A urea-based dispersant, its preparation method and application

Abstract

This invention discloses a urea-based dispersant, its preparation method, and its application. The urea-based dispersant comprises the following two components by weight: 50-70 parts of a urea-based polymer and 30-50 parts of a diluent. The urea-based polymer is prepared by chemical reaction of the following components by weight: 37.3-52.8 parts of isocyanate biuret or trimer, 11.8-26.4 parts of n-decylamine, and 25.0-44.8 parts of castor oil acid. The isocyanate biuret or trimer is selected from at least one of isocyanate biuret and isocyanate trimer. Each molecular chain segment of the isocyanate biuret or trimer contains n -NCO groups, where n is 2 or 3, or any value between 2 and 3. The urea-based dispersant can be applied in coatings, rubber, plastics, and other fields. Special functional groups such as urea groups, carboxyl groups, and aliphatic long carbon chains can simultaneously and effectively disperse organic pigments, inorganic pigments, and fillers.

Description

Technical Field

[0001] This invention relates to the chemical industry, and in particular to a urea-based dispersant, its preparation method, and its application. Background Technology

[0002] Dispersants are additives that disperse various organic and inorganic pigments and fillers to prevent the aggregation and sedimentation of solid pigment and filler particles. Dispersants often contain special groups such as carboxyl groups (-COOH) and urea groups (R-NH-CO-NH-R′). Carboxyl groups have a good dispersing effect on polar pigments and fillers such as titanium dioxide, iron black, iron oxide red, calcium carbonate, talc, and barium sulfate; urea groups have a good dispersing effect on non-polar pigment systems such as phthalocyanine blue and permanent red. The steric hindrance effect or the double-layer principle of the dispersant molecular chain segment is utilized to prevent pigment aggregation. The steric hindrance effect utilizes special groups in the dispersant, such as long-chain aliphatic hydrocarbons, which adsorb onto the surface of pigment particles, causing the pigment particles to slide and stagger, thereby achieving the steric hindrance effect to prevent pigment particle aggregation. The double-layer principle utilizes the fact that the dispersant itself carries a negative or positive charge. When the dispersant molecular chain segments are adsorbed onto the surface of pigment particles, the surface of the pigment particles will carry a charge. When two pigment particles with the same charge approach each other, the like charges will have an electrostatic repulsion effect, thereby preventing the pigment particles from agglomerating.

[0003] The preparation methods of dispersants in existing patents generally fall into the following three categories: (1) Physical mixing preparation process: Dispersing agents are prepared by physical heating and stirring dispersion with dispersing properties. For example, the patent "A high-performance environmentally friendly rubber dispersant" CN201710842191.X uses plant-based soybean oil oleic acid, sodium dodecyl sulfate, higher alcohol, erucic acid, and microcrystalline wax to finally prepare a dispersant for rubber after heating to 60-120℃. The advantage of this process is that it is simple and practical and has low requirements for equipment and process. The disadvantage is that the molecular weight of the dispersant is low, which affects the final dispersion effect. (2) Solution free radical polymerization preparation process: Oleic acid and other acrylic monomers are polymerized in a homogeneous solvent. For example, the patent "An oleic acid copolymer dispersion resin and its preparation method and application" CN202011568595.2 uses oleic acid, acrylic monomer and initiator to heat and free radical polymerize in a solvent to obtain an acrylic ester dispersant. The advantage of this process is that it produces polymer dispersants with larger molecular weights, which have better coating properties for pigments and better dispersing effect of the dispersing resin on pigments. The disadvantage is how to solve the problem of low double bond activity of oleic acid and large difference in the polymerization rate with other acrylic monomers during the free radical polymerization of oleic acid substances. (3) Esterification reaction process of oleic acid substances: some oleic acid substances contain both hydroxyl and carboxyl groups and react with other hydroxyl-containing substances in a polyester reaction. For example, in the patent "Polyester Dispersant" CN00813026.4, ricinoleic acid is esterified with caprolactone to prepare a polyester type dispersant. This process avoids the drawbacks of low double bond activity and incomplete reaction in oleic acid free radical polymerization. However, the drawback is that only some oleic acid substances contain both hydroxyl and carboxyl functional groups in one molecular chain segment, such as castor oil, which is more expensive than ordinary oleic acid. Most other oleic acids only contain carboxyl functional groups. If only the carboxyl group is used to react with the hydroxyl groups of other non-oleic acid substances in polyester, it will lead to a reduction in the carboxyl content of the final product and a decrease in the dispersing function, thus affecting the promotion and application of oleic acid polyester synthesis process. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a urea-based dispersant, its preparation method and application.

