US20160177483A1

US20160177483A1 - Composite reinforcement

Info

Publication number: US20160177483A1
Application number: US14/969,495
Authority: US
Inventors: Fabien Marc PESQUET; Lee Allen PEEKSTOK; Tao Yu
Original assignee: Saint Gobain Adfors Canada Ltd
Current assignee: Saint Gobain Adfors Canada Ltd
Priority date: 2014-12-19
Filing date: 2015-12-15
Publication date: 2016-06-23
Also published as: WO2016100297A1

Abstract

A composite reinforcement includes a first nonwoven mat. A laid scrim overlies the first nonwoven mat, the laid scrim including a first plurality of yarns substantially oriented in a first direction and a second plurality of yarns substantially oriented in a second direction different from the first direction. The second plurality of yarns includes at least one different material from the first plurality of yarns and each of the yarns in the second plurality of yarns includes a tension greater than a tension of each of the yarns in the first plurality of yarns. A second nonwoven mat overlies the laid scrim, and a binder laminates the first nonwoven mat, the laid scrim, and the second nonwoven mat together to form the composite reinforcement.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional App. No. 62/094,351, entitled “COMPOSITE REINFORCEMENT”, by Fabien Marc Pesquet et al., filed Dec. 19, 2014, which is assigned to the current assignee hereof and incorporated herein by reference in its entirety.

FIELD OF THE DISCLOSURE

The present disclosure relates to composite reinforcements for a variety of structural and industrial purposes, including reinforcements for building and roofing applications.

BACKGROUND

Roofing membranes include reinforcements meant to strengthen and extend the life of the membrane. However, commercially-available reinforcements for roofing membranes are prone to “mole running,” or installation defects caused by dimensional expansion along the length of the reinforcement, when the reinforcement is exposed to certain environmental conditions on the roof. This dimensional expansion can cause deformation of the reinforcement at one or more points where the roofing membrane is weakly adhered to the roof, leading to “mole runs” (e.g., ridges) in a direction perpendicular to the surface of the roof. Accordingly, a need continues to exist in the art for reinforcements that can meet new and sometimes demanding applications, including roofing reinforcements that are resistant to deformation in response to changing environmental conditions.

SUMMARY

In an embodiment, a composite reinforcement includes a first nonwoven mat, a laid scrim overlying the first nonwoven mat, where the laid scrim includes a first plurality of yarns substantially oriented in a first direction and a second plurality of yarns substantially oriented in a second direction different from the first direction, where the second plurality of yarns includes at least one different material from the first plurality of yarns and where each of the yarns in the second plurality of yarns includes a tension greater than a tension of each of the yarns in the first plurality of yarns, a second nonwoven mat overlying the laid scrim, and a binder laminating the first nonwoven mat, the laid scrim, and the second nonwoven mat together to form the composite reinforcement.
In another embodiment, a roofing membrane includes a composite reinforcement impregnated with an asphaltic composition, where the composite reinforcement includes a first nonwoven mat, a laid scrim overlying the first nonwoven mat, where the laid scrim includes a first plurality of yarns substantially oriented in a first direction and a second plurality of yarns substantially oriented in a second direction different from the first direction, where the second plurality of yarns includes at least one different material from the first plurality of yarns and where each of the yarns in the second plurality of yarns includes a tension greater than a tension of each of the yarns in the first plurality of yarns, a second nonwoven mat overlying the laid scrim, and a binder laminating the first nonwoven mat, the laid scrim, and the second nonwoven mat together to form the composite reinforcement.
In yet another embodiment, a composite reinforcement is configured for incorporation into a roofing membrane, where the composite reinforcement includes a polyester nonwoven mat, a laid scrim overlying the polyester nonwoven mat, where the laid scrim includes a plurality of fiberglass yarns oriented in a cross direction of the laid scrim and a plurality of polyester yarns and fiberglass yarns oriented in a main direction of the laid scrim, and where each of the polyester yarns and fiberglass yarns oriented in the main direction includes a tension greater than a tension of each of the fiberglass yarns oriented in the cross direction, a fiberglass nonwoven mat overlying the laid scrim, and a binder laminating the polyester nonwoven mat, the laid scrim, and the fiberglass nonwoven mat together to form the composite reinforcement.
In a further embodiment, a method of forming a composite reinforcement includes coating a laid scrim with a binder, where the laid scrim includes a first plurality of yarns substantially oriented in a first direction and a second plurality of yarns substantially oriented in a second direction different from the first direction, where the second plurality of yarns includes at least one different material from the first plurality of yarns and where each of the yarns in the second plurality of yarns includes a tension greater than a tension of each of the yarns in the first plurality of yarns, contacting the laid scrim with a first nonwoven mat and a second nonwoven mat, where the laid scrim overlies the first nonwoven mat and where the second nonwoven mat overlies the laid scrim; and curing the binder to form the composite reinforcement.
In still another embodiment, a method of preventing a distortion on a roofing surface includes applying a roofing membrane to the roofing surface, the roofing membrane including a composite reinforcement, where the composite reinforcement includes: a first nonwoven mat, a laid scrim overlying the first nonwoven mat, where the laid scrim includes a first plurality of yarns substantially oriented in a first direction and a second plurality of yarns substantially oriented in a second direction different from the first direction, where the second plurality of yarns includes at least one different material from the first plurality of yarns and where each of the yarns in the second plurality of yarns includes a tension greater than a tension of each of the yarns in the first plurality of yarns, a second nonwoven mat overlying the laid scrim, and a binder laminating the first nonwoven mat, the laid scrim, and the second nonwoven mat together to form the composite reinforcement, exposing the roofing membrane to an environmental condition, relieving the tension of at least some of the yarns in the second plurality of yarns in response to the environmental condition; and preventing the distortion on the roofing surface.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are illustrated by way of example and are not limited in the accompanying figures.

FIG. 1 depicts a composite reinforcement in accordance with an embodiment described herein.

FIGS. 2A-2B depict a laid scrim in accordance with an embodiment described herein.

FIG. 3 depicts a method of applying tension to, and relieving tension from, a yarn in accordance with an embodiment described herein.

FIG. 4 depicts a cross-sectional image of a composite reinforcement in accordance with an embodiment described herein.

FIG. 5 depicts a graph of composite reinforcement displacement in accordance with an embodiment described herein.

FIG. 6 depicts a graph of composite reinforcement air permeability in accordance with an embodiment described herein.

Skilled artisans appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the invention.

