JPH0249143B2 - - Google Patents

Description

TECHNICAL FIELD This invention relates to aerosol containers, particularly of the fan spray type, for spraying soluble elastomer adhesive polymer solutions. BACKGROUND OF THE INVENTION Small volume applications of elastomeric adhesive materials are most conveniently applied by aerosol spraying. In many applications, if the adhesive is sprayed in an elliptical or fan spray pattern rather than a circular spray pattern,
This convenience increases. This is because the fan mold creates a more uniform application across the width of the spreading mold. Dispersions of elastomeric polymers (eg, cross-linked nitrile rubber, cross-linked butyl rubber, polychloroprene fusion copolymers) were sold in aerosol containers with attached fan spray heads. However, it is desirable to be able to spray elastomeric polymer solutions because spraying creates precipitation problems that solutions do not, and soluble polymers exhibit higher bond strength and withstand higher temperatures better than cross-linked polymers. However, to date the aerosol industry has not been able to commercially produce satisfactory aerosol containers filled with elastomeric adhesive solutions. This is because it has not been possible to obtain a satisfactory spray form from aerosols containing more than a few percent of sticky solids in solution. This is because the polymer structure of the elastomeric adhesive solution has extensive chain entanglement, ie, high solution viscosity. Generally, if the polymer has an average molecular weight of about 10,000 or more and produces a solution with non-Newtonian viscoelastic properties, it has been difficult to spray from an aerosol container. For example, a polychloroprene contact adhesive can be dissolved in a solvent such as methylene chloride and dimethyl
When filled into a pressurized aerosol container with a motive force source such as ether and atomized through an existing fan atomization head, an unacceptably narrow stream release rather than a spray is produced at aerosol solids levels of about 4.4% by weight or higher. can get. A 4.4% polychloroprene adhesive solution packaged within a standard ^475cm3 aerosol will yield approximately 22 grams of adhesive product, i.e. approximately
Gives enough quantity to paint two surfaces with an area of 3.66m ² . Such small quantities of product would not be commercially acceptable since the consumer primarily pays for the container and quickly consumes the contents. As a result, soluble adhesive polymers are difficult to sell in aerosol containers. Therefore, if possible, they are cross-polymerized and sold as aerosol dispersions, or packaged in containers such as cans and tubes that do not have the convenience of aerosol spraying. Industrial users of adhesives have been able to take advantage of soluble adhesive polymers with airless spray gun equipment, which is too bulky and expensive for individual consumer use. These airless spray gun devices are
A spray head is used that has an elongated nozzle opening placed in a groove and a constriction in the material flow path upstream of the nozzle opening similar to that described herein. This structure is described in U.S. Patent No. 2621078, 2683627
3000576, 3647147 and 4097000.
However, such airless spray gun devices typically operate at pressures of 6.9 megapascals or more, compared to typical aerosol container pressures of 0.17 megapascals, and the teachings of the patents listed above
This design has not been shown to be useful for spray heads in aerosol containers filled with soluble polymers and operated at reduced pressure. DISCLOSURE OF THE INVENTION Improved solids levels sprayed with existing spray heads.
When spraying an elastomeric adhesive polymer in solution with a propellant at a 2.5x adhesive solids level,
The present invention provides a spray head that creates a uniform fan spray pattern. A spray head according to the invention has an inlet mandrel inserted into an aerosol container containing a soluble elastomeric adhesive polymer solution and a propellant at relatively low pressure. The inlet mandrel has an inlet passage that communicates with and intersects the outlet tube passage oriented at substantially 90 degrees to the inlet mandrel and terminates in a groove forming an elongated nozzle opening. The nozzle opening thus formed generally has an elliptical cross section;
It has a major axis generally centered within the groove and aligned with the groove that is substantially longer than the secondary axis of the opening. Located between the inlet stem and the nozzle opening is a constriction, which enhances the uniformity of the spray pattern produced by the nozzle opening. In one embodiment, the constriction is formed as part of the spray head and defines an orifice that communicates with the outlet tube. In another embodiment, the restriction defines an orifice or orifices located within the passageway of the outlet tube. A further embodiment of the constriction defines a rectangular orifice located within the outlet tube.

