CN116324082A

CN116324082A - Coated lightweight fabric, in particular for glider wings

Info

Publication number: CN116324082A
Application number: CN202180065965.7A
Authority: CN
Inventors: 斯蒂芬妮·韦朗
Original assignee: Porcher Industries SA
Current assignee: Porcher Industries SA
Priority date: 2020-10-05
Filing date: 2021-10-04
Publication date: 2023-06-23
Also published as: KR20230084233A; FR3114821A1; WO2022073902A1; FR3114821B1; JP2023544393A; EP4225979A1; TW202223199A

Abstract

The present invention relates to a fabric for a glider, in particular a glider wing, formed of continuous warp and weft yarns and coated on one or both of its surfaces with Polyurethane (PU). The bare fabric has a coverage rate TC of 1.8 to 4, characterized in that: the yarn is made of polyethylene terephthalate (PET); the density of the fabric is between 30 threads/cm and 50 threads/cm (according to the density of warps and wefts); the polyurethane is polyether, polyester or polycarbonate based cross-linked Polyurethane (PU); and the PU is obtained by: (1) Crosslinking (for implementation in an organic solvent phase) of a one-component polyurethane having a modulus at 100% elongation of less than or equal to 5MPa according to standard DIN 53504; (2) A crosslinking agent (based on the proportion of dry crosslinking agent relative to the dry elastomer (between about 5% and about 30% by weight)).

Description

Coated lightweight fabric, in particular for glider wings

[ field of technology ]

The present invention relates to a lightweight fabric for a paraglider type glider (a paraglider type gliding wing) and a fabric production method for producing the same.

[ background Art ]

In the field of gliders, such as paragliders wings, textile manufacturers have long sought to combine light weight, low porosity and durability. This is a difficult balancing problem because reducing porosity is generally equivalent to increasing weight. In fact, the porosity depends on the density of the fabric, namely: depending on the number of warp yarns (warp yarns) and weft yarns (wet yarns) per unit area. The porosity of the fabric also depends on the presence or absence of a coating that serves to more or less close the pores of the fabric. The coating is in fact essential and constitutes a non-negligible part of the coated fabric weight and thus of the glider wing weight. The coating is also important in providing the fabric with suitable stiffness characteristics (stiffness properties) in the cross-diagonal direction (across the bias).

As an essential element necessary to impart the desired porosity, the coating must be durable. Concepts of durability may include various criteria (e.g., uv stability and hydrolytic stability) and thus more generally include atmospheric stability, weathering stability, and water stability. Hydrolytic stability should be considered as a major factor in maintaining the porosity characteristics over time. Currently, gliders such as a glider wing are made of polyamide and use polyester-based or polycarbonate-based Polyurethane (PU) as a coating material. These coatings have relatively good uv resistance, but on the other hand they have limited durability in terms of hydrolytic stability. The weight of the fabric is typically 26g/m ² To 40g/m ² Between them.

The properties of the warp and weft also have an influence on the characteristics and durability of the glider. In practice, the glider is made of polyamide 6.6, but polyamide 6.6 is a hydrophilic polymer (hydrophilic polymer) which imparts a water absorption tendency to the fibres. Thus, paragliders made from polyamide 6.6-based fabrics have a tendency to become heavier and prematurely age under the combined action of ultraviolet light and hydrolysis. The absorbed water reduces the mechanical properties of the polyamide and the coating.

Thus, techniques for producing coated fabrics with sufficient porosity when not in use are known. However, in the practice of paraglider sports, known coated fabrics exhibit degradation of this characteristic in a wet environment, which can cause problems with the service life of the glider wings made therefrom.

[ invention ]

It is an object of the present invention to remedy these drawbacks and to provide a coated fabric which combines the characteristics of light weight and good mechanical properties with the following characteristics: porosity, lower sensitivity to water absorption (or even insensitivity to water absorption), and durability. The coated fabric may have utility for safe and durable gliders, especially paragliders.

It is another object of the present invention to provide such a fabric that retains the optimal mechanical properties necessary for high level paragliders, especially with suitable stiffness in the direction of intersection with the diagonal and higher tear resistance.

Another object is to achieve the following capabilities: the fabric is printed by sublimation printing (sublimation printing) so that a new coated fabric suitable for printing in this way can be provided.

Other objects will become apparent from a reading of the following description of the invention.

