U.S. patent application number 12/679243 was filed with the patent office on 2010-12-09 for buffering and sound-absorbing member.
Invention is credited to Makoto Fujii, Masanori Ogawa.
Application Number | 20100307867 12/679243 |
Document ID | / |
Family ID | 40467596 |
Filed Date | 2010-12-09 |
United States Patent
Application |
20100307867 |
Kind Code |
A1 |
Ogawa; Masanori ; et
al. |
December 9, 2010 |
Buffering and Sound-Absorbing Member
Abstract
The object of the present invention is to provide a shock and
sound absorbing member having excellent shock and sound absorbing
properties for use of a car etc. The shock and sound absorbing
member comprises a core panel 2 onto which a plural number of
tubular cells 22 are formed lengthwise and widthwise, a base panel
3 being attached to one side of the core panel 2, and a porous
sheet 4 covering the other side of the core panel 2, the invading
sound waves being damped in the tubular cells 22 of the core panel
2, and then absorbed by the porous sheet 4, the ventilation
resistance of the porous sheet 4 being set to be in the range of
between 0.5 and 5.0 kPas/m.
Inventors: |
Ogawa; Masanori; (Aichi,
JP) ; Fujii; Makoto; (Aichi, JP) |
Correspondence
Address: |
COOPER & DUNHAM, LLP
30 Rockefeller Plaza, 20th Floor
NEW YORK
NY
10112
US
|
Family ID: |
40467596 |
Appl. No.: |
12/679243 |
Filed: |
September 20, 2007 |
PCT Filed: |
September 20, 2007 |
PCT NO: |
PCT/JP2007/068239 |
371 Date: |
March 19, 2010 |
Current U.S.
Class: |
181/288 |
Current CPC
Class: |
B32B 15/20 20130101;
B32B 2262/101 20130101; B32B 2307/718 20130101; B32B 27/36
20130101; B32B 2262/106 20130101; B32B 2307/20 20130101; B32B
2307/306 20130101; B32B 27/30 20130101; B32B 21/08 20130101; B32B
2266/025 20130101; B32B 2605/08 20130101; B32B 2262/0253 20130101;
B32B 5/18 20130101; B32B 27/22 20130101; B32B 2262/062 20130101;
B32B 21/02 20130101; B32B 2262/0246 20130101; B60R 13/0884
20130101; B32B 5/26 20130101; B32B 2262/0238 20130101; B32B
2307/3065 20130101; B32B 2262/103 20130101; B32B 5/022 20130101;
B32B 2266/0235 20130101; G10K 11/172 20130101; B32B 2262/0276
20130101; B32B 27/285 20130101; B32B 5/024 20130101; B32B 15/18
20130101; B32B 2262/105 20130101; B60R 13/0861 20130101; B32B
27/281 20130101; B32B 3/18 20130101; B32B 2262/065 20130101; B32B
27/12 20130101; B32B 27/32 20130101; B32B 2307/734 20130101; B32B
2307/21 20130101; B32B 27/08 20130101; B32B 15/08 20130101; B32B
2262/0261 20130101; B32B 27/322 20130101; B32B 27/286 20130101;
B32B 2266/0228 20130101; B32B 2307/102 20130101; B32B 2307/56
20130101; G10K 11/168 20130101; B32B 2266/0278 20130101; B32B 25/08
20130101; B32B 9/02 20130101; B32B 7/12 20130101; B32B 25/14
20130101; B32B 27/34 20130101; B60R 13/0838 20130101; B32B 5/026
20130101; B32B 2262/10 20130101; B32B 2255/26 20130101; B32B
2262/08 20130101; B32B 27/365 20130101 |
Class at
Publication: |
181/288 |
International
Class: |
E04B 1/82 20060101
E04B001/82 |
Claims
1. A shock and sound absorbing member comprising a core panel onto
which a plural number of tubular cells are formed lengthwise and
widthwise, a base panel being attached to one side of said core
panel, and a porous sheet covering the other side of said core
panel, wherein said core panel is made of a thermoplastic resin,
the ventilation resistance of said porous sheet being set to be in
the range of between 0.5 and 5.0 kPas/m.
2. A shock and sound absorbing member in accordance with claim 1,
wherein said thermoplastic resin core panel is manufactured by the
vacuum and/or pressure forming of a thermoplastic resin sheet.
3. A shock and sound absorbing member in accordance with claim 2,
wherein said thermoplastic resin sheet is drawn widthwise to a
prescribed degree before said thermoplastic resin sheet is molded
by vacuum and/or pressure forming.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a shock and sound absorbing
member to be arranged on such as the underside or upperside of a
car engine, floor, or the like.
BACKGROUND OF THE INVENTION
[0002] A shock and sound absorbing member, for instance, is
arranged on the underside of a car engine or compartment floor to
protect said engine or floor from small stones which are scattered
during the driving of the car, or to help prevent in-use exterior
noises or the like from invading the car compartment. Further,
depending on the car model, there is a case where said shock and
sound absorbing member is arranged on the upperside of the engine
(underneath of the engine hood).
[0003] Hitherto, as said shock and sound absorbing member, a
structure consisting of a base material and a sound absorbing
member made of a porous sheet, a structure consisting of a sound
absorbing member made of a porous sheet and a surface material, or
the like have been provided. [0004] Patent Literature 1: Tokkai
2002-086490 [0005] Patent Literature 2: Tokkai H11-254570
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0006] Said traditional shock and sound absorbing member performs
its shock and sound absorbing action with said air containing
porous sheet, but the effect of this shock and sound absorbing
performance using said porous sheet alone may be insufficient for
use in a car.
Means to Solve Said Problems
[0007] The object of the present invention is to provide a shock
and sound absorbing member having sufficient performance so as to
be a shock and sound absorbing member for a car, said shock and
sound absorbing member 1 comprising a core panel 2 onto which a
plural number of tubular cells are formed lengthwise and widthwise,
a base panel 3 being attached to one side of said core panel 2, and
a porous sheet 4 covering the other side of said core panel 2,
wherein said core panel 2 is made of a thermoplastic resin, the
ventilation resistance of said porous sheet being set to be in the
range of between 0.5 and 5.0 kPas/m. Generally, said thermoplastic
resin core panel 2 is manufactured by the vacuum and/or pressure
forming of a thermoplastic resin sheet 21. It is preferable that
said thermoplastic resin sheet be drawn widthwise to a prescribed
degree before said thermoplastic resin sheet 21 is molded by vacuum
and/or pressure forming.
EFFECT OF THE INVENTION
Action
[0008] Said shock and sound absorbing member 1 performs its shock
and sound absorbing action by said porous sheet having a
ventilation resistance in the range of between 0.5 and 5.0 kPas/m,
and further, performs its sound insulation action by damping
sound's energy, this being done by reflecting the sound waves
invading said tubular cells 22 of said core panel 2 onto the inner
walls of said tubular cells 22.
