfer inside is slow, it is difficult to shorten the cycle time. Further, there is no mention of forming a foamed portion inside the molded product at the time of molding. The present invention has a good mirror surface or grain surface on the outer surface, and a resin molded article having a foamed portion inside, in a relatively simple process, and in a relatively short cycle time,
It is intended for blow molding.

[0004]

The invention of claim 1 uses a thermoplastic resin having a longitudinal elastic modulus at (Vicat softening temperature (T) +100) ° C. of 0.01 to 10 [kg / cm ² ]. The parison that has been formed is supplied to the molding surface of the mold, and the outer surface side of the parison is pressed against the molding surface with a pressure of 100 [kg / cm ² ] or less to be in close contact and provided on the back surface side of the molding surface. While heating the molding surface from the back surface side by the heating means to raise the temperature to Vicat softening temperature (T) ° C. or higher,
Using this heat, the foaming component in the parison is foamed, and the molding surface is (Vicat softening temperature (T) -10) ° C.
It is a blow molding method in which a molded product is obtained by cooling to the following temperature. That is, by heating and cooling as described above, the outer surface is molded so as to have a mirror surface or a textured surface, and as described above, the resin is foamed in the hollow of the parison to form a foam layer inside. To be molded. The heating may be performed by providing a space on the back surface side and supplying a heating fluid to the space, as in claim 5. Further, as in claim 6, the space on the back surface side may be divided into a plurality of spaces, and the heating fluid may be supplied to a desired divided space to heat the portion of the molding surface corresponding to the divided space. .

According to a second aspect of the invention, the longitudinal elastic modulus at (Vicat softening temperature (T) +100) ° C. is 0.01 to 1
A parison using 0 [kg / cm ² ] of a thermoplastic resin is supplied to the molding surface of the mold, and a heating fluid is supplied to the inside of the parison to foam the foaming component in the parison and The pressure inside the parison causes the outer surface side of the parison to be pressed against the molding surface at a pressure of 100 [kg / cm ² ] or less to bring it into close contact, and the molding surface is (Vicat softening temperature (T) -10) ° C. or less. It is a blow molding method in which a molded product is obtained by cooling to the temperature. That is, supplying heating fluid,
In addition, by cooling as described above, the outer surface is molded so as to have a mirror surface or a textured surface. Further, the heat of the heating fluid causes the resin to foam inside the parison hollow to form a foam layer inside. Further, the outer surface of the parison is pressed against the molding surface by the pressure of the heating fluid and / or the pressure of the foaming. In addition to the heating by the heating fluid, the heating may be performed from the back surface side of the molding surface as in claim 4. The heating may be performed by providing a space on the back surface side and supplying a heating fluid to the space, as in claim 5. Further, as in claim 6, the space on the back surface side may be divided into a plurality of spaces, and the heating fluid may be supplied to a desired divided space to heat the portion of the molding surface corresponding to the divided space. .

According to a third aspect of the invention, the longitudinal elastic modulus at (Vicat softening temperature (T) +100) ° C. is 0.01 to 1
A parison using a thermoplastic resin of 0 [kg / cm ² ] is supplied to the molding surface of the mold to foam the foaming component in the parison,
At least the parison is pressed from inside the hollow by the pressure of the foaming to press the outer surface side against the molding surface with a pressure of 100 [kg / cm ² ] or less to bring the molding surface into close contact with the molding surface (Vicat softening temperature ( T) is a blow molding method in which a molded product is obtained by cooling to a temperature of -10) C or lower. That is, the outer surface of the parison is pressed against the molding surface by the foaming pressure to mold the parison. The foaming is performed, for example, by supplying a heating fluid into the parison, reacting the foamed resin, or heating the parison from the outside. By the heat and the cooling as described above, the outer surface is formed into a mirror surface or a textured surface. Note that, as in claim 4, heating may be performed from the back surface side of the molding surface. The heating may be performed by providing a space on the back surface side and supplying a heating fluid to the space, as in claim 5. Further, as in claim 6, the space on the back surface side may be divided into a plurality of spaces, and the heating fluid may be supplied to a desired divided space to heat the portion of the molding surface corresponding to the divided space. .

According to a seventh aspect of the present invention, in any one of the first to sixth aspects, pressing is performed with a resin film interposed between the molding surface of the mold and the outer surface of the parison. Is a blow molding method in which a molded product having the resin film layer on the outer surface is obtained by closely adhering the resin film. That is,
As described above, a molded product having a film layer on the outer surface can be obtained by forming a mirror surface or grain surface on the outer surface, forming a foam layer inside and interposing a film as described above.

