Effect of propyleneimine external cross-linker on the properties of acrylate latex pressure sensitive adhesives

Acrylate pressure sensitive adhesive (PSA) latexes were synthesized via a starved monomer seeded semi-batch emulsion polymerization process with butyl acrylate (BA), methyl methacrylate (MMA), acrylic acid (AA) and 2-hydroxyethyl acrylate (HEA). These PSA polymers were then cross-linked with trifunctional propyleneimine external cross-linker (SAC-100) to study the cross-linking reaction between carboxylic group of the polymer chain and cross-linking agent. It was found that cross-linking provided a significant influence on the film formation process based on the result of SEM analysis. In addition, with the increase of SAC-100 content, the gel content of the polymer increased significantly, while molecular weight between cross-link points (M_c) and the sol molecular weight (M_w, M_n) of the polymer decreased remarkably. The TGA result showed that the addition of the external cross-linker can enhance the thermal stability of the latex film. Moreover, for the cross-linked adhesive film, the shear strength was improved greatly while at the sacrifice of loop tack and peel strength, when compared with the uncross-linked counterparts. Besides, dynamic mechanical analysis (DMA) was also used to evaluate the viscoelastic properties of the acrylate emulsion PSA film.     

乳液型丙烯酸酯压敏胶的研制

采用乳液聚合制备了乳液型聚丙烯酸酯压敏胶,讨论了软单体的用量、硬单体用量、交联单体的种类及用量、引发剂的用量、交联剂的用量和乳化剂的配比对压敏胶性能的影响。实验表明,在相同的条件下,丙烯酸的改性效果比丙烯酸羟乙酯好,当m（EHA）∶m（VAc）=82∶10时,压敏胶的综合性能最佳。交联剂的加入明显提高了剥离强度,当其质量分数为0.3%时,剥离强度达到357.33 N/m。     

Effect of N,N-dimethylacrylamide (DMA) on the comprehensive properties of acrylic latex pressure sensitive adhesives

Acrylic pressure sensitive adhesive (PSA) latexes were synthesized via a monomer-starved seeded semi-continuous emulsion polymerization process with butyl acrylate (BA), methyl methacrylate (MMA), N,N-dimethylacrylamide (DMA), acrylic acid (AA) and 2-hydroxyethyl acrylate (HEA) as monomers. Impacts of DMA on the resultant latex and PSA properties were comprehensively investigated. Results indicated that latex particle size was independent of the amount of DMA in the pre-emulsion feed with excessive and constant surfactant concentration. Latex viscosity increased with DMA concentration. It was also found that water resistance of acrylic latex PSA became worse by the presence of DMA, confirmed by water contact angle measurements. Besides, DSC results showed that as the amount of DMA increased, glass transition temperatures (T_g) of the polymers were elevated significantly. TGA results showed that thermal stability of PSA was improved with DMA as a co-monomer. Furthermore, as DMA amount increased, gel content slightly increased, while sol molecular weight (M_w, M_n) of the polymer decreased. Finally, with respect to the adhesive properties of the PSA, it was observed that loop tack initially increased and then decreased with the addition of DMA from 0 to 4 wt%, and the maximum value appeared at 1 wt%. Peel strength reduced, while shear strength improved with increased DMA concentration.     

Improving the properties of water-borne pressure sensitive adhesives by using non-migratory surfactants

The adhesive performance of high solids content water-borne acrylic pressure sensitive adhesives synthesized using polymerizable surfactants (Latemul^®PD-104 and Sipomer^®Pam-200) or a polymerizable stabilizer (Sipomer^®Cops-1) has been studied. The use of a high pH during the polymerization process has a deleterious effect on the final adhesive properties because gel polymer is not formed. Interestingly, at low pH it is found that the surfactant concentration used during the polymerization process has also an effect on the polymer microstructure; the higher the surfactant concentration, the higher the final gel content of the latex. When polymerizable surfactants or a stabilizer are used the peel strength of the final films is considerably improved due to the surfactant incorporation into the polymer backbone and hence reduced surfactant migration to the air-film interface. Work of adhesion and shear adhesion failure temperature (SAFT) are not noticeably affected by surfactant migration but their performance is affected by the surfactant employed.     

