Thermosensitive condom based on waterborne polyurethane and preparation method thereof
阅读说明：本技术 一种基于水性聚氨酯的热敏安全套及其制备方法 (Thermosensitive condom based on waterborne polyurethane and preparation method thereof ) 是由 叶恒 刘灯旺 谭遂丹 于 2020-07-29 设计创作，主要内容包括：本发明提供了一种基于水性聚氨酯的热敏安全套及其制备方法。所述热敏安全套的制备方法包括：(1)以聚酯二醇、低分子量聚醚二元醇和高分子量聚醚二元醇作为软段,二异氰酸酯和扩链剂作为硬段,发生预聚反应,并经过扩链反应、交联反应,以及乳化过程得到聚氨酯水乳液；其中,所述低分子量聚醚二元醇的数均分子量为400～1000,高分子量聚醚二元醇的数均分子量为2000～5000,聚酯二醇的用量占水乳液中固体总重量的百分比不高于5％；(2)将聚氨酯水乳液通过模具浸渍成型,卷边干燥和脱膜,制得热敏安全套。本发明的热敏安全套在体温附近所具有的模量较低,产品柔软,体感舒适度高,彻底消除异物感,又具有优异的拉伸强度,能够确保安全,不易破损。(The invention provides a thermosensitive condom based on waterborne polyurethane and a preparation method thereof. The preparation method of the thermosensitive condom comprises the following steps: (1) taking polyester glycol, low molecular weight polyether glycol and high molecular weight polyether glycol as soft segments, and diisocyanate and a chain extender as hard segments, carrying out prepolymerization reaction, and carrying out chain extension reaction, crosslinking reaction and emulsification to obtain a polyurethane aqueous emulsion; wherein the number average molecular weight of the low molecular weight polyether glycol is 400-1000, the number average molecular weight of the high molecular weight polyether glycol is 2000-5000, and the amount of the polyester glycol accounts for no more than 5% of the total weight of solids in the aqueous emulsion; (2) and (3) carrying out dip forming on the polyurethane aqueous emulsion through a die, curling, drying and demoulding to obtain the thermosensitive condom. The thermosensitive safety sleeve disclosed by the invention has the advantages of lower modulus near body temperature, soft product, high body feeling comfort level, capability of thoroughly eliminating foreign body feeling, excellent tensile strength, capability of ensuring safety and difficulty in damage.)
1. A preparation method of a thermosensitive condom based on waterborne polyurethane is characterized by comprising the following steps:
(1) preparation of aqueous polyurethane emulsion:
taking low molecular weight polyether diol, high molecular weight polyether diol and polyester diol as soft segments, taking diisocyanate and a chain extender as hard segments, carrying out prepolymerization reaction according to the isocyanate index NCO/OH ratio of 1.1-1.5, and carrying out chain extension reaction, crosslinking reaction and emulsification process to obtain polyurethane aqueous emulsion; wherein the number average molecular weight of the low molecular weight polyether glycol is 400-1000, the number average molecular weight of the high molecular weight polyether glycol is 2000-5000, and the amount of the polyester glycol accounts for not more than 5% of the total weight of solids in the polyurethane aqueous emulsion;
(2) forming the heat-sensitive condom:
and (2) preparing the aqueous emulsion of polyurethane obtained in the step (1) into a soaking solution, performing dip molding through a mold, and performing curling drying and demolding to obtain the thermosensitive condom based on the waterborne polyurethane.
2. The method according to claim 1, wherein the prepolymerization in step (1) comprises the steps of: firstly, mixing low molecular weight polyether diol, high molecular weight polyether diol and polyester diol, heating to 90-120 ℃, carrying out vacuum dehydration for 2-3 hours, then cooling to 50-70 ℃, adding diisocyanate, carrying out prepolymerization reaction at 70-90 ℃ for 1-2 hours.
3. The method according to claim 1 or 2, wherein a catalyst is further added during the prepolymerization in step (1), wherein the catalyst is at least one selected from tin-based catalysts, amine-based catalysts and organobismuth catalysts, and is used in an amount of 0.01 to 0.1% by weight based on the total weight of the solids in the aqueous emulsion of polyurethane.
