EP2635737A1

EP2635737A1 - Flame retarded textile and process for coating textile

Info

Publication number: EP2635737A1
Application number: EP11785844.9A
Authority: EP
Inventors: Jeffrey Stowell; Sergei V. Levchik
Original assignee: ICL IP America Inc
Current assignee: ICL IP America Inc
Priority date: 2010-11-04
Filing date: 2011-11-01
Publication date: 2013-09-11
Also published as: US20130260626A1; WO2012061373A1

Abstract

The present invention relates to solid phosphate ester, which can be used as a flame retardant in treatments for textile substrates. More specifically, the treatments for textiles substrates can be used as flame retardant formulations for application on textile fabrics while substantially maintaining the desired characteristics (aesthetic or textural properties) of the textile. The present invention thus further provides for articles having these phosphate ester formulations applied thereon, and of processes of applying them onto various textile substrates.

Description

FLAME RETARDED TEXTILE AND PROCESS FOR COATING TEXTILE

Field of the Invention

The present invention relates to the field of flame retardants (FRs) and, more particularly, to a flame retarded textile and a process of making the same.

Background of Invention

Textiles are an essential part of everyday life and are found, for example, in draperies, cloths, furniture and vehicle upholsteries, padding, toys, packaging material and many more applications. Consequently, textile flammability is of concern.

The flammability of fabrics is typically determined by the nature of the fiber comprising the fabric. Fabric flammability also depends on the fabric thickness and or looseness.

Several approaches have been proposed heretofore for retarding the flammability of flammable textiles:

One approach involves fiber copolymerization: several fiber monomers are mixed and copolymerized, thus improving the properties of a certain fiber (e.g., a flammable fiber) through the enhanced properties of another fiber (e.g., a fire resistant fiber).

However, this technique is limited by the number of existing fibers and their properties, and cannot be tailor-made for any substrate or requirements. Furthermore, fiber types and fiber polymerization types are not necessarily compatible, thus further limiting the applicability of this technique. An additional disadvantage of this approach is the high cost of the fire resistant fibers.

Another approach involves the introduction of flame retardant (FR) in or on the fabric, using one of three methodologies:

(i) Chemical post treatment: the fabric is treated with flame retardant chemicals after it has been produced, either by coating the fabric, or by the introduction of the FR into the fabric during the final dyeing process. The flame retardant can be applied to the back of the fabric (termed "back-coating") or to its front (termed "front-coating"), depending on the specific fabric application. For example, for draperies, furniture upholstering garments and linen, where the aesthetic appearance of the front side of the fabric is most important, back-coating is desired. Backcoating treatment transfers the flame retardant properties of the FR from the back side of the fibers/fabric, where the backcoating is located to the area on the front face of the fibers/fabric where a possible ignition source would present itself;

(ii) Fiber-additive matrix (also termed "compounding"): the FR is linked to the fiber during the melt spinning process, such that a fiber-additive molten plastic matrix is formed. This methodology has many drawbacks: (a) degradation of the FR agent due to the high extrusion temperatures, (b) reaction of the FR agent with the extruded fiber, and subsequent modification of the fiber properties, such as fiber dyeability, fiber

processability or other physical properties of the fiber, and (c) reaction of the FR agent with the various polymeric additives, such as dyes or catalysts; and,

(iii) Finishing of flame retardant additive onto fabric surface either directly or using finish chemicals (resins) which chemically link flame retardant to the fabric.

Disadvantages of this method are (a) usually finishes can be applied to cotton fibers, but they are not able to be effectively applied to synthetic fibers because of the absence of the necessary functional groups with which they would have to react in such an application, (b) some finishes use toxic chemicals like formaldehyde containing resins which can release formaldehyde, and (c) in some finishes gaseous ammonia is used as a curing agent.

Selecting the suitable flame retardant and the suitable methodology for applying it to the fabric largely depends on the specific textile substrate which has to be protected, e.g., the protection of a garment, or the protection of an electrical appliance will inherently pose different requirements and restrictions of the flame retardant used.

