Abstract:
A mold that: makes it possible to manufacture a molded foam body wherein a reinforcing member extends to a portion of an outer face of the molded body main body that corresponds to a parting line in the inner face of the cavity of the mold; and prevents molding problems stemming from the reinforcing member getting into the aforementioned parting line. Also: a method for manufacturing a molded foam body using the aforementioned mold; and a molded foam body manufactured thereby. A recessed step portion ( 6 ) that faces the cavity ( 4 ) of the aforementioned mold ( 1 ) is provided in the mating face ( 3   a ) of at least one part ( 3 ) of said mold ( 1 ), at at least a portion of the parting line (P) (formed in the inner face of the cavity ( 4 )) adjacent to which the reinforcing member ( 22 ) is disposed. Said recessed step portion ( 6 ) is designed such that if the reinforcing member ( 22 ) gets in between the mating faces ( 2   a,    3   a ) at the parting line (P) when the mold is fastened, said reinforcing member ( 22 ) can escape into the recessed step portion ( 6 ).

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a mold for manufacturing a molded foam body in which a reinforcement member is disposed across at least a portion of an outer face of a molded body main body formed from a foamable synthetic resin, and the reinforcement member is integrated with the molded body main body, and relates in particular to a mold in which the molded body main body is molded, and the reinforcement member and the molded body main body are integrated together by foaming the foamable synthetic resin raw material inside a cavity, in a state in which the reinforcement member is disposed across an inner face of the cavity. The present invention also relates to a manufacturing method for a molded foam body using the mold, and a molded foam body manufactured by the manufacturing method. 
       BACKGROUND ART 
       [0002]    Seats, such as vehicle seats or household sofas, are configured using a seat pad formed from a foamable synthetic resin, such as a flexible polyurethane foam or a semi-rigid polyurethane foam. 
         [0003]    A reinforcement member is sometimes provided to an outer face of the seat pad in order to reinforce the seat pad (Patent Document 1).  FIG. 10  is a cross-section view illustrating a conventional example of a seat pad with a reinforcement member, and  FIG. 11  is a cross-section view illustrating a conventional example of a mold for manufacturing the seat pad with a reinforcement member. Note that  FIGS. 10 ,  11  illustrate substantially the same content as FIGS. 1, 2 of Patent Document 1. 
         [0004]    A seat pad  120  as illustrated in  FIG. 10  includes a seat pad main body  121  comprising a foamable synthetic resin such as a polyurethane foam, and a reinforcement member  122  disposed across an opposite side face to a seating face of the seat pad main body  121  (hereafter referred to as the back face), and integrated with the seat pad main body  121 . The reinforcement member  122  comprises a non-woven fabric or the like. 
         [0005]    A mold  101  as illustrated in  FIG. 11  includes an upper mold  102  and a lower mold  103 . The upper mold  102  and the lower mold  103  meet at respective peripheral edge portions. The symbol P in  FIG. 11  indicates a parting line formed by joining together the respective mating faces of the peripheral edge portions of the upper mold  102  and the lower mold  103 . The seat pad  120  (the seat pad main body  121 ) is molded with the seating face in a downward facing state inside a cavity  104  that is surrounded by the upper mold  102  and the lower mold  103 . Namely, the back face of the seat pad  120  is molded by the cavity inner face of the upper mold  102 , and the seating face and side peripheral faces of the seat pad  120  are molded by the cavity inner face of the lower mold  103 . 
         [0006]    When foam molding the seat pad  120 , the reinforcement member  122  is disposed across the cavity inner face of the upper mold  102 , and the reinforcement member  122  is fixed to the upper mold  102  by a fixing (omitted from the drawings) such as a pin or a magnet. Next, foamable synthetic resin raw material is supplied into the lower mold  103 , the mold is closed, and the raw material is foamed. The seat pad main body  121  is molded, and the seat pad main body  121  and the reinforcement member  122  are integrated together, by foamed synthetic resin formed by foaming raw material filling the inside of the cavity  104 . The seat pad  120 , with the reinforcement member  122  integrally provided to the back face, is obtained by opening and removing from the mold, after the foamed synthetic resin has cured. 
       BACKGROUND ART 
       [0007]    Patent Document 1: Japanese Patent Application Laid-Open (JP-A) No. 2010-29276 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0008]    It is desirable that the reinforcement member  122  is disposed up to a terminal end of the outer peripheral side of the back face of the seat pad main body  121 , in order to evenly and sufficiently reinforce the seat pad  120  up to the terminal end side of the seating face thereof, and to make the outer edge portion of the reinforcement member  122  less liable to come away from the seat pad main body  121  due to deflection of the seat pad  120  when sat on, or the like. 
         [0009]    However, the parting line P is present on the inner face of the cavity  104  of the mold  101 , at a position corresponding to the terminal end of the outer peripheral side of the seat pad main body  121  back face. As a result, in cases in which the reinforcement member  122  is disposed up to the terminal end of the outer peripheral side of the seat pad main body  121  back face, a high level of attachment precision is required when attaching the reinforcement member  122  to the cavity inner face of the upper mold  102 , making manufacturing operations of the seat pad  120  burdensome. Namely, in such cases, the outer peripheral edge of the reinforcement member  122  needs to be aligned with the parting line P when attaching the reinforcement member  122  to the cavity inner face of the upper mold  102 . Suppose the attachment position of the reinforcement member  122  is misaligned, then there is a possibility of the reinforcement member  122  becoming trapped between the mating faces of the upper mold  102  and the lower mold  103  during mold fastening. In such cases, sealing at the parting line P after mold fastening becomes insufficient, with a possibility of molding defects occurring. 
