Terpene-based resins

Terpene-based resins Terpene hydrocarbons Terpeneless lime oil Terp ene-phenolics Terpenes... 

Terpene-based hydrocarbon resins are typically based on natural products such as a-pinene, P-pinene, and ti-limonene [5989-27-5] which are obtained from the wood and citms industries, respectively. These resins, which were originally the preferred tackifiers for natural mbber appHcations, possess similar properties to aHphatic petroleum resins, which were developed later. Terpene-based resins have been available since the mid-1930s and are primarily used in the adhesives industry. 

Hazardous Chemicals luvolved Kester tin/lead (63%/37%) solder, solder dross, and resin flux (mixture of alcohols and terpene based resins). 

Terpene-based resins are obtained from turpentine sulfate, a byproduct of the paper industry, and from limonene, a product of the citrus industry. Products obtained are alpha-pinene, beta-pinene, and dipentene. The alpha-pinenes are apparently the preferred product for hot melt adhesives as they are the most compatible with EVA copolymers. Adhesives compounded with dipentenes have excellent color and thermal stability, odor, oxidation resistance and hot tack properties. Typical of the products available in this class are the Piccolyte series of resins (Hercules). Limonene-based products are exemplified by Zonatac 105 (Arizona Chemicals). 

Other natural product-based resins also became widely used, such as the light colored Lewis acid oligomerized products of terpenes such as a-pinene, p-pinene, and limonene. These natural product resins are relatively expensive, however, and formulators now often use the newer, less expensive synthetic resins in present day natural rubber PSAs. These are termed the aliphatic or C-5 resins and are Lewis acid oligomerized streams of predominately C-5 unsaturated monomers like cis- and /rawi-piperylene and 2-methyl-2-butenc [37]. These resins are generally low color products with compatibility and softening points similar to the natural product resins. Representative products in the marketplace would be Escorez 1304 and Wingtack 95. In most natural rubber PSA formulations, rubber constitutes about 100 parts and the tackifier about 75-150 parts. 

Ethylene-vinyl acetate copolymer, terpene-phenol resins, polyethylene oxide, PMMA and some of their blends were solution cast on basic (aluminium oxide) and acidic (hydroxylated glass) substrates. Fourier transform infrared reflection absorption spectroscopy (IRRAS) was used to determine both the nature and the free energy of interfacial adduct formation in the polymer/metal systems. A correlation between IRRAS and adhesive strength may be used to predict both the acid-base work of adhesion and the density of interfacial interacting sites. 14 refs. 

A more scientific classification takes into account resin structure. One can thus distinguish between aliphatic, cycloaliphatic, aromatic, and mixed HRs. Cycloaliphatic HRs include terpenic resins and cyclopentadiene-based resins. A similarity can be noticed, likely to cause confusion, between aliphatic and cycloaliphatic resins. This is because aliphatic resins often contain cyclic structures, arising from the presence of cyclopentadiene and cycloolefins in monomer mixtures subjected to polymerization and from cyclization accompanying some of the polymerization processes. Aromatic HRs include the products produced by polymerization of Cs-Cio fractions and CIRs. Mixed resins are made up of complex structures. Their properties will be modulated in terms of component proportion. Thus, these resins can produce various materials that also prove valuable from the technical point of view [8]. 

Most PSAs are based on natural rubber. Rubber by itself has very low tack and adhesion to surfaces thus requires addition of tackifying resins based on rosins, petroleum, or terpenes. Hydrogenated resins are... 

Heteroatom functionalized terpene resins are also utilized in hot melt adhesive and ink appHcations. Diels-Alder reaction of terpenic dienes or trienes with acrylates, methacrylates, or other a, P-unsaturated esters of polyhydric alcohols has been shown to yield resins with superior pressure sensitive adhesive properties relative to petroleum and unmodified polyterpene resins (107). Limonene—phenol resins, produced by the BF etherate-catalyzed condensation of 1.4—2.0 moles of limonene with 1.0 mole of phenol have been shown to impart improved tack, elongation, and tensile strength to ethylene—vinyl acetate and ethylene—methyl acrylate-based hot melt adhesive systems (108). Terpene polyol ethers have been shown to be particularly effective tackifiers in pressure sensitive adhesive appHcations (109). 

Pressure sensitive adhesives typically employ a polymer, a tackifier, and an oil or solvent. Environmental concerns are moving the PSA industry toward aqueous systems. Polymers employed in PSA systems are butyl mbber, natural mbber (NR), random styrene—butadiene mbber (SBR), and block copolymers. Terpene and aUphatic resins are widely used in butyl mbber and NR-based systems, whereas PSAs based on SBR may require aromatic or aromatic modified aUphatic resins. 

