Fluff-type organic insulating pulp and method of fabrication and application

Abstract: An insulating pulp for insulating buildings and other type structures and wherein the pulp is formed of organic fibers having a fiber length of from about 1.0 mm to 3 mm. Such pulp is obtained by a chemi-thermomechanical pulping process and the pulp may be supplied in fluff form or compressed sheet form which is later defibrillized. A fire retardant additive and a corrosive buffing agent is added to the pulp. A major characteristic of such insulating pulp is that it has a density in the range of from about 0.7 to 2.0 lbs/ft³ and has an excellent thermal insulation value of about R3 to R4 per inch. The chemi-thermomechanical wood pulp is produced from debarked trees which are primarily black spruce which have these long and strong fibers. The pulp is applied by injecting it through a compressed air conduit and at the same time an adhesive is injected in the pulp to form a binding agent. Because of the property of the fibers and the fiber distribution in the fluff, the pulp is also an excellent acoustical insulator.

Description: The invention relates to an insulating pulp for insulating buildings and other type structures, said pulp comprising organic fibers having a fire retardant additive, an antibacterial additive and a corrosive buffing agent. The invention further relates to a method of producing an insulating pulp of the initially named kind. It is known to provide insulation as loose fill material and to inject the same into cavities provided in structures, reference is made to U.S. patent 4,829,738 as an example of this. The majority of these free flowing thermal insulating materials are formed from inorganic substances which are treated with various additives having fire retardants or anti-corrosive properties. Some of the inconveniences of such loose fill insulation is that it is awkward to manipulate and transport and produces a lot of dust when disturbed, such as during the application thereof in building structures. A still further major disadvantage of such insulation is that it is difficult to get a substantially even distribution thereof in cavities which are disposed in vertical planes as the insulation has a tendency of propagating towards the bottom of the cavity by gravity. The result is that eventually the wall structures of buildings have a higher density of insulation at the bottom and minimal or none whatsoever in the top portion thereof where the maximum amount of heat is found and escapes through the wall. In an attempt to alleviate this problem, some have suggested placing a net inside the cavity or on the face wall of the cavity, such as disclosed in U.S. patent 4,712,347. This is an expensive, time-consuming solution and due to the property of most insulations, and particularly its density, it is still difficult to obtain a substantially even distribution of insulation within cavities. Thermal insulating material of cellulosic fibers is known from U.S. patent 4,349,413 which is prepared by treating wood chips or other fibrous cellulosic material with saturated steam at elevated temperatures and pressures and then fiberising the treated material. Fire retardant chemical is added to the material prior to fiberisation. The resulting fiberised cellulosic material when dried is flame and fire resistant. Hard or soft wood chips are used for the fibrous cellulosic material. Various bonding, fire-proofing and mold-preventing agents are added to the material during its processing. This thermal insulating material finds application in the walls, floors, or attic of a home or other type of building which must be protected against heat losses. An inorganic composition for use as a fire and flame resistant additive to cellulose fiber thermal insulating material is known from U.S. patent 4,184,969. The composition consists essentially of 10 to 25 parts by weight of alumina trihydrate, 25 to 35 parts by weight of ammonium sulphate, 20 to 35 parts by weight of borax, 10 to 20 parts by weight of boric acid, up to 25 parts by weight of nepheline syenite, and up to 2 parts by weight of soda ash. It is an object of the invention to provide an insulating pulp of the initially named kind which has improved properties, in particular which acts as an efficient thermal insulator, which can be fluffed up to provide an insulating pulp of low density and which is convenient to apply in a space of a building structure or other type of structure to be insulated. The object of the invention is satisfied by an insulating pulp in accordance with the characterising part of claim 