Hydrophilic rubber as well as preparation method and application thereof

Abstract

The invention discloses hydrophilic rubber and a preparation method and application thereof. The hydrophilic rubber comprises modified rubber, and the surface of the modified rubber is covered with a hydrophilic polymer coating; the modified rubber is prepared by the following steps: treating isoprene rubber or natural rubber by using an epoxidation reagent and a strong oxidant. The modified rubber and the hydrophilic polymer coating form covalent grafting through hydrogen bond complexation or through ester bonds and ether bonds, the hydrophilic polymer coating enables the hydrogen bonds not to be easily damaged by a small molecule solvent, the hydrogen bonds are beneficial to improving the stability of the hydrophilic coating, and the rubber keeps hydrophilic lubricity through cooperation. The hydrophilic rubber disclosed by the invention has good biocompatibility and is non-irritant to skin. The hydrophilic rubber disclosed by the invention can be applied to self-lubricating condoms, and the surface friction coefficient of the condoms can be greatly reduced after the surface coatings of the condoms are in contact with water, aqueous solutions or body fluid.

Description

Technical Field

[0001] The invention belongs to the technical field of modified rubber, and in particular relates to a hydrophilic rubber and a preparation method and application thereof. Background Art

[0002] Commercial condoms are mainly used for female contraception and prevention of sexually transmitted diseases during sexual intercourse. Natural rubber condoms have always occupied the largest market share due to their advantages such as low price, strong elasticity and good skin feel. However, the surface of natural rubber is highly hydrophobic. When it comes into direct contact with human skin or mucous membranes and slides relative to each other, the high friction will cause discomfort or even pain to the user, cause tissue damage, and increase the risk of infection.

[0003] The most common way to increase the lubricity and usability of commercial natural rubber latex condoms is to apply oily or water-based lubricants to the surface of the condom. Oily lubricants have been gradually eliminated from commercial products because they can easily cause changes in the material of natural rubber, are greasy and difficult to clean, and remain in the female body and are difficult to decompose. Although water-based lubricants have overcome the above shortcomings of oily lubricants, the amount of lubricant added to condoms is limited. During sexual intercourse, the lubricant is diluted by body fluids and absorbed by the skin and mucous membranes, resulting in insufficient lubrication to support the entire sexual intercourse process. This causes the condom to become dry in the later stages of sexual intercourse, the friction increases sharply, and the user experience is seriously reduced.

[0004] In this regard, it is necessary to modify the surface of the condom to improve its performance. CN110467741A discloses a technology for grafting zwitterionic polymers on the surface of condoms. The invention solves the lubrication problem during the use of condoms, obtains a hydrophilic coating with strong bonding, stability and good lubrication performance on the surface of the condom, and can greatly improve the comfort of condom use. However, the invention still has some problems: 1. The use of a new type of zwitterionic polymer material has certain safety risks; 2. The use of free radical initiated polymerization grafting technology, such as the use of free radical initiators such as benzophenone and azobisisobutyronitrile, the residues of these compounds on the surface of the condom will bring certain safety risks; 3. The grafting reaction time is 3-6 hours, and the process time is too long and is not conducive to large-scale commercial production. Therefore, it is urgent to develop a natural rubber latex condom that is environmentally friendly, safe, has good hydrophilic properties and can be quickly prepared. Summary of the invention

[0005] In order to overcome the problems existing in the above prior art, one of the purposes of the present invention is to provide a hydrophilic rubber. The second purpose of the present invention is to provide a method for preparing the above hydrophilic rubber. The third purpose of the present invention is to provide an application of the above hydrophilic rubber.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] The first aspect of the present invention provides a hydrophilic rubber, including a modified rubber, wherein the surface of the modified rubber is covered with a hydrophilic polymer coating; the modified rubber is prepared by the following steps: treating isoprene rubber or natural rubber with an epoxidizing agent and a strong oxidizing agent.

[0008] Isoprene rubber or natural rubber is a kind of rubber with polyisoprene as the main component, and also contains a certain proportion of protein, fatty acids, ash, sugars and other non-rubber substances. The chemical formula of polyisoprene is:

[0009]

[0010] Polyisoprene contains olefin double bonds, which are relatively active functional groups. The main reason for rubber aging is that the olefin double bonds are oxidized by oxygen or ozone in the air.

