JP2005205445A - Method for manufacturing metallic heat insulating panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make resin foaming uniform by reducing pocket waves which are generated when performing roll forming and to obtain a metallic heat insulating panel having good appearance. <P>SOLUTION: The metallic heat insulating panel comprises a surface material, a back material and foamed resin which is charged in a space formed of the surface material and the back material. In manufacturing the metallic heat insulating panel, elongation strain is preliminarily imparted to the longitudinal direction of a coil before performing bending work by roll forming in both end parts in the width direction of one of the base stock metallic coils which become the surface member. The compressive strain which is generated when performing bending work in both end parts in the width direction is canceled by the preliminary imparted strain of elongation, so that compressive or tensile stress is not left in the whole metallic coil after working. Thus the appearance of uneven distortion on the surface after roll forming, that is after manufacturing the panel, is prevented. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to a method for manufacturing a metal heat insulating panel formed by filling and foaming a resin between a metal front plate and a back plate.

  Panels in which foam resin is sandwiched between front and back metal plates are used for fireproof and heat insulation walls such as exterior materials, interior materials, and partition materials for buildings and structures. Such panels are also used for heat insulating walls of commercial refrigerators. The heat insulating panel is integrated by engaging the male and female fitting portions formed on both side edges parallel to the longitudinal direction of the front and back metal plates. For example, fitting portions 1R and 1L are formed at both ends in the width direction of the front surface metal plate 1 (upper and lower ends in the heat insulating wall), and the fitting portions 2R and 2L meshing with the fitting portions 1R and 1L are formed on the back metal plate 2. Are formed at both ends in the width direction (FIG. 1). A heat insulating panel is configured by sandwiching the foamed resin layer 3 between the front surface metal plate 1 and the back surface metal plate 2 and engaging the fitting portions 1R, 1L and the fitting portions 2R, 2L.

For example, Patent Document 1 proposes a method for manufacturing such a metal heat insulation panel.
That is, an apparatus having an equipment configuration as shown in FIG. 2 is used. First, a metal coil S to be a surface metal plate 1 is sent from a delivery reel 11 to a roll forming machine 12, and the surface forming metal is used by the roll forming machine 12. The end portions in the width direction of the coil S are bent to form the fitting portions 1R and 1L. After the surface metal coil S on which the fitting portions 1R and 1L are formed is preheated to a predetermined temperature by the preheater 13, the liquid foamable resin R is discharged from the injector 14 onto the surface metal coil S. Since the foamable resin R is preheated with the surface metal coil S, the foaming resin R starts a foaming reaction in a short time after the start of discharge. As the foamable resin R, a nurate resin is frequently used because heat insulation performance is required.

Similarly, the metal coil B to be the back metal plate 2 is also fed from the pay-out reel 21 to the roll forming machine 22, and the roll forming machine 22 bends the widthwise end of the back metal coil B so that the surface metal Fitting portions 2R and 2L that mesh with the fitting portions 1R and 1L of the coil S are formed. The back surface metal coil B on which the fitting portions 2R and 2L are formed is preheated to a predetermined temperature by the preheater 23 and then fed into the fitting roll 31.
The front-side metal coil S and the back-side metal coil B, in which the fitting portions 2R and 2L are engaged with the fitting portions 1R and 1L at both ends in the width direction by the fitting roll 31, are a pair of upper and lower parts disposed in the heating chamber 32. Between the conveyors 33u and 33d. The front surface metal coil S and the back surface metal coil B are pressed against each other when passing between the double conveyors 33u and 33d, the foaming reaction proceeds in a pressurized and heated state, and the foamed resin layer 3 becomes the surface metal coil S, The back surface metal coils B are filled and integrated without a gap.
The metal coil S for front surface and the metal coil B for back surface sandwiching the foamed resin layer 3 are sent out from the heating chamber 32, then cut by a cutting device 34, and carried out to the next process as a heat insulating panel W having a predetermined length. Is done.

