CA1336335C - Non-inflammable insulating composite material - Google Patents

Abstract

Disclosed is a non-inflammable insulating, composite material capable of being shooted onto a surface to be coated, such as the wall of a building to be insulated. This material comprises a fibrous-like, synthetic forsterite obtained by calcination of chrysolite asbestos fibers at a temperature from 650° to 1450°C; an inorganic, ligthweight filler selected amongst vermiculite, perlite and their mixtures; and a non-inflammable, hydraulic or silicate binder contained in such an amount as to make the material sufficiently adhesive to be shooted as a coating, either as such or after wetting, onto the surface to be insulated. The weight ratio of the synthetic forsterite to the inorganic filler is ranging from 20:80 to 80:20 to adjust the volumic weight of the final product from about 0.20 to about 0.50 gram per cm3. Also disclosed are methods of manufacturing such a non inflammable, insulating, composite material in a wet, ready-to-be-shooted form.

Description

~ 1 336335 RA~K~TRnUND OF THE INVENTION

a) Field of the invention The present invention relates to a non-inflammable, insulating composite material adapted to be shooted as a coating, either as such or after wetting, onto a surface to be insulated, such as the wall of a building.
The invention also relates to methods of preparing such a non-inflammable, insulating composite material in a wet, ready-to-be-shooted form, and to the coated surface obtained after shooting of the so prepared material.

b) Brief description of the prior art ~ . .
~AnA~;An patent application nu~ber 577,693 filed on S~L~I~eL 16, 1988 in the name of the same Applicant ~ ln~ a~d claims a fibrous-like synthetic forsterite product which is particularly useful as an insulating material. This product which is presently offered for sale under the trademark, FRITMAG and will be called under as such hereinafter, is obtained by subjecting chrysotile asbestos fibers of any c~.æIcial grade, having an MgO : SiO2 ratio lower than 1:1, to calcination at a temperature of from 650 to 1450C.
FRITMAG has a raw loose density of from 3 to 40 pounds per cubic foot, a thermal conductivity K factor of from 0.25 to 0.40 BTU.
in/hr.F.ft2 and a fusion point of about 1600 to 1700C. It po~.~e~e.~
a ~ lLit fibrous structure ressembling that of the ~~ o~ile asbestos fibers from which it derives, although this fibrous structure has shown to disappear upon rough manipulation, when subjected to p.es~ula, or when mixed with other material. Then, the fibrous structure is lost but the product has and always retains a high insulating value which is quite superior to granular fol~e~-lte and similar to KAOWOQL (trademark) or rockwool.

a~

In the above _entioned patent application, it is mentioned that FRITMAG may be used as a substitute for asbestos, whenever a fibrous material to be used in bulk and having high lnsulating qualities is nee~e~. Indeed, FRITMAG is fibrous and has a loose density range substantially identical to asbestos. It also has high insulating plv~eL~ies and is devoided o~ all the lm~e~trable health problems allegedly attributed to asbestos.
In the above mentioned patent application, it is also suggested to mix FRITMAG with an inert filler and a binder in order to form an lnsulating ~u~.~o~ltion adapted to be shooted onto any surface to be insulated or to be mml 1 ~e~ in the ~orm of slabs for roof in~ll~tion. However, no .qpecific example of such a cnmr~cition is given, except for a short reference made in the specification to a possible mixlng with other m-aterials~ such as Portland cement.
Similarly, no method of m~ml~cturing slabs from such a c~..~o~ltion is disclosed, although it is obvious that some of the methods presently used on an lndustrial scale to m~n~cture slabs may not be applicable if FRITMAG is part of the combinatlon, because of the change of structure that has been noticed in this product when it is subjected to pressure or mixed with other material.

SUMMARY OF THE lNV~NlloN

The present invention derives from further studies that have been conducted on FRITMAG since it was first synthetized.
The present invention provides a new, non inflammable, insulating composite material comprising:
- a fibrous-like, synthetic forsterite as defined hereinabove, namely F~ITMAG;

