Method for producing PVC-free container lids

Abstract

A method for manufacturing a container lid for use with a container suitable for storing food or beverage, the method comprising: providing a lid body configured to be attached to a container neck; an isocyanate component and a curing agent component are reacted along the lid body at a temperature of 60 DEG C to 140 DEG C to form a polyurethane elastomer gasket, where the polyurethane elastomer gasket is located on the lid body such that it is deformable and compressible when the lid body is attached to a container, wherein the polyurethane elastomer gasket and the lid body together form a container lid.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to methods of manufacturing container lids, and more particularly, to methods of manufacturing PVC-free container lids that include gaskets formed from polyurethane elastomers. Background Art

[0002] Polyvinyl chloride (PVC) is widely used in food packaging applications, and specifically, they are used as sealing materials in container lids, for example. However, the manufacture, use, and disposal of PVC can pose hazards to the environment and human health. In addition, the presence of PVC in packaging presents compatibility issues, making plastic waste containing PVC and other plastic materials difficult to recycle. Moreover, PVC-based materials typically require the use of plasticizers, such as epoxy soybean oil, which may migrate into the food packaged in the container, thereby contaminating the food.

[0003] On the other hand, PVC materials provide the processing and performance characteristics necessary for container lids. Container lids are typically used with containers made of glass or plastic for storing food and / or beverages. Depending on the use environment, container lids may have different degrees of characteristics. For example, under corrosive conditions, the container lid must not allow corrosive substances to pass through, but still have sufficient elasticity to form a seal. When the container lid is used as a bottle cap closure and the closure is applied and removed (and / or resealed), it is required that the container lid maintain its integrity and not be torn or shredded so that its fragments contaminate the food or beverage. In addition, the container lid should not lose its seal integrity due to deformation. Depending on the type of food and / or liquid contents, the filling temperature may be lower or higher than room temperature (e.g., sterilization), so the requirements for the container lid are even higher.

[0004] Therefore, there is still a need for methods of manufacturing PVC-free container lids for packaging food and beverages that provide similar or improved processing and / or performance characteristics as container lids made of PVC. Summary of the Invention

[0005] Embodiments herein disclose methods of manufacturing container lids suitable for use with containers storing food or beverages. The method includes: providing a lid body configured to be attached to a container neck; reacting an isocyanate component and a curing agent component along the lid body at a temperature of 60°C to 140°C to form a polyurethane elastomer gasket, wherein the polyurethane elastomer gasket is located on the lid body such that it is deformable and compressible when the lid body is attached to the container, and wherein the polyurethane elastomer gasket and the lid body together form the container lid.

[0006] Additional features and advantages of the embodiments will be set forth in the detailed description which follows, and in part will be obvious from the description, or may be learned by practice of the embodiments described herein. It is to be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. Detailed Description

[0007] Reference will now be made in detail to embodiments for manufacturing a container lid. The container lid can be used for packaging food and / or beverages. For example, the container lid described herein can be used with metal or plastic containers suitable for storing food and / or beverages. The container lid can be selectively coupled to the container to form a fluid seal between the container and the environment. However, it should be noted that this is merely an illustrative implementation of the embodiments disclosed herein. The embodiments can be applicable to other technologies that are susceptible to problems similar to those discussed above. For example, the container lid described herein can be used in other packaging applications, such as cosmetics and pharmaceuticals, all of which are within the scope of this embodiment.

[0008] In an embodiment herein, the method includes: providing a lid body configured to be attached to a container neck; reacting an isocyanate component and a curing agent component along the lid body at a temperature of 60°C to 140°C to form a polyurethane elastomer gasket, wherein the polyurethane elastomer gasket is located on the lid body such that it is deformable and compressible when the lid body is attached to the container, and wherein the polyurethane elastomer gasket and the lid body together form a container lid. All individual values and subranges from 60°C to 140°C are included and disclosed herein. For example, in some embodiments, the isocyanate component and the curing agent component react at a temperature of 80°C to 130°C, 80°C to 120°C, or 100°C to 120°C.

