Acrylic Pressure-sensitive Adhesives Research Articles

Viscoelastic and adhesive properties of single‐component thermo‐resistant acrylic pressure sensitive adhesives

ABSTRACTPoly(butyl acrylate‐vinyl acetate‐acrylic acid) based acrylic pressure sensitive adhesives (PSAs) were synthesized by solution polymerization for the fabrication of high performance pressure sensitive adhesive tapes. The synthesized PSAs have high shear strength and can be peeled off substrate without residues on the substrate at temperature up to 150°C. The PSAs synthesized in the present work are single‐component crosslinked and they can be used directly once synthesized, which is convenient for real applications compared to commercial multi‐component adhesives. The results demonstrated that the viscosity of the PSAs remained stable during prolonged storage. The effects of the preparation conditions such as initiator concentration, cross‐linker amount, organosiloxane monomer amount and tackifier resin on the polymer properties, such as glass transition temperature (Tg), molecular weight (Mw), surface energy and shear modulus, were studied, and the dependence of the adhesive properties on the polymer properties were also investigated. Crosslinking reactions showed a great improvement in the shear strength at high temperature. The addition of tackifier resin made peel strength increase compared to original PSAs because of the improvement of the adhesion strength. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40086.

Optical properties and adhesion performance of acrylic PSAs; influence of functionalized monomer and curing agent

Acrylic pressure–sensitive adhesives (PSAs) were synthesized by solution polymerization using zirconium carboxyethyl acrylate (ZrCEA) with methyl aziridine derivatives (MAZ) as a curing agent. The acrylic PSAs were characterized by Fourier transform-infrared spectroscopy and gel contents. The viscoelastic properties of the acrylic PSAs were determined using an advanced rheometric expansion system. The adhesion performance of the acrylic PSAs was determined by measuring the probe tack, peel strength, shear adhesion failure temperature, and holding power. The optical properties of the acrylic PSAs were evaluated by the transmittance and refractive index. The results show that the adhesion performance and optical properties of the acrylic PSAs are influenced by the ZrCEA and MAZ content.

Photocrosslinking of solvent-based acrylic pressure-sensitive adhesives (PSA) by the use of selected photoinitiators type I

This study investigated the photocrosslinking of solvent-based acrylic pressure-sensitive adhesives (PSA) containing selected photoinitiators type I, known as α-cleavage photoinitiators. Photocrosslinking of PSA, especially of acrylic PSA, is well established crosslinking process using the UV radiation technology. UV-initiated crosslinking of acrylic PSA allows the synthesis of the wide range of UV-crosslinkable PSA with the interesting features. Especially, the important balances of properties such as adhesive and cohesive strength which are typically critical for the application performance can be achieved by this technology. The selection of suitable photoinitiator plays an important role to obtain the optimum properties of acrylic PSA including tack, peel adhesion, and shear strength. In this study, the investigations on different saturated conventional photoinitiators of type I for solvent-based PSA were carried out. The effects of photoinitiator concentration, UV crosslinking time and UV dose on the tack, peel strength, and shear strength were explored in detail for guiding the choice of photoinitiators to fabricate advanced PSA for industrial usage.

Effect of permeation enhancers on dynamic mechanical properties of acrylate pressure sensitive adhesives

Physico-chemical properties of permeation enhancers like molecular weight/size, hydrophobicity/hydrophilicity, co-solvency, etc. are necessary during their selection for pharmaceutical product development. Chemical permeation enhancers modulate the viscoelastic properties of pressure sensitive adhesives. The extent of this modulation depends upon the molecular size and branching of the polymeric chains. The functional nature of this branching additionally changes the peel and tack properties of PSA's. Chemical permeation enhancers alone are not able to modify viscoelastic properties of aqueous based PSA's as compared with their solvent based counterparts. These modulated mechanical aspects need to be maintained throughout development of transdermal patch along with other pharmaceutical aspects like drug release and drug stability.

Fabrication of optically clear acrylic pressure–sensitive adhesive by photo-polymerization: UV-curing behavior, adhesion performance, and optical properties

Acrylic pressure–sensitive adhesives (PSAs) with 2-phenoxy ethyl acrylate (PEA) were polymerized using UV-curing technology. This study examined the effects of PEA content and UV dose. The photo-polymerization behavior of the pre-polymer was examined by viscosity measurements, real-time Fourier transform infrared spectroscopy, and photo-differential scanning calorimetry. The curing behaviors of the acrylic PSAs were investigated by shrinkage test, a modular advanced rheometer system, and gel content. differential scanning calorimetry and Advanced Rheometric Expansion System were used to characterize the acrylic PSAs. Adhesion performances were measured by probe tack, peel strength, and shear adhesion failure temperature. The optical properties of acrylic PSAs were examined by UV–visible spectroscopy and prism coupler. The PEA content had a larger effect on improving the optical properties, than did the UV dose. The transmittances of the acrylic PSAs with <75% PEA were >95%. The refractive indices of the acrylic PSAs increased with increasing PEA content, due to its high refractive index, >1.5, which affected the overall refractive indices, particularly in the visible region.

