Abstract:
The object of the present invention is to provide a method for manufacturing a product of thermoplastic resin and/or thermoplastic elastomer with materials of high recycle capability, preventing the productivity drop and the cost increase as well as the damage caused by the contact between semi-finished products and a drawing machine. A plurality of semi-finished moles and a drawing element are molded integrally by an extruder. The semi-finished moles are separated from the drawing element by cutting. The semi-finished moles separated from the drawing element are cut in accordance with a given length to produce a mole.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to a method for manufacturing a product of thermoplastic resin and/or thermoplastic elastomer, which is used for interior and exterior moles, and door and body seals.  
         BACKGROUND OF THE INVENTION  
         [0002]    The parts manufactured by extrusion such as interior and exterior moles and door and body seals include; a door mole, an inner weather strip, a drip mole, a window mole, a roof mole, an opening trim, an opening seal, a trunk lid seal, a tail gate seal, a door seal and a run channel. As an example, the part such as shown in FIG. 12 has been manufactured conventionally. A mole  110  has been manufactured with a metallic core  111  made of aluminum alloy or stainless steel, to which a seal  112  made of a PVC material of thermoplastic resin or an EPDM material of rubber or thermoplastic elastomer and a decorative surface  113  are integrally molded by extrusion molding. An elastomer is an elastic resin like rubber and a thermoplastic elastomer is a rubber-like molding material which can be molded by the remelt treatment. And a thermoplastic resin is an inelastic resin which can be molded by the remelt treatment.  
           [0003]    The process for manufacturing the mold mentioned above is shown in FIG. 13. At an extrusion step S 10 , a metallic core material M, a lip material L and a decorative material D, which are composed of a PVC material of thermoplastic resin, are supplied to an extruder  120  where an extrusion molding is performed. A semi-finished mole  115  is manufactured and is supplied to a cooling step S 20 . At the cooling step S 20 , the semi-finished mole  115  is cooled down passing through a cooling chamber  121 . At a drawing step S 30  subsequent to the cooling step S 20 , the semi-finished mole  115  is drawn with the rotation of a drawing machine  122 . Drawing by the drawing machine  122  gives the drawing force to the semi-finished mole  115  at the cooling step S 20 .  
           [0004]    The semi-finished mole  115  is supplied to a dimension measurement step S 40  from the drawing step S 30  and measured up. And at a cutting step S 50 , the semi-finished mole is cut in accordance with the required length measured at the dimension measurement step S 40  by a cutting machine  124  to produce a mole  110 , which is stored in a container  125 .  
           [0005]    The mole  110  including the metallic core  111  made of a metal, to which the seal  112  and the decorative surface  113  made of the thermoplastic resin are integrally molded, is difficult to be recycled, thereby giving rise to environmental pollution caused by poisonous gasses when it is incinerated. The part made of olefinic material thoroughly has been recently introduced, in which a core is also made of thermoplastic resin, so that the core can be recycled. This type of part can be manufactured by the same process as that shown in FIG. 13.  
           [0006]    However, manufacturing of the thorough olefinic parts has been suffered from the following problems.  
           [0007]    The rupture, the surface waviness and the rough surface of the core will possibly occur if the part of thorough olefinic material is manufactured under the same extrusion speed as that of the part with a metallic core. In order to prevent the problems such as surface waviness, the extrusion speed must be slowed down to approximately one fifth of that applied to the manufacturing of the part with a metallic core. It will lower the productivity, thereby giving rise to the remarkable cost increase. If the parallel operation with plural extruders to compensate the productivity drop is introduced, more drawing machines are required for that.  
           [0008]    The drawing machine has been possibly caused damage to the seal or the decorative surface of the mole since the drawing machine requires interposing the mole for drawing. It is possible to lower the interposing force of the drawing machine in order not to cause damage on the seal or the decorative surface of the mole, though another problem could occur that the slipping due to the resultant decrease in the drawing force renders the drawing machine inoperable.  