-= ~

- an inorganic, lightweight filler selected amongst vermiculite, perlite and their mixtures; and - a non inflammable binder present ln such an amount as to make the material sufficiently adhesive to be shooted as a coating, either as such or after wetting, on a surface to be insulated, - wherein the weight ratio of FRITMAG to the inorganic filler is ranging from 20:80 to 80:20.
Insulating, composite materials and/or composition specially adapted to be shooted or spreaded either in dry form or in wet form onto a surface in order to in~ll~te the same are well known in the art and commonly used for the insulation of buildings. By way of reference, an eæample of such a known composition is disclosed in U.S.
patent No. 4,710,309 granted to American Sprayed-On Fibers Inc.
The composite material according to this present invention distinguishes over the prior art in that it is eæclusively made of non organic elements. Accordingly, it is really non inflammable and it does not generate smoke in case of fire. Moreover, the composite material according to the invention is adapted to be shooted in a wet form, thereby avoiding the generation of dust during shooting.
The composition mainly comprises vermiculite and/or perlite in admiæture with FRITMAG, in a weight ratio of F~ITMA~ to vermiculite and/or perlite ranging from 20:80 to 80:20. When the ratio FRITMAG to vermiculite is equal to 80:20, the resulting material after shooting has a volumic weight of about 0.50 g/cm3. When the ratio FRITMAG to vermiculite is equal to 20:80, the composite material after shooting has a volumic weight of about 0.20 g/cm3. Accordingly, the volumic weight of final product is ranging from about 0.20 to about 0.50 g/cm3 which is very low, thereby making the composite material according to the invention very efficient as a light weight fibrous insulation and fibrous material.

~ .

~ 1 336335 In accordance with a first embodiment of the invention particularly useful when the surface on which the material is shooted must resist to high temperature, the non-inflammable binder is preferably the silicate-based binder. As such a silicate-based binder, u æ can be made of sodium or pot~ ]m silicate.
In accordance with another embodiment of the invention especially adapted for fire-proofing a building, the non inflammable binder is a hydraulic binder such as Portland cement or plaster.
In both ca æ s, inorganic, reinforcing fibers may be added to the material in such an amount as to improve the cohesion strength thereof. Advantageously, use is made from 1 to 5% by weight of inorganic, reinforcing fibers based on the total weight of the material. Preferably, these fibers are selected amongst glass fibers, ceramic fibers and rock wool.
The present invention also proposes a method of preparing a non-inflammable, insulating composite material in a wet, ready-to-be-shooted ~orm, comprising the steps o~:
- intro~l~c;ng into a concrete mi~er an inorganic, light weight filler selected amongst vermiculite, perlite and their moxtures;
- introducing into said mixer a non-inflammable hydraulic binder such as Portland cement, and FRITMAG; the amount of FRITMAG
introduced to the mixture being so selected that the weight ratio of F~ITMAG to the inorganic filler is ranging from 20:80 to 80:20; the amount of binder introduced into the migture being so selected as to make the resulting material sufficiently adhesive after wetting to be shooted onto a surface to be coated;

-~- 1 336335 - introducing water into the mi~er; and - operating the mixer for 10 to 15 minutes;
- whereby the resulting composite material is ready-to-be-shooted as such onto the surface to be coated.
If desired, from 1 to 5% by weight of inorganic fibers, based on the total weight of solids already introduced into the mi~er, may be progressively added into this mixer while it is operating.
The invention further provides another method of preparing a non-inflammable insulating, composite material in a wet, ready-to-be-shooted form, comprising the steps of:
- introducing into a concrete mixer an inorganic lightweight filler selected amongst the vermiculite, perlite and their mixture;
- intro~ ing into said mixer a non inflammable, silicate binder diluted with water, the amount of binder introduced into the mi~er being so selected as to make the resulting material sufficiently adhesive after wetting to be shooted onto a surface to be coated;
- introducing FRITMAG into the operating mixer, the amount of FRITMAG introduced into the mixture being so selected at the weight ratio of the synthethized forsterite to said inorganic filler is r~n~ing from 20:80 to 80:20 and - operating the mixer for 10 to 15 minutes, where~y the composite material is ready to-be-shooted as such onto the surface to be insulatd.
Once again, inorganic, reinforcing fibers may be added into the mi~ture, such an addition being prefera~ly carried out progressively to avoid the formation of aggregates after introduction of FRITMAG into the mi~er.
The non inflammable, insulating composite material according to the invention has the following advantages:

.

