CN116200047B - Polyurethane modified emulsified asphalt and preparation method thereof - Google Patents
Polyurethane modified emulsified asphalt and preparation method thereof Download PDFInfo
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Abstract
The application relates to the technical field of asphalt, and particularly discloses polyurethane modified emulsified asphalt and a preparation method thereof. The emulsified asphalt comprises the following raw materials: aqueous polyurethane, emulsified asphalt and water; the aqueous polyurethane comprises the following raw materials in parts by weight: 52-73 parts of diisocyanate, 22-47 parts of polyethylene glycol adipate glycol, 48-84 parts of poly epsilon-caprolactone glycol, 4-11 parts of ethylene glycol, 58-88 parts of organic solvent, 32-46 parts of epoxidized unsaturated fatty acid and 73-89 parts of polyacrylic acid; the epoxidized unsaturated fatty acid is obtained by epoxidizing unsaturated fatty acid with hydrogen peroxide solution in the presence of acetic acid. The asphalt product of the application has excellent mechanical properties in low-temperature environment.
Description
Technical Field
The application relates to the technical field of asphalt, in particular to polyurethane modified emulsified asphalt and a preparation method thereof.
Background
Asphalt has been attracting attention as one of the most basic materials for road construction. The basic emulsified asphalt has the defects of poor mechanical property, insufficient high-low temperature performance and the like, so that the problems of grooves, cracks, rutting and the like appear in the early stage of public and lewis, and the polymer modified emulsified asphalt is adopted.
Among the polymers for modifying emulsified asphalt, polyurethane has been receiving much attention due to its designable molecular structure and excellent low temperature resistance and toughness. In the polyurethane synthesis process, active carboxyl, urea, ester and the like can be introduced to enable polyurethane to have different effects, so that asphalt is modified and related properties of the asphalt are excellent. Wherein, aiming at the defect of insufficient low-temperature performance existing in the existing polyurethane modified asphalt, the scheme in the prior art when preparing the modified asphalt is as follows: step one, reacting polytetrahydrofuran-650 (PTMEG-650) and isophorone diisocyanate (IPDI) for 3 hours under nitrogen at 90 ℃ so that the-NCO group of the IPDI reacts with PTMEG-650; cooling to 80 ℃, adding 2, 2-dihydroxymethylpropanoic acid (DMPA), maintaining the temperature at 80 ℃ and continuously reacting for 3 hours; then polyethylene glycol-2000 (PEG-2000) was added and reacted at 80℃for 3 hours to obtain aqueous polyurethane. Step two, mixing the aqueous polyurethane with water and emulsified asphalt to obtain aqueous polyurethane emulsified asphalt; and step three, mixing the epoxy resin, the curing agent and the aqueous polyurethane emulsified asphalt to obtain the epoxy resin modified aqueous polyurethane emulsified asphalt.
For the related technology, when the epoxy resin modified waterborne polyurethane emulsified asphalt is subjected to low-temperature performance detection, the freeze thawing splitting strength ratio is only 57.5% at most, and the splitting tensile strength at low temperature is still to be improved.
Disclosure of Invention
In order to improve the splitting tensile strength of polyurethane modified emulsified asphalt at low temperature, the application provides polyurethane modified emulsified asphalt and a preparation method thereof.
In a first aspect, the present application provides a polyurethane modified emulsified asphalt, which adopts the following technical scheme:
a polyurethane modified emulsified asphalt comprises the following raw materials:
the asphalt comprises water-based polyurethane, emulsified asphalt and water, wherein the water-based polyurethane accounts for 10-15% of the weight of the emulsified asphalt, and the water accounts for 10-18 times of the weight of the water-based polyurethane;
taking the weight of the aqueous polyurethane as a reference, the aqueous polyurethane comprises the following raw materials in parts by weight:
52-73 parts of diisocyanate, 22-47 parts of polyethylene glycol adipate glycol, 48-84 parts of poly epsilon-caprolactone glycol, 4-11 parts of ethylene glycol, 58-88 parts of organic solvent, 32-46 parts of epoxidized unsaturated fatty acid and 73-89 parts of polyacrylic acid;
the epoxidized unsaturated fatty acid is obtained by epoxidizing unsaturated fatty acid with hydrogen peroxide solution in the presence of acetic acid.