[0011] By utilizing the double bond characteristics of polyisoprene, the present application first oxidizes the olefins in the polyisoprene into epoxide, vicinal diol, and carboxylic acid. The specific reaction formula is as follows:

[0012]

[0013] Then, the highly safe hydrophilic polymer that has been used on the market for a long time is grafted to the surface of isoprene rubber or natural rubber through hydrogen bonds, ether bonds and ester bonds to form a hydrophilic polymer coating. When in contact with water and without adding external lubricants, the lubricity of isoprene rubber or natural rubber condoms can be greatly improved, satisfying the user's comfort and sense of security at the same time.

[0014] Preferably, the material of the hydrophilic polymer coating is selected from one or more of polyvinyl alcohol, sodium polyacrylate, polyethylene oxide, and sodium hyaluronate.

[0015] More preferably, the molecular weight of the polyvinyl alcohol is 170,000-220,000; the molecular weight of the sodium polyacrylate is 3 million-7 million; the molecular weight of the polyethylene oxide is 3 million-7 million; and the molecular weight of the sodium hyaluronate is 1.7 million-2.2 million.

[0016] Preferably, the epoxidation agent is selected from one or more of inorganic peroxides, organic peroxyacids, and inorganic peroxyacids; and the strong oxidant is a permanganate oxidant or a periodate oxidant.

[0017] More preferably, the organic peracid includes one or more of performic acid, peracetic acid, perbenzoic acid, meta-chloroperbenzoic acid, and peroxytrifluoroacetic acid; the inorganic peracid includes persulfuric acid; the inorganic peroxide includes one or more of hydrogen peroxide and potassium persulfate; the periodic acid oxidant includes one or more of periodic acid, potassium periodate, and sodium periodate.

[0018] The second aspect of the present invention provides a method for preparing the hydrophilic rubber according to the first aspect, comprising the following steps:

[0019] S1, immersing the isoprene rubber or natural rubber in an aqueous solution of an epoxidation agent and carrying out reaction a; and then immersing the isoprene rubber or natural rubber in an aqueous solution of a strong oxidant and carrying out reaction b to obtain the modified rubber;

[0020] or immersing isoprene rubber or natural rubber in an aqueous solution containing an epoxidizing agent and a strong oxidizing agent, and carrying out reaction c to obtain the modified rubber;

[0021] S2, immersing the modified rubber in a hydrophilic polymer aqueous solution and carrying out a reaction d to obtain the hydrophilic rubber.

[0022] Preferably, the concentration of peroxide in the aqueous peroxide solution is 1 to 30 wt%. More preferably, the concentration of hydrogen peroxide in the aqueous hydrogen peroxide solution is 1 to 30 wt%. More preferably, the concentration of peracetic acid in the aqueous peracetic acid solution is 1 to 20 wt%. More preferably, the concentration of potassium persulfate in the aqueous potassium persulfate solution is 1 to 20 wt%.

[0023] Preferably, the concentration of the strong oxidant in the aqueous solution of strong oxidant is 0.5 to 20 wt %. More preferably, the concentration of potassium permanganate in the aqueous solution of potassium permanganate is 0.5 to 20 wt %. More preferably, the concentration of potassium periodate in the aqueous solution of potassium periodate is 1 to 10 wt %.

[0024] Preferably, the concentration of the hydrophilic polymer aqueous solution is 0.05 to 10 wt%. More preferably, the concentration of polyvinyl alcohol in the polyvinyl alcohol aqueous solution is 0.1 to 5 wt%. More preferably, the concentration of sodium polyacrylate in the sodium polyacrylate aqueous solution is 0.1 to 3 wt%. More preferably, the concentration of polyethylene oxide in the polyethylene oxide aqueous solution is 0.1 to 10 wt%. More preferably, the concentration of sodium hyaluronate in the sodium hyaluronate is 0.05 to 0.5 wt%.

[0025] Preferably, when the strong oxidant aqueous solution is a periodic acid oxidant, the composition of the strong oxidant aqueous solution also includes an acidic substance.