DETAILED DESCRIPTION

The following description in combination with the figures is provided to assist in understanding the teachings disclosed herein. The following discussion will focus on specific implementations and embodiments of the teachings. This focus is provided to assist in describing the teachings and should not be interpreted as a limitation on the scope or applicability of the teachings. However, other teachings can certainly be used in this application.
Before addressing details of the embodiments described below, some terms and phrases are defined or clarified. The term “filament” is intended to mean an elongated structure of any suitable length and material. The term “fiber” is intended to include a filament or filaments of any suitable fabric or tissue, material, or substance. A “fiber” can include both cut filaments and continuous filaments. The term “yarn” is intended to mean any ordered bundle of fibers, including a bundle of fibers that has been spun, plied, braided, or otherwise assembled in an ordered fashion. The term “mat” is intended to mean any suitable nonwoven structure containing filaments or fibers, including a randomized distribution of singular fibers. A “mat” may be formed by any suitable means, including by dry laid means, air laid means, meltblown means, or spunbond means. The term “scrim” is intended to mean any suitable assembly of yarns, including an ordered assembly of yarns, where the yarns may be oriented in one or more directions. The term “laid scrim” is intended to mean a nonwoven scrim. The term “composite” is intended to refer to a structure with two or more distinct layers.
As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a method, article, or apparatus that comprises a list of features is not necessarily limited only to those features but may include other features not expressly listed or inherent to such method, article, or apparatus. Further, unless expressly stated to the contrary, “or” refers to an inclusive-or and not to an exclusive-or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).
Also, the use of “a” or “an” is employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural, or vice versa, unless it is clear that it is meant otherwise. For example, when a single Embodiment is described herein, more than one Embodiment may be used in place of a single Embodiment. Similarly, where more than one Embodiment is described herein, a single Embodiment may be substituted for that more than one Embodiment.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The materials, methods, and examples are illustrative only and not intended to be limiting. To the extent not described herein, many details regarding specific materials and processing acts are conventional and may be found in reference books and other sources within the structural arts and corresponding manufacturing arts.
The present invention provides for a composite reinforcement. In an embodiment, the composite reinforcement includes a first nonwoven mat and a laid scrim overlying the first nonwoven mat, where the laid scrim includes a first plurality of yarns substantially oriented in a first direction and a second plurality of yarns substantially oriented in a second direction different from the first direction. The second plurality of yarns includes at least one different material from the first plurality of yarns and each of the yarns in the second plurality of yarns includes a tension greater than a tension of each of the yarns in the first plurality of yarns. The composite reinforcement further includes a second nonwoven mat overlying the laid scrim and a binder laminating the first nonwoven mat, the laid scrim, and the second nonwoven mat together to form the composite reinforcement.
The composite reinforcement as described herein is capable of counteracting the dimensional expansion experienced by commercially-available reinforcements. For example, the composite reinforcement and, in particular, the scrim as described herein, includes shrinkable material which can shrink or contract in response to a change in environmental conditions, thereby balancing a tendency of the reinforcement to expand in response to the environmental condition with a contraction or shrinkage that will enable the reinforcement to resist deformation. In a roofing application, the ability of a portion of the reinforcement to contract or shrink can lead to the prevention of undesirable ridges or “mole runs” in the reinforcement. The prevention of ridges, in turn, will desirably enable the roofing membrane to remain adhered to the roof surface as intended.
The composite reinforcement as described herein also is configured to be customizable. In an embodiment, the amount of contraction or shrinkage of the shrinkable material within the reinforcement can be tailored or customized to particular requirements by adjusting the process by which the reinforcement is made, including the process by which certain process variables (e.g., tension, heat) are applied to the shrinkable material within the reinforcement. The reinforcement also can be customized for particular applications, including applications that take into account the environmental conditions (e.g., temperatures) to which the reinforcement will be exposed in specific geographical areas.
The composite reinforcement as described herein also is configured to increase certain physical attributes when incorporated into other structures. For example, when used to create a roofing membrane, the composite reinforcement described herein is intended to increase (a) the peel strength of the roofing membrane from the roof surface; and (b) the asphaltic permeation of the composite reinforcement. With respect to peel strength, the peel strength between the layers of the composite reinforcement can be tailored depending on whether an unsaturated coating technique or a saturated coating technique, each as described herein, is used. In an embodiment, the peel strength between the layers can be increased using an unsaturated coating technique. Also with respect to peel strength, the manner and location(s) in which a binder is distributed within one or more layers of the composite reinforcement can maximize the air permeability of that layer, which in turn leads to an increased ability to permeate the reinforcement with asphalt. As a result, the distribution of a binder within one or more layers may impact the delamination of the asphalt from the layer(s) and/or may impact the delamination of one or more layers from other layers within the reinforcement (e.g., a mat layer from a scrim layer).
The composite reinforcement includes a first nonwoven mat. The first nonwoven mat can be made of any suitable organic or inorganic material, including any material suitable for use in a roofing membrane. In an embodiment, the first nonwoven mat is made of at least one suitable thermoset or thermoplastic polymeric material, or a blend of suitable polymeric materials. For example, the first nonwoven mat can include a polyester, such as polyethylene terephthalate (PET). In a particular embodiment, the first nonwoven mat can consist essentially of a polyester. In another embodiment, the first nonwoven mat can incorporate multicompound fibers, or fibers that have been extruded with different materials in the core and shell/coating structures, respectively.
The first nonwoven mat can include any suitable structure or configuration. In an embodiment, the first nonwoven mat can include a randomized distribution of singular fibers. The fiber weight can include suitable fiber weights between 0.5 denier and 5 denier, such as approximately 1.5 denier. In a particular embodiment, the first nonwoven mat can include a multifilament carded web. The first nonwoven mat also can include any suitable dimensions, including those standard industrial dimensions established by the mat supplier, who can supply the mat in the form of a rolled good. For example, the first nonwoven mat can include a thickness of between about 1 mil and about 10 mils, such as 5 mils or 7 mils. The first nonwoven mat also can include any suitable length. In an embodiment, the length of the first nonwoven mat can correspond to a length of a standardized roofing membrane, such as a length of approximately 72 feet. The first nonwoven mat further can include any suitable width. In an embodiment, the width of the first nonwoven mat can correspond to a width of a standardized roofing membrane, such as a width of approximately 36 inches. The first nonwoven mat can include any other suitable dimensions or physical properties, including a basis weight of between approximately 0.5 oz/yd²and approximately 2 oz/yd². In an embodiment, the first nonwoven mat can include a tensile strength of between approximately 75 lbs/inch and approximately 1200 lbs/inch. As discussed herein, the first nonwoven mat, as one layer of the composite reinforcement, can include a peel strength. In an embodiment, the peel strength of the first nonwoven mat from the other layers of a composite reinforcement formed using an unsaturated coating technique, can include a peel strength between approximately 1 lb/inch of width of the mat and approximately 6 lbs/inch of width of the mat.
The composite reinforcement also includes a second nonwoven mat, which can be the same as the first nonwoven mat or can differ from the first nonwoven mat in dimension(s), type of material, or any other suitable respect. The second nonwoven mat can be made of any suitable organic or inorganic material, including any material suitable for use in a roofing membrane. In an embodiment, the second nonwoven mat is made of at least one suitable fiberglass material, including any suitable alkali-resistant glass, C-glass, or E-glass, a basalt material, a carbon material, a metal material, a ceramic material, or a combination thereof. In a particular embodiment, the second nonwoven mat can consist essentially of fiberglass fibers.
Like the first nonwoven mat, the second nonwoven mat can include any suitable structure or configuration. In an embodiment, the second nonwoven mat can include a distribution of randomly oriented fibers. The second nonwoven mat also can include any suitable dimensions, including dimensions that are the same as or different from those of the first nonwoven mat. For example, the second nonwoven mat can include a thickness of between about 10 mils and about 20 mils, such as between about 15 mils and 18 mils. The second nonwoven mat also can include any suitable length. In an embodiment, the length of the second nonwoven mat can correspond to a length of a standardized roofing membrane, such as a length of approximately 72 feet. The second nonwoven mat further can include any suitable width. In an embodiment, the width of the second nonwoven mat can correspond to a width of a standardized roofing membrane, such as a width of approximately 36 inches. The second nonwoven mat can include any other suitable dimensions, including a basis weight of between approximately 0.5 lbs/100 ft²and approximately 2.0 lbs/100 ft², such as between approximately 0.7 lbs/100 ft²and approximately 0.9 lbs/100 ft².
Within the composite reinforcement, the first and second nonwoven mats may or may not be in contact with each other along one or more suitable surfaces. In an embodiment, the first and second nonwoven mats are not in contact with each other along any minor or major surface of either mat, being separated by at least one intervening layer within the composite reinforcement. Furthermore, it will be understood that while the composite reinforcement has been described in terms of having two nonwoven mats, the composite reinforcement can include any suitable number of nonwoven mats arranged relative to one another and to the composite reinforcement in any suitable orientation, each of which may be the same as or different from the mats described herein. In addition, the orientation of the first and second nonwoven mats relative to one other and relative to the composite reinforcement can include any suitable orientation. In an embodiment, the first nonwoven mat can be configured such that it is oriented or positioned “below” or “underneath” the second nonwoven mat within the composite reinforcement while the second nonwoven mat can be configured such that it is oriented or positioned “above” the first nonwoven mat.
