JPH11348074A - Grain-toned injection-molded article, and method and apparatus for manufacturing grain-toned injection-molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molded article having a straight grain pattern approximate very much to a natural one. SOLUTION: Molten resin wherein a first material 24 and a second material 25 different in colors from the first material 24 are contained in an incompletely kneaded state is prepared and the molten resin is supplied in a plurality of branch flows 26 into a cavity. Based on the actions of the branch flows 26 in a plurality, solidified parts of the second material are formed at practically prescribed intervals with respect to the individual branch flows, as a straight grain pattern, in a stage of a molded article (product part).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a woodgrain injection molded product, a method for producing a woodgrain injection molded product, and an apparatus for manufacturing a woodgrain injection molded product.

[0002]

2. Description of the Related Art As a method of manufacturing a molded article made of synthetic resin, there is a method of forming a grain pattern on the surface of the molded article as disclosed in Japanese Patent Application Laid-Open No. 8-276644. According to this one
With the synthetic resin, it is possible to mass-produce a molded article having a woody feeling close to that of natural wood.

[0003]

However, the grain pattern of the molded article obtained by the above molding method is a plate grain pattern,
It is not possible to obtain a molded article having a straight-grained pattern showing a sense of quality.

The present invention has been made in view of the above circumstances, and a first technical problem thereof is to provide a woodgrain-like injection-molded article that can have a very natural straight-grain pattern. A second technical problem is to provide a method for producing a woodgrain-like injection molded product, which can produce a molded product having a straight-grain pattern that is very natural. A third technical problem is to provide an apparatus for manufacturing a woodgrain-like injection-molded article capable of manufacturing a molded article having a straight-grain pattern that is very natural.

[0005]

In order to achieve the first technical object, the present invention (the invention of claim 1) provides:
A molten resin containing a first material and a second material having a color different from the first material in an incompletely mixed state is supplied into the cavity under a plurality of branch flows, and then solidified to form at least a surface. A plurality of shunt traces are formed in the wood-grained injection molded article, wherein the shunt traces extend in the width direction inner sides of the shunt traces in the extending direction of the shunt traces. It has a first material solidification portion where one material solidifies, and a second material solidification portion which solidifies so as to extend in the extending direction of each first material solidification portion on both sides in the width direction of each branch mark. There is a configuration.

[0006] A preferred embodiment of the first aspect is as described in the second to seventh aspects.

In order to achieve the second technical object, according to the present invention (the invention of claim 8), the first material and the first material are used.
A molten resin composed of a second material having a different color from the material is sent to the cavity resin supply end so that the second material is in an incompletely mixed state with respect to the first material. A method for manufacturing a woodgrain-like injection molded product, characterized in that molten resin is supplied into the cavity from the cavity resin supply end with a plurality of divided flows.

[0008] Preferred embodiments of the eighth aspect are as described in the ninth to eighteenth aspects.

In order to achieve the third technical object, according to the present invention (an invention of claim 19), a gate is provided at a cavity resin supply end, and the gate divides the molten resin into plural parts. The plurality of divided flows are set so as to flow toward the inside of the cavity in parallel with each other.

[0010] A preferred embodiment of the present invention is as described in claims 20 to 28.

[0011]

According to the first aspect of the present invention, the molten resin containing the first material and the second material having a color different from the first material in an incompletely mixed state is divided into a plurality of diverted portions in the cavity. , The second material enters the cavity in a parabolic manner using the flow characteristics of the plurality of shunts, after which the second material is applied to each shunt tip. Flows to the cavity resin arrival end and spreads in the width direction in conjunction with the movement to spread to the cavity resin arrival end, and spreads in the width direction. The first material, which is regulated based on functioning as a wall of the first material and solidifies after the solidification so that the first material is solidified so as to extend in the widthwise inner side in the direction of extension of the respective branch marks. A solidification part, Will be the second material solidified portion to coagulate so as to extend in the extending direction of each of the first material solidified portion in the width direction on both sides of the shunt traces are formed by dividing,
A pattern line having a substantially constant width is surely and clearly formed for each diverging trace. For this reason, the woodgrain-like injection-molded article can form a straight-grain pattern that is very natural. In addition, the second material for each of the divided streams has a spread in the width direction, from the beginning of the supply of each divided stream into the cavity,
Due to the regulation of adjacent shunts, a pattern line with a substantially constant width is reliably formed, and a straight-grain pattern that is extremely natural is formed no matter how long the total length is, even if the total length is relatively short Will be able to do that. Further, in the woodgrain-like injection molded product, since the pattern is formed in accordance with the number of shunts (two pattern lines are formed for one shunt), the pattern line is adjusted by adjusting the number of shunts. The number can be freely increased or decreased, and various straight grain patterns can be formed as desired. Furthermore, since a straight-grain pattern is formed based on the diversion trace, various shapes (for example, elbow shape,
A straight-grain pattern can also be formed on a molded product having a cap shape or the like simply by setting a branch flow at the time of molding.
For this reason, a molded product equivalent to an expensive woodworking product can be provided at low cost. In addition, since a straight-grain pattern is formed on the basis of the diversion trace, a pattern line having a substantially constant width is formed by the second material not only on the surface but also on the inside in the thickness direction based on the effect of diversion at the time of molding. That is, in the wood-grained injection-molded product, even if worn, the straight-grain pattern can be prevented from disappearing. For this reason, in the wood-grained injection-molded article, not only can the reliability of maintaining a straight-grained pattern be improved, but also, as with a natural wood, it can sufficiently cope with familiarity based on wear while showing a straight-grained pattern. become.

