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    Home > Coatings News > Paints and Coatings Market > Brief introduction and classification of curing agents for epoxy resin

    Brief introduction and classification of curing agents for epoxy resin

    • Last Update: 2020-03-04
    • Source: Internet
    • Author: User
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    Curing agent, also known as hardener, curing agent or modifier, is a kind of substance or mixture that promotes or controls curing reaction Resin curing is a process of irreversible change of thermosetting resin through condensation, closed-loop, addition or catalysis Curing is completed by adding curing (cross-linking) agent Classification of curing agents for epoxy resin (1) basic and acid curing agents: ① basic curing agents include aliphatic diamines and polyamines, aromatic polyamines, other nitrogen compounds and modified aliphatic amines (2) acid curing agents include organic acids, anhydrides, boron trifluoride and their complexes (2) addition curing agent and catalytic curing agent: ① addition curing agent and epoxy group react to form a part of the chain segment of the curing product, and the linear molecules are crosslinked into shape structural molecules through gradual polymerization, which is also called melon type curing agent Such as primary amines, polysulfides, polyphenols, low molecular polyamides, organic acids and anhydrides, and low condensation curing agents (2) the curing agent of catalytic type only initiates the epoxy resin After the epoxy group is opened, the epoxy resin itself is polymerized into a network structure to form a homopolymer with ether bond as the main structure, while the curing agent itself does not produce cross-linking reaction Such as tertiary amine, imidazole, dicyandiamine, boron trifluoride complex, stannous chloride, stannous isooctanoate and stannous octanoate Introduction of common curing agents for epoxy resin: epoxy resin curing products have excellent mechanical properties, electrical properties, chemical resistance, so they are widely used Curing agent is one of the necessary raw materials for the curing of epoxy resin, otherwise the epoxy resin will not cure In order to meet the requirements of various application fields, the corresponding curing agent should be used There are many kinds of curing agents, which are introduced as follows: fatty polyamine ethylenediamine EDA h2nch2ch2nh2 molecular weight 60 active hydrogen equivalent 15 colorless liquid 6-8 parts per 100 standard resin performance: toxic, pungent odor, high volatility, low viscosity, fast curing at room temperature Used for bonding, pouring and coating With the increase of molecular weight, viscosity, volatility, toxicity and performance of these amines increased But they have large heat release and short application period Generally speaking, the larger the molecular weight is, the smaller the influence of the coordination is Long term exposure to aliphatic polyamines can cause dermatitis, and their steam toxicity is very strong, so great attention should be paid to the operation Diethylenetriamine, deta h2nc2h4nhc2h4nh2, molecular weight 103, active hydrogen equivalent, 20.6 colorless liquid, 8-11 parts for every 100 standard resins Curing: 20 ℃ for 2 hours + 100 ℃ for 30 minutes or 20 ℃ for 4 days Performance: the application period is 50g, 25 ℃ and 45min, the hot deformation temperature is 95-124 ℃, the bending strength is 1000-1160kg / cm2, the compressive strength is 1120kg / cm2, the tensile strength is 780kg / cm2, the elongation is 5.5%, and the impact strength is 0.4-foot-pound/inch Rockwell hardness is 99-108 Dielectric constant (50 Hz, 23 ℃) 4.1 power factor (50 Hz, 23 ℃) 0.009 volume resistance 2x1016 Ω - cm room temperature curing, high toxicity, high heat release, short application period Triethylenetetramine TetA