Optical properties and adhesion performance of optically clear acrylic pressure sensitive adhesives using chelate metal acetylacetonate

Optically clear acrylic pressure-sensitive adhesives (PSAs) with different co-monomers were synthesized. This study employed metal chelate aluminum acetylacetonate and zirconium acetylacetonate as curing agents. The optical properties of the acrylic PSAs were examined by UV–visible spectroscopy and a prism coupler. In addition, the adhesion performance was obtained by assessing the peel strength, the tack, and the shear adhesion failure temperature. The decrease in the adhesion performance may be related to a higher crosslinking density, which also resulted in a higher gel content.

Kinetic and characterization of UV-curable silicone urethane methacrylate in semi-IPN-structured acrylic PSAs

To improve the thermal stability of general acrylic pressure-sensitive adhesives (PSAs), polydimethylsiloxane (PDMS) was used and UV curing was employed. Silicone urethane methacrylate (SiUMA) was synthesized and introduced into acrylic PSAs for a semi-interpenetrating polymer network structure. The structure of the SiUMA was investigated through C NMR, H NMR, and FT-IR. The kinetics and behaviors of SiUMA (S1) were found by adding photoinitiators (PI) of 0.5, 1.0, 5.0, and 10 phr in a binder, which were examined using the photo-DSC (pDSC). After setting PI as 5.0 phr in a binder and UV intensity as 1000 mJ/cm2, the SiUMA, which was prepared by a radical polymerization, was added to acrylic PSA to 20, 40, 60, and 80% composition, and its kinetics and behaviors were analyzed by pDSC. Finally, the peel strength was checked to evaluate adhesion performance of the acrylic PSAs. The reaction rate was increased with increasing amounts of S1 and PI. Peel strength was dropped sharply with increasing crosslinking density.

Preparation and properties of UV curable acrylic PSA by vinyl bonded graphene oxide

Acrylic pressure sensitive adhesives (PSAs) with higher thermal stability for thin wafer handling were successfully prepared by forming composite with the graphene oxide (GO) nanoparticles modified to have vinyl groups via subsequent reaction with isophorone diisocyanate and 2-hydroxyethyl methacrylate. The acrylic copolymer was synthesized as a base resin for PSAs by solution radical polymerization of ethyl acrylate, 2-ethylhexyl acrylate, and acrylic acid followed by further modification with GMA to have the vinyl groups available for UV curing. The peel strength of PSA decreased with the increase of gel content which was dependent on both modified GO content and UV dose. Thermal stability of UV-cured PSA was improved noticeably with increasing the modified GO content mainly due to the strong and extensive interfacial bonding formed between the acrylic copolymer matrix and GO fillers

Manufacturing of Solvent-Free Acrylic Pressure-Sensitive Adhesives in Form of Self-Adhesive Layers

The present publication is related to a process for producing the non-solvent acrylic pressure-sensitive adhesive (PSA). New applications and technical specifications stimulate the continuous development of new methods of polymerization of solvent-free acrylate. New synthesis of solvent-free acrylics includes polymerization in the reactor with removal of the solvent and polymerization of the carrier. The polymerization process is connected with UV-crosslinking.

Copolymerizable Photoinitiators Based on Benzophenones and their Influence on Shrinkage of Photoreactive Acrylic PSAs

This manuscript describes a novel class of copolymerizable benzophenone photoinitiators and their influence on viscosity and molecular mass of acrylic pressure-sensitive adhesives (PSAs) during radical solvent polymerization and shrinkage of acrylic PSAs coated on PVC film and crosslinked using UV radiation.

