Synthesis and properties of cationic resins derived from aniline/benzylamine-modified epoxy resins and diethylamines

Aniline/benzylamine-modified epoxy resins with different molecular weights, which contain tertiary amines in the middle of the polymer chain, were synthesized by the reaction of aniline/benzylamine with epoxy resin at various molar ratios. The resulting aniline/benzylamine-modified epoxy resins were reacted with diethylamine and subsequently reacted with 2-ethylhexanol-blocked toluene diisocyanate to obtain thermally crosslinkable resins which contain tertiary amines at the end and in the middle of the polymer chain. These resins were partially neutralixed with acetic acid to give thermally crosslinkable cationic resins. The resulting cationic resins were dissolved in suitable solvents and mixed with deionized water to form various emulsions. The emulsion and electrodeposition properties of these resins were studied in some detail to compare the properties of these cationic resins. The results show that the deposition yields and throwing power of the emulsions prepared from benzylaminemodified epoxy resins are higher than those of the emulsions prepared from anilinemodified epoxy resins. The emulsion having proper pH values can give a high throwing power. High throwing power is the characteristic property of these modified cationic resins. Factors determining the throwing power and deposition yield of the emulsions were also investigated.     

Synthesis and properties of cationic resins derived from aniline-modified epoxy resins and various amines

Aniline-modified epoxy resin which contains tertiary amine in the middle of the polymer chain was synthesized by the reaction of aniline and epoxy resin. The resulting aniline-modified epoxy resin and two commercial epoxy resins with different epoxy equivalent weights were reacted with 2-ethylhexanol-blocked toluene diisocyanate (2-EH-blocked TDI) to obtain thermally crosslinkable epoxy resins. These epoxy resins were subsequently reacted with various secondary amines and partially neutralized with acetic acid to give thermally crosslinkable cationic resins. The resulting cationic resins were dissolved in suitable solvents and mixed with deionized water to form emulsions. The crosslinking properties, emulsion, and electrodeposition properties of these resins were studied in some detail. The electro-deposition yields of the emulsions prepared from aniline-modified epoxy resins were higher than those of other emulsions. The crosslinked films prepared from aniline-modified epoxy resins were also glossier than those prepared from commercial epoxy resins. High deposition yield and high glossiness were the characteristic properties of the aniline-modified epoxy resins. Thermal properties were not affected by aniline-modified epoxy resins.     

New polymeric polyol for thermoset coatings: Superacid-catalyzed copolymerization of water and epoxy resins

Though free-radical emulsion polymerization has been studied extensively, published reports of cationic (i.e., acid-catalyzed) polymerizations of emulsified monomers are rare. It was recently discovered that treatment of an emulsion of liquid epoxy resin with select superacid catalysts yields a polymeric polyol. Catalysis with one percent perchloric acid at room temperature yields a product with a number average molecular weight of 1650, and a polydispersity of 5.0 as measured by GPC. The polyol’s structure differs from that of conventional high molecular weight epoxy resins prepared by the advancement process in several ways, including the incorporation of two glycidyl units in the repeat unit. In essence, the product is a copolymer of the epoxy resin and water, in which water is incorporated in the repeat unit structure by reaction with two epoxide groups. A similar product can be prepared by solution polymerization, where the molecular weight is controlled by the ratio of water to epoxy resin. The product was shown to have lower levels of residual bisphenol-A diglycidyl ether (BADGE) and bisphenol-A than conventional advanced epoxy resins. Polyols prepared by these new processes were crosslinked with melamine-formaldehyde resins in waterborne coating formulations which were free of added cosolvent, as well as solventborne coating formulations. The coatings developed excellent solvent resistance at lower bake temperatures than traditional epoxy resins. Presented at the 79th FSCT Annual Meeting in Atlanta, GA, Nov. 5–7, 2001. 7201 Hamilton Blvd., Allentown, PA 18195-1501.     

