Continuous carbon fiber composite segmented laminated articles and methods to form them

Abstract

A laminate article is comprised of a segment layer comprised of a plurality of unidirectional continuous fiber polymer composite members having a longitudinal edge parallel to the direction of the fibers of the unidirectional continuous fiber polymer composite member that are abutted forming a top and bottom face and a bonding layer comprised of an adhesive and a fabric that is adhered to the top face, bottom face or both faces. The laminate article may be useful to make assemblages useful to support molds for making complex fiber composite shapes such as vehicular fuselages. The unidirectional continuous fiber polymer composite members may be pultruded fiber polymer composites.

Description

CONTINUOUS CARBON FIBER COMPOSITE SEGMENTED LAMINATED ARTICLES AND METHODS TO FORM THEMFIELD

[0001] The invention relates to forming large load bearing articles comprised of segmented continuous fiber members laminated and bonded together within and between layers by a bonding layer comprised of a fabric and adhesive.BACKGROUND

[0002] Over many years in the transportation industry there has been a continuing shift from the use of metal materials to carbon fiber polymer composites. For example, whole monocoques have been formed of woven carbon fiber polymer composites (e.g., formula 1 racing vehicles). Likewise, fuselages of aircraft have been made of woven carbon fibers. These uses of carbon fiber composites have tended to be used in applications where weight and performance is of paramount importance (e.g., Formula 1 race cars and Aircraft e.g., "Boeing DREAMLINER"). These, however, have suffered from the expense and difficulty in processing the fiber composites and curing of the polymer without defects.

[0003] Typically, in the production of these large structural carbon fiber polymer composites articles, a carbon fiber-polymer prepreg is formed over a master tool to the desired shape and then cured at higher temperatures in an autoclave to form the article. To minimize defects, the tools typically need to have the necessary stiffness and coefficient of thermal expansion (CTE) to minimize defects and article rejects. The master tools have been made from invar (Fe-Ni alloys) having a similar CTE as the composite to be made. The tool or mold are supported by a lattice structure. The support frame typically has been made by materials that have a similar CTE as the invar mold.

[0004] Accordingly, it would be desirable to further decrease the weight and cost to make structural load bearing articles for use in the transportation, construction and energy applications.SUMMARY

[0005] Applicants have discovered that a large fiber composite may be made efficiently with desirable properties by bonding unidirectional continuous fiber polymer (UCFP) composite segments (segmented members) abutted along the edges running parallel with the fibers with a bonding layer comprised of an adhesive and a fabric to form large flat, corrugated sheets or other shapes having one dimension that is substantially liner (e.g., tubular or transected tubular shapes). Such a laminate article may be formed into lattices structures that may have complex contours aiding in the formation of load bearing articles with complex external shapes for supporting molds used to make fiber composite bodies (e.g., vehicular fuselages, cockpits, nose cones and the like) and in particular carbon fiber composite bodies. When referring to the continuous fibers being parallel or essentially parallel it is understood to encompass any minor deviation from perfectly straight from one end of the segmented member the fiber may take as commonly realized in commercially practicable methods of forming such composites such as found in pultrusion methods.

[0006] A first aspect of the invention is laminate article comprised of a segmented layer comprised of a plurality of unidirectional continuous fiber polymer composite members having a longitudinal edge parallel to the direction of the fiber of the unidirectional continuous fiber polymer composite member, the unidirectional continuous fiber polymer composite members are abutted forming a segmented layer face having the fibers in each member of the segmented layer being essentially parallel and a bonding layer comprised of an adhesive and a fabric that is adhered to the segmented layer face.

[0007] A second aspect is a method of forming a laminate article comprising,(i) contacting a unidirectional fiber polymer composite with another unidirectional fiber polymer composite to form an assembled segmented layer having a segmented layer face, the fibers being essentially parallel in the assembled segmented layer,(ii) contacting the segmented layer face with a bonding layer comprised of an adhesive and fabric, and(iii) curing the adhesive to form the laminate article, wherein the assembled segmented sheet is constrained during the contacting and curing to form the laminate article.DESCRIPTION OF THE DRAWI G

[0008] Figure 1 is a is perspective view of laminate article of this invention prior to formation.

[0009] Figure 2 is a cross-sectional view of a laminate article of this invention.

[0010] Figure 3 is a cross-sectional view of a laminate article of this invention.

[0011] Figure 4 is a cross-sectional view of a laminate article of this invention.DETAILED DESCRIPTIO

[0012] The explanations and illustrations presented herein are intended to acquaint others skilled in the art with the invention, its principles, and its practical application. The specific embodiments of the present disclosure as set forth are not intended to be exhaustive or limit the scope of the disclosure.

[0013] One or more as used herein means that at least one, or more than one, of the recited components may be used as disclosed. It is understood that the functionality of any ingredient or component may be an average functionality due to imperfections in raw materials, incomplete conversion of the reactants and formation of by-products.

