A natural rubber condom and its production process

Abstract

The application belongs to the technical field of contraceptive manufacturing, and particularly relates to a natural latex condom and a production process thereof, wherein the natural latex condom comprises the following raw materials in parts by weight: modified latex 100 parts, cleaning agent 10 parts, vulcanizing agent 1.5-2.1 parts, casein 0.5 parts, diffusing agent NF 0.15-0.5 parts, ammonia water 0.15 parts and anti-aging agent DOD 0.75-1.5 parts, and the modified latex is prepared by grafting functional proteins, which not only improves the pore density of the formed latex, but also gives the product higher elasticity and toughness. In the production process, the cleaning step of the added cleaning agent significantly reduces the residue of white carbon black lumps, effectively improves the production efficiency and product quality, and improves the use comfort.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of contraceptive product manufacturing, and particularly relates to a natural rubber condom and a production process thereof. BACKGROUND

[0002] Natural rubber is widely used in the preparation of condom products due to its excellent elasticity and biocompatibility, but traditional latex condoms generally face two major problems: first, residual impurities in the latex can easily cause allergic reactions in users, and although multiple leaching treatments have been performed, the allergen removal rate still cannot meet the needs of high-sensitivity groups; second, inorganic fillers such as white carbon black added to enhance the mechanical properties are easily doped in the form of powder blocks on the surface, which not only affects the comfort of touch, but also may release microparticles in the body fluid environment, causing biological safety hazards. Existing modification techniques mostly use silicone oil coating to reduce the friction coefficient, or halogenation treatment to improve the material density, but these methods are difficult to simultaneously achieve the synergistic improvement of biological functionalization and physical properties.

[0003] In recent years, protein grafting modification has become a research hotspot, aiming to endow condoms with biological activities such as antibiosis and repair promotion. However, physically mixed proteins are severely denatured and inactivated at high vulcanization temperatures, surface coatings are easily detached and ineffective due to weak adhesion, and although irradiation grafting can achieve covalent bonding, high-energy radiation can damage the polyisoprene molecular chains in the latex molecules, resulting in a sharp decrease in breaking elongation. In addition, traditional cleaning processes rely on strong acids, strong bases or organic solvents, which can easily corrode the latex network while removing powder blocks, accelerating material aging.

[0004] In view of the above problems, it is urgent to develop a condom based on natural rubber, which can improve the use comfort while achieving high elasticity, high density and biological safety of the condom. SUMMARY

[0005] In view of the above situation, the present application provides a natural rubber condom and a production process thereof, which forms a covalent bond between natural rubber and functional proteins through free radical grafting technology, improves the elasticity, density and safety of the latex condom, and adds calcium silicate whiskers and increases the cleaning agent cleaning process to solve the problem of white carbon black powder block residue, and improve the product quality and use comfort.

[0006] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0007] The present application provides a natural rubber condom, which comprises the following raw materials by weight: modified latex 100 parts, cleaning agent 10 parts, vulcanizing agent 1.5-2.1 parts, casein 0.5 parts, diffuser NF 0.15-0.5 parts, ammonia 0.15 parts and anti-aging agent DOD 0.75-1.5 parts.

[0008] Further, the cleaning agent is composed of HPMC (hydroxypropyl methyl cellulose), alkyl polyglycoside, PVP (polyvinyl pyrrolidone), liquid paraffin and deionized water with a mass ratio of 0.4:0.8:0.3:1.5:97.

[0009] Further, the vulcanizing agent is composed of promoter EZ and sulfur with a mass ratio of 1:2.

[0010] Further, the modified latex comprises the following raw materials: natural latex, functional protein, APS (ammonium persulfate), white carbon black, calcium silicate whisker, zinc oxide, ascorbic acid, polysorbate 80 and soft water.

