EP0059613A1

EP0059613A1 - Method of packaging a compressible textile product

Info

Publication number: EP0059613A1
Application number: EP82300978A
Authority: EP
Inventors: Alan H. Miller; Jens Moe (Nmi)
Original assignee: Cellu Products Co Inc
Current assignee: Cellu Products Co Inc
Priority date: 1981-02-26
Filing date: 1982-02-25
Publication date: 1982-09-08
Also published as: CA1199569A; KR830009984A

Abstract

A method and apparatus is provided for the packaging of a compressible textile product (12) under a high degree of compaction to facilitate handling, shipment and storage. Also, the product in the resulting package (50) is essentially "bone" dry, which serves to prevent the formation of destructive permanent wrinkles, or fiber compression set, in the product. The moisture is removed in accordance with the present invention by applying microwave energy to the product at an energy level and for a time sufficient to vaporize substantially all of the ambient moisture therein, and the product is thereafter enclosed in a vapor impermeable plastic bag (37). The resulting package is then compressed and sealingly closed, to thereby maintain the compreseed condition of the product and prevent moisture regain in the product.

Description

The present invention relates to a method and apparatus for compacting and packaging bulky textile products to substantially reduce their bulk and thereby facilitate shipment and storage, and to the resulting package.
Prior attempts to compact bulky textile products, such as compressible consumer textile products and bulk fiber packages, to facilitate their shipment and storage, have not met with full commercial acceptance since many such products develop semi-permanent or even permanent wrinkles or creases or a permanent fiber compression set, after a period of time in a compacted condition. Such wrinkles, creases, or compression set of the fibers can render the product unsuitable for consumer sale or other intended use. To alleviate this problem, it has been proposed to initially reduce the moisture content in consumer textile products, and then enclose them in moisture impermeable packages which may thereafter be evacuated to reduce their bulk. More particularly, in the prior U. S. patents to Shishoo, Nos. 3,961,458 and 4,199,916, it is proposed that the moisture content be reduced by exposing the textile material to a conditioning environment having a low relative humidity for an extended period of time, and thereafter vacuum packaging the material. In the '916 patent, it is suggested that the conditioning may be conducted by passing the textile material through an elongate tunnel, which includes an initial treatment zone wherein the conditioning air is maintained at 20-30 ¼ C and 15-30% relative humidity, and a subsequent stabilization zone wherein the conditioning air is maintained at 15-201/4 C and 5-12% relative humidity. The treatment time in the tunnel is necessarily long in order to permit the moisture level in the textile fabric to reach an equilibrium with the relative humidity of the conditioning air, and it is indicated in the patent that up to 240 minutes may be required.
As will be apparent, the processes disclosed in the two above Shishoo patents are not totally satisfactory from a,commercial point of view, since an extended treatment time is required, which substantially limits the production capacity. Further, substantial energy, space, and equipment are required to control the temperature of the conditioning air, as well as to lower the relative humidity of such air to the required low levels. Still further, the textile products must be treated in an open unfolded condition, and it is not realistically possible to obtain very low moisture levels in the textile products, such as below 10% of its normal content, since an exorbitant con- - ditioning time in air of extremely low relative humidity would be required.
It is accordingly an object of the present invention to provide a commercially viable method and apparatus for packaging textile products under compacted conditions to thereby reduce their bulk and thus facilitate handling, shipment and storage.
It is a more particular object of the present invention to provide a method and apparatus for packaging textile products under compacted conditions, and wherein the textile product is characterized by the substantial absence of permanent wrinkles, creases or fiber compression set upon opening of the package.
It is also an object of the present invention to provide a method and apparatus of the described type, and wherein substantially all of the moisture in the textile product may be removed to thereby maximize the beneficial results achieved by the absence of moisture, and while requiring only a short time and utilizing relatively low levels of energy and limited processing space.
It is still another object of the present invention to provide a package of a compressible textile product, and wherein the material is compressed to. at least about 50% of its natural volume, and has a moisture content of not more than about 10% of its normal content.
. These and other objects and advantages of the present invention are achieved in the embodiment illustrated herein by the provision of a method and apparatus which includes the steps of drying the textile product by applying microwave energy thereto at an energy level and for a time sufficient to vaporize at least a substantial portion, and preferably substantially all, of the ambient moisture therein, and then promptly compressing the textile product and packaging the compressed product in an essentially vapor impermeable enclosure which maintains the compressed condition thereof. Preferably, heated ambient air is passed across the surface of the textile product during the drying step, to facilitate the removal of the vaporized moisture from the textile product and thereby speed the drying process.
The use of microwave energy to vaporize the moisture in the textile material in accordance with the present invention has been found to result in several surprising and significant advantages. Specifically, the microwave energy has been found to rapidly heat and vaporize the moisture in the textile material, and results in a significant shortening of the treatment time to usually between about 2 to 3 minutes. In addition, the microwave energy effectively drives the vaporized moisture out of the interior of the textile material and so that the moisture may be readily removed from the exterior surface of the material by an airstream of heated ambient air passing thereacross. Thus there is no need for ventilating air to penetrate to the interior of the product to carry off the moisture. This is a significant advantage, since it minimizes the volume of the ventilating air and it permits many textile products to be treated in folded condition. Thus the products may be initially folded into consumer sized packages prior to their treatment, and the treated packages are in a form which may be immediately packaged without further manipulation, which could result in an undesirable moisture regain. The use of microwave energy is also believed to result in a reduction in energy consumption as compared to conventional heating methods, and it is able to rapidly and uniformly remove substantially all of the moisture throughout the interior of the textile material, without risk of overheating and damage to the textile material. Also, the equipment associated with the use of microwave energy requires a minimum of space and is relatively inexpensive.
Some of the objects and advantages of the invention having been stated, others will appear as the description proceeds, when taken in connection with the accompanying drawings, in which-Figure 1 is a schematic flow diagram illustrating the various steps of a method representing one embodiment of the present invention;

