DE1135413B - Process for the production of a fleece from non-feltable, randomly distributed fibers - Google Patents

Description

GERMAN

PATENT OFFICE

R21674IVc / 8k

REGISTRATION DATE: AUGUST 12, 1957

NOTICE
THE REGISTRATION
AND ISSUE OF
EDITORIAL: AUGUST 30, 1962

The invention relates to a method of manufacture nonwoven fiber webs. Such bonded nonwoven fibrous products are for the Production of flat or three-dimensional objects suitable, including insulating material 5 and the like belongs to what will be described in detail.

The expression »random. Arrangement «is supposed to be the arrangement of fibers in a denote carded fleece, in which often both a partial orientation and other arrangements are present in which the fibers are arranged completely randomly to one another.

So far, binders made from natural rubber milk and aqueous binders have been used to adhere such nonwovens Dispersions of synthetic rubbers, such as. B. styrene copolymerized with butadiene, acrylonitrile etc., known; however, these binders have several disadvantages. This includes the Tendency to yellow the bound products so that it is difficult to use even by use optical brighteners or white pigments such as titanium dioxide to counteract this undesirable effect. These rubber-like binders also cause the rubber-like feel of the Fleece and suppress the fiber-like properties in the fiber structure. On the other hand, if the also known binders made from polyvinyl acetates or chlorides or their copolymers are used, the 'fleece gets a paper-like, wrinkled and brittle feel, as it would be thin and brittle. Nonwovens obtained in this way also make a noise when crumpled up, what kind of Papers is indicative. By using thermoplastic polymers, e.g. B. from simple Esters of acrylic or methacrylic acid, nonwovens are obtained in which the binder remains thermoplastic permanently and tends to change if the webs become excessive Exposed to temperatures. The polymers have simple acrylic and methacrylic acid esters also the property on hydrophobic types of fibers, such as nylon, vinyl resin fibers, cellulose esters or Polyesters, bad to adhere to. Furthermore, many of the previously used binders, including aqueous Dispersions of rubber, synthetic rubbers and acrylic acid esters include, the pronounced tendency during the drying of the nonwovens on the surfaces of the fibrous products on which the Dispersions have been applied to migrate. So from the British patent 745 065 is the Production of nonwovens known, their fibers process for production

a fleece made of non-feltable,

randomly distributed fibers

Applicant:

Rohm & Haas Company, Philadelphia, Pa. (V. St. A.)

Representative: Dr.-Ing. H. Ruschke, patent attorney, Berlin-Grunewald, Auguste-Viktoria-Str. 65

Claimed priority: V. St. v. America of August 13, 1956 (No. 603 832)

Benjamin Berryl Kine and Nathaniel Abraham Matlin, Levittown, Pa.

(V. St. A.),
have been named as inventors

are directional in a certain way and are characterized by a special type of distribution of the Binders, which can generally be natural or synthetic resins, distinguish, as a result of which special stretching and stretching properties can be achieved. Also in British patent specification 723 901 is a process for the production of interwoven nonwovens using suspended polymers, including polyethylene acrylate, described, with the precipitation of the polymers on the Fibers a cationic, water-soluble, basic, nitrogen-containing, organic polymer is used. From the prior art shown, a polymeric binder for nonwovens has acid groups contains, not known. Due to the presence of such acid groups in the binder polymer are the fleece products produced in contrast to the previously known fiber fleeces particularly resistant to dry cleaning processes. If you z. B. simple polymers of ethyl acrylate as suggested in the UK patents cited above becomes, one arrives at a fleece in which the polymer is undesirably thermoplastic and is soluble. In contrast, the process product of the present invention contains after heating it has become practically insoluble

209 634/365

are, is preferably used together with the copolymer, an aminoplast to the To increase the resistance of the fleece to solvents and heat. A certain ver-5 These properties are often improved when an aminoplast is used in conjunction with copolymers, which contain carboxylic acid units, in the upper part of the given broad range is used, but in these cases this is

Binder with increased strength compared to dry cleaning, washing processes and the like.

