JP2018187270A - Seat cushion core material for vehicle - Google Patents

Abstract

To provide a seat cushion core material for a vehicle comprising a composite molded body that is less warped even when manufactured by insert molding and can exhibit excellent dimensional accuracy. SOLUTION: A vehicle seat cushion core material 1 comprising a composite molded body of a thermoplastic resin foamed particle molded body 2 and an annular frame member 3 embedded in the peripheral edge portion of the thermoplastic resin foamed particle molded body by insert molding. The thermoplastic resin foamed particle molded body is composed of a fused body of the thermoplastic resin foamed particles 20 (21) having through holes, and the thermoplastic resin foamed particle molded body relieves uneven shrinkage due to molding shrinkage. It has a slit 4 formed to do this. [Selection] Figure 1

Description

  The present invention relates to a vehicle seat cushion core material made of a thermoplastic resin foam particle molded body in which an annular frame member is embedded as a reinforcing member by insert molding.

  In recent years, a composite molded body composed of a thermoplastic resin foam particle molded body and a reinforcing member embedded therein has been used as a vehicle seat cushion core material. As the reinforcing member, a metal annular wire frame member is usually used, and is embedded for attachment to the vehicle body or reinforcement at the time of collision.

  Such a composite molded body is manufactured, for example, by insert molding. Specifically, first, a reinforcing member is arranged at a predetermined position in the mold, and then the thermoplastic resin foam particles are filled in the mold and heated. Thus, the foamed particles are fused to each other to obtain a thermoplastic resin foamed particle molded body, and the reinforcing member is embedded and integrated in the thermoplastic resin foamed particle molded body.

  The foamed thermoplastic resin molded article undergoes shrinkage after in-mold molding, and the shape is stabilized at a dimension smaller than the mold dimension (hereinafter, this shrinkage is also referred to as molding shrinkage). Therefore, when the thermoplastic resin foam particle molded body and the reinforcing member are integrally molded by insert molding, due to the difference in shrinkage between the thermoplastic resin foam particle molded body and the reinforcing member, In some cases, the composite molded body warps. When a composite molded body having such a warp is used as a vehicle seat cushion core material, there is a possibility that the mounting accuracy to the vehicle body is deteriorated or desired performance cannot be obtained.

  As a measure to solve these problems, the composite molded body after molding is warped by forming slits recessed in the thickness direction from the upper surface or the upper and lower surfaces of the thermoplastic resin foam particle molded body. There is a method of reducing the number (see, for example, Patent Document 1).

JP2015-174340A

  According to the proposal of patent document 1, it becomes possible to reduce the curvature of the composite molded body after molding. However, for example, when the rigidity of the reinforcing member to be embedded is small, such as a thin diameter, the effect of reducing warpage of the composite molded body may be insufficient.

  The present invention has been made in view of such a background, and even when manufactured by insert molding using a reinforcing member having low rigidity, the vehicle seat is made of a composite molded body that has less warpage and can exhibit excellent dimensional accuracy. It is an object to provide a cushion core material.

The present invention provides a vehicle seat cushion core material described below.
<1> A seat cushion core material for a vehicle comprising a composite molded body of a thermoplastic resin foamed particle molded body and an annular frame member embedded by insert molding in a peripheral portion of the thermoplastic resin foamed particle molded body, The thermoplastic resin foamed particle molded body is composed of a fused body of thermoplastic resin foamed particles having through holes, and the thermoplastic resin foamed particle molded body is formed to alleviate unequal shrinkage due to molding shrinkage. A seat cushion core material for a vehicle having a slit.
<2> The vehicle seat cushion core material according to <1>, wherein the annular frame member is a metal annular wire frame member having an average diameter of 2 to 5 mm.
<3> The vehicle according to <1> or <2>, wherein the thermoplastic resin foamed particle molded body has a bulk density of 10 to 90 kg / m ³ and a porosity of 10 to 40% by volume. Seat cushion core material.
<4> Any one of <1> to <3>, wherein an average diameter of through holes of the thermoplastic resin expanded particles constituting the thermoplastic resin expanded particle molded body is 1 to 7 mm. The seat cushion core material for vehicles as described.
<5> The vehicle seat cushion core material according to any one of <1> to <4>, wherein both side ends of the slit are positioned inward of the annular frame member.
<6> The vehicle seat cushion core material has a substantially rectangular shape in a top view having a long side and a short side, and the thermoplastic resin foam particle molded body is along a short direction of the vehicle seat cushion core material. The vehicle seat cushion core material according to any one of <1> to <5>, wherein the vehicle seat cushion core material is formed of a plurality of divided foam particle molded bodies.
<7> A plurality of foamed particle molded products in which the thermoplastic resin foamed particle molded body is divided along the short direction of the core material at a position where the longitudinal direction of the vehicle seat cushion core material is substantially equally divided. The vehicle seat cushion core material according to any one of <1> to <6>, comprising a body.
<8> The vehicle seat cushion core material has a substantially rectangular shape in a top view having a long side and a short side, and the thermoplastic resin foam particle molded body leaves one or two or more connecting portions, and is used for the vehicle. The vehicle seat cushion core material according to any one of <1> to <7>, wherein the vehicle seat cushion core material is divided along a short direction of the seat cushion core material.
<9> The vehicle seat cushion core material according to <8>, wherein the connecting portion is deformable so as to allow relative movement due to molding shrinkage of the thermoplastic resin foam particle molded body.

  The vehicle seat cushion core material of the present invention comprises a composite molded body of a thermoplastic resin foam particle molded body and an annular frame member embedded by insert molding at the peripheral edge of the foamed particle molded body. Since the molded particle is a fused product of expanded particles having through-holes, the shrinkage force of the expanded molded particle after molding is small, and further, the expanded resin molded particles of the thermoplastic resin have slits. The shrinkage force of the molded body is divided. Therefore, the vehicle seat cushion core material of the present invention can be prevented from warping and excellent in dimensional accuracy.

1 is a schematic perspective view showing an embodiment of a vehicle seat cushion core material according to the present invention. FIG. 2 is a schematic plan view showing a state in which a reinforcing member is embedded in a foamed particle molded body of the vehicle seat cushion core material shown in FIG. 1. It is a schematic sectional drawing of the part along the XX line of FIG. 1 is a schematic perspective view showing a first embodiment of a dual-purpose seat core material. (A), (b) is a schematic perspective view which shows one Embodiment of the thermoplastic resin expanded particle which has a through-hole used by this invention. (A)-(d) is a schematic explanatory drawing which shows the formation state of a slit. In embodiment shown in FIG. 5, it is a schematic explanatory drawing which shows the state which formed the slit in the upper surface. In embodiment shown in FIG. 5, it is a schematic explanatory drawing which shows the state which formed the slit in the upper surface and the lower surface. (A) is a schematic plan view which shows the position of the penetration-type slit of the seat cushion core material for vehicles, (b) is a b1-b1 arrow directional cross-sectional view in (a). (A) is a schematic plan view which shows the non-penetrating-type slit position in the seat cushion core material for vehicles, (b) is a b2-b2 arrow directional cross-sectional view in (a). (A)-(e) is a schematic plan view which shows each modification of the slit position in the seat cushion core material for vehicles. BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic which shows one Embodiment of the seat cushion core material for vehicles which consists of a thermoplastic resin foam particle molded object of the separated state divided | segmented to the longitudinal direction, (a) is a top view, (b) is in (a). It is AA sectional drawing. It is explanatory drawing of the bending deformation | transformation of the joint structure part of one form in case the thickness of a thermoplastic resin expanded particle molded object and the thickness of a joint part are the same, (a) is a figure which shows the time of no load, (b) is heat The figure which shows the bending deformation of the joint structure part when the plastic resin foaming particle molded object expand | extends and the load of a shrinking direction is added, (c) is a thermoplastic resin foaming particle compact and the load of an expansion direction is added. It is a figure which shows the bending deformation of the coupling component part in the case of a failure. It is explanatory drawing of the bending deformation | transformation of the joint structure part of the other form when the thickness of a thermoplastic resin expanded particle molded object and the thickness of a joint part are the same, (a) is a figure which shows the time of no load, (b) is heat The figure which shows a bending deformation | transformation when the plastic resin foaming particle molded object expand | extends, and the load of a shrinking direction is added, (c) is a bending when the thermoplastic resin foaming particle molded object shrink | contracts and the load of an expansion direction is added. It is a figure which shows a deformation | transformation. It is explanatory drawing which shows the form which mutually connected the base-material part of a separated state in the joint structure part, (a) is the implementation which provided the joint structure part in two places of the longitudinal direction of a thermoplastic resin foamed particle molded object The figure which shows a form, (b) is a figure which shows embodiment which provided the joint structure part in two edge parts of the transversal direction of a base material. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows one Embodiment of the vehicle seat cushion core material which consists of a thermoplastic resin foam particle molded object of the separated state divided | segmented to the transversal direction, (a) is a top view, (b) is in (a). It is AA sectional drawing. It is explanatory drawing of other embodiment of the joint structure part in case the thickness of a thermoplastic resin expanded particle molded object and the thickness of a joint part are the same, (a) is a joint part, and (b) is a joint. (C) is a figure which shows the case where a joint part is X-shaped, when a part is V-shaped. It is explanatory drawing of other embodiment of the joint structure part in case the thickness of a thermoplastic resin expanded particle molded object differs from the thickness of a joint part, (a) is a top view, (b) is the figure which showed the front view. is there. It is explanatory drawing of other embodiment of the joint structure part in case the thickness of a thermoplastic resin expanded particle molded object differs from the thickness of a joint part, (a) is a top view, (b) is the figure which showed the front view. is there. It is explanatory drawing of other embodiment of the joint structure part in case the thickness of a thermoplastic resin expanded particle molded object differs from the thickness of a joint part, (a) is a top view, (b) is the figure which showed the front view. is there.

