Super-soft butyronitrile medical surgical glove and preparation method thereof

Abstract

The invention provides super-soft butyronitrile medical surgical gloves and a preparation method thereof. The super-soft butyronitrile medical surgical gloves are prepared from butyronitrile polyurethane mixed emulsion, styrene-butadiene latex and short-chain organic modified polysiloxane. The flexible network structure is formed by utilizing the flexibility of the short-chain organic modified polysiloxane and the butyronitrile latex with the double-bond structure, and the flexible network structure can absorb external stress and reduce crack propagation, so that the flexibility of the butyronitrile medical gloves is improved. Besides, the short-chain organic modified polysiloxane has lower surface tension and can reduce the surface tension of the nitrile rubber, so that the nitrile rubber is easier to spread and wet when being in contact with other materials, and the requirements of the medical gloves on products are met.

Description

Technical Field

[0001] The present invention relates to the technical field of medical surgical gloves, and in particular to a super-soft nitrile medical surgical glove and a preparation method thereof. Background Art

[0002] Due to their excellent touch and sensitivity, natural latex gloves enable users to perceive subtle tactile sensations and hand movements, making them very suitable for tasks that require a high degree of accuracy and fine manipulation, such as surgery and laboratory research. However, natural latex may cause latex protein allergy. Compared with natural latex gloves, traditional nitrile gloves are slightly inferior in terms of elasticity and fit, and there is a slight lack of wearing comfort. Summary of the Invention

[0003] The purpose of the present invention is to provide a super-soft nitrile medical surgical glove and a preparation method thereof to solve the above technical problems existing in the prior art.

[0004] To solve the above technical problems, a latex provided by the present invention includes a nitrile-polyurethane mixed emulsion, a styrene-butadiene latex, and a short-chain organically modified polysiloxane, wherein the nitrile-polyurethane mixed emulsion is prepared by mixing a carboxylated nitrile latex and an aqueous polyurethane emulsion.

[0005] Further, by weight, the latex includes 88-96 parts of the nitrile-polyurethane mixed emulsion, 1-10 parts of the styrene-butadiene latex, and 0.1-0.5 parts of the short-chain organically modified polysiloxane; It is prepared by mixing the nitrile-polyurethane mixed emulsion, the styrene-butadiene latex, and the short-chain organically modified polysiloxane and stirring at 20-40 °C for 4-6 hours.

[0006] Further, by weight, the nitrile-polyurethane mixed emulsion is prepared by mixing 85-97 parts of the carboxylated nitrile latex and 3-15 parts of the aqueous polyurethane emulsion and stirring at 35-45 °C for 2-4 h.

[0007] Further, the preparation method of the carboxylated nitrile latex is as follows: By weight, take the carboxylated nitrile latex, add a stabilizer, and then sequentially add an antioxidant, sulfur, an activator, and an accelerator, and then perform room-temperature vulcanization for 14-18 hours to obtain the carboxylated nitrile latex.

[0008] Further, the preparation method of the carboxylated nitrile latex is as follows: By weight, take 88-96 parts of the carboxylated nitrile latex, add KOH to adjust the pH to 9-10, and then sequentially add 1.0-3.0 parts of an antioxidant, 0.6-1.6 parts of sulfur, 0.6-2 parts of an activator, and 0.8-1.5 parts of an accelerator, and then perform room-temperature vulcanization for 14-18 hours to obtain the carboxylated nitrile latex.

[0009] Further, the carboxylated nitrile latex is one or both of LG Chem's nitrile latex NL125 and Kumho's nitrile 823 latex; The stabilizer is one or both of ammonia water (NH3•H2O) and KOH; The accelerator is at least one or more of tetramethylthiuram disulfide (TMTD), zinc dibutyldithiocarbamate (ZDBC), and zinc diethyldithiocarbamate (ZDC); The antioxidant is at least one or more of antioxidant 616 (the butylated product of cresol and dicyclopentadiene), antioxidant BHT (2,6-di-tert-butyl-4-methylphenol), and antioxidant 264 (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]); The activator is one or both of ZnO and zinc carbonate (ZnCO3).

[0010] A super-soft nitrile medical surgical glove is prepared from any one of the above-mentioned latexes.