[Brief explanation of the drawing]

The invention will be further described with reference to the accompanying drawings, in which like numbers designate like parts in several drawings, in which FIG. 1 shows a portion of an aerosol container having a spray head assembly according to the invention. 2 is a partially sectional elevation view of the atomizing assembly of FIG. 1, FIG. 3 is an end view of the outlet tube section of the atomizing head of FIG. 1, and FIG. , a partial cross-sectional view taken generally along line 4--4 of FIG. 2; FIG. 6 is a partially sectional elevational view of a third embodiment of a spray head according to the invention showing the orifice plate in solid lines and the additional orifice plate in phantom; FIG. 8 is a partially sectional elevational view of a fourth embodiment of a spray head assembly according to the present invention; FIG. A cross-sectional view taken generally along line 9--9, FIG.
FIG. 11 shows the spray mold after spraying a flat surface made by the spray head without any constriction as represented by FIGS. 6 and 8; FIG.
The spray mold after spraying a flat surface is made by the atomizing head assembly provided with the constriction shown in FIGS. 5, 6 and 8. DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2, there is shown a conventional aerosol container 1 comprising a neck portion 3 and equipped with a valve 5, which is well known in the art. It may be one of the many types known in the art. Valve 5 has a permeation tube (not shown) extending to the bottom of container 1 so that all contents of container 1 are used. A spray head assembly 7 embodying the invention is inserted into the container valve 5 and terminates in a spray head 9 and an elongated nozzle opening 13 through which the contents of the container 1 flow to form a spray 15. and a nozzle outlet tube 11 having interconnected through passages. The spray head 9, best seen in FIG. 2, has an inlet stem 17 and an outlet hole 19 oriented at an angle of about 100 degrees with respect thereto. The inlet stem 17 has a cylindrical wall 21 cut to form a metering gap 23 on its lower side. The inlet stem 17 serves to actuate the container valve 5 when the spray head 9 is depressed, and the metering gap 23 regulates the flow of the contents of the container 1 into the spray head 9. The contents of the container 1 flow through the metering gap 23 into the cylindrical inlet passage 25 formed by the cylindrical wall 21 and into the body 27 of the spray head 9. The passage 25 terminates in a cylindrical chamber 29 which intersects and connects with the outlet hole 19. The above structure is conventional and the most common technical structure. However, if desired, the inlet mandrel 17 may be placed within a spray head 9 having a container valve 5 and a female inlet. Either structure may be used in conjunction with the present invention. Spray head 9 may be machined or molded from any suitable material, including metal or plastic, but is preferably molded from plastic due to cost considerations and ability to withstand chemical attack. 1 to 4 depict a preferred embodiment of the invention in which a constriction 41 defining an orifice 43 is incorporated between the cylindrical chamber 29 and the outlet hole 19. FIG. The constriction 41 is preferably molded integrally with the spray head body 27, but may also be glued or welded in place. The constriction 41 is formed as an annular ring defining a central orifice 43 having a cross-sectional area smaller than either the internal cross-sectional area of the outlet tube 11 or the cross-sectional area of the inlet passage 25 and a cross-sectional area of the nozzle opening 13. Approximately equal to area. The nozzle outlet tube 11 has a cylindrical body part 45 press-fitted into the outlet hole 19 for contacting the constriction part 41 and a flat tip part 47 in which the nozzle opening 13 is formed. The outlet tube 11 may be held in the bore 19 by friction and thus be removable, or it may be glued or welded in place. The nozzle opening 13 is formed by the intersection of a cylindrical passage 49 extending centrally through the outlet tube 11 and a transverse tapered groove 51 . The preferred diameter dimension of the orifice 43 has been empirically determined to be 1.0 mm when used in conjunction with an outlet pipe passage 49 having a diameter of 1.5 mm and an inlet pipe passage 25 having a diameter between 1.5 mm and 3 mm. . Outlet pipe passage 4
The preferred length of 9 is approximately 14.7 mm. Exit passage 4
9 terminates in a conical taper 53 having an included or encompassing angle of approximately 90 degrees, and the nozzle opening 13 is approximately 90 degrees.