         [0010]    As a result, as illustrated in  FIGS. 10 ,  11 , the reinforcement member  122  is conventionally designed to be somewhat smaller than the back face of the seat pad main body  121 , and the reinforcement member  122  is disposed such that the outer peripheral edge of the reinforcement member  122  is somewhat distanced from the parting line P toward the center side of the cavity inner face when attaching the reinforcement member  122  to the cavity inner face of the upper mold  102 . The required attachment precision when attaching the reinforcement member  122  to the cavity inner face of the upper mold  102  is accordingly reduced, enabling the manufacturing operation of the seat pad  120  to be made relatively simple, and also enabling relatively simple prevention of the reinforcement member  122  becoming trapped between the respective mating faces of the upper mold  102  and the lower mold  103  during mold fastening. However, it is not possible to dispose the reinforcement member  122  up to the terminal end of the outer peripheral side of the seat pad main body  121  back face using this method. 
         [0011]    Note that there is also a possibility of molding defects caused by the reinforcement member  122  becoming trapped in the parting line P occurring in cases in which the reinforcement member  122  is disposed so as to straddle positions corresponding to the parting line P on the outer face of the seat pad main body  121 . 
         [0012]    An object of the present invention is to provide a mold that enables manufacture of a molded foam body in which a reinforcement member is disposed up to a position on an outer face of a molded body main body corresponding to a parting line of a cavity inner face of the mold, and that enables prevention of molding defects caused by the reinforcement member becoming trapped in the parting line. A further object of the invention is to provide a manufacturing method of a molded foam body using the mold, and a molded foam body manufactured by the manufacturing method. 
       Solution to Problem 
       [0013]    A mold of a first aspect is a mold for manufacturing a molded foam body including a molded body main body comprising a foamable synthetic resin, and a reinforcement member disposed across at least a portion of an outer face of the molded body main body and integrated with the molded body main body, wherein: the mold includes at least two molding molds, a cavity surrounded by the molding molds is formed by fastening the molding molds together, and a parting line is formed by joining mating faces of each of the molding molds together at an inner face of the cavity; when manufacturing the molded foam body, the reinforcement member is configured to be disposed across a cavity inner face of at least one of the molding molds prior to fastening the mold, and due to such placement, to be disposed so as to be adjacent to at least a portion of the parting line inside the cavity, the mold is then fastened, and the foamable synthetic resin raw material is foamed inside the cavity; a recessed step portion facing inside the cavity is provided at the mating face of at least one of the molding molds, at at least the portion of the parting line that is disposed adjacent to the reinforcement member; and the recessed step portion is configured such that the reinforcement member is able to escape inside the recessed step portion in a case in which the reinforcement member enters between the mating faces of the parting line during mold fastening. 
         [0014]    A mold of a second aspect is the first aspect, wherein a width of the recessed step portion in an extension direction of the mating face, and in a direction towards and away from the cavity, is from 1 mm to 10 mm. 
         [0015]    A mold of a third aspect is the first or second aspect, wherein: the reinforcement member comprises a non-woven fabric with a basis weight of from 0.05 kg/m 2  to 0.2 kg/m 2 ; and a depth of the recessed step portion from the mating face is from 0.2 mm to 3 mm. 
         [0016]    A mold of a fourth aspect is any one of the first to the third aspect, wherein a seal member is provided more to an opposite side from the cavity side than the recessed step portion in order to seal between the mating faces. 
         [0017]    A manufacturing method of a fifth aspect is a manufacturing method for manufacturing a molded foam body including a molded body main body formed from a foamable synthetic resin, and a reinforcement member disposed across at least a portion of an outer face of the molded body main body and integrated with the molded body main body, using the mold of any one of the first to the fourth aspect, the manufacturing method including: a reinforcement member placement process, in which the reinforcement member is disposed across the cavity inner face of at least one of the molding molds prior to fastening the mold, and when this placement is performed, disposing the reinforcement member so as to be adjacent to at least a portion of the parting line inside the cavity; and a foam molding process, in which the mold is fastened after the reinforcement member placement process, and the foamable synthetic resin raw material is foamed inside the cavity. 
         [0018]    A manufacturing method for a molded foam body of a sixth aspect is the fifth aspect, wherein in the reinforcement member placement process, the reinforcement member is disposed such that an outer peripheral edge of the reinforcement member contacts the parting line, or such that a spacing between the outer peripheral edge of the reinforcement member and the parting line is 5 mm or less. 
         [0019]    A molded foam body of a seventh aspect is a molded foam body including a molded body main body formed from a foamable synthetic resin, and a reinforcement member disposed across at least a portion of an outer face of the molded body main body and integrated with the molded body main body, wherein the molded foam body is manufactured by the manufacturing method for a molded foam body of the fifth or the sixth aspect. 
         [0020]    A molded foam body of an eighth aspect is the seventh aspect, wherein the molded foam body is a seat pad. 
