JP2005161726A - Foamed tubular product and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a foamed tubular product which is light in weight, simple in production process, economically advantageous, and excellent in mounting properties, absorbs sound, and insulates heat and a method for producing the product. <P>SOLUTION: The product is made of a sheet material 11 containing a foamed synthetic resin as a main component and has a shape with a prescribed product shape expanded in the tube direction by vacuum forming. An expanded object 20 having joined collar parts 22 and 23 integrally in the end parts on both sides in the tube direction is joined integrally in the joined collar parts and formed in a prescribed product shape. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a tubular product such as an air duct for automobiles, and more particularly to a foamed tubular product made of a sheet material mainly composed of a synthetic resin foam and a method for producing the same.

  Conventionally, tubular products such as air conditioning air ducts for automobiles are generally manufactured by blow molding (see, for example, Patent Document 1). However, this type of blow-molded product is not easily molded when the tube product has a bent shape, and requires special devices and techniques including a mold. Therefore, it was never economically advantageous.

By the way, this kind of tubular product is preferably as light as possible from the viewpoint of equipment or workability, and preferably can be deformed to some extent from the viewpoint of attachment. Of course, it is desirable that it is excellent in economic efficiency such as manufacturing cost.
Japanese Patent Laid-Open No. 9-68117

  The present invention has been made in view of these points, and is a novel foamed tubular product that is lightweight, has a simple manufacturing process, is economically advantageous, has excellent mounting properties, and has sound absorption and heat insulation properties, and its The manufacturing method is provided.

  That is, the invention of claim 1 is made of a sheet material mainly composed of a synthetic resin foam, and has a shape obtained by expanding a predetermined product shape along the tube direction by vacuum forming, and on both sides in the tube direction. The present invention relates to a foamed tubular product characterized in that an expanded product integrally having a joint flange at an end is joined to the joint flange and formed into a predetermined product shape.

  The invention according to claim 2 relates to the foamed tubular product according to claim 1, wherein a thin-walled portion, a groove portion, or a bellows portion is integrally formed on the bent portion of the expanded product by vacuum forming.

  Further, the invention of claim 3 relates to a method for producing the foamed tubular product, wherein the step of preheating a sheet material mainly composed of a synthetic resin foam to a shapeable temperature and the sheet material by vacuum forming A step of forming the product shape into an expanded shape having an expanded shape along the tube direction and integrally having joint flanges at both ends in the tube direction; and The present invention relates to a method for producing a foamed tubular product, comprising a step of joining joint joint portions.

  According to a fourth aspect of the present invention, there is provided the manufacturing of the foamed tubular product according to the third aspect, wherein, in the expanding material forming step, a thin wall portion or a groove portion or a bellows portion for bending is integrally formed on the sheet material by vacuum forming. Related to the method.

  According to the foamed tubular product according to the invention of claim 1, the foamed tubular product is made of a sheet material mainly composed of a synthetic resin foam, has a shape in which a predetermined product shape is expanded along the pipe direction by vacuum forming, and Since the widened product having joint joints integrally at both ends in the tube direction is joined at the joint joints and formed into a predetermined product shape, it is lightweight and has a manufacturing process. However, it has been possible to provide a foamed tubular product that is simple and economically advantageous, has excellent mounting properties, and has sound absorption and heat insulation properties.

  Further, according to the invention according to claim 2, since the thin-walled portion, the groove portion, or the bellows portion is integrally formed by the vacuum forming at the bent portion of the expanded product, the bending becomes easier and the deformation is achieved. It is possible, has excellent shape retention, improves workability during mounting, and increases durability.

  In the manufacturing method of claim 3, the step of preheating the sheet material mainly composed of the synthetic resin foam to a formable temperature and the sheet material by vacuum forming a predetermined product shape in the tube direction. A step of forming into a widened product having a shape that extends along the pipe and integrally having joint flanges at both ends in the tube direction, and the joint flange of the widened material are joined together Since it is characterized by having a process, it is easy and easy with an inexpensive vacuum mold without the need for complicated equipment and equipment including expensive molds like conventional blow molding. A foamed tubular product can be produced at low cost.

  Further, according to the invention of claim 4, in the expanding material forming step, a thin wall portion or a groove portion or a bellows portion for bending is integrally formed in the sheet material by vacuum forming. It is possible to manufacture a foamed tubular product having a complicated bent shape easily and inexpensively.

