JPS63224924A - Molding method and device for tubular body - Google Patents

Abstract

PURPOSE:To mold continuously a tubular body superior in pressure resistance, by a method wherein long-sized belts to which a hot-melt adhesive agent is applied are superposed and wound round on a mandrel by a plurality of specific rollers. CONSTITUTION:A hot-melt adhesive agent applied to beltlike bodies 1 each is melted, and tensile force is given in a longitudinal direction. The beltlike bodies 1 each are enlarged gradually to the whole width according to progress in a sphere where the beltlike bodies 1 each are stuck together. Then the beltlike bodies 1 each are led into a group of rollers 4-15, in a form along an external circumferential surface of a mandrel 3, and overlapping their positions partly one another and they are pressed. When a pressing sphere is kept transferring in a circumferential direction of the mandrel 3 through pressing force, the beltlike bodies 1 each are stuck together while releasing creases to be generated on the beltlike bodies 1 to its side fringe. The beltlike bodies 1 each can be stuck uniformly on the mandrel 3 by the group of the rollers 4-15 and a tubular body superior in pressure-resistant strength can be obtained.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method and an apparatus for continuously forming a flexible band-like body into a tubular body by polymerizing and adhering multiple layers. The present invention relates to a method for continuously forming a tubular body and an apparatus therefor.

(Prior Art) Conventionally, a method of forming a tubular body proposed in Japanese Patent Publication No. 60-35254 is known as this type of method.

In this method, a plurality of flexible strips are stacked while being shifted laterally so that their side edges are stepped, and the stacked strips are first stacked on both sides of the strips. These strips are simultaneously gradually bent around the mandrel to form a tubular shape and polymerized. The two side edges of the band-shaped body, which gradually increase in size toward the edge and which are offset from each other, are then joined to form a complete tubular body.

In this way, when forming a tubular body, the adhesive area is gradually expanded and molded, which is advantageous in that it is possible to prevent wrinkles from forming in the adhesive area of each strip.

In addition, when the adhesive used is a water-soluble adhesive when gradually expanding the bonded area, the adhesive remains liquid for a relatively long time after bonding, so the bonding area between the bonded strips remains Since they can be shifted from each other, even if the bonding area is gradually expanded, there is no need to pay much attention to the bonding work.

However, when such a water-soluble adhesive is used, it takes a long time for the adhesive to dry.

Further, when the molded tubular body is used as a container for storing liquid, it is necessary to provide a waterproof layer on the innermost layer or outermost layer, and in this case, it becomes extremely difficult to dry the adhesive. In such cases, it is preferable to use a hot melt adhesive that does not require drying.

However, when hot melt adhesive is used as an adhesive in such a molding method, each strip is firmly fixed at the same time as the strips are bonded.
If uniform adhesion is not performed on each strip even partially, wrinkles will occur between each strip, resulting in unbonded areas and reducing the pressure resistance of the tubular body. It is not possible to form a high-quality tubular body simply by gradually expanding the size of the tube.

(Problems to be Solved) The present invention eliminates such conventional inconveniences, and manufactures a tubular body with excellent pressure resistance by uniformly bonding each band formed into a tubular body using a hot melt adhesive. The purpose of the present invention is to provide a continuous molding method and apparatus for the same.

(Means for Solving the Problems) In order to achieve the above object, the first aspect of the present invention is to provide a plurality of elongated strips made of a flexible material so that the side edges thereof are stepped. The strips are polymerized and supplied at different positions, and then gradually bent along the mandrel and bonded with an adhesive interposed between the strips to form a tubular body, and the edges on both sides which are shifted from each other are joined. in a method of forming a complete tubular body by continuously supplying a plurality of elongated strips having a molten hot melt adhesive on at least one side while applying tension in the longitudinal direction at intervals from each other. The spacing between the strips is maintained until just before they are bonded to each other, and a force is applied to press the strips against a mandrel disposed in the longitudinal direction of the innermost strip at a midpoint between both edges of the innermost strip. A second aspect of the present invention is characterized in that it comprises a step of forming a tubular body by continuous linear transfer in the circumferential direction of a mandrel. , the side edges of the strips are staggered and superimposed, and then gradually bent along the mandrel and bonded with an adhesive interposed between the strips to form a tubular body. In this apparatus, a plurality of elongated strips each having a hot melt adhesive in a molten state on at least one side are spaced apart from each other in an apparatus for forming a complete tubular body by joining the two side edges which are offset from each other. A device that applies tension in the longitudinal direction and continuously supplies the material;
A mandrel disposed in the longitudinal direction of the innermost strip at an intermediate position between both side edges of the innermost strip and a plurality of rollers shaped along the outer peripheral surface of the mandrel are shifted in the longitudinal direction of the mandrel and A device for continuously arranging the belt-shaped body over the entire circumference of the mandrel with one roller as a reference, partially overlapping each other in the circumferential direction of the mandrel, and pressing the belt-shaped body against the mandrel with each roller; and a hot melting device for the belt-shaped body. and a device that heats and maintains the adhesive in a molten state at least until it reaches the roller group.

