Synthesis and characterization of acrylic-grafted polyester coatings for automotive pre-coated metal

An automotive pre-coated metal (PCM) system has been investigated to remove the wet coating process, such as pre-treatment, dip coating and spray coating for environmental regulations. However, automotive pre-coated metal sheets must have high flexibility and stiffness to overcome the harsh conditions such as encountered in cutting, press and the stamping process. For these reasons, a series of acrylic-grafted polyester coatings (i.e., AGP-0, AGP-10, AGP-20, AGP-30) were designed to satisfy both the surface hardness and the formability for an automotive PCM. The characteristics of the resins were measured by GPC, FT-IR and ¹H NMR. The viscoelastic behavior and flexibility was evaluated using DMA and UTM. The physical properties such as pendulum hardness, pencil hardness and adhesion were measured to define the effect of incorporating acrylates. A cylindrical deep drawing tester was used to evaluate the formability of coatings.     

Synthesis and characterization of elastomeric polyester coatings for automotive pre-coated metal

An automotive pre-coated metal system (PCM) has been investigated to replace wet coating process, such as pre-treatment, dip coating and spray coating, to address environmental regulations. However, automotive pre-coated metal sheets must have high flexibility and stiffness to overcome harsh conditions such as cutting, press and stamping processes. For these reasons, elastomeric polyester coatings were designed to improve scratch resistance and to impart reflow characteristic for an automotive PCM. The characteristics, curing behavior and viscoelastic property of the resins were measured by ¹H NMR, GPC, RPT and DMA. The flexibility was evaluated using a texture analyzer. A nano scratch tester, equipped with an optical microscope was used to measure the scratch resistance of coatings and the scratched surface morphology. An Amtec laboratory car wash test and a sharp knife were used to evaluate the reflow property of the coatings. Change of the damaged surface morphology was measured using a mini-SEM.     

Synthesis and characterization of flexible polyester coatings for automotive pre-coated metal

An automotive pre-coated metal system has investigated to remove the wet coating process, such as pre-treatment, dip coating and spray coating for environmental regulations. However, automotive pre-coated metal sheets must have high flexibility and formability to overcome the harsh conditions such as cutting, press and stamping process. For these reasons, flexible polyester coatings were designed to control flexibility using polycarbonatediol. The characteristics, curing behavior and viscoelastic property of the resins were measured by FT-IR, GPC, rheometer, DSC, RPT and DMA. The flexibility was evaluated using a texture analyzer. A nano-scratch tester, equipped optical microscope can measure the scratch resistance of coatings and the scratched surface morphology.With increasing polycarbonatediol content, the final frequency and the storage modulus increased and the T_g of the coatings decreased. This is related to the high mobility of the chain segment in polycarbonatediol. In terms of the flexibility and scratch resistance, CP-3 had high elongation value and good scratch resistance resulting from optimized stamping, pressing and cutting process in automotive pre-coated metal system. Therefore, polycarbonatediol is a powerful factor affecting the flexibility and scratch resistance of polyester coatings.     

Outstanding cavitation erosion resistance of hydrophobic polydimethylsiloxane-based polyurethane coatings

Cavitation erosion will create shock waves and water jets in turbulent flows. These impact pressures will affect the surface, which will lead to crack propagation and severe material degradation. In this study, we have developed hydrophobic polydimethylsiloxane-based polyurethanes (Si-PUx) with hydroxypropyl polydimethylsiloxane (H-PDMS) and polytetramethylene glycol (PTMG) as mixed soft segments and 2,4-tolylene diisocyanate, 1,4-butanediol, triethanolamine as hard segments via a polycondensation reaction and studied its properties. The cavitation wear experiment showed that the cavitation erosion resistance of Si-PUx coating continuously improved with the increase of H-PDMS content, while the adhesion force of Si-PUs reduced with the increasing of H-PDMS content. The surface of Si-PUx coating after cavitation test was observed using an optical microscope and three-dimensional profiler. The cumulative mass loss of Si-PUx with 12.5 wt % H-PDMS was only 2.96 mg and the surface showed no obvious holes and cracks after 80 h cavitation. The results showed that cavitation resistance had a correlation with degree of water resistance, hardness, adhesion strength, and dynamic mechanical properties of coating. It seemed that the Si-PUx coating could withstand a longer period cavitation erosion resistance compared to high strength epoxy, which could be used as protective coating for flow components under water. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47668.     

