JPH07232332A - Mold made of resin - Google Patents

Abstract

PURPOSE:To enhance durability as a mold and improve inferior thermal conductivity by specifying the difference in a thermal expansion coefficient between members constituting a molding face layer and a metallic backing part, respectively. CONSTITUTION:A model (wooden mold) 14 having a face exactly like the shape of an article to be molded is covered with a metallic backing 2 having a molding face layer 1 of 20mm in a wall thickness and a space corresponding to a width of 30mm at a circumferential part 6 on a parting face. Then, a composite resin material 15 comprising resin and a filler mainly composed of metallic powder is cast into a space defined by the model 14 and the backing 2, and casting is performed by applying pressure to the composite resin material. After casting, the whole is heated, and a surface layer part is caused to be primarily cured. After the model is opened, secondary cure is performed to form the molding face layer 1, and a mold (top force) 3 is obtained. In this case, the difference in a thermal expansion coefficient between the metallic backing member and the composite resin material is made to be at most 5X10<-6>/ deg.C. By this method, peeling and cracking of the molding face layer are not caused.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin molding die in which a molding surface layer made of resin is backed and supported by a metal backing portion.

[0002]

2. Description of the Related Art Among molding dies for plastics,
Conventionally, resin molds that can be manufactured at a lower cost and with shorter delivery times than molds have been used as simple molds for trial manufacture and molds for small-lot production.

These resin molds have problems such as low strength and durability as a mold and a decrease in molding efficiency due to the low thermal conductivity of the resin material itself. A resin having high strength and thermal conductivity has been developed by using a polyfunctional epoxy resin as the resin itself and further containing a large amount of a filler such as metal powder (Japanese Patent Laid-Open No. 25253/1993 and Japanese Patent Laid-Open No. 25253/1993). No. 112629, JP-A-5-214214).

Further, a structure in which the resin is lined with a metal backing material to support the resin, and the strength of the mold itself is increased, and the thickness of the resin portion is reduced to improve the thermal conductivity, is also proposed. (See Japanese Patent Laid-Open No. 4-129707). In this case, in order to prevent the resin part and the backup material from peeling off (due to the resin part breaking during shrinkage after curing), the backup material has a structure in which a large number of bolts and grooves are provided, so that mechanical bonding is achieved. It has increased strength. On the other hand, a cooling pipe is generally used in which a cooling pipe is provided in the backup material to improve cooling efficiency during molding.

[0005]

However, even in these resin molds, cracks may be formed in the molding surface layer at the stage of curing and cooling at the time of molding the mold, and repetitive stress at the time of molding may cause cracks (particularly on the dividing surface of the mold). Also called a parting line)
In addition to the problem of strength such as peeling of the resin part from the backup material in the vicinity, deformation (drip) of the resin part due to abrasion, etc., and low thermal conductivity of the resin itself, backup to the resin part There is a problem in that the molding efficiency does not improve that much due to the poor thermal conductivity at the bonding interface with the material (which is inferior when the resin part and the backup material are separated).

Further, even in the structure having a large number of bolts and grooves in the backup material, it is necessary to process in many parts in order to obtain sufficient joining strength, which not only requires man-hours and labor but also molding surface. There was also a problem with the thermal conductivity of the layers. Due to such problems, the above-mentioned conventional resin mold still has molding of several tens of thousands of shots, and the absolute amount of difference in thermal expansion between the molding surface layer and the backup material becomes large, and a still larger mold clamping force is required. It has the drawback that it cannot be applied to the type of large articles required.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a resin molding die which has improved durability as a die and improved poor thermal conductivity as compared with a conventional resin die. That is, it is possible to perform molding ranging from several thousand shots to tens of thousands of shots and to apply it to a mold of a large article. That is, according to the present invention, in the molding die made of resin, the molding surface layer is made of a resin containing a filler mainly composed of metal powder, and the molding surface layer is backed and supported by a joint by a metal backing portion. , The difference in the coefficient of thermal expansion between the members constituting the molding surface layer and the metal backing portion is 5
Provided is a resin molding die (first invention) characterized by having a ^{density of x10 -6} / ° C or less. Further, according to the present invention,
A molding die made of a molding surface layer, an intermediate layer and a metal backing part, wherein the molding surface layer and the intermediate layer are each formed of a resin containing a filler mainly containing metal powder, The intermediate layer is backed and supported by a metal backing portion by bonding, and the difference in coefficient of thermal expansion between the members constituting the intermediate layer and the metal backing portion is 5
Provided is a resin molding die (second invention) characterized in that the content of the filler in the molding surface layer is lower than the content of the filler in the intermediate layer while the content is not more than × 10 ^-6 / ° C.

