Mechanistic studies in tackified acrylic emulsion pressure sensitive adhesives

Twenty‐three wt % aqueous tackifier dispersion based on glycerol ester abietic acid (T_g = 64°C, M_w = 940) was added to emulsion polymer 50/32/15/3 poly(2‐ethyl hexyl acrylate‐co‐vinyl acetate‐co‐dioctyl maleate‐co‐acrylic acid) pressure sensitive adhesive (PSA). From these latices, 25 μm thick films were cast. The films were dried at 25°C for 24 h or at 121°C for 5 min. Dynamic mechanical analysis (DMA) of the films included measuring elastic modulus (G′) and damping factor (tan δ). Under the above drying conditions, the films did not produce significant differences in their DMA and PSA properties as measured by loop tack, peel, and shear holding power. DMA of the tackified acrylic film showed thermodynamic miscibility between the tackifier and polymer regardless of the drying conditions. Microgels formed during emulsion polymerization of the acrylic PSA brought inherent weakness to the tackified film properties. In the neat acrylic PSA film, these discrete networks entangled with the uncrosslinked chains while in the tackified film, these networks could not form entanglements due to the increased molecular weight between entanglements for the uncrosslinked chains. This lack of network entanglements caused shear holding power of the tackified acrylic PSA film to be 4× lower than that of the neat acrylic PSA film. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1965–1976, 2000     

用AMPS合成高耐水性丙烯酸乳液压敏胶的研究

运用可聚合乳化剂AMPS和极少量低分子化剂CO－436相配合,采用特殊工艺的半连续无皂乳液聚合方法,研制出了一种耐水性较好的丙烯酸乳液压敏胶,并就其各种性能及影响因素进行了考查,结果表明,聚合工艺对AMPS乳液的聚合稳定性有较大影响,用可聚合乳化剂AMPS合成的丙烯酸乳液压敏胶具有较好的耐水性。     

医用丙烯酸酯乳液压敏胶的研制

叙述了医用丙烯酸酯乳液压敏胶的合成与性能。并且讨论了软、硬单体配比,宫能单体含量及乳化剂用量等因素对压敏胶粘度、快粘力、持粘力、剥离强度等性能的影响。     

Molecular parameters and their relation to the adhesive performance of emulsion acrylic pressure‐sensitive adhesives. II. Effect of crosslinking

Acrylic emulsion pressure‐sensitive adhesive (PSA) films generally have much lower shear holding power than that of their solvent‐borne counterparts for the same peel and tack. This is due to their discrete microgel morphology in the film. In contrast, film cast from solution‐polymerized acrylic PSA forms a continuous network as a result of crosslinking acrylic acid and aluminum acetyl acetonate (AAA) in the film following the solvent evaporation. Novel acrylic emulsion PSA was made by copolymerizing ≤1 wt % isobutoxy methyl acrylamide (IBMA) in the polymer backbone. The IBMA grafted the linear portion of the acrylic polymer with the microgels upon heating the film, which resulted in a significant increase in the shear holding power. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 2558–2564, 2001     

乳液型丙烯酸酯压敏胶研究进展

针对乳液型丙烯酸酯PSA(压敏胶)的耐水性较差、耐高温性欠佳及涂布干燥速率较慢等弊病,综述了乳液型丙烯酸酯PSA的最新研究方向及进展(包括高固含量乳液型丙烯酸酯PSA、乳液型交联丙烯酸酯PSA、低表面能材料粘接用乳液型丙烯酸酯PSA和耐水性乳液型丙烯酸酯PSA等);最后对其应用前景进行了展望。     

Molecular parameters and their relation to the adhesive performance of acrylic pressure‐sensitive adhesives

Model acrylic pressure‐sensitive adhesives (PSAs) based on poly(2‐ethyl‐hexyl acrylate‐stat‐acrylic acid) and poly(n‐butyl acrylate‐stat‐acrylic acid) at 97.5/2.5 wt % were synthesized using semicontinuous emulsion and solution polymerizations. Microgels formed in the lattices retained their discrete network morphology in the film. In contrast, acrylic solution was essentially gel free and crosslinking in the film was provided by the reaction of acrylic acid and post added Al Acetyl Acetonate after solvent evaporation, which led to continuous network morphology. The difference in film network morphology caused significantly lower shear holding power for the film from emulsion PSA compared with that of solvent‐borne film. Unlike shear holding power, loop tack and peel of acrylic PSAs were mainly controlled by the same sol/gel molecular parameters, regardless of emulsion or solution PSAs. The important molecular parameters are sol‐to‐gel ratio, entanglement molecular weight, weight average molecular weight, and to a lesser extent, glass transition temperature. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 2230–2244, 2001     

丙烯酸酯类乳液胶粘剂的研究进展

综述了丙烯酸酯类乳液胶粘剂的合成、改性、应用等方面的研究进展。在合成方面,讨论了主要组分的作用及影响因素,在性能方面阐述了改性的方法,并简述了丙烯酸酯乳液胶粘剂的用途。     

无皂丙烯酸酯乳液压敏胶的制备与性能研究

采用种子半连续乳液聚合的方法,将一种新型的可聚合离子单体烯丙氧基羟丙基磺酸钠（COPS-1）引入到聚合体系中,制备了稳定的无皂丙烯酸酯乳液.X射线光电子能谱（XPS）分析表明,COPS-1参与乳液共聚后,在乳液的干燥成膜过程中不易向胶层表面迁移富集.与常规的乳液压敏胶相比,该无皂乳液压敏胶具有良好的耐水性和压敏胶粘性能.     

