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!

  Background Epoxy resin is a very important thermosetting resin because there are many epoxy groups in pure epoxy resin. Therefore, the chemical cross-linking density of the cured structure is high, the molecular chain flexibility is low, and the internal stress is large, resulting in the epoxy cured material being more brittle and having poor impact resistance and fatigue resistance durability.So the application and development of epoxy resin in high-tech fields with durability and reliability requirements are limited. Therefore, it is necessary to toughen and modify epoxy resin while maintaining its excellent properties.   Toughening modification methods 1. Rubber elastomer toughened epoxy resin Rubber elastomers are the earliest and most widely used tougheners. Rubber elastomers used for toughening epoxy resins are usually reactive liquid polymers (RLP), that is, the end or side groups have active functional groups (such as -COOH, -OH, -NH2, etc.), which can chemically react with epoxy groups.  Factors that determine the toughening effect of rubber elastomer:a.The solubility of rubber molecules in uncured EP. b. Whether rubber molecules can precipitate during the curing process of epoxy gel and be evenly dispersed in the ring with appropriate particle size and ideal form. in oxygen resin. Currently commonly used RLP rubbers and elastomers include amine-terminated nitrile rubber (ATBN), epoxy-terminated nitrile rubber (ETBN), hydroxyl-terminated nitrile rubber (HTBN), carboxyl-terminated nitrile rubber (CTBN), polyester Sulfur rubber (PSR), PUR and silicone rubber (SR), etc. Among them, CTBN contains very polar nitrile groups (-CN) and has good molecular flexibility. Its toughened EP system forms a "sea-island" microscopic phase separation structure that helps improve the toughness of composite materials. 2. Core-shell polymer toughened epoxy resin Core/shell structure polymer (CSP) toughened epoxy resin technology is used. CSP particles are enriched with different material components inside and outside, resulting in their core and shell having different functions. Compared with the traditional EP/RLP system, due to the good flocculation of the CSP shell, it is incompatible with EP after blending and can form a complete "sea-island" phase separation structure after solidification. By controlling the core-shell material components and particle size, which can significantly improve the toughness of EP. 3. Thermoplastic resin toughened epoxy resin Due to the low molecular weight of rubber elastomers, their introduction into EP will reduce the strength, modulus and heat resistance of the cured product. In order to solve these problems, researchers have developed high toughness, high strength and high heat resistance properties. The TP toughening EP approach can significantly improve EP toughness. The commonly used TPs include polysulfone (PSF), polyethersulfone (PES), polyetherketone (PEK), polyetheretherketone (PEEK), polyetherimide (PEI), polyphenylene ether (PPO), etc. 4. Thermotropic liquid crystal polymer (TLCP) toughened epoxy resin Thermotropic liquid crystal polymer (TLCP) is a type of TP with special properties. Its molecular structure contains a certain amount of flexible segments and a large number of mesogenic rigid units (methylstyrenes, esters, biphenyl, etc.), which exhibits high strength and high Excellent mechanical properties such as modulus and self-reinforcement as well as better heat resistance. Liquid crystal epoxy resin (LCEP) has the advantages of both EP and liquid crystal, and has good compatibility with EP and can be used to toughen epoxy resin. 5. Polymer interpenetrating network structure (IPN) toughened epoxy resin IPN not only improves the impact strength and toughness of composites, but also maintains or even improves their tensile strength and heat resistance. This is because unlike mechanical blends, the polymer component materials in IPN are entangled and penetrated at the molecular segment level, thus showing "forced inclusion" and "synergistic effects" 6. Hyperbranched polymer (HBP) toughened epoxy resin The mechanism of HBP tougheningepoxy resin is to assemble functional groups in the outer layer of HBP molecules, which reduces the degree of molecular chain entanglement in the system and reduces the crystallinity, thereby regulating the phase structure of EP and improving the toughness of the resin system. Some scholars have synthesized hyperbranched polyurethane (HBPu) using a quasi-one-step method, and then used it to toughen acid anhydride-cured bisphenol A-type glycidyl ether (DGEBA). Research shows that after the introduction of HBPu, the resin viscosity of the uncured EP system is significantly reduced; the impact properties of cured EP are significantly improved. 7. Nanoparticle toughened epoxy resin Nanoparticles have become one of the hot topics in recent materials research due to their synergistic effect on both strengthening and toughening of polymers, which is attributed to properties such as nanoparticle surface effects and quantum size effects. Among them, inorganic fillers are widely used because of their low cost, low thermal expansion and shrinkage, and high elastic modulus and impact toughness of the composite materials produced. For example: Nano-zirconia (ZrO2), etc. Carbon nanomaterials, including CNT and graphene (GE), have a higher surface area to volume ratio due to their unique one- and two-dimensional structures, making them more conducive to improving the mechanics, electricity, thermal and barrier properties of the polymer matrix. Properties are currently a hot research topic in material modification. Due to the low surface activation energy of carbon nanomaterials, their compatibility with EP is not ideal, so researchers modified the carbon nanomaterials for use. Organic nanoelastomers, such as carboxyl nitrile elastomers, butylbutylene elastomers, etc., in addition to the characteristics of nanomaterials, also have the toughness of elastomers, and have good compatibility with EP. They are a type of elastomer with broad development prospects material. 