EP0261175A1

EP0261175A1 - Fiberous batt and method for producing such

Info

Publication number: EP0261175A1
Application number: EP87901970A
Authority: EP
Inventors: George S. Buck, Jr
Original assignee: Fiberlok Inc
Current assignee: Fiberlok Inc
Priority date: 1986-03-11
Filing date: 1987-03-06
Publication date: 1988-03-30
Also published as: HUT46752A; EP0261175A4; CN87102669A; WO1987005639A1

Abstract

Un procédé de liaison de fibres consiste à mettre en contact les fibres avec un alliage plastique particulaire. L'alliage plastique comprend une résine thermoplastique et un composé organique cristallin présentant un point de fusion compris entre 20 et 200°C ainsi qu'un point d'ébullition compris entre 100 et 450°C, constituant un solvant de la résine. Le mélange d'alliage plastique et de fibres est chauffé pour fondre l'alliage et lier les fibres.A fiber bonding process involves contacting the fibers with a particulate plastic alloy. The plastic alloy comprises a thermoplastic resin and a crystalline organic compound having a melting point between 20 and 200 ° C as well as a boiling point between 100 and 450 ° C, constituting a solvent for the resin. The mixture of plastic alloy and fibers is heated to melt the alloy and bind the fibers.

Description

FIBEROUS BATT AND METHOD FOR PRODUCING SUCH

Some years ago, a process was developed for producing a fiberous batt by contacting fibers with a fiber binder based on certain polymers. This process and product are described in United States Patents 3,993,518, 4,047,991, 4,050,977, 4,051,294, 4,053,673, 4,053,674, 4,457,793 and 4,550,050.

The prior polymers are employed in dry, particulate form, thus avoiding the packing and matting of the fiber pad or batt that is caused by using polymers in solution, suspension or emulsion form, and at the same time eliminating the cost of removing a solvent or aqueous carrier with heat.

One problem encountered in the prior art described in U.S. P. 3,993,518, 4,047,991, 4,050,997, 4,051,294 and 4,053,674 is that resins which contain high percentages of polyvinylidene chloride tend to decompose, especially when heated to approximately 400°F to cause them to melt, releasing hydrochloric acid. This acid causes the corrosion of the processing equipment and even of the metal parts of buildings, as well as causing environmental problems if not captured from exhaust stacks. For this and other reasons, an improved resin was developed (USP 4,456,793) and 4,550,050) which was more stable at the temperatures which decomposed the prior resin and had other unexpected advantages.

With either resin described in the above patents, however, it is necessary to operate the curing ovens used in the preparation of the bonded fiber batt at temperatures ranging from 375°F to 450°F, depending on the size of the oven and the production requirements. Such temperatures have a number of important disadvantages, namely:

A. The use of high curing temperatures, as noted above, can cause resin decomposition, more with some resin than others, and the release of corrosive hydrochloric acid.

B. Maintenance of high temperatures in ovens requires an undesirably large amount of thermal energy and excessive supplies of valuable fuel. C. High oven temperatures cause many thermoplastic fibers to soften and shrink and cause unnecessary and undesirable compaction of batts and pads intended to be lofty in construction.

D. High temperatures employed for the curing of certain waste or recycled fibers may produce a caramel-like char odor in batts and pads which makes them unsaleable.

E. If resins require high temperatures for their cure in fiber bonding processes the size and cost of ovens necessary to raise the product to its curing temperature can become excessive.

F. The re-heating of batts for use in molding presses to make such products as automative sound-absorbing pads and liners is more difficult and more costly if unduly high temperatures are required in the re-heating ovens.

For these and other reasons which will become apparent:, it is an object of this invention to provide an improved process for bonding fibers to form cohesive batts and pads at lower temperatures than would be effective in the prior art.

Furthermore, it is an object of the present invention to provide an improved process for the bonding of fibers, which improved process is substantially free of one or more of the disadvantages of prior processes.

Another object of the present invention is to provide an improved batt having properties not possessed by prior batts.

Still another object of the present invention is to provide bonding agents which replace prior polymers, which bonding agents have lower melting points than the melting points of prior polymers.

An additional object of the present invention is to provide an improved process which is capable of being employed with polymers that have heretofore been found to be unsuitable as binding agents.

Still another object of the present invention is to provide an improved process that results in bonding agents with a firm, hard form after curing and with minimum plastic deformation in use. Still another object of the present invention is to provide an improved process for producing batts bonded with substances that can easily be produced within the desired range of particle sizes because of their favorable performance in air-milling or grinding.

Yet another object of the present invention is to provide an improved batt having better loft than prior batts.

An additional object is to provide an improved process that can employ fibers having lower melting points than heretofore possible.

An additional advantage of the present invention is to provide a process that employs less energy than prior art processes.

Other objects and advantages of the present invention will be apparent to those skilled in the art by reference to the following detailed description and drawings wherein:

Figure 1 is an elevation view of an apparatus suitable for practicing the process of the present invention.

