A shea butter oil and antimicrobial modified nitrile latex protective glove and a preparation method thereof

Abstract

This invention discloses a protective glove made of shea butter and an antibacterial agent modified with nitrile latex, and its preparation method. The glove uses carboxylated nitrile latex as the matrix, compounded with a silane coupling agent-modified composite natural oil and a nano-zinc oxide-chitosan composite antibacterial agent, and is prepared through an impregnation and vulcanization process. The product utilizes the synergistic effect of the natural oil and the antibacterial agent, achieving an antibacterial rate of ≥99.9%, while significantly improving the softness, wearing comfort, and aging resistance of nitrile gloves. This solves the problems of traditional nitrile gloves, such as stiffness, short antibacterial duration, and easy aging and cracking after long-term use. The process of this invention is simple and easy to industrialize, and the resulting product is suitable for food processing, household cleaning, and daily protection.

Description

Technical Field

[0001] This invention belongs to the field of polymer material modification and protective product preparation technology, specifically relating to a protective glove made of shea butter and antibacterial agent modified with nitrile latex and its preparation method. Background Technology

[0002] Nitrile latex protective gloves possess excellent oil, acid, and alkali resistance, as well as abrasion resistance, and pose no risk of allergic reactions to natural rubber proteins, making them a mainstream product for daily household protection. However, traditional nitrile gloves have significant technical shortcomings: nitrile latex itself lacks flexibility, resulting in stiff and uncomfortable gloves that are prone to brittleness at low temperatures; the products lack antibacterial properties, making them susceptible to bacterial and mold growth on the surface during food handling and kitchen / bathroom cleaning, leading to cross-contamination; existing antibacterial nitrile gloves often only contain inorganic antibacterial agents, resulting in poor compatibility, easy aggregation and shedding, leading to short-lasting antibacterial effects and reduced glove mechanical properties; furthermore, traditional nitrile gloves are prone to aging and cracking with prolonged use, resulting in a short lifespan.

[0003] Shea butter, a natural plant oil, is rich in unsaturated fatty acids and vitamins, and possesses plasticizing, moisturizing, film-forming, and antioxidant properties. It can be used to modify rubber to improve its flexibility and aging resistance. Nano-zinc oxide and chitosan are respectively highly effective and long-lasting inorganic antibacterial agents and highly compatible natural organic antibacterial agents; their combination can achieve broad-spectrum and environmentally friendly antibacterial properties. Therefore, developing nitrile protective gloves that combine comfort, skin-friendliness, long-lasting antibacterial effects, and excellent mechanical properties has significant market value and application prospects. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a protective glove modified with shea butter and antibacterial agent in nitrile latex and its preparation method. This glove has the characteristics of broad-spectrum antibacterial properties and skin-friendly soothing properties. At the same time, it performs excellently in terms of wearing comfort, mechanical strength, aging resistance and antibacterial durability, and can meet the protection needs of multiple scenarios such as food processing, household cleaning and daily protection.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A protective glove made from shea butter and an antibacterial agent-modified nitrile latex, the glove being prepared from the following raw materials in parts by weight:

[0007] The mixture comprises 100 parts of carboxylated nitrile butadiene latex, 3-8 parts of modified composite natural oils, 1-5 parts of composite antibacterial agent, 0.5-2 parts of vulcanizing agent, 1-3 parts of vulcanization accelerator, 1-2 parts of vulcanization activator, 0.3-1 parts of stabilizer, 0.2-0.8 parts of thickener, and 20-40 parts of deionized water; wherein the carboxyl content of the carboxylated nitrile butadiene latex is 4-8% by mass; and wherein the modified composite natural oil is composed of shea butter and tea tree oil or a blend of tea tree oil.

[0008] Optionally, the composite natural oil is pretreated with silane coupling agent KH-550. The pretreatment process is as follows: the composite natural oil is stirred and mixed with 0.5-2.0 wt% KH-550 at 40-50°C for 30-40 minutes to obtain the modified composite natural oil.

