AEROSOL DISPENSER VALVE

Abstract

An improved valve member, aerosol dispenser valve containing the valve member, aerosol container for dispensing moisture curable foams, and moisture curable foam and dispenser, in which the valve member is made of a glass filled polyolefin. The polyolefin is preferably a polyethylene. The glass content is between about 2% and about 40%, more preferably between about 10% and about 30%; and most preferably between about 15% and about 25%.

Description

BACKGROUND OF THE INVENTION

This invention relates to aerosol dispenser valves for products, and in particular to dispenser valves for moisture curable products such as foams.

Moisture curable products, such as moisture curable polyurethane foams, have found wide application in homes and businesses. These foams are excellent fillers and insulators. The foams are often packaged in aerosol cans with a polypropylene dispenser valve. A problem with these valves is that moisture can migrate through the valve and into the aerosol can. Once inside, the moisture cures the foam, and impairs the function of the valve. The problem is exacerbated if the can is not stored upright, so that the contents of the can surround the valve member. The migration path is shorter, and when the foam cures around the valve member it interferes with the operation of the valve, sealing it closed.

SUMMARY OF THE INVENTION

A preferred embodiment of the present invention is a dispenser valve for a moisture-curable foam made from a glass-filled polyolefin. In the preferred embodiment the polyolefin is a high density polyethylene. The polyethylene preferably has a glass content of between about 2% and about 40%, and more preferably between about 10% and about 30%, and most preferably between about 15% and about 25%. The valve member of the preferred embodiment is more resistant to failure from moisture infiltration than the polypropylene valve members of the prior art. The valve member of the preferred embodiment is less adhesive than the propylene valve members of the prior art, so that to the extent that the contents of the container does inadvertently cure inside the container, it is less likely to adhere to the valve member and interfere with the operation of the valve. Thus embodiments of valves in accordance with the principles of this invention can extend the shelf life of urethane foams and other moisture curable or moisture affected products dispensed from aerosol cans.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a cross sectional view of a dispenser valve for an aerosol can in accordance with the principles of this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A preferred embodiment of dispenser valve constructed according to the principles of this invention is indicated generally as 20 in FIG. 1. The dispenser valve 20 comprises a valve member 22 in a seal 24. The valve member 22 has first and second ends 26 and 28, and a central passage 30 extending partially therethrough. A plurality of openings 32 extend through the valve member 22 and communicate with the central passage 30. The openings are covered by the seal 24, but when the valve member 22 is deflected, it opens a space between the valve member 22 and the seal 24, so that the pressurized contents can exit the container between the valve member 22 and the seal, through the openings 32, and out the passage 30.

In accordance with the principles of this invention, the valve member 22 is made from a glass-filled polyolefin. The inventors believe that glass-filled polyethylene is more resistant to adhesion than the polypropylene valve members of the prior art, or other suitable polymer materials.

The inventors have also discovered that chemically coupled glass-filled polyolefin, and specific glass-filled polyethylene is less adhesive than the valve members of the prior art, to the extent that the foam does inadvertently cure inside the container, it is less likely to adhere to the valve member and interfere with the operation of the valve.

The polyethylene is preferably a high density polyethylene. The polyethylene preferably has a glass content of between about 2% and about 40%, and more preferably between about 10% and about 30%, and most preferably between about 20% and about 30%.

Thus the valve member of the preferred embodiment are more resistant to moisture infiltration, and less adhesive to moisture curing foams, such as polyurethanes. Thus the valves constructed in accordance with the valve members of this invention are less likely fail, even when the cans on which they are used are not properly stored, and provide a greater product shelf life.

EXAMPLE 1

Cans of moisture curable polyurethane foam components were prepared with valve parts made of different plastics. The cans were stored upside down at ambient temperature and 90-100% relative humidity. Each week three cans of each type were examined and rated on whether the can was fully functional, stuck but functional, or stuck. Failure was determined when all three cans of the sample failed. The results of the test are given in Table 1.