8. Ionic liquid toughened epoxy resin Ionic liquids are molten salts composed of inorganic anions and organic cations. They are liquid at or near room temperature. They are recognized as "green materials" because of their non-volatility. Ionic liquids have "designability" and are used as plasticizers, lubricants, nucleating agents and antistatic agents for polymers. Some scholars have used butane ionic liquids to dope GE-modified EP composites, and their tensile properties and bending properties have also been significantly improved.  9. Composite toughened epoxy resin With the development of technology, researchers have realized that using two toughening agents in combination has better application effects than a single toughening agent. EP/(GE/KH–GE)/MWCNTs-OH composites were prepared by adding GE and hydroxylated multi-walled CNTs (MWCNTs-OH) to EP. The results show that GE/KH–GE and MWCNTs-OH have a synergistic toughening effect on EP without affecting the mechanical properties of EP. 10. Flexible segment curing agent toughens epoxy resin Methods for modifying EP based on physical or chemical principles have shortcomings such as complex and lengthy process routes. By using macromolecular curing agents containing flexible segments, after the EP is cured, the flexible segments are naturally bonded to the resin system. In the three-dimensional cross-linked network, on the one hand, it improves the flexibility of the molecules and promotes plastic deformation of the resin structure. On the other hand, the flexible segments also produce microscopic phase separation structures in the resin system, which can alleviate stress concentration. Therefore, flexible segment curing agents can greatly improve the toughness of EP without increasing process complexity. Compared with traditional rigid aromatic amine curing agents, after curing EP with aromatic amine curing agents (RAn) containing flexible groups such as ether bonds (—O—) and saturated alkane chains [—(CH2)n—], the resin system has a better The tensile properties and impact properties have been improved to a certain extent.   Outlook With an in-depth understanding of the toughening mechanism and based on the continuously improved material genome technology, on the basis of traditional toughening and reinforcement, new toughening methods/processes and the development of new multi-functional toughening agents can be further improved. Thermal properties and endowed with properties such as thermal conductivity, electrical conductivity, wave absorption, electromagnetic shielding, damping and shock absorption.  

  Background Currently, almost all commercialized epoxy resins are petroleum-based, and bisphenol A epoxy resin (DGEBA) accounts for about 90% of production. Bisphenol A is one of the most widely used industrial compounds in the world. However, in recent years, with the deepening of people's understanding of the biological toxicity of bisphenol A, many countries have banned the use of bisphenol A in plastic packaging and containers for food. In addition, DGEBA is easy to burn and cannot extinguish automatically after leaving the fire, which also limits its application scope. Therefore, the use of bio-based raw materials to prepare epoxy resin has gradually become a research hotspot in recent years.   Application Bio-based epoxy resin has wide application prospects in the fields of automobiles, transportation, culture and sports, woodware, home furnishing, and construction. In particular, the demand for electronic appliances and coatings industries is growing. Composite materials and adhesives are increasingly used in various fields. As well as the advancement of the global green and sustainable development strategy, bio-based epoxy resin will usher in excellent development opportunities and market space.   Challange In recent years, researchers have designed and synthesized a variety of bio-based compounds with heterocyclic, aliphatic and aromatic rings to replace petroleum-based bisphenol A for the preparation of epoxy resins. However, the thermal stability and mechanical properties of current bio-based epoxy resins are still difficult to match those of bisphenol A-type epoxy resins. Therefore, it is still a big challenge to design and synthesize bio-based monomers that can meet the high performance and functional requirements of bio-based epoxy resins.It is also an important step to broaden the application scope of bio-based polymer materials and enhance their competitive advantages over petroleum-based polymer materials. At present, bio-based epoxy resins mainly include high-temperature resistant bio-based epoxy resins, intrinsic flame-retardant bio-based epoxy resins, toughening of bio-based epoxy resins, degradable and recycled bio-based epoxy resins, etc.   Development trend With the diversification of molecular structure designs of bio-based compounds, the high-performance and functional advantages of bio-based epoxy resins have gradually become more prominent, and the composite materials constructed from them have shown excellent comprehensive properties. After analysis and data review, the future development trends of bio-based epoxy resins mainly include the following directions: Build a stable bio-based raw material supply system. Synthesize new bio-based epoxy resins from non-food sources. Construct a structure-function integrated bio-based epoxy resin polymer material system. Design degradable, self-healing and recyclable bio-based thermoset polymer materials. Nanjing Yolatech provides all kinds of high purity and low chlorine epoxy resins and specialty 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.  

