Disclosure of Invention
The invention aims to provide a preparation method of a non-ionic water-based curing agent based on bio-based pentamethylene diisocyanate, which has high solid content, quick surface drying time, environmental protection and no pollution.
The second purpose of the invention is to provide a non-ionic water-based curing agent based on bio-based pentamethylene diisocyanate obtained by the preparation method.
The technical scheme adopted by the invention for solving the technical problems is as follows:
a preparation method of a non-ionic water-based curing agent based on bio-based pentamethylene diisocyanate comprises the following steps: heating the bio-based pentamethylene diisocyanate tripolymer after impurity removal to 40-100 ℃ under the protection of inert gas, then adding polyol, reacting for 4-6 hours, and cooling to 25-40 ℃ when the product is transparent, thus obtaining the non-ionic water-based curing agent based on the bio-based pentamethylene diisocyanate; the mass ratio of the bio-based pentamethylene diisocyanate trimer to the polyol is 100: 6.67 to 21.33.
The bio-based pentamethylene diisocyanate trimer is prepared by reacting bio-based pentamethylene diisocyanate monomers, and the obtained bio-based pentamethylene diisocyanate trimer does not contain any solvent. The bio-based pentamethylene diisocyanate monomer is synthesized by 1, 5-pentanediamine through a series of physical and chemical methods, the raw materials for synthesizing the 1, 5-pentanediamine come from renewable biomass resources and can be obtained by directly biotransformation of lysine with rich resources, and the synthesis process is green and has no potential safety hazard; in addition, the activity of the bio-based pentamethylene diisocyanate is between TDI and HDI, so that the modification can be well completed, and simultaneously, the reaction activity is higher during film forming, and the bio-based PDI paint curing agent has certain advantages in the aspects of film coating gloss, surface drying time, paint film fullness and the like compared with petrochemical HDI polymer curing agents.
The bio-based pentamethylene diisocyanate trimer is subjected to impurity removal in a reduced pressure distillation mode. Because the raw material for synthesizing the bio-based pentamethylene diisocyanate trimer is derived from bio-based materials and contains more impurities, and the impurities can have adverse effects on the synthesis process and the stability of the synthesized product, the bio-based pentamethylene diisocyanate trimer is subjected to reduced pressure distillation and impurity removal treatment before use.
And the reduced pressure distillation adopts a rotary evaporator, the pressure of the rotary evaporator is 5-60 mbar, the distillation temperature is 120-200 ℃, the distillation time is 20-60 min, and heavy components after reduced pressure distillation are collected.
The molecular weight of the polyalcohol is 200-1000. Preferably, the molecular weight of the polyol is 400-700.
The polyol comprises a polyether polyol.
The polyhydric alcohol is any one or more of polyethylene glycol, polyethylene glycol monomethyl ether, polypropylene glycol monomethyl ether, polyethylene glycol monobutyl ether and polypropylene oxide glycol.
The adding mode of the polyhydric alcohol is dropwise adding, and the dropwise adding is completed within 35-45 min.
The polyol is dried before use, and the drying treatment is to add a molecular sieve into the polyol and then dry the polyol in vacuum at 100-110 ℃ for 3-5 hours.
The inert gas is any one of nitrogen, helium and argon. Preferably, the inert gas is nitrogen.
A non-ionic water-based curing agent based on bio-based pentamethylene diisocyanate is prepared by the preparation method.
The solid content of the non-ionic water-based curing agent is 100%, the NCO value is 15-21%, and the viscosity is 1500-3500 cp.
The preparation method of the non-ionic water-based curing agent based on the bio-based pentamethylene diisocyanate takes bio-based material trimer (PDI) prepared from green, environment-friendly and renewable raw materials as the basis of water-based modification, and establishes the preparation method of the non-ionic water-based curing agent based on the bio-based polyisocyanate.
The preparation method of the nonionic water-based curing agent adopts a one-pot method, is simple to operate, easy to master the operation flow, less in side reaction in the reaction process, high in reliability, free of adding an organic solvent, safe and environment-friendly, and suitable for industrial production. The nonionic water-based curing agent prepared by the method can form a structure with hydrophilic groups facing to a water phase after being mixed with water or water-based resin, and the mutual repulsion of the hydrophilic groups enables a dispersed phase of polyisocyanate to be in a relatively stable state, so that the storage stability of the product is improved.
