CA1159237A

CA1159237A - Absorbent composite towel material

Info

Publication number: CA1159237A
Application number: CA000391462A
Authority: CA
Inventors: Nicholas S. Newman
Original assignee: Kendall Co
Current assignee: Kendall Co
Priority date: 1980-12-08
Filing date: 1981-12-03
Publication date: 1983-12-27
Also published as: US4355066A

Abstract

ABSTRACT
An absorbent hydrophilic and oleophilic multipurpose composite towel material having an inner absorbent layer of cellulosic material and outer layers of microfibrous polyolefin material on opposite sides of the inner layer, the outer Iayers being spot fusion bonded through the inner layer to produce a towel having exceptionally high void volume for improved absorbency.

Description

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This invention relates to an absorbent hydrophilic and oleophilic multipurpose composite towel material and its method of manufacture.
Non-woven materials have long been used as disposable towels in a wide variety of applications. For example, such towels may be used as shop towels for wiping oil and grease from machine parts as well as for drying wet hands. They may also be used in the graphic arts trade for cleaning ink and solvents from printing elements. Another use is as hospital towels, which require high water absorbency and also alcohol absorbency. A further common use is as kitchen towels, which require oil and grease absorbency~ as well as high water absorbency.
The functional requirements of ~uch a towel are primarily rapid absorbency and the ability to hold and retain both aqueous liquids, such as water, and oleaginous liquids, such as oils, solvents and greases, even when gently squeezed; high abrasion resistance to provide a lint-free surface even after repeated usei and adequate wet and dry strength in order to maintain its integrity in use, so that, for example, it can repeatedly be pulled out of a pocket. In addition, it is highly desirable that such a towel have a soft, textile-like hand.
AccordinglyJ it is a major object of the present invention to pro-vide a novel absorbent hydrophilic and oleophilic multipurpose composite towel material having exceptionally high void volume for improved absorbency and one which also meets all of the above mentioned requirements.
The invention provides an absorbent hydrophilic and oleophilic multi-purpose composite towel material comprising: an inner hydrophilic absorbe~
layer of cellulosic material; and outer layers of microfibrous polyolefin material on opposite sides of said inner layer; said outer layers being spot usion bonded through said inner layer to produce a bonded composite material

