Note: Descriptions are shown in the official language in which they were submitted.
CA 02451251 2003-11-27
SPRAY-APPLIED CELLULOSE INSULATION AND METHOD
FIELD OF THE INVENTION
[001] The present invention relates generally to building insulation. More
particularly, the
present invention relates to spray-applied fibre based insulation, most
specifically spray-
applied cellulose fibre insulation.
BACKGROUND OF THE INVENTION
[002] Sprayed cellulose building insulation is generally made from recycled
paper or
paperboard stock modified with chemical additives. It can be applied to open
surfaces or
cavities that will be enclosed later. Cellulose insulation is an alternaive to
commonly used
fibreglass insulation in the form of batts or loose fill. Because of the loose
nature of the
insulation material, sprayed cellulose fibre insulation can be applied to a
wide range of areas,
including attics, walls, floors or any other voids or hard-to-reach crevices
where batt
insulation is not easily applied. It forms a uniform covering throughout the
cavity and forms a
superior air seal around electrical boxes, wiring, pipes and framing members:
To reduce
ignition and combustion danger, the cellulose material is generally treated
with fire
retardants, for example boric acid. Antifungal agents are also generally added
to the
cellulose material to prevent the growth of potential pathogens such as mould.
[003] Cellulose building insulation has been lauded for its energy efficiency
and
environmental friendliness. The manufacture of cellulose insulation uses less
energy (up to
59 times less) and releases fewer greenhouse gases into the atmosphere than
that of
mineral fibre insulation, which reguires vast amounts of heat derived from
natural gas
combustion. In addition to its environmental conservation benefits, spray
applied cellulose
has been shown to possess R-values superior to other loose-fill insulation,
and to reduce air
infiltration, which lowers heating energy costs.
(004] Despite documented and well-established benefits, there are a number of
challenges
to the effective application and use of cellulose insulation in the field.
Blown cellulose fibre
material does not have sufficient integrity to be applied into wall
cavities"dry", which means
without added moisture. To prevent the blown-in "dry" material from falling
out of the wall
CA 02451251 2006-06-09
cavity, some type of retaining structure such as netting must be used which
maintains
the insulation in place. If the insulation is to be permanently applied to a
surface or in a
cavity without such a retaining structure, sufficient water or water and
adhesive mixture
must be added to achieve a bonding of the fibres to one another and to the
surface to
which they are applied. Furthermore, to prevent settlement of the sprayed
insulation, the
fibres are bonded to one another as well as to the substrate to which they are
applied.
This increases the moisture content of the insulation upon application.
[005] Typically, cellulose has an inherent moisture content of 5 to 10%, but
further
moisture is generally added during spray application to bond the cellulose
fibres, in
particular for wall applications. It is the use of this added moisture, which
creates
additional challenges. As insulation loses R-value when wet (hence, reducing
thermal
performance), wet-applied cellulose insulation cannot function at an optimal
level until
adequately dry. Thus, wet insulation needs to be dried in-situ before closing
of the wall
cavity, which delays contractors and building completion. Depending on
environmental
factors, this can lead to costly construction delays, particularly in humid
climates, since
the level of humidity can greatly affect drying times. Further, there is a
perception that
cellulose insulation applied with excessive moisture will lead to problems in
terms of rot
and mould growth. Although this is not true for the cellulose fibres which are
generally
treated against the growth of such pathogens, surrounding untreated building
materials
may already include mould and rot spores which may grow in the presence of
sufficient
excess moisture.
[006] The US Forest Products Laboratory has determined through numerous tests
that
the growth of wood rotting fungi is retarded at an average moisture content of
25-30%
and is completely stopped at 20% based on the oven dry weight condition.
(Textbook of
Wood Technology, McGraw Hill, 4~' edition (1970) eds. A.J. Panshin, C. de
Zeeuw)
Thus, there are concerns that if the insulation remains above a moisture
content of 30%
for extended periods of time there is a potential for mould growth in adjacent
untreated
building materials and, thus, potential health problems. Consequently, a need
exists for
a spray applied cellulose insulation of the lowest possible moisture level.
