Hydrophobic monomer for thickener, preparation method and application

Abstract

The present invention relates to the technical field of waterborne coatings, and discloses a hydrophobic monomer for a thickener, a preparation method, and an application. The monomer is present as a Y-type modified monomer, including a hydrophilic segment and two hydrophobic segments; the raw material components are measured by weight, including 2 mol of saturated fatty acid, 1 mol of a Y-type crosslinking monomer, 1 mol of a diisocyanate, and 1 mol of APEG. The hydrophobic monomer for a thickener provided by the present invention is composed of a hydrophilic segment and two hydrophobic segments, and the hydrophilic chain can achieve water solubility, so that the hydrophobic segment has a larger range of activities in the coating system, and a network structure is formed by association; the two hydrophobic segments provide more anchoring points in the coating system, and the association is stronger.

Description

Technical Field

[0001] The invention relates to the technical field of water-based coatings, and in particular to a hydrophobic monomer for a thickener, a preparation method and an application thereof. Background Art

[0002] Thickener is a rheological additive used to adjust the viscosity of the system. It can increase the viscosity of the system at low shear rates, but has little effect on the viscosity of the system at high shear rates.

[0003] With the increasingly severe environmental situation, countries have set higher and higher standards for the coatings industry, which has promoted the development of water-based coatings. In this process, thickeners have developed rapidly and gradually become a kind of functional polymer material with a wide range of applications.

[0004] After adding thickener to water-based paint, it can not only increase the viscosity of the system, but also give the water-based paint excellent storage stability and mechanical properties, and play a role in controlling rheology and preventing sagging during the construction of water-based paint. These excellent properties have further promoted the continuous innovation of thickeners.

[0005] As the thickener with the largest amount of usage in water-based coatings, alkali swelling thickeners have gradually developed from non-associative alkali swelling thickeners to associative alkali swelling thickeners, i.e., hydrophobically modified alkali swelling thickeners. Currently, the commonly used hydrophobically modified monomers are long-chain alkyl alcohol polyoxyethylene ether methacrylate (BEM) and triphenyl phenol polyoxyethylene ether methacrylate (SEM-25). The BEM-modified alkali swelling thickener has high thickening efficiency for water, but poor thickening effect for emulsions, and average thickening effect under medium and high shear forces. The hydrophobic group of SEM-25 is triphenyl phenol containing polyvalent benzene rings, which has poor flexibility and affects thickening efficiency. It has a good thickening effect on styrene-acrylic emulsions and is resistant to high shear, but has weak thickening ability for water. Summary of the invention

[0006] <Technical Problems Solved by the Invention>

[0007] It is used to solve the problem that traditional hydrophobic modified materials cannot simultaneously meet the thickening efficiency of water and styrene-acrylic emulsion.

[0008] <Technical solution adopted by the present invention>

[0009] In view of the above technical problems, the object of the present invention is to provide a hydrophobic monomer for a thickener, a preparation method and an application thereof.

[0010] First, the present invention provides a hydrophobic monomer for a thickener, which is a Y-shaped modified monomer, including a hydrophilic segment and two hydrophobic segments; the raw material components, calculated by weight, include 2 mol of saturated fatty acid, 1 mol of Y-shaped cross-linking monomer, 1 mol of diisocyanate, and 1 mol of APEG.

[0011] Second, the present invention provides a method for preparing the aforementioned hydrophobic monomer for thickener, comprising the following steps:

[0012] S1 saturated fatty acid is blended with Y-type cross-linking monomer to undergo esterification and dehydration reaction;

[0013] After S2 reacts, add diisocyanate dropwise and keep warm after the addition is complete;

[0014] S3 then adds APEG, raises the temperature, and keeps the temperature until NCO reacts completely, and dilutes with an active diluent to obtain a monomer.

[0015] Thirdly, the present invention provides a use of the aforementioned hydrophobic monomer for thickener in water-based coatings.

[0016] The specific contents are as follows:

[0017] <Technical mechanism and beneficial effects of the present invention>

[0018] The hydrophobic monomer for thickener provided by the present invention is composed of a hydrophilic segment and two hydrophobic segments. The hydrophilic chain can achieve water solubility, so that the hydrophobic segment has a larger range of activity in the coating system and forms a network structure through association. The two hydrophobic segments provide more anchoring points in the coating system, and the association is stronger. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0020] First, the present invention provides a hydrophobic monomer for a thickener, which is a Y-shaped modified monomer, including a hydrophilic segment and two hydrophobic segments; the raw material components, calculated by weight, include 2 mol of saturated fatty acid, 1 mol of Y-shaped cross-linking monomer, 1 mol of diisocyanate, and 1 mol of APEG.

