JPH10272656A - Molding method of hollow article and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the strength of article resin stronger than the strength of joining resin by mounting separately a molding cylinder for conducting molding of semi-molded article and a joining cylinder for joining both semi-molded articles and forming a hollow article. SOLUTION: A stationary mold 23, an intermediate mold 28 and a transfer mold 26 are disposed to subsequently cause a molding cylinder 31 to be joined to a hot runner 30 of the intermediate mold 28. By the use of a molding cylinder 31, molten resin is injected in the cavity via the hot runner 30 for forming a hollow semi-molded article. Then, mold clamping force to the transfer mold 26 is released while holding the molded article to each female mold of the stationary mold and transfer mold, and the transfer mold 26 is dislocated leftward so as to disengage the intermediate mold 28 from the interstice between both molds 23, 26 and bring the transfer mold 26 into close contact with the stationary mold 23. A joining cylinder 24 is connected to a runner 23 of the stationary mold 23 before supplying joining resin around the opening periphery of semi-molded articles being faced with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding a hollow product made of synthetic resin and an apparatus therefor. The present invention relates to a molding method and an apparatus therefor.

[0002]

2. Description of the Related Art As a method of manufacturing a hollow molded article made of synthetic resin, a two-part joining method such as blow molding, hot plate welding, vibration welding, ultrasonic welding, and bonding with an adhesive is known. Japanese Patent Application Laid-Open No. Sho 62-87315 discloses a method of obtaining the composition only by molding.
No. 1993. This example is shown in FIGS. 15 and 16. In the conventional hollow molding method, a movable mold having a sprue 2, a male mold 3 and a female mold 4, and a male mold 6 and a female mold 7 are provided. This is a structure including a mold 8 and an injection cylinder 9 connected to the sprue 2. In the production of a semi-molded product, first, as shown in FIG. 15, the two molds 5 and 8 are opposed to each other, and the molten resin is injected into the molding space via the sprue 2 and the runner 10 using the injection cylinder 9. To manufacture. Next, after the movable mold 8 is opened to the left and the slide mold 5 is further slid upward, one female mold 4 is connected to the other female mold 7.
And the opening edges of the semi-molded article are opposed to each other to obtain a state shown in FIG. Using the same injection cylinder 9, the joining resin is injected around the edge of the facing semi-finished product through the other sprue 2 to obtain a hollow final product 11. Next, the two molds 5 and 8 are separated, and the hollow final product 11 is taken out from both the molds 5 and 8.

[0003]

In the conventional molding method described above, since the molding cylinder and the joining cylinder are the same, the optimum conditions (molding resin temperature) suitable for joining semi-molded products are set. , Material, cylinder size, etc.) cannot be injected. That is, the product resin and the joining resin are of the same material, and even if the joining resin of the same material is injected around the opening of the cured semi-molded product, sufficient strength cannot be obtained in welding them. .

Therefore, an object of the present invention is to solve the above-mentioned disadvantages of the prior art.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention basically comprises a molding cylinder for molding a semi-molded product, and a hollow product formed by joining the two semi-molded products. Technical means for separately mounting the joining cylinder to be made is adopted. By adopting this means, the product resin and the joining resin of the semi-molded product can be changed. In this case,
The strength of the joining resin can be higher than the strength of the product resin. In addition, when a semi-molded article is molded and when semi-molded articles are joined together, the molding temperature can be changed, so that the joining strength can be improved. In addition, the injection amount of resin at the time of molding can be changed by using different cylinders in the case of molding a semi-molded product and in the case of joining. Can be improved. By changing the resin of the semi-molded product and the joining resin, it is possible to use a resin with a higher joining resin strength than that of the product resin. By increasing the height, the resin in the vicinity of the bonding surface of the semi-molded product is melted together at the time of bonding, so that the bonding strength can be improved.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION A hollow product forming apparatus 21 has a fixed mold 23 supported on a fixed platen 22. Fixed mold 23
Has a joining runner 25 which has a cavity 20 for the blank and which cooperates with a joining cylinder 24. A moving mold 26 facing the stationary mold 23 and having a cavity for a semi-molded article concentric with the cavity of the stationary mold 23;
Are arranged so as to be able to approach and separate from the fixed mold 23. The movable mold 26 has a structure that receives a mold clamping force from a direct pressure type mold clamping device 27. A middle mold 28 is arranged between the two molds 23 and 26. The core 2 which enters the opposing cavity on both sides of the middle mold 28
A hot runner 30 provided therein and having therein 9 and 29
Can be connected to the molding cylinder 31. The fixed mold 23, the middle mold 28, and the movable mold 26 are arranged in the relationship shown in FIG. 1, and the molding cylinder 31 is connected to the hot runner 30 of the middle mold 28. Using a molding cylinder 31, the molten resin is injected into the cavity through the hot runner 30 to produce a hollow semi-molded product.

