JPH10264168A - Urethane molding die and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture an inexpensive mold, extend the useful life of the mold and improve productivity. SOLUTION: Resin layers 18 are formed on one mating surface 10b, 16a and 17a of matching surfaces of molds 10, 11, 16 and 17 forming a closed cavity by mating a plurality of molds on their mating surfaces. The surfaces of the resin layers 18 are formed into mating surfaces made to fit to the other mating surfaces 10a, 11a and 11b in forming the resin layers 18. Even when the processing accuracy of the molds is low, the generation of flashes is prevented and inexpensive molds can be manufactured by the arrangement, and also the surfaces of resin layers are brought into contact with the surfaces on which the resin layers are formed, and the facial pressure per unit area of the resin layers 18 is lowered to extend the useful life, and the repair of the molds is carried out easily to improve the working efficiency of a urethane molding line and also improve productivity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art First, an outline of a urethane foam molding line will be described with reference to FIG. In the figure, the urethane foam is opened in a mold opening step 1 and then the product is taken out of the mold in a mold removal step 2. Then, after the mold is cleaned in the cleaning step 3, the mold release agent is applied in the cavity in the mold release agent application step 4, and then the accessory attachment step 5 for setting accessories such as hardware necessary for the product, After the accessory was set in the mold, the mold was closed in a mold closing step 6 for closing the mold, and then urethane was injected in a urethane injection step 7, and then urethane was injected in an injection port closing step 8. Close mouth and seal cavity completely. While moving in the foaming / curing line 9 in this state, the urethane injected into the cavity foams and cures to become a product. Steps 1 to 9 are performed at a constant speed while continuously moving.

[0003] As shown in FIG.
The removal of the burrs 15a, 15b and 15c is carried out by operations such as pinching and a cutter knife. Therefore, the productivity is low and the disposal of the removed burrs involves problems such as pollution. Therefore, it is desirable to prevent burrs from appearing on the product surface of the urethane foam molded article. As a conventional example of the urethane foam mold, dies 10, 11, 16, and
The 17 mating surfaces 10a, 10b, 11a, 11b, 16a, 17a are precisely machined and the mating surfaces are subjected to electrical discharge machining,
The mating surfaces are precision finished.

[0004] In place of this precision machining or electrical discharge machining, as means for sealing the mating surface of the mold,
There is one disclosed in Japanese Patent Application Laid-Open No. Hei 7-300407. In the mold disclosed herein, the urethane rubber layer is formed on one of the mating surfaces (parting lines) of the upper mold and the lower mold, and the other mating surface is used as a cutting edge surface. Utilizing force, the blade tip surface is cut into the rubber layer. By cutting the edge of the blade into the urethane rubber layer, the cavity is completely sealed, preventing urethane from leaking from the mating surface of the upper mold and the lower mold during urethane foam molding. The burr does not appear on the surface. Further, from the viewpoint of reliably preventing the generation of burrs, the urethane rubber layer is provided so as to coincide with the surface of the cavity, so that the urethane rubber layer forms a part of the cavity.

[0005]

In a conventional urethane foam molding die in which burrs do not appear on the surface of the product, precise machining or electric discharge machining is performed on the mating surface of the upper die and the lower die. If urethane is prevented from leaking from the mating surface, there are the following problems to be improved. That is, considerable precision processing is required to process the mating surface of the upper mold and the lower mold so that urethane does not leak during foam molding, which is an expensive mold and is disadvantageous. In addition, on the surface that has been precision-processed in this way, a small amount of deformation or distortion of the mold creates a gap in the mating surface, so the mold must be strong so that there is no slight deformation or distortion. Must. Therefore, the mold itself becomes expensive in addition to the precision processing, and
There is a problem that a large-scale device is required to open and close the mold, and the device itself becomes large and expensive.

Further, when the mating surface of the mold is distorted, the mating surface does not adhere, so that the mating surface needs to be repaired. In order to repair this mating surface,
Since the mold must be removed from the urethane foam molding line shown in Fig. 10 and transported to a machining factory, the urethane foam molding line is suspended during that time, and there is a problem in terms of productivity. In the case of processing, since the processing requires a long time, there is a problem in terms of productivity. Further, since the electric discharge machining equipment is expensive, there is a problem in that the equipment cost is eventually reduced to a urethane foam molded article, resulting in an expensive product, and the product value is reduced.

