DE2117999A1 - - Google Patents

Description

DR. BERG DIPL.-ING. STAPF PATENT LAWYERS 91 170QQ

8 MUNICH 8O. MAUERKIRCHERSTR. AS L · \ \ I ΌΌΌ

Dr. Berg Dipl.-Ing. Stapf, 8 MOndien 80, MouerkircherstroBa 45

Your reference Your letter Our reference 20640 Dohim | ΗιΑρΓΪΙ | 5 "/ 1

Attorney file 20 840

Monsanto Company St. Louis, Missouri / USA

Fire retardant bonded nonwoven product and process for its manufacture

This invention relates to fire retardant nonwoven bonded products using a binder preparation containing an ethylene / vinyl chloride copolymer and contains an ammonium polyphosphate.

Under the name "fiber fleece" (non-woven fiber material), the way it is used here is a reprehensible

Be / My - 2 -

109848/1834

stig "fce fiber mass, which by means of mechanical, chemical, pneumatic, electrical or vacuum or otherwise deposited and in the desired Shaping is either flat (as webs, mats or sheets) or three-dimensional.

Nonwovens can be produced by both wet and dry processes. In the wet process, the Fibers in water or a similar inert liquid slurried. The slurry is on a flat surface sprayed, drain the inert liquid and the Web that is under pressure to form the loosely consolidated Hate dried out randomly distributed fibers. In the dry process, the fibers are in a dry state on a solid, flat surface, such as a conveyor belt, by means of mechanical or pneumatic Process, for example with a coating or air deposition machine, dejected. The drying process can cause the fibers to deposit in either random or oriented distribution. A mail-in discussion of the manufacture of nonwoven fabric is provided in "Non Woven Fabrics" from F.N. Buresh-Reinhold Publishing Company, New York, N.Y. (1962). '

Regardless of the production of the nonwoven fabric -Procedure used has the material at this point

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just a loose _# loose structure without real tensile strength - although it is unsuitable * to get it as a unitary piece without asking. In order to give the iäservliis diö the necessary tensile strength and Köhäsiön for practical purposes, it is necessary that dd§. Fibers bound and tied in a certain way Vssw. To be brought together. Bas' ste and economical Verfahrenidas napkins, and other access to reach the fibers - consists daring that barren saturating the nonwoven fabric with a binder impregnated, after which it is heated or subjected ~ vierungsverfahren another Äktl to the binder to coalesce and fuse UNAE the FaserrL to bind and interlock or to bring together *

For many purposes it is essential that the bonded fiber fleece both good elongation> resistance granted Oils and solvents, good draping and processing properties, exhibit good fire retardancy and no discoloration as well as high tensile strength *

Various, for general purposes so far synthetic polymers and plasticizers as a binding agent for nonwoven products these prior art polymers form un desired stiff products that are suitable for i

109841/1834 " ⁴ "

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are unsuitable because they have poor draping properties a / ufw ^ stn * sich, hard: to the touch and difficult to process are other polymers according to the state of technology discoloration and loss of strength if exposed to bleach while washing. Still other polymers produce bound! which have adequate tensile strength and elongation but lack acceptable fire retardancy. in the in general, the binders used up to now are total · ^ not satisfactory either.

According to this invention, it has been found that fire retardant bonded nonwovens have both good fire retardancy and the desirable combination of high tensile strength and elongation as well as good processing and draping properties can be obtained by having a binder preparation is used for the fiber fleece, which is an ethylene / vinyl chloride copolymer and a Immonium polyphosphate contains fire retardant.

Are the fieuerhemmendien means bound to form ?: jaseryliese with Feuerhemjnung according to this invention, suitable are, flowing substantially water-insoluble ammonium polyphosphate of general formula e

-5-

where η is an integer with a larger average value than 10, m / n has an average value between 0.7 and about 1.1, and m an average value which is equal to n + 2. These polymeric polyphosphates have P-O-P type bonds and that the average value of η is larger than 10 is confirmed by the paper chromatography method (Karl-Kroupa, Anal. Chem., 28, 1091, 1956) and that the polymeric bond of the P-O-P type is detected by nuclear magnetic resonance spectra which show that there are essentially no bonds of the P-N-P type and not ortho-, pyro- or short-chain Groups of the P-O-P type are present, as well as by Infrared spectra showing that bonds of the P-O-P type, but essentially no any P-N type bonds exist.

These polymeric ammonium polyphosphates can either have straight or branched chain structures. It should be noted that essentially all of the nitrogen in these ammonium polyphosphates is present as ammonia nitrogen and that in the polyphosphates essentially no nuclear nitrogen is present. Although theoretically the ammonia nitrogen to phosphorus molar ratio reaches about 1 in the polyphosphates of the present invention when the polyphosphates are in the ammonium form are transferred, in some cases the molar ratio

109845/1834 " ⁶ "

never ammonium nitrogen to phosphorus less than 1, and it is contemplated in accordance with this invention that only polymeric ammonium polyphosphates whose molar ratio is not less than about 0.7 are used. In addition, when the polyphosphates of the present invention are characterized here in such a way that they are substantially insoluble in water, which is to be understood that the solubility of a slurry of 10 g of solids / 100 cc of water after 60 minutes at 25 ⁰ C for about 5 g / 100 ecm of water or less. For the purposes of the present invention, this means in detail that for an ammonium polyphosphate with a solubility of a specified value, this refers to the solubility value in g / 100 ecm of water when 10 g of the specified polyphosphate in 100 ecm of water at 25 ° C. for 60 minutes be slurried.

