Petroleum-based adhesives

Chromic acid concentrations m air (superseded by MDHS 52/3 (1998JJ Petroleum based adhesives m building operations Arsenic toxic hazards and precautions Spraying of highly flammable liquids... 

The date of the symposium on which this book is based marked the 15th anniversary of the severe petroleum shortage of 1973—1974. Much of the research presented in this volume was begun in the early 1970s in response to shortages of petroleum-based adhesives for the forest products industry when the nation was in the midst of a record-setting demand for housing materials. Left with this indelible memory, the forest products industry has supported the development of adhesives from renewable resources. 

Adhesives made from blood and casein were some of the first used in the wood products industry. They have been replaced in many applications by petroleum-based adhesives, which show improved performance or better economics. Despite this competition, they remain important in certain specialty areas due to their unique curing and bonding characteristics. 

Other Wood Adhesives. There is considerable interest in developing adhesives from renewable resources that can be used as a primary adhesive or as an adhesive component (an extender ) to replace a portion of petroleum-based adhesives. These natural and renewable resources include lignin, tannins, and natural oils such as soy bean and proteins. 

Prior to the 1930s all adhesives were based on natural products (eg, proteins such as animal blood, casein, soy protein). Use of adhesives from natural products steadily decreased thereafter with the development of synthetic polymers that had superior properties. Recently, renewed interest has been shown in using natural products to replace, entirely or in part, petroleum-based adhesive components with natural products, without sacrificing the performance levels achieved with modem petroleum-based adhesives. The purposes are often to reduce cost and dependence on petrochemicals, to reduce formaldehyde emissions, and improve selected properties (eg, biodegradability). 

Most of the recent efforts to develop uses for the condensed tannins have centered on their application in wood adhesives. Reviews by Pizzi (182, 186) and others (15, 78, 87, 93, 208) provide references to several hundred papers and patents on this subject. Despite world-wide research efforts on other sources of tannins, particularly since the 1972-1973 petroleum shortage, the mimosa or wattle tannins extracted from the bark of black wattle Acacia mearnsii) remain the major source of condensed tannins exploited commercially for adhesive manufacture. Of the approximately 100000 tons of wattle tannin produced annually, only about 10000 tons are used in wood adhesives, predominantly in South Africa but also in Australia and New Zealand (186). The extensive use of wattle tannins by the wood products industry of South Africa is impressive indeed, as these tannins have partly replaced phenol and resorcinol usage in adhesives for bonding of particleboard, plywood, and laminated timbers (182, 186, 213). Three factors have contributed to the success in use of wattle tannin-based adhesives, namely the comparatively high costs of phenol and resorcinol in the Southern Hemisphere, their resorcinolic functionality and low molecular weight and, perhaps most importantly, the commitment by the research and industrial communities of these countries to reduce the reliance of the forest products industry on petroleum-based adhesives. 

Synthetic, petroleum-based adhesive products that are supposed to be green are based on either solventless liquid, waterborne, or 100% solid adhesive systems. The study adds that over the last few years, green adhesives have experienced a positive growth rate at the expense of solvent-based adhesive systems. 

Plasticizers and Processing Aids. Petroleum-based oils are commonly used as plasticizers. Compound viscosity is reduced, and mixing, processing, and low temperature properties are improved. Air permeabihty is increased by adding extender oils. Plasticizers are selected for their compatibihty and low temperature properties. Butyl mbber has a solubihty parameter of ca 15.3 (f /cm ) [7.5 (cal/cm ) ], similar to paraffinic and naphthenic oils. Polybutenes, paraffin waxes, and low mol wt polyethylene can also be used as plasticizers (qv). Alkyl adipates and sebacates reduce the glass-transition temperature and improve low temperature properties. Process aids, eg, mineral mbber and Stmktol 40 ms, improve filler dispersion and cured adhesion to high unsaturated mbber substrates. 

Regulates the use, transport or storage of petroleum spirit and - as extended by other legislation - mixtures, e.g. adhesives, thmners or lacquers containing petroleum, and non-petroleum based solvents with a flash point <73°F. 

Hot melt adhesives based on poly(3HB-co-3HV) have also been described [119]. Hot melts are commonly used in bookbinding, bag ending and case and carton sealing and are mostly based on synthetic materials such as polyethylene, polypropylene ethylene-vinyl acetate and styrene block copolymers [119]. Hot melts based on PHAs alleviate the dependence on petroleum based materials and allow the development of biodegradable alternatives based on natural raw materials. 

