Background technology
Super absorbent resin (SAP) is since since 20 century 70s developments and suitability for industrialized production, and the super absorbent resin that vinylformic acid and Acrylates thereof carry out crosslinking polymerization gained is because its raw material is easy to get, cheap for manufacturing cost, products obtained therefrom excellent performance becomes the current product that generalizes large-scale industrial production most.And be applied to paper diaper, the performance requriements of the super absorbent resin of the health fields such as sanitary napkin has experienced three phases, from the initial saturated liquid absorption of emphasizing merely water-absorbing resin, to emphasizing the liquid absorption that pressurizes, so far requiring product to have low residual monomer amount, low water soluble, to go out thing, high pressurization liquid absorbency rate, uptake rate fast, more require simultaneously the gel of absorbent resin after imbibition swelling have excellent liquid transmitting capacity and storageability (material depositing with use procedure in anti-yellowing change and anti-moisture absorption conglomeration performance).
Conventionally the polymer gel obtaining through polymerization must, through super-dry, disclose the dry of polymkeric substance in the 87-93 page of " modern high water absorbency polymer technology " monograph.For dry polymer gel, preferably use and force air conveyor dryer, dry material water content is preferably 1-5%.
The preparation method of the water-absorbing polymeric particles that residual monomer content is low has been described in EP289 338A1.In polymer gel dry, use by the air of high pressure steam heating, by part cycle gas, under closed-loop control, the high pressure steam that adds warm air flowing into is adjusted to desirable value.
For improving the hydraulic permeability of swell gel after the pick up of product under high capacity and imbibition, preferably dried particle is pulverized, to obtain the particle that reaches qualified size distribution, then carry out the surface-crosslinked reaction of particle.For example: CN1616525A(day touches), CN 1715302A(University Of Suzhou), CN1475517A(day touches).Although the liquid absorbency rate of the SAP resin after surface-crosslinked under load obviously improves, and the gel liquid transmitting capacity after imbibition swelling is not improved.In CN101531728(Shandong), CN1856331A(BASF), after surface-crosslinked processing or in surface-crosslinked reaction process, at SAP particle surface, adding the auxiliary agent that improves gel brine stream conductance, the auxiliary agent adding can be polyvalent metal salt class or inorganic powder class.
Above processing method can not be improved current health field all sidedly for the properties requirement of super absorbent resin.Adopt process production techniques of the present invention, can realize more all sidedly the low residual acrylic monomer of absorbent resin product, low water soluble goes out thing, after the high-liquid absorbing rate under load and imbibition, gel liquid perviousness and powder granule have the properties such as good anti-xanthochromia and damp proof conglomeration in put procedure.
The present invention is mainly achieved through the following steps: 1) by take Raolical polymerizable mode on continuous circulation band, obtain the high water absorbent resin gel that water content is 50% wide cut and carry out granulation, add redox initiator solution in gel granulation process; Then the good gel particle of this granulation is distributed to the travelling belt of recirculated air belt machine by a swing hydraulic pressure material distributing machine, before being dried, by a screeder by gel masses the transversely uniform thickness of travelling belt distribute, thereby gel masses can be evenly dried at three follow-up drying stages (constant drying rate stage, dry reduction of speed section, cooling section) effectively.By regulating air intake hot blast temperature, the intake velocity of dry three phases, with each section of desiccant gel water-content, the monomer that makes gel particle polymerization stage can not had initiator complete reaction and that add in gel granulation process to left behind with polymerization at constant drying rate stage fully reacts, thereby residual acrylic monomer content and water soluble apparent extract in the final dried particles obtaining are minimized; And at the dry high temperature of reduction of speed section, under the condition of high wind speed, aqueous gel particle is dried rapidly, reach the required more excellent particle water content (5-8%) of follow-up pulverizing ground section.The SAP particle that drying reduction of speed section water content is qualified is cooled to follow-up pulverizing at dry cooling section and grinds required temperature of charge (50-80 ℃).Thus obtained dried material obtains the Super Absorbent Polymer Particles of qualified particle diameter through follow-up pulverizing, grinding, screening; Then thering is the Super Absorbent Polymer Particles surface-coated surface crosslinking agent of qualified particle diameter, carry out heat treated, thereby in material process of cooling, add the super absorbent resin product of the properties excellence that color stabilizer and the damp proof conglomeration agent of particle obtain.
Summary of the invention
The object of this invention is to provide a kind of manufacture method with high performance absorbent resin, for realizing the super absorbent resin of manufacturing, there is excellent every over-all properties (low residual monomer content, low water soluble go out thing, high capacity pick up, hydraulic permeability that imbibition swell gel is high etc.).
