Acrylics Pressure-sensitive adhesives

Mangipudi et al. [63,88] reported some initial measurements of adhesion strength between semicrystalline PE surfaces. These measurements were done using the SFA as a function of contact time. Interestingly, these data (see Fig. 22) show that the normalized pull-off energy, a measure of intrinsic adhesion strength is increased with time of contact. They suggested the amorphous domains in PE could interdiffuse across the interface and thereby increase the adhesion of the interface. Falsafi et al. [37] also used the JKR technique to study the effect of composition on the adhesion of elastomeric acrylic pressure-sensitive adhesives. The model PSA they used was a crosslinked network of random copolymers of acrylates and acrylic acid, with an acrylic acid content between 2 and 10%. 

Uses Tackifier, binder, plasticizer for inks, textile sizes and finishes, latex modification, paints, adhesives adhesion promoter (acrylic pressure-sensitive adhesives) laminating heat sensitizer for rubber latex pigment binder in textile finishing protective colloid in emulsions flexibilizer, vise, control agent for photoresist coatings semiperme-able membranes (reverse osmosis plants) antistat, binder, film-former in cosmetics finish component for poly (phenyleneterephthalamide) food-pkg. resins in food-contact PU resins Regulatory FDA 21 CFR 175.105,177.1632,177.1680 Manuf/Distrib. Aldrich BASF ISP... 

Thomas Sanderson, "Water-Based, Acrylic Pressure-Sensitive Adhesives", Adhesives Age, 2, No. 12, 31 (1978). ... 

Journal of Applied Polymer Science 81, No.9, 29th August 2001, p.2109-17 EFFECT OF NETWORK MORPHOLOGY ON ADHESIVE PERFORMANCE IN EMULSION BLENDS OF ACRYLIC PRESSURE SENSITIVE ADHESIVES... 

Zollner, S., UV-curable acrylic pressure-sensitive adhesives. Features, Mechanisms, Milestones (pp. 543-549), Proc. RadTech Europe, Berlin, 1999. 

The results are reported of an investigation into the stability, in-vitro drug delivery and adhesive properties of drug-in-adhesive transdermal drug delivery systems. These systems are composed of a flexible backing film, a fluoropolymer release liner and active adhesives, which vary in their monomeric compositions and functionalities. The adhesives are composed of an acrylic pressure-sensitive adhesive, an amine-compatible silicone pressure-sensitive adhesive and methylphenidate base, as the drug. 4 refs. 

Six micrometre PEEK film has recently replaced polyethylene terephthalate (PET) as a cover film for thermal-acoustic and burn-through insulation. PET failed the new FAA flame performance tests and alternative materials such as PVDF and polyimides were too dense or not available in the required film thicknesses. The film is installed using PEEK tape coated in an acrylic pressure-sensitive adhesive. PEEK fibre also finds application in high-temperature acoustic blankets based on the Helmholtz resonator effect [2]. 

Lakrout, H., Sergot, P. Creton, C. (1999). Direct Observation of Cavitation and Fibrillation in a Probe Tack Experiment on Model Acrylic Pressure-Sensitive-Adhesives. Journal of Adhesion, Vol. 69, pp. 307-359, ISSN 0021-8464... 

Costanzo, J. A., and Gehman, D. R., Aqueous Acrylic Pressure Sensitive Adhesives for Labels and Overlays, TAPPI Conference (Fall, 1983). 

Pressure sensitive adhesive tapes are used for holding and anchoring lead wires to the outer wrap of transformer coils, capacitor wrapping, protection of leads and coils, and other similar applications. Adhesive transfer films are used to hold insulating material in position. Natural rubber based pressure sensitive adhesives have poor solvent resisitance unless they are cross-linked. Many modifications are possible. Synthetic rubber has better stability than natural rubber and better solvent and ozone resistance. Acrylic pressure sensitive adhesives have the best balance of properties. They maintain their... 

Acrylic monomers and their Tg, Me, and typical weight % addition into an acrylic pressure-sensitive adhesive... 

A further disadvantage of emulsion-based systems is the difficulty of drying them. The high heat of vaporization of water makes it impractical to dry films above 50 pm since inordinately long dryers would be required. Most emulsion acrylic pressure-sensitive adhesives are coated to about 25 pm thickness. 

