Food contact safe sterilization materials

Abstract

The present invention provides a food-contact-safe, bacteria-repellent plastic selected from modified thermoplastics, vulcanized silicone rubber, or modified base plastics. The plastic includes an anti-biofouling agent, comprising approximately 0.1 to 20% by weight of the total plastic weight; and one or more of a filler, a carrier, a release agent, a curing agent, and / or an oil component, each comprising approximately 0.1 to 2% by weight of the total plastic weight. The anti-biofouling agent forms a hydrated layer on the plastic that repel bacteria, including Escherichia coli and Staphylococcus aureus. After combining the anti-biofouling agent and one or more other components, the plastic's optical and mechanical properties, including light transmittance, tensile strength, impact strength, hardness, and / or heat distortion temperature, change by less than 10%.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. patent application 63 / 129,616, filed on December 23, 2020, the disclosure of which is incorporated herein by reference. Technical Field

[0003] The invention relates to a food contact safe bacteria-repellent material. Background Art

[0004] Plastics are food contact materials (FCMs) used in the manufacture of articles (FCAs) that come into contact with food. They are used during the production, processing, transportation, handling, and storage of food. However, plastic surfaces are potential sites for bacterial growth, often forming a slimy film of bacteria called a biofilm. Biofilms pose a threat to human health and increase the chances of microbial infection.

[0005] Introducing biocides or antimicrobials to plastic surfaces, such as by chemical or radiation treatment to bind heavy metals such as silver and their derivatives to the plastic surface, is not considered safe for food contact. A safe, non-leaching, biocide-free solution that prevents adhesion and colonization of the plastic, making the plastic surface resistant to bacterial growth, is one alternative to biocides or antimicrobial active substances that may be considered for plastics intended for food contact, but should still comply with the corresponding regulations for food contact materials.

[0006] Most current, non-leaching, biocide-free solutions for repelling bacterial attachment and colonization on plastic surfaces involve introducing a hydrophilic layer onto the target plastic before or during extrusion through physical, chemical, or covalent bonding. Known hydrophilic agents or additives for forming a hydrophilic layer on plastics include polyethylene glycol (PEG), chitosan, polycations, and diionic polymers. These hydrophilic layers have an antifouling effect on nonspecific attachment and potential colonization of bacterial growth on plastic surfaces.

[0007] When using traditional methods to modify fungicides, the following problems exist:

[0008] (1) Changes in physical properties (such as mechanical properties, transparency, and HDT of modified PCT; mechanical properties of PP, and hardness of silicone rubber);

[0009] (2) Due to other external factors (such as manufacturing constraints), it may be difficult to select a hydrophilic agent that matches the target plastic. For example, an incompatible hydrophilic agent may cause screw surface slippage during the manufacturing process (for modified PCT and PP).

[0010] (3) It is impossible to directly mix silicone rubber with hydrophilic agent during the two-roll mixing process. Silicon oxide nanoparticles help to mix the antifouling agent and raw rubber. Summary of the Invention

[0011] In view of the above problems, the first aspect of the present invention relates to a food contact safe bacteria repellent material. The material is selected from thermoplastics or elastomers, and the material comprises:

[0012] One or more anti-biofouling agents, in an amount of about 0.1 to 20 wt % based on the total weight of the plastic; and

[0013] One or more fillers, carriers, release agents, curing agents and / or oil components, each of which constitutes about 0.1 to 2 weight percent of the total weight of the plastic; one or more anti-biofouling agents forming a hydrated layer on the plastic that is at least 92.1% repellent to bacteria, including Escherichia coli and Staphylococcus aureus; and optical and mechanical properties of the plastic, including light transmittance, tensile strength, impact strength, hardness and / or heat distortion temperature, are altered by less than 10% after being combined with the anti-biofouling agent and one or more other ingredients in addition to the anti-biofouling agent.

[0014] In a first embodiment, the thermoplastic is selected from modified polycyclohexane dimethyl terephthalate (modified PCT) or polypropylene (PP) and copolymers thereof. More specifically, copolymers of polypropylene include polypropylene impact copolymer (PPIC).

