DK142177B - Bonded nonwoven fibrous material and terpolymer to make them. - Google Patents

Description

(11) PUBLICATION NOTICE 1 ^ 2177 (W) \ pB.y DENMARK c os f 2ii / 06 '(21) Application No 5 ^ 95/71 (22) Filed on 15 · Jul' 1971 (24) Running Day 15 · Jul . 1971 (44) The application presented and 1 n fine petition published on 15 * S®P · 1 9 ^^

DIRECTORATE OF

PATENT AND TRADE MARKET <3 °) Priority requested from it

Jul 16 1970, 55615 US

Jul 20 1970, 56685, US

(71) AIR PRODUCTS AND CHEMICALS INC., Box 558, Allentown, Pennsylvania T8105, US.

(72) Inventor! William Franklin J? Allwell Jr., 16 Roclare Lane, St. Louis, Missouri 65151, US.

(74) Plenipotentiary in the proceedings:

The patent agent company Magnus Jensens Eftf._ (54) Tied nonwoven fibrous material and terpolymer for their manufacture.

The invention relates to a bonded nonwoven fibrous material as further specified in the preamble of claim 1 and a terpolymer specified in the preamble of claim 2 for use in preparing the bonded nonwoven material containing units of ethylene and JT-methylol aerylamide, hereinafter also referred to as E and NMA, respectively, for their preparation *

The term "nonwoven fibrous material" here means a continuous mass of fibers which, by mechanical, chemical, pneumatic, electrical or vacuum means, or otherwise deposited into a desired shape which may be planar, e.g. a web, a mat or a sheet, or three-dimensional.

The material of the invention is peculiar to the characterizing part of claim 1 and the terpolymer of the invention is peculiar to the characterizing part of claim 2. The present stable E-VCl-NMA terpolymer usually has a particle size as emulsion interpolymer of 500-150 ° C and a molecular weight of 25000-150000 measured by intrinsic viscosity or gel permeation chromatography. The terpolymer can be used in the form of a latex or as an organic solution after coagulation with alcohols such as methyl alcohol and ethyl alcohol. the clay polymers are soluble in organic solvents such as dimethylformamide, tetrahydrofuran and dimethylacetamide.

Patent U.S. Patent No. 3,459,698 discloses bonded nonwoven fibrous articles, the binder being ethylene-U-methylolacrylamide - acrylic acid tripolymers, and from Danish Patent Application No. 1845/69 coating of a fibrous material with an ethylene-vinyl chloride is known. acrylamide terpolymer in which a portion of the acrylamide may be replaced by H-methylolaerylamide.

The advantages of using pure N-methylolacrylamide instead of a mixture with acrylamide is that H-methylolacrylamide gives fibrous nonwoven products greater resistance to washing and greater strength than acrylamide, as the methyl group results in greater cross-linking ability.

Furthermore, triple polymers with ethylene-vinyl chloride-U-methylolacrylamide binders are easier to formulate because H-methylolacryl amide is available directly as a solution rather than as a solid; and increased stability - less sedimentation from the solution - is achieved when the acrylamide is completely replaced.

The terpolymer can be prepared in various known ways.

It 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 producing free radicals in the chemical mixture at the selected reaction temperature. and the selected print. H-methylolacrylamide, preferably in aqueous solution, is gradually added to the polymerizing ethylene and vinyl chloride mixture throughout the reaction. The addition of the H-methylolacrylamide is preferably started after 40-50 $ of the desired conversion of the ethylene and vinyl chloride has occurred. A polymeric latex polymer latex structure is formed where the units of the polar monomer are concentrated in the outermost layer.

The terpolymer is preferably prepared by a process consisting of mixing the ethylene and vinyl chloride monomer in the presence of an alkaline buffer equipped with oxidation (redox) initiator (redox) catalyst system, water and 1-4 the polymer product of an anionic emulsifier and reacting the mixture at a temperature and pressure and for a time sufficient to effect polymerization between the ethylene and vinyl chloride and then introducing N-methylolaeryl amide in a suitable diluent such as water in the pressurized polymerization reaction mixture of the ethylene and vinyl chloride. This process is described in detail in U.S. Patent No. 3,428,582.

Examples 1-3 below illustrate the preparation of terpolymer of the invention, while Example 4 illustrates the use of these terpolymers for impregnating nonwoven materials. Parts and percentages are by weight unless otherwise stated '

Example 1.

This example illustrates the preparation of a 20 * 76 * 4-ethylene-vinyl chloride-N-methylolacrylamide blend polymer latex.

Initial arch in reaction vessel.

