Loop Tack Research Articles

Toward replacement of methyl methacrylate by sustainable bio-based isobornyl methacrylate in latex pressure sensitive adhesive

Sustainable bio-based monomer isobornyl methacrylate (IBOMA) was evaluated as an alternative to traditional petroleum-based methyl methacrylate (MMA) as hard monomer in the application of acrylic latex pressure sensitive adhesive (PSA). The influence of bio-based IBOMA on the viscosity and particle size of the latexes and the gel content, sol molecular weight (Mw, Mn) and adhesive properties (loop tack, peel strength and shear strength) of the PSA copolymers were investigated. In addition, transmission electron microscopy (TEM), nuclear magnetic resonance (NMR), contact angle analysis, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA) were used to characterize the structure and properties of latexes and corresponding films. Results were compared with those obtained when using traditional petroleum-based hard monomer MMA. Some interesting phenomena and results were indeed obtained in this work. This article will not only enrich the application of bio-based monomer IBOMA in the field of acrylic emulsion PSA, but also provide sustainable methods for the preparation of high performance acrylic emulsion PSAs (e.g. high water resistance and high cohesion emulsion PSAs).

Synthesis and Properties of Water-Based Acrylic Adhesives with a Variable Ratio of 2-Ethylhexyl Acrylate and n-Butyl Acrylate for Application in Glass Bottle Labels.

A series of Pressure-Sensitive Adhesives (PSAs) with different soft monomer compositions were prepared by using emulsion polymerization. The monomers used were acrylic acid (AA), n-butyl acrylate (n-BA) and 2-ethylhexyl acrylate (2-EHA). Maintaining the same acrylic acid fraction in all polymerizations, the n-BA/2-EHA weight ratio varied from 0 to 1. These polymers were characterized by using Fourier Transformed Infrared Spectroscopy (FTIR), and the Glass Transition Temperature (Tg) was determined both theoretically from the Fox equation and experimentally by means of differential scanning calorimetry (DSC). The tetrahydrofuran (THF) insoluble polymer fraction was used to calculate the gel content, and the soluble part was used to determine the average molecular weight by means of Gas Permeation Chromatography (GPC). The adhesive performance was assessed by measuring tack, peel and shear resistance. The results showed that with the 2-EHA rate, the elastic modulus slightly decreased and the shear yield strength slightly increased. Consequently, the loop tack and peel resistances decreased. This behavior was attributed to the increase of the gel content with the ratio of comonomers studied. The adhesives were tested in paper labels on glass bottles immersed in a cold-water bath, the so-called ice bucket test, and all of them showed that they could withstand wet and cold environment conditions.

Effect of boron methacrylate monomer on the thermal and pressure-sensitive adhesive properties of 2-EHA-based copolymer latexes synthesized via mini-emulsion polymerization procedure

Pressure-sensitive adhesives (PSAs) are characterized by instantaneous adhesion upon application of light pressure. PSA performance is defined by peel strength, tack and shear strength. The adhesion and cohesion mechanisms are well defined as peel adhesion, loop tack and shear strength in the state of the art and can be adjusted according to the specific requirements. 2-Ethylhexyl acrylate-based latexes have been synthesized with the incorporation of boron methacrylate (BoMA) via mini-emulsion polymerization, and latexes with high surface area were obtained enabling interactive relation with polar and nonpolar surfaces. Cetyl alcohol was used as a cosurfactant to have colloidally stable hydrophobic particles in mini-emulsion polymerization. The incorporation of BoMA at 2% and 4% into the latexes led to an increase in peel adhesion strength on polar and nonpolar substrates. The addition of BoMA decreased the shear strength on both polar and nonpolar substrates at initial and after aging conditions. The shear strength was higher after the polymer films were aged providing a stable and stiff material. The amount of BoMA incisively affects the type of PSA and should be taken into consideration while constructing a polymer for a pre-specified application. The thermal properties were also improved by the addition of BoMA in terms of thermal stability and char yield. The assumptions in question were strongly correlated with peel, shear, loop tack values and thermal analysis.

