JPH0948063A - Lamination blow molding method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a bonding blow molding method capable of obtaining a smooth and high quality bonded blow molding product having excellent surface transferability and no step. A laminated blow molding method in which a resin sheet S is laminated to form a resin sheet S having a thickness of 1
The fine through-holes having a diameter of 0.1 mm to 1 mm and formed by punching are provided at 1 or more and 500 or less per 100 cm ² of area, and a convex shape generated as a return of the fine through-holes h. The projection 60 is made to face the mold surface, and the resin sheet S is interposed between the parison contact surface and the mold, and then the mold is closed by a heated mold, blown and cooled to mold.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bonding blow molding method for molding a molded product in which a resin sheet is bonded to the surface of a parison, and in particular, a high quality resin sheet bonded molded product having an excellent appearance is obtained. The present invention relates to a bonding blow molding method that can be performed.

[0002]

2. Description of the Related Art In blow molding for producing a hollow resin product from a parison injected or extruded into a cylindrical shape from a die head, a parison is injected or extruded from a die head, and a pre-blow is applied to a parison formed into a bag by a parison pinch. Line, inflate it slightly, put it in an open mold, close the mold, evacuate the gas in the cavity formed by the mold and the parison, and then vacuum pump the device through a small air vent hole to the mold surface Then, high-pressure air is blown into the parison to form the parison into a predetermined shape based on the cavity, and the parison is cooled with a mold to complete the molding. In this way, the molded resin product is opened and taken out. FIG. 6 shows a conventional blow molding machine. 6 shows a so-called side-feed type blow molding machine 1 in which molten resin is supplied from one side of the die head 2, and the high-temperature molten resin pressed by the injection device 4 is the resin supply port 2a. And passes through an annular passage provided between the die head 2 and the mandrel 3 and is discharged from the annular space passage 7 at the lowermost end to form a parison P. A passage 2b and a valve 5 (or plug) provided outside the passage 2b are disposed at a position 180 ° away from the resin supply port 2a of the die head 2. The core 3a is connected to the paricon rod 6a penetrating the mandrel 3 and is slightly moved up and down in the vertical direction by the operation of the paricon cylinder 6 to control the wall thickness of the parison P (gap). ) Can be adjusted.

On the other hand, a resin sheet is interposed between the parison discharged from the blow molding machine 1 and the mold cavity, the mold is clamped, and the resin sheet is bonded to the surface. The production of blow-molded articles has traditionally been practiced.

[0004]

However, in such a conventional bonded blow-molded product, the resin sheet is broken during the blow molding, or wrinkles are generated on the surface of the molded product, so that a smooth flat surface is not formed. There is a disadvantage that air is present between the resin sheet and the parison surface, and air remains on the surface of the molded article as air bubbles, and the resin sheet and the parison surface do not adhere to each other over the entire surface. Therefore,
A plurality of fine through holes are previously punched in the resin sheet to be bonded to the parison, and air is positively sucked from the inner surface of the mold after the mold is clamped. A method of discharging the intervening air to bring the two into close contact with each other is also conceivable, but in this case there was a problem that the traces of fine through-holes remained on the surface of the molded product after molding, impairing the appearance. Occurred in. In addition, the surface properties of the resin sheet of the conventional laminated blow-molded product are poor, and there is a drawback that the product value is low due to lack of gloss.

[0005]