Fig. 8-15 Peel strength of an acrylic pressure sensitive adhesive depending on the dwell time, according to W. Druschke [27].

Up to now, poly(methyl methacrylate) and methyl methacrylate copolymers e.g. with styrene, butyl acrylate and dodecyl methacrylate) have been the most widely used acrylic polymers for nanocomposite preparation by emulsion and suspension polymerization. Less research has been based on other acrylic polymers, such as polyacrylonitrile, poly(butyl acrylate), " poly(butyl methacrylate), poly(2-ethylhexyl acrylate), poly(2-hydroxyethyl methacrylate), polyacrylamide, poly(lauryl acrylate)," poly(butyl acrylate-co-styrene)," " poly(acrylonitrile-co-styrene), poly(acrylonitrile-co-meth-acrylate)," poly(ethyl acrylate-co-2-ethylhexyl acrylate)" and poly(2-ethylhexyl acrylate-co-acrylic acid)," and sometimes small amounts of hydophilic acrylic monomers, such as hydroxyethyl methacrylate, methacrylic acid and acrylic acid, have been used as comonomers. " Therefore, it may be stated that, so far, the preparation of acrylic-clay nanocomposites has been based mainly on high glass transition temperature polymers, although nanocomposite materials with lower glass transition temperatures with improved or novel properties, which exhibit a balance of previous antagonistic properties, can also be achieved and are very desirable. Regarding nanocomposites of low glass transition temperature polymers, such as poly(butyl acrylate), poly(ethyl acrylate) and poly(2-ethylhexyl acrylate), which have been utilized as the main components of acrylic pressure-sensitive adhesives, little information is available. 

Adhesives. Acryhc emulsion and solution polymers form the basis of a variety of adhesive types. The principal use is in pressure-sensitive adhesives, where a film of a very low T (<—20 " C) acrylic polymer or copolymer is used on the adherent side of tapes, decals, and labels. Acrylics provide a good balance of tack and bond strength with exceptional color stabiUty and resistance to aging (201,202). AcryUcs also find use in numerous types of constmction adhesive formulations and as film-to-film laminating adhesives (qv). 

Other Plastics Uses. The plasticizer range alcohols have a number of other uses in plastics hexanol and 2-ethylhexanol are used as part of the catalyst system in the polymerization of acrylates, ethylene, and propylene (55) the peroxydicarbonate of 2-ethylhexanol is utilized as a polymerization initiator for vinyl chloride various trialkyl phosphites find usage as heat and light stabHizers for plastics organotin derivatives are used as heat stabHizers for PVC octanol improves the compatibHity of calcium carbonate filler in various plastics 2-ethylhexanol is used to make expanded polystyrene beads (56) and acrylate esters serve as pressure sensitive adhesives. 

Heteroatom functionalized terpene resins are also utilized in hot melt adhesive and ink appHcations. Diels-Alder reaction of terpenic dienes or trienes with acrylates, methacrylates, or other a, P-unsaturated esters of polyhydric alcohols has been shown to yield resins with superior pressure sensitive adhesive properties relative to petroleum and unmodified polyterpene resins (107). Limonene—phenol resins, produced by the BF etherate-catalyzed condensation of 1.4—2.0 moles of limonene with 1.0 mole of phenol have been shown to impart improved tack, elongation, and tensile strength to ethylene—vinyl acetate and ethylene—methyl acrylate-based hot melt adhesive systems (108). Terpene polyol ethers have been shown to be particularly effective tackifiers in pressure sensitive adhesive appHcations (109). 

A number of higher poly(vinyl ether)s, in particular the ethyl and butyl polymers, have found use as adhesives. When antioxidants are incorporated, pressure-sensitive adhesive tapes from poly(vinyl ethyl ether) are said to have twice the shelf life of similar tapes from natural rubber. Copolymers of vinyl isobutyl ether with methyl acrylate and ethyl acrylate (Acronal series) and with vinyl chloride have been commercially marketed. The first two products have been used as adhesives and impregnating agents for textile, paper and leather whilst the latter (Vinoflex MP 400) has found use in surface coatings. 

Acrylics are some of the most common and most versatile materials used in the PSA industry. Although the basic monomers and some of the acrylic polymers have been known for about a century, their commercial application as pressure sensitive adhesives did not happen until after the Second World War. 

