U.S. patent application number 13/322710 was filed with the patent office on 2012-03-29 for wall form units and systems.
This patent application is currently assigned to BASF SE. Invention is credited to Ian Stuart Biggin, Martin Peter Butters.
Application Number | 20120073226 13/322710 |
Document ID | / |
Family ID | 40902313 |
Filed Date | 2012-03-29 |
United States Patent
Application |
20120073226 |
Kind Code |
A1 |
Biggin; Ian Stuart ; et
al. |
March 29, 2012 |
WALL FORM UNITS AND SYSTEMS
Abstract
A wall form unit for containing a pourable, curable construction
material for forming a wall section integrating said wall form unit
and said construction material, comprising a first panel and a
second panels spaced apart in predetermined relation thereby
forming a hollow between first and second panels for defining said
wall section and at least one tie assembly having a spacer member
for maintaining said first and second panel in predetermined
relation, in which both the first panel and second panels are rigid
and adapted to retain said construction material, wherein the first
panel is constructed of a thermally insulating material and the
second panel is constructed of a thermally conducting material. A
wall form system for forming a section of wall and wall section and
method for constructing same are also defined. The invention also
relates to a panel for use in forming a wall form unit and also
claims a kit for constructing a wall form unit.
Inventors: |
Biggin; Ian Stuart; (East
Riding Of Yorkshire, GB) ; Butters; Martin Peter;
(West Yorkshire, GB) |
Assignee: |
BASF SE
LUDWIGSHAFEN
DE
|
Family ID: |
40902313 |
Appl. No.: |
13/322710 |
Filed: |
May 20, 2010 |
PCT Filed: |
May 20, 2010 |
PCT NO: |
PCT/EP10/57000 |
371 Date: |
November 28, 2011 |
Current U.S.
Class: |
52/309.4 ;
52/309.1; 52/309.13; 52/309.15; 52/426; 52/742.14 |
Current CPC
Class: |
C04B 28/30 20130101;
C04B 28/04 20130101; E04B 2/8617 20130101; F28D 20/023 20130101;
C04B 2201/32 20130101; Y02E 60/145 20130101; C04B 2103/0071
20130101; E04B 2/8635 20130101; Y02E 60/14 20130101; C04B 28/32
20130101; C04B 28/04 20130101; C04B 14/022 20130101; C04B 14/06
20130101; C04B 14/303 20130101; C04B 14/34 20130101; C04B 14/386
20130101; C04B 14/42 20130101; C04B 14/4668 20130101; C04B 14/48
20130101; C04B 20/1029 20130101; C04B 2103/0071 20130101; C04B
2103/63 20130101; C04B 2103/0071 20130101; C04B 24/02 20130101;
C04B 24/026 20130101; C04B 24/085 20130101; C04B 24/36
20130101 |
Class at
Publication: |
52/309.4 ;
52/426; 52/309.1; 52/309.13; 52/742.14; 52/309.15 |
International
Class: |
E04B 2/34 20060101
E04B002/34; E04B 2/86 20060101 E04B002/86; E04C 2/04 20060101
E04C002/04; E04C 2/22 20060101 E04C002/22; E04C 2/20 20060101
E04C002/20; E04C 2/28 20060101 E04C002/28 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 1, 2009 |
GB |
0909280.0 |
Claims
1. A wall form unit, comprising: a first panel comprising a
thermally insulating material, a second panel comprising a
thermally conducting material, a hollow between the first and
second panels, and at least one tie assembly comprising a spacer
member for maintaining the first and second panels spaced apart in
predetermined relation, in which both the first panel and the
second panel are rigid and adapted to retain a construction
material.
2. The wall form unit of claim 1, wherein the first panel
comprises: a composite material and a polymer or a polymer-based
compound.
3. The wall form unit of claim 1, wherein the second panel
comprises: a first component comprising an inorganic binder, a
polymer or a polymer-based compound.
4. The wall form unit of claim 1, wherein the second panel
comprises: a first component comprising an inorganic binder, a
polymer or a polymer-based compound and a second component
comprising graphite, an alumina particle, silica sand, a fine
gravel particle, a stone particle, metallic fiber, metallic mesh,
or a metallic particle.
5. The wall form unit of claim 1, wherein the second panel
comprises a hydraulic inorganic binder.
6. The wall form unit of claim 1, wherein the second panel
comprises magnesia cement.
7. The wall form unit of claim 1, wherein the second panel
comprises magnesia cement comprising particles of sand, or other
additive of high thermal conductivity, distributed throughout the
magnesia cement.
8. The wall form unit of claim 1, wherein the second panel
comprises phase change material (PCM).
9. The wall form unit of claim 1, wherein the second panel
comprises phase change material (PCM) and magnesia or magnesia
cement.
10. The wall form unit of claim 8, wherein the phase change
material (PCM) is microencapsulated.
11. A wall form system, comprising: a core comprising pourable,
curable construction material; a plurality of panels sheathing the
core, wherein the plurality of panels comprises at least two wall
form units adapted for interlocking and wherein each wall form unit
comprises a first panel and a second panel in predetermined
relation, thereby forming a hollow between the first and second
panels for receiving the construction material; and at least one
tie assembly comprising a spacer member for maintaining the first
panels and the second panels in predetermined relation, wherein
both the first panels and the second panels are rigid and adapted
to retain the construction material, the first panel comprises a
thermally insulating material, and the second panel comprises a
thermally conducting material.