Figure 2 is a plan view of the apparatus of Figure 1.

Figure 3 is a sectional view taken along line 3-3 of Figure 2.

Figure 4 is an elevation view of another apparatus for producing bonded-fiber pads and batts which is also suitable for practicing the process of this invention. A number of variations of this process generally termed the "air-lay" method, can be usefully employed in this invention.

The above and other objects are accomplished according to the present invention by providing a process for bonding fibers comprising the steps of contacting the fibers with a particulate plastic alloy comprising a compound and a thermoplastic resin to form a mixture of the plastic alloy and the fibers. This mixture is then heated to melt the plastic alloy and to bind the fibers.

In order for the compound to be successful in the formation of the plastic alloy useful in the present invention, the compound must have certain properties. The compound must be a crystalline organic compound at standard temperature and pressure. By standard temperature and pressure, it is meant room temperature of 20°C and atmospheric pressure of 760 mm of mercury. Furthermore, the compound must have a melting point of 20 to 200° and preferably from 40° to 150°C at atmospheric pressure. Another requirement for the compound is that it have a boiling point of 100° to 450°C and preferably 200° to 450°C at atmospheric pressure. Another essential requirement for the compound in order for it to be useful in the present invention is that it be a solvent for the resin to be used.

In addition to the required properties described above for the compound, it is highly desirable, although not absolutely necessary, that the compound have certain additional properties. For example, the compound should have a vapor pressure less than 40 mm of mercury at 200°C. This property is necessary in order to avoid excessive sublimation. The compound should be relatively non-toxic and non-irritating to factory workers. It should have no objectionable odor. It should not decompose significantly when heated to 400°F for 2-4 minutes. It should contain at least one benzene ring in its structure, and preferably should be insoluble or only slightly soluble in water.

The term compound, as used herein, means a single chemical compound or mixture of two or more chemical compounds. In many cases mixtures of two or more compounds yield a eutectic solution which gives a lower melting point resin alloy than can be obtained from any one of the compounds by itself. The term resin, as used herein, also includes mixtures of more than one resin, as well as single resins.

It is possible, and certainly appropriate, to describe the compounds useful in this invention entirely in terms of their physical properties, since there is no chemical reaction involved in the normal practice of this invention and it is the physical properties of the compound which govern both the preparation of the plastic alloy and its functioning in the process described herein. Examples of suitable compounds, or compound classes, include: acenaphthylene and 5-chloro acenaphthene; aniline derivatives, including 2-amino N-phenyl aniline, 4-amino N-phenyl aniline, 3-hydroxy N-phenyl aniline, 4-hydroxy N-phenyl aniline; organic aromatic amines, such as 2-naphthyl phenyl amine, 1-naphthyl 4-tolyl amine, tri-benzyl amine, tri-phenyl amine, di-benzyl amine; substituted anilines, such as N-benzylidene aniline, 2-bromo 4,6, dichloro aniline,

2.4 dichloro aniline, 2,5 dichloro aniline, 3,4 dichloro aniline, 3,5 dichloro aniline, 3-nitro aniline, 2 nitro aniline, 4 nitro aniline, N, N dimethyl aniline, 2,4,6 tri-bromo aniline, 2,4,6 tri-chloro aniline, 2,4,5 tri-chloro aniline; anthracene derivatives like 9,10 di-hydro anthracene and 9-nitro anthracene; aminoazobenzene; 4-ethoxy aminoazobenzene; 4 methoxy aminoazobenzene; organic aromatic aldehydes like 3,4 dimethoxy benzaldehyde and 3-hydroxybenzaldehyde; benzene derivatives and substituted benzenes including 1,4 bis chloromethyl benzene, 1-bromo

4 chloro benzene, 1 bromo 2,3 dichloro benzene, 2 bromo 1,3 dichloro benzene, 1-bromo, 2,3 dinitro benzene, 1 bromo 4 nitro benzene, 2 chloro 1,3 dinitro benzene, 1 chloro 4 nitro benzene, 1,2 dimethoxy 4 nitro benzene, 1,4 dinitro 2 methoxy benzene, 1 methoxy 2,3,4,6 tetrabromo benzene, 2 methoxy 1,3,5 trichloro benzene, 2 methoxy 1,3,5 trichloro benzene, 1 nitro 2,4,5 trichloro benzene, 1 nitro 2,4,5 trimethyl benzene, pentachloro benzene, 1,2,3,5 tetrabromo benzene, 1,3,5 trinitro benzene; benzil; benzoic acid and various derivatives including benzoic acid amide, benzoic acid anyhydride, benzoic acid methylene diester, benzoic acid phenyl ester, 4 chloromethyl nitrile benzoic acid,

2.5 dimethyl benzoic acid, 2,6 dimethyl benzoic acid, 2 ethyl benzoic acid, 2 methoxy benzoic acid, 2 methyl benzoic acid,