When used in textiles, an applied flame retardant should be: (a) compatible with the fabric, (b) non-damaging to the aesthetical and textural properties of the fabric, (c) transparent, (d) light stable, (e) resistant to extensive washing and cleaning, (f) environmentally and physiologically safe, (g) of low toxic gas emission, and (h) inexpensive. Above all, a flame retardant should pass the standard flammability tests in the field. Properties of the FR such as stability to UV light, heat, water, detergents and air- pollutants, as well as chemical stability, may be summed-up under the term "durability". The most durable textiles are those which are inherently flame retardant, or which contain reactive (chemically bound) flame retardants ((iii) above). In the latter, the degree of durability depends on the strength of the bonds between the flame retardant formulation and the fiber. Additive (mixed) flame retardants ((ii) above), or chemically applied flame retardants ((i) above) which are water-soluble, are considered less durable. Furthermore, topically applied FR agents ((i) above) are generally not as durable as those which are incorporated into the fabric during the extrusion of the fiber ((ii) above). Thus, the topically applied FR agent ((i) above) may be washed off during the laundry cycle, and in these cases the expensive and burdensome dry cleaning of the textile has to be used.

Among the main families of flame-retardant chemicals are halogenated flame retardants, primarily based on bromine and chlorine and phosphorus flame retardants.

Bromine-containing compounds and bromine/antimony-containing compounds have been long established as flame retardants, especially in the field of backcoating applications, the success of which is primarily dependent on their ability to function as effective vapor-phase flame retardants.

The use of aromatic bromines as flame retardants for textiles, however, suffers disadvantages including, for example, high bromine content demand, high dry add-on and/or binder demand, and a need to add compounds which enhance the flame retardancy. It is extremely undesirable to apply on a textile a flame retardant formulation in large amounts (also termed "high add-on") since high additive concentrations on the dry fabric results in inferior fabric properties, as well as increased cost of production. In addition, application of the noted flame retardants on fabrics may result in streak marks on dark fabrics, excessive dripping during combustion of thermoplastic fibers, relatively high level of smoldering and a general instability of the flame retardant dispersion which may prevent a uniform application thereof on the fabric. Further still, there has been a drive in the industry to either in part or wholly replace these halogenated flame retardants. Most of these drawbacks are inherent to the aromatic bromine compounds currently in use. In recent years there has been a significant effort made to develop and

commercialize phosphorus-based flame retardants in textile coating formulations.

Ongoing research has therefore been conducted in order to obtain flame-retardants with improved performance, which are less detrimental to textile properties.

There is thus a widely recognized need for flame retardant formulations devoid of the above limitations.

SUMMARY OF THE INVENTION

It is thus a purpose of this invention to provide a textile comprising a flame retardant effective amount of a flame retardant additive composition comprising a phosphate ester.

It is still another purpose of this invention to provide stable dispersions or suspensions of the target solid phosphate esters, or of mixtures thereof, thereby allowing the application of these solid phosphate esters to substrates via an aqueous application methodology commonly known to those skilled in the art (e.g., knife, spray, foam, froth, pad, etc.).

It has been surprisingly found that a textile can be rendered flame retardant with a solid phosphate ester.

In one embodiment herein there is provided a textile comprising a flame retardant effective amount of a flame retardant additive composition comprising a phosphate ester of the general formula (I):

wherein R¹, R², R³ and R⁴ each independently is aryl, or arylalkyl each independently containing up to about 30 carbon atoms, optionally interrupted with heteroatoms, X is a divalent aryl or arylalkyl group, containing up to about 20 carbon atoms, and n has an average value of from about 1.0 to about 2.0. In another embodiment herein there is provided a process comprising applying a flame retardant effective amount of a flame retardant additive composition comprising the above-identified phosphate ester of the general formula (I) to a textile substrate.

The term "fiber" as used hereinafter refers to a natural or synthetic filament capable of being spun into a yarn or made into a fabric.

The terms "fabric", "textile", "textile fabric" and "textile substrate" are used herein interchangeably to describe a sheet structure made from fibers.

Fabric durability, as it is commonly defined, is a fabric meeting its performance standard after 5, 10 or 50 washes.

The term "carrier", as used herein, describes an inert material with which the composition is mixed or formulated to facilitate its application, or its storage, transport and/or handling. The carrier can be, for example, an organic carrier (e.g., alcohols, ketones, petroleum fractions, aromatic or paraffinic hydrocarbons, chlorinated

hydrocarbons, or liquefied gases) or an aqueous carrier.

Since the flame retardant formulations described herein are particularly useful for the treatment of textiles, the carrier is preferably a textile acceptable carrier (e.g., water).

The term "textile acceptable carrier" as used herein refers to an inert, preferably environmentally acceptable carrier, which is not harmful to the textile.

As used herein, the term "flame retardant", describes a compound, a composition or a formulation which is capable of reducing or eliminating the tendency of a substance to sustain combustion when exposed to a small match-like or candle-like flame.

The "textile substrate" described herein can be a textile, film, laminant or other similar treatable surface which has a surface that can be beneficially coated (either wholly or partially) with the flame retardant additive composition, which may include interior surfaces of fibers of the textile as well as the interior of textile fibers in the textile.

