|Publication number||US3752733 A|
|Publication date||Aug 14, 1973|
|Filing date||Oct 29, 1969|
|Priority date||Oct 29, 1969|
|Also published as||CA940437A, CA940437A1, DE2052926A1, DE2052926B2|
|Publication number||US 3752733 A, US 3752733A, US-A-3752733, US3752733 A, US3752733A|
|Inventors||Graham P, Merchant M, Ottinger A|
|Original Assignee||Monsanto Co|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (31), Classifications (33)|
|External Links: USPTO, USPTO Assignment, Espacenet|
United States Patent Cffice;
Patented Aug. 14, 1973 ABSTRACT OF THE DISCLOSURE Bonded, nonwoven fibrous products bonded with a composition consisting essentially of an ethylene/vinyl chloride interpolymer, containing 5 to 70 percent ethylene,
30 to 95 percent vinyl chloride and 0.1 to percent acrylamide or acrylamide/polar monomer mixtures.
This invention relates to bonded nonwoven fibrous products employing an ethylene/vinyl chloride interpolymer as the bonding agent.
The term nonwoven fibrous material as used herein means a consolidated mass of fibers laid down by mechanical, chemical, pneumatic, electrical or vacuum means, or otherwise deposited, into the desired shape, either flat (webs, mats or sheets) or three-dimensional.
Nonwoven fibrous material can be formed by both a wet process and a dry process. In the wet process, the fibers are slurried in water or similar inert liquid. The slurry is spread on a fiat surface, the inert liquid drained OE, and the Web dried under pressure to form the loosely consolidated mass of randomly-distributed fibers. In the dry process the fibers in the dry state are laid on a solid, fiat surface, for example, a conveyer, by mechanical means or pneumatic means, for example, a carding machine or an air-lay machine. The dry process can be used to lay down the fibers in either a random distribution or an oriented distribution. A thorough discussion of the formation of nonwoven fabrics is presented in Non Woven Fabrics by F. N. Buresh Reinhold Publishing Company, New York, NY. (1962).
Regardless of the method employed to form the nonwoven fibrous material, the material is at this point only a flimsy structure having virtually no tensile strength and is unable to remain as a unitary piece without support. In order that the nonwoven fibrous material possess the necessary tensile strength and cohesion required for practical applications, it is necessary that the fibers be bonded and interlocked in some fashion. The usual and most economical means of accomplishing the bonding and interlocking of the fibers is to impregnate or saturate the nonwoven fibrous material with a bonding agent followed by heating or other means of activation in order to coalesce and fuse the bonding agent, and bond and interlock the fibers.
In many applications, it is essential that bonded nonwoven products exhibit good elongation, resistance to oils and solvents, good drape and hand characteristics, good flame resistance, and non-discoloration, as well as high tensile strength.
Various general purpose synthetic polymers and copolymers have been used as bonding agents for nonwoven fibrous products. Some of the prior art polymers produce undesirably stiff products which are unsuitable for textile use because of poor draping qualities and harsh feel or hand. Other prior art polymers result in discoloration and loss of strength upon exposure to bleach during washing. Still other prior art polymers result in bonded nonwoven fibrous products which exhibit acceptable elongation characteristics, but with a concomitant loss of tensile strength. In general, the bonding agents employed heretofore have not entirely satisfactory.
In accordance with this invention, it has been found that bonded nonwoven fibrous products which exhibit the desirable combination of high tensile strength and elongation, as well as good hand and drape characteristics, are obtained by using an ethylene/vinyl chloride interpolymer as the bonding agent for the nonwoven fibrous material.
The bonded nonwoven fibrous products of this invention can be formed of either natural or synthetic fibers or any combination thereof with the selection of the fiber merely depending upon the specific end use intended for the bonded nonwoven fibrous product. Among the fibers that can be used in accordance with this invention are natural fibers, for example, Wood, jute, sisal, hemp, cotton linters, silk, mohair, cashmere, asbestos and wool, and synthetic fibers, for example, glass, rayon cellulose esters such as cellulose acetate, polyvinyl chloride, polyvinyl acetate, polyacrylonitrile and copolymers thereof, polyethylene, polypropylene and the like, polyesters such as eth'ylene glycol-terephthalate polymers, and polyamides of the nylon type.