12. A kit comprising components suitable for constructing the wall
form unit of claim 1.
13. A wall section, comprising at least two of the wall form units
of claim 1, and a cured construction material in the hollow between
the first and second panels comprising a poured, cured construction
material.
14. A process of erecting a building structure, comprising: i)
arranging a first panel and a second panel of a plurality of
Insulating Concrete Form (ICF) units in predetermined relation for
defining a wall section, such that the first and second panels are
spaced apart to form a hollow between them, ii) connecting at least
one tie assembly comprising a spacer member for maintaining the
first and second panels in predetermined relation, iii) introducing
a pourable, curable construction material into the hollow, and iv)
curing the pourable, curable construction material, wherein both
the first panel and the second panel are rigid and adapted to
retain the construction material, the first panel comprises a
thermally insulating material, and the second panel comprises a
thermally conducting material.
15. The wall form unit of claim 2, wherein the polymer or
polymer-based compound comprises an expanded polystyrene or
polyurethane foam.
16. The wall form unit of claim 3, wherein the second panel further
comprises a second component distributed throughout the first
component, the second component selected from the group consisting
of a thermally conducting particle, a filament, and a mesh.
17. The wall form unit of claim 9, wherein the phase change
material (PCM) is microencapsulated.
18. A wall section comprising the wall form system of claim 11.
19. The wall form unit of claim 16, wherein the second component
comprises iron, copper, aluminum, lead, tin, silver, or a metal
alloy.
20. The wall form unit of claim 16, wherein the first component
forms a matrix within the panel, and wherein the second component
is distributed throughout the matrix.
Description
[0001] This invention relates to wall form units and systems used
to construct structural components such as walls. More
particularly, the present invention relates to thermally conducting
panels for use in wall form units and systems for constructing
walls formed from pourable, curable construction material in which
the form system remains in situ.
[0002] Construction components, such as walls and columns, are
often made from curable construction materials such as concrete. It
is well known to make a specifically shaped component from such
materials in order to build or erect civil engineering structures.
Previously such forms would have been typically made from materials
such as wood. To make the construction component, the form is
erected to create a cavity capable of holding the curable
construction material, for instance concrete, in a liquid form. The
concrete or other curable construction material is then poured or
otherwise introduced into the cavity created by the form and then
allowed to set. Once the material has hardened into a structural
component, the form is removed.
[0003] Alternatively, the form can be built from several form
units, each form unit having a pair of spaced panels. The form
units are placed adjacent to each other, both horizontally and
vertically, to build a complete form. Enhanced efficiency in the
construction of a form may be achieved in such a system. This is
particularly the case where the form units are designed to remain
permanently in situ, once placed, and do not have to be removed
once the concrete, or other curable construction material, has been
poured and allowed to set. One such system has side panels for each
form unit made of an insulated material. These side panels perform
the dual purpose of functioning as side units for the cavity, and
then after the concrete has set, as an insulating layer on each
side of the concrete.
[0004] These wall form units and wall form systems are frequently
referred to as Insulating Concrete Forms (ICFs). The use of
Insulating Concrete Forms or more generally wall form units or
systems is well accepted as very effective building construction
technology.
[0005] Typically an ICF or other wall form units or systems
comprise an expanded plastic (foamed plastic), usually expanded
polystyrene or polyurethane foam, form comprising two spaced apart
panels or hollow blocks.
[0006] ICFs comprising two spaced apart panels will be generally
supplied as a self assembly "flatpack" system comprising the two
panels of foamed plastic and ties or other connecting components
used for assembling the forms, hereinafter referred to as ties.
ICFs are generally locked together by a suitable connecting means,
for instance by use of tongue and groove joints around the edges of
the ICFs, as they are stacked to form walls. Steel rebars or
reinforcing steel mesh can be used in the space between the panels,
into which concrete or other curable construction material is
added, to provide added strength. When steel rebars are used then
these can be in both horizontal and vertical orientation. The forms
are assembled into a hollow vertical wall into which concrete or
other curable construction material is poured thereby creating a
solid wall. The ICF or wall form units remain in place and become a
permanent part of the building and provide insulation. It has been
generally accepted that employing ICFs as a permanent part of the
building provides energy efficiency, contributing to
environmentally responsible practices. As an alternative to
delivering the ICFs to the construction site as a self-assembly
"flatpack" the ICFs may also be delivered as preassembled units. As
a further alternative wall sections may be built from the ICFs off
site and these wall sections may be delivered to the construction
site where the building is to be erected.
[0007] Typical insulating concrete forms are described in Canadian
patents 1244668, 2551250, U.S. Pat. Nos. 4,703,602, 4,731,968,
4,949,515, 5,704,180, 5,724,782, 5,809,728, 5,896,714, US published
patent applications 20040040240, 20040045237, 20080022619,
International applications WO9525207, WO9901626, WO2008009103 and
WO2008136819.
[0008] French patent 2598447 describes a structure comprising a
light weight loadbearing framework. The framework includes cavities
which are closed in on the sites by panels. A material is poured
into the cavity in which the material with high heat storage
capacity and quick setting time in order to form a heat
accumulator. An insulating layer is inserted between the external
facing and the internal panel. Such a complex structure employs
several panels and limited capacity for the construction material
without making the framework excessively deep and intrusive.
