Anti-rollback resealing adhesive

Abstract

Adhesive compositions are described that replace washers and liners in sealing applications for manually detachable packages. The adhesive composition is particularly useful for preventing leakage and spill of its packaged contents during storage and transportation.

Description

[0001] This application is a divisional application of Chinese patent application No. 202080006138.6 (the international application number of which is PCT / US2020 / 024966), whose invention name is “Anti-rollback Resealable Adhesive” and whose application date is March 26, 2020, and all the contents of which are incorporated herein by reference. Technical Field

[0002] The present invention relates to adhesive compositions that replace gaskets and liners in manually removable sealed container closures. The adhesive compositions of the present invention are particularly useful for preventing back-off torque of container closures and, therefore, preventing leakage and spillage of container contents during storage and transport. Background Art

[0003] Threadlocking adhesives are commonly used to prevent back-off torque and to adhesively bond and interlock engageable structural fasteners into their final state. These threadlocking adhesives have such strong bonds that they cannot be separated by hand. Low-force threadlocking adhesives can also be used, but once the bond is broken, the adhesive no longer has any cohesive force and will no longer interlock.

[0004] With the rise of e-commerce, the delivery of liquid and gel products to consumers is also on the rise. Containers and packaging for liquid and / or gel products must be leak-proof and provide safe delivery of the products.

[0005] Containers are sealed to prevent loss of their contents during storage and transport. An application torque is applied to the container's closure to seal the contents; however, over time and with handling, some torque is lost, a phenomenon known as back-off. To compensate for this back-off torque, a higher initial application torque may be applied, which may damage the container, wear out the equipment, or prevent consumers from opening the container by hand alone. Additional gaskets, induction seal liners, internal seals, valve seals, or liners are often applied to the container to prevent leaks; or additional plastic liners or foam bag liners are added to the container, which increases the cost, complexity, and carbon footprint of the product. In addition, these additional seals add more steps to the packaging process, requiring several retoolings of the production line (and several shipments to and from the production line), further increasing the carbon footprint.

[0006] There is an ongoing need for a more sustainable solution that minimizes carbon footprint, cost, and complexity while maintaining the seal of the container and packaging during shipping and even after the container is opened. The present invention addresses this need in the art. Summary of the Invention

[0007] The present invention provides an alternative to, or in addition to, tapes, gaskets, liners or induction seals in containers and packaging.

[0008] One aspect of the present invention relates to an article comprising a first threaded member having threads partially coated with a resealable adhesive. The resealable adhesive is a water-based adhesive.

[0009] Another aspect of the present invention provides an article comprising the first threaded member described above and a second threaded member cooperatively engaged with the first threaded member, whereby a resealable adhesive is applied between the first threaded member and the second threaded member. The resealable adhesive is a water-based adhesive characterized by having (1) a removal torque of about 4 to about 20 in-lb measured according to ASTM D2063; and (2) a resealability torque of about 2 to about 15 in-lb measured according to ASTM D2063.

[0010] In another aspect, the present invention provides an article comprising a non-threaded closure member having a circumference or perimeter dimension and a height dimension. The closure member is at least partially coated with a resealable adhesive comprising a water-based adhesive.

[0011] In yet another aspect, the present invention provides an article comprising the non-threaded closure member described above and a second non-threaded member matingly engaged with the first non-threaded member, whereby a resealable adhesive is applied between the first and second non-threaded members. The resealable adhesive is a water-based adhesive characterized by having (1) a removal torque of about 4 to about 20 in-lbs as measured according to ASTM D2063; and (2) a resealable torque of about 2 to about 15 in-lbs as measured according to ASTM D2063.

[0012] Yet another aspect of the present invention provides a method for sealing a threaded component, the method comprising:

[0013] (a) providing a first threaded member;

[0014] (b) providing a second threaded member cooperatively engageable with the first threaded member;

[0015] wherein at least one of the first threaded member and the second threaded member is at least partially coated with a resealable coating composition; and

[0016] (c) fittingly engaging the first threaded member and the second threaded member.