These and other objects are achieved by a lightweight fabric formed from continuous warp and weft yarns made of polyethylene terephthalate (PET) and coated with Polyurethane (PU) on one or both of its surfaces, preferably on only one surface. The density of the fabric is preferably 30 to 50 threads/cm in terms of the warp and weft density. The polyurethane is advantageously a polyether, polyester or polycarbonate based cross-linked Polyurethane (PU). According to another preferred feature, the PU is obtained from a one-component polyurethane elastomer. It is generally known that such elastomers are formed from polyol segments (polyethers, polyesters or polycarbonates), isocyanate segments and chain extenders or hydroxylated crosslinkers. An important preferred feature is that the modulus (modulus) of the elastomer at 100% elongation is less than or equal to about 5MPa, in particular between 1MPa and 4MPa, especially between 1MPa and 3MPa, for example about 2MPa, according to standard DIN 53504. Another important preferred feature is that the elastomer (elastomer) is mixed with a crosslinking agent (crosslinking agent) (not to be confused with the crosslinking agent used to form the elastomer). In particular, the proportion of dry crosslinking agent relative to dry elastomer is between about 5% and about 30% by weight, in particular between about 7% and about 20% by weight, in particular between about 8% and about 18% by weight (for example between about 8% and about 16% by weight). The crosslinking agent comprises, in particular, isocyanate, melamine or a mixture of isocyanate and melamine. The crosslinking agent may in particular block all or part of the reactive functional groups (in particular NCO and alcohols) remaining on the elastomer to give additional bonds (bonds) or crosslinks (cross-links) and to give crosslinked PU forming the textile coating. The fabric according to the invention is designed for or suitable for forming a glider wing, in particular a paraglider wing.

The fabric advantageously has a coverage TC of between 1.8 and 4 (in particular between 2.6 and 3.2). TC (coverage) is the coverage of the PET fabric by the braiding operation prior to any possible calendering or the like. The calculation of TC is as follows: TC= (number of filaments/cm. Times.1 diameter of filaments (unit: cm)) _{Warp yarn} ++ (number of filaments/cm. Times.1 diameter of filaments (unit: cm)) _{Weft yarn} . The TC values retained by the present invention correspond to values that provide a sufficiently closed structure for the fabric (possibly subsequently reinforced by a final advantageous calendering process) so that on the one hand the absorption rate of the coating material can be limited to obtain a low porosity suitable for the field of use of the fabric and thus on the other hand the final weight of the coated fabric.

The invention relates in particular to a fabric for a glider, in particular a glider wing, which is formed from continuous warp and weft yarns and is coated on one or both of its surfaces with Polyurethane (PU), the bare fabric having a coverage rate TC of between 1.8 and 4; the method is characterized in that: the yarn is made of polyethylene terephthalate (PET); the density of the fabric is between 30 threads/cm and 50 threads/cm (according to the density of warps and wefts); the polyurethane is polyether, polyester or polycarbonate based cross-linked Polyurethane (PU); and the PU is obtained by: (1) Crosslinking (for implementation in an organic solvent phase (in particular dissolution in a solvent)) of a one-component polyurethane elastomer having a modulus at 100% elongation of less than or equal to 5MPa (in particular between 1MPa and 4MPa, in particular between 1MPa and 3 MPa) according to standard DIN 53504; (2) Crosslinking agent (based on the proportion of dry crosslinking agent relative to dry elastomer (between about 5% and about 30% by weight, in particular between about 7% and about 20% by weight, in particular between about 8% and about 18% by weight)).

The fabric according to the invention is able to maintain its original porosity when not in use or only a slight increase in this porosity occurs during ageing and therefore during use of the fabric. At the same time, these fabrics also have the advantage that their water absorption increases only slightly during aging or use. Thus, it has been found that the formulation can provide a fabric for a glider wing, in particular a glider wing, which has excellent properties in terms of porosity, which is less sensitive to water absorption (or even insensitive to water absorption) during use over time, so that the properties of light weight and good mechanical properties can be continuously maintained, so that the glider wing can be used effectively and safely.

The weight of the fabric (including the coating) may be 25g/m ² To 42g/m ² In particular 27g/m ² To 40g/m ² 。

According to one embodiment, the dry absorption of the coating material is greater than or equal to 10% by weight, in particular between 10% and 30% by weight, preferably between 12% and 30% by weight, more preferably between 15% and 25% by weight. Dry pick-up is the weight ratio of dry coating (especially crosslinked PU) on coated fabric; which represents the weight of the dried/crosslinked coating present on the finished fabric.

