JP2003211411A - Cork product and method for manufacturing cork product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a new structured cork product capable of improving a touch of the cork in the cork product. <P>SOLUTION: After filling a molding material 14 wherein a granular cork material 12 is mixed in a heat melted synthetic resin material 10 into a specific molding cavity by a specific pressure, the molding material 14 is solidified by cooling by allowing a specific amount of expansion of the molding material 14 based on spring buck of the cork material 12. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a cork product and a method for producing a cork product, and in particular, while keeping the original texture of cork,
The present invention relates to a new cork product that can be easily manufactured with various shapes and a method for manufacturing a new cork product.

[0002]

BACKGROUND ART As is well known, cork is a plant substance obtained from cork tissue of cork oak, and based on its unique tissue structure and composition, (1) has a large elasticity and is lightweight. (2) High impermeability to liquids and gases,
(3) Heat, sound, vibration, etc. are small in transmission rate, (4) High abrasion resistance, (5) High antibacterial property, and (6) Flame retardant properties can be exhibited. Conventionally, for example, in addition to building materials such as flooring materials and wall materials, their use in footwear, ball cores for ball games, interior materials, etc. has been studied.
In addition, products using cork are roughly classified into single products such as cork stoppers and agglomerated products such as flooring, and both are subjected to boiling treatment after leaving the collected cork oak bark in the open air for a predetermined period of time. It will be manufactured using the cork material for processing obtained by leaving it in the open air.

By the way, in the production of agglomerated cork products, in general, fragment-cut or granulated agglomerated cork bodies are used, and a suitable amount of synthetic resin is mixed with the agglomerated cork bodies to obtain a molding material. Then, the molding material is filled in a molding cavity of an appropriate molding die, and press molding is performed through heating, cooling, and solidifying steps to obtain a block-shaped aggregated cork molded body. Also,
For thin-walled products such as flooring, the final agglomerated cork molded body is sliced into an appropriate thickness to obtain the final product shape.

However, in such a press molding method,
Basically, it is difficult to manufacture an aggregated cork molded product having a shape other than the substantially block shape, and in addition, there is a problem that the molding cycle is long and mass production cannot be expected.

Incidentally, Japanese Patent Application Laid-Open No. 7-323098 proposes a method of manufacturing a product made of a composite material of cork material and synthetic resin material by injection molding. However, when the cork material and the synthetic resin material are mixed and the synthetic resin material is heated and melted and then injection-filled into the molding cavity, defective filling at the time of molding is prevented and molding defects such as sink marks and voids in the molded product are prevented. Since it is necessary to apply a sufficient injection pressure in order to avoid the above, the cork material is compressed by the injection pressure at the time of molding. Then, the synthetic resin material is cooled and solidified in the molding cavity in a state where the cork material is compressed by the action of the injection pressure or the coercive force. In most cases, the texture is lost, resulting in a product made of a material that is close to a hard synthetic resin material. Therefore, the injection molding method proposed in the above publication is used for manufacturing cork products. The method was not always effective.

[0006]

The present invention has been made in view of the above circumstances, and a problem to be solved by the present invention is that the cork material is formed from a composite material of a cork material and a synthetic resin material. It is to provide a cork product having a new structure that can be easily manufactured with stable quality while retaining the texture of the above, and a new manufacturing method for such a cork product.

[0007]

Aspects of the present invention made to solve such problems will be described below. The constituent elements used in each of the following aspects can be used in any combination as much as possible. Further, the aspects and technical features of the present invention are not limited to those described below, but are described in the entire specification and the drawings, or the invention idea that can be understood by those skilled in the art from those descriptions. It should be understood that it is recognized based on this.

First, the first aspect of the present invention relating to a method for producing a cork product is to fill a molding cavity at a predetermined pressure with a molding material prepared by mixing a heat-melted synthetic resin material with a granular cork material, A method for producing a cork product, which allows a predetermined amount of expansion of the molding material based on springback of the cork material to allow the molding material to cool and solidify.