A tapered groove 51 having side surfaces 55 and 57 arranged at a 90 degree enclosing angle is formed by transversely intersecting an outlet passage taper 53. Groove 51 extends exit passageway 53 to a depth substantially equal to the length of taper 53.
intersects with The elongated nozzle opening 13 so formed and best visible in FIG. . The preferred opening size is 1.5 mm along the groove 51;
The width is 0.8 mm in the transverse direction to the groove 51. Groove sides 55 and 57 form the terminal surfaces of outlet tube 11. The side surfaces of the groove 51 have flat regions 59 and 61.
It is. The shape of the tip portion 47 of the outlet pipe 11 remote from the groove 51 is such that the spray 1 exiting from the nozzle opening 13
It does not affect the shape of 5. flat local areas 59 and 61
may be tilted away from the groove 51, for example in a concave or convex manner, or may take any arrangement that does not interfere with the groove 51 or the spray 15. However, the grooves 51 extend a distance at least substantially greater than the opening length so that air can enter the grooves 51 and blend with the spray 15 to facilitate dispersion of the spray material;
It also preferably extends over the entire width of the tip 47. The outlet passage 49 preferably terminates in a conical taper 53 as such a shape is easier to form, although the passage 49 may also terminate in a parabolic, hyperbolic or spherical reduced cross-section in side section. good. In the manner described in US Pat. No. 4,097,000, a reduced cross-section that is parabolic in side cross-section and elliptical in cross-section may prove advantageous. However, these shapes are somewhat difficult to form, and if the reduced cross section is conical in side cross section as illustrated,
Very satisfactory results are obtained. FIG. 5 depicts a second embodiment of a spray assembly 63 according to the invention which includes a spray head 65 identical to the spray head 9 illustrated in FIG. The outlet tube 67 is modified to have an outlet chamber 69 which extends from the end 71 of the outlet tube 67 which abuts the constriction 73 defining the orifice 74 and the nozzle opening of FIG. It extends to an outlet passage 75 that connects with a nozzle opening 77 of the same size and shape. The outlet chamber 69, having a diameter of 1.9 mm and a length of 12.7 mm, used in conjunction with the outlet passageway 75 having a diameter of 1.5 mm and a length of 2 mm, was created by the spray head assembly 7 of FIG. It has been found that nearly the same uniform and satisfactory fan spray pattern is produced. FIG. 6 depicts a further embodiment of a spray head assembly 79 according to the present invention having a spray head 81 which has a spray head 41 or 73.
Instead, the constriction is inserted into the atomizing head 81 so that it merely serves to limit the stroke of the outlet tube 85, but is generally similar to the atomizing heads 9 and 65 described above, except with an annular shoulder. It is. The outlet tube 85 has an outlet chamber 87, an outlet passage 89, and a nozzle opening 91, which increase the length of the outlet tube 85;
The outlet chamber 6 of the atomizing head assembly 63 of FIG.
