JP2001001390A - Lamination blow molding method of fiber reinforced plastic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the subject lamination blow molding method capable of stably molding even fiber reinforced plastic high in fiber content without blowing out the same and capable of obtaining a blow molded product to which value added such as decorative properties, touch, cushioning properties is applied. SOLUTION: Fiber reinforced plastic is used as the resin material quality of a parison P and the hollow parison P extruded from a die is suspended to the space between a pair of left and right opened molds and a skin sheet S is interposed between the parison and one or both of a pair of the left and right molds and, after both molds are closed, a pressure fluid is blown in the parison P to pressurize and expand the parison P and the parison P and the skin sheet S are pressed to the surface of the cavity between the molds to be integrally laminated to be formed into a predetermined shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to laminating blow molding of fiber reinforced plastics. At the same time as blow molding, various kinds of skin sheets are laminated on the surface of a resin part of a molded product to provide decorativeness, touch feeling, cushioning. TECHNICAL FIELD The present invention relates to a method for laminating blow-molded fiber-reinforced plastics, which can obtain a blow-molded article having added value such as properties and can stably mold a blow-molded article having excellent rigidity.

[0002]

2. Description of the Related Art When a fiber-reinforced plastic is used as a resin material of a parison for the purpose of obtaining a blow molded article having excellent rigidity, the higher the fiber content, the smaller the elongation of the parison. The parison was broken at the corner of the molded article where the ratio became large, so-called blowout occurred, and a good product could not be obtained. For this reason, fiber-reinforced plastics can be applied only to blow-molded articles having a low blow ratio, and when the parison resin material is long-fiber-reinforced plastic, the fiber content is 10% or less, which is the limit of blow molding. However, a blow molded product having the expected rigidity could not be obtained. In addition, since the blow pressure is low as in general blow molding, the surface of the blow molded product using fiber reinforced plastic has a higher feeling of touch and decorativeness as the fiber content is higher than that of plastic without fiber reinforcement. However, there is a problem that the range of application is limited from the viewpoint of the surface properties of the blow molded product.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and uses a fiber-reinforced plastic having a high fiber content which could not be conventionally applied to blow molding. Even if a molded product having the same shape as the blow molded product is molded, it can be molded stably without blowing out, and at the same time as the blow molding, various skin sheets are attached to the surface of the molded product resin part, and decorativeness, touch feeling, cushioning properties, etc. It is intended to provide a laminated blow molding method capable of obtaining a blow molded product having the added value of (1).

[0004]

In order to solve the above-mentioned problems, a first aspect of the present invention is a lamination blow molding method using a fiber-reinforced plastic as a resin material of a parison, which is extruded from a die. Drop the hollow parison between the pair of left and right molds that have been opened,
After interposing a skin sheet between the parison and one or both of the pair of left and right molds, the molds are closed, and a pressurized fluid is blown into the parison to pressurize the parison. By inflating and pressing the parison and the skin sheet against the cavity surface of the mold, the skin sheet and the parison are integrally bonded and shaped into a predetermined shape. In the second invention mainly based on the first invention, a long fiber reinforced plastic having a fiber length of 3 to 10 mm is used as the resin material of the parison.

[0005]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a vertical sectional view of a main part of a lamination blow molding machine according to an embodiment of the present invention.

As shown in FIG. 1, a pair of left and right molds 8 are provided below a die head 2 of a lamination blow molding machine 1.
8 is disposed so as to be able to freely contact and separate, and the tip of the hollow parison P discharged from the die head 2 is sandwiched by a parison pinch (not shown) and fused to form a bag.
The parison P is suspended while slightly inflating by putting compressed air into the inside of the mold, and is sandwiched between a pair of left and right molds 8, 8. Further, the skin sheet S to be bonded to the parison P is prepared in a state of being wound on a roll 20, and the roll 20 is attached to a roll base 22 provided above the mold 8. After the molds 8, 8 are opened, the lower end of the skin sheet S unwound from the roll 20 is gripped by a sheet clip 24 disposed below the mold 8, and the molds are opened. It is configured to hold the skin sheet S suspended between the dies 8, 8 in an extended state. Further, a cutter 30 is disposed on the roll base 22 via the air cylinder 30a between the mold 8 and the roll 20 on the surface side of the suspended skin sheet S,
A cutter receiving seat 30b having a horizontal groove into which the cutting edge of the cutter 30 is fitted is fixedly provided at a position facing the cutter 30 on the back surface side of the hanging skin sheet S.