[0005] The technical solution adopted in this invention is as follows:

[0006] A urea-based dispersant, characterized in that it comprises the following two components by weight: 50-70 parts of a urea-based polymer and 30-50 parts of a diluent; wherein the urea-based polymer is prepared by chemical reaction of the following components by weight: 37.3-52.8 parts of isocyanate biuret or trimer, 11.8-26.4 parts of n-decylamine, and 25.0-44.8 parts of ricinoleic acid; the isocyanate biuret or trimer is selected from at least one of isocyanate biuret and isocyanate trimer; each molecular segment of the isocyanate biuret or trimer contains n -NCO groups, wherein n is 2 or 3, or any value selected from 2-3.

[0007] In one embodiment, the diluting solvent is at least one of benzene, ester, ether, and ketone solvents.

[0008] In one embodiment, the diluent is at least 30% to 50% of any one of benzene, ester, ether, or ketone solvents, in order to reduce viscosity for ease of use.

[0009] In one embodiment, the isocyanate biuret or trimer is selected from at least one of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), toluene diisocyanate (TDI), and diphenylmethane diisocyanate (MDI) biuret or trimer.

[0010] The structural formula of HDI trimer is as follows:

[0011]

[0012] In one specific embodiment, the isocyanate biuret or trimer is selected from at least one of isocyanate biuret and isocyanate trimer; each molecular segment of the isocyanate biuret or trimer contains n -NCO groups, where n is 2 or 3, or any value selected from 2 to 3. In one specific embodiment, the isocyanate biuret or trimer can be an isocyanate biuret or trimer, or a mixture of a difunctional isocyanate and a trifunctional isocyanate, that is, a mixture of isocyanate biuret and isocyanate trimer, such that the actual functionality is between 2 and 3, such as n being 2.3, 2.4, etc., therefore n can also be any value between 2 and 3.

[0013] The preparation method of the urea-based dispersant includes the following steps:

[0014] 1) The ricinoleic acid was heated to 100℃~125℃ and then subjected to vacuum dehydration;

[0015] 2) Cool the product after vacuum dehydration in step 1) to 50℃~60℃, purge with nitrogen, add isocyanate biuret or trimer in one go, then heat to 70℃~90℃ and keep warm for 2~3h;

[0016] 3) Dilute the product after heat preservation treatment in step 2) with solvent and cool it to 0℃~10℃. Add a solution containing n-decylamine dropwise. After the addition is complete, keep it at 0℃~30℃ for 1~3h to obtain the product.

[0017] In one embodiment, the order of steps 1), 2), and 3) can be replaced as follows: first, add isocyanate biuret or trimer and solvent all at once, then cool to 0°C to 10°C, purge with nitrogen, add a solution containing n-decylamine dropwise, and keep warm at 0°C to 30°C for 1 to 3 hours after the addition is complete; then add ricinoleic acid that has been pre-vacuum dehydrated, heat to 70°C to 90°C, and keep warm for 2 to 3 hours to obtain the final product.

[0018] In one embodiment, the urea polymer molecular chain segment contains three groups: carboxyl, urea, and aliphatic long carbon chain, and also contains a carboxylate anion: -COO―.

[0019] A method for preparing a urea-based dispersant includes the following steps:

[0020] 1) The ricinoleic acid was heated to 100℃~125℃ and then subjected to vacuum dehydration;

[0021] 2) Cool the product after vacuum dehydration in step 1) to 50℃~60℃, purge with nitrogen, add isocyanate biuret or trimer in one go, then heat to 70℃~90℃ and hold for 2~3h. The isocyanate biuret or trimer is selected from at least one of isocyanate biuret and isocyanate trimer. Each molecular chain segment of the isocyanate biuret or trimer contains n -NCO groups, where n is 2 or 3, or any value between 2 and 3.