The invention of claim 8 has a longitudinal elastic modulus of 0.01 to 1 at (Vicat softening temperature (T) +100) ° C.
A parison using 0 [kg / cm ² ] of a thermoplastic resin is supplied to the molding surface of the mold, and heating fluid is supplied to the space on the back surface side of the molding surface to heat the molding surface from the back surface side. To raise the Vicat softening temperature (T) ° C. or higher to foam the foaming component in the parison so that one of the pressure in the parison and the pressure of the heating fluid follows the other pressure. Then, the outer surface of the parison is pressed against the molding surface with a pressure of 100 [kg / cm ² ] or less so that the parison is brought into close contact with the molding surface.
0) A blow molding method in which a molded product is obtained by cooling to a temperature of 0 ° C or lower. The pressure of the heating fluid introduced into the space on the back side of the molding surface and the pressure in the parison (the pressure of foaming, the pressure of the heating fluid and the pressure of foaming when foaming by supplying the heating fluid into the hollow) In order to make one follow the other, the space on the back side of the molding surface and the internal space of the parison may be communicated with each other via a check valve or the like, or the pressure in both spaces may be adjusted. The pressure in both spaces may be synchronized using a piston that is displaced accordingly.
The invention of claim 9 is the blow molding method according to any one of claims 1 to 8, wherein the parison is a foaming component composed of a foaming agent and the thermoplastic resin. Claim 10
The invention of No. 1 is the blow molding method according to any one of claims 1 to 8, wherein the resin in the foaming component is a resin of the same system as the parison. Foaming By making the resin in the foaming component and the parison the same type of resin, it is easy to recycle the molded product.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

Foaming component The foaming component used in the present invention comprises a foaming agent alone or a foaming agent and a resin. The foaming agent alone is used to foam a part of the parison. As the foaming agent, a physical foaming agent or a chemical foaming agent can be used. As the physical foaming agent, for example, inorganic materials such as air, carbon dioxide gas and nitrogen gas, and organic materials such as butane, pentane, hexane and freon can be used. Examples of the chemical foaming agent include inorganic systems such as sodium bicarbonate, bicarbonate, and carbonate, and examples of the organic system include isocyanate compound, azo compound, hydrazine derivative, semicarbazide compound, azide compound, Examples include nitroso compounds and triazole compounds. Examples of the resin include thermosetting resin and thermoplastic resin. Examples of the thermosetting resin include phenol resin, urea resin, epoxy resin, polyurethane and the like, with polyurethane being preferable. Examples of the thermoplastic resin include styrene resins (polystyrene, AB
S resin, etc.), polyethylene, polypropylene, vinyl chloride resin, cellulose acetate, acrylic resin, fluororesin, polyester, polyamide, polycarbonate and the like, and preferably styrene resin. The above-mentioned resin may not be injected into the parison, but may be resin-like after injection. The step of supplying (injecting) the foaming component to the parison includes: (1) a method of injecting into the parison after the parison is formed. (2) A method of injecting into a parison sealed in a mold. (3) A method of injecting into a parison after being in close contact with the molding surface. And the like. The method of injecting the foaming component is as follows: (1) A method of injecting the foaming component into the parison hollow portion by providing a hole that penetrates from the parison surface to the hollow portion with an injection needle from the parison surface side. (2) Injection method from inside parison molding die. (3) A method using a blowing device for bringing a parison into close contact with a molding surface. (4) Method using a device for supplying a heating fluid. And the like. The foaming inside the parison includes, for example, the following methods, and if necessary, these methods are combined to foam. That is, (1) the molding surface is heated by the heating means to raise the temperature to the Vicat softening temperature (T) ° C. or higher, and the heat is used to foam. (2) Foaming is performed by supplying a heating fluid into the hollow space of the parison. (3) Foaming is performed by the reaction of the foaming component. And so on.

Parison The method of hanging the parison is well known, and the description thereof is omitted. Examples of the material of the parison used in the present invention include AS resin, polystyrene, high-impact polystyrene, acrylonitrile-butadiene rubber-styrene graft copolymer (ABS resin), acrylonitrile-butadiene rubber-styrene-α-methyl. Graft copolymer made of styrene (heat resistant ABS resin), acrylonitrile-ethylene-propylene rubber-styrene and / or graft copolymer made of methyl methacrylate (AES resin), acrylonitrile-hydrogenated diene rubber-styrene and / Or a graft copolymer composed of methyl methacrylate, acrylonitrile-silicone rubber-
Graft copolymer consisting of styrene and / or methyl methacrylate, polyethylene, polypropylene, polycarbonate
Bonnet, polyphenylene ether, polyoxymethylene, nylon, methyl methacrylate-based polymer, polyether
Tersulfone, polyarylate, vinyl chloride, maleimide compound-styrene and / or acrylonitrile and / or
Or a copolymer comprising α-methylstyrene; a rubbery polymer; a maleimide compound; a graft copolymer comprising styrene and / or acrylonitrile and / or methyl methacrylate and / or α-methylstyrene; and a composite thereof. And resins obtained by adding a filler to these.

