SEALANTS

PRODUITS D'ETANCHEITE

English Abstract

2149018 9411455 PCTABS00032
A fire retarding sealant comprises a silicone resin, a filler, a
ceramic fire retardant such as zinc borate, a smoke suppressant
such as stearate coated calcium hydroxide, and either aluminium
hydroxide or magnesium hydroxide, preferably the former. The
sealant is intumescent, and non-setting, and is intended for placement
around pipes, cables and service penetrations in walls, floors
and ceilings. At the temperatures encountered in fires, the
aluminium hydroxide decomposes to form aluminium oxide and steam, the
latter causing the sealant to intumesce while being relatively
harmless to people (no halogen gases are evolved). The aluminium
oxide and zinc borate form a crust on the intumesced sealant,
providing a further fire retardant property.

Claims

- 5 ?
CLAIMS
1. A non-setting sealant comprising a silicone gum
having a molecular weight of from 250000 to 550000, a
filler, a ceramic dire retardant, a smoke suppressant,
and an intumescent compound which is either aluminium
hydroxide or magnesium hydroxide.
2. A sealant according to claim 1 in which the
intumescent compound is aluminium hydroxide.
3. A sealant according to claim 2 containing up to
40% of aluminium hydroxide.
4. A sealant according to any preceding claim in
which the ceramic fire retardant is zinc borate.
5. A sealant according to any preceding claim
containing at least 30% by weight of the silicone resin.
6. A sealant according to any preceding claim
containing from 10% to 20% by weight of the filler.
7. A sealant according to any preceding claim in
which the smoke suppressant is stearate coated calcium
carbonate.
8. A sealant according to any preceding claim further
comprising one or more of a surfactant, a plasticiser, a
preservative, a pigment, a toolability improver and a
rheology modifier.
9. A sealant according to any preceding claim further
comprising activated graphite or sodium silicate as a
high pressure intumescent additive.
10. A sealant according to any preceding claim further
comprising copper activated zinc sulphide as a luminous
pigment.

Description

WO94~l1455 2 1 ~ 9 ~ l 8PCT/~B93/02321
-- 1 --
TITL~
Sealants
DESCRIPTION ~.
The inventlon relates to a sealant whlch is silic~-ne
based and has non-setting and _ire-retarding --~
in,umescing properties.
It is known that fire retarding sealants mav be place^
around pipes, cables and service penetrations in WG~
floors and ceilings. However, such sealan~s mav preve-.
access for servicing purposes.
The inventlon provides a sealant com-rislns a silic--_
resin, a filler, a ceramic fire retaraant, a sm^~e
su?~ressant, and either aluminium hy~oxide or magnes:_m
hydroxide.
The sealant according to the inven :~n h_a in.umes_^-.
pro?erties derived from the aluminium o- magnes:um
hvdroxide. Its fire retarding proper~ies a~e enh_nced ^i
the inclusion of the ceramic fire retardant, whic;. __
preferably zinc borate. The pre~erred hvdre.Yide i-
aluminium hydroxide. At a temperatu-e o- abou~ 200_,
this compound decomposes to form 21 uminium oYiae a-.~
steam, the latter causing the sealant to intumes_e whi:e
bei~g relatively harmless to people. The aluminium oxi--
and zinc borate form a crust on the intumesced seal_-..
providing a further fire retardant ?roperty. ~t ~he
temperatures encountered in fire~, the magnes _m
hydroxide behaves in a corresponding manner.
~, ~
The sealant according to the invention, ~eing p acec :n
the service penetration, will thus intumes_e u---.
exposure to heat in a fire, effec.ivel~ sealins _-.
spaces in the penetration which would allow -ire _?.-
smo~e to pass into another containe~ area. Since ~