[0014] An illustration of the laminate article prior to assembling is shown in Figure 1. Figure 2 is an illustration of the laminate article 10 having at least two unidirectional fiber polymer composite members ("segmented members") 20 in segment layers 24 and 25 and a bonding layer 30 comprised of a fabric infused with adhesive, which may include excess adhesive beyond that needed to only fill the voids in the fabric. Segmented layers 20 have fibers 40 running parallel to the longitudinal edges 50. The members are abutted along the longitudinal edges 50 to form the segmented layer 20 forming a segmentedlayer face 60. The members 20 in layers 24 and 25 have longitudinal edges 50 that are orthogonal to each other, but need not be. Further adhesive may be applied to the longitudinal edges 50 and any segmented layer face 60. When making the laminate article 10 (as illustrated in Figures 2 and 3), a layer of unidirectional fiber polymer members and fabric / adhesive layer may be placed in a die or mold (not shown) and pressed 70 with or without heating to form the laminate article 10.

[0015] The fibers of the of the segmented members generally lie in the same plane. That is, at least a portion of the continuous fibers 40 are parallel with the longitudinal edges 50 of each segmented member 20. All of the fibers may lie in the same plane.

[0016] Figure 2 illustrates the cross-section of laminate article 10 having bonding layers 30 encapsulating two segment layers 24 and 25 with the fibers 40 being parallel within each segment layer and orthogonal to the fibers in the other segment layer, with the fibers 40 of segment members 20 of segmented layer 25 projecting orthogonally from the plane of the drawing and the fibers 40 of segment members of segmented layer 24 lying in the plane of the drawing.

[0017] Figure 3 illustrates a laminate article 10 having a corrugated shape. In this illustration, the segment members 20 form a corrugated sheet where the fibers 40 and longitudinal edges 50 of the segmented members 20 are parallel and lie in the direction protruding outward from the plane of the drawing. Other shapes may be made in the same fashion such as tubular shapes and transected tubular shapes (e.g., U beams). Molds may be used to facilitate the fashioning of such shapes and may act as a mandrel where pressure and heat may be applied radially inward onto the laminate article surrounding the mandrel.

[0018] Figure 4 illustrates a laminate article 10 having the segmented members 20 having a segment faces 90, longitudinal edges 50 wherein the segmented members 20 are abutted on segmented faces 90 and longitudinal edges 50 and cavities 100 are formed on one segment layer face 60 that may be filled with further adhesive or foam (not pictured) and has bonding layer 30 bonding to the other segmented layer face 60 not having cavities. Flat face 60 (without cavities) is also shown having another bonding layer30. The segmented members 20 have continuous fibers 40 parallel to longitudinal edges 50 with the direction projecting outward from the plane of the drawing.

[0019] When laminating, any known laminating process may be used. Typically, when laminating, an adhesive as described herein is applied to at least a portion of the layer's faces and pressed to abut the segmented members, segment layers and bonding layers with sufficient pressure to realize the desired wetting and thickness to adhere the bonding layers and segment layers. The pressure may be sufficient to penetrate the fabric filling at least a portion or all of the voids within the fabric (voids between fibers).

[0020] Each segmented member may be made of a monolithic UCFP composite or may be comprised of laminates of multiple unidirectional continuous fiber polymer composites. The use of laminated segmented members may be desirable to realize desirable performance with making UCFP composites that have a thickness that is thin allowing for efficient penetration of the polymer / adhesive when forming the UCFP composite, for example by pultrusion.

[0021] The segmented members are abutted along their longitudinal edges to form a segmented layer having two faces (top and bottom). To at least one of the faces a fabric is adhered to the segmented members to form a bonding layer comprised of adhesive and fabric. One or both faces of each segmented layer may be bonded by a bonding layer to form a laminate of any practical amount of layers.

[0022] The segmented members are comprised of a unidirectional continuous fiber polymer (UCFP) composite. The UCFP may be comprised of any useful fiber such as those used to form pultruded UCFP composites. Desirably, the UCFP composite is comprised of continuous carbon fibers. Continuous means the fibers transverse the entire length (direction parallel to the fiber and longitudinal edge of the segment members) with it being understood that there may be an occasional fracture of a small amount of the fibers present in the segmented member (i.e., less than 1%, 0.1% or 0.01% by number of the fibers present in the segmented member). The segmented member may be further comprised of fibers other than carbon fibers. Other useful fibers that may be used in the UCFP composite may include any suitable, such as those known in the art with examples,being naturally occurring fibers (e.g., hemp, bamboo, jute, sisal, and coconut) metal fibers and glass fibers. When the UCFP composite is comprised of carbon fibers, all of the fibers may be carbon fibers, but other fibers may be present in any suitable amount depending on the desired characteristics, but typically are present in an amount of about 1%, 5%, 10% or 20% to about 99%, 95%, 75%, or 50% by volume of the fibers present in the UCFP having carbon fibers.

[0023] The UCFP composite may be any that enables the desired weight, cost and mechanical characteristics of the article. The UCFP composite is unidirectional. Illustratively, the UCFP is desirably a unidirectional continuous carbon rovings pultruded into a ribbons or sheets with a thermoset or thermoplastic resin penetrating and bonding the fibers together.

[0024] The UCFP composite is desirably a continuous carbon fiber polymer composite (CCFP composite). For example, the carbon fiber may one that is derived from any material that may be processed into a filament of desired size and carbonized. Typically, for carbon fibers, petroleum based pitches, polyamide or polyacrylonitrile may be used. The production of carbon fibers is well known with the following U.S. Pat. Nos., being illustrative: 3,294,489, 3,595,946, and 3,461,082. The fibers may be any useful diameter and typically may be from about 1 micrometer to 20, 50 or 100 micrometers in diameter. Examples of suitable fibers include those available from DowAksa under the tradename AKSAKA and from Toray Industries under the tradename ZOLTEK.

