MXPA06008613A - Sunscreen fabric and method of making same - Google Patents

Abstract

A sunscreen fabric for use in window coverings and the like is described. The fabric has a knit substrate which is coated with a substantially transparent coating which provides the fabric with good stability to enable it to be used as window shades such as roller shades and the like. The fabric also has good resistance to mark-off as well as cup/curl.

Description

(88) Date f publication f the intemational search report: ":: -" .-- .. "'• = -.-.; • .'- -. E 6May2006 PROTECTIVE SHUTTER FABRIC AND METHOD TO MANUFACTURE THE SAME FIELD AND BACKGROUND OF THE INVENTION Shutters or screens that protect from the sun such as window blinds are often used to provide protection from the sun's rays and glare caused by those rays. , the window screens must also be typically flame resistant (ie, have an FR efficiency) and have sufficient rigidity to hang properly on the window or from another structure where it is used (eg, not twisted or warped) and in In many cases, it can withstand being rolled up or down by a screen mechanism.To achieve these goals, screen fabrics are generally made of fabrics that are woven of polyester or fiberglass yarns coated with vinyl. ilo, which are laminated. While they provide a level of filtration, these previous screen materials are limited in terms of aesthetics. On the one hand, because the vinyl siding is opaque, the color of the screens is determined by the color of the vinyl siding of the threads, and then the available color pallet is typically limited. In addition, the construction of the fabric is limited to conventional open-wave patterns. In addition, the vinyl siding should be sufficient to prevent the edges of the woven fabric from unraveling or fraying. BRIEF DESCRIPTION OF THE INVENTION The present invention is directed to a sun shade cloth having virtually unlimited aesthetic potential, which diffuses light better than prior art vinyl or glass fiber coated screen fabrics, and that they can be cut and manufactured without fraying or that they have to use anti-fraying or anti-fraying before cutting. Protective blind fabrics include base woven fabrics that can be dyed, printed or colored in any way or with patterns in a conventional manner. The fabric is coated with a urethane coating that provides good hardness and resistance to widening or waviness. The fabric also has comparable FR performance when compared to previous screen materials. In addition, the fabrics of the invention have a high resistance to markings, and do not have the environmental disadvantages associated with the vinyls used in conventional screen materials. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a diagram of the stitching of the fabric described in Example B; Fig. 2 is a diagram of the stitching of the fabric described in Example C; Figure 3 is a schematic illustration of a process according to the present invention. Figure 4A and 4B are explored pieces of the fabric; Figure 5 is a perspective view of a rolled screen; and Figure 6 is a scanned piece of the fabric. BRIEF DESCRIPTION OF THE INVENTION In the following detailed description of the invention, the specific preferred embodiments of the invention are described to allow a complete and complete understanding of the invention. It will be recognized that it is not intended to limit the invention to the particular described preferred embodiment, and while specific terms are employed in describing the invention, such terms are used in a descriptive sense for the purpose of illustration and not for the purpose of limitation. The fabrics of the invention have a woven base fabric which is preferably an embroidered knit construction, such as a raschel or knit fabric. The fabric is preferably at least a two-bar construction, although it can be made of three bars, four bars, etc., depending on the complexity desired for the pattern. The fabric is preferably constructed to have from about 2% to about 25% aperture (defined as the amount of open space relative to the area of the total fabric). As will be easily appreciated by those of ordinary skill in the art, the aperture level can be selected to adjust the amount of light you want to pass through, the amount of protection desired, etc. For example, screens designed to be used in windows on the side facing the sun, of a building, can be designed to be less open, while those for the dark or shaded side of a building can be designed to be more open, to allow more natural light to enter the room. An advantage of knitted or knitted fabric construction is that it can be designed to provide a particular aesthetic appearance, and can be constructed to provide different appearances on each of the fabric surfaces. In addition, complex fabrics such as the jacquard construction can be used to provide additional aesthetic characteristics. In addition, it has been found that a larger thickness of the fabric promotes an absorption of light, then desirably the size of the yarn and the thickness of the fabric will be selected to achieve the desired level of absorption.

