Chemicals
One stop, integrated solution for all your paper finishing and optic chemicals requirements.
Pulping
Chemical pulping involves dissolving lignin in order to extract the cellulose from the wood fiber. The different processes of chemical pulping include the Kraft process, which uses caustic soda and sodium sulfide and is the most common; alternatively, the use of sulfurous acid is known as the sulfite process, the neutral sulfite semichemical is treated as a third process separate from sulfite, and soda pulping which is the least ecologically hazardous utilizing sodium hydroxide or anthraquinone.
Caustic soda is added to increase the pH in the pulping process of fibers. The higher pH of the paper-fiber solution causes the fibers to smoothen and swell, which is important for the grinding process of the fibers
Bleaching
In the production of white paper, the wood pulp is bleached to remove any color from the trace amounts of lignin that was not extracted in the chemical pulping process. There are three predominant methods of bleaching:
Elemental chlorine bleaching uses chlorine and hypochlorite.
Elemental chlorine-free bleaching is more environmentally friendly since it eliminates the use of hypochlorite and replaces chlorine with chlorine dioxide or sodium chlorate.
Totally chlorine-free bleaching utilizes oxygen and hydrogen peroxide. This is the most environmentally friendly process since it eliminates all chlorinated pollutants.
Sizing
Most paper types must have some water-resistance to maintain a specific writing quality and printability. Until 1980, the typical manner of adding this resistance was by using a rosin in combination with alum. When the paper industry started using chalk instead of china clay as filler, the paper chemistry had to switch to a neutral process. At several places AKD (alkyl ketene dimer) and ASA (alkenyl succinic anhydride) are used. Latest development is to use surface size,[5] which is applied using a size press. The advantage of surface sizing is that it does not interfere with the backend water chemistry.
Strengthening
Wet-strength
Wet-strength additives ensure that paper retains its strength when it gets wet. This is especially important in tissue paper. Chemicals typically used for this purpose include epichlorohydrin, melamine, urea formaldehyde and polyimines. These substances polymerize in the paper and result in the construction of a strengthening network.
To enhance the paper’s strength, cationic starch is added to wet pulp in the manufacturing process. Starch has a similar chemical structure as the cellulose fibre of the pulp, and the surface of both the starch and fibre are negatively charged. By adding cationic (positive charged) starch, the fibre can bind with the starch and thus also increase the interconnections between the fibres. The positively charged portion of the starch is usually formed by quaternary ammonium cations. Quaternary salts that are used include 2.3-epoxy propyl trimethyl ammoniumchloride (EPTAC, also known as or Glytac Quab, GMAC™) and (3-chloro-2-hydroxypropyl) trimethyl ammonium chloride (CHPTAC, also known as Quat 188, Quab 188, Reagens™).
Dry-strength
Dry-strength additives, or dry-strengthening agents, are chemicals that improve paper strength normal conditions. These improve the paper’s compression strength, bursting strength, tensile breaking strength, and delamination resistance. Typical chemicals used include cationic starch and polyacrylamide (PAM) derivatives. These substances work by binding fibers, often under the aid of aluminum ions in paper sheet.
Paper Cup Chemicals
Wood pulp refers to the pulp that is made from wood. Wood fiber is a treasure that has wide applications, such as paper pulp making, and wood-based activated carbon making. Wood is a common material for paper pulp production like straw, reed, jute and etc. As the most widely-used pulp, wood pulp takes 90% share of all paper pulp output. According to the pulp processing, the wood pulp can be classified into sulfate softwood pulp, mechanical wood pulp (also called groundwood pulp) and fined wood pulp. Softwood pulp and hardwood pulp are two different types of wood pulp, they have difference in fiber.