JP4841299B2 - Manufacturing method of foam products - Google Patents

Description

  The present invention relates to a method for producing foamed products having partially different physical properties.

  Conventionally, some foamed products have partially different physical properties. For example, foamed products used for cushion pads for automobile seats are seated with both sides harder than the seating part (in the case of the cushion pad for the seat) and the back contact part (in the case of the cushion pad for the backrest). In order to improve the feel of the occupant as well as to improve the feel when leaning back and back.

Conventionally, as a method for producing a foamed product having partially different physical properties, there is the following method.
(1) A foam formed in advance in a predetermined shape is set in a part of a cavity of a mold, and a foaming raw material that becomes a foam having different physical properties from the foam is injected into the remaining part of the cavity to foam. To make an integral foam.
(2) A partitioning rib is erected on the bottom surface of the cavity of the molding die, the cavity is partitioned by the partitioning rib, and different foaming raw materials are injected into the partitioned portions to cause foaming. To do.
(3) A plurality of foams having a required shape are formed from foams having different physical properties, and these foams are integrated with an adhesive or the like to form an integral foam.

  However, in the manufacturing method (1), a foam having a predetermined shape to be set in the cavity has to be manufactured in advance, which causes a problem that the manufacturing operation becomes troublesome. Moreover, when the foaming material is injected after the foam is set in advance in the mold, the foam material injected later enters the foam set in the mold (impregnation), and the boundary portion becomes hard. When the foamed product to be obtained is, for example, a vehicle seat cushion, there is a possibility that a sense of incongruity may occur due to a change in the hardness of the boundary portion when a person is seated.

  Further, in the manufacturing method of (2), since the deep groove by the partition rib is formed on the surface of the foam bottom of the foam product, for example, when the foam product is a vehicle seat cushion, the deep groove is formed on the seat surface side. When the person is seated, a problem arises in strength such as the side part of the cushion falling outside. Furthermore, since the deep groove | channel by the rib for a partition is formed in the surface by the side of the cavity bottom face of a foamed product, it will receive a big restriction | limiting in the design freedom of a foamed product.

  On the other hand, in the manufacturing method (3), since a process of forming a plurality of foams in a required shape in advance and a subsequent bonding process are required, there is a problem that manufacturing work takes time and manufacturing cost increases. Furthermore, since the boundary surface of the foam is hardened by the adhesive, when the foamed product to be obtained is a vehicle seat cushion, there is a possibility that a strange feeling may occur due to a change in the hardness of the boundary portion when a person is seated.

JP 2001-38747 A JP 2002-52550 A JP 2005-87339 A

  The present invention has been made in view of the above points, and it is easy to manufacture a foam product having partially different physical properties, and it is possible to prevent a deep groove from being formed on the design side surface of the foam product, and further, due to the deep groove. An object of the present invention is to provide a method for producing a foamed product that can hardly cause a decrease in strength.

  The invention according to claim 1 is a partition member placing step in which a box-shaped partition member having an open bottom surface is placed on the bottom surface of the cavity of the molding die, and the bottom surface of the cavity is divided into an outside and an inside of the partition member. The first foaming raw material is injected into the outside of the side surface of the partition member, while the second foaming raw material is injected into the partition member into the second foaming raw material having a physical property different from that of the first foaming raw material. A raw material injection step, the first and second foam raw materials are foamed, and at that time the volume of the second foam raw material is increased to push up the upper surface of the partition member to raise the partition member, and the first foam raw material The first foam formed by foaming and the second foam formed by foaming from the second foam raw material are joined together via the lower end of the side surface of the partition member and the bottom surface of the cavity. Foaming and And the partition member increasing step, according to the manufacturing method of the foamed product, characterized in that it comprises a.

  The invention of claim 2 is the partition member removal step of removing the partition member from the foam after finishing foaming of the first and second foam raw materials by the foaming and partition member raising step in claim 1. It is characterized by performing.

  The invention of claim 3 is the invention according to claim 1 or 2, wherein the upper surface of the partition member is allowed to pass through the second foaming raw material before starting foaming and passes through the second foaming raw material having increased viscosity after starting foaming. It is characterized by comprising a difficult mesh.