Among the different pressure sensitive adhesives, acrylates are unique because they are one of the few materials that can be synthesized to be inherently tacky. Indeed, polyvinylethers, some amorphous polyolefins, and some ethylene-vinyl acetate copolymers are the only other polymers that share this unique property. Because of the access to a wide range of commercial monomers, their relatively low cost, and their ease of polymerization, acrylates have become the dominant single component pressure sensitive adhesive materials used in the industry. Other PSAs, such as those based on natural rubber or synthetic block copolymers with rubbery midblock require compounding of the elastomer with low molecular weight additives such as tackifiers, oils, and/or plasticizers. The absence of these low molecular weight additives can have some desirable advantages, such as ... 

Acrylic polymers are also important in the preparation of other classes of adhesives, especially pressure sensitive adhesives. This discussion will be limited to adhesives that cure by the reaction of unsaturated acrylic functional groups. These adhesives are also sometimes termed Methacrylate , Methacrylic or Structural Acrylic adhesives. This is consistent with the long-standing habit of organic chemists to assign multiple names to the same substance. 

Pressure-sensitive adhesives (PSAs) based on acrylic, natural rubber and silicone are employed primarily for ease of application. To name Just a few applications, PSAs bond decals to surfaces, interior decorative surfaces to interior panels, interior trim pieces in place directly or hook and loop tape for the same purpose, structural shims in place during manufacturing and acoustic (sound deadening) materials to body skin interior surfaces. Tape products with pressure-sensitive adhesive on one or both surfaces are used for such functions as cargo compartment sealing, as a fluid barrier to prevent spills and leaks in the lavatories and... 

Aqueous, removable, pressure-sensitive adhesive compositions, useful for high-performance applications, comprise a mixture of a copolymer of alkyl (meth)acrylate and N-substituted (poly)amide of (meth)acrylic acid and a copolymer of alkyl (meth)acrylate and ethylenically unsaturated carboxylic acid, where at least one of the copolymers is an emulsion copolymer. Polyoxyalkyl-enes and phosphate esters may be used as surfactants [234]. 

Polystyrene-PDMS block copolymers4l2), and poly(n-butyl methacrylate-acrylic acid)-PDMS graft copolymers 308) have been used as pressure sensitive adhesives. Hot melt adhesives based on polycarbonate-PDMS segmented copolymers 413) showed very good adhesion to substrates with low surface energies without the need for surface preparation, such as etching. 

A different approach, although stdl working with essentially non-fiinctional polymers has been exemplified [114,115], in which, a 100% solid (solvent free) hot melt has been irradiated to produce pressure-sensitive adhesives with substantially improved adhesive properties. Acrylic polymers, vinyl acetate copolymers with small amounts of A,A -dimethylaminoethyl methacrylate, diacetone acrylamide, A-vinyl pyrrohdone (NVP) or A A have been used in this study. Polyfunctional acrylates, such as trimethylolpropane trimethacrylate (TMPTMA) and thermal stabilizers can also be used. 

NR, styrene-butadiene mbber (SBR), polybutadiene rubber, nitrile mbber, acrylic copolymer, ethylene-vinyl acetate (EVA) copolymer, and A-B-A type block copolymer with conjugated dienes have been used to prepare pressure-sensitive adhesives by EB radiation [116-126]. It is not necessary to heat up the sample to join the elastomeric joints. This has only been possible due to cross-linking procedure by EB irradiation [127]. Polyfunctional acrylates, tackifier resin, and other additives have also been used to improve adhesive properties. Sasaki et al. [128] have studied the EB radiation-curable pressure-sensitive adhesives from dimer acid-based polyester urethane diacrylate with various methacrylate monomers. Acrylamide has been polymerized in the intercalation space of montmorillonite using an EB. The polymerization condition has been studied using a statistical method. The product shows a good water adsorption and retention capacity [129]. 

The tacky polymeric microspheres that comprise the pressure-sensitive adhesive layers of repositionable notes are patented inventions. One such material (U.S. Patent 5,714,237) is prepared by a free-radical polymerization reaction of isooctyl acrylate (Fig. 14.3.1) in the presence of polyacrylic acid with a chain-... 

Adhesives, 1 501-502, 524-553. See also Adhesion Pressure-sensitive adhesives (PSAs) acrylic ester polymers, 1 390 alkanolamines from olefin oxides and ammonia, 2 135... 

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