Further, as in a mold disclosed in Japanese Patent Application Laid-Open No. 7-304407, a urethane rubber layer is formed on one of the mating surfaces of an upper mold and a lower mold, and the other mating surface is used as a cutting edge. In the case where the blade tip surface is brought into close contact with the urethane rubber layer by making it bite, the above-described precision processing is not necessary, and the die can be reduced in weight, but the blade tip surface is pressed. Since concentrated stress is applied to the urethane rubber layer, the part of the urethane rubber layer where the concentrated stress is generated becomes fatigued and fragile during use of the mold for a long period of time, resulting in a reduction in the service life. There is a problem.

[0008] Step 4 of applying a release agent to the mold (see FIG.
In order to improve the productivity by omitting step 10), a mold in which the inner surface of the cavity is subjected to Teflon processing is used. Therefore, when the urethane rubber layer is exposed on the cavity surface and the urethane rubber layer is made a part of the cavity as in the mold disclosed in Japanese Patent Application Laid-Open No. 7-304047, the following problem occurs. That is, since the mold release agent is not applied to the mold that has been subjected to Teflon processing, the urethane rubber layer that has not been subjected to Teflon processing and has not been applied with the release agent is exposed on the cavity surface. As a result, a part of the foamed product in the cavity adheres to the urethane rubber layer. Then, mold opening step 1 (see FIG.
When the molds 10 and 11 are opened as shown in FIG. 7 in 10), a part 13 of the product 15 adheres to the urethane rubber layer 12 and is torn off, and a recess 14 is formed in the product 15 to generate a defective product. There is a problem.

According to the present invention, an inexpensive mold is provided, the service life of the mold is extended, the productivity is improved, and a defective product is prevented from occurring even in a Teflon-treated mold. An object of the present invention is to provide a urethane molding die and a method for manufacturing the same.

[0010]

Means for solving the above problems are as follows from the description of claim 1 according to the present invention.
In a urethane molding mold in which a plurality of molds are joined together at a mating surface to form a closed cavity, a resin layer is formed on one of the mating surfaces of the mold, and the surface of the resin layer is a resin layer. A mating surface adapted to the other mating surface that is not formed is characterized.

Next, the means grasped from the second aspect is characterized in that the resin surface is not formed by a predetermined dimension from the cavity surface.

[0012] Next, a means understood from the third aspect is a mold for forming a resin surface in a urethane molding mold in which a plurality of molds are joined on a mating surface to form a closed cavity. After cleaning the mating surface, apply a predetermined amount of resin, apply a release agent so that the resin does not adhere to the mating surface of the mold on which the resin layer is not formed, and then close the mold to remove the resin. The resin is solidified by combining the applied mating surface with the mating surface applied with the release agent.

Next, how the problem is solved by the present invention as understood from the description of each claim will be described. First, in the present invention grasped from the description of claim 1, a plurality of molds are joined by a mating surface, and a surface of a resin layer formed on one of mating surfaces of a mold forming a closed cavity is formed by a resin layer. Even if the processing accuracy of the surface on which the resin layer is applied and the surface on which the resin layer is not applied is low, the surface of the resin layer and the resin layer are formed Even if the non-contacted surface is brought into surface contact, the gap between the mating surfaces of both surfaces can be eliminated.

Next, in the present invention as understood from the second aspect, by preventing the resin surface having a predetermined size from being formed from the cavity surface, burrs are positively generated in portions where the resin layer is not applied. Let it.

