阅读说明：本技术 一种抗菌聚氨酯弹性体及其制备方法 (Antibacterial polyurethane elastomer and preparation method thereof ) 是由 张兴光 王威 张瑾 鄢军 于 2020-05-27 设计创作，主要内容包括：本发明属于高分子复合功能材料技术领域,涉及一种抗菌聚氨酯弹性体及其制备方法。制备所述的抗菌聚氨酯弹性体的原料按质量配比包含：聚醚多元醇或聚酯多元醇100份,异氰酸酯32-62份,水1-4.5份,平均粒度为25-350nm的无机纳米抗菌剂0.3-2.5份。利用本发明的抗菌聚氨酯弹性体及其制备方法,能够更好的制备抗菌聚氨酯弹性体,制备所得聚氨酯弹性体能够达到更好、更持久、更均匀的抗菌效果,同时降低成本和减少对环境、人体的危害。(The invention belongs to the technical field of high-molecular composite functional materials, and relates to an antibacterial polyurethane elastomer and a preparation method thereof. The antibacterial polyurethane elastomer is prepared from the following raw materials in parts by mass: 100 parts of polyether polyol or polyester polyol, 32-62 parts of isocyanate, 1-4.5 parts of water and 0.3-2.5 parts of inorganic nano antibacterial agent with the average particle size of 25-350 nm. By utilizing the antibacterial polyurethane elastomer and the preparation method thereof, the antibacterial polyurethane elastomer can be better prepared, the prepared polyurethane elastomer can achieve better, more lasting and more uniform antibacterial effect, and meanwhile, the cost is reduced and the harm to the environment and human bodies is reduced.)

1. The antibacterial polyurethane elastomer is characterized by comprising the following raw materials in parts by mass: 100 parts of polyether polyol or polyester polyol, 32-62 parts of isocyanate, 1-4.5 parts of water and 0.3-2.5 parts of inorganic nano antibacterial agent with the average particle size of 25-350 nm.

2. The antibacterial polyurethane elastomer according to claim 1, wherein the raw materials for preparing the antibacterial polyurethane elastomer comprise, by mass: 100 parts of polyether polyol or polyester polyol, 32-62 parts of isocyanate, 2-4 parts of water and 0.5-1.7 parts of inorganic nano antibacterial agent with the average particle size of 30-100 nm.

3. The antibacterial polyurethane elastomer according to claim 1 or 2, characterized in that:

the polyether polyol or polyester polyol is selected from one or more of dihydroxy polyether polyol, trihydroxy polyether polyol and polyethylene glycol adipate, and the average relative molecular mass is 1000-6500;

the isocyanate is selected from one or more of toluene diisocyanate, diphenylmethane diisocyanate and polymethylene polyphenyl polyisocyanate;

the inorganic nanoThe rice antibacterial agent is selected from CuO, ZnO, TiO₂、SiO₂、WO₃One or more of them.

4. The antibacterial polyurethane elastomer according to claim 1 or 2, characterized in that: the raw materials for preparing the antibacterial polyurethane elastomer also comprise 0.1 to 2.0 parts of catalyst and/or 5 to 15 parts of foaming agent according to the mass ratio,

the catalyst is selected from one or more of triethylene diamine, pentaethylene tetramine, hexamethylene diamine and stannous octoate;

the foaming agent is selected from one or more of dichloromethane, fluorotrichloromethane, pentane and cyclopentane.

5. The antibacterial polyurethane elastomer according to claim 1 or 2, characterized in that: the inorganic nano antibacterial agent is an inorganic nano antibacterial agent subjected to surface hydrophobicity treatment by a surface modifier, a coupling agent and/or a surfactant, or an inorganic nano antibacterial agent subjected to ion exchange, impregnation loading, partial coating and covering and/or mechanical mixing and composite superposition.

6. The antibacterial polyurethane elastomer according to claim 1 or 2, characterized in that: the raw materials for preparing the antibacterial polyurethane elastomer also comprise 0.1-2.5 parts of foam stabilizer according to the mass ratio.

