Impregnated kraft paper is a deep-processed version of unimpregnated base paper. Manufacturers produce it through impregnation and drying processes, which introduce an adhesive layer between fibers.
This adhesive layer creates a major performance difference. As a result, each type serves different applications and usage scenarios. Below is a clear comparison to help you choose quickly.
I. Core Performance Differences (Most Critical)
Unimpregnated kraft paper maintains its natural hydrophilic properties. It absorbs water and moisture easily, softens when wet, and loses strength rapidly under humid conditions.
At the same time, it offers good air and moisture permeability and relies solely on natural fibers for strength. However, it shows limited resistance to weak acids, alkalis, and heat.
In contrast, impregnated kraft paper seals fiber pores with an adhesive layer. This structure significantly improves water, moisture, and oil resistance, preventing deformation when exposed to liquids.
Moreover, it delivers higher tensile, burst, and abrasion resistance in both dry and wet states. Depending on the adhesive used, it also provides better chemical and heat resistance. However, its air permeability is extremely low, and it absorbs almost no water.
II. Appearance and Processing Adaptability
Unimpregnated kraft paper features a matte surface and visible natural fiber grain. It feels dry and slightly rough, which suits most conventional processing methods.
It prints well, folds easily, cuts cleanly, and bonds without difficulty. Manufacturers can process it using standard equipment, making it highly cost-effective.
By comparison, impregnated kraft paper has a thin adhesive film on the surface. This gives it a smoother touch and slightly higher gloss.
However, conventional printing becomes more difficult and often requires special inks. Folding may leave marks, cutting demands sharper tools, and bonding requires compatible adhesives. Some grades also need dedicated processing equipment.
III. Cost and Environmental Performance
Unimpregnated kraft paper requires no deep processing, so production costs remain low. Its pure fiber structure allows easy recycling and natural biodegradation.
For this reason, it aligns well with sustainable and lightweight packaging trends.
Impregnated kraft paper involves additional impregnation and drying steps, as well as adhesive usage. As a result, its cost typically increases by 30%–100%, depending on adhesive type and dosage.
Its environmental performance depends on the adhesive system. Water-based adhesives allow recycling, while solvent-based systems reduce degradability.
IV. Typical Application Scenarios
Unimpregnated Kraft Paper (Basic & Universal):
Shopping bags, courier bags, carton liners, food inner pads, labels, and bill paper.
It also suits light industrial packaging, clothing protection, printing, and craft uses.
Impregnated Kraft Paper (Reinforced Protection):
Industrial wear-resistant gaskets, waterproof packaging for furniture and building materials, and heavy equipment liners.
It also works well for waterproof paper bags (chemicals, cold-chain goods), electrical insulation, construction formwork liners, and leather reinforcement.
Selection Summary
Choose unimpregnated kraft paper if you prioritize low cost, versatility, and environmental friendliness.
Choose impregnated kraft paper if your application requires water resistance, wear resistance, high strength, or moisture protection—especially in industrial or complex packaging.
Performance can be customized through different adhesive systems.