Adhesion performance of UV-cured semi-IPN structure acrylic pressure sensitive adhesives

UV-curable solvent-free pressure sensitive adhesives (PSAs) are gaining importance in the area of adhesives because of increasing environmental concerns and the goal to reduce volatile organic compounds (VOCs) in work areas and consumption places. These PSAs have advantages such as low emission of VOCs, a solvent-free process, a fast producton rate at ambient temperature and only a modest requirement for operating space. In this study, UV-curable PSAs were investigated by measuring their adhesion performance in terms of probe tack, peel strength, shear adhesion failure temperature (SAFT) and holding power. PSAs were synthesized from 2-ethylhexyl acrylate (2-EHA), acrylic acid (AA) and vinyl acetate (VAc), using variations in AA concentration to control the glass transition temperature (T _g) of the prepared PSAs. In addition, two types of trifunctional monomers, trimethylolpropane triacrylate (TMPTA) and trimethylolpropane ethoxylated (6) triacrylate (TMPEOTA), which have different chain lengths, were used to form semi-interpenetrating polymer network (semi-IPN) structures after UV exposure. With increasing AA concentration in the PSAs, both the T _g and viscosity increased. Also, probe tack and SAFT increased, but peel strength decreased. After UV irradiation, probe tack decreased, and SAFT and peel strength increased as AA concentration increased in the PSAs. In most cases, cohesive failure changed to interfacial failure after UV exposure. Also, TMPTA increased the cohesion of PSAs; however, TMPEOTA affected the mobility of PSAs due to the different chain lengths of the two types of trifunctional monomer in a different way. The increase of TMPEOTA content diminished the cohesion of PSAs. Consequently, the adhesion performance of the PSAs was closely related to the T _g of the PSAs, and the two types of trifunctional monomer showed different adhesion performances.     

喷胶棉黏合剂纯丙乳液的研制

采用预乳化半连续种子乳液聚合工艺制备了用于喷胶棉黏合剂纯丙乳液.用单因素实验的方法,探讨了复合乳化剂用量、复合乳化剂配比、引发剂用量、交联剂用量、反应温度和反应时间等因素对该纯丙乳液性能的影响,并确定了最佳工艺条件.结果表明,软硬单体质量比为2.2∶1,乳化剂用量为3.5％,复合乳化剂配比为2∶3,引发剂用量为0.7％,交联剂用量为1.75％,反应温度为78～85℃,反应时间为150min,搅拌速率为250r/min时,得到的纯丙乳液耐水性和柔韧性能最佳.     

氧化还原引发聚合丙烯酸酯乳液及胶粘剂的研究

主要探讨了氧化还原引发剂用量对聚合反应速度、单体转化率的影响。同时对乳化剂用量,湿润剂种类用量,增粘乳液对乳液胶粘剂的性能的影响也进行了分析。研究发现:适宜的氧化还原引发体系的用量在单体的0．3％-0．8％之间;复合乳化剂用量为总量的2％-4％之间;LSR-101湿润剂为单体总量的0．5％-1．7％;增粘乳液用星为25％时,可得到转化率高,粘接性能良好的胶粘剂。     

丙烯酸酯压敏胶粘剂的紫外光交联技术研究

通过将交联单体甲基丙烯酸环氧丙酯共聚引入到丙烯酸酯主链结构中,用二芳基碘Ｗｅｎｇ六氟锑酸盐在紫外光激发下引发环氧基交联,从而制得一种综合性能优良的紫外光交联型压敏胶粘剂,并且系统研究了紫外光剂量,光引发剂用量,交联单体用量等因素对压敏胶综合性能的影响。结果发现紫外光交联是提高压敏胶持粘强度和耐温性能的一种有效手段。     

Optical properties and adhesion performance of optically clear acrylic pressure sensitive adhesives using chelate metal acetylacetonate

Optically clear acrylic pressure-sensitive adhesives (PSAs) with different co-monomers were synthesized. This study employed metal chelate aluminum acetylacetonate and zirconium acetylacetonate as curing agents. The optical properties of the acrylic PSAs were examined by UV–visible spectroscopy and a prism coupler. In addition, the adhesion performance was obtained by assessing the peel strength, the tack, and the shear adhesion failure temperature. The decrease in the adhesion performance may be related to a higher crosslinking density, which also resulted in a higher gel content.     