9, identical in all respects to the outlet passage 75 and nozzle opening 77. Centrally along the length of the outlet tube 87 is a diaphragm plate 93 formed as an annular plate defining an orifice 95 coaxial with the outlet passageway 89 and the nozzle opening 91 . The constriction 93 is preferably made of plastic, like the outlet tube 85, and is fixed in the outlet chamber 87 by either a press fit, an adhesive joint, a weld, or a weld. Appropriate dimensions for the aperture 93 and orifice 95 are each a width of 1
mm, with a diameter of 1.25 mm. It has been found that, especially when spraying viscous solutions, providing one or more throttles 93 in the outlet chamber 87 increases the uniformity of the spray pattern. In this case, a plurality of plates 93 (shown in phantom) may be inserted into the outlet chamber 87 and equally spaced along the length of the outlet chamber 87. One and three plates 93 are shown,
Two plates 93 also produce satisfactory results, and if placed symmetrically within the outlet chamber 87 and equally spaced along the length of the outlet chamber 87, three or more plates 93
It is expected that it can also be used. The final embodiment is represented by Figures 8 and 9, which have an outlet chamber 1 with a diameter of 1.9 mm and a length of 22.1 mm.
A spray head assembly 97 is shown including an outlet tube 99 dimensioned to provide a .01. The outlet tube 99 is formed or crimped to form a rectangular orifice 103 whose longitudinal center is 11 from the end of the outlet tube 99 inserted into the spray head 105.
Located in mm. The orifice 103 has a length of approximately 2 mm, and is rectangular in cross section with both rounded ends, as best seen in FIG.
The dimension between flat surfaces 107 and 109 is 0.75 mm. In this case, the dimensions and shape of the associated spray head 105, outlet passage 111, and nozzle opening 113 are the same as those of the spray head 81, outlet passage 89, and nozzle opening 91 of FIG. The embodiment of FIG. 8 is shown to produce a satisfactory fan atomization mold, and may additionally provide the advantage of reduced cost. 10 and 11 illustrate the effect of providing an orifice 43, 74, 95 or 103 in the spray head assembly 7, 63, 79 or 97 between the container 1 and the nozzle opening 13, 77, 91 or 113. represents. FIG. 10 shows that the nozzle opening 13 is
Part of a fan spray mold 115 made by a spray head similar to the spray head in FIG. 2 but without the constriction part 41 that appears when spraying from above onto a horizontal surface with the container 1 held at an angle of about 45 degrees and 150 mm from the surface. It is. The spray mold 115 is characterized by sharply defined thread-like edges or tails 117 on each end and a shallow spray area 119 toward the ends of the mold 115. It was also found that the amount of the sprayed substance became heavier from the bottom toward the top of the mold 115. FIG. 11 shows a fan constructed under the same conditions with spray head assemblies 7, 63, 79, 97 containing any of the orifices 43, 74, 95, 103 represented in FIGS. 2, 5, 6, and 8. It is a spray type 121. The spray mold 121 of FIG. 11 is distinguished from the spray mold 115 of FIG. 10 by the lack of a tail 117 and fewer shallow spray areas 119. One shallow spray region 123 located in the bottom half of the spray mold 121 is generally seen;
has been found to have more atomized material than the shallow atomization region within the atomization mold 115 of FIG. Furthermore, the spray mold 121 created when using the orifice 43, 74, 95 or 103
It has been found that the spray molds are more uniform from edge to edge than spray molds made with spray head assemblies that do not include orifices 43, 74, 95 or 103. Spray mold 115 in Figure 10 and spray mold 1 in Figure 11
The difference between the spray head assemblies 7, 63, 79 described herein is demonstrated by the following example.
