U.S. patent application number 17/093459 was filed with the patent office on 2022-01-27 for automotive crash pad and manufacturing method thereof.
The applicant listed for this patent is HYUNDAI MOBIS Co., LTD.. Invention is credited to Do Hyung KIM, Chang Wan SON.
Application Number | 20220024401 17/093459 |
Document ID | / |
Family ID | |
Filed Date | 2022-01-27 |
United States Patent
Application |
20220024401 |
Kind Code |
A1 |
KIM; Do Hyung ; et
al. |
January 27, 2022 |
AUTOMOTIVE CRASH PAD AND MANUFACTURING METHOD THEREOF
Abstract
An automotive crash pad and a method for manufacturing the same.
The automotive crash pad includes: a skin layer forming the outer
surface of the crash pad including an airbag module; a fiber-based
layer formed on the lower surface of the skin layer; a cushion
layer formed on the lower surface of the fiber-based layer and
including slab foam; and a core layer formed on the lower surface
of the cushion layer, wherein a laminate of the skin layer and the
fiber-based layer has a tensile strength in transverse direction
(TD) of 5 to 50 kgf/3 cm and an elongation at break in transverse
direction (TD) of 40 to 220%.
Inventors: |
KIM; Do Hyung; (Yongin-si,
KR) ; SON; Chang Wan; (Yongin-si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HYUNDAI MOBIS Co., LTD. |
Seoul |
|
KR |
|
|
Appl. No.: |
17/093459 |
Filed: |
November 9, 2020 |
International
Class: |
B60R 21/045 20060101
B60R021/045; B60R 21/205 20060101 B60R021/205; B60R 21/215 20060101
B60R021/215; B32B 5/20 20060101 B32B005/20; B32B 7/12 20060101
B32B007/12; B32B 5/02 20060101 B32B005/02; B32B 5/24 20060101
B32B005/24; B32B 27/06 20060101 B32B027/06; B32B 27/12 20060101
B32B027/12; B32B 27/40 20060101 B32B027/40 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 21, 2020 |
KR |
10-2020-0090302 |
Claims
1. An automotive crash pad comprising: a skin layer forming an
outer surface of the crash pad including an airbag module; a
fiber-based layer formed on a lower surface of the skin layer; a
cushion layer formed on a lower surface of the fiber-based layer
and comprising slab foam; and a core layer formed on a lower
surface of the cushion layer, wherein a laminate of the skin layer
and the fiber-based layer has a tensile strength in a transverse
direction (TD) of 5 to 50 kgf/3 cm and an elongation at break in a
transverse direction (TD) of 40 to 220%.
2. The automotive crash pad of claim 1, wherein the skin layer has
a thickness of 0.1 to 0.7 mm, the fiber-based layer has a thickness
of 0.3 to 0.7 mm, the cushion layer has a thickness of 1 to 10 mm,
and the core layer has a thickness of 1 to 6 mm.
3. The automotive crash pad of claim 1, wherein the cushion layer
has a density of 0.05 to 5 g/cm.sup.3, a porosity of 5 to 80%, a
tensile strength of 3 to 20 kgf/cm.sup.2, an elongation of 50 to
200%, and a tearing strength of 0.2 to 1.5 kgf/cm.
4. The automotive crash pad of claim 1, wherein the skin layer
comprises one or more of thermoplastic polyurethane, thermoplastic
polyolefin, polyvinyl chloride, and thermosetting polyurethane.
5. The automotive crash pad of claim 1, wherein the skin layer is
formed using a skin layer composition comprising 65 to 75 wt % of a
polyol compound, 15 to 25 wt % of an isocyanate-based curing agent,
and 10 to 15 wt % of a chain extender.
6. The automotive crash pad of claim 1, wherein the slab foam is
formed by foaming a first composition comprising 40 to 75 wt % of a
polyol compound, 15 to 45 wt % of an isocyanate-based curing agent,
and 1 to 15 wt % of a foaming agent.
7. The automotive crash pad of claim 1, further comprising one or
more of a first adhesive layer formed between the fiber-based layer
and the cushion layer, and a second adhesive layer formed between
the cushion layer and the core layer.
8. The automotive crash pad of claim 1, further comprising a
surface treatment layer formed on at least a portion of the skin
layer.
9. The automotive crash pad of claim 1, wherein the fiber-based
layer has a density of 0.22 to 0.27 g/cm.sup.3 and is in the form
of knitted or nonwoven fabric.
10. A method for manufacturing an automotive crash pad, the
automotive crash pad including: a skin layer forming an outer
surface of the crash pad including an airbag module; a fiber-based
layer formed on a lower surface of the skin layer; a cushion layer
formed on a lower surface of the fiber-based layer and including
slab foam; and a core layer formed on a lower surface of the
cushion layer, the method comprising: preparing an intermediate by
laminating the cushion layer and the core layer together; and
laminating the fiber-based layer and the skin layer onto the
intermediate, wherein a laminate of the skin layer and the
fiber-based layer has a tensile strength in transverse direction
(TD) of 5 to 50 kgf/3 cm and an elongation at break in transverse
direction (TD) of 40 to 220%.
11. The method of claim 10, wherein the laminating of the
fiber-based layer and the skin layer onto the intermediate includes
forming a first adhesive layer between the fiber-based layer and
the cushion layer.
12. The method of claim 10, wherein the preparing of the
intermediate includes forming a second adhesive layer between the
cushion layer and the core layer.
13. The method of claim 10, further comprising, after the
laminating of the fiber-based layer and the skin layer onto the
intermediate covering the fiber-based layer, the cushion layer, and
the core layer with the skin layer.
14. The method of claim 10, wherein the slab foam is formed by
foaming a first composition comprising a polyol compound, an
isocyanate-based curing agent, and a foaming agent.
15. The method of claim 10, wherein the skin layer is not subjected
to a skiving or scoring process.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority from and the benefit of
Korean Patent Application No.10-2020-0090302, filed on Jul. 21,
2020, which is hereby incorporated by reference for all purposes as
if set forth herein.
BACKGROUND
Field
[0002] Exemplary embodiments of the present disclosure relate to an
automotive crash pad and a manufacturing method thereof.
Discussion of the Background
[0003] A crash pad, also called an instrument panel, is an
automotive interior part that is attached to the lower end of the
front glass of the driver's seat. An airbag is mounted in the crash
pad. The airbag functions to protect the occupant's life from an
external shock by deployment through the seam line of the crash pad
when a crash occurs. Thus, the airbag is a very important part in
terms of design, convenience and stability.
[0004] FIG. 1 illustrates a conventional automotive crash pad, and
FIG. 2 illustrates a conventional crash pad. Referring to FIGS. 1
and 2, a crash pad 100 includes a core layer 1, a cushion layer 2
formed on the surface of the core layer 1, and a skin layer 3
formed on the surface of the cushion layer 2. The core layer, the
cushion layer and the skin layer are adhered together using an
aqueous adhesive.
[0005] Meanwhile, in recent years, as there has been a demand for
luxury cars, the automotive crash pad has also been required to
have excellent sensitivity, tactile sensation and appearance. This
high-quality crash pad may include a skin layer manufactured using
natural leather. However, natural leather has problems in that it
is expensive and the quality control thereof is difficult, so that
deformation or surface damage of the natural leather easily occurs.
Therefore, there is an urgent need for the development of
artificial leather, which exhibits sensitivity, tactile sensation
and appearance similar to those of natural leather and also has
excellent mechanical properties, and a crash pad using the
same.
[0006] Here, the skin layer 3 is formed using the material and
coating agent that may have the appearance and feel of real leather
to emphasize design and aesthetic quality. Referring to FIG. 2, a
skin layer-weakening portion 4 for deployment of the airbag
(passenger airbag (PAB)) is formed on the skin layer 3 by
performing a skin layer-weakening process on the skin layer 3.
Specifically, the airbag deployment portion of the skin layer,
which corresponds to the airbag deployment portion of the crash
pad, is processed by skiving or skin scoring to reduce the
thickness of the skin layer.
[0007] However, when the crash pad is manufactured by performing
the skin layer-weakening process, problems arise in that material
and process costs increase, resulting in decreases in productivity
and economic efficiency, and the labor cost and work time
associated with the skin layer-weakening process are added.
[0008] Background art related to the present disclosure includes
Korean Patent Application Publication No. 2015-0135708 (published
on Dec. 3, 2015; entitled "Method for Manufacturing Crash Pad
Skin").
[0009] The above information disclosed in this Background section
is only for enhancement of understanding of the background of the
invention and, therefore, it may contain information that does not
constitute prior art.
SUMMARY
[0010] Exemplary embodiments of the present invention provide an
automotive crash pad which has excellent airbag deployment
performance, and thus, makes it possible to eliminate a skin
layer-weakening process when forming a skin layer.
[0011] Another object of the present disclosure is to provide an
automotive crash pad having excellent economic efficiency due to
process simplification and cost reduction.
[0012] Still another object of the present disclosure is to provide
an automotive crash pad having excellent sensitivity properties,
such as appearance and tactile sensation.
[0013] Yet another object of the present disclosure is to provide
an automotive crash pad having excellent lightweight and mechanical
properties.
[0014] Still yet another object of the present disclosure is to
provide an automotive crash pad having excellent adhesion between a
skin layer and a slab foam layer.
[0015] A further object of the present disclosure is to provide a
method for manufacturing the automotive crash pad.
[0016] Additional features of the invention will be set forth in
the description which follows, and in part will be apparent from
the description, or may be learned by practice of the
invention.
[0017] An exemplary embodiment of the present invention provides an
automotive crash pad including: a skin layer forming the outer
surface of the crash pad including an airbag module; a fiber-based
layer formed on the lower surface of the skin layer; a cushion
layer formed on the lower surface of the fiber-based layer and
including slab foam; and a core layer formed on to the lower
surface of the cushion layer, wherein a laminate of the skin layer
and the fiber-based layer has a tensile strength in transverse
direction (TD) of 5 to 50 kgf/3 cm and an elongation at break in
transverse direction (TD) of 40 to 220%.
[0018] The skin layer may have a thickness of 0.1 to 0.7 mm, the
fiber-based layer may have a thickness of 0.3 to 0.7 mm, the
cushion layer may have a thickness of 1 to 10 mm, and the core
layer may have a thickness of 1 to 6 mm.
[0019] The cushion layer may have a density of 0.05 to 5 g/cm3, a
porosity of 5 to 80%, a tensile strength of 3 to 20 kgf/cm2, an
elongation of 50 to 200%, and a tearing strength of 0.2 to 1.5
kgf/cm.
[0020] The skin layer may include one or more of thermoplastic
polyurethane, thermoplastic polyolefin, polyvinyl chloride, and
thermosetting polyurethane.
[0021] The skin layer may be formed using a skin layer composition
including 65 to 75 wt % of a polyol compound, 15 to 25 wt % of an
isocyanate-based curing agent, and 10 to 15 wt % of a chain
extender.
[0022] The slab foam may be formed by foaming a first composition
including 40 to 75 wt % of a polyol compound, 15 to 45 wt % of an
isocyanate-based curing agent, and 1 to 15 wt % of a foaming
agent.
[0023] The crash pad may further include one or more of a first
adhesive layer formed between the fiber-based layer and the cushion
layer, and a second adhesive layer formed between the cushion layer
and the core layer.
[0024] The crash pad may further include a surface treatment layer
formed on at least a portion of the skin layer.
[0025] The fiber-based layer may have a density of 0.22 to 0.27
g/cm3 and may be in the form of knitted or nonwoven fabric.
[0026] Another exemplary embodiment of the present invention
provides a method for manufacturing an automotive crash pad, the
automotive crash pad including: a skin layer forming the outer
surface of the crash pad including an airbag module; a fiber-based
layer formed on the lower surface of the skin layer; a cushion
layer formed on the lower surface of the fiber-based layer and
including slab foam; and a core layer formed on the lower surface
of the cushion layer, the method including steps of: preparing an
intermediate by laminating the cushion layer and the core layer
together; and laminating the fiber-based layer and the skin layer
onto the intermediate, wherein a laminate of the skin layer and the
fiber-based layer has a tensile strength in transverse direction
(TD) of 5 to 50 kgf/3 cm and an elongation at break in transverse
direction (TD) of 40 to 220%.