         SUMMARY OF THE INVENTION  
         [0009]    The object of the present invention to assess the problems is to provide a method for manufacturing a product of thermoplastic resin and/or thermoplastic elastomer with materials of high recycle capability, preventing the productivity drop and the cost increase as well as the damage caused by the contact between the semi-finished products and the drawing machine.  
           [0010]    The invention to assess the problems described above provides a method for manufacturing a product of thermoplastic resin or thermoplastic elastomer, or a hybrid product of thermoplastic resin and thermoplastic elastomer, the method comprising the steps of: molding integrally a plurality of semi-finished products and a drawing element by extrusion, which comprise thermoplastic resin or thermoplastic elastomer, or a hybrid of thermoplastic resin and thermoplastic elastomer; separating the plurality of semi-finished products from the drawing element by cutting in a drawing direction; drawing the drawing element separated from the plurality of semi-finished products by a drawing machine, thereby continuing to draw the plurality of semi-finished products and the drawing element which are before separation; and cutting the plurality of semi-finished products at a given length from which the drawing element has been separated.  
           [0011]    The invention according to claim 1 provides a method of manufacturing a product by molding the plural semi-finished products and the drawing element integrally, thereby obviating the productivity drop even if the extrusion speed is lowered.  
           [0012]    When the semi-finished products are drawn at the previous stage of manufacturing the finished product, the drawing element, which is molded integrally with the semi-finished product, is drawn by the drawing machine. The semi-finished products are not required to be in contact with the drawing machine, which will obviate the damage caused by the contact with the drawing machine.  
           [0013]    The invention according to claim 2 provides the method for manufacturing a product of thermoplastic resin or thermoplastic elastomer, or a hybrid product of thermoplastic resin and thermoplastic elastomer according to claim 1, wherein the plurality of semi-finished products and the drawing element comprise an olefinic material.  
           [0014]    The invention according to claim 2 employs the olefinic materials—desirable for recycling—both for the semi-finished products and the drawing element. Therefore, the recycling of the product can be conducted properly when it is scrapped. Also, the drawing element can be reused for the material of extrusion molding repeatedly not scrapped.  
           [0015]    The invention according to claim 3 (or 4) provides the method for manufacturing a product of thermoplastic resin or thermoplastic elastomer, or a hybrid product of thermoplastic resin and thermoplastic elastomer according to claim 1 (or 2), wherein the thickness of connecting elements for connecting the plurality of semi-finished products and the drawing element is from no less than 0.5 mm to no more than 10 mm.  
           [0016]    If the thickness of the connecting elements between the semi-finished products and the drawing element is less than 0.5 mm, the semi-finished products and the drawing element tend to separate accidentally. On the contrary, if it is more than 10 mm, it may possibly be time-consuming to separate the semi-finished products from the drawing element. It is the reason why the invention according to claim 3 specifies the range of no less than 0.5 mm to no more than 10 mm for the thickness of the connecting elements. This range of thickness will prevent the accidental separation of the product material from the drawing element and render the cutting easier at the separation step.  
           [0017]    The invention according to claim 5, (6, 7 or 8) provides the method for manufacturing a product of thermoplastic resin or thermoplastic elastomer, or a hybrid product of thermoplastic resin and thermoplastic elastomer according to claim 1, (2, 3 or 4), wherein the plurality of semi-finished products are oriented facing in a common direction.  
           [0018]    When the product has a surface sliding on the glass, hair transplanting is sometimes made on it. In case the sliding surface where the hair transplanting is made is on one surface of the product, the semi-finished products need to be oriented in a given direction. The invention according to claims 5 through 8 eliminates a step to rotate the semi-finished products to align the sliding surfaces, since the semi-finished products face in a common direction. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]    [0019]FIG. 1 is a cross sectional view showing a product of thermoplastic resin and thermoplastic elastomer according to the present invention.  
         [0020]    [0020]FIG. 2 is a cross sectional view showing an extrusion molded part.  
         [0021]    [0021]FIG. 3 is a process flow diagram showing the steps of manufacturing moles from an extrusion molded part.  
         [0022]    [0022]FIG. 4 is a cross sectional view of the extrusion molded part according to the second embodiment.  
