Polybutadiene liquid rubber as well as preparation method and application thereof

Abstract

The invention provides polybutadiene liquid rubber as well as a preparation method and application thereof. The polybutadiene liquid rubber is of a double-end structure and has a long hydrophobic group, and the molecular formula of the polybutadiene liquid rubber is CaHbCl2O6 (C4H6) n; the preparation method comprises the following steps: carrying out ester exchange reaction on 2-(4-chloro-2-methylphenoxy) propionic acid and double-end hydroxyl polybutadiene to obtain double-end (R)-2-(4-chloro-2-methylphenoxy) propionate modified polybutadiene liquid rubber; or carrying out ester exchange reaction on the clofibric acid and the double-end hydroxyl polybutadiene to obtain double-end (R)-2-(4-chlorophenoxy)-2-methyl propionate modified polybutadiene liquid rubber; the polybutadiene liquid rubber is of a double-end structure and has a long hydrophobic group, so that the product has high insoluble water property, and the risk of water resource environmental pollution caused by migration of the root inhibitor is greatly reduced.

Description

Technical Field

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

[0002] In recent years, with the country's high attention to building energy conservation, green roof systems have been widely promoted and applied. The effective life of the green roof system depends to a certain extent on the root penetration resistance of the root penetration-resistant waterproof material. There are two root barrier principles for puncture-resistant waterproof membranes: one is to use the material properties of the waterproof membrane itself and the firmness of the joints to achieve the purpose of root barrier; the other is to add a root barrier agent with a smaller molecular weight to the waterproof membrane, such as a small molecule single-ended (R)-2-(4-chloro-2-methylphenoxy) propionate compound, and use the root barrier effect of the root barrier agent's (R)-2-(4-chloro-2-methylphenoxy) structure to inhibit plant roots from penetrating the waterproof layer. However, the existing solutions have the following problems: the root barrier agent has a small molecular weight, the hydrophobicity of one section is limited, there is a migration risk, and it has an impact on the water resources environment. In addition, root inhibitors may fail to prevent the waterproof layer (such as waterproof membrane or liquid waterproof coating) from root blocking due to migration problems, such as the mainstream (R)-2-(4-chloro-2-methylphenoxy) octyl propionate, (R)-2-(4-chloro-2-methylphenoxy) butyl propionate, (R)-2-(4-chloro-2-methylphenoxy) polyoxyethylene propionate and other similar structural products. Summary of the Invention

[0003] In order to overcome the shortcomings of the prior art, the first object of the present invention is to provide a polybutadiene liquid rubber, which has a double-ended structure and a long hydrophobic group, so that the product has high water insolubility, greatly reducing the problem of migration when used as a root inhibitor and thus causing pollution to water resources.

[0004] The second object of the present invention is to provide a method for preparing the above-mentioned polybutadiene liquid rubber; the preparation method is simple, efficient and stable and can be used for industrial production.

[0005] The third object of the present invention is to provide an application of the above-mentioned polybutadiene liquid rubber, which can be used to prepare a root inhibitor, which not only has the effect of root inhibition, but also has the function of enhancing the toughness, elasticity and low-temperature resistance of the system.

[0006] The first object of the present invention can be achieved by adopting the following technical solution: the polybutadiene liquid rubber has a double-ended structure and a long hydrophobic group, and its molecular formula is C a H b Cl2O6(C4H6) n , where a is 20 or 22, b is 20 or 24, and n is 2.7-8.

[0007] Furthermore, the long hydrophobic group is a polybutadiene group.

[0008] Furthermore, n is 2.7-4.2.

