What Is Flexible Epoxy?

Epoxy resin adhesive is a kind of engineering adhesive formulated from epoxy resin base material, curing agent, diluent, accelerator and filler. Because of its good bonding performance, good functionality, low price, and simple bonding process, it has been widely used in the fields of home appliances, automobiles, water conservancy and transportation, electronics and aerospace industry in recent decades. With the continuous development of high and new technology and nanotechnology, in recent years, the modification of epoxy resin has been deepened, interpenetrating networks, chemical copolymerization and nanoparticles

Epoxy resin adhesive is a kind of engineering adhesive formulated from epoxy resin base material, curing agent, diluent, accelerator and filler. Because of its good bonding performance, good functionality, low price, and simple bonding process, it has been widely used in the fields of home appliances, automobiles, water conservancy and transportation, electronics and aerospace industry in recent decades. With the continuous development of high and new technology and nanotechnology, in recent years, the modification of epoxy resin has been deepened, interpenetrating networks, chemical copolymerization and nanoparticles
Toughening and other methods are widely used, and there are more and more varieties of various high-performance adhesives formulated from epoxy resins. [1]
Epoxy adhesives (referred to as epoxy adhesives or epoxy adhesives) have been around since 1950 and have only been around for more than 50 years. However, with the successive advancement of various adhesive theories in the middle of the 20th century, and the in-depth development of basic research work such as adhesive chemistry, adhesive rheology, and adhesive failure mechanism, the adhesive properties, varieties, and applications have made rapid development. Epoxy resin and its curing system have also emerged with its unique and excellent performance and the continuous emergence of new epoxy resins, new curing agents and additives, which have become an important type of adhesive with excellent performance, many varieties and wide adaptability.
Chinese name
Epoxy adhesive
Foreign name
epoxy resin adhesive
Overview
Epoxy adhesive
Classification
Classification by adhesive form
Definition
Epoxy adhesive is mainly made of epoxy resin

Definition of epoxy adhesive

Epoxy adhesives are mainly composed of epoxy resin and curing agent. In order to improve certain properties, to meet different purposes, tougheners, diluents, accelerators, coupling agents and other auxiliary materials can be added. Due to the high bonding strength and general versatility of epoxy adhesives, they have been called "universal adhesives" and "strong adhesives". They are used in aviation, aerospace, automotive, machinery, construction, chemical, light industry, electronics, electrical appliances, and daily life And other fields have been widely used.

Classification of epoxy adhesive

There are many types of epoxy resin adhesives, and their classification methods and classification indicators have not been unified.
Classified by adhesive form
Solvent-free adhesives, (organic) solvent-based adhesives, water-based adhesives (also divided into water-emulsion type and water-soluble type), paste adhesives, film adhesives (epoxy film), etc.
Classified by curing conditions
1) Cold curing glue (without heating curing glue). Divided into:
Low temperature curing glue, curing temperature <15 ;
Room temperature curing glue, curing temperature 15-40 .
2) Thermal curing glue. It can be divided into:
Medium temperature curing glue, curing temperature is about 80-120 ;
High temperature curing glue, curing temperature> 150 .
3) Other methods of curing glue, such as light curing glue, wet surface and water curing glue, latent curing glue, etc.
(3) Classification by bonding strength
1) Structural adhesives have high shear and tensile strength, and should also have high uneven tearing strength, so that the glued joint can withstand vibration, fatigue and impact loads for a long time. It should also have high heat resistance and weather resistance. Usually the steel-steel room temperature shear strength is> 25MPa and tensile strength is 33MPa. Uneven tearing strength> 40kN / m.
2) Structural adhesive with secondary force, can withstand medium load. Usually the shear strength is 17-25MPa, and the uneven tearing strength is 20-50kN / m.
3) Non-structural adhesive, that is, universal adhesive. Its room temperature strength is still relatively high, but as the temperature increases, the bonding strength decreases rapidly. It can only be used in areas with little stress.
By use
1) General purpose adhesive.
2) Special adhesives. Such as high temperature resistant glue (use temperature 150 ), low temperature resistant glue (can withstand -50 or lower temperature), strain glue (for pasting strain gauge), conductive glue (volume resistivity 10-3 10-4 · Cm), sealant (vacuum seal, mechanical seal), optical glue (colorless and transparent, light aging resistance, refractive index matching optical components), corrosion-resistant glue, structural glue, etc.
Other classifications
It can also be classified according to the type of curing agent, such as amine-cured epoxy adhesive, acid anhydride cured adhesive, and the like. It can also be divided into two-component glue and single-component glue, pure epoxy glue and modified epoxy glue (such as epoxy-nylon glue, epoxy-polysulfide rubber glue, epoxy-butyronitrile glue, epoxy- Polyurethane glue, epoxy-phenolic glue, silicone epoxy glue, acrylic epoxy glue, etc.).

