PVC-free container cover and manufacturing method thereof

Abstract

A container lid for use with a container adapted to store food or beverage, the container lid comprising: a lid body configured for attachment to a neck of the container; and a gasket attached to the cap body, the gasket configured for deformation and compression between the cap body and the container, where the gasket is made of a sealing material comprising at least 50% by weight of a polyurethane elastomer; wherein the polyurethane elastomer is the reaction product of an isocyanate component and a curing agent component having a hydroxyl number (OH) greater than 350.

Description

Technical Field

[0001] Embodiments of the present disclosure relate generally to a PVC-free container closure and method of making the same, and more particularly, to a PVC-free container closure including a gasket formed of a polyurethane elastomer. Background Art

[0002] Polyvinyl chloride (PVC) has been widely used in food packaging applications, and in particular, they have been used as sealing materials such as in container lids. However, the manufacture, use and disposal of PVC can cause harm to the environment and human health. In addition, the presence of PVC in the packaging has brought compatibility issues, making it impossible to easily recycle plastic waste containing PVC and other plastic materials. In addition, PVC-based materials often need to use plasticizers, such as epoxidized soybean oil, which may potentially migrate to the food packaged in the container, thereby contaminating the food.

[0003] On the other hand, PVC materials have the processing and performance characteristics required in container lids. Container lids are often used with containers made of glass or plastic to store food and / or beverages. Depending on the use environment, container lids may have different degrees of properties. For example, under corrosive conditions, the container lid must not be affected by corrosive materials, but still have enough elasticity to form a seal. In the case where the container lid is used as a bottle cap closure and the closure is applied and removed (and / or resealed), it is expected that the container lid maintains its integrity and is not torn or torn so that its fragments contaminate food or beverages. In addition, the container lid should not lose its sealing integrity because of deformation. Depending on the type of food and / or liquid content, the filling temperature may be lower or higher than room temperature (e.g., sterilization), thereby proposing even higher requirements for the container lid.

[0004] Thus, there remains a need for a PVC-free container closure for use in food and beverage packaging that provides similar or improved processing and / or performance properties as container closures made from PVC. Summary of the invention

[0005] A container cap is disclosed in the embodiments of this invention. The container cap is used for use with a container suitable for storing food or beverages, and the container cap comprises: a cap body, the cap body being configured to be attached to the neck of the container; and a gasket attached to the cap body, the gasket being configured to be deformed and compressed between the cap body and the container, wherein the gasket is made of a sealing material comprising at least 50% by weight of a polyurethane elastomer; wherein the polyurethane elastomer is a reaction product of an isocyanate component and a curing agent component having a hydroxyl value (OH) greater than 350.

[0006] Also disclosed in the embodiments of the present invention is a method for manufacturing a container cap, which is suitable for use with a container for storing food or beverages. The method includes: providing a cap body, which is configured to be attached to the neck of the container; reacting an isocyanate component with a curing agent component having a hydroxyl value (OH) greater than 350 along the cap body at a temperature of 60°C to 240°C to form a polyurethane elastomer gasket, wherein the polyurethane elastomer gasket is positioned on the cap body so that the polyurethane elastomer gasket can be deformed and compressed when the cap body is attached to the container, and wherein the polyurethane elastomer gasket and the cap body together form a container cap.

[0007] In one or more embodiments herein, the container lid is a lug screw cap, a Press-on Twist-Off® cap, a capped closure, a crimped cap or a disposable cap, or a metal cap that can be rolled onto the container.

[0008] In one or more embodiments herein, the sealing material is substantially free of components that are liquid at room temperature.

[0009] In one or more embodiments herein, the polyurethane elastomeric gasket is substantially free of polyvinyl chloride.

[0010] In one or more embodiments herein, the sealing material has a Shore A hardness of 50 to 95.

[0011] In one or more embodiments herein, the isocyanate component comprises: i. a polyisocyanate, which is an aliphatic isocyanate or an alicyclic isocyanate; and ii. an isocyanate-reactive component.

[0012] In one or more embodiments herein, the polyisocyanate is selected from hexamethylene diisocyanate ("HDI") and its isomers, isophorone diisocyanate ("IPDI") and its isomers, norbornane diisocyanate ("NBDI") and its isomers, tetramethylxylene diisocyanate ("TMXDI") and its isomers, and xylene diisocyanate ("XDI") and its isomers, and mixtures thereof.

[0013] In one or more embodiments herein, the isocyanate reactive component is selected from the group consisting of polyether polyols, polyester polyols, polycaprolactone polyols, polycarbonate polyols, hydroxyl terminated polybutadiene polyols, natural oil based polyols, short chain diols and mixtures thereof.