[0017] The resealable coating composition substantially fills the mating engagement space between the first threaded member and the second threaded member. The resealable coating composition is a water-based adhesive characterized by having (1) a removal torque of about 4 to about 20 in-lbs as measured according to ASTM D2063; and (2) a resealable torque of about 2 to about 15 in-lbs as measured according to ASTM D2063.

[0018] Another aspect of the present invention provides a method for sealing a non-threaded component, the method comprising:

[0019] (a) providing a first non-threaded member having a circumferential or perimeter dimension and a height dimension;

[0020] (b) providing a second non-threaded member cooperatively engageable with the first non-threaded member;

[0021] wherein at least one of the first non-threaded member and the second non-threaded member is at least partially coated with a resealable coating composition; and

[0022] (c) matingly engaging the first non-threaded member and the second non-threaded member.

[0023] The resealable coating composition substantially fills the mating engagement space between the first non-threaded member and the second non-threaded member. The resealable coating composition is a water-based adhesive characterized by having (1) a removal torque of about 4 to about 20 in-lbs as measured according to ASTM D2063; and (2) a resealable torque of about 2 to about 15 in-lbs as measured according to ASTM D2063. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a diagram of a threaded cap and a threaded neck lined with a resealable adhesive.

[0025] Figure 2 is a diagram of a non-threaded cap and a non-threaded neck lined with a resealable adhesive. DETAILED DESCRIPTION

[0026] The present invention provides a resealable adhesive-lined closure for a container that is free of additional devices designed to seal off the opening and prevent loss of its contents. The resealable adhesive-lined closure is free of gaskets, induction seal liners, internal seals, valve seals, or liners typically made of metal, plastic, foam, paper, and / or foil. The resealable adhesive-lined closure is usable with both threaded and non-threaded closures.

[0027] The term "applied torque" is the torque force measured in inch-pounds required to screw the closure onto the container.

[0028] The term "rollback" refers to the relaxation of forward thrust or loss of torque after the closure is applied. This can be affected by top load, the compressibility and resilience of the closure liner, the consistency of the applied torque, and the mechanical interaction of the closure and bottle.

[0029] The term "removal torque" is the amount of force required to loosen, open, unscrew or remove a closure from a container for the first time after closure with a specific applied torque.

[0030] The term "re-torque" is the amount of torque that is re-applied to close the container.

[0031] The term "resealable torque" is the amount of force required to re-loosen, re-open, re-unscrew or remove a closure after a re-applying torque has been applied to the closure, which measures the subsequent opening torque.

[0032] The terms "container" and "package," which are used interchangeably, are a medium that holds contents, including liquids, gels, and solids.

[0033] The present invention relates to adhesively securing a matingly engageable threaded member and its complementary threaded member such that the closure members are adhesively bonded and retain a removal torque of about 4 to about 20 in-lbs, as measured in accordance with ASTM D2063. Furthermore, the resealable adhesive provides resealability and retains a torque of about 2 to about 15 in-lbs, as measured in accordance with ASTM D2063, upon subsequent opening.

[0034] The present invention also relates to adhesively securing matingly engageable non-threaded members and their complementary non-threaded members at the same removal torque and resealability values ​​as described above.

[0035] Once the applied torque is applied to the member, the added resealable adhesive locks and seals the member. This resealable adhesive significantly increases the torque required to break or rotate the threaded and non-threaded members of the container's engagement, and provides leak resistance and spill resistance to the container without the need for additional gaskets. Typical torque values ​​of approximately 4 to approximately 20 in-lb make it possible to manually remove the connected member. Values ​​greater than approximately 20 in-lb will require additional tools to separate these members. Values ​​less than approximately 2 in-lb may rupture the seal and cause contents to leak.

[0036] The resealable adhesive of the present invention has large gap-filling capabilities, is non-messy, does not drip, can be applied to a container surface, and can be stored prior to use.