[0022] 3) Dilute the product after heat preservation treatment in step 2) with solvent and cool it to 0℃~10℃. Add a solution containing n-decylamine dropwise. After the addition is complete, keep it at 0℃~30℃ for 1~3h to obtain the product.

[0023] In one embodiment, the order of steps 1), 2), and 3) can be replaced as follows: first, add isocyanate biuret or trimer and solvent all at once, then cool to 0°C to 10°C, purge with nitrogen, add a solution containing n-decylamine dropwise, and keep warm at 0°C to 30°C for 1 to 3 hours after the addition is complete; then add ricinoleic acid that has been pre-vacuum dehydrated, heat to 70°C to 90°C, and keep warm for 2 to 3 hours to obtain the final product.

[0024] In one embodiment, the vacuum dehydration process involves vacuum dehydration for 1 to 3 hours, with a vacuum degree of 0.08 to 1.0 MPa.

[0025] In one embodiment, the preparation method includes the following two-step reaction: First, an addition reaction is performed between isocyanate biuret or trimer and ricinoleic acid, wherein the isocyanate biuret or trimer is selected from at least one of isocyanate biuret and isocyanate trimer; each molecular segment of the isocyanate biuret or trimer contains n -NCO groups, where n is 2 or 3, or any value selected between 2 and 3, wherein some y -NCO groups react with the -OH group of ricinoleic acid to form a carbamate structure, wherein y is 1 or 2, or any value selected between 1 and 2; Second, the remaining ny -NCO groups in the isocyanate biuret or trimer react with the primary amino group -NH2 in n-decylamine at low temperature, wherein the second step introduces the functional group urea into the polymer, and further introduces an aliphatic long carbon chain, while some -COOH and secondary amino groups are neutralized and ionized.

[0026] The present invention also provides the application of the urea-based dispersant as a dispersing aid for organic pigments, inorganic pigments and fillers in coatings, rubber, plastics and the like.

[0027] This invention utilizes the chemical reaction of isocyanate with the hydroxyl group in ricinoleic acid and the amino group in n-decylamine at low temperature to prepare a polymer molecular chain segment containing three special groups: carboxyl group (-COOH), urea group (R-NH-CO-NH-R′), and aliphatic long carbon chain, as well as a carboxylate anion (-COO). ― The carboxyl group has a good dispersing effect on inorganic pigments, the urea group has a good dispersing effect on organic pigments, the aliphatic long carbon chain has a good coating effect on pigment particles, and the carboxylate anion has a good electrostatic repulsion effect on pigment particles. Therefore, this dispersant has a good dispersing effect on both organic and inorganic pigments, and can prevent pigment systems from having problems such as sedimentation, coarsening, thickening, and floating color. It is particularly suitable for complex mixed color paste systems of organic pigments, inorganic pigments and fillers.

[0028] The structure of ricinoleic acid is as follows:

[0029]

[0030] The ricinoleic acid molecular chain contains both carboxyl and hydroxyl groups. The hydroxyl groups react with isocyanate groups to form urethane, while the carboxyl groups are retained. At the same time, the ricinoleic acid molecular chain contains aliphatic long carbon chains. The carboxyl groups and aliphatic long carbon chains play a key role as functional groups of the polymer in dispersing inorganic pigments and fillers.

[0031] The structural formula of n-decylamine is as follows:

[0032]

[0033] Because the n-decylamine molecule contains aliphatic long carbon chains, the reactivity of the active hydrogen in the primary amine group is greatly reduced, allowing the primary amine in the n-decylamine molecule to react stably with the isocyanate group in the 0–10 °C range. If aliphatic carbon chains such as n-butylamine, n-hexylamine, and n-heptylamine are used, the reaction with isocyanate is too rapid, easily leading to polymer gelation; dodecylamine, with its even longer aliphatic carbon chains, is a crystalline substance at room temperature, resulting in polymers with excessively high viscosity that are difficult to apply. Therefore, n-decylamine is the preferred choice to meet the requirements.

[0034] The specific beneficial effects of this invention are as follows:

[0035] (1) The main component of the urea-based dispersant is a polymer with a number average molecular weight of 500 to 1200, which overcomes the defect of poor dispersion stability caused by the small molecular weight (number average molecular weight of 200 to 400) of traditional physical mixing preparation dispersants.