丙烯酸酯乳液压敏胶合成及其常规性能研究

采用半连续种子乳液聚合法制得纯丙乳液压敏胶。研究了胶粘剂厚度、基材厚度、基材类型对压敏胶常规力学性能影响。结果发现,各因素对压敏胶的初粘性和剥离强度影响较大;基材厚度及类型对持粘性影响较小;胶层厚度为15μm左右的压敏胶具有较高性价比。     

丙烯酸酯乳液压敏胶的研制

对乳液聚合法制备丙烯酸酯压敏胶的工艺进行了探讨。实验表明:共聚物的组成,乳化剂的种类及用量,反应温度,反应时间,引发剂用量,搅拌速度对压敏胶的性能有较大影响。     

Preparation and characterization of self-crosslinking fluorinated polyacrylate latexes and their pressure sensitive adhesive applications

Self-crosslinking fluorinated polyacrylate latexes based on butyl acrylate (BA), fluorine monomer octafluoropentyl methacrylate (OFPMA), self-crosslinking functional monomers acrylic acid (AA) and 2-hydroxyethyl acrylate (HEA) were synthesized by a monomer-starved seeded semi-continuous emulsion polymerization process. The latexes and their corresponding films were characterized by laser particle size analyser, Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), contact angle goniometer, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Results indicated that the particle size of the latexes and the gel content of the films were both independent of the amount of OFPMA employed. On the other hand, the particle size of the latexes decreased and the gel content of the films increased with the incorporation of AA and HEA as expected. Glass transition temperature (T_g) and the thermal stability of the copolymer were both improved gradually as OFPMA content increased. XPS, AFM and water contact angle measurement indicated that the fluoroalkyl groups had a tendency to enrich on the surface of the films. However, this enrichment of fluorine on the film surface was reduced after the introduction of self-crosslinking functional monomers into the system. Finally, the adhesive property of the latexes was evaluated for application as a pressure sensitive adhesive (PSA).     

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。     

乳液型丙烯酸酯压敏胶粘剂剥离强度的研究

应用正交设计探讨了丙烯酸酯压敏胶粘剂的优化配方，考察了温度、反应时间和单体的滴加速度对共聚反应的影响，并分别用一定量的甲基丙烯酸甲酯、丙三醇和松香对胶粘剂进行了初步改性研究。     

溶剂型丙烯酸酯压敏胶的研制

以甲基丙烯酸甲酯(MMA)和醋酸乙烯酯(VAc)为硬单体、丙烯酸(AA)和丙烯酸羟乙酯(HEA)为交联单体、甲苯-2,4-二异氰酸酯(TDI)为交联剂和偶氮二异丁腈(AIBN)为引发剂,采用溶液聚合法制取溶剂型聚丙烯酸酯压敏胶(PSA),讨论了硬单体和交联单体的种类及用量、引发剂和交联剂的用量以及烘胶温度对PSA性能的影响。实验结果表明,当W(AA)=3%、W(VAc)=17%时,初粘力为13号球,剥离强度达到14.17N/15mm,PSA的综合性能最佳;当W(TDI)=1.2%时,剥离强度(17.26N/15mm)达到最大值;当W(AIBN)=0.5%时,胶液的黏度适中,综合性能最佳。     

溶剂型聚丙烯酸酯类压敏胶的研制

采用溶液聚合制备了溶剂型聚丙烯酸酯类压敏胶．讨论了改性单体的种类及用量、链转移剂的用量、引发剂的加入方式、聚合反应温度、胶液黏度和烘胶温度对压敏胶粘接性能的影响。实验表明,丙烯酸可以全面提高压敏胶的粘接性能,引发剂的加入方式能够有效调节聚合产物分子质量,链转移剂可以维持聚合反应的稳定性,适当的胶液黏度和烘胶温度将有利于提高压敏胶的粘接性能。     

有机硅压敏胶粘剂的研究概况

介绍了有机硅压敏胶的性能特点及应用；综述了该胶种在国内外的研究开发的历史及现状，展望了有机硅压敏胶的发展前景。     

丙烯酸酯压敏胶的研究进展

概述了近年来各种丙烯酸酯类PSA(压敏胶)的研究进展,重点介绍了乳液型、溶剂型、热熔型和辐射固化型丙烯酸酯类PSA的制备工艺及应用性能。最后对丙烯酸酯类PSA的发展方向进行了展望。     

New green surfactants for emulsion polymerization

Nonylphenol ethoxylates (NPEOs) are widely used as surfactants for emulsion polymerization and for post adding stabilization for latex applications in formulations with high filler content. However, the current exposure situation of NPEOs in Europe gives rise to environmental concern, despite of the fact that some industry associations have already pro-actively taken measures to phase out these chemistry of their products, e.g. the European detergent industry (AISE) by a voluntary commitment. As a consequence, the EU Commission has recommended to implement a risk reduction strategy, which foresees the ban of all applications leading to direct emissions to waste water and strict emission controls for all other technical processes using NPEOs as surfactant. The effectiveness of the risk reduction measures will be monitored by the authorities. In case that the environmental concentrations of NPEOs and their metabolites do not decrease by at least 70 percent, additional risk reduction measures for technical applications are planned. In one of the major fields of application, alkyl phenol-free emulsifiers with a more favorable ecological profile are becoming key ingredients for eco-friendly emulsion polymers and polymer dispersions: the Disponil^® AFX-Series (Cognis) is a NPEO-free surfactant system for emulsion polymerization and polymer dispersant also as a supposition for getting the European eco-label for indoor paints and varnishes.

