Tape adhesives

Fig. XII-15. Diagram of peel test. A and B, adhesive joint C, double Scotch adhesive tape and D, rigid support. (From Ref. 107. By permission of IBC Business Press, Ltd.)...

Cellulosics. CeUulosic adhesives are obtained by modification of cellulose [9004-34-6] (qv) which comes from cotton linters and wood pulp. Cellulose can be nitrated to provide cellulose nitrate [9004-70-0] which is soluble in organic solvents. When cellulose nitrate is dissolved in amyl acetate [628-63-7] for example, a general purpose solvent-based adhesive which is both waterproof and flexible is formed. Cellulose esterification leads to materials such as cellulose acetate [9004-35-7], which has been used as a pressure-sensitive adhesive tape backing. Cellulose can also be ethoxylated, providing hydroxyethylceUulose which is useful as a thickening agent for poly(vinyl acetate) emulsion adhesives. Etherification leads to materials such as methylceUulose [9004-67-5] which are soluble in water and can be modified with glyceral [56-81-5] to produce adhesives used as wallpaper paste (see Cellulose esters Cellulose ethers). 

Other important properties that can be measured in the laboratory include sealabiHty, printabiHty, or coating adhesion. Many of these tests have been developed by the film manufacturer in cooperation with customers and are specifically designed to measure product performance in the end use. Some tests, like sealabiHty, can be standardi2ed to time, pressure, and temperature of sealing with instmment-measured peel values, but other tests are subjective, such as evaluations of printing loss to puUoff by adhesive tape. 

The aerodynamic wheel cover of claim 1 wherein said adhesive means comprises an adhesive selected from the group consisting of velcro, adhesive tape, or an adhesive resin. 

Adhesive tapes (electron-beam-cured adhesives)... 

Carton sealing is carried out automatically by adhesives, tape, or staples or manually by tape or staples. Carton closer-sealers have... 

A number of higher poly(vinyl ether)s, in particular the ethyl and butyl polymers, have found use as adhesives. When antioxidants are incorporated, pressure-sensitive adhesive tapes from poly(vinyl ethyl ether) are said to have twice the shelf life of similar tapes from natural rubber. Copolymers of vinyl isobutyl ether with methyl acrylate and ethyl acrylate (Acronal series) and with vinyl chloride have been commercially marketed. The first two products have been used as adhesives and impregnating agents for textile, paper and leather whilst the latter (Vinoflex MP 400) has found use in surface coatings. 

The rubbers are also used for such diverse applications as blood transfusion tubing capable of sterilisation, antibiotic container closures, electric iron gaskets, domestic refrigerators and non-adhesive rubber-covered rollers for handling such materials as confectionery and adhesive tape. The cold-curing rubbers are of value in potting and encapsulation. 

Instead of using a single layer of adhesive, tapes with two layers of adhesive, which can be of the same or different type, have also been constructed. Here, a thin film backing may be used as the central layer of the tape, with the adhesives coated on each side of the backing. This type of tape construction is commonly referred to as a double-stick or double-faced tape. 

Glossary of Terms. Test Methods for Pressure Sensitive Adhesive Tapes, Pressure Sensitive Tape Council, 1996. 

Gierenz, G. and Karmann, W., Adhesives and Adhesive Tapes. Wiley-VCH, New York, 2001. 

In situations in which piping protrudes partitions or bulkheads of dissimilar metals, proper precautions should be taken against galvanic corrosion. Possible solutions include the use of dielectric gaskets or sleeves and the use of plastic adhesive tapes. Examples are illustrated in Figure 2.6. 

Some items, such as electrolytic capacitors and two-part adhesives, may deteriorate when dormant. Others, such as rubber, adhesive tape, and chemicals, deteriorate with the passage of time regardless of use. These are often referred to as Shelf Life Items or Limited Life Items . Dormant electronic assemblies can deteriorate in storage and provision should be made to retest equipment periodically or prior to release if in storage for more than one year. 

Kleb-, Klebe-. adhesive, adherent, sticking. Kleb-ather, m. collodion, -band, n. adhesive tape. 

KleberoUe, /. (roll of) gummed tape or adhesive tape. 

Kleberschicht, /. Boi.) aleurone layer. Klebe-stoff, m. adhesive substance, cement adhesive binder, -streifen, m. adhesive tape, -taffet, m. court plaster, -wachs, n. acUiesive wax, sticking wax. -zettel, m. gummed label, sticker, klebfahig, a. adhesive. 

For instance, in 1996, 3M company announced a breakthrough in the process for making medical adhesive tapes, a process that reduces energy consumption by 77 percent. The new process also cuts solvent use by 2.4 million pounds, lowers manufacturing costs, and cuts mannfacturing cycle time by 25 percent. The proprietary process took researchers nine years from conception through final implementation. 

Pipework should be easily identifiable in accordance with BS 1719. Where the normal pressure in the pipe exceeds 75mbar, consideration should be given to labeling the pipe with the normal operating pressure. In buildings in which there are no other piped flammable gas supplies it is sufficient to paint the pipe yellow ochre or to band it with appropriately colored adhesive tape. In large complex installations, it is desirable to identify pipe contents more precisely, and in those instances, the base color should be supplemented with a secondary code band of yellow and/or its name or chemical symbol. 

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. 

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. 

A method of evaluating the adhesive bond to a plastic coating substrate is a tape test. Pressure-sensitive adhesive tape is applied to an area of the adhesive coating, which is... 

An adhesive tape for photographic films can be made by using a coating containing a water- or alkali-soluble polymer and ether carboxylate [211]. A light-sensitive resin composition with ether carboxylic acid salt for flexographic plate material shows an improved flexibility and solvent resistance [212]. 

Note The iodine evaporates relatively quickly from the layer after a chromatogram has been removed from the iodine chamber. This evaporation of the iodine can be considerably delayed by covering the chromatogram with a glass plate the edge can also be sealed with adhesive tape, if necessary. Iodine solution can also be used for detection instead of iodine vapor. 

Table 8.24 compares SS-ZGFAAS results for product control of Cd in automotive polymers with conventional methods [141]. SS-ZAAS was also used for QC purposes to determine Cu, Mn, Fe, Cd and Pb in adhesive tapes [144],... 

Rtihl [141] has reported on very large scale SS-GFAAS and XRF analysis of Cd in polymers for product control purposes in the automobile industry (approximately 20 000 parts per year) as a reaction on a Swedish law for environmental protection (upper limit of 75ppm). Another sample of direct SS-GFAAS in industry is the control of all raw materials, processing steps, and products for adhesive tapes for the content of Cu, Mn, Fe, Cd and Pb, which act as a rubber poison by catalytic effects [144]. 

---