阅读说明：本技术 低渗透性和高强度织造织物及其制造方法 (Low permeability and high strength woven fabrics and methods of making same ) 是由 尼尔·亨特 于 2018-04-26 设计创作，主要内容包括：本发明题为“低渗透性和高强度织造织物及其制造方法”。本发明提供了一种用于产生织造织物的方法,该方法包括沿经向和纬向编织纤维以形成具有顶部表面和底部表面的织物,其中经向纤维和纬向纤维各自包括一根或多根合成聚合物长丝,该一根或多根合成聚合物长丝具有基本上均匀的横截面组分。然后在熔合步骤期间添加或在织物产生过程的先前步骤中添加并被长丝保留的热传递液体或蒸气存在的情况下,将织物的顶部表面和/或底部表面上的纤维中的长丝的至少一部分熔合在一起。该熔合步骤产生经处理的织物,该经处理的织物在经向和纬向上均具有1000N或更大的拉伸强度并且在不存在任何涂层的情况下具有3l/dm<Sup>2</Sup>/min或更低的静态透气性(SAP)。(The invention provides a low permeability and high strength woven fabric and a method of making the same. The present invention provides a method for producing a woven fabric comprising weaving fibers in warp and weft directions to form a fabric having a top surface and a bottom surface, wherein the warp and weft fibers each comprise one or more synthetic polymer filaments having a substantially uniform cross-sectional composition. Heat transfer liquid or steam added during the fusing step or added in a previous step of the fabric production process and retained by the filamentsAt least a portion of the filaments in the fibers on the top and/or bottom surfaces of the fabric are fused together in the presence of gas. This fusing step results in a treated fabric having a tensile strength of 1000N or greater in both the warp and weft directions and 3l/dm in the absence of any coating 2 Static Air Permeability (SAP) of/min or less.)

1. A method for producing a woven fabric, the method comprising:

(a) weaving fibers in warp and weft directions to form a fabric having a top surface and a bottom surface, wherein the warp fibers and the weft fibers each comprise one or more synthetic polymer filaments having a substantially uniform cross-sectional composition;

(b) fusing together at least a portion of the filaments in the fibers on the top surface of the fabric or at least a portion of the filaments in the fibers on the bottom surface of the fabric, wherein the filaments are fused together in the presence of a heat transfer liquid or vapor added during the fusing step or added in a previous step of the fabric production process and retained by the filaments, and wherein the fusing step produces a fiber with a tensile strength of 1000N or greater in both the warp and weft directions and 3l/dm without any coating²A Static Air Permeability (SAP) of the treated fabric of/min or less.

2. The method of claim 1, wherein the fusing is performed by treating the woven fabric at a temperature and/or pressure sufficient to permanently change cross-sectional dimensions and fuse at least a portion of the filaments in the fibers on the top surface of the fabric and at least a portion of the filaments in the fibers on the bottom surface of the fabric.

3. A method for producing a woven fabric, the method comprising:

(a) weaving fibers in warp and weft directions to form a fabric having a top surface and a bottom surface, wherein the warp fibers and the weft fibers each comprise one or more synthetic polymer filaments having a substantially uniform cross-sectional composition;

(b) calendering the fabric in the presence of heat and heat transfer liquid or vapor added during the calendering step or added in a previous step of the fabric production process and retained by the fabric, wherein the calendering step permanently alters the cross-section of at least a portion of the filaments in the fibers on the top surface of the fabric or at least a portion of the filaments in the fibers on the bottom surface of the fabric to produce a fabric having a tensile strength of 1000N or greater in both the warp and weft directions and 3l/dm without any coating²A Static Air Permeability (SAP) of the treated fabric of/min or less.

4. The method of claim 2 or claim 3, wherein the temperature in step (b) is reduced compared to the temperature required to permanently change the cross-sectional dimension and fuse at least a portion of the filaments in the absence of a heat transfer liquid or vapor.

5. The process of any one of claims 2 to 4, wherein the temperature in step (b) is below the dry softening point of the synthetic polymer filaments.

6. The method of any one of claims 2 to 5, wherein the pressure in step (b) is reduced compared to the pressure required to permanently change the cross-sectional dimension and fuse at least a portion of the filaments in the absence of a heat transfer liquid or vapor.

7. The method of any of claims 2 to 6, wherein the permanently altered cross-section results in at least a portion of the filaments having an aspect ratio of about 1.2: 1 to about 10: 1.

8. The method of any one of claims 2 to 7, wherein the treating comprises hot roll calendering the woven fabric.

9. The process of claim 8, wherein the hot roll calendering is conducted at a fabric speed of from about 5 to about 80m/min, preferably from about 10 to about 70m/min, and more preferably from about 12 to about 50 m/min.

10. The method of any preceding claim, wherein the fabric has a root mean square surface (RMS) surface roughness in the range of from about 2 to about 70 μ ι η, preferably from about 5 to about 60 μ ι η.

11. The method of any preceding claim, wherein the treated fabric exhibits a slip resistance of 150N or greater in both the warp and weft directions when the fabric is unaged.

12. A method according to any preceding claim, wherein the heat transfer liquid or vapour comprises water.

13. The method of any preceding claim, the amount of heat transfer liquid or vapor added prior to fusing being in the range of from about 5 wt.% to about 30 wt.%, such as from about 10 wt.% to about 20 wt.%, such as from about 12 wt.% to about 18 wt.%, by weight of the dry fabric.

14. The method of any preceding claim, wherein the presence of the heat transfer liquid or vapor results from weaving, washing, or dyeing with a water jet loom.