As is used herein, the term "flammable substrate" describes a textile substrate that easily ignites when exposed to a small flame. The flammability of different textile substrates or of articles made of these textile substrates is typically tested and determined according to flammability test methods. Representative examples include the NFPA 701, MVSS 302 and BS5852, Part 1, a standard test method for flammability of upholstered furniture.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

wherein R¹, R², R³ and R⁴ each independently is aryl, or arylalkyi each independently containing up to about 30 carbon atoms, preferably up to 20 carbon atoms, most preferably up to about 15 carbon atoms, optionally interrupted with heteroatoms, the aryl group may be phenyl, cresyl, 2,6 xylenyl and the like, X is a divalent aryl or arylalkyi group, such as a divalent aryl or arylalkyi group containing up to about 20 carbon atoms, preferably up to about 16 carbon atoms, and n has an average value of from about 1.0 to about 2.0. Heteroatoms can comprise halogen, oxygen, nitrogen and sulfur. In one embodiment each of R¹, R², R³ and R⁴ are phenyl. In one embodiment X is a divalent phenylene group, preferably X is a divalent phenylene group so that the molecule of the general formula (I) is a hydroquinone bisphosphate, e.g., hydroquinone bisdiphenyl phosphate. X can comprise a divalent arylene group derived from a dihydric compound, for example, resorcinol, bisphenol-A, 4,4'-biphenol and the like.

In one embodiment herein, the solid phosphate ester is hydroquinone bis- phosphate flame retardant having the structure of formula (I), wherein preferably R¹, R², R³ and R⁴ each independently is a phenyl group, preferably a phenyl group of general formula (II): wherein each R independently is alkyl of 1 to 4 carbon atoms, each Z independently is chlorine or bromine, p is 0 to 3 and q is 0 to 5 with the sum of p and q being 0 to 5 and n has an average value of from about 1.0 to about 2.0, preferably from about 1.0 to less than or equal to about 1.2, and more preferably from about 1.0 to about 1.1. A

particularly preferred oligomenc bis-phosphate within formula (I) above is hydroquinone bis(diphenyl phosphate), i.e., R¹, R², R³ and R⁴ are each phenyl.

In one embodiment herein the phosphate ester of the general formula (I) is selected from the group consisting of hydroquinone bis(diphenyl phosphate), resorcinol bis(di-2,6-xylyl phosphate), 4,4'-biphenol bis(2,6-xylenol phosphate); and, combinations of any of the herein described phosphate esters.

In one embodiment the phosphate ester of the general formula (I) is present in an amount of from about 10 to about 90, specifically from about 20 to about 80 weight percent based on the total weight of the flame retardant additive composition.

According to one aspect of the invention, the flame retardant additive composition is in the form of a dispersion, e.g, an aqueous dispersion. In one embodiment herein, the flame retardant additive composition further comprises a carrier which can be selected from the group consisting of an aqueous carrier, an organic carrier and a combination thereof. Some non-limiting examples of organic carriers are alcohols, ketones, petroleum fractions, aromatic or paraffinic hydrocarbons, chlorinated hydrocarbons, or liquefied gases. Preferably the carrier is an aqueous carrier. More preferably the carrier is water. The amount of carrier can vary greatly provided that the carrier provides for a dispersion of the phosphate ester (I) which can be effectively coated onto a textile substrate to provide for reduced flammability of the textile. Generally the amount of carrier can be from about 20 to about 90 weight percent, most preferably from about 30 to about 60 weight percent based on the total weight of the flame retardant additive composition. It will be understood herein that all ranges recited for phosphate ester, carrier and binder mean that the flame retardant additive composition cannot contain more than 100 weight percent of all of the components therein, and thus, all ranges of weight percents being recited herein can be adjusted accordingly if there is present binder and/or carrier as well as other additional ingredients. In one embodiment the amount of binder and/or carrier and any optional additional ingredients (e.g. the endpoints of the herein recited ranges) will be adjusted accordingly based on the amount of phosphate ester (I) present in the flame retardant additive composition.

According to one embodiment herein, the flame retardant additive composition further comprises a binding agent (also termed herein interchangeably as a "binder"). The use of a binder is utilized to improve adhesion of the molecules of the phosphate ester, to the textile substrate.

