CN113801465B - Polyurethane microcellular foamed elastomer, and preparation method and application thereof - Google Patents

Abstract

The invention relates to the field of polyurethane foam for shoes, in particular to a polyurethane microcellular foaming elastomer and a preparation method and application thereof. The polyurethane microcellular foaming elastomer is prepared from the following components in parts by weight: 40-60 parts of polyester polyol, 30-40 parts of isocyanate, 0.1-1 part of foaming agent, 0.1-1 part of catalyst, 0.5-5 parts of chain extender, 0.1-1 part of polyurethane plasticizer, 0.1-1 part of foam stabilizer and 0.1-2 parts of graphene oxide loaded silver nanoparticles. The obtained polyurethane microporous foamed elastomer can effectively improve the tear resistance and the tensile property of the polyurethane elastomer, and can also improve the antibacterial property of the polyurethane elastomer.

Description

Polyurethane microcellular foaming elastomer and preparation method and application thereof

Technical Field

The invention relates to the field of polyurethane foam for shoes, in particular to a polyurethane microcellular foaming elastomer and a preparation method and application thereof.

Background

Polyurethane is a new type of organic multifunctional material, which is a generic name of macromolecular polymers with a-NHCOO-repeating structural unit prepared by chemical reaction of isocyanate and polyalcohol. 1952. The German Bayer company develops the polyester type soft polyurethane foam plastics and the corresponding continuous production equipment to produce the novel material with light specific gravity and high specific strength. The polyester type soft polyurethane foam plastic has the advantages of good strength, oil resistance, solvent resistance and oxidation resistance.

Due to the above advantages, the microporous elastomer of the polyester type is widely introduced in the research of the sole material. The research of the polyurethane microporous elastomer applied to the shoe sole starts in the early 60 s, and is put into industrial production in the early 70 s, and the yield of the polyurethane shoe sole in the south and north america, western europe and japan reaches about 12 ten thousand tons in the 80 s. Meanwhile, the production of polyurethane soles is increasing worldwide, and thus polyurethane microcellular elastomer foams are widely used in various footwear such as sports shoes, sneakers, sandals, slippers, and the like. The sole made of the polyurethane microporous foam has the following advantages: (1) Excellent wear resistance and flexibility resistance, high tear strength and long service life; (2) The rubber has excellent oil resistance, chemical resistance, cold resistance and good skid resistance; (3) The specific gravity of the sole is only 0.5-0.6 mg/m ³ The whole shoe achieves the purposes of portability, comfort, ventilation and sanitation; (4) The heat insulation material has good heat insulation performance, good heat insulation performance in winter and no sultriness in summer. Although the polyester type polyurethane foam has good mechanical property and rebound resilience, the polyester type polyurethane foam has certain polarity, so that bacteria are easy to breed. Thus, the use of polyurethane foam materials in shoe soles is also limited.

Disclosure of Invention

In order to improve the defects of the prior art, the invention provides a polyurethane composition, which comprises the following components in parts by weight:

40-60 parts of polyester polyol, 30-40 parts of isocyanate, 0.1-1 part of foaming agent, 0.1-1 part of catalyst, 0.5-5 parts of chain extender, 0.1-1 part of polyurethane plasticizer, 0.1-1 part of foam stabilizer and 0.1-2 parts of oxidized graphene loaded silver nanoparticles.

According to the embodiment of the invention, the graphene oxide of the silver nanoparticle loaded by the graphene oxide has a single-layer sheet structure, the thickness is 1-2nm, oxygen-containing functional groups such as hydroxyl and carboxyl are loaded on the surface of the graphene oxide, and the loaded silver particle has a nano structure, and the size of the silver particle is controlled to be 2-200 nm.

According to the embodiment of the invention, the weight part of the silver nanoparticles loaded on the graphene oxide silver is 0.1-1.5 parts, and preferably 0.15-1 part.

According to an embodiment of the present invention, the polyester polyol is a polymer prepared by polycondensation of a polyhydric alcohol and a dibasic acid or an anhydride thereof, wherein the dibasic acid may be at least one selected from adipic acid, pimelic acid, suberic acid, glutaric acid, sebacic acid, oxalic acid, succinic acid, phthalic anhydride, isophthalic anhydride, maleic anhydride, and the like; the polyhydric alcohol is at least one selected from ethylene glycol, propylene glycol, butanediol, diethylene glycol, triethylene glycol, 1, 6-hexanediol, neopentyl glycol, glycerol, pentaerythritol, sorbitol, polycaprolactone polyol, polypropylene carbonate polyol and the like.

