Methods of overmolding softer material with harder material and moisture tight container assemblies made by the methods
11331836 · 2022-05-17
Assignee
Inventors
- Donald Huber (Auburn, AL, US)
- Jonathan R. Freedman (Auburn, AL)
- Brian Tifft (Auburn, AL, US)
- Franklin Lee Lucas, JR. (Opelika, AL, US)
Cpc classification
B29C45/0003
PERFORMING OPERATIONS; TRANSPORTING
B29C45/0046
PERFORMING OPERATIONS; TRANSPORTING
B65D43/162
PERFORMING OPERATIONS; TRANSPORTING
B29L2031/712
PERFORMING OPERATIONS; TRANSPORTING
B29C45/0001
PERFORMING OPERATIONS; TRANSPORTING
B29C45/1676
PERFORMING OPERATIONS; TRANSPORTING
B29C2045/1678
PERFORMING OPERATIONS; TRANSPORTING
B29K2023/00
PERFORMING OPERATIONS; TRANSPORTING
B29C45/0081
PERFORMING OPERATIONS; TRANSPORTING
B29C45/0017
PERFORMING OPERATIONS; TRANSPORTING
B29C2045/0089
PERFORMING OPERATIONS; TRANSPORTING
B65D2543/00537
PERFORMING OPERATIONS; TRANSPORTING
International classification
B29C45/16
PERFORMING OPERATIONS; TRANSPORTING
B65D43/16
PERFORMING OPERATIONS; TRANSPORTING
B29C45/00
PERFORMING OPERATIONS; TRANSPORTING
Abstract
A method of over-molding materials includes: providing a first material in a groove in a first portion of a mold such that only a single surface of the first material is exposed to a vacant portion of the mold; providing, via an injection molding process, a second material in a liquid form in the vacant portion of the mold adjacent to, and in engagement with, the first material; and allowing the second material to solidify and become directly coupled to the first material, thus forming a single component. The second material has one or both of a greater hardness when solidified than the first material and/or a higher melting temperature than the first material.
Claims
1. A method of over-molding materials, the method comprising: providing a first material in a groove in a first portion of a mold such that only a single surface of the first material is exposed to a vacant portion of the mold; providing, via an injection molding process, a second material in a liquid form in the vacant portion of the mold adjacent to the single surface of the first material, wherein the second material flows parallel to the single surface of the first material as the second material engages the single surface of the first material; and allowing the second material to solidify and become directly coupled to the first material thus forming a single component, wherein the second material has one or both of: a greater hardness when solidified than the first material or a higher melting temperature than the first material.
2. The method of claim 1, wherein providing a first material in a groove comprises providing the first material in the groove via another injection molding process.
3. The method of claim 1, further comprising removing the component from the mold.
4. The method of claim 1, wherein the first material is an elastomeric material that is injected in liquid form into the groove in the first portion of the mold.
5. The method of claim 4, wherein the second material is a polyolefin, which has a greater hardness when solidified than the first material.
6. A method of forming a cap assembly for use with a container in forming a container assembly, the cap assembly including a seal formed from a first material and a cap formed from a second material having one or both of a greater hardness when solidified than the first material or a higher melting temperature than the first material, the method comprising: providing, in a mold having a portion which defines the shape of the cap assembly, the first material in a groove in a first portion of the mold such that only a single surface of the first material is exposed to a vacant portion of the mold; providing, via an injection molding process, a second material in a liquid form in the vacant portion of the mold adjacent to the single surface of the first material, wherein the second material flows parallel to the single surface of the first material as the second material engages the single surface of the first material; and allowing the second material to solidify and become directly coupled to the first material, thus forming the cap assembly.
7. The method of claim 6, wherein providing a first material in a groove comprises providing the first material in the groove via another injection molding process.
8. The method of claim 6, wherein the first material is an elastomeric material that is injected in liquid form into the groove in the first portion of the mold.
9. The method of claim 8, wherein the second material is a polyolefin, which has a greater hardness when solidified than the first material.
10. The method of claim 6, further comprising removing the cap assembly from the mold.
11. The method of claim 6, wherein the mold further has a portion which defines the shape of the container; wherein the method further comprises: before providing the second material in the portion of the mold which defines the shape of the cap, providing, via the injection molding process, the second material in the liquid form in the portion of the mold which defines the shape of the container; and wherein allowing the second material to solidify and become directly coupled to the first material thus forming the cap assembly further comprises allowing the second material to solidify, thus forming a container assembly in which the container is formed integrally with the cap.
