Resins natural

However, there has been some interesting work in the USA on soybean, as a potential source of TS binder resins. These resins are being developed by the United Soybean Board, St Louis, Missouri, USA, under the name Proteinol. They are made from various waste cellulosic fibers tightly bound with various soy protein/phenolic binder systems. Fillers can be agricultural crop wastes such as wheat straw, corn, bagasse, kenaf, or hemp, forest waste products such as wood fibers, shavings, sawdust or chips, and shredded newsprint, de-inked office paper, and other recycled products. Extruded and compression molded shapes are being produced, which can be nailed, drilled, sawn, routed, sanded, painted and stained. 

Practically all plastics are compounded with other products (additives, fillers, reinforcements, etc.) to provide many different properties and/ or processing capabilities. It includes mechanical mixing/blending. They do not normally depend on chemical bonds, but do often require special compatibilizers. Mechanical compounding is extensively used worldwide. 

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It was first described in 1608 when it was sublimed out of gum benzoin. It also occurs in many other natural resins. Benzoic acid is manufactured by the air oxidation of toluene in the liquid phase at 150°C and 4-6 atm. in the presence of a cobalt catalyst by the partial decarboxylation of phthalic anhydride in either the liquid or vapour phase in the presence of water by the hydrolysis of benzotrichloride (from the chlorination of toluene) in the presence of zinc chloride at 100°C. 

Resin and Polymer Solvent. Dimethylacetamide is an exceUent solvent for synthetic and natural resins. It readily dissolves vinyl polymers, acrylates, ceUulose derivatives, styrene polymers, and linear polyesters. Because of its high polarity, DMAC has been found particularly useful as a solvent for polyacrylonitrile, its copolymers, and interpolymers. Copolymers containing at least 85% acrylonitrile dissolve ia DMAC to form solutions suitable for the production of films and yams (9). DMAC is reportedly an exceUent solvent for the copolymers of acrylonitrile and vinyl formate (10), vinylpyridine (11), or aUyl glycidyl ether (12). 

A varnish is often appHed on top of the paint layers. A varnish serves two purposes as a protective coating and also for an optical effect that enriches the colors of the painting. A traditional varnish consists of a natural plant resin dissolved or fused in a Hquid for appHcation to the surface (see Resins, natural). There are two types of varnish resins hard ones, the most important of which is copal, and soft ones, notably dammar and mastic. The hard resins are fossil, and to convert these to a fluid state, they are fused in oil at high temperature. The soft resins dissolve in organic solvents, eg, turpentine. The natural resin varnishes discolor over time and also become less soluble, making removal in case of failure more difficult (see Paint and FINNISH removers). Thus the use of more stable synthetic resins, such as certain methacrylates and cycHc ketone resins, has become quite common, especially in conservation practice. 

Web Heat-Set Publication and Commercial Inks. Almost all heat-set inks are now printed on web offset presses, and are based on vehicles containing synthetic resins and/or some natural resins. These are dissolved in hydrocarbon solvent fractions which are specially fractionated for use in the ink industry. They vary in boiling range between 180 and 300 °C. Small percentages of alkyd resins (qv) may be contained in these inks. They dry in less than one second by means of solvent evaporation in a heatset oven. These ovens utilize high velocity hot air to raise the web temperature to 120-150 °C. 

Resin and Resinoid. Natural resins are plant exudates formed by the oxidation of terpenes. Many are acids or acid anhydrides. Prepared resins are made from oleoresins from which the essential oil has been removed. A resinoid is prepared by hydrocarbon extraction of a natural resin. 

Modem furniture pohshes are designed for a wide variety of surfaces, eg, plastics, metals, and synthetic and natural resin coatings. Furniture pohshes impart shine and provide protection from abrasion, marring, and spills. The formulations clean weU in many cases. In common with most other pohshes, furniture pohshes are characterized by ease and speed of apphcation and of buffing, and by either the absence of objectionable odors or the addition of pleasing ones. 

Natural resins are generally described as solid or semisolid amorphous, fusible, organic substances that are formed in plant secretions. They are usually transparent or translucent yeUow-to-brown colored, and are soluble in organic solvents but not in water. The principal uses for natural resins are in varnishes, printing inks, adhesives, paper size, and polymer compositions. The term natural resins includes tree and plant exudates, fossil resins, mined resins, and shellac. They often have been altered from their original state during isolation and processing. For some appHcations, the resins have been chemically modified to increase their industrial utiUty. 

Natural resins were probably known to early people, who recognized them as exudates from trees. Collection and use of these resins have been recorded by early Roman and Greek historians. Many products have been collected by the same methods throughout history to the present time. However, increased labor costs and competition from synthetic resins have reduced the demand for some natural resins, so they have become less available. In other cases, such as that of rosin, the traditional collection of gum from trees has been supplemented or replaced by isolation from other sources, such as paper pulping and tree stumps. 

Natural resins have been collected by hand throughout recorded history and used with minimal processing. They are reported to have been used in the arts, both in paints and for polishing sculptures, as early as 350 BC. Amber, the hardest of these resins, has been used as a gemstone from early Greek history to modem times. The electrical properties of amber were first recorded about 300 BC. Following is a description of commercial natural resins that are available in the United States. 

