Surface tack

Speciali2ed copolymer latices, which are inherently and permanently tacky, are available as pressure-sensitive emulsions. They are mechanically stable and have excellent machinabiUty. They are compatible with many other PVAc latices and, therefore, can be easily blended with other resins for modification of surface tack, peel strength, and creep. 

EVA polymers have been important for film manufacture. They are not competitive with normal film because of the high surface tack and friction which make them difficult to handle on conventional processing machinery. However, because of their somewhat rubbery nature, gloss, permeability, and good impact... 

Fillers are often employed to reduce the surface tack of the final product. Examples are talc and china clay. If powdered materials are added directly to a latex they compete for the emulsion stabiliser present and tend to coagulate the latex. They are therefore added as an aqueous dispersion prepared by ball milling the filler with water and a dispersing agent, for example a naphthalene formaldehyde sulphonate at a concentration of about 1% of the water content. Heat and light stabilisers which are solids must be added in the same way. 

A compounding ingredient which enhances the surface tack of uncured rubber compounds. Tackifiers, exemplified by pine tar are classed under softeners and processing aids . 

An instrument for measuring the surface tack of sheet materials. 

Elastomer compounds can be plasticized by addition of organic compounds. Elastomer compounds are inherently flexible and selection of a base polymer on the basis of molecular weight characteristics, chemical composition, and degree of crystallinity serves as the basis for the properties of the compound from which an elastomer is made. Oils are the most common plasticizer for elastomers. Oils of paraffinic structure or aromatic structure can be used with elastomers in which they are compatible. Paraffin wax would also be included in this category. Other plasticizers include phthalic acid esters and adipic acid esters. Fatty acids can be used as plasticizers but these contribute to an increase in surface tack of elastomer compounds. Examples include stearic and palmitic acid. Plasticizer addition has the added benefit of aiding with incorporation of inorganic materials. 

However, three areas fire retardancy, dirt pick up, and surface tack do exist as outstanding issues in this field and solutions to them exist. Perhaps future work will address these problems. 

Reasons for use compatibility, low transfer to material in contact, low volatility, oxidation and thermal stability, reduced coefficient of friction, reduced surface tack, weather stability... 

Potential adverse effects affect color and/or gloss, decrease gelation, increase surface tack, lower impact resistance, overlubrication, plate-ont, problems with welding, reduce dimensional stability, reduce output... 

Surface Tack Stickiness of a surface of a material such as wet paint when touched. 

The resulting dehydrated castor oil (Z)CO), although it contains no fatty acids with three double bonds, has such a high proportion of acids with two double bonds, including some conjugated unsaturation, that it is a drying oil. It does, however, dry to a film with a noticeable surface tack. 

In pressure sensitive tapes plasticizer participates in the development of surface tack. Older versions of pressure sensitive tapes suffered from poor heat resistance, creep failure, reduced tack at lower temperatures, poor resistaiKe to UV and extensive bleeding. These drawbacks can be corrected by the proper selection of the plasticizer. 

Surface tack was optimized by the careful selection of matrix materials and tacldfiers as well as of plasticizers. The selections and concentrations of other components helps to determine the concentration of plasticizer which is variable as seen in Section 11.12.2. 

One property common to UV-cure.d acrylate formulations as was discussed earlier is relatively poor surface-cure due to oxygen inhibition (see Fig. 1). This effect is most predominant at low photoinitiator concentrations, in thin coatings. Adhesive formulations can benefit from this property by enhancing surface tack via the presence of residual uncured resin. Post-cure, from residual cross-linking, or other anaerobic chemistry, can later result in enhanced bond strength. 

Tackifiers. Pine tar, coumarone-indene resins, zylol-formaldehyde, and other resins are used to increase the tack of rubber compounds. Tack, here, means stickiness of the un-cmed rubber stock to itself, rather than to other things, such as metal surfaces. Tack has also been called autoadhesion. It is extremely important for building up structures such as tires. Natural rubber inherently has good natural tack, but most synthetic rubbers do not. 

Latex compounds have been typically used in paper, textile and construction. One of the most popular applications is their use in self-sealing envelopes. This application is based on the fact that when NR dries, some soluble non-rubber compounds migrate to the surface by water transport, leaving a thin film when drying is completed. This film reduces the surface tack on the rubber, and when pressed against a similar film, the non-rubber layer is displaced, allowing the two rubber surfaces to create a bond. 

The greater adhesion to painted surfaces (see Fig. IV. 11) is clearly explained as a manifestation of surface tack, which increases with increasing temperature. 

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