The waterborne polyurethane is obtained by modifying polyurethane through epoxidized unsaturated fatty acid and polyacrylic acid. Polyacrylic acid has a certain amount of active-COOH, while-c=c-on unsaturated fatty acids will show epoxy groups after epoxidation, and free-COOH is also present on the epoxidized unsaturated fatty acids themselves, the-COOH on polyacrylic acid, the epoxy groups on epoxidized unsaturated fatty acids and-COOH interact with-NCO groups on polyurethane to improve its structural stability. The epoxidized unsaturated fatty acid is integrally in a linear structure, and molecules of the linear structure are inserted into the polyacrylic acid and polyurethane molecules and connected with the polyacrylic acid and polyurethane molecules; in addition, the epoxy groups on the epoxidized unsaturated fatty acid also enable the epoxidized unsaturated fatty acid molecules to form an interpenetrating structure, so that the three components finally form a stable three-dimensional interpenetrating network structure. When the waterborne polyurethane is used for modifying emulsified asphalt, lipophilic groups on the waterborne polyurethane act on asphalt and enter the inside of the asphalt, so that the combination stability of the lipophilic groups and the asphalt is improved, and the mechanical property of the asphalt is improved. The method comprises the following steps: the introduced polyacrylic acid can obviously improve the hydrophilicity of polyurethane, so as to improve the hydrophilicity of asphalt, thereby improving the stability of the polyurethane modified emulsified asphalt and the low-temperature mechanical property of the polyurethane modified emulsified asphalt. In addition, due to the introduction of-COOH, the-OH in the aqueous polyurethane and the emulsified asphalt provided by the application is reacted, so that the bonding stability of the aqueous polyurethane and the emulsified asphalt is further improved. In conclusion, the low-temperature mechanical properties of the emulsified asphalt which finally shows polyurethane modification are obviously improved.
Optionally, the preparation method of the epoxidized unsaturated fatty acid comprises the following steps: mixing and stirring the unsaturated fatty acid, the hydrogen peroxide solution and acetic acid at normal temperature for 30-60min to obtain the aqueous solution; the mol ratio of the unsaturated fatty acid to the hydrogen peroxide is 1 (2.5-3.5), the mol ratio of the acetic acid to the hydrogen peroxide is 1 (1.2-1.5), and the mass percentage of the hydrogen peroxide in the hydrogen peroxide solution is 45-55wt%.
The epoxidized unsaturated fatty acid should be properly epoxidized, and it is noted here that the transitional epoxidation of the unsaturated fatty acid will cause excessive impurities and even the occurrence of carbon chain breakage of the unsaturated fatty acid at the site of formation of the epoxy group, so by adopting the above-mentioned technical scheme, the properly epoxidized unsaturated fatty acid is obtained so as to exert excellent effects of penetrating and connecting polyurethane, polyacrylic acid at a later stage.
Optionally, the unsaturated fatty acid comprises 65-85% of monounsaturated fatty acid and the balance polyunsaturated fatty acid by mass percent.
After the polyunsaturated fatty acid is epoxidized, epoxy groups on one polyunsaturated fatty acid are more, so that not only the epoxidized polyunsaturated fatty acid molecules are inserted into the polyacrylic acid molecules and the polyurethane molecules, but also the epoxidized polyunsaturated fatty acid molecules are mutually inserted and crosslinked, and the same epoxidized polyunsaturated fatty acid molecules are curled and inserted. Therefore, after the unsaturated fatty acid is further arranged as the mixture of the monounsaturated fatty acid and the polyunsaturated fatty acid, the interpenetrating structure can be further complicated and fine, and the strength of the aqueous polyurethane is further improved, so that the low-temperature mechanical property of the polyurethane modified emulsified asphalt is improved. However, polyunsaturated fatty acids are not preferred in excess, which would otherwise affect the interaction of-COOH with-NCO on emulsified bitumen. Therefore, the regulation and control of the low-temperature mechanical properties of the final polyurethane modified emulsified asphalt are realized by adjusting the relative dosage of the monounsaturated fatty acid and the polyunsaturated fatty acid; the preparation of the epoxidized unsaturated fatty acid from the monounsaturated fatty acid and the polyunsaturated fatty acid in the proportion can obtain the polyurethane modified emulsified asphalt with excellent low-temperature mechanical properties.
Optionally, the monounsaturated fatty acid is selected from one or two of palmitoleic acid and oleic acid; the polyunsaturated fatty acid is selected from one or more of linolenic acid, linoleic acid and arachidonic acid.
Optionally, the preparation method of the aqueous polyurethane comprises the following steps:
s1, mixing polyethylene glycol adipate glycol and an organic solvent to obtain a first mixed solution;
heating poly epsilon-caprolactone glycol to be molten to obtain a second mixed solution;
mixing the first mixed solution, the second mixed solution and diisocyanate, and reacting at 70-80 ℃ to obtain polyurethane prepolymer;
s2, cooling the polyurethane prepolymer to 40-50 ℃, adding ethylene glycol, epoxidized unsaturated fatty acid and polyacrylic acid, reacting at 70-80 ℃ for 3-5h, and cooling to obtain the waterborne polyurethane.
