A kind of preparation method of the whisker modified aqueous polyurethane of amination nano-celluloseTechnical field
The present invention relates to field of waterborne polyurethane, and in particular to a kind of whisker modified aqueous poly- ammonia of amination nano-celluloseThe preparation method of ester.
Background technique
Flexible package uses material often to use polyurethane (PU) as raw material, but traditional polyurethane products usually contain and largely haveSolvent exacerbates environmental pollution to a certain extent, therefore is gradually replaced by environmental-friendly aqueous polyurethane (WPU).But it is aqueousPolyurethane causes the mechanical property of material, thermal stability poor since there are hydrophilic functional groups in its structure, and can not match in excellence or beauty biography completelyThe solvent borne polyurethane of system.And traditional polyurethane products are often using non-renewable petroleum base dihydric alcohol as raw material, at present faceFace the scarcity of petroleum resources, people need to find a kind of reproducible raw material of green to substitute.
Castor oil is a kind of raw material of natural reproducible, and yield is big (crops that the whole world is planted extensively), environmentally protective,And be present in castor oil molecule there are three unsaturated conjugated double bond, be introduced into the molecule connection of polyurethane can make it is aqueousPolyurethane forms cross-linked structure, improves the mechanical property of aqueous polyurethane, while improving this inedible plant of castor oilApplication of the object oil in terms of aqueous polyurethane, is consistent with environmentally protective theory.
For the deficiency in terms of the mechanical property of aqueous polyurethane, heat resistance, technical staff both domestic and external has been done largelyResearch work, in terms of being modified main research to it at this stage.Nano material addition modification is current improvement aqueous polyurethane powerLearn performance and hot property effect method the most significant.Based on the above research, the present invention utilizes amination nano-cellulose whiskerWith the chemical bond hydrogen bond action of polyurethane matrix and itself excellent thermal stability to waterborne polyurethane modified.
Summary of the invention
The purpose of the present invention is to provide a kind of preparation method of whisker modified aqueous polyurethane of amination nano-cellulose,Overcome some defects existing for current aqueous polyurethane, this method can effectively reduce the pollution to environment, significantly improve aqueousThe mechanical property and thermal stability of polyurethane material, are able to satisfy the requirement of food-grade packing material.
In order to achieve the above objectives, the technical solution adopted by the present invention is that: a kind of whisker modified water of amination nano-celluloseThe preparation method of property polyurethane, successively includes the following steps:
The synthesis of amination nano-cellulose whisker: microcrystalline cellulose is dried in vacuo water removal, so by step (1) at 60 ~ 70 DEG CAfter the concentrated sulfuric acid is added, to be stirred to react 1 ~ 2 hour under 400 ~ 500 revs/min at 40 ~ 50 DEG C, observe reaction system color extremelyYellowish-brown stops reaction, and deionized water is added to stop reacting, and the amount that water is added is 5 ~ 10 times of reaction system volume；RetainLower layer's suspension washs suspension 3 ~ 4 times in 9500-10000 revs/min of lower high speed centrifugation, then through dialysing to neutrality, 40Nano-cellulose whisker is made after being dried in vacuo at ~ 50 DEG C；