[0009] Said core panel 2, being made of said thermoplastic resin,
is preferably manufactured by vacuum and/or pressure forming, which
is suitable for mass production, and by which an article having a
complex shape can be molded.
[0010] When said thermoplastic resin sheet 2 is molded by vacuum
and/or pressure forming, in a case where said thermoplastic resin
sheet 21 is stretched widthwise to a prescribed degree before
vacuum and/or pressure forming, said thermoplastic resin sheet 21
may easily become elongated, as a result said thermoplastic resin
sheet 21 may elongate nearly uniformly conforming to the mold, so
that said thermoplastic resin sheet 21 can be uniformly molded in
the mold. In particular, in a case where a thermoplastic resin
having a high softening point such as engineering plastic is used
as the material for said core panel, said method wherein said
thermoplastic resin sheet 21 is drawn widthwise is effective.
Further, especially in a case where a thermoplastic resin which is
apt to cause a draw down phenomenon is used as a material, said
draw down phenomenon can easily be relieved by the drawing
widthwise of said thermoplastic resin sheet, and said thermoplastic
resin sheet can be uniformly molded in the mold.
EFFECT OF THE INVENTION
[0011] According to the present invention, a shock and sound
absorbing member which has excellent shock and sound absorbing
performance, and is easily manufactured, is provided.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a cross sectional view of a shock and sound
absorbing member.
[0013] FIG. 2 is a perspective view of a core panel onto which a
plural number of bottomless tubular rectangular cells are formed
lengthwise and widthwise.
[0014] FIG. 3 is a sectional view cutting along line B-B of said
core panel onto which a plural number of bottomless tubular
rectangular cells are formed lengthwise and widthwise.
[0015] FIG. 4 is a perspective view of a core panel onto which a
plural number of bottomed tubular rectangular cells are formed
lengthwise and widthwise.
[0016] FIG. 5 is a cross sectional view of a core panel onto which
a plural number of bottomed tubular rectangular cells are formed
lengthwise and widthwise.
[0017] FIG. 6 is a cross sectional view of a shock and sound
absorbing member from another embodiment.
[0018] FIG. 7 is an explanation view of the measurement theory of
ventilation resistance.
[0019] FIG. 8 shows graphs illustrating the results of the
performance tests of the shock and sound absorbing member in
EXAMPLES and COMPARISONS.
EXPLANATION OF CODES
[0020] 1. Shock and sound absorbing member [0021] 2. Core panel
[0022] 3. Base panel [0023] 4. Porous sheet
BEST MODE FOR CARRYING OUT THE INVENTION
[0024] The present invention is described in details below.
[0025] Said shock and sound absorbing member 1 of the present
invention comprises, for instance, a core panel 2, a base panel 3
attached to one side of said core panel 2, and a porous sheet 4
covering the other side of said core panel 2 as shown in FIG.
1.
[Core Panel]
[0026] For instance, said core panel 2 of the present invention has
a structure in which a plural numbers of tubular cells 22 are
formed lengthwise and widthwise on a panel 21 as shown FIGS. 2, and
3. To manufacture said core panel 2, a thermoplastic resin sheet 21
is molded by vacuum and/or pressure forming to form a plural number
of bottomed tubular rectangular cells on said thermoplastic resin
sheet 21 as shown in FIGS. 4 and 5, and if desired, the bottoms of
said bottomed tubular rectangular cells can be removed by cutting
to form bottomless tubular rectangular cells as shown in FIGS. 2
and 3.
[0027] The material used in said core panel is a thermoplastic
resin such as polystyrene (PS), acrylonitrile-styrene copolymer
(AS), acrylonitrile-butadiene-styrene copolymer (ABS),
acrylonitrile-ethylene-styrene copolymer (AES), polyethylene (PE),
polypropylene (PP), polymethyl methacrylate (PMMA),
ethylene-propylene copolymer (EPR), polyvinyl chloride (PVC),
polyvinylidene chloride, ethylene-vinyl acetate copolymer, modified
polypropylene that is PP modified to PE and/or EPR (modified PP),
or the like, or a polymer alloy or a polymer blend containing two
or more kinds of said thermoplastic resin, and further, said
material is a thermoplastic type engineering plastic such as
polyamide (PA), polyester, polyacetal (POM), polycarbonate (PC),
polyethylene telephthalate (PET), polybutylene telephthalate (PBT),
polysulfone (PSF), polyether sulfone (PES), polyphenylene ether
(PPE), polyphenylene sulfide (PPS), polyarylate (PAR), polyether
ether ketone (PEEK), polyamide imide (PAI), polyimide (PI),
polyether imide (PEI), polyaminobismaleimide, methylpentene
copolymer (TPX), cellulose acetate (CA), or the like, or a liquid
crystal type engineering plastic such as polyallylether, or the
like, or a compression molding type engineering plastic such as
polytetrafluoroethylene (PTFE), or the like, or other engineering
plastic such as amorphous polymer, polyaminobismaleimide, and
bismaleimide-triazine group thermosetteing type aromatic polyimide,
or the like, or a polymer alloy or a polymer blend containing two
or more kinds of said engineering plastic, or a polymer alloy
containing one or more kind(s) of said engineering plastic, and one
or more kind(s) of thermoplastic resin such as polystyrene (PS),
polypropylene (PP), or modified PP, or a polymer alloy wherein one
or more kind(s) of thermoplastic elastomer and/or synthetic rubber
is (are) further added to said polymer alloy.
[0028] Said thermoplastic elastomer and/or synthetic rubber is/are,
for instance, a block copolymer such as a styrenic thermoplastic
elastomer, butadiene-styrene block copolymer styrene-rubber
intermediating block-styrene copolymer or the like, and said
thermoplastic elastomer and/or synthetic rubber is/are such as
polyester, polyester acrylate, acryl rubber (AR), butyl rubber,
silicone rubber, urethane rubber (UR), fluoride rubber, polysulfide
rubber, graft rubber, butadiene rubber (BR), polybutadiene,
isoprene rubber (IR), polyisoprene, chloroprene rubber (CR),
polyisobutylene rubber (IBR), polybutene rubber, thiokol rubber,
polysulfide rubber, polyether rubber, epichlorohydrin rubber,
norbornene terpolymer, polybutadiene chain-end modified to hydroxy
or carboxyl group, partial hydrogenation styrene-butadiene block
copolymer, chlorosulfide rubber, isobutene-isoprene rubber (IIR),
acrylate-butadiene rubber (ABR), styrene-butadiene rubber (SBR),
acrylonitrile-butadiene rubber (NBR), pyridine-butadiene rubber,
styrene-isoprene rubber (SIR), styrene-ethylene copolymer,
polystyrene-polybutadiene-polystyrene (SBS),
polystyrene-polyisoprene-polystyrene (SIS),
poly(.alpha.-methylstyrene)-polybutadiene-poly(.alpha.-methylstyrene)
(.alpha.-MeSB.alpha.-MeS),
poly(.alpha.-methylstyrene)-poly-isoprene-poly(.alpha.-methylstyrene),
ethylene-propylene copolymer (EP), butadiene-styrene copolymer
(EP), ethylene-propylene-ethylidene copolymer,
ethylene-propylene-diene copolymer, ethylene-propylene copolymer
rubber, ethylene-1-butene copolymer rubber,
ethylene-propylene-ethylidenenorbornene copolymer rubber,
ethylene-propylene-dicyclopentadiene copolymer rubber,
ethylene-propylene-1,4-hexadiene copolymer rubber,
ethylene-1-butene-ethylidenenorbornene copolymer rubber,
ethylene-1-butene-dicyclopentadiene copolymer rubber,
ethylene-1-butene-1,4-hexadiene copolymer rubber,
acrylonitrile-chloroprene rubber (NCR), styrene-chloroprene rubber
(SCR), styrene-butadiene-styrene (SBS) copolymer,
styrene-isoprene-styrene (SIS) copolymer, styrene-hydrogenation
polyolefin-styrene (SEBS) copolymer, or the like. Still further, a
biodegradable polymer made of such as a polylactic acid,
cornstarch, sugar cane starch or the like may be added to said
polymer alloy. The preferable material for said thermoplastic resin
is a polymer alloy of said engineering plastic or modified PP.
