Acrylic-based adhesives

The potential of using extrinsic (fluorescent) probes for monitoring the initial stages of oxidation was explored for the photo-oxidation of a UV-cured aliphatic polyurethane-acrylate-based adhesive [68]. The two probes investigated were p-dimethylamino salicylic acid (p-DASA) and 2, 7 -difluorescein (Oregon Green... 

One of the most popular uses of radiant curing is the advancement (viscosity increase) or crosslinking of pressure-sensitive adhesives. These applications have been satisfied mostly with acrylate-based adhesive systems. With epoxy-based adhesives, the main applications are electrical and electronic components, the bonding of large aerospace structures such as composites, and the bonding of transparent substrates such as glass and plastic. 

More modem systems include polyurethane and acrylic-based adhesives and twopart curing adhesives are gaining popularity. 

The non-isothermal analysis was undertaken for nonirradiated sample of the polyurethane-acrylate-based adhesive. And from the Arrhenius plot of the CL intensity over the temperature range 60-150°C, the activation energy for CL emission was determined to be 85 kJ mol-1. 

TABLE 3.8 Kinetic Data of Chemiluminescence from the UV-Cured Aliphatic Polyurethane-Acrylate-Based Adhesive L350, at 100°C Under Nitrogen, After UV Irradiation... 

To analyze the oxidation level of the adhesive by fluorescence, the fluorescence of the two probes as a function of the CL-parameters, maximum intensity, and decay rate, for the polyurethane-acrylate-based adhesive, were plotted (Fig. 3.8). Quenching of fluorescence followed the same kinetics as the chemiluminescence increase during UV-exposure. The two fluorescent probes used were sensitive to the formation of oxidation products. Therefore, in this work, good correlations between fluorescence and chemiluminescence were established, which allow monitoring photodegradation by using extrinsic emission fluorescent probes and/or CL emission from bulk material. 

CL has been employed to study the mechanism of degradation in polymers such as UV-cured aliphatic polyurethane-acrylate-based adhesives. In styrenic block copolymers, SEBS, the order of the reaction was determined, and the efficiency of antioxidants was evaluated. Also, the relationship between thermooxidation of SEBS and morphology was established, indicating that for these copolymers the oxidation started in the interfacial region. 

CAS 10287-53-3 EINECS/ELINCS 233-634-3 Uses Synergist to improve effectiveness and efficiency of photoinitiators used in UV-curable acrylate-based adhesives, printing inks, photoresist, wood varnishes, and metal coatings Properties Wh. to off-wh. crystalline solid sweet odor m.w. 193.25 m.p. 61-64 C 0.2% max. moisture Toxicology TSCA listed... 

Surprisingly, using an acrylate-based adhesive (A 7275, Beiersdorf), the crosslinkers containing aromatic compounds did not show the expected increase in release force values with a higher content of organic compounds (Fig. 2). This was confirmed in various measurements in which the SiH/vinyl ratio as well as the type of adhesive and the method of sticking (inline or offline) were modified. When a rubber-based adhesive (RP 51, Raflatec) was stuck onto the coated surfaces, an increase in the release force values was also observed in case of C2, whereas the other crosslinkers showed approximately the same release force values for all compositions. 

Modern acrylate-based adhesive tapes are recommended. 

Protect press-fit PTH holes from extraneous solder, flux, surface-mount adhesive, spot mask, or other contaminants from surface-mount, wave-solder, or hand-solder processes. Use of a wave pallet or high-temperature masking tape (e.g., polyimide tape) to shield press-fit locations during other processing is advisable. If tape is used, inspect first articles to ensure that high-temperature masking tape residue does not foul press-fit holes. Polyimide tape with acrylic-based adhesive is best for this application, as residues will be absent or minimal. 