15. The method of any preceding claim, wherein the fibers have a linear density in the range of about 150 to about 1000 decitex, preferably in the range of about 150 to about 750 decitex.

16. The method of any preceding claim, wherein the filaments have a linear density in the range of about 1 dtex to about 25 dtex.

17. The method of any preceding claim, wherein the fibers are formed from a synthetic polymer selected from polyamides, polyesters, polyolefins and blends or copolymers thereof.

18. A method according to any preceding claim wherein one of both the warp and weft fibres comprises one or more filaments formed from a single synthetic polymer or blend, for example, preferably wherein all of the warp and weft fibres comprise filaments formed from a single polymer or blend.

19. The method of any preceding claim, further comprising applying a coating to the treated fabric to further reduce its electrostatic air permeability (SAP).

20. A fabric produced by the method of any one of claims 1 to 19.

21. An article made from the fabric of claim 20.

22. The article of claim 21, selected from the group consisting of an airbag, a canvas, an inflatable slide, a tent, a duct, a garment, a filter, a cover, and a print medium.

23. An airbag formed from the fabric of claim 20.

24. A method for increasing the processing speed at which hot roll calendering of a woven fabric is performed to obtain a selected air permeability value, wherein the fabric has a tensile strength in the warp or weft direction of ≧ 1000N, the method comprising the step of hot roll calendering the fabric in the presence of an added heat transfer liquid or vapor, wherein at least one physical property of the fabric other than air permeability is improved as compared to the physical property of the same fabric calendered to obtain the selected air permeability value in the absence of the added heat transfer liquid or vapor.

25. The method of claim 24, wherein the physical property improved by the hot roll calendering the fabric in the presence of the added heat transfer liquid or vapor comprises at least one of: fabric tenacity, elongation at break, fabric toughness, tear strength, and slip resistance.

26. The method of claim 24 or claim 25, wherein the heat transfer liquid comprises water or the heat transfer vapor comprises steam.

27. The method of any of claims 24 to 26, wherein the temperature of the hot roll is reduced compared to a temperature of hot roll calendering in the absence of the heat transfer liquid or vapor.

28. The process of any one of claims 24 to 27, wherein the process pressure is reduced compared to the process pressure of hot roll calendering in the absence of the heat transfer liquid or vapor.

29. The method of any of claims 24-28, wherein the resulting fabric has a tensile strength of at least 85% of the tensile strength of the fabric prior to the hot roll calendering step.

Technical Field

The present invention relates to woven fabrics of synthetic fiber yarns and methods for producing and using such fabrics to produce products such as, but not limited to, airbags, canvases, inflatable slides, tents, pipes, garments, filters, coverings, and print media.

Background

Fabrics and textiles with high tensile strength have many industrial applications. Many industrial applications require fabrics to meet a number of requirements in order to be useful. These requirements may include tensile strength, breathability, surface finish, stiffness, and packability. Examples of such applications include airbags, canvases, inflatable slides, tents, ducts, coverings, and print media.

Inflatable airbags are a key component of vehicle safety systems. As used herein, "airbag" refers to an inflatable passive safety restraint device for automobiles and many other forms of transportation, including military and aerospace applications. Airbags are one form of inflatable passive safety restraint and are now the standard configuration for automobiles. In recent years, the number of airbags and the coverage area of these airbags in various types of vehicle compartments have increased. The multiple airbag configurations in use include airbags for front seat areas, for side impact protection, for rear seat applications, for headliner area inflatable curtains, and for inflating seat belts or pedestrian airbags.

In addition, as automobiles tend to turn to smaller and lighter vehicles, space available for mandatory safety items such as airbags sometimes becomes smaller, and some airbags need to be larger in size to meet the evolving standards for automotive safety. This leads to the problem that some airbag modules need to be smaller and some airbags need to be larger. Methods of packaging air bags at higher pressures and/or temperatures have been developed. While such methods result in improved packability of the airbag within the module, they also tend to be expensive and increase the complexity of the airbag module manufacturing process.

To meet the requirements for effective inflation, airbag fabrics must meet certain tensile strength requirements and have the ability to resist the passage of air, which is defined by a measure of breathability. Therefore, woven nylon or polyester airbags are desired to have very low porosity and correspondingly low air permeability. While fabric properties such as linear density, twist multiplier, weave construction, and thickness and weight of the yarn all affect breathability, it is often necessary to add coatings or additional layers to the airbag fabric to meet industry standards.

Traditionally, air and liquid impermeable structures have been achieved using various forms of coated fabrics produced by processes such as gravure coating, immersion, knife-roll coating, curtain coating, knife coating, reverse roll, rotary screen, transfer, extrusion, hot melt, lamination, impregnation, and metering bars. All of these approaches add significant cost to the base fabric.

Polyester and polyamide fabrics with various coatings to reduce permeability are known. U.S. patent No.5,897,929 describes a polyester or polyamide fabric coated with a pore barrier layer of polyamide material. U.S. patent No.5,110,666 describes a fabric substrate that is typically coated with a polycarbonate-polyether polyurethane that provides certain permeability, flexibility, toughness and heat resistance benefits. U.S. patent No.5,076,975 describes a molding operation for forming an elastomer coated fabric having a defined shape. U.S. patent No.5,763,330 describes a method of extrusion coating polyethylene resin onto nylon fabric. Woven fabrics from which airbags are traditionally made may also be coated with elastomeric materials, particularly silicone rubber, to manage the air permeability of the fabric.

