| The water-borne coating is much favored by people because of using water as solvent, non-toxic, energy saving, environmental protection, while the release of VOC content can be significantly lower than the organic solvent coating. Due to its low coSt, faSt drying, gloss, hardness and excellent durability and other characteristics, alkyd resin plays a prominent role in the coatings industry. However the water-borne alkyd coating can’t meet the requirement of market due to its slow drying rate, poor Storage Stability, water resistance and solvent resistance. Developing the good overall performance of the resin film such as water resistance, dry and solvent resistance is our future direction and goals for researchers.In this paper, an epoxy-modified water-borne alkyd resin was prepared by reflux solvent aqueous method. On the basis of the preparation of the epoxy-modified water-borne alkyd resin, further modification with acrylic monomers and acrylic pre-polymer to synthesized epoxy/acrylic monomer-modified water-borne alkyd resin and epoxy/acrylic pre-polymer modified water-borne alkyd resin respectively. The different variables and technological conditions that affect the performances of the resin were discussed, the Structure and properties of the resin was characterized. At last, the best synthetic conditions and experiment scheme of the water-borne alkyd resin was obtained. The product’s Structure, particle size distribution, thermal Stability and glass State temperature were analyzed by FT-IR, TEM, TGA and DSC. Malvern particle size analyzer and transmission electron microscope was used to test the particle size and its distribution. The main contents were as follows:Epoxy-modified alkyd amino-baking coatings:an epoxy-modified water-borne alkyd resin was prepared within Soybean oil fatty acid as fatty acid, the epoxy resin as a modifier. The suitable alcohol surplus was 1.10～1.15, the amount of epoxy resin E-44 was 10.6%～15.2%(based on mass of the total monomer), terminal acid value 30-40mg KOH/g. The properties of the water-borne epoxy-modified alkyd resin were as followed:the adhesive power achieved the first level, hardness was 4H, impact resistance was 50kg·cm, the ethanol scrub resistance was 32 times, the xylene scrub resistance was 13 times. The amount of double bond in molecular chain of the resin is low and the drying rate of coating film is slow, so it can be used to prepare the paint.Epoxy-modified alkyd amino-baking coatings:An epoxy-modified water-borne alkyd resin was prepared within Soybean oil fatty acid as fatty acid, the epoxy resin as a modifier. The suitable alcohol surplus was 1.10～1.15, the amount of epoxy resin E-44 was 10.6%～15.2%(based on mass of the total monomer), terminal acid value 30～40mg KOH/g. The properties of the water-borne epoxy-modified alkyd resin were as followed:the adhesive power achieved the first level, hardness was 4H, impact resistance was 50kg·cm, the ethanol scrub resistance was 32 times, the xylene scrub resistance was 13 times. The amount of double bond in molecular chain of the resin is low and the drying rate of coating film is slow, so it can be used to prepare the paint. Two-component alkyd amino paint was prepared with epoxy-modified water-borne alkyd resin as component A, high methylated melamine-formaldehyde resin as component B. When the mass ratio of alkyd resin and amino resins is 2:1, their coating properties were excellent.Epoxy/acrylic monomer-modified alkyd resin:On the basis of the preparation of the epoxy-modified alkyd resin, epoxy/acrylic monomer-modified alkyd resin was prepared with linolenic acid as fatty acid, the epoxy resin, acrylic acid, methyl methacrylate, butyl acrylate, Styrene as modifiers. The results showed that the beSt conditions of epoxy/acrylic monomer-modified alkyd resin were as followed:the amount of epoxy resin E-44 was 9～14%, the amount of acrylic acid was 7%, the terminal acid value was 40～50mg KOH/g, the degree of neutralization was 80%. In this condition, modified alkyd resin was analyzed successfully with uniform partical size distribution, excellent water solubility and water resistance, hardness was 4H, the adhesive power achieved the first level impact resistance was 50 kg-cm, the ethanol scrub resistance was 28 times, the xylene scrub resistance was 12 times. The amount of double bond in molecular chain of the resin is high and the emulsion dried fast, so it can be used to prepare the varnish with water dispersible driers.Epoxy/acrylic pre-polymer modified alkyd resin:At first, a new modified acrylic pre-polymer was synthesized by the copolymerization of aleic anhydride, butyl methacrylate, butyl acrylate, Styrene. Then epoxy/acrylic pre-polymer modified water-borne alkyd resin was prepared by the copolycondensation of acrylic pre-polymer, linoleic acid, trimethylol propane, phthalic anhydride in which acrylic pre-polymer as dibasic acid. The results show that when the amount of acrylic pre- polymer was 5%-8%, the terminal acid value was 60-70mg KOH/g. In this condition, surface drying time, hard drying time, the hardness, impact resistance and adhesion of the resin were 3h,16h,2H,50kg·cm, and 1 level. The water resistance keep constant for 48h, the ethanol scrub resistance was 32 times, the xylene scrub resistance was 14 times. The amount of double bond in molecular chain is high and it can be air dried, so it can be used to prepare the primer with water drying agent, pigment and co-solvent. |
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