  The vehicle seat cushion core material of the present invention (hereinafter also simply referred to as a seat core material) will be described in detail below with reference to the drawings. FIG. 1 is a schematic perspective view showing one embodiment of a sheet core material according to the present invention, and FIG. 2 is a thermoplastic resin foam particle molded body (hereinafter simply referred to as a foam particle molded body) of the sheet core material shown in FIG. FIG. 3 is a schematic cross-sectional view of a portion along line XX in FIG. 2. FIG. 4 (a) is a perspective view showing an example of a thermoplastic resin foamed particle (hereinafter simply referred to as foamed particle) having a through hole used in the present invention, and FIG. 4 (b) is used in the present invention. It is a perspective view which shows the foamed particle (multilayer foamed particle) of other embodiment used.

  The sheet core material 1 of the present invention is an integrally molded product composed of a composite molded body of a foamed particle molded body 2 and an annular frame member 3 embedded in the peripheral edge portion of the foamed particle molded body 2 by insert molding. The foamed particle molded body 2 is composed of a fused body in which the foamed particles 20 (21) having the through holes 22 are fused to each other, and was formed to alleviate unequal shrinkage due to molding shrinkage of the foamed particle molded body 2. A slit 4 is provided.

  The sheet core material 1 is an integrally molded product of the expanded particle molded body 2 and the annular frame member 3 obtained by the insert molding. That is, the sheet core material 1 is so-called mold-molded by filling the mold with the foamed particles 20 in a state where the annular frame member 3 is disposed in a mold for molding the foamed-particle molded body 2 in-mold. Obtained by insert molding.

  In the present embodiment, the integrally molded product is a molded product in which both are integrated by embedding the annular frame member 3 in the foamed particle molded body 2 when the foamed particle molded body 2 is molded in the mold. means. The integral molded product is distinguished from a sheet member manufactured by attaching the annular frame member 3 to a pre-formed molded body.

  The foamed particle molded body 2 of the present embodiment is composed of foamed particles 20 having through holes 22 as shown in FIG. Examples of the thermoplastic resin constituting the expanded particles 20 include polystyrene resins, polyolefin resins such as polyethylene and polypropylene, composite resins of polystyrene resins and polyolefin resins, polybutylene succinate, polyethylene terephthalate, polylactic acid, and the like. And other thermoplastic resins such as polyester resins and polycarbonate resins. Moreover, these thermoplastic resins may be used individually by 1 type, and may be used in combination of 2 or more types.

  The polyolefin resin is preferably a polyethylene resin or a polypropylene resin, and more preferably a polypropylene resin from the viewpoint of strength and impact resistance. Examples of the polypropylene resin include a propylene homopolymer, a copolymer of propylene and another comonomer, or a mixture thereof. Examples of the copolymer of propylene and another comonomer include a propylene-ethylene copolymer, a propylene-butene copolymer, and a propylene-ethylene-butene copolymer. In such a propylene-based resin, the propylene component unit in the resin is preferably approximately 50% by mass or more, more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

  The foamed particle molded body 2 composed of the expanded particles 20 containing a crystalline resin such as a polyolefin-based resin has a larger molding shrinkage rate than when an amorphous resin is used. On the other hand, according to the sheet core material 1 constituted by the foamed particles 20 having the through holes 22, even when a crystalline resin is used, the bending and warping are satisfactorily suppressed.

  In addition, although the foamed particle 20 of embodiment shown to Fig.4 (a) is formed in the cylindrical shape which has the through-hole 22 of the cross-sectional circle shape, it is not limited to this shape, For example, a cylinder, The foamed particles may have any shape such as an elliptical column, a rectangular column, or the like, and a shape having at least a through hole 22 penetrating the column.

  The average diameter of the through-holes 22 of the foamed particles 20 constituting the foamed particle molded body is not particularly limited, but is usually preferably 1 mm or more and 7 mm or less. The average diameter of the through-holes 22 is a virtual perfect circle having the same area as each cross-sectional area measured by measuring 50 or more cross-sectional areas of the through-holes 22 of the expanded foam particles 20 observed in the cross-sectional photograph of the foamed particle molded body 2. Can be obtained by calculating the diameter of each of them, and arithmetically averaging them. If the average diameter of the through-holes 22 is within the above range, warpage generated in the sheet core material 1 due to shrinkage of the foamed particle molded body after molding can be more effectively suppressed. From this viewpoint, the average diameter of the through holes 22 is more preferably in the range of 1 mm or more and 5 mm or less.

  In addition, the expanded particles 20 are usually substantially composed of a single layer, but are not limited to this, and may have a multilayer structure as shown in FIG. 4B, for example. Moreover, the resin which comprises each layer of the multilayer expanded particle 21 may be the same kind of resin, and may be different resin. The multilayer expanded particle 21 shown in FIG. 4B shows a expanded particle having a two-layer structure.

  In the multilayer foamed particle 21 of the embodiment shown in FIG. 4B, a cylindrical thermoplastic resin foam core layer 24 having a through hole (hereinafter sometimes simply referred to as a core layer 24) and a core layer 24 are covered. It has a multilayer structure having a thermoplastic resin coating layer 25 (hereinafter sometimes simply referred to as a coating layer 25). 4B has a two-layer structure, an arbitrary intermediate layer may be further provided between the core layer 24 and the coating layer 25.

  The core layer 24 of the multilayer foamed particles 21 is a foamed layer made of a foamed resin, whereas the coating layer 25 of the multilayer foamed particles 21 may be a resin layer made of a substantially non-foamed resin. Here, “substantially non-foamed” means only those in which no bubbles exist in the coating layer 25 (including those in which bubbles formed once melted and destroyed when foamed particles are foamed). Moreover, the thing in which a very small bubble exists slightly is also included.

  As the base resin of the core layer 24 and the coating layer 25, the same resin as the foamed particles 20 shown in FIG. 4A can be used. Among them, the core layer 24 is a polyolefin resin, and the coating layer 25 is a polyolefin. Preferably, the core layer 24 is a polypropylene resin, the covering layer 25 is a polypropylene resin or a polyethylene resin, the core layer 24 is a polypropylene resin, and the covering layer 25 is a polyethylene resin. More preferably.