According to the second aspect of the present invention, since the wall thickness is set so as to be thicker at a portion where the distance of the shunt trace is longer in the extending direction of the shunt trace, the woodgrain-like injection-molded article is provided. In the manufacturing stage, the thicker the wall, the smaller the flow resistance of the branch flow can be, and any branch flow can reach the cavity resin arrival end at the same timing as much as possible, and the direction of the branch flow , And the directionality of the shunt can be suppressed from being disturbed against a force based on another shunt. For this reason, even in the case where there is a bent portion (in the case where the flow length of the branch flow is different), the branch flow which reaches the cavity resin arrival end early still does not reach the cavity resin arrival end at the time of manufacturing because the arrival timing to the cavity resin arrival end is greatly different. Suppress the flow in the flow region where there is no diversion, disturbing the orderly relationship of diversion, and after solidification, have a pattern line with a substantially constant width (very natural natural straight-grain pattern) over the entire length of each diversion trace Will be able to

According to the third aspect of the present invention, since the concave groove or the convex ridge is formed on the inner surface along the diverging trace, the concave groove or the convex ridge is formed by the woodgrain-like injection molded article. In the stage of manufacturing, the cavity will function as a guide means by changing the thickness space, based on the guide function, even if the cavity has a bent portion and the flow distance of each branch is different, Each shunt flows appropriately and directionally, and turbulence is suppressed. In addition, since the directionality of each branch is reinforced, even if a force that disturbs the direction of each branch works, it can withstand the force, and each branch is arranged in an orderly manner You will maintain the relationship. For this reason, the characteristics of each branch can be reliably used, and even when the woodgrained injection-molded article has a bent portion (when the flow distance of each branch is different), it is substantially possible for each branch. It is possible to surely have a pattern line of a fixed width (it is possible to surely form a natural grain pattern).

According to the fourth aspect of the present invention, since the first material or the second material contains wood flour, not only natural wood can be recognized visually, but also a tactile sensation similar to that of wood material. The specific heat can be ensured, and the wood texture of the wood-grained injection molded product can be further enhanced.

According to the fifth aspect of the present invention, the flat plate is
Since the plurality of shunt traces are formed so as to extend in the direction in which the flat plate extends, even if the molded article is a flat plate, a straight-grain pattern based on the plurality of shunt traces can be formed on the surface and inside thereof, and cut. Even if the processing is performed, it is possible to prevent the straight grain pattern from disappearing.

According to the sixth aspect of the present invention, a bottomed cylinder having a top wall portion and a peripheral wall portion rising from the peripheral edge of the top wall portion is provided, and a plurality of diversion traces are formed in the bottomed cylinder body. Is formed so as to extend from the peripheral wall portion on one side in the radial direction to the peripheral wall portion on the other side in the radial direction of the bottomed cylindrical body facing the peripheral wall portion on the one side in the radial direction of the bottomed cylindrical body. Even if the molded article is a bottomed cylindrical body, it extends from the radial wall part on one side in the radial direction of the bottomed cylindrical body to the peripheral wall part on the other radial side of the bottomed cylindrical body via the top wall, A straight-grain pattern based on a plurality of diversion tracks can be formed, and the appearance of the top wall portion can be improved by making the surface look like a cut section of a natural tree having a straight-grain.

According to the seventh aspect of the present invention, the bent portion is substantially L
Since it is a cylindrical body formed in the shape of a letter, since a plurality of diversion traces are formed to extend along the axis of the cylindrical body,
Even if the molded article is a cylindrical body formed in a substantially L-shape,
On its surface, a straight-grain pattern based on a plurality of diversion tracks can be formed along the axis of the cylindrical body, and a molded product similar to that obtained by performing a very troublesome bending process on natural wood can be formed.

According to the present invention, the molten resin composed of the first material and the second material having a different color from the first material is used, and the second material is incomplete with respect to the first material. Since the mixed resin is fed to the cavity resin supply end so as to be in a mixed state, the second material of the molten resin is sequentially sent out based on the flow of the molten resin and is extended along the cavity resin supply end. It will show a simple flow shape. Then, after that, the molten resin is supplied into the cavity from the cavity resin supply end with a plurality of divided flows, so that the second material is formed in a portion where each divided flow is formed.
Receiving a flow force (injection pressure) in a direction orthogonal to the cavity resin supply end, the flow branches into the cavity in a parabolic manner for each branch, and thereafter, the second material (tip) in each branch flows into each branch tip. The part flows to the cavity resin arrival end and spreads in the width direction in conjunction with the movement to flow to the cavity resin arrival end and spreads in the width direction. Is regulated on the basis of adjacent shunts, and it is extended in the flow direction of each shunt. In particular, in each branch, since the velocity gradient on both sides in the width direction is larger than the velocity gradient on the inner side in the width direction, the second material (pattern line) on both sides in the width direction of each branch is flow of the respective branch. The pattern line is stretched based on the directional shear force, and the pattern line becomes gradually thinner as the branch flow flows. For this reason, a pattern line having a substantially constant width can be formed for each branch, and a woodgrain-like injection-molded product having a clear, very natural, straight grain pattern can be manufactured.

In addition, the second material for each of the divided streams has a spread in the width direction that is different from the initial supply of each divided stream into the cavity.
Due to the regulation of adjacent shunts, a pattern line with a substantially constant width is reliably formed, and a straight-grain pattern that is extremely natural is formed no matter how long the total length is, even if the total length is relatively short Will be able to do that. Further, since the pattern is formed in accordance with the number of shunts (two pattern lines are formed for one shunt), the number of pattern lines can be freely increased or decreased by adjusting the number of shunts. A straight grain pattern can be formed as desired. Furthermore, since the straight-grain pattern is formed based on the branch flow, the straight-grain pattern can be formed on the entire shape of the molded product of various shapes (for example, elbow shape, cap shape, etc.) only by setting the branch flow at the time of molding. Around).

In addition, since the straight grain pattern is formed by the regular method based on the branch flow, the quality of the molded article (the straight grain pattern forming state) can be made uniform, and the yield can be improved. In addition, the molten resin is sent to the cavity resin supply end by causing the second material to be in an incompletely mixed state with respect to the first material. Since the flow shape is such that it extends along the cavity resin supply end just before the cavity resin supply end, any molding machine may be used as long as it has a function of sending the molten resin to the cavity side. (Regardless of the type of screw-type injection molding machine, plunger-type molding machine, one-head type injection molding machine, multi-head type injection molding machine, etc.), the equipment cost can be reduced by using a general-purpose molding machine. Become.

According to the ninth aspect of the present invention, since the supply timings of the respective divided streams supplied into the cavity are substantially the same, the respective divided streams are supplied immediately after the formation of the divided stream (immediately after the supply of the molten resin into the cavity). It is possible to utilize the properties of the adjacent branch flow (a property as a kind of regulating wall), and to measure the spread of the second material in the width direction due to the flow of the second material to the cavity resin reaching end, immediately after each branch formation. Therefore, a pattern line having a substantially constant width can be reliably formed for each branch flow. For this reason, even a molded product having a relatively short overall length can surely form a nearly natural grain pattern.