Gum Elemi. This resin, tapped from trees in the Philippines, contains a higher concentration of essential oils than other natural resins. It is a soft, sticky, plastic material that can be deformed manually. Gum elemi [9000-75-3] contains 20—25% essential oils, 13—19% acids, 30—35% resenes (condensed decarboxylated resin acids), and 20—25% terpenic resinols (condensed terpene alcohols). It has an acid number of 20—35 and a saponification number of 20—40. Gum elemi is a film-forming plasticizing resin used in lacquers. 

The natural resins described here are those that have been mentioned in technical Hterature they can be identified by CAS Registry Numbers and Merck Index numbers (1). 

Unlike other natural resins, shellac [9000-59-3] is derived from the hardened secretion of the lac insect (species l ccifer (Tachardia) lacca Kerr (family Coccidae), also known as Kerns lacca (Kerr)). Shellac is a refined grade of the cmde lac secretion and is the most widely known lac product. Therefore, shellac has been accepted as the common generic term. Over 50% of the world s supply is produced in the Indian provinces of Bihar and Orissa, with the remainder originating in adjacent areas of southeast Asia such as Sri Lanka, China, Thailand, and Myanmar. 

Rosin and its derivatives are economically the most important natural resins. Approximately 1150 x 10 metric tons of these materials are produced annually and sold throughout the world. The principal producers are the People s RepubHc of China (ca 40%) and the United States (ca 25%), followed by Russia. Most of the remainder is produced in Indonesia, Portugal, Finland, India, Bra2il, and Mexico. In 1996, the lowest grades of rosin were priced at 750/t. Most rosin is converted to its many derivatives to meet requirements for industrial appHcations. The principal producers of rosin derivatives are Ari2ona Chemical Company, Hercules Incorporated, Westvaco, Union Camp, and Georgia-Pacific. 

The traditional natural resins are collected or isolated from trees, primarily in the more moderate climates of the world. Before World War II, annual consumption of these resins in the United States was about 18,000—23,000 t. This dropped to about 9000 t/yr by the late 1940s. The total imported volume in 1995 is estimated at <500 t. These resins have been replaced by synthetic resins in most industrial appHcations. Traditional natural resins are sold in bulk quantities for about 1.32— 6.60/kg. Special grades of these resins are sold for as much as 132/kg. The largest importer of traditional natural resins is P. 

Natural resins such as dammar and Manila copal have been described in U.S. FDA Regulations (3). The Material Safety Data Sheets for these products issued by the importer describe them as nontoxic and nonaUergenic. 

N. Heaton, Outlines of Paint Technology Chades Griffin Co., London, 1947, pp. 280—305. Also contains information on classical natural resins and sheUac. Technical Hterature, Hercules Incorporated, Wilmington, Del. Information also avaUable on mined resins. 

Natural Resins Handbooks American Gum Importers Association, New York, 1939. 

Further east another natural resin, lac, had already been used for at least a thousand years before Pliny was bom. Lac is mentioned in early Vedic writings and also in the Kama Sutra of Vatsyayona. In 1596 John Huyglen von Linschoeten undertook a scientific mission to India at the instance of the King of Portugal. In his report he describes the process of covering objects with shellac, now known as Indian turnery and still practised ... 

In addition to shellac a number of other natural resins find use in modem industry. They include rosins, copals, kauri gum and pontianak. Such materials are either gums or very brittle solids and, although suitable as ingredients in surface coating formulations and a miscellany of other uses, are of no value in the massive form, i.e. as plastics in the most common sense of the word. 

X-ray evidence shows the material to be completely amorphous as might be expected from such a complex mixture. The specific gravity ranges from 1.05 to 1.10. It is slightly harder than gypsum and therefore just not possible to scratch with a fingernail. Yellow in colour, it is less brittle than other hard natural resins and may therefore be carved or machined with little difficulty. The refractive index is 1.54. 

GiDVANi, B. s. Shellac and Other Natural Resins, Plastics Institute Monograph No. SI, 2nd Edn. London (1954)... 

Resins can be divided into natural and synthetic types. Natural resins have a vegetable or animal origin. Typical examples are rosins. Synthetic resins result from controlled chemical reactions, and can be divided into two subgroups. 

Tackifiers. The tackifiers usually are hydrocarbon resins (aliphatic C5, aromatic C9) or natural resins (polyterpenes, rosin and rosin derivates, tall oil rosin ester). They improve hot tack, wetting characteristics and open time and enhance adhesion. The content on tackifiers in a hot melt can be in the region of 10-25%. 

Class of colloidal substances prepared from plants. Composed of complex carbohydrates and organic acids that swell in water. Also, a number of natural resins are gums. 

A surface coating protects the substrate against abrasion, moisture, light, and corrosion. The binder for the pigment and extenders is fluid before application and rigid soon after. Natural binders range from gum arable to fish oil. The first varnishes were solutions of natural resins, having transparency, hardness, amorphous structure, and little permanence. 

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