Introduction of epoxy resin adhesive composition

Epoxy resin adhesive is composed of epoxy resin, curing agent, plasticizer, accelerator, diluent, filler, coupling agent, flame retardant, stabilizer and so on. Among them, epoxy resin, curing agent and toughening agent are indispensable components, and others are determined as needed.
1. Epoxy resin Epoxy resin is a high molecular compound with two or more epoxy groups in the molecule and relatively low molecular weight. 1. There are many types and types of epoxy resins, but bisphenol A glycidol. Ether epoxy resins are often called bisphenol A epoxy resins and are the most important type. It accounts for 90% of total epoxy resin production. The molecular structure is very long and I won't say it here! If you want to know, you can click on the epoxy resin. There will be detailed instructions! Here are just a brief description: 1. Bisphenol A epoxy resin is also called general epoxy resin and standard epoxy resin. It is named as E epoxy resin in China. It is composed of bisphenol (BPA or DPP) and epoxy resin. Chloropropane (ECH) is obtained by polycondensation under sodium hydroxide.
According to different raw material ratios, reaction conditions and different methods, viscous liquids with low relative molecular mass and solids with high relative molecular mass and high softening point can be prepared with different degrees of polymerization. The average relative molecular mass is 300 ~ 7000. Appearance is almost colorless or light yellow transparent viscous liquid or flake-like brittle solid. The epoxy resin itself is a thermoplastic linear polymer. When heated, the viscosity of the liquid resin becomes low, and the solid resin softens or melts. Soluble in acetone, methyl ethyl ketone, cyclohexanone, ethyl acetate, benzene, toluene, xylene, absolute ethanol, ethylene glycol and other organic solvents.
2. Hydrogenated bisphenol A epoxy resin The chemical name of hydrogenated bisphenol A epoxy resin is hydrogenated bisphenol A diglycidyl ether, which is a hexahydrobisphenol A and epichlorohydrin obtained by hydrogenation of bisphenol A. It is obtained by polycondensation under the catalysis of sodium hydroxide. It is an epoxy resin with very low viscosity, long gel time, and excellent weather resistance.
3. Bisphenol F epoxy resin The chemical name of bisphenol F epoxy resin is bisphenol F diglycidyl ether, abbreviated as DGEBF or BPF. It is formed by the reaction of phenol and formaldehyde under an acid catalyst to form bisphenol F. Colorless or light yellow transparent viscous liquid prepared by polycondensation of oxychloropropane under sodium hydroxide catalyst
4. Bisphenol S epoxy resin The chemical name of bisphenol S epoxy resin is bisphenol S diglycidyl ether, which is referred to as BPS or KGEBS for short. It is prepared from bisphenol S and epoxy propane under sodium hydroxide catalyst. The obtained bisphenol S epoxy resin has high heat resistance, a heat distortion temperature 60-700C higher than that of bisphenol A epoxy resin, and the cured product is stable and has good solvent resistance.
5. Bisphenol P-type epoxy resin Bisphenol P-type epoxy resin is made by synthesizing bisphenol P with 3-chloropropene and phenol as main raw materials, and then polycondensing with epichlorohydrin in sodium hydroxide under the catalyst. The epoxy value of bisphenol P-type epoxy resin is 0.45eq / 100g, the content of organic chlorine is 1.38 * 10-3eq / 100g, and the content of inorganic chlorine is 1.84 * 10-4eq / 100g. The molecular chain of bisphenol P-type epoxy resin has great flexibility and low temperature. Good flowability, lower viscosity than bisphenol A epoxy resin, higher compression strength and impact strength than bisphenol A epoxy resin.
6, methylol bisphenol A epoxy resin
7, brominated bisphenol A epoxy resin
8. Phenolic epoxy resins Phenolic epoxy resins mainly include phenol novolac epoxy resin and o-cresol novolac epoxy resin, and resorcinol novolac epoxy resin. In addition, tetraphenol-based ethane epoxy resins also belong to phenolic epoxy resins.
1. Phenol novolac epoxy resin (EPN) ----- It is a novolac resin obtained by polycondensation reaction between phenol and formaldehyde in an acidic medium, and then with an excess of epichlorohydrin in the presence of sodium hydroxide Linear brownish-yellow viscous liquid or semi-solid obtained by polycondensation.
2. O-cresol novolac epoxy resin (ECN) ------ is a linear o-cresol novolac resin obtained by the condensation of o-cresol and formaldehyde, and then reacts with epichlorohydrin in the presence of sodium hydroxide, A yellow to amber solid obtained after multiple steps of treatment.
3. Epoxy resorcinol formaldehyde resin ----- The chemical name is resorcinol formaldehyde tetraglycidyl ether, which is a tetrafunctional phenolic resin prepared by the reaction of resorcinol and formaldehyde with oxalic acid as a catalyst. An orange-yellow viscous liquid obtained by polycondensation with epichlorohydrin in the presence of sodium hydroxide.
