Coating classification: Waterborne UV curable resin

The key points are: UV curing technology is a kind of clean and environmental protection "green technology", which has the characteristics of excellent processing performance, no environmental pollution and high function It can be divided into visible curing and UV curing according to the different absorption wavelength Among them, UV curing belongs to radiation curing, its principle is to use UV to initiate the active liquid material, so that it can quickly decompose into free radicals or cations, and then initiate the unsaturated bond polymerization reaction, so that the material can be cured completely The traditional UV curing system uses active diluent to adjust its rheological properties, which not only makes the material have irritant gas Paint knowledge how about Akzo Nobel Powder Coating Recommended introduction: powder coating is a kind of coating with different form from general coating, which is in powder form It is a new type of coating, because of its own advantages and more and more known by people Let's introduce Akzo Nobel Powder coating Akzo Nobel Powder coating is a cost-effective coating solution, which can be applied to different kinds of products After the treatment of static electricity and fire baking, a tough and durable coating surface will be formed, with the least impact on the environment Since the introduction of this technology, powder coating has been able to continue to maintain the Coating home news: UV curing technology is a clean and environmental protection "green technology", with excellent processing performance, no environmental pollution and high function It can be divided into visible curing and UV curing according to the different absorption wavelength Among them, UV curing belongs to radiation curing, its principle is to use UV to initiate the active liquid material, so that it can quickly decompose into free radicals or cations, and then initiate the unsaturated bond polymerization reaction, so that the material can be cured completely The traditional UV curing system uses active diluent to adjust its rheological properties, which not only makes the materials have pungent smell, but also has a negative impact on the physical and chemical properties of the film The water-based UV curing system (using water instead of active diluent) has many advantages: ① the rheological property is easy to control, so as to avoid the curing shrinkage caused by the use of active diluent to adjust the viscosity of the system; ② the final product has the characteristics of low VOC (organic volatile matter) emissions, low toxicity and low irritant odor; ③ the smoothness of the curing adhesive film is improved, and the adhesive is reduced The oligomer is a kind of water-borne dispersion with high Mr (relative molecular weight), but its viscosity is only related to the solid content, not to Mr (the oligomer with high Mr can be selected as its prepolymer, and the active diluent with low Mr need not be added), which solves the problem that the high hardness and high flexibility of UV curable coating can not be considered at the same time (this is also the advantage of water-borne UV technology over the traditional one) One of the characteristics of UV Technology) The combination of UV curing technology and water-based resin can achieve the goal of environmental protection and high efficiency, and its application field is constantly expanding 1 Water based UV curable resin water-based UV curable resin refers to the introduction of water-based groups or segments on the basis of traditional UV curable resin, so that the resin has certain hydrophilicity and water absorption There are two common synthesis methods of Waterborne UV curable resin: one is to introduce hydrophilic groups [such as up (unsaturated polyester) resin] into the molecular chain of traditional resin; the other is to react with acrylate to form waterborne acrylate oligomers [such as PUA (polyurethane acrylate), EA (epoxy acrylate), etc.] Waterborne UV curable resin has the advantages of no solvent odor, no poison, no pollution, convenient operation, easy cleaning of residual glue, high solid content and safe and convenient storage and transportation, which is the development direction of environmental protection and energy saving UV curable resin 1.1 the classification of water-based UV curing resin oligomer is an important part of water-based UV curing system Different from the traditional UV curable resin, the molecular structure of Waterborne UV curable resin matrix must contain hydrophilic group or hydrophilic chain segment, so that the polymer has certain water absorption According to different matrix resins, Waterborne UV curable oligomers can be divided into up, PUA and EA The comprehensive performance of PUA is relatively good, while the chemical stability of EA is relatively best Therefore, the selection of prepolymer has a great influence on the thickness, hardness and shear strength of the final cured film 1.1.1 UP resin is one of the earliest raw materials for UV curing coating Waterborne up is a kind of ionic copolyester which is made by introducing ionic structural units into the molecular chain of traditional up The existence of ionic groups not only endows up with good water solubility, but also endows it with excellent hydroscopicity and ionic conductivity The commonly used water-based modifiers are mainly volatile amines, sulfonates, etc (they can be used alone or in combination), which can produce or introduce bases on up (control the acid value or neutralization degree of up, and make different dispersion systems), so that the resin has good water solubility and water dispersion Satpute et al Added different proportions of MA (maleic anhydride) and PA (phthalic anhydride) into PG (propylene glycol), and made six kinds of up with different end carboxyl groups The results showed that when the ammonia was used as the emulsifier of UP, the coating had excellent stability The hardness, flexibility, water resistance, chemical stability and solvent resistance of the UP emulsion increased with the increase of MA content Jankowski et al Used sodium 3-hydroxy-1-propane sulfonate or sodium Dihydroxypropane sulfonate as sulfonate modifier, prepared a new type of water-borne UV curable resin containing absorbent sulfonic acid group by copolymerization The