梳型UV固化水性聚氨酯树脂的制备与表征

通过引入含双键基团的中间体制备了分子链侧基、端基均含可UV固化基团的梳型水性聚氨酯树脂。采1用红外光谱仪FTIR、核磁共振仪H NMR、热重分析仪TGA等分析手段对样品的结构与性能进行了表征。分析表明,所得产品符合预期分子结构的设计,为半透明泛蓝光乳液,粒径细微均匀;固化层呈现2个快速失重温度区间。中间体的加入增强了固化层的耐溶剂性和硬度,附着力、拉伸强度和交联密度也得到提高。()()()     

Physical and thermal properties of UV curable waterborne polyurethane dispersions incorporating hyperbranched aliphatic polyester of varying generation number

Three series of novel waterborne hyperbranched polyurethane acrylates for UV curable aqueous dispersions (WHPUD) based on hydroxy-functionalized hyperbranched aliphatic polyesters Boltorn™ of varying generation number were investigated. The effects of the overall composition, including acidic and acrylate groups, and functionality of hyperbranched polyester were studied in terms of particle size, rheology, photopolymerization kinetics, dynamic mechanical thermal as well as thermal degradation behaviors of WHPUDs. The average particle sizes of aqueous dispersions, 43-134 nm, were determined by laser light scattering. The stability and particle size were dependent on the amount of carboxylic acid groups, degree of neutralization, and molecular structure. The rheological features have revealed that all dispersions belong to pseudoplastic fluids. The shear thinning behavior of WHPUDs is more pronounced for lower generation of hyperbranched polyester. The photopolymerization rates of the resins under UV irradiation in the presence of a photoinitiator showed an increasing trend with higher functionality of acrylate. The glass transition temperature (T_g) of UV cured films evaluated by dynamic mechanical thermal analysis (DMTA) showed that the influence of end capping by hard segment consisting of IPDI-HEA is remarkable due to the increase of crosslink density. The T_g, storage modulus and loss modulus increased with increasing generation number from the second to the fourth. The results of TGA for cured WHPUD films indicated good thermal stability with no appreciable weight loss until 200 °C, and that an increase in the hard segment content provoked the increases in thermal degradation temperature. This behavior is rationalized by relating crosslink density dependence of chain end concentration and the generation number of hyperbranched polyester.     

Effect of the hard segment on the properties of UV curable waterborne blocked polyurethanes

Two types of UV curable waterborne blocked polyurethanes (PUs) were obtained from 2,4-tolylene diisocyanate(TDI) and isophorone diisocyanate (IPDI), which had the same soft segments and different hard segments. The PUs contained both the UV curable C=C bond and the blocked NCO groups which could be de-blocked when heated. Effect of the hard segment on the properties of the two types of PUs was investigated. The FTIR spectra method was employed to confirm the structure of the PUs. The photo-DSC was used to study the photo-polymerization rate of the PUs under UV irradiation in the presence of a photo-initiator and the C=C conversion behaviors. Heating-up IR analysis was used to track the de-blocking process and the heat curing process. The thermal degradation analysis (TGA) was employed to investigate the thermal stability of the UV cured films before and after heat curing process. Dynamic mechanical properties of the UV and heat cured films were investigated by the dynamic mechanical thermal analysis (DMTA).     

Highly branched polyurethane acrylates and their waterborne UV curing coating

A series of UV curable highly branched waterborne polyurethane acrylates (BWPUAs) were synthesized using an “oligomeric A₂ + B₃” approach. The thiol-endcapped difunctional oligomeric A₂ was synthesized first by the addition reaction of isophorone diisocyanate, α,α-dimethylol propionic acid and 2-hydroxyethyl acrylate, then further underwent thiol-Michael reaction with 1,6-hexamethylene bis(thioglycolic acetate). Trimethylolpropane triacrylate was used as a B₃ monomer. The molecular structures were characterized with FT-IR and ¹H NMR spectroscopy. 1,6-Hexanediol diacrylate (HDDA) was incorporated into the polymeric chain for preparing the HDDA-modified BWPUAs (BWPUA-Hs). For the comparison, the linear waterborne polyurethane acrylate (LWPUA) was synthesized. The UV curing kinetics study results by using the photo-DSC approach showed that the BWPUAs possessed higher photopolymerization rate and final unsaturation conversion in the UV cured films compared with the LWPUA, which increased with the increase of unsaturation concentration in BWPUA. Moreover, the photopolymerization performance, and water and solvent resistance properties were greatly enhanced by the incorporation of HDDA segment into the BWPUA chain. The dynamic mechanical thermal analysis results showed that the elastic modulus in the rubbery plateau, and the glass transition temperature of UV cured film increased with increasing unsaturation concentration in BWPUA, whereas decreased with the introduction of HDDA flexible segment. The thermogravimetric analysis confirmed the high thermal stability of UV cured BWPUA films. All UV cured BWPUA and BWPUA-H films showed better flexibility and middle refractive indices due to the thioether linkage in the polymer network.     