According to the tenth aspect of the present invention, since the plurality of shunts are formed by the plurality of gates arranged in parallel along the cavity resin supply end, the plurality of shunts can be concretely and reliably provided with a simple configuration. Can be formed.

According to the eleventh aspect of the present invention, when supplying the molten resin into the cavity, together with the plurality of gates,
Since the film gates arranged adjacent to the plurality of gates are used in combination, the respective branch flows having different momentums from the plurality of gates are regulated to some extent by the molten resin supplied from the film gates to the entire cavity resin supply end. (Shear resistance), the flow of each branch can be made as balanced as possible from the cavity resin supply end to the end. For this reason, the fixed width of the pattern line for each branch can be substantially maintained over the entire length, and the reliability of forming a nearly natural straight-grain pattern with no change in the pattern line width can be increased.

According to the twelfth aspect of the present invention, among the plurality of gates, the gate diameter is smaller as the timing of supplying the divided flow into the cavity is earlier, so that the supply timing of each divided flow is corrected based on the gate resistance. Thus, each branch can be supplied into the cavity at the same supply timing. For this reason, it is possible to reliably form a pattern line having a substantially constant width for each branch, regardless of the total length of the branch, using the characteristics of each branch reliably. Can be formed).

According to the thirteenth aspect of the present invention, an opening / closing valve is provided at the cavity resin supply end, and after the molten resin has spread to the entire front of the cavity resin supply end, the opening / closing valve is opened, and each of the flow branches is opened. Is supplied into the cavity, each of the divided flows can be reliably supplied into the cavity at the same supply timing. Therefore, also in this case, a pattern line having a substantially constant width can be surely formed for each branch, regardless of the total length, by reliably utilizing the characteristics of each branch. A natural grain pattern can be formed.)

According to the fourteenth aspect of the present invention, each branch is guided by the guide means at a portion inside the molded product corresponding to the inside of the molded product. Are different,
Each branch flows appropriately and directionally according to the guide means, and is prevented from being disturbed. In addition, since the directionality of each branch is reinforced, even if a force that disturbs the direction of each branch works, it can withstand the force, and each branch is arranged in an orderly manner You will maintain the relationship. Therefore, cavity (molded product)
Even if the flow distance of each branch is different due to the presence of a bent portion, a pattern line having a substantially constant width is reliably formed for each branch based on the action of each branch, and a straight grain that is almost natural A pattern can be formed.

According to the fifteenth aspect of the present invention, the flow resistance of each of the divided flows in the cavity is set such that a portion having a relatively longer flow distance flows in each of the divided flows as compared with a portion in which another divided flow flows. Therefore, at a portion where a branch flow having a relatively long flow distance flows, the branch flow becomes easier to flow, and any of the branch flows can reach the cavity resin arrival end at the same timing as possible. . In addition, in a portion where a shunt having a relatively long flow distance flows, the direction of the shunt is reinforced based on the fact that the shunt easily flows, and the shunt is opposed to the force based on the other shunt. Can be suppressed from being disturbed. For this reason, even if the cavity (molded product) has a bent portion and the flow distance of each branch is different, the branch reaching the cavity resin arrival end earlier is still insufficient because the arrival timing to the cavity resin arrival end is greatly different. It is possible to suppress the flow of the diverted flow that has not reached the flow area from disturbing the orderly relationship of the diverted flow, and to form a pattern line having a substantially constant width (an extremely natural straight-grain pattern) over the entire length for each diverted flow. This will increase the certainty.

According to the sixteenth aspect of the present invention, since the means for reducing the flow resistance of the divided flow is to make the thickness space of the cavity relatively thick in the flow region of the divided flow, the flow resistance of the divided flow is reduced. Can be specifically reduced.

According to the seventeenth aspect of the present invention, the adjustment of the thickness space of the cavity is performed by the guide groove as the guide means provided for guiding each branch at a portion corresponding to the inside of the molded product in the cavity. Even if the molded product has a bent portion and the flow distance of each branch is different, the flow resistance of each branch can be adjusted by the guide groove so that the arrival timing of each branch to the cavity resin arrival end can be made as close as possible. Not only that, the guide groove can appropriately guide the branch flow without spreading too much in the width direction, and can resist a force that disturbs (bends) the flow direction of the branch flow. Therefore, even if the cavity (molded product) has a bent portion and the flow distance of each branch is different, it flows in a desired flow path with a substantially constant width while maintaining an orderly relationship between the branches. Therefore, it is possible to increase the reliability of forming a very natural straight grain pattern.

According to the eighteenth aspect, the guiding means is
A portion having a longer flow distance of a branch flow is extended longer than a portion having a shorter flow distance. Therefore, in the case where the flow distance of each branch flow is different due to a bent portion in a cavity (molded product), the above-described claim 14 or 17 is applied. The function and effect can be exhibited more accurately.

According to the nineteenth aspect of the present invention, a gate faces the cavity resin supply end, and the gate divides the molten resin into a plurality of divided flows and flows the plurality of divided flows into the cavity in a parallel state. Is set to
With the production equipment, utilizing the characteristics of multiple branch flows,
The wood-grained injection molded product according to claim 1 can be manufactured.

According to the twentieth aspect of the present invention, since the gate is constituted by arranging a plurality of gates in a state of being juxtaposed, a plurality of shunts are specifically generated by the manufacturing apparatus. Thus, the wood grain injection molded product according to claim 1 can be specifically manufactured.

According to the twenty-first aspect of the present invention, since the gate is configured to provide a plurality of partitions by providing a plurality of partitions on the fan gate, a plurality of branches are formed by the manufacturing apparatus. Specifically, the wood-grained injection molded product according to claim 1 can be specifically manufactured.

According to the twenty-second aspect of the present invention, since the film gate faces the cavity resin supply end so as to be adjacent to the gate,
The same operation as the method according to the above-described claim 11 works, and it is possible to produce a woodgrain-like injection-molded article having a nearly straight grain pattern in which the width of the pattern line does not change so much, no matter what the total length is. become.

