Note: Descriptions are shown in the official language in which they were submitted.
W095/29135 2 1 6 5 0 8 1 PCT~95/01414
~a~-MAD~ VITREOU~ F~R~ ~nn~.
The pre ent invention relates to man-made vitreous
fibre (MMVF) wool cont~i n~ ng iron and a relatively high
amount of ~1k~ earth metals, and a low amount of ~1kA1i
metals, ~o~vel~ionally known as stone, slag or basalt wool.
Various types of NMV fibres are known.
It is known, in the manufacture of traditional glass
fibres, to include in the glass melt compon~nts which
provide boron oxide (borate). This can improve the glass
and the glass melt. However, borate _o~ n;ng raw
materials are ~Yrç~ive and are normally not added at all
if possible, esrec;~lly when the product contains iron and
has low alkali and high AlkAline earth content, as in
con~entional rock, stone and slag melts.
Glass wool products ~ l y have a relatively high
content of ~lk~l ~ metal (often above 13% Na2O + KzO). In
this specification all analyses are expressed by weight of
total composition measured as oYi~PC- Glass filament and
glass wool are ll~ lly free of iron but often also contain
boron. Typically they contain less than 7% Al203. ~U_v~L
E-Glass is a filamentary or other no~l wool product and can
have high aluminium and low or zero ~ 1 t metal. For
instance JP-A-50090719 describes an E-Glass cont~;ning 15-
16% Al203, 9.5-10.5% B2O3 and 5% PzO5~ It is free of iron
and sodium.
Glass fibres are described in EP-A-9418 which can have
a wide range of optionAl components ~nGl~ n~ inter alia,
iron, boron and rh~sr~ous. None of the exemplified
compositions contain both boron and rhOsrhQrous and they
all have above 13% Al~Al~ metal oxide.
W093/07741 describes fibres contA;n;~g 0 to 4% P205,
above 13% Na2O, and up to 8% Al203 for use in horticulture.
B203 can be ~ t but the total amount of impurities
(including any B203 which is included) must be not above 1~.
Glass wool i8 described in EP-A-412878 which has high
A~ met_l content (above 13%) and which contains borate.
It i~ free of iron. Ph~rho~ous is an optional component.
CONFIRMA77ON COPY
Wo95/29135 2 1 6 5 0 8 1 PCT~P9S/01414
It is included allegedly to improve solubility of the
fi~res.
We are co~rned with improving the solubility of the
fibres in those wools generally referred to as rock, stone,
slag or basalt w0018 and which typically contain ~ron, a
low amount of aluminium (below 10%), a low amount of AlkAl;
metal (below 7) and a significant amount of ~1k~l;ne earth
metal (above 12%).
It has been ~r 0~ that it would be desirable to
provide such wools in which the MMV fibres are soluble in
a physiological medium, in particular lung fluid.
It is known that the composition of a fibre can
significantly affect its solubility. For instance, it is
illustrated in W087/05007 that fibres having a low alumina
lS content, in particular alumina below 10% by weight of
composition, have im~o~ed solubility in a physiological
environment. It i8 ~lso known that inclusion of pho~rhorus
can improve solubility in the physiological medium. This
has been illustrated in the case of stone wool fibres in
for instance EP-A-459,897. This discloses stone wool
fibres which comprise 1 to 10% of phosphorus as P20s. This
component îs said to provide solubility in the
physiological medium. It can be ~ssumed that increasing
the amount of ~hG~l.orous within this range increases
solubility.
During the manufacture of NNVF wool the components
which are to form the fibres are melted in a furnace, such
as an electric, ~haft, tank or cupola furnace. This
pro~n~efi a melt which ~ay then be fiberised. The melt
~ ly has a melting point of around 1,400 to 1,600C and
is thus heated to above this temperature in the furnace.