However, not only is the coating process slow and laborious, but the coating itself is also expensive, thus making these airbags very expensive. In addition, the coatings can interfere with the foldability of these fabrics, which is an essential feature of airbags.

Therefore, alternatives to coatings for airbag fabrics have been sought. For example, attempts have been made in the past to form low permeability structures that require reduced amounts or coatings that do not rely on individual yarn shrinkage to produce the necessary dense structure. For example, U.S. Pat. Nos. 4,921,735 and 5,540,965 teach shrinking and then heat setting the fabric to improve air impermeability. U.S. patent No. re38,769E 1 also discusses compressing the fabric with the aid of an extensible belt and heated rollers, but then allowing the fabric to recoil to improve the foldability of the fabric without adversely affecting air permeability.

U.S. patent No.5,073,418, canadian patent No.2014249C, and chinese patent No. cn101033569b describe calendering the airbag fabric to below its softening temperature on both sides, resulting in a non-permanent, low permeability structure due to the high points of the fabric being depressed. The present invention discloses that the decrease in permeability observed due to rewetting is not permanent for nylon 6, 6 fabrics.

Published U.S. patent application No.2013/0035014 discloses a fabric that maintains low air permeability after the fabric is laundered. The high-density fabric includes textured synthetic fibers having a fineness of 28 dtex or less and an overall cover factor in the range of 1700 to 2200. The disclosed uses of the fabric include side panels for down jackets, futons (i.e., japanese bedding), and sleeping bags.

WO 2015/130882 discloses a woven fabric for an airbag comprising a base yarn and a secondary yarn, wherein the secondary yarn is interwoven into the base yarn, and wherein the melting point of the secondary yarn is lower than the melting point of the base yarn. The invention also discloses a method of manufacturing a base yarn and a secondary yarn, wherein the secondary yarn is interwoven into the base yarn, and wherein the melting point of the secondary yarn is lower than the melting point of the base yarn.

U.S. patent No.8,733,788B2 discloses a woven fabric that is pretreated with an additive and then activated and compressed to form a lower permeability fabric. This compression is disclosed as being specific to the yarn bundle in which the additives are present to bind the yarn in the compressed configuration.

WO2017/079499 (the entire content of which is incorporated herein by reference) discloses a fabric suitable for use in products such as, but not limited to, airbags, the fabric comprising: by edgeSynthetic fiber-formed yarns woven in the warp and weft directions to form top and bottom surfaces; wherein at least a portion of the yarns on the top surface or at least a portion of the yarns on the bottom surface have fibers that are fused together so as to have a permanent habit change cross-section; wherein the fabric has a Static Air Permeability (SAP) of 3l/dm when the fabric is not aged²(ii)/min or less; and wherein the fabric has a tensile strength of 1000N or greater in both the warp and weft directions when the fabric is unaged.

The present disclosure provides an improved method of making high strength foldable fabrics with permanently altered and fused surface filaments that require a reduced amount of coating or no coating at all and still meet key performance criteria required for uses such as, but not limited to, airbags, such as permanently low air permeability and high tensile strength.

Disclosure of Invention

The present disclosure relates to a method for increasing the processing speed and productivity of a process for producing an uncoated woven fabric comprising synthetic fiber yarns with permanently low permeability and articles comprising such fabrics. In particular, it has been surprisingly found that the inclusion of a heat transfer liquid or vapor during the treatment of the fabric to permanently alter the cross-section and fuse at least a portion of the filaments in the fibers on the top or bottom surface of the fabric results in a faster process to produce an uncoated woven fabric with permanently low permeability.

Accordingly, one aspect of the present disclosure is directed to a method for producing a woven fabric having permanently low permeability, the method comprising:

(a) weaving fibers in warp and weft directions to form a fabric having a top surface and a bottom surface, wherein the warp and weft fibers each comprise one or more synthetic polymer filaments having a substantially uniform cross-sectional composition;

(b) fusing together at least a portion of the filaments in the fibers on the top surface of the fabric or at least a portion of the filaments in the fibers on the bottom surface of the fabric, wherein the filaments are fused together in the presence of a heat transfer liquid or vapor added during the fusing step or added in a previous step of the fabric production process and retained by the filaments, and wherein the fusing step produces a treated fabric having a tensile strength of 1000N or greater in both the warp and weft directions and a Static Air Permeability (SAP) of 3l/dm2/min or less without any coating.

Another aspect of the present disclosure relates to a method for producing a woven fabric having permanently low permeability, the method comprising:

(a) weaving fibers in warp and weft directions to form a fabric having a top surface and a bottom surface, wherein the warp and weft fibers each comprise one or more synthetic polymer filaments having a substantially uniform cross-sectional composition;

(b) calendering the fabric in the presence of heat and heat transfer liquid or vapor added during the calendering step or added in a previous step of the fabric production process and retained by the fabric, wherein the calendering step permanently alters the cross-section of at least a portion of the filaments in the fibers on the top surface of the fabric or at least a portion of the filaments in the fibers on the bottom surface of the fabric to produce a fabric having a tensile strength of 1000N or greater in both the warp and fill directions and 3l/dm without any coating²A Static Air Permeability (SAP) of the treated fabric of/min or less.

In one non-limiting embodiment, the presence of the heat transfer liquid or vapor is generated by entrainment of residual moisture introduced by weaving, washing or dyeing with a water jet loom.