[0026] More preferably, the acidic substance is an inorganic acidic oxidant. Further preferably, the inorganic acidic oxidant is selected from one or more of potassium hydrogen persulfate, potassium persulfate, and sodium persulfate.

[0027] More preferably, the concentration of the acidic substance in the aqueous solution of the strong oxidant is 5 to 20 wt %.

[0028] Preferably, the pH value of the hydrophilic polymer aqueous solution is 2 to 5, more preferably 2 to 3. More preferably, the pH value is adjusted using dilute sulfuric acid, dilute hydrochloric acid, acetic acid or propionic acid.

[0029] Preferably, the reaction time of reaction a is 10 to 120 s; the reaction time of reaction b is 10 to 120 s; and the reaction time of reaction c is 10 to 120 s.

[0030] More preferably, the reaction time of reaction a is 20 to 40 s; the reaction time of reaction b is 40 to 80 s; and the reaction time of reaction c is 40 to 80 s.

[0031] Preferably, the reaction time of the reaction d is 5 to 30 seconds.

[0032] More preferably, the reaction time of the reaction d is 5 to 20 s.

[0033] Preferably, step S1 further comprises the following steps: after reaction b or reaction c is completed, washing the modified rubber with water, wherein the washing time is 3 to 10 seconds.

[0034] Preferably, step S2 further comprises the following steps: after reaction d is completed, the product is dried at a temperature of 80 to 120°C.

[0035] Preferably, the isoprene rubber or natural rubber is an isoprene rubber condom or a natural rubber condom.

[0036] More preferably, the method further comprises the following steps: putting the isoprene rubber condom or the natural rubber condom on the mold before dipping; and demoulding the condom after dipping.

[0037] The third aspect of the present invention provides use of the hydrophilic rubber of the first aspect in the preparation of contraceptive condoms, safety condoms or finger cots.

[0038] The beneficial effects of the present invention are:

[0039] (1) The present invention provides a hydrophilic rubber, including a modified rubber and a hydrophilic polymer coating, wherein the modified rubber and the hydrophilic polymer coating are complexed by hydrogen bonds or covalently grafted by ester bonds or ether bonds, wherein the hydrophilic polymer coating makes the covalent bonds less likely to be destroyed by small molecule solvents such as water molecules and alcohols, and the covalent bonds are beneficial to improving the stability and durability of the hydrophilic coating, and the two enable the rubber to continuously maintain hydrophilic lubricity.

[0040] (2) The hydrophilic polymer used in the hydrophilic rubber of the present invention has good biocompatibility, is non-irritating to the skin, and will not cause skin allergies when used externally.

[0041] (3) The hydrophilic rubber of the present invention can be applied to self-lubricating condoms. After the surface coating of the condom comes into contact with water, aqueous solution or body fluid, the surface friction coefficient of the condom can be greatly reduced. In addition, the coating has stronger adhesion than traditional self-lubricating condoms and can still provide low friction after multiple friction cycles.

[0042] (4) The present invention also provides a method for preparing a hydrophilic rubber, which does not require the use of an initiator, has no residual risk, and has a short production time, thereby enabling large-scale rapid preparation. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a water contact angle test diagram of the self-lubricating condom of Example 4;

[0044] Figure 2 This is the water contact angle test diagram of the bare cover. DETAILED DESCRIPTION

[0045] The present invention is further described in detail below through specific examples. The raw materials used in the following examples, unless otherwise specified, can be obtained from conventional commercial sources or prepared and separated by simple synthesis; the processes used, unless otherwise specified, are conventional processes in the art.

[0046] The bare condoms used in the following embodiments and comparative examples are natural rubber condoms produced by Guangzhou Wanfangjian Pharmaceutical Co., Ltd., without adding hydrophilic polymer coating, made of natural rubber, with specifications: width 48-49mm, length 178-180mm, thickness 50-55μm.