[0011] The specific preparation method of the modified latex is as follows:

[0012] S1: white carbon black, calcium silicate whisker and zinc oxide are weighed and mixed and ball milled for 30 min to obtain an activating agent, natural latex is taken and the activating agent is added thereto, and heated and stirred to disperse, so that the molecular surface active groups of the natural latex are exposed to form a preliminary crosslinking structure, and the activated latex is obtained;

[0013] S2: the functional protein and polysorbate 80 are weighed and dispersed in soft water, and stirred and dissolved at 40 DEG C, so that the functional groups of the protein molecules are fully exposed, and the protein grafting solution is obtained by filtering through a 0.22 mu m filter membrane to remove bacteria;

[0014] S3: the protein grafting solution is added to the activated latex, nitrogen is blown to eliminate dissolved oxygen and ensure the reaction efficiency, and then APS is added, and heated and stirred to react for 2 h, so that the sulfate radical is generated by thermal decomposition of the APS, the polyisoprene chain in the natural latex and the molecular residues of the functional protein are initiated to form free radicals, covalent grafting occurs, and the protein grafting latex is obtained;

[0015] S4: after the protein grafting latex is rapidly cooled to room temperature, ascorbic acid is weighed and added thereto to neutralize the APS, and the modified latex is obtained.

[0016] Further, the mass ratio of the natural latex, the functional protein, the APS, the white carbon black, the calcium silicate whisker, the zinc oxide, the ascorbic acid, the polysorbate 80 and the soft water is 100:5-10:0.1-0.3:10:2:0.75:0.5:0.5:77-82.

[0017] Further, the functional protein is selected from any one of gelatin, silk fibroin, mussel adhesive protein and elastin.

[0018] The application further provides a production process of the natural latex condom.

[0019] Step 1: weigh casein 0.5 parts, diffusion agent NF 0.15-0.5 parts and ammonia 0.15 parts are dissolved in deionized water to obtain a stabilizer, weigh modified latex 100 parts and place in a vacuum stirrer, then sequentially add the stabilizer, vulcanizing agent 1.5-2.1 parts and antioxidant DOD 0.75-1.5 parts, continuously stir for 1 h, and vacuum degassing to obtain an impregnation solution;

[0020] Step 2: the forming mold for forming the condom is cleaned, dried, cooled and fumigated to maintain a relative humidity RH>90%, to obtain a to-be-impregnated mold, the to-be-impregnated mold is immersed in the impregnation solution at a temperature of 30-36 DEG C for 5-15 s, slowly taken out, cooled and formed, then immersed in the impregnation solution again for 10 s, taken out and formed into a film, to obtain a film forming condom;

[0021] Step 3: take cleaning agent 10 parts, soak the film forming condom in the cleaning agent to remove the surface powder, then transfer to a vulcanizing machine for vulcanization, improve the smoothness, and use a rubber roller to roll the film forming condom on the forming mold after vulcanization, and then water is used to remove the mold, to obtain a semi-finished product;

[0022] Step 4: sterilize, dry, inspect and package the semi-finished product to obtain a natural latex condom.

[0023] Further, a lubricating liquid is added in the packaging process, and the lubricating liquid is composed of purified water, glycerol, propylene glycol, hydroxyethyl cellulose, hydantoin, carbomer 940, sodium hyaluronate and tea tree essential oil in a mass ratio of 75.5:12:8:0.8:0.2:0.3:0.15:0.05.

[0024] The beneficial effects obtained by the present application are as follows:

[0025] The natural latex condom prepared by the present application grafts the functional protein into the molecular chain of the natural latex through a free radical covalent bond, not only completely seals the exposed sites of the allergenic protein in the latex, but also further improves the pore density of the natural latex after forming, significantly reduces the risk of allergy, and at the same time, imparts higher elasticity and toughness to the condom. In addition, the modified latex also has the biological activity of the functional protein, such as the antibacterial activity of the mussel mucin, the biocompatibility of the elastin and the adhesion of the silk fibroin. Unlike the traditional process which relies on inorganic fillers to enhance the performance, the calcium silicate whisker and the white carbon black are dispersed in polysorbate 80, which further fills the latex pores from the micro level, eliminates the hidden danger of powder doped, and cooperates with the protein network to build a composite structure with both rigidity and flexibility, so that the product has high elasticity and tear resistance.

[0026] In the constructed cleaning agent system, the HPMC forms a hydrophilic film on the surface of the film forming sleeve, physically wrapping the residual particles; the alkyl glycoside reduces the interfacial tension, making the powder block more easily peeled off; the liquid paraffin penetrates into the microscopic recesses to improve smoothness, and the three play a synergistic effect, avoiding the damage of traditional organic solvents to the protein grafted layer. In the process, the protein grafting reaction is carried out in the gel state formed by pre-vulcanization, which not only ensures the full exposure of the protein active site, but also realizes cross-linking reinforcement by adding the vulcanizing agent before the final vulcanization, so that the biological function and mechanical property are improved synchronously.