[0008]

In the resin molding die according to the first aspect of the present invention,
The molding surface layer is configured to be backed and supported by the metal backing portion by joining, and the difference in the coefficient of thermal expansion between the members forming the molding surface layer and the metal backing portion is set to a predetermined value or less. That is, the difference in coefficient of thermal expansion between each member constituting the molding surface layer and the metal backing portion at room temperature to 200 ° C. is 5 × 10 ⁻⁶ / ° C. or less, preferably 4 × 10 ⁻⁶ /
C. or less, more preferably 2.times.10.sup.- ⁶ / .degree. C. or less.

If the difference in the coefficient of thermal expansion exceeds 5 × 10 ^-6 / ° C., cracks may occur in the molding surface layer during the steps of hardening and cooling during the manufacture of the mold, and the thermal cycle and repeated stress during molding Due to this, peeling may occur at the joint surface between the molding surface layer and the backing portion, so that the molding surface layer is likely to be cracked. Further, when peeling occurs, there is a problem that the thermal conductivity of the molding surface layer (heat removal ability of the molding surface layer) is also reduced.

In the first invention, it is presumed that the bonding between the molding surface layer and the metal backing portion is mainly chemical bonding. And, in order to effectively achieve and maintain this chemical adhesion, the thermal expansion coefficient of each member constituting the molding surface layer and the metal backing portion as described above is deeply related,
It was discovered that, when the difference in the coefficient of thermal expansion of each member is equal to or less than a specific value, the bonding between the molding surface layer and the metal backing portion can be satisfactorily achieved and maintained for the first time.

In the first aspect of the present invention, as a means for increasing the chemical bond strength in order to more reliably prevent peeling at the joint surface between the molding surface layer and the backing portion, for example, a molding surface layer of the backing portion It is also effective and preferable to apply a coupling treatment to the joint surface in the same manner as the usual adhesion between an epoxy resin and a metal.

The materials for forming the molding surface layer and the metal backing portion are as follows. The molding surface layer is made of a resin containing a filler composed mainly of metal powder, and as a specific material, it is disclosed in JP-A-5-25253.
Japanese Patent Laid-Open No. 5-112629, Japanese Patent Laid-Open No. 21421/1993
Thermosetting epoxy resin (preferably a polyfunctional resin is used from the viewpoint of strength) as shown in Japanese Patent No. 4 etc. contains 50% by weight or more of metal powder or ceramic powder to obtain thermal conductivity. , With reduced thermal expansion while increasing wear resistance (coefficient of thermal expansion is below the level of 30 × 10 ^-6 / ° C)
Is preferred.

Examples of the metal powder include aluminum powder, nickel powder, iron powder, copper powder and alloys thereof. However, considering that the thermal conductivity and the specific gravity are close to those of epoxy resin, aluminum powder or aluminum alloy powder is preferable. The reason why the specific gravity is taken into consideration here is that if there is a large difference in the specific gravity between the resin and the metal powder, the metal powder will precipitate first when the mixture of the resin and the metal powder is cast. (There is also a method of first casting only metal powder and then impregnating it with resin.) As the ceramic powder, oxide type (alumina, silica, zirconia, magnesia, etc., or a mixture thereof), and carbide type, A nitride type is mentioned.

In order to improve wear resistance, it is preferable to add a large amount of ceramic powder. Further, in order to improve machinability, it is preferable to appropriately mix and contain metal powder and ceramic powder. However, in this case, the particle size of the ceramic powder may be smaller than that of the metal powder. In order to allow the resin to contain the above-mentioned metal powder, ceramic powder, or a mixture of both, it is advisable to adjust the individual particle size distribution so that the closest packing can be achieved. The upper limit of the content can also be controlled by the casting method.
Vibration may be used.

