For those new to the paper industry, it can be challenging to differentiate between white kraft paper and woodfree paper. Many assume they are the same, but in reality, they have distinct characteristics. Below is a detailed comparison to help distinguish between these two types of paper.
1. Basis Weight (GSM)
- White Kraft Paper: Standard basis weight ranges from 60gsm to 250gsm. Additionally, low-weight white kraft paper includes 30gsm, 35gsm, 40gsm, 45gsm, 50gsm, while high-weight options include 250gsm, 300gsm, 350gsm, 400gsm.
- Woodfree Paper: Standard basis weight ranges from 70gsm to 250gsm. Other available weights include 55gsm, 58gsm, 65gsm, 68gsm for lower weights and 290gsm, 300gsm, 350gsm, 390gsm, 400gsm for higher weights.
2. Material Composition
- White Kraft Paper: Made from bleached softwood kraft pulp (needle-leaf sulfate bleached pulp), featuring long fibers, strong tensile strength, high tear resistance, and good stiffness. It is also environmentally friendly.
- Woodfree Paper: Generally made from bleached chemical needle-leaf wood pulp with an appropriate amount of bamboo pulp. The production process includes heavy filling and sizing treatments, and some high-grade woodfree papers undergo surface sizing and calendering.
3. Applications and Processing
- White Kraft Paper: Used for paper bags, tote bags, document bags, packaging bags, food packaging bags, envelopes, and product packaging. It can also be processed for lamination, mounting, embossing, and dyeing.
- Woodfree Paper: Extensively used for books, textbooks, color pages, magazines, product catalogs, maps, calendars, inserts, posters, corporate brochures, flyers, product manuals, office paper (such as copy paper), business cards, color labels, and various packaging materials.
4. Detailed Analysis of Each Paper Type
White Kraft Paper (60gsm-250gsm)
- English Name: White Kraft Paper
- Description: A high-grade type of kraft paper mainly used for packaging and tote bags.
- Types: Classified by shade into natural white and high white. Additionally, based on production process and performance, subtypes include high-wet-strength white kraft paper, waterproof white kraft paper, ash-free white kraft paper, and coated white kraft paper.
- Coated White Kraft Paper: Undergoes coating treatment to create a finer and smoother surface, enhancing print quality with vibrant colors. It combines the advantages of coated paper and kraft paper.
Woodfree Paper (70gsm-250gsm)
- English Name: Wood-Free Printed Paper
- Colors: Available in natural white, beige, and high-whiteness (up to 103 CIE). Colored woodfree paper is also available.
- Description: A commonly used printing paper, also known as coated-free paper or book paper.
- Common Uses: Offset paper is widely used for magazines, color pages, product catalogs, maps, calendars, book covers, inserts, illustrations, product manuals, handbooks, comic books, advertising posters, corporate brochures, flyers, envelopes, notebooks, business forms, manuals, office stationery, business cards, colored trademarks, and various packaging materials.
5. Characteristics and Uses of Woodfree Paper
- Woodfree paper is manufactured with sizing agents on both sides to improve surface properties.
- Key advantages:
- Low expansion and contraction.
- Uniform ink absorption.
- Smooth texture.
- High opacity.
- Strong water resistance.
6. Additional Notes on Woodfree Paper
- Standard basis weights: Offset paper generally ranges between 70gsm and 120gsm, but heavier weights such as 150gsm, 180gsm, 300gsm are also available. The most commonly used weights are 70gsm-120gsm.
- Variants: Offset paper can be single-sided or double-sided, and is available in super-calendered and regular calendered finishes.
7. Characteristics and Uses of Woodfree Paper
- Woodfree paper is primarily used for high-quality printing, especially in offset printing presses.
- Since offset printing relies on a water-ink balance, the paper must have good water resistance, dimensional stability, and strength.
- To achieve accurate color reproduction, woodfree paper must have sufficient whiteness and smoothness.
- Woodfree paper is commonly used for brochures, colorful illustrations, trademarks, covers, endpapers, premium books, and notebooks.