7. A method for preparing the antibacterial polyurethane elastomer according to any one of claims 1 to 6, wherein the method comprises the steps of:

(1) taking all or part of the polyether polyol or polyester polyol, adding the inorganic nano antibacterial agent, stirring and mixing, and then performing ultrasonic dispersion and mixing to obtain a dispersion liquid;

(2) adding the rest raw materials except the isocyanate into the dispersion liquid, further stirring and mixing, adding the isocyanate, and continuously stirring and mixing to obtain a mixed foaming liquid;

(3) and preparing the mixed foaming liquid into the polyurethane elastomer.

8. The method of claim 7, wherein: in the step (1), the step (c),

the stirring speed for stirring and mixing is 30-5000 r/min, and the time is 5-20 min;

the temperature of the ultrasonic dispersion mixing is 20-60 ℃, the power is 200-3000W, and the time is 5-100 minutes.

9. The method of claim 7, wherein: in the step (2),

the stirring speed for further stirring and mixing is 3000-6000 r/min, and the time is 1-120 min;

the stirring speed for continuously stirring and mixing is 3000-6000 r/min, and the time is 3-5 seconds.

10. The method of claim 7, wherein: and (3) transferring the mixed foaming liquid to a mixing head, and processing the mixed foaming liquid into the polyurethane elastomer through a conveying section, a foaming section, a cutting section, a post-curing section and a post-processing section of the product.

Technical Field

The invention belongs to the technical field of high-molecular composite functional materials, and relates to an antibacterial polyurethane elastomer and a preparation method thereof.

Background

Polyurethane elastomers, which are called Polyurethane (PU) in our country and Polyurethane internationally, are polymers having a high molecular structure and a large number of "urethane" structures (-NHCOO-) in the main chain.

Polyurethane elastomers are used in a wide variety of fields, for example in the automotive sector (seals, sleeves, leather, seals, decorative panels, etc.), the construction sector (concrete moulds, door seals, sand-blasting tubes, etc.), the coating fabrics (conveyor belts, synchronous belts, etc.), the electronics industry (packaging, insulators, circuit boards, electronic board coatings, etc.), the food industry (slide linings, cereal stores, conveyor belts, etc.), the mining industry (bucket linings, scrapers, pump linings, screens, etc.), the footwear industry (shoe soles, bottom-molded diaphragms, cushion insoles, etc.), sports (playing fields, runways, dumbbells, boats, etc.), coatings (interior and exterior wall coatings, color steel plates, household coatings, etc.), adhesives (adhesive tapes, highway sealants, etc.), the textile industry (floor mats, sofas, brassiere undergarments, cosmetic cotton, mattresses, etc.).

The main basic raw materials for preparing polyurethane elastomers are isocyanates and compounds containing active hydrogen. The active hydrogen-containing chemical is mainly polyester polyol or polyether polyol containing more than two terminal hydroxyl groups. The isocyanate and the compound containing active hydrogen are subjected to nucleophilic addition reaction under certain conditions to generate the polymer containing a carbamate structure (-NHCOO-). Different isocyanates and different active hydrogen compounds are selected, different auxiliary agents (such as a plasticizer, an antistatic agent, a release agent, a filling agent, a foaming agent, a foam stabilizer and the like) are added at the same time, and the polyurethane elastomers with different chemical properties and physical properties and different application fields are obtained under the action of a catalyst.

The polyurethane elastomer can be divided into polyester polyurethane elastomer and polyether polyurethane elastomer, and the polyester polyurethane elastomer is easy to grow bacteria and mould under the condition of moist heat, so that the physical properties of the polyurethane elastomer are rapidly reduced; although the polyether polyurethane elastomer has weak mildew-proof antibacterial capacity, once the temperature and the humidity are proper, bacteria and mold grow and propagate rapidly as well. Especially, the porous polyurethane elastomer is easy to face the problem of bacterial breeding, so that products such as insoles, mattresses, sofa cushions, ground mats and bra underwear in the textile which are directly contacted with a human body are easy to excessively breed bacteria, the performance of the products is reduced, peculiar smell is generated, and the health of the human body is directly threatened to a certain extent.