The metal backing part is preferably a zinc alloy (coefficient of thermal expansion is 26 to 28 × 10 ^-6 / ° C.). As this zinc alloy, Al: 3.9 to 4.3 wt% and Cu: 2.9, which are generally used as casting alloys, are used.
.About.3.4 wt%, Mg: 0.03 to 0.06 wt%, and a basic composition of residual Zn (trade name: ZAS, manufactured by Mitsui Mining & Smelting Co., Ltd.), but similar Zn-Al A zinc alloy may be used in which the strength is increased by increasing the contents of Cu and Al in a -Cu alloy, or by including Ni, Ti and the like. A combination of such a molding surface layer made of a resin and a backing portion made of a zinc alloy is preferable because the difference in the coefficient of thermal expansion between them becomes small. In addition, providing unevenness on the molding surface layer side surface of the backing part is
It is preferable in order to further increase the bonding strength.

When the molding surface has a convex portion, it is preferable to embed a metal rod or plate in the convex portion in a state of being bonded to the backing portion. At this time, if the rod or plate is provided with irregularities or through holes, the bonding strength is further stabilized. Further, when the convex portion of the molding surface is narrower and higher, it is preferable to insert the same shaped article made of metal to form the molding surface.

The thickness of the molding surface layer is to improve the heat removal capability and to suppress the reaction heat at the time of curing to reduce the heat influence on the model (prototype). Furthermore, the molding surface layer is cast and cured. From the viewpoint of preventing distortion during production, it is preferably thinner, specifically 30 mm or less, more preferably 10 mm or less.
mm or less, and particularly preferably 5 mm or less. However, considering the accuracy of the backing part and the filling property at the time of casting,
1 mm or more is necessary.

In the resin molding die of the first invention, it is preferable that a cooling pipe is embedded in the molding surface layer. Conventionally, in molding, a structure in which a cooling pipe is provided in a backing part for cooling the mold is known, but in the present invention, in order to further enhance the cooling effect of the molding surface, The cooling pipe is embedded in the surface layer. In addition, when a large article or the like and a cooling effect are further required, it is preferable to provide a cooling pipe also in the backing portion from the viewpoint of mold cooling, but it is not particularly essential.

The cooling pipe is pre-bonded to the backing portion, and the molding surface layer is cast between the model and the backing portion to be embedded in the molding surface layer. At this time, the molding surface layer is hardened by applying heat and is bonded (bonded) to the backing portion and the cooling pipe, but in this case, if the backing portion and the cooling pipe are not sufficiently fixed, the heat of the cooling pipe itself Due to the expansion, not only the position of the cooling pipe shifts and becomes inaccurate, but also the stress due to the difference in thermal expansion with the cooling pipe is applied in the molding surface layer,
It may cause peeling during molding. As the material of the cooling pipe, copper is preferable from the viewpoint of workability and thermal conductivity, and it can be joined to the backing portion by welding.

As for embedding the cooling pipe, as shown in FIG. 6, a groove portion 11 is provided on the metal backing portion 2 side at the joint surface between the molding surface layer 1 and the metal backing portion 2, and the groove portion 11 is provided in the groove portion 11. It is further preferable that the cooling pipe 12 is fitted and the cooling pipe 12 is joined and buried by the resin forming the molding surface layer 1. With such a structure, most of the stress generated by the difference in thermal expansion between the cooling pipe and the molding surface layer is absorbed by the backing portion, so that the problem of peeling is solved. In addition, the thickness of the molding surface layer can be made thin and uniform regardless of the diameter of the cooling pipe. Further, since the position of the pipe is also accurate, it is possible to easily perform post-processing such as a mold releasing pin required as a mold. In addition, as the cooling pipe used in the present invention, it is preferable to use a bellows-shaped metal pipe in order to further enhance the cooling efficiency.

When molding is performed using a molding die, the clamping pressure at the time of molding is in a state of being applied to the peripheral portion of the dividing surface of the die. By the way, the clamping pressure is about 10 for large items.
00 tons, medium articles 300 to 500 tons, small articles about 100 tons, and the surface pressure at the peripheral portion of the mold dividing surface is about 400 to 500 kg / cm ² . In such a case, the strength of the resin itself of the molding surface layer cannot withstand the repetition of this pressure, and the repetitive molding may deform or wear the divided surfaces of the molding surface layer, which may eventually cause a problem.

Therefore, in the resin molding die of the present invention, the metal backing portion is exposed at the peripheral portion of the divided surface of the resin molding die, and the pressure at the time of mold clamping during molding is substantially The durability of the mold can be remarkably improved by forming the exposed metal backing portion in the structure. This will be described with reference to the drawings. As shown in FIG. 3, a molding die composed of a molding surface layer 1 made of a resin and a metal backing portion 2 lining and supporting it is
Usually, it is composed of an upper mold 3 and a lower mold 4, and a molding space 5 is formed between the molding surface layers 1 of the upper mold 3 and the lower mold 4. In the preferred embodiment of the present invention, the metal backing portion 2 is exposed at the peripheral portion 6 of the mold dividing surface, and the mold clamping pressure is applied to the peripheral portion 6 of the mold dividing surface.

