DE2461869A1 - FIBER NON-WOVEN FABRIC AND METHOD FOR MANUFACTURING IT - Google Patents

Description

24618 & 9

DR. MÜLLER-IS ORS DIPL. ING. GROENING

DIPL.-CHEM. DR. DEUFEL DIPL.-CHEM. DR. SCHÖN

DIPL.-PHYS. HERTEIi

PATENT LAWYERS

Y / Y. 10-19

Johnson & Johnson 501 George Street New Brunswick, N.J. UNITED STATES.

Nonwoven fabric and process for its manufacture.

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The invention relates to solid, absorbent, abrasion-resistant, bonded nonwovens and a process for their manufacture.

In particular, the invention relates to such fiber nonwovens that are suitable for cleaning and wiping purposes, urü a method of binding them, through which the strength, Improved absorption and abrasion resistance properties over those of conventional bonded nonwovens will. The invention also relates in detail to solid, absorbent and abrasion-resistant wiping materials for absorbing purposes and holding oily or oily substances such as lubricants, oils and fats and a method for their production.

Bound fiber nonwovens have so far been used in numerous applications have been used, such as for wiping and cleaning cloths, and they are generally used in proven to be satisfactory and economically acceptable in the industry. However, in general there is always the Desire to improve the properties and characteristics of such bonded nonwovens, and at In the specific application mentioned, there has always been a desire to improve the strength and absorption properties Abrasion resistance properties of the fabrics without loss of other desirable properties.

These demands are made more so when bonded non-woven fabric, the relatively short fibers, such as wood pulp, cotton linters and the like contained. Slipping out their use in general, the strength and abrasion resistance due to the low upper flat integration of the short fibers, their tendency for frictional and affect their generally low strength due to their short length.

It has been shown that. these requirements can be met by a solid, absorbent, abrasion-resistant nonwoven fabric, which is characterized by a fiber layer made from (1) from. ο up to about 75 percent by weight of long-spun staple fibers and (2.) 100 to about 25 percent by weight of short staple fibers as a further length "as" the 1 * 1 * 9spun

Staple fiber, wherein the fiber layer is bound by (1.) primary intermittently spaced printed pattern binder areas extending substantially from one surface to the other surface and (2) secondary, intermittently spaced printed pattern binder areas which are predominantly provided on the surface of the fiber layer and lie between the primary binder areas.

In the following, preferred exemplary embodiments of the invention are explained in more detail with reference to the accompanying drawings.

Fig. 1 is a simplified, schematic

Flow chart to illustrate an embodiment of the invention Procedure;

Figure 2 is a simplified, schematic flow diagram illustrating another Embodiment of the method according to the invention;

Fig. 3 shows an idealized Teifc cross-section . a bonded · nonwoven fabric that is made by one of the methods illustrated in Figures 1 and 2, wherein the cut is laid along the longitudinal or machine direction of the nonwoven fabric is.

In Fig. 1, a fiber treatment apparatus 1o is to be formed a fiber web of overlapping and intersecting Fibers shown. The particular type of device is not of particular importance to the present invention. There are carding machines, air-laying and wet-laying devices, among other things such as Garnetts, double tearing rollers, Rando-. Conveyors and Rando Nonwoven Devices, Papermaking

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machines etc. into consideration.

The fibers used

The fibers used can be; from 'o to about 75 percent by weight long fabric staple fibers having an average length of at least about 12.7 mm up to about 38 mm and even above, i.e. up to about 76 mm as required be. Such fibers include natural fibers, especially cotton, and synthetic or man-made ones Fibers such as rayon (peyon), polyamide nylon 6 and 66, polyester, polyolefin, polyacrylic, modacrylic, cellulose derivatives, Polyvinyl alcohol and similar fibers. Which have synthetic or man-made fibers denier from about 1 to about 5, although higher deniers of up to 10 or 15 can be useful in special circumstances.

Furthermore, short fibers such as wood cellulose (wood pulp), cotton linters and the like. Or, synthetic or man-made fibers in short lengths below 12.7 mm or 6.35 mm in proportions of about 25 percent by weight up to 100 percent by weight can be provided. Such fibers have an average length of less than about 12.7 mm and usually less than 6.35 mm, and they can have an average length of only about 0.4 mm and even less.