[0014] In one or more embodiments of the present invention, the isocyanate-reactive component is a polyester polyol, which comprises: i. an acidic component, the acidic component comprising the residue of at least one dicarboxylic monomer; and ii. a diol component, the diol component comprising the residues of: (i) 2,2,4,4-tetraalkyl-1,3-cyclobutanediol (TACD); and (ii) at least one diol or polyol other than TACD, wherein the hydroxyl functionality of the polyester polyol is 2 to 3.

[0015] In one or more embodiments herein, the curing agent component comprises: i. one or more isocyanate-reactive compounds; and ii. a catalyst.

[0016] In one or more embodiments herein, the one or more isocyanate-reactive compounds are hydroxyl-terminated isocyanate-reactive compounds or amine-terminated isocyanate-reactive compounds.

[0017] In one or more embodiments herein, the hydroxyl-terminated isocyanate-reactive compound is selected from the group consisting of polyether polyols, polyester polyols, polycaprolactone polyols, polycarbonate polyols, hydroxyl-terminated polybutadiene polyols, natural oil-based polyols, short chain diols, and mixtures thereof.

[0018] In one or more embodiments herein, the one or more isocyanate-reactive compounds is 2,2,4,4-tetraalkyl-1,3-cyclobutanediol.

[0019] In one or more embodiments herein, the catalyst is selected from the group consisting of amine-based catalysts, tin-based catalysts, zinc-based catalysts, zirconium-based catalysts, bismuth-based catalysts, and mixtures thereof.

[0020] Additional features and advantages of the embodiments will be set forth in the detailed description below, and will be partially apparent to those skilled in the art from the description or recognized by practicing the embodiments described herein. It should be understood that the above and following detailed descriptions describe various embodiments and are intended to provide an overview or framework for understanding the nature and characteristics of the claimed subject matter. DETAILED DESCRIPTION

[0021] The embodiment of container lid and its manufacturing method will be referred to in detail now.Container lid can be used in the packaging of food and / or beverage.For example, container lid described herein can be used with metal or plastic container suitable for storing food and / or beverage.Container lid can be selectively coupled to container, to form fluid-tight seal between container and environment.However, it should be noted that this is merely an illustrative implementation of the embodiment disclosed herein.These embodiments are applicable to other technologies that are susceptible to problems similar to those discussed above.For example, container lid described herein can be used in other packaging applications, such as in cosmetics and medicines, all of which are within the scope of embodiments of the present invention.

[0022] In the embodiments herein, the container cover comprises a cover body and a gasket attached to the cover body. The container cover can be a lug screw cover, a Press-on Twist-Off® cover, a capped cover, a crimped cover or a disposable cover, or a metal cover that can be rolled onto the container. In some embodiments, the cover body comprises a top plate portion and a skirt portion extending vertically from the top plate portion, wherein the top plate portion and the skirt portion define a generally cylindrical inner groove. The top plate portion can generally be a circular shape. In other embodiments, the cover body comprises: a top plate portion and a skirt portion extending vertically from the top plate portion, wherein the top plate portion and the skirt portion define a generally cylindrical inner groove; and one or more lugs positioned near the edge of the skirt portion. The lug can extend radially inward from the skirt into the inner groove. The other example of suitable container lid is described in for example US 10,450,449 B2, US 10,189,610 B2 and EP 2 509 883 B1, and these documents are incorporated herein by reference.The gasket described herein is attached to the cap body and is configured to be deformed and compressed between the cap body and the container.In some embodiments, the gasket is installed to the top plate part and / or the skirt part in the inner groove of the cap body.

[0023] The gasket is made of the sealing material of the polyurethane elastomer comprising at least 50 wt %. All single values ​​and subranges are included and disclosed herein. For example, in some embodiments, the polyurethane elastomer constitutes at least 60 wt %, at least 70 wt %, at least 80 wt %, at least 90 wt %, at least 95 wt % of the sealing material. In other embodiments, the polyurethane elastomer constitutes 50 wt % to 100 wt %, 65 wt % to 100 wt %, 75 wt % to 100 wt %, 85 wt % to 100 wt %, 92 wt % to 100 wt % or 95 wt % to 100 wt % of the sealing material.

[0024] In embodiments herein, the sealing material is substantially free of (or alternatively, free of) polyvinyl chloride. As used herein, the term "substantially free of" means that polyvinyl chloride is not intentionally added to the sealing material. As used herein, the term "free of" means that the amount of polyvinyl chloride is undetectable. In one or more embodiments herein, the sealing material may be substantially free of components that are liquid at room temperature.

