U.S. patent application number 10/090385 was filed with the patent office on 2002-12-05 for composite product and method of manufacture.
Invention is credited to Cottier, John Sydney, Lyons, Robert, Naji, Basil.
Application Number | 20020179219 10/090385 |
Document ID | / |
Family ID | 27507501 |
Filed Date | 2002-12-05 |
United States Patent
Application |
20020179219 |
Kind Code |
A1 |
Naji, Basil ; et
al. |
December 5, 2002 |
Composite product and method of manufacture
Abstract
A method of manufacturing a composite product comprising
providing a substrate layer and a slurry formulation including a
hydraulic binder and dewatering agent. The slurry is then applied
to the substrate layer to form a functional layer and the
functional layer dewatered through the substrate layer. The
application of the slurry to form the functional layer and
dewatering steps can be repeated to build up a laminated composite
product. Functional additives may be included in each layer to
provide desired properties to that layer and indeed to the
subsequent composite product.
Inventors: |
Naji, Basil; (Toongabbie,
AU) ; Cottier, John Sydney; (Oatley, AU) ;
Lyons, Robert; (Alta Loma, CA) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
620 NEWPORT CENTER DRIVE
SIXTEENTH FLOOR
NEWPORT BEACH
CA
92660
US
|
Family ID: |
27507501 |
Appl. No.: |
10/090385 |
Filed: |
March 4, 2002 |
Current U.S.
Class: |
156/45 ;
156/41 |
Current CPC
Class: |
E04F 13/02 20130101;
C04B 18/08 20130101; Y10T 428/31504 20150401; Y10T 428/25 20150115;
Y10T 442/10 20150401; Y10T 428/265 20150115; B28B 7/46 20130101;
E04F 15/12 20130101; B28B 1/522 20130101; Y10S 106/01 20130101;
C04B 28/02 20130101; E04C 2/06 20130101; Y10T 428/249932 20150401;
C04B 2111/00612 20130101; Y10T 428/31667 20150401; Y10T 428/249986
20150401; C04B 2111/00482 20130101; Y10T 428/249972 20150401; Y02W
30/91 20150501; Y10T 428/249968 20150401; C04B 28/02 20130101; C04B
18/08 20130101; C04B 18/08 20130101; C04B 18/08 20130101; C04B
20/008 20130101 |
Class at
Publication: |
156/45 ;
156/41 |
International
Class: |
B32B 013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 2, 2001 |
AU |
PR3474 |
Mar 2, 2001 |
AU |
PR3475 |
Mar 2, 2001 |
AU |
PR3476 |
Mar 2, 2001 |
AU |
PR3477 |
Mar 2, 2001 |
AU |
PR3478 |
Claims
What is claimed is:
1. A method of manufacturing a composite product, comprising: (i)
providing a substrate layer; (ii) providing a slurry formulation
including an hydraulic binder and dewatering agent; (iii) applying
said slurry to said substrate layer to form a functional layer; and
(iv) dewatering the functional layer, wherein the quantity of
dewatering agent is sufficient to maintain porosity and thereby
permit de-watering of the functional layer through the substrate
layer.
2. A method according to claim 1, comprising repeating steps (ii)
through (iv), wherein the quantity of dewatering agent is
sufficient to maintain porosity and thereby permit de-watering of
each functional layer through the substrate layer and any
additional functional layer.
3. A method according to claim 1, wherein the functional layer
includes one or more functional additives to provide desired
properties to that layer.
4. A method according to claim 1, wherein the substrate layer is a
fibre reinforced base material.
5. A method according to claim 1, wherein the substrate layer is a
reinforced cementitious product.
6. A method according to claim 1, wherein functional layers are
added to both sides of the substrate layer.
7. A method according to claim 1, wherein functional layers are
added to one side of the substrate layer.
8. A method according to claim 1, wherein the functional layer is
covered by a reinforcing layer.
9. A method according to claim 1, wherein the reinforcing layer
comprises fibre mesh or netting.