1. The object is further satisfied by a method of producing an insulating pulp comprising the steps of claim 14. The insulating organic pulp of the invention is advantageously made by a CTMP pulping process. The pulp can be provided in fluff form or compressed sheet form. If provided in compressed sheet form it can be reconstituted to its fluff form before application as a loose insulation within cavities of building structures. The loose insulation has much less weight per thermal resistance factor R and has excellent acoustical properties. The thermal insulating value is typically in the range of 1.2 to 1.6 per cm (3 to 4 per inch i.e. R3 to R4) The insulating pulp of the invention is highly compressible into sheet- or brick-like form or any other form suitable for injection into a defiberising machine which can be utilised on site to reconstitute the pulp into its fluff form prior to injection into building cavities. The fluff insulation has the further advantage that it produces negligible dust. The insulating pulp of the invention can be compressed in sheet form and defiberised on site for injection into a building structure, wherein a small supply of such sheet form pulp produces a large volume of the insulation in its fluff form. The insulating pulp, in its fluff form, can be packaged loose in bags and applied as loose insulation, or packaged in strip form with support facing sheets similar to fiberglass insulation and packaged in bundles or rolls. A portable insulating pulp applicator machine can be used for ejecting insulating pulp of the invention in fluff form into a space of a building structure or other type of structure to be insulated. BRIEF DESCRIPTION OF DRAWINGS : A preferred embodiment of the present invention will now be described with reference to the accompanying drawings in which: FIGURE 1 is a plan view of the fiber distribution of the fluff pulp as viewed under a microscope; FIGURE 2 is a simplified schematic illustration of a system and process for producing the organic insulating pulp of the present invention; and FIGURE 3 is a schematic illustration of the essential elements of a portable insulating pulp applicator machine. DESCRIPTION OF PREFERRED EMBODIMENTS : Referring now to the drawings, and more particularly to Figures 1 and 2, there is shown a microscopic view of the organic insulating pulp 10 of the present invention and the system and process of manufacturing same. The pulp 10 is an organic wood pulp which is produced by a BCTMP, that is to say, a chemi-thermomechanical pulping process which is only schematically illustrated in Figure 2, as such process is well known in the art for producing fluff which is utilized in sanitary products. Such process utilizes debarked trees and primarily black spruce or balsam fir or pine or a combination of two or three of these trees to provide a pulp in a fluff form. We have found, unexpectedly, that such fluff has excellent thermal insulation factor as well as good acoustical properties. It is pointed out that these trees produce wood fibers having fiber lengths of from about 1.0 mm to 3 mm and their fiber distribution, in fluff form, produces a product which has a density in the range of about 11.16 to 55.80 kg/m 3 (0.7 to 3.5 lbs/ft 3 ) and more particularly a fluff insulating pulp having a density from 11.16 to 31.90 kg/m 3 (0.7 to 2.0 lbs/ft 3 ). The fibers are also hollow core fibers and when used as a thermal insulating material, it was surprisingly found to contain an insulating value R of from about 1.2 to 1.6 per cm (3 to 4 per inch, i.e. R3 to R4). Because of the air contained within these fibers and the fiber distribution in a fluff form, it was also found to possess excellent acoustical properties. In order for the fibers 11 or the fluff to be used as an insulating material, it is necessary to modify the pulping process to add a fire retardant additive, an anti-bacterial additive, as well as a corrosive buffing agent, as illustrated in Figure 2. The fire retardant additive is added in the range of about 10 to 25% by weight of the pulp and the anti-bacterial additive is added in the range of from about 0.1% to 10% by weight depending on the intended use of the insulation. The corrosive buffing agent is also in this range of 0.01 to 10% and also depending on the intended use of the product. As shown in Figure 2, the insulating pulp may be provided at the output of the CTMP pulp process 13 in a fluff pulp form 14 where the fluff is then sent to a bagging or packaging machine to produce bags of fluff insulation. As also shown in Figure 2, the pulp can also be provided in a