Composite most significant feature is its can design, composite materials, the physical and chemical properties of materials can be accessed through the selection and matching components, and interface control means and other materials designed to achieve, to meet the equipment requirements. Therefore, the choice of raw materials is critical, rational selection of materials, composite materials, also known as design. FRP raw materials include: resin systems, reinforced materials, auxiliary. Selection of raw materials should be considered in the composition and concentration of corrosive media, the use of pressure, temperature and other conditions, as well as environmental factors and field construction conditions and other factors. At the same time the technical indicators should meet the standards or requirements. Acceptance should be tested with a certificate of quality indicators or the corresponding information, if necessary, should be re-inspection or testing. Materials design principles are as follows: (1) process of the selected material system, the process should be suitable for molding method to be adopted; (2) the reliability of the selected material system, sure, as far as possible selection has been finalized, and into mass production, stable quality products; (3) the applicability of the mechanical properties of materials to meet the structural strength and stiffness, resistance to environmental performance of materials used to ensure that the structure can work environment; (4) economic performance in meeting the requirements of the structure under the premise of reducing costs as much as possible. Section I, the choice of the matrix resin Resin, glass steel substrate material, its role is to transfer load, and to load balance, the performance of the matrix material, such as corrosion resistance, heat resistance, directly determines the performance of fiberglass. Commonly used resins include: unsaturated polyester resin, epoxy resin, phenolic resin three categories, including unsaturated polyester resins most widely used. FRP products as chemical resistance, temperature resistance, aging resistance, depending on the resin matrix, so the resin system should pay special attention in the selection. The choice of the matrix resin can be divided into inner layer resin layer of resin selection and structure of the choice of two categories. 1, lined with resin selection Overall, the choice of resin depends lined vessel pressure rating, corrosion medium, the medium temperature factors in these areas. First, direct contact with the media lined with resin, the length of the container's design life depends largely on the corrosion resistance of the resin liner. Secondly, the pressure of the container the higher level requirements lined higher resin elongation. In this software, we will use the experience of previous successful and the data provided by resin production plant built in the database, for reference. 2, the structure layer resin selection The selection of the structure layer of resin to consider its mechanical properties, heat resistance, because the structure of layer structure of resin is mainly responsible for enhanced functionality, not in direct contact with the media, but the medium temperature must be considered. Therefore, the main consideration of their mechanical properties, heat resistance. The choice of the structure layer of resin may refer to the data provided by the manufacturer of the resin. Section II, the choice of fiber-reinforced materials As a reinforcing material is glass fiber and fabrics bearing the main components of steel materials, the strength and stiffness of FRP has a direct impact. Wound with reinforcing materials commonly used include: glass fiber, mainly all kinds of roving, surface mat, knitted blankets, woven roving band, high-strength fiber yarn. To meet the process requirements, the glass fiber rovings should have the following characteristics: (1) chemical resistance (2) process of the resin with good compatibility; (3) reliability of the line density should be guaranteed to drape and small. Alkali E-glass fiber and glass fiber: E-glass fiber for water, high chemical stability and alkali media, good electrical properties, aging properties, suitable for contact with the water products and electrical insulation products, its drawback is easily dilute inorganic acid erosion. Acid-alkali glass fiber performance is very good and the prices cheaper than E-glass fiber. A twist fiber and untwisted fiber: untwisted fiber of the yarn tension between the uniform, lint, and constantly head, as with good, good infiltration of resin, the glass reinforced plastic strength is higher than a twisted fiber. Surface felt and knitted carpets: the first application of the surface of carpet to make the surface smooth, rich and flexible resin layer to reduce friction, improve wear resistance, corrosion resistance, water resistance, aging resistance and impact resistance, is the production of glass fiber reinforced plastic in corrosion-resistant layer of lining material of choice. Non-knitted carpet binder, saturated fast, simple process, provided in a given direction, intensity and improve the corrosion layer thickness and good surface smoothness. Glass mat products commonly used in the winding resin-rich layers, including inner and outer surface, which are used for dry winding, resin impregnated dry soon felt not directly tied to the core coated with a resin mold, and then brush A tool like resin coating on the mats, the general felt chopped strand mat and continuous, winding process of glass fiber mat requirements for: (1) mats are better permeable (2) The defoaming ability is better. Organic fiber and polyester fabrics: organic process of fiber and polyester fabric is worse than glass fibers, but in the media, especially hydrofluoric acid, fluoride glass fibers in the media do not apply, you must use organic fibers and polyester cloth. The software is the choice of the fiber can refer to fiber data sheets. Accessories Section To cure the resin according to process requirements, and improved physical and chemical properties of the resin or the curing of certain properties such as flame-retardant products, antistatic, wear-resistant properties, is usually added in the resin formulation of certain additives such as curing agent, initiator, promoting agents, flame retardants, mold release agents, low-shrinkage agent. Ⅰ, curing agent Curing agent, also known as initiator, it can make resin curing resin formulations is an integral part of, and have a dramatic effect on the resin, mixed with different curing systems, even if the same kind of resin, used in different environments, curing agents are not the same amount added, before being used adequately tested to determine the formula before the official use. FRP used in unsaturated polyester resins, vinyl ester resin dissolved in vinyl monomers, copolymerization of them is to decompose the initiator to trigger free radicals produced, there are two commonly used initiator, organic peroxides and azo compounds. Characteristics of the curing agent used four indicators to measure (1), reactive oxygen Peroxidase activity refers to the-O-O-the percentage content of the higher content under the same conditions from the decomposition of the more free radicals. (2), critical temperature refers to the thermal decomposition of peroxides to form free radical activity has caused the minimum required temperature. (3), the initiator half at a certain temperature the time required for decomposition, commonly used to evaluate the activity of peroxidase. (4), the activation energy means the energy required for peroxide generated free radicals. The choice of curing agent to consider the following factors (1) Resin activity And resin curing agent selected the reaction phase-matching, resin and strong reaction, the choice of higher activity of initiator, reactive resin and weak initiator selected so as not to lower the activity of free radicals to produce faster, to cure the lack of late initiator. (2) for period Preparation of a good glue, to ensure the effective impregnated reinforcing material, the glue of the storage time for different formulations of the applicable period is different. (3) the molding temperature By forming the product temperature can be divided into low, medium temperature, high temperature curing of three types, you must select the appropriate temperature range are in the oxide, winding temperature curing molding method in the context of the curing cycle :30-60MIN, application of 2-3D above. (4) curing rate The curing rate and the initiator of the activity, adding volume and molding temperature, initiator dosage of 1% -2% general, the molding temperature to determine, we can understand the initiator of the relationship between activity and the curing time to achieve the heat peak temperature to calculate the cure time. (5) the influence of other additives Initiator in the selection must be considered filler, pigments and other additives on the curing process of some fillers play a catalytic role, will reduce the storage period, and some will be delayed from the arrest in the storage period. In particular, paint a great impact on the initiator, such as carbon black of the benzoic acid tert-butyl peroxide initiator of the resin, storage of only 3H, reduced to the extent can not be used. Ⅱ, accelerator Accelerator curing unsaturated polyester resins currently used for organic peroxides in the critical temperature of 60 degrees above the temperature required for curing at room temperature, these can not meet the requirements for organic peroxides must try to make the critical peroxide lower the temperature, when the organic peroxide under the action of the tertiary amine, can generate free radicals at lower temperatures. Choose promoter activity should be selected well, with less, faster gel time. Exothermic peak due, less toxic accelerator.

Previous: Surface treatment of glass molds
Next： FRP composite materials industry interactive development of upstream and downs