[0037] This resealable adhesive is a water-based adhesive. Usually, water-based adhesives include water-based polymers or emulsion polymers. Emulsion polymers can be present in the adhesive composition with any amount, and desirably, exist with an amount of about 50 % by weight to about 99.5 % by weight of the adhesive composition before the composition solidifies. Depends on the emulsion polymer, based on the emulsion polymer, solids content changes between about 50 % by weight to about 90 % by weight. The emulsion polymer component can include any desired polymer component, including vinyl acetate ethylene dispersion, polyvinyl acetate, polyvinyl acetate polyvinyl alcohol, dextrin-stabilized polyvinyl acetate, polyvinyl acetate copolymer, vinyl acetate ethylene copolymer, vinyl acrylic acid (acrylic), styrene acrylic acid, acrylic acid, styrene butyl rubber, polyurethane, ethylene vinyl acetate, polyacrylic acid (polyacrylic) and their mixture. Particularly preferred emulsion polymer components are polyacrylic acid, vinyl acetate ethylene dispersion, ethylene vinyl acetate and polyvinyl acetate.

[0038] It should be understood that the water-based adhesive may also contain other compatible components, additives and / or ingredients commonly found in known water-based adhesives, such as: tackifiers known in the art; wetting agents; preservatives, such as antioxidants, antimicrobial agents; fillers; pigments; dyes; stabilizers; rheology modifiers; microspheres; polyvinyl alcohol; emulsifiers; preservatives; pigments; corrosion inhibitors; water corrosion inhibitors; fillers; lubricants (such as greases, oils and waxes); defoamers; and / or coupling agents. These components may be included in an amount of about 0.05% to about 50% by weight of the adhesive composition before the composition is cured.

[0039] Exemplary water-based adhesives include pressure-sensitive adhesives, ethylene vinyl acetate-based adhesives, and polyacrylic-based adhesives.

[0040] Regardless of the specific formulation, the water-based adhesive formulation is combined with methods known in the art. The water-based adhesive is desirably formed into a paste consistent with sufficient viscosity and sag resistance so that the adhesive can be easily applied to both threaded and non-threaded surfaces of matable components without subsequent dripping, sagging, or shifting of the adhesive prior to mating and locking the complementary components.

[0041] In one embodiment, the resealable adhesive can be applied to the surface of one of the closure members. Depending on the thickness, flow characteristics, and viscosity characteristics required or present in the specific end-use application of the composition, the resealable adhesive can be applied in any suitable manner, such as by extrusion, spraying, dipping, roller coating, contact coating, or in any other suitable manner. The resealable adhesive is pre-applied in a set amount (at a coating weight in a specified area) to the surface area of ​​the member to be engaged with the complementary mating member; then, depending on the type of resealable adhesive, this pre-applied medium can be dried in any suitable manner, such as by ambient (room temperature) or by elevated temperature drying conditions effective for drying materials coated with water-based adhesives. As the water evaporates and solidifies, the adhesive is then dried and cured to a thickness lower than the applied thickness.

[0042] In another embodiment, a set amount of resealable adhesive can be pre-applied to the surface area of ​​the component to be joined with the complementary mating component, and the second component is joined before the adhesive is dried and cured. The adhesive in the joined components is then dried and cured in any suitable manner, for example, by ambient (room temperature) or by elevated temperature drying conditions effective for drying materials coated with water-based adhesives.

[0043] A uniform thickness of the resealable adhesive at the closure member is desirable; however, an uneven thickness may become more uniform under the application of force, in which case mating the two members will squeeze the resealable adhesive together to form the desired seal.

[0044] like Figure 1 As shown, a resealable adhesive (4) is applied to the threaded neck region (3). The neck member is matingly engaged to the threads (2) of the cap (1).

[0045] And if Figure 2 As shown, a resealable adhesive (30) is applied to the neck (20). The neck is fitted snugly onto the cap (10).

[0046] Once applied to one of the components, the resealable adhesive remains on the surface of the threaded or non-threaded component until mated with its complementary component. In use, the component having the pre-applied resealable adhesive is brought into contact with the mating surface of the complementary component, which preferably has the resealable adhesive previously applied to its surface, to facilitate securing the joined components. In this manner, a pressure differential is applied to the matingly engaged components.