The woven fabric can be made of any desired yarn. For example, it may be made of synthetic and / or natural fibers, including but not limited to polyester, nylon, acetate, rayon, cotton, spun, olefins (eg, polypropylene) or the like, or mixtures or combinations thereof. same. However, the polyester filament is preferred since it has been found to withstand UV degradation well. However, other fibers can also be used as long as they are treated to improve their UV resistance, FR operation, or the like as required. For example, fibers having inherent FR characteristics can be used. Where polyester is used, FR polyester can be used, or a non-FR polyester can be treated with a conventional FR treatment. In addition, the yarns may be spun or filaments, flat or textured yarns, or combinations thereof. When desired, the fabric can be dyed to the desired color and dye, such as by a conventional dyeing process (e.g., jet dyeing, tank dyeing, pad dyeing, positioning dyeing, etc.) For example, where The woven fabric is polyester, it has been found that a jet dyeing process works well. Alternatively, the fabric can be woven from yarns that are the desired color for the final fabric, such as dyed solution or threads dyed with yarns. As a further alternative, the fabric may have patterns in addition to or in lieu of a dyeing process, such as printing, embossing, a thermal pattern treatment process, fluid pattern treatment processes, or the like, or a combination thereof. same. For example, in one embodiment of the invention, a yarn dyed with black solution is included, to facilitate the absorption of light. The base color of the fabric can also be adjusted to facilitate the achievement of the desired level of absorption. The fabric can also be treated with additional chemicals if desired, including but not limited to flame retardants, UV inhibitors or absorbers, antimicrobials, antifungals or mold inhibitors, water repellents, dust release chemicals, polychromatic chemicals, odor absorbers. , formaldehyde absorbers or the like. Where chemicals are used, they can be applied separately or simultaneously with dyeing, where a dyed process is used. For example, in one embodiment of the invention, a jet-dyed polyester fabric with a flame retardant that is added to the dyeing jet during dyeing. Examples of commercially available flame retardants are Flameproof 1503 from Apex Chemical of South Carolina and Pyrozyl EF-9® available from A itech, Inc. It has been found that by depleting the flame retardant in the fiber in this way it improves its permanence in the cloth. The fabric is then desirably coated with a urethane coating, to provide the fabric with additional stiffness. For example, in a preferred form of the invention, urethane coating is of the variety described in the commonly assigned North American patent application for "Finishing and Process for Creating Flame Retardant Textures that Resist the Tracing" of Amott, presented on March 26, 2004, the subject matter of which is incorporated herein by reference. It has been found that this • coating provides good marking or tracing resistance, unlike most conventional urethane coatings. (As will be readily appreciated by those with ordinary skill in the art, "trace" or "mark" refers to visible defects exhibited by a finished or coated fabric when a contact or localized force is applied (e.g., when scraped) , resulting in the cracking of the polymer finish or a separation of the textile polymer's finish, either of which leads to visible lines of scratch in the contact area or localized force). Specifically, the coating is a combination of a first urethane polymer having a breaking elongation greater than or equal to 500% and a second urethane polymer having a breaking elongation of less than 500%, wherein the ratio of the first urethane polymer to the second urethane polymer is about 10: 1 on a solids basis. Preferably, the first and second urethane polymers are either aliphatic polyesters, aliphatic polyethers, or a combination thereof. In a particularly preferred embodiment of the invention, both urethane polymers are aliphatic polyesters. The urethane coating may also include such things as flame retardants, chemicals designed to enhance UV absorption, UV inhibitors, antimicrobials, antifungals or anti-mildew, water repellents, dust-releasing chemicals, polychromatic chemicals, odor absorbers, formaldehyde absorbents or similar. Preferably, the coating is substantially transparent (i.e., does not mask the appearance of the fabric to a significant degree), does not yellow, and does not contain appreciable amounts of formaldehyde. Where a flame retardant is incorporated, it is preferably incorporated in the molecular backbone of at least one of the urethane polymers. In a preferred form of the invention, the first urethane polymer has a hardness of between about 5 and about 25 on a Sward Roc erd hardness scale, and the second urethane polymer has a hardness greater than about 25 on a hardness scale. Sward Rocker. The aggregate level of dryness of the polymer finish is desirably in the range of about 2% to about 15%, and even more preferably in the range of about 3% to about 5%. Specifically, the urethane coating is desirably one that provides a transparent hand-held adjuvant finish, which is not yellow, free of formaldehyde and does not show marks or strokes. In addition, the urethane coating desirably can be applied at a low level of addition so as to maintain a nice hand on the fabric. The coating can be applied in any conventional manner, such as by padding, spray coating, foam coating, knife-on-roll, printing, soft coating or the like. The coating is preferably applied as a continuous coating, although it can be applied discontinuously (e.g., in a pattern) if desired. Following the coating, the fabric is desirably dried in a conventional manner. For roller screens and Roman screens, it has been found that fabrics that have a finished weight of about 9 to about 13 oz / square yard work well. An advantage of the fabrics of the invention is that they are resistant to fraying of the edges, and does not require the use of anti-fraying spray when they are cut and manufactured. Therefore they can be used for indoor or outdoor advantage screens (protectors) for domestic or commercial use, and can also be provided in commercial size products where they are cut to size in the store (for example, such as in a store for the improvement of the house). Another advantage is that the coatings of the invention allow the appearance of the fabric to be easily visible. In addition, unlike many plastic-type coatings, the coating is designed to minimize "marking". Typically, people in the textile industry will test the marking by scraping with their fingernail across the surface of the fabric and observing if a mark is left, or quilting the fabric and smoothing it again, noting if the colored marks left by the light are left where the fabric is pleated. Since the lighter colored light rays are a result of the variation in the reflectance of light along the pleated or wrinkled portion, the marking may be a particular problem in the darker colored fabrics that are coated. While specifically discussed in connection with screens (such as roller screens and Roman screens), it is noted that the fabrics of the invention can also be used to produce other types of window coverings., including but not limited to folded screens, cellular screens, vertical blinds, awnings or canopies, shade screens and room dividers and the like. The window coverings made in accordance with the invention can be used in virtually any application, including but not limited to buildings (commercial and residential), vehicles (automobiles, buses, airplanes, RVs, trailers, boats, boats, etc.). , and similar. In many end uses it will be desirable that the sunscreen fabrics have FR characteristics. These may be inherent in the fibers selected and used, or they may be obtained or supplemented through additional chemical treatments applied before, or at the same time, or after the coating of the fabric. EXAMPLES Example A - A conventional, woven, bone colored roller protection fabric was obtained.

