Molding and coating compositions

Compositions are provided which employ a fibrous, cellular, absorbent organic material in place of asbestos fiber as a reinforcing and thickening additive; a wide variety of compositions including cements, sealants and paints can be made; a particularly preferred fibrous material is a foamed urea-formaldehyde crushed to a fibrous mass.

BACKGROUND OF THE INVENTION 
a. Field of the Invention 
This invention relates to compositions containing a thickening and 
reinforcing fibrous organic material in an organic binder and a liquid 
vehicle for the binder; more particularly the invention is concerned with 
the use of a fibrous organic material in place of asbestos fibres in a 
wide variety of moldable, brushable and sprayable compositions, for 
example, sealants, roofing cements and coating compositions. 
B. Description of the Prior Art 
Asbestos a complex mineral fibre derived from the mineral crysolite 
composed mainly of magnesium, aluminium silicates is widely used as a 
filler having both reinforcing and thickening properties in a variety of 
moldable, brushable and sprayable compositions. Such moldable compositions 
include plastic cements, roofing cements, sealants, caulking compositions, 
weather proofing compositions, roof coating compositions, insulation 
coating compositions and sheet forming compositions. Brushable and 
sprayable compositions include paints intended to provide protective 
surfaces. 
The reason for the widespread use of asbestos is that it is the only 
natural mineral which combines a number of important properties in one 
material; particularly asbestos produces the following properties when 
incorporated in binder-containing compositions in appropriate amounts: 
A. produces rapid thickening 
B. produces short-bodied consistency 
C. produces good spreadability or knifability 
D. produces good homogeneity 
E. prevents internal slippage 
F. produces a composition of stable consistency 
G. imparts good weatherability 
H. reinforces coatings and self-supporting sheets produced from the 
composition. 
In addition asbestos has the advantage that it is low in cost, and the 
disadvantage that it promotes internal oxidation of the compositions which 
may result in deterioration. 
Recently asbestos has been exposed as a carcinogenic substance causing 
asbestosis, a lung disease that often develops into cancer of the 
respiratory system. A world wide medical attack has been launched 
triggering governmental controls in the handling of asbestos at the mines 
as well as in industries which use or process asbestos. Such controls may 
cost industries millions of dollars, for example, in the installation of 
air purifying equipment, which ultimately will result in higher prices of 
asbestos-containing products to the consumer. Further medical research may 
even cause governments to ban the use of asbestos in consumer products 
such as floor tiles and sealants. 
It is clearly highly desirable to find an alternative to asbestos fibres 
which will produce the desirable physical characteristics in compositions 
which are characteristic of asbestos-containing compositions. 
It is an object of this invention to provide an alternative to asbestos as 
a reinforcing and thickening agent in a variety of compositions, which 
alternative does not display the hazards associated with the use of 
asbestos. 
It is a further object of this invention to provide a variety of 
compositions including moldable and trowellable compositions and brushable 
and sprayable compositions containing an organic fibrous reinforcing and 
thickening agent. 
It is yet another object of this invention to provide self-supporting sheet 
products containing an organic fibrous reinforcing and thickening agent. 
It is still a further object of this invention to provide a coating 
containing an organic fibrous reinforcing and thickening agent. 
SUMMARY OF THE INVENTION 
According to the invention there is provided a composition comprising an 
organic binder in a liquid vehicle having dispersed therein a thickening 
and reinforcing amount of an amorphous, fibrous, cellular, absorbent 
organic material. 
The liquid vehicle is suitably a solvent for the organic binder; however, 
it is also possible to employ a liquid, for example, water, in which the 
organic binder can be emulsified suitably with appropriate emulsifying 
agents. 
The compositions of the invention may contain a wide variety of ingredients 
of a conventional nature, depending on the intended utility of the 
composition, for example, pigments, dyes, inert fillers, driers, 
hardeners, catalysts, tackifiers, extenders and plasticizers. 
The compositions of the invention may be provided as moldable or 
trowellable compositions or as brushable or sprayable compositions 
depending on the specific ingredients and their relative amounts, having 
regard to the desired application of the composition. 
According to another aspect of the invention there is provided a coated 
substrate in which the coating comprises a film-forming organic binder 
containing a reinforcing amount of an amorphous, fibrous, cellular, 
absorbent, organic material. 
According to yet another aspect of the invention there is provided a 
self-supporting sheet comprising a sheet forming organic binder containing 
a reinforcing amount of an amorphous, fibrous, cellular, absorbent, 
organic material. 