[0015] The one or more anti-biofouling agents can be one or more of polyols and their derivatives. More specifically, the one or more anti-biofouling agents include polyethylene glycol sorbitan monolaurate, polyethylene glycol sorbitan monooleate, poly(ethylene glycol) sorbitan hexaoleate, cetearyl stearate-20, poly(propylene glycol) distearate, poly(ethylene glycol) dimethylsiloxane, poly(ethylene oxide)-poly(propylene oxide)-poly, and alkyl polyethylene glycol ethers.

[0016] Alkyl polyglycol ether can be represented by the following formula:

[0017]

[0018] wherein n is an integer from 16 to 18.

[0019] Polyethylene glycol sorbitol hexaoleate can be represented by the following formula:

[0020]

[0021] Where n is an integer from 6 to 9.

[0022] Polyethylene glycol sorbitan monooleate can be represented by the following formula:

[0023]

[0024] Polyethylene glycol-polypropylene ether-polyethylene glycol can be represented by the following formula:

[0025]

[0026] Polyethylene glycol distearate can be represented by the following formula:

[0027]

[0028] Where n is an integer of 8 or 150.

[0029] Polyoxypropylene glyceryl ether can be represented by the following formula:

[0030]

[0031] The sum of A+B+C = 46 to 54.

[0032] Polyethylene glycol dimethyl siloxane can be represented by the following formula:

[0033]

[0034] The sum of x and y is equal to its hydrophile-lipophile balance (HLB), which is 12.

[0035] The one or more anti-biofouling agents may be present in an amount of about 0.1% to 10% by weight.

[0036] The filler in the first embodiment is a reinforcing filler comprising one or more nano-sized inorganic particles.

[0037] In the first embodiment, the content of the inorganic particles as fillers is about 0.1% to 1% by weight.

[0038] In the first embodiment, the inorganic particles used as fillers include fumed silica treated with hexamethyldisilazane, dimethylpolysiloxane, and polydimethylsiloxane.

[0039] The carrier in the first embodiment is represented by the following formula:

[0040]

[0041] wherein R1 and R2 are independently hydrocarbon moieties and each hydrocarbon moiety contains about 10 to 30 carbon atoms having a straight or branched chain.

[0042] More specifically, the carrier is present in an amount of about 0.1% to about 1% by weight.

[0043] In addition, the carrier in the first embodiment includes stearoyl palmitate, stearoyl behenate, stearyl stearate, palmitoyl palmitate, and myristyl myristate.

[0044] In a second embodiment, the elastomer is solid silicone rubber.

[0045] The filler in the second embodiment comprises silica.

[0046] The oil in the second embodiment may be silicone oil containing hydroxyl silicone oil.

[0047] The one or more anti-biofouling agents of the second embodiment include one or more polyethylene glycol and fatty acid groups.

[0048] More specifically, the one or more anti-biofouling agents include polyethylene glycol fatty acid esters, polyoxyethylene lauryl ether, polyethylene glycol dimethylsiloxane, trimethoxysilylpropoxy polyethylene oxide methyl ether, and polyethylene glycol distearate.

[0049] The curing agent in the second embodiment can be 2,4-dichlorobenzoyl peroxide and 1,1,4,4-tetramethyltetramethylenediperoxide di-tert-butyl.

[0050] A food contact article is provided, comprising the material of any one embodiment of the present invention.

[0051] The second aspect of the present invention provides a method for preparing the food contact safe bacteria repellent material of the present invention.

[0052] In a first embodiment, a method for preparing a food contact safe and bacteria repellent material by selecting a thermoplastic material from modified polycyclohexene dimethyl terephthalate or polypropylene includes:

[0053] preparing a masterbatch comprising mixing modified polycyclohexane dimethyl terephthalate or polypropylene and copolymers thereof with one or more anti-biofouling agents and one or more components of fillers, carriers, release agents, curing agents and / or oils;

[0054] The masterbatch is added into thermoplastic plastic at a weight percentage of 1% to 25% for molding.

[0055] In a second embodiment, a method for preparing a food contact safe, bacteria repellent material includes:

[0056] mixing raw silicone rubber, one or more anti-biofouling agents, a filler (e.g., silica), and a loading (curing) agent in a rubber mixer to form a mixture;

[0057] The mixture is compression-molded and vulcanized to obtain vulcanized silicone rubber;

[0058] The vulcanized silicone rubber is post-cured in an oven to obtain an elastomer. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] The present disclosure will be more fully understood from the detailed description given below, which is intended to illustrate only and not to limit the scope of the present disclosure, in which:

[0060] Figure 1 is a schematic diagram illustrating one embodiment of the present invention, which involves using a processing aid to assist the hydrophilic portion of a hydrophilic additive in transitioning from a melt phase to a liquid state and directing it to the surface of a substrate plastic during the cooling stage after extrusion.