[0011] A method for preparing a super-soft nitrile medical surgical glove, the preparation steps of which include: S1: Clean the mold and dry the cleaned mold; S2: Immerse the dried mold in a coagulant for 1 - 10 seconds; dry the mold with the attached coagulant at a low temperature; S3: Immerse it in the mixed latex of the super-soft nitrile medical surgical glove for 8 - 11 seconds, take out the mold with the attached latex, place the mold with the attached latex in a blast drying oven, and dry it by blowing for 1 - 6 minutes at a temperature of 90 - 130°C; S4: Immerse the semi-dried hand mold in hot water for 10 - 30 seconds; take out the mold that has entered the hot water and dry it, then immerse the mold in a release agent, then take it out and dry and vulcanize it, and then demold it to obtain the super-soft nitrile medical surgical glove.

[0012] Preferably, in step S2: Immerse the dried mold in a coagulant at a temperature of 40 - 45°C for 3 - 5 seconds; dry the mold with the attached coagulant at a low temperature of 83°C ± 2; Preferably, in step S3: Immerse it in the mixed latex of the super-soft nitrile medical surgical glove at a temperature of normal temperature 25 - 28°C for 8 - 11 seconds, take out the mold with the attached latex, place the mold with the attached latex in a blast drying oven, and dry it by blowing for 2 - 4 minutes at a temperature of 100 - 115°C; Preferably, in step S4: dip the incompletely dried hand mold into hot water at a temperature of 75 - 85 °C for 15 - 20 seconds; take out the mold that has entered the hot water and dry it, then immerse the mold in the release agent for 10 seconds, and then take it out and dry and vulcanize it. The vulcanization drying temperature is 115 °C and the time is 15 min, and then demold to obtain super soft nitrile medical surgical gloves.

[0013] Further, the coagulant in step S2 includes: Wetting agent 30 - 40 Kg Calcium nitrate 250 - 350 Kg Wetting agent 3 - 8 Kg Calcium stearate 10 - 30 Kg Soft water 600 - 700 Kg; Weigh soft water, and in a stirred state, add calcium nitrate, calcium stearate, and wetting agent in sequence by means of water bath heating until all solid substances are completely dissolved, and then filter for standby.

[0014] Preferably, the coagulant in step S2 includes: Wetting agent 35 Kg Calcium nitrate 300 Kg Wetting agent 6 Kg Calcium stearate 20 Kg Soft water 639 Kg Weigh 639 Kg of soft water, and in a stirred state (temperature: 45 ± 2 °C), add 300 Kg of solid calcium nitrate, 20 Kg of calcium stearate, and 6 Kg of wetting agent (model: TERIC® 324) in sequence by means of water bath heating until all solid substances are completely dissolved, and then filter for standby.

[0015] Further, the release agent is a polyurethane coating liquid, and the polyurethane coating liquid adopts SX - 643F produced by Shixiu New Material Technology (Zhejiang) Co., Ltd.

[0016] Adopting the above technical solution, the present invention has the following beneficial effects: (1) Introduce an aqueous polyurethane emulsion into the vulcanized carboxyl nitrile latex, and stir at 38 ± 2 °C for 2 - 4 hours to make some double - bond functional groups in the nitrile latex react chemically with the isocyanate groups (-NCO) or amine groups in the aqueous polyurethane to form a cross - linked structure and obtain a mixed latex solution suitable for preparing medical surgical gloves (the mechanical properties fully meet the performance index requirements of ASTM D3577 Class II synthetic latex medical gloves in the US standard).

[0017] (2) By utilizing the structural complementarity and polarity difference between styrene-butadiene latex and nitrile latex, simple hydrogen bonding or van der Waals forces can occur between them, enabling styrene-butadiene latex to not only change its flexibility and plasticity in the system but also meet the stringent requirements for the surface quality of nitrile medical surgical gloves (no obvious defects such as orange peel phenomenon, pinholes, etc.).

