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

Definitions

• the invention relates to reinforcing glass yarns and composites based on organic and / or inorganic materials incorporating said glass yarns.
• the field of reinforcing glass wires is a very particular area of the glass industry.
• the reinforcing glass threads are obtained by the process of mechanically stretching molten glass threads flowing from orifices arranged at the base of a die generally heated by Joule effect, and to gather said filaments to form the thread of glass.
• the yarns are made from specific glass compositions which must make it possible to obtain filaments of a few micrometers in diameter and the formation of continuous yarns capable of performing the reinforcing function in organic and / or inorganic materials which is devolved to them, this in order to give them better mechanical properties.
• the reinforcing glass threads are used as such or in the form of organized assemblies such as fabrics.
• the mechanical properties of these reinforced materials are mainly governed by the composition of the glass which constitutes the reinforcing threads.
• the most known glasses for this purpose are the "E" type glasses of composition SiO 2 -Al 2 ⁇ 3-CaO, the archetype of which is described in patents US-A-2,334,981 and 2,571,074 and which have a composition essentially based on silica, alumina, lime and boric anhydride.
• This latter component present at a content ranging from 5 to 13%, is added in replacement of the silica, and it makes it possible to fiberize the glass E under very advantageous conditions, in particular with a working temperature (temperature at which the glass has a viscosity equal to 1000 poise) relatively low, of the order of 1200 0 C, a liquidus temperature lower by about 120 0 C at the working temperature and a low devitrification speed.
• a working temperature temperature at which the glass has a viscosity equal to 1000 poise
• composition of glass E defined in ASTM D 578-00 is as follows (in weight percent): 52 to 56% SiO 2 ; 12 to 16% AI 2 O 3 ; 16 25% CaO; 5 to 10% B 2 O 3 ; 0 to 5% MgO; 0 to 2% Na 2 O + K 2 O; 0 to 0.8% TiO 2 ; 0.05 to 0.4% Fe 2 O 3 ; 0 to 1% of F 2 .
• Boric anhydride B 2 O 3 acts as a flux in the mixture of vitrifiable raw materials, which, as already mentioned, makes it possible to perform glass fiberizing in better conditions. conditions.
• these constituents have the disadvantage of being volatile and generating boron and fluorine emissions which must necessarily be treated in pollution control facilities before their release into the atmosphere. The implementation of this treatment generates a significant additional cost in the son of glass.
• the raw materials from which these constituents are obtained, in particular B 2 O 3 which must represent at least 5% by weight of the glass are relatively expensive.
• ASTM D 578-00 provides for other glass reinforcing wires E that may not contain boron.
• These yarns which are more particularly intended for producing fabrics for electronics, have the following composition (in percentage by weight): 52 to 62% of SiO 2 ; 12 to 16% AI 2 O 3 ; 16 to 25% CaO; 0 to 10% B 2 O 3 ; 0 to 5% MgO; 0 to 2% Na 2 O + K 2 O; 0 to 1.5% TiO 2 ; 0.05 to 0.8% Fe 2 O 3 ; 0 to 1% F 2 .
• the object of the present invention is to provide reinforcing threads made of a glass having a composition different from that of glass E, and which have a satisfactory level of mechanical performance, in particular in terms of tensile strength, and a favorable cost. .
• the present invention is more particularly interested in "fine" glass son, that is to say having a linear density less than or equal to 300 tex.
• This object is achieved according to the invention by virtue of the lower alumina glass fibers, the composition of which comprises the following constituents within the limits defined below, expressed in percentages by weight:
• Silica SiO 2 is one of the oxides which forms the network of glasses according to the invention and plays an essential role for their stability.
• the silica content is less than 62%, the glass obtained is not sufficiently viscous and devitrifies too easily during fiber drawing. Beyond 72%, the glass becomes very viscous and difficult to melt.
• the silica content is between 64 and 70.5%.
• Alumina Al 2 O 3 is also a formator of the glass network according to the invention and plays an essential role with respect to stability.
• the alumina content is limited to 10% essentially for reasons of devitrification and reduction of the final cost of the glass.