[0027] The laminating in the step of laminating the fiber-based
layer and the skin layer onto the intermediate may be achieved by
forming a first adhesive layer between the fiber-based layer and
the cushion layer.
[0028] The laminating in the step of preparing the intermediate may
be achieved by forming a second adhesive layer between the cushion
layer and the core layer.
[0029] The method may further include a step of covering the
fiber-based layer, the cushion layer and the core layer with the
skin layer, after the step of laminating the fiber-based layer and
the skin layer onto the intermediate.
[0030] The slab foam may be formed by foaming a first composition
including a polyol compound, an isocyanate-based curing agent, and
a foaming agent.
[0031] The skin layer may not be subjected to a skiving or scoring
process.
[0032] The automotive crash pad according to the present disclosure
allows the airbag to be quickly deployed in the event of an
external shock, even when a skin layer-weakening process, such as
skiving or scoring, is eliminated. In addition, the automotive
crash pad may have a good tear shape, and have excellent
productivity and economic efficiency due to process simplification
and cost reduction. Furthermore, the automotive crash pad may have
excellent adhesion between the skin layer and the slab foam layer,
and may have excellent sensitivity properties, such as appearance
and soft tactile sensation, as a result of reducing the thickness
of the skin layer and applying the slab foam layer.
[0033] It is to be understood that both the foregoing general
description and the following detailed description are exemplary
and explanatory and are intended to provide further explanation of
the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] The accompanying drawings, which are included to provide a
further understanding of the invention and are incorporated in and
constitute a part of this specification, to illustrate embodiments
of the invention, and together with the description serve to
explain the principles of the invention.
[0035] FIG. 1 illustrates a conventional automotive crash pad.
[0036] FIG. 2 illustrates the conventional crash pad.
[0037] FIG. 3 illustrates a crash pad according to one embodiment
of the present disclosure.
[0038] FIG. 4 illustrates a crash pad according to another
embodiment of the present disclosure.
[0039] FIG. 5 illustrates a method for manufacturing an automotive
crash pad according to one embodiment of the present
disclosure.
[0040] FIG. 6 shows the cross-section of a crash pad of Example
1.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0041] The invention is described more fully hereinafter with
reference to the accompanying drawings, in which embodiments of the
invention are shown. This invention may, however, be embodied in
many different forms and should not be construed as limited to the
embodiments set forth herein. Rather, these embodiments are
provided so that this disclosure is thorough, and will fully convey
the scope of the invention to those skilled in the art. Like
reference numerals in the drawings denote like elements.
[0042] In the following description, the detailed description of
related publicly-known technology or configuration will be omitted
when it may unnecessarily obscure the subject matter of the present
disclosure.
[0043] In addition, the terms used in the following description are
terms defined considering the functions in the present disclosure,
and may be changed in accordance with the option of a user or
operator or a usual practice. Accordingly, the definition of the
terms should be made based on the contents throughout the present
specification.
[0044] In the present specification, the terms "upper portion" and
"lower portion" are defined based on the drawings, and depending on
the point of view, "upper portion" may be changed to "lower
portion" and "lower portion" may be changed to "upper portion". In
addition, in the present disclosure, when one element is referred
to as being "on" another element, it refers to not only a case
where the element is formed directly located "on" the other element
but also a case where an additional element exists between these
elements.
[0045] Automotive Crash Pad
[0046] One aspect of the present disclosure is directed to an
automotive crash pad. FIG. 3 illustrates a crash pad according to
one embodiment of the present disclosure. Referring to FIG. 3, an
automotive crash pad 200 includes: a skin layer 40 forming the
outer surface of the crash pad including an airbag module; a
fiber-based layer 30 formed on the lower surface of the skin layer
40; a cushion layer 20 formed on the lower surface of the
fiber-based layer 30 and including slab foam; and a core layer 10
formed on the lower surface of the cushion layer 20.
[0047] A laminate of the skin layer and the fiber-based layer has a
tensile strength in transverse direction (TD) of 5 to 50 kgf/3 cm
and an elongation at break in transverse direction (TD) of 40 to
220%.
[0048] Skin Layer
[0049] The skin layer 40 forms the appearance of the crash pad 200,
and may give a user sensitivity, such as tactile sensation and
cushion feeling.
[0050] In one embodiment, the skin layer 40 may have a thickness of
0.1 to 0.7 mm. Within this thickness range, the airbag may be
easily deployed through the skin layer in the event of an external
shock, even when the skin layer is not subjected to a skin
layer-weakening process such as scoring or skiving, and the skin
layer may have excellent mechanical properties. For example, the
skin layer may have a thickness of 0.1 to 0.4 mm. For example, the
skin layer 40 may have a thickness of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6
or 0.7 mm.
[0051] In one embodiment, a laminate of the skin layer and the
fiber-based layer may have a tensile strength in transverse
direction (TD) of 5 to 50 kgf/3 cm and an elongation at break in
transverse direction (TD) of 40 to 220%. For example, a laminate of
the skin layer having a thickness of 0.1 to 0.7 mm and the
fiber-based layer having a thickness of 0.01 to 1 mm may have a
tensile strength in transverse direction (TD) of 5 to 50 kgf/3 cm
and an elongation at break in transverse direction (TD) of 40 to
220%, as measured at a test speed of 200 mm/min using an Instron
UTM instrument according to Hyundai Motors Specification
MS300-31.
[0052] If the laminate of the skin layer and the fiber-based layer
has the tensile strength in transverse direction (TD) of less than
5 kgf/3 cm, the laminate may be easily damaged by an external shock
because the strength thereof is excessively low, and if the
laminate has a tensile strength in transverse direction of greater
than 50 kgf/3 cm, the airbag cannot be deployed unless the skin
layer is subjected to the skiving or scoring process. For example,
the laminate of the skin layer and the fiber-based layer may have
the tensile strength in transverse direction (TD) of 5, 6, 7, 8, 9,
10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26,
27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43,
44, 45, 46, 47, 48, 49 or 50 kgf/3 cm.
[0053] If the laminate of the skin layer and the fiber-based layer
has the elongation at break in transvers direction (TD) of less
than 40%, the airbag may be difficult to quickly deploy through the
skin layer in the event of an external shock, and if the laminate
has the elongation at break in transverse direction (TD) of greater
than 220%, the deployment shape of the airbag may be poor. For
example, the laminate of the skin layer and the fiber-based layer
may have the elongation at break in transvers direction (TD) of 40,
50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180,
190, 200, 210 or 220%.
[0054] The skin layer may have a tearing strength of 2 to 8 kgf/cm.
Under this condition, the skin layer may have excellent mechanical
properties, and at the same time, the airbag can easily be deployed
even when the skin layer is not subjected to the skiving or scoring
process. For example, the skin layer may have a tearing strength of
2, 3, 4, 5, 6, 7 or 8 kgf/cm.
[0055] In one embodiment, the skin layer may be formed to include
one or more of thermoplastic polyurethane, thermoplastic
polyolefin, polyvinyl chloride and thermosetting polyurethane. For
example, the skin layer may include thermosetting polyurethane.
[0056] In one embodiment, the skin layer may be formed using a skin
layer composition. The skin layer composition may include 65 to 75
wt % of a polyol compound, 15 to 25 wt % of an isocyanate-based
curing agent, and 10 to 15 wt % of a chain extender. Under the
above conditions, it is possible to easily achieve the mechanical
properties of the skin layer targeted by the present
disclosure.
[0057] In one embodiment, the polyol compound may include one or
more of diol, triol, and polymer polyol.
[0058] In one embodiment, the diol may include one or more of
ethylene glycol, diethylene glycol, butanediol and hexanediol.
[0059] In one embodiment, the triol may include one or more of
glycerin, trimethylolpropane, and 1,2,3-hexanetriol.
[0060] In one embodiment, the polymer polyol may include one or
more of polyolefin polyol, polyester polyol, polycaprolactone
polyol, polyether polyol, and polycarbonate polyol.
[0061] In one embodiment, the polyol compound may be included in an
amount of 65 to 75 wt % based on the total weight of the skin layer
composition. Under this condition, the mechanical properties of the
skin layer targeted by the present disclosure may be easily
achieved. For example, the polyol compound may be included in an
amount of 65, 66, 67, 68, 69, 70, 71, 72, 73, 74 or 75 wt %, based
on the total weight of the skin layer composition.
[0062] The isocyanate-based curing agent may react with the polyol
compound to form the skin layer. In one embodiment, the
isocyanate-based curing agent may include one or more of
4,4'-dicyclohexylmethane diisocyanate, 4,4-dimethylphenylmethane
diisocyanate, bis-4-(isocyanate cyclohexyl)methane, hexamethylene
diisocyanate, xylene diisocyanate, p-phenylene diisocyanate,
tolidine diisocyanate, tetramethylene diisocyanate, dimethyl
diisocyanate, trimethyl hexamethylene diisocyanate, phenylene
diisocyanate, and dimethyl diphenyl diisocyanate.
[0063] In one embodiment, the isocyanate-based curing agent may be
included in an amount of 15 to 25 wt % based on the total weight of
the skin layer composition. Under this condition, the mechanical
properties of the skin layer targeted by the present disclosure may
be easily achieved. For example, the isocyanate-based curing agent
may be included in an amount of 15, 16, 17, 18, 19, 20, 21, 22, 23,
24 or 25 wt %, based on the total weight of the skin layer
composition.
[0064] The chain extender may be included for the purpose of
chain-extending or crosslinking the polyurethane formed in the skin
layer to increase the molecular weight of the polyurethane and
improve mechanical properties, heat resistance and chemical
resistance.
[0065] In one embodiment, the chain extender may include one or
more of diol, triol, and amine compounds. For example, the chain
extender may include one or more of ethylene glycol, propylene
glycol, 1,4-butanediol, glycerin, diethanolamine (DEOA), and
triethanolamine (TEOA).
[0066] In one embodiment, the chain extender may be included in an
amount of 10 to 15 wt % based on the total weight of the skin layer
composition. Under this condition, the mechanical properties of the
skin layer targeted by the present disclosure may be easily
achieved. For example, the chain extender may be included in an
amount of 10, 11, 12, 13, 14 or 15 wt %, based on the total weight
of the skin layer composition.
[0067] In one embodiment, the skin layer may not be subjected to a
skiving or scoring process. The crash pad of the present disclosure
allows the airbag to easily be deployed in the event of an external
shock even when the skin layer-weakening process (skiving or
scoring process) is not performed. Thus, under the above-described
conditions, the skin layer-weakening process may be eliminated, and
thus the number of processes can be reduced and excellent economic
efficiency can be obtained.
[0068] Fiber-Based Layer
[0069] The fiber-based layer 30 is included for the purpose of
improving the tactile sensation, cushion feeling and appearance of
the crash pad of the present disclosure. In one embodiment, the
fiber-based layer 30 may include one or more of polyethylene
terephthalate (PET) and polyamide (PA). When the fiber-based layer
is included, the tactile sensation and appearance of the crash pad
of the present disclosure may be excellent.
[0070] In one embodiment, the fiber-based layer 30 may be in the
form of a knitted or nonwoven fabric. For example, it may be in the
form of a knitted fabric. When the fiber-based layer 30 is in this
form, the crash pad may have excellent tactile sensation and
cushion feeling, and the airbag can be easily deployed through the
skin layer in the event of an external shock.
[0071] For example, the fiber-based layer may be in the form of a
knitted fabric including PET fiber, and may have a weight of 150 to
200 g/m2 and a fineness of 20 denier to 500 denier. Under these
conditions, the crash pad may have excellent lightweight
properties, tactile sensation and cushion feeling, and the airbag
can be easily deployed in the event of an external shock.
[0072] In one embodiment, the fiber-based layer 30 may have a
density of 0.22 to 0.27 g/cm3 and a thickness of 0.01 to 1 mm.
within the density and thickness ranges, the crash pad may have
excellent tactile sensation and cushion feeling, the airbag can be
easily deployed through the skin layer in the event of an external
shock, and the fiber-based layer may have excellent mechanical
properties. For example, the fiber-based layer may have a density
of 0.22, 0.23, 0.24, 0.25, 0.26 or 0.27 g/cm3. For example, the
fiber-based layer 30 may have a thickness of 0.3 to 0.7 mm.