  In the polyethylene resin, the ethylene component unit in the resin is preferably about 50% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, and particularly preferably 90% by mass or more. As the polyethylene resin, an ethylene homopolymer or a copolymer of ethylene and an α-olefin having 3 to 6 carbon atoms is preferably used. More specifically, for example, high-density polyethylene, low-density polyethylene, linear low-density polyethylene, ultra-low-density polyethylene, and a mixed resin of two or more of these can be used.

  When both the resin constituting the core layer 24 and the resin constituting the coating layer 25 are polyolefin resins, the resin constituting the coating layer 25 of the multilayer foamed particle 21 has a melting point higher than that of the resin constituting the core layer 24. Is preferably a low resin. Furthermore, it is more preferable that the melting point Ts (° C.) of the resin constituting the coating layer 25 is 15 ° C. or lower (Tc−15 ≧ Ts) lower than the melting point Tc (° C.) of the resin constituting the core layer 24. More preferably, the melting point Ts (° C.) of the resin that constitutes the core layer 24 is lower by 30 ° C. (Tc−30 ≧ Ts) than the melting point Tc (° C.) of the resin that constitutes the core layer 24.

  In consideration of the above points, the specific melting point of the resin constituting the core layer 24 of the multilayer expanded particle 21 is preferably approximately 120 ° C. or higher and 165 ° C. or lower, more preferably 130 ° C. or higher and 165 ° C. or lower. More preferably, it is 140 ° C. or more and 165 ° C. or less, and particularly preferably 145 ° C. or more and 165 ° C. or less. The melting point of the coating layer 25 is preferably approximately 90 ° C. or higher and 130 ° C. or lower, and more preferably 95 ° C. or higher and 125 ° C. or lower.

  As the melting point of the resin, the “when melting temperature is measured after performing a certain heat treatment” described in JIS K7121 (1987) is adopted (the heating rate and the cooling rate in adjusting the state of the test piece are both 10 ° C. When the temperature is raised by a DSC apparatus at a heating rate of 10 ° C./min and a DSC curve is drawn, the value is obtained as the apex temperature of the endothermic peak accompanying the melting of the resin on the DSC curve. is there. When there are a plurality of endothermic peaks on the DSC curve, the peak of the endothermic peak having the largest endothermic peak area is defined as the melting point. As a measuring device, for example, DSCQ1000 manufactured by TA Instruments Inc. can be used.

  Further, by making the melting point of the resin constituting the coating layer 25 lower than the melting point of the resin constituting the core layer 24, the multilayer foam particles 21 can be more reliably fused at the time of molding the foam particle molded body 2 in the mold. Meanwhile, the foamed particle molded body 2 in which the voids by the through holes 22 are maintained can be molded. Therefore, it becomes easy to control the porosity of the foamed particle molded body 2 within a predetermined range, and it is possible to obtain the foamed particle molded body 2 with good fusion, and the strength and dimensional accuracy of the sheet core material 1 can be improved. Can be improved.

  In the present embodiment, the mass ratio between the core layer 24 and the coating layer 25 is not particularly limited. However, in the embodiment in which the melting point is different between the core layer 24 and the coating layer 25 as described above, 24: The mass of the coating layer 25 is preferably 99: 1 to 75:25, more preferably the mass of the core layer 24: the mass of the coating layer 25 = 98: 2 to 80:20. In addition, the said mass ratio can be calculated by calculating | requiring the mass of each layer from the product of the density of resin which comprises each layer, and the resin volume of each layer.

  In the foamed particle molded body 2 in which the foamed particles having the through holes 22 are fused to each other, the portions of the through holes 22 of the foamed particles forming the foamed particle molded body 2 are voids. Therefore, voids are uniformly formed in the foamed particle molded body 2 over the entire molded body. Thereby, the influence of the unequal shrinkage | contraction after shaping | molding can be reduced effectively, without reducing the mechanical strength of the foamed particle molded object 2 significantly.

  The expanded particles 20 having the through holes 22 can be manufactured by appropriately selecting a known manufacturing method. For example, first, after melt-kneading a thermoplastic resin with an extruder, it is extruded into a cylindrical shape through a die and cut into an appropriate length to obtain resin particles having through holes 22. Next, the resin particles containing the foaming agent are foamed. Thereby, the expanded particle 20 which has the through-hole 22 can be manufactured. Moreover, the expanded particle 20 which has the through-hole 22 can also be manufactured by the extrusion foaming method.

From the viewpoint that the sheet core material 1 has excellent strength and appropriate elasticity, the bulk density of the foamed particle molded body 2 is preferably 10 kg / m ³ or more and 90 kg / m ³ or less. In particular, when the foamed particle molded body 2 is made of a polyolefin-based resin, the bulk density is more preferably 20 kg / m ³ or more and 60 kg / m ³ or less. A plurality of foamed particle molded bodies having different bulk densities can be combined to form one foamed particle molded body 2. In this case, each bulk density of the expanded particle molded body 2 having a different bulk density may be in the above numerical range.

The bulk density can be measured as follows. At five or more locations randomly selected from the foamed particle molded body 2, a cut sample having a predetermined size is cut out, and the volume V (cm ³ ) of the cut sample is calculated, and the mass (g) of the cut sample is measured. To do. Then, M / V is calculated by dividing the cut sample mass M (g) by the cut sample volume V (cm ³ ). The value of M / V calculated for each cut sample can be arithmetically averaged to obtain the bulk density of the foamed particle molded body 2.

  The annular frame member 3 used for the sheet core material 1 of the present invention is a member that is embedded in the foamed particle molded body 2 to reinforce the foamed particle molded body 2. Examples of the material of the annular frame member 3 include metals such as iron, aluminum, and copper, and fiber reinforced resins. Metal is preferable from the viewpoint of improving the strength of the sheet core material 1. Further, the annular frame member 3 can be used by processing a long member of any shape such as a linear shape, a tubular shape, a rod shape, etc. Among these, a rod shape or a wire having an average diameter of 2 to 5 mm, preferably 3 to 5 mm. It is preferable to use an annular metal wire frame member.

The long member preferably has a tensile strength of 200 N / mm ² or more, and more preferably 250 to 1300 N / mm ² from the viewpoint of improving the strength of the sheet core 1. The yield point is preferably 400 N / mm ² or more, and more preferably 440 N / mm ² or more. The long member having the average diameter and the tensile strength in the above numerical range can be easily formed into a predetermined shape, and the moderate strength and light weight of the sheet core 1 can be maintained. In addition, the tensile strength of a long member can be measured according to the measuring method shown by JISG3532 SWM-B. Further, the annular frame member 3 can be formed in an annular shape by welding or bending the long member.

  The shape of the annular frame member 3 in the present embodiment is appropriately designed according to the sheet core material 1 to be manufactured, but usually, as shown in FIG. 1 and FIG. Other members such as the rear latching portion 3a and the front latching portion 3b can be held. The annular frame member 3 is embedded in the foamed particle molded body 2 along the outer edge in a plan view of the foamed particle molded body 2.

  Here, the annular frame member 3 is annular. An aspect in which the long member constituting the annular frame member 3 is annularly formed without a break, and the long member constituting the annular frame member 3 is another member. Any of the embodiments configured in a ring shape via the. The continuous long member includes not only one continuous long member but also a continuous body of two or more long members joined together by welding or the like at a predetermined location. Moreover, the structure which bent the long side and the short side part according to the shape of the sheet | seat core material 1 or an attachment location, provided the crank shape 3c in part, or cut out the corner part is also included.

  The sheet core 1 integrally molded using the foamed particles 20 and the annular frame member 3 described above is manufactured by, for example, the following in-mold molding method. Specifically, the annular frame member 3 is disposed at a predetermined position in the vehicle seat cushion core molding die, and the foam particles 20 are filled in the die. Thereafter, heated steam is introduced into the mold to heat the foamed particles 20 to cause secondary foaming, and the foamed particles 20 are fused to each other. Thereby, the sheet core 1 made of a composite molded body in which the annular frame member 3 is embedded in the foamed particle molded body 2 is manufactured. The sheet core material 1 manufactured in this way is an integrally molded product of the foamed particle molded body 2 and the annular frame member 3, and is excellent in the integrity of both.