[0015] Next, in the present invention as understood from the third aspect, a predetermined amount of resin is applied after cleaning a mating surface of a mold that forms a resin surface with low processing accuracy, thereby improving processing accuracy. Cover the lower mating surface with a resin layer, apply a release agent so that the resin does not adhere to the mating surface of the mold on the side where the resin layer is not formed, then close the mold and apply the resin to the mating surface By mating with the mating surface to which the release agent has been applied, the resin layer can be applied to the surface where the resin layer is not formed before the resin layer is not cured, and the release agent is applied to the surface where the resin layer is not formed in the previous process. Since the resin is applied, the mold is opened after solidifying the resin to form a surface of the resin layer that does not form the resin on one mating surface of the mold and that has been applied to the mating surface of the other mold. I do.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention as understood from the description of the above claims will be described. First, the embodiment of the present invention grasped from the description of claim 1 is shown in FIG.
As shown in FIG. 5, a plurality of molds 10, 11, 16, and 17 are joined together at a mating surface to form a closed cavity 19 (FIG. 5). A resin layer 18 is formed on the mating surfaces 10b, 16a, 17a.
18 to the other mating surface 10 on which the resin layer 18 is not formed.
Make the mating surfaces familiar with a, 11a, and 11b.

Next, according to the embodiment of the present invention which is understood from the description of the second aspect, as shown in FIG. 1, the resin layer 18 is not formed from the surface of the cavity 19 by a predetermined dimension H1, H2, H3. To

Next, according to the embodiment of the present invention which is understood from the description of claim 3, in FIG. 3, the mating surfaces 10b, 16a, 17a of the dies 10, 16, 17 forming the resin layer 18 are cleaned. After that, a predetermined amount of resin is applied, and a release agent is applied so that the resin does not adhere to the mating surfaces 10a, 11a, 11b of the molds 10, 11 on which the resin layer 18 is not formed. The mold is closed, and the mating surface on which the resin is applied and the mating surface on which the release agent is applied are joined to cure the resin.

Hereinafter, embodiments of the present invention will be described in more detail. In the following description, as shown in FIG. 8, as an example, a mold for molding a headrest including a stay 20 as a product 15 will be described. FIG. 9 shows a mold for molding the headrest, and the respective molds 10, 11, 16, 17 are shown.
Are openably and closably connected by hinges 21, respectively.

First, the method of manufacturing the mold will be described. Referring to FIG. 3, the molds 10, 16, 17 for forming the resin layer 18 are shown.
After cleaning the mating surfaces 10b, 16a and 17a, a predetermined amount of resin (for example, a thickness of about 0.1 to 0.3 mm) is applied. Thus, even if the processing accuracy of the mating surfaces 10a, 16a, and 17a is low, the surfaces are covered with the resin. Also, the resin layer 18
Mating surfaces 10a, 11a,
Apply a release agent so that resin does not adhere to 11b.

By applying the release agent, the mating surface on which the release agent is applied is pressed against the resin layer 18 in a state where the resin layer 18 is not yet cured, so that the mating surface on which the release agent is applied is formed. Improves the movement of the resin of the resin layer 18 without adhering to the mating surface to which the release agent has been applied (it adapts to the movement of this resin) according to the processing accuracy (undulation and unevenness), and forms a more accurate surface Is done. With the release agent applied in this way to improve familiarity, the mold is closed and the mating surface coated with the resin is mated with the mating surface coated with the release agent as shown in FIG. The resin layer 18 is applied to the mating surfaces 10a, 11a, and 11b, and the resin layer 18 is hardened to form a surface of the resin layer 18 that has been applied to the mating surfaces 10a, 11a, and 11b.

As shown in FIG. 1, in order to prevent the height H1, H2, and H3 resin layers 18 from being formed from the surface of the cavity 19, the resin is applied by masking this portion. . The inner surface of the cavity 19 is subjected to Teflon processing. Further, the portions of the heights H1, H2, and H3 where the resin layer 18 is not formed may be subjected to Teflon processing, and the mating surface where the resin layer 18 is not formed may be subjected to Teflon processing. This height H1, H
2. H3 is based on the allowable height of burrs that do not require the removal of burrs as a product, and the height is several millimeters.

In FIG. 3, the formation surface of the resin layer 18 is set to the mating surfaces 10b, 16a and 17a because the resin layer 18 can be formed with the working posture upward, and the resin layer 18 on the resin molding line can be formed. This is to make repair work of 18 easier. Also,
Instead of the mating surface 10b of the mold 10, the mating surface 11a of the mold 11
Alternatively, the resin layer 18 may be formed on the substrate. As the resin, a polyester resin is used, and a two-pack type resin is used.