In order to solve the above problems and obtain a high-quality bonded blow-molded product having no holes and smooth gloss, the first aspect of the present invention is used. In the invention, a resin sheet is attached to the outer surface of the parison discharged from the annular resin passage between the die head and the core attached to the lower end of the mandrel, and the parison is sandwiched by a pair of left and right molds to form a hollow product. A method for laminating blow molding, wherein the resin sheet is provided with 1 to 500 fine through holes having a diameter of 0.1 mm to 1 mm and formed by punching on the surface per 100 cm ² of area. , The convex projection generated as a return of the fine through hole at the time of punching the resin sheet is opposed to the mold cavity surface, and is sandwiched between the mold cavity surface and the parison surface to close the mold. Performs Rutotomoni blowing, after holding cooled as it was and to take out the molded product. Further, in the second invention, in the first invention, before the resin sheet is sandwiched between the mold cavity surface and the parison surface and the mold is closed, the resin sheet is preliminarily set at a softening point temperature of the resin sheet. It was decided to preheat to a higher temperature. Further, in the third invention, the first invention and the second invention
In the invention described above, the fine through holes of the resin sheet are arranged only in the regions that come into contact with the hollow portions of the parison. Then, in a fourth invention, in addition to the first to third inventions, an inorganic material such as a metal plate, a metal foil, a glass, a ceramic material, a stone material, or a leather or a paper is provided between the back surface of the resin sheet and the front surface of the parison. It was decided that molding should be performed with any of organic materials such as wood, or a combination thereof.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a resin sheet having a plurality of fine through-holes disposed on the surface between a discharged parison surface and a mold cavity surface is used as a back side when punching the fine through-holes. The convex projection generated as a result of the return to the mold surface is drooped in an extended state, the mold is closed, and the parison in which the resin sheet is blown on the mold cavity surface that has been heated for heat retention beforehand is inserted. It is possible to obtain an excellent bonded blow-molded product which is pressed by a high gloss. Then, when the resin sheet is preheated to the softening point temperature or higher and then the bonding and clamping are performed, the adhesion between the parison and the resin sheet is further improved, and the transferability is further improved. Further, it is possible to prevent the convex protrusions of the fine through-holes from being easily crushed and leaving a hole mark after closing the fine through-holes. Further, molded products having various designs and designs can be obtained by freely selecting the color of the resin sheet or adopting a resin sheet on which a decorative pattern or a decorative pattern is printed in advance. Further, between the back surface of the resin sheet and the front surface of the parison, an inorganic material such as a metal plate, a metal foil, glass, a ceramic material, a stone material, or an organic material such as leather, paper, wood, or a combination thereof is used. By interposing and molding, it is possible to obtain a further expanded product group.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 4 relate to an embodiment of the present invention, FIG. 1 is an overall vertical cross-sectional view of a blow molding machine, FIG. 2 is a perspective view of a blow molding machine, and FIG. 3 is a cross-sectional view showing a surface state of a bonded blow-molded product. 4 and 5 are enlarged cross-sectional views of the resin sheet before and after the bonding. 1 and 2, below the die head 2 of the blow molding machine 1, a pair of left and right molds 8,
8 is provided so as to be able to come into contact with and separate from the mold 8, and the resin sheet S is wound on the upper part of the die 8 at a position where the resin sheet S is hung down along the surface of the parison P discharged from the die head 2 and hung down. 20 is arranged via a roll base 22.
A roll base 22 is attached to the lower end of the roll 20, and a cutter 30 whose tip is formed by a sharp blade that horizontally moves back and forth in the parison direction by the operation of an air cylinder 30a is arranged in front of the cutter 30. A cutter seat 30b having a groove into which the cutting edge of the cutter 30 is fitted is provided, and the suspended resin sheet S can be cut at any time without damaging the surface of the parison P. Further, a sheet clip 24 for holding the lower end of the resin sheet S and holding the resin sheet S in a vertically extended state during operation is provided at the lower end portion of the mold 8.

On the other hand, a medium passage 8a for cooling the cavity surface of the die 8 is provided in a portion facing the cavity surface of the die 8.
Is connected to a medium supply device (not shown). Further, a plurality of vent holes 8b which penetrate the mold 8 from the cavity surface of the mold 8 at right angles to the cavity surface and discharge air are provided at appropriate intervals. Further, in order to positively suck the air discharged from these vent holes 8b, a collecting duct 10 is provided so as to cover the outside of the mold 8, and an exhaust pipe provided with a solenoid valve 12 and a suction fan 14 is provided. 11 are provided. Alternatively, the mold 8 is provided with a vent hole 8b.
Alternatively, a metal having a myriad of fine vents, ie, a porous metal, may be used.

The resin sheet S wound on the roll 20 is
In addition to the same type of resin as the parison P, a different type from the parison P may be used. The resin sheet S may be a multilayer resin sheet, a metal foil, paper, glass fiber or the like may be laminated between the sheets in a sandwich shape, or the sheet may be filled with an inorganic substance (glass fiber, inorganic mineral, etc.). . However, since the sheet material attached to the burr part may be crushed and reused for the next molding shot,
Basically, the same material as the parison P is desirable. The thickness of the resin sheet S is not preferably too thick because it is necessary to manufacture a laminated blow-molded product, and is usually 1 mm or less, but preferably 0.5 mm or less. If the resin sheet S is too thick, it is difficult to obtain a molded product that matches the cavity shape in the deep shape in which wrinkles easily occur.
In addition, the cooling time after molding becomes long and the productivity is lowered. Further, if it is too thin, the resin sheet S may be damaged during molding. On the surface of the resin sheet S, fine through holes h for discharging the air present between the parison P and the resin sheet S during press-molding with the parison P are arranged in a grid pattern as shown in FIG. Alternatively, a plurality of staggered arrangements may be provided. The diameter of the fine through hole h is 0.1 mm to 1 mm,
Preferably, it is about 0.1 mm or more and 0.3 mm or less,
The array density is at least 1 per 100 cm ^2, but preferably 4 or more per 100 cm ^{2 to} 500.
It is desirable to keep the number below. The reason is that it is difficult to discharge gas when the diameter of the fine through holes h is 0.1 mm or less,
This is because, if it is 0.3 mm or more, hole traces tend to remain after molding, and the lower limit of the array density (1 or more per 100 cm ² ) is determined by the minimum required gas discharge area, and the upper limit of the array density ( 500 or less per 100 cm ² ) is derived from the fact that the effect of gas discharge is the same even if a larger number is provided. However, when the elongated ribbon-shaped resin sheet S is locally attached to the surface of the parison P, the fine through holes h may be omitted (the intervening air deviates from the left and right ends of the ribbon-shaped resin sheet S). Therefore, the fine through hole h is not required intentionally).