Then, by the nano-cellulose whisker, silane coupling agent and volume fraction be 95% ethanol solution according to mass ratio1:0.16:50 mixing, the pH to 4 ~ 5 of reaction system is adjusted with glacial acetic acid, reacts 1 ~ 2 hour at 45 ~ 55 DEG C, finally uses ethyl alcoholAfter centrifuge washing 3 ~ 4 times, it is dried in vacuo 24 ~ 36 hours at 70 ~ 80 DEG C, obtains amination nano-cellulose whisker；
Step (2), by isophorone diisocyanate and castor oil, drying 10 ~ 15 is small in 100 ~ 105 DEG C of vacuum ovenShi Hou is sequentially added in reaction kettle, then amination nano-cellulose whisker is added into reaction kettle, is passed through protection gas nitrogen, is risenTemperature is stirred to react 1 ~ 2 hour under 500 ~ 600 revs/min to 75 ~ 85 DEG C, Waterborne Polyurethane Prepolymer can be obtained；
Step (3), when the mass percent of-NCO functional group in the Waterborne Polyurethane Prepolymer no longer changes, addition is dissolved inN, the chain extender 2 in N dimethyl pyrrolidones, 2- dihydromethyl propionic acid and octoate catalyst stannous, keep temperature fluctuations ± 2DEG C, to be stirred to react 3 ~ 4 hours under 600 ~ 700 revs/min, it is suitably added the viscosity of acetone control system；
Step (4), when the reaction system of the step (3) is cooled to 45 ~ 55 DEG C, addition triethylamine, 30 ~ 40 points of insulated and stirredClock, to after reaction, be down to room temperature；
Step (5), ethylenediamine is added to the water, ethylenediamine solution is uniformly mixing to obtain, wherein the quality of water is ethylenediamine matter90 ~ 100 times of amount；Again the system in the step (4) is cooled to 5 ~ 10 DEG C in a kettle, it is molten that the ethylenediamine is addedLiquid, with 1800 ~ 2000 revs/min emulsification pretreatment 30 ~ 40 minutes, obtain modified emulsion.
Preferably, the hydroxyl value of the castor oil is 160 ~ 165 mgKOH/g, average functionality is 2.5 ~ 2.8.
Preferably, the amination nano-cellulose whisker is made certainly by laboratory, the amination nano-celluloseThe additional amount of whisker is the 0.25 ~ 1% of the Waterborne Polyurethane Prepolymer quality.The raw material castor oil and as modifying agentAmination nano-cellulose whisker be natural reproducible resource.
Preferably, the isophorone diisocyanate and the molar ratio of castor oil are 1.4 ~ 1.8:1.
Preferably, the N, N dimethyl pyrrolidones, 2,2- dihydromethyl propionic acid, triethylamine and stannous octoateMolar ratio is 2:1:1:0.15.
Preferably, the mass fraction of the concentrated sulfuric acid is 56% in the step (1), the concentrated sulfuric acid and microcrystalline celluloseRatio be 15 mL:1g.
Preferably, in the step (5), with 1800 ~ 2000 revs/min emulsification pretreatment 30 ~ 40 minutes.
Compared with prior art, the beneficial effects of the present invention are:
1, the present invention is raw material using renewable, degradable castor oil, and amination nano-cellulose whisker is modifying agent, greenEnvironmental protection, it is cheap and easy to get, the dependence to petroleum resources is reduced to a certain extent.
2, modified aqueous polyurethane crosslinking degree prepared by the present invention is high, excellent in mechanical performance.
3, modified aqueous polyurethane matrix prepared by the present invention is after accessing amination nano-cellulose whisker, thermostabilizationProperty be improved significantly.
Specific embodiment
The present invention will be further described below with reference to examples:
NCO content of the invention is detected according to HG/T2409-1992 standard；Hydroxyl value according to ASTMD 4247-99 standard intoRow detection；Tensile strength testing standard is detected according to GB/T1040-1992 standard.
