Adhesion electron resists

Epoxy resins are superior in heat resistance, adhesion, corrosion resistance and also mechanical properties among thermosetting resins and are widely used for coatings, adhesives, electric insulating materials and matrices for FRP in areas such as aircrafts, electronics, electric power, and building and civil engineering. 

Current interest in siloxane polyimides is triggered by opportunities for such materials in military, aerospace and electronic applications as coatings, films, adhesives, molding compounds and composite matrix materials which are subject to demanding operating conditions. These polymers offer advantages such as excellent interlevel adhesion, plasma resistance, low water absorption, and stability at high temperatures. 

Uses Epoxy for adhesives (anaerobic, binder, pressure-sensitive, structural), coatings (glass, metal, optical, paper, plastic, wood, PVC floor), electronics, inks (flexo, gravure, litho, offset, screen), sealants Features Fast cure response gtxxl chem. resist., film hardness, adhesion, abrasion resist., water resist. 

Uses Urethane-acrylic for lithographic/offset/screen inks, wood/paper coatings, electronics, photopolymers, elastomers, adhesives Features Offers flexibility, water resist., chem. resist., adhesion, heat resist., abrasion resist., impact str. 

Uses Flexibilizer, water resist, aid for urethane adhesives, electronics coatings flexibilizer, impact resist, aid for epo) adhesives, electronics... 

Non-flammable polymers are polymers that are resistant to degradation and burning at high temperatures. In recent years there has been an increasing demand for fire retardant versions of a range of plastics. These types of polymers are particularly important in areas where there are enclosed spaces such as in skyscrapers, boats, trains and aeroplanes. Non-flammable polymers are also found in adhesives, electronic insulation and in military applications such as canvas tents and in domestic applications such as furniture, clothes, bedding, upholstery and electrical goods. 

The epoxide resins are a class of materials that possess all the properties required to make them useful for a wide range of applications throughout the electronics industry. They have good electrical properties, low shrinkage, good adhesion and resistance to thermal and mechanical shock, whilst also possessing resistance to moisture, solvents and general chemical attack. 

In applications involving orbital vehicles such as satellites and instrument platforms, high-performance/high-temperature adhesives may be expected to endure thermal cycling in the temperature range of—160-125°C. Furthermore, in such applications, the adhesive must resist ionizing radiation, such as radiation from photons, electrons, and ultraviolet rays. 

A novel design of multilayer-hole structure was employed to investigate the geometrieal effects of the holes conneeting the multilayers of a novel prototype designed to be used in electronic components in circuit boards, on their electrical resistances. The bonded sample resistance not only depends on the bulk adhesive electrical resistance, but also on the interfacial contact effect between the adhesive and the adherend. An empirical relationship was proposed between the contact resistance R, the hole diameter D), and the plate thickness (77 ), for Epon830/Ni/DETA adhesive after cure with 60 wt% of Ni as the filling material. Ohm s law adequately describes the hole depth effects on the prototype s electrical resistance. 

Cyanoacrylate adhesives (Super-Glues) are materials which rapidly polymerize at room temperature. The standard monomer for a cyanoacrylate adhesive is ethyl 2-cyanoacrylate [7085-85-0], which readily undergoes anionic polymerization. Very rapid cure of these materials has made them widely used in the electronics industry for speaker magnet mounting, as weU as for wire tacking and other apphcations requiring rapid assembly. Anionic polymerization of a cyanoacrylate adhesive is normally initiated by water. Therefore, atmospheric humidity or the surface moisture content must be at a certain level for polymerization to take place. These adhesives are not cross-linked as are the surface-activated acryhcs. Rather, the cyanoacrylate material is a thermoplastic, and thus, the adhesives typically have poor temperature resistance. 

