EP0315880A2

EP0315880A2 - Dispensing device

Info

Publication number: EP0315880A2
Application number: EP88118192A
Authority: EP
Inventors: Dorinda Sparacio
Original assignee: Colgate Palmolive Co
Current assignee: Colgate Palmolive Co
Priority date: 1987-11-09
Filing date: 1988-11-02
Publication date: 1989-05-17
Also published as: AU2472288A; EP0315880A3; NZ226794A; NO884975D0; DK623288A; ZA888216B; JPH024677A; NO884975L; DK623288D0

Abstract

A dispensing device or pump for viscous and other fluent material such as toothpaste or food, wherein part or all of the components are made of a terpolymer of ethylene, propylene and diene, most preferably material of that type sold by Monsanto under the Trademark "Santoprene". Such a material has a better flexibility and a lower flavor absorption than the materials commonly used for this type of dispenser.

Description

FIELD OF THE INVENTION

Pumps and similar devices for dispensing viscous and fluent materials.

BACKGROUND

This invention relates to dispensing devices for fluent and viscous materials, particularly pumps of the hand-held type. Such hand-held pumps are enjoying increasing popularity for dispensing a wide variety of products, such as creams, lotions, mayonnaise, cheese and other foods.
In recent years, the use of hand-held pumps to dispense dentrifice has grown rapidly, and such pumps are now preferred by many consumers over the prior art tubes for toothpaste.
The development of toothpaste pumps has, therefore, become increasingly rapid, as manufacturers seek more efficient, less complicated and less expensive devices.
Hand-held pumps for toothpaste and the other materials referred to above are, per se, not new in the art in the sense that there are numerous prior art developments. Generally speaking, patent disclosures of such prior art devices are placed in International Classes B05B 11/04; B65D 37/00 and G01F 11/00 and are now stored in Class 222 in sub-classes 383, 385, 386, 401, 207, 209, 212, 256, 259, 260, 340 and 341 in the U.S. Patent Office. Recently granted patents which exemplify the art are U.S. Patents 4,437,591; 4,511,068 and 4,598,813.
Of the earlier patents in the art, U.S. 3,255,935 is well representative.
One type of pump now on the market has certain basic components, including a dispensing orifice, a piston assembly for forcing the material to flow, and an actuator for the piston, which usually includes a rod passing through the piston. Certain of these pumps also have valves for opening and closing the flow of the material to the orifice. Pumps of this type might be termed "piston rod" pumps. A representative patent of this type is U.S. Patent 4,437,591.
Another type of pump now sold might be called "rodless" pumps. That is, they do not have a rod connected to the piston and typically the piston is drawn up toward the top of the pump pushing the contents above it by vacuum pressure which is created by a flexible bellows head as exemplified by U.S. Patents 4,413,759 and 4,474,313.
In the art as it has developed, the foregoing components have been designed in a variety of ways. Further, it is possible that future developments in this art will be such as to eliminate some of the aforesaid components, or alternatively, to use other components which nevertheless enable the pump to perform its task of dispensing toothpaste and similar products.
Whatever the present or future design of pump components may be, it has recently become apparent that the materials from which the components are made can have certain disadvantages. More specifically, the most common materials are polyethylene terepthalate (PET), polypropylene (PP) and polyethylene (PE) and combinations thereof. These plastics have many good properties for this type of use: e.g., they can be molded, are relatively strong and therefore provide excellent shipping, handling and impact resistance and, of course, are currently in plentiful supply.
However, certain pump components made with PP, PE, PET and other currently employed materials have disadvantageous properties: e.g., they are relatively inflexible and have a high flavor absorption.
Flexibility is very important for certain internal components of pumps, especially pistons and valves, where dimensional stability is important because of tolerance requirements, yet where the component must have some degree of flexibility to function effectively. Components of this type currently in use may not have adequate flexibility and, significantly, may tend to adsorb the product and swell, so that they exceed their dimensional tolerance limits. The result is that the pump ceases to function, or functions poorly, when this occurs.
Another important disadvantage of current pump component materials is the absorption and/or permeation of flavorants from the toothpaste or other products for internal ingestion, such as food products like cheese. It should be noted at this juncture for clarity, that permeation is a process in which gases and vapors pass directly through a material. This occurs in essentially three steps: (1) adsorption and solution of the penetrant, e.g., flavor oil used in toothpaste into the polymer of the component or body part; (2) diffusion through the polymer; and (3) desorption of the penetrant to the atmosphere from outer surface of the polymer.
Thus, in the case of certain toothpaste pumps, the toothpaste contains flavorants, usually in oil form, such as peppermint. These oils undergo permeation through components exposed to the atmosphere, e.g., through the piston of the pump--which usually is PE and allows the permeation to occur, with the result that the oils flow out of the toothpaste, leaving the latter without the desired flavor.
In the case of toothpaste, the flavor of the paste or gel is an extremely important factor in consumer preference.
It has been discovered that flavor absorption by current pump component materials increases with temperature. Thus, when pumps are shipped into warm climates and especially tropical areas, the absorption of the flavorants by the pump components becomes so severe that the paste or gel loses or undergoes diminished taste character, which, as noted, is an important inducement for consumers to purchase the brand. In turn, this creates brand dissatisfaction and a consequential loss of customers.
A person not familiar with the art might believe that the flavor loss problem could be easily resolved simply by designing different paste and gel formulations for use in different climatic areas, e.g., by adding extra flavorants for tropical climates. However, this is impractical to accomplish.
Accordingly, it is an important object of this invention to provide materials for dispensing devices, such as pumps, for toothpaste and gels, and which could also be used for food products, which materials have the dual properties of superior flexibility and which also have low flavor absorption.
It is a further object of the invention to provide such materials which can also be easily molded and otherwise formed during manufacture to the rigid tolerance levels required.
It is another object that such materials be inexpensive and available in commercial quantities.
These objects and further objects and advantages of this invention will become apparent from the following detailed description of the invention and from the claims.