According to such a manufacturing method of this aspect, the pressure exerted on the molding material filled in the molding cavity can be reduced, and when the molding material is filled in the molding cavity. It is possible to cool and solidify the molding material in a state where the compression deformation of the cork material that has been compressed and deformed by pressure is reduced or released, and by doing so, the cork structure such as cork oak and Abbemaki is carved out. It is also possible to manufacture a cork product having a texture close to that of a cork product.

According to the manufacturing method of this embodiment, after the molding material is filled in the molding cavity at a predetermined pressure,
Since a predetermined amount of expansion of the molding material is allowed, by setting the filling pressure to a large value to prevent defective filling of the molding material into the molding cavity, molding defects such as sink marks and voids can be avoided, and In addition to improving accuracy and quality, the cork material expands and restores in the molding cavity while maintaining the filling state of the molding material in the molding cavity, resulting in a cork product that expresses the texture of cork. It can be provided.

Further, according to the manufacturing method of the present embodiment, since the cork product is manufactured by filling the molding cavity with the molding material, the molding die having the molding cavities of various shapes is prepared. It is possible to easily manufacture a cork product having a shape that is difficult to achieve by carving from the cork.

In the manufacturing method of this embodiment, filling with a predetermined pressure means that a predetermined pressure is applied when the molding material is filled in the molding cavity, and that the molding material is filled with the predetermined material after filling the molding cavity. Including both cases of exerting pressure.

Further, in the manufacturing method of the present embodiment, the molding material in which the granular cork material is mixed with the synthetic resin material which is heated and melted is a synthetic resin material which is obtained by mixing the unmelted synthetic resin material and the cork material. Heat-melted, heat-melted synthetic resin material mixed with granular cork material, or heat-melted synthetic resin material and cork material kneaded into pellets and heat-melted again Any of the above can be adopted.

A second aspect of the present invention relating to a method for producing a cork product is the same as the method for producing a cork product according to the first aspect, in which (a) fixed metal pieces are arranged to face each other so that they can be displaced toward and away from each other. With the mold and movable mold clamped,
A primary mold clamping step of forming a molding cavity between the mold mating surfaces of the fixed mold and the movable mold; and (b) heating the synthetic resin material to the molding cavity formed in the primary mold clamping step. An injection step of injecting and filling the molding material obtained by melting and mixing the granular cork material; and (c) filling the molding cavity with the molding material in the injection step, and then moving the fixed mold and the movable mold. A secondary mold clamping step of increasing the volume of the molding cavity by retracting at least one part or all of the mold in the separating direction.

According to such a manufacturing method of this embodiment, the molding material can be filled into the molding cavity advantageously and promptly by utilizing the injection pressure, whereby the desired cork product can be obtained. The manufacturing efficiency of can be improved.

A third aspect of the present invention relating to a method for producing a cork product is the method for producing a cork product according to the second aspect, wherein the synthetic resin material and the granular cork material that have been heat-melted are kneaded. And forming a pellet-shaped mixed material in advance by cooling and solidifying, heating and melting the mixed material in the injection step, and injection filling the molding cavity as the molding material,
Characterize. According to such a manufacturing method of the present embodiment, it becomes possible to reduce or prevent the uneven distribution of the cork material in the cork product caused by the difference in the specific gravity of the cork material and the synthetic resin material, It is possible to stably mass-produce the cork product in which the distribution of the cork material is substantially uniform over the entire cork product.

A fourth aspect of the present invention relating to a method for producing a cork product is the method for producing a cork product according to the second or third aspect, wherein an in-line screw provided with a heating cylinder in the injection step. The molding material is injection-filled into the molding cavity by using a conventional injection device. According to such a manufacturing method of the present embodiment, the synthetic resin material can be heated and melted in the heating cylinder of the injection device and the granular cork material can be kneaded with the synthetic resin material before the injection of the molding material. Therefore, the synthetic resin material and the granular cork material can be simply and efficiently mixed.