TABLE 1
20% glass-	Impact			Internally
filled	modified			Lubricated
polyethylene	propylene	Polypropylene	Acetal	polypropylene
No failure	Failure	Failure after	Sticking after	Sticking after
after 16	after	5 weeks.	7 weeks;	5 weeks; failure
weeks.	5 weeks.		failure after	after 6 weeks
			9 weeks

EXAMPLE 2

Cans of moisture curable polyurethane foam components were prepared with valve parts made from different plastics. Sixteen cans of each type were stored upside down at 120° at 80% relative humidity for 11 weeks. Cans were inspected at the end of 11 weeks to determine whether the valves were stuck or were functional. The results are given were given in Table 2.

TABLE 2
	Number of	% of stuck
Plastic	stuck valves	valves
50% polyethylene and	0	0%
50% polyethylene with 20% glass
100% polyethylene with 20% glass	2	12.5%
90% polyethylene-	3	18.8%
10% polypropylene with 30% glass
75% polyethylene-	3	18.8%
25% polypropylene with 30% glass
100% polypropylene	4	25%
50% polyethylene-50% polypropylene	5	31.3%
50% polyethylene-	5	31.3%
50% polypropylene with 30% glass
100% polyethylene-	6	37.5%
90% polyethylene-10% polypropylene	6	37.5%
75% polyethylene-25% polypropylene	10	62.5%

This test shows that valves made of glass filled polyethylene (from 10% to 20%) had the lowest number of stuck valves.

EXAMPLE 3

Cans of moisture curable polyurethane foam components were prepared with large valve parts made from different plastics. Twenty-two cans of each type were stored upside down at ambient with caps filled with water. Two cans of each type were tested periodically, and it was noted whether the valve worked, whether the valve was stuck but broke free, or whether the valve failed. The results are given in Table 3.

	TABLE 3
	20% glass-filled
	polyethylene	Polypropylene	Acetal
	No failure after	Stuck but broke	Stuck but broke
	22 weeks.	free, after	free, after 13
		18 weeks.	weeks-failure
			after 22 weeks

EXAMPLE 4

Cans of moisture curable polyurethane foam components were prepared with small valve parts made from different plastics. Twenty-two cans of each type were stored upside down at ambient with caps filled with water. Two cans of each type were tested periodically, to determine whether the valve worked, whether the valve was stuck but broke free, or whether the valve failed. The results are given in Table 4.

TABLE 4
20% glass-	Impact		Ethylene
filled	Modified		Telefluorethylene
polyethylene	Polypropylene	Acetal	polymer (ETFE)
No sticking	Failed, after 8	Stuck but broke	Failures after 19
or failure	weeks.	free, after	weeks
after 22 weeks.		12 weeks; failure,
		after 17 weeks.

EXAMPLE 5

Cans of moisture curable polyurethane foam components were prepared with valve parts made from different plastics. Cans of each type were stored upside down with caps filled with water at 130° F. (to accelerate sticking of the valves). Two cans of each type were periodically tested to determine whether the valve worked, whether the valve was stuck but broke free, or whether the valve failed. The results are given were given in Table 5.

	TABLE 5
	20% glass-filled
	polyethylene	Polypropylene	Acetal
	No sticking	Stuck but broke free	Stuck but broke free
	or failure	after 14 days, failure	after 14 days; failure
	after 51 days.	after 35 days.	after 37 days.

EXAMPLE 6

Cans of moisture curable polyurethane foam components were prepared with valve parts made from different plastics. Cans of each type were stored upside down with caps filled with water at 130° F. (to accelerate sticking of the valves). 20% glass filled polyethylene was compared with impact modified propylene for two different neoprene seal materials. Two cans of each type were periodically tested to determine whether the valve worked, whether the valve was stuck but broke free, or whether the valve failed. Failure was determined when both valves tested stuck or failed. The results are given were given in Table 6.