  According to the present invention, the partition member ascends from the bottom surface of the cavity according to the foaming of the second foaming raw material injected into the partition member, and the gap between the lower end of the side surface of the partition member and the bottom surface of the cavity generated thereby. Since the first foam and the second foam are joined via the gap, the obtained foam product has no deep groove formed by the side surface of the partition member on the surface on the cavity bottom surface side, and the design freedom of the foam product Is expensive. In addition, since the foamed product obtained does not have a deep groove on the cavity bottom surface, for example, in the case of a vehicle seat cushion, when a person is seated on the seat surface side, the side portion of the cushion falls outside, etc. Such strength problems do not occur. In addition, according to the present invention, there is no change in hardness that occurs at the boundary of the foam in the conventional manufacturing methods (1) and (3) described in the background art, and in the case of a seat cushion for a vehicle, There is no risk of discomfort. Furthermore, according to the present invention, it is possible to eliminate the work of forming a plurality of foams having a desired shape in advance and placing them in the mold cavity, and by injecting the first foaming raw material and the second foaming raw material into the cavity at once. Since a foamed product made of one foam can be formed, the manufacturing operation can be simplified and the manufacturing cost can be reduced.

  Hereinafter, embodiments of the present invention will be described in detail. FIG. 1 is a cross-sectional view of a mold and a partition member used in the first embodiment of the present invention, FIG. 2 is a cross-sectional view showing a state where the partition member is placed on the bottom surface of the cavity in the first embodiment, and FIG. FIG. 4 is a plan view of the lower mold in a state where the partition member is placed in the first embodiment, FIG. 4 is a cross-sectional view showing an injection state of the first and second foaming raw materials in the first embodiment, and FIG. Sectional drawing which shows the foaming state of the 1st and 2nd foaming raw material in embodiment, FIG. 6 is sectional drawing of the foaming product obtained by the 1st Embodiment.

  First, a first embodiment of the present invention will be described by taking as an example the case of producing a foam product for a vehicle seat cushion used as a cushion pad on the seating side of an automobile seat. The manufacturing method of the foamed product (vehicle seat cushion in this example) in the present invention includes a partition member placing step, a foaming raw material injecting step, and a foaming and partitioning member raising step.

  In the partition member placing step, the mold 10 as shown in FIGS. 1 and 2 is used, the partition member 20 is placed at a predetermined position on the bottom surface 13 of the cavity 12, and the bottom surface 13 of the cavity 12 is placed on the partition member 20. It is divided into the outside and the inside. FIG. 3 is a plan view of the lower mold 11 in which the partition member 20 is placed on the bottom surface 13 of the cavity 12.

  The illustrated mold 10 is for foam molding of a foam product for a vehicle seat cushion used as a cushion pad on the seat side of an automobile seat, and includes a lower mold 11 and an upper mold 18. The lower mold 11 has a cavity 12 corresponding to the shape of the foamed product as a foaming material injection and foaming space. On the other hand, the upper mold 18 is used to cover the cavity 12 and is also referred to as a lid mold. Further, in the illustrated mold 10, the design surface of the foamed product is formed by the bottom surface 13 and the side surface 14 of the cavity 12 of the lower mold 11 when foaming raw material is foamed, and the back surface of the foamed product is formed by the mold surface 19 of the upper mold 18. Form.

  The partition member 20 has a box shape with an open lower surface, and includes a side surface 21 and an upper surface 23 provided on an upper portion of the side surface 21. The partition member 20 has an appropriate shape. In the illustrated example, the partition member 20 has a rectangular parallelepiped shape with an open bottom surface. In the illustrated example, the entire circumference of the side portion of the partition member 20 is composed of side surfaces 21 (side surfaces 21a and 21a positioned in the X direction and side surfaces 21b and 21b positioned in the Y direction shown in FIG. 3). However, one side surface of the partition member 20 or a pair of opposing surfaces may be opened without forming the side surface 21. For example, in the partition member 20, a pair of side surfaces 21a and 21a may be provided on both sides in the X direction in FIG. 3, and the side portions in the Y direction may be opened without providing the side surfaces 21b and 21b. A second foaming material injection hole 24 is formed in the upper surface 23. Further, the height d1 of the partition member 20 is such that the bottom surface 13 of the cavity of the lower mold 11 and the mold surface 19 of the upper mold 18 when the molding die 10 is closed, as shown in FIG. The required amount (which varies depending on the thickness of the foamed product, for example, about 20 to 40 mm) is smaller than the distance d2 between them. In addition, when the partition member 20 is placed on the bottom surface 13 of the cavity 12, at least one set of side surfaces 21 and 21 (side surfaces 21 a positioned in the X direction in the illustrated example) on the side portion of the partition member 20. 21a) is made smaller than the cavity 12 so as to be separated from the side surfaces 14 of the cavity. When the partition member 20 is finally removed from the foamed product, the partition member 20 is made of a material having no adhesiveness to the foam or a low material when the foamed product is manufactured, or before being placed on the bottom surface 13 of the cavity. A mold release agent is applied to the surface.

