Waterborne polyurethane thickening agent with good fluidity and preparation method thereof

Abstract

The invention provides a waterborne polyurethane thickening agent with good fluidity and a preparation method thereof, and belongs to the technical field of thickening agents. The waterborne polyurethane thickening agent disclosed by the invention is prepared from the following raw materials in parts by mass: 200 to 500 parts of polyether type diol, 0.05 to 0.1 part of a catalyst, 15 to 20 parts of isocyanate, 0.5 to 1 part of a chain extender A, 0.05 to 0.1 part of a chain extender B, 15 to 20 parts of an end-capping reagent, 90 to 110 parts of a solvent and 200 to 280 parts of water. By adopting the compounded chain extender, the chain length of polyurethane can be prolonged, the surface tension of polyurethane can be reduced, and the fluidity of the thickening agent can be improved, so that the thickening agent not only has good fluidity, but also can enhance the thickening effect of the thickening agent.

Description

Technical Field

[0001] The present invention relates to the technical field of thickeners, and particularly relates to an aqueous polyurethane thickener with good fluidity and a preparation method thereof. Background Art

[0002] With the development of society and the progress of technology, in order to increase the viscosity, adhesion and other properties of products, thickeners are more and more commonly used in life. At present, there are many types of thickeners on the market, and they have different thickening principles according to different systems. Polyurethane thickeners are a relatively commonly used type of polymer thickeners, which are widely used in the fields of resins, coatings, floors, etc. However, in the field of coating applications, due to the relatively high molecular weight of aqueous polyurethane thickeners and the good thickening effect of the prepared thickeners on water itself, the prepared aqueous polyurethane thickeners have high viscosity and poor fluidity, and poor thickening dispersibility in the coating field. Based on the existence of the above problems, the present invention prepares an aqueous polyurethane thickener with good fluidity to solve the problems of high viscosity, poor fluidity and poor thickening dispersibility in the coating field of the thickener itself. Summary of the Invention

[0003] The purpose of the present invention is to provide an aqueous polyurethane thickener with good fluidity and a preparation method thereof, which are used to solve the technical problems of high viscosity, poor fluidity and poor thickening dispersibility in the coating field of the existing thickeners.

[0004] In order to achieve the above invention purpose, the present invention provides the following technical solutions:

[0005] The present invention provides an aqueous polyurethane thickener with good fluidity, which is prepared from raw materials comprising the following mass parts:

[0006]

[0007]

[0008] The chain extender A is a glycerol ester, and the chain extender B is a polydimethylsiloxane capped with an active hydroxyl group.

[0009] Further, the polyether diol is polyether polyethylene glycol, and the average molecular weight of the polyether polyethylene glycol is 2000 - 10000 Da;

[0010] The isocyanate is a diisocyanate, and the diisocyanate includes one or more of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate and dicyclohexyl diisocyanate.

[0011] Further, the glycerides include one or more of glycerol monooleate, triglyceryl monolaurate, and glyceryl triethylhexanoate;

[0012] The poly(dimethylsiloxane) capped with an active hydroxyl group contains aminoalkyl-terminated poly(dimethylsiloxane) and / or hydroxyalkyl-terminated poly(dimethylsiloxane).

[0013] Further, the raw materials further contain an emulsifier, and the dosage of the emulsifier is 2-10% of the mass fraction of the thickener system.

[0014] Further, the capping agent is an alkanol, and the alkanol contains one or more of dodecanol, tetradecanol, hexadecanol, and octadecanol;

[0015] The catalyst contains an organometallic catalyst, and the solvent contains an alcohol ether solvent.

[0016] The present invention also provides a preparation method of an aqueous polyurethane thickener with good fluidity, comprising the following steps:

[0017] 1) Purify the polyether-based diol;

[0018] 2) Add the catalyst and isocyanate to the purified polyether-based diol, and react under the protection of an inert gas to obtain a reaction product;

[0019] 3) Sequentially add chain extender A, chain extender B, and capping agent to the reaction product for reaction, cool down, and then add the remaining raw materials to obtain an aqueous polyurethane thickener with good fluidity.

