WO2005091715A2

WO2005091715A2 - Improved pre-impregnated materials and apparatus and methods for manufacture thereof

Info

Publication number: WO2005091715A2
Application number: PCT/IL2005/000337
Authority: WO
Inventors: Eran Werner
Original assignee: Pc Composites Ltd.
Priority date: 2004-03-25
Filing date: 2005-03-24
Publication date: 2005-10-06
Also published as: WO2005091715A3

Abstract

A method for manufacture of a pre-impregnated product including causing a substrate moving at a linear speed of at least 100 meters per minute to generally horizontally traverse a first coating stage at which impregnation particles are caused to be deposited onto a first surface thereof, thereafter causing the substrate moving at a linear speed of at least 100 meters per minute to generally horizontally traverse a first heated pressing stage at which the impregnation particles are caused to be impregnated into the substrate from the first surface, thereafter causing the substrate moving at a linear speed of at least 100 meters per minute to generally horizontally traverse a second coating stage at which impregnation particles are caused to be deposited onto a second surface thereof and thereafter causing the substrate moving at a linear speed of at least 100 meters per minute to generally horizontally traverse a second heated pressing stage at which the impregnation particles are caused to be impregnated into the substrate from the second surface.

Description

IMPROVED PRE-IMPREGNATED MATERIALS AND APPARATUS AND METHODS FOR MANUFACTURE THEREOF

REFERENCE TO RELATED APPLICATIONS

Reference is made to the following co-pending applications, the disclosures of which are hereby incorporated by reference: U.S. Patent Application Serial No. 10/ 489,080, filed March 5, 2004, entitled "ELECTROSTATIC COATER AND METHOD FOR FORMING PREPREGS THEREWITH" which is a national phase of PCT Application PCT/IL02/00763; U.S. Patent Application Serial No. 10/809,284, filed March 25, 2004, entitled "IMPROVED PRE-IMPREGNATED MATERIALS" convention priority of which is hereby claimed under pursuant to 37 C.F.R. 1.78(a)(1), U.S. Provisional Patent Application filed January 5, 2005, entitled "IMPROVED PRE- LMPREGNATED MATERIALS" convention priority of which is hereby claimed pursuant to 37 C.F.R. 1.78(a)(4) and (5)(i).

FIELD OF THE INVENTION

The present invention relates generally to a system and method for preparation of improved pre-impregnated materials and to materials produced thereby.

BACKGROUND OF THE INVENTION

The following U.S. Patents are believed to represent the current state of the art U.S. Patents 6,656,316; 6,620,243; 5,911,932; 5,895,622; 5,820,941; 5,80O,615_; 5,639,307; 5,409,757; 5,360,661; 5,310,582; 5,302,419; 5,296,064; 5,198,281 5,171,630; 5,094,883 and 4,634,058. SUMMARY OF THE INVENTION

The present invention seeks to provide an improved system and method for preparation of pre-impregnated materials. There is thus provided in accordance with a preferred embodiment of the present invention a method for manufacture of a pre- impregnated product including causing a substrate moving at a linear speed of at least 100 meters per minute to generally horizontally traverse a first coating stage at which impregnation particles are caused to be deposited onto a first surface thereof, thereafter causing the substrate moving at a linear speed of at least 100 meters per minute to generally horizontally traverse a first heated pressing stage at which the impregnation particles are caused to be impregnated into the substrate from the first surface, thereafter causing the substrate moving at a linear speed of at least 100 meters per minute to generally horizontally traverse a second coating stage at which impregnation particles are caused to be deposited onto a second surface thereof and thereafter causing the substrate moving at a linear speed of at least 100 meters per minute to generally horizontally traverse a second heated pressing stage at which the impregnation particles are caused to be impregnated into the substrate from the second surface. In accordance with a preferred embodiment of the present invention the method for manufacture of a pre-impregnated product also includes the step of reversing the orientation of the substrate between the first heated pressing stage and the second coating stage. Preferably, at least one of the first and second coating stages includes coating the substrate with electrostatically charged particles supplied from a plurality of nozzles, each extending at least along the entire width of the substrate. In accordance with another preferred embodiment of the present invention at least one of the first and second coating stages includes coating the substrate with electrostatically charged particles supplied from a plurality of nozzles, each extending at least along the entire width of the substrate generally perpendicularly to a direction of movement of the substrate relative thereto. Preferably, the impregnation particles include particles selected from the group consisting of: a thermoplastic material, a thermosetting material, an epoxy, a phenolic material, a polyimide, chalk, talk, a ceramic material, a glass material, organic pigments and inorganic pigments. More preferably, at least one of the thermoplastic material and the thermosetting material includes particles selected from the group consisting of: PP, PA, PPS, PEEK, PEKK, PBT, PEI and PAL In accordance with yet another preferred embodiment of the present invention the substrate includes a material selected from the group consisting of: paper, cardboard, rubber, metal foil, a woven material, a non-woven material, a perforated material, a non- perforated material, a natural material, an organic material, a tow formed of fibers and a yarn formed of fibers. Preferably, the metal foil includes at least one of an aluminum foil and a copper foil. Additionally or alternatively, the fiber includes a material selected from a group consisting of: carbon fiber, glass fiber and metal fiber. There is also provided in accordance with another preferred embodiment of the present invention apparatus for manufacture of a pre-impregnated product including a substrate driver causing a substrate to move horizontally at a linear speed of at least 100 meters per minute, a first coating assembly, traversed by the substrate at a linear speed of at least 100 meters per minute, operative to deposit impregnation particles onto a first surface of the substrate, a first heated pressing assembly, traversed by the substrate at a linear speed of at least 100 meters per minute, operative to impregnate the impregnation particles into the substrate from the first surface, a second coating assembly, traversed by the substrate at a linear speed of at least 100 meters per minute, operative to deposit impregnation particles onto a second surface of the substrate and a second heated pressing assembly, traversed by the substrate at a linear speed of at least 100 meters per minute, operative to impregnate the impregnation particles into the substrate from the second surface. In accordance with a preferred embodiment of the present invention the apparatus for manufacture of a pre-impregnated product also includes a substrate orientation reverser for reversing the orientation of the substrate between the first heated pressing assembly and the second coating assembly. Preferably, at least one of the first and second coating assemblies includes a plurality of nozzles, each the nozzle extending at least along the entire width of the substrate, and wherein the at least one of the first and second coating assemblies is operative to coat the substrate with electrostatically charged particles supplied from the plurality of nozzles. In accordance with another preferred embodiment of the present invention at least one of the first and second coating assemblies includes a plurality of nozzles each extending at least along the entire width of the substrate generally perpendicularly to a direction of movement of the substrate relative thereto, and wherein the at least one of the first and second coating assemblies is operative to coat the substrate with electrostatically charged particles supplied from the plurality of nozzles. Preferably, the impregnation particles include particles selected from the group consisting of: a thermoplastic material, a thermosetting material, an epoxy, a phenolic material, a polyimide, chalk, talk, a ceramic material, a glass material, organic pigments and inorganic pigments. More preferably, at least one of the thermoplastic material and the thermosetting material includes particles selected from the group consisting of: PP, PA, PPS, PEEK, PEKK, PBT, PEI and PAL In accordance with yet another preferred embodiment of the present invention the substrate includes a material selected from the group consisting of: paper, cardboard, rubber, metal foil, a woven material, a non- woven material, a perforated material, a non- perforated material, a natural material, an organic material, a tow formed of fibers and a yarn formed of fibers. Preferably, the metal foil includes at least one of an aluminum foil and a copper foil. Additionally or alternatively, the fiber includes a material selected from a group consisting of: carbon fiber, glass fiber and metal fiber. There is additionally provided in accordance with yet another preferred embodiment of the present invention a pre-impregnated material including a textile substrate and an impregnation particle layer adhered to the textile substrate, the pre- impregnated material being characterized in that the impregnation particle layer has a uniformity of thickness having a variation of less than 5% of its average thickness. There is further provided in accordance with a further preferred embodiment of the present invention a pre-impregnated material including a textile substrate and an impregnation particle layer adhered to the textile substrate, the pre-impregnated material being characterized in that the impregnation particle layer has an impregnation depth of at least 60% of the thickness of the textile substrate. There is still further provided in accordance with yet a further preferred embodiment of the present invention a pre-impregnated material including a textile substrate and an impregnation particle layer adhered to the textile substrate, the pre- impregnated material being characterized in that the impregnation particle layer has a thickness exceeding 300 microns. There is additionally provided in accordance with another preferred embodiment of the present invention a pre-impregnated material including a textile substrate and an impregnation particle layer adhered to the textile substrate, the pre-impregnated material being characterized in that the weight of the impregnation particle layer is at least 70% of the weight of the pre-impregnated material. There is also provided in accordance with yet another preferred embodiment of the present invention a pre-impregnated material including a textile substrate and an impregnation particle layer adhered to the textile substrate, the pre-impregnated material being characterized in that the impregnation particle layer has a thickness less than 50 microns. There is further provided in accordance with still another preferred embodiment of the present invention a pre-impregnated material including a textile substrate and an impregnation particle layer adhered to the textile substrate, the pre-impregnated material being characterized in that the weight of the impregnation particle layer is less than 10% of the weight of the pre-impregnated material. In accordance with a preferred embodiment of the present invention the weight of the impregnation particle layer is less than 5% of the weight of the pre-impregnated material. There is also provided in accordance with another preferred embodiment of the present invention a pre-impregnated material including a textile substrate and an impregnation particle layer adhered to the textile substrate, the pre-impregnated material being characterized in that the impregnation particle layer includes particles having a size spectrum which extends over at least two orders of magnitude. There is further provided in accordance with a further preferred embodiment of the present invention a pre-impregnated material including a textile substrate and an impregnation particle layer adhered to the textile substrate, the pre-impregnated material being characterized in that the impregnation particle layer includes particles having a density spectrum which extends over at least one order of magnitude. In accordance with a preferred embodiment of the present invention the impregnation particle layer has an impregnation depth of at least 60% of the thickness of the textile substrate. Preferably, the impregnation particle layer has an impregnation depth of at least 80% of the thickness of the textile substrate. In accordance with another preferred embodiment of the present invention the impregnation particle layer has a uniformity of thickness having a variation of less than 5% of its average thickness. Preferably, the impregnation particle layer has a uniformity of thickness having a variation of less than 2% of its average thickness. Additionally or alternatively, the impregnation particle layer has a uniformity of thickness having a variation of less than 2% of its average thickness along its width. I-n accordance with still another preferred embodiment of the present invention the impregnation particle layer is fully melted. Alternatively, the impregnation particle layer is partially melted and partially in particulate form. Preferably, the impregnation particle layer is formed as a plurality of impregnation particle layers. In accordance with a further preferred embodiment of the present invention different ones of the plurality of impregnation particle layers have different thicknesses. Additionally or alternatively, different ones of the plurality of impregnation particle layers are formed of different impregnation particle materials. There is also provided in accordance with another preferred embodiment of the present invention a laminate formed of a plurality of layers of pre-impregnated material, at least one of the plurality of layers of pre-impregnated material including a textile substrate and an impregnation particle layer adhered to the textile substrate, the pre- impregnated material being characterized in that the impregnation particle layer has a uniformity of thickness having a variation of less than 5% of its average thickness. There is additionally provided in accordance with another preferred embodiment of the present invention a laminate formed of a plurality of layers of pre-impregnated material, at least one of the plurality of layers of pre-impregnated material including a textile substrate and an impregnation particle layer adhered to the textile substrate, the pre-impregnated material being characterized in that the impregnation particle layer has a thickness exceeding 300 microns. There is further provided in accordance with yet another preferred embodiment of the present invention a laminate formed of a plurality of layers of pre-impregnated material, at least one of the plurality of layers of pre-impregnated material including a textile substrate and an impregnation particle layer adhered to the textile substrate, the pre-impregnated material being characterized in that the weight of the impregnation particle layer is at least 70% of the weight of the pre-impregnated material. There is further provided in accordance with a further preferred embodiment of the present invention a laminate formed of a plurality of layers of pre-impregnated material, at least one of the plurality of layers of pre-impregnated material including a textile substrate and an impregnation particle layer adhered to the textile substrate, the pre-impregnated material being characterized in that the impregnation particle layer has a thickness less than 50 microns. There is still further provided in accordance with still another preferred embodiment of the present invention a laminate formed of a plurality of layers of pre- impregnated material, at least one of the plurality of layers of pre-impregnated material including a textile substrate and an impregnation particle layer adhered to the textile substrate, the pre-impregnated material being characterized in that the weight of the impregnation particle layer is less than 10% of the weight of the pre-impregnated material. There is also provided in accordance with another preferred embodiment of the present invention a laminate formed of a plurality of layers of pre-impregnated material, at least one of the plurality of layers of pre-impregnated material including a textile substrate and an impregnation particle layer adhered to the textile substrate, the pre- impregnated material being characterized in that the impregnation particle layer includes particles having a size spectrum which extends over at least two orders of magnitude. There is additionally provided in accordance with a further preferred embodiment of the present invention a laminate formed of a plurality of layers of pre- impregnated material, at least one of the plurality of layers of pre-impregnated material including a textile substrate and an impregnation particle layer adhered to the textile substrate, the pre-impregnated material being characterized in that the impregnation particle layer includes particles having a density spectrum which extends over at least one order of magnitude. BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which: Fig. 1 is a simplified pictorial illustration of a system for production of pre- impregnated materials constructed and operative in accordance with a preferred embodiment of the present invention; Fig. 2 is a simplified schematic illustration of the system of Fig. 1; Figs. 3A and 3B are, respectively, a simplified pictorial illustration and a simplified planar illustration of a feeder forming part of the system of Figs. 1 and 2; Figs. 4A, 4B, 4C, 4D and 4E are photomicrographs of various stages of manufacture of a paper based pre-impregnated material in accordance with the method of the present invention; Figs. 5A, 5B, 5C, 5D and 5E are photomicrographs of various stages of manufacture of a carbon fiber based pre-impregnated material in accordance with the method of the present invention; Figs. 6A, 6B, 6C, 6D and 6E are photomicrographs of various stages of manufacture of a glass fiber based pre-impregnated material in accordance with the method of the present invention; Fig. 7 is a simplified sectional illustration of a pre-impregnated material constructed and operative in accordance with a preferred embodiment of the present invention, showing uniformity of impregnation particle thickness; Fig. 8 is a simplified sectional illustration of a pre-impregnated material constructed and operative in accordance with another preferred embodiment of the present invention, showing uniformity of impregnation particle thickness; Fig. 9 is a simplified sectional illustration of a pre-impregnated material constructed and operative in accordance with a preferred embodiment of the present invention, showing impregnation depth; Fig. 10 is a simplified sectional illustration of a pre-impregnated material constructed and operative in accordance with a preferred embodiment of the present invention, showing high impregnation particle thickness; Fig. 11 is a simplified sectional illustration of a pre-impregnated material constructed and operative in accordance with a preferred embodiment of the present invention, showing low impregnation particle thickness; Fig. 12 is a simplified sectional illustration of a pre-impregnated material constructed and operative in accordance with another preferred embodiment of the present invention, showing uniformity of impregnation particle thickness; Fig. 13 . is a simplified sectional illustration of a pre-impregnated material constructed and operative in accordance with another preferred embodiment of the present invention, showing uniformity of impregnation particle thickness; Fig. 14 is a simplified sectional illustration of a pre-impregnated material constructed and operative in accordance with a preferred embodiment of the present invention, showing impregnation depth; Fig. 15 is a simplified sectional illustration of a pre-impregnated material constructed and operative in accordance with a preferred embodiment of the present invention, showing high impregnation particle thickness; Fig. 16 is a simplified sectional illustration of a pre-impregnated material constructed and operative in accordance with a preferred embodiment of the present invention, showing low impregnation particle thickness; Fig. 17 is a simplified sectional illustration of a laminate formed of a plurality of layers of pre-impregnated material constructed and operative in accordance with a preferred embodiment of the present invention; and Fig. 18 is a simplified sectional illustration of a laminate formed of a plurality of layers of pre-impregnated material constructed and operative in accordance with a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Reference is now made to Figs. 1 and 2, which are simplified illustrations of a system for production of pre-impregnated materials constructed and operative in accordance with a preferred embodiment of the present invention. As seen in Figs. 1 and

2, a substrate 10O, such as paper or cardboard, rubber, metal foil such as aluminum or copper foil, formed in any suitable manner such as woven, non-woven, perforated or non-perforated or a tow or yarn formed of fibers such as carbon, glass, metal, or natural or organic materials, is supplied typically in a roll 102 and is unrolled to lie generally in an horizontal plane as it moves, preferably at a speed of 50 to 450 meters per minute, preferably initially past a wetting station 104, which is preferably operative to wet opposite surfaces 106 and 108 of the substrate with water. Fig. 4A shows a paper substrate prior to wetting and coating. Fig. 5A shows a carbon fiber substrate prior to wetting and coating. Fig. 6A shows a glass fiber substrate prior to wetting and coating. Downstream of wetting station 104, the wetted substrate passes through a first single side coating chamber 110, which includes a first array 112 of elongate nozzles 114, which are operative to accelerate impregnation material particles into electrostatically bound engagement with the substrate 100. The substrate 100 may be electrostatically charged prior to passing through single side coating chamber 110 or may be electrically coupled to ground. Impregnation material particles are preferably sized between one micron and

200 microns and more preferably between 20 and 80 microns in diameter and may be of any suitable material, such as a thermoplastic or thermosetting material, such as for example PP, PA, PPS, PEEK, PEKK, PBT, PEI, PAI, Epoxies, Phenolics and Polyimides as well as chalk, talc, ceramic materials, glass balls and organic or inorganic pigments. Nozzles 114 are preferably constructed and operative in a manner described in Published PCT Application WO 03/024609, the disclosure of which is hereby incorporated by reference and are preferably up to 10 meters in length. The separation between adjacent nozzles may be between 0.1 and 1 meter. Preferably, each chamber includes 2 - 10 nozzles. One preferred difference in the nozzles 114, as compared with those described in Published PCT Application WO 03/024609, is that vanes 116 are preferably angled at a non-90 degree angle to the longitudinal axis of each nozzle 114. High voltage electrical power is preferably supplied by a high voltage power supply 120 to brushes witl in nozzles 114 for charging the impregnation material particles. Impregnation material particles are supplied to nozzles 114 from a screening hopper 130 via a plurality of supply conduits 132, each of which includes a pressurized air input which receives pressurized air via a pressurized air supply conduit 134 from a compressor 136. Each of supply conduits 132 feeds impregnation material particles to a nozzle feeder 140. Each nozzle 114 preferably receives impregnation material particles from a multiplicity of nozzle feeders 140 disposed therealong and typically spaced from each other by 20 centimeters. Preferably, each nozzle feeder 140 includes a pair of outlet conduits 142 which are coupled to nozzle 114, preferably at a spacing of 10 centimeters.

Each outlet conduit 142 preferably includes a pressurized air input which receives pressurized air via a pressurized air supply conduit 144 from compressor 136. The structure and operation of nozzle feeders 140 is described hereinbelow with reference to

Figs. 3A and 3B. Fig. 4B shows a paper substrate following coating on one side thereof. Fig. 5B shows a carbon fiber substrate following coating on one side thereof. Fig. 6B shows a glass fiber substrate following coating on one side thereof. Downstream of first single side coating chamber 110, the one-side coated substrate, here designated by reference numeral 150, passes through a heated pressing stage 152, here shown as a pair of belts 154 and 156, belt 154, which engages coated surface 106, being heated. Alternatively, one or more heated rollers may be employed for this purpose. Fig. 4C shows a paper substrate following coating on one side thereof and pressing. Fig. 5C shows a carbon fiber substrate following coating on one side thereof and pressing. Fig. 6C shows a glass fiber substrate following coating on one side thereof and pressing. Downstream of heated pressing stage 152, the pressed, one-side coated substrate, here designated by reference numeral 160, passes over a first comer roller 162 and moves generally vertically into engagement with a second comer roller 164 and moves horizontally downstream of second comer roller 164 preferably past a second wetting station 174, which is preferably operative to wet surface 108 of the substrate

160 with water. Downstream of wetting station 174, the wetted substrate passes through a second single side coating chamber 180, which includes a second array 182 of elongate nozzles 184, which are operative to accelerate impregnation material particles into electrostatically bound engagement with surface 108 of the pressed, one side coated substrate 160. The substrate 160 may be electrostatically charged prior to passing through single side coating chamber 180 or may be electrically coupled to ground. The impregnation material particles accelerated onto substrate 160 are preferably sized between one micron and 200 microns and more preferably between 20 and 80 microns in diameter and may be of any suitable material, such as a thermoplastic or thermosetting material, such as for example PP, PA, PPS, PEEK, PEKK, PBT, PEI, PAI, Epoxies, Phenolics and Polyimides as well as chalk, talc, ceramic materials, glass balls and organic or inorganic pigments. These particles may be identical to or different from the particles employed in first side coating chamber 110. Alternatively, second single side coating chamber 180 may be obviated or not employed and the final product may be coated with impregnation particles on only one side. According to a further alternative embodiment of the present invention, different ones of nozzles 184 may provide different types of particles. Nozzles 184 are preferably constructed and operative in a manner described in Published PCT Application WO 03/0246O9, the disclosure of which is hereby incorporated by reference and are preferably up to 10 meters in length. High voltage electrical power is preferably supplied by a high voltage power supply 190 to brushes within nozzles 184 for charging the impregnation material particles. Impregnation material particles are supplied to nozzles 184 from a screening hopper 200 via a plurality of supply conduits 202, each of which includes a pressurized air input which receives pressurized air via a pressurized air supply conduit 204 from compressor 136. Each of supply conduits 202 feeds impregnation material particles to a nozzle feeder 210. Each nozzle 184 preferably receives impregnation material particles from a multiplicity of nozzle feeders 210 disposed therealong and typically spaced from each other by 20 centimeters. Preferably, each nozzle feeder 210 includes a pair of outlet conduits 212 which are coupled to nozzle 184, preferably at a spacing of 10 centimeters. Each outlet conduit 212 preferably includes a pressurized air input which receives pressurized air via a pressurized air supply conduit 214 from compressor 136. The structure and operation of nozzle feeders 210 is described hereinbelow with reference to Figs. 3A and 3B. Fig. 4D shows a paper substrate following coating on a second side thereof. Fig. 5D shows a carbon fiber substrate following coating on a second side thereof. Fig. 6D shows a glass fiber substrate following coating on a second side thereof. Downstream of second single side coating chamber 180, the double-sided coated substrate, here designated by reference numeral 220, passes through a heated pressing stage 222, here shown as a pair of belts 224 and 226, belt 224, which engages coated surface 108, being heated. Alternatively, one or more heated rollers may be employed for this purpose. The double-sided coated, pressed product, here designated by reference numeral 230, is then rolled onto a roller 240, which is preferably driven by an electric motor drive 250, whose speed governs the speed of the entire coating process. Fig. 4E shows a double-sided coated, pressed product formed using a paper substrate. Fig. 5E shows a double-sided coated, pressed product formed using a carbon fiber substrate. Fig. 6E shows a double-sided coated, pressed product formed using a glass fiber substrate. Reference is now to Figs. 3A and 3B which illustrate a feeder 260, useful as feeders 140 and 210 in the embodiment of Figs. 1 and 2. A chassis 270, including a base 272 and a top panel 274, separated by generally vertical supports 276, surrounds a vibrated impregnation material particle container 280 having an inlet 282. An electric motor 284 mounted on top panel 274, is coupled to a transmission 286, which drives a particle feeding screw 288, extending generally vertically through container 280, which feeds impregnation material, particles into a pressurized feeding enclosure 290 from which extend nozzle feeding conduits 292, which may serve as outlet conduits 142 and 212 of the embodiments of Figs. 1 and 2. Pressurized feeding enclosure 290 preferably also receives pressurized air via a conduit 134 (Fig. 1 ) at a pressurized air inlet 294. Fixed to particle feeding screw 288, for rotation together therewith, driven by electric motor 284, is a particle mixing element 296. Vibration of vibrated impregnation material particle container 280 is produced by an electrically operated vibrator 298 mounted thereon. Vibration of the chassis 270 is reduced by vibration absorbers 300. Reference is now made to Fig. 7, which is a simplified sectional illustration of a pre-impregnated material constructed and operative in accordance with a preferred embodiment of the present invention, showing uniformity of impregnation particle thickness. As seen in Fig. 7, a web material 400 is shown impregnated with impregnation particles forming at least one impregnation particle layer 402 having a high degree of uniformity of thickness, having a variation of less than 5% and preferably approximately 1%. Web material 400 may include any suitable web material, such as paper or cardboard, rubber, metal foil such as aluminum or copper foil, formed in any suitable manner such as woven, non-woven, perforated or non-perforated or a tow or yarn formed of fibers such as carbon, glass, metal, or natural or organic materials. The illustrated embodiment includes two layers 402, on opposite surfaces of the web material 400, each layer preferably of thickness about 100 microns. The web material 400 may be any suitable type of web material, woven as shown in Fig. 7 or alternatively non- woven or formed in any other suitable manner. The term "web material" as used throughout the specification and claims, includes also an array of fibers which may or may not be interengaged and which may or may not extend along parallel directions. The array of fibers may or may not be homogeneous and may or may not include fibers of different materials and/or configurations and/or sizes. The impregnation particles may be any suitable type of impregnation particles, including, inter alia, thermoplastic or thermosetting material, such as for example PP, PA, PPS, PEEK, PEKK, PBT, PEI, PAI, Epoxies, Phenolics and Polyimides as well as chalk, talc, ceramic materials, glass balls and organic or inorganic pigments. Preferably, the impregnation particles are impregnated in the form of powders having a particle size of between 1 and 200 microns. It is seen that in the illustrated example, warp fibers 410 and weft fibers 412 and the interstices 414 therebetween each have formed thereon and therein a pair of opposite-facing impregnation particle layers 402 whose thickness is uniform to a high degree, having a variation of less than 5% and preferably approximately 1%. Typically each of warp fibers 410 and weft fibers 412 is formed of a multiplicity of individual fiber strands 416. The pre-impregnated material of Fig. 7 is preferably realized by accelerated impingement of a stream of impregnation material particles onto the web material 400 followed by the application of heat, in accordance vith the teachings of applicant/assignee's Published PCT Patent Application WO 03/024609, the disclosure of which is hereby incorporated by reference. Different materials may be impregnated, such as pigments, glass balls, metal particles which are coated or uncoated with a polymer, TEFLON®, ceramic particles and organic and inorganic particles. The same or different material may be impregnated on different sides of the web material, such as same or different pigments on the two sides, glass balls of the same or different sizes on the two sides, or the same or different metal or ceramic particles on the two sides. -Alternatively, the material may be impregnated only on one side of the web material. Reference is now made to Fig. 8, which is a simplified sectional illustration of a pre-impregnated material constructed and operative in accordance with another preferred embodiment of the present invention, showing uniformity of impregnation particles thickness. The essential difference between the embodiment of Fig. 8 and that of Fig. 7, described hereinabove, is in the amount of impregnation particles impregnated into the web material. As seen in Fig. 8, a web material 500 is shown fully impregnated with impregnation particles and forming a fully impregnated web material layer 502 having a high degree of uniformity of thickness, having a variation of less than 5% and preferably approximately 1%. The thickness is preferably about 500 microns. The web material 500 may be any suitable type of web material, woven as shown in Fig. 8 or alternatively non-woven or formed in any other suitable manner. The term "web material" includes also an array of fibers which may or may not be interengaged and which may or may not extend along parallel directions. The array of fibers may or may not be homogeneous and may or may not include fibers of different materials and/or configurations and/or sizes. The impregnation particles may be any suitable type of impregnation particles, including, inter alia, thermoplastic or thermosetting material, such as for example PP, PA, PPS, PEEK, PEKK, PBT, PEI, PAI, Epoxies, Phenolics and Polyimides as well as chalk, talc, ceramic materials, glass balls and organic or inorganic pigments. Preferably, the impregnation particles are impregnated in the form of powders having a particle size of between 1 and 200 microns. Turning to Fig. 8, it is seen that in the illustrated example, warp fibers 510 and weft fibers 512 and the interstices 514 therebetween each are fully impregnated such that layer 502 has thickness which is uniform to a high degree, having a variation of less than 5% and preferably approximately 1%. Typically each of warp fibers 510 and weft fibers 512 is formed of a multiplicity of individual fiber strands 516. It is appreciated that the embodiment of Fig. 8 is typically more rigid than the embodiment of Fig. 7. The pre-impregnated material of Fig. 8 is preferably realized by accelerated impingement of a stream of impregnation material particles onto the web material 500 followed by the application of heat, in accordance with the teachings of applicant/assignee's Published PCT Patent Application WO 03/024609, the disclosure of which is hereby incorporated by reference. Reference is now made to Fig. 9, which is a simplified sectional illustration of a pre-impregnated material constructed and operative in accordance with another preferred embodiment of the present invention. The difference between the embodiment of Fig. 9 and that of Fig. 7, described hereinabove, is in the fact that the web material is coated only on one side thereof. As seen in Fig. 9, similarly to that described hereinabove with reference to Fig. 7, a web material 600 is shown impregnated with impregnation particles forming an impregnation particle layer 602 having a high degree of uniformity of thickness, having a variation of less than 5% and preferably approximately 1%. The illustrated embodiment includes a single layer 602, typically of thickness approximately 200 microns. The web material 600 may be any suitable type of web material, woven as shown in Fig. 9 or alternatively non-woven or formed in any other suitable manner. The term "web material" as used throughout the specification and claims, includes also an array of fibers which may or may not be interengaged and which may or may not extend along parallel directions. The array of fibers may or may not be homogeneous and may or may not include fibers of different materials and/or configurations and/or sizes. The impregnation particles may be any suitable type of impregnation particles, including, inter alia, thermoplastic or thermosetting material, such as for example PP, PA, PPS, PEEK, PEKK, PBT, PEI, PAI, Epoxies, Phenolics and Polyimides as well as chalk, talc, ceramic materials, glass balls and organic or inorganic pigments. Preferably, the impregnation particles are impregnated in the form of powders having a particle size of between 1 and 200 microns. It is seen that in the illustrated example, warp fibers 610 and weft fibers 612 and the interstices 614 therebetween each have formed thereon and therein a impregnation particle layer 602 whose thickness is uniform to a high degree, having a variation of less than 5% and preferably approximately 1%. Typically each of warp fibers 610 and weft fibers 612 is formed of a multiplicity of individual fiber strands 616. The pre-impregnated material of Fig. 9 is preferably realized by accelerated impingement of a stream of impregnation material particles onto the web material 600 followed by the application of heat, in accordance with the teachings of applicant/assignee's Published PCT Patent Application WO 03/024609, the disclosure of which is hereby incorporated by reference. Reference is now made to Fig. 10, which is a simplified sectional illustration of a pre-impregnated material constructed and operative in accordance with a preferred embodiment of the present invention, showing high impregnation particle thickness. The essential difference between Fig. 10 and Fig. 8 described hereinabove lies in the overall impregnation particle thickness. As seen in Fig. 10, a web material 700 is shown fully impregnated with impregnation particles and forming a fully impregnated web material layer 702 having a high degree of uniformity of thickness, having a variation of less than 5% and preferably approximately 1%. The thickness is preferably above 500 microns and may reach up to approximately 6mm. The web material 700 may be any suitable type of web material, woven as shown in Fig. 10 or alternatively non- woven o>x formed in any other suitable manner. The term "web material" includes also an array of fibers which may or may not be interengaged and which may or may not extend, along parallel directions. The array of fibers may or may not be homogeneous and may or may not include fibers of different materials and/or configurations and/or sizes. The impregnation particles may be any^" suitable type of impregnation particles, including, inter alia, thermoplastic or thermosetting material, such as for example PP, PA, PPS, PEEK, PEKK, PBT, PEI, PAI, Epoxies, Phenolics and Polyimides as well as chalk, talc, ceramic materials, glass balls and organic or inorganic pigments. Preferably, the impregnation particles are impregnated in the form of powders having a particle size of between 1 and 200 microns. Turning to Fig. 10, it is seen that in the illustrated example, warp fibers 710 and weft fibers 712 and the interstices 714 therebetween each are fully impregnated and an additional impregnation particle layer is formed thereover, preferably on both surfaces of the web material, such that layer 702 has thickness which is uniform to a high degree, having a variation of less than 5% and preferably approximately 1%. Typically each of warp fibers 710 and weft fibers 712 is formed of a multiplicity of individual fiber strands 716. The pre-impregnated material of Fig. 10 is preferably realized by accelerated impingement of a stream of impregnation material particles onto the web material 700 followed by the application of heat, in accordance with the teachings of applicant/assignee's Published PCT Patent Application WO 03/024609, the disclosure of which is hereby incorporated by reference. Reference is now made to Fig. 11, which is a simplified sectional illustration of a pre-impregnated material constructed and operative in accordance with a preferred embodiment of the present invention, showing a relatively low impregnation particles thickness. The essential difference between the embodiment of Fig. 11 and that of Fig. 7, described hereinabove, is in the amount of impregnation particles impregnated into the web material. In the embodiment of Fig. 11, a relatively small amount of impregnation particles is impregnated into the web material, producing relatively thin, but highly uniform, layers of impregnation particles. As seen in Fig. 11, a web material 800 is shown impregnated with impregnation particles forming at least one impregnation particle layer 802 having a high degree of uniformity of thickness, having a variation of less than 5% and preferably approximately 1%. The illustrated embodiment includes two layers 802, on opposite surfaces of the web material 800, each layer preferably of thickness about 30 microns. The web material 800 may be any suitable type of web material, woven as shown in Fig. 11 or alternatively non- woven or formed in any other suitable manner. The term "web material" as used throughout the specification and claims, includes also an array of fibers which may or may not be interengaged and wbdch may or may not extend along parallel directions. The array of fibers may or may not be homogeneous and may or may not include fibers of different materials and/or configurations and/or sizes. The impregnation particles may be any suitable type of itrxpregnation particles, including, inter alia, thermoplastic or thermosetting material, such, as for example PP, PA, PPS, PEEK, PEKK, PBT, PEI, PAI, Epoxies, Phenolics and Polyimides as well as chalk, talc, ceramic materials, glass balls and organic or inorganic pigments. Preferably, the impregnation particles are impregnated in the form of powders k-aving a particle size of between 1 and 200 microns. It is seen that in the illustrated example, warp fibers 810 and weft fibers 812 and the interstices 814 therebetween each have formed thereon and therein a pair of opposite-facing impregnation particle layers 802 whose thickness is uniform to a high degree, having a variation of less than 5% and preferably approximately 1%. Typically each of warp fibers 810 and weft fibers 812 is formed of a multiplicity of individual fiber strands 816. The pre-impregnated material of Fig. 11 is preferably realized by accelerated impingement of a stream of impregnation material particles onto tlie web material 800 followed by the application of heat, in accordance with the teachings of applicant/assignee's Published PCT Patent Application WO 03/024609, the disclosure of which is hereby incorporated by reference. Reference is now made to Fig. 12 - 16, which are similar- to Figs. 7 - 11, but differ therefrom in that a lesser amount of heat has been applied to the impregnation particles following impregnation of the web material, thereby producing a partially- particulate, partially melted impregnation particle matrix, as distinguished from a fully melted impregnation particle matrix in the embodiments of Figs. 7 - 11. In the embodiments of Figs. 13 - 17, the impregnation particles layer lie outside of the web material to a somewhat greater degree than in the embodiments of Figs. 7 - 11. Reference is now made to Fig. 12, which is a simplified sectional illustration of a pre-impregnated material constructed and operative in accordance with a preferred embodiment of the present invention, showing uniformity of impregnation particle thickness. As seen in Fig. 12, a web material 900 is shown impregnated with impregnation particles forming at least one impregnation particle layer 902 having a high degree of uniformity of thickness, having a variation of less than 5% and preferably approximately 1%. The illustrated embodiment includes two layers 902, on opposite surfaces of the web material 900, each layer preferably of thickness about 100 microns. The web material 900 may be any suitable type of web material, woven as shown in Fig. 12 or alternatively non- woven or formed in any other suitable manner. The term "web material" as used throughout the specification and claims, includes also an array of fibers which may or may not be interengaged and which may or may not extend along parallel directions. The array of fibers may or may not be homogeneous and may or may not include fibers of different materials and/or configurations and/or sizes. The impregnation particles may be any suitable type of impregnation particles, including, inter alia, thermoplastic or thermosetting material, such as for example PP, PA, PPS, PEEK, PEKK, PBT, PEI, PAI, Epoxies, Phenolics and Polyimides as well as chalk, talc, ceramic materials, glass balls and organic or inorganic pigments. Preferably, the impregnation particles are impregnated in the form of powders having a particle size of between 1 and 200 microns. It is seen that in the illustrated example, warp fibers 910 and weft fibers 912 and the interstices 914 therebetween each have formed thereon and therein a pair of opposite-facing impregnation particle layers 902 whose thickness is uniform to a high degree, having a variation of less than 5% and preferably approximately 1%. Typically each of warp fibers 910 and weft fibers 912 is formed of a multiplicity of individual fiber strands 916. The pre-impregnated material of Fig. 12 is preferably realized by accelerated impingement of a stream of impregnation material particles onto the web material 900 followed by the application of heat, in accordance with the teachings of applicant/assignee's Published PCT Patent Application WO 03/024609, the disclosure of which is hereby incorporated by reference. As noted above, in the embodiments of Figs. 12 - 16, the impregnation particle layers lie outside of the web material to a somewhat greater degree than in the embodiments of Figs. 7 - 11. In the above-described embodiment of Fig. 12, it is seen that approximately 60% of the thickness of each of the impregnation particles layer 902 lies outside of the web material, while in Fig. 7 approximately 40% of the impregnation particle layers 402 lies outside the web material. Reference is now made to Fig. 13, which is a simplified sectional illustration of a pre-impregnated material constructed and operative in accordance with another preferred embodiment of the present invention, showing uniformity of impregnation particle thickness. The essential difference between the embodiment of Fig. 13 and that of Fig. 12, described hereinabove, is in the amount of impregnation particles impregnated into the web material. As seen in Fig. 13, a web material 1000 is shown fully impregnated with impregnation particles and forming a fully impregnated web material layer 1002 having a high degree of uniformity of thickness, having a variation of less than 5% and preferably approximately 1%. The thickness is preferably about 500 microns. The web material 1000 may be any suitable type of web material, woven as shown in Fig. 13 or alternatively non- woven or formed in any other suitable manner. The term "web material" includes also an array of fibers which may or may not be interengaged and which may or may not extend along parallel directions. The array of fibers may or may not be homogeneous and may or may not include fibers of different materials and/or configurations and/or sizes. The impregnation particles may be any suitable type of impregnation particles, including, inter alia, thermoplastic or thermosetting material, such as for example PP, PA, PPS, PEEK, PEKK, PBT, PEI, PAI, Epoxies, Phenolics and Polyimides as well as chalk, talc, ceramic materials, glass balls and organic or inorganic pigments. Preferably, the impregnation particles are impregnated in the form of powders having a particle size of between 1 and 200 microns. Turning to Fig. 13, it is seen that in the illustrated example, warp fibers 1010 and weft fibers 1012 and the interstices 1014 therebetween each are fully impregnated

^• such that layer 1002 has thickness which is uniform to a high degree, having a variation of less than 5% and preferably approximately 1%. Typically each of warp fibers 1010 and weft fibers 1012 is formed of a multiplicity of individual fiber strands 1016. It is appreciated that the embodiment of Fig. 13 is typically more rigid than the embodiment of Fig. 12. The pre-impregnated material of Fig. 13 is preferably realized by accelerated impingement of a stream of impregnation material particles onto the web material 1000 followed by the application of heat, in accordance with the teachings of applicant/assignee's Published PCT Patent Application WO 03/024609, the disclosure of which is hereby incorporated by reference. Reference is now made to Fig. 14, which is a simplified sectional illustration of a pre-impregnated material constructed and operative in accordance with another preferred embodiment of the present invention. The difference between the embodiment of Fig. 14 and that of Fig. 12, described hereinabove, is in the fact that the web material is coated only on one side thereof. As seen in Fig. 14, similarly to that described hereinabove with reference to Fig. 12, a web material 1100 is shown impregnated with impregnation particles forming an impregnation particle layer 1102 having a high degree of uniformity of thickness, having a variation of less than 5% and preferably approximately 1%. The illustrated embodiment includes a single layer 1102, typically of thickness approximately 200 microns. The web material 1100 may be any suitable type of web material, woven as shown in Fig. 14 or alternatively non- woven or formed in any other suitable manner. The term "web material" as used throughout the specification and claims, includes also an array of fibers which may or may not be interengaged and which may or may not extend along parallel directions. The array of fibers may or may not be homogeneous and may or may not include fibers of different materials and/or configurations and/or sizes. The impregnation particles may be any suitable type of impregnation particles, including, inter alia, thermoplastic or thermosetting material, such as for example PP, PA, PPS, PEEK, PEKK, PBT, PEI, PAI, Epoxies, Phenolics and Polyimides as well as chalk, talc, ceramic materials, glass balls and organic or inorganic pigments. Preferably, the impregnation particles are impregnated in the form of powders having a particle size of between 1 and 200 microns. It is seen that in the illustrated example, warp fibers 1110 and weft fibers 1112 and the interstices 1114 therebetween each have formed thereon and therein an impregnation particle layer 1102 whose thickness is uniform to a high degree, having a variation of less than 5% and preferably approximately 1%. Typically each of warp fibers 1110 and weft fibers 1112 is formed of a multiplicity of individual fiber strands 1116. The pre-impregnated material of Fig. 14 is preferably realized by accelerated impingement of a stream of impregnation material particles onto the web material 1100 followed by the application of heat, in accordance with the teachings of applicant/assignee's Published PCT Patent Application WO 03/024609, the disclosure of which is hereby incorporated by reference. As noted above, in the embodiments of Figs. 12 - 16, the impregnation particle layers lie outside of the web material to a somewhat greater degree than in the embodiments of Figs. 7 - 11. In the above-described embodiment of Fig. 14, it is seen that approximately 60% of the thickness of each of the impregnation particle layers 1102 lies outside of the web material, while in Fig. 9 approximately 40% of the impregnation particle layers 602 lies outside the web material. Reference is now made to Fig. 15, which is a simplified sectional illustration of a pre-impregnated material constracted and operative in accordance with a preferred embodiment of the present invention, showing high impregnation particle thickness. The essential difference between Fig. 15 and Fig. 13 described hereinabove lies in the overall impregnation particle thickness. As seen in Fig. 15, a web material 1200 is shown fully impregnated with impregnation particles and forming a fully impregnated web material layer 1202 having a high degree of uniformity of thickness, having a variation of less than 5% and preferably approximately 1%. The thickness is preferably above 500 microns and may reach up to approximately 6mm. The web material 1200 may be any suitable type of web material, woven as shown in Fig. 15 or alternatively non- woven or formed in any other suitable manner. The term "web material" includes also an array of fibers which may or may not be interengaged and which may or may not extend along parallel directions. The array of fibers may or may not be homogeneous and may or may not include fibers of different materials and/or configurations and/or sizes. The impregnation particles may be any suitable type of impregnation particles, including, inter alia, thennoplastic or thermosetting material, such as for example PP, PA, PPS, PEEK, PEKK, PBT, PEI, PAI, Epoxies, Phenolics and Polyimides as well as chalk, talc, ceramic materials, glass balls and organic or inorganic pigments. Preferably, the impregnation particles are impregnated in the form of powders having a particle size of between 1 and 200 microns. Turning to Fig. 15, it is seen that in the illustrated example, warp fibers 1210 and weft fibers 1212 and the interstices 1214 therebetween each are fully impregnated and an additional impregnation particle layer is formed thereover, preferably on both surfaces of the web material, such that layer 1202 has thickness which is uniform to a high degree, having a variation of less than 5% and preferably approximately 1%. Typically each of warp fibers 1210 and weft fibers 1212 is formed of a multiplicity of individual fiber strands 1216. The pre-impregnated material of Fig. 15 is preferably realized by accelerated impingement of a stream- of impregnation material particles onto the web material 1200 followed by the application of heat, in accordance with the teachings of applicant/assignee's Published PCT Patent Application WO 03/024609, the disclosure of which is hereby incorporated by reference. Reference is now made to Fig. 16, which is a simplified sectional illustration of a pre-impregnated material constructed and operative in accordance with a preferred embodiment of the present invention, showing a relatively low impregnation particle thickness. The essential difference between the embodiment of Fig. 16 and that of Fig. 11, described hereinabove, is in the amount of impregnation particles impregnated into the web material. In the embodiment of Fig. 16, a relatively small amount of impregnation particles is impregnated into the web material, producing relatively thin, but highly uniform layers of impregnation particles. As seen in Fig. 16, a web material 1300 is shown impregnated with a impregnation particles forming at least one impregnation particle layer 1302 having a high degree of uniformity of thickness, having a variation of less than 5% and preferably approximately 1%. The illustrated embodiment includes two layers 1302, on opposite surfaces of the web material 1300, each layer preferably of thickness about 30 microns. The web material 1300 may be any suitable type of web material, woven as shown in Fig. 16 or alternatively non- woven or formed in any other suitable manner. The term "web material" as used throughout the specification and claims, includes also an array of fibers which may or may not be interengaged and which may or may not extend along parallel directions. The array of fibers may or may not be homogeneous and may or may not include fibers of different materials and/or configurations and/or sizes. The impregnation particles may be any suitable type of impregnation particles, including, inter alia, thermoplastic or thermosetting material, such as for example PP, PA, PPS, PEEK, PEKK, PBT, PEI, PAI, Epoxies, Phenolics and Polyimides as well as chalk, talc, ceramic materials, glass balls and organic or inorganic pigments. Preferably, the impregnation particles are impregnated in the form of powders having a particle size of between 1 and 200 microns. It is seen that in the illustrated example, warp fibers 1310 and weft fibers 1312 and the interstices 1314 therebetween each have formed thereon and therein a pair of opposite-facing impregnation particle layers 1302 whose thickness is uniform to a high degree, having a variation of less than 5% and preferably approximately 1%. Typically each of warp fibers 1310 and weft fibers 1312 is formed of a multiplicity of individual fiber strands 1316. The pre-impregnated material of Fig. 16 is preferably realized by accelerated impingement of a stream of impregnation material particles onto the web material 1300 followed by the application of heat, in accordance with the teachings of applicant/assignee's Published PCT Patent Application WO 03/024609, the disclosure of which is hereby incorporated by reference. As noted above, in the embodiments of Figs. 12 - 16, the impregnation particle layers lie outside of the web material to a somewhat greater degree than in the embodiments of Figs. 7 - 11. In the above-described embodiment of Fig. 16, it is seen that approximately 60% of the thickness of each of the impregnation particle layers 1302 lies outside of the web material, while in Fig. 11, approximately 40% of the impregnation particle layers 502 lies outside the web material. Reference is now made to Fig. 17, which illustrates a laminate formed of a plurality of layers of pre-impregnated material, preferably of the type described above with respect to any of Figs. 7, 11, 12 and 16. This laminate is preferably formed by applying heat and pressure to a plurality of layers of the pre-impregnated material in a mold. As seen in Fig. 17, the application of pressure deforms the warp and weft fibers, here designated by reference numerals 1400 and 1402 respectively, spreading out the individual fiber strands thereof, respectively designated by reference numerals 1410 and 1412. In such a case, the impregnation particle layers of the various layers of pre- impregnated material become fused together, and the fibers of various layers of pre- impregnated material also tend to be merged. It is a particular feature of the present invention that due to the high degree of uniformity of thickness of the impregnation particle layers, voids in the laminate are avoided to a significant extent and highly uniform laminate surfaces are realized. The laminate of Fig. 17 is particularly suitable for use in resin transfer molding (RTM) in which additional impregnation particles are added during the final molding process. Reference is now made to Fig. 18, which illustrates a laminate formed of a plurality of layers of pre-impregnated material, preferably of the type described above with respect to any of Figs. 8, 10, 13 and 15. This laminate is preferably formed by applying heat and pressure to a plurality of layers of the pre-impregnated material in a mold. As seen in Fig. 18, the application of pressure deforms the warp and weft fibers, here designated by reference numerals 1500 and 1502 respectively, spreading out the individual fiber strands thereof, respectively designated by reference numerals 1510 and 1512. In such a case, the impregnation particle layers of the various layers of pre- impregnated material become fused together, and the fibers of various layers of pre- impregnated material also tend to be merged. It is a particular feature of the present invention that due to the high degree of uniformity of thickness of the impregnation particle layers, voids in the laminate are avoided to a significant extent and highly uniform laminate surfaces are realized. The laminate of Fig. 18 is suitable for molding which does not involve the addition of impregnation particles to the laminate. It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of various features described and shown in the foregoing description as well as modifications and variations thereof which would occur to a person of ordinary skill in the art upon reading the foregoing description and which are not in the prior art.

Claims

C L A I M S

1. A method for manufacture of a pre-impregnated product comprising: causing a substrate moving at a linear speed of at least 100 meters per minute to generally horizontally traverse a first coating stage at which impregnation particles are caused to be deposited onto a first surface thereof; thereafter causing said substrate moving at a linear speed of at least 100 meters per minute to generally horizontally traverse a first heated pressing stage at which said impregnation particles are caused to be impregnated into said substrate from said first surface; thereafter causing said substrate moving at a linear speed of at least 100 meters per minute to generally horizontally traverse a second coating stage at which impregnation particles are caused to be deposited onto a second surface thereof; and thereafter causing said substrate moving at a linear speed of at least 100 meters per minute to generally horizontally traverse a second heated pressing stage at which said impregnation particles are caused to be impregnated into said substrate from said second surface.

2. A method for manufacture of a pre-impregnated product according to claim 1 and also comprising the step of reversing the orientation of said substrate between said first heated pressing stage and said second coating stage.

3. A method for manufacture of a pre-impregnated product according to either of claims 1 and 2 and wherein at least one of said first and second coating stages includes coating said substrate with electrostatically charged particles supplied from a plurality of nozzles, each extending at least along the entire width of the substrate.

4. A method for manufacture of a pre-impregnated product according to either of claims 1 and 2 and wherein at least one of said first and second coating stages includes coating said substrate with electrostatically charged particles supplied from a plurality of nozzles, each extending at least along the entire width of the substrate generally perpendicuarly to a direction of movement of said substrate relative thereto.

5. A method for manufacture of a pre-impregnated product according to any of the preceding claims and wherein said impregnation particles comprise particles selected from the group consisting of: a thermoplastic material, a thermosettmg material, an epoxy, a phenolic material, a polyimide, chalk, talk, a ceramic material, a glass material, organic pigments and inorganic pigments.

6. A method for manufacture of a pre-impregnated product according to claim 5 and wherein at least one of said thermoplastic material and said thermosetting material comprises particles selected from the group consisting of: PP, PA, PPS, PEEK, PEKK, PBT, PEI and PAI.

7. A method for manufacture of a pre-impregnated product according to any of the preceding claims and wherein said substrate comprises a material selected from the group consisting of: paper, cardboard, rubber, metal foil, a woven material, a non- woven material, a perforated material, a non-perforated material, a natural material, an organic material, a tow formed of fibers and a yarn formed of fibers.

8. A method for manufacture of a pre-impregnated product according to claim 7 and wherein said metal foil comprises at least one of an aluminum foil and a copper foil.

9. A method for manufacture of a pre-impregnated product according to either of claims 7 and 8 and wherein said fiber comprises a material selected from a group consisting of: carbon fiber, glass fiber and metal fiber.

10. Apparatus for manufacture of a pre-impregnated product comprising: a substrate driver causing a substrate to move horizontally at a linear speed of at least 100 meters per minute; a first coating assembly, traversed by said substrate at a linear speed of at least 100 meters per minute, operative to deposit impregnation particles onto a first surface of said substrate: a first heated pressing assembly, traversed by said substrate at a linear speed of at least 100 meters per minute, operative to impregnate said impregnation particles into said substrate from said first surface; a second coating assembly, traversed by said substrate at a linear speed of at least 100 meters per minute, operative to deposit impregnation particles onto a second surface of said substrate; and a second heated pressing assembly, traversed by said substrate at a linear speed of at least 100 meters per minute, operative to impregnate said impregnation particles into said substrate from said second surface.

11. Apparatus for manufacture of a pre-impregnated product according to claim 10 and also comprising a substrate orientation reverser for reversing the orientation of said substrate between said first heated pressing assembly and said second coating assembly.

12. Apparatus for manufacture of a pre-impregnated product according to either of claims 10 and 11 and wherein at least one of said first and second coating assemblies comprises a plurality of nozzles, each said nozzle extending at least along the entire width of said substrate, and wherein said at least one of said first and second coating assemblies is operative to coat said substrate with electrostatically charged particles supplied from said plurality of nozzles.

13. Apparatus for manufacture of a pre-impregnated product according to either of claims 10 and 11 and wherein at least one of said first and second coating assemblies comprises a plurality of nozzles each extending at least along the entire width of said substrate generally perpendicuarly to a direction of movement of said substrate relative thereto, and wherein said at least, one of said first and second coating assemblies is operative to coat said substrate with electrostatically charged particles supplied from said plurality of nozzles.

14. Apparatus for manufacture of a pre-impregnated product according to any of claims 10 - 13 and wherein said impregnation particles comprise particles selected from the group consisting of: a thermoplastic material, a thermosetting material, an epoxy, a phenolic material, a polyimide, chalk, talk, a ceramic material, a glass material, organic pigments and inorganic pigments.

15. Apparatus for manufacture of a pre-impregnated product according to claim 14 and wherein at least one of said thermoplastic material and said thermosetting material comprises particles selected from the group consisting of: PP, PA, PPS, PEEK, PEKK, PBT, PEI and PAI.

16. Apparatus for manufacture of a pre-impregnated product according to any of claims 11 - 15 and wherein said substrate comprises a material selected from the group consisting of: paper, cardboard, rubber, metal foil, a woven material, a non-woven material, a perforated material, a non-perforated material, a natural material, an organic material, a tow formed of fibers and a yarn formed of fibers.

17. Apparatus for manufacture of a pre-impregnated product according to claim 16 and wherein said metal foil comprises at least one of an aluminum foil and a copper foil.

18. Apparatus for manufacture of a pre-impregnated product according to either of claims 16 and 17 and wherein said fiber comprises a material selected from a group consisting of: carbon fiber, glass fiber and metal fiber.

19. A pre-impregnated material comprising: a textile substrate; and an impregnation particle layer adhered to said textile substrate, said pre-impregnated material being characterized in that said impregnation particle layer has a uniforrnity of thickness having a variation of less than 5% of its average thickness.

20. A pre-impregnated material comprising: a textile substrate; and an impregnation particle layer adhered to said textile substrate, said pre-impregnated material being characterized in that said impregnation particle layer has an impregnation depth of at least 60% of the thickness of said textile substrate.

21. A pre-impregnated material comprising: a textile substrate; and an impregnation particle layer adhered to said textile substrate, said pre-impregnated material being characterized in that said impregnation particle layer has a thickness exceeding 300 microns.

22. A pre-impregnated material comprising: a textile substrate; and an impregnation particle layer adhered to said textile substrate, said pre-impregnated material being characterized in that the weight of said impregnation particle layer is at least 70% of the weight of said pre-impregnated material.

23. A pre-impregnated material comprising: a textile substrate; and an impregnation particle layer adhered to said textile substrate, said pre-impregnated material being characterized in that said impregnation particle layer has a thickness less than 50 microns.

24. A pre-impregnated material comprising: a textile substrate; and an impregnation particle layer adhered to said textile substrate, said pre-impregnated material being characterized in that the weight of said impregnation particle layer is less than 10% of the weight of said pre-impregnated material.

25. A pre-impregnated material according to claim 26 and wherein the weight of said impregnation particle layer is less than 5% of the weight of said pre-impregnated material.

26. A pre-impregnated material comprising: a textile substrate; and an impregnation particle layer adhered to said textile substrate, said pre-impregnated material being characterized in that said impregnation particle layer includes particles having a size spectrum which extends over at least two orders of magnitude.

27. A pre-impregnated material comprising: a textile substrate; and an impregnation particle layer adhered to said textile substrate, said pre-impregnated material being characterized in that said impregnation particle layer includes particles having a density spectrum which extends over at least one order of magnitude.

28. A pre-impregnated material according to any of claims 21 — 27 and wherein said impregnation particle layer has an impregnation depth of at least 60% of the thickness of said textile substrate.

29. A pre-impregnated material according to any of claims 20 - 28 and wherein said impregnation particle layer has an impregnation depth of at least 80% of the thickness of said textile substrate.

30. A pre-impregnated material according to any of claims 20 - 29 and wherein said impregnation particle layer has a uniformity of thickness having a variation of less than 5% of its average thickness.

31. A pre-impregnated material according to any of claims 19 — 30 and wherein said impregnation particle layer has a uniformity of thickness having a variation of less than 2% of its average thickness.

32. A pre-impregnated material according to any of claims 19 - 31 and wherein said impregnation particle layer has a uniformity of thickness having a variation of less than 2% of its average thickness along its width.

33. A pre-impregnated material according to any of claims 19 - 32 and wherein said impregnation particle layer is fully melted.

34. A pre-impregnated material according to any of claims 19 - 32 and wherein said impregnation particle layer is partially melted and partially in particulate form.

35. A pre-impregnated material according to any of claims 19 - 34 and wherein said impregnation particle layer is formed as a plurality of impregnation particle layers.

36. A pre-impregnated material according to any of claims 19 - 35 and wherein different ones of said plurality of impregnation particle layers have different thicknesses.

37. A pre-impregnated material according to any of claims 19 — 36 and wherein different ones of said plurality of impregnation particle layers are formed of different impregnation particle materials.

38. A laminate formed of a plurality of layers of pre-impregnated material, at least one of said plurality of layers of pre-impregnated material comprising: a textile substrate; and an impregnation particle layer adhered to said textile substrate, said pre-impregnated material being characterized in that said impregnation particle layer has a uniformity of thickness having a variation of less than 5% of its average thickness.

39. A laminate formed of a pluraUty of layers of pre-impregnated material, at least one of said plurality of layers of pre-impregnated material comprising: a textile substrate; and an impregnation particle layer adhered to said textile substrate, said pre-impregnated material being characterized in that said impregnation particle layer has a thickness exceeding 300 microns.

40. A laminate formed of a plurality of layers of pre-impregnated material, at least one of said plurality of layers of pre-impregnated material comprising: a textile substrate; and an impregnation particle layer adhered to said textile substrate, said pre-impregnated material being characterized in that the weight of said impregnation particle layer is at least 70% of the weight of said pre-impregnated material.

41. A laminate formed of a plurality of layers of pre-impregnated material, at least one of said plurality of layers of pre-impregnated material comprising: a textile substrate; and an impregnation particle layer adhered to said textile substrate, said pre-impregnated material being characterized in that said impregnation particle layer has a thickness less than 50 microns.

42. A laminate formed of a plurality of layers of pre-impregnated material, at least one of said plurality of layers of pre-impregnated material comprising: a textile substrate; and an impregnation particle layer adhered to said textile substrate, said pre-impregnated material being characterized in that the weight of said impregnation particle layer is less than 10% of the weight of said pre-impregnated material.

43. A laminate formed of a plurality of layers of pre-impregnated material, at least one of said plurality of layers of pre-impregnated material comprising: a textile substrate; and an impregnation particle layer adhered to said textile substrate, said pre-impregnated material being characterized in that said impregnation particle layer includes particles having a size spectrum which extends over at least two orders of magnitude.

44. A laminate formed of a plurality of layers of pre-impregnated material, at least one of said plurality of layers of pre-impregnated material comprising: a textile substrate; and an impregnation particle layer adhered to said textile substrate, said pre-impregnated material being characterized in that said impregnation particle layer includes particles having a density spectrum which extends over at least one order of magnitude.