[0029] Polyethylene (PE) is usable to modify PP, and any kind of PE
such as a high density PE, the density of which is higher than
0.941, a medium density PE, the density of which is in the range of
between 0.926 and 0.940, a low density PE, the density of which is
in the range of between 0.910 and 0.925, and an ultra low density
PE, the density of which is lower than 0.909 are usable to modify
PP, said low density PE being preferable since said low density PE
has a good compatibility with PP, and greatly improves the
elongation of modified PP.
[0030] Further, ethylene-propylene rubber (EPR) is usable to modify
PP, and any EPR such as ethylene-propylene rubber-like copolymer,
ethylene-propylene-diene terpolymer (EPDM) into which (a) diene
component(s) such as cyclopentadiene, ethylidenenorobornene,
1,4-hexadiene, or the like is(are) copolymerized, is(are) usable to
modify PP.
[0031] As described above, the preferable thermoplastic resin to be
used as a material for said core panel is modified PP, and into
said modified PP, PE and/or EPR is(are) compounded in the range of
between 5 and 30% by mass. In a case where PE and/or EPR is (are)
compounded into said PP at below 5% by mass, improvement in the
elongation property of said PP will be insufficient, and good
moldability can not be guaranteed.
[0032] Further, in a case where PE and/or EPR is (are) compounded
into said PP at over 30% by mass, the hardness of the
resulting-modified PP may be insufficient, degrading said modified
PP's shape and dimensional stability, and heat resistance.
[0033] If necessary, one or more kind(s) of thermoplastic resin may
be mixed into said modified PP. Said thermoplastic resin is such as
a polyvinyl chloride group resin, acrylic resin, methacrylic resin,
polyvinylidene chloride group resin, polyvinyl propionate group
resin, polyester group resin, or the like.
[0034] Commonly said modified PP is provided as a sheet, and a
thermoplastic film or a foamed thermoplastic resin sheet may be
formed on one side or both sides of said modified PP sheet. Said
thermoplastic resin sheet may be a sheet of a thermoplastic resin,
for instance, polyolefin such as PE, unmodified PP, EPR,
ethylene-vinyl acetate copolymer, or the like, a polyvinyl chloride
group resin, acrylic resin, methacrylic resin, polyvinylidene
chloride group resin, polystyrene group resin, polyvinyl propionate
group resin, styrene-butadiene copolymer, polyester group resin, or
the like. From the view point of interlaminar strength, or heat
resistance, unmodified PP film is preferable. Said film on said
modified PP sheet improves the surface flatness and chemical
resistance of said core panel 2, especially in a case where an
inorganic filler is mixed into said modified PP.
[0035] One or more kind(s) of inorganic filler may be mixed into
said thermoplastic resin as the material for said core panel, to
improve the mechanical strength and the heat resistance of said
core panel. Said inorganic filler may be such as a calcium
carbonate, magnesium carbonate, barium sulphate, calcium sulphate,
calcium sulphite, calcium phosphate, calcium hydroxide, magnesium
hydroxide, aluminium hydroxide, magnesium oxide, titanium oxide,
iron oxide, zinc oxide, alumina, silica, diatomaceous earth,
dolomite, gypsum, talc, clay, asbestos, mica, calcium silicate,
bentonite, white carbon, carbon black, iron powder, aluminium
powder, glass powder, stone powder, blast furnace slag, fly ash,
cement, zirconia powder, or the like.
[0036] Further, one or more kind(s) of organic filler or fibrous
filler may be mixed into said thermoplastic resin as material(s)
for said core panel to improve its shape and dimensional stability,
compression and tensile strength, or the like. Said organic filler
is such as linter, linen, sisal, wood flour, coconut shell flour,
walnut powder, starch, wheat flour, or the like, and said fibrous
filler is a natural fiber such as cotton, hemp, bamboo fiber, palm
fiber, wool, asbestos, kenaf fiber, or the like, a synthetic resin
fiber such as a polyamide fiber, polyester fiber, polyolefin fiber,
acrylic fiber, polyvinyl chloride fiber, polyvinylidene chloride
fiber, or the like, a semi-synthetic resin fiber such as viscose
fiber, acetate fiber, or the like, inorganic fiber such as asbestos
fiber, glass fiber, carbon fiber, ceramic fiber, metal fiber,
whisker, or the like. Generally said organic or inorganic filler or
said fibrous filler is added to said thermoplastic resin in an
amount in the range of between 0.05 and 200% by mass.
[0037] Said thermoplastic resin may be colored with pigment or dye
stuff to distinguish it, and further plasticizers such as dioctyl
phthalate (DOP), dibutyl phthalate (DBP), or the like,
antioxidants, antistatic agents, crystallizers, fire retardants,
flameproof agents, insecticides, preservatives, wax, lubricants,
stabilizer, antioxidants, ultraviolet absorbers, foaming agents
such as chemical foaming agent, capsule type foaming agent, or the
like may be added to said thermoplastic resin. One or more kind(s)
of said component may be added to said thermoplastic resin.
[0038] Generally, the thickness of said thermoplastic resin sheet
21 is set to be in the range of between 0.1 and 1.0 mm, preferably,
0.3 and 0.5 mm, and in a case where said thermoplastic resin is
said modified PP, the thickness of said film formed on said sheet
21 is generally set to be in the range of between 10 and 100 .mu.m.
Further, said thermoplastic resin sheet may be a foamed
thermoplastic resin sheet.