The degree of polymerization of the substantially water-insoluble ammonium polyphosphates is difficult to determine, because the known methods for determining the so called ^{w 1} * solution process, ie, it can be used for Polymerisationsmessungen solution techniques. If, for example, the polymerization measurement after the. End group titration process (Van Wazer, Griffith and McCullough, Anal. Chem., 26, 1755 (1954)) after conversion of the ammonium polyphosphate into the acid form by means of ion exchange resins (Van Wazer and Holst, J. Am. Chem. Soc,

109845/1834 " ⁷ "

72 ,, 639 (195O)), the DurchSGhnittswext warn. η about 20 to about 400, preferably about 40 to about 400, while in the determination according to the scattered light method or according to the viscosity correlations as obtained from light scattering (Strauss and Wineman, J. Am. Chem. Soc., 80, 2366 ( 1958)), modified using the Zimm representation method (Stacey "Light-Seattering in Physical Chemistry, ™ BUtterworths, London 1956)) the average value for η over about 500 and preferably in the range from about 500 to about 100,000, in particular from about 1000 to about JO000.

The term "ammonia nitrogen" refers to the nitrogen which is present in the form of ammonium ions and which can be removed by 'the hydrogen form of a strong cation exchange resin', ie the hydrogen form of a sulfonate polystyrene resin. The term "non-ammoniacal ^{nitrogen" or "nuclear nitrogen * 1"} refers to the nitrogen that cannot be removed in the same way as real ammoniacal nitrogen.

The ammonium polyphosphates can be made in many different crystalline forms, such as this can be recognized by the X-ray diffraction patterns, and in general all such forms (although

"■ - 8 -

the following forms 1 and 2 "are preferred) and, the non-crystalline or amorphous forms are used * The following table provides an explanation crystalline forms of ammonium polyphosphates that lead to Are suitable for use ».

Ca) X-ray scatter information ^ '

Form 1 d, £ I. 6.06 Form 2 Shape 3 Form 4 Diffraction 5.47 d, £ d, £ d, £ shine ^
_ - - 3.83 1 3.50 5.70 6.65 5.70 2 3.24 6.06 5.68 5 * 60 3 3.08 5.40 3.42 4th 2.93 3.52 7.00 5 3.37 3.80 6.10

(a) CuK OC radiation

(H) The five strongest diffraction rays in the order of decreasing intensity

In general, the ammonium polyphosphates of any size can be used which enable them to be incorporated into the ethylene / vinyl chloride copolymers. In particular, ammonium polyphosphates which have a particle size small enough to pass through a sieve with a mesh size of OjIy ⁷ mm (80 mesh USSS) are preferred, with one in particular

109845/1834 "," ⁹ "

Particle size is preferred which is at least small enough that the! Particles pass through a sieve with a clear Mesh size of 74 / U go (200 mesh USSS).

The essentially water-insoluble: ammonium polyphosphate fire-retardant component of the binder preparations useful according to this invention can be prepared by many and different processes. In general, a phosphate-containing material such as monoammonium-o-phosphate, diammonium-o-phosphate, condensed phosphoric acid, o-phosphoric acid and the like is thermally treated with an ammonium-forming and condensing agent such as urea, ammonium carbonate, biuret, sulfamide, sulfamic acid, ammonium sulfamate, Condensed guanylurea, methylurea, pormamide-aminourea, 1,3-diaminourea, biurea and the like. In particular, for example, monoammonium-o-phosphate and urea can be thermally condensed to form essentially water-insoluble ammonium polyphosphates, for which purpose a melt formed from essentially equimolar amounts is ^{heat-treated at a temperature of about 250 0} O for about 3 hours.

The ethylene / vinyl chloride copolymers that are used to produce the fire-retardant, bonded nonwovens of these Invention are suitable, contain about 5 to.