I. Introduction One of the most important parameters and starting points for the development of epoxy resin formulations is the epoxy resin curing mechanism and the selection of the specific curing agent to be used. Dicyandiamide is one of the most widely used catalysts for curing one-component epoxy adhesives. This type of adhesive has a long shelf life at room temperature, but offers relatively fast curing at temperatures above 150°C. Dicyandiamide cured epoxy adhesives have a wide range of uses, especially in the transportation, general assembly and electrical/electronic markets.   II. Dicyandiamide Dicyandiamide (also known as “dicy”) is a solid latent curing agent that reacts with both the epoxy group and the secondary hydroxyl group. This curing agent is a white crystalline powder that is easily incorporated into epoxy formulations. Figure 1 is a graphical representation of the dicyandiamide molecule.     This curing agent cures through nitrogen-containing functional groups and consumes the epoxy and hydroxyl groups in the resin. The advantage of dicyandiamide is that it reacts with the epoxy resin only when heated to the activation temperature, and the reaction stops once the heat is removed. It is widely used in epoxy resins and has a long shelf life (up to 12 months). Longer shelf life can be obtained by refrigerated storage. Due to its delayed cure (long shelf life) and excellent properties, dicyandiamide is used in many “Class B” film adhesives. Dicyandiamide is also one of the main catalysts for one-component, high-temperature curing epoxy adhesives. In adhesive formulations, dicyandiamide is used in quantities of 5-7 pph for liquid epoxy resins and 3-4 pph for solid epoxy resins. it is generally dispersed with epoxy resins by ball milling. Dicyandiamide forms very stable mixtures with epoxy resins at room temperature because it is insoluble at low temperatures. The particle size and distribution of the epoxy-dicyandiamide system is critical for extending its shelf life. In general, the best performance is produced when the particle size of the dicyandiamide is less than 10 microns. Fumed silica is commonly used to keep the dicyandiamide particles suspended and evenly distributed in the epoxy resin. When formulated as a one-component adhesive system, epoxy dicyandiamide is stable when stored at room temperature for six months to one year. It is then cured by exposure to 145-160°C for approximately 30-60 minutes. Because of the relatively slow reaction rate at lower temperatures, the addition of 0.2% ~ 1.0% phenyl dimethylamine (BDMA) or other tertiary amine accelerators is sometimes used to reduce the cure time or lower the cure temperature. Other common accelerators are imidazole, substituted urea and modified aromatic amines. Substituted dicyandiamide derivatives can also be used as epoxy curing agents with higher solubility and lower activation temperatures. These techniques can reduce the activation temperature of epoxy-dicyandiamide mixtures to 125°C. Dicyandiamide-cured epoxy resins have good physical properties, heat and chemical resistance. Liquid epoxy cured with 6 pph dicyandiamide has a glass transition temperature of about 120°C, while high temperature curing with aliphatic amines will provide a glass transition temperature of no greater than 85°C.   III. One-component adhesive formulations In one-component epoxy adhesives, the curing agent and resin are compounded together as a single material through an adhesive formulation. The curing agent system is selected so that it reacts with the resin only under appropriate processing conditions. Dicyandiamide-cured epoxy resins are very brittle. Through the use of toughening agents, such as terminated carboxybutyronitrile (CTBN), it is possible to formulate very elastic and tough adhesives without sacrificing the good properties inherent in unmodified systems. With toughened dicyandiamide-cured epoxies, peel strengths are approximately 30 lb/in and tensile shear strengths are in the range of 3000-4500 psi. Toughened dicyandiamide-cured epoxy adhesives also exhibit good resistance to heat cycling. The most effective accelerators for dicyandiamide systems are probably substituted ureas because of their synergistic effect on the performance of the adhesive and their exceptionally good latent delay. It has been shown that the addition of 10 pph of substituted urea to 10 pph of dicyandiamide will produce a bisphenol- a (DGEBA) epoxy liquid diglycidyl ester binder system that cures in only 90 min at 110 °C. However, this adhesive has a shelf life of three to six weeks at room temperature. If longer curing times are acceptable, curing can even be achieved at temperatures as low as 85°C.  