In one non-limiting embodiment, fusing is performed by treating the woven fibers at a temperature and/or pressure sufficient to fuse and permanently alter the cross-sectional dimensions of at least a portion of the filaments in the fibers. In one non-limiting embodiment, the treatment temperature and/or pressure is reduced compared to the temperature and/or pressure required to fuse and permanently change the cross-sectional dimensions of the portion of the filament in the absence of a heat transfer liquid or vapor. In one non-limiting embodiment, the treatment is performed at an increased rate compared to the treatment rate required to fuse and permanently change the cross-sectional dimensions of the portion of the filament at the same temperature and pressure but in the absence of a heat transfer liquid or vapor.

Another aspect of the present disclosure relates to a fabric produced according to the method described herein.

The fabric produced according to the method of the present invention has low dynamic air permeability. In one non-limiting embodiment, a fabric produced according to the method exhibits a Dynamic Air Permeability (DAP) of 500mm/s or less when the fabric is not aged.

One aspect of the present disclosure relates to an article made from a fabric. Non-limiting examples of such articles include airbags, canvases, inflatable slides, tents, tubes, garments, filters, covers, and print media.

Yet another aspect of the present disclosure relates to a method for accelerating the speed of a process performing hot roll calendering of a woven fabric to achieve a selected air permeability value, wherein the fabric has a tensile strength in the warp or weft direction of ≧ 1000N, the method comprising the step of hot roll calendering the fabric in the presence of an added heat transfer liquid or vapor, wherein at least one physical property of the fabric other than air permeability is improved as compared to the physical property of the same fabric calendered to achieve the selected air permeability value in the absence of the added heat transfer liquid or vapor.

In one non-limiting embodiment, the physical properties improved by hot roll calendering the fabric in the presence of added heat transfer liquid or vapor include at least one of: fabric tenacity, elongation at break, fabric toughness, tear strength, and slip resistance.

Drawings

Fig. 1 is a line graph of SAP versus High Temperature and High Pressure (HTHP) processing speed, illustrating the problem of SAP increasing with increasing processing speed when processing nylon 6, 6 fabric of example 1 (comparative) in the absence of a heat transfer medium.

Fig. 2 is a line graph of SAP versus HTHP processing speed, illustrating the problem of SAP increasing with increasing processing speed when processing the PET fabric of example 2 (comparative) in the absence of a heat transfer medium.

Fig. 3A and 3B are graphs of SAP (fig. 3A) and DAP (fig. 3B) versus HTHP processing speed for processing the nylon 6, 6 fabric of example 3 in the presence and absence of a heat transfer medium.

Fig. 4A to 4F are SEM images of the fabric described in example 3 after dry and wet HTHP treatment. Fig. 4A and 4B show the surface structure of a fabric treated with dry HTHP at a treatment speed of 5m/min at 2 different magnifications. Fig. 4C and 4D show the surface structure of the fabric treated with dry HTHP at a treatment speed of 30m/min at 2 different magnifications. Fig. 4E and 4F show the surface structures of wet HTHP treated fabrics at a treatment speed of 30m/min at 2 different magnifications.

Fig. 5A and 5B are graphs of SAP (fig. 5A) and DAP (fig. 5B) versus HTHP processing speed for treating the PET fabric of example 4 in the presence and absence of a heat transfer liquid or vapor.

Fig. 6A to 6F are SEM images of the fabric described in example 4 after dry and wet HTHP treatment. Fig. 6A and 6B show the surface structure of a fabric treated with dry HTHP at a treatment speed of 5m/min at 2 different magnifications. Fig. 6C and 6D show the surface structure of the fabric treated with dry HTHP at a treatment speed of 30m/min at 2 different magnifications. Fig. 6E and 6F show the surface structures of wet HTHP treated fabrics at a treatment speed of 30m/min at 2 different magnifications.

Fig. 7A to 7D are SEM images showing the surface structure of the fabric described in example 5 at 2 different magnifications after wet HTHP treatment under two different temperature and pressure conditions.

Figure 8 is a boxplot comparing the average fabric tenacity of a range of nylon 6, 6 fabrics after dry and wet calendering as described in example 6.

Figure 9 is a boxplot comparing the average fabric break extension of a series of nylon 6, 6 fabrics after dry and wet calendering as described in example 6.

Figure 10 is a boxplot comparing the average fabric tenacity or work to break of a series of nylon 6, 6 fabrics after dry and wet calendering as described in example 6.

Figure 11 is a boxplot comparing the average fabric slippage resistance strength of a series of nylon 6, 6 fabrics after dry and wet calendering as described in example 6.

Figure 12 is a boxplot comparing the average fabric tear strength of a series of nylon 6, 6 fabrics after dry and wet calendering as described in example 6.

Figure 13 is a boxplot comparing the average fabric static air permeability of a series of nylon 6, 6 fabrics after dry and wet calendering as described in example 6.

Figure 14 is a boxplot comparing the average fabric dynamic air permeability of a series of nylon 6, 6 fabrics after dry and wet calendering as described in example 6.

Detailed Description

The present disclosure relates to a method of producing a woven fabric from synthetic fibers, wherein the fabric in an uncoated form has permanently reduced air permeability and porosity as compared to a conventional uncoated fabric formed from the same synthetic fibers in the same fabric construction.

The method of the present invention includes weaving synthetic fibers in warp and weft directions to form a woven fabric having a top surface and a bottom surface, wherein the warp and weft fibers each comprise one or more synthetic polymer filaments having a substantially uniform cross-sectional composition. At least a portion of the filaments in the fibers on the top surface of the fabric and/or at least a portion of the filaments in the fibers on the bottom surface of the fabric are then fused together in the presence of a heat transfer liquid or vapor added during the fusing step or added in a previous step of the fabric production process and retained by the filaments. The fusing step produces a treated fabric having a tensile strength of 1000N or greater in both the warp and weft directions and 3l/dm in the absence of any coating²Static Air Permeability (SAP) of/min or less.

