Title:
FLAME-RESISTANT TEXTILE FOUNDATION FABRIC
United States Patent 3861992
Abstract:
Foundation fabrics useful for tufted textile products and the like, which comprise a primary backing material having a web-like structure of self-extinguishing flame-resistant fibrous material attached to one surface thereof. Also disclosed are flame-resistant tufted carpets utilizing the foundation fabric.
US Patent References:
Fabrics
Sissors - October 1967 - 3348993
/3600261.html
Kerres - August 1971 - 3600261
Fabrics
Sissors - October 1967 - 3348993
/3600261.html
Kerres - August 1971 - 3600261
Inventors:
Denobriga, Frank H. (Kingsport, TN)
Neal, Richard D. (Kingsport, TN)
Neal, Richard D. (Kingsport, TN)
Application Number:
05/268968
Publication Date:
01/21/1975
Filing Date:
07/05/1972
View Patent Images:
Export Citation:
Assignee:
Eastman Kodak Company (Rochester, NY)
Primary Class:
Other Classes:
428/921, 428/96, 442/270
International Classes:
D04H13/00; D04H11/00; D03D27/00
Field of Search:
161/62,64,67,80,81,154,403,62-67
Primary Examiner:
Mccamish, Marion E.
Claims:
We claim
1. Textile foundation fabric for use as a primary backing for tufted carpets, said fabric having a web-like structure weighing from about 1 to 10 ounces/square yard and comprising self-extinguishing flame resistant fibrous material overlaying and attached to the surface thereof from which face yarns will extend when tufted into said fabric to locate said web-like structure between said fabric and the free ends of said tufted face yarn to form a flame barrier between said foundation fabric and said face yarn.
2. Foundation fabric of claim 1 wherein said flame-resistant material comprises material selected from the group of modacrylic fibers and polyvinyl chloride fibers.
3. Foundation fabric of claim 2, wherein said modacrylic fiber is copolymer of vinylidene chloride and acrylonitrile.
4. Foundation fabric of claim 2, wherein said modacrylic fiber is a copolymer of vinylidene chloride and acrylonitrile having mixed therein up to about 15 percent by weight of N-isopropylacrylamide.
5. Foundation fabric of claim 1, wherein said web-like structure is needle punched into said fabric.
6. Foundation fabric of claim 1, wherein said web-like structure is bonded to said fabric.
7. Foundation fabric of claim 1, wherein said self-extinguishing flame-resistant material has at least 0.5 percent by weight of antimony oxide incorporated therein.
8. Flame-resistant textile fabric comprising face yarn and the foundation fabric of claim 1.
1. Textile foundation fabric for use as a primary backing for tufted carpets, said fabric having a web-like structure weighing from about 1 to 10 ounces/square yard and comprising self-extinguishing flame resistant fibrous material overlaying and attached to the surface thereof from which face yarns will extend when tufted into said fabric to locate said web-like structure between said fabric and the free ends of said tufted face yarn to form a flame barrier between said foundation fabric and said face yarn.
2. Foundation fabric of claim 1 wherein said flame-resistant material comprises material selected from the group of modacrylic fibers and polyvinyl chloride fibers.
3. Foundation fabric of claim 2, wherein said modacrylic fiber is copolymer of vinylidene chloride and acrylonitrile.
4. Foundation fabric of claim 2, wherein said modacrylic fiber is a copolymer of vinylidene chloride and acrylonitrile having mixed therein up to about 15 percent by weight of N-isopropylacrylamide.
5. Foundation fabric of claim 1, wherein said web-like structure is needle punched into said fabric.
6. Foundation fabric of claim 1, wherein said web-like structure is bonded to said fabric.
7. Foundation fabric of claim 1, wherein said self-extinguishing flame-resistant material has at least 0.5 percent by weight of antimony oxide incorporated therein.
8. Flame-resistant textile fabric comprising face yarn and the foundation fabric of claim 1.
Description:
This invention relates to primary backing structures for tufted carpets which retard burning of primary backing, latex and secondary backing, if any, in a finished carpet, before and after washing, and result in an improved tunnel test rating for certain contract carpets. The backing structures of this invention may be jute or polypropylene foundation fabrics into which about 1 to 10 ounces/square yard self-extinguishing flame-resistant fibers have been needle punched or attached thereto by other means.