[0020] Further, the purification treatment is to heat the polyether-based diol to 110-130 °C and evacuate for 3-4 h.

[0021] Further, in step 2), the reaction temperature is 60-80 °C and the reaction time is 2-4 h.

[0022] Further, the reaction temperature for adding chain extender A and chain extender B to the reaction product is 90-120 °C and the time is 2-3 h;

[0023] The reaction temperature for adding the capping agent to the reaction product is 110-130 °C and the time is 4-6 h.

[0024] Further, the temperature for cooling down is 70-100 °C.

[0025] The beneficial effects of the present invention:

[0026] (1) The aqueous polyurethane thickener of the present invention uses polyethylene glycol with an average molecular weight of 6000, and forms a crosslinked network of polyurethane with a weight ratio of (200-300):(15-20) to the diisocyanate, achieving a thickening effect.

[0027] (2) The present invention uses a composite chain extender of triglycerol monolaurate and poly(dimethylsiloxane) (600) capped with hydroxyalkyl groups, which can extend the chain length of the polyurethane, reduce the surface tension of the polyurethane, and improve the fluidity of the thickener. The possible reasons are as follows: both glycerol esters and poly(dimethylsiloxane) chain extenders capped with active hydroxyalkyl groups have relatively low surface tensions and good fluidities, and have better synergistic effects with each other. In addition, glycerol esters have strong hydrophilicity and a large hydrogen bond effect on water, so they not only have good fluidity but also can enhance the thickening effect of the thickener. Specific embodiments

[0028] The present invention provides an aqueous polyurethane thickener with good fluidity, which is prepared from raw materials comprising the following parts by mass:

[0029]

[0030] The chain extender A is a glycerol ester, and the chain extender B is a poly(dimethylsiloxane) capped with an active hydroxy group.

[0031] In the present invention, calculated by parts by mass, the dosage of the polyether diol is preferably 300-400 parts, and more preferably 320-380 parts.

[0032] In the present invention, calculated by parts by mass, the dosage of the catalyst is preferably 0.06-0.08 parts, and more preferably 0.07 parts.

[0033] In the present invention, calculated by parts by mass, the dosage of the isocyanate is preferably 16-19 parts, and more preferably 17-18 parts.

[0034] In the present invention, calculated by parts by mass, the dosage of the chain extender A is preferably 0.6-0.9 parts, and more preferably 0.7-0.8 parts.

[0035] In the present invention, calculated by parts by mass, the dosage of the chain extender B is preferably 0.06-0.09 parts, and more preferably 0.07-0.08 parts.

[0036] In the present invention, calculated by parts by mass, the dosage of the capping agent is preferably 16-19 parts, and more preferably 17-18 parts.

[0037] In the present invention, by mass parts, the dosage of the solvent is preferably 95 to 105 parts, more preferably 100 parts.

[0038] In the present invention, by mass parts, the dosage of the water is preferably 220 to 260 parts, more preferably 240 to 250 parts.

[0039] In the present invention, the chain extender A is glycerol esters, and the glycerol esters are preferably one or more of glycerol monooleate, triglycerol monolaurate, and glycerol triethylhexanoate, more preferably triglycerol monolaurate.

[0040] In the present invention, the chain extender B is a polydimethylsiloxane capped with an active hydroxyl group, preferably an aminoalkyl-capped polydimethylsiloxane and / or a hydroxyalkyl-capped polydimethylsiloxane, more preferably an aminoalkyl-capped polydimethylsiloxane (300), a hydroxyalkyl-capped polydimethylsiloxane (600), a hydroxyalkyl-capped polydimethylsiloxane (1000), or a hydroxyalkyl-capped polydimethylsiloxane (2000).

[0041] In the present invention, the polyether diol is polyether polyethylene glycol, and the average molecular weight of the polyether polyethylene glycol is 2000 to 10000 Da, preferably PEG2000, PEG4000, PEG6000, PEG8000, PEG10000.