In one non-limiting embodiment, the fusing step results in at least a portion of the filaments on the top surface and/or at least a portion of the filaments on the bottom surface of the treated fabric having a permanently altered cross-section. In another non-limiting embodiment, the fusing step results in a majority (at least half) of the filaments on the top surface of the treated fabric or a majority of the filaments on the bottom surface of the treated fabric having a permanently altered cross-section. In another non-limiting embodiment, the fusing step results in a majority (at least half) of the filaments on the top surface of the treated fabric and a majority of the filaments on the bottom surface of the treated fabric having permanently altered cross-sections and being fused together.

The combination of the planarization and fusing of the surface filaments results in a fabric having a reduced surface roughness. In one non-limiting embodiment of the present disclosure, the treated fabric produced by the methods described herein has a Root Mean Square (RMS) surface roughness in the range of about 2 to about 70 μm, preferably about 5 to about 60 μm.

In one non-limiting embodiment of the present disclosure, the treated fabric has a Dynamic Air Permeability (DAP) of 500mm/s or less when the fabric is not aged. All DAP values mentioned herein were measured according to a modified version of ISO 9237 described below. All SAP values mentioned herein were measured according to the modified version of ASTM D6476 described below.

As used herein, the term "permanently altered cross-section" refers to a modified or compressed version of the cross-section of the filament of at least a portion of the filaments used in the untreated fabric. The filaments within the fibers of the untreated fabric may have any cross-section known in the art, including but not limited to round, multi-lobal, tri-lobal, hexagonal, or rectangular. In one non-limiting embodiment, the filaments in the fibers of the untreated fabric have a circular cross-section. In one non-limiting embodiment, the permanently altered cross-section results in at least a portion of the fibers being substantially flat. See fig. 4A-4F.

As used herein, the term "permanent" or "permanently" means that the altered cross-section does not return to its original shape.

As used herein, the term "High Temperature and High Pressure (HTHP)" treatment refers to treating a fabric at a selected temperature and/or a selected pressure such that at least a portion of the filaments on the top surface or at least a portion of the filaments on the bottom surface of the treated woven fabric have a permanently altered cross-section and are fused together such that the air permeability and porosity of the treated fabric is reduced as compared to a woven fabric formed from the same synthetic fibers but without the heat treatment. It was previously believed that HTHP treatment of fabrics (e.g., by calendering the fabric at an elevated temperature near the melting point of the yarns) would result in thermally induced mechanical degradation of the fabric, a reduction in fabric stretch and tear strength, resulting in poor dimensional stability and a significant increase in stiffness. For example, previous attempts to calender weave fabrics with high temperatures and pressures can result in paper-like rigid products and do not produce the desired fabric properties for applications such as airbag fabrics.

The inventors have surprisingly found that HTHP treatment in the presence of a heat transfer liquid or vapor, preferably in combination with improved HTHP treatment conditions, such as reduced temperature and/or pressure compared to the temperature and/or pressure sufficient to permanently change the cross-section and fuse at least a portion of the filaments in the fiber in the absence of a heat transfer liquid or vapor, can improve heat transfer, which is sufficient to change the cross-section of the surface filaments and fuse these filaments to obtain permanently low permeability at increased treatment speeds, but without damaging the preferred structure in a manner that reduces the strength of the fabric. Using the methods of the present disclosure, the previously disclosed low permeability fabrics can be produced at significantly higher processing speeds.

Additionally, performing the HTHP treatment in the presence of the heat transfer liquid or vapor results in an improvement in the physical properties of the fabric, including at least one of: fabric tenacity, elongation at break, fabric toughness, tear strength, and slip resistance strength.

The term "heat transfer liquid or vapor" refers to a liquid or vapor that is included in the fibers or filaments during HTHP processing and that acts as a processing promoter to increase production. In one non-limiting embodiment, the heat transfer liquid is primarily water.

As used herein, the term "unaged" refers to a treated fabric directly after being subjected to one or more steps that result in at least a portion of the filaments in the fibers on the top and/or bottom surfaces of the fabric fusing and preferably permanently deforming.

As used herein, the term "substantially uniform cross-sectional composition" as used in connection with the filaments of each of the warp and weft fibers means that the composition of the filaments (extending along the length of the filaments) measured at the centerline of the filaments is substantially the same as the composition measured at an increasing radius relative to the centerline. In one non-limiting embodiment, a majority (more than half) of the fibers used in the warp direction of the fabric are formed from one or more filaments made from a single synthetic polymer. In another non-limiting embodiment, a majority (more than half) of the fibers used in the weft direction of the fabric are formed from a single synthetic polymer. In another non-limiting embodiment, a majority of the fibers used in the warp and weft directions of the fabric are formed from one or more filaments made from a single synthetic polymer. In one non-limiting embodiment, all of the fibers used in the warp direction of the fabric are formed from one or more filaments made from a single synthetic polymer. In another non-limiting embodiment, all of the fibers used in the weft direction of the fabric are formed from one or more filaments made from a single synthetic polymer. In another non-limiting embodiment, all of the fibers used in the warp and weft directions of the fabric are formed from one or more filaments made from a single synthetic polymer.

