LIANT

BINDER SUBSTANCE

Abrégé anglais

Abstract
A binder substance intended primarily for binding finely-divided,
dust-generating solid material. The binder substance is in the form
of an aqueous emulsion and/or aqueous solution and is applied to,
e.g. sprayed onto, a dust source therewith binding dust, and stabilizes
to form a binding film through the dispersion of water.
The substance is mainly characterized in that it includes at least
one polymer-based substance in combination with fibres which are
operative to reinforce the film.

Revendications

WO90/10042 PCT/SE90/00127
Claims
1. A binder substance intended primarily to bind finely divided,
dust-generating solid material, and intended to be applied, e.g.
sprayed, in the form of an aqueous emulsion and/or an aqueous solution
onto a dust source, therewith to bind dust, and to stabilize through
the departure of water such as to form a binding film, c h a r a c -
t e r i z e d in that the binder substance includes at least one
polymer-based substance in combination with fibres intended to form a
reinforcement in the film.
2. A substance according to Claim 1, c h a r a c t e r i z e d in
that it includes a polyvinyl alcohol in aqueous solution.
3. A substance according to Claim 2, c h a r a c t e r i z e d in
that the concentration of polyvinyl alcohol in said aqueous solution
is about 1-10% by weight.
4. A substance according to Claim 1, 2 or 3, c h a r a c -
t e r i z e d in that the fibres are cellulose fibres.
5. A substance according to Claim 4, c h a r a c t e r i z e d in
that the cellulose fibres are essentially unbleached paper pulp.
6. A substance according to Claim 1, 2, 3, 4 or 5,
c h a r a c t e r i z e d in that the fibre concentration is about
1-15% by weight.
7. A substance according to Claim 1, 2, 3, 4, 5 or 6,
c h a r a c t e r i z e d in that it includes a viscosity-enhancing
substance.
8. A substance according to Claim 7, c h a r a c t e r i z e d in
that the viscosity-enhancing substance is added by direct admixture
prior to applying the binder substance and/or by mixture in conjunction
with application, the viscosity-enhancing substance being pre-applied
on the dust source.

WO90/10042 PCT/SE90/00127
9. A substance according to Claim 7 or a, c h a r a c t e r -
i z e d in that the viscosity-enhancing substance comprises one or
more of the substances boric acid and salts thereof.
10. A substance according to any one of the preceding claims,
c h a r a c t e r i z e d in that it includes a surface-tension
increasing substance, such as a so-called foam-damping substance.