DESCRIPTION OF THE PREFERRED EMBODIMENT 
Fibrous Material 
The fibrous material employed in the invention is a synthetic organic 
amorphous, fibrous, cellular material which is highly absorbent. 
The physical structure of the fibrous material is capable of high 
adsorption or absorption of the organic binder in its liquid vehicle 
producing a thickened short-bodied composition stable to vibration, 
stirring, slump, spraying, trowelling and other mechanical disturbances. 
In this respect it appears that the high absorption and adsorption 
characteristics attract some of the binder establishing a bonding system 
similar to steel reinforcing in concrete; and external forces applied to 
the reinforced binder do not easily cause deformation and rupture of the 
binder. 
Manufacture of Urea-Formaldehyde Fibrous Material 
A particularly preferred fibrous material is obtained by shredding or 
otherwise disintegrating a cellular plastic produced by foaming a 
water-soluble urea-formaldehyde pre-condensate. The cellular plastic is 
suitably produced from an aqueous solution of the urea-formaldehyde 
pre-condensate and an aqueous solution of a foaming agent. The foaming 
agent solution is foamed by stirring or by introducing compressed air, for 
example, as described in German Pat. No. 636,658 I. G. Farben of Dec. 29, 
1933, and the aqueous solution of the urea-formaldehyde pre-condensate is 
added to the foam and thus assumes the cellular structure. Suitable 
foaming agents include alkyl naphthalene sulphonic acids, for example 
butyl naphthalene sulphonic acid, and other weak sulphur-acids. 
The urea-formaldehyde pre-condensate is suitably that available under the 
trademark Resin 293 Powder from Badische Anilin- & Soda-Fabrik AG and is 
usually processed in the form of a 38% aqueous solution (38 pts. wt. Resin 
293 Powder in 62 pts. wt. water) which is allowed to mature for 15-20 
hours before use. 
The foaming composition is suitably Foaming Agent 514 Liquid or Foaming 
Agent 400 Liquid, both trademarks of Badische Anilin- & Soda-Fabrik AG. 
Foaming Agent 514 Liquid is an aqueous solution of a cross-linking agent 
with a high foaming and emulsifying capacity and contains phosphoric acid 
for curing Resin 293 Powder. 
Foaming Agent 404 Liquid is an aqueous solution of a synthetic 
cross-linking agent without curing action; it is suitable where an 
acid-free foaming agent is required. 
These agents are described by the manufacturer and supplier, Badische 
Anilin- & Soda-Fabrik AG as having the following characteristics. 
TABLE I 
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Properties Resin 293 Powder 
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Colour white 
Bulk density 600 - 800 g/l 
Moisture content.sup.1 
max. 2% 
Water tolerance.sup.2 
1:3 to 1:4,5 
Free formaldehyde.sup.3 
7.5 - 8.5% 
Storage stability at 20.degree. C 
1 year 
Storage stability of 38% 
solution at 20.degree. C 
approx. 12 weeks 
Density of the 38% solution 
at 20.degree. C 1.15 - 1.16 g/cm.sup.3 
Free formaldehyde in the 38% 
solution 3 -4% 
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.sup.1 With xylene according to Aufhauser. 
.sup.2 Water is added in small portions at 20.degree.C to a 38% solution 
of the resin until the resin commences to flocculate. The total amount of 
water is expressed in terms of the solid resin. 
.sup.3 Cool 1 g of Resin 293 Powder + 5 g ethanediol to 5.degree. C and 
add 20 ml of a 25% neutral Na.sub.2 SO.sub.3 solution. Keep the mixture 
for 20 minutes at 5.degree. C and then titrate with n-H.sub.2 SO.sub.4 
using phenolphthalein as indicator. 
TABLE II 
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Properties Foaming Agent 514 Liquid 
______________________________________ 
Foaming Agent 514 Liquid 
is a dark brown aqueous 
solution. 
Density at 20.degree. C 
1.23 - 1.24 g/cm.sup.3 
pH.sup.4 0.7 .+-. 0.2 
Storage stability unlimited 
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.sup.4 Glass electrodes. Determined after dilution with 10 parts by volum 
water. 
TABLE III 
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Properties Foaming Agent 404 Liquid 
______________________________________ 
Foaming Agent 404 Liquid 
is a dark brown aqueous 
solution. 
