Sack Kraft Paper or paperboard is a high-strength, high-stretch paper or paperboard material made from kraft Pulp. It is used for packaging products such as food, beverages, and industrial products. Sack kraft paper is also used in the manufacture of bags, sacks, and envelopes. There are two types of sack kraft paper: natural brown kraft paper and bleached kraft paper. Brown kraft paper is made from 100% virgin kraft pulp and has a natural brown color. Bleached kraft paper is made from a blend of virgin kraft pulp and recycled kraft pulp and has a bright white color. Sack kraft paper is available in a variety of basis weights, finishes, and grades. Basis weight is the weight of 1,000 square feet of paper in pounds. Common basis weights for sack kraft paper range from 35 to 150 pounds. Finish is the surface texture of the paper. Common finishes for sack kraft paper include vellum, smooth, and coated. Vellum finish is the roughest finish and is typically used for products that do not require a high-quality finish such as bags for animal feed or mulch. Smooth finish is a mid-range finish that is typically used for products such as cement bags. Coated finish is the smoothest finish and is typically used for products such as food bags. Grade is the strength and stiffness of the paper. Common grades for sack kraft paper include A, B, C, and D. Grade A is the weakest grade and is typically used for low-strength applications such as envelopes. Grade B is a mid-range grade and is typically used for applications such as cement bags. Grade C is a high-strength grade and is typically used for applications such as food bags. Grade D is the strongest grade and is typically used for applications such as shipping containers. Sack kraft paper is produced by a variety of manufacturers around the world. Some of the largest producers of sack kraft paper include International Paper, Smurfit-Stone Container, and Weyerhaeuser.