4. The preparation method according to claim 1, wherein the chain extension reaction in step (1) comprises a chain extension reaction performed by adding a chain extender B1 and/or a chain extender B2 after the prepolymerization reaction is finished; and/or adding a chain extender B3 in the prepolymerization process for chain extension reaction; and/or adding chain extenders B4 and/or B5 into water for chain extension reaction in the emulsification process;
preferably, the chain extender B1 is diol with the molecular weight of less than 300, and the using amount of the chain extender B1 accounts for 1-5% of the total weight of solids in the polyurethane aqueous emulsion; preferably, the chain extender B1 is at least one selected from ethylene glycol, 1, 3-propylene glycol, 1, 4-butanediol, neopentyl glycol, 1, 6-hexanediol, 1, 4-cyclohexanedimethanol, diethylene glycol and tetraethylene glycol;
preferably, the chain extender B2 is a hydrophilic chain extender, and the chain extender B2 is at least one selected from dimethylolpropionic acid, dimethylolbutyric acid, tartaric acid, N-dihydroxy monomaleamic acid, sodium 1, 2-propanediol-sulfonate, sodium 1, 4-butanediol-2-sulfonate, diethanolamine, N-methyldiethanolamine, N-dimethyldiethanolamine, and quaternary ammonium cationic compounds containing hydroxyl functional groups;
preferably, the chain extender B3 is a nonionic hydrophilic chain extender, and the number average molecular weight of the chain extender B3 is more than or equal to 500; preferably, the chain extender B3 is a glycol chain extender with a side chain containing a hydrophilic polyethylene glycol chain segment, and the chain extender B3 is composed of trimethylolpropane polyethylene glycol monomethyl ethers with different molecular weights and is selected from at least one of mer-N120, mer-N180 and mer-N90;
preferably, the chain extender B4 is a water-soluble diamine compound and comprises at least one of ethylenediamine, 1, 3-propylenediamine, 1, 4-butylenediamine, 1, 5-pentylenediamine, 1, 6-hexylenediamine, isophorone diamine, lysine methyl ester and lysine ethyl ester, and the amount of the chain extender B4 is 0.03-1% of the total weight of solids in the aqueous polyurethane emulsion;
preferably, the chain extender B5 is a hydrophilic chain extender and is selected from at least one of lysine, ethylenediamine ethanesulfonic acid sodium salt, ethylenediamine propanesulfonic acid sodium salt, 2, 4-diaminobenzene sulfonic acid sodium salt and quaternary ammonium cationic compound containing amino functional groups;
preferably, the chain extenders B2, B3 and B5 are all hydrophilic chain extenders, at least one of the hydrophilic chain extenders B2, B3 and B5 is selected during chain extension, and the total amount of the hydrophilic chain extenders B2, B3 and B5 accounts for 2-8% of the total weight of solids in the aqueous emulsion of polyurethane.
5. The method according to claim 1, wherein the crosslinking reaction in step (1) is carried out by adding a crosslinking agent in an amount of 0.03 to 5% by weight based on the total weight of solids in the aqueous polyurethane emulsion; the cross-linking agent is a compound containing a plurality of active functional groups, and the active functional groups comprise at least one of hydroxyl, amine and sulfhydryl;
preferably, the crosslinking reaction in step (1) includes a crosslinking reaction of small molecule polyol after the prepolymerization reaction is finished; and/or, the crosslinking reaction of the macromolecular polyhydric alcohol is carried out simultaneously in the prepolymerization reaction process; and/or, carrying out a crosslinking reaction of the polyamino compound during the emulsification process; wherein the small molecule polyol comprises trihydric and/or tetrahydric alcohol, and the molecular weight of the small molecule polyol is not higher than 500; the macromolecular polyol is trihydric alcohol, and the molecular weight of the macromolecular polyol is not lower than 500; the polyamine-based compound comprises a triamine-based compound and/or a tetramine-based compound;
preferably, the crosslinking agent in step (1) includes at least one of trihydroxy compound, tetrahydroxy compound, triamino compound, tetramino compound, polyester triol and polyether triol; preferably at least one of trimethylolpropane, pentaerythritol, diethylenetriamine, triethylene tetramine, trihydroxy polycaprolactone and polyether triol;
preferably, in the step (1), an organic solvent is further added for dilution and viscosity reduction during the chain extension reaction and the crosslinking reaction, wherein the organic solvent comprises acetone, butanone or dimethyl carbonate; acetone is preferred.
Preferably, the emulsification process in step (1) is performed by a conventional preparation method of aqueous polyurethane emulsion, including but not limited to acetone method, prepolymer dispersion method or end-capped-NCO emulsification method, preferably acetone method or prepolymer dispersion method; the time of the emulsification process is 1-2 hours, then the organic solvent is removed, and the solid content of the final aqueous emulsion is 15-40%;
preferably, a neutralizing agent is further added before or during the emulsification process in step (1), wherein the neutralizing agent comprises at least one of alkali metal hydroxide, alkali metal bicarbonate, alkali metal carbonate, tertiary amine and an acid solution, and specifically comprises at least one of sodium hydroxide, potassium hydroxide, triethylamine, N-diisopropylethylamine, triethanolamine, N-dimethylethanolamine and glacial acetic acid solution; the amount of the neutralizing agent is 0-10% of the total weight of the solid in the polyurethane aqueous emulsion.