In the present context the Worf'Fiber "is used in its normal technical or lexical sense, as it is defined in ASTM regulation D 123-72. ¹ Fiber is a general term for different types of things (natural and man-made) More precisely, a fiber is an entity characterized by having a length of at least 100 times its diameter or width and very often more than about 160 times its diameter or its width. _t

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Primary bond

The fiber web W is after production in the fiber treatment device 1o if desired fed to the dehumidifier or the humidity control device 12, through which the moisture content of the web is adjusted to a desired range. The fiber web with the controlled moisture content is then transferred to a conventional nonwoven binder 14 which is a primary Binder B in intermittently spaced printing patterns on the fiber web W in the form of limited binder surfaces or binder areas 16 (Fig. 3) applies. Examples of such primary, intermittently spaced-apart binder print pattern areas or areas are cross tightening patterns (U.S. Pat. 2,7o5,687), dot or ring patterns (U.S. Pat. 2,7o5,688), diamond patterns (Fig. 3, U.S. Pat. 2,7o5,498), torpedo patterns (U.S. Pat 3oo9.8? 3) etc.

As shown in Fig. 3, the primary binder B is in this way under controlled nip pressure and among others Pressure rolling conditions and applied from relatively deeply engraved recesses on the pressure roller, so that relatively larger amounts of binder to be applied to the fiber web, so that the binder in perfect Way, the fiber web W penetrates directly and completely from one surface to the other surface and the longer one spun staple fibers and coherence and strength tei the finished nonwoven fabric is created without the Softness, the grip properties or the formation of wrinkles in undesirably affected. The surface coverage such a primary binder, which starts at the beginning is brought, is in the range of about 5 to 5o% of the Ge. entire surface of the fiber web, with about 1o to about 35% are preferred.

The binders used

Those as primary binders and other binders described later binder resins used can be selected from a relatively large group of resins, in particular resins with syn-

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of thetic origin, and they are usually found in the form of aqueous »dispersions. There can be polymers and mixed polymers of polyvinyl esters, polyvinyl halides such as plasticized and unplasticized polyvinyl chloride, Polyvinyl chloride and other plastisols, polyvinyl esters such as plasticized and unplasticized polyvinyl acetate, Polyacrylic resins such as polyethyl acrelate and polybutyl acrelate, Polymetacrylic resins, polyolefin resins, such as ethylene-vinyl acetate and ethylene vinyl chloride, polyamide resins, synthetic Rubber resins such as styrene-butadiene, polyvinyl alcohol and other aqueous solutions etcj. be.

It is particularly advantageous to use resin binders with controlled Migratory traits that have a low tendency to migrate. Examples of such resins are in US Pat U.S. Patent 3,7o6,595 indicated.

The amount of primary binder addition ranges from about 1 to 2 percent by weight, but usually from about 6 to about 3o weight percent, and preferably about 7 to about 15 weight percent on a dry weight basis based on that Dry weight of the bonded nonwoven fabric.

As shown in Fig. 3, limited bound areas or areas of binding 16 are provided which intermittently through Areas 18 are kept at a distance that do not come into contact with the primary binder and bound by this are. In these areas 18 there is a relatively large number of short fibers with a length of less than the distance between two bound binder areas 16 which are exposed to danger in the unbound and unsecured state are to slip out and during use and especially during a rubbing process or application getting lost from abrasive forces.

Secondary bond

The fibrous web becomes the primary binder applied to it a conventional binding device 2o for nonwovens adjoining, which has a secondary binder B 'in an inter-

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centering, closely spaced print patterns

the fiber web applies. . ·

Examples of such secondary, intermittently closely spaced printed pattern binder areas are diamond patterns (Fig. 3, U.S. Patent 2,7o5,498) and diagonal and wavy line patterns (Figs. 1 to 4, U.S. Patent 3oo9,822). Fine or Miniature dot patterns as applied by engraved cells can also be used.

As shown in Fig. 3, the secondary binder B 'is under controlled nip pressure and under other pressure rolling conditions

as

from flat engraved recesses on the pressure roller applied, "whereby relatively smaller amounts of binder be recorded for application to the fiber web, so that the binder does not substantially soak the fiber webs, but above all is primarily and predominantly on their surface. In this way the binder binds the surface fibers and especially the short fibers in "the" areas that have not come into contact with the primary binder.