[0061] Figure 2 A typical example of a twin-screw extrusion process for preparing a bacteriostatic polymer structure from a base resin having a bacteriostatic modifier according to one embodiment of the present invention is schematically shown.

[0062] Figure 3 shows how to Figure 3A )Bottle preforms, ( Figure 3B ) lid, and ( Figure 3C ) process flow for testing the sterilization efficiency of plastic samples manufactured in nozzles. DETAILED DESCRIPTION

[0063] The present invention will be described in detail by the following examples / embodiments, with accompanying drawings. It should be understood that the specific examples are provided for illustrative purposes only and should not be construed in a limiting manner.

[0064] Example

[0065] Swab test to assess the bacteria repellency of plastics

[0066] Two samples were swab-tested using the following protocol to evaluate the repellency. The repellency, or bacteriostatic properties, of a plastic can be determined by measuring the amount of bacteria adhering to a sample made from a repellent base plastic blend compared to a base plastic without any repellent additives. Plastic samples were prepared into thin sheets of a specific size and first incubated for a fixed time with an inoculum containing a known bacterial cell count. The inoculum preparation and bacterial culture procedures followed the protocols of industrial standards JIS Z 2801 or ISO 22196, where the test and control pieces were incubated at 37°C ± 1°C and a relative humidity of not less than 90% for 24 hours ± 1 hour. One Gram-positive bacterial strain (e.g., Staphylococcus aureus) and one Gram-negative bacterial strain (e.g., Escherichia coli) were used as representative test microorganisms outlined in the standards. After incubation, the sample underwent a bacterial clearance step by draining the test inoculum from the sample, rinsing, and serially diluting it with 0.9% saline to completely remove the inoculum. Adherent bacteria on the sample surface were collected using a swab applicator; the collected bacteria represented species that favor colonization and biofilm growth. After serial dilution, the collected bacteria are plated onto agar plates in standard 90 mm diameter Petri dishes, and cell viability is quantified based on colony forming units (CFUs) for each sample. Figure 3 illustrates the processing workflow for the in-house repellency test.

[0067] Typically, multiple replicates of 4 cm x 4 cm or 5 cm x 5 cm were prepared for each sample. Bacterial suspensions of Staphylococcus aureus and Escherichia coli were prepared. Three replicates of each plastic sample were inoculated with 0.4 ml or 1 ml of each bacterial suspension. The inoculated samples were incubated at 37°C for 24 hours for Staphylococcus aureus and 24 to 48 hours for Escherichia coli. Subsequently, the samples were removed and washed with 8 ml of saline. Samples inoculated with Staphylococcus aureus were washed three times; samples inoculated with E. coli were washed once. Remaining surface bacteria were collected using 3M swabs. The contents of the swabs were spread on agar plates and incubated at 37°C for 24 hours. The colonies formed on the agar plates after incubation were then counted.

[0068] The bacteriostatic properties of modified PCT are 94.4% and 92.1% in terms of inhibition of colony forming units (CFU) of Escherichia coli and Staphylococcus aureus, respectively; the bacteriostatic properties of modified polypropylene against Escherichia coli and Staphylococcus aureus are 96.1% and 99.9%, respectively; and the bacteriostatic properties of modified silicone rubber against Escherichia coli and Staphylococcus aureus are both 99.9%.

[0069] The following series of tests are intended to demonstrate that the mechanical, physical and / or optical properties of the plastic are not substantially altered, for example to within 10% of the original, after incorporation of the anti-biofouling agent and other components according to certain embodiments of the present invention.

[0070] Example 1 - Bacteria-Repellent Modified Poly(Cyclohexanedimethyl Terephthalate) (Modified PCT or "Tritan") Plastic

[0071] A masterbatch was formed by mixing 100 grams of modified PCT (Tritan) base plastic with 4 grams of myristyl palmitate as a carrier, 8 grams of cetearyl stearate and 8 grams of poly(ethylene glycol) sorbitan hexaoleate as anti-biofouling compounds, and 1 gram of fumed silica. The masterbatch was combined with the base plastic in a 1:9 weight ratio and injection molded at a temperature of 220°C (front end) to 275°C (back end) to produce sterilization-repellent plastic bottle preforms. The preforms were then blown into drinking bottles.