Figure 2 is a partly schematic perspective view of a microwave housing adapted for use with the present invention;
Figure 3 is a sectional end view of the microwave housing taken substantially along the Line 3-3 of Figure 2;
Figure 4 is a partly schematic perspective view of the apparatus for inserting the textile products into an opened bag in accordance with the present invention;
Figure 5 is a side elevation view of a por- . tion of the apparatus shown in Figure 4;
Figure 6 is a schematic perspective view of an apparatus for compressing the textile product and for heat sealing the open end of the enclosing bag;
Figure 7 is a view similar to Figure 6 and showing the apparatus in its closed or compressed condition;
Figure 8 is a sectional view of a textile product adapted to be processed in accordance with the present invention, namely, a pillow, and taken substantially along the Line 8-8 of Figure 4;
Figure 9 is a sectional view of the product shown in Figure 8, after having been compressed and packaged in accordance with the present invention; and
Figure 10 is a perspective view of the product shown in Figure 9.

Referring more specifically to the drawings, Figure 1 schematically illustrates the basic components and steps of one embodiment of the present invention. In this regard, the present invention is illustrated as packaging pillows, but it will be understood that the present invention is equally applicable for packaging any of a variety of other compressible textile products. As used herein, the term "compressible textile product" includes consumer products such as bedspreads, quilts, towels, or garments, as well as bulk fiber packages and non-woven fiber webs or materials, and which may be composed of either natural or synthetic fibers. In the case of relatively large textile products, it is preferred that they be folded into a consumer sized configuration prior to treating and packaging as hereinafter further described.
In accordance with the illustrated embodiment of the invention, the textile products or pillows 12 to be packaged are serially advanced through an elongated housing or tunnel 14 wherein they are dried by applying microwave energy thereto. The tunnel 14 is typically about 45 feet in length, and it includes an endless perforated conveyor 16 having an upper run 17 extending horizontally through the tunnel for supporting the products 12 thereon. The tunnel 14 includes an entering end portion 20 and an exiting end portion 21, each of which have a relatively short height, on the order of about 4 inches, which are designed to prevent leakage of microwave power from the tunnel.
The tunnel further includes a warm air duct system 22, wherein ambient outside air, which is preferably initially heated by electric heaters or the like to about 43 - 60°C., is passed laterally through the tunnel and across the surface of the products. In this regard, the air duct system typically has a capacity of about 10,000 cfm, and the air enters the side of the tunnel so as to pass upwardly through the upper run 17 of the belt and then exhaust laterally from the tunnel, note Figure 3. The moving heated airstream acts to carry away the vaporized moisture from the products, and thus serves to speed the drying time, while also helping to maintain a relatively low temperature in the interior of the products. Also, it will be noted that with the present invention, the vapor content of the air is preferably not reduced prior to being circulated through the tunnel, and thus the air will contain substantially all of its ambient moisture vapor. If desired, all of the air may be recirculated so as to minimize heat loss, although it may be necessary to introduce a sufficient amount of outside ambient air to limit the build up of moisture vapor in the circulating air.
A second endless perforated conveyor 24 is positioned with its lower run 25 extending through the tunnel and disposed in spaced relation above the upper run 17 of the lower conveyor, so as to supportingly contact the textile products 12 during passage through each of the entering end portion 20 and the exiting end portion 21. Thus the upper conveyor 24 serves to compress any bulky products to permit them to pass through the narrow entering and exiting end portions.
The power unit for generating the microwave energy in the tunnel 14 is generally conventional, and may for example comprise the system manufactured by Microdry Corporation of San Ramon, California, as Model IV-30-S. The power unit is typically designed to generate up to 30 KW of microwave power at 915 MHz, a frequency allotted by the FCC to commercial heating equipment. Also, the design of the entering end portion.20 and exiting end portion 21 for preventing leakage of microwave power is conventional, note for example the U. S. Patent to Smith, No. 3,858,022.