10. A method according to claim 1, wherein the reinforcing layer is
a fibre reinforced cementitious layer.
11. A method according to claim 1, wherein the composite product
comprises outer layers provided by fibre reinforced cementitious
layers with one or more functional layers positioned
therebetween.
12. A method according to claim 11, wherein the functional layers
have a low fibre content relative to the fibre reinforced
cementitious layers.
13. A method according to claim 1, wherein additives and/or fillers
are incorporated in the functional layer to provide desired
acoustic properties, thermal or fire performance, density
modification, cost or production efficiency, compressive or tensile
strength, water permeability, density or aesthetic properties to
the composite product.
14. A method according to claim 2, wherein the dewatering agent is
provided in a sufficient quantity to maintain porosity in the
functional layers and the substrate layer during dewatering.
15. A method according to claim 1, wherein the dewatering agent is
a particulate material.
16. A method according to claim 1, wherein the dewatering agent is
selected from the group consisting of fly ash, alumina trihydrate,
silica flour, cenospheres and mixtures thereof.
17. A method according to claim 1, wherein the product is cured by
air curing, steam curing or hydrothermally cured in an
autoclave.
18. A method according to claim 1, wherein the product is a
cementitious building board or product or gypsum building
board.
19. A method according to claim 1, wherein the thickness of the
functional layer on the product is between about 0.1 and 10 mm.
20. A method according to claim 1, wherein the hydraulic binder
used in the slurry formulation is selected from the group
consisting of white, grey or pigmented cements, hydraulic limes and
mixtures thereof.
21. A method according to claim 1, wherein the binder in the
formulation is between about 10 and 50 wt % based on total dry
ingredients.
22. A method according to claim 1, wherein fly ash is the
dewatering agent.
23. A method according to claim 22, wherein the dewatering agent
comprises: i) about 10 to 60% of the formulation based on total dry
ingredients of a first fly ash component having a particle diameter
between about 1 and 100 microns; and ii) about 5 to 30 wt % of the
formulation based on total dry ingredients of a second fly ash
component having a maximum particle size diameter of around 10
microns.
24. A method according to claim 1, wherein the dewatering agent
includes a coarse fraction fly ash having a particle size diameter
greater than about 100 microns.
25. A method according to claim 1, wherein the functional layer
includes additives to improve the properties of the substrate layer
such that upon dewatering of the functional layer, the substrate
layer is thus treated with said additive.
26. A method according to claim 1, wherein the slurry formulation
is applied to the substrate layer by means of splattering.
Description
PRIORITY CLAIM
[0001] This application claims priority from the following
Australian provisional patent applications, the full contents of
which are hereby incorporated by cross-reference.
1 Application No Title Date Filed PR3474 A Composite Product 2
March 2001 PR3475 Spattering Apparatus 2 March 2001 PR3476 Additive
for a Dewaterable Slurry 2 March 2001 PR3477 A Method and Apparatus
for Forming a 2 March 2001 Laminated Sheet Material by Spattering
PR3478 Coatings for Building Products 2 March 2001
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to composites and
particularly, but not limited to, fibre reinforced building
composites, and methods of manufacturing the same.
[0004] 2. Description of the Related Art
[0005] Any discussion of the prior art throughout the specification
should in no way be considered as an admission that such prior art
is widely known or forms part of common general knowledge in the
field.
[0006] Fibre reinforced cement (FRC) is an extremely popular
building product.
[0007] The applicant along with other various parties have
developed a variety of techniques for producing fibre reinforced
cement building products and tailoring those FRC products to the
particular environment of use.
[0008] There are still, however, certain limitations with regard to
FRC products. They have limited acoustic, thermal and fire
retardant properties. They can exhibit limited workability and
generally lie in the medium density range (around 1300 kg/m.sup.3)
or higher (compressed densities of around 1700 kg/m.sup.3).
