JP4347725B2 - Co-extruded body and method for producing the same - Google Patents

Description

  This invention consists of a structure in which a buried part is embedded and integrated in a part of the main body part.For example, a molded body used for building materials such as a handrail, a skirting board, a rising collar, a waistboard, a deck material, etc. The present invention relates to a method of manufacturing by extruding simultaneously without generating a gap with an embedded portion.

When walking in the dark, there is a possibility of falling over, for example, by hooking a foot on a portion protruding from the floor surface, and it is generally difficult to ensure sufficient walking safety. Therefore, in recent years, it has been proposed to improve the visibility by adding a phosphorescent agent to a member to be alerted such as a protruding portion and causing the phosphorescent agent to emit light in the dark such as at night. For example, in a wiring protective cover including a base portion attached to a floor surface and a cover portion that forms a space for storing wiring between the base portion, a phosphorescent agent is applied to a part of the surface side of the cover portion. A configuration in which a kneaded translucent resin is embedded and integrated is known (see Patent Document 1).
JP 2003-259530 A (Claim 1, paragraph 0026, FIGS. 1 and 2)

  By the way, in recent years, artificial wood made of synthetic resin to which a wood texture is imparted is increasingly used as a substitute for natural wood in a wide variety of applications. In particular, demand for building materials is growing. As such an artificial wood, an extrudate obtained by extruding a synthetic resin containing wood flour is often used. For artificial wood used for such building materials, etc., it is now required to contain a phosphorescent agent in order to call attention in the dark as in the case of the wiring protective cover described above. Yes.

  From such a background, the present inventors have a light-transmitting thermoplastic resin containing a phosphorescent agent in part of the surface of the long main body (101) made of a thermoplastic resin containing wood flour. An attempt was made to co-extrusion molding (simultaneous extrusion molding) from the viewpoint of excellent productivity, as shown in FIG. It was found that there was a problem that a gap (103) was generated between the main body portion (101) and the embedded portion (102) in the molded body. In addition, there is a problem that sink marks (depressions) (104) are generated at the center of the exposed surface of the embedded part (102).

  Of course, if the body portion (101) and the embedded portion (102) are separately extruded and then integrated, the problems of gap generation and depression generation can be solved, but productivity is remarkable. However, such a manufacturing method cannot be practically adopted.

  The present invention has been made in view of such a technical background, and a molded body in which a buried portion is embedded and integrated in a part of a main body portion is subjected to simultaneous extrusion molding using an extrusion die, thereby the main body portion. It is an object of the present invention to provide a manufacturing method in which a gap is not generated between an embedded portion and a buried portion, and an exposed surface of the buried portion is not caused.

  In order to achieve the above object, the present inventors first investigated the cause of a gap between the main body portion and the embedded portion in the molded body obtained by the coextrusion molding. As a result, the volume change with respect to the temperature change is very small, so the thermoplastic resin (main body part) containing the wood powder has a small volume change with respect to the temperature change. Since the phosphorescent-containing thermoplastic resin (embedded part) that does not contain powder has a large volume change with respect to temperature change, the embedded part shrinks more than the body part in the process of cooling the extruded molded body. The degree was large, and it was found that a gap was generated between the main body and the embedded portion.

  Therefore, the present inventors have such a case where there is a difference in volume change rate with respect to temperature change between the main body portion and the embedded portion (when the embedded portion has a larger volume change rate with respect to temperature change than the main body portion). ) However, as a result of earnest research on a method that can perform co-extrusion well without problems, the discharge amount per unit area and unit time of the resin that constitutes the embedded part is changed to the discharge amount per unit area and unit time of the resin that constitutes the main body part. Simultaneously in a state where the amount is set to 1.2 to 1.6 times the amount, and at least the exposed surface of the embedded portion extruded from the discharge surface of the extrusion mold is pressed inward by the pressing member. As a result of the extrusion molding, the inventors have found that simultaneous extrusion molding can be performed without causing a gap between the main body portion and the embedded portion and without causing sink marks in the embedded portion, thereby completing the present invention.