14 g K 2 S 2 ° 3 (KPS) 14 g NaHCO 3 10 ml Pedro), 9H 2 O (0.2 M) tetrasodium methylenediamine tetraacetate (Na 2 EDTA) (0.4 M) 1.5 g Na-lauryl sulfate (SL3)

HgO al 1540 ml methyl alcohol 160 ml 720 g vinyl chloride (VCl) 575 g ethylene (E)

The above ingredients are placed in a suitable reaction vessel and heated to 30 ° C with stirring to obtain a reaction pressure of 126 kg / cm · The polymerization is started by adding a 15 # fs SPS / 1.5 M NH 2 OH solution where SPS denotes sodium formaldehyde sulf oxy lat or NaHSOgCHgO 2 Hg, to the mixture at a rate of 3 ml per ml. hour. At the same time add 20 ml per ml. hour of a 25 # SLS solution in the first hour and the pressure is kept constant by the addition of pure vinyl chloride as needed. After 1 hour, a 40 # solution of N-methylolacrylamide and a 9.7 $ Na-lauryl sulfate solution are added at the same time at a rate of 60 ml per hour. The reaction is stopped after 4.5 hours when 610 g of VCl is added and the feed streams are stopped. A total of 1330 g of VCl, 155 ml of 40 # N-methylolacrylamide, 194 ml of 15 $ SPS / 1.5 M NH 2 OH solution and 20 ml of 25 # SLS solution were added. The resulting polymer latex is removed through the bottom of the autoclave. A total of approx. 3250 g of ethylene-vinyl chloride-N-methylolacrylamide polymer latex containing $ 48.8 total dry solids and sodium lauryl sulfate (based on the weight of the polymer). The product has a pH 4 142177 of 8.6 and a molecular weight of 77,000. The composition of the terpolymer is about 20; 76; 4 ethylene-vinyl chloride-N-methylolacrylamide.

Example 2.

An aqueous dispersion of 20: 76: 4-ethylene-vinyl chloride-N-methylolacrylamide terpolymer prepared according to Example 1 and containing ca. 45% by weight of polymer solids is coagulated with isopropanol. The terpolymer is washed with water and dried.

Example 3

Terpolymers of the following composition are prepared according to the procedure of Example 1.

Composition Particle size, Å Average T ° C

_______________ molecular weight s EACl / MA.

19.5 / 78 / 2.2 - 18.5 21/75/4 981 + 152 58,700 11.5 20/76/4 866 + 108 77,000 13.5 21.5 / 75 / 5.5 1111 ± 133 59,000 6.5

The emulsions of Examples 1-3 xan are used to impregnate nonwoven fabric in an amount of 60% by weight to improve e.g. lining material for coats, jackets and other clothing.

The resulting nonwoven fabrics have excellent solvent resistance and good grip.

The bonded nonwoven fibrous products of the invention may be formed from either natural or synthetic fibers, as set forth in the preamble of claim 1, the choice of fiber being dependent upon the purpose for which the finished bonded nonwoven fibrous product is to be used.

For many applications, the bonded non-woven fabrics of the present invention are made from a number of natural fibers or a number of synthetic fibers or a combination of natural and synthetic fibers. Combinations of wood fibers and cotton fibers may advantageously be used in the final product, f. For example, for shoe liners and the like, usually the wood fibers comprise a predominant amount of fiber content of such bonded nonwoven fibrous products. Glass fibers are normally used for insulation purposes. Nonwoven fibrous products are usually from 1:10 to 10: 1.

142177 5

When used for garments, a combination of wood fibers and nylon fibers or a combination of wood fibers and rayon fibers may be advantageous. Combinations of wood fibers and nylon fibers as well as combinations of wood fibers and polyester fibers are also widely used for various purposes, where reinforced sheets are desired. In such combinations of natural and synthetic fibers, the weight ratio of natural fibers to synthetic fibers is usually from 1:20 to 20: 1 and preferably from 1: 1 to 3: 1.

The nonwoven fibrous materials suitable for the manufacture of bonded nonwoven fibrous products according to the invention can be made in any known manner. Thus, the nonwoven fibrous material can be made of randomly derived fibers as well as fibers oriented along parallel axes. Nonwoven fibrous materials in the form of two-dimensional sheet webs can be made by the following methods: Oriented webs are prepared using simple machines for this purpose such as openers and cards, Cross-lined webs are prepared in a similar manner to oriented webs, but with the difference that the fibers are carefully placed at a right angle to the direction of the machine to improve the transverse strength.

Random orientation webs are manufactured in air deposition machines and the nonwoven fibrous material has the same strength in all directions. In the air deposition method, continuous filaments are supplied through a cutting or breaking apparatus which delivers the fibers to a blower. By means of suitable wires, the fibers are fed to a joint screen or an air-permeable carrier to assemble the fibers in the desired shape. The screen may take the form of an endless moving belt which passes through the lower part of a tower into which the upper part of the fibers is inserted by means of the cord. There may be a suction box under the moving screen which assists in the deposition of the fibers thereon. Instead of using a moving flat screen, a shaped stationary screen can also be used.