The speed of the conveyors 16 and 24, and the level of microwave energy, are each determined so that the moisture content of the textile products is preferably reduced to less than about 10% of its normal content, and most preferably is reduced almost to zero so that the product is essentially "bone" dry. In the described apparatus, the products 12 remain in the tunnel 14 for a period of about 2 to 3 minutes in order to accomplish this reduction in moisture content. Also, the microwave energy acts to raise the temperature of the textile material itself only a limited amount, and which is insufficient to cause damage to the product. Typically, the temperature of the material will be raised to between about 60 - 66°C , it being understood that the amount of the temperature increase will also depend upon the initial moisture content of the material.
Upon exiting from the microwave tunnel 14, the dried products 12 are directed immediately to a bagging unit 30 as best seen in Figures 4 and 5. The unit includes a feed device having upper and lower cooperating conveyors 32, 33 and an automatic bagging device which includes a stack 36 of suitable plastic bags 37, an air jet 38 for sequentially opening the top bag as a product is delivered, and a cyclically operated lever arm 40 for advancing the product and enclosing bag to a discharge conveyor 42. If desired, the conveyors 32, 33 may be positioned so as to compress each product as it enters the associated bag, so that smaller and thus less costly bags may be employed.
From the bagging unit 30, the products 12 and enclosing bags 37 are advanced to a compressing and sealing unit 44, wherein a flat plate 46 is lowered onto each product by a suitable pneumatic piston ram 47 or the like. The force of the ram acts to substantially compress the product, preferably to at least 50% of its original volume, and up to about 20-30% of its original volume in the case of more compressible products such as the illustrated pillows. A partial vacuum may also be drawn in the bag to facilitate the compressing of the product, and to remove the remaining air. A heat sealing bar 48 is mounted on the front edge of the plate 46, and is automatically lowered by the piston 49 while the product is under compression to heat seal the open end of the plastic bag, note Figure 7.
As will be apparent, the resulting compressed product 50 is maintained in its compressed condition by the bag 37. Also, the material of the bag is selected so as to have a very low moisture vapor permeability, which effectively prevents the return of moisture into the interior of the product for a substantial period of time. As one example, polyethylene sheeting is commercially available in a number of grades having differing moisture vapor transmission rates. Since those materials having the lowest transmission rate are the more expensive, it is contemplated that the textile products may be initially individually packaged in a less expensive material of relatively high permeability, and then a number of such packages would be repackaged in a material of very low vapor permeability. It is further contemplated that the resulting bulk packages could be prepared for shipment by placing one or a plurality of the bulk packages between top and bottom sheets of corrugated paper, and then interconnecting the sheets with suitable strapping, to thereby minimize the amount of outer corrugated paper employed.
When the packages 50 are opened at the retail outlet or by the consumer, the product 12 should be exposed to ambient air for a period of time to permit it to expand and recover its normal moisture content and original shape and bulk. While some wrinkles will normally be present immediately upon opening of the package, these wrinkles are not permanent and they will usually disappear upon full moisture regain without the need for pressing or other treatment. In this regard, such recovery ambient air should have a relative humidity of at least about 50 to 60%, and preferably higher, since the higher the relative humidity, the more rapid the full moisture regain and recovery of the original shape and bulk.
In the drawings and specification, there has been set forth a preferred embodiment of the invention, and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. A method of packaging a compressible textile product (12) so as to reduce its bulk and thereby facilitate subsequent handling, shipment or storage, and with the substantial absence of permanent wrinkles being formed in the product or fiber compression set, said method being characterised by the steps of removing at least a substantial portion of the ambient moisture from the product and including applying microwave energy to the product to vaporize the moisture therein, then promptly compressing the textile product, and packaging the compressed textile product in an essentially vapor impermeable enclosure (37) and so as to maintain the compressed condition thereof and substantially preclude moisture regain in the textile product.

2. The method as claimed in claim 1, characterised in that the moisture removing step acts to reduce the moisture content of the textile product to less than about 10% of its normal content..