[0027] In summary, the present application takes protein grafting as the core, realizes the high elasticity, low immunogenicity and removal of residual powder block of natural latex condoms and other long-term industry pain points through material innovation and process improvement. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The production process flow chart of the natural latex condom of the present application is shown in the figure;

[0029] Figure 2 The protein grafting rate detection results of the modified latex prepared in Examples 1-4 are shown in the table;

[0030] Figure 3 The surface residual powder block investigation results of the natural latex condoms prepared in Example 2 and Comparative Example 2 are shown in the table;

[0031] Figure 4 The moisture permeability investigation results of the natural latex condoms prepared in Examples 1-4 and Comparative Examples 1-2 are shown in the table. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0033] Unless otherwise defined, all professional and scientific terms used in the present application have the same meanings as familiar to those skilled in the art. In addition, any method and material similar or equivalent to those described in the present application can be applied in the present application. The preferred implementation methods and materials described in the present application are only for demonstration, but cannot limit the content of the present application.

[0034] In the following examples, unless otherwise specified, all are conventional methods; Figure 1This is a flow chart of the production process of the natural latex condom of the present invention; the materials used in the following examples are all medical grade or food grade, and unless otherwise specified, the raw materials are all new materials purchased from the market, and the parts mentioned are all by weight. Among them, the solid content of the natural latex used is 44%; the gelatin used is type A gelatin; the silk fibroin used is a soluble freeze-dried powder with a purity ≥98% and a molecular weight of 100-150 kDa; the mussel adhesive protein used has a DOPA content of 10% and a molecular weight of 100 kDa; the elastin used is human elastin I; the silica used is obtained by gas phase method, with a particle size of 8-17 nm and a specific surface area >190 m². 2 / g; the calcium carbonate whiskers used are needle-shaped β-type, with a diameter of 0.5-1 μm and a length of 50-100 μm; the zinc oxide used is nano-sized, with a particle size of 30-50 nm and a dry weight fraction of ≥97%; the polysorbate 80 used has an HLB of 15 and an acid value of ≤2 mg KOH / g; the HPMC used is model 2208; the PVP used is PVP K30 with an average molecular weight of 58 kDa; and the ammonia water used has a mass fraction of 28%.

[0035] In the following examples and comparative examples, the cleaning agent is composed of 0.8 parts HPMC, 1.6 parts alkyl glycoside, 0.6 parts PVPK30, 3 parts liquid paraffin and 194 parts deionized water; the lubricant is composed of 75.5 parts purified water, 12 parts glycerin, 8 parts propylene glycol, 0.8 parts hydroxyethyl cellulose, 0.2 parts hydantoin, 0.3 parts carbomer 940, 0.15 parts sodium hyaluronate and 0.05 parts tea tree oil.

[0036] Example 1: This example provides a natural latex condom, which comprises the following raw materials in parts by weight: 100 parts modified latex, 10 parts cleaning agent, 0.5 parts accelerator EZ, 1 part sulfur, 0.5 parts casein, 0.15 parts dispersant NF, 0.15 parts ammonia water, and 0.75 parts antioxidant DOD.

[0037] The modified latex comprises the following raw materials in parts by weight: 100 parts natural latex, 5 parts gelatin, 0.1 parts APS, 10 parts silica, 2 parts calcium silicate whiskers, 0.75 parts zinc oxide, 0.5 parts ascorbic acid, 0.5 parts polysorbate 80, and 82 parts soft water. The specific preparation method of the modified latex is as follows:

[0038] S1: Weigh 10 parts of silica, 2 parts of calcium silicate whiskers and 0.75 parts of zinc oxide and mix them. Use 1 mm zirconium oxide beads to ball mill at 300 rpm for 30 min to obtain an activator. Take 100 parts of natural latex and add the activator to it. Heat and stir at 60℃ for 40 min to expose the surface active groups of the natural latex and form a preliminary cross-linked structure to obtain activated latex.