[0039] To manufacture said core panel 2 of the present invention,
said thermoplastic resin sheet 21 is heated to soften and then
introduced into a vacuum and/or pressure forming machine so as to
mold it by said vacuum and/or pressure forming. Said thermoplastic
resin sheet 21, heated and softened, is preferably drawn widthwise
(cross direction to the introduction direction of said
thermoplastic resin sheet 21 into said vacuum and/or pressure
forming machine) to a prescribed degree before said thermoplastic
resin sheet 21 is introduced into the vacuum and/or pressure
forming machine, namely before molding.
[0040] In a case where said thermoplastic resin sheet 21 is
introduced into said vacuum and/or pressure forming machine without
stretching, uniform elongation of said thermoplastic resin sheet 21
during molding can not be realized, and it is feared that a molded
article having a uniform thickness can not be manufactured because,
for instance, the thickness of the deep drawing part(s) of said
molded article becomes thin, while the thickness of other part(s)
increases.
[0041] On the contrary, in a case where said thermoplastic resin
sheet 21, having been heated and softened, is stretched beforehand,
said thermoplastic resin sheet 21 may elongate more easily, that is
to say, said thermoplastic resin sheet 21 may be put in such a
condition that said thermoplastic resin sheet 21 can easily be
elongated, so that the stress of elongation propagates uniformly to
the entire area of said thermoplastic sheet 21 in said vacuum
and/or pressure forming machine. Accordingly, the resulting molded
article (in this case core panel 2) has highly uniform thickness as
a whole, and in a case where said thermoplastic resin sheet 2,
which has been stretched widthwise, is deep drawn, the deep drawn
part(s) of said thermoplastic sheet 2 becomes difficult to thin
out, causing the problem of tearing, and the like, so that said
core panel having a plural number of tubular cells 22A shown in
FIG. 4 is easily molded.
[0042] The degree of stretching widthwise said thermoplastic resin
sheet 21 is preferably set to be in the range of between 1% and 5%
of the original width of said thermoplastic resin sheet 21. In a
case where the degree of stretching is below 1% of the original
width, said thermoplastic resin sheet will be harder to elongate,
and the drawing down phenomenon of said thermoplastic sheet 21 when
said thermoplastic sheet 21 is heated to mold, can not be
completely dissolved.
[0043] In a case where the degree of stretching is beyond 15% of
the original width, the thickness of said thermoplastic resin sheet
21 will be reduced before molding, and there is a possibility that
said thermoplastic resin sheet may tear during the molding
process.
[0044] To manufacture said core panel of the present invention,
other molding methods besides said vacuum and/or pressure forming
such as press molding, injection molding, or the like can be
applied.
[0045] The thickness of said core panel 2 is preferably set to be
in the range of between 5 and 100 mm. The thickness of said core
panel 2 corresponds to the height of said tubular cells 22 (in FIG.
3, the height of said tubular cells 22 is shown as "h"), and said
tubular cells 22 having a height of around h can attenuate sound
waves preferably by reflecting the sound waves invading said
tubular cells 2 onto the inner walls of said tubular cells.
[0046] In a case where the height h of said tubular cells 22 is
below 5 mm, it is feared that the sound waves invading said tubular
cells 22 will travel through said tubular cells 22 without
reflecting on the inner walls of said tubular cells 22.
[0047] On the contrary, in a case where the height h of said
tubular cells 22 is beyond 100 mm, the thickness of the resulting
shock and sound absorbing member 1 will increase, and according to
the increase in the thickness of said shock and sound absorbing
member 1, the volume of said shock and sound absorbing member 1 has
increased, hence also increasing the amount of space in the car to
fit said shock and sound absorbing member 1.
[0048] In the embodiment shown in FIG. 1 the bottom of said
bottomed tubular cell 22 is cut out to form a bottomless tubular
cell, however in the present invention, said base panel 3 may be
attached to the bottom side of said bottomed tubular cell without
cutting out its bottom, and said porous sheet 4 may cover the
opposite side of said core panel 4.
[0049] In this embodiment, the tubular rectangular cells 22, 22A
are formed on said core panels 21, but instead of said tubular
rectangular cells 22, 22A, any shape of tubular cell such as
cylindrical tubular cell, or hexagonal tubular cell may be formed
on said core panel.
[Base Panel]
[0050] Said base panel 3 used in the present invention includes a
panel or a molded article made of a rigid plastic such as PS, AS,
ABS, AES, PP, modified PP, PVC, PC, PMMA, PSF, PES, PPO, PPS, PAR,
PEEK, PAI, PI, PEI, melamine resin, phenol resin, or the like, or a
foamed panel made of said rigid plastic, or a woody panel such as
wooden board, plywood, hard board, particle board, medium-density
fiberboard (MDF), or the like, or a metal panel made of a metal
such as aluminium, iron, steel, titanium, or the like, or a alloy
such as duralumin, stainless steel, or the like, or a molded porous
sheet used in the present invention. Said base panel 3 invests the
shock and sound absorbing member of the present invention with
sound absorbing and insulating properties, and rigidity.
[Porous Sheet]
[0051] A porous sheet 4 covers one side of said core panel 2 of the
present invention as shown in FIG. 1. The material of said porous
sheet 4 is a fiber aggregate such as a knit or woven fiber sheet,
nonwoven fabric, felt, or a laminated sheet of said fiber sheet, or
the like, and the fiber used in said fiber aggregate is, for
instance, a synthetic fiber such as polyester fiber, polyethylene
fiber, polyamide fiber, acrylic fiber, polyurethane fiber,
polyvinyl chloride fiber, polyvinylidene chloride fiber, acetate
fiber, or the like, a natural fiber such as pulp, cotton, palm
fiber, hemp fiber, bamboo fiber, kenaf fiber, or the like, an
inorganic fiber such as glass fiber, carbon fiber, ceramic fiber,
asbestos fiber, or the like, a reclaimed fiber obtained by the
defibrating of the scraps of the fiber product made of said fiber,
or the like, said fiber being used singly or two or more kinds of
fiber may be used in said fiber aggregate. Further, as the material
of said porous sheet, a well known foamed plastic having an
interconnecting structure, a sintering plastic beads, or the like
is used. Said foamed plastic having an interconnecting structure is
such as polyurethane foam (include flexible polyurethane foam, hard
polyurethane foam), foamed polyolefin such as polyethylene foam,
polypropylene foam, or the like, polyvinyl chloride foam,
polystyrene foam, foamed amino plastic resin such as foamed
melamine resin, foamed urea formaldehyde resin, or the like, a
foamed epoxy resin, a foamed phenol group resin comprising phenolic
compounds such as monohydric phenol, polyhydric phenol or the
like.
[0052] The ventilation resistance of said porous sheet 4 is set to
be in the range of between 0.5 and 5.0 kPas/m. Said porous sheet 4
having a ventilation resistance in the range described above gives
the shock and sound absorbing member of the present invention good
shock and sound absorbing properties.
