Method For The Rapid Assembly Of Diptubes Into Spray Cans And A Diptube Useful Therein

Abstract

Method for the rapid assembly of long flexible diptubes into spray cans wherein the diptube is fixed into a coiled configuration prior to its insertion into the spray can and regains its normal shape after assembly.

Description

BACKGROUND OF THE INVENTION

Pressurized aerosol containers or cans have recently been developed for spraying diverse liquids and many different apparatus have been developed to hold the formulation to be sprayed in the aerosol can until it is released by the consumer.

It has long been a problem in the prior art to provide a flexible or limber diptube for these aerosol containers which will enable one to spray the contents from the discharge opening when the can is held in any position.

U.S. Pat. No. 2,978,152 to Batty illustrates the prior art wherein a long flexible diptube is provided with a weighted end so that the contents of the spray can can be expelled from the can in any position as well as when the contents are almost empty. However, these prior art spray cans having long limber diptubes are relatively hard to assemble on a production line since the operator must take a considerable amount of time to insert the diptube into the can. The present invention solves this problem by providing a long flexible diptube which is coiled prior to insertion into the can. Thus, the coiled diptube can be easily inserted into the spray can prior to the sealing operation and the production rate of the cans is thereby increased.

SUMMARY OF THE INVENTION

The main object of the present invention is to provide an improved method for the rapid assembly of relatively long, flexible, weighted diptubes into a spray can prior to sealing thereof. A further object of the present invention is to provide a coiled diptube which is readily inserted into the spray can during the production of spray cans.

The steps of the present method consist of providing a long flexible diptube having a weighted end and a mounting cup on the opposite end, coiling said diptube intermediate the ends thereof to provide a diptube having adjacent coils in substantial contact, fixing said diptube in coiled relationship so that the diptube can regain its normal shape under suitable conditions after the can is sealed, inserting the coiled diptube into the spray can which is substantially filed with a sprayable liquid and finally sealing the mounting cup onto the spray can. The sealed spray cans are subsequently pressurized with a propellant inserted through the standard valve in the mounting cup. This latter operation is not a part of the present process.

A further object of the present invention is to provide a diptube for use in spray cans which comprises a flexible plastic tube formed into a predetermined number of contiguous coils and means for holding the coils together which is soluble in the contents of said spray can and which is inert to said content.

A still more specific object of the present invention is to provide a coiled diptube for use in spray cans wherein the coil is held together with soluble adhesives or soluble plastic ribbons which form a closed loop around the axial length of said coils.

DETAILED DESCRIPTION

The present invention is illustrated by the drawing in which

FIG. 1 illustrates the sub-assembly of the mounting cup, the coiled diptube and the weighted end.

FIG. 2 illustrates the complete assembly of the elements of FIG. 1 into the final spray can with its contents and propellent after the diptube has uncoiled.

FIG. 3 is an enlarged fragmentary cross-section of the coils of the diptube with the coils held together by a plastic ribbon.

In FIG. 1 the normally long flexible diptube 1 is shortened by providing a plurality of coils as shown. One end of the diptube is secured in a standard mounting cup 4 having an internal valve. The other end is secured in a weight 3 which can be made from any relatively heavy, inert, substance such as metal, glass, or ceramics. The coils are held together in this illustration by a dried or set adhesive 2 to provide the subassembly.

In FIG. 2, the flexible diptube 1 is shown after the coils have been uncoiled inside the pressurized container 5 to provide the final assembled spray can. The sprayable contents 6 are pressurized by a standard propellent shown at 7.

In FIG. 3, the coiled diptube 1 is held in place until it is assembled into the spray can by one or more soluble plastic ribbons 8 which are tied or heat sealed about the axial length of the coiled diptube.

In practicing the method of this invention, the long flexible diptube is wound on a rod having the desired diameter and temporarily fixed into this coiled configuration by freezing it in an ice bath or other low temperature fluids, tying it with soluble plastic ribbons, or applying a soluble adhesive.

It is essential that if adhesives or plastic ribbons are used that they be readily soluble in the contents to be dispensed and at the same time be inert to the active ingredients thereof. This can be readily ascertained by a simple test with each sprayable formulation prior to the insertion of the coiled diptubes. For sprayable formulations using a large amount of water or lower alkanols, it has been found that plastic ribbons or adhesives made from cellulose ethers such as methyl cellulose and ethyl cellulose are satisfactory. Likewise, polyvinyl alcohol adhesives are operable. Other plastic ribbons or adhesives can be readily found by those skilled in the art for different formulations.

