Preparation method and application of a hyperdispersant

Abstract

The present invention relates to the technical field of hyperdispersants, particularly to the field of IPC C08L23, and further to a method for preparing and applying a hyperdispersant. The method comprises at least the following steps: (1) adding a hydroxy acid, a solvent, and a catalyst to a reactor equipped with a water separator to carry out an esterification reaction; and (2) tracking the reaction using infrared absorption spectroscopy. When the acid value reaches 70 to 90 mg KOH / g, a capping agent is added, and the reaction is carried out at a temperature of 20 to 40 mg KOH / g, followed by cooling and vacuum distillation. The hyperdispersant prepared by the present invention can not only improve the dispersibility of pigments in plastic systems, but also enhance the tinting strength of the pigments.

Description

Technical Field

[0001] The present invention relates to the technical field of hyperdispersants, in particular to the field of IPC C08L23, and further to a preparation method and application of a hyperdispersant. Background Art

[0002] In our daily lives, colorful plastic products can be seen everywhere. This is because various pigments are added to plastic products. However, due to the incompatibility between pigments and polymers, problems such as uneven color or reduced tinting strength usually occur.

[0003] Chinese patent CN 201710251688 discloses a polycarboxylic acid-based hyperdispersant and its preparation method and application, comprising the following steps: 30 to 50 parts by weight of methoxypolyethylene glycol monomethyl ether, 10 to 20 parts by weight of unsaturated carboxylic acid, and 40 to 50 parts by weight of other ethylenically unsaturated monomers are prepared into a 20% to 50% aqueous solution, and an emulsifier, initiator, and chain transfer agent are added under normal pressure and nitrogen protection to react at a temperature of 50 to 100°C for 5 to 8 hours. The pH value is then adjusted to 7 to 8 with alkaline solution, and a powdered product is obtained by spray drying. This product can be directly used in composite materials of ABS and calcium carbonate, increasing the filling amount of calcium carbonate in ABS, thereby reducing the shrinkage rate and thermal expansion coefficient of ABS, having better physical and mechanical properties, and reducing the production cost of ABS products.

[0004] Chinese patent CN 114874380 A discloses a method for preparing a hyperdispersant and its use in titanium dioxide masterbatch. The preparation method comprises dissolving an initiator, a solvating chain, a chain transfer agent, and an anchoring segment in ethylene glycol methyl ether, heating to 65-85°C with stirring, reacting for 4-6 hours, cooling to below 45°C, filtering, washing, and drying to obtain the hyperdispersant. This method synthesizes the hyperdispersant through free radical solution polymerization and uses it to modify the surface of inorganic nanoparticles to improve their dispersibility in the polymer.

[0005] However, the dispersant prepared by the above technical solution is only suitable for specific pigments such as calcium carbonate or titanium dioxide, and has a relatively small application range. Summary of the Invention

[0006] A first aspect of the present invention provides a method for preparing a hyperdispersant, comprising at least the following steps:

[0007] (1) adding hydroxy acid, solvent, and catalyst into a reactor equipped with a water separator to carry out esterification reaction;

[0008] (2) The reaction was tracked by infrared absorption spectroscopy. When the acid value reached 70-90 mg KOH / g, a capping agent was added and the reaction was kept warm until the acid value reached 20-40 mg KOH / g. The temperature was then lowered and the distillation was performed under reduced pressure.

[0009] (3) Raise the temperature and add low molecular weight wax, stir and mix evenly, and finally cool to obtain the product.

[0010] In some preferred embodiments, the hydroxy acid is an aliphatic hydroxy acid having 8 to 18 carbon atoms.

[0011] Preferably, the hydroxy acid is an aliphatic hydroxy acid having 12 to 18 carbon atoms.

[0012] Preferably, the aliphatic hydroxy acid having 12 to 18 carbon atoms is at least one selected from 12-hydroxystearic acid, 12-hydroxylauric acid, and 16-hydroxypalmitic acid.

[0013] Preferably, the aliphatic hydroxy acid having 12 to 18 carbon atoms is 12-hydroxystearic acid.

