Compress and method of manufacture of a compress

Abstract: A reusable and microwavable hot insulated compress has a bottom laminate (15,16,17), a first pocket containing a gel (18), a middle laminate (19,20,21) being positioned above the first pocket and including a top layer (17) of insulative material, a second pocket (18) being provided with a dead air space as additional insulation above the insulative material, and a top laminate (19,20,21) being positioned above the second pocket. The bottom, middle and top laminates each have outer peripheral edges that are bonded together by a radio frequency (RF) heat-sealing step. A method is also disclosed for manufacturing the compress.

Description: The present invention relates to a therapeutic compress and, in particular, to a reusable and microwavable hot insulated compress. The invention also relates to a method for manufacturing such a compress. Heat therapy is a recommended treatment for relieving minor pain caused by muscle aches, soreness, stiffness, cramps, and arthritis. The therapy works by providing heat through the skin to the affected muscles to dilate the blood vessels therein and, thus, to increase the circulation of the blood therethrough. For many years, this heat therapy has been provided via a hot compress which was held against the affected portion of the body. Subsequently, manufacturers developed compresses that could serve to provide either hot or cold therapy. Cold therapy is a recommended treatment for relieving minor pain caused by injuries to muscles which swell in response to such injuries. This cold therapy works by withdrawing heat through the skin from the injured muscles to constrict the blood vessels therein and, thus, to reduce swelling by decreasing the circulation of the blood through such injured muscles. Such a cold therapy pack is shown in U.S. Patent No. 4,243,041 which issued to Malcolm D. Paul on January 6, 1981. Examples of compresses that serve to provide either hot or cold therapy are the prior art packs shown in the following references: More recently, some compresses have been made microwavable so that they may be available more quickly than conventional compresses which need to be either boiled or frozen before they are ready for use. Such microwavable compresses are shown in the following U.S. Patents: U.S. Patent No. Inventor(s) Issue Date 4,488,552 McCann et al. Dec. 18, 1984 4,671,267 Stout June 09, 1987 4,756,311 Francis, Jr. July 12, 1988 However, such prior art compresses, either hot or cold or dual in nature, are usually made with thin plastic, such as polyethylene, which is clammy to touch and has an uncomfortable feeling for the user. Also, because their outer walls are usually very thin, such prior art compresses are often too hot to handle after they are first heated. Consequently, the user is required to hold such a hot compress against the sore muscle area with either a towel, or a paper cloth, or the like. Holding the hot compress in this manner is cumbersome and often results in slippage of the hot compress away from the muscle area. Occasionally, such slippage will result in a fall that will rupture the outer walls of the compress, thus spilling the fluid contents thereof. Accordingly, there is a distinct disadvantage in using current state of the art hot compresses. In US-A-2562121 (Poux) there is disclosed a therapeutical device for heating parts of the human body or for drawing heat therefrom. The device consists of a plurality of permanently sealed liquid-containing compartments or cells having air-containing compartments or cells arranged therewith which are adapted to act as a cushioning and/or insulating means for the liquid-containing compartments or cells. The device comprises an elongate body member made of flexible material such as rubber or plastics material. On one side of the body member there is provided a plurality of compartments or cells with each being permanently sealed and containing a suitable liquid, preferably water. On the opposite side of the body member there is provided a plurality of permanently sealed compartments or cells with each containing a suitable amount of air. It is the purpose of the air compartments to provide a cushion between the patient and the liquid-containing compartments so as not to be uncomfortable to the patient especially if the liquid therein is frozen solid. Also, these air compartments provide an insulating effect in case it is desired not to withdraw too rapidly too much heat from the body so as to prevent the patient from becoming subject to a chill. In US-A-4756311 (Francis) there is disclosed a thermal compress capable of being heated quickly by microwave energy without adversely affecting the