Pressure-sensitive Adhesive Tape Research Articles

Insects did it first: a micropatterned adhesive tape for robotic applications

Based on the structural and experimental studies of more than 300 insect species from different lineages, we have developed and characterized a bioinspired polymer material with the ability of multiple glue-free bonding and debonding. The material surface is covered with a pattern of microstructures, which resembles the geometry of tenent hairs previously described from the feet of flies, beetles, earwigs and other insects. The tape with such a microstructure pattern demonstrates at least two times higher pull-off force per unit apparent contact area compared to the flat polymer. Additionally, the tape is less sensitive to contamination by dust particles than a commercially available pressure-sensitive adhesive tape. Even if the ‘insect tape’ is contaminated, it can be washed with a soap solution in water, in order to completely recover its adhesive properties. We have successfully applied the tape to the 120 g wall-climbing robot Mini-Whegs™. Furthermore, the tape can be used for multiple adhering of objects to glass surfaces or as a protective tape for sensitive glass surfaces of optical quality. Another area of potential applications is gripping and manipulation of objects with smooth surfaces.

Peel of an adhesive tape from a temperature-gradient surface

The peel force of a pressure sensitive adhesive (PSA) tape is measured on a surface that varied linearly in temperature. As the tape is peeled from the surface, the adhesive is peeled from the surface at a different temperature. Since the peel force varies with temperature, the measurement allows the temperature dependence of the peel force to be determined with one peel test. By this method, the temperature of the transition from cohesive to interfacial failure can be easily identified, not only by the relative peak in the peel force, but also by the clearly visible adhesive layer that remains on the stainless steel plate during cohesive failure. Peel forces are measured at 90° and 180° peel angles and peel rates between 0.05 and 15 mm/s. The peel forces measured on a temperature-gradient surface are similar in magnitude to peel forces measured on the same surface but at constant temperature and averaged over longer peel lengths.

Examination of Writings Concealed by Black Pressure Sensitive Adhesive Tape

Examination of concealed writing is often a challenge for forensic document examiners. Although the published literature describes many techniques, these are often only successful when the writing has been concealed by pencil, pen, or by spreading inks of different tint or by smearing of the writing with colored fluids. When black pressure sensitive adhesive (PSA) tape is used, these procedures are ineffective. The present report describes the use of a straight chain hydrocarbon to remove the PSA tape and allow a comparison of the concealed writing with that of a suspect. The use of the solvent had no observable effect on either the writing or the substrate. The procedure is rapid and easy to use and is also effective with other colored PSA tapes.

Development of solvent-free acrylic pressure-sensitive adhesives

The present publication describes a problem to develop solvent-free acrylic pressure-sensitive adhesives (PSA). Solvent-free PSA are established materials for the manufacturing of various self-adhesive products. Only by means of these acrylic PSA was it possible to succeed in drafting the present surprisingly efficient generation of double-sided pressure-sensitive adhesive tapes, medical products, protective masking films, films for the graphics market, and various specialty products. New applications and technical specifications stimulate the continuous development of new methods of polymerization of solvent-free acrylates. New syntheses of solvent-free acrylic PSA include polymerization in the reactor with removal of the solvent and polymerization on the carrier. The polymerization process is connected with UV-crosslinking.

Properties of pressure‐sensitive adhesive tapes with soft adhesives to human skin and their mechanism

The use of soft adhesives in the manufacture of pressure-sensitive adhesive tapes has recently increased. The dermal peeling force of adhesive tapes with soft adhesives was studied. Four kinds of adhesive tapes with adhesives of different softness were made, by adding varying amounts of isopropyl myristate as a softener. The tapes were applied on the flexor side of the forearm of six healthy male volunteers. The dermal peeling force, the amount of stripped corneocytes, the level of pain when the tapes were removed and the degree of penetration of adhesives into the sulcus cutis (skin furrows) were evaluated at 1 and 24 h after application of the tapes. Furthermore, a skin model panel (a sulcus cutis and crista cutis model panel) and a crista cutis model panel were constructed from a general stainless-steel panel, and the peeling force of the tapes against the model panels was measured. As the softness of adhesives increased, the peeling force against a general stainless-steel panel with a flat surface decreased, although the peeling force against human skin did not significantly change. The amount of stripped corneocytes on the removed tapes and the level of pain when the tapes were removed decreased with the increase in softness of the adhesives. These results suggest that adhesive tapes with soft adhesives that contain isopropyl myristate as a softener are suitable for the skin. Furthermore, the degree of penetration of adhesive into the sulcus cutis increased as the softness of adhesives increased. Upon evaluation of the peeling force against the model panels, as the softness of adhesives increased, there was a slight decrease in the peeling force against the skin model panel, while there was a remarkable decrease in the peeling force against the crista cutis model panel. These results suggest that the lack of change in the dermal peeling force as the softness of adhesives increased was caused by penetration of soft adhesive into the sulcus cutis, and that the decrease in the amount of stripped corneocytes was caused by a decrease in the peeling force against the crista cutis, which consists of corneocytes mainly removed by the tapes.