[0053] Said ventilation resistance R (kPas/m) is a barometer
expressing the degree of air travelling through the material. To
measure said ventilation resistance R, a steady flow pressure
differential measuring method may be applied. As shown in FIG. 7, a
test piece T is arranged in a cylindrical duct W, and while air
travels through said duct at a constant flow, as shown by an arrow,
the difference in pressure in said duct between inlet side P1, and
outlet side P2 is measured. The ventilation resistance is
calculated using the following formula.
R=.DELTA.P/V
[0054] Herein .DELTA.P represents the difference in pressure
Pa(.DELTA.P-P1-P2), and V represents the volume of air flow for
said unit cross section area of said duct (m3/m2S). Said
ventilation resistance R (Pas/m) has the following relationship
with the ventilation degree C. (m/Pas) of C=1/R.
[0055] Said ventilation resistance can be measured with such as the
ventilation tester (Tester Name: KES-F8-AP1, KATO TECH CO., LTD.
The steady flow pressure-differential measuring method).
[0056] Synthetic resin may be impregnated into said porous sheet 4
in so far as the ventilation property of said porous sheet is
retained. Said synthetic resin may include, for instance, a
precondensate of a thermosetting resin such as melamine group
resin, urea group resin, phenol group resin, or the like and
thermoplastic resin or said synthetic resin is provided as an
emulsion, water solution, or the like.
[0057] Further, in a case where fire resisting or nonflammable
fiber, for instance, an inorganic fiber such as carbon fiber, glass
fiber, ceramic fiber, or the like, a mineral fiber such as asbestos
fiber, or the like, an aramid fiber (aromatic polyamide fiber), an
animal hair such as sheep wool (natural wool) or the like is used
as the material for said porous sheet, said shock and sound
absorbing member 1 can acquire fire resistance or nonflamability
without using a flame retardant agent. Flame retardant agents are
described below.
[Flame Retardant Agents]
[0058] Further, a flame retardant may be added to said porous sheet
4. Said flame retardant is, for instance, such as flame retardant
containing phosphorus, flame retardant containing nitrogen, flame
retardant containing sulfur, flame retardant containing boron,
flame retardant containing bromine, guanidine group flame
retardant, phosphate group flame retardant, phosphoric ester flame
retardant, amine resin group flame retardant, or the like.
[0059] A powdery flame retardant, which is insoluble or difficult
to dissolve in water, is especially advantageous when used in the
present invention.
[0060] Said powdery flame retardant, which is insoluble or
difficult to dissolve in water, imparts a flame retardancy having
excellent water resistance and durability to said porous sheet 4.
In particular, since said porous sheet of the present invention has
a thin structure, said powdery solid flame retardant can be
smoothly impregnated into the inside of said fiber sheet, so that
said fiber sheet will gain high flame retardancy to
non-flammability.
[0061] A desirable flame retardant is a capsulated ammonium
polyphosphate covered with melamine, urea, or the like, though
price-wise the most desirable flame retardant is ammonium
polyphosphate, which has an average degree of polymerization in the
range of between 10 and 40. Said ammonium polyphosphate having said
average degree of polymerization, is difficult to dissolve, or
insoluble in water, and decomposes at a high temperature, to
produce a gas which is flame retardant, said flame retardant gas
having low toxicity to humans and animals.
[0062] Herein said average degree n of polymerization of ammonium
polyphosphate is calculated using the following formula 1.
n = 2 .times. P mol N mol - P mol [ Formula 1 ] ##EQU00001##
[0063] Wherein P mol shows the mole number of phosphorus contained
in said ammonium polyphosphate, N mol shows the mole number of
nitrogen, and the P mol and N mol are each calculated using the
following formulae.
P mol = P content ( % by mass ) / 100 Atomic weight of P ( 30.97 )
[ Formula 2 ] N mol = N content ( % by mass ) / 100 Atomic weight
of N ( 14.01 ) [ Formula 3 ] ##EQU00002##
[0064] The analysis of the P content is carried out using, for
example, an IPC emission spectrochemical analysis, with an analysis
of the N content being carried out using, for example, a CHN
measurement method.
[0065] In a case where the ammonium polyphosphate has an average
degree of polymerization greater than 10, said ammonium
polyphosphate is almost insoluble in water, while in a case where
said ammonium polyphosphate has an average degree of polymerization
beyond 40, when said ammonium polyphosphate is dispersed in water
or an aqueous dispersion medium, the viscosity of the resulting
dispersion increases remarkably, so that in a case where said
dispersion is applied to or impregnated into said porous sheet, it
will be is difficult to uniformly coat or impregnate said porous
sheet with said dispersion, and as a result, it is not guaranteed
to provide a porous sheet with excellent flame retardancy.
[0066] In the present invention, as said powdery solid flame
retardant, an expandable graphite may be used with said ammonium
polyphosphate.
[0067] The expandable graphite used in the present invention is
produced by soaking a natural graphite in an inorganic acid such as
concentrated sulfuric acid, nitric acid, selenic acid or the like,
and then treating it with an oxidizing agent such as perchloric
acid, perchlorate, permanguate, bichromate, hydrogen peroxide or
the like, said expandable graphite having an expansion start
temperature in the range of between about 250 and 300.degree. C.
The expansion volume of said expandable graphite is in the range of
between about 30 and 300 ml/g, its particle size being in the range
of between about 300 and 30 mesh.
[0068] In a case where the synthetic resin solution or emulsion is
impregnated into or applied to said porous sheet, or in a case
where the synthetic resin is mixed into said porous sheet, said
powdery solid fire retardant such as ammonium polyphosphate,
expandable graphite, or the like may be commonly mixed into said
synthetic resin solution or emulsion. Any mixing ratio can be
applied, but commonly 0.5 to 100% by mass of said ammonium
polyphosphate, or in the case of said expandable graphite being
used, 0.5 to 50% by mass of said expandable graphite is mixed in
with said porous sheet.
[0069] In a case where said synthetic resin is a water solution, a
water soluble resin is preferably dissolved in said water solution.
Said water soluble resin may include such as sodium polyacrylate,
partial saponified polyacrylate, polyvinylalcohol, carboxymethyl
cellulose, methyl cellulose, ethyl cellulose, hydroxyethyl
cellulose, or the like. Further, an alkali soluble resin such as a
copolymer of acrylate and/or methacrylate, and an acrylic acid
and/or methacrylic acid, or a slightly cross-linked copolymer of
the above mentioned copolymer, or the like may be used as said
water soluble resin of the present invention. Said copolymer or
said slightly cross-linked copolymer is commonly provided as an
emulsion.
[0070] In a case where said water soluble resin is dissolved in
said synthetic resin water solution, said water solution may be
thickened to improve the stability of dispersion, making it
difficult for said ammonium polyphosphate and said expandable
graphite sediment, thus preparing a uniform dispersion.