According to the twenty-third aspect of the present invention, since the plurality of gates are constituted by overlapping gates, in the manufacturing apparatus, the molten resin entering the overlapping gates flows in the inside thereof (flow direction). Because of this, the overlapping gates try to create as balanced a shunt as possible, and based on each shunt, a certain width of the pattern line for each shunt over the entire length. It can be almost maintained. Therefore, also in this case, it is possible to manufacture a woodgrain-like injection molded product having a nearly straight grain pattern in which the width of the pattern line does not change much.

According to the twenty-fourth aspect, since the bent portion is provided in the molten resin passage leading to the gate, in the manufacturing apparatus, before reaching the gate, the bent portion is formed by the bent portion. It is possible to stabilize the turbulence of the flow, the injection pressure and the like, and to stabilize each branch formed by the gate.

According to the twenty-fifth aspect of the present invention, the opening / closing valve is provided at the cavity resin supply end, and the opening / closing valve is set so that, when the valve is opened, a plurality of divided flows can be simultaneously flowed into the cavity from the cavity resin supply end. Therefore, in the manufacturing apparatus, the same operation as the method according to the above-described claim 13 can be performed, and the supply timing of each branch is the same regardless of the total length,
It is possible to manufacture a woodgrain-like injection-molded product having a nearly natural straight-grain pattern in which the width of the pattern line does not change much.

According to the twenty-sixth aspect of the present invention, the flow resistance at the gate is relatively increased at a portion where the timing of supply of the branch flow into the cavity is earlier. Correct the supply timing of each branch based on the same, based on the woodgrain-like injection molded product having a nearly straight grain pattern with almost no change in the width of the pattern line, regardless of the total length. It can be manufactured.

According to the twenty-seventh aspect of the present invention, since the guide means for guiding each branch flow is provided at a portion corresponding to the inside of the woodgrained injection-molded article in the cavity, the above-mentioned fourteenth aspect of the present invention relates to the manufacturing apparatus. Based on the function of the guide means, the same effect as the method according to the above-mentioned method is applied, and no matter how long the total length is, a woodgrain-like injection-molded article having a nearly straight-grained pattern in which the width of the pattern line does not change so much Can be manufactured.

According to the twenty-eighth aspect of the present invention, the thickness space in the cavity is made thicker at each part of the branch stream where the flow distance is relatively longer than at other branch areas. By operating the same operation as in the method according to No. 16 and irrespective of the total length, in the manufacturing apparatus, a woodgrain-like injection-molded article having a straight-grained pattern with almost no change in the width of the pattern line can be obtained. It can be manufactured.

[0041]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 8 show a first embodiment. In the first embodiment, reference numeral 1 in FIGS.
Is an injection-molded product according to the present embodiment immediately after molding, and a molded product 1 immediately after molding has a state in which a molten resin is solidified and is attached to a long flat product part 2 and the product part 2. The gate 3, the runner 4, and the sprue 5 are removed after the molding. This long flat product part 2 is used as a panel or the like.
Used for various applications.

As shown in FIG. 1, a plurality of branch marks 6 based on a plurality of branch flows of the molten resin are formed in the elongated flat product portion (molded product) 2.

As the above-mentioned molten resin, the second material is contained in the first material.
Materials containing materials are used. The first material and the second material have different colors, and a state before the second material is completely mixed with the first material, that is, an incompletely mixed state is used in the molding stage. It is supposed to be. Specifically, as the first material, ABS (acrylonitrile-butadiene-styrene) resin, TPE
Various resins such as (thermoplastic elastomer) resin (olefin type, nylon type, urethane type, etc.) are used alone or in combination, and as a second material, PP (polypropylene)
Resin, PBT (polybutylene terephthalate) resin, P
Various resins such as ET (polyethylene terephthalate) resin are to be used alone or in combination. Further, the first material and the second material contain a colorant, a pigment, wood flour, etc. in addition to various resins, and the content is appropriately determined according to the type of the target grain pattern. It has become. The weight ratio of the second material to the first material is preferably about the second material / the first material = 5/100. When wood flour is added, the wood flour is added in a ratio of the first material and the first material. It is preferable to add the second material in an amount of 5 to 50% (more preferably, about 10% from the viewpoint of a feeling of wood, moldability, and the like).

The plurality of diverging traces 6 are sequentially formed in the width direction of the product part 2 (up and down direction in FIG. 1) with a substantially constant width. It extends in the direction (left-right direction in FIG. 1). Each of the diversion tracks 6 has a first material solidification part 7 and a second material solidification part 8, and the first material solidification part 7 and the second material solidification part 8 are formed on the surface of the product part 2. It is formed not only inside but also inside.

The first material solidification portion 7 is solidified on the inner side in the width direction (vertical direction in FIG. 1) of each branch mark 6 so as to extend in the direction in which the branch mark 6 extends. The first material solidification part 7 occupies substantially the entirety of each branch trace 6. The second material solidification unit 8 is solidified so as to extend in the direction in which the first material solidification unit 7 extends on both sides in the width direction of each branch mark 6, and the second material solidification unit 7 It is formed with a considerably narrower line width than the first material solidified portion 7.

Next, a manufacturing method for manufacturing the molded article 1 (product part 2) and a manufacturing apparatus for implementing the manufacturing method will be described. First, before describing the manufacturing method, a manufacturing apparatus for performing the manufacturing method will be described, and the manufacturing method will be described together with the operation of the manufacturing apparatus.

As shown in FIG. 3, the manufacturing apparatus 9 for manufacturing the molded article 1 includes a molding machine 10 and a mold 11.

In the present embodiment, a general-purpose screw-type injection molding machine is used as the molding machine 10. The molding machine 10 melts the solid pellets 12 for the first material and the solid pellets 13 for the second material, which are sequentially supplied to the inside, in a cylinder 14 and melts the molten resin 15 (in FIG. Has a function of sending out the molten resin 15 to the mold 11 side at a constant pressure (injection pressure). When the molten resin 15 is generated, the molten resin 15 is generated based on temperature adjustment in the cylinder 14 or the like. The first material is set to be in an incompletely mixed state with the second material.