Next, the operation will be described. The mold shown in FIG. 1 has a height H1, H2, H3 resin layer 1 from the surface of the cavity 19.
8 is not formed, and the inner surface of the cavity 19 is subjected to Teflon processing. In the state of completion of molding (a) in FIG. 4, the heights H1, H
2. Since the resin layer 18 is not formed on the portion of H3 (FIG. 1), burrs 15a, 15b and 15c having a thickness substantially equal to that of the resin layer 18 are positively applied to the portion as shown in FIG. And the ends of the burrs 15a, 15b, 15c adhere to the resin layer 18.

Next, when the mold is opened in the step shown in FIG. 4B, as shown in FIG.
b, the product 15 is prevented from breaking. Since the length of the burr 15b is limited by the resin layer 18,
It is not necessary to remove the burrs 15b 'remaining on the product 15 by breaking. As shown in FIG. 3, a burr 15b 'is formed on the resin layer 18 side.
If any adheres, remove it.
The amount of 15b 'is extremely small, which can reduce the inconvenience caused by the disposal of burrs. Similarly, when removing the product 15 by removing the mold in FIG.
Since the lengths of a and 15c are limited, the removal of burrs can be omitted, and the product 15 can be prevented from breaking because it breaks at the weakest burrs 15a and 15c.

Next, in the step (d), the mold is cleaned and a release agent is applied. However, since the inner surface of the cavity 19 is subjected to Teflon processing, application of the release agent becomes unnecessary. In addition, since part of the product does not adhere to the cavity 19, there is no need for cleaning, and this step can be omitted. Next, in the step (e), the stay 20 as an accessory of the product 15 is set, and in the step (f), the mold is closed. In closing the mold, the surface of the resin layer 18 is adapted to the mating surface of the mating side, so that the cavity 19 can be hermetically sealed, and the resin layer 18 and the mating mating with the resin layer 18 can be performed. Since the surface is in surface contact and there is no local pressing, the surface pressure per unit area of the resin layer 18 can be reduced. Then, in step (g), urethane 15 'is injected.

Next, as shown in FIG. 5, in a mold in which the resin layer 18 is exposed on the surface of the cavity 19 and the resin layer 18 is a part of the surface of the cavity 19, the surface of the resin layer 18 is Since the surface is adapted to the mating surface, when the mold is closed, the surface of the resin layer 18 and the mating surface of the mating side are in close contact with each other, and the generation of burrs is prevented. In addition, since urethane adheres to the resin layer 18, the release agent is also applied to the resin layer 18 exposed on the surface of the cavity 19 in the release agent application step of FIG. As a result, there is no adhesion of the product at the time of opening and removing the mold, and tearing of the product 15 can be prevented.

The dies 10, 11, 16 and 17 are connected by a hinge 21. If the mating surfaces do not fit due to wear of the hinge 21 or distortion of the dies, the resin layer 18
The resin is further applied on the top, the mold is closed before the resin is cured, and the newly applied resin is mixed in, so that the excess resin moves and the surface of the resin layer 18 is brought into contact with the mating surface of the mating side. The surface of the resin layer 18 can be formed by curing the resin as it is. Thus, the mating surface of the resin layer 18 can be repaired without removing the mold from the urethane molding line.

In FIG. 5, when considering that there is no resin layer 18, the two mating surfaces 10a and 10
b, 11a, and 11b. These two surfaces are each 16
Although it is extremely difficult to machine so that a and 10a, 10b and 11a, and 11b and 17a are all in close contact, a resin layer 18 is formed on the mating surfaces 16a, 10b, and 17a as shown in FIG. By closing the mold, all the mating surfaces including the hinge 21 installation error are aligned at the same time,
The surface of the resin layer 18 is adapted to the mating surface of the other side, and the mating surfaces 16a and 10a, 10b and 11a, and 11b and 17a
Can be easily formed even at the time of repair so that all of them are in close contact with each other.