Embodiment 1
A kind of preparation method of the whisker modified aqueous polyurethane of amination nano-cellulose, comprising the following steps:
The synthesis of amination nano-cellulose whisker: microcrystalline cellulose is dried in vacuo water removal, then by step (1) at 70 DEG CAdditional proportion is 15:1(mL/g) 56%(mass fraction) concentrated sulfuric acid, to be stirred to react 2 hours under 500 revs/min at 50 DEG C,The deionized water of 6 times of systems is added to stop reacting, retains lower layer's suspension, by suspension under 9500 revs/min high speed fromThe heart washs 4 times, then through dialysing to neutrality, and nano-cellulose whisker is made after being dried in vacuo at 50 DEG C；
Then by above-mentioned nano-cellulose whisker and silane coupling agent, 95%(volume fraction) ethanol solution is according to 1:0.16:50(mass ratio) adjusts pH to 5 with glacial acetic acid, reacts at 45 DEG C 2 hours, after finally using ethyl alcohol centrifuge washing 3 times, at 80 DEG CVacuum drying 24 hours, obtains amination nano-cellulose whisker:
Step (2), by 27.8g isophorone diisocyanate, 34.2g castor oil dry 12 in 100 DEG C of vacuum ovenAfter hour, sequentially adds in reaction kettle, add the 0.25% amination Nanowire for accounting for the Waterborne Polyurethane Prepolymer qualityPlain whisker is tieed up, protection gas nitrogen is passed through, is warming up to 80 DEG C, is stirred to react under 500 revs/min 1 hour, aqueous poly- ammonia can be obtainedEster performed polymer；
Step (3), until when the mass fraction of-NCO functional group no longer changes in above-mentioned Waterborne Polyurethane Prepolymer ,-NCO% is23.1%, it adds and is dissolved in 6.4g N, the chain extender 3.2g 2 in N dimethyl pyrrolidones, 2- dihydromethyl propionic acid, catalyst0.48g stannous octoate is suitably added the viscosity of 50mL acetone control system to be stirred to react 3 hours under 600 revs/min；
Step (4) is cooled to 50 DEG C to above-mentioned reaction system, is added 2.6g triethylamine, and insulated and stirred 30 minutes, to the end of reactingAfterwards, it is down to room temperature；
Step (5), ethylenediamine is add to deionized water, ethylenediamine solution is uniformly mixing to obtain, wherein the quality of water is second90 times of diamines quality；Again the system in the step (4) is cooled to 5 DEG C in a kettle, the ethylenediamine solution is added,With 1800 revs/min emulsification pretreatment 30 minutes, obtain modified emulsion.
Embodiment 2
A kind of preparation method of the whisker modified aqueous polyurethane of amination nano-cellulose, comprising the following steps:
The synthesis of amination nano-cellulose whisker: microcrystalline cellulose is dried in vacuo water removal, then by step (1) at 75 DEG CAdditional proportion is 15:1(mL/g) 56%(mass fraction) concentrated sulfuric acid, to be stirred to react 2 hours under 600 revs/min at 50 DEG C,The deionized water of 8 times of systems is added to stop reacting, retains lower layer's suspension, by suspension under 9500 revs/min high speed fromThe heart washs 4 times, then through dialysing to neutrality, and nano-cellulose whisker is made after being dried in vacuo at 50 DEG C；
Then by above-mentioned nano-cellulose whisker and silane coupling agent, 95%(volume fraction) ethanol solution is according to 1:0.16:50(mass ratio) adjusts pH to 4 with glacial acetic acid, reacts at 45 DEG C 2 hours, after finally using ethyl alcohol centrifuge washing 3 times, at 80 DEG CVacuum drying 30 hours, obtains amination nano-cellulose whisker:
Step (2), by 27.1g isophorone diisocyanate, 35.7g castor oil dry 12 in 100 DEG C of vacuum ovenAfter hour, sequentially adds in reaction kettle, add the 0.50% amination Nanowire for accounting for the Waterborne Polyurethane Prepolymer qualityPlain whisker is tieed up, protection gas nitrogen is passed through, is warming up to 80 DEG C, is stirred to react under 500 revs/min 1 hour, aqueous poly- ammonia can be obtainedEster performed polymer；
Step (3), until when the mass fraction of-NCO functional group no longer changes in above-mentioned Waterborne Polyurethane Prepolymer ,-NCO% is21.3%, it adds and is dissolved in 7.2g N, the chain extender 3.6g 2 in N dimethyl pyrrolidones, 2- dihydromethyl propionic acid, catalyst0.60g stannous octoate is suitably added the viscosity of 56mL acetone control system to be stirred to react 3 hours under 600 revs/min；
Step (4) is cooled to 50 DEG C to above-mentioned reaction system, is added 2.9g triethylamine, and insulated and stirred 30 minutes, to the end of reactingAfterwards, it is down to room temperature；
Step (5), ethylenediamine is add to deionized water, ethylenediamine solution is uniformly mixing to obtain, wherein the quality of water is second95 times of diamines quality；Again the system in the step (4) is cooled to 5 DEG C in a kettle, the ethylenediamine solution is added,With 2000 revs/min emulsification pretreatment 35 minutes, obtain modified emulsion.