Denity at 20.degree. C 
1.04 - 1.05 g/cm.sup.3 
pH.sup.4 7 - 8 
Storage stability unlimited 
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.sup.4 Glass electrodes. Determined after dilution with 10 parts by volum 
water. 
In manufacturing the fibrous urea-formaldehyde product the foaming agent 
(Foaming Agent 514 Liquid) is first thinned with water and then foamed by 
stirring or by compressed air. An aqueous solution, suitably a 38% aqueous 
solution of the urea-formaldehyde pre-condensate is added to the foam and 
at 20.degree. C sets in about 10 to 60 seconds to a water-insoluble 
substance with a fine cellular structure. The setting time can be 
shortened by employing solutions at higher temperatures or by heating the 
air used for foaming. Further the setting time may be affected by the 
hardness and composition of the water used for thinning. The setting time 
can be further shortened by the addition of 1-2% of 70% phosphoric acid 
(technical) to the foaming agent solution. The setting time is longer with 
Foaming Agent 404 Liquid. 
After setting condensation of the foam takes place in 2 to 4 hours and the 
condensed mass is dried to remove water. 
The foaming is suitably controlled to produce a water-insoluble cellular 
product having a density of 0.4 to 0.7 lbs/cu. ft. with about 60% closed 
and 40% open cells. The foam shows evidence of some shrinkage, up to about 
7% with fast drying but with slow drying shrinkage can be controlled to 
less than 1%. The cellular product is resilient but will give under loads 
exceeding about 0.2 lbs/sq.in. and is mechanically shredded or ground to a 
loose mass of multi-branched, feather-like fibres resulting from the 
cross-linked structure of the cellular product. 
Physical Characteristics of Urea-Formaldehyde Fibrous Material 
The fibrous cellular urea-formaldehyde material has a complex microscopic 
structure of closed and open cells interspersed with irregular and 
discontinuous capillaries, which gives the fibrous material adsorbent and 
absorbent properties. 
Under a microscope at a magnification of 10 the fibrous material appears as 
a fluffy, white amorphous mass loosely agglomerated like absorbent cotton. 
At a magnification of 40 the fibrous material is transparent and made up 
of clumps 2 to 15 microns in diameter, interspersed with capillary 
tube-like particles or filaments from 5 to 50 microns in length. These 
"capillaries" occur as straight tubes with an external diameter up to 5 
microns with thin transparent walls as well as L-shaped and Y-shaped 
tubes. The capillaries can be separate or they can be clumped together. 
In order to retain the absorbent and reinforcing properties of the fibrous 
material it appears to be necessary to retain the fibrous capillary 
structure. This fibrous capillary structure is adequately retained when 
the foamed cellular product is ground to the above described dimensions. 
It is possible that adequate absorbing and reinforcing properties might be 
retained with dimensions outside these ranges, however, if the foamed 
cellular product is ground to a fine non-absorbent powder it will possess 
little if any reinforcing properties. 
The fibrous materials may also have adsorbent properties which will enhance 
the thickening effect. However the absorbent property is more significant 
than the adsorption property. 
The fibrous urea-formaldehyde material has a number of desirable 
characteristics which make it highly suitable as a thickening and 
reinforcing agent for the compositions of the invention and which make it 
advantageous over the use of asbestos. 
i. the fibrous material is lipophilic (oleophilic) having an affinity for 
oils and substances that usually repel water. 
ii. the fibrous material is hydrophobic displaying strong water repellency 
and does not absorb or retain water; it is also water-insoluble. 
iii. the fibres of the fibrous material are apparently flexible and do not 
break easily when subjected to mechanical forces such as are produced in 
compression, agitation, mixing, trowelling and spraying. 
iv. the fibrous material has a high melting point and melts at about 
428.degree. F, at 1,800.degree. F it will carbonize; further it does not 
retain heat and can be considered non-burning or self-extinguishing; these 
properties make it suitable in high temperature applications. 
v. the fibrous material is light-weight and colourless and can be used in 
clear compositions. 
vi. the fibrous material is resistant to solvents such as petroleum 
distillates and coal tar derivatives. 
vii. the fibrous material is non-toxic and is not carcinogenic like 
asbestos; when subjected to radiant heat or a flame of 1,300.degree. F it 
decomposes releasing water vapour, oxygen, carbon dioxide and minor 
amounts of carbon monoxide and amines. 
viii. the fibrous material is synthetic and made from readily available raw 
materials and can be made as desired throughout the world. 
ix. the fibrous material can produce a thickening effect two to three times 
greater than a corresponding amount of asbestos, and is thus more 
economical. 
xi. the fibrous material improves flow resistance at high shear rates since 
it acts as a thickening agent. 
xii. the fibrous material is wet rapidly by oils and the like and thus 
disperses rapidly. 
xiii. the fibrous material is not dusty. 
xiv. the fibrous material is highly absorbent and this is responsible for 
many of its desirable characteristics. 
xv. the fibrous material is mildly bactericidal and resists the common 
molds of the genus Mucor, Aspergilli and Alternaria. 