Example B - A cream colored fabric according to the invention was prepared as follows. A fabric was woven in a 56-gauge raschel machine using 4 guide bars in the configuration illustrated in figure 1. (Note that it could also be woven in a single-needle warp knitting machine using 4 guide bars .) The machine was loaded with 4 bundles of threads with beam # 1 containing 1438 Dacron polyester ends 150/34 56WD.SD, beam # 2 containing 1438 Dacron polyester ends of 150/34 56 D SD, beam # 3 containing 1440 Dacron polyester ends of 100/34 56 D SD and beam # 4 containing 1439 Dacron polyester ends of 150/34 WD SD. In this fabric, bar # • 1 is threaded 1 in, 1 out; bar # 2 is threaded 1 in, 1 out; bar # 3 and bar # 4 are completely threaded. The fabric was processed in a tension frame to stabilize it for further processing. The initial tensor step involved moving the fabric through a water bath heated to 180 ° F (82.22 ° C), then drying in an oven at 198.89 ° C (390 ° F) at a processing speed of 13.72 meters ( 15 yards) per minute. The fabric was then subjected to a conventional jet dyeing process, using conventional disperse dyes and additives (e.g., defoamer, leveler, etc.). In addition, a minor amount (0.25% o.w.g.) of UV inhibitor was included, as well as a flame retardant (4% of Pyrozyl, available from Amitech of Oxford, NJ.). The fabric was then processed again on the tensioner for the purpose of achieving a state of equilibrium of the drying of the fabric. The second step of the tensioner involved moving the fabric through a vat of water heated to 43.33 ° C (110 ° F), then drying in an oven at 198.89 ° C (390 ° F) at a processing speed of 16.46 meters (18 yards) per minute. Example C - Another cream colored fabric according to the invention was produced in the same manner as in Example B, with the exception that the sewn pattern illustrated in Fig. 2 followed. METHODS D? TEST The following tests were performed by Matrix, Inc. of Mesa, Arizona in their solar laboratory according to ASHRAE Standard 74-1988. "Methods to measure the solar optical properties of materials". As will be readily appreciated by those of ordinary skill in the art, Matrix is the most commonly used test facility for the test fabrics of this variety. Shading Coefficient - The shading coefficients for heat absorption ", clear glass" and clear glass 1/8"were tested.