It has also been proposed to bond bonded webs by treating a fibrous web or a mat with an aqueous dispersion of a compound of a polyvalent metal, the polyvalent Provides metal ions, and a water-insoluble linear copolymer of monoethylenically unsaturated monomeric units leading to

0.5 to 7 mol percent of units with carboxyl ίο aminoplast usually not required,
groups exist to produce, this by The copolymer can be in the form of the free

a nonionic emulsifier is maintained in a stable acid (-COOH groups) or in the form of a dispersed state. When drying alkali metal salt, e.g. B. of sodium, potassium or the treated fibrous product, the mixed lithium (z. B. - COONa groups), an ammopolymer is crosslinked by the polyvalent metal to a 15 nium salt (COONH ₄ ) or a salt of an insoluble and infusible state . water-soluble amine, such as methylamine, diethyl

The present invention, on the other hand, enables amine, triethylamine, mono-, di- or triethanol via the production of nonwovens by means of an amine, morpholine, etc., can be used. Im all-binder, using an aqueous common, it is appropriate to use the copolymer system without the inclusion of a compound of a dispersion at a pH of at least about 5 polyvalent metal and without the aforementioned and preferably a pn value between 6 and 10 Disadvantages is applied that have to be applied for so far.

known binder systems are indicative. In the connection of the fibers is made with a

In the finished fleece, the binder is obtained in a clear, practically colorless binder, which is infusible and insoluble. The 25 on all types of fibers and surfaces and even the main advantage of the present invention compared to silicic acid-containing, to which glass fibers belong, the use of dispersions of a compound is well adhered, which was previously due to the difficulty of using a polyvalent metal and a water-insoluble colorless binder found that are adequately adherent to silicic acidic linear copolymers of 0.5 to 7 mol-containing material, only percent of units containing carboxyl groups was difficult to process. The binders of the present invention are that both anionic emulsifiers are also essentially free and that nonionic emulsifiers are used in the preparation of the aqueous copolymer dispersions
can be used without in view
difficulties arise on their persistence. 35
The versatility of the present invention

The binder used is such that it complies with the various processes involved in its manufacture of fibrous products can be easily adapted.

The method according to the invention for producing a fleece from non-feltable, randomly distributed Fibers using a resin binder is to use as a binder

of discoloration when exposed to elevated temperatures, e.g. B. during drying, melting or hardening used, exposed.

The copolymer used in the binder of the present invention contains one Variety of carboxyl groups either in the free acid form or in the salt form, through which it is is enabled when heated in the presence or in the absence of an aminoplast and in the presence suitable catalysts, which generally have acidic properties, are insoluble and infusible will. The particularly thermally hardened fleece has improved resistance to

water-insoluble polymer from mono-ethylenic washing, dry cleaning and stains, against unsaturated monomers with a content of 0.5 different chemicals and against heat containing up to 10 percent by weight of carboxyl groups compared to such binder systems as the monomers used, this water-insoluble rubber milk or aqueous dispersions of borrowed polymer either in the free acid form of synthetic rubbers or polymers of or in the form of the ammonium, alkali or amine 50 acrylic or vinyl esters that have hitherto been used, salts can be present, and that the binding die according to Nonwovens containing agents obtained according to the present invention can be heated to higher temperatures than the nonwovens obtained after half of the 7> value of the polymer and known processes, then the dried nonwoven is grounded to 110 to 400.degree. C. without this suffer a discoloration without overheating. The heating time is at higher temperature-55 that the stiffness is increased or an adverse temperatures only ¹ I ₄ minute and occurs at a lower temperature-decomposition. You are through an excellent 1/2 hour or more. In general, hardening at the temperatures mentioned increases the resistance to ironing and does not become tacky, as is the case with the solvent resistance and heat resistance of the thermoplastic used as a binder in the case of copolymers for many purposes in an appropriate manner. The carboxyl groups make it possible apparently, especially if the copolymer also lent a more versatile adhesion of the binder contains at least 2.5 percent by weight of dicarboxylic acid on hydrophilic fibers such as cotton, cellulose units, z. B. those that are obtained from itaconic acid rayon and the like, but also on hydrophobic ones. Or at least 5 percent by weight of fiber types, such as nylon, polyamide fibers, fibers from monocarboxylic acid units, such as those made from 6 ₅ vinyl resins, copolymers of vinyl chloride Acrylic or methacrylic acid can be obtained. If with vinyl acetate or with acrylonitrile, polymers less than the smallest possible, just stated would consist of 70 to 90% acrylonitrile with different proportions of carboxylic acid units in addition to monomers such as vinyl chloride, vinyl acetate, all of them