compressed sheet form to produce a roll 15 of an insulating pulp sheet having the above-described fiber characteristics. The roll can then be cut in individual sheet form 16 to form stacks of sheets or rolls 16' which are easy to transport so that a large quantity of insulating fluff pulp can be transported by a very small vehicle and occupying very little space on site. It is also pointed out that since about half the volume of this pulp can provide comparable insulating factors as with ordinary loose fill insulation or glass fiber insulation, much less material is utilized in building structures making them more lightweight. The lightweight characteristic as well as the compressed sheet form characteristic of the product is also of major importance to insulating contractors. The manufacturing process of Figure 2 can also be modified to feed another insulating material to mix with the fluff to provide a blended insulating material. For example, recycled paper can be added to the fluff in fiber form and in predetermined quantities. This would provide a use for recycled paper. The fluff can also be packaged in bags as loose insulation, or in blanket form, like fiberglass insulation. Such could be cut in panels and pressure-packed, or provided in roll form. It is to be noted that the insulation of the present invention is biodegradable when eventually a building structure with such insulation is demolished and the material is buried in ground. Hereinbelow are Tables illustrating the sheet properties and the fiber properties of the insulating pulp of the present invention. SHEET PROPERTIES Properties Minimum Maximum Basis weight (Gr/M 2 ) 300 900 Moisture (%) 5.0 15.0 Kamas energy (Wh/Kg) 40.0 120 Burst (Kpaxm 2 /Gr) 1.0 3.0 Bulk (Cm 3 /Gr) 2.0 4.0 Breaking Length (Cm 3 /Gr) 2.0 6.0 Tear (Mnxm 2 /Gr) 6.0 15.0 Freeness (CFS) 150 700 FIBER PROPERTIES Properties Minimum Maximum Fiber length (mm) 1.0 3.0 Brightness (ISO) 50.0 80.0 DCM extract (%) 0.05 10.0 Fiber Classification R14 5.0 40.0 by Bauer McNett 14/28 15.0 40.0 Classificator (%) 28/48 30.0 13.0 48/100 10.0 5.0 100/200 10.0 1.0 P200 30.00 1.0 Shives (%) 0.05 10% Knots (%) 2.0 20% Wood Species - Conifer Black spruce 0 100% Balsam fir 0 100% Pine 0 100% An example only of the chemical additives that may be added to the pulp is shown in the following table. CHEMICAL ADDITIVES Chemical Addition Rate Min. Max. Fire retardant (% by weight) Borax 10.0 25.0 Bacteria / (%), Slimecide 0.01 10.0 Corrosive / (%), Buffing agent 0.01 10.0 In summarizing the characteristic of the fluff insulating pulp of the present invention, it is produced by a CTMP pulping process utilizing wood chips having the above-referred to fiber characteristics. The conventional chemi-thermomechanical wood pulp process is modified wherein to mix in the necessary additive to produce a fluff pulp having proper insulation characteristics as required by building codes. The mill's wood supply for the process is mainly black spruce and balsam and these are characterized as having a very slow growth rate and produce extremely strong, long fibers which we have surprisingly found to produce a fluff pulp insulation which has excellent insulating properties which were heretofore unknown. Briefly summarizing the PCTMP modified pulping process, with reference specifically to Figure 2, wood chips 17 are produced from logs of about 2.4 meters of black spruce and balsam, usually 80% spruce and 20% balsam and these chips contain usually a maximum of 0.5% residual bark. These chips are heated to 35°C. using steam and are washed using fresh water which is heated to 60-70°C. The chips are separated from the wash water and are heated to 90°C. in a bin. The chips are compressed into a plug screw feeder 18 to remove air and help in the absorption of the sodium sulphite solution in the impregnator. Usually, 1-6% of Na 2 SO 3 by weight of the chips is utilized. The sodium sulphite is produced as follows: S + (combustion) O 2 = SO 2 SO 2 + H 2 O = H 2 SO 3 H 2 SO 3 + NaOH + NaHSO 3 + H 2 O NaHSO 3 + NaOH = Na 2 SO 3 + H 2 O The PH of the Na 2 SO 3 solution is 9.0 to 10.0. In the reaction bin 19, the sodium sulphite solution reacts with the lignin (sulphonation) at a temperature of 95°C. for about 30 minutes. The chips are pressurized using the plug screw feeder and the pressure is raised to about 35 psi. In the feeder, the chips are pressurized to about 2.4 bars (35 psi) and the refined pulp is separated from steam in the refiner 20 which is also 2.4 bars (35 psi) and pumped into a latency chest where the pulp is agitated at 60°C. to remove the latency in the pulp. The pulp