Is Kraftliner Suitable for Long-Distance Shipping?
Corrugated boxes made with kraftliner are suitable for long-distance shipping, provided the right specifications are selected. Long journeys often involve repeated handling, stacking, and changes in temperature and humidity. Choosing a suitable liner is therefore necessary, but it does not alone guarantee product protection.
To make an effective choice, businesses need to assess paper strength, box construction, and transport conditions. This article explains these criteria and discusses when to consider kraftliner or testliner.
What Is Kraftliner, and What Role Does It Play in Corrugated Boxes?
Kraftliner is a paper used as the liner of corrugated board and is typically made primarily from virgin fibers. It provides a flat surface and contributes to the strength and protective performance of the packaging.
Liner and fluting differ in their position and function. Liners form the flat surfaces, while fluting is the corrugated layer between them, contributing to the board’s stiffness and cushioning properties. These components must work together to form an effective packaging structure.
This article evaluates corrugated boxes made with kraftliner, rather than suggesting that a single sheet of kraftliner can protect every type of product.
Why Is Kraftliner Suitable for Long-Distance Shipping?
Paper Strength Helps Protect Goods During Handling
Bursting strength and tear resistance help assess how paper withstands forces that could damage packaging. Bursting strength indicates the pressure the material can withstand before rupturing; tear resistance indicates its ability to resist the propagation of an existing tear.
Paper with appropriate properties can help limit bursting and tearing during repeated handling. However, sharp product edges or strong impacts can still cause damage without additional protection.
Bursting strength and tear resistance help assess paper’s ability to withstand forces that could damage packaging.
It Contributes to a Box Structure That Meets Stacking Requirements
The kraftliner, fluting, and adhesive bonds together form the load-bearing structure of corrugated board. Liner quality therefore influences the box’s performance.
Compression resistance must be evaluated at both the board and finished-box levels. Stacking capacity cannot be determined solely from the paper’s name or grammage.
Specialized Grades Are Available for Demanding Transport Conditions
Specialized kraftliner grades are available for humid environments or applications requiring greater protection. For example, SCA developed Kraftliner Wet Strength for high humidity, fluctuating temperatures, and prolonged storage.
Wet strength and resistance to water absorption are different properties. The former concerns retaining strength when wet; the latter concerns how much water the material absorbs. Not all kraftliner should be assumed to be waterproof.
When Is Kraftliner Alone Insufficient to Protect Goods?
Kraftliner is insufficient when the risks exceed the capabilities of the selected packaging structure, for example:
- Heavy goods or high stacking loads exceed the box’s compression resistance.
- Packaging faces prolonged humidity or contact with water.
- Fragile or scratch-sensitive goods lack suitable cushioning.
- Box design, gluing, creasing, or packing methods are unsuitable.
Paper selection must go hand in hand with packaging design and finished-pack testing. Upgrading the liner does not automatically correct every weakness in a box.
How to Select Kraftliner for Long-Distance Transport Packaging
Determine the Load, Dimensions, and Product Characteristics
The first details to establish are the weight per box, product dimensions, and susceptibility to damage. Products with sharp corners, scratch-sensitive surfaces, or fragile components require particular consideration.
The expected stacking height and duration must also be defined. A bottom box supporting a load for an extended period has different requirements from one stacked briefly during delivery.
Assess the Transport Route and Storage Conditions
The transport route determines which risks the packaging must withstand. Businesses should specify whether goods will travel by road, sea, or a combination of transport modes.
Storage duration, the number of transfers, and moisture exposure should be discussed with the supplier. Similar distances do not necessarily mean similar protection requirements.
Choose the Appropriate Paper Grade and Corrugated Construction
Paper grade should be selected alongside grammage, technical properties, flute type, and the number of layers. Heavier paper does not automatically produce an optimal solution if the other components are unsuitable.
No single grammage or 3-, 5-, or 7-layer construction suits every order. The solution should be based on operating requirements and sample-testing results.
No single grammage or 3-, 5-, or 7-layer construction is suitable for every order.
Check Specifications and Test Before Use
Paper, corrugated board, and finished-box properties describe different levels of packaging performance. When discussing specifications with suppliers, clearly identify the material or package being tested and the test method.
| PropertyTest SubjectMeaning | ||
| Bursting strength | Paper or corrugated board, depending on the test | Ability to withstand pressure before bursting |
| Cobb water absorption | Paper or board surface | Amount of water absorbed within a specified time |
| ECT | Corrugated board | Edge crush resistance |
| BCT | Finished box | Box compression resistance |
FEFCO distinguishes board tests from packaging tests, including box compression, drop, and vibration testing. Businesses should test samples under anticipated operating conditions before placing them into large-scale use.
Kraftliner or Testliner for Long-Distance Shipping?
Kraftliner and testliner should be compared as part of packaging solutions that meet the same product-protection requirements. Testliner is made primarily from recycled fibers, while kraftliner generally contains a higher proportion of virgin fibers. However, the paper name cannot replace grade-specific technical data.
| CriterionKraftlinerTestliner | ||
| Strength requirements | Worth considering for demanding applications; the grade must be checked | Can meet requirements with the right grade and box construction |
| Environmental conditions | Specialized grades are available for demanding conditions | Performance under actual environmental conditions must be checked |
| Paper grade | Compare TDS, grammage, and additional properties | Compare TDS, grammage, and quality consistency |
| Cost | Evaluate the complete packaging solution | Can be economical if performance requirements are met |
Kraftliner should not be considered universally superior, nor should testliner be ruled out for long-distance shipping. The right choice meets the technical requirements at a reasonable total cost.
It should not be assumed that kraftliner is always better or that testliner is unsuitable for long-distance shipping.
Conclusion — Select Kraftliner According to Actual Transport Conditions
Kraftliner is suitable for long-distance shipping when the right paper grade is combined with an appropriate box construction. Three factors must be assessed together: product characteristics – transport journey – packaging structure.
Businesses can provide Protus Paper Supply with their application requirements, grammage, paper width, and technical specifications to discuss a suitable supply solution.