[0018] (3) A flexible network structure is formed by using the flexibility of short-chain organically modified polysiloxane and a mixed emulsion of nitrile polyurethane with a double-bond structure. This flexible network structure can absorb external stress and reduce crack propagation, thereby improving the flexibility of nitrile medical gloves. By virtue of the low surface tension of short-chain organically modified polysiloxane, it can reduce the surface tension of nitrile rubber, making it easier to spread and wet when contacting other materials, thus meeting the product requirements for preparing medical gloves without apparent defects (such as orange peel phenomenon, pinholes, etc.). BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 It is a glove product diagram prepared in Example 1 of the present invention; Figure 2 It is a glove product diagram prepared in Comparative Examples 1-3 of the present invention; Figure 3 It is a glove product diagram prepared in Comparative Examples 1-4 of the present invention; Figure 4 It is a glove product diagram prepared in Comparative Examples 1-6 of the present invention; DETAILED DESCRIPTION OF THE EMBODIMENTS The following will clearly and completely describe the technical solutions of the present invention in conjunction with the drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0021] The following further explains the present invention in conjunction with specific embodiments.

[0022] Short-chain organically modified polysiloxane: Evonik Polymer GmbH, model AFCONA-3585; (I) Embodiment Example 1 In this embodiment, a preparation method of a super-soft nitrile medical surgical glove and its preparation method are provided. The specific preparation steps are as follows: Step 1) Preparation method of vulcanized carboxylated nitrile latex 90 Kg of Kumho nitrile 838 latex 1.0 Kg of KOH (5%) 1.0 Kg of antioxidant (KY-616) 0.8 Kg of sulfur (S) 0.8 Kg of ZnO 1.0 Kg of ZDC Take 90 Kg of Kumho nitrile 838 latex, add 1 Kg of KOH (5%) to adjust the pH to 9 - 10, and then sequentially add 1.0 Kg of antioxidant (KY-616), 0.8 Kg of S, 0.8 Kg of ZnO, and 1.0 Kg of ZDC, and then vulcanize at room temperature for 14 hours to obtain vulcanized carboxylated nitrile latex for standby.

[0023] Step 2) Preparation method of nitrile-polyurethane mixed emulsion 88 Kg of vulcanized carboxylated nitrile latex Covestro polyurethane: DLN-SD 12 Kg Weigh 88 Kg of vulcanized carboxylated nitrile latex, and then add Covestro (model: DLN-SD) aqueous polyurethane emulsion. Stir at a temperature of 38 ± 2 °C for 3 h so that some double bond functional groups in the nitrile latex react chemically with the isocyanate groups (-NCO) or amine groups in the aqueous polyurethane to form a cross-linked structure and obtain a uniformly mixed nitrile-polyurethane mixed emulsion suitable for preparing medical gloves for standby.

[0024] Step 3) Preparation method of super-soft nitrile medical surgical glove mixed latex 94.8 Kg of nitrile-polyurethane mixed emulsion 5 Kg of styrene-butadiene latex 0.2 Kg of short-chain organically modified polysiloxane Weigh 94.8 Kg of nitrile-polyurethane mixed emulsion, then weigh 5 Kg of styrene-butadiene latex and stir at room temperature for 35 min, and then add 0.2 Kg of short-chain organically modified polysiloxane (Evonik Polymer GmbH, model AFCONA-3585). The short-chain organically modified polysiloxane is diluted and stirred evenly with 10 times of softened water, and stirred at room temperature for 5 hours to obtain a uniformly dispersed mixed latex suitable for preparing super-soft nitrile medical gloves.

[0025] Step 4) Preparation method of super-soft nitrile medical surgical glove, and its preparation steps include: S1: Clean the mold and dry the cleaned mold; S2: Immerse the dried mold in a coagulant at a temperature of 45°C for 5 seconds; dry the mold with the attached coagulant at a low temperature (83°C ± 2). S3: Immerse it in a super-soft nitrile medical surgical glove mixed latex at a normal temperature of 25 - 28°C for 10 seconds. Take out the mold with the attached latex and place it in a forced-air drying oven. Dry it with forced air at a temperature of 110°C for 3 minutes. S4: Immerse the not fully dried hand mold in hot water at a temperature of 80°C for 18 seconds; take out the mold that has entered the hot water and dry it. Then immerse the mold in a release agent for 10 seconds, and then take it out and dry and vulcanize it. The vulcanization drying temperature is 115°C and the time is 15 min, and then demold to obtain a super-soft nitrile medical surgical glove. Among them, the coagulant in step S2 includes: Wetting agent 35 Kg Calcium nitrate 300 Kg Wetting agent 6 Kg Calcium stearate 20 Kg Soft water 639 Kg Weigh 639 kg of soft water, heat it by water bath to a temperature of 45 ± 2°C, and under stirring, add 300 Kg of solid calcium nitrate, 20 Kg of calcium stearate, and 6 Kg of wetting agent (model: TERIC® 324) in sequence. Keep stirring until all solid substances are completely dissolved, and filter for standby. The release agent in step S4 is a polyurethane coating, and the polyurethane coating uses SX-643F produced by Shixiu New Materials Technology (Zhejiang) Co., Ltd.