[0042] In the present invention, the isocyanate is a diisocyanate, and the diisocyanate includes one or more of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, and dicyclohexyl diisocyanate, preferably isophorone diisocyanate.

[0043] In the present invention, the raw materials further include an emulsifier, and the dosage of the emulsifier is 2 to 10% of the mass fraction of the thickener system, preferably 4 to 8%, more preferably 6 to 7%.

[0044] In the present invention, the emulsifier is a non-ionic surfactant, preferably isoparaffin alcohol polyoxyethylene ether, more preferably isomeric alcohol polyoxyethylene ether, and even more preferably isomeric octanol polyoxyethylene ether, isomeric nonanol polyoxyethylene ether, isomeric decanol polyoxyethylene ether, isomeric undecanol polyoxyethylene ether, isomeric tridecanol polyoxyethylene ether, isomeric tetradecanol polyoxyethylene ether.

[0045] In the present invention, the capping agent is an alkanol, and the alkanol includes one or more of dodecanol, tetradecanol, hexadecanol, and octadecanol, preferably dodecanol.

[0046] In the present invention, the catalyst comprises an organometallic catalyst, preferably bismuth organic carboxylate; the solvent comprises an alcohol ether solvent, more preferably butyl ether.

[0047] The present invention also provides a method for preparing a waterborne polyurethane thickener with good fluidity, comprising the following steps:

[0048] 1) Purify the polyether diol;

[0049] 2) Add the catalyst and isocyanate to the purified polyether diol, and react under the protection of an inert gas to obtain a reaction product;

[0050] 3) Sequentially add chain extender A, chain extender B, and capping agent to the reaction product for reaction, cool down, and then add the remaining raw materials to obtain a waterborne polyurethane thickener with good fluidity.

[0051] In the present invention, the purification treatment is to heat the polyether diol to 110 - 130 °C, preferably 120 °C; evacuate for 3 - 4 h, preferably 3.5 h.

[0052] In the present invention, in step 2), the reaction temperature is 60 - 80 °C, preferably 65 - 75 °C, more preferably 70 °C; the reaction time is 2 - 4 h, preferably 3 h.

[0053] In the present invention, the reaction temperature for adding chain extender A and chain extender B to the reaction product is 90 - 120 °C, preferably 100 - 110 °C; the time is 2 - 3 h, preferably 2.5 h.

[0054] In the present invention, the reaction temperature for adding the capping agent to the reaction product is 110 - 130 °C, preferably 120 °C; the time is 4 - 6 h, preferably 5 h.

[0055] In the present invention, the temperature for cooling down is 70 - 100 °C, preferably 80 - 90 °C, more preferably 85 °C.

[0056] In the present invention, in step 3), the remaining raw materials comprise an emulsifier. The specific operation of adding the remaining raw materials is as follows: cool down to 80 °C, add the solvent, and hold for 0.5 h; then cool down to 70 °C, add the emulsifier and water, stir for 1 - 1.5 h, and then add the remaining water and stir for 4 h.

[0057] In the present invention, the applicant found during the experiment that by using PEG6000 and isophorone diisocyanate jointly and adopting a mass ratio of (200 - 300):(15 - 20), a polyurethane thickener with good thickening effect can be obtained. The possible reason is that when PEG6000 and isophorone diisocyanate act jointly, the resulting polyurethane has a dense crosslinked network and can be used as a thickener. The high molecular weight polyglycol has a rich branched chain structure, which can facilitate the formation of the crosslinked structure of the crosslinked network. However, when the weight ratio of PEG6000 to diisocyanate is (200 - 300):(15 - 20), the isophorone diisocyanate is in excess, and the formed thickener is unstable and prone to delamination when applied to the thickening system, destroying the overall stability of the system.