Fundamentals of hot-melt pressure-sensitive adhesive tapes: the effect of tackifier aromaticity

We revisit the effect of varying the tackifier aromaticity on adhesive performance in a styrenic block co-polymer (SBC)-based pressure-sensitive adhesive tape. Aromaticity strongly affects the compatibility between the tackifying resin and base polymer and is defined as the relative number of protons attached to an aromatic ring. Dynamic mechanical analysis, peel resistance, tack, shear resistance and atomic force microscopy were utilized to detect changes in adhesive performance due to resin aromaticity. The results indicate that increasing the aromaticity of the tackifier enhanced the compatibility between the tackifier and styrene domains. As a consequence, the high-temperature cohesive performance measured by the shear adhesion failure temperature decreased due to plasticization of the end-blocks by the aromatic resins. However, other properties of interest such as the glass transition of the rubbery matrix, tack, peel resistance and holding power were less affected by the resin aromaticity. We note that this paper is of limited scope because we have focused this research on styrene–isoprene–styrene, which is very compatible with a wide range of tackifiers. More significant differences would be expected in formulations based on styrene–butadiene–styrene or styrene–isoprene–butadiene–styrene polymers in which the compatibility between the resin and midblock would be more sensitive to the resin aromaticity. In addition to our results, we review the literature and some fundamentals of formulating SBC-based adhesives and PSA testing.

Deposition of hexafluoropropene by atmospheric pressure glow plasma on an elastic polymer: Application to release coating on pressure-sensitive adhesive tapes

Plasma-polymerized hexafluoropropene (PPHFP) film had adhesive strength that was low enough for use as a release coating, but a small amount of PPHFP peeled off from a poly(ethylene terephthalate) (PET) film substrate. The insertion of a soft and elastic polymer, polyethylene glycol, between the two layers prevented the PPHFP peeling off from PET. The results also showed that the polymerization degree of PPHFP was low.

碁盤目テープはく離試験の粘着テープに関する因子の再検討

碁盤目テープはく離試験の粘着テープに関する因子の再検討

Interfacial Diffusion of Fluids in Pressure Sensitive Adhesives

Abstract Diffusion of acetone at the interface of a bonded pressure sensitive adhesive tape was measured using single frequency capacitance measurements (SFCM) and a novel interdigitated electrode sensor design. The relative concentration of acetone at the bondline as a function of distance from the edge of the specimen and exposure time was correlated to adhesion loss measured by the 90° peel test. This work suggests that these novel sensors are applicable for the study of interfacial diffusion processes, and could be extended to other coatings or adhesives in a variety of environments.

Influence of Experimental Setup and Plastic Deformation on the Shaft-Loaded Blister Test

ABSTRACT In the shaft-loaded blister test (SLBT), plastic deformation often occurs at the contact area between the shaft tip and adhesive layer, leading to a larger displacement (blister height) than if the film was loaded elastically. As a consequence, incorporating the displacement variable into the analysis can result in misleading values of the applied strain energy-release rate, 𝒢. In this work, the influence of plastic yielding at the contact area on 𝒢 of a thin film was investigated as a function of some common SLBT experimental variables, namely, substrate hole diameter, film thickness, and shaft-tip diameter. Test specimens consisted of plies of pressure-sensitive adhesive tape adhered to a rigid glass substrate. 𝒢 was calculated from the following Equations: (1) load-based, (2) hybrid, (3) displacement-based, and (4) combination. Decreasing the film thickness, increasing the hole diameter, or decreasing the shaft-tip diameter lead to more plastic yielding at the contact area as well as to an increase in blister height. The increased blister height resulting from plastic deformation leads to disagreement among the values of 𝒢 calculated from the different Equations when the displacement variable was included in the calculation. However, the load-based equation, which does not include the displacement, was determined to be independent of plastic yielding and the “correct” equation for calculating 𝒢. In addition, the film tensile rigidity (Eh) was calculated using an experimental compliance calibration. The effects of film thickness on the mechanical behavior of the film (bending plate vs. stretching membrane) as well as methods to determine the displacement resulting from plastic deformation are also discussed.