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about 70 weight percent ethylene, about 30 to about 95 weight percent vinyl chloride, and about 0.1 to about 10 weight percent additional polar monomer components. The additional polar monomeric component can be completely acrylamide or part of the acrylamide can be replaced by one or more polar monomers, namely acrylonitrile, methacrylonitrile, N- (lower-alkyl) -acrylamide, Έ- (lower-alkyl) -methacrylamide and N- (hydroxy-substituted-lower-alkyl) -acrylamide with 1 to 3 carbon atoms in the lower-alkyl groups, N- / ~ "2- (2-methyl-4-oxopentyl) __ 7-aorylamide, acrylic acid, methacrylic acid, and alkali metals and ammonium salts of acrylic - and methacrylic acids, maleic acid, fumaric acid, half and full alkali metal and ammonium salts of maleic and fumaric acid, aconitic acid, itaconic acid, citraconic acid and alkali metal and ammonium salts thereof, acrylyl and methaerylyl esters of hydroxyalkanoic acids with 2 to about 6 carbon atoms in the alkylacrylamides, acrylyl amides and methacrylic amides of aminoalkanoic acids with 2 to about 6 carbon atoms in the aminoalkanoic acid, hydroxyethyl and hydroxypropyl esters of acrylic, Methacrylic, maleic and fumaric acids, vinyl esters of. Alkanoic acids with 1 to 6 carbon atoms such as vinyl acetate, vinyl propionate and low-alkyl (1 to 6 carbon atoms) sulfonic acids, vinyl esters of phenylsulfonic acids and alkylphenylsulfonic acids. and acrylyl and methacrylyl esters of

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Hydroxyalkylsulfanic acids having 1 to 6 carbon atoms in the alkyl and / or hydroxyalkyl sulfonamides with 1 Ms 6 carbon atoms in the hydroxyalkyia parts. The polar monomeric component generally contains at least 50 μmd, preferably at least 50 μm. 56. Acrylamide,

The copolymers are therefore at least terpolymers, which contain ethylene, vinyl chloride and acrylamide, but can also be quaternary or higher polymers be the one or more of the above in exemplary Catfish specified additional polar monomers contained in small amounts. Generally will such additional polar monomers are not present in the copolymers in amounts greater than about 3% by weight be.

It is preferred that the interpolymer contain from about 5 to about 70 # ethylene, 30 to about 95 # vinyl chloride and contains from about 1 to about 5 # acrylamide. A specific example of such a copolymer is a terpolymer containing about 19 to about 25 # ethylene, about 74 to about 8ji vinyl chloride and contains from about 2 to about 4 # acrylamide.

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The copolymers used according to the invention are generally not modified, but modified copolymers can also be used according to the invention. The copolymers are particularly amenable to hydrolytic modification, for which small amounts of strongly alkaline materials such as alkali metal hydroxide or a quaternary ammonium hydroxide such as tetramethylammonium hydroxide or a strong acid such as mineral acids, e.g. hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, are used. Preferably has the base or acid used has a higher ionization than 10 ~ ⁴ at 25 ⁰ C

The hydrolytic modification is carried out in the manner that an aqueous dispersion or the polymer latex of ethylene, vinyl chloride and acrylamide with aqueous base or acid in an amount ranging from about 0.1 to about 100% of the amide equivalents in the mixed polymer is chemically aqureeLent.

For specific examples of polar monomers which, as described above, to replace part of the acrylamides, in the polar monomeric component used in this invention Usable copolymers that can be used include acrylonitrile, N-methacrylamide, N-ethyl acrylamide, N-propylacrylamide, N-hydroxymethylacrylamide, meth-

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acrylamide, acrylic, methacrylic, maleic, fumaric, itacon, Aconite and citraconic acids and the alkali metal and ammonium salts of these acids, preferably the sodium, Potassium or ammonium salts, allyl esters of these acids, e.g. methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, Butyl methacrylate, ethyl methacrylate, monoethyl maleate, Dipropyl fumarate, acrylyl 3-hydroxypropionate, Methacrylylhexamide, 2-hydroxyethyl and 2-hydroxypropyl esters from acrylic, methacrylic, male, iWar, Itaconic, aconitic and citraconic acids, vinyl formate, vinyl acetate, vinyl hexanoate, vinyl and alkyl esters of propanesulfonic acid, Vinyl phenyl sulfonate, acrylyl and methacrylyl esters of 2-hydroxypropylsulfonic acid and N-acrylyl and li-methacrylyr-2-hydroxypropanamides.

Copolymers, the "for example in the binder preparations can be used for the fire retardant bonded nonwovens of this invention Ethylene / vinyl chloride / acrylamide, ethylene / vinyl chloride / hydroxyethyl acrylate, ethylene / vinyl chloride / acrylamide / N-isopropyl acrylamide, Ethylene / vinyl chloride / acrylamide / N-ethy! Methacrylamide, Ethylene / vinyl chloride / acrylamide Z-diammonium itconate, Ethylene / vinyl chloride / acrylamide / monobutyl acid maleate, Ethylene / vinyl chloride / acrylamide / N-meth-. acrylylpropionamide, ethylene / vinyl chloride / aorylamide / sodium acrylate and ethylene / vinyl chloride / acrylamide / sodium methacrylate.

1098A5 / 183A - _u _

The fire retardant bonded nonwovens of this invention can be made from either natural or synthetic Fibers or a mixture thereof are produced, the selection of the fiber being based solely on the intended specific end use for the bonded fiber product is dependent. The fibers that can be used according to this invention include natural fibers such as wood, jute, sisal, hemp, cotton, cotton linters, Silk, mohair, cashmere, asbestos, wool and fflas, and synthetic fibers, for example rayon, cellulose esters such as cellulose acetate, polyvinyl chloride, polyvinyl acetate, Polyacrylonitrile and their copolymers, polyethylene, polypropylene and the like., Polyesters such as ethylene glycol serephthalate polymers and nylon type polyamides.