The novel primary backings of this invention exhibit unexpected flame-retarding characteristics for such low levels of self-extinguishing flame-resistant fibers. Preferred self-extinguishing flame-resistant fibers useful in the practice of our invention are modacrylic fibers such as DYNEL (copolymer of vinylidene chloride and acrylonitrile) and VEREL (copolymer of vinylidene chloride and acrylonitrile with about 15% by weight of N-isopropylacrylamide mixed therein) and polyvinyl chloride fibers. However, it is to be understood that other fibers having self-extinguishing flame-resistant properties and which when made into a web-like structure and attached to a foundation fabric will not unduly interfere with tufting, latex application and finishing operations on the finished carpet or the like.
Prior studies have shown that about 20 to 45 percent by weight of flame-retarding fiber must be used in blends with various carpet fibers to prevent burning of the pile in certain carpet styles such as twist set shags, friezes, etc. Thus a 30 ounce/square yard shag would contain 6 to 13.5 ounces/square yard of said fire-resistant fiber(s) in the pile yarn and a 45 ounce/square yard twist set shag would contain about 9 to 20.25 ounces/square yard.
The textile foundation fabric of this invention comprises a conventional primary carpet backing having attached to one surface thereof a web-like structure comprising self-extinguishing flame-resistant fibrous materials, the web-like structure weighing from about 1 to 10 ounces/square yard. The carpets prepared using the foundation fabric of this invention may be tufted in the conventional manner. When tufted the face yarn of the carpet will extend from and through the backing and through the web-like structure so that the web-like structure is located between the free or face surface of the face yarns and the primary backing thus forming in effect a fibrous barrier between the free ends of the tufts in the carpet and the primary backing material. It is not known why only 1 to 10 ounces/square yard of the fire-resistant fibrous web-like material is sufficient to prevent back burning even when relatively non-fire resistant or relatively low-grade fire-resistant latex is used, such as carboxylated SBR latex (CSBR), CSBR with only 150 parts alumina trihydrate, relatively low viscosity pre-dry latex (such as Gafcote R-367-N modified to contain only 100 parts alumina trihydrate).
Latex penetration into carpet backing structures is facilitated by this invention. Prior art backings such as spunbonded polypropylene and woven polypropylene into which nylon fiber has been needle punched are quite difficult to penetrate, at times producing unsatisfactory adhesion between the primary and secondary backings and other problems. Thus these prior art backings tend to have an adverse effect on the performance of fire-resistant latex with regard to both adhesion and/or fire-resistance characteristics, while our novel backing is quite compatible with fire-resistant latex systems. In fact, an advantage of our invention is compatibility with existing latex systems, particularly with polyester carpet yarns and prior art polypropylene primary backing as a foundation fabric.
Our novel backings improve the uniformity of tufted pile height by minimizing differential stitch robbing, particularly when jute and woven polypropylene foundation fabrics are used.
Modacrylic and polyvinyl chloride battings have been found to be easily needle punched as compared to other battings, such as nylon. Perhaps the lower toughness of modacrylic and polyvinyl chloride is one factor, but the reasons for this improvement are not understood. In addition, the backings of this invention are easy to penetrate in tufting and cause no difficulties in overheating and deflecting the needles as can be the case with nylon needle punched into woven polypropylene.
Our novel backings, by virtue of the effect of improved latex penetration and the mat-like structure, produce a pronounced internal-padding effect. Thus a contract carpet (3/16 inch pile, 30 ounces/square yard, for example) of stock-dyed polyester or nylon fiber has a fuller, more resilient feel, more uniform pile height, more uniform shearing, and better fire-resistance characteristics. Our invention provides a more rigid backing and superior total performance compared to prior art backings. The internal-padding effect also permits the carpet to be printed, if desired, without first applying a resilient foam-type secondary backing.