[0036] (2) The urea-based dispersant is prepared by the addition reaction of isocyanate-NCO with hydroxyl-OH and amino-NH2 at a lower temperature. This overcomes the molecular defects of oleic acid substances in traditional free radical polymerized acrylate dispersants, which have low double bond activity and are difficult to copolymerize uniformly, thus ensuring the stability of molecular structure and dispersion performance.

[0037] (3) Urea-based dispersants utilize the reaction between the hydroxyl group -OH and the isocyanate group -NCO in ricinoleic acid during the synthesis process, without reducing the number of carboxyl groups in ricinoleic acid that play an important dispersing role. Therefore, the dispersing effect of urea-based dispersants is stronger than that of ordinary polyester dispersants. Attached Figure Description

[0038] Figure 1 The reaction equation for HDI trimer A, ricinoleic acid B, and n-decylamine D;

[0039] Figure 2a The structural formula of HDI trimer A;

[0040] Figure 2b The structural formula of ricinoleic acid B;

[0041] Figure 2c for Figure 1 The structural formula of prepolymer C in the reaction formula;

[0042] Figure 2d The structural formula of n-decylamine D is given.

[0043] Figure 2e for Figure 1 The structural formula of the unionized dispersant E in the reaction formula;

[0044] Figure 2f for Figure 1 The structural formula of the ionized dispersant F in the reaction formula;

[0045] Figure 3 This is a schematic diagram of the functional groups in the molecular chain segment of a urea-based dispersant. Detailed Implementation

[0046] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0047] This invention relates to a urea-based dispersant, comprising 50%–70% urea-based polymer and 30%–50% diluent. The urea-based polymer is obtained by chemically polymerizing 37.3%–52.8% isocyanate biuret or trimer, 11.8%–26.4% n-decylamine, and 25%–44.8% ricinoleic acid. The diluent is 30%–70% of one or more benzene, ester, ether, or ketone solvents, used to reduce viscosity for ease of use. All percentages mentioned in this paragraph are by mass.

[0048] In one embodiment, the diluting solvent is at least one of benzene, ester, ether, and ketone solvents.

[0049] In one embodiment, the diluent is at least 30% to 50% of any one of benzene, ester, ether, or ketone solvents, in order to reduce viscosity for ease of use.

[0050] In one embodiment, the isocyanate biuret or trimer is selected from at least one of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), toluene diisocyanate (TDI), and diphenylmethane diisocyanate (MDI) biuret or trimer.

[0051] The structural formula of HDI trimer is as follows:

[0052]

[0053] In one specific embodiment, the isocyanate biuret or trimer is selected from at least one of isocyanate biuret and isocyanate trimer; each molecular segment of the isocyanate biuret or trimer contains n -NCO groups, where n is 2 or 3, or any value selected from 2 to 3. In one specific embodiment, the isocyanate biuret or trimer can be an isocyanate biuret or trimer, or a mixture of a difunctional isocyanate and a trifunctional isocyanate, that is, a mixture of isocyanate biuret and isocyanate trimer, such that the actual functionality is between 2 and 3, such as n being 2.3, 2.4, etc., therefore n can also be any value between 2 and 3.

[0054] The preparation method of the urea-based dispersant includes the following steps:

[0055] 1) The ricinoleic acid was heated to 100℃~125℃ and then subjected to vacuum dehydration;

[0056] 2) Cool the product after vacuum dehydration in step 1) to 50℃~60℃, purge with nitrogen, add isocyanate biuret or trimer in one go, then heat to 70℃~90℃ and keep warm for 2~3h;

[0057] 3) Dilute the product after heat preservation treatment in step 2) with solvent and cool it to 0℃~10℃. Add a solution containing n-decylamine dropwise. After the addition is complete, keep it at 0℃~30℃ for 1~3h to obtain the product.

[0058] In one embodiment, the order of steps 1), 2), and 3) can be replaced as follows: first, add isocyanate biuret or trimer and solvent all at once, then cool to 0°C to 10°C, purge with nitrogen, add a solution containing n-decylamine dropwise, and keep warm at 0°C to 30°C for 1 to 3 hours after the addition is complete; then add ricinoleic acid that has been pre-vacuum dehydrated, heat to 70°C to 90°C, and keep warm for 2 to 3 hours to obtain the final product.

