| EPVC is synthesized by emulsion polymerization, and it has small particlesize and soft texture as Talc compared with PVC resin synthesized by suspensionpolymerization, which applies to such industrial lines as automobile, electronic,electronic toy and so on. Dip-molding originated from German at1952, anddeveloped in Asia. The dip-molding has many advantages included simplicity inprocess, convenience in operation, friendliness in environment and effectiveness inenergy management, which can offset disadvantages of injection-molding includedcomplexity in process and greatness in energy consumption, especially in small sizeproduct and small-lot production.In this paper, DINP and ESO as plasticizers, PVC as base resin, anddip-molding as processing technique were used to compare the differences ofplasticizing process and plasticizing effect between DINP and ESO; the EPVCplastisols with different contents of Ca/Zn stabilizer were prepared to analyse themechanical property and heat stability of products, optimize the recipe of plastisol,and search the optimum content of Ca/Zn stabilizer. The results show that theviscosity stability of EPVC plastisol plastified by DINP is relatively good, and theviscosity of EPVC plastisol plastified by ESO increases with the lengthening ofplacement time, and in this plastisol there are resin particles agglomerates. By theheating effect, the rate of EPVC plastisol plastified by DINP is relative high, andthe over-plasticizing is probably present. However, the rate of EPVC plastisolplastified by ESO is relative low with good stability, and no black holes caused bydegradation have been emerged in plasticizing process, and ESO is better thanDINP in the respect of plasticizer migration; there has been delay in plasticizingprocess with the increase of Ca/Zn stabilizer, and the interfaces between plasticizerunits absorbing EPVC resin particles are clearly visible. The weight loss of EPVCdecreases with the increase of Ca/Zn stabilizer, and percentage of increasing yieldof heat resistance decreases when the addition level of Ca/Zn stabilizer exceeded3phr.The cooling process in dip-molding was simulated by mathematics modelingto derive the formula of cooling time which apply to cooling process of EPVCdip-molding to discuss and analyse its rationality compared with empirical formula. The results show that the shrinkage of products is smaller and the tensile propertyof product in initial stage is better when the derived formula is used. The influenceof cooling time for the tensile property of product in initial stage is weaken with thelengthening of time.The polyurethane prepolymers were prepared by co-polymerization in whichPU and hydroxy silicone oil were linked together by chemical bonds, and acryliccoatings modified with silicone were prepared by co-polymerization betweenpolyurethane prepolymers and acrylate monomer, and then the coating films wereprepared by crosslinking reaction to characterize and analyse their structures andproperties. In addition, the silicone-modified coatings were coated onto EPVC toresearch the coating property and protection function. The results show that theviscosity of synthetic resin rises with the increase of the silicone-containingpolyurethane, and the increase of system viscosity is gradually reduced with theincrease of the molecular weight of hydroxy silicone oil. All kinds of acyliccoatings are similar in degradation. When the content of polyurethane prepolymeris low, the hear resistance of system changes little. When the content ofpolyurethane prepolymer is over15%, the hear resistance has a great improvement.In the way of performances of coatings, the adhesive force between coating andEPVC changes little with the increase of polyurethane prepolymer, and the waterabsorption reduces with the increase of hydroxy silicone oil, and the impactstrength increases at first but decreases finally with the increase of polyurethaneprepolymer. The EPVC is less corrosive to metal after coating, and the oxygenaging resistance increases by a certain extent. |
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