[0025] The polymer of the UCFP composite may be formed from a thermoplastic resin or polymer or thermosetting resin. Resin is used herein to denote that further curing or polymerization may occur when forming the UCFP composite, for example by pultruding. The thermoplastic materials as described herein generally encompass a plastic material or polymer that is reversible in nature. For example, thermoplastic materials typically become pliable or moldable when heated to a certain temperature and returns to a more rigid state upon cooling. Further, thermoplastic materials may include amorphous thermoplastic materials and / or semi-crystalline thermoplastic materials. For example, some amorphous thermoplastic materials may generally include, but are not limited to,styrenes, vinyls, cellulosics, polyesters, acrylics, polysulphones, and / or imides. More specifically, exemplary amorphous thermoplastic materials may include polystyrene, acrylonitrile butadiene styrene (ABS), polymethyl methacrylate (PMMA), glycolised polyethylene terephthalate (PET-G), polycarbonate, polyvinyl acetate, amorphous polyamide, polyvinyl chlorides (PVC), polyvinylidene chloride, polyurethane, or any other suitable amorphous thermoplastic material. In addition, exemplary semi-crystalline thermoplastic materials may generally include, but are not limited to polyolefins, polyamides, fluropolymer, ethyl-methyl acrylate, polyesters, polycarbonates, and / or acetals. More specifically, exemplary semi-crystalline thermoplastic materials may include polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polypropylene, polyphenyl sulfide, polyethylene, polyamide (nylon), polyetherketone, or any other suitable semi-crystalline thermoplastic material.

[0026] The thermoset materials as described herein generally encompass a plastic material or polymer that is non-reversible in nature. For example, thermoset materials, once cured, cannot be easily remolded or returned to a liquid state. As such, after initial forming, thermoset materials are generally resistant to heat, corrosion, and / or creep. Example thermoset materials may generally include, but are not limited to, polyesters, polyurethanes including polyurethanes having polyurea, esters, epoxies, or any other suitable thermoset material. Desirably, the polymer is comprised of polyurethane or epoxy. Exemplary thermosetting resins may include those described in U.S. Pat. Nos. 4,604,435 and 4,663,397, and a polyurethane resin-acrylate resin described in U.S. Pat. Appl. No. 2019 / 0375882, each incorporated herein by reference.

[0027] The UCFP composite typically has an amount of fibers sufficient to realize the load bearing capabilities and weight desired in the article. Typically, the amount of fibers is from about 20%, 30 or 50% to 70% or 80% by volume of the UCFP composite. The UCFP composite may be any shape such as those that may be produced by pultrusion (e.g., sheet, ribbon, tape, tubes, slitted tubes or rods) and as described in U.S. Pat. Publ. Nos. 2007 / 0117921 and 2018 / 0272566, but desirably have a longitudinal edge that may beabutted and adhered to a neighboring segmented member in the segment layer with ribbons being particularly useful.

[0028] The UCFP composite may also be comprised of other additives for imparting one or more desired characteristics. Examples, of other additives include fillers such as the fillers described herein below for use in adhesives and as follows: mica, talc, clay minerals (e.g., kaolin, , bentonite, smectite, montmorillonite), wollastonite, silica, calcium carbonate, glass beads, glass flakes, glass microballoons, molybdenum disulfide, titanium oxide, zinc oxide, antimony oxide, calcium polyphosphate, graphite, barium sulfate, magnesium sulfate, zinc borate, calcium borate, aluminum borate whisker, potassium titanate whisker, and high-molecular compounds. Other additives may include conductivity-imparting materials such as metal-based materials, metallic oxide-based materials, carbon black, and graphite powder; halogen-based flame retardants such as a brominated resin; antimony-based flame retardants such as antimony trioxide and antimony pentoxide; phosphorus-based flame retardants such as polyphosphate ammonium, aromatic phosphate, and red phosphorus; organic acid metallic salt-based flame retardants such as organic metal borate, metal carboxylate, and aromatic sulfonimide metallic salt; inorganic flame retardants such as zinc borate, zinc, zinc oxide, and zirconium compounds; nitrogen-based flame retardants such as cyanuric acid, isocyanuric acid, melamine, melamine cyanurate, melamine phosphate, and nitrogenated guanidine; fluorine-based flame retardants such as PTFE; silicone-based flame retardants such as polyorganosiloxane; metallic hydroxide-based flame retardants such as aluminum hydroxide and magnesium hydroxide; other flame retardants; flame retardant aids such as cadmium oxide, zinc oxide, cuprous oxide, cupric oxide, ferrous oxide, ferric oxide, cobalt oxide, manganese oxide, molybdenum oxide, tin oxide, and titanium oxide; pigments; colorants; lubricants; release agents; compatibilizers; dispersing agents; crystalline nucleus agents such as mica, talc, and kaolin; plasticizers such as phosphate ester; thermal stabilizers; antioxidants; color protectors; UV stabilizers; fluidity modifiers; foaming agents; antibacterial agents; vibration dampers; and antistatic agents such as polyether esteramide.