THE DRAWINGS

Figure 1 is a perspective view of the upper end of a dispenser to which this invention can be applied, said drawing being that of Figure 1 of U.S. Patent 4,437,591.
Figure 2 is a perspective view of the rod and rocking lever assembly of the '591 Patent.
Figure 3 is a broken longitudinal section through the complete dispenser of Figure 1, with the dispensing mechanism located in its rest position.
Figure 4 corresponds to Figure 1 of U. S. Patent 4,474,313 showing a side view of a rodless-pump type dispenser.
Figure 5 is a view corresponding to Figure 2 of the '313 Patent, showing the base of the dispenser.
Figure 6 is a longitudinal sectional view of the dispenser of Figure 4, corresponding to Figure 3 of the '313 Patent.

DETAILED DESCRIPTION

As explained above, this invention relates to the discovery of a new class of materials for dispensing devices for foods, toothpastes and gels, especially pumps for toothpastes and gels of the hand-held type.
As indicated, and as will be evident, this invention may be used in connection with a wide variety of existing and future pumps, and especially to form internal components thereof, such as valves and pistons, which must have flexibility and which tend to absorb flavor and swell up beyond tolerance limits when made of prior art materials.
In order to illustrate the usefulness of the invention, Figures 1-3 illustrate a rod-type pump from the '591 Patent and Figures 1-6 illustrate a rodless pump from the '313 patent. The illustrations should not be considered limiting, but are for example only, and the invention may be applied to other pumps and dispensers.
Turning to Figures 1-3, it is not necessary to specify each component or the detailed mode of operation, as the same are set forth in that Patent and are incorporated herein by reference. Suffice it to say that the actuator 9 pulls rod pulls rod 2 toward the top of the pump and rod 2, in turn, pulls up piston 3, thereby extruding paste through orifice 4′. The piston 3 has a sealing lip 16 which, in practise, is usually flexible.
Flavor loss occurs in commercial pumps like that shown in the '591 patent primarily through the piston 3 and sealing lip 16 which are typically made of PE or PP. As will be indicated such "internal components" made of such materials permit permeation of flavor oils, so that the important taste of the toothpaste (or other contents) is dissipated, thereby diminishing the marketability of the product.
Figures 4-6 illustrate a rodless pump and correspond to the drawing of U.S. Patent 4,474,313. Again, the specific description of all of the components shown need not be repeated here in detail and the same are incorporated from the '313 patent by reference. For present purposes, it is to be noted that this patent shows a pump which operates without a pull up rod and, rather, uses a flexible bellows B at its top which is pushed down into the pump body by pressure on part 5′ of the bellows. In turn, the physical force of the bellows--which is of flexible material--pushed paste M out of the orifice of nozzle 7′ because the pump is filled with paste M from the top of the bellows throughout the interior of the pump to the top of the piston 2. The latter moves up under pressure due to the vacuum created when the bellows B is pushed and paste M is extruded from the interior of the pump.
In the case of the device of Figures 4-6, flavor loss can occur through the piston--as in the case of the '591 patent--and also through the flexible bellows head B.
For purposes of definition, it is possible to use the invention to fabricate basic internal components such as pistons, and even, if desired, valves, acuator mechanisms and the like, all of which are referred to as "internal components". In addition, as well exemplified by the device of the '313 Patent, the head--and particularly bellows-type heads which are flexible materials--may be fabricated from materials of this invention. The head, as well as the pump body, top and bottom closures, are hereinafter referred to as the "body components".
Thus, it has been discovered by testing a number of elastomeric materials, that the terpolymer of ethylene, propylene and diene sold by Monsanto under the Trademark "Santoprene" exhibits very superior flexibility and low flavor absorption properties compared with other elastomeric materials, and over prior art materials, such as PP, PET and PE. It is believed that other such terpolymers will offer similiarly superior properties as that sold under the "Santoprene" Trademark, including terpolymers wherein the diene component is butadiene, pentadiene, etc.
Two previous U.S. Patents have been located which broadly refer to the use of elastomers. Thus, 3,255,935 discloses an "elastomeric" head 12a in Figure 1, but the specific elastomer is not disclosed and the "head" is simply a deformable cover for the pump top used to depress the piston rod. Patent 3,940,029 refers vaguely to the use of elastomeric materials in column 4, but, again, there is no identification of which elastomer of the large group of materials so classified are suggested for use. Hence, neither of these patents touches or suggests the use of the terpolymers of the present invention.
Various known elastomeric materials were tested during the discovery of the present invention. As will be indicated by the test results below, Santoprene components exhibit superior flexibility and low flavor absorption. In addition, components tested exhibited less swelling than other elastomers when in contact with flavored products, which is very important in maintaining dimensional stability of internal components, especially valves and pistons. Moreover, the low degree of flavor loss is of great advantage and applied not only to internal components, but also to body components. In particular, the flavor loss which can be expected using prior art materials to fabricate the bellows of pumps like that shown in the '313 Patent should be substantially reduced using the materials of the present invention.
As indicated, in order to determine the quantative advantages of this invention over other elastomeric materials, certain tests were performed as follows.