[0009] Furthermore, the molecular formula of polybutadiene liquid rubber is C 22 H 24 Cl2O6(C4H6) n , the structural formula is shown in Formula I,

[0010]

[0011] Furthermore, the molecular formula of polybutadiene liquid rubber is C 20 H 20 C l2 O6(C4H6) n , the structural formula is shown in Formula II,

[0012]

[0013] The second object of the present invention can be achieved by adopting the following technical solutions:

[0014] A method for preparing polybutadiene liquid rubber comprises the following steps: subjecting 2-(4-chloro-2-methylphenoxy) propionic acid to an ester exchange reaction with double-terminated hydroxyl polybutadiene to obtain double-terminated (R)-2-(4-chloro-2-methylphenoxy) propionate modified polybutadiene liquid rubber, the molecular formula of which is C 22 H 24 Cl2O6(C4H6) n , the structural formula is shown in Formula I:

[0015]

[0016] Furthermore, the mass ratio of 2-(4-chloro-2-methylphenoxy)propionic acid to double-terminated hydroxyl polybutadiene is 1:4-7.

[0017] Alternatively, a method for preparing polybutadiene liquid rubber comprises subjecting clofibric acid to an ester exchange reaction with double-terminated hydroxyl polybutadiene to obtain double-terminated (R)-2-(4-chlorophenoxy)-2-methylpropionate modified polybutadiene liquid rubber, the molecular formula of which is C 20 H 20 C l2 O6(C4H6) n , the structural formula is shown in Formula II:

[0018]

[0019] Furthermore, the mass ratio of clofibric acid to dihydroxy-terminated polybutadiene is 1:4-8.

[0020] Furthermore, the exchange reaction is carried out at a temperature of 160-200° C. for 6-10 hours.

[0021] The third object of the present invention can be achieved by adopting the following technical solution: an application of polybutadiene liquid rubber, wherein the polybutadiene liquid rubber is used to prepare a root inhibitor; the root inhibitor is applied below the roots of plants; the polybutadiene liquid rubber has a double-ended structure and a long hydrophobic group, and its molecular formula is C a H b Cl2O6(C4H6) n , where a is 20 or 22, b is 20 or 24, and n is 2.7-8.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The polybutadiene liquid rubber of this solution has a double-ended structure and a long hydrophobic group, which makes the product highly water-insoluble. The thermal migration problem of the root inhibitor is improved, greatly reducing the risk of water resource pollution caused by the migration of the root inhibitor;

[0024] 2. The preparation method of the polybutadiene liquid rubber of this scheme is simple, efficient and stable, and can be used for industrial production;

[0025] 3. The polybutadiene liquid rubber of this solution can be used to prepare root inhibitors, which not only have the effect of preventing roots, but also enhance the toughness and elasticity of the system and its low-temperature resistance, further improving the service life of the coiled material or liquid waterproof coating. DETAILED DESCRIPTION

[0026] Below, in conjunction with specific embodiments, the present invention is further described:

[0027] Polybutadiene liquid rubber is prepared by one of two methods:

[0028] 1) A method for preparing polybutadiene liquid rubber, comprising: conducting an ester exchange reaction between 2-(4-chloro-2-methylphenoxy) propionic acid and double-terminated hydroxyl polybutadiene at a temperature of 160-200°C and keeping the temperature for 6-10 hours, wherein the mass ratio of 2-(4-chloro-2-methylphenoxy) propionic acid to double-terminated hydroxyl polybutadiene is 1:4-7, and obtaining double-terminated (R)-2-(4-chloro-2-methylphenoxy) propionate modified polybutadiene liquid rubber, the molecular formula of which is C 22 H 24 Cl2O6(C4H6) n , n is 2.7-8, and the structural formula is shown in Formula I:

[0029]

[0030] 2) A method for preparing polybutadiene liquid rubber, comprising: conducting an ester exchange reaction between clofibric acid and dihydroxylated polybutadiene at a temperature of 160-200°C for 6-10 hours, wherein the mass ratio of clofibric acid to dihydroxylated polybutadiene is 1:4-8, to obtain dihydroxylated (R)-2-(4-chlorophenoxy)-2-methylpropionate modified polybutadiene liquid rubber having a molecular formula of C 20 H 20 C l2 O6(C4H6) n , n is 2.7-8, and the structural formula is shown in Formula II:

[0031]

[0032] The polybutadiene liquid rubber obtained by 1) or 2) is used to prepare a root inhibitor; the root inhibitor is prepared into a roll material or a coating and applied under the roots of plants.