The composite reinforcement further includes a scrim. In a particular embodiment, the scrim includes a laid scrim. The scrim is configured to be oriented or positioned in any suitable location relative to the composite reinforcement and each of the first and second nonwoven mats. For example, the scrim can be positioned or “sandwiched” between the first and second nonwoven mats such that the scrim is in partial or full contact with at least one of the first and second nonwoven mats (e.g., at least a portion of a surface of the scrim contacts at least a portion of a surface of at least one of the first and second nonwoven mats). The scrim includes any suitable dimensions, including dimensions that are the same as or different from those of any of the other layers within the composite reinforcement. For example, the scrim can include a thickness of between about 12 mil and about 70 mil. The scrim also can include any suitable length, including a length of a standardized roofing membrane and/or a length of either of the first and second nonwoven mats, such as a length of approximately 72 feet. The scrim further can include any suitable width, including a width of a standardized roofing membrane and/or a width of either of the first and second nonwoven mats, such as a width of approximately 36 inches.
The scrim includes yarns. In an embodiment, the scrim includes a first plurality of yarns and a second plurality of yarns. Each plurality of yarns includes a random or ordered assembly of one or more yarns. The second plurality of yarns includes yarns that can be the same as or different from the yarns in the first plurality of yarns. In an embodiment, at least some of the yarns in the second plurality of yarns are different from the first plurality of yarns in any suitable manner. For example, the second plurality of yarns can include yarns of a different quantity, spacing, type, configuration, dimension, arrangement, material (e.g., composition or substance), or combination thereof, from the first plurality of yarns. In a particular embodiment, the second plurality of yarns includes yarns with at least one different material from the yarns in the first plurality of yarns. Although the scrim is described herein in terms of a first plurality of yarns and a second plurality of yarns, it will be understood that the scrim can include any suitable number or pluralities of yarns as desired, including a third plurality of yarns that may be the same as, or different from, either or both of the first and second pluralities of yarns.
The yarns of the scrim can include any suitable organic or inorganic material, including any material suitable for use in a roofing membrane. In particular, the yarns of the scrim can include shrinkable material which can shrink or contract. In an embodiment, the first plurality of yarns includes fiberglass yarns, namely yarns made at least partly of or entirely of a suitable fiberglass material, including any suitable alkali-resistant glass, C-glass, or E-glass. The fiberglass yarns can include a sizing. In a particular embodiment, the first plurality of yarns consists essentially of fiberglass yarns. The second plurality of yarns can also include fiberglass yarns, either yarns made at least partly of or entirely of the same fiberglass material as the yarns of the first plurality, or yarns made at least partly of or entirely of a different fiberglass material than the yarns of the first plurality. These fiberglass yarns can include any suitable yarn weight, such as a yarn weight between approximately 330 dtex and approximately 2,750 dtex.
The second plurality of yarns further can include yarns of at least one different material from the yarns in the first plurality of yarns. For example, the second plurality of yarns also can include yarns made at least partly of or entirely of any suitable organic material, such as any suitable thermoset or thermoplastic polymeric material. These polymeric yarns can include any suitable yarn weight, such as a yarn weight between approximately 200 denier and approximately 1,500 denier. In an embodiment, the polymeric material includes the shrinkable material such as polyester, including lower shrinkage polyester yarns and higher shrinkage polyester yarns, polyamide (nylon), rayon, or a combination thereof. In a particular embodiment, the polymeric material can include polyethylene terephthalate (PET). In a particular embodiment, the second plurality of yarns can consist essentially of polyester yarns. In another particular embodiment, the second plurality of yarns can consist essentially of lower shrinkage polyester yarns. In still another particular embodiment, the second plurality of yarns can consist essentially of higher shrinkage polyester yarns. A lower shrinkage yarn can include a yarn that is configured to shrink less than 3% along a given dimension, while a higher shrinkage yarn can include a yarn that is configured to shrink greater than 3% along a given dimension, according to ASTM D-2259. In addition, the second plurality of yarns can include any suitable ratio of yarns of different materials (e.g., blends of different yarns). For example, the second plurality of yarns can include at least 1% polyester yarns, such as at least 5%, at least 10%, at least 25%, at least 50%, at least 60%, at least 70%, at least 75%, at least 80%, or even at least 85% polyester yarns. The second plurality of yarns also can include less than 99% fiberglass yarns, such as less than 95%, less than 90%, less than 75%, less than 50%, less than 40%, less than 30%, less than 25%, less than 20%, or even less than 15% fiberglass yarns.
The yarns of the scrim can be oriented or positioned in any suitable direction. For example, the first plurality of yarns can be substantially oriented in a first direction (e.g., a first direction of the scrim) and the second plurality of yarns can be substantially oriented in a second direction (e.g., a second direction of the scrim). In an embodiment, the second direction is different from the first direction. In another embodiment, the second direction is substantially the same as the first direction. By “substantially oriented,” it is meant that at least 50%, such as at least 60%, at least 70%, at least 75%, at least 80%, at least 90%, or even at least 95% of the yarns within a given plurality of yarns is oriented in a given direction. It will be understood that a suitable direction can be described in terms of a direction, axis, or dimension of the scrim itself. In an embodiment, the first direction can include, correspond to, or be parallel to a cross, or weft, direction of the scrim. The cross direction of the scrim can include a direction that is parallel to a width of the scrim. The second direction can include, correspond to, or be parallel to a main, machine, or warp direction of the scrim. The main direction of the scrim can include a direction that is parallel to a length of the scrim. The first and second directions also can be oriented at any suitable angle with respect to each other. In a particular embodiment, the first direction can be substantially perpendicular to or substantially orthogonal to the second direction. For example, the scrim can include a 0/90 scrim where the first direction is substantially perpendicular to the second direction and the first plurality of yarns are substantially oriented perpendicular to the second plurality of yarns.
Within a given plurality of yarns, the yarns can be oriented relative to one another in any suitable manner. For example, within a plurality of yarns, the yarns can be substantially oriented parallel to one another. The yarns also can be positioned at any suitable distance from one another. In an embodiment, the yarns within a plurality of yarns can be at least partially in contact with one another. In another embodiment, the yarns can be spaced apart from one another, expressed in units of yarns per inch. For example, in a given direction, the yarn spacing can include at least about 12 yarns per inch, such as at least about 9 yarns per inch, at least about 8 yarns per inch, at least about 7.5 yarns per inch, at least about 6 yarns per inch, at least about 5.5 yarns per inch, at least about 5 yarns per inch, at least about 4 yarns per inch, or even at least about 1 yarn per inch. In a particular embodiment, the first plurality of yarns can include yarns spaced between about 1 yarn per inch and about 12 yarns per inch, such as at least 5.5 yarns per inch in the first direction. The second plurality of yarns can include yarns spaced between about 1 yarn per inch and about 12 yarns per inch, such as at least 7.5 yarns per inch in the second direction. It will be further understood that, because a given plurality of yarns can include yarns of more than one material, the spacing of the yarns can also incorporate any suitable pattern of yarns of different materials. For example, within the second plurality of yarns, the yarns can be oriented such that one or more yarns of a first material (e.g., polyester) are interspersed or alternated with one or more yarns of a second material (e.g., fiberglass). In an embodiment, one or more polyester yarns can be interspersed between one or more fiberglass yarns. In a particular embodiment, the second plurality of yarns can be spaced at approximately 7.5 yarns per inch in the second direction, which spacing can include a pattern of approximately five fiberglass yarns and 2.5 polyester yarns per inch.
Between separate pluralities of yarns, the yarns can be positioned relative to one another in any suitable manner. If the scrim is woven, the yarns of the first plurality of yarns can be interwoven with the yarns of the second plurality of yarns. In an embodiment, the scrim includes a laid scrim and the yarns of the first plurality of yarns can be laid on top of, below, or in between at least some of the yarns of the second plurality of yarns. In a particular embodiment, the yarns of the first plurality of yarns are laid between the yarns of the second plurality of yarns such that some of the yarns of the second plurality are positioned above the yarns of the first plurality, while other yarns of the second plurality are positioned below the yarns of the first plurality. The yarns of the first plurality of yarns can even be laid between yarns of different material of the second plurality of yarns. For example, the first plurality of yarns can be laid on top of yarns of a first material (e.g., polyester yarns) and laid below yarns of a second material (e.g., fiberglass yarns) from the second plurality of yarns.
Within the scrim, at least some of the yarns can include a tension. By “tension,” it is meant that a yarn can be subjected to, placed under, or have applied to it, an external force which results in the yarn having a measurable tension on it. It will be understood, however, that where one or more yarns are described as having a tension, that tension also can include a zero value or no tension.
The external force can be applied to the yarn at any suitable time or by any suitable means during the manufacture of the yarn and/or the scrim, and the yarn can include a tension or remain tensioned in the finished scrim. The tension can be measured and expressed in any suitable units of force per unit of linear density of the yarn. In an embodiment, the units of tension include Newtons per tex (e.g., N/tex or cN/tex). In certain instances, the tension also can be expressed as a function of the amount of binder present on or picked up by a given yarn, which binder is described in more detail herein.
Each of the yarns within the scrim can include any suitable tension. In an embodiment, each of the yarns in the scrim can include a tension between about 0 cN/tex and about 18 cN/tex. For example, at least one of the yarns in the first plurality of yarns can include a tension of about 0 cN/tex. In a particular embodiment, each of the yarns in the first plurality of yarns includes a tension of about 0 cN/tex. Yarns within a given plurality of yarns can include the same tension as, or a different (e.g., greater or lesser) tension from, yarns within another plurality of yarns. For example, at least some of the yarns of the second plurality of yarns can include a tension greater than or lesser than that of the yarns of the first plurality of yarns. In a particular embodiment, each of the yarns in the second plurality of yarns includes a tension greater than a tension of each of the yarns in the first plurality of yarns.
Different yarns within a given plurality of yarns also can include different tensions. For example, different yarns within the second plurality of yarns can include different tensions. In an embodiment, each of the yarns within the second plurality of yarns can include a tension between about 1.0 cN/tex and about 18 cN/tex. Furthermore, different yarns made of different materials within a given plurality of yarns can include different tensions. In a particular embodiment, one or more yarns of a first material (e.g., polyester yarns) in the second plurality of yarns can include a different tension from, such as a greater tension than, one or more yarns of a second material (e.g., fiberglass yarns) in the second plurality of yarns. For example, each polyester yarn can include a tension of between about 7.2 cN/tex and about 10.8 cN/tex. Each fiberglass yarn can include a tension of between about 2.2 cN/tex and about 6.6 cN/tex.