[0025] In one or more embodiments herein, the Shore A hardness of the sealing material may be 50 to 95. All individual values ​​and subranges are included and disclosed herein. For example, in some embodiments, the sealing material may have a Shore A hardness ranging from a lower limit of 50, 55, 60, 63, or 65 to an upper limit of 95, 90, 85, 83, or 80. The Shore A hardness can be measured at 25° C. using a Shore A hardness meter according to ASTM D-2240.

[0026] In embodiments herein, the polyurethane elastomer is the reaction product of an isocyanate component and a curing agent component having a hydroxyl value (OH) greater than 350. In one or more embodiments herein, the NCO content of the isocyanate component may be 5.0% to 25.0%. All individual values ​​and subranges are included and disclosed herein. For example, in some embodiments, the isocyanate component may have an NCO content ranging from a lower limit of 5.0%, 7.0%, 10.0% or 11.5% to an upper limit of 25.0%, 20.0%, 18.0%, 15.0% or 14.5%. The NCO content may be determined according to ASTM D2572.

[0027] In some embodiments, the isocyanate component may include: a polyisocyanate, which is an aliphatic isocyanate or an alicyclic isocyanate; and an isocyanate reactive component. As used herein, "polyisocyanate" is any compound containing two or more isocyanate groups. Examples of suitable aliphatic polyisocyanates may include aliphatic polyisocyanates having 3 to 16 carbon atoms, or alternatively 4 to 12 carbon atoms in a linear or branched alkylene residue. Examples of suitable alicyclic polyisocyanates may include alicyclic polyisocyanates having 4 to 18 carbon atoms, or alternatively 6 to 15 carbon atoms in a cycloalkylene residue. Additional examples of suitable aliphatic and cycloaliphatic polyisocyanates include, but are not limited to, cyclohexane diisocyanate, methyl cyclohexane diisocyanate, ethyl cyclohexane diisocyanate, propyl cyclohexane diisocyanate, methyl diethyl cyclohexane diisocyanate, propane diisocyanate, butane diisocyanate, pentane diisocyanate, hexane diisocyanate, heptane diisocyanate, octane diisocyanate, nonane diisocyanate, nonane triisocyanate such as 4-isocyanatomethyl-1,8-octane diisocyanate (TIN), decane diisocyanate and triisocyanate, undecane diisocyanate and triisocyanate, and dodecane diisocyanate and triisocyanate, isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), diisocyanatodicyclohexylmethane (DICH ... 12 In one or more embodiments of the present invention, the isocyanate component comprises a polyisocyanate selected from the group consisting of hexamethylene diisocyanate ("HDI") and its isomers, isophorone diisocyanate ("IPDI") and its isomers, norbornane diisocyanate ("NBDI") and its isomers, tetramethylxylyl diisocyanate ("TMXDI") and its isomers, and xylyl diisocyanate ("XDI") and its isomers, and mixtures thereof.

[0028] In some embodiments, the isocyanate reactive component can be a polyether polyol, a polyester polyol, a polycaprolactone polyol, a polycarbonate polyol, a hydroxyl terminated polybutadiene polyol, a natural oil based polyol, a short chain diol, or a combination thereof.

[0029] Examples of suitable polyether polyols may include, but are not limited to, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, polyoxybutylene polyols, and mixtures thereof. Exemplary polyether polyols may include VORANOL™ polyols available from The Dow Chemical Company (Dow Chemical Company) (Midland, MI), PLURACOL™ polyols available from BASF SE (Ludwigshafen, Germany), POLY-G™, POLY-L™, and POLY-Q™ polyols available from Lonza Group AG (Basel, Switzerland), and ACCLAIM™ polyols available from Covestro AG (Leverkusen, Germany). Polytetramethylene ether glycols suitable for use may include POLYTHF™ glycols available from BASF SE (Ludwigshafen, Germany), TERATHANE™ glycols available from Invista Company (Wichita, KS), PTMG™ glycols available from Mitsubishi Chemical Corporation (Tokyo, JP), and PTG™ glycols from Dairen Chemical Corp. (Taipei City, Taiwan, China). Suitable polyoxybutylene-based polyols may include, but are not limited to, polyoxybutylene homopolymer polyols, polyoxybutylene-polypropylene oxide copolymer polyols, and polyoxybutylene-polyethylene oxide copolymer polyols.

[0030] Examples of suitable polyester polyols may include, but are not limited to, aliphatic polyester polyols, aromatic polyester polyols, or copolymers of aliphatic and aromatic polyester polyols, such as STEPANPOL™ polyols available from Stepan Company (Northfield, IL USA), FOMREZ™ polyols available from Chemtura Corporation (Middleburt, CT USA), POLYOL™ polyols available from Kuraray Co., Ltd (Tokyo, JP), DYNACOLL™ polyols available from Evonik Industries AG (Essen, Germany), and DESMODUR™ available from Covestro AG (Leverkusen, Germany).