6. The method according to claim 1, wherein the low molecular weight polyether glycol in step (1) is a mixture of one or more; the high molecular weight polyether glycol is one or a mixture of more; the low molecular weight polyether diol and the high molecular weight polyether diol are both selected from at least one of polytetrahydrofuran ether glycol, polyethylene oxide ether glycol and polypropylene oxide ether glycol, and are preferably polytetrahydrofuran ether glycol;
preferably, the polyester diol in step (1) comprises at least one of polyester diol based on ethylene glycol-adipic acid, polyester diol based on 1, 4-butanediol-adipic acid, polyester diol based on ethylene glycol and 1, 4-butanediol and adipic acid, polyester diol based on neopentyl glycol-adipic acid, polyester diol based on 1, 6-hexanediol-adipic acid, polyester diol based on bio-based small molecule diol-acid, polycaprolactone diol or polycarbonate diol, and the number average molecular weight of the polyester diol is 600 to 4000, preferably 1000, 2000 or 3000;
in another preferred embodiment, the diisocyanate in step (1) is at least one selected from the group consisting of alicyclic diisocyanate, aliphatic diisocyanate and aromatic diisocyanate, and is preferably at least one selected from the group consisting of isophorone diisocyanate, hexamethylene diisocyanate, lysine-derived diisocyanate, m-xylylene isocyanate, toluene diisocyanate, diphenylmethane diisocyanate, 4-dicyclohexylmethane diisocyanate, trimethyl 1, 6-hexamethylene diisocyanate and cyclohexanedimethylene diisocyanate.
7. The preparation method according to claim 1, wherein the step (2) comprises the following specific steps:
s1: diluting the aqueous emulsion of polyurethane, adding an auxiliary agent into the aqueous emulsion of polyurethane to prepare an aqueous polyurethane condom dip forming adhesive emulsion;
s2: cleaning the glass mold, drying at 105 deg.C for 5-10min, and cooling to 40-50 deg.C; immersing a glass mold into the prepared aqueous polyurethane condom dipping molding glue emulsion, and dipping for multiple times to obtain an aqueous polyurethane glue film on the surface of the mold;
s3: and (3) performing edge curling treatment and drying on the surface adhesive film of the die, cooling, leaching by hot water at 55 +/-5 ℃, drying, impregnating silicon dioxide for isolation, drying in an oven at the temperature of 110-125 ℃ for 3-5min, and demolding to obtain the thermosensitive condom, thereby obtaining a thermosensitive condom finished product.
Preferably, the auxiliary agent in the S1 step in the step (2) includes an antifoaming agent, and the antifoaming agent is at least one selected from a polyether antifoaming agent, a silicone antifoaming agent, and a polyether modified silicon antifoaming agent.
8. A heat-sensitive condom based on waterborne polyurethane, characterised in that it is prepared by a process according to any one of claims 1 to 7.
9. The heat-sensitive condom of claim 8, wherein the heat-sensitive condom has a glass transition between 30-50 ℃ and no melting peak between 60-200 ℃.
10. The heat-sensitive condom of claim 8, wherein the heat-sensitive condom exhibits a temperature softening characteristic at 30-50 ℃;
preferably, the temperature softening characteristics specifically include: the temperature-sensitive condom has the modulus reduction rate of 10-20% when the deformation reaches 100% when the temperature is increased from 23 ℃ to 37 ℃; when the deformation reaches 300%, the modulus reduction rate is 15% -40%; but the tensile strength retention rate exceeds 90 percent, and the elongation at break is increased by 5 to 15 percent.
Technical Field
The invention belongs to the technical field of contraceptives, and particularly relates to a thermosensitive condom based on waterborne polyurethane and a preparation method thereof.
Background
Condom is a non-drug type pregnancy-preventing mode, is the most common contraceptive tool in the world, and is originally released in 1974 in China[1]. According to incomplete statistics, the consumption of condoms in China is nearly 120 hundred million each year. Condoms are currently not only tools for birth control, but are also one of the most effective methods for preventing the spread of sexually transmitted diseases. Along with the rapid spread of sexually transmitted diseases such as AIDS, the work situation of preventing and treating AIDS is increasingly severe, people have more and more demands on condoms, and along with the progress of society, people have more and more pursuits on the comfort and the safety of condom products, and the quality of condom products is also more and more valued by manufacturers.
Conventional condoms are typically made from natural latexNatural latex is obtained from the rubber tree. The natural latex has simple production process, easy gelatinization, easy vulcanization and good film forming property; the product has the advantages of large elasticity, good flexibility, small creep, excellent comprehensive performance and small influence on human bodies, so the product has unique excellent performance in the aspect of producing condoms. The natural latex condom has a long history, and the natural rubber production technology is developed by the Goodya corporation in 1840, the rubber condom made of natural rubber is pushed to the market, and the natural rubber condom is produced in 1909 in Japan[2]. Until now, the main raw material for producing condoms is still natural latex, and latex condoms still occupy a large market.
