Terpenes polyterpenes

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). 

Terpenes are characterized as being made up of units of isoprene in a head-to-tail orientation. This isoprene concept, invented to aid in the stmcture deterrnination of terpenes found in natural products, was especially useful for elucidation of stmctures of more complex sesquiterpenes, diterpenes, and polyterpenes. The hydrocarbon, myrcene, and the terpene alcohol, a-terpineol, can be considered as being made up of two isoprene units in such a head-to-tail orientation (1). 

The other class of acrylic compatible tackifiers includes those based on ter-penes. Terpenes are monomers obtained by wood extraction or directly from pine tree sap. To make the polyterpene tackifiers, the monomers have to be polymerized under cationic conditions, typically with Lewis acid catalysis. To adjust properties such as solubility parameter and softening point, other materials such as styrene, phenol, limonene (derived from citrus peels), and others may be copolymerized with the terpenes. 

I.4. Polyterpene resins. Terpene resins are obtained from natural terpene monomers obtained from naval stores, paper pulp production, and citrus juice production. Terpenes are found in almost all living plants, and the turpentine oil from pine trees is the most important source. 

Tackifiers. Resins are generally added to adjust the desired tack. In general, resins must be used with plasticizers to obtain a good balance between tack and cohesive strength. Typical tackifiers are polyterpenes, although hydrocarbon resins and modified rosins and rosin esters can also be used. In some cases, terpene-phenolics or phenol-formaldehyde resins are added to increase adhesion. 

Polyterpenes. Polyterpenes is one of the first classes of non-polar tack-ifiers to be developed. Terpene monomers are a by-product in the extraction of rosin from wood stumps or tree sap, and from the extraction of oils from citrus fruits. The latter is the dominant source. As such, polyterpene prices generally mirror those of citrus fruits, which fluctuate substantially from one growing season to the next. Terpenes like rosin are cyclic, see Fig. 6, which is partly responsible for their excellent solvent properties. 

A class of hydrocarbons occurring in many essential oils of plants. They can be regarded as low-molecular weight polymers of isoprene (C5I I8)n. Dipentene is a terpene, while natural rubber, gutta percha and balata have been termed polyterpenes. 

Terpenes are built out of Cs-isoprene units. There is a variety of terpenes ranging from Cs-terpenes which are called hemiterpenes to tetraterpenes with C40 atoms. There are also terpenes with more Cs-units, such as natural rubber, which is a polyterpene. Terpenes are also classified by the number of carbon cycles in the molecule, e.g., monoterpenes can have up to two cyclic systems in one molecule. Examples of some monoterpenes are shown in Scheme 2 myrcene is acyclic,... 

The abovementioned materials can be mixed with one another. A series of other polymers and resins can also be added if the substances listed in 1 to 4 form the bulk of the material. Additional materials are PE, PP, low molecular weight polyolefins, polyterpenes (mixtures of aliphatic and cycloaliphatic hydrocarbons produced by polymerisation of terpene hydrocarbons), polyisobutylene, butyl rubber, dammar gum, glycerine and pentaerythritol esters of rosin acid and their hydration products, polyolefin resins, hydrated polycyclopentadiene resin (substance mixtures manufactured by thermal polymerization of a mixture mainly composed of di-cyclopentadiene with methylcyclopentadiene, isoprene and piperylene which is then hydrogenated). 

In addition to terpene s)mthases, the construction of terpenoid carbon skeletons in plants also involves a number of prenyltransferases distinct from those that make the Cio, C15 and C20 diphosphates. One class of prenyltransferases catalyses l -4 condensations of IFF with an FFF or GGFF starter unit to make long-chain polyterpenes, such as rubber, a linear hydrocarbon with cis (Z) double bonds and as many as 30000 isoprene units. The... 

