U.S. patent application number 11/991554 was filed with the patent office on 2009-11-05 for sound insulating material.
Invention is credited to Armand Alphons Duijsens, Nobuhiko Inui, Eduard Karel Offermanns, Laurens Petrus Vogels, Joji Yamada.
Application Number | 20090272932 11/991554 |
Document ID | / |
Family ID | 37888725 |
Filed Date | 2009-11-05 |
United States Patent
Application |
20090272932 |
Kind Code |
A1 |
Inui; Nobuhiko ; et
al. |
November 5, 2009 |
Sound Insulating Material
Abstract
The present invention provides a sound insulating material
excellent in sound insulation property and moldability. The sound
insulating material of the present invention contains an inorganic
compound in a thermoplastic resin foam and is characterized by
containing the inorganic compound in an amount of from 30 to 300
parts by weight per 100 parts by weight of the thermoplastic resin
constituting the thermoplastic resin foam. Therefore, it has
excellent sound insulation property and moldability. In addition,
because the sound insulating material can be formed accurately into
a shape in conformity with the shape of a sound-insulated member to
which sound insulation treatment is intended to be applied using a
known molding method, it can be adhered stably to, for example,
automobile floor materials and sound-insulated members such as
partition walls separating an engine room and the vehicle interior,
almost without forming any gap between the sound insulating
material and the sound-insulated member and it is possible to
subject the sound-insulated member to sound insulation treatment
certainly.
Inventors: |
Inui; Nobuhiko; (Saitama,
JP) ; Yamada; Joji; (Saitama, JP) ;
Offermanns; Eduard Karel; (Kerkrade, NL) ; Duijsens;
Armand Alphons; (Geulle, NL) ; Vogels; Laurens
Petrus; (Budel, NL) |
Correspondence
Address: |
WENDEROTH, LIND & PONACK, L.L.P.
1030 15th Street, N.W.,, Suite 400 East
Washington
DC
20005-1503
US
|
Family ID: |
37888725 |
Appl. No.: |
11/991554 |
Filed: |
September 5, 2006 |
PCT Filed: |
September 5, 2006 |
PCT NO: |
PCT/JP2006/317566 |
371 Date: |
March 6, 2008 |
Current U.S.
Class: |
252/62 |
Current CPC
Class: |
C08J 2323/02 20130101;
C04B 26/02 20130101; C04B 26/02 20130101; C08J 9/0061 20130101;
C08J 2300/22 20130101; C08J 2431/00 20130101; G10K 11/162 20130101;
C04B 2111/52 20130101; C08J 9/0066 20130101; C04B 38/02 20130101;
C04B 14/368 20130101; C08J 9/103 20130101 |
Class at
Publication: |
252/62 |
International
Class: |
E04B 1/74 20060101
E04B001/74 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 8, 2005 |
JP |
2005-261283 |
Claims
1. A sound insulating material comprising a thermoplastic resin
foam and an inorganic compound contained in the thermoplastic resin
foam in an amount of from 30 to 300 parts by weight per 100 parts
by weight of the thermoplastic resin constituting the thermoplastic
resin foam.
2. The sound insulating material according to claim 1, wherein the
thermoplastic resin constituting the thermoplastic resin foam is a
polyolefin-based resin.
3. The sound insulating material according to claim 1, wherein the
inorganic compound is a metal salt of an inorganic acid.
4. The sound insulating material according to claim 1, wherein the
sound insulating material has an apparent density of from 0.1 to
0.8 g/cm.sup.3.
5. The sound insulating material according to claim 1, wherein the
inorganic compound is contained in an amount of from 75 to 250
parts by weight per 100 parts by weight of the thermoplastic resin
constituting the thermoplastic resin foam.
6. The sound insulating material according to claim 1, wherein the
inorganic compound is barium sulfate.
7. The sound insulating material according to claim 1, wherein the
resin magnification ratio of the thermoplastic resin constituting
the thermoplastic resin foam is 300% or more.
Description
TECHNICAL FIELD
[0001] The present invention relates to sound insulating materials
excellent in sound insulation property and moldability.
BACKGROUND ART
[0002] Conventionally, various types of sound insulating materials
have been commonly used in rides such as elevators as well as
vehicles, e.g. automobiles and trains. Especially, in automobile
applications, the entry of engine noises into the vehicle interior
is a factor in deterioration of the interior sound environment. For
this reason, sound insulating materials are used in engines, floor
sheets, trunks and the like.