However, natural latex condoms have disadvantages, including low thermal conductivity, low tensile strength at break, susceptibility to oxidation, and poor oil and solvent resistance. In addition, natural latex also contains many non-rubber components such as allergic water-soluble protein and other biological macromolecules, which are easy to cause allergic reactions such as erythema and pruritus on the skin of users, and even many severe allergic patients can generate life-threatening convulsion and shivering. Statistically, about 8% of the population are allergic to natural latex products. Natural latex medical and health products have caused frequent allergic episodes in humans since the
In addition, the natural crack of the natural latex is 5000-[4]. In addition, a stabilizer for the surface of natural latex particles and a latexThe water-soluble substances in the latex have poor compatibility with latex, and in the dipping film-forming process, the substances are not dissolved in the latex film and are distributed in the film material in a micro-area mode, and in the subsequent process, the water-soluble substances are extracted by water to leave micropores on the surface of the natural latex condom film. A large amount of statistical data and research results prove that the traditional natural latex condom can generate certain barrier effect on viruses while effectively contraception, but has higher failure rate, particularly has no barrier capability on viruses such as HPV (human papilloma virus), HIV (acquired immune deficiency syndrome virus), HBV (hepatitis B virus) and the like, and is not beneficial to disease control[2]. Meanwhile, the condom is produced by taking natural latex as a raw material through vulcanization treatment, nitrosamine is generated in the process of vulcanization of the natural latex, and the substance has strong carcinogenicity. It is affected by various oil-based lubricants, and when condoms are used, carcinogens come into contact with human body fluids, and the resulting nitrosamines alkylate DNA, with the risk of eventually causing cancer.
On the other hand, the natural latex safety sleeve has the defects in manufacturing the ultrathin safety sleeve. A study in the united states has shown that the sensitivity of men increases by 20% for every 10 μm reduction in thickness. The natural latex is limited by the performance, 36 μm is the thickness limit, although some select natural latex in specific producing area to prepare condom with 30 μm, the natural latex in specific producing area has limited resource, and the natural latex in Chinese climate environment cannot produce the high quality natural latex[5]. The natural latex condom has the disadvantages of low strength, poor thermal conductivity, poor toughness of a condom film, special smell, easy induction of anaphylactic reaction and the like, is sensitive to heat, humidity and ultraviolet light, has low aging resistance, is easily influenced by various oil-based lubricants in the storage process, and easily reduces the physical properties of products.
To summarize, latex condoms suffer mainly from the following problems: (1) water soluble proteins cause allergic problems; (2) the virus barrier rate caused by natural cracks is low; (3) nitrosamines are at risk of inducing cancer; (4) low strength, poor thermal conductivity, and low toughness.
Polyurethane condom products have come into the hands because of the above-mentioned problems with latex condoms. Since the 90 s of the 20 th century, a novel polyurethane condom was developed for the first time, the research and development of condoms have also been rapidly changed, and latex condoms are increasingly replaced by polyurethane condoms. The polyurethane condom is suitable for people sensitive to rubber, has the characteristics of no toxicity, high strength, good heat conductivity, good toughness of condom film, no special smell, no anaphylactic reaction and the like, is not sensitive to heat, humidity and ultraviolet light, has good aging resistance, is not influenced by various oil-based lubricants in the storage process, can not greatly reduce the physical properties of products, can effectively prevent contraception and filter AIDS virus and the like, and is a safe and comfortable condom[4]。
Polyurethane (PU for short) refers to a polymer material containing repeated urethane bonds (-NHCOO-) in the molecular structure, and is a short name for polyurethane. In the polyurethane structure, hard chain segments and soft chain segments are alternately distributed in a polymer chain, and the soft chain segments are derived from diol and are responsible for the elastic property of the polymer; the hard segments are derived from the rigid components of the isocyanate and chain extender and bear the mechanical properties of the polyurethane, such as repulsion elasticity, film-forming ability and abrasion resistance, etc.
The polyurethane has the advantages of wide adjustable range of soft and hard sections, low temperature resistance, good flexibility, strong adhesive force and the like, and has the excellent qualities of high elasticity, wear resistance, oil resistance, aging resistance, corrosion resistance, tear resistance, radiation resistance, good compatibility and the like. Polyurethane shows great performance difference of various products due to flexible and various adjustment modes and different component selection and preparation modes, for example, products made of polyurethane comprise foamed plastics, elastomers, coatings, adhesives, fibers, synthetic leather and the like, various products have unique performance requirements, the polyurethane is widely applied to the electromechanical, ship, light industry and textile departments, products and varieties made of polyurethane show a trend of increasing year by year, the polyurethane is an advanced high polymer material with great application value, and the polyurethane is a novel material with the largest variety, the widest application and the fastest development in modern high polymer materials at present.
The performance of polyurethane is influenced by many factors, such as the type and molecular weight of soft segment polymer diol, the type of isocyanate, the type of chain extender, crosslinking density, reaction process, processing temperature and the like, and the performance of the obtained product can be greatly different as long as the formula is slightly different; the properties of the obtained product can generate obvious difference according to different synthesis methods[6]. Therefore, these factors should be considered in the structural design and modification of polyurethane. As a typical block polymer, the distribution of soft and hard segments in the main chain is also an important factor affecting the properties of the polyurethane.
Because of the unique characteristics of polyurethane, the polyurethane film can be well used for preparing film products, and the polyurethane film products can be used for manufacturing condoms through corresponding stretching, casting and dipping processes, so that the production requirements of the condom film can be met.