A dielectric is any insulating medium between two conductors. Simply put, it is non-conductive material. Dielectric materials are used to make capacitors, to provide an insulating barrier between two conductors (e.g., in crossover and multilayer circuits), and to encapsulate circuits.   Dielectric Properties Epoxy resin usually has the following four dielectric properties:VR, Dk, Df and dielectric strength. Volume resistivity (VR): It is defined as the resistance measured through the material when a voltage is applied for a specific period of time. According to ASTM D257, for insulation products, it is usually greater than or equal to 0.1 tera ohm-meter at 25°C and greater than or equal to 1.0 mega ohm-meter at 125°C. Dielectric constant (Dk): it is defined as the ability of the material to store charge when used as a capacitor dielectric. According to ASTM D150, it is usually less than or equal to 6.0 at 1KHz and 1MHz, and is a dimensionless value because it is measured as a ratio. The dissipation factor (Df) (also known as the loss factor or dielectric loss): defined as the power dissipated by the medium, usually less than or equal to 0.03 at 1KHz, less than or equal to 0.05 at 1MHz. Dielectric strength (sometimes called breakdown voltage): is the maximum electric field that the material can withstand before breakdown. This is an important characteristic for many applications that require running high currents or amperages. As a general rule of thumb, the dielectric strength of epoxy resins is about 500 volts per mil at 23°C for insulating products. As a practical example, if an electronic circuit needs to resist 1000 volts, a minimum of 2 mils of dielectric epoxy is required. Volume resistivity, dielectric constant, and dissipation factor can be determined experimentally by the adhesive manufacturer; however, dielectric strength depends on the application. Users of epoxy resins should always verify the dielectric strength of the adhesive for their particular application.   Variability of dielectric properties Many dielectric properties will vary with factors unrelated to the properties of the host material, such as: temperature, frequency, sample size, sample thickness and time. Some external factors and how they affect the final results. VR and Temperature As the temperature of the material increases, the VR decreases. In other words, it is no longer an insulator. The main reason for this is that the material is above its glass transition temperature (Tg) and the molecular motion of the monomers entangled in the polymer network is at its highest level. This not only means lower insulation compared to room temperature, but also leads to lower strength and sealing.  Dk and temperature The dielectric constant of room temperature cured epoxy resins increases with temperature. For example, the value is 3.49 at 25°C, becomes 4.55 at 100°C, and 5.8 at 150°C. In general, the higher the value of Dk, the less electrically insulating the material is. Dk and frequency (Rf)  In general, Dk decreases with increasing frequency. As described in the effect of temperature on Dk, room temperature cured epoxy resin has a Dk value of 3.49 at 60Hz, a Dk value of 3.25 at 1KHz and a Dk value of 3.33 at 1MHz. In other words, as Rf increases, the insulating properties of the adhesive increase. Therefore, the lower the Dk value, the more the material acts like an insulator.    Common Applications Dielectric adhesives are used in most semiconductor and electronic packaging applications. Some examples include: semiconductor flip chip underfill, SMD placement on PCBs and substrates, wafer passivation, spherical tops for ICs, copper ring dipping and general PCB potting and encapsulation. All of these areas require maximum insulation to eliminate and prevent any electrical shorts.    Insulation Products Epoxy Technologies offers a wide range of products for dielectric applications that have structural, optical and thermal properties as well as good dielectric properties. All dielectric products are electrical insulators, but many are also heat conductors.