       Advantageous Effects of Invention 
       [0021]    When manufacturing the molded foam body with reinforcement member using the mold of the first aspect, the reinforcement member is disposed across a cavity inner face of at least one of the molding molds prior to fastening, and the reinforcement member is disposed so as to be adjacent to at least a portion of the parting line inside the cavity when this placement is performed. The mold is then fastened, and the foamable synthetic resin raw material is foamed inside the cavity. 
         [0022]    In the mold of the present invention, the recessed step portion facing the cavity inside is provided to the mating face of at least one of the molding molds, at at least the portion of the parting line where the reinforcement member is adjacently disposed, such that, suppose the reinforcement member enters between the mating faces of the parting line during mold fastening, the reinforcement member is able to escape inside the recessed step portion. This enables molding defects of the molded body main body caused by the reinforcement member becoming trapped in the parting line to be reliably prevented. As a result, this enables manufacture of the molded foam body disposed with the reinforcement member up to a position on the molded body main body outer face corresponding to the parting line of the cavity inner face of the mold, without occurrence of molding defects of the molded body main body. 
         [0023]    In a seat pad employed as an general vehicle seat, for example, an acceptable range of an attachment margin of error of the reinforcement member is approximately 0 mm to 5 mm. In such cases, as in the second aspect, the width of the recessed step portion in the extension direction of the mating face of the molding mold, and in the direction towards and away from the cavity, is preferably from 1 mm to 10 mm. Such a configuration enables molding defects of the molded body main body caused by the reinforcement member becoming trapped in the parting line to be more reliably prevented, even when attachment error of the reinforcement member occurs within the acceptable range. 
         [0024]    The depth of the recessed step portion from the mating face of the molding mold is suitably set according to the thickness of the reinforcement member used in the molded foam body. Note that, since it is generally difficult to unambiguously derive the thickness of the reinforcement member by actual measurement when a fabric material, such as a non-woven fabric, is used as the configuration material for the reinforcement member, it is preferable to set the depth of the recessed step portion according to the basis weight of the fabric material. Specifically, as in the third aspect, for example, in cases in which the reinforcement member is configured by a non-woven fabric with a basis weight of from 0.05 kg/m 2  to 0.2 kg/m 2 , the depth of the recessed step portion is preferably from 0.2 mm to 3 mm. Such a configuration enables the reinforcement member to be sufficiently accommodated inside the recessed step portion, even when the reinforcement member enters between the mating faces of the parting line. 
         [0025]    As in the fourth aspect, the seal member is further provided more to an opposite side from the cavity side than the recessed step portion in order to seal between the mating faces of the molding molds, thus enabling the sealing abilities of the parting line to be enhanced in cases in which the reinforcement member enters between the mating faces of the parting line. 
         [0026]    The manufacturing method of a molded foam body of a fifth aspect is for manufacturing a molded foam body with reinforcement member using the mold of the present invention. As previously described, the manufacturing method of a molded foam body of the present invention accordingly enables manufacture of a molded foam body disposed with a reinforcement member up to a position on the outer face of the molded body main body corresponding to the parting line of the cavity inner face of the mold, without causing molding defects to occur on the molded body main body. 
         [0027]    In the manufacturing method a molded foam body of the present invention, as in the sixth aspect, the reinforcement member is preferably disposed such that the spacing between the outer peripheral edge of the reinforcement member and the parting line is 5 mm or less. Disposing the reinforcement member in this way enables manufacture of the molded foam body disposed with the reinforcement member substantially up to the position on the outer face of the molded body main body corresponding to the parting line of the cavity inner face of the mold, while more reliably not inducing the occurrence of molding defects on the molded body main body. 
         [0028]    In the molded foam body of the seventh aspect manufactured by the manufacturing method of a molded foam body of the present invention, occurrence of molding defects caused by the reinforcement member becoming trapped in the parting line of the molded body main body is prevented, and the reinforcement member is disposed up to the position on the outer face of the molded body main body corresponding to the parting line of the cavity inner face of the mold. 
         [0029]    As in the eighth aspect, the present invention is suitable for application to a seat pad. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0030]      FIG. 1  is a cross-section view of a mold according to a first exemplary embodiment. 
           [0031]      FIG. 2  is an expanded cross-section view of portion II in  FIG. 1 . 
           [0032]      FIG. 3  is a plan view of a lower mold of the mold in  FIG. 1 . 
           [0033]      FIG. 4   a  is a back face view and  FIG. 4   b  is a cross-section view of a seat pad as a molded foam body manufactured using the mold in  FIG. 1 . 
           [0034]      FIGS. 5   a,    5   b  are enlarged cross-section views of the same portion as in  FIG. 2  in a case in which a reinforcement member has entered a parting line of the mold in  FIG. 1 . 
           [0035]      FIG. 6   a  is a back face view and  FIG. 6   b  is a plan view of a seat pad illustrated in a second exemplary embodiment. 
           [0036]      FIGS. 7   a,    7   b  are enlarged cross-section views of the same portion as in  FIG. 2  of a mold according to a third exemplary embodiment. 
           [0037]      FIG. 8  is a plan view of a lower mold of the mold in  FIGS. 7   a,    7   b.    
           [0038]      FIG. 9  is a plan view of a lower mold illustrated in a fourth exemplary embodiment. 
           [0039]      FIG. 10  is a cross-section view of a seat pad according to a conventional example. 