As the resin for the product, glass fiber 30 is used.
A polyamide 6 resin containing about 35% is used. Apart from this, for example, those obtained by adding glass fibers to polypropylene, ABS, polycarbonate, polyphenylene sulphite, polybutylene terephthalate, polyethylene terephthalate or polyacetal can also be used.

After injection molding the semi-molded product, as shown in FIG. 2, the mold clamping force to the movable mold 26 is released while holding the molded product in the female mold of the fixed mold and the movable mold, and the mold is moved. The mold 26 is shifted to the left, the middle mold 28 is removed from between the two molds 23 and 26, and then the movable mold 26 is brought into close contact with the fixed mold 23 as shown in FIG. Joining cylinder 24 to fixed mold 23
Of the semi-molded article facing each other to supply the joining resin.

As a joining resin, glass fiber (for example,
Polyamide 6 or polyamide 6.6 resin containing 35 to 50%, preferably 50% is used (φ 13 microns, length 200 to 300 microns). Apart from this, for example, those obtained by adding glass fibers to polypropylene, ABS, polycarbonate, polyphenylene sulphite, polybutylene terephthalate, polyethylene terephthalate or polyacetal can also be used.

Polyamide 6 containing 50% of glass fibers is
Its tensile strength can be increased by 30% as compared with polyamide 6 containing 35% of glass fibers. For this reason, the tensile strength of the joining resin portion of the hollow product can be increased. In this case, if the polyamide 6 resin containing no glass fiber is used as the resin for the product, the adhesiveness between the resin of the semi-molded product and the resin for joining is improved, and the sealing property is improved.

After the joining operation of the facing semi-molded products is completed, FIG.
As shown in FIG. 5, the movable mold 26 is largely shifted to the left, the fixed mold 23 is further moved to the left from the fixed platen 22, the hollow molded article 33 supported by the movable mold 26 is removed, and
The solid product 32 in the runner 25 is withdrawn from the fixed mold 23, and is removed to form the state shown in FIG. Next, the fixed mold 23 is supported by the fixed platen 22, and the middle mold 28 is
It is arranged again between 3 and 26. The middle mold 28 is brought into close contact with the fixed mold 23, and further moved to the middle mold 28 to fix them. Then, the state shown in FIG. 1 is obtained. Again, the molding operation of the hollow molded article 33 described above is repeated. The stroke of the movable mold 26 from the state of FIG. 2 to the state of FIG. 3 and the movable mold 2 for obtaining the state of FIG. 1 from the state of FIG.
Since the stroke is different from the stroke of No. 6, the stroke of the movable mold 26 and the moving speed thereof are controlled using a computer.

A second embodiment of the present invention will be described. In FIG. 6, a hollow product forming apparatus 21 'includes a fixed mold 22', a middle mold 23 ', and a movable mold 24'. The fixed mold 22 'has a concave surface 25' on one surface and a molding surface on the other surface. Resin cylinder 2
6 'and a joining resin cylinder 27'. The molding cylinder 26 'is connected to a hot runner 28' leading to the center of the concave surface 25 ', and the joining cylinder 27' is connected to a joining runner 29 'leading to the side of the concave surface 25'. You. A holding surface 30 'is formed outside the side wall on which the concave surface 25' of the fixed mold 22 'is formed. One surface of the middle mold 23 'is convex surface 3
1 'and the other surface is a concave surface 32'. Medium 23 '
Has a runner 33 'at the center thereof which communicates with the hot runner 28'.
4 'is provided. The middle mold 23 'can be inverted (180 degrees in angle) around the center 35', and the concave face 25 'of the fixed mold 22' is provided with the convex face 31 'or the concave face 3
2 'can be selectively opposed. The movable mold 21 'is movable so as to approach or separate from the fixed mold 22', and has a convex surface 36 'on one surface thereof and a pressing block 37' on the side.
Has. For the fixed mold 22 ', the middle mold 23' and the movable mold 2 '
4 'is matched and clamped. A cavity for the semi-molded product is provided between the fixed mold 22 'and the middle mold 23', and a cavity 2 for the remaining semi-molded product is provided between the middle mold 23 'and the movable mold 24'.
Then, a molten resin is injected into these cavities 20 'and 20' via a hot runner 28 'and a runner 33' using a molding cylinder 26 '.