By adopting the technical scheme, the aqueous polyurethane with excellent performance can be obtained at proper reaction temperature and reaction time, and the obtained asphalt product has excellent low-temperature mechanical performance after the aqueous polyurethane is used for modifying emulsified asphalt.
Optionally, the reaction time in the step S1 is 30-60min.
Optionally, the organic solvent is any one of acetone and toluene.
Alternatively, the diisocyanate is selected from any one or more of toluene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate and lysine diisocyanate.
In a second aspect, the application provides a preparation method of the polyurethane modified emulsified asphalt, which adopts the following technical scheme:
the preparation method of the polyurethane modified emulsified asphalt comprises the following steps:
step one, mixing the aqueous polyurethane and the water according to a proportion and uniformly stirring to obtain an aqueous polyurethane solution;
and step two, mixing the emulsified asphalt in the aqueous polyurethane solution and uniformly stirring to obtain the polyurethane modified emulsified asphalt.
Optionally, in the second step, the stirring speed is 6000-8500rpm.
In summary, the application has the following beneficial effects:
1. the polyurethane is modified by the epoxidation unsaturated fatty acid and the polyacrylic acid together so as to obtain the waterborne polyurethane with improved hydrophilicity and stability; meanwhile, due to the introduction of-COOH and epoxy groups, the combination of the waterborne polyurethane and the emulsified asphalt is stable, and finally, the low-temperature mechanical property and the Marshall stability of the polyurethane modified emulsified asphalt are improved.
2. The preparation raw materials of the epoxidized unsaturated fatty acid are further selected to be a mixture of monounsaturated fatty acid and polyunsaturated fatty acid, and the low-temperature mechanical property and Marshall stability of the polyurethane modified emulsified asphalt are adjusted through the adjustment of the proportion of the monounsaturated fatty acid and the polyunsaturated fatty acid; finally, when the two are mixed in a specific proportion (65-85% of monounsaturated fatty acid and the balance of polyunsaturated fatty acid), the polyurethane modified emulsified asphalt has excellent low-temperature mechanical property and Marshall stability.
Detailed Description
The present application will be described in further detail with reference to examples.
In the present application, TDI refers to a diisocyanate selected from toluene diisocyanate, MDI refers to diphenylmethane diisocyanate, HMDI refers to dicyclohexylmethane diisocyanate, HDI refers to hexamethylene diisocyanate, and LDI refers to lysine diisocyanate. The raw materials related to the application are commonly and commercially available unless otherwise specified.
Preparation of epoxidized unsaturated fatty acids
Preparation example 1
The preparation raw materials of the epoxidized unsaturated fatty acid are as follows:
unsaturated fatty acid: is obtained by mixing palmitoleic acid (also called 9-hexadecenoic acid) and oleic acid in a mass ratio of 1:1; the mass percentage of the hydrogen peroxide is 45wt% of hydrogen peroxide solution and acetic acid. Wherein, the mol ratio of unsaturated fatty acid to hydrogen peroxide is 1:2.5, and the mol ratio of acetic acid to hydrogen peroxide is 1:1.2.
The preparation method of the epoxidized unsaturated fatty acid comprises the following steps: mixing and stirring unsaturated fatty acid, hydrogen peroxide solution and acetic acid for 30min at normal temperature to obtain crude epoxidized unsaturated fatty acid, and then washing the crude epoxidized unsaturated fatty acid with water and removing water to obtain the epoxidized unsaturated fatty acid.
Preparation example 2
The preparation raw materials of the epoxidized unsaturated fatty acid are as follows:
unsaturated fatty acid: is prepared by mixing palmitoleic acid, oleic acid, linolenic acid and linoleic acid according to the mass ratio of 1:1:1:1; the mass percentage of the hydrogen peroxide is 50wt% of hydrogen peroxide solution and acetic acid. Wherein, the mol ratio of unsaturated fatty acid to hydrogen peroxide is 1:3, and the mol ratio of acetic acid to hydrogen peroxide is 1:1.4.
The preparation method of the epoxidized unsaturated fatty acid comprises the following steps: mixing and stirring unsaturated fatty acid, hydrogen peroxide solution and acetic acid for 50min at normal temperature to obtain crude epoxidized unsaturated fatty acid, and then washing the crude epoxidized unsaturated fatty acid with water and removing water to obtain the epoxidized unsaturated fatty acid.
Preparation example 3
The preparation raw materials of the epoxidized unsaturated fatty acid are as follows:
unsaturated fatty acid: is obtained by mixing linolenic acid, arachidonic acid and linoleic acid in a mass ratio of 1:1:1; the mass percentage of the hydrogen peroxide is 55wt% of hydrogen peroxide solution and acetic acid. Wherein, the mol ratio of unsaturated fatty acid to hydrogen peroxide is 1:3.5, and the mol ratio of acetic acid to hydrogen peroxide is 1:1.5.