Opening factor - The amount of open space of the fabric. Transmission of visible light (Tv) - The percentage of visible light that passes through the fabric (tested from inside the building or structure). Solar Absorption (As) - The percentage of solar energy that the fabric absorbs. The objective will vary depending on where and how the fabric will be used. As will be appreciated by those of ordinary skill in the art, solar absorption will be affected by the color of the fabric. Solar Reflection (Rs) - The percentage of solar energy reflected by the fabric back to the window (that is, the heat that does not return to the room). Solar Transmission (Ts) - The percentage of solar energy that passes through the fabric. Flare / Ripple Test - A piece of 243.84 centimeters X 187.96 centimeters (96 X 74 inches) of the fabric is cut (on the longitudinal side extending in the width direction). A cuff is formed at the bottom and a bar of 2.27 kilograms (5 pounds) is inserted. The upper part of the fabric sticks to a wall and the fabric is left under ambient conditions of regular interiors. After 24 hours, the distance between the wall and the edges of the fabric is measured at the position at the edge which is the greatest distance from the wall. To be useful as a roller or a Roman screen, the widening / bending or curling at 243.84 centimeters (96 inches) in width should be about 20 mm or less. Marking - Marking was tested using a conventional wire thinning test apparatus. The methods involved taking a 130 mm diameter circular specimen specimen and installing the fabric test piece on the rotary table with a double sided tape. A knife edge with a weight of 1.96N was positioned, so that it makes contact with the fabric and the turntable is rotated twice at 1 rpm. After the test, the surface of the sample is observed and is rated between 1 and 5, with a "1" indicating extreme marking and an unacceptable fabric. A "5" shows that there are no visible marks. A rate of 3.5 or higher would be considered acceptable for most sun protection applications. Figure 4A illustrates a fabric having a "1" rate (extreme marking, illustrated in "MO"), while Fig. 4B is a scanned fabric having a marking rate of 4.5.

Table of results of the test As illustrated, the fabrics of the invention reach comparable levels of operation or sun protection relative to conventional material. In addition, using the knitted fabrics described herein, protective blinds can be made with different appearances on each side if desired. Also, the size of the hole can be designed to achieve the desired level of aperture, without sacrificing stability (as would be the case with woven screen fabrics). In addition, the protective blind fabrics made in accordance with the invention are resistant to thinning, so that they can be individualized to a desired width - without the need for additional scratch resistant mechanisms. Also, the fabrics have good spreading / crimping resistance, preferably less than about 20 mm, more preferably about 10 mm or less. For example, the fabrics of the examples have been shown to have approximately 6 mm of flare / ripple. As noted above, the protective screen fabrics of the invention are. they desirably secure a structure so that it can effectively protect or filter sunlight as desired. Fig. 5 illustrates a fabric of the invention secured to a support mechanism 24 to form a roller screen 20. The roller screen 20 is illustrated as having a pattern 22 on its surface. As noted, the pattern can be provided in a variety of ways, such as by forming it into a fabric structure, printing, stamping, a fluid pattern treatment process and / or a thermal pattern treatment process. As previously discussed, the generation of marks is more pronounced in dark colored fabrics than in light colored colored fabrics. While the samples listed in the table above are colored clear, additional samples were prepared in the same manner, although they were stained a dark color prior to the application of the polymeric coating. In those embodiments of the invention, the resistance to marking was even greater than 3.5 and in most cases, a larger 4.5. In the specification a preferred embodiment of the invention has been established, and although specific terms were used, they were used in a generic and descriptive sense and not only for purposes of limitation, the scope of the invention is defined in the claims.