The non-ionic waterborne curing agent based on the bio-based pentamethylene diisocyanate has higher reaction activity, does not contain volatile solvent, has small viscosity and good storage stability, has faster coating film drying speed and smaller viscosity, can be well dispersed in water, has small dispersed particle size, can play a good role in crosslinking and curing in a two-component waterborne polyurethane coating, and has fast drying speed after coating, high gloss value, good yellowing resistance and excellent chemical resistance.
Detailed Description
The present invention will now be described in detail with reference to the accompanying drawings. This figure is a simplified schematic diagram, and merely illustrates the basic structure of the present invention in a schematic manner, and therefore it shows only the constitution related to the present invention.
The test methods and calculation methods used in the following examples are as follows:
determination of the NCO content: weighing according to national standard HG-T2409-1992, placing 1g (accurate to 0.001g) of sample in a conical flask with a ground plug, adding 25ml of toluene-cyclohexanone solution by using a pipette, and slightly shaking to completely dissolve the sample; adding 25ml of 0.2mol/L di-n-butylamine solution into a pipette, adding a plug, shaking for a plurality of minutes, and standing for 10 minutes; adding 25ml of absolute ethyl alcohol into a measuring cylinder, taking a 1% bromocresol ethanol solution as an indicator, and titrating by using a 0.15mol/L hydrochloric acid standard solution until the color is just yellow as an end point; two replicates were run with a blank run.
The isocyanate group (NCO) content is calculated as follows:
NCO%=(V0-V1)×CHCl×4.202/M×100%
in the formula: v0The blank test consumes the volume of the hydrochloric acid standard solution, ml;
V1-titration of the sample to consume a volume, ml, of hydrochloric acid standard solution;
CHCl-the molar concentration of the hydrochloric acid standard solution, mol/L;
m-mass of sample, g;
4.202-isocyanate group equivalent constant.
Measurement of viscosity: a BROOKFIELD RVDV-III type rotary viscometer is used for carrying out shear viscosity test on the non-ionic water-based curing agent based on the bio-based pentamethylene diisocyanate, a number 07 rotor is selected, the rotating speed is 60 revolutions per minute, and the test is carried out at room temperature.
Testing of particle size: 1g of a bio-based pentamethylene diisocyanate-based nonionic aqueous curing agent was added to 10ml of phosphate buffer solution to neutralize the emulsion, diluted to 1 wt% with deionized water, and the particle size of the emulsion was measured using a Malvern Zetasizenano ZS90 laser particle size tester (Markov instruments Co., Ltd., UK) at a test temperature of 25 ℃ for a stabilization time of 120 s.
And (3) infrared testing: the measurement was carried out by means of a Nicolet 8700 type Fourier transform infrared spectrometer manufactured by Nicolet instruments of America with a resolution of 4cm-1The number of scanning times is 48, and the scanning range is 4000cm-1-400cm-1Dissolving the product in butanone, coating the solution on KBr crystals, and testing after the butanone is completely volatilized.
Example 1
The preparation method of the non-ionic water-based curing agent based on the bio-based pentamethylene diisocyanate comprises the following steps:
1) carrying out reduced pressure distillation on the bio-based pentamethylene diisocyanate trimer for 30min under the conditions that the pressure is 10mbar and the temperature is 120 ℃ by using a rotary evaporator, and collecting heavy components after reduced pressure distillation to obtain the bio-based pentamethylene diisocyanate trimer after impurity removal;
2) then adding 200g of the bio-based pentamethylene diisocyanate tripolymer subjected to impurity removal in the step 1) into a four-neck flask, adding 26g of dehydrated polyethylene glycol monomethyl ether with the molecular weight of 450 at one time, stirring and heating to 80 ℃ in a nitrogen atmosphere, fully reacting for 6 hours, cooling to 25 ℃ when the product in the flask is clear and transparent, discharging, sampling and titrating to obtain the bio-based pentamethylene diisocyanate tripolymer; the dehydration treatment of the polyethylene glycol monomethyl ether specifically comprises the following steps: adding a molecular sieve into polyethylene glycol monomethyl ether, and then drying for 5 hours in vacuum at 100 ℃.
The non-ionic aqueous curing agent based on bio-based pentamethylene diisocyanate obtained in this example had an-NCO content of 20.2%, a viscosity of 1800cp measured, a viscosity of 2167cp measured after storage at 50 ℃ for 7 days, and an average particle size of 261.4nm measured.
The nonionic aqueous curing agent based on the bio-based pentamethylene diisocyanate trimer obtained in this example was subjected to an infrared test, and the results are shown in FIG. 1, and it can be seen from FIG. 1 that 2940cm-1And 2865cm-1Is represented by CH22274cm-1is-NCO, 464cm-1Is positioned at 1106cm which is the vibration absorption peak of an isocyanate ring-1The peak at C-O-C indicates the presence of polyether on the isocyanate ring.