[0003] As such a sound insulating material, Patent Document 1
proposes a sound shielding sheet having an elastic modulus at
20.degree. C. of 5.times.10.sup.7 Pa or less prepared by kneading a
binder component containing 90% by weight or more of a rubber
component, a filler material component and additives, followed by
rolling.
[0004] This sound shielding sheet contains the filler material
component in the binder component in order to possess sound
shielding property by increasing the density and therefore it has a
high specific gravity. As an adverse result, the sound shielding
sheet is so hard that it is difficult to cut and it is poor in
moldability in bending or the like.
[0005] Moreover, the sound shielding sheet is also poor in
extensibility and therefore an attempt to form the sound shielding
sheet with a mold has resulted in failure in forming it into a
formed article having a desired shape due to generation of cracks
in the sheet or breakage of the sheet.
[0006] Therefore, an attempt to adhere a sound shielding sheet to a
complexly-shaped vibrating metal panel such as an automotive floor
steel panel after forming the sheet into a shape in conformity with
the shape of the vibrating metal panel will result in generation of
a gap between the sound shielding sheet and the vibrating metal
panel because it is impossible to form the sound shielding sheet
accurately into the shape in conformity with the shape of the
vibrating metal panel. This has adversely required an additional
work of filling the gap.
[0007] Patent Document 1: JP 6-301385 A
DISCLOSURE OF THE INVENTION
Problem to be Solved by the Invention
[0008] The present invention provides a sound insulating material
excellent in sound insulation property and moldability.
Means for Solving the Problem
[0009] The sound insulating material of the present invention is
characterized by comprising a thermoplastic resin foam and an
inorganic compound contained in the thermoplastic resin foam in an
amount of from 30 to 300 parts by weight per 100 parts by weight of
the thermoplastic resin forming the thermoplastic resin foam.
[0010] That is, the sound insulating material of the present
invention contains an inorganic compound in a thermoplastic resin
foam and is characterized by containing the inorganic compound in
an amount of from 30 to 300 parts by weight per 100 parts by weight
of the thermoplastic resin forming the thermoplastic resin
foam.
[0011] The thermoplastic resin constituting the thermoplastic resin
foam is not particularly restricted, and examples thereof include
organic materials such as polyolefin-based resins, for example,
polyethylene-based resins, e.g. high density polyethylene, medium
density polyethylene, low density polyethylene, linear low density
polyethylene and ethylene-vinyl acetate copolymers,
polypropylene-based resins, e.g. propylene homopolymers and
copolymers of propylene and other olefins; polystyrene-based
resins; polyester-based resins; polyamide-based resins;
polyamide-based resins; and petroleum resins. Polyolefin-based
resins are preferred, and use of a polyethylene-based resin and an
ethylene-vinyl acetate copolymer in combination is more preferred
because the sound insulating material excels in rigidity and
therefore it has good workability since it hardly deflects or warps
during handling.
[0012] By causing the thermoplastic resin foam to contain the
inorganic compound in the predetermined amount, the sound
insulating material is formed. Examples of the inorganic compound
include metal hydroxides such as aluminum hydroxide and magnesium
hydroxide as well as metal salts of inorganic acids, such as barium
sulfate and magnesium sulfate. Since a sound insulating material is
heated during molding, metal salts of inorganic acids, which are
never decomposed by the application of heat, are preferred and
barium sulfate is more preferred.
[0013] The content of the inorganic compound in the sound
insulating material is limited to from 30 to 300 parts by weight,
and preferably is from 75 to 250 parts by weight, per 100 parts by
weight of the thermoplastic resin forming the thermoplastic resin
foam because if the content is too small, the sound insulation
property of the sound insulating material will be damaged, and if
it is too large, the moldability of the sound insulating material
will be damaged.
[0014] As described above, the sound insulating material of the
present invention exerts excellent sound insulation performance due
to filling of such predetermined amount of an inorganic compound in
a thermoplastic resin foam. If a thermoplastic resin is filled in a
high concentration with an inorganic filler, especially an
inorganic compound having a great specific gravity like barium
sulfate, generally, the moldability of the thermoplastic resin will
be damaged due to decrease in extensibility thereof and therefore
it will become difficult to apply molding methods like vacuum
molding.