According to an embodiment of the present invention, the molar ratio of alcoholic hydroxyl groups and carboxyl groups in the raw materials for preparing the polyester polyol is (1.02 to 1.2): 1.

according to a preferred embodiment of the invention, the polyester polyol is selected from Lupraphen H422.

According to an embodiment of the invention, the number average molecular weight of the polyester polyol is from 1000 to 2500g/mol.

According to a preferred embodiment of the invention, the polyester polyol is present in an amount of 45 to 55 parts by weight.

According to an embodiment of the present invention, the isocyanate is selected from diisocyanates or polyisocyanates, for example from toluene diisocyanate, diphenylmethane diisocyanate, polyphenylmethane polyisocyanate, 1, 5-naphthalene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, p-phenylene diisocyanate, tetramethylxylylene diisocyanate or derivatives of the aforementioned diisocyanates or polyisocyanates, and the like. According to a preferred embodiment of the invention, the isocyanate is chosen from Pasteur, CS 7319/106C-B.

According to an embodiment of the invention, the isocyanate is 30-35 parts.

According to an embodiment of the invention, the blowing agent is water, dichloromethane or a mixture thereof.

According to an embodiment of the present invention, the catalyst is a tertiary amine compound or an organometallic catalyst, wherein the tertiary amine compound is selected from triethylamine, N, N-dimethylhexadecylamine, diethylenetriamine, dimethylbenzylamine, N, N, N ', N ' -tetramethylmethylenediamine, bis (2-methylaminoethyl) ether, triethylenediamine, N-methylmorpholine, N-ethylmorpholine, N-2-hydroxypropyl dimethylmorpholine, N ' -diethyl-2-methylpiperazine, triethanolamine, pyridine, lutidine, tetramethylbutanediamine, triethylenediamine; the organic metal catalyst is selected from stannous octoate, dibutyltin dilaurate and the like.

According to an embodiment of the present invention, the chain extender is a hydroxyl or amino group-containing low molecular weight multifunctional alcohol compound selected from 1, 4-Butanediol (BDO), 1, 6-hexanediol, glycerol, trimethylolpropane, diethylene glycol (DEG), triethylene glycol, neopentyl glycol (NPG), sorbitol, diethylaminoethanol (DEAE), hydroquinone-bis (. Beta. -hydroxyethyl) ether (HQEE), or the like; the amine compound is selected from MOCA (3, 3' -dichloro-4, 4-diamino-diphenylmethane) and liquid MOCA modified with formaldehyde, ethylenediamine (DA), N-dihydroxy (diisopropyl) aniline (HPA), etc., for example, from ethylene glycol.

According to an embodiment of the present invention, the polyurethane plasticizer is selected from at least one of aromatic carboxylic acid ester (such as benzoate, dibutyl phthalate), aliphatic carboxylic acid ester or phosphate.

According to the embodiment of the present invention, the foam stabilizer is selected from substances which can reduce surface tension, such as silicone oil (AK 8807).

In the present invention, graphene oxide and graphene oxide-supported silver nanoparticles may be prepared according to methods known in the art. Graphene oxide can be prepared, for example, by the method described in section 2.2 of the references M-rGO-ZnNi-LDH extended WEP nanocomposites, effects of nanosheets on the mechanical and thermal properties, composites Part A, applied Science and Manufacturing,124, (2019) 105480.

According to the embodiment of the invention, the graphene oxide-loaded silver nanoparticles are prepared by the following method:

a) Preparation of graphene oxide

Dissolving graphite in concentrated sulfuric acid in an ice bath to form a suspension, adding potassium nitrate, stirring, and adding potassium permanganate after stirring; reacting for 1-12 hours at 20-45 ℃; after the reaction is finished, adding water (preferably deionized water) into the system, and stirring and reacting for 1-10 hours at the temperature of 0-10 ℃; finally, adding hydrogen peroxide and deionized water into the reaction system; washing the product to be neutral by using a weak acid solution;

b) Preparation of graphene oxide-loaded silver nanoparticles

And (2) dissolving the graphene oxide prepared in the step in water (preferably deionized water) and performing ultrasonic dispersion to form a suspension, then adding protease and silver nitrate solution, stirring at 30-40 ℃, reacting in a dark room, and performing centrifugal separation to obtain the graphene oxide-loaded silver nanoparticles.