12. The method of claim 11, further comprising removing the container assembly from the mold.
13. A moisture tight, resealable container assembly comprising: a container coupled to a cap assembly, the cap assembly being formed in accordance with the method of claim 6.
14. The moisture tight, resealable container assembly of claim 13, wherein the container comprises an upper portion having an opening leading to an internal cavity, the upper portion comprising a rim projecting radially outwardly.
15. The moisture tight, resealable container assembly of claim 14, wherein the cap assembly has a base and a skirt extending perpendicularly from the base around the outer periphery of the base, the cap assembly being coupled to the container by a hinge.
16. The moisture tight, resealable container assembly of claim 15, further comprising a recess formed in an inner wall of the skirt, wherein when the container assembly is in a closed position, the skirt overlies the container and the rim is situated within the recess of the inner wall of the skirt to provide a snap-fit closure arrangement between the cap assembly and the container.
17. The moisture tight, resealable container assembly of claim 16, wherein when the container assembly is in the closed position, a soft sealing arrangement is created between the upper portion of the container and the seal of the cap assembly.
18. The moisture tight, resealable container assembly of claim 17, wherein the seal is in the form of a ring, and wherein when the container assembly is in the closed position, the soft sealing arrangement is formed by vertical compression of the ring, which causes a portion of the ring to elastically expand radially into a void provided between the container and the cap.
19. The method of claim 6, wherein, the second material is injected into the mold via a port located near a portion of the mold that corresponds to a base of the container; and wherein the container and the cap assembly are integrally formed.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The invention will be described in conjunction with the following drawings in which like reference numerals designate like elements and wherein:
(2)
(3)
(4)
(5)
(6)
(7)
(8)
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
(9) As used herein, the singular form of “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise.
(10) As used herein, “and/or” means that either or both of the items separated by such terminology are involved. For example, the phrase “A and/or B” would mean A alone, B alone, or both A and B.
(11) As used herein, the statement that two or more parts or components are “coupled” shall mean that the parts are joined or operate together either directly or indirectly, i.e., through one or more intermediate parts or components, so long as a link occurs.
(12) As used herein, “directly coupled” means that two elements are directly in contact with each other. As used herein, “fixedly coupled” or “fixed” means that two components are coupled so as to move as one while maintaining a constant orientation relative to each other.
(13) As used herein, “about” in a phrase such as “disposed about [an element, point or axis]” or “extend about [an element, point or axis]” or “[X] degrees about an [an element, point or axis],” means encircle, extend around, or measured around. When used in reference to a measurement or in a similar manner, “about” means “approximately,” i.e., in an approximate range relevant to the measurement as would be understood by one of ordinary skill in the art.
(14) As used herein, “generally” means “in a general manner” relevant to the term being modified as would be understood by one of ordinary skill in the art.
(15) As used herein, the word “unitary” means a component is created as a single piece or unit. That is, a component that includes pieces that are created separately and then coupled together as a unit is not a “unitary” component or body.
(16) As used herein, the statement that two or more parts or components “engage” one another shall mean that the parts exert a force against one another either directly or through one or more intermediate parts or components.
(17) As used herein, the term “number” shall mean one or an integer greater than one (i.e., a plurality).
(18) As used herein, the phrases “sealingly engage” or “sealing engagement” shall refer to elements which contact each other in a manner such that a generally moisture-tight seal is formed therebetween.
(19) Directional phrases used herein, such as, for example and without limitation, top, bottom, left, right, upper, lower, front, back, and derivatives thereof, relate to the orientation of the elements shown in the drawings and are not limiting upon the claims unless expressly recited therein.
(20) Generally speaking, as used herein, the term “moisture-tight” is defined as having a moisture ingress (after three days) of less than 1500 μg of water, in another embodiment, less than 500 μg of water, in a further embodiment, less than 300 μg of water, in yet another embodiment, less than 150 μg of water, as determined by the following test method: (a) place one gram plus or minus 0.25 grams of molecular sieve in the container and record the weight; (b) fully close the container; (c) place the closed container in an environmental chamber at conditions of 80% relative humidity and 72° F.; (d) after one day, weigh the container containing the molecular sieve; (e) after four days, weigh the container containing the molecular sieve; and (f) subtract the first day sample from the fourth day sample to calculate the moisture ingress of the container in units of micrograms of water. A preferred rate of ingress of moisture into a moisture-tight sealed container produced according to an aspect of the disclosed concept is in the range of about 200-300 μg/day of water or less. A “moisture tight” seal therefore is a sealing engagement that alone, or in combination with additional sealing engagements, help to render a container “moisture tight” per the above definition.