Terpene resins, because of their low odor and acceptable FDA clearance, are used as tackifiers for the natural and synthetic gum bases used in chewing gum. Selected petroleum resins are also used as gum bases. 

Odour. This aspect is important in resins derived from natural sources. Rosins based on wood and gum rosin retain trace quantities of terpenes and have a piney odour. Tall oil rosins retain the typical sour odour of the rosin. Odour can be removed by steam sparging under vacuum before or during esterification of rosins. Addition of odour masks can also be done. 

Adhesion depends on a number of factors. Good adhesion is defined by most customers as substrate failure. The major adhesive manufacturers possess equipment that allows them to make bonds with customer substrates under conditions that closely simulate actual packaging lines. These bonds are peeled either automatically or by hand to gauge adhesion. The most important factors influencing adhesion are the wet-out of the substrate, partieularly by the polymer component of the adhesive system, and the specific adhesion with the substrate. Choice of resin is critical for both. Rosin, rosin esters and terpene phenolics are eommonly added for these purposes in EVA and EnBA-based systems. Adhesion at low temperatures is also influenced by the overall toughness of the system at the test temperature. 

Standard-grade PSAs are usually made from styrene-butadiene rubber (SBR), natural rubber, or blends thereof in solution. In addition to rubbers, polyacrylates, polymethylacrylates, polyfvinyl ethers), polychloroprene, and polyisobutenes are often components of the system ([198], pp. 25-39). These are often modified with phenolic resins, or resins based on rosin esters, coumarones, or hydrocarbons. Phenolic resins improve temperature resistance, solvent resistance, and cohesive strength of PSA ([196], pp. 276-278). Antioxidants and tackifiers are also essential components. Sometimes the tackifier will be a lower molecular weight component of the high polymer system. The phenolic resins may be standard resoles, alkyl phenolics, or terpene-phenolic systems ([198], pp. 25-39 and 80-81). Pressure-sensitive dispersions are normally comprised of special acrylic ester copolymers with resin modifiers. The high polymer base used determines adhesive and cohesive properties of the PSA. 

However, styrene and cyclohexene gave complex product mixtures, and 1-octene did not react under the same reaction conditions. Thus, the activity of this catalyst is intrinsically low. Jacobs and co-workers [159,160] applied Veturello s catalyst [PO WCKOj ]3- (tethered on a commercial nitrate-form resin with alkylammonium cations) to the epoxidation of allylic alcohols and terpenes. The regio- and diastereoselectivity of the parent homogeneous catalysts were preserved in the supported catalyst. For bulky alkenes, the reactivity of the POM catalyst was superior to that of Ti-based catalysts with large pore sizes such as Ti-p and Ti-MCM-48. The catalytic activity of the recycled catalyst was completely maintained after several cycles and the filtrate was catalytically inactive, indicating that the observed catalysis is truly heterogeneous in nature. 

The adhesive tie layer can be made up from 82% ethylene-based octene plastomer, 15% styrene modified terpene resin and 3% of a styrene/isoprene/styrene styrenic block copolymer. 

Turpentine oils extracted from pine resins are now marginal sources of terpenes pinenes, carene and some other monoterpenes are essentially obtained from the paper oils produced in the KRAFT process. Nevertheless this process is based on a treatment of wood chips in sodium sulfide, which leaves significant fractions of sulfur compounds in the paper oils. For the use of terpenes, these sulfur compounds must be eliminated. The process requires ... 

Organic components of polishes are widespread. Thus most products emit complex VOC mixtures that may consist of alkanes, various alcohols, acetates, C2-C4-benzenes, terpenes and derivatives of naphthalene. This is illustrated by the range of compounds emitted by a furniture polish (Figure 15.2b) and a shoe polish (Figure 15.2c). Many modern floor waxes are based on natural ingredients like alkyd resins. On oxidative degradation of unsaturated fatty acids, volatile aliphatic aldehydes (C5-C11) with unpleasant smell (Ruth, 1986) are formed and the emission rates may remain at high levels over months and even years (Salthammer, 1999). 

Terpenes are obtained either by processing wood in the kraft process in paper production or by collecting resins and turpentine from conifers. The scale of produced terpenoids in comparison with fats and oils is small. Applications for terpenes are in pure form as solvents, as odorous substances, or in dyes. Most terpenoids contain double bonds which are readily available to perform chemical reactions. A widespread component of turpentine is a-pinene, from which many fragrances are produced. A further often-used resource is myrcene, which is obtained by pyrolysis of (3-pinene. Myrcene is an important base chemical to produce, for example, the fragrances nerol and geraniol [7]. 

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