[0058] In the present invention, the applicant found during the experiment that by using polyglycerol monolaurate and a composite chain extender of hydroxyalkyl-terminated polydimethylsiloxane (600), the chain length of the polyurethane can be extended, the surface tension of the polyurethane can be reduced, and the fluidity of the thickener can be improved. The possible reason is that both glycerol esters and the chain extender of hydroxyalkyl-terminated polydimethylsiloxane have relatively low surface tension and good fluidity, and have better synergistic effects with each other. In addition, glycerol esters have strong hydrophilicity and a large hydrogen bond effect on water, so they not only have good fluidity but also can enhance the thickening effect of the thickener.

[0059] The technical solutions provided by the present invention will be described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0060] Example 1

[0061] An aqueous polyurethane thickener is prepared from raw materials containing the following mass fractions:

[0062] 300 parts of polyester-type diol, 0.07 part of organic carboxylic acid bismuth catalyst, 18 parts of isocyanate, 0.8 part of chain extender A, 0.08 part of chain extender B, 18 parts of capping agent, 15 parts of emulsifier, 100 parts of solvent, and 250 parts of water.

[0063] The polyether-type diol is PEG6000, purchased from Hai'an Petrochemical Factory, Jiangsu Province.

[0064] The isocyanate is isophorone diisocyanate.

[0065] The chain extender is a combination of glycerol monooleate and aminoalkyl-terminated polydimethylsiloxane (300), and the weight ratio is 10:1.

[0066] The capping agent is cetyl alcohol, the emulsifier is isomeric tridecyl alcohol polyoxyethylene ether, and the solvent is butyl ether.

[0067] A preparation method of an aqueous polyurethane thickener, comprising the following steps:

[0068] S1: Purify the polyether diol, heat it to 120 °C, and evacuate for 4 h;

[0069] S2: Add bismuth organic carboxylate catalyst and isocyanate to the purified polyether diol under heating, introduce inert gas N 2 , stir under inert gas protection, heat up to 65 °C, and react for 2 h;

[0070] S3: Then add chain extender A and chain extender B, continuously heat up to 100 °C, and react for 2 h;

[0071] S4: Then add a capping agent, continuously keep the temperature at 110 °C, and react for 5 h;

[0072] S5: Cool down to 80 °C, add a solvent, and keep for 0.5 h; then cool down to 70 °C, add an emulsifier and water, stir for 1.5 h, and then add the remaining water, and stir for 4 h.

[0073] Example 2

[0074] An aqueous polyurethane thickener and its preparation method, the specific steps are the same as those in Example 1, the difference is that the chain extender A is glycerol monooleate, and the chain extender B is aminoalkyl-terminated polydimethylsiloxane (600).

[0075] Example 3

[0076] An aqueous polyurethane thickener and its preparation method, the specific steps are the same as those in Example 1, the difference is that the chain extender A is glycerol monooleate, and the chain extender B is aminoalkyl-terminated polydimethylsiloxane (1000).

[0077] Example 4

[0078] An aqueous polyurethane thickener and its preparation method, the specific steps are the same as those in Example 1, the difference is that the chain extender A is glycerol monooleate, and the chain extender B is aminoalkyl-terminated polydimethylsiloxane (2000).

[0079] Comparative Example 1

[0080] An aqueous polyurethane thickener and its preparation method, the specific steps are the same as those in Example 1, the difference is that the chain extender is 1,4-butanediol, and the addition amount is 1 part.

[0081] Comparative Example 2

[0082] An aqueous polyurethane thickener and its preparation method, the specific steps are the same as those in Example 1, the difference is that the chain extender is 1,6-hexanediol, and the addition amount is 1.6 parts.

[0083] Performance Test

[0084] 1. Thickenning time and effect test: 1.6 g of the thickeners prepared in Examples 1 to 4 and Comparative Examples 1 to 2 were respectively taken and added to 200 g of an aqueous resin emulsion. The viscosity of the system was tested. The test results are shown in Table 1. The aqueous resin emulsion was purchased from Hongdeli New Materials Co., Ltd., and the model was H-380; the viscosity of the aqueous resin emulsion without a thickener was 163 mPa·s. The viscosity of the competing product thickener added was 4332 mPa·s, and the competing product was 50A.