On the other hand, a medium passage 8a for heating or cooling the mold 8 is formed in the mold 8 so that a heat medium or a coolant whose temperature is adjusted by a medium circulation device (not shown) is circulated through the medium passage 8a. Is configured. Further, a plurality of vent holes 8b penetrating the mold 8 are formed in the cavity surface of the mold 8 at an appropriate interval, and air existing on the cavity surface side of the mold 8 during lamination blow molding. Collects a duct 10, an exhaust pipe 11, a solenoid valve 13,
And it is constituted so that it may be forcibly exhausted out of the mold 8 via the suction fan. The laminating blow molding machine 1 shown in FIG. 1 is configured to hold the skin sheet S in an extended state only on one side of the parison P. A mechanism for cutting S may be provided on both sides of the parison P.

In order to obtain a blow-molded article having excellent rigidity and the like, in blow molding using a fiber-reinforced plastic, particularly a long-fiber-reinforced plastic as a resin material of the parison, a pair of left and right molds is used in a normal blow molding method. When the parison P is sandwiched between the molds 8 and 8, the surface portion of the parison P which is in contact with the mold 8 is rapidly cooled, and blow-out occurs so that the parison P is torn from this portion, so that stable blow molding cannot be performed. On the other hand, in the method for laminating and blowing the fiber-reinforced plastic according to the present invention, the parison P is sandwiched between the pair of left and right molds 8 and 8 via the skin sheet S, so that the skin sheet S functions as a heat insulating material and Since the cooling rate of P is moderated and the parison P reinforced by the skin sheet S is uniformly expanded throughout without being locally stretched, blow-out is prevented and good blow molding is performed. .

[0009] As needs along with the improvement of rigidity, decorativeness,
There is a strong demand for high-value-added blow-molded products with improved surface properties such as touch feeling and cushioning properties. In recent years, various types of skin sheets for bonding having various functions have become available in a wide variety. Was. Since the effect of preventing the occurrence of blowout according to the present invention is exerted regardless of the type of the skin sheet S, the skin sheet S suitable for the surface characteristics required for each molded article can be selected and used. In order to prevent blowout and perform good blow molding, it is more preferable to bond the skin sheets S to both sides of the parison P. Is desirably attached to the skin sheet S on the side where the blow ratio increases.

Next, the operation of the lamination blow molding method of the present invention, which is performed using the lamination blow molding machine 1 configured as described above, will be described. First, the skin sheet S is rewound from the roll 20 and hung down while the molds 8 and 8 are opened and held in the mold open state, and the lower end is gripped by the sheet clip 24 and held in the extended state. Next, the tip of the hollow parison P discharged from the die head 2 is sandwiched by a parison pinch and fused to form a bag, and compressed air is injected into the bag-shaped parison P to slightly inflate the parison P. When the lower end of the parison P reaches the lower end of the mold 8, the pair of left and right molds 8 and 8 are closed, and the parison P and the skin sheet S are sandwiched in the cavity space of the mold 8. By blowing compressed air into the parison P through an injection needle (not shown), the parison P and the skin sheet S are pressed against the cavity surfaces of both the dies 8, 8 to form a predetermined shape along the cavity surface. The parison P and the skin sheet S are integrated by being shaped and then cooled and solidified from the mold surface side.

On the other hand, the air cylinder 30a is driven to advance the cutter 30 toward the skin sheet S, and the cutter 30 is moved into the horizontal groove of the cutter seat 30b disposed on the back side of the skin sheet S at a position facing the cutter 30. The cutting edge of the cutter 30 is fitted, the skin sheet S is cut in the horizontal direction in preparation for the next shot, and the molded product is cooled and solidified when a predetermined time has elapsed since the completion of the mold closing and the molded product has cooled. After discharging the compressed air from the inside, the two dies 8, 8 are opened to take out the bonded molded product, thereby completing a series of molding cycles.

(Example 1) Glass fiber-filled PP pellets having a glass fiber length of 9 mm and a glass content of 40%, and unreinforced PP
Pellets are blended in a ratio of 1: 3, and glass fiber reinforced plastic having a glass content of 10% as a whole is used as a resin material of parison P. The size is 600 m.
A table top plate of mx 900 mm x 30 mm was blow molded. A table top molded product molded by a normal blow molding method, a table top molded product in which a 3 mm-thick polyester fabric is adhered to the surface side of the table top as a skin sheet S, and the table top sheet S is The table top plate molded products bonded to both the front side and the back side of the plate were all good.