The composite reinforcement further includes a binder or binder composition. The binder includes any suitable organic resin. The organic resin can include one or more suitable polymers, one or more suitable copolymers, a suitable blend, or combination thereof. In an embodiment, the organic resin includes materials designed to withstand hot asphalt coating during the roofing membrane-making process. For example, the organic resin is a thermosetting resin. The binder also includes any suitable composition sufficient to laminate together the first nonwoven mat, the scrim, and the second nonwoven mat to form the composite reinforcement. In one embodiment, the binder includes an acrylic or acrylate. In another embodiment, the binder includes a polyvinyl alcohol. In yet another embodiment, the binder includes a styrene butadiene rubber composition. The styrene butadiene rubber composition can be cross-linked styrene butadiene rubber, including between about 30% to about 80% styrene, such as about 45% to about 75% styrene, such as about 50% to about 70% styrene, such as about 55% styrene. The binder also can include any suitable additive or filler to provide advantageous properties to the binder, the composite reinforcement, and/or any of its layers.
The binder can be present within each layer of the composite reinforcement, but may or may not be present throughout the entirety of each layer. In an embodiment, the binder can penetrate through the entirety of (e.g., saturate) the scrim and one or more of the first and second nonwoven mats. For example, the binder can penetrate through the entirety of the scrim and the second nonwoven mat (e.g., the fiberglass mat). In another embodiment, the binder can penetrate through the entirety of (e.g., saturate) the scrim, but the binder may only penetrate a portion of either of the first or second nonwoven mats without saturating either mat or penetrating through the entirety of either mat.
The binder also can be present at any suitable concentration within the composite reinforcement, and different layers of the reinforcement can include different concentrations of the binder. For example, the scrim can include a greater concentration of binder than either of the first or second nonwoven mats. The binder can further be present at varying concentrations within a given layer. As noted herein, the binder can be present at a given concentration in a portion of either of the first or second nonwoven mats, but may not be present at any concentration in another portion of the same mat. In another embodiment, different yarns within the scrim can include different concentrations of the binder. For example, where the second plurality of yarns includes yarns of different materials, such as both polyester yarns and fiberglass yarns, each of the polyester yarns can include a greater concentration of binder on it than each of the fiberglass yarns. Where the first plurality of yarns also includes fiberglass yarns, each of the fiberglass yarns of the first plurality of yarns can include a greater concentration of binder on it than each of the fiberglass yarns within the second plurality of yarns.
The concentration of binder on or within a given layer of the composite reinforcement can be expressed in any suitable manner, including as a percentage of dry coating per unit (DPU). The DPU percentage reflects the ratio of the weight of dried or cured binder present in a given layer to the weight of the layer itself. For example, a 100% DPU indicates that the weight of the dried or cured binder present in a layer (e.g., the scrim) is equal to the weight of the layer itself. In an embodiment, the concentration of binder on the scrim can include a DPU percentage between about 50% and about 150% DPU.
The composite reinforcement can be formed in any suitable manner. In an embodiment, the first nonwoven mat, the second nonwoven mat, and the scrim are formed first. Each of the mats can be produced by any of the means disclosed herein. The scrim can be formed by any suitable woven or nonwoven means. In a particular embodiment, the scrim includes a laid scrim, in which the first and second pluralities of yarns are laid in a desired nonwoven configuration or arrangement to form the scrim. Prior to formation of the scrim, or concurrently with the formation of the scrim, one or more external forces can be applied to at least some of the yarns in the scrim such that the finished scrim includes at least some yarns with a tension. In an embodiment, the external force is applied to at least some of the yarns in the main direction simultaneously with the formation of the scrim.
Any method of providing the binder to any layer of the composite reinforcement is envisioned. For instance, the scrim then can be coated with the binder in any suitable manner, including by known dip coating, spray coating, and extrusion coating techniques. In an embodiment, the scrim can be coated with the binder while the binder is in a liquid state. Excess amounts of the binder can be removed from the scrim using any known technique. In an “unsaturated” method or technique, the scrim can be coated as described to saturate or soak the scrim in the liquid binder, but neither the first nonwoven mat nor the second nonwoven mat may be similarly coated (e.g., neither mat is coated concurrently with the scrim). After the scrim has been coated with the liquid binder, the scrim can be contacted with or introduced to at least one of the first nonwoven mat and the second nonwoven mat. For example, the scrim is brought into contact with each of the first nonwoven mat and the second nonwoven mat. Bringing these three layers into contact after the scrim has been coated with the liquid binder permits at least some of the liquid binder to migrate from the scrim and penetrate at least a portion of each of the first and second nonwoven mats without saturating or fully penetrating either of the mats with the liquid binder. For example, when an unsaturated coating technique is used to form the composite reinforcement, the binder can penetrate less than approximately 50% of a thickness of the first nonwoven mat and less than approximately 33-35% of a thickness of the second nonwoven mat. In a “saturated” method or technique, both the scrim and at least one of the first and second nonwoven mats can be coated together with the binder while the binder is in a liquid state. For example, both the scrim and the second nonwoven mat (e.g., the fiberglass mat) can be coated with the liquid binder, which permits the liquid binder to saturate or fully penetrate both the scrim and the second nonwoven mat. The third layer (e.g., the first nonwoven mat) is then brought into contact with the other layers, such that a portion of the liquid binder migrates from the scrim to penetrate at least a portion of the first nonwoven mat without saturating the first nonwoven mat. When a saturated coating technique is used to form the composite reinforcement, the binder can penetrate less than 20% of a thickness of the first nonwoven mat, such that less binder penetrates a thickness of the first nonwoven mat in the saturated technique than in the unsaturated technique. Without wishing to bound by theory, the unsaturated technique produces a composite reinforcement with less binder present in both of the mat layers than the amount of binder present in both mat layers using the saturated technique. Less binder saturation of the mat layers can facilitate a greater saturation or penetration of those same layers by an asphaltic composition when the composite is used to make a roofing membrane. Greater saturation or penetration of the mat layers by the asphaltic composition can lead to greater interlaminar strength within the reinforcement (e.g., less delamination between the layers of the composite reinforcement) and increased peel strength of the resulting roofing membrane.
After the layers are brought into contact with one another, the binder can be cured in any suitable manner to form the composite reinforcement. In an embodiment, the layers can be transported to an oven operating at a temperature sufficient to cure the binder. For example, the layers can reside in the oven for a suitable period of time, such as at least thirty seconds, at least one minute, or at least 1.5 minutes. The oven can include a temperature, or include internal devices (e.g., steam-heated drying cans) at a temperature such as at least 250 degrees Fahrenheit, or at least 300 degrees Fahrenheit. One effect of curing the binder on the layers of the composite reinforcement is that, where applied, at least a portion of the tension on the yarns in the scrim is also “heat set,” “memorized,” or “fixed,” such that when the composite reinforcement is removed from the oven and allowed to cool, the tension of the yarns in the scrim is retained (e.g., is not relieved). More specifically, those yarns in the scrim that have a tension, by virtue of having an external force applied when they enter the oven, also can have an internal stress due to the internal alignment of the molecular chains or chain segments within the yarns. For example, the introduction of an external force (e.g., a weight) to a yarn in the scrim, can provide a measureable tension to a yarn, can also lock in place the molecular structure of that yarn such that the internal alignment of the molecular chains or chain segments within the yarn increases. The increased internal alignment of the molecular chains or chain segments within the yarn creates and/or increases an internal stress between the molecular chains. Both the tension of the yarn, caused by the application of an external force to the yarn, and the internal stress of the yarn, caused by the increased internal alignment of the molecular chains, can result in a stretched or elongated yarn. When such a yarn is exposed to the heat source, some of the internal stress between the molecular chains or chain segments may be relaxed, but at least a portion of the yarn elongation (resulting from the chain alignment) and the tension of the yarn (from the application of the external force) are retained. Such elongation is memorized or fixed as the yarn cools, and the yarn can retain the tensile force in the finished composite reinforcement until exposed to a future heat source, such as, for example, the ambient heat from a roof. Once cooled, the composite reinforcement can be further processed, packaged, and transported for use as a structural reinforcement. In an embodiment, the composite reinforcement can be partially or fully impregnated with an asphaltic composition (e.g., an asphaltic/rubber composition) to form a roofing membrane for reinforcing a roof. It will be understood that the composite reinforcements described herein can be used to form a roofing membrane that meets accepted commercial standards for roofing membranes, such as the industrial specifications set forth in ASTM D-6162.
As described herein, traditional commercially-available reinforcements, such as those installed in roofing membranes, are prone to “mole running” or dimensional expansion along the length of the reinforcement when the roof, and the reinforcement, are exposed to certain environmental conditions (e.g., diurnal heating, sunshine, and/or elevated ambient temperatures). For example, a roof can include a surface temperature of about 40 degrees Fahrenheit in the morning, but that same roof can achieve surface temperatures of at least 150 degrees Fahrenheit, such as at least 175 degrees or even at least 180 degrees Fahrenheit, in the same day. When the roof heats to such a degree, the dimensional expansion experienced by the reinforcement can cause deformation or distortion of the reinforcement at one or more points where the roofing membrane is weakly adhered to the roof, leading to undesirable ridges (e.g., “mole runs”) in a direction perpendicular to the surface of the roof.
