The Preparation And Properties Of Novel Automotive Chip-resistant Coat Based On The PVC

PVC coating is the main type product in the auto-underbody coating market. All of its performance is satisfying relatively. It has excellent strength, chip-resistant performance, corrosion-resistant performance at the cheapest cost. However, with the developing of the automotive industry and production technology, PVC stone-chip resistance of automotive coatings have some problems in use, such as adaptability of coating with electrophoresis plate, sagging and slipping. To solve the problem, this essay tries to modify the PVC coating with silane coupling agent IPN method, then characterized it. This work addresses the influence of silane coupling agent to these performances, including the sagging and slipping resistance, the mechanical property, the adhesive property, the rheology behavior, the abrasion resistance. We also deeply analyze the mechanisms and propose a new method for PVC coating modification.In this paper, PVC stone-chip resistance of automotive coatings are modified by IPN method with double amino-group silane coupling agent Z-6020 and vinyl-group silane coupling agent polymer poly-A-172. It is shown that the sagging & slipping resistance and the mechanical property can be enhanced with the increase of the amount of silane coupling agent. The results indicated that under the optimal dosage of silane coupling agent, the slipping length decreases from 70 mm to 0, and the sagging length decreases from 19 mm to 1 mm. The tensile strength increase from 1.13 MPa to 3.16 MPa, with growth of 179.6%, and the elongation also slightly increases. The IPN system improves the bond performance obviously, and the shear strength increase from 0.77 MPa to 2.04 MPa, with growth of 164.9%. The IPN modify with silane coupling agent is also useful in improving the rheology behavior and the abrasion resistance.The PVC coating, modified by IPN method with silane coupling agent is characterized by contact angle meter, FTIR, DSC, SEM. The results show that the modified PVC coating has better wettability to electrophoresis plate. The hydrogen bond and chemical bond are formed between PVC coating and electrocoat. Besides, the IPN structures among the system are beneficial to enhance the cohesion. So the above performances increase.