For many purposes, the fire retardant, tied Nonwovens of this invention made from a variety of natural fibers or a variety of synthetic fibers or made from a mixture of natural and synthetic fibers. Mixtures of wood and cotton fibers can be beneficial for end products such as; Shoe clothing and the like. are used »In general, wood fibers form the main component of the fiber content in bonded nonwoven products. Combinations of glass and asbestos fibers are generally used for

109846 / 183-4- '-15-

Used for isolation purposes. Combinations of glass and Wood fibers are suitable for certain draperies. That Glass fiber: cellulose fiber weight ratio in such bonded nonwovens is usually in the range of about 1sIO to about 10: 1.

A mixture of wood and nylon fibers or a mixture of wood and rayon fibers can be used for clothing can be used advantageously. Mixtures of wood and nylon fibers and blends of wood and polyester fibers are also used for various purposes where a reinforcing material is required. With such mixtures of natural and synthetic fibers, the weight ratio is natural to synthetic Fiber generally from about 1:20 to 20: 1, and preferably from about 1: 1 to about 3: 1.

The nonwovens useful in making the fire retardant bonded nonwovens of this invention can be made by any known method. Thus, nonwovens can be made from fibers that are oriented or aligned both randomly and along an axis. Fiber materials in the form of two-dimensional, endless webs can according to the. following procedures. Oriented tracks are made using conventional machines

10984571834 " ¹⁶ "

for web production such as shredders, drivers, scrapers, or (Garnett) carding is used. Cross-laid webs are made in a similar manner made as oriented webs except that the fibers are "carefully at right angles to the machine direction be arranged to improve strength crosswise.

Random webs are made with machines using air-lay machines and: the nonwovens have the same strength in all directions. In the luff deposition process, continuous filaments are passed through a cutting or breaking device which releases the fibers to the discharge of a blower. Suitable lines are provided to feed the fibers to a collecting sieve or air-permeable structures which collect the fibers in the desired shape. The screen may be in the form of an endless conveyor belt which runs through the lower part of a tower, in the upper part of which the fibers moved by air are introduced through the conduit. A suction device can be provided under the belt screen to aid in the deposition of the fibers. Instead of using a flat belt screen, a stationarily formed screen can be used. For example, such a sieve can have the shape of a hat cone, as it is in the felt hat manufacturer

109 84 5 /. 18-3 A ■ -1.7-

lund "is used, but ^ s can also have other forms are used which are suitable for producing the desired shape of the bonded nonwoven fabric such as, for example a right-angled sieve. As in the case of the endless conveyor belt, a suction device can be installed underneath of the stationary screen to aid in the deposition of the fibers.

Endless paths in random fiber distribution are also used produced by the direct spray method from a solution or molten mass of the fiber material. It is this the traditional method of making materials from fiberglass and mineral wool as well made of nylon or thermoplastic materials dissolved or melted in a suitable solvent could be. The solution or melt is fed to suitable nozzles or jet-forming outlet openings and a high pressure stream of a flowing medium such as air, nitrogen or steam becomes so against the current or the Currents of the fiber-forming material directed that these are interrupted and as fibers near the outlet openings be coagulated. Electrostatic filament forming processes can also be used for this purpose. As with the use of blowers, the can be interrupted and disperse fibers to the top of a settling tower where they can be removed with the help of suction

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devices on a suitable belt or stationary The sieve can settle at the bottom of the tower * This process is / especially for the production of fibers from silicon-containing Material such as glass or mineral wool, but also suitable for thermoplastic resin fibers.

The webs are made of wet, randomly arranged pasers from a slurry of dispersed fibers on paper or modified paper machines. Web-connected webs are made up of additionally oriented continuous ones Formed threads that are bound or glued at the crossover points. The process involves extruding continuous filaments that Stretching to orient the fiber, a certain fiber confusion or-entanglement by means of liquids or air and binding or gluing at the crossing points.

The fire retardant nonwoven bonded products of this invention are generally made in one process placed, in which the loose fibers are wrapped in a non-woven fabric solidified, which has the structural design of the desired, bonded fiber fleece product, the binder preparation, an ethylene / vinyl chloride copolymer and a. Contains phosphorus and nitrogen fire retardant, dispersed in the fiber fleece and the impregnated fiber

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Fleece heated to a temperature that is sufficient to allow the copolymer to flow together and melt to bring, and optionally heated to a temperature sufficient to crosslink the copolymer, if a sulfur crosslinking agent is used.