3 methyl benzoic acid and 2 phenoxy benzoic acid; 4 bromobenzophenone; 3,3' dimethyl benzophenone; 3 nitro benzophenone; benzophenone; benzoin; 5,6 benzoquinoline; biphenyl and derivaatives, including 2 acetamido biphenyl and other acetamido derivaties, 4 acetyl biphenyl, benzyl-, bromo-, chloro-, dimethyl-, amino-, diamino-, and nitro-biphenyls; 2 biphenyl carboxylic acid; diphenyl disulfide; 1,1,1',1' benzhydril ether; 1,1' dinaphthyl ether; 1,2' dinaphthyl ether; 2,2' dinaphthyl ether; 2,2' dimethoxy diphenyl ether; 2 methoxy diphenyl ether; diphenyl ethyne; fluoranthene; fluorene; 9 fluorenone; glycerol 1, 3 diphenyl ether; 3 methyl isoquinoline; 6 methyl isoquinoline; benzyl phenyl ketone; 1,2' dinaphthyl ketone; di-2 thienyl ketone; 1 naphthyl 2 tolyl ketone; diphenyl ester of maleic acid; 4 amino phenyl diphenyl methane; bis 4 amino phenyl methane; chloro (tri phenyl) methane; di (1-naphthyl) methane; diphenyl (3 tolyl) methane; (2 naphthyl) phenyl methane; triphenyl methane; (1 naphthyl) phenyl methane; naphthalene; naphthalene derivatives including 2 acetyl hydroxy naphthalene,

1 benzyl 2 hydroxy naphthalene, 2 benzyl hydroxy naphthalene,

2 bromo naphthalene, 2 chloro naphthalene, 1 chloro 5 nitro naphthalene, 1,3 dichloro naphthalene, 2,3 dimethyl naphthalene,

2 hydroxy naphthalene, 1 nitro naphthalene, 2 phenyl naphthalene and 2,3,6 trimethyl naphthalene; 3,4 dihydro naphthoic acid; phenanthrene; 9 bromo phenanthrene; 7 isopropyl 1 methyl phenanthrene; phenanthridine; phenol derivatives, including

3 bromo 5 chloro phenol, 2,6 dichloro phenol 2,4,6 tribromo phenol, 2,4,6 trichloro phenol and 3,4,5 trichlorophenol; triphenyl phosphine; phosphonitrilic ester trimers and tetramers, including their phenoxy derivatives; phthalic acid and derivatives such as 4 chloro phthalic acid, 3,4 dichlorophthalic acid and phthalic acid anyhydride; 2,6 dimethyl pyridine dicarboxylic acid; quaterphenyl 0,0'; 2 amino, 4 methyl quinoline; 7 amino,

8 methyl quinoline; 2 phenyl quinoline; 6 phenyl quinoline;

1,1' dinaphthyl sulfide; m. terphenyl; thianthrene; thioxanthrene; substituted toluenes, including a amino 2 bromo toluene, 3 amino

4 methoxy toluene, 2 amino 6 nitro toluene, 3 bromo 5 nitrotoluene, 2 chloro 6 hydroxy toluene, 1,4 dichloro 5 hydroxy toluene, 2,4 dinitro toluene, a,a, 2,3,4,5,6 heptachloro toluene, a,a,2,3,4 penthachloro toluene, and 2,3,4,6 tetrachloro toluene; aromatic urea derivatives, for example, 1,3 diethyl 1,3 diphenyl urea, 1,3 (bis 2 ethoxy phenyl) urea and 1 phenyl urea; xanthene and xanthone. The compounds listed above do not include all those which can be used in this invention. They are also not equally satisfactory when used by themselves. Their usefulness is increased, in many cases, by admixture with other compounds listed above. The mixing of two or more compounds often decreases odor from one component. In many cases, two or more compounds give a eutectic melting point which is lower than that of the individual compounds.

The selection of a compound for the preparation of a particular plastic alloy for a commercial fiber bonding operation depends on the properties of the compound and the resin, and on the characteristics desired in the fiber-bonding product. For example, in most cases strong odor, toxicity, easy sublimation, or a tendency to explode will be enough to eliminate a candidate compound, although there are special applications in which even some of these properties may be useful. Also, a melting point in the 100°-130°C range, chemical stability, a high boiling point (350°-450°C), and ease of preparation from inexpensive, readily available raw materials favor the selection of a particular compound. The extent to which the compound, which may be referred to as an antiplasticizer, dissolves the resin is always important.