Further, according to the present invention, the molded article preferably molded to have a foamed layer inside is, for example, a housing, a sports product, a playground equipment, a vehicle product, a furniture product, a sanitary product, a building material. There are products and kitchen products, and the molded product has a foam layer in the hollow portion, the molded product is manufactured by a multi-layer blow molding method, and the molded product is plated, sputtered, vapor deposited, painted. There are molded products. Specific examples of these molded products include housings such as cooler boxes, TVs, and
There are audio equipment, printers, fax machines, copying machines, game machines, washing machines, air conditioners, refrigerators, vacuum cleaners, attach cases, musical instrument cases, tool boxes, containers, camera cases, and the like. Examples of sports products include swimming boards, surfboards, windsurfing, skiing,
There are snowboards, skateboards, ice hockey sticks, curling balls, gateball rackets, tennis rackets, canoes and boats. As playground equipment,
For example, there are bats, blocks, blocks, fishing tackle cases, pachinko underframes, and the like. Examples of vehicle products include air spoilers, doors, bumpers, fenders, bonnets, sunroofs, rear gates, wheel caps, instrument panels, glove boxes, console boxes, armrests, headrests, fuel tanks, driver's seat covers,
There are trunk tool boxes, etc. As furniture products,
For example, drawer, desk top plate, bed top plate / bottom plate, mirror stand frame plate, barbed box plate / front door, chair back plate / bottom plate, tray / tray, umbrella stand, vase, medicine box, hanger, cosmetic box, storage box board , Book stand, office desk top plate, OA desk top plate, OA rack, etc. Examples of sanitary products include shower heads, toilet seats, toilet plates, drain pans, water tank lids, vanity doors, and bathroom doors. Examples of building material products include ceiling boards, floor boards, wall boards, window frames, doors, and benches. Examples of kitchen products include cutting boards and kitchen doors. Examples of the molded product having the foam layer in the hollow part include a front door of a refrigerator and a cooler box. Examples of the molded product manufactured by the multi-layer blow molding method include a fuel tank. Examples of the molded, plated, sputtered, vapor-deposited, and painted products include vehicle exterior parts and electronic device hangs. It should be noted that these are merely examples, and molded products other than these can be suitably molded.

Means for heating the molding surface from the back surface side to raise the temperature to the Vicat softening temperature (T) ° C. or higher includes, for example, a space provided on the back surface side of the molding surface, and heating steam is supplied into the space to supply the above-mentioned steam. It can be realized by a mechanism that ejects toward the back surface.
The means for cooling the molding surface to (Vicat softening temperature (T) -10) ° C. is a mechanism for supplying a cooling medium (cooling water or cooling air) to the space provided for the heating means and injecting it toward the back surface. Can be realized by In addition, the space is divided by partition walls so that each divided space has a part of the back surface of the molding surface as an inner wall surface, and the heating medium or the cooling medium is supplied to any divided space as described above to divide the divided space. By jetting toward the back surface of the molding surface, it is possible to intensively heat or cool the portion of the molding surface corresponding to the back surface. In that case, there is an effect that the surface of the molded product corresponding to the heated and / or cooled molding surface can be finished differently from other surfaces. Further, a heating medium may be supplied to all the divided spaces for heating, or a cooling medium may be supplied to all the divided spaces for cooling. In that case, the entire back surface of the molding surface is quickly and uniformly heated or cooled. As a result, the textured surface and the mirror surface are uniformly and satisfactorily transferred onto the entire surface of the molded product, and defects such as uneven gloss can be prevented. When a mechanism for injecting high-pressure heated steam is used as the heating means, the heated steam is injected into a certain divided space Ba and the heated steam is not injected into another certain divided space Bb. When controlling, divided space Ba and divided space Bb
Since there is a pressure difference between the two, the partition wall must be able to withstand this pressure difference. The partition wall satisfying such a requirement can be realized, for example, as a structure in which a heat insulating plate made of the above-mentioned material is sandwiched between two metal plates.