  In the foaming raw material injection step, as shown in FIG. 4, the first foaming raw material P1 is placed outside the partition member 20 placed on the bottom surface 13 of the cavity 12 (in the illustrated example, outside the pair of side surfaces 21a and 21a). On the other hand, a second foaming raw material P2 that is a foam having different physical properties from the first foaming raw material P1 is injected into the inside of the partition member 20 (that is, inside the side surface 21). At this time, the second foaming raw material P2 is injected into the inside of the partition member 20 through the second foaming raw material injection hole 24 on the upper surface 23. Reference numerals N1 and N2 in FIG. 4 are foaming raw material injection nozzles. The first foaming raw material P1 and the second foaming raw material P2 are preferably polyurethane foaming raw materials. Further, as the different physical properties, the density, rebound resilience, hardness, etc. of the foam are determined according to demands, but in this embodiment, the hardness is varied. The physical properties can be easily changed by a known method, usually by changing the blending of the first foaming raw material P1 and the second foaming raw material P2 or changing the injection amount. For example, when the foaming raw material is a polyurethane foaming raw material, the physical properties can be varied by changing the type and amount of polyol, foaming agent, catalyst, polyisocyanate, foam stabilizer and the like. Furthermore, about the said 1st foaming raw material P1, you may inject | pour the multiple types of thing into the outer side of the said partition member 20 by varying the injection | pouring position. For example, the first foaming raw material P1a (not shown) is injected into the outside of one side surface 21a of the partition member 20 (left side of the partition member 20 in the drawing), and the outside of the other side surface 21a (the partition member 20 in the drawing). The first foaming raw material P1b (not shown) may be injected into the right side). In the illustrated example, after the first foaming raw material P1 and the second foaming raw material P2 are injected, the upper mold 18 is put on the lower mold 11 to perform the closed mold.

  In the foaming and partitioning member raising step, the first foaming raw material P1 and the second foaming raw material P2 are foamed as shown in (5-A) to (5-C) of FIG. At that time, the first foaming raw material P1 and the second foaming raw material P2 are foamed without being mixed by the partition member 20, and become the first foam 31 on the outside of the partition member 20, while the inside of the partition member 20 is inside. Then, the second foam 32 is obtained. Further, at the time of foaming, as shown in (5-B) of FIG. 5, the surface of the second foaming raw material P2 in the partition member 20 rises due to the volume increase due to foaming, and the upper surface 23 of the partition member 20 The upper surface 23 is pushed up by contact, and the partition member 20 is raised to separate the lower end of the side surface 21 of the partition member 20 from the bottom surface 13 of the cavity. Then, through the gap between the bottom surface 13 of the cavity generated thereby and the lower end of the side surface 21 of the partition member 20, as shown in FIG. The body 32 is joined to form one foam. The partition member 20 is raised until the upper surface 23 comes into contact with the mold surface 19 of the upper mold 18.

  Thereafter, the upper mold 18 is separated from the lower mold 11 to perform mold opening, and a desired foam product is obtained by removing one of the first foam 31 and the second foam 32. . When the partition member 20 is reused, the partition member 20 is removed from the foam after the foaming of the first and second foam raw materials is finished by the foaming and partition member raising step. A member removal process is performed. In the illustrated example, the partition member 20 is extracted and removed from the foam before or after demolding after the mold opening. FIG. 6 is a sectional view of the foamed product 30 thus obtained. In the foamed product 30, a deep groove formed by the side surface 21 of the partition member 20 does not exist on the surface 30 </ b> A on the seating surface side formed by the bottom surface 13 of the cavity 12. Moreover, when the partition member 20 is left in the foamed product, it is not necessary to perform the partition member removal step.