Further, as shown in FIG. 4, a metal block 7 made of a material having higher durability (hardness) than the backing member material is inserted into the peripheral portion 6 of the mold dividing surface to insert the metal backing portion 2.
It is preferable to join with because the durability of the mold can be improved. For example, when the backing material is a zinc alloy, steel such as carbon steel is used as the metal block.

In the resin molding die having the structure shown in FIGS. 3 and 4, at the die contact surface (contact surface),
It is important to adjust the height direction of the metal surface and the molding surface layer. That is, as shown in FIG. 5, a sufficient mold clamping pressure is applied to the metal backing portion 2 exposed at the peripheral portion 6 of the mold dividing surface, and the molded product is fed from the parting line 8 of the molding surface layer portion. In order to prevent burrs from occurring, the gap A of the metal contact surface 9 becomes substantially 0 and the gap B of the parting line 8 of the molding surface layer portion is 0.05 m when the molds are fitted together.
It is preferably m or less.

In this case, the gap A between the metal contact surface 9 and the gap B between the parting lines 8 is more preferably 0, but the metal backing portion (including the case where a metal block is inserted) and the molding surface are also included. Considering the difference in elastic modulus from the layer portion (metal is approximately 10 times or more that of the resin forming the molding surface layer), after the gap B becomes 0, the elastic deformation range of the molding surface layer portion It is more preferable that the clearance A be zero by the tightening force. Specifically, although it depends on the elastic modulus of the molding surface layer, it is preferable that the clearance A be about 0.05 mm when the clearance B is zero.

As shown in FIG. 5, in the resin molding die of the present invention, the provision of the collar portion 10 as the molding surface layer 1 can suppress deformation and wear of the molding surface layer 1 due to repeated molding, preferable. In this case, the thickness C of the collar portion 10
Is preferably 20 mm or more because the elastic allowable range is increased. The width D of the collar portion 10 is preferably 10 mm or more so that the molding surface layer 1 and the metal backing portion 2 do not apply stress in the shearing direction during mold clamping, but the pressure is effectively applied to the metal portion. 30mm to receive
The following is more preferable.

Next, the resin molding die according to the second aspect of the present invention will be described. The molding die of the second invention has a three-layer structure of a molding surface layer, an intermediate layer, and a metal backing portion, and the molding surface layer and the intermediate layer each contain a filler mainly containing metal powder. And an intermediate layer is backed and supported by a metal backing by joining. And, the difference in the coefficient of thermal expansion between room temperature and 200 ° C. of the members constituting the intermediate layer and the metal backing part is 5 × 10 ⁻⁶ / ° C. or less, preferably 4 × 10 ⁻⁶ / ° C. or less, and further preferably The content of the filler in the molding surface layer is set lower than 2 × 10 ⁻⁶ / ° C. and lower than the content of the filler in the intermediate layer.

In order to obtain a good bonding state between the resin layer and the metal backing by setting the difference in thermal expansion coefficient between them to 5 × 10 ⁻⁶ / ° C. or less, and to improve the thermal conductivity, the main component is metal powder. It is necessary to make the resin contain a large amount of the filler. Specifically, the content of the filler is preferably 45% or more, more preferably 55% or more, still more preferably 65% or more in terms of area ratio. If aluminum filler powder is used as the filler, the weight is In the respective ratios, about 55% or more, 65% or more, and 75% or more are contained.
When the resin containing a large amount of this filler is directly used as the molding surface layer as in the above-mentioned first invention, it is difficult to obtain a glossy molding surface due to poor polishing characteristics only at the time of finishing, and an increase in the number of molding shots. Along with this, the molding surface may be roughened, which may cause a problem in the moldability of the product.

Therefore, in the second invention, the resin containing a large amount of the filler as described above is used as the intermediate layer to ensure a good joining state between the metal backing portion and the resin layer, and The moldability is improved by providing a molding surface layer on the intermediate layer using a resin having a filler content lower than that of the intermediate layer while increasing the thermal conductivity. As described above, when a resin having a low filler content is used for the molding surface layer, the glazing property is improved only at the time of mold finishing and a glossy surface is easily obtained, and the roughening of the molding surface due to an increase in the number of molding shots is also suppressed. To be done.