[0072] The drinking bottles were subjected to swab tests (as described above) to compare the repellency of the bacteriostatic plastic (A1) with that of the comparative plastic (control). Table 1 shows the reduction in colony forming units of E. coli and S. aureus on bottle samples made from the different plastics.

[0073] In addition, two other samples were made into 4 cm x 4 cm sheet samples, namely A2 and A3, which were also based on bacteriostatic Tritan modified with an anti-biofouling compound and one or more additives, and their bacteriostatic properties were tested based on the same swab test protocol. Samples A2 and A3 were prepared by injection molding Tritan using two different masterbatches to form sheet samples, wherein the Tritan:masterbatch ratio in sample A2 was 1:7, while the Tritan:masterbatch ratio in sample A3 was 1:4; and the masterbatch for preparing sample A2 contained Tritan, 2phr Croda 100, 4phr Eumulgin B2, 0.5phr R8200 and 4 phr poly(ethylene oxide)-poly(propylene oxide)-polyethylene oxide ("Pluronic F127"); the masterbatch used to prepare Sample A3 contained Tritan, 2 phr Croda 100, 4phr Atlas G1096, 4phr Eumulgin B2 and 0.5phr R8200; Table 1 also summarizes their corresponding repellency against Staphylococcus aureus and Escherichia coli.

[0074] Table 1:

[0075] Sample name Staphylococcus aureus Escherichia coli A1 99.9％ 93.6％ A2 99.9％ 69.9％ A3 99.9％ 96.4％

[0076] As can be seen in Table 1, when exposed to E. coli, the bacteria-repellent plastic sample A1 produced according to the present invention reduced the number of E. coli bacteria in the swab test by 93.6% compared to the comparative plastic (control). When exposed to Staphylococcus aureus, the bacteria-repellent plastic sample A1 produced according to the present invention reduced the number of Staphylococcus aureus bacteria in the swab test by over 99.9% compared to the comparative plastic (control). Samples A2 and A3, manufactured in the form of plastic sheets, also exhibited similar repellency against Staphylococcus aureus. However, sample A2 did not exhibit satisfactory repellency against E. coli, while sample A3 did, exhibiting the highest repellency of the three samples. These results indicate that the bacteria-repellent plastic sample A1, which is Tritan modified with a carrier, two anti-biofouling compounds, and a filler, exhibited high repellency against both E. coli and Staphylococcus aureus, particularly against Staphylococcus aureus, achieving a reduction of up to 99.9%. Sample A3, which also contained two other anti-biofouling compounds and other additives including a slip agent, also exhibited high repellency against both bacterial strains. In addition, the sterile plastic sample bottle A1 passed the EU Commission Regulation No. 10 / 2011 evaluation (overall migration and heavy metals) test and LFGB sensory inspection - smell and taste test.

[0077] Tensile strength test results of bacteria-repellent Tritan sample A1

[0078] To evaluate the tensile strength of plastic sample A1, standard dumbbell-shaped specimens were prepared from the sample sheets produced by the single-screw extruder using a sample cutter, such as the SDL-200HC2 sample cutter. The yield tensile strength (MPa) was evaluated, which indicates the maximum load the specimen can withstand before permanent deformation. On the stress-strain curve, it is shown as the tensile stress at the first peak. The tensile strength of the formulation is determined by The 314 Electromechanical Universal Testing System performs tests according to ASTM D638, "Standard Test Method for Tensile Properties of Plastics." Young's modulus and maximum elongation can be determined from the generated stress-strain curves. Samples are loaded into the grips using a 12 mm gauge length. For ABS, the sample is strained at a rate of 6 mm / min.

[0079] Table 2:

[0080]

[0081]

[0082] From the results in Table 2, it can be seen that incorporating 0.8 wt% of cetyl alcohol and poly(ethylene glycol) sorbitan hexaoleate into Tritan does not substantially affect the tensile strength of the plastic, which means that the polymer matrix of Tritan remains intact without the incorporation.

