JP4070664B2 - Beautiful end face seal of plastic hollow sheet - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technology for neatly sealing and molding an end surface portion of a corrugated plastic hollow sheet.
[0002]
[Prior art]
Recently, in place of a conventional paper cardboard box, a plurality of partition walls 3 are integrally formed at equal intervals between a front wall 2 and a back wall 2 'corresponding to a cardboard liner as shown in FIG. A resin cardboard box formed of a case blank made of a synthetic resin plate 1 has been frequently used. It has a through-opening groove 4 that is open at both end surfaces formed by the partition wall 3 and is integrally formed with a synthetic resin such as polypropylene or polycarbonate by extrusion molding. These resin corrugated cardboard boxes have the advantages of being stronger than paper and can be used repeatedly as a pass-through box, etc., are easy to clean, etc., and can be used repeatedly for a long time. Therefore, recently, it has been widely applied to various panels, pallet stacking boards, signboards, and the like as materials for replacing plywood as well as box materials. However, since the plastic hollow sheet 1 is punched to an appropriate size depending on the product, the plastic hollow sheet 1 has a large number of opening grooves 4 whose end surfaces are open in the longitudinal direction of the partition wall as in the case of conventional cardboard. Therefore, there is a defect that foreign matters such as insects and dust enter the opening groove 4 in the repeated use process. Therefore, an end surface treatment for sealing both ends of the opening groove has been conventionally performed in order to prevent intrusion of foreign matter.
[0003]
The present applicant has previously filed a patent application by presenting Patent Document 1 “Hollow Synthetic Resin Plate and End Surface Treatment Method and Apparatus”. This invention has a uniform surface shape of the heat-welded part, the finished dimensions of the product are accurate and stable, less warp, less likely to cause pinholes, and can be sealed uniformly, and no safety edge is generated -Obtaining a hollow synthetic resin plate having an end surface treatment part excellent in hygiene and aesthetics, a hollow synthetic resin plate end surface treatment method and apparatus for obtaining the hollow synthetic resin plate, and a case blank in one step The purpose of the present invention is to provide a case blank end face processing apparatus capable of end face processing. The hollow synthetic resin plate end face processing apparatus includes a receiving plate for receiving the hollow synthetic resin plate, a gauge plate for positioning the end face, and an end face portion. A pair of molding plates having a molding die surface that is thermoformed from above and below, and a presser plate, and arranged on the partition wall of the hollow synthetic resin plate at a right angle from the side to the opening end surface. Department molding hot plate is displaceably arranged abut. The processing is as shown in FIG. 6. In A, the hollow synthetic resin plate is conveyed on the receiving plate by an appropriate conveying means, and the end surface where the opening groove is opened is lowered to the gauge position. The end face is positioned by touching the gauge plate. Next, when the presser plate is lowered, the hollow synthetic resin plate is pressed and held at that position, and the gauge plate is raised. In this state, the cylinder device is operated to displace the molding hot plate heated to a predetermined temperature by the heater in advance to the hollow synthetic resin plate side. By displacing a predetermined amount while melting from the part, the partition wall is melted in a substantially triangular shape at the inclined side of the triangular prismatic hot plate, and the front wall and the back wall are brought into contact with the inclined side of the molded hot plate. The wall and back wall tips are also softened (B in FIG. 6). Thereafter, the molded hot plate returns and retracts, and at the same time, the molded plate moves from above and below to sandwich the hollow synthetic resin plate and press-mold the molten part. At that time, because the partition wall is melted in a triangular shape, the front wall and the back wall are easily deformed, and the front wall edge and the back wall edge are joined at the intermediate thickness portion of the hollow synthetic resin plate. There is little occurrence of wrinkles or the like on the end surface processing portion surface, and a smoothly arced end surface processing shape as shown in FIG. 7B can be obtained. However, in the case of the end surface processing by this method, a step or a molten resin remains as burrs on the sheet end surface as shown in FIG. When used as a box, this is not a problem at all. However, when it is used as a material that is exposed to the human eye, such as a signboard or an exhibition panel, it is beautiful to improve the product value. Will be required.