[0014] In some preferred embodiments, the solvent is selected from one or a combination of solvent oil or ester solvents.

[0015] Preferably, the solvent is solvent oil.

[0016] Preferably, the solvent oil is selected from one or more combinations of paraffin solvent oil, cycloparaffin solvent oil, and aromatic solvent oil.

[0017] Preferably, the solvent oil is D80.

[0018] In some preferred embodiments, the catalyst is selected from at least one of stannous chloride, dibutyltin dilaurate, stannous octoate, stannous oleate, p-toluenesulfonic acid, and aminobenzenesulfonic acid.

[0019] Preferably, the catalyst is stannous chloride.

[0020] In some preferred embodiments, the mass ratio of the hydroxy acid, the solvent, and the catalyst is (50-70): (5-7): (0.05-0.2).

[0021] Preferably, the mass ratio of the hydroxy acid, the solvent, and the catalyst is 60:6:0.075.

[0022] In some preferred embodiments, the end-capping agent is selected from at least one of octanol, isooctyl alcohol, butanol, isobutanol, amyl alcohol, isopentanol, nonanol, and isononanol.

[0023] Preferably, the capping agent is isooctyl alcohol.

[0024] In some preferred embodiments, the amount of the capping agent is 10-15% of the mass of the hydroxy acid.

[0025] In some preferred embodiments, steps (1) and (2) are both performed in a nitrogen protective atmosphere.

[0026] In some preferred embodiments, the esterification reaction in step (1) is carried out at a temperature of 150 to 180° C. and for a time of 6 to 9 hours.

[0027] Preferably, the temperature of the esterification reaction in step (1) is 170° C. and the time is 7 hours.

[0028] In some preferred embodiments, the insulation reaction time in step (2) is 4 to 8 hours.

[0029] In some preferred embodiments, the cooling temperature in step (2) is 100°C.

[0030] In some preferred embodiments, the low molecular weight wax is selected from one or a combination of polyethylene wax, polypropylene wax, oxidized polyethylene wax, and EVA (ethylene-vinyl acetate copolymer) wax.

[0031] Preferably, the low molecular weight wax is polyethylene wax.

[0032] Preferably, the number average molecular weight of the polyethylene wax is 2000-5000.

[0033] Through a large number of creative experiments, the inventors found that in the system of the present invention, when the hydroxy acid is 12-hydroxystearic acid, isooctyl alcohol is used as a capping agent, and the solvent is solvent oil, especially when the mass ratio of the hydroxy acid, the solvent, and the catalyst is 60:6:0.075; and the low molecular weight wax is a polyethylene wax with a number average molecular weight of 2000 to 5000, the pigment dispersion can be improved while also improving the tinting strength and brightness of the pigment. The inventors speculate that on the one hand, when the hydroxy acid is 12-hydroxystearic acid, isooctyl alcohol is used as a capping agent, the solvent is solvent oil, and the mass ratio of hydroxy acid, solvent, and catalyst is 60:6:0.075, the prepared terminal hydroxyl polyhydroxystearate has a higher lipophilicity, and the hyperdispersant forms a thicker adsorption layer on the pigment surface, thereby providing sufficient steric hindrance, which not only improves the compatibility of the pigment with the plastic polymer matrix, but also improves the dispersibility of the pigment in the plastic polymer matrix; on the other hand, when polyethylene wax with a number average molecular weight of 2000 to 5000 is added, the prepared hyperdispersant can better wet the pigment during the plastic processing process, improve the miscibility of the pigment, and facilitate the uniform dispersion of the pigment, thereby improving the tinting strength and brightness of the pigment.

[0034] In some preferred embodiments, the amount of the low molecular weight wax is 20-60% by mass of the hydroxy acid.

[0035] In some preferred embodiments, the heating temperature in step (3) is 110-140°C.

[0036] In some preferred embodiments, the stirring and mixing time in step (3) is 0.5 to 2 hours.

[0037] A second aspect of the present invention provides an application of a hyperdispersant obtained according to the above-mentioned method for preparing a hyperdispersant, wherein the hyperdispersant is used to disperse pigments in a plastic system.