[0033] Existing root inhibitors are typically prepared by direct esterification or alcoholysis using smaller molecular weight propanol, butanol, or octanol in the presence of a metal ion catalyst. This method is relatively mature. However, this method introduces metal ions during the preparation process. When the root inhibitor is subsequently applied to a coiled product, the metal ions can cause the coil to decompose, shortening its service life. Furthermore, the low molecular weight and varying hydrophobicity create the risk of precipitation and migration. Existing preparation methods also involve multiple synthesis steps and are time-consuming.

[0034] As a functional monomer derived from polybutadiene, dihydroxylated polybutadiene opens up new possibilities for the synthesis of functional materials. The double bonds in the dibutylene segments provide crosslinking groups, making root inhibitors formulated with polybutadiene liquid rubber risk-free. This mitigates thermal migration issues and, as a bonus, improves the toughness and low-temperature resistance of coils and coatings.

[0035] Example 1:

[0036] A method for preparing polybutadiene liquid rubber comprises the following steps: 457.2 g of 2-(4-chloro-2-methylphenoxy) propionic acid, a slightly excessive amount of 2713.2 g of double-terminated hydroxyl polybutadiene (hydroxyl value

[0037] 0.71-0.80mmol / g) and 0.8g hypophosphorous acid were placed in a three-necked round-bottom flask equipped with a reflux condenser, kept warm at 180°C for 8h, and vacuum-dehydrated for 2h to obtain a double-terminal (R)-2-(4-chloro-2-methylphenoxy) propionate-modified polybutadiene liquid rubber, the molecular formula of which is C 22 H 24 Cl2O6(C4H6) n , n=3; the structural formula is shown in Formula I:

[0038]

[0039] Yield 98.84%.

[0040] Example 2:

[0041] A method for preparing polybutadiene liquid rubber comprises the following steps: 457.2 g of 2-(4-chloro-2-methylphenoxy) propionic acid, a slightly excessive amount of 3484.8 g of double-terminated hydroxyl polybutadiene (hydroxyl value

[0042] 0.54-0.64mmol / g) and 0.8g hypophosphorous acid were placed in a three-necked round-bottom flask equipped with a reflux condenser, kept warm at 180°C for 8h, and vacuum-dehydrated for 2h to obtain a double-terminal (R)-2-(4-chloro-2-methylphenoxy) propionate-modified polybutadiene liquid rubber, the molecular formula of which is C 22 H 24 Cl2O6(C4H6) n , n=3.7; the structural formula is shown in Formula I:

[0043]

[0044] Yield 99.06%.

[0045] The reaction formula of Examples 1 and 2 is as shown in Formula III:

[0046]

[0047] Example 3:

[0048] A method for preparing polybutadiene liquid rubber comprises placing 429.2 g of chlorofibric acid (2-methyl-2-(p-chlorophenoxy)propionic acid), a slightly excessive amount of 2715 g of double-terminated hydroxyl polybutadiene (hydroxyl value 0.71-0.80 mmol / g), and 0.8 g of hypophosphorous acid in a three-necked round-bottom flask equipped with a reflux condenser, keeping the mixture at 180° C. for 8 h, and vacuum dehydrating the mixture for 2 h to obtain double-terminated (R)-2-(4-chlorophenoxy)-2-methylpropionic acid modified polybutadiene liquid rubber having the molecular formula C 20 H 20 C l2 O6(C4H6) n , n=3; the structural formula is shown in Formula II:

[0049]

[0050] Yield 98.85%.

[0051] The reaction formula of Example 3 is as Formula IV:

[0052]

[0053] Comparative Example:

[0054] 214.6g of clofibric acid (2-methyl-2-(p-chlorophenoxy)propionic acid), a slight excess of 149.6g of n-octanol, and 0.1g of hypophosphorous acid were placed in a three-necked round-bottom flask equipped with a reflux condenser. The mixture was incubated at 180°C for 8 hours, and then vacuum-dried to remove excess octanol for 2 hours. (R)-2-methyl-2-(p-chlorophenoxy)propionic acid octyl ester, a root inhibitor, was obtained with a yield of 84.56%. The comparative example represents a typical commercially available product.