A suitable binder can be selected depending on the specific application. For example, different binders may be suitable to attach the FR additive composition described herein to different textiles. Preferably, when the flame retardant additive compositions described herein are applied to the textile, the binder is selected to be most suitable for use on the specific textile being employed, i.e., it is selected to be both non- damaging to the aesthetical and textural properties of the fabric, and durable (to washing, drying, UV light etc.). The binder used in the formulations described herein is also selected to be compatible with the phosphate ester (I) and any additional additives in the flame retardant additive composition.

The binder can thus be selected from a large variety of materials, including, but not limited to, synthetic polymers, such as styrene-butadiene (SBR) copolymers, carboxylated-SBR copolymers, melamine resins, phenol-aldehyde resins, polyesters, polyamides, polyureas, polyvinylidene chloride, polyvinyl chloride (PVC), acrylic acid- methylmethacrylate copolymers, acetal copolymers, polyurethanes, mixtures thereof and cross-linked versions thereof. Preferably, the binding agent is selected from the group comprising of an acrylate, a polyurethane, a polyvinyl chloride (PVC) and combinations thereof. Most preferably, the binder used in the formulations described herein is an acrylate.

Examples of acrylates that are suitable for use as binders in the context of the present invention include, but are not limited to, 2-phenoxyethylacrylate, propoxylated 2 neopentyl glycol diacrylate, polyethylene glycol diacrylate, pentaerythritol triacrylate, 2- (2-ethoxyethoxy) ethyl acrylate, butyl acrylate, styrene acrylate copolymers, and others.

While the exact amount of binder used depends on the phosphate ester (Γ) and concentration, as well as the textile substrate onto which the flame retardant additive is applied, it has been shown that in the case of various textile substrates, the concentration of the binding agent in the flame retardant additive compositions described herein can be low, i.e., lower than 30 weight percent of the total weight of the flame retardant additive composition, preferably lower than 20 weight percent of the total weight of the flame retardant additive composition and most preferably less than 10 weight percent of the total weight of the flame retardant additive composition.

According to a still further aspect of the invention, the flame retardant additive composition further comprises at least one additional ingredient selected from the group consisting of an additional flame retardant, a smoldering suppressant, surface active agent, a wetting agent, a dispersing agent, a suspending agent, a thickening agent, a defoaming and/or antifoaming agent, a preservative and/or a stabilizing agent, a pH buffer, an additional solvent, a salt and, an oxide.

Examples of suitable optional additional flame retardants in the flame retardant additive composition include at least one of aromatic phosphates like triphenyl phosphate or alkylated triphenyl phosphates, dicyandiamide, melamine, melamine salts like melamine phosphate, melamine pyrophosphate, melamine polyphosphate and melamine cyanurate.

Examples of suitable smoldering suppressants include, but are not limited to urea, melamine and phosphate salts.

The surface active agents and/or wetting agents can be nonionic and/or ionic (cationic or anionic) agents.

Examples of nonionic surface active and/or wetting agents that are suitable for use in the context of the present invention include, but are not limited to, polyoxyethylene (POE) alkyl ethers, preferably NP-6 (Nonylphenol ethoxylate, 6 ethyleneoxide units) such as DisperByk® 101.

Examples of anionic surface active and/or wetting agents that are suitable for use in the context of the present invention include, but are not limited to, free acids or organic phosphate esters or the dioctyl ester of sodium sulfosuccinic acid.

Examples of dispersing agents and or suspending agents and/or thickening agents that are suitable for use in the context of the present invention include, but are not limited to, acrylic acids, acrylic acids ester copolymer neutralized sodium polycarboxyl such as naphthalene sulfonic acid- formaldehyde condensate sodium salt, alginates, cellulose derivatives and xanthan. In one non-limiting embodiment the thickening agent is carboxymethyl cellulose.

Examples of defoaming and/or antifoaming agents that are suitable for use in the context of the present invention, include, but are not limited to, mineral oil emulsions, natural oil emulsions, and preferably are silicon oil emulsions, such as AF-52.TM.

Examples of preserving and/or stabilizing agents that are suitable for use in the context of the present invention, include, but are not limited to, formaldehyde and alkyl hydroxy benzoates; preferably the preserving or stabilizing agents is a mixture of methyl and propyl hydroxy benzoates.

An optional additional solvent in the flame retardant additive composition can comprise any one or more of the carriers described above other than any initial carrier that is used in the flame retardant additive composition.

The textile can be selected from the non-limiting group consisting of synthetic textiles, natural textiles and blends thereof. Non-limiting examples of textile substrates that can be beneficially used in the context of the present invention include wool, silk, cotton, linen, hemp, ramie, jute, acetate fabric, acrylic fabric, latex, nylon, polyester, rayon, viscose, spandex, metallic composite, carbon or carbonized composite, and any combination thereof. Preferable non-limiting examples of textile fabrics which were shown to be suitable for use in the context of the present invention include, without limitation, cotton, polyester, and combinations thereof.

