Relative tack

Trapping n. Printing of one ink film on another, in multicolor wet printing. Successful trapping depends upon the relative tack and thickness of the ink film applied. 

Fig. 13. Mastercurves of relative tack of an SBR versus reduced test rate at 23 C for various contact times, given in minutes for each curve. Ends of vertical lines are extreme values when failure was stick-slip (104).

Nolan JM, 5tack J, O Donovan O, Loane E, Beatty S (2007) Risk factors for age-related maculopathy are associated with a relative tack of macular pigment. Exp Eye Res 84 61-74. doi 10.1016/j.exer.2006.08.016... 

The green strength (strength of an unvulcanised rubber compound) of an rubber is the upper limit of the tack [2]. The ratio of the absolute tack divided by the green strength is sometimes referred to as relative tack. When the relative tack is close to one it may be... 

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). 

Calendering and Extrusion. Priction compounds are used to build up composite stmctures of fabric and mbber. The surface of the calendered fabric must have good green tack, and for that reason compounds to be calendered are best made from a slow crysta11i2ing pepti2able polymer such as Du Pont GRT or Baypren 610. The relative temperatures of the fabric and various roUs must be carefully controUed so that the polymer does not stick to the roUs yet penetrates the fabric (137). 

Adhesives, Coatings, and Sealants. Eor these appHcations, styrenic block copolymers must be compounded with resins and oils (Table 10) to obtain the desired properties (56—58). Materials compatible with the elastomer segments soften the final product and give tack, whereas materials compatible with the polystyrene segments impart hardness. The latter are usually styrenic resins with relatively high softening points. Materials with low softening points are to be avoided, as are aromatic oils, since they plasticize the polystyrene domains and reduce the upper service temperature of the final products. 

In another tack test, a steel ball of specified diameter is rolled down a grooved incline onto a conditioned surface area of pressure sensitive adhesive (ASTM D 3121, PSTC-6). The length of travel before it stops is the rolling ball tack (Fig. 2d) reported in millimeters. It is relatively inexpensive and simple to set up. Similar test variables to the probe tack test apply. 

The BR and PIB adhesives have permanent tack but relatively low cohesive strength. Cohesive strength is provided by adding natural rubber, fillers or tacki-fiers. Furthermore, these adhesives have excellent resistance to chemicals, oils and ageing. 

Terpene phenolic resins can also be added to polychloroprene latex without great reduction in hot strength as the resin content is increased, but contactability is reduced. However, an adhesion failure is obtained, even at the 50 phr level. Furthermore, terpene phenolic resins have relatively poor tack and impart the best... 

Imides - Polyimides (PI) have been conventionally prepared by the chemical or thermal cyclodehydration of polyamic acids formed from the solution reaction of aromatic tetracarboxylic dianhydrides and aromatic diamines. The early PI were insoluble and relatively intractable. The polyamic acid was the processable intermediate. However, the polyamic acid precursor has two major shortcomings, hydrolytic instability and the evolution of volatiles during the thermal conversion to PI. In addition, residual solvent was left in adhesive tapes and prepregs to obtain tack, drape and flow. During the fabrication of components, the evolution of volatiles caused processing problems and led to porosity in the part. As work progressed on PI, other synthetic routes were investigated (e.g. reaction of esters of aromatic tetracarboxylic acids with diamines... 

Similarly, crime networks can be disrupted by identifying the weak links in a criminal commodity chain, or by targeting those actors whose skills are in relatively short supply. For example, in 2000/2001, Australian law enforcement was able to significantly disrupt local heroin trafficking networks by focusing on the relatively small number of brokers who brought together suppliers, financiers, skilled traffickers, and street distributors. This tack would be less successful where the skills needed to conduct the criminal activity, as well as the incentives to do so, are widespread. 

In the literature, there are several reports that examine the role of conventional fillers like carbon black on the autohesive tack (uncured adhesion between a similar pair of elastomers) [225]. It has been shown that the incorporation of carbon black at very high concentration (>30 phr) can increase the autohesive tack of natural and butyl rubber [225]. Very recently, for the first time, Kumar et al. [164] reported the effect of NA nanoclay (at relatively very low concentration) on the autohesive tack of BIMS rubber by a 180° peel test. XRD and AFM show intercalated morphology of nanoclay in the BIMS rubber matrix. However, the autohesive tack strength dramatically increases with nanoclay concentration up to 8 phr, beyond which it apparently reaches a plateau at 16 phr of nanoclay concentration (see Fig. 36). For example, the tack strength of 16 phr of nanoclay-loaded sample is nearly 158% higher than the tack strength of neat BIMS rubber. The force versus, distance curves from the peel tests for selected samples are shown in Fig. 37. 

In both cases, rolling ball tack remains relatively constant unless the 0H/NC0 ratio becomes too low. In addition, no creep in static shear is observed at room temperature or 70°C at the ratio shown. 

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