A class ofan adhesive。Generally, the stress that the bonded joint can bear should be equal to the strength of the adherend itself. The adhesive itself has excellent heat resistance, medium resistance, atmospheric aging resistance, vibration fatigue resistance, low creep and high endurance strength.
Description: A class ofan adhesive。Generally, the stress that the bonded joint can bear should be equal to the strength of the adherend itself. The adhesive itself has excellent heat resistance, medium resistance, atmospheric aging resistance, vibration fatigue resistance, low creep and high endurance strength.Most of them have a three-way cross-linked structureThermosetting resinAs the main body, equipped withThermoplastic resinOr rubber typeToughening agentform.It is mainly used in modern industrial technology departments such as machinery manufacturing and manufacturing of high-speed vehicles (such as aircraft, rockets, missiles).The main varieties are epoxy nylon, epoxy butyronitrile, epoxy (cured with aromatic amine), phenolic butyronitrile, phenolic epoxypolyimide、PolybenzimidazoleEtc.
form
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Structural adhesive is mostly used for bonding engineering structural parts, also known asengineering/Structural adhesive is a kind of adhesive that can withstand many stress environmental effects within the rated time without being damaged.Structural adhesives are mainly used for bonding stressed structural parts, which can withstand large loads, still have good mechanical strength at operating temperatures above normal temperature, and are resistant to chemicals and other media, chemicals and other media, aging resistance and other characteristics, so they are widely used in industry.It is usually made with this adhesive during the service lifeAdhesive jointThe bearing capacity of the structural adhesive connector shall be equivalent to that of the adhesive. In all cases, the durability of the structural adhesive connector shall be longer than the expected service life of the structure.
Structural adhesive generallyThermosetting resinFor adhesiveThermoplastic resinOr elastomer is used as toughening agent, with curing agent and other components, and some are also added with filler, solvent, diluent, coupling agent, curing accelerator, corrosion inhibitor and thermal oxidant.The properties of adhesives mainly depend on the structure, proportion and compatibility of these components.
Engineering/structural adhesives include epoxy adhesive, polyurethane adhesive, acrylate adhesive, anaerobic adhesiveOrganic silica gelThe above adhesives are mostly reactive and can be cured by chemical reaction at room temperature without solvent.There is no consensus on the definition, classification and evaluation standards of structural adhesives at home and abroad, and the views of various industries are also different.When people classify and define structural adhesive and non structural adhesive, they generally refer to the adhesive used in the bonding of components at the strength bearing part as structural adhesive, and the adhesive used in the bonding of components at the strength not bearing part as non structural adhesive.However, since the same adhesive can be used in the parts subject to strength, it can also be used in the parts not subject to strength. Therefore, the more strict method is to define and classify the adhesive from its performance.The American aviation structural adhesive standard MMM-A-132 divides structural adhesives into four types according to the requirements of flight speeds at different Mach numbers for heat resistance, and specifies their strength indicators such as shear, fatigue, creep, aging, and T-peel.The corresponding flight speed of Type I is below Mach 1, and the strength index at room temperature and 82 ℃ is specified;Type II corresponds to Mach 1~2, which specifies the strength index at room temperature and 149 ℃;Type III and IV correspond to Mach 2 or above to Mach 3 or so, and specify strength indexes at room temperature, 149 ℃ and 260 ℃.The last three types areSupersonic aircraftHigh temperature resistant structural adhesive used.[1]
classification
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Classification according to main components
Structural adhesives can be divided intoEpoxy resin adhesive、Acrylate adhesive, anaerobic gel and organic silica gel, etc.According to the supply status of adhesive, it can be divided into liquid adhesive, paste adhesive, ribbon adhesive, powder adhesive and film adhesive.
Classification by strength
According to different strengths, Type I can be divided into three levels, as follows: Level I is used for bonding of main load-bearing structures, which is structural adhesive;The second level is used for bonding the secondary stressed structure, which is a quasi structural adhesive;Tertiary pairpeel strength No requirements, it shall be a non structural adhesive.There is no national standard for the definition and classification of structural adhesives in China. Generally, structural adhesives are classified into high strength, high toughness, medium strength and medium toughness according to the adhesive acceptance and adhesive strength: the steel steel shear strength of adhesive for main load-bearing structures is 25MPa, the tensile strength is 33MPa, and the non-uniform tensile strength is 40KN/m;The shear strength of the adhesive used for the secondary stressed structure is 17~25MPa, and the uneven tearing strength is 25~50KN/m.
