The grade register
Six grades, each with a written qualification specification behind it. The values on this page are the minimums a mill has to meet before we will sell its paper under our name. A grade appears here once a machine has been qualified against it, and not before.
How to read this page
Plenty of mill websites publish a grid of strength figures. Read enough of them and you notice the figures rarely move, whoever the mill is. They are typical values, and a typical value is an average that a given reel is free to miss.
What follows is a different kind of number. Each one is a floor. Paper that fails any applicable requirement is not listed, not quoted and not sold, whichever mill made it and whatever the order is worth. We hold the same line against our own machine near Cali as against everyone else's.
≥ means the result must be at or above the value shown. ≤ means at or below. Water absorption is stated as a maximum, because a lower figure is the better one. Every value is determined under ISO 187 conditions, and all tensile testing is to ISO 1924-3 at 100 mm/min.
| Origin | Valle del Cauca, Colombia |
|---|---|
| Production | Our mill near Cali and qualified partner mills |
| Furnish | Recovered or Virgin fiber as needed |
| Fiber declaration | Actual content stated per shipment |
| Roll width | Slit to your requirement |
| Roll diameter | To suit your unwind stand |
| Core | To your specified internal diameter |
| Formats | Jumbo reels, slit rolls, sheets to order |
| Packing | Moisture barrier wrap, sealed heads, edge protection |
| Documentation | Lot test certificate with every shipment |
Roll dimensions and core sizes are confirmed against the qualified machine at the time of offer. Tell us your unwind stand and we will tell you what we can hold.
01 | MG kraft
Glazed against a Yankee cylinder to give one smooth, printable face. One qualified grade, unbleached.
VK-HOM-MGU-01
Glazed on one side against a Yankee cylinder, left unbleached. The workhorse wrapping grade, where a smooth printable face matters more than color.
| Property | Test method | Requirement |
|---|---|---|
| Burst index (kPa·m²/g) | ISO 2758 | ≥ 3.89 |
| Tear index MD (mN·m²/g) | ISO 1974 | ≥ 7.9 |
| Tensile index MD (N·m/g) | ISO 1924-3 | ≥ 87.5 |
| Tensile index CD (N·m/g) | ISO 1924-3 | ≥ 41.2 |
02 | Sack kraft
Three grades, separated by how much the sheet stretches before it fails. A sack on a fast filling line takes a shock, and the paper either absorbs that energy or tears. Stretch and energy absorption rise across the three, and the price rises with them, so the grade is chosen against your filling speed rather than against your budget.
VK-HOM-SKST-01
Sack paper for ordinary filling speeds. Strength comes from tensile rather than from stretch, which is what makes it the cheapest of the three sack grades to run.
| Property | Test method | Requirement |
|---|---|---|
| Tensile index MD (N·m/g) | ISO 1924-3 | ≥ 93.7 |
| Tensile index CD (N·m/g) | ISO 1924-3 | ≥ 50.1 |
| Stretch MD (%) | ISO 1924-3 | ≥ 2.5 |
| Stretch CD (%) | ISO 1924-3 | ≥ 6.9 |
VK-HOM-SKSE-01
Stretch in both directions, and tear enforced alongside it. The grade for a filling line fast enough that the sack has to absorb the shock rather than resist it.
| Property | Test method | Requirement |
|---|---|---|
| Tensile index MD (N·m/g) | ISO 1924-3 | ≥ 78.4 |
| Tensile index CD (N·m/g) | ISO 1924-3 | ≥ 56.9 |
| Stretch MD (%) | ISO 1924-3 | ≥ 5.9 |
| Stretch CD (%) | ISO 1924-3 | ≥ 7.9 |
| TEA index MD (J/g) | ISO 1924-3 | ≥ 2.8 |
| Tear index MD (mN·m²/g) | ISO 1974 | ≥ 11.9 |
| Tear index CD (mN·m²/g) | ISO 1974 | ≥ 13.3 |
VK-HOM-SKE-01
The highest stretch and energy absorption we qualify. Tear is reported rather than required here, because tear and TEA trade against each other and demanding both at once is a bar no mill clears.