A preparation method for high-performance water-absorbing resin, is characterized in that: the method comprises the steps:
(1) by obtaining the high water absorbent resin gel that water content is 50wt% wide cut and carry out granulation by take Raolical polymerizable mode on continuous circulation band, in gel granulation process, add oxidation, reduction initiator;
(2) gel particle that is 55wt% by the good water content of granulation is uniformly distributed on recirculated air belt machine and is dried, this drying process was divided into for three stages, that is: constant drying rate stage, dry reduction of speed section and dry cooling section, according to the changing conditions of different drying stage gel water content, regulate the inlet air temperature of drying machine warm air and the inflow velocity of warm air;
(3) qualified particle diameter is pulverized, grinds, sieved out to resulting dried material, qualified grain diameter is 100-850 μ m; After thering is the Super Absorbent Polymer Particles surface-coated surface crosslinking agent of qualified particle diameter, carry out heat treated, in material process of cooling, add the damp proof conglomeration agent of anti-yellowing additive and particle.
In step of the present invention (1), in gel granulation process, be oxidized the 10-200ppm that initiator addition is gel weight, reduction initiator addition is the 20-200ppm of gel weight.
In step of the present invention (3), the surface crosslinking agent of SiC p surface plating is selected from one or more in diglycidylether, alkylene carbonate or polyvalent alcohol, and its addition is 0.01wt%-2.0wt%; Its surface-crosslinked temperature of reaction is 100-210 ℃, and the reaction times is 20-90min.
In step of the present invention (2), through the good gel particle of granulation, by a swing hydraulic pressure material distributing machine, be uniformly distributed on recirculated air conveyor dryer, and then be evenly distributed on travelling belt being distributed in gel particle on drying machine travelling belt fabric thickness on request by a screeder, the gel thicknesses on drying machine travelling belt is 70-100mm.
In step of the present invention (2) at different drying stages, the test of desiccant gel particle water content be by continuously at sampling spot, sample and test in specific time spacer, get sample analysis result five times, deviation≤2 % by weight.
In step of the present invention (2), constant drying rate stage is divided into 1-3Ge district, between each district, by stainless steel heavy curtain, cut off, gel water content when constant drying rate stage completes is controlled as 20-35 % by weight, its temperature through the heated drying air after gel particle layer is controlled at 70-150 ℃, the speed control that warm air flows into, at 0.2-2.0m/s, is 10-20min in the constant drying rate stage residence time.
In step of the present invention (2), dry reduction of speed section is divided into 2-3Ge district, between each district, by stainless steel heavy curtain, cut off, when dry reduction of speed section completes, the water content of dried particles is 5-8 % by weight, temperature through the heated drying air after material bed is controlled at 150-180 ℃, the speed control that warm air flows into, at 1.0-5.0m/s, is 10-20min in the dry reduction of speed section residence time.
In step of the present invention (2), dry cooling section is used Yi Ge district, after cooling, the discharging material moisture of drying machine is 2-8 % by weight, drop temperature is controlled at 50-80 ℃, and the speed control that freezing air flows into, at 1.0-5.0m/s, is 3-10min in the residence time of cooling section.
The particle surface of the qualified particle diameter obtaining through super-dry, pulverizing, screening carries out coated surface linking agent, and by surface-crosslinked reacted high-performance water-absorbing resin (SAP) granule materials, in process of cooling, add anti-yellowing additive and damp proof conglomeration agent, anti-yellowing additive is wherein selected from one or more in calcium carbonate, sodium sulfate (magnesium), titanium dioxide, Vanadium Pentoxide in FLAKES, 2-hydroxyl-2-sulfino acetic acid disodium salt, quadrol, tetren, penten, and its addition is 0.1-3.0wt%; Damp proof conglomeration agent is selected from one or more in diatomite, silicon-dioxide, Tai-Ace S 150, sodium lauryl sulphate, polyoxyethylene laurel ether, Voranol EP 2001, and its addition is 0.1-3.0wt%.
By its residual acrylic monomer amount of the prepared absorbent resin of the present invention <100ppm, water soluble, go out thing <10 % by weight, suction salt solution multiplying power under 0.7psi load can >18g/g, the product of every excellent combination property such as gel permeation <30s after imbibition, it can be widely used in health field.And manufacturing process of the present invention is simple, is applicable to suitability for industrialized production.
Embodiment
The test of prepared absorbent resin properties is in the present invention implemented as follows:
1. residual acrylic monomer content in product:
Get 0.5g absorbent resin sample, be placed in the physiological saline of 100ml, stir after 0.5 hour, place 24 hours, then the resin of swelling is filtered, collect and the filtrate of the gained of weighing, filtrate is carried out to liquid-phase chromatographic analysis, then according to obtained peak area, filtrate quality and the vinylformic acid standardized solution curve demarcated in advance, calculate the content of residual acrylic monomer in institute's test sample product.
2. water soluble apparent extract in product:
In 250mL beaker, weigh the 184.3g0.9wt%NaCl aqueous solution, 1.00gSAP sample is joined in this solution, stir 16h to extract the soluble component in SAP sample.The solution of this extraction is filtered with filter paper, weigh 50.0g gained filtrate as measuring filtrate.First, carry out the titration of blank solution (aqueous solution of 0.9wt% NaCl), use the 0.1mol/LNaOH aqueous solution to carry out titration, until pH=10; Subsequently by using the titration of 0.1mol/L hydrochloric acid soln, until pH=2.7 obtains blank titration amount and is respectively [bNaOH], [bHCl] mL.Sample extraction liquid is carried out to above-mentioned same titration operation, obtain titer and be respectively [NaOH], [HCl] mL.Soluble component content Ex and the degree of neutralization DN of SAP sample can be calculated by following formula, wherein Mwfor molecular-weight average.