Embodiment 3
A kind of preparation method of the whisker modified aqueous polyurethane of amination nano-cellulose, comprising the following steps:
Microcrystalline cellulose: being dried in vacuo water removal by the synthesis of step (1) amination nano-cellulose whisker at 65 DEG C, then plusEntering ratio is 15:1(mL/g) 56%(mass fraction) concentrated sulfuric acid adds to be stirred to react 2 hours under 500 revs/min at 45 DEG CEnter the deionized water of 9 times of systems to stop reacting, retains lower layer's suspension, by suspension in 10000 revs/min of lower high speed centrifugationsWashing 4 times, then through dialysing to neutrality, nano-cellulose whisker is made after being dried in vacuo at 50 DEG C；
Then by above-mentioned nano-cellulose whisker and silane coupling agent, 95%(volume fraction) ethanol solution is according to 1:0.16:50(mass ratio) adjusts pH to 4.5 with glacial acetic acid, reacts at 45 ~ 55 DEG C 2 hours, after finally using ethyl alcohol centrifuge washing 4 times,It is dried in vacuo 32 hours at 80 DEG C, obtains amination nano-cellulose whisker:
After step (2) dries above-mentioned isophorone diisocyanate, castor oil 12 hours in 105 DEG C of vacuum oven,It sequentially adds in reaction kettle, adds the 0.75% amination nano-cellulose crystalline substance for accounting for the Waterborne Polyurethane Prepolymer qualityMust, it is passed through protection gas nitrogen, 85 DEG C is warming up to, is stirred to react under 500 revs/min 2 hours, aqueous polyurethane pre-polymerization can be obtainedBody；
When the mass fraction of-NCO functional group no longer changes in step (3) to above-mentioned Waterborne Polyurethane Prepolymer ,-NCO% is25.2%, addition is dissolved in 8gN, the chain extender 4g 2 in N dimethyl pyrrolidones, and 2- dihydromethyl propionic acid, 0.60g catalyst are pungentThe viscosity of 65mL acetone control system is added to be stirred to react 3 hours under 700 revs/min in sour stannous；
Step (4) is cooled to 45 DEG C to above-mentioned reaction system, is added triethylamine, and insulated and stirred 40 minutes, to after reaction, dropTo room temperature；
Step (5), 3.25g ethylenediamine is add to deionized water, ethylenediamine solution is uniformly mixing to obtain, wherein the matter of waterAmount is 100 times of ethylenediamine quality；Again the system in the step (4) is cooled to 5 DEG C in a kettle, the second two is addedAmine aqueous solution, with 2000 revs/min emulsification pretreatment 30 minutes, obtain modified emulsion.