Polyurethanes are a class of polar polymeric materials, and widely used solvents are: polar organic solvents such as dimethylformamide, tetrahydrofuran, butanone, ethyl acetate, toluene and the like. The organic solvent causes pollution to the human living environment, influences the health of people and increases the use cost of polyurethane. Solvent type polyurethane dipping forming is tried to produce condom, and the process has the advantages of low relative molecular mass of polyurethane prepolymer, low viscosity of prepolymer solution and capacity of obtaining ultrathin thin-wall material of 25 micron, and has the disadvantages of great influence of curing condition on the performance of thin-wall material and difficult control[5]。
Commercial polyurethane condoms, which are typically made from thermoplastic polyurethane elastomeric rubber (TPU) or solvent-based polyurethane, have appeared in the 90 s of the 20 th century. Although the condoms have a history of about 30 years, the condoms belong to the products of the young, and the market share is extremely low. The forming method has certain requirements on TPU materials, thick-film TPU materials are stretched into thin-wall materials, the mechanical properties of the materials are required, and the materials are low in hardness and difficult to operate practically. After the film material is stretched, the film material is shaped, molecular chains are oriented, although the material can be greatly improvedThe tensile strength and the tear resistance of the material are improved by several times, the modulus of the material is improved, the hardness of the condom is higher, the elongation at break of the material is reduced, and the plastic feeling of the film is enhanced. The TPU film needs to be heat-sealed after being cut, the film is too soft and is difficult to process and form, heat sealing seams exist, the burr feeling is obvious, and the TPU film is not suitable for being used as a condom[5]。
In summary, although polyurethane has many advantages, there are problems of high modulus, high hardness and low elongation at break when preparing condoms, and the soft comfort of polyurethane still has a larger space for improving compared with latex condoms, and the currently produced polyurethane condoms are commercially in consideration of ultra-thin thickness, and often require high strength and toughness to ensure the use safety and be not easy to break, so that the elasticity and modulus of the material are difficult to reduce, which is more different from the soft comfort of latex condoms, and the feeling of use of people is poor, resulting in that the current solvent type polyurethane condoms have already exited the market.
In order to solve the above-mentioned disadvantages of solvent polyurethane condoms, Waterborne Polyurethane (WPU) materials have come into force. WPU is relative to solvent type polyurethane, and is a binary colloid system with polyurethane particles dispersed in a continuous phase (water), wherein water is used as a dispersion medium instead of an organic solvent, and the system does not contain or contains a small amount of the organic solvent. With the restriction of environmental regulations of various countries on the discharge amount of Volatile Organic Compounds (VOC) and the attention on environmental protection, WPU has been developed rapidly, has been widely applied in the fields of fabric, leather, adhesive and the like, and is gradually replacing solvent type polyurethane.
WPU is a block copolymer formed from a flexible polyol and rigid domains containing urethane groups, which are polar and capable of hydrogen bonding, thus imparting special properties to the polymer. The WPU has the advantages of good wear resistance, elasticity, flexibility, adhesive force, excellent low-temperature impact resistance, low VOC content, energy conservation, environmental protection and the like, but has the defects of poor water resistance of a coating film, unsatisfactory performances in the aspects of emulsion stability, self-thickening property, solid content and the like, and low mechanical strength, so that the WPU is used for aqueous solutionThe condom made of polyurethane has lower strength and tensile fracture rate[7]. Generally, the performance of WPU is affected by many factors, such as the segmented structure, the content of ionic groups, the molecular weight of polyol, the type of chain extender and the ratio of hard segment to soft segment, wherein the composition and chain length/structure of the soft segment are greatly affected, and the WPU performance is seriously affected by the amount of hydrophilic monomer, the interaction between ions and counter ions.
Compared with a natural latex condom, the condom made of the waterborne polyurethane has the advantages of high strength, compact structure, no holes, better virus resistance and the like, and can be ultrathin 0.01-0.03 mm in thickness, and more comfortable experience feeling and heat conduction speed are provided compared with the traditional natural latex condom in thinness. But the production process of the waterborne polyurethane condom puts high requirements at present.
The thin-wall material and the thin-wall product prepared by the waterborne polyurethane are always the dream of waterborne polyurethane researchers, but the mechanical property of the waterborne polyurethane is difficult to meet the requirement of the thin-wall material on the mechanical property. The thin-wall material is different from paint and adhesive, has no support of base material, and its mechanical property completely depends on the water-thinned polyurethane, and the thin-wall products such as operation gloves and condoms, etc. need low modulus, high tensile strength, high resilience and low permanent deformation, and these properties are all the weak items of water-thinned polyurethane material[5]。
Research reports on the preparation of condoms from waterborne polyurethanes have been very rare, although Sadowski reported earlier in 1978 that waterborne polyurethanes can be used to obtain thin-walled materials by coagulation impregnation[7]However, there are few reports on the dip forming of aqueous polyurethane. Until the Japanese ultrathin aqueous polyurethane condom is highly on the market, the Japanese phase-mode rubber industry released an aqueous polyurethane condom with a thickness of 20 μm in 2005 and 10 μm in 2013 and 12 months. 10 μm aqueous polyurethane condoms were also introduced in japanese oka book at 4 months in 2015. However, referring to Japanese patent, only Okangben published 2 patents on waterborne polyurethane condom in 2002[8-9]These 2 patents were introduced many years earlier than their products and essentially have no reference value. The water-based polyurethane condom technology is strictly kept secret and is difficult to find useful reference documents[5]. China has carried out research and development work on waterborne polyurethane condoms in a unit, but the research and development work fails due to raw material limitation and process difficulty[6]. In recent years, although related patent applications and products of the waterborne polyurethane condom are launched in China, the defects of high modulus, hardness and flexibility of the polyurethane condom are not really solved.