Manipulation of chain transfer agent and cross-linker concentration to modify the performance of fluorinated acrylate latex pressure sensitive adhesive

n-Dodecyl mercaptan (DDM) chain transfer agent and 1,6-hexanediol diacrylate (HDDA) cross-linker were used to manipulate latex properties in a monomer-starved seeded semi-continuous emulsion polymerization of butyl acrylate (BA), fluorine monomer dodecafluoroheptyl methacrylate (DFMA) together with acrylic acid (AA) and 2-hydroxyethyl acrylate (HEA). The influences of both DDM and HDDA on the particle size of the latex, as well as on the gel content, thermostability (differential scanning calorimeter and thermal gravimetric analysis), surface properties (X-ray photoelectron spectra (XPS), contact angle analysis and atomic force microscopy), and viscoelasticity (N,N-dimethylacrylamide) of the polymer films were investigated. The results showed that the introduction of DDM and HDDA has no significant effects on the final particle size of the fluorinated pressure-sensitive adhesives (PSA) latexes. XPS analysis indicated that the fluoroalkyl groups had the tendency to enrich on the surface of the film. However, this enrichment of fluorine on the film surface was reduced after the introduction of HDDA, while increased with the addition of DDM. It was also found that the gel content, glass transition temperature (Tg), thermal stability, surface roughness, and modulus (G′, Gʺ) of the fluorinated latex PSA were all increased with the introduction of HDDA. Nevertheless, opposite trends were observed for the latex after the addition of DDM. Finally, the effects of DDM and HDDA on the adhesive properties (i.e. loop tack, peel strength and shear strength) of the fluorinated latex PSA were also evaluated.

Effect of the Crosslinking Agent Content on the Emulsion Polymerization Process and Adhesive Properties of Poly(N-Butyl Acrylate-Co-Methacrylic Acid)

A series of poly(n-butyl acrylate-co-methacrylic acid) with different contents of acrylic crosslinking agent (1,4-butanediol dimethacrylate, BDDA) latexes, named as poly(BA-co-MAA-co-BDDA), PBMABD, were synthesized via a two-stage sequential emulsion polymerization. During the polymerization, the particle sizes of the PBMABD latexes and conversions including instantaneous conversion and overall conversion of monomers were monitored online by dynamic light scattering (DLS) technology and gravimetric analysis in half-hour intervals, respectively. The overall conversions at the end of emulsion polymerization with different crosslinking agent contents were high, and the latex particles grew in a spherical shape without secondary particles during the growth process. The adhesive properties, including loop tack force, peel force and shear resistance, were evaluated systematically according to Fédération Internationale des Fabricants et Transformateurs d'Adhésifs et Thermocollants sur Papiers et Autres Supports (FINAT) test methods. When the content of the crosslinking agent was 0.5 wt%, a best equilibrium among the adhesive properties could be achieved. The adhesive properties of the PBMABD polymer were closely related to its viscoelastic behaviour and molecular structure, such as gel content and various molecular weight parameters.

Swelling effects on localized adhesion of an elastic ribbon.

We investigate the adhesion mechanism between an elastic strip of vinylpolysiloxane bent in a racquet-like shape, and a thick elastomeric substrate with the aim to understand how local swelling modifies adhesion. Using a modified loop-tack adhesion test, we place a droplet of silicone oil in between the two materials, vary the dwell time and measure the force required to separate the two interfaces. The experiments are then compared with an analytical model that describes how the critical peel force is modified as the interfacial surface energy changes over time. Our study reveals that in certain circumstances swelling can enhance adhesion. More specifically, strong adhesion is obtained when most of the droplet is absorbed by the solid. By contrast, when the droplet remains at the interface a small adhesive force is measured.