  The present invention will be described below with reference to the accompanying drawings. 1 is a perspective view of a foamed tubular product according to one embodiment of the present invention, FIG. 2 is a perspective view of an expanded product of the foamed tubular product of FIG. 1, and FIG. 3 is a perspective view showing another example of the expanded product. FIG. 4, FIG. 4 is a sectional view of an expanded material, FIG. 5 is a sectional view of another expanded material, FIG. 6 is a sectional view of yet another expanded material, and FIG. 7 is a partially enlarged sectional view of a sheet material. FIG. 8 is a schematic cross-sectional view showing the vacuum forming process of the expanded product.

  A foamed tubular product 10 shown in FIG. 1 is used as an air duct for air conditioning of an automobile. As shown in FIG. 2, the foamed tubular product 10 is made of a sheet material 11 mainly composed of a synthetic resin foam and is formed by vacuum forming. The open product 20 is integrally joined at the joint flanges 22 and 23 and formed into a predetermined product shape S. The expanded product 20 has a shape obtained by expanding a predetermined product shape S along the tube direction, and joint flanges 22 and 23 are integrally formed at both ends in the tube direction. . In the figure, reference numeral 25 denotes a bellows portion formed in the bent portion B.

  The sheet material 11 is mainly composed of a synthetic resin foam, and is made of a synthetic resin foam sheet or a laminated sheet thereof that can be vacuum formed. Examples of the synthetic resin foam include polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), polyvinyl chloride (PVC), expanded polystyrene (PSP), and polyurethane (PU). As the expansion ratio, it is preferable to use a foam molded product of 5 to 50 times, in particular, the expansion ratio is about 25 times for polypropylene, about 10 to 30 times for polyethylene, about 5 times for polyethylene terephthalate, etc. Those are preferably used.

  As shown in the sectional view of FIG. 7, the sheet material 11 made of a synthetic resin foam constitutes a porous structure composed of an internal cell layer 15 having a large number of bubbles 16 and a surface skin layer 17. Due to this porous structure of the sheet material 11, the foamed tubular product 10 made of the sheet material 11 is lighter than a conventional blow-molded tubular product, and can obtain a heat insulating effect and a sound absorbing effect.

  The expanded shape of the expanded product may be any shape as long as it can be molded by vacuum forming. As can be seen from the cross-sectional view of FIG. 4, the expanded product 20 of FIG. 2 has a small expansion opening, but because of the processing of the sheet material 11 mainly composed of synthetic resin foam, Processing is possible even in a so-called undercut portion. On the other hand, the expanded product 20A in FIG. 3 has an increased degree of expansion as shown in the sectional view in FIG. Further, the expanded product 20B shown in the cross-sectional view of FIG. 6 is a processing example in which almost no undercut portion is generated. The shapes of these expanded products 20, 20A, 20B may be appropriately determined according to conditions such as the material of the sheet material, the bent shape to be molded, or the mold design requirements.

  A thin-walled portion, a groove portion, or a bellows portion 25 may be integrally formed with the bent portion B of the spread-like material 20, 20A, 20B by vacuum forming. In addition to the illustrated bellows portion 25 that is a portion that is bent as the shape S of the product 10, the bent portion B includes a portion that is bent when the expanded objects 20, 20A, 20B are joined. Reference numeral 26 of the expanded product 20A in FIG. 5 represents a thin portion, and reference numeral 27 of the expanded product 20B in FIG. 6 represents a groove portion. The thin portion 26 or the groove portion 27 or the bellows portion 25 facilitates bending at the bent portion B, easily creates the shape of the foamed tubular product 10 and enhances its shape retention. Workability at the time of joining and mounting is improved, and durability is also increased.

  In this embodiment, the sheet material 11 is made of a single synthetic resin foam. However, the present invention is not limited to this, and an appropriate sheet material such as a nonwoven fabric can be laminated to form a laminated structure. . Thus, by making the foamed tubular product 10 into a laminated structure, the rigidity and strength of the foamed tubular product 10 can be adjusted, and further physical properties such as a heat insulating effect and a sound absorbing effect can be further improved. It becomes.

  Next, a method for producing the foamed tubular product 10 defined as the invention of claim 3 will be described. The manufacturing method of the said foamed tubular product 10 has a preheating process, a vacuum forming process, and a joining process.