[0015] Then, in the sound insulating material of the present
invention, in order to compensate the decrease in extensibility of
the thermoplastic resin due to the inclusion of the inorganic
compound, the thermoplastic resin is foamed to be in the form of a
thermoplastic resin foam and the inorganic compound is contained in
the thermoplastic resin foam. By forming a thermoplastic resin foam
by foaming a thermoplastic resin in such a manner, it is possible
to increase the elongation at breakage of the thermoplastic resin
in its extension, and as a result, it is possible to improve the
moldability of the thermoplastic resin foam, i.e., the sound
insulating material, and it is possible to mold the sound
insulating material accurately into a desired shape using a known
molding method, such as vacuum molding.
[0016] In other words, because the sound insulating material of the
present invention has been caused to have an improved extensibility
by forming a thermoplastic resin foam by foaming a thermoplastic
resin, it is possible to fill the thermoplastic resin foam with an
inorganic compound in a high concentration and, as a result, the
sound insulating material of the present invention excels in
moldability as well as in sound insulation property.
[0017] The apparent density of the thermoplastic resin foam
containing an inorganic compound, i.e., the sound insulating
material is preferably from 0.1 to 0.8 g/cm.sup.3, and is more
preferably from 0.25 to 0.7 g/cm.sup.3 because if it is too small,
the sound insulation property of the sound insulating material may
be damaged and if it is too large, the moldability of the sound
insulating material may be damaged. Here, the apparent density of a
sound insulating material is a value measured in accordance with
JIS Z6767.
[0018] The resin magnification ratio of the thermoplastic resin
constituting a thermoplastic resin foam is preferably 300% or more,
and more preferably 500% or more because if it is too small, the
moldability of a sound insulating material may be damaged due to
decrease in the extensibility of the thermoplastic resin
constituting the thermoplastic resin foam. The resin magnification
ratio is preferably 1500% or less, and more preferably 1000% or
less because if it is too large, a tear or crack may be formed in a
sound insulating material during its molding.
[0019] The resin magnification ratio of the thermoplastic resin
constituting a thermoplastic resin foam is a measure indicating the
volumetric expansion ratio before and after the foaming of the
thermoplastic resin itself, and specifically, is calculated from
the formula 1 shown below. The density of the inorganic compound is
represented by A g/cm.sup.3 and the density of the thermoplastic
resin constituting the thermoplastic resin foam is represented by B
g/cm.sup.3. The weight of the inorganic compound contained in the
thermoplastic resin foam is represented by X g and the weight of
the thermoplastic resin is represented by Y g. The apparent density
of the entire thermoplastic resin foam containing an inorganic
compound is set forth as C g/cm.sup.3. When the thermoplastic resin
constituting the thermoplastic resin foam is a mixture of two or
more kinds of thermoplastic resins, the density of the
thermoplastic resin is the density of the mixture of the
thermoplastic resins.
[ Numerical Formula 1 ] Resin magnification ratio ( % ) = ( X + Y C
- X A ) ( Y B ) .times. 100 Formula 1 ##EQU00001##
[0020] The thickness of the sound insulating material is preferably
from 2 to 6 mm because if it is too small, the sound insulation
property of the sound insulating material may be damaged or the
mechanical strength of the sound insulating material may be
damaged, while if it is too large, the moldability of the sound
insulating material may be damaged. The sound shielding property of
the sound insulating material is preferably 5 dB or more, and more
preferably 10 dB or more.
[0021] Next, the method for producing the sound insulating material
of the present invention is described. The method for producing the
sound insulating material of the present invention is not
particularly restricted and may be, for example, (1) a method of
producing a sound insulating material by supplying a foamable resin
composition which comprises a thermoplastic resin, an inorganic
compound and a pyrolysis-type foaming agent into a versatile
stirring apparatus, such as a Labo Plastomill, followed by
melt-kneading, then forming a foamable resin sheet by a versatile
molding method, such as press molding, followed by optionally
crosslinking this foamable resin sheet by application of ionizing
radiations, such as electron beam, .alpha.-ray and .beta.-ray, and
then foaming the foamable resin sheet by heating it to a
temperature not lower than the decomposition temperature of the
pyrolysis-type foaming agent; or (2) a method of producing a sound
insulating material continuously by supplying a foamable resin
composition which comprises a thermoplastic resin, an inorganic
compound and a pyrolysis-type foaming agent into an extruder,
followed by melt-kneading, then extruding a foamable resin sheet
continuously from the extruder, followed by optionally crosslinking
this foamable resin sheet by application of ionizing radiations,
such as electron beam, .alpha.-ray and .beta.-ray, and then foaming
the foamable resin sheet by heating it to a temperature not lower
than the decomposition temperature of the pyrolysis-type foaming
agent.