| Property | Test method | Requirement |
|---|---|---|
| Tensile index MD (N·m/g) | ISO 1924-3 | ≥ 80.4 |
| Tensile index CD (N·m/g) | ISO 1924-3 | ≥ 60.5 |
| Stretch MD (%) | ISO 1924-3 | ≥ 8.0 |
| Stretch CD (%) | ISO 1924-3 | ≥ 8.3 |
| TEA index MD (J/g) | ISO 1924-3 | ≥ 3.3 |
| TEA index CD (J/g) | ISO 1924-3 | ≥ 3.2 |
03 | Containerboard
Testliner faces the board and carries the print and the stacking load. Corrugating medium is the fluted layer between two liners and is bought on flat crush. Both are banded by basis weight, because a heavier sheet is expected to carry more and one figure across the whole range would let the light end through too easily.
VK-HOM-TL-01
The facing layer of a corrugated board, made from recovered fiber. Ring crush is banded by basis weight because a heavier liner is expected to carry more, and a single figure across the range would let the light end through too easily.
| Property | Test method | Basis weight (g/m²) | Requirement |
|---|---|---|---|
| Burst index (kPa·m²/g) | ISO 2758 | All weights | ≥ 2.22 |
| SCT index CD (N·m/g) | ISO 9895 | All weights | ≥ 15.3 |
| RCT CD (kN/m) | TAPPI T 818 | 130 to 169 | ≥ 1.36 |
| RCT CD (kN/m) | TAPPI T 818 | 170 to 219 | ≥ 1.85 |
| RCT CD (kN/m) | TAPPI T 818 | 220 to 299 | ≥ 2.53 |
| RCT CD (kN/m) | TAPPI T 818 | 300 and up | ≥ 3.44 |
| Cobb 60 s, top side (g/m²) | ISO 535 | All weights | ≤ 39 |
VK-HOM-CM-01
The fluted layer between two liners. Flat crush is what the grade is bought on, so CMT is banded by basis weight and the water absorption limit is set loose enough that ordinary recovered furnish can reach it.
| Property | Test method | Basis weight (g/m²) | Requirement |
|---|---|---|---|
| CMT (N) | ISO 7263 | 100 to 129 | ≥ 195 |
| CMT (N) | ISO 7263 | 130 to 169 | ≥ 238 |
| CMT (N) | ISO 7263 | 170 to 219 | ≥ 289 |
| Cobb 60 s, top side (g/m²) | ISO 535 | All weights | ≤ 64 |
A technical note
Most published grade data is honest. Some of it was written rather than measured, and the difference is visible from the page if you know where to look. None of what follows needs a laboratory. It needs the sheet read carefully, and it applies to ours as much as to anyone else's.
None of this makes a supplier dishonest. Most of it is a sheet that was written once, by someone who has since left, and never checked against production again. But it does tell you which numbers you can plan a converting line around and which you cannot, and that is worth half an hour before you commit an annual volume.
If you want a second pair of eyes on a technical data sheet, ours or a current supplier's, send it over. We will tell you what it says, what it does not say, and which questions we would ask before putting volume behind it.
Growing the register
This register is short on purpose. A grade is listed once we hold a written specification for it and a machine has been qualified against that specification. Grades we can make but have not yet written a standard for are not here, and neither are grades where the published market data was too thin to set a defensible bar.
Mills across the Valle del Cauca approach us regularly, and each one brings a machine with its own capabilities. If what you need sits outside the six grades above, tell us anyway. There is a reasonable chance it is already in qualification, and if it is not, knowing there is a buyer is what makes us go and find the machine for it.
Ask about a grade| Specification | Written targets and tolerances for your grade |
|---|---|
| Fiber content | Declared composition of the grade offered |
| Sample | Physical samples on request before trial |
| Trial terms | Single container trial, priced for the run |
| Landed cost | FAS or CIF to your port |
| Lead time | Quoted against the current production plan |
We will tell you which of our mills can hold it, or that none of them can.