[0009] European patent application 1959212 describes a wall element
formed from glass plates with a core material consisting of
microcapsules of phase change material filling the space. However,
such a wall element would be completely unsuitable for retaining a
curable construction material. The filling material incorporated in
this wall element would not be curable.
[0010] PFSolutions describe cement bonded particle board used as a
permanent formwork which is left in place after casting of concrete
on-site on their website www.pfsolutions.ie. The cement bonded
particle board apparently has a thermal conductivity of 0.26 W/mK.
Nevertheless the system is devoid of any thermally insulating panel
in direct contact with the concrete core.
[0011] Although ICFs generally provide a multiple layer of
insulation to walls, buildings constructed from ICF walls tend to
suffer the disadvantage of inadequate temperature regulation to
rooms within the building. The objective of the present invention
is to provide wall form units and systems which overcome this
problem. In particular it would be desirable to provide such wall
form units and systems that are easily transportable and can be
installed easily on-site where the building or other construction
can be erected.
[0012] According to the present invention we provide a wall form
unit for containing a pourable, curable construction material for
forming a wall section integrating said wall form unit and said
construction material, comprising a first panel and a second panel
spaced apart in predetermined relation thereby forming a hollow
between the first and second panels for defining said wall section
and at least one tie assembly having a spacer member for
maintaining said first and second panels in predetermined relation,
in which both the first panel and second panels are rigid and
adapted to retain said construction material, wherein the first
panel is constructed of a thermally insulating material and the
second panel is constructed of a thermally conducting material.
[0013] The invention also provides a wall form system for forming a
wall section having a core of pourable, curable construction
material sheathed by a plurality of panels comprising at least two
wall form units, each said wall form unit having means for
interlocking said wall form units to define said wall section, a
first panel and a second panels spaced apart in predetermined
relation thereby forming a hollow between the first and second
panels for receiving said construction material, and a least one
tie assembly, said tie assembly comprising a spacer member for
maintaining said first panel and said second panels in said
predetermined relation, in which both the first panel and second
panels are rigid and adapted to retain said construction material,
wherein the first panel is constructed of a thermally insulating
material and the second panel is constructed of a thermally
conducting material.
[0014] In accordance with a further aspect of the invention we
provide a kit for constructing a wall form unit in accordance with
the previously stated aspects of the invention.
[0015] The invention also relates to a wall section comprising at
least two wall form units or a wall form system as defined herein
containing a cured construction material between the first and
second panel, which cured construction material has been formed
from a pourable, curable construction material that has been poured
into the hollow between the first and second panels.
[0016] The wall section may often be formed on site where the
building is to be erected. Alternatively the wall section may be
formed at the manufacturer site and shipped to the location where
the building is to be constructed.
[0017] The invention also concerns a novel panel suitable for
constructing a wall form unit according to the aforementioned
aspects of the invention in which said panel is constructed of a
thermally conducting material.
[0018] The present invention also relates to a process of erecting
a building structure which comprises a wall section formed from a
plurality of ICF units comprising the steps, [0019] i) arranging
the first and second panels of the plurality of ICF units in
predetermined relation for defining said wall section such that a
hollow is formed between the first and second panels by spacing
apart the first and second panels in predetermined relation, [0020]
ii) connecting at least one tie assembly having a spacer member for
maintaining for spacing apart said first and second panels in
predetermined relation, [0021] iii) introducing a pourable, curable
construction material into the hollow, [0022] iv) allowing the
pourable, curable construction material to cure, in which both the
first panel and second panel are rigid and adapted to retain said
construction material, wherein the first panel is constructed of a
thermally insulating material and the second panel is constructed
of a thermally conducting material.
[0023] In constructing the wall form unit the second panels should
be placed so that they form the side of the wall that will face the
interior of the building and the first panels should be placed so
that they form the side of the wall that will face the exterior of
the building. The first panels and second panels should be
maintained at a predetermined distance using ties. Into the hollow
created between the first and second panels the pourable, curable
construction material e.g. concrete should be introduced and
allowed to set to form a wall section.
[0024] The pourable, curable construction material once introduced
into the hollow should be in direct contact with the first and
second panels. Once cured the pourable, curable construction
material should form a solid core which is in direct contact with
the first and second panels.
[0025] The inventors believe that by employing panels formed from a
thermally conducting material and a thermally insulating material
respectively each in direct contact with the cured construction
material, for instance concrete, the thermal mass of the cured
construction material can be utilised and this provides for
improved temperature regulation within rooms of buildings whilst
maintaining adequate insulation. The inventors believe that the
reason that the buildings constructed from the prior art ICF walls
tend to suffer the disadvantage of inadequate temperature
regulation to rooms within the building is because of their lack of
accessible thermal mass.
[0026] The pourable, curable construction material which sets to
form the internal core of cured construction material, typically
concrete, exhibits high thermal mass.
[0027] Generally the thermal mass, expressed in terms of specific
heat capacity, will be at least 700 J/kgK and usually at least 800
J/kgK or, more preferably, at least 900 J/kgK for instance as much
as 1000 J/kgK or 1100 J/kgK or more. The density of the concrete
will have a bearing on the heat capacity in volume terms. The
higher the density, the greater is the volumetric heat capacity. It
is therefore preferable to use cured construction materials,
typically concrete based on Portland cement, which have a high
density. The density is generally always >0.5 kg/litre,
preferably >1.0 and most preferably >2.0. The pourable,
curable construction material once cured and solidified may
desirably have an admittance value of between 1 and 6 W/m.sup.2K.