According to an embodiment of the invention, the protease is selected from pepsin (e.g. porcine pepsin), papain, trypsin, cathepsin, subtilisin and the like, preferably porcine pepsin.

The invention also provides a polyurethane microcellular foamed elastomer which comprises the polyurethane composition.

In one embodiment, the polyurethane microcellular foamed elastomer is prepared by foaming and crosslinking the polyurethane composition described above.

The invention also provides a preparation method of the polyurethane microcellular foaming elastomer, which comprises the following steps:

stirring and ultrasonically dispersing polyester polyol, a foaming agent, a polyurethane plasticizer, a foam stabilizer, a catalyst, a chain extender, graphene oxide-loaded silver nanoparticles and isocyanate, and then foaming and crosslinking.

According to an embodiment of the invention, the frequency of the stirring is 8000 to 12000 revolutions per minute.

Preferably, the method comprises the steps of:

(1) Dispersing the graphene oxide-loaded silver nanoparticles in a mixture of a foaming agent and polyester polyol, and performing ultrasonic treatment to obtain a uniformly dispersed suspension;

(2) Adding a foam stabilizer, a catalyst and a chain extender into the step (1), and stirring and mixing at a high speed;

(3) Adding isocyanate into the system in the step (2), stirring at a high speed, quickly and uniformly mixing, introducing into a pre-prepared mold coated with a release agent, tightly covering, and foaming and forming;

(4) And after the mixture is completely reacted and the mold is removed, putting the prepared sample into an oven to be cured for 1 to 12 hours at the temperature of between 60 and 110 ℃ to obtain the polyurethane microcellular foamed elastomer.

According to the embodiment of the invention, in the step (3), a specially-made stirring paddle is adopted, the outer wall of the stirring paddle is circular, the upper part of the stirring paddle is provided with teeth, and the stirring paddle can be used for quickly and uniformly mixing high-viscosity resin without damaging the cup wall of the mixing container.

According to an embodiment of the present invention, in the step (2), the release agent is at least one selected from the group consisting of surfactant-based release agents such as silicone-based release agents, wax-based release agents, oil-and-fat-based release agents, fluorine-based release agents, and inorganic release agents, for example, at least one selected from the group consisting of silicone oil, silicone ester, silicone varnish, vegetable wax (carnauba wax) and mineral wax (FT wax), synthetic wax (polyethylene wax), animal fat (whale oil), petroleum-based fat (vaseline), perfluoroalkyl compounds, perfluoroalkyl acrylates, fluororesin powder (low molecular weight polytetrafluoroethylene), fluororesin coating film (PTFE, FEP, PFA), talc, mica, and clay.

The invention also provides the application of the polyurethane microcellular foamed elastomer as a polyurethane foam sole, and particularly relates to the application of the polyurethane microcellular foamed elastomer in manufacturing a polyurethane sole for upper-connected injection-molded shoes.

Advantageous effects

The invention provides a polyurethane microporous foaming elastomer and a preparation method and application thereof, aiming at solving the problems that the existing polyurethane microporous foam generally has no antibacterial function, lower mechanical property and poorer tear resistance. The polyurethane microporous foamed elastomer can effectively improve the tear resistance and the tensile property of the polyurethane elastomer, and can also improve the antibacterial property of the polyurethane elastomer. In addition, the silver nanoparticles loaded on the graphene oxide in the polyurethane microporous foamed elastomer are prepared by reducing and adsorbing silver ions in silver nitrate on the surface of the graphene oxide through a pepsin reduction method, and the reduced silver nanoparticles can be uniformly distributed on the surface of the graphene oxide, so that the silver nanoparticles are not easy to agglomerate, and the effects of resisting bacteria and improving mechanical properties are better.

Drawings

FIG. 1 is a tensile curve of the materials prepared in example 1 and comparative example 1.

Fig. 2 is an antibacterial effect test of the materials prepared in example 1 and comparative example 1.

Detailed Description

The technical solution of the present invention will be further described in detail with reference to specific embodiments. It is to be understood that the following examples are only illustrative and explanatory of the present invention and should not be construed as limiting the scope of the present invention. All the technologies realized based on the above-mentioned contents of the present invention are covered in the protection scope of the present invention.

Unless otherwise specified, the raw materials and reagents used in the following examples are all commercially available products or can be prepared by known methods.