Therefore, the development of the polyurethane elastomer with high-efficiency antibacterial property is of great significance. The antibacterial agent is combined with the polyurethane elastomer, so that the polyurethane elastomer has the capability of inhibiting the growth and the reproduction of bacteria or killing the bacteria to lose the physiological activity, and the polyurethane elastomer is the antibacterial polyurethane elastomer.

There are some reports on the prior art regarding antimicrobial polyurethane elastomers.

For example, chinese patent application CN200610166477.2 discloses a photocatalyst antibacterial sponge and pillow and cushion products thereof, wherein the photocatalyst antibacterial sponge is prepared from the following components by the conventional process: TiO with crystal form of anatase₂The photocatalyst material has the pore number of more than 1200 meshes, and the addition amount is 1-8 percent of the polyether polyol; polyether polyols, wherein one has an average molecular weight of 400-; isocyanate with the trade name of TDI80/20 and the index of 85-115; amine catalyst, triethylene diamine, pentaethylene tetramine or hexamethylene diamine, the addition amount is 0.5-2% of polyether polyol; stannous octoate catalyst, the consumption is 0.1-1.5% of polyether polyol; the trade name of the foam stabilizer is L580, Y8002 or 8123, and the addition amount is 1-2%; foaming agent, water addition amount is 1-3% of polyether polyol.

For another example, chinese patent application CN200710008623.3 discloses a nano-antibacterial sponge and its processing technology, which is prepared from the following main raw materials: 90-110 parts of polyether polyol, 3-5 parts of nano antibacterial agent, 8-12 parts of external foaming agent, 4-6 parts of water, 1.25-1.7 parts of foam stabilizer, 0.4-0.60 part of catalyst and 56-68 parts of toluene diisocyanate. The preparation process comprises the steps of weighing the raw materials according to the weight ratio, firstly adding 3-5 parts of nano antibacterial agent into 100 parts of polyether polyol raw material to fully disperse the nano antibacterial agent in polyether, then sequentially adding 8-12 parts of external foaming agent, 4-6 parts of water, 1.25-1.75 parts of foam stabilizer and 0.4-0.6 part of catalyst, stirring to mix uniformly, then adding 56-68 parts of toluene diisocyanate, stirring for 3-5 seconds at a high speed of 3600 r/min, pouring the raw materials into a prepared box body (cylindrical or rectangular) to start foaming, wherein the foaming process is 60-140 seconds, and removing the raw materials from the box body after 15-20 minutes to obtain antibacterial sponge, processing the antibacterial sponge into lining for shoes with various specifications and shapes according to needs, wherein the nano antibacterial material in the sponge can be uniformly distributed in the sponge body, the nanometer material has slow releasing effect and can maintain the antiseptic and deodorizing functions for long time.

Also, for example, chinese patent application CN201710982208.1 discloses an antibacterial sponge and a preparation method thereof, the preparation method comprising: adding rhizoma Amorphophalli powder, antibacterial filler, foaming agent, wetting agent and gel into boiling water, and stirring to obtain material liquid M1; transferring the feed liquid M1 into a sponge embryo, standing at room temperature, and performing heat treatment to obtain an embryo; pricking a plurality of uniform holes on the blank, freezing, and finally carrying out vacuum freeze drying to obtain the antibacterial sponge; wherein the antibacterial filler is prepared by mixing tea, lime water, bamboo leaves, eucalyptus leaves, radix angelicae, fructus gardeniae, mangnolia officinalis, cortex phellodendri, sappan wood, radix ophiopogonis, folium isatidis, mint, schisandra chinensis, curcumol, citral and flavanthrone.

Also for example, chinese patent application CN201910439373.1 discloses an antibacterial sponge and a preparation method thereof, wherein the antibacterial sponge is prepared from a component a and a component b; the component A comprises the following components in parts by weight: PE 68000.2-1 part, PE 62001-2 parts, polyether silicone oil activator 0.1-0.5 part, 1000NI 1-2 parts, nano silver powder 0.5-1 part, wollastonite powder 35-50 parts and water 45-55 parts; and the component B is 45-55 parts of hydrophilic polyurethane prepolymer.