Incorporation of vinyl silane and epoxy silane oligomer into 2-EHA-based polyacrylate latexes via mini-emulsion polymerization and investigation of pressure-sensitive adhesive properties on polar and nonpolar surfaces

Pressure-sensitive adhesives (PSAs) form a bond to various surfaces when a light pressure is applied. PSAs combine the ability of being sticky with elasticity at definite proportions regarding the application area. The adhesion and cohesion mechanisms are well defined as peel adhesion, loop tack and shear strength in the literature and can be adjusted according to the specific requirements. On the purpose of having high peel adhesion and loop tack values without sacrificing the shear strength, 2-ethylhexyl acrylate-based latexes have been synthesized via mini-emulsion polymerization and latexes with high surface area were obtained enabling interactive relation with polar and nonpolar surfaces. Two types of silane selected among the mostly used species in industry were employed to increase the intermolecular interactions and proposed an approach for the incorporation of said compounds referring to the increasing demand of silane utilization in industry. N-dodecyl mercaptan was used as both chain regulator to adjust the molecular weight and cosurfactant to have colloidally stable hydrophobic particles in mini-emulsion polymerization. The incorporation of vinyl silane predominately led to an increase in shear strength owing to chemical cross-linking between chains. Epoxy silane oligomer, on the other hand, increased the peel adhesion and loop tack values considerably compared to the case of vinyl silane. The type of silane incisively affects the PSA properties and should be taken into consideration while constructing a polymer for a pre-specified application. The assumptions in question were strongly correlated with peel, shear and loop tack values, cross-linking density, molecular weight and gas chromatography measurements.

Thermoplastic polyurethane pressure sensitive adhesives made with mixtures of polypropylene glycols of different molecular weights

New more simple and easier strategy for synthesizing thermoplastic polyurethane pressure sensitive adhesives (TPU PSAs) has been proposed. Thus, the properties of the TPU PSAs were adjusted by fixing the NCO/OH ratio to 1.1 and varying the content of the hard segments by mixing high molecular weight and low molecular weight polyether polyols during TPU synthesis. The thermoplastic polyurethanes have been synthesized with methylene diisocyanate (MDI), 1,4 butanediol chain extender and different mixtures of two polypropylene glycols (PPGs) polyols with different molecular weights (450 and 2000 Da). TPUs with different hard segments content (12.5–38.7%) were synthesized and their pressure sensitive adhesive properties depended on their hard segments contents and degree of phase separation. In general, the TPU PSAs with higher hard segments content exhibited low probe tack and low loop tack regardless of the nature of the metallic and polymeric substrate. In contrast, the 180° peel strength depended noticeably on the nature of the polymeric substrate and on the hard segments content of the TPU. TPU PSAs with hard segments content lower than 20.9% were general purpose or removable PSAs and the ones with higher hard segments content were high shear PSAs.

In Situ Semibatch Emulsion Polymerization of 2‐Ethyl Hexyl Acrylate/n‐Butyl Acrylate/Methyl Methacrylate/Cellulose Nanocrystal Nanocomposites for Adhesive Applications

AbstractCellulose nanocrystals (CNCs) are safe, “green,” hydrophilic nanoparticles. CNCs are added in situ during a semibatch 2‐ethyl hexyl acrylate (EHA)/n‐butyl acrylate (BA)/methyl methacrylate (MMA) emulsion polymerization. As EHA is a more hydrophobic monomer, manipulation of the monomer feed composition allows for the evaluation of the effect of hydrophobicity on CNC distribution in the nanocomposite and ultimately on adhesive properties. The adhesive properties (loop tack, peel strength, and shear strength) of three different EHA/BA/MMA latex formulations are shown to simultaneously improve with increasing CNC loading. However, the hydrophobicity of the EHA leads to a nonuniform distribution of CNCs in the latex films. Comparison of the in situ polymerized nanocomposites to their blended counterparts is also made.

