JP2013244689A - Method of manufacturing resin molded body and siding material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a resin molded body and a siding material, which can be manufactured with high quality and high productivity while preventing a manufacturing facility from being excessively enlarged.SOLUTION: A method of manufacturing a siding material having a resin molded body 12 includes a melt extrusion step of extruding molten resin P in the shape of the resin molded body 12, and a cooling step of cooling the molten resin P and obtaining the resin molded body 12. The cooling step includes a first cooling step of depressurizing a periphery of the molten resin P and cooling it while maintaining the shape of the molten resin P by a first cooling means 40, a second cooling step of bringing the molten resin P into contact with a refrigerant and cooling it by a second cooling means 42, and a third cooling step of depressurizing the periphery of the molten resin P and cooling it while maintaining the shape of the molten resin P by a third cooling means 44.

Description

  The present invention relates to a resin molded body and a method for producing a siding material.

  As exterior decorative materials for outer walls of buildings and structures, for example, ceramic siding materials, metal siding materials, and synthetic resin siding materials are known. Ceramic siding materials are excellent in strength and coatability. However, ceramic siding materials are prone to cracking in cold regions because they are repeatedly expanded and contracted by freezing and thawing of water contained in concrete. Further, the metal siding material has a problem of rust due to salt damage. On the other hand, synthetic resin-based siding materials made of synthetic resin such as vinyl chloride resin are excellent in durability, resistant to rust due to salt damage, cracking due to repeated freezing and thawing, and excellent water repellency and impact resistance. In addition, it is lightweight and has good workability.

  As the synthetic resin siding material, a material formed of a resin molded body having a substrate and protruding portions such as ribs protruding from the substrate is widely used. As a method for producing such a synthetic resin siding material, for example, a molten resin shaped into a predetermined shape is continuously extruded from a mold for extrusion molding, and the molten resin extruded from the mold is cooled. A method of cutting to a predetermined dimension is known (for example, Patent Document 1). As a means for cooling the molten resin, a sizer that can be cooled while maintaining the shape of the molten resin by reducing the pressure around the molten resin is widely used to prevent the molten resin from being greatly deformed by shrinkage due to cooling.

JP 11-138633 A

  However, in the conventional manufacturing method as described in Patent Document 1, it takes a long time to sufficiently cool the molten resin extruded from the mold, so that the productivity is insufficient. Further, since the cooling means tends to be long to sufficiently cool the molten resin, there is a problem that the manufacturing equipment becomes excessive.

  An object of this invention is to provide the manufacturing method of the resin molding which is excellent in productivity, and can suppress that manufacturing equipment becomes excessive, and the manufacturing method of a siding material.

The method for producing a resin molded body of the present invention is a method for producing a resin molded body having a substrate and a projecting portion projecting from the substrate,
A melt extrusion step of extruding a molten resin into the shape of the resin molding,
A cooling step of cooling the molten resin extruded in the melt extrusion step to obtain the resin molded body while maintaining its shape,
The cooling step is a first cooling step of cooling the molten resin while reducing the pressure around the molten resin and maintaining the shape of the molten resin;
After the first cooling step, a second cooling step of cooling the molten resin by bringing a refrigerant into contact therewith,
And a third cooling step of cooling the molten resin while maintaining the shape of the molten resin by reducing the pressure around the molten resin after the second cooling step. .

Further, the method for producing a siding material of the present invention is a method for producing a siding material having a substrate and a resin molding having a projecting portion projecting from the substrate,
A melt extrusion step of extruding a molten resin into the shape of the resin molding,
A cooling step of cooling the molten resin extruded in the melt extrusion step to obtain the resin molded body while maintaining its shape,
The cooling step is a first cooling step of cooling the molten resin while reducing the pressure around the molten resin and maintaining the shape of the molten resin;
After the first cooling step, a second cooling step of cooling the molten resin by bringing a refrigerant into contact therewith,
And a third cooling step of cooling the molten resin while maintaining the shape of the molten resin by reducing the pressure around the molten resin after the second cooling step. .