一种高性能紫外光固化胶粘剂的制备

以异佛尔酮二异氰酸酯IPDI、改性聚醚多元醇、甲基丙烯酸羟乙酯(HEMA)为主要原料,制备了聚氨酯丙烯酸酯PU1。考查了水解剥离型紫外光固化胶粘剂的基本配方中各主要组分对粘接强度和水解剥离性能的影响。研究结果表明,PU1作为基础树脂玻璃粘接强度高同时剥离时间短分别为12.2 MPa和30 min;亲水性单体聚乙二醇二丙烯酸酯比单官能甲氧基聚乙二醇丙烯酸酯在粘接强度和水解剥离速度上优异。其中FA-260A均衡性最佳,玻璃粘接强度12.5 MPa,水解剥离时间20 min;高折射率、疏水性环状单体对基本配方的折射率的调节有帮助,可以实现胶粘剂折射率1.50的要求,其中低官能度邻苯基苯氧乙基丙烯酸酯性能最佳;溶剂选用环保型低级醇对水解剥离性能有帮助。()()     

水性光固化改性氯化聚丙烯的制备及性能

以丙烯酸(AA)和甲基丙烯酸羟乙酯(HEMA)对氯化聚丙烯(CPP)进行溶液接枝改性。考察了AA与HEMA两种单体总用量(AA与HEMA两种单体质量之和占CPP质量的百分数,下同)及引发剂用量(即引发剂质量占CPP及单体总质量的百分数,下同)对接枝率的影响,得到了最佳AA与HEMA总用量为20%,最佳引发剂用量为3%,在该条件下接枝率达到8.81%。然后以甲基丙烯酰氯对接枝改性CPP进行光固活性成分改性,研究了不同AA用量的水性光固化改性CPP乳液性能、表面张力及附着力。结果表明,AA用量占AA和HEMA总质量20%~50%,均能形成乳液,乳液粒径随AA用量增多而减小;水性化改性产物经光固活性成分改性后,以及经光固活性成分改性后的产物光固化前后,表面性能良好,表面张力均在40 m N/m以上,附着力得到提高。该材料符合环保要求,具有良好的应用前景。     

光/湿双固化聚氨酯热熔胶的制备与性能研究

以多元醇、异氰酸酯、含羟基丙烯酸酯和光引发剂等为原料,制备了PET(聚酯)基材粘接用光/湿双固化PU(聚氨酯)-PUA(聚氨酯丙烯酸酯)型反应性HMA(热熔胶)。研究结果表明:该HMA中同时含有可光固化基团(C=C)和可湿固化基团(-NCO);当n(C=C)∶n(-NCO)=20∶80、w(复合光引发剂)=1.5%~2.0%和引入甲基丙烯酸羟乙酯(HEMA)时,相应HMA具有较高的初始强度和最终强度;光/湿双固化HMA的透明度高于湿固化HMA,说明UV固化是增加光/湿双固化HMA透明度的主要原因。     

木材用湿固型聚氨酯胶粘剂的研制

以聚己内酯二醇(PCL)、聚己二酸丁二醇酯二醇(PBA)和二苯基甲烷4,4′-二异氰酸酯(MD I)等为主要原料制备了湿固型聚氨酯胶粘剂,研究了NCO质量分数、增粘树脂、催化剂和相对湿度等因素对聚氨酯胶粘剂性能的影响。     

The utilization of carbon nitride to reinforce the mechanical and thermal properties of UV-curable waterborne polyurethane acrylate coatings

The waterborne polyurethane-acrylate (WPUA and Wsi-PUA) oligomers were prepared by anionic self-emulsifying method, using isophorone diisocyanate (IPDI), polyethylene glycol (PEG), dimethylol propionic acid (DMPA), vinyl hydroxyl silicone oil (VHSO) and hydroxyethyl methyl acrylate (HEMA) as raw materials. Then, a series of UV-curable waterborne Wsi-PUA–C₃N₄ composites containing different content of g-C₃N₄ were obtained with oligomer and photoinitiator Darocur 1173. FTIR, XRD, TEM, SEM, and TGA were employed to investigate the structure, morphology and thermal property of the Wsi-PUA–C₃N₄ composite films. The effect of g-C₃N₄ content on the performance was also investigated. The mechanical performance, water resistance and gel content of UV-PUA films were measured. It was found that with g-C₃N₄ particle was introduced into Wsi-PUA oligomer, the hardness, tensile strength, gel content, water resistance and thermal stability of composite films were significantly augmented. Moreover, when the content of g-C₃N₄ was 1.0 wt.%, the UV-curable film had the best mechanical property. The obtained composite is promising for a number of applications, e.g., for protecting the surfaces of metal and wood.     