[0038] Preferably, the amount of the hyperdispersant added to the plastic system is 2-10% of the pigment mass.

[0039] Beneficial effects:

[0040] 1. In the present invention, when the mass ratio of hydroxy acid, solvent and catalyst is controlled to be (50-70): (5-7): (0.05-0.2), especially when the mass ratio of hydroxy acid, solvent and catalyst is 60:6:0.075, the reaction rate is accelerated while avoiding the occurrence of side reactions, and the adsorption effect of the hyperdispersant on the pigment surface is enhanced, thereby improving the dispersibility.

[0041] 2. In the present invention, when the solvent is solvent oil, especially when the solvent oil is D80, the reaction speed is increased, and the solubility of the reaction intermediate is good, and it is non-toxic, non-irritating and safe.

[0042] 3. In the present invention, when the hydroxy acid is 12-hydroxystearic acid, isooctyl alcohol is used as a capping agent, and the amount of the capping agent is 10-15% of the mass of the hydroxy acid; and the low molecular weight wax is a polyethylene wax with a number average molecular weight of 2000-5000, the pigment dispersion can be improved while also improving the tinting strength and brightness of the pigment.

[0043] 4. In the present invention, the temperature of the esterification reaction in step (1) is controlled to be 150-180°C and the time is 6-9 hours. In particular, when the temperature of the esterification reaction in step (1) is 170°C and the time is 7 hours, side reactions can be avoided, the molecular weight of the prepared polymer is within a moderate range, and the dispersibility of the hyperdispersant is improved.

[0044] 5. In the present invention, the amount of the hyperdispersant added to the plastic system is controlled to be 2 to 10% of the pigment mass, thereby improving the dispersibility and tinting strength of the pigment in the plastic system. DETAILED DESCRIPTION

[0045] Example 1

[0046] Example 1 provides a method for preparing a hyperdispersant, comprising the following steps:

[0047] (1) Add 60 g of 12-hydroxystearic acid, 6 g of solvent oil, and 0.1 g of stannous chloride into a reactor equipped with a water separator to carry out an esterification reaction;

[0048] (2) The reaction was tracked by infrared absorption spectroscopy. When the acid value reached 85 mg KOH / g, 7.12 g of isooctyl alcohol was added and the reaction was kept warm until the acid value reached 28 mg KOH / g. The temperature was then lowered to 100°C and distilled under reduced pressure.

[0049] (3) Heat to 120°C, add 25.7 g of polyethylene wax, stir and mix evenly for 1 hour, and finally cool.

[0050] The solvent oil is D80, Shanghai MacLean Biochemical Technology Co., Ltd.

[0051] The steps (1) and (2) are both carried out in a nitrogen protective atmosphere.

[0052] The temperature of the esterification reaction in step (1) is 160° C. and the time is 8 hours.

[0053] The insulation reaction time in step (2) is 7 hours.

[0054] The polyethylene wax has a number average molecular weight of 2300 and is purchased from Clariant Chemicals GmbH, Germany, with a model number of PE520.

[0055] An application of a hyperdispersant obtained according to the preparation method of the hyperdispersant is used for dispersing Pigment Red 48:2 in a plastic system.

[0056] Performance testing:

[0057] (1) Determination of pigment color and tinting strength:

[0058] Mix 0.2g of Pigment Red 48:2, 2mL of dizinc phthalate, 0.006g of hyperdispersant, and 60g of PVC (polyvinyl chloride). Preheat the plasticizer to 130°C, set the roller spacing to 0.15mm, and start the two-roller mill. Pour the mixed material between the rollers, start the milling timer for 7 minutes, stop the mill, and remove the material. After vulcanization, perform a colorimetric test. Cut 35g of the above-mentioned pellet with scissors, add 0.77g of titanium dioxide, mix for 5 minutes, and remove the pellet. After vulcanization, perform a colorimetric test.