Examples of synthetic polymers used to produce filaments and fibers for use in the present disclosure include, but are not limited to, polyamides, polyesters, polyolefins, and blends or copolymers thereof.

In one non-limiting embodiment, the linear density of the fibers used herein is in the range of about 150 to about 1000 decitex, preferably in the range of about 150 to about 750 decitex.

Suitable polyamide fibers have a linear mass density in the range of 100 to 1000 dtex, such as 200 to 950 dtex, 150 to 750 dtex, 200 to 900 dtex, 250 to 850 dtex, 300 to 850 dtex, 350 to 850 dtex, 400 to 800 dtex, and 450 to 800 dtex. Suitable polyamide fibers include those formed from: nylon 6, nylon 6, 12, nylon 7, nylon 12, nylon 4, 6, or copolymers or blends thereof. In one non-limiting embodiment of the present disclosure, the base yarn is formed from nylon 6, 6 fibers.

Suitable polyester fibers have a linear mass density in the range of 100 to 950 dtex, such as 150 to 750 dtex, 300 to 900 dtex, 300 to 850 dtex, 350 to 850 dtex, 400 to 800 dtex, 450 to 800 dtex, and 500 to 800 dtex. Suitable polyester fibers include polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene-1, 2-bis (phenoxy) ethane-4, 4' -dicarboxylate, poly (1, 4-cyclohexylene-dimethylene terephthalate), and copolymers comprising at least one of the foregoing polymeric repeat units, such as polyethylene terephthalate/isophthalate copolyester, polybutylene terephthalate/naphthalate copolyester, polybutylene terephthalate/decanedicarboxylate copolyester, or copolymers or blends thereof. In one non-limiting embodiment of the present disclosure, the base yarns are formed from PET fibers.

The fibers used in the present disclosure may also include various additives used in fiber production and processing. Suitable additives include, but are not limited to, heat stabilizers, antioxidants, light stabilizers, smoothing agents, antistatic agents, plasticizers, thickeners, pigments, flame retardants, fillers, adhesives, fixatives, softeners, or combinations thereof.

In one non-limiting embodiment, the filaments used to produce the fibers used herein have a linear density in the range of about 1 to about 25 Dtex Per Filament (DPF), such as in the range of about 2 to about 12 Dtex Per Filament (DPF).

The woven fabrics of the present disclosure may be formed from warp and weft fibers using weaving techniques known in the art. Suitable weaving techniques include, but are not limited to, plain, twill, satin, these types of modified weaves, one-piece weave (OPW) or multi-axial weaves. Suitable looms that can be used for weaving include water jet looms, air jet looms, or rapier looms. These looms may also be used with a jacquard to form an OPW structure. Suitable woven fabrics of the present disclosure may have a total basis weight in the range of 80 to 4500 grams per square meter. In certain embodiments, the total basis weight of the woven fabric may range from 100 to 4500 grams per square meter, 100 to 4000 grams per square meter, 100 to 3500 grams per square meter, 150 to 4500 grams per square meter, 150 to 4000 grams per square meter, 150 to 3500 grams per square meter, 200 to 4500 grams per square meter, 200 to 4000 grams per square meter, 200 to 3500 grams per square meter, 250 to 4500 grams per square meter, 250 to 4000 grams per square meter, 250 to 3500 grams per square meter.

In one non-limiting embodiment of the present disclosure, the untreated woven fabric has greater than 3l/dm when measured according to the test method described herein²Min, e.g. greater than 5l/dm²Min, e.g. greater than 10l/dm²Static Air Permeability (SAP)/min.

In one non-limiting embodiment of the present disclosure, the untreated woven fabric has a Dynamic Air Permeability (DAP) of greater than 500mm/s, such as greater than 750mm/s, such as greater than 1000mm/s, when measured according to the test method described herein.

In one non-limiting embodiment of the present disclosure, the untreated woven fabric has a fabric tensile strength of 1000N or greater in both the warp and weft directions when the fabric is not aged. In another non-limiting embodiment of the present disclosure, the fabric has a tensile strength of 1500N or greater in both the warp and fill directions when the fabric is unaged. In another non-limiting embodiment of the present disclosure, the fabric has a tensile strength of 2000N or greater in both the warp and weft directions when the fabric is unaged. In one non-limiting embodiment of the present disclosure, the fabric has a tensile strength of 2500N or greater in both the warp and weft directions when the fabric is unaged. In yet another non-limiting embodiment of the present disclosure, the fabric has a tensile strength of 3000N or greater in both the warp and weft directions when the fabric is unaged.

In one non-limiting embodiment, the basis weight of the fabric is from about 80 to about 500gm^-2Within the range of (1).

According to the present disclosure, after the above-described fibers are woven in the warp and weft directions to form a fabric having a top surface and a bottom surface, the resulting fabric is treated in the presence of a heat transfer medium to permanently change the cross-section and fuse at least a portion of the filaments in the fibers on the top surface of the fabric or at least a portion of the filaments in the fibers on the bottom surface of the fabric. In one non-limiting embodiment, the processing conditions that permanently alter the cross-section and fuse at least a portion of the filaments on the top surface of the fabric or at least a portion of the filaments on the bottom surface of the fabric are modified as compared to the conditions used to fuse and permanently alter the cross-section of the filaments in the absence of a heat transfer medium. In one non-limiting embodiment, the processing temperature is reduced compared to the temperature required to permanently change the cross-section and fuse at least a portion of the filaments in the fabric in the absence of a heat transfer medium. In one non-limiting embodiment, the processing pressure is reduced compared to the pressure required to permanently change the cross-section and fuse at least a portion of the filaments in the fabric in the absence of a heat transfer medium. In one non-limiting embodiment, the processing temperature and pressure are reduced compared to the temperature and pressure required to permanently change the cross-section and fuse at least a portion of the filaments in the fabric in the absence of a heat transfer medium. In one non-limiting embodiment, the fabric is treated to permanently change the cross-section and fuse at least a portion of the filaments on the top surface of the fabric and at least a portion of the filaments in the fibers on the bottom surface of the fabric. In another non-limiting embodiment, the fabric is treated to permanently change the cross-section and fuse at least a majority of the filaments on the top surface of the fabric or a majority of the filaments on the bottom surface of the fabric. In another non-limiting embodiment, the fabric is treated to permanently change the cross-section and fuse a majority of the filaments on the top surface of the fabric and a majority of the filaments on the bottom surface of the fabric.