The mold 11 has an upper mold 16 and a lower mold 17 as shown in FIGS. 3 and 4, and the lower molds 16 and 17 are further moved by a mold clamping mechanism (not shown). When the mold is clamped, a cavity 18, a sprue 19, a runner 20, and a gate 21 are to be formed therein, as shown in FIGS. Cavity 1
8, a space corresponding to the long flat plate-shaped product part 2 is formed, and the cavity 18 holds a space having a constant width and a constant thickness, and is opposed to the cavity resin supply end 22 and the cavity resin supply end 22 facing each other. End 23 is formed. The sprue 19 is supplied from the molding machine 10 to the molten resin 15.
, And the sprue 19 is connected to the runner 20. In this case, a bent portion (bent path) that changes the flow direction of the molten resin 15 may be formed in the sprue 19. Runner 20 includes sprue 19 and gate 21
And a runner connecting the two, and in the present embodiment,
The runner 20 has a substantially semicircular cross section and faces the cavity resin supply end 22 while facing the cavity resin supply end 22.
(See FIGS. 5 and 6). In this embodiment, a plurality of overlap gates 21a are used as the gates 21. The plurality of overlap gates 21a are arranged at predetermined intervals in the extending direction of the runner 20 (the cavity resin supply end 22).
Each of the overlap gates 21a connects the runner 20 and the cavity 18 across the lower surface of the runner 20 and the lower surface near the cavity resin supply end 22.

Next, a method of manufacturing the molded article 1 (product part 2) will be described together with the operation of the manufacturing apparatus. First, in the molding machine 10, the solid pellet 1 for the first material is used.
The solid material pellets 13 for the second material and the second material are supplied into the cylinder 14 at predetermined supply speeds, and
And the second material 25 is generated, and the molten resin 15 is continuously sent to the mold 11 side. Therefore, the second material 25 of the molten resin 15 is
Riding on the flow of the molten resin 15, the molten resin 15
The flow of the plurality of linear second materials 25 is further based on the flow of molten resin as shown in FIG. Flow to 20 and runner 2
0, the runner 20 (cavity resin supply end 2)
It shows a flow shape extending in the extending direction of 2). In this case, when the sprue 19 or the like has a bent portion (bent path), pulsation of the molten resin 15 and the like are suppressed.

When the molten resin 15 is filled in the runner 20, as shown in FIG. 6, the molten resin 15 is subjected to an injection pressure, and the cavity 18 is moved from each overlap gate 21a.
Will be supplied within. Thereby, the molten resin 15
Is divided into a plurality of shunts 26 corresponding to the number of the overlap gates 21a and enters the cavity 18 on the basis of each overlap gate 21a. , And flows toward the cavity resin arrival end 23. Thereafter, as time elapses, the leading end of each branch 26 flows to the cavity resin arrival end 23 and tries to expand in the width direction, but the adjacent branches 26 regulate each other, and each branch 26 is substantially It flows in a parallel state. In conjunction with the movement of each branch 26, the second material 25 (tip) in each branch also flows to the cavity resin reaching end 23 and spreads in the width direction as shown in FIG. However, the spread of the second material 25 in the width direction is regulated based on the adjacent branch streams 26, and is extended in the flow direction of each branch stream 26, and the second material 25 having a substantially constant width is provided for each branch stream 26. (A pattern line having a substantially constant width) is formed. In particular, in each branch 26, since the velocity gradient on both sides in the width direction is greater than the velocity gradient on the inner side in the width direction, the pattern flow of the second material 25 on both sides in the width direction of each branch 26 is The pattern flow of the second material 25 is gradually narrowed with the flow of the branch flow 26. Of course, at this time, since the pattern flow of the second material 25 is formed based on the action of the plurality of branch flows 26, it occurs not only on the surface side but also inside.

In this case, since the plurality of split streams 26 are supplied into the cavity 18 at substantially the same timing, the spread of the second material 25 in each split stream 26 in the width direction is equal to that of each split stream 2.
From the beginning of the supply of 6, the adjacent branch flow 26 is regulated, and the pattern flow immediately occurs from the cavity resin supply end 22. In this case, as shown in FIG.
Using the overlap gate 21a and the runner 20
At the connection between the overlap gate 21a and the cavity 18, the flow direction of the molten resin 15 is changed, so that the momentum of the split flow 26 supplied from each overlap gate 21a, the supply timing and the like are balanced. This also contributes to the generation of the pattern flow of the second material 25 in which the width does not change much for each branch 26 immediately from the cavity resin supply end 22.

When the supply of the molten resin 15 into the cavity 18 by the plurality of divided flows 26 is completed (filled), the solidification of the molten resin 15 is awaited.
6 and 17 are opened, and the above-mentioned molded article 1 is taken out.

Therefore, in the first embodiment, a pattern flow having a substantially constant width is formed for each branch 26 regardless of the total length of the product section 2 including the relatively short overall length. It is possible to obtain a molded product 1 (product portion 2) having a sharp, natural-grained pattern that is very natural. In addition, in obtaining the product section 2, the branch 2
The number of pattern flows of the second material 25 can be freely increased or decreased by adjusting the number 6 (two pattern lines of the second material 25 are formed on both sides in the width direction of one branch stream 26), and various straight-grain patterns can be formed. It can be formed as desired. Further, the molten resin 15 is sent to the cavity resin supply end 22 in such a manner that the second material 25 is in an incompletely mixed state with the first material 24, and the second material 25 is utilized by utilizing the flow. ,
Since the flow shape extends along the cavity resin supply end 22 just before the cavity resin supply end 22, it is not necessary to form a pattern with a multi-head injection molding machine or the like, and a general-purpose injection molding machine can be used. Thus, the equipment cost can be reduced.

FIG. 8 is a photograph showing the surface of the flat product part 2. According to this photograph, a straight grain pattern can be recognized on the surface of the product part 2 from the start end (the cavity resin supply end side) to the end. In this case, the product part 2 was molded under the following molding conditions. 1) Size (length 125mm, width 50mm, thickness 1mm) 2) Gate (number: 10 types: multi-point overlapping gate with different diameters + film gate) 3) Resin (first material: ABS second material: PBT) 4) Injection Conditions (Cylinder temperature: 235 ° C Mold temperature:
60 ° C Maximum injection pressure: 1500Kg / cm2) 5) Others (clamping force: 60t Screw diameter of injection molding machine: 46mm)

9 and 10 show the second embodiment, FIG. 11 shows the third embodiment, FIG. 12 shows the fourth embodiment, FIG. 13 shows the fifth embodiment, and FIGS. 14 to 20 show the sixth embodiment. 21 to 23
Shows a seventh embodiment. In each of the embodiments, the same reference numerals are given to the same components as those in the embodiments after the first embodiment and before the embodiments, and the description thereof will be omitted.