JP 2001-165388 A

By the way, both ends in the width direction of the front surface metal coil S and the back surface metal coil B are subjected to bending processing by a roll forming machine to form a fitting portion. In particular, the surface metal coil S is subjected to complicated bending. When the end of the wide metal coil is bent by a roll forming machine, unevenness as shown by P in FIG. In particular, when stainless steel or the like is used as the metal coil material, the occurrence of pocket waves may be significant.
When pocket waves occur, the foaming of the resin filled inside the panel becomes non-uniform, and not only the surface of the product panel but also the shape of the back that was almost flat after roll forming will occur. . When the metal material is plain steel with a small pocket wave by roll forming, the shape defect of the face material caused by roll forming is almost eliminated by the pressure at the time of foaming of the resin, and a well-shaped panel is obtained. However, especially when stainless steel is used as the metal coil material, the distortion of the front and back surfaces due to non-uniform foaming is conspicuous, and the product cannot be shipped as a product.
The present invention has been devised to solve such problems, and by reducing pocket waves generated during roll molding, the resin foam is made uniform, and a metal heat insulation having a good appearance is obtained. The purpose is to obtain a panel.

  In order to achieve the object, the method for manufacturing a metal heat insulating panel of the present invention manufactures a metal heat insulating panel made of a foam material filled in a surface material, a back material, and a space formed by the surface material and the back material. When performing the bending process by roll forming on the both ends in the width direction of at least one material metal coil among the material metal coils to be the face material, it is necessary to give an elongation strain in the coil longitudinal direction in advance. Features.

The inventors of the present invention have studied the generation mechanism of pocket waves generated in the face material when manufacturing a metal heat insulating panel in which a space formed by the front surface material and the back surface material is filled with foamed resin. As a result, when the width direction end of the metal coil that becomes the front surface metal plate 1 and the back surface metal plate 2 is subjected to a bending process by a roll forming machine, a longitudinal compressive strain is generated in the bent portion, and the flat portion is compressed. When the compressive stress of the flat part increases as the amount of compression of the bent part increases and exceeds the buckling limit, the surface flat part is distorted unevenly, resulting in a so-called pocket wave. I confirmed that it appeared.
As described above, when waving due to pocket waves or the like is generated in at least one of the two face materials constituting the heat insulation panel, the face materials on the front and back sides are engaged when the bent portions on both sides of the face material are engaged with each other. The interior space of the panel is not uniform, and the distribution of the foamed resin is not uniform. As a result, the pressure at which the resin foams is also unevenly distributed, and the front and back face materials are distorted.

Therefore, before applying the bending process, by applying a pre-strain of elongation in the longitudinal direction to the bent parts at both ends in the width direction of the material metal coil, the compressive strain generated when the bending process is performed is described above. By offsetting the pre-strain and preventing the entire metal coil from being subjected to compressive or tensile stress after processing, it was possible to prevent the uneven distortion from appearing on the surface after roll forming. That is, the material metal coil which becomes a wide material has a longitudinal length of a portion corresponding to a bent portion longer than a longitudinal length of a portion corresponding to a flat portion by applying pre-strain. . When this material is cold-roll formed, the longitudinal compressive strain generated in the bent portion is offset by the length in the longitudinal direction previously applied. Therefore, in the flat portion where the bending process is not performed, the acting compressive stress is suppressed below the buckling limit, and the occurrence of uneven distortion is prevented.
The amount of longitudinal strain applied to the metal coil in advance (maximum value at both ends of the coil) varies depending on the plate thickness, hardness, bent part and flat part size of the material, etc., but no prestrain is applied. 2 times the steepness of pocket waves (λ = wave height / wave pitch) generated by roll forming with JIS (Plastic Processing Technology Series 15 Straightening, page 9, 1992, Corona) A range of about 5 times is preferable.