[1] An embedded portion made of a second thermoplastic resin having a volume change rate with respect to a temperature change larger than that of the first thermoplastic resin is embedded and integrated in a part of the main body portion made of the first thermoplastic resin. When manufacturing the formed body by coextrusion molding using an extrusion die,
The discharge amount per unit area / unit time of the second thermoplastic resin from the extrusion mold is 1.2 of the discharge amount per unit area / unit time of the first thermoplastic resin from the extrusion mold. Set to a range of ~ 1.6 times,
Simultaneously in a state where at least the exposed surface of the embedded portion of the co-extruded product extruded from the discharge surface of the extrusion mold is pressed inward by a pressing member fixed in a state of being connected to the discharge surface of the extrusion mold. A method for producing a coextruded product, characterized by performing extrusion molding.

  [2] The discharge amount per unit area / unit time of the second thermoplastic resin from the extrusion mold is the discharge amount per unit area / unit time of the first thermoplastic resin from the extrusion mold. The method for producing a coextruded article according to item 1, wherein the coextruded article is set in a range of 1.3 to 1.5 times.

[3] Translucent second resin containing a thermoplastic resin in a part of a main body portion made of a first resin containing a cellulose material such as wood powder and a thermoplastic resin, and the volume with respect to temperature change When manufacturing a molded body in which an embedded portion made of a second resin having a rate of change larger than that of the first resin is embedded and integrated by coextrusion using an extrusion die,
The discharge amount per unit area / unit time of the second resin from the extrusion mold is 1.2 to 1.6 of the discharge amount per unit area / unit time of the first resin from the extrusion mold. Set to double the range,
Simultaneously in a state where at least the exposed surface of the embedded portion of the co-extruded product extruded from the discharge surface of the extrusion mold is pressed inward by a pressing member fixed in a state of being connected to the discharge surface of the extrusion mold. A method for producing a coextruded product, characterized by performing extrusion molding.

  [4] The discharge amount per unit area / unit time of the second resin from the extrusion mold is 1.3 to the discharge amount per unit area / unit time of the first resin from the extrusion mold. 4. The method for producing a coextruded article according to item 3 above, which is set to a range of 1.5 times.

  [5] The method for producing a coextruded molded article according to item 3 or 4, wherein the second resin contains a phosphorescent agent.

  [6] The method for producing a coextruded article according to item 5 above, wherein the content of the phosphorescent agent in the second resin is 1 to 10% by mass.

  [7] The method for producing a coextruded article according to any one of items 3 to 6, wherein the content of the cellulose material in the first resin is 20 to 80% by mass.

  [8] The method for producing a coextruded article according to any one of items 3 to 7, wherein wood powder is used as the cellulose material.

  [9] Simultaneous use according to any one of items 3 to 8, wherein polyethylene is used as the thermoplastic resin constituting the first resin, and polymethyl methacrylate is used as the thermoplastic resin constituting the second resin. A method for producing an extruded product.

  [10] A coextruded article produced by the production method according to any one of items 1 to 9.

  In the invention of [1], the discharge amount of the second thermoplastic resin constituting the embedded portion is set in a range of 1.2 to 1.6 times the discharge amount of the first thermoplastic resin constituting the main body portion. In addition, since the coextruded molded body is extruded from the discharge surface of the extrusion mold and at least the exposed surface of the embedded portion is pressed inward by the pressing member, the embedded portion is temperature-changed more than the main body portion. Despite being composed of a resin having a large volume change rate, it is possible to form without causing a gap between the main body portion and the embedded portion, and to prevent the occurrence of sink marks on the exposed surface of the embedded portion. .

  In the invention of [2], the occurrence of a gap between the main body portion and the embedded portion can be reliably prevented.

  In the invention of [3], the discharge amount of the second resin constituting the embedded portion is set in a range of 1.2 to 1.6 times the discharge amount of the first resin constituting the main body portion, and extrusion is performed. Since the coextruded product is extruded from the die ejection surface with at least the exposed surface of the embedded part pressed inward by the pressing member, the volume change rate of the embedded part with respect to temperature change is higher than the body part. Despite being made of a large resin, it can be molded without creating a gap between the main body portion and the embedded portion, and the occurrence of sink marks on the exposed surface of the embedded portion can be prevented. Moreover, since a coextruded molded body having a structure in which the cellulose material is contained in the main body portion is obtained, a molded body having a wood texture can be provided.

  In the invention of [4], the occurrence of a gap between the main body portion and the embedded portion can be reliably prevented.