The flexible strip used in the present invention is made of a material such as paper or plastic metal foil. Moreover, you may use these materials in combination. In particular, the present invention is suitable when the innermost and outermost layers of the strip to be polymerized are waterproofed.

The belt-shaped body is made of a continuous long sheet material, and the formed tubular body is appropriately cut into predetermined dimensions for use.

The hot melt adhesive used in the present invention may be a known and commonly used adhesive (polyethylene alone, ethylene and ethylene copolymer, ethylene vinyl acetate copolymer, ethylene methyl methacrylate copolymer, ethylene ethyl acrylate copolymer, etc.). Polymer, ethylene methyl acrylate copolymer, ethylene ethyl acrylate maleic anhydride copolymer, ethylene acrylic acid copolymer, ethylene methacrylic acid copolymer, ionomer resin, polyamide resin,
Polyester resins, nylon resins, polypropylene resins, vinyl acetate copolymer resins, polymethyl methacrylate resins, and the like may be used alone or in combination.

A hot melt adhesive is applied and formed on at least one side of the strip. A hot melt adhesive may be applied to both surfaces of the strip forming the intermediate layer. This hot melt adhesive can be applied to a strip in advance and reheated just before the step of forming a tubular object to melt it, or it can be used to melt the hot melt adhesive when forming a tubular object. It may be formed by applying an adhesive. It is necessary to heat this hot melt adhesive so that it remains molten until the process of forming the tubular body.

A plurality of strips provided with the molten hot-melt adhesive are stacked at different positions and spaced from each other so that their side edges become step-like, and each strip is Continuously feed by applying tension in the longitudinal direction. When continuously supplied under such tension, it helps to maintain the spacing between the strips until just before they are formed into a tubular body.

A mandrel having an outer shape that defines the shape of the tubular body in the longitudinal direction is disposed at the intermediate position between both edges of the innermost layer of the strip-shaped body that is continuously supplied in this way, and the strip-shaped body is Bend it along the plane and form it into a tubular body. At this time, the pressing force applied to the band-shaped body for bending along the mandrel is continuously transferred linearly in the circumferential direction of the mandrel and applied over the entire circumference of the mandrel, thereby forming the band-shaped body into a tubular body. is important.

(Function) The present invention maintains the hot melt adhesive applied to each strip in a molten state until each strip is bonded, and
A force that applies tension to each strip in the longitudinal direction and maintains the distance from each other until just before the strips are bonded, and then presses each strip against a mandrel arranged in the longitudinal direction of the innermost layer. is continuously transferred linearly in the circumferential direction of the mandrel and formed into a tubular body, so that the area where each strip is bonded gradually increases as the strip progresses, as seen from the transverse position of the strip. When viewed in the longitudinal direction of the strip, it gradually expands from the circumference position of the mandrel toward the entire circumference, so that the area of each strip that is not bonded extends in the width direction of each strip. On the other hand, it also decreases gradually in the longitudinal direction of the strip from a certain circumferential position of the mandrel towards the entire circumferential surface, during which it is free from the adhesive area.

Then, each strip is bonded while the wrinkles and the like that occur on each strip when the pressing area is shifted in the circumferential direction of the mandrel due to this pressing force are released to the side edges thereof.

Such adhesion is achieved by shifting the positions of a plurality of rollers shaped along the outer peripheral surface of the mandrel in the longitudinal direction of the mandrel and partially overlapping each other in the circumferential direction of the mandrel with one roller as a reference. This is possible by arranging the rollers over the entire circumference and pressing each roller against the mandrel via a strip. In particular, the tubular body to be molded has a circular or elliptical cross section, the mandrel has a circular or elliptical cross section, the pressing surface of each roller is an arcuate surface along the outer peripheral surface of the mandrel, and the rotation of each roller This is effectively carried out by providing a shaft perpendicular to the axis of the mandrel and pressing the mandrel at an intermediate position of the arcuate surface through the band-shaped body.

