JP5181812B2 - Inflation molding machine - Google Patents

Description

  The present invention relates to an inflation molding machine, and more particularly, to an inflation molding machine that improves the problem of wrinkles that occur when a cylindrical film is folded into a sheet.

  Conventionally, an inflation molding machine in which air is supplied from the inside of a film extruded from an extruder and the film is blown into a cylindrical shape is well known (see, for example, Patent Documents 1 and 2). In such an inflation molding machine, the cylindrical film blown into a cylindrical shape is deformed into a flat shape by a guide means while being conveyed, and then folded into a sheet shape by a pair of pinch rolls, and then rolled into a winding core. It is designed to be wound around.

The above-described inflation molding machine has no problem when the film alone is subjected to inflation molding, but when the cylindrical film provided with a tack layer such as an adhesive on the outer peripheral surface is subjected to inflation molding, as shown in FIG. Since the cylindrical film 23 deformed in a flat shape by the guide means 22 adheres to the outer peripheral surfaces of the pair of pinch rolls 20 and 21 in a loose state (adheres), the pinch rolls 20 and 21 are pressed and folded into a sheet shape. There was a problem that wrinkles were generated in the cylindrical film 23 that was in close contact therewith.
WO2004 / 110735 publication JP 2005-125499 A

  An object of the present invention is to provide an inflation molding machine capable of preventing the generation of wrinkles even with a cylindrical film provided with a tack layer such as an adhesive on the outer peripheral side.

  The inflation molding machine of the present invention that achieves the above-described object is to fold a cylindrical film deformed into a flat shape on the conveyance side of a guide means that deforms into a flat shape while conveying the blown cylindrical film. In the inflation molding machine in which a pair of pinch rolls is arranged, the pair of pinch rolls is composed of a pinch roll having a diameter of 20 to 50 mm.

  According to the present invention described above, by reducing the diameter of the pinch roll as described above, it becomes difficult for the cylindrical film deformed into a flat shape to adhere to the pinch roll. Is possible.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows an embodiment of an inflation molding machine according to the present invention. This inflation molding machine extrudes a film composed of a thermoplastic resin or a thermoplastic elastomer composition obtained by blending a thermoplastic resin component and an elastomer component. 1 single screw extruder 1, 2nd single screw extruder 2 for extruding an adhesive agent, and cylindrical die 3 connected to extrusion ports 1X and 2X of both single screw extruders 1 and 2 are provided.

  The first single-screw extruder 1 kneads and melts a film material made of a thermoplastic resin or a thermoplastic elastomer composition charged from a hopper 1A by a screw 1C that rotates in a cylinder 1B, and passes from an extrusion port 1X to a cylindrical die 3. To send. The second single-screw extruder 2 is also configured to knead and melt the adhesive material charged from the hopper 2A with a screw (not shown) that rotates in the cylinder 2B and supply it to the cylindrical die 3 from the extrusion port 2X.

  The cylindrical die 3 is configured such that a cylindrical film F in which an adhesive layer (tack layer) is laminated on the outer peripheral side from the upper lip port 3A is pushed upward. Compressed air is sent from the center of the lip port 3A, whereby the cylindrical film F is blown to a predetermined diameter.

  An air ring 4 for cooling the expanded cylindrical film F is disposed above the cylindrical die 3. The air ring 4 blows cooling air to the cylindrical film F from the annular blowing port 4A, and cools the cylindrical film F conveyed upward.

  Above the air ring 4 is provided guide means 5 for deforming the cooled cylindrical film F into a flat shape while transporting it. The guide means 5 has a pair of guide members 5A and 5A arranged to face each other. As shown in FIG. 2, each guide member 5 </ b> A includes a rectangular frame 5 </ b> A <b> 1 and a plurality of guide roller groups 5 </ b> A <b> 2 arranged on the frame 5 </ b> A <b> 1 in the vertical direction that is the conveyance direction of the cylindrical film F. . Each guide roller group 5A2 extends in the transverse direction intersecting the conveyance direction of the cylindrical film F, and a plurality of guide rollers R are rotatable at predetermined intervals on an axis M attached to both ends of the frame 5A1. Are arranged. The pair of guide members 5A and 5A are arranged in an inclined shape as shown in FIG. 1, and the inclination angle can be changed depending on the size of the cylindrical film F to be folded.

  A pair of pinch rolls 6, 7 for folding the cylindrical film F deformed into a flat shape by the guide means 5 into a sheet shape is disposed above the guide means 5 on the conveying side. One pinch roll 6 is a drive roll, and the other pinch roll 7 is a rotatable follower roll. The other pinch roll 7 is movable in the direction approaching and separating from the one pinch roll 6, and the pinch roll 7 is urged by an urging means (not shown), whereby the cylindrical film F is pinched by the pinch rolls 6, 7. The cylindrical film F sandwiched between them and thereby deformed into a flat shape is pressed and folded into a sheet shape.