[0047] Example 1

[0048] This embodiment provides a hydrophilic rubber, specifically a self-lubricating condom, and the preparation method thereof is as follows:

[0049] 1. Solution preparation

[0050] Solution a1: 15% aqueous hydrogen peroxide solution;

[0051] Solution b1: an aqueous solution containing 10% potassium persulfate and 3% sodium periodate;

[0052] Solution c1: 2% polyvinyl alcohol (degree of alcoholysis 88%, molecular weight 180,000-200,000) aqueous solution (adjust pH to 2-3 with 0.1 mol / L dilute sulfuric acid);

[0053] Wherein, the concentration values ​​are all mass percentage concentrations;

[0054] 2. Rubber modification

[0055] The bare sleeve on the mold is immersed in solution a1 for 30 seconds, taken out, and then immersed in solution b1, kept for 60 seconds, taken out, and the surface of the bare sleeve is washed with running water for 5 seconds to obtain a modified rubber;

[0056] 3. Hydrophilic coating curing

[0057] The modified rubber was immersed in solution c1 and kept for 10 seconds. The condom was taken out and dried together with the mold in an oven at 80°C for 25 minutes. After drying, the condom was cooled and demoulded to obtain a self-lubricating condom.

[0058] Example 2

[0059] This embodiment provides a hydrophilic rubber, specifically a self-lubricating condom, and the preparation method thereof is as follows:

[0060] 1. Solution preparation

[0061] Solution a2: 10% peracetic acid aqueous solution;

[0062] Solution b2: an aqueous solution containing 15% potassium persulfate and 6% potassium periodate;

[0063] Solution c2: 1% sodium polyacrylate (molecular weight 4-5 million) aqueous solution (adjust pH to 2-3 with 0.1 mol / L dilute hydrochloric acid);

[0064] Wherein, the concentration values ​​are all mass percentage concentrations;

[0065] 2. Rubber modification

[0066] The bare sleeve on the mold is immersed in solution a2 for 30 seconds, taken out, and then immersed in solution b2, kept for 60 seconds, taken out, and the surface of the bare sleeve is washed with running water for 5 seconds to obtain a modified rubber;

[0067] 3. Hydrophilic coating curing

[0068] The modified rubber was immersed in solution c2, kept for 10 seconds, taken out, and the condom together with the mold was dried in an oven at 90° C. for 20 minutes. After drying, it was cooled and demoulded to obtain a self-lubricating condom.

[0069] Example 3

[0070] This embodiment provides a hydrophilic rubber, specifically a self-lubricating condom, and the preparation method thereof is as follows:

[0071] 1. Solution preparation

[0072] Solution a3: 10% potassium permanganate aqueous solution;

[0073] Solution b3: an aqueous solution containing 20% ​​potassium persulfate and 10% periodic acid;

[0074] Solution c3: 5% aqueous solution of polyethylene oxide (molecular weight 4-5 million) (pH adjusted to 2-3 with 0.5 mol / L acetic acid);

[0075] Wherein, the concentration values ​​are all mass percentage concentrations;

[0076] 2. Rubber modification

[0077] The bare sleeve on the mold is immersed in solution a3 for 30 seconds, taken out, and then immersed in solution b3, kept for 60 seconds, taken out, and the surface of the bare sleeve is washed with running water for 5 seconds to obtain a modified rubber;

[0078] 3. Hydrophilic coating curing

[0079] The modified rubber was immersed in solution c3, kept for 10 seconds, taken out, and the condom together with the mold was dried in an oven at 100°C for 15 minutes. After drying, it was cooled and demoulded to obtain a self-lubricating condom.

[0080] Example 4

[0081] This embodiment provides a hydrophilic rubber, specifically a self-lubricating condom, and the preparation method thereof is as follows:

[0082] 1. Solution preparation

[0083] Solution a4: 25% aqueous hydrogen peroxide solution;

[0084] Solution b4: an aqueous solution containing 5% potassium persulfate and 1% sodium periodate;

[0085] Solution c4: 0.2% sodium hyaluronate (molecular weight 1.8-2 million) aqueous solution (adjusted with 0.5 mol / L propionic acid to pH = 2-3);

[0086] Wherein, the concentration values ​​are all mass percentage concentrations;

[0087] 2. Rubber modification

[0088] The bare sleeve on the mold is immersed in solution a4 for 30 seconds, taken out, and then immersed in solution b4, kept for 60 seconds, taken out, and the surface of the bare sleeve is washed with running water for 5 seconds to obtain a modified rubber;

[0089] 3. Hydrophilic coating curing

[0090] The modified rubber was immersed in solution c4, kept for 10 seconds, taken out, and the condom together with the mold was dried in an oven at 120°C for 8 minutes. After drying, it was cooled and demoulded to obtain a self-lubricating condom.