Rheological behavior of waterborne polyurethane/starch aqueous dispersions during cure

Isothermal rheological behaviors of waterborne polyurethane (WPU)/starch aqueous dispersions during cure were investigated with a small-amplitude oscillatory shear flow experiment to evaluate their crosslinked structure and to predict their mechanical properties, for the first time. An abrupt increase in the elastic storage modulus (G′), the viscous loss modulus (G″), the complex dynamic viscosity (η^*) and the loss tangent (tan δ) was observed during the curing process of the dispersions, as a result of the formation of a fractal polymer gel. The gel point (t_gel) was determined from the intersection in tan δ vs curing time for different constant shear frequencies, where tan δ was frequency independent and all curves crossed over, indicating the validity of the Winter–Chambon criterion for the complex system. The values of the power law exponent (n) and the gel strength (S_g) at the gel point indicated that with an increase of starch content the crosslinked WPU/starch gels underwent a transition from weak fractal to strong elastic ones. Moreover, the WPU/starch composite sheets, obtained from the aqueous dispersions with relatively high S_g values, also exhibited the increased tensile strength (σ_b) and Young's modulus (E). Their structure–mechanical properties relationship and the phase transitions of dispersed starch–dual-phase continuity–starch matrix were revealed. This work confirmed that the rheological characters could be used to predict the mechanical properties of the WPU materials blended with natural polymer.     

Abrasion resistance of waterborne polyurethane films incorporated with PU/silica hybrids

We describe polyurethane (PU)/silica hybrids (PSHs) prepared through hydrolysis and condensation reactions of tetraethoxysilane (TEOS) with or without methyltriethoxysilane (MTES) in the presence of polyurethane dispersion, which were subsequently incorporated into waterborne polyurethane (WPU) to prepare composites. The effects of the solid mass ratio of PSHs/WPU on the particle size of composite emulsions, the dispersion of silica nanoparticles in composite films, and the hardness and abrasion resistance of the corresponding films were examined. Composite emulsions possess a nanoscale particle size when incorporated with PSHs prepared using TEOS and MTES as precursors, and are superior to those with PSHs prepared using TEOS alone. Transmission electron microscopy revealed that silica nanoparticles had a uniform distribution in the polymer matrix and agglomerates could be almost completely avoided through in situ modification of silica with Si-CH₃ groups in the polyurethane dispersion. Composite films prepared with this method exhibited a superior hardness and abrasion resistance even at a lower silica content compared with that containing unmodified silica. In particular, optical microscopy and scanning probe microscopy observations demonstrated wear behavior differences among these composite films from the macro- and nanoscale viewpoints, respectively. It is proved that abrasive wear occurs, and surface morphology studies are in accordance with the results of abrasion resistance tests.     

聚氨酯丙烯酸酯软段结构对UV胶性能的影响

以几种不同结构的多元醇、异佛尔酮二异氰酸酯(IPDI)和丙烯酸羟乙酯为原料,合成了多种聚氨酯丙烯酸酯预聚物(PUA).按照同样比例的单体、引发剂及其他助剂配制成光固化胶粘剂(UV胶),考察了聚氨酯中多元醇结构对UV胶固化速度、黏结强度、胶膜性能等的影响.结果表明,聚氨酯结构中软段结构对UV胶粘剂性能影响比较大,合理地选...     

UV固化聚氨酯丙烯酸酯预聚体的合成及其性质

聚氨酯丙烯酸酯预聚体的制备是由二步反应完成,本文对预聚体合成过程中各种影响因素进行分析比较,确定最佳合成聚氯酯丙烯酸酯预聚体的工艺条件为：第一步反应温度为60-65℃,时间为4h,n(NCO)：n(OH)=3,催化剂为物料总量的0．4％,第二步反应温度为70．75℃,时间为4h。     

Development of waterborne UV-A curable clear coat for car refinishes

The development of a waterborne UV-A curable clear coat for car refinish application is described. The clear coat formulations are based on specially developed acryloyl or maleimide functional polyurethane dispersions. The functional PUR dispersions are characterized by a relatively low molecular weight, a high CC functionality and an optimized amount of poly(ethylene oxide). These characteristics are necessary for obtaining optimal film formation which results in good appearance and other film properties. It was found that poly(ethylene oxide) had a positive effect on surface cure when irradiated with UV-A light (less influence of oxygen inhibition). The synthesis of PUR dispersions and their performance in clear coats are described, including several aspects on film formation (conversion of CC, AFM measurements) and film properties (durability, physical and chemical properties).     