For another example, chinese patent application CN201910686248.0 discloses an antibacterial sponge and a preparation method thereof, wherein the antibacterial sponge comprises the following components in parts by weight: 95-105 parts of soft foam polyether polyol, 44.5-46.3 parts of toluene diisocyanate, 1.5-3 parts of antibacterial agent, 2.5-3.5 parts of water, 0.8-1.4 parts of organic silicon surfactant and 0.2-0.36 part of catalyst; wherein the antibacterial agent is VANQUISH 100.

However, the problems of the above-mentioned prior art antibacterial polyurethane elastomer include: limited antimicrobial effect, short effective antimicrobial time, high addition of antimicrobial agents, high price of antimicrobial agents or harmful.

Disclosure of Invention

The invention aims to provide an antibacterial polyurethane elastomer, so that the polyurethane elastomer can achieve better, more lasting and more uniform antibacterial effect with less addition of an antibacterial agent, and meanwhile, the cost is reduced and the harm to the environment and human bodies is reduced.

In order to achieve the purpose, in a basic embodiment, the invention provides an antibacterial polyurethane elastomer, and raw materials for preparing the antibacterial polyurethane elastomer comprise the following components in percentage by mass: 100 parts of polyether polyol or polyester polyol, 32-62 parts of isocyanate, 1-4.5 parts of water and 0.3-2.5 parts of inorganic nano antibacterial agent with the average particle size of 25-350 nm.

In a preferred embodiment, the present invention provides an antibacterial polyurethane elastomer, wherein the raw materials for preparing the antibacterial polyurethane elastomer comprise, by mass: 100 parts of polyether polyol or polyester polyol, 32-62 parts of isocyanate, 2-4 parts of water and 0.5-1.7 parts of inorganic nano antibacterial agent with the average particle size of 30-100 nm.

In a preferred embodiment, the present invention provides an antimicrobial polyurethane elastomer, wherein:

the polyether polyol or polyester polyol is selected from one or more of dihydroxy polyether polyol, trihydroxy polyether polyol and polyethylene glycol adipate, and the average relative molecular mass is 1000-6500;

the isocyanate is selected from one or more of toluene diisocyanate, diphenylmethane diisocyanate and polymethylene polyphenyl polyisocyanate;

the inorganic nano antibacterial agent is selected from CuO, ZnO and TiO₂、SiO₂、WO₃One or more of them.

In a preferred embodiment, the invention provides an antibacterial polyurethane elastomer, wherein the raw materials for preparing the antibacterial polyurethane elastomer further comprise 0.1-2.0 parts by mass of a catalyst (preferably 0.4-1.5 parts by mass of a catalyst) and/or 5-15 parts by mass of a foaming agent (preferably 8-12 parts by mass of a foaming agent),

the catalyst is selected from one or more of triethylene diamine, pentaethylene tetramine, hexamethylene diamine and stannous octoate;

the foaming agent is selected from one or more of dichloromethane, fluorotrichloromethane, pentane and cyclopentane.

In a preferred embodiment, the invention provides an antibacterial polyurethane elastomer, wherein the inorganic nano antibacterial agent is an inorganic nano antibacterial agent subjected to surface hydrophobicity treatment by a surface modifier, a coupling agent and/or a surfactant (for example, the inorganic antibacterial agent modified by a silane coupling agent KH570, the addition amount of KH570 is 0.5-20%, preferably 0.5-3% of the absolute dry mass of the inorganic antibacterial agent), or an inorganic nano antibacterial agent subjected to ion exchange, impregnation loading, partial coating and/or mechanical mixing and composite superposition (for example, the inorganic nano antibacterial agent subjected to TiO composite superposition) treatment (for example, the inorganic nano antibacterial agent subjected to surface hydrophobicity treatment by a TiO coupling agent KH570 is subjected to surface hydrophobicity treatment by a silane coupling agent KH570, or the inorganic nano antibacterial agent subjected to surface hydrophobicity treatment by a TiO exchange, impregnation loading, partial coating and/or mechanical mixing and composite superposition₂Exchanging the ion-exchangeable groups on the surface with silver and other ions to obtain Ag/TiO₂A composite antimicrobial agent; for another example: mixing SiO₂Combining with ZnO antibacterial agent, coating ZnO surface part to form more stable antibacterial agent with composite structure; for another example: ZnO antibacterial agent which is treated by surfactant such as sodium octadecyl sulfonate and improves the surface hydrophilicity of the nano particles).