Enhanced Mechanical and Adhesion Properties in Sustainable Triblock Copolymers via Non-covalent Interactions

ABA triblock copolymers are used as thermoplastic elastomers (TPEs) for a wide variety of applications. Herein, we describe incorporation of sugar-based glassy components to create sustainable triblock copolymers as alternatives for commodity TPEs. Poly(glucose-6-acrylate-1,2,3,4-tetraacetate) [PGATA] and poly(acetylated acrylic isosorbide) [PAAI] end blocks were chain-extended from a poly(n-butyl acrylate) [PnBA] midblock. PAAI–PnBA–PAAI exhibited excellent adhesion properties: peel = 8.74 N cm–1, loop tack = 2.96 N cm–2, no shear failure up to 100 h, and shear adhesion failure temperature (SAFT) = 60 °C. Although similar peel adhesion and higher loop tack were observed for PGATA–PnBA–PGATA, the shear strength and SAFT were moderate (18 h and 42 °C, respectively). PAAI–PnBA–PAAI are tough elastomers and demonstrated high stress and elongation at break (σ = 6.5 MPa and e = 620%, respectively) while the GATA-based analogue exhibited weaker tensile properties (σ = 0.8 MPa and e = 476%). To address this, the...

Transdermal Delivery of Ibuprofen Utilizing a Novel Solvent-Free Pressure-sensitive Adhesive (PSA): TEPI\xae Technology

PurposeThe main objective of this present study was the investigation of potential novel transdermal patch technology (TEPI®) delivering ibuprofen as the active pharmaceutical ingredient (API) using a novel poly(ether-urethane)-silicone crosslinked pressure-sensitive adhesive (PSA) as the drug reservoir in a solvent-free manufacturing process.MethodsThe patch was synthesized utilizing the hot-melt crosslinking technique without the addition of solvents at 80 °C in 100% relative humidity. Dissolution and permeation studies performed utilizing diffusion cells and subsequently HPLC validated methods were employed to determine the API content in the acceptor solution. Accelerated stability studies were also performed at 40 °C and 70% relative humidity. The adhesive performance of the fabricated patch was evaluated utilizing loop tack adhesion tests.ResultsIn vitro permeation experiments across both Strat-M® and human skin demonstrated that ibuprofen can easily be released from the adhesive matrix and penetrate through the studied membrane. A comparison on the permeation rates of the API across the two membranes indicated that there is not a strong correlation between the obtained data. The presence of chemical enhancers facilitated an increased flux of the API higher than observed in the basic formulation. Initial stability studies of the optimized formulation showed no degradation with respect to the drug content. Adhesion studies were also performed indicating higher values when compared with commercially available products.ConclusionsThe present study demonstrated the fabrication of an ibuprofen patch utilizing a versatile, solvent-free drug delivery platform. Upon optimization of the final system, the resulting patch offers many advantages compared to commercially available formulations including high drug loading (up to 25 wt%), good adhesion, and painless removal leaving no residues on the skin. This PSA offers many advantages over existing adhesive technology.Graphical ᅟ

Atomic force microscopy investigation of phase morphology correlated with adhesive properties for modified telechelic natural rubber based-pressure sensitive adhesive

Atomic force microscopy (AFM) is a powerful technique to determine phase morphology and surface mechanical properties of materials. In this research natural rubber was degraded and grafted by malelic anhydride before modification with 3-amino-1,2,4-triazole to obtain modified telechelic natural rubber or modified TNR. It was then blended with cumarone-indene resin at 10, 30, and 50 phr, acting as tackifier. Phase morphology and surface topography were investigated by intermitted AFM. The results showed that tackifier enriched domains were clearly observed in modified TNR matrix after added 30 and 50 phr and the domain sizes were approximately to be the order of micrometer (5–10 µm) which it increased with increasing tackifier content. The intermolecular hydrogen bonding interaction between tackifier and modified TNR was observed by attenuated total reflectance Fourier transform infrared spectroscopy. The adhesive properties (loop tack, peel, and shear strength) were governed by the size of tackifier enriched domains, surface mean roughness and compatibility or interaction between modified TNR rubber and cumarone-indene tackifier resin.