[0047] Surprisingly, the removal torque is independent of the thickness of the resealable adhesive in the joined components, with the coating ranging from about 0.001 g / in 2 to about 1g / in 2 , preferably about 0.02 g / in 2 to about 0.5g / in 2 The resealable adhesive is self-adjusting and provides an optimal removal torque range of about 4 to about 20 in-lb when dry and cured, and a reseal torque range of 2 to about 15 in-lb. The resealable adhesive also retains about 40 to 100% of the reapplied torque, and the loss of back-off torque is not noticeable.

[0048] In some embodiments, the resealable adhesive is clear or milky white. In other embodiments, pigments are added to tint or dye the color of the resealable adhesive to match the color of the container.

[0049] In another embodiment, the present invention is a method of adhesively joining threaded or non-threaded components by the following steps:

[0050] (a) providing a first threaded or non-threaded member;

[0051] (b) providing a second threaded or non-threaded member cooperatively engageable with the first member;

[0052] wherein at least one of the first member and the second member is at least partially coated with a resealable coating composition; and

[0053] (c) fittingly engaging the first threaded member and the second threaded member.

[0054] The resealable coating composition substantially fills the mating joint space between the first component and the second component. The resealable coating composition is a water-based adhesive characterized by having (1) a removal torque of about 4 to about 20 in-lbs measured according to ASTM D2063; and (2) a reseal torque of about 2 to about 15 in-lbs measured according to ASTM D2063.

[0055] The present invention may be used instead of or in addition to bags, bands, films, strips, gaskets, liners, ropes, and various other shapes of sheets that may be applied to container closures.

[0056] Container closure components with which the present invention may be practiced include any structural element, such as a cap and closure, a screw-top cap, a snap fastener, a tongue-and-groove fastener, a hook-and-loop fastener, a press-fit element, a pump dispenser, and the like, which can be adhesively engaged with a complementary mating structure. The closure component and the complementary component can thus include a cap and closure assembly that are threadedly or non-threadedly engaged and have a resealable adhesive that fills the gap between the matingly engaged components.

[0057] The present invention can be used as caps, lids and closures and can be formed into container (bottle) necks, screw caps, roll on tamper-evident closures, safety closures, dispensing and dosing closures, trigger spray closures, safety closures, valve closures, tube caps, tamper-evident closures, sports caps, snap-on hinge caps, screw caps, push-pull closures, pours and dropper closures, child-resistant closures, etc.

[0058] Such caps and closures are typically made from polypropylene, polyethylene, high-density polyethylene, low-density polyethylene, polyvinyl chloride, and / or polyethylene terephthalate.

[0059] Example

[0060] All torque values ​​were measured according to ASTM D2063 using a Mark 10 MTT 01-50.

[0061] Example 1

[0062] A sample polyacrylic-based pressure sensitive adhesive having a solids content of about 66%, a viscosity of 900-1000 cP, and a pH of 4.5 was used as the resealable adhesive.

[0063] Various coat weights (in grams per square inch) of sample adhesive were applied to a first threaded member and then dried and cured.

[0064] At least three threaded components were conditioned at room temperature (21-25°C) for 24 hours and each component was screwed into its matable second threaded component by hand (applying force). The mated components were then tested for removal torque and recorded in Table 1.

[0065] Once removed, each component was resealed with the specified reapply torque and tested for reseal torque. The reseal torque values ​​and retention torque percentages are also listed in Table 1.

[0066] Table 1.

[0067]

[0068] The coating weights of the first three samples allowed for removal and reseal torques within the hand-openable range. These examples demonstrate that when the adhesive is water-based, the removal and reseal torque values ​​are somewhat independent of coating weight. Furthermore, the resealable adhesive retained greater than approximately 42% of its torque.

[0069] Example 2

[0070] The corresponding torque values ​​of various coating weights of hot melt adhesive [ethylene vinyl acetate polymer (30 wt. %), tackifier (60%), wax (8%) and additives (2%)] were tested and the results are shown in Table 2.

[0071] Table 2.