[0009] In an embodiment herein, the container lid includes a lid body and a gasket attached to the lid body. The container lid can be a lug screw cap, Press-on lid a cap), a capped, crimped or disposable cap, or a metal cap that can be rolled onto the container. In some embodiments, the cap body includes a top plate portion and a skirt portion extending perpendicularly from the top plate portion, wherein the top plate portion and the skirt portion define a generally cylindrical inner groove. The shape of the top plate portion may generally be circular. In other embodiments, the cap body includes a top plate portion and a skirt portion extending perpendicularly 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 located near the edge of the skirt portion. The lugs may extend radially inward from the skirt portion into the inner groove. Other examples of suitable container caps are described, for example, in U.S. 10,450,449 B2, U.S. 10,189,610 B2 and EP 2509883 B1, which are incorporated herein by reference. The gasket described herein is attached to the cap body and configured for deformation and compression between the cap body and the container. In some embodiments, the gasket is installed in the inner groove of the cap body to the top plate portion and / or the skirt portion.

[0010] The polyurethane elastomer gasket comprises at least 50 wt% of polyurethane elastomer. All individual values and subranges are included and disclosed herein. For example, in some embodiments, the polyurethane elastomer comprises at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt% of the polyurethane elastomer gasket. In other embodiments, the polyurethane elastomer comprises 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 polyurethane elastomer gasket.

[0011] In the embodiments herein, the polyurethane elastomer gasket is substantially free (or alternatively, free) of polyvinyl chloride. As used herein, the term "substantially free" when referring to polyvinyl chloride means that no polyvinyl chloride has been intentionally added to the polyurethane elastomer gasket. As used herein, the term "free" means that the amount of polyvinyl chloride is undetectable. In one or more embodiments herein, the polyurethane elastomer gasket may be substantially free of components that are liquid at room temperature.

[0012] In one or more embodiments herein, the Shore A hardness of the polyurethane elastomer gasket may be 50 to 95. All individual values and subranges are included and disclosed herein. For example, in some embodiments, the Shore A hardness range of the polyurethane elastomer gasket may be 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 durometer in accordance with ASTM D-2240.

[0013] In one or more embodiments of the present disclosure, the isocyanate component may have an NCO content of 5.0% to 25.0%. All individual values and sub-ranges are included and disclosed herein. For example, in some embodiments, the NCO content range of the isocyanate component may be 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 can be determined according to ASTM D2572.

[0014] In some embodiments, the isocyanate component may include a polyisocyanate (which is an aliphatic isocyanate or cycloaliphatic 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, alternatively 4 to 12 carbon atoms, in a linear or branched alkylene residue. Examples of suitable cycloaliphatic polyisocyanates may include cycloaliphatic polyisocyanates having 4 to 18 carbon atoms, alternatively 6 to 15 carbon atoms, in a cycloalkylene residue. Further examples of suitable aliphatic and cycloaliphatic polyisocyanates include, but are not limited to, cyclohexane diisocyanate, methylcyclohexane diisocyanate, ethylcyclohexane diisocyanate, propylcyclohexane diisocyanate, methyldiethylcyclohexane 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 (H 12 MDI), 2-methylpentane diisocyanate (MPDI), 2,2,4-trimethylhexamethylene diisocyanate / 2,4,4-trimethylhexamethylene diisocyanate (TMDI), norbornane diisocyanate (NBDI), xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate, and their dimers, trimers, and mixtures thereof. In one or more embodiments of the present disclosure, the isocyanate component includes 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, tetramethylxylylene diisocyanate (“TMXDI”) and its isomers, and xylylene diisocyanate (“XDI”) and its isomers, and mixtures thereof.

[0015] 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.

