Patent Publication Number: US-2019193385-A1

Title: Method for producing sheet material, and method for mixing mixed raw material

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a National Stage Entry application of PCT International Application No. PCT/JP2016/077576, filed on Sep. 16, 2016, the entire contents of which are hereby incorporated by reference. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present invention relates to a method for manufacturing a sheet member and a method for mixing a mixed material. 
     2. Description of the Background 
     Conventionally, automotive interior parts such as door trims, luggage trims, or rear parcel shelfs are manufactured through the press forming process performed on a sheet member being a composite material, which is a lamination of a sheet base member composed of polypropylene resin or the like and a nonwoven fabric formed of polyester fibers or the like as a surface member (see Japanese Patent Application Publication No. H11-010717 (hereinafter referred to as “Patent literature 1”) and Japanese Patent Application Publication No, 2002-292664 (hereinafter referred to as “Patent Literature 2”)). 
     In the press forming process and its preceding and subsequent processes, the sheet member is trimmed into a predetermined shape and any openings are punched out of the sheet member. Therefore, waste members are produced in these processes. The ratio of the waste members can reach about 50% in serious cases. 
     Accordingly, there have been made attempts to recycle (reuse) the waste members. Here, the sheet member is made up of the base member and the surface member composed of different resin materials. Recycling just the base member necessitates a removal or separation work and, consequently, takes much time and costs. 
     BRIEF SUMMARY 
     On the other hand, it has also been contemplated to recycle the sheet member without separating into the base member and the surface member. In this case, waste members produced from a sheet member containing any recycled waste members are again recycled. Therefore, the ratio between the materials of the sheet member (or the base member) changes after every recycling, inviting a loss of a desired physical property. 
     The present invention has been made in view of such circumstances, and an object thereof is to provide a method for manufacturing a sheet member whose physical property little changes despite use of a composite material being recycled. 
     Other object of the present invention is to provide a method for manufacturing a mixed material whose physical property little changes despite use of a mixed material being recycled. 
     The present invention has been made in order to achieve the object stated above. (1) One aspect of the present invention is a method for manufacturing a sheet member having a lamination of a first sheet and a second sheet. The method includes: a first step of extruding, in a sheet-like manner, a first material containing a sheet member as a recycle material, to form a first sheet; and a second step of laminating a second sheet composed of a second material and the first sheet obtained by the extruding. In the first step, the recycle material is mixed into the first material by a recycle ratio of r wt % to the first material. In the second step of laminating the second sheet and the first sheet, a ratio of the second sheet to the sheet member is set to be [A·(100−r)]×10 −4  wt %, where A is a content of the second material to the sheet member by weight percent after the first step and the second step are repeatedly performed infinitely often. 
     (2) Other aspect of the present invention is a method for manufacturing a mixed material. The method includes mixing a first material and a third material with each other to obtain a mixed material. The first material contains a recycle material being the mixed material by a recycle ratio of r wt % to the first material. The third material contains the second material by X wt %. In the mixing, a ratio of the third material to the mixed material is set to be [A·X·(100−r)]×10 −6  wt %, where A is a content of the second material to the mixed material by weight percent after the first material and the third material are mixed with each other infinitely often. 
     The present invention provides the method for manufacturing a sheet member whose physical property little changes despite use of a composite material being recycled. 
     Further, the present invention provides the method for manufacturing a mixed material whose physical property little changes despite use of a mixed material being recycled. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic diagram illustrating processes of manufacturing an interior part. 
         FIG. 2  is a cross-sectional view showing the structure of a sheet member. 
         FIG. 3  is a schematic diagram illustrating a method for manufacturing a sheet member according to a first embodiment of the present invention. 
         FIG. 4  is a graph showing the result of evaluating the physical property of the sheet member. 
         FIG. 5  is a schematic diagram illustrating a method for manufacturing a mixed material according to second embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     In the following, with reference to the drawings, a detailed description will be given of modes for carrying out the present invention (hereinafter referred to as “embodiments”). 