[0091] Example 5

[0092] This embodiment provides a hydrophilic rubber, specifically a self-lubricating condom, and the preparation method thereof is as follows:

[0093] 1. Solution preparation

[0094] Solution b4: an aqueous solution containing 5% potassium persulfate and 1% sodium periodate;

[0095] Solution c4: 0.2% sodium hyaluronate (molecular weight 1.8-2 million) aqueous solution (adjusted with 0.5 mol / L propionic acid to pH = 2-3);

[0096] Wherein, the concentration values ​​are all mass percentage concentrations;

[0097] 2. Rubber modification

[0098] The bare sleeve on the mold is immersed in solution b4, kept for 60 seconds, taken out, and the surface of the bare sleeve is washed with running water for 5 seconds to obtain the modified rubber;

[0099] 3. Hydrophilic coating curing

[0100] The modified rubber was immersed in solution c4, kept for 10 seconds, taken out, and the condom together with the mold was dried in an oven at 120°C for 8 minutes. After drying, it was cooled and demoulded to obtain a self-lubricating condom.

[0101] Comparative Example 1

[0102] This comparative example provides a water-wettable condom, which is not modified compared to Example 4. The only difference from Example 4 is that it is not immersed in solution a4 and solution b4. The remaining steps are the same, that is, the bare condom on the mold is directly rinsed with running water and then the hydrophilic coating is cured.

[0103] Comparative Example 2

[0104] This comparative example provides a water-wettable condom, which is not modified with epoxy groups compared to Example 4. The only difference from Example 4 is that the condom is not immersed in solution a4, solution b4 is replaced by a 25% potassium permanganate aqueous solution, and is immersed in solution b4 for 100 seconds, and the other steps are the same.

[0105] Comparative Example 3

[0106] This comparative example provides a water-wet condom. Compared with Example 4, no strong oxidation modification is performed. The only difference from Example 4 is that solution b4 is replaced by a commercially available sodium hypochlorite solution containing 13-16% effective chlorine, and the other steps are the same.

[0107] Comparative Example 4

[0108] This comparative example provides a water-moisturizing condom. Compared with Example 4, which uses a low-concentration solution to modify the rubber, the only difference from Example 4 is that solution a4 is replaced by a 0.5% hydrogen peroxide aqueous solution, and solution b4 is replaced by an aqueous solution containing 0.5% potassium persulfate and 0.5% sodium periodate, and the remaining steps are the same.

[0109] Comparative Example 5

[0110] This comparative example provides a water-wettable condom, which reduces the modification time compared with Example 4. The only difference from Example 4 is that solution b4 is replaced by a 25% potassium permanganate aqueous solution, and the condom is immersed in solution a4 for 3 seconds and in b4 for 6 seconds, and the other steps are the same.

[0111] Performance Testing and Results

[0112] 1. Water contact angle, bursting capacity and bursting pressure test

[0113] The water contact angles of the self-lubricating condoms of Examples 1-5, bare condoms (bare condoms are condoms without any treatment, the same below) and Comparative Examples 1-5 were measured using a German Kruss DSA25 contact angle meter. Figure 1 This is a water contact angle test diagram of the self-lubricating condom of Example 4. Figure 2 This is the water contact angle test diagram of the bare cover, and the specific results are shown in Table 1;

[0114] Table 1

[0115]

[0116]

[0117] The bursting capacity and bursting pressure of the self-lubricating condoms and bare condoms of Examples 1-5 were tested according to GB / T 7544-2019 standard. The specific results are shown in Table 2:

[0118] Table 2

[0119]

[0120] From the data in Table 1 and Table 2, it can be seen that after hydrophilic modification, the water contact angle of the condom with hydrophilic coating curing has been greatly reduced, and the hydrophilicity of the condom surface has been greatly improved. At the same time, after accelerated aging test, the bursting capacity and bursting pressure of all samples meet the standards required by GB / T 7544-2019, indicating that the product condoms still have excellent durability and rupture resistance after hydrophilic modification, ensuring that there will be no safety risks caused by accidental rupture during use.