The porosity of the expanded particle molded body 2 is preferably in the range of 10% by volume to 40% by volume. When the porosity is in the above range, the sheet core material is particularly excellent in mechanical strength, and warpage of the sheet core material can be more effectively suppressed. From this viewpoint, the lower limit of the porosity is preferably 12% by volume or more, more preferably 14% by volume or more, and further preferably 16% by volume or more. Further, the upper limit of the porosity is preferably 35% by volume or less, and more preferably 30% by volume or less.
In addition, as a space | gap formed in the expanded particle molded object 2, the space | gap which exists between the expanded particles which comprise the expanded particle molded object 2, and the space | gap formed as the through-hole 22 etc. in expanded particle itself are mentioned.

The method for calculating the porosity of the foamed particle molded body 2 in the present embodiment is the bulk volume H obtained from the outer dimensions of the foamed particle molded body 2 and the apparent volume I (cm) excluding the voids of the foamed particle molded body 2. ³ ) From the following (Formula 1), the volume ratio (volume%) is calculated.
Porosity (volume%) = [(HI) / H] × 100 (Formula 1)
Specifically, it can be measured as follows.

Ten or more measurement target locations are randomly selected from the foamed particle molded body 2 after the molding shrinkage is settled, and cut samples having a rectangular parallelepiped shape of 50 cm ³ or more are cut out from each measurement target location. The cut sample is cut out so as not to have a molded skin surface. For each of the cut samples, the bulk volume H (cm ³ ) is calculated from the cut sample outer dimensions, and the apparent volume I (cm ³ ) excluding the voids of the cut sample is measured. The apparent volume I can be obtained by subtracting the volume of alcohol before the cut sample is submerged in alcohol from the total volume of alcohol and cut sample when the cut sample is submerged in alcohol. At this time, as alcohol, ethanol etc. can be used, for example. And based on the value of the bulk volume H and the value of the apparent volume I, the porosity is calculated as a volume ratio by the above (Formula 1). The value of the porosity calculated for each cut sample is arithmetically averaged and used as the porosity (volume%) for foamed particle molding and the like.

  The foamed particle molded body 2 of the present embodiment is a fusion product of the foamed particles 20 having the through-holes 22 and has voids as described above. Therefore, in the subsequent step, a core material is disposed in the mold, When the urethane stock solution is injected and foamed, and the urethane foam is laminated on the sheet core material 1, the voids of the foamed particle molded body 2 having the through-holes 22 are impregnated with the urethane stock solution to cause foaming. 1 and urethane foam can be integrated.

  The sheet core 1 formed as described above is designed in various ways depending on the type and shape of the automobile to be attached. For example, in the embodiment of the sheet core material 1 shown in FIG. 1, the recess 6 is formed as a seat portion on each of the left and right sides of the upper surface of the foamed particle molded body 2. Further, the shape of the annular frame member 3 to be embedded can be set according to the shape of the edge of the sheet core material 1. For example, in the embodiment of FIGS. 1 and 2, the rear side of the annular frame member 3 is formed in the crank shape 3 c in accordance with the thinned portion 2 b on the rear side of the sheet core 1. The concave portion 6 and the cutout portion 2b can be appropriately designed according to the structure of the vehicle body to be installed.

  Further, as shown in FIGS. 1 and 3, the sheet core material 1 has a molded body shape in which the portion 2 a in contact with the occupant's thigh is thick and the recess 6 in contact with the buttocks is thin. The thicknesses of the portion 2a in contact with the thigh and the recess 6 in contact with the buttocks are appropriately set according to the design of the seat and are not particularly limited, but usually the seat core of the recess 6 in contact with the buttocks The thickness of the material 1 is preferably 0 to 100 mm, and more preferably 5 to 70 mm. The reason why the thickness is 0 mm is that a part of the holes may be provided. In addition, the difference between the thickness of the seat member of the recess 6 that contacts the buttocks and the thickness of the portion 2a that contacts the thigh is preferably 20 to 200 mm in order to prevent the occupant from slipping out when the vehicle collides. More preferably, it is -170 mm.

  When the thickness of the sheet core 1 is uneven as described above, if the annular frame member 3 is integrally formed over the four side portions of the foamed particle molded body 2, the reinforcing portion is the central portion in the thickness direction of the foamed particle molded body 2. It may be arranged at a location that is not located at a location or a location that is biased to either the top or bottom in the thickness direction.

  In such a case, in the portion where the annular frame member 3 exists, the foamed particles are restrained by the annular frame member 3 and the shrinkage amount tends to be small, whereas in the portion where the annular frame member 3 does not exist, the shrinkage amount is large. Become. For example, if the annular frame member 3 exists at a position biased to the lower surface side in the thickness direction of the foamed particle molded body 2, the amount of contraction on the upper surface side of the foamed particle molded body 2 increases.

  That is, the foamed particle molded body 2 forming the sheet core 1 starts to contract from the time when it is taken out from the mold, and warpage occurs depending on the position of the annular frame member 3 embedded in the foamed particle molded body 2. For example, when the annular frame member 3 is embedded near the lower surface of the foamed particle molded body 2, the contraction amount of the upper part 2 b of the foamed particle molded body 2, which is a thick part at the upper part of the annular frame member 3, Since the amount of contraction of the lower part 2c of the foamed particle molded body 2 which is a thin part of the lower part of the member 3 is large, the end part may warp upward after molding.

  In the sheet core material 1 of the present invention, by using the foamed particles having the above-described through holes 22 as a material, the shrinkage force of the foamed particle molded body 2 after molding can be suppressed to be small. In order to relieve unequal shrinkage at the time of molding shrinkage of the foamed particle molded body 2 due to the frame member 3 being embedded, slits are formed in the foamed particle molded body 2. The shape and formation location of the slit 4 are not limited as long as unequal shrinkage due to molding shrinkage can be alleviated, and can be formed in various forms.

  Specifically, for example, as shown in FIG. 5, at least the foamed particle molded body 2 is recessed in the thickness direction from the upper surface (seat surface side), or from the upper surface and the lower surface (surface opposite to the seat surface). One slit 4 can be formed at a location where the annular frame member 3 is embedded so as to intersect the annular frame member 3. By forming the slit 4, the force applied by unequal shrinkage is divided and relaxed through the slit 4, and the deformation amount of the foamed particle molded body 2 can be reduced. Furthermore, in order to efficiently reduce the deformation amount of the foamed particle molded body 2, the slit 4 is formed so as to intersect the annular frame member 3.

  In the sheet core 1, the annular frame member 3 is often located on the lower surface side in the thickness direction of the foamed particle molded body 2, so that the slit 4 is at least on the upper surface of the foamed particle molded body 2 on the upper surface side of the annular frame member 3. Preferably it is formed.

Further, the depth of the slit 4 formed in the foamed particle molded body 2 in the present invention is the thickness direction from the bottom of the slit 4 formed on the upper surface of the foamed particle molded body 2 to the annular frame member 3 as shown in FIG. It is preferable that the length (a) (mm) and the length (b) (mm) in the thickness direction from the lower surface to the annular frame member 3 satisfy the following formula.
| A−b | ≦ 100 mm (1)

  That is, the length (a) (mm) in the thickness direction from the bottom of the slit 4 formed on the upper surface of the foamed particle molded body 2 to the annular frame member 3 and the length in the thickness direction from the lower surface to the annular frame member 3 ( b) By reducing the difference from (mm), it is possible to reduce the difference in force applied by the shrinkage that is different between the upper surface and the lower surface of the annular frame member 3, so that the warping of the foamed particle molded body 2 is further reduced. Can be reduced.

From the above viewpoint, preferably,
| A−b | ≦ 80 mm (2)
And more preferably
| A−b | ≦ 60 mm (3)
And more preferably
| A−b | ≦ 40 mm (4)
It is.

  On the other hand, when the thickness of the sheet core 1 is thick, as shown in FIG. 7, when the slit 4 is formed from the upper surface and the lower surface of the foamed particle molded body 2 toward the annular frame member 3, the foamed particle molded body. Since it becomes easier to control the amount of shrinkage occurring in 2, it becomes easy to reduce the warpage of the foamed particle molded body 2.