  The pair of pinch rolls 6 and 7 is composed of a pinch roll having a diameter of 20 to 50 mm. The pinch rolls 6 and 7 made of stainless steel are coated with fluororesin on the outer peripheral surfaces 6x and 7x with which the cylindrical film F deformed into a flat shape comes into contact, thereby making it difficult to attach the cylindrical film F. ing. Preferable examples of the fluororesin to be coated include polytetrafluoroethylene. A silicone resin or the like may be coated instead of the fluororesin.

  8 is a winding means for winding the cylindrical film F folded into a sheet around the winding core 8A. The cylindrical film F folded into a sheet by a pair of pinch rolls 6 and 7 includes a plurality of cylindrical films F. It is wound around the winding core 8A through the guide roll 9.

  In the above-described inflation molding machine of the present invention, the film material introduced from the hopper 1A is fed to the cylindrical die 3 while being kneaded and melted by the screw 1C rotating in the cylinder 1B of the first single-screw extruder 1, while the hopper 2A. Is supplied to the cylindrical die 3 while being kneaded and melted by a screw rotating in the cylinder 2B.

  A cylindrical film F in which an adhesive layer is laminated on the outer peripheral side is extruded upward from the lip port 3A of the cylindrical die 3. At that time, the cylindrical film F is inflated to a predetermined diameter by compressed air supplied from the center of the lip port 3A. Cooling air is blown from the blowing port 4A of the air ring 4 to the blown cylindrical film F, and the cylindrical film F is cooled.

  The cooled cylindrical film F is conveyed to the guide means 5, where it is deformed into a flat shape by the pair of guide members 5A, 5A so that the short diameter side is gradually reduced. The cylindrical film F deformed into a flat shape is then carried into the pinch rolls 6 and 7.

  At that time, as shown in FIG. 3, since the diameter of the pair of pinch rolls 6 and 7 is as small as 50 mm or less, the cylindrical film F is pinched between the pair of pinch rolls 6 and 7 without adhering to the outer peripheral surface. Folded into a sheet. The cylindrical film F folded into a sheet shape by the pinch rolls 6 and 7 is wound around the winding core 8 </ b> A of the winding means 8 through the plurality of guide rolls 9 in a roll shape.

  The present inventor has intensively studied about the occurrence of wrinkles in a cylindrical film having a tack layer such as an adhesive on the outer peripheral surface, and has found the following.

  Conventionally, a pair of pinch rolls having a diameter of 100 mm or more is generally used. In such a pinch roll, as shown in FIG. 4, the cylindrical film 23 deformed in a flat shape is attached to the outer peripheral surface of the pair of pinch rolls 20, 21. Even when the pinch roll is small, it was found that the pinch roll having a diameter of 100 mm or more adheres to the cylindrical film 23 deformed into a flat shape in substantially the same region of the outer peripheral surface.

  Therefore, attention was paid to the diameter of the pinch roll. The smaller the diameter of the pinch roll, the shorter the outer peripheral length. If the cylindrical film 23 deformed flat in the same region adheres, the attached area can be reduced. Therefore, when the diameter of the pinch roll is reduced stepwise and the adhesion relationship between the pinch roll and the film is examined, a cylindrical film deformed into a flat shape with 50 mm as a boundary may be difficult to adhere to the pinch roll. all right. Probably, it is presumed that the film became difficult to adhere because the weight of the film was superior due to the relationship between the weight of the film and the contact area.

  On the other hand, it was found that wrinkles are easily generated even when the diameter of the pinch roll is smaller than 20 mm. For example, although the length of the pinch rolls 6 and 7 used for producing the cylindrical film F for the inner liner layer is usually 400 to 1500 mm, the diameter of the pinch rolls 6 and 7 having such a length is If the diameter is smaller than 20 mm, there arises a problem of bending deformation due to insufficient strength. As a result, even if the diameter is too small, the cylindrical film F adheres to the pinch rolls 6 and 7 and wrinkles easily occur. Furthermore, it was also found that the cylindrical film F having a desired size is difficult to obtain because the dimension of the formed cylindrical film F is not stable.

  Therefore, in the present invention, the pinch rolls 6 and 7 are constituted by pinch rolls having a diameter smaller than the conventional range within the above range. Thereby, since it can suppress that the cylindrical film F which provided the contact bonding layer in the outer peripheral side adheres to the outer peripheral surface of the pinch rolls 6 and 7, the wrinkle problem of the cylindrical film F resulting from adhesion is improved. be able to.

  In the present invention, the distance L between the guide means 5 and the pinch rolls 6 and 7 is preferably set to 100 mm or less in the conveying direction of the cylindrical film F, whereby the cylindrical film F deformed into a flat shape is obtained. It is possible to suppress loosening between the guide means 5 and the pinch rolls 6 and 7 and to suppress adhesion to the pinch rolls 6 and 7.