[0083] Impact strength test results of bacteria-repellent Tritan sample A1

[0084] The impact strength of antimicrobial plastics was determined based on the standard and experimental protocol of ASTM D-256, which is the "Standard Test Method for Izod Pendulum Impact Strength of Plastics." Plastic strip samples of specific dimensions were prepared using an injection molding machine (Thermo Scientific™, MiniJet). A notch was then made at a specified location on each plastic strip sample. The impact strength was determined by applying a standardized pendulum-type hammer to the plastic sample and measuring its resistance to breaking from a single swing. The Izod impact strength was tested using a standardized Kunlun impact tester, in accordance with ASTM D256-10, with an impact energy of 5.5J.

[0085] Table 3:

[0086]

[0087] From the results in Table 3, it can be seen that the addition of 0.8 wt% of cetearyl alcohol polyether and polyethylene glycol sorbitan hexaglycolate into Tritan does not significantly affect the impact strength of the plastic, which means that the polymer matrix of Tritan remains in its original state without the incorporation.

[0088] Heat deformation temperature test results of sterile Tritan sample A1

[0089] The thermal deflection temperature is determined using ISO 75. Plastics are molded into bars measuring 80 mm x 10 mm x 4 mm. The bar specimens are placed under a deflection measurement device (JJ tester). A load of 0.45 MPa is applied to each specimen. The specimens are then immersed in a silicone oil bath where the temperature is increased at a rate of 2°C per minute until the specimen deflects 0.32 mm.

[0090] Table 4:

[0091]

[0092] From the results in Table 4, it can be seen that the incorporation of 0.8 wt% of cetyl alcohol and poly(ethylene glycol) sorbitan hexaoleate into Tritan does not substantially affect the plastic's heat deflection temperature (deformation temperature under a specific load), which means that in the absence of such incorporation, the polymer matrix of Tritan remains intact.

[0093] Transmittance test results of bacteria-repellent Tritan sample A1

[0094] Transmittance is characterized according to ASTM D1003 Procedure A. Plastic samples are cut into 50 mm diameter disks or squares of the same side length. The specimens should have substantially planar parallel surfaces free of dust, grease, scratches, and blemishes. The transmittance (%) of the samples is measured using a GW-820 automatic haze meter.

[0095] Table 5:

[0096]

[0097]

[0098] From the results in Table 5, it can be seen that incorporating 0.8 wt% of cetyl alcohol and poly(ethylene glycol) sorbitan hexaoleate into Tritan does not substantially affect the transmittance of the plastic, which means that in the absence of such incorporation, the polymer matrix of Tritan still maintains its original transparency.

[0099] Example 2 - Bacteria-repellent polypropylene (PP) plastic

[0100] 90 grams of PP base plastic was mixed with 5 grams of polyoxypropylene glycerol ether and 5 grams of polyethylene glycol stearate as anti-biofouling compounds in a twin-screw extruder to form a masterbatch. The temperature of the twin-screw extruder ranged from 180°C at the front to 210°C at the rear.

[0101] The masterbatch and base plastic were mixed to form the sterile-repellent plastic sample B1. Specifically, the plastic sample B1 was injection molded into the lid of the B1 sample in an injection molding machine at temperatures ranging from 190°C at the front to 225°C at the back. The weight ratio of the base plastic to the masterbatch was 9:1.

[0102] A comparative plastic sample (control) containing only the base plastic (PP) was also prepared in the same manner, except that it included neither the masterbatch nor the anti-biofouling compound.

[0103] Swab tests were performed to compare the bacteria repellency of the bacteria repellent plastic sample (B1) with a comparative plastic sample (control). Table 6 shows the results of the reduction of colony forming units of E. coli and S. aureus on lid samples made of different plastics.

[0104] In addition, two other samples, B2 and B3, were prepared based on polypropylene impact copolymer (PPIC) that incorporated one or more anti-biofouling agents, including polyoxypropylene glycerol ether ("GP-330"), polyoxypropylene (30) glycol (" P188”) and the same or similar ingredients as the anti-biofouling agent used in Sample B1. Other possible anti-biofouling agents include polyoxyethylene 40 hydrogenated castor oil (“ RH40"). If swab testing and other mechanical property tests were performed, sample B2 was manufactured in the form of a bottle cap, while sample B3 was manufactured in the form of a 4 cm x 4 cm sheet. In one embodiment, a masterbatch of PPIC, one or more anti-biofouling agents, and other additives was prepared in a ratio of about 18:1:1, and then the PPIC and masterbatch were injection molded in a ratio of about 9:1 to prepare samples B2 and B3.