One group of compounds which are particularly useful in the present invention have the formula I :

wherein m is an integer of 0 or 1, n is an integer of 0 to 5, inclusive, p is an integer of 0 to 5, inclusive,

R is a member selected from the group consisting of S, SO, SO₂, O, CH₂, CHOHOCHOH, CHOHO , CO, NH, COCO, NR', .CHR' , CHR'O and CR'R" wherein R' and R" each independently represent a lower alkyl group having 1 to 8 carbon atoms or a phenyl group, and X and Y are each independently selected from the group consisting of Cl, Br, NH₂, NO₂, COOH, OH, carbonyl having 1 to 8 carbon atoms, alkoxy having 1 to 8 carbon atoms, alkyl having 1 to 8 carbon atoms, phenyl, phenoxy and naphthyl, said X's being the same or different when n is greater than 1 and said Y's being the same or different when p is greater than 1 .

Examples of compounds having the structure of formula I are listed below. Some of the most useful compounds, or anti-plasticizers, are found to have this generalized type of structure, although some of the compounds listed below are more preferred than others.

The diphenyl and ditolyl sulfones are particularly attractive anti-plasticizers because they are relatively easy to prepare from inexpensive raw materials, have melting points in the desirable range of 20°-200°C, are essentially free from odor, have high boiling points, and are chemically very stable.

Another group of compounds useful in the present invention are substituted benzenes having the formula II:

wherein q is an integer of 1 to 6 and

Z is a member selected from the group consisting of Cl, Br, NH₂, NO₂, COOH, OH, carbonyl having 1 to 8 carbon atoms, alkyl having 1 to 8 carbon atoms, alkoxy having 1 to 8 carbon atoms, phenyl, phenoxy and naphthyl, said Z's being the same or different when q is greater than 1.

Where added fire resistance is needed, in a fiber bonded product, halogenated aromatics may be employed, or aryl phosphates or phosphines. For example, the chlorine containing compound a, a, 2,3,4,5,6 heptachlorotoluene, when used with a polyvinyl chloride (PVC) resin maintains a high chlorinated organic level which, in conjunction with about 10-20 phr of antimony of antimony oxide, gives excellent fire resistance properties to many fiber batts and pads. Similarly, tetra bromo diphenylene oxide may be used as an anti-plasticizer and fire retardant.

The effect on melting point of mixing two antiplasticizer compounds with a resin may be seen in the following table, in which the resin is a pipe-grade PVC homopolymer, one compound is phthalic anhydride, and the second compound is another material. The ratios used are 1:1:1. Compound Amount Melting Point Lowered

(w/phthalic anhydride)

Benzoin

Benzoic Acid

Benzophenone

Acenaphthene

(PNCl₂)₃

Phenoxy Phosphazine Biphenyl Tribenzylamine Diphenyl Sulfone Alpha Naphthol Tetrachlorophthalic anhydride 2,4 Dinitrohydroxybenzene Diamino Diphenylmethane

Any thermoplastic resin can be employed as long as the resin is soluble in the compound used. The useful thermoplastic resins can be addition polymers or condensation polymers. The thermoplastic resins can be homopolymers, copolymers or interpolymers of three or more monomers. The thermoplastic resins can be random, block, or graft polymers. Resins to be useful in the present invention are selected primarily with reference to their physical properties. It is believed that the resins in the present invention undergo no chemical reactions Therefore, the chemical composition of the resins is completely unimportant in the present invention. Thermoplastic resins of all chemical compositions can be employed. Suitable addition polymers include those of ethylene, propylene, acrylonitrile, acrylic acid, ethyl aerylate, methyl methacrylate, styrene, vinyl chloride, vinylidene chloride, dibutyl maleate and other vinyl monomers. Other resins suitable in the present invention include polyesters such as polyethyleneterephthalate. The polyesters can be produced by condensation polymerization or by the autopolymerization of cyclic esters or by any other known means.

Polyamides useful as resins in the present invention include nylon 6 and nylon 66. Polycarbonate resins, polysulfone resins, ionomer resins, polyimides, and phenylene oxide resins may all be employed in this invention.

In the plastic alloy, the weight ratio of the compound (s) to the resin can vary widely but is generally in the ratio of 1:2 to 10:1 and preferably 1:1 to 4:1.

The plastic alloy may be prepared by mixing and melting together the resin and the anti-plasticizer compound, after which the solution of resin in anti-plasticizer is cooled to solid form, crushed to approximately sand-like consistency, and thereafter, air milled to approximately 10-15 micron size particles. Alternately, the final alloy particles may be prepared by polymerizing the resin from monomer which is dissolved in the anti-plasticizer. In this case the temperature, stirring, catalyst, emulsifying and suspending agents are adjusted by techniques well-known .to those skilled in the art so that the resulting particles of resin alloy, after being centrifuged and dried, are in the desirable size range of 10 to 15 microns and need no further grinding or milling

The plastic alloy is applied to the web in an amount sufficient to function as an adhesive and generally in a weight ratio of the plastic alloy to the fibers of 1:99 to 40:60 and preferably 3:97 to 35:65. The plastic alloy particles generally have a size range of from 1 to 100 and preferably from 6 to 25 microns and ideally 8 to 12 microns. Smaller sizes than about 5 microns tend to agglomerate into larger clumps and to flow poorly. These smaller particles are also undesirably respirable. Larger sizes than 12 microns and particularly sizes larger than 25 microns are increasingly inefficient fiber binders and yield soft, weak batts because of the smaller numbers of bonding sites which they provide in the fiber assembly.