[0004]
[Patent Document 1]
Published on June 13, 2000, JP-A 2000-158530, “Hollow Synthetic Resin Plate and End Face Treatment Method and Apparatus”. [0005] to [0013], FIG. 1 and FIG.
[Patent Document 2]
Publication of Japanese Patent Publication No. 48-20036 “Method and apparatus for sealing the edge of a hollow synthetic resin plate” on June 18, 1973.
[0005]
[Problems to be solved by the invention]
It is an object of the present invention to provide a beautiful end face sealing method for a plastic hollow sheet that can be neatly sealed without leaving any burrs on the end face of the plastic hollow sheet and has a high processing speed, and a processing apparatus and a beautiful end face thereof. The object is to provide a sealed plastic hollow sheet.
[0006]
[Means for Solving the Problems]
The method of beautifully sealing and molding the end face of the plastic hollow sheet of the present invention is such that the groove width is formed wider than the thickness of the plastic hollow sheet on the front side, and the width gradually increases toward the rear stage. Using a heating block formed in a shape that becomes narrow near the thickness and the bottom of the groove gradually becomes shallower toward the rear stage, the end face part of the plastic hollow sheet is attached to the groove part of the heated block. Insert and move the block and the sheet relatively in parallel from the front side to the back side to make the end face part in a semi-molten state in the front stage and absorb the excess resin in the hollow part corresponding to the reduction of the groove space. after the said end face and compressed formed downstream of the groove shape while, cleanly be sealed forming the end faces of the hollow plastic sheet by cooling and solidifying with cooling block .
Further, the beautiful end face sealing device for a plastic hollow sheet according to the present invention is formed so that the width dimension is wider than the thickness of the plastic hollow sheet on the front side, and the width gradually becomes the thickness of the plastic hollow sheet toward the rear side. A heating block formed in a groove shape that becomes narrower in the vicinity and whose bottom gradually becomes shallower toward the rear stage, means for heating the heating block to a predetermined temperature, a cooling block having a groove formed thereon, The groove portion of the block in a state of being heated by the moving means, comprising a means for moving the plastic hollow sheet, which is a processed product, in parallel with the heating block surface on which the groove is formed Insert the end face part of the plastic hollow sheet into the block and slide the block and the sheet relatively from the front side to the rear stage side. After the said end face and compressed form to the subsequent groove shape corresponding to the reduction of the groove chamber with a semi-molten state at, and so as to cool and solidify in the groove of the cooling block.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
As described above, as a method for sealing the end surface of the plastic hollow sheet, as described above, the hot plate, which is a hot trowel, is pressed against the released end surface portion to dissolve the sheet resin into a V shape. At the same time, the two molded plates move from the top and bottom to sandwich the hollow synthetic resin plate and press mold the melted part. In view of the fact that it remains, the present invention contemplates that the resin in the vicinity of the end is softened and semi-molten and molded by a mold. By the way, the processing method for forming the groove shape by passing the groove portion in the softened and semi-molten state of the resin in the vicinity of the end portion and sealing the open end surface is a technique previously proposed by the present applicant (Patent Document 2). is there. In this invention, a hollow synthetic resin plate cut into a predetermined shape is held and moved between drive belts that occupy up and down and circulate, and at the same time, occupy both sides of the drive belt and synchronize with this drive belt. The cutting edge of the hollow synthetic resin plate is brought into contact with the heated steel belt to be circulated, the cutting edge is heated and softened, and then the heat-softened resin plate is forcibly bent inward through the guide groove. The opening portion is sealed. The bottom of the groove gradually becomes shallow as indicated by an inclined bottom in FIG. 5A, and a curved depression is formed in the cross section. As a result, the end face is sealed with the softened resin material, but the end of the sheet is formed slightly thicker as shown in FIG. 5B. However, this structure has a disadvantage that the end portion formed slightly thicker hits another member and is easily chipped and is structurally fragile. In addition, since the sheet heated from the side and softened at the edge is merely passed through a simple groove, the finished state of the end face is not clean.