Syntheses and properties of cationic amine–epoxy adducts and their use in electrodeposition: I. Diethanolamine/diethylamine terminated cationic epoxy with pendant 2-ethylhexanol-blocked TDI groups

Alkyl partially blocked toluene diisocyanate (PBTDI) and hydroxyl group-containing polyepoxide were mixed to produce a blocked TDI–epoxy resin and then reacted with secondary amine and treated with acetic acid to give a cationic resin. In this study, six cationic resins (IV-A and IV-B, two series) were synthesized from three diglycidyl ethers of bisphenol A with different epoxy equivalent weights of 508, 650, and 950, and two secondary amines (diethylamine and diethanolamine). Acetic acid was used as the neutralization agent and ethylene glycol mono-n-butyl ether (butyl cellosolve, BCS) and deionized water were utilized as the emulsion solvents. Some properties of electrodeposition, such as throwing power and rupture voltage, and some physical and chemical properties of the deposited films were investigated. It was found that the appearance of emulsion, deposition yields, and quality of the deposited films are strongly dependent on pH, BCS, and resin contents. To obtain suitable deposition properties and stable emulsions from IV-A and IV-B systems, the aqueous dispersion should meet the following conditions: pH, 5.5-6.0; BCS contents, 3.0–5.0 wt %; and resin concentration, 7.0–9.0 wt %. For both systems, the deposited films had good appearance, adhesion, hardness, and alkali reagent resistance. The salt spray resistance and acid resistance of films deposited from series III-A (epoxy resin formulations containing diethylamine) are superior to films deposited from series III-B (epoxy resin formulations containing diethanolamine).     

Polyether and polyester polyol based glycidyl-terminated polyurethane modified epoxy resins: Mechanical properties and morphology

A glycidyl-terminated polyurethane prepolymer was synthesized and used to enhance the properties of epoxy resins. Some properties of glycidyl-terminated PU/epoxy with polyether based (PPG) and polyester based (PBA) glycidyl-terminated PU were investigated in this research. The polyether based glycidyl-terminated PU(PPG) modified epoxy resin proved to be superior to conventional epoxy resins in improved impact strength and fracture energy, but not tensile strength, tensile modulus, flexural strength and flexural modulus. On the other hand, the polyester based glycidyl-terminated PU(PBA) modified epoxy resin had increased mechanical properties while showing slight variation of impact strength and fracture energy. Different mechanisms for this behaviour are advanced in this paper.     

Synthesis and properties of cationic amine-epoxy adducts and their use in electrodeposition,II. Diethanolamine/diketimine terminated cationic epoxy resins with pendent 2-ethylhexanol-blocked TDI groups

A diglycidylether of bisphenol A epoxy resin (DGEBA) was first reacted with 2,4-toluene diisocyanate partially blocked with 2-ethylhexanol (2-EH P. B. TDI) to form modified epoxy resins, and subsequently reacted with different molar ratios of diethanolamine and bis(2-methylisobutylketiminoethyl)amine (DKI) (used as ring opening agents) to give diethanolamine/diketimine terminated resins. These resins were hydrolyzed and neutralized with acetic acid to give cationic resins containing various contents of primary amine groups in the terminal polymeric chain. These cationic resins can be dissolved in a suitable solvent and mixed with deionized water to obtain emulsions. The electrodeposition properties and characteristics of the resulting cationic resins were investigated in detail. The effects of hydrophobic solvents, such as hexyl cellosolve (HCS) and toluene, on the deposition properties of the emulsions are discussed.     

聚醚胺固化环氧树脂胶粘剂的研究

以聚醚胺D-230为固化剂,研究了多官能度环氧树脂和硫酸钙晶须的加入对环氧树脂胶粘剂粘接性能的影响。研究结果表明,多官能度环氧树脂和改性硫酸钙晶须的加入,很好地改善了环氧树脂胶粘剂的高温性能;当环氧树脂m(E-51)∶m(F-51)∶m(AG-80)=3∶3∶2、改性硫酸钙晶须为树脂总质量的10%时,体系的粘接性能最佳,室温和100℃剪切强度分别为25.91MPa和6.11MPa,室温剥离强度可达5.26kN/m。     

聚乙二醇改性环氧丙烯酸阴极电泳涂料用乳液的制备

以聚醚多元醇改性环氧丙烯酸酯为主体树脂制备了阴极电泳涂料用乳液。讨论了聚醚多元醇的种类和用量对改性环氧丙烯酸乳液及其涂膜性能的影响,以及扩链反应温度和时间对环氧基转化率的影响。通过红外光谱(FT-IR)和热重分析(TG)对改性前后的环氧丙烯酸阳离子树脂进行了表征。试验发现,以PEG1000为扩链剂,用量为13%~14%,在90°C下反应4h,制得的改性环氧丙烯酸乳液平均粒径65.49nm,ζ电位58.3mV,乳液黏度0.21Pa.s,常温下放置300d未分层。改性后的阴极电泳涂料漆膜柔韧性为0.5mm,附着力0级,硬度2H,冲击强度50kg.cm,耐水性达到208h,性能明显优于改性前的漆膜。     