In many applications, the bonded nonwoven fibrous products of this invention are prepared from a plurality of natural fibers, or a plurality of synthetic fibers, or a combination of natural and synthetic fibers. Combinations of wood fiber and cotton fiber can be advantageously employed in end products such as shoe liners and the like. In general, the wood fiber comprises the major amount of the fiber content of such bonded nonwoven fibrous products. Combinations of glass fiber and asbestos fiber are generally employed in insulating applications. Combinations of glass fiber and wood fiber are also useful in certain drapery applications. The weight ratio of glass fiber to cellulosic fiber in such bonded nonwoven fibrous products is usually from about 1:10 to about 10: 1.
In wearing apparel applications, a combination of wood fibers and nylon fibers or a combination of wood fibers and rayon fibers can be advantageously employed. Combinations of wood fiber and nylon fiber as well as combinations of wood fiber and polyester fiber are also widely employed in various applications where reinforced sheeting is required. In such combinations of natural and synthetic fibers, the weight ratio of natural fiber to synthetic fiber is generally from about 1:20 to about 20:1 and preferably from about 1:1 to about 3:1.
The nonwoven fibrous materials useful in the preparation of the bonded nonwoven fibrous products of this invention can be prepared by any method known to the art. Thus, the nonwoven fibrous material can be made of fibers deposited in a random manner as well as fibers oriented or aligned along a particular axis. Nonwoven fibrous materials in the form of two-dimensional webs can be prepared by the following methods. Oriented webs are produced using conventional web-style machines, such as openers, pickers, cards, or garnetts. Cross-laid webs are made in a manner similar to oriented webs, except that the fibers are carefully placed at right angles to the machine direction to improve cross-wise strength.
Random webs are produced in air-lay machines, and the nonwoven fibrous material has equal strength in all directions. In the air-lay method, continuous filaments are fed through a cutter or breaker which discharges the fibers into the discharge side of a blower. Suitable conduits are provded to guide the fibers to a collecting screen or airpervious structure for collecting the fibers in the form desired. The screen may be in the form of an endless traveling belt passing through the lower portion of a tower into the upper portion of which the blown fibers are introduced by the conduit. A suction box may be placed beneath the traveling screen to assist in the deposition of the fibers thereon. Instead of using a traveling flat screen, a stationary formed screen may be used. For example, the screen may take the form of a hat shaped cone, such as that used in the felt hat-making industry. Alternatively it may have any other form which is suitable to produce the desired shape of the bonded nonwoven fibrous product such as a rectangular tray. As is the case with the endless traveling belt, suction may also be applied beneath the stationary screen to assist deposition of the fibers thereon.
Random webs are also produced by the direct spray method from a solution or molten mass of the fiber material. This is the conventional procedure for the formation of glass fibers or mineral wool fibers, as well as those of nylon or thermoplastic materials, adapted to be dissolved in a suitable solvent or to be melted. The solution or melt is directed to suitable nozzles or jet-forming orifices and a high pressure fluid stream, such air, nitrogen or steam, is directed against the stream or streams of filament-forming material to disrupt them and coagulate them as fibers in the vicinity of the orifices. Electrostatic spinning methods can also be employed for this purpose. As in the case of the use of blowers, the disrupted and dispersed fibers can be directed to the top of the settling tower and allowed to settle with the aid of suction devices upon a suitable traveling or stationary screen at the bottom of the tower. This procedure is particularly adapted to the production of fibers of siliceous materials such as glass or mineral wool, as well as to thermoplastic resin fibers.
Wet random webs are formed from a slurry of dispersed fiber or paper making or modified paper making machines. Spun-bonded webs are made of randomly oriented continuous filament fibers bonded at the cross-over point. The method includes extrusion of the continuous filament fibers, drawing to orient the fiber, some fiber entanglement by liquids or air, and bonding at the crossover points.
The bonded nonwoven fibrous products of this invention are generally prepared by a method which comprises consolidating the loose fibers into nonwoven fibrous material having the structural configuration of the desired bonded nonwoven fibrous product, dispersing the ethylene/vinyl chloride interpolymer bonding agent within the nonwoven fibrous material, and heating the impregnated nonwoven fibrous material to a temperature sufficient to coalesce and fuse the interpolymer, and optionally heating to a temperature sufiicient to cross-link the interpolymer if a sulfur cross-linking agent is employed.