4. Tetraphenol-based ethane epoxy resin ------ Chemical name is tetraphenol-based ethane glycidyl ether (PGEE), which is obtained by reacting phenol with glyoxal in the presence of an acid catalyst Prepared by reaction with epichlorohydrin under sodium hydroxide catalysis
5. Naphthol novolac epoxy resin (EEPN) ----- It is prepared by polycondensation of a-naphthol and formaldehyde solution to synthesize novolac resin, and then react with epichlorohydrin under the catalysis of sodium hydroxide.
9. Glycidyl ester epoxy resin 1. Tetrahydrophthalic acid diglycidyl ester Tetrahydrophthalic acid diglycidyl ester is formed by the reaction of tetrahydrophthalic acid and cyclohexylchloropropane 2. Diglycidyl phthalate (yellow viscous liquid), also known as propylene phthalate, is the corresponding salt formed by the reaction of phthalic acid and potassium carbonate. It is then made with epichlorohydrin under the action of tertiary amines. 3, Diglycidyl isophthalate (white solid powder) Diglycidyl isophthalate is also known as glycidyl isophthalate. Prepared by the reaction of phthalic acid with epichlorohydrin. 4. Glycidyl terephthalate (white solid powder) Glycidyl terephthalate, also known as propylene terephthalate, is produced by the reaction of terephthalic acid and epichlorohydrin.
10. Glycidylamine type epoxy resin 11. The chemical name of alicyclic epoxy resin is alicyclic diepoxide, which is usually a kind of ring obtained by oxidizing the corresponding unsaturated aliphatic and family compounds with a peroxide organic acid. Oxygen compound. The water content in the structure has an alicyclic ring, and the epoxy group is connected to the alicyclic ring. Since epichlorohydrin is not used as a raw material in the synthesis, the organic chlorine content of the product is 0, which has excellent electrical properties, high volume resistivity and surface resistivity. , Good resistance to arc and leakage. The cured product has a large crosslinking density, high heat resistance, good weather resistance, resistance to ultraviolet light and resistance to electron radiation.
12. TDE-85 epoxy resin (chemical name is 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester)
13. Polybutadiene epoxy resin Polybutadiene epoxy resin, also known as epoxidized polybutadiene resin, uses 1,3-butadiene as the raw material and sodium metal as the catalyst in the solvent.
14. Due to the introduction of fluorine atoms, the fluorinated epoxy resin makes the molecular structure compact, and the carbon and fluorine atoms are closely arranged around the resin main chain. Therefore, the surface tension, friction coefficient, and refractive index are very low, which has excellent corrosion resistance, wear resistance, heat resistance, pollution resistance, and durability. But the price is too high for general use.
15. Polyether epoxy resin is prepared by the polycondensation reaction of polypropylene glycol and epichlorohydrin in the presence of sodium hydroxide.
16. Polyurethane epoxy resin, also known as epoxy urethane resin, is made of polyester (or ether) polyol and epichlorohydrin under the action of BF3 and NaOH. Polyol glycidyl ether is then added to polycondensation with diisocyanate. be made of
17. Naphthalene-based epoxy resin is obtained by synthesizing linear naphthol novolac resin or dihydroxynaphthalene (NDOL) with epichlorohydrin under the catalysis of sodium hydroxide, which has high heat resistance and low water absorption. Low linear expansion coefficient;
18. Silicone epoxy resin is an epoxide containing silicon in its molecular structure. It is made by polycondensation of polymethylphenylsiloxane and epoxy resin. Toluene is a solution, a light yellow uniform liquid 19. The organic titanium epoxy resin is obtained by reacting a hydroxyl group in a bisphenol A epoxy resin with n-butyl titanate. The metal element titanium is introduced into the resin, which not only solves the problems of increased water absorption, moisture resistance, and reduced electrical properties caused by the presence of hydroxyl groups, but also because the resin has oxygen atoms with P electrons and titanium atoms with D electron absent. The direct connection leads to the PD conjugation effect existing in the macromolecular chain, and the heat aging performance is significantly improved, and the dielectric performance is better. Appearance is yellow to amber high viscosity transparent liquid.
20. The chemical name of organoboron epoxy resin is polybutylene oxide carborane. 21. Oxygen-containing epoxy resin refers to resins with phosphorus and non-oxygen groups in the same water content. The epichlorohydrin is reacted to prepare a phosphorus-containing epoxy resin.