PET is composed of repeat units of ethylene terephthalate. However, the scope of the invention extends in practice also to variants comprising small amounts of other units (e.g. less than 10 mole% (especially less than 5 mole%) per polyester molecular chain) of other units (to form these other units, comonomers include for example isophthalic acid, naphthalene dicarboxylic acid, adipic acid, hydroxybenzoic acid, diethylene glycol, propylene glycol, trimellitic acid and pentaerythritol).

The polyester yarn is a multifilament yarn (multifilament yarns). They are formed from a plurality of continuous filaments. According to one embodiment, the fabric comprises warp yarns and weft yarns having a linear density of between 11dtex and 44dtex (for example 11dtex and 33 dtex), in particular a DPF (monofilament linear density) of between 1 and 4 (preferably 1.3 to 3.5).

In one embodiment, the warp and weft yarns have the same count (the same count) and the same DPF.

In another embodiment, the warp and weft yarns have different counts, namely: the yarn count in one direction is strictly higher than the yarn count in the other direction. For example, the yarn count in one direction is between 30dtex and 44dtex (in particular 30dtex and 36 dtex), while the yarn count in the other direction is between 11dtex and 33dtex (in particular 19dtex and 26 dtex), i.e.: the yarn count in the first direction is strictly higher than the yarn count in the other direction. According to one form, the higher count yarn is in the weft direction. According to another form, the higher count yarn is in the warp direction.

In another embodiment, the diversified count (variegated counts) can be provided in the same given direction (warp direction, weft direction, or both). In this case, there are at least two yarns of different count in the warp and/or weft direction.

The tenacity (or tensile strength) of the PET yarns is in particular greater than or equal to 6cN/dtex (in particular between 6cN/dtex and 7 cN/dtex). The elongation at break is in particular greater than or equal to 20% (in particular between 20% and 30%). Toughness and elongation at break (tenacity and elongation at break) were measured according to standard DIN EN ISO 2062.

PET fibers or yarns having these characteristics can be purchased commercially and/or ordered in production.

The polyester yarn optionally comprises one or more additives, such as stabilizers and/or antistatic agents.

In one embodiment, the fabric of the present invention is characterized by a stiffness (stiffness across the bias) in the direction intersecting the diagonal. The diagonal is in the warp direction when measured in a direction at 45 ° to the warp. The diagonal is in the weft direction when measured in a direction at 45 ° to the weft. Elongation was measured as a percentage with a force of 3 pounds (Lbs, i.e., 1.36 kg) applied along the diagonal. The elongation characterizes the stiffness of the fabric in the direction of intersection with the diagonal. The standard used is NF EN ISO 13934-1: samples 50mm wide and 300mm long were prepared. The jaw spacing of the load cell was 200mm and measurements were made at a speed of 100 mm/min.

In particular, the coated fabric according to the present invention has a diagonal elongation in the warp and weft directions of less than or equal to 10% at 3 lbs. Thus, the elongation may be between 1% and 10%, preferably between 3% and 10%, more preferably between 5% and 10%.

According to one embodiment, the measurement is performed according to standard NFG07111 (measuring surface area 100cm ² ) The light fabric has an air permeability of 20L/m or less at a pressure of 2000Pa ² /min。

According to one embodiment, the PET fabric used in the implementation is a calendered fabric (calendered fabric), meaning that it has been calendered before the PU is coated. The calendering process extrudes the fabric and spreads the yarns and constituent filaments, which helps to close the fabric's pores and reduce its porosity.

The fabric of the present invention is obtained by coating with a solvent phase (in solvent phase) polyurethane. The coating may have any of the following features. First, the fabric may be coated on one or both of its surfaces, preferably on one surface.

The polyurethane comprises a rigid part (isocyanate) and a flexible part (polyol). Those skilled in the art know how to find a compromise between the isocyanate/polyol ratio and the nature of the components in order to obtain an elastomer with the desired stiffness, characterized by a modulus at 100% elongation. Preferably, the elastomer employed in the coating is a one-component elastomer, the isocyanate having been reacted with the polyol and the chain extender or cross-linker sequentially to form an elastomer that generally still contains reactive functional groups such as NCO and alcohol. Those skilled in the art can refer to the literature on the production of copolymers or elastomers obtained from isocyanates, polyols and chain extenders or crosslinkers, in particular to Th cases en Materaux PolymIn res et Composites [ Thesis on Polymer Materials and Composites ] by S gol E Hibon, institut National de Sciences Appliqu es-INSA [ National Institute of Applied Sciences ] in Lyon, france,2006.