[0008]
Therefore, in the present invention, not only the end surface of the plastic hollow sheet but also the vicinity of the plastic sheet is heated and softened, the sheet is compressed both in the thickness direction and in the width direction, and the surplus resin is absorbed in the hollow area of the sheet, The surface is finished to a desired shape, but a series of operations of heating, compression, molding, and cooling solidification are all performed in the groove. First, the groove width of the groove of the heating block is formed wider than the thickness of the plastic hollow sheet in the former stage, and the width becomes narrower near the thickness of the plastic hollow sheet in the middle stage and the bottom of the groove It is formed in an arc shape and the depth gradually decreases from the middle stage to the rear stage. Using this heating block, the end face part of the plastic hollow sheet is inserted into the groove part of the heated block, and the front stage side By sliding in the groove from the first stage to the rear stage, the end face part is made into a semi-molten state in the first stage, and the end face part is compression-molded into the second stage groove shape corresponding to the reduction of the groove space, and then cooled and solidified. Clean the end face of the plastic hollow sheet. In the present invention, the block and the sheet need only be relatively displaced, and any of the moving means for implementation may be the fixed side or the moving side.
[0009]
[Example 1]
The present invention can be applied to a plastic hollow sheet having a thickness of 2 mm to 14 mm. Here, a system for performing end face sealing of a plastic hollow sheet having a thickness of 2.5 mm will be described with reference to FIGS. 1 to 3. . FIG. 1 shows a heating block 5 in which a special groove structure is formed as a main part of the present invention. In FIG. 1, A is a cross section cut out in the depth direction at the center of the groove so that the depth shape of the groove 51 can be seen. Fig. B is a plan view of the surface on which the groove 51 is formed, C is an enlarged view of the depth dimension inflection part circled in A of the figure, and D is a width dimension change circled in B of the figure. It is an enlarged view of a music part. A and B are the pre-stage side that accepts a plastic hollow sheet whose left side is a workpiece. The sheet is received from the right side of the groove 51 and passes to the left side. The material is preferably a metal material having excellent thermal conductivity (aluminum in this embodiment), and at least the surface of the groove is preferably subjected to heat-resistant Teflon (registered trademark of DuPont). The heating block 5 has a total length of L10 + L11 + L12 (200 mm in this embodiment), and the groove shape is processed with R4 (3 mm in this embodiment) in the width direction at the front side end so that a hollow sheet can be easily received. Up to L10 (90 mm in this embodiment), the depth dimension L1 (6 mm in this embodiment) and the width dimension L5 (4. In this embodiment) are shown in FIG. 5 mm) followed by a constant rectangular cross section. Since this embodiment is for processing a hollow sheet having a thickness of 2.5 mm, the front and back walls of the sheet are not in close contact with the groove side but in a loosely sandwiched state, and preheat the vicinity of the sheet end surface. Responsible for the softening process. At the front stage L10, the shape of the groove 5 is tapered in the depth direction, and in the next section of L11 (95 mm in this embodiment), the bottom shape is processed into the inner side R6 (1.5 mm in this embodiment). And the depth dimension gradually decreases from L2 (5 mm in this embodiment) to L8 (1.7 mm in this embodiment). As can be seen from the enlarged view of this inflection portion shown in FIG. 1C, in this inflection portion, the depth dimension changes rapidly from L1 (6 mm in this embodiment) to L2 (5 mm in this embodiment). In the meantime, it is processed into R1 (10 mm in this embodiment) from the outside. The shape of the groove 5 in the width direction is the previous stage L10, and the width dimension suddenly changes from L5 (4.5 mm in this embodiment) to L6 (3 mm in this embodiment), and then to the next L11 (95 mm in this embodiment). ) And L12 (15 mm in this embodiment) remain the width of L6. At the inflection point at the front stage L10, as shown in enlarged view in FIG. 1D, the front half is R2 (2.25 mm in this embodiment) and the second half is R3 (10 mm in this embodiment). Has been processed. In the latter L12 section, the depth dimension is constant at L8 (1.7 mm in this embodiment). The groove edge portion is chamfered on the outer side R5 (0.4 mm in this embodiment) over the entire longitudinal direction.