The blowing pressure of the blowing after closing the mold completely eliminates the air between the surface of the parison P and the resin sheet S attached to the parison P, and the air remains between the two to leave the surface of the molded product. To prevent defects such as bubble formation,
The pressure is at least 4 kgf / cm ² .

The softening point temperature when preheating the resin sheet S is equal to the glass transition temperature in the case of the amorphous resin,
The BS resin has a temperature of 110 to 130 ° C, and the modified PPO resin has a temperature of 120 to 140 ° C. On the contrary,
In the case of a crystalline resin, a temperature between the crystallization temperature and the melting point is suitable, and in the case of PP, 130 ° C to 160 ° C, P
In case of E, 100 ° C to 130 ° C, in case of nylon 6, it is 18 ° C.
It becomes 0 to 230 ° C. Various oils, water, and pressurized water (steam) are used as a medium for controlling the temperature of the mold, and it is preferable to use the same substance having different temperatures. As a method of preheating the resin sheet S, a method of directly heating the surface with a light source or a heat source (for example, a halogen lamp, high frequency induction heating, an oven, etc.) from the outside can be adopted.

On the surface of the resin sheet S on which the parison comes into contact,
Allow the adhesive to be applied beforehand, or spray-apply an adhesive solution in the form of a spray, or
It is desirable to consider brushing so as to facilitate the bonding with the surface of the parison P during molding.

The operation of the blow molding method of the present invention in the blow molding machine 1 configured as described above will be described. First, while holding both molds 8 and 8 in the mold open state, the resin sheet S is wound down from the roll 20 and hung down, and the lower end is pinched by the sheet clip 24, and held in the vertically stretched state. Then, the parison P is discharged from the lower end of the die head 2 by an injection device or the like. . Next, the mold is closed, the upper end of the resin sheet S is horizontally cut by the cutter 30, and the parison P is molded while the resin sheet S is attached to the surface of the parison P. The resin sheet S is pressed against the cavity surface of the die and the cavity surface of the die is transferred, and the front surface of the parison and the back surface of the resin sheet are pressure-bonded together and joined by the pressurized air blown into the parison P via the blow pin. It

In the resin sheet S, if the fine through-holes h have no "return" at the time of punching as shown in FIG. 5, there is a hole mark on the surface of the molded product even after the bonding molding is carried out. However, there is a fear that the appearance will be spoiled. In order to improve this problem, in the present invention, the resin sheet S is formed by punching the fine through holes h by a punching method such as a pressing method. As a result, as shown in FIG. 4, the convex protrusion 60 is formed in one of the minute through holes h. When the surface on which the convex protrusions 60 are formed faces the mold surface and is then clamped by being interposed between the mold surface and the parison surface as described above, the convex shape of the fine through-hole h is formed. As a result of the projection 60 being pressed and crushed, the fine through holes h are closed and the traces of the holes disappear. When the resin sheet S is preheated to its softening point temperature or higher before molding, the "return" of drilling is also softened, so that the resin sheet S is easily pressed and crushed, and the disappearance of hole traces is further facilitated.

The resin sheet S used in the laminated blow-molded product of the present invention may be a normal commercial product produced by extrusion molding, but one side (blow-molded product surface side) may have a decorative pattern or a decorative pattern. If, for example, an ABS extruded sheet on which a decorative pattern is printed is used, various panel-shaped molded products having high gloss and arbitrary colors and patterns can be obtained. Its applications include daily necessities (chairs, TV stands, bookshelves, cabinets, system kitchens, blackboards, sheds, desk tops, piling tops, furniture doors, side panels, bathtubs, mirror stands, etc.) Home appliances (refrigerator doors, dishwashers) Doors, washing machine doors, washing machine side panels, TVs, speaker boxes, computer housings, etc. Automotive products (spoilers, glove box doors, instrument panels, rear partial shelves, door trims, side garnishes, console boxes, road floors, bumpers, fenders) There are trunk lids, motorcycle fenders, outer panels, etc.) Building materials (doors, wall materials, partition boards, partitions, etc.) Daily miscellaneous goods.