In the second embodiment shown in FIGS. 9 and 10, the product portion 2 (molded product) has a plurality of ridges 27 formed on the inner surface as shown in FIG. The plurality of ridges 27 are arranged at predetermined intervals (every branch) in the width direction of the product part 2, and each ridge 27 extends in the direction in which the product part 2 extends.

In order to form the product portion 2 having such ridges 27, a lower die 17 having a plurality of guide grooves 28 is used as shown in FIG. The plurality of guide grooves 28 are extended in a side-by-side state, and each of the guide grooves 28 is filled with the molten resin 15 to form the ridge 27 of the product portion 2. .

Therefore, in the second embodiment, when the product part 2 is formed, each guide groove 28 functions as a guide for the molten resin 15. Flows appropriately with directionality and is prevented from being disturbed. Moreover, each branch 26
Is strengthened, even if a force that disturbs the direction of each branch works, it can withstand the force, and each branch 26 is arranged in an orderly and substantially straight arrangement. You will maintain the relationship. For this reason, the characteristic of each branch 26 can be utilized reliably, and after solidification, the product part 2 has the second material solidification part 8 (pattern line) of substantially constant width for each branch trace 6 reliably. Will be able to

In the third embodiment shown in FIG. 11, a fan gate 21b is used as the gate 21. The fan gate 21b is provided with a plurality of partitions 30 before the cavity resin supply end 22, and the plurality of branches 26 are generated by the molten resin 15 passing between the plurality of partitions 30. The plurality of split streams 26 are to enter the cavity 18.

In the fourth embodiment, a plurality of gates 2
Among 1, the gate diameter is smaller as the supply timing of the branch flow 26 into the cavity 18 is earlier.
That is, for example, as shown in FIG. 12, when the sprue 19 is located at the center in the extending direction of the runner 20 as the mold 11, the supply timing of each branch 26 to the cavity 18 is substantially the same. The diameter of the gate 21 (gate facing the outlet of the sprue 19), which is liable to receive the dynamic pressure of the molten resin, is made smaller than that of the other gates in order to further increase the accuracy of the supply timing of each branch 26. , Its passage resistance has been increased. This enhances the timing of the supply of each branch 26 to be the same, so that the operation of each branch 26 described above can be reliably used, and the second part 26 having a substantially constant width is provided on the surface of the product part 2 for each branch 6. The material solidification portion 8 (pattern line) can be represented.

In the fifth embodiment, as shown in FIG. 13, an on-off valve 31 is provided in front of the cavity resin supply end 22. By using this on-off valve 31,
After the molten resin 15 has spread to the whole of the cavity resin supply end 22, the on-off valve 31 is opened, and
Is supplied into the cavity 18 so that each branch 2
The supply timing of 6 becomes extremely high in accuracy, and the above-described operation of each branch 26 can be reliably used.

In the sixth embodiment shown in FIGS. 14 to 20, in the top wall portion 32 and the peripheral wall portion 33 rising from the peripheral edge thereof.
This shows a cylindrical cap body 34 (2) having a bottom and a straight grain pattern formed thereon. That is, in the sixth embodiment, as shown in FIG.
In addition to the product part 2, a film gate part 35, a plurality of side gates 36 arranged in parallel, and the like are provided. The film gate portion 35 and the plurality of side gate portions 36 are
4, a plurality of side gates 36 are provided on the peripheral wall 33 on one side in the radial direction at the peripheral edge of the opening.
Are arranged vertically adjacent to the film gate portion 36. Then, the plurality of side gate portions 35, the film gate portions 36, and the like are removed after the molding, and the product portion 2 is formed.
As shown in FIG. 14, a cap body 34 is used as an end cap of the handrail 41 or the like.

In order to mold such a molded article 1, as shown in FIG. 16, a recess 37 is formed in the upper mold 16, and the lower mold 17 is fitted into the recess 37 of the upper mold 16. A convex portion 38 forming the bottomed cylindrical cavity 18 is formed.
In addition, the upper and lower dies 16 and 17 are formed so that the film gate 21c and the plurality of side gates 21d face the cavity 18 corresponding to the above-described film gate portion 35 and the plurality of side gate portions 36, respectively. As shown in FIG. 16 and FIG. 17, a plurality of guide grooves 28 are formed on the tip end surface of the convex portion 38 so as to extend from one side in the radial direction to the other side in the radial direction.

When the molding is performed using such a mold 11, as shown in FIG. 18, a plurality of shunts 26 are generated by the side gate 21d, and the action of each shunt 26 described above can be produced. However, even when the molded article 1 has a passage having a different distance with respect to the distance from the cavity resin supply end 22 to the cavity resin arrival end 23 as in the molded article 1 (the radial wall portion on one side in the radial direction). Is different from the distance from the peripheral wall portion on the other side in the radial direction via the top wall portion 32 to the distance from the peripheral wall portion on the one radial side to the peripheral wall portion on the other side in the radial direction via the peripheral wall portion 33). Based on the guide function of the groove 28, each of the branch streams 26 flows appropriately with directionality and is prevented from being disturbed. In addition, the directionality of each branch 26 is reinforced,
Even if a force acting to disturb the direction of each of the shunts 26 works,
It will be able to withstand that force, and each branch 26
Will maintain an orderly arrangement. For this reason, even with the cap body 34, the second material solidified portion 8 (pattern line) having a substantially constant width can be reliably formed on the top wall portion 32 for each branch flow mark 6.

At this time, of course, the plurality of side gates 21d
And the film gate 21c are arranged vertically adjacent to each other, so that even if there is a difference in momentum between the plurality of branch streams 26 formed by the plurality of side gates 21d, the molten resin 15 , And each branch 26 is balanced.

On the other hand, the plurality of guide grooves 28 are
In the case where the second material solidification portion 8 (straight grain pattern) can be formed on the basis of the plurality of branch flows 26 as shown in FIG. The interval between the two material solidification parts 8 is determined by the cavity resin reaching end 23.
It will be narrowed as it approaches. This is because when the molten resin 15 flows from the cavity resin supply end 22 to the cavity resin arrival end 23, the molten resin passing through the peripheral wall portion corresponds to the molten resin 1 passing through the top wall portion.
5 reaches the cavity resin reaching end 23 earlier than
This is considered to apply a force from the side to the molten resin 15 passing through the portion corresponding to the top wall portion. In this regard, the plurality of guide grooves 28
Is formed on the convex portion 38 of the lower mold 17, the force sufficiently resists this force.