New Copolymerizable Photoinitiators for Radiation Curing of Acrylic PSA

This article presents a new class of copolymerizable photoinitiators containing vinyloxycarbonyl groups, known such as organic carbonate or carbamate. Novel copolymerizable photoinitiators have been prepared through the reaction between vinyl chloroformate and hydroxyl groups containing photoreactive derivatives such as benzophenone-, acetophenone-, benzoine-and anthrachinone-derivatives. The main emphasis is given to the influence of this new class of unsaturated photoinitiators on UV-crosslinking process of acrylic pressure-sensitive adhesives (PSA). Moreover, the paper describes the influence of various parameters such as UV-initiated crosslinking time and concentration of unsaturated photoinitiators on relevant PSA properties like tack, peel adhesion and shear strength (cohesion).

UV-Crosslinkable Photoreactive Pressure-Sensitive Adhesives Synthesized from Butyl Acrylate and 4-Acryloyloxy Benzophenone

The manuscript describes synthesized of photoreactive UV-crosslinkable solvent-borne acrylic pressure-sensitive adhesives (PSA) based on butyl acrylate (BA) and copolymerizable photoinitiator 4-acryloyloxy benzophenone (ABP) characterized by molecular mass in the range of 180 000 to 480 000 Dalton. These copolymers were tacky but possessed insufficient cohesive strength after UV-crosslinking to be useful as PSA. They resulted in materials having a balance of cohesive and adhesive characteristics required of good PSA. Some of the parameters affecting the pressure-sensitive adhesive properties of the copolymer are: amount of the 4-acryloyloxy benzophenone, molecular mass of the polymeric components, UV-reactivity and such important properties like tack, peel adhesion and shear strength.

How does the surface free energy influence the tack of acrylic pressure-sensitive adhesives (PSAs)?

This article describes a comparative study of the tack properties of a model acrylic pressure-sensitive adhesive (PSA) crosslinked using aluminum acetylacetonate on several substrates, including stainless steel, glass, polyethylene, polypropylene, polytetrafluoroethylene, polycarbonate, and poly(methyl methacrylate). The tack measurements were conducted using a technique commonly used to measure the tack of an adhesive tape in the PSA industries. The surface free energy (SFE) values of the materials were evaluated using the Owens–Wendt and van Oss–Chaudhury–Good methods. The experiments showed a clear relationship between the SFE of the substrate and the tack of the model acrylic PSA. In general, larger differences between the SFE values of the substrate and adhesive (ΔSFE) were correlated with greater tack values. The tack of the model acrylic PSA was found to be optimal over the ΔSFE range of 7.0–13.1 mJ/m2. The trend in the tack as a function of the SFE difference was attributed to the quantity of energy dissipated at the jointed points during the separation stage in the loop tack test.

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.

Manufacturing of Solvent-Free Acrylic Pressure-Sensitive Adhesives in Form of Self-Adhesive Layers

The present publication is related to a process for producing the non-solvent acrylic pressure-sensitive adhesive (PSA). New applications and technical specifications stimulate the continuous development of new methods of polymerization of solvent-free acrylate. New synthesis of solvent-free acrylics includes polymerization in the reactor with removal of the solvent and polymerization of the carrier. The polymerization process is connected with UV-crosslinking.

Copolymerizable Photoinitiators Based on Benzophenones and their Influence on Shrinkage of Photoreactive Acrylic PSAs

This manuscript describes a novel class of copolymerizable benzophenone photoinitiators and their influence on viscosity and molecular mass of acrylic pressure-sensitive adhesives (PSAs) during radical solvent polymerization and shrinkage of acrylic PSAs coated on PVC film and crosslinked using UV radiation.

New Copolymerizable Photoinitiators for Radiation Curing of Acrylic PSA

This article presents a new class of copolymerizable photoinitiators containing vinyloxycarbonyl groups, known such as organic carbonate or carbamate. Novel copolymerizable photoinitiators have been prepared through the reaction between vinyl chloroformate and hydroxyl groups containing photoreactive derivatives such as benzophenone-, acetophenone-, benzoine-and anthrachinone-derivatives. The main emphasis is given to the influence of this new class of unsaturated photoinitiators on UV-crosslinking process of acrylic pressure-sensitive adhesives (PSA). Moreover, the paper describes the influence of various parameters such as UV-initiated crosslinking time and concentration of unsaturated photoinitiators on relevant PSA properties like tack, peel adhesion and shear strength (cohesion).