1) as any composite material capable being shooted or spreaded onto the surface to be insulated, its installation is very easy to carry out, as compared to conventional insulating material such as fi~erglass or mineral wool;
2) when use is made of a silicate binder, drying of the material can be carried out at a temperature ranging from ambient to 750C;
3) when use is made of a silicate binder, the resulting material has a melting temperature of about 1450C, and 4) the thermoconductivity K factor of the material is of about 0.70 BTU.in/hr. F.fT~;

5) after heating at 750C, the surface of the material becomes very hard and resistant to erosion and thermal shock;

6) it is not subject to degradation in the case of contact with water; and 7) when use is made of a silicate binder, the material can be used either as a fire proofing material for building, or as an industrial, insulating 8) When use is made of a hydraulic binder, the resulting material must necessarily be dried at ambient temperature and cannot be used over 1000C for a long period of time. The composition cont~ining a hydraulic binder however is less e~pensive than the other one, although it is as insulating as this other one.
Non restrictive examples will now be given to better understand the invention.
EXA~PLE 1 Table 1 hereinafter gives the composition of four different composite materials according to the invention, con~ining a silicate binder. Each composite material was prepared according to the method disclosed hereinabove, and was shooted onto 30 cm x 30 cm stainless steel plates, using a spraying m~hine of trademark ARFA.

_7_ 1 336335 The plates coated with the composite materials were dried at ambient for 24 hours and subsequently placed into an autoclave 24 hours at 105C.

TABLE I

OO~ONENTS OO~PCSITIQN

#1 #Z #3 #4 FRITMAG (kg) 15.6 11.7 7.8 3.9 Vermiculite No. 3 (kg) 3.g 7.811.7 15.6 Glass fibers* (kg) 0.6 0.6 0.6 0.6 Sodium silicate N (liters) 4.2 4.2 4.2 4.2 Water (liters) 37.8 37.83?.8 37.8 Weight ratio FRIT~G 80/20 60/4040/6020/80 vermiculite volumic weight (gr/cm3) 0.51 0.45 0.43 0.28 BTU.in 0.73 0.710.70 0.55 hr.F. ft 2 * FTR~RrTTA~s R Canada 6 mmm 303 wet.

As can be noted, the volumic weights ranged from 0.51 to 0.28 g/cm3 while the thermal conductivity factor K ranged from 0.73 to 0.55 for a weight ratio of F~ITMAG to vermiculite ranging from 80:20 to 20:80.
Example 2 Composition No. 2 of e2ample 1 was shooted onto 30 cm ~ 30 cm stainless steel plates. The thickne-~ses of the layer of material that was shooted onto the plates, were equal to 0.50; 0.75; 1.00; 2.00 and 3.00 inches, respectively. The plates were dried at ambient temperature for 24 hours and placed into an autoclave for 24 hours at 105C.
These plates were tested by the Applicant as follows:
- a 8" x 8" opening was made in the horizontal top wall of an oven designed to reach temperature as high as 1000C. A stainless steel mesh was placed over the opening, to act as a support for the coated plates to be tested. A heating element wa~s placed into the oven, just under the coated plates. A thermocouple was placed onto the lower surface of the test plates to measure their temperature. Three other thermocouples were placed onto the upper surface of the tested plates to measure the temperature of the cold side of these plates at different location over a period of 150 minutes. The results obtained with this testing method which permits to compare the thermal in~ll~tion resistance of the tested plates as a function of time are given in table II hereinafter.
By way of comparison, tests were carried out at the same condition with an available commercial, insulating material of trademark ~NQ~OTE.

1 3~6335 TABLE II

VARIATION OF TEMPERATURE (C) ON TIIE COLD SID~ OF THE PLATL AS A
FUNCTION OF TlME (the other side of the plate being heated at 1000C) Composition No. 2 MONo~OTE R

Thickness (inch) Time (inch) .50 .751.00 2.00 3.00 0.901.46 ~25 145 98 58 52 87 51 253 210 1~9 132 90 163 196 gO 248 212 171 136 95 169 178 As can be noted, the insulating ca~acity of the insulating, composite material according to the invention is substantially identical to the one sold under the trademark MONQKO~E. However, contrary to the ~NUK~l~ material which deshydrated after only one cycle of heating the insulating composite material according to the invention shown no visible sign of desaggregation and no variation of te~perature on its cold side after 15 cycles of heating.