components of the compress. The device comprises a plastic envelope sealed for example by heat sealing dielectric treating. The envelope is fabricated from a stretchable laminate of a pair of films which may comprise an inner film of polyethylene and an outer layer of nylon. The envelope contains a liquid or paste or gel. Only a single pocket containing the gee is provided in the compress. According to the present invention in one aspect, there is provided a compress comprising: a bottom wall means; a middle wall means positioned above the bottom wall means; a first pocket means formed between the bottom wall means and the middle wall means; a top wall means positioned above the middle wall means; and a second pocket means formed between the middle wall means and the upper wall means for providing a dead air space; characterised in that each wall means is a laminate; the middle wall means includes a top layer of insulative material, with the second pocket means providing the dead air space as additional insulation above the middle wall means; and the first pocket means contains a gel above the bottom wall means. In US-A-3940905 (Perry) there is disclosed a method of making a thermal compress comprising sandwiching a wall between two sheets and connecting the sheets to the wall along a closed line to form separate compartments which are charged with a respective thermally reactive substance. The method further comprises leaving an opening into each said compartment through the aforementioned line, then charging the compartment with respective of said substances through the openings and then closing each said opening. The device includes a tear strip which in use is tensioned to produce an opening between the two compartments to provide for a mixing of the thermally reactive substances in the two compartments. In one construction, the device includes a further sheet forming an additional compartment which is filled with air to provide for ameliorating the heating or cooling effect as applied to the skin of the person using the device or being treated with the same. In accordance with the present invention in another aspect, there is provided a method of manufacturing a compress, comprising the steps of: providing a bottom wall; positioning a middle wall means above the bottom wall means; providing a first pocket formed between the bottom wall means and the middle wall means; positioning a top wall means above the middle wall means; providing a second pocket formed between the middle wall means and the top wall means with dead air space; characterised by: providing each of the wall means as a laminate; including in the middle wall means a top layer of insulative material, with the second pocket means providing the dead air space as additional insulation above the middle wall means; and containing a gel in the first pocket above the bottom wall means. In accordance with a preferred form of the apparatus aspect of the invention, the bottom wall means comprises: a first layer of fabric having a top surface; a first layer of adhesive spread on the top surface of the first layer of fabric; and a first layer of plastic adhered to the top surface of the first layer of fabric by the first layer of adhesive; the middle wall means comprises: a second layer of plastic being positioned above the pocket containing the gel, said second layer of plastic having a top surface; a second layer of adhesive spread on the top surface of the second layer of plastic; a layer of insulative material adhered to the top surface of the second layer of plastic by the second layer of adhesive; and the top wall means comprises: a third layer of plastic positioned above the pocket means for providing the dead air space as additional insulation, said third layer of plastic having a top surface; a third layer of adhesive spread on the top surface of the third layer of plastic; and a second layer of fabric adhered to the top surface of the third layer of plastic by the third layer of adhesive. In accordance with the method aspect of the invention, it is preferred that the method includes, providing the bottom wall means by providing a first layer of fabric having a top surface; spreading a first layer of adhesive on the top surface of the first layer of fabric; and adhering a first layer of plastic to the top surface of the first layer of fabric by the first layer of adhesive; providing the middle wall means by positioning a second layer of plastic above the first pocket, said second layer of plastic having a top surface; spreading a second layer of adhesive on to the top surface of the second layer of plastic; and adhering a layer of insulative material to the top surface of the second layer of plastic