[0026] Comparative Example 1-1 The difference from Example 1 is that steps 2) and 3) are missing, and the carboxylated nitrile latex prepared in step 1) is directly used to prepare nitrile latex gloves through step 4).

[0027] Comparative Example 1-2 The difference from Example 1 is that step 1) is missing, and the carboxylated nitrile latex in step 2) is replaced with Kumho Nitrile 838 latex, specifically as follows: Preparation method of nitrile polyurethane mixed emulsion in step 2) Kumho Nitrile 838 latex 88 Kg Covestro polyurethane: DLN-SD 12 Kg Weigh 88 Kg of carboxylated nitrile latex, and then add the aqueous polyurethane emulsion of Covestro (model: DLN-SD). Stir at a temperature of 38 ± 2 °C for 3 h to cause some double bond functional groups in the nitrile latex to chemically react with the isocyanate groups (-NCO) or amine groups in the aqueous polyurethane, forming a cross-linked structure and obtaining a uniformly mixed nitrile-polyurethane mixed emulsion suitable for the preparation of medical gloves for standby.

[0028] Comparative Examples 1-3 The difference from Example 1 lies in that only Step 3) is different, specifically as follows: Step 3) Preparation method of the mixed latex for ultra-soft nitrile medical surgical gloves 94.8 Kg of nitrile-polyurethane mixed emulsion 5 Kg of styrene-butadiene latex Weigh 94.8 Kg of nitrile-polyurethane mixed emulsion, and then weigh 5 Kg of styrene-butadiene latex and stir at room temperature for 30 - 40 min to obtain a uniformly dispersed mixed latex suitable for the preparation of ultra-soft nitrile medical gloves.

[0029] Comparative Examples 1-4 The difference from Example 1 lies in that only Step 3) is different, specifically as follows: Step 3) Preparation method of the mixed latex for ultra-soft nitrile medical surgical gloves 94.8 Kg of nitrile-polyurethane mixed emulsion 0.2 Kg of short-chain organically modified polysiloxane Weigh 94.8 Kg of nitrile-polyurethane mixed emulsion, and then add 0.2 Kg of short-chain organically modified polysiloxane (dilute and stir evenly with 10 times of softened water), and stir at room temperature for 4 - 6 hours to obtain a uniformly dispersed mixed latex suitable for the preparation of ultra-soft nitrile medical gloves.

[0030] Comparative Examples 1-5 The difference from Example 1 is that Steps 1) and 2) are missing, and Step 3) is different. Among them, Step 3) is specifically as follows: Step 3) Preparation method of the mixed latex for ultra-soft nitrile medical surgical gloves Covestro polyurethane: DLN-SD 94.8 Kg 5 Kg of styrene-butadiene latex 0.2 Kg of short-chain organically modified polysiloxane Weigh 94.8 Kg of Covestro polyurethane, then weigh 5 Kg of styrene-butadiene latex and stir at room temperature for 30 - 40 min, and then add 0.2 Kg of short-chain organically modified polysiloxane (dilute and stir evenly with 10 times of softened water), and stir at room temperature for 4 - 6 hours to obtain a uniformly dispersed mixed latex suitable for the preparation of ultra-soft nitrile medical gloves.

[0031] Comparative Examples 1 - 6 The difference from Example 1 is that step 2) is missing, and the carboxylated nitrile latex prepared in step 1) is directly used to replace the nitrile polyurethane mixed latex in step 3).