A fifth aspect of the present invention relating to a method for producing a cork product is the method for producing a cork product according to any one of the second to fourth aspects, wherein the injection pressure of the molding material in the injection step is adjusted. It is characterized in that the pressure is 18 to 160 MPa. According to the manufacturing method of this aspect, the molding material can be stably filled in the molding cavity, and the composite integration of the cork material and the synthetic resin material can be realized with high strength. That is, when the injection pressure is lower than 18 MPa, it is difficult to stably fill the molding cavity with the molding material, and it may be difficult to sufficiently exhibit the integral strength of the cork material and the synthetic resin material. On the other hand, if the injection pressure is higher than 160 MPa, the compressive deformation of the cork material due to the injection pressure may not be sufficiently recovered, and the quality of the cork product may deteriorate. The injection pressure is more preferably 20 to 120 MPa.

Further, a sixth aspect of the present invention relating to a method for producing a cork product is the method for producing a cork product according to any one of the first to fifth aspects, wherein in the molding material, the synthetic resin material is: The mixing ratio of A and the cork material: B is B / A = 0.4 to 4 in weight ratio. According to such a manufacturing method of the present embodiment, it becomes possible to bring the synthetic resin material and the cork material into a uniform mixed state, whereby the texture and strength of the cork in the cork product can be more advantageously obtained. It will be possible. That is, B
When the value of / A is less than 0.4, it becomes difficult to obtain a sufficient cork texture in a cork product, and it becomes difficult to inject a synthetic resin material and a cork material in a uniform mixed state. , B / A greater than 4, it becomes difficult to secure the adhesive force of the synthetic resin material to the cork material, and it may be difficult to obtain sufficient strength in the cork product. The weight ratio B / A of the mixing ratio of the synthetic resin material and the cork material is more preferably 0.6 ≦ B / A ≦ 1.5.

A seventh aspect of the present invention relating to a method for producing a cork product is the method for producing a cork product according to any one of the first to sixth aspects, wherein the molding material is filled in the molding cavity. After that, the volume of the molding cavity is increased by 5 to 30%. According to such a manufacturing method of this aspect, the texture of cork in a cork product can be more advantageously exhibited. That is, when the increase in the volume of the molding cavity is smaller than 5%, it is difficult to sufficiently release the compression deformation of the cork material due to the injection pressure, and therefore the texture of cork in the cork product is not sufficiently expressed. There is a risk that the volume of the molding cavity will increase by 3
This is because if it exceeds 0%, voids may be generated in the molding cavity to reduce the dimensional accuracy of the molded product obtained, or molding defects may occur. The increase in the volume of the molding cavity is more preferably 10 to 20.
%.

In addition, the increase in the volume of the molding cavity in the manufacturing method of the present embodiment is, for example, that the molding cavity is formed between the mating surfaces of a pair of molding dies which are arranged to face each other so that they can be displaced / separated from each other. In some cases, this can be advantageously done by moving at least one of the pair of molding dies or a part thereof in the separating direction.

An eighth aspect of the present invention relating to a method for producing a cork product is the method for producing a cork product according to any one of the first to seventh aspects, wherein the molding material is cooled in the molding cavity. After the solidification, the molded product taken out from the molding cavity is subjected to a surface layer removing step of removing at least a part of the surface layer of the molded product by polishing or the like. According to such a manufacturing method of the present embodiment, the synthetic resin material that covers the surface of the cork material positioned near the surface of the cork product is removed, whereby the cork material is attached to the surface of the cork product. Being exposed, the texture of cork in a cork product can be more advantageously exhibited.

Further, the present invention is manufactured by the method for manufacturing a cork product according to any one of the first to eighth aspects, and is formed by the molding material made of a mixture of the synthetic resin material and the cork material. Cork products that are used with the exposed surface directly exposed to the outside are also featured. In such a cork product, since the surface of the cork material is directly exposed to the outside, it is possible to realize a texture close to that of a cork product made by cutting out from natural cork.

[0024]

Embodiments of the present invention will now be described in detail with reference to the drawings in order to more specifically clarify the present invention.

First, FIG. 1 shows a schematic process diagram of a method for producing cork brick as a first embodiment of the present invention. The cork brick manufacturing method is as follows. A molding material 14 in which a synthetic resin material 10 melted by heating and a cork particle 12 as a granular cork material are mixed is filled in a molding cavity 16 at a predetermined pressure, and then the cork particles are filled. The molding material 14 is allowed to expand by a predetermined amount due to the spring back of the molding material 12, and the molding material 14 is cooled and solidified.