[0009] Generally, the properties of fibre cement are altered by
addition of other materials eg different fibres, fillers etc or
altered with different production techniques. Such alterations to
the FRC formulation, however, can be expensive to develop in order
to ensure no detrimental side effects arise from such new
formulations. Alterations in production methods or equipment are
also expensive and time consuming to develop. Such techniques also
do not provide for true "tailoring" of the FRC product. It is, of
course, inappropriate to shut down an entire production line, for
example, to produce a small batch of FRC product tailored to a
specific use.
[0010] It is an object of the present invention to overcome or
ameliorate at least one of the disadvantages of the prior art, or
to provide a useful alternative.
SUMMARY OF THE INVENTION
[0011] In a broad aspect, the present invention provides a
composite product comprising a substrate layer and one or more
functional layers applied thereto, each functional layer including
a mixture of hydraulic binder, dewatering agent wherein the
quantity of dewatering agent is sufficient to permit de-watering of
each functional layer through the substrate layer and any
additional functional layer.
[0012] In a second aspect, the present invention provides a method
of manufacturing a composite product comprising:
[0013] (i) providing a substrate layer,
[0014] (ii) providing a slurry formulation including an hydraulic
binder and dewatering agent,
[0015] (iii) applying said slurry to said substrate layer to form a
functional layer,
[0016] (iv) dewatering the functional layer, and
[0017] (v) optionally repeating steps (ii) through (iv), wherein
the quantity of dewatering agent is sufficient to maintain porosity
and thereby permit de-watering of each functional layer through the
substrate layer and any additional functional layer.
[0018] Preferably, the substrate layer is a fibre reinforced base
material such as fibre reinforced cement. This substrate layer
provides a structural base on which additional functional layers
may be added.
[0019] The functional layers may be added to both sides of the
substrate layer but most preferably are added to one side which
generally expose one side of the building board during production.
Such a technique allows the aforementioned method to be applied to
current FRC production techniques such as Hatschek.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] The present applicants have developed a process for
manufacture of a composite article to virtually any desired
specification or use. To explain, the present inventive composite
and method starts with a simple water permeable substrate layer
such as conventional fibre reinforced building board. To this base
layer are added one or more functional layers, each functional
layer being specifically tailored to provide the desired
functionality. For example, if it is desired to provide an
insulating layer, the slurry formulation from which the functional
layer is formed can include insulating materials such as rubber
crumbs, vermiculite, perlite, gypsum, etc.
[0021] Similarly, water permeability may be decreased by including
water resistant polymers eg silanes, siloxane blends etc or
pozzalanic materials such as silica fume, metakaoline, ultrafine
fly ash etc.
[0022] Density modification of the functional layer can be
accomplished by addition of suitable light weight materials such as
cenospheres (ceramic hollow spheres), expanded polystyrene,
vermiculite, perlite etc.
[0023] The inventive process enables various functional layers to
be integrated into a single composite by appropriate slurry
modification.
[0024] In a preferred embodiment, each functional layer has a
reinforcing layer positioned therebetween. The reinforcing layer
may comprise fibre mesh or netting, and serves to improve the
strength and durability of the composite product.
[0025] In some instances, the reinforcing layer may comprise a thin
fibre reinforced cementitious layer similar for instance to the
base material. This provides for more efficient utilisation of such
fibre reinforced layers, similar to sandwich composite technology.
It will be appreciated by a person skilled in the art, that there
are areas of a composite which require less fibre reinforcement ie
the core. Such a core area can be formed as the aforementioned
functional layer with low fibre reinforcement. Areas which require
high fibre reinforcement due to high tensile strength ie surface or
skin areas, can be covered by a fibre reinforced cementitious
layer. The thus formed fibre reinforced layers act as sandwich
skins with a de-watered slurry functional layer acting as a
sandwich core.
[0026] As a result, the described composite provides significant
advantages over monolithic fibre reinforced composites. Firstly, by
the aforementioned composite action, fibres can be positioned in
areas where they are most required. This will, of course, lead to a
reduction in the fibre reinforced volume of the product.
