If you manufacture high-pressure laminate (HPL), you are already aware of how vital each component is to the finished product. Although the ornamental surface is what catches most of the attention, it is the saturating kraft paper beneath that does most of the work.

Selecting the right saturating kraft paper requires uniformity, material integrity, and performance that withstands the heat, pressures, and time. When you are sourcing one to be used on your production line, here are some of the things that you should be thinking about.

Understand its role

Your laminate is saturated at its core with kraft paper, between the decorative paper and a resin. Its core business is to evenly absorb the resin, cure effectively under load, and produce a good, dense product after pressure.

When your kraft paper is difficult to saturate or has inconsistent density, you will know it. Not necessarily immediately, but later on through weak areas, warping, or delamination. At that point, it costs much more to repair.

Focus on resin absorption and holdout

This is probably the most important aspect. You want a sheet that will absorb resin perfectly. Not too much of it, nor too little. Too much and you are wasting resin and inflating the cost. Not enough, and you get bad bonding and weak panels.

When inspecting samples, ask your saturating kraft paper supplier about the following:

  • Saturability tests
  • Porosity and permeability
  • Uniformity of fiber structure.

If you change resin systems, e.g., switching from phenolic to hybrid or melamine blends, consult your paper supplier as early as possible. Kraft papers do not perform equally in different chemistries.

Verify basis weight and sheet uniformity

Everything works better when there is consistency in high-pressure laminate lines. Basis weight, thickness, or sheet thickness variation can interfere with your resin circulation, press cycle, or even panel thickness.

Find a paper that provides:

  • Strict basis weight tolerances
  • Good machine direction and cross-direction strength
  • Consistent sheet material production to minimize weak points.

These are minor details that matter a lot once you are operating at scale.

Consider end usage

All laminates are not created equal, and neither are the papers behind them. Are you printing compact laminates on outdoor signs? Ornamental cabinetry surfaces? Heavy-duty panels for lab benches?

Depending on the application, you may require:

  • Stronger density kraft
  • Thinner panels on lower porosity paper
  • Certified fiber sourcing/fire-resistant grades for regulated industries.

The better you understand the end use, the more effectively you can align the kraft paper with its intended purpose.

Collaborate with your supplier

Ultimately, choose a reliable saturating kraft paper supplier. One who takes the time to understand your process.

There is nothing wrong with requesting technical data, sample rolls, or even mill trials. A quality supplier will assist you in fine-tuning the correct spec, solving problems, and modifying as your laminate lines grow.

The bottom line

With HPL, it is all about the core. The overarching rule to remember here is that selecting the right saturating kraft paper in the initial stage will lead to an easier production process and high-quality laminates. Invest the time to get it right, and your customers will appreciate it.