  In the invention of [5], a coextruded molded article having a structure in which a luminous agent is contained in a translucent buried portion can be produced. The obtained co-extruded product emits the energy stored in the phosphorescent agent as afterglow (for example, yellowish green), so that the embedded part appears to shine in the dark at night, etc. Safety can be improved and safety such as walking can be improved. In addition, since the embedded portion looks shining in the dark, a unique atmosphere can be created and the design can be improved. Therefore, the co-extruded product produced in the invention of [5] is suitably used for building materials such as handrails, skirting boards, raised ridges, waistboards, deck materials and the like.

  In the invention of [6], since the content rate of the phosphorescent agent in the second resin is 1 to 10% by mass, the afterglow is sufficient to be visible in the dark.

  In the invention of [7], since the content of the cellulose material in the first resin is 20 to 80% by mass, it is possible to produce a molded body that has sufficient strength and has a sufficient wood texture. .

  In the invention of [8], since wood powder is used as the cellulose material, a wood texture closer to that of natural wood can be imparted.

  In the invention of [9], since polymethyl methacrylate is used as the thermoplastic resin constituting the buried portion, the transparency of the buried portion can be improved, and thereby the afterglow by the phosphorescent agent in the buried portion. Can be sufficiently released to the outside, and the visibility can be further improved. Moreover, since polyethylene is used as the thermoplastic resin constituting the main body, the extrusion moldability is good.

  In the invention of [10], as a molded body in which the embedded portion is embedded and integrated in a part of the main body portion, there is provided a good state in which there is no gap between the main body portion and the embedded portion.

  In the method for producing a coextruded molded body according to the present invention, a second thermoplastic resin having a volume change rate with respect to a temperature change larger than that of the first thermoplastic resin is formed in a part of the main body portion made of the first thermoplastic resin. When a molded body in which the embedded portion made of resin is embedded and integrated is manufactured by simultaneous extrusion molding using an extrusion die, the second thermoplastic resin is discharged from the extrusion die per unit area / unit time. The amount (volume) is set in the range of 1.2 to 1.6 times the discharge amount (volume) per unit area / unit time of the first thermoplastic resin from the extrusion mold, and the extrusion mold Co-extrusion molding is carried out in a state where at least the exposed surface of the embedded portion of the coextruded molded body extruded from the ejection surface of the extrusion mold is pressed inward by a pressing member fixed in a state of being connected to the ejection surface of the mold. It is characterized by that.

  According to this manufacturing method, the discharge amount per unit area / unit time of the second thermoplastic resin constituting the embedded portion is set to the discharge amount per unit area / unit time of the first thermoplastic resin constituting the main body portion. Simultaneously in a state where the amount is set to 1.2 to 1.6 times and at least the exposed surface of the coextruded molded body extruded from the discharge surface of the extrusion mold is pressed inward by the pressing member. Because it is extrusion molded, the embedded part can be molded without creating a gap between the main body part and the embedded part, even though the embedded part is made of resin with a larger volume change rate with respect to temperature change than the main body part. The occurrence of sink marks (dents) on the exposed surface of the part can also be prevented. In addition, when the discharge amount ratio is simply set in the range of 1.2 to 1.6 times, it is possible to prevent the generation of a gap between the main body portion and the embedded portion, but the open exposed surface of the embedded portion is greatly raised. In the present invention, the exposed surface of the embedded portion is pressed inward by the pressing member in order to regulate the upward bulge of the embedded portion. It is supposed to be co-extruded.

  Hereinafter, the manufacturing method of the present invention will be described using specific embodiments as examples. In this embodiment, a molded body (1) in which long embedded portions (3) and (3) are embedded and integrated in a part of a long main body portion (2) as shown in FIGS. It manufactures by simultaneous extrusion molding using the extrusion die (10) shown in FIG. In this co-extruded body (1), hollow portions (5), (5) and (5) extending in the length direction are formed in parallel in the main body portion (2), and the upper surface of the main body portion (2). Embedded portions (3) and (3) extending in the length direction are respectively embedded above the one end side hollow portion and the other end side hollow portion.

  While the resin constituting the main body (2) uses a resin containing a cellulose material such as wood powder and a thermoplastic resin (hereinafter referred to as "first resin"), the resin constituting the embedded portion (3) A translucent resin containing a phosphorescent agent and a thermoplastic resin (hereinafter referred to as “second resin”) is used. Since the first resin contains a cellulose material such as wood powder having a very small volume change rate with respect to temperature change, the second resin is made of wood powder while the volume change with respect to temperature change is small. Therefore, the volume change rate with respect to the temperature change is larger than that of the first resin.

