Kraft Liner Board is the strongest type of cardboard in the field of transportation packaging, mainly used for making corrugated cardboard boxes for foreign trade packaging and high-end product packaging. It is also known as kraft paper or face hanging cardboard, which is tougher and firmer than ordinary cardboard. According to color, it is usually divided into two categories: brown and light; According to the quality level, it is divided into three levels: excellent product, first-class product, and qualified product.

Raw materials and processes

Due to differences in the distribution of global timber resources, there are two mainstream paths for raw material ratios:

Abroad (traditional wood pulp type): 100% natural sulfate wood pulp is often used, or only wood pulp is used as the surface and waste paper pulp as the core and bottom layer.

Domestic (mixed pulp type): Due to insufficient wood resources, 40% to 50% wood pulp is usually used for surface coating, while mixed pulp such as wheat straw pulp, waste pulp, or bamboo pulp is used for the core and bottom layers.

In terms of craftsmanship, the top and bottom slurries are usually treated separately, and then processed through mesh forming, pressing, drying, sizing, and calendering to produce the final product. The key requirement for adhesive strength is generally to reach 0.75mm or above to ensure moisture and water resistance.

Technical indicators and specifications

The main technical indicators revolve around strength and water resistance:

Tightness: not less than 0.68 g/cm ³

Durability index: not less than 2.60 kPa · m ²/g

Lateral ring pressure index: not less than 7.5 N · m/g

Lateral bending resistance: not less than 60 times

The conventional weight range is relatively wide, commonly ranging from 115 to 360 g/㎡, while mainstream products in the market are mostly concentrated at 170 to 300 g/㎡. The common widths of roll paper include 940mm, 1930mm, 1940mm, and other specifications.

Characteristics and Applications

Core features: extremely high compression resistance, puncture resistance, and bending resistance, as well as good moisture resistance and excellent appearance quality.

Main use: As a high-end cardboard used in the manufacturing of foreign trade packaging boxes and domestic high-end product packaging boxes (such as high-end electrical appliances, precision instruments, tobacco and alcohol, etc.), it is a premium cardboard used in transportation packaging.

Overall, Kraft Liner Board, as a high-strength surface paper material in the field of transportation packaging, plays a key role in protecting goods and improving packaging quality. From raw material ratio to adhesive and calendering process, every technical indicator directly affects the compressive, moisture-proof, and durability performance of the finished box. With the continuous development of e-commerce logistics and foreign trade exports, the demand for Kraft Liner Board is also steadily increasing, and there is still significant room for optimization in the direction of lightweight, high-strength, and environmentally friendly recycling in the future. For packaging companies, choosing the appropriate weight and grade based on specific purposes is necessary to achieve the best balance between cost and protective performance.