Classification according to curing temperature
For example, epoxy structural adhesive can be divided into high temperaturesolidification, medium temperature curing, room temperature curing and low temperature curing: high temperature curing epoxy structural adhesive has high temperature, toughness, heat resistance, etc., and is mostly used for bonding main load-bearing structures;The medium temperature curing epoxy structural adhesive is mainly developed to meet the needs of the aircraft industry. Since the aluminum alloy begins to show the tendency of grain boundary corrosion at 120 ℃ or above, and it intensifies with the increase of temperature, the strength and toughness of the aluminum alloy will decline after the grain boundary corrosion, so the curing condition of the adhesive for bonding aluminum alloy is required not to exceed 130 ℃ for 4h;Room temperature curing epoxy structural adhesive is more widely used and more important in the field of civil construction. It is one of the main varieties of building structural adhesive;Low temperature curingEpoxy adhesiveIt is a new type of glue developed in recent years to meet the needs of low-temperature construction in winter. It can be constructed and solidified at 0 ℃, or even below - 10 ℃.Generally, the curing temperature is classified as:
Group 1, curing temperature lower than 40 ℃
2 groups, curing temperature 40~80 ℃
3 groups, curing temperature 81~120 ℃
4 groups, curing temperature: 121~180 ℃
5 groups, curing temperature higher than 180 ℃
Classification according to heat resistance
Structural adhesives can also be divided into general type (80 ℃), high temperature resistant type (150 ℃) and medium temperature resistant type (between the former).If classified according to service temperature:
Class I, long-term use at - 55~80 ℃
Class II, - 55~150 ℃ long-term use
Class III, - 55~220 ℃ long-term use
Class IV, - 55~220 ℃ for long-term use or 300 ℃ for short-term use
Classification by service performance
In the aerospace industry, they are generally classified into:
(1) Plate to plate glue
(2) Panel glue
(3) Core strip adhesive
(4) Styrofoam
(5) Primer
(6) Repair adhesive
(7) Spot welding adhesive
advantage
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Non structural adhesive has low strength and poor durability. It can only be used for bonding, sealing and fixing of ordinary and temporary properties, and cannot be used for bonding structural parts.
Structural adhesiveHigh strength, anti stripping, impact resistance, simple construction process.It is used for bonding metal, ceramics, plastics, rubber, wood and other similar materials or different materials.It can partially replace the traditional connection forms such as welding, riveting and bolt connection.The stress distribution on the joint surface is uniform, and there is no thermal effect and deformation on the parts.
purpose
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Structural adhesive is widely used in engineering, mainly for reinforcement, anchoring, bonding and repair of components;Such as sticking steel,Viscous carbon fiber, planting reinforcement, crack reinforcement, sealing, hole repair, spike pasting, surface protection, concrete bonding, etc.
Usage of structural adhesive
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Different types of structural adhesives use different methods, but generally the same.
1. Surface treatment: roughen the parts to be repaired or to be bonded, and then clean them with cleaning agent.
2. Preparation: Mix the two components A and B evenly according to the mass ratio A: B=4:1 or the volume ratio 3:1, and use up within the specified operation time limit.
3. Coating: evenly apply the prepared adhesive on the surface of the object to be adhered.
4. Curing: It can be put into use after curing at 20~25 ℃ for 24 hours or curing at 20~25 ℃ for 2 hours+80 ℃ for 2 hours. If the temperature is low, heating or extending the curing time should be used to promote curing.[2]
Packaging and storage
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1. Two component, 250g/set, 16 sets/box.
2. Store tightly in a cool and dry place with a shelf life of 2 years.
an adhesive
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It is a kind of material with good adhesion performance.It is used to connect objects through adhesion and cohesion.
characteristic
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The organic or inorganic, natural or synthetic substances that can connect the same kind or two or more homogeneous or heterogeneous products (or materials) together and have sufficient strength after curing are collectively referred to as adhesives or adhesives, adhesives, and conventionally referred to as glue.
NaturalPolymer compound(starch, animal skin glue, bone glue, natural rubber, etc.), synthetic polymer compounds (epoxy resin, phenolic resinUrea formaldehyde resin, polyurethane and other thermosetting resins andPolyvinyl acetal、Perchloroethylene resinIsoplastics, andNeoprene，Nitrile rubberetc.synthetic rubber）, or inorganic compounds (silicate, phosphate, etc.).According to the use requirements, curing agent, accelerator, reinforcing agent, olefin releasing agent, filler, etc. are often mixed into the adhesive.Classified by use, it can also separate warm glue, sealant, structural glue, etc.According to the use process, there are room temperature curing adhesive, pressure sensitive adhesive, etc.The adhesive can be used to connect heterogeneous materials and sheet materials, and the stress distribution at the bonding part is uniform.Epoxy resin, neoprene and sealant are commonly used in container manufacturing and repair.
In recent years, the organic adhesive has been more and more widely used, and the bonding technology has also developed maturely, and has become one of the three contemporary connection technologies of bonding, welding and mechanical connection.[3]
