双组份固化型保护膜体系的研究

本文研究了各种因素对双组份保护压敏胶膜性能的影响，包括压敏胶的配方设计，交联剂品种及用量；溶剂选择及用量，以及上述诸因素之间的关系。     

表面保护膜用丙烯酸乳液压敏胶的合成及性能研究

以丙烯酸(AA)、丙烯酸丁酯(BA)、丙烯酸异辛酯(EHA)、丙烯酸羟乙酯(HEA)和醋酸乙烯(VAM)为共聚单体,采用预乳化半连续乳液聚合法制备用于保护膜的压敏胶乳液。讨论了BA/EHA质量比、乳化剂用量、引发剂用量、交联剂的用量和反应温度对丙烯酸乳液压敏胶的固含量、初黏性和180°剥离强度的影响。研究结果表明,丙烯酸乳液压敏胶适宜的反应条件为:BA/EHA质量比为45∶45,引发剂用量为0.15%(wt)~0.2%(wt),乳化剂用量为0.8%(wt)~1.0%(wt),交联剂用量为0.1%(wt)~0.3%(wt),反应温度为82~85℃。     

环保型低剥离力压敏胶的研制

采用半连续乳液聚合法制备了一种丙烯酸类水基型低剥离力压敏胶。主要考察了甲基丙烯酸(MAA)等功能单体和外加交联剂对产物性能的影响。实验表明,随MAA等亲水单体用量的增多,乳液粘度会增大,而引入交联单体在实验范围内可显著降低剥离强度。功能单体用量有一合适范围。选用较高反应活性的氨基树脂作交联剂,可改善耐温性,保持初粘力,得到综合性能较好的低剥离力压敏胶。     

丙烯酸酯单体烷基长度对LCD压敏胶性能的影响

采用共聚的方法制得了不同性质的丙烯酸酯共聚物,进一步制备了适用于LCD偏光片的压敏胶,探讨了不同烷基数的丙烯酸单体对及烘干工艺对压敏胶性能的影响。得到初粘力,剥离强度较佳的偏光片用丙烯酸酯压敏胶体系。     

压敏保护膜及其在现代工业中的应用

对压敏保护膜的原理、构成、制造方法以及在现代工业中的应用进行了研究分析。     

水性聚氨酯压敏胶的制备与性能研究

以聚丙二醇(N-220)和异佛尔酮二异氰酸酯(IPDI)为主要原料、二羟甲基丙酸(DMPA)和聚乙二醇(PEG)为亲水性物质、三乙胺为中和剂,制备出一种具有压敏特性的水性聚氨酯(WPU)胶粘剂。通过红外光谱(FT-IR)法、粒度分析法等检测手段,研究了DMPA、PEG、中和剂、增黏树脂和交联剂等对WPU的结构和性能的影响。结果表明:亲水性基团含量越少,产物粒径越大,耐水性越好;中和度越低,WPU胶膜的耐水性越好,同时可供交联的羧基含量越多;当中和度为33.3%、w(固化剂)=1.5%时,WPU压敏胶带的内聚强度较大且不脱胶,其吸水率为31.2%,180°剥离强度为2.2N/25mm,可望在保护膜胶带等领域中得到应用。     

The Effects of Viscoelasticity in the Peeling of Polymeric Films

A method to compute the interfacial fracture energy of a polymer film bonded to a rigid substrate, using the measured quantities of a peel test, is presented. The formulation is general and will accept any polymer which can be modeled as a linear viscoelastic material. The method is used to analyze the peeling of a polyimide film and a relationship between the fracture energy, the peel force, the speed of peeling and the thickness of the film is derived.     