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having low density and exceptionally high void volume for improved liquid absorbency.
It is a particularly important feature of the novel towel material of the invention that the bonding together o the outer layers occurs in the form of spot usion bonding through the inner layer. By so doing, utilizing the methods described, it is possible to eliminate a substantial proportion of the absorption-reducing bonded portions of heretofore known composite towels and so produce a towel material having both low density and exceptionally high void volume for greatly increased absorbency, both of aqueous and oleaginous liquids.
Advantages of the present invention will be apparent from the following detailed description of preferred embodiments of the invention, to-gether with the accompanying drawings, wherein:
Figure 1 is a perspective view, with portions broken away~ of the novel absorbent hydrophilic and oleophilic multipurpose composite towel material of the present invention;
Figure 2 is a sectional view taken along line 2-2 of Pigure l;
~igure 3 is a sectional view of a modification of the composite towel ma~erial of Figures 1 and 2; and Figure 4 is a schematic side view showing apparatus and methods of ; manufacture of the composite towel material of the invention.
Reerring to Figures 1 and 2S in general, the novel absorbent hydro-philic and oleophilic multipurpose composite towel material 10 of the invention has an inner absorbent layer 12 of cellulosic material and outer layers 14 and 16 of microibrous polyolefin material on opposite sides of inner layer 12, with the three layers being spot usion bonded together at discrete bonding areas 1~ through ilmer layer 12 to provide maximum void volume. The hydrophobic 2~' nature of the fibers of outer layers 14 and 16 provides acomposite towel mater-ial which tends to retain absorbed water within the absorbent inner layer 12 and so provide a dryer outer surface.
In Figure 3 is shown a modification of the absorbent hydrophilic and oleophilic multipurpose composite towel material of Figures 1 and 2, wherein a reinforcing layer 20 may be incorporated between two inner absorbent layers 12 and 13 and similarly bonded at areas 19 to provide a composite towel material 22 of increased strength.
Outer layers 14 and 16 are of synthetic amorphous microfibers, such as are described in United States Patent No. 3,978,185, of about 2 to 20 and, preferably, about 2 to 4 micron diameter and 2 to 4 inch length~ Commercial polypropylene me:Lt blown ibers, available from Riegel Products, Milford, N.J.
as #PP-0241 weighing 36 grams/square yard and ~PP-021599 weighing 12 grams/
square yard, have been found to be useful in the practice of the invention.
Such microfibers are hydrophobic and require the application of a minor proportion of non-irritating surfactant, such as Rohm and Haas Triton X-100 or Triton CR-5M, (Trademarks) so that they will be suitably wettable by water for use in the towel material of the present invention. Since they are oleophilic, they wet easily with oleaginous liquids, such as oils, greases and solvents.
They may be formed into a low density web of high bulk by conven-tional vacu~n web-forming processes and so may be deposited from a supply of bulk fibers to form outer layers 14 and 16 of composite towel material 10 or may be supplied in the roll form. However, since the web has little integrity, it is difficult to handle in roll form. Consequently, in order to provide such a web which may be easily handled in roll form, it may be desirable to treat the web with a suitable latex emulsion, which also enhances the abrasion :~L~Z~'7 resistance of outer layers 14 and 16, although such treatment may not be necessary under some circumstances. At the same time, the web may be treated with the necessary surfactant before winding it into roll form.
A suitable emulsion may include 20 percent relatively to the weight of dry microfiber web layer 14 and 16 of Rohm ~I Haas experimental acrylic 20 percent solids emulsion E-1285 for enhancing the abrasion resistance of the web, 0.5 percent of Rohm ~ Haas Triton GR-5M sulfo-succinate wetting agent for providing the necessary surfactant and 0.02 percent of Dow Corning H-10 silicon antifoam.
Inner absorbent layer 12 and 13 is preferably in the form of a mat of cellulose fibers, which is produced by disintegrating loosely held together bleached wood pulp, frequently referred to as "fluff", having a weight of about 60 grams/yard when laid down, ~or example. The "fluf" may contain about 5 to 30 percent, preferably about 13 percent, of a stabilizing thermoplastic powder which may thereafter be heated to about 180 degrees C to stabillze inner layer 12 and 13 in order to reduce its deterioration in use. As so stabilized, the cellulose fiber inner absorbent layer 12 ancl 13 may be supplied in roll form as "dry laid paper". Thus, inner absorbent layer 12 and 13 may be laid down - either directly rom a supply of "fluff" or~ alternatively, as "dry laid paper"
from a roll. Such "dry laid paper", having a weight of about 38 gramsjyard, is available as ~-45 manufactured by the Edet Company of Holland.
Alternatively, st,abilized soft wet-laid cellulose paper toweling material may be used.
For such stabilization, powders such as polyethylene with a low melting viscosity or a terpolymer of ethylene acrylic acid-acrylic acid ester, the latter being identified as TA 2957 of Plast Labor Co. of Bulle, Switzerland,may be used.

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If desired, "super-absorbent" materials~ such as PERMASORe 10 (Trademark) manufactured by National Starch may be incorporated into inner absorbent layer 12 and 13 to increase its water absorbency.
If used, reinforcing layer 20 may be any of a number of open9 light-weight, woven or non-woven, fabric materials, such as 7 gram/square yard HE-443 Maralay (Trademark) latex bonded open fabric manufactured by The Kendall Company or 8 gram/square yard polypropylene spun bonded Lutrafil (Trademark) fabric manufactured by the Lutravil Company.
Referring now to Figure 4, the layers of the composite material of Figure 3 of the invention may be assembled from two melt-blown fiber web rolls 116 and 114, two fluff suppliers 112 and 113 and a reinforcing material supplier 120 and deposited directly on conventional vacu~n web forming apparatus 100 to provide an assembled but unbonded composite web 11 which is then moved directly to a conventional thermal or ultrasonic spot fusion bonding apparatus 200 to provide composite bonded absorbent sheet material 22.
The bonding of the layers of composite web 11 by discrete thermal spot fusion bonding, preferably by bonding apparatus such as that disclosed in United States Patent Nos. 3,507,943 and 3,542,634 only in discrete bonded areas 18 or 19 which extend through inner layer 12 and 13 and reinforcing layer 20 and include both the thermoplastic material of inner layer 12 and 13 and the polyolefin material of outer layers 14 and 16, makes possible the provision of a novel absorbent hydrophilic and oleophilic multipurpose composite material of unusually low density and high void volume. Consistent with the requirements of material integrity, the total bonding area should be kept as low as possible to avoid unnecessary reduction in void volume~ about 5 to a maximum of about 25 percent being preferred, although up to about 40 percent may be found to be desirable in some circumstances.