These new non-ionic surfactant system exhibits an effective performance during polymerization and as post reaction stabilizers. These products are environmentally compatible, mostly derived from natural renewable resources and readily biodegradable. The underlying chemistry is in compliance with relevant indirect food contact applications [BfR recommendations, respectively, FDA CFR 21 (federal drug administration)], and a dossier to register the surfactants in the positive list of the EU Directive 2002/72/EC for application in plastic has recently been submitted.

Clear, high solid liquids at room temperature, these surfactants are easy to handle and very effective with regard to controlling particle size, film properties and overall latex stability. This paper summarizes their chemical and surface properties, as well as their performance in model emulsion polymerization formulations for architectural coatings.     

Effect of trifunctional cross-linker triallyl isocyanurate (TAIC) on the surface morphology and viscoelasticity of the acrylic emulsion pressure-sensitive adhesives

Acrylic pressure sensitive adhesive (PSA) latexes were synthesized via a starved monomer-seeded semi-continuous emulsion polymerization process with butyl acrylate (BA), methyl methacrylate, acrylic acid (AA), 2-hydroxyethyl acrylate and trifunctional cross-linker, triallyl isocyanurate (TAIC). Influences of TAIC on the resultant latex and PSA properties were comprehensively investigated. The results indicated that latex particle size was independent of the amount of TAIC in the pre-emulsion feed, while the viscosity of the latex increased remarkably with TAIC content increased. Thermal gravimetric analysis result showed that the thermal stability of the polymers was improved significantly with the addition of TAIC. Besides, with the increase in TAIC content, gel content of the polymer increased significantly, while molecular weight between cross link points (M_c) and sol molecular weight (M_w, M_n) of the polymer decreased remarkably. Moreover, for the cross-linked adhesive film, the shear strength was improved greatly while at the sacrifice of loop tack and peel strength, when compared with the uncrosslinked counterparts. Finally, dynamic mechanical analysis and atomic force microscopy were also used to evaluate the viscoelastic properties and surface morphology of the acrylic emulsion PSA film, respectively.     

我国压敏胶粘带工业的现在与未来

介绍了我国压敏胶粘带工业及与之相关的原材料和设备等工业的现状；分析了制约我国胶粘带产业发展的因素，对我国压敏胶粘带产业发展的品种和方向提出观点。     

有机硅胶粘剂的研究进展

综述了有机硅胶粘剂的组成、种类、性能及其应用。并对硅橡胶胶粘剂在粘接性、导热性、固化性能的研究进展进行了叙述。     

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     

Solventless UV crosslinkable acrylic pressure sensitive adhesives

The synthesis and characterization of solventless acrylic UV crosslinkable pressure sensitive adhesives are presented. Different prepolymers were synthesized using bulk polymerization procedure. The reaction mixture consisted of acrylic monomers (2-ethylhexyl acrylate, acrylic acid and t-butyl acrylate), azobisisobutyronitrile initiator, chain transfer agent n-dodecylmercaptan and unsaturated UV photoinitiator 4-acryloyloxybezophenone, which was copolymerized into polymer backbone. Different formulations were tested and the prepolymer was characterized by viscosity measurements and final monomer conversions. The prepolymers were coated onto PET foil and crosslinked by application of UV light source. Peel adhesion at 180° on glass plate was measured. Gel phase was determined using the Soxhlet extraction and copolymer glass transition temperatures (T_g) were analyzed by differential scanning calorimetry (DSC). Results showed that the final monomer conversions in highly exothermic bulk polymerization reached a level between 75% and 90%. Prepolymer viscosity was highly influenced by change in polymer molecular weight and by addition of acrylic acid as a comonomer. On the other hand, the viscosity remained at the low level when t-butyl acrylate was used. The amount of gel phase for all adhesives was above 60 wt.%. Peel strength measurements showed decrease in peel strength with decreasing polymer molecular weight and increase of peel, when acrylic acid was used as a comonomer. All adhesive coatings with t-butyl acrylate comonomer showed cohesive failure.     

丙烯酸酯乳液胶粘剂的研究及应用

综述了近年来我国丙烯酸酯乳液胶粘剂的最新研究现状,并介绍了丙烯酸酯乳液胶粘剂在压敏胶及包装材料中的应用,指出了我国丙烯酸酯乳液胶粘剂的发展方向。