[0032] Example 2 In this example, a preparation method of a super-soft nitrile medical surgical glove and its preparation method are provided. The specific preparation steps are as follows: Step 1) Preparation method of carboxylated nitrile latex 95 Kg of Kumho nitrile 838 latex 1.2 Kg of KOH (5%) 2.0 Kg of antioxidant (KY-616) 1.2 Kg of sulfur (S) 1.2 Kg of ZnO 1.2 Kg of ZDC Take 95 Kg of Kumho nitrile 838, add 1.2 Kg of KOH (5%) to adjust the pH to 9 - 10, then sequentially add 2.0 Kg of antioxidant (KY-616), 1.2 Kg of S, 1.2 Kg of ZnO, and 1.2 Kg of ZDC, and then vulcanize at room temperature for 16 hours to obtain carboxylated nitrile latex for standby.

[0033] Step 2) Preparation method of nitrile polyurethane mixed latex 90 Kg of carboxylated nitrile latex Covestro polyurethane: DLN-SD 10 Kg Weigh 90 Kg of carboxylated nitrile latex, then add 10 Kg of Covestro (model: DLN-SD) aqueous polyurethane emulsion, and stir at a temperature of 38 ± 2 °C for 3 h to cause some double bond functional groups in the nitrile latex to chemically react with the isocyanate groups (-NCO) or amine groups in the aqueous polyurethane to form a cross-linked structure and obtain a uniformly mixed nitrile polyurethane mixed latex suitable for preparing medical gloves for standby.

[0034] Step 3) Preparation method of super-soft nitrile medical surgical glove mixed latex 90.5 Kg of nitrile polyurethane mixed latex 9 Kg of styrene-butadiene latex 0.5 Kg of short-chain organically modified polysiloxane Weigh 90.5 Kg of nitrile polyurethane mixed emulsion, then weigh 9 Kg of styrene-butadiene latex and stir at room temperature for 35 min. Then add 0.5 Kg of short-chain organically modified polysiloxane (dilute and stir evenly with 10 times of softened water), and stir at room temperature for 5 hours to obtain a uniformly dispersed mixed latex suitable for preparing super-soft nitrile medical gloves. Among them, the short-chain organically modified polysiloxane is from Evonik Polymer GmbH, model AFCONA-3585; Step 4) Preparation method of super-soft nitrile medical surgical gloves, and its preparation steps include: S1: Clean the mold and dry the cleaned mold; S2: Immerse the dried mold in the coagulant at a temperature of 45 °C for 5 seconds; dry the mold with the attached coagulant at a low temperature (83 °C ± 2); S3: Immerse it in the mixed latex of super-soft nitrile medical surgical gloves at a latex temperature of room temperature 25 - 28 °C for 10 seconds. Take out the mold with the attached latex, and place the mold with the attached latex in a forced-air drying oven and dry it with forced air at a temperature of 110 °C for 3 minutes; S4: Immerse the incompletely dried hand mold in hot water at a temperature of 80 °C for 18 seconds; take out the mold that has entered the hot water and dry it, then immerse the mold in the release agent for 10 seconds, then take it out and dry and vulcanize it. The vulcanization drying temperature is 115 °C and the time is 15 min, and then demold to obtain super-soft nitrile medical surgical gloves; Among them, the coagulant in step S2 includes: Wetting agent 35 Kg Calcium nitrate 300 Kg Wetting agent 6 Kg Calcium stearate 20 Kg Soft water 639 Kg Weigh 639 kg of soft water, heat it by water bath at a temperature of 45 ± 2 °C, and add 300 Kg of solid calcium nitrate, 20 Kg of calcium stearate, and 6 Kg of wetting agent (model: TERIC® 324) in sequence under stirring, and continue to stir until all solid substances are completely dissolved, then filter and reserve; The release agent in step S4 is a polyurethane coating, and the polyurethane coating is SX-643F produced by Shixiu New Materials Technology (Zhejiang) Co., Ltd.

[0035] Example 3 In this example, a preparation method of a super-soft nitrile medical surgical glove and a preparation method are provided, and its preparation steps are specifically as follows: Step 1) Preparation method of sulfurized carboxyl nitrile latex 92.4 Kg of Kumho nitrile 838 latex 1.6 Kg of KOH (5%) 2.4 Kg of antioxidant (KY-616) 0.6 Kg of sulfur (S) 1.6 Kg of ZnO 1.4 Kg of ZDC Take 92.4 g of carboxylated nitrile latex, add 1.6 Kg of KOH (5%) to adjust the pH to 9 - 10, and then sequentially add 2.4 Kg of antioxidant (KY-616), 0.6 Kg of S, 1.6 Kg of ZnO, and 1.4 Kg of ZDC, and then vulcanize at room temperature for 16 hours to obtain vulcanized carboxylated nitrile latex for standby.