         [0023]    [0023]FIG. 5 is a cross sectional view of the extrusion molded part according to the third embodiment.  
         [0024]    [0024]FIG. 6 is a cross sectional view of the extrusion molded part according to the fourth embodiment.  
         [0025]    [0025]FIG. 7 is a cross sectional view of the extrusion molded part according to the fifth embodiment.  
         [0026]    [0026]FIG. 8 is a cross sectional view of the extrusion molded part according to the sixth embodiment.  
         [0027]    [0027]FIG. 9 is a cross sectional view of the extrusion molded part according to the seventh embodiment.  
         [0028]    [0028]FIG. 10 is a cross sectional view of the extrusion molded part according to the eighth embodiment.  
         [0029]    [0029]FIG. 11A is an enlarged view of the connecting element shown in FIG. 2.  
         [0030]    [0030]FIG. 11B is an enlarged view showing connecting elements with reduced portions.  
         [0031]    [0031]FIG. 12 is a cross sectional view showing the mole according to the prior art.  
         [0032]    [0032]FIG. 13 is a process flow diagram illustrating the manufacturing of the mole according to the prior art. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0033]    The embodiment of the present invention will now be described referring to the accompanying drawings.  
         [0034]    [0034]FIG. 1 is a sectional view showing a mole of thermoplastic resin and thermoplastic elastomer according to the present invention.  
         [0035]    The method for manufacturing a mole  1  such as a door mole, which has the cross section shown in FIG. 1, will be described. The mole  1  is a long product, which is cut out from a semi-finished mole manufactured by extrusion, including a core  2 , a lip  3  and a decorative surface  4 . The core  2  is made of PP (polypropylene) of thermoplastic resin, which has some degree of hardness and stiffness. On the other hand the lip  3  and the decorative surface  4  are made of TPO (thermo plasticelastomer olefin) resin of thermoplastic elastomer, which have elasticity. The core  2 , the lip  3  and the decorative surface  4  are all made of the olefinic materials of thermoplastic resins, which are desirable in terms of recycling.  
         [0036]    The mole  1  shown in FIG. 1 is cut out from the long semi-finished mole manufactured by extrusion. In this embodiment, the four of the same shape semi-finished moles are manufactured simultaneously. The plural semi-finished moles are integrally molded connected to a drawing element with respective connecting elements (the whole part including the semi-finished moles connected to the drawing element with the connecting elements hereinafter referred to as extrusion molded part).  
         [0037]    Before the description of the manufacturing process, an example of the position of the semi-finished moles and the drawing element of an extrusion molded part will be described referring to FIG. 2. An extrusion molded part  10  has four semi-finished moles  11 - 14 , which are simultaneously extruded. As shown in FIG. 2, the four semi-finished moles  11 - 14  of the extrusion molded part  10  have the same shape and are oriented so that they face in a common direction vertically: each of sliding surfaces  5  of the lips  3  is oriented upward, which is slidably in contact with a glass when mounted on a vehicle. The four semi-finished moles  11 - 14  are connected to a drawing element  19  with connecting elements  15 - 18 , respectively. Each of the connecting portions between the semi-finished moles  11 - 14  and the connecting elements  15 - 18  is located so that it may not interfere with the decorative surface  4  (see FIG. 1). Therefore, the surface  4  can be kept free of damage, even if the separating surfaces between the semi-finished moles  11 - 14  and the connecting elements  15 - 18  become rough or irregular at the separation.  
         [0038]    It is preferred that the thickness of the connecting elements  15 - 18  be set in the range of no less than 0.5 mm to no more than 10 mm. If it is less than 0.5 mm, it is probable that the connecting element  15 - 18  will break. On the other hand, if it exceeds 10 mm, the big force is required for cutting off the connecting elements  15 - 18 .  