In piece-dyeing, the backings of this invention, particularly when dull modacrylic is used, tend to produce superior sinking characteristics in tufted carpets. This is an important performance advantage over prior art polypropylene backings (with and without needle punched nylon) which tend to be more difficult to sink. Furthermore, the use of silicone anti-foam in dyeing has far less detrimental effect from the standpoint of backing flammability when these novel backings are used compared to products of prior art. Indeed, this is surprising in view of the relatively small amount of fire-resistant fiber used. It is a major advantage to be able to use silicone-type products in appropriate amounts for piecedyeing certain carpet styles due to the superior anti-foaming performance. In addition, this invention makes non-silicone, anti-foam products more effective. There are many shag, frieze and other styles which should by dyed with non-silicone, anti-foam products.
Perhaps due to the ability to absorb water and/or other reasons, our novel backings, particularly with modacrylic fiber, have better anti-static properties than prior art backings that utilize needle punched nylon, particularly at 30 to 50 percent RH. Again, possibly due to water absorption, improved penetration and/or other reasons, better continuous dyeing is obtained with the backing of this invention than when spunbonded polypropylene and woven polypropylene with needle punched nylon are used.
When washed as prescribed in AATCC Method 124-1964 or as amended in order to test the permanence of the latex structure containing alumina trihydrate and/or other compounds, our novel backings demonstrate a remarkable ability to minimize damage to said latex structure. This is reflected in the tablet test results when the back burning characteristics of washed carpets (such as twist set shags, plushes, etc.) are observed in a comparison between our novel primary backings and the backings of prior art.
One embodiment of our invention consists of a foundation fabric, like jute, spunbonded polypropylene (such as Typar) or woven polypropylene (such as Polybac) into which batting-like or mat-like structures made of modacrylic and/or polyvinyl chloride fibers have been needle punched. In preferred embodiments, the batting-like structure weighs approximately 1 to 6 ounces/square yard; but, if desired, weights as high as 10 ounces/square yard can be used. Even at weights in the 6 to 10 ounce/square yard range, excellent needle punching and subsequent tufting can be obtained. Our novel backing can be used for a variety of carpets, including those which are piece-dyed, continuous dyed, stock-dyed or printed.
Alternatively, the aforementioned fibers can be attached to the foundation fabric by other means, such as bonding and curing the materials in a compressed state.
In preferred embodiments of our invention, the aforementioned modacrylic and polyvinyl chloride fibers would range from 1 to 20 D/F in staple lengths of about 1 to 4 inches. Also the fibers may have incorporated therein at least 0.5 percent by weight of antimony oxide.
It is recognized that for various practical reasons -- such as inventory, economics, operational characteristics and mechanical settings of the nonwoven equipment for producing the battings, etc. -- there could be a strong need to work-off various fibers by blending with the modacrylic and polyvinyl chloride fibers of our invention. Such practice is discouraged because it tends to reduce the flame-resistance of the novel carpet backing. However, if such blending procedure is employed, the additional fiber should not exceed roughly 25 percent of the total batting weight with at least 75 percent being composed of self-extinguishing flame-resistant fibers. In no case should there be less than about 1 ounce/square yard of self-extinguishing flame-resistant fiber used in such blends.
For a better understanding of this invention, reference is made to the following examples:
EXAMPLE 1
The following contract carpets were prepared using 2.7/3 c.c., 4.75Z/3S yarns made from 15 D/F x 6 inch poly(ethylene terephthalate) polyester on the worsted system:
A. a 30 ounce/square yard, 1/4 inch pile carpet was tufted using a woven polypropylene primary. Said primary weighed about 3.0 to 4.5 ounces/square yard.
B. a similar carpet was tufted using woven polypropylene foundation fabric into which about 4 ounces/square yard of 3 D/F dull Verel CA modacrylic fiber was needle punched.
C. a carpet similar to A was tufted using a woven polypropylene fabric into which was needle punched about 2 ounces/square yard of approximately 3 D/F nylon staple fiber.
Less needle deflection and needle heating occurred in tufting carpet B than tufting carpet C even though carpet B had a greater total material weight to be penetrated by the needles. Carpet B had better tuft uniformity than A or C. The three carpets were piece-dyed honey beige using silicone antifoam. Carpet B wet-out and sank more easily than the other two.
