A nitrile glove without potential cytotoxicity and preparation method thereof

Abstract

The present invention discloses a kind of low cytotoxic nitrile gloves and preparation method, mainly have two aspects of technical improvement, its formula is mainly by changing the vulcanization means (not using sulfur accelerator system) of nitrile gloves, adopt cross-linking agent and zinc oxide to vulcanize acrylonitrile rubber;Technology is realized by increasing weak acid washing before vulcanization, low concentration alcohol solution washing process control section after neutralization and washing etc..The gloves prepared by the present invention, no sulfide bad smell, pinhole rate is low, the gloves 100% sample leachate is 0 grade to L929 cytotoxicity reaction, film thickness is 0.04-0.15mm, tensile strength is greater than 20Mpa, and elongation is 600%-700%.In preparation method of the present invention, vulcanization temperature is relatively low at 90-105 DEG C, compared with traditional commercially available nitrile gloves, and its energy consumption in production process is low.

Description

Technical Field

[0001] The present invention belongs to the technical field of glove preparation, and in particular relates to a nitrile glove without potential cytotoxicity and a preparation method thereof. Background Art

[0002] Currently, surgical gloves primarily include latex gloves, polyisoprene gloves, and polyurethane gloves. Polyurethane and polyisoprene surgical gloves are expensive, and their raw materials are subject to foreign technology monopoly. Latex surgical gloves are also subject to market criticism due to their potential for skin allergies.

[0003] Nitrile gloves are recognized by the public for their low allergy resistance, chemical solvent resistance, and puncture resistance. However, the potential cytotoxicity of commercially available nitrile gloves is too high, which limits their application in surgical gloves and other related fields that require cytotoxicity.

[0004] The present invention aims to provide a nitrile glove without the potential risk of cytotoxicity and a corresponding preparation method, enabling the application of nitrile gloves in surgical gloves and other related fields requiring cytotoxicity. The glove has a high elongation (>600%), a 100% sample extract with a 0-level cytotoxicity response to L929 cells, and a curing temperature of 90°C-105°C, which is 15°C-30°C lower than the conventional curing temperature for nitrile gloves, thus reducing energy consumption in the glove production process. Summary of the Invention

[0005] To address the above issues, the present invention utilizes a crosslinking agent in place of sulfur and an accelerator, which is then added to a nitrile latex containing titanium dioxide, zinc oxide, a surfactant, and a colorant to prepare an aqueous pre-dip. The production process replaces the traditional pre-vulcanization water leaching with a weak acid leaching, and adds an alcohol wash (ethanol-water solution) after the neutralization water wash. This allows for the production of disposable nitrile gloves through precise control of both the formulation and the process.

[0006] The gloves produced by the present invention have no potential cytotoxicity, and the cytotoxicity reaction of 100% sample extract to L929 cells is level 0. The elongation at break is between 600% and 700% (commercially available nitrile gloves are 500% to 600%). The hand feel and wearability are better than those of traditional nitrile gloves. The gloves have no unpleasant odors such as sulfide, have a low pinhole rate, and can be used for medical purposes. The vulcanization temperature of the preparation method is 15°C to 30°C lower than the vulcanization temperature of traditional nitrile gloves.

[0007] The present invention further relates to a technical solution comprising the following steps: first, adding nitrile rubber to an aqueous solution containing potassium hydroxide, then adding a ball mill (titanium dioxide, zinc oxide, surfactant) and a crosslinking agent to the system to prepare a water-based prepreg, which is then pre-vulcanized at room temperature for 24-36 hours. The prepreg is then transferred to a dipping tank for standby use. The nitrile gloves containing no potential cytotoxicity are then produced according to the following process: acid washing, alkali washing, dipping in a coagulant, oven drying, primary dipping, baking, secondary dipping, baking, crimping, weak acid leaching, vulcanization, leaching, chlorine washing, neutralization washing with water, alcohol washing, drying, demoulding, and packaging for storage.

[0008] The present invention prepares nitrile gloves without potential cytotoxicity through a simple and feasible synthesis process, which requires selecting a reasonable ratio of raw materials and performing vulcanization under appropriate temperature conditions.