[0036] Step 2) Preparation method of nitrile polyurethane mixed emulsion 95 Kg of vulcanized carboxylated nitrile latex 5 Kg of aqueous polyurethane emulsion Weigh 95 Kg of vulcanized carboxylated nitrile latex, and then add 5 Kg of aqueous polyurethane emulsion (Covestro, model: DLN-SD), and stir at a temperature of 38 ± 2 °C for 3 h. Some double bond functional groups in the nitrile latex react chemically with the isocyanate groups (-NCO) or amine groups in the aqueous polyurethane to form a cross-linked structure and obtain a uniformly mixed latex solution suitable for the preparation of medical gloves for standby.

[0037] Step 3) Preparation method of super-soft nitrile medical surgical glove mixed latex 96.7 Kg of nitrile polyurethane mixed emulsion 3.0 Kg of styrene-butadiene latex 0.3 Kg of short-chain organically modified polysiloxane Weigh 96.7 Kg of nitrile polyurethane mixed emulsion, then weigh 3.0 Kg of styrene-butadiene latex and stir at room temperature for 35 min, and then add 0.3 Kg of short-chain organically modified polysiloxane (diluted and stirred evenly with 10 times of softened water), and stir at room temperature for 5 h to obtain a uniformly dispersed mixed latex suitable for the preparation of super-soft nitrile medical gloves. Among them, the short-chain organically modified polysiloxane is from Evonik Degussa GmbH, model AFCONA-3585; Step 4) Preparation method of super-soft nitrile medical surgical gloves, and its preparation steps include: S1: Clean the mold and dry the cleaned mold; S2: Immerse the dried mold in the coagulant at a temperature of 45 °C for 5 s; dry the mold with the attached coagulant at a low temperature (83 °C ± 2); S3: Immerse it into the super-soft nitrile medical surgical glove mixed latex. The temperature of the latex is normal temperature, 25 - 28°C. The mold stays in the latex for 10 seconds. Take out the mold with attached latex and place it in a forced-air drying oven, and dry it with forced air at a temperature of 110°C for 3 minutes; S4: Immerse the not fully dried hand mold into hot water at a temperature of 80°C. The mold stays in the hot water for 18 seconds. Take out the mold that has entered the hot water and dry it. Then immerse the mold into the release agent. The mold stays in the release agent for 10 seconds. Then take it out and dry and vulcanize it. The vulcanization drying temperature is 115°C and the time is 15 min. Then demold it to obtain the super-soft nitrile medical surgical glove; Among them, the coagulant in step S2 includes: Wetting agent 35 Kg Calcium nitrate 300 Kg Wetting agent 6 Kg Calcium stearate 20 Kg Soft water 639 Kg Weigh 639 kg of soft water. By means of water bath heating at a temperature of 45 ± 2°C, while stirring, add 300 Kg of solid calcium nitrate, 20 Kg of calcium stearate, and 6 Kg of wetting agent (model: TERIC® 324) in sequence, and continuously stir until all solid substances are completely dissolved, and filter for standby; The release agent in step S4 is a polyurethane coating, and the polyurethane coating uses SX-643F produced by Shixiu New Material Technology (Zhejiang) Co., Ltd.

[0038] (II) Performance test 1) Test method Performance test: The nitrile medical surgical glove refers to ASTM D3577 (synthetic rubber), type I dumbbell cut piece (width 6 mm); 2) Test results The performance test results are shown in Table 1 below: Table 1: Performance test results of gloves prepared in the examples and comparative examples

[0039] It can be seen from Comparative Example 1-1 that by using vulcanized carboxylated nitrile latex to prepare nitrile latex gloves, its various performances relatively do not meet the technical requirements of synthetic latex medical gloves.

[0040] It can be seen from Comparative Example 1-3 that without adding short-chain organically modified polysiloxane in the system, the surface leveling effect of the glove is not good, the glove is prone to being thin, and the softness is not ideal. Therefore, the tensile performance and elongation at break performance of the glove do not meet the mechanical property requirements of medical gloves.