Benzoxazine compounds can be synthesized from phenols, formaldehydes and amines with oxygen nitrogen heterocyclic structure with halogen free, which can be homopolymerized to form a polybenzoxazine thermoset networks by heating, also can be co-cured with traditional thermosetting resins like epoxy resin, phenolic resin.   Benzoxazine resins, when heated without curing agent, homopolymerize to form a rigid, nitrogen contained and strong cross-linking network structure that can be used for manufacturing products with excellent mechanical property, high temperature resistance and flame retardancy(UL94-V0). Furthermore, benzoxazine, as a curing agent, can be used in conjunction with all the epoxy resins, phenolic resins etc. to achieve high thermal resistance, strong, low CTE, flame retardancy with halogen free. With these qualities, benzoxazines offer many advantages for formulating halogen-free systems to be used in stringent requirement of CCLs, high speed PCBs, flame retardancy electrical materials and others.   Benzoxazine Key Properties The flame retardancy of benzoxazine series can reach UL-94 V0 level with halogen free, which can be used to improve flammability resistance of products. No byproduct releasing during the curing process, and the dimensional shrinkage rate almost 0. The whole series of products have low water absorption, which can greatly improve the rate of good products. The excellent dielectric property of low dielectric series products shows less effect in frequency fluctuation, witch is intended for use in M2/M4 class PCBs. Benzoxazine products with a wide coverage of Tg and selectivity(150~450℃), and with char yield 78% at 800℃. Benzoxazine resins can be toughened by using unique patented technology, which can significantly improve the machinability of plate products.

The viscosity of water-based resins is a crucial parameter in various industrial applications, influencing the ease of application, flow characteristics, and overall performance of the end product. Several key factors determine the viscosity of these resins, including molecular weight, solubility, and the presence of solid particles. Understanding these factors is essential for optimizing resin formulations and achieving the desired properties.   Molecular Weight One of the primary factors affecting the viscosity of water-based resins is their molecular weight. Higher molecular weight resins exhibit higher viscosity. This phenomenon occurs because longer polymer chains in high molecular weight resins lead to greater intermolecular interactions. These interactions create more resistance to flow, thus increasing the viscosity. In essence, as the molecular weight increases, the mobility of the resin molecules in water decreases, resulting in a thicker, more viscous solution. 1. Polymer Chain Length and Interactions Longer polymer chains in high molecular weight resins have more extensive entanglements and interactions between chains. These interactions can include van der Waals forces, hydrogen bonding, and even ionic interactions, depending on the resin's chemical structure. These forces collectively hinder the movement of resin molecules, increasing the energy required for flow and thereby raising the viscosity. 2. Practical Applications In practical applications, resins with higher molecular weights are often used when a thicker consistency is desired. For example, in coatings that require a high-build film or adhesives that need strong bonding capabilities, higher molecular weight resins provide the necessary viscosity and performance characteristics.   Solubility The solubility of the resin in water also significantly impacts its viscosity. Resins with lower solubility tend to have higher viscosity. This is because poorly soluble resin molecules do not disperse well in water, leading to aggregation or clustering of the resin molecules. These aggregates create a higher resistance to flow, thereby increasing the viscosity. Essentially, when the solubility of the resin decreases, the uniform distribution of resin molecules in the water is compromised, leading to a more viscous mixture. 1. Aggregation and Clustering Low-solubility resins tend to form aggregates or clusters in water. These clusters increase the effective particle size within the solution, which in turn increases the resistance to flow. The presence of these larger, less dispersed particles means that more energy is required to move the solution, resulting in higher viscosity. 2. Applications Requiring Specific Solubility In applications where specific solubility properties are needed, the choice of resin solubility is critical. For instance, in waterborne paints and coatings, a balance between solubility and viscosity must be achieved to ensure easy application while maintaining good film-forming properties.   Solid Particles The shape and size of solid particles within the resin also play a vital role in determining viscosity. Irregularly shaped particles and larger particles contribute to higher viscosity. Irregular shapes and larger sizes increase the friction and interaction between particles and the surrounding medium, thereby increasing resistance to flow. As a result, resins containing such particles exhibit higher viscosity compared to those with smaller, more regularly shaped particles. 1. Particle Shape and Surface Area Irregularly shaped particles have larger surface areas and more points of contact with other particles and the surrounding fluid. This increased surface area leads to higher friction and interaction forces, making it more difficult for the particles to move past each other, thus increasing viscosity. 2. Size Distribution The size distribution of solid particles also affects viscosity. A wide size distribution can lead to a more compact packing of particles, increasing the density and interaction within the resin, thereby increasing viscosity. Conversely, a narrow size distribution can result in a more uniform and potentially lower viscosity.   Practical Implications Understanding these factors is crucial for formulating water-based resins with the desired viscosity. For instance, in applications requiring easy application and smooth flow, resins with lower molecular weight and higher solubility might be preferred. Conversely, for applications needing thicker consistency and higher viscosity, such as in certain coatings or adhesives, higher molecular weight resins or those with lower solubility might be more suitable.   Tailoring Resin Properties Manufacturers can tailor resin properties by adjusting molecular weight, solubility, and particle characteristics to meet specific application requirements. By optimizing these factors, it is possible to achieve the desired balance between viscosity, performance, and application ease.   Conclusion In summary, the viscosity of water-based resins is influenced by molecular weight, solubility, and the characteristics of solid particles within the resin. By carefully considering and adjusting these factors, manufacturers can tailor the properties of water-based resins to meet specific application requirements, ensuring optimal performance and functionality. This nuanced understanding allows for the development of high-quality resins that perform effectively in a variety of industrial applications.  