[0016] Examples of suitable polyether polyols can include, but are not limited to, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, poly(oxytetramethylene) glycols, and mixtures thereof. Exemplary polyether polyols can include VORANOL available from The Dow Chemical Company (Midland, MI) TM polyols, PLURACOL available from BASF SE (Ludwigshafen, Germany) TM polyols, POLY-G available from Lonza Group AG (Basel, Switzerland) TM 、POLY-L TM and POLY-Q TM polyols, and ACCLAIM available from Covestro AG (Leverkusen, Germany) TM polyols. Suitable polytetramethylene ether glycols can include POLYTHF available from BASF SE (Ludwigshafen, Germany) TM diols, TERATHANE available from Invista Company (Wichita, KS) TM diols, PTMG available from Mitsubishi Chemical Corporation (Tokyo, Japan) TM diols, and PTG available from Dairen Chemical Corp (Taipei City, Taiwan, China) TM diols. Suitable poly(oxytetramethylene) glycols can include, but are not limited to, poly(oxytetramethylene) homopolymer polyols, poly(oxytetramethylene)-poly(oxypropylene) copolymer polyols, and poly(oxytetramethylene)-poly(oxyethylene) copolymer polyols.

[0017] Examples of suitable polyester polyols can include, but are not limited to, aliphatic polyester polyols, aromatic polyester polyols, or copolymers of aliphatic and aromatic polyester polyols, such as STEPANPOL available from Stepan Company (Northfield, IL USA) TM polyols, FOM REZ available from Chemtura Corporation (Middleburt, CT USA)) TMPolyols, POLYOL available from Kuraray Co., Ltd (Tokyo, JP) TM Polyols, DYNACOLL available from Evonik Industries AG (Essen, Germany) TM Polyols, and DESMODUR available from Covestro AG (Leverkusen, Germany) TM 。

[0018] In some embodiments, the isocyanate-reactive component can be a polyester polyol comprising: (a) an acid component comprising residues of at least one dicarboxylic monomer; and (b) a diol component comprising 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 polyester polyol has a hydroxyl functionality of 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, 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-di-n-butyl-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 can comprise or be TMCD. Examples of suitable diols or polyols other than TACD can 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, hydroxypivaloyl hydroxypivalate, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 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 (dihydroxymethylpropionic acid).

[0019] Examples of suitable polycaprolactone polyols can include, but are not limited to: CAPA available from Ingevity Corporation (North Charleston SC USA) TMPolyols, PLACCEL available from DAICEL ChemTech, Inc. (Fort Lee, NJ USA) TM Polycaprolactone polyols, POLYCAP available from Connect Chemicals USA, LLC (Alpharetta, GA USA) TM And CAPROMER available from BASF SE (Ludwigshafen, Germany) TM .

[0020] Examples of suitable polycarbonate polyols can include but are not limited to PLACCEL available from DAICEL ChemTech, Inc. (Fort Lee, NJ USA) TM Polycarbonate polyols, ETERNACOLL available from UBE Corp. (Tokyo, JP) TM Polycarbonate polyols, CONVERGE available from Saudi Aramco (Dhahran, Saudi Arabia) TM And DESMOPHEN available from Covestro AG (Leverkusen, Germany) TM And CARDYON TM Polyols.

[0021] Examples of suitable hydroxyl-terminated polybutadiene polyols can include but are not limited to KRASOL available from Cray Valley USA, LLC (PA USA) TM Hydroxyl-terminated polybutadiene polyols, POLY BD available from Cray Valley USA, LLC (PA USA) TM Hydroxyl-terminated polyols, and POLYVEST HT available from Evonik Industries AG (Essen, Germany) TM Liquid polybutadiene polyols.

[0022] Examples of suitable natural oil-based polyols can include but are not limited to SOVERMOL available from BASF SE (Ludwigshafen, Germany) TM 、STEPANPOL available from Stepan Company (Northfield, IL USA) TM 、EMEROX available from Emery Oleochemicals LLC (Cincinnati, OH USA)TM Polyols, BiOH available from Cargill, Inc. (Wayzata, MN USA) TM Polyols, and POLYCIN available from Vertellus Chemicals Company (Indianapolis, IN USA) TM Polyols.

[0023] Examples of suitable short-chain diols can 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, butylethylpropanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, bis(hydroxyethoxy)benzene, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD), and triethylene glycol.

