JP2007030251A - Manufacturing method of synthetic resin sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoplastic synthetic resin sheet wherein two kinds of synthetic resins comprising a transparent part and a devitrified part are alternately arranged in a vertically striped state. <P>SOLUTION: This manufacturing apparatus of the synthetic resin sheet is equipped with a feed block 1, which has two round holes 11a and 11b formed in parallel to each other so as to be partially superposed one upon another, the slit 14 downward opened from the superposed part of the two round holes 11a and 11b and two manifolds 13a and 13b respectively formed on the lateral sides of the respective round holes 11a and 11b and press-fitting a molten thermoplastic synthetic resin, and a laterally poly-branched valve 10 composed of two rod materials 2a and 2b different in diameter inserted in two round holes 11a and 11b, alternately changed to large and small diameter parts 21 and 22 in a longitudinal direction and characterized in that the large and small diameter parts 21 and 22 of them are meshed mutually. The press-fitted two kinds of the molten thermoplastic synthetic resins are discharged from the slit 14 of the feed block 1 in a sheetlike state by being alternately joined and arranged in a vertically-striped state to be thinly widened by a T-die 3 and cooled by a cooling roll to be molded into a sheet. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a synthetic resin sheet manufacturing apparatus for forming two types of synthetic resins, which are formed of a transparent portion and a devitrified portion or a colored portion, in a striped pattern in the vertical direction.

  Synthetic resin containers such as PET bottles have the property of permeating low-molecular gases such as oxygen and carbon dioxide, and also have the property of adsorbing low-molecular organic compounds. Therefore, when carbonated beverages are added, carbon dioxide permeates from the inside or low molecular organic compounds are adsorbed, so that a silicon oxide film is deposited on the inner surface of the synthetic resin container, or high frequency plasma CVD is used. A carbon film is formed to improve gas barrier properties.

  However, when such synthetic resin containers with improved gas barrier properties are discarded and recycled, inorganic substances such as silicon oxide and carbon become impurities, become translucent or opaque and devitrify, so their use is limited. Is done.

  On the other hand, a thin synthetic resin sheet made of thermoplastic synthetic resin as a raw material is vacuum-molded or blow-molded, and the body part and the lid part are integrally connected via a foldable connecting part, Thin-walled synthetic resin containers having recesses for storing articles and flanges at the periphery are widely used in various fields as packaging containers for storing foods such as eggs, fruits, vegetables, and prepared dishes.

  In such a thin synthetic resin container, the lid portion must be transparent in order to visually observe the packaged item, but the body portion may be practically used even if it is opaque, translucent or colored. It is.

  Thus, the synthetic resin sheet for shape | molding the cover part and body part of a thin synthetic resin container with a different synthetic resin is proposed by the following patent document.

As shown in FIG. 8, this synthetic resin sheet includes a transparent synthetic resin sheet 61 having a width necessary for molding the lid portion and an opaque synthetic resin sheet having a width necessary for molding the body portion. 62 are arranged side by side, and a transparent synthetic resin sheet 63 is laminated on the entire surface of one side of both sheets 61 and 62. Then, the container is processed by vacuum molding or blow molding so that the boundary between the transparent portion and the opaque portion of the sheet 6 coincides with the foldable connecting portion of the container.
Japanese Utility Model Publication No. 3-43132

  Such a conventional synthetic resin sheet 6 requires a step of obtaining a transparent synthetic resin sheet 61, a step of obtaining an opaque synthetic resin sheet 62, and a step of laminating the transparent synthetic resin sheet 63. However, it was difficult to put it to practical use.

  In order to use a recycled sheet devitrified by recycling as a body part and a transparent sheet as a lid part and to utilize it as a thin synthetic resin container, as shown in FIG. 7, as a thermoplastic synthetic resin sheet, Obtain a vertically striped sheet in which transparent portions A and devitrified portions B are alternately arranged, align transparent portion A with the lid portion as shown by dotted line C, and align devitrified portion B with the body portion. It is desirable to mold as follows. However, a technique for molding a vertically striped synthetic resin sheet in which transparent sheets and devitrified sheets are alternately arranged in the width direction has not yet been generalized.