Skin irritation due to repetitive application of adhesive tape: the influence of adhesive strength and seasonal variability

Influence of the repetitive application of pressure-sensitive adhesive tapes on skin was evaluated. Two kinds of tapes with different adhesive strengths were repetitively applied to the inside of the forearm of six volunteers in winter and summer, in order to examine the dermal peeling force, the amount of stripped corneocytes, transepidermal water loss (TEWL), hydration and deepened skin furrows (changes in skin surface topography) in the epidermal stratum corneum. As adhesive tapes were applied repetitively, dermal peeling force gradually increased while the amount of stripped corneocytes decreased. As the cumulative amount of stripped corneocytes increased with repetitive applications, the skin irritation worsened as measured by increased destruction of the skin surface topography and TEWL. These phenomena were more marked with the stronger adhesive tape, and there was seasonal variability.

Pyrolysis-Gas Chromatography/Mass Spectrometry of Acrylic Adhesives of Cloth and Kraft Adhesive Tapes

The adhesives of seventeen acrylic pressure sensitive cloth adhesive tapes and seventeen kraft adhesive tapes were analyzed by pyrolysis-gas chromatography/mass spectrometry(Py-GC/MS) at 500°C. The main pyrolysates were butyl acrylate (BA), 2-ethylhexyl acrylate(2EHA), ethyl acrylate(EA), methyl methacrylate(MMA), tolylenediisocyanate(TDI) and the pyrolysates of an aromatic petroleum resin(C9 Resin). The acrylic adhesives were classified into twelve groups according to their pyrolysates.

Relation between phase structure and peel adhesion of poly(styrene-isoprene-styrene) triblock copolymer/tackifier blend system

The effect of tackifier on the adhesive properties of a model pressure-sensitive adhesive tape was investigated. For this purpose, a model system consisting of poly(styrene-isoprene-styrene) triblock copolymer as the base polymer and a typical aliphatic petroleum resin as the tackifier was prepared. The tackifier content ranged from 10 to 60 wt%. The tackifier used has a good compatibility with polyisoprene, whereas it has a poor compatibility with polystyrene. The 180° peel adhesion was measured. The peel adhesion increased with the tackifier content, while the degree of increase became more significant above 40 wt%. The pressure sensitivity appeared obviously and the maximum peel adhesion was obtained without heating above 40 wt%. The phase structure was determined using pulse 1H-NMR, transmission electron microscopy and dynamic mechanical analysis. A phase structure in which spherical polystyrene domains with a mean size of about 20 nm were dispersed in the polyisoprene continuous phase was observed. It was found that the tackifier-rich phase of the order of nanometers in size was formed in the polyisoprene matrix and the concentration increased with the tackifier content. The tackifier-rich phase seemed to develop the cohesive strength and, thus, it increased the peel adhesion.

Reliability of Pressure-Sensitive Adhesive Tapes for Heat Sink Attachment in Air-Cooled Electronic Assemblies

This study investigates the reliability of commercially available pressure-sensitive adhesive (PSA) tapes used for electronic component-to-heat sink attachment. It is found that creep can affect the PSA reliability. Therefore, creep is experimentally characterized using isothermal, constant load, double lap shear measurements in conditions representative of vertically oriented heat sink applications. PSA joint life predictions are derived from the accelerated creep characteristics using a secondary creep model. The creep resistance of a laminated silicone/aluminum/acrylic PSA tape is found to be significantly lower than that of a single-layer acrylic tape. This suggests that the potential impact of tape creep on joint reliability should be carefully evaluated as a function of tape chemistry/construction and application environment. Furthermore, the sensitivity of PSA creep characteristics to both operating temperature and heat sink weight highlights the need for thermally optimized, least-weight heat sink designs.

