Rosin adhesive tack

Compounding is quite different for the two systems. The solvent base system is dependent on magnesium oxide and a /-butylphenoHc resin in the formulation to provide specific adhesion, tack, and added strength. Neither of these materials have proven useful in latex adhesive formulations due to colloidal incompatibihty. In addition, 2inc oxide slowly reacts with carboxylated latexes and reduces their tack. Zinc oxide is an acceptable additive to anionic latex, however. Other tackifying resins, such as rosin acids and esters, must be used with anionic latexes to provide sufficient tack and open time. 

Rosin exploitation, a part of the so-called Naval Stores Industry, is at least as old as the construction of wooden naval vessels. In recent years, rosin components have attracted a renewed attention, notably as sources of monomers for polymers synthesis. The purpose of the present chapter is to provide a general overview of the major sources and composition of rosin. It deals therefore with essential features such as the structure and chemical reactivity of its most important components, viz. the resin acids, and the synthesis of a variety of their derivatives. This chemical approach is then followed hy a detailed discussion of the relevant applications, the resin acids and their derivatives, namely in polymer synthesis and processing, paper sizing, emulsion polymerization, adhesive tack and printing inks, among others. 

Rosin, Resin acids. Chemical modification. Paper sizing. Emulsion polymerization. Adhesive tack. Polymer chemistry and processing. Printing inks... 

In the earlier art, there was some consideration that partial incompatibility of the tackifier resin with the rubber was responsible for the appearance of tack, but this no longer is seriously held in light of continuing studies by many investigators. Aubrey [38] has addressed this in his review of the mechanism of tackification and the viscoelastic nature of pressure sensitive adhesives. Chu [39] uses the extent of modulus depression with added tackifier as a measure of compatibility. Thus in a plot of modulus vs. tackifier concentration, the resin that produces the deepest minimum is the most compatible. On this basis, Chu rates the following resins in order of compatibility for natural rubber rosin ester > C-5 resin > a-pinene resin > p-pinene resin > aromatic resin. 

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. 

Tackifiers. SBRs have poor tack, so addition of tackifiers is necessary. The tackifier increases the wetting of the adhesive and also increases the glass transition temperature of the adhesive. Typical tackifiers for SBR adhesives are rosins, aromatic hydrocarbon resins, alpha-pinene, coumarone-indene and phenolic resins. 

Tackifiers. Phenolic resins are added to increase strength, oils resistance and resiliency of NBR adhesives. On the other hand, tack and adhesive properties can be improved by adding chlorinated alkyl carbonates. To impart tack, hydrogenated rosin resins and coumarone-indene resins can be added. 

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%. 

A tackifier is hard low-molecular weight resin with a Tg higher than room temperature. It can give the highest tack to the adhesive when added at the proper amount. Petroleum resin, polyterpene, and rosin esters are typical tackifiers, which are all commercially available. 

The aspects relevant to the use of rosin as such, or one of the derivatives arising from its appropriate chemical modification as monomer or comonomer [12-14], have to do with the synthesis of a variety of materials based on polycondensations and polyaddition reactions of structures bearing such moieties as primary amines, maleimides, epoxies, alkenyls and, of course, carboxylic acids. These polymers find applications in paper sizing, adhesion and tack, emulsification, coatings, drug delivery and printing inks. 

Abalyn . [Hercules] Methyl rosinate resin with cortq>atibility, surf.-wetdng pnqrerties, vise., and tack used in rubber lacquers, inks, paper coatings, varnishes, adhesives, sealing oonq>ds., plastics, wood presovatives, and perfumes plasticizer, softener, tackifter. 

A certain percentage of resin is almost always incorporated into formulations, with resin content varying from 8 to 25%. Hydrocarbon resins are used most often, but rosin esters, terpenes, and indene resins, which are more heat stable, are also common. Resins provide better flow, hot-tack, adhesion, and wetting characteristics. 