[0031] In some embodiments, the isocyanate-reactive component can be a polyester polyol comprising: (a) an acidic component comprising the residue of at least one dicarboxylic monomer; and (b) a diol component comprising the residues of: (i) 2,2,4,4-tetraalkyl-1,3-cyclobutanediol (TACD); and (ii) at least one diol or polyol other than TACD, wherein the hydroxyl functionality of the polyester polyol is from 2 to 3. Examples of TACD include 2,2,4,4-tetramethylcyclobutane-1,3-diol (TMCD), 2,2,4,4-tetraethylcyclobutane-1,3-diol, 2,2,4,4-tetra-n-propylcyclobutane-1,3-diol, 2,2,4,4-tetra-n-butylcyclobutane-1,3-diol, 2,2,4,4-tetra-n-pentylcyclobutane-1,3-diol, 2,2,4,4-tetra-n-hexylcyclobutane-1,3-diol, 2,2,4,4-tetra-n-heptylcyclobutane-1,3-diol, 2,2,4,4-tetra-n-octylcyclobutane-1,3-diol. 1,3-diol, 2,2-dimethyl-4,4-diethylcyclobutane-1,3-diol, 2-ethyl-2,4,4-trimethylcyclobutane-1,3-diol, 2,4-dimethyl-2,4-diethyl-cyclobutane-1,3-diol, 2,4-dimethyl-2,4-di-n-propylcyclobutane-1,3-diol, 2,4-n-dibutyl-2,4-diethylcyclobutane-1,3-diol, 2,4-dimethyl-2,4-diisobutylcyclobutane-1,3-diol and 2,4-diethyl-2,4-diisopentylcyclobutane-1,3-diol. In some embodiments, TACD may include TMCD or be TMCD. Examples of suitable diols or polyols other than TACD may include 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 2,2,4-trimethyl-1,3-pentanediol, hydroxypivalylhydroxypivalate, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, ...1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, diol, 2-ethyl-2-isobutyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2,4,4-tetramethyl-1,6-hexanediol, 1,10-decanediol, 1,4-benzenedimethanol, ethylene glycol, 1-3-propanediol, 1-4-propanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, pentanediol, dodecanediol and 2,2-bis(hydroxymethyl)propionic acid (dimethylolpropionic acid).

[0032] Examples of suitable polycaprolactone polyols may include, but are not limited to, CAPA™ polyols available from Ingevity Corporation (North Charleston SC USA), PLACCEL™ polycaprolactone polyols available from DAICEL ChemTech, Inc. (Fort Lee, NJ USA), POLYCAP™ available from Connect Chemicals USA, LLC (Alpharetta, GA USA), and CAPROMER™ available from BASF SE (Ludwigshafen, Germany).

[0033] Examples of suitable polycarbonate polyols may include, but are not limited to, PLACCEL™ polycarbonate polyols available from DAICEL ChemTech, Inc. (Fort Lee, NJ USA), ETERNACOLL™ polycarbonate polyols available from UBE Corp. (Tokyo, JP), CONVERGE™ polyols® available from Saudi Aramco (Dhahran, Saudi Arabia), and DESMOPHEN™ and CARDYON™ polyols available from Covestro AG (Leverkusen, Germany).

[0034] Examples of suitable hydroxyl-terminated polybutadiene polyols may include, but are not limited to, KRASOL™ hydroxyl-terminated polybutadiene polyols available from Cray Valley USA, LLC (PA USA), POLY BD™ hydroxyl-terminated polyols available from Cray Valley USA, LLC (PA USA), and POLYVEST HT™ liquid polybutadiene polyols available from Evonik Industries AG (Essen, Germany).

[0035] Examples of suitable natural oil-based polyols may include, but are not limited to, SOVERMOL™ available from BASF SE (Ludwigshafen, Germany), STEPANPOL™ available from Stepan Company (Northfield, IL USA), EMEROX™ polyols available from Emery Oleochemicals LLC (Cincinnati, OH USA), BiOH™ polyols available from Cargill, Inc. (Wayzata, MN USA), and POLYCIN™ polyols available from Vertellus Chemicals Company (Indianapolis, IN USA).

[0036] Examples of suitable short chain diols may include, but are not limited to, ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, methylpentanediol, dimethylbutanediol, butylethylpropylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD), and triethylene glycol.

[0037] As previously described herein, the hydroxyl value (OH) of the curing agent component may be greater than 350. All individual values ​​and subranges are included and disclosed herein. For example, in some embodiments, the curing agent component may have a hydroxyl value (OH) ranging from a lower limit of greater than 350, 355, 360, or 365 to an upper limit of 1900, 1850, 1825, or 1815. The hydroxyl value (OH) of the curing agent component can be measured according to ASTM D4274.