A wide variety of fibers are useful in the present invention, including both natural and synthetic fibers. Natural fibers include those of cotton, wool, linen, hair, jute, and hemp. Synthetic fibers include those of glass, mineral wool, polyester, nylon, acrylic, polypropylene and rayon. In fact, any fiber or mixture of fibers in which the fiber may be new, unused fibers (virgin fibers) or may be waste fibers reclaimed from garment cuttings, fiber manufacturing, or textile processing, and which do not melt or decompose at temperatures below the melting point of the plastic alloy can be employed. The preferred fibers are those having a denier of 1 to 22, although finer or coarser fibers can be used.

In one embodiment of the present invention, a fiberous web is first contacted with the plastic alloy, forming a horizontally disposed thin, planar assembly of fibers which is then formed into a batt. As used herein, a batt is a plurality of webs, as well as, similar structures produced by air-lay methods.

The individual fibers of the batt, formed as described above, are then bonded at their intersection by melting and refreezing the plastic alloy particles.

The batt is heated to a temperature above the melting point of the plastic alloy but below the scorching or melting point of the fibers and generally at a temperature of 121° to 204°C (250° to 400°F) and preferably 149° to 193°C (300° to 350°F). At much higher temperatures, the fibers are adversely affected. The heating is conducted for a time sufficient to effect the desired melting of the plastic alloy which generally occurs within a period of from 1/2 to 20 minutes and preferably from 1 to 5 minutes . The batt is then cooled in air whereupon the melted plastic alloy is refrozen. Referring now to the drawings and in particular to Figure 1, there is shown an apparatus 10 useful for practicing the process of the present invention. The apparatus 10 comprises an opener or a garnett 11, a particle dispenser 12, a cross-laying mechanism 13 and, as shown in Figure 2, an oven 14. The garnett 11 comprises an inlet chute 18 adapted to feed bulk fibers to the rotating drum 19 of the garnett 11. The garnett 11 is also provided with a plurality of toothed rolls 21, 22, 23, 24, 25 which together with the teeth (not shown) on the drum 19 take bulk fibers 20 and convert them to a web which adheres to the drum 19. The web adhering to the drum 19 is transferred to the drum 28 where it is removed by a comb 29. The web 31 that is now only between 1 and 100 fibers thick and is barely self-supporting enters the particle dispenser 12. While in the particle dispenser 12 the web 31 is contacted with particles 33,34 of plastic alloy. Details of the structure and function of the particle dispenser 12 are described in U.S. Patent 4,363,680 issued December 14, 1982. Another method of application which performs satisfactorily involves contacting the fibers with the resin after the fibers have been opened and loosed from the compressed bale and at the stage when they are entrained in an air stream and prior to being deposited on a screen or in the off-take slot of an air-lay system for producing non-woven batts. Air-lay systems of this type are well known in the trade under the names Schirp, Rando, Web, DOA, and others.

In the process illustrated here, simply as an example, the web 39 then goes to the conveyor 41 and thence to the conveyor 42. In a manner well known in the art, the lower end of the conveyor 42 is attached to a traveller 43 which moves back and forth on the track 44.

The conveyor 42 is positioned above and at right angles to other conveyor 45. The apparatus is adjusted such that the speed of the conveyor 42 is several times faster than the speed of the conveyor 45. By virtue of this arrangement, the web 39 is cross-laid back and forth on the conveyor 45 thus forming an unheat-treated batt 47. The unheat-treated batt 47 passes into a curing oven 14 supported by a foraminous belt, or in some cases between foraminous belts 49 and 50. (See Figure 3). In the oven 14, the particles of plastic alloy melt and thereby bind the fibers together. As shown in Figure 3, the oven 14 is provided with heating means 52 in which temperature can be controlled by a thermostat 53. The oven 14 is also provided with air circulating means not shown that causes the air to circulate in the direction shown by the arrows 55 and 56. The resultant product is the final heat-treated batt 58.

Figure 4 illustrates two methods of introducing the powdered resin alloy in an air-lay system for producing bonded fiber batts. In this system fibers are opened in a feeder device 111 and fed by appropriate means to a reserve hopper 112. The opened tufts of fiber in the hopper are fed through rolls 113 and then between a roll and a nose bar 114 where they are plucked free by a rapidly turning roll with saw-type teeth 115. These more fully opened fibers are entrained in an air stream and then separated from the air stream on two rotating perforated cylinders 116, thus forming a batt in the gap between these cylinders. This batt is subsequently fed again between feed rolls and a nose bar 117 and once again plucked by a saw-toothed lickerin roll 118. The fibers are then formed a second time into a batt by the same process of condensing them on two perforated rolls 119 so that as these rolls turn the batt 110 forms in the gap between them.