Vinyl pyridines, such as 2-vinyl pyridine or mixtures of such additional mixed monomers, fibers Polyesters, such as poly (ethylene glycol terephthalate), and fibers made from cellulose esters, such as cellulose acetate, Cellulose acetate propionate, cellulose acetate butyrate, etc. Because of the characteristic adhesive strength of the binders used in the present invention on both hydrophilic and hydrophobic fiber types the fleeces are also resistant to "stripping" and abrasion. The one used in the present invention Binder can be dried and hardened to an insoluble and infusible state so that the bonds are not destroyed even when the heat is applied vigorously. Fleece with a content of binder according to the present invention can in the wet state or during the beginning of drying, but before it is completely dry, be permanently embossed. When drying z. B. on a suction screen, the screen pattern is permanently impressed on one side of the product and is not destructible even by calendering. The binder can be applied to parts of the fibrous Product, e.g. B. on one or both sides of the same, applied; a practically uniform one Distribution is always preserved because the binder does not tend to break after application to migrate within the fleece to its surfaces during drying. In addition to the specified Binding agents can also be a linear copolymer, aminoplast condensates that cure in the heat and a curing catalyst for the aminoplast or used together to cure the carboxyl group-containing polymer will.

To carry out the method according to the invention, a fleece, the fibers of which are completely consist of non-proteinaceous fibers that cannot tangle with the aqueous dispersion of the water-insoluble linear polymer containing the carboxyl groups, impregnated. The molecular weight the polymer should be about 100,000 to 10,000,000.

The aqueous dispersion is preferably carried out by emulsion polymerization in the presence of an emulsifying agent of at least one monomer containing carboxyl groups, such as acrylic acid, methacrylic acid and itaconic acid.

The emulsifiers or dispersants used in the preparation of the emulsions of the monomers before the Copolymerization or the dispersion of the polymer can be used after the polymerization can be of the anionic or nonionic type, or it can be a mixture of the two types be used.

The fleece to be adhered can be made by carding if the fibers are long and pliable are so that they are accessible for carding. Natural fibers such as jute, sisal, ramie, and hemp Cotton as well as synthetic fibers or threads can be used. These are called synthetic fibers from z. B. cellulose esters, vinyl resins, polyvinyl chloride, copolymers of vinyl chloride with Vinyl acetate, vinylidene chloride or acrylonitrile, which contain a larger proportion of vinyl chloride in the Contain polymer molecule, polyacrylic acid nitrile and copolymers of acrylic acid nitrile with vinyl chloride, Vinyl acetate, methacrylic acid nitrile, vinyl pyridine or with mixtures of such comonomers, which contain a larger proportion of 75 to 95% acrylonitrile in the copolymer molecule, understood, also fibers from condensates, such as polyamides, polyester and the like Carding obtained nonwoven can be treated according to the present invention, in general However, it is necessary and expedient to superimpose a large number of such nonwovens in order to the To give the mat sufficient strength for the intended use, e.g. B. at the Manufacture of thermal insulation. In the manufacture of such a mat you can take turns Layers of the carded nonwovens are placed one on top of the other with their fiber orientation directions that these occupy an angle of 60 or 90 ° with respect to the intermediate layers.

Usable mixed monomers which tend to

To give soft and pliable polymers when they are copolymerized with one of the above-mentioned monomers containing carboxyl groups are those which give solid polymers with a Γί value below 15 to 20 ° C. The mentioned Ti value is the transition temperature or bending temperature, which is found by plotting the rigid modulus against the temperature. A convenient method for determining rigid modulus and transition temperature is described by I. Williamson, British Plastics, 23, pp. 87-90 (September 1950). The 7i value used here has been determined at 300 kg / cm ² .

