Crepes

Blanco Directo process Blanc-Quelet reaction Blanket crepes Bla-S... 

Brown crepes Brown dyes Brownian particles Brown oxides... 

Gut Rubber. To produce cut mbber thread, smoked mbber sheet or crepe mbber is milled with vulcanizing agents, stabilizers, and pigments. This milled stock is calendered into sheets 0.3—1.3 mm thickness, depending on the final size of the mbber thread desired. Multiple sheets are layered, heat-treated to vulcanize, then sHt into threads for textile uses (Fig. 2). Individual threads have either square or rectangular cross-sections. 

Other types of dryers may be employed for special products or situations. For example, the Yankee dryer, a steam-heated cylinder, 3.7—6.1 m dia, dries the sheet from one side only. It is used extensively for tissues, particularly where creping is accompHshed as the sheet leaves the dryer, and to produce machine-gla2ed papers where intimate contact with the poHshed dryer surface produces a high gloss finish on the contact side. 

Spray appHcations to the surface of the sheet have been useful, especially for appHcation of creping aids and release agents in towel and tissue miUs. The spray appHcation of functional chemicals has not been used widely. Generally, the uniformity of appHcation is mote difficult to control when functional chemicals are sprayed than when they are appHed by a size press. Eunctional chemicals also can be appHed to heavier grades of paper or paperboard at the calender stack. 

Application of Wet-Strength Resins. Wet-strength resins seldom are appHed to the surface of paper for enhancing wet strength because the commercially available, cationic wet-strength resins are retained so effectively internally. However, wet-strength resins are appHed frequendy to the surface of towels and tissues as creping aids. 

For increased solubiHty to prevent bloom, shorter-chain carboxyHc acids or zinc carboxylates can be substituted. The use of chain-branched carboxyHc acids reduces the tendency for the formulations to lose sulfur cross-links or revert upon prolonged heating (7). Translucent articles such as crepe soles can use a zinc carboxylate or employ zinc carbonate as a transparent zinc oxide. 

Fig. 1. Routes by which natural rubber latex is converted into traditional sheet and crepe.

Pa.le Crepes. Sri Lanka is the largest producer of crepe mbber, as either thin pale crepe or thick pale crepe, which accounts for 35% of mbber production. Pale crepes are divided into one of three classes, depending on the manufacturing process (11,12) fractionated and bleached mbber (FB) unfractionated, but bleached mbber (UFB) or yellow fraction mbber (YF). 

Crumb/block Sheet/crepe rubber rubber... 

The reversible addition of sodium bisulfite to carbonyl groups is used ia the purification of aldehydes. Sodium bisulfite also is employed ia polymer and synthetic fiber manufacture ia several ways. In free-radical polymerization of vinyl and diene monomers, sodium bisulfite or metabisulfite is frequentiy used as the reduciag component of a so-called redox initiator (see Initiators). Sodium bisulfite is also used as a color preventative and is added as such during the coagulation of crepe mbber. 

Paper may also be colored by surface appHcation of dyestuff solutions after the paper has been formed and dried or partially dried by utilizing size-press addition, calendar staining, or coating operations on the paper machine. In addition, paper may be colored in off-machine processes by dip dyeings or absorption of dyestuff solution and subsequent drying, such as for decorative crepe papers. 

Comminuted and other new process rubbers. In these cases the coagulum is broken up and then dried. The rubber is then packed in flat bales similar in size to those used for the major synthetic rubbers (70-75 lb) unlike the heavier square bales used with smoked sheet and crepe rubbers. 

Whilst, chemically, SBS triblocks are similar to SBR, for example they do not show measurable breakdown on mastication, they are seriously deficient in one respect, they show a high level of creep. This would indicate that the concept of all the styrene blocks being embedded in the domains with all of the polybutadiene blocks being in the amorphous matrix is rather too simplistic. It has also resulted in these materials not being used extensively in traditional rubber applications. One exception from this is in footwear, where blends of SBS and polystyrene have been used with noted success for crepe soles. 

In solid form, the natural rubber is graded according to the content of dirt remaining from the precipitation of latex at the plantation. Eight basic NR types have been traditionally recognized internationally. Only the so-called ribbed smoked sheets and the pale crepes are normally used for adhesives. The predominant grade system, the Standard Malaysian Rubber system, has been used since 1965. 

Heveaplus MG has a higher polarity than NR and it is usually used as primer for NR solutions to increase the adhesion of PVC and synthetic upper materials in crepe rubber soles in footwear. 

Various sponges microcellular sponge, hard sponge, semihard sponge, soft sponge, crepe-tone sponge... 

Cremor tsrtaru cream of tartar. Cr pekautschuk, m. n. crepe rubber. Cresylaaure,/. cresylic acid (cresol). 

Rubber is a polymer of isoprene (15). Natural rubber is obtained from the bark of the rubber tree as a milky white liquid, which is called latex (Fig. 19.8) and consists of a suspension of rubber particles in water. The rubber itself is a soft white solid that becomes even softer when warm. It is used for pencil erasers and was once used as crepe rubber for the soles of shoes. 

Oxidation of Natural Rubber (NR) Pale Crepe at 46°C, Accelerated by Ultraviolet (UV) Light... 

Cherries Jubilee, Bananas Foster, Crepes Suzette, Beef Flambe, Steak au Poivre—all are recipes that use a dramatic procedure of flaming a liqueur to introduce additional flavors into the preparation. A little knowledge of chemistry will ensure that your concoction is a delicious one ... 

A grade of natural rubber inferior to estate brown crepe and formerly known as thick remilled brown crepe cuttings removed in the inspection of smoked sheet rubber are washed, creped and designated smoked blanket crepe . 

A substance added to latex in the preparation of pale crepe rubber sodium bisulphate prevents darkening of the crepe due to the presence of oxidising enzymes, xylyl mercaptan is an effective bleaching agent proper. 

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