     Interior Part 
       FIG. 1  is a schematic diagram illustrating processes of manufacturing an interior part. 
     Normally, a vehicle&#39;s cabin includes an interior part  1 , such as a door trim, a luggage trim, or a rear parcel shelf The interior part  1  is obtained from a sheet member  30  being a lamination of a first sheet  10  and a second sheet  20 . The sheet member  30  undergoes works with a press forming machine  240  including a die assembly made up of an upper die and a lower die. Conforming to the shape of the die assembly, the sheet member  30  is shaped into any shape of the interior part  1  including recesses and protrusions, holes or openings. 
     During, before and after the press forming process with the press forming machine  240 , from the original sheet being the sheet member  30 , portions that do not serve as the interior part  1  are produced as waste members  2 . Recycling (reusing) the waste members  2 , a new sheet member  30  is manufactured. 
     Sheet Member 
       FIG. 2  is a cross-sectional view showing the structure of the sheet member. 
     The sheet member  30  is a composite material being a lamination of a first sheet  10  as a sheet base member and a second sheet  20  as a surface member, The thickness of the first sheet  10  falls within a range of about 0.5 mm to 6 mm inclusive, and the thickness of the second sheet  20  falls within a range of about 0.5 mm to 2 mm inclusive. Therefore, the thickness of the sheet member  30  falls within a range of about 1 mm to 8 mm inclusive. The lamination ratio by weight between the first sheet  10  and the second sheet  20  will be described later. 
     The first sheet  10  is formed of a first material  11  extruded sheet-like. The first material LI forming the first sheet  10  is composed of a first component  12  in the initial state, and contains an additive  13  or the like as necessary. When the waste members  2  are to be recycled, the waste members  2  are added to the first material  11  as a recycle material  31 . 
     Here, the first component  12  is, for example, polypropylene (PP) resin. Further, the additive  13  may be talc which facilitates moldability and releasability. 
     The second sheet  20  is formed as a nonwoven fabric sheet of fibers composed of a second material  21  The second material  21  forming the second sheet  20  is, for example, polyester (polyethylene terephthalate, PET) resin. 
     Apparatus and Method for Manufacturing Sheet Member 
       FIG. 3  is a schematic diagram illustrating a method for manufacturing the sheet member of the present embodiment. 
     A manufacturing apparatus  200  for manufacturing the sheet member  30  includes by an extrusion machine  210 , a laminating machine  220 , and a cutting machine  230 . 
     The extrusion machine  210  used in a first step S 1  of forming the first sheet  10  includes an extrusion barrel  211 , and a T-die  212  provided at the exit end of the extrusion barrel  211 . 
     Provided on the extrusion barrel  211  is a supply hopper  213  from which an extrusion material, that is, the first material  11 , is supplied. The extrusion barrel  11  includes therein a not-shown screw for extruding the first material  11 . Further, the extrusion barrel  211  also includes a not-shown heater for heating and melting the first material  11 . 
     The supplied first material  11  is previously fined into chips or pellets and shuffled. When the first material  11  contains the waste members  2  of the sheet member  30  as the recycle material  31  also, the first material  11  is similarly fined and shuffled. 
     The T-die  212  spreads the first material  11  extruded from the extrusion barrel  211  in the width direction thereby shaping the first material  11  sheet-like, and discharges the shaped first material  11  from a slit. In this manner, the extrusion machine  210  extrudes the first material  11  sheet-like, thereby forming the first sheet  10 . 
     Next, a laminating machine  220  used in a second step S 2  of laminating the first sheet  10  and the second sheet  20  together includes a pair of laminating rollers  221 . 
     The laminating machine  220  sets the first sheet  10  and the second sheet  20  between the pair of laminating rollers  221  and produces a laminate consisting of the first sheet  10  and the second sheet  20 . Note that, the laminating rollers  221  are not limited to an upper and lower pair, and may be a set of three rollers consisting of an upper roller, an intermediate roller, and a lower roller. In this case, the first sheet  10  is set between the intermediate and lower laminating rollers d the second sheet  20  is fed between the upper and intermediate laminating rollers  221  from the right side in the drawing so that the first sheet  10  and the second sheet  20  are set together between the upper and intermediate laminating rollers  221 . 