In subsequent backing with CSBR type latex containing 100 parts alumina trihydrate using a 7 ounce/square yard jute secondary backing, improved overall latexing performance was obtained with carpet B even though it had a heavier weight of batting material to be penetrated than carpet C, thus demonstrating the effectiveness of penetration and adhesion of the latex when our novel backing is used.
Subsequent Steiner tunnel testing of the three carpets produced consistently lower flame spread ratings for carpet B than for the other two carpets.
EXAMPLE 2
Our next test involved a carpet style that tends to be critical for pile and back burning.
The following twist set shags were prepared using 2.25/2 c.c., 4.2Z/4.5S woolen-spun yarn made from stock-dyed 15 D/F × 4 inch acrylic fiber:
A. a 36 ounce/square yard, 1-3/4 inch pile shag was tufted using spunbonded polypropylene primary backing (approximately 3.0 to 4.5 ounces/square yard).
B. a similar carpet was tufted using a woven polypropylene (approximately 3.0 to 4.5 ounces/square yard).
C. a carpet similar to B was tufted using a woven polypropylene backing into which was needle punched about 2 to 3 ounces/square yard of 3 D/F nylon staple.
D. a similar carpet was tufted using a woven polypropylene backing into which approximately 3 to 4.5 ounces/square yard of 8 D/F × 2 inch dull Verel modacrylic fiber was needle punched.
E. a similar carpet was tufted into which a 50 percent polyvinyl chloride/50 percent dull Verel modacrylic blend was substituted for 100 percent dull Verel modacrylic fiber.
Each carpet was cut in two equal sections. One section was latexed with a relatively non-fire resistant product (such as carboxylated SBR containing calcium carbonate, etc.). The other was latexed with a relatively low-grade fire-resistant product (such as a CSBR type containing 150 parts of alumina trihydrate and other necessary components). Upon subsequent tablet testing (ASTM D 2859) of these carpets (40 burns each), with and without the aforementioned washing test (AATCC Method 124-1964), it was observed that carpets D and E produced consistently better resistance to back burning than the others. All the carpets experienced various amounts of pile burning. When a 55 percent acrylic/45 percent polyvinyl chloride yarn was substituted for the 100 percent acrylic, a highly significant reduction in pile burning occurred. Thus, this test demonstrated that when our novel primary backing fabrics are used in combination with proper selection of pile yarn fabrics (and, of course, proper dyeing and fishing procedures), a highly significant improvement in both back burning and pile burning can be obtained even in certain critical styles. As the carpet pile density (measured in ounces/cubic yard) increases, the danger of pile burning decreases. The need for resistance to back burning exists in varying degrees in practically all carpet styles.
EXAMPLE 3
A comparative flammability test was made using our novel primary backing and a spunbonded polypropylene backing of prior art in the following piece-dyed shag carpet construction:
Fiber - 15 denier/filament × 6 inch staple length polyester
Yarn - 2.25/2, 4S/3Z
Weight - 31 ounces
Pile Height - 1-3/4 inches (as tufted)
Latex - CSBR with 325 parts of alumina trihydrate
Methanamine pill test results (ASTM D2859 or DOC FF 1-70) and an analysis of the burned areas were as follows:
Woven Polypropylene with 2.0 oz/yd 2 of 8 D/F × 3" Dull VEREL Modacrylic Fiber Spunbonded Polypropylene of Prior ____________________________________________________________ ______________ Art 1. Specimens Burned 40 40 2. Number of Failures 0 4 3. Statistical Analysis 40 Passing Specimens 36 Passing Specimens 36 Passing Plus 4 Failing Specimens Average Burned Area/ 1.54 Square Inches 1.90 Square Inches 2.56 Square Inches Specimen Standard Deviation 0.242 Square Inches 0.745 Square Inches 2.220 Square Inches Variance 0.0586 0.555 4.928 ____________________________________________________________ ______________
Using the F-test at the 5 percent level, the variance of the burned areas of the novel backing was found to be significantly less than that of the prior art backing. In addition, the average burned area/specimen was smaller for our novel backing than the prior art backing.