[0024] In some embodiments herein, the hydroxyl value (OH) of the curing agent component can be from 100 to 1900. All individual values and subranges are included and disclosed herein. For example, in some embodiments, the range of the hydroxyl value (OH) of the curing agent component can be from a lower limit greater than 100, 150, 200, 250, 300, or 350 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.

[0025] In one or more embodiments herein, the ratio range of NCO to OH can be from 0.95 to 1.5. All individual values and subranges are included and disclosed herein. For example, in some embodiments, the ratio range of NCO to OH can be from a lower limit value of 0.950, 1.0, or 1.02 to an upper limit value of 1.5, 1.3, 1.1, or 1.05. This ratio can be calculated based on the NCO content of the isocyanate component and the hydroxyl value of the curing agent component. This calculation is also shown in ASI Adhesives & Sealants Industry Magazine, Volume 25, Issue 5, Page 37 (May 2018) https: / / digital.bnpmedia.com / publication / ?i=491395&article_id=3068591&view=articleBrowser, which is incorporated herein by reference.

[0026] In one or more embodiments of the present disclosure, the curing agent component can include: (1) one or more isocyanate-reactive compounds; and (2) a catalyst. Examples of suitable isocyanate-reactive compounds can include hydroxyl-terminated isocyanate-reactive compounds or amine-terminated isocyanate-reactive compounds. Hydroxyl-terminated isocyanate-reactive compounds can 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 have been previously described herein. Amine-terminated isocyanate-reactive compounds can include, but are not limited to, JEFFAMINE available from Huntsman Corporation (The Woodlands, TX), TM compounds, VERSALINK available from Evonik Industries AG (Essen, Germany), TM compounds, and BAXXODUR available from BASF SE (Ludwigshafen, Germany). TM compounds. In some embodiments, the one or more isocyanate-reactive compounds are 2,2,4,4-tetraalkyl-1,3-cyclobutanediol (TACD) as described above.

[0027] The catalyst can be an amine-based catalyst, tin-based catalyst, zinc-based catalyst, zirconium-based catalyst, bismuth-based catalyst, or a mixture thereof known in the art. Examples of suitable catalysts can include, but are not limited to, triethylenediamine, N-methylmorpholine, N-ethylmorpholine, diethylethanolamine, N-cocomorpholine, 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 versalate, tetrabenzylzirconium, tetra-tert-butoxyzirconium, tetraisopropoxyzirconium, tetra(dimethylamino)zirconium, or zirconium diisopropoxide bis(2,2,6,6-tetramethyl-3,5-heptanedionate), and mixtures thereof.

[0028] Test Methods

[0029] Gel Point

[0030] The gel point of the polyurethane elastomer composition is defined as the time required for the composition to become non-tacky at 120 °C after the isocyanate component and the curing agent component are mixed. The gel point is recorded in seconds.

[0031] Tensile Strength

[0032] The tensile strength was measured on an MTS Criterion Model 46 using a 100 N load cell according to ASTM D412. The tensile strength was recorded in megapascals (MPa).

[0033] Elongation at break

[0034] The elongation at break was measured on an MTS Criterion Model 46 using a 100 N load cell according to ASTM D412. The elongation at break was recorded as a percentage (%).

[0035] Shore A hardness

[0036] The Shore A hardness was measured at 25 °C according to ASTM D - 2240 using a Shore A durometer purchased from Rex Gauge Company.

[0037] NCO content

[0038] The NCO content of the isocyanate component was measured according to ASTM D2572. The NCO content was recorded as a percentage (%).

[0039] Hydroxyl value (OH)

[0040] The hydroxyl value (OH) of the curing agent component was measured according to ASTM D4274.

[0041] Acid value

[0042] The acid value was measured according to ASTM D664.

[0043] Examples

[0044] The following specific examples are given to illustrate the processes and performance characteristics of the PVC - free sealing materials that can be used for container lids.