[0029] The other additives may include sizing agents such as those known in the art and may include resins of polyurethane, polypropylene, polyethylene, polycarbonate, polyetherimide, siloxane resins, polyketones, polysulfone, polyethersulfone, polyetheretherketone, polyetherketoneketone, polyphenylenesulfide, polyacrylates, polyvinylacetates, polyamide, polyesters, polyetherimide, polyamines, polyimides, epoxy resins, phenoxy resins, melamine resins, urea resins, polyamideimides, polyethersulfones, polyetheretherketones, polyetherketone ketones, polyphenylenesulfides and combinations thereof or precursors thereof that may be polymerized after being contacted with the carbon fiber or upon pultrusion with the polymer of the UCFP composite. The sizing agent may be an epoxy compound or adduct or isocyanate compound or adduct such as those described in U.S. Pat. Nos. 3,957,716; 10,501,605; and 11,118,022, each incorporated herein by reference.

[0030] The amount of other additives may be any useful amount for imparting a desired characteristic of the UCFP composite. Typically, the amount of other addtives may be an amount of about 0.1% or 1% to about 50%, 40%, 30% or 20% by volume of the UCFP composite.

[0031] Typically, it is desirable for the UCFP composite to be in a shape of a flat sheet, ribbon or tape with a width / thickness ratio of at least about 2, 5 or 10 to any practically useful ratio such as 200 or 100. Illustratively, the thickness typically is 0.1, 0.5, 1 mm to 10, 5 or 3 mm. Particularly suitable UCFP composites include those produced using a thermosetting resin and in particular ones comprised of polyurethane produced by a method such as described in U.S. Pat. Appl. No. 2018 / 0272566 employing the aforementioned polyurethane resin and commercially available polyurethane resins available from The Dow Chemical Company. Suitable UCFP pultruded composites, where polyurethane is the reinforcing polymer, are available from DowAksa. Any pultrusion process may be used such as those known in the art, with some illustrative examples being described in U.S. Pat. Nos. 4,643,126; 4,680,224; and 4,720,366.

[0032] The bonding layer is comprised of a fabric and an adhesive. The fabric may be comprised of any fiber useful in making a fiber polymer composite. The fabric may bewoven or non-woven (e.g., felt), knitted, multi-axial (e.g., non-crimped fabric), braided or any useful pattern. The fabric desirably is woven or knitted. The fibers may be any useful for making a textile that may be impregnated with an adhesive resin to impart the desired mechanical properties to the laminate article. Exemplary fibers may include those described for the UCFP composite segmented members. It may also be advantageous for the fabric to be the same chemistry as the fibers present in the UCFP composite of the segmented member (e.g., both are carbon fiber composites), but need not be.

[0033] Illustratively, the fibers of the fabric may be carbon fibers arranged in tows also referred to as rovings or simply fibers are multifilament fibers and may have from 100 to 30,000 individual fibers. The fibers of the fabric may be unidirectional, bidirectional or multidirectional depending on the desired properties of the laminate article. But, generally, the fibers are either bidirectional or multidirectional and if a felt may be chopped fibers having random orientation. The fabric may be comprised of stacks of fiber layers which are unidirectional in each layer and the direction of the fibers in each layer are at an angle.

[0034] When unidirectional fiber layers are used within the bonding layer, which may be a prepreg, the orientation of the fibers may be the same or vary throughout, for example, the prepreg thickness or stack. For example, the unidirectional fibers in neighboring layers may be arranged orthogonally to each other in a so-called 0 / 90 arrangement, which signifies the angles between neighboring fiber layers. Other arrangements, such as 0 / +45 / -45 / 90 may be used as well as other arrangements. An illustration of a prepreg that may be useful is described by U.S. Pat. Publ. No. 2018 / 0291164, incorporated herein by reference.

[0035] The adhesive may be any suitable such as those known in the art to make fiber polymer composites utilizing a fibrous fabric. The adhesive may have one or more fillers. Illustratively, the adhesive may be comprised of an epoxy, urethane, urea, formaldehyde, acrylate, silicone or any combination thereof. In some instances to realize the desired load bearing, the adhesive desirably has a lap shear of at least 5, 10 or 20 N / mm2at 20 °C or 40 °C, wherein the lap shear is measure in accordance with ISO 4587.

[0036] Epoxy is an illustration of the adhesive. The epoxy may be any comprised of an epoxy resin and a curing agent. The epoxy adhesive may be one that has a latent curing agent (or "hardner") or is a two-part epoxy where the curing agent and epoxy resin are mixed upon application. Another illustration is two component methacrylate adhesives such as those described by U.S. Pat. Nos. 4,536,546 and 9,657,203 and PCT Appl. No. W02008057414, which may also be comprised of epoxy compounds.

[0037] The epoxy resin may be saturated or unsaturated, aliphatic, cycloaliphatic, aromatic or heterocyclic and may be substituted. The epoxy resin may also be monomeric or polymeric. An extensive enumeration of epoxy resins useful in the present invention is found in Lee, H. and Neville, K., "Handbook of Epoxy Resins." McGraw-Hill Book Company, New York, 1967, Chapter 2, pages 257-307; incorporated herein by reference. The epoxy resins may be reaction products of polyfunctional alcohols, phenols, cycloaliphatic carboxylic acids, aromatic amines, or aminophenols with epichlorohydrin. A few examples include bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, resorcinol diglycidyl ether, and triglycidyl ethers of para-aminophenols. Other possible epoxy resins include reaction products of epichlorohydrin with o-cresol and, respectively, phenol novolacs. Further epoxy resins include epoxides of divinylbenzene or divinylnaphthalene. It is also possible to use a mixture of two or more epoxy resins. The epoxy resins may be selected from commercially available products such as those under the tradenames D.E.R. and D.E.N. available from Olin Chemical or Syna 21 cycloaliphatic epoxy resin from Synasia.