Description

W O 90/10042 PCT/SE90/00l27
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A ~inder Substance
The present invention relates to a binder substance lntended primarily
for binding finely divided, du~t-generating solid material and al00
intended to be applied in the form of an aqueous pha~e, e.g. sprayed
onto a dust source and therewith bind dust and to be stabili~ed as
the water vapour di~perses, such a~ to form a binding film.
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Dusty environments create serious problem3 in pre~ent times, not
lea~t in industry. One special problem in this re~pect i~ encountered
in places where dust-generating material i9 3tored, among other
things because of the large quantities of du3t available. It i~
therewith desirable to bind the dust mechanically and al90 to passivate
the dust in a manner to avoid undeairable leaching phenomenon.
~inding 3ubstances for thi~ purpo~e are known to the art. See, for
instance, Swedish Patent No. tSwedish Patent Appli-
cation 6503765-3), which relates ~o technique providing good dust-
-; binding ability. The present invention, however, relates to a binding
substance which po~esses an extremely high dust-binding capacity and
which is effective over con~iderably long periods of time, as compared
with known technique3. This render~ the i.nventive 3ub3tance ~uita~le
for treating, inter alia, sites intended for the long-term ~torage of
dust-qeneratinq material.
Thus, the pre~ent invention relate~ to a binding ~ubstance intended
primarily for finely-divided, du~t-generating ~olid material. The
binding subqtance is in the form of a~ aqueous emulsion and/or aqueou~
solution and is intended to be applied, such as sprayed, onto a du~t
source and therewith bind dust, and to be ~tabilized by the dis-
persion of water, such as to form a binding film.
The inventive binder substance is characterized particularly in that
; it include~ a~ least one polymer-ba~ed substance in combination with
fibres operative to form a reinforcement in the film.
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The inventlon will now be described in more detail with reference to
exemplifying embodiment~ thereof.
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WO 90/10042 PCI/SE90/00127
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According to one preferred embodiment of the inventive binder sub-
stance, the polymer-based substance i~ a polyvinyl alcohol in aqueou~
solution, a preferred concentration of polyvinyl alcohol being about
1-10% by weight. A suitable polyvinyl alcohol i9 one that has a high
- degree of hydrolysi~ and long molecular chain~, with the purpose of
reducing solubility in water and increa~ing weather resistance. An
example of a poly~inly alcohol suitable in the present context i9 a
quality having a hydrolysis degree of 99.7 ~ 0.3 mol-X.
~ The fihres are preferably celluloYe fibres, preferably cellulo3e
- fibre~ comprising substantially unb~eached paper pulp. A preferred
fibre concentration i8 ahout 1-15X by wei~ht.
,:
With the intention of being able to vary or adapt ~he binder substance
to the propertie~ of the substrate surface, i.e. the dust source, a
viscosity-elevating sub~ance can be supplied to and incorporated in
~ the binder ~ubstance. The viscosity-elevating ~ubstance may be mixed
; directly with the binder substance, prior to applyin~ said ~ub~tance,
e.g. spraying said sub3tance, and/or can be mixed with the substance
in coniunction with its application, e.g. by spraying, the viscosity-
elevating ~ub~tance being pre-applied, e.g. pre-~prayed, onto the
dust source. The vi~cosi~y-elevating ~ubstance i5 thus operative to
: increase the viscosity of the binder substance to a desired extent,
;~ 25 therewith to provide a product of more solid consistency, a gel.
The visco~ity-enhancing substance may, of cour~e, compriae two or
- more individual ~ubstances. According to one embodiment, the vi~c08ity-
; enhancing ~ubstance comprises one or more of the substances boric
acid and ~alts thereof. The element groups 4, 5 and 6 of the periodic
table may also be u3ed a~ visco~ity-enhancing ~ubstances, and also
: chemical compounds containing these elements.
The following compo~ition is given by way o~ example-
1 kg 5X-aqueous ~olution of polyvinyl chloride
65 g CTMP ~unbleached pulp fibre)
T~e components are thoroughly mixed.
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W O 90/10042 PCT/SE90/00l27
3 ~72~
The function performed by the inventive binder ~ub~tance will be
evident to a large extent from the aforegoing. The polymer-based sub-
gtance i9 mixed with fibre3 and, when appropriate, with a
S viscosity-enhancing substance. Thus, when applied to the substrate
~urface concerned, the dust source, the binder substance will forM a
more or less solid product, depending on the mixture of viscosity-
enhancing substance, i.e. a product having a more or le~s pronounced
gel character. This product then dries to form a stable film, which
;10 will not redis301ve. The resultant film i9 swellable in water and
-will ~often slightly when exposed to wa~er over lDnger periods of
time, such as during a prolonged period of rain, but will dry as soon
as wateriny of the film ceases.
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As will be under~tood from the aforegoing, the inventive binder
substance provides a very suitable solution to the problem of elimin-
ating the harmful effect of dust~generating material. The binder
reinforcement provides a strong and tough covering surface. The
binder sub3tance i9 influenced very slowly by outdoor environments
and the like. The durability of the binder substance i9 influenced by
~:the ~ubstrate surface and the thickness to which the layer i~ applied.
The material beneath the binder substance, the film, i9 kept dry,
i.e. protected from rain, therewith preventing leaching, which i9
essential when the material contain~ environmentally harmful sub-
~tances. The diffusion ~f gas can take place 810wly through the film.
The film, however, is sufficiently dense to make rapid combu~tion of
the material covered by the film impossible. Slower proce~ses, such
as fermentation, however, can proceed beneath the film.
In the case of combustion, the binder substance produces carbon-
dioxide and water and can be handled safely both in a wet and a dry
state, and is cla~sified a~ ~afe goods for transport purposes.
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The inventlon ha~ been described in the aforegoing with reference to
an exempllfying embodlment thereof. It will be understood, howeYer,
that other embodiments and minor modlfications can be made without
departing from the inventive concept.
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W O 90/10042 PCT/SE90/00127
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~72~
For instance, polymer-based substances other than polyvinyl alcohol
can be u~ed as an alternative. Emulsions or ~u~pension3 of one or
more of the followiny sub~tances can also be used:
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- Polyvinyl acetate
- Polystyrene
- Co-polymers of, e.g. vinyl acetate, ethylene and vinyl chloride
- Polyacrylate
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The proportions of polymer-based ~ubstances pre~erably being about
25-60~ by weight.
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Since a non-wetting layer of binder ~ubstance i~ most often desired,
it is conceivable to include in the binder substance at least one
surface-tension enhancing ~u~stance, such as a ~o-called foam-damping
substance.
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With regard to the reinforcing fibres, organic fibre~ are preferred,
such as cellulose fibres. Other fi~res, ~uch as textile or peat
.' fibres are also conceivable.
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The invention i9 therefore not restricted to the aforedescribed
embodiments, since modifications and variations can ~e made within
the 3cope of the following Claim~.
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