[007] A high moisture content of the applied cellulose insulation not only
creates
challenges with respect to the growth of pathogens and reduced R-value, but
also
increased density. Since increased densities result in increased material
requirements, a
need exists for a spray
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applied cellulose insulation of the lowest possible density in order to keep
material costs
competitive with other insulation products.
(008] Devices for spray applying insulation have been well documented. Devices
are
disclosed in U.S. Patent No. 1,718,507 (UVenzel et al.), U.S. Patent No.
1,978,125 (Bennett),
U.S. Patent No. 3,606,154 (Tufts), U.S. Patent No. 3,861,599 (Waggoner), U.S.
Patent No.
3,957,209 (Thomson) and U.S. Patent No. 4,236,654 (hello).
(009J Spray-on cellulose insulation has been described in U.S. Patent No.
4,360,440 (Nov.
23, 1982), issued to Boyer et al., which discloses a cellulose insulation
containing 50%
water, 33% cellulose fibres and 17% adhesive resin, the adhesive comprising an
adhesive
mixture of 40% sodium silicate (@ 41% solids) and 60% acrylic resin
(@46%solids).
Assuming an inherent moisture content of the cellulose fibres of
10°I°, the resulting cellulose
insulation has a moisture content on an oven dry weight basis of 167%.
(0010] In this context, oven dry refers to the oven dry testing method known
in the art
wherein for achievement of the oven dry condition the drying conditions are
selected to
completely drive out all moisture in the material and wherein the moisture
content of the
material is expressed in percent of the total weight of the material relative
to the weight of the
material in the oven dried condition.
(0011] U.S. Patent No. 5,684,068 (Nov. 4, 1997), issued to Boyer et al.
discloses insulation
compositions including polyvinyl alcohol (PVOH) cooked without an acidic
medium and
cellulose fibres combined with an acidic medium (boric acid) for spra~on
insulation. The
boric acid is admixed with the cellulose fibres in a dry or dissolved
condition and not admixed
with the PVOH during cooking. The treated cellulose fibres disclosed for use
in spray-on
applications in Table 1 have a moisture content of 10 to 15%, on an oven dry
basis. Samples
were prepared by applying 0.23 gallons (0.87 L) of adhesive mixture to 1 Ib.
(0.45kg.) of
ceNulose fibres. Mixtures were produced using either a 5:1 or 4:1 ratio of
water to resin
mixture. The oven dry moisture content of the resulting insulation would be in
excess of
125%.
(0012] U.S. Patent No. 5,853,802 (Dec. 29, 1998), issued to Boyer et al.
(continuation-in-part
of U.S. Patent No. 5;684,068), discloses a method for treating cellulose
fibres with solid boric
acid at a level of 15-30% by weight, or a mixture of 10-25% solid boric acid
with 0-12%
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aqueous boric acid. The disclosed cellulose insulation for application into
walls also has a
moisture content on an oven dry weight basis of in excess of 125%.
[0013] U.S. Patent No. 6,251,476 {Jun 26, 2001 ), also issued to foyer et al.,
discloses a
method for applying cellulose insulation in walls, wherein the PVOH adhesive
is "cooked"
with or without the presence of an acidic medium, prior to addition to the
cellulose fibres. A
PVOH adhesive mixture is added to the fibres at a level of about 0.05 to about
0.3 gallons
(0.19 - 1.13 L) of adhesive per pound (0.45 kg) of fibres. Further, the ratio
by volume of
water to adhesive resin is between 3:1 to 15:1, resulting in an insulation
density of 1.5 to 6
Ib./ft3. (24.0 - 96.2 kg/m3). On the basis that the oven dry moisture content
of the cellulose is
10% (inherent moisture), the adhesive resin used in the adhesive mixture
contains 30%
solids (i.e. 70% water) and the density of the adhesive mixture is 8.35 Iblft3
the minimum
oven dry moisture content for this method (3:1 adhesive added at a rate of
0.05 gal per
pound of fibre) would be 52%. The maximum oven dry moisture content (15:1
adhesive
added at a rate of 0.3 gal per pound of fibre) for this method would be 270%.
