Note: Descriptions are shown in the official language in which they were submitted.
CA 02856356 2014-05-20
WO 2013/093057 PCT/EP2012/076764
1
INSULATING ELEMENT FOR THE INSULATION OF FLAT ROOFS
The invention relates to a thermal insulating element for the insulation of
flat
roofs, a roof insulation system and the use of the thermal insulating element
on
flat roofs.
Insulating elements for flat roofs are required to have a number of different
properties. As with all insulating elements for buildings, a high level of
thermal
insulation is important, as is fire resistance. Furthermore, flat roofs must
be
insulated in such a way that it is possible for roofers and other construction
workers to stand and walk on top of the insulating elements. This means that
the flat roof insulation must have high compressive strength as well as high
point
load resistance.
One conventional solution has been to use mineral fibre boards of high
density.
Such roofing boards have the advantages of high rigidity, high compressive
strength and high point load resistance. They are also non-combustible.
In recent years, however, environmental concerns have led to a trend in which
building regulations now require an increased thickness of insulation on flat
roofs. This results in the insulating elements having an increased weight,
which
causes great disadvantages in the installation process. This in turn leads to
increased labour and equipment costs in the installation process. Therefore, a
need exists to minimise the weight of insulation elements, whilst maintaining
their fire resistance, insulating properties and still meeting the need for
sufficient
rigidity, compressive strength and point load resistance to allow construction
workers to stand and walk on the roof.
In the context of mineral wool insulating elements, decreasing the average
weight of mineral wool both decreases the cost of the insulation and improves
the thermal insulation properties. However, this decrease in density also
results
in a decrease in rigidity and compressive strength, which is unacceptable in
insulating elements for use on flat roofs.
CA 02856356 2014-05-20
WO 2013/093057 PCT/EP2012/076764
2
A number of solutions have been proposed. One approach to minimising the
weight of the insulating element is to employ relatively low density mineral
wool
lamellae with a hard plate on top. The lamellae are strips in which the
mineral
fibres are oriented with a significant component that is perpendicular to the
plane
of the roof and the top plate. The top plate is usually a high density mineral
fibre
board. The orientation of the fibres in the lamellae allows a relatively high
resistance to compression to be achieved, together with a relatively low
density.
The lamellae alone are not sufficiently rigid to permit a person to stand or
walk
on top of them safely. Therefore, a rigid force distributing top plate is
required to
ensure that it is possible to walk on the insulation elements.
Often, the lamellar strips are supplied and laid individually, with the rigid
top
plate being laid subsequently. This system has the obvious disadvantage that
installation costs are increased by the need to lay many lamellar strips
individually in particular due to a constraint on the width of the lamellar
strips,
which is a result of the production process. A further disadvantage is that
the
use of lamellae results in a reduction in thermal insulation as compared with
when the mineral fibres are predominantly oriented parallel to the surface
being
insulated.
A similar solution has been to use prefabricated lamellar boards, as described
in
EP 0560878 B1 and EP 1709132 B1. The use of these boards decreases the
installation time and cost, but the lamellae used are generally of a higher
density, meaning that the weight of each board becomes a disadvantage.
The lamellae of these known products are manufactured by fibrising a mineral
melt, supplying a binder to the fibres, collecting the fibres as a web,
cutting the
fibre web in the longitudinal direction to form lamellae, cutting the lamellae
into
desired lengths, turning the lamellae 90 about their longitudinal axis and
bonding the lamellae together to form boards.
A further alternative is the use of dual density roof boards. These are
described,
for example, in EP 1456444 and EP 1456451. In each case, a continuously
produced mineral fibre web is separated depth-wise into upper and lower sub-
CA 02856356 2014-05-20
WO 2013/093057 PCT/EP2012/076764
3
webs. At least the upper sub-web is subjected to thickness compression, before
being re-joined with the lower sub-web. The combined web is then cured. The
upper layer of mineral fibre boards made by this process has a density of 100
to
300 kg/m3. The density of the lower layer is usually from 50 to 150 kg/m3.
These dual density boards, therefore, provide sufficient insulation and are
suitable for being walked upon due to the high density top layer. However, in
order to have sufficient compressive strength, the density of the lower layer
is
still relatively high, so the overall weight of the board makes it difficult
to install,
especially when the board is very thick. Therefore, it would be desirable to
reduce the overall density and weight of the roof board.
One attempt to improve the compressive strength of an insulating board without
a corresponding increase in the density is described in W000/70161. The
insulating element is designed as a one-piece panel element with at least one
insulating part of high heat insulating capacity and at least one load-
dissipating
fillet, made of mineral wool, which has an increased compressive strength in
comparison with the mineral wool material of the insulating part and is
permanently bonded to the insulating part forming an integral component part
of
the panel element. The presence of the fillet allows the density of the
insulating
part to be reduced, whilst still maintaining a reasonable level of compressive
strength. It would, however, be desirable to further increase the compressive
strength and resistance to compression of insulating elements for flat roofs.
EP 450731 discloses a panel-type insulation element, in particular for roofs
or
outside walls, comprising at least one layer of panel material such as
chipboard
or plywood and wool material. In one embodiment, a layer of wool material is
provided, on either side of which there is a layer of foam material as the
panel
material. The layer of wool material can be provided with cut-outs running in
the
thickness direction in each of which there is a plug of foam material joining
the
layers of foam material on either side of the layer of wool material. The
resulting
product is said to be light, and have good thermal insulation. The presence of
a
standard foam material such as polyurethane, however, increases the
CA 02856356 2014-05-20
WO 2013/093057 PCT/EP2012/076764
4
combustibility of the product. Furthermore, it would be desirable to further
increase the resistance to compression of the insulating element.