Rheology and roll coating dynamics of metallic basecoats for automotive pre-coated metal sheet

Rheological behavior and coating dynamics of solvent-based metallic basecoats using 3-roll coaters were investigated for the application process based on pre-coated metal (PCM) sheet technology that can promisingly diminish the environmental pollutants in automotive OEM line. Rheological properties of the metallic basecoats related to optical appearance and color variations were measured by altering the content of aluminum (Al) flake and temperature of the coating solution. The results showed that the basecoats exhibited a very weak shear-thinning behavior regardless of Al flake contents in this study. However, their elastic behaviors were intensified with increasing the Al flake content. From the 3-roll coating experiments with forward and reverse coating modes, the operability windows in the coating process, demarcating the uniform coating flow from defects, were established. In particular, it was possible to elucidate the relationship between the capillary number and speed ratio conditions for the desired coating thickness in roll coating systems accompanied with reverse coating mode between the pick-up and metering rolls. It was verified from the cross-sectional images of coating layers that most of Al flakes inside the basecoat layer were oriented parallel to the coating surface under the continuous roll coating flows.     

Synthesis and characterization of new modified anti-corrosive polyesteramide resins incorporated pyromellitimide ring for surface coating

In this paper new modified anti-corrosive polyesteramide resins were obtained by means of a condensation polymerization reaction between N,N-bis (2-hydroxyethyl) linseed oil fatty acid amide (HELA) and phthalic anhydride (PA), which was partially replaced with pyromellitimide acetic acid (PAA) as a new dibasic acid source. The structure of the resin was confirmed by FT-IR and ¹H NMR spectral studies. The coatings of 50 ± 5 μm thickness were applied to the surface of glass panels and mild steel strips by means of a brush. The coating performance of the resins was evaluated using international standard test methods and involved the measurement of phyisco-mechanical properties such as viscosity, drying time, specular gloss, pencil hardness, adhesion, flexibility and impact resistance. Chemical resistance of the resins to water, acid, alkali and solvent was also evaluated to ascertain their suitability as a surface coatings vehicle. The results show that the modification enhances both phyisco-mechanical and chemical properties. The resins were incorporated within primer formulations and evaluated as anti-corrosive single coatings. The results illustrate that the introduction of pyromellitimide acetic acid, containing a pyromellitimide ring, within the resin structure, enhances the corrosion resistance performance of polyesteramide resins.     

Synthesis and characterization of silicone-modified polyester as a clearcoat for automotive pre-coated metals

Four types of silicone-modified polyester resins were synthesized for cleanable characteristics with silicone intermediate, which has a long chain, to extend the polymer chains of the resins. These resins were formulated to make polyester/melamine heat-cured coatings to control the formability. The characteristics, viscoelastic behavior and flexibility of the resins were measured by DMA and tensile test. The contact angle measurement can be measured by the water repellence of the coating surface, which is a standard method to evaluate cleanable characteristics. The surface free energy was calculated by the contact angle measurement, and the surface analysis of each cured coating was evaluated using an XPS. Silicone-modified polyester coatings were coated on the cold rolled steel sheets to verify their formability, using a deep drawing test. Results showed that the storage modulus decreased, and the glass transition temperature shifted to a lower temperature with increasing contents of silicone intermediate. So, silicone intermediate provides lower stiffness and higher softness to polyester coating. To analyze the formability, we calculated F_U (the forming coefficient based on strain energy) and F_? (the forming coefficient based on strain). When F_U and F_? are both larger than 1, the polyester coatings have good formability. CSiPE-3 and CSiPE-5 had good formability. Also, CSiPE-5, which had the highest amount of silicone intermediate, had 93.5° of water contact angle, and had 26.5 mN/m of surface free energy and had 5.5 N/25 mm of the peel strength. So, it is implied that silicone intermediate can give a low surface energy and peel strength to polyester coatings. From those tests, the polyester/melamine coating of CSiPE-5 that had 0.5 mol of silicone intermediate had good formability and low peel strength, which are semi-removable characteristics. So, it would be an appropriate coating as a clearcoat for automotive pre-coated metals.     

家电板用黑色导电背漆的研制

讨论了家电板用黑色导电背漆的研制,着重讨论了导电材料的选用、树脂、颜填料及助剂对涂膜导电性能的影响。     

线性低聚物为致孔剂制备苯乙烯-二乙烯苯大孔共聚物

利用线型低聚物聚丙二醇(PPG)和正庚烷为混合致孔剂,采用悬浮聚合法合成了一系列聚苯乙烯-二乙烯苯灌注色谱分离介质,采用扫描电镜和压汞仪对介质的孔形貌和孔结构进行了表征。考察了交联度、致孔剂聚丙二醇和正庚烷的质量比、聚丙二醇相对分子质量和致孔剂与单体质量比等因素对介质孔结构和孔形貌的影响。研究结果表明,当聚丙二醇与正庚烷以一定比例混合作致孔剂时,可得到一类孔径大于1 000 nm的聚苯乙烯-二乙烯苯型灌注色谱分离介质。该研究为灌注型色谱分离介质提供了一种新的制备方法。     

Effect of the NCO/OH ratio on the properties of Mesua Ferrea L. seed oil‐modified polyurethane resins