Synthesis of poly(BA-co-MMA) dispersions having AA/MAA/AAm/MAAm comonomers and the comparison of their effect on adhesive performance

Pressure-sensitive adhesives (PSAs) bond to surfaces by applying a light pressure, and must be soft and tacky which requires the glass transition temperature (T g) below −20 °C. Performance characterization is done via adhesion and cohesion. Achievement of high adhesion and high cohesion together is a challenge for PSA applications. In this study, a series of PSAs with different monomer compositions were prepared using emulsion polymerization to show the effect of polar comonomers on adhesive properties. The main monomer was butyl acrylate and methyl methacrylate, and the polar comonomer was chosen from acrylic acid (AA), methacrylic acid (MAA), acrylamide (AAm), and methacrylamide (MAAm). The adhesive performance was studied at 0.5, 1.25, and 2% of the polar comonomer content based on total monomer composition. Water-borne acrylic adhesive polymers obtained with constant thickness were coated onto a bi-oriented polypropylene and evaluated for the effect on performance by measuring their loop tack, peel, and shear strength on several surfaces, including stainless steel, glass, aluminum, and low-density polyethylene (LDPE). Results showed that MAAm increases cohesive forces compared to AAm due to dipole–dipole interactions. When the amount of polar comonomer with T g above room temperature has been decreased, there have been a significant increase on the adhesion properties and tackiness of the polymers beside on LDPE due to its non-polar surface characteristics. When AA and MAA compared, there have been a significant increase on cohesive strength on all the surfaces. The highest adhesion has been obtained using AA in a lower amount. The adhesion and cohesion balances were better achieved with 0.5% s/m MAAm and 2.5% s/m AA, respectively. This study does not only show the effect of polar monomers on adhesion and cohesion properties, but also show the adhesive and cohesive effects of hydrogen bonding on different surfaces.

Power feed synthesis of pressure-sensitive latex adhesives

Latex particles with the same core composition of poly(MMA-co-ALMA) and different shell compositions of poly(BA-co-AA) were prepared by semibatch emulsion polymerization using ‘power feed’ monomer and chain transfer agent addition methods in the shell layers. The seed stage involved formation of seed particles of 111 nm in diameter with a batch process. After that, two growth stages formed the final particle diameter, dz = 300 nm measured by dynamic light scattering. The gel content and the molecular parameters of the polymer were determined. The adhesive properties including loop tack, peel force and shear resistance were measured according to the FINAT test methods No. 9, 1 and 8. An evaluation was also made for the relationship between pressure-sensitive properties and molecular parameters. Introducing power feed to semibatch emulsion polymerization had no significant effect on the latex preparations and could improve the final conversion and the colloidal stability. The observed particles were grown without significant secondary nucleation. The power feed methods had no effect on the glass transfer temperature (Tg) of the shell layer also. Emulsion polymerization conducted by positive power feed resulted in the formation of longer primary polymer chains at the beginning than that conducted by negative power feed and standard uniform feed, which caused a very high gel fraction. As pressure-sensitive adhesives prepared by using the positive power feed had the highest gel content and strongest core–shell interaction, they exhibited the highest shear resistance, but the lowest tack and peel force.

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 (Mc) and sol molecular weight (Mw, Mn) 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.

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 (Tg) 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 (Mw, Mn) 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 4wt%, and the maximum value appeared at 1wt%. Peel strength reduced, while shear strength improved with increased DMA concentration.

Effect of Magnesium Oxide Loading on Adhesion Properties of ENR 25/NBR Blend Adhesives in the Presence of Petro Resin and Gum Rosin Tackifiers

The adhesion properties of magnesium oxide filled epoxidized natural rubber (ENR 25)/acrylonitrile-butadiene rubber (NBR) blend adhesives were studied using petro resin and gum rosin as tackifiers. Toluene was used as the solvent throughout the experiment. Five different loadings, i.e. 10, 20, 30, 40 and 50 phr magnesium oxide was used in the adhesive formulation. The SHEEN hand coater was used to coat the adhesive on polyethylene terephthalate at 30 and 120 µm coating thickness. The tack, peel strength and shear strength were determined by a Lloyd adhesion tester operating at 30 cm min−1. Results shows that all the adhesion properties of the ENR 25/NBR adhesives show a maximum value at 10 phr filler loading. Loop tack and peel strength pass through a maximum, an observation which is associated to the optimum wettability of adhesive on the substrate. For the shear test, maximum shear strength occurs due to the optimum cohesive strength of the adhesive. Results also show that all petro resin based adhesives have higher adhesion properties than gum rosin based adhesive. In all cases, the adhesion properties of adhesives also increase with increasing coating thickness.