97, and a fan spray mold 115 made with a spray head assembly similar to that of FIG. 2 but without the constriction 41. give. These examples are presented to aid in understanding the invention and are not to be construed as limiting its scope. Examples 1-7 A solution of polychloroprene contact adhesive in methylene chloride was prepared using the ingredients and amounts shown below in Table 1. Table 1 Ingredient Weight (grams) 60 to 80 Mooney Viscosity Polychloroprene Copolymer ¹ 6.8 T-Butyl Phenol Resin 3.4 Magnesium Oxide 1.4 Water 0.07 Methylene Chloride 68.4 1 “Neoprene AC” EI Commercially available from Dupont de Nemose. This chemical component was placed in a 475 cm ³ aerosol container 1 and capped with a conventional can valve 5. 24 grams of dimethyl ether are charged into container 1 through valve 5, thereby establishing an adhesive solids level within container 1 of 11.1%. The pressure within the aerosol container 1 reached approximately 0.17 megapascals. The spray head assembly 7, 63, 79, 97 of FIGS. 2, 5, 6, 8 and a spray head assembly similar to that of FIG. 2 but without the constriction 41 are then placed on the container valve 5, container 1 for each
was held at an angle of approximately 45°, and the nozzle opening was held approximately 150 mm from the foil paper placed on a horizontal surface. The same solution above was sprayed onto the foil and allowed to dry, then the spray mold was
It is cut into two equal widths, each representing 20% of the mold dimension transverse to the direction of spraying action. Each width is weighed, the material is removed with a solvent, and the width is dried and reweighed to obtain the initial amount of adhesive material on each width. In this way, the uniformity of the spray molds produced by each embodiment according to the invention was compared to each other and to a spray head assembly without a constriction. The results of these comparisons are listed below in Table 2 and are based on the example number, drawing number and the spray head assembly 7, 63, 79 or 97 and the spray type expressed as a % of the total volume sprayed. Determine the amount of substance in one fifth.

[Front] 1 orifice
(one orifice)

Table A complete spray mold would be each fifth of the spray mold containing exactly 20% of the total amount of material sprayed. Spray head assembly 7, 63, 79 or 97
Although none of the spray head assemblies 7, 63, 79, or 97 including any one of the embodiments of orifices 43, 74, 95, or 103 described above have reached this level of perfection, This example shows that the assembly produces a more uniform fan spray pattern. When spraying soluble elastomeric adhesive polymers at low pressure, the above-mentioned special nozzle opening 1
The 3,77,91,113 arrangement creates a market-acceptable fan atomizer and, as has been demonstrated,
Various embodiments of constrictions 41, 73, 93, 103 increase the uniformity of the spray pattern produced. This spray head structure produces approximately 0.14 and 0.69 megapascals, compared to the approximately 6.9 megapascals required when using an airless spray gun device.
It is possible to spray the polymer adhesive in solution at typical aerosol container pressures of between megapascals. This ability to atomize at low pressures and the incredible difference in pressure is due in part to the fact that the propellant is in solid solution with the adhesive and that some of the propellant is atomized with the adhesive solution. It is caused by Propellants that have been successfully used include dimethyl ether, propane, isobutane, chlorofluorocarbons, and combinations thereof. Other propellants typically used in aerosol applications, such as carbon dioxide or saltpetre, which do not go into solution, produce acceptable spray forms at low adhesive solids levels, but at the desirably high levels described here. This will not produce a satisfactory spray mold. In addition to polychloroprene, other materials that have been successfully sprayed using the disclosed structure are cross-linked nitrile polymers, natural rubber, acrylic resins, butyl rubber, non-cross-linked SBR polymers,
These are cross-linked SBR polymers, butadiene-styrene copolymers, aliphatic cyclic polyesters, and vinyl-vinyl chloride acetate copolymers. Although the invention has been described in connection with specific embodiments,
It is to be understood that the invention is not limited to these examples. In particular, a number of preferred shapes and dimensions have been provided for illustrative purposes only. The invention includes all alternatives and modifications falling within the scope of the appended claims.

Claims (1)

Claims: 1. A spray head assembly 7, 73, 79, 97 having a valve 5 and an inlet stem 17 defining an inlet 23 and slidably and sealably mounted within said valve 5.