The coating composition is supplemented with a crosslinking agent, in particular isocyanate or melamine or a mixture of both. The term "isocyanate" is understood to mean isocyanates and polyisocyanates used alone or in combination with one or more other isocyanates and/or polyisocyanates. The term "isocyanate" is understood herein to include the terms "isocyanate" and "polyisocyanate". Polyisocyanates are preferred. As regards melamine, it may in particular be entirely melamine (1, 3, 5-triazine-2, 4, 6-triamine) or a melamine-containing compound or resin (e.g. melamine-formaldehyde resin).

According to one embodiment, the proportion of dry crosslinking agent relative to dry elastomer is between about 5% and about 30% by weight (in particular about 7% and about 20% by weight, in particular about 8% and about 18% by weight).

According to one embodiment, the polyurethane (and the starting elastomer) is polyether-based. In particular, polyether-based polyurethanes are linear or branched and include a polyether polyol portion and an isocyanate portion.

According to one embodiment, the polyurethane (and the starting elastomer) is polyester-based. In particular, polyester-based polyurethanes are linear or branched and include a polyester polyol portion and an isocyanate portion.

According to another embodiment, the polyurethane (and the starting elastomer) is polycarbonate-based. In particular, polycarbonate-based polyurethanes are linear or branched and include a polyol portion of the polycarbonate type and an isocyanate portion.

As regards the elastomer and the crosslinking agent, the isocyanate moieties are preferably aliphatic, in fact aromatic isocyanates have the disadvantage of yellowing over time, so that although they can be employed they are less preferred.

In one embodiment, the lightweight fabric of the present invention is obtained by coating with solvent phase polyurethane. This fabric production process for producing coated fabrics from polyester fabrics is another object of the present invention. The coating may have any of the following features.

The coating step is carried out by techniques commonly employed in textile coating, such as direct coating. The term "direct coating" is understood to mean a direct deposition coating process using, for example, a doctor blade, a cylinder, an air knife or a padding machine and using a meyer rod (or a Champion process).

Another object of the present invention is the use of a PU elastomer or crosslinked PU coating as defined herein in the coating of a high tenacity PET fabric as defined herein. The coating is particularly intended to impart one or more of the properties described herein to the fabric, particularly the elongation along diagonal as described herein; and/or extremely low water absorption when not in use and after aging or use as described herein; and/or there is no or only a slight increase in porosity between the unused coated fabric and the aged or used coated fabric as described herein. Such an application may lead to a production method hereinafter, which is another object of the invention.

The fabric production method for producing a coated fabric comprises in particular the following steps:

(a) Providing a polyester fabric according to the present invention; preferably, the fabric is calendered;

(b) According to the coating rate according to the invention, the solvent-phase polyurethane according to the invention (preferably obtained from a one-component elastomer dissolved in a solvent and mixed with a crosslinking agent, as described herein) is used

Coating one or both surfaces of the fabric;

(c) Heating the fabric until the coating dries and crosslinks;

(d) Obtaining a coated fabric according to the invention;

(e) Optionally, one or both surfaces of the fabric are printed, for example by sublimation printing (sublimation printing).

The object of the invention relates in particular to a fabric production method for producing a coated fabric, wherein:

-providing a fabric made of polyethylene terephthalate (PET) having a density of 30 to 50 threads/cm (expressed in terms of pick-and-place density (warp and weft density));

-coating one or both surfaces of the fabric with a mixture of: a one-component polyurethane elastomer (modulus at 100% elongation of less than or equal to about 5MPa, in particular between 1MPa and 4MPa, in particular between 1MPa and 3 MPa) according to standard DIN 53504; a solvent for the elastomer; and a crosslinking agent (based on the proportion of dry crosslinking agent relative to dry elastomer (between about 5% and about 30% by weight, in particular between about 7% and about 20% by weight, in particular between about 8% and about 18% by weight));

-heating the fabric until the coating dries and crosslinks;

-obtaining a coated fabric;

optionally, one or both surfaces of the fabric are printed, for example by sublimation printing.