[0038] In one or more embodiments of the present invention, the range of NCO to OH ratio may be 0.95 to 1.5. All individual values ​​and sub-ranges are included and disclosed herein. For example, in some embodiments, the range of NCO to OH ratio may be from a lower limit of 0.950, 1.0 or 1.02 to an upper limit of 1.5, 1.3, 1.1 or 1.05. The ratio can be calculated based on the NCO content of the isocyanate component and the hydroxyl value of the curing agent component. The calculation is also shown in ASI Adhesives & Sealants Industry Magazine, Vol. 25, No. 5, p. 37 (May 2018) https: / / digital.bnpmedia.com / publication / ?i=491395&article_id=3068591&view=articleBrowser, which is incorporated herein by reference.

[0039] In one or more embodiments of the present invention, the curing agent component may include: (1) one or more isocyanate-reactive compounds; and (2) a catalyst. Examples of suitable isocyanate-reactive compounds may include hydroxyl-terminated isocyanate-reactive compounds or amine-terminated isocyanate-reactive compounds. Hydroxyl-terminated isocyanate-reactive compounds may include polyether polyols, polyester polyols, polycaprolactone polyols, polycarbonate polyols, hydroxyl-terminated polybutadiene polyols, natural oil-based polyols, short-chain diols, and mixtures thereof. Examples of specific hydroxyl-terminated isocyanate-reactive compounds are previously described herein. Amine-terminated isocyanate-reactive compounds may include, but are not limited to, JEFFAMINE™ compounds available from Huntsman Corporation (The Woodlands, TX), VERSALINK™ compounds available from Evonik Industries AG (Essen, Germany), and BAXXODUR™ compounds available from BASF SE (Ludwigshafen, Germany). In some embodiments, the one or more isocyanate-reactive compounds is 2,2,4,4-tetraalkyl-1,3-cyclobutanediol (TACD) as previously described herein.

[0040] As known in the art, the catalyst can be an amine catalyst, a tin-based catalyst, a zinc-based catalyst, a zirconium-based catalyst, a bismuth-based catalyst or a mixture thereof. Examples of suitable catalysts may include, but are not limited to, triethylenediamine, N-methylmorpholine, N-ethylmorpholine, diethylethanolamine, N-cocoylmorpholine, 1-methyl-4-dimethylaminoethylpiperazine, 3-methoxy-N-dimethylpropylamine, N,N-diethyl-3-diethylaminopropylamine, dimethylbenzylamine, dimethyltin dilaurate, dibutyltin dilaurate, stannous octoate, zinc naphthenate, zinc neodecanoate, zinc versalate, bismuth neodecanoate, bismuth versatate, tetrabenzyl zirconium, tetra-tert-butoxy zirconium, tetraisopropoxy zirconium, tetrakis(dimethylamino)zirconium, or diisopropoxybis(2,2,6,6-tetramethyl-3,5-heptanedione)zirconium and mixtures thereof.

[0041] In the embodiments described herein, a method for manufacturing a container lid is also disclosed, and the container lid is suitable for use with a container for storing food or beverages as previously described herein. The method includes: providing a lid body, the lid body being configured to be attached to the neck of the container; reacting an isocyanate component with a curing agent component having a hydroxyl value (OH) greater than 350 along the lid body at a temperature of 60°C to 240°C (optionally 60°C to 140°C) to form a polyurethane elastomer gasket, wherein the polyurethane elastomer gasket is positioned on the lid body so that the polyurethane elastomer gasket can be deformed and compressed when the lid body is attached to the container, and wherein the polyurethane elastomer gasket and the lid body together form a container lid. The lid body can be attached to the neck of the container by a variety of means known to those skilled in the art (e.g., threads, adhesives, etc.).

[0042] Test Method Gel point The gel point of the polyurethane elastomer composition is defined as the time it takes for the composition to reach a tack-free state at 120° C. after mixing the isocyanate component and the curing agent component. The gel point is reported in seconds.

[0043] Tensile Strength Tensile strength is measured according to ASTM D412 using a 100 Newton load cell on an MTS Criterion Model 46. Tensile strength is reported in megapascals (MPa).

[0044] Elongation at break Elongation at break is measured according to ASTM D412 using a 100 Newton load cell on a MTS Criterion Model 46. Elongation at break is reported in percent (%).

[0045] Shore A Hardness Shore A hardness is measured according to ASTM D-2240 using a Shore A gauge from Rex Gauge Company at 25°C.

[0046] NCO content The NCO content of the isocyanate component is measured according to ASTM D 2572. The NCO content is reported in percent (%).

[0047] Hydroxyl (OH) value The hydroxyl value (OH) of the curing agent component is measured according to ASTM D4274.