Although the invention has been described in considerable detail with particular reference to certain preferred embodiments thereof, variations and modifications may be effected within the spirit and scope of the invention.
The novel primary backings of this invention exhibit unexpected flame-retarding characteristics for such low levels of self-extinguishing flame-resistant fibers. Preferred self-extinguishing flame-resistant fibers useful in the practice of our invention are modacrylic fibers such as DYNEL (copolymer of vinylidene chloride and acrylonitrile) and VEREL (copolymer of vinylidene chloride and acrylonitrile with about 15% by weight of N-isopropylacrylamide mixed therein) and polyvinyl chloride fibers. However, it is to be understood that other fibers having self-extinguishing flame-resistant properties and which when made into a web-like structure and attached to a foundation fabric will not unduly interfere with tufting, latex application and finishing operations on the finished carpet or the like.
Prior studies have shown that about 20 to 45 percent by weight of flame-retarding fiber must be used in blends with various carpet fibers to prevent burning of the pile in certain carpet styles such as twist set shags, friezes, etc. Thus a 30 ounce/square yard shag would contain 6 to 13.5 ounces/square yard of said fire-resistant fiber(s) in the pile yarn and a 45 ounce/square yard twist set shag would contain about 9 to 20.25 ounces/square yard.
The textile foundation fabric of this invention comprises a conventional primary carpet backing having attached to one surface thereof a web-like structure comprising self-extinguishing flame-resistant fibrous materials, the web-like structure weighing from about 1 to 10 ounces/square yard. The carpets prepared using the foundation fabric of this invention may be tufted in the conventional manner. When tufted the face yarn of the carpet will extend from and through the backing and through the web-like structure so that the web-like structure is located between the free or face surface of the face yarns and the primary backing thus forming in effect a fibrous barrier between the free ends of the tufts in the carpet and the primary backing material. It is not known why only 1 to 10 ounces/square yard of the fire-resistant fibrous web-like material is sufficient to prevent back burning even when relatively non-fire resistant or relatively low-grade fire-resistant latex is used, such as carboxylated SBR latex (CSBR), CSBR with only 150 parts alumina trihydrate, relatively low viscosity pre-dry latex (such as Gafcote R-367-N modified to contain only 100 parts alumina trihydrate).
Latex penetration into carpet backing structures is facilitated by this invention. Prior art backings such as spunbonded polypropylene and woven polypropylene into which nylon fiber has been needle punched are quite difficult to penetrate, at times producing unsatisfactory adhesion between the primary and secondary backings and other problems. Thus these prior art backings tend to have an adverse effect on the performance of fire-resistant latex with regard to both adhesion and/or fire-resistance characteristics, while our novel backing is quite compatible with fire-resistant latex systems. In fact, an advantage of our invention is compatibility with existing latex systems, particularly with polyester carpet yarns and prior art polypropylene primary backing as a foundation fabric.
Our novel backings improve the uniformity of tufted pile height by minimizing differential stitch robbing, particularly when jute and woven polypropylene foundation fabrics are used.
Modacrylic and polyvinyl chloride battings have been found to be easily needle punched as compared to other battings, such as nylon. Perhaps the lower toughness of modacrylic and polyvinyl chloride is one factor, but the reasons for this improvement are not understood. In addition, the backings of this invention are easy to penetrate in tufting and cause no difficulties in overheating and deflecting the needles as can be the case with nylon needle punched into woven polypropylene.
Our novel backings, by virtue of the effect of improved latex penetration and the mat-like structure, produce a pronounced internal-padding effect. Thus a contract carpet (3/16 inch pile, 30 ounces/square yard, for example) of stock-dyed polyester or nylon fiber has a fuller, more resilient feel, more uniform pile height, more uniform shearing, and better fire-resistance characteristics. Our invention provides a more rigid backing and superior total performance compared to prior art backings. The internal-padding effect also permits the carpet to be printed, if desired, without first applying a resilient foam-type secondary backing.