The Contact Adhesion of Self-Adhesive Strain Gauges

Thin pieces of flexible polymers may be adhered to rigid substrates merely by pressing the two surfaces into intimate contact. The peel strength of the bond is poor, but the shear strength can be sufficiently high for strain gauge operation. This paper offers an explanation for the adhesion which can account quantitatively for the behaviour of various materials. Frictional phenomena, resulting from a normal force produced by the surface tension of a surface film, can explain why a gauge with a PVC body does not slip. With other polymers, other liquids or electrostatic effects may be of importance. Any surface “fluid” film of sufficiently high viscosity that viscous effects are important will behave as an integral part of the elastomer.     

Peeling of Acrylic Pressure Sensitive Adhesives: Cross-Linked versus Uncross-Linked Adhesives

In this paper we analyze the adhesive properties of two kinds of adhesives, determined by a 90[ddot] peeling test on a Pyrex^TM substrate. Simultaneously, we observe the mechanisms of flow at the peeling front. An uncross-linked acrylic pressure-sensitive adhesive is used, whereas the second one, of the same class, is slightly cross-linked. The mechanisms of peeling are compared with the ones of our previous study (Benyahia et al [8]) and are found to be identical in the case of uncross-linked adhesives. On the other hand, we find new regimes of flow when the adhesive is cross-linked.

To investigate these differences further, we determine the rheometrical properties of the adhesives in dynamic shear tests and in uniaxial elongational experiments. Furthermore, surfaces are characterized.

A discussion of the peeling curves is finally presented, showing the combined effects of the rheological properties and the surface ones. Conditions for predicting the type of regimes and transitions are also investigated.     

Sawtooth-shaped stringiness with front frame formation for polyacrylic pressure-sensitive adhesives with two different molecular structures

The formation of sawtooth-shaped stringiness during 90° peeling was investigated using crosslinked poly(n-butyl acrylate–acrylic acid) and poly(2-ethylhexyl acrylate–acrylic acid) random copolymers with an acrylic acid content of 5 wt.% and different crosslinking degrees as pressure-sensitive adhesives (PSAs). The gel fraction was measured by toluene extraction of PSA, and it increased with crosslinker content for both systems. The observed stringiness was sawtooth-shaped, but there were three different types; both the typical sawtooth shape and the frame formed at the front tip with interfacial failure, and the sawtooth shape formed with cohesive failure. The change in the stringiness shape was affected strongly by the gel fraction of PSA. The peel rate under constant peel load was measured and revealed that the peel rate was lowest upon formation of the front frame type. A good relation was found between peel rate and peel strength, with a greater peel strength upon formation of the front frame type. The concentrated stress at the peeling tip is released by progress of peeling and deformation of the adhesive layer (stringiness) for no frame type. On the other hand, the sufficient interfacial adhesion delays the progress of peeling, and the applied larger stress causes cavitation in the PSA layer for front frame type. The formed cavity grows and the front frame type formed as a result. That is, internal deformation occurred preferentially over peeling. In order to improve the peel strength, the front frame type is the most useful stringiness shape.     

米黄色压敏胶带生产中常见的问题

本文介绍了米黄色双向拉伸聚丙烯压敏胶带生产中常见的问题,揭示了问题产生的原因,提出了解决问题的方法。     

保护膜用丙烯酸酯乳液压敏胶的研制

选用反应性乳化剂,采用预乳化半连续聚合方法,合成出了综合性能良好的保护膜用丙烯酸酯乳液压敏胶。探讨了单体组成、乳化剂和引发剂用量对压敏胶初黏力、180°剥离强度、180°剥离强度增幅及耐高温高湿老化性能的影响。结果表明:当2-EHA/BA为8/2～6/4,MMA/VAc为6/4～4/6,MAA为3份,乳化剂和引发剂用量分别为单体用量的0.75%和0.5%时,压敏胶综合性能良好,适用于PVC型材表面保护膜的制造。     