With respect to the pressure in the space on the back side of the molding surface and the pressure in the parison, a mechanism for making one follow the other makes the pressure in the parison follow the pressure of the fluid supplied to the space on the back side of the molding surface. Alternatively, the pressure of the fluid supplied to the space on the rear surface side of the molding surface may be made to follow the pressure in the parison on the front side of the molding surface. In the former case, there is generally an advantage that the mechanism can be simplified. The reason is that it is necessary to continuously supply steam to the space on the back side for heating, and therefore,
Since it takes a relatively long time to raise the pressure in the space to a desired pressure, the parison is sealed, so that the desired pressure can be raised in a relatively short time. is there. Such a pressure adjusting mechanism can be configured, for example, by connecting the space on the back surface side of the molding surface and the inside of the parison. At that time, a check valve may be provided so as to prevent the steam for space heating on the back surface side from entering into the hollow of the parison. Further, instead of the above-mentioned communication, a pipe passage for supplying a fluid to the molding surface side and the internal space of the parison are connected via a cylinder displaceably provided with a piston balanced by the pressure of both spaces. By doing so, the pressure in both spaces can be made to follow.

First Specific Example (FIGS. 1 to 2 and 3) FIGS. 1 to 2 (a) to (d) show a molding method of the first specific example of the present invention. Further, FIG. 3 shows the timing of the molding method of FIGS. The mold whose longitudinal cross section is schematically shown in FIGS. 1 and 2 has a mold body 3 having a molding surface 30, and a mold body 4 supporting the mold body 3. Further, a space B is provided between the back side of the mold 3 and the mold body 4, and further,
A mechanism for injecting heating steam as a heating medium and cooling water or cooling air as a cooling medium into the space B (introduction valve 7
2, supply pipe 71, injection nozzle 70, discharge pipe 76, discharge valve 7
7) is provided. The mold body 3 and the mold body 4 are
Both are made of stainless steel.

A mechanism for supporting the mold body 3 by the mold body 4 is shown in FIG. That is, the supported plate 36 protruding around the mold body 3 is loosened by providing the play A in the groove 46 provided in the mold body 4 so as to correspond to the supported plate 36. The mold body 3 is inserted into the mold body.
Backed by 4. In addition, the groove 46 is the overhang portion 400a.
The main body plate 400 having the above is attached to the main body portion 401 with bolts 403. Further, as shown in FIG. 8A, at the corners of each of the four main body plates 400 arranged in a rectangular shape in a top view of the molding surface 30, the space between the adjacent main body plates 400 is approximately 0. A gap S of 1 [mm] is provided. 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. Therefore, even when the mold body 3 and the mold body 4 are thermally expanded by the heat during the molding of the molten resin and the relative displacement between the supported plate 36 and the groove 46 occurs, the displacement is caused by the play A. Is absorbed by, and adverse effects (bending, distortion, shortening of life of the mold 3, etc.) are prevented. Therefore, a precise molded product can be obtained. Also, the mold 3 has a longitudinal elastic modulus of 0.1.
Since it is supported by the mold body through the heat insulating layer 1 of phenol resin which is a material of × 10 ^{4 to} 100 × 10 ⁴ [kg / cm ² ], problems such as rattling are prevented.

The heat insulating layer 1 has a thermal conductivity of 0.0
01 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 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 × 1
It can be configured by using 0 ⁴ [kg / cm ² ]. The thermal conductivity is 0.001 to 1 [kcal / mh ° C], preferably 0.005 to 0.8 [kcal / mh ° C], and more preferably 0.01 to 0.5 [kcal / mh ° C]. And a longitudinal elastic modulus 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 It is also possible to form a laminated structure using a material of × 10 ^{4 to} 20 × 10 ⁴ [kg / cm ² ]. That is, the mold body 3 and the mold body 4 can be supported in a heat-insulated state, and the mold body 3 is rattled by the mold body 4 against the pressing force applied from the mold body 3 side to the mold body 4 side. It is enough if it can be supported without fail.
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 [kcal /
This is because if it is less than mh ° C], a special material is required and it is not practical, and if it exceeds 1 [kcal / mh ° C], the desired heat insulating effect cannot be obtained. Further, the reason why the above range is shown as the longitudinal elastic modulus of the heat insulating support member is that when the longitudinal elastic modulus is less than 0.1 × 10 ⁴ [kg / cm ² ], the rigidity is insufficient and the sealing is sufficient. This is because the heat insulating support portion becomes difficult to process if it exceeds 100 × 10 ⁴ [kg / cm ² ]. Materials having a thermal conductivity of 0.001 to 1 [kcal / mh ° C.] and a longitudinal elastic modulus of 0.1 × 10 ^{4 to} 100 × 10 ⁴ [kg / cm ² ] include, for example, polyarylate and polyether. Ether ketone, polyphenylene oxide, modified polyphenylene oxide, polyamide, acetal resin, tetrafluoroethylene resin, ceramics, PC, phenol resin,
Examples include urea, melamine, glass and unsaturated polyester. Phenol resin, urea resin, melamine and unsaturated polyester are preferable, and phenol resin is more preferable.

