The influence of structural modification and composition of glycidyl carbamate resins on their viscosity and coating performance

The synthesis, characterization, and coatings performance of a series of glycidyl carbamate (GC) resins synthesized from a hexamethylene diisocyanate biuret resin, glycidol, and alcohols were explored. The partial replacement of glycidol with alcohols was explored as a way to reduce the viscosity of multifunctional GC resins. Six modified GC resins were obtained by replacing one-third of the glycidol with alcohols and ether alcohols. The modified GC resins were characterized using FTIR and ¹³C NMR. The alcohol-modified GC resins had significantly lower viscosity than that of the control GC resin. The effect of amount of alcohol modifier on resin viscosity was also studied by making a series of resins with different levels of modifier. Both amine-cured and self-crosslinked coatings were prepared from the resins. Coating properties such as hardness, impact strength, methyl ethyl ketone double rubs, flexibility, and adhesion were studied. Differential scanning calorimetry and thermogravimetric analysis were also used to study the thermal properties of the coatings. The resin structures and their coating performance showed an excellent correlation. The coating performance was found to be governed by the type of modifier, structural compositions of the modifier in the resins, type of amine crosslinkers, and techniques of crosslinking used.     

Novel water-dispersible glycidyl carbamate (GC) resins and waterborne amine-cured coatings

Water-dispersible glycidyl carbamate (GC) functional resins were synthesized and crosslinked using a water-dispersible amine to form coatings. GC functional resins are synthesized by the reaction of an isocyanate functional compound with glycidol to yield a carbamate (urethane) linkage (–NHCO–) and reactive epoxy group. The combination of both functionalities in a single resin structure imparts excellent mechanical and chemical properties to the coatings. Previous studies on the development of GC coatings have focused on solvent-borne coating systems. In this study, GC resins were modified by incorporating nonionic hydrophilic groups to produce water-dispersible resins. To determine the influence of the content of hydrophilic groups on dispersion stability, aqueous dispersions were made from a series of hydrophilically modified GC resins and characterized for particle size and dispersion stability. The composition of a typical, dispersed GC resin particle was predicted using Monte Carlo simulations. Stable GC dispersions were used to prepare amine-cured coatings. The coatings were characterized for solvent resistance, water resistance, hardness, flexibility, adhesion, and surface morphology. It was observed that GC resins were able to be dispersed in water without using any surfactant and by minimal mixing force (hand mixing) and produced coating films with good properties when crosslinked with a compatible waterborne amine crosslinker.     

Cure of secondary carbamate groups by melamine-formaldehyde resins

Melamine-formaldehyde (MF) resins have been used as crosslinkers for hydroxyl-functional coreactants in thermoset coatings for about 60 years. Crosslink densities of films prepared from oligomeric urethane polyols suggested that the methoxymethyl groups of MF resins could react with urethane groups (i.e., secondary carbamate groups) as well as reacting with hydroxyl groups. Co-reactants that contain secondary carbamate groups and no hydroxyl groups have been prepared with several types of backbone structures. Cure of such co-reactants by MF resins has been studied using a gradient oven with determination of impact resistance, solvent resistance, and hardness. Several formulations from these cure profile sets have been selected for crosslink density determinations by dynamic mechanical analysis (DMA). Crosslink densities of cured films are consistent with complete conversion of secondary carbamate groups at temperatures only slightly higher than those used for cure of hydroxyl groups. The -OH groups on certain acrylic polyols were converted to secondary carbamate groups. The original acrylic and the converted acrylic were both cured with MF resins. Acid resistance was much better for films prepared from the acrylic that contained secondary carbamate groups. Presented at the 25th International Waterborne, High-Solids, and Powder Coating Symposium, New Orleans, LA, Feb. 18–20, 1998. 730 Worcester Street, Springfield, MA 01151.     

Synthesis,characterization and self-crosslinking of glycidyl carbamate functional resins

Multifunctional glycidyl carbamate functional resins were synthesized, characterized, and self-crosslinked coatings were prepared and characterized. Coatings based on glycidyl carbamate (GC) functional oligomers are attractive because they combine polyurethane properties with epoxide reactivity. The glycidyl carbamate functional resins were synthesized via reactions of the biuret adduct and isocyanurate trimer of hexamethylene diisocyanate (HDI) with glycidol. Resins were characterized using gel permeation chromatography (GPC), Fourier transform infrared (FTIR) spectroscopy and ¹³C NMR spectroscopy. Coatings were prepared to study the self-crosslinking reaction without additional hardener. Self-crosslinked coatings had an excellent combination of solvent resistance, good hardness and high impact resistance. The glycidyl carbamate resin from the biuret isocyanate adduct (BGC) was found to be more reactive during cure than glycidyl carbamate from the isocyanurate isocyanate trimer (IGC) as determined by hardness, solvent resistance, and T_g measurements. Thermogravimetric analysis (TGA) of the resins did not show thermal decomposition below 250 °C.     