[0009] (1) Raw materials

[0010] The main raw materials are as follows:

[0011] Nitrile latex: a series of carboxyl nitrile latex with an acrylonitrile content of 27%-35%, such as KNL834 (Kumho latex), KNL830, NL105, etc.

[0012] Cross-linking agent: one or more carbodiimide and polycarbodiimide, such as UN025 (Shanghai Youen Chemical), ZS200 (Guangzhou Zengmao Chemical), SV-02 (Nisshinbo commercial product), V-02 (Nisshinbo commercial product), ZK600 (Shenzhen Zhongke New Materials), ZS600 (Guangzhou Zengmao Chemical) and other commercial products.

[0013] KOH: analytical grade potassium hydroxide.

[0014] Titanium dioxide: rutile titanium dioxide.

[0015] Zinc Oxide: Activated zinc oxide.

[0016] Surfactant: one or a combination of two of alkylbenzene sulfonate (ABS), sodium laurylbenzene sulfonate, sodium alkyl sulfate, polyvinyl alcohol, polyoxyethylene alkylphenol ether, etc.

[0017] Defoaming agent: a combination of one or two of silicone defoaming agent (silicone emulsion), 2-octanol, etc.

[0018] Antioxidant (anti-aging agent): one or a combination of poly (dicyclopentadiene-co-p-cresol), antioxidant D, antioxidant CEA, etc.

[0019] Water: a combination of one or more of softened water, deionized water, and pure water.

[0020] Weak acid: organic weak acid such as acetic acid and citric acid

[0021] Alcohol wash solution: ethanol in water

[0022] (2) Prepreg formula (the formula is the weight after solid conversion, for example, latex usually has a solid content of 42-45%, and 100 parts by weight in the formula is 100 parts by weight of nitrile latex after drying)

[0023] Nitrile latex: 100 parts

[0024] Cross-linking agent: 0.5-2.0 parts

[0025] KOH: 0.5 to 1.5 parts

[0026] Zinc oxide: 0.3-0.8 parts

[0027] Titanium dioxide: 0-1.2 parts

[0028] Surfactant: 0.2-0.5 parts

[0029] Defoaming agent: 0.005-0.03 parts

[0030] Antioxidant (antiaging agent): 0.1-0.5 parts

[0031] Water: 400-600 parts

[0032] (3) Weak acid leaching formula

[0033] The weak acid leaching liquid is a 0.05%-0.5% acetic acid aqueous solution.

[0034] (4) Alcohol lotion formula

[0035] Alcohol wash solution is 3%-10% ethanol water solution

[0036] (5) Water-soluble prepreg production process

[0037] Add titanium dioxide, zinc oxide, antioxidant, and surfactant to a ball mill according to the recipe. Add water (soft water or deionized water) and ball mill for 3 hours. Then, remove the ball mill material and bake it for use. Add water (soft water or deionized water) and potassium hydroxide to the mixing kettle according to the recipe. Add nitrile latex while stirring. After stirring for 0.5 hours, add the crosslinker and the ball mill material calculated according to the recipe. Add the defoamer and set aside. After pre-curing for 24 hours, it can be introduced into the dipping tank at any time.

[0038] (6) Production process of nitrile gloves without potential cytotoxicity

[0039] The molding process of low cytotoxic nitrile gloves: acid washing, water washing, alkali washing, water washing, dipping in coagulant, drying, primary dipping, baking, secondary dipping, baking, curling, weak acid leaching, vulcanization, leaching, chlorine washing, neutralization water washing, alcohol washing, drying, demoulding, packaging and warehousing.

[0040] Specifically, the nitrile gloves with no potential cytotoxicity are produced according to the following process: acid washing, water washing, alkali washing, water washing, dipping in coagulant (10±5s), drying (90±15℃, 10±2s), one-time dipping (15±5s), baking (90±15℃, 5±4min), two-time dipping (12±5s), baking (90±15℃, 5±4min), curling, weak acid leaching (8±5s), vulcanization (90-105℃, vulcanization time 20±5min), leaching, chlorine washing, neutralization water washing, alcohol washing (9±5s), drying, and demolding to obtain nitrile gloves with no potential cytotoxicity.