[0027] Secondly, such a reduced fibre volume will lead to an
improvement in non-combustibility and thermal insulation
performance of the composite. Production of a non-combustible
composite has, in the past, been difficult to achieve due the high
cost of non-combustible fibres and specialised processes required
for their use.
[0028] Further, one of the most important advantages arising from
preferred embodiments of the present invention is the ability to
concentrate a particular functionality into a single layer. To
explain, in large monolithic structural layers, particularly fibre
reinforced cement building products, any adjustments to the
functional or structural aspects of the product ,au be diluted or
diminished or unevenly spread throughout the product. There is also
the possibility of adverse side reactions occurring during
production of such a monolithic product which may diminish the
structural or functional attributes required. With the present
invention, on the other hand, it is possible to concentrate or
target specific functional or structural attributes within a single
functional layer thereby assuring the attribute is provided to the
resultant composite product.
[0029] Indeed, various optional additives and filler can be
incorporated for specific purposes, ie acoustic, thermal or fire
performance, density modification, cost or production
efficiency.
[0030] A top or finish coating layer can also be provided for the
composite product by a fibre reinforced cementitious layer, a
material similar or identical to the functional layer or any other
product. In one particularly preferred embodiment, the top or
finishing coating can be primarily an "aesthetic" layer of, say,
ultrafine particle size or made from a sandable material to smooth
the exterior surface of the composite product and thereby provide a
finish/paint ready surface.
[0031] Unless the context clearly requires otherwise, throughout
the description and the claims, the words `comprise`, `comprising`,
and the like are to be construed in an inclusive sense as opposed
to an exclusive or exhaustive sense; that is to say, in the sense
of "including, but not limited to".
[0032] The dewatering agent serves to maintain sufficient porosity
in the slurry and product to be coated to permit dewatering of the
slurry through the product to be coated. Preferably, the dewatering
agent is a particulate material such as fly ash, alumina
trihydrate, silica flour, cenospheres (ceramic hollow spheres) or
similar.
[0033] Fly ash is particularly preferred as it permits dewatering
of the slurry within a few minutes. Other particulate dewatering
agents such as alumina trihydrate or silica flour may also be used,
however, they increase the time required for dewatering of the
slurry through the product to be coated.
[0034] In a preferred embodiment, the slurry applied to the product
to be coated has a high water content. Preferably, the water
content can be up to about 50%. This is in contrast to previous
cementitious formulations which generally have a very high solids
content.
[0035] By combining the various components of the formulation
described above, a self levelling dewaterable slurry is obtained
which can be applied to the substrate layer, dewatered through the
substrate layer and thereby provide a uniform coating over this
substrate layer.
[0036] Normally, after application of the coating, the resultant
product would be normally cured, steam cured or hydrothermally
cured, ie autoclaved, and if required, sanded to a smooth flat
finish.
[0037] The substrate layer to which the functional layers can be
applied is virtually limitless provided the slurry can be dewatered
through the substrate layer. Cementitious and gypsum building
boards are typical examples of suitable building products on which
the coating can be applied.
[0038] The thickness of the functional layers would range from
around 0.1 to 10 mm, preferably about 0.5 to 5 mm and most
preferably about 1 to 3 mm.
[0039] After optional sanding, the layer may have a depth of around
0.05 to 5 mm, preferably about 1 to 2 mm and most preferably about
0.5 to 1 mm. The thus produced composite is comparable in its
workability to monolithic (single layer) composites. It can be
flexed, cut, drilled and fixed by nails etc to a frame without
surface cracking or chipping.
[0040] The applicants have found an extremely good interlaminer
bond and compatibility between the dewatered slurry layer and base
layer resulting in excellent composite action, compatibility and
resistance to delamination.
[0041] The term `hydraulic binder` as used throughout the
specification refers to a pulverised material in the solid, dry
state which, when mixed with water, yields plastic mixtures that
are able to set and harden, for example a cement. Included within
the definition are white, grey or pigmented cements and hydraulic
limes.