The temperature and pressure used in the HTHP process are selected to permanently change the cross-section and fuse at least a portion of the filaments in the fabric, but not to damage the filaments and reduce the strength of the fabric. In a non-limiting embodiment, the temperature used is above the softening temperature of the fibers. In another non-limiting embodiment, the temperature is below the softening point of conventional dried polymers. In one non-limiting embodiment, the fabric formed from nylon 6, 6 fibers may be HTHP treated at a temperature in the range of from about 130 ℃ to about 240 ℃. In another non-limiting embodiment, the fabric formed from PET fibers may be HTHP treated at a temperature in the range of from about 130 ℃ to about 240 ℃. In a non-limiting embodiment, the pressure used for the HTHP treatment ranges from about 28MPa to about 115MPa, such as from about 35MPa to about 70 MPa. In the case of HTHP treatment by hot roll calendering, the pressure is calculated from the total applied force on the fabric area at the nip point of the calender. The fabric may be HTHP treated by any method known in the art that applies the temperature and pressure necessary to permanently change the cross-section and fuse at least a portion of the filaments in the fabric. In one non-limiting embodiment, the HTHP treatment comprises hot roll calendering the fabric. In the case where the HTHP treatment is achieved by hot roll calendering, the fabric speed at the nip point of the calender may be in the range of from about 5m/min to about 80m/min, such as from about 10m/min to about 70m/min, for example from about 12m/min to about 50 m/min.

In one non-limiting embodiment, the fabric is subjected to an HTHP treatment in the presence of a heat transfer medium present in an amount of from about 5 to about 30 wt%, for example from about 10 to about 20 wt%, such as from about 12 to about 18 wt%, based on the weight of the dry fabric. In non-limiting embodiments, the heat transfer liquid or vapor may be present as carried by a prior step in the fabric production process, not limited to residual liquid from a water jet loom or from a washing or scouring process or from a dyeing process. In one non-limiting embodiment, the component is a liquid, and in another non-limiting embodiment is a vapor. In another non-limiting embodiment, the liquid or vapor may be applied through a bath, or through a thin soft liquid application system or through a liquid spray system or through a gas phase application system. The heat transfer liquid or vapor should be inert or benign so as not to damage the fabric, and may be any liquid or vapor consistent with this description. In one non-limiting embodiment, the heat transfer liquid comprises water, or the heat transfer vapor comprises steam.

In one non-limiting embodiment of the present disclosure, the disclosed HTHP treated woven fabric has 3l/dm when the fabric is not aged and when measured according to the test method described herein²Min or less, such as 2l/dm²Min or less, e.g. 1l/dm²Static Air Permeability (SAP) of/min or less.

In one non-limiting embodiment of the present disclosure, the HTHP treated woven fabric has a Dynamic Air Permeability (DAP) of 500mm/s or less, such as 200mm/s or less, for example 100mm/s or less, when the fabric is not aged and when measured according to the test method described herein.

In one non-limiting embodiment of the present disclosure, the HTHP treated woven fabric has a fabric tensile strength of 1000N or greater in both the warp and fill directions when the fabric is not aged. In another non-limiting embodiment of the present disclosure, the fabric has a tensile strength of 1500N or greater in both the warp and fill directions when the fabric is unaged. In another non-limiting embodiment of the present disclosure, the fabric has a tensile strength of 2000N or greater in both the warp and weft directions when the fabric is unaged. In one non-limiting embodiment of the present disclosure, the fabric has a tensile strength of 2500N or greater in both the warp and weft directions when the fabric is unaged. In yet another non-limiting embodiment of the present disclosure, the fabric has a tensile strength of 3000N or greater in both the warp and weft directions when the fabric is unaged.

In one non-limiting embodiment of the present disclosure, the treated fabric produced by the method described herein has a 1l/dm when the fabric is not aged²Static Air Permeability (SAP) of/min or less, Dynamic Air Permeability (DAP) of 500mm/s or less when the fabric is not aged, and tensile strength in both the warp and weft directions of 1000N or more when the fabric is not aged.

In one non-limiting embodiment, the disclosed HTHP treated fabric has a tear strength of 60N or greater in both the warp and fill directions when the fabric is not aged. In another non-limiting embodiment, the tear strength of the fabric is 120N or greater in both the warp and fill directions when the fabric is not aged. All tear strength values mentioned herein were measured according to a modification of ISO 13937-2 described below.

In one non-limiting embodiment, the slip resistance of the disclosed HTHP treated fabric is 150 or greater in both the warp and weft directions when the fabric is not aged. In another non-limiting embodiment, the slip resistance of the fabric is 175N or greater in both the warp and weft directions when the fabric is not aged. All slip resistance values mentioned herein were measured according to the modified version of ASTM D6479 described below.