This binding of surface fibers through the secondary binder prevents slipping out and loss of surface fibers and increases resistance to friction and abrasion. Of course, the secondary binder does not contribute significantly to the strength of the finished nonwoven fabric, nor does it significantly affect the softness, the feel and the folding properties. The total. The surface coverage by such a secondary binder, as it is initially applied, is in the range from approx. 90% of the total surface of the fiber web. The addition of secondary binders is very small when only one side is viewed and is in the range of about 0.2, but usually about 2 to about 10 weight percent on a dry weight basis of the finished, dry nonwoven fabric. Alongside It should be noted that the secondary binder not only affects the areas between the primary binder areas, but also is applied to the primary binder areas themselves.

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The fibrous web with the primary binder and the secondary binder on only one side can then be passed to the humidity control device 22 are supplied, which are formed for example by a heated oven or by heated drying containers and brought to a desired moisture content if desired or necessary.

The fiber web is then turned around rotatable pulleys

24 and 26 and passed through the conventional nonwoven binding device 28, the is essentially identical to the secondary fibrous nonwoven binding device 2o except that the binder B 'is on the other side of the fiber web is applied. The binder swatches, surface covering, binder 'dry additive etc. take place in the form and in the manner as well as in the area which was previously determined in relation to the secondary binder B ' has been described.

The fibrous web then passes through conventional drying equipment 3o, like a heated oven or heated drying container whose temperature is increased, "so that the fiber web dried and the applied binder, if necessary,

dried and cured.

The dried, bonded nonwoven fabric then arrives a winder that winds the nonwoven fabric into a finished roll 32.

The modification according to FIG. 2

A modification of the inventive concept is shown in FIG. 2, in which the reference numbers and labels _/ the elements correspond to FIG. 1, with the same reference number added with an "a". FIG. 2 shows a fiber treatment device 1oa for producing a fiber web Wa which is basically the same as that of FIG. ,.

The fiber web Wa becomes a dehumidifying or dampening

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Activity control device 12a passed through which the moisture content is adjusted to a desired range. The wet web becomes, then, a conventional nonwoven fabric binder 14a, 2oa, which applies essentially simultaneously: (1.) a relatively deep, intermittently spaced, primary binder printing pattern on the fibrous web in the form of limited. Binder surfaces or binder areas as well as (2.) - a relatively flat, intermittently arranged at a close distance, secondary binder pressure pattern in the areas between the primary intermittently spaced binder areas. These printed pattern binders and binder areas and binder areas have already been described above in connection with FIG. 1 been.

According to Fig. 2, the engraved pressure roller (gravure roller) that dips into the binder dispersion and picks up binder and puts it on the underside '. the fiber web transmits, relatively deep engravings and relatively shallow engravings to accommodate larger and smaller amounts of binder and for the respective application of the deeply penetrating primary binder to the fiber web as well as the thin, less penetrating one Binders on the fiber material.

This single printing process is carried out with the two separate printing processes in the binding devices 14 and 2o according to FIG comparable, and the binding devices 14a and 2oa according to FIG exercise the two functions essentially simultaneously, the two separate binding devices 14 and 2o according to Fig. 1 are exercised.

The fiber web then passes over rotatable deflection rollers

24a and 26a and then through a conventional 'nonwoven fabric binder 28a which has a secondary, intermittently close together! Legends binder on the back the fiber web applies.

The primary and the two secondary resin binders that are on the fibrous web are usually chemically the same.

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However, different resin binders can be used in special circumstances be used.

The heating, drying and curing of the fiber web and the binder q, uf the fiber web takes place in conventional drying devices 30a, and then the dried, bonded nonwoven fabric is fed to the winding device and made into a finished one Roll 32a wound up.

The invention will be further illustrated in greater ¹ x accuracy by the following specific examples. While these examples may describe in detail some of the more specific features of the invention, they are intended to illustrate the invention and not to limit it.

Example I.

The device shown in FIG. 1 is used. A disordered, Air-laid, isotropic fiber web is made from 90 percent by weight wood pulp fibers and 0 percent by weight polyester fibers made with 1 1/2 denier and 38.1 mm fiber length. The fiber web is rearranged by a fluid-based device, as shown in Fig. 7 of US Pat. No. 2,862,251. The fiber web we are treated with water and converted into fiber bundles and fleece openings, as described in the cited patent.

The wet fiber web is then passed through a device applying the primary binder. The binder is an aqueous dispersion with 2o% of a self-crosslinking Polyaethylacrelat. The primary, intermittent print pattern of the binder that is applied is a 1.57 diamond pattern Lines per cm (4 lines per inch) and a line width of 0.6 mm (0.024 inches). .