           [0040]      FIG. 11  is a cross-section view of a seat pad manufacturing mold according to a conventional example. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0041]    Explanation follows regarding exemplary embodiments, with reference to the drawings. Note that, although the following exemplary embodiments illustrate examples of application of the present invention to a mold for manufacturing a seat pad, and to a manufacturing method of a seat pad using the mold, the present invention is also applicable to a mold for manufacturing a molded foam body other than a seat pad, and to a manufacturing method for a molded foam body using the mold. 
       First Exemplary Embodiment 
       [0042]      FIG. 1  is a cross-section view of a mold according to a first exemplary embodiment.  FIG. 2  is an enlarged cross-section view of section II in  FIG. 1 .  FIG. 3  is a plan view of a lower mold of the mold.  FIG. 4   a  is a back face view of a seat pad as a molded foam body manufactured using the mold, and  FIG. 4   b  is a cross-section view taken along line IVB-IVB in  FIG. 4   a.    FIG. 5   a  and  FIG. 5   b  are enlarged cross-section views of the same portion as illustrated in  FIG. 2 , in a case in which a reinforcement member has entered a parting line of the mold.  FIG. 5   a  illustrates a state before mold fastening, and  FIG. 5   b  illustrates a state after mold fastening. 
         [0043]    In the present exemplary embodiment, a mold  1  serves to manufacture a seat pad  20  configuring a vehicle seat. Note that, although in the exemplary embodiment the seat pad  20  is a cushion pad configuring a seat section of a vehicle seat, the present invention is also applicable to a back pad configuring a backrest section of a vehicle seat.  FIG. 1  illustrates a vertical cross-section along the left-right direction of the seat pad (cushion pad)  20  during use. 
         [0044]    The seat pad  20  includes a seat pad main body  21  as a molded body main body formed from a foamable synthetic resin, such as polyurethane foam, and a reinforcement member  22  that is disposed across a back face of the seat pad main body  21  (the lower face of the seat pad main body  21  during use, since the seat pad  20  is a cushion pad in the exemplary embodiment) and integrated with the seat pad main body  21 . 
         [0045]    The reinforcement member  22  is disposed up to substantially the terminal end of the outer peripheral side of the back face of the seat pad main body  21 . In the exemplary embodiment, as illustrated in  FIGS. 4   a,    4   b,  the reinforcement member  22  is configured in a shape covering substantially the entire back face of the seat pad main body  21 , and the outer peripheral edge of the reinforcement member  22  is disposed so as to be aligned with the terminal end of the outer peripheral side of the back face of the seat pad main body  21  around the entire periphery. In the exemplary embodiment, a parting line P is present on the inner face of a cavity  4  of the mold  1 , described below, at a position corresponding to the terminal end of the outer peripheral side of the back face of the seat pad main body  21 . In the exemplary embodiment, the reinforcement member  22  is formed from an air permeable material. A non-woven fabric or the like is suitably applied as the air permeable material. 
         [0046]    Note that the shape, disposition, configuration material, and the like of the reinforcement member  22  are not limited thereto. For example, the reinforcement member  22  may be configured in a shape so as to cover a portion of the back face of the seat pad main body  21 , and a portion of the outer peripheral edge of the reinforcement member  22  may be disposed so as to be aligned with an portion of the outer peripheral side terminal end of the back face of the seat pad main body  21 . The reinforcement member  22  may be disposed at a region of the outer face of the seat pad main body  21  other than the back face of the seat pad main body  21 . The reinforcement member  22  may be disposed straddled across two or more faces out of the back face, side peripheral faces, and a seating face of the seat pad main body  21 . The reinforcement member  22  may be configured of a material other than a non-woven fabric. An air permeable member may be disposed to the reinforcement member  22  at a region overlapping with exhaust holes  5  of the mold  1 , described later. 
         [0047]    In the present invention, “the reinforcement member  22  is disposed up to substantially the terminal end (=the position on the seat pad main body  21  outer face corresponding to the parting line P of the inner face of the cavity  4  of the mold  1 , described later) of the outer peripheral side of the back face of the seat pad main body  21 ” indicates that, within a pre-set acceptable range of attachment error, the outer peripheral edge of the reinforcement member  22  may be positioned further to the center side of the back face than the outer peripheral side terminal end of the back face of the seat pad main body  21 , or may protrude out from the outer peripheral side terminal end of the back face toward the sides of the seat pad main body  21 . 
         [0048]    In the exemplary embodiment, as illustrated in  FIG. 1 , the mold  1  includes an upper mold  2  and a lower mold  3 , and exhaust holes  5  for discharging gas inside the cavity  4  surrounded by the upper mold  2  and the lower mold  3 , to outside the cavity  4 . Note that the mold  1  may also include a mold core (not illustrated in the drawings). In the exemplary embodiment, the upper mold  2  and the lower mold  3  are both equivalent to the molding molds of the first aspect. The upper mold  2  and the lower mold  3  mate together at respective peripheral edge portions. The symbol P indicates the parting line formed by joining together mating faces  2   a,    3   a  ( FIGS. 2 ,  3 ,  5   a,    5   b ) of the peripheral edge portions of the upper mold  2  and the lower mold  3 . Gas inside the cavity  4  is also discharged from the parting line P during foam molding. 