by the second layer of adhesive; and providing the top wall means by positioning a third layer of plastic above the pocket means provided with dead air space as additional insulation, said third layer of plastic having a top surface; spreading a third layer of adhesive on to the top surface of the third layer of plastic; and adhering a second layer of fabric to the top surface of the third layer of plastic by the third layer of adhesive. It is a primary object of the present invention to provide a reusable and microwavable hot compress which has an intermediate insulative layer that allows a user to handle the compress easily when such a compress is hot and ready to be applied to a sore muscle area. It is another object of the present invention to provide a method of manufacturing such a compress with an intermediate insulative layer and a dead air space on one side of a gel-filled space so that the user's hand is not burned between applications when holding the heated compress against the sore muscle area. These and other objects and advantages of the present invention will become readily apparent from a study of the following brief description of the drawings and the subsequent detailed description of the preferred embodiment. Fig. 1 is a perspective view of the compress of the present invention. Fig. 2 is a short side elevational view of the compress of the present invention. Fig. 3 is a top plan view of the compress of the present invention. Fig. 4 is a partially broken away and enlarged cross-sectional view of the short side of the compress shown in Fig. 2. Fig. 5 is a pictorial view illustrating one method of using the compress of the present invention. In Fig . 1 of the drawings, there is shown a perspective view of a compress 10 of the present invention. In Fig. 2, an elevational view of a short side of the compress 10 is shown. A first bottom layer 11 of polyester fabric is 0.20 to 0.25 mm (eight to ten mils) thick and a second top layer 21 of polyester fabric is also 0.20 to 0.25 mm (eight to ten mils) thick. In Fig. 3, a top plan view of the compress 10 is shown with only the second top layer 21 of polyester fabric being visible. A bottom plan view showing only the first bottom layer 11 of polyester fabric would be identical to this top plan view of the compress 10. In Fig. 4, the short side of the compress 10 shown in Fig. 2 is partially broken away and enlarged to illustrate the various layers of the invention in cross-section. The view of the layers in Fig. 4 will be discussed from bottom to top with the bottom layer intended to be applied next to the affected body part. In Fig. 4, the first bottom layer 11 is made of polyester fabric, as indicated previously in the discussion of Fig. 2. Next, there is a first bottom layer 12 of plastisol adhesive that is spread very thinly on a top surface of the layer 11 of polyester fabric. Then, a first bottom layer 13 of vinyl plastic 0.25 to 0.30 mm (10 to 12 mils) thick is laid on top of the layer 12 of the plastisol adhesive so that the layer 13 of vinyl plastic adheres to the layer 11 of polyester fabric. A gel 14 is later placed into a first pocket provided above the layer 13 inside the compress 10. The first pocket is formed by a top surface of the first layer 13 of vinyl plastic and by a bottom surface of a second layer 15 of vinyl plastic. Both freezable and heatable gels are known in the prior art. The heatable gel 14 used in the preferred embodiment of the present invention includes about 73 to 77 percent distilled water by weight, about 22 to 24 percent boiling point elevator by weight, and about one to five percent thickening agent by weight. The preferred boiling point elevator is propylene glycol which is often used in cosmetics and foods. The preferred thickening agent is an acrylic acid polymer powder, such as Carbopol 940 (Trademark) manufactured by B.F. Goodrich Co. Other ingredients to suppress bacterial growth within the gel 14 and to enhance either processibility or shelf life may be added in amounts varying from one to four percent by weight, depending upon the combination of distilled water, boiling point elevator, and thickening agent. The second middle layer 15 of vinyl plastic is provided with its bottom surface immediately above the pocket containing the gel and is adjacent to the gel 14 in the compress 10. A second middle layer 16 of plastisol adhesive is spread very thinly on a top surface of the layer 15 of vinyl plastic. Next, a sole layer 17 of open-celled insulative polyester foam is placed on top of the layer 16 of plastisol adhesive so that the layer 17 of insulative foam adheres to the layer 15 of vinyl plastic. Next, a dead air space 18 is provided in a second pocket as