The primary binder penetrates the wet fibrous web and creates coherence and strength in the finished fibrous nonwoven. One subsequent examination shows that the primary binder penetrates essentially completely through the fibrous web from one surface extends to the other. The addition of binder is 7.5%

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Dry weight, based on the dry weight of the finished product, bonded nonwoven fabric.

The fiber web is then secured by a pair of the; - '2. "binders. Applicators' devices that put the binder on both sides of the fibers in two separate steps raise. The binder is an aqueous dispersion with 20 percent by weight of a self-crosslinking polyethylacrelate. The applied secondary intermittent print pattern is a 9 lines per cm (23 lines per cm) diagonal line pattern Inches) and a line width of 0.45mm (0.018 inches).

The secondary binder binds the surface fibers of the fiber web and prevents it from slipping out. of the fibers in the event of friction or abrasion. The addition of binder on each side is 3.5% Dry weight, based on the dry weight of the finished bonded nonwoven fabric.

The fiber web carrying the binder is then continued, dried, cured and wound up on a supply roll when dry. It has a basis weight of 106.66

g / m. (grain weight of 1415 grains / sq.yd.) and is economical Can be used as a wipe.

Example II

The process steps of Example 1 are carried out essentially in the manner described above, with the exception that the primary print pattern is a crosshatch-shaped, intermittently spaced print pattern is like it shown in Fig. 3 of U.S. Patent 2,7o5,687.

The results are generally similar to those of Example 1 comparable.

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Example III

The procedural steps of Example I are essentially carried out in the manner described above, with the exception that the primary print pattern is an intermittent im The spaced cross-hatch print pattern is as shown in Fig. 5 of U.S. Patent 2,7o5,687.

The results are generally comparable to those of Example I.

Example IV

The process steps of Example I are carried out essentially in the manner described above, with with the exception that the primary ^ Dtaack pattern is an intermittent spaced ring print pattern as shown in Fig. (code 11-C-1) of US Pat. No. 2,7o5,688.

The results are generally comparable to those of Example I.

Example V

The process steps of Example I are carried out essentially in the manner described above, with except that the primary print pattern is an intermittently spaced torpedo print pattern. is like it is shown in Fig. 6 'of U.S. Patent 3,009,823.

The results are generally comparable to those of Example I.

Example VI

The process steps of Example I are essentially performed in the manner described above, except that the secondary, intermittent printing pattern, the is applied, a diagonal line pattern is 6.3 Li-

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lines per cm (16 lines per target) and a line width of
o.45 Jtim (o, o18 inches).

The results are generally similar to those of Example I.
comparable. The resulting, bonded nonwoven appears somewhat softer and has better wrinkling and better grip properties. However, the abrasion resistance is somewhat lower.

Example VII

The process steps of Example I are followed essentially in the manner described above, except that the secondary, intermittent printing pattern, the
is applied, a diagonal line pattern with 9 lines per
cm (23 lines per inch) and a line width of 0.45 mm
(o, o18 inches) is.

The results are generally similar to those of Example I.
comparable. The resulting, bonded fiber nonwoven, however, appears to be somewhat less soft and has somewhat poorer wrinkling and grip properties. However, the abrasion resistance is better.

Example VIII

The process steps of Example I are carried out essentially in the manner described above, with the exception that the fiber mixture is changed to 25 percent by weight wood pulp fibers and 75 percent by weight rayon fibers
with 11/2 denier and 38.1 mm fiber length.

The results are comparable to those of Example I.

Example IX

The process steps of Example I are carried out essentially in the manner described above; with the exception, that the fiber mixture is changed to 75 percent by weight of wood pulp fibers and 23 percent by weight of rayon fibers

1.1 / 2 denier and 38/1 mm fiber length.

The results are comparable to those of Example I.

Example X

The process steps of Example I are carried out essentially in the manner described above, with the exception that the fiber mixture is changed to 85 percent by weight Wood pulp fibers and 15 percent by weight artificial silk fibers with 1 1/2 denier and 38.1 mm fiber length.

The results are comparable to those of Example I.

Example XI

The process steps of Example I are carried out essentially in the manner described above, with the exception that the fiber mixture is changed to 85% by weight of wood pulp fibers and 15% by weight of polyamide-nylon 6/6 1 1/2 denier fibers and 38.1 mm fiber length.

The results are comparable to those of Example I.