In order to give a pre-strain of elongation in the longitudinal direction to the bent portion, a preforming roll having a different pushing amount in the axial length direction may be used so that the bent portion becomes longer in the longitudinal direction than the flat portion.
As a preforming device for making the length in the longitudinal direction different between the bent portion and the flat portion, for example, a pre-forming device as shown in FIG. What arrange | positioned the shaping | molding roll 51 is preferable. Further, when the support rolls 52 and 53 are arranged on the opposite side so as to face the preforming roll 51, the necessary portions can be reliably extended. The through-plate rolls 54 and 55 are lined with elastic bodies 54b and 55b such as urethane on the roll main bodies 54a and 55a in order to apply a predetermined tension to the traveling metal coil S. The support rolls 52 and 53 are located on the back side of the material metal coil S, and sandwich the material metal coil S in cooperation with the preforming roll 51. As the pre-forming roll 51, for example, as shown in FIG. 5, there is a minimum diameter portion 51a having the smallest diameter at the center, and a desired curved surface is formed from the minimum diameter portion 51a toward both axial end portions 51b and 51d. What is provided with the peripheral surface part 51c to be used can be used.

  The material metal coil S has a different travel distance in the width direction according to the shape of the peripheral surface of the preforming roll 51 in the process from the entrance support roll 52 to the exit support roll 53 through the preforming roll 51. In the vicinity of the end portions 51b and 51d where the pressing amount h by the preforming roll 51 is the largest, the traveling distance of the metal strip S becomes long. On the other hand, in the minimum diameter portion 51a where the pushing amount h is small, the metal strip S takes the shortest travel distance, and a large tension acts on both ends. As a result, the raw metal coil S is partially extended at both ends in the width direction due to the synergistic action of bending deformation by winding the tension and the preforming roll, and is long in the longitudinal direction between the both ends and the center. A difference is attached. This difference in length can be controlled by adjusting the vertical position of the preforming roll 51. Further, the difference in length is also controlled by changing the tension applied to the material metal coil S or by changing to a preforming roll 51 having a different crown shape. In this way, when the material metal coil S with the necessary difference in length is folded in the width direction by roll forming, a flat panel material without pocket waves is obtained.

A preforming apparatus for making the longitudinal lengths different between the bent part and the flat part is a conventional heat insulation panel production line as shown in FIG. Further, if necessary, it may be arranged between the uncoiler 21 and the roll forming machine 22, or a material provided separately from the heat insulation panel production line and provided with an appropriate pre-strain is wound around a coil. The heat insulation panel production line may be used.
Alternatively, a roll leveler having a roll bending mechanism for shape correction as shown in FIG. 6 (the above-mentioned “Plastic Processing Technology Series 15 Straightening” on pages 29 and 59) is used for roll bending that produces an edge wave. And under rolling conditions.

The material metal coil with the pre-strain stretched in the longitudinal direction at the end in the width direction is fed to the roll forming machines 12 and 22 as in the prior art, and the width direction of the metal coil by the roll forming machines 12 and 22. A bending process is given to an edge part. The subsequent steps are the same as the conventional steps.
Before roll forming, by applying pre-elongation to the end in the width direction of the material metal coil, generation of pocket waves can be suppressed in the subsequent forming process. For this reason, since the thickness of the space formed by the front surface material and the back surface material is uniform, even if the resin filled in between is foamed, the foaming is performed uniformly and a heat insulation panel with good flatness is obtained. can get. In addition, since the face material itself is extremely flat, if stainless steel is used as the material metal coil, a mirror surface can be obtained, and the design is excellent in heat insulation panel.

Comparative example;
A high corrosion-resistant chromium-based stainless steel (22Cr-0.7Mo-Nb-ULC) steel strip having a plate thickness of 0.5 mm, a plate width of 770 mm, and a backing material of 610 mm was used as the material metal coil. Without pre-straining, a 21-stage cold roll forming machine was used for the front surface material and a 6-stage cold roll forming machine was used for the back surface material to form predetermined bent portions at both ends.
Thereafter, the foamable resin R was discharged from the injector 14 onto the surface material metal coil S preheated to a predetermined temperature by the preheater 13. As the foamable resin R, a foamable nurate resin raw material liquid obtained by mixing polyisocyanate and polyol by a high pressure method was used.
At this time, the roll-formed surface material had periodic undulations having a height of about 1 mm and a period of about 500 mm (steepness λ = 0.2%). The back material had an almost flat shape.