As the resin for the product, glass fiber 30 is used.
A polyamide 6 resin containing about 35% is used. Apart from this, for example, those obtained by adding glass fibers to polypropylene, ABS, polycarbonate, polyphenylene sulphite, polybutylene terephthalate, polyethylene terephthalate or polyacetal can also be used.

Thus, a pair of semi-molded products 38 'and 39' each having a half-finished hollow product in each cavity 20 'is obtained (see FIG. 7). Next, the middle mold 23 'and the movable mold 24'
Are separated from each other (see FIG. 8). The middle mold 23 'is turned around the rotation center 35' as an axis, the semi-molded product 39 'faces the semi-molded product 38' of the fixed mold 22 ', and the holding block 34' of the middle mold 23 'is moved to the movable mold 24'. (See FIG. 9). After inverting the middle mold 23 ', the fixed mold 22', the middle mold 23 'and the movable mold 24' are joined together and clamped as shown in FIG. A runner 29 'is provided on the side of the opening edge of the facing semi-molded product 38', 39 '.
, A joining resin is supplied from the joining cylinder 27 '. Thus, a hollow product is formed. After the molding of the hollow product is completed, the middle mold 23 'and the movable mold 24' are moved to take out the hollow product.

Glass fibers 35 to 50 are used as the joining resin.
%, Preferably 50% polyamide 6 or polyamide 6.6 resin. Apart from this, for example, those obtained by adding glass fibers to polypropylene, ABS, polycarbonate, polyphenylene sulphite, polybutylene terephthalate, polyethylene terephthalate or polyacetal can also be used.

The mold clamping is of a direct pressure type, but since a semi-molded article is made with the cavities facing each other, the mold clamping force of the mold may be smaller than in the past. In addition, since the molded products can be opposed to each other without sliding the mold, even if the molded products are long, small equipment can be used.

FIG. 11 shows a molding apparatus 40 '. On the base 41 ', a stationary mold frame 42' holding the molding cylinder 26 ', the joining cylinder 27' and the stationary mold 22 'is fixed. The direct pressure type clamping cylinder 43 ′ is fixed to the base 41 ′ so as to be opposed to the stationary mold frame 42 ′. The direct pressure type clamping cylinder 43 'and the fixed frame 42' are connected by a plurality of tie bars 44 ', and the middle frame 45' and the movable frame 46 'movable along these tie bars 44' are connected. Distribute. The movement of both frames 45 'and 46' is based on the tie bar 44 'and the base 4
Guided by rail 47 'on 1'. The middle mold 23 'is supported on the middle frame 45' so as to be rotatable around the center of rotation 35 '. Half rotation of the middle mold 23 'is performed by a cylinder 48', and forward and backward movement of the middle frame 45 'is performed by a cylinder 49'. The movable mold frame 46 'is moved back and forth by a direct pressure mold clamping cylinder 43'. 50 '
Is a cylinder for a positioning stopper of the middle die 23 '. The cylinder 49 'is operated to move the medium frame 45' back and forth with respect to the fixed frame 42 ', and the cylinder 48' is operated to move the medium 23 'to the medium frame 4.
It is inverted around the rotation center 35 'in 5'. Actuation of cylinder 43 'allows for mold clamping. In addition, each mold 22 ',
The movement of 23 'and 24' is as described with reference to FIGS.