[0121] 2. Dynamic friction test

[0122] The dynamic friction coefficient of the condom samples and bare condoms prepared in Examples 1-5 was measured with reference to the method of GB 10006-2021. Specifically, the stainless steel mold with the condom was placed in a container filled with physiological saline (water temperature 37°C), and vertically fixed on a friction coefficient meter (test range 0-5 Newtons). At the same time, a rubber-coated clamp was used to apply a force of 2 Newtons to the condom surface on the stainless steel mold. When the mold movement speed was 150 mm / min, the clamp was reciprocated 500 times on the condom surface on the mold, and the single movement distance was 120 mm. The dynamic friction coefficient was measured, and the measurement results are shown in Table 3:

[0123] Table 3

[0124]

[0125] From the data in Table 3, it can be seen that the friction coefficient of the condoms with lubricating coating obtained in Examples 1-5 is relatively stable as the number of times increases during the cyclic sliding of the fixture, indicating that the coating is firm and rarely falls off, especially in Examples 4-5, the friction coefficient is still less than 0.1 after 300 cycles. The friction coefficient of the bare condoms without any treatment is much higher than that of the condoms with lubricating coating and they broke after about 150 cycles.

[0126] From the experimental data in Table 3, it can be seen that the product prepared by using sodium hyaluronate as the lubricating component in Example 4 has the best coating firmness. By comparing and analyzing the structural characteristics of the hydrophilic polymers used in the examples (see Table 4), it can be inferred that: under acidic conditions, during the heating and curing of the condom, the large amount of hydroxyl and carboxyl groups simultaneously contained in sodium hyaluronate are more likely to react with a certain amount of hydroxyl and carboxyl groups generated by oxidation treatment on the surface of the condom to form ester or ether, forming more covalent bond grafting effects, while polyvinyl alcohol only contains a large amount of hydroxyl groups, and polyethylene oxide only contains hydroxyl groups at the end positions. The conditions for these two polymers to form ether bonds with the newly formed hydroxyl groups on the surface of the condom are relatively difficult; sodium polyacrylate only contains a large amount of carboxyl groups and can form a certain amount of ester bonds. The four polymers all contain a large number of functional groups that can form hydrogen bonds: hydroxyl / carboxyl groups. In addition to covalent grafting, the coating molecules of the products obtained in the four examples also contain a large number of strong hydrogen bonds with the condom, which makes the hydrophilic polymer have a strong adhesion on the surface of the condom.

[0127] Table 4

[0128]

[0129]

[0130] The same method was used to measure the dynamic friction coefficient of the condom samples and bare condoms of Comparative Examples 1-5, and the reciprocating motion was reduced to 30 times. The test results are shown in Table 5:

[0131] Table 5

[0132]

[0133] The following conclusions can be drawn from the data in Table 5: (1) In Comparative Example 1, the condom surface was directly impregnated with a hydrophilic polymer solution without any oxidation treatment and then dried. Since the natural rubber surface of the condom lacks a large number of hydroxyl, carboxyl, carbonyl and other functional groups that can form strong hydrogen bonds and ether and ester formation, the hydrophilic polymer adhesion is very weak. After the fixture circulates 10 times, the hydrophilic polymer lubricating coating is basically completely detached; (2) In Comparative Example 2, when peroxide treatment is used instead of potassium persulfate / periodic acid compounds, insufficient peroxide bonds or hydroxyl groups are formed on the natural rubber surface of the condom, which is still difficult to By forming sufficiently strong hydrogen bonds and ether formation with the hydrophilic polymer, there is no carboxyl group to provide ester formation conditions. After the clamp is circulated for 20 times, the hydrophilic polymer lubricating coating is basically completely detached; (3) In comparative example 3, when the condom surface is pre-treated with peroxide and then other commonly used strong oxidants such as sodium hypochlorite are used, hydroxyl and chlorine can be formed on the surface of the natural rubber of the condom, but the key carboxyl group cannot be formed. The lubricating coating has obviously detached after the clamp is circulated for 30 times; (5) In comparative examples 4 and 5, when the concentration of the oxidizing solution used is too low and the immersion time is too short, the lubricating coating is very easy to fall off.