The preparation method of the epoxidized unsaturated fatty acid comprises the following steps: mixing and stirring unsaturated fatty acid, hydrogen peroxide solution and acetic acid at normal temperature for 60min to obtain crude epoxidized unsaturated fatty acid, and then washing the crude epoxidized unsaturated fatty acid with water and removing water to obtain the epoxidized unsaturated fatty acid.
Preparation example 4
The difference between the preparation example and the preparation example 2 is that the proportion of unsaturated fatty acid is different, specifically: the unsaturated fatty acid is composed of 65wt% of monounsaturated fatty acid and 35wt% of polyunsaturated fatty acid, wherein the monounsaturated fatty acid is obtained by mixing palmitoleic acid and oleic acid in a mass ratio of 1:1, and the polyunsaturated fatty acid is obtained by mixing linolenic acid and linoleic acid in a mass ratio of 1:1. The procedure of preparation 2 is otherwise followed.
Preparation example 5
The difference between the preparation example and the preparation example 2 is that the proportion of unsaturated fatty acid is different, specifically: the unsaturated fatty acid is composed of 75wt% of monounsaturated fatty acid and 25wt% of polyunsaturated fatty acid, and the specific composition of monounsaturated fatty acid and polyunsaturated fatty acid is the same as in preparation example 4. The procedure of preparation 2 is otherwise followed.
Preparation example 6
The difference between the preparation example and the preparation example 2 is that the proportion of unsaturated fatty acid is different, specifically: the unsaturated fatty acid is composed of 85wt% of monounsaturated fatty acid and 15wt% of polyunsaturated fatty acid, and the specific composition of monounsaturated fatty acid and polyunsaturated fatty acid is the same as in preparation example 4. The procedure of preparation 2 is otherwise followed.
Preparation example 7
The difference between the preparation example and the preparation example 2 is that the proportion of unsaturated fatty acid is different, specifically: the unsaturated fatty acid is composed of 90wt% of monounsaturated fatty acid and 10wt% of polyunsaturated fatty acid, and the specific composition of monounsaturated fatty acid and polyunsaturated fatty acid is the same as in preparation example 4. The procedure of preparation 2 is otherwise followed.
Preparation example 8
The preparation example and the preparation example 2 are different in components and proportions of unsaturated fatty acid, and specifically comprise the following steps: the unsaturated fatty acid contained only monounsaturated fatty acid, and the specific composition of monounsaturated fatty acid was the same as that of preparation example 4. The procedure of preparation 2 is otherwise followed.
Preparation example 9
The preparation example and the preparation example 2 are different in components and proportions of unsaturated fatty acid, and specifically comprise the following steps: the unsaturated fatty acid only contains polyunsaturated fatty acids, and the specific composition of the polyunsaturated fatty acid is the same as in preparation example 4. The procedure of preparation 2 is otherwise followed.
Preparation example of aqueous polyurethane
Preparation example 1
The preparation raw materials of the aqueous polyurethane are as follows:
52g of toluene diisocyanate, 22g of polyethylene glycol adipate glycol, 48g of poly epsilon-caprolactone glycol, 4g of ethylene glycol, 58g of toluene, 32g of epoxidized unsaturated fatty acid and 73g of polyacrylic acid; wherein the CAS number of the polyethylene glycol adipate glycol is 24938-37-2, the CAS number of the poly epsilon-caprolactone glycol is 36890-68-3, the CAS number of the polyacrylic acid is 9003-01-4, and the epoxidized unsaturated fatty acid is prepared by epoxidizing the unsaturated fatty acid preparation example 1.
The preparation method of the aqueous polyurethane comprises the following steps:
s1, mixing the polyethylene glycol adipate glycol with toluene to obtain a first mixed solution;
heating the poly epsilon-caprolactone diol with the amount to be molten to obtain a second mixed solution;
mixing all the first mixed solution, the second mixed solution and the toluene diisocyanate with the above amount, and reacting at 70 ℃ for 60min to obtain polyurethane prepolymer;
s2, cooling the polyurethane prepolymer to 40 ℃, adding the above amount of ethylene glycol, epoxidized unsaturated fatty acid and polyacrylic acid, reacting for 5 hours at 70 ℃, cooling, filtering, and dehydrating and drying the filtrate to obtain the water-based polyurethane.
Preparation example 2
The preparation raw materials of the aqueous polyurethane are as follows:
65g of diphenylmethane diisocyanate, 34g of polyethylene glycol adipate glycol, 63g of poly epsilon-caprolactone glycol, 8g of ethylene glycol, 62g of toluene, 38g of epoxidized unsaturated fatty acid and 79g of polyacrylic acid; wherein polyethylene glycol adipate diol, poly epsilon-caprolactone diol and polyacrylic acid are prepared in the same way as in preparation example 1, and the epoxidized unsaturated fatty acid is prepared in preparation example 2.