[0022] The pyrolysis-type foaming agent is not particularly
restricted if it is one having heretofore been used for the
production of foamed products. Examples thereof include
azodicarbonamide, benzenesulfonyl hydrazide,
dinitrosopentamethylenetetramine, toluenesulfonyl hydrazide, and
4,4-oxybis (benzenesulfonyl hydrazide). These may be used singly or
in combination of two or more thereof.
[0023] The resulting sound insulating material is molded into a
shape in conformity with the shape of a member to which sound
insulation treatment is intended to be applied, which may be
referred to as a "sound-insulated member", such as automotive floor
steel panels, and then is used by being adhered to the
sound-insulated member with an adhesive or the like. As the molding
method for molding a sound insulating material, a conventionally
known molding method may be used. Examples of such molding method
include vacuum molding and pneumatic molding.
[0024] In this connection, since the sound insulating material has
been formed accurately in conformity with the shape of the
sound-insulated member, it is possible to adhere the sound
insulating material to the sound-insulated member forming almost no
gap between the sound insulating material and the sound-insulated
member and therefore sound insulation treatment can be performed
easily.
EFFECT OF THE INVENTION
[0025] The sound insulating material of the present invention has
excellent sound insulating properties, especially sound shielding
property, and also is excellent in moldability because it comprises
a thermoplastic resin foam and an inorganic compound contained in
the thermoplastic resin foam in an amount of from 30 to 300 parts
by weight per 100 parts by weight of the thermoplastic resin
constituting the thermoplastic resin foam.
[0026] Therefore, the sound insulating material of the present
invention can be molded accurately into a shape in conformity with
the shape of a sound-insulated member to which sound insulation
treatment is intended to be applied using a known molding method.
Accordingly, it can be adhered stably to, for example, automobile
floor materials and sound-insulated members such as partition walls
separating an engine room and the vehicle interior, almost without
forming any gap between the sound insulating material and the
sound-insulated member and it is possible to subject the
sound-insulated member to sound insulation treatment certainly.
[0027] Moreover, when the thermoplastic resin constituting the
thermoplastic resin foamed sheet is a polyolefin-based resin, the
sound insulating material of the present invention excels in
rigidity and therefore it has good workability since it hardly
deflects or warps during handling of the sound insulating
material.
[0028] Furthermore, in the sound insulating material of the present
invention, when the inorganic compound is a metal salt of an
inorganic acid, it remains stably in the thermoplastic resin foam
despite the heat applied during the molding of the sound insulating
material and it is possible to mold the sound insulating material
into a desired shape without damaging the sound insulation
performance thereof.
[0029] The sound insulating material of the present invention has
more improved sound insulation property and moldability when it has
an apparent density of from 0.1 to 0.8 g/cm.sup.3.
BRIEF DESCRIPTION OF THE DRAWING
[0030] FIG. 1 A schematic sectional view illustrating the procedure
of measuring the moldability of a sound insulating material.
DESCRIPTION OF THE REFERENTIAL NUMERALS
[0031] 1 Female mold [0032] 2 Molded article [0033] 21 Bottom
[0034] 22 Peripheral wall
BEST MODE FOR CARRYING OUT THE INVENTION
Example 1
[0035] A foamable resin composition composed of 65 parts by weight
of low density polyethylene (commercial name "LE520" produced by
Sumitomo Mitsui Polyolefin Co.), 35 parts by weight of an
ethylene-vinyl acetate copolymer (commercial name "EVAFLEX EV460"
produced by DuPont-Mitsui Polychemicals, Co., Ltd.; vinyl acetate
content: 19% by weight), 150 parts by weight of barium sulfate
(commercial name "W-1" produced by Takehara Kagaku Kogyo Co.,
Ltd.), 4 parts by weight of azodicarbonamide (commercial name
"Uniform AZ SO-40" produced by Otsuka Chemical Co., Ltd.) and 1
part by weight of zinc stearate (commercial name "SZ-2000" produced
by Sakai Chemical Industry Co., Ltd.) as a foaming aid was fed into
a Labo Plastomill and was kneaded at 110.degree. C. for 15 min to
mix uniformly. The foamable resin composition was press molded at
110.degree. C. to yield a foamable resin sheet having a thickness
of 2.5 mm.