[0010]
In the form of the heating block 5 that is formed as described above and heated, the plastic hollow sheet 1 is moved in parallel from the front side to the rear side with the opening end face of the plastic hollow sheet 1 facing the bottom surface. The heating block 5 incorporates a heater (not shown) (cylindrical heater in this embodiment), and the temperature is selected according to the material of the plastic hollow sheet, but in the case of polypropylene or polycarbonate, it is 200 ° C. to 240 ° C. It is preferable to maintain the degree. It is necessary to melt and soften the resin in the end surface treatment part in the process of passing through the section up to the front stage L10, and the moving speed is about 4.0 m / min. In this section, the side surface and the bottom of the groove sheet are not in contact with each other through a slight gap, but are heated by radiant heat and hot air, and are softened to reach the L10 point. Here, the bottom of the groove shape gradually becomes shallower and the width is narrowed from L5 to L6 at a stroke. First, the sheet end face comes into contact with the bottom and undergoes pressure deformation. At this time, the width dimension L6 is 3 mm in this embodiment, and the thickness of the hollow sheet of the workpiece is 2.5 mm. Therefore, this dimension is larger than the thickness of the original hollow sheet. Therefore, the softened excess plastic compressed at the bottom is initially absorbed mainly in the width direction. As the process proceeds further, the plastic in contact with the groove surface is melted and compressed by the bottom part that becomes shallower on the tapered surface, but at this stage, the excess plastic has no margin in the width direction and is hollow. Will be absorbed by the part. That is, the surplus plastic in a molten state is pushed into the hollow portion while receiving a pressure from the groove wall surface and being regulated in shape. Since this state continues to the end portion on the rear side of the heating block, the sheet end surface after passing through the heating block is formed into a U-shaped groove cross-sectional shape that is slightly thicker than the thickness dimension by coating the opening. .
[0011]
In this embodiment, the final shape of the sheet end face is formed and solidified by passing the groove 61 of the cooling block 6 following the heating block 5. The cooling block 6 has a form as shown in FIG. 3 and is made of a metal material having high thermal conductivity (aluminum in this embodiment), and the surface of the groove is Teflon (registered trademark of DuPont) to prevent thermal welding. ) It is desirable that it is processed. In the figure, A is a cross-sectional view cut in the depth direction at the center of the groove so that the depth shape of the groove 61 can be understood, B is a plan view of the surface in which the groove 61 is drilled, and C is a state in which the groove is directed downward And D is a sectional view taken along the line dd in FIG. The cooling block 6 is arranged in a tandem configuration with a slight gap from the previous heating block 5 and the same position of the block surface with respect to the hollow sheet 1 that is a workpiece. The hollow sheet 1 is moved in parallel to the block surface, and is carried in from the left side of the block 6 in the figure and exits to the right side. The cooling block 6 has a total length L31 + L32 (100 mm in this embodiment), and the shape of the groove 61 is L35 (6 mm in this embodiment) and the heating block 5 at the front end in the depth direction so that the hollow sheet 1 can be easily received. Is processed deeper than the depth dimension L8 (1.7 mm in this embodiment) of the end shape formed in (1). Then, up to L31 (50 mm in this embodiment) in the previous stage, as shown in a sectional view in FIG. In the embodiment, a constant taper plane continues up to 3.3 mm), and the section of L32 at the subsequent stage from the position of L31 remains constant at L36. However, in order to prevent discontinuity at the L31 position, the vicinity of the L31 position is subjected to a curved surface processing of R10 (20 mm in this embodiment) from the outside. Further, the groove shape in the width direction is shown in FIG. 3B, and the width direction shape of the groove 61 is L37 in the width direction of the front side end portion so that the hollow sheet 1 can be easily received (6. 3 mm) and the width L7 of the end shape formed by the heating block 5 (3 mm in this embodiment), and after that, the width dimension is L38 for a distance L30 (40 mm in this embodiment) from the left end. Both sides are tapered and narrow. Then, after the position of the distance L35, processing is performed to a constant width with the width dimension being L38. Also, the bottom shape is a flat surface between the front L31, but the rear L31 is R11 (0.6 mm in this embodiment) U-shaped from the inside, and the side surface until it becomes a flat surface of the width L38 is It is processed into a curved surface of R12 (4.37 mm in this embodiment) from the inside. Therefore, the shape of the groove cross section is rectangular up to L31 in the front stage, and the L32 section in the rear stage is a depth dimension L36 (3.3 mm in this embodiment) as shown as a dd cross section in FIG. And a U-shaped cross section having a width L38 (2.3 mm in this embodiment). Further, the groove edge portion is chamfered on the outer side R13 (0.3 mm in this embodiment) over the entire longitudinal direction.