Organic–inorganic hybrid coatings prepared from glycidyl carbamate resins and amino-functional silanes

Organic–inorganic hybrid coatings were prepared from glycidyl carbamate (GC) functional oligomers and different amino-functional trimethoxysilanes via a systematic three-step reaction process. Initially, glycidyl carbamate functional oligomers isocyanurate glycidyl carbamate (IGC) and biuret glycidyl carbamate (BGC) were synthesized from the reaction of the polyisocyanurate of hexamethylene diisocyanate (HDT) with glycidol and the biuret adduct of hexamethylene diisocyanate (HDB) with glycidol, respectively. Then, the GC resins were mixed with 3-aminopropyl trimethoxysilane (APTMES), N-(2-aminoethyl) 3-aminopropyl trimethoxysilane (AEAPTMES) and p-aminocyclohexyl methane (PACM) at different stoichiometric ratios. In order to form the hybrid organic–inorganic networks, the materials were cured either at room temperature and humidity for more than 20 days or with an additional heat treatment at 80 °C for 1 h and then keeping the coatings at room temperature and humidity for more than 10 days. The observable change in the structure during network formation was monitored by FTIR spectroscopy. The cured coatings were characterized by thermogravimetric (TGA) and differential scanning calorimetry (DSC). Atomic force microscopy (AFM) was used to characterize the surface properties of the hybrid systems. AFM observation suggests the phase separation behavior. Coating properties such as König pendulum hardness, crosshatch adhesion, MEK double rub resistance and water contact angle of the coatings were also evaluated. Finally, structure–property relationships are given based on the variable parameters used.     

Study of cationic UV curing and UV laser ablation behavior of coatings sensitized by novel sensitizers

To improve the laser ablation performance of cycloaliphatic epoxide cationic UV curable coatings, two novel reactive sensitizers were synthesized and characterized and their effect on coating properties examined. The sensitizers were synthesized based on the reaction between naphthalene or anthracene derivatives and monomers or oligomers used in the coating system. HPLC and GC-MS confirmed the formation of the desired products. Three coating systems based on cycloaliphatic epoxide with either oxetane or polycaprolactone polyol were formulated with the reactive sensitizers. The sensitized coatings had higher conversion during UV curing in the oxetane containing formulation and did not deter the curing in the polyol containing formulation. Better UV laser ablation performance was observed in all sensitized coatings compared to the controls. Coatings with the anthracene based sensitizer even had better laser ablation performance than a commercial polyimide. The sensitized coatings had higher hardness, T_g and crosslink density while the adhesion and solvent resistance were not affected. An optimal amount of sensitizer was found for each coating formulation in terms of UV curing behavior. The relationship between coating T_g and laser ablation behavior was investigated and it was found that the higher the T_g and crosslink density, the poorer the laser ablation performance.     

Linear glycidyl carbamate (GC) resins for highly flexible coatings

An approach to the design of highly flexible coatings based on glycidyl carbamate (GC) chemistry is presented. In past work, GC resins had been synthesized by reacting polyisocyanates such as hexamethylene diisocyanate biuret or hexamethylene diisocyanate isocyanurate resins with glycidol. When crosslinked with amines, due to their high functionality, these resins form very hard and tough coatings, but the coatings have limited flexibility. To obtain coatings with good flexibility, several GC resins were synthesized using linear and cycloaliphatic diisocyanates and a combination of diols and triol with glycidol. The combination of linear diisocyanates and diols introduces a more linear structure in the GC resin compositions. Crosslinked coatings were obtained using two amine crosslinkers, para-aminocyclohexyl methane (PACM) and a commercial polyamide, Ancamide-2353 (A-2353). The flexibility of the coatings was characterized using reverse impact test, GE impact test, and elongation at break in tensile test. The coatings were further characterized to determine their chemical resistance, hardness, thermal stability, and corrosion resistance. The diisocyanate composition and composition of diols and triol influenced the performance of the coatings. In order to understand the influence of the composition of the GC resins on their performance, coatings were characterized using differential scanning calorimetry and dynamic mechanical analysis.     

