Specialty paper grades

Anionic starches are obtained by reaction with phosphoric acid and alkali metal phosphates or by derivatization with carboxymethyl groups.30,31 This modification is primarily used to introduce amphoteric properties into cationic com starch for application on the wet end of the paper machine. Anionic starches with carboxymethyl substitution are used as thickeners in coating colors or as binders in coatings for specialty paper grades. Oxidized starches are inherently anionic but without thickening action. Potato starch already carries sufficient natural anionic charge to provide amphoteric properties after cationization.32... 

In specialty paper and tissue production, online measuring technique has often not been used in closed-loop control in the past because of many grade changes and complex process chemistry. Small production volumes and slow running machines were not supporting acceptable payback calculations for investments in measuring technology. 

Table 2.4 Paper grades and range of fillers and/or specialty pigments applied.

This is a specialty and particularly effective filler. It is appHed in specialty papers, often at low basis weights, with particularly high demand in dry and wet opacity and sheet brightness. Ti02 can be found in thin print paper, i.e. bible paper, high opaque grades, label paper and decoration paper. 

The category of specialty papers defines a very wide range of different paper grades with a wide variety of specialized end uses and thus different and particular quality demands. These require special production technologies and specific know-how. Some of the required properties are very common and similar to commodity papers, but they are usually more distinct or with a closer tolerance. Such characteristics include profile quality, formation, smoothness, strength, thickness, porosity, and absorption. Some are very particular characteristics, such as wet strength, electrical conductivity, pore size distribution, resistance to certain chemicals, chemical reactivity, fight proofness, heat resistance, and cleanliness. 

The basic raw material for specialty papers is wood pulp. There are however grades like tea bag, plug wrap or filter paper where the required porosity, absorb-... 

The press sections in specialty paper machines need to be highly flexible. For paper grades where only one smooth side is required, multi-roll press concepts with two or three press nips and a closed sheet run can be used. For increased dryness and improved runnability these press concepts can be equipped with a... 

Specialty papers can be divided into uncoated and coated grades. The uncoated grades are either machine finished, like cigarette papers or base papers for sub-... 

Further important criteria for paper and board grades used for packaging include low odor, flexibility, fold crack stability, glue-ability, and grease resistance. Coated specialty papers require specific properties, such as alkali resistance (labels), washability (wallpaper), and solvent resistance (silicone release paper). 

Other sources of fibers include cotton rags and linters, flax, hemp, bagasse, tobacco, and synthetic fibers such as polypropylene. These substances are not used widely, however, as they are typically for low-volume, specialty grades of paper. 

Before discussing specialty starches for size press applications, it should be noted that the largest volume of starch applied at the size press is either enzyme converted or ammonium persulfate hydrolyzed native corn starch. These are economic considerations and the properties resulting from these treatments do not compare to the properties provided by specialty starches. It is also fair to state that all grades of paper do not require a specialty starch and it is only through the need for improved paper performance that specialty starches are required. 

Specialty Furnace Carbon Blacks - four Raven grades for news-ink, paper and UV protection... 

Carbon black finds its way into many products inks, paints, paper, fertilizer, plastics, and explosives to name a few. By far the major use, however, is in automotive tires which consume 65% of the total production. The present day tire contains roughly 1 pound of carbon black for each 2 pounds of rubber and provides both the bounce and wear characteristics desired by the user. The properties carbon black imparts to rubber compounds are so critical that there are currently more than 20 classified grades of oil blacks. Most distinctions between grades are mainly a function of particle size and structure, although surface chemistry is sometimes a factor for specialty uses. The more important grade designations are illustrated in Table I. Each of those listed are also subdivided according to their structure levels. 

This paper focuses on the development of specialty grades of acetal copolymer that yield excellent sharp, clear images when laser marked. Specifically grades have been developed for laser marking on general purpose parts. Additional grades have been developed for laser... 

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