Another method for the preparation of the bonded nonwoven fibrous products of this invention which is particularly useful when the nonwoven fibrous material is formed by the air-lay method in an air-lay machine comprises contacting the fibers with the ethylene/vinyl chloride interpolymer dispersion or powder as they fall through the settling chamber to their point of deposition. This is advantageously carried out by spraying the ethylene/vinyl chloride interpolymer dispersion or powder into the settling chamber at some intermediate point between the top and the bottom thereof. By spraying the fibers as they descend to the point of collection, it is possible to elfect a thorough distribution of the ethylene/vinyl chloride interpolymer bonding agent among the fibers before they are collected into the nonwoven fibrous material. In the production of certain fibrous products wherein a hot molten mass of a polymer such as nylon or a fused siliceous mass or glass is disrupted by jets of heated air or steam, the bonding agent dispersion or powder can be sprayed directly on the fibers while still hot so that immediately after deposition the bonding agent is set and it bonds and interlocks the fibers in proper relationship.
The interpolymers which are useful in the preparation of the bonded nonwoven fibrous products of this invention generally contain from about 5 to about 70 weight percent ethylene, from about 30 to about 95 weight percent vinyl chloride, and from about 0.1 to about weight percent of a polar monomer component. The polar monomer component can be entirely acrylamide or a portion of the acrylamide can be replaced by one or more polar monomers selected from the group consisting of acrylonitrile, N-(lower alkyl) acrylamide and N-(lower alkyl) methacrylamide containing from 1 to 3 carbon atoms in the lower alkyl groups, N-methylol acrylamide, N[2-(2-methyl-4-oxopentyl)] acrylamide, acrylic acid, methacrylic acid, and alkali metal and ammonium salts of acrylic and methacrylacrylic acids, maleic acid, fumaric acid, half and complete 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 methacrylyl esters of hydroxyalkanoic acids having from 2 to about 6 carbon atoms in the alkanoic acid moieties, acrylylamides and methacrylylamides of aminoalkanoic acids having from 2 to about 6 carbons in the aminoalkanoic acid, hydroxyethyl and hydroxypropyl esters of acrylic, methacrylic, maleic, and fumaric acids, vinyl esters of alkanoic acids having from 1 to 6 carbon atoms such as vinyl acetate, vinyl propionate, and lower alkyl (1 to 6 carbon atoms) sulfonic acid, vinyl esters of phenylsulfonic acids, and alkylphenylsulfonic acids and acrylyl and methacrylyl esters of hydroxyalkylsulfonic acids having from 1 to 6 carbon atoms in said alkyl moieties, and hydroxyalkylsulfonamides, having from 1 to 6 carbon atoms in said hydroxyalkyl moieties. The polar monomer component generally contains at least 50 weight percent acrylamide and preferably at least percent acrylamide.
Thus the interpolymers are at least terpolymers containing ethylene, vinyl chloride and acrylamide and may be a quaternary or higher polymer containing one or more of the above exemplified additional polar monomers in small quantities. Generally such additional polar monomers will not be present in the interpolymer in quantities greater than about 3 percent by Weight.
It is preferred that the interpolymer contain from about 5 percent to about 70 percent ethylene, 30 percent to about percent vinyl chloride, and from about 1 percent to about 5 percent acrylamide. A specific example of choice is a terpolymer containing from about 19 to about 23 percent ethylene, about 74 to about 78 percent vinyl chloride, and from about 2 to about 4 percent acrylamide.
The interpolymers used in accordance with this invention are generally unmodified, but modified interpolymers are also included for use in this invention. The interpolymers are particularly amenable to hydrolytic modification by the use of small quantities of a strongly alkaline material such as an alkali metal hydroxide, or a quaternary ammonium hydroxide such as tetramethyl ammonium hydroxide, or by a strong acid such as the mineral acids, e.g., hydrochloric, sulfuric, phosphoric, nitric. The base or acid used preferably has an ionization constant higher than 10* at 25 C.
The hydrolytic modification is carried out by treating an aqueous dispersion or polymer latex of the ethylene, vinyl chloride, and acrylamide with aqueous base or acid in an amount chemically equivalent to from about 0.1% to about percent of the amide equivalent in the interpolymer.