Therefore, it is an object of the invention to provide an insulating element
for roof
insulation that is relatively light and has a relatively low density. A
further object
is to provide an insulating element that has good thermal and acoustic
insulation
properties. It is also an object of the invention to provide an insulating
element
having a high level of fire resistance. Finally it is a further object of the
invention
to provide an insulating element that has a high compressive strength and
resistance to compression and has an upper surface suitable for being walked
upon.
By "resistance to compression", it is meant that a high level of pressure is
required to compress a product by a given amount. For a given material, this
is
related to the "compression modulus of elasticity", which can be measured
according to European standard EN 826:1996.
In a first aspect, the invention provides a thermal insulating element
comprising
an insulating layer having a first face and a second face, said insulating
layer
comprising a coherent man-made vitreous fibre-containing insulating material
and at least one reinforcing element extending substantially from the first
face to
the second face of the insulating layer, wherein the reinforcing element
comprises a polymeric foam composite material, the composite material
comprising a polymeric foam and man-made vitreous fibres produced with a
cascade spinner or a spinning cup, wherein at least 50% by weight of the man-
made vitreous fibres present in the foam composite material have a length less
than 100 micrometers.
One main advantage of the thermal insulating element of the invention is its
low
overall weight and density. In one embodiment, the average density of the
complete element is 30 to 100 kg/m3, preferably 40 to 80 kg/m3, most
preferably
50 to 70 kg/m3.
CA 02856356 2016-03-22
The low density of the thermal insulating element means that thicker
insulating
elements can be more easily handled. Preferably the thickness of the
insulation
element is at least 50 mm, more preferably at least 100 mm, and most
preferably
at least 120 mm.
5
In a further aspect, the invention provides a roof insulation system,
preferably a
flat roof insulation system, comprising:
a roof support,
at least one thermal insulating element according to the invention
arranged on top of the roof support, and
a cover layer on top of the thermal insulating element.
In a further aspect, the invention provides the use of the thermal insulating
element in a flat roof insulating system.
The thermal insulating element according to the invention comprises an
insulating layer and a polymeric foam composite material as described below.
Polymeric Foam Composite Material
The invention makes use of the polymeric foam composite material described in
our earlier application filed on 18 August 2011 and having the application
number EP 11177971.6.
The polymeric foam composite material used in the present invention can be
produced from a foamable composition comprising a foam pre-cursor and man-
made vitreous fibres, wherein at least 50% by weight of the man-made vitreous
fibres have a length of less than 100 micrometres.
The weight percentage of fibres in the polymeric foam composite material or in
the foamable composition above or below a given fibre length is measured with
a sieving method. A representative sample of the man-made vitreous fibres is
placed on a wire mesh screen of a suitable mesh size (the mesh size being the
CA 02856356 2014-05-20
WO 2013/093057 PCT/EP2012/076764
6
length and width of a square mesh) in a vibrating apparatus. The mesh size can
be tested with a scanning electron microscope according to DIN IS03310. The
upper end of the apparatus is sealed with a lid and vibration is carried out
until
essentially no further fibres fall through the mesh (approximately 30 mins).
If the
percentage of fibres above and below a number of different lengths needs to be
established, it is possible to place several screens with incrementally
increasing
mesh sizes on top of one another. The fibres remaining on each screen are
then weighed.
According to the invention, the man-made vitreous fibres present in the
polymeric foam composite must have at least 50% by weight of the fibres with a
length less than 100 micrometres as measured by the method above.
By reducing the length of man-made vitreous fibres that are present in the
foamable composition and in the polymeric foam composite, a larger quantity of
fibres can be included in the foamable composition before an unacceptably high
viscosity is reached. As a result, the compressive strength, fire resistance,
and
in particular the compression modulus of elasticity of the resulting foam can
be
improved. Previously, it had been thought that ground fibres having such a low
length would simply act as a filler, increasing the density of the foam.
However,
by using mineral fibres with such a high proportion of short fibres, far
higher
levels of fibres can be incorporated into the foam precursor and the resulting
foam. The result of this is that significant increases in the compressive
strength
and, in particular, the compression modulus of elasticity of the foam can be
achieved.
Preferably, the length distribution of the man-made vitreous fibres present in
the
polymeric foam composite or foamable composition is such that at least 50% by
weight of the man-made vitreous fibres have a length of less than 75
micrometres, more preferably less than 65 micrometres.
Preferably, at least 60% by weight of the man-made vitreous fibres present in
the polymeric foam composite or foamable composition have a length less than
CA 02856356 2014-05-20
WO 2013/093057 PCT/EP2012/076764
7
100 micrometres, more preferably less than 75 micrometres and most preferably
less than 65 micrometres.
Generally, the presence of longer man-made vitreous fibres in the polymeric
foam composite or foamable composition is found to be a disadvantage in terms
of the viscosity of the foamable composition and the ease of mixing.
Therefore,
it is preferred that at least 80%, or even 85 or 90% of the man-made vitreous
fibres present in the polymeric foam composite or foamable composition have a
length less than 125 micrometres. Similarly, it is preferred that at least
95%,
more preferably at least 97% or 99% by weight of the man-made vitreous fibres
present in the polymeric foam composite or foamable composition have a length
less than 250 micrometres.
The greatest compressive strength can be achieved when at least 90% by
weight of the fibres have a length less than 100 micrometers and at least 75%
of
the fibres by weight have a length less than 65 micrometers.
Man-made vitreous fibres having the length distribution discussed above have
been found generally to sit within the walls of the cells of the foam
composite,
without penetrating the cells to a significant extent. Therefore, it is
believed that
a greater percentage by weight of the fibres in the composite contribute to
increasing the strength of the composite rather than merely increasing its
density.