In the die used in this example, the space B formed between the back side of the die body 3 and the die body 4 is the O.
Since it is sealed from the outside by the ring 9, the heated steam injected into the space B during heating and the (cooling water + air) injected into the space B during cooling are connected to the mold body 3 and the mold body 4 ( The part where the mold 3 is supported by the mold 4 = supported plate
Leakage from the portion (36 and groove 46), a decrease in pressure in the space B that occurs in that case, and a bending of the molding surface 30 caused by the decrease are prevented. In the above space B, the valve 7
2, heating steam and cooling water + air are supplied through the pipe 71 and the nozzle 70. In addition, the corners of the space B are rounded to avoid concentration of pressure. Further, the heating steam / air / cooling water injected into the space B is
From the pipes 76 which are respectively communicated with the lower part of the space B, they are discharged through the valve 77. Further, in the mold used in this example,
On the inner surface of the mold body 4 exposed in the space B, as shown in FIG. 8B, a phenol resin layer having a thickness of 10 [mm] is formed.
Since the heat insulating layer (heat insulating member) 2 including the asbestos layer 21 having a thickness of 22 [mm] is provided, the heat in the space B is applied to the mold body.
Problems such as escape through the mold 4 and transfer of external heat to the space B through the mold body 4 are prevented. Therefore, the temperature drop of the heating steam and the heating oil supplied into the space B is prevented, and the transferability and dimensional stability of the molding surface are improved. The material of the heat insulating layer 2 is, for example,
Polyarylate, polyetheretherketone, polyphenylene oxide, modified polyphenylene oxide,
Polyamide, acetal resin, tetrafluoroethylene resin, ceramics, PC, phenol resin, urea, melamine, glass, unsaturated polyester, etc., asbestos,
Rigid urethane foam, rock wool, glass wool,
Calcium silicate, polystyrene foam, water repellent perlite, cork, wood (cedar), rubber, quartz glass, expanded beads, and the like, and combinations of two or more thereof can be used. Phenol resin, urea, melamine, unsaturated polyester, asbestos, rigid urethane foam and foam beads can be preferably used.

Next, the molding sequence in the first concrete example using the above-mentioned mold will be described. First, (a) and (b) of FIG.
As described above, the parison P is hung between the molding surface 30 and the molding surface 30 to seal the hollow portion, and then the air is supplied from the air supply source 90 to inflate the parison P to the molding surface 30. The outer surface is pressed and the foaming component (polyurethane foaming component) P1 is supplied from the foaming component supply source 91. Further, heated steam is jetted from the nozzle 70 into the space B on the molding surface back surface 31 side. As a result, the parison P is heated to the Vicat softening temperature (T) ° C. or higher, and
The foaming component P1 in the hollow of the parison P foams and spreads throughout the hollow of the parison P, as shown in FIG. Next, the heated steam in the space B is discharged from the discharge pipe 76 and the discharge valve.
While being discharged through 77, cooling water + cooling air is jetted into the space B through the nozzle 70. As a result, the parison P is rapidly cooled to (Vicat softening temperature (T) -10) ° C or lower. Further, after cooling, the mold is opened and a molded product (a molded product having a mirror surface or grain surface and a foamed layer inside) is taken out.

Second Specific Example (FIGS. 4 to 5 and 6) FIGS. 4 to 5 (a) to (d) show a molding method according to a second specific example of the present invention. Further, FIG. 6 shows the timing of the molding method of FIGS. The mechanism of the mold whose vertical cross sections are schematically shown in FIGS. 4 to 5 is basically the same as that of the mold shown in FIGS. In this specific example, unlike the molding method shown in FIGS. 1 and 2, air is not supplied into the parison P,
The parison P is pressed against the molding surface 30 by the pressure of the foaming component (polyurethane foaming component) P1 supplied into the hollow of the parison P. The molding process of the second specific example will be described below. First, as shown in (a) and (b) of FIG.
The parison P is hung between the molding surface 30 and the molding surface 30 to seal the hollow portion, and then the foaming component (polyurethane foaming component) P1 is supplied from the foaming resin supply source 91. further,
The heated steam is jetted from the nozzle 70 into the space B on the rear surface 31 side of the molding surface. As a result, the parison P is heated to the Vicat softening temperature (T) ° C. or higher, and the foaming component P1 inside the hollow of the parison P foams, and the pressure presses the outer surface of the parison P against the molding surface 30. That is, FIG.
As shown in (c) of FIG. 5, the parison P is spread over the entire hollow and the outer surface of the parison P is pressed against the molding surface 30. The foaming here may be foaming by heating from the back surface 31 side of the molding surface, or foaming by reaction of the foaming component P1. Next, the heated steam in the space B is discharged through the discharge pipe 76 and the discharge valve 77, and the cooling water + cooling air is discharged through the nozzle 70.
It is injected into the space B via. As a result, the parison P is rapidly cooled to (Vicat softening temperature (T) -10) ° C or lower. Further, after cooling, the mold is opened and a molded product (a molded product having a mirror surface or grain surface and a foamed layer inside) is taken out.