[0072]

[0073] As demonstrated above, the coating weight of hot melt adhesive directly affects the removal torque. Unlike water-based adhesives, the coating weight of hot melt adhesives at 0.268 g / in 2 Applying a hot melt adhesive at a coat weight of 1000 Nm will increase the removal torque beyond the hand-opening range.

[0074] It is obvious to those skilled in the art that many modifications and variations can be made to the present invention without departing from the spirit and scope of the present invention. The specific embodiments described herein are provided by way of example only, and the present invention is limited only by the terms of the appended claims and the full scope of equivalents to which these claims are entitled.

Claims

1. An article comprising a first threaded member, wherein the threads of the first threaded member are at least partially coated with a resealable adhesive comprising a water-based adhesive, wherein the coating weight of the resealable adhesive is 0.02 g / in 2 Up to 0.5g / in 2 ,and The water-based adhesive comprises a polyacrylic acid-based pressure-sensitive adhesive.

2. The article of claim 1 , wherein the article further comprises a second threaded member cooperatively engaged with the first threaded member, whereby the resealable adhesive is applied between the first threaded member and the second threaded member; wherein the resealable adhesive is characterized by having a removal torque of about 4 to about 20 in-lbs as measured according to ASTM D2063; and wherein the threaded member has a resealable torque of about 2 to about 15 in-lb measured according to ASTM D2063.

3. The article of claim 2, wherein the first threaded member or the second threaded member is independently made of polypropylene, polyethylene, high-density polyethylene, low-density polyethylene, polyvinyl chloride, or polyethylene terephthalate.

4. The article of claim 1, wherein the first threaded member is a cap, lid, or closure.

5. The article of claim 1, wherein the first threaded member is a container neck or bottleneck.

6. An article comprising a non-threaded closure member having an area having a circumferential or perimeter dimension and a height dimension, wherein said area of ​​said closure member is at least partially coated with a resealable adhesive comprising a water-based adhesive, wherein the coating weight of the resealable adhesive is 0.02 g / in 2 Up to 0.5g / in 2 ,and The water-based adhesive comprises a polyacrylic acid-based pressure-sensitive adhesive.

7. The article of claim 6, wherein the article further comprises a second non-threaded member matingly engaged with a region of the first non-threaded member, whereby the resealable adhesive is applied between the first and second non-threaded members; wherein the resealable adhesive is characterized by having a removal torque of about 4 to about 20 in-lbs as measured according to ASTM D2063; and wherein the threaded member has a resealable torque of about 2 to about 15 in-lb measured according to ASTM D2063.

8. The article of claim 7, wherein the first or second non-threaded member is independently made of polypropylene, polyethylene, high-density polyethylene, low-density polyethylene, polyvinyl chloride, or polyethylene terephthalate.

9. The article of claim 7, wherein the first non-threaded member is a cap, lid, or closure.

10. The article of claim 7, wherein the first non-threaded member is a container neck or bottleneck.

11. A method of sealing a component, comprising: (a) providing a first component; (b) providing a second member cooperatively engageable with the first member; wherein at least one of the first member and the second member is at least partially coated with a resealable coating composition; (c) matingly engaging the first member with the second member; whereby the resealable coating composition substantially fills the mating engagement space between the first and second components; wherein the resealable adhesive is a water-based adhesive characterized by having a removal torque of about 4 to about 20 in-lbs as measured according to ASTM D2063; wherein the resealable adhesive has a resealable torque of about 2 to about 15 in-lbs measured according to ASTM D2063, wherein the coating weight of the resealable adhesive is 0.02 g / in 2 Up to 0.5g / in 2 ,and The water-based adhesive comprises a polyacrylic acid-based pressure-sensitive adhesive. 12 . The method of sealing a member according to claim 11 , wherein the first member or the second member is independently made of polypropylene, polyethylene, high-density polyethylene, low-density polyethylene, polyvinyl chloride, or polyethylene terephthalate.

13. The method of sealing a component according to claim 11, wherein at least one of the first component and the second component is a cap, a cover, or a closure.

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