[0073] Surface Treatment Layer
[0074] In one embodiment, the crash pad may further include a
surface treatment layer formed on the skin layer. The surface
treatment layer may be included for the purpose of improving
functions such as light stability and antifouling properties while
controlling the gloss of the skin layer and expressing color.
[0075] In one embodiment, the surface treatment layer may include a
polyurethane resin. For another example, the surface treatment
layer may be formed by applying and curing a water-dispersible
polyurethane resin composition. In one embodiment, the
water-dispersible polyurethane resin may include a polyol compound,
a chain extender, an isocyanate-based curing agent, and water, but
is not limited thereto.
[0076] In one embodiment, the thickness of the surface treatment
layer may be 1 to 200 .mu.m. Within this thickness range, the crash
pad may have excellent appearance, light stability and antifouling
properties.
[0077] First Adhesive Layer
[0078] Referring to FIG. 3, the crash pad 200 may further include a
first adhesive layer 50 between the fiber-based layer 30 and the
cushion layer 20. When the first adhesive layer 50 is included,
adhesion between the fiber-based layer and the cushion layer may be
improved.
[0079] The first adhesive layer 50 may include polyurethane. For
example, it may include organic solvent-type polyurethane or
water-dispersible polyurethane. In one embodiment, the first
adhesive layer may be formed using a first adhesive composition.
For example, the first adhesive composition may include a polyol
compound, an isocyanate-based curing agent, and a solvent.
[0080] In one embodiment, the polyol compound may include one or
more of diol, triol and polymer polyol.
[0081] In one embodiment, the diol may include one or more of
ethylene glycol, diethylene glycol, butanediol, and hexanediol.
[0082] In one embodiment, the triol may include one or more of
glycerin, trimethylolpropane, and 1,2,3-hexanetriol.
[0083] In one embodiment, the polymer polyol may include one or
more of polyolefin polyol, polyester polyol, polycaprolactone
polyol, polyether polyol, and polycarbonate polyol.
[0084] The isocyanate-based curing agent may react with the polyol
compound to form the first adhesive layer. In one embodiment, the
isocyanate-based curing agent may include one or more of
4,4'-dicyclohexylmethane diisocyanate, 4,4-dimethylphenylmethane
diisocyanate, bis-4-(isocyanate cyclohexyl)methane, hexamethylene
diisocyanate, xylene diisocyanate, p-phenylene diisocyanate,
tolidine diisocyanate, tetramethylene diisocyanate, dimethyl
diisocyanate, trimethyl hexamethylene diisocyanate, phenylene
diisocyanate, and dimethyl diphenyl diisocyanate.
[0085] In one embodiment, the solvent may include one or more of
water, an alcohol having 1 to 10 carbon atoms, toluene, acetone,
methyl ethyl ketone, dimethylformamide, and cyclohexane.
[0086] In one embodiment, the adhesive strength between a laminate
of the skin layer and the fiber-based layer and the cushion layer
may be 0.3 kgf/cm or more, as measured according to the ISO 813
standard. The adhesive strength may be a result obtained by
measuring the adhesive strength between the skin layer/fiber-based
layer laminate and the cushion layer according to Hyundai-Kia
Motors MS Specification 256-29 (ISO 813 standard; 90.degree.
peeling method; peeling speed: 25 mm/min). If the adhesive strength
is less than 0.3 kgf/cm, the adhesion between the laminate and the
first adhesive layer (cushion layer) may be poor, and the tear
shape of the airbag may be poor. For example, the adhesive strength
may be 0.3 to 1.2 kgf/cm. For example, it may be 0.3, 0.4, 0.5,
0.6, 0.7, 0.8, 0.9, 1, 1.1 or 1.2 kgf/cm.
[0087] In one embodiment, the laminate of the skin layer and the
fiber-based layer may have an adhesive strength of 0.3 kgf/cm or
more to the first adhesive layer, as measured according to the ISO
813 standard. The adhesive strength may be a result obtained by
measuring the adhesive strength between the skin layer/fiber-based
layer laminate and the first adhesive layer according to
Hyundai-Kia Motors MS Specification 256-29 (ISO 813 standard;
90.degree. peeling method; peeling speed: 25 mm/min). If the
adhesive strength is less than 0.3 kgf/cm, the adhesion between the
laminate and the first adhesive layer (cushion layer) may be poor,
and the tear shape of the airbag may be poor. For example, the
adhesive strength may be 0.3 to 1.2 kgf/cm. For example, it may be
0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1 or 1.2 kgf/cm.
[0088] In one embodiment, the thickness of the first adhesive layer
50 may be 30 to 300 .mu.m. Within this thickness range, the first
adhesive layer may have excellent adhesion, and at the same time,
the airbag can be easily deployed through the skin layer in the
event of an external shock.
[0089] Cushion Layer
[0090] The cushion layer functions to secure the physical
properties of the crash pad, such as heat resistance, impact
resistance and light stability, and to impart tactile sensation
such as cushion feeling to the driver and the passenger.
[0091] In one embodiment, the cushion layer includes slab foam.
When the slab foam is included, the cushion layer may have
excellent airbag deployment performance and cushion feeling
compared to a conventional filament layer, and have excellent
economic efficiency because of being cheaper than the conventional
filament layer, and the airbag can be easily deployed in the event
of an external shock while the airbag module is prevented from
damage.
[0092] In one embodiment, the slab foam may be formed by foaming a
first composition including a polyol compound, an isocyanate-based
curing agent and a foaming agent.
[0093] In one embodiment, the polyol compound may include one or
more of diol, triol, and polymer polyol.
[0094] In one embodiment, the diol may include one or more of
ethylene glycol, diethylene glycol, butanediol, and hexanediol.
[0095] In one embodiment, the triol may include one or more of
glycerin, trimethylolpropane, and 1,2,3-hexanetriol.
[0096] In one embodiment, the polymer polyol may include one or
more of polyolefin polyol, polyester polyol, polycaprolactone
polyol, polyether polyol, and polycarbonate polyol.
[0097] In one embodiment, the polyol compound may be included in an
amount of 40 to 75 wt % based on the total weight of the first
composition. When the polyol compound is included in an amount
within the above range, the slab foam may have excellent mechanical
strength. For example, the polyol compound may be included in an
amount of 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53,
54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70,
71, 72, 73, 74 or 75 wt %, based on the total weight of the first
composition.
[0098] The isocyanate-based curing agent may react with the polyol
compound to form the slab foam. In one embodiment, the
isocyanate-based curing agent may include one or more of
4,4'-dicyclohexylmethane diisocyanate, 4,4-dimethylphenylmethane
diisocyanate, bis-4-(isocyanate cyclohexyl)methane, hexamethylene
diisocyanate, xylene diisocyanate, p-phenylene diisocyanate,
tolidine diisocyanate, tetramethylene diisocyanate, dimethyl
diisocyanate, trimethyl hexamethylene diisocyanate, phenylene
diisocyanate, and dimethyl diphenyl diisocyanate.
[0099] In one embodiment, the isocyanate-based curing agent may be
included in an amount of 15 to 45 wt % based on the total weight of
the first composition. When the isocyanate-based curing agent is
included in an amount within this range, the slab foam may have
excellent mechanical strength. For example, the isocyanate-based
curing agent may be included in an amount of 15, 16, 17, 18, 19,
20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36,
37, 38, 39, 40, 41, 42, 43, 44 or 45 wt %, based on the total
weight of the first composition.
[0100] The foaming agent may include one or more of water, butane,
n-pentane, c-pentane, hexane, heptane, chlorofluorocarbon (CFC 11),
hydrogen chlorofluorocarbons (H-CFCs), hydrogen fluorocarbons
(H-FCs), trichlorofluoromethane (Freon 11), chlorodifluoromethane
(R-22), 1,1-dichloro-1-fluoroethane (HCFC-141b), and
1,1,1,3,3-pentafluoropropane (HFC-245fa).
[0101] In one embodiment, the foaming agent may be included in an
amount of 1 to 15 wt % based on the total weight of the first
composition. When the foaming agent is included in an amount within
this range, the slab foam may have excellent mechanical strength.
For example, the foaming agent may be included in an amount of 1,
2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15 wt %, based on the
total weight of the first composition.
[0102] In one embodiment, the cushion layer may have a density of
0.05 to 5 g/cm3 and a porosity of 5 to 80%. Under these conditions,
the crash pad may have excellent lightweight and mechanical
strength properties.
[0103] In one embodiment, the cushion layer may have a tensile
strength of 3 to 20 kgf/cm2, an elongation of 50 to 200% and a
tearing strength of 0.2 to 1.5 kgf/cm, as measured according to
Hyundai Motors Specification MS300-31. Under these tensile
strength, elongation and tearing strength conditions, the cushion
layer may have excellent physical properties, and at the same time,
the air bag can be easily deployed through the cushion layer in the
event of an external shock.
[0104] For example, the cushion layer may have a tensile strength
of 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or
20 kgf/cm2, as measured according to Hyundai Motors Specification
MS300-31, an elongation of 50, 60, 70, 80, 90, 100, 110, 120, 130,
140, 150, 160, 170, 180, 190 or 200%, as measured according to
Hyundai Motors Specification MS300-31, and a tearing strength of
0.2. 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4 or
1.5 kgf/cm, as measured according to Hyundai Motors Specification
MS300-31.
[0105] For example, the cushion layer may have a thickness of 1 to
10 mm. When the cushion layer is formed to have this thickness, the
cushion layer may have excellent physical properties, such as heat
resistance, impact resistance and light stability, and the airbag
deployment performance in the event of an external shock may be
excellent. For another example, the cushion layer may have a
thickness of 1 to 5 mm. For example, the cushion layer may have a
thickness of 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 mm.
[0106] Second Adhesive Layer
[0107] FIG. 4 illustrates a crash pad according to another
embodiment of the present disclosure. Referring to FIG. 4, a crash
pad 300 may further include a second adhesive layer 52 formed
between the cushion layer 20 and the core layer 10. When the second
adhesive layer 52 is included, the adhesion between the cushion
layer 20 and the core layer 10 may be improved.
[0108] The second adhesive layer 52 may include polyurethane. For
example, the second adhesive layer 52 may include organic
solvent-type polyurethane or water-dispersible polyurethane. In one
embodiment, the second adhesive layer may be formed using a second
adhesive composition. For example, the second adhesive composition
may include a polyol compound, an isocyanate-based curing agent,
and a solvent. The polyol compound, the isocyanate-based curing
agent and the solvent may be the same as those of the first
adhesive composition.
[0109] In one embodiment, the thickness of the second adhesive
layer may be 30 to 300 .mu.m. Within this thickness range, the
second adhesive layer may have excellent adhesion, and at the same
time, the airbag can be easily deployed through the skin layer in
the event of an external shock.
[0110] Core Layer
[0111] The core layer 10 forms the front of the driver's seat and
the passenger's seat and functions to protect the driver and the
passenger from an external shock when a crash or rollover accident
occurs. In addition, the core layer 10 may have an insertion hole
through which an airbag module is mounted, a mounting portion to
which an air conditioner is mounted, etc.
[0112] In one embodiment, the core layer may include a matrix resin
and an inorganic filler. For example, the matrix resin may include
one or more of a polyolefin-based resin, a polycarbonate-based
resin, and a styrene-based resin. The styrene-based resin may
include an acrylonitrile-butadiene-styrene (ABS) resin. In one
embodiment, the matrix resin may include one or more of a
polypropylene resin and a PC/ABS resin.
[0113] In one embodiment, the inorganic filler may include one or
more of talc, whisker, glass fiber, carbon fiber, basalt fiber, and
polymer fiber.
[0114] In one embodiment, the thickness of the core layer may be 1
to 6 mm. When the core layer is formed to have this thickness, it
may have excellent impact resistance, and the airbag deployment
performance in the event of an external shock may be excellent. For
example, the core layer may have a thickness of 3 to 4 mm. For
example, the thickness of the core layer may be 1, 2, 3, 4, 5 or 6
mm.