TABLE 6
Seal 1	Seal 2
20% glass-filled	Impact Modified	20% glass-filled	Impact Modified
polyethylene	polypropylene	polyethylene	polypropylene
No sticking or failure	Failure after 11	Failure, after 21	Failure after 11
after 23 days.	days.	days.	days.

This testing indicates that glass-filled polyethylene provides improved performance with different seal materials.

EXAMPLE 7

Cans of moisture curable polyurethane foam components were prepared with valve parts made from different plastics. Cans of each type were stored upside down with caps filled with water at 130° F. (to accelerate sticking of the valves). 20% glass filled polyethylene was compared with propylene and with a conventional valve using a stick resistant coating on the seal. Two cans of each type were periodically tested to determine whether the valve worked, whether the valve was stuck but broke free, or whether the valve failed. The results are given were given in Table 7.

TABLE 7
		Polypropylene with
20% glass-filled		stick resistant
polyethylene	Polypropylene	seal coating
Stuck but broke	Stuck but broke	Stuck but broke
free after 30 days;	free after	free after
no failure at	22 days; failure	22 days; failure
36 days	after 28 days	after 30 days

This testing indicates that glass-filled polyethylene continued to function after conventional valves and conventional valves with lubricated seals, failed.

EXAMPLE 8

Cans of moisture curable polyurethane foam components were prepared with gun valve (vertically opened) parts made from different plastics. Sixteen cans of each type were stored upside down at 130° with caps full of water. Two cans of each type were tested periodically, and it was noted whether the valve worked, whether the valve was stuck but broke free, or whether the valve failed. Failure was determined by sticking or failure of both cans. The results are given were given in Table 8.

TABLE 8
	First	First
Plastic	Sticking	Failure
100% polyethylene with 20% glass-filled	—	—
polyethylene (ribbed for extra strength)
Impact Modified Polypropylene co-polymer	10 days	—
(ribbed for extra strength)
Polypropylene	13 days	55 days
Acetal	10 days	33 days
Impact Modified Polypropylene	13 days	33 days
Polyethylene	—	26 days*
75% polyethylene-25% polypropylene	10 days
50% polyethylene-50% polypropylene	10 days
100% polyethylene with 20% glass-filled	—	—
polyethylene
Impact Modified Polypropylene	10 days
*stem failure due to weakness of material

This testing shows the superiority of glass filled polyethylene in both ribbed and unribbed configurations.

EXAMPLE 9

Cans of moisture curable polyurethane foam components were prepared with gun valve (vertically opened) parts made from different plastics. Twelve to Fourteen cans of each type were stored upside down at 130° with caps full of water. Cans of each type were tested periodically, and it was noted whether the valve worked, whether the valve was stuck but broke free, or whether the valve failed. Failure was determined by sticking or failure of both cans. The results are given were given in Table 9 below, which shows that some standard valves first stuck after only six days and the standard valves were stuck after 11 days, as compared to the valves with 20% glass-filled Polyethylene valve components which were not stuck after 20 days of testing. All of the 20% glass-filled Polyethylene valve components performed longer than the standard components. The plastic used is a 703 CC chemically coupled 20% glass filled polyethylene available from RTP company, having an impact strength (notched) of about 2.5 ft. lbs./inch and a water absorption of about 0.04 percent.

TABLE 9
Plastic	First Stuck	Valves stuck
100% Polyethylene with	none of 14 samples	no samples stuck
20% glass-filled stems	stuck	after 20 days
Impact Modified	samples first stuck	12 samples stuck
Polypropylene co-polymer	w/in 6 days	w/in 11 days
(ribbed for extra strength)

In the testing conducted, a glass filled polyethylene was always the best performer, and only one other material—acetal—approached the performance of the glass-filled polyethylene in certain circumstances. Glass-filled polyethylene valve stems show surprisingly superior resistance to sticking (i.e. longer times to initial sticking, and longer times to valve failure) over valve stems of other materials in a variety environments, different valve sizes, and different sealing materials. Glass-filled polyethylene even showed superior resistance to sticking than conventional valves with available stick resistance coatings.

While the description of the preferred embodiment and the examples and tests focused primarily on moisture curable foams, and more specifically moisture curable polyurethane foams, the invention is not so limited and the valves and containers with valves of the present invention can be used with other moisture curable products that are dispensed from aerosol cans, and even with products that are not moisture curable, but adversely affected by moisture infiltration.

Claims

1. A valve for dispensing a moisture-curable foam, the valve comprising: a seal; anda valve member, the valve member being constructed to resist adherence of cured moisture-curable foam to the valve member, the valve member comprising a central passage extending partially therethrough, and a plurality of openings extending through the valve member and in communication with the central passage, the valve member being adapted for movement upon actuation between a first position in which the valve member is deflected off of the seal to allow the moisture-curable foam to flow into the central passage, and a second position in which the valve member seats on the seal to prevent flow of the moisture-curable foam into the central passage, the valve member being comprised of a glass filled polyolefin and being more resistant to adhesion to the cured moisture curable foam than the same valve member having no glass content.

2. The valve according to claim 1 wherein the glass filled polyolefin is a chemically-coupled glass filled polyolefin.

3. The valve according to claim 1 wherein the glass-filled polyolefin is a polyethylene.

4. The valve according to claim 3 wherein the glass filled polyethylene is a chemically-coupled glass filled polyethylene.

5. The valve according to claim 3 wherein the glass content is between about 2% and about 40%.

6. The valve according to claim 3 wherein the glass content is between about 3% and about 40%.

7. The valve according to claim 3 wherein the glass content is between about 8% and about 40%.

8. The valve according to claim 3 wherein the glass content is between about 10% and about 40%.

9. The valve according to claim 3 wherein the glass content is between about 2% and about 30%.

10. The valve according to claim 3 wherein the glass content is between about 3% and about 30%.

11. The valve according to claim 3 wherein the glass content is between about 8% and about 30%.

12. The valve according to claim 3 wherein the glass content is between about 10% and about 30%.

13. The valve according to claim 1 wherein the moisture-curable foam comprises at least two liquid components.

14. The valve according to claim 1 wherein the moisture-curable foam is polyurethane foam.

15. The valve according to claim 1 wherein the seal is made of neoprene.

16. An aerosol can for dispensing a moisture-curable foam comprising: an aerosol can;a moisture-curable foam disposed within the aerosol can; anda valve of claim 1.

17. The aerosol can according to claim 16 wherein the glass filled polyolefin is a chemically-coupled glass filled polyolefin.

18. The aerosol can according to claim 16 wherein the glass-filled polyolefin is a polyethylene.

19. The aerosol can according to claim 18 wherein the glass filled polyethylene is a chemically-coupled glass filled polyethylene.

20. The aerosol can according to claim 16 wherein the glass content is between about 2% and about 40%.

21. The aerosol can according to claim 16 wherein the glass content is between about 3% and about 40%.

22. The aerosol can according to claim 16 wherein the glass content is between about 8% and about 40%.

23. The aerosol can according to claim 16 wherein the glass content is between about 10% and about 40%.

24. The aerosol can according to claim 16 wherein the glass content is between about 2% and about 30%.

25. The aerosol can according to claim 16 wherein the glass content is between about 3% and about 30%.

26. The aerosol can according to claim 16 wherein the glass content is between about 8% and about 30%.

27. The aerosol can according to claim 16 wherein the glass content is between about 10% and about 30%.

28. The aerosol can according to claim 16 wherein the moisture-curable foam comprises at least two liquid components.

29. The aerosol can according to claim 16 wherein the moisture-curable foam is polyurethane foam.

30. The aerosol can according to claim 16 wherein the seal is made of neoprene.