Peel Test Using Nonstationary Peel Method

The cohesive peel spectra of pressure-sensitive adhesive (PSA) tapes have been measured using a non-stationary peel tester. The experimental evidence and a viscoelastic analysis based on a peel model indicate that there are no significant effects of acceleration in the normal rate region. The nonstationary peel tester can be regarded as a useful tool for testing and evaluating PSA tapes.     

Quantifying the Relationship Between Peel and Rheology for Pressure Sensitive Adhesives

An attempt is made in this work to model quantitatively the peel force vs. rate behavior of a pressure sensitive adhesive (PSA) tape. The approach follows suggestions of previous authors in modeling the deformation of the PSA as uniaxial extension of individual strands. A debonding failure criterion based on stored elastic energy density is used. In this work, experimental measurements of dynamic mechanical master curves are used to provide the mechanical properties of the PSA in the model. The predictions are compared with experimental peel force vs. rate master curves on tapes made from those same adhesives. The only adjustable parameter for the fitting is the quantity related to the debonding criterion. In this set of natural-rubber-based PSAs, the general shape of the peel master curve and the changes in peel behavior associated with tackifier loading and rubber molecular weight are well explained by the model. The effect of changes in substrate chemistry are not well explained.     

Effect of Peel Angle Upon Peel Force

Measurements of peel force P per unit width are reported for samples of three adhesive tapes, adhering to two different substrates. In all cases, the work of detachment per unit area of bonded interface was found to depend upon the angle θ of detachment, increasing as θ increases. This effect is attributed to dissipation of energy in bending the tape away from the substrate at the line of detachment, to a greater degree as θ increases. Extrapolation to θ = 0 is suggested as a simple way of minimizing contributions to the observed work of detachment that arise from bending an imperfectly-elastic adhering layer as it is peeled away from a flat rigid substrate. But at small peel angles the tape tends to stretch appreciably. Peeling at 45° is recommended to minimize both effects.     

Effect of Peel Angle Upon Peel Force

Measurements of peel force P per unit width are reported for samples of three adhesive tapes, adhering to two different substrates. In all cases, the work of detachment per unit area of bonded interface was found to depend upon the angle θ of detachment, increasing as θ increases. This effect is attributed to dissipation of energy in bending the tape away from the substrate at the line of detachment, to a greater degree as θ increases. Extrapolation to θ = 0 is suggested as a simple way of minimizing contributions to the observed work of detachment that arise from bending an imperfectly-elastic adhering layer as it is peeled away from a flat rigid substrate. But at small peel angles the tape tends to stretch appreciably. Peeling at 45° is recommended to minimize both effects.     

Synthesis of removable and repositionable water‐borne pressure‐sensitive adhesive acrylics

This publication shows the synthesis of the water‐borne removable pressure‐sensitive adhesive (PSA) based on acrylates and the influence of parameters such as internal emulsifiers on peel adhesion on steel and also the influence of N‐methylol acrylamide and plasticizers on peel adhesion on glass, poly(vinyl chloride), and polypropylene during aging time. Removable and repositionable pressure‐sensitive adhesives based on acrylic polymers are used for the production of removable memo notes, paper and foil labels, double‐sided tapes, carrier‐free tapes to protective films, and manufacturing aids. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 886–892, 2005     

电气胶带用有机硅压敏胶的研制

通过MQ硅树脂和端羟基聚二甲基硅氧烷(PDMS)的硅醇缩合反应制备有机硅压敏胶溶液,将合成的有机硅PSA压敏胶溶液涂布在基材上干燥后得到有机硅压敏胶胶带(PSA),研究了PSA的合成配料、工艺以及胶带生产工艺对压敏胶带性能的影响。结果表明,硅树脂/硅橡胶比例在1.2~1.4之间具有良好的初粘、持粘和剥离力,硅树脂含量增加胶带耐热性增强;此外,反应真空度低于0.07MPa,反应温度高于140℃,且添加2%~3%左右的BPO时所制备的PSA胶带具有良好的综合性能。     

Effect of Peel Load on Stringiness Phenomena and Peel Speed of Pressure-Sensitive Adhesive Tape

The factors governing interfacial separation in lightly cross-linked polymer adhesives at low pulling rates as demonstrated by their stringiness phenomenon are investigated.

Cohesive failure and adhesive/substrate interfacial separation of uncross-linked polymer adhesives have been adequately explained. However, in lightly cross-linked polymer adhesives, where cohesive failure cannot occur because there is no viscous flow, there are two regions of interfacial separation at low rate and this phemonenon cannot be readily explained by present viscoelastic theories.

Investigation of the stringiness phenomenon of peeling pressure-sensitive adhesive tapes at constant loads shows that two peeling speeds exist for any peeling load up to the vicinity of 200 g/25 mm. Also it is clear that stringiness structure differs greatly at each peeling speed. The stringiness phenomenon of each of these two regions is analyzed using Miyagi's observation apparatus. These two measurements are then reversed and a comparison shows that the two peeling speeds correspond to each steady peeling region.