[0038] The curing agent may be any that has active chemical moiety that is reactive with the epoxy group of the epoxy resin. Any curing agent may be used alone or in combination with other curing agents. The curing agent may be any such as those known in the art. Examples include phenol-containing compounds, amines and combinations thereof. Illustratively, the curing agent may be primary and secondary polyamines and their adducts and polyamides. For example, polyfunctional amines may include aliphatic amine compounds such as diethylene triamine (D.E.H. 20, available from Olin Chemical), triethylene tetramine (D.E.H. 24, available from Olin Chemical), tetraethylene pentamine (D.E.H. 26, available from Olin Chemical), as well as adducts of the above amines withepoxy resins, diluents, or other amine reactive compounds. Aromatic amines such as metaphenylene diamine and diamine diphenyl sulfone, aliphatic polyamines, such as amino ethylpiperazine and polyethylenepolyamine, and aromatic polyamines such as metaphenylene diamine, diamino diphenyl Sulfone, and diethyltoluene diamine, may also be used as the curing agent. The curing agents may contain a sterically hindered amine group wherein an alkyl, cycloalkyl or aralkyl group is in close proximity to the amine group so that it is less reactive than in the case where the alkyl, cycloalkyl or aralkyl group is absent. An example of a curing agent having hindered amine groups are polyetheramines (for example, Jeffamine D-230 available from Huntsman Chemical), isophorone diamine (for example, Vestamin IPD from Evonik), bis(4-amino-3-methylcyclohexyl)methane (for example, Laromin C-260 from BASF). Further exemplary epoxy resins and hardner are described in U.S. Pat. PubL No. 2010 / 0151138 from paragraph 51 to 86, incorporated herein by reference.

[0039] The epoxy adhesive may be further comprised of other agents or additives to impart a desired result. For example, a toughener may be added. Examples of toughening agents include rubber particles. Examples and the amounts of toughening agents that may be suitable include those described in paragraphs 20 to 25 of U.S. Pat. Publ. No. 2015 / 0368457, incorporated herein by reference. The amount of additives may be any useful amount. Typically, the amount of additives is from 10% to 70% by volume of the adhesive.

[0040] The adhesive may incorporate other additives for a desired characteristic. For example, other useful additives may include, non-reactive diluents, stabilizers, surfactants, flow modifiers, pigments or dyes, matting agents, degassing agents, flame retardants (e.g., inorganic flame retardants, halogenated flame retardants, and nonhalogenated flame retardants such as phosphorus-containing materials), curing initiators, curing inhibitors, wetting agents, colorants or pigments, thermoplastics, processing aids, UV blocking compounds, fluorescent compounds, UV stabilizers, inert fillers, fibrous reinforcements, antioxidants, impact modifiers including thermoplastic particles, and mixtures thereof.

[0041] The fillers may be those conventionally used in adhesives. Illustrative examples include particulate ceramics such as, inorganic glass (e.g., beads and hollow beads), silicates (e.g., talc), clays, alumino-silicates (e.g., mullite), oxides (e.g., titanium dioxide, silica, calcium oxide, magnesium oxide and alumina), carbon (e.g., amorphous and graphitic) and metal powders. The fillers may be pretreated such as drying to remove moisture. The filler may have any useful size and, in some instances when a particular thickness of adhesive is desired, the size may be monosized (e.g., glass beads where at least 90% of the particles are within ±10% of the average diameter of the glass beads). The amount of filler typically is from 10% to 60% by volume of the adhesive. The size of the filler may be any useful. Typically, the size is from 5, 10 or 20 micrometers to 100, 250, or 500 micrometers equivalent spherical diameter and may be determined by any suitable method such as those known in the art. Illustratively, the particle size may be determined by, for example, laser diffraction or image analysis of micrographs of a sufficient number of particles (~100 to ~200 particles). A representative laser diffractometer is one produced by Microtrac such as the Microtrac S3500.

[0042] Polyurethane is another example of an adhesive. The polyurethane adhesive may be any known in the art and include those commercially available from Titebond and The Gorilla Glue Company. Likewise, a urea formaldehyde glue may be used such as available under the tradename Unibond 800. Exemplary urethane compounds useful in urethane adhesives are described in paragraphs 27 to 37 of U.S. Pat. Publ. No. 2010 / 0151138, incorporated herein by reference. In some instances, the polyurethane is further comprised of urea linkages due to the substitution of some of the polyols with a polyamine.

[0043] The laminate article may be further comprised of a cap or cap layer that is an outer layer on the outer faces of the laminate article. The cap may be comprised of any useful material depending on the desired application. For example, the cap may be comprised of a cellulosic material (e.g., wood, engineered lumber, and wood composites), metals (e.g., Mg, Al, Fe, Ti, or an alloy comprised of one of the aforementioned), polymers, fiber polymer composites, and ceramics (e.g., cements) and any composites, laminates,and structures comprised of 2 or more of the aforementioned. The cap may have a foam core.