More specifically, first, as shown in FIG. 1A, the movable mold 20 is aligned with the fixed mold 18 and a predetermined space is provided between the two molds 18, 20. By applying the mold clamping force of (1), the primary mold clamping step of forming the molding cavity 16 having a shape corresponding to the target molded product (cork brick 42) between the mold matching surfaces of the two molds 18, 20 is performed.

This fixed mold 18 has a structure in which a fixed mold body 22 is provided with a cavity forming recess 24. On the other hand, the movable mold 20 includes a movable mold body 26 and a moving core 28. The movable mold body 26 is
The cavity forming through-hole 30 is provided to extend straight in the thickness direction, that is, in the mold opening / closing direction of the fixed mold 18 and the movable mold 20 in a substantially constant cross section. Also,
The axial direction of the through hole 30 for forming the cavity (see FIG.
(A) Middle and left / right direction) A step surface 32 is formed in the middle portion, so that the sectional shape on one side in the axial direction, that is, the fixed mold 18 side is smaller than the sectional shape on the other side in the axial direction. Has also been made smaller. On the other hand, the moving core 28 includes a moving core body 34 that extends straight with a sectional shape slightly smaller than the sectional shape of the cavity forming through hole 30 on the fixed mold 18 side. A stopper portion 36 having a cross-sectional shape slightly smaller than the cross-sectional shape of the cavity forming through hole 30 on the side opposite to the fixed mold 18 side is integrally formed on one side in the direction (left side in FIG. 1A). ing. The movable core 20 is configured by accommodating and arranging the movable core 28 in the cavity forming through hole 30 provided in the movable mold main body 26.
Are movable relative to the movable mold body 26. In addition, the movable core 28 is moved relative to the movable mold body 26 until the stopper portion 36 provided on the movable core 28 is brought into contact with the step surface 32 provided on the movable mold body 26. At the movable core 28, the movable core body 34 protrudes from the movable core body 34.
The cavity forming through hole 30 and the cavity forming concave portion 24 of the fixed mold 18 form the molding cavity 16 when the molding material 14 is injected and filled.

In the mold clamping as described above, generally, the movable plate on which the movable mold 20 is mounted is opposed to the fixed plate on which the fixed mold 18 is mounted so as to be relatively displaceable in the approaching / separating direction. It can be carried out according to a known method by using a mold clamping device equipped with an actuator for mold opening / closing and mold clamping such as a hydraulic type or an electric type.

Then, under such a state that the mold clamping force is exerted, as shown in FIG. 1B, the nozzle portion 38 of the heating cylinder of the injection device in which the fixed mold 18 is nozzle-touched.
Then, an injection step of injecting the molding material 14 which has been heated and melted at a predetermined injection pressure at a predetermined injection pressure into the molding cavity 16 through the resin passage 40 of the fixed mold 18 and filling the molding material 14 is performed. There, in the present embodiment, the injection pressure of the molding material 14 is preferably 18 to 160 MP.
a, more preferably 20 to 120 MPa.
The diameter of the nozzle portion 38 is 2 to 15 mm, preferably 3 to 10 in consideration of the type of the synthetic resin material 10, the particle size of the cork grains 12, the size of the target cork brick 42, and the like.
set to mm. That is, the diameter of the nozzle portion 38 is 2 mm
If it is smaller than 15 mm, problems such as heat generation may occur during continuous molding, and if it is larger than 15 mm, problems such as drawing (resin dripping) from the nozzle portion 38 between shots may occur. . Further, the diameter of the nozzle portion 38 may be larger or smaller than the particle diameter of the cork particles 12. There, cork grain 12
When the nozzle portion 38 having a diameter smaller than the particle size of 10 is adopted, the cork particles 12 that have been compressed and deformed by the injection pressure can be further compressed and deformed. Further, the temperature of both molds 18 and 20 is set to a temperature at which the quality of the cork brick 42 is not deteriorated due to burning of the cork grains 12.

Further, as the molding material 14, cork grains 1
2 and the synthetic resin material 10 are mixed, the synthetic resin material 10 is heated and melted, the heat-melted synthetic resin material 10 and the cork grains 12 are kneaded, and pelletized, which is heated and melted again. ing.