A series of polyurethane resins with varying NCO/OH ratios (0.8–2.0) has been synthesized from the monoglyceride of Mesua Ferrea L. seed oil, poly(ethylene glycol) (M_n, 200 g mol^?1) and 2,4‐toluene diisocyanate in the presence of dibutyl tin dilaurate as the catalyst. The effects of the NCO/OH ratios of the synthesized resins on the physical properties, such as hydroxy values, acid values, saponification values, iodine values, specific gravities and isocyanate values have been studied. The formation of the polyurethane resins was confirmed by viscosity measurements, and FTIR, UV and ¹H NMR spectroscopic studies. Performance characteristics, such as impact resistance, flexibility, gloss, hardness, adhesive strength and chemical resistance, of the cured resins were investigated as a function of the varying NCO/OH ratios, with an influence of these ratios being observed for most of the above properties. Thermogravimetric analysis (TGA) demonstrated that the thermal stabilities of the cured resins increased with an increase in the NCO/OH ratios. The amounts of char residues at 550 °C were also found to be greater for higher NCO/OH ratios of the oil‐modified polyurethane resins. Copyright © 2005 Society of Chemical Industry     

Curable resins based on recycled poly(ethylene terephthalate) for coating applications

Poly(ethylene terephthalate) waste was depolymerised in the presence of diethylene- or tetraethylene glycol and manganese acetate as a catalyst. An epoxy resin was then prepared by the reaction of these oligomers with epichlorohydrin in presence of NaOH as a catalyst. The produced oligomers were condensed with maleic anhydride and ethylene glycol to produce unsaturated polyester. The chemical structures of the resulting epoxy and unsaturated polyester resins were confirmed by ¹HNMR. The vinyl ester resins were used as cross-linking agents for unsaturated polyester resin diluted with styrene, using free radical initiator and accelerator. The 2-amino ethyl piprazine was used as hardener for epoxy resins. The curing behaviour of the unsaturated polyester resin, vinyl ester resins and styrene was evaluated at different temperatures ranged from 25 to 55 °C to calculate the curing activation energy of the system. The cured epoxy and unsaturated polyester resins were evaluated in coating application of steel.     

Poly(polyethylene glycol methyl ether methacrylate) as novel solid-solid phase change material for thermal energy storage

Poly(polyethylene glycol methyl ether methacrylate) as novel solid–solid phase change materials (PCMs) for thermal energy storage was prepared via the facile bulk polymerization of polyethylene glycol methyl ether methacrylate and was characterized by Fourier transform infrared, ¹³C-NMR, X-ray diffraction, differential scanning calorimetry, and thermogravimetric analysis measurements. Based on the results, it is indicated that the poly (polyethylene glycol methyl ether methacrylate) as novel PCM showed solid–solid properties with suitable transition temperature, high transition enthalpy, and good thermal stability, which was apt to crystallize due to the flexibility of long polyether side chain. This novel PCMs have advantages for the potential application in energy storage. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

汽车用聚丙烯树脂的开发及国内应用现状

介绍了汽车用聚丙烯（PP）基础树脂的开发现状,简述了国内汽车用改性PP材料的应用概况,并展望了其未来的发展趋势。高模量、高抗冲、高流动PP是汽车用PP的主要品种,汽车用改性PP主要包括无机填料和弹性体增强增韧改性PP、玻璃纤维改性PP、低气味改性PP、耐刮擦PP等;汽车用改性PP的回收利用也变得越来越重要。     

桐油改性双环戊二烯不饱和树脂的合成及其性能研究

采用催化水解加成法合成了桐油改性双环戊二烯不饱和聚酯,通过对桐油滴加前后不饱和聚酯的凝胶色谱及红外表征,证实了桐油与不饱和聚酯分子链中的双键发生了Diels-Alder反应。研究了桐油加入量对树脂涂膜的气干性、附着力、柔韧性、硬度、耐磨性及树脂耐热性能的影响,并确定了桐油的最佳加入量。结果表明:较未改性的双环戊二烯不饱和聚酯(DCPD-UPR),桐油基DCPD-UPR的涂膜具有更好的气干性、柔韧性、粘接性和耐磨性,并且桐油基DCPD-UPR的耐热性也优于未改性的DCPD-UPR。     

含有疏水化剂的水性环氧树脂的制备与性能

以聚丙二醇（PPG）和双酚A型环氧树脂为原料,使用特殊催化剂合成了水性环氧树脂涂料用疏水性剂基体,并在其中添加疏水性微粒子WS-12组成疏水化剂。使用该疏水化剂与水性环氧树脂、通用环氧树脂按一定比例混合调制成水性环氧涂料复合物,并研究和评价其固化物的力学性能及涂膜的相关性能。研究结果表明,当m（水性环氧树脂）：m（疏水化剂）：m（环氧树脂6002）=20：10：70时,树脂固化物及涂膜的力学与物理性能最佳。     