The preparation method of the aqueous polyurethane comprises the following steps:
s1, preparing a first mixed solution and a second mixed solution, wherein the steps are the same as those of preparation example 1;
mixing all the first mixed solution, the second mixed solution and the diphenylmethane diisocyanate with the above amount, and reacting for 45min at 75 ℃ to obtain polyurethane prepolymer;
s2, cooling the polyurethane prepolymer to 45 ℃, adding the ethylene glycol, the epoxidized unsaturated fatty acid and the polyacrylic acid in the amounts, reacting for 4 hours at 75 ℃, cooling, filtering, and dehydrating and drying the filtrate to obtain the water-based polyurethane.
Preparation example 3
The preparation raw materials of the aqueous polyurethane are as follows:
73g of dicyclohexylmethane diisocyanate, 47g of polyethylene glycol adipate glycol, 84g of poly epsilon-caprolactone glycol, 11g of ethylene glycol, 88g of toluene, 46g of epoxidized unsaturated fatty acid and 89g of polyacrylic acid; wherein polyethylene glycol adipate diol, poly epsilon-caprolactone diol and polyacrylic acid are prepared in the same way as in preparation example 1, and the epoxidized unsaturated fatty acid is prepared in preparation example 3.
The preparation method of the aqueous polyurethane comprises the following steps:
s1, preparing a first mixed solution and a second mixed solution, wherein the steps are the same as those of preparation example 1;
mixing all the first mixed solution, the second mixed solution and the diphenylmethane diisocyanate with the above amount, and reacting for 30min at 80 ℃ to obtain polyurethane prepolymer;
s2, cooling the polyurethane prepolymer to 50 ℃, adding the ethylene glycol, the epoxidized unsaturated fatty acid and the polyacrylic acid in the amounts, reacting for 3 hours at 80 ℃, cooling, filtering, and dehydrating and drying the filtrate to obtain the water-based polyurethane.
Preparation examples 4 to 9
Preparation examples 4 to 9 differ from preparation example 2 in that epoxidized unsaturated fatty acids were prepared from different preparation examples of epoxidized unsaturated fatty acids, respectively, and the other was the same as preparation example 2. The specific conditions of the epoxidized unsaturated fatty acids selected for different aqueous polyurethanes are shown in Table 1.
TABLE 1 specific case of epoxidized unsaturated fatty acids selected for different waterborne polyurethanes
Preparation example 10
This preparation example differs from preparation example 5 in that the polyacrylic acid was replaced with an equal weight of epoxidized unsaturated fatty acid in the preparation of the aqueous polyurethane, and the same procedure as in preparation example 5 was followed. The preparation raw materials of the aqueous polyurethane specifically comprise:
65g of diphenylmethane diisocyanate, 34g of polyethylene glycol adipate glycol, 63g of poly epsilon-caprolactone glycol, 8g of ethylene glycol, 62g of toluene and 117g of epoxidized unsaturated fatty acid.
PREPARATION EXAMPLE 11
This preparation example differs from preparation example 5 in that the epoxidized unsaturated fatty acid is replaced with an equal weight of polyacrylic acid in the preparation of the aqueous polyurethane, and the same procedure as in preparation example 5 is followed. The preparation raw materials of the aqueous polyurethane specifically comprise:
65g of diphenylmethane diisocyanate, 34g of polyethylene glycol adipate glycol, 63g of poly epsilon-caprolactone glycol, 8g of ethylene glycol, 62g of toluene and 117g of polyacrylic acid.
Preparation example 12
The difference between this preparation example and preparation example 5 is that the amount of the epoxidized unsaturated fatty acid added in the preparation of the aqueous polyurethane was different, and the same procedure as in preparation example 5 was followed. The preparation raw materials of the aqueous polyurethane specifically comprise:
65g of diphenylmethane diisocyanate, 34g of polyethylene glycol adipate glycol, 63g of poly epsilon-caprolactone glycol, 8g of ethylene glycol, 62g of toluene, 28g of epoxidized unsaturated fatty acid and 79g of polyacrylic acid.
Preparation example 13
The difference between this preparation example and preparation example 5 is that the amount of the epoxidized unsaturated fatty acid added in the preparation of the aqueous polyurethane was different, and the same procedure as in preparation example 5 was followed. The preparation raw materials of the aqueous polyurethane specifically comprise:
65g of diphenylmethane diisocyanate, 34g of polyethylene glycol adipate glycol, 63g of poly epsilon-caprolactone glycol, 8g of ethylene glycol, 62g of toluene, 50g of epoxidized unsaturated fatty acid and 79g of polyacrylic acid.