[0036] The foamable resin sheet was crosslinked by irradiating the
foamable resin sheet with 2.0 Mrad electron beam at a condition of
800 KV. This foamable resin sheet was supplied into an oven, and
the foamable resin sheet was left at rest at 240.degree. C. for 80
seconds to foam. Thus, a sound insulating material was obtained in
which barium sulfate was contained in a foamed sheet made of a
polyolefin-based resin composed of low density polyethylene and an
ethylene-vinyl acetate copolymer. The sound insulating material
obtained had an apparent density of 0.33 g/cm.sup.3 and a thickness
of 3.7 mm. The resin magnification ratio of the polyolefin-based
resin constituting the thermoplastic resin foamed sheet was 650.4%.
The polyolefin-based resin composed of the low density polyethylene
and the ethylene-vinyl acetate copolymer had a density of 0.9
g/cm.sup.3 and the barium sulfate had a density of 4.3
g/cm.sup.3.
Example 2
[0037] A sound insulating material was obtained in the same manner
as in Example 1 except for changing the amount of barium sulfate to
100 parts by weight instead of 150 parts by weight, the amount of
azodicarbonamide to 3 parts by weight instead of 4 parts by weight,
and the amount of zinc stearate to 0.8 parts by weight instead of 1
part by weight. The sound insulating material obtained had an
apparent density of 0.31 g/cm.sup.3 and a thickness of 3.6 mm. The
resin magnification ratio of the polyolefin-based resin
constituting the thermoplastic resin foamed sheet was 559.7%.
Example 3
[0038] A sound insulating material was obtained in the same manner
as in Example 1 except for changing the amount of barium sulfate to
50 parts by weight instead of 150 parts by weight, the amount of
azodicarbonamide to 2 parts by weight instead of 4 parts by weight,
and the amount of zinc stearate to 0.6 parts by weight instead of 1
part by weight. The sound insulating material obtained had an
apparent density of 0.32 g/cm.sup.3 and a thickness of 3.7 mm. The
resin magnification ratio of the polyolefin-based resin
constituting the thermoplastic resin foamed sheet was 411.4%.
Example 4
[0039] A sound insulating material was obtained in the same manner
as in Example 1 except for changing the amount of barium sulfate to
50 parts by weight instead of 150 parts by weight and the thickness
of the foamable resin sheet to 2.0 mm instead of 2.5 mm. The sound
insulating material obtained had an apparent density of 0.16
g/cm.sup.3 and a thickness of 3.7 mm. The resin magnification ratio
of the polyolefin-based resin constituting the thermoplastic resin
foamed sheet was 833.3%.
Comparative Example 1
[0040] A sound insulating material was obtained in the same manner
as in Example 1 except for using no barium sulfate and changing the
amount of azodicarbonamide to 1.4 parts by weight instead of 4
parts by weight, and the amount of zinc stearate to 0.4 parts by
weight instead of 1 part by weight. The sound insulating material
obtained had an apparent density of 0.40 g/cm.sup.3 and a thickness
of 3.7 mm. The resin magnification ratio of the polyolefin-based
resin constituting the thermoplastic resin foamed sheet was
225.0%.
Comparative Example 2
[0041] A sound insulating material was obtained in the same manner
as in Example 1 except for using no barium sulfate and changing the
thickness of the foamable resin sheet to 2.0 mm instead of 2.5 mm.
The sound insulating material obtained had an apparent density of
0.11 g/cm.sup.3 and a thickness of 3.8 mm. The resin magnification
ratio of the polyolefin-based resin constituting the thermoplastic
resin foamed sheet was 818.2%.
Comparative Example 3
[0042] A sound insulating material was obtained in the same manner
as in Example 1 except for changing the amount of barium sulfate to
350 parts by weight instead of 150 parts by weight, the amount of
azodicarbonamide to 6 parts by weight instead of 4 parts by weight,
the amount of zinc stearate to 1.3 parts by weight instead of 1
part by weight and the thickness of the foamable resin sheet to 2.0
mm instead of 2.5 mm. The sound insulating material obtained had an
apparent density of 0.61 g/cm.sup.3 and a thickness of 3.6 mm. The
resin magnification ratio of the polyolefin-based resin
constituting the thermoplastic resin foamed sheet was 590.7%.
Comparative Example 4
[0043] An ethylene-propylene-diene rubber (EPDM) sheet (apparent
density: 2.4 g/cm.sup.3, thickness: 1.7 mm) was used as a sound
insulating material.
[0044] The moldability and sound insulation property of the sound
insulating materials obtained were measured in the procedures given
below and the results are shown in Table 1.