The method is intended to produce a fabric as described above, and therefore the characteristics of the elements employed in the production of the fabric are applicable to the method and to the selection of these elements employed in the method, as will not be described in greater detail below.

The PET fabric may advantageously be calendered prior to coating.

According to one embodiment, the PET fabric is calendered between a tool, drum or calender roll and a counter plate prior to coating. The surface of the fabric that the calendering tool passes over (referred to as the "calendering surface") is smooth compared to the other surface.

According to one form, the coating is performed on the calendered surface. The adhesion of the polymer can be enhanced by first pre-applying a primer treatment (primer treatment) on the smooth surface. The treatment may be a physical treatment or a chemical treatment. For example, the treatment is a chemical treatment that provides functional groups that are capable of reacting with groups of the polymer to form chemical bonds.

According to another form, the coating is carried out on another matte surface. It will be appreciated that the coating absorption rate varies depending on the surface concerned, being higher on non-smooth surfaces, which enables the person skilled in the art to adjust the amount and weight of the coating. Two surfaces may also be coated.

According to another embodiment, the PET fabric is calendered between two calendering tools, cylinders or calender rolls prior to coating. Both sides of the fabric were smooth. Subsequently, one or both surfaces are coated, with or without an adhesion treatment as described above.

The PET fabric is preferably calendered at a temperature between 150 ℃ and 250 ℃ (preferably 180 ℃ and 210 ℃). The calendering is preferably carried out at a pressure of between 150kg and 250kg, preferably 180kg to 230 kg. The rotational speed of the calender may be between 1m/min and 30m/min (preferably between 10m/min and 20 m/min).

The lightweight fabric of the present invention is obtained by coating with solvent phase polyurethane. The coating may have any of the following features.

According to standard DIN 53504, the modulus of the PU at 100% elongation is less than or equal to about 5MPa (in particular between 1MPa and 4MPa, in particular between 1MPa and 3 MPa). The PU is dissolved in an organic solvent. The polymer is dissolved in the medium. A cross-linking agent for PU was added to the solution. In particular, the proportion of dry crosslinking agent relative to dry polyurethane is between about 5% and about 30% by weight (in particular about 7% to about 20% by weight, in particular about 8% to about 18% by weight).

The fabric of the present invention is obtained by coating with polyurethane dissolved in a solvent. In particular, the coating contains a one-component elastomer (formed in particular from isocyanate, polyol and chain extender or cross-linker) dissolved in a solvent. During the solvent evaporation, a thin film forms naturally. The solvent is an organic solvent and may be selected from aromatic solvents, alcohols, ketones, esters, dimethylformamide and n-methylpyrrolidone, among others. In a particular embodiment, the solvent is selected from toluene, xylene, isopropanol, butanol, 1-methoxypropan-2-ol, methyl ethyl ketone, acetone, butanone, ethyl acetate, dimethylformamide, n-methylpyrrolidone, and mixtures of at least two of the foregoing. For example, a mixture of toluene and isopropanol.

In one embodiment, the solvent phase polyurethane is characterized by: the concentration of non-crosslinked PU (in particular of one-component elastomers) is between 20% and 50% by weight relative to the PU and solvent mixture. In one embodiment, the solvent-phase polyurethane (in particular the elastomer dissolved in the solvent) is characterized by a viscosity of less than 100000mpa.s at 23 ℃, preferably between 5000mpa.s and 60000mpa.s at 23 ℃ (according to standard DIN EN ISO/A3).

In particular, the drying and crosslinking steps include: drying is first performed, for example, at a temperature between about 90 ℃ and about 120 ℃, and then crosslinking is performed at a temperature between about 140 ℃ and about 210 ℃.

In addition, the fabric coating composition of the present invention may also include additives. The additive may be any additive commonly used in fabric coating compositions. These additives are chosen in particular from viscosity regulators, uv stabilizers, dyes, dispersants and surfactants. According to one embodiment, the coating comprises an anti-uv agent.

In one embodiment, the method comprises: one or more post-treatment steps are performed after the drying and crosslinking steps to impart stain and/or water repellency properties to the fabric. The term "anti-fouling treatment" is understood to mean a treatment with an anti-static and/or anti-sticking product. The term "water repellent treatment" is understood to mean a treatment with a fluorinated resin with or without a cross-linking agent (e.g. isocyanate) for the fluorinated resin. The waterproofing treatment is followed by a drying/crosslinking step. In one embodiment, the post-treatment is performed by any method known to those skilled in the art, in particular by padding, coating, spraying or plasma treatment.