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Under the high heat and pressure developed by bonding apparatus 200, the polyolefin microfibers of outer layers 14 and 16 in the bonded areas 18 and 19 lose their microfiber character and are usually melted into an opaque film including the thermoplastic powder of inner layer 12 and 13, if present, although a minor degree of aperturing may also occur. The cellulose material of inner layer 12 and 13 also develops a hydrogen bond, the so-called paper-makers bond, under these conditions.
Any desired pattern may be used to enhance the appearance of *he composite bonded material.
Other fusion spot bonding apparatus may also be used in the prac-tice of the invention, such as, for example, an ultrasonic embossing Pinsonic ~l'rademark) bonding apparatus manufactured by the J.M. ~lunter Machine Company.
In the event that the necessary surfactant treatment and any desired abrasion resistance treatment was not previously provided to the outer surfaces of outer layers 14 and 16 by earlier treatment, such may be accom-plished by spraying onto the opposite surfaces of composite bonded material 22 a suitable surfactant and latex emulsion, such as that described above, by spray apparatus 220 and 221. Thereafter, composite material 22 may be heated by heaters 230 and 231 to dry the surfactant and to set the latex emulsion on the outer surfaces of outer layers 14 and 16.
In the event that the powder bonding material of inner layer 12 and 13, if used, was not previously heated to bond such layers, heaters 230 and 231 also serve to melt any remaining powder bonding material and so further bond inner layer 12 and 13.
The finished absorbent hydrophilic and oleophilic multipurpose composite towel material 22 of the invention may then be rolled up by conven-tional rollers 300 into a roll 24.

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It will be apparent to those skilled in the art that various modi-fications, within the spirit of the invention and the scope of the appended claims, will be apparent to those skilled in the art.

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. An absorbent hydrophilic and oleophilic multipurpose composite towel material comprising:
an inner hydrophilic absorbent layer of cellulosic material; and, outer layers of microfibrous polyolefin material on opposite sides of said inner layer;
said outer layers being spot fusion bonded through said inner layer to produce a bonded composite material having low density and exceptionally high void volume for improved liquid absorbency.

2. The composite material of claim 1, further including a reinforcing layer adjacent said inner layer.

3. The composite material of claim 1 or 2, wherein said spot bonding covers between about 6 - 40% of the total surface area of said composite material.

4. The composite material of claim 1 wherein the outer layers has outer surfaces having an abrasion resistant coating thereon.

5. The composite material of claim 1 wherein said cellulosic material contains between about 5 to 30 percent of thermoplastic bonding powder therein.

6. An absorbent hydrophilic and oleophilic multipurpose composite towel material comprising:
an inner hydrophilic absorbent layer of cellulosic material containing between about 5 to 30 percent of thermoplastic bonding powder therein a reinforcing layer of lightweight fabric material adjacent said inner layer outer layers of microfibrous polyolefin material com-posed of melt-blown microfibers having diameters in the range of about 2 to about 200 microns on opposite sides of said inner layer and said reinforcing layer, said outer layers having outer surfaces having an abrasion resistant and surfactant coating thereon said inner and outer layers being spot fusion bonded through said inner layer and said reinforcing layer throughout between about 6-40% of the total surface area of said composite material to produce a bonded composite material having low density and exceptionally high void volume for improved liquid absorbency.

7. The composite material of claim 1 or 6, wherein said microfibrous polyolefin material is composed of melt-blown micro-fibers having diameters in the range of about 8 to about 400 microns.