Epoxy Adhesive Adhesive Principle

Epoxy adhesive is a liquid or solid adhesive composed of epoxy resin, curing agent, accelerator, modifier, diluent, filler, etc. The adhesive process of epoxy adhesive is a complex physical and chemical process, including the steps of wetting, adhesion, curing, etc., and finally produces a cured product with a three-dimensional crosslinked structure, which combines the adherends into a whole. Adhesive properties (strength, heat resistance, corrosion resistance, impermeability, etc.) not only depend on the structure and performance of the adhesive and the structure and adhesive properties of the surface of the adherend, but also the joint design, preparation process and storage of the adhesive As well as the bonding process, it is also restricted by the surrounding environment (stress, temperature, humidity, media, etc.). Therefore, the application of epoxy adhesive is a systems engineering. The performance of the epoxy adhesive must be compatible with the above factors that affect the bonding performance in order to obtain the best results. Using the same formulation of epoxy adhesive to glue objects of different properties, or using different bonding conditions, or in different environments, the performance will be greatly different.

Advantages of epoxy adhesive

Compared with other types of adhesives, epoxy adhesives have the following advantages:
(1) Epoxy resin contains a variety of polar groups and highly active epoxy groups, so it has strong resistance to many polar materials such as metal, glass, cement, wood, plastic, especially materials with high surface activity. At the same time, the cohesive strength of the epoxy cured product is also very large, so its adhesive strength is very high.
(2) When the epoxy resin is cured, basically no low molecular volatiles are generated. The volume shrinkage of the adhesive layer is small, about 1% to 2%, and it is one of the varieties with the smallest curing shrinkage among thermosetting resins. After adding filler, it can be reduced to below 0.2%. The linear expansion coefficient of the epoxy cured product is also small. Therefore, the internal stress is small, and the influence on the bonding strength is small. In addition, the creep of the epoxy cured product is small, so the dimensional stability of the adhesive layer is good.
(3) There are many types of epoxy resins, curing agents and modifiers. The formulation can be designed with reasonable and clever formula to make the adhesive have the required processability (such as rapid curing, room temperature curing, low temperature curing, water curing, low viscosity , High viscosity, etc.), and have the required performance (such as high temperature resistance, low temperature resistance, high strength, high flexibility, aging resistance, electrical conductivity, magnetic conductivity, thermal conductivity, etc.).
(4) It has good compatibility and reactivity with a variety of organic substances (monomers, resins, rubbers) and inorganic substances (such as fillers), and is easy to modify by copolymerization, crosslinking, blending, filling, etc. Improve the performance of the adhesive layer.
(5) Good corrosion resistance and dielectric properties. Resistant to acid, alkali, salt, solvent and other media. The volume resistivity is 1013-1016 · cm, and the dielectric strength is 16-35kV / mm.
(6) The general-purpose epoxy resin, curing agent and additives have many origins, large output, easy preparation, contact compression molding, and large-scale application.

Disadvantages of epoxy adhesive

The main disadvantages of epoxy adhesives-
(1) When it is not toughened, the cured product is generally brittle, with poor peel resistance, crack resistance, and poor impact resistance.
(2) Low adhesion to materials with low polarity (such as polyethylene, polypropylene, fluoroplastic, etc.). Surface activation must be performed first.
(3) Some raw materials such as reactive diluents and curing agents have different degrees of toxicity and irritation. It should be avoided when designing formulas, and ventilation and protection should be strengthened during construction operations.

Preparation of epoxy adhesive

The preparation methods of epoxy adhesives are roughly the following types:
(1) Reaction of active hydride with epichlorohydrin;
(2) liquid phase oxidation of the double bond with hydrogen peroxide or peracid (such as peracetic acid);
(3) air oxidation of a double bond compound;
(4) Other.