A hollow forming apparatus 51 according to a third embodiment shown in FIGS. 13 and 14 has a stationary mold 52 and a movable mold 53 which can be opposed to and separated from each other.
Has a cavity 54 and a core 55 that create a space corresponding to the cross-sectional shape of a half-molded product that forms a half of a hollow product. The movable mold 53 has a runner 56 connecting the cavities 54, 54, and the runner 56 communicates with a gate 57 provided on the fixed mold 52. The exit of the gate 57 is a product cylinder 58
From the molten resin. The fixed mold 52 has another sprue 59 sandwiching the cavity 54, and connects the sprue 59 to the joining cylinder 60. Preferably, the joining cylinder 60 is arranged in parallel with the product cylinder 58. Alternatively, a joining cylinder 60 'may be attached to one of the upper and lower surfaces of the movable mold 52 (see FIG. 13).

In the production of a semi-molded product, first, as shown in FIG.
Using 8, a molten resin is injected into the cavities 54, 54 via the sprue 57 and the runner 56 to produce a semi-molded product. Next, the moving mold 53 is opened rightward, and the moving mold 53 is opened.
And move the mold 5 at a position where the two semi-molded products face each other.
3 is opposed to the fixed mold 52. Using a joining cylinder 60 or 60 ', a sprue 59 and a runner 61 are used to inject molten resin around the joining edge of the semi-molded product, and the two semi-molded products are brought into contact to form a hollow product. Thereafter, the two molds 52 and 53 are separated, and the final hollow product is taken out. As the resin for the product, a polyamide 6 resin containing 30 to 35% of glass fiber is used. Separately, for example, polypropylene, AB
S, polycarbonate, polyphenylene sulfite,
Polybutylene terephthalate, polyethylene terephthalate, or polyacetal obtained by adding glass fibers can also be used. Glass fiber 35 as a joining resin
Polyamide 6 or polyamide 6.6 resin containing 50% to 50%, preferably 50% is used. Apart from this, for example, those obtained by adding glass fibers to polypropylene, ABS, polycarbonate, polyphenylene sulphite, polybutylene terephthalate, polyethylene terephthalate or polyacetal can also be used.

FIG. 12 shows the change in the tensile strength of the polyamide 6 according to the change in the amount of the glass fiber. The tensile strength gradually increases when the content of the glass fiber is 30 to 50%, but the content of the glass fiber with respect to the thermoplastic resin is limited to 50%. If it is more than this, the resin does not adhere around the glass fiber, so that molding cannot be performed, and the impact strength decreases.

As an experimental example, a groove having a depth of 3 mm and a width of 2 mm is formed on the outer periphery of the joining surface of the semi-molded product, and the pair of semi-molded products are joined together, and a joining groove having a depth of 3 mm and a width of 4 mm is opened to the outside. Then, polyamide 6 containing 50% of glass fiber was injected into the joining groove as a joining resin. The semi-molded article was molded using polyamide 6 containing 30% of glass fiber. The bonding strength was 698 kg / cm ² . The bonding strength when polyamide was used as the bonding resin was 427 kg / cm ² , and even when polyamide 6 containing 30% glass fiber was used as the bonding resin, the bonding strength was only about 441 kg / cm ^2. Did not. Since the molding temperature of polyamide 6 is 290 ° C. and the molding temperature of polyamide 6.6 is 305 ° C., the molding temperature at the time of joining is higher than the molding temperature at the time of producing a semi-molded product. The resin in the vicinity of the joint surface of the molded article is also melted together, so that the joint strength is improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a molding state of a semi-molded product according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a state in which a middle mold according to the first embodiment of the present invention is removed.

FIG. 3 is a view showing a joined state of a semi-molded product in the first embodiment of the present invention.

FIG. 4 is a view showing removal of a hollow molded product according to the first embodiment of the present invention.

FIG. 5 is a diagram showing rearrangement of a middle mold according to the first embodiment of the present invention.

FIG. 6 is a view showing a fixed type, a medium type, and a movable type according to a second embodiment of the present invention.

FIG. 7 is a diagram showing molding of a semi-molded product according to a second embodiment of the present invention.

FIG. 8 is a view showing a state in which a middle mold according to a second embodiment of the present invention is separated from another mold.

FIG. 9 is a view showing a state in which a middle mold is turned upside down and a semi-molded product is opposed in a second embodiment of the present invention.

FIG. 10 is a view showing a state in which semi-molded articles are joined in a second embodiment of the present invention.

FIG. 11 is a perspective view showing an entire apparatus for forming a hollow product according to a second embodiment of the present invention.