[0044] The cap or cap layer may be formed by thermoforming a polymer sheet using a polymer capable of thermoforming such as thermoplastic materials (thermoplastic polymers) described herein, which may also be comprised of a fiber, filler or other additives such as those described herein, however, the fiber may also be chopped as commonly understood in the art (e.g., from about 0.5 mm to 10 mm in length). The cap layer may also be made of a thermoset material described herein where liquid or paste reactants are cast or pressed upon a mold, which may also be comprised of fibers, fillers or other additives. As a further illustration, the cap may also be formed by twin sheet thermoforming of two thermoplastic sheets that are, for example, heated to a temperature where they are moldable by a force (e.g., vacuum) to opposing mold surfaces and then joined, wherein the lattice is interposed between the sheets adding desired structural properties. The internal cavity formed by the two thermoformed sheets having the laminate article interposed between them may have a foam injected into the cavity to introduce further desired characteristics (e.g., mechanical, acoustical and thermal properties). The cavity may be comprised of cavities that are created as a consequence of the twin sheet thermoforming process and the foam may be injected in a portion of the cavity or cavities depending on the desired characteristics.

[0045] The foam is as commonly understood in the art meaning a body that is cellular. Cellular (foam) herein means the body has a substantially lowered apparent density compared to the density of the body's material (e.g., polymer, ceramic or metal) and the body is comprised of cells that are closed or open. Closed cell means that the gas within that cell is isolated from another cell by the polymer walls forming the cell. Open cell means that the gas in that cell is not so restricted and is able to flow to another cell without passing through any polymer cell walls to the atmosphere.

[0046] The size of the cells may be any useful size depending on the characteristics desired. Illustratively, the cells of the foam may have an average size (largest dimension) of 0.05 to 5.0 mm, especially from about 0.1 to about 3.0 mm, as measured by ASTM D-3576-98. Foams having larger average cell sizes, of especially about 1.0 to about 3.0 mm or about 1.0 to about 2.0 mm in the largest dimension, may be of particular use in load bearing applications.

[0047] Generally, the foam may have a density from about 16 kg / m3to about 100 kg / m3or more. The foam density, typically, is selected depending on the particular application, for example, for an exterior building facade panel, the density is desirably 24 kg / m3to about 64 kg / m3.

[0048] Typically, the foam is a polymer foam, but need not be. The foam typically has a porosity of at 30% or 50% to any practically useful porosity such as 95%. The foam may, for example, be an inorganic (metal or ceramic) foam, cement, aerogel or porous body. An adhesive may be used to bond those foams having insufficient adhesion to the laminate article or cap layer. The adhesive may be any suitable adhesive such as any one or more of those described herein.

[0049] The foam may have any amount of open or closed cells. Even so, for some applications a portion of the cells may be closed, for example, when absorption of water is deleterious to the function of the final product. Even though open or closed foams may be used, when the application desired benefits from lack of water absorption, the foam is preferably closed cell. For such applications, it is preferred, that at least about 55%, more preferably at least about 60%, even more preferably at least about 75% and most preferably at least about 90% of the cells of the foam are closed cells.

[0050] The polymer foam may be a thermoplastic or thermoset polymer foam. Any polymer that may be made into a foam may be used. Illustratively, the foam may be a polyurethane, polyurea, polyolefin, polyester, polycarbonate, polyacrylate, polyether, polyvinyl (e.g., polystyrene), polyvinylidene, polyetherester or any combination thereof. An illustration is the use of a polyurethane foam that is foamed.

[0051] Illustratively, the laminate article may be made by contacting a unidirectional fiber polymer composite (segmented member) along a common longitudinal edge with another segmented member to form an assembled segmented sheet having a face. The assembled segmented sheet is contacted with an adhesive and fabric as described aboveand the adhesive cured to form the laminate article, wherein the assembled segmented sheet is constrained during the contacting and curing to form the laminate article. The constraining may be by any suitable method and may merely include interlocking the segmented members (e.g., machining shapes along the longitudinal edges such as dovetails and the like), gluing the segmented members or mechanically constraining by clamping or insertion into a mold or die.

[0052] In an illustration, the fabric and adhesive are in the form of a prepreg. The segmented members may be placed in a die cavity on top of a prepreg (bonding layer) to form the assembled segmented sheet with as many alternating layers as desired placed within the mold or die. The prepreg may have a latent catalyst such as those described herein and upon heating the prepreg and the assembled segmented sheet are bonded forming the laminate article. Further adhesive may be place between each successive layer. Pressure may be applied during any portion of the method to facilitate the bonding and formation of the laminate article. The pressure may be applied unidirectionally (e.g., uniaxial die press) or isometrically (e.g., vacuum press). The method may further comprise forming a cap layer on the laminate article such as described above including forming the cap layer by twin sheet thermoforming.