3. The method as claimed in claim 1 or 2, characterised in that the compressing step acts to reduce the bulk of the product to at least about 50% of its original size.

4. The method as claimed in claim 3, characterised in that the moisture removing step acts to raise the temperature of the textile product to between about 60 to 66°C.

5. The method as claimed in any one of claims 1 - 4, characterised in that the moisture removing step further includes passing an airstream across the surface of the textile product to carry away the vaporized moisture from the textile product.

6. The method as claimed in claim 5, characterised in that the airstream constitutes heated air which contains substantially all of its ambient moisture vapor.

7. The method as claimed in any one of the preceding claims, characterised by the steps of serially advancing a plurality of the products (12) through a housing (14), while applying microwave energy to the products at an energy level sufficient to vaporize at least a substantial portion of the ambient moisture in each product during its passage through the housing, and while passing an airstream across the advancing textile products in the housing to carry away the vaporized moisture which is released from the products, compressing the products promptly upon leaving the housing, and then packaging each of the compressed products (12) in an essentially vapor impermeable enclosure (37) so as to maintain the compressed condition thereof and substantially preclude moisture regain in the textile product.

8. The method as claimed in claim 7, characterised in that the compressing and packaging steps include inserting each of the products (12) into an open bag (37) formed of an essentially vapor impermeable flexible plastic sheet - material upon leaving the housing, then compressing each of the procuts to substantially reduce its bulk while it is within the bag, and then sealing the open end of the bag so as to maintain the compressed condition of the resulting package.

9. An apparatus for packaging compressible textile products (12) so as to reduce the bulk thereof and facilitate subsequent handling, shipment or storage, and with the substantial absence of permanent wrinkles being formed therein or fiber compression set, characterised in that it comprises means (16) for conveying individual textile products in succession along a path of travel, means (14) disposed along said path of travel for applying microwave energy to the textile products soas to vaporize at least a substantial portion of the ambient moisture therein, and means (30, 44) disposed immediately adjacent the downstream end of said path of travel for serially compressing and sealingly packaging the textile products in a substantially vapor impermeable material (37), and such that the packaging material maintains the compressed condition of the products and substantially precludes moisture regain in the textile products.

10. The apparatus as claimed in claim 9, characterised in that it further comprises means (22) for passing an airstream across the textile products while the microwave energy is being applied thereto, and such that the airstream acts to carry away the vaporized moisture which is released from the products.

11. The apparatus as claimed in claim 10, characterised in that said means for applying microwave energy to the textile products comprises an elongate housing (14), and means disposed within said housing for generating microwave energy, and said conveying means comprises an endless conveyor (16) having an upper run (17) extending through said housing for supporting the textile products thereon.

12. The apparatus as claimed in claim 11, characterised in that said housing (14) further comprises an entering end portion (20) and an exiting end portion (21), and means at each of said entering end portion and exiting end portion for suppressing the emission of microwave energy therefrom.

13. The apparatus as claimed in claim 12, characterised in that said conveying means further comprises a second endless conveyor (24) having a lower run (25) extending through said housing and disposed in spaced relation above the upper run (17) of said first mentioned endless conveyor (16) to supportingly contact the textile products during passage through each of said entering end portion (20) and said exiting end portion (21).

14. The apparatus as claimed in any one of the preceding claims 9 to 13, characterised in that said compressing and packaging means comprises means (36, 38) for sequentially feeding an opened bag to an assembly station, and means (32, 33) for sequentially delivering individual products into each opened bag at said assembly station.

15. The apparatus as claimed in claim 14, characterised in that said compressing and packaging means further comprises compactor means (46) positioned adjacent said assembly station for sequentially compacting each product and its enclosing bag.

16. The apparatus as claimed in claim 15, characterised in that said compressing and packaging means further comprises heating means (48) for heat sealing the open end of the . enclosing bag while each product and its enclosing bag are compacted by said compactor means.

17. A package (50) of a compressible textile product having a reduced bulk to facilitate handling, shipment and storage, and with the substantial absence of permanent wrinkles being formed therein upon the opening of the package or fiber compression set, characterised in that it comprises a compressible textile product (12) compressed to at least about 50% of its natural volume and having a moisture content of not more than about 10% lf its normal content, and a flexible plastic sheet material (37) of relatively low moisture vapor permeability sealably enclosing said textile product to maintain its compressed condition and substantially preclude additional outside moisture vapor from reaching the textile product.

18. The package as claimed in claim 17, characterised in that the textile product comprises a finished textile product adapted for sale to the consumer.

19. The package as claimed in claim 17 or 18, characterised in that the textile product is compressed to at least 30% of its natural volume.