A BINDER SUBSTANCE

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.

Description: A Binder Substance The present invention relates to a binder βubstance intended primarily for binding finely divided, dust-generating solid material and also intended to be applied in the form of an aqueous phase, e.g. sprayed onto a dust source and therewith bind dust and to be stabilised as the water vapour disperses, such as to form a binding film. Dusty environments create serious problems in present times, not least in industry. One special problem in this respect is encountered in places where dust-generating material is stored, among other things because of the large quantities of dust available. It is therewith desirable to bind the dust mechanically and also to passivate the dust in a manner to avoid undesirable leaching phenomenon. Binding substances for this purpose are known to the art. See, for instance, Swedish Patent No. (Swedish Patent Appli¬ cation 8503765-3), which relates to technique providing good dust- binding ability. The present invention, however, relates to a binding substance which possesses an extremely high dust-binding capacity and which is effective over considerably long periods of time, as compared with known techniques. This renders the inventive Bubstance suitable for treating, inter alia, sites intended for the long-term storage of dust-generating material. Thus, the present invention relates to a binding substance intended primarily for finely-divided, dust-generating solid material. The binding substance is in the form of an aqueous emulsion and/or aqueous solution and is intended to be applied, such as sprayed, onto a dust source and therewith bind dust, and to be stabilized by the dis¬ persion of water, such as to form a binding film. The inventive binder substance is characterized particularly in that it includes at least one polymer-based substance in combination with fibres operative to form a reinforcement in the film. The invention will now be described in more detail with reference to exemplifying embodiments thereof. According to one preferred embodiment of the inventive binder sub¬ stance, the polymer-based substance is a polyvinyl alcohol in aqueous solution, a preferred concentration of polyvinyl alcohol being about 1-10* by weight. A suitable polyvinyl alcohol is one that has a high degree of hydrolysis and long molecular chains, with the purpose of reducing solubility in water and increasing weather resistance. An example of a polyvinly alcohol suitable in the present context is a quality having a hydrolysis degree of 99.7 ± 0.3 mol-*. The fibres are preferably cellulose fibres, preferably cellulose fibres comprising substantially unbleached paper pulp. A preferred fibre concentration is about 1-15* by weight. With the intention of being able to vary or adapt the binder substance to the properties of the substrate surface, i.e. the dust source, a viscosity-elevating substance can be supplied to and incorporated in the binder substance. The viscosity-elevating substance may be mixed directly with the binder substance, prior to applying said substance, e.g. spraying said substance, and/or can be mixed with the substance in conjunction with its application, e.g. by spraying, the viscosity- elevating substance being pre-applied, e.g. pre-sprayed, onto the dust source. The viscosity-elevating substance is thus operative to increase the viscosity of the binder substance to a desired extent, therewith to provide a product of more solid consistency, a gel. The viscosity-enhancing substance may, of course, comprise two or more individual substances. According to one embodiment, the viscosity- enhancing substance comprises one or more of the substances boric acid and salts thereof. The element-groups 4, 5 and 6 of the periodic table may also be used as viscosity-enhancing substances, and also chemical compounds containing these elements. The following composition is given by way of example: 1 kg 5*-aqueous solution of polyvinyl chloride 65 g CTMP (unbleached pulp fibre) The components are thoroughly mixed. The function performed by the inventive binder substance will be evident to a large extent from the aforegoing. The polymer-based sub¬ stance is mixed with fibres and, when appropriate, with a viscosity-enhancing substance. Thus, when applied to the substrate surface 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 less pronounced gel character. This product then dries to form a stable film, which will not redissolve. The resultant film is swellable in water and will soften slightly when exposed to water over longer periods »of time, such as during a prolonged period of rain, but will dry as soon as watering of the film ceases. As will be understood 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 substance is influenced very slowly by outdoor environments and the like. The durability of the binder substance is influenced by the substrate surface and the thickness to which the layer is applied. The material beneath the binder substance, the film, is kept dry, i.e. protected from rain, therewith preventing leaching, which is essential when the material contains environmentally harmful sub¬ stances. The diffusion of gas can take place slowly through the film. The film, however, is sufficiently dense to make rapid combustion of the material covered by the film impossible. Slower processes, 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 classified as safe goods for transport purposes. The invention has been described in the aforegoing with reference to an exemplifying embodiment thereof. It will be understood, however, that other embodiments and minor modifications can be made without departing from the inventive concept. For instance, polymer-based substances other than polyvinyl alcohol can be used as an alternative. Emulsions or suspensions of one or more of the following substances can also be used: - ' Polyvinyl acetate - Polystyrene - Co-polymers of, e.g. vinyl acetate, ethylene and vinyl chloride - Polyacrylate The proportions of polymer-based substances preferably being about 25-60* by weight. Since a non-wetting layer of binder substance is most often desired, it is conceivable to include in the binder substance at least one surface-tension enhancing substance, such as a so-called foam-damping substance. With regard to the reinforcing fibres, organic fibres are preferred, such as cellulose fibres. Other fibres, such as textile or peat fibres are also conceivable. The invention is therefore not restricted to the aforedescribed embodiments, since modifications and variations can be made within the scope of the following Claims.

Claims: 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 fibreβ 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 Bubstance 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. 9. A substance accordingv to Claim 7 or 8, 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.

Inventors: BERGMARK PONTUS, SAHLEN SIGVARD, BERGMARK, PONTUS, SAHLEN, SIGVARD
Applicants: SAHLEN SIGVARD, SAHLEN, SIGVARD
Application year: 1990
Main classification: C09K3
IPC codes: C09K3