This page describes the Primaloft insulating material we currently consider is the optimal choice for making the insulating jacket. I was led to consider this material by an interesting article on the Internet which compared various different fiber insulation materials, of which there are a bewildering variety such as "Polarguard", "Hollofil", "Quallofil", "Microloft", "Liteloft", "ExceLoft", etc.... made by various manufacturers such as Dupont, Teijin, etc.... In fact all insulating fiber materials, even ones made from fibers of the same average diameter, are not by any means created equal as far as insulation performance is concerned. The overall recommendation of the article, which was from the viewpoint of insulation material for sleeping bags, was for Primaloft if cost was not a dominant issue; unfortunately, I can no longer find the reference.

The Primaloft material is made by Albany International of Albany, N.Y.. You can refer to the Primaloft home page on their website, and to this page which recounts the benefits of Primaloft. And microphotographs of Primaloft and several competing products can be seen here.

Moreover, Albany International are the proprietors of a number of interesting patents relating to synthetic down and associated products, which I assume are Primaloft-related. Particularly, I have studied the following US Patents:

4,588,635 - Donovan - "Synthetic Down"
4,681,789 - Donovan et al. - "Thermal Insulator Comprised of Split and Opened Fibers and Method for Making Same"
4,992,327 - Donovan et al. - "Synthetic Down"
5,043,207 - Donovan et al. - "Thermally Insulating Continuous Filaments Materials"
5,798,166 - Gross - "Insulation for Sleeping Bags and Similar Items"

and have learned more about synthetic down-replacement materials than one might think possible!

If you want to get the texts of these patents, you can download it from the US Patent Office here.

Primaloft PL1 (the highest quality) is made in three grades of different thicknesses:

Nominal 1/2", 3 oz/yd2 . . . . . i.e., 100 gm/m2
Nominal 5/8", 4 oz/yd2 . . . . . i.e., 133 gm/m2
Nominal 1", 6 oz/yd2 . . . . . i.e., 200 gm/m2

Moreover, it can either be supplied in the raw form, or pre-quilted with very light batting on both sides. This pre-quilted version is sewn longitudinally in lines 15 cm apart. Here is a sectional view:

This pre-quilted version is obviously much easier to handle, but we have our reservations about it; see comments elsewhere ....

Anyway, we have obtained samples of the three Primaloft PL1 grades for making test insulation jackets..... Our security guard immediately gave the product his vote - he knows very well what is warm and soft and springy (i.e., lofty) and what isn't.....

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