[0009] Optionally, the composite antibacterial agent is a compound of nano zinc oxide and chitosan, wherein the nano zinc oxide has a particle size of 15-30 nm, the chitosan has a degree of deacetylation ≥90%, and the mass ratio of nano zinc oxide to chitosan is 3:1-5:1.

[0010] Optionally, the vulcanizing agent is one or two of sulfur and tetramethylthiuram disulfide; the vulcanization accelerator is one or two of sodium dibutyldithiocarbamate and 2-mercaptobenzothiazole; and the vulcanization activator is a mixture of zinc oxide and stearic acid in a mass ratio of 2:1.

[0011] Optionally, the stabilizer is sodium dodecylbenzenesulfonate or polyvinylpyrrolidone; the thickener is hydroxyethyl cellulose or xanthan gum.

[0012] Optionally, the preparation method of the shea butter and antibacterial agent modified nitrile latex protective gloves includes the following specific preparation steps:

[0013] S1. Add nitrile latex to the reactor, heat to 35-45℃, add stabilizer and deionized water and stir for 10-15 minutes to obtain latex base liquid;

[0014] S2. Add the pretreated modified composite natural oil to the latex base liquid and stir at high speed of 800-1000 r / min for 30-40 min; then add the composite antibacterial agent and ultrasonically disperse at 35-45℃ and 300-500W for 20-30 min to obtain the pre-modified latex.

[0015] S3. Add vulcanization activator, vulcanizing agent and vulcanization accelerator to the pre-modified latex in sequence, stir at a low speed of 200-300 r / min for 20-30 min, and finally add thickener to adjust the viscosity to 500-800 mPa·s to obtain modified nitrile latex composition.

[0016] S4. Prepare a calcium chloride aqueous solution with a mass concentration of 15-20% as a coagulant;

[0017] S5. After degreasing, acid washing, alkali washing, water washing, and drying the ceramic hand mold, immerse it in a coagulant for 5-10 seconds and dry it at 80-90℃ for 10-15 minutes.

[0018] S6. Immerse the hand mold in the modified nitrile latex composition for 10-20 seconds, lift and drain for 1-2 minutes, and pre-dry at 70-80℃ for 20-30 minutes to obtain the semi-finished glove.

[0019] S7. Vulcanize the semi-finished gloves at 100-120℃ for 30-40 minutes, chlorinate them with 0.5-1% sodium hypochlorite aqueous solution for 3-5 seconds, wash them with water, filter them, dry them at 80-90℃ for 15-20 minutes, demold them, and roll the edges to obtain the shea butter and antibacterial agent modified nitrile latex protective gloves.

[0020] The beneficial effects of this invention are as follows: The protective gloves prepared by this invention have excellent skin-friendly comfort and anti-aging properties. The modified composite natural oil modified with silane coupling agent has excellent compatibility with nitrile latex, which can significantly improve the flexibility of the gloves, making them soft and non-stiff to wear, while effectively delaying aging and cracking and extending their service life. The gloves of this invention use a nano zinc oxide and chitosan composite system, which has a prominent synergistic antibacterial effect with an antibacterial rate of ≥99.9%. The antibacterial effect is long-lasting and does not easily fall off, and it can inhibit a variety of harmful microorganisms. The gloves have excellent overall mechanical properties, with a tensile strength of 24-30MPa and an elongation at break of 450%-550%, and also have good wear resistance and acid and alkali resistance. The process of this invention is simple, requires no special equipment, has high production efficiency, is environmentally friendly and safe, and is suitable for large-scale industrial production. It can meet the high-performance protection needs of multiple scenarios such as food processing and household cleaning. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0022] Example 1: A protective glove made of shea butter and antibacterial agent modified nitrile latex, the glove is prepared from the following raw materials in parts by weight:

[0023] 100 parts of carboxylated nitrile latex (carboxyl content 4%), 3 parts of modified composite natural oils (shea butter: coconut oil = 4:1), 1 part of composite antibacterial agent (nano zinc oxide: chitosan = 3:1), 0.5 parts of vulcanizing agent (sulfur), 1 part of vulcanization accelerator (sodium dibutyldithiocarbamate), 1 part of vulcanization activator (zinc oxide: stearic acid = 2:1), 0.3 parts of stabilizer (sodium dodecylbenzenesulfonate), 0.2 parts of thickener (hydroxyethyl cellulose), and 20 parts of deionized water;

