Abstract:
A foamed laminate sheet  30,  method and apparatus for making the foamed laminate sheet  30,  wherein a synthetic resin sheet  31  is formed with cuts  33  intermittently and staggeredly extending in a vertical direction and/or in a lateral direction. The synthetic resin sheet  31  with cuts  33  is extended, under tension, into a meshed sheet  32.  Then, the meshed sheet  32  may be attached to a foamed sheet  12,  to thereby produce the foamed laminate sheet  30.  In one embodiment, the extension of the synthetic resin sheet is performed by winding the synthetic resin sheet  31  with cuts  33  over a crown-shaped roller  51.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a foamed laminate sheet, and a method and apparatus used for producing the foamed laminate sheet. The foamed laminate sheet of the present invention may be used, for example, as a packaging material of products such as automotive parts.  
           [0003]    2. Description of the Related Art  
           [0004]    Conventionally, there is known a foamed laminate sheet used as a packaging material of a product and a method for producing the conventional laminate sheet as shown in FIGS. 6A to  7 F. A foamed laminate sheet  10  shown in FIGS. 6A and 6B includes a synthetic resin sheet (film)  11  (see FIG. 6C) and a foamed sheet  12  attached to the synthetic resin sheet  11  (see FIG. 6D).  
           [0005]    As shown in FIG. 6E, the synthetic resin sheet  11  and the foamed sheet  12  are thermally adhered to each other while passing between a heat roller HR 1  and a pressure roller R 1 , to thereby produce the foamed laminate sheet  10 . The reference character  11 R in FIG. 6E designates a roll of the synthetic resin sheet  11 , and  12 R designates a roll of the foamed sheet  12 .  
           [0006]    A second conventional foamed laminate sheet  20  is shown in FIGS. 7A and 7B and includes a latticed synthetic resin sheet  21  (see FIG. 7E) and the foamed sheet  12  attached to the latticed synthetic resin sheet  21  (see FIG. 7D). The foamed laminate sheet  20  is produced as follows. At first, as shown in FIGS. 7C and 7F, plural pieces of synthetic resin tape  22  and the foamed sheet  12  are thermally adhered to each other while passing between the first heat roller HR 1  and the pressure roller R 1 , so as to obtain an intermediate sheet  24 . Subsequently, synthetic resin tapes  23  being the same as the synthetic resin tapes  22 , but perpendicularly crossing with the synthetic resin tapes  22 , are attached to the intermediate sheet  24 , and then thermally adhered thereto while passing between a second heat roller HR 2  and a pressure roller R 2 .  
           [0007]    The conventional foamed laminate sheet  10  shown in FIGS. 6A and 6B is easily produced and obtained at low cost. However, since sheet  10  has a structure formed by merely adhering the synthetic resin sheet  11  to the foamed sheet  12 , there are drawbacks in that there is no air permeability of the sheet  10  and also, sheet  10  formed by this method may easily fracture. Further, because there is no air permeability, a gas generated from a plasticizer of a packed product may fill the interior of the package, contributing to discoloring of a luster on the surface of painted products.  
           [0008]    While the foamed laminate sheet  20  shown in FIGS. 7A and 7B may be air permeable and better at preventing fracture, sheet  20  is both complicated and costly to produce.  
         SUMMARY OF THE INVENTION  
         [0009]    It is an object of the invention to solve the problems mentioned above, and provide a foamed laminate sheet that has air permeability and excellent proof against the development of fracture (hereinafter referred to as “development-proof”) as well as a method and apparatus for producing the sheet that allows for obtaining low production costs.  
           [0010]    To attain the above object, according to a first aspect of the invention, there is provided a foamed laminate sheet, including a meshed sheet made of synthetic resin. The meshed sheet may be obtained by extending a synthetic resin sheet including cuts made intermittently in a substantially vertical direction and/or a substantially lateral direction. A foamed sheet is then attached to the meshed sheet. Therefore, this sheet has air permeability and excellent development-proof.  
           [0011]    The meshed sheet maybe produced by extending the synthetic resin sheet formed with intermittent cuts in a substantially vertical direction and/or a substantially lateral direction, and therefore, it is unecessary to cross plural pieces of synthetic resin tapes  22 ,  23  with each other as in the prior art shown in FIGS. 7A to  7 F. Thus, the production process is simplified, which consequently lowers the cost of production. As such, according to the foamed laminate sheet of the first aspect of the invention, packaging materials having air permeability and excellent development-proof may be obtained at low cost.  
           [0012]    According to a second aspect of the invention, there is provided a method of producing a foamed laminate sheet. The method may include the steps of forming cuts on a synthetic resin sheet that intermittently extend in a substantially vertical direction and/or a substantially lateral direction, extending the synthetic resin sheet with the cuts, to thereby form a meshed sheet, and attaching a foamed sheet to the meshed sheet so as to produce the foamed laminate sheet. Accordingly, the foamed laminate sheet having air permeability and excellent development-proof may be produced at a low cost.  
           [0013]    Further, according to a third aspect of the invention, in the foamed laminate sheet of the first aspect or the method of the second aspect, the cuts are formed in a staggered pattern. With this structure, the development-proof is improved.  