Although the waterborne polyurethane condom is popular, the 10-micron waterborne polyurethane condom released by the rubber industry of the phase model in 12 months in 2013 has an emergency production stop condition after a while because the user has strong plastic feeling of the condom, the modulus and hardness are too high to exceed the ideal indexes[5]。
Research shows that the breakage rate and the slippage rate of the waterborne polyurethane condom in the current market are respectively 7.2% and 3.6%, which are far higher than the breakage rate and the slippage rate of the natural latex condom by 1.1% and 0.6%, because the waterborne polyurethane condom in the current market has higher elastic modulus and lower softness than the natural latex condom[6]。
The core of producing the waterborne polyurethane condom is to prepare waterborne polyurethane which meets the performance requirement of the condom, and the condom has extremely high performance requirement on the waterborne polyurethane, and requires low modulus, high tensile strength, high tear strength, high resilience and low permanent deformation. Especially, for trying to prepare condom with 10 μm thickness, the requirement for mechanical property of water-based polyurethane dry film is more severe. The condom has the touch feeling similar to skin due to low modulus, the condom is prevented from being damaged in the using process due to high tensile strength and tearing strength, the condom is prevented from falling off in the using process due to high resilience and low permanent deformation, the strength of the condom is ensured to be maintained in the using process due to water resistance, and the shelf-life storage stability of a product is ensured due to aging resistance[5]. However, the effects are difficult to achieve by both latex condoms and waterborne polyurethane condoms at present.
Although latex condom and polyurethane condom products are still the main products in the market for condom production, at present, serious defects still exist. The problems of anaphylaxis, virus obstruction, strength and the like of the latex condom can not be solved; the polyurethane condom can have the problems that the latex condom cannot achieve high virus resistance and high strength, but the modulus is high, the hardness is high, the elongation at break is low, the softness, comfort and body feeling of materials are poor compared with those of latex, the low modulus, high heat conduction and high body feeling of the polyurethane condom are difficult to ensure at the same time, and the polyurethane condom has the characteristics of high tensile strength, high tearing strength, high resilience and high tensile strength.
In view of the foregoing, there is a trend to select polyurethane condoms to replace latex condoms due to the disadvantages of latex condoms. How to solve the above-mentioned not enough in performance that adopt polyurethane preparation condom product to exist among the prior art, guarantee that polyurethane condom has higher intensity and toughness, the elasticity of its material can be guaranteed simultaneously, and the modulus can not be too high, becomes the technical problem that awaits measuring to solve. Therefore, how to reduce the modulus of the polyurethane condom, ensure the softness and the elasticity of the polyurethane condom, reduce the hardness of the polyurethane condom, improve the softness to increase the body feeling, ensure the excellent mechanical strength of the polyurethane condom, ensure the polyurethane condom not to be damaged and become a new direction to be researched at the present stage.
Disclosure of Invention
Under the above background, the present invention provides a thermosensitive condom based on waterborne polyurethane and a preparation method thereof, aiming at solving the above performance deficiencies of the existing condom product, and solving the problems of high modulus, high hardness, poor softness and comfort of the existing waterborne polyurethane condom, and reducing the modulus and hardness of the polyurethane condom, and simultaneously reducing the strength of the polyurethane condom greatly and easily damaged.
One of the purposes of the invention is to provide a preparation method of a thermosensitive condom based on waterborne polyurethane, which comprises the following steps:
(1) preparation of aqueous polyurethane emulsion:
taking low molecular weight polyether diol, high molecular weight polyether diol and polyester diol as soft segments, taking diisocyanate and a chain extender as hard segments, carrying out prepolymerization reaction according to the isocyanate index NCO/OH ratio of 1.1-1.5, and carrying out chain extension reaction, crosslinking reaction and emulsification to obtain polyurethane aqueous emulsion; wherein the number average molecular weight of the low molecular weight polyether glycol is 400-1000, the number average molecular weight of the high molecular weight polyether glycol is 2000-5000, and the amount of the polyester glycol accounts for not more than 5% of the total weight of solids in the polyurethane aqueous emulsion;
(2) forming the heat-sensitive condom:
and (2) preparing the aqueous emulsion of polyurethane obtained in the step (1) into a soaking solution, performing dip molding through a mold, and performing curling drying and demolding to obtain the thermosensitive condom based on the waterborne polyurethane.