More specifically, as the cork particles 12, a cork material crushed by a crusher or the like, cork shavings, etc. are employed, and the particle size thereof is preferably 0.5 to 30.
mm, more preferably 2.0 to 10 mm.
Further, the water content of the cork grains 12 is desirably 7% or less, whereby the molding cavity 1
The separation of the cork grains 12 and the synthetic resin material 10 at 6 can be advantageously prevented. On the other hand, the synthetic resin material 10 is made of a known thermoplastic resin such as ethylene, propylene, polyethylene, polyurethane resin, polypropylene, polyamide, vinyl chloride, ABS, etc., and scrap generated during injection molding work is crushed by a crusher. Crushed ones, or
Any pelletized material or the like can be adopted.
The mixing ratio of the weight of the synthetic resin material 10: A and the weight of the cork particles 12: B: B / A is preferably 0.4 to 4,
More preferably, the synthetic resin material 10 and the cork particles 12 are mixed so as to be 0.6 to 1.5, and the mixture is placed in a hopper provided in an extruder. The cork grains 12 and the synthetic resin material 10 that have fallen from the hopper to the screw fall into the valleys sandwiched by the flight of the screw, and are transferred in the nozzle direction by the rotation of the screw. While being heated and melted by the band heater from No. 3, the screw is kneaded with the cork grains 12. The cork granules 12 and the synthetic resin material 10 kneaded by the screw are shaped by a die attached to the nozzle and continuously discharged into the space to be cooled and solidified. When pelletized, it is pelletized by a pelletizer attached to the die.

The mixed material of the cork particles 12 and the synthetic resin material 10 pelletized in this way is introduced into the heating cylinder from the hopper provided in the injection device, and is heated and melted again by the heating cylinder to form the molding material. 14 Here, in the present embodiment, an in-line screw type injection device is adopted, and even before the injection of the molding material 14, the molding material 14 is kneaded, that is, the cork particles 12 and the synthetic resin material 10 are kneaded. As a result, uneven mixing of the cork particles 12 and the synthetic resin material 10 can be advantageously prevented. The temperature at which the synthetic resin material 10 is heated and melted when the mixed material is made, and the temperature at which the mixed material is heated and melted, that is, the temperature when the synthetic resin material 10 contained in the mixed material is heated and melted to form the molding material 14 Is appropriately set and changed depending on the adopted synthetic resin material 10, but is set to a temperature at which the quality of the cork brick 42 is not adversely affected by burning of the cork grains 12 or the like.

After the molding cavity 14 is filled with the molding material 14 as described above, as shown in FIG. 1C, the movable core 28 is fixed to a fixed mold by an actuator (not shown) of hydraulic type or electric type. 18 and the volume of the molding cavity 16 is preferably 5 to 50 mm.
A secondary mold clamping step of increasing by 30%, more preferably 10-20% is performed. That is, since the molding material 14 containing the cork particles 12 in a state of being compressed and deformed by the injection pressure is filled in the molding cavity 16, the molding cavity 16 is molded by increasing the volume of the molding cavity 16 as described above. The pressure exerted on the material 14 can be reduced, and a predetermined amount of expansion of the molding material 14 due to the springback of the cork particles 12 is allowed, and as a result, the cork particles 12 are compressed. The molding material 14 can be cooled and solidified without being deformed. As is clear from this, in the present embodiment, the outer shape of the cork brick 42 corresponds to the shape of the molding cavity 16 whose volume is increased.

Here, as a mechanism for controlling the volume increase of the molding cavity 16 in this embodiment, for example, a mechanism for controlling the moving distance of the moving core 28 or a core tightening force by hydraulic pressure applied to the moving core 28 or the like is used. (Driving force)
A mechanism for controlling the moving core 28, a mechanism for defining the moving distance of the moving core 28 by a stopper mechanism, or the like can be adopted.