FIG. 20 is a photograph showing the surface of the cap body 34. According to this photograph, a straight grain pattern can be recognized on the surface of the top wall portion 32 of the cap body 34 from the start end (the cavity resin supply end side) to the end. In this case, the cap body 32 was molded under the following molding conditions. 1) Size (34 mm in diameter, 10 mm in height, 1 mm in thickness) 2) Gate (number: 8 types: multi-point overlap gate with same diameter + film gate) 3) Resin (first material: ABS second material: PBT) 4 ) Injection conditions (cylinder temperature: 235 ° C Mold temperature:
60 ° C Maximum injection pressure: 1500Kg / cm2) 5) Others (clamping force: 60t Screw diameter of injection molding machine: 46mm)

As a matter of course, the shorter the flow distance of the branch stream 26 is, instead of or together with the guide groove 28, the thickness space (cavity space thickness) of the portion corresponding to the peripheral wall portion.
And the flow resistance of the branch stream 26 is increased, and the molten resin 1
5, the arrival timing at the cavity resin arrival end 23
No matter where you go, you may make it almost the same.

In the seventh embodiment shown in FIGS. 21 to 23, the product portion 2 is provided along the entire circumference of a substantially L-shaped (elbow-shaped) bent cylinder 39 along the axis of the bent cylinder 39. It shows a straight-grained pattern formed so as to extend. That is, as shown in FIG. 22, the molded article 1 immediately after molding includes a gate section 42, a runner section 43, and the like, in addition to the bent cylindrical body 39 as the product section 2. In the bent cylinder 39, a plurality of second material solidified portions 8 are formed at predetermined intervals in a circumferential direction,
Each of the second material solidified portions 8 extends from one end to the other end thereof along the axis of the bent cylinder 39. As shown in FIG. After removal of the part 42, the runner part 43, and the like, it is to be used at the end of the handrail 41.

In order to form such a molded product 1, as shown in FIG. 23, a substantially L-shaped bent cylinder is provided inside the mold 11 by using cores 45 and 46 as mold elements. A body-forming space (cavity 18) is formed, and a plurality of overlap gates 21a face the entire periphery of one end side (cavity resin supply end 22). In this case, regarding the distance from one end to the other end of the bent cylinder 39, the outer peripheral side 3 of the bent cylinder 39
9a is longer than the inner peripheral side 39b, and based on the difference, even if a plurality of branch flows 26 are generated in the cavity 18,
Since the plurality of shunts 26 are easily disturbed, the cores 45, 4
A plurality of guide grooves 28 are formed on the outer peripheral surface of the tube 6, and the plurality of guide grooves 28 resist turbulence of the respective branch flows 26. As a result, even if the molded product is a bent cylindrical body 39 bent in a substantially L-shape, as shown in FIG. The pattern line is formed, and a straight-grain pattern can be obtained.

In this case, as another mode, the cores 45, 4
In 6, the guide groove may be formed longer at a portion (outer peripheral side) where the flow distance of the split stream 26 is longer, or the guide groove 28 may be deeper at a portion where the flow distance of the split stream 26 is longer.

As still another embodiment, instead of the guide groove,
The thickness space of the cavity 18 may be gradually thicker as the flow distance of the branch flow 26 is longer. With this, the same operation and effect as those of the seventh embodiment can be obtained.

Although the embodiments have been described above, the present invention includes the following aspects. 1) Arrange a plurality of gates 21 so that the interval between them is small.
As a result, it becomes possible to bring the grain closer to the grain of the natural tree. 2) Use overlap gate and film gate together.

It should be noted that the object of the present invention is not limited to what is specified, but also includes providing what is substantially preferable or corresponding to what has been described as an advantage.

[Brief description of the drawings]

FIG. 1 is a plan view showing a molded product immediately after molding in a first embodiment.

FIG. 2 is an enlarged side view of FIG.

FIG. 3 is an explanatory diagram illustrating a manufacturing apparatus according to the first embodiment.

FIG. 4 is a partially enlarged cross-sectional view showing a mold according to the first embodiment.

FIG. 5 is an explanatory diagram illustrating a flow of a molten resin in a mold.

FIG. 6 is an operation state diagram illustrating a continuation of FIG. 5;

FIG. 7 is an explanatory diagram illustrating generation of a pattern flow of a second material for each branch flow.

FIG. 8 is a photograph showing a product portion (molded product) surface according to the first embodiment.

FIG. 9 is a perspective view showing a product part (molded product) in a second embodiment.

FIG. 10 is a partially enlarged sectional view showing a mold for molding the molded article of FIG. 9;

FIG. 11 is an explanatory view showing a gate structure according to a third embodiment.

FIG. 12 is an explanatory diagram showing a gate structure according to a fourth embodiment.

FIG. 13 is an explanatory view showing a gate structure according to a fifth embodiment.

FIG. 14 is a perspective view showing a handrail using a molded product (cap body) according to a sixth embodiment.

FIG. 15 is a perspective view showing a molded product according to a sixth embodiment.

FIG. 16 is a partially enlarged sectional view showing a mold for molding a molded article according to a sixth embodiment.

FIG. 17 is a partially enlarged perspective view showing a lower mold according to a sixth embodiment.

FIG. 18 is an explanatory diagram illustrating a flow of a molten resin in a mold in a plan view in the sixth embodiment.

FIG. 19 is an explanatory diagram illustrating a flow of a molten resin in a mold in a plan view when a guide groove is not formed in a convex portion of a lower mold according to a sixth embodiment.

FIG. 20 is a photograph showing a product portion (cap body) surface according to the sixth embodiment.

FIG. 21 is a perspective view showing a handrail using a molded product (bent cylinder) according to the seventh embodiment.

FIG. 22 is a view showing a molded product according to a seventh embodiment.