(21) As used herein, the term “resealable” means the lid of the container can be opened or reopened and closed or reclosed many times (e.g. more than 10 times) and still retain its moisture-tight properties.
(22) Referring now to
(23) Continuing to refer to
(24) Container 12, cap 30 and hinge 40 may be made primarily from one or more injection moldable thermoplastic materials, including, for example, a polyolefin such as polypropylene or polyethylene. According to an optional embodiment, the container assembly 10 may be made from a mixture comprising primarily thermoplastic material and a very small proportion of thermoplastic elastomer material (wherein the final hardened product is essentially hard or incompressible). Optionally, a polymer construction of the container assembly 10 (other than seal 50, discussed below) may have up to 2% TPE by weight.
(25) In order to provide for an improved moisture tight seal between cap 30 and container 12, cap assembly 29 further includes a compressible seal 50 which is of similar shape as upper portion 20 of container 12 and cap 30 and which is formed from a softer material and/or a material having a lower melting point (e.g., a thermoplastic elastomer) than the material from which container 12 and cap 30 is formed. As used herein, the terms “elastomer” or “elastomeric material” are to be understood in a broad sense. A particularly preferred elastomer for seal 50 is a thermoplastic elastomer (TPE), optionally one having a Shore A hardness of from 20 to 50, preferably from 20 to 40, more preferably from 20 to 35. Alternatively, the terms “elastomer” or “elastomeric material” may include silicone rubbers or other preferably injection moldable soft and resilient materials appropriate for creating a compression seal against a comparatively harder (e.g., thermoplastic) surface. Formation of seal 50 is discussed in detail below.
(26)
(27) In order to provide such improved moisture tight sealing, the interacting surfaces of the hard sealing arrangement, i.e., the surfaces of rim 24 of container 12 and recess 36 of lid 30, must be free from scratches and parting lines or else moisture can easily transfer past such hard seal. As a result of such requirement, seal 50 cannot be over-molded onto base 32 of cap 30, as removal of the core needed to form cap 30 and reinsertion of the other core needed to form seal 50 may result in scratching/scarring of the surface of recess 36, thus creating a point for moisture ingress. In order to avoid such scratching/scarring of the surface of recess 36 of cap 30, cap 30 is instead uniquely over-molded onto seal 50, an example of which is described below in conjunction with
(28) Referring now to
(29) It is to be appreciated that conventional practice in injection molding is to mold a softer material onto a harder material as otherwise the harder material will tend to force the softer material out of the mold. However, according to the unique disclosed concept, by effectively shielding the softer material of seal 50 in groove 100 such that only surface 50A thereof is exposed, and then causing the supply F of harder plastic to pass generally parallel and adjacent to such surface, the harder plastic material which forms the remainder of container assembly 10 can be over-molded to seal 50, thus producing the unblemished surface of recess 36 previously discussed.
(30) As illustrated in
(31) In an exemplary embodiment of the disclosed concept, the seal 50 has a vertical thickness of from 0.25 mm to 1.25 mm.
(32) The container assembly 10 may be generally of any desired size needed in order to house desired contents. Although shown as being integrally formed as a unitary element, it is to be appreciated that cap 30 and container 12 could also be formed as separate elements and then assembled together, as long as cap 30 and seal 50 are otherwise formed generally as described herein.
(33) An optional feature of the disclosed concept is now discussed. Referring to
(34)
(35)
(36) Notably, the seal 50 (e.g., in the form of a ring) is not bounded or blocked by any structure on either an immediate right side 50R or left side 50L thereof. As such, when the seal 50 is compressed vertically, a portion thereof elastically expands or migrates radially outward (towards the left), inward (towards the right) or both. A void 280 is provided, e.g., between the seal 50 and the skirt 34 of the lid 30 to provide “living space” for the seal material to radially expand when engaged.