A further process for preparing the fire-retardant, bonded fibrous non-woven products of this invention, which is particularly useful when the nonwoven fabric according to the air-deposition method in an ^{"air-lay-! L} machine is formed, is that the fibers with the binder formulation, the ethylene / Vinyl chloride copolymer and phosphorus and nitrogen fire retardant containing, in dispersion or powder form in contact as they fall through the 'settling chamber to the point of deposition Introduces binder formulation into the settling chamber at some intermediate point between the top and the bottom.By spraying the fibers as they lower to the collection point, it is possible to achieve a thorough distribution of the binder formulation onto the fibers before they are collected in the nonwoven fabric In the manufacture of certain fiber product e, in which a hot melted mass of a polymer such as nylon

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or a molten, silicon-containing mass or glass interrupted by flows of heated air or steam, the binder preparation can be in the form of the dispersion or as. Powder can be sprayed immediately on the pasers while they are still hot, leaving immediately after the deposition, the binder sets and the fibers binds in a suitable ratio and with each other attached.

The binder preparations can be applied to the fibers of the Nonwovens can be applied by all known methods. The binder formulations are common applied to the fibers of the nonwovens by applying them to the surface or that Nonwoven into a liquid, thickened or foamed Dispersion is immersed so that the binder preparation penetrates into the interior of the fiber fleece. Unless that nonwoven fiber material is a two-dimensional structure in the form of a nonwoven or a web Binder preparations usually in the form of an aqueous Dispersion applied. In a typical application, the fibrous sheetlike structure is impregnated with the binder preparations, for which purpose the structure is incorporated into the dispersion dips or hangs to ensure sufficient wet absorption of the binder. The wetted, wet fiber material in the form of a fleece or a web can through

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a pair of pressure rollers are passed to a substantially to effect uniform impregnation and further control the amount of binder applied. The impregnated fiber fleece is dried by conventional methods in order to cover the entire or a rope of the Removing water and the confluence and melting the binding agent preparation in the fiber fleece zu.bewirken. The drying temperature and the drying time are dependent on the size, shape and cross-section of the impregnated fiber fleece. In general the drying temperature is controlled so that none recognizable destruction or degradation of the fiber as well as the Binder preparation occurs.

When the binder preparations are used in the form of a dispersion, the dispersion contains approximately 5 to about 90 wt.% Ethylene / vinyl chloride copolymer and from about 0.1 to about $ 300 Ammonium polyphosphate, based on the copolymer. Such dispersions preferably contain from about 10 to about 60% by weight copolymer and from about 1 to about 30% ammonium polyphosphate to make them easy to use by dipping, soaking, spraying and the like.

The amount of ethylene / vinyl chloride copolymer, based

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on the weight of the fiber in the bonded fiber fleece, can vary widely according to the desired properties of the end product and the specific end use « The fire retardant bonded nonwoven products of these Invention generally contain from about 2 to About $ 200 copolymer based on the weight of the fibers. For the production of preforms in molded articles are to be converted, it is preferred to use from about 2 to about 10 $ ethylene / Vinyl chloride copolymer, based on the fiber weight, to be used. In the manufacture of insulation materials, the amount of ethylene / vinyl chloride mixed polymer used falls generally in the lower part of the above range when the binder applied primarily in the area of the surface or surfaces of the product or when it is together is applied with other binders.

When the ethylene / vinyl chloride copolymer serves primarily to bond the fibers together to form a fire retardant, bonded nonwoven product, while maintaining maximum porosity combined with minimal change in fiber processing and draping properties and increasing tensile strength , should, are preferably from about 10 to about 70 wt.

109845/1834 " ²³ ~

polymer solids, based on the fiber content, used. The lower part of this range generally provides maximum and minimal porosity Change in the handling and draping properties of the paser, albeit at a higher proportion within this area the porosity is still substantially maintained and the fiber handling and - Drapery properties are still present. The so obtained fire-retardant, bonded nonwovens advantageously for many sanitary purposes such as napkins, children's bibs, table towels, disposable diapers, and disposable towels used. When this amount of interpolymer is used, relatively little or no occurs "Window pane formation" sis. » i.e. the spaces between the fibers remain open to form a highly porous, voluminous product. If desired, the Density of the product can be modified by looking for different sizes of pressure before or in many cases after the saturated nonwoven fabric has been heated to bond, applies.

The fire retardant, bonded nonwoven products from about 30 to about 150 wt. of ethylene / vinyl chloride mixed olymerisate, based on the weight of the fiber, are generally used in the clothing industry for the production of intermediate linings or inserts for

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Coats, suits, collars, cuffs and the like. And for Manufacture of clothing fabrics for outerwear such as blouses, backs, shirts, dresses and the like. The fire-retardant, bonded nonwovens, the copolymers Included in this area are also suitable as curtain and drapery materials. Besides the uses In the home and for clothing, the fire-retardant, bonded nonwovens of this invention can be used with 10 to 10 ° wt. ^ Copolymer, based on the weight of the Paser, used in light industry as wiping cloths, filters and as a lining for packaging.

The amount of ammonium polyphosphate based on the weight of the fiber constituent of the fire retardant bound Nonwoven fabrics of this invention can, from about 1 to about 30, and preferably from about 3 to about 20 wt. $ Vary.