         [0049]    In the exemplary embodiment, exhaust holes  5  are provided further to the center side of a cavity inner face  2   b  of the upper mold  2  than the parting line P. The exhaust holes  5  are disposed at portions of the cavity inner face  2   b  of the upper mold  2  where it is difficult to remove gas from the parting line P alone during foam molding, such as a portion at a higher position than the parting line P, or a portion where a location lower than the parting line P exists between the portion and the parting line P.  FIG. 1  illustrates two exhaust holes  5  disposed at a spacing in the seat pad left-right direction, however the quantity and placement of the exhaust holes  5  are not limited thereto. Note that the exhaust holes  5  may also be disposed to the lower mold  3 , or the like, if required. 
         [0050]    The seat pad  20  (the seat pad main body  21 ) is molded in the cavity  4  of the mold  1  with the seating face facing downward. Namely, the seating face and side peripheral faces of the seat pad  20  are molded by a cavity inner face  3   b  of the lower mold  3 , and the back face of the seat pad  20  is molded by the cavity inner face  2   b  of the upper mold  2 . The parting line P is positioned at a boundary portion of the back face and the side peripheral faces of the seat pad  20 , namely, at the outer peripheral side terminal end of the back face of the seat pad  20 . Note that placement of the parting line P is not limited thereto, and may be disposed at a position corresponding to a location other than the outer peripheral side terminal end of the back face of the seat pad main body  21 . Prior to the foam molding process of the seat pad  20 , the reinforcement member  22  is disposed across the cavity inner face  2   b  of the upper mold  2 , and the reinforcement member  22  is fixed to the upper mold  2  by a fixing (not illustrated in the drawings) such as pins or magnets. The outer peripheral edge of the reinforcement member  22  is disposed so as to be substantially aligned with the parting line P around the entire periphery when this occurs. 
         [0051]    In the present invention, “the outer peripheral edge of the reinforcement member  22  is disposed so as to be substantially aligned with the parting line P around the entire periphery” indicates that, when attaching the reinforcement member  22  to the cavity inner face  2   b  of the upper mold  2 , within the pre-set acceptable range of attachment error, the outer peripheral edge of the reinforcement member  22  may be positioned further to the center side of the cavity inner face  2   b  than a boundary portion Bd 1  between the cavity inner face  2   b  and the mating face  2   a  of the upper mold  2 , or may protrude out from the boundary portion Bd 1  to the mating face  2   a  side (or, with the mold  1  in a fastened state, the peripheral edge portion of the reinforcement member  22  may cross the parting line P and overlap with the cavity inner face  3   b  of the lower mold  3 ). 
         [0052]    In the exemplary embodiment, a recessed step portion  6  facing inside the cavity  4  is provided to the mating face  3   a  of the lower mold  3 . The recessed step portion  6  is configured such that the reinforcement member  22  can escape inside the recessed step portion  6  in cases in which the reinforcement member  22  enters the parting line P (between the respective mating faces  2   a,    3   a ). In the exemplary embodiment, the outer peripheral edge of the reinforcement member  22  is disposed so as to be adjacent to the parting line P around the entire periphery of the parting line P, and so the recessed step portion  6  is also formed around the entire periphery of the mating face  3   a,  as illustrated in  FIG. 3 . 
         [0053]    As illustrated in  FIG. 2 , when the mold  1  has been fastened, a boundary portion Bd 2  between a bottom face of the recessed step portion  6  and the cavity inner face  3   b  of the lower mold  3 , overlaps on the extension direction of the mating faces  2   a,    3   a  with the previously described boundary portion Bd 1  between the mating face  2   a  and the cavity inner face  2   b  of the upper mold  2 . Note that the respective boundary portions Bd 1 , Bd 2  may be offset in the extension direction of the mating faces  2   a,    3   a  when the mold  1  is in a fastened state. 
         [0054]    A width W 1  of the recessed step portion  6  from the boundary portion Bd 2  in the extension direction of the mating faces  2   a,    3   a  and the direction towards and away from the cavity  4  ( FIG. 2 ; hereafter simply referred to as width W 1 ) is set as appropriate corresponding to the acceptable range of attachment error of the reinforcement member  22 , pre-set for the seat pad  20  manufactured using the mold  1 . For example, in order to configure the seat pad  20  as a common, ordinary vehicle seat, the acceptable range of attachment error of the reinforcement member  22  is approximately from 0 mm to 5 mm. In such cases, the width W 1  of the recessed step portion  6  is preferably from 1 mm to 10 mm, and particularly preferably from 5 mm to 10 mm. 
         [0055]    A depth D from the mating face  3   a  to the recessed step portion  6  bottom face ( FIG. 2 ; hereafter simply referred to as depth D) is set as appropriate according to the thickness of the reinforcement member  22  used in the seat pad  20 . Note that, since it is generally difficult to unambiguously derive the thickness of the reinforcement member  22  by actual measurement when a fabric material, such as a non-woven fabric, is used as the configuration material for the reinforcement member  22 , the depth D is preferably set according to the basis weight of the fabric material. Specifically, in cases in which the reinforcement member  22  is configured by a non-woven fabric, for example, when the basis weight of the non-woven fabric is from 0.05 kg/m 2  to 0.1 kg/m 2 , the depth D is preferably from 0.2 mm to 0.5 mm and particularly preferably from 0.3 mm to 0.4 mm, and when the basis weight of the non-woven fabric is from 0.1 kg/m 2  to 0.2 kg/m 2 , the depth D is preferably from 0.3 mm to 3 mm and particularly preferably from 0.4 mm to 0.5 mm. 