  A second embodiment will be described. 2nd Embodiment is an example which manufactures the foamed product for vehicle seat cushions similarly to 1st Embodiment, it replaces with the said partition member 20 in the said 1st Embodiment, and the partition shown in FIGS. Similar to the first embodiment, the member 40 is used, and includes a partition member placing step, a foaming raw material injection step, a foaming and partition member raising step, and a partition member removing step performed as necessary. . 7 is a cross-sectional view of a mold and a partition member used in the second embodiment of the present invention. FIG. 8 is a cross-sectional view showing a state in which the partition member is placed on the bottom surface of the cavity in the second embodiment. 9 is a plan view of the lower mold in a state where the partition member is placed in the second embodiment, FIG. 10 is a cross-sectional view showing an injection state of the first and second foaming raw materials in the second embodiment, and FIG. Sectional drawing which shows the foaming state of the 1st and 2nd foaming raw material in 2nd Embodiment, FIG. 12 is sectional drawing of the foamed product obtained by the 2nd Embodiment.

In the second embodiment, the partition member 40 has a net shape in which the upper surface 43 allows passage of the second foaming raw material P2 before starting foaming and makes it difficult to pass the second foaming raw material P2 having increased viscosity after starting foaming. . In the second embodiment, as shown in FIG. 10, the second foaming raw material P <b> 2 is injected into the partition member 40 via the net-like upper surface 43 of the partition member 40 during the foaming raw material injection step. The net-like upper surface 43 allows passage of the second foaming raw material P2 before starting foaming (or the raw material immediately after mixing when the foaming raw material P2 is a polyurethane raw material) and increases the viscosity after starting foaming. to difficult passes through P2, the mesh size 0.25~4.0mm ^2, particularly preferably those in the range of 1.0 to 2.0 mm ^2.

  In the second embodiment, when the first foaming raw material P1 and the second foaming raw material P2 are foamed in the foaming and partitioning member raising step, as shown in (11-A) and (11-B) of FIG. The second foaming raw material P2 in the partition member 40 increases its volume while increasing its viscosity by foaming, the surface rises, and comes into contact with the upper surface 43 of the partition member 40. Since the viscosity of the second foaming raw material P2 in contact with the upper surface 43 of the partition member 40 is increased, the second foaming raw material P2 cannot pass through the mesh-shaped upper surface 43, and pushes up the upper surface 43, thereby 40 is raised, and the lower end of the side surface 41 of the partition member 40 is separated from the bottom surface 13 of the cavity. And the 1st foam 51 formed from the said 1st foaming raw material P1 and the said 2nd foaming raw material P2 through the clearance gap between the bottom face 13 of the said cavity and the lower end of the side surface 41 of the said partition member 40 which were produced by it. The second foam 52 formed from is joined to form one foam. The partition member 40 is raised until the upper surface 43 comes into contact with the mold surface 19 of the upper mold 18.

  Thereafter, the upper mold 18 is separated from the lower mold 11 and the mold is opened, and a desired foam product is obtained by removing one of the first foam 51 and the second foam 52. . In the case where the partition member 40 is reused, the partition member 40 is removed from the foam after the foaming of the first and second foam raw materials is finished by the foaming and partition member raising step. A member removal process is performed. Other configurations are the same as those in the first embodiment. FIG. 12 shows a foamed product 50 obtained by removing the partition member 40 from the foam in the second embodiment. In the foamed product 50, a deep groove formed by the side surface 41 of the partition member 40 does not exist on the seating surface side surface 50 </ b> A formed on the bottom surface 13 of the cavity 12. In addition, when the partition member 40 is left in the foamed product, it is not necessary to perform the partition member removal step. 7-11, the code | symbol 41a, 41a shows a set of side surface located in the X direction among the side surfaces 41 of the partition member 40, On the other hand, the code | symbol 41b, 41b is a set of side surface located in a Y direction. Indicates.

  Moreover, as shown in (13-A) to (13-D) of FIG. 13, partition member positioning means 51 </ b> A to 51 </ b> D may be formed on the bottom surface 13 of the cavity. The partition member positioning means 51A shown in (13-A) is composed of a low convex portion that can sandwich the lower ends of the side surfaces 21 and 41 of the partition members 20 and 40 placed on the bottom surface 13 of the cavity. is there. On the other hand, the partition member positioning means 51B shown in (13-B) is composed of low convex portions that come into contact with the outer surfaces of the side surfaces 21, 41 of the partition members 20, 40 placed on the bottom surface 13 of the cavity, Further, the partition member positioning means 51C shown in (13-C) is formed of a low convex portion that comes into contact with the inner surfaces of the side surfaces 21 and 41 of the partition members 20 and 40 placed on the bottom surface 13 of the cavity. On the other hand, the partition member positioning means 51D shown in (13-D) includes a groove in which the lower ends of the side surfaces 21 and 41 of the partition members 20 and 40 are detachably fitted.

