Classifications

• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H3/00—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length
  • D04H3/002—Inorganic yarns or filaments
  • D04H3/004—Glass yarns or filaments
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H3/00—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length
  • D04H3/02—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length characterised by the method of forming fleeces or layers, e.g. reorientation of yarns or filaments

Definitions

• the present invention relates to anisotropic mats of continuous glass strands and to methods and devices for obtaining such mats.
• the “mats” of continuous glass strands are “mattresses” or “felts” or “sheets” of continuous glass strands distributed in regular layers and most often maintained by a binder, and are used for the reinforcement of organic matter.
• the most common mats have identical properties in all directions, the wires being placed within the mast without preferential orientation.
• anisotropic mats having a preferential direction of orientation of the wires, this direction corresponding for example to the direction of travel of the conveyor on which the mats are formed (we then speak of wires oriented “longitudinally” or of preferential longitudinal direction) or in a direction transverse thereto (we then speak of wires oriented “transversely” or of preferential transverse direction).
• Current methods and devices do not, however, allow anisotropic mats to be produced in a cost-effective manner (in particular mats with preferential transverse orientation) and the mats obtained so far have limited rate of fibers oriented transversely or longitudinally.
• the object of the present invention is to provide anisotropic mats, in particular mats with preferential transverse orientation, having improved properties compared to existing ones as well as efficient methods and devices making it possible to obtain such mats.
• these mats comprising at least one layer of continuous glass strands comprising at least 60%, preferably at least 65% and, in a particularly preferred manner, at least 70% by weight of wires arranged in a preferred direction (or directing or generating), this direction being preferably transverse or possibly being, in certain cases, longitudinal.
• wires deposited in a preferred direction is meant wires which deviate on average by less than 20 ° (preferably less than 15 ° and advantageously less than 10 °) from said direction or which are oriented in a direction deviating by less than 20 ° from this preferred direction.
• glass strands is understood according to the invention son comprising glass filaments. It can thus be traditional glass yarns composed of glass filaments or composite yarns composed of organic filaments and glass filaments.
• the mats according to the invention preferably have several layers of intermingled continuous glass strands, at least one of these layers comprising at least 60% of strands oriented along a direction in accordance with the present invention (preferably, a transverse direction).
• the mat comprises at least one layer and preferably several layers of glass strands comprising transversely oriented strands and comprises at least one layer of glass strands comprising oriented strands longitudinally preferably placed between two other layers, so as to form a structure resembling a grid.
• Such a mat (or a composite produced from such a mat) has good mechanical properties in the two preferred directions of the mat for a reduced glass content compared to a mat (respectively a composite produced from a mat ) isotropic with equivalent properties in all directions.
• This mat (or composite) according to the invention also has improved properties in its non-preferred directions compared to a grid of glass strands obtained by textile processes (respectively to a composite obtained from this grid).
• the mat according to the invention may comprise one or more layers of yarns arranged without preferential orientation or comprising less than 60% by weight of yarns having a preferential orientation.
• the majority (if not all) of the layers of the mat comprise (each) at least 60% by weight of wires oriented in a preferred direction, the mat then having one or more preferred directions of orientation of the wires.
• the mat as a whole, comprises more than 60% and, preferably at least 65% by weight of threads oriented in a preferred direction (for example transverse or longitudinal) or of threads oriented in two distinct preferential directions (for example a transverse direction for part of these wires and a longitudinal direction for another part so as to form a grid as explained above).
• the mats according to the invention also advantageously comprise less than 90% and preferably less than 85% or even less than 80% by weight of wires arranged in the same preferential direction in order to maintain sufficient mechanical properties in the other directions.
• One or more layers with preferential orientation may however comprise up to 100% of threads oriented along a direction (in particular the layers oriented longitudinally).
• the layer or layers with preferential transverse orientation comprise less than 95% by weight of wires oriented transversely, these wires further having undulations and / or loops.
• the layers with preferential longitudinal orientation comprise 100% by weight of longitudinally oriented wires, these wires also being rectilinear and parallel.
• the mats according to the invention comprising at least one layer of wires having a preferential transverse orientation are characterized at the level of this layer by a rate of loops of between 1 and 2, particularly preferably between 1 and 1.5 Le rate of loops corresponds to the speed of drawing of the wires projected onto the conveyor in order to form the mast divided by the speed of beat of the projection member (measured at the level of the conveyor), expressed in the same unit, in the process for making these mats according to the invention (explained below).