In the description of the present invention, it is noted that the tensile strength test procedure is carried out in accordance with the standard of GB/T6344-2008. The test procedure for elongation at break is carried out with reference to GB/T6344-2008. The antibacterial test was carried out according to standard QB/T2881-2013.

Example 1

Preparing the graphene oxide-loaded silver nanoparticles:

3g of graphite powder (in the chemical industry of alatin) is dissolved in 200 ml of concentrated sulfuric acid in an ice bath to form a suspension, 3.6g of potassium nitrate is added into the suspension and stirred for 30 minutes, 18g of potassium permanganate is added into the suspension under vigorous stirring, and the system reacts for 6 hours at 35 ℃. Then, 250 ml of deionized water was added to the reaction system, and the reaction was stirred at a low temperature of 5 ℃ for 10 hours. Finally, 80ml of hydrogen peroxide and 600 ml of deionized water were added to the reaction system to terminate the reaction. And washing the obtained graphene oxide product with hydrochloric acid solution and deionized water until the overall pH value of the system reaches 7, and freeze-drying to obtain a sample.

100 mg of graphene oxide prepared as above was dissolved in 80ml of water and ultrasonically dispersed for 30 minutes to form a uniformly dispersed graphite oxide suspension, and 100 mg of pepsin and 20 ml of 1 mmol/l silver nitrate solution were added to the suspension and rapidly stirred at 37 ℃. And reacting the system in a dark room for 6 hours, centrifuging, and drying in vacuum to obtain the graphene oxide-loaded silver nanoparticles.

And adding the dried graphene oxide-loaded silver nanoparticles into water, and performing ultrasonic dispersion to obtain a suspension. Then, potassium ions on the surface of the graphene oxide are washed away by using 1mol/L hydrochloric acid, the pH of the suspension is washed to be neutral by using distilled water, and then the suspension is filtered and dried for later use.

Preparing a polyurethane microcellular foaming elastomer:

0.16g of the graphene oxide-supported silver nanoparticles prepared by the above method and 0.2g of a foaming agent were ultrasonically dispersed in 49.8g of polyester polyol (Pasf, lupraphen. H422, hydroxyl value of 56) added, and then 2.3g of ethylene glycol, 0.15g of triethylene diamine as a catalyst, 0.15g of silicone oil as a foam stabilizer AK8807, and 0.15g of dibutyl phthalate as a plasticizer were added and mixed at a high speed for later use.

To the mixture was added 30.64g of isocyanate (Pasf, CS 7319/106C-B, isocyanate value of 19.6%), stirred rapidly with a special circular stirring blade, poured into a mold, crosslinked and foamed, and then released from the mold and cured in an oven at 70 ℃ for 6 hours. Before being added into a mould, the liquid paraffin is uniformly coated on the surface of a cavity of the mould, so that the demoulding of a finished product is facilitated. The rebound rate of the prepared polyurethane microcellular foaming elastomer is 30 percent.

Comparative example 1

0.2g of foaming agent water and 49.8g of polyol (Lupraphen H422) are taken, and then 2.3g of ethylene glycol, 0.15g of triethylene diamine, 0.15g of foam stabilizer AK8807 silicone oil and 0.15g of plasticizer dibutyl phthalate are added, mixed and stirred uniformly for later use.

30.64g of isocyanate (Pasf, CS 7319/106C-B) was added to the mixture, stirred rapidly and homogeneously with a special circular stirring blade, poured into a mold for crosslinking foaming, demolded and cured in an oven at 70 ℃ for 6 hours. Before being added into a mould, the liquid paraffin is uniformly coated on the surface of a cavity of the mould, so that the demoulding of a finished product is facilitated.

The microcellular foamed polyurethane elastomers prepared in example 1 and comparative example 1 were subjected to tensile strength and elongation at break tests, and the test results are shown in fig. 1.

In addition, the polyurethane microcellular foamed elastomers prepared in example 1 and comparative example 1 were also subjected to an antibacterial property test, and the test results are shown in fig. 2. Figure 2 shows that the polyurethane microcellular foamed elastomer prepared in example 1 has good antibacterial properties (tested using staphylococcus aureus), while the sample of comparative example 1 has no antibacterial properties. The rebound resilience was 38%.