• An alumina content of less than 2% results in a significant increase in the hydrolytic attack of the glass.
• the alumina content is greater than or equal to 3% and advantageously greater than or equal to 3.5%.
• the sum of the silica and alumina contents is greater than 70.5% in order to obtain a satisfactory level of hydrolytic resistance.
• the sum of the silica and alumina contents is less than or equal to 75% so as not to increase the melting temperature of the vitrifiable raw materials too much.
• the CaO content makes it possible to adjust the viscosity and control the devitrification of the glasses.
• a CaO content greater than 20% increases the devitrification rate of Ca.sub.SiO.sub.3 (wollastonite) detrimental to good fiberization.
• a content of less than 7% decreases the hydrolytic resistance of the glass unacceptably.
• the CaO content is greater than or equal to 8%, and advantageously less than 12%.
• Magnesia MgO allows, in connection with CaO, to reduce the liquidus temperature of the glass.
• the addition of MgO in the indicated content makes it possible to introduce competition between the growth of wollastonite crystals and the growth of diopside crystals (CaO 2 MgO 2 SiO 2), which has the effect of slowing down the growth of these two types. crystals and in the end to give the glass a better resistance to devitrification.
• MgO contributes to obtaining a high hydrolytic resistance.
• the MgO content ranges from 1 to 7%, preferably from 3.5 to 6.5%.
• the alkaline oxides Na 2 O, K 2 O and Li 2 O, may be introduced into the composition according to the invention to help limit devitrification and reduce the viscosity of the glass.
• the content of alkaline oxides must however remain less than or equal to 14.5% in order not to degrade the hydrolytic resistance of the glass and maintain the mechanical properties of the wire at an acceptable level.
• the content of alkaline oxides is preferably less than 14%, advantageously greater than 10.5%, more preferably greater than 11% and even more preferably greater than 11.5%.
• the Li 2 O content is generally less than 1%, advantageously less than or equal to 0.5%, especially zero, essentially for reasons of cost.
• the addition of Li 2 O in the glass composition is advantageous for the production of son consisting of small diameter filaments because it limits the deposition of the glass at the openings at the base of the die ("sending") which disturbs the fiberization.
• BaO, SrO and ZnO may be present in the glass composition in a total content of less than 4%, preferably less than 2% in order not to increase the cost.
• the composition is free of BaO, SrO and ZnO.
• B2O3 boron oxide acts as a fluidizer. Its content in the glass composition according to the invention is limited to 4%, preferably less than or equal to 2%, to avoid the problems of volatilization and pollutant emission, and not to significantly increase the cost of the composition.
• Boron may be incorporated as raw material in the form of waste glass son containing boron, in particular E glass. In general, the compositions according to the invention are free of B2O3.
• Fluorine can be added in small quantities to improve the melting of the glass, or be present in the impurity state from the vitrifiable raw materials, without however exceeding 2%.
• the fluorine content is less than 1% because beyond this can occur risks of pollutant emissions and corrosion of refractory furnace.
• the compositions according to the invention are free of fluorine.
• the glass composition may further comprise AS2O3 arsenic oxide in an amount not exceeding 0.15% to improve the refining of the glass.
• Arsenic oxide is used in addition to conventional refining agents such as sulphates alone or in combination with coke.
• the content of AS2O3 is less than or equal to 0.13% and advantageously less than or equal to 0.07% so as to prevent the risks of polluting emissions.
• the compositions according to the invention do not contain As2O3.
• the glass yarns according to the invention are obtained from the glasses of composition previously described according to the following method: a plurality of threads of molten glass, flowing from a multiplicity of orifices arranged at the base of a or several dies, in the form of one or more plies of continuous son, and then the filaments are gathered in one or more son that is collected on a moving support.
• the filaments are generally coated with a sizing composition designed to protect them from abrasion and facilitating their subsequent association with the materials to be reinforced.
• the moving support may be a support in rotation when the son are collected in the form of windings, or a support in translation when the son are cut by a member also serving to stretch or projected by a member for stretching to form a mat.