[0105] Table 6:

[0106]

[0107]

[0108] As shown in Table 6, the bacteria-repellent plastic (B1) of the present invention reduced E. coli by 98.5% in the swab test compared to the comparative plastic (control). When exposed to Staphylococcus aureus, the bacteria-repellent plastic (B1) of the present invention reduced Staphylococcus aureus by over 99.9% compared to the comparative plastic (control). Samples B2 and B3 also exhibited similar repellency against Staphylococcus aureus as sample B1, though their repellency against E. coli was slightly lower than that of sample B1. These results indicate that PP modified with anti-biofouling compounds exhibits high repellency against both E. coli and Staphylococcus aureus, particularly S. aureus. Furthermore, lids made from the bacteria-repellent plastic B1 passed food contact safety tests according to EU Commission Regulation No. 10 / 2011 (overall migration and heavy metals) and the U.S. Food and Drug Administration's 21 CFR 177.1520 (olefin polymers). Furthermore, the lids passed the LFGB sensory inspection - odor and taste test.

[0109] Test results of tensile strength of sterile polypropylene

[0110] ASTM D638-10 Type VI test specimens of PP and sterile PP were prepared by dumbbell cutter as in Example 1 and tested by MTS at a speed of 10 mm / min.

[0111] Table 7:

[0112]

[0113] According to the results in Table 7, incorporation of 0.56 wt% of polyoxypropylene glycerol ether and poly(ethylene glycol) distearate into PP does not substantially affect the tensile strength of the plastic, which means that the polymer matrix of PP remains intact without the incorporation.

[0114] Impact strength test results of bacteria-repellent PP

[0115] As in Example 1, the Izod impact strength was characterized by a Kunlun impact tester according to ASTM D256-10 with an impact energy of 5.5 J.

[0116] Table 8:

[0117]

[0118] According to the results in Table 8, the incorporation of 0.56 wt% of polyoxypropylene glycerol ether and poly(ethylene glycol) distearate into PP has some positive effects on the impact strength of the plastic (an increase of 9.3% compared to PP without such incorporation), which means that the polymer matrix of PP remains intact in the absence of such doping and the incorporation of anti-biofouling agents can even improve its impact strength.

[0119] Similar to the Izor impact test (according to ASTM D256-10) on sample B1, the same test was performed on sample B2 in the form of a bottle cap, and ordinary PPIC plastic was used as a control group. The results showed that the difference in impact strength between sample B2 and ordinary PPIC (control group) was approximately +9.3% (70.95 kJ / m 3 vs 64.89 kJ / m 3 ).

[0120] The caps made of the bacteria-repellent plastic (B1) were also subjected to tensile strength testing. The tensile strength (according to ASTM D638-10) of the bacteria-repellent plastic B1 was 31.94 MPa, while the comparative plastic control was 32.1 MPa, representing a 0.5% decrease. Furthermore, when comparing the test bacteria-repellent plastic B1 to the control, the impact strength (according to ASTM D256-10) showed an 8.5% increase.

[0121] Example 3 - Bacteria-repellent silicone rubber

[0122] A bacteriostatic silicone rubber (C1) was prepared by mixing 100 grams of silicone rubber, 1.07 grams of poly(ethylene glycol) dimethylsiloxane anti-biofouling compound, and 0.13 grams of fumed silica on a rubber mixer. Preparation of the bacteriostatic silicone sheet samples involved both vulcanization and post-vulcanization. The former step (vulcanization) was accomplished by compression molding at 180°C for 200 seconds, while the latter step (post-vulcanization) was achieved by treating the compressed samples in an oven at 200°C for at least four hours in the presence of an inorganic filler, such as silica.

[0123] In a prior US patent application filed by the same applicant (Publication No. US20200017658), it was concluded that only liquid silicone rubber (LSR) could be modified with certain other anti-biofouling agents to achieve satisfactory bacterial repellency, rather than using poly(ethylene glycol) dimethylsiloxane to modify solid silicone rubber (HCR). In contrast, the present invention was able to modify HCR using the following exemplary anti-biofouling agent, polyethylene glycol 12 (PEG12) dimethylsiloxane ("OFX0193"), such that during processing, the silicone rubber and the anti-biofouling agent could withstand temperatures of 200°C to achieve satisfactory bacterial repellency, while the other mechanical properties of the present invention's anti-biofouling silicone rubber remained substantially unchanged after processing.