[0115] In one embodiment, the core layer may include an airbag door
portion through which the airbag is deployed. The airbag door
portion may have a tear line for airbag deployment formed therein,
and the tear line may have any one shape selected from among an "X"
shape, a modified "X" shape, a "-" shape, an "H" shape, and a "U"
shape. When the tear line is formed in this shape, the airbag can
be easily deployed in the event of an external shock.
[0116] Primer Layer
[0117] In one embodiment, the crash pad may further include a
primer layer (not shown) formed between the second adhesive layer
and the core layer. When the primer layer is formed, the adhesion
between the second adhesive layer and the core layer may be
excellent.
[0118] In one embodiment, the thickness of the primer layer may be
5 to 500 .mu.m. When the primer layer is formed to have this
thickness, the adhesion between the second adhesive layer and the
core layer may be excellent.
[0119] Method for Manufacturing Automotive Crash Pad
[0120] Another aspect of the present disclosure is directed to a
method for manufacturing an automotive crash pad. FIG. 5
illustrates a method for manufacturing an automotive crash pad
according to one embodiment of the present disclosure. Referring to
FIG. 5, the method for manufacturing an automotive crash pad
includes steps of: (S10) preparing an intermediate; and (S20)
laminating the intermediate, a fiber-based layer and a skin layer
together.
[0121] More specifically, the method for manufacturing an
automotive crash pad includes steps of: (S10) preparing an
intermediate by laminating a cushion layer and a core layer
together; and (S20) laminating a fiber-based layer and a skin layer
onto the intermediate, wherein a laminate of the skin layer and the
fiber-based layer has a tensile strength in transverse direction
(TD) of 5 to 50 kgf/3 cm and an elongation at break in transverse
direction (TD) of 40 to 220%.
[0122] Hereinafter, each step of the method for manufacturing an
automotive crash pad will be described in detail.
[0123] (S10) Step of Preparing Intermediate
[0124] This step is a step of preparing an intermediate by
laminating a cushion layer and a core layer together. The cushion
layer and the core layer that are used here may be the same as
those described above.
[0125] In one embodiment, the cushion layer may have a thickness of
1 to 10 mm. When the cushion layer is formed to have this
thickness, it may have excellent physical properties such as heat
resistance, impact resistance and light stability, and the airbag
deployment performance in the event of an external shock may be
excellent. For another example, the thickness may be 1 to 5 mm.
[0126] The cushion layer includes slab foam. In one embodiment, the
slab foam may be formed by foaming a first composition including a
polyol, an isocyanate-based curing agent and a foaming agent.
[0127] In one embodiment, the core layer may have a thickness of 1
to 6 mm. When the core layer is formed to have this thickness, it
may have excellent impact resistance, and at the same time, the
airbag deployment performance in the event of an external shock may
be excellent. For example, the thickness may be 3 to 4 mm.
[0128] In one embodiment, the cushion layer and the core layer may
be laminated together by forming a second adhesive layer between
the cushion layer and the core layer. For example, the cushion
layer and the core layer may be laminated together by applying a
second adhesive composition to one or more of the lower surface of
the cushion layer and the upper surface of the core layer and
curing the applied composition to form the second adhesive layer.
The second adhesive composition that is used here may be the same
as that described above.
[0129] In one embodiment, a primer layer (not shown) formed between
the second adhesive layer and the core layer may be further
included. When the primer layer is formed, the adhesion between the
second adhesive layer and the core layer may be excellent.
[0130] In one embodiment, the cushion layer and the core layer may
be laminated together by applying a primer to the surface of the
core layer, drying the applied primer to form a primer layer,
applying the second adhesive composition to each of the surface of
the primer layer and the surface of the cushion layer to be
laminated, and heating the applied composition. When the primer
layer is formed, the adhesion between the second adhesive layer and
the core layer may be excellent.
[0131] In one embodiment, the primer layer may have a thickness of
5 to 500 .mu.m. When the primer layer is formed to have this
thickness, the adhesion between the second adhesive layer and the
core layer may be excellent.
[0132] (S20) Step of Laminating Intermediate, Fiber-Based Layer and
Skin Layer Together
[0133] This step is a step of laminating a fiber-based layer and a
skin layer onto the intermediate. The fiber-based layer and the
skin layer that are used here may be the same as those described
above.
[0134] The skin layer may be formed using a skin layer composition
including 65 to 75 wt % of a polyol compound, 15 to 25 wt % of an
isocyanate-based curing agent, and 10 to 15 wt % of a chain
extender.
[0135] In one embodiment, a laminate of the skin layer and the
fiber-based layer have a tensile strength in transverse direction
(TD) of 5 to 50 kgf/3 cm and an elongation at break in transverse
direction (TD) of 40 to 220%. For example, a laminate of the skin
layer having a thickness of 0.1 to 0.7 mm and the fiber-based layer
having a thickness of 0.01 to 1 mm may have a tensile strength in
transverse direction (TD) of 5 to 50 kgf/3 cm and an elongation at
break in transverse direction (TD) of 40 to 220%, as measured at a
test speed of 200 mm/min using an Instron UTM instrument according
to Hyundai Motors Specification MS300-31.
[0136] If the laminate of the skin layer and the fiber-based layer
has the tensile strength in transverse direction (TD) of less than
5 kgf/3 cm, the laminate may be easily damaged by an external shock
because the strength thereof is excessively low, and if the
laminate has a tensile strength in transverse direction (TD) of
greater than 50 kgf/3 cm, the airbag cannot be deployed unless the
skin layer is subjected to the skiving or scoring process.
[0137] If the laminate of the skin layer and the fiber-based layer
has the elongation at break in transvers direction (TD) of less
than 40%, the airbag may be difficult to quickly deploy through the
skin layer in the event of an external shock, and if the laminate
has the elongation at break in transverse direction (TD) of greater
than 220%, the deployment shape of the airbag may be poor.
[0138] In one embodiment, the skin layer may have a thickness of
0.1 to 0.7 mm. Within this thickness range, the airbag can be
easily deployed through the skin layer in the event of an external
shock, even when the skin layer is not subjected to a skin
layer-weakening process such as scoring or skiving, and the skin
layer may have excellent mechanical properties.
[0139] In one embodiment, the skin layer may be formed by preparing
two or more skin layer materials and then sewing the materials
through single-needle stitching or double-needle stitching.
[0140] In one embodiment, the fiber-based layer may have a
thickness of 0.3 to 0.7 mm. Within this thickness range, the crash
pad may have excellent tactile sensation and cushion feeling, the
airbag can be easily deployed through the skin layer in the event
of an external shock, and the crash pad may have excellent physical
properties.
[0141] In one embodiment, the fiber-based layer and the skin layer
may be sequentially laminated onto one surface of the cushion layer
of the intermediate.
[0142] In one embodiment, in the step of laminating the fiber-based
layer and the skin layer onto the intermediate, the laminating may
be achieved by forming a first adhesive layer between the
fiber-based layer and the cushion layer. For example, the
laminating may be achieved by applying a first adhesive composition
to one or more of the lower surface of the fiber-based layer and
the upper surface of the cushion layer and curing the applied
composition to form the first adhesive layer. The first adhesive
composition that is used here may be the same as that described
above.
[0143] In one embodiment, the first adhesive layer may have a
thickness of 30 to 300 .mu.m. Within this thickness range, the
first adhesive layer may have excellent adhesion, and at the same
time, the airbag can be easily deployed through the skin layer in
the event of an external shock.
[0144] In one embodiment, a surface treatment layer may be further
formed on the upper surface of the skin layer. The surface
treatment layer may include a polyurethane resin. For another
example, the surface treatment layer may be formed by applying a
water-dispersible polyurethane resin composition to the upper
surface of the skin layer and curing the applied composition. The
surface treatment layer that is used here may be the same as that
described above.
[0145] In one embodiment, the surface treatment layer may have a
thickness of 1 to 200 .mu.m. Within this thickness range, the crash
pad may have excellent appearance, light stability and antifouling
properties.
[0146] (S30) Covering Step
[0147] In one embodiment, the method may further include a step of
covering the fiber-based layer, the cushion layer and the core
layer with the skin layer, after the step of laminating the
fiber-based layer and the skin layer onto the intermediate.
[0148] In the present disclosure, the covering means a process of
covering the fiber-based layer, the cushion layer and the core
layer with the skin layer.
[0149] In one embodiment, after the intermediate, the fiber-based
layer and the skin layer are laminated together and then the
laminated intermediate, fiber-based layer and skin layer are
pressed using a compression mold or the like, the fiber-based layer
and the intermediate may be covered with the skin layer.
[0150] In one embodiment, the skin layer may not be subjected to a
skiving or scoring process. The crash pad of the present disclosure
allows the airbag to be easily deployed in the event of an external
shock even when the skin layer-weakening process (skiving or
scoring process) is not performed. Thus, under the above-described
conditions, the skin layer-weakening process may be eliminated, and
thus the number of processes can be reduced and excellent economic
efficiency can be obtained.
[0151] In another embodiment of the present disclosure, the method
for manufacturing a crash pad may include steps of: (S11) preparing
a laminate; (S21) laminating the laminate and a core layer
together; and (S31) covering.
[0152] (S11) Step of Preparing Laminate
[0153] This step is a step of preparing a laminate by laminating a
skin layer, a fiber-based layer and a cushion layer together. The
skin layer, fiber-based layer and cushion layer that are used here
may be the same as those described above.
[0154] In one embodiment, the laminate may be prepared by
sequentially laminating the fiber-based layer and the cushion layer
on the lower surface of the skin layer. In one embodiment, in the
step of preparing the laminate, the laminating may be achieved by
forming a first adhesive layer between the fiber-based layer and
the cushion layer. For example, the laminating may be achieved by
applying a first adhesive composition to one or more of the lower
surface of the fiber-based layer and the upper surface of the
cushion layer and curing the applied composition to form the first
adhesive layer. The first adhesive composition that is used here
may be the same as that described above.
[0155] In one embodiment, the first adhesive layer may have a
thickness of 30 to 300 .mu.m. Within this thickness range, the
first adhesive layer may have excellent adhesion, and at the same
time, the airbag can be easily deployed through the skin layer in
the event of an external shock.
[0156] In one embodiment, a surface treatment layer may be further
formed on the upper surface of the skin layer. The surface
treatment layer may include a polyurethane resin. For another
example, the surface treatment layer may be formed by applying a
water-dispersible polyurethane resin composition to the upper
surface of the skin layer and curing the applied composition. The
surface treatment layer that is used here may be the same as that
described above.
[0157] In one embodiment, the surface treatment layer may have a
thickness of 1 to 200 .mu.m. Within this thickness range, the crash
pad may have excellent appearance, light stability and antifouling
properties.
[0158] (S21) Step of Laminating Laminate and Core Layer
Together
[0159] This step is a step of laminating the laminate and a core
layer together. The core layer that is used here may be the same as
that described above.
[0160] In one embodiment, the thickness of the core layer may be 1
to 6 mm. When the core layer is formed to have this thickness, it
may have excellent impact resistance, and at the same time, the
airbag deployment performance in the event of an external shock may
be excellent. For example, the thickness thereof may be 3 to 4
mm.
[0161] In one embodiment, in the step of laminating the laminate
and the core layer together, the laminating may be achieved by
forming a second adhesive layer between the cushion layer of the
stack and the core layer. For example, the laminating may be
achieved by applying a second adhesive composition to one or more
of the lower surface of the cushion layer of the laminate and the
upper surface of the core layer and curing the applied composition
to form the second adhesive layer. The second adhesive composition
that is used here may be the same as that described above.
[0162] In one embodiment, the thickness of the second adhesive
layer may be 30 to 300 .mu.m. Within this thickness range, the
second adhesive layer may have excellent adhesion, and at the same
time, the airbag can be easily deployed through the skin layer in
the event of an external shock.
[0163] In one embodiment, the laminate and the core layer may be
laminated together by applying a primer to the surface of the core
layer, drying the applied primer to form a primer layer, applying
the second adhesive composition to each of the surface of the
primer layer and the surface of the cushion layer to be laminated,
and heating the applied composition. When the primer layer is
formed, the adhesion between the core layer and the second adhesive
layer may be excellent.