         [0039]    The drawing element  19  is approximately rectangle, from the upper surface of which the first and fourth connecting elements  15  and  18  extend to be connected to the ends of the cores of the first and fourth semi-finished moles  11  and  14 , respectively. On the other hand, the second and third connecting elements  16  and  17  extend diagonally downward from the lower corners of the drawing element  19  and are connected to the ends of the cores of the second and third semi-finished moles  12  and  13 . The semi-finished moles  11 - 14  are oriented around the drawing element  19  so that the envelope falls in a circle shown with the dotted line in FIG. 2. If the four connecting elements are aligned in a line, it will require increasing of the inner diameter and the effective diameter of an extruder, which necessitates an extruder with a bigger mouthpiece. The above mentioned positioning of a near circle is preferable in order to obviate the need for such a big extruder.  
         [0040]    When the plural semi-finished moles are manufactured in parallel, the existing mouthpiece which has been employed conventionally will still be competent without modification, since the near circular positioning of the semi-finished moles  11 - 14  doesn&#39;t necessitate a big mouthpiece. Also the semi-finished moles  11 - 14  are subjected to the uniform extrusion pressure by positioning them in a near circle. Thus the shape of the manufactured mole can be stabilized.  
         [0041]    The process of manufacturing the moles shown in FIG. 1 from the extrusion molded part shown in FIG. 2 will be described referring to FIG. 3. As shown in FIG. 3, at an extrusion step S 1  the extrusion molded part  10  is extrusion molded by an extruder  20 . A core material B of PP, a lip material L and a decorative material D of TPO are supplied to the extruder  20 . The extruder  20  molds the extrusion molded part  10  with these materials by the extrusion molding.  
         [0042]    The extrusion molded part  10  molded at the extrusion step S 1  is carried to a cooling step S 2 . At the cooling step S 2 , the extrusion molded part  10  is cooled down to an appropriate temperature passing through a water tank  21 .  
         [0043]    The extrusion molded part  10  cooled down at the cooling step S 2  is carried to a separation step S 3 . At the separation step S 3 , a separation unit  22  is provided, which is for separating the semi-finished moles  11 - 14  from the drawing element  19 . The separation unit  22  comprises the physical cutting means such as a cutter or the melt cutting means such as a heat coil. The four semi-finished moles  11 - 14  are cut off from the drawing element  19  by the separation unit  22 . Subsequently, the semi-finished moles  11 - 14  are carried to a dimension measurement step S 5  and the drawing element  19  is carried to a drawing step S 4 . A drawing machine  23  for drawing the drawing element  19  is prepared at the drawing step S 4 . The drawing machine  23  has an upper conveyer  23 A and a lower conveyer  23 B, both of which interpose the drawing element  19  to draw it by the rotation of the upper and lower conveyers  23 A and  23 B.  
         [0044]    When the drawing machine  23  draws the drawing element  19 , the upper and lower surfaces of the drawing element  19  are preferably flat, since the upper and lower conveyers  23 A and  23 B interpose the drawing element  19  pressing it vertically. Only by separating the semi-finished moles  11 - 14  from the connecting elements  15 - 18 , the connecting elements  15 - 18  remain projecting from the upper and lower surfaces of the drawing element  19 . It is thereby difficult to interpose the drawing element  19  by the upper and lower conveyers  23 A and  23 B. Therefore, at the separation step S 3 , the connecting elements  15 - 18  are separated from the drawing element  19  as well as the semi-finished moles  11 - 14  from the connecting elements  15 - 18 . The upper and lower surfaces of the drawing element  19  is rendered flat by separating the connecting elements  15 - 18 , thereby allowing the upper and lower conveyers  23 A and  23 B to interpose the drawing element  19  securely. As a result, the drawing element  19  can be drawn stably; thereby the extrusion molded part  10  as well.  
         [0045]    The drawing machine  23 , which draws the drawing element  19 , gives the continuous drawing force to the semi-finished moles  11 - 14  and the extrusion molded part  10 . The semi-finished moles  11 - 14  are not interposed by the drawing machine  23  under the pressing force, thereby free from the damage. So the drawing machine  23  can interpose the drawing element  19  with relatively large force, for it is not necessary to decrease the interposing force. Therefore, the drawing machine  23  can prevent the slip between the drawing machine  23  and the drawing element  19 .  