[0042] The term `cement` includes hydraulic and alite cements such
as portland cement, blended cements such as portland cement blended
with fly ash, blast-furnace slag, pozzalans and the like and
mixtures thereof, masonry cement, oil well cement, natural cement,
alumina cement, expansive cements and the like, or mixtures
thereof.
[0043] The quantity of binder in the formulation is preferably
between about 10 to 50 wt % based on the total dry ingredients,
more preferably about 15 to 40 wt % and most preferably about 20 to
30 wt %.
[0044] The fly ash used in the preferred embodiments provides a
number of advantages including, particularly, as an aid to
dewatering of the slurry as defined above.
[0045] The term `fly ash` as used herein refers to a solid powder
having a chemical composition similar to or the same as the
composition of material that is produced during combustion of
powdered coal, ie about 25 to 60 wt % silica, about 10 to 30 wt %
Al.sub.2O.sub.3, about 5 to 25 wt % Fe.sub.2O.sub.3, about 0 to 20
wt % CaO and about 0 to 5 wt % MgO.
[0046] In another preferred embodiment, the dewatering agent may
include a coarse fraction fly ash which is greater than about 100
microns. This coarse fraction fly ash includes bottom ash or
similar products from coal combustion. There is an advantage to
using these products over the aforementioned particle size fly ash
since it is cheaper. Of course, as will be clear to persons skilled
in the art, some reformulation of the slurry may be required to
provide a suitable coating and appropriate dewatering
characteristics when the dewatering agent is such a coarse fraction
fly ash.
[0047] Fly ash particles are typically spherical and range in
diameter from about 1 to 100 microns. In a preferred embodiment,
the fly ash comprises two components. A first `larger` size
particles of fly ash with preferably about a 100 micron maximum
size. This size range of fly ash is used in the slurry to aid in
improving the dewatering characteristics of the slurry but also as
a moderately reactive pozzalan.
[0048] The second `smaller` fly ash size zone which preferably has
about a 10 micron maximum size also adds an improving dewatering
characteristic but is a more highly reactive pozzalan. This
`smaller` fly ash particle zone also improves the sanded surface
quality of the finish layer.
[0049] In a preferred embodiment, the first fly ash comprises about
10 to 60 wt % of the formulation based on total dry ingredients,
more preferably about 20 to 50 wt % and most preferably about 30 to
40 wt %.
[0050] The second fly ash component preferably provides about 5 to
30 wt % of the formulation based on total dry ingredients, more
preferably about 10 to 25 wt % and most preferably about 15 to
20%.
[0051] The functional layers may optionally contain other additives
such as fillers. Such fillers may also be used to improve the
dewatering characteristics of the slurry. For example, cenospheres
(hollow ceramic microspheres) diatomite, wollastonite, ground rice
hulls, ground perlite or the like, are particularly suitable for
this purpose.
[0052] These and other fillers may also be used to provide
additional benefits, for example calcium carbonates or alumina
hydrates improve sandability and flexibility of the coated layer
respectively. Silica flour improves hardness of the sanded surface
of the coating layer and the acoustic/thermal insulation properties
of the layer can be improved by including rubber particles,
vermiculite, perlite, shredded or expanded polystyrene or
gypsum.
[0053] The fillers preferably comprise about 5 to 30 wt % of the
formulation based on total dry ingredients, more preferably about
10 to 25 wt % and most preferably about 25 to 20 wt %.
[0054] The functional layers may also contain other organic
additives. Cement plasticising agents, for example, may be used to
alter the rheology of the slurry. Suitable cement plasticising
agents include melamine sulphonate formaldehyde condensates,
naphthalene sulphonate formaldehyde condensates, naphthalene
sulphonates, calcium lignosulphonates, sodium lignosulphonates,
saccharose, sodium gluconate, sulphonic acids, carbohydrates, amino
carboxylic acids, polyhydroxycarboxilic acids, sulphonated melomine
and the like.
[0055] The amount of cement plasticiser of course will depend upon
the fluidising ability of the particular plasticisers. Generally
the quantity of plasticiser will be in the range of about 0.3 to 3
wt % and more preferably about 0.5 to 2 wt % based on the total of
dry ingredients in the formulation.
