Lamination cellulose acetate

Barrow, who was developing cellulose acetate lamination as a method of preserving documents, took the step of applying the bicarbonate solutions to the preservation of acid papers, both those still with adequate strength and those weak and requiring lamination. According to Clapp... 

In the Library of Congress collections one can find good and bad examples of the two systems, silking and cellulose acetate lamination. One can only conclude, therefore, that in addition to adequate treatment of the papers before lamination, the craftsman s manipulative techniques of application, (and, with silking, pressing and drying) are fundamental to truly archival protection. 

NARS Specification for Cellulose Acetate Laminating Film. 

Synthetic resins are extensively used, e.g., in surface finishes, in the fabrication and repair of boat and motor vehicle bodies, in the manufacture of laminated boards, for electrical components, in pattern making and in paints and varnishes. Non-rubber adhesives made from fish glues and from cotton derivatives (e.g. cellulose acetate) tend not to be sensitizing but, depending upon composition and the manner of use, many other types may pose significant dermatitic and fume hazards. 

Packaging materials which have a smooth, impervious surface, free fi cm crevices or interstices, such as cellulose acetate, polyethylene, polypropylene, poly vinylchloride, and metal foils and laminates, all have a low surface microbial count. Cardboard and paperboard, unless treated, carry mould spores of Cladosporium spp., Aspergillus spp. md Penicillium spp. and bacteria such 2 Bacillus spp. sn.dMicrococcus spp. 

This safety glass turned yellow after several years of exposure to light. The bonding layer was replaced in 1933 by cellulose acetate, made from the reaction of cotton with acetic acid. By 1939 this was replaced by poly(vinyl butyral) (PVB), which is still in use today as the adhesive placed between sheets of glass to produce laminated safety glass. This is one of a very few modern-use materials that has retained the same basic materials for over 60 years. 

There are four major types of barrier materials used now in the US for military purposes a)Water-proof b)Greaseproof c)Water-vapor-proof and d) Combinations of a,b c. Almost all the barrier materials in use today are composed of several layers or plies. The plies are usually cemented together with suitable adhesives(/< mi anrs) to form a laminated structure, although several other methods of making multi-ply sheets are also used. Materials used for making plies include kraft paper, cotton scrim, aluminum foil, polyethylene, cellulose acetate, Mylar, etc... 

Figure 2.15 Measurements of Rosenbaum and Cotton [20] of the water concentration gradients in a laminated reverse osmosis cellulose acetate membrane under applied pressures of 68 and 136 atm. Reprinted from Steady-state Distribution of Water in Cellulose Acetate Membrane, S. Rosenbaum and O. Cotton, J. Polym. Sci. 7, 101 Copyright 1969. This material is used by permission of John Wiley Sons, Inc.

Membranes and composites from cellulose and cellulose esters are important domains in the development and application of these polymer materials. The most important segment by volume in the chemical processing of cellulose contains regenerated cellulose fibers, films, and membranes, hi the case of the cellulose esters mainly cellulose nitrate and cellulose acetate as well as novel high-performance materials created therefrom are widely used as laminates, composites, optical/photographic films and membranes, or other separation media, as reviewed in [1], The previously specified nanocelluloses from bacteria and wood tie in with these important potentials and open novel fields of application. 

TG-MS is an ideal technique for identifying residual volatiles in polymers. The detection of residual volatiles (and of other impurities) can often yield clues as to manufacturing processes. In many cases, such as in the determination of highly volatile materials, of residual solvents or plasticisers, use of TG-MS is requested. Specifically, there are reports on the entrapment of curing volatiles in bismaleimide laminates [145] and elastomers [48], on the detection of a curing agent (dicumylperoxide) in EPDM rubbers and of bromine flame retardants in electronic waste [50], of plasticisers such as bambuterol hydrochloride [142] or TPP and diethylterephthalate in cellulose acetate [143], on solvent extraction and formaldehyde loss in phenolic resins [164], and on the evolution of toxic compounds from PVC and polyurethane foams [146]. 

Through research sponsored by NARS and other government agencies (at NBS), specifications were developed for a stable laminating film formulated from cellulose acetate (35). Unfortunately, these specifications never were processed through a standards organization. 