The composite reinforcement described herein, particularly the shrinkable material within the composite reinforcement, can contract in response to a change in environmental conditions, thereby preventing or counteracting any initial dimensional expansion that would lead to such distortion in the roofing membrane. In an embodiment, the composite reinforcement described herein can begin to exhibit such desirable contraction when a roofing membrane in which the reinforcement is incorporated (and/or the itself) reaches a surface temperature of at least 35 degrees Celsius. More specifically, the tensioned yarns of the scrim within the composite reinforcement include the internal stress that is configured to be relieved. The tensioned yarns have built in thermal stress because of the forced alignment of the molecular chain or chain segments. When the tensioned yarns are exposed to a heat source (e.g., from diurnal warming of the reinforcement and/or the roofing membrane on the surface of a roof), the internal stress on those yarns is released as the aligned molecular chains within the yarns seek a more disordered arrangement. This release of the internal stress causes the yarns to shrink, eliminating the elongation of the yarns and the tension on the yarns. Such shrinkage is sufficient to overcome a tendency of the yarns within the scrim (and the composite reinforcement) to otherwise expand undesirably in response to the heat source. In an embodiment, the tension on certain of the yarns (e.g., the yarns made of the shrinkable material) in the scrim is configured to be relieved. In another embodiment, the tension of all of the yarns in the scrim is configured to be relieved. In a particular embodiment, the tension of at least some of the yarns in the second plurality of yarns in the scrim is configured to be relieved.
The tension can be relieved by any suitable means. For example, the tension is configured to be relieved by shrinkage of at least some of the yarns, including the yarns made of the shrinkable material. The shrinkage can occur in a variety of suitable directions or dimensions, including in a direction parallel to a dimension of the yarn (e.g., a width or length of the yarn) and/or a direction or dimension of the scrim. In a particular embodiment, shrinkage can occur along a length of a yarn, which length can be parallel to the second direction described herein, parallel to a main, machine, or warp direction of the scrim, and/or parallel to a length of the scrim.
The shrinkage of the yarns also can include any suitable dimensional change in the yarns, including a shortening of the yarns and, in some instances, an increase in diameter of the yarns. In a particular embodiment, the shortening includes a shortening of a yarn along its length. This shortening can be measured using any suitable method, including those methods set forth in commercially-available industry standards such as ASTM D-2259. Each of the yarns whose tension is relieved can include any suitable amount of shortening. In an embodiment, relieving the tension on a given yarn can shorten that yarn by between about 0.2% and about 15%, as compared to the length of the yarn before its tension was relieved (e.g., the length of the tensioned yarn in the finished composite reinforcement).
Turning to FIG. 1, a composite reinforcement is depicted in accordance with an embodiment described herein. It will be understood that, while the composite reinforcement 100 is described in terms of three layers 110, 120, and 130, the composite reinforcement 100 can include any suitable number or combination of different layers. The composite reinforcement includes a first nonwoven mat 110, a second nonwoven mat 120, and a scrim 130. In an embodiment, the first nonwoven mat 110 includes polyester fibers or is a polyester mat. In a particular embodiment, the first nonwoven mat 110 consists essentially of polyester fibers. The second nonwoven mat 120 can include fiberglass fibers or be a fiberglass mat. In a particular embodiment, the second nonwoven mat 120 consists essentially of fiberglass fibers. A scrim 130 can be sandwiched between, and separate, the first nonwoven mat 110 and the second nonwoven mat 120. The scrim 130 can include any suitable woven or nonwoven scrim and, in an embodiment, the scrim 130 includes a laid scrim 130.
Turning to FIG. 2A, the laid scrim 130 is depicted in accordance with an embodiment described herein. It will be understood that, while the laid scrim 130 is described and depicted in terms of two pluralities of yarns 140 and 150, the laid scrim 130 can include any suitable number of pluralities of yarns arranged in any suitable configuration. A first plurality of yarns 140 can include any suitable number of yarns 141. Each yarn 141 can include any suitable material and be substantially oriented in any suitable direction. In an embodiment, the first plurality of yarns 140 includes fiberglass yarns 141. In another embodiment, each yarn 141 includes fiberglass and, in a particular embodiment, each yarn 141 consists essentially of fiberglass. At least some of the yarns 141, or each of the yarns 141, can be substantially oriented in a first direction C. In an embodiment, the first direction C can be parallel to a cross or weft direction of the laid scrim 130. The yarns 141 can further include any suitable spacing 145, expressed in terms of yarns per inch. In an embodiment, the yarns 141 can include a spacing of between about 1 yarn per inch and about 12 yarns per inch, such as about 5.5 yarns per inch.
A second plurality of yarns 150 can include any suitable number of yarns 151 and 153. Each yarn 151 and 153 can include any suitable material and be substantially oriented in any suitable direction. In an embodiment, the second plurality of yarns 150 includes yarns of a first material and yarns of a second material. For example, the second plurality of yarns 150 includes fiberglass yarns 151 and polyester yarns 153 (e.g., lower shrinkage polyester yarns 153 and/or higher shrinkage polyester yarns 153). In a particular embodiment, each yarn 151 consists essentially of fiberglass and each yarn 153 consists essentially of polyester. At least some of the yarns 151 and 153, or each of the yarns 151 and 153, can be substantially oriented in a second direction M. In an embodiment, the second direction M can be parallel to a main, machine, or warp direction of the laid scrim 130. In a particular embodiment, the second direction M can be substantially perpendicular to the first direction C, and the laid scrim 130 can include a 0/90 scrim. The yarns 151 and 153 can further include any suitable spacing 155, expressed in terms of yarns per inch. In an embodiment, the yarns 151 and 153 can include a spacing of between about 1 yarn per inch and about 12 yarns per inch, such as about 7.5 yarns per inch.
Turning to FIG. 2B, a cross-section of the laid scrim 130 of FIG. 2A, taken along the first direction C, is depicted in accordance with an embodiment described herein. The yarns 141, 151, and 153 of the first and second pluralities of yarns 140 and 150 can be laid relative to one another in any suitable configuration or pattern. In an embodiment, the yarns 151 and 153 of the second plurality 150 can be laid in a repetitive pattern. For example, one yarn 153 can be laid in between four yarns 151 (e.g., one yarn 153 is laid after two yarns 151 are laid). Moreover, the yarns 141 can be laid between the yarns 151 and 153. For example, as the laid scrim 130 is formed, the yarns 141 are laid on top of the yarns 153, and the yarns 151 are laid on top of the yarns 141.
Turning to FIG. 3, a method of applying tension to, and relieving tension from, a yarn is depicted in accordance with an embodiment described herein. A yarn, such as a yarn made of shrinkable material (e.g., a polyester yarn 153 from FIGS. 2A-B) can be provided for incorporation into a scrim, such as the laid scrim 130, with an original length L. The yarn 153 may not include a tension, or any internal stress, at this stage. At step 310, a force 313 (e.g., an external weight) is applied to the yarn 153, which elongates the yarn 153 to a new length P. In an embodiment, the force 313 can include a weight between about 800 grams and about 1200 grams. The application of the force 313 to the yarn 153, and the elongation of the yarn 153 (which may, in part, result from the creation of, or an increase in, an internal stress of the yarn 153), results in the yarn 153 having a tension that can be expressed in any suitable units, such as units of force per linear density of the yarn (e.g., N/tex or cN/tex). At step 320, heat can be applied to the yarn 153, while the force 313 is still being applied to the yarn 153, to “heat-set” or “memorize” the elongation of the yarn 153. In an embodiment, this heat can include the oven used to cure the binder on the layers of the composite reinforcement 100. As a result, the yarn 153 retains a tension and an elongated length (due, in part, to an internal stress on the yarn 153) after the heat is removed from the yarn 153. Each of the steps 310 and 320 can be adjusted (e.g., by adjusting the amount of the force 313 and/or the amount of heat applied to the yarn 153) to tailor the tension included in the yarn 153, as well as to tailor the amount of shrinkage (i.e., due to release of an internal stress on the yarn 153) that the yarn 153 can undergo at a later time (e.g., during step 340). At step 330, the force 313 can be removed from the yarn 153. When the force 313 is removed, some of the elongation in the yarn 153 can be lost. One way in which the elongation in the yarn 153 is lost is by partial longitudinal shrinkage of the yarn 153 from the elongated length P to a new length N. Despite this partial shrinkage, however, tension remains in the yarn 153, as also evidenced by the elongation of the yarn 153 from its original length L to the new length N. It is this tension and elongated length N which are present in the yarn 153 when it is incorporated into the laid scrim 130.
Step 340 can occur at any suitable future time, including at a time when the laid scrim 130 (and the yarn 153) have been incorporated into the composite reinforcement 100 that, in turn, has been incorporated into a roofing membrane applied to a roof. During step 340, heat can be applied again to the yarn 153. For example, heat in the form of sunshine or diurnal warming can be applied to the yarn 153. In response to the application of the heat, the yarn may experience an initial dimensional expansion, after which the tension on the yarn 153 can be relieved (due to, for example, release of the internal stress in the yarn 153 which causes the yarn 153 to lose elongation), such that the yarn 153 can experience a final shrinkage 350 to a shortened length S. In an embodiment, relieving the tension on the yarn 153 can shorten that yarn by between about 0.2% and about 15% between lengths N and S. The final shrinkage 350 of the yarn 153 can include an initial shrinkage 360 from the original length L to the shortened length S, which can be the result of the yarn 153 shrinking irrespective of any heat-setting step performed at step 320. The final shrinkage 350 also can include an extended shrinkage 370, from the length N to the original length L, which extended shrinkage 370 is the result of relieving the tension that was applied to the yarn 153 (e.g., via the force 313) and heat-set within the yarn 153 at steps 310 and 320. As a result, not only can the amount of tension applied to the yarn 153 be tailored at steps 310 and 320, but the amount of future shrinkage experienced by the yarn 153 as the tension on the yarn 153 is relieved also can be predicted and tailored. The ability to predict and tailor the future shrinkage of the yarn 153 also enables the laid scrim 130, and the composite reinforcement 100, to be specifically designed to counteract dimensional expansion, and deformation, in particular geographical settings or environmental conditions.
FIG. 4 depicts a cross-sectional image of the composite reinforcement 100 in accordance with an embodiment described herein. The cross-sectional image of the composite reinforcement 100 was obtained using computer tomography (CT) scanning and was taken along a line parallel to the first direction C. A yarn 141 from the first plurality of yarns 140 (e.g., a fiberglass weft yarn of the laid scrim 130) is depicted by the white line or stripe shown across the center of FIG. 4. A cross-sectional image of a yarn 151 from the second plurality of yarns 150 (e.g., a fiberglass warp yarn of the laid scrim 130) is depicted by the white structure in the center of the image. Because inorganic materials appear more brightly, or with more contrast, than organic materials in an image made by CT scanning, the first nonwoven mat 110 (e.g., a polyester mat) is not discernible in FIG. 4, but is positioned below the yarn 141. The second nonwoven mat 120 (e.g., a fiberglass mat) is depicted above the yarns 141 and 151, with the white flecks or spots indicating the presence of inorganic material (e.g., fiberglass) in the mat. A cross-sectional image of a yarn 153 (e.g., a polyester warp yarn of the laid scrim 130) also is not discernible in FIG. 4, but the yarn is positioned to the left of the yarn 151 and below the yarn 141, such that the yarn 141 is sandwiched between the yarns 151 and 153 in the laid scrim 130. An organic binder (e.g., the binder 415) is present on and around the yarns 141, 151, and 153. Because an unsaturated technique was employed to coat the laid scrim 130, the binder 415 can saturate the laid scrim 130, but may penetrate only a portion of each of the first nonwoven mat 110 and the second nonwoven mat 120.