聚合工艺对丙烯酸酯乳液胶粘剂性能的影响

主要研究了聚合工艺对丙烯酸酯乳液胶粘剂性能的影响 通过对乳液胶粘剂的各种性能测试,发现3种聚合方法中,种子乳液聚合法制备的乳液胶粘剂的综合性能较为理想 采用种子乳液聚合法,最佳聚合工艺为:单体的滴加时间4h、聚合温度50℃、搅拌速率80 r/min     

纸塑复合用丙烯酸酯乳液胶粘剂的制备

采用半连续法制备了一种纸塑复合用丙烯酸酯乳液胶粘剂,讨论了乳化剂的用量、松香乳液的用量、交联剂的用量等因素对胶粘剂性能的影响。结果表明,当乳化剂的用量为4.5%、松香乳液用量为10%,胶粘剂的性能较好;另外,加入一定量的交联剂,可显著提高该胶粘剂的耐水性。     

高固含、低粘度丙烯酸乳液压敏胶工业化生产中粘度控制讨论

对高固含、低粘度丙烯酸乳液压敏胶工业化生产过程中粘度控制及成品贮存稳定性进行了讨论与观察。     

Rheology of acrylic dispersions for pressure sensitive adhesives

Pressure sensitive adhesives (PSA) can be defined as adhesive materials which, when dry, possess a lasting and aggressive tack which enables them to adhere to a wide variety of substrates, upon contact. The interest in aqueous acrylic dispersions PSA grew with the need to solve solvent emission problems. The theological characteristics of these PSA dispersions are important for the coating machinability whilst the rheological characteristics of the dried PSA dispersions are important for the performance of the adhesive systems. The rheology of these dispersions, which are generally applied at a concentration in the range of 50% dry material, is influenced by parameters such as particle size, the nature of the acidic monomers, the method of introduction of the acidic monomers, the addition of thickeners and many others which are not covered in this paper. The flow characteristics (shear stress versus shear rate) of these dispersions can be described by means of mathematical models and therefore characterized by a limited number of parameters. The adhesive test methods commonly used today are largely the result of empirical attempts to characterize adhesive performance under actual conditions. The more-common tests are used in order to quantify tack, adhesion and cohesion. We have defined some testing methods in order to characterize the viscoelasticity of the PSA (dynamic measurements at different temperatures and frequencies and creep measurements at different temperatures). We have correlated these rheological parameters to the adhesive performances and the molecular characteristics of the acrylic copolymer used.     

耐热性乳液型丙烯酸酯压敏胶的合成

采用种子乳液聚合法合成丙烯酸酯压敏胶,利用自交联单体N-羟甲基丙烯酰胺（NMA）提高其耐热性能,并采用反应型乳化剂DNS-86进一步提高压敏胶综合性能。研究了不同软硬单体用量比和功能单体配比对压敏胶性能的影响,探讨了自交联功能单体用量压敏胶耐热性能的影响,讨论了反应性乳化剂用量对压敏胶性能的贡献。结果表明：以最佳配方所制备出的乳液型压敏胶,其180°耐热剥离强度达到220N／m,耐热初粘力为11号钢球,耐热持粘力大于36h,固体质量分数为50％,粘度为460mPa·s。     

乳液型聚丙烯酸酯医用压敏胶的改性研究

分别采用多步乳液聚合法和乳液共混法改性制备粘接性能较好的乳液型聚丙烯酸酯医用压敏胶。分析讨论了种子乳液的组成、预溶胀时间和预溶胀次数、引发剂种类、原位聚合温度等因素对压敏胶粘接性能的影响。结果表明,多步乳液聚合法是全面提高粘接性能的有效方法;而基于预乳化半连续聚合工艺的乳液共混法,仅在一定范围内有改性效果。     

Influence of selected photoinitiators on important properties of photoreactive acrylic pressure‐sensitive adhesives

Photoreactive solvent‐borne pressure‐sensitive adhesives are not commercially available in the market. The reason for it is that the UV‐initiated crosslinking has sense only in the case of solvent‐free self‐adhesive systems. Investigations conducted in Institute of Chemical Organic Technology have shown that the photoreactive solvent‐borne acrylic PSA are conventional crosslinked solvent‐borne acrylic PSA used as crosslinking agents typical metal chelates as titanium acetylacetonate (TiACA), aluminum acetylacetonate (AlACA) or thermal reactive crosslinker melamine‐formaldehyde resin Cymel 303 clear considered. The main purpose of the investigation was to study the influence of diverse photoinitiators on main properties, such as shrinkage, tack, peel adhesion, and shear strength of solvent‐based acrylic pressure‐sensitive adhesives. The interesting alternative to conventional photoinitiators is unsaturated photoinitiators described in this article. Following unsaturated photoinitiators were used: 4‐acryloyloxy benzophenone, 4‐acryloyloxyethoxy benzophenone, and 4‐acryloyloxybutoxy benzophenone. The influence of the crosslinking agents or crosslinking methods was determined in relation to the reaction time and to the concentration versus adhesion properties. The increase of photoinitiator concentration causes in the decrease of the shrinkage. Increasing the UV dose during the crosslinking of acrylic PSA film leads clearly to better shrinkage resistance. The best results of the lowest shrinkage value of 0.35% were given by using 4‐acryloyloxy benzophenone. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011