JP5338001B1 - Plastic sheet molding method and molding apparatus - Google Patents

Abstract

A method and apparatus for forming a plastic sheet having a plurality of convex shapes on one side of a sheet are provided. A molten resin 11c extruded flatly from a T die 11b of an extruder 11a is passed through a through hole 15a. Extrusion is performed so as to be sandwiched between the rotating annular belt-shaped mold 15 and the sheet base forming roll 12b, and the sheet portion 16b and the convex portion 16b of the plastic sheet 16 are simultaneously formed. A method and apparatus for molding a plastic sheet that enables air venting and molding of the convex portion 16a with high accuracy.
[Selection] Figure 1

Description

  The present invention relates to a molding method and a molding apparatus for a plastic sheet comprising a sheet portion and a plurality of convex portions provided on one surface of the sheet portion.

  Plywood panels and metal floors were used as floorboards that were laid on mud or sandy slippery ground surfaces. The plywood is light but cannot withstand long-term use. Metal floor boards can withstand long-term use but are heavy and have problems with workability and safety. Therefore, there has been a growing demand for a base plate that is light and elastic and can withstand repeated use over a long period of time, and a plastic base plate has been proposed.

  A molding method and a molding apparatus for a plastic sheet (plastic base plate) having a convex portion on the surface have been proposed. There are four types of molding methods or molding apparatuses including similar technologies.

  The first type is a generally practiced method, and the extruded masses of plastic in the melted state are placed on a press mold and compressed to form the masses. A method of forming a convex pattern.

The second type is a surface treatment method for a wood-like molded article, which is a surface treatment method for a wood-like molded article obtained by mixing a resin with a pulverized product obtained by pulverizing a cellulose material, and melting and extruding the resin. A method of embossing the surface of a molded product. It is a shallow embossing that represents a wood grain pattern.
For example, it is disclosed in Patent Document 2.

  The third type is a pair of pressing belts, at least one of which is composed of an embossing belt, for example, a pair of pressing belts composed of an embossing belt and a pressing belt before the extruded thermoplastic resin sheet is completely cooled. The emboss is formed on the resin sheet by being fed in between and pressed by the pair of pressing belts. For example, it is disclosed in Patent Document 1. As in the example of this patent document, it is a very shallow embossing with a skin wrinkle pattern with a depth of 300 μm.

The fourth type is a rugged pattern on the surface of a material to be transferred by pressing and heating a belt-shaped mold having a fine concavo-convex pattern to the transferred material in a cold state and then peeling the mold from the material to be transferred. A pattern transfer method for transferring a pattern. There are a method including a cylindrical pressure mechanism, an apparatus and a method including a mechanism for pressing the mold and the material to be transferred, and the like.
For example, it is disclosed in Patent Document 3 and Patent Document 4. These patents relate to the transfer of nano-order uneven patterns.

JP-A-8-207137 Japanese Patent Laid-Open No. 10-272695 JP 2009-158731 A International Publication No. 2011/088986 Pamphlet

  However, the first type, for example, appears to have melted and integrated into one another after 4 or 6 plastic masses that have been extruded and melted are pressed, but are melted and fully integrated. It has not been. Therefore, there is a defect in quality such as a crack generated from the welded part during use as a floorboard.

  The second type is suitable for embossing with a shallow and fine wood grain, but is not suitable for forming a tall convex as a floorboard. Moreover, since it is an embossing method by the post-process of the molded product once extruded, even if embossing with a high convex part is performed immediately after extrusion, it becomes embossing by a heated roll, and from the roll mold Since the molded product is immediately released, the molded embossed portion cannot be cooled, and the shape of the molded convex portion cannot be maintained.

  The third type is a method of embossing a once extruded thermoplastic sheet, and it is possible to emboss a thin resin sheet with a depth of about 300 μm as in the example, but the thickness is After extruding a plastic sheet (about 3mm to 30mm), it is impossible to emboss a relatively large convex part of about 1 to 10mm because the resin surface is hard even though it is not completely cooled. is there.