  Next, an embodiment of an extrusion die (10) used in the production method of the present invention will be described with reference to the drawings (FIGS. 4 to 6). As shown in FIGS. 4 and 5, on the front surface (discharge surface) of the mold (10), a body portion extrusion port (21) having a shape corresponding to the cross-sectional shape of the body portion (2) of the molded body (1). On the other hand, a pair of embedded portion extrusion ports (22) and (22) are arranged at a predetermined interval at an upper position in the body portion extrusion port (21).

  As shown in FIGS. 4 and 6, the main body extrusion port (21) is provided on a side surface of the mold (10) via a first extrusion channel (34) provided in the mold (10). The first extruder connection hole (31) communicates. The first extruder is configured to extrude the first resin at a predetermined extrusion pressure, and the first resin extruded from the first extruder has a first extruder connection hole ( 31) and passes through the first extrusion flow path (34) in order, and is extruded from the body part extrusion port (21) to perform extrusion molding of the body part (2).

  Further, as shown in FIGS. 4 and 6, the buried portion extrusion port (22) is formed on the upper surface of the mold (10) via the second extrusion flow path (35) provided in the mold (10). It communicates with the provided second extruder connection hole (32). The second extruder is configured to extrude the second resin at a predetermined extrusion pressure, and the second resin extruded from the second extruder is a second extruder connection hole ( 32), passing through the second extrusion flow path (35) in order, and being extruded from the buried portion extrusion port (22), the buried portion (3) is extruded.

  Next, FIG. 1 shows an example of a production apparatus used in the method for producing a coextruded product according to the present invention. The extrusion die (10) is attached to the extrusion surface of an extruder (9) composed of a first extruder and a second extruder, and a cooling bath (40) is further arranged at a forward position in the extrusion direction of the extruder (9). Has been. Furthermore, a plate-like pressing member (11) is arranged in a manner connected to the extrusion mold (10) and the cooling tank (40). That is, the plate-like pressing member (11) is fixed in a state where one end side thereof is connected to the discharge surface (10a) of the extrusion mold (10) and the other end side thereof is connected to the side surface of the cooling bath (40). ing. As shown in FIG. 3, a pair of grooves (12) (12) extending along the extrusion direction are provided on the lower surface of the pressing member (11).

  Further, a passage port (not shown) that allows passage of the co-extruded product extruded from the extruder (9) is formed on the side surface of the cooling tank (40) on the side of the extruder (9). The extruded co-extruded product is pushed out while being supported by a support member (41) extending in the horizontal direction from below the passage opening (see FIG. 1). That is, the extruded co-extruded product is extruded and transferred to the downward displacement restricted state by the support member (41) while the upward displacement is restricted by the pressing member (11).

  Therefore, at the time of simultaneous extrusion molding, as shown in FIG. 2, the pressing member (11) comes into contact with the upper surface of the pre-cooling extruded body (7) immediately after being extruded from the extrusion mold (10). That is, the exposed surfaces of the embedded portions (3) and (3) of the extruded body (7) before cooling are in contact with the grooves (12) and (12) of the pressing member (11), respectively, thereby the embedded portion (3 ) The exposed surface of (3) is pressed inward, and thus the upward bulging of the embedded portion (3) is prevented by the pressing member (11).

  Next, the manufacturing method of the coextruded molded body (1) of this invention using the said manufacturing apparatus is demonstrated.

  First, the first resin (a resin containing a cellulose material such as wood powder and a thermoplastic resin) is supplied to the first extruder connected to the first extruder connection hole (31) of the mold (10). On the other hand, the second resin (translucent resin containing a phosphorescent agent and a thermoplastic resin and not containing a cellulose material) is supplied to the second extruder connected to the second extruder connection hole (32). Then, each resin is extruded from each extruder. At this time, the discharge amount (volume) per unit area and unit time of the second resin that constitutes the embedded portion (3) is set as the unit of the first resin that constitutes the main body portion (2). It is set within a range of 1.2 to 1.6 times the discharge amount (volume) per area / unit time.