an additional insulation above the layer 17 of insulative foam in the compress 10. The second pocket is formed by a top surface of the layer 17 of insulative foam and by a bottom surface of a third layer 19 of vinyl plastic. The third top layer 19 of vinyl plastic is provided with its bottom surface immediately above and adjacent to the dead air space 18. A third top layer 20 of plastisol adhesive is spread very thinly onto a top surface of the layer 19 of vinyl plastic. Finally, the second top layer 21 of polyester fabric is placed on the layer 20 of plastisol adhesive so that the layer 21 of polyester fabric adheres to the layer 19 of vinyl plastic. As indicated previously in the discussion of Fig. 2, the layer 21 is 0.20 to 0.25 mm (eight to ten mils) thick. In the process for manufacturing the compress 10, as can be readily seen from the right-hand side of Fig. 4, the first layer 11 of polyester fabric is either bonded or laminated together with the first layer 13 of vinyl plastic by the first layer 14 of plastisol adhesive to form a bottom laminate 22. Likewise, the second layer 15 of vinyl plastic is either bonded or laminated together with the sole layer 17 of insulative foam by the second layer 16 of plastisol adhesive to form a middle laminate 23. Similarly, the third layer 19 of vinyl plastic is either bonded or laminated together with the second layer 21 of polyester fabric by the third layer 20 of plastisol adhesive to form a top laminate 24. In the next step of the process for manufacturing the compress 10, the bottom laminate 22, the middle laminate 23, and the top laminate 24 are cut to size and heat-sealed together to form a coplanar outer edge 25, best seen on the left-hand side of Fig. 4, for the compress 10. The heat sealing of the three laminates 22, 23 and 24 together to form the outer edge 25 is accomplished by radio-frequency (hereinafter RF) heating which essentially heats the internal molecular structure of the various plastic layers at 27.12 megahertz to cause an outer portion of each plastic layer to melt into the interstices of the fabric and foam layers without scorching the outer surfaces of such fabric and foam layers. In the known prior art methods, various heat-sealing processes are known to scorch occasionally any fabric layers. The avoidance of scorching is an important advantage of the manufacturing process of the present invention over known prior art methods. In other words, the outer edge 25 of the compress is formed by the RF heat-sealing of all coextensive plastic layers 13, 15 and 19 so that they melt into the bottom fabric layer 11, the insulative foam layer 17, and the top fabric layer 21, respectively. This heat-sealing step is carried out around substantially the entire periphery of the outer edge 25 except for two openings 26 and 27 which are left at one end of the compress 10. These two openings 26 and 27 form entrances into the first and second pockets, respectively, and are seen on the right-hand side of Fig. 4. Through opening 26, the gel 14 is squirted into the first pocket in the compress 10. Through opening 27, air is pumped into the second pocket that provides the dead space 18 inside the compress 10. The squirting of the gel 14 into the first pocket and the pumping of the air into the space 18 are steps that may be carried out either separately or simultaneously during the manufacturing process. The final step of the method of the present invention involves RF heat-sealing of the openings 26 and 27 so that the gel 14 and the dead air in the space 18 are sealed inside the compress 10. As a result of the last two manufacturing steps of creating the dead air space 18 and closing the opening 27 with RF heat, the compress 10 is provided with a distinct advantage over the prior art when considered in conjunction with the earlier manufacturing step of laminating the layer 17 of insulative foam into the middle laminate 23 inside the compress 10. This advantage is that the top layer 21 is cooler than the gel 14, even after microwaving. This advantage is best realized when viewing Fig. 5 in which the compress 10 is held by a user's hand H on the topmost layer 21 so that heat is radiated into an affected part of the user's body, e.g. in this case an injured knee K of the user's leg L, without the need for any towels, paper cloths, and the like, which are likely to allow slippage of the compress 10 onto the ground or floor. Before use of the present invention, as shown in Fig. 5, a person will be able to tell the coolest top layer 21 from the bottom layer 11, seen only in Figs. 2 and 4, because the manufacturer will have either clearly marked the coolest top layer 21 to be held by the user's hand H or color-coded the same