The present invention has the advantage of using a fine yarn comprising a large number of constituent filaments. In addition to lightening the fabric, this makes it possible to significantly reduce the porosity of the fabric before coating, in particular if there is a step of spreading the fibers by calendering before coating, which makes it possible to reduce the absorption of the polymer and thus the relative weight of the coating, and which ultimately makes it possible to reduce the final weight of the fabric, while also ensuring good characteristics in terms of porosity and durability.

It was found that the coated fabric described herein can be printed by the so-called sublimation printing technique. According to one aspect of the invention, the coated fabric is colored, printed or decorated by a sublimation process. The sublimation process may be implemented, inter alia, by printing a pattern on a substrate (transfer substrate (transfer substrate)) with one or more dyes that can sublimate at high temperature. The substrate is then contacted with the coated fabric and then hot calendered, for example, at about 200 c and pressure. The dye gradually becomes gaseous and transfers into the coating and/or onto the surface and/or the fibers. The polyester PET remains stable at this temperature.

The object of the present invention also relates to a lightweight fabric obtained or obtainable by implementing the method according to the present invention.

The object of the invention therefore also relates to an article such as a glider wing, in particular a glider wing, comprising or made of a fabric according to the invention. The article may be provided with a sublimation printed pattern.

The fabrics of the present invention advantageously exhibit high durability, particularly high water stability. This stability can be evaluated by various accelerated aging methods, as described in the examples section:

porosity after hydrolysis and mechanical stress: according to standard NFG07111, it should preferably be kept less than or equal to 20L/m ² /min (especially less than or equal to 12L/m ² Min, especiallyIs less than or equal to 10L/m ² /min); and/or

According to the standard Tappi 441om-90, the water absorption is less than or equal to 1% (in particular less than or equal to 0.9%, for example less than or equal to 0.5%), both in the unused condition and after ageing.

[ detailed description ] of the invention

The invention will now be described by means of examples corresponding to preferred embodiments, which examples are provided by way of illustration, but without any limitation.

Examples:

this example compares the effect of a polyurethane coating on one surface of a conventional polyamide 6.6 fabric coated with PU (Control) and a high tenacity polyethylene terephthalate (PET) fabric coated with PU on one surface according to the present invention.

PA6.6 is a conventional polyamide fabric in the paraglider field, but PU coating is obtained from PU elastomer with modulus of 2MPa at 100% elongation and isocyanate+melamine formaldehyde crosslinker. The proportion of dry crosslinking agent relative to dry elastomer was 8.4%. PU was used in a 50/50 mixture of toluene and isopropanol.

In example 1, PET has a PU coating obtained from a PU elastomer having a modulus of 2MPa at 100% elongation and an isocyanate+melamine formaldehyde crosslinker. The proportion of dry crosslinking agent relative to dry elastomer was 8.4%. PU was used in a 50/50 mixture of toluene and isopropanol.

In example 2, PET has a PU coating obtained from a PU elastomer having a modulus of 2MPa at 100% elongation and an isocyanate+melamine formaldehyde crosslinker. The proportion of dry crosslinking agent relative to dry elastomer was 15.4%. PU was used in a 50/50 mixture of toluene and isopropanol.

In both cases, the PU is an aliphatic polycarbonate-based one-component PU.

The PET had a tenacity of 6.25cN/dtex. The elongation at break (elongation at break) was 24.6%.

The coating is performed by using a doctor blade, followed by a drying step at 100 ℃ and then a crosslinking step at 180 ℃. The speed was 27m/min.

[ Table 1 ]

Methods and measurements employed in the application (features and examples of the invention):

NF EN ISO 2062-measurement of the breaking strength and elongation at break of individual yarns using a constant elongation test apparatus using this standard method A.

Breaking force (unit: one hundredth newton—cn): maximum force to progressively fracture sample in tensile test leading to fracture

Elongation at break (%): increase in sample length measured at sample break

Toughness (cN/tex): the breaking force expressed in cN divided by the linear density of the yarn expressed in dtex (1 tex=1 g/1000m yarn length).

The test allows measuring the force and the elongation at break of the sample, namely: characteristic variables of the yarn.

The yarn was placed between two 500mm apart holding clamps. The device (load cell) then moves the clamps away from each other at a constant displacement speed of 500mm/min and continuously measures the applied force. The force required to break the yarn was measured as the increase in yarn length at break.

