Note: Descriptions are shown in the official language in which they were submitted.
` ~073~1L9S
The present invention relates to a light transmissible
high density elastic resin composition which has an excellent
sound-barrier effect and sheets formed therefrom. ~ `
Heretofore, it has been usual to use a lead plate or a
sheet of a mixture of a thermoplastic resin and a powdery metal
having high density such as lead, as a sound-barrier product.
However, such a conventional sound-barrier product is opaque and
when used in a room, it is necessary to provide artificial light ~;
even in the daytime.
The present invention provides a resin composition
having excellent light transmissibility and sound-barrier effect ~
for both aerial sound waves and solid sound waves. ~ .
I According to the present invention there is provided a
¦ light transmissible, high density elastic sound barrier compo-
' sition having a specific gravity of greater than 1.8 which com-
J prises: 100 wt. parts of a thermoplastic resin selected from the
~ group consisting of polyvinyl chloride, vinyl chloride-vinyl
-~.
acetate copolymer, polyvinylidene chloride, polyethylene, poly- ~ `
propylene, polyvinyl acetate, ethylene-vinyl acetate copolymer,
polyester and polyurethane or a mixture of the thermoplastic
resin and a plasticizer and 100 to 500 wt. parts of spherical
lead glass having an average diameter of 40 to 120 ~m and a
refractive index ND of 1.5-2.2.
As used here the term of "light transmissible" include
"semi-transmissible" materials and is not limite~ to transparent
materials.
The thermoplastic resins used in the invention include
polyvinylchloride, a vinyl chloride-vinyl acetate copolymer, ;;
polyvinylidene, chloride, polyethylene, polypropylene, polyvinyl
acetate, an ethylene-vinylacetate copolymer, nylon, a polyester
and a polyurethane. The degree of polymerization of the thermo-
plastic resin is preferably in a range of 1000 - 2500.
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The plasticizers used in the composition of the present
invention include dibutylphthalate, dihexyl phthalate, diethyl-
hexyl phthalate, dioctyl phthalate, diisooctyl phthalate, butyl-
octyl phthalate, dioctyl adipate r diisooctyl adipate, didecyl
adipate, diethylhexyl adipate, diethylhexyl azelate diisooctyl
azelate, tricresyl phosphate, diethyleneglycol dipelargonate, -
and an epoxy type plasticizer.
The plasticizer is added to the resin e.g. polyvinyl
chloride to impart softness thereto. The amount of the plastic-
izer is preferably in a range of from 50 ~ 150 wt. part per 100
wt. parts of the remaining polyvinyl chlorideO
The amount of the lead glass is suitably in a rangeof from 100 - 500 wt. parts to 100 wt. parts of the thermoplastic
resin or a mixture of the thermoplastic resin and the plasticizer,
so as to yield the resin composition having a specific gravity
; of higher than 1.8. When the amount of the lead glass is less
; than 100 wt. parts, the specific gravity of the resin composition
is too low to provide a sufficient sound-barrier effect. When
the amount of the lead glass is greater than 500 wt. par-ts,
physical properties such as a tensile strength of the resin com-
position are disadvantageously low. It is especially preferable
to combine 300 - 400 wt. parts of the lead glass with 100 w~.
parts of the thermoplastic resin or the mixture of the thermo-
plastic resin and the plasticizer.
The refractive index of the lead glass is preferably
near that of the thermoplastic resin. The difference of refrac-
tive index of the lead glass to that of the resin composition is
preferably in a range of from 0 - 0.8 ~ND). The refractive
index of the thermoplastic resin is usually in a range of from
1.4 - 1.6 (ND). Accordingly, it is desirable to be from 1.5 -
2.2 (ND) especially from 1.5 - 1.8 (ND) of the refractive index.
When a glass having super high refractive index, e.g. greater
.~ .
1~73~5
than 2.2, is used, the central refractive luminance of the
powder glass is too high to aecrease light transmittance.
The lead glass used in the invention is spherical
(beads), because the spherical particles of the glass impart a
lens effect to increase light transmittance The average dia-
meter of the lead glass is in the range 40 -- 120 ~.
When the average diameter of the particles is less
than 40 ~l, the light transmittance is reduced because of diffuse
reflection. When the average diameter of the particles :LS '
higher than 120 ~, -the physical properties such as tensile
strength of the resin composition are reduced. The average ;~
diameter of the powdery glass is thus from 40 - 120 ~. The
specific gravity of the lead glass is usually higher than 2.4,
' ' ':
preferably higher than 3.0, so as to increase the density of
the resin composition and to impart the sound-barrier effect,
' and it is selected depending upon a ratio of the lead glass.
It is possible to add a transparent pigment, a dye,
' a stabilizer, a lubricant, parting agent, etc. to the resin
composltion of the invention, if desirable. It is preferable
to select a stabilizer having transparency such as epoxy veget~
able oils, Cd-Ba-Zn type organic composites and organo-tin com-
pounds.
A sheet of the resin composition of the invention can
be prepared by kneading to disperse the powdery glass by means
of an extruder, a hot-kneader or a hot-roller mill and then,
pelletizing it and sheeting by means of a calender roller and
an extruder. The sheet of the resin composition can be also
prepared by means of hot-roller mill to directly form the sheet
by kneading to disperse the lead glass and extruding to form
the sheet.
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The resulting sheet may be used as a light transmiss-
ible sound-barrier sheet. The sheet made of the resin compos~
ition of the invention preferably has a thickness of 0.4 - 2 mm,
and a specific gravity of more than 1.8, a total light transmit-
tance of more than 10%, a tensile strength of more than 30 Kg/cm
and is useable as a sound-barrier product. It is preferable to
reinforce the sheet of the resin composition of the present
invention with a split film nonwoven fabric which is prepared by
stretching a film of a ~hermoplastic resin such as polyethylene
or polypropylene to form split fibers with fine cracks having
lengths of 0.1 - 0.3 mm to the stretching direction and lamin-
ating the sheets in transverse and longitudinal directions,
under hot-melt bonding.