It is also preferred that at least some of the fibres, for example at least
0.5% or
at least 1% by weight, have a length less than 10 micrometers. These very
short
fibres are thought to be able to act as nucleating agents in the foam
formation
process. The action of very short fibres as nucleating agents can favour the
production of a foam with numerous small cells rather than fewer large cells.
The fibres present in the polymeric foam composite or in the foamable
composition can be any type of man-made vitreous fibres, but are preferably
stone fibres. In general, stone fibres have a content by weight of oxides as
follows:
CA 02856356 2014-05-20
WO 2013/093057 PCT/EP2012/076764
8
Si02 25 to 50%, preferably 38 to 48%
A1203 12 to 30%, preferably 15 to 28%
TiO2 up to 2%
Fe203 2 to 12%
CaO 5 to 30%, preferably 5 to 18%
MgO up to 15%, preferably Ito 8% or 4 to 10%
Na20 up to 15%
K20 up to 15%
P205 up to 3%
Mn0 up to 3%
B203 0 to 3%.
These values are all quoted as weight (:)/0 oxides, with iron expressed as
Fe203, as is conventional.
An advantage of using fibres of this composition, especially in the context of
polyurethane foams, is that the significant level of iron and alumina in the
fibres
can act as a catalyst in formation of the foam. This effect is particularly
relevant
when at least some of the iron in the fibres is present as ferric iron, as is
usual
and/or when the level of A1203 is particularly high such as 15 to 28% or 18 to
28%.
Composites including stone fibres of the above composition have also been
found to have improved fire resistance as compared with composites in which
the filler used does not contain a significant level of iron.
An alternative stone wool composition useful in the invention, has oxide
contents
by weight in the following ranges:
Si02 37 to 42%
A1203 18 to 23%
CaO + MgO 34 to 39%
Fe203 up to 1%
Na20 + K20 up to 3%
These values are all quoted as weight (:)/0 oxides, with iron expressed as
Fe203,
as is conventional.
CA 02856356 2014-05-20
WO 2013/093057 PCT/EP2012/076764
9
Again, the high level of alumina in fibres of this composition can act as a
catalyst
in the formation of a polyurethane foam.
Whilst stone fibres are preferred, the use of glass fibres, slag fibres and
ceramic
fibres is also possible.
The man-made vitreous fibres present in the polymeric foam composite and
foamable composition are produced with a cascade spinner or a spinning cup.
Traditionally, fibres produced by these methods have been used for insulation,
whilst continuous glass fibres have been used for reinforcement in composites.
Continuous fibres (e.g. continuous E glass fibres) are known to be stronger
than
discontinuous fibres produced by cascade spinning or with a spinning cup (see
"Impact of Drawing Stress on the Tensile Strength of Oxide Glass Fibres", J.
Am.
Ceram. Soc., 93 [10] 3236-3243 (2010)). Nevertheless, the present inventors
have surprisingly found that foam composites comprising short, discontinuous
fibres have a compressive strength that is at least comparable with foam
composites comprising continuous glass fibres of a similar length. This
unexpected level of strength is combined with good fire resistance, a high
level
of thermal insulation and cost efficient production.
In order to achieve the required length distribution of the fibres, it will
usually be
necessary for the fibres to be processed further after the standard production
method. The further processing will usually involve grinding or milling of the
fibres for a sufficient time for the required length distribution to be
achieved.
Usually, the fibres present in the polymeric foam composite and foamable
composition have an average diameter of from 2 to 7 micrometres, preferably
from 2 to 6 or from 3 to 6 micrometers. In one preferred embodiment, the
fibres
have an average diameter of from 3 to 4 micrometres. In another preferred
embodiment, the fibres have an average diameter of from 5 to 6 micrometres.
Thin fibres as preferred in the invention are believed to provide a higher
level of
thermal insulation to the composite than thicker fibres, but without a
significant
CA 02856356 2014-05-20
WO 2013/093057 PCT/EP2012/076764
reduction in strength as compared with thicker fibres as might be expected.
The
average fibre diameter is determined for a representative sample by measuring
the diameter of at least 200 individual fibres by means of the intercept
method
and scanning electron microscope or optical microscope (1000x magnification).
5
The foamable composition that can be used to produce the polymeric foam
composite comprises a foam precursor and man-made vitreous fibres. The
foam precursor is a material that either polymerises (often with another
material)
to form a polymeric foam or is a polymer that can be expanded with a blowing
10 agent to form a polymeric foam. The composition can be any composition
capable of producing a foam on addition of a further component or upon a
further processing step being carried out.
Preferred foamable compositions are those capable of producing polyurethane
foams. Polyurethane foams are produced by the reaction of the polyol with an
isocyanate in the presence of a blowing agent. Therefore, in one embodiment,
the foamable composition comprises, in addition to the man-made vitreous
fibres, a polyol as the foam precursor. In another embodiment, the foamable
composition comprises, in addition to the man-made vitreous fibres, an
isocyanate as the foam precursor. In another embodiment, the composition
comprises a mixture of an isocyanate and a polyol as the foam precursor.
If the foam precursor is a polyol, then foaming can be induced by adding a
further component comprising an isocyanate. If the foam precursor is an
isocyanate, foam formation can be induced by the addition of a further
component comprising a polyol.
Suitable polyols for use either as the foam precursor or to be added as a
further
component to the foamable composition to induce foam formation are
commercially available polyol mixtures from, for example, Bayer Material
Science, BASF or DOW Chemicals. Commercially available polyol compositions
often comprise water, which can act as a chemical blowing agent in the foam
formation process.