The fibrous material is found to be compressible and can be compressed in a 
compression bagging machine and packaged in paper or plastic bags for 
shipment. The compression, due to the high resilience of the fibrous 
material, does not alter the structure or physical characteristics. Since 
the physical configuration is not altered by this compression, the fibrous 
material is easily dispersed by simple mechanical shearing action into the 
composition. 
Other Fibrous Materials 
Although particular attention has been given to the especially preferred 
urea-formaldehyde fibrous material other fibrous materials of similar 
physical structure and properties can also be employed in the compositions 
of the invention. In particular there may be mentioned those foamable 
condensation products chemically similar to urea-formaldehyde including 
melamine-formaldehyde, melamine urea-thiourea condensation products with 
formaldehyde, thiourea-formaldehyde and phenol-formaldehyde. Similarly 
other resin materials, plastics and polymers capable of being foamed to 
cellular, fibrous products with absorption properties such as are produced 
by capilliaries in the fibrous products can be employed. 
Organic Binder 
A wide variety of organic binders can be employed in the compositions of 
the invention depending on the particular application. 
It will be recognized that the expression "organic binder" is employed in a 
generic sense to embrace different kinds of material. The binders will 
have different physical properties depending on the utility of the 
composition, but all will be solid substances which are solidifiable from 
the compositions to form a hard connecting medium between the fibrous 
material and other solid materials, for example, fillers which may be 
included in the composition. 
In the case where the composition is a sealant or caulking composition the 
binder will be a generally adhesive material which partially hardens and 
retains its form; suitably the compositions form a hard, flexible skin on 
exposure to the air, the inner portion remaining pliable. 
In the case where the composition is to be used to form a coating the 
organic binder will be selected from film forming organic materials which 
are solidifiable to form hard coatings. 
Suitable binders include, bitumens; asphalts; pitches; natural and 
synthetic resins; natural and synthetic polymers; natural and synthetic 
rubber; styrene-butadiene rubbers; butyl rubbers, neoprene; Hycar 
(trademark) synthetic rubbers manufactured by B. F. Goodrich Chemical Co., 
including butadiene-acrylonitrile copolymers and acrylic acid ester 
polymers; acrylics, vinyls, styrenes, propylenes, polyurethanes, vegetable 
and animal oils and other binder substances commonly used for coatings, 
paints, vapour barriers, sealants, caulking compositions, mastics and 
putties. 
Liquid Vehicle 
The liquid vehicle is suitably a solvent for the organic binder. Volatile 
solvents are preferred since they are more readily removed after 
application of the composition by evaporation at room temperature; 
however, the liquid vehicle may similarly be removed by heating or forced 
air circulation. 
The liquid vehicle chosen in any particular case will, of course, be 
dependent on the particular binder. 
Liquid vehicles in which the binder is only partially soluble or insoluble 
can also be employed providing the binder can be dispersed, solubilized or 
otherwise introduced. 
Liquid vehicles within the scope of the invention include bunker fuel oil; 
kerosene; high-flash straight petroleum aliphatic solvents such as those 
available under the trademark Varsol from Humble Oil & Refining Co.; light 
mineral spirits; naphtha; rubber solvents; hexane; pentane; coal tar 
distillates including xylene, toluene and benzene. 
The liquid vehicle may also be water or other liquids in which the binder 
can be dispersed or emulsified using dispersing and emulsifying agents, 
soaps and synthetic surface active agents. To produce the dispersions or 
emulsions there are suitably employed colloid mills, high speed dispersers 
or shear-type equipment, for example Baker-Perkins, Bowers, Cowles and 
Charlotte mills. 
Compositions 
The amount of fibrous material included in the compositions will vary 
according to the intended use; suitably the fibrous material is employed 
in an amount of 1 to 30%, preferably 5 to 25% and more preferably 10 to 
20%, by weight, of the binder. 