  In addition, the fourth type is a method of transferring nano-order fine irregularities to a roll-thinned thin sheet after being extruded, and by pressing and heating a sheet that has already been cooled. Although it is possible to transfer nano-order fine irregularities, it is impossible to form a relatively large convex portion of about 1 to 10 mm on the surface of a plastic sheet having a thickness of about 3 to 30 mm.

  In the methods of Patent Document 1, Patent Document 3, and Patent Document 4 of the prior art, a method using a belt-shaped mold is used. However, once the extruded sheet is reheated and pressed, nano-order transfer or several hundred μm is performed. This technology enables embossing, and large convex parts cannot be molded with high quality.

  In view of the above technical problems, it is an object of the present invention to provide a method and apparatus for molding a plastic sheet having a relatively large high-quality convex portion.

  To form a relatively large convex part on the surface of a plastic sheet, a molten resin extruded flat from a T-die is sandwiched between a belt-shaped mold having a through hole and a sheet base forming roll, and a sheet of plastic sheet We paid attention to the simultaneous formation of the part and the convex part.

  Accordingly, the present invention, which has been devised to solve the above-mentioned problems, is a method for molding a plastic sheet comprising a sheet portion and a plurality of convex portions provided on one surface of the sheet portion, wherein a molten resin is used. A convex upper molding roll and a sheet base molding roll are arranged side by side with a gap facing each other so as to face the extrusion port of the T die that is flatly extruded, and the convex part is formed on the convex upper molding roll. An annular belt-shaped mold having a plurality of through-holes is wound, and the molten resin extruded from the T-die extrusion port is rotated by driving the convex upper molding roll and the sheet base molding. A projecting portion formed between the through hole of the belt-shaped mold and the convex upper molding roll, and guided between the roll and sandwiched between the belt-shaped mold and the sheet base molding roll. The convex portion is formed by the molten resin guided into the space, and at the same time, the sheet portion is formed by the molten resin in the sheet space formed between the portion other than the through hole of the belt-shaped mold and the sheet base forming roll. A method for forming a plastic sheet, characterized in that is molded.

  Further, according to the present invention, there is provided a through-hole in which the total volume of the plurality of through-holes perpendicular to the extrusion direction is a total of the same volume at any location with respect to the extrusion direction. A molding method characterized by using a sheet-like mold.

  Further, the present invention is a molding method characterized in that a belt-shaped mold having a through-gradient in the through hole is used.

  The present invention is characterized in that a plastic sheet having a horizontally long convex portion is formed by using a belt-shaped mold provided with a horizontally long through hole corresponding to the horizontally long convex portion obliquely with respect to the extrusion direction. Molding method.

  Further, the present invention is a molding apparatus for molding a plastic sheet comprising a sheet portion and a plurality of convex portions provided on one surface of the sheet portion, the convex device facing the extrusion port of the T die. An upper part forming roll and a sheet base forming roll are juxtaposed with a gap therebetween, and an annular belt-shaped mold having a plurality of through holes for forming the convex part is wound around the convex part upper forming roll. The belt-shaped mold and the sheet base molding roll are so fed that the molten resin extruded from the extrusion port of the T-die is guided and sandwiched between the belt-shaped mold and the sheet base molding roll. The convex portion is rotated by a drive of the convex upper forming roll, and the convex portion is formed by a molten resin introduced into a convex space formed by the through hole of the belt-shaped mold and the convex upper molding roll. At the same time as forming, the sheet portion is formed by molten resin in a sheet space formed between a portion other than the through hole of the belt-shaped mold and the sheet base forming roll. Molding equipment.

  In the present invention, the belt-shaped mold is turned in the direction of taking the plastic sheet, and the plurality of protrusions formed on one surface of the plastic sheet are released from the belt-shaped mold. A molding apparatus comprising a molding holding roll for the purpose.

  Further, the present invention is a molding apparatus characterized in that the annular belt-shaped mold is endless so that continuous production can be performed and a plastic sheet having a free length can be molded.