A Spectral Identity Mapper for Chemical Image Analysis

Generating chemically relevant image contrast from spectral image data requires multivariate processing algorithms that can categorize spectra according to shape. Conventional chemometric techniques like inverse least squares, classical least squares, multiple linear regression, principle component regression, and multivariate curve resolution are effective for predicting the chemical composition of samples having known constituents, but they are less effective when a priori information about the sample is unavailable. We have developed a multivariate technique called spectral identity mapping (SIM) that reduces the dependence of spectral image analysis on training datasets. The qualitative SIM method provides enhanced spectral shape specificity and improved chemical image contrast. We present SIM results of spectral image data acquired from polymer-coated paper substrates used in the manufacture of pressure sensitive adhesive tapes. In addition, we compare the SIM results to results from spectral angle mapping (SAM) and cosine correlation analysis (CCA), two closely related techniques.

Modeling of the Peeling Process of Pressure-sensitive Adhesive Tapes with the Combination of Maxwell Elements

A simple model for the peeling process of pressure-sensitive adhesive tape is presented. The model consists of linear springs and dashpots and can be solved analytically. Based on the modeling, the curved profile of the peeling tape is spontaneously determined in terms of viscoelastic properties of adhesives. Using this model, two experimental results are discussed: critical peel rates in the peel force and the peel rate dependence of the detachment process of adhesive from the substrate.

Forensic isotope ratio mass spectrometry of packaging tapes

Pressure sensitive adhesive tape (brown parcel tape) is employed in a great many criminal activities such as the restraint of individuals during robbery and offences against the person, the enclosure of explosive devices and the packaging and concealment of controlled drugs. Packaging materials are ubiquitous in modern society and are produced in such vast quantities that it is increasingly difficult to distinguish between different products or to link materials to a common source. This study demonstrates the potential of stable isotope ratio mass spectrometry to characterise parcel tapes based on a number of properties. The carbon isotopic signature, derived from the substrate polymer, associated additives and adhesive is highly characteristic of a particular tape and allows samples from different sources to be readily distinguished. Further discrimination may be achieved by the incorporation of deuterium and oxygen isotopic data and by analysis of the isolated backing polymer. Recovery of intact tape from simulated forensic samples proved straightforward and the isotopic signature of the tape did not appear to be affected by adverse storage conditions.

Measurement of the loss tangent of a thin polymeric film using the atomic force microscope

An atomic force microscope was used to measure the loss tangent, tan δ, of a pressure-sensitive adhesive transfer tape as a function of frequency (0.01 to 10 Hz). For the measurement, the sample was oscillated normal to the surface and the response of the cantilever resting on the polymer surface (as measured via the photodiode) was monitored. Both oscillation amplitude and phase were recorded as a function of frequency. The atomic force microscopy measurement gave the same frequency dependence of tan δ as that measured by a dynamic shear rheometer on a film 20 times thicker. The results demonstrate that the atomic force microscope technique can quantitatively measure rheological properties of soft thin polymeric films.

Evaluation of pressure-sensitive tape adhesion and backing directionality by excimer laser methods

The effects of 248 nm KrF excimer laser irradiation on a pressure-sensitive adhesive tape bonded to a glass substrate were investigated as a possible method to evaluate the quality of adhesion, as well as the directionality induced during manufacture. The model pressure-sensitive tape consisted of biaxially-oriented polypropylene (PP) tape coated with a hot-melt rubber resin. Analysis of the front-shot experiments, which were performed by irradiation through the PP backing, allowed correlation between the excimer laser irradiation-induced detachment and the peel adhesion strength. For this purpose, peel tests were performed before and after laser shots. The directionality induced during manufacture resulted in a more ablated area in the strength direction than in the transverse direction when the bonded tapes were irradiated with an elliptically-shaped laser beam above the ablation threshold. A correlation was found between the detachment bubbles created by irradiation below the ablation threshold and their respective peel adhesion values, which allows us to evaluate the quality of adhesion for pressure-sensitive tapes. Thus, a method to evaluate the quality of adhesion using an excimer laser is proposed based on the findings of this work.

Bond strength of pressure sensitive adhesives for CFRP aluminium-alloy hybrid beams under impact loading

This paper discusses the impact absorbing capabilities of CFRP aluminium-alloy hybrid beams bonded with double-coated pressure sensitive adhesive tapes. Two sons of double-coated adhesive tapes (VHB and SBT, 3M) were used in experiments. The strength and absorbed energy of the beams under impact loading were measured using an instrumented Charpy tester. Using the beams having the different adhesive tapes and the CFRP of different length, the variations of the strength and the absorbed energy were investigated. The beams bonded with VHB showed sufficient strength and absorbed energy. SBT showed also great capability of absorbing impact energy.