         [0046]    The four semi-finished moles  11 - 14  separated from the drawing element  19  at the separation step S 3  are carried to the dimension measurement step S 5 . At the dimension measurement step S 5  a dimension measurement unit  24  is prepared to measure the semi-finished moles  11 - 14  for cutting and carry them to the following cutting step S 6 . At the cutting step S 6 , a cutting machine  25  is prepared, which cuts the semi-finished moles  11 - 14  according to the dimension measured at the dimension measurement step S 5  to produce the mole  1 . The manufactured mole  1  is stored in a container  26 .  
         [0047]    By manufacturing the mole  1  with the extrusion molded part  10 , which includes the plural semi-finished moles  11 - 14 , the reduction in the productivity will be restrained even if the extrusion speed is slowed down compared with the case in which a metallic core is employed. Therefore, the products such as recycling adaptable moles can be manufactured obviating the productivity drop. The existing extruder which has been used hitherto is competent for the extruder  20 , since the large mouthpiece of an extruder is rendered unnecessary by orienting the semi-finished moles  11 - 14  in a circle envelope.  
         [0048]    The drawing operation can be performed so that the drawing machine  23  may not be in contact with the semi-finished moles  11 - 14 , since the drawing machine draws the whole extrusion molded part  10  interposing only the drawing element  19 , to which the semi-finished moles  11 - 14  are connected. Therefore the semi-finished moles  11 - 14  are free from the damage caused by the drawing machine  23  coming into contact with the semi-finished moles  11 - 14 . Each of the semi-finished moles  11 - 14  is so oriented that sliding surfaces  5  (see FIG. 1) see upward. A step to turn around the semi-finished moles  11 - 14  can thus be omitted when a treatment such as the hair planting is given to the sliding surfaces  5 .  
         [0049]    Next, another example of an extrusion molded part, to which the method for manufacturing a product of thermoplastic resin and thermoplastic elastomer according to the present invention is applied, will be described referring to FIG. 2. Each shape of the following extrusion molded parts can be molded by modifying the shape of the mouthpiece for the extruder  20 .  
         [0050]    [0050]FIG. 4 is a cross sectional view showing the extrusion molded part according to the second embodiment.  
         [0051]    As shown in FIG. 4, an extrusion molded part  30  has four semi-finished moles  31 - 34 , which have the same shape and are connected to a drawing element  39  with connecting elements  35 - 38 , respectively. Each of the semi-finished moles  31 - 34  is oriented so that the sliding surfaces  5  see upward in the extrusion molded part  30 . The drawing element  39  has the cross section of trapezoid, from the upper surface of which the connecting elements  35  and  38  extend to be connected to the upward semi-finished moles  31  and  34 . The connecting elements  36  and  37 , which extend sideward from the lower portions of the sides of the drawing element  39 , are connected to the downward semi-finished moles  32  and  33 . The mole  1  according to the second embodiment is also manufactured in accordance with the process flow shown in FIG. 3. In the extrusion molded part  30 , the semi-finished moles  31 - 34  are positioned better balanced since they are positioned as described above around the drawing element  39  of a trapezoidal cross section. Therefore, the high stability of extrusion shape by the extruder  20  can be maintained. When the drawing machine  23  interposes the drawing element  39  vertically at drawing, the connecting elements  36  and  37  will be of no interference even if they remain on the drawing element  39 , since they extend sideway from the drawing element  39 . Therefore, at the separation step S 3  the drawing machine  23  can perform the secure drawing interposing the drawing element  39  even if the separation of the downward connecting elements  36  and  37  from the drawing element  39  is omitted.  
         [0052]    [0052]FIG. 5 is a cross sectional view showing the extrusion molded part according to the third embodiment.  
         [0053]    As shown in FIG. 5, an extrusion molded part  40  has four semi-finished moles  41 - 44 , which have the same shape and are connected to a drawing element  49  with connecting elements  45 - 48 , respectively. The four semi-finished moles  41 - 44  are oriented symmetrical in both vertical and horizontal directions relative to a drawing element  49 . The semi-finished moles  41 - 44  are accordingly oriented better balanced in the extrusion molded part  40  than those in the mole extrusion molded parts  10  and  30 , which results in the better stability of molding of the extrusion molded part  40  by the extruder  20 .  