(Example 2) The ratio of the pellet blend in Example 1 was 1: 1 and the glass content was 20 as a whole.
% Glass fiber reinforced plastic as a resin material of parison P, size 600 mm × 900 mm × 3
A 0 mm table top was blow molded. A table formed by bonding a 3 mm-thick polyester fabric as a skin sheet S to the surface side of a table top plate while a corner portion of the table top plate molded product formed by a normal blow molding method was torn. The top plate molded product and the table top plate molded product obtained by bonding the skin sheet S to both the front side and the back side of the table top plate were all good.
In addition, slight warpage was observed in the table top molded product in which a 3 mm-thick polyester fabric was adhered to the surface side of the table top as a skin sheet. By setting a temperature difference between the set temperatures of the dies 8, 8, it was possible to prevent the warpage of the molded product.

Example 3 The ratio of the pellet blend in Example 1 was 3: 1, and the glass content was 30 as a whole.
% Glass fiber reinforced plastic as a resin material of parison P, size 600 mm × 900 mm × 3
A 0 mm table top was blow molded. While a large tear occurred at a corner of a molded table top formed by a normal blow molding method, a 3 mm-thick polyester fabric was adhered to the surface of the table top as a skin sheet S. The table top molded product was slightly broken at the corners, and the table top molded product obtained by bonding the skin sheet S to both the front side and the back side of the table top did not break. 30% glass content
, The surface condition of the parison P discharged from the die head 2 is considerably deteriorated, and the table top plate molded product formed by the ordinary blow molding method has a poor surface appearance. The surface appearance of the top plate molded product was able to be maintained in a good product range.

The suitable range of the fiber content of the resin material used in the present invention is preferably 15% to 35%, and more preferably 20% to 30%. When the fiber content is less than 15%, the rigidity of the laminated blow-molded product is not sufficiently improved, and when the fiber content is more than 35%, the moldability and the surface appearance of the laminated blow-molded product deteriorate. Considering the balance between the rigidity improvement effect, moldability and surface appearance quality,
The optimal fiber content is between 20% and 30%. In the lamination blow molding method according to the present invention, since the skin sheet S functions as a heat insulating material, the mold set temperature (4) lower than the mold set temperature (about 80 ° C.) in normal blow molding.
(About 0 ° C.) is desirable.

[0016]

As described above, the method of laminating blow molding a fiber reinforced plastic according to the present invention exhibits the following excellent effects. (1) Since the parison is sandwiched between the pair of left and right molds via the skin sheet, the skin sheet functions as a heat insulating material to reduce the cooling speed of the parison, and the parison reinforced by the skin sheet is locally stretched. As a result, the blow-out is prevented from occurring and the good blow molding is performed. (2) Since a fiber-reinforced plastic having a high fiber content, which cannot be molded by the conventional blow molding method, can be used, a blow-molded article having high rigidity can be obtained. (3) Since a skin sheet most suitable for the surface characteristics required for a molded product can be selected and used, a blow-molded product with high added value with improved surface characteristics such as decorativeness, touch feeling, cushioning property, etc. can be obtained. .

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part of a lamination blow molding machine according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lamination blow molding machine 2 Die head 8 Die 8a Medium passage 8b Vent hole 10 Collecting duct 11 Exhaust pipe 12 Solenoid valve 14 Suction fan 20 Roll 22 Roll stand 24 Sheet clip 30 Cutter 30a Air cylinder 30b Cutter seat P Parison S Skin sheet

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F208 AA11 AB25 AD05 AD08 AG03 AG07 AR12 LA01 LA05 LB01 LB13 LB19 LG01 LG03 LG22 LJ05 LJ09

Claims (2)

[Claims] 1. A lamination blow molding method using a fiber reinforced plastic as a resin material of a parison, wherein a hollow parison extruded from a die is hung between a pair of left and right molds opened. After interposing a skin sheet between the parison and one or both of the pair of left and right molds, the molds are closed, and a pressurized fluid is blown into the parison to pressurize the parison. By inflating and pressing the parison and the skin sheet against the cavity surface of the mold, the skin sheet and the parison are integrally bonded and shaped into a predetermined shape. Blow molding method of fiber reinforced plastic. 2. A parison resin material having a fiber length of 3 to 1
2. The method of laminating and blowing a fiber reinforced plastic according to claim 1, wherein a 0 mm long fiber reinforced plastic is used.