Application of epoxy adhesive

Modified epoxy resin adhesive and preparation method thereof overcome the shortcomings of brittleness and poor temperature resistance of general epoxy adhesives, and its main technical characteristics are polyurethane prepolymer modified epoxy resin (component A) and homemade curing agent. (Component B) is formulated into a curing system with high temperature resistance, good toughness, and high reactivity at a ratio of 10: 1 to 1: 1 (weight ratio). The polyurethane prepolymer is an isocyanate group-terminated polysiloxane polyurethane prepolymer that is reacted with hydroxyl-terminated polysiloxane and diisocyanate at a certain ratio and under certain conditions. Modified. The self-made curing agent is composed of a diamine, an imidazole compound, a silane coupling agent, an inorganic filler, and a catalyst. This modified epoxy resin adhesive can be cured at room temperature, can be used for a long time at 200 ° C, or can be cured at -5 ° C and resistant to 150 ° C; the adhesive strength is 15-30MPa; the T-peel strength is 35-65N / cm, which is excellent It is resistant to oil, water, acid, alkali, and organic solvents. It can bond wet surfaces, oil surfaces and metals, plastics, ceramics, hard rubber, wood, etc.
Painting field
Application in automobiles: chassis primer, component paint, tank wall paint
Used in containers: coatings for the inner and outer walls of food tanks, anticorrosive coatings for the inner and outer walls of storage tanks, and anticorrosive coatings for pressure tanks
Used in factory equipment: equipment, pipeline anticorrosive coating, refrigerator, washing machine outer coating, electrical equipment insulation coating
Application in civil construction: anticorrosive coatings for bridges, anticorrosive coatings for steel structures, impervious coatings for hydration products, floor coatings, decorative coatings, functional coatings, steel mesh cement gates
Applied to ships: coatings for inner walls of bottom warehouses, coatings for marine containers, anticorrosive coatings for steel parts
Used in other: powder coatings for steel furniture, powder coatings for resistance elements, powder coatings for steel parts, valve body anti-corrosion, heavy anti-corrosion super wear-resistant ceramics, shielded vertical pipeline pumps, solar water heaters, solar panels, weapons
Composite materials field
Applications: FRP car shell, FRP floor, FRP tank truck, control system instrumentation electrical parts, display, automotive dry ignition coil, FRP parts, anti-skid steering wheel cover, epoxy local reinforcement material,
Used in factory equipment: FRP oxygen cylinders, FRP storage tanks, FRP containers, pipes, molds, propellers, loom arrows, aircraft honeycomb structural parts, hoods, rollers, shafts, installed foundation leveling, self-leveling floors, electromagnetic Coils, pilot valves, glass parts, FRP pump valves, electric carbon products, construction engineering components, mechanical transmission components
Application of insulation materials: copper clad sheet, glass steel sheet, tube, rod, transformer, relay, high voltage switch, insulator, transformer, resistor, cable head, electronic device, component sealing or encapsulation and plastic packaging, alarm, solid power supply , FBT flyback transformers, focusing potentiometers, ignition coils for motor vehicles such as motorcycles, automobiles, electronics, electrical components, light-emitting diodes, signal lights, fully enclosed batteries, motor packages, temperature transmitters, recorder heads, circuit board closures, Integrated circuits, discrete diodes, triodes, passive filters, structural packaging of LEDs, packaged solar panels, power components, IC regulators and solid state relays, coal mine safety inspection systems, intrinsically safe modules, auto-reclosers
Used in sporting goods: FRP helmets, rackets, golf clubs, fishing rods, bowling balls, sleds, surfboards, FRP rowing boats, sailing boats, racing cars, deck chairs, hockey sticks
Used in other: aircraft fuselage, helicopter spiral blades, wind turbine blades, medical instruments, surgical handles, pacemakers, crafts jewelry, valve seals, hydraulic construction engineering, electroluminescent screens, concrete anti-wear layer , Insulation materials, animal models, space vehicles, ship tail shafts, rudder shafts, chemical wood, tower reinforcement, magnetic levitation train tracks, solar battery musical instruments, epoxy decorations, fiberglass reinforced plastic tent poles, knife handles, windows, furniture, pumps , Crutches, graphics cards, infrared filters, digital displays, matrix radiators, light emitting diodes and photodiodes, laboratory countertops, simulation trees, prefabricated millstone roads, bridges and pavements
Adhesive field
Application: Fast curing tough epoxy resin adhesive at room temperature, conductive adhesive, room temperature curing electrostatic flocking adhesive, optical structural adhesive, shuffleboard adhesive, chemical anchoring adhesive, high functionalization of silk, artificial flower, magnetic writing Board, car repair glue, stone glue, etc.
Application of toughened epoxy resin in adhesive
Polymer alloy adhesives based on toughened epoxy resins and functional fillers and curing agents overcome their shortcomings such as brittleness, impact resistance, and poor heat resistance. It has been widely used in machinery, electronics, electrical appliances, aerospace, aviation, coatings, bonding and other fields, and is known as universal structural adhesive.
1.Selection of curing system
Curing agents for epoxy resins include amines and acid anhydrides. Generally, amines are the main curing agents, and acid anhydrides are commonly used for electrical properties. Take imidazoles as accelerators.
Primary amines and secondary amines contain active hydrogen atoms, which can easily undergo nucleophilic addition reaction with epoxy groups to cross-link and cure epoxy resins. The curing process can be divided into three stages:
1) Primary amine reacts with epoxy resin to form macromolecules with secondary amine groups
2) The secondary amine group reacts with another epoxy group to form a larger molecule containing a tertiary amine group.
3) The remaining amine group, hydroxyl group and epoxy group react
The anhydride is ring-opened under the action of the hydroxyl group of the epoxy resin, a trace of water, and a hydroxyl-containing compound, and the generated carboxyl group is added to the epoxy group to obtain an ester group. The etherification reaction of the oxygen ring-opening occurs. In this way, the ring-opening, esterification, and etherification are repeated repeatedly until the epoxy resin is crosslinked and cured, which is the curing mechanism of the acid anhydride.