[0041] The present invention also includes gloves prepared by the above method for preparing nitrile gloves without potential cytotoxicity.

[0042] The glove membrane has a thickness of 0.04-0.15 mm and a tensile strength greater than 20 MPa. For gloves of the same weight, its elongation at break is greater than 600%, surpassing the 500% elongation of traditional nitrile gloves. The potential cytotoxicity is also zero.

[0043] The technical solution of the present invention has the following advantages:

[0044] 1. The gloves have no potential cytotoxicity, and the cytotoxicity reaction of 100% sample extract to L929 cells is level 0.

[0045] 2. The elongation is higher than that of traditional nitrile gloves, reaching more than 600% (the elongation of traditional nitrile gloves is 500%).

[0046] 3. The product has a good feel, no bad sulfide odor, and is more comfortable to wear and lasts longer than traditional nitrile gloves. It also has a low pinhole rate and can be used for medical purposes.

[0047] 4. The vulcanization temperature is 90℃-105℃, which is 15-30℃ lower than the vulcanization temperature of traditional nitrile gloves, and the process is energy-saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative work.

[0049] Figure 1 The present invention is a flowchart of an embodiment of the dipping molding process of nitrile gloves without potential cytotoxicity. DETAILED DESCRIPTION

[0050] The following will clearly and completely describe the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the experimental examples described are only some of the experimental examples of the present invention, not all of the experimental examples. Based on the experimental examples in the present invention, all other experimental examples obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0051] Example 1

[0052] A method for preparing nitrile gloves without potential cytotoxicity comprises the following steps:

[0053] Titanium dioxide (1.0 part), zinc oxide (0.7 part), antioxidant poly (dicyclopentadiene-co-p-cresol) (0.3 part) and surfactant ABS (0.2 part) were added to a ball mill according to the amount indicated in the formula, 1 part of deionized water was added and ball milled for 3 hours, and then the ball mill was discharged for use. In a mixing kettle, 400 parts of deionized water and 0.8 parts of potassium hydroxide were added according to the formula, and nitrile latex Kumho KNL 834 (100 parts) was added under stirring. After stirring for 0.5 hours, a crosslinking agent crosslinked carbodiimide ZK600 (1.5 parts) and ball mill were added thereto, and 0.01 parts of defoaming agent silicone defoamer GX-II (Zhengzhou Jingyuan) was added and pre-cured for 24 hours before being introduced into a dipping tank.

[0054] Then, nitrile gloves with no potential cytotoxicity were produced according to the following process: acid washing, water washing, alkali washing, water washing, dipping in coagulant (5s), drying (80℃, 10s), one dipping in glue (11s), baking (90℃, 2min), two dipping in glue (8s), baking (90℃, 2min), curling, weak acid leaching (0.05% acetic acid, 8s), vulcanization (105℃, vulcanization time 20min), leaching, chlorine washing, neutralization water washing, alcohol washing (5% ethanol, 7s), drying, and demolding to obtain nitrile gloves with no potential cytotoxicity.

[0055] Comparative Example 1: Process Control: The weak acid leaching is restored to the conventional water leaching of butyronitrile, and the alcohol washing step is removed; its production includes the following steps:

[0056] Titanium dioxide (1.0 part), zinc oxide (0.7 part), antioxidant poly (dicyclopentadiene-co-p-cresol) (0.3 part) and surfactant ABS (0.2 part) were added to a ball mill according to the amount indicated in the formula, 1 part of deionized water was added and ball milled for 3 hours, and then the ball mill was discharged for use. In a mixing kettle, 400 parts of deionized water and 0.8 parts of potassium hydroxide were added according to the formula, and nitrile latex Kumho KNL 834 (100 parts) was added under stirring. After stirring for 0.5 hours, a crosslinking agent crosslinked carbodiimide ZK600 (1.5 parts) and ball mill were added thereto, and 0.01 parts of defoaming agent silicone defoamer GX-II (Zhengzhou Jingyuan) was added and pre-cured for 24 hours before being introduced into a dipping tank.