[0059] In one embodiment, the urea polymer molecular chain segment contains three groups: carboxyl, urea, and aliphatic long carbon chain, and also contains a carboxylate anion: -COO ― .

[0060] A method for preparing a urea-based dispersant includes the following steps:

[0061] 1) The ricinoleic acid was heated to 100℃~125℃ and then subjected to vacuum dehydration;

[0062] 2) Cool the product after vacuum dehydration in step 1) to 50℃~60℃, purge with nitrogen, add isocyanate biuret or trimer in one go, then heat to 70℃~90℃ and hold for 2~3h. The isocyanate biuret or trimer is selected from at least one of isocyanate biuret and isocyanate trimer. Each molecular chain segment of the isocyanate biuret or trimer contains n -NCO groups, where n is 2 or 3, or any value between 2 and 3.

[0063] 3) Dilute the product after heat preservation treatment in step 2) with solvent and cool it to 0℃~10℃. Add a solution containing n-decylamine dropwise. After the addition is complete, keep it at 0℃~30℃ for 1~3h to obtain the product.

[0064] In one embodiment, the order of steps 1), 2), and 3) can be replaced as follows: first, add isocyanate biuret or trimer and solvent all at once, then cool to 0°C to 10°C, purge with nitrogen, add a solution containing n-decylamine dropwise, and keep warm at 0°C to 30°C for 1 to 3 hours after the addition is complete; then add ricinoleic acid that has been pre-vacuum dehydrated, heat to 70°C to 90°C, and keep warm for 2 to 3 hours to obtain the final product.

[0065] In one embodiment, the vacuum dehydration process involves vacuum dehydration for 1 to 3 hours, with a vacuum degree of 0.08 to 1.0 MPa.

[0066] In one embodiment, the preparation method includes the following two-step reaction: First, an addition reaction is performed between isocyanate biuret or trimer and ricinoleic acid, wherein the isocyanate biuret or trimer is selected from at least one of isocyanate biuret and isocyanate trimer; each molecular segment of the isocyanate biuret or trimer contains n -NCO groups, where n is 2 or 3, or any value selected between 2 and 3, wherein some y -NCO groups react with the -OH group of ricinoleic acid to form a carbamate structure, wherein y is 1 or 2, or any value selected between 1 and 2; Second, the remaining ny -NCO groups in the isocyanate biuret or trimer react with the primary amino group -NH2 in n-decylamine at low temperature, wherein the second step introduces the functional group urea into the polymer, and further introduces an aliphatic long carbon chain, while some -COOH and secondary amino groups are neutralized and ionized.

[0067] The present invention also provides the application of the urea-based dispersant as a dispersing aid for organic pigments, inorganic pigments and fillers in coatings, rubber, plastics and the like.

[0068] Figure 1 This is an example of the synthetic reaction formula for the urea-based polymer involved in the present invention. Figure 2a The structural formula of HDI trimer A; Figure 2b The structural formula of ricinoleic acid B; Figure 2c for Figure 1 The structural formula of prepolymer C in the reaction formula; Figure 2d The structural formula of n-decylamine D is given. Figure 2e for Figure 1 The structural formula of the unionized dispersant E in the reaction formula; Figure 2f for Figure 1 The structural formula of the ionized dispersant F in the reaction formula.

[0069] Urea polymers are synthesized in two steps. The first step involves an addition reaction between HDI trimer A and ricinoleic acid B. In each molecular segment of the HDI trimer, one to two of the three -NCO groups react with the -OH group of ricinoleic acid to generate a prepolymer C containing urethane and some of the remaining isocyanate groups. This first step introduces the functional group -COOH and a special aliphatic long carbon chain segment into the polymer. The -COOH group has a good dispersion effect on inorganic pigments, especially metal oxides such as titanium dioxide, iron oxide black, iron oxide red, calcium carbonate, talc, and barium sulfate. At the same time, the aliphatic long carbon chain can stably coat the inorganic pigments and prevent the pigment particles from agglomerating. The second step involves the low-temperature addition reaction of the remaining 1-2 -NCO groups in prepolymer C with the primary amino group -NH2 in the n-decylamine D molecular chain segment to synthesize unionized dispersant E. This second step introduces the functional group urea into the polymer, and further introduces aliphatic long carbon chains. The urea group exhibits good dispersing effects on organic pigments, such as phthalocyanine blue, while the further introduced aliphatic long carbon chains can also fully coat the organic pigment particles. The secondary amino group (-NH-) and carboxyl group (-COOH) in the unionized dispersant E molecular chain segment undergo an ionization reaction to generate ionized dispersant F. The -COO group in the ionized dispersant F molecular chain segment... - The electrostatic repulsion effect after coating the pigment particles can further prevent pigment particle aggregation. It should be noted that the addition reaction and the ionization neutralization reaction in the second step described above are usually carried out simultaneously in reality due to their relatively fast reaction rates. The reaction equations in the patent are presented step-by-step to illustrate the theoretical mechanism of the chemical reaction; the structural formula of the final ionized dispersant F is consistent throughout.