Specific examples of polar monomers which can be used, as described above, to replace part of the acrylamide in the polar monomer component of the interpolyrner useful in this invention include acrylonitrile, N-methacrylamide, N ethylacrylamide, N propylacrylamide, methacrylamide, acrylic, methacrylic, maleic, fumaric, itaconic, aconitic, and citraconic acids and alkali metal and ammonium salts of such acids, preferably the sodium, potassium or ammonium salts, alkyl esters of such acids, e.g., methyl acrylate, ethylacrylate, butyl acrylate, methyl methacrylate, butyl methacrylate, ethyl methacrylate, monoethyl maleate, dipropyl fumarate, acrylyl 3-hydroxypropionate, methacrylyl hexamide, 2-hydroxyethyl and 2- hydroxypropyl esters of acrylic, methacrylic, maleic, f-umaric, itaconic, aconitic, and citraconic acids, vinyl formate, vinyl acetate, vinyl hexanoate, vinyl and alkyl esters of propanesulfonic acid, vinyl phenylsulfonate, acrylyl and methacrylyl esters of 2-hydroxypropylsulfonic acid, and N-acrylyl and N-methacrylyl 2-hydroxypropanamides.
Illustrative of interpolymers which can be used as bonding agents for the bonded nonwoven fibrous products of this invention are ethylene/vinyl chloride/acrylamide, ethylene/vinyl chloride/hydroxyethylacrylate, ethylene/ vinyl chloride/acrylamide/N isopropylacrylamide, ethylene/vinyl chloride/acrylamidelN-ethylmethacrylamide, ethylene/vinyl chloride/acrylamide/diammonium itaconate, ethylene/vinyl chloride/acrylamide/monobutyl acid maleate, ethylene/vinyl chloride/acrylamide/N methacrylyl propionamide, ethylene/vinyl chloride/acrylamide/ sodium acrylate and ethylene/ vinyl chloride/acrylamide/ sodium methacrylate.
The ethylene/vinyl chloride interpolymer bonding agents can be applied to the fibers of the nonwoven fibrous material by any means known in the art. The ethylene/vinyl chloride interpolymer bonding agents are usually applied to the fibers of the nonwoven fibrous material by application to the surface thereof, or by submersion of the nonwoven fibrous material in a liquid, thickened or foamed dispersion so that the bonding agent penetrates into the interior of the nonwoven fibrous material. Where the nonwoven fibrous material is a two-dimensional fabric in the form of a fleece or web, the ethylene/vinyl chloride interpolymer bonding agents are usually applied in the form of an aqueous dispersion. In a typical application, the fabric is impregnated with the ethylene/vinyl chloride interpolymer bonding agent by dipping or immersing the fabric in the dispersion to provide sufiicient wet pickup of the bonding agent. The wetted, nonwoven fibrous material in the form of a fleece or web can be passed between a pair of pressure rolls to effect substantially uniform impregnation and also to control the amount of the bonding agent applied. The impregnated nonwoven fibrous material is dried by conventional means known to the art in order to remove all or a portion of the water and to effect coalescence and fusion of the ethylene/vinyl chloride interpolymer within the nonwoven fibrous material. The drying temperature and drying time are dependent upon the size, shape and cross-section of the impregnated, nonwoven fibrous material. In general, the drying temperature is controlled so that no appreciable deterioration or degradation of the fibers or the ethylene/vinyl chloride interpolymer occurs.
When the ethylene/vinyl chloride interpolymer bonding agents are used in the form of a dispersion, the dispersion generally contains from about 5% to about 90% of the interpolymer by weight. Such dispersions preferably contain from about to about 60% by weight of interpolymer for ease of application by means of dipping, soaking, spraying and the like.
The amount of ethylene/vinyl chloride interpolymer bonding agent based on the weight of the fiber component of the bonded nonwoven fibrous product can vary widely depending upon the characteristics desired in the final product and the specific end use. The bonded nonwoven fibrous products of this invention generally contain from about 2% to about 200% of interpolymer based on the weight of the fibers. For the production of preforms intended to be converted into shaped articles, it is preferred to employ from about 2% to about 10% of the ethylene/vinyl chloride interpolymer bonding agent based on the weight of the fibers. In the production of insulation materials, the amount of ethylene/vinyl chloride interpolymer bonding agent employed generally falls in the lower part of the above range if the bonding agent is applied primarily adjacent to the surface or surfaces of the product or if it is applied in conjunction with other binders.