[0056] Particularly preferred cement plasticisers are Melment F-10,
a melamine formaldehyde sodium bisulphate polymer dispersant
marketed by SKW-Trostburg in the form of a fine white powder.
Another suitable plasticiser is Neosyn, a condensed sodium salt of
sulphonated naphthalene formaldehyde available from Hodgson
Chemicals.
[0057] Another preferred component in the coating is a biopolymer
which acts to enhance the flowability, segregation resistance and
self levelling qualities of the cementitious slurry. Particularly
suitable bioplymers are xanathan gum and/or whelan gum, eg
KELCO-CRETE, K1C 376 manufactured by Monsanto.
[0058] Latex may also be included in the formulation to improve
adherence, elasticity, stability and impermeability of the
functional layers. The latex also improves flexibility of the
formed composite.
[0059] The latex may be selected from the group consisting of
acrylic latex, styrene latex, butadiene latex or mixtures thereof
and is provided preferably in an amount between about 0.5 to 20%,
more preferably about 1 to 15% and most preferably about 10% by
weight of cement (on polymer solids basis) solids.
[0060] Vinyl polymers may also be incorporated into the formulation
either in addition or as a substitute to the latex emulsions. Such
vinyl polymers or equivalent polymeric materials enhance adhesion,
resilience and flexural strength and abrasion resistance of the
functional layer.
[0061] Preferred vinyl polymers include polyvinyl acetate or a
copolymer vinyl acetate with another monomer such as ethylene. A
particularly preferred vinyl acetate resin is VINNAPAS LL5044
thermo plastic resin powder which contains a vinyl acetate-ethylene
copolymer available from Wacker. Such powdered vinyl polymer is
preferably provided in quantities similar to the latex emulsion
referred to above.
[0062] In addition to the above, conventional other additives such
as mineral oxides, hydroxides and clays, metal oxides and
hydroxides, fire retardants such as magnesite, thickeners, silica
fume or amorphous silica, water sealing agents, water reducing
agents, setting modifiers, hardeners, dispersants, foaming agents
or flocculating agents, water-proofing agents and density modifiers
are suitable for use with the present invention.
[0063] In this regard, one particular advantage arising from the
preferred embodiments is the ability to treat the product to be
coated by providing additives in the functional layer. To explain,
since the slurry is dewatered through the product to be coated, it
is possible to provide additives to the base layer by incorporation
in the slurry. For instance, a waterproofing agent such as silane
may be included in the formulation in excess of the functional
layer requirements. During dewatering, the silane will be drawn
into and through the base layer being coated thereby treating the
base layer. This simultaneous treatment of the base layer as well
as providing a functional attribute via the deposited layer is a
valuable additional benefit arising from the aforedescribed
method.
EXAMPLES
[0064] The present invention will now be described by way of
example only with reference to the following embodiments.
[0065] In each of the following examples, the product was produced
as follows.
[0066] Step 1 Slurry Preparation
[0067] A slurry of the formulation is prepared by mixing the
hydraulic binder, fly ash and other optional components with water.
The solids content in the slurry is preferably between about 50 and
90%, more preferably about 55 to 80% and most preferably about 60
to 70%.
[0068] Step 2 Slurry Application/Dewatering
[0069] The slurry is applied to the base layer by any convenient
means such as brushes rollers, knives or sprays etc. The slurry is
designed to self level and form a uniform coating on the product.
The building product to be coated exhibits s certain degree of
porosity causing the slurry to dewater and form a uniform deposited
cementitious layer. Time for dewatering can vary quite dramatically
but normally occurs between about 10 and 90 seconds, depending on
the porosity of the material to be coated, its water content and
thickness and viscosity of the slurry formulation. A vacuum may be
used to reduce the slurry dewatering time if required. This is
particularly useful when tailoring the coating process to the speed
of a building product forming process, eg between about 40 to 45
seconds on a Hatschek production line.
