A Shipping Mailer You Can Recycle Whole Insulation Made From Cardboard That Still Turns Back Into Pulp

This application covers the insulating liner inside a padded shipping mailer, made almost entirely from recycled paper and cardboard fibre held together by a small fraction of melted plastic binder fibre. The point of the construction is that the finished liner can go into a kerbside recycling stream with the box rather than being pulled out and thrown away, because when it is pulped the great majority of it comes back as usable fibre. It was filed by MP Global Products, L.L.C. of Norfolk, Nebraska, and names Alan B. Collison and Reid Borgman as inventors. The application is a divisional of two earlier Australian applications and traces back to United States provisional filings from 2016.

The Problem

The background section of this specification is four sentences long, which is unusually blunt, and the last of them carries the whole argument. Insulated boxes are used widely, they are wanted whenever goods must travel hot or cold or must be protected from temperature swings, and they cushion impact so that a product survives the trip and arrives looking well made. Then: insulating materials are typically made of materials quite unlike those used to make boxes, which makes recycling impossible.

That is the real problem in insulated shipping. A corrugated box is one of the most successfully recycled objects in the consumer economy. The moment you line it with expanded polystyrene, a foil bubble laminate or a polyethylene foam sheet, the package becomes a composite. The recycler either has to separate the two materials by hand, which nobody does at volume, or reject the whole thing. The insulation does not merely fail to be recycled, it contaminates the part that would have been.

That matters more every year because of what is being shipped. Meal kits, chilled groceries, pharmaceuticals and pathology samples all travel in insulated packaging, and all of them arrive at a residential address where the only disposal route is the household bin. Whatever the cold chain requires at the packing end, the householder at the other end has one decision to make and roughly two seconds to make it.

What This Invention Does

Despite a title that promises a method, claim 1 as filed is a product claim. It reads on a repulpable insulation liner comprising a first paper layer, and a cellulose fibre pad coupled to that paper layer, the pad including thermoplastic binder fibres and cellulose reinforcement fibres bound together by the binder fibres, with the reinforcement fibres including at least one of paper fibres and cardboard fibres. There are nine claims and all of them are directed to the liner rather than to making it.

The construction is deliberately simple. Recycled cardboard and paper are ground up, in the described embodiment by passing recycled cardboard through a hammer mill, and mixed with a small quantity of bicomponent binder fibre distributed randomly through the mass. The mixture is laid onto a moving conveyor between tapered edge plates that set the width and uncompressed thickness, adjusted with a compression roller, and then heated in an oven above about 350 degrees F, preferably around 362 degrees F. The binder fibres melt, bond to the surrounding paper fibres, and on cooling solidify into a network that both holds the pad together and reinforces it. The result is a low density batt, which can be sliced in half along its thickness to yield two pads.

The dependent claims put a shape on the material. Claim 2 keeps the binder below about ten per cent by weight of the pad. Claim 3 sets a minimum thickness of about one sixteenth of an inch. Claim 4 gives the pad a basis weight between 1000 and 1600 GSM. Claim 5 keeps the average binder fibre length under about 16 mm. Claim 6 lists the binder options, bicomponent fibres or fibres of polyvinyl alcohol, polyethylene, polyester, polypropylene or mixtures. Claims 8 and 9 add a second paper layer, on the opposite face of the pad from the first, which is the envelope that becomes the mailer.

The numbers behind the claim are in the body. A preferred mix is about ninety per cent recycled cardboard fibre to ten per cent bicomponent fibre, the bicomponent being a polyethylene and polypropylene fibre at roughly a 65 to 35 ratio. Tested against the repulpability protocol, a 1300 GSM sample at that ratio, using a blend of one millimetre and six millimetre binder fibres, returned fibre yields of 93.5 and 93.2 per cent with no deposition observed on the vessel walls or screens. A sample using only one millimetre binder fibre returned over 98 per cent. The specification treats 85 per cent as the passing grade for recyclability.

Assembly of the mailer itself is described in ordinary manufacturing terms. An inner paper layer is draped over the pad, overlapping on all four sides with the ends tucked under, and fixed with heat or a water soluble adhesive. The subassembly is folded, the sides closed to form a pocket, and the edges sewn shut on an industrial sewing machine with two rows of stitches. An outer paper layer is then wrapped around the outside so that it forms a closable flap, sealed with a double sided tape that is itself recycling compatible.