Example 3 Composition No. 2 of example 1 was shooted as disclosed hereinabove onto the internal wall of the combustion chamber of a standard, maple syrup evaporator. The thickness of the coating that was shooted was 1.5". The evaporator was 18" wide x 9' long. A gas burner was used and the combustion chamber was heated at a temperature of 750C.
After application of the composite material according to the invention, the burner was switched on and the temperature was measured directly against the combustion chamber on the external lateral surface of the evaporator. The results that were so obtained are shown in Table III hereinafter.
TABLE III

EVOLUTIQN OF T~E TEMPERATUKE (C) OF THE EXTERNAL, COLD SURFAOE OF A
GAS-HEATED EVAPORATOR AS A FUNCTION OF TIME
(INTE~NAL TEMPERATU~E OF EVAPO~ATOR: 750C) Composition No. 2 Ceramic fibers Time initial first fifth first (minute) drying operation operation operation cycle cycle cycle C C C ~

Composition No. 2 Ceramic fibers Time initial first fifth first (minute)drying operation operation operation cycle cycle cycle C C C C

135 87 122 llg 112 240 .88 123 122 111 After shooting, the temperature stay at about 80 to 90C for 220 minutes, during the initial drying. Thereafter, subsequent cycles of operation were carried out, each for a period of 8 hours. The reported tests show that the egternal temperature remained the same fram the first to the fifth cycles of operation. After five operations of 8 hours, the shooted material showed no sign of desaggregation.

By way of comparison, the same test was carried out on the same kind of evaporator provided with a 1'~ layer of ceramic fibers insulation, and with a 1" thick mineral wool insulation. After one cycle of operation, this insulating coating showed sign of desaggregation at the flame-le~he~ surfaces of the evaporator.

Example 4 The composition No. 5 given in Table IV hereinafter was shooted onto 30 cm x 30 cm stainless steel plates, using the method disclosed hereinabove. The composition that contain a hydraulic binder, namely Portland cement of type 10, was shooted to form 0.80, 1.22; 1.73 inches thick coatings, respectively. The plates were kept at ambient temperature for a period of 3 weeks and dried it in an autoclave for 24 hours at 105C. The volumic weight of the final product was 0.40 g/cm3. ~eating tests were carried out and the results of these tests are reported in Table V, hereinafter.

TABLE IV

Composition No. 5 FRITMAG 5 kg Vermiculite ~o. 3 15 kg Glass fiber 1 kg Portland cement (type 10)10 kg Water 85 liters TABLE V

EVOLUTIQN OF THE TEMPERATURE (C) OF THh' OOLD SIDE OF THE TESTED
PLATE$ AS A FUNCTION OF TIME
(H0T SIDE AT 1,000C) Composition No. 5 \ Thickness \ inch 0.8 1.22 1.73 Tim~ c oo C ~ C
~mn) \ 91 92 39 . 161 109 75 105 202 168 14g 135 195 167 14g As will be noted, the insulating capacity of composition No.
5 according to the invention is substantially identical to the one of eæample II. However, when ~h~rm~l stress tests were carried out, signs of desaggregation appeared on the insulating material of composltion No. 5 after 5 to 6 cycles.

Claims (20)

1. A non-inflammable insulating, composite material comprising:
- a fibrous-like, synthetic forsterite obtained by calcination of chrysotile asbestos fibers at a temperature of from 650°C to 1450°C, said synthetic forsterite having an MgO: SiO2 ratio lower than 1.1, a raw loose density of from 3 to 40 pcf, a thermal conductivity "k" factor of from 0.25 to 0.40 BTU. in/hr.°F.ft2 and a fusion point of from 1600° to 1700°C;
- an inorganic, lightweight filler selected amongst vermiculite, perlite and their mixtures; and - a non-inflammable binder present in such an amount as to make the material of sufficiently adhesive, after wetting to be shooted as a coating onto a surface to be insulated, - wherein the weight ratio of said synthetic forsterite to said inorganic filler is ranging from 20:80 to 80:20.

2. The composite material of claim 1, wherein said non-inflammable binder is a hydraulic binder.

3. The composite material of claim 2, wherein the hydraulic binder is Portland cement.

4. The composite material of claim 1, wherein said non-inflammable binder is a silicate binder.

5. The composite material of claim 1, further comprising:
- inorganic, reinforcing fibers in such an amount as to improve the cohesion strength of said material.

6. The composite material of claim 1, comprising from 1 to 5% by weight of inorganic, reinforcing fibers based on the total weight of the material and wherein said inorganic fibers are selected amongst glass fibers, ceramic fibers and rockwool.