, an outlet pipe 11 , 67 , 85 , 99 intersecting said inlet stem 17 and terminating in a nozzle opening 13 , 77 , 91 , 113 ; said inlet 23 and said nozzle opening 13 , 77 , 91 , 113 interconnecting internal passages 25, 49, 75, 8
9, 111, said container 1 comprises said spray heads 7, 63, 79,
In said aerosol container filled at low pressure with a substance that can be sprayed through said nozzle openings 13, 77, 91, 113 by pushing down into said valve 5 said outlet pipe passages 49, 75,
89, 111 and defining the terminal surface of said outlet tube 11, 67, 85, 99, said groove 51 is in contact with said outlet tube passageway 49, 75, 89, 111. Aerosol container, characterized in that the grooves intersect, thereby forming an opening 13, 77, 91, 113, and that the groove is substantially longer than said opening 13, 77, 91, 113. 2 has a cross-sectional area substantially smaller than the cross-sectional area of the passage 25, 49, 75, 89, 111, and the nozzle opening 13, 77, 91, 113 and the inlet 2
Orifice 43, 74, 9 placed between
Aperture portions 41, 73, 93, which define 5, 103,
103. The aerosol container according to claim 1, characterized in that the aerosol container has 103. 3. The aerosol container according to claim 2, wherein the orifice 43, 74, 95, 103 is coaxial with the outlet pipe passage 49, 75, 89, 111. 4 The orifices 43, 74, 95, 103 are connected to the inlet shaft 17 and the outlet pipes 11, 67, 8.
4. The aerosol container according to claim 3, wherein the aerosol container is arranged between 5 and 99. 5 disposed within the outlet pipe 67, 85, 99 coaxially with the outlet pipe passage 75, 89, 111;
an outlet chamber 69,87 having a cross-sectional area substantially larger than the cross-sectional area of the outlet pipe passageway 75,89,111;
101. The aerosol container according to claim 2, characterized in that the container has a diameter of 101. 6 the orifice 74 is coaxial with the outlet pipe passage 75 and is arranged between the inlet pipe 17 and the outlet pipe 67, and the outlet chamber 69 extends to the constriction 73 so that it directly connects the orifice 74;
Claim 5 is characterized in that it communicates with
Aerosol containers as described in section. 7. The aerosol container of claim 5, wherein the orifice 95 is coaxial with the outlet pipe passageway 89 and located within the outlet chamber 87. 8 the constriction 93 is coaxial with each other and the outlet pipe passage 89 and further defines a plurality of orifices 95 disposed within the outlet chamber 87 and equally spaced from each other along the outlet chamber 87; The aerosol container according to claim 5, characterized in that: 9. Aerosol according to claim 5, characterized in that the orifice 103 has a substantially rectangular cross-sectional area and is located within the outlet chamber 101 and is centered with respect to the cross-sectional area of the outlet chamber 101. container. 10 The orifice 43, 74, 95 or the orifice 95 is connected to the nozzle opening 13, 7.
8. Aerosol container according to any one of claims 4, 6, 7 or 8, characterized in that it has a circular cross-sectional area substantially equal to the cross-sectional area of 7,91. 11 The groove 51 is connected to the outlet pipe 11, 67, 8
Claims 1 to 1, which extend over a width of 5.99 mm and have an open end.
The aerosol container according to any one of item 0. 12. The groove 51 has a V-shaped cross section and side surfaces 55 arranged at a bevel angle of 40 degrees to 120 degrees,
57, the aerosol container according to any one of claims 1 to 11. 13 The outlet pipe passage 49, 75, 89, 111
terminate in a conical taper intersecting said groove 51, thereby forming nozzle openings 13, 77, 9 with a shape corresponding to two oblique intersecting parabolas.
13. Aerosol container according to claim 12, characterized in that it forms 1,113. 14. The aerosol container according to any one of claims 1 to 13, characterized in that the substance is mixed with a soluble propellant, a part of which is sprayed together with the substance. 15 Soluble propellants in said substances are dimethyl ether, propane, isobutane, trifluoromethane trichloride, difluorine methane dichloride, trifluoride methane chloride, fluorine ethane dichloride, difluorine methane chloride, trifluoride trichloride. 15. The aerosol container of claim 14, wherein the container is selected from the group consisting of ethane and tetrafluoroethane dichloride.