[0045] Table 1 - Raw materials

[0046]

[0047]

[0048] Polyester polyol A was prepared as follows: In a four - necked 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, 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, and 3.41 g of IRGAFOS were chargedTM 168 and 3.41 grams of WESTON TM 618F. Place the reactor in a heating jacket connected to a temperature controller. Under nitrogen, slowly heat the mixture in the reactor to 110 °C. Once the mixture melts, stir at 200 rpm. While stirring under a nitrogen purge, heat the mixture at a heating rate of 0.2 °C / minute to 230 °C. Allow the mixture to react further under a nitrogen layer at 230 °C. After 6 hours at 230 °C, take a sample for acid value analysis. If the acid value is greater than 1.0 mg KOH / g, continue the reaction until the acid value of the reaction mixture reaches less than or equal to 1.0 mg KOH / g. The resulting substance is a transparent liquid at room temperature.

[0049] Prepare Comparative Example A by adding 100 grams of VESTOLIT G 178 and 73 grams of DRAPEX TM 6.8 to a dry 200 Max FlackTek cup. Then place the cup in a FlackTek DAC 1200 - 500 VAC and mix at 2000 rpm for 5 minutes, then mix at 2000 rpm for another 5 minutes under vacuum. A homogeneous, viscous, off-white dispersion is obtained. Then pour the mixture into an aluminum mold pre-treated at 190 °C to form a sample sheet with a thickness of approximately 1.9 mm, and determine the gel point. After curing at 190 °C for 1 hour, remove the sample from the mold and condition it in the ambient environment for two weeks, then test its physical properties. Measure the Shore A hardness, tensile strength, and elongation at break, and the results are provided in Table 3.

[0050] The exemplary formulation is prepared as follows:

[0051] Example 1 of the present invention

[0052] Isocyanate component: Use a 500 ml laboratory glass reactor consisting of a 4-neck flask equipped with a mechanical stirrer and a temperature controller to produce the isocyanate component. Under a nitrogen layer, first charge 81.8 grams of DESMODUR TM H into the laboratory glass reactor. Set the temperature of the reactor to 50 °C. While stirring, add 100.0 grams of POLYOL TM P-510 polyol preheated to 60 °C to the reactor. If the reaction temperature exceeds 95 °C, perform cooling. After the exotherm of the reaction tends to level off, reset the temperature of the reactor to 95 °C. Keep the reaction at 95 °C for 5 hours, then add 32.1 grams of DESMODUR TM N3300. After remixing at 95 °C for 45 minutes, a transparent, low-viscosity prepolymer is obtained. The NCO content of the prepolymer is found to be 14.3%.

[0053] Hardener 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-reactive component. The temperature of the reactor was set at 65 °C. Under N2 purge and agitation, 170.0 g of POLYOL preheated to 60 °C was charged into the reactor, and then 30.0 g of 1,4-butanediol and 2.0 g of K-KAT XK-672 were added. After mixing at 60 °C for 45 minutes, a transparent, low-viscosity liquid was obtained. The OH value of this mixture was 377.5. TM The P-510 polyol was charged into the reactor, and then 30.0 g of 1,4-butanediol and 2.0 g of K-KAT XK-672 were added. After mixing at 60 °C for 45 minutes, a transparent, low-viscosity liquid was obtained. The OH value of this mixture was 377.5.

[0054] Polyurethane Elastomer: In a dry 200 Max FlackTek cup, 50.0 g of the hardener component preheated to 65 °C and 101.7 g of the isocyanate component preheated to 65 °C were added. Under vacuum, mixing was carried out at 2000 rpm for 1 minute on a FlackTek DAC 1200-500VAC. Then the mixture was poured into an aluminum mold pre-treated at 120 °C to form a sample sheet with a thickness of about 1.9 mm, and the gel point was determined. After curing at 120 °C for 1 hour, the sample was taken out of the mold and treated in the ambient environment for two weeks, and then its physical properties were tested. The results are listed in Table 2.