[0071] Further, the adhesiveness of said ammonium polyphosphate and
expandable graphite to said fibers may be improved by said water
soluble resin, preventing the release of said ammonium
polyphosphate and expandable graphite from said fiber sheet.
[0072] Said water soluble resin may be commonly added to said water
solution in an amount in the range of between 0.1 and 20% by mass
as a solid.
[0073] Further, to add said powdery solid flame retardant, such as
said ammonium polyphosphate, or expandable graphite to said porous
sheet, a dispersion of said ammonium polyphosphate, or expandable
graphite may be applied to or impregnated into said porous sheet,
after said synthetic resin has been impregnated into said porous
sheet, wherein said dispersion has been prepared by dispersing said
ammonium polyphosphate, or expandable graphite into said synthetic
resin aqueous solution of water soluble resin such as sodium
polyacrylate, partially saponified polyacrylate, polyvinylalchohol,
carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose,
hydroxyethyl cellulose or the like, or into a synthetic resin
emulsion such as an emulsion of alkali soluble resin such as a
copolymer of acrylate and/or methacrylate, and acrylic acid and/or
methacrylic acid, or a slightly cross linked copolymer as described
above, or the like.
[0074] To disperse said powdery solid flame retardant of said
ammonium polyphosphate, expandable graphite, or the like into said
synthetic resin emulsion or aqueous solution, a homomixer, a
supersonic wave type emulsifying machine or the like is preferably
used.
[0075] In a case where a supersonic type emulsifying machine is
used, said powdery solid flame retardant of said ammonium
polyphosphate, or expandable graphite, or the like is uniformly
dispersed in said aqueous solution or synthetic resin emulsion. In
particular, said expandable graphite is powdered by the supersonic
effect, and in a case where said synthetic resin emulsion or
aqueous solution into which said powdered expandable graphite has
been uniformly dispersed is impregnated into a porous sheet, said
expandable graphite will easily penetrate to the inside of said
porous sheet, because said porous sheet has a thin structure as
mentioned before, improving the flame retardancy of said porous
sheet.
[Manufacture of Said Shock and Sound Absorbing Member]
[0076] To manufacture said shock and sound absorbing member of the
present invention, said base panel 3 is attached to one side of
said core panel 2 and the other side of said core panel 2, is
covered with said porous sheets 4. To combine said base panel 3
with said core panel 2, or said porous sheet 4 with said core panel
2, generally a screw or clip can be used and further an adhesive,
hot melt adhesive, or ultrasonic welding, high frequency welding,
or heat welding, or the like can be used.
[0077] Said shock and sound absorbing member 1 of the present
invention is generally arranged so as to face said porous sheet 4
of said shock and sound absorbing member 1 toward the noise source
such as the engine etc., and said base panel 3 is arranged on the
opposite side of said porous sheet 4.
EXAMPLES
[0078] The present invention is concretely described by the
following EXAMPLES. The scope of the present invention, however, is
not limited by these EXAMPLES
(Material Samples Used in Examples)
(Manufacture of the Porous Sheet)
(Porous Sheet A)
[0079] A fiber mixture containing 50 parts by mass of a polyester
fiber (fineness: 2.2 dtex, fiber length: 75 mm), 10 parts by mass
of a hollow polyester fiber (fineness: 15 dtex, fiber length: 75
mm), and 40 parts by mass of a core-shell type polyester composite
fiber (fineness: 4.4 detex, fiber length: 55 mm, melting point of
the shell component: 150.degree. C.) as a fiber having a low
melting point, was used.
[0080] Said fiber mixture was opened by an opening machine to be
web-like, and the resulting opened web-like fiber mixture was then
needle punched. The resulting needle punched web sheet was then
introduced into a heating oven at 180.degree. C. to melt said low
melting point fiber and adjust the thickness of said needle punched
web sheet, to obtain a porous sheet A with a thickness of 5 mm, and
a unit weight of 1500 g/m.sup.2. The ventilation resistance of the
resulting porous sheet A was 3.8 kPas/m.
(Porous Sheet B)
1. Base Sheet B1
[0081] A fiber mixture containing 60 parts by mass of a polyester
fiber (fineness: 2.2 dtex, fiber length: 75 mm), 10 parts by mass
of a polypropylene fiber (fineness: 1.5 detex, fiber length: 55
mm), and 30 parts by mass of a core-shell type polyester composite
fiber (fineness: 4.4 dtx, fiber length: 55 mm melting point of the
shell component: 150.degree.C.) as a fiber having a low melting
point, was used, obtaining a base sheet B1 made of a porous sheet
with a thickness of 15 mm and a unit weight of 800 g/m.sup.2 in the
same manner as applied for said porous sheet A.
2. Surface Sheet B2
[0082] (1) A nonwoven fabric made of a polyester fiber (made by the
needle punching method, unit weight: 80 g/m.sup.2) was used as a
green sheet B2.alpha..
[0083] (2) A mixture solution containing 30 parts by mass of a
resol type phenol-alkylresorcin-formaldehyde precondensation
polymer (solid content: 50% by mass water solution), 1 part by mass
of a carbon black (solid content: 30% by mass water dispersion), 2
parts by mass of a fluorine group water and oil repellent agent
(solid content: 20% by mass water solution) and 67 parts by mass of
water was prepared as a coating solution B2.beta..
[0084] (3) Said coating solution B2.beta. was then applied to and
impregnated into said green sheet B2.alpha., the amount of coating
being adjusted to be 30% by mass by a roll coater, following which
said green sheet B2.alpha., which said coating solution B2.beta.
was applied to and impregnated into, was dried at 150.degree. C.
for 3 minutes, to obtain a surface sheet B2.
3. Lamination
[0085] A polyamide copolymer powder (particle size: 200 to 250
.mu.m, melting point 130.degree. C.) as a hotmelt adhesive was
scattered onto the surface of said base sheet B1 in a coating
amount of 5 g/m.sup.2. After this, said surface sheet B2 was put
onto the surface of said base sheet B1, and then the surface of
said surface sheet B2 was pressed by a heating roll (surface
temperature: 180.degree. C.) to attach said surface sheet B2 to
said base sheet B1 adjusting the thickness, to obtain a porous
sheet B with a thickness of 10 mm. The ventilation resistance of
said porous sheet B was 2.5 kPas/m.
(Porous Sheet C)
1. Base Sheet C1
[0086] (1) A fiber mixture containing 20 parts by mass of a
polyester fiber (fineness: 4.4 dtex, fiber length: 60 mm), 70 parts
by mass of a carbon fiber (fineness: 1.2 dtex, fiber length: 70
mm), and 10 parts by mass of a core-shell type polyester composite
fiber as a fiber having a low melting point (fineness: 4.4 dtex,
fiber length: 55 mm, melting point of the shell component:
150.degree. C.) was used, and a green sheet C1.alpha. with a
thickness of 10 mm and unit weight of 700 g/m.sup.2 was obtained by
the same method as applied to obtain said porous sheet A.