Key Features

• Binder fibre instead of glue or lamination. The pad holds together because a small percentage of thermoplastic fibre is melted through it, so there is no adhesive layer or film to separate out later.
• A tested repulpability figure, not a claim of recyclability. The specification reports actual fibre yields of 93.2 to over 98 per cent against the industry screening protocol, measured on stated sample weights with rejects and accepts weighed oven dry.
• Cardboard as the feedstock. The reinforcement fibre is ground recycled cardboard and paper, described in the body as fiberised at ratios from about 50 to 50 up to about 75 to 25 cardboard to paper, so the material is made from the waste stream it is designed to re enter.
• Slicing one batt into two pads. The formed batt can be cut along a horizontal plane with a rotating band or circular blade, producing two pads of different thickness from a single forming line.
• Measured insulating performance. The specification reports a thermal conductivity of about 0.0366 W per m K and an R value of about 1.577 when tested to ASTM C518-15, alongside compression and tear figures for a half inch pad.
• Water soluble adhesives and stitching throughout. Where the paper layers are joined to each other or to the pad, the specification specifies heat, stitching or recycling compatible and water soluble adhesive, keeping the whole assembly within one recycling stream.

Who Is Behind It

MP Global Products is a family owned manufacturer based in Norfolk, Nebraska, founded by Al Collison and run since by the Collison family. Its core business is thermally bonded non woven material made from recycled fibre, best known through the QuietWalk flooring underlayment line, and the same forming technology underpins the packaging products at issue here. The company has, as its own material puts it, been innovating with recycled materials for nearly three decades.

The specification also records a joint research agreement. Paragraph [0003] states that the claimed invention was made under an agreement between MP Global Products LLC of Norfolk and Pratt Retail Specialties, LLC of Conyers, Georgia, in effect on or before the effective filing date. Pratt Retail Specialties is part of Pratt Industries, one of the larger corrugated packaging groups in the United States, which is a logical partner for a liner intended to be sold inside a box.

One piece of context worth recording alongside the filing. In August 2026, five months after this divisional was lodged in Australia, MP Global announced the sale of its Packaging Division to new ownership, saying it would continue as a family owned flooring underlayment and building materials manufacturer. The Packaging Division continues under the new owner. Nothing in the Australian file wrapper reflects that, and the applicant of record remains MP Global Products, L.L.C.

The priority position is set out clearly at the head of the body text. The application claims the benefit of United States utility application 15/677,738 filed 15 August 2017, and of two United States provisional applications, 62/419,894 filed 9 November 2016 and 62/437,365 filed 21 December 2016. It is divided from Australian applications 2017359035 and 2021245201. The priority country is the United States and the earliest priority date is November 2016, close to a decade before this filing.

Why It Matters

Repulpability is a specific and testable property, and that is the interesting part of this specification. The document does not simply assert that the liner is recyclable. It names the standard, the August 2013 revision of the Voluntary Standard for Repulping and Recycling Corrugated Fiberboard Treated to Improve Its Performance in the Presence of Water and Water Vapor issued by the Fibre Box Association, and reports test sheets with the moisture content, charge weight, slurry temperature, reject mass and accept mass filled in. That standard has since been updated, and the current joint AF&PA and FBA voluntary standard covers coated or treated corrugated in the old corrugated container recycling stream, but the principle is the same: a mill needs to know that what arrives will yield usable fibre and will not gum up the screens.

That last point is why the deposition line in the test table matters more than it looks. A binder that survives pulping as sticky fragments does not just reduce yield, it fouls the equipment and contaminates the paper made from the batch. Reporting no deposition observed on vessel walls, screens or moving parts is the claim that the ten per cent of plastic in this material behaves itself, and it is the technical reason a fibre pad with polyethylene in it can be treated as paper rather than as a composite.

The commercial logic follows from the disposal end rather than the packing end. An insulated mailer competes with foil laminates and foam on thermal performance and cost, and on those measures a cardboard fibre pad is respectable rather than exceptional. Where it wins is that the householder can flatten the whole thing and put it in the paper bin without making a judgement call. Given how much chilled food and how many pharmaceuticals now arrive at residential addresses, designing the packaging around what happens after delivery is arguably the more consequential engineering decision.

Related Concepts

• Paper recycling – the waste stream the liner is designed to enter intact rather than contaminate.
• Pulp) – the fibre slurry the repulpability test measures the liner’s yield into.
• Insulated shipping container – the product category the claimed liner is built for.
• Nonwoven fabric – the thermally bonded web technology the pad is formed by.
• Polystyrene – the incumbent foam insulation the specification is implicitly written against.

---

AU 2026202145 was published in the Australian Official Journal of Patents on 9 April 2026 and is open for public inspection. Patent applications represent inventions that are sought to be protected and do not necessarily reflect commercially available products.