         [0056]    Note that, although in the exemplary embodiment the recessed step portion  6  is provided to the mating face  3   a  of the lower mold  3 , the recessed step portion  6  may be provided to the mating face  2   a  of the upper mold  2 , or may be provided to both the mating faces  2   a,    3   a  of the upper mold  2  and the lower mold  3 , respectively. 
         [0057]    Explanation follows regarding a procedure for manufacturing the seat pad  20  using the mold  1 . 
         [0058]    First, the upper mold  2  and the lower mold  3  are opened, the reinforcement member  22  is disposed across the cavity inner face  2   b  of the upper mold  2 , and the reinforcement member  22  is fixed to the upper mold  2  by the fixing (a reinforcement placement process). In the exemplary embodiment, the reinforcement member  22  is disposed so as to cover the entire cavity inner face  2   b  of the upper mold  2 , and the outer peripheral edge of the reinforcement member  22  is aligned around the entire periphery with the parting line P (the boundary portion Bd 1  between the cavity inner face  2   b  and the mating face  2   a  of the upper mold  2 ). 
         [0059]    Next, foamable synthetic resin raw material is poured into the lower mold  3 , the lower mold  3  and the upper mold  2  are fastened, and the raw material is foamed (a foam molding process). A foamed synthetic resin formed from the foamable raw material fills inside the cavity  4 . When this placement is performed, gas inside the cavity  4  permeates through the reinforcement member  22  formed from an air permeable material, and is discharged from the cavity  4  through the exhaust holes  5 . The seat pad main body  21  is formed, and the seat pad main body  21  and the reinforcement member  22  are integrated together by the foamable synthetic resin filling inside the cavity  4 . After the foamed synthetic resin has cured, the mold is opened and removed. The seat pad  20  is then completed by surface finishing treatment of the seat pad  20 , if required. 
         [0060]    In the mold  1 , on the respective mating faces  2   a,    3   a  of the upper mold  2  and the lower mold  3 , joined together at the parting line P that is disposed adjacent to the reinforcement member  22 , the recessed step portion  6  facing the cavity  4  inside is provided at least to the mating face  3   a  of the lower mold  3 . Suppose the reinforcement member  22  enters between the mating faces  2   a,    3   a  during mold fastening, configuration is such that the reinforcement member  22  is able to escape inside the recessed step portion  6 . This enables molding defects of the seat pad main body  21  caused by the reinforcement member  22  becoming trapped in the parting line P to be reliably prevented. This accordingly enables manufacture of the seat pad  20  disposed with the reinforcement member  22  up to a position on the seat pad main body  21  outer face corresponding to the parting line P of the cavity  4  inner face of the mold  1 , without occurrence of molding defects of the seat pad main body  21 . 
         [0061]    As previously described, since the acceptable range of attachment error of the reinforcement member  22  is approximately from 0 mm to 5 mm for a seat pad  20  used in an ordinary vehicle seat, by setting the width of the recessed step portion  6  in the extension direction of the mating faces  2   a,    3   a,  and the direction towards and away from the cavity  4 , as from 1 mm to 10 mm, and preferably from 5 mm to 10 mm, as in the exemplary embodiment, molding defects of the seat pad main body  21  caused by the reinforcement member  22  becoming trapped in the parting line P can be more reliably prevented, even when there is attachment error of the reinforcement member  22  within the acceptable range. 
         [0062]    In the exemplary embodiment, the reinforcement member  22  is configured from a non-woven fabric, and the depth D of the recessed step portion  6  is suitably set according to the basis weight of the non-woven fabric. Namely, when the basis weight of the non-woven fabric is from 0.05 kg/m 2  to 0.1 kg/m 2 , the depth D is preferably from 0.2 mm to 0.5, and when the basis weight of the non-woven fabric is from 0.1 kg/m 2  to 0.2 kg/m 2 , the depth D is preferably from 0.3 mm to 3 mm. Such a configuration enables the reinforcement member  22  to be sufficiently accommodated inside the recessed step portion  6 , even when the reinforcement member  22  enters between the mating faces  2   a,    3   a.    
       Second Exemplary Embodiment 
       [0063]      FIG. 6   a  is a back face view of a seat pad manufactured using a mold according to a second exemplary embodiment, and  FIG. 6   b  is a plan view of a lower mold of the mold. 
         [0064]    In the seat pad  20  of the first exemplary embodiment described above, the reinforcement member  22  is configured so as to cover substantially the entire back face of the seat pad main body  21 , and when the reinforcement member  22  has been disposed across the cavity inner face  2   a  of the upper mold  2 , the outer peripheral edge of the reinforcement member  22  is adjacent to the parting line P of the mold  1  around the entire periphery of the parting line P. As a result, the recessed step portion  6  serving as an escape for the reinforcement member is formed around the entire periphery of the parting line P in the first exemplary embodiment. However, in the present invention, the reinforcement member  22  may be configured so as to cover only a portion of the back face of a seat pad main body  21 . In such a case, the recessed step portion  6  serving as an escape for the reinforcement member may be provided only to portions of the parting line P adjacent to the outer peripheral edge of the reinforcement member  22 . 