The textile utilized according to embodiments of the present invention may be used as a single layer or as part of a multi-layer protective garment.

A textile of the invention herein may be incorporated in various articles, where it is desired to reduce the flammability of textiles used in such articles.

Exemplary articles according to the present invention include any industrial product that comprises one or more textile, film, laminant or other similar treatable substrates and hence application of the FR additive composition described herein thereon is beneficial. Preferably, some exemplary non-limiting articles which comprise the textile containing the flame retardant additive composition described herein include, without limitation, furniture, toys, electrical appliances, a drapery, a garment, linen, bedding, a mattress, a carpet, a tent, a sleeping bag, a toy, a decorative fabric, an upholstery, a wall fabric and a curtain. One non-limiting article can be a technical textile. Technical textiles are textiles used in industrial, automotive, construction, agricultural, aerospace, hygiene, and similar applications.

Some articles, such as garments, linen and some decorative or technical textiles, are subject to harsh usage (abrasion, exposure to various environmental conditions etc.) and therefore may need extensive, sometimes daily, cleaning and washing. So far, fire proofing these articles involved either using the few available non-flammable fabrics; coating flammable fabrics with large amounts of FR, thus often damaging the fabric properties; or applying low amounts of FR on the flammable fabric, but limiting its cleaning method to the expensive and burdensome dry cleaning method. Using the FR additive compositions presented herein, these garments or technical textiles may be fire proofed while maintaining the feel and look of the fabric, as a result of applying relatively small amounts of the flame retardant additive composition described herein. The other types of articles in the list provided above, such as the non-limiting examples of draperies, carpets, tents, sleeping bags, toys, wall fabrics, decorative fabrics, mattresses and upholsteries, are not washed as much as garments or linen. However, these articles also call for efficient fire proofing thereof, while maintaining their durability during periodic cleaning. These articles may easily be made fire proof, either by using a textile treated by the flame retardant additive composition described herein during the manufacturing process, or by easily applying the flame retardant additive composition described herein onto the final product textile or article made therefrom.

According to another aspect of the invention the article comprising a textile substrate which contains the flame retardant additive composition described herein, is a flammable article prior to being contacted with the flame retardant additive composition described herein.

The article (as well as the textile contained in the article) described herein can be characterized by an after flame time of less than 120 seconds (sec), smoldering time of less than 15 minutes (min) and charring distance of less than 100 millimeters (mm), as defined by BS 5852 Part 1 of the 20 seconds ignition test, which is considered a pass of this test. According to a still further feature of the invention there is provided a textile substrate (e.g., a flammable textile substrate) in the article, which textile contains the flame retardant additive composition, wherein the textile is characterized by at least one aesthetic or textural property which aesthetic or textural property is identical to that of a textile substrate which does not contain the flame retardant additive composition.

Preferably, such an aesthetic or textural property is selected from the group consisting of flexibility, smoothness, color vivacity, and lack of streakiness. More preferably, these properties remain substantially unchanged upon subjecting the article to one or more washing cycles, and more preferably, to five or more washing cycles, and even more preferably to 25 or more washing cycles.

The flame retardant additive composition can be used in a flame retardant effective amount in the textile. A flame retardant effective amount will vary depending on the specific phosphate ester and textile, and other parameters.

According to still further aspects of the invention, the flame retardant effective amount of the flame retardant additive composition is characterized in that the dry amount of the flame retardant additive composition (dry add-on) is less than 100 weight percent of the textile substrate's dry weight. Preferably, the dry add-on is less than 75 weight percent of the textile substrate's dry weight. More preferably, the dry add-on is less than 50 weight percent of the textile substrate's dry weight, and most preferably the dry add-on is less than 30 weight percent of the textile substrate's dry weight. Thus, it should be appreciated that the textile substrates treated with the flame retardant additive compositions described herein are characterized by a relatively low dry add-on.

With regard to dry add-on calculation, the phrase "amount of the flame retardant additive composition" refers to the amount of non-volatile components within the flame retardant additive composition, which remain on the fabric after curing and drying. The dry add-on value is determined by calculating the difference in weight of the dry fabric before application of the flame retardant additive composition and after drying and curing of the applied of the flame retardant additive composition.