  Therefore, the present invention is considered for the purpose of obtaining a thermoplastic synthetic resin sheet in which two kinds of synthetic resins comprising a transparent portion A and a devitrified portion B as shown in FIG. 7 are alternately arranged in a vertical stripe shape. It is what was done.

  The synthetic resin sheet manufacturing apparatus according to the present invention includes two round holes that are opened in parallel so as to partially overlap, a slit that is opened downward from the overlapping portion of the two round holes, and the side of each of the round holes. Feed block having two manifolds that are respectively pressed into the melted thermoplastic molten synthetic resin, and inserted into the two round holes, and the diameter is alternated between a large diameter portion and a small diameter portion in the longitudinal direction. And two large-diameter branch valves made of two different-diameter rods with one large-diameter portion meshing with the other small-diameter portion. In a state of being alternately joined and arranged in a vertical stripe shape, the sheet is discharged in a plate shape from the slit of the feed block, thinned and widened by a T die, cooled by a cooling roll, and formed into a sheet.

  According to the synthetic resin sheet manufacturing apparatus of the present invention, by rotating the different-diameter bar, the ratio in the width direction of the two types of synthetic resin sheets arranged alternately in stripes can be changed. Is possible.

  Moreover, it is easy to change the width and number of the two types of synthetic resin sheets that are arranged by alternately joining stripes in the width direction by exchanging rods having different diameters.

  The manufactured synthetic resin sheet has high adhesive strength despite the small bonding width between two adjacent sheets, and processed into a thin-walled container by vacuum molding or blow molding in the same way as ordinary synthetic resin sheets. can do.

  A conventional apparatus can be used as it is for peripheral devices such as a T-die and a cooling roll for widening, and the synthetic resin sheet manufacturing apparatus of the present invention can be configured.

  As shown in FIG. 1, an apparatus for producing a striped synthetic resin sheet according to the present invention includes two extruders (not shown) that heat and melt a transparent synthetic resin and a devitrified synthetic resin, respectively. ), Two sub-manifolds 13a and 13b to which transparent molten synthetic resin and devitrified molten synthetic resin are respectively supplied from two extruders, and supplied transparent molten synthetic resin and devitrified molten synthetic resin Are arranged in vertical stripes alternately, and feed blocks 1 having two multi-diameter valves 10 made of different diameter rods 2a and 2b that discharge in a flat plate form from slits 14 and flat stripes arranged in vertical stripes. The melted synthetic resin discharged in a thin shape is thinly widened, and the cooling roll 4 is formed into a sheet while cooling the thinly widened vertical stripe-shaped molten synthetic resin. Reference numeral 5 shown in the drawing is a metal fitting for connecting the feed block 1 and the T die 3.

  Two flow distribution valves 16a disposed on the downstream side of the multi-branch valve 10 in the width direction are provided in order to provide slipperiness when the finished synthetic resin sheet is processed into a thin wall container by vacuum molding or blow molding. , 16b and two sub-manifolds 15a, 15b, and supplies raw materials for forming a surface layer containing a lubricant on both sides of the molten synthetic resin discharged in a flat plate shape.

  As shown in the side view of FIG. 2, the cross-sectional view of FIG. 3 and the perspective view of FIG. 5, the multi-branch valve 10 in the width direction has two round holes 11a and 11b opened in parallel so that a part thereof is overlapped. A slit 14 is opened downward from the overlapped portion, and the feed block 1 having holes 12a and 12b communicating with the sub-manifolds 13a and 13b on the sides of the round holes 11a and 11b and the adjacent round holes 11a and 11b are inserted. And two different-diameter bars 2a and 2b whose diameters change alternately in the longitudinal direction.