PREPARATION EXAMPLE 14
The difference between this preparation example and preparation example 5 is that the amount of polyacrylic acid added when preparing the aqueous polyurethane was different, and the same procedure as in preparation example 5 was followed. The preparation raw materials of the aqueous polyurethane specifically comprise:
65g of diphenylmethane diisocyanate, 34g of polyethylene glycol adipate glycol, 63g of poly epsilon-caprolactone glycol, 8g of ethylene glycol, 62g of toluene, 38g of epoxidized unsaturated fatty acid and 68g of polyacrylic acid.
Preparation example 15
The difference between this preparation example and preparation example 5 is that the amount of polyacrylic acid added when preparing the aqueous polyurethane was different, and the same procedure as in preparation example 5 was followed. The preparation raw materials of the aqueous polyurethane specifically comprise:
65g of diphenylmethane diisocyanate, 34g of polyethylene glycol adipate glycol, 63g of poly epsilon-caprolactone glycol, 8g of ethylene glycol, 62g of toluene, 38g of epoxidized unsaturated fatty acid and 94g of polyacrylic acid.
The raw materials and components of the aqueous polyurethane preparation examples 10-15 are shown in Table 2.
TABLE 2 raw materials and Components of aqueous polyurethane preparation examples 10-15
PREPARATION EXAMPLE 16
The difference between this preparation example and preparation example 5 is that when preparing the aqueous polyurethane, the epoxidized unsaturated fatty acid is replaced with an equal weight of unsaturated fatty acid, the unsaturated fatty acid is composed of 75% by weight of monounsaturated fatty acid and 25% by weight of polyunsaturated fatty acid, the monounsaturated fatty acid is obtained by mixing palmitoleic acid and oleic acid in a mass ratio of 1:1, and the polyunsaturated fatty acid is obtained by mixing linolenic acid and linoleic acid in a mass ratio of 1:1, otherwise, the same as preparation example 5.
The preparation raw materials of the aqueous polyurethane specifically comprise:
65g of diphenylmethane diisocyanate, 34g of polyethylene glycol adipate glycol, 63g of poly epsilon-caprolactone glycol, 8g of ethylene glycol, 62g of toluene, 38g of unsaturated fatty acid and 79g of polyacrylic acid.
Examples
Example 1
The polyurethane modified emulsified asphalt comprises the following components in percentage by weight: 200g of emulsified asphalt, 10wt% of aqueous polyurethane of the emulsified asphalt and 10 times of water of the aqueous polyurethane. Wherein, the aqueous polyurethane is prepared by aqueous polyurethane preparation example 1; emulsified asphalt was purchased from engineering materials limited of taan city.
The preparation method of the polyurethane modified emulsified asphalt comprises the following steps:
step one, mixing water-based polyurethane and water according to a proportion, and stirring for 30min to obtain a water-based polyurethane solution;
and step two, mixing the emulsified asphalt in the aqueous polyurethane solution and uniformly stirring at the rotating speed of 6000rpm to obtain the polyurethane modified emulsified asphalt.
Example 2
The polyurethane modified emulsified asphalt comprises the following components in percentage by weight: 200g of emulsified asphalt, 12wt% of aqueous polyurethane of which the weight is 15 times that of water. Wherein, the aqueous polyurethane is prepared by aqueous polyurethane preparation example 2; emulsified asphalt was as in example 1.
The preparation method of the polyurethane modified emulsified asphalt comprises the following steps:
step one, mixing water-based polyurethane and water according to a proportion, and stirring for 35min to obtain a water-based polyurethane solution;
and step two, mixing the emulsified asphalt in the aqueous polyurethane solution and uniformly stirring at the rotating speed of 8000rpm to obtain the polyurethane modified emulsified asphalt.
Example 3
The polyurethane modified emulsified asphalt comprises the following components in percentage by weight: 200g of emulsified asphalt, 15wt% of aqueous polyurethane of the emulsified asphalt and 18 times of water of the aqueous polyurethane. Wherein, the aqueous polyurethane is prepared by aqueous polyurethane preparation example 3; emulsified asphalt was as in example 1.
The preparation method of the polyurethane modified emulsified asphalt comprises the following steps:
step one, mixing water-based polyurethane and water according to a proportion, and stirring for 40min to obtain a water-based polyurethane solution;
and step two, mixing the emulsified asphalt in the aqueous polyurethane solution and uniformly stirring at the rotating speed of 8500rpm to obtain the polyurethane modified emulsified asphalt.
Examples 4 to 9
Examples 4-9 differ from example 2 in that the aqueous polyurethanes were prepared from different aqueous polyurethane preparations, see in particular Table 3.