• the wires oriented in a preferential transverse direction within the mat generally undulate on either side of this preferential direction and / or form loops, the local spacing of the wire relative to the preferential direction not exceeding 1 0 cm and preferably 8 cm (curls) or 4 cm (undulations).
• the anisotropic mats according to the invention have several advantages; they very easily permeate organic materials to be reinforced and are particularly suitable for molding; they have particularly high mechanical strength properties in the preferential direction (s) of the glass strands; they can advantageously have very low grammages, unlike traditional mats, in particular grammages between 80 and 450 g / m approximately and, in particular, between 1 00 and 300 g / m 2
• the use of glass mats according to the invention makes it possible to produce composite products having particularly high mechanical properties in at least one direction for a lower glass content (in particular up to 2 times lower) than that present in the composites produced from existing mats. Lowering the glass content in composite products for a identical reinforcement provides more economical and lighter products.
• At least one of the mechanical properties (tensile stress, flexural stress, Izod or Charpy shock) of the mats according to the invention having a single preferential direction of orientation of the wires (unidirectional mats), or of the layer or layers of the masts according to the invention comprising at least 60% by weight of wires arranged in a preferred direction is, when measured in the direction of orientation of the wires, at least 1, 4-1, 5 times greater (and preferably 4 times, or even 10 times greater) than that measured in the direction perpendicular to this preferred direction.
• At least one mechanical property of these composites is, when measured in the direction of orientation of the wires, at least 1.5 times greater than that measured in the direction perpendicular to this preferred direction.
• the present invention also relates to a method for making mats according to the invention having a preferential transverse direction, this method comprising the following steps: for each layer of the mat, one or more wires are mechanically driven by a drawing system (“ stretching wheel ”) and / or drive in rotation about a fixed axis and provided with a projection member (“ internal wheel ”,“ fin wheel ”) driven by a flapping movement relative to this axis, the wire or wires being projected and distributed by said member on a conveyor moving transversely relative to the direction of the projected son, the flapping movement of at least one projection member being provided by means of a servo motor.
• a drawing system stretching wheel
• a projection member internal wheel ”,“ fin wheel ”
• this process is a direct process, the thread or threads of each layer of the mat being obtained from at least one die by drawing a multiplicity of melted glass fillets, flowing from a multiplicity of orifices arranged at the base of the die in the form of one or more plies of continuous filaments, then by gathering the filaments in the form of the yarns, the drawing and training of the yarns being carried out by means of the drawing system mentioned in the definition of the invention.
• thermoplastic organic material it is also possible to extrude and entrain a thermoplastic organic material at the same time as stretching glass filaments in the form of filaments, the paths followed by the glass filaments and the converging thermoplastic filaments towards each other before said filaments are combined into one or more composite threads which are driven by the drawing system mentioned in the definition of the invention.
• This embodiment of the invention makes it possible to obtain a mat having at least one layer of composite wires.
• the process according to the invention (in particular the direct process) has improved productivity compared to the processes for manufacturing existing mats and is particularly suitable for producing the mats according to the invention.
• the method according to the invention uses a servomotor for the projection of wire from a drawing system whose axis is fixed.
• the use of a servomotor makes it possible to increase the speed of beat of the projection member, this speed being able to reach more than 1 00 beats per minute, and in particular 1 60 beats per minute (against a few tens of beats at the minute for traditional mechanical means).
• the increase in the number of beats makes it possible to produce mats with a strong orientation according to the invention and allows the use of wider conveyors.
• the conveyor thus has a width of approximately 3 m.
• the servomotor of the process according to the invention is an electric, hydraulic or pneumatic motor making it possible to vary the beat speed of the projection member (or the speed of the axis of this member with respect to the axis of the system d 'stretching or training) depending on the projection angle of the wire (s).
• the speed of movement of the projection member can vary depending on the position of this member and therefore on the projection angle of the wires. measured for example with respect to a vertical axis.
• the booster used according to the invention is a "bruchless" motor.
• the position of the projection member can be continuously monitored and the amplitude and shape of the beats can be precisely adjusted, the speed or shape changes occurring quickly and which can be controlled by electronic control, by means of a computer for example.
• electronic control by means of a computer for example.
• Such control and such speed are not encountered in the usual methods of manufacturing masts using complex mechanical means (assemblies of cams and complex connecting rods) exhibiting high inertia.
• the number of beats per minute of the projection member and the speed of the conveyor are chosen relative to each other so as to obtain a pitch less than 1.5 times the effective width. for depositing the wire or wires and preferably less than the effective width for depositing the wire or wires.
• the pitch corresponds to the distance traveled by the conveyor on which the mat is formed during a round trip of the projection member.