7. The composite material of claim 2, comprising from 1 to 5% by weight of inorganic, reinforcing fibers based on the total weight of the material and wherein said inorganic fibers are selected amongst glass fibers, ceramic fiber and rockwool.

8. The composite material of claim 3, comprising from 1 to 5% by weight of inorganic, reinforcing fibers based on the total weight of the material and wherein said inorganic fibers are selected amongst glass fibers, ceramic fiber and rockwool.

9. The composite material of claim 4, comprising from 1 to 5% by weight of inorganic, reinforcing fibers based on the total weight of the material and wherein said inorganic fibers are selected amongst glass fibers, ceramic fibers and rockwool.

10. A surface coated with a layer of non-inflammable, insulating composite material as claimed in claim 1, shooted in a wet form.

11. A surface coated with a layer of non-inflammable, insulating composite material as claimed in claim 2, shooted in a wet form.

12. A surface coated with a layer of non-inflammable, insulating composite material as claimed in claim 3, shooted in a wet form.

13. A surface coated with a layer of non-inflammable, insulating composite material as claimed in claim 4 shooted in a wet form.

14. A surface coated with a layer of non-inflammable, insulating composite material as claimed in claim 6 shooted in a wet form.

15. A method of preparing a non-inflammable, insulating, composite material in a wet, ready-to-be-shooted form, comprising the steps of:
- introducing into a concrete mixer an inorganic, lightweight filler selected amongst vermiculite, perlite and their mixtures;
- introducing into said mixer a non-inflammable hydraulic binder and a fibrous-like, synthetic forsterite obtained by calcination of chrysotile asbestos fibers at a temperature of from 650°C to 1450°C, said synthetic forsterite having an MgO: SiO2 ratio lower than 1.1, a raw loose density of from 3 to 40 pcf, a thermal conductivity "k" factor of from 0.25 to 0.40 BTU. in/hr.°F.Ft2 and a fusion point of from 1600° to 1700°C;
- the amount of synthetic forsterite introduced into said mixer being so selected that the weight ratio of said synthetic forsterite to said inorganic filler is ranging from 20:80 to 80:20;
- the amount of said binder introduced into said mixer being so selected as to make the resulting material sufficiently adhesive after wetting to be shooted onto a surface to be coated;

- introducing water into said mixer; and - operating said mixer for 10 to 15 minutes; whereby the resulting composite material is ready to be shooted as coating onto said surface to be insulated.

16. The method of claim 15, comprising the additional step of:
- progressively adding in said operating mixer from 1 to 5%
by weight of inorganic reinforcing fibers, based on the total weight of solids already introduced into said mixer.

17. The method of claim 16, wherein said hydraulic binder is Portland cement and said inorganic fibers are selected amongst glass fibers, ceramic fibers and rockwool.

18. A method of preparing a non-inflammable insulating, composite material in a wet, ready-to-be-shooted form, comprising the steps of:
- introducing into a concrete mixer an inorganic lightweight filler selected amongst vermiculite, perlite and their mixture;
- introducing into said mixer a non-inflammable silicate binder diluted with water, the amount of said binder introduced into said mixer being so selected as to make the resulting material sufficiently adhesive after wetting to be shooted onto a surface to be coated;
- operating said mixer;
- introducing into said operating mixer up to 70% by weight of a fibrous-like synthetic forsterite obtained by calcination of chrysotile asbestos fibers at a temperature of from 650°C to 1450°C, said synthetic forsterite having an MgO: SiO2 ratio lower than 1.1, a raw loose density of from 3 to 40 pcf, a thermal conductivity "k"
factor of from 0.25 to 0.40 BTU. in/hr.°F.Ft and a fusion point of from 1600° to 1700°C; the amount of synthetic forsterite introduced into said mixer being so selected that the weight ratio of said synthetic forsterite to said inorganic filler is ranging from 20:80 to 80:20;

- operating said mixer for 10 to 15 minutes, whereby the resulting composite material is ready to be shooted as coating onto said surface to be insulated.

19. The method of claim 18, comprising the additional steps of:
- progressively adding in said operating mixer, after introduction of said synthetic forsterite, from 1 to 5% by weight of inorganic, reinforcing fibers, based on the total weight of solids already introduced into said mixer.

20. The method of claim 19, wherein said non-inflammable silicate binder is selected amongst sodium silicate and potassium silicate and said inorganic fibers are selected amongst glass fibers, ceramic fibers and rock wool.