Next, the fitting portions 2R and 2L of the back surface metal coil B are engaged with the fitting portions 1R and 1L formed at both ends in the width direction of the front surface metal coil S by the fitting roll 31, and are held at a predetermined temperature. It was sent to the heating chamber 32. In the heating chamber 32, the surface material metal coil S and the back surface material metal coil B were heated and pressurized by the double conveyors 33u and 33d to produce a heat insulating panel W having a thickness of 35 mm with the foamed resin layer 3 sandwiched therebetween.
When this heat insulating panel was placed on a flat floor, and reflected from an oblique angle from above, light was distorted, and irregular distortion was observed on both the front and back sides. The height and period of the irregularities were at a level that could not be measured by a normal method, unlike the waving due to pocket waves that occurred on the surface after roll forming.

Example;
The same material and the same size metal coil as those used in the comparative example were used.
As shown in FIG. 6, the above-mentioned metal coil used for the surface material is passed through a multi-roller leveler in which a work roll having a bending mechanism with a diameter of 36 mm, including a total of 17 on the upper side and 9 on the lower side, is incorporated. By adjusting the work roll bending amount and intermesh (rolling amount) of the leveler, the maximum value of the steepness at the end in the width direction is 0.50%, 0.70%, 0.98%, 1.05% And the coil which provided the pre-strain of the edge wave shape which is 1.10% was created. About the back material, since the shape after roll forming was favorable, no pre-strain was particularly applied in this example.
The surface material and the back surface metal coil thus prepared were passed through the metal heat insulating panel manufacturing apparatus used in the comparative example to manufacture a stainless steel heat insulating panel.

By applying the pre-strain, the pocket wave after roll forming of the surface material was greatly reduced. In addition, when the obtained heat insulation panel was placed on a flat floor, reflected from the light and observed from diagonally above, the distortion of the panel surface as observed with the heat insulation panel manufactured without pre-strain was observed on both the front and back sides. Little was observed.
However, a pre-strain exceeding 5 times the 0.2% of the steepness of the pocket wave generated in the material after roll forming under conditions without pre-strain, that is, the maximum steepness of 1.05% and In the case of applying a pre-strain of 1.10%, a slight streak pattern in the horizontal direction of the panel, which seems to be due to the effect of the pre-strain, was observed.
Therefore, in this example, good results were obtained when the pre-strain amount was in the range of 0.5% to 1.0%.
Needless to say, the appropriate range of the pre-strain varies depending on the material and thickness of the front and back materials, and the size and structure of the heat insulating panel. In accordance with each, it is preferable to confirm in advance the optimum amount of pre-strain.

  As described above, the present invention can be applied to at least both end portions in the width direction of the material metal coil of the surface material among the material metal coils to be the surface material and the back surface material of the heat insulation panel, before being subjected to bending by roll forming. By applying an elongation strain in the longitudinal direction of the coil in advance, even if the bending portion contracts by bending, it is offset by the elongation strain applied in advance, and there is a difference in length in the overall plate width direction. It was possible to obtain a bent surface material and a back surface material, and finally, a metal heat insulation panel having a good appearance was obtained without generating distortion due to pocket waves on the front and back surfaces.

Sectional drawing explaining structure of metal heat insulation panel The figure explaining the outline of the equipment structure of the apparatus which manufactures a metal heat insulation panel Illustration explaining the occurrence of pocket waves The figure explaining an example of the method of giving the pre-strain of elongation to the width direction edge part Diagram showing an example of the shape of a preforming roll Diagram explaining the roll arrangement status of multi-roller leveler

Claims (1)

  When manufacturing a heat insulating panel made of foam resin filled with a surface material, a back material, and a space formed by the surface material and the back material, at least one material metal of the material metal coil that becomes the face material A method for producing a metal heat insulating panel, characterized in that an elongation strain is applied in the longitudinal direction of a coil in advance before being subjected to bending by roll forming at both ends in the width direction of the coil.

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