[0048] Acid value The acid value is measured according to ASTM D664.

[0049] Example The following specific examples are presented to illustrate the processing and performance properties associated with PVC-free sealing materials used in container closures.

[0050] Table 1 - Raw materials

[0051] Polyester polyol A was prepared as follows: 1753.2 g of adipic acid, 1040.6 g of 1,5-pentanediol, 411.8 g of 1,4-cyclohexanedimethanol, 205.9 g of 2,2,4,4-tetramethyl-1,3-cyclobutanediol, 3.41 g of IRGAFOS™ 168 and 3.41 g of WESTON™ 618F were charged into a four-neck 5-liter glass reactor equipped with a mechanical stirrer, a thermocouple, a heated partial condenser (100°C), a Dean-Stark trap, a cooling condenser (15°C) and a nitrogen inlet. The reactor was placed in a heating jacket connected to a temperature controller. With nitrogen enabled, the mixture in the reactor was slowly heated to 110°C. Once the mixture was melted, it was stirred at 200 rpm. With stirring under nitrogen purge, the mixture was heated to 230°C at a heating rate of 0.2°C / min. The mixture was further reacted at 230° C. under a nitrogen blanket. Samples were taken after 6 hours at 230° C. for acid value analysis. If the acid value was greater than 1.0 mg KOH / g, the reaction was continued until the acid value of the reaction mixture reached less than or equal to 1.0 mg KOH / g. The resulting material was a clear liquid at room temperature.

[0052] Comparative Example A was prepared by adding 100 grams of VESTOLIT G 178 and 73 grams of DRAPEX™ 6.8 to a dry 200 Max FlackTek cup. The cup was then placed in a FlackTek DAC 1200-500 VAC and mixed at 2000 rpm for 5 minutes, followed by additional mixing at 2000 rpm under vacuum for 5 minutes. A uniform, viscous, off-white dispersion was obtained. The mixture was then poured into an aluminum mold pretreated to 190° C. to form a sample sheet of approximately 1.9 mm thickness, and the gel point was determined. After curing at 190° C. for 1 hour, the sample was removed from the mold and treated under ambient conditions for two weeks before being tested for physical properties. Shore A hardness, tensile strength and elongation at break were measured, and the results are provided in Table 3.

[0053] An exemplary formulation was prepared as follows: Embodiment 1 of the present invention Isocyanate component: A 500 ml laboratory glass reactor consisting of a 4-neck flask equipped with a mechanical stirrer and a temperature controller was used to produce the isocyanate component. Under a nitrogen blanket, 81.8 grams of DESMODUR™ H were first charged into a laboratory glass reactor. The temperature of the reactor was set to 50°C. Under stirring conditions, 100.0 grams of POLYOL™ P-510 polyol preheated to 60°C was added to the reactor. If the reaction temperature exceeded 95°C, cooling was performed. After the exotherm of the reaction stabilized, the temperature of the reactor was reset to 95°C. The reaction was maintained at 95°C for 5 hours, followed by the addition of 32.1 grams of DESMODUR™ N3300. After mixing for an additional 45 minutes at 95°C, a clear, low-viscosity prepolymer was obtained. The NCO content of the prepolymer was found to be 14.3%.

[0054] Curing agent component: A 500 ml laboratory glass reactor consisting of a 4-neck flask equipped with a mechanical stirrer and a temperature controller was used to prepare the isocyanate reactive component. The temperature of the reactor was set at 65°C. Under N2 purge and stirring conditions, 170.0 grams of POLYOL™ P-510 polyol preheated to 60°C was charged into the reactor, followed by 30.0 grams of 1,4-butanediol and 2.0 grams of K-KAT XK-672. After mixing at 60°C for 45 minutes, a clear, low-viscosity liquid was obtained. The OH value of the mixture was 377.5.

[0055] Polyurethane Elastomer: 50.0 grams of the curing agent component preheated to 65°C and 101.7 grams of the isocyanate component preheated to 65°C were added to a dry 200 Max FlackTek cup. Mixing was performed at 2000 rpm for 1 minute on a FlackTek DAC 1200-500 VAC under vacuum. The mixture was then poured into an aluminum mold preconditioned to 120°C to form a sample sheet of approximately 1.9 mm thickness, and the gel point was determined. After curing at 120°C for 1 hour, the sample was removed from the mold and conditioned at ambient conditions for two weeks before physical property testing was performed. The results are listed in Table 2.

[0056] Embodiment 2 of the present invention Isocyanate component: Example 1 was repeated except that 77.9 g DESMODUR™ H, 100.0 g PH-50 and 31.4 g DESMODUR™ N3300 were used. The prepolymer was a clear, low viscosity liquid at room temperature and had an NCO content of 13.9%.

