JP7656181B2 - panel - Google Patents

Description

The present invention relates to a panel that can be used as a luggage board or the like that is installed in the trunk of a vehicle.

Patent document 1 discloses a panel constructed by attaching thin plate-shaped facing materials to a core material.

JP 2016-7900 A

Panels such as those described in Patent Document 1 have excellent strength, but when the inventors conducted a detailed study of the strength of the panels, they found that the panels are prone to buckling deformation, in which the panels bend, when a localized load is applied to the surface material.

The present invention was made in consideration of these circumstances, and provides a panel in which the occurrence of buckling deformation is suppressed.

According to the present invention, there is provided a panel comprising a core material and first and second face materials, the core material being sandwiched between the first and second face materials, the core material having a thickness of 15 to 25 mm, the first and second face materials being bonded to the core material, and a panel strength index defined as the average face material strength index x (10% compressive stress [MPa] of the core material) of ^0.7 or more, where (Young 's modulus of the first face material [Gpa ] ) x (thickness of the first face material [mm]) ² is the first face material strength index, (Young's modulus of the second face material [Gpa]) x (thickness of the second face material [mm])2 is the second face material strength index, and the average of the first and second face material strength indices is the average face material strength index.

After extensive research, the inventors discovered that buckling deformation occurs when a panel is subjected to a local load, resulting in localized deformation of the panel. Based on this knowledge, they discovered that the occurrence of buckling deformation can be effectively suppressed by setting the panel strength index, which correlates with the local strength of the panel, to 0.7 or more, which led to the completion of the present invention.

Various embodiments of the present invention will be described below. The embodiments described below can be combined with each other.
Preferably, the panel is the above-described panel, wherein the panel strength index is 5.0 or less.
Preferably, in the above-described panel, the panel has a basis weight of 3000 g/ ^m2 or less.

FIG. 1A is a perspective view of a panel 1 according to one embodiment of the present invention, FIG. 1B is an enlarged view of an end face in region B in FIG. 1A, and FIG. 1C is a view in which only the core material 2 is extracted from FIG. 1B.

The following describes the embodiments of the present invention. The various features shown in the following embodiments can be combined with each other. In addition, each feature can be an invention independently.

1. First embodiment 1-1. Structure of panel 1 As shown in Fig. 1, a panel 1 according to one embodiment of the present invention includes a core material 2 and first and second face materials 3a, 3b. The core material 2 is sandwiched between the face materials 3a, 3b. The panel 1 preferably has a substantially rectangular parallelepiped shape. The panel 1 can be used as a luggage board or the like to be installed in the luggage compartment of a vehicle.

Let L1 be the length of panel 1 in the first direction, L2 be the length in the second direction perpendicular to the first direction, and L1 ≧ L2. L1 is, for example, 600 to 1200 mm, specifically, for example, 600, 700, 800, 900, 1000, 1100, 1200 mm, and may be within a range between any two of the numerical values exemplified here. L1 is, for example, 300 to 1200 mm, specifically, for example, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200 mm, and may be within a range between any two of the numerical values exemplified here. The value of L2/L1 is, for example, 0.3 to 1, specifically, for example, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, and may be within a range between any two of the numerical values exemplified here.

The basis weight (mass per unit area) of the panel 1 is preferably 3000 g/ ^m2 or less from the viewpoint of reducing the weight of the panel ^1. This basis weight is, for example, 1500 to 3000 g/ ^m2 , specifically, for example, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500, 2600, 2700, 2800, 2900, 3000 g/m2, and may be within a range between any two of the numerical values exemplified here.

The core material 2 is preferably a plate-shaped member. The thickness of the core material 2 is 15 to 25 mm, preferably 18 to 22 mm. If the core material 2 is too thin, the overall deflection of the panel 1 becomes too large. On the other hand, if the core material 2 is too thick, the weight of the panel 1 becomes too large. Specifically, the thickness is, for example, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 mm, and may be within a range between any two of the numerical values exemplified here. The thickness of the core material 2 means the distance at the portion where the distance between the first and second main surfaces 2a and 2b of the core material 2 facing each other is the largest. The core material 2 is preferably provided with a recess, and the surface materials 3a and 3b are fixed within the recess. This prevents the surface materials 3a and 3b from peeling off the core material 2.