[0070] Example 1

[0071] Preparation of urea-based dispersant FSJ-1

[0072] Add 30.9g of ricinoleic acid to a 250ml four-necked reaction flask and heat to 100℃. Dehydrate under vacuum for 2 hours at a vacuum degree of 0.09MPa. Cool to 50℃, continuously purge with nitrogen, and add 52.8g of N-75 at once. Slowly heat to 80℃ and hold for 3 hours. Cool to 0℃ and slowly add 103.1g of a mixed solution (containing 16.3g of n-decylamine, 66.8g of xylene, and 20g of diisobutyl ketone) dropwise over 3 hours. After the addition is complete, heat to 10℃ and hold for 3 hours before discharging. FSJ-1 has a solid content of 50%, is a light brown, transparent, viscous liquid with a viscosity of 3175mPa·s.

[0073] Example 2

[0074] Preparation of urea-based dispersant FSJ-2

[0075] Add 44.8g of ricinoleic acid to a 250ml four-necked reaction flask and heat to 110℃. Dehydrate under vacuum for 1.5h at a vacuum degree of 0.08MPa. Cool to 60℃, continuously purge with nitrogen, and add 43.4g of N3300 at once. Slowly heat to 90℃ and hold for 3h. Cool to 3℃ and slowly add 54.7g of a mixed solution (containing 11.8g of n-decylamine and 42.9g of diisobutyl ketone) dropwise over 3h. After the addition is complete, heat to 20℃ and hold for 3h before discharging. FSJ-2 has a solid content of 70%, is a dark brown, transparent, viscous liquid with a viscosity of 5290mPa·s.

[0076] Example 3

[0077] Preparation of urea-based dispersant FSJ-3

[0078] 25.0 g of ricinoleic acid was added to a 500 ml four-necked reaction flask and heated to 120 °C. The mixture was then dehydrated under vacuum for 1.5 h at a vacuum degree of 0.07 MPa. The temperature was lowered to 50 °C, and nitrogen gas was continuously purged. 48.6 g of N3300 was added in one go, and the temperature was slowly raised to 90 °C and held for 3 h. The temperature was then lowered to 0 °C, and 126.4 g of a mixed solution (containing 26.4 g of n-decylamine, 80 g of xylene, and 20 g of diisobutyl ketone) was slowly added dropwise over 6 h. After the addition was complete, the temperature was raised to 15 °C and held for 3 h before discharging. FSJ-3 has a solid content of 50%, is a light brown, transparent, viscous liquid, and has a viscosity of 5615 mPa·s.

[0079] Example 4

[0080] Preparation of urea-based dispersant FSJ-4

[0081] Add 41.1g of ricinoleic acid to a 250ml four-necked reaction flask and heat to 110℃. Dehydrate under vacuum for 2.5h at a vacuum degree of 0.08MPa. Cool to 60℃, continuously purge with nitrogen, and add 37.3g of PM200 at once. Slowly heat to 90℃ and hold for 3h. Cool to 3℃ and slowly add 121.6g of a mixed solution (containing 21.6g of n-decylamine, 60g of xylene, and 40g of diisobutyl ketone) dropwise over 3h. After the addition is complete, heat to 20℃ and hold for 3h before discharging. FSJ-4 has a solid content of 50%, is a dark brown, transparent, viscous liquid with a viscosity of 4910mPa·s.