[0070] Step 3 Curing
[0071] After forming, the green laminate article comprising the
building product plus coating is preferably precured for a short
time, eg up to about 48 hours, then cured by air/moist curing at
room temperature, steam curing between about 40 and 90.degree. C.
or autoclaving in a steam pressure vessel between about 120 and
200.degree. C.
[0072] For either of these three curing techniques, a curing time
range between about 6 and 72 hours, preferably up to about 48
hours, is suitable. Of course, as will be clear to persons skilled
in the art, the length of time chosen for curing is dependent on
the formulation, the manufacturing process and form of the
article.
[0073] The following examples relate to specific formulation
compositions.
Example 1
Sandable Dewatered Slurry Composition
[0074] Function: sandable, durable finishing layer for facade
applications.
[0075] The low viscosity slurry (drainage time in 50 ml volume
funnel=3.4 seconds) was applied on the base layer (Hardiform.TM. 12
mm thick cellulose fibre reinforced cement-based green sheet
manufactured by James Hardie Industries). The slurry dewatered in
90 seconds (un-aided by vacuum) forming a 1.25 mm thick coating.
The coated sheet was autoclave-cured for 8 hrs at 180.degree. C.
temperature and 0.80 MPa pressure. It was then sanded flat to 0.60
mm thick using industrial sanders equipped with 100 grit sand paper
belts.
2 % by total Slurry weight of Composition solids (S) Weight in gm
Dewatered Cementitious Composition Portland Cement 30 12000 Silica
Flour (400 G 10 4000 grade) Fly ash (larger size 40 16000 fraction)
Fly ash (smaller size 20 8000 fraction) Total 100 40000 Water (W)
14000 Water/ Solids (W/S 0.35 ratio) Solids Content 0.74 (W/W + S)
Organic Additives Welan Gum 0.0075 3.0 (Kelcocrete) naphthalene
0.25 100.0 formaldehyde Plasticising Agent (Neosyn) Acrylic
Emulsion 1.0 400.0 Rhoplex MC1934
Example 2
Rubberised Dewatered Slurry Composition
[0076] Function: In skid-resistant flooring, hard wearing static
dissipative flooring and acoustic insulating ceiling panels.
[0077] The low viscosity slurry (drainage time in 50 ml volume
funnel=4.2 seconds) was applied on the base layer (Hardiform.TM. 12
mm thick cellulose fibre reinforced cement-based green sheet
manufactured by James Hardie Industries). The slurry dewatered in
60 seconds (un-aided by vacuum) forming a 1.25 mm thick coating.
The coated sheet was autoclave-cured for 8 hrs at 180.degree. C.
temperature and 0.80 MPa pressure. It was then sanded flat to 0.60
mm thick using industrial sanders equipped with 100 grit sand paper
belts.
3 % by total Slurry weight of Composition solids (S) Weight in gm
Dewatered Cementitious Composition Portland Cement 30 12000
Recycled Rubber crumbs 10 4000 (minus 30 mesh) Fly ash (larger size
40 16000 fraction) Fly ash (smaller size 20 8000 fraction) Total
100 40000 Water 13000 Water/ Solids (W/S 0.325 ratio) Solids
Content 0.755 (W/W + S) Organic Additives Welan Gum 0.0075 3.0
(Kelcocrete) naphthalene 0.25 100.0 formaldehyde Plasticising Agent
(Neosyn) Acrylic Emulsion 1.0 400.0 Rhoplex MC1934
Example 3
Flexible & Sandable Dewatered Slurry Composition
[0078] Function: Flexible & sandable layer on thin fibre cement
reinforced cement-based lining.
[0079] The low viscosity slurry (drainage time in 50 ml volume
funnel=2.8 seconds) was applied on the base layer (Hardiflex.TM.
4.5 mm thick cellulose fibre reinforced cement-based green sheet
manufactured by James Hardie Industries). The slurry dewatered in
120 seconds (un-aided by vacuum) forming a 1.25 mm thick coating.