[0053] The UCFP composites making up the segmented members and the laminate article may be machined by conventional techniques for use to make further useful assemblages. Two or more laminate articles may be assembled into an assemblage, for example, to support other structures such as molds for making continuous fiber polymer composite articles such as a vehicular nose, cockpit, fuselage, wing and vessels. Generally, the laminate article desirably has sufficient mechanical properties to allow for the support of molds (e.g., at least a bending strength of at least 500 pounds per square inch (psi) as per ASTM D7264. The assemblage may be a lattice structure that may be adhered using an adhesive as described herein and may include known joints for making such assemblages. When making support assemblages for molds, it may be desirable for the coefficient of expansion of the mold and the laminate article to be similar such that the mold / laminate article coefficient of thermal expansion (CTE) is 0.5, 0.75, 0.9 to 2, 1.5or 1.1. Illustratively the mold is a carbon fiber polymer composite or low CTE nickel based allow such as Invar (e.g., Ni / Fe alloy) and the fibers present in the laminate article are essentially all carbon fibers. Likewise, it may be desirable for the polymer / adhesive of the mold to be of like chemistry as present in the laminate article (e.g., epoxy and epoxy or polyurethane and polyurethane).Illustrative Embodiments

[0054] 1. A laminate article comprised of a segmented layer comprised of a plurality of unidirectional continuous fiber polymer composite members, the unidirectional continuous fiber polymer composite members are abutted forming a segmented layer face having fibers in each member of the segmented layer being essentially parallel and a bonding layer comprised of an adhesive and a fabric that is adhered to the segmented layer face.

[0055] 2. The laminate article of embodiment 1, wherein unidirectional continuous fiber polymer composite members are pultruded unidirectional continuous fiber polymer composites.

[0056] 3. The laminate article of either embodiment 1 or 2, wherein the laminate article is comprised of at least two segmented layers and the continuous fiber direction in at least one segmented layer is essentially parallel to another segmented layer.

[0057] 4. The laminate article of either embodiment 1 or 2, wherein the laminate article is comprised of at least two segmented layers and the fibers in at least one segmented layer are orthogonal to the fibers in another segmented layer.

[0058] 5. The laminate article of embodiment 4, wherein laminate article has a cap layer that covers at least a portion of a face of the laminate article.

[0059] 6. The laminate article of embodiment 5, wherein the cap layer is comprised of a thermoplastic polymer.

[0060] 7. The laminate article of embodiment 6, where the thermoplastic is comprised of one or more of an olefin, polyamide, polyester, thermoplastic polyurethane, a styrenic polymer or copolymer thereof.

[0061] 8. The laminate article of any one of the preceding embodiments, wherein the polymer of the unidirectional continuous fiber polymer composite is comprised of one or more of an epoxy, polyurethane or polyurea.

[0062] 9. The laminate article of embodiment 8, wherein the polymer is comprised of polyurethane.

[0063] 10. The laminate article of any one of the preceding embodiments, wherein the fabric is comprised of a fiber that is the same as the fiber of the unidirectional continuous fiber composite.

[0064] 11. The laminate article of any one of the preceding embodiments, wherein the fabric is comprised of one or more of a naturally occurring fiber, metal fiber, inorganic glass fiber, polymer fiber and carbon fiber.

[0065] 12. The laminate article of embodiment 11, wherein the fibers are carbon fibers.

[0066] 13. The laminate article of any one of the preceding embodiments, wherein the fabric is woven.

[0067] 14. The laminate article of any one of the preceding embodiments, wherein the adhesive has a filler.

[0068] 15. The laminate article of embodiment 14, wherein the filler has a particle size of about 5 to 500 micrometers equivalent spherical diameter.

[0069] 16. The laminate article of embodiment 15, wherein the filler is a graphite, ceramic, metal or inorganic glass beads, or inorganic glass hollow spheres.

[0070] 17. The laminate article of any one of embodiment sl4 to 16, wherein the filler is present in an amount of about 20% to 60% by weight of the adhesive.

[0071] 18. The laminate article of any one of embodiments 14 to 17 , wherein the adhesive has an impact peel strength of at least 5 N / mm at a temperature of 40° C, wherein the impact peel strength is measure in accordance with ISO 4587.

[0072] 19. The laminate article of any one of the preceding embodiments, wherein the adhesive is comprised of one or more of an epoxy resin, acrylate adhesive, and polyurethane adhesive.

[0073] 20. The laminate article of embodiment 19, wherein the adhesive is the epoxy resin further comprised of toughener.

[0074] 21. The laminate article of any one of embodiments 14 to 18, wherein the adhesive is a comprised of one or more of a urethane, urea, formaldehyde, epoxy and acrylate.

[0075] 22. The laminate article of embodiment 21, wherein the adhesive is comprised of urea and urethane.

[0076] 23. The laminate article of embodiment 6, wherein the thermoplastic polymer is comprised of one or more of a polyamide, polyimide, polyamideimide, polyester, polyetherester, thermoplastic polyurethane, polyacrylate, polyacrylic acid, polyolefin grafted polyolefin or mixture thereof.

[0077] 24. The laminate article of any one of the preceding embodiments, wherein the laminate article is an assemblage of two or more laminate articles into a lattice structure.

[0078] 25. The laminate article of embodiment 24, wherein the assemblage supports a a mold.

[0079] 26. The laminate of embodiment 24, wherein the mold and laminate article each have a coefficient of thermal expansion and a ratio of mold / laminate coefficient of thermal expansion ratio of % to 2.

[0080] 27. The laminate article of embodiment 24, wherein the mold is comprised of a carbon fiber polymer composite.