[0039] S2: Take gelatin 5 parts and polysorbate 80 0.5 parts and disperse in 82 parts of soft water, dissolve at 40℃, 400 rpm magnetic stirring, fully expose the protein molecule functional group, filter sterilization through 0.22 μm PVDF filter membrane, obtain protein grafting solution;

[0040] S3: Add the protein grafting solution to the activated latex, blow in nitrogen to eliminate dissolved oxygen, ensure reaction efficiency, add APS 0.1 parts after detecting that the dissolved oxygen content is lower than 1 ppm, heat and stir at 70℃ for 2 h, make APS thermal decomposition to generate sulfate radical, initiate the formation of free radicals between polyisoprene chain in natural latex and functional protein molecule residues, covalent grafting occurs, and protein grafted latex is obtained;

[0041] S4: After rapidly cooling the protein grafted latex to room temperature, take ascorbic acid 0.5 parts and add it to neutralize APS, and obtain modified latex.

[0042] The embodiment also provides a production process of natural latex condom, which specifically comprises the following steps:

[0043] Step 1: Take casein 0.5 parts, diffusing agent NF 0.15 parts and ammonia water 0.15 parts and dissolve in 5 parts of deionized water, stir at 40℃ until transparent, obtain stabilizer, take modified latex 100 parts and place in a vacuum stirrer, take stabilizer, accelerator EZ 0.5 parts, sulfur 1 part and anti-aging agent DOD 0.75 parts and add them into the vacuum stirrer in sequence, continuously stir for 1 h and vacuum degassing, obtain impregnation solution;

[0044] Step 2: Wash, dry, cool and fumigate the forming mold for condom forming to humidity RH 92%, obtain the mold to be impregnated, immerse the mold to be impregnated in the impregnation solution with a temperature of 33℃ for 15 s, slowly take out and cool to form, immerse again in the impregnation solution for 10 s, take out and form a film, obtain a film forming condom;

[0045] Step 3: Take cleaning agent 10 parts, immerse the film forming condom in the cleaning agent to remove surface powder, then transfer to a vulcanizing machine, steam pressurize at 0.15 MPa for 15 min to improve smoothness, roll edge the film forming condom after vulcanization on the forming mold by using a rubber roller, and water flush demolding by using pure water at 35℃, obtain a semi-finished product;

[0046] Step 4: Sterilize, dry, quality inspect the semi-finished product, add lubricating liquid, seal and package in an aluminum foil bag, obtain a natural latex condom.

[0047] Example 2: The present example provides a natural rubber condom, which comprises the following raw materials by weight: modified rubber 100 parts, cleaning agent 10 parts, accelerator EZ 0.6 parts, sulfur 1.2 parts, casein 0.5 parts, diffuser NF 0.3 parts, ammonia 0.15 parts, and antioxidant DOD 1 part.

[0048] The modified rubber comprises the following raw materials by weight: natural rubber 100 parts, silk fibroin 8 parts, APS 0.2 parts, white carbon black 10 parts, calcium silicate whisker 2 parts, zinc oxide 0.75 parts, ascorbic acid 0.5 parts, polysorbate 80 0.5 parts, and soft water 79 parts, and the specific preparation method is as follows:

[0049] S1: Take 10 parts of white carbon black, 2 parts of calcium silicate whisker, and 0.75 parts of zinc oxide, mix them, and use 1 mm zirconium oxide beads to ball mill at 300 rpm for 30 min to obtain an activator. Take 100 parts of natural rubber and add the activator to it. Stir and disperse at 60°C for 40 min to expose the molecular surface active groups of the natural rubber and form a preliminary crosslinking structure to obtain activated rubber;

[0050] S2: Take 8 parts of silk fibroin and 0.5 parts of polysorbate 80 and disperse them in 79 parts of soft water. Dissolve at 40°C with magnetic stirring at 400 rpm to fully expose the protein molecular functional groups. Filter sterilize through a 0.22 μm PVDF filter membrane to obtain a protein grafting solution;

[0051] S3: Add the protein grafting solution to the activated rubber, and blow in nitrogen to eliminate dissolved oxygen and ensure reaction efficiency. After detecting that the dissolved oxygen content is lower than 1 ppm, add 0.2 parts of APS. Stir and react at 70°C for 2 h to make APS thermally decompose to generate sulfate radicals, initiate the formation of radicals from the polyisoprene chains in the natural rubber and the molecular residues of the functional proteins, and covalently graft to obtain a protein grafted rubber;

[0052] S4: After rapidly cooling the protein grafted rubber to room temperature, add 0.5 parts of ascorbic acid to neutralize the APS to obtain modified rubber.