         [0054]    [0054]FIG. 6 is a cross sectional view showing the extrusion molded part according to the fourth embodiment.  
         [0055]    As shown in FIG. 6, an extrusion molded part  50  has four semi-finished moles  51 - 54 , which have the same shape and are connected to a drawing element  59  with connecting elements  55 - 58 , respectively. The four semi-finished moles  51 - 54  are oriented symmetrical in both vertical and horizontal directions relative to a drawing element  59 . The high stability of extrusion molding by the extruder  20  is also attained like the third embodiment described before.  
         [0056]    The drawing element  59  has the cross section of hexagon, the top and bottom sides of which are slightly longer than the remaining sides. The top ends of the connecting elements  55  and  58 , which connect the upward semi-finished moles  51  and  54  to the drawing element  59 , stand lower than the top surface of the drawing element  59 . On the other hand, the bottom ends of the connecting elements  56  and  57 , which connect the downward semi-finished moles  52  and  53  to the drawing element  59 , stand higher than the bottom surface of the drawing element  59 .  
         [0057]    The connecting elements  55 - 58  will not go over the top or bottom surface of the drawing element  59  even if the connecting element  55 - 58  are not separated from the drawing element  59  at the separation of the semi-finished moles  51 - 54 . The semi-finished moles  51 - 54  may thus be separated from the connecting element  55 - 58  respectively leaving the connecting element  55 - 58  on the drawing element  59  at the separation step S 3  shown in FIG. 3.  
         [0058]    At the subsequent drawing step S 4 , the drawing machine  23  adds the drawing force to the drawing element  59  interposing it vertically with the upper and lower conveyers  23 A and  23 B. When the drawing machine  23  interposes the drawing element  59  vertically, the connecting elements  55 - 58  will be of no interference, since they stand receding from the top or bottom surface of the hexagonal cross section of the drawing element  59  as shown in FIG. 6. Therefore, the extrusion molded part  50  according to the fourth embodiment can be manufactured obviating the operation, in which the connecting elements  55 - 58  are separated from the drawing element  59 .  
         [0059]    [0059]FIG. 7 is a cross sectional view showing the extrusion molded part according to the fifth embodiment.  
         [0060]    As shown in FIG. 7, an extrusion molded part  60  has four semi-finished moles  61 - 64 , which have the same shape and are connected to a drawing element  69  with connecting elements  65 - 68 , respectively. The drawing element  69  has the cross section of long sideways rectangle. The connecting elements  65 - 68  extend from the both ends of top and bottom surfaces. In the extrusion molded part  60  according to the fifth embodiment, the stability of extrusion shape by the extruder  20  can be attained, since the four semi-finished moles  61 - 64  are oriented horizontally symmetrical relative to the drawing element  69 .  
         [0061]    The drawing element  69  is designed so that its cross section has the shape of long sideways rectangle. Running the upper conveyer  23 A between the upward connecting elements  65  and  68 , and the lower conveyer  23 B between the downward connecting elements  66  and  67 , the drawing machine  23  can interpose the drawing element  69  at the drawing step S 4 , even if the connecting elements  65 - 68  are not separated from the drawing element  69 . The drawing machine  23  can thus interpose and draw the drawing element  69  securely only by separating the semi-finished moles  61 - 64  from the connecting parts  65 - 68  respectively, obviating the separation of the connecting parts  65 - 68  from the drawing element  69 .  
         [0062]    [0062]FIG. 8 is a cross sectional view showing the extrusion molded part according to the sixth embodiment.  
         [0063]    As shown in FIG. 8, an extrusion molded part  70  has three semi-finished moles  71 - 73 , which have the same shape and are connected to a drawing element  77  with connecting elements  74 - 76 , respectively. The drawing element  77  has the cross section of rectangle. The connecting elements  74  and  76  extend upward from the top surface of the drawing element  77 , and the connecting element  71  downward from the bottom surface. The sixth embodiment provides the extrusion molded part  70 , by which manufacturing of three semi-finished moles  71 - 73  in parallel can be effected.  