Figure 13 displays the assembled prototype in which a newly invented acrylic-based adhesive was used for bonding plastics with plastics and metals. Subsequently, Volkswagen of Mexico has introduced other thermoplastic composite solutions for its FEC systems in the Golf, Jetta, and Bora, using different methods to join to the body-in-white. ... 

Rexible film substrates are available as single- and double-sided copper-clad laminates. Copper foil is generally laminated to the base material by means of epoxy- or acrylic-based adhesives. 

Acrylic-based polymers were first produced in Germany in 1901. Subsequent work has produced a range of acrylic-based adhesives with the following general features ... 

Lord Corporation introduced adhesives containing methacrylated phosphate monomers that gave much-improved thermal and atmospheric durability, and Dymax Corporation introduced their aerobic acrylics that were less sensitive to inhibition by atmospheric oxygen. Dow Automotive, 3M, and Loctite recently introduced two-part acrylic-based adhesives that can bond many low-surface-energy plastics, including many grades of polypropylene, polyethylene, and thermoplastic polyolefins without special surface preparation (see Section 4.2.2 for a description of this technology). 

Polyester resins can be used as a hot melt adhesive in shoe and textile industries. Cyanoacrylates and anaerobic adhesives are the cross-linked versions of acrylic-based adhesives, cured by catalyst reactions. 

The hardening of the adhesives happens either through a chemical reaction or through simply physically binding to the surface. The chemical reaction in case of a one-part adhesive depends on the chemical nature of the adhesive (Habenicht 1990). So do polyurethane- or silicone-based adhesives cure in the presence of moisture, whereas cyan-acrylic-based adhesives are inhibited by the presence of oxygen and cure under nonaerobic conditions. Other adhesives like epoxy one-part adhesives cure with heat. Two-part adhesives contain beside the resin part, a hardener part which consists of reactive molecules or polymers which react together with the resin part. Typical examples are epoxy- or acrylic-based adhesive formulations. 

Acrylic-based adhesives and hardener compounds of two-part formulations can have a strong odor and would require working under proper ventilation... 

Depending on the chemistry of the adhesive, the adhesion to different substrates (Dettner 1991) and the tolerance for surface contamination is different. Epoxy and acrylic-based adhesives bond well to a variety of different surfaces like metals, aluminium, or composites and tolerate some degree of surface contamination like oil if cured by heat. They do not adhere well to low-energy surfaces like plastic. Two-part epoxy formulations need a cleaning of the surface to remove any contamination. Special two-part acrylic-epoxy hybrid adhesives are able... 

These bubbles may originate from the adhesive packaging but can also be due to shrinkage of the adhesive as it cures. Most of the acrylic-based adhesives will shrink on cure slightly whilst epoxies tend to show lower shrinkage. Applying smaller volumes of adhesive will minimise the shrinkage voids and so in some applications it may be necessary to apply the adhesive in two lots . 

Firstly is an epoxy-based material adhesive. Although some people use the term epoxy as a generic reference to aU high-performance engineering adhesives, it has a specific meaning within flie adhesive world. It is also different from other adhesive types, particularly the acrylic-based adhesives. 

Chem. Descrip. Synthetic nonsilicone, non-mineral oil Uses Defoamerfor polyvinyl acetate, polyvinyl alcohol, and acrylic-based adhesives... 

Advantage AM357 Defoamer Advantage AM831 Defoamer defoamer, acrylic-based adhesives... 

Similarly two-part toughened acrylic based adhesives have been used where a small component has to be bonded to a very large assembly and where heating the whole assembly was neither economic nor practical. 

Other commercially snccessful reactive acrylic-based adhesives are mixtures of methacrylate polymers dissolved in methyl methacrylate (MMA) monomers. Extensive research and development of these adhesives first introduced in the 1960s have led to what is termed high-performance acrylic adhesives. These products are supplied as two separate components to be mixed prior to an application. A peroxide in one component and an amine or metal salt (reducing agent) in the other initiate a free-radical polymerization of the MMA upon mixing [16]. 

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