Synthesis,characterization and end-use evaluation of epoxy resins prepared from diallyl and dipropyl bisphenol A

We have synthesized 2,2'(6')-diallyl-4,4'-isopropylidenediphenol (diallyl bisphenol A), 2,2'(6')-dipropyl-4,4'-isopropylidenediphenol (dipropyl bisphenol A), and epoxy resins (glycidyl ether oligomers) of different average molecular weights. The acrylic and methacrylic esters were prepared by reacting the epoxy resin with acrylic and methacrylic acids, respectively. The amine-cured epoxy resins showed promise as general-purpose adhesives, while the epoxy acrylates were found to be useful as reactive oligomers in ultraviolet (UV) radiation curable coatings, and the epoxy methacrylates as anaerobic adhesives.     

Organic–inorganic hybrid coatings prepared from glycidyl carbamate resin, 3-aminopropyl trimethoxy silane and tetraethoxyorthosilicate

Hybrid sol–gel coatings were formulated from glycidyl carbamate (GC) resins, 3-aminopropyltrimethoxy silane (APTMS) and tetraethoxyorthosilicate (TEOS) as the inorganic network former. GC and silane-modified GC resins were synthesized and then characterized using Gel Permeation Chromatography (GPC), Nuclear Magnetic Resonance Spectrometry (NMR) and Fourier Transform Infrared Spectroscopy (FTIR). The resins were crosslinked with amine crosslinkers such as p-aminocyclohexyl methane (PACM), Ancamide 2050, Ancamide 2353 and Epikure 3164 at 1:1 equivalent ratio of the epoxy groups in the synthesized resin and amine crosslinker. The TEOS content in the coatings were varied to understand its effect on the coating properties. The hybrid coatings were cured at room temperature and humidity for more than 20 days as well as oven cured at 80 °C for 1 h. The thermal properties of the post-cured hybrid materials were evaluated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Mechanical property evaluation such as König pendulum hardness measurement, impact resistance and crosshatch adhesion tests of the post-cured samples were carried out. MEK double rub resistance and water contact angle of the coatings were also evaluated. All of the coatings had good adhesion to aluminum 2024-T3 and had good MEK double rub resistance, indicating good crosslinking. Properties such as T_g, hardness and flexibility varied with the amine crosslinker used with Epikure 3164 yielding the lowest T_g, highest flexibility, and lower hardness coatings. Increasing the amount of TEOS modification in the formulations increased the hardness, the T_g, and the thermal stability. The flexibility – determined using reverse impact measurements – also increased with increasing TEOS content.     

衣康酸光固化树脂的研究进展

被誉为"绿色技术"的光固化技术,不仅节能环保而且经济高效,已在众多领域得以应用.利用天然可再生资源制备光固化树脂对光固化技术的可持续发展具有重要意义.衣康酸作为一种来源广泛的天然可再生资源,其分子结构中同时含有不饱和双键和两个羧基,可替代丙烯酸、己二酸等石化资源合成各种光固化不饱和树脂,所得树脂综合性能优良.本文综述了...     

Hybrid coatings from novel silane-modified glycidyl carbamate resins and amine crosslinkers

Organic–inorganic hybrid coatings were prepared using silane-modified glycidyl carbamate resins and different amine crosslinkers via the sol–gel process. Two different silane-modified glycidyl carbamate resins with 33% and 20% silane modification were prepared. The synthesized resins were crosslinked with amine crosslinkers such as Amicure PACM, Ancamide 805, Ancamide 2050, Ancamide 2353, Epicure 3164, Jeffamine D-400, etc., at different epoxy to amine equivalent ratios. The formulated hybrid coatings were cured at laboratory temperature and humidity for more than 20 days and subjected to different tests. The hybrid coatings were analyzed using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) during network maturation. Post-cured coatings were also analyzed to understand the effect of structural variables on the coatings thermal properties. Mechanical testing of the post-cured coatings such as König pendulum hardness, crosshatch adhesion and impact resistance were also evaluated. Solvent resistance of the coatings was evaluated by of testing the methyl ethyl ketone (MEK) double rub resistance. Atomic force microscopy (AFM) was used to characterize the surface topography of the hybrid coatings. Finally, structure–property correlations were given based on the observed results.     

