Modification method of epoxy resin

1, liquidity control:
a. de-adhesive: epoxy resin material said that the required viscosity varies greatly according to the use, such as coating, lining, casting and impregnation and other uses, requires viscosity than liquid BA resin is lower, of course, the viscosity requirements of each use are not the same, high-viscosity epoxy resin can be added to control viscosity, diluent can be divided into inactive diluents and active diluents.

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typical active thinners are listed as follows:
zhengbutyl shrinkage glycelor ether BGE
ene propyl shrinkage glycelor ether AGE
2-ethyl hetase glycelor ether EHAGE
styrene oxide SO
styrene shrinkage glyceloride Ether PGE
methylphenol shrinkage glyceline ether CGE
to butyl benzene shrink glyceline ether BPGE
methyl acrylic shrink glyceride glyceride glycerides
tri-grade pyric acid shrink glycerides
two shrink glycerides DGE.
Glycerol and Shrinking Glyceroe PEGGE
Polypropylene Glycol Glycerides PPGGE
Butyl Glycol glycol glycerides BDGE
Ii Shrinking Glycerol DGA
Triamolphyl Propane Triple Shrinking Glyceline Ether TMP GE
propylene triglyceride glyceline ether GGE
b. added viscosity: the use of large molecular weight or the addition of inorganic filler method can make liquid viscosity increase adhesion, inorganic adhesive in the best effect is tactivagent (a type of filler), the poor effect of increased adhesion is ordinary inorganic filler;
c. Tactilability: The so-called tentacles refer to the dispersion behavior of dispersed particles that easily form a condensed structure - when the viscosity of the mucus of the dispersed fluid decreases when continuous or repeated force is added, the flow increases as a phenomenon, which is caused by stirring to destroy the internal condensing structure, and is roughly restored when the external forces cancel the static. Adding fillers to increase the viscosity at the same time will bring some tentacles, and those with a large impact effect of additives into the tentacles, of course, the tentacles usually also have a high viscosity, the smaller the particle size, the larger the aspect ratio (aspect ratio) the better the effect . The representatives of tactile agents are talcum powder, asbestos, silicon micro-powder, gas-phase silicon dioxide and gel-containing aluminum silicate/organic compounds;
2, "alloy" modified:
a. For the following purposes, epoxy materials are often required to be soft:
. Improved impact strength: improved impact strength due to increased fracture elongation;
. Improved heat-resistant shock resistance: sharp changes in temperature can produce deformation, often resulting in cracking, material with softness can improve the absorption of deformation;
: Softness can reduce the internal stress caused by curing contraction, thereby increasing the bonding (adhesion) to the substrate;
b. Plasticizer type: can be divided into reaction type (reaction plasticizer) and non-reactive type (easy to produce material fog bloming problem), wherein the reaction type can do the following subdivision:
, epoxy: monociroxide,
polyoxidants; Non-epoxy: polythionols, polyxaccharides, polyols, aminomethylate prepolymers
. Typical reactive plasticizers:
monocyclic oxides: cyclocyclic phenols
Additions to BPA-alkane oxides d-shrink glyceride ether (side-chain epoxy), polymer fatty acid additions of BPA di-shrink glyceline ether, polymeric fatty acid polyshedr glycerides (suitable for all curing agents)
Polyols: polypropylene glycol Polytehydrofuran, end hydroxyl polyester (suitable for pyridine, Louisian acid)
Polysulfulphur: polythionolide (suitable for polyamines, polyamides, serotonin)
polycyclic acids: polymer fatty acids (suitable for acids, serotonin)
Acetate: aminomethylate pre-polymer (suitable for polyamines, polyamides)
c. plasticization effect: generally in the plasticization effect at the same time, will lose some of the curing of some other material or water absorption rate and other indicators, need to be considered comprehensively;
3, Rubber mixture correction:
rubber modifier is the dispersion of rubber particles on a cured epoxy substation. This modified does not significantly reduce the Tg (HDT) of the cured resin as the alloy modifier, but rather makes the curing strong toughening, which is technically complex, but practically extremely important:
a. modified theory: the following the thermoplastic resin theory explains the structure of the rubber modified epoxy material:
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. Rubber particles with good toughness bonding type: rubber particles and resin bonding good conditions, by the rubber particles elongation of the stretch stress to suppress the expansion of cracks, while absorbing part of the impact energy;
. . easy to crack rubber particles: rubber particles with low stretch strength, and the determination temperature below Tg in the case of rubber particle destruction;
rubber particles with poor adhesion: crack steering interface expands when rubber particles are badly bonded to resin;
is modified with rubber, The conditions for obtaining good results can be summarized as follows: the size of rubber particles is appropriate (0.1 to 0.2u), rubber particles have an appropriate
elastic mould, rubber particles are bonded to the base resin;
b. Factors affecting the effect of the modified effect: the formation of
solid rubber particles;
, the bonding of rubber particles and substation resins;
c. Effect of change: rubber mixture modified method, both to the desired direction of performance, but also to the desired direction of performance
, in general, strong toughness, impact strength, adhesion is improved, and heat resistance
(HDT), stretch strength, resistance is reduced; Epoxy resins also use fillers for a combination of modified mechanical, thermal or electrical properties. In order to obtain good modified effect, it is important to give full consideration to the bonding of fillers and substation resins, and the use of even agent treatment is an effective method to improve bonding.
a. Types and uses of fillers: there are many types of fillers, the adaptability of fillers not only depends on the chemical composition of fillers, but also related to their shape and particle size, adding fillers can not improve all performance, often improve the first performance, other performance correspondingly decreased;
b. Commonly used inorganic fillers: asbestos, alumina, green slope stone, kaolin clay, volcanic ash, carbon black, asbestos ink, silicon powder, calcium silicate, diatomite, magnesium oxide, titanium oxide, iron oxide, magnesium hydroxide, aluminum hydroxide, slate powder, mica, quartz powder, molten silica, boron carbide, calcium carbonate, magnesium carbonate, talc, long stone powder, niobium desulfurization, heavy crystal, zircon, white herring, mica, Shoushishan clay, water-free gypsum, etc.
c. Surface treatment with a coupled agent: the available coupled agents are silane and titanium, there are some differences in the treatment effect, the method of treating fillers with a coupled agent has a direct treatment of fillers, bar-coupled agents added to the epoxy filler mixture;
. d. The modified effect of filler:
improve mechanical performance, stretch strength, bending strength, impact strength, dimensional stability, wear resistance, hardness;
. Improve thermal performance: thermal aging, HDT, high temperature characteristics, reduce thermal expansion coefficient, thermal conductivity, give flame retardant (delayed combustion, self-extinguishing, improve ignition point);
. Improve electrical performance: arc resistance, high temperature insulation, high temperature dielectic properties;
. Improve drug resistance: acid resistance, alkalinity, water resistance, solvent resistance;
improved operating characteristics: increased viscosity, touch change, reduced curing heating, reduced curing shrinkage.
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