[0059] Set the vulcanizer temperature to 160°C, the pressure to 13.5-14 MPa, and the curing time to 40 seconds. Cut the homogenized sample and standard into small pieces, 4 cm wide and 6 cm long. Place the cut sample and standard side by side, facing upwards, on a metal plate. Add a metal frame, cover with another metal plate, and place between the two plates of the vulcanizer. Close the pressure valve and start the motor to begin curing. After the specified time has expired, cool the sample, remove the sample, and test the color and color strength using a colorimeter.

[0060] (2) Pigment dispersion determination:

[0061] Weigh 20g of Pigment Red 48:2 and 30g of polyethylene wax into a glass bottle, place it in a 140℃ oven and bake for 2h. After cooling, pour the baked material into a small powder machine and grind it into powder.

[0062] 187.5 g of polypropylene resin, 12.5 g of a crushed pigment and polyethylene wax mixture were weighed, 0.4 g of a hyperdispersant was added and mixed to obtain a material to be tested.

[0063] Turn on the filtration performance tester, keep the temperature for 30 minutes after it reaches the set temperature, press the frequency conversion power on button, and turn on the circulating water pump switch at the same time.

[0064] Add polypropylene into the hopper to clean the machine. After the pressure behind the pump stabilizes, record the equilibrium pressure P. s , pour the weighed material into the hopper, add polypropylene resin after all the samples enter the screw and push out all the remaining materials, so that the pressure in front of the screen reaches equilibrium, and record the pressure value P max .

[0065] Filter pressure value: △P=(P max -P s ) / M c

[0066] P s :Starting pressure (bar)

[0067] P max :Maximum pressure (bar)

[0068] M c :Amount of pigment used (g)

[0069] Test results:

[0070] Table 1

[0071]

[0072] Table 2

[0073] Pigment Red 48:2 No hyperdispersant added Adding hyperdispersant Filtration pressure (bar / g) 3.06 1.14

[0074] Example 2

[0075] Example 2 provides a method for preparing a hyperdispersant, comprising the following steps:

[0076] (1) 60 g of 12-hydroxystearic acid, 6 g of solvent oil, and 0.075 g of stannous chloride were added to a reactor equipped with a water separator to carry out an esterification reaction;

[0077] (2) The reaction was tracked by infrared absorption spectroscopy. When the acid value reached 83 mg KOH / g, 7.125 g of isooctyl alcohol was added and the reaction was kept warm until the acid value reached 30 mg KOH / g. The temperature was then lowered to 100°C and distilled under reduced pressure.

[0078] (3) Heat to 130°C, add 34.2g of polyethylene wax, stir and mix evenly for 1h, and finally cool.

[0079] The solvent oil is D80.

[0080] The steps (1) and (2) are both carried out in a nitrogen protective atmosphere.

[0081] The temperature of the esterification reaction in step (1) is 170° C. and the time is 7 hours.

[0082] The insulation reaction time in step (2) is 5 hours.

[0083] The polyethylene wax has a number average molecular weight of 3000-4500 and is purchased from Honeywell (China) Co., Ltd. with a model number of AC-6A.

[0084] An application of a hyperdispersant obtained according to the preparation method of the hyperdispersant is used to disperse Pigment Yellow 83 in a plastic system.

[0085] Performance testing:

[0086] The test method is the same as that of Example 1, except that when testing the pigment shade and tinting strength, the amount of hyperdispersant is 0.01 g; when testing the pigment dispersibility, the amount of hyperdispersant is 0.5 g.

[0087] Test results:

[0088] Table 3

[0089]

[0090] Table 4

[0091] Pigment Yellow 83 No hyperdispersant added Adding hyperdispersant Filtration pressure (bar / g) 2.66 0.98

[0092] Example 3

[0093] Example 3 provides a method for preparing a hyperdispersant, comprising the following steps:

[0094] (1) 60 g of 12-hydroxystearic acid, 6 g of solvent oil, and 0.075 g of stannous chloride were added to a reactor equipped with a water separator to carry out an esterification reaction;

[0095] (2) The reaction was tracked by infrared absorption spectroscopy. When the acid value reached 83 mg KOH / g, 7.12 g of isooctyl alcohol was added and the reaction was kept warm until the acid value reached 30 mg KOH / g. The temperature was then lowered to 100°C and distilled under reduced pressure.