[0014] As is apparent, the prior art discussed above all results in applied
products with a
density in excess of 24.0 kg/m3 (1.5 Ib/ft3) and a moisture content on an oven
dry weight
basis which greatly exceeds the minimum moisture levels required for
preventing fungal
growth. Furthermore, tests with commercially available cellulose systems show
that simply
reducing the amount of added moisture andlor aqueous adhesive to achieve a
total moisture
level in the finished insulation below 30% is not an option, since this
results in an
unacceptable final product. Under the reduced moisture conditions, prior art
cellulose
insulations exhibit insufficient integrity to prevent unacceptable settling
over time and
insufficient wet strength to prevent excessive amounts of material falling out
of the wall cavity
during application. Thus, an improved spray-applied cellulose insulation
system is desired
which permits the achievement of the desired moisture content after
application for limiting
fungal growth, can be economically applied at a lower density to a surface or
cavity and has
sufficient integrity to prevent undesirable settling and has sufficient wet
strength.
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SUMMARY OF THE INVENTION
[0015] It is an object of the present invention to obviate or mitigate at
least one disadvantage
of previous spray-applied cellulose insulation types.
[0016] The inventors of the present cellulose insulation and application
method have
surprisingly found that a cellulose insulation with acceptable integrity and
wet strength for
application to upstanding surfaces such as walls and having a moisture content
below 30%
on an oven dry weight basis can be achieved. The inventors have further found
that such a
cellulose insulation can be reliably applied at this moisture content to
upstanding surfaces,
such as walls, without the previously expected settling and integrity problems
by using an
adhesive system, which provides a gelling of the adhesive upon application
thereof onto the
cellulose. The inventors have also surprisingly found that with the cellulose
insulation of the
invention an insulation density below 24.0 kglrri (1.51b1ft3) can be achieved.
Although the
potential for gelling of certain adhesives during storage was previously
observed as
disclosed in the prior art (see US 5,684,068), this effect was considered
undesirable and was
prevented in the prior art insulation application methods by the addition of
an acidic medium
to the cellulose fibres. The inventors of the present application have now
discovered that,
contrary to the teachings of the prior art, a gelling of the adhesive can be
used to improve the
integrity and wet strength of the cellulose insulation when the gelling is
triggered upon
application of the adhesive to the cellulose during spray application of the
insulation to an
upstanding surface.
[0017] According to one object of the invention there is provided a spray-on
cellulose
insulation including cellulose fibres and an aqueous adhesive resin for
binding the fibres at
application, wherein the moisture content of the cellulose fibre insulation is
less than 30%,
more preferably between about 15% and 25% and most preferably below 20% as
measured
on an oven dry weight basis.
[0018] According to another object of the present invention there is provided
a spray-on
cellulose insulation including cellulose fibres for spray-on application and
an aqueous
adhesive resin for bonding the fibres at application, the adhesive resin being
capable of
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forming a wet gel prior to drying and the cellulose fibres being treated prior
to spray-on
application with an additive which triggers gelling of the adhesive resin upon
application of
the adhesive to the fibres.
[0019] 1n yet another object of the invention, the cellulose fibres are
further treated with a
cross-linking agent.
[0020] In still another object of the invention there is provided a cellulose
insulation having a
density between 16.0 - 24.0 kglm3 ( 1.0 - 1.5 ib/ft ), preferably 20.0 - 24.0
kglm3 (1.25-1.5 Ib/
ft3).
[0021] It is a further object of the present invention to provide a method for
insulating an
upstanding surface by application of the spray-applied cellulose insulation of
the invention,
the method including the steps of selecting an additive/aqueous adhesive resin
combination
resulting in a gelling of the adhesive upon admixture of the adhesive with the
additive,
treating cellulose fibres with the additive, blowing the treated cellulose
fibres onto the
upstanding surface, and spraying the adhesive resin onto the cellulose fibres
prior to the
fibres impinging on the upstanding surface, to trigger gelling of the adhesive
resin upon
application of the cellulose fibres to the surface and prior to setting of the
adhesive resin.