Examples of non- volatile components within the flame retardant additive composition, include, but are not limited to, phosphate ester(s) and binder(s). According to yet an additional aspect herein there is provided a process of applying any of the flame retardant additive compositions described herein, to a textile substrate, the process comprising contacting the textile substrate with the flame retardant additive composition described herein. Preferably, the contacting is effected by any industrially acceptable manner, preferably by spreading, padding, foaming and/or spraying means.

The process described herein of applying a flame retardant effective amount of a flame retardant additive composition comprising a phosphate ester of the general formula (I) described herein to a textile substrate may include wherein applying comprises contacting the textile substrate with the flame retardant additive composition described herein.

In one embodiment the step of applying can comprise immersing the textile substrate in the flame retardant additive composition described herein.

In one embodiment in the process described herein, following applying (e.g., contacting) the textile substrate with the flame retardant additive composition described herein, the process can further comprise subsequent to said applying, heating the textile substrate.

In one specific embodiment, the flame retardant additive composition described herein is contained in a layer such as a backing, back layer, or back-coating, referred to collectively herein as back-coating, that is applied to a surface of the textile. The back- coating is typically derived from a polymer compound ("binder" as described herein) and suitable liquid carrier material (as described herein) in which the selected phosphate ester (I) is dispersed. The selection of the polymer used in the back-coating is readily achievable by one having ordinary skill in the art. Typically the polymer of the back- coating can be selected from any of a large number of stable polymeric dispersions known and used for binding, coating, impregnating or related used, and may be of a self crosslinking type or externally crosslinked type. The polymeric constituent can be an addition polymer, a condensation polymer or a cellulose derivative. Alternatively, the back-coating may comprise conventional thermoplastic polymers, which can be applied to the textile by hot melt techniques known in the art. The back-coating (and the flame retardant additive composition described herein) can optionally include additional components, such as other fire retardants, synergists, dyes, wrinkle resist agents, foaming agents, buffers, pH stabilizers, fixing agents, stain repellants such as fluorocarbons, stain blocking agents, soil repellants, wetting agents, softeners, water repellants, stain release agents, optical brighteners, emulsifiers, thickeners, and surfactants.

The back-coating (and the flame retardant additive composition described herein) is typically formed by combining the polymer, liquid carrier material, optional components, if any, and selected flame retardant in any manner and order known, and the method and order is not critical to the instant invention.

Further, the back-coating (and the flame retardant additive composition described herein) can be applied to the surface of the textile through any means known in the art. For example, the use of coating machines such as those utilizing pressure rolls and chill rolls can be used, "knife" coating methods, by extrusion, coating methods, transfer methods, coating spraying, foaming or the like. The amount of back-coating (or flame retardant additive composition) applied to the textile is generally that amount sufficient to provide for a textile having a flame retarding amount of the designated phosphate ester (I). A flame retarding amount of the designated phosphate ester (I) is from about 80 to about 10 weight percent, specifically from about 70 to about 20 weight percent and , most specifically from about 60 to about 30 weight percent of phosphate ester (I) based on the weight of the flame retarded textile.

After application of the back-coating, the back-coating can be cured on the textile by heating or drying or in any way reacting/curing the back coating.

Padding is a process that is typically used for applying the flame retardant additive composition onto a textile substrate and is defined as a process in which the textile is first passed through a padder containing the FR additive composition wherein the composition is applied, and the textile is then squeezed between heavy rollers to remove any excess of the flame retardant additive composition.

The process described herein can be affected, for example, either during the dying or the finishing stages of the textile substrate manufacture. In another more specific embodiment herein there is provided a process comprising coating a textile substrate with the flame retardant additive composition described herein, preferably by any one or more of the aforementioned spreading, padding, foaming and/or spraying means.

According to still further features in the described preferred embodiments the processes described herein further comprise, subsequent to the contacting (or coating), heating the textile substrate. Preferably, the textile substrate is heated to a temperature of from about 100°C to about 200°C, preferably from about 150°C to about 170°C whereby the temperature is dictated by the curing temperature of the binder.

In one embodiment herein the flame retardant additive composition is packaged in a packaging material and is identified in print in or on the packaging material for use as a flame retardant for application on a textile substrate.

According to another embodiment of this aspect of the present invention, the process is conducted under basic pH conditions.

According to another embodiment of the process according to this aspect of the present invention, there is added to the flame retardant additive composition at least one additional ingredient as described herein.

Consequently, as previously delineated, the flame retardant additive compositions prepared by the process described herein, are characterized by an increased storage stability, being stable for at least two weeks at about room temperature, and often being stable for at least four weeks at that temperature. Stability is defined as no visual separation of suspension being observed.

