Use in paper

Used industrially to cross-link hydroxylic polymers, polyethyleneimine. Possesses some carcinogenic properties. Polyethyleneimine is a hygroscopic liquid used in paper manufacture to confer wet strength and in textiles, alkylated derivatives also form useful polymers. 

The AKDs are used in paper sizing appHcations. Paper sizing chemicals provide paper and paperboard with resistance to wetting by Hquids, especially water repeUency in paper cups, milk cartons, photographic paper, coatings, and packaging paper (139) (see Paper Papermaking additives). 

Alkenylsuccinic anhydrides made from several linear alpha olefins are used in paper sizing, detergents, and other uses. Sulfosuccinic acid esters serve as surface active agents. Alkyd resins (qv) are used as surface coatings. Chlorendric anhydride [115-27-5] is used as a flame resistant component (see Flame retardants). Tetrahydrophthalic acid [88-98-2] and hexahydrophthalic anhydride [85-42-7] have specialty resin appHcations. Gas barrier films made by grafting maleic anhydride to polypropylene [25085-53-4] film are used in food packaging (qv). Poly(maleic anhydride) [24937-72-2] is used as a scale preventer and corrosion inhibitor (see Corrosion and corrosion control). Maleic anhydride forms copolymers with ethylene glycol methyl vinyl ethers which are partially esterified for biomedical and pharmaceutical uses (189) (see Pharmaceuticals). 

Use of mercury and mercury compounds for agricultural purposes was banned by the EPA in 1978, and use in paper and pulp is beUeved to have been discontinued. 

In addition, many grades of paper and paperboard are used in direct or indirect contact with foods. Thus, many mills only use paper chemicals that have been cleared for use by the U.S. Pood and Dmg Administration (PDA) (3), so that it is not necessary to segregate machine broke (off-grade paper and edge clippings that are reclaimed for their fiber value) and white water. Most of the chemicals discussed in this article are approved by the PDA for use in paper and paperboard that are intended for appHcations in food processing and packaging. However, there are various restrictions on both the specific functional uses and amounts of paper chemical additives which can be used, so the PDA status should be confirmed by the suppHer before use. 

The defoamer formulations mentioned so far consist of fairly inexpensive raw materials, but several more cosdy defoaming materials have come into use in paper mills. Hydrophobicized siUca particles are useful in some emulsion formulations. SiUcone solutions and emulsions are very effective in eliminating foam in paper machine water systems. The siUca- or siUcone-based defoamers have higher activity, which somewhat compensates for the higher cost, but care must be taken to prevent ovemse. 

Other. A large variety of additives are used in paper-coatiag colors primarily to modify the physical properties of the colors (102). At high soHds concentrations in water, mineral pigment particles tend to associate and form viscous pastes. Dispersants (qv) are used to prevent this and to provide low viscosity slurries. Common dispersants include polyphosphates and sodium polyacrylate [9003-04-7]. Various water-soluble polymers are added to coatiag colors and act as water-retention agents and as rheology modifiers. 

Melamine—formaldehyde resins may be used in paper which contacts aqueous and fatty foods according to 21 CFR 121.181.30. However, because a lower PEL has been estabUshed by OSHA, some mills are looking for alternatives. Approaches toward achieving lower formaldehyde levels in the resins have been reported (66,67) the efficacy of these systems needs to be estabUshed. Although alternative resins are available, significant changes in the papermaking operation would be required in order for them to be used effectively. 

This growth will substantially increase demand for surfactants, bleaching agents, complexing agents, and other chemicals used in paper recycling... 

A more permanent installation is provided by a chain-driven sampler, widely used in paper (qv) and steel (qv) mills, manufactured as the E Sampler by QCEC (20). A cup, which is attached to a chain positioned perpendicular to flow, travels down through the Hquid flow and returns to the upper sprocket, where the sample is drained into a container. Flow-proportional timers can be installed to change the rate of sampling with flow rate (see Flow l asurel nt). 

Oxidized starches, usually those prepared by hypochlorite oxidation, ate used in paper coatings and adhesives (qv) to improved surface characteristics for printing or writing. Oxidized starches may also be employed as textile warp sizes and finishes, in manufacture of insulation and... 

Dibutyltin and dioctyltin diacetate, dilaurate, and di-(2-ethylhexanoate) are used as catalysts for the curing of room-temperature-vulcanized (RTV) sihcone elastomers to produce flexible siUcone mbbers used as sealing compounds, insulators, and in a wide variety of other appHcations. Diorganotin carboxylates also catalyze the curing of thermosetting siHcone resins, which are widely used in paper-release coatings. 

Following wet processing, fine particle size kaolins may be calcined, ie, heat treated at about 1000°C. This treatment converts the kaolin to an amorphous pigment of significantly higher brightness and opacity (8). Properties of the various types of kaolins used in paper are shown in Table 2. 

Fiber from PPS resins has been made in two forms. Monofilament is used in paper machine drier felts to replace polyester, which is attacked by the hot, corrosive conditions of papermaking. Staple fibers are made into filter bags for flue treatment, and are considered a growth area. 

Latices of butadiene-methyl methacrylate copolymer have been used in paper and board finishes. 

The 8-aza analogs are formally derived by substitution of the methine group in position 8 of the purine ring. The names thus derived preserve the numbering of the purine ring (146), and are frequently used in papers of biochemical character, but in chemical papers only along with systematic names. 

Bleaching is defined as any process that chemically alters pulp to increase its brightness. Bleached pulps create papers that are whiter, brighter, softer, and more absorbent than unbleached pulps. Bleached pulps are used for white or light colored paper. Unbleached pulp is typically used to produce boxboard, linerboard, and grocery bags. Of the approximately 65.5 million T (72 million tons) of pulp (including recycled pulp) used in paper production in the U.S. in 2000, about 50% is for bleached pulp.1... 

Basics Why is Ti02 Used in Paper Millenium Chemicals, http //www.millenniumchem.com/Products+and+Services/Products+by+Type/ Titanium+Dioxide+-+Paper/r Paper+Basics/... 

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