Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Cellular products or processes of preparing a cellular...
Reexamination Certificate
2002-04-05
2004-07-20
Cooney, Jr., John M. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Cellular products or processes of preparing a cellular...
C521S099000, C521S107000, C521S109100, C521S170000
Reexamination Certificate
active
06765035
ABSTRACT:
The present invention is concerned with the use of a fire retardant in preparing rigid foams and flexible foams and with compositions comprising such fire retardant.
The use of fire retardants in preparing polyurethane foams has been widely described. J02153967 discloses a polyurethane foam containing expandable graphite and a fire-retardant agent such as tris(2-chloroethyl)phosphate. EP-A-192888 discloses a polyurethane foam containing a fire-retardant agent comprising expandable graphite and optionally other compounds such as phosphorous compounds. J51009197 discloses a polyurethane foam containing a fire-retardant agent comprising e.g. tricresylphosphate, where the foam further comprises carbonaceous fibers.
Further conventional flexible polyurethane foams are widely known. Such foams show a relatively high resilience (ball rebound), a relatively low modulus, a relatively high sag factor and a relatively low hysteresis loss. Such foams further show a major glass-rubber transition below ambient temperature, generally in the temperature range of −100° C. to −10° C. The commonly applied relatively high molecular weight polyether and polyester polyols in such foams are responsible for the sub-ambient glass transition temperature (Tg
s
). These polyether and polyester polyols are often referred to as soft segments. Above Tg
s
the foam displays its typical flexible properties until softening and/or melting of the isocyanate-derived urethane/urea clusters (“hard domains”) takes place. This softening and/or melting temperature (Tg
h
and/or Tm
h
) often coincides with the onset of thermal degradation of polymer segments. The Tg
h
and/or Tm
h
for flexible polyurethane foams is generally higher than 100° C., often even exceeding 200° C. At the Tg
s
a sharp decrease of the modulus of the flexible foam is observed. Between Tg
s
and Tg
h
/Tm
h
the modulus remains fairly constant with increasing temperature and at Tg
h
/Tm
h
again a substantial decrease of the modulus may take place. A way of expressing the presence of Tg
s
is to determine the ratio of the Young's storage modulus E′ at −100° C. and +25° C. as per Dynamic Mechanical Thermal Analysis (DMTA measured according to ISO/DIS 6721-5). For conventional flexible polyurethane foams the
E
′
100°
C
.
E
′
+
25
°
C
.
ratio
is
at
least
25.
Another feature of Tg
s
by DMTA (ISO/DIS 6721-5) is that for conventional flexible polyurethane foams the maximum value of the ratio of
Young
'
s
loss
modulus
E
″
Young
'
s
storage
modulus
E
′
(
tan
δ
max
.
)
over the −100° C./+25° C. temperature range varies from 0.20-0.80 in general. The Young's loss modulus E″ is measured by DMTA (ISO/DIS 6721-5) as well.
In patent application PCT/EP9601594 a completely new class of flexible polyurethane foams is described such foams having no major glass-rubber transition between −100° C. and +25° C. In more quantitative terms these foams show a ratio
E′
−100° C.
/E′
+25° C.
of 1.3 to 15.0, preferably of 1.5 to 10 and most preferably of 1.5 to 7.5. The tan
&dgr;max
over the −100° C. to +25° C. temperature range is below 0.2.
The apparent core density of such foams may range from 4-30 kg/m
3
and preferably ranges from 4-20 kg/m
3
(measured according to ISO/DIS845). Such foams are made by crushing a rigid foam.
PCT/EP9806888 discloses a process substantially according to the one of PCT/EP9601594, carried out in the presence of a fire retardant wherein the fire retardant is selected from 1) polybrominated diphenyl ethers; 2) dialkyl esters of polybrominated phthalic acid; 3) compounds of formula P(O)XYZ, wherein X, Y and Z are independently selected from the groups —R and —OR wherein R is an aryl or aralkyl group having 6-12 and preferably 6-10 carbon atoms; 4) mixtures of the compounds 1, 2 and 3 and 5) mixtures of another fire retardant with any of the compounds 1, 2 and 3 or with mixtures of the compounds 1, 2 and 3.
In the context of the present application hereinafter a flexible polyurethane foam is a crushed foam having a ball rebound (measured according to ISO 8307) of at least 40%, preferably at least 50% and most preferably 55-85% in at least one of the three dimensional directions and a sag factor (CLD 65/25) of at least 2.0 (measured according to ISO 3386/1). Preferably such flexible foams have a Young's storage modulus at 25° C. of at most 500 kPa, more preferably at most 350 kPa and most preferably between 10 and 200 kPa (Young's storage modulus measured by DMTA according to ISO/DIS 6721-5). Further, such flexible foams preferably have a sag factor (CLD 65/25) of at least 3.5 and most preferably 4.5-10 (measured according to ISO 3386/1). Still further such flexible foams preferably have a CLD hysteresis loss (ISO 3386/1) of below 55%, more preferably below 50% and most preferably below 45%.
In the context of the present patent application hereinafter a rigid polyurethane foam is an uncrushed foam having a ball rebound measured in the direction of foam rise of less than 40% (ISO 8307 with the proviso that no preflex conditioning is applied, that only one rebound value per sample is measured and that test pieces are conditioned at 23° C.±2° C. and 50±5% relative humidity) and/or having a CLD 65/25 sag factor measured in the direction of foam rise of less than 2.0 (ISO 3386/1 with the proviso that the sag factor is determined after the first load—unload cycle); these properties both being measured at a core density of the foam of 3-27 kg/m
3
(ISO 845). Preferably the ratio E′
−100° C.
/E′
+25° C .
of such a rigid foam is 1.3-15. If in the present application ISO 8307 and ISO 3386/1 are mentioned in relation to rigid foams they refer to the tests as described above including the provisos.
In the context of the present invention the following terms have the following meaning:
1) isocyanate index or NCO index or index:
the ratio of NCO-groups over isocyanate-reactive hydrogen atoms present in a formulation, given as a percentage:
[
NCO
]
×
100
[
active
hydrogen
]
(
%
)
.
In other words the NCO-index expresses the percentage of isocyanate actually used in a formulation with respect to the amount of isocyanate theoretically required for reacting with the amount of isocyanate-reactive hydrogen used in a formulation.
It should be observed that the isocyanate index as used herein is considered from the point of view of the actual foaming process involving the isocyanate ingredient and the isocyanate-reactive ingredients. Any isocyanate groups consumed in a preliminary step to produce modified polyisocyanates (including such isocyanate-derivatives referred to in the art as quasi or semi-prepolymers and prepolymers) or any active hydrogens consumed in a preliminary step (e.g. reacted with isocyanate to produce modified polyols or polyamines) are not taken into account in the calculation of the isocyanate index. Only the free isocyanate groups and the free isocyanate-reactive hydrogens (including those of the water) present at the actual foaming stage are taken into account.
2) The expression “isocyanate-reactive hydrogen atoms” as used herein for the purpose of calculating the isocyanate index refers to the total of active hydrogen atoms in hydroxyl and amine groups present in the reactive compositions; this means that for the purpose of calculating the isocyanate index at the actual foaming process one hydroxyl group is considered to comprise one reactive hydrogen, one primary amine group is considered to comprise one reactive hydrogen and one water molecule is considered to comprise two active hydrogens.
3) Reaction system: a combination of components wherein the
Eling Berend
Lindsay Christopher Ian
Seeley Gordon John
Cooney Jr. John M.
Graham Nicole
Huntsman International LLC
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