When the ethylene/vinyl chloride interpolymer bonding agent is to serve mainly to bond the fibers together to form a bonded nonwoven fibrous product in which the maximum porosity is retained in conjunction with a minimum change of fiber hand and drape characteristics as well as an increase in tensile strength, there is preferably employed from about 10% to about 70% by weight of bonding agent solids based on fiber content. The lower portion of this range generally gives the maximum porosity and provides a minimum change in the fiber hand and drape characteristics although in the higher portion of this range porosity is mainly retained and the fiber hand and drape characteristics are still evident. The bonded nonwoven fibrous products thus obtained are advantageously used for many sanitary purposes, such as table napkins, bibs, tablecloths, sanitary napkin covers, disposable diapers, disposable sheets, and surgical dressings and compresses. When this amount of bonding agent is used there is relatively little or no window paning i.e., the interstices between fibers are left open leaving a highly porous bulky product. If desired, the density of the product can be modified by the application of various amounts of pressure prior to, or in many cases, after the saturated nonwoven fibrous material has been heated for bonding.
Bonded nonwoven fibrous products containing from about 40% to about 150% by weight of ethylene/vinyl chloride interpolymer bonding agent based on the weight of the fiber generally find use in the garment industry to provide interlining fabrics for coats, dresses, collars, cuffs, and the like, and to provide outer wearing apparel fabrics, such as blouses, skirts, shirts, dresses, and the like. Bonded nonwoven fibrous products containing the bonding agent in this range are also useful as curtain and drapery materials. In addition to the general household and apparel uses mentioned above, the bonded nonwoven fibrous products of this invention in which 10% to by weight of bonding agent based on the weight of fiber is employed find many light industrial uses as wiping cloths, filters and lining materials for packaging.
Bonded nonwoven fibrous products of the present invention which contain from about 100% to about 200% by weight of the bonding agent based on the weight of the fiber are particularly useful for heavy industrial uses where durability and resistance to wear are desired. Such uses include industrial gaskets, packings, filters, and the like.
If desired, the aqueous dispersion of ethylene/vinyl chloride interpolymer can also contain a wetting agent to assist penetration of the nonwoven fibrous material to which it is applied. The aqueous dispersions can also contain a foaming agent or they can contain a defoamer when the ingredients of the aqueous dispersion have a tendency to give rise to foaming and when such foaming is undesirable. The conventional wetting agents such as the sodium salt of dioctylsuccinic acid can be used and the conventional foaming and defoaming agents can be employed such as sodium soaps including sodium oleate for foaming and octyl alcohol or certain silicone antifoaming agents for defoaming.
In some instances, the properties of bonded nonwoven fibrous products are greatly enhanced by a heat cure of the interpolymer to effect cross-linking. Ethylene/vinyl chloride interpolymers can be cross-linked with various sulfur containing compounds as is disclosed in United States Patent No. 3,356,658. The interpolymers are crosslinked by subjecting the bonded nonwoven fibrous product, after the drying operation, or as a final portion of the drying stage itself, to a curing operation as disclosed in US. 3,356,658.
The bonded nonwoven fibrous products of this invention are characterized by high tensile strength, good elongat on, softness, good hand and flexibility, good drape and resistance to many common solvents and detergents. With these properties, the bonded nonwoven fibrous products of this invention are suitable for use in a wide variety of end applications, many of which have been noted above and including, for example, paper board, toilet tissues,
cleansing tissues, toweling, wrappings for food products, tea bags, wallpaper, mats, napkins, table cloths, heat or sound insulating materials, electrolytic condensers, luggage skin and interiors, glue coated tape stocks, pressure sensitive tape stocks, masking sheets, pennants, banners, labels, book cover stocks, projection screens, gaskets, printing press top cover sheets, waterproof wrapping paper, sandpaper backs, printing tape, drapery headers, draperies, binders, hospital items such as caps, masks, gowns, jackets, scrub pants, capes, shoe covers, wash cloths, pillow cases, wipes, bandages, alcohol preps, surgical dressings, napkins, cubicle curtains, drapes, diapers and sheets, filters for food processing, motors, machines, air systems or liquid systems, electrical insulators, tapes, ribbons, automobile head and arm rests, upholstery, stuffed pillows, fiberfills, sleeping bags, slip covers, bed spreads, blankets, curtains, window shades, carpeting (nonwoven), carpet backing, wearing apparel, clothing insulation, underwear, diapers, interfacing and interliners (collars and culfs), inner soles for shoes, automotive door panels, film backings, floor cleaner pads, abrasive pads, artificial leather and chamois, micro polishers for metals and optical lenses, overlays for plastics, battery separators, automotive speakers, polishers, decorations and automotive padding.