  As shown in the perspective view of FIG. 4, the two different-diameter rods 2a and 2b arranged in parallel alternately have a large-diameter portion 21 having a large diameter and a small-diameter portion 22 having a small diameter in the longitudinal direction. The diameter of the large diameter portion 21 coincides with the inner diameter of the round holes 11a and 11b of the feed block 1, and the difference in radius between the large diameter portion 21 and the small diameter portion 22 is equal to the adjacent round hole 11a, 11b coincides with the overlapping length.

  And when inserting the two different diameter rods 2a and 2b in the two round holes 11a and 11b of the feed block 1, as shown in the perspective view of FIG. Insert it in the engaged state.

  The large-diameter portion 21 and the small-diameter portion 22 of the two different-diameter bar members 2a and 2b are shown in FIG. It consists of a wide part 21a and a narrow part 21b, and the small-diameter part 22 also consists of a wide part 22a and a narrow part 22b whose width changes continuously. 21 is inserted into the adjacent round holes 11a and 11b of the feed block 1 so as to mesh with the small-diameter portion 22 of the other different-diameter bar 2b. The sum of the width of the large-diameter portion 21 of one pitch and the width of the small-diameter portion 22 is set equal over the entire circumference.

  The two different-diameter bar members 2a and 2b meshed with each other are fixed at the angles by adjusting the angles by turning the shafts 23a and 23b protruding from the ends with a tool.

  Next, an operation of manufacturing a synthetic resin sheet in which two types of synthetic resins are arranged in a stripe pattern by the apparatus configured as described above will be described.

  First, the two different diameter rods 2a and 2b meshed with each other in the width direction multi-branch valve 10 are turned with a tool, and the ratio of the width of the small diameter portion 22 to the large diameter portion 21 at the inlet of the slit 14 of the feed block 1 is determined. adjust. That is, when the two different-diameter bars 2a and 2b are rotated in opposite directions, the width of the small-diameter portion 22 of the two different-diameter bars 2a and 2b at the entrance of the slit 14 increases, and the large-diameter portion It changes so that the width of 21 becomes narrow.

  For example, when it is desired to make the width of the devitrified molten synthetic resin wider than the width of the transparent molten synthetic resin, the width of the small diameter portion 22 for supplying the devitrified molten synthetic resin is set to be transparent from the opposite side. The angle of the two different-diameter bar members 2a and 2b engaged with each other is adjusted so as to be wider than the width of the small-diameter portion 22 that supplies.

  As shown in the enlarged sectional view of FIG. 3A, when the molten synthetic resin A is press-fitted through the left sub-manifold 13a from the left extruder (not shown), the inner wall and the left side of the left round hole 11a are shown. The molten synthetic resin A enters the slit 14 of the feed block 1 through a plurality of gaps surrounded by the small diameter portions 22 of the different diameter bar 2a. At this time, the molten synthetic resin B supplied from the right-side extruder (not shown) is blocked by the large-diameter portion 21 of the right-side different-diameter bar 2b.

  Similarly, as shown in the enlarged sectional view of FIG. 3B, when the molten synthetic resin B is press-fitted through the right sub-manifold 13b from the right extruder (not shown), the right round hole 11b The molten synthetic resin B enters the slit 14 of the feed block 1 through a plurality of gaps surrounded by the inner wall and the small-diameter portion 22 of the right-diameter bar 2b on the right side. At this time, the molten synthetic resin A supplied from the left-side extruder (not shown) is blocked by the large-diameter portion 21 of the left-side different-diameter bar 2a.

  Since the small-diameter portions 22 of the left and right different-diameter bars 2a and 2b are alternately arranged without gaps at the entrance of the slit 14, the two types of molten synthetic resins A and B press-fitted from both the left and right directions are joined alternately. In this state, they are arranged in a vertical stripe shape and discharged from the slit 14 in a plate shape.