[0024] This embodiment describes a method for preparing protective gloves made of shea butter and antibacterial agent-modified nitrile latex. The specific preparation steps are as follows:

[0025] S1. Mix shea butter and coconut oil at a mass ratio of 4:1 to obtain a composite natural oil. Add 0.5 wt% of silane coupling agent KH-550 to the composite natural oil and stir at 350 r / min for 30 min at 40℃ to obtain a modified composite natural oil.

[0026] S2. Mix nano zinc oxide (particle size 15nm) and chitosan (degree of deacetylation 90%) at a mass ratio of 3:1, and stir in a high-speed mixer at 1500r / min for 10min to obtain a uniformly dispersed composite antibacterial agent.

[0027] S3. Add carboxylated nitrile latex to the reactor, start stirring at 200 r / min, and heat to 35℃; add sodium dodecylbenzene sulfonate stabilizer and deionized water, and stir at 200 r / min for 10 min to obtain a uniformly dispersed latex base liquid without precipitation.

[0028] S4. Add the above-mentioned modified composite natural oil to the latex base liquid, increase the stirring speed to 800 r / min, and stir at high speed for 30 min to make the oil and latex fully compatible; then add the composite antibacterial agent, stop stirring, and ultrasonically disperse at 35℃ and 300W for 20 min to obtain the pre-modified latex (stirring is turned on for 30s every 5 min during ultrasonication to avoid local agglomeration).

[0029] S5. Turn off the ultrasound and add the vulcanization activator, vulcanizing agent sulfur, and vulcanization accelerator sodium dibutyldithiocarbamate to the pre-modified latex in sequence. Stir at 200 r / min for 20 min. Finally, add the thickener hydroxyethyl cellulose and continue stirring for 5 min. Adjust the viscosity of the system to 500 mPa·s (measured with a rotational viscometer) to obtain a uniform and stable modified nitrile latex composition.

[0030] S6. Weigh 15 parts of calcium chloride and 85 parts of deionized water and mix them. Stir at 300 r / min until completely dissolved to prepare a 15% calcium chloride aqueous solution. Let it stand to remove bubbles and use it as a coagulant for later use.

[0031] S7. Take a clean ceramic hand mold and immerse it in a 5% alkaline degreasing agent (sodium hydroxide aqueous solution) at 40℃ for 10 minutes to remove surface oil stains. Then rinse it three times with running water for 30 seconds each time to remove residual degreasing agent. Place the hand mold in an 80℃ oven to pre-dry for 15 minutes to remove surface moisture. After cooling to room temperature, vertically immerse it in a 15% calcium chloride aqueous solution coagulant for 5 seconds to ensure that the coagulant is evenly adhered to the surface of the hand mold. After slowly lifting it out, place it in an 80℃ oven to dry for 10 minutes to obtain a pre-treated hand mold with a dry surface and a uniformly formed coagulant film.

[0032] S8. Immerse the pretreated hand mold vertically into the modified nitrile latex composition for 10 seconds, slowly pull it up at a speed of 5 cm / s, drain for 1 minute, and pre-dry it in a 70℃ oven for 20 minutes to obtain a semi-finished glove.

[0033] S9. Place the semi-finished gloves along with the hand mold into a vulcanizing oven and vulcanize at 100°C for 30 minutes; chlorinate with 0.5wt% sodium hypochlorite aqueous solution for 3 seconds, rinse thoroughly with water; dry in an 80°C oven for 15 minutes, cool, demold, and roll the edges to obtain the shea butter and antibacterial agent modified nitrile latex protective gloves.

