Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
  • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
  • B29C70/06—Fibrous reinforcements only
  • B29C70/08—Fibrous reinforcements only comprising combinations of different forms of fibrous reinforcements incorporated in matrix material, forming one or more layers, and with or without non-reinforced layers
  • B29C70/081—Combinations of fibres of continuous or substantial length and short fibres
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/24—Impregnating materials with prepolymers which can be polymerised in situ, e.g. manufacture of prepregs
  • C08J5/241—Impregnating materials with prepolymers which can be polymerised in situ, e.g. manufacture of prepregs using inorganic fibres
  • C08J5/243—Impregnating materials with prepolymers which can be polymerised in situ, e.g. manufacture of prepregs using inorganic fibres using carbon fibres
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
  • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
  • B29C70/06—Fibrous reinforcements only
  • B29C70/10—Fibrous reinforcements only characterised by the structure of fibrous reinforcements, e.g. hollow fibres
  • B29C70/16—Fibrous reinforcements only characterised by the structure of fibrous reinforcements, e.g. hollow fibres using fibres of substantial or continuous length
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/04—Reinforcing macromolecular compounds with loose or coherent fibrous material
  • C08J5/0405—Reinforcing macromolecular compounds with loose or coherent fibrous material with inorganic fibres
  • C08J5/042—Reinforcing macromolecular compounds with loose or coherent fibrous material with inorganic fibres with carbon fibres
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/04—Reinforcing macromolecular compounds with loose or coherent fibrous material
  • C08J5/10—Reinforcing macromolecular compounds with loose or coherent fibrous material characterised by the additives used in the polymer mixture
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
  • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
  • B29C70/06—Fibrous reinforcements only
  • B29C70/10—Fibrous reinforcements only characterised by the structure of fibrous reinforcements, e.g. hollow fibres
  • B29C70/12—Fibrous reinforcements only characterised by the structure of fibrous reinforcements, e.g. hollow fibres using fibres of short length, e.g. in the form of a mat
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2029/00—Use of polyvinylalcohols, polyvinylethers, polyvinylaldehydes, polyvinylketones or polyvinylketals or derivatives thereof as moulding material
  • B29K2029/04—PVOH, i.e. polyvinyl alcohol
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2063/00—Use of EP, i.e. epoxy resins or derivatives thereof, as moulding material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
  • B29K2105/06—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts
  • B29K2105/08—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts of continuous length, e.g. cords, rovings, mats, fabrics, strands or yarns
  • B29K2105/0872—Prepregs
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2363/00—Characterised by the use of epoxy resins; Derivatives of epoxy resins

Definitions

• the present invention relates to a method for making a highly finished surface article of an advanced composite material and the advanced composite material article made thereby.
• the motor vehicle components are conventionally classified based on their surface quality and, accordingly, on the aesthetic requirements they must meet.
• Three motor vehicle classes are usually identified, that is the classes A, B and C.
• the class A is related to the visible motor vehicle parts, such as, for example, motor vehicle bonnets .
• the class B is also related to vehicle visible parts, but the aspect of which is not considered essential, such as, for example, the door opening recess.
• the class C is related to the motor vehicle non-visible parts, such as, for example, the joints of the motor vehicle seats.
• the surface quality is evaluated based on a human observation of images reflected from the motor vehicle body parts, under controlled illuminating conditions .
• the class A surfaces are so designed as to provide an alignment between the bent and tangent lines, so as to give a perfect reflection quality. Moreover, the class A surfaces are free of undesirable waviness patterns and have a continuous bending in each direction.
• the reinforcement fibers may generate visible traces on the part surface, preventing the part from being used for class A finished surfaces.
• a further machining of the molded piece or part a further spreading of a primer, or a pre-smoothing operation, for eliminating possible surface defects or pores .
• the method for making class A composite material parts further comprises one or more additional processing or machining steps performed by very long and complex operations, causing the making cost to greatly increase.
• the aim of the present invention is to provide such a method for making advanced composite material parts having a high surface finishing, which method is specifically designed for making motor vehicle body parts .
• a main object of the invention is to provide such a method adapted to make motor vehicle body parts having both a very high surface finishing and a very high size stability.
• Another object of the present invention is to provide such an article or product, made by the inventive method, having both a very good impact resistance or resilience and a very good stiffness.
• Yet another object of the present invention is to provide such a method allowing to make motor vehicle body parts at a much smaller cost than that of prior making systems and methods.