If desired, the binder formulations useful in accordance with this invention can further include a Contains wetting or foaming agents. They can also contain a defoaming agent if the Constituents of the aqueous dispersion have the tendency To allow foaming to occur, and if such foaming is undesirable. The conventional Wetting agents such as the sodium salt of dioctyl succinic acid and the conventional foaming and defoaming

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agents such as sodium soap including sodium oleate for foaming and octyl alcohol or certain silicone antifoams can be used for defoaming.

In many cases, the properties of the fire-retardant, bonded nonwovens are significantly improved by thermosetting the copolymer, which causes crosslinking. Ethylene / vinyl chloride copolymers can be crosslinked with various sulfur-containing compounds, as described in US Pat. No. 3,356,658. The copolymers are also crosslinked by the bonded nonwoven products after drying or as the final part of the drying stage self-cures as described in U.S. Patent 3,356,658.

The copolymers useful in this invention can also be from about 1 to about 100 parts by weight a phosphate plasticizer per 100 parts by weight of copolymer, e.g. phosphoric acid derivatives such as triethyl, tributyl, Trioctyl, tri- (2-ethylhexyl), tributoxyethyl, triphenyl, tricresyl phosphate, oresyl, hexyl, 2-ethylbutyl, Octyl-, 2-ethylhexyl-, isooctyl-, nonyl-, üecyl-, 2-butyloctyl, tridecyl, tetradecyl, octadecyl diphenyl phosphate, 2-ethylbutyl, n-octyl, isooctyl, 2-ethyl

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hexyl, nonyl, decyl; 2-n-propylheptyl-, 2-butyloctyl- <, tridecyl-, Tetradecyl, octadecyl dicresyl phosphate, trichloroethyl and tri- (dimethylphenyl) phosphate.

The fire retardant bonded nonwovens of this invention have high tensile strength, good elongation, softness, good handling and flexibility, good draping properties and resistance to common solvents and detergents. With these Properties are the fire retardant bonded nonwovens of this invention for a large number of End uses, many of which have already been mentioned, and others such as cardboard, toweling, Wrapping paper, wallpaper, mats, napkins, tablecloths, heat and sound insulation materials, electrolytic Capacitors, outer skin or layer, and inside of luggage, glue-coated adhesive films, pressure sensitive adhesive films, projection screens, waterproof Wrapping paper, drapery heads, draperies, binders, items for hospitals such as hats, masks, Coats, smocks, trousers, capes, protective covers, washcloths, pillowcases, wipes, locked Tents, filters for food processing, for engines, machines, air systems or liquid systems, electrical insulators, wallpaper, tapes, headrests and armrests for automobiles, upholstered furniture, filled pillows,

109845/1834 ' ^2Ί '

Fiber fillings, sleeping bags, removable covers, bed covers, pillows, curtains, shaders, carpets (Fleece), carpet backing, items of clothing, insulating clothing, underwear, diapers, inserts (collars and cuffs), Car door panels, film backs and car upholstery, etc. are si'nd.

The ethylene / vinyl chloride copolymers which can be used according to this invention are readily made in a variety of ways known to those skilled in the art. The copolymers can be prepared by first adding ethylene and vinyl chloride in an aqueous medium in the presence any suitable anionic or nonionic emulsifier or initiator mixes the suitable free radicals in the chemical Form the mixture at the selected reaction temperatures and pressure conditions. The acrylamide is preferred in aqueous solution either alone or mixed with appropriate amounts of other polar monomers to the Polymerization ethylene and vinyl chloride mixture gradually added during the reaction. The addition of the Acrylamide is preferably started after about 40 to 50 $ of the desired conversion of ethylene and Vinyl chloride was achieved. A pot core latex, in that the polar monomer is concentrated in the outer layers is produced in this way.

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The ethylene / vinyl chloride / acrylic copolymers used in this invention are preferably prepared by a process in which ethylene and vinyl chloride monomers are used in the presence of an alkaline-buffered reduction-oxidation (redox) initiator catalyst system with water and further from about 1 to about 8 wt _o $, based on the monomer feed, or from about to about Tfo, based on the polymer product, an anionic or nonionic emulsifier mixes, wherein has and the emulsifying agent having a hydrophilic balance (HLB) value of about 10 to about 40, the Mixture at a temperature and pressure long enough to cause the polymerization between the ethylene and vinyl chloride and then acrylamide either alone or mixed with other monomers in small amounts in a suitable diluent such as water in the pressurized polymerization reaction mixture of ethylene and vin yl chloride introduces. This process is described in detail in U.S. Patent 3,428,582, which is incorporated herein by reference.

The following examples illustrate the invention. Parts and percentages are by weight "unless otherwise stated.

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example 1

This example explains the production of a 21 / 7Ö / 3 Ethylene / vinyl chloride / acrylamide mixed polymer latex.