     In this manner, the laminating machine  220  laminates the first sheet  10  and the second sheet  20  together, thereby forming the sheet member  30 . Here, the first sheet  10  and the second sheet  20  are laminated together constantly at a preset certain lamination ratio by weight. 
     The cutting machine  230  has upper and lower cutting blades, and cuts the sheet member  30  by a predetermined length. Thus, the sheet member  30  becomes a predetermined-length original sheet for the interior part  1 . 
     Lamination Ratio by Weight of First Sheet and Second Sheet 
     In the first step S 1 , the recycle material  31  is contained in the first material  11  by a recycle ratio of r wt % (hereinafter, “wt” is omitted and simply referred to as “%”) to the first material  11 . While the recycle ratio r differs by the type of the interior part  1  or the like, the recycle ratio r falls within a range of about 20% to 60% inclusive. 
     Here, when the content of the second material  21  to the sheet member  30  at the shipment of the shaped sheet member  30  as the interior part  1  is A%, that is, when the content of the second material  21  to the sheet member  30  after the first step S 1  and the second step S 2  are repeatedly performed infinitely often is A%, in the second step S 2  of laminating the first sheet  10  and the second sheet  20  together, the second sheet  20  is set to have a ratio of [A·(100−r)]×10 −4 % to the sheet member  30 . 
     In a general method for manufacturing the sheet member  30 , firstly the lamination ratio by weight between the first sheet  10  and the second sheet  20  is set. Here, as the waste members  2  of the sheet member  30  are repeatedly recycled with the firstly determined lamination ratio by weight, the content A of the second material  21  gradually rises, and exceeds the predetermined content. Thus, the sheet member  30  whose physical property deviates from the designed physical property is manufactured. 
     For example, when the sheet member  30  is obtained as a lamination at a lamination ratio by weight of 90:10 between the first sheet  10  and the second sheet  20  with a recycle ratio r of 50%, theoretically, the ratio of the second material  21  rises to 20% after the first step S 1  and the second step S 2  are repeatedly performed infinitely often, doubling from the initial state. 
     When the physical property of the sheet member  30  deviates d poor values, the interior part  1  cannot be commercially provided. Conversely, when the physical property of the sheet member  30  deviates toward improving values, while the interior part  1  can be commercially provided, the improving values mean that the second material  21  is excessively used by the deviation, and the material cost is wasteful. 
     In view of the foregoing, in the method for manufacturing the sheet member  30  according to the embodiment, as described above, the initial lamination ratio by weight between the first sheet  10  and the second sheet  20  is reversely calculated from the final state and set. 
     By virtue of the lamination ratio by weight between the first sheet  10  and the second sheet  20  being set in this manner, the content of the second material  21  gradually rises toward the predetermined content. Thus, the sheet member  30  having the designed physical property is manufactured. 
     For example, when the content A of the second material  21  in the interior part  1  of the shipment quality is set to 15% with a recycle ratio r of 50%, theoretically, the first laminating for obtaining the sheet member  30  should be performed by a lamination ratio by weight of 92.5:7.5 between the first sheet  10  and the second sheet  20 . 