(Example) A more detailed explanation will be given below with reference to the drawings showing an example of implementation of the present invention.

1 and 2 are schematic diagrams of an example of an implementation apparatus for implementing the molding method of the present invention.

A is a feeding device that continuously feeds out four paper strips 1;
B is a preheating device that heats and uniformly dries each of the strips 1 that have been fed out, and C is a preheating device that heats each of the strips 1 that have been fed out and dries them uniformly; D is a positioning device for positioning, D is an adhesive application device for applying hot melt adhesive to each strip 1, and E is a positioning device for each strip 1.
F is a heating device equipped with a heating means to keep the adhesive applied to the adhesive in a molten state; F is a forming device that bends each strip along a mandrel to form a tubular body; A drawing device H is a cutting device that cuts the drawn tubular body into an appropriate length.

After each strip 1 is shaped, tension is applied in its longitudinal direction by the dispensing device G until it reaches the shaping device F.

FIG. 3 shows the heating device E, which injects heated air from a nozzle 2 containing a heater into the gap between each strip 1 to melt the hot melt adhesive applied to each strip 1. And as shown in the fourth figure, a plurality of nozzles are used to ensure that the hot melt adhesive of each strip 1 to be bent and formed by the forming device F is in a melted state immediately before being bonded. 2 was established.

5 and 6 show a forming apparatus F, in which a molding device F is provided which extends in the longitudinal direction of each continuously supplied strip (not shown) at an intermediate position between both side edges of the strip located in the innermost layer of the strip. , a mandrel 3 having a circular cross section and extending to the drawing device G and the cutting device H.

Around the mandrel 3, a plurality of rollers 4 to 15 are provided with positions shifted in the direction of movement of the belt-like bodies for bending each belt-like body along the outer peripheral surface of the mandrel 3 and forming it into a tubular body. Each of the rollers 4 to 15 basically has an arcuate surface corresponding to a part of the circumferential shape of the outer peripheral surface of the mandrel 3, and each of the rollers has a rotation axis perpendicular to the axis of the mandrel 3. and installed it.

The rollers 4 to 15 move the strip onto the mandrel, as shown in FIG. 6 and FIG. 7, which schematically shows the arrangement of the rollers.
A roller 4 that first comes into pressure contact with the innermost layer strip 1a was provided at a position midway between both side edges of the innermost layer strip 1a. Then, the roller 4
Rollers 5 and 6 located downstream of the mandrel 3 were provided in both directions of the mandrel 3 at positions where their respective pressing surfaces overlapped with a portion of the pressing surface of the roller 4. Furthermore, a roller 7 downstream of the roller 5.6 was provided so that the pressure contact surfaces of the roller 5 and the roller 8 overlapped with the roller 6 at a portion of each other. Further, a roller 9 downstream of the roller 7.8 is provided with the roller 7, and a roller 10 with the roller 8 are provided so that their pressure contact surfaces partially overlap each other, and the other rollers 11 to 15
The rollers 4 to 15 were provided in the same manner so that the pressure contact surfaces of the rollers 4 to 15 covered the entire circumference of the mandrel 3.

Each of the rollers 4 to 15 includes cylinders 16 to 27 that press the center of each arc-shaped pressing surface toward the mandrel 3. 28 is a support roller that supports and guides the tubular body molded by the molding device F.

When configured in this way, the rollers 4 to 15 are
With the roller 4 as a reference, it is possible to apply a force that presses each strip to the mandrel 3 in a continuous linear manner in the circumferential direction of the mandrel 3.

Furthermore, the process of forming the tubular body will be explained with reference to FIG.

First, as shown in FIG. 7(A), each strip 1 is pressed against a mandrel 3 by a roller 4 and polymerized and bonded with an intervening hot melt adhesive. At this time, the pressing force in the central region 4a of the pressing surface of the roller 4 is maximum, and the pressing force becomes weaker toward the side edges of the pressing surface. Therefore, in the central region 4a, each strip 1 is firmly adhered, but the adhesion gradually becomes insufficient toward the side edges.

Next, as shown in FIG. 7CB), each strip 1 is pressed by a roller 5.6 to enlarge the bonded area while maintaining a distance from each other except for the portion bonded by the roller 4. At this time, since the central areas 5a and 6a of the pressing surfaces of the rollers 5.6 are shifted in the direction of both sides of the mandrel 3, the rollers 4 are able to completely adhere the areas where the adhesion was insufficient. Expand the adhesive area. Similarly, Figure 7 (
As shown in C) to (E), the rollers 8 to 12 gradually linearly transfer the pressing force toward both side edges of each strip 1 to bend each strip 1 and form it into a shape along the mandrel 3. do.