The copolymerizable neutral mers which form soft and solid polymers in the presence of catalysts which form free radicals include primary and secondary alkyl acrylates, even with alkyl substituents of up to 18 or more carbon atoms, primary or secondary methacrylates with alkyl substituents of 5 to 18 or more carbon atoms or other monovinylidene compounds, as indicated above, which can be polymerized with catalysts which form free radicals to form soft solid polymers below 80 ° C., including vinyl esters of saturated monocarboxylic acids with more than 2 carbon atoms. The preferred monovinylidene compounds are the stated acrylates and methacrylates, and of these, the most useful esters are those whose alkyl groups contain no more than 12 carbon atoms.
As polymerizable monovinyl monomers, which themselves give hard polymers, alkyl methacrylates whose alkyl groups contain not more than 4 carbon atoms, also tert-amyl methacrylate, tert. -Butyl or tert-amyl acrylate, cyclohexyl or benzyl acrylate or methacrylate, acrylonitrile or methacrylonitrile can be used. Styrene, vinyl chloride, chlorostyrene, vinyl acetate, p-methylstyrene, acrylic acid amide and methacrylic acid amide also form hard polymers. It is advantageous to copolymerize the monomer containing carboxyl groups with a mixture of two or more different monomers, one or more being selected from the series forming hard polymers and another series being selected from the series forming soft polymers. An example of this is a copolymer of 8 to 55% ethyl acrylate, 44 to 90% methyl methacrylate and about 3 to 6% methacrylic acid.

The aqueous dispersions used as binders can contain only 1% and up to 60% of the resinous Copolymer, based on weight units, contain. It is preferred to use dispersions to use, which contain 30 to 50% of resin solids. Usually the dispersion is on a resin content of 1 to 35% and preferably 2 to 30% diluted, in which form they are by spraying, Immersion or by transfer rollers is applied to the fleece.

The binder of the present invention can also be applied in admixture with other binders will. Mixable binders are z. B. glue or resin-forming condensates, especially

400 percent by weight binder based on the weight of the fibers, depending on the intended use Intended use of the fleece, included. If the binder is mainly intended to serve the

5 fibers to bind to form a coherent uniform structure in which the largest possible Permeability in connection with the least possible change in the fibrous Handle is obtained, will be 2 to 50 percent by weight

ία of solid binder components, referring to the Fibers, used, with a smaller proportion of course, the greatest possible permeability and results in minimal change in the fibrous feel. According to the invention

Aminoplasts, such as urea-formaldehyde, melamine 15 obtained products are z. B. for sanitary purposes Formaldehyde and the like can also be used, such as for table napkins, drool bibs, potentially adhesive fibers within the fleece tablecloths, hygienic mouth towels, diapers, in connection with a binding agent of the present wound dressings and compresses. It is for that the invention possible. in the proportions just given.

The zumischbare Aminoplastbindemittel can characteristic in ²⁰ supported binder that combiner amount up to 25 weight percent of the weight proportionate little or no "encryption Fensterdes carboxyl group-containing polymer formation" occurs, that is, the spaces between turns, will be where 2 preferably up to 11% . the fibers remain open, whereby a very porous, the use of an aminoplast together with a loose fleece is obtained. Of course, the carboxyl group-containing polymers ² 5 density of the product by applying pressure in the present invention is used to modify the handle to different degrees before, or in many cases, and may increase the effects and changes after curing the product. Strength and resistance to being ficated.

Creasing, wrinkling and pinching. Fibrous, nonwoven products that are 40 to

If an aminoplast binder is stolen together with 30 150 percent by weight of the binder of the present polymer containing carboxyl groups according to the invention, based on the fiber weight, the system can either be kept in the, for. B. useful for clothing purposes, aqueous dispersion of the polymer or by for inner clothing in coats, suits, etc. separate application to a mat or a fleece or for outerwear, such as for blouses, skirts, before or after the application of the aqueous dispersion 35 shirts, etc. The sion of the polymer a catalyst introduced from such nonwovens need not be ironed or pressed in order to harden the copolymer in order to accelerate their appearance, their shape and the aminoplast binder. The cata- their handle after washing by hand, machine lyser can be used in an amount up to 2% by weight cleaning or dry cleaning, percent, preferably from ¹ I ₂ to 1 percent by weight, 4 ° In addition to the usual uses of the aminoplast indicated above. The household and clothing catalyst used can be chosen so that a purpose the fibrous products find this excessive deterioration of the fibers used in the particular invention where 2 to 100 percent by weight of the fibrous product binder is used per weight of the fibers avoided . In any case, however, it is an acidic or potentially acidic substance, the latter being used as wipes, lining materials for the lost catalyst and acid packing when heated, as a filter or the like.