[0022] In accordance with the invention, the aqueous adhesive resin can be
selected among
any of the known resins capable of generating a wet gel under conditions
compatible with
spray application of cellulose insulation. The preferred aqueous adhesive
resin in
accordance with the invention is polyvinyl alcohol or any mixture thereof with
other adhesive
resins, for example polyvinyl acetate, which do not interfere with the gelling
of the adhesive
upon application thereof to the treated cellulose fibres.
[0023] According to yet a further object of the invention, the additive and
the cross-linker are
either different compounds, or a single compound capable of triggering gelling
of the
adhesive as well as functioning as a cross-linker for the adhesive.
[0024] In a further aspect, the invention provides a cellulose insulation
product including
cellulose fibres for spray application to an upstanding surface, the cellulose
fibres having
been treated with an additive for triggering gelling of an aqueous adhesive
resin upon
admixture therewith, and instructions for use of the cellulose fibres in a
spray-applied
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application in combination with the aqueous adhesive resin to achieve a
cellulose insulation
having a total moisture content of less than 30% on an oven dry weight basis.
(0025] In a preferred embodiment, the cellulose insulation product further
includes are
amount of the aqueous adhesive resin separate from the cellulose fibres to
prevent contact
thereof prior to use of the adhesive according to the instructions.
(0026] In still another aspect, the invention provides an adhesive system for
use in spray-
applied cellulose fibre insulation, comprising an aqueous adhesive resin for
application to the
cellulose fibres during spray-application of the insulation, the adhesive
resin being capable of
generating a wet gel, and an additive for triggering gelling of the adhesive
resin upon
admixture therewith. The adhesive preferably includes polyvinyl alcohol (PVOH)
or a mixture
thereof with polyvinyl acetate (PVA). The ratio is preferably from 1 to 10
parts PVA to 1 part
PVOH, more preferably from 1 to 5 parts PVA to 1 part PVOH and most preferably
3 parts
PVA to 1 part PVOH. The additive for use in combination with the PVOH
containing
adhesive must raise the pH of the adhesive to a value above r.0, preferably
above 8.0, most
preferably borates selected from the group of ammonium pentaborate, ammonium
biborate,
sodium pentaborate.
(0027] Preferred additives for use with PVOH containing adhesives are pH
alkaline borates
such as ammonium pentabarate, ammonium biborate and sodium pentaborate, which
simultaneously function as additives triggering gelling of the adhesive and as
crosslinkers
during setting of the adhesive.
(0028] Other aspects and features of the present invention will become
apparent to those
ordinarily skilled in the art upon review of the following description of
specific embodiments of
the invention in conjunction with the accompanying figures.
DETAILED DESCRIPTION
(0029] Generally, the present invention provides a spray-on cellulose
insulation with
improved integrity and wet strength. Specifically, the invention provides a
cellulose fibre
insulation comprising treated cellulose fibres and an adhesive resin for
binding the fibres at
application, wherein the total moisture content of the cellulose fibre
insulation on an oven dry
weight basis is less than 30%.
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[0030] The overall water added to the cellulose fibres of the present
invention is 52~%
(wlw), optionally 10-20% (wlw). The nominal added moisture is derived from the
water,
mixed with the adhesive resin. At a mixing ratio of 3 parts water to 1 part
adhesive resin the
nominal added water is 4 - 18%. The total moisture content of the appled
insulation on an
oven dry weight basis is less than 30%. In this context, applied insulation
refers to the
cellulose insulation directly after spraying the cellulose and adhesive onto
an upstanding
surface such as a wall surface. This takes into account that cellulose has an
inherent
moisture content of 5-10% on an oven dry weight basis. In the following, the
terms "wall
surface" or "wall cavity" are intended to encompass any upstanding surface or
cavity to be
insulated.