Any concrete normally used for construction purposes may be used in
accordance with the present invention but concrete designed
specifically for ICF applications, such as Rheo Cell (Trade Mark)
ICF concrete from BASF or U Crete (Trade Mark) from Bardon Concrete
are preferable. Waterproof concrete may also be used especially for
basement construction. It may also be desirable to include phase
change material (PCM) to provide additional temperature regulation
within the building. Suitable phase change materials are described
herein in regard to the second panel.
[0028] The dimensions of the first and second panels may be typical
of ICF dimensions commonly used. Suitably the panels may be between
1000 mm and 1500 mm in length, preferably between 1200 and 1300 mm,
for instance around 1220 mm. The height of the first panel and
second panel may be between 350 and 500 mm, preferably between 390
and 450 mm, for instance around 400 to 410 mm. However, in some
situations it may be desirable to use larger dimensions. For
instance, it may be desirable for the panels to be as much as 3000
mm or 4000 mm in length and/or width or larger. Even larger
dimensions could be used if it is found to be practicable. Even
larger dimensions may for instance be up to 10,000 mm in height and
up to 20,000 mm in length.
[0029] The use of large dimensions include ICF structures, which
could be preconstructed in a factory. Typical larger dimension IFC
structures would be analogous the dimensions employed in
HercuWall.TM., made by HercuWall Inc (USA).
[0030] Generally the first and second panels should be strong and
sufficiently hard wearing to avoid being easily damaged during
transportation or especially on the construction site. This would
include during handling, assembly, pouring of concrete, during
curing of the concrete, mechanical and electrical fixing and
subsequent finishing, decoration etc.
[0031] The edges of the first and second panels may be formed to
allow the wall form units (ICFs) to be stacked such that both
horizontal and vertical edges lock into the neighbouring units. The
locking system may be based on tongues and grooves. This may be
achieved by for instance providing the upper edge and left side
with a tongue and the lower edge and right side with a groove such
that each panel may interlock with this neighbouring panel. These
locking systems may be added, cast or cut into the panels during
manufacture or alternatively may be formed by fixing several
thinner panels together to form the tongues and grooves.
[0032] The first and second panels may be further adapted in order
to facilitate better adhesion to the concrete. For instance this
may be achieved by applying grooves or other surface formations on
the sides of the panels intended to face the concrete or other
curable/cured construction material. These grooves, on the second
panels, should also facilitate improved thermal contact between the
panel and the concrete.
[0033] The surface of the second panel facing the interior of the
building, i.e. the opposite side to that in contact with the
concrete or other curable/cured construction material, may also be
adapted for a particular purpose required for the interior of the
building. For instance the interior facing surface of the second
panels may be smooth in order to accept paint or wallpaper or
alternatively it may be brushed or roughened in order to accept
tiles or any other covering where a surface key is desirable. The
second panel may also be faced with suitable scrim e.g. of glass
fibre to improve surface finish, strength or fire resistance
properties.
[0034] The first panel of the wall form units or systems may be any
conventional panel used for forming ICFs. Typically the first panel
may be constructed from a composite material, a polymer or a
polymer-based compound. Suitably the first panel is formed from a
foamed plastic, preferably an expanded polystyrene (for example
Styropor (Trade Mark) from BASF) or polyurethane foam. The first
panel may contain other insulating components with the foamed
plastic, for instance Aerogel (Trade Mark) or vacuum panel
insulation. Additives may be incorporated into the foamed plastic
of the first panel to improve performance such as strength or
insulation characteristics. Suitable additives for foamed plastic
include graphite, for instance Neopor (Trade Mark), which is a
graphite-containing expanded polystyrene maufactured by BASF. The
first panel may contain two or more layers of foamed plastic
thereby forming a composite form. The thickness of the first panel
will be determined by the particular insulation value which is
required for the particular building being constructed. Suitably
the first panel may have a thermal conductivity below 0.045 W/mK.
Generally the thermal conductivity can be any value below this and
may be as low can be measured. It is possible that the thermal
conductivity may be as low as 0.005 W/mK. Typically the thermal
conductivity of the first panel may be in the range of 0.010 and
0.040 W/mK often within the range 0.020 and 0.040 W/mK.
[0035] The second panel may be constructed from any material that
provides the right characteristics for use in the wall form units
and system. It should be rigid and adapted to retain the
construction material such as concrete. Furthermore, it should
desirably possess a thermal conductivity of least 0.1 W/mK (Watts
per metre Kelvin) at least in the direction of the thickness of the
panel, and preferably at least 0.2 W/mK. In some cases the thermal
conductivity of the second panel may be at least 0.25 W/mK, at
least 0.3 W/mK, at least 0.4 W/mK and preferably at least 0.5 W/mK
and more preferably at least 1.0 W/mK. There is no upper limit to
the thermal conductivity provided that the other properties such as
rigidity and strength are not compromised. The thermal conductivity
may be up to 100 W/mK.
[0036] The second panel may be constructed from any suitable metal
in the form of a metal sheet for instance. Typically this may be
aluminium or copper having thermal conductivities of 200 W/mK and
380 W/mK respectively. However, it is preferred that the second
panel is constructed from suitable building materials which have
been adapted to improve the thermal conductivity.