[0085] 2. Fluidity test: 3 g of the thickened emulsion selected in Test 1 was dropped on a glass panel, and after standing upright, the flow rate was observed.

[0086] 3. Stability test: 100 g of the thickeners prepared in Examples 1 to 4 and Comparative Examples 1 to 2 were respectively placed in 200 mL reagent bottles and left standing for 90 days. The appearance of the thickeners was observed to judge the stability. The test results are shown in Table 1.

[0087] Table 1 Test Results

[0088] Viscosity / mPa.s Flowability Stability Example 1 18021 General No delamination and no precipitation Example 2 20875 Better No delamination and no precipitation Example 3 150374 Good No delamination and no precipitation Example 4 224211 Good No delamination and no precipitation Comparative Example 1 9577 Poor No delamination and no precipitation Comparative Example 2 10666 Poor No delamination and no precipitation

[0089] As can be seen from the above examples, the present invention provides an aqueous polyurethane thickener with good fluidity and a preparation method thereof. As can be seen from the above experimental tests, the thickener of the present invention has good fluidity, and will not undergo stratification and precipitation phenomena during long-term storage, and has good storage stability.

[0090] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A water-based polyurethane thickener with good fluidity, characterized in that: Prepared from the following raw materials in parts by weight: The chain extender A is a glycerate, and the chain extender B is a polydimethylsiloxane terminated with an active hydroxyl group.

2. The aqueous polyurethane thickener with good fluidity according to claim 1, characterized in that: The polyether diol is polyether polyethylene glycol, and the average molecular weight of the polyether polyethylene glycol is 2000-10000Da; The isocyanate is a diisocyanate, and the diisocyanate includes one or more of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate and dicyclohexyl diisocyanate.

3. The aqueous polyurethane thickener with good fluidity according to claim 1 or 2, characterized in that: The glycerides include one or more of glyceryl monooleate, triglycerol monolaurate and glyceryl triethylhexanoate; The reactive hydroxyl group-containing end-blocked polydimethylsiloxane comprises aminoalkyl end-blocked polydimethylsiloxane and / or hydroxyalkyl end-blocked polydimethylsiloxane.

4. The water-based polyurethane thickener with good fluidity according to claim 1, characterized in that: The raw materials also contain an emulsifier, and the amount of the emulsifier is 2-10% of the mass fraction of the thickener system.

5. The aqueous polyurethane thickener with good fluidity according to claim 1 or 4, characterized in that: The end-capping agent is an alkanol, and the alkanol includes one or more of dodecanol, tetradecanol, hexadecanol and octadecyl alcohol; The catalyst comprises an organic metal catalyst, and the solvent comprises an alcohol ether solvent.

6. The method for preparing the waterborne polyurethane thickener with good fluidity according to any one of claims 1 to 5, characterized in that: The following steps are involved: 1) Purifying the polyether diol; 2) adding a catalyst and an isocyanate to the purified polyether diol, and reacting under the protection of an inert gas to obtain a reactant; 3) Chain extender A, chain extender B and end capping agent are sequentially added to the reactants for reaction, and the remaining raw materials are added after cooling to obtain a waterborne polyurethane thickener with good fluidity.

7. The preparation method according to claim 6, characterized in that: The purification treatment is to heat the polyether diol to 110-130° C. and evacuate the mixture for 3-4 hours.

8. The preparation method according to claim 6 or 7, characterized in that: In the step 2), the reaction temperature is 60-80° C. and the reaction time is 2-4 hours.

9. The preparation method according to claim 8, characterized in that: The chain extender A and the chain extender B are added to the reactants for reaction at a temperature of 90 to 120° C. for 2 to 3 hours; The end-capping agent is added to the reactants to react at a temperature of 110 to 130° C. for 4 to 6 hours.

10. The preparation method according to claim 9, characterized in that: The cooling temperature is 70-100°C.

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