TEST RESULTS

Elastomer discs were fabricated from the following elastomeric materials:
Kraton G 2705 (TP Rubber)
Kraton G 2706 (Softer Rubber)
Monsanto Santoprene 201-80
DuPont Hytrel 4056 (Polyester)
Upjohn 2103 (Urethane)
Ferro TP Rubber F00000-100
The foregoing discs were immersed in a commercial toothpaste peppermint oil flavorant for two weeks to determine weight gain (which directly indicates absorption of the flavorant) and swelling. The results are set forth in Tables A and B below. It is anticipated that similar results would be achieved using other known essential oils used as flavorants, such as those disclosed in U.S. Patent 4,528,181, such as peppermint, clove, wintergreen and like oils.
From the foregoing, it will be observed that Santoprene is clearly superior to the other elastomeric materials tested in terms of low weight gain, i.e., it absorbs far less flavorant than such other materials.
Similarly, the swelling results show Santoprene to swell far less than the other materials tested, especially when diameter and height results are combined.
Futher, certain of the other materials tested are clearly not suitable for devices of this type. Thus, Kraton G2706 dissolved after 5 days and the Upjohn Urethane (results not given above) had very large swelling even after 5 days. Santoprene did undergo slight weight loss accompanied by a corresponding loss in color over time.
Another test with the same flavorant oil to determine weight gain over a one week period was conducted with the following results:
The foregoing test results show a surprising discovery, namely, that materials such as Santoprene type terpolymers of ethylene, propylene and diene --are remarkably superior to other elastomeric materials which might be considered for purposes of fabricating valves, pistons and other internal pump components as well as body components--especially bellows type head members--wherein low flavor absorption, flexibility and low swelling are important factors.
Thus, by using the materials of this invention, it is possible to fabricate pumps for dispensing toothpastes and gels, as well as foods, which will preserve such products from flavor loss in all climates, while at the same time having excellent flexibility, low swelling and other necessary properties for such pumps.

Claims

1. A device for dispensing flavored products having at least one component comprising a terpolymer of ethylene, propylene and diene

2. The invention of claim 1 wherein the device is a hand-held pump.

3. The invention of claim 2 wherein the device contains toothpaste in paste or gel form and includes one or more essential oils as a flavorant.

4. The device of claim 1 wherein the same comprises a pump having internal components and body components, and at least one of said components comprises said terpolymer.

5. The invention of claim 1 wherein said terpolymer is Santoprene.

6. A device for dispensing products containing flavor oils selected from the group consisting of pepperminent, cloves, wintergreen, spearmint and the like, wherein said device has external body components and internal components, and one or more or said external or internal components contains a terpolymer of ethylene, propylene and diene.

7. The invention of claim 6 wherein the device is a pump.

8. The invention of claim 6 wherein the pump contains toothpaste or toothpaste gels.

9. The invention of claim 6 wherein the pump contains a food product.