[0124] Comparative silicone rubber samples (controls) containing only the base material (silicone rubber) were also prepared in the same manner, except that no filler or anti-biofouling compound was included.

[0125] A swab test (as described above) was performed to compare the repellency of the germ-repellent plastic sample (C1) with a comparative plastic sample (control). Table 9 shows the results of the reduction of colony forming units of E. coli and S. aureus on lid samples made from different plastics.

[0126] In addition to Sample C1, silicone rubber, specifically HCR, was also combined with other anti-biofouling agents that may be compatible with HCR, including trimethoxysilyl propoxy polyethylene glycol oxymethyl ether ("Gelest SIT8408.0") and polyethylene glycol 400 distearate (" PEG 400DS”) to obtain other bacteriostatic silicone rubber samples C2 to C5. These bacteriostatic silicone rubbers were also subjected to swab tests to demonstrate their bacteriostatic properties against Staphylococcus aureus and Escherichia coli.

[0127] Table 9:

[0128]

[0129] As shown in Table 9, all of the bacteriostatic silicone rubber samples (C1 to C5) of the present invention reduced Escherichia coli and Staphylococcus aureus by more than 99.9% in the swab test compared to the comparative sample (control group). Furthermore, sheets made from bacteriostatic silicone rubber C1 passed European Commission Resolution AP(2004) 5 (silicone rubber overall migration), U.S. Food and Drug Administration 21 CFR 177.1210 (closures with sealing gaskets), and French regulations (France Arrete du, November 25, 1992, Annex III No. 2 - Ref. European Pharmacopoeia, 2005; by ICP analysis). Furthermore, bacteriostatic silicone rubber C1 passed the LFGB sensory test - odor and taste test.

[0130] Tensile strength test results of sterile silicone rubber

[0131] ASTM D638-10 Type VI specimens of silicone rubber and antibacterial silicone rubber were prepared by dumbbell cutter as in Example 1 and tested by MTS at a speed of 10 mm / min.

[0132] Table 10:

[0133]

[0134] According to the results in Table 10, the incorporation of 1.07 wt% of poly(ethylene glycol) dimethylsiloxane into silicone does not substantially affect the tensile strength of the plastic, which means that the polymer matrix of silicone remains intact without the incorporation.

[0135] Furthermore, the tensile strength (according to ASTM D638-10) of the sterile silicone rubber C1 was 10.89 MPa, compared to 10.57 MPa for the comparative plastic control, representing an increase of 2.9%.

[0136] Sterile silicone rubber hardness test results

[0137] Shore A hardness is measured using a Phase II PHT-950 digital Shore A durometer according to ASTM D2240-04. A 6.4 mm thick specimen is placed on a hard, flat surface. The durometer's indenter is pressed into the specimen parallel to the specimen surface. The hardness is measured within one second (or as specified by the customer) of firm contact with the specimen.

[0138] Table 11:

[0139]

[0140]

[0141] According to the results of Table 11, the incorporation of 1.07 wt% of poly(ethylene glycol) dimethylsiloxane into silicone does not substantially affect the hardness of the plastic, which means that the polymer matrix of the silicone remains intact without the incorporation.

[0142] Samples C2-C5 were also subjected to the same Shore A hardness test, and the results are summarized as follows:

[0143] Table 12:

[0144] Sample name Shore A hardness C2 44.5 C3 46.1 C4 45.5 C5 50.6

[0145] Overall, the light transmittance, tensile strength, impact strength, and heat deformation temperature of articles made from the food-contact-safe, bacteria-repellent materials of this invention do not vary by more than 10% compared to the corresponding original materials. According to some supplementary evaluation reports, the hardness and tensile strength of sealing rings and nozzles used in drinking bottles do not vary by more than 10% compared to the original materials.

[0146] Industrial Applicability

[0147] The present invention is suitable for containers and processors for food processing, consumption, transportation and storage, which are required to maintain certain mechanical properties while imparting bactericidal properties, and the plastic material does not release harmful components and complies with the relevant regulations of major food contact articles or materials in the world.