Mold having a mechanism different from the above (FIG. 7) FIGS. 7A and 7B are vertical sectional views of a mold used in the present invention different from FIGS. 1 and 2 and 4 to 5, respectively. It is a schematic diagram. The mechanism of the mold of FIGS. 7 (a) and 7 (b) is basically the same as that of FIGS. 1-2 and 4-5, and the mold body 3 having the molding surface 30 is A space B is secured on the back surface 31 side of 30 and is supported by the mold body 4. The mechanism for supporting the mold body 3 by the mold body 4 is shown in FIG. 8 similarly to the above-mentioned mold, and the description thereof is omitted. In the mold of FIG. 7 (a), steam supplied to the space B on the rear surface side of the molding surface 30 in the molds of FIGS. 1 to 2 is also supplied to the parison P on the molding surface side. Further, the communication pipe 71a is extended from the pipe 71, whereby the pressure in the parison P and the pressure in the space B are synchronized. The mold of FIG. 7 (b) is the same as the mold of FIGS. 1 and 2, and a communication pipe 71a extended from a pipe 71 for supplying steam to the space B on the back side of the molding surface 30 and a molding pipe 71a. Piping connected to piping 90a that supplies air into the parison P on the surface side
By inserting a cylinder 57 equipped with a piston 57a between 90b and 90b, the pressure in the pipe 90a and the pressure in the pipe 71a are synchronized, whereby the pressure in the space B and the pressure in the parison P are synchronized. It is to synchronize with.

Mold having a mechanism different from the above (FIG. 9) FIG. 9 is a schematic vertical sectional view of a mold used in the present invention, which is different from FIGS. 1 to 2, 4 to 5, and 7. 9B is a sectional view taken along the line BB in FIG. 9A, the piping system is drawn for easy understanding and is not necessarily in the same section. The mechanism of the mold shown in FIG. 9 is basically the same as each of the above-mentioned molds, and the mold body 3 having the molding surface 30 is
Secure the space B on the back side 31 side of 30
It is composed by supporting by 4. In addition, type 3
The mechanism for supporting the mold body 4 with the mold body 4 is shown in FIG. In the mold of FIG. 9, a space B (divided spaces Ba, Bb) divided into two is provided between the back surface side of the mold 3 and the mold body 4, and each divided space Ba, Bb is provided in each divided space Ba, Bb. A mechanism for independently injecting heated steam as a heating medium and cooling water or cooling air as a cooling medium is provided. That is, the divided space Ba is supplied with heating steam or cooling water + air through the valve 72a, the pipe 71a, and the nozzle 70a, and the divided space Bb is heated through the valve 72b, the pipe 71b, and the nozzle 70b. Cooling water is supplied. Further, the valves 72a and 72b are controlled to open and close independently. That is, it is possible to supply the heated steam to only one of the divided spaces Ba or Bb. Also,
The corners of each divided space are rounded to avoid pressure concentration. In addition, the heating steam / air / cooling water injected into the divided spaces Ba and / or the divided spaces Bb is connected to the lower portions of the divided spaces Ba and Bb, respectively.
From 76, it is discharged through valve 77. Further, in the mold of FIG. 9, the dividing space Ba and the dividing space Bb are separated by the partition wall C. The partition wall C has a thickness of 1 mm, which is a heat insulating material, between two metal (stainless steel) plates each having a thickness of 5 mm.
It is composed by sandwiching 0 [mm] phenol resin plates. That is, by using a metal plate so that it can withstand the pressure difference between the divided spaces Ba or the divided space Bb when heated steam is injected into only one of the divided spaces Bb, and by using a heat insulating material, the divided space Ba or The loss of heat quantity when the heated steam is injected into only one of the divided spaces Bb is prevented. As the heat insulating material used for the heat insulating layer which is the inner layer of the partition wall C, the same material as the heat insulating layer 1 can be used.
The division of the space B shown in FIG. 9 can be naturally applied to each of the above-mentioned molds.