  First, the sheet material 11 is preheated and softened to a predetermined temperature that can be shaped in a known preheating device (for example, a heater) (not shown). The preheating temperature varies depending on the synthetic resin foam material constituting the sheet material 11, but suitable preheating temperatures of each material are, for example, approximately 100 to 110 ° C for polypropylene, approximately 80 to 90 ° C for polyethylene, and approximately 80 to 90 ° C for polyethylene terephthalate. About 220 ° C is a standard.

  As shown in FIG. 8, the preheated sheet material 11 is introduced into a vacuum forming mold 30 and is vacuum formed into a predetermined expanded product 20. The predetermined expanded shape 20 is a predetermined product shape S as described above and expanded along the pipe direction, and the joint flanges 22 and 23 are integrally formed at both ends in the pipe direction. It is a sheet-like thing to have. The vacuum forming die 30 illustrated in FIG. 8 includes a third forming die 33 serving as an intermediate die in addition to a first forming die 31 that is a concave die and a second molding die 32 that is a convex die (plug die). As shown in the figure, the softened sheet material 11 is shaped into a predetermined expanded product 20 by the forming dies 31, 32, 33. In addition, at the time of this shaping | molding, the surface of the sheet | seat material 11 becomes a precise | minute surface by contacting a mold surface, and rigidity is provided to a molded article.

  As defined in the invention of claim 4, in the expanded product forming step, the thin portion 26 or the groove portion 27 or the bellows portion 25 for bending is integrated into the sheet material 11 as necessary by vacuum forming. It is formed. Although not shown in the drawing, on the mold surfaces of the respective molds 31, 32, 33, necessary mold surface portions for the thin wall portion 26, the groove portion 27, or the bellows portion 25 are formed. Reference numeral 37 in the figure denotes a vacuum suction unit.

  After completion of the shaping, the expanded product 20 is obtained by natural cooling or forcibly cooling and curing by a known method, and trimming if necessary. Thereafter, the widened object 20 is formed into a predetermined product shape by integrally joining the joint flanges 22 and 23 at its ends. In this embodiment, the joining is heat-sealed using an adhesive made of a thermoplastic resin.

  After the joining or simultaneously with the joining, a finishing process is performed as necessary to obtain the foamed tubular product 10. The thickness of the sheet material 11 of the obtained foamed tubular product 10 is slightly thinner than that before molding. The thickness of the sheet material 11 before forming used in the examples is about 2 to 8 mm, but when this is vacuum formed, the thickness becomes about 1.5 to 7 mm.

  In addition, although the foamed tubular product which concerns on this invention demonstrated using the air duct for motor vehicles in the Example, it is not limited to this. It is also possible to freely form the attachment portion at the end of the foamed tubular product. In addition, the configuration and the like can be changed as appropriate without departing from the spirit of the present invention.

1 is a perspective view of a foamed tubular product according to an embodiment of the present invention. It is a perspective view of the expansion-like thing of the foaming tubular product of FIG. It is a perspective view which shows the other example of an expansion-like thing. It is sectional drawing of an expanded-like thing. It is sectional drawing of another expansion-like thing. It is sectional drawing of another expansion-like thing. It is a partial expanded sectional view of a sheet material. It is a schematic sectional drawing showing the vacuum forming process of an expanded-form thing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Foamed tubular product 11 Sheet material 20, 20A, 20B Expanded material 22, 23 Joint flange part 25 Bellows part 26 Thin part 27 Groove part 30 Vacuum forming die

Claims (4)

  It is made of a sheet material mainly composed of synthetic resin foam, and has a shape in which a predetermined product shape is expanded along the pipe direction by vacuum forming, and joint joints are integrated at both ends in the pipe direction. The expanded tubular product is formed by joining the expanded product in the joint joint portion to a predetermined product shape.   The foamed tubular product according to claim 1, wherein a thin-walled portion, a groove portion, or a bellows portion is integrally formed by vacuum forming on the bent portion of the expanded product. Preheating the sheet material mainly composed of a synthetic resin foam to a formable temperature;
The sheet material is formed into an expanded product having a shape obtained by expanding a predetermined product shape along the tube direction by vacuum forming and having joint joints integrally at both ends in the tube direction. And the process of
A method for producing a foamed tubular product, comprising the step of joining joint portions of the expanded product.   The manufacturing method of the foaming tubular product of Claim 3 which forms the thin part or groove | channel part or a bellows part for bending in the said sheet | seat material by vacuum forming in the said expansion-form thing formation process.

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