CA 02856356 2014-05-20
WO 2013/093057 PCT/EP2012/076764
11
The isocyanate for use either as the foam precursor or to be added as a
further
component to the foamable composition to induce foam formation is selected on
the basis of the density and strength required in the foam composite as well
as
on the basis of toxicity. It can, for example, be selected from methylene
diphenyl
diisocyanate (MDI), toluene diisocyanate (TDI), hexamethylene diisocyanate
(HDI) and isophorone diisocyanate (IPDI), MDI being preferred. One
particularly
suitable example is diphenylmethane-4,4'-diisocyanate. Other
suitable
isocyanates are commercially available from, for example, Bayer Material
Science, BASF or DOW Chemicals.
In order to form a foam composite, a blowing agent is required. The blowing
agent can be a chemical blowing agent or a physical blowing agent. In some
embodiments, the foamable composition comprises a blowing agent.
Alternatively, the blowing agent can be added to the foamable composition
together with a further component that induces foam formation.
In the context of polyurethane foam composites, in a preferred embodiment, the
blowing agent is water. Water acts as a chemical blowing agent, reacting with
the isocyanate to form CO2, which acts as the blowing gas.
When the foam-precursor is a polyol, in one embodiment, the foamable
composition comprises water as a blowing agent. The water is usually present
in such a foamable composition in an amount from 0.3 to 2 % by weight of the
foamable composition.
As an alternative, or in addition, a physical blowing agent, such as liquid
CO2 or
liquid nitrogen could be included in the foamable composition or added to the
foamable composition as part of the further component that induces foam
formation.
The foamable composition, in an alternative embodiment, is suitable for
forming
a phenolic foam. Phenolic foams are formed by a reaction between a phenol
and an aldehyde in the presence of an acid or a base. A surfactant and a
blowing agent are generally also present to form the foam. Therefore, the
CA 02856356 2014-05-20
WO 2013/093057 PCT/EP2012/076764
12
foamable composition could comprise, in addition to the man-made vitreous
fibres, a phenol and an aldehyde (the foam precursor), a blowing agent and a
surfactant. Alternatively, the foamable composition could comprise as the foam
precursor, a phenol but no aldehyde, or an aldehyde but no phenol.
Whilst foamable compositions suitable for forming polyurethane or phenolic
foams are preferred, it is also possible to use foamable compositions suitable
for
forming polyisocyanurate, expanded polystyrene and extruded polystyrene
foams.
The foamable composition that can be used to make the foam composite used in
the invention can contain additives in addition to the foam precursor and the
man-made vitreous fibres. When it is desired to include additives in the foam
composite, as an alternative to including the additives in the foamable
composition comprising man-made vitreous fibres, the additive can be included
with a further component that is added to the foamable composition to induce
foam formation.
As an additive, it is possible for the composition or the foam composite to
comprise a fire retardant such as expandable powdered graphite, aluminium
trihydrate or magnesium hydroxide. The amount of fire retardant in the
composition is preferably from 3 to 20% by weight, more preferably from 5 to
15% by weight and most preferably from 8 to 12 % by weight. The total quantity
of fire retardant present in the polymeric foam composite material is
preferably
from Ito 10%, more preferably from 2 to 8% and most preferably from 3 to 7 %
by weight.
Alternatively, or in addition, the foamable composition or foam composite can
comprise a flame retardant such as nitrogen- or phosphorus-containing
polymers.
The fibres used in the polymeric foam composite can be treated with binder,
which, as a result, can be included in the composition and the resulting foam
composite as an additive if it is chemically compatible with the composition.
The
CA 02856356 2014-05-20
WO 2013/093057 PCT/EP2012/076764
13
fibres used usually contain less than 10% binder based on the weight of the
fibres and binder. The binder is usually present in the foamable composition
at a
level less than 5% based on the total weight of the foamable composition. The
foam composite usually contains less than 5% binder, more usually less than
2.5% binder. In a preferred embodiment, the man-made vitreous fibres used are
not treated with binder.
In some circumstances, it is advantageous, before mixing the man-made
vitreous fibres into the foamable composition, to treat the fibres with a
surfactant,
usually a cationic surfactant. The surfactant could, alternatively, be added
to the
composition as a separate component. The presence of a surfactant, in
particular a cationic surfactant, in the composition and as a result in the
polymeric foam composite material has been found to provide easier mixing and,
therefore, a more homogeneous distribution of fibres within the foamable
composition and the resulting foam.
One advantage of the described polymeric foam composite is that it is possible
to incorporate larger percentages of fibres into the foamable composition, and
therefore into the resulting foam, than would be the case with longer fibres.
This
allows higher levels of fire resistance and compressive strength to be
achieved.
Preferably, the composition comprises at least 15% by weight, more preferably
at least 20% by weight, most preferably at least 35% by weight of man-made
vitreous fibres. The polymeric foam composite material itself preferably
comprises at least 10% by weight, more preferably at least 15% by weight, most
preferably at least 20% by weight of man-made vitreous fibres.
Usually the foamable composition comprises less than 85% by weight,
preferably less than 80%, more preferably less than 75% by weight man-made
vitreous fibres. The resulting foam composite usually contains less than 80%
by
weight, preferably less than 60%, more preferably less than 55% by weight man-
made vitreous fibres.
The polymeric foam composite used in the invention comprises a polymeric
foam and man-made vitreous fibres. The foam composite can be formed from
CA 02856356 2014-05-20
WO 2013/093057 PCT/EP2012/076764
14
the foamable composition as described above. It is preferred that the
polymeric
foam is a polyurethane foam or a phenolic foam. Polyurethane foams are most
preferred due to their low curing time.
The first step in the production of the polymeric foam composite material is
to
form the foamable composition comprising the foam precursor and the mineral
fibres. The fibres can be mixed into the foam precursor by a mechanical mixing
method such as use of a rotary mixer or simply by stirring. Additives as
discussed above can be added to the foamable composition.
