Rosin and derivatives

A plot of logio effective carbon chain length v. distribution coefficient gave a smooth curve for typical known ingredients. This curve was improved by correction for the effect of hydrogen bonding between tetrahydrofuran and the acidic components. 

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Rosin, modified rosins, and derivatives are used in hot-melt adhesives. They are based primarily on ethylene—vinyl acetate copolymers. The rosin derivative is used in approximately a 1 1 1 concentration with the polymer and a wax. The resin provides specific adhesion to the substrates and reduces the viscosity at elevated temperatures, allowing the adhesive to be appHed as a molten material. 

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. 

Rosin has a low order of toxicity foUowing ingestion or skin contact. Rosin and its numerous derivatives have a number of permitted food packaging and other direct and indirect food contact uses throughout the world. Sanctioned uses appHcable in the United States are outlined in U.S. Food and Dmg Administration (U.S. FDA) Regulations (2). Material Safety Data Sheets (MSDSs) for specific rosins and thein derivatives should be consulted before thein use. 

Rosin and Rosin Derivatives," Code of Federal Regulations Tide 21, Part 178.3870, U.S. Pood and Dmg Administration, Washington, D.C., Apr. 1995. 

Wood is the raw material of the naval stores iadustry (77). Naval stores, so named because of their importance to the wooden ships of past centuries, consist of rosin (diterpene resin acids), turpentine (monoterpene hydrocarbons), and associated chemicals derived from pine (see Terpenoids). These were obtained by wounding the tree to yield pine gum, but the high labor costs have substantially reduced this production in the United States. Another source of rosin and turpentine is through extraction of old pine stumps, but this is a nonrenewable resource and this iadustry is in decline. The most important source of naval stores is spent sulfate pulpiag Hquors from kraft pulpiag of pine. In 1995, U.S. production of rosin from all sources was estimated at under 300,000 metric tons and of turpentine at 70,000 metric tons. Distillation of tall oil provides, in addition to rosin, nearly 128,000 metric tons of tall oil fatty acids annually (78). 

Rosin and tall oil-based tackifiers are derived from feedstock, which is typically obtained by extraction and distillation of the materials from shredded tree stumps or wood chips. A typical structure of one of the different products obtained through this process is this abietic acid structure shown in Fig. 14 as a representative of the rosin acid family. 

Rosin and its derivates have shown wide compatibility with a broad range of acrylics and other PSA polymer precursors. This property has made them one of the most common tackifiers in the industry. 

In this section the rosins and rosin derivative resins, coumarone-indene and hydrocarbon resins, polyterpene resins and phenolic resins will be considered. The manufacture and structural characteristics of natural and synthetic resins will be first considered. In a second part of this section, the characterization and main properties of the resins will be described. Finally, the tackifier function of resins in rubbers will be considered. 

Rosins and rosin derivatives. The resins more commonly used in rubber base adhesives are rosin esters, particularly glycerol and pentaerythritol esters, as well as rosins modified by disproportionation and hydrogenation. The glycerol ester of hydrogenated rosin has been reported to be an excellent tackifier for polychloroprene adhesives (see pp. 344-357 in [17]). 

The acid number is mainly defined for rosins and rosin-derived resins and for phenol-modified resins. Standard hydrocarbon resins have zero acid number because the absence of functional groups. However, the acid number allows one to control deterioration by oxidation with formation of carbonyl and carboxyl groups in hydrocarbon resins. Typical acid number values of different resin types are ... 

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%. 

Naturally occurring rosins are derived from vegetable sources in the forms of exudates, i.e., gums. Rosin and rosin esters have found a number of applications within the rubber industry. Rosin acids are easily oxidised and thus it is more usual to find rosin presented to the rubber industry in a... 

There are several materials that make up this category, including wood-derived tall oil rosins and pine stump extracts sold under the well known VinsoH trade mark. They consist of complicated mixtures containing greater or lesser amounts of abietic acid (Fig 3.2) together with pimaric acid, and phenolic compounds such as phlobaphenes. 

Many terpenes are derived from renewable plant oil resources like essential oils. a-Pinene and -pinene from turpentine may be the best known examples, because they represent a very large volume. Turpentine was originally obtained from pine trees by tapping gum oleoresin from the stem of the living trees followed by steam distillation of the crude oleoresin and subsequently separation into rosin and turpentine by distillation. The ratio of a-pinene to -pinene in this turpentine varies considerably and depends a lot on the pine species from... 

The adhesives industry is the third most important market for rosin. Rosin, modified rosins, and rosin derivatives are used in several types of adhesives, including the pressure-sensitive, hot-melt, and elastomer-based latices, and solvent rubber cements. 

Derivation By boiling calcium hydroxide with rosin and filtering fusion of hydrated lime and melted rosin. 

Both the terms resin and plastic are in common use but there are no explicit definitions for them. The term resin originally referred to vegetable-derived organic products of relatively high molecular weight, the best known of which are rosin and balsam obtained from coniferous trees. But, the term is now used much more broadly, and rather loosely, to include the manmade polymeric substances used in a variety of applications, such as in plastics, textiles, and paints. It is often used interchangeably with the term plastic . 

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