Kraft liner paper: Sustainable packaging made from renewable woods 

Sustainable and durable packaging for food as well as other goods, which in addition do not contain toxic pollutants, are an illusion? - Take a look at our high-quality kraft papers and let us convince you otherwise. They are made from renewable, regional raw materials and are produced in an environmentally friendly way.

What is kraftliner paper and what is it made of?

The term "kraft liner paper" refers to a particularly robust, tear-resistant special paper used for the production of paper sacks, bags and shopping bags, shipping bags as well as paper adhesive tape or emery paper.

It is the paper with the highest possible strength and is therefore also used to stabilize corrugated board or simple cardboard. Outer and inner liner made of kraft liner, also called wood paper, make cardboard transport packaging resistant and tear-proof.

Kraftliner consists of at least 80 percent long fresh fibers from slow-growing conifers from northern regions. Mostly resin-rich wood species such as fir or pine are used. Their wood chips, to which straw can also be added, are boiled under pressure for several hours in a sulfate-containing lye.

In this process, the wood fibers are broken down into pulp without damaging the fibers. This is the reason for the high strength of Kraftliner paper. Its basis weight, the grammage, is 120 gr per square meter.

In addition to the cellulose fibers, the macromolecule lignin contained in the plant cells is released, which is responsible for the brown color of kraft paper. Unlike other types of paper, kraftliner paper retains its brown color and is not bleached. Bleaching would be detrimental to the strength of the paper.

Kraft liner paper is a robust special paper made from fresh long fibers of resin-rich conifers. It is produced in an environmentally friendly way and is mainly used for the production of bags, sacks and mailers.

Recognition characteristics and manufacturing process

This is how you can safely recognize Kraftliner paper:

• Kraft papers are robust, do not tear even when crumpled and can withstand even impact stress in bulging paper bags without major damage.
• They have no waste paper content and are therefore darker in color than Schrenz or Testliner paper, with the shading depending on the type of wood used in their manufacture.
• If you tear kraft liner paper at a slight angle, you can clearly see the long brown fibers that provide strength and stability.

Our kraft paper proves that the production of high-quality and robust papers can be sustainable and environmentally friendly.

The sulfate process is used, which is often also referred to as force digestion.

The cells of wood chips are split using caustic soda. The result is paper pulp whose strength increases proportionally with the fiber length of the wood used.

The sustainability of the production process is supported by the fact that the sulfates used can be extracted and reused after the cooking process.

Although kraft paper is produced with no or only a very small amount of waste paper, it can be recycled very well because of its long fibers.

Special forms of kraft papers are:

• creped kraftliner papers with additional high extensibility
• Kraft silk - a frequently ribbed, very thin kraft liner paper with a basis weight of less than 30 g per square meter, used to wrap delicate materials such as glass or silver
• for special purposes, kraft papers are available coated with plastic or bituminized (bitumen = naturally occurring or petroleum-derived tar-like mass used, among other things, as a sealing and insulating material).

Advantage I of the material: Extreme resistance

Reliable, resistant and tear-proof - kraftliner paper scores with a variety of positive mechanical properties. The long-fiber pulp made from Nordic wood delivers what its name promises. The preferred use of fresh fibers and the fact that the wood pulp is not bleached make the material extremely resistant.

You will look in vain for fillers, which are a not insignificant component of graphic papers, in kraftliner papers. They would considerably reduce the porosity of the papers and thus their air permeability. Residual air would remain in envelopes and paper sacks after sealing and negatively influence their stability.

Another secret for the robustness of kraft paper is the process of grinding the pulp. During this process, the fibrils (microscopic fiber strands) are separated. The correct duration of the refining process is crucial: while the fibrils initially crosslink and provide additional stability, this positive effect is reversed if refining takes too long.

Resistance of kraftliner paper at a glance:

• High burst strength
• high tear and tear propagation resistance
• High crush resistance

But these are by no means all the advantages of this special paper variant. There are more to come!

Advantage II: Good to print

Kraft liner paper has a very smooth, closed surface. This makes the material conditionally water-repellent and does not soak through so quickly when wet.

