Classifications

• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C13/00—Fibre or filament compositions
  • C03C13/06—Mineral fibres, e.g. slag wool, mineral wool, rock wool
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C3/00—Glass compositions
  • C03C3/04—Glass compositions containing silica
  • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
  • C03C3/083—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound
  • C03C3/085—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal
  • C03C3/087—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal containing calcium oxide, e.g. common sheet or container glass
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C3/00—Glass compositions
  • C03C3/04—Glass compositions containing silica
  • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
  • C03C3/089—Glass compositions containing silica with 40% to 90% silica, by weight containing boron
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C2213/00—Glass fibres or filaments
  • C03C2213/02—Biodegradable glass fibres

Definitions

• IP tests can be expensive and take several months to perform. It is also un-ethical to un-necessarily use test animals for such purposes.
• in- vitro methods have been tested, which methods can me performed with a reasonable equipment and in a time of only a few days. Such methods are of two categories, biochemical and chemical methods.
• Wardenbach index Wl, which is calculated by the formula (the amounts in % by weight):
• W I BaO + CaO + MgO + Na2 ⁇ + K + B2O3 - 2 * AI2O3.
• the creators of this index believe that fibres having the diameter ⁇ 3 ⁇ m and a length of more than three times the diameter will probable not get free in a standardised IP text if Wl is less than 25, whereas it is the opposite if Wl is greater, or equal to 40. In the interval 25 ⁇ Wl ⁇ 40 certain other estimations have to be used.
• the Wardenbach index seems to be an empirical construction which points to a glass having a certain instability which could cause the actually sought high solubility, that is a short lifetime for the fibres of the organism.
• the solubility is not, however, the only determining property of a fibre.
• fibres may be attacked by the contacting liquid in at least four various ways.
• a first way is by a homogenous solution, that is when ions from the glass of the fibres enter a solution by the same speed over the entire fibre surface without any noticeable change of the remaining glass.
• the second way is a selective dissolving, whereby certain ions enter a solution more easily than other ions. This means that the remaining glass is impoverished of said dissolved ions.
• Both said ways make the diameter of the fibres become reduced by time but basically evenly over the entire length of the fibre.
• a third way is to transfer the glass of the fibre to a gel down to a certain depth.
• the layer of gel is thereafter broken off and a new layer of gel is formed. Also this method leads to a basically even reduction of the diameter of the entire length of the fibre.
• the fourth way is to form cavities or scars at the surface layer of the fibre.
• the cavities can be relatively deep and said cavities may possibly be a part of the reason that the fibres are broken up into short pieces of the tissues. Said phenomena has often been noted in animal tests.
• the shortening of the fibres makes it easy to move off the fibres. It is considered that fibres below a certain minimum length, which by various sources is mentioned as 5-20 ⁇ m, are not cancerogene.
• the observations can only in part be quantified, and the observations and the interpretations thereof are to a great extent subjective. Depending thereon it is not very easy to reproduce same.
• the present invention is partly built on studies of fibres manufactured in model scale, wherein several kilos of a mineral batch is melted in an electrode furnace, whereupon the melted mineral is fibrillated by a so called cascade spinning machine in which the melted mineral is supplied to the envelope surface of a rapidly rotating steel cylinder, a spinning wheel, which is cooled at the inner thereof, and from there the melted mineral is in part thrown out as fibres and is in part thrown onto the succeeding spinner wheel etc.
• a technical glass as will be found in mineral wool fibres, contains several main oxides which co-operate with each other in a complicated manner.
• the principle roll of some of said oxides is, indeed, known for certain composition areas but the details are mainly unknown as concerns the in the complex interaction.
• the oxides Si, Al and Na it is possible to find an area in a three dimensional co-ordinate system represented by a volume, in which stable glass can be manufactured. It is possible to thereafter indentify various part volumes, regions, which have different properties. Stepwise transitions do not exist, but the regions have to be defined by means of one property, for instance the solubility measured by a particular method.
• each region there should be at least one point, which, considering the studied property, represents an extreme value, either a maximum or a minimum value. Since such extreme curves many times have relatively level characteristics it can be difficult to define the exact extreme point.
• the invention relates to compositions which both act as desired in a bio-environment and are suitable for rational production of mineral wool having good properties for the product to be useful.
• composition areas have been identified as highly valuable.
• the following table contains amounts in % by weight in three stages A, B and C. The table is to be understood so that, for a certain oxide, irrespective what values exist for the other oxides, the A-area is a minimum demand, the B-value is a better choice and the C-value is the best choice. If an amount of an oxide changes from having existed outside the B-area to be present inside the B-area a noticeable improvement is obtained even if all the other oxides is present outside the B-area.
• the meaning of the table thus is that, if for instance the content of AI2O3 is lowered from 5 to 3 by weight, there is obtained a noticeable improvement in the total evaluation of the usefulness of the glass.
• the content of B2O3 can preferably be rather low since an effect is obtained already at small amounts thereof. It is considered that at least 0.3 % by weight is needed.
• the values of the table are in % by weight.
• the sum of ferric oxides is expressed as FeO, the sum of alkalic earth as CaO and the sum of alkalic oxides as Na2 ⁇ .
• compositions of the described type there can also exist minor amounts of other oxides like oxides of Mn and Ti. Experiences show that amounts of 0.5 - 2 % by weight are suitable.
• An addition of phosphorus has a favourable effect if added in an amount of between 1 and 4 % by weight.
• the invention explicitly includes such compositions.
• composition according to the invention lies, as concerns the content of Si ⁇ 2, within the area in which there is traditionally found rockwool.
• Rockwool having an addition of boron is described in the Danish patent application No 8301226. Adding boron to a rockwool glass does not al all, however, lead to a useful glass, it is necessary to, concurrently therewith, reduce the amount of AI 2 O 3 .
• Glass compositions according to the invention are particularly adapted for melting in cupola furnaces or in electrode furnaces and a subsequent fibrillation by means of a cascade spinning machine.

Applications Claiming Priority (3)

Publications (1)

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• 1994
  • 1994-07-07 SE SE9402405A patent/SE504288C2/sv not_active IP Right Cessation
• 1995
  • 1995-06-13 EP EP95925192A patent/EP0768989A1/en not_active Withdrawn
  • 1995-06-13 SK SK10-97A patent/SK1097A3/sk unknown
  • 1995-06-13 AU AU29398/95A patent/AU2939895A/en not_active Abandoned
  • 1995-06-13 PL PL95318055A patent/PL318055A1/xx unknown
  • 1995-06-13 EE EE9700220A patent/EE03481B1/xx not_active IP Right Cessation
  • 1995-06-13 CZ CZ19978A patent/CZ288777B6/cs not_active IP Right Cessation
  • 1995-06-13 HU HU9700020A patent/HU217180B/hu not_active IP Right Cessation
  • 1995-06-13 WO PCT/SE1995/000714 patent/WO1996001793A1/en not_active Application Discontinuation
• 1996
  • 1996-12-11 NO NO965293A patent/NO965293D0/no not_active Application Discontinuation
• 1997
  • 1997-01-03 FI FI970016A patent/FI970016A/fi unknown

Non-Patent Citations (1)

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