[0031] Advantageously, the reduced added moisture significantly reduces and
potentially
obviates drying time, thus allowing construction crews to complete dry wall
and related
structural tasks with tittle or no delay after application of the insulation.
It is a further
advantage of the present invention to provide a reduced-moisture cellulose
fibre insulation
which nevertheless has sufficient wet strength to remain in a wall cavity
during and after
application. By keeping the total moisture content on an oven dry weight basis
below 30%,
fungal growth in raw wood materials surrounding the cellulose insulation is
retarded and by
keeping the total moisture below 25%, fungal growth is virtually eliminated.
It is still a further
advantage of the present invention to provide a cellulose fibre insulation in
which the thermal
degradation period is reduced via a reduction in the amount of time required
for the insulation
to dry down to ambient conditions. Advantageously, reducing the total added
water doss not
compromise the integrity of the insulation as long as cellulose insulation is
applied with an
adhesive/additive combination which provides a gelling of the adhesive upon
mixture with the
additive. It is this gelling of the adhesive upon application, which is
believed to provide
additional wet strength to the insulation upon application, thereby allowing a
reduction in
added moisture previously believed impossible. Adhesives/additive combinations
applicable
for use in the present application include any known aqueous adhesives which
are capable
of generating a wet gel and their respective gel triggering compounds
(additives).
[0032] Prior to spray application, the cellulose fibres are treated with the
additive by either
admixing the additive in a granular or liquid form with the fibres, or by
pounding or spraying it
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CA 02451251 2003-11-27
into the cellulose fibres in a fibre mill. When the adhesive used is or
contains PVOH, the
additive is an alkaline compound used in a sufficient amount to trigger
gelling of the PVOH
upon admixture therewith. Additives preferred for use in combination with PVOH
are alkaline
additives having a pH above 7.0, most preferably above 8Ø The alkaline
additive is used in
an amount sufficient to trigger gelling of the adhesive upon application of
the adhesive to the
treated cellulose fibres. The cellulose fibres can also be treated for use
with PVOH based
adhesive with a crosslinker. Most preferably, the cellulose fibres are treated
with a
crosslinker which is sufficiently alkaline in solution to triggers gelling of
the adhesive upon
contact with the treated fibres. Examples are ammonium pentaborate, ammonium
biborate or
the alkaline earth metal borates. Crosslinkers which are not or only slightly
alkaline can also
be used when combined with a sufficient amount of an alkaline additive to
render the mixture
alkaline in solution. Mixtures of acidic crossfinkers with alkaline additives
in sufficient amount
to render the mixture alkaline in solution are also possible. The alkaline
compound for use in
admixture with the crosslinker is selected to be storage stable and to be
compatible with the
cellulose fibres and the adhesive to be used. An exemplary acidic mixture of
crosslinker and
alkaline compound is boric acid and sodium hydroxide in which the sodium
hydroxide is
added to the resulting mixture in sufficient quantity to achieve alkalinity.
Other alkaline
compounds which may be used are alkali earth metal oxides, bicarbonates;
carbonates or
organic base.
(0033] The cellulose fibres are preferably admixed with a sufficient amount of
fire retardant
to render the insulation compliant with applicable building regulations,
especially regulations
regarding flammability and smoldering resistance. A fire retardant typically
used in the prior
art is boric acid. The cellulose fibres are treated prior to being added to a
hopper used in
applying the treated cellulose to the surface being insulated.
(0034] Gelling testing was performed with exemplary combinations of adhesive
(PVOH
containing) and alkaline additive and the results are shown in the following
Table.