• a method for making, by molding, a part coupled to two layers, in particular of a motor vehicle body, of an advanced composite material and having a high surface finishing comprising coupling, by an impregnating hot-melt machine, a first layer of a fibrous base material and a second layer of a pre-impregnated coupled composite material, or prepreg, forming the outermost portion of said coupled part, that is that portion contacting the mold in the molding process and which, in a finished condition, has high surface finishing characteristics; said first layer being impregnated by an impregnating resin system identical to and compatible with that impregnating said second layer and being polymerized or cross-linked simultaneously with said second layer; said method comprising moreover the step of operating said impregnating hot-melt machine at an operating speed of 2-4 meters/min; said resin system consisting of a hot- melt epoxy resin forming
• the method according to the present invention is particularly useful for making motor vehicle body parts starting from a composite material, but it can also be used in the nautical, sports and aeronautical fields.
• the method according to the present invention greatly reduces or fully eliminates the visibility of reinforcement fibers on the article surface.
• Figure 1 shows a table wherein temperatures, pressures, heating and cooling ramps of an autoclave cross-linking cycle, according to a first embodiment of the present invention, are shown;
• Figure 2 is a diagram diagrammatically 3 002801
• Figure 3 shows a further table indicating temperatures, pressures, heating and cooling ramps of an autoclave polymerizing or cross-linking cycle of a second embodiment of the present invention.
• Figure 4 is a further diagram diagrammatically showing the operating steps shown in the table of Figure 3.
• the components of a composite material are separated by a well defined separating interface having a substantially zero thickness, each of said components having chemical-physical properties different from one another at a macroscopic and structural level.
• the individual components forming a composite material are herein called “the matrix” and “the reinforcement”.
• the coupling or joining of the above components or materials will provide a solid continuous material, adapted to transmit and redistribute the inner strains due to outer stresses.
• the reinforcement material comprises a dispersed phase, which is variously dispersed through the matrix and is so designed as to provide the composite material with a target stiffness and mechanical strength.
• the composite materials used in the present invention are made of a reinforcement material consisting of a dispersed fibrous phase.
• the fibers of said dispersed fibrous phase comprise solid and resistant bodies of an elongated shape, that is having a longitudinal dimension prevailing with respect to the cross dimension, and providing the composite material with the desired strength and stiffness.
• the reinforcement material may comprise, by way of an example:
• the fibers are joined to form fiber beams, in the form of parallel fiber threads or of twined fibers.
• the reinforcements used for preferred applications according to the present invention comprise the following materials:
• multi-axial reinforcements consisting of overlapped unidirectional reinforcements
• the matrix comprises a homogeneous continuous phase operating as a filling material.
• Such a material is at the start in the form of a viscous fluid, properly filling all the spaces and perfectly adhering to the fibers.
• the matrix is subjected to a solidifying process providing the construction with stability and well defined geometric properties.
• the matrix types used for preferred applications according to the present invention mainly consist of polymeric matrix .
• composite materials such as thermoplastic materials (such as Nylon and ABS) or thermosetting materials (such as epoxy resins) .
• the joining of the resin to the reinforcement may be performed during the component making, by conventional manual impregnating methods, or operating steps preceding the making of the piece.
• the materials included in this second class are defined "preimpregnated” or “prepreg” materials.
• the fibers forming the above materials are impregnated by an industrial process which, besides using a proper fiber amount, arranges the impregnating resins in an even manner.
• the present invention also relates to a coupled preimpregnated (prepreg) material forming the outermost portion of the article to be made, that is that portion contacting the mold during the piece molding process and which, on the finished piece, will have high finishing surface characteristics.
• preg preimpregnated
• the coupling is performed in the prepreg making method, and, accordingly, in impregnating said prepreg, and is related to the conventional support, consisting either of unidirectional, multiaxial fibers or woven fabrics, and a fibrous material layer, consisting either of a non-woven material, a felt material or any materials having similar characteristics.
• said support and coupled layer can also comprise carbon, glass, aramidic fibers or any fibers used for making advanced composite materials.
• the making of said prepreg further comprises a short heating of pre-processed fibers, by heating ovens, so as to provide a first partial cross-linking of the matrix: this operating step provides the product with the reguired compactness while fully eliminating residual air bubbles and allowing the material to be further processed without altering its characteristics.
• non-woven fibers having a fiber length from 6 to 12 mm;
• the fibers are bound by a PVA (polyvinyl alcohol) binder material;
• the chosen material is impregnated by an epoxy resin system, modified by an addition of a proper amount of inert materials such as:
• inert materials provides a covering effect for the resin system with respect to the fabric, while minimizing the fiber surface projection, which would be an unacceptable phenomenon for class A finished surfaces.
• the subject system is compatible with other epoxy systems forming the remaining part of the article of manufacture.