According to the method for producing a resin molded body of the present invention, a high-quality resin molded body can be produced with excellent productivity, and the production facility can be prevented from becoming excessive.
Moreover, according to the manufacturing method of the siding material of this invention, a high quality siding material can be manufactured with the outstanding productivity, and it can also suppress that manufacturing facilities become excessive.

It is the schematic diagram which showed an example of the manufacturing apparatus used for the manufacturing method of the siding material of this invention. It is the perspective view which showed an example of the cooling means used for the manufacturing method of the siding material of this invention. It is sectional drawing when the 1st cooling means of FIG. 2 is cut | disconnected by the straight line I-I '. It is sectional drawing when the 1st cooling means of FIG. 2 is cut | disconnected by the straight line II-II '. It is the side view which showed an example of the siding material manufactured with the manufacturing method of this invention. It is the front view which looked at the siding material of FIG. 5 from the surface side. It is the rear view which looked at the siding material of FIG. 5 from the back surface side.

Hereinafter, a method for manufacturing the siding material 10 illustrated in FIGS. 5 to 7 will be described as an example of the method for manufacturing the siding material of the present invention.
(Siding material)
In this specification, “the surface of the siding material” is the surface that becomes the outdoor side when the siding material is attached to the outer wall of the building, etc., and the “back surface of the siding material” is the opposite side, that is, the building side. It is a surface. In addition, “upper” at the upper edge, upper end, and the like of the siding material means a side that becomes an upper side when the siding material is attached to an outer wall of a building.

As shown in FIGS. 5 to 7, the siding material 10 includes a synthetic resin resin molded body 12 and a design layer 14 formed on the surface of the resin molded body 12. The resin molded body 12 includes a rectangular substrate 16, an upper projecting portion 18 projecting above the substrate 16, a lower projecting portion 20 projecting below the substrate 16, and the back side of the substrate 16. And two rear side projecting portions 22, 22 projecting from each other.
The upper projecting portion 18 includes an upper end surface portion 24 that extends perpendicularly from the upper end of the substrate 16 to the surface of the substrate 16 and on the opposite side of the design layer 14 side, and an upper end surface portion 24 that is opposite to the substrate 16 side. An upper edge 26 extending in parallel to the surface of the substrate 16 from the end and opposite to the substrate 16 side, and a protrusion protruding from the design layer 14 side on the upper surface of the upper end surface portion 24 to the side opposite to the substrate 16 side. It consists of Article 28. The lower protruding portion 20 protrudes perpendicularly from the vicinity of the lower end of the substrate 16 to the side opposite to the design layer 14 side, and bends perpendicularly to the lower end direction of the substrate 16 in the middle. The groove portion 30 is formed by 16. Two back side protruding portions 22 are provided in the vicinity of the center of the back surface of the substrate 16 along the horizontal direction (long side direction).

As shown in FIGS. 6 and 7, the upper edge portion 26 of the upper projecting portion 18 is provided with a plurality of attachment holes 26 a for attaching the siding material 10 to an attachment surface such as an outer wall of a building. The siding material 10 can be fixed to the mounting surface by bringing the back surface of the upper edge 26 into contact with the mounting surface and screwing, nailing or the like using the mounting hole 26a.
Further, when the plurality of siding materials 10 are continuously attached to the attachment surface in the vertical direction, the groove portion 30 of the siding material 10 and the ridge 28 of the other siding material 10 attached to the lower side thereof are engaged, The upper and lower siding materials 10 are not easily separated.
Further, when the siding material 10 is attached to the attachment surface, not only the back surface of the upper edge portion 26 of the upper protrusion portion 18 but also the tip surface of the rear protrusion portion 22 contacts the attachment surface, and the substrate 16 is stably supported. It has come to be.