[0053] The present example also provides a production process for a natural rubber condom, which specifically comprises the following steps:

[0054] Step 1: Dissolve 0.5 parts of casein, 0.3 parts of diffuser NF, and 0.15 parts of ammonia in 5 parts of deionized water at 40°C to obtain a stabilizer. Take 100 parts of modified rubber and place it in a vacuum stirrer. Add the stabilizer, 0.6 parts of accelerator EZ, 1.2 parts of sulfur, and 1 part of antioxidant DOD in sequence, and continuously stir for 1 h to vacuum degassing to obtain an impregnating solution;

[0055] Step 2: a forming mold for condom forming is cleaned, dried, cooled and fumigated to a humidity RH 91%, to obtain a to-be-impregnated mold, the to-be-impregnated mold is immersed in the impregnation liquid at a temperature of 30°C for 10 s, slowly taken out, cooled and formed, then immersed in the impregnation liquid again for 10 s, taken out and formed, to obtain a formed condom;

[0056] Step 3: 10 parts of a cleaning agent are taken, the formed condom is soaked in the cleaning agent to remove surface powder, then transferred to a vulcanizing machine for steam pressurization at 0.15 MPa for 15 min, to improve smoothness, the formed condom on the forming mold after vulcanization is crimped by a rubber roller, and water is used to flush and demold at 35°C, to obtain a semi-finished product;

[0057] Step 4: the semi-finished product is sterilized, dried, quality inspected, sealed and packaged in an aluminum foil bag after adding a lubricating liquid, to obtain a natural latex condom.

[0058] Example 3: a natural latex condom is provided, which comprises the following raw materials in parts by weight: modified latex 100 parts, cleaning agent 10 parts, accelerator EZ 0.7 part, sulfur 1.4 part, casein 0.5 part, diffuser NF 0.5 part, ammonia 0.15 part and anti-aging agent DOD 1.5 part.

[0059] The modified latex comprises the following raw materials in parts by weight: natural latex 100 parts, mussel mucin 10 parts, APS 0.3 part, white carbon black 10 parts, calcium silicate whisker 2 parts, zinc oxide 0.75 part, ascorbic acid 0.5 part, polysorbate 80 0.5 part and soft water 77 parts, and the modified latex is specifically prepared as follows:

[0060] S1: 10 parts of white carbon black, 2 parts of calcium silicate whisker and 0.75 part of zinc oxide are weighed and mixed, ball-milled at 300 rpm with 1 mm zirconium oxide beads for 30 min to obtain an activating agent, 100 parts of natural latex are taken and the activating agent is added thereto, heated and stirred at 60°C for 40 min to expose the molecular surface active groups of the natural latex and form a preliminary crosslinked structure, to obtain activated latex;

[0061] S2: 10 parts of mussel mucin and 0.5 part of polysorbate 80 are dispersed in 77 parts of soft water, 0.04 part of urea is added to reduce the hydrophobic effect of the mussel mucin and promote dissolution, and the solution is dissolved by magnetic stirring at 400 rpm at 40°C, to fully expose the protein molecular functional groups, filtered through a 0.22 μm PVDF filter membrane to remove bacteria, to obtain a protein grafting solution;

[0062] S3: The protein grafting solution is added to the activated latex, nitrogen is blown in to eliminate dissolved oxygen, ensuring the reaction efficiency, after detecting that the dissolved oxygen content is less than 1 ppm, 0.3 parts of APS is added, heated and stirred at 70°C for 2 h, so that the APS is thermally decomposed to generate sulfate radicals, initiating the formation of radicals from the polyisoprene chains in the natural latex and the molecular residues of the functional proteins, covalent grafting occurs, and the protein grafted latex is obtained;

[0063] S4: After the protein grafted latex is quickly cooled to room temperature, 0.5 parts of ascorbic acid is added to neutralize the APS, and the modified latex is obtained.