[0030]

According to the present invention, which is understood from the detailed description of the present invention based on the claim 1 as described in detail above, a plurality of molds are joined by a mating surface to form a closed cavity. The surface of the resin layer formed on one of the mating surfaces of the mold to be formed is a mating surface that is adapted to the other mating surface on which the resin layer is not formed, and the surface on which the resin layer is formed and the surface on which the resin layer is not formed are processed. Even if the precision is low, or even if the surface of the resin layer and the surface on which the resin layer is not formed are in surface contact, the gap between the mating surfaces of both surfaces can be eliminated, so use an inexpensive mold. To improve productivity by preventing the generation of burrs and eliminating the work of removing burrs, further reducing the surface pressure per unit of the resin layer, prolonging the service life, and facilitating mold repair. To improve the operation rate of the urethane molding line, It can be improved.

Next, according to the present invention, which is understood from the detailed description of the present invention, based on the description of the second aspect, the resin layer is applied so that the resin surface of a predetermined size is not formed from the cavity surface. Since the burr was positively generated on the non-existing parts, the product was prevented from tearing when opening and removing the mold, eliminating the occurrence of defective products and using a Teflon-treated mold. The productivity can be improved by omitting the step of applying the release agent.

Next, according to the present invention, which is understood from the detailed description of the invention based on the third aspect, after cleaning the mating surface of the mold forming the resin surface with low processing accuracy, the predetermined amount is obtained. Resin, coat the mating surface with low processing accuracy with a resin layer, apply a release agent so that the resin does not adhere to the mating surface of the mold on the side where the resin layer is not formed, and then close the mold. The mating surface coated with the resin and the mating surface coated with the release agent are combined, and the resin layer is applied to the surface where the resin layer is not formed before the resin layer does not cure, and the resin layer is formed in the previous process Since the mold release agent was applied to the surface not to be molded, the mold was opened after the resin was solidified, so that it was adapted to the mating surface of the other mold where no resin was formed on one mating surface of the mold. Since the surface of the resin layer is formed, the processing accuracy of the mold is lowered to make the mold inexpensive. Rukoto can, thereby improving the productivity and preventing the occurrence of burrs is omitted deburring process,
The service life of the resin layer can be extended and the repair work of the mold can be facilitated, the operation rate of the urethane molding line can be improved, and the productivity can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a main part of an embodiment of the present invention in a partially enlarged manner.

FIG. 2 is an enlarged longitudinal sectional view showing a main part of the mold shown in FIG. 1 after molding is completed.

FIG. 3 is a longitudinal sectional view showing a state in which the mold in FIG. 1 is opened.

FIG. 4 is a view showing a process of urethane molding.

FIG. 5 is an enlarged longitudinal sectional view showing a main part of another embodiment of the present invention.

FIG. 6 is an enlarged longitudinal sectional view showing a main part when urethane molding is performed using a conventional mold.

FIG. 7 is a longitudinal sectional view showing a state where a conventional mold is opened.

FIG. 8 is a perspective view of a headrest shown as an example of a urethane molded product.

9 is a longitudinal sectional view showing a mold for molding the headrest in FIG.

FIG. 10 is a schematic diagram showing a urethane molding line.

[Description of sign]

 10 Mold 11 Mold 15 Product 16 Mold 17 Mold 18 Resin layer 19 Cavity 20 Stay 21 Hinge

Claims (3)

[Claims] 1. A urethane molding die in which a plurality of molds are joined together at a mating surface to form a closed cavity, a resin layer is formed on one of the mating surfaces of the molds, and A mold for urethane molding, characterized in that the surface is a mating surface adapted to the other mating surface on which no resin layer is formed. 2. The urethane mold according to claim 1, wherein the resin surface is not formed from the cavity surface by a predetermined dimension. 3. A urethane molding die in which a plurality of molds are joined together at a mating surface to form a closed cavity, and a predetermined amount of resin is applied after cleaning the mating surface of the mold forming the resin surface. Then, apply a release agent so that the resin does not adhere to the mating surface of the mold on which the resin layer is not formed, and then close the mold and the mating surface with the resin applied and the mating surface with the mold release agent applied. A method for manufacturing a urethane molding die, comprising: