RU2212381C2 - Fiber glass reinforced prepreg (versions), laminate (versions) - Google Patents

Abstract

FIELD: manufacture of reinforced laminates for printed circuit boards. SUBSTANCE: prepreg for printed circuit board base comprises polymeric material and cloth containing glass fibers and coating compatible with matrix material. Prepreg has drill wear factor not in the excess of 32%, which is determined after drilling of 2,000 holes through pile of tree laminates. Each laminate includes eight prepregs at hole density of 62 holes per square cm and feeding of 0.001 per one revolution, when drill used is made of tungsten carbide and has diameter of 0.46 mm. EFFECT: reduced wear of drill tip, increased precision in arrangement of drilled holes, and increased efficiency of spinning equipment. 56 cl, 8 dwg, 7 tbl, 2 ex

Description

 This patent application is in part a continuation of the US patent application serial No. 09/170578 by B. Novich et al., Entitled "Fiberglass Reinforced Laminates, Electronic Boards, and Fabric Layout Methods", filed October 13, 1998, which in turn is partly continuing the application for US patent serial 09/130270, B. Novich et al., under the name "Fiberglass Reinforced Laminates, Electronic Boards and Fabric Layout Methods", filed Aug. 6, 1998, which is no longer being processed, cat Ora is partly extended by US patent application Serial 09/034525, B. Novich et al. under the name "Strands of glass fibers coated with inorganic lubricant and products comprising them", registered on March 3, 1998, the clerical work of which is currently discontinued. This application is also in part a continuation of the US patent application Serial No. 09/170780, by B. Novich et al., Entitled “Inorganic Lubricant Coated Glass Fiber Strands and Including Products”, filed October 13, 1998, which in turn is partly continuing the US patent application Serial 09/034525, B. Novich et al., entitled "Inorganic Lubricant Coated Glass Fiber Strands and Including Products", filed March 3, 1998, is currently withdrawn. This application is also partly continuing the application for US patent serial 09/170781, B. Novich et al., Under the name "Strands of fiberglass coated with heat-conducting inorganic solid particles, and including these strands of the product", registered October 13, 1998, which in turn, is partly continuing the application for a US patent with serial 09/034663, registered March 3, 1998, currently withdrawn.

 This patent application is related to the US patent application Serial No. 09/170579, B. Novich et al., Entitled "Methods for Decelerating Friction-induced Wear of Fiber Strands", filed October 13, 1998, which is partly continuing US Patent Application Serial 09/034078, registered March 3, 1998, currently withdrawn; U.S. Patent Application Serial No. 09/170566, by B. Novich et al., entitled "Impregnated Strands of Fiberglass and Products Included Therein," registered Oct. 13, 1998, which is partly extending the U.S. patent application serial No. 09/034077 registered March 3, 1998, currently recalled; and U.S. Patent Application Serial No. 09/170565, by B. Novich et al., entitled “Inorganic Particle Coated Glass Fiber Strands and Products Included thereof”, filed Oct. 13, 1998, which in turn partially extends patent application U.S. Serial 09/034056, registered March 3, 1998, is currently recalled.

 This patent application claims the rights to provisional patent application US 60/133075, registered May 7, 1999; 60/133076, registered May 7, 1999, and 60/146337, registered July 30, 1999

 The present invention relates mainly to reinforced laminates for electronic circuit boards, and more particularly, to laminates containing fiberglass woven materials having a coating compatible with the polymeric materials of the laminate matrix and giving the laminate improved characteristics associated with its drilling.

 As a rule, electronic boards are made of laminated layers of polymer-impregnated fabric consisting of reinforcing fibers, such as fiberglass, which give the board dimensional stability, which allows maintaining the integrity of the electronic circuits mounted on it. Holes are made in the laminate by drilling through the layers of the laminate or the base of the board in order to interconnect electronic circuits located on different planes of the laminate. It has been established that the hardness of the fiberglass of the laminate and the heat generated during drilling can accelerate the wear of the cutting edge of the drill. As a result, it will be possible to drill fewer holes with a drill before it is replaced and / or sharpening the cutting edge of the drill, and the overall useful life of the tool is reduced. In addition, it was found that the accelerated wear of the cutting edge of the drill also affects the accuracy of the location of the holes and, in particular, the output end of the holes drilled through the laminate. To reduce the wear effect of drill bits, US Pat. No. 5,593,767 describes, for example, an optical fiber fabric that is impregnated with a thermosetting resin. This laminate can be used in the manufacture of printed circuit boards, with which the wear of drill bits is reduced.

As a rule, the glass fibers of which these reinforced laminating fabrics are composed are coated with a sizing composition during the manufacture of the fibers in order to protect the fibers from abrasion during subsequent manufacturing operations. For example, to protect fibers from abrasion against each other and about equipment during fabrication, sizing compositions based on starch and oil are used that can increase the fragility of the fibers. Organic lubricants, such as alkylimidazoline derivatives and amide substituted polyethyleneimines, are added to the sizing compositions to reduce abrasion. However, such organic lubricants may break down during further processing steps or may lead to undesirable side reactions with other sizing components or with matrix material components. In addition, many commonly used sizing components can adversely affect the adhesion between glass fibers and matrix material, for example starches, which are commonly used as film formers in textile sizing, are generally not compatible with the polymer material of the laminate matrix. In order to prevent incompatibilities between fiberglass and matrix materials, the coating composition or sizing composition is usually removed from the woven fabric prior to lamination by thermal decomposition of the sizing components (which is called heat treatment or degreasing) or by washing the fabric with water or another solution. A typical heat treatment method involves heating the fabric at 380 ^{° C.} for 60-80 hours. The cleaned tissue is then again coated with an organosilicon (silane) sizing to improve adhesion between the glass fiber and the matrix polymer.

 The strength of the glass fibers, more specifically, the laminate's flexural strength, can be significantly reduced by these fabric cleaning operations. Thermal cleaning of high silica glass fibers such as D-glass, S-glass and Q-glass is particularly undesirable due to the loss of strength and discoloration.

 Many compositions for coating glass fibers are described in the art that require heat or water treatment before using glass fibers as reinforcing elements in a composite or laminate. Japanese patent application 9-208268 describes a fabric having filaments obtained from glass fibers coated immediately after spinning with starch or a synthetic polymer, as well as 0.001-20.0 wt.% Particles of inorganic substances such as colloidal silica, calcium carbonate, kaolin and talc. Before manufacturing the laminate, it is necessary to conduct thermal or water degreasing.

 US 5,286,562 describes a textile strand for mesh products that is suitable for weaving on pneumatic weaving machines and which has a coating comprising at least 45% by weight of wax, lubricants, polyvinylpyrrolidone and organosilicon resins. US Pat. No. 5,038,555 describes twisted bundles of fiberglass for mesh products coated with an aqueous chemical composition including an epoxy film former, emulsifier, lubricant, organofunctional metal sizing, polyvinylpyrrolidone, polyethylene and water.

 In order to avoid thermal cleaning of the glass fiber fabric, Japanese Patent Application 8-119682 proposes an agent for primary sizing of glass fibers containing a water-soluble epoxy resin and having a pH of from 5.5 to 7.5, which facilitates the removal of the sizing with water. Similarly, US Pat. No. 5,236,777 describes methods for producing fiberglass for reinforcing a polymer by coating glass fibers with a primary sizing composition comprising at least one water-soluble film former selected from the group consisting of amine-modified epoxy resin, epoxy resin with addition of ethylene oxide and bisphenol A with the addition of ethylene oxide, silicone sizing and lubricant, as well as washing the threads with water to reduce the amount of primary sizing to a value s of less than 0.25 wt.% of the LOI (loss on ignition), and the processing composition for the secondary dressing. Japanese Patent Application 9-268034 describes binder materials for untwisted glass fibers, including a water-soluble urethane compound and / or a water-soluble epoxy product modified by the addition reaction with a polyhydric alcohol.

 US Pat. No. 4,933,381 describes a polymer-compatible sizing composition for glass fibers containing an epoxy film former, a nonionic lubricant, a cationic lubricant, an organosilicon sizing agent, and an acid such as acetic acid or citric acid.

 Japanese patent application 8-325950 describes a sizing for fiberglass, comprising as essential components polyvinylpyrrolidone, a water-soluble epoxy resin with an amine additive and an organosilicon sizing that does not require heat removal from the finished fiberglass.

 Japanese patent application 7-102483 describes a composition for the secondary sizing of warp yarns for fiberglass intended for the manufacture of fiberglass, not requiring thermal degreasing. This warp sizing composition consists mainly of polyvinylpyrrolidone and contains an additive such as high molecular weight polyethylene oxide. A water soluble epoxy resin may be included as a binder component.

 It is desirable to have an inert lubricant for inhibiting the abrasion of glass fibers, which is not noticeably destroyed during technological operations, improves the weldability of the laminate, including glass fiber, and is compatible with polymer matrix materials. However, the use of inorganic materials is mainly focused on fillers to modify the basic physical properties of composites, and not on increasing the resistance of reinforcing fibers to abrasion.

 U.S. Pat. column 4, lines 3-10). One or more layers of board base material, such as fiberglass fabric, may be included in the heat-conducting material.

US Pat. No. 3,312,569 describes the adherence of alumina particles to the surfaces of glass fibers, and Japanese Patent Application 9-208268, as mentioned earlier, describes a fabric having filaments made from glass fibers coated immediately after spinning with starch or a synthetic polymer, as well as inorganic particles such like colloidal silica, calcium carbonate, kaolin and talc, to improve the penetration of the polymer between the reinforcing glass fibers during the manufacture of the composite. However, the Mos hardness values for alumina and silica are higher than about 9 and about 7 ¹ ( ¹ See publications R. Weast (Ed.), Handbook of Chemistry and Physics, CRC Press (1975), page F-22, and H. Katz et al. (Ed.), Handbook of Fillers and Plastics (1987), on page 28, which are incorporated herein by reference.) Respectively, which can lead to abrasion of softer glass fibers.

 US Pat. 1 micrometer. However, limited distribution and environmental considerations make the use of vacuum deposition methods and a plasma process in the conditions of spunbond production of glass fibers impractical.

 USSR patent 859400 describes an impregnating composition for the manufacture of fiberglass laminates, the composition comprising an alcohol solution of a phenol-formaldehyde polymer, graphite, molybdenum disulfide, polyvinyl butyral and a surfactant. Volatile alcohol solvents are undesirable for fiberglass applications.

 US Pat. No. 5,217,778 describes a dry friction liner for couplings comprising a composite fiberglass yarn, metal wire and polyacrylonitrile fibers that are impregnated and coated with heat-curing cement or a binder system. The binder material may include friction particles such as carbon black, graphite, metal oxides, barium sulfate, aluminum silicate, ground rubber particles, ground organic polymers, polymerized cashew nut oil, clay, silica or cryolite (see column 2, lines 55- 56), to modify the frictional characteristics of the composite.

 There is a need for lubricating coatings for fiberglass, compatible with various polymer matrix materials, which would reduce wear on the tip of the drill and increase the accuracy of the location of the drilled holes. In addition, it would be especially desirable that the coating is also compatible with modern pneumatic weaving equipment to increase its productivity.

 One aspect of the present invention is a prepreg (prefabricated) for the base of electronic circuit boards, including: (a) a polymer matrix material; and (b) a fabric comprising a strand consisting of fiberglass, at least a portion of the fabric has a coating compatible with the polymer matrix material, and the prepreg has a percentage of wear on the cutting edge of the drill of not more than 32%, which is determined after 2000 holes are drilled through a stack of 3 laminates, each laminate comprising eight prepregs at a hole density of 62 holes per square centimeter and at a feed rate of 0.001 when using a tungsten carbide drill with a diameter of 0.46 mm. The present invention also relates to a laminate comprising this prepreg.

 Another aspect of the present invention is a prepreg for the base of electronic circuit boards, comprising: (a) a polymer matrix material; and (b) a woven reinforced fabric comprising fiberglass, wherein at least a portion of the fabric has a coating that is compatible with the polymer matrix material, and the prepreg has a deflection distance of the drilled holes of not more than 36 micrometers, determined after 2000 holes are drilled through a stack of 3 laminates with a hole density of 62 holes per square centimeter and when feeding per revolution of 0.001 when using a drill with a diameter of 0.46 mm made of tungsten carbide. The present invention also relates to a laminate comprising this prepreg.

The preceding brief description of the present invention, as well as the following detailed description of preferred embodiments thereof, will be better understood when taken in conjunction with the accompanying drawings. In the drawings:
FIG. 1 is a cross-sectional view of a reinforced laminate in accordance with the present invention;
FIG. 2 is a top view of one embodiment of a fabric incorporating the properties of the present invention;
Figure 3 is a perspective view of a strand of coated fibers in accordance with the present invention;
FIG. 4 is a cross-sectional view of an alternative embodiment of a reinforced laminate in accordance with the present invention;
FIG. 5 is a cross-sectional view of the base of electronic circuit boards in accordance with the present invention;
FIG. 6 is a schematic illustration of a method for producing an opening in a fabric layer of a backing of an electronic board;
FIG. 7 is an end view of a drill showing a primary cutting edge;
Fig is a location diagram of drilled holes.

 The laminates of the present invention are reinforced with a fabric comprising strands of coated fibers, and preferably a woven fabric comprising strands of coated glass fibers, which impart a low thermal expansion coefficient to the laminate, good bending strength, heat resistance, hydrolytic stability, low corrosion resistance and low reactivity in the presence of high humidity, reactive acids and alkalis. The strands of coated fibers are compatible with various polymer matrix materials, which can eliminate the need for heat or water treatment of fiberglass fabric before lamination.

 Another significant advantage of the laminates of the present invention is that they exhibit improved drillability, i.e. reduced wear of the cutting edge of the drill and / or increased accuracy of the location of the drilled holes, especially if the laminate is used as the basis for electronic boards. The term "backbone of electronic circuit boards," as used herein, means a structure that mechanically supports and / or electrically interconnects elements, including, but not limited to, active electronic components, passive electronic components, printed circuit boards, integrated circuits, semiconductor devices and other hardware elements associated with the above elements, including, but not limited to, connectors, sockets, clamps, and heat sinks.

 Another advantage of the laminates of the present invention is that they can be made of glass fibers suitable for use in pneumatic weaving. As used herein, the term "pneumatic weaving" refers to the type of weaving of the web in which the weft thread is inserted into the throat of a weaving machine using a jet of compressed air coming from one or more air jets.

 In FIG. 1, where the same elements denote the same elements, the laminate 10 of the present invention is shown. The laminate 10 includes a matrix polymer material 12 (described in detail below) that is reinforced with a reinforcing fabric 14. The fabric 14 may be a woven or non-woven fabric, such as (but not limited to) a knitted fabric or mat obtained using any suitable method, such as knitting, weaving or making mats. Preferably, the fabric 14 is a woven fabric obtained in the process of pneumatic weaving, well known to specialists in this field of technology. Laminate 10 can also be a laminate with a unidirectional orientation of the fibers, in which most of the fibers, threads and strands in each layer of fabric are oriented in the same direction.

 Typically, a laminate comprises a plurality of prepregs, with each prepreg including fabric 14 and a partially curable polymer matrix 12, which will be described in detail below. The number of prepregs in the laminate can be from one to about 40. In order for the figures to be more clear, only one prepreg is shown in the laminate 10.

 In FIG. 2 and 3 it can be seen that the fabric 14 includes one or more strands 16 of coated fibers. As used herein, the term “strand” means a plurality of individual fibers. The term "fiber" means an individual thread.

 Fiberglass 18 can be obtained from any type of fiber-forming glass compositions known to those skilled in the art, including glass fibers obtained from such fiber-forming glass compositions, such as "E-glass", "A-glass", "C-glass", "D -glass "," Q-glass "," R-glass "," 3-glass "and derivatives of E-glass. As used herein, the term “fiber-forming” means a material from which a continuous filament, fiber, strand or thread can be formed. The term "E-glass derivatives" as used herein refers to compositions comprising small amounts of fluorine and / or boron, and preferably not containing fluorine and / or boron. In addition, in this description, the expression "small amounts" means an amount of less than about 1 wt.% Fluorine and less than about 5 wt.% Boron. Examples of other fiber-forming glass materials suitable for use in the present invention are basalt and mineral wool. Preferred glass fibers are obtained from E-glass and from derivatives of E-glass. Such compositions are well known to those skilled in the art, and further discussion in the present description is not necessary. The glass fibers of the present invention can be obtained by any suitable method known in the art for glass fibers. For example, glass fibers can be obtained by molding fibers directly from molten glass or by molding from molten glass beads. In the case of the operation of forming fibers directly from the glass, the raw materials are combined, melted and homogenized in a glass melting furnace. The molten glass moves from the furnace to the piggy bank and to the fiber production devices, where they are converted into continuous glass fibers. In the operation of forming fibers from molten glass balls, pieces of glass or glass balls having the desired finished glass composition are preformed and fed to dies, where they are melted and converted into continuous glass fibers. If pre-boiling is used, then the glass beads are first fed to the pre-boiling device, melted, then the molten glass is fed to the fiber producing device, where the glass is converted into continuous fibers. In the present invention, glass fibers are preferably obtained by molding directly from molten glass. See K.Loewenstein, The Manufacturing Technology of Glass Fibers (3d Ed. 1993), pages 30-44, 47-60, 115-122, and 126-135, U.S. Patents 4,542,106 for more information on glass compositions and methods for making glass fibers. and 5,789,329, as well as in the IPC-EG-140 Specification for Finished Fabric Woven from 'E' Glass for Printed Boards ", The Institute for Interconnecting and Packaging Electronic Circuits (June 1997), which are included in this description. as links.

 Glass fibers may have a nominal filament diameter of from about 3.0 to about 35.0 micrometers (in accordance with the types of filaments indicated by letters B to U and above), and preferably they have a nominal filament diameter of from about 5.0 to about 30.0 micrometers. For fine thread applications, the average nominal filament diameter is preferably from about 5 to about 7 micrometers. The number of fibers per strand can be from about 2 to about 15000, and preferably from about 100 to about 7000. For more information on the nominal diameters of the filaments, as well as the designations of glass fibers, see the Loewenstein publication on pages 25 and 27, which is included in the present description by reference.

In addition to fiberglass, the coated strand 16 may also include fibers 20 obtained from other fiber-forming inorganic materials, fiber-forming organic materials, and also mixtures and combinations thereof. Inorganic and organic materials can be of either artificial or natural origin. Those skilled in the art will recognize that fiber-forming inorganic and organic materials can also be polymeric materials. As used herein, the term "polymeric materials" refers to a material represented by macromolecules consisting of long chains of atoms bonded together that can intertwine in solution or in solid state ² ( ² James Mark et al., Inorganic Polymers, Prentice Hall Polymer Science and Engineering Series, (1992), on page 1, is incorporated herein by reference.).

 Non-limiting examples of suitable non-glass fiber-forming inorganic materials include ceramic materials such as silicon carbide, carbon, graphite, mullite, alumina, and piezoelectric ceramic materials. Non-limiting examples of suitable organic fiber-forming materials include cotton, cellulose, natural rubber, linen, ramie, hemp, sisal and wool. Non-limiting examples of suitable organic polymeric fiber-forming materials include materials derived from polyamides (such as nylon and aramids), thermoplastic polyesters (such as polyethylene terephthalate and polybutylene terephthalate), acrylics (such as polyacrylonitriles), polyolefins, polyurethanes and vinyl polymers (such like polyvinyl alcohol). Non-glass fiber-forming materials suitable for use in the present invention, as well as methods for the preparation and processing of such fibers, are described in detail in Encyclopedia of Polymer Science and Technology by Vol. 6 (1967) on pages 505-712, which is incorporated herein by reference. It is understood that mixtures or copolymers of any of the above materials and combinations of fibers obtained from any of the above materials can also be used for the present invention, if desired.

 The present invention will now be described mainly in the context of fiberglass strands, although it will be understood by those skilled in the art that strand 16 may further include one or more non-glazed fibers described above.

 Although this does not limit the scope of the present invention, in the embodiment of the fabric 14 shown in FIG. 2, at least one, and preferably all fibers 18 of the strand 16 are coated with a layer 22 of a coating composition applied to at least a portion of the surface of the fibers 18 for protection fiber surfaces from abrasion during technological operations and to reduce fiber breakdowns. Preferably, the coating composition is applied to the entire outer surface or to the periphery of each of the fibers 18 of the strand 16, as shown in FIG.

 The coating compositions of the present invention are present on the fibers as a primary sizing composition (which is preferred), a secondary coating composition applied to the sizing composition and / or as a tertiary or external coating, as desired. In this application, the terms “sizing”, “sizing” or “sizing” refer to a coating composition applied to the fibers immediately after they are received. In an alternative embodiment, the terms “sizing”, “sizing” or “sizing” further refer to a coating composition (also known as “finishing sizing”) that is applied to the fibers after at least part of the composition, and typically all conventional primary coating composition is removed by heat treatment, water treatment or chemical treatment, i.e. to the finishing dressing, which is applied to uncoated glass fibers included in the fabric. The term "secondary coating" refers to a coating composition that is applied a second time to one or a plurality of strands after application of the sizing composition, and preferably after it is at least partially dried. This coating can be applied to the fibers before the fibers are incorporated into the fabric, or after incorporation of the fibers into the fabric, i.e. by coating the fabric.

 The coating compositions used in the present invention are preferably aqueous coating compositions. Although not preferred for safety reasons, coating compositions may also contain volatile organic solvents such as alcohol or acetone, if necessary, but preferably they do not contain such solvents.

 The coating composition used in the present invention includes one or more polymeric materials, such as thermosetting materials or thermoplastic materials, which are compatible with the polymeric material 12 of the matrix of the laminate 10, i.e. the components of the coating composition improve the wet and wet properties of the matrix material on the strands of fibers and provide the necessary physical properties of the composite. Preferably, the polymeric materials form a substantially continuous film after applying them to the surface of the fibers 18. The polymeric materials may be water soluble, emulsifiable, dispersible and / or curable. In the present description, the phrase "compatible with polymeric matrix materials" means that the components of the coating composition applied to glass fibers improve the wettability and wettability of the matrix material on the fiber strands, provide the necessary physical properties of the composite, are chemically compatible with the polymer matrix material, provide good hydrolytic stability i.e., resistance to movement of water along the interface between the fiber surface and the matrix material, and also means that coating components (or selected coating components) do not need to be removed before incorporation of coated fibers into the polymer matrix material. A measure of the penetration of the polymer matrix material through a mat or fabric is called “wetness”. A measure of the fluidity of the polymer matrix material through glass fiber strands to obtain substantially completely enveloping the entire surface of each glass fiber with the polymer matrix material is called “impregnation”.

 In one embodiment of the invention, the coating composition applied to the fibers 18 included in the laminate 10 includes one or more polymer film-forming materials compatible with thermosetting matrix materials, such as those used to produce laminates for printed circuit boards or circuit boards (hereinafter individually or collectively referred to as "electronic circuit boards"), for example with epoxy resins FR-4, which are multifunctional epoxies, and in one particular embodiment ticipate invention uses difunctional brominated epoxy resins, and polyimides. See publication 1 Electronics Materials Handbook, ASM International (1989) on pages 534-537, which is incorporated herein by reference.

Non-limiting examples of suitable polymeric film-forming materials include thermoplastic polymeric materials such as thermoplastic polyesters, vinyl polymers, polyolefins, polyamides (e.g., aliphatic polyamides or aromatic polyamides such as aramid), thermoplastic polyurethanes, acrylic polymers and mixtures thereof, compatible with thermosetting matrix material. Non-limiting examples of thermoplastic polyesters include DESMOPHEN 2000 and DESMOPHEN 2001KS, both of which are manufactured by Wauer from Pittsburgh, PA, the polyester polymer RD-847A manufactured by Borden Chemicals from Columbus, Ohio, and the DYNAKOLL SI 100 polymer manufactured by Eka Chemicals AB, Sweden. Suitable polyamides include VERSAMID products manufactured by General Mills Chemicals, Inc. Suitable thermoplastic polyurethanes include WITCOBOND ^® W-290H, manufactured by Witco Chemical Corp., Chicago, Illinois, and polyurethane latex RUCOTHANE ^® 2011L, manufactured by Ruco Polymer Corp., of Hicksville, New York.

 Non-limiting examples of suitable thermosetting polymeric materials include thermosetting polyesters, epoxies, vinyl esters, phenolic resins, aminos, thermosetting polyurethanes, and mixtures thereof that are compatible with the thermosetting matrix material. Suitable thermosetting polyesters may include STYPOL polyesters manufactured by Cook Composites and Polymers from Port Washington, Wisconsin, and NEOXIL polyesters manufactured by DSM B.V. from Como, Italy.

Epoxy materials suitable for the present invention contain in their molecule at least one epoxy or oxirane group, such as polyglycidyl ethers of polyhydric alcohols or thiols. Examples of suitable epoxy polymers include epoxy resins EPON ^® 826 EPON ^® 880 and which are epoxy functional polyglycidyl ethers of bisphenol A, manufactured by Shell Chemical Company, of Houston's, Texas. In one embodiment of the coating composition, this coating composition is substantially free of epoxy materials, i.e. contains less than about 5 wt. % epoxy materials, and more preferably less than about 2 wt.%.

 In one non-limiting embodiment of the coating composition, the coating composition includes one or more polyesters (e.g., DESMOPHEN 2000 and RD-847A) and one or more additional film-forming polymers selected from the group consisting of vinylpyrrolidone polymers (which is preferred) polymers of vinyl alcohol and / or starches. Vinyl pyrrolidone polymers suitable for the present invention include polyvinyl pyrrolidones such as PVP K-15, PVP K-30, PVP K-60 and PVP K-90, all of which are available from ISP Chemicals from Wayne, New Jersey. Other suitable vinyl polymers include Resin 2828 and Resin 1037 vinyl acetate emulsion copolymers manufactured by National Starch and Chemical from Bridgewater, New Jersey. Suitable starches include starches derived from potato, corn, wheat, waxy corn, sago, rice, sorghum, and mixtures thereof, such as KOLLOTEX 1250 (low viscosity and low amylose potato starch etherified with ethylene oxide) manufactured by AVEBE from The Netherlands. The amount of additional polymer is preferably less than about 20 wt.%, And more preferably from about 0.1 to about 5 wt.%. Preferably, the coating composition is substantially free of starch, i.e., contains less than about 5% by weight of starch, and more preferably does not contain starch, which is often incompatible with the matrix material.

 The coating composition may include a mixture of one or more thermosetting polymeric materials with one or more thermoplastic polymeric materials. In one embodiment of the invention for electronic circuit board laminates, the polymer materials of the coating composition include a mixture of polyester polymer RD-847A or polymer DYNAKOLL SI 100, polyvinylpyrrolidone PVP K-30, polyester DESMOPHEN 2000 and polyamide VERSAMID. In an alternative embodiment of the invention suitable for laminates for the manufacture of printed circuit boards, the polymeric materials of the aqueous sizing composition include polyvinylpyrrolidone PVP K-30, optionally together with EPON 826 epoxy.

 Typically, the amount of polymer material may be from about 1 to about 90 wt.% Of the coating composition based on the total weight of solids, preferably from about 1 to about 80 wt.%.

-O-N-CR⁵
и моногидроксильный и/или С₂-С₃-циклический остаток 1,2- или 1,3-гликоля, где R¹ представляет собой C₁-С₃-алкил; R² представляет собой Н или С₁-С₄-алкил; R³ и R⁴ независимо выбирают из Н, С₁-С₄-алкила или С₆-С₈-арила; и R⁵ представляет собой С₄-С₇-алкилен. Примеры подходящих совмещающихся или функциональных групп включают эпоксильную, глицидоксильную группы, меркаптогруппу, цианогруппу, аллильную и алкильную группы, уретаногруппу, галогеновую группу, изоцианатогруппу, уреидогруппу, имидазолинильную и винильную группы, акрилатогруппу, метакрилатогруппу, аминогруппу или полиаминогруппу.In addition to, or instead of, the polymeric film-forming materials described above, the coating composition preferably includes one or more resins, such as organosilicon resins, transition metal resins, phosphonate resins, aluminum resins, Werner amino resins, and mixtures thereof. These sizing usually have a dual function. Each metal or silicon atom has one or more groups attached to it, which can either react with the surface of the fiber and / or components of the polymer matrix, or combine with them. The term “combine” as used in the present description means that the groups are chemically attracted to the surface of the fiber and / or to the components of the coating composition, for example, under the influence of polar forces, wetting forces or solvation forces. In one non-limiting embodiment, each metal or silicon atom has one or more hydrolyzable groups attached to it, which allows the sizing to react with the surface of the glass fibers, as well as one or more functional groups, which allows the sizing to react with the components of the polymer matrix . Examples of hydrolyzable groups include:
-OR ¹

-ON-CR ⁵
and a monohydroxy and / or C ₂ -C ₃ cyclic residue of 1,2- or 1,3-glycol, wherein R ¹ is C ₁ -C ₃ -alkyl; R ² represents H or C ₁ -C ₄ alkyl; R ³ and R ^{4 are} independently selected from H, C ₁ -C ₄ alkyl or C ₆ -C ₈ aryl; and R ⁵ is C ₄ -C ₇ alkylene. Examples of suitable combining or functional groups include an epoxy, glycidoxyl group, mercapto group, cyano group, allyl and alkyl groups, urethane group, halogen group, isocyanato group, ureido group, imidazolinyl group and vinyl group, acrylate group, methacrylamino group.

 Functional silicone resins are preferred for use in the present invention. Examples of suitable functional silicone resins include gamma-aminopropyltrialkoxysilanes, gamma-isocyanatopropyltriethoxysilanes, vinyltrialkoxysilanes, glycidoxypropyltrialkoxysilanes and ureidopropyltrialkoxysilanes. Preferred functional silicone resins include gamma-glycidoxypropyltrimethoxysilane A-187, gamma-methacryloxypropyltrimethoxysilane A-174, gamma-aminopropyltriethoxysilane A-1100, aminosilane A-1108, and gamma-ureidopropyltriethoxysilane from OS 60, Tarrytown, New York). The organosilicon sizing can be at least partially hydrolyzed with water before applying it to the fibers, preferably in a stoichiometric ratio of about 1: 1, or, if desired, it can be applied in non-hydrolyzed form. If desired, the pH of the water can be changed by adding an acid or base to initiate or accelerate the hydrolysis of the sizing, which is well known in the art.

 Suitable transition metal based finishes include titanium, zirconium, yttrium and chromium finishes. Suitable titanate and zirconate resins are manufactured by Kenrich Petrochemical Company. Suitable chromium complexes are manufactured by E.I. duPont de Nemours, from Willington, Delaware. Amino-containing resins of the type of Werner resins are complex compounds in which a trivalent atom, such as a chromium atom, is coordinated with an organic acid having an amino-functional group. Other metal chelates and coordination type resins known to those skilled in the art can also be used for this invention.

 The amount of sizing can be from about 1 to about 30 wt.% Based on the total dry weight of the coating composition and preferably from about 1 to about 10 wt.%.

 Although this does not limit the scope of the present invention, in one embodiment of the coating composition shown in FIG. 3, the coating composition of the present invention includes one or more particles 24 that, when applied to at least one fiber 18 of the strand 16, adhere to the outer surface of the fiber 18 and provide the formation of one or more voids 30 between adjacent glass fibers 26, 28 of the strand 16. These voids 30 correspond, as a rule, to the average size 32 of particles 24 located between adjacent fibers.

Particles 24 of the coating composition are preferably discrete particles. In the present description, the term "discrete" means that the particles do not show a tendency to merge or merge with the formation of films under the conditions of technological operations, but instead, as a rule, they retain their individual shape. In addition, the particles preferably have a stable size. In the present description, the term "particles of stable size" means that the particles, as a rule, retain their average size and shape under the conditions of technological operations, for example, when exposed to forces arising between adjacent
fibers during weaving, spinning and other technological operations, which allows you to maintain the desired dimensions of the voids between adjacent fibers 26, 28. In other words, the particles are preferably not crushed, not dissolved and essentially not deformed in the coating composition, i.e. no particles are formed whose maximum size is smaller than the selected average particle size under ordinary conditions of glass fiber processing, such as exposure at temperatures reaching about 25 ^° C, and preferably up to about 100 ^° C and even more preferably up to about 140 ^° C In addition, the particles 24 should not significantly increase in size or expand under the conditions of technological processing of fiberglass, and in particular, in the conditions of technological processing of the composite, when the processing temperature may exceed 1 50 ^o C. In the present description, the phrase "should not significantly increase in size" in relation to the particles means that the particles should not expand or increase in size by more than about 3 times compared with their original size during the process. Preferably, the coating compositions of the present invention are substantially free of heat expanding hollow particles. As used herein, the term “heat expanding hollow particles” refers to hollow particles filled with or containing a foaming agent that, at temperatures sufficient to convert the foaming agent into a volatile form, expand or substantially increase in size. Used herein, the term "essentially do not contain" means that the sizing composition contains less than 20 wt.% Expandable in heat of the hollow particles based on the total mass of solids, more preferably less than about 5 wt. % and most preferably less than 0001 wt.%. In addition, in the present description, the term "stable size" includes both crystalline and non-crystalline materials.

In addition, although this is not necessary, it is preferable that the particles 24 are non-wax. The term "non-wax" means that the materials from which the particles are obtained are not wax-like. As used herein, the term “wax-like” means materials consisting primarily of hydrocarbons with unbranched hydrocarbon chains, with an average chain length of from about 25 to about 100 carbon atoms ^3.4 ( ³ LHSperling. Introduction of Physical Polymer Science, John Wiley and Sons, Inc. (1986), pages 2-5, incorporated herein by reference; ⁴ W. Pushaw et al. "Use of Micronized Waxes and Wax Dispersions in Waterborne Systems", Polymers, Paint, Colors Journal, V.189 , No.4412, January 1999, pages 18-21, incorporated herein by reference.).

 Preferably, particles 24 of the coating composition are discrete, stable in size, non-wax particles. In a specific non-limiting embodiment, the average size of 32 particles 24 is at least about 0.1 micrometers, preferably at least about 0.5 micrometers, and is in the range from about 0.1 to about 5 micrometers, preferably from about 0.5 to about 3.0 micrometers. In one embodiment, particles 24 have a size of at least about 1 micrometer, and preferably from about 1 to about 3 micrometers. In this non-limiting embodiment of the invention, particles 24 have an average size of 32, which is generally smaller than the average diameter of the fibers 18 on which the coating composition is applied. It was found that in twisted yarn made from strands of 16 fibers having a layer 22 of the remainder of the composition for primary sizing, including particles 24 with an average particle size of 32 above, there are sufficient distances between adjacent fibers 26, 28, making it suitable for weaving on a pneumatic loom (ie for pneumatic movement through a loom), while maintaining the integrity of the strand of 16 fibers and ensuring acceptable characteristics of "wet" and "impregnation" during the polymer impregnation The black material of the matrix.

 In another specific non-limiting embodiment, the average size of 32 particles 24 is at least 3 micrometers, preferably at least about 5 micrometers, and is in the range of from about 3 to about 1000 micrometers, preferably from about 5 to about 1000 micrometers and more preferably from about 10 to about 25 micrometers. Preferably, each of the particles 24 has a minimum size of at least 3 micrometers, and more preferably at least about 5 micrometers. In this embodiment of the invention, it is also preferable that the average particle size 32 of particles 24 basically corresponds to the average nominal diameter of the glass fibers. It has been established that fabric made from strands coated with particles of the above sizes shows good “wet” and “wet” characteristics during impregnation with the matrix polymer material.

 Those skilled in the art will understand that mixtures of one or more particles 24 having different particle sizes 32 can be included in the sizing composition in accordance with the present invention to impart desired properties and processing characteristics to strands 16 of fibers and articles subsequently made from them. More specifically, particles of different sizes can be combined in the required quantities so as to obtain fibers having good suitability for pneumatic movement through a weaving machine, as well as a fabric having good impregnation and wetting characteristics.

 Although this does not limit the scope of the present invention, the configuration and shape of the particles 24 can generally be spherical (such as balls, microspheres, or solid hollow spheres), cubic, plate or needle (elongated or filamentous), as desired. In addition, particles 24 may have a hollow, porous, or void-free internal structure. In addition, particles 24 may have a combination of these structures, for example a hollow center with porous or solid walls. For more information on suitable particle characteristics, see H. Katz et al. (Ed.), Handbook of Fillers and Plastics (1987) on pages 9-10, which is incorporated herein by reference.

 Glass fibers undergo abrasion when they come into contact with the rough surfaces of adjacent glass fibers and / or other solid objects or materials with which the glass fibers come into contact during their preparation and subsequent technological operations, such as weaving or spinning. The term "abrasive (caused by friction) wear", as used in the present description, means scraping or cutting pieces of the surface of the fiberglass or breakage of the glass fibers due to friction in contact with particles, edges of objects or objects made of materials that are hard enough to damage fiberglass. See K. Ludema, Friction, Wear, Lubrication (1996), page 129, which is incorporated herein by reference. Abrasive wear of fiberglass strands leads to breakage of the strands during technological operations and to the formation of surface defects in products, such as woven fabrics and composites, which increases the cost and manufacturing cost.

 To minimize abrasive wear, particles 24 have a hardness value not exceeding, i.e. equal to or less than the hardness value of fiberglass (fiberglass). The hardness values of particles and glass fibers can be determined by any conventional hardness measurement method, such as Vickers or Brinell hardness, but are preferably determined according to the original Mos hardness scale, which shows the relative resistance to scratches on the surface of the material. The Mohs values of glass fibers are typically in the range of about 4.5 to about 6.5, and are preferably about 6. See publication R. Weast (Ed.), Handbook of Chemistry and Physics, CRC Press (1975) , on page F-22, which is incorporated herein by reference. The Mos hardness values of the particles suitable for use in the coating composition described above are preferably in the range of about 0.5 to about 6. The Mos hardness values of a few non-limiting examples of particles suitable for use in the present invention are given in table A below.

 As mentioned above, the Mos hardness scale refers to the resistance of the material to scratches. Therefore, the present invention also contemplates particles whose surface has a hardness whose values differ from the hardness of the internal, i.e. below the surface, parts of these particles. More specifically, the surface of the particle can be modified by any of the methods well known in the art, including, but not limited to the chemical modification of its surface characteristics using methods known in the art so that the hardness of the surface of the particle is not higher than the hardness of the glass fibers, and the hardness of the part of the particle below the surface was higher than the hardness of the glass fibers. Alternatively, the particle may be coated or it may be clad or encapsulated to form a composite particle (as described above) having a softer surface.

Typically, particles 24 suitable for use in this invention can be obtained from materials selected from the group consisting of polymer and non-polymer inorganic materials, polymer and non-polymer organic materials, composite materials and mixtures thereof. As used herein, the term “polymeric inorganic material” means a polymeric material having a main chain repeat element based on an element or elements other than carbon. See JE Mark et al. For more information. , on page 5, incorporated herein by reference. Organic polymeric materials include synthetic polymeric materials, semi-synthetic polymeric materials and natural polymeric materials. The term "organic material" in the present description refers to all carbon compounds, except for binary compounds such as carbon oxides, carbides, carbon disulfide, etc .; such ternary compounds as metal cyanides, metal carbonyls, phosgene, carbonyl sulfide and others; and metal carbonates such as calcium carbonate and sodium carbonate. See the publication of R. Lewis, Sr., Hawley's Condensed Chemical Dictionary, (12 ^th Ed. 1993) on pages 761-762, which is incorporated herein by reference. In most cases, organic materials include carbon-containing compounds in which carbon is usually attached to itself and to hydrogen, and often also to other elements, with the exception of carbon-containing ionic compounds. See M. Silberberg, Chemistry, The Molecular Nature of Matter and Change (1996) on page 586, which is incorporated herein by reference. The term "inorganic material", as a rule, means all materials that are not carbon compounds, with the exception of carbon oxides and carbon disulfide. See R. Lewis, Sr., Hawley's Condensed Chemical Dictionary (12 ^tn Ed. 1993) on page 636, which is incorporated herein by reference. Used in this description, the term "inorganic materials" means any materials that are not organic materials. As used herein, the term “composite material” means a combination of one or more different materials. For more information on the particles useful for this invention, see G. Wypych, Handbook of Fillers, 2 ^nd Ed. (1999), pages 15-202, which is incorporated herein by reference.

 Non-polymeric inorganic materials suitable for producing particles 24 include ceramic materials and metallic materials. Suitable ceramic materials include metal nitrides, metal oxides, metal carbides, metal sulfides, metal borides, metal silicates, metal carbonates and mixtures thereof.

 A non-limiting example of a suitable metal nitride is boron nitride, which is the preferred inorganic material from which the particles used in the present invention are obtained. A non-limiting example of a suitable metal oxide is zinc oxide. Suitable metal sulfides include molybdenum disulfide, tantalum disulfide, tungsten disulfide, and zinc sulfide. Suitable metal silicates include aluminosilicates and magnesium silicates such as vermiculite. Suitable metallic materials include graphite, molybdenum, platinum, palladium, nickel, aluminum, copper, gold, iron, silver, and mixtures thereof.

Although not necessary, it is preferable that the particles 24 are also solid lubricants. Used in the present description, the term "solid lubricant" means any solid substance placed between two surfaces to protect them from damage during relative movement and / or to reduce friction and wear. More preferably, particles 24 are inorganic solid lubricants. Used in the present description, the term "inorganic solid lubricant" means that inorganic particles 24 have a characteristic crystallization form, as a result of which they turn into thin flat plates that easily glide on each other's surface, resulting in the effect of antifriction lubrication between the surface of the glass fiber and an adjacent solid surface, at least one of these elements being in motion. See publication R. Lewis, Sr. , Hawley's Condensed Chemical Dictionary (12 ^th Ed. 1993) on page 712, which is incorporated herein by reference. Friction is the sliding resistance of one solid substance to another. See F. Claus, Solid Lubricants and Self-Lubricating Solids (1972) on page 1, which is incorporated herein by reference.

 In one specific embodiment of the present invention, the particles of solid lubricants have a layered structure, which is believed to contribute to reduced tool wear when drilling holes through laminates, which will be described in more detail below. Particles having a layered structure consist of layers of atoms arranged in the form of hexagons, with strong bonds inside this layer and weak van der Waals bonds between the layers, as a result of which there is a low shear force between these layers. A non-limiting example of a layered structure is a hexagonal crystal structure. See Friction, Wear, Lubrication (1996) on page 125, Solid Lubricants and Self-Lubricating Solids on pages 19-22, 42-54, 75-77, 80-81, 82, 90-102, 113-120 and 128, and W. Campbell "Solid Lubricants", Boundary Lubrication; An Appraisal of World Literature, ASME Research Committee on Lubrication (1969) on pages 202-203, which are incorporated herein by reference. Inorganic solid particles having a layered felt structure are also suitable for the present invention.

 Non-limiting examples of suitable layered inorganic solid lubricant particles include boron nitride, graphite, metal dichalcogenides, mica, talc, gypsum, kaolinite, calcite, cadmium iodide, silver sulfide, and mixtures thereof. Preferred particles derived from inorganic solid lubricants include boron nitride, graphite, metal dichalcogenides and mixtures thereof. Suitable metal dichalcogenides include molybdenum disulphide, molybdenum disulide, tantalum disulphide, tantalum disulide, tungsten disulphide, tungsten diselide and mixtures thereof.

 A non-limiting example of an inorganic solid lubricant suitable for use in the coating compositions of the present invention having a hexagonal crystal structure is boron nitride. Particles derived from boron nitride, zinc sulfide and montmorillonite also provide good whiteness of composites with polymer matrix materials, such as nylon 6,6.

Non-limiting examples of boron nitride particles suitable for use in the present invention are boron nitride powder particles of PolarTherm ^® 100 Series (PT 120, PT 140, PT 160 and PT 180), 300 Series (PT 350), and 600 Series (PT 620, PT 630, PT 640 and PT 670) manufactured by Advanced Ceramics Corporation of Lakewood, Ohio. See the publication "PolarTherm ^® Thermally Conductive Fillers for Polymeric Materials", a technical bulletin from Advanced Ceramics Corporation of Lakewood, Ohio (1996), which is incorporated herein by reference. These particles have a thermal conductivity of about 250-300 watts per meter K at 25 ^{° C.} , a dielectric constant of about 3.9, and a volume resistivity of about 10 ¹⁵ ohm-centimeters. The 100 Series powder particles have an average size of from about 5 to about 14 micrometers, the 300 Series powder particles have an average size of about 100 to about 150 micrometers, and the 600 Series powder particles have an average size of about 16 to over 200 micrometers.

 Particles 24 can be obtained from non-polymer organic materials. Examples of non-polymeric organic materials suitable for the present invention include, but are not limited to, stearates (such as zinc stearate and aluminum stearate), carbon black, and stearamide.

Particles 24 can be obtained from inorganic polymeric materials. Non-limiting examples of inorganic polymeric materials include polyphosphazenes, polysilanes, polysiloxane, polygermans, polymer sulfur, polymer selenium, silicones, and mixtures thereof. A specific non-limiting example of particles derived from an inorganic polymer material suitable for use in the present invention is Tospearl ²³ ( ²³ See RJ Perry "Appliccations for Cross-Linked Siloxane Particles", Chemtech, February 1999, pages 39-44 .), which is particles derived from crosslinked siloxanes, and is manufactured by Toshiba Silicones Company, Ltd., from Japan.

 Suitable synthetic organic polymeric materials from which the particles can be obtained include, but are not limited to, thermoset materials and thermoplastic materials. Suitable thermosetting materials include thermosetting polyesters, vinyl esters, epoxies, phenolic plastics, aminos, thermosetting polyurethanes, and mixtures thereof. A specific non-limiting example of a preferred synthetic polymer particle obtained from an epoxy material is an epoxy microgel particle.

Suitable thermoplastic materials include thermoplastic polyesters, polycarbonates, polyolefins, acrylic polymers, polyamides, thermoplastic polyurethanes, vinyl polymers, and mixtures thereof. Preferred thermoplastic polyesters include, but are not limited to, polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Preferred polyolefins include, but are not limited to, polyethylene, polypropylene, and polyisobutylene. Preferred acrylic polymers include styrene-acrylic copolymers and polymers containing methacrylate. Non-limiting examples of synthetic polymer particles obtained from an acrylic copolymer are ROPAQUE ^® HP-1055 ²⁴ ( ²⁴ See Product Description Sheet, entitled "ROPAQUE ^® HP-1055, Hollow Sphere Pigment for Paper and Paperboard Coatings" , October 1994, from Rohm and Haas Company, Philadelphia, PA, on page 1, incorporated by reference.), Which is an opaque, non-film forming, styrene acrylic polymer synthetic pigment with a particle size of 1.0 micrometers, s solids content of 26.5 wt.% and with a volume of voids 55%, ROPAQUE ^® OP-96 ²⁵ ( ²⁵ See the technical bulletin describing the product entitled: "Architectural Coatings - ROPAQUE ^® OP-96, The All Purpose Pigment", April 1997, from Rohm and Haas Company, Philadelphia, on page 1, incorporated herein by reference.), Which is a dispersion of an opaque, non-film forming, styrene acrylic polymer synthetic pigment with a particle size of 0.55 micrometers and a solids content of 30.5 wt.%, And ROPAQUE ^® OP -62-LO ²⁶ ( ²⁶ Ibid.), Also a dispersion of an opaque, non-film forming, styrene acrylic polymer syn tetetic pigment with a particle size of 0.40 micrometers and with a solids content of about 36.5 wt. %, each of which is manufactured by Rohm and Haas Company, from Philadelphia, PA.

 Suitable semi-synthetic organic polymeric materials from which particles 24 can be obtained include, but are not limited to, cellulosic materials such as methyl cellulose and cellulose acetate, and modified starches such as acetate starch ether and ethoxylated starch esters.

 Suitable natural polymeric materials from which particles 24 can be obtained include, but are not limited to, polysaccharides such as starch; polypeptides such as casein; and natural hydrocarbons such as natural rubber and gutta-percha.

In one embodiment of the present invention, polymer particles 18 are made from hydrophobic polymer materials to reduce or limit moisture absorption by coated strands. Non-limiting examples of hydrophobic polymeric materials that are considered suitable for use in the present invention include, but are not limited to, polyethylene, polypropylene, polystyrene, and polymethyl methacrylate. Not limiting examples of polystyrene copolymers include pigments ROPAQUE ^® HP-1055, ROPAQUE ^® OP-96 and ROPAQUE ^® PR-62-LO (each of which is described above).

In another embodiment of the present invention, the polymer particles 18 are obtained from polymeric materials having a glass transition temperature (T _g ) and / or a melting point higher than about 25 ^{° C.} , and preferably higher than about 50 ^° C.

 Composite particles 24 suitable for use in the present invention include particles obtained by cladding, encapsulating, or coating particles derived from a primary material with one or more secondary materials. For example, an inorganic particle made from an inorganic material, such as silicon carbide or aluminum nitride, can be coated with silica, carbonate or nanoclay to obtain a suitable composite particle. In another example, it is possible to react an organosilicon sizing having alkyl side chains with the surface of an inorganic particle derived from an inorganic oxide to produce a suitable composite particle having a softer surface. Other examples include cladding, encapsulating, or coating particles derived from organic or polymeric materials with inorganic materials or various organic or polymeric materials. A specific example of such non-limiting composite particles is DUALITE, a synthetic calcium carbonate coated polymer particle manufactured by Pierce and Sevens Corporation of Buffalo, New York.

In yet another embodiment of the present invention, the particles 24 may be hollow particles obtained from materials selected from the group consisting of inorganic materials, organic materials, polymeric materials, composite materials, and mixtures thereof. Non-limiting examples of materials from which hollow particles can be obtained are described above. Non-limiting examples of the scope of the present invention, hollow polymer particles suitable for use in the present invention include pigments ROPAQUE ^® HP-1055, ROPAQUE ^® OP-96 and ROPAQUE ^® PR-62-LO (each of which is described above). Other non-limiting examples of polymer hollow particles that may be useful for use in the present invention, see H. Katz et al. (Ed.) (1987) on pages 437-452, which is incorporated herein by reference.

Particles 24 of solid lubricant may be present in the form of a dispersion, suspension or emulsion in water. Other solvents, such as mineral oil or alcohol (preferably in an amount of less than 5 wt.%), Can also be included in the sizing composition, if desired. A non-limiting example of a preferred dispersion comprising about 25 wt.% Boron nitride particles in water is the ORPAC BORON NITRIDE RELEASECOAT-CONC product manufactured by ZYP Coatings, Inc. of Oak Ridge, Tennessee. See "ORPAC BORON NITRIDE RELEASECOAT-CONC", a technical bulletin of ZYP Coatings, Inc., incorporated herein by reference. The boron nitride particles in this product have an average size of less than about 3 micrometers and include about 1% magnesium aluminosilicate to bind the boron nitride particles to the dispersion substrate. Other products suitable for this invention manufactured by ZYP Coatings include BORON NITRIDE LUBRICOAT ^® , as well as BRAZE STOP and WELD RELEASE products. Specific non-limiting examples of emulsions and dispersions of synthetic polymer particles derived from acrylic polymers and copolymers include the following products: Rhoplex ^® GL-623 ²⁷ ( ²⁷ See product properties sheet entitled: "Rhoplex ^® GL-623, Self-Crosslinking Acrylic Binder of Industrial Nonwovens ", March 1997, from Rohm and Haas Company, Philadelphia, PA, incorporated by reference.), Which is an emulsion of a fully acrylic dense polymer, with a solids content of 45 wt.% And with a glass transition temperature of about 98 ^o C; EMULSION E-2321 ²⁸ ( ²⁸ See Product Properties Sheet, entitled; "Building Products Industrial Coatings - Emulsion E-2321", 1990, from Rohm and Haas Company, Philadelphia, PA, incorporated herein by reference.) , which is an emulsion of solid methacrylate polymer, with a solids content of 45 wt. % and with a glass transition temperature of about 105 ^o C; ROPAQUE ^® OP-96 (described above), supplied as a dispersion with a particle size of 0.55 micrometers and a solids content of 30.5 wt.%; ROPAQUE ^® OP-62-LO (described above), also representing a dispersion of an opaque, non-forming synthetic pigment with a particle size of 0.40 micrometers and with a solids content of about 36.5 wt.%; and ROPAQUE ^® HP-1055 (described above) may be supplied as a dispersion with a solids content of about 26.5 wt.%, all of which are available from Rohm and Haas Company, of Philadelphia, Pennsylvania.

Although not required, it is preferred that particles 24 are particles of non-hydratable inorganic solid lubricants. As used herein, the term “non-hydratable” means that solid inorganic lubricant particles do not react with water molecules to form hydrates and do not contain hydration or crystallization water. A "hydrate" is obtained by the reaction of water molecules with a substance in which the H-OH bond is unsplit. See the publications of R. Lewis, Sr., Hawley's Condensed Chemical Dictionary (12 ^th Ed. 1993) on pages 609-610, and T. Perros, Chemistry (1967) on pages 186 and 187, which are incorporated herein by reference. links. From the point of view of their structure, hydratable inorganic materials include at least one hydroxyl group in the crystal lattice layer (but do not include hydroxyl groups in the surface planes of the structure of a molecule or materials that absorb water on their surface planes due to capillary forces), for example, as shown in the structure of kaolinite, shown in figure 3.8 on page 34 of the publication of J. Mitchell, Fundamentals of Soil Behavior (1976), and as shown in the structure of the layered minerals 1: 1 and 1: 2 shown in FIGS. 18 and 19 respectively thus, in H. van Olphen, Clay Colloid Chemistry (2d Ed. 1977) on page 62, which is incorporated herein by reference. The “layer” of the crystal lattice is a combination of thin layers, which in turn are combinations of atomic planes. See Minerals in Soil Environments, Soil Science Society of America (1977), pages 196-199, which is incorporated herein by reference. The totality of the materials of the layers and the materials located between the layers (such as cations) is called the structure of the molecule (or part of the polymer molecule).

 Hydrates contain coordinated water, which coordinates the cations in the hydrated material and cannot be removed without destroying the structure, and / or structural water, which occupies voids in the structure, which increases electrostatic energy without disturbing the charge balance. See R. Evans, An Introduction to Crystal Chemistry (1948) on page 276, which is incorporated herein by reference.

 Although not preferred, the aqueous sizing composition may contain hydratable or hydrated inorganic solid lubricants in addition to the non-hydratable inorganic solid lubricants described above. Non-limiting examples of such hydratable inorganic solid lubricants are clay mineral phyllosilicates, including mica (such as muscovite), talc, montmorillonite, kaolinite and gypsum.

 Preferably, the coating composition is substantially free of hydratable particles of inorganic solid lubricants or abrasive particles of silica or calcium carbonate, i.e. included less than about 20 wt. % of particles of hydratable inorganic lubricants, abrasive particles of silica or calcium carbonate, based on the total weight of solids, more preferably less than about 5 wt.% and most preferably less than 0.001 wt.%.

 In an alternative embodiment of the present invention, particles 24 are obtained from organic polymeric materials selected from the group consisting of thermoset materials, thermoplastic materials, starches, and mixtures thereof. Suitable thermosetting materials include thermosetting polyesters, vinyl esters, epoxies, phenolic plastics, aminos, thermosetting polyurethanes, and mixtures thereof, such as are described below. Suitable thermoplastic materials include vinyl polymers, thermoplastic polyesters, polyolefins, polyamides, thermoplastic polyurethanes, acrylic polymers and mixtures thereof. Preferred organic particles are in the form of beads or hollow spheres.

Although not necessary, in one embodiment of the present invention, particles 24 are thermally conductive, i.e. have a thermal conductivity higher than about 30 watts per meter K, preferably higher than about 100 watts per meter K, and more preferably from about 100 watts to 2000 watts per meter K. In this description, the term "thermal conductivity" refers to the property of a particle 24 describing its ability to transfer heat through itself. See publication R. Lewis, Sr. , Hawley's Condensed Chemical Dictionary (12 ^th Ed. 1993) on page 305, which is incorporated herein by reference.

 The thermal conductivity of a solid material can be determined by any method known to those skilled in the art. For example, if the thermal conductivity of the material to be tested lies in the range from about 0.001 watts per meter K to about 100 watts per meter K, then the thermal conductivity of such material can be determined using the preferred method of protected hot plates in accordance with ASTM C -177-85 (incorporated by reference herein) at a temperature of about 300 K. If the thermal conductivity of the material to be tested is in the range from about 20 watts per meter K to approx Since about 1200 watts per meter K, the thermal conductivity of such a material can be determined using the protected hot-flow sensor method in accordance with ASTM C-518-91 (incorporated by reference herein). It has been found that materials having higher thermal conductivity can more quickly dissipate the heat generated during the drilling operation from the area of the hole, as a result of which the life of the drill tip increases. The thermal conductivity of the selected material from table A is included in table B.

 Although this is not necessary, in another embodiment of the present invention, the particles 24 are electrically insulating or have a high electrical resistivity, i.e., have an electrical resistance higher than about 1000 microohm-cm. The use of particles with high electrical resistivity is preferred for applications in conventional electronic circuit boards to inhibit the loss of electrical signals due to the conductivity of electrons through the reinforcing material. For special applications, such as electronic circuit boards for microwave equipment, as well as for applications involving electronic and electromagnetic interference, particles with high electrical resistivity are not required. The electrical resistivity of the selected materials from table A is included in table B.

 Those skilled in the art will recognize that particles 24 of a coating composition may include any combination or mixture of particles 24 described above. More specifically, particles 24 may include additional particles obtained from any of the materials described above used to produce particles 24.

 Particles of solid lubricant, if present, can comprise from about 1 to about 99 wt.% Of the coating composition based on the total weight of solids, preferably from about 1 to about 60 wt.%. In one of the embodiments of the invention, the coating composition may contain from about 2 to about 10 wt.% Boron nitride, based on the total weight of solids. In another embodiment of the invention, which uses a combination of various particles, the coating composition contains from about 20 to about 60 wt. % of particles 24, based on the total weight of solids, preferably from about 35 to about 55 wt.% and more preferably from about 30 to about 50 wt.%.

The coating composition may also include one or more plasticizers or surfactants that impart the same charge to the surface of the fibers, causing the fibers to repel from each other, which reduces friction between the fibers, i.e. These substances act as lubricants. Although not required, it is preferred that the plasticizers are chemically different from the polymeric materials described above. Although the coating composition may include up to about 60 wt.% Plasticizer, it is preferred that the coating composition is substantially free of plasticizers, i.e. so that it contains less than about 10 wt.% plasticizer and more preferably less than about 5 wt.% plasticizer. Examples of such plasticizers include cationic, nonionic or anionic plasticizers and mixtures thereof, such as amine salts of fatty acids, alkylimidazoline derivatives such as CATION X, manufactured by Rhone Poulenc of Princeton, New Jersey, acid solubilized fatty acid amides, fatty acid condensates and substituted polyethyleneimines and polyethyleneimine amide such as EMERY ^® 6717, a partially amidated polyethyleneimine, manufactured by Henkel Corporation of Kankakee, Illinois. For more information on plasticizers, see AJHall, Textile Finishing, 2 ^nd Ed. (1957) on pages 108-115, which is incorporated herein by reference.

The coating composition may include one or more emulsifiers for emulsifying or dispersing components of the coating composition, such as organic and inorganic particles. Non-limiting examples of suitable emulsifiers or surfactants include polyoxyalkylene block copolymers (such as the polyoxypropylene-polyoxyethylene copolymer PLURONIC ^™ F-108 manufactured by BASF Corporation from Parsippany, New Jersey), ethoxylated alkyl phenols (such as ethoxylated octylphenoxyethanol IGEPAL CA-630 (manufactured by GAF Corporation of Wayne, New Jersey), polyoxyethylene octyl phenyl glycol ethers, ethylene oxide derivatives of sorbitol esters, polyoxyethylene vegetable oils la (such as ALKAMULS EL-719 manufactured by Rhone-Poulenc), and nonylphenol surfactants (such as MACOL NP-6 manufactured by BASF from Parsippany, New Jersey). Typically, the amount of emulsifier may be from about 1 to about 30 wt.% Based on the total amount of solids of the coating composition.

 The coating composition may also include one or more lubricants that are chemically different from the polymeric materials and plasticizers described above, and which give the desired technological characteristics to the strands of fibers during weaving. Suitable lubricants can be selected from the group consisting of oils, waxes, greases and mixtures thereof. Non-limiting examples of wax materials suitable for use in this invention include water-soluble emulsifiable or dispersible wax materials such as vegetable, animal, mineral, synthetic or petroleum waxes, such as paraffin. Oils suitable for use in the present invention include both natural oils and semi-synthetic and synthetic oils. Typically, the amount of wax or other lubricant may be in the range from 0 to about 80 wt.% Based on the total dry weight of the sizing composition, preferably from about 1 to about 50 wt. %, more preferably from about 20 to about 40 wt.% and most preferably from about 25 to about 35 wt.%.

Preferred lubricants include waxes and oils having polar characteristics, and more preferably include highly crystalline waxes having polar characteristics and having melting points higher than about 35 ^{° C.} and higher, preferably higher than about 45 ^° C. Such materials are considered to improve performance wetness and impregnation of polar polymers on strands of fibers coated with sizing compositions containing such polar materials, compared with strands of fibers coated with appr tiruyuschimi compositions containing waxes and oils that do not have polar characteristics. Preferred polar lubricants include
esters obtained by the reaction of (1) monocarboxylic acid and (2) monohydric alcohol. Non-limiting examples of such fatty acid esters suitable for use in the present invention include cetyl palmitate, which is preferred (such as KESSCO 653 or STEPANTEX 653 manufactured by Stepan Company of Maywood, New Jersey), cetyl myristate (also manufactured Stepan Company, under the name STEPANLUBE 654), cetillaurate, octadecyl laurate, octadecyl myristate, octadecyl palmitate and octadecyl stearate. Other fatty acid ester lubricants suitable for use in the present invention include trimethylolpropanetripelargonate, natural spermaceti and triglyceride oils, such as (but not limited to) soybean oil, linseed oil, epoxidized soybean oil, and epoxidized linseed oil.

Although not preferred, the coating composition may include one or more other lubricants, such as non-polar petroleum paraffins, instead of or in addition to the lubricants described above. Non-limiting non-polar petroleum paraffins include MICHEM ^® LUBE 296 microcrystalline paraffin, POLYMEKON ^® SPP-W microcrystalline paraffin and PETROLITE 75 microcrystalline paraffin manufactured by Michelman Inc., from Cincinnati, Ohio and Petrolite Corporation, from Tuls, respectively.

 Although not necessary, if desired, the coating composition may also include a polymer-reactive diluent to further improve the lubrication of the strands of coated fibers of the present invention and to provide good suitability for weaving and knitting operations by reducing possible fluffing and the number of broken filaments during such manufacturing operations, and at the same time maintain compatibility with polymers. The term “polymer reactive diluent” as used herein means that the diluent includes functional groups capable of chemically reacting with the same polymer with which the coating composition is compatible. The diluent may be any lubricant with one or more functional groups reacting with a polymer system, preferably with functional groups reacting with an epoxy system, and more preferably with functional groups reacting with an FR-4 epoxy system. Non-limiting examples of suitable lubricants include lubricants with amino groups, alcohol groups, anhydride groups, acid groups, or epoxy groups. A non-limiting example of an amino group lubricant is a modified polyethyleneamine, such as EMERY 6717, which is a partially amidated polyethyleneimine manufactured by Henkel Corporation of Kankakee, Illinois. A non-limiting example of an alcohol group lubricant is polyethylene glycol, for example CARBOWAX 300, which is polyethylene glycol manufactured by Union Carbide of Danbury, Connecticut. A non-limiting example of an acid group lubricant is fatty acids, for example stearic acid and stearic acid salts. Non-limiting examples of epoxy group lubricants include epoxidized soybean oil and epoxidized linseed oil, for example FLEXOL LOE, an epoxidized linseed oil, and FLEXOL EPO, an epoxidized soybean oil, both manufactured by Union Carbide from Danbury, Connecticut, and LE-9300 epoxidized silicone emulsion manufactured by Witco Corporation OSi Specialties, Inc. of Danbury, Connecticut. Although this does not limit the scope of the present invention, the sizing composition may include a polymer-reactive diluent described above in an amount of up to about 15 wt.%, Based on the total dry weight of the sizing composition.

 Crosslinking materials, such as melamine formaldehyde, and plasticizers, such as phthalates, trimellitates, and adipates, may also be included in the coating composition. The amount of crosslinking agent or plasticizer may be from about 1 to about 5 wt.% Based on the total amount of solids of the coating composition.

 Other additives may be included in the coating composition, such as silicones, fungicides, bactericides and antifoam agents, typically in an amount of less than about 5% by weight. Organic and / or inorganic acids or bases may also be included in the coating composition in an amount sufficient to provide a pH of the coating composition of from about 2 to about 10. A non-limiting example of a suitable silicone emulsion is the LE-9300 epoxidized silicone emulsion, manufactured by OSi Specialties, Inc. of Danbury, Connecticut. An example of a suitable bactericide is the Biomet 66 antimicrobial compound manufactured by M&T Chemicals of Rahway, New Jersey. Suitable defoamers are SAG materials manufactured by OSi Specialties, Inc., from Danbury, Connecticut, and MAZU DF-136, manufactured by BASF Company, from Parsippany, New Jersey. If desired, ammonium hydroxide may be added to the coating composition to stabilize the coating. Preferably, water (preferably deionized) is included in the coating composition in an amount sufficient to facilitate uniform application of the composition to the strands, typically in an amount of about 25 to about 99% by weight. The mass percentage of solids in the coating composition is typically from about 1 to about 75 wt.%.

 The coating composition is preferably substantially free of glass materials. The expression "essentially does not contain glass materials", as used here, means that the coating composition includes less than 20 vol. % glass matrix materials for producing glass composites, preferably less than about 5 vol.%, and more preferably does not contain glass materials. Examples of such glass matrix materials include black glass ceramic matrix materials or aluminosilicate matrix materials well known to those skilled in the art.

In one non-limiting embodiment thereof, intended for manufacturing a fabric for the electronic circuit board of the present invention, glass fiber strands coated are supported on their primary layer of a dried residue of an aqueous sizing composition comprising boron nitride PolarTherm powder ^® 160 and / or dispersion boron nitride ORPAC BORON NITRIDE RELEASECOAT-CONC, polyvinylpyrrolidone PVP K-30, acryl-functional organosilicon A-174 and epoxy-functional organosilicon A-187, polyoxyethyl th e ALKAMULS EL-719 vegetable oil, a partially amidated polyethylene imine EMERY ^® 6717 polyester RD-847A, DESMOPHEN 2000 polyester, polyoxyethylene polyoxypropylene copolymer and PLURONICS F-108, alkoxylated nonylphenol ICONOL NP-6 and antifoam SAG 10.

In another embodiment of the present invention for manufacturing a fabric for the electronic circuit board of the present invention, glass fiber strands coated according to the present invention have applied to them a primary layer of a dried residue of an aqueous sizing composition comprising boron nitride PolarTherm powder ^® 160 and / or a dispersion of boron nitride ORPAC BORON NITRIDE RELEASECOAT-CONC, RD-847A polyester, PVP K-30 polyvinylpyrrolidone, DESMOPHEN 2000 polyester, A-174 acrylic-functional organosilicon, epoxy-functional organosilicon compound A-187, a copolymer of polyoxypropylene and polyoxyethylene PLURONICS F-108, polyamide VERSAMID 140 and nonylphenol MACOL NP-6.

In yet another embodiment of the present invention intended for fabric manufacture of laminated printed circuit boards, glass fiber strands coated according to the present invention have a primary layer of a dried residue of an aqueous composition for the primary dressing consisting of hollow spheres of styrene acrylic copolymer ROPAQUE ^® HP-1055 and / or ROPAQUE ^® OS-96, polyvinylpyrrolidone K-30 PVP, acryl-functional silane coupling agents and A-174 epoxy-functional silane coupling agent A-187, a partially amidated by ietilenimin EMERY ^® 6717, STEPANTEX 653 cetyl palmitate, ethylene oxide derivatives of sorbitol esters TMAZ 81, an ethoxylated alkylphenol MACOL OP-10 and antifoam MAZU DF-136. Furthermore, this embodiment may optionally comprise boron nitride PolarTherm powder ^® 160 and / or a dispersion of boron nitride ORPAC BORON NITRIDE RELEASECOAT-CONC.

 The coating compositions of the present invention can be obtained using any suitable method, such as conventional mixing, well known to specialists in this field of technology. Preferably, the components described above are diluted with water to have the desired solids content (in wt.%), And mixed. Powder particles can be pre-mixed with water or added to polymeric materials before mixing with other coating components.

The coating layer can be applied to the fibers in many ways, for example by contacting the filaments with a roller or tape applicator, by spraying, or by other methods. Coated fibers are preferably dried at room temperature or at elevated temperatures. Drying removes excess moisture from the fibers and, if any, cures any curable components of the coating composition. The temperature and drying time of the glass fibers depend on variables such as the percentage of solids in the coating composition, the components of the coating composition, and the type of glass fiber. Coating compositions are typically present as a dry residue of the sizing on the fibers in an amount between about 0.1 wt.% And about 25 wt.% After drying. The loss on ignition (LOI) of the fibers is generally less than about 1.0 wt.%, Preferably less than about 0.5 wt.%, And more preferably they are from about 0.01 to about 0.45 wt. .%. The term "loss on ignition" in the present description refers to the percentage (by weight) of the dried coating composition present on the surface of the fiber strand, determined using the following equation:
LOI = 100 • [(W _dry -W _{without the covering)} W _dry]
in which W _dry indicates the weight of the fiber strand plus the remainder of the coating composition after drying in an oven at a temperature of about 104 ^{° C.} for about 60 minutes, and W without coating indicates the weight of an uncoated fiber strand after removing the remainder of the coating composition by heating the fiber strand in an oven at a temperature about 621 ^{° C.} for about 20 minutes.

 The layer of the secondary coating composition can be applied to the layer of the coating composition described above in an amount effective to coat or impregnate part of the coated strands, for example, by dipping the coated strand in a bath containing the secondary coating composition, or by spraying the secondary coating composition on the coated strand, or by contacting the coated strand with the applicator as described above. The coated strand can be passed through a press to remove excess coating composition from the strand and / or dried, as described above, for a time sufficient to allow at least partial drying or curing of the secondary coating composition. The method and apparatus for applying the secondary coating composition to the strand is partially determined by the configuration of the strand material. The strand is preferably dried after application of the secondary coating composition, by a method well known in the art.

 Suitable secondary coating compositions may include one or more film-forming materials, lubricants, and other additives, such as those described above. The secondary coating is preferably different from the sizing composition, i.e. it (1) contains at least one component chemically different from the components of this sizing composition; or (2) contains at least one component in an amount different from the amount of the same component in said sizing composition. Non-limiting examples of suitable secondary coating compositions comprising polyurethane are described in US Pat. Nos. 4,762,750 and 4,762,751, which are incorporated herein by reference.

 In an alternative embodiment of the present invention, the glass fibers of the fiber strand may have a primary coating thereon consisting of a dried residue of a conventional sizing composition or sizing composition, which may include any of the sizing components in the amounts indicated above. Examples of suitable sizing compositions are presented in Loewenstein (3d Ed. 1993) on pages 237-291 and in US patents 4,390,647 and 4,795,678, which are incorporated herein by reference. A layer of a secondary coating composition suitable for the present invention and described herein is applied to at least a portion of the surface, and preferably to the entire outer surface of the primary coating. The secondary coating composition may include one or more of the types of particles described above and / or presented in table B. It is noted that some of these particles have a higher Mohs value than expected for fiberglass, i.e. from about 4.5 to about 6. However, since these particles are part of a secondary coating composition that does not directly contact the surface of the glass fibers, these higher hardness values do not adversely affect the glass fibers and are acceptable.

 Molybdenum disulfide and magnesium oxide are other inorganic particles suitable for use in the secondary and tertiary coatings of the present invention. Those skilled in the art will recognize that mixtures of any of the above inorganic particles can also be used in the present invention.

 In an alternative embodiment, the particles of the secondary coating composition include hydrophilic inorganic particles that absorb and retain water in the voids of the hydrophilic particles. Hydrophilic inorganic solids can absorb water or swell when they come in contact with water or participate in a chemical reaction with water, forming, for example, a viscous gel-like solution that blocks or inhibits the further flow of water into the voids of a telecommunication cable covered with fiberglass strands used for reinforcement. The word "absorb", as used here, means that water penetrates into the internal structure or into the voids of the hydrophilic material and is essentially retained in them. See the Hawley's Condensed Chemical Dictionary, on page 3, incorporated herein by reference. “Swell” means that the hydrophilic particles increase in size or volume. See Webster's New Collegiate Dictionary (1977), on page 1178, incorporated herein by reference. Preferably, the hydrophilic particles swell after contact with water at least one and a half times in relation to its initial dry weight, and more preferably about 2-6 times compared to the original weight. Non-limiting examples of hydrophilic inorganic particles of swellable lubricants include smectites such as vermiculite and montmorillonite, absorbent zeolites, and inorganic absorbent gels. Preferably, these hydrophilic particles are applied in powder form to a sticky sizing or other sticky secondary coating materials. The amount of hydrophilic inorganic particles in this embodiment of the secondary coating composition may be from about 1 to about 99 wt.% Based on the total weight of solids and preferably from about 20 to about 90 wt.%.

 The amount of inorganic particles in the secondary coating composition may be from about 1 to about 99 wt.% Based on the total weight of solids, and preferably from about 20 to about 90 wt.%. The percentage of solids in the aqueous composition of the secondary coating, as a rule, is from about 5 to about 75 wt.%.

 In another alternative embodiment of the present invention, the tertiary coating composition layer is applied to at least a portion of the surface, and preferably to the entire surface of the secondary coating, i.e. such a strand of fibers will have a primary coat coating layer, a secondary coating composition layer and an external tertiary coating layer. The tertiary coating preferably differs from the sizing composition and from the secondary coating composition, i.e. the tertiary coating composition (1) contains at least one component chemically different from the components of the sizing composition and the secondary coating composition; or (2) contains at least one component in an amount different from the amount of the same component in the sizing composition or in the secondary coating composition. A tertiary coating is applied to glass fibers and strands before or after they are incorporated into the fabric using methods (not limited to those listed), such as spraying or dipping, as previously described and well known to those skilled in the art.

In this embodiment, the secondary coating composition includes one or more of the polymeric materials described above, such as polyurethane, and the tertiary coating composition includes powdered, heat-conducting inorganic particles, such as PolarTherm ^® boron nitride particles, or hollow particles, such as the ROPAQUE ^® pigment described higher. Preferably, the powder coating is applied by passing the strands coated with the liquid secondary coating composition through a fluidized bed or spray device so that the powder particles adhere to the sticky secondary coating composition. Alternatively, the fabric 114 may be composed of strands before the tertiary coating layer 140 is applied, as shown in FIG. 4. The content of powdery heat-conducting inorganic particles adhered to the coated strand may be from about 0.1 to about 75 wt.% Based on the total weight of the dried strand. The tertiary coating may also include one or more of the polymeric materials described above, such as acrylic polymers, epoxy materials or polyolefins, conventional stabilizers and other modifiers known in the art of such coatings, preferably in the form of dry powders.

 Although it was mainly discussed above that the coating compositions of the present invention are applied directly to the glass fibers after the fibers are prepared and subsequently incorporated into the fabric, it will be understood by those skilled in the art that the present invention also includes an embodiment in which the coating composition of the present invention is applied to fabric after its manufacture using various methods known in the art. Depending on the fabrication technology, the coating composition of the present invention can be applied either directly to the glass fibers in the fabric or to another coating already on the glass fibers and / or the fabric. For example, glass fibers can be coated with a conventional starch-oil sizing after the fibers are obtained, and then weaved from them. Then the fabric can be processed to remove starch-oily sizing. The coating composition of the present invention described herein can then be applied directly to the fabric using well-known methods, such as (but not limited to) spraying or immersing the fabric in a bath with a sizing composition. The fabric can then be dried before further processing so that the remainder of the composition remains on the fibers and strands of the fabric. Removal of the sizing is carried out using methods well known in the art, such as heat treatment or washing the fabric. In this case, the coating composition is applied directly to the surface of the fabric fibers. If at least a portion of the sizing composition originally applied to the glass fibers after their preparation has not been removed, then in this case the coating composition of the present invention is applied to the remaining portion of the sizing composition, and not directly to the surface of the fibers.

 In another embodiment of the invention, the selected components of the coating composition of the present invention are applied to the glass fibers immediately after their preparation, and the remaining components of the coating composition are applied to the fabric after its manufacture. Just as described above, some of the selected components or all selected components can be removed from the glass fibers before coating these fibers and fabric with the remaining components. As a result, these other components either directly cover the surface of the fabric fibers, or they cover those selected components that have not been removed from the surface of the fibers.

 The woven fabric 14 is used as a reinforcing material to reinforce the materials 12 of the polymer matrix to form a composite or laminate 10, such as that shown in FIG. 1, preferably for use in electronic circuit boards. The warp and weft of the fabric 14 can be untwisted (also called zero torsion) or twisted before weaving using any conventional torsion methods known to those skilled in the art, for example using a twisting machine, to give the yarn from about 0.5 to 3 turns per inch (about 0.2 - 1.2 turns / cm). In addition, fabric 14 may include various combinations of both twisted and non-twisted weft and warp threads.

 Reinforcing fabric 14 may include from about 5 to about 100 warp threads per centimeter and preferably has from about 6 to about 50 warp threads per centimeter. The structure of the woven material can be a simple, simple woven fabric, although any other structure (type) of fabric (type of weaving) that is well known to those skilled in the art, such as twill weave or satin weave, can be used.

The fabric 14 is preferably made in the form of a structure that is suitable for the laminate used for printed circuit boards, such as described in the publication "Fabrics Around the World", which is a technical bulletin of the company Clark-Schwebel, Inc., from Anderson, South Carolina (1995) , which is incorporated into this description by reference. A non-limiting example of a fabric structure (type) of fabric using E225 E-glass fiberglass yarns is structure (type) 2116, in which the fabric has 118 warp and 114 weft 5 cm; warp and weft threads are used 7 22 1x0 (E225 1/0); the fabric has a nominal thickness of 0.094 mm; and the weight of the fabric is 103.8 g / m ² . A non-limiting example of a fabric structure using G75 E-glass fiberglass yarns is structure (type) 7628, in which the fabric has 87 warp threads and 61 weft threads of 5 cm; warp and weft threads are used 9 68 1x0 (G75 1/0); the fabric has a nominal thickness of 0.173 mm; and the weight of the fabric is 203.4 g / m ² . A non-limiting example of a fabric structure using D450 E-glass fiberglass yarns is a structure (type) 1080 in which the fabric has 118 warp yarns and 93 weft yarns of 5 cm; warp and weft threads are used 5 11 1x0 (D450 1/0); the fabric has a nominal thickness of 0.053 mm; and the weight of the fabric is 46.8 g / m ² . A non-limiting example of a fabric structure using E900 glass fiber D900 yarns is structure (type) 106, in which the fabric has 110 warp and 110 weft 5 cm; warp and weft threads are used 5 5.5 1x0 (D900 1/0); the fabric has a nominal thickness of 0.033 mm; and the weight of the fabric is 24.4 g / m ² . Another non-limiting example of a fabric structure using E900 glass fiber D900 yarns is structure (type) 108, in which the fabric has 118 warp yarns and 93 5 cm weft yarns; warp and weft threads are used 5 5.5 1x2 (D900 1/2); the fabric has a nominal thickness of 0.061 mm; and the weight of the fabric is 47.5 g / m ² . A non-limiting example of a fabric structure using both E225 and D450 E-glass glass fibers is structure (type) 2113, in which the fabric has 118 warp and 110 weft 5 cm; warp threads 7 22x0 (E225 1/0) and weft threads 5 11 1x0 (D450 1/0) are used; the fabric has a nominal thickness of 0.079 mm; and the weight of the fabric is 78.0 g / m ² . A non-limiting example of a fabric structure using glass fibers G50 and G75 of E-glass is structure (type) 7535, in which the fabric has 87 warp and 57 weft 5 cm; warp threads 9 68x0 (G75 1/0) and weft threads 9 99 1x0 (G50 1/0) are used; the fabric has a nominal thickness of about 0.21 mm; and the weight of the fabric is about 232.3 g / m ² . These and other suitable fabric structures (types) are given in IPC-EG-140 "Specification for Finished Fabric Woven from 'E' Glass for Printed Boards", a publication of The Institute for Interconnecting and Packaging Electronic Circuits (June 1997), which included in the present description by reference. Although twisted threads are used in the above-described fabric structures, it is understood that these and other fabric structures that use zero-torsion threads or rovings, together with or instead of twisted threads, can also be made in accordance with the present invention. It is also understood that some or all warp yarns in a fabric may have fibers coated with a first polymer-compatible sizing composition, and some or all weft yarns in a fabric may have fibers coated with a second polymer-compatible coating that is different from the first composition, i.e. . the second composition (1) contains at least one component chemically different from the components of the first sizing composition; or (2) contains at least one component in an amount different from the amount of the same component contained in the first sizing composition.

 A suitable reinforced woven fabric 14 used in the present invention is obtained using any conventional weaving machines well known to those skilled in the art, such as a shuttle weaving machine or rapier weaving machine, but preferably it is obtained using a pneumatic weaving machine. In the manufacture of fabric using a pneumatic weaving method, a pneumatic weaving machine inserts a weft thread into the throat of a weaving machine and moves the thread through the width of the fabric using a jet of compressed air supplied by one or more air jets. Pneumatic looms manufactured by Tsudakoma from Japan in the form of models 103, 1031, 1033, as well as Sulzer Ruti, models L-5000, L-5100 or L-5200 manufactured by Sulzer Brothers LTD, from Zurich, Switzerland are preferred. See the publications Sulzer Ruti L-5000, L-5100 and L-5200 Product Bulletins, technical bulletins from Sulzer Brothers LTD, Switzerland, incorporated herein by reference.

 In FIG. 1 shows that fabric 14 is used to produce laminate 10 by coating and / or impregnating one or more layers of fabric 14 with polymer thermoplastic or thermosetting matrix material 12. Laminate 10 is suitable as a base for electronic circuit boards.

Matrix materials suitable for use in the present invention include thermosetting materials, such as thermosetting polyesters, vinyl esters, epoxides (containing at least one epoxy or oxirane group in their molecule, such as polyglycidyl ethers of polyhydric alcohols or thiols), phenoplasts , aminos, thermosetting polyurethanes, their derivatives and their mixtures. Preferred matrix materials for the manufacture of laminates for electronic circuit boards are epoxy resins FR-4, polyimides and liquid crystalline polymers, compositions of which are well known to those skilled in the art. If you want more information about these compositions, see. 1 Electronic Materials Handbook ^TM, ASM International (1989), pages 534-537.

 Non-limiting examples of suitable thermoplastic polymer matrix materials include polyolefins, polyamides, thermoplastic polyurethanes and thermoplastic polyesters, vinyl polymers and mixtures thereof. Other examples of suitable thermoplastic materials include polyimides, polyethersulfones, polyphenyl sulfones, polyether ketones, polyphenylene oxides, polyphenylene sulfides, polyacetals, polyvinyl chlorides and polycarbonates.

 Suitable matrix material compositions include EPON 1120-A80 epoxy resin, dicyandiamide, 2-methylimidazole and DOWANOL PM.

 Other components that can be included in the composite, along with the polymer matrix material and reinforcing material, include dyes or pigments, lubricants or processing aids, UV stabilizers, antioxidants, and various fillers.

 The fabric 14 can be coated or soaked by immersing the fabric 14 in a bath of polymer matrix material 12, for example, as described in R. Tummala (Ed.), Microelectronics Packaging Handbook (1989) on pages 895 and 896, which is included in the present description by reference. From the polymer material 12 of the matrix and fabric 14, it is possible to obtain a composite or laminate 10 using various methods, the choice of which depends on factors such as the type of polymer matrix material used. For example, in the case of a thermosetting matrix material, a laminate can be obtained by extrusion or injection molding, a method for producing a uniaxially oriented laminate, manually laying layers, or by sheet molding followed by extrusion or injection molding. Thermosetting polymer matrix materials can be cured by incorporating crosslinking agents into the matrix material and / or, for example, by heat treatment. Suitable crosslinking agents suitable for crosslinking polymer matrix materials are described above. The temperature and curing time of the thermosetting polymer matrix material depend on factors such as the type of polymer matrix material used, the presence of other additives in the matrix system, the thickness of the composite, etc.

 As for thermoplastic matrix materials, suitable methods for producing composites include direct molding or extrusion mixing followed by injection molding. Methods and devices for producing composites by the above methods are described in publication I. Rubin, Handbook of Plastic Materials and Technology (1990) on pages 955-1062, 1179-1215 and 1225-1271, which is incorporated herein by reference.

 Although this does not limit the scope of the present invention, in one of the embodiments of the invention shown in FIG. 5, the composite or laminate 210 includes a fabric 214 impregnated with a compatible matrix material 212. Then, the impregnated fabric can be squeezed out by passing between the metering rollers or bars so that a measured amount of matrix material remains on it, and then dried to obtain the base of the electronic circuit board in the form of a semi-cured substrate or prepreg (prefabricated laminate). The conductive layer 250 is arranged along part of the side of the prepreg 252 as described below, after which the prepreg is cured to form a laminate 210, which is used as the base 254 of the electronic circuit board with the conductive layer. In another embodiment of the present invention, and more typically in the field of electronic circuit boards, two or more prepregs are combined with one or more electrically conductive layers, laminated together and cured by a method well known to those skilled in the art, resulting in an electronic circuit board. By way of example, but not limited to, prepregs stacked on top of each other can be laminated by pressing a stack of prepregs, for example, between polished steel plates, at elevated temperatures and elevated pressures, for a predetermined amount of time to cure the polymer matrix and obtain a laminate of the desired thickness . A portion of one or more prepregs may be provided with an electrically conductive layer, either before or after lamination and curing, so that the resulting electronic circuit board is a laminate having at least one electrically conductive layer along a portion of the exposed surface (hereinafter referred to as “foil laminate”) .

 Then, from the electrical conductive layer (s) of the single-layer or multi-layer base of electronic circuit boards using methods well known in the art, it is possible to make circuits with the subsequent manufacture of the base of an electronic circuit board (electronic structural material) in the form of an electronic circuit board.

If desired, holes can be made in the base of the electronic circuit board (also called "through holes") to provide electrical connection between circuits and / or components located on opposite sides of the base of the electronic circuit board in any convenient manner known in the art, including but not limited to, mechanical drilling and laser drilling. More specifically, as shown in FIG. 6, the aperture 360 passes through at least one layer 362 of fabric 312 of the circuit board base 354 of the present invention. The fabric 312 includes strands of coated fibers containing at least one glass fiber having a layer compatible with various polymer matrix materials, as described herein. When forming the hole 360, the base 354 electronic circuit boards are placed in a register with a device for manufacturing
holes such as a cutting edge of a drill 364 or a laser tip. The hole 360 is made through part 366 of at least one layer 362 of fabric 312 by drilling with a drill 364 or a laser. After making the holes, a layer of conductive material is applied to the walls of these holes or the hole is filled with conductive material to provide the necessary electrical connection between one or more conductive layers (not shown in FIG. 6) on the surface of the base of the electronic circuit board 354 and / or heat transfer.

 An electrically conductive layer, for example, such as that shown in FIG. 5 as layer 250, can be obtained by any method well known to those skilled in the art. By way of example, but not limiting to the scope of the present invention, an electrically conductive layer can be obtained by laminating a thin sheet or foil of a metal material on at least a portion of the side of a semi-cured or cured prepreg or laminate. Alternatively, an electrically conductive layer can be obtained by applying a layer of metallic material to at least a portion of the side of the semi-cured or cured prepreg or laminate using well-known methods, including, but not limited to, electrolytic coating, chemical reduction coating or spraying. Metallic materials suitable for use as an electrically conductive layer include, but are not limited to, copper (which is preferred), silver, aluminum, gold, tin, tin and lead alloys, palladium, and combinations thereof.

 In another embodiment of the present invention, the base of the electronic circuit board is made in the form of a multilayer electronic circuit board constructed by co-laminating one or more electronic circuit boards (described above) with one or more foil laminates (described above) and / or with one or more prepregs (described above) ) Optionally, additional electrically conductive layers can be included in the basis of electronic boards, for example, along a portion of the open side of a multilayer electronic board. In addition, if necessary, additional circuits can be made from the electrically conductive layers as described above. It should be borne in mind that, depending on the relative arrangement of the layers of the multilayer electronic board, the board can have both internal and external circuits. Additional holes can be drilled, as described above, partially through the board or completely through the board to provide an electrical connection between the layers at selected locations. It should be borne in mind that the resulting structure may have several holes passing through the entire structure, several holes passing partially through the structure, and several holes that are completely inside the structure.

 Preferably, the thickness of the laminate forming the backbone of 254 electronic boards is more than about 0.051 mm, and more preferably from about 0.13 mm to about 2.5 mm. For an eight-layer laminate of fabric type (structure) 7628, the thickness, as a rule, is about 1.32 mm. The number of layers of fabric 14 in the laminate 10 may vary depending on the desired thickness of the laminate.

 The polymer content in the laminate may be from about 35 to about 80 wt. %, and more preferably from about 40 to about 75 wt.%. The amount of fabric in the laminate may be from about 20 to about 65 wt.%, And more preferably from about 25 to about 60 wt.%.

For a laminate obtained from a fabric woven from Bg glass fibers and using FR-4 epoxy as a matrix material having a minimum glass transition temperature of about 110 ^{° C.} , the desired minimum bending strength across the weaving machine, or the width direction of the fabric (typically perpendicular to the longitudinal axis of the fabric) is more than 3 • 10 ⁷ kg / m ² , preferably more than 3.52 • 10 ⁷ kg / m ² and more preferably more than 4.9 • 10 ⁷ kg / m ² according to the specification for basic materials for rigid and IPC-4101 Multilayer PCB Specification for Base Materials for Rigid and Multilayer Printed Boards, on page 29, which is a publication from The Institute for Interconnecting and Packaging Electronic Circuits (December 1997). The IPC-4101 specification is incorporated herein by reference in its entirety. The desired minimum bending strength in the length direction (usually parallel to the longitudinal axis of the fabric) is more than about 4 • 10 ⁷ kg / m ² and preferably more than 4.23 • 10 ⁷ kg / m ² . Bending strength is measured in accordance with ASTM D-790 and IPC-TM-650 standard methods set forth in ASTM D-790 and IPC-TM-650 Test Methods Manual of the Institute for Interconnecting and Packaging Electronic Circuits (December 1994) (which is incorporated herein by reference), when a metal layer is completely removed by etching, according to part 3.8.2.4 of IPC-4101 specification. The advantages of the fundamentals of the electronic circuit boards of the present invention include high flexural strength (tensile strength and compressive strength) and a high modulus, which reduces the deformation of the electronic circuit board including this laminate.

The electronic circuit boards of the present invention in the form of copper foil laminate based on epoxy resin FR-4 preferably have a thermal expansion coefficient of 50 ^° C to 288 ^° C in the z-direction of the laminate ("Z-CTE"), i.e. in the direction through the thickness of the laminate, or less than about 5.5%, and more preferably from about 0.01 to about 5.0 wt.% in accordance with IPC 2.4.41 for test methods (IPC Test Method 2.4.41 ), which is incorporated herein by reference. Each such laminate preferably contains eight layers of fabric structure (type) 7628, although tissue structures (types) 106, 108, 1080, 2113, 2116 or 7535 can also be used as an alternative. In addition, the laminate may include combinations of these types of fabrics. Laminates with low thermal expansion coefficients are generally less susceptible to expansion and contraction, which reduces the likelihood of curvature of electronic circuits.

The present invention also relates to the manufacture of multilayer laminates and electronic boards, which include at least one composite layer made in accordance with the methods of the present invention, and at least one composite layer made by a method different from the composite manufacturing method described in this application, for example, made using conventional technology for producing fiberglass composites. More specifically, as is well known to those skilled in the art, traditionally, filaments in continuous fiberglass strands used to weave a fabric are treated with a starch-oil dressing comprising partially or fully dextrinized starch or amylose, hydrogenated vegetable oil, a cationic wetting agent, emulsifier and water, including, but not limited to, the components listed in the Loewenstein publication (3d Ed., 1993) on pages 237-244, incorporated herein by reference. The warp threads are obtained from these strands, and then they are treated with a solution before weaving to protect the strands from abrasion during weaving, for example with a solution of polyvinyl alcohol, as described in US Pat. No. 4,530,876, column 3, line 67, column 4, line 11, which is incorporated herein by reference. This operation is commonly referred to as "hatching." Polyvinyl alcohol, like starch oil, is generally not compatible with the polymer matrix material used by composite manufacturers, and the fabric must be cleaned to remove substantially all organic material from the surface of the glass fibers before impregnating the woven fabric. This can be done using various methods, for example, by washing the fabric or, more commonly, by heat treating the fabric in a manner well known in the art. As a result of cleaning operations, there is no necessary pairing between the polymer matrix material used to impregnate the fabric and the cleaned surface of the glass fibers, therefore, a sizing composition must be applied to the surface of the glass fibers. This operation is sometimes referred to as finishing in the art. The finishes most commonly used in finishing operations are silanes (organosilicon finishes), including but not limited to those listed in EP Plueddemann, Silane Coupling Agents (1982), pages 146-147, which are incorporated herein by reference. See also Loewenstein (3d Ed., 1993) on pages 249-256. After silane treatment, the fabric is impregnated with a compatible polymer matrix material, squeezed between the metering rollers and dried to obtain the semi-cured prepreg described above. It should be borne in mind that depending on the type of sizing, the type of cleaning operation and / or the matrix material used in the composite, the hatching and / or finishing stages can be excluded. One or more prepregs, including fiberglass composites made by conventional technology, can then be combined with one or more prepregs made in accordance with the present invention, resulting in the above-described electronic base, and in particular, a multilayer laminate or electronic board. For more information regarding fabrication of electronic circuit boards, see. In the publications 1 Electronic Materials Handbook ^TM, ASM International (1989), pages 113-115, R. Tummala (Ed.) , Microelectronics Packaging Handbook ( 1989), pages 858-861 and 895-909, MWJawitz, Printed Circuit Board Handbook (1997) on pages 9.1-9.42, and C.F. Coombs, Jr. (Ed.), Printed Circuits Handbook (3d Ed. 1988) pages 6.1-6.7, which are incorporated herein by reference.

 The composites and laminates that form the basis of the electronic boards of the present invention can also be used to obtain structural modules used in the electronics industry, and more specifically, structural modules of the first, second and / or third levels, such as described in the publication R. Tummala on pages 25- 43, incorporated herein by reference. In addition, the present invention can also be applied to structural modules of other levels.

 The present invention is further illustrated by the following specific examples, not limiting the scope of the invention.

EXAMPLE 1
Electrical laminates made from prepregs, including fabrics with yarns, on which various sizing compositions were applied, were tested to evaluate their drillability properties, and more specifically, (i) the wear of the cutting edge of the drill or drills used to drill holes through the laminates and ( ii) tested the accuracy of the placement of holes drilled through laminates. Control A and sample B were laminates comprising tissue structure (type) 7628 described above. The fabric in Control A was a thermally cleaned and silicone treated fabric manufactured by Clark Schwebel, under the name Fabric 7628-718. The fabric in Sample B was woven from yarns including glass fibers coated with a polymer compatible sizing as described herein and presented in Table 1. The glass fibers used to fabricate the fabric of Sample B had an annealing loss of 0.35%.

The prepregs were prepared by manual layering with a standard FR-4 epoxy resin (EPON 1120-A80 resin manufactured by Shell Chemical Co.) applied to the fabric using a brush. The resin-saturated fabric was immediately “dried” and B-steps were carried out in a hot air-ventilated oven for about 3 to about 3.25 minutes at a temperature of 163 ^{° C.} until a desired gelation time of 124 seconds was reached at a temperature 171 ^o C. Prepregs were cut into pieces of 46x46 cm and weighed to determine the resin content. For the subsequent lamination procedure, only prepregs with a resin content of 44 ± 2% were used.

The prepregs were stacked in 8 pieces and molded in a Wabash Press for 70 minutes at 177 ^° C and a pressure of 345 Newton / cm ² . All laminates were molded without layers of copper foil. Laminates exhibited varying levels of air uptake. The authors believe that this was facilitated by insufficient vacuum and insufficiently smooth temperature rise during lamination.

Tool wear analysis
The first series of tests was performed to assess the wear of the drill tip. Tip wear was expressed as “percent wear on the tip of the drill,” which was calculated using the following formula:
Percentage of wear on the cutting edge of the drill = 100 • (P _i -P _f ) / P _i ,
where P _i represents the initial width of the primary cutting edge;
P _f represents the width of the primary cutting edge after drilling the marked holes.

 7, the width 470 of the primary cutting edge 472 of the drill 474 was measured at the outer edge of the drill tip.

 Drilling was carried out using a single-head drilling machine. Drilling was carried out on piles of laminates with a height of 3 layers (described above), covered on top with a sheet of aluminum with a thickness of 0.203 mm and with a substrate made of phenolic coated paper with a thickness of 1.88 mm. Drilling three laminates at the same time is standard practice in the industry. The percentage of wear on the drill tip was determined for two drill diameters: 0.35 mm and 0.46 mm. Both drills were 508 series tungsten carbide drills manufactured by Tulon Co., Gardenia, California. The feed per revolution during drilling was maintained at a constant level of 0.001 for each tool. In the present description, the term "feed per revolution" refers to the ratio of the speed of the recess of the drill, measured in inches per minute, to the speed of rotation of the spindle, measured in revolutions per minute (rpm). For a drill with a diameter of 0.35 mm, the spindle speed was 100,000 rpm, and the speed of the recess of the drill was 100 inches (254 cm) per minute. For a drill with a diameter of 0.46 mm, the spindle speed was 80,000 rpm, and the speed of the recess of the drill was 80 inches (203 cm) per minute. The reverse speed of 2.54 m / min and the upper limit of the drill head of 1.65 mm were maintained at the indicated constant level for both drill diameters. As used herein, the term “drill head boundary” refers to the distance that the tip of the drill is raised above the upper surface of the laminate.

 The percentage of wear on the cutting edge of the drill was determined based on the drilling of 500 holes in a specific pattern, as shown in FIG. 8, where 391 holes were drilled with blocks measuring 0.635 cm x 10.16 cm (section 580), then 100 holes were drilled with an arrangement of 10x10 holes (section 582), and then 9 holes were drilled with a location of 3x3 holes (section 584). The holes in each section were drilled with a hole density of 62 holes per square centimeter. This hole pattern was repeated 3 more times, and a total of 2,000 holes were drilled. Test holes 1 and 2 were drilled using a Uniline 2000 single-head drilling machine, and Test 3 holes were drilled using a CNC-7 single-head drilling machine. Both machines are manufactured by Esterline Technologies, of Bellevue, Washington.

 Table 2 shows the percentage of wear of the cutting edge of the drill for inspection A and sample B, for drill diameters of 0.35 and 0.46 mm, after drilling 2000 holes located according to the above scheme. Each test began with a new cutting edge of the drill.

 As can be seen from table 2, sample B in tests 1 and 2, which included fiberglass yarns coated with a sizing composition of the present invention compatible with laminate matrix polymers, showed a significantly lower percentage of drill wear after 2000 holes than control A, which consisted of fiberglass yarn purified by heat treatment before applying the silicone finishing agent. Test 3 showed only a slight improvement in the percentage of wear of the drill, but the authors attribute this to the fact that the CNC-7 drilling machine used in this test was older and more difficult to control during testing than the Uniline 2000 drilling machine used in tests 1 and 2.

Hole accuracy
The usual measure of the drillability of a laminate (i.e., its behavior during drilling) is the accuracy of the location of the holes. In this test, the deviation of the actual location of the holes from their predetermined location is measured. The measurements were performed on the lower surface of the lower laminate from a 3-layer laminate set, where the holes exited from the set (stack) of laminate layers, since it is assumed that the location of the holes on this surface can have the greatest deviations from their "true" location. This difference was expressed by the term "deflection distance", i.e. the distance from the actual true center of the drilled hole on the surface of the laminate to the specified true center of the hole. The deviation distance was measured after four times the sequence of 500 holes described above, i.e., after each drill made 2000 holes in total. The deviation distance was measured for the last drilled set of 100 holes, i.e. for the last drilled section 582. The holes were drilled using a 0.46 mm drill bit of the 508 series manufactured by Tulon Co. of the type described above. As in the drill wear test, the spindle speed for this drill was 80,000 rpm, and the recess speed of the drill was 203 cm per minute, with a feed rate of 0.001. Each test was repeated 8 times for control A and for sample B, with each test starting with a new drill.

 Table 3 shows the results of the test for the accuracy of the location of the holes for control A and sample B after drilling 2000 holes.

 As you can see, sample B showed a smaller deviation distance than control A, which is especially important when the laminate is used as the basis of electronic boards, including a large number of holes and circuits. This is consistent with the results on the percentage of wear of the drill, shown in Table 2. More specifically, as one would expect, laminates providing a lower percentage of wear of the drill also show smaller distance deviations, since the cutting edge of the drill in this case will remain sharper for more holes to be drilled.

EXAMPLE 2
In Example 2, additional tests were performed on the percentage of wear of the drill. The electrical control laminates C and samples D, E and F, including fabric type 7628, described earlier, were tested for the percentage of wear of the drill. The fabric in control C was a fabric 7628-718 manufactured by Clark Schwebel, Inc. The fabrics in samples D, E, and F were woven from weft yarns including glass fibers coated with a polymer-compatible sizing composition described here and shown in Table 4, and warp yarns including glass fibers coated with another polymer-compatible matrix coating composition ¹⁰⁴ ( ¹⁰⁴ As the warp yarns, fiberglass yarn manufactured by PPG Industries, Inc., under the name G-75 fiberglass yarn, coated with size 1383 of PPG Industries, Inc., was used.

Then, prepregs with FR-4 epoxy resin having a glass transition temperature of about 140 ^{° C.} (called resin 4000-2 manufactured by Nelco International Corporation, from Anaheim, CA) were made from fabrics. Sizing compositions were not removed from the fabric prior to the preliminary impregnation of the glass fabric with resins (i.e., before the preparation of the prepregs). Laminates were made by stacking 8 layers of prepreg material and 4 layers of copper (1 ounce = 28.3 g each) and laminating them together at a temperature of about 179 ^o C and a pressure of about 2.1 MPa for about 150 minutes (total time cycle). The thickness of the laminates with copper ranged from about 0.132 cm to about 0.165 cm. Upon receipt of the laminates, eight layers of prepregs were stacked in a stack with layers of copper in the following order:
one layer of shiny copper (1 oz / ft ² )
three layers of prepregs
one layer of copper RTF foil (foil with a reverse side treated) (1 oz / ft ² )
two layers of prepregs
one layer of copper RTF foil (1 oz / ft ² )
three layers of prepregs
one layer of shiny copper (1 oz / ft ² )
For finished laminates, the edges were trimmed to a size of 40.6 by 50.8 cm.

 Drilling was performed using a Uniline 2000 single head drilling machine. Drilling was carried out on piles of laminates with a height of 3 layers (described above), coated on top with a sheet of aluminum with a thickness of 0.254 mm and with a substrate of aluminum foil-bonded wood chipboard (chipboard) 2.54 mm thick. The percentage of wear of the drill was determined for drills with a diameter of 0.34 mm, which were drills made of tungsten carbide series 80, manufactured by Tulon Co., Gardenia, CA. The feed per revolution during drilling was maintained at a constant level of 0.001 at a spindle speed of 95,000 rpm and a drill recess rate of 95 inches (241 cm) per minute. The speed of movement in the opposite direction was 2.29 m / min, and the value of the upper boundary of the drill head was 1.5 mm.

 The percentage of wear of the drill was determined based on the study of drilled holes located in a certain way in groups of 1,500 and 2,000 holes. The holes in each section were drilled with a hole density of 28 holes per square centimeter.

 Table 5 shows the values of the percentage of wear of the tip for control C and samples D, E and F after drilling 1500 and 2500 holes. Drilling of each set of holes began with a new cutting edge of the drill, and each stack of laminates had ten groups of 1500 holes and ten groups of 2500 holes. Three stacks of laminates were drilled for each type of fabric, so that the percentage of wear for 30 drills was determined for each sample.

 As can be seen from table 5, samples D, E, and F, which included glass fiber filaments coated with a sizing composition of the present invention compatible with laminate matrix polymers, showed a significantly lower percentage of wear on the drill tip after 1,500 holes than control C, which consisted of from fiberglass filaments to be cleaned before applying a silane-containing finishing dressing. After 2500 holes, the percentage of wear on the drill tip for samples D, E and F was still lower than in control C, but the difference was already less pronounced. This was to be expected, since the main wear of the tool occurs when drilling the first holes, and not when drilling the last holes in the group.

 Based on the foregoing, although this does not limit the scope of the present invention, it is preferable that the perpregs made of fiberglass fabric coated with a matting composition of the present invention compatible with matrix polymeric materials have an index of wear on the cutting edge of the drill of not more than about 32% , more preferably not higher than about 30%, and most preferably not higher than about 25%, which is determined after drilling 2,000 holes through a stack of 3 laminates, with each lamin m includes eight prepregs holes at a density of 400 holes per square inch and a load of drilled material is 0.001, when the drill diameter 0.46 mm, manufactured from tungsten carbide.

 In addition, based on the foregoing, although this does not limit the scope of the present invention, it is preferable that the perpregs made of fiberglass fabric coated with a matting composition of the present invention compatible with matrix polymeric materials have an opening deflection distance of not more than about 36 micrometers, more preferably not more than about 33 micrometers, and most preferably not more than about 31 micrometers, determined after drilling 2000 holes th through a stack of 3 laminates, each laminate comprising eight prepregs, with a hole density of 400 holes per square inch and a drill bit load of 0.001 when working with a 0.46 mm diameter drill made of tungsten carbide.

 Although the authors do not associate this with any theory, they believe that the presence of a solid lubricant in the glass fiber coating composition described herein, and in one specific embodiment of the invention, the presence of boron nitride, improves the luminosity properties of the laminates of the present invention. More specifically, solid lubricant helps to reduce wear on the drill and improve the accuracy of the location of drilled holes.

 The improved weldability characteristics of a laminate made of fiberglass coated with a polymer compatible sizing composition of the present invention provide several advantages. First, they provide a longer drill life, which means that the drill can drill more holes before it needs to be sharpened or replaced. In addition, since the accuracy of the placement of holes drilled through the laminates of the present invention is higher than for conventional laminates, the authors believe that when drilling these laminates, more than three laminates can be stacked on top of each other, and at the same time obtain the same accuracy. as when drilling a stack of three ordinary laminates. Both of these advantages result in increased economic efficiency of the drilling operation. In addition, the accuracy of the location of the holes drilled in the laminates is increased, and therefore, the quality of the bases of the electronic circuit boards including these laminates is improved.

 Specialists in the art it is clear that in the above embodiments of the invention, you can make changes that will not go beyond the idea of this invention in its broadest sense. Therefore, it is understood that the invention is not limited to the specific embodiments described herein, but encompasses modifications that do not go beyond the essence and scope of the present invention, which are defined by the appended claims.

Claims (56)

 1. A prepreg for the base of electronic circuit boards, comprising (a) a polymer matrix material, and (b) a fabric comprising a strand comprising fiberglass, at least a portion of the fabric has a coating that is compatible with the polymer matrix material, the prepreg having an indicator the percentage of wear of the drill, not exceeding 32%, determined after drilling 2,000 holes through a stack of three laminates, each of which includes eight prepregs, with a hole density of 62 holes per square centimeter and feed per revolution, 0.001 boiling, using a tungsten carbide drill of a diameter of 0.46 mm.  2. The prepreg according to claim 1, characterized in that the percentage of wear of the drill is not more than 30%.  3. The prepreg according to claim 2, characterized in that the percentage of wear of the drill is not more than 25%.  4. The prepreg according to claim 1, characterized in that the polymer matrix material includes at least one thermosetting matrix material selected from the group consisting of thermosetting polyesters, vinyl esters, epoxides, phenoplasts, aminos, thermosetting polyurethanes and their mixtures.  5. The prepreg according to claim 4, characterized in that the polymer matrix material includes at least one thermoplastic matrix material selected from the group consisting of polyolefins, polyamides, thermoplastic polyurethanes, thermoplastic polyesters, vinyl polymers, polyimides, polyethersulfones, polyphenyl sulfones, polyether ketones, polyphenylene oxides, polyphenylene sulfides, polyacetals, polycarbonates and mixtures thereof.  6. The prepreg according to claim 1, characterized in that at least one of the glass fibers is selected from the group consisting of glass fibers from E-glass, D-glass, S-glass, Q-glass, from derivatives of E-glass and from their combinations.  7. The prepreg according to claim 1, characterized in that the coating comprises solid lubricant particles.  8. The prepreg according to claim 7, characterized in that the particles of solid lubricant include at least one particle of a non-hydratable inorganic solid lubricant selected from the group consisting of graphite, boron nitride, metal dichalcogenides, cadmium iodide, silver sulfide, indium, thallium, tin, copper, zinc, gold, silver, calcium carbonate, calcium fluoride, zinc oxide, molybdenum disulphide, molybdenum disulide, tantalum disulphide, tantalum disulide, tungsten disulphide, tungsten diselide and mixtures thereof.  9. The prepreg according to claim 8, characterized in that the particles of a non-hydratable inorganic solid lubricant include boron nitride particles having a hexagonal crystal structure.  10. The prepreg according to claim 7, characterized in that the hardness of the particles of solid lubricant is less than or equal to the hardness of the E-glass fibers.  11. The prepreg according to claim 1, characterized in that the laminate includes eight layers of woven fabric selected from the group consisting of fabrics of type 106, type 108, type 1080, type 2113, type 2116, type 7535 and type 7628, and also their combinations.  12. The prepreg according to claim 1, characterized in that the coating comprises (1) a polyester, (2) at least one polymer selected from the group consisting of vinylpyrrolidone polymers, vinyl alcohol polymers and starches, as well as boron nitride particles .  13. The prepreg according to claim 1, characterized in that the coating comprises a plurality of discrete, stable particle sizes obtained from materials selected from the group consisting of organic materials, polymeric materials, composite materials and their mixtures, providing at least voids between one fiber and at least one adjacent fiber, the particles having an average size of from 0.1 to 5 microns.  14. The prepreg according to claim 13, characterized in that at least one of the particles comprises a polymeric material selected from the group consisting of inorganic polymeric materials, synthetic organic polymeric materials, semi-synthetic organic polymeric materials and natural organic polymeric materials.  15. The prepreg according to claim 14, characterized in that at least one particle comprises a thermoplastic organic polymer material selected from the group consisting of acrylic polymers, vinyl polymers, thermoplastic polyesters, polyolefins, polyamides, thermoplastic polyurethanes and mixtures thereof .  16. The prepreg according to claim 15, characterized in that at least one particle is obtained from an acrylic copolymer, which is a copolymer of styrene and acrylic.  17. The prepreg according to claim 16, characterized in that the particles are first particles, and the coating composition compatible with polymers also includes many additional discrete particles having stable particle sizes, different from the first particles and selected from the group consisting of metals, graphite, oxides, carbides, nitrides, borides, sulfides, silicates and carbonates.  18. The prepreg according to claim 13, wherein the coating comprises a lubricant selected from the group consisting of cetyl palmitate, cetyl laurate, octadecyl laurate, octadecyl myristate, octadecyl palmitate, octadecyl stearate and paraffin.  19. The prepreg according to claim 13, characterized in that the particles include boron nitride particles and hollow particles obtained from a styrene-acrylic copolymer.  20. The prepreg according to claim 1, characterized in that at least one of the glass fibers is at least partially coated.  21. The prepreg according to claim 1, characterized in that the fabric is selected from the group consisting of woven fabrics, non-woven fabrics, knitted fabrics and mats.  22. The prepreg according to claim 1, characterized in that the prepreg has a deflection distance of the drilled holes of not more than 36 μm, determined after drilling 2,000 holes through a stack of 3 laminates, each of which includes eight prepregs, with a density of holes at 62 holes per square centimeter and a feed per revolution of 0.001 when using a tungsten carbide drill with a diameter of 0.46 mm.  23. The prepreg according to claim 1, characterized in that at least a portion of the fabric includes a strand of twisted fiberglass.  24. The prepreg according to claim 1, characterized in that at least a portion of the fabric includes untwisted glass fibers.  25. The prepreg according to claim 1, characterized in that at least one glass fiber is made using the method of forming fibers directly from molten glass.  26. The prepreg according to claim 1, characterized in that at least one glass fiber is made using the method of forming fibers from molten glass balls.  27. The prepreg according to claim 1, characterized in that the fabric is a non-woven fabric.  28. The prepreg according to claim 1, characterized in that the fabric is a woven fabric.  29. The prepreg according to claim 28, wherein the fabric is woven on a pneumatic loom.  30. The prepreg according to claim 29, characterized in that at least one glass fiber is made using the method of forming fibers directly from molten glass and at least a portion of the fabric includes a strand of twisted glass fibers.  31. The prepreg according to claim 28, characterized in that it is woven on a rapier loom.  32. The prepreg according to claim 31, characterized in that at least one glass fiber is made using the method of forming fibers directly from molten glass and at least a portion of the fabric includes a strand of twisted glass fibers.  33. The prepreg according to claim 31, characterized in that at least one glass fiber is made using the method of forming fibers from molten glass balls and at least a portion of the fabric includes untwisted glass fibers.  34. A laminate comprising a prepreg according to claim 1.  35. A prepreg for the base of electronic circuit boards, comprising (a) a polymer matrix material, and (b) a woven reinforced fabric comprising glass fibers, at least a portion of the fabric being coated with a polymer matrix material, the prepreg having a distance indicator deviation of drilled holes, not more than 36 μm, determined after drilling 2000 holes through a stack of three laminates, with a hole density of 62 holes per square centimeter and a feed rate of 0.001, pr using a tungsten carbide drill of a diameter of 0.46 mm.  36. The prepreg according to claim 35, characterized in that the deflection distance of the drilled holes is not more than 33 microns.  37. The prepreg according to claim 36, characterized in that the deflection distance of the drilled holes is not more than 31 microns.  38. The prepreg according to claim 35, wherein the polymer matrix material includes at least one thermosetting matrix material selected from the group consisting of thermosetting polyesters, vinyl esters, epoxides, phenolic plastics, aminos, thermosetting polyurethanes and their mixtures.  39. The prepreg according to claim 38, wherein the polymer matrix material includes at least one thermoplastic matrix material selected from the group consisting of polyolefins, polyamides, thermoplastic polyurethanes, thermoplastic polyesters, vinyl polymers, polyimides, polyethersulfones, polyphenyl sulfones, polyether ketones, polyphenylene oxides, polyphenylene sulfides, polyacetals, polycarbonates and mixtures thereof.  40. The prepreg according to claim 35, characterized in that at least one of the glass fibers is selected from the group consisting of glass fibers of E-glass, D-glass, S-glass, Q-glass, derivatives of E-glass and from their combinations.  41. The prepreg according to claim 35, wherein the coating comprises solid lubricant particles.  42. The prepreg according to claim 41, wherein the particles of solid lubricant include at least one particle of a non-hydratable inorganic solid lubricant selected from the group consisting of graphite, boron nitride, metal dichalcogenides, cadmium iodide, silver sulfide, indium, thallium, tin, copper, zinc, gold, silver, calcium carbonate, calcium fluoride, zinc oxide, molybdenum disulphide, molybdenum disulide, tantalum disulphide, tantalum disulide, tungsten disulphide, tungsten diselide and mixtures thereof.  43. The prepreg according to claim 42, wherein the particles of a non-hydratable inorganic solid lubricant include boron nitride particles having a hexagonal crystal structure.  44. The prepreg according to claim 41, characterized in that the hardness of the particles of solid lubricant is less than or equal to the hardness of the E-glass fibers.  45. The prepreg according to claim 35, wherein the laminate comprises eight layers of woven fabric selected from the group consisting of fabrics of type 106, type 108, type 1080, type 2113, type 2116, type 7535 and type 7628, and also their combinations.  46. The prepreg of claim 35, wherein the coating comprises (1) a polyester, (2) at least one polymer selected from the group consisting of vinylpyrrolidone polymers, vinyl alcohol and starch polymers, and also nitride particles boron.  47. The prepreg according to claim 35, characterized in that the coating comprises a plurality of discrete, stable particle sizes obtained from materials selected from the group consisting of organic materials, polymeric materials, composite materials and mixtures thereof, which create voids, at least between one fiber and at least one adjacent fiber, the particles having an average size of from 0.1 to 5 microns.  48. The prepreg according to claim 47, wherein at least one of the particles comprises a polymeric material selected from the group consisting of inorganic polymeric materials, synthetic organic polymeric materials, semi-synthetic organic polymeric materials, and natural organic polymeric materials.  49. The prepreg of claim 48, wherein the at least one particle comprises a thermoplastic organic polymer material selected from the group consisting of acrylic polymers, vinyl polymers, thermoplastic polyesters, polyolefins, polyamides, thermoplastic polyurethanes and mixtures thereof .  50. The prepreg according to claim 49, characterized in that at least one particle is obtained from an acrylic copolymer, which is a copolymer of styrene and acrylic.  51. The prepreg according to claim 50, wherein the particles are first particles, and the polymer-compatible coating composition also includes many additional discrete particles having stable particle sizes, different from the first particles and selected from the group consisting of metals, graphite, oxides, carbides, nitrides, borides, sulfides, silicates and carbonates.  52. The prepreg according to claim 47, wherein the coating comprises a lubricant selected from the group consisting of cetyl palmitate, cetyl laurate, octadecyl laurate, octadecyl myristate, octadecyl palmitate, octadecyl stearate and paraffin.  53. The prepreg according to claim 47, wherein the particles include boron nitride particles and hollow particles obtained from a styrene-acrylic copolymer.  54. The prepreg according to claim 35, characterized in that at least one of the glass fibers is at least partially coated.  55. The prepreg according to claim 35, wherein the fabric is selected from the group consisting of woven fabrics, non-woven fabrics, knitted fabrics and mats.  56. A laminate comprising a prepreg according to claim 35.

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