[0037] Second panels potentially include concrete panels or blocks,
stone or marble panels or boards comprising cement, such as
Portland cement or magnesia cement e.g. fibre board or particle
board. Plasterboard may be used if it is made sufficiently durable
such that it is not damaged during the construction process.
Standard plasterboards are generally not suitable for this
application.
[0038] Preferably the second panel comprises a combination of at
least two components comprising a first component which is selected
from inorganic binders, a polymer and a polymer-based compound and
a second component selected from thermally conducting particles,
filaments or mesh which are distributed throughout the first
component.
[0039] Preferred first components of the second panel include
inorganic hydraulic binders such as are found in cement-based
boards, for instance Portland cement, particularly magnesia cement
boards such as those based on magnesium oxysulphate, magnesium
oxychloride and magnesium phosphate. Hydraulic inorganic binders
are for instance inorganic materials that react with water to form
solid matrices. Other examples include magnesium oxide, calcium
oxide, calcium hydroxide/pozzolana mixtures, calcium aluminate
cements, gypsum plaster etc. Non-hydraulic inorganic binders may
also be used as the first component of the second panel. Such
binders harden by completely or partially drying out, and include
calcium hydroxide, calcium carbonate, clay, magnesium hydroxide
etc. Blends may also be used and it is preferred that an inorganic
binder contains at least one hydraulic binder.
[0040] The second component of the second panel will include
materials that have high thermal conductivity. In order to provide
the second panel with sufficient thermal conductivity the second
component materials will desirably have thermal conductivities of
at least 0.1 W/mK and preferably at least 0.2 W/mK. It is
particularly preferred that the second component materials possess
thermal conductivities in excess of 1.0 W/mK and especially in
excess of 2.0 W/mK. there is no maximum limit of the thermal
conductivity of the second component and this may be as high 200 or
even 500 W/mK.
[0041] Preferably, the second component of the second panel can be
any of the material is selected from the group consisting of
graphite, alumina particles, silica sand, fine gravel or stone
particles, metallic fibres, metallic mesh and metallic particles.
Suitable metals include iron, copper, aluminium or metal alloys
such as steel or brass. Other metals or metal alloys may be used
such as lead, tin, bronze, silver etc.
[0042] The second component of the second panel may be in the form
of particles, fibres or other structure, such as mesh. Typically
the particles may be relatively fine having weight average particle
size diameters of below 1 mm, especially below 0.1 mm and for
instance as low as 0.01 mm or below. Alternatively the particles
may be relatively coarse having weight average particle size
diameters of at least 1 mm and even at least 2 mm, for instance up
to 5 mm or even up to 10 mm or 20 mm or more. The fibres may have
cross-sectional diameters of between 0.01 mm and 1 mm or higher.
The lengths of the fibres may be relatively short, for instance
less than 5 mm or sometimes may be as much as 10 mm or 20 mm and
considerably longer if in the form of a wool, for instance steel
wool or steel mesh.
[0043] The second panel may comprise the first component in an
amount between 5 and 100% by weight of the two components (not
including any fillers or lining materials such as paper or scrim)
and the second component in the amount of between 0 and 95% by
weight of the panel. Typically the second component may be present
in the panel in an amount between 5 and 95% by weight whilst the
first component may be present in an amount of between 5 and 95% by
weight. In many systems the second component can be the major
component, for instance between 65 and 95% by weight, preferably
between 75 and 85% by weight and the first component can be between
5 and 35% by weight, preferably between 15 and 25% by weight.
Preferably the first component will form a matrix within the panel
throughout which the second component is distributed. Should the
second panel have high thermal conductivity, say >0.1 W/mK, then
a second component may not be necessary.
[0044] The second panel may be constructed from a material which
contains partial aeration, for instance pumice, provided that the
aeration does not compromise the thermal conductivity and ability
to contain the pourable, curable construction material. Generally
the material used to form the second panel desirably should not
contain significant amounts of air voids, for instance by aeration
as this may tend to yield lower thermal conductivity. Desirably the
second panel should be as dense as it is practicable within the
normal constraints of panel manufacturing, construction of the
building and use of the building. Desirably the second panel has a
density of at least 100 kg/m.sup.3 and preferably at least 300
kg/m.sup.3 and more preferably at least 700 kg/m.sup.3. Especially
preferred materials tend to have densities of at least 1000
kg/m.sup.3 and often as much as 1500 kg/m.sup.3. Nevertheless, the
density may be significantly higher, for instance up to 1750
kg/m.sup.3 or even up to 2400 kg/m.sup.3 or more.
[0045] An example of a second panel is one formed from Portland
cement or magnesia cement as the first component comprising
particles of sand or fine aggregate as the second component which
is distributed throughout the Portland cement or magnesia cement.
Suitably the sand or fine aggregate will form between 65 and 95% of
the total weight of the second panel the remainder being the
magnesia cement. Preferably the sand or fine aggregate will form
between 75 and 85% of the total weight of the second panel and the
magnesia cement will form between 15 and 25% by total weight.
[0046] The second panel may also contain other components such as
fillers or strengthening fibres. Such fillers may for instance be
included where the second panel is based on a hydraulic inorganic
binder such as magnesia cement. Typically this may include wood
particles or fibres, synthetic fibres glass, basalt or carbon
fibres or carbon particles. However, the aim must be to maximise
the overall thermal conductivity of the second panel, and the
addition of fillers, fibres etc must be considered carefully with
this aim in mind. A balance must be found between achieving a
suitably high thermal conductivity and achieving requirements such
as strength, appearance, cost etc.
