Background Electronic packaging glue is used to package electronic devices. It is a type of electronic glue or adhesive that performs sealing, encapsulation or potting. After being packaged with electronic packaging glue, it can play the role of waterproof, moisture-proof, shockproof, dustproof, corrosion-resistant, heat dissipation, confidentiality, etc. Therefore, electronic packaging glue needs to have the characteristics of high and low temperature resistance, high dielectric strength, good insulation, and environmental safety.   Why choose epoxy resin? With the continuous development of large-scale integrated circuits and the miniaturization of electronic components, the heat dissipation of electronic components has become a key issue affecting their service life. There is an urgent need for high thermal conductivity adhesives with good heat dissipation performance as packaging materials. Epoxy resin has excellent heat resistance, electrical insulation, adhesion, dielectric properties, mechanical properties, small shrinkage, chemical resistance, and good processability and operability after adding curing agent. Therefore, currently, many semiconductor devices abroad are encapsulated with epoxy resin.   The development of epoxy resin With the increasing calls for environmental protection and the increasing performance requirements of the integrated circuit industry for electronic packaging materials, higher requirements have been put forward for epoxy resins. In addition to high purity, low stress, thermal shock resistance and low water absorption are also issues that need to be solved urgently. In response to problems such as high temperature resistance and low water absorption, domestic and foreign research has started from molecular structure design, focusing mainly on blending modification and the synthesis of new epoxy resins. On the one hand, biphenyl, naphthalene, sulfone and other groups and fluorine elements are introduced into the epoxy skeleton to improve the moisture and heat resistance of the material after curing. On the other hand, by adding several types of representative curing agents, the curing kinetics, glass transition temperature, thermal decomposition temperature and water absorption of the cured product are studied, in an effort to prepare high-performance epoxy resins for electronic packaging materials.   Introduction of several special epoxy resins for electronic packaging 1. Biphenyl type epoxy resin The tetramethyl biphenyl diphenol epoxy resin (its structure is shown in the figure) synthesized by the two-step method exhibits high heat resistance, good mechanical properties and low water absorption after being cured by DDM and DDS. The introduction of the biphenyl structure greatly improves the heat resistance and moisture resistance, which is conducive to its application in the field of electronic packaging materials.   2. Silicone epoxy resin Another research hotspot in the field of electronic packaging is the introduction of silicone segments, which can not only improve heat resistance, but also enhance toughness after epoxy curing. Silicon-containing polymers have good flame retardant properties. The low surface energy of silicon-containing groups causes them to migrate to the resin surface to form a heat-resistant protective layer, thereby avoiding further thermal degradation of the polymer. Some researchers have used chlorine-terminated organosiloxane polymers to modify bisphenol A epoxy resins, generating Si-O bonds through the reaction of terminal chlorine with the hydroxyl groups on the epoxy chain. The structural formula is shown in the figure below.   This method increases the cross-linking density of the cured resin without consuming epoxy groups, which not only toughens the resin but also improves its heat resistance and impact resistance.     3. Fluorinated epoxy resin Fluorine-containing polymers have many unique properties. Fluorine has the greatest electronegativity, the interaction between electrons and nuclei is strong, the bond energy between chemical bonds with other atoms is large, and the refractive index is low. Fluorine-containing polymers have excellent heat resistance, oxidation resistance and chemical resistance. Fluorinated epoxy resin has the properties of dustproof and self-cleaning, heat resistance, wear resistance, corrosion resistance, etc. It can also improve the solubility of epoxy resin. At the same time, it has excellent flame retardancy, becoming a new material in the field of electronic packaging.   