In the air-lay process described above, the powder may be added in the first airstream 121 which carries the fibers to the first pair of perforated rolls, on to the reserve hopper (indicated in 111 and 112) or may be applied from a suitable hopper to the top of the first batt at point 122. If the latter point of application is chosen, the mixing of the powdered resin alloy occurs when the batt is again reduced to loose fibers and reformed into a batt at the second pair of perforated rolls. After the final batt is formed, it is cured in an oven and the resin alloy is frozen in a cooler as described in the earlier example.

The invention may be understood by reference to the following non-limiting examples. These examples are designed to teach those skilled in the art how to practice the invention and represent the best mode contemplated for practicing the invention. Unless otherwise specified, all parts and percentages are by weight.

Example 1

This example illustrates the synthesis of a plastic alloy useful in the present invention.

The following quantities of the following ingredients are combined as indicated.

Item Ingredient Quantity (grams)

A Benzoin 200

B PVC homopolymer resin 100

(pipe grade)

Items A and B are dry blended in powder form in a high intensity mixer for 5-10 minutes at 160°C whereupon item A melts and item B dissolves in it to form a single phase. The mixture of items A and B is then cooled, removed from the mixer and, ground to an average particle size of 12 microns. The resultant material is a particulate plastic alloy which has a melting point of approximately 140°C and is useful in the present invention. In contrast, the PVC homopolymer by itself does not melt but begins to decompose at 215°C and has no use as a fiber binder. Example 2

In this illustration the following quantities of the following ingredients are combined as indicated.

Item Ingredient Quantity (grar A Benzoin 100 B Benzoic acid 100 C PVC homopolymer resin 100

These items are mixed in the same manner as in Example 1. However, in this case the melting point of the resulting plastic alloy is 126°C, 14°C lower than in Example 1 because the use of the two crystalline compounds together may result in a lower melting point than with either used alone.

Example 3

In this example 100 grams of a polyvinyl chloride/-polyvinyl acetate (PVC/PVA) resin having a content cf 3% PVA and 97% PVC and a melting point (as determined microscopically) of 195°C is dissolved in 100 grams of a 50:50 mixture of benzoi: and phthalic anhydride. The melting point of the resulting alloy is 135°C.

Example 4

Using a single compound, tribenzylamine, the melting point of a copolymer of PVC and di-butyl maleate (DBM) containing 3% DBM is reduced from 205°C to 140°C when the resin is dissolved in an equal amount of the compound. Examples 5-9

Ratio Compound Melting Point

Ex. Resin Compound To Resin Resin Alloy

5. Polyester, from Benzoin & 2:1 255°C 145°C terephthalic acid Triphenylamine & ethyleneglycol 1:1 6. PVC homopolymer Tribenzylamine 2:1 220°C 125°C (pipe grade) Triphenylamine 1:1

7. PVC homopolymer Benzoin 2:1 220°C 135°C (pipe grade) Phthalic anhydride 1:1

8. Polyamide Benzoin 2:1 255°C 142°C (nylon 66) Tribenzylamine 1:1

9. PVC homopolymer Benzoin 2:1 220°C 135°C (pipe grade ) Tetrabromo diphenyl oxide

1:2

Examples 10-17

In these examples, a pilot production line was set up to produce a batt or pad from a mix of recycled polyester and cotton fibers. The line speeds and settings were adjusted to make this pad 1" thick and with a density of 4 oz. per square foot. The resin feeder was set to apply 15% resin, based on the weight of the fiber used. This basic set-up was used with four different resins in runs 10, 11, 12 and 13 as charted below, and with four different resin alloys 14, 15, 16 and 17 also as described below. The oven temperature was fixed at 350 °F for all eight trial runs.* The results were as follows: * If the oven had been operated at 450°F instead of 350°F, the properties of the batts produced in runs 10, 11 and 13 would have been much improved, since this temperature would have been high enough to cure the resins employed in those runs. However, as noted previously, the use of the high curing temperatures has many disadvantages which the present invention avoids.

Although the invention has been described in considerable detail with reference to certain preferred embodiments thereof, it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described above and as defined in the appended claims.

Claims

What is Claimed is:

1. A process for bonding fibers comprising the steps of: I. contacting the fibers with a particulate plastic alloy comprising:

A. a compound; and

B. a thermoplastic resin; wherein the compound:

(1) is a crystalline organic compound at standard temperature and pressure;

(2) has a melting point of 20 to 200°C at atmospheric pressure;

(3) has a boiling point of 100 to 450°C at atmospheric pressure; and

(4) is a solvent for the resin; and then II. heating the mixture of plastic alloy and fibers to melt the plastic alloy and bind the fibers.