EMBODIMENTS

Embodiment 1

A composite reinforcement including a first nonwoven mat, a laid scrim overlying the first nonwoven mat, wherein the laid scrim includes a first plurality of yarns substantially oriented in a first direction and a second plurality of yarns substantially oriented in a second direction different from the first direction, wherein the second plurality of yarns includes at least one different material from the first plurality of yarns and wherein each of the yarns in the second plurality of yarns includes a tension greater than a tension of each of the yarns in the first plurality of yarns, a second nonwoven mat overlying the laid scrim, and a binder laminating the first nonwoven mat, the laid scrim, and the second nonwoven mat together to form the composite reinforcement.

Embodiment 2

A roofing membrane including a composite reinforcement impregnated with an asphaltic composition, wherein the composite reinforcement includes a first nonwoven mat, a laid scrim overlying the first nonwoven mat, where the laid scrim includes a first plurality of yarns substantially oriented in a first direction and a second plurality of yarns substantially oriented in a second direction different from the first direction, where the second plurality of yarns includes at least one different material from the first plurality of yarns and where each of the yarns in the second plurality of yarns includes a tension greater than a tension of each of the yarns in the first plurality of yarns, a second nonwoven mat overlying the laid scrim, and a binder laminating the first nonwoven mat, the laid scrim, and the second nonwoven mat together to form the composite reinforcement.

Embodiment 3

A composite reinforcement configured for incorporation into a roofing membrane, wherein the composite reinforcement includes a polyester nonwoven mat, a laid scrim overlying the polyester nonwoven mat, wherein the laid scrim includes a plurality of fiberglass yarns oriented in a cross direction of the laid scrim and a plurality of polyester yarns and fiberglass yarns oriented in a main direction of the laid scrim, and wherein each of the polyester yarns and fiberglass yarns oriented in the main direction includes a tension greater than a tension of each of the fiberglass yarns oriented in the cross direction, a fiberglass nonwoven mat overlying the laid scrim, and a binder laminating the polyester nonwoven mat, the laid scrim, and the fiberglass nonwoven mat together to form the composite reinforcement.

Embodiment 4

A method of forming a composite reinforcement, the method including coating a laid scrim with a binder, wherein the laid scrim includes a first plurality of yarns substantially oriented in a first direction and a second plurality of yarns substantially oriented in a second direction different from the first direction, wherein the second plurality of yarns includes at least one different material from the first plurality of yarns and wherein each of the yarns in the second plurality of yarns includes a tension greater than a tension of each of the yarns in the first plurality of yarns, contacting the laid scrim with a first nonwoven mat and a second nonwoven mat, wherein the laid scrim overlies the first nonwoven mat and wherein the second nonwoven mat overlies the laid scrim; and curing the binder to form the composite reinforcement.

Embodiment 5

The composite reinforcement or method of any one of embodiments 1, 2, and 4, wherein the first nonwoven mat includes polyester fibers.

Embodiment 6

The composite reinforcement or method of any one of embodiments 1, 2, and 4, wherein the first nonwoven mat consists essentially of polyester fibers.

Embodiment 7

The composite reinforcement of embodiment 3, wherein the polyester nonwoven mat consists essentially of polyester fibers.

Embodiment 8

The composite reinforcement or method of any one of embodiments 1, 2, and 4, wherein the second nonwoven mat includes fiberglass fibers.

Embodiment 9

The composite reinforcement or method of any one of embodiments 1, 2, and 4, wherein the second nonwoven mat consists essentially of fiberglass fibers.

Embodiment 10

The composite reinforcement of embodiment 3, wherein the fiberglass nonwoven mat consists essentially of fiberglass fibers.

Embodiment 11

The composite reinforcement or method of any one of embodiments 1, 2, and 4, wherein the first plurality of yarns includes fiberglass yarns.

Embodiment 12

The composite reinforcement of any one of embodiments 1, 2, and 4, wherein the first plurality of yarns consists essentially of fiberglass yarns.

Embodiment 13

The composite reinforcement or method of any one of embodiments 1, 2, and 4, wherein the second plurality of yarns includes polyester yarns and fiberglass yarns.

Embodiment 14

The composite reinforcement or method of any one of embodiments 1, 2, and 4, wherein the second plurality of yarns consists essentially of polyester yarns.

Embodiment 15

The composite reinforcement or method of any one of embodiments 1, 2, and 4, wherein the first direction is a cross direction of the laid scrim and the second direction is a main direction of the laid scrim, and wherein the first plurality of yarns is substantially oriented in the cross direction and wherein the second plurality of yarns is substantially oriented in the main direction.

Embodiment 16

The composite reinforcement or method of embodiment 15, wherein the cross direction includes between about 1 yarn per inch and about 12 yarns per inch, and wherein the main direction includes between about 1 yarn per inch and about 12 yarns per inch.

Embodiment 17

The composite reinforcement of embodiment 15, wherein the first plurality of yarns includes fiberglass yarns and wherein the second plurality of yarns includes polyester yarns and fiberglass yarns.

Embodiment 18

The composite reinforcement of embodiment 15, wherein the first plurality of yarns consists essentially of fiberglass yarns and wherein the second plurality of yarns consists essentially of polyester yarns.

Embodiment 19

The composite reinforcement or method of any one of embodiments 1, 2, 3, and 4, wherein the binder includes styrene-butadiene rubber.

Embodiment 20

The composite reinforcement or method of any one of embodiments 1, 2, and 4, wherein the binder penetrates at least a portion of the second nonwoven mat without saturating the second nonwoven mat.

Embodiment 21

The composite reinforcement of embodiment 3, wherein the binder penetrates at least a portion of the fiberglass nonwoven mat without saturating the fiberglass nonwoven mat.