Then, in a state where the volume of the molding cavity 16 is increased, the molding material 14 filled in the molding cavity 16 is cooled and solidified, and then the mold is opened, and the molded product is released and taken out. Thus, the cork brick 42 as shown in FIG. 2 can be obtained. Subsequently, by performing a surface layer removing step of removing the surface layer formed by the synthetic resin material 10 adhered to the surface of the cork brick 42 by polishing or the like, the cork positioned near the surface of the cork brick 42. The grains 12 are exposed on the surface of the cork brick 42.

According to the method for producing cork bricks as described above, the volume of the molding cavity 16 is increased after the molding material 14 is injected and filled into the molding cavity 16, so that the molding material filled in the molding cavity 16 is increased. 14
The pressure exerted on the molding material 14 can be reduced, and a predetermined amount of expansion of the molding material 14 based on the springback of the cork grains 12 that has been compressed and deformed by the injection pressure of the molding material 14 is allowed. As a result, the molding material 14 can be cooled and solidified in a state where the compression deformation of the cork grains 12 is reduced or prevented, and the texture of the cork of the cork brick 42 is close to that of natural cork. You can do it.

Further, in the present embodiment, since the molding material 14 is filled with the predetermined injection pressure into the molding cavity 16 and a predetermined amount of expansion of the molding material 14 is allowed, the injection pressure is set to a large value and molding is performed. Molding cavity 1 for material 14
By preventing the filling failure in 6, the molding defects such as sink marks and voids can be avoided, the accuracy and quality of the cork brick 42 can be improved, and the filling state of the molding material 14 into the molding cavity 16 can be improved. Mold cavity 1 while keeping
By expanding and restoring the cork grains 12 in 6, it is possible to provide the cork brick 42 in which the texture of the cork is expressed.

Further, in this embodiment, as the molding material 14, the cork granules 12 and the synthetic resin material 10 which have been mixed and heated to be pelletized in advance are heated and melted. And the synthetic resin material 1 due to the different specific gravities of the synthetic resin material 10 and the synthetic resin material 1.
It is possible to advantageously prevent non-uniform mixing of 0,
Thereby, the stable production of the cork brick 42 can be performed.

Further, in this embodiment, the cork brick 4 is used.
Since No. 2 is manufactured by injection molding, the manufacturing efficiency of the cork brick 42 can be improved.

Furthermore, in this embodiment, the surface layer formed of the synthetic resin material 10 adhered to the surface of the cork brick 42 is removed by polishing or the like to expose the cork grains 12 on the surface of the cork brick 42. Since the cork brick 42 is corroded, the texture of the cork brick 42 can be further improved.

Further, FIG. 3 shows a schematic process diagram in the second embodiment of the method for producing cork bricks according to the present invention. The cork brick manufacturing method is as follows. A molding material 14 in which a synthetic resin material 10 melted by heating and a cork particle 12 as a granular cork material are mixed is filled in a molding cavity 48 at a predetermined pressure, and then the cork particles are filled. 12
The molding material 14 is allowed to expand by a predetermined amount due to the spring back, and the molding material 14 is cooled and solidified. In the following description, for members and parts having the same structure as in the first embodiment, the same reference numerals as those in the first embodiment are used in the drawings,
Detailed description thereof will be omitted.

More specifically, first, as shown in FIG. 3A, the movable mold 46 is aligned with the fixed mold 44, and a predetermined space is provided between the two molds 44, 46. By applying the mold clamping pressure of the mold cavity 48 of the target cork brick 60 between the mold mating surfaces of the two molds 44, 46.
A primary mold clamping step for forming is performed.

The fixed mold 44 has a structure in which a fixed mold body 50 is provided with a cavity forming projection 52 for forming a molding cavity 48. On the other hand, the movable mold 46 has a structure in which a cavity forming recess 56 for forming the molding cavity 48 is provided in the movable mold body 54. Further, the cavity forming concave portion 56 has a sectional shape slightly larger than the cavity forming convex portion 52 of the fixed mold 44, and the fixed mold 44 and the movable mold 4 are provided.
The cavity forming projections 52 are fitted into the cavity forming recesses 56 with an anchor structure when the molds 6 are matched. As a result, the cavity forming concave portion 56 is covered by the cavity forming convex portion 52 between the mold matching surfaces of the fixed mold 44 and the movable mold 46, and the molding cavity 48 at the time of injection filling of the molding material 14 is formed. It is supposed to be done.