聚氨酯压敏胶的合成与性能研究

以4,4’-二环己基甲烷二异氰酸酯(HMDI)为异氰酸酯硬段、聚醚二元醇(DL-2000)为软段、三羟甲基丙烷(TMP)为扩链剂,通过溶液聚合法制备溶剂型聚氨酯压敏胶A组分。以氨基树脂为交联剂、强酸为催化剂,在120℃条件下烘烤1 min进行交联固化,得到聚乙烯(PE)保护膜。研究表明:当交联剂用量为A组分用量的12%~20%时,制备的PE保护膜性能良好,保护膜与基材之间反复粘结剥离无残胶。     

Two dimensional analysis for an adhesively bonded composite single-lap joint based on flexible interface theory

An improved two-dimensional model based on flexible interface theory is proposed for an adhesively bonded composite single-lap joint. In the modified model, the adherends are treated as a Timoshenko beam, and the adhesive layer is assumed to be an Euler–Bernoulli beam. The peel stress and shear stress across the adhesive thickness varied. Additionally, the zero shear stress condition at the free end of the adhesive layer was satisfied. Based on the displacement compatibility condition of a flexible interface, the governing differential equations for the internal forces are derived. The stress distributions of the adhesive layer can be obtained by solving the governing differential equations. A comparison of the results between the modified model, existing classical models, and finite element results indicate that the improved two-dimensional model can determine the stress distribution of the adhesive with high accuracy. Finally, the effects of the thickness ratio, Young’s modulus ratio, and interfacial compliance on the stress distribution of the adhesive are studied using the improved model.     

光学透明胶膜CEF0807的性能研究

光学透明胶膜(CEF0807)是一种用于粘接光学透明元件的特种PSA(压敏胶),其对被粘基材的力学性能、透光性能、雾度、色彩失真度和可靠性等影响很大。研究结果表明:CEF0807是一种粘接性能优异的压敏胶,其对玻璃、聚碳酸酯(PC)、聚甲基丙烯酸甲酯(PMMA)和聚对苯二甲酸乙二醇酯(PET)等基材的180°剥离强度分别为141、117、108、103 N/100 mm;CEF0807具有优异的光学性能,其透光率为94.3%,而雾度和色差(ΔE)仅分别为0.80%和1.48;CEF0807经环境可靠性测试后性能优异,非常适合于光学元件、光学视窗等材料的粘接。     

交联型聚丙烯酸酯压敏胶乳液的合成及其粘接性能的研究

利用功能单体的自交联作用,采用种子半连续乳液聚合的方法进行多元共聚,合成了兼具较高剪切强度和剥离强度的交联型聚丙烯酸酯压敏胶乳液。运用DSC、DMA及粘接性能测试分别考察了聚合物的玻璃化转变温度、动态力学性能和压敏胶粘性能,并分析讨论了三者之间的相互关系。结果表明:功能单体所产生适度交联作用能较好地协调聚合物的内聚力和粘合力之间的平衡,使其具有较好的粘接及力学性能。聚合物的Tg、粘弹性等物理参数可用于评估其内聚力及粘接强度。     

乳液型丙烯酸酯医用压敏胶的研制

介绍了乳液型丙烯酸酯医用压敏胶的合成方法,研究了各种因素对胶粘剂性能的影响。对溶剂型和乳液型丙烯酸酯医用压敏胶的性能进行了比较。     

功能性压敏胶与压敏制品的应用

本文介绍了新的功能性压敏胶及赋于新功能压敏制品。     

表面保护胶带用聚丙烯酸酯乳液压敏胶的研究

用半连续预乳化种子乳液聚合法合成了保护膜用乳液压敏胶,主要研究了底相种子乳液中乳化剂的用量、多官能度氮丙啶类交联剂的用量对乳液压敏胶性能的影响。研究结果表明:随着种子乳液中乳化剂用量的增加,乳胶粒的粒径减小,乳液粘度、表面张力和接触角增加;增加交联剂的用量可显著提高乳液压敏胶的耐老化性能;同温度相比,湿度对乳液压敏胶的耐老化性能影响更加显著;被保护材料表面的极性和光洁度对压敏胶的耐老化性能亦有显著影响。