[0055] Example 2 of the Present Invention

[0056] Isocyanate Component: Example 1 was repeated, except that 60.4 g of DESMODUR TM H, 100.0 g of PTMEG 650 and 40.1 g of DESMODUR TM N3300 were used. The prepolymer was a transparent, low-viscosity liquid at room temperature, and its NCO content was 12.8%.

[0057] Hardener Component: Example 1 was repeated, except that 180.0 g of PH-50, 20.0 g of 1,4-butanediol and 2.0 g of K-KAT XK-672 were used. The mixture was a transparent, low-viscosity liquid at room temperature, and its OH value was 319.5.

[0058] Polyurethane Elastomer: Example 1 was repeated, except that 96.7 g of the isocyanate component and 50.0 g of the hardener component were used. The results are listed in Table 2.

[0059] Example 3 of the Present Invention

[0060] Isocyanate Component: Example 1 was repeated, except that 73.7 g of DESMODUR TM H, 100.0 g of PC-1011P-210 and 43.4 g of DESMODUR TMN3300. The prepolymer is a transparent, low-viscosity liquid at room temperature, and its NCO content is 13.9%.

[0061] Curing agent component: Repeat Example 1, except that 147.2 g of PC-1011-55, 12.8 g of 1,4-butanediol, and 1.6 g of K-KAT XK-672 are used. The mixture is a transparent viscous liquid at room temperature, and its OH value is 150.3.

[0062] Polyurethane elastomer: Repeat Example 1, except that 68.7 g of the isocyanate component and 80.0 g of the curing agent component are used. The results are listed in Table 2.

[0063] Example 4 of the present invention

[0064] Isocyanate component: Repeat Example 1, except that 77.9 g of DESMODUR TM H, 100.0 g of PH-50, and 31.4 g of DESMODUR TM N3300. The prepolymer is a transparent, low-viscosity liquid at room temperature, and its NCO content is 13.9%.

[0065] Curing agent component: Repeat Example 1, except that 170.0 g of PH-50, 30.0 g of 1,4-butanediol, and 2.0 g of K-KAT XK-672 are used. The mixture is a transparent viscous liquid at room temperature, and its OH value is 371.5.

[0066] Polyurethane elastomer: Repeat Example 1, except that 103.8 g of the isocyanate component and 50.0 g of the curing agent component are used. The results are listed in Table 2.

[0067] Example 5 of the present invention

[0068] Isocyanate component: Repeat Example 1, except that 77.9 g of DESMODUR TM H, 100.0 g of PH-50, and 31.4 g of DESMODUR TM N3300. The prepolymer is a transparent, low-viscosity liquid at room temperature, and its NCO content is 13.9%.

[0069] Curing agent component: Repeat Example 1, except that 170.0 g of PH-100, 30.0 g of 1,4-butanediol, and 2.0 g of K-KAT XK-672 are used. The mixture is a transparent viscous liquid at room temperature, and its OH value is 284.8.

[0070] Polyurethane elastomer: Repeat Example 1, except that 79.6 g of the isocyanate component and 50.0 g of the curing agent component are used. The results are listed in Table 2.

[0071] Example 6 of the present invention

[0072] Isocyanate component: Repeat Example 1, except that 77.9 g of DESMODUR TM H, 100.0 g of PH-50 and 31.4 g of DESMODUR TM N3300 are used. The prepolymer is a transparent, low-viscosity liquid at room temperature, and its NCO content is 13.9%.

[0073] Curing agent component: Repeat Example 1, except that 102.0 g of DESMOPHEN TM C2202, 18.0 g of 1,4-butanediol and 1.2 g of K-KAT XK-672 are used. The mixture is a transparent viscous liquid at room temperature, and its OH value is 234.6.

[0074] Polyurethane elastomer: Repeat Example 1, except that 78.6 g of the isocyanate component and 60.0 g of the curing agent component are used. The results are listed in Table 2.