This field of investigation, when added to the present viscoelastic property studies, should lead to a new peeling adhesive theory which, in turn, may lead to the development of new high peel force pressure-sensitive adhesives.     

马铃薯皮中多酚类物质的抗氧化性研究

通过体外抗氧化体系测定马铃薯皮多酚的抗氧化活性。除超氧阴离子的能力;马铃薯皮多酚清除羟基自由基的能力;马铃薯皮多酚清除DPPH自由基的能力;马铃薯皮多酚对油脂的抗氧化能力。马铃薯皮多酚对超氧阴离子的清除率最高达18.33%,且在低浓度清除能力明显高于同浓度抗坏血酸(Vc);马铃薯皮多酚对羟基自由基的清除率最高达92.26%。对DPPH自由基清除率最高达86.08%。油脂中添加马铃薯皮多酚提取液,可以明显降低油脂的过氧化值(POV)。马铃薯皮多酚对超氧阴离子,羟基自由基和DPPH自由基都有很好的清除效果,且在一定程度上降低油脂过氧化值随时间而延长的程度,是很好的天然抗氧化剂。     

Peel and shear strength of pressure‐sensitive adhesives prepared from epoxidized natural rubber

Peel and shear strength of two grades of epoxidized natural rubber (ENR 25 and ENR 50)‐based pressure‐sensitive adhesive was studied. Coumarone‐indene resin was used as the tackifier, whereas toluene was chosen as the solvent throughout the experiment. The tackifier loading was varied from 0 to 80 parts per hundred parts of rubber (phr). A SHEEN hand coater was used to coat the adhesive on substrate to give a coating thickness of 30, 60, 90, and 120 μm. Peel strength and shear strength of the adhesive were determined by using a Lloyd adhesion tester and Texture analyzer, respectively. Results show that maximum peel strength occurs at 40 phr of coumarone‐indene resin for both ENRs studied an observation, which is attributed to the maximum wettability of the substrate. However, the shear strength shows a gradual decrease with increasing tackifier loading because of the decrease in cohesive strength of adhesive. ENR 25 consistently indicates higher peel strength and shear strength than ENR 50. Generally, peel and shear strength increases with coating thickness. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007.     

Peel adhesion to paper—interpreting peel curves

Peel experiments involving three PSA tapes and three paper substrates were employed to develop a general approach for the analysis of peeling from paper. Plotting the logarithm of the peak peel force (i.e. the maximum value) versus the logarithm of the peel rate yielded a generalized peel curve which illustrated transitions from interfacial to paper failure. The general peel curve consisted of linear segments (on the log/log plots) which intersected when the failure mode changed from interfacial to paper failure. The influence of paper type, PSA type, and peel angle on the generalized peel curve was determined.     

Adhesive failure peak in peel spectra

Peel force spectra for pressure‐sensitive adhesive tapes provide a peel peak in the adhesive failure region. The observed peak behavior is coincident with calculation based on a viscoelastic peel model. It turns out that the origin of the peak is significantly associated with viscoelasticity or short relaxation time of the adhesive. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 264–266, 1999     

Novel acrylic pressure-sensitive adhesive (PSA) containing silver particles

Acrylic pressure-sensitive adhesives (PSAs) are generally considered as nonelectrically conductive materials. The electrical conductivity is incorporated into acrylic polymer after blending with electrical conductive additives like silver particles. After the addition of electrically conductive silver filler, the main and typical properties of PSAs such as tack, peel adhesion, and shear strength will decline. This study is the first trial which reveals that the acrylic self-adhesive basis must be synthesized with ameliorated initial performances like high tack and excellent adhesion. Currently, the electrically conductive solvent-borne acrylic PSA containing silver fillers are not commercially available on the market. They are promising materials which can be applied for the manufacturing of diverse technical or medical high performance self-adhesive products, such as broadest line of special electrically conductive sensitive tapes.     

微波辅助提取柚子皮中多糖的研究

讨论了利用微波辐射萃取法从柚子皮中提取多糖的不同因素的影响,通过实验确立了微波条件下提取多糖的最佳工艺条件为:浸提时间为4h,浸提温度为80℃,料液比为1︰50,浸提次数为4次,乙醇浓度为80%,微波辐射功率500W,辐射时间为5min,多糖提取率达到17.23%。     

微波辅助提取南瓜皮中果胶的研究

讨论了利用微波辐射萃取法从南瓜皮中提取果胶的不同因素的影响,通过实验确立了微波条件下提取果胶的最佳工艺条件为:用盐酸调pH值为1.8,用水作为溶剂,料液比为1∶20,微波辐射功率为600W,辐射时间为4min,乙醇(体积分数)为60%,提取率可达到16.9%。     