  n-Heptanol (1-Heptanol) and n-Hexanol (1-Hexanol) are both primary alcohols, which means they each have a hydroxyl group (-OH) attached to a primary carbon atom. These alcohols are important in various industrial applications due to their unique properties.   n-Heptanol (1-Heptanol) Chemical Structure and Properties Chemical Formula: C7H16O Molecular Weight: 116.2 g/mol Boiling Point: 175.8 °C (348.4 °F) Density: 0.818 g/cm³ 1-Heptanol, also known as heptan-1-ol or heptyl alcohol, is a clear, colorless liquid with a mild, characteristic odor. It is slightly soluble in water but more soluble in organic solvents such as ethanol and ether.   Uses and Applications Flavoring Agent: Due to its pleasant odor, 1-Heptanol is used in the flavor and fragrance industry to impart fruity and floral notes. Chemical Intermediate: It serves as a precursor in the synthesis of various esters, which are used in perfumes and flavorings. Solvent: 1-Heptanol can be used as a solvent in the formulation of resins, coatings, and pharmaceuticals. Lubricant Additive: It is sometimes used as an additive in lubricants to enhance performance and stability.   Production 1-Heptanol is produced through the catalytic hydrogenation of heptanal or by the hydroformylation of hexene followed by hydrogenation.   n-Hexanol (1-Hexanol) Chemical Structure and Properties Chemical Formula: C6H14O Molecular Weight: 102.2 g/mol Boiling Point: 157 °C (315 °F) Density: 0.814 g/cm³ 1-Hexanol, also known as hexan-1-ol or hexyl alcohol, is a colorless liquid with a slightly floral odor. It is moderately soluble in water and highly soluble in most organic solvents.   Uses and Applications Fragrance and Flavor: Similar to 1-Heptanol, 1-Hexanol is used in the fragrance industry to produce floral and green odors. Solvent: It acts as a solvent for lacquers, resins, and oils. Plasticizer: 1-Hexanol is used in the production of plasticizers, which are added to plastics to increase their flexibility. Intermediate in Chemical Synthesis: It is a building block in the synthesis of various chemicals, including plasticizers, pharmaceuticals, and surfactants.   Production 1-Hexanol is typically produced by the hydroformylation of pentene, followed by hydrogenation of the resulting aldehyde. Alternatively, it can be obtained from the reduction of hexanoic acid.   Conclusion n-Heptanol and n-Hexanol are versatile chemicals with a wide range of applications in various industries. Their roles as solvents, intermediates in chemical synthesis, and components in fragrances and flavors highlight their importance. Understanding their properties and production methods can help optimize their use in industrial processes and product formulations.  