Polyimides (PI) were among the eadiest candidates in the field of thermally stable polymers. In addition to high temperature property retention, these materials also exhibit chemical resistance and relative ease of synthesis and use. This has led to numerous innovations in the chemistry of synthesis and cure mechanisms, stmcture variations, and ultimately products and appHcations. Polyimides (qv) are available as films, fibers, enamels or varnishes, adhesives, matrix resins for composites, and mol ding powders. They are used in numerous commercial and military aircraft as stmctural composites, eg, over a ton of polyimide film is presently used on the NASA shuttle orbiter. Work continues on these materials, including the more recent electronic apphcations. 

Polyimides of 6FDA and aUphatic diamines with good low temperature processkig and low moisture swelling are known to be useful as hot-melt adhesives (109). Aluminum strips bonded by this polymer (177°C/172 kPa (25 psi) for 15 min) exhibited a lap-shear strength of 53 MPa (7690 psi) at room temperature and 35 MPa (5090 psi) at 100°C. The heat- and moisture-resistant 6F-containing Pis useful ki electronic devices are prepared from... 

Small amounts of TAIC together with DAP have been used to cure unsaturated polyesters in glass-reinforced thermo sets (131). It has been used with polyfunctional methacrylate esters in anaerobic adhesives (132). TAIC and vinyl acetate are copolymerized in aqueous suspension, and vinyl alcohol copolymer gels are made from the products (133). Electron cure of poly(ethylene terephthalate) moldings containing TAIC improves heat resistance and transparency (134). 

Epoxies. The unique chemical and physical properties such as excellent chemical and corrosion resistances, electrical and physical properties, excellent adhesion, thermal insulation, low shrinkage, and reasonable material cost have made epoxy resins (qv) very attractive in electronic apphcations. 

The above measurements all rely on force and displacement data to evaluate adhesion and mechanical properties. As mentioned in the introduction, a very useful piece of information to have about a nanoscale contact would be its area (or radius). Since the scale of the contacts is below the optical limit, the techniques available are somewhat limited. Electrical resistance has been used in early contact studies on clean metal surfaces [62], but is limited to conducting interfaces. Recently, Enachescu et al. [63] used conductance measurements to examine adhesion in an ideally hard contact (diamond vs. tungsten carbide). In the limit of contact size below the electronic mean free path, but above that of quantized conductance, the contact area scales linearly with contact conductance. They used these measurements to demonstrate that friction was proportional to contact area, and the area vs. load data were best-fit to a DMT model. 

The influence of the gel content in polyisoprene-tackifier blends on creep resistance and peel behaviour have been recently studied [62]. The gel content was achieved by cross-linking the adhesives with electron beam irradiation. The molecular weight of the soluble fraction in the blend was always dominated by that of the initial elastomer. Creep resistance was achieved either through molecular weight increases or gel content increases. However, the peel strength is strongly... 

All of the types of repairs described can be accomplished using electron/X-ray curing and suitable electron-curable adhesive systems. The advantages ol using an electron accelerator are faster curing cycles, short turn-around time, and higher-temperature-resistant bonds, cured at ambient temperatures. 

The polymers were dissolved in methylisobutylketone (MIBK) and spin-coated on oxjdized silicon wafers (1100 X thick Si02 layers) to form 5000 A thick films. After a prebaking to improve adhesion to the substrate, the resist samples were irradiated 0 through the mask (A) using the Al K 152 emission line at 8.3 A as X-ray source. The electron beam gun was operated at a 300 W power and the source to sample distance was U.9 cm. Taking into account the absorption of the aluminum foil mask,the different X-ray fluxes available on the sample were calculated from the relation given by (9) ... 

Uses. About 35-40% of the methanol made is converted to formaldehyde. That s not because the embalming business is so good. Formaldehyde is a feedstock for amino and phenolic resins, which are used as adhesives in plywood, and in the automotive and appliance industry to make parts (all the agitators in washing machines used to be made out of phenolic resins). It is used as feedstock for hexamethylene tetramine, used in electronic plastics for pentaerythritol, used for making enamel coatings and for floor polish and inks for butanediol, a chemical intermediate and for acetic acid, which is widely used itself as a feedstock and solvent and warrants its own treatrnent later on. In the textile business, formaldehyde is used to make fire retardants, mildew resistant linens, and permanent press clothing. 

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