[0164] In one embodiment, the primer layer may have a thickness of
5 to 500 .mu.m. When the primer layer is formed to have this
thickness, the adhesion between the second adhesive layer and the
core layer may be excellent.
[0165] (S31) Covering Step
[0166] In one embodiment, the method may further include a step of
covering the fiber-based layer, the cushion layer and the core
layer with the skin layer, after the step of laminating the
laminate and the core layer together.
[0167] In the present disclosure, the covering means a process of
bringing the lower surface of the cushion layer of the laminate
into contact with the upper surface of the core layer, and then
covering the cushion layer and the core layer with the skin layer
of the laminate.
[0168] In one embodiment, after the laminate and the core layer are
laminated together and the laminated laminate and core layer are
pressed using a compression mold or the like, the fiber-based
layer, the cushion layer and the core layer may be covered with the
skin layer.
[0169] In one embodiment, the skin layer may not be subjected to a
skiving or scoring process. The crash pad of the present disclosure
allows the airbag to be easily deployed even when the skin
layer-weakening process (skiving or scoring process) is not
performed. Thus, under the above-described conditions, the skin
layer-weakening process may be eliminated, and thus the number of
processes can be reduced and excellent economic efficiency can be
obtained.
[0170] Hereinafter, the configuration and effects of the present
disclosure will be described in more detail with reference to
preferred examples. However, these examples are presented as
preferred examples of the present disclosure and may not be
construed as limiting the scope of the present disclosure in any
sense. The contents that are not described herein can be
sufficiently and technically envisioned by those skilled in the
art, and thus the description thereof will be omitted herein.
EXAMPLES AND COMPARATIVE EXAMPLES
Example 1
[0171] (1) Preparation of intermediate: A 1 to 6-mm-thick core
layer including polypropylene was prepared. In addition, a cushion
layer including slab foam was prepared, which was formed by foaming
a first composition including 40 to 75 wt % of a polyol compound,
15 to 45 wt % of an isocyanate-based curing agent and 1 to 15 wt %
of a foaming agent.
[0172] A primer was applied to the upper surface of the core layer
and dried to form a primer layer (thickness: 5 to 10 .mu.m).
[0173] A second adhesive composition including polyurethane was
applied to each of the lower surface of the cushion layer and the
upper surface of the primer layer to form a second adhesive layer
(thickness: 1 to 15 .mu.m) including water-dispersible
polyurethane, and then the lower surface of the cushion layer and
the upper surface of the primer layer were heat-cured and laminated
together, thereby preparing an intermediate.
[0174] (2) Lamination of fiber-based layer and skin layer onto
intermediate: A skin layer material was formed according to a
conventional method using a skin layer composition including 65 to
75 wt % of a polyol compound, 15 to 25 wt % of an isocyanate-based
curing agent and 10 to 15. In the following description, the
detailed description of related publicly-known technology or
configuration will be omitted when it may unnecessarily obscure the
subject matter of the present disclosure.
[0175] In addition, the terms used in the following description are
terms defined considering the functions in the present disclosure,
and may be changed in accordance with the option of a user or
operator or a usual practice. Accordingly, the definition of the
terms should be made based on the contents throughout the present
specification.
[0176] In the present specification, the terms "upper portion" and
"lower portion" are defined based on the drawings, and depending on
the point of view, "upper portion" may be changed to "lower
portion" and "lower portion" may be changed to "upper portion". In
addition, in the present disclosure, when one element is referred
to as being "on" another element, it refers to not only a case
where the element is formed directly located "on" the other element
but also a case where an additional element exists between these
elements.
[0177] Automotive Crash Pad
[0178] One aspect of the present disclosure is directed to an
automotive crash pad. FIG. 3 illustrates a crash pad according to
one embodiment of the present disclosure. Referring to FIG. 3, an
automotive crash pad 200 includes: a skin layer 40 forming the
outer surface of the crash pad including an airbag module; a
fiber-based layer 30 formed on the lower surface of the skin layer
40; a cushion layer 20 formed on the lower surface of the
fiber-based layer 30 and including slab foam; and a core layer 10
formed on the lower surface of the cushion layer 20.
[0179] A laminate of the skin layer and the fiber-based layer has a
tensile strength in transverse direction (TD) of 5 to 50 kgf/3 cm
and an elongation at break in transverse direction (TD) of 40 to
220%.
[0180] Skin Layer
[0181] The skin layer 40 forms the appearance of the crash pad 200,
and may give a user sensitivity, such as tactile sensation and
cushion feeling.
[0182] In one embodiment, the skin layer 40 may have a thickness of
0.1 to 0.7 mm. Within this thickness range, the airbag may be
easily deployed through the skin layer in the event of an external
shock, even when the skin layer is not subjected to a skin
layer-weakening process such as scoring or skiving, and the skin
layer may have excellent mechanical properties. For example, the
skin layer may have a thickness of 0.1 to 0.4 mm. For example, the
skin layer 40 may have a thickness of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6
or 0.7 mm.
[0183] In one embodiment, a laminate of the skin layer and the
fiber-based layer may have a tensile strength in transverse
direction (TD) of 5 to 50 kgf/3 cm and an elongation at break in
transverse direction (TD) of 40 to 220%. For example, a laminate of
the skin layer having a thickness of 0.1 to 0.7 mm and the
fiber-based layer having a thickness of 0.01 to 1 mm may have a
tensile strength in transverse direction (TD) of 5 to 50 kgf/3 cm
and an elongation at break in transverse direction (TD) of 40 to
220%, as measured at a test speed of 200 mm/min using an Instron
UTM instrument according to Hyundai Motors Specification
MS300-31.
[0184] If the laminate of the skin layer and the fiber-based layer
has the tensile strength in transverse direction (TD) of less than
5 kgf/3 cm, the laminate may be easily damaged by an external shock
because the strength thereof is excessively low, and if the
laminate has a tensile strength in transverse direction of greater
than 50 kgf/3 cm, the airbag cannot be deployed unless the skin
layer is subjected to the skiving or scoring process. For example,
the laminate of the skin layer and the fiber-based layer may have
the tensile strength in transverse direction (TD) of 5, 6, 7, 8, 9,
10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26,
27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43,
44, 45, 46, 47, 48, 49 or 50 kgf/3 cm.
[0185] If the laminate of the skin layer and the fiber-based layer
has the elongation at break in transvers direction (TD) of less
than 40%, the airbag may be difficult to quickly deploy through the
skin layer in the event of an external shock, and if the laminate
has the elongation at break in transverse direction (TD) of greater
than 220%, the deployment shape of the airbag may be poor. For
example, the laminate of the skin layer and the fiber-based layer
may have the elongation at break in transvers direction (TD) of 40,
50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180,
190, 200, 210 or 220%.
[0186] The skin layer may have a tearing strength of 2 to 8 kgf/cm.
Under this condition, the skin layer may have excellent mechanical
properties, and at the same time, the airbag can easily be deployed
even when the skin layer is not subjected to the skiving or scoring
process. For example, the skin layer may have a tearing strength of
2, 3, 4, 5, 6, 7 or 8 kgf/cm.
[0187] In one embodiment, the skin layer may be formed to include
one or more of thermoplastic polyurethane, thermoplastic
polyolefin, polyvinyl chloride and thermosetting polyurethane. For
example, the skin layer may include thermosetting polyurethane.
[0188] In one embodiment, the skin layer may be formed using a skin
layer composition. The skin layer composition may include 65 to 75
wt % of a polyol compound, 15 to 25 wt % of an isocyanate-based
curing agent, and 10 to 15 wt % of a chain extender. Under the
above conditions, it is possible to easily achieve the mechanical
properties of the skin layer targeted by the present
disclosure.
[0189] In one embodiment, the polyol compound may include one or
more of diol, triol, and polymer polyol.
[0190] In one embodiment, the diol may include one or more of
ethylene glycol, diethylene glycol, butanediol and hexanediol.
[0191] In one embodiment, the triol may include one or more of
glycerin, trimethylolpropane, and 1,2,3-hexanetriol.
[0192] In one embodiment, the polymer polyol may include one or
more of polyolefin polyol, polyester polyol, polycaprolactone
polyol, polyether polyol, and polycarbonate polyol.
[0193] In one embodiment, the polyol compound may be included in an
amount of 65 to 75 wt % based on the total weight of the skin layer
composition. Under this condition, the mechanical properties of the
skin layer targeted by the present disclosure may be easily
achieved. For example, the polyol compound may be included in an
amount of 65, 66, 67, 68, 69, 70, 71, 72, 73, 74 or 75 wt %, based
on the total weight of the skin layer composition.
[0194] The isocyanate-based curing agent may react with the polyol
compound to form the skin layer. In one embodiment, the
isocyanate-based curing agent may include one or more of
4,4'-dicyclohexylmethane diisocyanate, 4,4-dimethylphenylmethane
diisocyanate, bis-4-(isocyanate cyclohexyl)methane, hexamethylene
diisocyanate, xylene diisocyanate, p-phenylene diisocyanate,
tolidine diisocyanate, tetramethylene diisocyanate, dimethyl
diisocyanate, trimethyl hexamethylene diisocyanate, phenylene
diisocyanate, and dimethyl diphenyl diisocyanate.
[0195] In one embodiment, the isocyanate-based curing agent may be
included in an amount of 15 to 25 wt % based on the total weight of
the skin layer composition. Under this condition, the mechanical
properties of the skin layer targeted by the present disclosure may
be easily achieved. For example, the isocyanate-based curing agent
may be included in an amount of 15, 16, 17, 18, 19, 20, 21, 22, 23,
24 or 25 wt %, based on the total weight of the skin layer
composition.
[0196] The chain extender may be included for the purpose of
chain-extending or crosslinking the polyurethane formed in the skin
layer to increase the molecular weight of the polyurethane and
improve mechanical properties, heat resistance and chemical
resistance.
[0197] In one embodiment, the chain extender may include one or
more of diol, triol, and amine compounds. For example, the chain
extender may include one or more of ethylene glycol, propylene
glycol, 1,4-butanediol, glycerin, diethanolamine (DEOA), and
triethanolamine (TEOA).
[0198] In one embodiment, the chain extender may be included in an
amount of 10 to 15 wt % based on the total weight of the skin layer
composition. Under this condition, the mechanical properties of the
skin layer targeted by the present disclosure may be easily
achieved. For example, the chain extender may be included in an
amount of 10, 11, 12, 13, 14 or 15 wt %, based on the total weight
of the skin layer composition.
[0199] In one embodiment, the skin layer may not be subjected to a
skiving or scoring process. The crash pad of the present disclosure
allows the airbag to easily be deployed in the event of an external
shock even when the skin layer-weakening process (skiving or
scoring process) is not performed. Thus, under the above-described
conditions, the skin layer-weakening process may be eliminated, and
thus the number of processes can be reduced and excellent economic
efficiency can be obtained.
[0200] Fiber-Based Layer
[0201] The fiber-based layer 30 is included for the purpose of
improving the tactile sensation, cushion feeling and appearance of
the crash pad of the present disclosure. In one embodiment, the
fiber-based layer 30 may include one or more of polyethylene
terephthalate (PET) and polyamide (PA). When the fiber-based layer
is included, the tactile sensation and appearance of the crash pad
of the present disclosure may be excellent.
[0202] In one embodiment, the fiber-based layer 30 may be in the
form of a knitted or nonwoven fabric. For example, it may be in the
form of a knitted fabric. When the fiber-based layer 30 is in this
form, the crash pad may have excellent tactile sensation and
cushion feeling, and the airbag can be easily deployed through the
skin layer in the event of an external shock.
[0203] For example, the fiber-based layer may be in the form of a
knitted fabric including PET fiber, and may have a weight of 150 to
200 g/m2 and a fineness of 20 denier to 500 denier. Under these
conditions, the crash pad may have excellent lightweight
properties, tactile sensation and cushion feeling, and the airbag
can be easily deployed in the event of an external shock.
[0204] In one embodiment, the fiber-based layer 30 may have a
density of 0.22 to 0.27 g/cm3 and a thickness of 0.01 to 1 mm.
within the density and thickness ranges, the crash pad may have
excellent tactile sensation and cushion feeling, the airbag can be
easily deployed through the skin layer in the event of an external
shock, and the fiber-based layer may have excellent mechanical
properties. For example, the fiber-based layer may have a density
of 0.22, 0.23, 0.24, 0.25, 0.26 or 0.27 g/cm3. For example, the
fiber-based layer 30 may have a thickness of 0.3 to 0.7 mm.