The synthetic resin constituting the resin molded body 12 is preferably a thermoplastic resin from the viewpoint of moldability and the like. Examples of the thermoplastic resin include polyolefin resins such as vinyl chloride resin, polycarbonate resin, polyethylene, and polypropylene. Of these, vinyl chloride resin is preferred in that it has moisture permeability and hardly undergoes freezing destruction and has high resistance to salt damage, acid and alkali.
The synthetic resin may be blended with additives such as fillers, reinforcing materials, pigments, processing aids, heat stabilizers, and ultraviolet absorbers as necessary.

The design layer 14 is a layer that is formed on the surface side of the substrate 16 and imparts excellent design properties. For example, a primer layer and a resin that is formed on the primer layer and in which inorganic particles are dispersed in a synthetic resin. A laminate having a three-layer structure comprising an intermediate coating layer formed of the composition and a topcoat layer formed on the intermediate coating layer is exemplified. A design (grain pattern or the like) is imparted to the design layer 14 depending on the type and size of the inorganic particles contained in the intermediate coating layer, the dispersed state, and the like.
Examples of the synthetic resin used for the intermediate coating layer include acrylic resin, silicone resin, urethane resin, and fluorine resin.
Examples of the inorganic particles include natural crushed stones, pebbles, mica, silica sand, glass, colored aggregates, ceramic chips (chromium oxide, titanium oxide, zirconium oxide, aluminum oxide, tungsten carbide, chromium carbide, etc.). Can be mentioned.

(manufacturing device)
Hereinafter, the manufacturing apparatus 1 used for the manufacturing method of the siding material 10 is demonstrated based on FIGS.
As shown in FIG. 1, the manufacturing apparatus 1 is provided on an extruder 2 that continuously extrudes a molten resin obtained by melting a synthetic resin that forms a resin molded body 12 of a siding material 10, and on the tip side of the extruder 2. The molten resin to be extruded is obtained by being cooled by the mold 3 that shapes the cross-sectional shape equivalent to that of the resin molded body 12, the cooling means 4 that cools the molten resin P that is extruded from the mold 3, and the cooling means 4. Take-up means 5 for taking up the resin molded body 12, cutting means 6 for cutting the resin molded body 12 taken up by the take-up means 5 into predetermined dimensions, and decorating means for decorating the surface of the substrate 16 in the cut resin molded body 12. 7.

  As the extruder 2 and the mold 3, an extruder and a mold used for extrusion molding of a resin molded body having a substrate and a projecting portion such as a synthetic resin siding material can be used without particular limitation.

  As shown in FIGS. 1 and 2, the cooling unit 4 includes a first cooling unit 40 that cools the molten resin P extruded from the mold 3 under reduced pressure, and a refrigerant that is added to the molten resin P after the first cooling unit 40. The second cooling means 42 that cools by contacting with 42a, and the third cooling means 44 that cools the molten resin P under reduced pressure after the second cooling means 42 are provided.

  As shown in FIGS. 3 and 4, the first cooling means 40 includes a resin passage 46 through which the molten resin P extruded from the mold 3 passes, and a decompression means (not shown) that makes the inside of the resin passage 46 a decompression condition. Are connected to each other, and a refrigerant channel 50 through which a refrigerant flows is provided.

The resin passage 46 has a cross-sectional shape that is similar to the cross-sectional shape when the cross section of the resin passage 46 is perpendicular to the flow direction of the molten resin and cut along a plane perpendicular to the MD direction in the resin molded body 12. That is, the resin passage 46 has a cross-sectional shape such that when the molten resin P pushed out from the mold 3 passes, the distance between the molten resin P and the inner wall surface of the resin passage 46 is the same throughout. It has become.
The distance between the inner wall surface of the resin passage 46 and the molten resin P passing through the resin passage 46 can be set as appropriate, and is preferably 15 to 100 mm.