is then screened using two stages of pressure screens schematically illustrated at 21 with the accepted pulp from the screens being passed through two stages of centricleaners as illustrated at 22. The rejected pulp from the screens and the cleaners, which is about 30% of the total feed, is thickened, refined in a reject refiner, screened and cleaned in an independent reject treatment system (not shown). The pulp from the centricleaners is then washed and thickened in a disc filter and inclined screens by water displacement at a temperature of 60°C. The pulp is then stored and when it is pumped out, the pH is adjusted at 7.0 using sulphuric acid. The insulating pulp, in sheet form, is illustrated at 15 and is produced on a fourdrinier machine, well known in the art. Pressing and drying follows to drop the moisture content to about 10%. The rolls 15 of this insulating fiber sheet can then be sent to a winder or layboy which cuts the rolled sheet into different widths and other desirable sheet and roll forms (16 and 16'). The slimecide anti-bacterial additive may be applied at two positions within the process, one position being located at the output of a high density tower and the other in the wire pit where the white water is reserved for the pulp machine, these positions being well known to a person skilled in the art and knowledgeable of CTMP pulping process. The buffing agent should be injected in the system at the high density tower to be sure that the cure time is long enough. The fire retardant additive, herein borax, and other substitute additives can also provide excellent results, is added at a location where the concentration of the product can be controlled with high precision and there are a variety of other positions within this process and, ideally, the application can be done in the third press, the breaker stack-in or the breaker stack-out, the reel drum, or the winder section. This fire retardant liquid can be applied by a spray boom which is positioned over the pulp. Referring now to Figure 3, there is schematically illustrated a portable applicator machine for the insulating pulp of the present invention. If the roll 16' of compressed organic insulating fluff pulp is provided, such roll, or individual sheets 16, can be supported on a mobile platform 30 which is transportable by vehicle directly to the site with the sheet 16 or 16' of compressed pulp fibers being fed to a fibrillizer machine 29 where a fibrillizing means such as the rotating hammers 31 reconstitute the compressed pulp into its loose fluff form as shown at 32. The pulp falls into a feed bin 33 where it is fed into a blowing line 34 by compressed air from a compressor 35. A glue tank 36 feeds a supply of glue into an applicator nozzle 37 where the glue is mixed with the fluff pulp to provide a binding agent so that the fluff pulp adheres together and to surrounding surfaces of a space or cavity to be insulated. As shown in the exploded view, the ejector 37 may have a rectangular wedge shape so as to be used to puncture permeable non-woven tissues which are provided in wall structures whereby to form slits therein to provide openings for the evacuation of air and also to permit insertion of the nozzle within the cavity. Usually, when insulating walls of a building structure, a polyethylene sheet is positioned on the inside open surface between the studs and the sheet is slit to provide for the evacuation of air when insulation is injected under pressure. The use of clear polyethylene also provides a visual means to the person applying the insulation to ascertain that insulation is positioned everywhere in the space covered by the plastic sheet. Although Figure 3 shows a fibrillizer fed by a roll of compressed insulating pulp of the present invention, the machine can also be adapted to fibrillize individual sheets of compressed insulating pulp. The provision of the pulp in sheet form has many advantages, such as making it easily storable for retail by lumber or hardware suppliers, makes it easy to manipulate due to its light weight and to transport, occupies minimum storage area as compared with glass fiber batts, produces very little dust, and most of all, eliminates the problem of having to transport large packages of insulation. A small package of sheets of the compressed pulp of the present invention may be sufficient to insulate an entire home, let alone a single room therein. It is within the ambit of the present invention to cover any obvious modifications of the preferred embodiment describe herein, provided such modifications fall within the scope of the appended claims.