Example 2
The preparation method of the non-ionic water-based curing agent based on the bio-based pentamethylene diisocyanate comprises the following steps:
1) carrying out reduced pressure distillation on the bio-based pentamethylene diisocyanate trimer for 1h by using a rotary evaporator under the conditions that the pressure is 20mbar and the temperature is 150 ℃, and collecting heavy components after reduced pressure distillation to obtain the bio-based pentamethylene diisocyanate trimer after impurity removal;
2) adding 600g of the bio-based pentamethylene diisocyanate tripolymer subjected to impurity removal in the step 1) into a four-neck flask, adding 68g of dehydrated polyethylene glycol with the molecular weight of 400, stirring, heating to 60 ℃, fully reacting for 4 hours, cooling when substances in the flask are clear and transparent, discharging after the temperature reaches 30 ℃, sampling and titrating to obtain the bio-based pentamethylene diisocyanate tripolymer; the dehydration treatment of the polyethylene glycol specifically comprises the following steps: adding molecular sieve into polyethylene glycol, and vacuum drying at 110 deg.C for 3 hr.
The non-ionic aqueous curing agent based on bio-based pentamethylene diisocyanate obtained in this example had a-NCO content of 20.7%. The viscosity was found to be 1933cp, the viscosity after storage at 50 ℃ for seven days was found to be 2219cp, and the average particle diameter was found to be 267.3 nm.
Example 3
The preparation method of the non-ionic water-based curing agent based on the bio-based pentamethylene diisocyanate comprises the following steps:
1) carrying out reduced pressure distillation on the bio-based pentamethylene diisocyanate trimer for 1h by using a rotary evaporator under the conditions that the pressure is 30mbar and the temperature is 170 ℃, and collecting heavy components after reduced pressure distillation to obtain the bio-based pentamethylene diisocyanate trimer after impurity removal;
2) adding 450g of the bio-based pentamethylene diisocyanate tripolymer subjected to impurity removal in the step 1) into a four-neck flask, dropwise adding 96g of dehydrated polyethylene glycol monomethyl ether (molecular weight is 200) into a constant-pressure funnel within 40 minutes, stirring and heating to 100 ℃ under an argon atmosphere, fully reacting for 5 hours, cooling to 40 ℃ when substances in the flask are clear and transparent, discharging, sampling and titrating to obtain the bio-based pentamethylene diisocyanate tripolymer; the dehydration treatment of the polyethylene glycol monomethyl ether specifically comprises the following steps: adding molecular sieve into polyethylene glycol monomethyl ether, and vacuum drying at 105 deg.C for 4 hr.
The non-ionic aqueous curing agent based on bio-based pentamethylene diisocyanate obtained in this example had a-NCO content of 15.2%, a viscosity of 2700cp measured, a viscosity of 3123cp measured after storage at a temperature of 50 ℃ for seven days, and an average particle diameter of 259.1nm measured.
Example 4
The preparation method of the non-ionic water-based curing agent based on the bio-based pentamethylene diisocyanate comprises the following steps:
1) carrying out reduced pressure distillation on the bio-based pentamethylene diisocyanate trimer for 20min under the conditions that the pressure is 60mbar and the temperature is 190 ℃ by using a rotary evaporator, and collecting heavy components after reduced pressure distillation to obtain the bio-based pentamethylene diisocyanate trimer after impurity removal;
2) adding 150g of bio-based pentamethylene diisocyanate tripolymer subjected to impurity removal in the step 1) into a four-neck flask, adding 18g of dehydrated polyethylene glycol monomethyl ether with the molecular weight of 800, stirring, heating to 90 ℃, fully reacting for 5 hours, cooling to 35 ℃ when substances in the flask are clear and transparent, discharging, sampling and titrating to obtain the bio-based pentamethylene diisocyanate tripolymer; the dehydration treatment of the polyethylene glycol monomethyl ether specifically comprises the following steps: adding molecular sieve into polyethylene glycol monomethyl ether, and vacuum drying at 105 deg.C for 4 hr.
The non-ionic aqueous curing agent based on bio-based pentamethylene diisocyanate of this example had a-NCO content of 20.9%, a viscosity of 2899cp when tested, and a viscosity of 3004cp after storage at a temperature of 50 ℃ for seven days, and an average particle diameter of 255.4nm when tested.