The ethylene/vinyl chloride interpolymer bonding agents have been described as the sole bonding agent for the bonded nonwoven fibrous products of this invention. However, for some applications, the interpolymers can be employed in combination with thermosetting, precondensate resins, such as aminoplasts, which are capable of cooperating with the ethylene/vinyl chloride interpolymer bonding agents to give enhanced properties of launderability and dry cleaning resistance to the bonded nonwoven fibrous products, particularly when they are in the form of fabric material. The preferred aminoplast resins for blending with the ethylene/vinyl chloride interpolymers are the condensation products or pre-condensates of urea and formaldehyde, ethylene, urea and formaldehyde, and of formaldehyde and melamine including alkalated, pre-condensates of urea formaldehyde and melamine formaldehyde. Typical of these aminoplasts are the reaction products of formaldehyde and triazines, such as melamine and the alcohol modified melamine formaldehyde condensates which have been etherified by reaction with a lower alcohol, such as methyl or ethyl alcohol.
Where an auxiliary bonding agent is employed with the ethylene/vinyl chloride interpolymers, it can be used in amounts up to about 50% by weight, based on the weight of the ethylene/vinyl chloride interpolymer bonding agent, with about to by weight of the aminoplast being preferably employed.
The ethylene/vinyl chloride interpolymers useful in this invention are readily prepared by various means well known to the art. The interpolymers can be prepared by first mixing ethylene and vinyl chloride in an aqueous medium in the presence of any suitable anionic or nonionic emulsifier and any initiator capable of generating free radicals in the chemical mixture at the chosen reaction temperature and pressure. The acrylamide, preferably in aqueous solution either alone or mixed with the appropriate amounts of other polar monomers, is added to the polymerizing ethylene and vinyl chloride mixture gradually throughout the reaction. The addition of the acrylamide is preferably begun after about 40 to 50 percent of the desired conversion of the ethylene and vinyl chloride has been reached. A shell-core latex in which the polar monomer is concentrated in the outer layers is produced.
The ethylene/vinyl chloride/acrylamide interpolymers used in this invention are preferably prepared by a process which comprises mixing ethylene and vinyl chloride monomers in the presence of an alkaline buffered reductionoxidation (redox) initiator-catalyst system, water, and from about 1 percent to about 8 percent by weight based upon the monomer feed, or from about 4 percent to about 7 percent based upon the polymer product of an anionic or non-ionic emulsifying agent having a hydrophilic-lipophilic balance (HLB) value of from about 10 to about 40, and reacting the mixture at a temperature and pressure and for a time sufficient to cause polymerization between the ethylene and vinyl chloride, and then to introduce acrylamide, either alone, or mixed with other monomers in minor amounts in an appropriate diluent such as water into the pressurized polymerizing reaction mixture of the ethylene and vinyl chloride. This process is described in detail in US. Pat. 3,428,582 and the subject matter thereof is expressly incorporated herein by reference. Ethylene/vinyl chloride latices prepared by this process have particles sizes of emulsified interpolymer from about 500 to 5000 angstroms, preferably from about 1000 to about 2000 angstroms.
The following examples will illustrate this invention. Parts and percent are by weight unless otherwise indicated.
EXAMPLE 1 This example illustrates the preparation of a 21/76/3 ethylene/vinyl chloride/acrylamide interpolymer latex.
Reaction vessel initial charge G. K S O (KPS) 11.0 NaHCO 15.0 Fe(NO -9H O 0.8 Tetrasodium ethylenediaminetetraacetate (Na EDTA) 1.5 Na lauryl sulfate (SLS) 1.2 H 0 to make 1700 ml. Vinyl chloride (VCl) 450 Ethylene (E) 150 The above ingredients are charged to a suitable reaction vessel and heated to 30 C. with stirring to give a reaction pressure of 850 p.s.i.g. Polymerization is started by adding a l M sodium formaldehyde sulfoxylate- NaHSO -CH O-2H (SFS) /1.5 M
ammonium hydroxide (NH OH) solution to the mixture at a rate of 5.2 ml./hr. at the same time 18 ml./hr. of a 25 percent SLS solution is added and the pressure is kept constant by the addition of pure vinyl chloride as required. After three hours, a 50 percent solution of acrylamide in water solution is added at 40 ml./hr. The reaction steps after 5.5 hours and the feed streams are turned off. A total of 1330 g. of VCl, 95 ml. of the 50 percent acrylamide, 27 ml. of the l M SFS/1.5 M NH OH solution, and 92 ml. of the 25 percent SLS solution are added. The resulting polymer latex is vented out the bottom of the autoclave. A total of about 3500 g. of the ethylene/ vinyl chloride/acrylamide polymer latex is obtained containing 47 percent total solids, and 1.5 percent sodium lauryl sulfate (based on the weight of the polymer). It has a pH of 7.7 The composition of the terpolymer is about 21/76/3 ethylene/vinyl chloride/acrylamide.