[0087] (2) A mixture solution containing 30 parts by mass of a
resol type phenol-alkyl resorcin-formaldehyde precondensation
polymer (solid content 50% by mass water solution), 1 part by mass
of a carbon black (solid content: 30% by mass water dispersion), 10
parts by mass of polyammonium phosphate as a flame retardant agent
(particle size: 40 to 50 nm, average polymerization degree: n=30),
5 parts by mass of an expandable graphite as a flame retardant
agent (particle size: 100 mesh, the temperature to start expansion:
280.degree. C., the expansion volume: 200 ml/g), 0.1 part by mass
of a sodium polyacrylate, and 53.9 parts by mass of water was
stirred by a homomixer, to prepare a uniform coating solution
C1.beta..
[0088] (3) Said coating solution C1.beta. was applied to and
impregnated into said green sheet C1.alpha., the amount of coating
being adjusted to be 30% by mass by a roll canter, and then said
green sheet C1.alpha., which said coating solution C1.beta. was
applied to and impregnated into, was dried at 160.degree. C. for 10
minutes, to obtain a base sheet C1 made of a porous sheet.
2. Surface Sheet C2
[0089] (1) A nonwoven fabric made of a polyester fiber (made by the
spunbonding method, unit weight: 30 g/m.sup.2) was used as a green
sheet C2.alpha..
[0090] (2) A mixture solution containing 30 parts by mass of a
resol type phenol-alkyl resorcin-formaldehyde precondensation
polymer (solid content: 50% by mass water solution), 1 part by mass
of a carbon black (solid content: 30% by mass water dispersion), 2
parts by mass of a fluorine group water and oil repellent agent
(solid content: 20% by mass water solution), and 67 parts by mass
of water was prepared as a coating solution C2.beta..
[0091] (3) Said coating solution C2.beta. was then applied to and
impregnated into said green sheet C2.alpha., the amount of coating
being adjusted to be 20% by mass by a roll coater, following which
said green sheet C2.alpha., which said coating solution C2.beta.
was applied to and impregnated into was dried at 150.degree. C. for
2 minutes, to obtain a surface sheet C2.
3. Lamination
[0092] Said surface sheet C2 was then put onto the surface of said
base sheet C1, and the resulting laminated sheet was molded by hot
pressing at 150.degree. C. for 2 minutes, to obtain a porous sheet
C with a thickness of 5 mm.
[0093] The ventilation resistance of said porous sheet C was 1.1
kPas/m.
[Porous Sheet D]
1. Base Sheet D1
[0094] A base sheet D1 with a thickness of 5 mm and unit weight of
500 g/m.sup.2 was obtained in the same manner as applied to obtain
said porous sheet A, with the exception that a fiber mixture
containing 45 parts by mass of a polyester fiber (fineness: 4.4
dtex, fiber length: 75 mm), 5 parts by mass of a hollow polyester
fiber (fineness: 15 dtex, fiber length: 75 mm), and 50 parts by
mass of a core-shell type polyester composite fiber as a fiber
having a low melting point (fineness: 4.4 dtex, fiber length: 55
mm, melting point of the shell component 130.degree. C.) was used,
and the temperature in the heating oven was set to be 150.degree.
C.
2. Surface Sheet D2
[0095] (1) A nonwoven fabric made of a polyester fiber (made by the
needle punching method, unit weight: 100 g/m.sup.2) was used as a
green sheet D2.alpha..
[0096] (2) A mixture solution containing 2 parts by mass of a
fluorine group water and oil repellent agent (solid content: 20% by
mass water solution), 20 parts by mass of an acrylic resin emulsion
(solid content: 40% by mass), and 78 parts by mass of water was
used as a coating solution D2.beta..
[0097] (3) Said coating solution D2.beta. was then applied to and
impregnated into said green sheet D2.alpha., the amount of coating
being adjusted to be 20% by mass by a roll coater. A mixture
solution containing 20 parts by mass of a polyester copolymer
(particle size: 20 to 30 .mu.m, melting point: 120.degree. C.), 0.5
parts by mass of an acrylic ester and acrylic acid copolymer resin,
and 79.5 parts by mass of water was prepared, as a hot melt
adhesive, and said mixture solution was then applied to one side of
said green sheet by spray coating, the amount of coating being
adjusted to be 15 g/m.sup.2, following which said green sheet, to
which said mixture solution was applied, was then dried at
150.degree. C. for 4 minutes, to obtain a surface sheet D2.
3. Lamination
[0098] Said surface sheet D2 was then put onto the surface of said
base sheet D1 so as to contact the side of said surface sheet D2 to
which said hot melt adhesive was applied, following which the
resulting laminated sheet was molded by hot pressing at 150.degree.
C. for 40 seconds, to obtain a porous sheet D with a thickness of 5
mm.
[0099] The ventilation resistance of said porous sheet D was 0.5
kPas/m.
[Porous Sheet E]
[0100] A fiber mixture sheet containing 70 parts by mass of a
carbon fiber (fineness: 1.2 dtex, fiber length: 70 mm), and 30
parts by mass of a polypropylene fiber (fineness: 1.5 dtex, fiber
length: 55 mm) was molded by hot pressing at 180.degree. C., to
obtain a porous sheet E with a unit weight of 800 g/m.sup.2, and a
thickness of 2 mm.
[Manufacture of Core Panel]
[Core Panel A]
[0101] Using a thermoplastic resin sheet made of a mixture of
polypropylene/polyethylene/talc=70/10/20 weight ratio and having a
thickness of 0.5 mm, a core panel A having a shape as shown in FIG.
2 was manufactured by the common vacuum forming method.
[0102] Before said vacuum forming, said thermoplastic resin sheet
was not stretched widthwise.
[0103] The size of said core panel A was 40 mm long, 40 mm wide,
and 15 mm in height.
[0104] The number of tubular cells was 484 cells/m.sup.2. The
bottom of each cell was cut out so as to be a bottomless tubular
rectangular cell.
[Core Panel B]
[0105] Using a thermoplastic resin sheet made of a polymer alloy of
an engineering plastic consisting of styrene modified polyphenylene
ether/polyamide/styrene-hydrogenated polyolefin-styrene block
copolymer with a 55/40/5 weight ratio and having a thickness of 0.3
mm, a core panel B having a shape as shown in FIG. 2 was
manufactured by the common vacuum and pressure forming method.
[0106] Before said vacuum and pressure forming, said thermoplastic
resin sheet was stretched widthwise. The degree of stretching was
10% of the original width.
[0107] The size of said core panel B was 40 mm long, 40 mm wide,
and 855 mm in height.
[0108] The number of tubular cells was 484 cells/m.sup.2.
[0109] The bottom of each cell was cut out so as to be a tubular
rectangular cell.