Initial loading of the reaction vessel

11.0 g ^K 2 ^S 2 ° 3 ^^ 15.0 g NaHCO ₅
0.8 g of Fe (NO _{3) 3} - 9H ₂ O

1.5 g tetrasodium ethylenediaminetetra _v acetate (NaA)

1.2 g Na lauryl sulfate (NLS)

H ₂ O to make up to 1700 ml

450 g vinyl chloride (VCl)

150 g ethylene (1)

The above constituents are introduced into a suitable reaction vessel and ^{heated to 30 °} C. with stirring, resulting in a reaction pressure of 60 ata. The polymerization is initiated by adding a 1M sodium formaldehyde sulfoxylate NaHS0 ₂ 'CH ₂ 0 ^e 2H ₂ (NFS) / 1.5M ammonium hydroxide (NH.OH) solution, which is added to the mixture at a rate of 5.2 ml / hour adds, at the same time with 18 ml / hour. a 25% NLS solution is added and the pressure is kept constant by adding pure vinyl chloride as required. After 3 hours, a 50% solution of acrylamide in water at 40 ml / hour. admitted. The reaction ends after 5.5 hours and the

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Shunt currents are turned off. A total of 1330 g of VCl, 95 ml of 50% acrylamide, 27 ml of the 1M NFS / l, 5M im ^ OH solution and 92 ml of 25 # Lge JTLS solution are added. The polymer mixture obtained is drained off at the bottom of the autoclave. A total of approximately 3500 g of ethylene / vinyl chloride / acrylamide mixed polymer latex with a content of 4-7 solids and 1.5 ° of sodium lauryl sulfate, based on the weight of the polymer, is obtained. The polymer has a pH of 7-7. The composition of the terpolymer is approximately 21/76/3 ethylene / vinyl chloride / acrylamide.

Example 2

Preweighed samples of Hollingsworth and Vose composite nonwovens containing 75% by weight of cellulose fibers and 25% by weight of nylon fibers are immersed in aqueous dispersions of binder preparations containing an ethylene / vinyl chloride copolymer and an ammonium polyphosphate. The v / äßrigen dispersions contained 13.5 wt _e # Mischpolymerisatfeststoffe and _c 5 Qew.fo ammonium polyphosphate in the crystalline form 1 The impregnated materials are passed through a screen press, weighed, about 2 minutes at a temperature of about 118 ⁰ C dried and re- the bound weighed _s Yliese be through a single nip to flatten zn, calendered and with respect to the ieuerhemmung after ΪΑΡΡΙ Τ4β1

109845/18 34

- 31 -

vertical flammability test examined. The ethylene / vinyl chloride / acrylamide mixed polymer Contained 76% by weight of ethylene, 21% by weight of vinyl chloride and 3% by weight of acrylamide. the Fiber fleece samples had a size of 95 x 209 mm. the The results and further details can be found in the following table.

Tabel

(a)
Ammonium polyphosphate ^{v J}
in the test substance, Hach glimmer
Sec. length of ver
carbonization, cm 0 (comparison) whole sample
consumed whole sample
consumed 4.6 no 8.2 7.6 no 5.7 10.4 no 5.1

(a) based on the fiber weight

- patent claims -

- 32 -

109845/1834

Claims (29)