[0096] (3) Heat to 130°C, add 17.1 g of polyethylene wax, stir and mix evenly for 1 hour, and finally cool.

[0097] The solvent oil is D80.

[0098] The steps (1) and (2) are both carried out in a nitrogen protective atmosphere.

[0099] The temperature of the esterification reaction in step (1) is 170° C. and the time is 7 hours.

[0100] The insulation reaction time in step (2) is 5 hours.

[0101] The polyethylene wax has a number average molecular weight of 2300 and is purchased from Clariant Chemicals GmbH, Germany, with a model number of PE520.

[0102] An application of a hyperdispersant obtained according to the preparation method of the hyperdispersant is used to disperse pigment blue 15:3 in a plastic system.

[0103] Performance testing:

[0104] The test method is the same as that of Example 1, except that when testing the pigment shade and tinting strength, the amount of hyperdispersant is 0.01 g; when testing the pigment dispersibility, the amount of hyperdispersant is 0.5 g.

[0105] Test results:

[0106] Table 5

[0107]

[0108] Table 6

[0109] Pigment Blue 15:3 No hyperdispersant added Adding hyperdispersant Filtration pressure (bar / g) 4.32 1.02

[0110] Comparative Example 1

[0111] Comparative Example 1 provides a method for preparing a hyperdispersant, and its specific implementation method is the same as that of Example 3, except that there is no step (3).

[0112] Performance test: The test method is the same as that in Example 3.

[0113] Test results:

[0114] Table 7

[0115]

[0116] Table 8

[0117] Pigment Blue 15:3 No hyperdispersant added Adding hyperdispersant Filtration pressure (bar / g) 4.32 2.65

[0118] Comparative Example 2

[0119] Comparative Example 2 uses polyethylene wax as a dispersant to disperse Pigment Blue 15:3 in a plastic system.

[0120] Performance test: The test method is the same as that in Example 3.

[0121] Test results:

[0122] Table 9

[0123]

[0124] Table 10

[0125] Pigment Blue 15:3 No dispersant added Add dispersant Filtration pressure (bar / g) 4.32 3.30

Claims

1. A method for preparing a hyperdispersant, characterized in that: At least the following steps are included: (1) Adding hydroxy acid, solvent and catalyst into a reactor equipped with a water separator to carry out esterification reaction; (2) The reaction was tracked by infrared absorption spectroscopy. When the acid value was 70-90 mg KOH / g, a capping agent was added and the reaction was kept warm until the acid value reached 20-40 mg KOH / g. The temperature was then lowered and vacuum distillation was performed. (3) Heat the mixture and add low molecular weight wax, stir and mix evenly, and finally cool. The low molecular weight wax is polyethylene wax, and the number average molecular weight of the polyethylene wax is 2000 to 5000; The end-capping agent is selected from at least one of octanol, butanol, pentanol, and nonanol; The solvent is selected from one or a combination of solvent oil or ester solvents; The mass ratio of the hydroxy acid, solvent and catalyst is 60:6:0.075; The esterification reaction in step (1) is carried out at a temperature of 150-180°C and for a time of 6-9 hours; The hydroxy acid is an aliphatic hydroxy acid having 8 to 18 carbon atoms.

2. The method for preparing a hyperdispersant according to claim 1, wherein The solvent oil is selected from one or more combinations of paraffin solvent oil, cycloparaffin solvent oil, and aromatic solvent oil.

3. The method for preparing a hyperdispersant according to any one of claims 1 to 2, wherein The heating temperature in step (3) is 110-140°C.

4. The method for preparing a hyperdispersant according to claim 3, wherein The heat preservation reaction time in step (2) is 4 to 8 hours.

5. Use of a hyperdispersant obtained by the method for preparing a hyperdispersant according to any one of claims 1 to 4, characterized in that: A hyperdispersant is used to disperse the pigment in the plastic system; the amount of the hyperdispersant added to the plastic system is 2-10% of the pigment mass.

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