[0057] Curing agent component: Example 1 was repeated except that 170.0 g of PH-50, 30.0 g of 1,4-butanediol and 2.0 g of K-KAT XK-672 were used. The mixture was a clear viscous liquid at room temperature and had an OH value of 371.5.

[0058] Polyurethane elastomer: Example 1 was repeated except that 103.8 g of the isocyanate component and 50.0 g of the curing agent component were used. The results are listed in Table 2.

[0059] Embodiment 3 of the present invention Isocyanate component: Example 1 was repeated except that 126.4 g of TAKENATE™ 500, 75.0 g of POLYOL™ P-510, 25.0 g of 3-methyl-1,5-pentanediol, and 25.2 g of DESMODUR™ N3300 were used. The prepolymer was a clear, low viscosity liquid at room temperature and had an NCO content of 12.5%.

[0060] Curing agent component: Example 1 was repeated except that 85.0 g of POLYOL™ P-510, 15.0 g of 1,4-butanediol and 1.0 g of K-KAT XK-672 were used. The mixture was a clear, viscous liquid at room temperature and had an OH value of 377.4.

[0061] Polyurethane elastomer: Example 1 was repeated except that 116.7 g of the isocyanate component and 50.0 g of the curing agent component were used. The results are listed in Table 2.

[0062] Embodiment 4 of the present invention Isocyanate component: Example 1 was repeated except that 111.1 g of TAKENATE™ 500, 75.0 g of PTMEG 650, 25.0 g of 3-methyl-1,5-pentanediol, and 37.3 g of DESMODUR™ N3300 were used. The prepolymer was a clear, low viscosity liquid at room temperature and had an NCO content of 12.1%.

[0063] Curing agent component: Example 1 was repeated except that 80.0 g of PTMEG 650, 20.0 g of 1,4-butanediol and 1.0 g of K-KAT XK-672 were used. The mixture was a clear viscous liquid at room temperature and had an OH value of 387.8.

[0064] Polyurethane elastomer: Example 1 was repeated except that 123.5 g of the isocyanate component and 50.0 g of the curing agent component were used. The results are listed in Table 2.

[0065] Embodiment 5 of the present invention Isocyanate component: Example 1 was repeated, except that 88.7 g DESMODUR™ H, 80.0 g POLYOL™ P2010, 20.0 g 1,3 butanediol, and 21.0 g DESMODUR™ N3300 were used. The prepolymer was a clear, low viscosity liquid at room temperature and had an NCO content of 12.6%.

[0066] Curing agent component: Example 1 was repeated except that 69.0 g of POLYOL™ P-510, 11.0 g of 1,4-butanediol and 0.8 g of K-KAT XK-672 were used. The mixture was a clear, viscous liquid at room temperature and had an OH value of 364.6.

[0067] Polyurethane elastomer: Example 1 was repeated except that 91.0 g of the isocyanate component and 40.0 g of the curing agent component were used. The results are listed in Table 2.

[0068] Embodiment 6 of the present invention Isocyanate component: Example 1 was repeated, except that 182.8 g DESMODUR™ H, 160.0 g polyester polyol A, 40.0 g 1,3 butanediol and 42.6 g DESMODUR™ N3300 were used. The prepolymer was a clear, low viscosity liquid at room temperature and had an NCO content of 12.8%.

[0069] Curing agent component: Example 1 was repeated, except that 60.0 g of polyester polyol A, 20.0 g of 1,4-butanediol and 0.8 g of K-KAT XK-672 were used. The mixture was a clear viscous liquid at room temperature and had an OH value of 361.2.

[0070] Polyurethane elastomer: Example 1 was repeated except that 97.7 g of the isocyanate component and 40.0 g of the curing agent component were used. The results are listed in Table 2.

[0071] Table 2 - Results Processing temperature window, °C Gel point, seconds Hardness, Shore A Tensile strength, MPa Elongation at break, % NCO / OH Ratio Example 1 60-140 120 60 9.7 410 1.02 Example 2 60-140 100 70 30.5 427 1.02 Example 3 60-140 120 55 7.4 635 1.03 Example 4 60-140 110 55 7.9 431 1.03 Example 5 60-140 120 60 14.3 509 1.03 Example 6 60-140 100 82 30.1 514 1.03 Comparative Example A 190-220 120 61 6 207 --

[0072] As shown in the above table, the formulations of the present invention exhibit lower processing temperatures, and at the same time, the mechanical properties of the formulations are not affected or significantly improved.

[0073] The dimensions and values ​​disclosed herein are not to be understood as being strictly limited to the exact numerical values ​​cited. Instead, unless otherwise specified, each such dimension is intended to represent the stated value and a functionally equivalent range around that value. For example, a dimension disclosed as "40 mm" is intended to mean "about 40 mm".