In one non-limiting embodiment of the present disclosure, the treated fabric produced by the methods described herein has a Root Mean Square (RMS) surface roughness in the range of about 2 to about 70 μm, preferably about 5 to about 60 μm. All RMS values mentioned herein were measured according to the method described in the test methods section.

In one non-limiting embodiment, a portion of the filaments in the treated fabric have an aspect ratio of about 1.2: 1 to about 10: 1. Wherein the aspect ratio is 1: 1 describes a cross-section of the filaments having a common radius from their center to their outer surface. For example, filaments having a circular cross-section have an aspect ratio of 1: 1. The filaments on the surface of the fabric of the present invention have a flat cross-section in at least 1 dimension and thus have an aspect ratio > 1.2: 1.

Yet another aspect of the present disclosure relates to a method for accelerating the speed of a process performing hot roll calendering of a woven fabric to achieve a selected air permeability value, wherein the fabric has a tensile strength in the warp or weft direction of ≧ 1000N, the method comprising the step of hot roll calendering the fabric in the presence of an added heat transfer liquid or vapor, wherein at least one physical property of the fabric other than air permeability is improved as compared to the physical property of the same fabric calendered to achieve the selected air permeability value in the absence of the added heat transfer liquid or vapor.

In one non-limiting embodiment, the physical properties improved by hot roll calendering the fabric in the presence of added heat transfer liquid or vapor include at least one of: fabric tenacity, elongation at break, fabric toughness, tear strength, and slip resistance.

In one non-limiting embodiment, the resulting fabric has a tensile strength that is at least 85% of the tensile strength of the fabric prior to the hot roll calendering step.

In one non-limiting embodiment, the method further comprises applying an optional coating or film to the HTHP treated fabric to further reduce breathability. If the fabric is coated, any coating, web, net, laminate, or film known to those skilled in the art may be used to achieve the reduction in air permeability. Examples of suitable coatings include, but are not limited to, polychloroprene, silicone-based coatings, polydimethylene siloxane, polyurethane, and rubber compositions. Examples of suitable webs, nets and films include, but are not limited to, polyurethanes, polyacrylates, polyamides, polyesters, polyolefins, polyolefin elastomers, and blends and copolymers thereof. The film may be single or multi-layered and may be composed of any combination of webs, or films. In these embodiments, the fabric of the present invention can be used as a lower permeability and flatter substrate than a fabric of the same construction having a conventional amount of coating, film or laminate applied thereto. This would allow the application of lower weight coatings, or lighter or simplified web, laminate or film structures, and still meet very low permeability specifications.

The fabric produced according to the process described herein meets mechanical and performance criteria while limiting the weight and cost of the overall fabric. The disclosed fabric structure enables the application of lighter weight coatings and still achieves an impermeable fabric similar to that achievable with conventional non-HTHP treated fabrics.

Furthermore, the fabric produced according to the method of the present invention is expected to have improved heat resistance compared to the original fabric prior to HTHP treatment, without the need for additives, but rather by HTHP treatment. This enhanced heat resistance partially compensates for the improvement in heat resistance imparted by coating the fabric with conventional airbag coatings (such as, but not limited to, silicones) at conventional coating weights. The enhanced heat resistance improves the flexibility of the fabric to the hot air bag module inflator as compared to an uncoated fabric.

Furthermore, the fabrics of the present disclosure exhibit good packability compared to fabrics that have not been HTHP treated. As shown in the examples of the present disclosure, HTHP treated fabrics have improved packability over their untreated counterparts for a wide range of treatment conditions.

More specifically, the fabrics of the present disclosure are expected to exhibit improved uniformity of air permeability across the width of the fabric as compared to the original fabric prior to HTHP treatment. Conventional woven fabrics that are uncoated, do not include additives, or have films, webs, or webs adhered to them exhibit non-uniform air permeability characteristics across the width of the fabric, with a tendency for the permeability in the center of the fabric to decrease and increase toward and at the edges of the fabric. The necessity to compensate for this non-uniformity in permeability in the overall design of the fabric and airbag makes it possible to require the use of larger construction and heavier fabrics, or the addition of coatings. Both of these factors make the fabric less easily packaged. The fabric of the present disclosure can be used in lower construction and weight because of low and uniform permeability across the width of the fabric, and therefore no coating or a reduced amount of coating. This results in a more packagable fabric.

The present disclosure also provides articles formed from the woven fabrics and methods for their production as disclosed herein. In one non-limiting embodiment of the present disclosure, the fabric is used to produce products such as automotive airbags, canvasses, inflatable slides, temporary shelters, tents, pipes, coverings, and print media. As used herein, the term "airbag" includes airbag cushions. Airbag cushions are typically formed from a plurality of fabric panels and are rapidly inflatable. The fabric of the present disclosure may be used in an airbag sewn from multi-piece or single piece woven (OPW) fabric. The single piece woven (OPW) fabric may be made by any method known to those skilled in the art.

All patents, patent applications, test procedures, priority documents, articles, publications, manuals, and other documents cited herein are incorporated by reference in their entirety to the extent such disclosure is not inconsistent with this invention and all jurisdictions in which such incorporation is permitted.

Abbreviations

DAP-dynamic breathability

dtx-dtex

N66-Nylon 6, 6

PET-polyethylene terephthalate

SAP-static Permeability

SEM-scanning electron microscope

HTHP-high temperature high pressure

OPW single piece braiding