           [0014]    Moreover, according to a fourth aspect of the invention, in the method of the second aspect, the extending step is performed by winding the synthetic resin sheet over a crown-shaped roller. With this method, the meshed sheet is suitably and easily obtained, and as a result, the foamed laminate sheet may be produced at a further low cost. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    [0015]FIG. 1A is a partial plan view of a foamed laminate sheet according to an embodiment of the invention,  
         [0016]    [0016]FIG. 1B is a cross sectional view of the foamed laminate sheet,  
         [0017]    [0017]FIG. 1C is a partial plan view of a synthetic resin sheet with cuts,  
         [0018]    [0018]FIG. 1D is a partial plan view of an expanded meshed sheet, and  
         [0019]    [0019]FIG. 1E is a front view showing the production process for forming the foamed laminate sheet;  
         [0020]    [0020]FIG. 2 is a schematically perspective view showing a cutting part used in a method of the invention;  
         [0021]    [0021]FIG. 3A is a schematically perspective view of an extending part used in a method of the invention;  
         [0022]    [0022]FIG. 3B is a partially enlarged plan view of a synthetic resin sheet with cuts;  
         [0023]    [0023]FIG. 3C is a partially enlarged plan view of a meshed sheet according to an embodiment of the invention;  
         [0024]    [0024]FIG. 4A is a partial plan view of a synthetic resin sheet with cuts,  
         [0025]    [0025]FIG. 4B is a perspective view of a production process according to a method of the invention, and  
         [0026]    [0026]FIG. 4C is a partial plan view of an expanded meshed sheet;  
         [0027]    [0027]FIG. 5A is a partial plan view of a synthetic resin sheet with cuts,  
         [0028]    [0028]FIG. 5B is a partial plan view of a crown-shaped roller, and  
         [0029]    [0029]FIG. 5C is a cross sectional view taken along the lines C-C of FIG. 5B;  
         [0030]    [0030]FIGS. 6A to  6 E are schematic views explaining a conventional foamed laminate sheet and a method for producing the conventional foamed laminate sheet; and  
         [0031]    [0031]FIGS. 7A to  7 F are schematic views explaining another conventional foamed laminate sheet and a method for producing the conventional foamed laminate sheet.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0032]    A description will be given of embodiments of the invention with reference to the accompanying drawings. FIGS. 1A to  1 E are schematic views showing a foamed laminate sheet and a method for producing the foamed laminate sheet according to a first embodiment of the invention. For better understanding, FIGS. 1A to  1 E use the same numerals as FIGS. 6A to  6 E to refer to the same parts.  
         [0033]    As shown in FIGS. 1A and 1B, a foamed laminate sheet  30  according to a first embodiment of the invention includes a meshed sheet  32  (see FIG. 1D) and a foamed sheet  12  attached to the meshed sheet  32 . The meshed sheet  32  is, as described in detail later, structured by expanding a synthetic resin sheet  31  with cuts  33 a (see FIG. 1C) intermittently formed in the vertical direction. As a representative of synthetic resin sheet, there is used a polyethylene sheet, a polyvinyl chloride sheet, or the like. As a representative of foamed sheet, there is used a polyethylene foamed sheet, a polypropylene foamed sheet, or the like. The polyethylene sheet is economically superior to the polyvinyl chloride sheet. The polyethylene foamed sheet is also economically superior to the polypropylene foamed sheet.  
         [0034]    The foamed laminate sheet  30  may, as shown in FIG. 1E, be produced as follows. First, cuts  33 a may be formed on a synthetic resin sheet  11  intermittently in the vertical direction (in this case, a direction perpendicular to the sheet flowing direction) at a cut part  40 , to thereby form a sheet  31  with cuts (see FIG. 1C). Then, the sheet  31  may be extended at an extending part  50  so as to form the meshed sheet  32  (see FIG. 1D), and further the meshed sheet  32  may be attached to the foamed sheet  12  at an attaching part  60 .  
         [0035]    As shown in FIG. 2, the cut part  40  may include a cutter roller  41  and a receiving roller  42 . The cutter roller  41  may be structured by, for example, providing blades  41 b which correspond to the cuts  33 a to be formed on a surface of a metallic roller  41 a. The receiving roller  42  may be structured by, for example, a rubber roller. Accordingly, the cuts  33 a may be formed bypassing the synthetic resin sheet  11  between the cutter roller  41  and the receiving roller  42 , so that the sheet  31  with cuts (see FIG. 1C and FIG. 3B) is produced. In the first embodiment of the invention, the cuts  33 a are formed in a staggered pattern as shown in FIG. 1C and FIG. 3B. Of course, other materials for the rollers and differing patterns of the cuts may be used without departing from the scope of the invention.  
         [0036]    As shown in FIG. 3A, the extending part  50  may comprise a crown-shaped roller  51 . In FIG. 3A, the arrangement of the roller  51  is changed from that of FIG. 1E for explanatory purposes.  