The clean, smooth surface is also highly appreciated by marketing experts. It is ideally suited for printing. This means that paper bags for the supermarket can be easily provided with graphics and advertising messages - even shipping bags and paper sacks with company logos of any kind.

The closed material surface also guarantees easy further processing of the paper, such as folding (producing a sharp folded edge) and gluing. Positive effect for envelopes: Adhesive strips of all kinds adhere particularly reliably to the smooth surface of Kraftliner paper.

Kraftliner and sustainability

The multiple reusability of the caustic soda required for the production of kraft paper, as well as the use of resin-rich softwoods native to Europe, are the first indications of the sustainability of kraft paper production.

Another plus point is the fact that kraftliner paper can be easily recycled after use. The prerequisite for this is the long virgin wood fibers of the base material. Since it consists almost entirely of natural cellulose, the paper is almost completely biodegradable.

The absence of artificial fillers also ensures that microorganisms can easily decompose the robust material. Organisms have more difficulty with kraft paper, which is coated with a thin plastic film for greater water resistance.

Another aspect for the sustainability of kraftliner paper is the energy balance of its production. On the one hand, sulfate processes, recovery of the caustic soda and other manufacturing processes are indeed energy and water intensive. However, innovative processes generate energy-rich black liquor during recovery of the chemicals used. The energy obtained from it can be used to dry the paper.

These properties make kraftliner paper particularly environmentally friendly:

• sustainable raw materials from domestic regions - pines, firs; wood is a renewable, CO2-neutral raw material; avoidance of exotic woods
• Environmentally conscious manufacturing processes with reuse of used chemicals
• Multiple use due to extreme robustness, fully recyclable.

Possible uses and applications of kraftliner paper

The resistance and robustness of the material make kraftliner papers versatile. Paper bags - printed or unprinted - are indispensable utensils for retail and hospitality. Even the handles of kraft paper bags survive transport undamaged.

Bags with reinforced, so-called American bottom are available in all imaginable sizes and belong to the indispensable assortment of every supermarket.

DoypacksThese sturdy bags made of kraft liner paper are often coated on the inside and are ideal for preserving foodstuffs.

Another wide range of applications for kraft paper are Shipping bags in all designs and sizes. Lined or unlined - shipping bags made of kraft liner are very robust and therefore also ideally suited for shipping delicate and sharp objects.

Sustainable adhesive strips or rolls made of kraft paper have long been able to stand up to comparable products made of plastic and are enjoying growing popularity.

Finally, kraftliner is used as a cover paper of cardboard boxes of various designs.

Use of kraftliner paper at a glance:

• Bags and pouches in all designs and sizes for supermarkets, trade and gastronomy
• coated bags for food preservation
• strong, tear, burst and crush resistant paper bags for various purposes
• Shipping bags of all sizes, lined or unlined, printed or plain
• Adhesive tape
• Wrapping paper
• Construction paper
• Emery paper
• Cover paper for stabilization of cardboard boxes

What is the difference between kraftliner and kraftliner paper?

Kraft liner paper consists almost exclusively of long fresh fibers of resinous wood. No waste paper is added to the pulp, which gives the paper its special strength and stability. Its grammage is no more than 120 g per square meter.

The basis weight of kraftliner, on the other hand, can be up to 430 g per square meter, and up to 20 percent recovered paper can be added to the cellulose pulp. The coarser kraftliner is used primarily in the manufacture of cardboard boxes.

FAQ

1. What is kraft liner paper?
   A very strong, tear-, burst- and impact-resistant specialty paper used to produce reliable, reusable packaging items for personal and commercial use.

2. What is kraft paper made of?
   Kraft liner paper consists of finely ground chips of resin-rich woods such as fir or pine. During paper production, the long wood fibers remain intact and give the paper particular strength and elasticity.

3. What products are made from kraft liner paper?
   Kraft paper is used for the production of high-quality and robust bags, bags - with and without handles - sacks as well as shipping bags. Adhesive strips, emery, packaging and craft papers can also be made from this reliable and sustainable paper variant.
   
   

Can all these facts and backgrounds convince you of this innovative and environmentally friendly material? If you still have questions, please feel free to contact us! We are here for you and will gladly assist you with words and deeds.