Once the fibres and foam precursor have been mixed, the formation of a foam
can then be induced. The manner in which the foam is formed depends on the
type of foam to be formed and is known to the person skilled in the art for
each
type of polymeric foam. In this respect, reference is made to "Handbook of
Polymeric Foams and Foam Technology" by Klempner et al.
For example, in the case of a polyurethane foam, the man-made vitreous fibres
can be mixed with a polyol as the foam precursor. The foamable composition
usually also comprises water as a chemical blowing agent. Then foaming can be
induced by the addition of an isocyanate.
In the case where a further component is added to the foamable composition to
induce foaming, this can be carried out in a high pressure mixing head as
commercially available.
In one embodiment, foam formation is induced by the addition of a further
component and the further component comprises further man-made vitreous
fibres, wherein at least 50% by weight of the further man-made vitreous fibres
have a length of less than 100 micrometres. Including man-made vitreous fibres
in both the foamable composition and the further component can increase the
overall quantity of fibres in the foam composite, by circumventing the
practical
limitation on the quantity of fibres that can be included in the foamable
composition itself.
CA 02856356 2014-05-20
WO 2013/093057 PCT/EP2012/076764
For example in the context of polyurethane foam composites a foamable
composition could comprise a polyol, man-made vitreous fibres and water. Then
foaming could be induced by the addition, as the further component, of a
mixture
of isocyanate and further man-made vitreous fibres, wherein at least 50% of
the
5 man-made vitreous fibres have a length of less than 100 micrometers.
In essentially the same process, the mixture of isocyanate and man-made
vitreous fibres could constitute the foamable composition, and the mixture of
polyol, water and man-made vitreous fibres could constitute the further
10 component.
The quantity of man-made vitreous fibres in the further component is
preferably
at least 10 (:)/0 by weight, based on the weight of the further component.
More
preferably the quantity is at least 20% or at least 30% based on the weight of
the
15 further component. Usually, the further component comprises less than
80% by
weight, preferably less than 60%, more preferably less than 55% by weight man-
made vitreous fibres.
The polymeric foam composite is the material that provides compressive
strength and resistance to compression to the thermal insulating element.
Therefore, preferably the polymeric foam composite has a compressive strength
of at least 1500 kPa and a compression modulus of elasticity of at least
60,000
kPa as measured according to European Standard EN 826:1996.
The following are examples of the polymeric foam composite materials as used
in the invention as compared with other polymeric foam composite materials.
Example 1 (comparative)
100.0 g of a commercially available composition of diphenylmethane-4,4'-
diisocyanate and isomers and homologues of higher functionality, and 100.0 g
of
a commercially available polyol formulation were mixed by propellers for 20
seconds at 3000 rpm. The material was then placed in a mold to foam, which
took about 3 min. The following day, the sample was weighed to determine its
CA 02856356 2014-05-20
WO 2013/093057 PCT/EP2012/076764
16
density and the compression strength and compression modulus of elasticity
were measured according to European Standard EN 826:1996.
Compressive strength: 1100 kPa
Compression modulus of elasticity: 32000 kPa
Example 2
100.0 g of the same commercially available polyol formulation as used in
Example 1 was mixed with 200.0 g ground stone wool fibres, over 50% of which
have a length less than 64 micrometers, for 10 seconds. Then 100.0 g of the
commercially available composition of diphenylmethane-4,4'-diisocyanate was
added and the mixture was mixed by propellers for 20 seconds at 3000 rpm. The
material was then placed in a mold to foam, which took about 3 min. The
following day, the sample was weighed to determine its density and the
compression strength and compression modulus of elasticity were measured
according to European Standard EN 826:1996.
Compressive strength: 1750 kPa
Compression modulus of elasticity: 95000 kPa
Example 3 (comparative)
100.0 g of the same commercially available polyol formulation as used in
Examples 1 and 2 was mixed for 10 seconds with 50.0 g stone fibres having a
different chemical composition from those used in Example 2 and having an
average length of 300 micrometers. 100.0 g of the commercially available
composition of diphenylmethane-4,4'-diisocyanate was added. The mixture was
then mixed by propellers for 20 seconds at 3000 rpm. The material was placed
in a mold to foam, which takes about 3 min. The following day, the sample was
weighed to determine its density and the compression strength and compression
modulus of elasticity were measured according to European Standard EN
826:1996.
CA 02856356 2014-05-20
WO 2013/093057 PCT/EP2012/076764
17
Compressive strength: 934 kPa
Compression modulus of elasticity: 45000 kPa
Example 4
Example 3 was repeated, but the fibres were ground such that greater than 50%
of the fibres had a length less than 64 micrometers. Following this grinding
it
became possible to mix 200g of the fibres with the polyol mixture.
Compressive strength: 1785 kPa
Compression modulus of elasticity: 115000 kPa.
Example 5
Small flame tests were carried out to establish the fire resistance of
polyurethane
composites used in the invention as compared with the fire resistance of
composites comprising sand rather than fibres according to the invention. The
fibres used had a composition within the following ranges.
5i02 38 to 48%
A1203 15 to 28`)/0
TiO2 up to 2%
Fe203 2 to 12%
CaO 5 to 18%
MgO 1 to 8%
Na20 up to 15`)/0
K20 up to 15%
P205 up to 3%
MnO up to 3%
B203 0 to 3%
The sand used had a particle size up to 2mm. In each composite tested,
expanding graphite was included as a fire retardant. The
test involved
measuring the height of a flame from each composite under controlled
conditions. The results were as follows:
CA 02856356 2014-05-20
WO 2013/093057 PCT/EP2012/076764
18
Fibre Content Sand Content Graphite Content Flame height (cm)
(wt%) (wt%) (wt%)
25 0 8 12-17
25 0 10 7
31 0 10 5
0 25 8 22
0 25 10 11
0 31 10 12
The Insulating Layer
The insulating layer of the thermal insulating element of the invention
comprises
a coherent man-made vitreous fibre-containing insulating material and at least
one reinforcing element extending substantially from the first face to the
second
face of the insulating layer.