  Further, the present invention is a molding apparatus characterized in that cooling of the plastic sheet between the convex upper molding roll and the molding holding roll is performed by natural cooling or forced air cooling.

  Further, the present invention provides the molding apparatus characterized in that the plastic material of the belt-shaped mold is a plastic material having heat resistance that can withstand at least the melting temperature of the extruded resin.

  In the molding apparatus according to the present invention, the material of the belt-shaped mold is made of a metal softer than the rotating convex upper molding roll.

  The molten resin extruded flat from the T-die is sandwiched between a belt-shaped mold with a through-hole and a sheet base forming roll, and the plastic sheet surface and convex parts are simultaneously molded, so that the surface of the plastic sheet It is now possible to form a sheet provided with a large number of high protrusions.

  By molding with a belt-shaped mold with a through hole and a convex top molding mold, air can be completely vented by the through hole at the time of convex molding, so that many tall convex parts can be accurately molded. Became possible.

  A belt-shaped mold is provided with through-holes such that the space volume of the plurality of through-holes perpendicular to the extrusion direction is the same as the total volume at any location in the extrusion direction. Thus, the discharge amount of the extruder became constant, and stable extrusion molding became possible.

  By using a belt-shaped mold in which a through-gradient is attached to the through hole, the plurality of molded convex portions are easily released from the belt-shaped mold.

  For forming a plastic sheet with a horizontally long convex part, a horizontally long through hole corresponding to the horizontally long convex part is provided obliquely with respect to the extrusion direction in the belt mold so that the horizontally long convex part can be easily released from the belt shaped mold. Is done.

  The belt-shaped mold uses a plastic material with heat resistance that can withstand at least the melting temperature of the extruded resin, or a metal that is softer than the rotating convex upper forming roll, enabling a durable and inexpensive molding device. I made it.

  When plastic is used for the belt-shaped mold, the through-holes can be easily processed, and the degree of freedom in the design of convex products has increased.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic of the shaping | molding apparatus of this invention, (a) is a front view, (b) is a BB sectional drawing, and shows sectional drawing of the shape | molded plastic sheet. It is AA arrow sectional drawing of a shaping | molding apparatus, and the sectional side view of a molding machine is shown. The principal part enlarged view of a shaping | molding apparatus is shown. As a modification, it is explanatory drawing which shows the through-hole of the belt-shaped mold which shape | molds a special convex part, (a) is a top view showing one of the through-holes in the said belt-shaped mold, (b) It is CC line sectional drawing of a belt-shaped mold, (c) represents an example of the convex part of the plastic sheet which has a convex part from which height differs. It is explanatory drawing of the cyclic | annular belt-shaped mold with a through-hole, (a) is a top view of a belt-shaped mold, (b) represents the DD sectional view taken on the line of a belt-shaped mold. It is explanatory drawing of the plastic sheet comprised from a sheet | seat part and a convex part, (a) is a top view of a plastic sheet, (b) represents the EE sectional view taken on the line of a plastic sheet. It is explanatory drawing which shows the modification of this invention shaping | molding apparatus.

An example of the molding method and molding apparatus of the present invention for solving the above problems is shown in FIG. 1 to FIG. Moreover, the modification of this invention shaping | molding apparatus is shown in FIG.
As shown in FIG. 6, the plastic sheet 16 includes a sheet portion 16b and a convex portion 16a. The sheet portion 16b has a thickness of about 3 mm to 30 mm, and the convex portion 16a has a height of about 1 mm to 8 mm.
The plastic sheet 16 molded in accordance with the present invention is light and elastic, and becomes a floor plate that can withstand repeated use over a long period of time.

The molding apparatus is shown in FIGS. A T-die 11b is set in the plastic extruder 11a and the extruder, and the convex upper molding roll 12a and the sheet base molding roll 12b are arranged in parallel with a gap therebetween so as to face the extrusion port of the T-die 11b. Yes.
A molding auxiliary roll 12c is installed alongside the sheet base molding roll 12b below the convex upper molding roll 12a. The sheet base forming roll 12b is arranged on the upstream side of the convex upper forming roll 12a. A pair of forming holding rolls 13a and 13b are installed on the rear side. In addition, a pair of take-up rolls 14a and 14b are installed behind them.