The filler content of the resin used in the molding surface layer is preferably 40% or less, more preferably 30% or less in terms of area ratio.
More specifically, the exposed area of the filler on the polishing target surface (the surface of the molding surface layer) is 3 times the total area of the polishing target surface.
It is desirable that the resin be 0% or less. The resin used for the molding surface layer is preferably one that can be primary cured at room temperature. The molding surface layer is usually formed by gel-coating the resin used for this on a model coated with a release agent by brush coating and curing, but if the curing treatment is quickly performed at room temperature, it is cured. No problems occur on the transfer surface due to expansion or ejection of air contained in the model during processing.

The thickness of the molding surface layer is preferably 0.1 to 2.0 mm, from the viewpoints of not lowering the thermal conductivity, ensuring workability in forming the molding surface layer, and ensuring thickness uniformity. More preferably, it is 0.1 to 1.0 mm. Here, the reason why the thickness of the molding surface layer is 2.0 mm or less is to prevent a decrease in thermal conductivity in the molding surface layer, and it is more effective if it is 1.0 mm or less. Also, on the production side, when gel-coating the model for the molding surface resin with a brush,
If the brush coating operation is repeated many times, the release agent applied to the model in advance will easily come off. In order to avoid this, when the brush coating is performed as few times as possible, for example, once, the thickness of the molding surface layer is about 0.5 mm. Also,
The resin applied to the model by brush coating tends to be thin at the vertical wall portion of the model and thick at the concave bottom portion due to sagging after application. This tendency becomes more remarkable as the thickness of the resin applied to the model becomes larger, and such a difference in thickness causes a difference in heat generation due to a reaction at the time of curing, which may cause shape distortion and surface roughness. Become. In order to make the thickness as uniform as possible and prevent the occurrence of such defects, it is preferable to suppress the thickness of the molding surface layer to about 2.0 mm.
Further, in order not to reduce the thermal conductivity, it is preferable to suppress the total thickness of the molding surface layer and the intermediate layer to 5 mm or less.
If these resin layers are too thick, heat conduction as a mold is deteriorated, which leads to problems such as deterioration of quality of molded products and lengthening of molding cycle.

Also in the molding die of the second invention, it is possible to embed the cooling pipe in the intermediate layer by the same means as the embedding of the cooling pipe in the molding surface layer in the above-mentioned first invention. In terms of Also, like the first invention,
By exposing the metal backing part in the peripheral part of the dividing surface of the molding die, the pressure at the time of mold clamping at the time of molding is formed to a structure that is applied to the exposed metal backing part, By inserting a metal block into the peripheral part of the dividing surface of the mold and joining it with the metal backing part, the pressure at the time of mold clamping during molding is formed so as to substantially affect the metal block. It is possible to improve the durability of the mold. In the second invention, the description regarding the molding surface layer and the metal backing in the first invention described above can be applied to the materials constituting the intermediate layer and the metal backing portion, the means for increasing the bonding strength, and the like. .

[0033]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited to these examples.

(Example 1) Box shape (dimensions: 750 x 4)
A molding die for manufacturing a molded product of 50 × 250 (height) mm) was manufactured by the method shown in FIG. 7 and evaluated. First, a model (wooden mold) 14 having a surface that reflects the shape of a molded product, a zinc alloy backing 2 having a wall thickness of the molding surface layer 1 and a space corresponding to a width of 30 mm in the peripheral portion 6 of the split surface. (Coefficient of thermal expansion 26 × 10 ⁻⁶ / ° C.,
Product name: ZAS, covered with Mitsui Mining & Smelting Co., Ltd.
On the molding surface layer side of this backing 2, the width and depth are 10 m.
m groove 11 is provided, and a copper pipe 12 is fitted into the groove 11.

Next, in the space formed by the model 14 and the backing 2, a composite resin material 15 (coefficient of thermal expansion 28 × 10 ⁻⁶ /
C., brand name: MYX-06, manufactured by Mitsubishi Petrochemical Co., Ltd. was cast from the injection container 16 while applying a pressure of about 1 atm. It should be noted that the backing 2 has an air vent 17 communicating with the groove 11.
Was set up. After casting, heat the whole body to 50 ° C once to primary cure the surface layer and release the model (prototype).
The molding surface layer 1 was formed by performing a secondary curing treatment at 3 ° C. for 3 hours to obtain a molding mold (upper mold) 3 shown in FIG. At this time, no problem such as peeling or cracking of the molding surface layer 1 occurred.