In a preferred embodiment, the invention provides an antibacterial polyurethane elastomer, wherein the raw materials for preparing the antibacterial polyurethane elastomer further comprise 0.1-2.5 parts (preferably 0.5-1.5 parts) by mass of a foam stabilizer (for example, a series of Niax brand foam stabilizers supplied by Meiji advanced materials group (GE silicone in the original USA), DC198 and other brand foam stabilizers of Air Products company, and BYK chemical company, Germany).

The second purpose of the present invention is to provide a method for preparing the above-mentioned antibacterial polyurethane elastomer, so as to better prepare the above-mentioned antibacterial polyurethane elastomer, and the prepared polyurethane elastomer can achieve better, more durable and more uniform antibacterial effect, and at the same time, reduce cost and reduce harm to environment and human body.

To achieve this object, in a basic embodiment, the present invention provides a method for preparing the above antibacterial polyurethane elastomer, the method comprising the steps of:

(1) taking all or part of the polyether polyol or polyester polyol, adding the inorganic nano antibacterial agent, then stirring and mixing, and then carrying out ultrasonic dispersion and mixing to obtain a dispersion liquid (in a premixed liquid obtained by mechanical stirring, inorganic antibacterial agent powder can be dispersed in the polyether polyol or polyester polyol in a smaller aggregate form; in the ultrasonic dispersion process, the inorganic antibacterial agent with smaller aggregates is dispersed into single nano particles, so that the added inorganic antibacterial agent is uniformly dispersed in the polyether polyol or polyester polyol);

(2) adding the rest raw materials except the isocyanate into the dispersion liquid, further stirring and mixing, then adding the isocyanate, and continuously stirring and mixing to obtain a mixed foaming liquid (no special equipment is needed in the step, and the required high-speed stirring equipment is equipment commonly used in the production process of the polyurethane elastomer and is mixing equipment commonly used by polyurethane elastomer producers and technicians);

(3) and preparing the mixed foaming liquid into the polyurethane elastomer.

In a preferred embodiment, the present invention provides the above-mentioned method for preparing an antibacterial polyurethane elastomer, wherein in step (1),

the stirring speed of stirring and mixing is 30-5000 r/min (preferably 60-300 r/min), and the time is 5-20 min;

the temperature of the ultrasonic dispersion mixing is 20-60 ℃ (preferably 40-50 ℃), the power is 200-3000W, and the time is 5-100 minutes (preferably 30-60 minutes).

In a preferred embodiment, the present invention provides the above-mentioned method for preparing an antibacterial polyurethane elastomer, wherein in the step (2),

the stirring speed for further stirring and mixing is 3000-6000 r/min, and the time is 1-120 min;

the stirring speed for continuously stirring and mixing is 3000-6000 r/min, and the time is 3-5 seconds.

In a preferred embodiment, the present invention provides the above-mentioned method for preparing an antibacterial polyurethane elastomer, wherein in step (3), the mixed foaming solution is transferred to a mixing head, and then processed into a polyurethane elastomer through a conveying section, a foaming section, a cutting section, a post-curing section and a post-processing section of the product (refer to "handbook of polyurethane materials" second edition published by chemical industry press, xupelin, zhanghui).

The invention has the beneficial effects that the antibacterial polyurethane elastomer can be better prepared by utilizing the antibacterial polyurethane elastomer and the preparation method thereof, the prepared polyurethane elastomer can achieve better, more lasting and more uniform antibacterial effect, and simultaneously, the cost is reduced and the harm to the environment and human body is reduced.

The invention selects inorganic antibacterial agents ZnO and TiO with high safety₂And the like. Although the silver-containing antibacterial agent has a good antibacterial effect, the silver-containing antibacterial agent is high in price, is prone to color change along with the prolonging of time, has a certain potential safety risk after being accumulated in organisms, and can cause pollution to natural environments such as soil and water.