Further, in FIG. 9, the outer surface of the parison P and
By forming the film F between the molding surface 30 and the molding surface 30, a foamed layer is formed inside the molding as described above, and at the same time, a mirror surface or a textured surface is formed on the outer surface of the molding. A film layer for protection (a peelable film layer),
It is shown that a film (eg, a film having a pattern) layer for enhancing the design can be added. Film F
As, for example, low-density polyethylene film, medium-density polyethylene film, high-density polyethylene film, polypropylene film, lacquer-type moisture-proof cellophane, polymer-type moisture-proof cellophane, polyethylene cellophane, acetate film, soft polyvinyl chloride film, There are hard polyvinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, polystyrene film, polyester film, rubber hydrochloride film and the like. The resin film F is, for example,
It is selected according to the type of parison. The resin film F is supplied so as to be interposed between the molding surface 30 and the outer surface of the parison P, as shown in FIG. 9, for example. That is,
It is fed from the upper roller and is supplied between the molding surface 30 and the parison P so as to be stretched between the lower roller and the roller. Also, the film F supplied in this way
Is pressed against the molding surface 30 by the pressure of the fluid supplied to the inside of the parison P. As described above, the provision of the film layer on the outer surface of the parison can be naturally applied to the above-mentioned molds and the specific examples using the molds.

[0023]

EXAMPLES In Examples 1 and 2 shown in FIGS. 1 to 6, ABS45A (manufactured by Japan Synthetic Rubber Co., Ltd./Vicat softening temperature 105 ° C./205) was used as the thermoplastic resin material.
The longitudinal elastic modulus at 0 ° C. is 0.3 [kg / cm ² ]), the polyurethane foaming component is used as the foaming component, and IPB-EP-55 (Ishikawajima Harima Heavy Industries Ltd.) is used as the blow molding machine. (Manufactured by the company) was used for blow molding. Molding conditions are as follows: Concrete Example 1 (1) Extruder temperature: 220 ° C (2) Mold clamping force: 15ton (3) Parison blowing pressure: 6kg / cm ² (4) Heating of molding surface 30 Injection from nozzles 70a, 70b Heating steam pressure: 6kg / cm ² Final temperature of the molding surface 30: 140-150 ℃ Heating and holding time of the molding surface 30: 10sec (5) Cooling of the molding surface 30 Spray from nozzles 70a, 70b (cooling water + air) Pressure: 6kg / cm ² Final cooling temperature of molding surface 30: 70 ° C Cooling holding time of molding surface 30: 60sec Total process time: 150sec Example 2 (1) Extruder temperature: 220 ° C (2) Clamping force: 15ton (3) heating the nozzle 70a of the molding surface 30, heating steam pressure injected from 70b: 6kg / cm ² forming surface 30 of the final reaching temperature: 140 to 150 ° C. molding surface 30 heated holding time: 10 sec (4) molding surface 30 cooling nozzles 70a, injected from 70b (cooling water + air) pressure: final cooling temperature of 6 kg / cm ² forming surface 30: 70 ° C. molding surface 30 Cooling retention time: 60 sec overall process time: a 150 sec. Molded product molded in this way (Example product)
And the molded products (comparative example products) molded without heating the molding surface 30 in specific example 1 and specific example 2, the surface glossiness of each example product of specific example 1 and specific example 2 is The product had a uniform 95% over the entire surface of the product, and the R at the corner was 0.5 or less, while the surface gloss of each comparative product was 20.
%, And R at the corner portion was 0.5 or more. As for the foamed state, it was uniformly foamed in the hollow part of the molded product. By injecting the foamed resin into the hollow part of the molded product, the thermal conductivity in the thickness direction of the molded product is 0.0278 kcal /
mh ° C, thermal conductivity of foamed resin alone 0.0227k
The result was comparable to that of cal / mh ° C.
That is, the transfer of the molding surface of the example product was better than that of the comparative product. The state of the foam layer was also good. The outside dimension of the mold: 460 (L) x 560 (W) x 720
(H) [mm] Molded product dimension: 120 (L) x 40 (W) x 480 (H) [mm]. Further, when a molded product having a foamed layer was similarly manufactured using the molds of FIGS. 7 and 9, a good molded product could be obtained.

[0024]

According to the present invention, a resin molded product having a good mirror surface or grain surface on the outer surface and a good foam layer on the inside can be manufactured in a relatively simple process and in a relatively short time. Blow molding was possible with the cycle time.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a part of a process of a first example of the present invention, which is executed in the order of (a) → (b).

FIG. 2 is an explanatory view showing the rest of the steps of the first example of the present invention, which are carried out in the order of (c) → (d).

FIG. 3 is a timing chart showing the steps shown in FIGS. 1 and 2.

FIG. 4 is an explanatory diagram showing a part of the process of the second embodiment of the present invention, which is performed in the order of (a) → (b).