2. A process for bonding fibers comprising the steps of: I. contacting the fibers with a particulate plastic alloy comprising:

A. a compound; and

B. a thermoplastic resin; wherein the compound:

(1) is a crystalline organic compound at standard temperature and pressure;

(2) has a melting point of 20 to 200°C at atmospheric pressure;

(3) has a boiling point of 100 to 450°C at atmospheric pressure;

(4) is a solvent for the resin;

(5) has a vapor pressure of less than 2mm of mercury at 100°C;

(6) is free of objectionable odors;

(7) contains at least one benzene ring in its chemical structure; and

(8) has a solubility in water of less than 10 mg per liter measured at 20°C; and

II. heating the mixture of plastic alloy and fibers to melt the plastic alloy and bind the fibers.

3. The process of Claim 1 wherein the plastic alloy comprises at least two compounds.

4. The process of Claim 2 wherein the compound is a substituted benzene having the formula:

wherein q is an integer of 1 to 6 inclusive and

Z is a member selected from the group consisting of

Cl, Br, NH₂, NO₂, COOH, OH, carbonyl having 1 to 8 carbon atoms, alkyl having 1 to 8 carbon atoms, alkoxy having 1 to

8 carbon atoms, phenyl, phenoxy, and naphthyl; said Z's being the same or different when q is greater than 1.

5. The process of Claim 2 wherein the compound contains a fused aromatic ring.

6. The process of Claim 2 wherein the compound comprises a member selected from the group consisting of triphenyl phosphine, phosphonitrilic ester trimers, phosphonitrilic ester tetramers and phenoxy derivatives of phosphonitrilic ester trimers and tetramers.

7. The process of Claim 2 wherein the compound comprises an N-substituted urea in which at least one of the substituents contains a member selected from the group consisting of benzene and fused aromatic rings.

8. The process of Claim 2 wherein the compound comprises a member selected from the group consisting of benzil, benzoin, fluoranthene, fluorene, phenanthridene, thanthrene, thiopanthrene, xanthene and xanthone.

9. The process of Claim 2 wherein the compound comprises a member selected from the group consisting of diphenyl sulfone and ditolyl sufone.

10. The process of Claim 1 wherein the resin is polyvinylchloride.

11. The process of Claim 1 wherein the resin is a copolymer of vinylidene chloride and one or more ethylenically unsaturated monomers copolymerizable therewith.

12. The process of Claim 1 wherein the resin is a copolymer of vinylidene chloride and dibutyl maleate.

13. The process of Claim 1 wherein the weight ratio of the compound to the resin is 1:10 to 10:1.

14. The process of Claim 1 wherein the weight ratio of the plastic alloy to the fibers is 1:99 to 50:50.

15. The process of Claim 1 wherein the plastic alloy particles have a size range of from 1 to 200 microns.

16. The process of Claim 1 wherein the plastic alloy particles have a size range of from 6 to 30 microns.

17. The process of Claim 1 wherein the plastic alloy particles have a size range from 8 to 12 microns.

18. The process of Claim 1 wherein the plastic alloy has a melting point of 100 to 210°C.

19. The process of Claim 1 wherein the steps are practiced in the order recited.

20. The process of Claim 1 wherein the temperature in Step II is between 100 and 232°C.

21. The process of Claim 1 wherein the heating is conducted for a period of from 1/2 to 20 minutes.

22. A dry process for producing a fiberous batt of high cohesive strength comprising in sequence the steps of:

I. forming a horizontally disposed, thin, planar web of fibers having a fiber denier from 1 to 22, said web being from 1 to 100 fibers thick; and then II. contacting the web with particles of a plastic alloy while the web is in contact with and supported by a moving conveyor to form a mixture of alloy and fibers; wherein the plastic alloy comprises a compound and a thermoplastic resin; and wherein the compound:

(1) is a crystalline organic compound at standard temperature and pressure;

(2) has a melting point of 40 to 150°C at atmospheric pressure;

(3) has a boiling point of 150 to 450°C at atmospheric pressure;

(4) is a solvent for the resin; and

A. wherein the weight ratio of the plastic alloy to the fibers is 3:97 to 35:65;

B. wherein the plastic alloy particles have a size range of 6 to 25 microns;

C. wherein the plastic alloy has a melting point of 135 to 190°C; and

D. wherein the weight ratio of compound to resin is 1:10 to 10:1; and then

III. forming the web into a batt by laying the web transversely back and forth on a moving belt such that the batt comprises a plurality of webs; and then

IV. heating the batt to a temperature of 163 to 218°C for a period of 1 to 5 minutes while the batt is being passed through an oven and then cooling the batt between two parallel foraminous belts while cool air is forced through the batt; thereby producing a fiberous batt of high cohesive strength.

23. A fiberous batt, the individual fibers of which are bonded at their intersection by melted and refrozen particles of a plastic alloy comprising a compound and a thermoplastic resin wherein the compound:

(1) is a crystalline organic compound at standard temperature and pressure;

(2) has a melting point of 40 to 150°C at atmospheric pressure;

(3) has a boiling point of 150 to 450°C at atmospheric pressure; and

(4) is a solvent for the resin.