Acrylic Triblock Copolymers Incorporating Isosorbide for Pressure Sensitive Adhesives

A new monomer acetylated acrylic isosorbide (AAI) was prepared in two steps using common reagents without the need for column chromatography. Free radical polymerization of AAI afforded poly(acetylated acrylic isosorbide) (PAAI), which exhibited a glass transition temperature (Tg) = 95 °C and good thermal stability (Td, 5% weight loss; N2 = 331 °C, air = 291 °C). A series of ABA triblock copolymers with either poly(n-butyl acrylate) (PnBA) or poly(2-ethylhexyl acrylate) (PEHA) as the low Tg midblocks and PAAI as the high Tg end blocks were prepared using Reversible Addition–Fragmentation chain Transfer (RAFT) polymerization. The triblock copolymers ranging from 8–24 wt % PAAI were evaluated as pressure sensitive adhesives by 180° peel, loop tack, and static shear testing. While the PAAI-PEHA-PAAI series exhibited poor adhesive qualities, the PAAI-PnBA-PAAI series of triblock copolymers demonstrated peel forces up to 2.9 N cm–1, tack forces up to 3.2 N cm–1, and no shear failure up to 10 000 min. Dynamic m...

Properties of single-component acrylic pressure-sensitive adhesives synthesized using tert-butyl peroxypivalate initiator

In this work, tert-butyl peroxypivalate initiator was newly used in the solution polymerization of acrylic copolymers with 2-ethylhexyl acrylate, butyl acrylate, methyl methacrylate and acrylic acid monomers for application of pressure-sensitive adhesives (PSAs). Its proper dosage was determined to vary from 0.6 to 1.2 wt % when a high monomer conversion (>99%) was ensured. In this amount range, polymer properties and adhesive performance of the PSAs were investigated. The results indicated that with the amount of tert-butyl peroxypivalate increased, the molecular weights of the polymer decreased and the molecular weight distribution became wider. It was also observed that the synthesized PSAs had high interfacial adhesion and low cohesion strength, and thus exhibited cohesive failure during the peel test. So cross-linking agent was employed to improve the shear strength of the PSAs and to eliminate the adhesive residue while at the sacrifice of loop tack and peel strength. As a whole, the optimal performance was obtained by using 1.2 wt % amount of initiator and 0.5 wt % concentration of cross-linker. In this case, the peel and shear strength have achieved the best balance. In addition, for the cross-linked PSA tapes, the peel strength slightly decreased with the dwell time.

Adhesion property of crosslinked epoxidized (natural rubber)/(acrylonitrile‐butadiene) rubber blend adhesives in the presence of petro resin tackifier

Loop tack, peel strength, shear strength, and morphology of (benzoyl peroxide)‐cured epoxidized natural rubber (ENR 25)/(acrylonitrile‐butadiene) rubber (NBR) blend adhesive were investigated by using petro resin as the tackifying resin. Benzoyl peroxide loading varied from 1 to 5 parts by weight per hundred parts of resin (phr), whereas the petro resin loading was fixed at 40 phr. A SHEEN hand coater was used to coat the adhesive on the polyethylene terephthalate substrate at 30 μm and 120 μm coating thicknesses. (ENR 25)/NBR adhesive was crosslinked at 80°C for 30 min prior to the determination of adhesion strength by a Lloyd adhesion tester operating at 10–60 cm/min. Results show that maximum loop tack and peel strength occur at 2 phr of benzoyl peroxide loading, whereby optimum cohesive and adhesive strength are obtained. However, shear strength increases with increasing benzoyl peroxide concentration, an observation that is associated with the steady increase in the cohesive strength. Scanning electron microscopy micrograph shows that little adhesive remained on the substrate at 0 phr compared with 2 phr of benzoyl peroxide loading, indicating that crosslinking increases the peel strength of the adhesive. In all cases, the adhesion properties increase with coating thickness and testing rate. J.VINYL ADDIT. TECHNOL., 24:93–98, 2018. © 2015 Society of Plastics Engineers