Two suction channels 48 are provided on each of the upper wall surface 46 a side and the lower wall surface 46 b side of the resin passage 46. Further, as shown in FIG. 2, pipes 52 are connected to the suction flow path 48, and a pressure reducing means such as a pump is connected to the suction flow path 48. Thereby, in the 1st cooling means 40, it draws in through the suction flow path 48 from both the upper side and lower side of the flat molten resin P, and the inside of the resin passage 46 is decompressed uniformly.
When the molten resin P extruded from the mold 3 is cooled and solidified, the shape may be deformed by the influence of shrinkage. By cooling the molten resin P in a state where the pressure in the resin passage 46 is reduced, the molten resin P can be cooled while maintaining the shape shaped by the mold 3.
The number and positions of the suction channels 48 are not particularly limited as long as they can be uniformly reduced in the resin passage 46 under a predetermined pressure reduction condition.

As shown in FIG. 3, two refrigerant channels 50 are provided in total, two on the upper side of the resin passage 46 and two on the lower side of the resin passage 46. Further, as shown in FIG. 2, pipes 54 are respectively connected to the refrigerant flow path 50, and the refrigerant flows through the refrigerant flow path 50 through the pipe 54.
As shown in FIG. 4, the two refrigerant flow paths 50 on the upper side of the resin passage 46 are respectively provided on the one side surface 40 a side and the other side surface 40 b side of the first cooling means 40. The shape is meandering from the third side toward the second cooling means 42 side. In this example, in any refrigerant flow path 50, the refrigerant is supplied from the mold 3 side into the first cooling means 40, and after the refrigerant meanders toward the second cooling means 42, the second cooling means 42 side. It comes to be discharged from.
The two refrigerant flow paths 50 below the resin passage 46 have the same form as the two refrigerant flow paths 50 above the resin passage 46.

As shown in FIG. 2, the second cooling means 42 is provided between the first cooling means 40 and the third cooling means 44, and the refrigerant is brought into contact with the molten resin P coming out of the first cooling means 40. It has become so.
The form of the second cooling means 42 is not particularly limited as long as the refrigerant comes into contact with the molten resin P. In this example, a bowl-like shape is provided between the first cooling means 40 and the third cooling means 44. The 2nd cooling means 42 is provided and the molten resin P contacts a refrigerant | coolant by advancing in a refrigerant | coolant. The refrigerant is supplied from above the molten resin P through a pipe (not shown), and is replaced at any time by being discharged through another pipe (not shown).

The third cooling means 44 is the same mode as the first cooling means 40.
That is, in the third cooling unit 44, similarly to the first cooling unit 40, a resin passage through which the molten resin P passes and a decompression unit (not shown) that makes the inside of the resin passage a decompression condition are connected via the pipe 56. The suction channel and the refrigerant channel through which the pipe 58 is connected and through which the refrigerant flows are provided.
As the 1st cooling means 40 and the 3rd cooling means 44, the well-known sizer which can cool, for example, can reduce the pressure around the molten resin is employable.

The take-up means 5 is not particularly limited as long as the resin molded bodies 12 obtained by cooling by the cooling means 4 can be taken up sequentially.
The cutting means 6 is not particularly limited as long as it can cut the taken resin molded body 12 into a predetermined size.
The decorating means 7 may be any as long as it can form the predetermined design layer 14. Examples of the decorating means 7 include a coating apparatus capable of coating various paints, a drying furnace, and the like.

(Production method)
Hereinafter, the manufacturing method of the siding material 10 is demonstrated as an example of the manufacturing method of the siding material of this invention. Examples of the method for producing the siding material 10 include a method having the following melt extrusion process, cooling process, cutting process, and decorating process.
Melt extrusion process: The molten resin obtained by melting the synthetic resin forming the resin molded body 12 is continuously extruded by the extruder 2 and the mold 3 while being shaped into a cross-sectional shape equivalent to the cross-sectional shape of the resin molded body 12. Process.
Cooling step: a step of cooling the molten resin P extruded from the mold 3 while maintaining the shape by the cooling means 4 to form the resin molded body 12.
Cutting step: a step of cutting the resin molded body 12 into a predetermined dimension.
Decoration process: The process of forming the design layer 14 in the surface of the board | substrate 16 in the resin molding 12 after a cutting | disconnection.

