Self-adhesion

Constrained-Layer Treatments. Constrained-layer damping treatments consist of a thin layer (/ m) of viscoelastic material sandwiched between a base material and an outer constraining layer of sheet metal or other stmctural material. Some of these treatments are available with self-adhesives on both sides of the viscoelastic material and act as a bonding agent between the base and constraining layers others have the constraining layer already bonded to the inner layer so they need only be appHed to the base material. 

This stock is discharged from the mixer to equipment that allows cooling and a convenient storage form, such as a mill or an extmder/die plate that yields a sheet or pelletized form. Usually the material is coated with a slurry of clay, calcium carbonate, or zinc stearate to prevent self-adhesion. 

Mamzen Oil Co. has developed various Ziegler-Natta catalysts that can produce poly(butadiene-i //-prop5iene) (PBR) (78). PBR shows tack (self-adhesion) and green (unvulcanized) dynamic properties superior to those of BR and EPDM. Carbon black-loaded vulcanizates can be compounded to give high strength and elongation at break (79,80). PBR can also be covulcanized with SBR, BR, and EPDM. 

Interesting products may also be produced by introducing boron atoms into the chain. The amount of boron used is usualy small (B Si 1 500 to 1 200) but its presence increases the self-adhesive tack of the rubber, which is desirable where hand-building operations are involved. The products may be obtained by condensing dialkylpolysiloxanes end-blocked with silanol groups with boric acid, or by reacting ethoxyl end-blocked polymers with boron triacetate. 

Ruths and Granick [95] have studied the self-adhesion of several monolayers and adsorbed polymers onto mica. For loose-packed monolayers, the adhesion, in excess of a constant value observed at low rate, increased as a power law with the square root of the separation rate. In the case of adsorbed diblocks, the excess adhesion increased linearly with logarithmic separation rate. The time effects were ascribed to interdigitation and interdiffusion between the contacting layers. 

Excellent tack. Solvent solutions are very tacky even without addition of a resin. Latex compounds exhibit superior self-adhesion after coated surfaces have dried. 

The use of coatings applied in the form of tape is also increasing. Polyethylene and polyvinyl chloride films, either self adhesive or else supporting films of butyl adhesive, petrolatum or butyl mastic are in use as materials applied cold at ambient temperatures. Woven glass fibre or nylon bandage is also used to support films of filled asphalt or coal tar and these are softened by propane gas torches and applied to the steel surface hot, cooling to form a thick conforming adherent layer. 

Spiral corrosion due to inadequate overlap has been detected with self-adhesive tapes, and a 25 mm (or preferably half-tape-width) overlap is to be advocated. Within normal limits, the thicker the adhesive the better. 

The self-adhesive tape coatings are thin and the adhesive itself does not necessarily come into contact with the valleys in the cleaned metal surface. Under these circumstances, the transmission of water vapour through the film to the metal may be possible. Moisture-transmission characteristics and other properties of p.v.c. and polyethylene tapes, as given by major manufacturers, are provided in Table 14.6. 

Table 14.6 is only indicative of general properties, and the latest developments of specific manufacturers of self-adhesive tapes may show advances on these. 

Weld joints may be coated in the field with FBE powder, utilising a portable blast cleaning/induction heating and powder application system. Alternatively joints may be provided with self-adhesive laminate tapes or heat-shrink crosslinked polyethylene sleeves. 

Repairs to the coating are made with either hot-melt polyethylene sticks or polyethylene sheet patches with mastic profiling compounds for small damaged areas. Large repair areas are best treated as for field weld joint coating, where either heat-shrink crosslinked polyethylene sleeves or cold-applied self-adhesive laminate tapes are employed. 

In addition to the petrolatum tapes and those based on a laminate of p.e. or p.v.c. with an elastomeric sealant or pressure-sensitive adhesive layer, recent developments have centred around self-adhesive bituminous laminates. These tapes are commonly constructed with a p.v.c. backing, whose thickness ranges from 0 08 to 0 75 mm and a bituminous adhesive compound layer to provide a total tape thickness of up to 2 mm. In order to maintain conformability without compromising impact values, tapes may also be manufactured with a fabric reinforcement within the bituminous layer. 

The monitoring of temperatures for electronic control systems is now mainly by thermocouples, secured onto the outside of the pipe with self-adhesive tape and the pipe then insulated over. 