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CA 02451251 2003-11-27
TABLE 1
ExperimentAdhesive - Cellulose Additive Resulf-
Control ~4 parts 1 part No gelling
4% polyvinyl alcoholBoric Acid
1 4 parts 1 part Gelling
4% polyvinyl alcoholBoric Acid + Sodium
hydroxide to raise
pH to
>7.0
2 4 parts 1 part Gelling
4% polyvinyl alcoholBoric Acid + Potassium
hydroxide to raise
pH to
>7.0
3 4 parts 1 part Gelling
4% polyvinyl alcohol4% ammonium
pentaborate (pH
7.8)
4 4 parts 1 part Gelling
4% polyvinyl alcohol4% ammonium biborate
(pH 8.9)
4 parts 1 part Gelling
4% polyvinyl alcohol4% sodium pentaborate
(pH 9.0)
6 4 parts 1 part Gelling
4% polyvinyl alcohol4% sodium bicarbonate
to raise pH to >7.0
7 4 parts 1 part Gelling
4% polyvinyl alcohol4% boric acid +
small
amount of 99% 2-
aminoethanol
8 4 parts 1 part Gelling
4% polyvinyl alcohol4% boric acid +
small
amount of 4N ammonium
hydroxide
(0035] According to the present invention, an adhesive is added to the
cellulose fibres upon
spray-application. In one embodiment, an aqueous adhesive resin comprising 3
parts acetate
and 1 part PVOH is used, although any suitable aqueous adhesive capable of
gelling may be
used. Typically, the adhesive concentration is 1-15% (wlw), preferably 5-10%,
with a anal
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dry adhesive content of 0.25-3% (wlw), optionally 1-2% (w/w). The adhesive is
added to the
cellulose fibres at the moment of spray application to the surface to be
insulated. No pre-
treatment of the cellulose fibres with adhesive or "cooking" is required.
[0036] In a preferred embodiment of the invention, an alkaline crosslinker is
usedwhich
functions as the alkaline additive, namely sodium pentaborate. It is added to
the cellulose
fibres in an amount of 5-15% (wlw), optionally 8-10% (wlw).
[0037] The adhesive on application exhibits a "gelling" effect, instantly
binding the cellulose
fibres to the surface providing a stronger wet bond than if gelling is not
forced. This effect is
not experienced with other commercially available adhesive and cross-linking
mixtures, such
as acrylic-latex. Since the gel-triggering additive is applied to the
cellulose, the gelling effect
does not hinder the application of the insulation because it only occurs after
the cellulose has
been sprayed through a spray nozzle and adhesive applied thereto. Thus, there
exists little
concern for clogging within the spray nozzle and hose.
[0038] To achieve a total moisture content on an oven dry weight basis below
the desired
30% in a cellulose insulation having an initial moisture content between 5- 10
%, the amount
of aqueous adhesive added to the cellulose fibres should be bdween 0.26 and
0.20 L
adhesive/kg of cellulose fibres respectively (0.3 to 0.2 gallons adhesivellb
of cellulose fibres).
Ideally, the final concentration of stock adhesive mixture prior to insulation
application is
about 7% solids. At this concentration the amount of dry adhesive solids added
to the
i:lnished product is between 1.5 to 2.0 %. The adhesive mixture is made by
mixing 3 parts
water to 1 part adhesive resin. At this ratio the nominal amount of water
added to the
insulation is 0.20 to 0.15 L (0.05 to 0.04 gal) and the nominal amount of
adhesive resin
added to the insulation is 0.06 to 0.05 L (0.25 to 0.19 gal).The amount of
added water as
tested (see Example 1 ) was about 10%, resulting in a total moisture content
on an oven dry
weight basis of 18%.
[0039] Because of the reduced added water and the resulting lowering of the
insulation
density, the amount of material required to insulate an area is significantly
lower than with
competing spray-on cellulose insulation systems. Typically, the density
ofcellulose fibre
insulation provided by the present invention is less than 24.0
kglm3(1.51b./ft3) compared to
36.1 kg/m3 (2.25 Ib./ft ) in current commercially available technology.
Advantageously, when
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CA 02451251 2006-O1-26
the cost per weight is factored into the equation, the material cost of using
the insulation of
the present invention is significantly lower than the cost of competing
systems. Even further
reductions in cost can be achieved when the insulation is applied by an
individual with
sufficient skill.