[0055] Performance testing:

[0056] 1. Thermal stability test: 100 g of samples of Examples 1-3 and the comparative example were baked at 200°C for 4 h, and the weight change rate was %.

[0057] 2. Water resistance test: 100 g of samples of Examples 1-3 and the comparative example were added into water at 100°C for 2 hours, cooled, extracted, and dried. The weight change rate was %.

[0058] 3. Water-soluble amine or acid test: Test according to the national standard GB / T 259-1988 Determination of water-soluble acids and bases in petroleum products.

[0059] The final results are shown in Table 1:

[0060] Table 1 Thermal stability, water resistance and water-soluble amine or acid test results

[0061]

[0062] As can be seen from the table above, the thermal stability of the products in Examples 1-3 is superior to that of the comparative example, which exhibited precipitation of small molecule products. A water boiling test revealed a small amount of dissolution in the comparative example, suggesting the risk of migration and precipitation when used as a root inhibitor for waterproofing materials. Based on the weight change, Examples 1-3 showed no water solubility. Water solubility testing revealed that both the examples and the comparative example were neutral, lacking any water-soluble acid or base, thus eliminating the risk of precipitation and migration.

[0063] 4. Test of root barrier effect: Passing the FLL test chamber test is equivalent to working on the roof for 20 years

[0064] The polybutadiene liquid rubber prepared in Examples 1-3 was tested for its root barrier effect, including: the compounds prepared in Examples 1-3 were respectively prepared into root barrier solutions of the same concentration (4.2 mmol / L) using acetonitrile, and then the root barrier solutions were added to an FLL test box. The amount of root barrier solution was the same. The FLL test box contained the surface of the site or the top floor of the original building, an anti-leakage layer, a root barrier layer, a moisture-retaining layer, a drainage layer, a filter layer, a planting soil layer, and a dense plant cover layer. The root barrier solutions prepared with the polybutadiene liquid rubber in Examples 1-3 were placed under the roots of the plants, thereby generating growth stress from the roots. The plants were continuously fertilized and watered, and a controllable temperature was maintained to keep the experimental conditions consistent except for the type of root barrier, to avoid inaccurate test results due to insufficient water and fertilizer. The test period was 2 years. After the test, the planting soil layer was removed and the test root barrier solution was observed to see if any root puncture occurred. Among them, the root barrier test passed means that the roots did not pierce through the soil layer containing the root barrier solution, and the test failed means that the roots did pierce through the soil layer containing the root barrier solution. The results are shown in Table 2:

[0065] Table 2 Root barrier effect

[0066] example Concentration (mmol / L) Root barrier effect Plant growth status Example 1 4.2 pass good Example 2 4.2 pass good Example 3 4.2 pass good Comparative Example 1 4.2 pass good

[0067] The test results in Table 2 show that the root inhibitor compounds prepared in Examples 1-3, when used in appropriate dosages, can inhibit the main root system of the plant from absorbing surrounding nutrients and water, thereby achieving the effect of inhibiting the growth of the main root and promoting the growth of lateral roots, indicating that compounds with root inhibitory effects can be prepared according to the methods of Examples 1-3 of the present application.

[0068] 5. Coating performance:

[0069] Coating preparation method: TOCPOLY NH2421 aspartame polyurea resin and isocyanate curing agent TOCPOLYNC105B are mixed in a mass ratio of 1:2.6, and the root inhibitor is added in an amount of 5wt% of the total amount.

[0070] The root inhibitors prepared in Examples 1-3 and the comparative example were added to the aspartame polyurea elastic varnish to prepare coatings. Samples of 0.05 mm, 0.25 mm, 1.0 mm and 2.0 mm were prepared by a one-time coating method, and the samples were observed to see if there was local blistering.