  An annular belt-shaped mold 15 having a plurality of through holes 15a for forming the convex portion 16a is wound around the convex portion upper forming roll 12a and the molding holding roll 13a. The belt-shaped mold 15 is circulated and rotated in the Y direction by rotational driving in the X direction of the convex upper molding roll 12a and the molding holding roll 13b.

  As shown in FIG. 3, the belt-shaped mold 15 and the sheet base forming roll in which the resin kneaded at about 200 ° C. to about 300 ° C. in the extruder 11a is extruded in a flat shape from the T-die 11b and circulates and rotates. 12b, and the molten resin 11c is sandwiched between the belt-shaped mold 15 and the sheet base forming roll 12b and fed backward. Since the sheet base forming roll 12b is arranged on the upstream side of the convex upper forming roll 12a, the molten resin 11c is stored in the downstream portion from the top of the sheet base forming roll 12b.

  The convex portion 16a is molded by the molten resin 11c introduced into the convex space formed by the through hole 15a of the belt-shaped mold 15 and the convex portion upper molding roll 12a, and at the same time, the belt-shaped mold 15 is penetrated. The sheet portion 16b is formed by a molten resin in a sheet space formed between a portion other than the hole 15a and the sheet base forming roll 12b.

  As shown in FIG. 1, since the plastic sheet 16 immediately after molding is soft, the plastic sheet 16 is supported by the molding auxiliary roll 12c so as not to hang down and is sent to the pair of molding holding rolls 13a and 13b.

  The plastic sheet 16 is cooled between the convex upper molding roll 12a and the molding auxiliary roll 12c and the pair of molding holding rolls 13a and 13b. Cooling is preferably natural cooling or forced air cooling with a fan. Further, the distance at which the plastic sheet 16 is sufficiently cooled during this period varies depending on the material of the resin and the temperature, but for example, in the case of the plastic sheet 16 having a thickness of about 10 mm, about 1 to 3 m is desirable.

  After the plastic sheet 16 is cooled, it is taken up by a pair of take-up rolls 14a and 14b installed on the rear side, while the belt-shaped mold 15 is rotated in the Y direction by the rotation of the molding holding roll 13a in the X direction. The plurality of convex portions 16 a of the plastic sheet 16 are released from the belt-shaped mold 15.

  After the plastic sheet 16 is cooled and stabilized in shape, the plastic sheet 16 is taken up by a pair of take-up rolls 14a and 14b in the subsequent process, and then the product shown in FIG. 6 is obtained through a cutting process.

  Here, the convex part upper forming roll 12a, the forming holding roll 13a, and the take-up rolls 14a and 14b are drive rolls. The sheet base forming roll 12b, the forming auxiliary roll 12c, and the forming holding roll 13b are driven rolls. In addition to these rolls, there may be a roll necessary for supporting the plastic sheet 16 and a necessary roll for supporting the belt-shaped mold 15.

  It is desirable that the molten resin 11c extruded from the T die 11b is in an amount commensurate with the amount of resin of the product to be molded between the sheet base forming roll 12b and the belt-shaped mold 15.

  As shown in FIG. 5, a draft angle of 1 ° to 30 ° on one side is provided on the entire circumference of the through hole 15a so that the molded convex portion 16b can be easily removed from the through hole 15a of the belt-shaped mold 15. It has been.

As shown in (c) of FIG. 4, when the convex shape is not the same height in one convex portion 16 a, the penetration shown in (b) corresponding to the place where the height of the convex portion 16 a is low. The hole 15b may be a few small through holes 15b that perform an air bleeding function. When the convex shape is not the same height, a combination of a small through hole 15b and a large through hole 15a may be used. It is desirable that the small through-holes 15b have a number that can provide dimensional accuracy during air venting and molding.
The small through hole 15b is a hole into which the molten resin 11c does not enter and is preferably about 0.3 mm to 0.5 mm, although it varies depending on the resin used.