     Then, a content Al of the second material  21  to the sheet member  30  after the first recycle is as follows: 
         A 1=7.5+(7.5/100)×(92.5)×(50/100)=10.97%
 
     A content A 2  of the second material  21  to the sheet member  30  after the second recycle is as follows: 
         A 2=7.5+(7.5/100)×(92.5)×(50/100) 1 +(7.5/100)×(92.5)×(50/100) 2 =12.70%
 
     A content An of the second material  21  to the sheet member  30  after the n-th recycle is as follows: 
         An =7.5+(7.5/100)×(50/100) 1 ×(92.5)+(7.5/100)×(50/100) 2 ×(92.5)+ . . . +(7.5/100)×(50/100) n ×(92.5)%
 
     Here, when n is infinite ∞, a content A∞ of the second material  21  to the sheet member  30  is as follows: 
         A∞= 7.5/[1−(50/100)]=15.00%
 
     Note that, the values derived are as follows: A3=13.57%, A4=14.00%, A5=14.22%, A6=14.33%, A7=14.38%, A8=14.41%. The value of A6 being derived after the sixth recycle corresponds to about 96% of the value of A∞. Thereafter, since the content An of the second material  21  of the sheet member  30  asymptotically approaches 15.00%, the ultimate variation of the content is about 4%. 
     Physical Property of Sheet M 
       FIG. 4  is a graph showing the result of evaluating the physical property of the sheet member. 
     In order to evaluate the physical property of the sheet member  30 , the bending test was performed as to the longitudinal direction (the extrusion direction, the machine direction (MD)) and the width direction (the transverse direction (TD)), and the bending modulus was obtained. 
     The test result demonstrates that the bending modulus of the sheet member  30  settles after around the sixth and seventh recycles, without a large difference between the sixth and seventh recycles. This can be explained as follows. As described above, after the sixth or seventh recycle, the content A 6 , A 7  of the second material  21  to the sheet member  30  is about 96% of the value of A∞, where variations in the content of the second material  21  becomes small. Theoretically, the content A of the second material  21  to the sheet member  30  becomes about 96% of the value of A∞ after the fourth recycle. 
     On the other hand, for some reasons, the bending modulus in TD reduced after the fifth recycle. Accordingly, to be on the safe side, the interior part  1  made of the sheet member  30  after the sixth or seventh recycle should be commercially provided. 
     As has been described above, the method for manufacturing the sheet member  30  according to the first embodiment is a method for rnanufacturing a sheet member  30  being a lamination of a first sheet  10  and a second sheet  20 . The method includes: a first step S 1  of extruding, in a sheet-like manner, a first material  11  containing a sheet member  30  as a recycle material  31 , to form a first sheet  10 ; and a second step S 2  of laminating a second sheet  20  composed of a second material  21  and the first sheet  10  obtained by the extruding. In the first step S 1 , the recycle material  31  is mixed into the first material  11  by a recycle ratio of r wt % to the first material  11 . When a content of the second material  21  to the sheet member  30  after the first step Si and the second step S 2  are repeatedly performed infinitely often is A wt %, in the second step S 2  of laminating the second sheet  20  and the first sheet  10 , the second sheet  20  is set to have a ratio of [A·(100−r)]×10 −4  wt % to the sheet member  30 . 
     Thus, when the first sheet  10  is formed using the recycle material  31  being the waste members  2  of the sheet member  30  being a lamination of the first sheet  10  and the second sheet  20 , the content A of the second material  21  to the sheet member  30  still assumes a predetermined value. Therefore, the sheet member  30  having the physical property true to design is manufactured. 
     Further, the recycling the waste members  2  of the sheet member  30  eliminates any waste object resulting from the manufacture of the interior part  1 , Still further, the recycling the waste members  2  of the sheet member  30  also eliminates the necessity of removing or separating the first sheet  10  and the second sheet  20  from each other and, consequently, also eliminates any processes, apparatuses and manpower that would otherwise be required. 
     Subsequently, a description will be given of a second embodiment. 
       FIG. 5  is a schematic diagram illustrating a method for manufacturing a mixed material according to a second embodiment of the present invention. 
     In the first embodiment, the recycle technique is applied to the method for manufacturing a sheet member. On the other hand, in the second embodiment, the recycle technique is applied to a method for manufacturing a mixed material. 
     A mixed material  140  is manufactured by mixing a first material  111  and a third material  131  containing a second material  121  with each other using an agitating machine  300 . 