[0012]
The end surface of the hollow plastic sheet 1 shaped and processed in the state of being heated and softened by the groove of the heating block 5 faces the bottom surface of the groove 61 of the cooling block 6 in the groove of the cooling block 6 formed as described above. According to the configuration, the translation is performed from the front stage side to the rear stage side (left side to right side in FIG. 3). Although the cooling means is not shown, a flow path is provided inside the block to flow cooling water. Cooling water only needs to be circulated at room temperature. The end surface of the hollow sheet in the softened and melted state is initially brought into the groove 61 in a non-contact state, but the groove 61 becomes shallower and narrower in both the depth direction and the width direction, so that it comes into contact with the groove wall surface and is cooled. At the same time, the shape is compressed and formed into a U-shaped cross section shown in FIG. Excess resin is absorbed in the hollow portion, and when passing through the cooling block 6, the resin is cooled and solidified, and the cross-sectional shape is formed and solidified.
In addition, when the end face treatment of the hollow sheet is only for sealing the opening groove 4, it is only necessary to process the side perpendicular to the longitudinal direction of the partition wall 3, but the partition wall 3 is used when used as an exhibition panel or a decorative board. This beautiful end face treatment is also applied to the side in the direction parallel to. Incidentally, FIG. 4 shows the finished form of the plastic hollow sheet that has been subjected to the end face sealing treatment by the apparatus of this embodiment. Since the molten resin is compressed by the groove of the cooling block having a U-shaped cross section with a bottom width narrower than the sheet thickness, the straight end surface portion is pushed into the hollow portion near the end surface and the end surface is formed and solidified into a thin U shape. The In the finished form, as shown in FIG. 5B, the end portion of the sheet is not formed to be slightly thick, and the end surface processed portion becomes a thin and beautiful parabolic shape like the portion surrounded by a wavy circle in FIG. Therefore, it does not collide or get caught by other members, and mechanical strength is provided by the presence of the melted and solidified resin in the hollow part.
[0013]
【The invention's effect】
The method of beautifully sealing and molding the end face of the plastic hollow sheet of the present invention is such that the groove width is formed wider than the thickness of the plastic hollow sheet on the front side, and the width gradually increases toward the rear stage. Using a heating block formed in a shape that becomes narrow near the thickness and the bottom of the groove gradually becomes shallower toward the rear stage, the end face part of the plastic hollow sheet is attached to the groove part of the heated block. Insert and move the block and the sheet relatively in parallel from the front side to the back side to make the end face part in a semi-molten state in the front stage and absorb the excess resin in the hollow part corresponding to the reduction of the groove space. However, since the end face portion is compressed and formed into a groove shape in the subsequent stage and then cooled and solidified, the end face portion of the plastic hollow sheet is simply passed through the groove. Together with clean can sealing treatment the groove cross-sectional shape does not remain, it can be realized a beautiful end face seal method machining speed is fast hollow plastic sheet.
[0014]
Further, the beautiful end face sealing device for a plastic hollow sheet according to the present invention is formed so that the width dimension is wider than the thickness of the plastic hollow sheet on the front side, and the width gradually becomes the thickness of the plastic hollow sheet toward the rear side. Holds a heating block formed in a groove shape that becomes narrower in the vicinity and gradually becomes shallower toward the rear, a means for heating the heating block to a predetermined temperature, and a plastic hollow sheet that is a workpiece In this state, the end face part of the plastic hollow sheet is inserted into the groove part of the block heated by the moving means. By simply moving the block and the seat relatively from the front side to the rear side, there is no burrs. It is sealing treatment, it is possible to provide a beautiful end face seal device of the machining speed is high hollow plastic sheet.