(Example 2) The same as Example 1 except that MYX-05 (trade name, manufactured by Mitsubishi Petrochemical Co., Ltd.) having a thermal expansion coefficient of 30 × 10 ^-6 / ° C. was used as the composite resin material. Then, a molding die (upper die) 3 shown in FIG. 1 was obtained. At this time, no problem such as peeling or cracking of the molding surface layer 1 occurred.

(Comparative Example 1) An aluminum alloy (coefficient of thermal expansion: 21 x 10) was used for the backing portion in the same manner as in Example 1.
^When a product formed at ⁻⁶ / ° C., JIS AC4C) was manufactured, a crack was generated in the central portion of the molding surface layer after the secondary curing treatment. Further, peeling was also confirmed in part at the boundary between the molding surface layer portion and the backing portion in the peripheral portion of the mold dividing surface.

(Embodiment 3) By the same method as in Embodiment 1, a groove for a cooling pipe is not provided on the molding surface layer side of the backing portion 2, and the composite resin material is also backed on the peripheral portion 6 of the mold dividing surface. A molding die 3 was obtained under the same conditions as in Example 1 including the alloy material and the composite resin material, except that the molding die 3 was formed so as to cover the end face portion of the portion 2. After that, cooling holes 13 were provided in the backing portion 2 to obtain the molding die 3 having the structure shown in FIG.

(Example 4) Interior parts for automobiles (Dimension: 6)
A molding die for manufacturing a molded product of 00 × 400 × 200 (height) mm) was manufactured by the method shown in FIG. 9 and evaluated. First, a model (wooden mold) 14 having a surface that reflects the shape of a molded product is used, and a composite resin material (coefficient of thermal expansion: 36 × 10 ⁻⁶ / ° C.) for a molding surface layer composed of a filler mainly composed of metal powder and a resin. , Trade name: MEZ500G, manufactured by Zeon Rise Co., Ltd., was gel-coated by brush coating to a thickness of 0.5 mm to form a molding surface layer having a filler content of about 30 area%. After gelling, the backing 2 made of zinc alloy (thermal expansion coefficient 26 × 10 ⁻⁶ / ° C., trade name: ZAS, having a thickness of 4.5 mm of the intermediate layer and a space corresponding to a width of 20 mm in the peripheral portion of the dividing surface, Covered with Mitsui Mining & Smelting Co., Ltd. A groove 11 having a width and a depth of 10 mm is provided on the intermediate layer side of the backing 2, and a copper pipe 12 is fitted into the groove 11.

Then, in the space formed by the gel coat 19 and the backing 2 on the model 14, the composite resin material 1 for the intermediate layer, which is composed mainly of filler and resin mainly composed of metal powder.
5 (manufactured by Mitsubishi Petrochemical Co., Ltd., trade name: MYX-06 (coefficient of thermal expansion: 28 × 10 ⁻⁶ / ° C.)) was further increased by 10% by weight of an aluminum alloy powder having an average particle size of 20 μm.
5% filler content) was cast from the injection container 16 while applying a pressure of about 2 atm. The backing 2 was provided with an air vent 17 communicating with the groove 11. After casting, the whole surface is once heated to 50 ° C. to primary cure the surface layer, the model (prototype) is released, and then secondary curing is performed at 120 ° C. for 3 hours to form an intermediate layer. A molding die (upper die) 3 shown in 8 was obtained. At this time, peeling of the intermediate layer 20,
No problems such as cracking occurred.

(Evaluation) In each of Examples 1 to 4, a core molding die (lower die) 4 was manufactured by the same method, using a model (prototype) reflecting the back side shape of a desired molded article. Then, an assembling process with the molding die (upper die) 3 created in Examples 1 to 3 was performed to mold the molded product 18 with the ABS resin. Regarding the molds of Examples 1 and 2,
In the state where the molds are matched, the metal contact surface 9 and the parting line 8 in the molding surface layer portion are processed so that the clearance between them is 0.

