Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Reexamination Certificate
2000-09-12
2003-02-04
Kelly, Cynthia H. (Department: 1774)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
C428S375000, C428S378000, C428S391000, C065S381000, C065S382000, C065S384000, C427S385500, C427S389700, C427S178000, C264S211120
Reexamination Certificate
active
06514612
ABSTRACT:
In the field of reinforcing yarns and composites, the present invention relates to glass yarns coated with a novel sizing composition, as well as to the composition in question, to the process for producing the yarns using this composition and to the composites made from the yarns.
Reinforcing glass yarns are manufactured, in a known manner, from molten glass threads flowing through die orifices. These threads are drawn in the form of continuous filaments and these filaments are then assembled into base yarns, which are then collected.
Before being assembled in the form of yarns, the filaments are coated with a sizing composition by passing them through a sizing member. This deposition is necessary in order to obtain the yarns and allows these yarns to be used effectively in the production of composites. Sizing has the following usual functions: it protects the yarns from abrasion and thus prevents them from breaking during their manufacture and, possibly, during their use; it furthermore allows the combination of yarns with organic and/or inorganic materials to be reinforced, by facilitating, in particular, the wetting and/or impregnation of the yarns by these materials. In most cases, sizing also enhances the adhesion between the glass and the material to be reinforced and allows composites to be obtained which have improved mechanical properties.
Sizing can also ensure the integrity of the yarns, i.e. the linking together of the filaments within the yarns. This integrity is especially desired in textile applications in which the yarns are subjected to high mechanical stresses. The reason for this is that, if the filaments are not very solidly attached to each other, they break more easily and disrupt the functioning of the textile machines. Non-integrated yarns are moreover considered as being difficult to handle.
Sizing compositions are chosen so as to fulfil the functions mentioned above and so as to resist the shear induced by the passage of the filaments at the drawing speeds (several tens of metres per second) and so as to wet the surface of the filaments at the said speeds. As a general rule, they are also chosen so as not to undergo chemical reactions giving rise to a large increase in viscosity at room temperature (during their storage) and at the die (polymerization of the sizing, for example, making it impossible to be deposited).
Most of the sizings commonly used are aqueous sizings which are simple to handle, but which need to be deposited in large amounts on the filaments in order to be effective. Water generally represents 90% by weight of these sizings (in particular for reasons of viscosity), thereby making it necessary to dry the yarns before they are used for reinforcing, since the water can be detrimental to the correct adhesion between the yarns and the materials to be reinforced. These drying operations are long and expensive, they need to be adapted to the conditions for manufacturing the yarns and they are not always of optimal efficacy. They can also entail risks of irregular and/or selective migration of the sizing components when they are carried out on packages and/or phenomena of coloration or deformation of the packages. This deformation is also observed, in the absence of drying, on the straight-edged packages (rovings) of fine yarns (i.e. yarns with a “yarn count” or “linear mass” of 300-600 tex (g/km) or less) coated with aqueous sizings.
Certain patents describe compositions which require no drying operations, such as anhydrous compositions. However, the number of these compositions which are suitable for coating glass yarns remains low in comparison with the number of existing aqueous compositions, and the choice among these compositions as a function of the desired application thus remains limited. In particular, among the compositions requiring no drying operations, there is at the current time no composition which allows the desired threads to be obtained in applications such as the manufacture of fascia (facade) reinforcement grilles, fabrics for vehicles, or hollow bodies by winding (i.e. by deposition, onto a rotating mould, of reinforcing yarns impregnated with resin), since these yarns need to have a better aptitude for impregnation than the reinforcing yarns most commonly used in other applications.
The present invention relates to a novel sizing composition which is suitable for advantageously coating glass yarns and which does not require drying of the yarns after it has been deposited, this composition giving yarns which are particularly suitable for impregnation with reinforcing materials, but nevertheless having enough integrity to be able to be handled, this composition thus making it possible to widen the field of sizings and to open the way to novel products and to novel applications.
The subject of the present invention is also novel sized glass yarns with the properties defined in the above paragraph, the said yarns being suitable for effectively reinforcing organic and/or inorganic materials for the production of composites, and, in particular, being particularly suitable for the manufacture of fascia reinforcement grilles, hollow bodies by winding and fabrics for vehicles.
The sizing composition according to the invention consists of a solution whose solvent content is less than 5% by weight, this solution comprising at least 60% by weight of polymerizable components, at least 60% by weight of these polymerizable components being components with a molecular mass of less than 750 and these polymerizable components comprising at least one mixture capable of polymerizing:
of component(s) containing at least one reactive acrylic function and/or at least one reactive methacrylic function, and
of component(s) containing at least one reactive primary amine function and/or at least one reactive secondary amine function, at least 20% of the polymerizable components containing at least two reactive functions chosen from acrylic, methacrylic, primary amine and secondary amine functions.
Hereinbelow, the terms “(meth)acrylic component” and “primary and/or secondary amine component” are intended to refer, respectively, to a “component containing at least one reactive acrylic function and/or at least one reactive methacrylic function” and a “component containing at least one reactive primary amine function and/or at least one reactive secondary amine function”. Similarly, the term “reactive function” is intended to refer to a function capable of participating in the polymerization reaction of the mixture and the terms “polymerization” and “polymerize” are intended to refer, respectively, to “polymerization and/or crosslinking” and “polymerize and/or crosslink”, it being possible for the polymerization to take place at room temperature or under heat. Lastly, according to the invention, the term “composition comprising . . . ” is intended to refer to a composition in which the initial constituents are . . . ” or alternatively “composition formed of . . . ”.
In the composition according to the invention, the optional solvent(s) is(are) essentially one (or more) organic solvent(s) required for the dissolution of certain polymerizable compounds. The presence of solvents in limited amount does not require specific treatments to remove them; in most cases, the sizings according to the invention are, in addition, totally free of solvents, i.e. of compounds acting solely as solvent in the solution.
The polymerizable components, these components being essential for the sizing and forming part of the structure of the polymerized sizing, represent between 60 and 100% by weight of the sizing composition according to the invention, mainly between 70 and 99.5% by weight of the composition, and in most cases between 75 and 90% by weight of the composition. These polymerizable components are more conveniently referred to collectively hereinafter as the “base system”.
Preferably, the base system consists mainly (i.e. to more than 50%, preferably to at least 75% by weight and up to 100% by weight in most cases) of (meth)acrylic component(s) and of pri
Moireau Patrick
Roubin Marc
Gray J. M.
Kelly Cynthia H.
Vetrotex France
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