[0041] From Comparative Examples 1-4, we can see that without adding styrene-butadiene latex into the system, the gloves have more marks on the surface and the appearance is uneven. From the results of the mechanical properties test, we can also see that although the tearing force of the gloves meets the requirements, the directional load does not meet the requirements of medical gloves.

[0042] According to Comparative Examples 1-6, no aqueous polyurethane solution is added to the system, and the tear force, elongation at break, and 500% directional load of the gloves do not meet the technical requirements of nitrile medical surgical gloves.

[0043] Comparative Examples 1-2 show that when the unvulcanized Kumho Nitrile 838 latex is used to replace the vulcanized carboxyl nitrile latex, the film formation of the gloves is not ideal and its performance cannot be tested; Comparative Examples 1-5 show that when the nitrile latex is not added, the gloves are pure water-based polyurethane gloves (Covestro Polyurethane: DLN-SD), the gloves cannot be formed and their performance cannot be tested.

[0044] The present invention adopts the unique carbamate group (-NH-CO-O-) in the waterborne polyurethane molecular chain, and its molecular structure has unique flexibility. The flexible chain segment can play a role similar to a "lubricant" in the polymer system of nitrile latex, and can also play a role of spacing and connection between molecular chains, thereby increasing the distance between molecular chains and reducing the interaction force between molecular chains, such as van der Waals force, so that the molecular chains of the entire system are easier to slide relative to each other, thereby making the gloves and other products made of nitrile latex softer.

[0045] In addition, the present invention makes full use of the amino, carbonyl and other functional groups in the polyurethane molecules to form hydrogen bonds with the cyano (-CN), amide (-CONH -) and other functional groups in the nitrile latex, and can also form physical entanglements with the nitrile chain segments. This hydrogen bonding and physical entanglement limit the excessive movement of the molecular chain to a certain extent, but will not make the system rigid, but instead form a structure similar to an "elastic network". This structure can undergo reversible deformation when subjected to external force, and can return to its original state when the external force disappears, thereby giving the nitrile latex better flexibility and making the product feel softer.

[0046] The invention utilizes the difference between the copolymer structure of styrene and butadiene contained in styrene-butadiene rubber and the copolymer structure of diene and acrylonitrile in nitrile-butadiene latex, so that they can fill the gaps with each other when mixed to form a more uniform network structure, thereby improving the leveling performance of the latex.

[0047] The present invention utilizes the harmonization of polarity differences. Specifically, nitrile latex has a relatively high polarity, while styrene-butadiene latex has a relatively low polarity. This polarity difference enables styrene-butadiene latex to act as a harmonizing agent, reducing the surface tension of nitrile latex and making it easier to spread on the substrate, thereby improving the leveling effect and greatly enhancing the appearance of medical surgical gloves.

[0048] The styrene portion of styrene-butadiene rubber can form certain hydrogen bonds or van der Waals forces with the acrylonitrile portion of nitrile latex. This interaction helps to improve the cohesion of the latex, enabling it to maintain a uniform distribution during the drying process, reducing shrinkage and deformation, and enhancing its flexibility and plasticity.

[0049] The present invention utilizes the flexibility and network structure of short-chain organically modified polysiloxane to form a flexible network structure in nitrile latex. This flexible network structure can absorb external stress, reduce crack propagation, thereby improving the toughness and impact resistance of the gloves. In addition, the flexible chain segments of polysiloxane can also reduce the overall modulus of the rubber, making the material softer.

[0050] The present invention utilizes the fact that short-chain organically modified polysiloxane has a relatively low surface tension, which can reduce the surface tension of nitrile rubber, making it easier to spread and wet when in contact with other materials. For nitrile products with extremely high surface quality requirements, such as those that need to be very smooth and have no obvious defects (such as orange peel phenomenon, pinholes, etc.). The present invention utilizes short-chain organically modified polysiloxane to improve the smoothness of the glove surface: imparting a smooth feel similar to silicone oil to the surface of nitrile medical surgical gloves, reducing the surface friction coefficient, facilitating demolding and subsequent processing, and at the same time enhancing the touch and user experience of the product. Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A latex, characterized in that, It includes a nitrile polyurethane mixed emulsion, a styrene-butadiene latex, and a short-chain organically modified polysiloxane, wherein the nitrile polyurethane mixed emulsion is prepared by mixing a carboxylated nitrile latex and an aqueous polyurethane emulsion.