Imidazole is a five-membered ring containing two nitrogen atoms. One nitrogen atom constitutes a secondary amine and the other nitrogen atom constitutes a tertiary amine. It can be used as both a curing agent for epoxy resins and an accelerator for curing epoxy resins. The epoxy resin can be cured at medium temperature, but it has excellent heat resistance and mechanical properties, which is comparable to that of arylamine curing agents, but it is slightly inferior to medium resistance and humidity and heat aging resistance.
The molecule of the imidazole curing agent contains a secondary amine group and a tertiary amine group. The curing of the epoxy resin can be divided into two steps. Homopolymerization and curing reaction of epoxy resin have two exothermic peaks. They are 60 ° C and 1110 ° C. In order to improve its resistance to humidity and heat aging. A small amount of aromatic amine can be added.
2. Selection of filler
The heat resistance of the adhesive is not only related to the type, variety and molecular structure of the system's base polymer, vulcanizing crosslinker and other components, but also has a close relationship with the heat-resistant filler used in the system. Properly incorporating heat-resistant fillers into a formulation often results in a significant improvement in the heat resistance of the system.
Commonly used heat-resistant fillers include surface-modified gas phase method Si02, surface-treated Zn0, Fe203, and Al2O3. The surface-treated filler can significantly improve its heat resistance, for example, the silicone rubber system using white carbon black treated with (MeSi) 2NH as a filler. Even after being exposed to 250 for 48hr, the tensile strength is 9.3Mpa and the elongation is 335%. If the same kind of white carbon black without surface treatment is used,
Filled with the same silicone rubber system. After heat aging under the same conditions as above, its tensile strength and elongation were 6.6Mpa and 228%, respectively. visible. The improvement of heat-resistant performance of silicone rubber by heat-resistant filler is very significant.
All kinds of carbon black, nano-scale calcium carbonate, titanium dioxide, etc. It has the functions of strengthening, improving various physical properties, thickening, reducing cost, coloring and so on. Filler pairs reduce product shrinkage. Reduce internal stress. Improving overall performance is of great significance. For example, quartz powder can improve the hardness of the adhesive layer and the flowability of the potting compound; silicon micropowder can improve the bonding strength but the storage period will be shorter: adding a small amount of zinc chromate can improve the resistance to humidity and heat and salt spray: adding 325 mesh glass flake Has excellent corrosion resistance and water resistance; adding calcium sulfate whiskers has obvious toughening and strengthening effects, improving heat resistance and boiling water resistance, flame retardants, antimony trioxide to increase oxygen index, 264 antioxidants, prolonged Cured product life.
3.Polymer alloy repair material
Belzona Molecular Corporation was established in the United States in 1952. It is the first multinational institution dedicated to the research, development and production of polymer repair materials for industrial equipment corrosion, wear, aging and other problems. The polymer alloy repair agents produced by it are first applied after chemical equipment corrosion Repair. German TipTop company's products have always been the world leader in the application of belt maintenance. It is the world's largest manufacturer of cold and hot vulcanized rubber materials. Its products are: cold vulcanized adhesive materials and hot vulcanized adhesive materials required for rubber bonding, PvC adhesives, roller lagging materials and tools and equipment, conveyor belt repair materials and so on. Other products such as Devcon and E-wood have similar products. It refers to a composite adhesive material (also called repair agent, also known as adhesive coating agent) composed of high-molecular polymer and special functional fillers (such as graphite, molybdenum disulfide, metal powder, ceramic powder and fibers). The new material can achieve high bonding force, excellent corrosion resistance, wear resistance and high compressive strength. It also has good sealing performance, moisture resistance and insulation properties. Therefore, it is widely used in the field of equipment maintenance in industrial sectors such as machinery, construction, electronics, light industry, petroleum, chemical industry, ships, and aviation. On the one hand, it can be directly used as a new connection method other than riveting, welding, and screwing; Can wear, crack, scratch, corrode, erode, oversize, cast defects, etc. on any equipment. Repair in the shortest time. Polymer alloy repair agent is also known as "cold welding" or "industrial doctor", it can repair various cracks, scratches, oversize, casting defects, etc. on parts, and can also be used as part wear and corrosion Dimensional recovery and pre-protective coating.
Polymers of polymer alloys are mainly formulated with toughened epoxy resins. Others such as modified acrylates and polyurethanes can also be used as adhesive materials. The above polymers can also be modified to give materials new characteristic. And the addition of different functional fillers. The material is provided with functions such as electrical conductivity, thermal conductivity, magnetic permeability, temperature resistance, and heat insulation, and has no heat-affected zone and deformation on the part. It is easy to use and can be heated or pressurized. Operation at room temperature, no special equipment required, fast and easy repair, and on-site operation, universal, wear-resistant, anti-friction, corrosion-resistant, fast curing, wet surface repair, high and low temperature resistant, high strength . A variety of repair agents such as conductive and insulation potting, suitable for repairing metals, rubber, ceramics, concrete and other substances. Users can flexibly choose the corresponding product according to the material, operating temperature, pressure, chemical medium, downtime, field environment and other factors. It is widely used in marine shafts, pumps, and pipelines, and has the characteristics of simple operation, reliable performance, and shortening the dock repair cycle.
The key applications are as follows:
1) Repair of marine main engines and auxiliary engines;
2) Repair and sealing of heat exchangers and oil tank heating pipes;
3) Repair and regeneration of tail shaft, rudder pin, rudder pin seat hole and anti-corrosion and anti-wear treatment;
4) Repair and regeneration of propeller blades and resistance to cavitation corrosion;
5) Corrosion protection of deck and tank
4.Modified epoxy structural adhesive
1) Structural structural steel plate reinforcement. Anchor glue, anchor glue, fiber reinforced glue
2) Structural adhesive film for aerospace. Mushy. Cured at room temperature
4) Other industrial glues are resistant to environment, high and low temperature, vibration, aging, etc. 5. References (omitted)