The average breaking strength and average elongation at break are two data items that characterize this test. Toughness is calculated from the breaking force divided by the linear density.

The modulus of the one-component polyurethane elastomer at 100% elongation was measured according to DIN 53504. Modulus is defined in 3.4 of the standard "span answer". The measurement was performed on a dumbbell-shaped (Schulterstab) specimen of type S2, but with a bar length I _S 55mm and 200 μm thick. Used in the processThe device is a load cell. Placing dumbbell-shaped test pieces in fixed clamps with a distance of length L ₀ The pretension is as small as possible. The clamps were then moved away from each other at a constant speed of 400 mm/min and the load cell measured the force applied according to the elongation. Modulus or stress at 100% elongation (unit: MPa) is the force ratio measured at 100% elongation at the initial cross section of the test specimen. This is described in section 9.4 "spandex power" of standard DIN 53504.

The porosity and water absorption were evaluated (already evaluated) when not in use and after aging.

The porosity of the fabric after hydrolysis was also measured for aging. To this end, the fabric was placed in a "cotte mine" autoclave containing water at operating temperature and pressure for 4 hours. Subsequently, the fabric was fixed on a milling cutter assembly (i.e., a 4-blade assembly, with the fabric fixed at the end of one of the blades) by floating the fabric outdoors at a high speed for 1 hour of treatment.

The water absorption was measured (already measured) according to the standard Tappi 441om-90 when not in use and after aging. The water absorption is expressed in percent. The device consists of a square rubber substrate and a metal ring, wherein the bottom of the metal ring is covered with a rubber gasket. The sample was placed on a square base and a metal ring was placed on the sample. The system is watertight by means of a clamping device. An amount of water (100 ml) was placed in the metal ring and contacted with the sample for a defined period of time (1 minute). At the end of this period, water was removed from the cylindrical metal ring, and the cylinder described in the standard was used to remove water remaining on the sample surface by moving the cylinder back and forth over the sample placed between the two blotters without applying pressure. The percentage of water absorbed was determined by calculating the weight difference before and after contact with water.

Porosity is measured (already measured) when not in use and after ageing according to the standard NFG07111 or standard ISO 9237, determination of fabric breathability; the result remains the same with the latter criterion being replaced by the former criterion. The sample is mounted on a circular sample holder. Starting the suction to generate a low pressure of 2000Pa, which causes air to flow through the sampleThe product is obtained. Measuring the flow rate of the gas stream in L/m ² /min。

The percent elongation of the fabric was measured (already measured) with a force of 3 pounds (Lbs) applied in the direction intersecting the diagonal line. The elongation characterizes the stiffness of the fabric in the direction of intersection with the diagonal. The standard used is NF EN ISO 13934-1. Samples 50mm wide and 300mm long were prepared. The jaws of the load cell are 200mm away from each other and measurements are made (already made) at a speed of 100 mm/min.

Example 2:

this example compares the effect of PET yarn tenacity.

In the example "control low tenacity PET", the tenacity of PET is 4.3cN/dtex, which is lower than the tenacity of the yarn used in the present invention. The fabric in both cases had a PU coating obtained from a PU elastomer with a modulus of 2MPa at 100% elongation and an isocyanate+melamine formaldehyde cross-linker. For both tests, the proportion of dry crosslinker relative to dry elastomer was 15.4%. PU was used in a 50/50 mixture of toluene and isopropanol, the formulation being the same in both tests.

The control fabric had a cross-grain elongation of less than 5.2% and its porosity after aging was also significantly higher than that of the examples according to the invention. This result is surprising in view of the fact that the coating rate in the control is higher than that of the fabric in the examples according to the invention.

Example 3:

this example shows the effect of the modulus of PU at 100% elongation.

The "control PET" example has a PU coating obtained from a PU elastomer having a modulus of 8MPa at 100% elongation and a melamine formaldehyde crosslinking agent. The proportion of dry crosslinking agent relative to dry elastomer was 15.1%. PU was used in a 50/50 mixture of toluene and isopropanol in the same manner as in the other examples. The textile substrates are identical.

The use of a PU with a modulus of 8MPa at 100% elongation results in a diagonal elongation and a very high post-aging porosity that deviates from the specifications of the present invention.

