Method of making a sheet of building material

a building material and building sheet technology, applied in the field of building materials, can solve the problems of requiring a substantial amount of labor in their installation, slate is a brittle material, can be cracked or broken rather easily, and is, however, very expensive, and achieves the effects of moderate weight, less expensive, and weather resistan

Inactive Publication Date: 2015-05-07
G R GREEN BUILDING PRODS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The method produces a sheet material that is fire-resistant, durable, and ductile, capable of withstanding weathering and foot traffic, while incorporating higher levels of recycled HDPE and using cost-effective production methods, addressing the limitations of previous synthetic materials.

Problems solved by technology

It is, however, very expensive and as a result is normally used for roofing in only the most expensive houses and in other structures where the increased cost can be justified.
Slate is a brittle material and can be cracked or broken rather easily.
Natural slate tiles are quite durable; however they require a substantial amount of labor in their installation and can break on impact.
They are inherently fragile and suffer much breakage during shipping and installation.
They are fragile even after installation on the roof and can be damaged by foot traffic on the roof.
Slate tiles tend to be excessively heavy and dangerous in earthquakes and high winds, and will fall through the roof in the event of a fire.
Since the tiles are so heavy, they are also expensive to ship.
Also, due to the weight of natural slate, extra structural support is required for slate roofs compared to cedar shake or shingle roofs or asphalt roofs.
Wood shakes and shingles are subject to breakage, rot and loss of coloration.
Their cost is relatively high and they are labor-intensive to install.
Furthermore, wood shakes and shingles can be relatively heavy and are flammable, porous and cannot withstand relatively high wind velocity.
A disadvantage of wooden shakes and shingles is that they absorb moisture and swell.
Because of the propensity of wooden shakes and shingles to absorb water, with time they tend to curl and not remain flat on the roof.
However, they have not, in general, been fully acceptable in terms of performance because they often do not meet all the requirements desired for roofing applications.
As an example, synthetic roofing materials typically have high concentrations of plastic or rubber content in the formulation that directly effects the fire resistance of the products because plastic and rubber materials lack fire resistant properties.
In some case, fire resistance of the product has been enhanced by adding a high concentration of flame retardant, which in turn, makes the product much more expensive.
Products with recycled rubber may also have a strong odor on warm days due to the gassing off of volatile components.

Method used

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  • Method of making a sheet of building material
  • Method of making a sheet of building material
  • Method of making a sheet of building material

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0044]A composition was made comprising about 80% by weight limestone of 100 mesh, 18% by weight polyethylene (13.5% by weight recycled HDPE flakes and 4.5% by weight virgin LLDPE) and 2% by weight of lubricants (zinc stearate or stearic acid). The mixture was made, kneaded and formed into a sheet at about 300-325 degrees F. (149-163 degrees C.). Sample #1 of this preparation was allowed to cool to a surface temperature of about 210-220 degrees F. (99-104 degrees C.) and was strained at that temperature by calendering rollers. Sample #2 of this preparation was allowed to cool to ambient temperature of about 70 degrees F. (21 degrees C.) and was strained at that temperature by calendering rollers. Sample #3 of this preparation was simply allowed to cool to ambient temperature and was not strained.

[0045]The samples were tested for brittleness and ductility as follows. Samples of about 4.5 inches (11.4 cm) in length, 1 inch (2.54 cm) in width and 0.25 inches (6.4 mm) in thickness were ...

example 2

[0048]The effect of having increased levels of limestone in sheet material made from a mixture of polyethylene and limestone was studied. Samples A to D were prepared having the following compositions:

[0049]Sample A: 52% limestone, 46% polyethylene (of which three-quarters is recycled HDPE and one-quarter is virgin LLDPE).

[0050]Sample B: 60% limestone, 38% polyethylene (of which three-quarters is recycled HDPE and one-quarter is virgin LLDPE).

[0051]Sample C: 71% limestone, 27% polyethylene (of which three-quarters is recycled HDPE and one-quarter is virgin LLDPE).

[0052]Sample D: 80% limestone, 18% polyethylene (of which three-quarters is recycled HDPE and one-quarter is virgin LLDPE).

[0053]Each sample composition was kneaded at about 300-325 degrees F. (149-163 degrees C.) and formed into a sheet. No straining of the sheets, as by calendering, was carried out. The sample sheets (having dimensions the same as in Example 1) were tested for brittleness and ductiblity using a three-poin...

example 3

[0055]The effect of straining at 220 degrees F. (104 degrees C.) of sheets made with different levels of limestone filler was studied. Samples A to D were prepared having the same compositions as in Example 2. They were made and kneaded about 300-325 degrees F. (149-163 degrees C.) and formed into sheets. They were allowed to cool to a surface temperature of about 220 degrees F. (104 degrees C.) and were strained at that temperature by passing them through calendering rollers. The four samples were tested for brittleness and ductility according to the method described in Example 1. The results are summarized in FIG. 3.

[0056]The results show that all samples regardless of the level of mineral filler exhibited ductile behavior.

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Abstract

A method of making a sheet of building material, useful for roofing or siding applications, and the sheet material made by such method. A mixture of a thermoplastic resin and mineral filler is prepared, the resin comprising about 10% to 40% by weight of the mixture and the filler comprising about 60% to 90% by weight. The mixture is mixed at a temperature above the melting point of the resin and is formed into a sheet at such temperature. The sheet is allowed to cool until the surface is at a temperature below the midpoint of the melting range of the thermoplastic resin, e.g. in the range of 205 to 225 degrees F. for polyethylene, at which point it is strained by passing it through calendering rollers. The sheet material made by this process, having a high concentration of mineral filler, is fire resistant, durable, ductile, of moderate weight and resistant to weathering. It can be produced using relatively inexpensive manufacturing equipment. The sheet material can incorporate a high proportion of recycled resin, such as recycled high density polyethylene.

Description

FIELD OF THE INVENTION[0001]The invention pertains to building materials in sheet form for applications such as roofing and siding. More particularly, it pertains to sheet materials comprising thermoplastic resin and mineral filler and to methods of making such materials.BACKGROUND OF THE INVENTION[0002]Many types of natural and synthetic roofing materials are available in the market. Some of the more popular natural types include natural slate, shakes and shingles. Natural slate has long been a popular roofing material due to its attractive appearance and durability and also because it possesses other highly desirable properties such as being fireproof and waterproof. It is, however, very expensive and as a result is normally used for roofing in only the most expensive houses and in other structures where the increased cost can be justified. Slate is a brittle material and can be cracked or broken rather easily. Natural slate tiles are quite durable; however they require a substant...

Claims

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Application Information

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Patent Type & AuthorityApplications(United States)
IPC IPC(8): B29C43/24B29C48/07
CPCB29C43/24B29K2509/00B29K2023/0608B29C43/003B29K2105/26B29L2031/10B29L2031/108C08J5/18C08J2323/06C08L23/06C08L23/0815B29C48/07B29C48/914B29C48/906E04D5/06Y10T428/251Y10T428/25Y10T428/258Y10T428/259C08L2666/06
InventorWENSEL, GEOFFREY F.SUGGITT, ROBERT W.
OwnerG R GREEN BUILDING PRODS