Flocking process

Table 3.4 summarizes the consumption of thermosetting binders used in various regions. The epoxy-polyester systems predominate over polyester-trisglycidyl iso-cyanurate and epoxy systems. The consumption of thermoplastic coating powders, particularly those used in the fluidized-bed and flocking processes, is substantially lower than that of thermosetting powders (Table 3.5). Their production does not show a comparably significant growth rate.

The purpose of this phase of the research was to evaluate practical uses of the textile wastes in various products involving the textile flocking process. In this regard, consideration was given to evaluating flock fibers fabricated from textile wastes of fiber mixtures in various applications. Several questions were posed by this initial smdy ... 

The flocking process begins with the bonding of cnt fibers to an adhesive-coated fabric to obtain a decorative and fnnctional material (215). Acrylics can provide the softness and durability that are sought in flocked textiles they also serve as binders for pigments in the printing of flocked fabrics (35,216,217). 

Because the adhesive represents the positive pole (earth) in the electrostatic flocking process, through which the charge must be dissipated rapidly, it is required to show a certain conductivity (maximum resistance 10 Q) This is not a problem where water-based adhesives are used, but in the case of solvent-containing adhesives, the necessary conductivity often can be obtained only by means of additives. 

Combinations of two or more of the above steps into consecutive processes, such as spin—draw or spin—draw—texture, reduces manufacturing costs. In addition to continuous-fHament yam, nylon is also offered in staple, tow, and flock forms. Staple is made by cutting crimped continuous-fHament yam into 3—20-cm lengths. In manufacturing, tow is made by combining many yam ends, either flat or crimped, to give a total tow size of 6—111 ktex. 

Alum Astringent crystalline double sulfate of an alkali. K2SO4AL2 (S04)j 24H2O. Used in the processing of pickles and as a flocking agent. Excess aluminum in the environment can be hazardous. 

Plastic, virgin A plastic material in the form of pellets, granules, powder, flock, liquid, etc. that has not been subjected to use or processing other than what was required for its initial manufacture. It is not recycled plastics. 

Depending on process parameters, culture age and genetic make-up, filamentous microorganisms in an industrial fermenter can either grow as free mycelia or as mycelial aggregates — pellets or flocks (Fig. 2). Of course, this polar definition is far from reality all kinds of intermediate morphologies exist between free unassociated mycelia, loose flocks and dense pellets. The... 

Precipitation polymerization, also called slurry polymerization, is a variety of solution polymerization where the monomer is soluble but the polymer precipitates as a fine flock. The formation of olefin polymers via coordination polymerization occurs by a slurry process. Here, the catalyst is prepared and polymerization is carried out under pressure and at low temperatures, generally less than 100°C. The polymer forms viscous slurries. Care is taken so that the polymer does not cake up on the sides and stirrer. 

Although the use of membrane reactors for the retention of the enzyme is mostly applied in continuous processes, some authors used a membrane batch reactor in order to reuse the enzyme in consecutive cycles [11, 74]. Flock et al. used a membrane unit coupled to the reactor with recycling of both permeate and retentate streams to the reactor vessel. A valve at the outlet of the membrane maintained pressure within the range fixed by the manufacturer [74]. Pasta et al. operated a reactor with the membrane inside, emptied the reactor content at scheduled times, and thereafter, replenished it with fresh solution of the substrate and the oxidizing system [11]. 

There are different types of plastics that are usually identified by their composition and/or performance. As an example there are virgin plastics. They are plastic materials that have not been subjected to any fabricating process. NEAT polymers identify plastics with Nothing Else Added To. They are true virgin polymers since they do not contain additives, fillers, etc. They are very rarely used. Plastic materials to be processed are in the form of pellets, granules, flakes, powders, flocks, liquids, etc. Of the 35,000 types available worldwide there are about 200 basic types or families that are commercially recognized with less than 20 that are popularly used. Examples of these plastics are shown in Table 1.1. 

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