24. The fiberous batt of Claim 23 wherein the plastic alloy comprises a mixture of at least two compounds .

25. A dry process for producing a fiberous batt of high cohesive strength comprising the steps of:

I. forming the batt by conventional air-lay equipment; II. contacting the surface of the batt with particles of a plastic alloy; III. reducing the batt to fiber tufts of opened fiber and simultaneously mixing the plastic alloy particles with the opened fibers of the batt; IV. reforming the batt again by air-lay methods in which the batt is formed between perforated cylinders; V. heating the batt by passing hot air through the batt in an oven; and VI. cooling the batt between foraminous belts by passing cool air through the batt and freezing the plastic alloy to produce a batt with high cohesive strength; wherein the plastic alloy comprises a compound and a thermoplastic resin; and wherein the compound: (1) is a crystalline organic compound at standard temperature and pressure;

(2) has a melting point of 20 to 180°C at atmospheric pressure;

(3) has a boiling point of 100 to 450°C at atmospheric pressure;

(4) is a solvent for the resin to form a mixture of alloy and fibers.

26. The process of Claim 25 wherein the plastic alloy is entrained in the airstream which forms the batt either in Step I or in Step IV.

27. The process of Claim 25 wherein the plastic alloy comprises at least two compounds.

28. A plastic alloy comprising:

A. a compound; and

B. a thermoplastic resin; wherein the compound has the formula:

wherein m is an integer of 0 or 1, n is an integer of 0 to 5 inclusive, p is an integer of 0 to 5 inclusive, R is a member selected from the group consisting of S, SO, SO₂, O, CH₂, CHOHOCHOH, CHOHO, CO, NH, COCO, NR' , CHR', CHR'O and CR'R" wherein R' and R" each independently represent a lower alkyl group having 1 to 8 carbon atoms or a phenyl group, and

X and Y are each independently selected from the group consisting of Cl, Br, NH₂, COOH, OH, carbonyl having 1 to 8 carbon atoms, alkoxy having 1 to 8 carbon atoms, alkyl having 1 to 8 carbon atoms, phenyl, phenoxy and naphthyl, said X's being the same or different when n is greater than 1 and said Y's being the same or different when p is greater than 1; and wherein the compound:

(1) is a crystalline organic compound at standard temperature and pressure;

(2) has a melting point of 20 to 180°C;

(3) has a boiling point of 100 to 450°C at atmospheric pressure; and

(4) is a solvent for the resin.

29. A method for producing the plastic alloy of Claim 28 which comprises dissolving the thermoplastic resin in the compound and thereafter cooling, crushing, and milling the resultant alloy to a dry powder with particle size between 5 and 100 microns, the ratio of compound to thermoplastic resin being from 1:2 to 10:1.

30. A method for producing the plastic alloy of Claim 28 which comprises dissolving or dispersing the resin monomer in the compound and thereafter polymerizing the resin in said compound to produce the plastic alloy in particle sizes from

5 to 100 microns.

31. The plastic alloy of Claim 28 in which the plastic alloy comprises one or more thermoplastic resins and one or more compounds.

32. The process of Claim 2 wherein the plastic alloy comprises a compound of the formula:

wherein m is an integer of 0 or 1, n is an integer of 0 to 5 inclusive, p is an integer of 0 to 5 inclusive, R is a member selected from the group consisting of S, SO, SO₂ , O, CH₂ , CHOHOCHOH, CHOHO, CO, NH, COCO, NR', CHR' , CHR'O and CR'R" wherein R' and R" each independently represent a lower alkyl group having 1 to 8 carbon atoms or a phenyl group, and

X and Y are each independently selected from the group consisting of Cl, Br, NH₂ , NO₂ , COOH, OH, carbonyl having 1 to 8 carbon atons, alkoxy having 1 to 8 carbon atoms, alkyl having 1 to 8 carbon atoms, phenyl, phenoxy and naphthyl , said X's being the same or different when n is greater than 1 and said Y's being the same or different when p is greater than 1.

33. The fiberous batt of Claim 25 wherein the plastic alloy comprises a compound of the formula:

wherein m is an integer of 0 or 1, n is an integer of 0 to 5 inclusive, p is an integer of 0 to 5 inclusive, R is a member selected from the group consisting of S, SO, SO₂, O, CH₂ , CHOHOCHOH, CHOHO, CO, NH, COCO, NR' , CHR' , CHR'O and CR'R" wherein R' and R" each independently represent a lower alkyl group having 1 to 8 carbon atoms or a phenyl group; and

X and Y are each independently selected from the group consisting of Cl, Br, NH₂ , NO₂ , COOH, OH, carbonyl having 1 to 8 carbon atoms , alkoxy having 1 to 8 carbon atoms, alkyl having 1 to 8 carbon atoms, phenyl, phenoxy and naphthyl, said X's being the same or different when n is greater than 1 and said Y's being the same or different when p is greater than 1.