     The first material.  111 , the second material  121 , and the third material  131  may each be a liquid or a powder. Alternatively, they may each be a solid which exhibits flowability by being melted, for example, the resin materials described in the first embodiment. Further, the type of the first material  111 , the second material  121 , and the third material  131  is not particularly limited, so long as they are evenly dispersed as, for example, a mixture of liquids, or a mixture of a liquid and a powder. For example, the first material  111 , the second material  121 , and the third material  131  may each be a liquid drug, a coating liquid, food, a composite resin or the like. 
     Note that, it is defined that the third material  131  also contains a third component  132 , and contains the second material  121  being different from the third component  132 . by X wt % (hereinafter “wt” is omitted, and simply referred to as “%”). 
     The mixed material  140  is supplied to production of any product after the mixing. The remainder of the mixed material  140  is again mixed with the first material  111  as a recycle material  141 , by a recycle ratio of r% to the first material  111 . While not particularly limited, the recycle ratio r may fall within a range of 5% to 60% inclusive. Note that, the remainder of the first material is defined as a first component  112 . 
     Here, when the content of the second material  121  to the mixed material  140  in the supplying the mixed material  140  to production is A%, that is, when the content of the second material  121  after the recycling mixing is repeatedly performed infinitely often is A%, the third material  131  set to have a ratio of [A·X·(100−r)]×10 −6 % to the mixed material  140  is mixed into the first material  111 . 
     For example, when the content A of the second material  121  in the mixed material  140  supplied to production is 20%; a recycle ratio r is 10%; and the content of the second material  121  in the third material  131  is 80%, theoretically, the first mixed material  140  should be obtained by laminating the first material  111  and the third material  131  at a ratio of 85.6:14.4, 
     As has been described above, the method for manufacturing the mixed material  140  according to the second embodiment is a method for manufacturing a mixed material  140  including a step of mixing a first material  111  and a third material  131  containing a second material  121  with each other. Into the first material  111 , a mixed material  140  as a recycle material  141  is mixed by a recycle ratio of r wt % to the first material  111 . When the content of the second material  121  is X wt %, and the content of the second material  121  to the mixed material  140  after the first material  111  and the third material  131  are mixed with each other infinitely often is A wt %, the third material  131  set to have a ratio of [A·X·(100−r)]×10 −6  wt % to the mixed material  140  is mixed into the first material  111 . 
     Thus, when the mixed material  140  being a mixture of the first material  111  and the third material  131  containing the second material  121  is supplied to production and a new mixed material  140  is prepared using the recycle material  141  being the remainder of the mixed material  140 , the content of the second material  121  to the mixed material  140  still assumes a predetermined value. Thus, the mixed material  140  having the physical property true to design is manufactured. 
     Variation 
     In the first embodiment, while the interior part  1  is manufactured using the sheet member  30 , any other part may be manufactured using the sheet member  30 . Further, the first sheet  10  may be a foamed sheet member. The second sheet  20  may be a woven fabric instead of a nonwoven fabric, or may be a sheet member or a film member. 
     The above-described mixing method according to the second embodiment may be applied to the mixing the extrusion material according to the first embodiment, to obtain a method for manufacturing the sheet member  30 . In this case, the sheet member  30  is a lamination of the first sheet  10 , and a second sheet  20  composed of a plurality of components. 
     Note that, the present invention is not limited to the above-described embodiments, and any modifications, improvements or the like within the scope of the object of the present invention are included in the present invention. 
     REFERENCE SIGNS LIST 
       1 : interior part 
       2 : waste member 
       10 : first sheet 
       11 : first material 
       12 : first component 
       13 : additive (talc) 
       20 : second sheet 
       21 : second material 
       30 : sheet member 
       31 : recycle material 
       111 : first material 
       112 : first component 
       121 : second material 
       131 : third material 
       132 : third component 
       140 : mixed material 
       141 : recycle material 
       200 : manufacturing apparatus 
       210 : extrusion machine 
       211 : extrusion barrel 
       212 : T-die 
       213 : supply hopper 
       220 : laminating machine 
       221 : laminating roller 
       230 : cutting machine 
       240 : press forming machine 
       300 : agitating machine