The term "coherent" means that the man-made vitreous fibre-containing
insulating material is not in the form of a granulate or any other loose
insulating
material.
The coherent man-made vitreous fibre-containing insulating material is
preferably mineral wool. The man-made vitreous fibres in the coherent man-
made vitreous fibre-containing insulating material can be glass fibres,
ceramic
fibres, slag wool fibres or any other type of man-made vitreous fibre, but
they are
preferably stone fibres. Stone fibres have a content by weight of oxides as
follows:
5i02 25 to 50%, preferably 38 to 48%
A1203 12 to 30%, preferably 15 to 28%
TiO2 up to 2%
Fe203 2 to 12%
CaO 5 to 30%, preferably 5 to 18%
MgO up to 15% preferably Ito 8%
CA 02856356 2014-05-20
WO 2013/093057 PCT/EP2012/076764
19
Na20 up to 15%
K20 up to 15%
P205 up to 3%
MnO up to 3%
B203 0 to 3%.
These values are all quoted as oxides, as is conventional.
The man-made vitreous fibres present in the coherent man-made vitreous fibre-
containing insulating material can be produced by standard methods such as
with a cascade spinner or a spinning cup. Usually, the fibres are treated with
a
binder and collected as a web, before being cured.
In order to provide a thermal insulating element having as low weight and
overall
density as possible, it is preferred that the coherent man-made vitreous fibre-
containing insulating material has a density less than 60 kg/m3, more
preferably
less than 50 kg/m3. Since the coherent man-made vitreous fibre-containing
insulating material contributes only a very minor portion, if any, of the
compressive strength of the insulating layer, it is possible for this material
to
have such low density. Usually, the density of the coherent man-made vitreous
fibre-containing insulating material is at least 20 kg/m3, more usually at
least 30
kg/m3.
The main purpose of the coherent man-made vitreous fibre-containing insulating
material is to provide a high level of thermal insulation. Therefore, it is
preferred
that the coherent man-made vitreous fibre-containing insulating material has a
thermal conductivity of less than 40 mW/m=K, more preferably less than 35
mW/m=K and most preferably less than 33 mW/m=K.
In order to provide a good level of insulation, the insulating layer should
have a
reasonable thickness. In one embodiment, the thickness of the insulating layer
is from 80mm to 350mm, preferably from 100 to 300mm, more preferably from
120 to 250mm.
CA 02856356 2014-05-20
WO 2013/093057 PCT/EP2012/076764
The density of the insulating layer should be kept to a minimum, whilst
maintaining sufficient compressive strength and resistance to compression.
Preferably the density of the insulating layer is from 25 to 60 kg/m3, more
preferably from 35 to 50 kg/m3.
5
The Reinforcing Element
The thermal insulating element of the invention comprises an insulating layer,
which includes a reinforcing element made of a polymeric foam composite
10 material as described above. In the thermal insulating element of the
invention,
at least one reinforcing element extends substantially from the first face to
the
second face of the insulating layer. The purpose of the reinforcing element is
to
increase the compressive strength and resistance to compression of the
insulating elements. When a plate is disposed at one face of the insulating
layer
15 (either a top plate that is part of the thermal insulating element or a
separate
plate that is laid on top of the insulating layer during installation), this
allows the
insulating element to have sufficient strength to allow a construction worker
to
stand and walk on the insulating element safely.
20 The reinforcing element or elements can take any shape or form, which
allow
them to confer compressive strength and resistance to compression to the
thermal insulating element.
Typically, in order to achieve this goal, it is
necessary for the reinforcing element to extend substantially from the first
face of
the insulating layer to the second face of the insulating layer, because the
coherent man-made vitreous fibre-containing insulating material generally has
a
very low compressive strength and resistance to compression. In
one
embodiment the reinforcing elements are shaped as columns. The columns can
have any suitable cross-sectional shape. In one embodiment, the columns are
cylindrical. However the shape of the columns can also be somewhat irregular.
The number of columns in a thermal insulating element depends on a number of
factors, including the size of the insulating element, the diameter of the
columns
and their separation from one another. Generally, however, the thermal
insulating element comprises at least 3 columns, preferably at least 4
columns.
CA 02856356 2014-05-20
WO 2013/093057 PCT/EP2012/076764
21
Often the thermal insulation element has as many as between 25 and 400
columns per m2, more often between 40 and 200 columns per m2, such as
around 100 columns per m2.
In order to provide maximum stability and compressive strength, it is
preferred
that the columns are close to perpendicular to the first and second faces of
the
insulating layer. Preferably, the columns are less than 20 degrees, more
preferably less than 10 degrees and more preferably less than 5 degrees from
being perpendicular to the first and second faces of the insulating layer.
Most
preferably the columns are substantially perpendicular to the first and second
faces of the insulating layer.
In order to provide sufficient strength, the columns are preferably at least
10 mm
in diameter at their narrowest point, more preferably at least 15 or 20 mm in
diameter at their narrowest point. Usually, it is not necessary for the
columns to
be wider than 50 or 40 mm at their narrowest point.
The columns extend substantially from the first face to the second face of the
insulating layer, so their length usually corresponds substantially with the
thickness of the insulating layer.
It is not desirable for the columns to be positioned too far apart from each
other,
which would result in large bending stresses being exerted on the top plate,
when walked upon, whilst positioning the columns too close too each other
would to some extent increase the cost and the weight of the insulating
element.
Therefore, in a preferred embodiment, columns are positioned from 5 to 20 cm
from their nearest neighbour or neighbours. More preferably, columns are
positioned from 7 to 15 cm from their nearest neighbour or neighbours.