[0082] Comparative Example 1

[0083] Preparation of urea-free dispersant FSJ-0

[0084] Add 60.7g of ricinoleic acid to a 250ml four-necked reaction flask and heat to 110℃. Dehydrate under vacuum for 3 hours at a vacuum degree of 0.08MPa. Cool to 60℃, continuously purge with nitrogen, add 39.3g of N3300 at once, slowly heat to 90℃ and hold for 3 hours. Add 70g of xylene and 30g of diisobutyl ketone, mix thoroughly, and then discharge. FSJ-0 has a solid content of 50%, is a dark brown, transparent, viscous liquid with a viscosity of 1475mPa·s.

[0085] In Example 1 above, N-75 is an HDI biuret curing agent from Bayer AG, Germany, with a solid content of 75% and an isocyanate content of 16.5%; in Examples 2 and 3, N3300 is an HDI trimer curing agent from Covestro, with a solid content of 100% and an isocyanate content of 21.8%; in Example 4, PM200 is a polymeric MDI from Yantai Wanhua Chemical, with a solid content of 100% and an isocyanate content of 31.2%.

[0086] In the above examples and comparative examples, the viscosity of FSJ-0 to FSJ-4 is rotational viscosity, which was determined at 25°C according to the national standard GB / T2794-2013; the solid content was determined by weighing 1.0g of sample and placing it in an oven at 160°C for 2h according to the national standard GB / T1725-2007.

[0087] Performance comparison:

[0088] The dispersant samples from the above examples and comparative examples were mixed with resin, pigments and fillers, and then ground in a sand mill at 2000 r / min for 4 h for performance testing. The formulation and performance results after testing are shown in Table 1 below.

[0089] Table 1 Comparison of applications between urea-based and non-urea-based dispersants.

[0090]

[0091]

[0092] Table 1 shows the grinding formulation. The 308 polyester resin is from Shandong Yili New Materials Co., Ltd., K7090 phthalocyanine blue is from BASF (Germany), 902 titanium dioxide is from DuPont (USA), and BSP-1 barium sulfate is ultrafine precipitated barium sulfate from Jiangsu Qunxin Powder Technology Co., Ltd. The amount of dispersant FSJ-2 is 2.86g, and the other dispersants are all 4g. This is because FSJ-2 has a solid content of 70%, while the other dispersants have a solid content of 50%. To ensure that the solid content of each dispersant (excluding the solvent) is 2g, a parallel control experiment can be conducted.

[0093] The viscosity used in the performance test is rotational viscosity, which is measured at 20℃ according to the national standard GB / T 2794-2013; fineness is tested according to the national standard GB / T6753.1-2007; and appearance and color difference are tested according to the national standard GB / T 5211.20-1999.

[0094] Table 1 selects three representative pigments and fillers: organic pigment phthalocyanine blue, inorganic pigment titanium dioxide, and inorganic filler barium sulfate, forming a relatively complex mixed color paste system to facilitate the evaluation of the overall dispersion effect of the dispersant on different types of pigments and fillers. As can be seen from Table 1, under relatively small dosage conditions, the viscosity of the color pastes in Examples FSJ-1, -2, -3, and -4, except for formulation group #3 of FSJ-3, is within a small range of 1000–1500 mPa·s, indicating relatively stable viscosity. The viscosity of color paste #3 is slightly higher because the FSJ-3 molecular chain segment added to #3 contains a higher content of urea groups. On the one hand, this provides better dispersion of the organic pigment; on the other hand, the urea groups increase the viscosity of the color paste system. As can be seen from the comparison of the fineness of the color pastes in Table 1, the fineness of the color pastes in the examples is all below 15 μm, while the fineness of the color pastes in the comparative examples is 25 μm. Furthermore, after standing for 48 hours, no sedimentation or floating color phenomenon was observed in the examples, and the color difference ΔE was all between 0.1 and 0.2. This indicates that the urea-based dispersant in the examples has a good dispersing effect on the mixed color paste system, and the pigment particles did not agglomerate or settle after standing, indicating that the examples have a good dispersion and coating effect on the mixed pigment and filler system. In contrast, the color paste prepared in the comparative example without the urea-based dispersant FSJ-0 showed obvious blue floating after standing for 48 hours, and the color difference ΔE was higher, indicating that the urea-free dispersant did not effectively disperse and coat phthalocyanine blue.