The flame retardant additive compositions described herein can be efficiently used when applied on textiles, by avoiding the need to use excessive amounts of the flame retardant, binders, and other additives. Furthermore, these flame retardant additive compositions are easily applied onto the textile substrate.

Hence, according to another embodiment of the present invention, the article herein, which contains the textile containing the flame retardant additive composition described herein, is further characterized by at least one aesthetical or textural property which property is equivalent to an equivalent article which contains an equivalent textile which textile does not contain the flame retardant additive composition described herein. As a result, articles having textile substrates, treated by the flame retardant additive composition described herein have superior properties compared with the presently known FR-treated products.

According to the presently most preferred embodiments of the present invention, the article herein comprises a flammable textile which has been treated with the flame retardant additive composition herein.

There is also provided herein a dispersion of a flame retardant additive composition comprising a phosphate ester of the general formula (I) described herein; and, water. Such a dispersion can contain water in an amount of from about 20 to about 80 weight percent, specifically from about 30 to about 70 weight percent water based on the total weight of the aqueous dispersion. Such a dispersion can contain flame retardant additive composition in an amount of from about 20 to about 80 weight percent, specifically from about 30 to about 60 weight percent based on the total weight of the aqueous dispersion of flame retardant additive composition.

Such a dispersion can be provided by known methods and apparatus as are known in the art and will not be further described herein.

In another embodiment there is provided a process of treating a textile comprising applying the aqueous dispersion of phosphate ester of formula (I) to a textile substrate; still further there is provided a textile that has been treated by such a process; and even further there is provided an article comprising such a textile. Application of the aqueous dispersion of phosphate ester (I) can be done in any of the manners of application described herein and as is known in the art.

The formulations and processes described herein were practiced so as to provide textile substrates having the FR additive composition applied thereon. The resulting textile substrate is characterized by enhanced flame retardancy, while still maintaining its aesthetical and textural properties.

It is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the description herein. The invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting. Additional objects, advantages, and novel features of the present invention will become apparent to one ordinarily skilled in the art.

The following examples are offered to illustrate the general nature of the invention. Those skilled in the art will appreciate that they are not limiting to the scope and spirit of the invention and various and obvious modifications will occur to those skilled in the art.

EXAMPLE 1

A 53 wt% solids aqueous dispersion (4.4 wt% phosphorus) containing hydroquinone bis(diphenyl phosphate) as the sole flame retardant, an acrylic binder, dispersant and thickener was pad applied to 100% cotton twill fabric samples (spec. wt. = 168 g/m²).

The fabric samples were then dried and cured in an oven at 160°C for 4 minutes. The treated fabric samples were then tested and passed the criteria of the NFPA 701 (2010 version). The NFPA 701 is a small scale flammability test developed by the NFPA to assess the flame propagation of textiles and films. Testing measures the ignition resistance of a fabric after it is exposed to a flame for 45 seconds. The weight loss of the sample and observation of any burning fragments are the two main pass/fail criteria of the test. The fabric will pass the test if all samples meet the following criteria:

• The average weight loss of the specimens shall be 40% or less

• No individual specimen's percent weight loss can exceed the mean value for the specimens plus 3 standard deviations

• Fragments and residues of specimens that fall to the floor of the test chamber shall not burn for more than an average of 2 seconds per specimen The data for the evaluations are given in Table 1

Fabric: 100% White Cotton Twill (spec. wt. = 168 g/m²)

Formula Residue Content [wt%] = 53%

Table 1. Results of evaluation of padded textile according to NFPA 701

EXAMPLE 2

A 50 wt% solids aqueous dispersion (4.0 wt% phosphorus) containing hydroquinone bis(diphenyl phosphate) as the sole flame retardant, an acrylic binder, dispersant and thickener was pad applied to 100% cotton twill fabric samples (spec. wt. = 168 g/m²).

The data for the evaluations are given in Table 2

Fabric: 100% White Cotton Twill (spec. wt. = 168 g/m²)

Formula Residue Content [wt%] = 50%

Table 2. Results of evaluation of padded textile according to NFPA 701

The dry add-on values for each sample above were determined by measuring and then calculating the difference in weight of a "bone-dry" (conditioned at 105°C for 30 minutes) fabric sample and one that was coated and fully cured. The FR and phosphorus loading levels were calculated based on the known level of solid flame retardant (and %P in that flame retardant) added to the aqueous dispersion formulation in relation to the solids content in the final application dispersion (both calculated and confirmed by performing a "% solids" determination on the final dispersion). The dry add-on values shown above express the amount of solid in the aqueous dispersion that were applied to each fabric sample; and based on knowing the percent of solid flame retardant in the overall formulation, the FR and phosphorus add-on levels were calculated.