In piece-dyeing, the backings of this invention, particularly when dull modacrylic is used, tend to produce superior sinking characteristics in tufted carpets. This is an important performance advantage over prior art polypropylene backings (with and without needle punched nylon) which tend to be more difficult to sink. Furthermore, the use of silicone anti-foam in dyeing has far less detrimental effect from the standpoint of backing flammability when these novel backings are used compared to products of prior art. Indeed, this is surprising in view of the relatively small amount of fire-resistant fiber used. It is a major advantage to be able to use silicone-type products in appropriate amounts for piecedyeing certain carpet styles due to the superior anti-foaming performance. In addition, this invention makes non-silicone, anti-foam products more effective. There are many shag, frieze and other styles which should by dyed with non-silicone, anti-foam products.
Perhaps due to the ability to absorb water and/or other reasons, our novel backings, particularly with modacrylic fiber, have better anti-static properties than prior art backings that utilize needle punched nylon, particularly at 30 to 50 percent RH. Again, possibly due to water absorption, improved penetration and/or other reasons, better continuous dyeing is obtained with the backing of this invention than when spunbonded polypropylene and woven polypropylene with needle punched nylon are used.
When washed as prescribed in AATCC Method 124-1964 or as amended in order to test the permanence of the latex structure containing alumina trihydrate and/or other compounds, our novel backings demonstrate a remarkable ability to minimize damage to said latex structure. This is reflected in the tablet test results when the back burning characteristics of washed carpets (such as twist set shags, plushes, etc.) are observed in a comparison between our novel primary backings and the backings of prior art.
One embodiment of our invention consists of a foundation fabric, like jute, spunbonded polypropylene (such as Typar) or woven polypropylene (such as Polybac) into which batting-like or mat-like structures made of modacrylic and/or polyvinyl chloride fibers have been needle punched. In preferred embodiments, the batting-like structure weighs approximately 1 to 6 ounces/square yard; but, if desired, weights as high as 10 ounces/square yard can be used. Even at weights in the 6 to 10 ounce/square yard range, excellent needle punching and subsequent tufting can be obtained. Our novel backing can be used for a variety of carpets, including those which are piece-dyed, continuous dyed, stock-dyed or printed.
Alternatively, the aforementioned fibers can be attached to the foundation fabric by other means, such as bonding and curing the materials in a compressed state.
In preferred embodiments of our invention, the aforementioned modacrylic and polyvinyl chloride fibers would range from 1 to 20 D/F in staple lengths of about 1 to 4 inches. Also the fibers may have incorporated therein at least 0.5 percent by weight of antimony oxide.
It is recognized that for various practical reasons -- such as inventory, economics, operational characteristics and mechanical settings of the nonwoven equipment for producing the battings, etc. -- there could be a strong need to work-off various fibers by blending with the modacrylic and polyvinyl chloride fibers of our invention. Such practice is discouraged because it tends to reduce the flame-resistance of the novel carpet backing. However, if such blending procedure is employed, the additional fiber should not exceed roughly 25 percent of the total batting weight with at least 75 percent being composed of self-extinguishing flame-resistant fibers. In no case should there be less than about 1 ounce/square yard of self-extinguishing flame-resistant fiber used in such blends.
For a better understanding of this invention, reference is made to the following examples:
EXAMPLE 1
The following contract carpets were prepared using 2.7/3 c.c., 4.75Z/3S yarns made from 15 D/F x 6 inch poly(ethylene terephthalate) polyester on the worsted system:
A. a 30 ounce/square yard, 1/4 inch pile carpet was tufted using a woven polypropylene primary. Said primary weighed about 3.0 to 4.5 ounces/square yard.
B. a similar carpet was tufted using woven polypropylene foundation fabric into which about 4 ounces/square yard of 3 D/F dull Verel CA modacrylic fiber was needle punched.
C. a carpet similar to A was tufted using a woven polypropylene fabric into which was needle punched about 2 ounces/square yard of approximately 3 D/F nylon staple fiber.
Less needle deflection and needle heating occurred in tufting carpet B than tufting carpet C even though carpet B had a greater total material weight to be penetrated by the needles. Carpet B had better tuft uniformity than A or C. The three carpets were piece-dyed honey beige using silicone antifoam. Carpet B wet-out and sank more easily than the other two.