In this case, the length (a) (mm) in the thickness direction from the bottom of the slit 4 formed on the upper surface of the foamed particle molded body 2 to the annular frame member 3, and the bottom of the slit 4 formed on the lower surface from the annular frame. It is preferable that the length (c) (mm) in the thickness direction up to the member 3 satisfies the following formula.
| A-c | ≦ 100 mm (5)
Preferably,
| Ac- ≦ 80 mm (6)
And more preferably
| Ac | ≦ 60 mm (7)
And more preferably
| Ac | ≦ 40 mm (8)
It is.

  In addition, when forming the slit 4 from the upper surface and the lower surface of the foamed particle molded body 2 toward the annular frame member 3, the slit 4 on the upper surface and the lower surface can be formed at a pair of opposing positions. The lower slit 4 may be formed in the middle of the two slits 4 formed on the upper surface. In such a case, it is preferable that the lengths (a) and (c) satisfy the above formula with respect to the space between the adjacent slits 4.

  The direction in which the slit 4 is formed is appropriately set according to the shape and size of the sheet core 1 to be manufactured so as to intersect with the annular frame member 3. Crossing here means a state in which the annular frame member 3 is observed crossing the slit 4 in a two-dimensional plane in which the automobile seat member is observed from above. The slit 4 is preferably formed in a direction perpendicular to the annular frame member 3 of the sheet core 1.

  The slit 4 is preferably formed at a position that equally divides the length of the sheet core 1 in the longitudinal direction, and may be formed at a position that equally divides the longitudinal direction of the sheet member into two. Further, a larger number of slits 4 may be formed, and the slits 4 may be formed at positions that are equally divided into three or at positions that are equally divided.

  As shown in FIG. 5, when the annular frame member 3 is rectangular, the slit 4 to be formed is formed in the vertical direction at least on the upper surface side of the portion where the annular frame member 3 is embedded. It is preferable. That is, as shown in FIG. 5C, the annular frame member 3 may be formed long so as to straddle two pieces, or as shown in FIG. 5A, the annular frame member 3 may be formed short so as to straddle one piece. May be. From the above viewpoint, the length of the slit 4 is preferably 50 mm or more and more preferably 100 mm or more across the annular frame member 3.

  The number of slits 4 to be formed can be appropriately set according to the shape and size of the sheet core material 1 to be manufactured. In the case of the sheet core material 1 for an automobile having a large vehicle width, FIG. Three or more can be formed as in b).

  Moreover, in the slit 4 formed in the sheet | seat core material 1 of this invention, as another embodiment, the slit 4 which can be formed in the foaming particle molded object 2 as shown in FIGS. 8-10 is illustrated, for example. Can do.

  Specifically, for example, the slit 4 can be formed in a region close to the annular frame member 3, and the slit 4 can be formed in the vicinity of the annular frame member 3 in parallel with the extending direction of the annular frame member 3. . Moreover, the slit 4 can also be formed in a direction orthogonal to the extending direction of the annular frame member 3. A slit 4 that intersects the annular frame member 3 can also be formed. Furthermore, the slit 4 extended in the width direction of a vehicle and the slit 4 extended in the front-back direction of a vehicle can be formed. It is also possible to combine a plurality of slits 4. In addition, the parallel or orthogonal here may be parallel or orthogonal as a whole in appearance, and includes those having a slight inclination from the exact parallel or orthogonal.

  The slit 4 may penetrate the thickness direction of the foamed particle molded body 2. That is, the slit 4 may penetrate from the upper surface to the lower surface of the foamed particle molded body 2 of the sheet core material 1 in the thickness direction. The slit 4 may be a bottomed groove without penetrating the foamed particle molded body 2 in the thickness direction. That is, the slit includes a through groove and a bottomed groove.

  Hereinafter, the example of the slit 4 shown in FIGS. 8 to 10 will be described in more detail. 8A, 9 </ b> A, and 10 </ b> A to 10 </ b> E, the upper part of the drawing corresponds to the rear side, and the lower part corresponds to the front side.

FIGS. 8A and 8B show an embodiment of a slit 4d extending in the front-rear direction of the sheet core 1 having a substantially rectangular shape in top view and having a long side and a short side. As shown in FIG. 8A, the slit 4 d is formed from the front to the rear of the foamed particle molded body 2, and divides the foamed particle molded body 2 along the short direction of the sheet core material 1. ing. That is, the slit 4 d is formed from the front end to the rear end of the foamed particle molded body 2. Such a slit 4d intersects a pair of sides (that is, the front frame portion 31 and the rear frame portion 32) extending in parallel with the vehicle width direction in the annular frame member 3. Moreover, as illustrated in FIG. 8B, the slit 4 can be provided so as to penetrate the foamed particle molded body 2 in the thickness direction.
In the present embodiment, one slit is provided along the short direction from the substantially longitudinal center, but a plurality of slits may be provided. In addition, when a plurality of slits are provided, a plurality of slits can be provided along the short direction at a position where the longitudinal direction of the sheet core 1 is substantially equally divided.

  FIG. 9A and FIG. 9B show an embodiment of the slit 4 e extending in the front-rear direction of the sheet core 1. The slit 4e is the same as the slit 4d described above in that it extends in the front-rear direction, but does not penetrate the foamed particle molded body 2 in the thickness direction as shown in FIG. 9B. That is, the slit 4e is a bottomed groove formed from the upper surface to a predetermined depth. As shown in FIGS. 9A and 9B, the slit 4e may be a through-groove that penetrates the foamed particle molded body 2 in the thickness direction or a non-penetrating bottomed groove. .

  According to the embodiment shown in FIGS. 8A and 9A, the slits 4d and 4e extending in the front-rear direction of the sheet core material 1 transmit the contraction force of the foamed particle molded body 2 in the width direction. Can be relaxed. Thereby, generation | occurrence | production of the curvature of the sheet core material 1 can be suppressed more. Further, according to the embodiment shown in FIG. 9B, when the slit 4 is a bottomed groove like the slit 4 e, the foamed particle molded body 2 is not divided by the slit 4. Warpage can be suppressed without losing the sense of unity.

  10 (a) to 10 (e) show further different slit embodiments. In addition, the slit 4 having the shape shown in FIGS. 10A to 10E may be a penetration type penetrating the foamed particle molded body 2 or a non-penetration type.

  FIG. 10A shows an embodiment of a slit 4f extending in the vehicle width direction. Both ends of the slit 4f in the extending direction do not reach the both ends on the side of the foamed particle molded body 2, but are formed inside the both ends. Furthermore, it is formed inside the annular frame member 3 embedded in the foamed particle molded body 2. That is, both ends of the slit 4 f in the extending direction are formed at positions on the inner side of the side frame portion 33 of the annular frame member 3. The slit 4 is formed in a region on the rear side of the foamed particle molded body 2. The slit 4 is formed along a rear side (that is, the rear frame portion 32) extending in the vehicle width direction of the annular frame member 3, and is formed in the vicinity of this side and on the inner side (front side) of this side. ing.

  FIG. 10B shows an embodiment of a plurality of slits 4g, 4h, 4i extending in the vehicle width direction. In this way, a plurality of slits 4 can be formed. The slits 4g and 4h are formed in parallel in the vehicle width direction, and both are formed inside the annular frame member 3 embedded in the foamed particle molded body 2. Further, the slits 4g and 4h are all formed in a region on the rear side of the sheet core 1. Further, a slit 4i may be formed between the two slits 4g and 4h. The slit 4i can be formed so that the center of the slit 4i is disposed between the two slits 4g and 4h. In FIG. 10B, the slit 4i is formed further inside (that is, the front side) than the slits 4g and 4h, but may be formed on the rear side.

  FIG. 10C shows an embodiment of the slit 4 j that extends in the vehicle width direction and whose both ends reach the outside of the annular frame member 3. Both ends of the slit 4j in the extending direction do not reach the both ends on the side of the foamed particle molded body 2, but are formed inside the both ends. However, compared with the slit 4 f shown in FIG. 10A, both ends of the slit 4 j are extended in the vehicle width direction and reach the outside of the annular frame member 3 embedded in the foamed particle molded body 2. The slit 4j is formed in a region on the rear side of the foamed particle molded body 2, and is formed inside the annular frame member 3 in the front-rear direction.