  That is, the cylindrical film F in which the adhesive layer is laminated on the outer peripheral side has a large friction with the pinch rolls 6 and 7, so that the flow is not smooth and is conveyed while being slightly rubbed. Thereby, a bending force acts on the cylindrical film F between the guide means 5 and the pinch rolls 6 and 7. When the distance L becomes long, the rigidity of the cylindrical film F loses the bending force, causes bending, and becomes loose. If it is conveyed in that state, it will adhere to the pinch rolls 6 and 7 and wrinkles will occur, but this can be avoided by shortening the distance L to 100 mm or less. Preferably, it is 60 mm or less.

  The lower limit value of the distance L may be in a range where the pinch rolls 6 and 7 do not come into contact with the guide means 5, and may be about 20 mm, for example. The distance L mentioned here is the position of the guide means 5 where the pinch rolls 6 and 7 pinch the point M and the cylindrical film F last contact (in the case of the guide member 5A shown in FIG. It is the length measured along the conveyance direction of the cylindrical film F between the guide roller and the contact position).

  Preferred examples of the cylindrical film F molded in the present invention include those used for the inner liner layer of a pneumatic tire. In this case, the cylindrical film F has a diameter (inner diameter) of 250 to 800 mm and a thickness including an adhesive layer of 0.01 to 0.3 mm.

  In the above embodiment, the cylindrical film F extruded upward from the cylindrical die 3 is folded into a sheet shape by the pair of pinch rolls 6 and 7 while being conveyed upward, but the cylindrical shape extruded downward from the cylindrical die 3 is used. The film F may be folded into a sheet shape by a pair of pinch rolls 6 and 7 while transporting the film F downward, and the guide means 5 deforms into a flat shape while transporting the blown cylindrical film F. It can be applied to any inflation molding machine in which a pair of pinch rolls 6 and 7 for folding a cylindrical film F deformed into a flat shape into a sheet shape is disposed on the conveying side.

  The present invention can be preferably used for forming a cylindrical film F provided with a tack layer such as an adhesive on the outer peripheral side, but it can also be used for forming a cylindrical film having no tack layer as a matter of course. .

  Forming machines 1 to 4 of the present invention having the configuration shown in FIG. 1 (Example 1), in which the diameter of a pair of pinch rolls made of stainless steel and the presence or absence of coating of fluororesin (polytetrafluoroethylene) are as shown in Table 1. -4) and comparative molding machines 1 to 3 (Comparative Examples 1 to 3), a cylindrical film having an adhesive layer provided on the outer peripheral side was molded.

  The inner diameter and thickness of the cylindrical film to be molded, and the distance L are as shown in Table 1. Moreover, the thermoplastic elastomer composition which has a mixing | blending shown in Table 2 was used for the cylindrical film, and the adhesive agent which has a mixing | blending shown in Table 3 was used for the contact bonding layer.

  While measuring the dimension of the shape | molded cylindrical film, the presence or absence of wrinkle generation | occurrence | production and the adhesion state to a pinch roll were observed visually, The result shown in Table 1 was obtained. The film dimension was evaluated as good when the cylindrical film inner diameter was within ± 30 mm, and unstable when it was larger.

  From Table 1, it can be seen that the present invention can prevent the generation of wrinkles. It can also be seen that adhesion can be avoided by coating the pinch roll with a fluororesin.

It is front explanatory drawing of the inflation molding machine of this invention. It is explanatory drawing of the guide member seen from the arrow A direction of FIG. It is explanatory drawing of the cylindrical film conveyed between a guide means and a pair of pinch rolls. In the conventional apparatus, it is explanatory drawing of the cylindrical film conveyed between a guide means and a pair of pinch rolls.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st single screw extruder 2 2nd single screw extruder 3 Cylindrical die 4 Air ring 5 Guide means 5A Guide member 5A2 Guide roller group 6,7 Pinch roll 6x, 7x Outer peripheral surface 8 Winding means F Cylindrical film R Guide roll

Claims (5)

  In an inflation molding machine in which a pair of pinch rolls for folding a cylindrical film deformed into a flat shape into a sheet shape is arranged on the conveyance side of a guide means that deforms into a flat shape while conveying a blown cylindrical film, An inflation molding machine in which the pair of pinch rolls is composed of a pinch roll having a diameter of 20 to 50 mm.   The inflation molding machine according to claim 1, wherein the pinch roll is made of stainless steel, and an outer peripheral surface of the pinch roll with which the cylindrical film contacts is coated with a fluororesin.   The guide means has a pair of guide members arranged so as to face each other, and each guide member has a guide roller group in which a plurality of rotatable guide rollers are arranged in a direction intersecting the conveyance direction of the cylindrical film. The inflation molding machine according to claim 1, wherein a plurality of them are arranged in the conveying direction.   The inflation molding machine according to claim 1, 2 or 3, wherein a distance L between the guide means and the pair of pinch rolls is 100 mm or less in a conveying direction of the cylindrical film.   The inflation molding machine according to claim 1, wherein the cylindrical film has a tack layer on an outer peripheral surface.

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