Further, as shown in FIG. 3, by embedding a metal foil 40 or the like on the inner surface of the resin sheet S on the parison side,
By connecting electric wires to the floor panel that can be heated or the metal foil 40, the applications of automobile-related parts such as a spoiler with a built-in antenna, a glove box door, and interior parts will be expanded. Further, by combining known techniques such as insert and foam molding, the usage can be further expanded. Resin sheet S
The plurality of fine through holes h provided in the
By making a punching hole with a small diameter of m or less and having a convex projection 60, a large number of pores remain on the surface of the product because it is automatically crushed from the surroundings and closed after the air is discharged by the blow pressure. Therefore, there is no problem that the quality is deteriorated.

[0017]

As described above, in the present invention,
The diameter formed by punching on the surface is 0.1 mm ~
1 mm or more and 500 or less 1 mm fine through-holes per 100 cm ² of area are provided, and the resin sheet having the convex protrusions generated as a return of the fine through-holes at the time of punching is used. The mold is closed by sandwiching it between the mold cavity surface and the parison surface while facing the mold cavity surface, and blowing is performed at the same time that the mold is placed on the surface of the resin sheet at a softening point temperature or higher. Since the resin sheet is heated to a temperature and the surface of the resin sheet is closely adhered to the parison, the resin sheet will not be damaged, and there will be no trace of holes on the surface. A laminated blow-molded product having excellent properties can be obtained. Further, by freely selecting the color of the resin sheet, it is possible to easily, easily and inexpensively produce a multi-color, multi-layer molded product without changing the color with a single-layer blow molding machine. Also,
By adopting a resin sheet with a decorative pattern and a decorative pattern as needed, the variety of designs and designs can be enjoyed. Furthermore, according to the method of the present invention, an excellent bonded blow-molded article having no step at the boundary between the end of the resin sheet and the surface of the parison can be obtained.

[Brief description of drawings]

FIG. 1 is an overall vertical sectional view of a blow molding machine according to an embodiment of the present invention.

FIG. 2 is a perspective view of a blow molding machine according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a surface state of a bonded blow-molded product according to an example of the present invention.

FIG. 4 is an enlarged cross-sectional view of a resin sheet before and after bonding in a blow molding method according to an example of the present invention.

FIG. 5 is an enlarged cross-sectional view of a resin sheet before and after bonding showing another embodiment of the blow molding method according to the embodiment of the present invention.

FIG. 6 is an overall vertical sectional view of a conventional blow molding machine.

[Explanation of reference numerals] 1 blow molding machine 2 die head 2a resin supply port 3 mandrel 3a core 4 injection device 5 valve 6 Parison cylinder 6a Parison rod 7 annular space passage 8 mold 8a medium passage 8b vent hole 10 assembly duct 11 exhaust Tube 12 Solenoid valve 14 Suction fan 20 Roll 22 Roll stand 24 Sheet clip 30 Cutter 30a Air cylinder 30b Cutter seat 40 Metal foil 50 Step 60 Convex projection P Parison S Resin sheet h Micro through hole

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Claims (4)

[Claims] 1. A hollow product is obtained by attaching a resin sheet to the outer surface of a parison discharged from an annular resin passage between a die head and a core attached to the lower end of a mandrel, and sandwiching the resin sheet with a pair of left and right dies. The method is a continuous blow molding method, wherein the resin sheet has fine through-holes having a diameter of 0.1 mm to 1 mm and an area of 100 cm.
Is one to 500 amino arranged per ^2, the resin sheet after that, and the convex projections that have occurred as the return of the fine through-hole during the punching of the resin sheet so as to face the mold cavity surface, the mold cavity surface And the surface of the parison, the mold is closed and blown, the molded product is taken out after holding and cooling as it is, and then the blow molding method. 2. The resin sheet is preheated to a softening point temperature of the resin sheet or higher before the resin sheet is sandwiched between the die cavity surface and the parison surface to close the die. 1. The method of laminating blow molding according to 1. 3. The bonding blow molding method according to claim 1 or 2, wherein the fine through holes of the resin sheet are provided only in a region that abuts the hollow portion of the parison. 4. An inorganic material such as a metal plate, a metal foil, glass, a ceramic material, a stone material, or an organic material such as leather, paper, wood, or the like between the back surface of the resin sheet and the front surface of the parison, or The bonding blow molding method according to claim 1, wherein the combination blow molding is performed by interposing a combination thereof.