EXAMPLE 2 Preweighed samples of Hollingsworth and Vose nonwoven fabric composite comprising weight percent cellulosic fiber and 25 weight percent nylon fiber are immersed in aqueous dispersions of ethylene/vinyl chloride interpolymer bonding agents. The aqueous dispersions contain 13.5 weight percent interpolymer solids. The impregnated fabrics are passed through a size press, weighed, dried for about two minutes at a temperature of about 118 C. and weighed. The bonded nonwoven fabrics are subjected to calendering through a single nip for smoothness and tested for hand and drape characteristics and tensile strength. Hand and drape characteristics are determined qualitatively by touch and results are given on a scale of 1 through 10. Number 1 means very soft and highly flexible. Number 10 means very rough and non-flexible. Tensile strength is determined by TAPPI T40403-6l with a table model Instron. Results and further details are given in the table below Where the amount of bonding agent in the bonded nonwoven fabric is given in percent by dry weight based on the weight of the nonwoven fabric, tensile strength is given in lb./in. width, and the following abbreviations are used in order to simplify tabular identification of the monomers.
TABLE Bonding agent in nonwoven fabric Hand and Tensile drape Strength Bonding agent, percent composition VCl The embodiments of this invention in which a particular property or privilege is claimed are defined as follows:
1. Bonded nonwoven fibrous product comprising nonwoven fibrous material bonded with a bonding agent consisting essentially of a composition selected from the group consisting of (I) an ethylene/vinyl chloride interpolymer containing from about to about 70 weight percent ethylene, from about 30 to about 95 weight per cent vinyl chloride, and from about 0.1 to about Weight percent of a polar component selected from the group consisting of (A) acrylamide, and
(B) acrylamide in combination with at least one additional polar monomer selected from the group consisting of acrylonitrile, N-(alkyl) acrylamide, having from 1 to 3 carbon atoms in said alkyl groups, methacrylamide, N-(alkyl) methacrylamide, having from 1 to 3 carbon atoms in said alkyl groups, N- methylol acrylamide, N[2-(2-methyl-4-oxopentyl)] acrylamide, 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 having from 1 to 6 carbon atoms in said alkyl groups, acrylyl and methacrylyl esters of hydroxyalkanoic acids having from 2 to 6 carbon atoms in said alkanoic acids, acrylylamide and methacrylylamides of aminoalkanoic acids having from 2 to 6 carbon atoms in said aminoalkanoic acid, hydroxyethyl and hydroxypropyl esters of acrylic, methacrylic, maleic, and fumaric acids, vinyl esters of alkanoic acids having from 1 to 6 carbon atoms and alkyl sulfonic acid having from 1 to 6 carbon atoms, phenylsulfonic acids, and acrylyl and methacrylyl esters of hydroxyalkylsulfonic acid having from 1 to 6 carbon atoms in said alkyl moieties, and hydroxyalkyl-sulfonamides, having from 1 to 6 carbon atoms in said hydroxaylkyl moieties; and (II) interpolymers of the type described in (I) treated with an acid or a base having an ionization constant higher than about 10- in amounts equivalent to up to about 100 percent of the amide content of said interpolymer, said interpolymer having a particle size of from aobut 500 to 5000 angstroms.
2. Product of claim 1 wherein the nonwoven fibrous material is made of natural fibers.
3. Product of claim 2 wherein the fibers are cellulosic fibers.
4. Product of claim 1 wherein the nonwoven fibrous material is made of synthetic fibers.
5. Product of claim 4 wherein the fibers are polyester fibers or polyamide fibers or glass fibers.
6. Product of claim 1 wherein the nonwoven fibrous material is a combination of natural fiber and synthetic fiber. 7. Product of claim 1 wherein the nonwoven fibrous material is in the form of a two-dimensional web.