[0081] 28. The laminate article of any one of the preceding embodiments wherein the laminate article has a bending strength of at least 500 pounds per square inch.

[0082] 29. A method of forming a laminate article comprising,(i) contacting a unidirectional fiber polymer composite with another unidirectional fiber polymer composite to form an assembled segmented layer having a segmented layer face and the fibers are essentially parallel in the assembled segmented layer,(ii) contacting the face with a bonding layer comprised of an adhesive and fabric, and(iii) curing the adhesive to form the laminate article, wherein the assembled segmented layer is constrained during the contacting and curing to form the laminate article.

[0083] 30. The method of embodiment 29, wherein at least a portion of the contacting or curing is done under pressure.

[0084] 31. The method of embodiment 29 or 30, wherein the constraint is a mold.

[0085] 32. The method of any one of embodiments 29 to 31 adhesive and fabric is a prepreg.

[0086] 33. The method of any one of embodiments 29 to 32, wherein the curing is comprised of applying pressure and heat.

[0087] 34. The method of any one of embodiments 29 to 33 further comprising forming a cap layer on the laminate article.

[0088] 35. The method of embodiment 34, wherein the forming is by twin sheet thermoforming.

[0089] 36. The method of any one of embodiments 29 to 33, wherein there is a plurality of assembled segmented layers and bonding layers interposed and bonding the assembled segmented layers.

[0090] 37. The method of embodiment 36, wherein at least one assembled segmented layer has fibers that are orthogonal to the fibers in another assembled segmented layer.

Claims

CLAIMSWhat is claimed is:

1. A laminate article comprised of a segmented layer comprised of a plurality of unidirectional continuous fiber polymer composite members, the unidirectional continuous fiber polymer composite members are abutted forming a segmented layer face having fibers in each member of the segmented layer being essentially parallel and a bonding layer comprised of an adhesive and a fabric that is adhered to the segmented layer face.

2. The laminate article of claim 1, wherein unidirectional continuous fiber polymer composite members are pultruded unidirectional continuous fiber polymer composites.

3. The laminate article of claim 1, wherein the laminate article is comprised of at least two segmented layers and the continuous fiber direction in at least one segmented layer is essentially parallel to another segmented layer.

4. The laminate article of claim 1, wherein the laminate article is comprised of at least two segmented layers and the fibers in at least one segmented layer are orthogonal to the fibers in another segmented layer.

5. The laminate article of claim 4, wherein laminate article has a cap layer that covers at least a portion of a face of the laminate article.

6. The laminate article of claim 1, wherein the polymer of the unidirectional continuous fiber polymer composite is comprised of one or more of an epoxy, polyurethane or polyurea.

7. The laminate article of claim 1, wherein the fabric is comprised of a fiber that is the same as the fiber of the unidirectional continuous fiber composite.

8. The laminate article of claim 1, wherein the fabric is comprised of one or more of a naturally occurring fiber, metal fiber, inorganic glass fiber, polymer fiber and carbon fiber.

9. The laminate article of claim 8, wherein the fibers are carbon fibers.

10. The laminate article of claim 1, wherein the fabric is woven.

11. The laminate article of claim 1 , wherein the adhesive has an impact peel strength of at least 5 N / mm at a temperature of 40° C, wherein the impact peel strength is measure in accordance with ISO 4587.

12. The laminate article of claim 11, wherein the adhesive has a filler.

13. The laminate article of 11, wherein the adhesive is comprised of one or more of an epoxy resin, acrylate adhesive, and polyurethane adhesive.

14. The laminate article of claim 13, wherein the adhesive is comprised of urea and urethane.

15. The laminate article of claim 1, wherein the laminate article is an assemblage of two or more laminate articles forming a lattice structure.

16. The laminate article of claim 15, wherein the assemblage supports a mold.

17. The laminate of article 16, wherein the mold and laminate article each have a coefficient of thermal expansion and a ratio of mold / laminate coefficient of thermal expansion ratio of to 2.

18. The laminate article of claim 17, wherein the mold is comprised of a carbon fiber polymer composite.

18. The laminate article of claim 1, wherein the laminate article has a bending strength of at least 500 pounds per square inch.

19. A method of forming a laminate article comprising,(i) contacting a unidirectional fiber polymer composite with another unidirectional fiber polymer composite to form an assembled segmented layer having a segmented layer face and the fibers are essentially parallel in the assembled segmented layer,(ii) contacting the face with a bonding layer comprised of an adhesive and fabric, and(iii) curing the adhesive to form the laminate article, wherein the assembled segmented layer is constrained during the contacting and curing to form the laminate article.

20. The method of claim 19, wherein at least a portion of the contacting or curing is done under pressure.

21. The method of claim 19, wherein the constraint is a mold.

22. The method of claim 19, wherein the adhesive and fabric is a prepreg.

23. The method of 19, wherein the curing is comprised of applying pressure and heat.

24. The method of claim 19 further comprising forming a cap layer on the laminate article.

25. The method of claim 24 wherein the forming of the cap palyer is by twin sheet thermoforming.

26. The method of any one of claims 29 to 33, wherein there is a plurality of assembled segmented layers and bonding layers interposed.

27. The method of claim 26, wherein at least one assembled segmented layer has fibers that are orthogonal to the fibers in another assembled segmented layer.

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