The core material 2 may be a foamed or non-foamed body. The core material 2 may also be a hollow or solid body. It is preferable to form the core material 2 by molding using a mold. In this case, the core material 2 can be formed into the desired shape before the panel 1 is manufactured, and therefore has excellent handleability. In addition, the core material 2 can be shaped to match the desired panel shape, and therefore a product with an optimized shape can be obtained.

Examples of the core material 2 include a bead foam molded body obtained by bead foam molding, a foamed or non-foamed sheet molded body obtained by imparting a concave and convex shape to a single foamed or non-foamed resin sheet, and a foamed or non-foamed hollow molded body obtained by molding a foamed or non-foamed cylindrical parison or two resin sheets.

The bead foam can be made of, for example, expanded polystyrene, expanded acrylonitrile styrene, expanded polypropylene, etc., and its expansion ratio is, for example, 20 to 50 times, specifically, for example, 20, 25, 30, 35, 40, 45, 50 times, or may be within a range between any two of the numerical values exemplified here.

The foamed parison or foamed resin sheet can be made of a polyolefin such as polyethylene or polypropylene, and the foaming ratio of a molded article using this is, for example, 1.1 to 8 times, specifically, for example, 1.1, 1.5, 2, 3, 4, 5, 6, 7, or 8, and may be within a range between any two of the numerical values exemplified here.

The 10% compressive stress of the core material 2 is, for example, 0.1 to 1.0 MPa. If this value is too small, buckling deformation is likely to occur, and if this value is too large, the weight of the panel 1 is likely to become excessive. Specific examples of this value are 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, and 1.00 MPa, and may be within a range between any two of the numerical values exemplified here. The 10% compressive stress of the core material 2 can be measured in accordance with JIS K 7220.

The basis weight of the core material 2 is, for example, 400 to 1000 g/ ^m2 , specifically, for example, 400, 500, 600, 700, 800, 900, or 1000 g/ ^m2 , and may be within a range between any two of the numerical values exemplified here.

The face materials 3a and 3b are plate-shaped members, and are bonded to the main surfaces 2a and 2b of the core material 2. The face materials 3a and 3b can be made of a material with a higher rigidity per unit thickness than the core material 2, such as metal (aluminum, iron, etc.) or fiber-reinforced resin. The thickness of each of the face materials 3a and 3b is, for example, 0.05 to 1 mm, and preferably 0.08 to 0.5 mm. Specifically, the thickness may be, for example, 0.05, 0.08, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.60, 0.70, 0.80, 0.90, or 1.00 m, or may be within a range between any two of the numerical values exemplified here. In this specification, values such as thickness and depth refer to average values unless otherwise specified.

The basis weight of each of the face materials 3a, 3b is, for example, 400 to 1000 g/ ^m2 , specifically, for example, 400, 500, 600, 700, 800, 900, 1000 g/ ^m2 , and may be within a range between any two of the numerical values exemplified here.

The facing materials 3a and 3b can be bonded to the core material 2 via the adhesive layers 6a and 6b, respectively. Examples of adhesives constituting the adhesive layers 6a and 6b include urethane adhesives and olefin adhesives, and one-liquid reactive urethane adhesives are preferred. The thickness of each of the adhesive layers 6a and 6b is, for example, 0.01 to 0.5 mm, specifically, for example, 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, and 0.5 mm, and may be within a range between any two of the numerical values exemplified here. The basis weight of each of the adhesive layers 6a and 6b is, for example, 10 to 100 g/m ² , specifically, for example, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 g/m ² , and may be within a range between any two of the numerical values exemplified here.

