BACKGROUND

Aerosol dispensing containers have found widespread use in the packaging of fluid materials including a variety of both liquid and powdered particulate products. Such containers are provided with a valve-controlled discharge orifice and operate by the action of a volatile propellant which is confined within the container together with the product to be dispensed. Because the propellant has an appreciable vapor pressure at room temperature, the product in the closed container is maintained under super-atmospheric pressure.

A typical aerosol unit comprises a hollow cylindrical container which is tightly closed at one end and is provided with an opening at its opposite end for receiving a dispensing valve assembly. A closure, commonly referred to as a mounting cup, serves as the closure for the container and as a support for the valve assembly. Typically, the mounting cup comprises a panel having an aperture for receiving the valve assembly, a skirt depending from the periphery of the panel, and an annular channel extending outwardly from the edge of the skirt.

SUBSTITUTE SHCEP

hen the mounting cup is placed in sealing position on the container, the channel is positioned over the bead surrounding the container opening and the lower portion of the skirt adjacent to the channel is flared outwardly against the container wall adjacent the bead. To ensure adequate sealing between the closure and the container, the cup is provided with a gasket.

Heretofore, mounting cup gasket seals have been formed by disposing a previously cut gasket in the channel. This type of gasket has the disadvantage of not being stationary relative to the mounting cup during propellant filling or other valve unit assembly operations with the undesirable consequence that when the mounting cup and container are clinched to effect the seal, the gasket is often disposed at an angled position, and thus, the clinching operation is less effective.

Another commercial method for forming the gasket onto the mounting cup consists in forming the gaskets, in situ, from liquid gasket-forming compositions comprising an elastomer dispersed or dissolved in a volatile organic liquid vehicle. In the manufacture of such a gasket, the liquid composition is deposited in the desired configuration in the channel of the cup while the cup is rotated ^" beneath a metering nozzle through- which-the composition flows. The deposit is then converted into a dry solid sealing mass by expelling the liquid vehicle at elevated temperatures. Though this technique of flowing gaskets into place has received wide commercial acceptance, it suffers from the disadvantages of requiring an elaborate drying operation, wherein the mounting cup must be handled carefully so as to avoid undue upset from the

^S UBSTITUTE SHEξT

horizontal; costly recovery apparatus for the expelled organic liquid also must be provided. In sum, the flowed gasket is an expensive step in the formation of the mounting cup. See U. S. Patent No. 3,342,381 as an example of the "flowed ¹ * gasket.

Other techniques for disposing a gasket onto the mounting cup are described in U. S. Patent No. 3,417,177, wherein the gasket seal is made of heat shrinkable material. After placing a band of gasket material on the skirt, the gasket having a greater diameter than the outside diameter of the skirt of the mounting cup, the cup is heated at a temperature and for a time sufficient to shrink the band into tight frictional engagement with the skirt.

Another similar technique is that disclosed in U. S. Patent No. 3,443,006, wherein a band of gasket material is swelled through the use of a suitable swelling agent so as to increase its diameter to fit over the skirt of the mounting cup. Subsequently, the swelling agent is removed from the gasket material so that the band will come into tight frictional engagement with the skirt.

Both the heat shrink and swelling techniques for applying a gasket material to the mounting cup have the disadvantage of being costly and relatively time consuming procedures. Note in U. S. 3,417,177, column 4, lines 27-31, that the positioned bands must be heated to 240°F for about 2-3 minutes in order to obtain a tight friction fit. In the procedure of 3,443,006, the bands must stand in the swelling liquid for a period of 1/2 to 1-1/2 minutes according to Example 2 of the '006 patent and then allowed to stand for the drying period. Also, in any mass

£_■ UBSϊT ^. TUTE

production utilizing the '006 system, an organic liquid recovery system must be employed.

In United States Patent Application Serial No. 565,873, filed December 27, 1983; which application is a continuation of Serial No. 332,510, filed December 21, 1981; Serial No. 332,510 being a continuation of Serial No. 112,791, filed February 1, 1980, is described a novel gasketed mounting cup system, including novel method and apparatus, wherein the gasket material is disposed on the mounting cup in the desired position for effecting a seal between the mounting cup and the bead of the container; and further wherein the disadvantages associated with the aforementioned techniques' of applying the gasket material to the cup are obviated. Also, an apparatus and method is. provided wherein gaskets are applied,to aerosol mounting cups in an exceptionally rapid and efficient manner to form gasketed-mounting cups having excellent sealing characteristics.

In general, the method of the invention of the aforesaid U. S. Serial No. 565,873 comprises passing a tubular sleeve of gasket material onto a compressible mandrel; initially positioning and aligning the skirt of the mounting cup and the contiguous end of the mandrel such that the sleeve of gaske material may pass onto the skirt, said mandrel having fixed and movable portions with respect to each other and to their movement toward and away from the mounting cup; urging the movable portion of the gasket material bearing mandrel toward the mounting cup such that the gasket material passes onto the skirt of the cup; causing the movable portion of the mandrel to retract to its initial position, cutting the sleeve at a point between the mounting cup and s UBSTITUTE SHEET

the mandrel to leave a band of gasket material; and subsequently, advancing the mounting cup to a station whereat the band of the gasket material is urged further onto the skirt of the mounting cup, whereby, the band of gasket material does not extend beyond the skirt of the mounting cup. Thereafter, the gasket is further advanced to its final position on the mounting cup.

For certain applications of the gasketed mounting cups of Serial No. 565,873, namely, utilizing said mounting cups in so-called "under the cup" propellant filling of the container, it has been observed that on limited occasions the gasket band was removed from the mounting cup during the filling operation. Moreover, observation revealed a tendency in an untoward number of gasketed mounting cups for the band of gasket material to recede from its initial placement position in the channel or curl portion of the mounting cup before crimping the mounting cup to the container. Both of these disadvantages reduce productivity.

An improvement in the method and apparatus utilized in the aforesaid Serial No. 565,873 and the cup produced thereby is set forth in United States Patent Application Serial No. 606,547, filed May 3, 1984, a continuation of Serial No; 302,442, filed September 18, 1981.

In general, the product of the invention of Serial No. 606,547 comprises disposing one or more compressive deformations in the band of gasket material. Serial No. 606,547 discloses that a series of radial or annular deformations (ribs) may be utilized. s ^' t

'B3TJTUTE SHEET

hile the improvement of Serial No. 606,547 has resulted in a substantial alleviation of the problems referred to above regarding gasket removal and recession, it has been observed that the placement of the gasket on the mounting cup relative to the outer edge of the cup, and concomitantly the placement of the gasket along the skirt of the cup, has varied from production run to production run. This variance is undesirable.

SUMMARY OF INVENTION

The subject invention concerns an improvement in the gasketed mounting cup of Serial No. 606,547 (referred to supra). In general, the improvement in the gasketed mounting cup of the subject invention comprises a multiplicity of radially-directed deformations in the band of gasket material contiguous to the channel portion of the mounting cup. The radially directed deformations form an annular, alternating series of relatively thick and thin gasket portions. In a preferred form, the radially-directed deformations terminate within the outer edge portion of the gasket.

The present invention will be more clearly understood by referring to the drawings herein and the discussion relating thereto.

In the drawings:

Figures 1-14, both in the drawings and the descriptive matter of the specification referring thereto, set forth subject matter from Serial No. 565,873, said subject matter not forming a part of the

- ^■ -•<.-r«t_T_ I _{j t}

claimed invention herein. Figures 15 to 32 concern the claimed subject matter of this invention.

Figure 1 shows in section view a gasketed aerosol mounting cup prepared according to the method and apparatus of the invention of Serial No. 565,873.

Figures 2A-F is a schematic of one embodiment of the invention of Serial No. 565,873, showing the several steps utilized in positioning the gasket material onto an aerosol mounting cup.

Figure 3 is a perspective view of the apparatus of the embodiment of Figure 2, together with the apparatus used in a second operation novel to this invention, on the product of the embodiment of Figure 2.

Figure 4 is a sectional view of the apparatus of the embodiment of Figure 3, along the line 4-4 of Figure 3.

Figure 5 is a partial section of the apparatus used in the second operation of the product of the embodiment of Figure 2, along the line 5-5 of Figure 3.

Figure 6 is a timing diagram through a single cycle for producing the mounting cup according to the embodiment of Figure 2.

Figure 7 is a schematic showing the several operations or stations in the preferred mode for the manufacture of the gasketed mounting cup of this invention.

Figure 8 is a partial sectional view of the preferred apparatus used in the operation to advance the band of gasket material onto the mounting cup such that the end of the gasket material resides on the straight portion of the skirt of the mounting cup.

Figure 9 is a perspective view of one of the flexible fingers of the apparatus of Figure 8.

^SU BSTITUTE SHEET

Figures 10 and 11 are a plan view along the lines 1Q-10 and 11-11 of Figure 8.

Figure 12 is a plan view along the line 12-12 of Figure 8.

Figure 13 is a partial sectional view of the preferred apparatus used in the operation to advance the gasket material to its ultimate position on the mounting cup.

Figure 14 is a plan view of the top surface of a member of the centering mechanism of Figure 13.

Figure 15 is a plan view of the underside of the gasketed mounting cup of this invention.

Figure 16 is a sectional view of the gasketed mounting cup of Figure 15.

Figure 17 is a plan view of the underside of the gasket of this invention.

Figure 18 is a sectional view- of the gasket of Figure 17.

Figure 19 is an enlarged section along the line A-A of Figure 17.

Figure 20 is an enlarged section along the line B-B of Figure 17.

Figure 21 is a partial section of the plunger used to form the gasket of Figures 15-20.

Figure 22 is a partial section of the inner sleeve of the plunger of Figure 21.

Figure 23 is an enlarged view of the circled portion of Figure 22.

Figure 24 is a plan view of the underside of a further embodiment of the gasketed mounting cup of this invention.

Figure 25 is a sectional view of the gasketed mounting cup of Figure 24.

Figure 26 is a plan view of the underside of a further embodiment of the gasket of this invention.

s SUB

Figure 27 is a sectional view of the gasket of Figure 26.

Figure 28 is an enlarged view along the line A-A of Figure 26.

Figure 29 is an enlarged view along the line B-B of Figure 26.

Figure 30 is a partial section of the plunger used to form the gasket of Figures 24-29.

Figure 31 is a partial section of the inner sleeve of the plunger of Figure 30.

Figure 32 is an enlarged view of the circled portion of Figure 31.

Figure 1 is a sectional view of a gasketed-mounting cup shown in inverted position relative to its placement on the assembled container and produced according to the general method of Serial No. 565,873. The mounting cup, generally designated as 10, comprises a circular panel 12 having an integral skirt 14 depending from its periphery. The free edge of skirt 14 is outwardly flanged at 16 to form an annular channel 18 for embracing the bead surrounding the container opening (not shown), when the cup is positioned thereon. The inner portion of panel 12 is countersunk to form a tubular rim, generally designated as 20, which has a dependent circular wall 22 integrally joined with an apertured horizontal wall 24. When the cup is placed in sealing position, the rim 20 acts as a pedestal for the valve unit and the valve stem is admitted into the container through apertured wall 24. The gasket 26 is disposed on the exterior surface of the skirt 14 and extends beyond the juncture of the skirt and channel and a distance into said channel.

StJ SfTT TE SHEET

In Figures 2A-F, corresponding parts in each figure are as numbered and described in Figure 2A, said figures showing a schematic of the relative positioning of the moving components of the apparatus at each stage of the cycle in advancing a plastic gasket material onto a mounting cup and cutting the tube to ultimately provide a band of gasket material disposed on the skirt of the mounting cup.

In Figure 2A, a sleeve of gasket material 30 is disposed over the length of the mandrel, generally designated as 32. Mounting cup 34 is securely positioned within a seat 36, which is mounted on a suitable base, in a manner known to those skilled in the art. Positioning pin 38 extends through the central aperture in the pedestal of the mounting cup 34 and provides a fixed spacing between the bottom surface 40 of the mandrel 32 and the mounting cup 34. Mandrel 32 has an upper portion 42 and a lower portion 44 which are retractably collapsible relative to each other (the structure of which is more fully described in Figure 4). An upper and lower gripping member is provided at 46 and 48, respectively.

Figure 2A, the initial stage of a single cycle, shows the mandrel 32 disposed atop the positioning pin 38, with the mandrel 32 having the gasket material disposed at the. initial cycle stage, i.e., terminating at the bottom surface 40 of the mandrel 32. Both gripping members, 46 and 48, are in an open position.

In Figure 2B, the upper gripping member 46 closes about the mandrel 32 and subsequently moves the upper portion 42 of the mandrel 32, toward the mounting cup 34. By this motion, the gasket material

" ^f cttTITUTE SHEET

30 is moved past the stationary bottom surface 40 of the mandrel 32. Both gripping members, 46 and 48, are in an open position.

In Figure 2C, the gasket material is first disposed on the skirt of the mounting cup 34 the desired distance, and subsequently, the lower gripping member 48 engages the lower portion 44 of the mandrel 32.

At the next stage of the cycle. Figure 2D, the upper gripping member 46 releases allowing the upper portion 42 of the mandrel 32 to return to its original position. Concomitantly, the positioning pin 38 is lowered beneath the mounting cup 34 and thereafter a cutting edge 50 (shown only in Figure 2D) is passed through the gasket material 30.

Figure 2E shows a mounting cup with a band of the gasket material 30 on the skirt of the mounting cup.

At the next stage. Figure 2F, the bottom gr-ipper 48 is closed on the bottom portion 44 of the mandrel 32 and positioning pin 38 is moved to the position shown in Figure 2A, after which the gripper 48 is released and the system is at the initial stage shown in Figure 2A. - -

Figure 3 shows a six-station gasket-mounting cup assembly. The gasket material 30 is fed from individual rolls (not shown) of said material. Upper gripping member 46 has a series of openings 52 which receive the mandrel 32. The bottom gripping member is 48. Mounting cup 34 is fed through a raceway 54 to a position beneath each of the mandrels 32. Not shown

sy ^; I ^β TΪTUTE SH -f

for the reason that it is known to those skilled in the art, is the structure which transports, here six, a given number of mounting cups along the raceway 54 to their respective positions in vertical alignment; with each associated mandrel. In the timing chart of Figure 6, these structures are referred to as the feed finger, feed arm and locator device. Cutting edge 50 is mounted onto a rotating wheel 56 in such a manner as to impart an elliptical motion as the cutting edge advances and retreats during the cutting cycle.

After the mounting cup has received the gasket material 30, the cup is moved to a station whereat a hollowed bottom plunger 58, shown in more detail in Figure 5, advances over the skirt of the mounting cup and urges the gasket material 30 along the skirt.

Figure 4 shows in more detail the structure of a single mandrel-mounting cup station of the embodiment shown in Figure 3. The upper portion 42 of the mandrel 32 has a tapered upper surface 60 which is threaded onto the upper portion 42, the shape of the surface 60 facilitating the passing of the gasket material onto the mandrel 32. Further, the upper portion 42 of the mandrel 32 has a cavity 62 in which is disposed a spring 64. Shown best in Figures 2A-F are the plurality of fingers ^* 66 which form-the-bottom end of the upper portion 42 of the mandrel 32, and the plurality of recesses 68 in lower portion 44 of the mandrel 32, and which are aligned to receive the fingers 66 when the upper portion of the mandrel 32 is moved toward the lower portion of the mandrel.

The upper gripping member 46 is a conventional chuck which is connected to a

reciprocating ram such that it may rapidly advance and retreat from the mounting cup and when gripping the upper portion of the mandrel move said portion toward the mounting cup.

The lower gripping member 48 is a convention¬ al chuck. The cutting edge 50 is mounted in a conventional manner and proscribes an elliptical path in its advance and retreat from the mounting cup 34.

Figure 5 shows a reciprocating plunger, the lower outer shoulder of which engages the upper edge of the gasket material and urges it further onto the skirt of the- mounting cup. In Figure 5, the plunger, generally designated as 104, has a lower hollow portion 106, terminating in shoulder 108. Set within the lower portion 106 is a spring-loaded centering- pin 110 having the protuberance 112. The protuberance 112 has the beveled terminating portion 114 which mates with and centers the mounting cup 34 by contacting the sloped panel 113 of the mounting cup.

The function of the plunger action shown in Figure 5 is to advance the band of gasket material onto the mounting cup such that the band resides at or below the sloped surface 113 of the mounting cup 34. The purpose of so disposing the gasket band is to provide a band edge supported against the straight portion 115 of the skirt of the mounting cup 34, thereby to be properly positioned to mate with the plunger in the second and final plunger action for advancing the band of gasket material to its ultimate position on the mounting cup.

Figure 5 shows means for advancing the gasket material from its position on the mounting cup after

SUBST

-14- cutting of the gasket tubing to the position shown in Figure 8. From the plunger station of Figure 5 the mounting cup is moved, after heating, to the final plunger station.

The advancement of the plunger and mounting cup centering of Figure 8 is through the simple action of advancing the reciprocating ram, which action is a conventional means for advancing the plunger and centering means. The action of the plunger of Figure 5 is simple advancement of the plunger through movement of the reciprocating ram.

The preferred plunger configuration for initially advancing the band of gasket material further onto the mounting cup is shown in Figures 8-12. In Figure 8, the plunger generally designated as 200 has an arbor 202 which is connected through conventional means to a reciprocating ram (not shown). Within the bore 204 telescoped member 206 is independently spring loaded within the bore 204. The telescoped section 206 terminates in a slotted collar portion 220. Positioned within member 206 is mounting cup centering means 208, which is independently spring loaded. Slotted collar 210 is disposed outboard of telescoped section 206, the slots of said collar 210 receiving fingers 212. The fingers 212 (shown in more detail- in -Figures 9) are affixed to the arbor 202 through dowel pins 214. The slots 216 (Figure 9) receive 0 rings 218, the purpose of the 0 rings being to provide a constant inwardly directed pressure on the fingers 212. The fingers 212 are also positioned within the slots 222 (Figure 11) of the slotted collar portion 220. Affixed to the bottom of telescoped member 206 is a plate 224, said plate 224 providing a shoulder 226 against which the bottom shoulder 228 of

S ³ _ OT3TUT£ SHEET

the fingers 212 abut during the advancement of the plunger 200. The distance that the fingers 212 travel before meeting the shoulder 226 determines the distance that the gasket 230 will be advanced onto the skirt 232 of the mounting cup 234. Threadedly mounted onto the slotted collar 210 is an outer adjustable sleeve member 236 which sleeve member 236 functions to prevent outward splaying of the fingers 212 and thereby to direct the bottom surface 238 of the fingers 212 against the top surface of the gasket material 230.

Figure 6 describes a timing cycle that is suitable for the six-station unit shown in Figure 3. In Figure 6, the clamp is the gripping member, pins the positioning pins, feed finger and feed arm are a conventional mechanism for advancing six mounting cups per cycle to be positioned to receive the gasket material.

Subsequent to the initial advancing of the band of gasket material onto the skirt of the mounting cup, the cups are passed through a heating zone to heat the gasket material. For example, heating of the gasket material may be accomplished through con¬ tacting of the gasket bearing metal mounting cup and the metal tracking through which the cup passes; the metal track being heated b -a-contained- heated, liquid.

Alternatively, and the preferred method of heating the gasket material, may be accomplished by initially heating the metal mounting cup through induction heating by passing the gasket bearing cup in the vicinity of a magnetic field and subsequently passing the cup through a heated track as described above.

SUBSTITUT SHEET

It has been found that pulsing the cups moving at a rate of ^' 520" per minute through a magnetic field created by 0.28 amps and subsequently indirectly heating the cups with a liquid at a temperature bet¬ ween 192°F-210°F produces a satisfactory heating of the gasket material to enable the gasket material to be advanced to the final position on the mounting cup.

From the heating zone the gasketed mounting cups are passed to the secondary plunger station. The plunger and plunging action at the secondary plunger station is shown in Figure 13.

The preferred plunger used at the secondary plunger station for effecting the radially-directed deformations of the gasketed mounting cup of this invention in the two-step advancement of gasket material to its ultimate position on the mounting cup is as shown in Figures 21-23 and 30-32.

In Figure 13 is shown a plunger mechanism, generally designated as 240, which initially centers the mounting cup 242 and subsequently advances the gasket 244 to its ultimate position on the mounting cup 242. The plunger mechanism 240 is attached to an arbor (not shown) which in turn is attached by conventional means to a reciprocating press (not shown). The plunger mechanism has a plug member 250. which has a central bore defining a chamber 252. Affixed to the plug member 250 is inner sleeve 254, said sleeve having a flange 256 for connecting to the plug member 250.

Outer sleeve 258 is connected to inner sleeve 254 through flange 260.

SUBSTITUTE SHEET

Centering mechanism, generally designated as 262, is disposed within the inner sleeve 254 and the chamber 252 and comprises a spring retainer and stop 264, rod 266, piston member 268, 0 rings 270 and centering plug 272.

Mounting cup stripper 274 is independently spring loaded and is assembled within the inner sleeve 254 and rests on shoulder 276 of inner sleeve 254. The opening 278 of the stripper 274 has a slot configuration which is shown in greater detail in Figure 14. The slot configuration prevents the centering mechanism from being removed from the plunger assembly, the edge 280 of the spring retainer and stop 264 abutting against the upper surface 282 of the stripper 274.

The configuration of the forward advancing surface of the plunger to effect the radially-directed deformations is best shown in Figures 21-23. In Figure 21 the forward advancing surface 284 of the inner sleeve 254 comprises a multiplicity of spaced V-cuts to provide an annular pattern of alternating flats 286 and V-shaped recesses 288. An enlarged detail showing of the flats 286 and V-shaped recesses 288 in the plunger surface 284 is shown in Figure 23.

- The configuration of the deformations formed in the gasket is shown in Figure 19.

In Figure 15, the gasket, generally designated as 300, is shown seated in the mounting cup 302. Note that the deformations 304 terminate short of the peripheral edge 306 of the gasket.

SUBS

It has been found that when using a gasket material having a thickness of .014", effecting an annular radially-directed deformation wherein the thin portions are .008" and thick portions are .020" provides a satisfactory product.

As shown in Figures 15 and 17, the annular deformation comprises a series of eighty (80) alternating thin and thick portions of gasket material. This is the preferred configuration. It is believed that the minimum number of thin and thick portions to effectively positionally stabilize the gasket is forty (40).

Further, it is preferred that the annular radially-directed deformation of thin and thick portions be evenly spaced and of equal width, as shown in the drawings. In addition to positional stability, it is believed that the raised compressible portion of the gasket ("high spots"), best shown in Figure 19, act as a series of springs urging the mounting cup away from the annular clinching contact between the mounting cup and container bead (clinching between container and mounting cup not shown but standard practice is to outwardly swage the skirt of the cup against the inner surface of the container bead) thereby effecting an improved seal between cup and container.

In another embodiment, shown in Figures 24-27, a bead 400 is formed on the perimeter of the gasket 402.

The bead 400 may be formed by using a forward advancing plunger surface configured with a recess 404 in the outer plunger sleeve 406, as shown in Figure

30. With a gasket thickness of .014", a recess 404 of .050" has been found satisfactory.

In operation, with either embodiment of the secondary plunger the centering mechanism 262 is advanced toward the mounting cup by passing air under pressure into the chamber 252, said advancement occurring at the initial phase of the downward stroke of the reciprocating press. The air passes through the slot of the stripper 274 and generates a pressure against the piston 268 which overcomes the retracting pressure of the spring 287 and advances the centering mechanism against the mounting cup. Before the advancing sleeves contact the gasket, the centering mechanism is retracted by closing off the air supply and allowing the spring to return the mechanism to its retracted position. .The plunger sleeves continue their advance and shoulder 290 engages the gasket and urges the gasket further onto the mounting cup. The inner and outer sleeves ultimately bottom in the channel of the mounting cup. During this bottoming action the inner sleeve effects a compressive force against the plastic gasket material and the gasket is deformed in the pattern of the forward advancing surface 284, thereby permanently deforming the surface of the gasket. After advancing and bottoming the plunger, the sleeves are retracted while retaining the stripper in contact with the mounting cup through - its independent spring means for a portion of the retraction cycle, namely, until the inner sleeve clears the mounting cup. Subsequent to the plunger action, the mounting cups are promptly preferably cooled to about 40°F.

To form a friction fit between gasket material and the skirt of the mounting cup, the inside

diameter of the sleeve of the gasket material is slightly less than the outside diameter of the skirt portion of the mounting cup. Conventionally, the so-called one-inch aerosol mounting cups have a skirt diameter of ".980-.990". It has been found that •gasket material having a thickness of .014 is satisfactory. To accommodate this thickness of gasket, mounting cups having a skirt diameter of .950 inches have been used. Gasket bands having a width of 9/32" have been satisfactorily employed.

To produce a gasketed mounting cup closure according to this invention for a one (1) inch container opening (predominant opening size for commercial aerosol containers), it has been found that having the gasket material of .G14" thickness extend onto the skirt of the mounting cup a distance of .160"-.185" from the top of the mounting cup (cup in position on container) produces a satisfactory product.

" While any plastic gasket material having sufficient resiliency may be used, provided there is compatability between the container contents and the plastic material, it has been found that a plastic comprising low density polyethylene (density range of .916-.922) having 5-15% polyisobutylene in the molecular- weight range of 40,000-200,000, plus stabilizers usually used with polyethylene in the environment in which the gasket material will reside, provides a satisfactory gasket material over a broad product range.

§UBST_TUTE SHEET