(37) First, it results in tempering the vertical spring force between the elastomer and the rim. While it is desired that some slight spring force is provided to strengthen or reinforce the sealing engagement 264, excessive spring force may tend to reduce the opening force to an extent that the container may inadvertently pop open. A balance must be struck between a desirably low opening force on the one hand (especially for elderly and/or diabetic users) and an opening force that is so low that it can result in inadvertent container openings, e.g., via common pressure variations that may occur within the container during transport. When the soft material (e.g., elastomer) of seal 50 is permitted to expand radially, the vertical spring force may thus be provided at an acceptable level.
(38) The second important function is that the surface area of contact between the respective sealing surfaces of the sealing engagement 264 increases via radial expansion of the relatively soft material of the seal 50. This increase of the soft-to-hard (e.g., elastomer-to-thermoplastic) sealing surface area provides a more robust seal at the site of seal engagement 264.
(39) In the molding art, methods according to optional aspects of the disclosed concept enable one to provide the seal 50 without it being bounded, blocked or reinforced on either an immediate right side 50R or left side 50L thereof, e.g., by a thermoplastic extension on the lid 30 or other structure.
(40) Optionally, a container assembly according to any embodiment of the disclosed concept may be advantageously used to house diagnostic test strips, drug delivery strips, biologic compositions, supplements, pharmaceuticals or any other product sensitive to moisture. Optionally, a container assembly according to any embodiment may include therein a desiccant material (e.g., in the form of a desiccant entrained polymer, preferably a three-phase desiccant entrained polymer) to absorb moisture in the internal cavity. The term “three phase polymer” refers to a desiccant entrained polymer comprising a base polymer, desiccant and channeling agent, e.g., as described in U.S. Pat. Nos. 5,911,937, 6,080,350, 6,124,006, 6,130,263, 6,194,079, 6,214,255, 6,486,231, 7,005,459, and U.S. Pat. Pub. No. 2016/0039955, each of which is incorporated herein by reference as if fully set forth. Advantageously, in an optional aspect of the invention, the soft-to-hard seal in combination with the hard-to-hard seal (in series) reliably reduces moisture ingress. This, in turn, permits reduced use of such desiccant material, resulting in lower manufacturing costs. Optionally, a desiccant entrained polymer insert may be assembled to or co-molded with the container.
EXAMPLES
(41) The invention will be illustrated in more detail with reference to the following Examples, but it should be understood that the present invention is not deemed to be limited thereto.
Example 1
(42) Tests were run to measure moisture ingress of 24 ml vials according to the container embodiment shown in
(43) TABLE-US-00001 Mean Standard Group Ingress (μg/day) Deviation (μg/day) Sample Size A 399.8 22.61 48 B 440.9 105.5 7553
(44) As the data show, the addition of the second seal resulted in a meaningful reduction of the mean ingress and a surprisingly significant reduction in the standard deviation of moisture ingress. This significant reduction in standard deviation is notable and important from a production standpoint. Essentially, the soft seal in combination with the hard seal allows for a much more controlled and predictable (i.e., lower variation) in moisture ingress so that container moisture budgets can be much more precisely met. This allows for a reduction in desiccant material necessary per vial and hence a reduction in production costs associated with the reduced amount of desiccant material.
Example 2
(45) Tests were run to measure moisture ingress of 17 ml vials according to the container embodiment shown in
(46) TABLE-US-00002 Mean Standard Group Ingress (μg/day) Deviation (μg/day) Sample Size A′ 305.4 20.54 144 B′ 420.7 76.91 2923
(47) As with Example 1, the data show that addition of the soft seal to assemblies having the hard seal resulted in a meaningful reduction of the mean ingress and a surprisingly significant reduction in the standard deviation of moisture ingress.
(48) It should be noted that nominal volumetric measurements with reference to diagnostic test strip vials are approximate and generally understood in the industry. For example, a “17 mL” vial may vary slightly from that precise volumetric measurement as may a “24 mL” vial. These vial volumes are well understood in the industry. To address this issue, for some embodiments, a volumetric range is provided, e.g., a container having an internal volume of 12 mL to 30 mL.
(49) Although the invention has been described in detail for the purpose of illustration based on what is currently considered to be the most practical and preferred embodiments, it is to be understood that such detail is solely for that purpose and that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of the appended claims. For example, it is to be understood that the present invention contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.
(50) In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word “comprising” or “including” does not exclude the presence of elements or steps other than those listed in a claim. In a device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The word “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. In any device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain elements are recited in mutually different dependent claims does not indicate that these elements cannot be used in combination.