The fluorinated epoxy resin synthesized in the laboratory is liquid at room temperature and has extremely low surface tension. After curing with silanamine at room temperature or fluorine anhydride, an epoxy resin with excellent strength, durability, low surface activity, high Tg and high ultimate stability can be obtained. The synthesis steps are:   4. Containing dicyclopentadiene epoxy resin Dicyclopentadiene o-cresol resin can be synthesized by reaction, the reaction formula is shown in the figure below. The resin is cured with methyl hexahydrophthalic anhydride and polyamide curing agent, and the Tg of the cured product is 141°C and 168°C respectively. There is a new type of low-dielectric dicyclopentadiene epoxy resin (see figure below) whose performance is comparable to that of commercial bisphenol A epoxy resin, with a 5% heat loss of more than 382°C, a glass transition temperature of 140-188°C, and a water absorption rate (100°C, 24h) of only 0.9-1.1%.     5. Naphthalene-containing epoxy resin Some researchers have synthesized a new type of naphthalene-containing phenolic epoxy resin, the reaction formula of which is shown in the figure below. Its DDS cured product exhibits excellent heat resistance, with a Tg of 262°C and a 5% thermal weight loss of 376°C. Synthesis of Bisphenol A-Naphthaldehyde Novolac Epoxy Resin     6. Alicyclic Epoxy resin  The characteristics of alicyclic epoxy resins are: high purity, low viscosity, good operability, high heat resistance, small shrinkage, stable electrical properties and good weather resistance. They are particularly suitable for high-performance electronic packaging materials with low viscosity, high heat resistance, low water absorption and excellent electrical properties. They are extremely promising electronic packaging materials.   The figure below shows the reaction process of a new type of heat-resistant liquid alicyclic epoxy compound. It can be obtained by etherifying alicyclic olefin diols with halogenated hydrocarbons to form alicyclic triolefin ethers, which are then epoxidized. 7. Blending modified epoxy resin Blending is an important method to effectively improve material properties. In an epoxy matrix, adding another or several epoxy resins can improve one or several specific properties of the matrix material, thereby obtaining a new material with better comprehensive performance. In epoxy molding compounds, blending can achieve the goal of reducing costs and improving performance and processing performance.   In future production research, in order to enable epoxy resins to be fully used in the domestic electronic packaging industry, improving the preparation process technology, exploring the curing system of high-performance epoxy resins resistant to moisture and heat and medium-temperature moisture and heat-resistant epoxy resins, and preparing new epoxy resin modified additives are the development directions of this research field. Nanjing Yolatech provides all kinds of high purity and low chlorine epoxy resins and special epoxy resin, including Bisphenol A epoxy resin, Bisphenol F epoxy resin, Phenolic epoxy resin, Brominated epoxy resin, DOPO modified phenolic epoxy resin, MDI modified epoxy resin, DCPD epoxy resin, Multifunctional epoxy resin, Crystalline epoxy resin, HBPA epoxy resin and so on. And we also could provide all kinds of curing agents or hardeners and diluents for epoxy resin application. Welcome new and old customers to inquire, we will provide you with the best service.    

There are many choices for raw materials of composite materials, including resin, fiber and core material, and each material has its own unique properties such as strength, stiffness, toughness and thermal stability, and the cost and output are also different. However, the final performance of composite materials is not only related to the resin matrix and fiber (and the core material in the sandwich structure), but also closely related to the design method and manufacturing process of the materials in the structure. Ten common composite molding processes   1. Spraying: A molding process in which the chopped fiber reinforcement material and the resin system are sprayed into the mold at the same time and then cured under normal pressure to form a thermosetting composite product. Typical applications: simple fences, low-load structural panels, such as convertible bodies, truck fairings, bathtubs and small boats.   2. Hand lay-up: The resin is manually impregnated into the fibers, which can be woven, braided, stitched or bonded. Hand lay-up is usually done with a roller or brush, and then the resin is squeezed into the fibers with a glue roller. The laminate is cured under normal pressure. Typical applications: standard wind turbine blades, mass-produced boats, architectural models.   3. Vacuum bag process: The vacuum bag process is an extension of the above-mentioned hand lay-up process, that is, a layer of plastic film is sealed on the mold to evacuate the hand-laid laminate, and an atmospheric pressure is applied to the laminate to achieve the effect of exhaust and compaction to improve the quality of the composite material. Typical applications: large-sized yachts, racing car parts, and bonding of core materials during shipbuilding.   