Substrate impact resistance

Special, uv-curable epoxy resins (qv) for substrate disks for optical data storage (Sumitomo BakeHte, Toshiba) excel by means of their very low birefringence (<5 nm/mm) and high Young s modulus. Resistance to heat softening and water absorption are similar to BPA-PC, but impact resistance is as low as that of PMMA. 

Waldvogel and Poulikakos1501 extended the model and numerical techniques of Zhao et al.13681 by incorporating solidification and droplet-substrate contact resistance in the heat transfer model. They conducted both theoretical and experimental studies on the impact and solidification of molten solder droplets on a multilayer substrate. The theoretical model was based on the Lagrangian formulation, and accounted for a host of thermal-fluid phenomena,... 

There are several interesting applications reported in the literature, such as insulated wire and cable, UV cross-linking of drawn fibers, and tapes from ultra-high-molecular-weight polyethylene. Semi-interpenetrating networks (IPNs) from acrylates and polyurethanes are suitable as UV curable adhesives with high elasticity, good impact resistance, and excellent adhesion to a variety of substrates. ... 

A hard disk typically consists of an Al-Mg alloy (or glass substrates), a NiP undercoat, magnetic layer, carbon overcoat, and a very thin layer of lubricant, as illustrated in Fig. 1.1. Since the Al-Mg alloy is mechanically soft, a hard undercoat is applied to provide adequate impact resistance to the head-disk interactions. The magnetic layer where the information is stored is typically sputtered directly onto a bare NiP/Al-Mg disk substrate. A carbon overcoat is sputtered to enhance wear and/or corrosion resistance. Finally, a molecularly thin layer of PFPEs (the subject of this chapter) along with airbearing is added to further reduce both the wear of the overcoat and stiction between the head and disk. 

Choosing an adhesive for a medical application follows the same process as choosing an adhesive for any other purpose. Criteria include the particular substrates to be joined, strength requirements, type of loading, impact resistance, temperature resistance, fluid resistance, and processing requirements. However, the function of many medical devices requires at least two other important criteria resistance to sterilization and low toxicity. As a result, several important standards and regulations have been developed in the industry. 

Regarding the properties required of the solidified materials in 2D printing, the most important properties are generally related to thin material layers, such as color, adhesion to the substrate, hghtfastness, and scratch resistance, whereas in 3D printing, the most important properties are generally related to the bulk material mechanical and thermomechanical properties, for example tensile and flexural properties, impact resistance, and Glass Transition Temperature (Tg). 

Low surface tension causes excellent wetting of substrate which is required for good adhesion of the coating to the surface. Good adhesion promotes good corrosion resistance, impact resistance, and chip resistance. 

The chemical literature reveals relatively new and varied interests for nitrile elastomer-modification of epoxy resins in diverse areas of coatings and primers. Desirable properties such as impact resistance, mandrel bend and adhesion improvement are attainable with little or no sacrifice in critical film properties. In some instances, it is documented that proper elastomer modification of select epoxy coatings will enhance corrosion and moisture resistance. This may relate to better film/substrate adhesion durability. The combined literature, journal and patent, has led to continuing study of nitrile elastomer modified epoxy coatings. 

The initial monomers, dipropargyl ethers of bis(s)phenols and their polymers, are available in a one-step easy preparation in quantitative yield. They are suitable for industrial production in large scale and potentially available at a low price. The coatings based on these linear polymers require low energy for curing. Their radiation cure is completed for several seconds in the absence of a photosensitizer at room temperature, whereas thermal cure proceeds for half an hour at 100°C. The initial unoptimized properties of these coatings appear very attractive. They exhibit excellent adhesion to metal substrates, hardness, flexibility, impact resistance, good solvent resistance, low water absorption, and... 

When impact resistance and/or strength is required, it can be improved dramatically by the rubber sandwich technique. In this case, a rubber sheet bonded between the rigid plastic or metal substrates will absorb all peel and impact forces. It is also useful in absorbing stresses when thermal expansion and contraction occur. 

Aramid para-aramid, 2.8 Pa strength, 70 GPa modulus chopped staple or fibrid (pulp) 10-150 g/m2 Tensile strength up to 8 N/mm Density 80 kg/mm Improved impact resistance Smooth finish Good wear resistance Can be blended with conductive fiber Superior temperature resistance Aerospace adhesive carriers Automotive improved stone impact resistance Defence radar cross section Recreation skis, snow and surf boards, surf boards, canoes Industrial substrate for friction products wear resistance for high-speed rolls Electrical printed circuit boards... 

Chem. Descrip. Hydroxyethyl acrylate CAS 818-61-1 EINECS/ELINCS 212-454-9 Uses Monomer for prod, of resins used in high performance coatings, pressure-sensitive adhesives and coatings for plastics and flexible substrates, radiation-cured resins, emulsion polymers and additives for personal care prods, and ion exchange resins Features Provides better adhesion, impact resist., flexibility and faster reactivity than methacrylate analogs Properties Colorless clear mobile liq. si. acrylic odor completely misc. with water, common org. soivs. dens. 1.101 g/ml vise. 8 cps (15.5 C) vapor pressure 0.1 mm Hg t.p. -30 C b.p. 192 C flash pt. (PMCC) 101.1 C 97.5% min. assay... 

Chem. Descrip. Hydroxypropyl acrylate CAS 25584-83-2 EINECS/ELINCS 247-118-0 Uses Monomer for prod, of resins used in high performance coatings, heat-cured topcoats, pressure-sensitive adhesives and coatings for plastics and other flexible substrates, radiation-cured resins Features Provides better adhesion, impact resist., flexibility and faster reactivity than methacrylate analogs... 

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