The inorganic antibacterial agent of the present invention has an average particle size of 25 to 350nm, preferably 30 to 100 nm; the inorganic antibacterial agent is added in an amount of 0.3 to 2.5 parts, preferably 0.5 to 1.7 parts, relative to 100 parts of the polyether polyol or polyester polyol. Therefore, the oven dry mass ratio of the inorganic antibacterial agent in the final product is below 1.0% and is 0.35-0.83%.

The inorganic antibacterial agent of the present invention can be dispersed more uniformly. As is well known, when the inorganic antibacterial agent is nano-particles, the inorganic antibacterial agent is easy to agglomerate to form large particles, and the agglomeration causes the reduction of antibacterial performance and the waste of the antibacterial agent; meanwhile, the performance of the polyurethane elastomer product is possibly reduced due to the overlarge agglomerated particles. Therefore, in order to exert high antibacterial activity, it is necessary to solve the stability and dispersibility of the nanoparticles. The invention adopts the technologies of high-speed mechanical stirring and ultrasonic dispersion to uniformly disperse the inorganic nano antibacterial agent in the polyether polyol or polyester polyol, so that the inorganic antibacterial agent in the finally obtained product is more uniformly dispersed and has high-efficiency antibacterial effect.

Detailed Description

The following examples further illustrate embodiments of the present invention.

Example 1: preparation of antibacterial polyurethane elastomer

(1) Accurately weighing all the required raw materials: 100g of polyether polyol (dihydroxy polyether polyol with average relative molecular mass of 1000), 32g of isocyanate (toluene diisocyanate), 0.4g of catalyst (triethylene diamine), 0.5g of foam stabilizer (NiaxL-533 which is a foam stabilizer of Mianji high-tech materials group), 8g of external foaming agent (dichloromethane), 2g of water and 0.5g of inorganic antibacterial agent. The inorganic antibacterial agent is nano ZnO without any surface modification, and the average grain diameter is 30 nm.

(2) Preparation of dispersion of inorganic antibacterial agent: 2g of polyether polyol is taken and 0.5g of inorganic antibacterial agent is added. Stirring the mixture for 20 minutes at 30 revolutions per minute in a stirrer to form a premix, and further dispersing the premix by using an ultrasonic disperser, wherein the ultrasonic dispersion conditions are as follows: the temperature is 60 ℃, the power is 200W, and the time is 100 minutes. The mixed solution obtained after mechanical stirring and ultrasonic dispersion is the dispersion solution of the inorganic antibacterial agent.

(3) Preparing a mixed foaming liquid: adding 98g of the rest polyether polyol into the dispersion liquid of the inorganic antibacterial agent obtained in the step (2), then sequentially adding an external foaming agent, water, a foam stabilizer and a catalyst, immediately stirring at 3000 rpm for 120 minutes, and uniformly mixing. And adding isocyanate after uniformly mixing, and continuously stirring at a high speed of 3000 r/min for 5 seconds to uniformly mix the isocyanate and the isocyanate to obtain the mixed foaming liquid.

(4) Foaming and subsequent processes of the polyurethane elastomer: and (4) immediately transferring the mixed foaming liquid obtained in the step (3) to a mixing head, and performing a conveying section, a foaming section, a cutting section, a post-curing section and a post-processing section of the product to obtain the antibacterial polyurethane elastomer.

Example 2: preparation of antibacterial polyurethane elastomer

(1) Accurately weighing all the required raw materials: 100g of polyether polyol (trihydroxy polyether polyol with the average relative molecular mass of 3000), 62g of isocyanate (diphenylmethane diisocyanate), 1.5g of catalyst (pentaethylenetetramine), 1.5g of foam stabilizer (DC 198 foam stabilizer from Air Products), 12g of external foaming agent (pentane), 4g of water and 1.7g of inorganic antibacterial agent. The inorganic antibacterial agent is nano CuO without any surface modification, and the average grain diameter is 100 nm.

(2) Preparation of dispersion of inorganic antibacterial agent: 10g of polyether polyol is taken, and 1.7g of inorganic antibacterial agent is added. Stirring the mixture for 5 minutes at 5000 revolutions per minute in a stirrer to form a premix, and further dispersing the premix by using an ultrasonic disperser, wherein the ultrasonic dispersion conditions are as follows: the temperature was 20 ℃, the power was 3000W, and the time was 5 minutes. The mixed solution obtained after mechanical stirring and ultrasonic dispersion is the dispersion solution of the inorganic antibacterial agent.