[0074] Unless expressly excluded or otherwise limited, each document cited herein (if any), including any cross-referenced or related patents or applications and any patent applications or patents to which this application claims priority or benefit, is hereby incorporated by reference in its entirety. The citation of any document does not admit that it is prior art related to any invention disclosed or claimed herein, or that it alone or in any combination with any one or more other references teaches, suggests or discloses any such invention. In addition, when any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to the term in this document shall prevail.

[0075] Although specific embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various other changes and modifications may be made without departing from the spirit and scope of the present invention. Therefore, it is intended that all such changes and modifications within the scope of the present invention be covered in the appended claims.

Claims

1. A container lid for use with a container suitable for storing food or beverages, the container lid comprising: a cap body configured to be attached to a neck of a container; and a gasket attached to the cover body, the gasket being configured to be deformed and compressed between the cover body and the container, wherein the gasket is made of a sealing material comprising at least 50% by weight of a polyurethane elastomer; wherein the polyurethane elastomer is a reaction product of an isocyanate component and a curing agent component having a hydroxyl value (OH) greater than 350.

2. The container lid according to claim 1, wherein the container lid is a lug screw lid, a Press-on Twist-Off® lid, a capped closure, a crimped lid or a disposable lid, or a metal lid that can be rolled onto the container.

3. The container cap according to claims 1 and 2, wherein the sealing material is substantially free of components that are liquid at room temperature.

4. The container closure of claims 1-3, wherein the polyurethane elastomer gasket is substantially free of polyvinyl chloride.

5. The container cap according to claims 1-4, wherein the sealing material has a Shore A hardness of 50 to 95.

6. The container cap according to claims 1-5, wherein the isocyanate component comprises: i. a polyisocyanate, wherein the polyisocyanate is an aliphatic isocyanate or an alicyclic isocyanate; and ii. Isocyanate-reactive components.

7. The container cap according to claim 6, wherein the polyisocyanate is selected from hexamethylene diisocyanate ("HDI") and its isomers, isophorone diisocyanate ("IPDI") and its isomers, norbornane diisocyanate ("NBDI") and its isomers, tetramethylxylene diisocyanate ("TMXDI") and its isomers, and xylene diisocyanate ("XDI") and its isomers, and mixtures thereof.

8. The container cap according to claim 6 or 7, wherein the isocyanate reactive component is selected from polyether polyols, polyester polyols, polycaprolactone polyols, polycarbonate polyols, hydroxyl-terminated polybutadiene polyols, natural oil-based polyols, short-chain diols and mixtures thereof.

9. The container cap according to claims 6-8, wherein the isocyanate reactive component is a polyester polyol comprising: i. an acidic component comprising the residue of at least one dicarboxyl monomer; and ii. a diol component comprising the residues of: (i) 2,2,4,4-tetraalkyl-1,3-cyclobutanediol (TACD); and (ii) at least one diol or polyol other than TACD, The hydroxyl functionality of the polyester polyol is 2 to 3.

10. The container cap according to claims 1-9, wherein the curing agent component comprises: i. one or more isocyanate-reactive compounds; and ii. Catalyst.

11. The container cap according to claim 10, wherein the one or more isocyanate-reactive compounds are hydroxyl-terminated isocyanate-reactive compounds or amine-terminated isocyanate-reactive compounds.

12. The container cap according to claim 11, wherein the hydroxyl-terminated isocyanate-reactive compound is selected from the group consisting of polyether polyols, polyester polyols, polycaprolactone polyols, polycarbonate polyols, hydroxyl-terminated polybutadiene polyols, natural oil-based polyols, short-chain diols, and mixtures thereof.

13. The container lid of claims 10-12, wherein the one or more isocyanate-reactive compounds is 2,2,4,4-tetraalkyl-1,3-cyclobutanediol.

14. The container cap according to claim 10, wherein the catalyst is selected from the group consisting of amine-based catalysts, tin-based catalysts, zinc-based catalysts, zirconium-based catalysts, bismuth-based catalysts, and mixtures thereof.

15. A method for manufacturing a container lid according to claims 1 to 14, the container lid being suitable for use with a container for storing food or beverages, the method comprising: providing a cap body configured for attachment to a neck of a container; An isocyanate component and a curing agent component having a hydroxyl value (OH) greater than 350 are reacted along a cover body at a temperature of 60°C to 240°C to form a polyurethane elastomer gasket, wherein the polyurethane elastomer gasket is positioned on the cover body so that the polyurethane elastomer gasket can be deformed and compressed when the cover body is attached to a container, and wherein the polyurethane elastomer gasket and the cover body together form a container cover.

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