[0095] For those skilled in the art, various other corresponding changes and modifications can be made based on the technical solutions and concepts described above, and all such changes and modifications should fall within the protection scope of the claims of this invention.

Claims

1. A urea-based dispersant, characterized in that, The product comprises the following two components by weight: 50-70 parts of urea-based polymer and 30-50 parts of diluent solvent; the urea-based polymer is prepared by chemical reaction of the following components by weight: 37.3-52.8 parts of isocyanate biuret or trimer, 11.8-26.4 parts of n-decylamine, and 25.0-44.8 parts of castor oil acid; the isocyanate biuret or trimer is selected from at least one type of isocyanate biuret or at least one type of isocyanate trimer; each molecular segment of the isocyanate biuret or trimer contains n -NCO groups, where n is 2 or 3; the molecular segment of the urea-based polymer contains three groups: carboxyl, urea, and aliphatic long carbon chain, and also contains a carboxylate anion: -COO. ― .

2. The urea-based dispersant as described in claim 1, characterized in that, The diluting solvent is at least one of benzene, ester, ether, and ketone solvents.

3. The urea-based dispersant as described in claim 1 or 2, characterized in that, The isocyanate biuret or trimer is selected from at least one biuret or at least one trimer of hexamethylene diisocyanate, isophorone diisocyanate, toluene diisocyanate, and diphenylmethane diisocyanate.

4. The urea-based dispersant as described in claim 1, characterized in that, The preparation method of the urea-based dispersant includes the following steps: 1) The ricinoleic acid is heated to 100℃~125℃ and then subjected to vacuum dehydration; 2) Cool the product after vacuum dehydration in step 1) to 50℃~60℃, purge with nitrogen, add isocyanate biuret or trimer in one go, then heat to 70℃~90℃ and keep warm for 2~3 hours; 3) Dilute the product after heat preservation treatment in step 2) with solvent and cool it to 0℃~10℃. Add a solution containing n-decylamine dropwise. After the addition is complete, keep it at 0℃~30℃ for 1~3h to obtain the product.

5. The urea-based dispersant according to claim 4, characterized in that, The order of steps 1), 2), and 3) can be replaced as follows: First, add the isocyanate biuret or trimer and solvent all at once, then cool to 0℃~10℃, purge with nitrogen, add a solution containing n-decylamine dropwise, and keep warm at 0℃~30℃ for 1~3 hours after the addition is complete; then add ricinoleic acid that has been pre-vacuum dehydrated, heat to 70℃~90℃, and keep warm for 2~3 hours to obtain the final product.

6. A method for preparing a urea-based dispersant as described in claim 1 or claim 2, comprising the following steps: 1) The ricinoleic acid is heated to 100℃~125℃ and then subjected to vacuum dehydration; 2) Cool the product after vacuum dehydration in step 1) to 50℃~60℃, purge with nitrogen, add isocyanate biuret or trimer in one go, then heat to 70℃~90℃ and hold for 2~3 hours. The isocyanate biuret or trimer is selected from at least one type of isocyanate biuret or at least one type of isocyanate trimer. Each molecular chain segment of the isocyanate biuret or trimer contains n -NCO groups, where n is 2 or 3. 3) Dilute the product after heat preservation treatment in step 2) with solvent and cool it to 0℃~10℃. Add a solution containing n-decylamine dropwise. After the addition is complete, keep it at 0℃~30℃ for 1~3h to obtain the product.

7. The method for preparing the urea-based dispersant as described in claim 6, characterized in that, The order of steps 1), 2), and 3) can be replaced as follows: First, add the isocyanate biuret or trimer and solvent all at once, then cool to 0℃~10℃, purge with nitrogen, add a solution containing n-decylamine dropwise, and keep warm at 0℃~30℃ for 1~3 hours after the addition is complete; then add ricinoleic acid that has been pre-vacuum dehydrated, heat to 70℃~90℃, and keep warm for 2~3 hours to obtain the final product.

8. The urea-based dispersant according to any one of claims 1 to 5 or the urea-based dispersant obtained by any one of claims 6 to 7 is used as a dispersing aid for organic pigments, inorganic pigments and fillers in coatings, rubber and plastics.

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