  Accordingly, the first resin in the heat-melted state is extruded from the main body extrusion port (21) through the first extruder connection hole (31) and the first extrusion flow path (34), while the first resin in the heat-melted state. 2 is extruded from the embedded portion extrusion port (22) through the second extruder connection hole (32) and the second extrusion flow path (35), and the main body made of the first resin by such coextrusion molding. The pre-cooling extruded body (7) in which the embedded portions (3) and (3) made of the second resin are embedded and integrated in a part of the portion (2) is obtained (see FIG. 2). At this time, the discharge amount ratio is set in a range of 1.2 to 1.6 times, and the exposed surface of the embedded portion (3) of the pre-cooling extruded body (7) is pressed by the pressing member (11). Since it will be simultaneously extruded while being pressed inward, it can be molded without creating a gap between the main body part (2) and the embedded part (3), and on the exposed surface of the embedded part (3). Occurrence of dents can also be prevented.

  Further, the discharge amount ratio is set in a range of 1.2 to 1.6 times, and the exposed surface of the embedded portion (3) of the pre-cooled extruded body (7) is internally pressed by the pressing member (11). The second resin expands in the horizontal direction and the downward direction, so that the second resin constituting the embedded portion (3) constitutes the main body portion (2). Since the first resin can be sufficiently pushed into close contact with each other, the fusion bonding property between the embedded portion (3) and the main body portion (2) can be improved.

  In the manufacturing method of the present invention, the unit area / discharge amount (volume) per unit time of the second resin constituting the embedded portion (3) is set to the unit area / first area of the first resin constituting the main body portion (2). It is necessary to set in the range of 1.2 to 1.6 times the discharge amount (volume) per unit time. When the ratio is less than 1.2 times, a gap is generated between the main body (2) and the embedded portion (3), and sink marks are generated on the exposed surface of the embedded portion (3). If it exceeds 1.6 times, the material supply amount of the second resin becomes too large, and the exposed surface of the embedded portion (3) is wrinkled. Among these, the discharge amount (volume) per unit area / unit time of the second resin constituting the embedded portion (3) is set as the discharge amount per unit area / unit time of the first resin constituting the main body portion (2). It is preferable to set in the range of 1.3 to 1.5 times the volume (volume).

  The thermoplastic resin used in the production method of the present invention is not particularly limited, and examples thereof include polyethylene, polypropylene, ABS resin (acrylonitrile-butadiene-styrene copolymer resin), acrylic resin, and polycarbonate. . Among these, it is preferable to use polyethylene as the thermoplastic resin constituting the first resin in terms of improving the extrusion moldability. Further, it is preferable to use polymethyl methacrylate as the thermoplastic resin constituting the second resin, and this can improve the transparency of the embedded portion (3). The afterglow due to the phosphorescent agent can be sufficiently released to the outside, and the visibility can be further improved.

  The cellulose material to be contained in the first resin is not particularly limited, and examples thereof include wood flour, wood flakes, wood fibers, wheat pulp, paper, and other cellulose fiber materials. Among these, it is preferable to use wood flour. In this case, there is an advantage that a wood texture closer to that of natural wood can be imparted.

  The content of the cellulose material in the first resin is preferably 20 to 80% by mass. If the amount is less than 20% by mass, the wood texture cannot be sufficiently imparted, which is not preferable. Among these, the content of the cellulose material in the first resin is more preferably 50 to 70% by mass.

  Various additives such as an antioxidant, an inorganic filler, an ultraviolet absorber, an antistatic agent, and a pigment may be added to the first resin as necessary.

  The phosphorescent agent contained in the second resin is not particularly limited. For example, zinc sulfide-based phosphorescent agent, calcium sulfide-based phosphorescent agent, calcium aluminate-based phosphorescent agent, strontium aluminate-based phosphorescent agent, etc. Can be mentioned.

Examples of the zinc sulfide-based phosphorescent agent include ZnS: Cu (light emission color: yellow green), ZnS: Cu, Co (light emission color: yellow green), and the like. Examples of the calcium sulfide-based phosphorescent agent include CaS: Eu, Tm (light emission color: red), CaS: Bi, and the like. Examples of the calcium aluminate phosphorescent agent include CaAl ₂ O ₄ : Eu, Nd (light emission color: purple blue), CaAl ₂ O ₄ : Eu, Sm, and the like. Examples of the strontium aluminate phosphorescent agent include SrAl ₂ O ₄ : Eu (light emission color: yellow green), Sr ₄ Al ₁₄ O ₂₅ : Eu, Dy (light emission color: blue green), SrAl ₂ O ₄ : Eu, Examples include Dy (emission color: yellowish green), SrAl ₂ O ₄ : Eu, Sn, and the like.