[0075] Example 7 of the present invention

[0076] Isocyanate component: Repeat Example 1, except that 126.4 g of TAKENATE TM 500, 75.0 g of POLYOL TM P-510, 25.0 g of 3-methyl-1,5-pentanediol and 25.2 g of DESMODUR TM N3300 are used. The prepolymer is a transparent, low-viscosity liquid at room temperature, and its NCO content is 12.5%.

[0077] Curing agent component: Repeat Example 1, except that 85.0 g of POLYOL TM P-510, 15.0 g of 1,4-butanediol and 1.0 g of K-KAT XK-672 are used. The mixture is a transparent viscous liquid at room temperature, and its OH value is 377.4.

[0078] Polyurethane elastomer: Repeat Example 1, except that 116.7 g of the isocyanate component and 50.0 g of the curing agent component are used. The results are listed in Table 2.

[0079] Example 8 of the present invention

[0080] Isocyanate component: Repeat Example 1, except that 111.1 g of TAKENATE TM 500, 75.0 g of PTMEG 650, 25.0 g of 3-methyl-1,5-pentanediol and 37.3 g of DESMODURTM N3300. The prepolymer is a transparent, low-viscosity liquid at room temperature, and its NCO content is 12.1%.

[0081] Curing agent component: Repeat Example 1, except that 80.0 g of PTMEG 650, 20.0 g of 1,4-butanediol, and 1.0 g of K-KAT XK-672 are used. The mixture is a transparent viscous liquid at room temperature, and its OH value is 387.8.

[0082] Polyurethane elastomer: Repeat Example 1, except that 123.5 g of the isocyanate component and 50.0 g of the curing agent component are used. The results are listed in Table 2.

[0083] Example 9 of the present invention

[0084] Isocyanate component: Repeat Example 1, except that 88.7 g of DES MODUR TM H, 80.0 g of POLYOL TM P2010, 20.0 g of 1,3-butanediol, and 21.0 g of DESMODUR TM N3300. The prepolymer is a transparent, low-viscosity liquid at room temperature, and its NCO content is 12.6%.

[0085] Curing agent component: Repeat Example 1, except that 69.0 g of POLYOL TM P-510, 11.0 g of 1,4-butanediol, and 0.8 g of K-KAT XK-672 are used. The mixture is a transparent viscous liquid at room temperature, and its OH value is 364.6.

[0086] Polyurethane elastomer: Repeat Example 1, except that 91.0 g of the isocyanate component and 40.0 g of the curing agent component are used. The results are listed in Table 2.

[0087] Example 10 of the present invention

[0088] Isocyanate component: Repeat Example 1, except that 182.8 g of DESMODUR TM H, 160.0 g of polyester polyol A, 40.0 g of 1,3-butanediol, and 42.6 g of DESMODUR TM N3300. The prepolymer is a transparent, low-viscosity liquid at room temperature, and its NCO content is 12.8%.

[0089] Curing agent component: Repeat Example 1, 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 are used. The mixture is a transparent viscous liquid at room temperature, and its OH value is 361.2.

[0090] 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.

[0091] Example 11 of the present invention

[0092] Isocyanate component: The same as in Example 10 of the present invention.

[0093] Curing agent component: Example 1 was repeated, except that 88.4 g of polyester polyol A, 15.6 g of 1,4-butanediol and 1.0 g of K-KAT XK-672 were used. The mixture was a transparent viscous liquid at room temperature, and its OH value was 243.1.

[0094] Polyurethane elastomer: Example 1 was repeated, except that 77.7 g of the isocyanate component and 52.0 g of the curing agent component were used. The results are listed in Table 2.

[0095] Example 12 of the present invention

[0096] Isocyanate component: The same as in Example 10 of the present invention.

[0097] Curing agent component: Example 1 was repeated, except that 108.0 g of polyester polyol A, 12.0 g of 1,4-butanediol and 1.2 g of K-KAT XK-672 were used. The mixture was a transparent viscous liquid at room temperature, and its OH value was 184.1.

[0098] Polyurethane elastomer: Example 1 was repeated, except that 67.9 g of the isocyanate component and 60.0 g of the curing agent component were used. The results are listed in Table 2.