  As shown in FIG. 3, the molten resin 11c is guided to the through-hole 15a provided in the belt-shaped mold 15 and the convex upper molding roll 12a, and sandwiched between the sheet base molding roll 12b to be molded. The air entrained in the molding roll 12a and the resin 11c was released from the through-hole 15a, and the molten resin 11c could be filled to every corner, so that the convex portion 16a could be molded with high accuracy.

  For forming the horizontally long convex portion 16a of the plastic sheet 16 shown in FIG. 6, the horizontally long through hole 15a corresponding to the horizontally long convex portion 16a is formed in the extrusion direction so that the convex portion 16a can be easily released. It is desirable that the angle is 30 ° to 60 ° relative to the angle.

  As shown in FIG. 1, the convex part 16a is shape | molded with the molten resin 11c which digged into the belt-shaped mold 15, and it is sent to the shaping | molding auxiliary | assistant roll 12c, and between the shaping | molding holding | maintenance rolls 13a and 13b, the belt-shaped mold 15 After the convex portion 16a is cooled, the convex portion 16a is stabilized by cooling, and then taken up by the take-up rolls 14a and 14b.

  Next, by rotating the direction of the belt-shaped mold 15 in the direction of the arrow with Y through the molding holding roll 13a with respect to the take-up direction in which the plastic sheet 16 is marked with Z, the convex portion 16a is belt-shaped. It is released from the mold 15. In this way, the plastic sheet 16 having the large convex portions 16a shown in FIG. 1B is continuously formed and cut in the next step.

  The annular belt-shaped mold 15 is continuously rotated by driving the convex upper molding roll 12a and the molding holding roll 13a, thereby continuously molding the plastic sheet 16.

The shape and arrangement of the through-holes 15a of the belt-shaped mold 15 suitable for this forming method are such that the total of the space volumes of the through-holes 15a perpendicular to the extrusion direction takes any place with respect to the extrusion direction. However, it is desirable that the volumes be approximately the same. The extrusion amount of the extruder 11a becomes constant, and stable extrusion can be performed. Approximately the same volume is desirable up to ± 5%. The 5% fluctuation is absorbed by the stored molten resin 11c.
FIG. 5 is an example of the belt-shaped mold 15.

  In this molding method, the sheet width can be adjusted by adjusting the extrusion amount of the molten resin 11c extruded from the T die 11b, and continuous molding is possible. In addition, it is possible to produce products with free dimensions at the cutting position.

  The resin suitable for molding the plastic sheet 16 having the convex portion 16a of the present invention is not particularly limited, but polypropylene (PP), polyethylene (PE), a mixture of polypropylene and polyethylene, recycled materials thereof, and also polyvinyl alcohol. It can be applied to almost all thermoplastic resins such as (PVA), polyvinyl chloride (PVC), polyethylene terephthalate (PET), AS resin (AS), acrylic resin (PMMA), polyamide (PA), and polyacetal (POM).

  The annular belt-shaped mold 15 has an endless belt shape, and a suitable material is a plastic material having heat resistance that can withstand the melting temperature of the molten resin 11c, such as polyethylene terephthalate (PET), polycarbonate. (PC), polytetrafluoroethylene (PTFE), polyphenylene sulfide (PPS), polyarylate (PAR), polysulfone (PSF), polyethersulfone (PES), polyetherimide (PEI), polyamideimide (PAI) and Engineering plastics such as polyetheretherketone (PEEK) are suitable.

  As the metal material suitable for the belt-shaped mold 15, a metal material softer than the convex upper molding roll 12a is suitable so that the convex upper molding roll 12a is not damaged, and examples thereof include copper and nickel.

  A modification of the molding apparatus of the present invention is shown in FIG. The convex upper molding roll 12a and the sheet base molding roll 12b are arranged in parallel with a distance from each other so as to face directly below the extrusion port of the T die 11b, and the belt-shaped mold 15 is wound around the convex upper molding roll 12a. ing. The molten resin 11c is extruded directly under the T die 11b. Other contents are the same as those of the molding apparatus of the present invention. The molten resin 11c can be appropriately stored between the sheet base forming roll 12b and the belt-shaped mold 15 having the through holes 15a.