Example XII

For this example, the modified embodiment is the Device according to Fig. 2 is used. The basic process steps of Example I are essentially in the carried out in the manner described above, with the exception that the two conventional binding devices (14 and 2o) be replaced by a single, double-acting twin binding device (14a and 2oa) for applying the binder. As a result, a primary binder and a secondary binder are bound by a binding device in substantially the same manner. applied. The remainder of the procedure of this example is essentially described in Example I.

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The resulting, bonded nonwoven fabric is with that of Example I. It can be used economically as a wipe.

Example XIII

The procedural steps of Example I are carried out essentially in the manner described above - with the exception that the secondary, intermittent print pattern that is applied is a diagonal line pattern of 14.2 lines per cm (36 lines per inch) and a line width of 0.45 mm (0.018 inches

The results are generally comparable to those of Example I. The resulting, bonded nonwoven appears however, as somewhat less soft and has poorer wrinkling and grip properties. The abrasion resistance however, it is increased. . ,

Example XIV

The procedural steps of Example I are essentially as follows carried out in the manner described above, with the exception that the resin binder used is an aqueous latex with 55 percent solids content of a copolymer Is ethylene and vinyl acetate.

The results are generally comparable to those of Example I.

Example XV

The process steps of Example I are essentially carried out in the manner described above, with the exception that the resin binder is an aqueous latex having 50 percent solids a terpolymer of butadiene (46%), styrene (51%) and unsaturated a, b-carboxylic acid (2%).

The results are generally similar to those of Example. I. comparable.

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Although numerous specific examples of the invention have been described have been used, they are not intended to be limiting, not even with regard to the special features mentioned in the examples, to understand. Rather, numerous other equivalent features are included, as characterized in the claims are.

- patent claims -

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Claims (11)

Claims Strong, absorbent, abrasion-resistant nonwoven fabric, characterized by a fiber layer of (1) 0 to about 75 weight percent long-spun staple fibers and (2) 100 to about 25 weight percent short staple fibers with a shorter length than the long-spun staple fibers, the fiber layer is bound by (1) primary, intermittently spaced printed pattern binder areas (.16), the extend substantially from one surface of the fiber layer to the other surface and (2) secondary, intermittently spaced print pattern binder areas (18), which are predominantly on the Surface of the fiber layer are provided and lie between the primary binder areas (.1-6). 2. Nonwoven fabric according to claim 1, characterized by g e k e η η draw t that the addition of the primary binder is in the range of about 6 to about 3o percent by weight Dry weight basis based on the dry weight of the bonded nonwoven fabric. 3. Nonwoven fabric according to claim 1 or 2, characterized in that the addition of the secondary binder for each surface bound thereby in the range of about 2 to about 10 weight percent on a dry weight basis, based on the dry weight of the bonded nonwoven fabric. 4. non-woven fabric according to any one of the preceding claims, characterized e g ke nn ζ η et verifiable that the short fibers are pulp fibers. 5. Nonwoven fabric according to one of claims 1 to 3, characterized in that the short Fibers are cotton linters. . .509830 / 0842 - 18- 6. Nonwoven fabric according to one of the preceding claims, characterized in that the long-spun Staple fibers are nylon fibers. 7. nonwoven fabric according to one of claims .1 to 5, characterized in that the long-spun Fibers are polyester fibers. 8. Nonwoven fabric according to one of claims 1 to 5, characterized in that the long-spun fibers are rayon fibers. 9. Process for the production of a solid, absorbent, . abrasion-resistant nonwoven fabric, in particular according to a of the preceding claims, characterized in that a fiber layer is formed (1) ο to about 75 percent by weight long-spun staple fibers; and (2) 100 to about 25 percent by weight short Fibers with a shorter length than the long-spun staple fibers and that this fiber layer is bound with (1) primary, intermittently spaced, print pattern binder areas that are substantially extend from one surface of the fiber layer to the other surface and (2) secondary, intermittently im Spaced print pattern binder areas, which are predominantly on the surface of the fiber layer and between the primary truss areas. 10. The method according to claim 9, characterized in that the application of the primary binder and the two secondary binders is carried out in 3 separate steps. 11. The method according to claim 9 , characterized in that the application of the primary binder and the one secondary binder on a surface of the nonwoven fabric in one step and the application of the _s 50 9 8 3 0/0842 " -19 - second secondary binder carried out on the other surface of the nonwoven fabric in a second step will. 0/0; 84 Blank page