         [0037]    The crown roller  51  may be preferably structured with a material (for example, a metal) that obtains a superior sliding property for the sheet  31  ( 11 ). For example, when the sheet  31  with cuts as seen in FIG. 3A is wounded over the crown-shaped roller  51 , tension T is applied to the sheet  31  as seen in FIG. 3C. Thus, tension T 1  is also applied to the cuts  33 a, whereby the cuts  33 a are expanded to form the meshed sheet  32 .  
         [0038]    The attaching part  60  includes the heat roller HR 1  and the pressure roller R 1  as well as the conventional one.  
         [0039]    The meshed sheet  32  and the foamed sheet  12  are passed between the heat roller HR 1  and the pressure roller R 1  and thermally adhered to each other, whereby the foamed laminate sheet  30  is produced. Of course, other ways of adhering the meshed sheet  32  and the foamed sheet  12  may be used.  
         [0040]    Therefore, according to the foamed laminate sheet and the producing method of the first embodiment, the following working effects are available. Specifically, the foamed laminate sheet  30  according to the first embodiment includes the meshed sheet  32  fabricated by extending the synthetic resin sheet  31  with cuts  33 a formed intermittently in the vertical direction, and the foamed sheet  12  attached to the meshed sheet  32 . Therefore, this sheet has air permeability and excellent development-proof.  
         [0041]    Further, the meshed sheet is obtained by only expanding the synthetic resin sheet with cuts formed intermittently in the vertical direction. Accordingly, it is no longer necessary to cross plural pieces of synthetic resin tapes  22 ,  23  with each other as the prior art shown in FIG. 7. Therefore, the production process is simplified and consequently the products are available at low cost. As such, the foamed laminate sheet  30 , a packaging material having air permeability and excellent development-proof may be obtained at low cost.  
         [0042]    [0042]FIGS. 4A to  4 C are schematic views showing a foamed laminate sheet and a method for producing the foamed laminate sheet according to a second embodiment of the invention. For better understanding, FIGS. 4A to  4 C use the same numerals as FIGS. 1A to  1 E to refer to the same parts.  
         [0043]    Referring to FIG. 4A, the second embodiment differs from the first embodiment in that the cuts  33  comprise cuts  33 a in the vertical direction and cuts  33 b in the lateral direction which are formed in a staggered pattern on the synthetic resin sheet  11 , and other points are not changed. The cutter roller  41  is formed with the blades corresponding to the cuts  33 .  
         [0044]    When the sheet  31  with cuts  33  is wound over the crown-shaped roller  51  as shown in FIG. 4B, tension T 1  in the lateral direction and tension T 2  in the vertical direction are applied to the sheet  31 , as seen in FIG. 4C, whereby the cuts  33  are expanded to form the meshed sheet  32 .  
         [0045]    As described above, when the cuts  33  are made in the lateral direction, the width W 2  of the meshed sheet  32  has about twice of the W 1  of the synthetic resin sheet  11 .  
         [0046]    According to this embodiment, the method of producing the foamed laminate sheet  30  makes cuts  33 a intermittently in the vertical direction on the synthetic resin sheet  11  to form the synthetic resin sheet  31  with cuts, extends the sheet  31  to form the meshed sheet  32 , and attaches the foamed sheet  12  to the meshed sheet  32 , to thereby obtain the foamed laminate sheet  30 .  
         [0047]    According to this producing method, the foamed laminate sheet  30  having air permeability and excellent development-proof may be obtained at low cost. Also, since the cuts  33 a are staggeredly formed in the foamed laminate sheet  30 , the development-proof is improved.  
         [0048]    The sheet  31  with cuts may be extended by winding the sheet  31  over the crown-shaped roller, so as to obtain the meshed sheet  32  suitably and easily. As a result, the foamed laminate sheet  30  may be produced at further low cost.  
         [0049]    [0049]FIGS. 5A to  5 C are schematic views showing a foamed laminate sheet and a method for producing the foamed laminate sheet according to a third embodiment of the invention. For better understanding, FIGS. 5A to  5 C use the same numerals as FIGS. 1A to  1 E to refer to the same parts.  
         [0050]    The third embodiment is different from the first embodiment in that, as shown in FIG. 5A, the cuts  33  having the cuts  33 a in the vertical direction and cuts  33 b in the lateral direction are formed in a staggered pattern on the synthetic resin sheet  11 , and other points are not changed. The cutter roller  41  is formed with blades corresponding to the cuts  33 .  
         [0051]    Further, as shown in FIGS. 5B and 5C, the crown-shaped roller  51  includes ring-shaped convexes  52  at positions corresponding to the cuts  33 b in the lateral direction of the synthetic resin sheet  11  (the sheet flowing direction).  
         [0052]    When the sheet  31  with cuts  33  is wound over the crown-shaped roller  51  shown in FIGS. 5B and 5C, the cuts  33 b in the lateral direction are suitably expanded. Also in the third embodiment, the working effects similar to those of the first embodiment are provided.  
         [0053]    While only certain embodiments of the invention have been specifically described herein, it will apparent that numerous modifications may be made thereto without departing from the spirit and scope of the invention. As an example, intermittent cuts may be made only in the lateral direction. Further, the cuts may be made with a punch having a long hole instead of the blade.