With the rapid development of marine ports, terminals, offshore wind power and shipbuilding industry, the demand for concrete and steel structures in marine engineering is getting bigger and bigger. The durability and reliability of reinforced concrete structure is an important quality indicator for construction projects, and corrosion is an important factor affecting it, in the actual project, the various effects brought about by corrosion is one of the most important concerns of construction engineers. Long-term immersion in seawater or in humid corrosive environments can be damaged by environmental agents such as chloride ions, sulphate ions and CO2, so practical anti-corrosion measures can be used to ensure and extend the service life of these infrastructures.   We take advantage of the permeability of concrete and use epoxy resin protective coatings to penetrate into the concrete surface to a certain depth to block the pores completely or form a continuous film on the surface to close the pores, so that the concrete surface can be effectively protected.   Epoxy resin coating can be cured at room temperature, the cured coating film has good adhesion, bonding, while having good mechanical properties and corrosion resistance. As an excellent reinforcing and protective coating, epoxy resin coating has been widely used in the protection of reinforced concrete structures at home and abroad.   Epoxy resin protective coating performance characteristics Good adhesion with concrete Good resistance to acid and alkali corrosion Resistance to salt water immersion Good abrasion resistance Curing at room temperature, good constructability Good sealing and impermeability to concrete.

Amino resin can enhance the flexibility of the paint film, make it more wear-resistant, impact resistance, and improve the weather resistance of the paint film.   The role of amino resin mechanism Amino resin is a multifunctional polymer, with stable properties, high transparency, good hardness, water resistance and other advantages, it plays the role of crosslinking agent in the paint curing process. Amino resin and the base resin co-condensation at the same time, will also occur self-condensation reaction, so as to form a three-dimensional network structure, to enhance the mechanical strength of the paint film and chemical resistance.   Amino resin as a cross-linking agent Amino resin as a crosslinking agent, in 100 ℃ below the degree of reaction is low, but when the temperature rises to 150 ℃ or more, the degree of crosslinking reaction is significantly increased. It is noteworthy that even at 200°C, the degree of reaction is only close to 90%, indicating that the amino resin still has good reactivity at high temperatures. Amino resin as a crosslinking agent added to the paint, can effectively enhance the flexibility of the paint film. Its enhancement mechanism mainly has the following three aspects: 1. increase the elasticity of the paint film 2. reduce the surface tension of the film 3. enhance the adhesion of the coating   The type and characteristics of amino resin Amino resin types are diverse, according to its structure in the different functional groups, can be divided into polymerisation type part of alkylation, polymerisation type high subamino and monomer type high alkylation, etc., can also be divided into urea formaldehyde amino, isobutylation, n-butylation, benzene substitution of amino, part of the methyl etherification and complete methyl etherification and so on. These different types of amino resins in the reactivity, crosslinking temperature and the final film properties have their own characteristics.   Ratio of amino resin to acrylic resin Because the molecular weight of acrylic resin is large, and the molecular weight of monomer type HMMM is small, so in order to fully react, the amount of HMMM, it should be a lot of excess; Generally is controlled in the main body resin: amino resin = (1.7: 1 ~ 4: 1), based on the higher temperature, more likely to tend to self-crosslinking, so when the temperature is higher, the amount of amino resin should be increased, generally keep in the upper limit of the ratio, so as to ensure the effectiveness of the crosslinking reaction. In addition, if the amount of hydroxyl group contained in the main resin is high, the proportion of amino resin should be increased accordingly.   Nanjing Yolatech provides all kinds of high purity and low chlorine epoxy resins, 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.     We will be at your service 24 hours a day. Pls contact us freely.  

Product information 1.3-BAC is a diamine substance, it is colourless transparent and low viscosity liquid at room temperature, it has obvious ammonia smell, corrosive and combustible when it meets open fire. It belongs to cyclic aliphatic amine, when used as epoxy curing agent, it has both the high activity of aliphatic amine and the excellent mechanical properties, temperature resistance and yellowing resistance of alicyclic amine, it is often used in the preparation of high-quality epoxy adhesive products.   Application Mainly used as epoxy curing agent or preparation of modified epoxy curing agent, not only low viscosity, good operability, and excellent room temperature curing performance, its products in the mechanical properties, temperature resistance, water resistance, chemical resistance and other aspects of the excellent preparation of high-quality epoxy adhesives, flooring paints, etc., are widely used in high-end flooring, jewelry adhesive, crystal adhesive, stone adhesive industry; at the same time, due to its excellent mechanical properties, good operability, also used in composite materials. At the same time, due to its excellent mechanical properties and good operability, it is also used in composite material industry (automobile, wind blade, etc.).   Ratio Epoxy resin 128 (epoxy equivalent 190):100 Amount of curing agent: 17~20   Nanjing Yolatech provides all kinds of high purity and low chlorine epoxy resins, 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.   We will be at your service 24 hours a day. Pls contact us freely.