The applicant of the invention firstly carries out repeated research on soft and hard segment raw materials and a preparation process of the used polyurethane through a large amount of experimental groceries in order to reduce the modulus of the polyurethane and simultaneously solve the problem of insufficient mechanical strength of a water-based polyurethane film, and finally creatively discovers that the soft segment composition of the polyurethane is jointly adjusted by taking various macromolecular diol components of low molecular weight polyether diol, high molecular weight polyether diol and polyester diol of the invention as soft segments of the water-based polyurethane and by using two polyether diols with different molecular weights and a third component polyester diol, so that the degree of hydrogen bond action in the structure of the soft and hard segments of the polyurethane is adjusted, the phase structure of the polyurethane is influenced, and the obtained polyurethane material can show special changes in mechanical properties before and after being heated. According to the raw material proportion of the invention and the method, the inventor prepares the waterborne polyurethane condom product, and can well meet the production and use requirements of a special film of a condom. Particularly, the waterborne polyurethane condom produced by the invention has the advantages of low modulus near body temperature, soft product, high body feeling comfort level, capability of thoroughly eliminating foreign body feeling, excellent tensile strength, safety guarantee and difficult damage.
On the other hand, the applicant surprised that the waterborne polyurethane condom prepared by adopting the process of the invention shows unique heat-sensitive characteristics, which are shown as follows: the performance of the composite material at room temperature (15-25 ℃) shows the characteristics of slightly high modulus and excellent tensile strength, and the composite material can be used for preparing condoms of various types such as ultrathin condom products, and is easy to crimp, produce and wear; and exhibits a softening phenomenon when its temperature is raised to the body temperature. For example, when the temperature is increased from 23 ℃ to 37 ℃, the modulus reduction rate is 10-20% when the deformation reaches 100%; when the deformation reaches 300%, the modulus reduction rate is 15% -40%, meanwhile, the tensile strength retention rate exceeds 90%, and the elongation at break is increased by 5-15%.
This finding has significant advantages over other polyurethane condom products. Specifically, the invention does not solve the problems of high modulus and high hardness of polyurethane products by adopting new synthetic raw materials, but through the selection and the proportion of the specific raw material components, the polyurethane condom prepared according to the invention is unexpectedly found to have the unique heat-sensitive characteristic, the hardness and the modulus of the polyurethane condom can be reduced at the body temperature, and simultaneously, the polyurethane condom can be well ensured to be softened and can basically keep the original tensile strength. The modulus is greatly reduced, the polyurethane condom has excellent strength and elasticity, is not easy to damage, is safer and more comfortable to use, fundamentally solves the problem that the polyurethane condom always puzzles people, solves the problem that the polyurethane condom cannot reduce the hardness and the modulus when pursuing ultrathin thickness, and has the thermosensitive characteristic which is shown, so that the polyurethane condom is a thermosensitive condom in the true sense.
The heat-sensitive condom well overcomes the defects of the existing polyurethane condom, and the heat-sensitive property well solves the contradiction that the tensile strength of the polyurethane condom is difficult to maintain when the polyurethane condom pursues low modulus and high resilience; the modulus is difficult to decrease while high tensile strength is sought. On one hand, the problems of strong plasticity, insufficient soft comfort and relatively poor body feeling caused by high modulus of the common polyurethane condom are well solved, the higher comfort of the common polyurethane condom near the body temperature is ensured, and the body feeling of a user is greatly improved; on the other hand, the strength of the polyurethane condom is well ensured while the condom is softened, so that the condom is not easy to damage and has high use safety.
The inventor searches keywords of polyurethane or PU, waterborne polyurethane or water borne polyurethane, condom or condom condoms, and Thermosensitive condom or Thermosensitive condoms on various search websites, wherein the search websites relate to CNKI, Web of science, Google academic, Chinese patent information search System (SIPO), USPTO, JPO, EPO, WIPO and Derwent Innovation Index, reports of Thermosensitive condoms are not found, and the currently related polyurethane condom products do not show the report of the Thermosensitive characteristics of the invention, so the Thermosensitive condom belongs to the first creation, it has unique property, and the property solves the problem which is always desired to be solved by people to prepare the polyurethane condom at present, the problem that the tensile strength is difficult to maintain when people seek low modulus and high resilience is solved; the modulus is difficult to reduce while high tensile strength is pursued. The thermosensitive condom can realize the characteristics of low modulus, high resilience and high tensile strength.
Because of the unique heat-sensitive characteristics exhibited by the polyurethane condoms produced according to the present invention, which are now discovered for the first time, the inventors have given the following definitions to the heat-sensitive condom products referred to in the present invention: under the stimulation of the body temperature of a human body, the modulus of a condom product can be obviously reduced, but the tensile strength of the condom product can be basically kept unchanged, the elongation at break of the condom product can be moderately improved, and the soft comfort and the safety of difficult damage of the condom product are considered.
Since the heat-sensitive condom of the invention is the first creation, the prior patent or literature does not relate to the concept of the heat-sensitive condom. In order to facilitate a deeper understanding of the nature of the heat sensitive condom defined by the present invention, the applicant has illustrated the smart materials reported in the art as an entry point to show the essential distinction.