A spirothietane sulfone-oxetane is a comonomer in the preparation of polyethers. A polymer obtained from this sulfone in a solution of bis(3,3-chloromethyl) oxetane with phosphorus pentafluoride can be spun to drawable filaments. Thietane sulfone spirocyclic carbonates may be polymerized via the carbonate group to high-molecular-weight solids said to be useful in laminating. Thietane 1,1-dioxide improves the dye receptivity of poly (acrylonitrile), viscose, cellulose acetate, and poly(vinyl chloride). It is also reported to be a stabilizer for nitric acid in oxidizer mixtures for rocket motors. 2-Methylthietane 1,1-dioxide is claimed to be superior to sulfolane (thiolane 1,1-dioxide) in the liquid extraction of aromatic hydrocarbons from mixtures with saturated hydrocarbons. " A number of bis(3,3-alkoxy) thietane 1,1-dioxides have been proposed as intermediates in the preparation of cyanine dyes useful as photographic sensitizers. " ... 

The first composite reverse osmosis membrane reported in the technical literature was developed by Peter Francis of North Star Research Institute in 1964 (4). This membrane was formed by float-casting an ultrathin film of cellulose acetate (CA) upon a water surface, removing the membrane from the water surface by lamination onto a pre-formed microporous support film and drying to bond the membrane to the support. This float-casting procedure has since been described in the technical literature for both flat sheet and tubular membranes ( 5, 6, T). 

Virtually the entire membrane manufacture today is based on laminate structures comprising a thin barrier layer deployed upon a much thicker, highly permeable support. Most are formed of compositionaUy homogeneous polysulfone, cellulose acetate, polyamides, and various fluoropolymers by phase inversion techniques in which ultrathin films of suitably permselective material are deposited on prefabricated porous support structures. Hydrophobic polymers as polyethylene, polypropylene, or polysulfone are often used as supports. A fairly comprehensive hst of microporous and ultrafiltration commercial membranes and produced companies are presented in Refs [107-109]. A review on inorganic membranes has been given in Ref. [110]. 

If colour is very strong, litho in thin layers is not so rub-resistant as letterpress because of low varnish level. Note that rub resistance and brightness can usually be improved by the addition of over-lacquers or varnishes (based on shellac (spirit), nitrocellulose, Saran, vinyl, epoxy, water varnishes, etc.) or lamination (cellulose acetate, polypropylene, PVC, etc.). Coatings or laminations may also provide heat sealability. 

Sterile filtration of liquids and gases is now virtually always done using mem brane filters. The first U.S. patent for membrane filters was filed in 1922 and pertained to cellulose acetate membranes. A wide range of membrane filter media are now commercially available to suit various applications cellulose esters, polyvinylidinefluoride, polytetrafluoroethylene (PTFE), and polyhexam-ethyleneadipamide (nylon 66), separately or as laminates with polyethylene, polypropylene, and polyester for more robust phy.sicai characteristics. 

Since fully cured thermoset sheets cannot be resoftened, forming is not appKcable to them. Common materials subjected to thermoforming are thermoplastics such as polystyrene, cellulose acetate, cellulose acetate butyrate, PVC, ABS, poly(methyl methacrylate), low- and high-density polyethylene, and polypropylene. The bulk of the forming is done with extruded sheets, although cast, calendered, or laminated sheets can also be formed. 

However, plasticizers can make brittle films less strong and, as a result, blending [101] or laminating [102] with other materials has been used to overcome this disadvantage. Aqueous blends of soluble starch and cellulose acetate have been studied intensively [103-107] as they have properties that make them suitable... 

Chem. Descrip. Triphenyl phosphate CAS 115-86-6 EINECS/ELINCS 204-112-2 Uses Rame retardant platinizing agent, plastidzer tor collodion cotton plastidzer w/o gelatinizing properties for acetyl cellulose reduces tiamm. ot NC and acetyl cellulose-based plastic compds. and lacquer films flame retardant plasticizer tor photographic film materials, surf, coatings, phenolic laminates, cellulose acetate film/compds., rubber articles made from acrylonitrile-butadiene, polychloroprene rubber Features Not compat. with PVC... 

Chem. Deserp. Tricresyl phosphate CAS 1330-78-5 EINECS/ELINCS 215-548-8 Uses Flame retardant plasticizer for PVC, syn. rubbers, cellulosic resin (except cellulose acetate), nitrocellulose lacquers and coatings, phenolic laminating resins... 

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