Claims

1. A food contact safe bacteria repellent material selected from thermoplastics or elastomeric materials, characterized in that: The materials include: One or more polyols and their derivatives as anti-biofouling agents, accounting for the thermoplastic plastic Or the total weight of the elastomer is 0.1 to 20wt%, wherein the polyol and its derivatives include poly Ethylene glycol sorbitan monooleate, poly(ethylene glycol) sorbitan hexaoleate, and cetearyl stearic acid Ester-20; and Gas treated with hexamethyldisilazane, dimethylpolysiloxane or polydimethylsiloxane Silica or untreated fumed silica as filler, myristyl alcohol palm Acid ester carrier, release agent, curing agent and / or oil component, each one or more of the components accounts for The total weight of the thermoplastic or the elastomeric material is 0.1 to 2 wt%, wherein said one or more anti-biofouling agents form a hydrated layer on said thermoplastic or said elastomer.

2. The material according to claim 1, wherein the thermoplastic is selected from modified polycyclohexane dimethyl terephthalate or polypropylene and one of its copolymers.

3. The material of claim 2, wherein the copolymer of polypropylene comprises a polypropylene impact copolymer.

4. The material of claim 1, wherein the one or more anti-biofouling agents are present in an amount of 0.1% to 10% by weight.

5. The material of claim 1, wherein the filler comprises one or more reinforcing fillers of the nanoscale inorganic particle type. The material according to claim 5 , wherein the content of the inorganic particles is 0.1 to 1% by weight.

7. The material of claim 1, wherein the carrier is represented by the formula: wherein R1 and R2 are independently hydrocarbon moieties and each of said hydrocarbon moieties contains 10 to 30 carbon atoms having a straight or branched chain.

8. The material of claim 1, wherein the myristyl palmitate carrier is present in an amount of 0.1% to 1% by weight.

9. The material of claim 8, wherein the carrier comprises one of stearoyl palmitate, stearoyl behenate, stearyl stearate, palmitoyl palmitate, and myristyl myristate.

10. The material of claim 1, wherein the elastomer is solid silicone rubber.

11. The material of claim 1 , wherein the filler comprises silica.

12. The material according to claim 1, wherein the oil is a silicone oil containing a hydroxyl silicone oil.

13. The material of claim 1, wherein the curing agent comprises one of 2,4-dichlorobenzoyl peroxide and di-t-butyl 1,1,4,4-tetramethyltetramethylene diperoxide.

14. A food contact article comprising the material according to any one of claims 1 to 13.

15. A method for preparing a food contact safe germ repellent material selected from thermoplastics according to claim 1, characterized in that: The method comprises: An anti-biofouling agent masterbatch is prepared by melt mixing the thermoplastic material with 0.1 to 20 wt% of the anti-biofouling agent, one or more fumed silica treated with hexamethyldisilazane, dimethylpolysiloxane and polydimethylsiloxane, a myristyl palmitate carrier, a mold release agent, a curing agent and / or an oil in a twin-screw extrusion process by setting the temperature range of the twin-screw extruder to 180° C. at the front and 210° C. at the rear, wherein each one or more of the components accounts for 0.1 to 2 wt% of the total weight of the thermoplastic; The anti-biofouling agent masterbatch is added into the thermoplastic material at 1% to 25wt% for molding to obtain the food contact safe bacteria repellent material. wherein the anti-biofouling agent comprises polyol and its derivatives, wherein the polyol and its derivatives comprise one of polyethylene glycol sorbitan monooleate, poly(ethylene glycol) sorbitan hexaoleate and cetearyl stearate-20, The thermoplastic material mixed with the anti-biofouling agent is selected from modified polycyclohexane dimethyl terephthalate or polypropylene, and the anti-biofouling agent forms a hydrated layer on the thermoplastic.

16. A method for preparing a food contact safe germ repellent material selected from elastomeric materials according to claim 1, characterized in that: The method comprises: mixing raw silicone rubber, one or more polyols and their derivatives as anti-biofouling agents, an untreated silica filler, and a myristyl palmitate carrier in a rubber mixer to form a mixture; Compression molding the mixture and vulcanizing it to obtain vulcanized silicone rubber; The vulcanized silicone rubber is placed in an oven for post-vulcanization treatment to obtain the food contact safe bacteria-repellent material. wherein the one or more anti-biofouling agents form a hydrated layer on the elastomer.

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