Comparative example
The preparation method of the nonionic aqueous curing agent of the comparative example comprises the following steps:
adding 200g of bio-based pentamethylene diisocyanate tripolymer which is not treated by a rotary evaporator into a four-neck flask, adding 26g of dehydrated polyethylene glycol monomethyl ether with the molecular weight of 450 at one time, stirring and heating to 80 ℃ in a nitrogen atmosphere, fully reacting for 6 hours, cooling when substances in the flask are clear and transparent, discharging after the substances reach room temperature, sampling and titrating to obtain the bio-based pentamethylene diisocyanate tripolymer.
The nonionic aqueous curing agent obtained in this comparative example had a-NCO content of 19.1%, a viscosity of 2700cp when measured, a viscosity of 3478cp when stored at 50 ℃ for 7 days, and an average particle diameter of 700.4nm when measured.
Experimental example 1
Self-made waterborne resin component: adding deionized water with the mass ratio of 9%, BYK-190 water-based dispersing agent with the mass ratio of 1.2%, Defoamer A363 Defoamer with the mass ratio of 0.036%, Dupont R-902 titanium dioxide with the mass ratio of 19.52% and bentonite with the mass ratio of 0.24% into a grinding tank in sequence, then adding a part of zirconium beads into the grinding tank for grinding until the fineness is less than or equal to 25 microns, then adding acrylic resin CTR-6013 with the mass ratio of 70%, stirring for 30min, then adding 0.1% of thickening agent BYK420 for adjusting the viscosity, uniformly stirring, and discharging and preparing the paint.
The nonionic aqueous curing agents prepared in examples 1 to 4 and comparative example, and the commercially available Shiquanhxing D-100 curing agent and the aqueous resin were mixed in a ratio of NCO: OH 1.2:1, stirred by hand, diluted with water to a suitable viscosity, formed into a plate according to the national standards and subjected to a paint film new energy test, and the results are shown in Table 1:
TABLE 1 Performance index of coating films obtained from examples 1 to 4 and comparative example curing agent
As is clear from the data in Table 1, the coating films obtained from the curing agents of examples of the present invention are more dispersible in a comparative amount of water, have a shorter open time and a higher gloss value, and are excellent in impact resistance, abrasion resistance and water resistance.
The non-ionic waterborne curing agent in the embodiment of the invention takes the bio-based Pentamethylene Diisocyanate (PDI) tripolymer prepared from the green and environment-friendly bio-based material source with renewable raw materials as the basis of waterborne modification, and adopts the polyalcohol to carry out the non-ionic modification on the bio-based Pentamethylene Diisocyanate (PDI) tripolymer, the preparation method is simple and environment-friendly, does not contain volatile solvent, the obtained product can form a structure with a hydrophilic group facing to a water phase after being mixed with water, the structure can protect isocyanate groups, and the mutual repulsion of hydrophilic groups ensures that a dispersed phase of polyisocyanate is in a relatively stable state, further leading the non-ionic water-based curing agent to have the advantages of small viscosity, high storage stability and easy dispersion in water-based polymers, being used in the two-component water-based polyester, after coating, the paint has the characteristics of high drying speed, high fullness, high gloss value, strong pollution resistance, good yellowing resistance and the like.
Experimental example 2
4g of the bio-based Pentamethylene Diisocyanate (PDI) -based nonionic aqueous curing agent synthesized in example 1 was compared with an HDI-based aqueous curing agent (exemplified by commercially available Shi Quanxing D-100 curing agent), and the two were added to a mixed solution of 14g of butanol and 2g of xylene, respectively, reacted at 60 ℃ for 0.5h, 1h, and 1.5h, measured in sequence every 0.5h, and changes in NCO and refractive index were measured, and the conversion was monitored, and the results are shown in FIG. 2.
As can be seen from FIG. 2, the reaction activity of the PDI type aqueous curing agent with butanol was higher and the NCO conversion rate was higher in the same time as compared with the HDI type nonionic aqueous curing agent (exemplified by commercially available Shipanxing D-100 curing agent) in example 1, i.e., when the PDI type aqueous curing agent in example 1 was used in combination with a hydroxyl resin to prepare a coating film, the reaction with the hydroxyl resin was faster, and it was also confirmed that the PDI type aqueous curing agent had a faster open time in preparing the coating film.
In light of the foregoing description of preferred embodiments in accordance with the invention, it is to be understood that numerous changes and modifications may be made by those skilled in the art without departing from the scope of the invention. The technical scope of the present invention is not limited to the contents of the specification, and must be determined according to the scope of the claims.