Rubberized roof underlayment

Abstract

An underlayment product comprises a fibrous mat having an upper surface and a lower surface. A rubberized asphalt coating is applied to the lower surface of the fibrous mat and extends at least partially into the fibrous mat. An oxidized asphalt coating is applied to the upper and lower surfaces of the fibrous mat generally encapsulating the fibrous mat including the rubberized asphalt coating provided on the lower surface of the fibrous mat. The oxidized asphalt layers may be coated with a release layer such as talc, granules or a polymer.

Description

TECHNICAL FIELD [0001] The present invention relates to roof underlayments and more particularly, to a heavyweight, underlayment product which utilizes a rubberized asphalt layer. BACKGROUND INFORMATION [0002] An underlayment material is commonly used in a number of roofing applications as well as other underlayment situations. The typical product utilized in roofing underlayment is commonly referred to as “tar” of “felt” paper. The traditional “tar paper” is an asphalt impregnated paper product which is sold in a roll; unrolled on a roof; cut to length; and fastened to the roof utilizing staples or nails. Although tar paper is inexpensive, it does not seal nail holes through the paper and thus does not prevent water infiltration. In addition, once the felt is rolled out, it absorbs water and once wet, it wrinkles and expands, and must be allowed to dry out before covering with shingles. Other prior art shingle underlayment products also suffer from the same problems. [0003] Accordi...

AI Technical Summary

Benefits of technology

[0004] The present invention features a novel underlayment product which will be relatively inexpensive and replace prior art products such as “tar paper” or “felt paper”. The present invention provides an underlayment product with a top surface that can be walked on and will not slide under foot, and wherein the product will not stick to itself or the roof. In addition, the present invention has “cold” flow properties which allow it to “repair” or “heal” itself to thereby reseal around nail or puncture holes and also elongate and recover around punctures.

[0008] In the preferred embodiment, the rubberized asphalt coating which is applied from the bottom of the mat and partially or fully infiltrates the fibrous mat includes approximately 48% flux asphalt, 2% radial SBS rubber and 50% filler material while the fibrous mat includes fibers selected from the group consisting of polyesters, polypropylenes and fiberglass. The coating may, however, be provided having a range a ingredients including, but not limited to 0.5% to 12% radial or linear rubber or polymer; 0-70% filler; and 48-98% asphalt including 0-70% oxidized asphalt. The filler affects the walkability of the outer surface. If the filler content is too low such that a higher asphalt percentage exists, the product would be sticky. The high filler content and / or talc layer prevents sticking. In addition, the filler also brings down the price of the finished product.

[0009] Adding an oxidized asphalt layer on both the top and bottom layer of the mat makes the product more usable in hotter conditions providing a higher resistance to softening by providing an asphalt with a higher Ring and Ball softening point temperature. It also makes the product not stick in three ways: 1) foot traffic 2) the roof deck and 3) in the roll form.

[0011] In the preferred embodiment, the talc coating is suspended in a water-based, polymer emulsion. Examples of the polymer include styrene, acrylic and the polyurethane. When it dries, the polymer forms a film which helps hold the talc to the asphalt so that the talc does not fall off or interfere with any overlap or bonding areas. Loose talc is a slip problem. Although a talc acrylic layer is preferred as the method to prevent sticking, a water or other based polymer may be applied and may be sufficient, as would be a plastic film.

Problems solved by technology

Although tar paper is inexpensive, it does not seal nail holes through the paper and thus does not prevent water infiltration.

Other prior art shingle underlayment products also suffer from the same problems.

If the filler content is too low such that a higher asphalt percentage exists, the product would be sticky.

In addition, the filler also brings down the price of the finished product.

Loose talc is a slip problem.

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