Embodiment 22

The composite reinforcement or method of any one of embodiments 1, 2, and 4, wherein the laid scrim includes a greater concentration of binder than the first nonwoven mat or the second nonwoven mat.

Embodiment 23

The composite reinforcement of embodiment 3, wherein the laid scrim includes a greater concentration of binder than the polyester nonwoven mat or the fiberglass nonwoven mat.

Embodiment 24

The composite reinforcement or method of any one of embodiments 1, 2, and 4, wherein the second plurality of yarns includes a first yarn and a second yarn, and wherein the first yarn includes a greater concentration of binder than the second yarn.

Embodiment 25

The composite reinforcement or method of embodiment 24, wherein the first plurality of yarns includes a third yarn, and wherein the third yarn includes a greater concentration of binder than the second yarn.

Embodiment 26

The composite reinforcement of embodiment 3, wherein a polyester yarn from the plurality of polyester yarns and fiberglass yarns oriented in the main direction includes a greater concentration of binder than a fiberglass yarn from the plurality of polyester yarns and fiberglass yarns.

Embodiment 27

The composite reinforcement of embodiment 26, wherein a fiberglass yarn from the plurality of fiberglass yarns oriented in the cross direction includes a greater concentration of binder than the fiberglass yarn from the plurality of polyester yarns and fiberglass yarns oriented in the main direction.

Embodiment 28

The composite reinforcement or method of any one of embodiments 1, 2, and 4, wherein the tension of each of the yarns of the second plurality of yarns includes a tension between about 1.0 cN/tex and about 18 cN/tex.

Embodiment 29

The composite reinforcement of embodiment 24, wherein a tension of the first yarn is greater than a tension of the second yarn.

Embodiment 30

The composite reinforcement of embodiment 26, wherein a tension of the polyester yarn is greater than a tension of the fiberglass yarn.

Embodiment 31

The composite reinforcement of any one of embodiments 1, 2, and 4, wherein the tension of each of the yarns of the first plurality of yarns includes a tension of about 0 cN/tex.

Embodiment 32

The composite reinforcement of embodiment 3, wherein the tension of each of the fiberglass yarns oriented in the cross direction includes a tension of about 0 cN/tex.

Embodiment 33

The composite reinforcement or method of any one of embodiments 1, 2, 3, and 4, wherein the laid scrim includes a 0/90 laid scrim.

Embodiment 34

The composite reinforcement of any one of embodiments 1 and 2, wherein the tension of at least some of the yarns in the second plurality of yarns is configured to be relieved.

Embodiment 35

The composite reinforcement of embodiment 34, wherein the tension is configured to be relieved when the composite reinforcement is exposed to temperatures of at least approximately 35° C.

Embodiment 36

The composite reinforcement of embodiment 34, wherein the tension is configured to be relieved by shrinkage of the at least some of the yarns.

Embodiment 37

The composite reinforcement of embodiment 36, wherein the shrinkage occurs in a direction parallel to the second direction.

Embodiment 38

The composite reinforcement of embodiment 36, wherein the shrinkage includes a shortening of each of the at least some of the yarns in the second plurality of yarns.

Embodiment 39

The composite reinforcement of embodiment 38, wherein each of the at least some of the yarns in the second plurality of yarns includes a shortening of at least between 0.2% and about 15%.

Embodiment 40

The composite reinforcement of embodiment 3, wherein the tension of each of the polyester yarns oriented in the main direction is configured to be relieved.

Embodiment 41

The composite reinforcement of embodiment 40, wherein the tension is configured to be relieved when the composite reinforcement is exposed to temperatures of at least approximately 35° C.

Embodiment 42

The composite reinforcement of embodiment 40, wherein the tension is configured to be relieved by shrinkage of each of the polyester yarns.

Embodiment 43

The composite reinforcement of embodiment 42, wherein the shrinkage occurs in a direction parallel to the main direction.

Embodiment 44

The composite reinforcement of embodiment 42, wherein the shrinkage includes a shortening of each of the polyester yarns.

Embodiment 45

The composite reinforcement of embodiment 44, wherein each of the polyester yarns includes a shortening of at least between 0.2% and about 15%.

Embodiment 46

The method of embodiment 4, further including forming the laid scrim.

Embodiment 47

The method of embodiment 46, wherein the second plurality of yarns includes a first group of yarns and a second group of yarns, wherein forming the laid scrim further includes laying the first plurality of yarns between the first group of yarns and the second group of yarns.

Embodiment 48

The method of embodiment 46, wherein the tension is applied to each of the yarns in the second plurality of yarns while the laid scrim is being formed.

Embodiment 49

The method of embodiment 4, wherein curing further includes setting the tension of each of the yarns in the second plurality of yarns.

Embodiment 50

The method of embodiment 4, wherein coating includes dip coating.

Embodiment 51

The method of embodiment 4, further including removing excess binder from the laid scrim before the laid scrim contacts the first nonwoven mat and the second nonwoven mat.

Embodiment 52

The method of embodiment 4, further including relieving the tension of at least some of the yarns in the second plurality of yarns.

Embodiment 53

The method of embodiment 52, wherein the tension is relieved when the composite reinforcement is exposed to temperatures of at least approximately 35° C.

Embodiment 54

The method of embodiment 52, wherein the tension is configured to be relieved by shrinkage of the at least some of the yarns.

Embodiment 55

The method of embodiment 54, wherein the shrinkage occurs in a direction parallel to the second direction.

Embodiment 56

The method of embodiment 54, wherein the shrinkage includes a shortening of each of the at least some of the yarns in the second plurality of yarns.

Embodiment 57

The method of embodiment 56, wherein each of the at least some of the yarns in the second plurality of yarns includes a shortening of at least between 0.2% and about 15%.

Embodiment 58

A method of preventing a distortion on a roofing surface, the method including applying a roofing membrane to the roofing surface, the roofing membrane including a composite reinforcement, wherein the composite reinforcement includes: a first nonwoven mat, a laid scrim overlying the first nonwoven mat, wherein the laid scrim includes a first plurality of yarns substantially oriented in a first direction and a second plurality of yarns substantially oriented in a second direction different from the first direction, wherein the second plurality of yarns includes at least one different material from the first plurality of yarns and wherein each of the yarns in the second plurality of yarns includes a tension greater than a tension of each of the yarns in the first plurality of yarns, a second nonwoven mat overlying the laid scrim, and a binder laminating the first nonwoven mat, the laid scrim, and the second nonwoven mat together to form the composite reinforcement, exposing the roofing membrane to an environmental condition, relieving the tension of at least some of the yarns in the second plurality of yarns in response to the environmental condition; and preventing the distortion on the roofing surface.

EXAMPLES

The following examples are provided to better disclose and teach processes and compositions of the present invention. They are for illustrative purposes only, and it must be acknowledged that minor variations and changes can be made without materially affecting the spirit and scope of the invention as recited in the claims that follow.

Example 1

The scrims described herein can include shrinkable material to assist in counteracting the effects of dimensional expansion within a composite reinforcement. As also described herein (e.g., in FIG. 3), not only can the amount of tension applied to a yarn made of shrinkable material be tailored, the amount of future shrinkage experienced by the shrinkable material also can be predicted and tailored. The ability to predict and tailor future shrinkage of the scrim by tailoring the amount of tension applied to the shrinkable material in the scrim enables the scrim (and the composite reinforcement) to be specifically designed to counteract dimensional expansion, and deformation, in particular geographical settings or environmental conditions.
Portions of two composite reinforcements were tested to analyze the effect of different tensions on the expansion and contraction behavior of the scrim. In a first composite reinforcement, a first plurality of yarns of the scrim include fiberglass yarns and a second plurality of yarns of the scrim include the shrinkable material of lower shrinkage polyester yarns with a lower tension (e.g., approximately 4.5 cN/tex) applied to the shrinkable material (e.g., a lower tension applied to each of the yarns). Sample A was taken from a portion of the first composite reinforcement. In a second composite reinforcement, a first plurality of yarns of the scrim include fiberglass yarns and a second plurality of yarns of the scrim include the shrinkable material of the same lower shrinkage polyester yarns, but a higher tension (e.g., approximately 7.7 cN/tex) was applied to each of the yarns made of the shrinkable material. Sample B was taken from a portion of the second composite reinforcement.
FIG. 5 depicts a graph of composite reinforcement displacement in accordance with an embodiment described herein. For the first 15 minutes of the test, the Samples were heated. After 15 minutes, the heat was removed and the Samples returned to an ambient temperature. As the Samples were heated over the first 2-3 minutes of the test, each of the Samples experienced a positive displacement or dimensional expansion (e.g., lengthening of at least some of the yarns in the scrims) in response to the heat. When each of the Samples reached a maximum positive displacement, the tendency of the shrinkable material to shrink or contract in response to the dimensional expansion began to cause each of the Samples to reduce their positive displacement. Sample A contracted such that it had approximately no net displacement after 15 minutes of heating, while Sample B contracted to a greater degree, leaving Sample B with a net negative displacement of approximately 10 mils after 15 minutes of heating. Once the heat was removed at 15 minutes, each of the Samples experienced further negative displacement as a result of the continued contraction of the shrinkable material, the reversible thermal expansion of the shrinkable material while cooling, and the cooling of the Sample. After 15 minutes of cooling (e.g., at 30 minutes), Sample A exhibited a net negative displacement of approximately 10 mils, while Sample B exhibited a net negative displacement of approximately 20 mils. On average, Sample B (with the greater tension applied to the shrinkable material), exhibited approximately 10 mils more shrinkage than Sample A. As such, the first composite reinforcement from which Sample A was taken can be predicted to exhibit less shrinkage or contraction, which behavior may be desirable in certain instances or applications. For example, this composite reinforcement may be useful in a cold adhesive application, where products should desirably exhibit complete compensation for a thermal expansion after approximately 15 minutes of exposure to a heat source. As shown in FIG. 5, the thermal expansion experienced by Sample A was desirably reversed after 15 minutes of heating. The second composite reinforcement, from which Sample B was taken, can be predicted to exhibit more shrinkage or contraction, which behavior may be desirable in other instances or applications. Therefore, by tailoring in advance the tension applied to the shrinkable material, the future shrinkage behavior of the scrim can be predicted, which can enable the scrim (and the composite reinforcement) to be specifically designed to counteract dimensional expansion, and deformation, in particular geographical settings or environmental conditions. In contrast, a conventional reinforcement that does not contain a second plurality of yarns under tension will nevertheless have thermal expansion during the first 15 minutes of exposure to the thermal condition and provide defects that remain as a positive displacement, or elongation, of at least about 20 mil.

