Combination finish

Plywood furniture core panels, also about 19 mm (3/4 in.) thick, were normally made of a number of layers of relatively thick, 1.5—3.0 mm (1 /16—1 /8 in.) lower value wood veneers combined with thin surface pHes of the decorative veneer. These assembhes were laid-up from glued veneers and then pressed while the bonding occurred. Both lumber core and plywood core have been almost totally displaced in recent years by particleboard or medium-density fiberboard, both discussed herein. This change resulted from the increasing availabiHty and improved finishing characteristics of composites and from decreasing suppHes of core lumber or veneer of suitable quaHty. 

Steel Shot and Grit. Steel shot and grit are also widely used ia grit blasting and abrasive finishing. In 1989, 220, 196 metric tons of metallic abrasives were produced in the United States with a combined value of 89.55 million (20). 

THPC—Amide Process. The THPC—amide process is the first practical process based on THPC. It consists of a combination of THPC, TMM, and urea. In this process, there is the potential of polymer formation by THPC, melamine, and urea. There may also be some limited cross-linking between cellulose and the TMM system. The formulation also includes triethanolamine [102-71-6J, an acid scavenger, which slows polymerization at room temperature. Urea and triethanolamine react with the hydrochloric acid produced in the polymerization reaction, thus preventing acid damage to the fabric. This finish with suitable add-on passes the standard vertical flame test after repeated laundering (80). 

In this case, the components are mixed, the pH adjusted to about 6.0 with sodium hydroxide, and the solution appHed to the textile via a pad-dry-cure treatment. The combination of urea and formaldehyde given off from the THPC further strengthens the polymer and causes a limited amount of cross-linking to the fabric. The Na2HP04 not only acts as a catalyst, but also as an additional buffer for the system. Other weak bases also have been found to be effective. The presence of urea in any flame-retardant finish tends to reduce the amount of formaldehyde released during finishing. 

As previously noted, the APO system leads to fabrics which combine flame resistance and durable press properties however, the toxicity of the aziridinyl system precludes its use in modem textile finishing. 

THPOH—Ammonia—Tris Finish. By far the most effective finish for polyester—cotton textiles was a system based on the THPOH—NH treatment of the cotton component either foUowed or preceded by the appUcation of Tris finish to the polyester component. This combined treatment appeared to be effective on almost any polyester—cotton blend. A large amount of fabric treated in this way was sold throughout the United States and much of the rest of the world. Shortly after the introduction of Tris finishing, Tris was found to be a carcinogen. Most of the Tris treated production was in children s sleepwear, and this created a situation in which almost aU chemical fire-retardant-treated textiles were unfairly condemned as dangerous. Manufacturers mshed to replace chemically treated textiles with products produced from inherently flame-resistant fibers. Nowhere was the impact more severe than in the children s sleepwear market. New, safer materials have been introduced to replace Tris. Thus far none has been as completely effective. 

Phosphonium Salt—Urea Precondensate. A combination approach for producing flame-retardant cotton-synthetic blends has been developed based on the use of a phosphonium salt—urea precondensate (145). The precondensate is appUed to the blend fabric from aqueous solution. The fabric is dried, cured with ammonia gas, and then oxidized. This forms a flame-resistant polymer on and in the cotton fibers of the component. The synthetic component is then treated with either a cycUc phosphonate ester such as Antiblaze 19/ 19T, or hexabromocyclododecane. The result is a blended textile with good flame resistance. Another patent has appeared in which various modifications of the original process have been claimed (146). Although a few finishers have begun to use this process on blended textiles, it is too early to judge its impact on the industry. 

The flavor chemist is responsible for the basic knowledge of sensory and appHcation properties of each of this large number of raw materials the large number of possible combinations of these items to produce specifically flavored finished compounds is readily apparent. It is not uncommon to develop a flavor that combines essential oils, plant extractive, fmit juices, and synthetics. The choice of materials depends on type of product, conditions of manufacture, labeling, and intended use. 

In the compounding technique, constituents are selected or rejected because of their odor, taste, and physical chemical properties, eg, boiling point, solubihty, and chemical reactivity, as weU as the results of flavor tests in water, symp, milk, or an appropriate medium. A compound considered to be characteristic is then combined with other ingredients into a flavor and tested as a finished flavor in the final product by an appHcations laboratory. 

In contrast to dyes, fluorescent whiteners are not appHed exclusively in special processes, but often in combination with bleaching and finishing steps. Fluorescent whiteners used in such processes must be stable and should not interfere with the operation. 

Whitening in combination with the finishing process is used primarily for woven fabrics of ceUulosic fibers and their blends with synthetic fibers. 

Additives. Because of their versatility, imparted via chemical modification, the appHcations of ethyleneimine encompass the entire additive sector. The addition of PEI to PVC plastisols increases the adhesion of the coatings by selective adsorption at the substrate surface (410). PEI derivatives are also used as adhesion promoters in paper coating (411). The adducts formed from fatty alcohol epoxides and PEI are used as dispersants and emulsifiers (412). They are able to control the viscosity of dispersions, and thus faciHtate transport in pipe systems (413). Eatty acid derivatives of PEI are even able to control the viscosity of pigment dispersions (414). The high nitrogen content of PEIs has a flame-retardant effect. This property is used, in combination with phosphoms compounds, for providing wood panels (415), ceUulose (416), or polymer blends (417,418) with a flame-retardant finish. 

Textile Finishing. Polyethyleneimine-A/-methylolurea derivatives improve the crease and wear resistance of cotton (429,430). The adhesion between individual wool fibers is improved by pretreatment with amines, which leads to improved shrink resistance (431). An antimicrobial finish can be appHed to cotton by using a combination of PEI and ureas to bind zinc pyrithione to the fabric (432). After wool has been provided with a flameproof finish using fluorozirconate or fluorotitanate, the wool can be neutralized with PEI (433). Conventional neutralizing agents caimot be used for this purpose since they impair the flameproof characteristics of the impregnated fabric. 

Corrosion and Finishing. With few exceptions, magnesium exhibits good resistance to corrosion at normal ambient temperatures unless there is significant water content ia the environment ia combination with certain contaminants. The reaction which typically occurs is described by the equation... 

Extreme caution must be taken to prevent the possibility of fire when using flammable removers. Extra care must be taken when stripping on location to secure the area of ignition sources. When used on lacquer finishes, the dissolved finish and remover combined are extremely flammable. Natural mbber, neoprene, or other gloves suitable for use with the remover formula must be worn. The effect of skin contact with the remover is limited because there is immediate irritation and discomfort. Canister respirators are available for most petroleum and oxygenate remover solvents. Symptoms of long-term overexposure should be compared to symptoms of the major ingredients in the formula. 

The wide range of types of paper products results in a variety of sludges. SoHd wastes result from several sources within the mill, eg, bark, sawdust, dirt, knots, pulpwood rejects, flyash, cinders, slag, and sludges. Sludges often are disposed of in combination with residuals from other sources. Approximately 300 kg of soHd waste per ton of finished product is generated by the pulp and paper industry. 

---