         [0064]    The sides of the drawing element  77  are flat and the connecting elements  74 - 76  stay out of the side regions. The operation of separating the connecting elements  74 - 76  from the drawing element  77  at the separation step S 3  can be omitted if a drawing machine which has the right and left conveyers to interpose the drawing element  77  is introduced instead of the drawing machine  23 .  
         [0065]    [0065]FIG. 9 is a cross sectional view showing the extrusion molded part according to the seventh embodiment.  
         [0066]    As shown in FIG. 9, an extrusion molded part  80  has two semi-finished moles  81  and  82 , which have the same shape and are connected to a drawing element  85  with connecting elements  83  and  84 , respectively. The drawing element  85  has the cross section of rectangle, from the top surface of which the connecting elements  83  and  84  extend upward to be connected to the semi-finished moles  81  and  82 . The seventh embodiment provides the extrusion molded part  80 , by which manufacturing of two semi-finished moles  81  and  82  in parallel can be attained.  
         [0067]    Both sides of the drawing element  85  are flat and the connecting elements  83  and  84  stay out of the side regions. The operation of separating the connecting elements  83  and  84  from the drawing element  85  at the separation step S 3  can be omitted if a drawing machine which has the right and left conveyers to interpose the drawing element  85  is introduced instead of the drawing machine  23 .  
         [0068]    [0068]FIG. 10 is a cross sectional view showing the extrusion molded part according to the eighth embodiment.  
         [0069]    As shown in FIG. 10, an extrusion molded part  90  has four semi-finished moles  91 - 94 , which have the same shape and are connected to a drawing element  99  with connecting elements  95 - 98 , respectively. The disposition of the extrusion molded part  90  is the same as that of the third embodiment shown in FIG. 5. A bridge  100  connects the upward semi-finished moles  91  and  94 , and a bridge  101  connects the downward semi-finished moles  92  and  93 . These bridges reinforce the strength of the combination of the semi-finished moles  91  and  94 , and the semi-finished moles  92  and  93 , respectively.  
         [0070]    In the preparation of drawing the semi-finished moles  91 - 94  by the drawing machine  23 , the bridges  100  and  101  are separated from the semi-finished moles  91 - 94  at the separation step S 3 . Subsequently the connecting elements  95 - 98  are separated from the drawing element  99 , and the semi-finished moles  91 - 94  are cut out from the connecting elements  95 - 98 , respectively. This will complete the separation at the separation step S 3 .  
         [0071]    A connecting element with reduced portions can also be employed instead of the uniform connecting element in the embodiments described above. FIG. 11A is an enlarged view showing the connecting element shown in FIG. 2 and FIG. 11B is an enlarged view showing the connecting element with reduced portions.  
         [0072]    As shown in FIG. 11B, a connecting element  16 ′ with reduced portions has a main portion  16 A with reduced portions  16 B and  16 C at both ends. Providing the reduced portions, the stiffness of the whole extrusion molded part can be attained and the force required for the separation can be reduced as well.  
         [0073]    In the case of the uniform connecting elements  16  and  17  shown in FIG. 11A, the thickness of no less than 0.5 mm to no more than 10 mm is appropriate as described before. On the other hand, when the reduced portions  16 B,  16 C,  17 B and  17 C are provided as shown in FIG. 11B, their thickness of no less than 0.5 mm to no more than 10 mm will be desirable.  
         [0074]    It goes without saying that the connecting element according to other embodiments can also have reduced portions.  
         [0075]    It will now be appreciated from the foregoing description that the present invention is not limited to the particularly illustrated embodiment discussed above and may be carried out in various modified forms. In the embodiments described above, the descriptions have been made typically for the mole as a product, though the method can be applied to other products such as seals. In the above-mentioned embodiments, a connecting element is prepared for each semi-finished mole, which is for connecting a drawing element and a semi-finished mole. Two connecting elements or more can be provided for a semi-finished mole. The mole according to the embodiments described above is a product of both thermoplastic resin and thermoplastic elastomer. The present invention can also be applied to other products such as a product of thermoplastic resin only or a product of thermoplastic elastomer only.