At this time, one side edge of each strip 1 is bent by the roller 11 so as to contact the mandrel 3 earlier than the other side edge, and then, as shown in FIGS. 7(F) to (H), the rollers 13 to 1
5, the other side edge is overlapped and bonded to form a completely bonded tubular body.

(Effects) According to the present invention, a plurality of elongated strips each having a molten true-melt adhesive on at least one side are placed in the middle of both side edges of the innermost layer of the strip in the longitudinal direction of the strip. When forming a tubular body by gradually bending it along a provided mandrel and adhering it to each other, tension is applied to the belt-shaped body in its longitudinal direction to maintain a distance from each other and the belt-shaped body is continuously fed, and hot-melt adhesive is also used. The adhesive is maintained in a molten state until the bonding position is reached, and the bonding area of each strip is gradually expanded while bonding.
By applying the force that presses the strip onto the mandrel by continuously transferring it in the circumferential direction of the mandrel, it is possible to form the tubular body without any trouble even using hot melt adhesive, and each strip can be formed uniformly. A bonded tubular body with excellent pressure resistance can be obtained.

In addition, a plurality of rollers shaped along the outer peripheral surface of the mandrel are shifted in the longitudinal direction of the mandrel, and the cholera
By using a device in which two rollers are arranged continuously over the entire circumference of the mandrel in a manner that partially overlaps each other in the circumferential direction of the mandrel, and each roller is pressed against the mandrel through the strip, the hot melt A tubular body can be formed by uniformly bonding each strip with adhesive.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 to Fig. 7 show an example of the implementation of the present invention, in which Fig. 1 is a plan view thereof, Fig. 2 is a front view, and Fig. 3 is a plan view of the heating device. Figure 4 is a diagram for explaining the heating process of hot melt adhesive by a heating device, Figure 5 is a front view of the molding device, Figure 6 is a sectional view taken along the line Vl-VI in Figure 5, FIG. 7 is a diagram for explaining the molding process. 1... Band-shaped body 3... Mandrel 4-15.
··roller

Claims (1)

[Claims] 1. A plurality of long strips made of flexible material are stacked and supplied with their side edges staggered so that they are gradually moved along a mandrel. In the method of bending, the band-shaped body is bonded with an adhesive interposed between the strips to form a tubular body, and the mutually offset side edges are joined to form a complete tubular body. A process of continuously supplying a plurality of long strips with melt adhesive while applying tension in the longitudinal direction at intervals, and holding the intervals between the strips until just before they are bonded to each other. Forming a tubular body by continuously linearly transferring the force that presses the strip to a mandrel disposed in the longitudinal direction of the strip in the circumferential direction of the mandrel at an intermediate position between both side edges of the strip. 2, a method for forming a tubular body characterized by comprising the steps of: a plurality of elongated strips made of a flexible material are stacked with their positions shifted from each other so that their side edges become step-like; In an apparatus for forming a tubular body by gradually bending the strip along a mandrel and gluing it with an adhesive interposed between the strips, and joining the mutually shifted side edges to form a complete tubular body. , a device for supplying a plurality of elongated strips each having a hot melt adhesive in a molten state on at least one side while applying tension in the longitudinal direction at a distance from each other; A mandrel disposed in the longitudinal direction of the strip and a plurality of rollers shaped along the outer peripheral surface of the mandrel are shifted in the longitudinal direction of the mandrel, and the circumferential direction of the mandrel is shifted with respect to one of these rollers as a reference. a device for continuously arranging the strips over the entire circumference with their positions partially overlapping each other and pressing the strips against the mandrel with each roller; and a device for applying the hot melt adhesive of the strips to at least the roller group. A device for forming a tubular body (3) characterized by comprising a device for heating and maintaining the tubular body in a molten state, wherein the mandrel has a circular or elliptical cross-sectional shape, and the pressure contact surface of the roller is along the outer circumferential surface of the mandrel. The tubular body according to claim 2, wherein the roller has an arcuate surface and a rotation axis of the roller is perpendicular to the axis of the mandrel, and the strip is pressed against the mandrel at an intermediate position of the arcuate surface. The body forming device 4 is characterized in that the mandrel and the roller that first presses the strip against the mandrel are disposed opposite to each other at intermediate positions between both edges of the innermost strip among the strips. A device for forming a tubular body according to claim 2