• the width of deposit of the wire (s) is generally between the width of the drawing wheel and twice this width.
• the number of beats of the projection member per minute is at least 5 times greater in value than the speed of the conveyor (expressed in meters per minute).
• the average speed of beat of the projection member (or the average speed of deposition of the wire or wires on the conveyor ) at the conveyor (speed generally of the order of 8 to 15 m. s " ) and the wire drawing speed (generally of the order of 1 5 to 24 m. s 1 ) are chosen one with respect to the other so that the ratio of this last speed to this first speed is between 1 and 2.
• each layer of the mat produced is generally obtained from a die, each die being associated with a stretching system provided with a projection member and each projection member being moved by a its own engine.
• the flapping movement of at least one projection member is ensured by means of a servomotor, this making it possible to produce at least one layer of continuous glass strands comprising at least 60% by weight of wires oriented transversely within the mast.
• several (preferably all) of the projection members are provided with servomotors, each servomotor controlling a projection member.
• the projection members being advantageously moved independently of each other in the method according to the invention, it is thus possible to produce layers of different characteristics, the projection members (as well as the stretching systems which are respectively associated with them) which can be adjusted independently of each other and which can in particular operate with different beat rates.
• At least one layer of the mat is also formed by depositing on the conveyor or on one or more layers of mat a bundle of glass strands parallel in the direction scrolling of the conveyor in order to form a layer of wires having a longitudinal orientation.
• This embodiment of the invention is particularly advantageous for producing masts according to the invention having two preferential directions of orientation of the wires and being similar to grids.
• the wires arranged longitudinally are for example simple wires or rovings wires which are unwound on the conveyor from a beam and which are kept spaced from a few millimeters to a few centimeters.
• a size is deposited on the filaments during drawing in order to protect in particular the threads against abrasion and a binder is sprayed onto at least part of the threads distributed on the conveyor in order to contribute in particular to obtaining good cohesion within the mat formed, the size and the binder being subsequently polymerized and / or crosslinked.
• the present invention also relates to a device for implementing the method according to the invention.
• This device comprises at least one drawing wheel whose rotary movement relative to its axis is provided by a first motor and at least one projection wheel whose rotary movement relative to its axis is synchronized with respect to the movement of the wheel and whose movement relative to the axis of the drawing wheel is ensured by a servomotor.
• FIG. 1 represents a schematic view of a device for implementing the method according to the invention, the stretching system and the projection member being seen from the front,
• FIG. 2 represents a schematic side view of the stretching system and of the projection member symbolically represented in FIG. 1.
• a multiplicity of filaments of molten glass in the form of a layer of filaments is drawn from the orifices (2) of a die (1) filaments (3), then the filaments are coated with a sizing composition protecting them in particular from abrasion, using a sizing device (4) before gathering the filaments into son (5).
• the wires after passing over a guide wheel (6) and a idler wheel (7) are driven by the rotating drawing wheel (8) in rotation (symbolized by a simple arrow) then ejected from this wheel at a point which moves at the periphery of the wheel in an arc (flapping movement symbolized by a double arrow).
• the ejection is effected by means of the fins (9) of the projection wheel (1 0) (also called “impeller") located inside the drawing wheel and moving inside of said wheel, the fins passing through slots (1 1) on the surface of the stretching wheel.
• the wires are projected tangentially to the drawing wheel and following the flapping movement of the projection wheel. The projected wires are thus distributed on a conveyor
• the stretching wheel (used to stretch and drive the wires) is generally equipped with an independent movable rear plate (1 3) on which the projection wheel (1 0) is fixed, the servomotor (1 4) driving the plate rear and thus the projection wheel in a flapping motion.
• the servomotor can be mounted "on" the axis of the drawing wheel (the movement can possibly be transmitted by simple mechanical means, in particular a rod of simple shape (1 5)) just like the first motor used to drive the stretching wheel (the movement possibly being transmitted by a simple means such as a belt (1 6)) and, if necessary, the rotating projection wheel (the rotary movement then being transmitted to this last wheel by mechanical means such as a belt (1 7) and thus being synchronized with the rotational movement of the drawing wheel).
• the device according to the invention can also comprise a servo module and / or a programmable control system for the servomotor (s), and can comprise one or more other members chosen from those usually used in devices for producing masts.
• a servo module and / or a programmable control system for the servomotor (s) can comprise one or more other members chosen from those usually used in devices for producing masts.
• at least two offset dies are used which are arranged on either side of the conveyor, each die being associated with a drawing system and with its own projection member, each projection member being controlled by an independent servomotor.
