Insulative adhesives

The principal chemical markets for acetylene at present are its uses in the preparation of vinyl chloride, vinyl acetate, and 1,4-butanediol. Polymers from these monomers reach the consumer in the form of surface coatings (paints, films, sheets, or textiles), containers, pipe, electrical wire insulation, adhesives, and many other products which total biUions of kg. The acetylene routes to these monomers were once dominant but have been largely displaced by newer processes based on olefinic starting materials. 

Because of increased production and the lower cost of raw material, thermoplastic elastomeric materials are a significant and growing part of the total polymers market. World consumption in 1995 is estimated to approach 1,000,000 metric tons (3). However, because the melt to soHd transition is reversible, some properties of thermoplastic elastomers, eg, compression set, solvent resistance, and resistance to deformation at high temperatures, are usually not as good as those of the conventional vulcanized mbbers. AppHcations of thermoplastic elastomers are, therefore, in areas where these properties are less important, eg, footwear, wine insulation, adhesives, polymer blending, and not in areas such as automobile tires. 

Plywood adhesive, 48% fibrous and granulated wood adhesive, 16% insulation adhesive, 13% laminate adhesive, 6% molding compounds, 5% foundry adhesive, 3% miscellaneous, 9%... 

We thank the authors and reviewers of each of the papers. We also express our appreciation to the myriad chemists and chemical engineers who have contributed and will continue to contribute to progress in all aspects of rocket propulsion—propellants, structural materials, insulation, adhesives, igniters, process control, and safety. 

The imager comprises a silicon substrate 1 in which a read-out circuit such as a CCD is integrated. The read-out circuit has input regions 2 and metal electrodes 3. An array of photovoltaic detector elements 10 are formed in a p-type mercury cadmium telluride body 11 which is mounted by an insulating adhesive 21 on the substrate. Each detector element... 

Low Temperature Strength of Epoxy Resin Insulation Adhesive, Insulation, December 1958. 

Cellulose Ethers and Polymerisates cellulose and emulsion powders for coatings, mortars, building materials, insulation, adhesives, and tin for the pharmaceutical and food industries. Polyvinyl alcohol/butyral for adhesives, paper, textile processing, inks, paints and laminated glass. 

Chil Spray. [Childers Prods.] Insulation adhesive. 

Organosiloxanes are very heat resistant, so they do not easily melt, like most other organic compounds. They are also water-repellant and can withstand extremes of sunlight, moisture, cold, and attack by most chemicals. These properties make them useful for protective coatings, electrical insulation, adhesives, lubricants, paints, and rubber-like materials. Some silicones are also used to make nonstick... 

Packing films, insulation adhesive tapes, coats, lining, melt-blown vessels, containers, structural products, electroinsulating seals, self-lubricating antifrictional materials. 

CH2=CHC1 (vinyl chloride) (CH2-CHC1) Poly(vinylchloride), PVC Pipes, floor covering, insulation, adhesives, films, credit cards... 

Nonconductive or electrically insulative adhesives are used where electrical shorting may be a problem or where electrical isolation is required. Nonconductive adhesives are available in either paste or film form and are generally filled with silica or alumina to provide optimum flow properties for dispensing and to improve their thermal conductivities. 

To function as electrical conductors, epoxies and other polymer resins, because they are inherently insulators, must be filled with electrically conductive particles such as metals. The selection of electrically conductive or insulative adhesives is based largely on their conductivities or, conversely, on their volume resistivities. Electrically conductive adhesives should have low resistivities initially and retain those values on aging, moisture exposure, thermal cycling, and other operating and test conditions. The resistivities of metal-filled epoxy adhesives can range from... 

It is convenient to compare and select adhesives in terms of their resistivities because these values reduce resistance measurements to a common denominator. Volume resistivity, which is the ohmic resistance of a cube of bulk material 1 cm per side, is frequently used to compare the electrical properties of both electrically conductive and electrically insulative adhesives. 

Dispensible electrically insulative adhesive 20 0% epoxy resin, 10-20% epoxy resin modifier, 15% amine, and >50% silica filler Ablebond 84-3 (Henkel)... 

Of the mass-transfer dispensing methods, screen printing and stencil printing are the oldest and most widely used. Screen printing has been used for over 40 years in the electronics industry to apply thick-film conductors, resistors, and dielectrics in fabricating circuits on ceramic and plastic-laminate substrates. Screen printing is also used as a batch process for depositing electrically conductive and insulative adhesives to interconnect devices on thin-film and thick-film hybrid microcircuits. 

In this approach, entire wafers or segments of wafers containing ICs are stacked. Interconnections are formed from vias in the silicon. In vertically stacking memory chips or other IC chips, the chips are first thinned to several mils (4 mils or less), then adhesive bonded, and electrically interconnected directly from chip-to-chip, either from the edges or through vias in the silicon. In these approaches, both electrically conductive and electrically insulative adhesives are used. Thermally conductive preform adhesives or thin thermoplastic films are used to bond and isolate the chips within the stack and to dissipate heat. Several processes are available to vertically stack and interconnect chips of the same size and function such as SRAM, flash, and DRAM memory chips. Other processes have been developed to vertically stack chips of different sizes and functions, or to horizontally interconnect different chips in one layer, then vertically stack the layers. ... 

In packaging imaging sensors at the wafer level (Wafer Level Packaging), insulative adhesive in the shape of window firames are screen printed or otherwise simultaneously applied around all the devices on the wafer, a glass wafer is then attached, and the individual packaged die are singulated." ... 

Thermal conductivity requirements are specified in both military and industry specifications generally as 1.5 W/m K or greater for electrically conductive adhesives and 0.15 W/mK or greater for electrically insulative adhesives. 

The total ionic content and the amounts of specific metal ions such as sodium and potassium greatly affect the electrical properties of an insulative adhesive and of the electronic function of a circuit. A simple test to determine the total ionic content of a polymeric material is to digest a weighed, powdered sample in deionized water and to measure the resistivity of the water extracts after refluxing for 20 hours. This test gives a rough idea of the extent of ionic contaminants in the sample. For example, a drop in resistivity from 10 MQ-cm to 10,000 Q-cm indicates a considerable amount of ionic species. The total ionic content is reported as ppm of equivalent NaCl ... 

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