  When the partition member positioning means 51A to 51D are provided on the bottom surface 13 of the cavity, as shown in (14-A) to (14-D) of FIG. Seat cushions 60A-60D have small shallow recesses 63A-63C or low projections 63D formed on the surface on the seat surface side, all of which are shallow or low, and a person is seated on the seat surface side. In some cases, there is no risk of strength problems such as the side part of the cushion falling to the outside, and the influence on the degree of freedom in design is small. The recessed part 63A of the foamed product 60A is formed by the positioning means 51A, the recessed part 63B of the foamed product 60B is formed by the positioning means 51B, and the recessed part 63C of the foamed product 60C is the positioning means 51C. The convex part 63D of the foamed product 60D is formed by the positioning means 51D. Reference numerals 61A to 61D denote a first foam formed from the first foam raw material, and 62A to 62D denote a second foam formed from the second foam raw material.

It is sectional drawing of the shaping | molding die and partition member which are used in 1st Embodiment of this invention. It is sectional drawing which shows the state which mounted the partition member in the bottom face of the cavity in the 1st Embodiment. It is a top view of the lower mold | type in the state which mounted the partition member in the same 1st Embodiment. It is sectional drawing which shows the injection | pouring state of the 1st and 2nd foaming raw material in the same 1st Embodiment. It is sectional drawing which shows the foaming state of the 1st and 2nd foaming raw material in the same 1st Embodiment. It is sectional drawing of the foamed product obtained by the said 1st Embodiment. It is sectional drawing of the shaping | molding die and partition member which are used in 2nd Embodiment. It is sectional drawing which shows the state which mounted the partition member in the bottom face of the cavity in the 2nd Embodiment. It is a top view of the lower mold | type in the state which mounted the partition member in the 2nd Embodiment. It is sectional drawing which shows the injection | pouring state of the 1st and 2nd foaming raw material in the 2nd Embodiment. It is sectional drawing which shows the foaming state of the 1st and 2nd foaming raw material in the 2nd Embodiment. It is sectional drawing of the foamed product obtained by the said 2nd Embodiment. It is a fragmentary sectional view of the bottom face of the cavity which provided the positioning means for partition members. It is a fragmentary sectional view of the foamed product obtained using the shaping | molding die provided with the positioning means for partition members.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Mold 11 Lower mold 12 Cavity 13 Bottom surface of cavity 14 Side surface of cavity 18 Upper mold 19 Upper mold surface 20, 40 Partition member 21, 41 Side surface of partition member 23, 43 Upper surface of partition member 30, 50 Foam product 31 , 51 First foam 32, 52 Second foam P1 First foam raw material P2 Second foam raw material

Claims (3)

A partition member placing step of placing a box-shaped partition member having an open bottom surface on the bottom surface of the cavity of the mold and partitioning the bottom surface of the cavity into an outside and an inside of the partition member;
The first foaming raw material is injected into the outside of the side surface of the partition member, while the second foaming raw material injection into the inner side of the partition member is injected with the second foaming raw material having a physical property different from that of the first foaming raw material. Process,
The first and second foam raw materials are foamed. At that time, the upper surface of the partition member is pushed up by the volume increase due to foaming of the second foam raw material to raise the partition member, and foaming is formed from the first foam raw material. Foaming and partitioning by forming a first foam and a second foam formed by foaming from the second foaming material through a lower end of a side surface of the partition member and a bottom surface of the cavity to form one foam. A member raising process;
A method for producing a foamed product, comprising:   2. The partition member removing step of removing the partition member from the foam after the foaming of the first and second foaming raw materials is finished by the foaming and partition member raising step. Of manufacturing foam products. The upper surface of the partition member has a net shape that allows the second foaming raw material before the start of foaming to pass through and makes it difficult to pass the second foaming raw material whose viscosity has increased after the start of foaming. Or the manufacturing method of the foamed product of 2.

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