[0021] In the present invention, the saturated fatty acid includes at least one of caprylic acid, isooctanoic acid, nonanoic acid, isononanoic acid, capric acid, lauric acid (dodecanoic acid), palmitic acid (tetradecanoic acid), palmitic acid (hexadecanoic acid), and stearic acid (octadecanoic acid).

[0022] In the present invention, the diisocyanate includes at least one of toluene diisocyanate, hexamethylene diisocyanate and isophorone diisocyanate.

[0023] The present invention further comprises a reactive diluent, which comprises at least one of acrylic acid, methacrylic acid, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate and butyl methacrylate.

[0024] In the present invention, the Y-type crosslinking monomer is a monomer containing three segments in the molecule and a hydroxyl group at the end of each segment; the Y-type crosslinking monomer includes at least one of trimethylolpropane and glycerol.

[0025] In the present invention, APEG may specifically be APEG-500, APEG-700, APEG-900, APEG-1200, or APEG-2400.

[0026] In the present application, the synergistic thickening mechanism is mainly composed of alkali neutralization thickening, hydrogen bond thickening, and hydrophobic segment associative thickening. Alkali neutralization thickening is that a large number of carboxyl groups on the polymer chain are neutralized by alkali to form salts, and the electrostatic repulsion generated within the molecule causes the macromolecular structure to gradually stretch from a curled state, thereby increasing the viscosity of the system. Hydrogen bond thickening is that the hydrophilic chains in the macromolecules adsorb free water through hydrogen bonds, reducing free water and increasing the viscosity of the system. Hydrophobic segment associative thickening is that a large number of hydrophobic segments in the stretched macromolecules, in addition to adsorbing each other, are also adsorbed by latex particles and pigment filler particles, forming a large-scale network structure, and the viscosity of the system increases.

[0027] Second, the present invention provides a method for preparing the aforementioned hydrophobic monomer for thickener, comprising the following steps:

[0028] S1 saturated fatty acid is blended with Y-type cross-linking monomer to undergo esterification and dehydration reaction;

[0029] After S2 reacts, add diisocyanate dropwise and keep warm after the addition is complete;

[0030] S3 then adds APEG, raises the temperature, and keeps the temperature until NCO reacts completely, and dilutes with an active diluent to obtain a monomer.

[0031] In the present invention,

[0032] In S1, the reaction temperature is 160-200°C, and after the reaction, the temperature is lowered to 40-70°C;

[0033] In S2, the dropping time is 20 to 60 minutes, and the heat preservation time is 40 to 100 minutes;

[0034] In S3, the temperature is raised to 60-85°C, and after the reaction, the temperature is lowered to 40-70°C.

[0035] Thirdly, the present invention provides a use of the aforementioned hydrophobic monomer for thickener in water-based coatings.

[0036] <Example>

[0037] Example 1

[0038] 2 mol of lauric acid and 1 mol of glycerol were put into a four-necked flask, stirred and heated to 180°C, and esterification and dehydration reaction was carried out until the lauric acid was completely reacted. After the reaction was completed, the temperature was lowered to 50°C, and 1 mol of hexamethylene diisocyanate was added dropwise for 30 minutes and kept warm for 1 hour. Then APEG-900 was added, the temperature was raised to 70°C, and kept warm until NCO was completely reacted, the temperature was lowered to 50°C, and methacrylic acid was used to dilute the solid content to 68-70 (by weight percentage, %), and the finished product 1 was obtained.

[0039] Example 2

[0040] 2 mol of isooctanoic acid and 1 mol of trimethylolpropane were put into a four-necked flask, stirred and heated to 180°C, and esterification and dehydration reaction was carried out until the isooctanoic acid was completely reacted. After the reaction was completed, the temperature was lowered to 50°C, and 1 mol of toluene diisocyanate was added dropwise for 30 minutes and kept warm for 1 hour. Then APEG-500 was added, the temperature was raised to 70°C, and kept warm until NCO was completely reacted, the temperature was lowered to 50°C, and the solid content was diluted with acrylic acid to 68-70 (by weight percentage, %), and the finished product 2 was obtained.

[0041] Example 3

[0042] 2 mol of stearic acid and 1 mol of trimethylolpropane were put into a four-necked flask, stirred and heated to 180°C, and esterification and dehydration reaction was carried out until the isooctanoic acid was completely reacted. After the reaction was completed, the temperature was lowered to 50°C, and 1 mol of isophorone diisocyanate was added dropwise for 30 minutes and kept warm for 1 hour. Then APEG-2400 was added, the temperature was raised to 70°C, and kept warm until NCO was completely reacted, the temperature was lowered to 50°C, and methacrylic acid was diluted to 68-70 (by weight percentage, %) to obtain the finished product 3.

