Method for manufacturing a binder and use thereof

Details Method for manufacturing a binder and use thereof Method for manufacturing a binder and use thereof

2001-03-28

2003-07-29

Yao, Sam Chuan (Department: 1733)

Adhesive bonding and miscellaneous chemical manufacture

Methods

Surface bonding and/or assembly therefor

C156S062200, C264S128000, C516S078000, C516S081000

Reexamination Certificate

active

06599388

ABSTRACT:

FIELD OF THE INVENTION
The object of the present invention is a method for making a binder by using, as the starting material, a particulate mineral material with a glassy amorphous structure, especially a waste material from mineral wool production. Such a binder is suitable for binding mineral materials, especially for use as a binder in the manufacture of mineral wool products from mineral fibres. Another object of the present invention is a method for manufacturing mineral wool products using the said binder for binding the mineral fibres.
BACKGROUND OF THE INVENTION
(Mineral fibres made by melting and centrifuging of mineral raw materials, such as stone, slag, glass, ceramics or the like,) are extensively used for the manufacture of mineral fibre mats and blankets, primarily for heat and sound insulation purposes, especially within the construction industry. Such mineral fibre products conventionally contain a binder, of which a number of different types are known.
Thus for example phenol cured insulating products are known. Phenol is a fairly inexpensive and also a rapidly curing binder. A phenol cured product resists temperatures up to 250° C., but the bonds are destroyed if the temperature is maintained above 250° C. for an extended period of time. At higher temperatures, at 400° C. and more, the binder loses its strength, the temperature increases rapidly and the product collapses. In addition, a phenol cured insulating product emits poisonous gases during burning. An additional and also major disadvantage is that the presence of phenol in the product will cause an undesired load on the environment when the binder-containing mineral wool product is to be disposed of after use.
Also water glass has been widely used as a binder. Water glass is traditionally made by melting silica sand with sodium or potassium carbonate at a very high temperature and then dissolving the finely divided solidified product in water. Thus water glass can be considered an ecologically acceptable substance to include as a binder e.g. in mineral wool products. A disadvantage is, however, that the manufacture thereof uses pure raw materials and is energy consuming.
It is also known to use a mixture of water glass and clay as a binder for mineral wool products, see e.g. SE 420 488. Such a product, although providing good water and heat resistance, has poor compression resistance, is brittle and causes dusting. The EP B 466 754 on the other hand describes the use of a binder made from slag and water glass for making a temperature and moisture resistant mineral wool product which is also capable of withstanding high temporary loads.
SUMMARY OF THE INVENTION
The object of the present invention is to provide an easy and economically feasible method for obtaining a binder, which has excellent binding and fire resistant properties and is acceptable from a use or labour hygiene point of view. In addition, the binder according to the invention can be manufactured from inexpensive and easily available raw materials, or by-products, in a simple manner. An important advantage is that the binder made according to the invention presents no excessive ecological load on the environment, but contains only such components that are already inherently present in nature.
The object of the present invention is thus a method for making a binder comprising the steps of
(dissolving a particulate mineral material having a glassy amorphous structure in an aqueous solution to form a solution containing nucleated re-precipitated particles from the material,)
stabilizing the so obtained solution to (form a sol) having a desired particle size, and optionally
adjusting the dry matter content of the sol.
The starting material for the binder can be a mineral wool material, especially a recirculated waste material from mineral wool production, as will be described in more detail below.
Another object of the present invention is a method for the production of a mineral wool product using the binder prepared according to the invention by contacting the binder with mineral fibres in order to bind the fibres to form a mineral wool product.
DETAILED DESCRIPTION OF THE INVENTION
According to a preferred embodiment of the invention, the particulate mineral material is a waste mineral wool product obtained from mineral wool production. Such waste material is formed in large quantities, typically up to 20-30% by weight of the starting raw material, in the form of spinning waste, unused fibers of rejected fibrous products (pre-consumer products). One applicable source for the material is also different constructions which will be taken down and in which mineral wool material has been used for instance as heat insulation (post-consumer products). Such a waste material is already in finely divided, typically fibrous form and can thus be used as such, or alternatively it can also be divided to an even finer form to provide a product with a large surface area, such as 0.4 m
2
/g or larger, e.g. up to 25 m
2
/g and thus has good dissolution properties in the aqueous solution. Fibres obtained from mineral wool production typically have a diameter of 0.5 to 20, usually 2 to 15 &mgr;m, preferably 3 to 5 &mgr;m as measured with OM or SEM using a suitable method (e.g. Koenig et al, Analytica Chimica Acta 1993 280 289-298; Christensen et al, AM IND HYG ASSOC (54) May 1993), and a length of 0.5 to 50, usually 2 to 20 mm, preferably 3 to 10 mm.
The aqueous solution can be an alkaline solution, such as an alkali metal or earth alkali metal hydroxide, carbonate or hydrocarbonate solution, especially a sodium, potassium or lithium hydroxide solution, or an ammonium hydroxide solution. Such a solution is preferably 0.1 to 2 molar with respect to the alkaline agent, or has a pH of 10 to 14, in order to easily dissolve also such mineral raw materials which are poorly soluble in neutral solutions.
The aqueous solution can also be an acidic solution, such as an aqueous solution made acidic by adding an inorganic or organic acid, such as HCl, HNO
3
, H
2
SO
4
, H
3
PO
4
, formic, acetic, propionic acid or any other suitable mineralor organic acid. The pH of the solution is adjusted suitably. A low pH value results in a rapid dissolution of the mineral material and rapid gel formation, the gelling time being dependent on the pH, a lower pH resulting in a more rapid gelling than a higher pH. Good dissolution for a wide range of mineral materials is obtained at a pH of 0 to 6. The strength of the acid can be, depending on the acid used, from 0.1 to 10 M, typically 0.5 to 5 M.
According to a preferred embodiment, the dissolution of the raw material is preferably carried out at an increased temperature, such as at a temperature of 80 to 100° C., preferably while simultaneously stirring, in order to facilitate the dissolution process. Dissolution takes place within a period from 1-2 hours up to 20 hours depending on the dissolving medium and the solids content of the solution.
Preferably an amount of starting mineral material is dissolved in a solution to provide a metal oxide containing solution which advantageously contains over 1, preferably 5 to 60% by weight of dry matter, which is a suitable concentration for the subsequent use as the binder. After the dissolution is complete, the material nucleates and re-precipitates to form a sol with the desired particle size. (The subsequent stabilization of the sol is brought about by creating in the solution electrostatic repulsion between the particles. The electrostatic repulsion between the sol particles can be effected for example by providing suitable ions in the solution, or by changing the pH.) If necessary, additional water can be added or removed, e.g. by evaporation, if it is necessary, for example for adjusting the viscosity.
(Stabilization may also be achieved by using suitable surfactants and polymers, especially non-ionic ones.) Non-ionic surfactants and polymers can be preferred in some cases as they are not so sensitive to an environment which contains high concentrations of electrolytes and other chemic

Affiliated with

Also associated with

Rating

Method for manufacturing a binder and use thereof does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method for manufacturing a binder and use thereof, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for manufacturing a binder and use thereof will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3057956