Isoprene has the chemical formula of C5H8, therefore, each isoprene unit correlates to five carbons present in the skeleton. Terpene classification includes hemiter-penes, monoterpenes, sesquiterpenes, diterpenes, sesterterpenes, and triterpenes, each consisting of one through six isoprene units, respectively [16]. Additional terpene classifications include tetraterpenes, containing eight isoprene units, and polyterpenes, which include isoprene chains. The classification system is further divided into subclasses [15]. 

The aniline-formaldehyde class excludes aniline-formaldehyde modified with phenol-formaldehyde. The polyacrylonitrile class excludes styrene-acrylonitrile copolymers the polyterpene class excludes maleic anhydride terpene resins. 

Polyterpenes (polyterpenoids). Natural products made up of n C lo units (= 2 n isoprene building blocks) with n>4, the biogenesis of which generally obeys the isoprene rule. The most important P. are the tetra-terpenes (n=4) including carotinoids, ficaprenols, natural rubber, balata, and gutta-percha. The name is also used for hydrocarbon resins (terpene resins) prepared synthetically by polymerization of monoter-penes. 

Terpenes, terpenoMs. T. can formally be considered as polymerization products of the hydrocarbon iso-prene (see isoprenoids). Depending on the number of isoprene units the compounds are classified as mono-terpenes (C,o), sesquiterpenes (C,j), diteipenes(C2o), sesterterpene (C25), triterpenes (C30), tetraterpenes (C40), and polyterpenes. The steroids are derived from a group of triterpenes, the methylsterols. 

Definition Mixt. of hydrocarbons distilled from certain plants and trees such as pine and citrus consists of terpenes, sesquiterpenes, diterpenes, polyterpenes... 

Polysulfide elastomer. See Polysulfide Polytef. See Polytetrafluoroethylene Polyterpene resin. See Terpene resin... 

Synonyms Polyterpene resin Terpene polymer resin Classification Unsat. hydrocarbon thermoplastic resin Definition Thermoplastic resin obtained by polymerization of turpentine in presence of cataysts Properties Sol. in mostorg. soivs. 

Synonyms Polyterpene resin Terpene polymer resin... 

The occurrence of terpenes is ubiquitous. Natural terpenes are found in plants and animals in minute amounts. Especially in higher plants, terpenes characterize the type of plant (chemotaxonomy) mono- and sesquiterpenes in essential oils, sesqui-, di-, triterpenes in balsams and resins, tetraterpenes in pigments and polyterpenes in latexes.Therefore, terpenes are often emitted from natural products such as citrus fruits or trees, e.g. conifers. 

As the PSA industry evolved, natural rubber (NR) and styrene-butadiene rubber (SBR) were the primary elastomers used. Other backbone polymers were available but were used to a lesser degree. These other elastomers include polychloroprene, butyl rubber and nitrile rubber. Traditionally, formulations containing natural rubber have made use of polyterpene resins as tackifiers, particularly beta-pinene resins. The probable structure of a beta-pinene resin is given as follows and represents the terpene class of resins. 

Isoprene does not exist as such in nature, but it is found in the biosphere in the form of numerous polyisoprenes. These substances may be divided into three groups the lower terpenes, the carotenoids and the polyterpenes. 

Prenol lipids (PRs) are synthesized from the 5-carbon precursors iso-pentenyl diphosphate and dimethylallyl diphosphate. The simple iso-prenoids (linear alcohols, diphosphates, etc.) are formed by the successive addition of C5 imits and are classified according to the number of these terpene imits. This class includes the carotenoids, which are precursors of vitamin A and also possess antioxidant effects. Prenol lipids containing more than 40 carbon atoms are termed polyterpenes. 

Terpene resins will be effective as solid solvents for an elastomer when their Hildebrand solubility parameters are close to the Hildebrand solubility parameters of the respective polymer. For example, from Table 22.4 it can be seen that pure polyterpene resins are suitable tackifiers for poly(ethylene) (PE), natural rubber, and polybutadiene polymers. Further, terpene phenol resins are suitable tackifiers for poly(vinyl acetate), poly(methyl methacrylate), and poly(ethylene terephthalate). 

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