Eg. For example, the sieve may be shaped like a hat-shaped cone like the one used in the felt hat fabrication. Alternatively, it may have any other shape suitable for producing the desired configuration of the bonded nonwoven fibrous product, for example * a rectangular tray. just as in the case of the endless moving belt, suction may be provided under the stationary screen to promote the deposition of the fibers thereon.

Randomly oriented webs can also be produced by the direct spraying method, namely by spraying from a solution or a melted mass of the fibrous material. This is the usual process for forming glass fibers or mineral wool fibers, as well as fibers of nylon or thermoplastic materials, which are suitable for dissolving in a suitable solvent or for melting. The solution or melt is directed to nozzles or beam-forming orifices, and a high-pressure fluid stream, e.g., air, nitrogen or water vapor, is directed to the stream of all filament-forming streams for breaking and coagulating them as fibers near the orifices. Electrostatic spinning methods can also be used for this purpose, just as in the case of blowers, the broken and dispersed fibers can be directed to the top of a deposition tower and allowed to be deposited by suction means on a suitably moved or stationary screen on the bottom of the tower. This process is particularly suitable for the production of fibers of silica containing materials such as glass or mineral wool and for thermoplastic resin fibers.

Wet-formed webs with random: fiber orientation are prepared from a slurry of dispersed fibers on possibly modified paper-making machines. Spunbond fibers are made from randomly oriented continuous filament fibers which are bonded at the junction points. The method comprises extrusion of the continuous filament fibers, stretching to orient the fibers, and obtaining any fiber entanglement by liquids or air and bonding at the junctions.

The bonded nonwoven fibrous products of the invention are usually prepared by a method which comprises consolidating the loose fibers in the nonwoven fibrous material with the structural configuration of the desired bonded nonwoven fibrous product, dispersing E / VCl / NM the blend polymer binder in the nonwoven fibrous material and heating the impregnated nonwoven fibrous material to a temperature sufficient for forming and melting the blend polymer, then optionally heating to a temperature sufficient for crosslinking the blending polymer , if a sulfur-containing crosslinking agent is used.

Another method of preparing the bonded nonwoven fibrous products of the invention, which is particularly suitable when the nonwoven fibrous material is formed by the air deposition method of an air deposition machine, comprises providing a cone between the fibers and E / VCl / The NMA terpolymer dispersion or powder as they fall through the deposition chamber to the lower point. This procedure is advantageously performed by spraying the E / VCl / NMA blend polymer dispersion or powder into the deposition chamber at an intermediate point between the top and bottom thereof.

By spraying the fibers, as they move downward to the assembly point, it is possible to perform a pervasive distribution of the E / VC1 / NMA terpolymer bonding agent among the fibers before assembling them into the nonwoven fibrous material. In the manufacture of certain fibrous products where a hot molten mass of a polymer such as nylon or molten silicic acid or glass is interrupted by jets of heated air or water vapor, the binder dispersion or powder can be sprayed directly onto the fibers in an even hot state so that immediately after deposition, the binder is cured and bonded, locking the fibers in the correct position. Still other methods include adding the E / VCl / MA terpolymer to the fibers prior to consolidation, e.g. by adding the E / Yci / MA terpolymer to the aqueous fiber solution in a modified papermaking process.

The E / VCl / HMA binders can be applied to the fibers of the nonwoven fibrous material by any known means. The E / VCl / NMA binders can normally be applied to the fibers of the nonwoven fibrous material by application to the surface thereof or by immersing the nonwoven fibrous material in a liquid, thickened or foamed dispersion to allow the binder to penetrate. the interior of the nonwoven fibrous material. Where the nonwoven fibrous material is a two-dimensional fabric in the form of a web or web, the E / VCl / NMA binder is usually applied in the form of an aqueous dispersion. In a typical application, the fabric is impregnated with the E / VCl / NMA blending agent by immersing the fabric in the dispersion to provide sufficient wet absorption of the binder. The wetted nonwoven fibrous material in the form of a web or web can be passed between a pair of pressure rollers to achieve a practically uniform impregnation and also to control the amount of binder applied. The impregnated nonwoven fibrous material is commonly dried to remove all or part of the water and to effect a compound and melting of E / VCl / NMA-t is the polymer in the nonwoven fibrous material. The drying temperature and drying time depend on the size, shape and cross-section of the impregnated Nonwoven fibrous material. Normally, the drying temperature is adjusted so that no significant degradation or degradation of the fibers occurs in the E / VCl / HMi terpolymer. The hair E / VCl / HMA binder agents are used in the form of a dispersion, the dispersion usually contains 5-90% by weight terpolymer. Such dispersions preferably contain 10-60% by weight of blend polymer for convenient application by dipping, soaking, spraying or the like.

