The application of epoxy resin in construction mainly includes the following aspects: first, floor coating, second, building corrosion prevention, and third, structural strengthening. Regarding floor coating, the most commonly used film-forming substances are synthetic resin-based materials represented by epoxy resin. The coatings are generally divided into solvent-free, solvent-based and water-soluble types. Solvent-based system has the defects of solvent volatilization, small viscosity, low solids content, thin film, and easy to float color during construction, etc. However, the film-forming material has weak impact resistance. The solvent-free system can be adjusted to nearly 100% solids content and film thickness at one time because it does not contain inactive solvents, and there will be no Benard’s nest and floating color in construction; while the water-soluble clean wear-resistant floor coating has good adhesion to wet substrates. About building corrosion prevention, due to acid and alkali salts, organic solvents and other media, construction materials produce different degrees of various types of physical and chemical damage. This corrosion process is generally slow and short-term consequences are not obvious, but once the harm caused is quite serious. In the construction of epoxy resin corrosion prevention, commonly used material products include resin mastic, resin mortar, glass fiber reinforced plastic and resin glass scale. Resin cement, resin mortar and resin glass scale are made by adding curing agent, toughening agent (some materials need to add accelerator or diluent), powder, fine aggregate, coarse aggregate, and treated glass scale with resin as cementing material. Regarding structural strengthening, concrete and reinforced concrete structures often suffer different damages and affect their service life due to various factors during use. Epoxy adhesive has superior performance and more ways of modification, which is mostly used for bonding and repairing of concrete components, as well as bridge engineering, airstrip, highway construction, concrete structure crack reinforcement or anti-seepage plugging grouting, etc.
Synthesis and application of high-strength epoxy resin for structural adhesive.
With the development of construction industry, construction structural adhesive has now become a new type of structural member bonding material and decorative repair materials in building construction. Its main uses are: bonded steel reinforcement of various components, repairing bridges, repairing beam and column defects of old plants, column extension, cantilever beam bonding, cement pile head extension, bull leg bonding, etc. Since epoxy resin has the advantages of easy operation, high strength after curing, environmental aging resistance and moderate price, so the commonly used construction structural adhesive is epoxy resin adhesive. The epoxy resin adhesive used in the construction industry should have the following characteristics:
- High shear strength, compression strength and tensile strength.
- It can be used under -40～80°C for a long time.
- Excellent humidity and heat aging resistance, excellent water resistance.
- Easy to operate and moderate curing speed.
In order to meet the above performance, a suitable formula is necessary. The general formula is: epoxy resin, toughening agent, diluent, filler, curing agent, curing accelerator, etc. Drawing on the experience of using polyurethane modified epoxy resin in foreign construction adhesives, we have successfully developed a kind of tough epoxy resin for construction adhesives – polyurethane modified epoxy resin. The specific synthesis conditions are as follows:
Main raw materials:
YQXPOLYMER
- II. The synthesis process
Preheat the epoxy resin to 60°C and add the catalyst then slowly add the polyurethane resin. After 4 hours reaction at 80-90°C under the protection of nitrogen, release the material.
III. Analysis of results
The rotational viscosity of this polyurethane modified epoxy resin at 60°C is: 1800 centipoise, epoxy value: 0.37. The color is light yellow and soluble in solvents such as toluene, butanone, n-butanol and ethyl acetate. In addition, it has good miscibility with high melting point epoxy resin.
Polyurethane modified epoxy resin construction adhesive combines the advantages of good operability, high strength of epoxy resin and good toughness of polyurethane resin, which is a new generation of construction adhesive in China. The normal temperature curing epoxy adhesive is the island structure, and polyurethane epoxy resin interpenetrating network structure. The new formulation does not need to use polysulfide rubber with bad odor and other toughening agents. In addition, the cost is slightly lower than the building structure epoxy adhesive containing polysulfide rubber, and it has excellent strength and aging resistance.
More YQXPOLYMER Epoxy Resins information, please contact us via email: sales@yqxpolymer.com , or voice to us at: +86-28-8411-1861.
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