[0064] The embodiment also provides a production process of a natural latex condom, specifically including the following steps:

[0065] Step 1: 0.5 parts of casein, 0.5 parts of diffuser NF and 0.15 parts of ammonia water are dissolved in 5 parts of deionized water to obtain a stabilizer, 100 parts of modified latex is placed in a vacuum stirrer, and the stabilizer, 0.7 parts of accelerator EZ, 1.4 parts of sulfur and 1.5 parts of anti-aging agent DOD are sequentially added, and the stirring is continued for 1 h to remove bubbles under vacuum to obtain an impregnation solution;

[0066] Step 2: A forming mold for forming a condom is cleaned, dried, cooled and fumigated to a humidity RH of 92% to obtain a to-be-impregnated mold, the to-be-impregnated mold is immersed in the impregnation solution at a temperature of 36°C for 5 s, slowly taken out and cooled to form a film, and then immersed in the impregnation solution again for 10 s, taken out and formed into a film to obtain a film forming sleeve;

[0067] Step 3: 10 parts of a cleaning agent is taken, the film forming sleeve is soaked in the cleaning agent to remove surface powder, and then transferred to a vulcanizing machine for steam pressurization at 0.15 MPa for 15 min to improve smoothness, and the film forming sleeve after vulcanization on the forming mold is crimped by a rubber roller and then water is used to remove the mold to obtain a semi-finished product;

[0068] Step 4: The semi-finished product is sterilized, dried, quality inspected, sealed and packaged in an aluminum foil bag after adding a lubricating liquid to obtain a natural latex condom.

[0069] Embodiment 4: The embodiment provides a natural latex condom, which includes the following raw materials by weight: 100 parts of modified latex, 10 parts of cleaning agent, 0.5 parts of accelerator EZ, 1 part of sulfur, 0.5 parts of casein, 0.4 parts of diffuser NF, 0.15 parts of ammonia water and 1 part of anti-aging agent DOD.

[0070] The modified latex comprises the following raw materials by weight: natural latex 100 parts, elastin 10 parts, APS 0.2 parts, white carbon black 10 parts, calcium silicate whisker 2 parts, zinc oxide 0.75 parts, ascorbic acid 0.5 parts, polysorbate 80 0.5 parts, and soft water 77 parts, and the specific preparation method of the modified latex is as follows:

[0071] S1: 10 parts of white carbon black, 2 parts of calcium silicate whisker, and 0.75 parts of zinc oxide are weighed and mixed, ball-milled with 1 mm zirconium oxide beads at 300 rpm for 30 min to obtain an activator, 100 parts of natural latex is taken and the activator is added thereto, heated and stirred at 60°C for 40 min to disperse, expose the molecular surface active groups of the natural latex, form a preliminary crosslinking structure, and obtain activated latex;

[0072] S2: 10 parts of elastin and 0.5 parts of polysorbate 80 are dispersed in 77 parts of soft water, dissolved by magnetic stirring at 400 rpm at 40°C, the functional groups of the protein molecules are fully exposed, filtered through a 0.22 μm PVDF filter membrane to sterilize, and a protein grafting solution is obtained;

[0073] S3: The protein grafting solution is added to the activated latex, nitrogen is blown to eliminate dissolved oxygen and ensure reaction efficiency, after the dissolved oxygen content is detected to be lower than 1 ppm, 0.2 parts of APS is added, heated and stirred at 70°C for 2 h to make the APS thermally decompose to generate sulfate radicals, initiate the formation of radicals from the polyisoprene chains in the natural latex and the molecular residues of the functional proteins, and covalent grafting occurs to obtain a protein grafted latex;

[0074] S4: After the protein grafted latex is rapidly cooled to room temperature, 0.5 parts of ascorbic acid is weighed and added thereto to neutralize the APS, and a modified latex is obtained.