It has been found that the inclusion o~ significant amounts
of phosphorous in the melt can lead to some problems. For
instance ~ho~r~rus may volatilj~e in the furnace, 1~A~
to difficulties of col-~-olling the composition. In
par~ 5--1 Ar increasing the amount of phosF~orus can
adversely influence melt viscosity and properties. It
WO95t2~135 2 1 6 5 0 8 1 PCT~95/01414
increases the risk of the melt (which contains iron and
little or no alkali metal and low aluminium) undergoing
phase separation and cryætA~ tion. This leads to the
for~ation and accumulation of solid or slag material in or
on the apparatus being used for forming the melt and
~o"v~Ling the melt to fibres, and can cause increased
amount of shot formation during the fibre-formation
~LGOeSS, re~l~c~ material efficiency and higher costs.
It would therefore be desirable to form NNVF wool
having solubility characteristics of the type which would
be expected in such wool from the use of relatively high
phosphorus content while avoiding the manufacturing
problems associated with relatively high phocrhorous
contents.
These problems tend to increase as the content of
phosphate in the melt increases. For instance difficulties
may arise as the content of phosphate increases ~e~U~ld 5%.
It may be possible with some furnaces to use up to 10%
pho~phate but in general for ~LG~_Sing p~L~& ~ it i8
undesirable to inG~ more than thi~.
H~eV~, even at low levels of alumina, and in
particular when it is not possible to provide a melt having
very low levels of ~lumina, dissolution rates of the fibres
are not as high as may be desirable at these levels of
rhosrh~te.
Therefore it would be desirable to improve the
solubility of MNV fibres in the physiological medium
without the nc_- ity for using amounts of phosphate which
lead to ~LG.-;~ing problems.
Fibres con~A ~ n i ng rhQsrhsrus and boron are mentioned
in W094/23801, from which this application claims priority.
Accordinq to the invention there is provided MMVF wool
formed of fibres formed from a composition comprising, by
wei~ht of QYi ~C (with iron expressed as FeO):
SiO2 35-66%
Al203 up to 10%
CaO 10-45%
woss/2sl3s 2 1 6 5 0 8 1 PCT~95/0141
MgO 2-30%
FeO up to 10%
NazO + K20 0-7S
Tio2 0-10%
P205 + B2o~ and other elements - up to 20S
and which includes both P205 and B2C~.
We find surprisingly that the use of a phosphate- and
boratc ~G~ n ~ nq melt can give fibres with adequate
physiologi~al solubility pro~nce~ from a melt which has a
combination of good processing, viscosity and temperature
characteristics, especially when the amount of Al203 is low.
We find that an upper limit of lOS on the amount of
phosphate assists in reducing manufacturing problems,
especially phase separation. The amount is preferably 6%
or less and is ~ y below 5~. We find that inclusion of
borate increases the physiological solubility of the fibres
without the n~e~sity for using larger amounts of
phosphate~ and allows the use of phosphate even in amounts
below 5% whilst ret~i n ~ ng adequate physiological
solubility. We also find that borate has the additional
advantage that it im~Lov B the physical properties of the
melt, in parti ~ r it assists in reducing the melting
po$nt of the melt so that the risk of phase separation is
re~- ~eA.
We also find that the use of boron in pho~rhQrus-
cont~n~n~ fibres results in im~ ed fibre ~Lu~elLies.
For inst~nce tensile ~en~h, mo~ of elasticity and
length to diameter ratio can be im~u~. Te~cile ~Lenyuh
can be ~700 MPa. Fibre ~odulus of Elasticity can be <150
GPa. Length to fibre ratio can be >700, ~pec~ y when
the fibre~ are made by a ~ Ae spinner.
The melt viscosity of the composition at 1400C is
preferably 10-70 poise, preferably 15 to 30 poise.
The fibres preferably have a dissolution rate at pH
7.5 of at le~st 30nm/day, and preferably at least 50 or at
least 60nm/day, when measured by the stationary set up
~ WO95/29135 2 1 6 5 0 8 1 PCT~P9S/01414
method described in Environmental Health Perspectives, Vol.
102, Supplement 5, October 1994, pages 83-86.