Preparation and electrodeposition properties of trimethylolpropane–toluene diisocyanate–dimethylaminoethanol/2-ethylhexanol resins

2,4-Toluene diisocyanate (TDI) was partially blocked with equimolar mixtures of dimethylaminoethanol (DMAE) and 2-ethylhexanol (2EH) of different ratios to form the DMAE/2EH half-blocked TDIs, which were subsequently reacted with 1/3 mol trimethylolpropane (TMP) to yield the trimethylolpropane–toluene diisocyanate–dimethylaminoethanol/2-ethylhexanol (TMP–TDI–DMAE/2EH) resins having various content of tertiary amine groups. These resins were neutralized with acetic acid and then dispersed in deionized water, resulting in the milky emulsions used for cationic electrodeposition. Some electrodeposition properties, such as deposition yield, conductivity, rupture voltage, and throwing power, of the resins were investigated. In addition, one of the obtained resins (added as a crosslinker) and an amine–epoxy adduct were codispersed in deionized water, and the nature of electrodeposition of the two-component emulsion is discussed.     

Preparation and properties of halogen-free flame retardant epoxy resins with phosphorus-containing siloxanes

Novel epoxy resin modifiers, DOPO–TMDS and DOPO–DMDP were synthesized by addition reaction of divinylsiloxane with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO). Halogen-free flame retardant epoxy resins were obtained through modification of o-cresol novolac epoxy resin cured by phenol novolac resin using DOPO–TMDS and DOPO–DMDP which were characterized by ¹H NMR, ¹³C NMR, ³¹P NMR and FT-IR measurements. Effects of the phosphorus-containing siloxanes on thermal stabilities, mechanical properties and flame retardant properties of the epoxy resins were investigated. The cured epoxy resins exhibited better mechanical properties and greatly improved flame retardant properties due to the presence of phosphorus-containing siloxanes. The cured epoxy resins with phosphorus loading of 2.0 wt% showed LOI values of 32–33 and achieved UL94V-0 ratings.     

重防腐涂料用水性环氧乳液的制备

采用固体双酚A型环氧树脂与高分子量聚醚反应合成水性环氧树脂专用非离子型乳化剂,然后结合相反转技术制备水性环氧乳液。讨论了催化剂三氟化硼乙醚(BF3-乙醚)的用量对环氧树脂CYD011和聚乙二醇PEG6000反应体系环氧值的影响,并利用红外光谱和凝胶渗透色谱对合成乳化剂的结构进行表征,探讨了环氧树脂与PEG6000的摩尔比、乳化剂质量分数、乳化温度及不同分子量的环氧树脂对乳液性能的影响。结果表明,当环氧树脂的环氧当量为450～500,乳化温度为75℃、催化剂用量为0.40%、n(环氧树脂)∶n(PEG6000)=1∶1、乳化剂质量分数为15%时,所制得的水性环氧乳液粒径小于1μm,稳定性高。由此乳液制备的涂料涂膜柔韧性为1mm,冲击强度为50kg·cm,浸泡在质量分数为5%的NaCl溶液中17d完好,耐盐雾480h完好。该乳液可应用于重防腐涂料。     

高性能环氧树脂基体的发展

综述了高性能环氧树脂的制备方法和性能。介绍了几种高性能的环氧树脂固化体系 ,新型的耐湿热性的环氧树脂 ,氰酸酯改性环氧树脂 ,液晶环氧树脂 ,双马来酰亚胺改性环氧树脂等     

水性环氧乳液的研制

采用低相对分子质量环氧树脂、双酚A与聚醚反应，合成了自乳化环氧树脂，再结合相反转技术，制备水性环氧乳液。讨论了聚醚相对分子质量及其用量，环氧树脂与聚醚和双酚A的加料比，以及加料工艺对乳液的粒径和稳定性的影响。     