[0047] In a preferred form of the invention the second panel may
contain phase change material (PCM). This feature will allow
further temperature regulation of rooms within the building.
[0048] Suitable phase change materials may be organic, water
insoluble materials that undergo solid-liquid/liquid-solid phase
changes at useful temperatures (typically between 0 and 80.degree.
C.). Generally the enthalpy of phase change (latent heat of fusion
and crystallization) is high. Suitable organic phase change
materials exhibit a high enthalpy of phase change, typically >50
kJ/kg, preferably >100 kJ/kg and most preferably >150 kJ/kg
when determined by Differential Scanning Calorimetry (DSC).
[0049] Suitable organic phase change materials include (but are not
limited to) substantially water insoluble fatty alcohols, glycols,
ethers, fatty acids, amides, fatty acid esters, linear
hydrocarbons, branched hydrocarbons, cyclic hydrocarbons,
halogenated hydrocarbons and mixtures of these materials. Alkanes
(often referred to as paraffins), esters and alcohols are
particularly preferred. Alkanes are preferably substantially
n-alkanes that are most often commercially available as mixtures of
substances of different chain lengths, with the major component,
which can be determined by gas chromatography, between C.sub.10 and
C.sub.50, usually between C.sub.12 and C.sub.32. Examples of the
major component of an alkane organic phase change materials include
n-octacosane, n-docosane, n-eicosane, n-octadecane, n-heptadecane,
n-hexadecane, n-pentadecane and n-tetradecane. Suitable ester
organic phase change materials comprise of one or more
C.sub.1-C.sub.10 alkyl esters of C.sub.10-C.sub.24 fatty acids,
particularly methyl esters where the major component is methyl
behenate, methyl arachidate, methyl stearate, methyl palmitate,
methyl myristate or methyl laurate. Suitable alcohol organic phase
change materials include one or more alcohols where the major
component is, for example, n-decanol, n-dodecanol, n-tetradecanol,
n-hexadecanol, and n-octadecanol.
[0050] It is also possible to include a halogenated hydrocarbon
along with the main organic phase change material to act as a fire
retardant.
[0051] Organic phase change materials are substantially water
insoluble, as this is necessary for preparing particulate forms of
the organic phase change material, for instance in emulsion form or
encapsulated form.
[0052] Organic phase change materials are utilized in the invention
in a particulate form, by which is meant either in emulsified or
encapsulated form. For reasons discussed in more detail below, the
particle size of phase change material particles should not be too
large. Typically the phase change material particles are as small
as possible within certain limitations. This is discussed in more
detail below when considering the phase change material form, for
instance in emulsion or encapsulated form.
[0053] In order to provide the composition of the invention where
the organic phase change material is not encapsulated it is
generally desirable to provide the organic phase change material in
the form of an emulsion. Suitable emulsions comprise of a disperse
phase of organic phase change material stabilized in an aqueous
continuous phase, hence it is a type of oil-in-water or O/W
emulsion. The term "emulsion" is often applied to liquid-in-liquid
two phase systems. In this invention we allow the term "emulsion"
to embrace both the liquid-in-liquid and solid-in-liquid systems
depending on whether the particles of phase change material are
liquid (molten) or solid (crystallized). Hence the term
"particles", when referring to the organic phase change material,
also embraces both the liquid and solid form. In a suitable
emulsion, monomeric and/or polymeric surfactant(s) is/are used to
facilitate emulsification of the organic phase change material and
stabilize the particles in the aqueous continuous phase.
[0054] The particle size of an emulsion is generally limited to a
fairly narrow range. Large oversized particles, especially very
coarse particles, should be avoided since they tend to be more
unstable and more prone to coalescence and hence phase separation.
Thus, for practical reasons, the particle size of the organic phase
change material in an emulsion form is typically between 0.05 .mu.m
and 50 .mu.m, often between 0.1 .mu.m and 20 .mu.m and more often
between 0.5 .mu.m and 10 .mu.m (expressed as volume mean diameter
as determined, for example, by a Sympatec particle-size analyzer).
Therefore this definition includes emulsions described as
microemulsions and nanoemulsions.
[0055] Preferably the emulsions will contain at least 20% w/w
particles of organic phase change material and more preferably this
will be at least 40% w/w. The emulsion may contain up to 75 or 80%
w/w, although usually not more than 60 or 65% w/w.
[0056] Normally the emulsions should be suitably stable in that
they should not phase separate after several hours in static
storage; preferably they will be stable for at least 7 days and
most preferably for at least 30 days. Often the emulsions are
stable for several weeks or months and even up to one year or more.
Although there may be a tendency for particles to migrate towards
the surface of the storage container (an effect known as
"creaming"), a good emulsion will not destabilize to form a
substantial layer of coalesced phase change material and stirring
will substantially rehomogenize the creamed particles.
[0057] Suitable emulsions may be prepared by conventional methods
such as those described in the book "Emulsion Science" by Philip
Sherman. A useful guide to monomeric surfactant (emulsifier)
selection is given in a publication by ICI entitled "The HLB
System". Numerous other literature articles describe the
preparation of stable emulsions, including the selection and amount
of monomeric and/or polymeric surfactant(s) to be used.