[0205] Surface Treatment Layer
[0206] In one embodiment, the crash pad may further include a
surface treatment layer formed on the skin layer. The surface
treatment layer may be included for the purpose of improving
functions such as light stability and antifouling properties while
controlling the gloss of the skin layer and expressing color.
[0207] In one embodiment, the surface treatment layer may include a
polyurethane resin. For another example, the surface treatment
layer may be formed by applying and curing a water-dispersible
polyurethane resin composition. In one embodiment, the
water-dispersible polyurethane resin may include a polyol compound,
a chain extender, an isocyanate-based curing agent, and water, but
is not limited thereto.
[0208] In one embodiment, the thickness of the surface treatment
layer may be 1 to 200 .mu.m. Within this thickness range, the crash
pad may have excellent appearance, light stability and antifouling
properties.
[0209] First Adhesive Layer
[0210] Referring to FIG. 3, the crash pad 200 may further include a
first adhesive layer 50 between the fiber-based layer 30 and the
cushion layer 20. When the first adhesive layer 50 is included,
adhesion between the fiber-based layer and the cushion layer may be
improved.
[0211] The first adhesive layer 50 may include polyurethane. For
example, it may include organic solvent-type polyurethane or
water-dispersible polyurethane. In one embodiment, the first
adhesive layer may be formed using a first adhesive composition.
For example, the first adhesive composition may include a polyol
compound, an isocyanate-based curing agent, and a solvent.
[0212] In one embodiment, the polyol compound may include one or
more of diol, triol and polymer polyol.
[0213] In one embodiment, the diol may include one or more of
ethylene glycol, diethylene glycol, butanediol, and hexanediol.
[0214] In one embodiment, the triol may include one or more of
glycerin, trimethylolpropane, and 1,2,3-hexanetriol.
[0215] In one embodiment, the polymer polyol may include one or
more of polyolefin polyol, polyester polyol, polycaprolactone
polyol, polyether polyol, and polycarbonate polyol.
[0216] The isocyanate-based curing agent may react with the polyol
compound to form the first adhesive layer. In one embodiment, the
isocyanate-based curing agent may include one or more of
4,4'-dicyclohexylmethane diisocyanate, 4,4-dimethylphenylmethane
diisocyanate, bis-4-(isocyanate cyclohexyl)methane, hexamethylene
diisocyanate, xylene diisocyanate, p-phenylene diisocyanate,
tolidine diisocyanate, tetramethylene diisocyanate, dimethyl
diisocyanate, trimethyl hexamethylene diisocyanate, phenylene
diisocyanate, and dimethyl diphenyl diisocyanate.
[0217] In one embodiment, the solvent may include one or more of
water, an alcohol having 1 to 10 carbon atoms, toluene, acetone,
methyl ethyl ketone, dimethylformamide, and cyclohexane.
[0218] In one embodiment, the adhesive strength between a laminate
of the skin layer and the fiber-based layer and the cushion layer
may be 0.3 kgf/cm or more, as measured according to the ISO 813
standard. The adhesive strength may be a result obtained by
measuring the adhesive strength between the skin layer/fiber-based
layer laminate and the cushion layer according to Hyundai-Kia
Motors MS Specification 256-29 (ISO 813 standard; 90.degree.
peeling method; peeling speed: 25 mm/min). If the adhesive strength
is less than 0.3 kgf/cm, the adhesion between the laminate and the
first adhesive layer (cushion layer) may be poor, and the tear
shape of the airbag may be poor. For example, the adhesive strength
may be 0.3 to 1.2 kgf/cm. For example, it may be 0.3, 0.4, 0.5,
0.6, 0.7, 0.8, 0.9, 1, 1.1 or 1.2 kgf/cm.
[0219] In one embodiment, the laminate of the skin layer and the
fiber-based layer may have an adhesive strength of 0.3 kgf/cm or
more to the first adhesive layer, as measured according to the ISO
813 standard. The adhesive strength may be a result obtained by
measuring the adhesive strength between the skin layer/fiber-based
layer laminate and the first adhesive layer according to
Hyundai-Kia Motors MS Specification 256-29 (ISO 813 standard;
90.degree. peeling method; peeling speed: 25 mm/min). If the
adhesive strength is less than 0.3 kgf/cm, the adhesion between the
laminate and the first adhesive layer (cushion layer) may be poor,
and the tear shape of the airbag may be poor. For example, the
adhesive strength may be 0.3 to 1.2 kgf/cm. For example, it may be
0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1 or 1.2 kgf/cm.
[0220] In one embodiment, the thickness of the first adhesive layer
50 may be 30 to 300 .mu.m. Within this thickness range, the first
adhesive layer may have excellent adhesion, and at the same time,
the airbag can be easily deployed through the skin layer in the
event of an external shock.
[0221] Cushion Layer
[0222] The cushion layer functions to secure the physical
properties of the crash pad, such as heat resistance, impact
resistance and light stability, and to impart tactile sensation
such as cushion feeling to the driver and the passenger.
[0223] In one embodiment, the cushion layer includes slab foam.
When the slab foam is included, the cushion layer may have
excellent airbag deployment performance and cushion feeling
compared to a conventional filament layer, and have excellent
economic efficiency because of being cheaper than the conventional
filament layer, and the airbag can be easily deployed in the event
of an external shock while the airbag module is prevented from
damage.
[0224] In one embodiment, the slab foam may be formed by foaming a
first composition including a polyol compound, an isocyanate-based
curing agent and a foaming agent.
[0225] In one embodiment, the polyol compound may include one or
more of diol, triol, and polymer polyol.
[0226] In one embodiment, the diol may include one or more of
ethylene glycol, diethylene glycol, butanediol, and hexanediol.
[0227] In one embodiment, the triol may include one or more of
glycerin, trimethylolpropane, and 1,2,3-hexanetriol.
[0228] In one embodiment, the polymer polyol may include one or
more of polyolefin polyol, polyester polyol, polycaprolactone
polyol, polyether polyol, and polycarbonate polyol.
[0229] In one embodiment, the polyol compound may be included in an
amount of 40 to 75 wt % based on the total weight of the first
composition. When the polyol compound is included in an amount
within the above range, the slab foam may have excellent mechanical
strength. For example, the polyol compound may be included in an
amount of 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53,
54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70,
71, 72, 73, 74 or 75 wt %, based on the total weight of the first
composition.
[0230] The isocyanate-based curing agent may react with the polyol
compound to form the slab foam. In one embodiment, the
isocyanate-based curing agent may include one or more of
4,4'-dicyclohexylmethane diisocyanate, 4,4-dimethylphenylmethane
diisocyanate, bis-4-(isocyanate cyclohexyl)methane, hexamethylene
diisocyanate, xylene diisocyanate, p-phenylene diisocyanate,
tolidine diisocyanate, tetramethylene diisocyanate, dimethyl
diisocyanate, trimethyl hexamethylene diisocyanate, phenylene
diisocyanate, and dimethyl diphenyl diisocyanate.
[0231] In one embodiment, the isocyanate-based curing agent may be
included in an amount of 15 to 45 wt % based on the total weight of
the first composition. When the isocyanate-based curing agent is
included in an amount within this range, the slab foam may have
excellent mechanical strength. For example, the isocyanate-based
curing agent may be included in an amount of 15, 16, 17, 18, 19,
20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36,
37, 38, 39, 40, 41, 42, 43, 44 or 45 wt %, based on the total
weight of the first composition.
[0232] The foaming agent may include one or more of water, butane,
n-pentane, c-pentane, hexane, heptane, chlorofluorocarbon (CFC 11),
hydrogen chlorofluorocarbons (H-CFCs), hydrogen fluorocarbons
(H-FCs), trichlorofluoromethane (Freon 11), chlorodifluoromethane
(R-22), 1,1-dichloro-1-fluoroethane (HCFC-141b), and
1,1,1,3,3-pentafluoropropane (HFC-245fa).
[0233] In one embodiment, the foaming agent may be included in an
amount of 1 to 15 wt % based on the total weight of the first
composition. When the foaming agent is included in an amount within
this range, the slab foam may have excellent mechanical strength.
For example, the foaming agent may be included in an amount of 1,
2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15 wt %, based on the
total weight of the first composition.
[0234] In one embodiment, the cushion layer may have a density of
0.05 to 5 g/cm3 and a porosity of 5 to 80%. Under these conditions,
the crash pad may have excellent lightweight and mechanical
strength properties.
[0235] In one embodiment, the cushion layer may have a tensile
strength of 3 to 20 kgf/cm2, an elongation of 50 to 200% and a
tearing strength of 0.2 to 1.5 kgf/cm, as measured according to
Hyundai Motors Specification MS300-31. Under these tensile
strength, elongation and tearing strength conditions, the cushion
layer may have excellent physical properties, and at the same time,
the air bag can be easily deployed through the cushion layer in the
event of an external shock.
[0236] For example, the cushion layer may have a tensile strength
of 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or
20 kgf/cm2, as measured according to Hyundai Motors Specification
MS300-31, an elongation of 50, 60, 70, 80, 90, 100, 110, 120, 130,
140, 150, 160, 170, 180, 190 or 200%, as measured according to
Hyundai Motors Specification MS300-31, and a tearing strength of
0.2. 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4 or
1.5 kgf/cm, as measured according to Hyundai Motors Specification
MS300-31.
[0237] For example, the cushion layer may have a thickness of 1 to
10 mm. When the cushion layer is formed to have this thickness, the
cushion layer may have excellent physical properties, such as heat
resistance, impact resistance and light stability, and the airbag
deployment performance in the event of an external shock may be
excellent. For another example, the cushion layer may have a
thickness of 1 to 5 mm. For example, the cushion layer may have a
thickness of 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 mm.
[0238] Second Adhesive Layer
[0239] FIG. 4 illustrates a crash pad according to another
embodiment of the present disclosure. Referring to FIG. 4, a crash
pad 300 may further include a second adhesive layer 52 formed
between the cushion layer 20 and the core layer 10. When the second
adhesive layer 52 is included, the adhesion between the cushion
layer 20 and the core layer 10 may be improved.
[0240] The second adhesive layer 52 may include polyurethane. For
example, the second adhesive layer 52 may include organic
solvent-type polyurethane or water-dispersible polyurethane. In one
embodiment, the second adhesive layer may be formed using a second
adhesive composition. For example, the second adhesive composition
may include a polyol compound, an isocyanate-based curing agent,
and a solvent. The polyol compound, the isocyanate-based curing
agent and the solvent may be the same as those of the first
adhesive composition.
[0241] In one embodiment, the thickness of the second adhesive
layer may be 30 to 300 .mu.m. Within this thickness range, the
second adhesive layer may have excellent adhesion, and at the same
time, the airbag can be easily deployed through the skin layer in
the event of an external shock.
[0242] Core Layer
[0243] The core layer 10 forms the front of the driver's seat and
the passenger's seat and functions to protect the driver and the
passenger from an external shock when a crash or rollover accident
occurs. In addition, the core layer 10 may have an insertion hole
through which an airbag module is mounted, a mounting portion to
which an air conditioner is mounted, etc.
[0244] In one embodiment, the core layer may include a matrix resin
and an inorganic filler. For example, the matrix resin may include
one or more of a polyolefin-based resin, a polycarbonate-based
resin, and a styrene-based resin. The styrene-based resin may
include an acrylonitrile-butadiene-styrene (ABS) resin. In one
embodiment, the matrix resin may include one or more of a
polypropylene resin and a PC/ABS resin.
[0245] In one embodiment, the inorganic filler may include one or
more of talc, whisker, glass fiber, carbon fiber, basalt fiber, and
polymer fiber.
[0246] In one embodiment, the thickness of the core layer may be 1
to 6 mm. When the core layer is formed to have this thickness, it
may have excellent impact resistance, and the airbag deployment
performance in the event of an external shock may be excellent. For
example, the core layer may have a thickness of 3 to 4 mm. For
example, the thickness of the core layer may be 1, 2, 3, 4, 5 or 6
mm.