The wool of the invention may be provided in any known
way. According to the invention we also provide ~ ~Gce-s
of production of NMVF wool formed of fibres having a
composition aO defined above,
the process comprising
providing raw materials to give the composition,
providing a furnace,
placing the raw materials in the furnace and heating
them to a temperature between 1,400C and 1,600C to
produce a melt,
fiberising the melt, and
collecting the fibres as a wool.
In this ~oce~s we find all the advantages in
processing characteristics ~i~c~s~ above. Preferably the
wool of the invention are made by this ~ oceOs of the
invention.
In the ~LO~eoô of the invention the raw materials used
to produce the melt may be any known raw materials which
give the constituents of the composition. For instance,
raw materials which may be used include ~i~h~r?, cement,
clay, olivine sand, silica sand, waOte fo~,d~y sand,
rasorite, colemanite and other bo~o.. _~nl~n;n~ materials,
CG~ve~ Ler slag, blast-furnace slag, electric arc furnace
slag~ iron oxide, waste stone wool, waOte asbestos, lime,
soda, glass waste, dolomite, bauxite, iron silicate,
kaoline, c~ m phosphate, quartz sand and other known
melt ingredients.
The melt composition and hence the composition of the
produced fibres preferably comprises at least 45%, often at
least 47 or 48%, sio2. The amount is usually below 64 or
65%,preferably below 60~. Often the amount of sio2 is
- from 53.5 to 64%.
The composition preferably has a low alumina content,
generally below 6% and preferably below 4%. In general it
is very ~Ype~ive to provide raw materials which contain no
WO 9S/29135 2 1 6 5 0 8 1 PCT/EP9S101414
alumina at all, so Alz03 is present to some extent, usually
in amounts of at least o.5~, al~holyh alumina amounts are
generally kept as low as poæsible, preferably below 3 or
2~. Amounts of 1-4% are often suitable.
The composition ll~--A lly comprises at least 5%,
generally at least 10% and preferably at least lS% ~ n~
earth metal Q~S (CaO and MgO). Generally the amount is
not more than 50~. Preferably CaO is cont~ine~ in amounts
of bet~ccn 10 and 35S. In some compositions amounts of 10-
20% are preferred but in others amounts of 15 to 30% are
preferred. MgO iæ usually present in an amount of at least
1%, often 5 to 20%, preferably 7 to 20%. For instance it
may be in the range 5-15%.
The composition contains iron, and the amount is up to
10% by weight of total composition, measured a8 FeO.
Preferably iron is present in amounts o~ at least o.S or
1%. Amounts of up to 4% are often suitable but amounts
may be up to 9 or 10%, e.g., in the range 6.5-9%.
The composition may comprise Alk~l~ metals (Na20 and
K20) in amounts of 0% up to 6% or 7S. In general Na20 i8
present in amounts of 0% up to 4~ and R20 is present in
amounts up to 2S. Usually e~ch is ~ t in an amount of
at least 0.1%, but both are opt~on~l and can be omitted.
~ho~l~h~te i5 present in the composition, yen-rally in
amounts of between O.S and 10%, measured a5 P20s, and often
in the range 3 to 6%. For ~ o~e~sing ~uL~-e~ it is
desirable to keep the amount of rhs~rh~te as low as
possible whilst i.,~o~ ating ~nol~gh to give an adeguate
dissolution effect. Pre~erably the ~ho~k~te amount
i8 at least 0.5 but below 5S (e.g., up to 4.5%), more
- preferably below 4%. US~11Y it is at least 2% or 3%~
Borate is il.~oL~GLated in useful amounts of up to 10%,
measured as B2C~. The amount i8 preferably above 0.5 or 1~.
In general, e,~ l should be added to increase suitably the
physiological dissolution rate, but i,.~oL~o~ation of large
amounts of borate n~essitat~s the use of very ~Yr~ncive
raw materials. Amounts of borate below 5% (e.g., 4.5 and
~ W095/29135 2 1 6 5 0 8 1 PCT~P95/01414
below) can give good results at economic cost but amounts
up to 7 or 8% are sometimes preferred. The amount must be
sufficient to give a useful effect and so is normally above
0.5 or 1% and preferably it is at least 3%. The amount of
v 5 B203 is usually below the amount of P205 for re~ronc of
economy.