• the mats according to the invention can be used to make composites. Several mats can in particular be stacked, with the same orientation or different orientations (in particular by crossing them at 90 °), and be preformed to give reinforcements to the shape of the part to be molded.
• the composites produced comprise at least one mat according to the invention and at least one organic material.
• the composites produced from the mats according to the invention have properties superior to the composites produced from isotropic mats or anisotropic mats having a low rate of oriented yarns, in at least one direction.
• the following examples illustrate the present invention without, however, limiting it.
• the tensile breaking stress, the flexural breaking stress and the notched Charpy impact resistance of this composite are measured according to ISO R 527, ISO R 1 78 and ISO R 1 79 standards.
• the tensile strength of the composite measured in any direction in the plane of the composite is approximately 1 45 MPa.
• the bending breaking stress of the composite measured in any direction in the plane of the composite is 300 MPa.
• the notched Charpy impact strength of the composite measured in any direction in the plane of the composite is 85 kJ / m 2 .
• the procedure is as in the reference example by replacing the four isotropic mats with four mats of the same grammage (450 g / m 2 ) each having 80% by weight of wires oriented in a preferential transverse direction, the mats being stacked so as to have the same preferential orientation within the composite.
• the tensile stress of the composite measured in the preferred direction of orientation of the wires is approximately 21 5 MPa and that measured in the direction perpendicular to the preferred direction (in the plane of the composite) is approximately 45 MPa.
• the bending breaking stress of the composite measured in the preferred direction of orientation of the wires is approximately 530 MPa and that measured in the direction perpendicular to the preferred direction (in the plane of the composite) is approximately 105 MPa.
• the notched Charpy impact resistance measured in the direction of preferential orientation of the wires is approximately 205 kJ / m 2 and that measured in the direction perpendicular to the preferential direction (in the plane of the composite) is around 40 kJ / m 2 .
• Example 1 The procedure is as in Example 1 by making a rotation of 90 ° to two of the mats in the plane of the composite.
• the tensile strength of the composite measured in the preferred direction of orientation of the wires of two of the masts or in the direction perpendicular (in the plane of the composite) to this preferred direction is approximately 1 60 MPa.
• the bending breaking stress of the composite measured in the preferred direction of orientation of the wires of two of the mats or in the direction perpendicular (in the plane of the composite) to this preferred direction is approximately 320 MPa.
• the notched Charpy impact resistance measured in the preferred direction of orientation of the wires of two of the masts or in the direction perpendicular (in the plane of the composite) to this preferred direction is approximately 1 0 0 kJ / m 2 .
• the masts according to the invention can be used to reinforce bumpers of motor vehicles, rear shelves of motor vehicles, etc.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Nonwoven Fabrics (AREA)
• Laminated Bodies (AREA)
• Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
• Woven Fabrics (AREA)
• Joining Of Glass To Other Materials (AREA)
• Glass Compositions (AREA)
• Reinforced Plastic Materials (AREA)
• Medicines Containing Plant Substances (AREA)

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• 1996
  • 1996-09-06 FR FR9610888A patent/FR2753207B1/fr not_active Expired - Fee Related
• 1997
  • 1997-09-04 KR KR1019980703285A patent/KR20000064327A/ko not_active Ceased
  • 1997-09-04 ES ES97938978T patent/ES2176775T3/es not_active Expired - Lifetime
  • 1997-09-04 DE DE69712862T patent/DE69712862T2/de not_active Expired - Lifetime
  • 1997-09-04 BR BR9706710A patent/BR9706710A/pt not_active Application Discontinuation
  • 1997-09-04 EP EP97938978A patent/EP0859882B1/de not_active Expired - Lifetime
  • 1997-09-04 DK DK97938978T patent/DK0859882T3/da active
  • 1997-09-04 AU AU41224/97A patent/AU731107C/en not_active Ceased
  • 1997-09-04 PT PT97938978T patent/PT859882E/pt unknown
  • 1997-09-04 WO PCT/FR1997/001556 patent/WO1998010131A1/fr not_active Ceased
  • 1997-09-04 NZ NZ330156A patent/NZ330156A/xx unknown
  • 1997-09-04 CA CA002236841A patent/CA2236841A1/fr not_active Abandoned
  • 1997-09-04 AT AT97938978T patent/ATE218172T1/de not_active IP Right Cessation
  • 1997-09-04 JP JP51230598A patent/JP4114954B2/ja not_active Expired - Lifetime
• 1998
  • 1998-04-30 NO NO981972A patent/NO981972D0/no not_active Application Discontinuation

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