Epoxy resins have been in use in U.S. industry for over 40 years. Phenolic and amino resins are another group of PMC resins. Design allowable   A limiting value for a material property that can be used to design a structural or mechanical system to a specified level of success with 95% statistical confidence. Structural bond   A bond joining load-bearing components of an assembly. Bias fabric   A fabric in which warp and fill fibers are at an angle to the length. TTY Carbon fibers commonly in use are also greater than six micrometers in diameter, making them unlikely to be respirable. The ‘Hazard classification and labelling’ section shows the hazards of a substance based on the standardised system of statements and pictograms established under the CLP (Classification Labelling and Packaging) Regulation. Phenolic resin processing (uses of downstream users of phenolic resins) * Examples for processing: Use as an intermediate, use as a monomer etc., use as a solvent, use for the manufacturing of resins. Pp 64-67. Nondestructive testing (NDT) is broadly considered synonymous with NDI. Unidirectional   Refers to fibers that are oriented in the same direction, such as unidirectional fabric, tape, or laminate, often called UD. Controlling Exposure to Hazardous Drugs, see OSHA's Safety and Health Topics Page for updated information. However, due to the same properties epoxy products are a notorious cause of allergic skin disease among workers. Potential worker exposure obviously will also vary widely, depending on the size and type of process being used. Wet layup   The application of resin to dry reinforcement in the mold. Engineered Materials Handbook, Vol. S-glass   Structural glass; a magnesia/alumina/silicate glass reinforcement designed to provide very high tensile strength. Much of the dust generated in these processes can be very fine and should be considered respirable. Filaments   Individual fibers of indefinite length used in tows, yarns, or roving. Since epoxies are relatively high molecular-weight compounds, the potential for respiratory exposure is fairly low. Isotropic Having uniform properties in all directions independent of the direction of load application. Interlaminar shear   The shearing force tending to produce displacement between two laminae along the plane of their interface; usually the weakest element of a composite. Stiffness   The relationship of load to deformation for a particular material. Resin   A material, generally a polymer, that has an indefinite and often high molecular weight and a softening or melting range and exhibits a tendency to flow when it is subjected to stress. Polymer   A very large molecule formed by combining a large number of smaller molecules, called monomers, in a regular pattern. Unbond   Area of a bonded surface in which bonding of adherends has failed to occur, or where two prepreg layers of a composite fail to adhere to each other; also denotes areas where bonding is deliberately prevented to simulate a defective bond. Contact with the liquid may cause defatting of the skin and dermatitis. Interface   The surface between two different materials: in fibers, the area at which the glass and sizing meet; in a laminate, the area at which the reinforcement and the laminating resin meet. Once cured, the part cannot be changed or reformed, except for finishing. Cure   To change the physical properties of a material irreversibly by chemical reaction via heat and catalysts, alone or in combination, with or without pressure. www.zortrax.com | 2 / 13 SAFETY DATA SHEET Resin BASIC 2.2. The coated strands are then passed through a heated die where curing occurs. Resin starved   Localized area lacking sufficient resin for wetout of the fibers. Polyurethanes are another group of resins used in advanced composite processes. Draft angle   A mandrel's taper or angle for ease of part removal. Grinding, routing and sanding are frequently used methods in both processes. Buckling (composite)   A failure usually characterized by fiber deflection rather than breaking because of compressive action. Continuous filament   An individual, small-diameter reinforcement that is flexible and indefinite in length. The Department of Labor does not endorse, takes no responsibility for, and exercises no control over the linked organization or its views, or contents, nor does it vouch for the accuracy or accessibility of the information contained on the destination server. These controls can be found in: Work practices, as distinguished from engineering controls, involve the way a task is performed. Polymerization   A chemical reaction in which the molecules of monomers are linked together to form polymers. This sector of the composites industry is characterized by the use of expensive, high-performance resin systems and high-strength, high-stiffness fiber reinforcement. Core   The central component of a sandwich construction to which the sandwich faces or skins are attached; also, part of a complex mold that forms undercut parts. For problems with accessibility in using figures and illustrations in this document, please contact the Office of Science and Technology Assessment at (202) 693-2095. Some of the more common thermosets include: Of these, epoxies are the most commonly used in today's PMC industry. the chemical 2 / 10 Material name: Asplit Phenolic Resin 5469 Version #: 08 Revision date: 04-24-2019 Issue date: 04-22-2015 SDS US Fatigue   The failure of a material's mechanical properties as a result of repeated stress. Compressive strength   A material's ability to resist a force that tends to crush or buckle; maximum compressive load a specimen sustains divided by the specimen's original cross-sectional area. Many manufacturers have replaced the ketones with the above hydrocarbon solvents to reduce the risk of flammability. These aromatic amines are considered to be only slightly irritating to the skin. Glass fibers break only into shorter fragments of the same diameter. Hazard classification & labelling Hazard classification and labelling. Nonwoven roving   A reinforcement composed of continuous rovings loosely gathered together. Resin formulation consists of mixing epoxy or other resins with other ingredients to achieve desired performance parameters. Res., vol. Isolation (e.g., isolated storage, separate process areas, enclosures, closed systems) and local exhaust ventilation are the primary engineering controls found in advanced composites