[0034] Example 2: A protective glove made of shea butter and antibacterial agent modified nitrile latex, the glove is prepared from the following raw materials in parts by weight:

[0035] 100 parts of carboxylated nitrile latex (carboxyl content 6%), 5 parts of modified composite natural oils (shea butter: tea tree oil = 4:1), 3 parts of composite antibacterial agent (nano zinc oxide: chitosan = 4:1), 1 part of vulcanizing agent (tetramethylthiuram disulfide), 2 parts of vulcanization accelerator (2-mercaptobenzothiazole), 1 part of vulcanization activator (zinc oxide: stearic acid = 2:1), 0.6 parts of stabilizer (polyvinylpyrrolidone), 0.5 parts of thickener (xanthan gum), and 30 parts of deionized water;

[0036] The preparation method of the protective gloves modified with shea butter and antibacterial agent in this embodiment is the same as that in Example 1.

[0037] Example 3: A protective glove made of shea butter and antibacterial agent modified nitrile latex, the glove is prepared from the following raw materials in parts by weight:

[0038] 100 parts of carboxylated nitrile latex (carboxyl content 8%), 8 parts of modified composite natural oils (shea butter: coconut oil = 4:1), 5 parts of composite antibacterial agent (nano zinc oxide: chitosan = 5:1), 1 part of vulcanizing agent (sulfur), 2 parts of vulcanization accelerator (2-mercaptobenzothiazole: tetramethylthiuram disulfide = 1:1), 1 part of vulcanization activator (zinc oxide: stearic acid = 2:1), 1 part of stabilizer (polyvinylpyrrolidone), 0.8 parts of thickener (xanthan gum), and 40 parts of deionized water;

[0039] The preparation method of the protective gloves modified with shea butter and antibacterial agent in this embodiment is the same as that in Example 1.

[0040] Comparative Example 1: The gloves of this comparative example were prepared from the following parts by weight of raw materials:

[0041] 100 parts carboxylated nitrile latex (carboxyl content 4%), 1 part composite antibacterial agent (nano zinc oxide: chitosan = 3:1), 0.5 parts vulcanizing agent (sulfur), 1 part vulcanization accelerator (sodium dibutyldithiocarbamate), 1 part vulcanization activator (zinc oxide: stearic acid = 2:1), 0.3 parts stabilizer (sodium dodecylbenzenesulfonate), 0.2 parts thickener (hydroxyethyl cellulose), 20 parts deionized water;

[0042] The gloves in this comparative example were prepared using the same method as in Example 1, except that no modified composite natural oils were added.

[0043] Comparative Example 2: The gloves of this comparative example were prepared from the following parts by weight of raw materials:

[0044] 100 parts of carboxylated nitrile latex (carboxyl content 4%), 3 parts of modified composite natural oils (shea butter: coconut oil = 4:1), 0.5 parts of vulcanizing agent (sulfur), 1 part of vulcanization accelerator (sodium dibutyldithiocarbamate), 1 part of vulcanization activator (zinc oxide: stearic acid = 2:1), 0.3 parts of stabilizer (sodium dodecylbenzenesulfonate), 0.2 parts of thickener (hydroxyethyl cellulose), and 20 parts of deionized water;

[0045] The gloves in this comparative example were prepared using the same method as in Example 1, except that no compound antibacterial agent was added.

[0046] Performance testing

[0047] 1. Antibacterial performance test

[0048] The antibacterial performance test was performed according to GB / T 20944.3-2008 standard. The specific steps are as follows: Select glove samples prepared in the embodiments and comparative examples of this invention, cut 50mm×50mm sterile samples, and place them in sterile petri dishes; Activated and cultured Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 6538) bacterial suspensions (concentration adjusted to 1×10⁻⁶) to the logarithmic growth phase were added. 5 -1×10 6 0.2 mL of each bacterial solution (CFU / mL) was evenly added to the sample surface, and a sterile polyethylene film was quickly covered to ensure full contact between the bacterial solution and the sample. The sample was then placed in a constant temperature incubator at 37°C and a relative humidity of over 90% for 24 hours. After incubation, 10 mL of sterile physiological saline was added to each petri dish, and the sample surface was thoroughly shaken to wash away any surviving bacteria. The number of colonies in the eluent was determined using the plate count method. A blank control group (without sample, only bacterial solution added) was also set up. The antibacterial rate of the sample was calculated using the formula: "Antibacterial rate (%) = (Number of colonies in blank control group - Number of colonies in sample group) / Number of colonies in blank control group × 100%".