Generally the columns are positioned in rows.
In an alternative embodiment, the reinforcing elements are plate-shaped. The
plates can be completely flat, curved or somewhat jagged. It is not necessary
for the surfaces of the plates to be perfectly flat. It is even acceptable for
the
plates to have some holes in them. In order to provide sufficient strength,
the
CA 02856356 2014-05-20
WO 2013/093057 PCT/EP2012/076764
22
plate-shaped reinforcing elements preferably have a thickness at their
thickest
point of at least 3 mm, more preferably at least 4 mm. In order to avoid
excess
weight and cost, the thickness is not usually greater than 30 mm at the
thickest
point, more usually less than 20 mm at the thickest point.
Generally, in order to provide maximum compressive strength and stability, the
plates are oriented close to perpendicular to the first and second faces of
the
insulating layer. Preferably, the plates are less than 20 degrees, more
preferably less than 10 degrees and more preferably less than 5 degrees from
being perpendicular to the first and second faces of the insulating layer.
Most
preferably the plates are substantially perpendicular to the first and second
faces
of the insulating layer.
It is also preferred that the plate-shaped reinforcing elements run through
the
plane of the insulating layer parallel to one another. In an alternative
embodiment, however, at least one plate-shaped reinforcing element runs
through the plane of the insulating layer in a direction that is perpendicular
to
that in which at least one other reinforcing element runs through the plane of
the
insulating layer. This embodiment provides increased stability to the thermal
insulating element.
When the insulating layer includes plates running substantially parallel to
each
other through the plane of the insulating layer, the distance between those
plates
is substantially the same at all points. Preferably the distance between those
plates is from 7 cm to 25 cm, more preferably from 10 cm to 20 cm.
Top Plate
In order to allow construction workers to walk on the insulating element of
the
invention, it is necessary, eventually, to provide the insulating element with
a top
plate. In some embodiments, however, the insulating layer can be provided
without a top plate and a separate top plate can be provided at the point of
installation. Therefore, a top plate is not an essential feature of the
invention. In
one embodiment, however, the thermal insulating element comprises a top plate.
CA 02856356 2014-05-20
WO 2013/093057 PCT/EP2012/076764
23
The top plate is disposed on at least one face of the insulating layer. This
can
be the first face or the second face or, in a particular embodiment, both the
first
face and the second face.
In a preferred embodiment, the top plate comprises man-made vitreous fibres
and binder and has a density of at least 100 kg/m3. The man-made vitreous
fibres in the top plate can be any suitable fibres such as glass fibres,
ceramic
fibres or slag fibres, but are preferably stone fibres. In a more preferred
embodiment, the top plate has a density of at least 150 kg/m3 or at least 180
kg/m3, such as around 200 kg/m3. The density of the top plate may also be
substantially higher, such as around 600 kg/m3, or even higher, depending on
the circumstances. Typically a top plate of this type is sufficiently rigid
and has
sufficient point load resistance to allow a construction worker to walk or
stand on
the thermal insulating element even at points in between the reinforcing
elements.
Preferably, the top plate has a bending strength of at least 7 N/m2 and a
point
load resistance of at least 500 kN.
It is possible to use polymeric foam as the top plate material, but a high
density
mineral fibre board is preferred due to its good bending strength and fire
resistance properties. In a particular embodiment, the top plate is produced
according to the method set out in International Application
PCT/EP2011/069777, which have a particularly high level of strength.
In order to have good strength, preferably, the top plate has a thickness of
at
least 3 mm, more preferably at least 5 mm and most preferably at least 10 mm.
However, in order to keep the overall density and weight of the thermal
insulating element to a minimum it is preferred that the top plate has a
thickness
of less than 40 mm, more preferably less than 30 mm.
The overall density of the thermal insulating element, when it includes a top
plate
is generally in the range 50-80 kg/m3.
CA 02856356 2014-05-20
WO 2013/093057 PCT/EP2012/076764
24
The top plate can be affixed to the insulating layer, for example by use of an
adhesive, or it can be a separate top plate that is arranged on top of the
insulating layer as indicated above.
In a particularly advantageous embodiment, the top plate or top plates and the
reinforcing element can be bonded together without any extrinsic attachment
means such as an adhesive. This can be achieved by forming the polymeric
foam material in situ and contacting the top plate with the foam composite
material as it hardens. This technique has been found to produce a
particularly
strong connection between the top plate and the reinforcing element,
particularly
when the top plate comprises man-made vitreous fibres and binder and has a
density of at least 100kg/m3, such as at least 150 kg/m3, such as around 200
kg/m3.
Roof Insulation Systems
The present invention also relates to roof insulation systems, in particular
flat
roof insulation systems. As used herein, the term "flat roof" means a roof
that is
substantially horizontal, even though it might be sloping at an angle of up to
5 or
10 degrees to the horizontal.
The insulation systems of the invention comprise a roof support, at least one
thermal insulating element according to the invention arranged on top of the
roof
support, and a cover layer arranged on top of the thermal insulating element.
Generally, in the context of flat roofs, the roof support comprises at least
one
corrugated steel plate or is a concrete deck. The remaining layers of the roof
insulation system can differ depending on whether the roof support is a
corrugated steel plate or a concrete deck.
When the roof support comprises at least one corrugated steel plate, it is
preferred that a water vapour barrier is arranged between the corrugated steel
plate and the thermal insulating elements. Often, the water vapour barrier is
a
polymer membrane. The water vapour barrier ensures that moisture from humid
CA 02856356 2014-05-20
WO 2013/093057 PCT/EP2012/076764
air beneath the roof does not enter into the roof insulation through openings
in
the corrugated steel plates or through joints between the steel plates.