8. Product of claim 1 wherein the ethylene/vinyl chloride interpolymer contains from about 15 to about 70 percent ethylene, from about 30 to about percent vinyl/ chloride and from about 0.1 to about 10 percent acrylamide.
9. Product of claim 1 wherein the ethylene/vinyl chloride interpolymer contains from about 19 to about 23 percent ethylene, from about 74 to about 78 percent vinyl chloride, and from about 2 to about 4 percent acrylamide.
10. Product of claim 1 wherein the bonding agent is (II).
11. Product of claim 1 wherein the polar component of the interpolymer comprises acrylamide and an additional polar monomer.
12. Product of claim 1 wherein the ethylene/vinyl chloride interpolymer is a quaternary polymer containing from about 15 to about 70% ethylene, from about 30 to about 85 weight percent vinyl chloride, from about 1% to about 5% acrylamide, and from about 0.1 to about 3% by weight of bis-hydroxypropyl fumarate.
13. Product of claim 1 wherein the nonwoven fibrous material is a combination of natural and synthetic fibers and the ethylene/vinyl chloride interpolymer contains from about 15 to about 70 percent ethylene, from about 30 to about 85 percent vinyl chloride, and from about 0.1 to about 10 percent acrylamide.
14. Product of claim 13 wherein the natural fibers are cellulosic fibers.
15. Product of claim 14 wherein the cellulosic fibers are wood fibers.
16. Product of claim 13 wherein the synthetic fibers are polyamides or polyesters.
17. Product of claim 13 wherein the natural fibers are cellulosic fibers and the synthetic fibers are polyamides or polyesters.
18. Product of claim 13 wherein the combination of fibers comprises at least 50% by weight of fibers selected from the group consisting of cellulosic fibers, polyamide fibers, vinyl acetate fibers, fibers of polymers and copolymers of acrylonitrile, poly-(ethylene iglycol-tereph thalate) fibers and mixtures thereof.
19. Product of claim 1 wherein the nonwoven fibrous material is composed of wood fibers and the ethylene/ vinyl chloride interpolymer contains from about 15 to about 70 percent ethylene, from about 30' to about 85 percent vinyl chloride, and from about 0.1 to about 10 percent acrylamide.
20. Product of claim 1 wherein the nonwoven fibrous material isa combination of polyamide fibers and wood fibers and the ethylene/vinyl chloride interpolymer contains from about 19 to about 23 percent ethylene, from about 74 to about 78 percent vinyl chloride, and from about 2 to about 4 percent acrylamide.
21. Product of claim 11 wherein the additional polar monomer is N-methylol acrylamide.
22. Product of claim 1 wherein the nonwoven fibrous material is a combination of natural and synthetic fibers and the ethylene/vinyl chloride interpolymer contains from about 15 to about 70 percent ethylene, from about 30 to about 85 percent vinyl chloride and from about 0.1 to about 10 percent of an additional polar component comprising acrylamide and N-methylol acrylamide.
23. Product of claim 1 wherein the bonding agent composition is present in an amount from about 2% by weight 1 1 1 2 to about 200% by weight based on the weight of the non- 3,428,582 2/1969 Des Deex 117155 woven fibrous material. 3,120,449 2/ 1964 Griswold 117-140 References Cited GEORGE F. LESMES, Primary Examiner UNITED STATES PATENTS 5 W. R. DIXON, JR., Assistant Examiner 3,231,533 1/1966 Garrett et a1 l17-140 3,352,710 11/1967 Wolf et a1. 117-140 3,380,851 4/1968 Lindemanns et a1. 117-140 117140 A, 156-62.2, 30S; l62-164
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|U.S. Classification||524/13, 162/164.6, 162/168.3, 524/555, 156/62.2, 162/164.1, 156/305|
|International Classification||D21H17/37, D21H17/00, C09J127/00, D04H1/58, C08F214/06, D21H17/34, D21H17/43, C09J127/04, D21H17/35, C08F214/00, D21H17/45, C08F14/00, D04H1/64, C08F210/00|
|Cooperative Classification||D21H17/37, D21H17/43, D04H1/641, D21H17/455, D21H17/34, D21H17/35|
|European Classification||D04H1/64A, D21H17/45B, D21H17/34, D21H17/35, D21H17/43, D21H17/37|