In subsequent backing with CSBR type latex containing 100 parts alumina trihydrate using a 7 ounce/square yard jute secondary backing, improved overall latexing performance was obtained with carpet B even though it had a heavier weight of batting material to be penetrated than carpet C, thus demonstrating the effectiveness of penetration and adhesion of the latex when our novel backing is used.
Subsequent Steiner tunnel testing of the three carpets produced consistently lower flame spread ratings for carpet B than for the other two carpets.
EXAMPLE 2
Our next test involved a carpet style that tends to be critical for pile and back burning.
The following twist set shags were prepared using 2.25/2 c.c., 4.2Z/4.5S woolen-spun yarn made from stock-dyed 15 D/F × 4 inch acrylic fiber:
A. a 36 ounce/square yard, 1-3/4 inch pile shag was tufted using spunbonded polypropylene primary backing (approximately 3.0 to 4.5 ounces/square yard).
B. a similar carpet was tufted using a woven polypropylene (approximately 3.0 to 4.5 ounces/square yard).
C. a carpet similar to B was tufted using a woven polypropylene backing into which was needle punched about 2 to 3 ounces/square yard of 3 D/F nylon staple.
D. a similar carpet was tufted using a woven polypropylene backing into which approximately 3 to 4.5 ounces/square yard of 8 D/F × 2 inch dull Verel modacrylic fiber was needle punched.
E. a similar carpet was tufted into which a 50 percent polyvinyl chloride/50 percent dull Verel modacrylic blend was substituted for 100 percent dull Verel modacrylic fiber.
Each carpet was cut in two equal sections. One section was latexed with a relatively non-fire resistant product (such as carboxylated SBR containing calcium carbonate, etc.). The other was latexed with a relatively low-grade fire-resistant product (such as a CSBR type containing 150 parts of alumina trihydrate and other necessary components). Upon subsequent tablet testing (ASTM D 2859) of these carpets (40 burns each), with and without the aforementioned washing test (AATCC Method 124-1964), it was observed that carpets D and E produced consistently better resistance to back burning than the others. All the carpets experienced various amounts of pile burning. When a 55 percent acrylic/45 percent polyvinyl chloride yarn was substituted for the 100 percent acrylic, a highly significant reduction in pile burning occurred. Thus, this test demonstrated that when our novel primary backing fabrics are used in combination with proper selection of pile yarn fabrics (and, of course, proper dyeing and fishing procedures), a highly significant improvement in both back burning and pile burning can be obtained even in certain critical styles. As the carpet pile density (measured in ounces/cubic yard) increases, the danger of pile burning decreases. The need for resistance to back burning exists in varying degrees in practically all carpet styles.
EXAMPLE 3
A comparative flammability test was made using our novel primary backing and a spunbonded polypropylene backing of prior art in the following piece-dyed shag carpet construction:
Fiber - 15 denier/filament × 6 inch staple length polyester
Yarn - 2.25/2, 4S/3Z
Weight - 31 ounces
Pile Height - 1-3/4 inches (as tufted)
Latex - CSBR with 325 parts of alumina trihydrate
Methanamine pill test results (ASTM D2859 or DOC FF 1-70) and an analysis of the burned areas were as follows:
Woven Polypropylene with 2.0 oz/yd 2 of 8 D/F × 3" Dull VEREL Modacrylic Fiber Spunbonded Polypropylene of Prior ____________________________________________________________ ______________ Art 1. Specimens Burned 40 40 2. Number of Failures 0 4 3. Statistical Analysis 40 Passing Specimens 36 Passing Specimens 36 Passing Plus 4 Failing Specimens Average Burned Area/ 1.54 Square Inches 1.90 Square Inches 2.56 Square Inches Specimen Standard Deviation 0.242 Square Inches 0.745 Square Inches 2.220 Square Inches Variance 0.0586 0.555 4.928 ____________________________________________________________ ______________
Using the F-test at the 5 percent level, the variance of the burned areas of the novel backing was found to be significantly less than that of the prior art backing. In addition, the average burned area/specimen was smaller for our novel backing than the prior art backing.
Although the invention has been described in considerable detail with particular reference to certain preferred embodiments thereof, variations and modifications may be effected within the spirit and scope of the invention.