Water is sometimes used as a solvent for water-soluble resins. Certain epoxy adhesives are available as water-based emulsion or latex formulations. In the early 1970s, during the time of the petroleum crisis, water-based adhesives were thought of as a possible replacement for solvent-based adhesives systems. However, water-based adhesives never met the lofty expectations primarily because of the time and energy required to remove water from the bond line, the corrosion that the water causes in drying ovens, and the poor moisture resistance of cured water-based adhesives. 

The replacement of petroleum-derived (nonrenewable) sources of adhesive raw materials with renewable sources will follow three basic strategies 1) renewable materials will be used to replace part of the required petroleum-derived adhesive systems, 2) new polymeric adhesives will be synthesized from renewable materials and totally replace petroleum-derived adhesive systems, or 3) the adhesives systems now based on petroleum-derived materials will continue to be used, but the adhesive raw materials will be derived from renewable sources instead of from nonrenewable ones. Carbohydrates are very versatile chemicals that can be utilized in all three strategies as demonstrated by the preceding discussion. 

Since the oil shortages of the 1970s, there has been a sustained search for materials to replace the petroleum-based resins used as durable adhesives for exterior wood products. Such alternatives are considered important, because supplies of petrochemicals for use in the wood industry could again become undependable. Ideally, the source of material for an adhesive would be readily available, possibly from materials already found near or used by wood processing plants, for example, agricultural or wood-based renewable resources. The purpose of this investigation was to explore the use of carbohydrates as constituents in water-resistant adhesives. 

A cooperation agreement was made in 1973 between DDS-RO and the Finnish Pulp and Paper Research Institute with the aim to develop products and processes on the basis of membrane filtration of effluents from the pulp and paper Industry. The cooperation with Dr. Kaj Forss section at FPPRI has been very successful. For instance, through an extensive development program UF has been found to be a feasible tool for the preparation of lignin for the Karatex ( ) plywood binder. This adhesive, which is made from ultrafiltered spent sulfite liquor (SSL) or kraft black liquor (KBL), can be used for partial replacement of the much more expensive petroleum based phenol-formaldehyde resin in plywood and other wooden boards. 

Surfactants are very important in the chemical industry, appearing in such diverse products as detergents, emulsion polymer-based adhesives, surface coatings, pharmaceuticals, cosmetics, motor oils, drilling muds used in petroleum prospecting, ore flotation agents,... 

From the above survey, it appears that the industrial use of furanic monomers such as furfuryl alcohol and furfural, i.e., chemicals based on renewable resources, as binders in foundry molds is highly successful. Similar furan-based resins can also be used as efficient adhesives in wood particle composites and thus are interesting alternatives to petroleum-based counterparts. The fact that the substitution of formaldehyde by furfural has not yet met with a reasonable industrial success probably stems from the higher cost of the furan aldehyde. The increasing pressure on the reduetion of formaldehyde emission and the renewable character of furfural should play in its favor in the near future. 

EcoSynthetix markets EcoSphere biolatex binder dispersions as a replacement for petroleum-based styrene butadiene latex. EcoSphere biolatex binders are based on starch derived from crops such as com, potatoes, and tapioca. Although the product was originally developed for the paper coating industry, it can also be applied in the textile coating industry. EcoSynthetix also produces EcoMer , a biobased building block to synthesize waterborne sugar-acrylic adhesives and resins. 

This type of bio-based adhesive can be used as sustainable substitute for petroleum-based... 

Uses Antioxidant, antiozonant for petroleum-based and synthetic lubricants, rubbers, and plastics (PU) scorch retarder for CR in food-pkg. adhesives in closure-sealing gaskets for food containers antioxidant/stabilizer for food-grade polymers, pressure-sensitive adhesives antioxidant in food-contact rubber articles for... 

Phenol-formaldehyde (PF) resins are widely used as thermosetting adhesives for exterior-grade wood composites. Since phenol is traditionally derived from petroleum-based products, the production of PF resins from such phenol is relatively expensive and subject to changes in the price of petroleiun. One approach for reducing the cost of PF resins is to replace the petroleum-based phenol with phenols derived from renewable materials. Numerous studies... 

A wide variety of general purpose cleansers is available with abrasive materials to facilitate the cleansing process. Conventional cleansers are petroleum-based and use pumice, sand, metal meshes, foams, rigid and textured plastics, and various composites as abrasive materials. Although these materials are effective, they are often too harsh for use in sensitive or soft areas. Further, many of the abrasives and their associated adhesives are not biodegradable so they remain in the plumbing and in the water system long after their use (2). 

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