If (Young's modulus of first panel 3a [ Gpa ]) × (thickness of first panel 3a [mm]) ² is the first panel strength index, (Young's modulus of second panel 3b [ Gpa ]) × (thickness of second panel 3b [mm]) ² is the second panel strength index, and the average of the first and second panel strength indices is the average panel strength index, then the panel strength index defined as the average panel strength index × (10% compressive stress of core material [MPa]) is 0.7 or more.

The panel strength index is an index showing the strength of the panel 3a, 3b. The first and second panel strength indexes and the average panel strength index are each preferably 1.5 or more and 10 or less. If this value is too small, buckling deformation is likely to occur, and if this value is too large, the weight of the panel 1 is likely to become excessive. Specific examples of this value are 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, and 10.0, and may be within a range between any two of the numerical values exemplified here.

The panel strength index is an index showing the strength that correlates with the local strength of panel 1. It is preferable that the panel strength index is 0.7 or more and 5.0 or less. If this value is too small, buckling deformation is likely to occur, and if this value is too large, the weight of panel 1 is likely to become excessive. Specifically, this value may be, for example, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, or 5.0, or may be within a range between any two of the values exemplified here.

When two edges of panel 1 at both ends in the first direction are supported and a load is applied to the center of panel 1 in the first direction with a presser having a contact surface diameter of 50 mm, the buckling load (the minimum load at which buckling deformation occurs) is preferably 40 kg or more and preferably 300 kg or less. If this value is too small, buckling deformation is more likely to occur, and if this value is too large, the weight of panel 1 is likely to be excessive. Specific examples of this value are 40, 50, 60, 70, 80, 90, 100, 150, 200, 250, and 300 kg, and may be within a range between any two of the numerical values exemplified here.

1-2. Manufacturing Method of Panel 1 The panel 1 can be manufactured by applying an adhesive onto the core material 2 (for example, by spray application or bead application), and then pressing the face materials 3 a and 3 b onto the core material 2 .

2. Other embodiments If necessary, a skin material may be provided so as to cover the core material 2 and the face materials 3a, 3b. This improves the appearance and prevents the face materials 3a, 3b from peeling off from the core material 2. In one example, the skin material is a nonwoven fabric, and can be adhered to the face materials 3a, 3b and the core material 2 via an adhesive layer.

A panel 1 having a planar shape of 1000 mm x 450 mm was manufactured using the core material 2 and the face materials 3a and 3b shown in Table 1. A one-liquid reactive urethane adhesive was used as the adhesive for bonding the core material 2 and the face materials 3a and 3b, and was applied to a thickness of 60 g/ ^m2 . In the examples and comparative examples in Table 1, the material and thickness of the face materials 3a and 3b were the same. Al5052 was used as the Al, and SUS304 was used as the SUS. The core material 2 was manufactured using Heatpole GR (JSP Corporation).

With both ends of the panel 1 in the longitudinal direction supported, a load was applied to the center of the panel 1 in the longitudinal direction using a presser with a contact surface diameter of 50 mm. The load was increased by 10 kg at a time, and the load at which buckling deformation occurred was taken as the buckling load. The results are shown in Table 1.

As shown in Table 1, buckling deformation was unlikely to occur in all examples where the panel strength index was 0.7 or higher.

1: Panel 2: Core material 2a: First main surface 2b: Second main surface 3a: First surface material 3b: Second surface material 6a: Adhesive layer 6b: Adhesive layer

Claims (2)

A panel comprising a core material and first and second face materials,
The core material is sandwiched between first and second face materials,
The core material has a thickness of 15 to 25 mm;
the first and second face materials are bonded to the core material;
(Young's modulus of the first surface material [GPa]) × (thickness of the first surface material [mm]) ² is defined as the first surface material strength index,
(Young's modulus of the second surface material [GPa]) × (thickness of the second surface material [mm]) ² is defined as the second surface material strength index,
If the average value of the first and second face material strength indices is taken as the average face material strength index,
A panel having a panel strength index, defined as the average surface material strength index x (10% compressive stress [MPa] of the core material), of 0.7 or more and 5.0 or less . 2. The panel of claim 1 ,
The panel has a basis weight of 3000 g/m2 ^{or less} .