[0247] In one embodiment, the core layer may include an airbag door
portion through which the airbag is deployed. The airbag door
portion may have a tear line for airbag deployment formed therein,
and the tear line may have any one shape selected from among an "X"
shape, a modified "X" shape, a "-" shape, an "H" shape, and a "U"
shape. When the tear line is formed in this shape, the airbag can
be easily deployed in the event of an external shock.
[0248] Primer Layer
[0249] In one embodiment, the crash pad may further include a
primer layer (not shown) formed between the second adhesive layer
and the core layer. When the primer layer is formed, the adhesion
between the second adhesive layer and the core layer may be
excellent.
[0250] In one embodiment, the thickness of the primer layer may be
5 to 500 .mu.m. When the primer layer is formed to have this
thickness, the adhesion between the second adhesive layer and the
core layer may be excellent.
[0251] Method for Manufacturing Automotive Crash Pad
[0252] Another aspect of the present disclosure is directed to a
method for manufacturing an automotive crash pad. FIG. 5
illustrates a method for manufacturing an automotive crash pad
according to one embodiment of the present disclosure. Referring to
FIG. 5, the method for manufacturing an automotive crash pad
includes steps of: (S10) preparing an intermediate; and (S20)
laminating the intermediate, a fiber-based layer and a skin layer
together.
[0253] More specifically, the method for manufacturing an
automotive crash pad includes steps of: (S10) preparing an
intermediate by laminating a cushion layer and a core layer
together; and (S20) laminating a fiber-based layer and a skin layer
onto the intermediate, wherein a laminate of the skin layer and the
fiber-based layer has a tensile strength in transverse direction
(TD) of 5 to 50 kgf/3 cm and an elongation at break in transverse
direction (TD) of 40 to 220%.
[0254] Hereinafter, each step of the method for manufacturing an
automotive crash pad will be described in detail.
[0255] (S10) Step of Preparing Intermediate
[0256] This step is a step of preparing an intermediate by
laminating a cushion layer and a core layer together. The cushion
layer and the core layer that are used here may be the same as
those described above.
[0257] In one embodiment, the cushion layer may have a thickness of
1 to 10 mm. When the cushion layer is formed to have this
thickness, it may have excellent physical properties such as heat
resistance, impact resistance and light stability, and the airbag
deployment performance in the event of an external shock may be
excellent. For another example, the thickness may be 1 to 5 mm.
[0258] The cushion layer includes slab foam. In one embodiment, the
slab foam may be formed by foaming a first composition including a
polyol, an isocyanate-based curing agent and a foaming agent.
[0259] In one embodiment, the core layer may have a thickness of 1
to 6 mm. When the core layer is formed to have this thickness, it
may have excellent impact resistance, and at the same time, the
airbag deployment performance in the event of an external shock may
be excellent. For example, the thickness may be 3 to 4 mm.
[0260] In one embodiment, the cushion layer and the core layer may
be laminated together by forming a second adhesive layer between
the cushion layer and the core layer. For example, the cushion
layer and the core layer may be laminated together by applying a
second adhesive composition to one or more of the lower surface of
the cushion layer and the upper surface of the core layer and
curing the applied composition to form the second adhesive layer.
The second adhesive composition that is used here may be the same
as that described above.
[0261] In one embodiment, a primer layer (not shown) formed between
the second adhesive layer and the core layer may be further
included. When the primer layer is formed, the adhesion between the
second adhesive layer and the core layer may be excellent.
[0262] In one embodiment, the cushion layer and the core layer may
be laminated together by applying a primer to the surface of the
core layer, drying the applied primer to form a primer layer,
applying the second adhesive composition to each of the surface of
the primer layer and the surface of the cushion layer to be
laminated, and heating the applied composition. When the primer
layer is formed, the adhesion between the second adhesive layer and
the core layer may be excellent.
[0263] In one embodiment, the primer layer may have a thickness of
5 to 500 um. When the primer layer is formed to have this
thickness, the adhesion between the second adhesive layer and the
core layer may be excellent.
[0264] (S20) Step of Laminating Intermediate, Fiber-Based Layer and
Skin Layer Together
[0265] This step is a step of laminating a fiber-based layer and a
skin layer onto the intermediate. The fiber-based layer and the
skin layer that are used here may be the same as those described
above.
[0266] The skin layer may be formed using a skin layer composition
including 65 to 75 wt % of a polyol compound, 15 to 25 wt % of an
isocyanate-based curing agent, and 10 to 15 wt % of a chain
extender.
[0267] In one embodiment, a laminate of the skin layer and the
fiber-based layer have a tensile strength in transverse direction
(TD) of 5 to 50 kgf/3 cm and an elongation at break in transverse
direction (TD) of 40 to 220%. For example, a laminate of the skin
layer having a thickness of 0.1 to 0.7 mm and the fiber-based layer
having a thickness of 0.01 to 1 mm may have a tensile strength in
transverse direction (TD) of 5 to 50 kgf/3 cm and an elongation at
break in transverse direction (TD) of 40 to 220%, as measured at a
test speed of 200 mm/min using an Instron UTM instrument according
to Hyundai Motors Specification MS300-31.
[0268] If the laminate of the skin layer and the fiber-based layer
has the tensile strength in transverse direction (TD) of less than
5 kgf/3 cm, the laminate may be easily damaged by an external shock
because the strength thereof is excessively low, and if the
laminate has a tensile strength in transverse direction (TD) of
greater than 50 kgf/3 cm, the airbag cannot be deployed unless the
skin layer is subjected to the skiving or scoring process.
[0269] If the laminate of the skin layer and the fiber-based layer
has the elongation at break in transvers direction (TD) of less
than 40%, the airbag may be difficult to quickly deploy through the
skin layer in the event of an external shock, and if the laminate
has the elongation at break in transverse direction (TD) of greater
than 220%, the deployment shape of the airbag may be poor.
[0270] In one embodiment, the skin layer may have a thickness of
0.1 to 0.7 mm. Within this thickness range, the airbag can be
easily deployed through the skin layer in the event of an external
shock, even when the skin layer is not subjected to a skin
layer-weakening process such as scoring or skiving, and the skin
layer may have excellent mechanical properties.
[0271] In one embodiment, the skin layer may be formed by preparing
two or more skin layer materials and then sewing the materials
through single-needle stitching or double-needle stitching.
[0272] In one embodiment, the fiber-based layer may have a
thickness of 0.3 to 0.7 mm. Within this thickness range, the crash
pad may have excellent tactile sensation and cushion feeling, the
airbag can be easily deployed through the skin layer in the event
of an external shock, and the crash pad may have excellent physical
properties.
[0273] In one embodiment, the fiber-based layer and the skin layer
may be sequentially laminated onto one surface of the cushion layer
of the intermediate.
[0274] In one embodiment, in the step of laminating the fiber-based
layer and the skin layer onto the intermediate, the laminating may
be achieved by forming a first adhesive layer between the
fiber-based layer and the cushion layer. For example, the
laminating may be achieved by applying a first adhesive composition
to one or more of the lower surface of the fiber-based layer and
the upper surface of the cushion layer and curing the applied
composition to form the first adhesive layer. The first adhesive
composition that is used here may be the same as that described
above.
[0275] In one embodiment, the first adhesive layer may have a
thickness of 30 to 300 .mu.m. Within this thickness range, the
first adhesive layer may have excellent adhesion, and at the same
time, the airbag can be easily deployed through the skin layer in
the event of an external shock.
[0276] In one embodiment, a surface treatment layer may be further
formed on the upper surface of the skin layer. The surface
treatment layer may include a polyurethane resin. For another
example, the surface treatment layer may be formed by applying a
water-dispersible polyurethane resin composition to the upper
surface of the skin layer and curing the applied composition. The
surface treatment layer that is used here may be the same as that
described above.
[0277] In one embodiment, the surface treatment layer may have a
thickness of 1 to 200 .mu.m. Within this thickness range, the crash
pad may have excellent appearance, light stability and antifouling
properties.
[0278] (S30) Covering Step
[0279] In one embodiment, the method may further include a step of
covering the fiber-based layer, the cushion layer and the core
layer with the skin layer, after the step of laminating the
fiber-based layer and the skin layer onto the intermediate.
[0280] In the present disclosure, the covering means a process of
covering the fiber-based layer, the cushion layer and the core
layer with the skin layer.
[0281] In one embodiment, after the intermediate, the fiber-based
layer and the skin layer are laminated together and then the
laminated intermediate, fiber-based layer and skin layer are
pressed using a compression mold or the like, the fiber-based layer
and the intermediate may be covered with the skin layer.
[0282] In one embodiment, the skin layer may not be subjected to a
skiving or scoring process. The crash pad of the present disclosure
allows the airbag to be easily deployed in the event of an external
shock even when the skin layer-weakening process (skiving or
scoring process) is not performed. Thus, under the above-described
conditions, the skin layer-weakening process may be eliminated, and
thus the number of processes can be reduced and excellent economic
efficiency can be obtained.
[0283] In another embodiment of the present disclosure, the method
for manufacturing a crash pad may include steps of: (S11) preparing
a laminate; (S21) laminating the laminate and a core layer
together; and (S31) covering.
[0284] (S11) Step of Preparing Laminate
[0285] This step is a step of preparing a laminate by laminating a
skin layer, a fiber-based layer and a cushion layer together. The
skin layer, fiber-based layer and cushion layer that are used here
may be the same as those described above.
[0286] In one embodiment, the laminate may be prepared by
sequentially laminating the fiber-based layer and the cushion layer
on the lower surface of the skin layer. In one embodiment, in the
step of preparing the laminate, the laminating may be achieved by
forming a first adhesive layer between the fiber-based layer and
the cushion layer. For example, the laminating may be achieved by
applying a first adhesive composition to one or more of the lower
surface of the fiber-based layer and the upper surface of the
cushion layer and curing the applied composition to form the first
adhesive layer. The first adhesive composition that is used here
may be the same as that described above.
[0287] In one embodiment, the first adhesive layer may have a
thickness of 30 to 300 .mu.m. Within this thickness range, the
first adhesive layer may have excellent adhesion, and at the same
time, the airbag can be easily deployed through the skin layer in
the event of an external shock.
[0288] In one embodiment, a surface treatment layer may be further
formed on the upper surface of the skin layer. The surface
treatment layer may include a polyurethane resin. For another
example, the surface treatment layer may be formed by applying a
water-dispersible polyurethane resin composition to the upper
surface of the skin layer and curing the applied composition. The
surface treatment layer that is used here may be the same as that
described above.
[0289] In one embodiment, the surface treatment layer may have a
thickness of 1 to 200 .mu.m. Within this thickness range, the crash
pad may have excellent appearance, light stability and antifouling
properties.
[0290] (S21) Step of Laminating Laminate and Core Layer
Together
[0291] This step is a step of laminating the laminate and a core
layer together. The core layer that is used here may be the same as
that described above.
[0292] In one embodiment, the thickness of the core layer may be 1
to 6 mm. When the core layer is formed to have this thickness, it
may have excellent impact resistance, and at the same time, the
airbag deployment performance in the event of an external shock may
be excellent. For example, the thickness thereof may be 3 to 4
mm.
[0293] In one embodiment, in the step of laminating the laminate
and the core layer together, the laminating may be achieved by
forming a second adhesive layer between the cushion layer of the
stack and the core layer. For example, the laminating may be
achieved by applying a second adhesive composition to one or more
of the lower surface of the cushion layer of the laminate and the
upper surface of the core layer and curing the applied composition
to form the second adhesive layer. The second adhesive composition
that is used here may be the same as that described above.
[0294] In one embodiment, the thickness of the second adhesive
layer may be 30 to 300 .mu.m. Within this thickness range, the
second adhesive layer may have excellent adhesion, and at the same
time, the airbag can be easily deployed through the skin layer in
the event of an external shock.
[0295] In one embodiment, the laminate and the core layer may be
laminated together by applying a primer to the surface of the core
layer, drying the applied primer to form a primer layer, applying
the second adhesive composition to each of the surface of the
primer layer and the surface of the cushion layer to be laminated,
and heating the applied composition. When the primer layer is
formed, the adhesion between the core layer and the second adhesive
layer may be excellent.