[0058] Note that it is generally preferred to prepare the emulsion
using the liquid form of the organic phase change material i.e. in
a molten state. Organic phase change materials that contain an
additive such as a halogenated paraffin, organic nucleating agent,
oil soluble surfactant etc should also be in a fully liquid state,
ideally. It is preferable to maintain the organic phase change
material (including optional additives) in a liquid state during
the formation of the emulsion, which usually involves maintaining
the temperature of the organic phase change material (including
optional additives) above the temperature where wax crystals may
form. The formation of an emulsion involves the combination of a
disperse phase comprising the organic phase change material to an
aqueous phase and it is sometimes necessary to control the
temperature of the aqueous phase prior to and/or during the
addition of the organic phase change material. This is to avoid
cooling the disperse phase to a point where problematical
crystallization can occur.
[0059] Typically encapsulated organic phase change materials
comprise the organic phase change material and optional additives
such as a halogenated paraffin or a nucleating agent which is
surrounded by a shell that is impermeable to the phase change
material. Unlike free (unconstrained) particles of organic phase
change material, capsule particles remain as solid particles even
when the organic phase change material in the core of the capsules
is in its higher energy molten state. In capsule form the organic
phase change material is completely surrounded and entrapped by the
shell and is protected against contamination. When the shell is
robust, the organic phase change material is more securely
contained and less likely to escape from the capsules and
compositions comprising capsules. For this reason it is preferred
to use capsules in this invention, particularly capsules that are
robust. Details of the robust character of the capsules are
provided below.
[0060] Since encapsulated organic phase change materials tend to be
stable, solid entities, they can be provided in a broader range of
particle sizes than would be possible for the aforementioned
emulsified organic phase change materials. It is possible to use
capsules in this invention with mean primary particle size of
between 0.1 .mu.m and 1 mm. Generally, it is preferred to use
smaller capsule particle sizes in this invention for a number of
reasons. Smaller primary capsules tend to be more durable leading
to inventive compositions which do not readily release organic
phase change material. Due to their greater surface/volume ratio,
smaller particle sizes are expected to give inventive compositions
which more readily transfer heat to/from the particles of organic
phase change material. It is generally possible for smaller
capsules to be more uniformly distributed throughout the second
panel.
[0061] Capsules may conveniently be used in the form of an aqueous
dispersion or dry powder.
[0062] Suitable aqueous dispersions typically comprise 30 to 60%
w/w, most preferably 40 to 50% w/w microcapsules. When provided as
an aqueous dispersion, the particle size of capsules of organic
phase change material should be carefully considered. In addition
to the benefits of smaller capsules discussed earlier, dispersions
of smaller capsules tend to exhibit the favourable property of
better stability (reduced capsule creaming or settling) and the
unfavourable property of increased viscosity compared to a
dispersion of larger sized capsules at an equivalent concentration.
It is also generally more difficult to prepare suitable capsules
with very small particle sizes and/or the process required is more
costly due to the extra processing that is required and/or the use
of more specialized equipment. A balance must be found between
these advantages and disadvantages and a volume mean diameter (VMD)
of capsules (when in the form of an aqueous dispersion) of between
0.2 .mu.m and 20 .mu.m is usually chosen. Preferably the VMD of the
capsules in an aqueous dispersion is between 0.7 .mu.m and 10 .mu.m
and more preferably between 1 .mu.m and 5 .mu.m. VMD is determined
by a Sympatec Helos particle size analyzer or another technique
found to give results for microcapsules that are in very good
agreement with the results from a Sympatec Helos analyzer.
[0063] Capsules in a dry form may also be used in this invention.
Such capsules may be obtained when an aqueous dispersion or
suspension of capsules is subjected to a water removal step, which
may include spray-drying, air-drying, filtration or centrifugation.
It is also possible to partially remove the water to produce a
paste or cake form of the capsules. Spray-drying is particularly
preferred when producing essentially dry products from a dispersion
of microcapsules up to 10 .mu.m in VMD. Preferably the
particle-size of the capsules to be spray-dried is 1 .mu.m to 5
.mu.m. Spray-dried particles of organic phase change material
comprise of 1 or more primary particles (microcapsules), and often
several primary particles in an agglomerated form. The VMD of the
spray-dried particles is generally 5 .mu.m to 200 .mu.m, preferably
10 .mu.m to 100 .mu.m and more preferably 20 .mu.m to 80 .mu.m.
This range balances the advantages of small particle sizes with the
need to avoid dust and associated respiratory hazards.
[0064] It is preferable to use the aqueous dispersion form of
capsules in this invention as this usually provides the preferred
smaller capsule particle sizes and, as the water removal step
needed for the dry product is avoided, at a lower cost. It is noted
that typical microencapsulation processes provide an aqueous
capsule dispersion as a product of the process.