• These yarns can undergo transformation operations, for example to "voluminize", to give them a twist or to assemble them to form son of even higher linear density.
• the son can thus be in different forms: continuous or cut son, grids, fabrics, knits, braids, ribbons or mats.
• the yarns are assembled into structures in the form of grids, fabrics and mats.
• These yarns intended to be used in textile applications advantageously have a filament diameter less than or equal to 11 micrometers, preferably less than or equal to 9 micrometers. They are usually twisted and / or wired and coated with a specific size to resist weaving operations.
• the son of greater diameter and linear density are more particularly intended for the reinforcement of plastics.
• Their linear density may vary to a greater extent and the diameter of the filaments constituting them may be up to 30 ⁇ m.
• the molten glass feeding the dies is obtained from pure raw materials (for example from the chemical industry) or more generally from natural materials (the latter sometimes containing trace impurities), these raw materials being mixed. in appropriate proportions to obtain the desired composition, and then being melted.
• the temperature of the molten glass (and therefore its viscosity) is adjusted in a traditional way so as to allow the fiberizing avoiding the problems of devitrification.
• the "forming range”, denoted ⁇ T, is one of the evaluation criteria for fiber drawing. It corresponds to the difference between the forming temperature of the yarns (noted and the liquidus temperature (denoted T
• working temperature is meant the temperature at which the glass has a viscosity equal to 1000 poises (denoted by T
• liquidus temperature (denoted by T
• the liquidus temperature gives the lower temperature limit at which it is possible to fiberize the glass.
• the glass strands in accordance with the invention can be fibers under particularly advantageous conditions because the forming range is high, at least 70 ° C., preferably at least 80 ° C., and up to at 135 ° C.
• 0g 3 is relatively low, at most equal to 1240 0 C, which has the advantage of not having to heat the glass too much and minimize the wear of the die.
• the forming temperature is at most 1230 ° C and more preferably at most 1220 ° C.
• the glass yarns according to the invention may be associated with filaments of organic material, either during drawing to form composite yarns, or after forming the glass yarn in a subsequent step to form mixed yarns.
• the glass son according to the invention are intended in particular to be used as reinforcing elements of composite parts based on organic (s) and / or inorganic (s) material (s).
• the glass threads according to the invention can represent only part of the glass threads or all of these threads.
• compositions shown in Table 1 are produced.
• the compositions of Examples 1 to 3 correspond to glasses having been melted, and the compositions of Examples 4 to 10 are obtained by calculation using a model established by the applicant.
• Glass threads (filament diameter: 9 ⁇ m and linear density: 68 and 34 tex, filament diameter: 7 ⁇ m and linear density: 22 tex) are obtained in a conventional fiberization plant from the glasses of examples 1, 2 and 3, and conventional glasses E with boron (Reference 1) and without boron (Reference 2).
• the glass filaments are coated with a composition traditional sizing before their gathering in wire.
• the amount of sizing deposited is of the order of 0.7 to 1.1% of the weight of the final wire.
• Table 1 are reported:
• the fiber-drawing range of the glasses according to the invention is greater than that of boron-free glass E (reference 2), and close to that of glass E with boron (reference 1) for examples 7 and 9, or even greater for the example 8.
• the working temperature and the liquidus temperature of Examples 1 to 10 are compatible with the usual conditions for fiberizing glasses E.
• the unit tensile strength of the yarn of Examples 1 to 3, before twisting, is sufficiently high to allow the yarn to be used in textile weaving operations.

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• Glass Compositions (AREA)

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• 2007
  • 2007-10-31 FR FR0758731A patent/FR2922885B1/fr not_active Expired - Fee Related
• 2008
  • 2008-10-30 EP EP08845842A patent/EP2215027A2/de not_active Withdrawn
  • 2008-10-30 MX MX2010004443A patent/MX2010004443A/es active IP Right Grant
  • 2008-10-30 US US12/739,871 patent/US8367571B2/en not_active Expired - Fee Related
  • 2008-10-30 WO PCT/FR2008/051953 patent/WO2009056768A2/fr active Application Filing
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