  It can be used in the product field where convex parts are provided on the surface of plastic such as civil engineering materials.

11a Extruder 11b T die 11c Molten resin 12a Convex part upper forming roll 12b Sheet base forming roll 12c Molding auxiliary roll 13a Molding holding roll 13b Molding holding roll 14a Take-up roll 14b Take-off roll 15 Belt-shaped mold 15a Through-hole 15b Small through-hole 16 Plastic sheet 16a Convex part 16b Sheet part

Claims (10)

A method of molding a plastic sheet comprising a sheet portion and a plurality of convex portions provided on one surface of the sheet portion,
Facing the extrusion port of the T-die that extrudes the molten resin flatly, the convex upper molding roll and the sheet base molding roll are juxtaposed with a gap between them,
An annular belt-shaped mold having a plurality of through holes for forming the convex portion is wound around the convex portion upper forming roll,
The molten resin extruded from the extrusion port of the T-die is guided between the belt-shaped mold and the sheet base molding roll rotating by driving the convex upper molding roll, and the belt-shaped mold and the sheet Hold it between the base forming rolls and send it out.
At the same time as forming the convex portion by the molten resin introduced into the convex space formed by the through hole of the belt-shaped mold and the convex portion upper molding roll,
A method for molding a plastic sheet, characterized in that the sheet portion is molded by a molten resin in a sheet space formed between a portion other than the through hole of the belt-shaped mold and the sheet base molding roll. 2. The molding method according to claim 1, wherein the total volume of the plurality of through-holes perpendicular to the extrusion direction is a total of ± 5% at any location with respect to the extrusion direction. A molding method characterized by using a sheet-like mold having a through-hole.   3. The molding method according to claim 1, wherein a belt-shaped mold having a draft is used for the through hole.   In the shaping | molding method of Claim 1 or 2, in shaping | molding of the plastic sheet which has a horizontally long convex part, the horizontally long through-hole corresponding to a horizontally long convex part was provided in the belt-shaped mold diagonally with respect to the extrusion direction. A molding method characterized by using a material. A molding apparatus for molding a plastic sheet comprising a sheet portion and a plurality of convex portions provided on one surface of the sheet portion,
Opposite the extrusion port of the T-die, the convex upper molding roll and the sheet base molding roll are juxtaposed with a gap,
An annular belt-shaped mold having a plurality of through holes for forming the convex portion is wound around the convex upper forming roll,
The belt-shaped mold and the sheet base molding roll are used so that the molten resin extruded from the extrusion port of the T-die is guided and sandwiched between the belt-shaped mold and the sheet base molding roll. Rotated by driving the convex upper forming roll,
At the same time as forming the convex portion by the molten resin introduced into the convex space formed by the through hole of the belt-shaped mold and the convex portion upper molding roll,
An apparatus for molding a plastic sheet, wherein the sheet portion is molded by a molten resin in a sheet space formed between a portion other than the through hole of the belt-shaped mold and the sheet base molding roll.   6. The molding apparatus according to claim 5, wherein a plurality of convex portions formed on one surface of the plastic sheet are formed by turning the belt-shaped mold with respect to the take-up direction of the plastic sheet. A molding apparatus comprising a molding holding roll for releasing from the mold.   7. The molding apparatus according to claim 5, wherein the annular belt-shaped mold is endless.   8. The molding apparatus according to claim 6, wherein the plastic sheet is cooled by natural cooling or forced air cooling from the upper convex roll to the molding holding roll.   The molding apparatus according to claim 5, wherein the plastic material of the belt-shaped mold is a plastic material having heat resistance that can withstand at least the melting temperature of the resin to be extruded. apparatus.   9. The molding apparatus according to claim 5, wherein the material of the belt-shaped mold is made of a metal softer than a rotating convex upper molding roll.

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