(Melting extrusion process)
The extruded resin 2 and the mold 3 are used to extrude a molten resin obtained by heating the synthetic resin forming the resin molded body 12 to a melting temperature or higher so that the cross-sectional shape thereof becomes the cross-sectional shape of the resin molded body 12. At this time, the synthetic resin may be foamed to form a foam. Thereby, the resin molding 12 can be reduced in weight.
Examples of the method for foaming the synthetic resin include a method in which an inorganic foaming agent (such as carbonate) or an organic foaming agent (thermal decomposition type or reaction type) is added and heated to the decomposition temperature to generate gas. It is done.

(Cooling process)
The molten resin P pushed out from the mold 3 by the cooling means 4 is cooled while the shape is maintained to obtain a resin molded body 12. In the present embodiment, the cooling process includes the following first cooling process, second cooling process, and third cooling process.
First cooling step: a step of cooling the molten resin P while maintaining the shape of the molten resin P by reducing the pressure around the molten resin P extruded from the mold 3 in the first cooling means 40.
Second cooling step: After the first cooling step, the second cooling means 42 cools the molten resin P by bringing the refrigerant into contact therewith.
Third cooling step: A step of cooling the molten resin P while maintaining the shape of the molten resin P by reducing the pressure around the molten resin P in the third cooling means 44 after the second cooling step.

First cooling step:
In the first cooling means 40, the molten resin P pushed out from the mold 3 is decompressed in the resin passage 46 by a suction means such as a pump through the suction flow path 48, and the refrigerant is circulated through the refrigerant flow path 50. It passes through the resin passage 46. As described above, the molten resin P is cooled in a state where the pressure around the molten resin P is reduced in pressure, so that the shape of the molten resin P is prevented from being deformed by contraction due to cooling.

  The decompression condition (pressure in the resin passage 46) around the molten resin P in the first cooling step is preferably 0.02 to 0.07 MPa, and more preferably 0.04 to 0.06 MPa. If the decompression condition is equal to or higher than the lower limit value, it is easy to suppress deformation of the shape of the molten resin P due to the influence of shrinkage due to cooling. If the decompression condition is less than or equal to the upper limit value, there will be no waviness or rib sinks, and deformation of the shape can be suppressed.

  10-35 degreeC is preferable and the temperature of the refrigerant | coolant in a 1st cooling process has more preferable 15-30 degreeC. If the temperature of a refrigerant | coolant is more than a lower limit, the cooling efficiency of the molten resin P is high. If the temperature of a refrigerant | coolant is below an upper limit, it will be easy to suppress that the shape of the molten resin P deform | transforms by the influence of the shrinkage | contraction by cooling.

The cooling time in the first cooling step is preferably 10 to 30 seconds, and more preferably 18 to 22 seconds. If cooling time is more than a lower limit, it will become low enough to the extent that the temperature of molten resin P does not shrink | contract greatly. If the cooling time is less than or equal to the upper limit value, it can be cooled in a short time and productivity is high.
In the first cooling step, the molten resin P is preferably cooled until the temperature of the molten resin P becomes the flexible temperature of the molten resin P. Thereby, it becomes easy to suppress the deformation | transformation in a cooling process and to obtain the high-quality resin molding 12 with high productivity.

Second cooling step:
In the second cooling means 42, the molten resin P is cooled by bringing the refrigerant into contact with the molten resin P that has come out of the first cooling means 40.
10-35 degreeC is preferable and, as for the temperature of the refrigerant | coolant made to contact molten resin P in a 2nd cooling process, 15-30 degreeC is more preferable. If the temperature of a refrigerant | coolant is more than a lower limit, the cooling efficiency of the molten resin P is high. If the temperature of a refrigerant | coolant is below an upper limit, it will be easy to suppress that the shape of the molten resin P deform | transforms by the influence of the shrinkage | contraction by cooling.