[0049] Table 1. Test data on antibacterial properties of different samples

[0050] sample Antibacterial rate of Escherichia coli (%) Antibacterial rate against Staphylococcus aureus (%) Example 1 99.91 99.90 Example 2 99.95 99.96 Example 3 99.98 99.99 Comparative Example 1 99.00 98.80 Comparative Example 2 65.20 63.50

[0051] Examples 1-3 of this invention show antibacterial rates of over 99.9% against both *Escherichia coli* and *Staphylococcus aureus*, demonstrating excellent and stable antibacterial effects. Comparative Example 2, lacking the added compound antibacterial agent, exhibited a significantly reduced antibacterial rate to approximately 65%. While Comparative Example 1 still maintained a relatively high antibacterial rate, it was slightly lower than the examples, indicating that the compound antibacterial agent is the core of the antibacterial effect of this invention, and the modified compound natural oil can synergistically enhance its antibacterial stability.

[0052] 2. Mechanical property testing

[0053] Mechanical property testing was performed in accordance with GB / T 528-2009 "Determination of Tensile Stress-Strain Properties of Vulcanized Rubber or Thermoplastic Rubber". The specific steps are as follows: Three dumbbell-shaped Type 1 specimens (effective working length 25mm, width 4mm, thickness measured according to actual samples) were cut from the glove samples prepared in the embodiments and comparative examples of this invention, along the unwrinkled area of ​​the glove palm. Using an electronic universal testing machine, the tensile speed was set to 500mm / min. After standing for 24 hours at room temperature (23℃±2℃) and relative humidity 50%±5%, the specimens were tested. During testing, both ends of the specimen were clamped in the upper and lower fixtures of the testing machine, ensuring that the specimen axis coincided with the center line of the fixture and there was no torsion. The testing machine was started for tensile testing, and the maximum tensile force and gauge length elongation at fracture were recorded. The tensile strength (MPa) was calculated using the formula: Maximum tensile force (N) / Original cross-sectional area of ​​the specimen (mm²). 2 ), Elongation at break (%) = (gauge length at break - original gauge length) / original gauge length × 100%, and take the average of the test results of 3 samples as the final data.

[0054] Table 2 Test data of mechanical properties of different samples

[0055] sample Tensile strength / MPa Elongation at break / % Example 1 24 450 Example 2 26 460 Example 3 25 450 Comparative Example 1 18 380 Comparative Example 2 22 420

[0056] The embodiments of this invention exhibit good mechanical properties, with a tensile strength ≥24MPa and an elongation at break ≥450%, meeting the requirements for protective gloves. Comparative Example 1, without the added modified composite natural oil, shows a significant decrease in mechanical properties, while Comparative Example 2's properties are also slightly lower than the embodiments, indicating that the modified composite natural oil works synergistically with the components to effectively improve the strength and toughness of the latex gloves.

[0057] 3. Hot air aging performance test

[0058] The hot air aging performance was carried out in accordance with GB / T 3512-2014. The dumbbell-shaped specimens of the examples and comparative examples were placed in a hot air aging chamber at (70±2)℃ for 72h of constant temperature aging. After being taken out, they were placed at room temperature for 4h. Then, the tensile strength and elongation at break were measured in accordance with GB / T 528, and the performance retention rate before and after aging was calculated.

[0059] Table 3. Test data of hot air aging performance of different samples

[0060] sample Tensile strength retention rate (%) Elongation at break retention rate (%) Example 1 92 90 Example 2 93 91 Example 3 91 89 Comparative Example 1 78 72 Comparative Example 2 90 88

[0061] The tensile strength and elongation at break of the gloves in the examples retained more than 89% after hot air aging, demonstrating excellent aging resistance. Comparative Example 1, without the addition of modified composite natural oils, showed significantly worse aging performance, indicating that the modified composite natural oils can improve the thermal stability of the latex system, allowing the gloves to maintain good mechanical properties even at high temperatures.