Embodiment 4
A kind of preparation method of the whisker modified aqueous polyurethane of amination nano-cellulose, comprising the following steps:
Microcrystalline cellulose: being dried in vacuo water removal by the synthesis of step (1) amination nano-cellulose whisker at 70 DEG C, then plusEntering ratio is 15:1(mL/g) 56%(mass fraction) concentrated sulfuric acid adds to be stirred to react 2 hours under 500 revs/min at 50 DEG CEnter the deionized water of 10 times of systems to stop reacting, retain lower layer's suspension, by suspension under 10000 revs/min high speed fromThe heart washs 4 times, then through dialysing to neutrality, and nano-cellulose whisker is made after being dried in vacuo at 50 DEG C；
Then by above-mentioned nano-cellulose whisker and silane coupling agent, 95%(volume fraction) ethanol solution is according to 1:0.16:50(mass ratio) adjusts pH to 4 with glacial acetic acid, reacts at 55 DEG C 2 hours, after finally using ethyl alcohol centrifuge washing 4 times, at 80 DEG CVacuum drying 36 hours, obtains amination nano-cellulose whisker:
Step (2) is dry in 105 DEG C of vacuum oven by above-mentioned 35.4g isophorone diisocyanate, 36.3g castor oilIt after 13 hours, sequentially adds in reaction kettle, adds the amination Nanowire for accounting for 1 % of the Waterborne Polyurethane Prepolymer qualityPlain whisker is tieed up, protection gas nitrogen is passed through, is warming up to 85 DEG C, is stirred to react under 600 revs/min 2 hours, aqueous poly- ammonia can be obtainedEster performed polymer；
When the mass fraction of-NCO functional group no longer changes in step (3) to above-mentioned Waterborne Polyurethane Prepolymer ,-NCO% is26.4% addition is dissolved in 8.6gN, chain extender 4.3g2,2- dihydromethyl propionic acid, 0.79g catalyst in N dimethyl pyrrolidonesStannous octoate is suitably added the viscosity of acetone control system to be stirred to react 4 hours under 700 revs/min；
Step (4) is cooled to 45 DEG C to above-mentioned reaction system, is added triethylamine, and insulated and stirred 40 minutes, to after reaction, dropTo room temperature；
Step (5), ethylenediamine is add to deionized water, ethylenediamine solution is uniformly mixing to obtain, wherein the quality of water is second100 times of diamines quality；Again the system in the step (4) is cooled to 5 DEG C in a kettle, it is molten that the ethylenediamine is addedLiquid, with 2000 revs/min emulsification pretreatment 40 minutes, obtain modified emulsion.
Modified aqueous polyurethane emulsion obtained solidifies 48 hours at 60 DEG C, polyurethane film surface light in solidification processIt is sliding, do not occur the reunion crack often occurred after nanoparticle addition.
Performance test；The heat resistance of polyurethane film is through the thermogravimetic analysis (TGA) of Switzerland's plum Teller-support benefit Instrument Ltd.Instrument (TG) (model TGA/1100SF) test, temperature test section are 25 ~ 600 DEG C, and the tensile strength of film is through Jinan blue streak electromechanicsTechnology Co., Ltd.'s film stretching strength determination instrument (model XLW PC) test, 25 DEG C of test condition room temperature, test result is 5 timesAverage value.
Table 1 adds the ammonia of different content in the home position polymerization reaction of amination modifying nanometer cellulose aqueous polyurethaneInfluence of the base nano-cellulose whisker to thermal stability and tensile strength
| Amination nano-cellulose whisker additive amount (%) | 0 | 0.25 | 0.50 | 0.75 | 1.00 |
| Heat resistance (temperature of initial decomposition DEG C) | 202 | 206 | 221 | 233 | 246 |
| Tensile strength (Mpa) | 17.56 | 23.99 | 27.96 | 25.66 | 21.35 |
The temperature resistance data of embodiment one to example IV, which can be seen that, from table 1 is added to amination nano-cellulose whiskerThe temperature of initial decomposition of water-base polyurethane material be substantially better than general no added aqueous polyurethane.Embodiment one is to embodimentFour mechanical property is significantly stronger than the aqueous polyurethane for not adding amination nano-cellulose whisker.
The above embodiments merely illustrate the technical concept and features of the present invention, and its object is to allow person skilled in the artScholar cans understand the content of the present invention and implement it accordingly, and it is not intended to limit the scope of the present invention.It is all according to the present inventionEquivalent change or modification made by Spirit Essence, should be covered by the protection scope of the present invention.