Claims: An insulating pulp (10) for insulating buildings and other type structures, said pulp comprising organic fibers (11) having a fire retardant additive, an antibacterial additive and a corrosive buffing agent, characterized in that said organic fibers have a fiber length lying in the range from 1.0 mm to 3.0 mm.' An insulating pulp as claimed in claim 1, wherein said pulp is a chemi-thermomechanical pulp, said fire retardant additive being in the range of from about 10% to 25% by weight of said pulp, said antibacterial additive being in the range of from about 0.01% to 10.0% by weight of said pulp, and said corrosive buffing agent being in the range of from about 0.01% to 10.0% by weight of said pulp. An insulating pulp as claimed in claim 2, wherein said pulp is compressed to a sheet form. An insulating pulp as claimed in claim 2, wherein said pulp is a fluff-type pulp having a density in the range of from about 11.16 to 55.80 kg/m 3 (0.7 to 3.5 lbs/ft 3 ), in particular 11.16 to 31.90 kg/m 3 (0.7 to 2.0 lbs/ft 3 ). An insulating pulp a claimed in claim 4, wherein said fluff-type pulp has a thermal insulating value of from about 1.2 to 1.6 per centimetre (3 to 4 per inch, i.e. R3 to R4) An insulating pulp as claimed in claim 2, wherein said organic fibers are black spruce, balsam fir or pine fibers or a combination of two or three of these fibers. An insulating pulp as claimed in claim 2, wherein said fire retardant additive is borax or equivalent chemical compound. An insulating pulp as claimed in claim 2, wherein said antibacterial additive is slimecide or equivalent chemical compound. An insulating pulp as claimed in claim 1, wherein said insulating pulp is a thermal and sound insulating pulp. A fluff insulating pulp as claimed in claim 4, wherein said fluff insulating pulp contains glue as a binding agent to adhere said fluff in a space bound by surfaces of said buildings or other type structures. A fluff insulating pulp as claimed in claim 4, wherein said insulating pulp is packaged in a blanket form. A method of producing an insulating pulp (10) for insulating buildings and other type structures, said method comprising the steps of: i) producing a chemi-thermomechanical wood pulp from debarked trees having wood fibers (11) of a length lying in the range from about 1.0 mm to 3 mm; ii) mixing in said pulp a fire retardant additive. iii) mixing an antibacterial additive with said pulp; and iv) mixing a corrosive buffing agent with said pulp. A method as claimed in claim 12, wherein said fire retardant additive is in the range of from about 10% to 25% by weight of said pulp, said antibacterial additive being in the range of from about 0.01% to 10.0% by weight of said pulp, and said corrosive buffing agent being in the range of from about 0.01% to 10.0% by weight of said pulp. A method as claimed in claim 12, wherein said step (i) includes producing said pulp from black spruce, balsam fir or pine trees or a blend of two or three of these. A method as claimed in claim 12, wherein said step (ii) comprises injecting said fire retardant additive in said pulp by means of a spray boom located in a phase of said chemi-thermomechanical wood pulp process where the concentration of said additive can be controlled. A method as claimed in claim 12, wherein said antibacterial additive is injected in said pulp at an output of a high density tower in said chemi-thermomechanical wood pulp process or at a wire pit stage in said process where white water can be reserved. A method as claimed in claim 12, wherein said buffing agent is injected in said chemi-thermomechanical wood pulp process at a high density tower stage in said process to be sure that there is sufficient cure time. A method as claimed in claim 12, wherein there is further provided the step of compressing said pulp to form a compressed insulating pulp sheet capable of being fibrillized to form a pulp fluff. A method as claimed in claim 12, wherein there is further provided the step of forming a fluff from said pulp.

Inventors: BOISVERT ANDRE, FORTIN MICHEL E, LEMAIRE BERNARD, BOISVERT, ANDRE, FORTIN, MICHEL E., LEMAIRE, BERNARD
Applicants: CASCADES INC, CASCADES INC.
Application year: 1991
Main classification: E04B1
IPC codes: E04B1, D21H11, E04F21