4. Winding: Winding is basically used to manufacture hollow, round or oval structures such as pipes and troughs. The fiber bundle is impregnated with resin and wound on the mandrel in various directions. The process is controlled by the winding machine and the mandrel speed. Typical applications: chemical storage tanks and delivery pipes, cylinders, firefighter breathing tanks.   5. Pultrusion: The fiber bundle drawn from the spool rack is dipped in resin and passed through a heating plate, where the resin is impregnated into the fiber and the resin content is controlled, and the material is finally cured into the required shape; this fixed shape cured product is mechanically cut into different lengths. The fiber can also enter the hot plate in a direction other than 0 degrees. Pultrusion is a continuous production process, and the cross-section of the product usually has a fixed shape, allowing for slight changes. The pre-impregnated material that passes through the hot plate is fixed and laid into the mold for immediate curing. Although the continuity of this process is poor, the cross-sectional shape can be changed. Typical applications: beams and trusses of house structures, bridges, ladders and fences.   6. Resin transfer molding process: Dry fibers are spread in the lower mold, and pressure can be applied in advance to make the fibers fit the mold shape as much as possible and bonded; then, the upper mold is fixed to the lower mold to form a cavity, and then the resin is injected into the cavity. Usually, vacuum-assisted resin injection and fiber impregnation are used, namely vacuum-assisted resin injection (VARI). Once the fiber impregnation is completed, the resin introduction valve is closed, and the composite material is cured. Resin injection and curing can be performed at room temperature or under heating conditions. Typical applications: small and complex space shuttle and automotive parts, train seats.   7. Other infusion processes: Lay the dry fiber in a similar way to the RTM process, and then lay the peeling cloth and guide net. After the layering is completed, it is completely sealed with a vacuum bag. When the vacuum degree reaches a certain requirement, the resin is introduced into the entire layer structure. The distribution of the resin in the laminate is achieved by guiding the resin flow through the guide net, and finally the dry fiber is completely impregnated from top to bottom. Typical applications: trial production of small boats, train and truck body panels, wind turbine blades.   8. Prepreg-Autoclave Process: The fiber or fiber cloth is pre-impregnated with a resin containing a catalyst by the material manufacturer, and the manufacturing method is high temperature and high pressure method or solvent dissolution method. The catalyst is latent at room temperature, which makes the material effective for several weeks or months at room temperature. Refrigerated conditions can extend its shelf life. The prepreg can be laid into the mold surface by hand or machine, and then covered with a vacuum bag and heated to 120-180°C. After heating, the resin can flow again and finally solidify. The material can be subjected to additional pressure in an autoclave, usually up to 5 atmospheres. Typical applications: Space shuttle structures (such as wings and tails), Formula 1 racing cars.   9. Prepreg - Non-autoclave process: The manufacturing process of low temperature curing prepreg is exactly the same as that of autoclave prepreg, except that the chemical properties of the resin allow it to be cured at 60-120°C. For low temperature 60°C curing, the working time of the material is only one week; for high temperature catalyst (>80°C), the working time can reach several months. The fluidity of the resin system allows the use of vacuum bag curing only, avoiding the use of autoclaves. Typical applications: high performance wind turbine blades, large racing boats and yachts, rescue aircraft, train components.   10. Semi-preg SPRINT/beam prepreg SparPreg non-autoclave process: It is difficult to remove bubbles between layers or overlapping layers during the curing process when using prepreg in thicker structures (>3mm). To overcome this difficulty, pre-vacuuming was introduced into the lamination process, but it significantly increased the process time. Semi-preg SPRINT consists of a sandwich structure with two layers of dry fibers and a layer of resin film. After the material is laid into the mold, the vacuum pump can completely drain the air in it before the resin heats up and softens and wets the fibers and then cures. Beam prepreg SparPreg is an improved prepreg that can easily remove bubbles from between the two bonded layers of material when cured under vacuum conditions. Typical applications: high-performance wind turbine blades, large racing boats and yachts, rescue aircraft.   Our company Nanjing Yolatech can produce a variety of epoxy resins for composite materials. Pls feel free to contact for ir. We will serve you wholeheartedly!