UV固化水性聚氨酯丙烯酸酯的合成与性能

以异佛尔酮二异氰酸酯(IPDI)、聚醚二元醇(DL-1000)、二羟甲基丙酸(DMPA)和甲基丙烯酸羟乙酯(HEMA)为主要原料合成了具有感光性能的水性聚氨酯丙烯酸酯(PUA)乳液,通过红外光谱对其结构进行了表征。其与活性稀释剂二缩三丙二醇二丙烯酸酯(TPGDA)、光引发剂混合均匀得到水性紫外光(UV)固化树脂。通过涂膜性能测试,研究了各配方组分、UV固化条件等对涂膜性能的影响。结果表明:适宜的DMPA质量分数为5.5%～6.0%,NCO/OH物质的量比为1.55∶1,TPGDA质量分数为10%,光引发剂为TPO,其用量为总树脂质量的4%,光照时间为7.0 s,以其制得的PUA树脂外观、贮存稳定性和耐黄变性良好,涂膜的综合性能最佳。     

亲水性聚醚嵌段环氧树脂的合成及其工艺研究

采用PEG2000与环氧树脂E51以物质的量比为1:2制备了嵌段亲水性聚醚型环氧树脂,通过凝胶色谱和粘度测试研究了催化剂的添加量、催化剂的滴加速率对体系粘度的影响及分子质量分布与体系粘度的关系。结果表明,当体系粘度在800～1600mPa·s时,产物产率达90%以上。     

ELECTRODEPOSITION COATING OF EPOXY RESIN ON PHOSPHATED STEEL: OPTIMIZATION OF KEY FACTORS

Organic coating using electrodeposition method has attracted substantial attention in the last few years. This method of coating provides many advantages, including surface smoothness, less environmental pollution, and good performance of protection against corrosion. In the current investigation, an electrodeposition method was used to coat a uniform layer of epoxy resin on phosphated stainless steel plate. Epoxy resin was converted to cationic tertiary type amine resin. This cationic epoxy resin, which contains ammonium group in the end of the polymer chain, was synthesized by ring-opening reaction of an epoxy resin with secondary amine in the presence of a proton donor. The so prepared cationic resin was dispersed in water, giving an emulsion containing charged polymer particles. A layer of resin was successfully electrodeposited on the phosphated stainless steel plate and physical properties of the layer were studied. A detailed study aiming to obtain reliable information of coating properties was carried out. The effect of a number of factors, including electrodeposition voltage, electrodeposition time, pH value of the emulsion, solvent content, resin Epoxy Equivalent Weight (E.E.W.) resin concentration, and bath temperature on deposition yield and coating adhesion was studied with a view to optimize these factors. Variables affecting the rupture voltage were also investigated.     

Synthesis and characterization of a new class of thermosetting resins: Allyl and propargyl substituted cyclopentadiene derivatives

A series of all-hydrocarbon resins were synthesized by reacting cyclopentadiene allyl chloride, propargyl chloride, or a mixture of allyl chloride and propargyl ide, under phase transfer conditions. Phase transfer reactions with and without added solvents, and with either quaternary ammonium or crown ether catalysts, yielded similar products consisting of a mixture of 1,1-disubstituted cyclopentadiene (minor amount) and 2-3 isomers each of tri-, tetra-, penta-, and hexa-substituted derivatives. No further reaction of each these components possible. The overall substitution pattern varied little with changes in reaction conditions although limiting the allyl chloride content led to still reactive, partially substituted products. Incorporation of all-propargyl and high propargyl-to-allyl mixed functionalities on cyclopentadiene yielded products whose stability was very hindering their thorough characterization. Preliminary evaluation was there-carried out for mixed resins with lower propargyl functionality. The allyl substituted resin (allylated cyclopentadiene, ACP) underwent thermal cure lout initiator at around 200°C while allyl/propargyl substituted resin (7:1 ratio, APCP) showed a faster, lower temperature cure at around 120°C. Cationic cure of ACP was also initiated by a novel sulfonium salt at around 100°C. Neat resin when cured at 200°C gave material with a flexural storage modulus 2 of about 300 MPa. Further cure at 250°C raised the modulus to 1.2 GPa. resin gave composites with excellent properties when used with glass and on fibers. Flexural modulus values (by DMA) of ∼ 66 GPa were obtained for ACP/carbon fiber composites compared with 42 GPa for epoxy/carbon composites made in our laboratories using commercially available materials. The modulus values at 300°C dropped to 10% of the room temperature value for the epoxy composites, while the ACP/carbon composite maintained 60% of its room temperature value at 300°C. When brought back to ambient temperature, the modulus of latter sample had increased to 80 GPa and that of the epoxy composite dropped to 23 GPa. Glass fiber ACP composites performed similar to an epoxy composite up to 200°C but maintained properties up to 300°C while those of the epoxy were drastically reduced. TGA analysis of both cured ACP resin and its composites showed decomposition beginning at 375°C. Three-point-bending tests indicated very high modulus with brittle failure for ACP composites. Scanning electron micrographs showed moderate bonding of the new resin to both carbon glass fiber surfaces. This new class of thermosetting resins offers excellent potential for application in low-cost glass and carbon composites with good thermal and physical properties.     