[0040] The present invention further provides a method for insulating a
surface comprising
the steps of treating cellulose fibres with a crosslinker and applying the
cellulose fibres to a
surface by spray mixing the treated cellulose fibres with an aqueous adhesive
resin mixture
to form a cellulose fibre insulation, wherein the cellulose fibre insulation
upon application has
a total moisture content on a oven dry weight basis of less than 30%. The
cellulose fibre
insulation is prepared as described above. The cellulose fibre insulation can
be applied to
any surface, not limited to walls, ceilings, floors and crevices.
[0041] The method comprises blowing treated cellulose fibres under pressure
through a first
hose and spray nozzle and simultaneously applying through a second hose and
under
pressure an aqueous adhesive resin mixture as the treated cellulose fibres
exit the spray
nozzle, which adhesive resin will react with the additive in the cellulose.
The aqueous
adhesive resin mixture will gel upon contact with the treated cellulose, due
to the gelling
triggering additive included in the cellulose.
[0042] The additive is selected to trigger a gelling of the adhesive upon
application of the
adhesive to the fibres.
[0043] For on-site insulation applications, commercially available cellulose
spray application
equipment is preferably used (e.g. KrendIT"", Intec Spray Equipment
Manufacturers). The
cellulose fibres are prepared by an insulation machine and blown under
pressure through an
insulation delivery hose to an application nozzle. Adhesive mixture is pumped
through an
adhesive delivery hose to spray tips adjacent the insulation application
nozzle. The spray
nozzle includes multiple spray tips. Treated cellulose and adhesive are
simultaneously
ejected from the application and spray nozzles respectively to admix prior to
impacting on the
application surface. Bales of cellulose fibre insulation, treated with the
additive, are loaded
into a hopper of the insulation machine. The feed rate and air pressure of the
machine are
adjusted to deliver the insulation at the application nozzle at a
predetermined rate and in an
even and consistent fashion. An adhesive delivery pump is connected to or
placed in a
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CA 02451251 2003-11-27
vessel of premixed aqueous adhesive resin for delivery of the adhesive under
pressure to the
spray nozzle. The pump pressure is adjusted to spray the liquid adhesive onto
the treated
cellulose fibres at a predetermined rate as it exits the nozzle. An operator
remotely and
simultaneously turns on the insulation machine and delivery pump and applies
the insulation
onto a surface in a progressive sweeping and over-lapping fashion until the
desired thickness
or filling is achieved. Excess insulation can be removed from the surface with
a
commercially available insulation scrubber well known to the person skilled in
the art, and
recycled back into the virgin fibre stream through the use of commercially
available insulation
vacuuming and recycling equipment.
[0044) The present invention will be further understood from descriptions of
specific
examples which follow.
EXAMPLE 1
Cellulose fibre insulation in accordance with the present invention was
prepared and
analyzed as follows:
Cellulose in Bales (Thermo-Celi Industries, Ottawa, Canada) 11.35 kg (25 Ib)
per bale
Additive Agent Sodium Pentaborate
Additive Agent Concentration (by weight of insulation): 9.5%
Initial Moisture Content (dry basis): 6.8%
Adhesive: 1:3 PVOH/Acetate Resin
Adhesive Concentration (by weight): 7.5%
The insulation was spray-applied into simulated wall cavities measuring 240 cm
x 37 cm by
14 cm deep, using an insulation machine commercially available from Krendl
Equipment
Company.
The insulation was tested at the National Research Council {NRC) laboratories
in Ottawa,
Ontario, Canada.
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CA 02451251 2003-11-27
NRC Test Results (Report # B-1156.1 ) @ 23 +/- 1 °C and 50 +I- 1 %
relative humidity
Added Moisture: 9.81
Design Density: 22.9 kglm3 (1.4 Iblft3)
Calculated Final Adhesive Content (oven dry basis): 0.85%
Calculated Total Moisture (oven dry basis): 17.1
(0045] The above-described embodiments of the present invention are intended
to be
examples only. Alterations, modifications and variations may be effected to
the particular
embodiments by those of skill in the art without departing from the scope of
the invention,
which is defined solely by the claims appended hereto.
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