         [0065]    For example, in a seat pad  20 A of the second exemplary embodiment, as illustrated in  FIG. 6   a,  the shape of a reinforcement member  22  is configured so as to cover only a front-rear direction rear half side (hereafter simply referred to as the rear half side) of a back face of a seat pad main body  21  during use of the seat pad  20 A, and the reinforcement member  22  is disposed up to the outer peripheral edge of the rear half side of the back face of the seat pad main body  21 . As a result, when the reinforcement member  22  is disposed across a cavity inner face  2   a  of an upper mold  2  (omitted from  FIG. 6   b ), the outer peripheral edge of the reinforcement member  22  is only adjacent to substantially the half-peripheral portion of the parting line P corresponding to the outer peripheral edge of the back face rear half side of the seat pad main body  21 . Accordingly, in the exemplary embodiment, as illustrated in  FIG. 6   b,  it is sufficient to provide a recessed step portion  6  to the parting line P only at substantially the half-peripheral portion rear half side adjacent to the outer peripheral edge of the reinforcement member  22 . 
         [0066]    It is preferable not to provide the recessed step portion  6  to the remaining portion of the parting line P that is not adjacent to the outer peripheral edge of the reinforcement member  22 . This prevents unnecessary burring of the seat pad main body  21 , or the like, from occurring. 
         [0067]    Note that although, as illustrated in  FIG. 6   b,  the recessed step portion  6  is provided to a mating face  3   a  of a lower mold  3  in the present exemplary embodiment, the recessed step portion  6  may be provided to the mating face  2   a  of the upper mold  2 , or provided to both the mating faces  2   a,    3   a  of the upper mold  2  and the lower mold  3 , respectively. 
         [0068]    Other configuration of the second exemplary embodiment is similar to the first exemplary embodiment. 
       Third Exemplary Embodiment 
       [0069]      FIGS. 7   a,    7   b  are enlarged cross-section views of the vicinity of a parting line of a mold according to a third exemplary embodiment (a similar portion to that illustrated in  FIG. 2 ).  FIG. 7   a  illustrates a state before mold fastening, and  FIG. 7   b  illustrates a state after mold fastening. Note that  FIGS. 7   a,    7   b  illustrate a case in which a reinforcement member has entered the parting line of the mold.  FIG. 8  is a plan view of a lower mold of the mold. 
         [0070]    A mold  1 A of the present exemplary embodiment is provided with a seal member  7  more to an opposite side from a cavity  4  than a recessed step portion  6 , in order to seal between mating faces  2   a,    3   a  of an upper mold  2  and a lower mold  3 , respectively. The seal member  7  is configured from an elastic material, such as rubber. Silicon rubber, fluorine rubber, nitrile rubber, or the like, is suitably applied as the seal member  7 , but configuration is not limited thereto. 
         [0071]    In the exemplary embodiment, a seal member attachment groove  2   c  is provided to the mating face  2   a  of the upper mold  2 , and a base end side (the upper end side in  FIGS. 7   a,    7   b ) of the seal member  7  is fixed to the upper mold  2  by fitting into the seal member attachment groove  2   c.  In the exemplary embodiment, the seal member  7  is provided around the entire periphery of the mating face  2   a  of the upper mold  2 . As illustrated in  FIG. 7   a,  when the upper mold  2  and the lower mold  3  are in an opened state, a leading end side (the lower end side in  FIGS. 7   a,    7   b ) of the seal member  7  is in a state protruding from the mating face  2   a  of the upper mold  2  toward the lower mold  3  side. During mold fastening, the leading end side of the seal member  7  is pressed against the mating face  3   a  of the lower mold  3 , and elastic close contact with the seal member  7  seals between the mating face  2   a  (the inner face of the seal member attachment groove  2   c ) of the upper mold  2  and the mating face  3   a  of the lower mold  3 . 
         [0072]    As illustrated in  FIG. 7   b,  the seal member  7  is configured so as to be capable of sufficiently sealing between the mating faces  2   a,    3   a,  even suppose a reinforcement member  22  enters a parting line P during mold fastening, and the reinforcement member  22  protrudes further to the cavity  4  outside than the recessed step portion  6  (although nearer to the cavity  4  side than the seal member  7 ) and is trapped between the mating faces  2   a,    3   a.  Namely, in the exemplary embodiment, the reinforcement member  22  is permitted to be trapped between the mating faces  2   a,    3   a  during mold fastening in a region, between the mating faces  2   a,    3   a,  from the cavity  4  inner face to the seal member  7 , and sufficient sealing is possible between the mating faces  2   a,    3   a  even if the reinforcement member  22  has become trapped therein. 
         [0073]    Similarly to the width W 1  of the recessed step portion  6 , a distance W 2  ( FIG. 7   a ) in the mating face  2   a  extension direction and the direction towards and away from the cavity  4 , from a boundary portion Bd 1  between the mating face  2   a  and the cavity inner face  2   a  to the seal member  7  (namely, the width of an acceptable region for trapping the reinforcement member), is suitably set corresponding to the acceptable range of attachment error of the reinforcement member  22 , pre-set for a seat pad  20  manufactured using the mold  1 A. For example, in order to configure the seat pad  20  as a common ordinary vehicle seat, the acceptable range of attachment error of the reinforcement member  22  is approximately from 0 mm to 5 mm. In such cases, the distance W 2  from the boundary portion Bd 1  to the seal member  7  is preferably from 1 mm to 10 mm, and particularly preferably from 5 mm to 10 mm. 