  Note that the phosphorescent agent is a compound having a function of continuously emitting light when receiving light such as sunlight, a fluorescent lamp, or a black light even after irradiation of the light is stopped. This emission is called afterglow.

  The content of the phosphorescent agent in the second resin is preferably set to 1 to 10% by mass. If it is less than 1% by mass, a sufficient amount of afterglow cannot be obtained, and the visibility of the buried portion (3) in the dark is lowered, which is not preferable. On the other hand, if the content exceeds 10% by mass, the transparency of the buried portion (3) is lowered, so that the afterglow due to the phosphorescent agent is not easily released to the outside, which is not preferable. Especially, it is more preferable to set the content rate of the luminous agent in said 2nd resin to 3-10 mass%.

  The second resin may contain various additives such as an antioxidant, an inorganic filler, an ultraviolet absorber, an antistatic agent, and a pigment as long as translucency can be ensured.

  The use of the coextruded molded body (1) produced by the production method of the present invention is not particularly limited, but it can be suitably used for building materials such as handrails, skirting boards, raised ridges, waist boards, deck materials and the like. Moreover, since a coextruded molded object (1) is manufactured by extrusion molding, it can be shape | molded in arbitrary shapes and can be utilized for various uses. Moreover, it is also possible to process and use for a more complicated shape by giving post-processing, such as cutting, to the obtained coextruded molded object (1).

  Next, specific examples of the present invention will be described.

<Example 1>
The coextrusion molded body (1) shown in FIG. 7 was manufactured by the manufacturing method mentioned above using the manufacturing apparatus which consists of the structure shown in FIG. 1 comprised using the extrusion die (10) shown in FIG. That is, the molded body (1) in which the long embedded portions (3) and (3) were embedded in a part of the upper surface of the long main body portion (2) as shown in FIG. 7 was manufactured. The first resin (resin consisting of 40 parts by mass of polyethylene and 60 parts by mass of wood flour having an average particle size of 150 μm) is extruded from the body part extrusion port (21) of the extrusion mold (10), while the embedded part extrusion port (22 ) Was extruded at the same time by extruding a second resin (translucent resin consisting of 95 parts by weight of polymethyl methacrylate and 5 parts by weight of phosphorescent agent). At this time, the discharge amount ratio (unit area of second resin / discharge amount per unit time / unit area of first resin / discharge amount per unit time) was set to 1.4. The strontium aluminate-based phosphorescent agent was used as the phosphorescent agent.

  The width (t) of the embedded portion extrusion port (22) of the extrusion mold (10) was 4 mm, and the width (m) of the groove (12) of the pressing member (11) was 8 mm. Further, the width (n) of the embedded portion (3) in the extruded molded body (7) before cooling immediately after extrusion is 4 mm, and the width (r) of the embedded portion (3) in the coextruded molded body (1) obtained by cooling. ) Was 7.5 mm.

<Example 2>
A coextruded article (1) was produced in the same manner as in Example 1 except that the discharge amount ratio was set to 1.32.

<Example 3>
A coextruded article (1) was produced in the same manner as in Example 1 except that the discharge amount ratio was set to 1.46.

<Example 4>
A coextruded article (1) was produced in the same manner as in Example 1 except that a resin composed of 40 parts by mass of polyethylene and 60 parts by mass of wheat pulp was used as the first resin.

<Example 5>
As the first resin, a resin comprising 50 parts by mass of polypropylene and 50 parts by mass of wood flour having an average particle size of 150 μm is used. As the second resin, 93 parts by mass of polycarbonate and 7 parts by mass of a phosphorescent agent are used. A coextruded product (1) was produced in the same manner as in Example 1 except that the resin was used.

<Comparative Example 1>
A coextruded product was produced in the same manner as in Example 1 except that the discharge amount ratio was set to 1.15.

<Comparative example 2>
A coextruded product was produced in the same manner as in Example 1 except that the discharge amount ratio was set to 1.65.

  None of the co-extruded bodies produced in Examples 1 to 5 have a gap between the main body (2) and the embedded portion (3), and there are sink marks (dents) on the exposed surface of the embedded portion (3). It did not occur and had a good appearance.