[0134] In summary, the combined treatment of the condom surface with an epoxidation agent and a strong oxidant can make the condom and the hydrophilic polymer combine well.

[0135] 3. Mechanical properties test

[0136] The self-lubricating condoms and bare condoms of Examples 1-5 were tested for tensile strength and elongation with reference to standard GB / T 7544-2019. The results are shown in Table 6:

[0137] Table 6

[0138]

[0139] The results in Table 6 show that the condoms of Examples 1-5 still have high tensile strength and elongation after hydrophilic modification and are not easily broken or damaged.

[0140] 4. Biological toxicity test

[0141] The condom samples obtained in Examples 1-5 and Comparative Examples 1-5 were tested according to the standards GB / T16886.5-2017 (Biological Evaluation of Medical Devices Part 5: In Vitro Cytotoxicity Test) and GB / T14233.2-2005 (Part 2: Biological Test Methods):

[0142] (1) Main materials and reagents:

[0143] Cell line: L929 mouse fibroblasts (Shanghai Institute of Cell Biology, Chinese Academy of Sciences), RPMI1640 culture medium (GIBCO), dimethyl sulfoxide (DMSO, Merrill), CO2 incubator (Therm HERA cell150i), inverted microscope (Nikon TE2000-U), constant temperature water bath.

[0144] Preparation of extract:

[0145] Sample group: According to GB / T 16886.12-2017, condom samples are 6cm 2 / mL, 4.5cm 2 / mL, 3cm 2 / mL, 1.5cm 2 / mL, 0.6cm 2 / mL, and placed at 37±1°C for 24h. The extraction medium is RPMI1640 medium containing 10% serum.

[0146] Negative group: High-density polyethylene, extracted at a ratio of 0.2 g / mL, under the same conditions as the sample group.

[0147] Positive group: natural rubber material, extracted with RPMI1640 medium containing 5% DMSO and 10% serum, the conditions were the same as the sample group.

[0148] Test method (microscope observation, according to GB / T14233.2-2005):

[0149] Set up blank group, negative group, positive group and sample group. After 72h of vigorous growth, L929 cells were digested and added into cell culture medium to prepare 1×10 5 / mL cell suspension, inoculated in a 6-well cell culture dish, 2mL per well. Each group operates 3 wells in parallel, and cultured in a CO2 incubator (37±1)℃ until the monolayer cells are 70% confluent. Discard the stock solution, add 2mL of the corresponding test solution (blank group, negative group, positive group, sample extracts of different concentrations) to each well, continue to culture in a CO2 incubator for 72h, and observe under a microscope.

[0150] It should be noted that according to the GB / T16886.5-2017 test, all extraction concentrations in the table need to be covered. Since the condoms tested are only coated with a single-sided hydrophilic coating, the uncoated side will be dissolved during the extraction, and the impurities such as protein brought in by natural rubber will inevitably affect cell growth, thus resulting in severe results.

[0151] (2) The experimental results are shown in Table 7:

[0152] Table 7

[0153]

[0154]

[0155] From the data in Table 7, it can be seen that the bare sleeve is not covered with a lubricating coating, and some harmful substances in the natural rubber are leached out. The coatings of Comparative Examples 1-5 have poor adhesion, and the coatings gradually fall off during the 24-hour leaching process. Then, some harmful substances in the natural rubber are leached out, which has a significant impact on cell growth and causes cytotoxicity.

[0156] Examples 1 to 5 are samples with a firm lubricating coating. Since the coating covers the rubber surface of one side of the condom sample, impurities harmful to cells will not be dissolved during extraction, so the test results are better than those of bare condoms. 2 / mL concentration, the reaction degree has been reduced from severe to moderate, and at 1.5cm 2 / mL and below concentration, non-toxic.

[0157] All examples and comparative samples of the present invention were also tested in accordance with the requirements of the standard GB / T 16886.10-2017 "Biological Evaluation of Medical Devices Part 10: Irritation and Skin Sensitization Test" and the standard GB 15979-2002 "Hygiene Standards for Disposable Hygiene Products". The test results show that all condoms meet the requirements of the above standards.