Example 2

The composite reinforcements described herein are configured to be incorporated into other structures. For example, when used to create a roofing membrane, the composite reinforcement is impregnated (e.g., permeated) with an asphaltic composition, such as an asphaltic rubber composition. The manner and location(s) in which the binder is distributed within one or more layers of the composite reinforcement, however, can maximize the air permeability of that layer, which in turn leads to an increased ability to permeate the reinforcement with asphalt.
FIG. 6 depicts a graph of composite reinforcement air permeability in accordance with an embodiment described herein. Air permeability is measured to assess how well the composite reinforcement can be impregnated by an asphaltic composition. Higher air permeability indicates that the composite reinforcement is more likely to be fully impregnated by the asphaltic composition. Successful impregnation of the layers in the composite reinforcement by the asphaltic composition can lead to greater interlaminar strength within the reinforcement (e.g., less delamination between the layers of the composite reinforcement) and increased peel strength of the resulting roofing membrane. Sample X was taken from a composite reinforcement that was coated with a binder in accordance with the unsaturated method or technique described herein. Sample Y was taken from a composite reinforcement that was coated in accordance with the saturated method or technique described herein. The air permeability of both Samples was obtained in units of cubic feet of air per minute per square foot (CFM). The air permeability of Sample X was 316 CFM, while the air permeability of Sample Y was 259 CFM. Greater air permeability in Sample X indicates that a composite reinforcement coated with binder by the unsaturated coating technique desirably can be more fully permeated by an asphaltic composition than a composite reinforcement coated by the saturated coating technique.
The composite reinforcement of the present invention represents a departure from and improvement over conventional reinforcements, particularly for roofing applications. Conventional reinforcements are prone to “mole running,” or dimensional expansion along the length of the reinforcement, which can cause deformation of the reinforcement at one or more points where the roofing membrane is weakly adhered to the roof. Conventional reinforcements also are prone to “dog legging,” or skewing of an otherwise balanced fabric. By contrast, the composite reinforcement of the present invention can be tailored to avoid both of these phenomena. Through proper selection of one or more shrinkable materials (depending on the specific conditions to which the composite reinforcement will be exposed) and proper treatment of those materials during manufacturing (e.g., by the variable application of tension and/or heat to the materials), the composite reinforcement described herein can resist skewing of layers within the reinforcement and overall deformation of the reinforcement.
Certain features, for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any subcombination. Further, reference to values stated in ranges includes each and every value within that range.
Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any feature(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature of any or all the claims.
The specification and illustrations of the embodiments described herein are intended to provide a general understanding of the structure of the various embodiments. The specification and illustrations are not intended to serve as an exhaustive and comprehensive description of all of the elements and features of apparatus and systems that use the structures or methods described herein. Separate embodiments may also be provided in combination in a single embodiment, and conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any subcombination. Further, reference to values stated in ranges includes each and every value within that range. Many other embodiments may be apparent to skilled artisans only after reading this specification. Other embodiments may be used and derived from the disclosure, such that a structural substitution, logical substitution, or another change may be made without departing from the scope of the disclosure. Accordingly, the disclosure is to be regarded as illustrative rather than restrictive.

Claims

What is claimed is:

1. A composite reinforcement comprising:

a first nonwoven mat;

a laid scrim overlying the first nonwoven mat, wherein the laid scrim comprises a first plurality of yarns substantially oriented in a first direction and a second plurality of yarns substantially oriented in a second direction different from the first direction, wherein the second plurality of yarns comprises at least one different material from the first plurality of yarns and wherein each of the yarns in the second plurality of yarns comprises a tension greater than a tension of each of the yarns in the first plurality of yarns;

a second nonwoven mat overlying the laid scrim; and

a binder laminating the first nonwoven mat, the laid scrim, and the second nonwoven mat together to form the composite reinforcement.

2. The composite reinforcement of claim 1, wherein the first nonwoven mat comprises polyester fibers.

3. The composite reinforcement of claim 1, wherein the second nonwoven mat comprises fiberglass fibers.

4. The composite reinforcement of claim 1, wherein the first plurality of yarns comprises fiberglass yarns.

5. The composite reinforcement of claim 1, wherein the second plurality of yarns comprises polyester yarns and fiberglass yarns.

6. The composite reinforcement of claim 1, wherein the first direction is a cross direction of the laid scrim and the second direction is a main direction of the laid scrim, and wherein the first plurality of yarns is substantially oriented in the cross direction and wherein the second plurality of yarns is substantially oriented in the main direction.

7. The composite reinforcement of claim 1, wherein the binder penetrates at least a portion of the second nonwoven mat without saturating the second nonwoven mat.

8. The composite reinforcement of claim 1, wherein the laid scrim comprises a greater concentration of binder than the first nonwoven mat or the second nonwoven mat.

9. The composite reinforcement of claim 1, wherein the tension of each of the yarns of the second plurality of yarns comprises a tension between about 1.0 cN/tex and about 18 cN/tex.

10. The composite reinforcement of claim 1, wherein the tension of at least some of the yarns in the second plurality of yarns is configured to be relieved by shrinkage of the at least some of the yarns, wherein the shrinkage occurs in a direction parallel to the second direction.

11. The composite reinforcement of claim 10, wherein the shrinkage comprises a shortening of each of the at least some of the yarns in the second plurality of yarns, wherein the shortening comprises at least between 0.2% and about 15%.

12. A composite reinforcement configured for incorporation into a roofing membrane, wherein the composite reinforcement comprises:

a polyester nonwoven mat;

a laid scrim overlying the polyester nonwoven mat, wherein the laid scrim comprises a plurality of fiberglass yarns oriented in a cross direction of the laid scrim and a plurality of polyester yarns and fiberglass yarns oriented in a main direction of the laid scrim, and wherein each of the polyester yarns and fiberglass yarns oriented in the main direction comprises a tension greater than a tension of each of the fiberglass yarns oriented in the cross direction;

a fiberglass nonwoven mat overlying the laid scrim; and

a binder laminating the polyester nonwoven mat, the laid scrim, and the fiberglass nonwoven mat together to form the composite reinforcement.

13. A method of forming a composite reinforcement, the method comprising:

coating a laid scrim with a binder, wherein the laid scrim comprises a first plurality of yarns substantially oriented in a first direction and a second plurality of yarns substantially oriented in a second direction different from the first direction, wherein the second plurality of yarns comprises at least one different material from the first plurality of yarns and wherein each of the yarns in the second plurality of yarns comprises a tension greater than a tension of each of the yarns in the first plurality of yarns;

contacting the laid scrim with a first nonwoven mat and a second nonwoven mat, wherein the laid scrim overlies the first nonwoven mat and wherein the second nonwoven mat overlies the laid scrim; and

curing the binder to form the composite reinforcement.

14. The method of claim 13, further comprising relieving the tension of at least some of the yarns in the second plurality of yarns, wherein the tension is configured to be relieved by shrinkage of the at least some of the yarns, wherein the shrinkage occurs in a direction parallel to the second direction.

15. The method of claim 14, wherein the shrinkage comprises a shortening of each of the at least some of the yarns in the second plurality of yarns, wherein the shortening comprises at least between 0.2% and about 15%.