[0057] Then, the nitrile gloves of Comparative Example 1 were produced according to the following process: acid washing, water washing, alkali washing, water washing, dipping in a coagulant (5s), drying (80°C, 10s), primary dipping (11s), baking (90°C, 2min), secondary dipping (8s), baking (90°C, 2min), curling, water leaching (8s), vulcanization (105°C, vulcanization time 20min), leaching, chlorine washing, neutralization and water washing, drying, and demolding to obtain the nitrile gloves of Comparative Example 1.

[0058] Comparative Example 2: Prepreg: Sulfur accelerator replaces crosslinking agent; process control includes weak acid washing and alcohol washing; its production includes the following steps:

[0059] Titanium dioxide (1.0 part), zinc oxide (0.7 part), antioxidant poly (dicyclopentadiene-co-p-cresol) (0.3 part), sulfur (1.0 part), accelerator BZ (0.7) and surfactant ABS (0.2 part) were added to a ball mill according to the amount indicated in the formula, 1 part of deionized water was added and ball milled for 3 hours, and then the ball mill material was discharged for use. In a mixing kettle, 400 parts of deionized water and 0.8 parts of potassium hydroxide were added according to the formula, and nitrile latex Kumho KNL 834 (100 parts) was added under stirring. After stirring for 0.5 hours, the ball mill material was added thereto, and 0.01 parts of defoaming agent silicone defoamer GX-II (Zhengzhou Jingyuan) was added and pre-cured for 24 hours before being introduced into the dipping tank.

[0060] Then, the nitrile gloves of Comparative Example 2 were produced according to the following process: acid washing, water washing, alkali washing, water washing, dipping in a coagulant (5s), drying (80°C, 10s), primary dipping (11s), baking (90°C, 2min), secondary dipping (8s), baking (90°C, 2min), curling, weak acid leaching (0.05% acetic acid, 8s), vulcanization (105°C, vulcanization time 20min), leaching, chlorine washing, neutralization water washing, alcohol washing (5% ethanol, 7s), drying, and demolding to obtain the nitrile gloves of Comparative Example 2.

[0061] Comparative Example 3: Prepreg: Sulfur accelerator replaces crosslinking agent, process control restores water leaching of conventional nitrile, removes alcohol wash, and its production includes the following steps:

[0062] Titanium dioxide (1.0 part), zinc oxide (0.7 part), antioxidant poly (dicyclopentadiene-co-p-cresol) (0.3 part), sulfur (1.0 part), accelerator BZ (0.7) and surfactant ABS (0.2 part) were added to a ball mill according to the amount indicated in the formula, 1 part of deionized water was added and ball milled for 3 hours, and then the ball mill material was discharged for use. In a mixing kettle, 400 parts of deionized water and 0.8 parts of potassium hydroxide were added according to the formula, and nitrile latex Kumho KNL 834 (100 parts) was added under stirring. After stirring for 0.5 hours, the ball mill material was added thereto, and 0.01 parts of defoaming agent silicone defoamer GX-II (Zhengzhou Jingyuan) was added and pre-cured for 24 hours before being introduced into the dipping tank.

[0063] Then, the nitrile gloves of Comparative Example 3 were produced according to the following process: acid washing, water washing, alkali washing, water washing, dipping in a coagulant (5s), drying (80°C, 10s), primary dipping (11s), baking (90°C, 2min), secondary dipping (8s), baking (90°C, 2min), curling, water leaching (8s), vulcanization (105°C, vulcanization time 20min), leaching, chlorine washing, neutralization and water washing, drying, and demolding to obtain the nitrile gloves of Comparative Example 3.

[0064] Comparative Example 4: Prepreg: Sulfur accelerator replaces crosslinking agent, process control restores water leaching of conventional nitrile, removes alcohol washing, and vulcanization temperature restores conventional vulcanization temperature of 120°C. Its production includes the following steps:

[0065] Titanium dioxide (1.0 part), zinc oxide (0.7 part), antioxidant poly (dicyclopentadiene-co-p-cresol) (0.3 part), sulfur (1.0 part), accelerator BZ (0.7) and surfactant ABS (0.2 part) were added to a ball mill according to the amount indicated in the formula, 1 part of deionized water was added and ball milled for 3 hours, and then the ball milled material was discharged for use. In a mixing kettle, 400 parts of deionized water and 0.8 parts of potassium hydroxide were added according to the formula, and nitrile latex KNL 834 (100 parts) was added under stirring. After stirring for 0.5 hours, the ball milled material was added thereto, and 0.01 parts of defoaming agent silicone defoamer GX-II (Zhengzhou Jingyuan) was added and pre-cured for 24 hours before being introduced into a dipping tank.