FIG. 12 is a graph showing a change in tensile strength depending on the amount of glass fiber added to polyamide 6.

FIG. 13 is a sectional view of a main part showing a third embodiment of the present invention.

FIG. 14 is a cross-sectional view showing the joining of semi-molded products according to a third embodiment of the present invention.

FIG. 15 is a view showing a conventional molding means.

FIG. 16 is a diagram showing a joining state of a conventional semi-molded product.

[Explanation of symbols]

 Reference Signs List 22 Fixed plate 23 Fixed mold 24 Joining cylinder 25 Joining runner 26 Moving mold 27 Direct pressure mold clamping device 28 Middle mold 30 Hot runner 31 Molding cylinder 22 'Fixed mold 23' Medium mold 24 'Movable mold 25' 32 'concave surface 26' forming cylinder 27 'joining cylinder 28' hot runner 29 'joining runner 31', 36 'convex surface 35' center of rotation 3 ', 34', 37 'holding block 38', 39 ′ Semi-molded product

Continuation of the front page (51) Int.Cl. ⁶ Identification code FI B29K 509: 08 B29L 22:00 (72) Inventor Tomonori Hirano 2-1-1 Asahicho, Kariya-shi, Aichi Pref. Aisin Seiki Co., Ltd. (72) Inventor Yoshiro Hattori 2-1-1 Asahi-machi, Kariya-shi, Aichi Aisin Seiki Co., Ltd. (72) Shozo Nishida 1-6-1, Funakoshi-minami, Aki-ku, Hiroshima-shi, Hiroshima Japan Nippon Steel Corporation

Claims (7)

[Claims] A fixed mold cooperating with a joining cylinder and having a cavity for a semi-molded product, a moving mold cooperating with a direct pressure type clamping device and having a cavity for a semi-molded product, and a hot runner. A mold that is disposed between a moving mold and a fixed mold and that can be approached to and separated from both molds, and a product resin that has been melted into both cavities is injected through a hot runner to form a semi-molded product. A cylinder and a joining cylinder for moving the middle mold after molding the semi-molded product, clamping the moving mold to the fixed mold, and supplying the joining resin around the opening edge of the opposed semi-molded product. Equipment for forming hollow products. 2. A fixed type having a concave or convex surface, a movable type having a reversible medium type having a convex surface on one surface and a concave surface on the other surface, a convex or concave surface, and a fixed type. A molding cylinder that injects the molten product resin into the cavity for the semi-molded product between the middle mold and between the middle and movable molds, and a joining resin on the mating surface when the semi-molded product is inverted by inverting the middle mold And a joining cylinder for supplying the product. 3. A fixed mold having a cavity and a core separated from each other and having a molding cylinder and a joining cylinder separately from each other, and a fixed mold cavity and a fixed mold cavity that can be opposed to the fixed mold core. With a core that can be opposed
A molding apparatus having a movable mold movable away from a fixed mold and in a direction perpendicular to the separating direction. 4. The product resin is polyamide 6 containing 30 to 35% of glass fiber, and the joining resin is glass fiber 35.
The hollow product forming apparatus according to any one of claims 1, 2, and 3, wherein the apparatus is polyamide 6 or polyamide 6.6 containing up to 50%. 5. The resin for product is polyamide 6 containing no glass fiber, and the resin for bonding is 35 to 50% of glass fiber.
The hollow product molding apparatus according to any one of claims 1 to 3, wherein the molding apparatus is polyamide 6 or polyamide 6.6. 6. The molding temperature at the time of joining is set higher than the molding temperature at the time of producing a semi-molded product.
An apparatus for forming a hollow product according to any one of the above. 7. A movable mold having a cavity for a semi-molded article is brought into contact with a first stationary mold having a cavity for a semi-molded article and a runner communicating with the cavity, for a molded article mounted on the fixed mold. First molten resin for product from cylinder
Injection into the cavity for a semi-molded product through the runner of the above, the opening edges of both the semi-molded products are brought into contact with each other, and the joining cylinder mounted on the fixed mold via the second runner provided on the fixed mold A method for molding a hollow product, comprising: injecting a molten resin for joining into the opening edges of the two semi-molded products from the mold; and taking out the joined two half-molded products.