The cooling time in the second cooling step is preferably 5 to 20 seconds, and more preferably 8 to 12 seconds. If cooling time is more than a lower limit, the temperature of molten resin P will become low enough. If the cooling time is less than or equal to the upper limit value, it can be cooled in a short time and productivity is high.
In the second cooling step, it is preferable that the molten resin P is cooled until the temperature of the molten resin P becomes the flexible temperature of the molten resin P. Thereby, it becomes easy to obtain a high-quality resin molded body 12 with high productivity while suppressing deformation in the cooling process.

Third cooling step:
In the third cooling unit 44, the molten resin P sent from the second cooling unit 42 is decompressed in the resin passage by the suction unit such as a pump through the suction channel and the refrigerant is circulated through the refrigerant channel. Pass through the resin passage. In this way, the molten resin P is further cooled and the resin molded body 12 is formed while suppressing the deformation of the molten resin P due to shrinkage due to cooling.

  The decompression condition (pressure in the resin passage) around the molten resin P in the third cooling step is preferably 0.02 to 0.07 MPa, and more preferably 0.04 to 0.06 MPa. If the decompression condition is equal to or higher than the lower limit value, it is easy to suppress deformation of the shape of the molten resin P due to the influence of shrinkage due to cooling. If the decompression condition is less than or equal to the upper limit value, undulations and ribs are eliminated, and deformation of the shape is suppressed.

  10-35 degreeC is preferable and the temperature of the refrigerant | coolant in a 3rd cooling process has more preferable 15-30 degreeC. If the temperature of a refrigerant | coolant is more than a lower limit, the cooling efficiency of the molten resin P is high. If the temperature of a refrigerant | coolant is below an upper limit, it will be easy to suppress that the shape of the molten resin P deform | transforms by the influence of the shrinkage | contraction by cooling.

The cooling time in the third cooling step is preferably 10 to 30 seconds, and more preferably 18 to 22 seconds. If cooling time is more than a lower limit, it will become low enough to the extent that the temperature of molten resin P does not shrink | contract greatly. If the cooling time is less than or equal to the upper limit value, it can be cooled in a short time and productivity is high.
In the third cooling step, cooling is preferably performed until the temperature of the molten resin P reaches 20 to 50 ° C. Thereby, it becomes easy to obtain a high-quality resin molded body 12 with high productivity while suppressing deformation in the cooling process.

The cooling time in the first cooling process to the third cooling process can be adjusted by the lengths of the first cooling means 40, the second cooling means 42, and the third cooling means 44 and the take-up speed of the resin molded body 12 by the take-up means 5.
The take-up speed of the resin molded body 12 by the take-up means 5 is preferably 50 to 200 cm / min, and more preferably 70 to 100 cm / min.

(Cutting process)
The resin molded body 12 taken from the cooling means 4 by the taking means 5 is cut to a predetermined size by the cutting means 6.

(Decoration process)
The design layer 14 is formed on the surface side of the substrate 16 in the resin molded body 12 by the decorating means 7. The method for forming the design layer 14 may be selected as appropriate depending on the type of the design layer 14 to be formed, and is not particularly limited.
For example, in the case where a primer layer, an intermediate coating layer formed of a resin composition in which inorganic particles are dispersed in a synthetic resin, and a design layer having a three-layer structure including a topcoat layer are formed on the surface of the substrate 16, the following A method is mentioned.
First, a primer agent is applied to the surface of the substrate 16 and dried to form a primer layer. Thereafter, a mixture of the synthetic resin emulsion and the inorganic particles forming the intermediate coating layer is applied on the primer layer and dried to form the intermediate coating layer. Further, a coating material in which a transparent resin (acrylic-silicon resin, fluorine resin, etc.) for forming the topcoat layer is dissolved or dispersed in a solvent is applied and dried to form the topcoat layer.