The amount of liquid vehicle employed will be determined by the amount 
necessary to get the binder into solution, emulsion or dispersion as the 
case may be. 
A part of the fibrous material may be replaced by other fibres including 
natural and synthetic staple fibres, for example, wool, rayon, nylon, 
polypropylene, phenol-formaldehyde, polyesters, cotton, sisal and other 
substances that can be formed into monofilaments and cut to an appropriate 
length for incorporation in the composition of the invention as 
reinforcing agents. The percentage of these fibres employed will be 
dependent upon the end product. However, these fibres alone are not 
satisfactory since they do not have the required liquid absorbent 
properties resulting from the intermeshed, feather-like structure. 
As described the fibrous material can be employed in a variety of 
compositions within the scope of the invention; and the particular binders 
and liquid vehicles and the relative amounts of the ingredients will 
depend upon the kind of composition desired. 
Depending on the particular composition, there may also be included a 
variety of conventional additives including fillers and extenders, for 
example, carbonates, silica, silicates, oxides, clays, carbon black, mica 
and barytes; pigments, for example, oxides and salt of zinc, iron, lead, 
titanium, calcium, magnesium and metal flakes; dyes, antioxidants, 
plasticizers, thickeners, stabilizers, softeners, hardeners, dispersing 
agents, drying agents, oxidizing agents and suspension agents. 
The compositions of the invention include, for example, sealants and 
cements wherein the composition may be molded or trowled into a cavity; 
and coating compositions for producing coated surfaces, comprising a 
film-forming binder with fibrous material therein. The compositions may 
similarly be molded into self-supporting products comprising a continuous 
sheet of the binder with the fibrous material dispersed therein as a 
reinforcement, for example, asphalt or vinyl tiles.

EXAMPLES 
A conventional plastic cement or roofing cement is one having the following 
formulation, by weight. 
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Straight run or blown asphalt cutback 
65% solution in mineral solvent 
59 
Crude limestone dust (grey) 
18 
Mineral solvent, 100.degree. F flash, min 
app. 300.degree. F to 400.degree. F boiling range 
5 
Asbestos fibre: 7R or 7T 
18 
100 
Grease Cone Penetration 77.degree. F 
150 gm. total weight about 300 1/10 mm. 
______________________________________ 
A similar composition can be prepared following the teachings of the 
invention but employing a significantly lesser amount of urea-formaldehyde 
fibrous material than asbestos. 
______________________________________ 
Straight run or blown asphalt cutback, 
65% in mineral solvent 51.5 
Crude limestone dust (grey) 
39.5 
Mineral solvent, 100.degree. F flash, min. 
app. 200.degree. F to 400.degree. F boiling range 
4.1 
Urea-formaldehyde fibrous material 
4.9 
100.0 
Grease Cone Penetration 77.degree. F 
150 gm. total weight: about 300 1/10 mm. 
______________________________________ 
A lesser amount of urea-formaldehyde fibrous material was necessary since 
it has higher thickening and reinforcing properties than asbestos. 
Both the asphalt-containing composition and the compositions of the 
invention were made by the same method detailed below. 
The asphalt was measured into a paddle or ribbon type mixer having a 
capacity of about 600 Imperial Gallons and was slowly mixed; the crude 
limestone was added to the asphalt during the slow mixing and mixing was 
continued at a low speed of about 30 r.p.m. for 5 minutes. 
The fibrous material was added slowly and the mixing was continued at low 
speed for about 10 minutes. 
The mixer was stopped and a liter sample was drawn from the mixture. The 
sample was adjusted to a temperature of 77.degree. F, stirring constantly 
by hand. A portion of the sample at 77.degree. F was introduced into a 
brass grease cup which had previously been brought to a temperature of 
77.degree. F in a controlled temperature bath. 
The consistency of the material was read on the penetrometer and three 
consecutive readings were made and averaged out. 
If the desired consistency was not reached (300 to 350 depending upon the 
season) more mineral solvent was added to the mixer and the mixture mixed 
for a further 5-minute period after which the consistency was again 
tested; this was repeated until the desired consistency was obtained. 
The quantity of mineral solvent in the composition is variable from 1 to 
10% and is dependent upon the consistency of the cutback, the absorption 
characteristics of the limestone and the fibrous material and the desired 
consistency in the end product. 
The relative amounts of the various ingredients can of course, be varied 
considerably depending on the desired characteristics.