Operation process of epoxy adhesive

Liquid-operating time
Operating time (also working time or pot life) is part of the curing time. After mixing, the resin / curing agent mixture is still liquid and working and suitable for the application. In order to ensure reliable bonding, all construction and positioning work should be done within the curing operation time.
2. Gel-enter curing
The mixture begins to enter the solidification phase (also known as the maturation phase), at which point it begins to gel or "mutate". At this time, the epoxy does not work for a long time, and it will lose its viscosity. Do not interfere with it at this stage. It will turn into a soft gel like hard rubber, you can press it with your thumb.
Because the mixture is only partially cured at this time, the newly used epoxy resin can still be chemically linked to it, so the untreated surface can still be bonded or reacted. Regardless, these capabilities are diminishing near-cured mixtures
3. Solid-final curing
The epoxy mixture reaches the stage of solidification and solidification, at which time it can be sanded and shaped. At this point you can't press it with your thumb. At this time, the epoxy resin has about 90% of the final reaction strength, so you can remove the fixing clips and leave it at room temperature to maintain a number of angels to continue curing.
At this time, the newly used epoxy resin cannot be chemically linked to it, so the epoxy surface must be properly pretreated, such as sanded, to obtain good bonding mechanical strength.

Precautions for epoxy adhesives

Epoxy resin adhesives are not toxic by themselves, but because of the addition of solvents and other toxic substances in the preparation process, many epoxy resins are "toxic". Therefore, the domestic epoxy resin industry is adopting water-based modification and avoiding additions. Maintain the "non-toxic" nature of the epoxy resin. It is necessary to change most epoxy resin coatings to be solvent-based coatings, which contain a large amount of volatile organic compounds (VOC), which are toxic and flammable, thus causing harm to the environment and human body.

Identification method of epoxy resin adhesive

As a high-performance, high-value-added glue type, epoxy adhesives are highly valued in the industry, but at the same time fake and inferior products are often patronized. Therefore, we can use the following chemical methods to identify.
The first method: dissolve the sample in sulfuric acid, add concentrated nitric acid, and pour into a large amount of sodium hydroxide solution. If it is yellow, it is generally epoxy resin.
Type 2: Drop 5 drops of concentrated nitric acid on the resin film, place the reaction into a test tube after leaving for a few minutes, add 6 ml of acetone, and then add 0.5 mol / L potassium hydroxide ethanol solution to make it alkaline. Red to purple indicates that the epoxy resin containing bisphenol A type is also intuitive;
The third method: take 0.5 ~ 1g of glue film or glue solution, 0.03g of p-phenylenediamine and 8ml of de-example water, boil for 8min, if it is epoxy resin, the solution will be pink.
The fourth method: take a small amount of film in a test tube, heat it to 240-250 degrees in a glycerin bath, and cover the test tube with a freshly prepared 5% nitroso ferricyanide and 5% morpholine aqueous solution. If the test paper is blue, it is proved to be epoxy resin. The expert from China Epoxy Resin Industry Association said that because cellulose did not react under such conditions.
The last method is as follows: Alkyd resin modified phenolic resin glue can be dissolved in a solvent containing potassium ethoxide and gelled after 3 hours. Water precipitation occurs only when epoxy resin is present, and this precipitate can be used as an analysis sample. If phenolic resin and amino resin are present at the same time, they can be distilled by steam in the presence of hydrochloric acid for 8hr, and then decomposed by water and extracted with a solvent (ethoxyethanol) to analyze the extract. In the case of an epoxy resin cured with an aromatic amine, the aromatic amine is decomposed into phenol upon heating. In this case, the phenol can be identified and confirmed.