coolest top layer 21 so that the layer 21 can be easily distinguished from the hot bottom layer 11. For example, such color coding may involve the use of red ink or dye to indicate the hot bottom layer 11 and the use of blue ink or dye to indicate the coolest top layer 21. There are several other features that make the present invention more advantageous than known prior art devices. First, the compress 10 made by the above-described manufacturing method uses layered plastic and fabric materials that are designed to be expandable to allow for the escape of steam through the layers 11, 12 and 13 during the microwave heating of the compress 10. In other words, the layers 11-13 are permeable to water vapor because the microscopic interstices function as pinholes to allow the release of steam from the heated gel 14, thus acting as a safety feature in the event that the user inadvertently overheats the compress 10 either in the microwave oven or during heating in a conventional oven. For example, the prior art compress which is the subject of U.S. Patent No. 4,756,311 to Francis, Jr., is specifically claimed as a gel pack that does "not pass steam produced during heating ... by microwave energy". Experiments have shown and it is tacitly admitted by the inventor that this particular prior art compress is unfortunately likely to explode if heated in a microwave oven for more than four minutes. A second advantageous feature of the present invention is that the layer 17 of insulative foam and the dead air space 18 together function to prevent heat loss from the microwaved hot gel 14. Furthermore, they jointly serve to reflect the heat radiating from the hot gel 14 into the affected portion of the user's body, such as the knee K shown in Fig. 5. A third advantageous feature of the present invention is that, because the layer 17 of insulative foam is inside the compress 10 and is adjacent to the dead air space 18, the heat emanating from the microwaved hot gel 14 in a direction lateral to the affected portion of the user's body is reduced much more substantially than known prior art compresses having either an outer insulative layer or a single inner insulative layer . Such known prior art compresses with significant lateral emanation of heat are shown in the following references: U. S. Patent No. 3,874,504 of Verakas; U.S. Patent No. 3,893,834 of Armstrong; U.S. Patent No. 4,596,250 of Beisang, III et al.; and U.K. Patent No. 1,383,536 of Turner. A fourth advantageous feature of the present invention is that, because the outermost layer 21 is made of polyester fabric, this layer 21 can be easily printed upon in a decorative manner and feels very comfortable to the user's hand H seen in Fig. 5. Known prior art compresses, whether hot or cold, are usually made with outer layers of thin polyethylene plastic that is difficult to print upon and is clammy to touch, thus giving an uncomfortable feeling to the user's hand. A fifth advantageous feature of the present invention is that, because the outermost layer 21 is made of 70-denier interlocked or nonwoven polyester fabric which is capable of stretching both widthwise and lengthwise, the heated fabric will not burn the user's skin, even if applied immediately after removal of the compress 10 from the microwave oven. Because the layer 21 of fabric is expandable, this fabric allows the compress 10 "to breathe" and to have a cool outermost layer 21 which is the only layer to come into direct contact with the user's skin. A sixth advantageous feature of the present invention is that, because the outermost layer 21 is made of breathable fabric eight to ten mils thick, which is twice the normal thickness of most prior art compresses, the sole middle layer 17 of insulative open-cell foam can be substantially reduced in thickness, i.e. compressed, thus reducing the bulk of the entire compress 10 and lowering the packaging costs thereof. In most prior art compresses that have any kind of insulative layer, the outermost layer is usually nonbreathable plastic, thus requiring the Insulative layer to be very thick and rendering the compresses very expensive to package, due to their bulk and the amount of air entrapped therein. Such thick insulative layers are shown in U.S. Patent No. 4,596,250 to Beisang, III et al. and in U.K. Patent No. 1,383,536 to Turner. The foregoing preferred embodiment is considered illustrative only. Numerous other modifications will readily occur to those persons skilled in this particular technology after reading this specification. Consequently, the disclosed invention is not limited to the exact structure and manufacturing method shown and described above, but rather is defined by the claims appended hereto.