(Molding Result) In the molding die of Example 3, 5
It was possible to repeat molding up to the stage of 000 shots. After that, wear was generated on the divided surface of the mold and burrs were generated on the molded product, so the molding was stopped. It was found that the molding dies of Examples 1 and 2 did not cause burrs on the molded products even after repeated molding of 10,000 shots, and that the molding cycle was improved by about 20% as compared with the molding dies of Example 3. . Also, comparing the molding dies of Example 1 and Example 2,
After repeated molding of 10,000 shots, in Example 2, slight peeling was confirmed at the boundary between the molding surface layer portion and the backing portion in the peripheral portion of the mold dividing surface.
Then there was no problem. In the molding die of Example 4, burrs did not occur in the molded product even after repeated molding of 10,000 shots as in Examples 1 and 2, and the molding cycle was the same as that of Example 1.
It was possible to achieve a level almost equal to that of a general metal mold by further shortening by 20% as compared with the above.

[0043]

As described above, according to the resin molding die of the present invention, the durability can be improved and the poor thermal conductivity can be improved. Therefore, the use of this resin molding die has an excellent effect that molding can be performed for several thousand shots to tens of thousands of shots and application to a die for large articles.

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram showing an example of the structure of a resin molding die of the present invention (first invention).

FIG. 2 is a cross-sectional configuration diagram showing another example of the structure of the resin molding die of the present invention (first invention).

FIG. 3 is a partial cross-sectional view showing an example in which a metal backing portion is exposed at the peripheral portion of the dividing surface of the molding die according to the present invention (first invention).

FIG. 4 is a partial cross-sectional view showing an example in which a metal block is inserted into the peripheral portion of the divided surface of the molding die according to the present invention (first invention) and joined to the metal backing portion.

FIG. 5 is an explanatory diagram showing a state of a gap between a metal contact surface and a parting line of a molding surface layer portion in a mold matching state.

FIG. 6 is a partial explanatory view showing an example in which a cooling pipe is fitted in a groove portion provided on the metal backing portion side.

FIG. 7 is a schematic explanatory view showing an example of a method for producing the resin molding die of the present invention (first invention).

FIG. 8 is a cross-sectional configuration diagram showing an example of the structure of a resin molding die of the present invention (second invention).

FIG. 9 is a schematic explanatory view showing an example of a method for producing a resin molding die of the present invention (second invention).

[Explanation of sign]

1 molding surface layer, 2 metal backing part, 3 upper mold (molding mold), 4 lower mold (molding mold), 5 molding space, 6
Periphery of mold dividing surface, 7 metal block, 8 parting line, 9 metal contact surface, 10 collar part, 11
Grooves, 12 cooling pipes, 13 cooling holes, 14 models, 15 composite resin materials, 16 injection containers, 17 air vents, 18 molded products, 19 gel coats, 20 intermediate layers.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiaki Ishihara 2-56 Suda-cho, Mizuho-ku, Nagoya, Aichi Prefecture

Claims (6)

[Claims] 1. A molding surface made of resin, wherein the molding surface layer is made of a resin containing a filler mainly composed of metal powder, and the molding surface layer is backed and supported by a metal backing portion by bonding. A resin molding die, wherein a difference in coefficient of thermal expansion between members constituting the layer and the metal backing portion is 5 × 10 ⁻⁶ / ° C. or less. 2. The resin molding die according to claim 1, wherein a cooling pipe is embedded in the molding surface layer. 3. A groove is provided on the metal backing portion side at a joint surface between the molding surface layer and the metal backing portion, a cooling pipe is fitted in the groove portion, and cooling is performed by a resin forming the molding surface layer. The resin molding die according to claim 1, wherein the pipes are joined and embedded. 4. A structure in which a metal backing portion is exposed at a peripheral portion of a divided surface of a resin molding die, and pressure during mold clamping during molding is substantially applied to the exposed metal backing portion. The resin molding die according to claim 1, wherein the resin molding die is formed. 5. A metal block is inserted into a peripheral portion of a divided surface of a resin molding die to be joined to a metal backing portion, and the pressure at the time of mold clamping during molding is substantially the same as that of the metal mold. The resin molding die according to claim 1, wherein the resin molding die is formed to have a structure of a block. 6. A resin molding die comprising a molding surface layer, an intermediate layer and a metal backing part, wherein the molding surface layer and the intermediate layer each contain a filler mainly containing metal powder. The intermediate layer is made of a resin, and the intermediate layer is backed and supported by a metal backing portion by joining. The difference in coefficient of thermal expansion between the members forming the intermediate layer and the metal backing portion is 5 × 10 ^−6. / ° C. or less, and the content of the filler in the molding surface layer is lower than the content of the filler in the intermediate layer.