Synthesis and application of novel UV-curable hyperbranched methacrylates from renewable natural tannic acid

With a view to developing high performance UV curable coatings with high renewable contents, acrylated epoxidized soybean oil (AESO) was combined with a novel kind of biorenewable tannic acid-based hyperbranched methacrylates (TAHAs). The TAHAs were synthesized by ring-opening reaction of glycidyl methacrylate (GMA), glycidyl ester of Versatic acid (CE10) and natural tannic acid (TA). The epoxy groups of GMA and CE10 were involved in the ring-opening reaction with the hydroxyl groups of TA while residual methacrylate groups can carry out photopolymerization. By controlling the ratio of GMA and CE10, TAHAs with varying degree of methacrylate groups have been prepared. The synthesized TAHAs were formulated into acrylated epoxidized soybean oil (AESO) based UV curable coatings to produce the biorenewable materials based UV curable coatings. The effects of TAHAs on AESO coated film properties of pendulum hardness, flexibility and adhesion were investigated. Mechanical properties, thermal properties and biodegradability of the cured films were also evaluated. With the incorporation of TAHAs, the hardness, adhesion, tensile strength of the cured coating films were remarkably improved, which were attributed to the unique structure of hyperbranched methacrylates. Meanwhile, the biorenewable content was not greatly decreased due to the biorenewable character of tannic acid in TAHAs. These results showed that TAHAs as efficient toughening agents could produce UV-curable coatings of balanced coating performance with reasonably high biorenewable content. Moreover, the environment degradability of AESO-based cured films was also enhanced after the addition of TAHAs.     

Design and synthesis of bio-based UV curable PU acrylate resin from itaconic acid for coating applications

UV curable PUA resin was successfully synthesized from polyol based on sustainable resource originated from itaconic acid (IA), isophorone diisocyanate (IPDI) and 2-hydroxyethyl methacrylate (HEMA). A polyol was synthesized by condensation reaction of IA with 16-hexanediol in the presence of p-Toluenesulfonic acid (pTSA). The synthesized PUA resin was characterized for its structural elucidation by using Fourier Transform Infrared Spectrophotometer (FTIR), ¹H and ¹³C NMR spectroscopy. The synthesized UV curable PUA resin was incorporated in varying concentrations in conventional PUA coating system. The effects of varying concentration of synthesized UV curable PUA resin on rheology, crystallinity, thermal and coating properties were evaluated. The rheological behavior of the resins were evaluated at variable stress and result showed decrease in viscosity of resin as concentration of synthesized UV curable PUA resin increases in conventional PUA resin. The cured coatings have been evaluated for glass transition temperature (T_g) and thermal behavior by differential scanning calorimeter and thermogravimetric analysis respectively. The degree of crystallinity of the coatings was determined from X-ray diffraction patterns using the PFM program. It was found that increase in the mass proportion of IA based PUA in coatings, the coating becomes more rigid and crystalline. The synthesized UV curable PUA coatings showed interesting mechanical, chemical, solvent and thermal properties as compared to the conventional PUA. Further, cured coatings were also evaluated for gel content and water absorption.     

Tuning the mechanical performance and adhesion of polyurethane UV cured coatings by composition of acrylic reactive diluents

An approach to modify the properties of UV curable polyurethane coatings by altering the amount and functionality of acrylic reactive diluents, in order to optimize the coating performance, is demonstrated. Based on the rheology analysis, a model of the rheological behavior of the UV curable materials depending on the amount and type of a reactive diluent in the composition is demonstrated in this study. The relationships between the rheological behavior, the mechanical properties and adhesion of the coatings prepared from polyurethane UV curable compositions containing different amounts and functionalities of acrylic reactive diluents, have been investigated and discussed in this study. Based on the results of the study, the desired properties of UV cured coatings can be modeled and controlled without changing the nature of a particularly selected oligomer, thus maintaining the advantages of its chemical structure in a coating composition.     

Low VOC carbamate functional coatings compositions for automotive topcoats

Polymers and oligomers having carbamate functional groups have been used in a variety of curable coating compositions. Carbamate functional polymers offer many advantages for automotive topcoats, such as outstanding resistance to environmental etching, scratching and marring, humidity, and UV exposure. Hydrophobic carbamate oligomers suitable for crosslinking with standard amino resins were synthesized and formulated into stable one-pack automotive clearcoats with low volatile organic compound (VOC) and excellent physical properties. Because of their unusually steep thermal viscosity curves, these oligomers are particularly adaptable to hot spray techniques that enable coatings in the 85–90% weight solids range to be applied with conventional electrostatic mini-bells. Presented at the 27th Annual International Waterborne, High-Solids, and Powder Coatings Symposium, in New Orleans, LA, March 2000. Automotive Coatings Technical Center, Southfield, MI 48034.     