[0071] Table 3 Coating performance test results

[0072]

[0073]

[0074] The test results in Table 3 above show that the root-blocking polyurea coatings in the examples of the present application have better application performance. For thick coatings with a thickness of 0.25 mm to 2.0 mm, they can be applied in one application, eliminating the need for multiple thin coatings. This makes application more convenient, efficient, and practical. The comparative example exhibited localized blistering at thicknesses above 1.0 mm.

[0075] 6. Mechanical properties:

[0076] Refer to GB / T 19250-2013 "Polyurethane Waterproof Coating" standard

[0077] The tensile strength and elongation at break of the coating prepared above were tested on samples with a coating thickness of 1.5 mm.

[0078] Table 4 Tensile strength and elongation at break of coatings

[0079] example Comparative Example Example 1 Example 2 Example 3 Blank not added Tensile strength, room temperature (MPa) 12.5 16.8 18.1 16.5 13.8 Elongation at break, room temperature (%) 310 380 383 385 320 Tensile strength, -30℃(MPa) 11.5 16.5 18.0 16.4 12.5 Elongation at break, -30℃(%) 295 375 380 380 310

[0080] According to the test results in Table 4, the tensile strength and elongation of the embodiment are improved compared with the blank group and the comparative example.

[0081] Those skilled in the art can make various other corresponding changes and modifications based on the technical solutions and concepts described above, and all of these changes and modifications should fall within the scope of protection of the claims of the present invention.

Claims

1. A polybutadiene liquid rubber, characterized in that: The polybutadiene liquid rubber has a double-ended structure and a long hydrophobic group, and its molecular formula is C a H b Cl2O6(C4H6) n , where a is 20 or 22, b is 20 or 24, and n is 2.7-8.

2. The polybutadiene liquid rubber according to claim 1, wherein The long hydrophobic group is a polybutadiene group.

3. The polybutadiene liquid rubber according to claim 1, wherein The molecular formula of the polybutadiene liquid rubber is C 22 H 24 Cl2O6(C4H6) n , the structural formula is shown in Formula I:

4. The polybutadiene liquid rubber according to claim 1, wherein The molecular formula of the polybutadiene liquid rubber is C 20 H 20 C l2 O6(C4H6) n , the structural formula is shown in Formula II:

5. A method for preparing polybutadiene liquid rubber, characterized in that: The double-terminal (R)-2-(4-chloro-2-methylphenoxy) propionic acid and double-terminal hydroxyl polybutadiene were subjected to ester exchange reaction to obtain double-terminal (R)-2-(4-chloro-2-methylphenoxy) propionate modified polybutadiene liquid rubber, the molecular formula of which is C 22 H 24 Cl2O6(C4H6) n , the structural formula is shown in Formula I, 6. The method for preparing polybutadiene liquid rubber according to claim 5, wherein: The mass ratio of 2-(4-chloro-2-methylphenoxy)propionic acid to double-terminated hydroxyl polybutadiene is 1:4-7.

7. A method for preparing polybutadiene liquid rubber, characterized in that: The clofibric acid and double-terminated hydroxyl polybutadiene were subjected to ester exchange reaction to obtain double-terminated (R)-2-(4-chlorophenoxy)-2-methylpropionate modified polybutadiene liquid rubber, the molecular formula of which is C 20 H 20 C l2 O6(C4H6) n , the structural formula is shown in Formula II, 8. The method for preparing polybutadiene liquid rubber according to claim 7, wherein: The mass ratio of the clofibric acid to the double-terminated hydroxyl polybutadiene is 1:4-8.

9. The method for preparing polybutadiene liquid rubber according to claim 5 or 7, wherein: The exchange reaction is carried out at a temperature of 160-200° C. for 6-10 hours.

10. An application of polybutadiene liquid rubber, characterized in that: The polybutadiene liquid rubber is used to prepare a root inhibitor; the root inhibitor is applied below the roots of plants; the polybutadiene liquid rubber has a double-ended structure and a long hydrophobic group, and its molecular formula is C a H b Cl2O6(C4H6) n , where a is 20 or 22, b is 20 or 24, and n is 2.7-8.

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