  When the annular frame member 3 is an annular wire frame member and the rigidity of the annular wire frame is low, the central portion of the rear frame portion 32 of the annular frame member 3 is easily pulled forward by contraction of the thick portion, and The frame member 3 is distorted, and as a result, the sheet core 1 is easily warped. In particular, if the rear frame portion 32 side of the annular frame member 3 has a crank shape as shown in FIG. 2, the rigidity of the rear frame portion 32 becomes low. In the body 2, the center part in the width direction of the rear frame part 32 is easily pulled inward. Therefore, large distortion is generated in the annular frame member 3 itself, and the warp of the sheet core material 1 tends to be larger. Therefore, as shown in FIGS. 10A to 10C, by forming slits 4 extending in the width direction in the foamed particle molded body 2, the contraction of the foamed particle molded body 2 is transmitted in the front-rear direction. Can be relaxed. Thereby, generation | occurrence | production of the curvature of the sheet core material 1 can be suppressed more. Further, although not shown, the slits 4f to 4j may be formed in a region on the front side of the foamed particle molded body 2 in the front-rear direction as long as it is inside the annular frame member 3.

  FIG. 10 (d) shows an embodiment of two slits 4 k and 4 l extending in the front-rear direction of the sheet core 1. Both ends of the slits 4k, 4l in the extending direction do not reach both ends in the front-rear direction of the foamed particle molded body 2, and are formed inside the both ends. Furthermore, it is formed inside the annular frame member 3 embedded in the foamed particle molded body 2. That is, both ends of the slits 4k and 4l in the extending direction are formed at positions inward of the front frame portion 31 and the rear frame portion 32, respectively. Inside the annular frame member 3, the slits 4k4l are formed along side sides (side frame portions 33) extending in the front-rear direction of the annular frame member 3.

  Further, the sheet core 1 is contracted by the foamed particle molded body 2 so that the center part of the side frame portion 33 is pulled inward by the foamed particle molded body 2, and the annular frame member 3 is distorted. The sheet core material 1 may be easily warped. Furthermore, as described above, if the rigidity of the annular frame member 3 on the rear frame part 32 side is low, the foamed particle molded body 2 contracts in the center part in the width direction of the rear frame part 32 due to shrinkage of the foamed particle molded body 2. It becomes easy to be pulled to the side. Therefore, since the side frame portion 33 is pulled inward and the rear frame 33 is also pulled inward, the distortion of the annular frame member 3 is further increased, so that the warp of the seat core 1 may be particularly large. . In such a case, as shown in FIG. 10D, slits 4k and 4l extending in the front-rear direction are formed on the sides to reduce the influence of the contraction force of the foamed particle molded body 2 on the side frame portion 33. it can. Thereby, generation | occurrence | production of the curvature of the sheet core material 1 can be suppressed more. Although not shown, the slits 4k and 4l may be combined with the slits 4g and 4h.

  FIG. 10 (e) shows an embodiment of two slits 4m, 4n extending in the front-rear direction and the vehicle width direction and intersecting each other. The slits 4m are formed from the front to the rear of the foamed particle molded body 2 in the same manner as the slits shown in FIGS. 9A and 9A, and divide the foamed particle molded body 2. That is, the slit 4 m is formed from the front end portion to the rear end portion of the foamed particle molded body 2. The slit 4n is formed so as to extend in the vehicle width direction of the foamed particle molded body 2. Both ends of the slit 4n reach both lateral ends of the foamed particle molded body 2 to divide the foamed particle molded body 2. The slit 4n is formed closer to the rear in the front-rear direction. The slit 4m and the slit 4n intersect each other.

  As shown in FIG. 10 (e), when two slits 4 extending in the front-rear direction and the vehicle width direction and intersecting each other are formed, the contraction force of the foamed particle molded body 2 is transmitted in the front-rear direction and the vehicle width direction. Can be relaxed. Thereby, generation | occurrence | production of the curvature of the sheet core material 1 can be suppressed more.

  In addition, in the sheet core material 1 of the present invention, in addition to the above-described embodiment, the foamed particle molded body 2 is divided along the short direction of the sheet core material 1 leaving one or more connecting portions. It can also be provided. Further, it is preferable that the connecting portion is formed so as to be variable so as to allow relative movement due to molding shrinkage of the foamed particle molded body 2.

  Specifically, the foamed particle molded body 2 is provided with one or more joint component parts that separate the foamed particle molded body 2 into the plurality of foamed particle molded bodies 2 in a direction intersecting the connecting portion. The joint part 5 is composed of one or a plurality of joint parts 5 connecting two adjacent foamed particle molded body parts 26 and 27, and each of the joint parts is adjacent when the foamed particle molded body 2 contracts or expands. It can be formed to be deformable so as to allow relative movement between the two expanded particle molded body portions 26, 27.

  As an example of the arrangement form of the single joint component 28 with respect to the foamed particle molded body 2, as shown in FIG. 11, there is one joint component 28 in the longitudinal direction L and over both ends in the short direction S. An embodiment in which the joint component 28 is formed in one position in the short direction S and over both ends in the longitudinal direction L is illustrated as shown in FIG. Moreover, as an example of the arrangement | positioning form with respect to the foaming particle molded object 2 of the some joint structure part 28, as shown to Fig.14 (a), it extends over the both ends of the transversal direction S at two places in the longitudinal direction L. As shown in FIG. 14 (b), the embodiment is formed at one location in the longitudinal direction L and at both ends in the lateral direction S, or the longitudinal direction L or the lateral direction. Examples include an embodiment in which the foamed particle molded body portions 26 and 27 that are separated in the direction S are connected by a joint type structure portion 28 having a joint portion 5 provided with a plurality of intermittently. The joint form structure portion 28 is disposed in the foamed particle molded body 2 at any position that intersects the connecting portion 23 of the annular frame member 3 so that the joint type structure section 28 can be bent and deformed. Any embodiment may be used.

  Below, the structure of the joint structure part 28 is demonstrated. As shown in FIGS. 12, 13, and 16 to 19, the joint constituent portion 28 constitutes a joint portion 5 that connects the foamed particle molded body portions 26 and 27 on both sides of the joint constituent portion 28. As shown in FIG. 12 and the like, the joint portion 5 is shifted in the longitudinal direction L, the lateral direction S, and the thickness direction T at the position of the connecting portion K with the foamed particle molded body portions 26 and 27. Or the joint portion 5 itself has a bent shape with the position of the connecting portion K facing each other in the longitudinal direction L, the lateral direction S, and the thickness direction T, as shown in FIG. Is preferred. Moreover, it is preferable that the slit 4 or the slit 4a for making the joint part 5 bendable and deformable is provided in the both sides of the joint part 5 like illustration.

  The positions of the connecting portions K between the two adjacent expanded particle molded body portions 26 and 27 are connected in a state shifted in the longitudinal direction L, the short direction S or the thickness direction T, or the position of the connecting portion K is changed. When facing in the longitudinal direction L, the lateral direction S, and the thickness direction T, the joint portion 5 can be bent and deformed by making the joint portion 5 itself a bent shape. When the foamed particle molded body 2 expands and contracts due to unequal contraction or the like, the joint portion 5 flexibly bends and deforms to absorb the expansion and contraction. This can prevent the foamed particle molded body 2 from being deformed such as warping due to expansion and contraction.

  Moreover, as a preferable aspect, the connection site | part K of the both sides of the joint part 5 of the joint structure part 28 is connected with the foamed particle molded body parts 26 and 27 only by the joint part 5, and the foamed particle molded body parts 26 and 27 of both sides are connected. 14 (b), for example, in the range of the joint component 28 with respect to the longitudinal direction L and in the range where the joint portion 5 does not exist in the short direction S. A slit 4 is provided for separating the foamed particle molded body portions 26, 27 on both sides.