Patented epoxy adhesive technology

Patented epoxy adhesive technology
1.Chromium-free, one-component, non-curing anti-corrosive sealant resistant to aviation fuel
2. A liquid epoxy composition for semiconductor packaging and use thereof
3. Hot melt adhesive composition with excellent heat resistance and cold resistance
4. Adhesives for building structures
5.Powderable crosslinkable fabric adhesive composition
6. Use of polymer dispersions as adhesives for sealing or coating compositions
7. Composite epoxy resin
8. Preparation of resin emulsion for thick film cathodic electrophoretic coating
9, color glaze glass adhesive
10. Aromatic amine epoxy curing agent and preparation method thereof
11. A liquid aromatic amine-cured epoxy potting material and preparation method thereof
12, instant plugging glue and application method
13, cold curing epoxy resin formula
14.Improved method for preparing improved resin
15.Light-curing adhesive
16. Ultraviolet curable adhesive composition and articles thereof
17.Epoxy adhesives containing dithiofluoramide adhesion promoter
18. Process for preparing highly substituted hydroxypropyl starch
19. Solvent-free epoxy-based adhesive for bonding semiconductor wafers and preparation method thereof
20.A high-grade heat-resistant flame-retardant potting impregnated resin glue
21. Flame retardant thermoplastic resin composition
22.Adhesive anchored steel-clad steel reinforcement bonding material and reinforcement method
23. Polyurethane coatings and adhesives containing monohydrocarbyl diene polymers and their epoxidized derivatives
24. An anti-flow paste epoxy adhesive
25. Adhesive composition and adhesive sheet
26. Curable organopolysiloxane composition with improved adhesion
27. Epoxy resin curing agent and preparation method thereof
28. Moisture activated adhesive composition
29. Adhesives based on lipid chemical reaction products
30. High temperature resistant adhesive for flexible printed circuits and preparation
31.Epoxy adhesives and copper foils and laminates using them
32. Radiation cross-linking and subsequent heat curing adhesives
33. High-strength gypsum bonding powder
34. Preparation method of high strength, high toughness and high wear resistance polyurethane-epoxy resin composite material
35. Structural adhesive composition with high temperature resistance
36. Amino polyfunctional epoxy resin heat-resistant building structure adhesive
37.Methods for improving the performance of pressure-sensitive adhesives at temperatures below 0 ° F
38. Protective agent for craft papyrus
39. Preparation method of bisphenol A epoxy acrylic diester
40. A new type of two-component insulation adhesive
41. Method for preparing phenolic epoxy resin by acetal method
42. Method for enhancing adhesion of polyimide to active metal
43.Preparation of epoxy two-component transparent soft encapsulant
44.Flock adhesive composition
45.One-component, non-flowing tough epoxy adhesive
46. A benzene-free low toxicity epoxy paint thinner
47. High-temperature-resistant instant plugging glue and its preparation method
48.Low viscosity epoxy resin composition
49. A chemical modification process of Tianjing gum and its products
50. Photopolymerizable composition with excellent adhesive properties, its product and preparation method
51. Room temperature curing high temperature resistant high strength and toughness epoxy structural adhesive and preparation method thereof
52. Curable structural epoxy paste adhesive at room temperature and manufacturing method thereof
53, epoxy resin mixture
54. Used as a binder for cathode electrolytic coatings
55.Solderable conductive composition with high adhesion strength
56. A resin composition and a method for manufacturing a laminate using the same

Other contents of epoxy adhesive

Epoxy adhesive reference formula [2] [1]
ingredient
Mass percentage
Ingredient description
Epoxy resin (E-44)
100
[2]
Dibutyl phthalate
10
acetone
60
Ethylenediamine
8

Corundum powder
Right amount
Porcelain powder
Right amount

IN OTHER LANGUAGES

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