[0045] (Moldability)
[0046] A sound insulating material was heated using a far-infrared
heater so that the temperature of both surfaces of the sound
insulating material would be 140.degree. C. Next, a closed-end
cylindrical female mold 1 shown in FIG. 1 was prepared. The sound
insulating material was vacuum molded with the female mold 1 and as
a result a closed-end cylindrical molded article 2 was obtained
which had a flat circular bottom 21 and a cylindrical peripheral
wall 22 extending perpendicularly from the periphery of the bottom
21. In the vacuum molding of the sound insulating material, the
sound insulating material was vacuum molded as deep as possible
while satisfying three conditions, namely, that the thickness of
the peripheral wall 22 of the molded article 2 is uniform, that
neither cracks nor holes are formed in the bottom 21, and that the
thickness of the bottom 21 is almost equal to the thickness of the
peripheral wall 22.
[0047] A vacuum molding maximum draw ratio (H/D) was calculated
from the diameter D of the outer bottom of the molded article and
the depth H of the sound insulating material vacuum sucked in the
female mold 1, on the basis of the formula 2 given below. The ratio
was used as a measure of the moldability. The greater the vacuum
molding maximum draw ratio, the better the moldability of the sound
insulating material.
Vacuum molding maximum draw ratio(H/D)=depth H/diameter D Formula
2
[0048] In Examples 1 to 3, the vacuum molding maximum draw ratios
were 0.8 or more, and each sound insulating material had excellent
moldability. In Comparative Example 1, the vacuum molding maximum
draw ratio was 0.6. At such a level of moldability, it is not
possible to mold a sound insulating material accurately into a
shape in conformity with the shape of a mold. The sound insulating
material of Comparative Example 3 had poor moldability. It was
almost impossible to vacuum mold the sound insulating material due
to immediate formation of a hole in the bottom. The sound
insulating material of Comparative Example 4 had poor moldability.
It was impossible to vacuum mold the sound insulating material due
to immediate formation of a hole in the bottom.
(Sound Insulation Property)
[0049] The sound shielding property of a sound insulating material
was measured in accordance with JIS A1416, and it was used as a
measure of the sound insulation property. In the specific
procedure, a sound insulating material was mounted into an opening
for mounting a sound insulating material therein provided in a
partition door between a sound generating room and a reverberation
room, the opening being in a square form 600 mm on each side. Thus,
the opening was closed completely. Then, a sound of 90 dB was
generated from the sound source in the sound generating room, and
the loudness level A was measured in the reverberation room using a
noise level meter (commercial name "Precise Noise Level Meter
NA-27" produced by RION Co., Ltd.).
[0050] Next, in a state where the opening was completely open with
no sound insulating material mounted in the opening for mounting a
sound insulating material, the loudness level B was measured in the
same way as mentioned above. The sound shielding property was
calculated based on the following formula 3:
Sound shielding property(dB)=(loudness level B)-(loudness level A)
Formula 3
TABLE-US-00001 TABLE 1 Comparative Comparative Comparative
Comparative Example 1 Example 2 Example 3 Example 4 Example 1
Example 2 Example 3 Example 4 Foamable Low density polyethlene 65
65 65 65 65 65 65 -- resin Ethylene-vinyl acetate 35 35 35 35 35 35
35 -- composition copolymer (parts by weight) Barium sulfate 150
100 50 50 -- -- 350 -- Azodicarbonamide 4 3 2 4 1.4 4 6 -- Zinc
stearate 1 0.8 0.6 1 0.4 1 1.3 -- Sound Apparent density
(g/cm.sup.3) 0.33 0.31 0.32 0.16 0.40 0.11 0.61 2.40 insulating
Thickness (mm) 3.7 3.6 3.7 3.7 3.7 3.8 3.6 1.7 material Resin
magnification ratio 650.4 559.7 411.4 833.3 225.0 818.2 590.7 --
(%) Vacuum molding 0.90 0.90 0.92 0.82 0.60 0.80 Failed in Failed
in maximum draw ratio molding molding (H/D) Sound insulation 10.4
10.2 10.2 5.3 10 3.7 12.0 11.5 property (dB)
INDUSTRIAL APPLICABILITY
[0051] The sound insulating material of the present invention can
be applied to sound-insulated members having various shapes because
it has excellent sound insulation property and excellent
moldability. It therefore can be used in wide variety of
applications such as automobile applications, railway applications
and building applications.
* * * * *