In the existing report, a temperature-sensitive biomaterial (referred to as a "temperature-sensitive material" for short) is mentioned, and under the stimulation of external environments such as temperature, magnetic field and the like, the solution is affected by the system acting force to generate phase change, so that the hydrogel is changed into semisolid gel, and the volume of the gel is changed. Compared with the traditional material, the temperature-sensitive material has good biocompatibility, low cytotoxicity and degradability, has more excellent performance and plays an important role in the sustained and controlled release of the medicine.
Shape memory polyurethanes are a representative class of temperature sensitive materials with broad shape recovery temperatures, high recoverable strain (up to 400%), and good biophysical properties. It can have properties of controlling transition temperature including glass transition temperature (Tg) or melting temperature (Tm) and the like by appropriately selecting the component composition of polyurethane. Wherein the hard segments act as stable polymer network phases, determining the permanent shape of the material while providing mechanical strength; the soft segment is then responsible for controlling the fixation and recovery of the shape under a specific external stimulus as a reversible switching phase.
Although the concept of the thermosensitive condom can change the performance of the material under the temperature response with the shape memory polyurethane introduced above, the two concepts are fundamentally different, the molecular structure regulation and control means of the invention is greatly different from the shape memory polyurethane, and the performance of the two products is greatly different. Specifically, the shape memory material is a material which can be used to fix and shape the product by some means during the processing process and can recover the shape under the special stimulus from the outside. If the thermotropic shape memory polymer is deformed at the state of exceeding the transformation temperature, the shape of the thermotropic shape memory polymer can be fixed at the temperature of being lower than the transformation temperature after the thermotropic shape memory polymer is deformed, the shape of the thermotropic shape memory polymer can be kept unchanged for a long time, and the thermotropic shape memory polymer can be restored to the original shape after the thermotropic shape memory polymer is heated to the transformation temperature. The thermosensitive condom does not need shape fixation at low temperature, and does not require the material to have a shape recovery function, so the thermosensitive condom does not belong to shape memory materials in the prior art. The polyurethane material can directly show the characteristics of high strength and high modulus of the polyurethane material at room temperature, and is convenient to process and produce. When the temperature reaches the body temperature, the temperature softening characteristic shown by the polyurethane material can obviously reduce the modulus of the polyurethane material, greatly improve the softness and comfort of the polyurethane material, even approach the degree of latex, well maintain the strength of the polyurethane material and moderately improve the elongation at break. The unique heat-sensitive characteristic of the material well solves the problems of the polyurethane condom, and is a heat-sensitive condom with unique temperature softening characteristic which is really pioneered for the field of condoms.
Drawings
FIGS. 1 and 2 are graphs showing DSC measurements of first temperature rise (temperature range-25-215 ℃) of samples of examples and comparative examples;
FIGS. 3-6 are graphs showing the changes in morphology at 0min and 3min after the addition of PBS buffers at 23 ℃ and 37 ℃ for the samples of the examples and the comparative examples, respectively;
wherein, the left panels A in the figures 3-6 all represent the topography of the sample at 0min after adding the PBS buffer solution with different temperatures, and the right panels B in the figures 3-6 all represent the topography of the sample at 3min after adding the PBS buffer solution with different temperatures.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is described in detail below with reference to the following embodiments, and it should be noted that the following embodiments are only for explaining and illustrating the present invention and are not intended to limit the present invention. The invention is not limited to the embodiments described above, but rather, may be modified within the scope of the invention.
For convenience of presentation, the following designations are used in the formulations of the examples and are hereby incorporated: PTMG-PBA-bis (polybutylene adipate-glycol)Polyols, PCDL ═ polycarbonate diols, PCL ═ polycaprolactone diols, PTHF CO 1000 ═ 1000 molecular weight special liquid polyethers, IPDI ═ isophorone diisocyanate, HMDI ═ dicyclohexylmethane diisocyanate, XDI ═ m-xylylene isocyanate, HDI ═ hexamethylene diisocyanate, MDI ═ diphenylmethane diisocyanate, H ═ hexamethylene diisocyanate6XDI ═ hydrogenated xylylene diisocyanate BDO ═ 1, 4-butanediol, HDO ═ 1, 6-hexanediol, NPG ═ neopentyl glycol, DMPA ═ 2, 2-dimethylolpropionic acid, VESTAMINA95 ═ ethylenediamine ethanesulfonic acid sodium, N120 ═ trimethylolpropane polyethylene glycol monomethyl ether, TMP ═ trimethylolpropane, CAPA3091 and CAPA3051 are all trihydroxy polycaprolactones, N-330 ═ trihydroxy polyether.
In addition, it is worth noting that the catalysts selected for use in the following examples include: the organobismuth compound catalyst is a bismuth carboxylate mixture: BiCAT8118 (advanced chemicals, USA); the organotin catalyst mainly comprises dibutyltin dilaurate: TMG218 (high schmidt). Examples selected defoamers for use include: polyether modified silicon defoamer AT-320F (field chemical), polyether defoamers B406 and B105 (Federal), and silicone defoamer KM-72GS (shiner chemical).
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