TABLE 3 selection of aqueous polyurethanes in different examples
Comparative example
Comparative examples 1 to 6
Comparative examples 1 to 6 differ from example 2 in that the aqueous polyurethanes were prepared from different aqueous polyurethane preparations, see in particular table 4.
Table 4 selection of waterborne polyurethanes in different comparative examples
Performance test the relevant detection of freeze thawing split tensile strength of the obtained asphalt product was carried out with reference to asphalt mixture freeze thawing split test T0729-2000, marshall stability test was carried out with reference to highway engineering asphalt and asphalt mixture test procedure (JTg/E20-2011), and specific results are shown in table 5.
Table 5 freeze-thaw split tensile strength and marshall stability of bitumen products in various embodiments
As can be seen from the data in examples 1-9 of Table 5, the bitumen product prepared according to the present application (i.e. the polyurethane modified emulsified bitumen prepared according to the present application) has an excellent low Wen Pilie tensile strength. Comparing any of examples 2, 4-7 with any of examples 8-9, it was found that when the epoxidized unsaturated fatty acid was prepared using a mixture of polyunsaturated fatty acid and monounsaturated fatty acid as the starting material, the prepared asphalt product had more excellent freeze-thaw cleavage tensile strength and marshall stability than either polyunsaturated fatty acid alone or monounsaturated fatty acid alone.
Furthermore, the results of examples 2, 4-7 show that: when the preparation raw materials of the epoxidized unsaturated fatty acid are the mixture of polyunsaturated fatty acid and monounsaturated fatty acid, and the specific proportion of the monounsaturated fatty acid and the rest polyunsaturated fatty acid is 65-85%, the freeze thawing split tensile strength and Marshall stability of the finally obtained asphalt product are improved. This result demonstrates that the control of freeze-thaw cleavage tensile strength and marshall stability of bitumen products can be achieved by controlling the ratio of polyunsaturated fatty acids to monounsaturated fatty acids. This is probably because, relatively speaking, the epoxidized unsaturated fatty acid molecules exhibit a linear structure or a simple cyclic curved structure, whereas the polyurethane and polyacrylic acid exhibit a three-dimensional network structure as polymers, and the epoxidized unsaturated fatty acid molecules are able to interpenetrate and act as "anchors" for the polyurethane and polyacrylic acid linkages, causing the two polymers to further crosslink on a stable linkage basis. The number and positions of epoxy groups on the epoxidized polyunsaturated fatty acid and the monounsaturated fatty acid are different, which affects the interpenetrating crosslinking among the epoxidized unsaturated fatty acid molecules, the interpenetrating crosslinking among the epoxidized unsaturated fatty acid molecules and the polyurethane molecules and the interpenetrating crosslinking among the epoxidized unsaturated fatty acid molecules and the polyacrylic acid molecules; the different results of the action further affect the interaction between the aqueous polyurethane and the emulsified asphalt, ultimately leading to a difference in the properties of the asphalt product.
As can be seen from the data of comparative examples 5 and comparative examples 1 to 2, it is indispensable to replace the epoxidized unsaturated fatty acid with polyacrylic acid in the preparation of aqueous polyurethane. It is possible that the epoxidized unsaturated fatty acid acts as an "anchor" for the polyurethane and polyacrylic acid linkage, which decreases in stability in the absence of the epoxidized unsaturated fatty acid; in addition, the reduction of carboxyl groups also weakens the interaction between the aqueous polyurethane and the emulsified asphalt, ultimately leading to a decrease in the performance of the asphalt product. In addition, as shown in comparative examples 5 and 7, when unsaturated fats are selected as raw materials in the preparation of the aqueous polyurethane, and when the aqueous polyurethane is used for the preparation of an asphalt product instead of epoxidized unsaturated fatty acids, the freeze-thawing split tensile strength and Marshall stability of the obtained asphalt product are significantly reduced. This result is a significant indication of the importance of the epoxidation treatment of unsaturated fatty acids.