[Core Panel C]
[0110] Using a three layer laminated sheet having a thickness of
1.2 mm as a thermoplastic resin sheet, wherein polypropylene layers
having a thickness of 0.05 mm were attached to the both sides of a
propylene-ethylene copolymer layer to which talc was added in an
amount of 30% by mass, the thickness of said propylene-ethylene
copolymer layer being 1.1 mm, a core panel C having a shape as
shown in FIG. 2 was manufactured by the common vacuum forming
method.
[0111] Before said vacuum forming, said thermoplastic resin sheet
was not stretched widthwise.
[0112] The size of said core panel C was 20 mm long, 20 mm wide,
and 10 mm in height.
[0113] The number of said tubular cells was 1089 cells/m.sup.2. The
bottom of each tubular cell was not cut out so as to be a bottomed
tubular rectangular cell.
[Core Panel D]
[0114] Using a thermoplastic resin sheet having a thickness of 0.6
mm made of a polypropylene to which 15% by mass of a polyammonium
phosphate as a fire retardant agent and 10% by mass of talc, were
added, a core panel D was manufactured by the common vacuum forming
method.
[0115] Before said vacuum forming, said thermoplastic sheet was not
stretched widthwise.
[0116] The size of said core panel D was 150 mm in diameter and 10
mm in height.
[0117] The number of tubular cells was 25 cells/m.sup.2.
[0118] The bottom of each tubular cell was cut out so as to be a
bottomless tubular cell,
[Manufacture of the Shock and Sound Absorbing Member]
[Shock and Sound Absorbing Member A]
[0119] A base panel made of an iron panel having a thickness of 0.2
mm, said porous sheet A, and said core panel A were each molded
into a prescribed shape, and then said core panel A was put onto
said base panel, and further, said porous sheet A was put onto said
core panel A, and these were clipped together, to obtain a shock
and sound absorbing member A.
[Shock and Sound Absorbing Member B]
[0120] A base panel consisting of an article molded by the
injection molding of polypropylene, was prepared, said base panel
having a thickness of 2 mm. Said porous sheet B and said core panel
B were each molded into a prescribed shape, and said core panel B
was then put onto said base panel, then said porous sheet B was put
onto said core panel B, and these were clipped together, to obtain
a shock and sound absorbing member B.
[Shock and Sound Absorbing Member C]
[0121] A base panel consisting of an article molded by the
injection molding of polypropylene was prepared, said base panel
having a thickness of 3 mm. Said porous sheet C and said core panel
D were each molded into a prescribed shape, and said core panel D
was put onto said base panel, and further, said porous sheet C was
put onto said core panel D, and these were clipped together, to
obtain a shock and sound absorbing member C.
[Shock and Sound Absorbing Member D]
[0122] Said porous sheet D and said core panel C were each molded
into a prescribed shape, and the bottoms of the tubular cells were
set to be the base panel, and said porous sheet D was then put onto
said core panel C, and these were clipped together to obtain a
shock and sound absorbing member D.
[Shock and Sound Absorbing Member E]
[0123] Said porous sheet E was prepared as a base panel. Said
porous sheet B and said core panel C were each molded into a
prescribed shape, and said core panel C was then put onto said base
panel, and further, said porous sheet B was put onto said core
panel C, and these were clipped together, to obtain a shock and
sound absorbing member E.
[Material Samples Used in Comparisons]
[Manufacture of the Porous Sheet]
[Porous Sheet F]
[0124] A porous sheet. F was obtained from said porous sheet A,
with the exception that its thickness was set to be 2 mm, and its
unit weight was set to be 200 g/m.sup.2.
[0125] The ventilation resistance of said porous sheet F was 0.05
kPa s/m.
[Porous Sheet G]
[0126] A porous sheet G was obtained by lapping a pair of said
porous sheets F together with a polypropylene film (thickness: 40
.mu.m) placed between them, and the resulting laminated sheet was
hot pressed at 180.degree. C., to obtain a porous sheet G having a
thickness of 2 mm. The ventilation resistance of said porous sheet
G was 6.5 kPa s/m.
[Manufacture of the Shock and Sound Absorbing Member]
[Shock and Sound Absorbing Member F]
[0127] In said shock and sound absorbing member A, said porous
sheet F was used instead of said porous sheet A, to obtain a shock
and sound absorbing member F.
[Shock and Sound Absorbing Member G]
[0128] In said shock and sound absorbing member A, said porous
sheet G was used instead of said porous sheet A, to obtain a shock
and sound absorbing member G.
[Performance Test]
[0129] The performance test was conducted on 5 samples, said shock
and sound absorbing member A to said shock and sound absorbing
member E in EXAMPLES and 2 samples, said shock and sound absorbing
member F and said shock and sound absorbing member G, to evaluate
performance.
[0130] The performance test was conducted in a reverberation room.
Each sample's degree of sound and absorption was measured according
to JIS A 1409. When the measurements were taken, the base panel
side of each shock and sound absorbing member was placed at the
lowermost part of each of said shock and sound absorbing
member.
[0131] The test results are shown by the graphs in FIG. 8.
Referring to the graphs in FIG. 8, each of said shock and sound
absorbing members A to E, has excellent sound absorbing and
insulating properties.
[0132] Shock and sound absorbing member A had an excellent sound
absorbing property for sound in the mid-frequency band (600 to
2500H.sub.2).
[0133] Shock and sound absorbing member B had an excellent sound
absorbing property for sound in the mid-frequency band (600 to
2500H.sub.2). Further, said shock and sound absorbing member B had
an excellent heat resistance and although each tubular cell was
tall as high as 855 mm, as a result of the thermoplastic resin
sheet having been stretched widthwise before vacuum and pressure
forming, the molded article (core panel B) had a nearly uniform
thickness, and was without unevenness as a whole.
[0134] Shock and sound absorbing member C had an excellent sound
absorbing property for sound in the mid-frequency band (600 to
2500H.sub.2) to the high frequency band (3000 to 6000H.sub.2), and
further had excellent flame retardancy.
[0135] Shock and sound absorbing member D had an excellent sound
absorbing property for sound particularly in the high frequency
band (3000 to 6000H.sub.2), and had an advantage of light
weight.
[0136] Shock and sound absorbing member E had an excellent sound
absorbing property for sound in the mid-frequency band (600 to
2500H.sub.2) to the high frequency band (3000 to 6000H.sub.2) and
good flame retardancy. Further, as well as good sound absorption,
the rectification effect of the base material was excellent.
[0137] Shock and sound absorbing member F as COMPARISON had a sound
absorbing property, but only for sound in a partial, particular
mid-frequency band (600 to 2500H.sub.2).
[0138] Shock and sound absorbing member G as COMPARISON had a low
sound absorbing property for any frequency band.
POSSIBILITY OF INDUSTRIAL USE
[0139] Said shock and sound absorbing member of the present
invention has very excellent sound insulating and absorbing
properties, and is useful as a engine under cover or upper cover,
or the like.
* * * * *