Further, a cooling block having a groove whose front side is formed wider than the end surface of the hollow plastic sheet formed by the groove of the heating block, gradually decreases in width toward the rear side, and whose bottom is formed in an arc shape. The beautiful end face sealing device for a plastic hollow sheet according to the present invention disposed downstream of the heating block receives the sheet end face formed in a groove shape in a semi-molten state by the heating block into the groove of the cooling block by a moving means. In response to the reduction of the groove space, the end face portion is compressed and formed into a subsequent groove shape and is cooled and solidified, so that the end face processed hollow sheet has a fine and clean parabolic shape. Therefore, it does not collide or get caught by other members, and mechanical strength is provided by the presence of the melted and solidified resin in the hollow part.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a groove structure of a heating block according to the present invention.
FIG. 2 is a diagram illustrating a groove cross-sectional shape of a heating block according to the present invention.
FIG. 3 is a diagram illustrating a groove structure of a cooling block according to the present invention.
FIG. 4 is a view showing a finished form of an end face sealing process performed by an apparatus according to an embodiment of the present invention.
FIG. 5 is a view for explaining a prior art for forming an end surface portion of a plastic hollow sheet into a groove shape.
FIG. 6 is a view for explaining a conventional technique for sealing an end surface portion of a plastic hollow sheet.
FIG. 7 is a view for explaining the shape of the end face portion of the plastic hollow sheet and the seal form according to the prior art.
[Explanation of symbols]
1 Plastic hollow body sheet 5 Heating block 2 Front wall 51 Heating block groove 2 'Back wall 6 Cooling block 3 Partition wall 61 Cooling block groove 4 Opening groove

Claims (5)

The groove width is formed wider than the thickness of the plastic hollow sheet in the pre- stage side preheating region , and the width gradually decreases toward the thickness of the plastic hollow sheet toward the rear stage, and the bottom of the groove is formed in the rear stage. Using a heating block formed in a shape that gradually becomes shallower toward the surface, insert an end surface portion of the plastic hollow sheet into the groove portion of the heated block, and relatively move the block and the sheet from the front side. After translating to the rear stage side, the end face part is made into a semi-molten state in the previous stage and the end face part is compressed into the groove shape of the rear stage while absorbing the excess resin in the hollow part corresponding to the reduction of the groove space, A method of cleanly molding the end face of a plastic hollow sheet by cooling and solidifying it using a cooling block . In the pre-stage preheating region , the width dimension is formed wider than the thickness of the plastic hollow sheet, and gradually toward the rear stage, the width becomes narrower near the thickness of the plastic hollow sheet, and the bottom part toward the rear stage. While holding the heating block formed in the groove shape gradually becoming shallower, the means for heating the heating block to a predetermined temperature, the cooling block formed with the groove , and the plastic hollow sheet as the workpiece Means for moving parallel to the heating block surface on which the groove is formed, and inserting the end surface portion of the plastic hollow sheet into the groove portion of the block heated by the moving means. The sheet is relatively slid from the front side to the rear side, and the end surface portion is made into a semi-molten state in the front stage and the groove space is reduced. After the said end face and compressed formed downstream of groove shape, beautiful face seal device of the plastic hollow sheet, characterized in that to cool and solidify in the groove of the cooling block.   The beautiful end face sealing device for a plastic hollow sheet according to claim 2, wherein the cross-sectional shape of the rear side groove of the heating block is U-shaped. Front side of the cooling block is formed wider than the hollow plastic sheet end surface formed by the grooves of the heating block, and gradually with its width decreases toward the rear stage, a groove whose bottom is formed in a circular arc shape, The sheet end surface disposed in the rear stage of the heating block, which is formed in a groove shape in a semi-molten state by the heating block, is received in the groove of the cooling block by relative movement means, and the groove space is reduced. 4. The beautiful end face sealing device for a plastic hollow sheet according to claim 2, wherein the end face portion is compressed and formed into a groove shape in the latter stage and cooled and solidified.   The beautiful end face sealing device for a plastic hollow sheet according to claim 4, wherein the cross-sectional shape of the rear side groove of the cooling block is U-shaped.

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