coating has high hardness and good adhesion to glass and metal substrate 1.1.2 PUA resin coating is characterized by good wear resistance, good flexibility, relatively high impact strength and tensile strength, excellent chemical corrosion resistance and excellent adhesion, which has been widely used in water-borne UV curing oligomer system After copolymerizing Pu (polyurethane) with acrylate (cheap, easy to prepare, full film and good glossiness) with excellent comprehensive performance and high price, the PUA resin has both advantages, and the corresponding use performance of UV curable water-based resin is improved obviously Tang Jincai et al Prepared WSPUA (waterborne UV solidified star shaped arm PUA), and emphatically discussed the influence of the soft segment of star PU arm on the properties of WSPUA emulsion and UV curing film Asif et al Prepared the corresponding UV curable resin with whpuas (waterborne hyperbranched PUA) as prepolymer The results show that TG (glass transition temperature) of cured whpuas is higher than that of cured eb2002, and the coating strength of the former is higher than that of the latter Rwei et al Studied the UV curing kinetics of two kinds of waterborne PUA [HDI (hexadiisocyanate acrylate) and hmdi (4,4 '- diisocyanate dicyclohexylmethane)] The results show that the steric resistance of cyclohexane in hmdi has a negative effect on the curing kinetics, so the curing rate constant of hmdi is always relatively low Modified Waterborne UV curable PUA can effectively overcome the shortcomings of traditional UV curable PUA, such as poor water resistance, poor flexibility and so on Yin Hailong and others introduced a variety of hydrophilic groups into the PUA chain segment to synthesize a multifunctional modified UV curable wpua (water-based PUA), and found that the comprehensive performance of the cured film of the modified product was improved The comprehensive properties of Waterborne UV curable PUA resin can be further improved by organosilicon nanocomposite modification The PUA nanocomposites containing alumina and SiO2 were synthesized by aqueous UV polymerization with yanjiagu 819 as photoinitiator The results show that the introduction of alumina and SiO2 nanoparticles can effectively improve the hardness of PUA coating without affecting the adhesion between the coating and the adherend Qiu et al First synthesized the waterborne UV curable PUA oligomers by in-situ method Then, the water borne UV cured PUA/SiO2 oligomers were prepared by sol-gel method with different TEOS (four ethoxy silane) and GLYMO (3- glycidyl propyl trimethoxy silane) as coupling agents The results show that the composite is expected to be widely used in high performance UV curable resin Chu mixed the water-based PUA and the water-based EA resin, and then UV cured them The UV curing film of the blend has good comprehensive properties (such as compatibility, curing rate, optical properties and mechanical properties), and its application prospect in coatings, varnishes and inks is very broad 1.1.3 EA resin is formed by the reaction of EP (epoxy resin) and acrylate: firstly, unsaturated group is introduced into EP, then carboxyl group is introduced as hydrophilic group by the reaction of hydroxyl group in EA with anhydrides (such as maleic anhydride, trimellitic anhydride and pyromellitic anhydride), and finally neutralized with alkali (to achieve the effect of water dispersion or water solubility) EA can be initiated either directly by cation or by free radicals when it is combined with compounds containing unsaturated bonds, so it has been widely used as a light curing oligomer The UV curing film with EA as prepolymer has many advantages, such as high gloss, high hardness, good adhesion, chemical stability and heat resistance Guo Songxi prepared UV curable waterborne EA coating for paper, and discussed the influence of coating components and their contents on the properties of cured film Liu et al Synthesized a new type of naphthyl water-based EA resin and characterized its unique thermal stability by TGA Although EA resin has high hardness and rigidity, it still has some disadvantages, such as high viscosity, high brittleness and poor flexibility Zang Limin et al Synthesized UV curable EA with aliphatic EP and acrylate, and then introduced carboxyl group into the molecular chain to synthesize a New Modified Waterborne UV curable EA Xiao et al Prepared a kind of water-based EA / silica sol nanocomposite, and discussed the influence of photoinitiator, curing time and other factors on the curing degree of the coating Bao et al Synthesized hyperbranched waterborne PUA by introducing hydroxyl group into hyperbranched Pu molecular chain and reacting with waterborne acrylate; then the hyperbranched waterborne PUA and EA were mixed in different proportion and cured by UV irradiation to obtain hyperbranched composite UV coating The impact strength of the composite UV coating is twice that of the pure EA UV coating Min Shaojin et al first synthesized waterborne UV curable EA and another EP emulsion, then modified the waterborne UV curing EA with EP emulsion, and obtained a double curing (UV curing and heat curing) emulsion The results show that when the M (waterborne UV curing EA): m (EP emulsion) =4: 1, the hardness and water resistance of the cured film are relatively optimal Chang et al Discussed the influence of curing process on EA UV curing / PU double curing wood coating The results show that the tensile strength, elongation at break, impact strength and light resistance of the cured film are better than those of the traditional UV curing products 1.2 at present, UV curable resin has been widely used in prepolymer of curing system such as paint, ink and adhesive As a new, environmental friendly and energy-saving resin, water-based UV curable resin has better properties than traditional UV curable resin Water borne UV curable coating can be applied to paper varnish, screen printing ink, lithography ink and plastic Varnish, varnish and leather coating can also be used in photopolymer printing plate, gravure printing ink and flexographic printing ink and other application fields (many high-quality printing inks adopt multi-color overprint process, only low solid content of water-based UV curing coating can meet this requirement), and even in woodwork, wood finishing and other aspects also have higher