The coated sheet was precured for 48 hours then was autoclave-cured
for 8 hrs at 180.degree. C. temperature and 0.80 MPa pressure. It
was then sanded flat to 0.60 mm thick using industrial sanders
equipped with 100 grit sand paper belts.
4 % by total Slurry weight of Composition solids (S) Weight in gm
Dewatered Cementitious Composition Portland Cement 20 8000 Calcium
Carbonate 10 4000 Grade 10 (40 um avg. size) Alumina Tri-hydrate 5
2000 (80 um avg. size) Fly ash (larger size 45 18000 fraction) Fly
ash (smaller size 20 8000 fraction) Total 100 40000 Water 12000
Water/ Solids (W/S 0.30 ratio) Solids Content 0.77 (W/W + S)
Organic Additive Welan Gum 0.0075 3.0 (Kelcocrete) naphthalene 0.25
100.0 formaldehyde Plasticising Agent (Neosyn) Styrene Acrylic
Latex 5 2000 Emulsion (56% solids)
Example 4
Flexible & Sandable Dewatered Slurry Composition (Low
Cement)
[0080] Function: Flexible & sandable layer on thin fibre cement
reinforced cement-based lining.
[0081] The low viscosity slurry (drainage time in 50 ml volume
funnel=4.5 seconds) was applied on the base layer (Hardiflex.TM.
4.5 mm thick cellulose fibre reinforced cement-based green sheet
manufactured by James Hardie Industries). The slurry dewatered in
90 seconds (un-aided by vacuum) forming a 1.25 mm thick coating.
The coated sheet was autoclave-cured for 8 hrs at 180.degree. C.
temperature and 0.80 MPa pressure. It was then sanded flat to 0.60
mm thick using industrial sanders equipped with 100 grit sand paper
belts.
5 % by total Slurry weight of Composition solids (S) Weight in gm
Dewatered Cementitious Composition Portland Cement 10 4000 Calcium
Carbonate 20 8000 Grade 10 (40 um avg. size) Alumina Tri-hydrate 5
2000 (80 um avg. size) Fly ash (larger size 40 18000 fraction) Fly
ash (smaller size 25 10000 fraction) Total 100 40000 Water 16000
Water/ Solids (W/S 0.40 ratio) Solids Content 0.715 (W/W + S)
Organic Additives Welan Gum 0.0075 3.0 (Kelcocrete) naphthalene
0.25 100.0 formaldehyde Plasticising Agent (Neosyn) Vinyl
acetate-ethylene 1.625 650 powdered copolymer (Vinnapas LL5004)
[0082] The aforementioned examples provide a composite comparable
in workability to monolithic or single layer composites. They can
be flexed, cut, drilled or fixed by nails or the like to a frame
without surface cracking or chipping.
[0083] The surface is `finish-ready` and remains smooth, flat,
crack-free and with low permeability even when used in a curved
configuration.
[0084] Each example provided excellent interlaminer bond between
the base sheet and coating exhibiting good composite action,
compatibility and resistance to delamination.
[0085] The applicants have developed a unique process which allows
them to combine fibre reinforced layers with functional dewatered
slurry layers optional reinforced with a wide range of synthetic or
natural fibres, eg polypropylene, glass, PVA, cellulose fibres etc.
The outcome of the aforementioned method is to produce a fibre
reinforced composite with strength, water resistance,
incombustibility of fibre cement with a low density, surface finish
and insulation properties of, for example, gypsum board.
[0086] The applicants have found that using the techniques
described herein, functional layers can be added to the substrate
layer with no delamination or incompatibility between the layers,
ie no differential shrinking, warping or similar properties.
[0087] It will be understood by persons skilled in the art that the
present invention may be embodied in other forms without departing
form the spirit or scope of the inventive idea as described herein.
In particular, it will be appreciated that the formulations,
coatings, additives, methods and composite products of the present
invention are suitable or may be adapted for use in conjunction
with the methods and apparatus as described in the various priority
documents.
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