Flame retardancy and hydrolysis resistance of waterborne polyurethane bearing organophosphate moieties lateral chain

A novel halogen-free flame retardant diol bearing pendant organophosphate group, 2-ethyl-2-(2-oxo-5,5-dimethyl-1,3,2-dioxaphosphorinanyl-2-methylene)-1,3-propanediol (EPPD), was designed and synthesized, and then covalently conjugated into polyurethane as chain extender to prepare a series of phosphorus-containing flame retardant waterborne polyurethanes (PWPU). The chemical structures of the resultant EPPD and PWPU were confirmed by FTIR, ¹H and ³¹P NMR, respectively. Simultaneously, the flammability and thermal behavior of PWPU films were systematically investigated by limiting oxygen index (LOI) test, UL-94 vertical burning experiment and thermogravimetric (TG) as well as residual char analysis. An LOI value of 26.6% and a UL-94 V-0 rating can be achieved when the PWPU sample conjugated with 12 wt% EPPD, showing good inherent flame retardancy. TGA and residual char analysis indicate that the incorporation of EPPD induces a slight decrease of the thermal stability due to the relatively weaker bond energy of OPO, whereas the formed phosphoric and polyphosphoric acid during combustion can impart PWPU with nonflammability owing to the promoting of rugged carbonaceous char in the condensed phase which shields the underlying polyurethane from further attacking of heat flux. Meanwhile, hydrolytic stability study demonstrates that PWPU with organophosphate moieties linking in the side-chain exhibits better hydrolysis resistance than that with phosphoester bond conjugated in the backbone.     

不同硅氧烷改性水性聚氨酯胶膜的性能

以二苯基硅二醇(DPSD)、聚二甲基硅氧烷(PDMS和KF-2201)对水性聚氨酯(WPU)进行化学改性以改善WPU耐水性和耐热性的不足,并探究3种改性剂对WPU胶膜耐水性和耐热性的影响.利用DLS对乳液粒径分布进行测试,采用FTIR、XPS、DSC、TG、DTG、SEM、AFM对胶膜进行表征.未改性胶膜、DPSD、PDMS以及KF-2201改性胶膜的水接触角分别为81.08°、96.37°、105.72°、110.05°,吸水率分别为16.41％、12.70％、10.19％、9.12％,热失重95％时相应胶膜的温度分别为367、375、394、401℃,对应胶膜的粗糙度分别为1.81、3.67、5.06、17.7 nm.结果表明,硅氧烷的引入提升了胶膜的耐水性和耐热性,而含有大量Si—O—Si键和疏水苯环的KF-2201更有助于提升胶膜的耐水性和耐热性.此外,胶膜表面的纹路排列较为精细规整,并且胶膜软硬段存在微相分离.     

Properties and paper sizing application of waterborne polyurethane emulsions synthesized with isophorone diisocyanate

In this work, a two-step synthesis methodology has been used to synthesize a series of waterborne polyurethane (WPU) emulsions with isophorone diisocyanate (IPDI), poly-caprolactone diol (PCL) and dimethylol propionic acid (DMPA) as monomers and ethylenediamine (EDA) as the chain extender, respectively. The influences of the NCO/OH molar ratio, DMPA content, chemicals-adding sequence, and acetone content on the physical properties of the resultant emulsions have been investigated in detail. The results show that the emulsion viscosity increases with an increase in the NCO/OH molar ratio or DMPA content whereas it declines sharply as the acetone amount increases. The emulsion particle size is seen to increase with the NCO/OH molar ratio but it decreases as the DMPA content increases. The chemicals-adding sequence is observed to strongly affect the particle size and viscosity of the resultant emulsions. For cast films, with an increase in the NCO/OH molar ratio, the elongation monotonically decreases while the tensile strength is seen to increase at first and then deceases. The film water absorption capacity is found to go up as the DMPA content increases. Furthermore, after sized with the emulsions, the paper water resistance is markedly improved and the 30s Cobb value is seen to decrease by 63% as compared to the unsized counterpart. The paper folding resistance and the tensile index are also improved to certain extents. For producing well-performed WPU emulsions for sizing paper sheets, an NCO/OH molar ratio of 1.6–1.8 and a DMPA content of 6.0–7.0 wt.% are preferably chosen.     

水性聚氨酯胶膜的耐水性能研究

采用预聚体法,以聚酯多元醇、甲苯二异氰酸酯、二羟甲基丙酸(DMPA)制备了聚酯型水性聚氨酯乳液,考察了亲水扩链剂DMPA用量、NCO/OH值、中和剂的种类、中和度、扩链剂乙二胺用量对乳液涂膜耐水性的影响,制备了耐水性较好的水性聚氨酯乳液。