Chem. Descrip. Highly hydrogenated wood rosin CAS 659974)6-0 EINECS/ELINCS 266041-3 Uses Tackifier, modifying resin in adhesives and hot-melt-applied decorative, pressure-sensitive, and heat-sealable coalings softener, tackifier for NR, SBR, NBR, HR, CR, chlorinated rubbers, PS, block copolymers, polyisobutylene, EVA improves tack, processing a pigment disp. in rubber... 

Hydrogenated rosin Hydroxypropyl methacrylate Jsobomyl acrylate Pentaeni hrityl tetrabenzoate Poly-o-methylstyrene Triethy lenemelam i ne adhesive modifier, delayed tack Pentaerythrityl tetrabenzoate adhesive modifier, hot-melt Glyceryl tribenzoate Neopentyl glycol dibenzoate Pentaerythrityl tetrabenzoate adhesive modifier, hot-melt block copolymer... 

Polychloroprene latex. Anionic or non-ionic latices can be used. The polymer determines the initial tack and open time, the bond-strength development and hot bond strength, the application properties and the adhesive viscosity. Anionic latices are stabilized with rosin soaps. Carboxylated polychloroprene latex is stabilized with polyvinyl alcohol and provides better freeze-thaw stability than the anionic types [78]. 

Polyken Tack and Shear Adhesion of a Carboxylated SBR Latex Tackified with an Emulsion of the Glycerol Ester of Hydrogenated Rosin or a Modified Cg Aromatic Resin Emulsion... 

As with most of the other sections of this chapter, the basic reference to the applications of rosin and its derivatives as components of adhesive formulations up to the mid-1980s, is the corresponding chapter by Kennedy et al. [73] of the classical Naval Store book. The major emphasis in that chapter was placed on the tackifying properties of rosin-based resins in pressure-sensitive, hot melt and sealant adhesives. Therefore, before proceeding to a critical bibliographic survey, it seems appropriate to define the concept of tack and its repercussion in the broad area of adhesion, as opposed to other contexts, like printing inks, paints and coatings. 

In solvent-borne rubber adhesives, a variety of solvents can be chosen to control drying rate, adjust viscosity and dissolve important ingredients. Resins can be added to improve tack, wetting properties, heat resistance, bond strength and oxidation resistance. The most common resins nsed in rubber-based adhesives are rosins, rosin esters, and terpene, coumarone-indene, hydrocarbon and phenobc resins. Plasticizers and softeners reduce hardness, enhance tack and decrease cost of rubber adhesive formulations. Paraffinic oils, phthalate esters and polybutenes are typical plasticizers. Fillers are not often added to rubber adhesive formulations because they reduce adhesion. However they are sometimes used because they decrease cost and increase solution viscosity. Carbon black and titanium dioxide are also used to provide colour to the adhesives. Clays, calcium carbonate and silicates are also common fillers in rubber adhesive formulations. For water-borne adhesives, typically protective colloid, preservative, defoamers, wetting agents and emulsifiers are included in the formulations. 

Tackifying resins generally constitute between 8 and 25% of the total adhesive system. The type of resin used influences flow, hot tack, adhesion and substrate ease of wetting. The most commonly used are hydrocarbon resins, such as different petroleum waxes, but many other types (rosin esters, coumarone-indene resins, terpene resins) imparting often some better characteristics, such as a better heat stability, are often used. 

Tackifier n. A substance (e.g., rosin ester) that is added to synthetic resins or elastomeric adhesives to improve the initial tack and extend the tack range of the deposited adhesive film. 

Pressure-sensitive adhesives must be very sticky, that is, exhibit high tack. The tack of an adhesive usually reaches a maximum in the range of 40 to 70°C above Tg. Frequently the polymer by itself is not sufficiently tacky for commercial purposes. To solve the problem, people dissolve tackifiers in the adhesive. A tackifier is a compound that increases the Tg of the material while lowering the modulus. By contrast, plasticizers decrease Tg, as well as lower the modulus. Tackifiers are often based on natural product derived rosins, obtained from ground-up pine tree stumps and related materials (95). These rosins are multicycUc steroid-like ring structures. 

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