The amount of E / VCl / HM bond, however, based on the weight of the fiber component of the bonded nonwoven fibrous product, may vary within wide limits depending on the characteristics desired by the final product and the use one wishes to make. thereof. The bonded nonwoven fibrous products of the invention usually contain 2-200 $ blend polymer based on the weight of the fibers. For the preparation of preproducts which are intended to be converted into shaped articles, it is preferred to use 2-10 $ E / VCl / HMa binder based on the weight of the fibers. In the manufacture of insulating materials, the amount of E / VCl / UMA binder usually falls at the low end of the above range if the binder is first applied near the surface or surfaces of the product or if applied in conjunction with other binders.

The hair E / VCl / MMA binder essentially serves to bond the fibers to form a bonded nonwoven fibrous product which has retained maximum porosity in connection with minimal change in the grip and fall of the fibers and in connection with an increase in tensile strength. , preferably 10-70% by weight of binder solids based on the fiber content is used. One bottom end of this range usually provides maximum porosity and minimal changes in the grip and fall of the fibers, although the porosity is generally maintained at the upper end of this range, just as the grip and fall of the fibers still clearly appear. Non-woven fibrous products thus made are advantageously used for many sanitary purposes, for example, such as napkins, bibs, tablecloths, sanitary napkins, disposable diapers, disposable fabrics and surgical dressings and compresses. When such a large amount of binder is used, relatively few "windows" remain in the pattern, which means that the spaces between the fibers have remained open, giving a highly porous and voluminous product. If desired, the density of the product can be modified by applying different pressure before or in many cases after the saturated nonwoven fibrous material has been heated for bonding.

Bonded nonwoven fibrous products containing 40-150% by weight of E / VCl / tTMA bond based on the weight of the fibers are usually used in the garment industry for the manufacture of lining fabrics for coats, habits, flips, cuffs and the like and for the manufacture of outer garments such as blouses, skirts, shirts, dresses and the like. Bonded nonwoven fibrous products containing the binder in this area are also suitable for rugs and upholstery materials. In addition to being used for the above-mentioned household and clothing purposes, the bonded nonwoven fibrous products of the invention, which contain 10-100 weight percent binder based on the weight of the fibers, can be used for many other purposes, such as for cloths, filters and lining materials. for packaging.

Bonded nonwoven fibrous products of the invention which contain 100-200 weight percent binder based on the weight of the fibers are particularly suitable for use in the industry where durability and durability are required. Such applications are, for example, industrial gaskets and filters.

If desired, the aqueous E / Cl / ftMA dispersion may also contain a wetting agent to facilitate penetration into the nonwoven fibrous material to which the dispersion is applied. The aqueous dispersions may also contain a foaming agent or they may contain an antifoaming agent when the components of the aqueous dispersion tend to induce foaming and when such foaming is undesirable. Common wetting agents such as the sodium salt of dioctyl succinic acid may be used and may be used. common foaming agents and anti-foaming agents such as sodium soaps including sodium oleate for foaming and octyl alcohol or certain silicone antifoaming agents for foaming.

Example 4

Already weighed samples of a Nonwoven Fabric (Hollingsworth and Vose) consisting of 75% by weight cellulose fibers and 25% by weight nylon fibers are immersed in aqueous dispersions of E / VC1 / NMA binders. The aqueous dispersions contain 15.5% by weight of blend polymer solids. The impregnated fabrics are passed through an finishing press, weighed and dried for approx. 2 minutes at about, 118 ° C and weighed again. The bonded nonwoven fabrics are calendered through a single pair of rollers to achieve smoothness and examined for grip and fall, toughness and tensile strength. The properties of grip and fall are determined qualitatively by emotion, and the results are evaluated on a scale of 1 to 10 points, 1 point means very soft and very flexible, while 10 points means very rough and difficult to bend. The tensile strength is determined according to the TAPPI T404 OS-61 using a table of the "Instron" model. The toughness is determined by measuring the area under a curve in a tensile diagram. Results and further details are shown in the table below, where the amount of binder in the bonded nonwoven is given in percent dry matter on the basis of the weight of the fibers in the nonwoven fabric, the tensile strength is given in kg per kg. cm width and the toughness is given in kg / cm ..

Table.

Binder, Binder Handle and Tensile Strength Toughness composition, in non-woven kg / cm width kg / cm _jo fabric _ _ _ 19.9 79.3 0.8 35 6-1.6 2 22.15 77.2 0, 65 "6 1.8 3 21.7 76.9 1.4" 52 5