Any of the normal propellents such as the Freons or lower hydrocarbons such as isobutane can be used as the propellents in the present invention since these materials are inert to the sprayable formulations.

As a specific illustration of the invention, commercial aerosol valves assembled with their mounting cups and long flexible polyethylene diptubes are each provided with a cylindrical weight on the end of the diptubes. The tubes are then coiled over a cylindrical form and tied together with ribbons of soluble plastic such as ethyl cellulose and methyl cellulose.

The coiled diptubes are then placed in open cylindrical spray cans having diameters of 2 11/16 inches and lengths of 6 3/4 inches, partially filled with 420 grams of a sprayable liquid formulation, crimped in place, pressurized with a propellent and given three shakes. The following table gives the time in which it took the metal weight to contact the bottom of the upright cans which is indicative of the fact that the diptube had uncoiled.

TABLE

Time in Contents Tying Ribbon Can No. Seconds __________________________________________________________________________ Tire traction compo- Ethyl cellulose 1 200 sition* pressurized 2 304 with 80 psi carbon 3 115 dioxide 4 450 5 495 Bathroom Cleaner Methyl cellulose 6 l95 composition** 7 440 pressurized with 80 8 500 psi isobutane __________________________________________________________________________ * Composition consists substantially of methanol with polymerized trimethyl quinoline dissolved therein. See patent 3,27l,170. ** Composition consists substantially of ater with minor amounts of surfactants and chelating agents dissolved therein.

The above cans are used to spray the contents thereof and it is found that they spray well in all positions with no change in the spray pattern in any position. This indicates that the soluble tying ribbons are compatible with the contents and do not interfere with the spraying function.

Similar results to the foregoing are obtained when the coiled diptubes are glued together with an adhesive made from methyl cellulose, ethyl cellulose or polyvinyl alcohol, and are dried in contiguous relationship prior to their insertion into the spray cans.

Claims

I claim:

1. A method for the rapid assembly of relatively long, flexible, weighted diptubes into a spray can substantially filled with a sprayable liquid prior to the sealing thereof, the steps which comprise

1. providing a long flexible diptube with a weighted end, and a mounting cup on the opposite end,

2. coiling said diptube intermediate the ends thereof, to provide a coiled and shortened diptube having adjacent coils in substantial contact,

3. fixing said diptube in coiled relationship with a holding means which is soluble in the contents to be dispensed in said spray can and which is compatible with the contents and does not interfere with the spraying function of said spray can,

4. inserting said coiled diptube into said substantially filled spray can, and

5. sealing said mounting cup onto said spray can.

2. The method as set forth in claim 1 in which the holding means is a soluble adhesive.

3. The method as set forth in claim 1 in which the holding means is at least one soluble plastic ribbon disposed axially about the coils of said diptube.

4. The method as set forth in claim 1 in which the sprayable liquid is selected from the group consisting of water based compositions and lower alkanol based compositions and the holding means is an adhesive selected from the group consisting of cellulose ether adhesives and polyvinyl alcohol adhesives.

5. The method as set forth in claim 1 in which the sprayable liquid is selected from the group consisting of water based compositions and lower alkanol based compositions and the holding means is a ribbon of cellulose ether.

6. A diptube for use in spray cans comprising a flexible plastic tube formed into a predetermined number of contiguous coils, and means for holding said coils together which is soluble in the contents of said spray cans and which is compatible with the contents and does not interfere with the spraying function of said spray cans.

7. A diptube as set forth in claim 6 in which the means for holding said coils together is a soluble adhesive.

8. A diptube as set forth in claim 6 in which the means for holding said coils together is at least one plastic ribbon forming a closed loop around the axial length of said coils.

9. A diptube as set forth in claim 6 which comprises, in addition, a weighted end.

10. A diptube as set forth in claim 9 in which weighted end comprises a metal body through which said tube passes and is permanently affixed.

11. A diptube as set forth in claim 6 which comprises, in addition, a mounting cup on one end thereof adapted to retain said diptube in operative relationship after said mounting cup is sealed onto said spray can.

12. A diptube as set forth in claim 9 which comprises, in addition, a mounting cup on the end remote from said weighted end whereby said mounting cup is adapted to retain said diptube in operative relationship after said mounting cup is sealed onto said spray can.