releases. If z. B. Cellulosic fibers used in fibrous products of the present invention

an ammonium salt, such as ammodes, can be 100 to 400 percent by weight of the binder Nium chloride or diammonium phosphate, or a 50 per fiber weight used, are be-amine hydrochloride salts Can be used as the special for durable and resistant tech hydrochloride of triethanolamine, monoethanol- niche seals, packings, etc. can be used. the amine, diethylamine, etc. Products that contain 20 to 200 percent by weight of the binding agent

The proportion of the binder by weight by means of the present invention, based on the fiber of the fiber component, based on the property, can vary widely depending on the property of the desired product. In the case of structures either as intermediate layers or under-production of preforms, which are to be converted into shaped counter-layers in connection with plastic films and stands, panels, such as made of polyethylene, nylon, etc., or in 2 to 10% of the binder are preferred the present inventions conjunction with woven, braided, knitted, droppings, based on the weight of the fibers, verwen- ⁶ ° knotted or tangled fabrics useful det. In the production of insulating compounds, it is essential that the treated

Amount of binder used in the lower fibrous product, i.e. H. of the fibrous product that Part of the range just given, when the binder dispersion is supported, is at one temperature the binder predominantly of the surface or those above the Tj value of the binder mixed poly surfaces of the product applied adjacent 65 merisats is carried out in order to obtain a suitable ver

or when it is applied together with other binders.

The fleece obtained according to the invention can be 2 to

to achieve agreement and connection of the fibers.
As stated above, in order to achieve setting,
no special heating required if the

Ti value of the copolymer is about 30 ° C. or less, but it can be advantageous to accelerate the drying of the binder to the cured state. In order to make the binder infusible, hardening is carried out at elevated temperatures. The curing temperatures for curing the binder can be up to 400 ° C, but they are preferably in the range of about 110 to 350 ° C.

example 1

IO

(a) A carded fleece of 25 g / m ² made of viscose fibers and bleached cotton in a ratio of 75:25 is treated with an aqueous dispersion made up of 100 parts:

25.0 parts of the ammonium salt of a Emulsionsmischpolymerisates from 66 ° / ₀ ethyl acrylate, 32.7% methyl methacrylate and 1.3% methacrylic acid,

2 parts of tert-octylphenoxypolyethoxyethanol with about 35 oxyethylene units (emulsifier and dispersant),

0.4 parts octylphenoxyethoxysodium sulfate (wetting agent),

0.1 part silicone (defoamer)

25th

contains, at an uptake ratio of about 600% of the fiber weight (based on wet basis) impregnated. The fleece is dried at 107.2 ° C. for 1.5 minutes and cured at 177 ° C. for 1.5 minutes. In the resulting nonwoven has a fiber to binder ratio of about 33:67. It is very permeable and has a soft and elastic handle.

(b) The process according to (a) is repeated with a carded fleece made of Pyrex glass fibers (17 g / m ² ), the impregnation with the aqueous dispersion being carried out at an absorption ratio of 300% (wet basis). The fiber and binder are present in a ratio of 53:47 in the finished fabric, which is extremely permeable and soft, but still holds tightly together.

Example 2

The procedure of Example 1 (a) is repeated with a similar aqueous dispersion comprising 25.0 parts of the sodium salt contains a Emulsionsmischpolymerisats of 85% ethyl acrylate with _150/0 of methyl methacrylate, wherein the acrylate groups have been hydrolyzed to about 2% acrylic acid in the Introduce mixed polymer. A permeable, soft and cohesive fleece is obtained.

Example 3

The procedure of Example 1 (a) is repeated with a similar aqueous dispersion to that 25.0 parts of the sodium salt of an emulsion copolymer of 87% ethyl acrylate, 10.5% methyl methacrylate and contains 2.5% itaconic acid. A well-bound fleece is obtained, the opposite Resistant to solvents and heat.

Example 4

Contains itaconic acid. A fleece similar to that of Example 3, but with a softer feel, is obtained obtain.