Effect of side chain on wettability and adhesion performance of acrylic pressure-sensitive adhesives on thin silicon wafer

Acrylic pressure-sensitive adhesives (PSAs) need to show proper adhesion and improved wettability on the silicon wafer as the wafer becomes thinner. The acrylic copolymers were synthesized by solution radical polymerization of 2-ethylhexyl acrylate, ethyl acrylate, and acrylic acid with AIBN as an initiator. Adhesion performance and wettability of acrylic PSAs were studied depending on the content of lauryl side chains and the degree of crosslinking. The introduction of lauryl side chain was characterized by Fourier transform infrared spectroscopy. The adhesion performance of acrylic PSAs having lauryl side chain was investigated using contact angle, wettability, probe tack, peel strength, and cohesiveness tests. The wettability of acrylic PSAs was improved significantly with increasing the content of lauryl side chain.

아크릴계 점착제의 제조와 가교물성에 관한 연구

압력감응성 아크릴 점착제의 물성은 가교를 위한 관능성그룹을 가진 단량체를 이용하여 쉽게 물성을 조절할 수 있다. 본 연구에서는 두개의 다른 가교제, isocyanate 및 epoxy형 가교제에 따른 아크릴 점착제의 가교특성과 물성을 연구하였다. 2-Ethylhexyl acrylate, acrylic acid (AA)와 2-hydroxyethyl methacrylate를 주 단량체로 하여 이소시아네이트 또는 에폭시형 가교제로 가교한 점착제의 박리점착 특성, 볼텍, 유지력 및 수축성을 고찰하였다. 점착특성은 AA함량 증가와 더불어 증가하였고 가교점이 많고 ether와 같은 유연한 결합을 생성하는 에폭시형 가교제에서 우수한 물성을 나타내었다. The physical properties of the acrylic pressure sensitive adhesives (PSAs) can be easily controlled by a proper functional monomer which has functional groups for crosslinking. This study was to investigate the effect of crosslinking agents, isocyanate and epoxy types, of acrylic PSAs on adhesive properties. 2-Ethylhexyl acrylate, acrylic acid (AA), and 2-hydroxy ethyl methacrylate as monomer were used. The obtained samples with different AA contents were partially crosslinked with epoxy- or isocyanate-typed agent. Peel strength, balltack, holding power test and contraction percentage of the obtained PSA were evaluated. Most properties of acrylic PSAs were increased with AA content and acrylic PSAs with epoxy-typed crosslinking agent (4 crosslinking sites) which produces flexible link (ether), showed better properties than those of isocyanate-typed one (3 crosslinking sites).

아크릴산 함량 및 무기물 충전제가 UV 경화형 아크릴 점착테이프의 물성에 미치는 영향

아크릴 점착테이프는 자동차, 전기전자 및 디스플레이 모듈 접합에 사용된다. 본 연구는 이러한 모듈 접합에 사용되는 고강도 준구조형 점착테이프 제조를 위해 2-ethylhexylacrylate(2-EHA)와 acrylic acid(AAC)를 사용하여 UV 조사에 의한 광중합 및 점착테이프 제조를 위해 광경화를 진행하였고, AAC의 함량 및 무기물 충전제 <TEX>$SiO_2$</TEX> 함량에 따라 아크릴 점착테이프의 물성에 미치는 영향을 고찰하였다. 공단량체로 사용된 AAC의 함량이 많을수록 아크릴고분자 사슬의 강직성이 증가하여 초기 점착력이 낮았고, 시간경과에 따라 점착력이 증가하였으며 테이프의 젖음성, 접촉각 및 SEM 이미지를 통해 확인할 수 있었다. 충전제를 첨가하지 않은 점착테이프의 박리강도와 전단접착강도는 반비례 관계였으나 충전제를 첨가하면 함량 증가에 따라 박리강도 증가와 함께 전단접착강도가 증가하는 비례관계를 보였다. 이러한 상관관계로부터 고강도 준구조형 접착물성을 필요로 하는 용도에 최적화된 아크릴 점착테이프를 제시할 수 있었다. Acrylic pressure sensitive adhesive (PSA) tapes were used for the automotive, the electrical and the electronic industries and the display module junction. In this study, the manufacture of high-strength structural tape used 2-ethylhexyl acrylate (2-EHA) and acrylic acid (AAC), and UV irradiation for photo-polymerization, and the semi-structural properties of acrylic PSA tape with the AAC content and inorganic filler <TEX>$SiO_2$</TEX> content were investigated. The initial adhesion strength was lowered by the rigidity of molecule chains due to the use of AAC, and the adhesion strength increased with increasing wetting time. The wetability, contact angle, and SEM images of PSA tapes with various contents of AAC were determined. Without filler, the peel strength and dynamic shear strength of PSA tape showed inverse correlation but the peel strength and dynamic shear strength increased with increasing filler content. From these correlations the PSA tapes could be optimized for the applications requiring high performance.