• the chosen . material allows to perform a standardized crosslinking operating cycle, for example in an autoclave, a vacuum bag and a hot press.
• the finished surface of the part thus made has a very good surface quality, free of white spots, even after a processing in a water bath (two hours in boiling water or 30 days at room temperature) .
• class A motor vehicle body parts made of an advanced composite material directly from the mold, provides further great advantages, for example a great reduction of manual machining time during the part layering and finishing operating steps.
• the coupling according to the present invention provides a direct connection to the prepreg used, while greatly reducing the machining time.
• the material and process must be accurately designed to provide the desired high surface finishing degree for the overall lifetime duration of the motor vehicle.
• the use of the above mentioned advanced composite material owing to the optimization of its properties and making process, allows to further achieve a design flexibility which cannot be achieved in prior approaches using metal materials.
• the advantages achieved comprise an optimization of the mechanical stress resistance, an optimum balancing of the stiffness and weight ratio, and an improved freedom in designing the motor vehicle body parts.
• the above mentioned polymerizing/crosslinking cycle is a process in which the resin of the prepreg changes from a liquid to a solid status by applying heat .
• Standard processing methods provide to perform the crosslinking cycle in an autoclave, a hot press or a vacuum bag.
• the overall part, made of prepreg, and the related mold must be held at the crosslinking temperature for the time required by any resin system.
• the heating speed is a measurement of the time required for the part being made to achieve the polymerizing or crosslinking temperature.
• This operating step is controlled by different parameters, such as, for example:
• the cooling speed or rate is so controlled as to prevent any sudden temperature changes from causing a mechanical stress within the composite material part. .
• the visual examination evaluates the aspect of the part under test: the requirements to be met provide that the examined part surface be a continuous and even one, free of surface and aesthetic defects.
• Each cycle comprises:
• a coupled woven and non-woven carbon material and impregnating by a modified epoxy resin A coupled woven and non-woven carbon material and impregnating by a modified epoxy resin.
• a carbon woven or fabric material a 2x2 twill weave, with a weight from 180 to 400 g/m 2 (A) ;
• a carbon non-woven material a weight from 20 to 50 g/m 2 (B) ;
• Resin contents from 45% to 65% of the end weight of the overall coupled impregnated material.
• a + B of this example is carried out by two different consecutive process stages, with an impregnating hot melt machine speed from 2 to 4 meters/min:
• the amount of resin deposited on the support corresponds to an amount from 40% to 50% of the end weight of the impregnated fabric; the cylinder pressure being set from 2 to 6 bars;
• a possible laminating sequence suitable for using the solution disclosed in the previous example comprises:
• the method according to this exemplary embodiment comprises to make a motor vehicle body part as schematically disclosed hereinbelow, starting from the outside of the finished part, and accordingly from the mold surface:
• UD Unidirectional reinforcement
• carbon non-woven coupled materials an impregnating by a modified epoxy resin:
• an unidirectional carbon reinforcement material with a weight from 120 to 400 g/m 2 (C) ;
• a carbon non-woven material with a weight from 15 to 70 g/m 2 (D) ;
• Resin contents from 40% to 60% of the end weight of the overall coupled impregnated material. Impregnating and coupling process
• the impregnating process for impregnating the coupled material C + B of this Example is carried out in two different following process stages, with a hot melting impregnating machine speed from 2 to 4 m/min:
• the amount of resin deposited on the support corresponds to an amount from 30% to 40% of the end weight of the impregnated reinforcement material
• the process comprises to make a motor vehicle body part as hereinbelow schematically disclosed, starting from the outside of the finished part, and accordingly from the mould surface:
• the materials used, as well as the contingent size and shapes can be any, depending on requirements.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Polymers & Plastics (AREA)
• Manufacturing & Machinery (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Composite Materials (AREA)
• Mechanical Engineering (AREA)
• Textile Engineering (AREA)
• Moulding By Coating Moulds (AREA)
• Reinforced Plastic Materials (AREA)
• Casting Or Compression Moulding Of Plastics Or The Like (AREA)
• Laminated Bodies (AREA)
• Transition And Organic Metals Composition Catalysts For Addition Polymerization (AREA)

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• 2013
  • 2013-10-04 IT IT001648A patent/ITMI20131648A1/it unknown
  • 2013-12-16 WO PCT/IB2013/002801 patent/WO2015049550A1/en not_active Ceased
  • 2013-12-16 EP EP13828926.9A patent/EP3052302A1/en not_active Withdrawn
  • 2013-12-16 JP JP2016519389A patent/JP6241690B2/ja not_active Expired - Fee Related

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