(3) Preparing a mixed foaming liquid: adding 90g of the rest polyether polyol into the dispersion liquid of the inorganic antibacterial agent obtained in the step (2), then sequentially adding the external foaming agent, water, the foam stabilizer and the catalyst, and immediately stirring at 6000 rpm for 1 minute for uniformly mixing. And adding isocyanate after uniformly mixing, and continuously stirring at a high speed of 6000 rpm for 3 seconds to uniformly mix the isocyanate and the isocyanate to obtain the mixed foaming liquid.

(4) Foaming and subsequent processes of the polyurethane elastomer: and (4) immediately transferring the mixed foaming liquid obtained in the step (3) to a mixing head, and performing a conveying section, a foaming section, a cutting section, a post-curing section and a post-processing section of the product to obtain the antibacterial polyurethane elastomer.

Example 3: preparation of antibacterial polyurethane elastomer

(1) Accurately weighing all the required raw materials: 100g of polyester polyol (polyethylene glycol adipate with the average relative molecular mass of 6500), 50g of isocyanate (polymethylene polyphenyl polyisocyanate), and catalyst (stannous octoate))1.0g of foam stabilizer (SILBYK-9231 foam stabilizer from BYK chemical company, Germany) 1.0g of external foaming agent (cyclopentane) 10g of water 3g of external foaming agent and 1.1g of inorganic antibacterial agent. The inorganic antibacterial agent is nano TiO modified by KH570 surface₂The addition amount of KH570 is absolutely dry nanometer TiO₂3% by mass of nano TiO₂The average particle size was 70 nm.

(2) Preparation of dispersion of inorganic antibacterial agent: 5g of polyester polyol is taken and 1.1g of inorganic antibacterial agent is added. Stirring the mixture for 10 minutes at 1000 revolutions per minute in a stirrer to form a premix, and further dispersing the premix by using an ultrasonic disperser, wherein the ultrasonic dispersion conditions are as follows: the temperature is 40 ℃, the power is 1500W, and the time is 45 minutes. The mixed solution obtained after mechanical stirring and ultrasonic dispersion is the dispersion solution of the inorganic antibacterial agent.

(3) Preparing a mixed foaming liquid: 95g of the remaining polyester polyol is added to the dispersion of the inorganic antibacterial agent obtained in the step (2), and then the external foaming agent, water, the foam stabilizer and the catalyst are sequentially added, and the mixture is immediately stirred at 4500 rpm for 60 minutes and uniformly mixed. After being mixed uniformly, the isocyanate is added, and the mixture is stirred at a high speed of 4500 rpm for 4 seconds to be mixed uniformly, so that the mixed foaming solution can be obtained.

(4) Foaming and subsequent processes of the polyurethane elastomer: and (4) immediately transferring the mixed foaming liquid obtained in the step (3) to a mixing head, and performing a conveying section, a foaming section, a cutting section, a post-curing section and a post-processing section of the product to obtain the antibacterial polyurethane elastomer.

Example 4: detection of antibacterial polyurethane elastomers

The antibacterial rate of the polyurethane elastomer obtained in examples 1 to 3 against escherichia coli and staphylococcus aureus was measured by the shaking method specified in GB/T20944.3-2008, and the results are shown in table 1 below.

TABLE 1 results of tests of antibacterial ratio of polyurethane elastomers obtained in examples 1 to 3

0.5kg of each of the polyurethane elastomers obtained in examples 1 to 3 was washed in a common household washing machine for 10 times according to the standard procedure, and then the antibacterial rates of the polyurethane elastomers against escherichia coli and staphylococcus aureus were measured according to the shaking method specified in GB/T20944.3-2008, with the results shown in table 2 below.

TABLE 2 results of tests of antibacterial ratio after washing 10 times for polyurethane elastomers obtained in examples 1 to 3

The results in table 2 show that the antibacterial polyurethane elastomer still has good antibacterial effect after 10 times of washing.