         [0074]    Note that the seal member  7  may be disposed with a spacing toward the cavity  4  outside from the recessed step portion  6 , or may be disposed adjacent to the recessed step portion  6 . The spacing between the seal member  7  and the recessed step portion  6  is preferably from 0 mm to 10 mm, and particularly preferably from 3 mm to 5 mm. 
         [0075]    Similarly to the depth D of the recessed step portion  6 , a projection height T ( FIG. 7   a ) of the seal member  7  from the mating face  2   a  with the mold in an opened state is suitably set according to the thickness of the reinforcement member  22 . It is preferable to set the projection height T of the seal member  7  according to the fabric basis weight in cases in which a fabric material, such as a non-woven fabric, is used as the configuration material of the reinforcement member  22 . Specifically, in cases in which the reinforcement member  22  is configured by a non-woven fabric, for example, when the basis weight of the non-woven fabric is from 0.05 kg/m 2  to 0.1 kg/m 2 , the projection height T is preferably from 0.2 mm to 1.5 mm and particularly preferably from 0.5 mm to 0.8 mm, and when the basis weight of the non-woven fabric is from 0.1 kg/m 2  to 0.2 kg/m 2 , the projection height T is preferably from 0.5 mm to 1.5 mm and particularly preferably from 0.8 mm to 1.2 mm. 
         [0076]    Other configuration of the mold  1 A is similar to the mold  1  of the first exemplary embodiment, and in  FIGS. 7   a,    7   b,    8 , the same reference numerals as  FIGS. 1 to 5   b  indicate the same portions. Moreover, the method of manufacturing the seat pad  20  using the mold  1 A is similar to when the mold  1  is used. 
         [0077]    The mold  1 A also exhibits similar advantageous effects to the mold  1  of the first exemplary embodiment. 
         [0078]    In the mold  1 A the seal member  7  is further provided more to the opposite side from the cavity  4  than the recessed step portion  6 , in order to seal between the mating faces  2   a,    3   a  of the upper mold  2  and the lower mold  3  respectively, thus enabling the sealing abilities of the parting line P to be enhanced in cases in which the reinforcement member  22  enters between the mating faces of the parting line P during mold fastening. 
         [0079]    In the exemplary embodiment, the seal member  7  is configured so as to be capable of sufficiently sealing between the mating faces  2   a,    3   a,  even if the reinforcement member  22  that has entered the parting line P protrudes further to the cavity  4  outside than the recessed step portion  6  (although nearer to the cavity  4  side than the seal member  7 ), and is trapped between the mating faces  2   a,    3   a.  This enables molding defects of the seat pad main body  21  caused by the reinforcement member  22  becoming trapped in the parting line P to be sufficiently prevented, even when the attachment error of the reinforcement member  22  is somewhat large. 
       Fourth Exemplary Embodiment 
       [0080]      FIG. 9  is a plan view of a lower mold of a mold according to a fourth exemplary embodiment. 
         [0081]    As in the second exemplary embodiment previously described, a seal member  7  may also be provided more to the opposite side to the cavity  4  than the recessed step portion  6  in cases in which a reinforcement member  22  is only adjacent to a portion of a parting line P, and a recessed step portion  6  is only provided to the portion of the parting line P to which the reinforcement member  22  is adjacent. 
         [0082]    In such cases, as illustrated in  FIG. 9 , it is also preferable that the seal member  7  is provided around the entire periphery of the parting line P. This enables sufficient sealing between mating faces  2   a,    3   a  around the entire periphery of the parting line P, even suppose, for example, the reinforcement member  22  is only trapped in a portion of the parting line P. In such cases, the portion of the seal member  7  surrounding the recessed step portion  6  is preferably disposed such that the distance W 2  of an acceptable region for the reinforcement member to be trapped is within the suitable range described previously, and another portion of the seal member  7  (namely, the portion where the recessed step portion  6  is not present between the seal member  7  and the cavity  4  inner face) is preferably disposed at a position as near as possible to an edge portion of an inner peripheral side (the cavity  4  side) of the mating face  2   a  and/or the mating face  3   a.  This enables intrusion of the foamable synthetic resin into the parting line P at portions where the recessed step portion  6  is not provided to be prevented as far as possible, enabling occurrence of unnecessary burring of the seat pad main body  21 , or the like, to be prevented. 
         [0083]    Other configuration of the fourth exemplary embodiment is similar to that of the second and the third exemplary embodiment. 
         [0084]    Each of the exemplary embodiments described above is merely an example of the present invention, and the present invention may be configured differently to the configurations illustrated. 
         [0085]    For example, in each of the exemplary embodiments described above, an example is given of the present invention applied to a seat back pad, however the present invention is also applicable to a molded foam body other than a seat pad. 
         [0086]    The present invention is not limited to the mating faces of an upper mold and a lower mold, and may be applied to all mating locations of a mold, such as between an upper mold and a mold core, or a lower mold and a mold core. 
         [0087]    The present invention is explained in detail herein using specific embodiments, however it is obvious to a person skilled in the art than various modifications are possible without departing from the spirit and scope of the invention. 
         [0088]    Note that the present application is based on Japanese Patent Application (No. 2012-028460) filed on Feb. 13, 2012, the entirety of which is incorporated by reference herein.