Then, under such a mold clamping pressure, as shown in FIG. 3B, the nozzle portion 38 of the heating cylinder of the injection device in which the fixed mold 44 is nozzle-touched.
Then, the molding material 14 which has been heated and melted in advance is injected at a predetermined injection pressure, and the molding material 14 is fixed to the fixed mold 44.
Then, an injection process of introducing the resin into the molding cavity 48 through the resin passage 58 and filling the same is performed. Here, the molding material 14 of the present embodiment is not the one obtained by mixing and heating the cork particles 12 and the synthetic resin material 10 and pelletizing them in advance, as in the first embodiment. The particles 12 and the synthetic resin material 10 are directly introduced into the heating cylinder from the hopper of the injection device and heated and melted by the heating cylinder. Further, as the injection device, an in-line screw type device is adopted as in the first embodiment. Further, the injection pressure of the molding material 14 is the same as that in the first embodiment, and the weight ratio of the synthetic resin material 10 and the cork particles 12 is also the same as that in the first embodiment. Furthermore, the temperatures of both molds 44 and 46 are the same as in the first embodiment.

After filling the molding cavity 48 with the molding material 14 as described above, as shown in FIG.
A secondary mold clamping step of increasing the volume of the molding cavity 48 is performed by moving the entire movable mold 46 in the direction in which it is separated from the fixed mold 44. Thereby, the molding cavity 48
It is possible to reduce the pressure exerted on the molding material 14 filled in the molding material 14, and a predetermined amount of expansion of the molding material 14 based on the springback of the cork particles 12 that has been compressed and deformed by the injection pressure is allowed. It will be. As is apparent from this, in the present embodiment, the outer shape of the cork brick 60 corresponds to the shape of the molding cavity 48 whose volume is increased.

Here, as a mechanism for controlling the volume increase of the molding cavity 48 in the present embodiment, for example, the opening / closing amount of both molds 44, 46 is moved in the direction of separating the movable mold 46 from the fixed mold 44. A mechanism that controls the distance and a mechanism that controls the opening / closing amount of both molds 44 and 46 by the mold clamping force of the main ram or the like exerted between both molds 44 and 46,
Either can be adopted.

Then, in a mold clamping state where the volume of the molding cavity 48 is increased, the molding material 14 filled in the molding cavity 48 is cooled and solidified, and then the mold is opened to release the molded product, By taking it out, a cork brick 60 having a desired shape as shown in FIG. 4 can be obtained. Further, by performing a surface layer removing step of removing the synthetic resin material 10 adhered to the surface of the cork brick 60 by polishing or the like, the cork grains 12 are exposed on the surface of the cork brick 60, and It is also possible to further improve the texture of the cork.

Therefore, the cork brick 60 thus obtained is cooled and solidified under the condition that a predetermined amount of expansion of the molding material 14 based on the springback of the cork grains 12 is allowed. The same effect as that of the one embodiment can be obtained.

Although some embodiments of the present invention have been described in detail above, these are merely examples, and the present invention is construed in a limited manner by the specific description of the embodiments. Not something.

For example, in the first and second embodiments, the cork product is manufactured by injection molding, but the cork product may be manufactured by compression molding.
Specifically, a molding material obtained by mixing a heat-melted synthetic resin material with a granular cork material is filled in a molding cavity formed between the mating surfaces of a pair of molding dies which are to be mated with each other. After applying a predetermined pressure, at least one of the pair of molding dies or a part thereof is moved in the separating direction to increase the volume of the molding cavity. As a result, a predetermined amount of expansion of the molding material based on the springback of the granular cork material is allowed, and a texture comparable to that of natural cork is provided as in the first and second embodiments. Cork products can be manufactured.

Further, in the first embodiment, the in-line screw type injection device is adopted, but as in the first embodiment, the cork particles 12 and the synthetic resin material 10 are mixed and heated to be pelletized. In the case of melting and heating the above-mentioned material again to form a molding material, it is possible to employ a plunger type injection device.

Further, in the first and second embodiments, the synthetic resin material layer formed so as to cover the surface of the molded product obtained by injection molding is removed by polishing or the like. Removal work is not always necessary.