processes. Solvents may serve three purposes: Diagrams of the major processes used in the advanced composites industry are provided in Section A of this chapter. Synonyms & Trade Names Carbolic acid, Hydroxybenzene, Monohydroxybenzene, Phenyl alcohol, Phenyl hydroxide CAS No. Hand layup   A fabrication method in which reinforcement layers, preimpregnated or coated afterwards, are placed in a mold by hand, then cured to the formed shape. Polyacrylonitrile (PAN)   A product used as a base material in the manufacture of certain carbon fibers. Fumes from burning material may irritate eyes, nose and or … The second of the essential ingredients of an advanced composite system is the curing agent or hardener. Carbon fibers may be coated with a material to improve handling, known generically as sizing. Visual disturbances may also occur. High molecular weight is generally associated with decreased volatility. Many of the parts made in PMC processes require some machining and/or finishing work. Thermosetting resins predominate today, while thermoplastics have only a minor role in advanced composites manufacture. The aromatic amines may permeate many of the commonly used protective gloves and thus may be particularly difficult to protect against. Braiding   Weaving fibers into a tubular shape. Contact molding   A technique in which reinforcement and resin are placed in a mold, with cure taking place at room temperature with a catalyst/promoter system, or in a heated oven. Fiber reinforcement fabric or mat is laid by hand into a mold and resin mixture is poured or injected into the mold cavity. Doubler   Localized area of extra layers of reinforcement, usually to provide stiffness or strength for fastening or other abrupt load transfers. Volatiles   Materials in a sizing or a resin formulation that can be vaporized at room or slightly elevated temperature. Thermoset   A plastic material that is capable of being cured by heat or catalyst into an infusible and insoluble material. Sizing   A compound that binds together and stiffens warp yarn to provide resistance to abrasion during weaving; normally removed and replaced with finish before matrix application. Res., vol. Phenol formaldehyde resins (PF) or phenolic resins are synthetic polymers obtained by the reaction of phenol or substituted phenol with formaldehyde.Used as the basis for Bakelite, PFs were the first commercial synthetic resins (plastics).They have been widely used for the production of molded products including billiard balls, laboratory countertops, and as coatings and adhesives. www.OSHA.gov, Occupational Safety and Health Administration These alcohols do not usually present serious hazards in the industrial setting. In the filament wet winding process, continuous fiber reinforcement materials are drawn through a container of resin mixture (Figure III:1-3) and formed onto a rotating mandrel to achieve the desired shape. Composite products range from skateboards to components of the space shuttle. Most of the fibers in use are considered to be in the nonrespirable range. The process may consist of several steps including cutting out of the damaged material, depainting of the surface to be repaired, patching and sanding of the damaged area, and repainting of the repaired area. Structural adhesive   An adhesive used for transferring loads between adherends. Tensile strength   The maximum tensile stress sustained by a plastic specimen before it fails in a tension test. Bag molding   A technique in which the composite material is placed in a rigid mold and covered with a flexible bag, with pressure applied by vacuum, autoclave, press, or by inflating the bag. Individual Protection Measures, Such as Personal Protective Equipment The basic epoxy compounds most commonly used in industry are the reaction product of epichlorohydrin and bisphenol-A. The tape is applied across the surface of a mold in multiple layers by the preprogrammed robot (Figure III:1-5). While aerospace is the predominant market for advanced composites today, the industrial and automotive markets will increasingly see the use of advanced composites toward the year 2000. H317 May cause … These include: Some of the lower-boiling alcohols are sometimes used in composites manufacture. Continuous-filament yarn   Yarn that is formed by twisting two or more continuous filaments into a single continuous strand. The skin staining has been attributed to MDA; dermal absorption is approximately 2% per hour. A prepreg product is laid down and formed to the desired shape (Figure III:1-4). Young's modulus   The ratio of normal stress to the corresponding strain for tensile or compressive stresses less than the proportional limit of the material. Specific gravity   The density (mass per unit volume) of a material divided by that of water at a standard temperature. The composites industry in the United States includes three manufacturing areas: Polymers, metals, and ceramics. These fibers differ from the wool type in that they are die-drawn rather than spun. Fiber orientation   The fiber alignment in a nonwoven or a mat laminate in which most of the fibers are in the same direction, thereby affording higher strength in that direction. Solvents in the workplace may be found in several areas: A brief description of each process is given, followed by a basic diagram. Storage life   The amount of time a material can be stored and remain suitable for use. The dusts of high-melting solids like most anhydride curing agents are severe eye and skin irritants. Exposure to the high-melting solids like trimellitic anhydride and tetraphthalic anhydride can cause respiratory sensitization. Of these, epoxy systems currently dominate the advanced composite industry. In this process, the prepreg tape material is fed through an automated tape application machine (robot). Thermosets are subdivided into several resin systems including epoxies, phenolics, polyurethanes, and polyimides. Mandrel. Several advanced composite processes involve some worker contact with the resin mixture. Several of the composites manufacturing processes are common to both segments. Hazards of Isocyanates (TDI, MDI, HDI) In Resins, Coatings and Paints. Ingestion: Essentially non-irritating to cause injury. The industrial composites industry has been in place for over 40 years in the U.S. Amide hardeners generally have only a slight irritant effect. 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