[0062] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A protective glove made of shea butter and an antibacterial agent modified nitrile latex, characterized in that, The gloves are made from the following raw materials in parts by weight: The mixture comprises 100 parts of carboxylated nitrile butadiene latex, 3-8 parts of modified composite natural oils, 1-5 parts of composite antibacterial agent, 0.5-2 parts of vulcanizing agent, 1-3 parts of vulcanization accelerator, 1-2 parts of vulcanization activator, 0.3-1 parts of stabilizer, 0.2-0.8 parts of thickener, and 20-40 parts of deionized water; wherein the carboxyl content of the carboxylated nitrile butadiene latex is 4-8% by mass; and wherein the modified composite natural oil is composed of shea butter and tea tree oil or coconut oil.

2. The protective gloves made of shea butter and antibacterial agent modified nitrile latex according to claim 1, characterized in that, The composite natural oil is pretreated with silane coupling agent KH-550. The pretreatment process is as follows: the composite natural oil is stirred and mixed with 0.5-2.0wt% KH-550 at 40-50℃ for 30-40 minutes to obtain the modified composite natural oil.

3. The protective gloves made of shea butter and antibacterial agent modified nitrile latex according to claim 1, characterized in that, The composite antibacterial agent is a compound of nano zinc oxide and chitosan. The nano zinc oxide has a particle size of 15-30 nm, the chitosan has a degree of deacetylation ≥90%, and the mass ratio of nano zinc oxide to chitosan is 3:1-5:

1.

4. The protective gloves made of shea butter and antibacterial agent modified nitrile latex according to claim 1, characterized in that, The vulcanizing agent is one or two of sulfur and tetramethylthiuram disulfide; the vulcanization accelerator is one or two of sodium dibutyldithiocarbamate and 2-mercaptobenzothiazole; and the vulcanization activator is a mixture of zinc oxide and stearic acid in a mass ratio of 2:

1.

5. The protective gloves made of shea butter and antibacterial agent modified nitrile latex according to claim 1, characterized in that, The stabilizer is sodium dodecylbenzenesulfonate or polyvinylpyrrolidone; the thickener is hydroxyethyl cellulose or xanthan gum.

6. A method for preparing a protective glove modified with shea butter and antibacterial agent using nitrile butadiene latex, used to prepare the protective glove modified with shea butter and antibacterial agent using nitrile butadiene latex as described in any one of claims 1-5, characterized in that, The specific preparation steps are as follows: S1. Add nitrile latex to the reactor, heat to 35-45℃, add stabilizer and deionized water and stir for 10-15 minutes to obtain latex base liquid; S2. Add the pretreated modified composite natural oil to the latex base liquid and stir at high speed of 800-1000 r / min for 30-40 min; then add the composite antibacterial agent and ultrasonically disperse at 35-45℃ and 300-500W for 20-30 min to obtain the pre-modified latex. S3. Add vulcanization activator, vulcanizing agent and vulcanization accelerator to the pre-modified latex in sequence, stir at a low speed of 200-300 r / min for 20-30 min, and finally add thickener to adjust the viscosity to 500-800 mPa·s to obtain modified nitrile latex composition. S4. Prepare a calcium chloride aqueous solution with a mass concentration of 15-20% as a coagulant; S5. After degreasing, acid washing, alkali washing, water washing, and drying the ceramic hand mold, immerse it in a coagulant for 5-10 seconds and dry it at 80-90℃ for 10-15 minutes. S6. Immerse the hand mold in the modified nitrile latex composition for 10-20 seconds, lift and drain for 1-2 minutes, and pre-dry at 70-80℃ for 20-30 minutes to obtain the semi-finished glove. S7. Vulcanize the semi-finished gloves at 100-120℃ for 30-40 minutes, chlorinate them with 0.5-1% sodium hypochlorite aqueous solution for 3-5 seconds, wash them with water, filter them, dry them at 80-90℃ for 15-20 minutes, demold them, and roll the edges to obtain the shea butter and antibacterial agent modified nitrile latex protective gloves.