  The example of embodiment of the joint part 5 is demonstrated according to embodiment of the connection part K of the joint part 5 and the foaming particle molded object parts 26 and 27 of both sides. The embodiment of the joint portion 5 differs depending on the thickness relationship between the joint portion 5 and the foamed particle molded body members 26, 27 and the positional relationship in the longitudinal direction L, the short direction S, or the thickness direction T of the connecting portion K.

  First, as shown in FIGS. 12, 13, and 16, when the thickness of the joint portion 5 is the same as the thickness of the foamed particle molded body portions 26 and 27, and as shown in FIGS. The thickness may be different from that of the foamed particle molded body portions 26 and 27.

  An embodiment of the joint portion 5 in which the thickness of the joint portion 5 is the same as the thickness of the foamed particle molded body portions 26 and 27 and the connecting portion K is shifted in the longitudinal direction L or the short direction S is shown in FIG. In this embodiment, the connecting portion K is shifted in the short direction S and the slits 4a are arranged on both sides, as shown in FIG. 16A, the joint portion 5 shown in FIG. An embodiment in which the slits 4a are arranged on both sides by shifting in the direction S, and the joint portion 5 in which the connecting portion K is shifted in the short direction S as shown in FIG. There is an embodiment in which the slits 4 are arranged on both sides. These embodiments are examples, and the embodiment of the joint portion 5 may be any embodiment that can be bent and deformed in the longitudinal direction and / or the lateral direction.

  Next, in the case where the thickness of the joint portion 5 is the same as the thickness of the foamed particle molded body portions 26 and 27, the joint portion 5 is made to face the connecting portion K in the longitudinal direction L, the short side direction S, and the thickness direction T. In the embodiment, for example, as shown in FIG. 13, the position of the connecting portion K is matched in the longitudinal direction L, the short side direction S, and the thickness direction T, and a bent portion is provided in a plan view to form a substantially U shape. Embodiment arranged on both sides, as shown in FIG. 16 (b), the position of the connecting portion K is made to coincide in the longitudinal direction L, the transverse direction S, and the thickness direction T, and a bent portion is provided in a plan view so as to be substantially V-shaped. There is an embodiment in which a slit is provided on both sides as a mold. These embodiments are examples, and the embodiment of the joint portion 5 may be any embodiment that can be bent and deformed in the longitudinal direction and / or the lateral direction.

  Next, in the case where the thickness of the joint portion 5 is different from the thickness of the foamed particle molded body portions 26 and 27, the embodiment of the joint portion 5 in which the connecting portion K is shifted in the longitudinal direction L, the lateral direction S, or the thickness direction T is For example, as shown in FIG. 18, the thickness of the joint portion 5 is made thinner than the thickness of the foamed particle molded body portions 26 and 27, and the connecting portion K is shifted in the short direction S and the thickness direction T so that the slits 4a are arranged on both sides. As shown in FIG. 19, the joint portion 5 is made thinner than the foamed particle molded body portions 26 and 27, and the foamed particle molded body member 26 has two connecting portions K for the foamed particle molded body member 26. An embodiment in which the body member 27 is formed in a substantially V shape in plan view with one place, the connecting portion K is shifted in the short direction S and the thickness direction T, and the slit 4a and the slit 4 are respectively disposed on both sides. There is. These embodiments are examples, and the embodiment of the joint portion 5 may be any embodiment that can be bent and deformed in the longitudinal direction and / or the lateral direction.

  Next, in the case where the thickness of the joint portion 5 is different from the thickness of the foamed particle molded body portions 26 and 27, the joint portion 5 is made to face the connecting portion K in the longitudinal direction L, the short side direction S, and the thickness direction T. In the embodiment, for example, as shown in FIG. 17, the thickness of the joint portion 5 is made thinner than the thickness of the foamed particle molded body portions 26, 27, and the connecting portion K is positive in the longitudinal direction L, the short direction S, and the thickness direction T. On the other hand, there is an embodiment in which a bent portion is provided in a plan view so as to be substantially V-shaped and the slits 4a are disposed on both sides. These embodiments are examples, and the embodiment of the joint portion 5 may be any embodiment that can be bent and deformed in the longitudinal direction and / or the lateral direction.

  Next, bending deformation of the joint part 5 of the joint type structure part 28 will be described with reference to FIG. 12 (a) and 13 (a) show embodiments at the time of designing the foamed particle molded body portions 26 and 27 made of the foamed particle molded body 2, and FIGS. 12 (b) and 13 (b) show the expanded particles. FIG. 12 (c) and FIG. 13 (c) show the bending deformation state of the joint portion 5 when the expanded particle molded body portions 26 and 27 made of the molded body 2 are dimensionally expanded. The bending deformation state of the joint part 5 when the expanded particle molded body portions 26 and 27 are reduced in size is shown. In this way, the expansion or contraction of the foamed particle molded body portions 26 and 27 made of the foamed particle molded body 2 can be dimensionally absorbed by the bending deformation of the joint portion 5. Thereby, deformation | transformation of the expanded particle molded object parts 26 and 27 can be prevented, and the dimensional accuracy of the elongate foaming component 1 which consists of the expanded particle molded object 2 can be stabilized.

  In addition, it is necessary to form the slit 4 formed in the sheet core material 1 of the present embodiment as quickly as possible from the time when the sheet core material 1 molded by the molding apparatus is taken out of the molding die until warpage occurs. Therefore, after taking out from a shaping | molding die, it can cut with a cutter, a heat ray, etc. in the preset place and depth. In addition, the slit 4 may be formed in advance by forming a ridge for forming the slit 4 in the mold in addition to the cutting by the cutter or the like. Moreover, it is preferable that it is 0.1-20 mm, and, as for the width | variety of the slit 4 formed, it is more preferable that it is 0.2-10 mm.

  While the present invention has been described based on the embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. For example, the formation pattern of the slit 4 is not limited to one type, and can be formed by combining two types of slit formation patterns. Moreover, it can also form so that it may become asymmetrical back and forth, and right and left according to the design of the sheet core material 1.

  The shape and dimensions of the seat core 1 can be appropriately modified according to the vehicle to be mounted. However, when the seat core 1 is a seat core for a rear seat of the vehicle, the shape of the seat core is as viewed from above. The length in the longitudinal direction is adjusted to 1000 to 1500 mm, and the length in the short direction is adjusted to about 400 to 700 mm. The thickness of the sheet core 1 can be about 5 to 300 mm, and does not necessarily have a uniform thickness. In addition, thickness means the length of the up-down direction in the state which attached the sheet | seat core material 1 to the vehicle body.

  According to the sheet core material 1 of the present invention, the foamed particle molded body 2 is a fused body of the foamed particles 20 (21) having the through holes 22, so that the shrinkage force of the foamed particle molded body 2 after molding is reduced. Further, by forming the slits 4 in the foamed particle molded body 2, the contraction force of the foamed particle molded body 2 is divided, warpage is further suppressed, and the sheet core material 1 having an excellent dimensional system can be obtained. .

  In addition, since the foamed particle molded body 2 is a fusion product of the foamed particles 20 (22) having the through holes 22, a core material is disposed in the molding die and a urethane stock solution is injected into the die in a subsequent process. When foaming and laminating urethane foam on the sheet core 1, the voids of the foamed particle molded body 2 are impregnated with a urethane stock solution and foamed to strengthen the urethane foam having poor adhesion to the sheet core 1. Can be integrated.

  Hereinafter, the sheet core material of the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

(Example 1)
Using the molding apparatus, the sheet core material of Example 1 was manufactured by integrating the foamed particle molded body and the annular frame member.
As the raw material foam particles, multi-layer foam particles having a sheath core structure composed of a cylindrical core layer having foamed through-holes and a non-foamed cover layer covering the peripheral side surface of the core layer were used. The core layer was formed from a polypropylene resin having a melting point of 142 ° C., and the coating layer was formed from a polypropylene resin having a melting point of 127 ° C. The mass ratio of the core layer to the coating layer was 95: 5. The bulk density of the expanded particles was 25 kg / m ³ , the average particle mass was 1.5 mg, the average diameter of the through holes was 1.9 mm, and the average L / D was 0.8.