Tio2 is optional. Tf present, its amount i8 ~ 1 ly
0.1 to 2%. The melt composition may addit;on~lly compri~e
o to 20% of other ingredients, for instance BaO, ZnO, ZrO2,
F2~ MnO, Li2o~ SrO. The total amount of other ingredients
is usually not more than 5%, or at most 10%.
The composition of the melt and of the fibres
particularly preferably comprises:
SiO2 45-64%, preferably 47-60 or 48-60%
Al203 0.5 to 4%
CaO 10-35~,
MgO 5-20~, preferably 5-15 or 7-15
FeO 1-10%, preferably 1 to 9%
Na20 0 to 4%
X20 0 to 2%
Tioz o to 2%
P205 at least 0.5% but preferably below 5%
B2a~ at least 0.5% but preferably below 5%
other elements 0 to 5%
all percentages being by weight of total composition and
iron Q~q being measured as FeO.
The raw materials are placed in a ft~rn~ce where they
are heated to a temperature L~-ee.. 1,400C and 1,600C in
order to produce a melt. In ye,.c al, they are heated to at
30 least 1,450C, preferably Letl_~...... 1,450 and 1,540C,
y~ne~ally around l,480C to 1,520C.
The furnaces which can be used in the invention for
forming the melt which is to be fiberised include cupola
furnaces, oil and/or gas fired ~haft or tank furnaces or
electric furnaces. In these furnaces the invention is
part~c~ rly advantageous, al~ho?~h the composition also
WO95/29135 2 1 6508 1 PCT~P95/01414 ~
shows advantages when using other known types of furnace.
Preferred furnaces are those in which significant amounts
of air are drawn. Slag formation and any volat~ tion
problems can be minimised by the invention.
The melt is fiberised in any known manner. In
particular it may be fiberised by pouring into a fast-
rotating cup having a substantially horizontal base and
perforated side walls out of which iæ thrown as fi~res, or
by pouring onto one or more Sp~nn~n~ wheels. The or each
wheel is mounted on a separate horizontal axis. Melt
poured onto the circumference of the spinning wheel is
flung off as fibres. Although a single wheel can be used,
preferably a c~c~ system is used in which the melt is
poured onto the top rotor of a set of rotating rotors each
mounted about a different substantially horizontal axis and
arranged such that the melt is th~own from the top rotor
onto the subseguent rotor, or on each --~h~equent rotor in
sequence, in the set so as to throw mineral fibres off the
or each subsequent rotor into a collection chamher. Any
apparatus known for the fiberisation of mineral melts to
form wool may be used but a particularly preferred
apparatus is described in our patent publication
W092/06047.
The fibres may then be collected as web or batt. The
web may be cross-lArpe~ to form a batt. The batt may be
consolidated into the desired MMVF wool product in known
manner.
Binder i8 u5u~1ly included in the batt. For instance
it may be sprayed into the fibres before they are collected
as a web or batt.
The wool may be in ~he form of ~h~r~ batts or other
elements or it may be in the form of tufts or granulates of
mineral wool fibres, or in the form of art~cles made from
such tufts or ganulates.
The MMVF wool may be used for any of the conventional
~u-~o~es of MMVF wool, for instance as a horticultural
~ WO95/29135 2 1 6 5 0 8 1 PCT~Pg5l0l4l4
growing medium, for sound or heat insulation and
protection, for fire resistance and protection and as a
filler or reinforcement.
The following are examples of suitable compositions,
S (determined by X-ray flu~ analysis and measured as
weight ~) and their di~solution rate at pH 7.5 in nm per
day. ~ach composition can be melted in a cupola furnace
and fiberised as in W092/06047.
Compositions 1, 2, 3 and 4 are within the invention
while lA, lB, 2A, 3A and 4A are apparoximate comparisons
and ~how that omitting the boron re~ es dissolution rate.
The comparative, borate free, compositions tend to slag
formation, especially with the higher phosrhorous contents.
WO 9S/29135 2 1 6 5 0 8 1 PCT/EP95/01414
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