Claims (25)

1. CLAIMS 1. A fabric for protection screen against the sun, characterized in that it comprises: an embroidered knitted fabric having at least a construction of two bars, and a polymeric coating applied to said fabric, wherein said polymeric coating comprises a polymer of urethane and the coated fabric exhibits a broadening / waviness of less than about 20 mm to 243.84 centimeters (96 inches) in width.
2. 2. A fabric according to claim 1, characterized in that said polymeric coating is substantially transparent.
3. 3. A fabric according to claim 1, characterized in that said fabric has an opening of about 2 to about 25%.
4. 4. A fabric according to claim 1, characterized in that said fabric has a resistance to marks of about 3.5 or greater.
5. 5. A fabric according to claim 1, characterized in that said fabric further comprises a flame retardant.
6. 6. A fabric according to claim 1, characterized in that said fabric is in the form of a window protector.
7. 7. A sun protection shutter, characterized in that it comprises: a knitted fabric, and a mechanism for securing said knitted fabric to a structure.
8. 8. A sun protection shutter according to claim 7, characterized in that said knitted fabric has an aperture of about 2% to about 25%.
9. 9. A sun protection shutter according to claim 7, characterized in that said fabric of. The point is coated with a polymer, and said coated fabric exhibits a widening / waviness of approximately 20 mm or less through 243.84 centimeters (96 inches) in width. A sun protection shutter according to claim 7, characterized in that said knitted fabric is coated with a polymer, and said coated fabric exhibits a marking strength of about 3.5 or greater. 11. A sun protection shutter according to claim 7, characterized in that said knitted fabric is coated with a polymer selected from the group consisting of aliphatic polyesters, aliphatic polyethers and combinations thereof. 12. A sun protection shutter according to claim 7, characterized in that said knitted fabric is an embroidered knitted fabric having at least a construction of two rods. 13. A sun protection shutter according to claim 7, characterized in that the knitted fabric is a knitted fabric selected from the group consisting of warp knit and raschel knits. A sun protection shutter according to claim 7, characterized in that said knitted fabric has an opening of about 2 to about 25% and said knitted fabric is coated with a polymer, wherein said coated fabric exhibits a widening / Ripple of approximately 20 mm or less through 243.84 centimeters (96 inches) in width when tested in accordance with a spreading / ripple test, and a marking or marking strength of approximately 3.5 or greater. 15. A sun protection shutter according to claim 7, characterized in that said knitted fabric is coated with a substantially transparent polymer coating. 16. A sun protection shutter according to claim 7, characterized in that said knitted fabric includes a pattern. 17. A sun protection shutter according to claim 16, characterized in that said pattern is defined by a private pattern, a stamping pattern, a thermal pattern or a fluid treatment pattern. 18. A sun protection shutter according to claim 7, characterized in that said knitted fabric defines first and second surfaces., and the first surface of the fabric has a visual appearance that is different from that of the second surface. 19. A sun protection shutter according to claim 7, characterized in that said fabric and mechanism defines a sun blind in a shape of the group consisting of roller screens, Roman screens, folded screens, awnings or canopies, cellular screens, curtains or vertical screens, umbrellas, room blinds and dividers. A method for manufacturing a sun blind fabric, characterized in that it comprises the steps of: providing an embroidered knitted fabric having at least a two-bar construction, and coating said fabric with a liner comprising a combination of a first urethane polymer having a breaking elongation greater than or equal to 500% and a second urethane polymer having a breaking elongation of less than 500%, wherein the ratio of the first urethane polymer to said second urethane polymer is approximately 10: 1 on a solid base. 21. The method according to claim 20, characterized in that said fabric has an opening of about 2 to about 25%. 22. The method according to claim 20, characterized in that it further comprises the step of treating the fabric with a flame retardant. 23. The method according to claim 20, characterized in that it also comprises the step of dyeing the fabric. 24. The method according to claim 20, characterized in that it further comprises the step of providing the fabric with a pattern by a process selected from the group consisting of printing, thermal modification and fluid treatment. 25. The method according to claim 20, characterized in that it further comprises the step of securing the fabric to a mechanism for securing the fabric to a structure.