Claims: A compress comprising: a bottom wall means (22); a middle wall means (23) positioned above the bottom wall means (22); a first pocket means formed between the bottom wall means (22) and the middle wall means (23); a top wall means (24) positioned above the middle wall means (23); and a second pocket means formed between the middle wall means (23) and the upper wall means (24) for providing a dead air space (18); characterised in that each wall means (22, 23, 24) is a laminate; the middle wall means (23) includes a top layer (17) of insulative material, with the second pocket means providing the dead air space (18) as additional insulation above the middle wall means (23); and the first pocket means contains a gel (14) above the bottom wall means (22). A compress, according to Claim 1, wherein: said bottom, middle and top laminates each have outer peripheral edges that are RF heat-sealed together. A compress according to claim 1 or 2, wherein: the bottom wall means (22) comprises: a first layer (11) of fabric having a top surface; a first layer (12) of adhesive spread on the top surface of the first layer of fabric; and a first layer (13) of plastic adhered to the top surface of the first layer of fabric by the first layer of adhesive; the middle wall means (23) comprises: a second layer (15) of plastic being positioned above the pocket containing the gel, said second layer of plastic having a top surface; a second layer of adhesive (16) spread on the top surface of the second layer of plastic; a layer (17) of insulative material adhered to the top surface of the second layer of plastic by the second layer of adhesive; and the top wall means (24) comprises: a third layer (19) of plastic positioned above the pocket means for providing the dead air space as additional insulation, said third layer of plastic having a top surface; a third layer (20) of adhesive spread on the top surface of the third layer of plastic; and a second layer (21) of fabric adhered to the top surface of the third layer of plastic by the third layer of adhesive. A compress according to Claim 3, wherein: said first layer (11) of fabric, said first layer (12) of adhesive, and said first layer (13) of plastic together form the bottom laminate (22) below the gel (14) contained in the pocket. A compress according to Claim 3 or Claim 4, wherein: said second layer (15) of plastic, said second layer of adhesive (16) and the layer (17) of insulative material together form the middle laminate (23) between the gel (14) and the pocket means (18) for providing the dead air space. A compress according to any one of Claims 3 to 5, wherein: said third layer (19) of plastic, said third layer (20) of adhesive, and said second layer (21) of fabric together form the top laminate (24) above the pocket means (18) for providing the dead air space as additional insulation. A method of manufacturing a compress, comprising the steps of: providing a bottom wall means (22); positioning a middle wall means (23) above the bottom wall means (22); providing a first pocket formed between the bottom wall means (22) and the middle wall means (23); positioning a top wall means (24) above the middle wall means (23); providing a second pocket means formed between the middle wall means (23) and the top wall means (24) with dead air space (18); characterised by: providing each of the wall means (22, 23, 24) as a laminate; including in the middle wall means (23) a top layer (17) of insulative material, with the second pocket means providing the dead air space (18) as additional insulation above the middle wall means (23); and containing a gel (14) in the first pocket above the bottom wall means (22). A method according to Claim 7, including the step of: RF heat-sealing together the bottom, middle and top laminates along outer peripheral edges thereof. A method according to Claim 7 or 8 including, providing the bottom wall means (22) by providing a first layer (11) of fabric having a top surface; spreading a first layer (12) of adhesive on the top surface of the first layer of fabric; and adhering a first layer (13) of plastic to the top surface of the first layer of fabric by the first layer of adhesive; providing the middle wall means (23) by positioning a second layer (15) of plastic above the first pocket, said second layer of plastic having a top surface; spreading a second layer (16) of adhesive on to the top surface of the second layer of plastic; and adhering a layer (17) of insulative material to the top surface of the second layer of plastic by the second layer of adhesive; and providing the top wall means (24) by positioning a third layer (19) of plastic above the pocket means provided with dead air space (18) as additional insulation, said third layer of plastic having a top surface; spreading a third layer (20) of adhesive on to the top surface of the third layer of plastic; and adhering a second layer (21) of fabric to the top surface of the third layer of plastic by the third layer of adhesive. A method according to Claim 9 comprising the further step of: bonding together preliminarily the first layer (11) of fabric, the first layer (12) of adhesive, and the first layer (13) of plastic to form a bottom laminate below the pocket containing the gel (14). A method according to Claim 9 or 10, comprising the further step of: bonding together preliminarily the second layer (15) of plastic, the second layer (16) of adhesive, and the layer (17) of insulative material to form a middle laminate between the pocket containing the gel (14) and the pocket means provided with dead air space (18) as additional insulation. A method according to Claim 9, 10 or 11, comprising the further step of: bonding together preliminarily the third layer (19) of plastic, the third layer (20) of adhesive, and the second layer (21) of fabric to form a top laminate above the pocket means for providing the dead air space (18) as additional insulation.

Inventors: WALASEK STEVEN P, WALASEK STUART J, WALASEK, STEVEN P., WALASEK, STUART J.
Applicants: PACKAGING ELECTRONICS & DEVICE, PACKAGING ELECTRONICS & DEVICES CORP.
Application year: 1990
Main classification: A61F7
IPC codes: F25D3, A61F7, A41D19