For fire safety reasons it is sometimes preferred that a man-made vitreous
fibre
5 board is arranged between the corrugated steel plate and the water vapour
barrier layer. Preferably the man-made vitreous fibre board has a density of
at
least 100 kg/m3. Preferably the man-made vitreous fibre board has a thickness
of between 30 mm and 70 mm, more preferably between 40 mm and 60 mm.
10 The thermal insulating element can be any thermal insulating element
according
to the invention as described above, but in order to ensure that it is
possible to
walk on the flat roof once it has been constructed, it is preferred that the
thermal
insulating element comprises a top plate that is disposed on at least one face
of
the insulating layer. In an alternative embodiment, however, the thermal
15 insulating element does not comprise a top plate, but a separate plate
is laid on
top of the thermal insulating element at the point of installation. The
separate
plate preferably comprises man-made vitreous fibres and binder and has a
density of at least 100 kg/m3.
20 When the roof support is a corrugated steel plate, the positioning and
orientation
of the thermal insulating element can be important. It is preferred,
especially
when there is no man-made vitreous fibre board positioned between the thermal
insulating element and the roof support, that the thermal insulating element
is
positioned such that at least 1, and preferably more, of the reinforcing
elements
25 are positioned over the peaks of the corrugated steel plates, so that
there is
sufficient support for the insulating element to allow roofers to walk on top
of it.
When the reinforcing elements are plate-shaped, it is preferred that the plate-
shaped reinforcing elements do not run parallel with the peaks and troughs in
the corrugated steel plate. It is especially preferred that the plate-shaped
reinforcing elements run at an angle of at least 45 degrees or more preferably
substantially perpendicular to the peaks and troughs in the steel plates.
CA 02856356 2014-05-20
WO 2013/093057 PCT/EP2012/076764
26
When the roof support is a concrete deck, the system can be somewhat simpler.
In particular, there is no need for a fire safe man-made vitreous fibre board
below the vapour barrier, since the concrete deck provides sufficient fire
protection itself.
The roof insulation system of the invention comprises a cover layer on top of
the
thermal insulating elements. The cover layer is the uppermost layer of the
roof
system and provides weather protection for the roof. Preferably, the cover
layer
comprises a bituminous sub-layer and a top layer. The top layer is preferably
a
bituminous top layer or a polymeric film. In embodiments where the top layer
is a
polymeric film, it is preferably a PVC film.
In the roof insulation systems of the invention, the thermal insulating
element is
preferably secured to the roof support by mechanical fastening means as is
well
known in the art of flat roof construction.
Description of Drawings
Figure 1 shows a thermal insulating element 10 according to the invention in
which the reinforcing elements are columns 11. The columns 11 extend from
the first face 12 to the second face 13 of the insulating layer and a top
plate 14 is
disposed on the first face 12 of the insulating layer. The columns 11 are
substantially perpendicular to the first face 12 and the second face 13 of the
insulating layer. Coherent man-made vitreous fibre-containing insulating
material forms the majority of the insulating layer in terms of volume. In the
shown embodiment the columns 11 are arranged in a square pattern. The
distance between the columns 11 is 100 mm, such that there are 100 columns
per m2.
Figure 2 shows another embodiment of the thermal insulating element 110 of the
invention, in which the reinforcing elements 111 are plate-shaped. The
reinforcing elements 111 extend substantially from the first face 112 to the
second face 113 of the insulating layer. They run through the plane of the
insulating layer substantially parallel to each other. The plate-shaped
reinforcing
CA 02856356 2014-05-20
WO 2013/093057 PCT/EP2012/076764
27
elements 111 are also substantially perpendicular to the first face 112 and
the
second face 113 of the insulating layer. A top plate 114 is disposed on the
first
face 112. Again, coherent man-made vitreous fibre-containing insulating
material forms the majority of the insulating layer in terms of volume. In the
shown embodiment the distance between the plate-shaped reinforcing elements
111 is 150 mm.
In preferred embodiments the insulating element 10,110 comprises 4 to 20% by
weight, preferably 6 to 15% by weight, more preferably 8 to 12% by weight, of
the polymeric foam composite material which forms the reinforcing elements
11,111.
Figure 3 shows a roof insulation system according to the invention. The system
comprises a roof support in the form of at least one corrugated steel plate
20. A
thermal insulating element 10 provided with a top plate 14 is arranged on top
of
the corrugated steel plate 20. The thermal insulating element is of the type
shown in Figure 1, i.e. the insulating layer comprises man-made vitreous fibre-
containing insulating material provided with columns 11 of a polymeric foam
composite material.
A vapour barrier 21 is arranged between the corrugated steel plate 20 and the
thermal insulating element 10, and a cover layer 22 is arranged on top of the
top
plate 14.
In some embodiments for a roof insulation system according to the invention a
fire protection board (not shown) can be arranged between the corrugated steel
plate 20 and the vapour barrier 21. The fire protection board may be made of
man-made vitreous fibres.
In other embodiments the roof support is a concrete deck instead of a
corrugated steel plate. However, generally the roof insulation system above
the
roof support is similar to what is shown in Figure 3.
CA 02856356 2014-05-20
WO 2013/093057 PCT/EP2012/076764
28
Figure 4 is an environmental scanning electron microscope image of a
polyurethane foam composite according to the invention, in which the fibres
have a length distribution such that 95% by weight of the fibres have a length
below 100 micrometers and 75% by weight of the fibres have a length below 63
micrometers. The composite contains 45% fibres by weight of the composite.
The instrument used was ESEM, XL 30 TMP (W), FEI/Philips incl. X-ray
microanalysis system EDAX. The sample was analysed in low vacuum and
mixed mode (BSE/SE).
The image shows the cellular structure of the foam and demonstrates that the
man-made vitreous fibres generally sit in the walls of the cells of the foam
without penetrating into the cells themselves to a significant extent.