EXAMPLE 3

A 50 wt% solids aqueous dispersion (4.1 wt% phosphorus) containing hydroquinone bis(diphenyl phosphate) as the sole flame retardant, an acrylic binder, dispersant and thickener was pad applied to 100% cotton twill fabric samples (spec. wt. = 258 g/m²).

The fabric samples were then dried and cured in an oven at 160°C for 4 minutes. The finished fabric samples were tested and passed the MVSS 302 with either an SE or SE/NBR rating. The MVSS 302 test is a horizontal flame test that is used as a guideline for automobile manufacturers. The sample size is 14 inch x 4 inch x ½ inch. There is a line 1 ½ inch from the ignition point. A flame is ignited for 15 seconds. The ignition source is then turned off and the sample is rated. A "DNI" rating indicates that the sample did not support combustion. A rating of "SE" indicates that the sample ignited but did not burn to the timing zone, which is a point starting from the 1½ inch mark to the 3½ inch line. A rating of "SENBR" indicates that the sample burned past the 1½ inch line but was extinguished before the 3½ inch mark. A rating of "SE/B" indicates that a sample burned past the 3½ inch mark but extinguished before the end point; an inch per minute rate is then calculated. The data for the evaluations are given in Table 3

Fabric: 100% White Cotton Twill (spec. wt. = 258 g/m²)

Formula Residue Content [wt%] = 50%

Table 3. Results of evaluation of padded textile according to MVSS 302

While the process of the invention has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out the process of the invention but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

CLAIMS:

1. A textile comprising a flame retardant effective amount of a flame retardant additive composition comprising a phosphate ester of the general formula (I):

wherein R¹, R², R³ and R⁴ each independently is aryl, or arylalkyl each independently containing up to about 30 carbon atoms, optionally interrupted with heteroatoms, X is a divalent aryl or arylalkyl group, containing up to about 20 carbon atoms, and n has an average value of from about 1.0 to about 2.0.

2. The textile of Claim I wherein each of R¹, R², R³ and R⁴ are phenyl, X is a divalent phenylene group, and n is one.

3. The textile of claim 1 , wherein the textile which contains the flame retardant additive composition passes the NFPA 701 and MVSS 302 tests.

4. A process comprising applying a flame retardant effective amount of a flame retardant additive composition comprising a phosphate ester of the general formula (I):

wherein R¹, R², R³ and R⁴ each independently is aryl, or arylalkyl each independently containing up to about 30 carbon atoms, optionally interrupted with heteroatoms, X is a divalent aryl or arylalkyl group, containing up to about 20 carbon atoms, and n has an average value of from about 1.0 to about 2.0, to a textile substrate.

5. The process of Claim 4 wherein each of R¹, R², R³ and R⁴ are phenyl, X is a divalent phenylene group, and n is one.

6. The process of Claim 4 wherein the step of applying comprises contacting the textile substrate with the flame retardant additive composition comprising the phosphate ester (I).

7. The process of Claim 4 wherein the step of applying comprises backcoating the textile substrate with the flame retardant additive composition comprising the phosphate ester (I).

8. The process of Claim 4 wherein the step of applying comprises immersing the textile substrate in a flame retardant additive composition comprising the phosphate ester (I).

9. The process of Claim 6, further comprising, subsequent to said contacting, heating the textile substrate.

An article comprising the textile of Claim 1.

11. The article of Claim 10 wherein the article is selected from the group consisting of furniture, a drapery, a garment, linen, a mattress, a carpet, a tent, a sleeping bag, a toy, a decorative fabric, an upholstery, a wall fabric, a curtain, carpeting, a technical textile and combinations thereof.

12. A dispersion of a flame retardant additive composition comprising a phosphate ester of the general formula (I):

wherein R¹, R², R³ and R⁴ each independently is aryl, or arylalkyl each independently containing up to about 30 carbon atoms, optionally interrupted with heteroatoms, X is a divalent aryl or arylalkyl group, containing up to about 20 carbon atoms, and n has an average value of from about 1.0 to about 2.0; and, water.

13. A process of treating a textile comprising applying the dispersion of Claim 12 to a textile substrate.

14. A textile that has been treated by the process of Claim 13.

15. An article comprising the textile of Claim 14.

16. The article of Claim 15 wherein the article is selected from the group consisting of furniture, a drapery, a garment, linen, a mattress, a carpet, a tent, a sleeping bag, a toy, a decorative fabric, an upholstery, a wall fabric, a curtain, carpeting, a technical textile and combinations thereof.