  On the other hand, in the coextruded molded body of Comparative Example 1 manufactured by setting the discharge amount ratio to be smaller than the specified range of the present invention, there was a gap between the main body portion and the embedded portion, There was also a sink (dent) on the exposed surface of the part. Further, in the co-extruded product of Comparative Example 2 manufactured by setting the discharge amount ratio to be larger than the specified range of the present invention, noticeable wrinkles are formed on the exposed surface of the embedded portion due to the duplication of the second resin. It was.

It is a side view which shows schematic structure of the apparatus used with the manufacturing method of this invention. It is sectional drawing of the XX line in FIG. (A) is a top view of a pressing member, (b) is a front view of a pressing member. It is a front side perspective view which shows the metal mold | die used with the manufacturing method of this invention. It is sectional drawing of the AA in FIG. It is sectional drawing of the BB line in FIG. It is a perspective view which shows the coextruded molded object manufactured with the manufacturing method of this invention. It is sectional drawing of the CC line in FIG. It is sectional drawing of the coextruded molded object manufactured by the conventional general coextrusion method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Simultaneous extrusion molded object 2 ... Main-body part 3 ... Embedded part 10 ... Extrusion metal mold 11 ... Holding member 21 ... Main-body part extrusion port 22 ... Embedded-part extrusion port

Claims (10)

Molding in which a buried portion made of a second thermoplastic resin having a volume change rate with respect to a temperature change larger than that of the first thermoplastic resin is embedded and integrated in a part of the main body portion made of the first thermoplastic resin. When manufacturing the body by coextrusion using an extrusion die,
The discharge amount per unit area / unit time of the second thermoplastic resin from the extrusion mold is 1.2 of the discharge amount per unit area / unit time of the first thermoplastic resin from the extrusion mold. Set to a range of ~ 1.6 times,
Simultaneously in a state where at least the exposed surface of the embedded portion of the co-extruded product extruded from the discharge surface of the extrusion mold is pressed inward by a pressing member fixed in a state of being connected to the discharge surface of the extrusion mold. A method for producing a coextruded product, characterized by performing extrusion molding.   The discharge amount per unit area / unit time of the second thermoplastic resin from the extrusion mold is 1.3% of the discharge amount per unit area / unit time of the first thermoplastic resin from the extrusion mold. The method for producing a coextruded article according to claim 1, wherein the coextruded article is set in a range of ~ 1.5 times. A part of the main body made of the first resin containing a cellulose material such as wood powder and a thermoplastic resin is a translucent second resin containing a thermoplastic resin and has a volume change rate with respect to a temperature change. When manufacturing a molded body in which an embedded portion made of a second resin larger than the first resin is embedded and integrated using an extrusion die by simultaneous extrusion molding,
The discharge amount per unit area / unit time of the second resin from the extrusion mold is 1.2 to 1.6 of the discharge amount per unit area / unit time of the first resin from the extrusion mold. Set to double the range,
Simultaneously in a state where at least the exposed surface of the embedded portion of the co-extruded product extruded from the discharge surface of the extrusion mold is pressed inward by a pressing member fixed in a state of being connected to the discharge surface of the extrusion mold. A method for producing a coextruded product, characterized by performing extrusion molding.   The discharge amount per unit area / unit time of the second resin from the extrusion mold is 1.3 to 1.5 of the discharge amount per unit area / unit time of the first resin from the extrusion mold. The method for producing a coextruded product according to claim 3, wherein the coextruded product is set in a double range.   The method for producing a coextruded product according to claim 3 or 4, wherein the second resin contains a phosphorescent agent.   The method for producing a coextruded product according to claim 5, wherein the content of the phosphorescent agent in the second resin is 1 to 10% by mass.   The method for producing a coextruded product according to any one of claims 3 to 6, wherein a content of the cellulose material in the first resin is 20 to 80% by mass.   The method for producing a coextruded product according to any one of claims 3 to 7, wherein wood powder is used as the cellulose material.   The coextrusion molding according to any one of claims 3 to 8, wherein polyethylene is used as the thermoplastic resin constituting the first resin, and polymethyl methacrylate is used as the thermoplastic resin constituting the second resin. Body manufacturing method.   A coextruded article produced by the production method according to claim 1.

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