[0099] Table 2 - Results

[0100]

[0101] As shown in the above table, the formulations of the present invention exhibit a lower processing temperature, and at the same time, the mechanical properties of the formulations are not affected or are significantly improved.

[0102] The dimensions and values disclosed herein should not be construed as being strictly limited to the exact numerical values recited. On the contrary, unless otherwise specified, each such dimension is intended to represent the recited value and a functionally equivalent range around that value. For example, a dimension disclosed as "40 mm" is intended to represent "about 40 mm".

[0103] Each document (if any) cited herein, including any cross-referenced or related patent or application and any patent application or patent from which this application claims priority or the benefit of its rights, is hereby incorporated by reference in its entirety, unless expressly excluded or otherwise limited. The citation of any document does not represent an admission that it is prior art to any invention disclosed or claimed herein, nor does it represent an admission that it alone, or in combination with any other one or more references, teaches, suggests or discloses any such invention. Further, if the meaning or definition of a term in this document conflicts with the meaning or definition of the same term incorporated by reference into this document, the meaning or definition assigned to that term in this document shall govern.

[0104] While specific embodiments of the invention have been shown and described, it will be apparent to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, in the appended claims, the invention is intended to cover all such changes and modifications that fall within the scope of the invention.

Claims

1. A method for manufacturing a container lid for use with a container suitable for storing food or beverages, the method comprising: Providing a lid body configured to be attached to the neck of a container; Reacting an isocyanate component and a curing agent component along the lid body at a temperature of 60°C to 140°C to form a polyurethane elastomer gasket, wherein the polyurethane elastomer gasket is located on the lid body such that it is deformable and compressible when the lid body is attached to the container, and wherein the polyurethane elastomer gasket and the lid body together form the container lid.

2. The method according to claim 1, wherein the container lid is a lug twist-off lid, a Press 'n Seal® lid, a capped lid, a crimped lid or a disposable lid, or a metal lid that can be rolled onto the container.

3. The method according to claims 1 and 2, wherein the polyurethane elastomer gasket is substantially free of components that are liquid at room temperature.

4. The method according to claims 1-3, wherein the polyurethane elastomer gasket is substantially free of polyvinyl chloride.

5. The method according to claims 1-4, wherein the Shore A hardness of the polyurethane elastomer gasket is 50 to 95.

6. The method according to claims 1-5, wherein the isocyanate component comprises: i. A polyisocyanate, which is an aliphatic isocyanate or a cycloaliphatic isocyanate; and ii. An isocyanate-reactive component.

7. The method 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, tetramethylxylylene diisocyanate ("TMXDI") and its isomers, and xylylene diisocyanate ("XDI") and its isomers, and mixtures thereof.

8. The method 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 and short-chain diols, or combinations thereof.

9. The method according to claims 6-8, wherein the isocyanate-reactive component is a polyester polyol, which comprises: i. An acid component comprising residues of at least one dicarboxylic monomer; and ii. A diol component comprising residues of (a) 2,2,4,4-tetraalkyl-1,3-cyclobutanediol (TACD); and (b) at least one diol or polyol other than TACD, wherein the hydroxyl functionality of the polyester polyol is 2 to 3.

10. The method according to claims 1-9, wherein the curing agent component comprises: i. One or more isocyanate-reactive compounds; and ii. A catalyst.

11. The method 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 method according to claim 11, wherein the hydroxy-terminated isocyanate-reactive compound is selected from polyether polyols, polyester polyols, polycaprolactone polyols, polycarbonate polyols, hydroxy-terminated polybutadiene polyols, natural oil-based polyols, short-chain diols, or mixtures thereof.

13. The method according to claims 10-12, wherein the one or more isocyanate-reactive compounds are 2,2,4,4-tetraalkyl-1,3-cyclobutanediol.

14. The method according to claim 8, wherein the catalyst is selected from amine-based catalysts, tin-based catalysts, zinc-based catalysts, zirconium-based catalysts, bismuth-based catalysts, and mixtures thereof.

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