Preparation and characterization of Jatropha Curcas oil based alkyd resin suitable for surface coating

Jatropha Curcas oil was extracted from Jatropha seeds by solvent extraction method. Three different alkyd resins have been developed from Jatropha Curcas oil by varying the amount of phthalic and maleic anhydride. The prepared resins are cured by using methyl-ethyl ketone peroxide (MEKP) as initiator and Co-octoate as an accelerator at 120 °C. The characterizations of the resins for structure establishment is carried out using Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (¹H NMR) spectroscopic techniques. The concomitant properties of the cured resins such as acid value, saponification value, viscosity, molecular weight, etc. are also evaluated by standard methods. The cured resins have been tested for chemical resistance, pencil hardness, adhesion, thermal stability and gloss and it can be concluded that the resins may find potential applications in surface coating purposes.     

Mesua ferrea L. seed oil‐based epoxy resins

Exhaustion of fossil fuels, tremendous increase of materials demand, and unpredictable prices of petroleum based products urge upon the sustainable development. Three different epoxy resins have been synthesized from monoglyceride of Mesua ferrea L. seed oil and epichlorohydrin with and without other dihydroxy compound like tetrabromobisphenol‐A (TBPA) and bisphenol‐A (BPA). The synthesized epoxy resin were characterized by measurement of physical properties like epoxy equivalent, viscosity, hydroxyl value, saponification value, acid value, etc., and spectroscopic techniques like FTIR and ¹H NMR. High thermostability with initial decompositions temperature of 225–265°C was observed for the cured resins and 75 mol % BPA based resin exhibits the highest thermostability. Newtonian flow behavior was observed for all resins as indicated by the rheometric study (CVO 100). The flame retardency rating of TBPA based epoxy was found to be V1 as tested by UL 94. The performance characteristics as coating materials were studied by the measurement of gloss, impact resistance, scratch hardness, tensile strength, elongation at break, adhesive strength, and chemical resistance. The results indicate the suitability of the synthesized resins as coating materials. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis of unsaturated polyester resins based on rosin acrylic acid adduct for coating applications

Unsaturated polyester, UP, resins were obtained by reacting the propylene or ethylene glycol, PG or EG, with different acrylopimaric adducts APA, maleic anhydride as a source of double bond, phthalic anhydride and adibic acid as dibasic acids. The molecular weights of UP were determined by end group analysis. The chemical structures of the resulting UP resins were confirmed by ¹H NMR analysis. The curing exotherm of UP, vinyl ester resins (VE) and styrene was evaluated at temperatures from 35 to 55 °C using free radical initiator and accelerator. The curing behaviors of cured UP resins with styrene were evaluated by DSC measurements. The prepared UP curable resins were evaluated in the field of steel coating by measuring their mechanical properties and chemical resistance.     

Waterborne polysiloxane–urethane–urea for potential marine coatings

Waterborne polysiloxane–urethane–ureas (WBPSUU) were prepared through a prepolymer process using siloxane polyol, namely polydimethylsiloxane (PDMS) and polyether polyol, namely poly(tetramethyleneoxide glycol) (PTMG) as the soft segments. The goal of this study was to explore the potential use of polysiloxane–urethane–urea in marine coatings in order to boost the flexibility, adhesion, erosion, and foul-release property with respect to PDMS/PTMG ratio (PDMS wt%). The structural elucidation of the synthesized waterborne polyurethane and WBPSUU was carried out by FTIR, ¹H NMR, and ²⁹Si NMR spectroscopic techniques. The XPS and AFM analyses indicate that the polymer surface can be silicone enriched with the optimum PDMS content (15.76 wt%). The antifouling property of the coatings was investigated by the immersion test under a marine environment for 90 days. The fouled area was calculated for all the samples and the fouled area (%) decreased with increasing PDMS content. After 90 days the lowest fouled area (5%) was observed in the sample using WBPSUU4 (PDMS 15.76 wt%) among all of the samples.     

Brillouin scattering from oligomers of polydimethylsiloxane and the assignment of the hypersonic a loss peak in polymers

Hypersonic sound speed and loss have been measured in poly(dimethylsiloxane) fluids of viscosities 0.65 to 3.5 × 10⁴ centistoke. Both rise to a plateau level for viscosity values in excess of ～10 centistokes. Loss measurements as a function of temperature indicate that the α loss temperature (T_α) in the dimer is depressed below 180K compared to 230K in the high molecular weight materials. This molecular weight dependence of T_α is used to account for the hypersonic loss as a function of molecular weight in polystyrene and polypropylene glycol in addition to the assignment of the α loss peak in polydimethylsiloxane.