Example 5

^{A nonwoven fabric (50 g / m 2} ) made of colorless nylon and a colored, glossy acetate fiber in a ratio of 50:50, obtained by separation in a stream of air, is treated with an aqueous dispersion of 100 parts:

27.0 parts of the sodium salt of a copolymer of 10% ethyl acrylate, 89.5% methyl methacrylate and 0.5% methacrylic acid,

2 parts of tert-octylphenoxypolyethoxyethanol with about 35 oxyethylene units (emulsifier and dispersant),

3.0 parts of dimethylol-N, N'-ethylene urea, 0.5 parts of ammonium chloride,

0.5 part of octylphenoxyethoxysodium sulfate (wetting agent),

0.1 part silicone (defoamer)

contains, impregnated to an absorption ratio (wet basis) of 300%. The fleece is 1.5 minutes dried at 107 ° C and cured at 177 ° C for 6 minutes. In the obtained fleece there are fibers and Binder in a ratio of 55:45. It's pretty see-through and has a texture-like feel to it. After washing and drying, no ironing or pressing is required to keep the shape or appearance or to restore the feel of garments made from this fabric.

Example 6

A nonwoven fleece (64.8 g / m ² ) made of a colorless viscose fiber and fibers made of colored polymer with a content of 85 to 90% acrylonitrile in a ratio of 50:50 and an aqueous dispersion, each 100 Parts:

27 parts of the triethylamine salt of a copolymer of 7% acrylic acid and 93% n-butyl acrylate,

2 parts of tert-octylphenoxypolyethoxyethanol with about 35 oxyethylene units (emulsifier and dispersant),

3.0 parts of a urea / formaldehyde / methanol condensate,

0.5 parts diammonium phosphate,

0.5 part of octylphenoxyethoxysodium sulfate (wetting agent),

0.02 part silicone (defoamer)

contains, impregnated to an absorption ratio of about 300% (wet basis). The fleece is at Dried at 107 ° C for 1.5 minutes and cured at 177 ° C for 5 minutes. In the product the ratio is from fiber to binder 55:45. It has good cohesion, is permeable, soft and has the feel of a fabric.

The procedure of Example 1 (a) is repeated with a similar aqueous dispersion to that 25.0 parts of the nairium salt of a mixed emulsion pol ymerisats from 97.5% ethyl acrylate and 2.5%

Claims (11)

PATENT CLAIMS: 1. A method for producing a fleece from non-feltable, randomly distributed fibers using a resin binder, characterized in that a water- 209 638/365 insoluble polymer from monoethylene unsaturated monomers with a content of 0.5 to 10 percent by weight of carboxyl groups (—COOH) -containing monomers are used, this water-insoluble polymer either in the free acid form or in the form of Ammonium, alkali or amine salts can be present, and that one containing the binder Fleece dries at a temperature above the Ti value of the polymer and then the dried fleece is heated to 110 to 400 ° C. 2. The method according to claim 1, characterized in that containing as carboxyl groups Monomeric acrylic acid, methacrylic acid or itaconic acid can be used. 3. The method according to claim 1 or 2, characterized in that the polymer also at least contains an ester of one of these acids. 4. The method according to claim 1 to 3, characterized in that the copolymer additionally contains an aminoplast. 5. The method according to any one of the preceding claims, characterized in that the The nonwoven used contains at least 50% nylon fibers. 6. The method according to any one of claims 1 to 5, characterized in that the fibers become one predominantly consist of fibers with smooth surfaces. 7. The method according to any one of claims 1 to 5, characterized in that the used Fleece made from cellulose fibers, nylon fibers, vinyl resin fibers, fibers made from acrylonitrile polymers, Poly (ethylene glycol terephthalate) fibers or mixtures thereof. 8. The method according to any one of claims 1 to 5, characterized in that the used Fleece at least a predominant proportion of a mixture of nylon and cellulose fibers contains. 9. The method according to any one of claims 1 to 5, characterized in that the used Fleece at least a predominant proportion of a mixture of cotton and contains regenerated cellulose fibers. 10. The method according to any one of claims 1 to 5, characterized in that the used Fleece at least a predominant proportion of a mixture of nylon and cellulose acetate fibers contains. 11. Method according to one of the preceding Claims, characterized in that the binder on the fibers in the form of an aqueous Dispersion is applied from the fibers during the formation of the fleece. Considered publications:
British Patent Nos. 723 901, 745 065. © 209 638/365 8.62