Coemulsion and electrodeposition properties of mixtures of cationic epoxy resin and cationic acrylic resin containing blocked-isocyanate groups

2-Ethylhexanol–half-blocked-toluene diisocyanate (2EH-half-blocked TDI) was first reacted with 2-hydroxyethyl methacrylate (HEMA) to prepare HEMA–TDI–2EH monomer containing blocked-isocyanate groups. This monomer was reacted with butyl acrylate, styrene, and N,N-dimethylaminoethyl methacrylate to prepare an acrylic copolymer III ′ containing blocked-isocyanate groups and tertiary amine groups. The acrylic copolymer III ′ can be mixed with an epoxy–amine adduct IV ′, acetic acid, and deionized (D.I.) water to from an electrodepositable coemulsion. The electrophoretic codeposition of the coemulsion and physical and chemical properties of the codeposited film were investigated. The resin composition of film deposited from coemulsion was determined by Fourier transform infrared (FTIR) quantitative analysis to study the coemulsion and electrophoretic codeposition behavior. The applicability of this two-component coemulsion in primer–surface (pricer) electrodepositable paint was also discussed. The results indicate that the deposition yield of cationic acrylic copolymer III is greater than that of cationic epoxy resin IV , i.e., the deposition velocity of III is faster than that of IV . However, resins III and IV can be well codispersed in D.I. water to form stable coemulsion; thus, the resin composition of deposited is almost equal to the resin composition. Moreover, the throwing power of coemulsion is almost equal to that of IV emulsion but greater than that of III emulsion. The optimum resin compositions of coemulsions for obtaining better gel content of deposited films are between 0.65 and 0.8 ( III/III + IV , by weight). © 1994 John Wiley & Sons, Inc.     

Synthesis of epoxy resins from alcohol‐liquefied wood and the mechanical properties of the cured resins

New wood‐based epoxy resins were synthesized from alcohol‐liquefied wood. Wood was first liquefied by the reaction with polyethylene glycol and glycerin. The alcohol‐liquefied wood with plenty of hydroxyl groups were precursors for synthesizing the wood‐based epoxy resins. Namely, the alcoholic OH groups of the liquefied wood reacted with epichlorohydrin under alkali condition with a phase transfer catalyst, so that the epoxy groups were put in the liquefied wood. The wood‐based epoxy resins and the alcohol‐based epoxy resins as reference materials were cured with polyamide amine. The glass transition temperature (Tg), the tensile strength, and the modulus of elasticity of the wood‐based epoxy resin were higher than those of the alcohol‐based epoxy resin. Also, the shear adhesive strength of the wood‐based epoxy resin to steel plates was higher than those of the alcohol‐based epoxy resins, which was equivalent to the level of petroleum‐based bisphenol‐A type epoxy resins. The higher Tg of the wood‐based epoxy resin than that of the alcohol‐based epoxy resin is one of the evidences that the wood‐derived molecules were chemically incorporated into the network structures. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

有机硅聚醚胺增韧改性环氧树脂的研究

采用端环氧基硅油及其聚醚胺预反应物、聚醚胺(D-230)来改性双酚A型环氧树脂(EP)。有机硅与聚醚柔性链段通过环氧树脂主链或固化剂键合到致密的环氧树脂交联网络中。系统研究了端环氧基硅油及其聚醚胺预反应物等对固化物的拉伸强度、断裂伸长率和冲击强度的影响。采用扫描电子显微镜对改性固化物的断裂面形态进行了分析。采用5份端环氧基硅油聚醚胺预反应改性EP后,其拉伸强度略有提高,断裂伸长率由38.62%提高到42.9%,冲击强度由20.23 kJ.m-2提高到25.89 kJ.m-2。依据其断裂伸长率与材料拉伸断面的SEM照片,环氧树脂固化物显示出明显的增韧效果,符合涂料用树脂基料的要求。