The water resistance of the fabric of the present invention is remarkable. It has also been found that these fabrics can be printed by sublimation printing. Finally, the fabrics of the present invention have a high level of post-aging porosity stability, which is unexpected.

Claims

1. A fabric for a glider, in particular a glider wing, formed of continuous warp and weft yarns and coated on one or both of its surfaces with Polyurethane (PU), said bare fabric having a coverage TC between 1.8 and 4, preferably between 2.6 and 3.2; according to the formula tc= (number of filaments/cm×diameter of 1 filament (unit: cm)) _{Warp yarn} ++ (number of filaments/cm. Times.1 diameter of filaments (unit: cm)) _{Weft yarn} To calculate TC; the method is characterized in that: the yarn is made of polyethylene terephthalate (PET); PET has a tenacity greater than or equal to 6cN/dtex, in particular between 6cN/dtex and 7 cN/dtex; the density of the fabric is between 30 lines/cm and 50 lines/cm in terms of the warp and weft density; the polyurethane is a polyether, polyester or polycarbonate based cross-linked Polyurethane (PU); and the PU is obtained by: (1) Crosslinking of single-component polyurethanes having a modulus at 100% elongation of less than or equal to 5MPa, in particular between 1MPa and 4MPa, in particular between 1MPa and 3MPa, according to standard DIN 53504, for implementation in an organic solvent phase; (2) A crosslinking agent, in a proportion of between about 5% and about 30% by weight, in particular between about 7% and about 20% by weight, in particular between about 8% and about 18% by weight, based on the dry crosslinking agent relative to the dry elastomer% by weight.

2. The fabric of claim 1, wherein: the elongation at break of the PET yarn is greater than or equal to 20%, in particular between 20% and 30%, according to DIN ENISO 2062.

3. A fabric according to any preceding claim, wherein: the fabric had a coating weight of 25g/m ² To 42g/m ² Between, especially 27g/m ² To 42g/m ² Between them.

4. A fabric according to any preceding claim, wherein: the dry absorption of the coating material is greater than or equal to 10% by weight, in particular between 10% and 30% by weight, preferably between 12% and 30% by weight, more preferably between 15% and 25% by weight.

5. A fabric according to any preceding claim, wherein: the fabric comprises warp yarns and weft yarns having a linear density of between 11dtex and 44dtex, preferably between 11dtex and 33dtex, in particular a DPF monofilament linear density of between 1 and 4, preferably between 1.3 and 3.5.

6. A fabric according to any preceding claim, wherein: the crosslinking agent of the PU is isocyanate, polyisocyanate, melamine, a compound containing melamine or a mixture of isocyanate and melamine.

7. The fabric according to any of the preceding claims, according to standard NFG07111 at 100cm ² The measurement performed on the measured surface area of (2) shows that the pressure of 2000Pa is less than or equal to 20L/m ² Air permeability/min; and/or a water absorption of less than or equal to 1% according to the standard Tappi 441om-90, both in the case of non-use and after ageing.

8. A fabric according to any preceding claim, wherein: the fabric has a diagonal elongation in the warp and weft direction of less than or equal to 10%, in particular between 1% and 10%, preferably between 3% and 10%, more preferably between 5% and 10%, at 3lbs according to standard NF EN ISO 13934-1.

9. A glider, in particular a glider wing, comprising a fabric according to any one of claims 1 to 8.

10. The glider according to claim 9 wherein: the glide wings are provided with sublimation printed patterns.

11. A fabric production process for producing a coated fabric according to any one of claims 1 to 8, wherein:

-providing a fabric made of polyethylene terephthalate (PET) having a density of between 30 and 50 threads/cm in terms of pick-and-place density; the PET yarn has a tenacity, or tensile strength, greater than or equal to 6cN/dtex, especially between 6cN/dtex and 7 cN/dtex;

-coating one or both surfaces of the fabric with a mixture of: a one-component polyurethane elastomer having a modulus at 100% elongation of less than or equal to about 5MPa, in particular between 1MPa and 4MPa, in particular between 1MPa and 3MPa, according to standard DIN 53504; a solvent for the elastomer; and a cross-linking agent in a proportion of between about 5% and about 30% by weight, in particular between about 7% and about 20% by weight, in particular between about 8% and about 18% by weight, based on the dry cross-linking agent relative to the dry elastomer;

-heating the fabric until the coating dries and crosslinks;

-obtaining a coated fabric;

-optionally, printing one or both surfaces of the fabric, for example by sublimation printing.