2 ~9 ~ PCT/GB93/0232l j`
scalan~ 1S non-set-lng, nowever, lt can be -emoved arter
nstaliation -o- servlcing purposes. F~ ermore the
s~alant lS solven. ~ee and haloaen ~re-- and ~ not
e~-olve halogen gases upon lntumescence.
mhe sealant accordlng to the inven~ rere ably
contains a mlnlmum o- 30,' by welght o_ .~e heat-curing
silicone resin, and 10 to 20,' by weight 5-- fliler. The
silicone resin used is commercially availas_a as silicone
gum. The sillcone gum may have a molecu a- welght of
about 250000 to ~0000 and a penetration ~est value of
_bout 600 .o 900. Other silicone resins ~,ay De used in
-ne compounding o~ the sealant. Althoua.~ manv _illers
could be used, dolomite is preferred on ~he crounas of
whiteness and economy.
The aluminium hydroxide preferably consti._~es up to 40%
by weight of the sealant. The amount _ in~umescence
increases with the amount of aluminium hva~oxid-.
The sealant according to the invention may further
contain any additives customarily incluaed in such
compositions. These may include sur-actants,
?lasticisers, preservatives, pigments, tool-~bility
(shaping and forming) improvers and rheolo3y modifiers.
So called "high pressure" intumescent prooucts, such as
activated graphite and sodium silicate, may also be
added.
It is especially preferred to add a lu~inous pigment
suchas copper-activated zinc sulphide. This pigment
luminesces in the absence of light, and may act as a
visual identi ication of the grade of seaia..t to building
inspectors and rire prevention officers, b_th on initial
and subsequent inspections. -

WO94/114~5 ~ 4 9 ~ PCT/G~93/02321
n ~ st-ate- b~ _oll-wlng ~xam~ies:
. -~~_ r~.ard-nt i~ mes__nt n~ se~-:nc ~eal~ 2a
p--_a-e~ ^v com~ounding th2 -ol ~wing as _stanc s n
N2-ben ~ixer:
O ~ ~ w 2 i ~s ;~. ~
al--. 2 , omega - ~ivinvlpolvdimet:~.v' a lloxane,
o~ _:-h-, omega - dimethvl?olvdime nvlsi oxa.r.e -~8.1/~
ini_m ;-var^xide ~'.
S.-_-a-2 ^_ated calcium c2-bon2t- ~.7/-
~o:~mi ~
t~ : .281
. O O O
In -lis com~osition, the s.2-rate coate- c__~ona e is c
smc:~2 s~?~ressar.t and rheolocv moc- ier ~3 ~rever.~ _lum~_
o~ ~he ?roduc~. The zinc bo-_-e is -~-e re~_~ding
en~.ancinc the __re retardan. ~-o?e-.ies ^_ ~;~e com~cund.
The com~osition is a non-setting, hanc ma 'eable ~aste
ca~able o- ext-usion into -ope -orm or c~s~om c-c iled
forms. _t had a Smoke Index cf 23 -s dete-mine^
ac~~rding to Naval Engineering Standard 711, Isse 2 and 2
~ox -i.v Index of 0.19 as determine~ bv ~avcl _ngineering '~
Standarc' 713, lssuê 3.
The ~cllo~-ing -esults have been obta~ne- ~v -es.inc t
ac-_rdlng to the stated British S~andards: ~
'.
BS ~/6: D2rt 6 (1989) ~lèSS 'C~
; 3S ~.75: 3a.. 7 (1987) ~'ass '^'
~ S - / ~ 3 _ ' ~ 20 (1987) ~ -5

WO94/1145~ ~" ~, ~J ~ , PCT/GB93/02321
A
' Q ~ ? p e n d i X .~ - C l ause A c <
_~ O~ ''8-) .~pendlx , - Ciaus~ B.-.' .~3 ~. 0
_ - o ~ ~ ~ '' Q ~ cpendix ~ us- ~.-............... .~o!O~ Q,
.~o(OF.-)'.-
.' .
;am_
i .`. -i-e -etardan intumescer.t luminous r.on-se.tlng se-lan~
-re?2reà 25 described ln Exampl- 1, but tc ~_
t - - ' 7 ~ 1 n~ compcsition:
,' bv ~eiar.
__-.-a, ome~_ - di~-inv'?olvcimeth~ _ilox_r.Q,
-- a_-:._, omega - dimethylpolvdime~hvl__loxane 30.1
.. : m:n-_m hvc oxide '`.22S
~ a - coatQ~ cal_ium carbonate ~.,/
__:om_.e 1~ 4
bc-at 'e 1^~
- a- ~ivated ~inc sul?hide ^.o00
1 OQ . O O C!
~-~ ^c??er activated zinc sul?hiàe ~igment ?ro~iaQs
:_min^s~tv to the composition. ~he inc~usi^n c- t~e
__-pe- activa.ed zinc sul?hide doe~ no~ a ec, ~h-
--_?e-~ es or performance as detai~ed in Example 1.