The sheet of the resin composition of the invention
can suitably be used as a sound-barrier curtain, accordion type
door in a sickroom and a consultation room in a hospital, a
lecture room in school, a living room and a workroom of a factory.
The sheet can be also used as a X-ray shield board. The present
invention will be further illustrated by the following Examples
in which the term of "part" designates "part by weight".
EXAMPLE 1:
lO0 parts of polyvinyl chloride (Degree of polymeriz-
ation lO00) was admixed with 30 parts of plasticizer of dioctyl
phthalate, 20 parts of dioctyl adipate, a small amount of epoxy
vegetable oil (supplied under the trademark Eposizer W-lO0-EL
manufactured by Dainippon Ink Chemical I~abushike Kaisha) and a
Cd-Ba-Zn type organic stabilizer.
The mixture was kneaded at 100C for l hour. The mix-
ture was mixed with 450 parts of glass beads of specific gravity
of 4.8; refrac~ive index of 1.8; and average diameter of 70
and the mixture was kneaded in a continuous kneader at 160C
for about 2 minutes, was extruded through a die opening having
~ 3~9~i ;
a diameter of 3mm and was cut to form pellets. The pellets
were kneaded by a mixing roller mill at 160C to extrude it
as a sheet having a thickness of 1 mm. The glass beads used
were those supplied under the trademark U~3-46J manufactured by
Union Glass Co. and will be referred to hereinafter as glass
' beads A.
,.~ ,.
EXAMPLES 2 - 7:
The pr~cess of Example 1 was repeated except using the
~ .
components shown in the following Table 1 to prepare each high ~--
density sheet.
The properties of the resulting sheets are shown in
Table 1.
, '
., ~
~ 20
; 3Q
1~73~.9S ~Z -
o o ~ ccZZ ~' ~1 ,'
_ . - - '- -1 " ' '
~ Z o 1~ o ..
t,g O O O U~ O ~Z ~ ~ ~ .
.' _ . - .
o o o .,. o ~ o ~Z o t~ ~.
. ' . O ~ ~ t ~Z1- ~ ~ '
_ ' : ~
Z, : ~ ~.Z . , .
;l d' O o o u~) ~I ~) O O
' _ _
`, ~,Z Oo o ~n cZ ~ , ,~ ~ ,.
: .
.~ _ . _ ''~'
O O O1~ 0 ~ (~3 0 Lr,t C~ .: .
~ ~ Z I~ 1 . ' ~
11
~ _ Lt~ '~"
'~ O ~~ 1 ~ ~Z ~ ~10 Z ~_ ~
~ _ _ ~
~ ~ _ ~ ,_ _ _ ~ ~ :'
,ZZ ~- LtZ ~Z ~C ~ o
'' o ~ ~Z ~ m ~ ~ ~ ~ -:
~,tZ O ~ ' ~ ~ ~ ~ ~~ ~ \ o\ ~ O
g~ ~ ~, a 4 P~ a
-- 6 -- . ZZ
1(~73~5
¦ Note:
! *l) UB-24H a -trademark of Union Glass Co. (specific gravity
¦ 4.8; refractive index 2.2; average diameter 50 ~)
! *2) UB-78H a trademark of Union Glass Co. ~specific gravity
4.g; refractive index 2.2; average diameter 110 ~
*3) Amorphous glass (specific gravity 4.0; refractive index
2.0; average diameter 90 ~)
.*4) Japanese Industrial Standard K-6911-5.?8
*5) Japanese Industrial Standard K-6723.
*6) ASTM -D-638-68 '
*7) Hitachi 323 (a trademark) type automatic spectrophoto-
:~.
~ meter (340 - 700 m~) ,
" ~
*8) Japanese Industrial Standard C-1502 -
; EXAMPLE 8: '~
100 ~arts of an ethylene-vinylacetate copolymer (sup-
plied under the trademark EVATATE K-2010 manufactured by Sumitomo
,' Kagaku K.K.) was admixed with 0.5 parts of zinc stearate.
~! The mixture was mixed with 500 parts of Glass beads A
in a continuous kneader at 100 - 110C for a retension time greater
than 2 minutes, was extruded through a die opening having a dia-
meter of 3mm and was cut to form pellets. The pellets were
kneaded in a mixing roller mill at 100 - 110C to extrude it as `
a sheet having a thickness of 1 mm. The sheet had a specific
gravity of 2.6; a tensile strength of 37 Kg/cm2; an elongation of
817%; a total light transmission of 14% and a sound wave trans-
~3 mission loss (1000 Hz) of 18.
~;3 EXAMPLE 9: f
100 parts of a vinylchloride-ethylene-vinylacetate co- ;
polymer (supplied under the trademark SUMIGRAFT GF: Sumitomo !
Kagaku K.K.) was admixed with 0.5 parts of zinc stearate.
The mixture was mixed with 500 parts of Glass beads A
in a continuous kneader at 90 - 100C for a retension time
D73195
.;. ~ ,:
,
greater than 2 minutes, was extruded through a die opening hav~
ing a diameter of 3 mm and was cut to form pellets. The pellets
were kneaded in a mixing roller mill at 90 - 100C to extrude
it as a sheet having a ~hickness of 1 mm. The sheet had a
specific gravity of 3.0; a tensile s~rength of 32 Kg/cm , an
elongation of 307%; a total light transmission of 10% and a
sound wave transmission loss (100 Hz) of 20.
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