The data of example 5 and comparative examples 3-6 show that the epoxidized unsaturated fatty acid is recommended to be in the range of 32-46 parts when preparing the aqueous polyurethane, the polyacrylic acid is recommended to be in the range of 73-89 parts, otherwise, the prepared emulsified asphalt still has difficulty in having excellent freeze thawing split tensile strength and Marshall stability. This is probably because the amount of epoxidized unsaturated fatty acid used is too small (comparative example 3), and the connection stability of polyurethane and polyacrylic acid is lowered, resulting in a decrease in the mechanical properties of asphalt product and the melt fracture tensile strength. When the epoxidized unsaturated fatty acid is used in an excessive amount (comparative example 4), the polymer content is relatively small, and the strength of the linear molecule is lower than that of the polymer state; in addition, polyurethane molecules acting with emulsified asphalt are reduced, resulting in reduced binding stability; therefore, epoxidized unsaturated fatty acids are recommended to be in the range of 32-46 parts. If the amount of polyacrylic acid used is too small (comparative example 5), in the aqueous polyurethane, the polyurethane mainly interacts with the epoxidized unsaturated fatty acid, so that further crosslinking among different polymer molecules is difficult to realize, the intermolecular bonding in the aqueous polyurethane is unstable, and in addition, the reduction of carboxyl groups can reduce the interaction between the aqueous polyurethane and emulsified asphalt; if the amount of polyacrylic acid used is too large (comparative example 6), the binding stability between polyurethane and polyacrylic acid in the aqueous polyurethane is lowered, resulting in unstable intermolecular binding of the aqueous polyurethane.
The present embodiment is only for explanation of the present application and is not to be construed as limiting the present application, and modifications to the present embodiment, which may not creatively contribute to the present application as required by those skilled in the art after reading the present specification, are all protected by patent laws within the scope of claims of the present application.
Claims (9)
1. The polyurethane modified emulsified asphalt is characterized by comprising the following raw materials:
the asphalt comprises water-based polyurethane, emulsified asphalt and water, wherein the water-based polyurethane accounts for 10-15% of the weight of the emulsified asphalt, and the water accounts for 10-18 times of the weight of the water-based polyurethane;
taking the weight of the aqueous polyurethane as a reference, the aqueous polyurethane comprises the following raw materials in parts by weight:
52-73 parts of diisocyanate, 22-47 parts of polyethylene glycol adipate glycol, 48-84 parts of poly epsilon-caprolactone glycol, 4-11 parts of ethylene glycol, 58-88 parts of organic solvent, 32-46 parts of epoxidized unsaturated fatty acid and 73-89 parts of polyacrylic acid;
the epoxidized unsaturated fatty acid is obtained by epoxidizing unsaturated fatty acid with hydrogen peroxide solution in the presence of acetic acid;
the preparation method of the epoxidized unsaturated fatty acid comprises the following steps: mixing and stirring the unsaturated fatty acid, the hydrogen peroxide solution and acetic acid at normal temperature for 30-60min to obtain the aqueous solution; the mol ratio of the unsaturated fatty acid to the hydrogen peroxide is 1 (2.5-3.5), the mol ratio of the acetic acid to the hydrogen peroxide is 1 (1.2-1.5), and the mass percentage of the hydrogen peroxide in the hydrogen peroxide solution is 45-55wt%.
2. A polyurethane modified emulsified asphalt as set forth in claim 1, wherein the unsaturated fatty acids include 65-85% by mass of monounsaturated fatty acids and the balance polyunsaturated fatty acids.
3. A polyurethane modified emulsified asphalt as set forth in claim 2, wherein the monounsaturated fatty acid is selected from one or both of palmitoleic acid and oleic acid; the polyunsaturated fatty acid is selected from one or more of linolenic acid, linoleic acid and arachidonic acid.
4. The polyurethane-modified emulsified asphalt as set forth in claim 1, wherein the preparation method of the aqueous polyurethane comprises the steps of:
s1, mixing polyethylene glycol adipate glycol and an organic solvent to obtain a first mixed solution;
heating poly epsilon-caprolactone glycol to be molten to obtain a second mixed solution;
mixing the first mixed solution, the second mixed solution and diisocyanate, and reacting at 70-80 ℃ to obtain polyurethane prepolymer;
s2, cooling the polyurethane prepolymer to 40-50 ℃, adding ethylene glycol, epoxidized unsaturated fatty acid and polyacrylic acid, reacting at 70-80 ℃ for 3-5h, and cooling to obtain the waterborne polyurethane.
5. A polyurethane-modified emulsified asphalt as set forth in claim 4, wherein the reaction time in step S1 is 30 to 60 minutes.
6. The polyurethane-modified emulsified asphalt as set forth in claim 4, wherein the organic solvent is any one of acetone and toluene.
7. A polyurethane modified emulsified asphalt as set forth in claim 1, wherein the diisocyanate is selected from any one or more of toluene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate and lysine diisocyanate.
8. A process for preparing a polyurethane-modified emulsified asphalt as set forth in any one of claims 1 to 7, wherein the process comprises the steps of:
step one, mixing the aqueous polyurethane and the water according to a proportion and uniformly stirring to obtain an aqueous polyurethane solution;
and step two, mixing the emulsified asphalt in the aqueous polyurethane solution and uniformly stirring to obtain the polyurethane modified emulsified asphalt.
9. The method for producing a polyurethane-modified emulsified asphalt as set forth in claim 8, wherein the stirring speed in the second step is 6000 to 8500rpm.
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