2. A latex according to claim 1, characterized in that, By weight, the latex includes 88-96 parts of the nitrile polyurethane mixed emulsion, 1-10 parts of the styrene-butadiene latex, and 0.1-0.5 part of the short-chain organically modified polysiloxane; It is prepared by mixing the nitrile polyurethane mixed emulsion, the styrene-butadiene latex, and the short-chain organically modified polysiloxane and stirring at 20-40 °C for 4-6 hours.

3. A latex according to claim 1, characterized in that, By weight, the nitrile polyurethane mixed emulsion is prepared by mixing 85-97 parts of the carboxylated nitrile latex and 3-15 parts of the aqueous polyurethane emulsion and stirring at 35-45 °C for 2-4 h.

4. A latex according to claim 3, wherein, The preparation method of the carboxylated nitrile latex is as follows: By weight, take the carboxylated nitrile latex, add a stabilizer, and then sequentially add an antioxidant, sulfur, an activator, and a promoter, and then vulcanize at room temperature for 14-18 hours to obtain the carboxylated nitrile latex.

5. A latex according to claim 3, characterized in that, The preparation method of the carboxylated nitrile latex is as follows: By weight, take 88-96 parts of the carboxylated nitrile latex, add KOH to adjust the pH to 9-10, and then sequentially add 1.0-3.0 parts of an antioxidant, 0.6-1.6 parts of sulfur, 0.6-2 parts of an activator, and 0.8-1.5 parts of a promoter, and then vulcanize at room temperature for 14-18 hours to obtain the carboxylated nitrile latex.

6. A latex according to claim 4, characterized in that, The carboxylated nitrile latex is one or both of LG Chemical nitrile latex NL125 and Kumho nitrile 823 latex; The stabilizer is one or both of ammonia water (NH3•H2O) and KOH; The promoter is at least one or more of tetramethylthiuram disulfide (TMTD), zinc dibutyldithiocarbamate (ZDBC), and zinc diethyldithiocarbamate (ZDC); The antioxidant is at least one or more of antioxidant 616 (butylated product of cresol and dicyclopentadiene), antioxidant BHT (2,6-di-tert-butyl-4-methylphenol), and antioxidant 264 (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]); The activator is one or both of ZnO and zinc carbonate (ZnCO3).

7. A super-soft nitrile medical surgical glove, characterized in that, It is prepared by using the latex described in any one of claims 1-6.

8. A preparation method of a super-soft nitrile medical surgical glove as described in claim 7, characterized in that, Its preparation steps include: S1: Clean the mold and dry the cleaned mold. S2: Immerse the dried mold in a coagulant, and the mold stays in the coagulant for 1-10 seconds; dry the mold with the attached coagulant at a low temperature. S3: Immerse it in the super-soft nitrile medical surgical glove mixed latex, and the mold stays in the latex for 8-11 seconds. Take out the mold with the attached latex, and place the mold with the attached latex in a forced-air drying oven and dry it by forced air at 90-130 °C for 1-6 minutes. S4: Immerse the incompletely dried hand mold in hot water and let the mold stay in the hot water for 10 - 30 seconds; take out the mold that has entered the hot water and dry it, then immerse the mold in the release agent, and then take it out for drying and vulcanization, and then demold to obtain the ultra-soft nitrile medical surgical gloves.

9. The preparation method of a super-soft nitrile medical surgical glove according to claim 8, characterized in that, The coagulant in step S2 includes: Wetting agent 30 - 40 Kg Calcium nitrate 250 - 350 Kg Humectant 3 - 8 Kg Calcium stearate 10 - 30 Kg Soft water 600 - 700 Kg; Weigh the soft water, and in the state of stirring, add calcium nitrate, calcium stearate, and wetting agent in sequence by means of water bath heating, and continue to stir until all solid substances are completely dissolved, and then filter for standby.

10. The preparation method of a super-soft nitrile medical surgical glove according to claim 8, characterized in that, The release agent is a polyurethane coating liquid, and the polyurethane coating liquid adopts SX-643F produced by Shixiu New Material Technology (Zhejiang) Co., Ltd.

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