[0043] Example 4

[0044] 2 mol of lauric acid and 1 mol of trimethylolpropane were put into a four-necked flask, stirred and heated to 180°C, and esterification and dehydration reaction was carried out until the isooctanoic acid was completely reacted. After the reaction was completed, the temperature was lowered to 50°C, and 1 mol of toluene diisocyanate was added dropwise for 30 minutes and kept warm for 1 hour. Then APEG-1200 was added, the temperature was raised to 70°C, and kept warm until NCO was completely reacted, the temperature was lowered to 50°C, and methacrylic acid was diluted to 68-70 (by weight percentage, %) to obtain the finished product 4.

[0045] <Test example>

[0046] The finished products 1-4 prepared in the examples are test samples 1-4 (E1-E4), BEM is comparison sample 1 (D1), and SEM-25 is comparison sample 2 (D2).

[0047] The aforementioned sample was added to other components to prepare a thickener (see Table 1), and the performance of the thickener was measured. The results are shown in Table 2.

[0048] The thickener synthesis process includes pre-emulsion preparation, initiator solution preparation and synthesis reaction.

[0049] Preparation of pre-emulsion: add 30 parts of deionized water, 0.5 parts of sodium lauryl sulfate, and 0.5 parts of OP-10 to the pre-emulsification kettle, stir for 10 minutes, then add 11.25 parts of methacrylic acid, 18 parts of ethyl acrylate, and 0.5 parts of monomer in sequence, and pre-emulsify for more than 30 minutes;

[0050] Preparation of initiator solution: 5 parts of deionized water, 0.05 parts of ammonium persulfate, stir evenly;

[0051] Synthesis reaction: add 34 parts of deionized water, 0.1 parts of sodium dodecyl sulfate, and 0.1 parts of OP-10 into the reactor, stir and heat to 80-85°C, and simultaneously add the pre-emulsion and initiator solution dropwise. The pre-emulsion is added for 3 hours, and the initiator is added for 3.2 hours. After the addition is completed, keep warm at 80-85°C for 1 hour, cool to 45°C, filter and package, and the thickener is prepared.

[0052]

[0053]

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A hydrophobic monomer for a thickener, characterized in that: The monomer exists as a Y-shaped modified monomer, including a hydrophilic segment and two hydrophobic segments; The raw material components are calculated by mole, including 2 mol of saturated fatty acid, 1 mol of Y-type cross-linking monomer, 1 mol of diisocyanate, and 1 mol of APEG; The Y-type crosslinking monomer is a monomer containing three segments in the molecule and a hydroxyl group at the end of each segment; the Y-type crosslinking monomer includes at least one of trimethylolpropane and glycerol; The preparation method of the hydrophobic monomer for thickener comprises the following steps: S1: saturated fatty acid is mixed with Y-type cross-linking monomer to undergo esterification and dehydration reaction; After S2 reacts, add diisocyanate dropwise and keep warm after the addition is complete; S3: Add APEG, raise the temperature, and keep warm until NCO reacts completely, and dilute with active diluent to obtain a monomer.

2. The hydrophobic monomer for thickener according to claim 1, characterized in that The saturated fatty acid includes at least one of caprylic acid, isooctanoic acid, nonanoic acid, isononanoic acid, capric acid, lauric acid, palmitic acid, palmitic acid, and stearic acid.

3. The hydrophobic monomer for thickener according to claim 1, characterized in that: The diisocyanate includes at least one of toluene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate.

4. The hydrophobic monomer for thickener according to claim 1, characterized in that The invention also includes a reactive diluent, which includes at least one of acrylic acid, methacrylic acid, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate and butyl methacrylate.

5. The hydrophobic monomer for thickener according to any one of claims 1 to 4, characterized in that: APEG includes APEG-500, APEG-700, APEG-900, APEG-1200, and APEG-2400.

6. The hydrophobic monomer for thickener according to claim 1, characterized in that: In S1, the reaction temperature is 160-200°C, and after the reaction, the temperature is lowered to 40-70°C; In S2, the dropping time is 20-60 min, and the holding time is 40-100 min; In S3, the temperature is raised to 60-85°C, and then lowered to 40-70°C after the reaction.

7. Use of the hydrophobic monomer for thickener according to any one of claims 1 to 6 in water-based coatings.

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