These are usually self-adhesive, precut, printed patterns on a substrate that are simply adhered to the surface of a product. Decals generally use a transparent plastic film while labels are usually on an opaque plastic, metallic and multilayer sandwich base. Labels of sufficient thickness are useful for hiding unavoidable appearance problems such as gate and sprue removal areas, sink marks, blushes, splays, and weld lines. 

Promote improved elasticity and cold temperature flexibility. Used in cables, self-adhesive products, roadmarking materials, etc. 

Strip packages represent an alternative form of packaging for unit-dose medication. Strips can be produced from single- or multiple-ply laminated materials provided the two inner plies can be sealed by heat or pressure (e.g., cold self-adhesive seals). Materials can range from relatively permeable plies to those that incorporate a foil ply of sufficient thickness and effectiveness of seal so that an individual hermetic seal is produced for each dosage. Strip packages are produced at lower speeds and occupy greater volume than blisters. 

How Do Repositional Self-Adhesive Paper Notepad Sheets (Post-it Notes) Work ... 

M9 Chemical Detection Paper A self-adhesive paper that can be readily attached to the body or to vehicles, shelters, and other equipment. It cannot distinguish the identity of agents. The agent sensitive dye will turn red upon contact with liquid nerve agents (G and V) and blister agents (H and L). The paper produces colored spots when in contact with nerve and blister agents. 

DRESSING CHEST WOUND ONE WAY VALVE SELF ADHESIVE KRATON 10/PG 6510014081920 PG 74,67 ... 

In-mould labelling (IML) used for injection-moulded products and blow-moulded bottles is an alternative to self-adhesive or heat-transfer decoration, eliminating a finishing step. 

As previously stated, the rigid polyimides meet many of the requirements for microelectronics applications however, the presence of an ordered morphology, coupled with the lack of a softening transition results in extremely poor self-adhesion. Alternatively, thermally stable thermoplastics exhibit excellent self-adhesion, but often lack sufficiently high temperature dimensional stability and/or solubility and processability from common organic solvents. For instance, po-ly(phenylquinoxaline) (PPQ) has a T in the 370 °C range, thereby overcoming... 

Combined hormone replacement therapy is also available as self-adhesive patches and creams. 

Airofom PA 230 is a non-crosslinked PE foam which while having a slightly lower temperature resistance than crosslinked types, is claimed to be substantially cheaper to process. It has a closed-cell structure and is available in rolls, sheets and fabricated products, or as a self-adhesive backed or laminated to other materials. A sample of the foam is included. 

Examples are given of the use of extruded PE foam sections in conjunction with other polymeric materials in the production of triangular, semicircular, rectangular and trapezoidal profiles, e.g. beam-like structures in which the rigid support may be of GRP. The foam can be bonded with thermally-fusible adhesives or two-sided self adhesive tape affixed to the foam prior to fabricating. A standard range of the foam prodncts is available, but other types can be tailor-made. 

Accutane must be prescribed under the System to Manage Accutane-Related Teratogenicity (SMART). The prescriber must obtain a supply of yellow self-adhesive Accutane qualification stickers. To obtain these stickers 1) Read the booklet entitled SMART Guide to Best Practices] 2) sign and return the completed SMART letter of understanding containing the prescriber checklist and 3) use the yellow self-adhesive Accutane qualification sticker. Accutane should not be prescribed or dispensed to any patient (male or female) without a yellow self-adhesive Accutane qualification sticker. 

Female patients For female patients, the yellow self-adhesive Accutane qualification sticker signifies that she understands the following ... 

The yellow self-adhesive Accutane qualification sticker documents that the female patient is qualified and includes the date of qualification, patient gender, cut-off date for filling the prescription, and up to a 30-day supply limit with no refills. 

Isotretinoin should be prescribed only by prescribers who have demonstrated special competence in the diagnosis and treatment of severe recalcitrant nodular acne, are experienced in the use of systemic retinoids, have read the SMART Guide to Best Practices, signed and returned the completed SMART letter of understanding, and obtained yellow self-adhesive Accutane qualification stickers. Do not prescribe or dispense Accutane without a yellow self-adhesive Accutane qualification sticker. 

Male patients These yellow self-adhesive Accutane qualification stickers also should be used for male patients. 

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