As can be seen from the test results of fig. 1 and 2, the polyurethane microcellular foamed elastomer prepared in example 1 has good mechanical properties, and the antibacterial property against staphylococcus aureus is significantly improved compared with that of a material without graphene oxide-loaded silver nanoparticles.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiment. Any modification, equivalent replacement, or improvement made without departing from the spirit and principle of the present invention shall fall within the protection scope of the present invention.

Claims (7)

1. The polyurethane composition is characterized by comprising the following components in parts by weight:

40-60 parts of polyester polyol, 30-40 parts of isocyanate, 0.1-1 part of foaming agent, 0.1-1 part of catalyst, 0.5-5 parts of chain extender, 0.1-1 part of polyurethane plasticizer, 0.1-1 part of foam stabilizer and 0.1-2 parts of graphene oxide loaded silver nanoparticles;

the foaming agent is water, dichloromethane or a mixture thereof;

the catalyst is a tertiary amine compound or an organic metal catalyst;

the organic metal catalyst is selected from stannous octoate and dibutyltin dilaurate;

the chain extender is an alcohol compound or an amine compound with a hydroxyl or amino group and a multifunctional group with low molecular weight;

the alcohol compound is selected from 1, 4-butanediol, 1, 6-hexanediol, glycerol, trimethylolpropane, diethylene glycol, triethylene glycol, neopentyl glycol, sorbitol or diethylaminoethanol;

the amine compound is selected from 3,3' -dichloro-4, 4-diamino-diphenylmethane and liquid MOCA prepared by modifying formaldehyde, ethylenediamine or N, N-dihydroxy (diisopropyl) aniline;

the polyurethane plasticizer is selected from at least one of aromatic carboxylic ester, aliphatic carboxylic ester or phosphate;

the foam stabilizer is selected from silicone oil AK8807;

the graphene oxide of the silver nano particle loaded by the graphene oxide has a single-layer sheet structure, the thickness of the graphene oxide is 1-2nm, hydroxyl and carboxyl oxygen-containing functional groups are loaded on the surface of the graphene oxide, the loaded silver particle has a nano structure, and the size of the silver particle is controlled to be 2-200 nm;

the polyester polyol is selected from Lupraphen H422;

the isocyanate is selected from Pasteur, CS 7319/106C-B;

the graphene oxide-loaded silver nanoparticles are prepared by the following method:

a) Preparation of graphene oxide

Dissolving graphite in concentrated sulfuric acid in an ice bath to form a suspension, adding potassium nitrate, stirring, and adding potassium permanganate after stirring; reacting at 20 to 45 ℃ for 1 to 12 hours; after the reaction is finished, adding water into the system, and stirring and reacting for 1 to 10 hours at the temperature of 0 to 10 ℃; finally, adding hydrogen peroxide and deionized water into the reaction system; washing the product to be neutral by using a weak acid solution;

b) Preparation of graphene oxide-loaded silver nanoparticles

Dissolving the graphene oxide prepared in the step in water, performing ultrasonic dispersion to form a suspension, then adding protease and silver nitrate solution, stirring at 30-40 ℃, reacting in a dark room, and performing centrifugal separation to obtain graphene oxide-loaded silver nanoparticles;

the protease is selected from pepsin.

2. The polyurethane composition of claim 1, wherein the tertiary amine compound is selected from the group consisting of triethylamine, N-dimethylhexadecylamine, diethylenetriamine, dimethylbenzylamine, triethylenediamine, N-methylmorpholine, N-ethylmorpholine, triethanolamine, pyridine, tetramethylbutanediamine, triethylenediamine.

3. A polyurethane composition according to claim 1 or 2, characterized in that the polyester polyol is present in an amount of 45-55 parts by weight;

30-35 parts of isocyanate;

the weight portion of the graphene oxide silver-loaded silver nanoparticles is 0.1-1.5.

4. A polyurethane microcellular foamed elastomer comprising the polyurethane composition according to any one of claims 1 to 3.

5. A method for preparing a microcellular polyurethane foam elastomer according to claim 4, which comprises the steps of:

stirring and ultrasonically dispersing polyester polyol, a foaming agent, a polyurethane plasticizer, a foam stabilizer, a catalyst, a chain extender, graphene oxide-loaded silver nanoparticles and isocyanate, and then foaming and crosslinking.

6. Use of the microcellular polyurethane foamed elastomer according to claim 4 as a polyurethane foam shoe sole.

7. Use according to claim 6, for making polyurethane soles for upper-coupled injection-moulded shoes.

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