[0066] Then, the nitrile gloves of Comparative Example 4 were produced according to the following process: acid washing, water washing, alkali washing, water washing, dipping in a coagulant (5s), drying (80°C, 10s), primary dipping (11s), baking (90°C, 2min), secondary dipping (8s), baking (90°C, 2min), curling, water leaching (8s), vulcanization (120°C, vulcanization time 20min), leaching, chlorine washing, neutralization and water washing, drying, and demolding to obtain the nitrile gloves of Comparative Example 4.

[0067] Table 1 Membrane performance test

[0068]

[0069] Table 2 Wearability evaluation

[0070]

[0071] As can be seen from the table above, the 100% sample extract of the nitrile gloves produced by the present invention, which are non-potentially cytotoxic, showed a cytotoxicity level of 0 for L929 cells, and its elongation was higher than that of the comparative example and conventional nitrile gloves. Comparisons between Example 1 and Comparative Example 1, and between Comparative Example 2 and Comparative Example 3, demonstrate that weak acid leaching and alcohol washing processes are effective in reducing cytotoxicity. Comparisons between Example 1 and Comparative Example 2, and between Comparative Example 1 and Comparative Example 3, demonstrate that the crosslinking agent system is less cytotoxic than the sulfur accelerator system.

[0072] Furthermore, the gloves also outlasted conventional nitrile gloves in alcohol and artificial sweat tests, indirectly demonstrating improved wearability during both alcohol disinfection and wear (affected by perspiration). Furthermore, the process avoids the use of sulfur and accelerators, resulting in gloves free of unpleasant sulfide odor.

[0073] A comparison of Example 1 and Comparative Example 1 in Table 2 demonstrates that acid and alcohol washing slightly decreases glove strength, increases elongation, and generally improves donning performance compared to the conventional nitrile glove in Comparative Example 4. Compared to Comparative Example 4, the change in process temperature (baking at 105°C for Comparative Example 3 and 120°C for Comparative Example 4) significantly impacts mechanical properties. Currently, the nitrile glove in Comparative Example 4 is the predominant product on the market.

[0074] Obviously, the above experimental examples are merely illustrative examples for clarity of explanation and are not intended to limit the embodiments. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all embodiments here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for preparing nitrile gloves, characterized in that: The vulcanization of nitrile rubber uses a crosslinking agent and zinc oxide in combination, wherein the crosslinking agent is polycarbodiimide or carbodiimide. The nitrile glove forming process includes a weak acid leaching step before vulcanization and an alcohol washing step added after neutralization and water washing, wherein the weak acid is a citric acid or acetic acid solution with a concentration of 0.05% to 0.5% in aqueous solution, and in the alcohol washing step, the alcohol washing liquid is an ethanol aqueous solution with a concentration of 3% to 10%.

2. The preparation method according to claim 1, characterized in that: The ratio of the prepreg of the nitrile gloves is nitrile latex: cross-linking agent: KOH: zinc oxide: titanium dioxide: surfactant: defoaming agent: antioxidant: water = 100: 0.5-2.0: 0.5-1.5: 0.3-0.8: 0-1.2: 0.2-0.5: 0.005-0.03: 0.1-0.5: 400-600.

3. The preparation method according to claim 1, characterized in that: It also includes a vulcanization process, with a vulcanization temperature of 90 to 115°C and a vulcanization time of 20±5 minutes.

4. The gloves prepared by the preparation method according to any one of claims 1 to 3.

5. The glove according to claim 4, wherein: The film thickness is 0.04-0.15 mm, the tensile strength is greater than 20 MPa, the elongation is between 600-700%, and the cytotoxicity reaction of 100% sample extract of the glove to L929 cells is level 0.

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