The method for applying the primer and the coating used for forming the topcoat layer is not particularly limited, and coating by roll coater, knife coater, or reciprocating spraying is preferable.
Moreover, the coating method of the mixture of the synthetic resin emulsion and the inorganic particles is not particularly limited, and coating by roll coater, knife coater, or gun spraying is preferable.
The drying method of each layer is not specifically limited, For example, drying with a drying furnace etc. are mentioned.

  In addition, in the formation of the intermediate coating layer, if necessary, after applying the mixture, and before drying the formed coating layer, the surface of the coating layer is subjected to trowel finish, roller finish, etc. (Striated, indefinite shape, etc.) may be formed.

  In the siding material manufacturing method of the present invention described above, after the molten resin is cooled to some extent while suppressing deformation under reduced pressure conditions in the first cooling step, it is melted by contacting the refrigerant in the second cooling step. Since the resin is efficiently cooled and further cooled while maintaining the shape under reduced pressure in the third cooling step, the resin can be cooled in a short time while suppressing deformation of the molten resin. Therefore, it is possible to manufacture a siding material having a high-quality resin molded body with high productivity, and it is possible to suppress an excessive increase in manufacturing equipment.

  In addition, the manufacturing method of the siding material of this invention is not limited to an above described method. For example, the method which does not have a decoration process may be sufficient. Moreover, the manufacturing method of the siding material which has the resin molded object of a different shape may be sufficient.

  The manufacturing method of the resin molding of this invention is a method which has an above described melt extrusion process and a cooling process. The manufacturing method of the resin molding of this invention is not limited to the manufacturing method of a siding material. For example, the manufacturing method of the resin molding for uses, such as a deck material and an interior material, may be sufficient.

  DESCRIPTION OF SYMBOLS 1 ... Manufacturing apparatus, 2 ... Extruder, 3 ... Mold, 4 ... Cooling means, 5 ... Taking-out means, 6 ... Cutting means, 7 ... Decorating means, DESCRIPTION OF SYMBOLS 10 ... Siding material, 12 ... Resin molding, 14 ... Design layer, 16 ... Board | substrate, 18 ... Upper protrusion part, 20 ... Lower protrusion part, 22 ...・ Back side protruding portion, 24... Upper end surface portion, 26... Upper edge portion, 28... Ridge, 30 .. groove portion, 40. Means, 42a ... refrigerant, 44 ... third cooling means.

Claims (2)

A method for producing a resin molded body having a substrate and a projecting portion projecting from the substrate,
A melt extrusion step of extruding a molten resin into the shape of the resin molding,
A cooling step of cooling the molten resin extruded in the melt extrusion step to obtain the resin molded body while maintaining its shape,
The cooling step is a first cooling step of cooling the molten resin while reducing the pressure around the molten resin and maintaining the shape of the molten resin;
After the first cooling step, a second cooling step of cooling the molten resin by bringing a refrigerant into contact therewith,
And a third cooling step of cooling the molten resin while maintaining the shape of the molten resin by reducing the pressure around the molten resin after the second cooling step. Manufacturing method. A method of manufacturing a siding material having a substrate and a resin molded body having a protruding portion protruding from the substrate,
A melt extrusion step of extruding a molten resin into the shape of the resin molding,
A cooling step of cooling the molten resin extruded in the melt extrusion step to obtain the resin molded body while maintaining its shape,
The cooling step is a first cooling step of cooling the molten resin while reducing the pressure around the molten resin and maintaining the shape of the molten resin;
After the first cooling step, a second cooling step of cooling the molten resin by bringing a refrigerant into contact therewith,
And a third cooling step for cooling the molten resin while maintaining the shape of the molten resin by reducing the pressure around the molten resin after the second cooling step. Production method.

Images