[0075] The embodiment also provides a production process of a natural latex condom, specifically comprising the following steps:

[0076] Step 1: 0.5 parts of casein, 0.4 parts of diffuser NF, and 0.15 parts of ammonia water are dissolved in 5 parts of deionized water to obtain a stabilizer, 100 parts of the modified latex is placed in a vacuum stirrer, and the stabilizer, 0.5 parts of accelerator EZ, 1 part of sulfur, and 1 part of anti-aging agent DOD are sequentially added thereto, and vacuum degassing is continuously stirred for 1 h to obtain an impregnation solution;

[0077] Step 2: a forming mold for forming a condom is cleaned, dried, cooled, and fumigated to a humidity RH of 92% to obtain a to-be-impregnated mold, the to-be-impregnated mold is immersed in the impregnation solution at a temperature of 35°C for 10 s, slowly taken out and cooled to form, again immersed in the impregnation solution for 10 s, taken out, and formed into a film to obtain a film forming condom;

[0078] Step 3: Take 10 parts of the cleaning agent, immerse the film forming sleeve in the cleaning agent to remove the surface powder, then transfer it to the vulcanizing machine for steam pressurization at 0.15 MPa for 15 min to improve smoothness, use a rubber roller to roll the vulcanized film forming sleeve on the forming mold, and then use pure water at 35°C to water flush and demold to obtain a semi-finished product;

[0079] Step 4: Sterilize, dry, and quality inspect the semi-finished product, then add a lubricating liquid and seal and package it in an aluminum foil bag to obtain a natural latex condom.

[0080] Comparative Example 1 differs from Example 2 in that no silk fibroin is added, and the rest is the same as Example 2.

[0081] Comparative Example 2 differs from Example 2 in that no cleaning agent is used for cleaning, and the rest is the same as Example 2.

[0082] Protein grafting rate investigation

[0083] The gelatin, silk fibroin, mussel mucin, and elastin used in Examples 1-4 were respectively incubated with FITC (fluorescein isothiocyanate) in a pH 9.0 carbonate buffer solution in the dark for 4 h, and then dialyzed to remove free fluorescein to obtain FITC-labeled proteins. The modified latex was prepared according to the protein grafting method in Examples 1-4, and then dialyzed in a 200 kDa dialysis bag to remove free proteins. In a laser confocal microscope, the fluorescence signal was collected at a 488 nm argon ion laser excitation and a 518 nm channel. According to the standard curve of the FITC-labeled protein, the grafting density was calculated, and the grafting rate% = (grafted protein amount / initial protein amount) × 100%. The results are shown in Table 2. Figure 2 .

[0084] Tensile property test

[0085] The natural latex condom samples prepared in Examples 1-4 and Comparative Examples 1-2 were cut into samples with a gauge length of 25 mm and a width of 4 mm, and then conditioned in an environment of 23±2°C and RH 50±5% for 24 h. A universal material testing machine was used to stretch the samples at a constant speed of 500±25 mm / min until they broke, and the force-displacement curve was recorded in real time. The tensile strength was calculated by dividing the maximum load by the initial cross-sectional area (thickness × width), and the elongation at break was calculated as (gauge length at break - initial gauge length) / initial gauge length × 100%. Ten samples were tested for each group, and the average value was taken. The water leakage and air burst properties were also investigated, and the results are shown in Table 1.

[0086] Surface powder density detection

[0087] Take 10×10 mm 2The natural latex condom samples prepared in Example 2 and Comparative Example 2 were dried by critical point drying, then sprayed with 5 nm thick gold-palladium alloy, observed under a scanning electron microscope at an acceleration voltage of 5 kV, and three 1 mm 2 areas were selected for imaging; the number of particles with a particle size > 1 μm in the field of view was counted using ImageJ software, and the bulk density = total number of particles / observation area (pieces / mm 2 ), and the average of three areas was taken, and the results are shown in Figure 3 .

[0088] Moisture permeability test

[0089] The natural latex condom samples prepared in Examples 1-4 and Comparative Examples 1-2 were sealed in a moisture permeable cup, the cup contained saturated potassium chloride solution, RH 95% was maintained, the moisture permeable cup was placed in a 37°C constant temperature oven, the environmental humidity was RH 50%, and after 72 h the mass of the moisture permeable cup was measured, and the moisture permeation rate = mass loss mg / moisture permeable cup opening area cm 2 was calculated, and the results are shown in Figure 4 .

[0090] Table 1 Tensile properties

[0091]

[0092] The results in Table 1 show that the natural latex condom prepared in Example 2, which was modified with silk fibroin, had the highest tensile strength and the best elasticity, which was due to the high elasticity of silk fibroin itself. Compared with the unmodified latex in Comparative Example 1, the other samples all had good mechanical properties, indicating that protein modification has a positive effect on the performance enhancement of natural latex.