Further, in the first and second embodiments,
The case where the method of the present invention is applied to a cork product whose surface is directly exposed to the outside has been described.
It goes without saying that the method of the present invention can be applied to cork products whose surfaces are not directly exposed to the outside, such as ball cores of baseballs.

In addition, in the first and second embodiments, the case where the method of the present invention is applied to the production of cork bricks has been described. Any of them can be advantageously applied to the production of gardening articles such as and nursery boxes, parts for welfare equipment such as handrails and wheelchairs, and the like.

Although not listed one by one, the present invention
The present invention can be carried out in a mode in which various changes, modifications, improvements, etc. are added based on the knowledge of those skilled in the art, and such a mode does not depart from the gist of the present invention.
Both are included within the scope of the present invention,
Needless to say.

[0056]

As is apparent from the above description, according to the method for producing a cork product of the present invention, the cork product can be produced in a state where the compression deformation of the granular cork material is reduced or prevented. Therefore, the texture of cork in a cork product can be improved.

[Brief description of drawings]

FIG. 1 is a schematic process diagram of a method for manufacturing a cork product in a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a cork product manufactured according to the method for manufacturing a cork product in the first embodiment.

FIG. 3 is a schematic process diagram of a method for manufacturing a cork product in the second embodiment of the present invention.

FIG. 4 is a cross-sectional view of a cork product manufactured according to the method for manufacturing a cork product in the second embodiment.

[Explanation of symbols]

10 Synthetic resin material 12 cork grains 14 Molding material 16 molding cavity

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4F202 AB19 AB26 AC01 CA11 CB01                       CK19                 4F206 AB19 AB26 AC01 JA04 JA07                       JF02 JL02 JM01 JM04 JM05                       JN03 JN11 JN21 JQ81

Claims (9)

[Claims] 1. A molding material prepared by mixing a heat-melted synthetic resin material with a granular cork material is filled in a molding cavity at a predetermined pressure, and then a predetermined amount of the molding material based on the spring back of the cork material is filled. A method for producing a cork product, characterized by allowing expansion to allow the molding material to cool and solidify. 2. A primary mold for forming a molding cavity between the mating surfaces of the fixed mold and the movable mold, with the fixed mold and the movable mold, which are opposed to each other so as to be able to move toward and away from each other, in a mold clamping state. A clamping step, and an injection step of injecting and filling the molding material obtained by heating and melting the synthetic resin material and mixing the granular cork material into the molding cavity formed in the primary mold clamping step, After filling the molding cavity with the molding material in the injection step, the volume of the molding cavity is increased by retracting the whole or a part of at least one of the fixed mold and the movable mold in a separating direction. The method for producing a cork product according to claim 1, further comprising a next mold clamping step. 3. A pelletized mixed material is formed in advance by kneading and cooling and solidifying the heat-melted synthetic resin material and the granular cork material, and heat-melting the mixed material in the injection step, The method for manufacturing a cork product according to claim 2, wherein the molding cavity is injection-filled with the molding material. 4. The method for producing a cork product according to claim 2, wherein in the injection step, the molding material is injected and filled in the molding cavity by using an in-line screw type injection device having a heating cylinder. 5. The method for producing a cork product according to claim 2, wherein the injection pressure of the molding material in the injection step is 18 to 160 MPa. 6. In the molding material, the mixing ratio of the synthetic resin material: A and the cork material: B is B / A in a weight ratio.
= 0.4-4, The manufacturing method of the cork product in any one of Claims 1 thru | or 5. 7. The method for producing a cork product according to claim 1, wherein after the molding material is filled in the molding cavity, the volume of the molding cavity is increased by 5 to 30%. 8. A surface layer removing step of removing at least a part of the surface layer of the molded article taken out from the molding cavity by polishing or the like after cooling and solidifying the molding material in the molding cavity. The method for producing a cork product according to claim 1, which is performed. 9. The method according to any one of claims 1 to 8, which is used in a state where a surface formed by the molding material made of a mixture of the synthetic resin material and the cork material is directly exposed to the outside. A cork product characterized by being used.