[0065] The encapsulation process results in capsules with a
substantially core-shell configuration. The core comprises of
organic phase change material and the shell comprises of
encapsulating polymeric material. Usually the capsules are
substantially spherical. Preferably the shell is durable such that
the organic phase change material is protected from contamination
and cannot easily escape from the capsules. Thermogravimetric
analysis (TGA) provides an indication of the robustness of the
capsules. "Half Height" is the temperature at which 50% of the
total mass of dry (water-free) capsules is lost as a fixed mass of
dry capsules is heated at a constant rate. In this analysis method
mass may be lost due to organic phase change material escaping as
vapour permeating through the shell and/or due to rupturing of the
shell. Particularly suitable microcapsules of organic phase change
material (in the 1 .mu.m to 5 .mu.m mean particle size range) have
a Half Height value greater than 200.degree. C. or 250.degree. C.,
preferably greater than 300.degree. C. and more preferably greater
than 350.degree. C., when TGA is carried out under a nitogen
atmosphere using a Perkin-Elmer Pyris 1 at a rate of 20.degree. C.
per minute using typically 5 to 50 mg of dry sample. The dry sample
is obtained by adding a quantity of the dispersion product (usually
at 45% w/w solids content) to the sample pan of the analyzer and
then holding the temperature at 110.degree. C. to remove the water
(the dry state has been reached when stable readings are obtained
at 110.degree. C.). The analysis then proceeds by increasing the
temperature at a rate of 20.degree. C./minute.
[0066] Microcapsule products in powder form, obtained from a
spray-drying process as described earlier, for example, may be
analyzed in the same way. In this case the drying step is usually
very short as the powder is essentially dry.
[0067] Capsules may be formed by any convenient encapsulation
process suitable for preparing capsules of the correct
configuration and size. Various methods for making capsules have
been proposed in the literature. Processes involving the entrapment
of active ingredients in a matrix are described in general for
instance in EP-A-356,240, EP-A-356,239, U.S. Pat. No. 5,744,152 and
WO 97/24178. Typical techniques for forming a polymer shell around
a core are described in, for instance, GB 1,275,712, 1,475,229 and
1,507,739, DE 3,545,803 and U.S. Pat. No. 3,591,090.
[0068] The phase change material may be applied to one or more
surfaces of the formed second panel, preferably to the surface
facing the interior of the building. More preferably, however, the
phase change material is incorporated into the matrix of the second
panel during its manufacture. In fact the major component, e.g.
first component, of the second panel, preferably magnesia cement,
will desirably form a matrix in which the phase change material is
surrounded. More preferably both first component, preferably
magnesia cement, and the second component, preferably sand or fine
aggregate, will surround the phase change material. In particular
the phase change material may be uniformly distributed throughout
both the first component, e.g. magnesia cement, and second
component, e.g. sand or fine aggregate of the second panel.
[0069] The phase change material may be incorporated during the
production of the second panel or applied to the surface of the
formed second panel in which the phase change material may be in
the form of a dispersion or slurry in a continuous phase liquid.
Typically this may be a dispersion or slurry in water or for
instance in the form of an aqueous emulsion. Preferably the phase
change material is microencapsulated and is applied as an aqueous
dispersion. Alternatively the phase change material may be applied
in the form of dried microcapsules.
[0070] The second panel may contain flame retardant additives and
this may include inorganic salts or other inorganic compounds such
as magnesium hydroxide, aluminium hydroxide or borates.
[0071] The thickness of the second panel may be between 5 and 50
mm, preferably between 5 and 30 mm, more preferably between 10 and
20 mm.
[0072] The first and second panels may be fitted with suitable
anchor points for the internal ties. The tie anchors may be cast
into the foamed plastic during manufacture. Where the first panel
is constructed from some other material other means for securing
the anchor points may be more appropriate, for instance screws or
other standard fixing means.
[0073] The ties may be any conventional ties used in ICFs or other
wall form units are described in the prior art, for instance as
referred to herein. Typically the ties can be constructed from
metal or plastic. Where the ICFs are not based on the "flat pack"
system but form an integrated block, the ties may be constructed of
foamed plastic. The ties should desirably incorporate a spacer
member which maintains the predetermined distance of the first and
second panels. Typically the ties and spacer member will form an
integrated entity and desirably will be constructed from metal or
plastic, or foamed plastic as given above. It may be desirable to
integrate the ties with the first and second panels to form an
integrated block. Tie anchors may be cast into the panels,
particularly the first panel. The first and/or second panel may
contain slots where the ends of the ties are inserted and secured.
In this case the ties may be permanently connected to one panel and
connected to the other panel by inserting the free end of the ties
into slots in the other panel. Alternatively the ties may be fitted
into slots in both panels. Two or more types of ties may be
used.
[0074] According to one aspect of the present invention the wall
form unit (e.g. ICF) is assembled by interconnecting a multiplicity
of first panels together and a multiplicity of second panels
together, thus formed assembly of first panels and thus formed
assembly of second panels being maintained in a predetermined
distance by a suitable tie assembly. The hollow section formed
between the assembly of first panels and the assembly of second
panels, hereafter referred to as the cavity, may be between 50 and
500 mm in spatial distance between the two assemblies. Preferably
the cavity may have an interspatial distance of between 100 and 220
mm. Typical cavity interspatial distances can for instance be 102
mm, 158 mm, and 203 mm depending upon the building structure
required. Other pre-formed sections, such as corners, may also be
made according to this invention.
[0075] The above described embodiments of the invention are
intended to be examples of the present invention and alterations
and modifications may be affected there to, by those skilled in the
art, without departing from the scope of the invention which is
specified in the claims.
[0076] FIG. 1 shows a wall section according to the present
invention having a first panel (1) of a thermally insulating
material on the exterior side of the wall section; a metal rebar
(2) for wall supporting strength; a tie (3) for maintaining the
first and second panels spaced apart in predetermined relation; a
corner post (4); a second panel (5) of thermally conducting
material located on the interior side of the wall section; and
concrete (6) as a pourable, curable construction material.
* * * * *
References