FIG. 23 is a partially enlarged sectional view showing a mold according to a seventh embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Molded product 2 Product part 6 Separation mark 7 1st material solidification part 8 2nd material solidification part 9 Manufacturing apparatus 11 Die 15 Melt resin 16 Upper mold 17 Lower mold 18 Cavity 21 Gate 21a Overlap gate 21b Fan gate 21c Film gate 21d Side gate 22 Cavity resin supply end 23 Cavity resin arrival end 26 Branch flow 27 Convex portion 28 Guide groove 30 Partition portion 31 Open / close valve 32 Top wall portion 33 Peripheral wall portion 34 Cap body 39 Bent cylinder

Claims (28)

[Claims] 1. A molten resin containing a first material and a second material having a color different from the first material in an incompletely mixed state is supplied into the cavity under a plurality of partial flows, and then solidified. A woodgrain-like injection-molded article having at least a plurality of shunt traces formed on a surface thereof, wherein each of the shunt traces extends in a widthwise inner side of the respective shunt trace in a direction in which the respective shunt trace extends. A first material solidifying portion in which the first material solidifies, and a second material solidifying portion solidifying so as to extend in the direction in which the first material solidifying portion extends on both sides in the width direction of each branch mark. A wood-grained injection-molded article having: 2. The wood-grained injection-molded article according to claim 1, wherein the wall thickness is set to be larger in a portion where the distance of the branch mark is longer in the extending direction of the branch mark. . 3. The woodgrain-like injection-molded article according to claim 1, wherein a concave groove or a ridge is formed on the inner surface along the diverging trace. 4. The method according to claim 1, wherein the first material or the second material contains wood flour.
A wood-grained injection-molded article characterized by the following. 5. The wood-grained injection-molded product according to claim 1, wherein the molded product is a flat plate, and the plurality of diverging traces are formed to extend in a direction in which the flat plate extends. . 6. The bottomed cylindrical body according to claim 1, wherein the cylindrical body has a top wall portion and a peripheral wall portion rising from a peripheral portion of the top wall portion, and It is formed so as to extend from the radially outer peripheral wall portion of the bottomed cylindrical body toward the radially other peripheral wall portion of the bottomed cylindrical body facing the radially one peripheral wall portion of the bottomed cylindrical body. A wood-grained injection-molded product. 7. The cylindrical body according to claim 1, wherein the cylindrical body is bent to have a substantially L-shape, and the plurality of branch marks extend along an axis of the cylindrical body. A wood-grained injection molded product characterized by being formed. 8. A molten resin composed of a first material and a second material having a different color from the first material, so that the second material is in an incompletely mixed state with respect to the first material. And feeding the molten resin to the cavity from the cavity resin supply end with a plurality of divided flows, and then feeding the molten resin into the cavity from the cavity resin supply end. 9. The method for producing a woodgrain-like injection molded product according to claim 8, wherein the supply timings of the respective branch streams supplied into the cavity are substantially the same. 10. The method according to claim 8, wherein the plurality of branches are formed by a plurality of gates arranged in parallel along the cavity resin supply end. . 11. The method according to claim 10, wherein when supplying the molten resin into the cavity,
A method for producing a woodgrain-like injection-molded product, wherein a film gate arranged adjacent to the plurality of gates is used together with the plurality of gates. 12. The woodgrain-like injection according to claim 10, wherein, among the plurality of gates, a gate having a earlier supply timing of the branch flow into the cavity has a smaller gate diameter. Manufacturing method of molded article. 13. The cavity resin supply end according to claim 9, wherein an on-off valve is provided at the cavity resin supply end, and after the molten resin has spread over the entire cavity resin supply end,
A method for producing a woodgrain-like injection-molded product, comprising opening the on-off valve and supplying each branch to the cavity. 14. The method for producing a woodgrain-like injection-molded article according to claim 8, wherein each branch is guided by a guide means at a portion corresponding to the inside of the molded article in the cavity. 15. The flow resistance according to any one of claims 8 to 14, wherein a flow resistance of each of the divided flows in the cavity is set such that a portion having a relatively longer flow distance among the divided flows flows to a portion where another divided flow flows. A method for producing a woodgrain-like injection-molded article, characterized in that it is made smaller than that. 16. The woodgrain according to claim 15, wherein the means for reducing the flow resistance of the split flow is to make the thickness space of the cavity relatively thick in the flow region of the split flow. Manufacturing method for injection molded products. 17. The method according to claim 16, wherein adjustment of the thickness space of the cavity is performed by a guide groove serving as a guide means provided to guide each branch at a portion inside the molded product inside the cavity. Production method of wood grain injection molded products. 18. The method for producing a woodgrain-like injection-molded article according to claim 14, wherein the guide means is extended longer at a portion where the flow distance of the split flow is longer than at a portion where the flow distance is shorter. 19. A gate is provided at the cavity resin supply end, wherein the gate is configured to divide the molten resin into a plurality of divided flows and to flow the plurality of divided flows into the cavity in a parallel state. A woodgrain injection molded article manufacturing apparatus, characterized in that: 20. The apparatus according to claim 19, wherein the gate is configured by arranging a plurality of gates side by side. 21. The method of claim 19, wherein the gate is configured to provide a plurality of partitions on a fan gate to form the plurality of shunts. apparatus. 22. The apparatus for manufacturing a woodgrain-like injection-molded product according to claim 20, wherein a film gate is provided at the cavity resin supply end so as to be adjacent to the gate. 23. The apparatus according to claim 20, wherein the plurality of gates are constituted by overlap gates. 24. The apparatus for manufacturing a woodgrain-like injection-molded product according to claim 19, wherein a bent path portion is provided in the molten resin passage leading to the gate. 25. The cavity resin supply end according to claim 19, further comprising an on-off valve provided at the cavity resin supply end, wherein the on-off valve divides the plurality of divided flows from the cavity resin supply end into the cavity when the valve is opened. A woodgrain-like injection-molded product manufacturing apparatus, which is set so as to flow into the same time. 26. The grain according to claim 19, wherein the flow resistance in the gate is relatively increased in a portion where a timing of supplying a branch flow into the cavity is earlier. Equipment for manufacturing injection-molded products. 27. The woodgrain-like injection-molded article according to claim 19, wherein a guide means for guiding each branch is provided at a portion corresponding to the inside of the molded article in the cavity. Manufacturing equipment. 28. The flow path according to claim 19, wherein the thickness space in the cavity is thicker in a part of each of the branch streams having a relatively longer flow distance than in other branch sections. A woodgrain injection molded product manufacturing apparatus characterized by the following.