低温固化GMA丙烯酸粉末涂料的开发与应用

对环氧丙烯酸树脂进行改性,并用二元羧酸固化,通过混合、熔融挤出、磨粉、过筛制得适合塑料底材涂装的120 ℃低温固化环氧基丙烯酸粉末涂料。与红外固化方式相结合,可缩短固化时间。对聚丙烯材质的汽车保险杆进行表面处理后,将低温固化环氧丙烯酸粉末涂料涂装在表面处理过的汽车保险杆上,提高涂层在保险杠上的附着力。检测结果表明:涂层具有优异外观、附着力和耐候性,降低了目前保险杠涂装时的VOC排放。     

氧抑制剂与分子流动性的关系:残余双键是影响初始粘度的函数(英文)

透明涂料的双重固化(热固化和UV固化)为层面涂装和汽车的更多特种部件的发展提供了巨大的发展前景。因为其可能解决紫外固化的屏蔽区的固化不完全的问题[1]。在先前的论文中,已经证实了UV光张度(辐射密度,I0)对暴露膜表面和丙烯酸酯中分子结构的双键转换的深层断面的氧抑制作用的影响[2～6]。近期的研究评价了具有不同玻璃化温度的固态聚合物基体对丙烯酸酯结构中双键转换的影响。探讨了UV固化配方和双重固化配方之间比较的一种直接判断的性能。研究中所使用的固态聚合物基体包括:聚甲基丙烯酸甲酯(PMMA,Tg114℃,平均重均分子质量 MW120000)和聚甲基丙烯酸丁酯(PBMA,Tg15℃,MW=337000)。通过改变单体和齐聚物混合物的分子质量的比以及固态聚合物基体的总含量,调整有氧存在或无氧存在的暴光时间(即固化速度)来进行研究工作,对于这个双重固化配方还用恒定的UV能量辐射评价了残余双键。用FTIR证实了剩余双键。讨论了紫外固化和双重固化配方的自游基迁移性和氧抑制作为配方体系粘度的功能函数。这些研究工作是基础性的而且是非常重要的。其目的是探索双重固化透明涂料的工业应用。     

叔胺型聚氨酯丙烯酸酯的合成和光固化性能

以三羟甲基丙烷三丙烯酸酯和二乙醇胺为原料,通过Michael加成反应合成叔胺型丙烯酸酯(NTM),再与异佛尔酮二异氰酸酯和丙烯酸羟乙酯反应制备叔胺型聚氨酯丙烯酸酯(APUA)。用HPLC、1HNMR、FI-IR和GPC对NTM和APUA进行了分析和表征。结果表明,将APUA作为预聚物用于以二苯甲酮为引发剂的紫外光固化涂料中,参与涂料体系光聚合,可克服涂料紫外光固化过程中的氧阻聚效应,提高C C双键转化率;加入质量分数为20%和40%的APUA,在光照160 s时,涂料中的C C双键转化率从15%分别提高到了71%和89%。     

Preliminary investigation of the impact of polymer composition on electrochemical properties of coatings as determined by electrochemical impedance spectroscopy

The influence of structural and systematic compositional variations in glycidyl carbamate (GC) functional polymers on the electrochemical properties of their coatings was studied. There are few reports which focus on the correlation of structural and compositional variations in polymer films with their electrochemical barrier properties, diffusion properties with regards to water and aqueous electrolytes, and corrosion performance. To begin to fill this knowledge gap, two sets of GC functional polymers were studied. The polymer compositions were designed to vary the extent of polar hydrophilic groups, non-polar hydrophobic groups, and reactive epoxy groups in the final coatings. Impedance responses of the coatings were found to be closely related to the structural and compositional variations of these GC polymer films. In addition, single frequency EIS experiments were used in an attempt to understand the water uptake behavior of these polymer films using NaCl solution and ionic liquid under immersed condition. The resulting transport property data of the films was correlated to their polymer structure and composition. Moreover, a novel attempt at ranking the stability of coating using capacitance measurement during a cyclic wetting–drying condition was also attempted. The information obtained from this work can potentially be used to optimize the polymer for the specific performance properties needed in the protective coating applications, saving significant time and effort in the research and development stage.     

Novel approach to convert non-self drying palm stearin alkyds into environmental friendly UV curable resins

UV curable coating is a form of green technology that reduces or eliminates completely the emission of volatile organic compounds (VOC) and is in line with the current global call in preserving nature. The objective of this project is to produce UV curable resins from non-self drying palm stearin alkyds by the incorporation of maleic anhydride (MAH) which could introduce more unsaturation into the main chains of alkyds. Four alkyds with different level of unsaturation were prepared and the successful incorporation of MAH was confirmed by FTIR and ¹H NMR analyses. Methyl methacrylate (MMA) was used as the reactive diluents, and benzophenone as the UV-photoinitiator. The UV-cured coatings were tested using standard methods adopted from ASTM, and results showed that coatings of maleated alkyds exhibited good film properties. This novel approach has succeeded in converting a non-self drying palm stearin alkyd into UV-curable resins.