Control pulp cooking for paper production
Chemical pulping is best defined as a typical process for paper pulp production, which includes pulp cooking, screening, washing, and bleaching. Kraft cooking or chemical pulp cooking, a traditional method in the paper-making industry, is a method for converting any fibrous source or wood chips into paper pulp. High quality papers can be produced with the chemical pulping method, as most of the lignin and hemicelluloses remaining in the wood are dissolved in the kraft cooking. The result is a better separation of the cellulose fibers. In simple terms, kraft cooking is the main step of paper pulping process. Paper and cardboard production are the largest non-food applications for starches. Starch adhesives are used in numerous process stages in paper and cardboard production:
- Wet end: Cationic starches are used as binder for paper fibers, providing strength to the resulting paper sheet.
- Surface sizing: The paper sheets are rewetted with starch solutions to reduce the paper’s tendency to absorb liquid, allowing inks to dry on the surface of the paper instead of being absorbed.
- Paper coating: Starch is used as binder in paper coatings, which improve the surface characteristics like hardness, whiteness, and gloss.
- Corrugated cardboard: Starch adhesives are applied to the tips of the corrugated sheet to glue it to the flat liner papers.
- Gypsum board: Starches are added to the gypsum plaster, providing strength to the board and acting as glue for the cured gypsum rock with the paper covering.
- Starch glues: Starch-based glues are used for book-binding, paper sack production, tube winding, gummed paper, envelop adhesives, wallpaper adhesives, school glues and bottle labeling.
Whether a batch cooking process or a continuous cooking process – controlling it with a SCHMIDT + HAENSCH process refractometer makes it more efficient.