[0093] Figure 2 The results show that the modified latex prepared in Examples 1-4 has a protein grafting rate of more than 60%, mainly because the macromolecular protein has a large modification grafting steric hindrance in the latex network, but the performance improvement effect is obvious.

[0094] Figure 3 The results show that the natural latex condom washed with the cleaning agent has fewer residual bulk particles on the surface and a smooth surface. The surface bulk densities of the natural latex protein condoms prepared in Example 2 and Comparative Example 2 were 0.8 pieces / cm 2 and 25.6 pieces / cm 2 respectively, and the cleaning agent had a significant effect, solving the problem of residual silica bulk.

[0095] Figure 4 The results show that the natural latex condom prepared in Comparative Example 2 without protein modification has poor moisture permeability and low pore density, indicating that the grafted protein can efficiently fill the pores of the latex molecules, reduce the risk of leakage or damage, and improve production efficiency.

[0096] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary and that changes in form and detail can be made without departing from the spirit and scope of the application, which is defined by the appended claims and their equivalents.

[0097] The above description of the application and its embodiments is not restrictive, and the embodiments shown in the drawings are only one of the embodiments of the application, and the actual application is not limited thereto. In general, if a person skilled in the art is inspired by it, without departing from the purpose of the invention, without creative design, similar ways and embodiments of the technical solution should belong to the protection scope of the application.

Claims

1. A natural rubber condom, characterized in that, The natural rubber condom comprises the following raw materials by weight: modified rubber 100 parts, cleaning agent 10 parts, vulcanizing agent 1.5-2.1 parts, casein 0.5 parts, diffusing agent NF 0.15-0.5 parts, ammonia 0.15 parts and anti-aging agent DOD 0.75-1.5 parts; The cleaning agent is composed of hydroxypropyl methyl cellulose, alkyl glycoside, polyvinyl pyrrolidone, liquid paraffin and deionized water in a mass ratio of 0.4:0.8:0.3:1.5:97; The modified rubber comprises the following raw materials: natural rubber, functional protein, ammonium persulfate, white carbon black, calcium silicate whisker, zinc oxide, ascorbic acid, polysorbate 80 and soft water; The functional protein is selected from any one of gelatin, silk fibroin, mussel mucin and elastin; The preparation method of the modified rubber is as follows: S1: after ball milling white carbon black, calcium silicate whisker and zinc oxide, the materials are dispersed in natural rubber to obtain activated rubber; S2: functional protein and polysorbate 80 are weighed and dissolved to obtain a protein grafting solution; S3: the protein grafting solution is added to the activated rubber, and then ammonium persulfate is added after nitrogen treatment to obtain a protein grafting rubber; S4: ascorbic acid is weighed and added to the protein grafting rubber to obtain modified rubber.

2. A natural rubber condom according to claim 1, characterized in that, The mass ratio of the natural rubber, functional protein, ammonium persulfate, white carbon black, calcium silicate whisker, zinc oxide, ascorbic acid, polysorbate 80 and soft water is 100:5-10:0.1-0.3:10:2:0.75:0.5:0.5:77-82.

3. A natural rubber condom according to claim 2, characterised in that, The vulcanizing agent is composed of accelerator EZ and sulfur in a mass ratio of 1:

2.

4. A process for the production of a natural rubber condom as claimed in any one of claims 1 to 3, wherein, Specifically comprises the following steps: Step 1: casein, diffusing agent NF and ammonia are weighed and dissolved to obtain a stabilizer, and the stabilizer, vulcanizing agent and anti-aging agent DOD are added to the modified rubber to obtain an impregnating solution; Step 2: the forming mold is cleaned and fumigated, and then immersed in the impregnating solution twice to form a film sleeve; Step 3: the film sleeve is soaked in the cleaning agent, and then vulcanized and demolded to obtain a semi-finished product; Step 4: the semi-finished product is sterilized, dried, inspected and packaged to obtain a natural rubber condom.

5. A process for the production of natural rubber condom as claimed in claim 4, wherein, In step 4, a lubricating liquid is added during the packaging process, and the lubricating liquid is composed of purified water, glycerol, propylene glycol, hydroxyethyl cellulose, hydantoin, carbomer 940, sodium hyaluronate and tea tree essential oil in a mass ratio of 75.5:12:8:0.8:0.2:0.3:0.15:0.05.

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