  The annular frame member is a metal annular wire frame member having a thickness of 4.5 mm, and has a substantially rectangular outer shape when viewed from the top as shown in FIGS. 2 and 3, with a maximum longitudinal dimension of 1040 mm and a maximum lateral dimension of 430 mm. In addition, it was bent in the vicinity of the central portion in the front-rear direction in a side view, the step between the front portion and the rear portion was 30 mm, and had two bent portions in the rear portion.

  Then, the above-mentioned foamed particles are filled in a molding die provided with the above-mentioned annular frame member, and in-mold molding is performed by steam heating, and the foam core and the annular frame member are integrated into a sheet core. The material was obtained. The obtained sheet core has a substantially rectangular shape when viewed from the top, and is formed with recesses that form two occupant seats side by side in the longitudinal direction. Further, a thinned portion 2b is formed in the rear in accordance with the crank shape 3c of the annular frame member.

  Next, immediately after taking out the sheet core material 1 from the mold (within 180 seconds), a slit 40, a slit 41, a slit 42, and a slit 43 were formed using a cutter knife as shown in FIG. The slit 40 was formed in a substantially central part in the longitudinal direction from the surface side (seat surface side) to a depth of 10 mm above the annular frame member along the short direction.

  In addition, the slits 41 and 42 are provided at the inner position of the annular frame member 3 embedded in front and side of the occupant seating portion from the back surface side (opposite the seating surface) along the annular frame member 3. It was left-right symmetrically formed in a substantially L shape, leaving a side thickness of 15 mm. The lengths of the substantially L-shaped longitudinal piece 42 and the short-sided piece 41 are 100% of the length of the foamed particle molded body 2 in the longitudinal direction. Is formed in the range over 29%, and when the length in the short direction of the foamed particle molded body 2 is 100%, the piece 41 in the short direction of the substantially L-shaped slit is formed in the range over 44%. .

  The slits 43 are formed symmetrically at positions where the annular frame member 3 is embedded at the position where the annular frame member 3 is embedded in the thick portion. Moreover, the depth of the slit 43 was formed at a depth of 10 mm above the annular frame member 3 from the surface side (seat surface side), and the length was formed at a length of 200 mm across the annular frame member 3.

After forming the slits in the composite molded body, curing was performed in an atmosphere at 60 ° C. for 12 hours, and further curing was performed in an atmosphere at 23 ° C. for 1 week. The maximum length in the longitudinal direction of the sheet core after curing is 1210 mm, the maximum length in the short direction is 500 mm, and the thickness of the recess is 20 to 25 mm, and the thickness exists in the front and both sides. The thickness of the meat part was 130-140 mm. Moreover, the bulk density of the expanded particle molded body part after curing was 25 kg / m ³ , and the porosity was 30% by volume.

The bulk density and porosity of the obtained sheet core material were measured by the following methods. A rectangular parallelepiped cut sample of 25 mm × 25 mm × 100 mm was cut out at 10 locations randomly selected from the foamed particle molded body 2 after curing. The cut sample was cut out so as not to have a skin surface. While calculating the bulk volume V (cm < ³ >) of the cut sample from the external dimension, the mass (g) of the cut sample was measured, respectively. Then, M / V is calculated by dividing the cut sample mass M (g) by the cut sample bulk volume V (cm ³ ), and the M / V value calculated for each cut sample is arithmetically averaged. The bulk density of the expanded particle molded body 2 was determined. In addition, the volume I (excluding the void portion of the cut sample by subtracting the volume of ethanol before the cut sample is submerged in ethanol from the total volume of ethanol and the cut sample when the cut sample is submerged in ethanol) cm ³ ) was determined. Then, based on the value of volume H (= volume V) and the value of volume I, the porosity is calculated as a volume ratio by the following (Equation 1), the value of the porosity calculated for each cut sample is arithmetically averaged, The porosity of the foamed particle molded body 2 was used.
Porosity (volume%) = [(HI) / H] × 100 (Formula 1)
Table 1 shows the bulk density and porosity of the sheet core obtained by the above method.

(Comparative Example 1)
Except that polypropylene resin foam particles having no through-holes (bulk density 25 kg / m ³ , average particle mass 1 mg, L / D = 1.0) were used as the raw material foam particles, and no slit was formed. The sheet core material of Comparative Example 1 was molded under the same conditions as in Example 1.
(Comparative Example 2)
The same conditions as in Example 1 except that polypropylene resin foam particles having no through-holes (bulk density 25 kg / m ³ , average particle mass 1 mg, L / D = 1.0) were used as the foam particles of the raw material. The sheet core material of Comparative Example 2 was manufactured.

(Measurement method of warpage)
The sheet cores of Example 1 and Comparative Examples 1 and 2 manufactured under the above conditions were placed on the inspection jig with the seat surface side up, and at the positions A to D shown in FIG. The displacement (mm) from the position was measured. The case where the position is higher than the reference position is “+”, and the case where the position is lower is “−”. Table 1 shows the arithmetic average values of the measurement results of Examples and Comparative Examples 1 and 2.

  From Table 1, Example 1 molded using multi-layer expanded particles having a through-hole in the core layer as a raw material is a product of Comparative Example 1 and 2 using expanded particles having no through-hole as a raw material. It was found that the amount of deformation was small, the warpage of the foamed particle molded body was reduced, and the quality was excellent. Moreover, it turned out that the comparative example 1 which did not provide the slit has a large warp and inferior in quality compared with Example 1 and the comparative example 2 which provided the slit.

  From the above results, the sheet core material of the present invention is a sheet core material that is lightweight, has little warpage, and is extremely excellent in commercial value by forming slits under specific conditions using expanded particles having through holes. It was confirmed that there was.

DESCRIPTION OF SYMBOLS 1 Seat cushion core material for vehicles 2 Thermoplastic resin foam particle molding 20 Plastic resin foam particle (single layer)
21 Expanded plastic resin particles (multilayer)
3 Ring frame member 4 Slit

Claims (9)

A seat cushion core material for a vehicle comprising a composite molded body of a thermoplastic resin expanded particle molded body and an annular frame member embedded by insert molding at a peripheral portion of the thermoplastic resin expanded particle molded body,
The thermoplastic resin expanded particle molded body is a fusion product of thermoplastic resin expanded particles having through holes,
The thermoplastic resin foamed particle molded body has a slit formed to alleviate unequal shrinkage due to molding shrinkage.   The vehicle seat cushion core material according to claim 1, wherein the annular frame member is a metal annular wire frame member having an average diameter of 2 to 5 mm. The vehicular seat cushion core material according to claim 1 or 2, wherein the thermoplastic resin foamed particle molded body has a bulk density of 10 to 90 kg / m ³ and a porosity of 10 to 40% by volume. .   The vehicle seat cushion core according to any one of claims 1 to 3, wherein an average diameter of through-holes of the expanded particles constituting the thermoplastic resin expanded particle molded body is 1 to 7 mm. Wood.   The vehicle seat cushion core material according to any one of claims 1 to 4, wherein both side ends of the slit are positioned inward of the annular frame member.   The vehicle seat cushion core material has a substantially rectangular shape in a top view having a long side and a short side, and the thermoplastic resin foam particle molded body is divided along the short direction of the vehicle seat cushion core material. The vehicle seat cushion core material according to any one of claims 1 to 5, wherein the vehicle seat cushion core material comprises a plurality of foamed particle molded bodies.   The thermoplastic resin foamed particle molded body is composed of a plurality of foamed particle molded bodies that are divided along the short direction of the core material at a position that equally divides the longitudinal direction of the vehicle seat cushion core material. The vehicle seat cushion core material according to any one of claims 1 to 6, wherein the vehicle seat cushion core material is provided.   The vehicle seat cushion core material has a substantially rectangular shape in a top view having a long side and a short side, and the thermoplastic resin foamed particle molded body leaves one or two or more connecting portions, and the vehicle seat cushion core The vehicle seat cushion core material according to any one of claims 1 to 7, wherein the vehicle seat cushion core material is divided along a short direction of the material. The vehicle seat cushion core material according to claim 8, wherein the connecting portion is deformable so as to allow relative movement due to molding shrinkage of the thermoplastic resin foam particle molded body.

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