[0296] In one embodiment, the primer layer may have a thickness of
5 to 500 .mu.m. When the primer layer is formed to have this
thickness, the adhesion between the second adhesive layer and the
core layer may be excellent.
[0297] (S31) Covering Step
[0298] In one embodiment, the method may further include a step of
covering the fiber-based layer, the cushion layer and the core
layer with the skin layer, after the step of laminating the
laminate and the core layer together.
[0299] In the present disclosure, the covering means a process of
bringing the lower surface of the cushion layer of the laminate
into contact with the upper surface of the core layer, and then
covering the cushion layer and the core layer with the skin layer
of the laminate.
[0300] In one embodiment, after the laminate and the core layer are
laminated together and the laminated laminate and core layer are
pressed using a compression mold or the like, the fiber-based
layer, the cushion layer and the core layer may be covered with the
skin layer.
[0301] In one embodiment, the skin layer may not be subjected to a
skiving or scoring process. The crash pad of the present disclosure
allows the airbag to be easily deployed even when the skin
layer-weakening process (skiving or scoring process) is not
performed. Thus, under the above-described conditions, the skin
layer-weakening process may be eliminated, and thus the number of
processes can be reduced and excellent economic efficiency can be
obtained.
[0302] Hereinafter, the configuration and effects of the present
disclosure will be described in more detail with reference to
preferred examples. However, these examples are presented as
preferred examples of the present disclosure and may not be
construed as limiting the scope of the present disclosure in any
sense. The contents that are not described herein can be
sufficiently and technically envisioned by those skilled in the
art, and thus the description thereof will be omitted herein.
EXAMPLES AND COMPARATIVE EXAMPLES
Example 1
[0303] (1) Preparation of intermediate: A 1 to 6-mm-thick core
layer including polypropylene was prepared. In addition, a cushion
layer including slab foam was prepared, which was formed by foaming
a first composition including 40 to 75 wt % of a polyol compound,
15 to 45 wt % of an isocyanate-based curing agent and 1 to 15 wt %
of a foaming agent.
[0304] A primer was applied to the upper surface of the core layer
and dried to form a primer layer (thickness: 5 to 10 .mu.m).
[0305] A second adhesive composition including polyurethane was
applied to each of the lower surface of the cushion layer and the
upper surface of the primer layer to form a second adhesive layer
(thickness: 1 to 15 .mu.m) including water-dispersible
polyurethane, and then the lower surface of the cushion layer and
the upper surface of the primer layer were heat-cured and laminated
together, thereby preparing an intermediate.
[0306] (2) Lamination of fiber-based layer and skin layer onto
intermediate: A skin layer material was formed according to a
conventional method using a skin layer composition including 65 to
75 wt % of a polyol compound, 15 to 25 wt % of an isocyanate-based
curing agent and 10 to 15 wt % of a chain extender. Thereafter, a
skin layer having the thickness shown in Table 1 below was formed
by sewing the skin layer material through single-needle stitching
or double-needle stitching. At this time, the skin layer was not
subjected to a skiving or scoring process. On the lower surface of
the skin layer, a fiber-based layer (density: 0.22 to 0.27 g/cm3,
and thickness: 0.3-0.7 mm) in the form of a knitted fabric was
formed, including polyethylene terephthalate (PET) fiber.
[0307] Thereafter, a first adhesive composition was applied to the
lower surface of the fiber-based layer to form a first adhesive
layer (thickness: 30 to 300 .mu.m) including water-dispersible
polyurethane, and then the lower surface of the first adhesive
layer and the upper layer of the cushion layer of the intermediate
were laminated together and heat-dried.
[0308] (3) Covering with skin layer: The fiber-based layer, the
cushion layer and the core layer were covered with the skin layer,
thereby manufacturing a crash pad shown in FIG. 6.
Examples 2 to 4
[0309] Crash pads were manufactured in the same manner as in
Example 1, except that skin layers having the thicknesses and
physical properties shown in Table 1 below were applied.
Comparative Example 1
[0310] A crash pad was manufactured in the same manner as in
Example 1, except that a filament cloth having a thickness of 4 mm
was used instead of the slab foam as the cushion layer.
Comparative Examples 2 to 5
[0311] Crash pads were manufactured in the same manner as in
Example 1, except that skin layers having the thicknesses and
physical properties shown in Table 1 below were applied.
Test Example
[0312] (A) Evaluation 1 of Physical Properties
[0313] (1) Tensile Strength, Elongation and Tearing Strength of
Laminate of Skin Layer and Fiber-Based Layer
[0314] For a laminate of the skin layer and fiber-based layer of
the crash pad manufactured in each of the Examples and the
Comparative Examples, the tensile strength (kgf/cm2), elongation at
break (%) and tearing strength (kgf/cm) in the transverse direction
(TD) were measured at a test speed of 200 mm/min using an Instron
UTM instrument according to Hyundai Motors Specification
MS300-31.
[0315] (2) Adhesive Strength
[0316] For the skin layer/fiber-based layer laminate and first
adhesive layer of the crash pad manufactured in each of the
Examples and the Comparative Examples, the adhesive strength
(kgf/cm) was measured according to Hyundai-Kia Motors MS
Specification 256-29 (ISO 813 standard; 90.degree. peeling method;
peeling speed: 25 mm/min), and the results of the measurement are
shown in Table 1 below.
[0317] (3) Tensile Strength, Elongation and Tearing Strength of
Cushion Layer
[0318] For the cushion layer of the crash pad manufactured in each
of the Examples and the Comparative Examples, the tensile strength
(kgf/cm2), elongation at break (%) and tearing strength (kgf/cm)
were measured according to the JIS K6301 standard, and the results
of the measurement are shown in Table 1 below.
[0319] (4) Test for Evaluation of Airbag Deployment Performance
[0320] In accordance with Hyundai Motor ES84500-13 (passenger
airbag invisible door performance specification), a passenger
airbag (PAB) module was mounted in the crash pad manufactured in
each of the Examples and the Comparative Examples. Then, the
passenger airbag module was allowed to explode by applying an
electrical signal to an inflator detonator at room temperature
(21.degree. C.), low temperature (-35.degree. C.) and high
temperature (85.degree. C.). Thereafter, it was checked whether the
airbag moves toward the seam line groove intentionally formed on
the crash pad of each of the Examples and Comparative Examples and
is deployed through the seam line to the outside, and it was
checked whether crash pad pieces scatter during airbag deployment.
The results of the checking were recorded as "pass (P)" and "fail
(F)" and shown in Table 3 below.
[0321] (5) Evaluation of Heat Resistance
[0322] According to Hyundai Motors MS specification 256-29, the
crash pad of each of the Examples and the Comparative Examples was
left to stand at 110.degree. C. for 300 hours, and then the
appearance defects of the cushion layer, such as lifting and
peeling, were visually evaluated according to the following
criteria: pass (P): there are no defects; and fail (F): defects
such as lifting or peeling occurred. The results of the evaluation
are shown in Table 1 below.
TABLE-US-00001 TABLE 1 Example Comparative Example 1 2 3 4 1 2 3 4
5 Skin layer Laminate 0.6 0.5 0.7 0.65 0.6 0.6 0.6 0.6 0.6 and
fiber- thickness (mm) based layer Tensile strength 25 20 30 20 25
55 70 30 5 (kgf/3 cm) Elongation at 150 180 200 100 150 200 100 300
50 break (%) Tearing strength 4 5 3 5 4 4 4 3.5 2.5 (kgf/cm)
Adhesive strength (kgf/cm) 0.8 0.8 1.1 0.9 1.2 0.8 0.8 0.8 0.8
Cushion Cushion layer 4 4 4 4 4 4 4 4 4 layer thickness (mm)
Tensile strength 5.18 6.5 5.5 5.25 20 5.18 5.18 5.18 5.18
(kgf/cm.sup.2) Elongation at 100.5 120 104 112 50 100.5 100.5 100.5
100.5 breakage (%) Tearing strength 0.44 0.52 0.48 0.51 5 0.44 0.44
0.44 0.44 (kgf/cm) Airbag deployment performance: P P P P P F P F F
room temperature (21.degree. C.) Airbag deployment performance: P P
P P P F F F F low temperature (-35.degree. C.) Airbag deployment
performance: P P P P P F F F F high temperature (85.degree. C.)
Heat resistance P P P P P P P P P
[0323] Referring to the results shown in Table 1 above, it could be
seen that the crash pads of Examples 1 to 4 according to the
present disclosure had excellent mechanical properties and
interlayer adhesion, rapid airbag deployment was possible even when
a skin layer-weakening process such as skiving or scoring was not
applied thereto, and the shape of the door portion of the crash pad
after airbag deployment was good. However, it could be seen that,
in the case of Comparative Example 1 to which the cushion layer
different from that of the present disclosure was applied, and in
the case of Comparative Examples 2 to 5 which did deviate from the
physical property conditions of the skin layer of the present
disclosure, the airbag was not deployed rapidly or the airbag
deployment shape was poor, and the airbag deployment performance
deteriorated.
[0324] (B) Evaluation 2 of physical properties--evaluation of
reliability: For Example 1 representative of the Examples and the
Comparative Example 1, the reliability of the following items was
measured and the results of the evaluation are shown in Table 2
below.
[0325] (1) Heat Aging Resistance
[0326] For Example 1, a heat aging resistance test was performed
according to Hyundai Motors specification MS257-06. Specifically,
the heat aging resistance of a specimen of Example 1 was evaluated
by heating the specimen, allowing the specimen to stand at
110.degree. C. for 500 hours, and then measuring the tensile
strength and elongation at break of the specimen.
[0327] (2) Moisture Aging Resistance
[0328] For Example 1, a moisture aging resistance test was
performed according to Hyundai Motors specification MS257-06.
Specifically, the moisture aging resistance of a specimen of
Example 1 was evaluated by heating the specimen, allowing the
specimen to stand at 50.degree. C. and a relative humidity of 98RH
% for 168 hours, and then measuring the tensile strength and
elongation at break of the specimen.
[0329] (3) Hydrolysis Resistance (1)
[0330] For Example 1, a hydrolysis resistance test was performed
according to Hyundai Motors specification MS257-06. Specifically, a
specimen of Example 1 was heated and immersed in distilled water at
85.degree. C. for 96 hours, and then the tensile strength and
elongation at break of the specimen were measured.
[0331] (4) Hydrolysis Resistance (2)
[0332] For Example 1, a hydrolysis resistance test was performed
according to Hyundai Motors specification MS257-10. Specifically, a
specimen of Example 1 was heated and kept in a heat-resistant oven
at 120.degree. C. for 48 hours, and then the tensile strength and
elongation at break of the specimen were measured.
TABLE-US-00002 TABLE 2 Example (cushion layer) Heat aging Tensile
strength (kgf/cm.sup.2) 3.00 Change rate: -42% resistance
Elongation at break (%) 92.2 Change rate: -8.2% Moisture aging
Tensile strength (kgf/cm.sup.2) 4.82 Change rate: -6.9% resistance
Elongation at break (%) 103.8 Change rate: 3.3% Hydrolysis Tensile
strength (kgf/cm.sup.2) 4.04 Change rate: -21.9% resistance
Elongation at break (%) 98.7 Change rate: -1.8% (1) Hydrolysis
Tensile strength (kgf/cm.sup.2) 5.16 Change rate: -0.3% resistance
Elongation at break (%) 98.0 Change rate: -2.5% (2)
[0333] Referring to the results shown in Table 2 above, it could be
seen that Example 1 of the present disclosure had excellent
reliability such as heat aging resistance, moisture aging
resistance and hydrolysis resistance.
[0334] The present disclosure has been described with reference to
the disclosed embodiments. Those skilled in the art will appreciate
that the present disclosure can be implemented in modified forms
without departing from the essential features of the present
disclosure. Therefore, the disclosed embodiments should be
considered in descriptive sense only, not for purposes of
limitation. Therefore, the scope of the present disclosure is
defined not by the detailed description of the present disclosure
but by the appended claims, and all modifications within a range
equivalent to the scope of the appended claims should be construed
as being included in the present disclosure.
* * * * *