  The two types of vertically striped molten synthetic resin discharged from the slits 14 of the multi-branch valve 10 in the width direction are thinned and widened by the T-die 3, and then molded into a synthetic resin sheet by the cooling roll 4 and wound. Thus, even if it is thinned and widened by the T-die 3, the ratio of the widths of the two types of synthetic resin is substantially the same as the ratio of the widths of the small diameter portions 22 of the two different-diameter bars 2a and 2b at the entrance of the slit 14. It is.

  A synthetic resin sheet in which two kinds of synthetic resins formed of a transparent part and a devitrified part thus produced are formed in stripes in the vertical direction, as shown in FIG. A packaging container in which the body part and the lid part are integrally connected via a connecting part that can be bent can be obtained, and can be used in various fields.

  Since it is desirable to mold the boundary between the transparent lid part and the devitrified body part so that it matches the foldable connecting part of the packaging container, when manufacturing the raw material of synthetic resin sheet molded into vertical stripes Next, adjust the angle of the different-diameter bar 2a, 2b of the multi-branch valve 10 in the width direction according to the shape of the packaging container to be molded, and set the ratio of the width between the transparent part and the devitrified part in advance. It's fine.

  In the embodiment described above, a transparent synthetic resin and a devitrified synthetic resin are described as examples of two types of synthetic resins, but a colored synthetic resin is applied instead of the devitrified synthetic resin. It may be.

A longitudinal sectional view showing an embodiment of a synthetic resin sheet manufacturing apparatus of the present invention, 1 is a cross-sectional view of the apparatus shown in FIG. A longitudinal sectional view for explaining the flow of two types of molten synthetic resins passing through the multi-branch valve in the width direction; The perspective view of the different diameter rod material used as the width direction multibranch valve of the apparatus shown in FIG. 1 and FIG. The perspective view which shows the state which meshed | engaged two different diameter bar materials, FIG. 4 is a front view of the different-diameter bar shown in FIG. The top view which shows the state which processes the synthetic resin sheet manufactured with the apparatus of this invention into a thin wall container, It is a perspective view which shows a part of process of manufacturing the synthetic resin sheet which has arrange | positioned two different conventional synthetic resins alternately in the width direction.

Explanation of symbols

1 Feed block 2a, 2b Different diameter bar
3 T-die
4 Cooling roll
10 Multi-branch valve in the width direction
11a, 11b Two round holes partially overlapping
12a, 12b Holes communicating with the sub manifold
13a, 13b Sub manifold
14 Slit
21 Large diameter part
22 Small diameter part

Claims (4)

Two round holes drilled in parallel so that a part of them overlaps, a slit opened downward from the overlapping part of the two round holes, and a thermoplastic melted by being drilled on the side of each of the round holes. A feed block having two manifolds for press-fitting molten synthetic resin;
Width formed by two different diameter rods that are inserted through the two round holes and whose diameter changes alternately between a large diameter portion and a small diameter portion in the longitudinal direction, and one large diameter portion meshes with the other small diameter portion. A directional multi-branch valve,
Two kinds of melted thermoplastic melted synthetic resins that have been press-fitted are joined alternately and arranged in a vertical stripe shape, and then discharged into a plate shape from the slits of the feed block, widened by a T-die, and cooled by a cooling roll. And then molding the sheet into a sheet.   The large-diameter portion of the two different-diameter bar members is composed of a wide portion and a narrow portion where the width continuously changes, and the small-diameter portion also includes a narrow portion and a width where the width continuously changes. The synthetic resin sheet manufacturing apparatus according to claim 1, comprising a wide portion.   The synthetic resin sheet manufacturing apparatus according to claim 2, wherein the width of the sum of the large-diameter portion and the small-diameter portion of the two different-diameter bars is the same over the entire circumference. A means for adjusting the ratio of the width between the large diameter portion and the small diameter portion of the two different diameter bars at the entrance of the slit by changing the angle of the two different diameter bars is provided. The synthetic resin sheet manufacturing apparatus according to claim 2 or claim 3.

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