Patent claims: 1. Fire-retardant, bonded fiber fleece product, characterized by a fiber fleece which is bound by a binder preparation which is an ammonium polyphosphate of the formula ^H ( _n _ _m ) ₊ 2i ^LiH 4) _m ^p _n ⁰ 3n + 1 ' ^{where n is an} integer , which has an average value greater than 10, m / n has an average value between 0.7 and 1.1 and m has an average value equal to n + 2 and contains a copolymer which (i) contains an ethylene / vinyl chloride copolymer with a content of about 5 to about 70 wt. fo ethylene, about 30 to about 95 wt. # vinyl chloride and about 0.1 to about 10 $ by weight. a polar component, namely A) acrylamide and / or B) acrylamide together with at least one additional polar monomer, namely acrylonitrile, methacrylamide, N- (alkyl) acrylamide, N- (hydroxy-substituted alkyl) acrylamide and Έ- (alkyl) methacrylamide with 1 to 3 carbon atoms in each alkyl group, Acrylic acid, methacrylic acid and alkali metal and ammonium salts of acrylic and methacrylic acid, maleic and fumaric acids, itaconic and citraconic acids, half-alkyl esters of maleic, fumaric, itaconic and citraconic acids with 1 to 6 carbon atoms in the alkyl groups, acrylyl and Methacrylyl ester of 109845/18 34 -33- Hydroxyalkanoic acids with 2 to 6 carbon atoms in the alkanoic acids, acrylylamide and methacrylylamide of aminoalkanoic acids with 2 to 6 carbon atoms in the aminoalkanoic acids, hydroxyethyl and hydroxypropyl esters of Acrylic, methacrylic, maleic and fumaric acids, vinyl esters of alkanoic acids with 1 to 6 carbon atoms and alkylsulfonic acid having 1 to 6 carbon atoms, phenylsulfonic acids and acrylyl and methacrylyl esters of hydroxyalkylsulfonic acid with 1 to 6 carbon atoms in the alkyl moieties and / or hydroxyalkylsulfonamides with 1 to 6 Carbon atoms in the hydroxyalkyl moieties; and or (Ii) copolymers of the type described under (i), those treated with an acid or a base having an ionization constant higher than about 10 in amounts up to about $ 100 the amide content of Copolymer are equivalent. 2. Product according to claim 1, characterized in that the average value of η in the ammonium polyphosphate from about 20 to about 400 as determined by the end group titration method. 3. Product according to claim 1, characterized in that that the ammonium polyphosphate is present in amounts of from about 1 to about 30 percent by weight based on the fibers. - 34 109845/1834 4. Product according to claim 1, characterized in, that the ammonium polyphosphate in amounts of about 3 "to about 15 wt. $ based on the fibers is present. 5 » Product according to claim 1, characterized in that the fiber fleece is made from natural fibers» 6. Product according to claim 5, characterized in that that the fibers are cellulose or glass fibers. 7. Product according to claim 1, characterized in that the fiber fleece is made from synthetic fibers. 8. Product according to claim 7 »characterized in that that the fibers are polyester or polyamide fibers. 9 «Product according to claim 1, characterized in that the fiber material is a combination of natural
and synthetic fibers. 10. Product according to claim 1, characterized in that that the nonwoven fabric is in the form of a two-dimensional web. 11. Product according to claim 1, characterized in that that the ethylene / Vinylchloriä-Misohpolymerisat of approximately 183-4 15 to about 70 $ ethylene, from about 30 to about 85 $ vinyl chloride, and from about 0.1 to about 10 $
Contains acrylamide. 12. Product according to claim 1, characterized in that the ethylene / vinyl chloride copolymer of approx 19 to about 23 $ ethylene, from about 74 to about 78 $ vinyl chloride, and from about 2 to about 4 $ acrylamide contains. 13. Product according to claim 1, characterized in, that the binder is a preparation according to (II). 14. Product according to claim 1, characterized in that the polar component of the copolymer is a mixture of acrylamide with an additional polar monomer is. 15. Product according to claim 1, characterized in that the ethylene / yinyl chloride copolymer is a quaternary polymer which is from about 15 to about
70% ethylene, from about 30 to about 85% by weight vinyl chloride, from about 1 to about 5% by weight acrylamide, and from about 0.1 to about 3% by weight bis-hydroxypropyl fumarate. - 36 109845/1834 16. Product according to claim 1 »characterized in that that the nonwoven fabric is a mixture of natural and synthetic fibers and that the ethylene / vinyl chloride mixture polymer of about 15 "to about 70 $ ethylene, contains from about 30 to about 85 $ vinyl chloride and from about 0.1 to about 10 $ acrylamide. | 17 "Product according to claim 16, characterized in that that the natural fibers are cellulose fibers. 18. ■ Product according to claim 17 »characterized in that that the cellulose fibers are wood fibers. 19 · Product according to claim 16, characterized in, that the synthetic fibers are polyamides and polyester fibers. 20. Product according to claim 16, characterized in that that the natural fibers are cellulose fibers and the synthetic fibers are polyamide and polyester fibers. 21. Product according to claim I6, characterized in that that it is a mixture of fibers that is at least 50% by weight Cellulose fibers, polyamide fibers, vinyl acetate fibers, fibers of polymers and copolymers of acrylonitrile, Poly-Cäthyleflglykol-terephthalat) fibers and or mixtures the same contains. 10 9 8 4 5/1834 - 37 - 22. Product according to claim 1, characterized in, that the fiber fleece contains wood fibers and the ethylene / vinyl chloride copolymer from about 15 to about $ 70 ethylene, from about $ 30 to about $ 85 vinyl chloride and contains from about 0.1 to about 10 $ acrylamide. . 23. Product according to claim 1, characterized in that that the ifaservlies a mixture of polyamide fibers and wood fibers and the ethylene / vinyl chloride copolymer is from about 19 to about 23 $ ethylene, from about $ 74 to about $ 78 vinyl chloride and from about $ 2 to Contains approximately $ 4 acrylamide. 24. A method for producing a fire-retardant, bonded nonwoven product, characterized in that . in converting a quantity of fiber in a! non-woven fabric, dispersed a binder formulation in this material, the resulting Materia ^ a ^r J} etnperatur heated sufficiently to cause the flow together and melting the binder in the material, wherein the binder preparation in Claim 1 is defined. 25. The method according to claim 24, characterized in that the binder in the material is thereby di- -38- 103846/1834 It is observed that the material is brought into contact with an aqueous dispersion of the binder preparation. 26. The method according to claim 24 »characterized in that that a fiber fleece is a material in an iOrm one two-dimensional layer or Railway used. fc 27 method according to claim 24, characterized in that bringing the binder into contact with the material in a settling chamber. 29. The method according to claim 24, characterized in that one uses a nonwoven fabric which is a mixture of natural and synthetic fibers and that is used _for an ethylene / vinyl chloride copolymer comprising from about 15 to about 70 $ ethylene, from about 30 to about 85 $ vinyl chloride and from about '0.1 to about 10 $ contains acrylamide. 109845/1834