[0158] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A hydrophilic rubber, characterized in that: The invention comprises a modified rubber, the surface of which is covered with a hydrophilic polymer coating; the modified rubber is prepared by the following steps: using an epoxidation agent and a strong oxidant to treat isoprene rubber or natural rubber.

2. The hydrophilic rubber according to claim 1, characterized in that The material of the hydrophilic polymer coating is selected from one or more of polyvinyl alcohol, sodium polyacrylate, polyethylene oxide, and sodium hyaluronate.

3. The hydrophilic rubber according to claim 2, characterized in that The molecular weight of the polyvinyl alcohol is 170,000-220,000; the molecular weight of the sodium polyacrylate is 3 million-7 million; the molecular weight of the polyethylene oxide is 3 million-7 million; and the molecular weight of the sodium hyaluronate is 1.7 million-2.2 million.

4. The hydrophilic rubber according to claim 1, characterized in that The epoxidation reagent is selected from one or more of inorganic peroxides, organic peroxyacids, and inorganic peroxyacids; the strong oxidant is a permanganate oxidant or a periodate oxidant.

5. The hydrophilic rubber according to claim 4, characterized in that The organic peracid includes one or more of performic acid, peracetic acid, perbenzoic acid, meta-chloroperbenzoic acid, and peroxytrifluoroacetic acid; the inorganic peracid includes persulfuric acid; the inorganic peroxide includes one or more of hydrogen peroxide and potassium persulfate; the periodic acid oxidant includes one or more of periodic acid, potassium periodate, and sodium periodate.

6. The method for preparing the hydrophilic rubber according to any one of claims 1 to 5, characterized in that: The specific steps include: S1, immersing the isoprene rubber or natural rubber in an aqueous solution of an epoxidation agent and carrying out reaction a; and then immersing the isoprene rubber or natural rubber in an aqueous solution of a strong oxidant and carrying out reaction b to obtain the modified rubber; or immersing isoprene rubber or natural rubber in an aqueous solution containing an epoxidizing agent and a strong oxidizing agent, and carrying out reaction c to obtain the modified rubber; S2, immersing the modified rubber in a hydrophilic polymer aqueous solution and carrying out a reaction d to obtain the hydrophilic rubber.

7. The method for preparing the hydrophilic rubber according to claim 6, characterized in that: The concentration of the epoxidation reagent in the epoxidation reagent aqueous solution is 1 to 30 wt %; And / or, the concentration of the strong oxidant in the strong oxidant aqueous solution is 0.5-20wt%.

8. The method for preparing the hydrophilic rubber according to claim 6, characterized in that: The concentration of the hydrophilic polymer aqueous solution is 0.05-10 wt %.

9. The method for preparing the hydrophilic rubber according to claim 6, characterized in that: More preferably, the pH value of the hydrophilic polymer aqueous solution is 2 to 5; Preferably, the pH value of the hydrophilic polymer aqueous solution is adjusted using dilute sulfuric acid, dilute hydrochloric acid, acetic acid or propionic acid.

10. The method for preparing the hydrophilic rubber according to claim 6, characterized in that: When the strong oxidant aqueous solution is a periodic acid oxidant, the composition of the strong oxidant aqueous solution also includes an acidic substance.

11. The method for preparing the hydrophilic rubber according to claim 10, characterized in that: The acidic substance is an inorganic acidic oxidant; Preferably, the inorganic acidic oxidant is selected from one or more of potassium persulfate, potassium persulfate and sodium persulfate.

12. The method for preparing the hydrophilic rubber according to claim 6, characterized in that: The reaction time of reaction a, reaction b and reaction c is independently 10 to 120 seconds; And / or, the reaction time of the reaction d is 5 to 30 seconds.

13. The method for preparing the hydrophilic rubber according to claim 6, characterized in that: Step S1 also includes the following steps: after reaction b or reaction c is completed, the modified rubber is washed with water for 3-10 seconds.

14. Use of the hydrophilic rubber according to any one of claims 1 to 5 in the preparation of contraceptive condoms, safety condoms or finger cots.

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