h2nc2h4nhc2h4nhc2h4nh2 molecular weight 146 active hydrogen equivalent 24.3 colorless viscous liquid is cured with 10-13 parts per 100 standard resins: 20 ℃ 2 hours + 100 ℃ 30 minutes or 20 ℃ 7 days Performance: application period: 50g, 25 ℃, 45min, hot deformation temperature: 98-124 ℃, bending strength: 950-1200kg / cm2, compressive strength: 1100kg / cm2, tensile strength: 780kg / cm2, elongation: 4.4%, impact strength: 0.4-foot-pound/inch, Rockwell hardness: 99-106 Room temperature curing, toxicity is slightly lower than diethylenetriamine, heat release is large and application period is short Tetraethylene pentamine TEPA h2nc2h4 (nhc2h4) 3nh2 molecular weight 189 active hydrogen equivalent 27 brown liquid 11-15 parts per 100 standard resin performance is the same as above PEPA h2nc2h4 (nhc2h4) NH2 light yellow liquid uses 14-15 phr for every 100 standard resins It has low toxicity, low volatility, long application period and low price Dpta, dpta, H2n (CH2) 3nh (CH2) 3nh2, molecular weight 131, active hydrogen equivalent 26, light yellow liquid, 12-15 parts for every 100 standard resins, the performance is the same as that of TetA Dimethylaminopropylamine DMAPA (CH3) 2n (CH2) 3nh2 low viscosity transparent liquid with 4-7 parts per 100 standard resins is highly toxic It has two reactions of curing and catalysis It has good adhesion performance, good flexibility and long application period Deapa (C2H5) 2n (CH2) 3nh2 molecular weight 130 active hydrogen equivalent 65 low viscosity transparent liquid is cured with 4-8 parts per 100 standard resins at 60-70 ℃ for 4 hours Performance: application period: 50g, 25 ℃, 4h, hot deformation temperature: 78-94 ℃, compressive strength: 920-1050kg / cm2, tensile strength: 480-640kg / cm2, impact strength: 0.2-lb / inch, Rockwell hardness: 90-98 The dielectric constant (50 Hz, 23 ℃) is 3.75, and the power factor (50 Hz, 23 ℃) is 0.007 Trimethylhexamethylenediamine TMD (H2n) 2 (c6h9) (CH3) 3 is a colorless liquid, which has a long application period and little toxicity Each 100 standard resins are cured with 21 parts: 80 ℃ for 1 hour + 150 ℃ for 2 hours Performance: suitable for 400g, 25 ℃ for 50min or 50 ℃ for 10min, martin heat resistant for 92 ℃, bending strength for 1150Kg / cm2, impact strength for 20kg cm / cm2 TG δ 0.0009 (23 ℃, 100C / s), surface resistance for 5.4x101Ω (300V), volume resistance for 9x1015 Ω Cm (300V), medium temperature curing and low temperature performance The molecular formula of amine248, a modified product of diethylenetriamine H2n (CH2) 6nh (CH2) 6nh2, is unknown The viscosity of transparent liquid is 25 ℃ 1000-3000cps Every 100 standard resins are cured at 4-8 parts at room temperature - 100 ℃ It is less toxic and flexible Hexamine adducts ch-2, l2505 molecular formula unknown amine value 160-210 low viscosity transparent liquid 65 parts per 100 standard resin, 400-500 low viscosity transparent liquid 60 parts per 100 standard resin, hexamine HDA H2n (CH2) 6nh2 molecular weight 116 active hydrogen equivalent 29 colorless sheet crystal melting point 42 ℃ Every 100 standard resins with 12-15 toxic, can cure at room temperature but not good The application period is short Trimethylenediamine 158 / 100 standard resin cured with 20-25 parts: 20 ℃ for 2 hours + 100 ℃ for 30 minutes or 20 ℃ for 7 days Performance: application period: 50g, 25 ℃, 45min, hot deformation temperature: 105 ℃, bending strength: 1150Kg / cm2, tensile strength: 650kg / cm2, elongation: 4.4%, impact strength: 0.4ft-lb / inch Dielectric constant (50 Hz, 23 ℃) 4.0 power factor (50 Hz, 23 ℃) 0.001 volume resistance 9x1015 Ω - cm diethylamine DEA HN (C2H5) 2 molecular weight 73 active hydrogen equivalent 73 colorless liquid 12 parts for 100 standard resin has two reactions of curing and catalysis Polyether diamine H2n (CH2) no (CH2CH2O) mnh2
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