FIG. 5 is an explanatory diagram showing the rest of the steps of the second example of the present invention, which are carried out in the order of (c) → (d).

FIG. 6 is a timing chart showing the steps shown in FIGS. 4 and 5.

FIG. 7 (a) and (b) are respectively the first and second aspects of the present invention.
Explanatory drawing which shows a part of process of the other specific example different from FIG.

FIG. 8 is an explanatory diagram of a corner portion of a mold used in each specific example of the present invention.

FIG. 9 is an explanatory view showing a part of the process of another specific example of the present invention, which is different from the specific examples of the first, second, and FIG. 7;

[Explanation of symbols]

 P Parison P1 Foaming component F film

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Fumio Kurihara 2-11-24 Tsukiji, Chuo-ku, Tokyo Japan Synthetic Rubber Co., Ltd.

Claims (10)

[Claims] 1. (Vicat softening temperature (T) +100) ° C.
A parison using a thermoplastic resin having a longitudinal elastic modulus of 0.01 to 10 [kg / cm ² ] is supplied to the molding surface of the mold, and the outer surface side of the parison is 100 [ kg/
cm ² ], while pressing and adhering with a pressure of less than or equal to, and heating the molding surface from the back surface side by heating means provided on the back surface side of the molding surface to raise the Vicat softening temperature (T) ° C or higher, A blow molding method in which a foaming component in the parison is foamed by using this heat, and the molding surface is cooled to a temperature of (Vicat softening temperature (T) -10) ° C. or less to obtain a molded product. 2. (Vicat softening temperature (T) +100) ° C.
By supplying a parison using a thermoplastic resin having a longitudinal elastic modulus of 0.01 to 10 [kg / cm ² ] to the molding surface of the mold, and supplying a heating fluid to the inside of the parison,
While foaming the foaming component in the parison, the pressure inside the parison causes the outer surface side of the parison to be pressed against the molding surface at a pressure of 100 [kg / cm ² ] or less to closely adhere to the molding surface. (Bicut softening temperature (T) -10) A blow molding method in which a molded product is obtained by cooling to a temperature of not higher than ° C. 3. (Vicat softening temperature (T) +100) ° C.
A parison using a thermoplastic resin having a longitudinal elastic modulus of 0.01 to 10 [kg / cm ² ] is supplied to the molding surface of the mold to foam the foaming component in the parison, and at least the foaming component The parison is pressed from the inside by a pressure to press the outer surface side of the parison against the molding surface at a pressure of 100 [kg / cm ² ] or less to bring the molding surface into close contact with the molding surface (Vicat softening temperature (T) -10). ) A blow molding method in which a molded product is obtained by cooling to a temperature of ℃ or less. 4. The method according to claim 2 or 3, wherein the molding surface is heated from the back surface side by a heating means provided on the back surface side of the molding surface to raise the temperature to a Vicat softening temperature (T) ° C. or higher. A blow molding method in which the cooling is performed after the cooling. 5. The blow according to claim 1 or 4, wherein the heating is performed by supplying a heating fluid into a space configured so that the back surface of the molding surface is a part of the inner wall. Molding method. 6. The method according to claim 5, wherein the space is divided into a plurality of divided spaces whose inner wall surface is a part of the back surface of the molding surface, and the heating fluid is supplied to a desired divided space. A blow molding method, wherein the heating is performed on a portion of the molding surface corresponding to the desired divided space. 7. The method according to claim 1, wherein a resin film is interposed between the molding surface of the mold and the outer surface of the parison to bring the resin film into close contact with each other. A blow molding method for obtaining a molded article having the resin film layer on the outer surface thereof. 8. (Vicat softening temperature (T) +100) ° C.
A parison using a thermoplastic resin having a longitudinal elastic modulus of 0.01 to 10 [kg / cm ² ] is supplied to the molding surface of the mold, and a heating fluid is supplied to the space on the back side of the molding surface. As a result, the molding surface is heated from the back surface side to raise the temperature to the Vicat softening temperature (T) ° C. or higher, and the foaming component in the parison is foamed to obtain the pressure within the parison and the pressure of the heating fluid. The outer surface of the parison is pressed to adhere to the molding surface at a pressure of 100 [kg / cm ² ] or less so that one pressure follows the other pressure, and the molding surface has a (Vicat softening temperature ( T) -10) A blow molding method in which a molded product is obtained by cooling to a temperature of 10 ° C or lower. 9. The blow molding method according to claim 1, wherein the parison is a foaming component composed of a foaming agent and the thermoplastic resin. 10. The blow molding method according to any one of claims 1 to 8, wherein the resin in the foaming component is a resin of the same system as the parison.