从柑橘皮中超声提取橙皮甙

在超声波作用下,用饱和Ca(OH)2水溶液浸提、盐酸酸析,从柑橘汁加工下脚料———柑橘果皮中提取橙皮甙。以精制橙皮甙收率为评价指标,利用正交实验L9(34)筛选最佳工艺条件为:超声提取温度25℃、超声时间30min、饱和Ca(OH)2溶液与柑橘皮质量比4∶1、超声频率25kHz。按优选的最佳工艺实验3次,精制橙皮甙平均收率达2 32%(为常规浸提法的1 61倍),相对标准偏差(RSD)为0 91%(n=3)。     

Protocols for the Measurement of Adhesive Fracture Toughness by Peel Tests

This article reports on the work of the European Structural Integrity Society Technical Committee 4 (ESIS TC4) and its activities in the development of test protocols for peel fracture. Thirteen laboratories have been working on peel test methods in ESIS TC4 since 1997 and their activities are ongoing.

The aim of the work is to develop robust and credible test methods for the determination of adhesive fracture toughness by peel tests. Several geometric configurations have been used, namely, multi-angle fixed arm peel, T-peel, and roller assisted peel in the form of a mandrel test.

The starting point of their work is an established analysis of a peel method that is often developed from a global energy approach. The adopted analysis is combined with an experimental approach in order to resolve ambiguities in the determination of adhesive fracture toughness (G_A). The test methods involve the measurement of peel strength in order to calculate the total input energy for peel (G) and the calculation of the plastic bending energy (G_P) during peel. The latter is often obtained from a measurement of the tensile behaviour of the peel arm. Adhesive fracture toughness is then G - G_P.

Four ESIS TC4 projects are described. The first relates to fixed arm peel whilst the second and third involve both fixed arm and T-peel. The fourth project combines mandrel peel and fixed arm peel. Each project uses different types of polymeric adhesives in the form of quite different laminate systems. The selection of the laminate system enables all characteristics of laminate property to be embraced, for example, thin and thick adhesive layers, polymeric, and metallic peel arms and a range of flexibility in the laminates.

The development of the enabling science required to establish the test protocols is described and software for conducting all calculations is referenced.     

桔皮中果胶的提取

报道了一种从桔皮中提取果胶的方法,探讨了酸度、温度、时间对收率的影响。     

Protocols for the Measurement of Adhesive Fracture Toughness by Peel Tests

This article reports on the work of the European Structural Integrity Society Technical Committee 4 (ESIS TC4) and its activities in the development of test protocols for peel fracture. Thirteen laboratories have been working on peel test methods in ESIS TC4 since 1997 and their activities are ongoing.

The aim of the work is to develop robust and credible test methods for the determination of adhesive fracture toughness by peel tests. Several geometric configurations have been used, namely, multi-angle fixed arm peel, T-peel, and roller assisted peel in the form of a mandrel test.

The starting point of their work is an established analysis of a peel method that is often developed from a global energy approach. The adopted analysis is combined with an experimental approach in order to resolve ambiguities in the determination of adhesive fracture toughness (G _A ). The test methods involve the measurement of peel strength in order to calculate the total input energy for peel (G) and the calculation of the plastic bending energy (G _P ) during peel. The latter is often obtained from a measurement of the tensile behaviour of the peel arm. Adhesive fracture toughness is then G – G _P .

Four ESIS TC4 projects are described. The first relates to fixed arm peel whilst the second and third involve both fixed arm and T-peel. The fourth project combines mandrel peel and fixed arm peel. Each project uses different types of polymeric adhesives in the form of quite different laminate systems. The selection of the laminate system enables all characteristics of laminate property to be embraced, for example, thin and thick adhesive layers, polymeric, and metallic peel arms and a range of flexibility in the laminates.

The development of the enabling science required to establish the test protocols is described and software for conducting all calculations is referenced.     

Peel strength improvement of foam core sandwich beams by epoxy resin impregnation on the foam surface

The interfacial adhesion characteristics between foam cores and faces affect much the structural integrity of foam core sandwich structures. The peel strength between the face plate and the foam core is one of the appropriate parameters for the interfacial characteristics of sandwich structures and its peel energy is also measured for the interfacial characterization. The peel strength is the first peak force per unit width of bondline required to produce progressive separation, and the peel energy is the amount of energy per unit bonding area associated with a crack opening. In this study, to improve the peel strength between the foam core and the face plate of foam core sandwich beams, the surfaces of foam core sandwich beams were resin-impregnated. Then the peel strength as well as peel energy of resin impregnated polyurethane foam core sandwich beams were measured by the cleavage peel test and compared with those of the same sandwich beams without surface resin impregnation on the foam surface.     

乘用车车身漆膜橘皮的成因及其预防

在乘用车的车身涂装中,涂层橘皮是最常见和难以控制的缺陷之一,已成为汽车厂家的棘手问题。阐述了影响涂膜流动和外观的因素;介绍了涂层外观漆膜橘皮的检测方法和车身漆膜橘皮的成因及其防治;以及乘用车塑料外饰件涂装受橘皮的影响因素及其控制;同时指出了车身漆膜橘皮的预防措施。