3. the pick up of product under load:
It is that 25mm has in the sieve right cylinder at the end that 0.2g sample is placed on to internal diameter, sample is applied to the load of 0.7psi, then this right cylinder is placed in to the culture dish of (± 2 ℃) physiological saline that has 25 ℃, allows it inhale physiological saline 1 hour, then surveys its liquid absorption.
4. the hydraulic permeability of product after imbibition swelling
Take and in the physiological saline that 0.32g test sample is positioned over 150g, stir and standing swelling 30 minutes, prepare aqueous gel particle.The embolism of the dead front type chromatographic column of the strainer with embolism and containing mark is closed, this embolism is made as to downside and vertically fixes this chromatographic column.With physiological saline in the physiological saline blank testing situation of 25 ℃ (± 2 ℃), flow through freely leading to the liquid time of fluid-through tube, write down as T1, the aqueous gel particle preparing is transferred in chromatographic column together with physiological saline, by at one end vertically with the pressuring shaft of the circular metal silk screen of sieve aperture, the mode that is positioned at aqueous gel particle one side according to wire cloth is put into, place again weight open fluid-through tube bottom valve in standing 1 minute, write down the flow through time T 2 of fluid-through tube of physiological saline.Required time is fewer, and the hydraulic permeability of product imbibition gel is better.The hydraulic permeability of product is: T2-T1,
5. the mensuration of moisture absorption caking rate
Absorbent resin using 2.00g as 850 μ m screen underflows or water absorbency resin composition are dispersed evenly to the cup end of the plastic cup of bottom surface diameter 50mm, height 11mm, put into fast in the climatic chamber that is adjusted in advance 25 ℃ of temperature, relative humidity 90RH%, place 1 hour.Thereafter, absorbent resin after moisture absorption or water absorbency resin composition are moved in the JIS standard sieve of diameter 7.5cm, mesh 200 μ m, utilize sieve shaker) sieve 5 minutes, mensuration residues in the weight of absorbent resin on sieve or water absorbency resin composition and by the absorbent resin of sieve or the weight of water absorbency resin composition, respectively as being W1 (g) and W2 (g).Then, by these weight (W1 and W2), calculate according to the following formula moisture absorption caking rate.In addition, adopt the mean value of 5 mensuration as the value of the moisture absorption caking rate of test sample, moisture absorption caking rate is lower, means that moisture absorption mobility is more excellent.Moisture absorption caking rate [%]=W1/ (W1+W2) * 100
6. sample yellowing resistance energy:
Sample is filled up to magazine, and test sample whiteness H1, then puts into sample in the climatic chamber that is adjusted in advance temperature 60 C, relative humidity 90RH%, and after 21 days, the whiteness H2 of test sample, then calculates its yellowing resistance.Anti-yellowing variability [%]=(H1-H2)/H1*100 numerical value is less, illustrates that its yellowing resistance is better.
Embodiment
The preparation of polymeric gel:
By continuous mixing water, the sodium hydroxide solution of 32 % by weight, vinylformic acid, the acrylic acid solution of polyoxyethylene glycol-200 diacrylate of 20 % by weight and to make solid content be 38 % by weight, degree of neutralization is 75% polymerization single polymerization monomer solution, this polymerization single polymerization monomer solution is cooled to 60 ℃ of left and right by an interchanger by temperature, then in this polymerization single polymerization monomer solution, add the ammonium persulfate aqueous solution of 3wt% and the sodium bisulfite of 1wt%, after mixing, be supplied to rapidly circulating belt polymerization reactor to carry out polymerization reactor, material residence time in polymerization reactor is 20min left and right, thereby obtain 550kg/h, water content is 50% left and right, wide cut is 600mm, thickness is the polymeric gel of 20mm.
This polymeric gel is cut apart by longitudinal, horizontal cutting knife, then at a screw extrusion press, carry out gel granulation, in granulation process, add the ammonium persulfate aqueous solution of 0.3wt% and the aqueous solution of sodium bisulfite of 0.1wt%, addition is 5% left and right of gel content, finally obtain 600-620kg/h, water content is 55wt% left and right, particle size is the gel particle of 10-20mm left and right, this gel granulation is uniformly distributed on forced hot air circulation conveyor dryer and is dried by a swing hydraulic pressure material distributing machine and rake screeder, and material bed thickness is 80mm.
Embodiment 1
Drying conditions is: constant drying rate stage divides 2 districts, and HAI Heated Air Intake temperature is 150-160 ℃, through material bed temperature, is 70-150 ℃, and gas flow rate is 1m/s, and the gel particle water content that goes out constant-speed section is 30wt% left and right, in the residence time of constant-speed section, is 15min; Dry reduction of speed section is also divided into 2 districts, HAI Heated Air Intake temperature is 160-180 ℃, through material bed temperature, be 150-180 ℃, gas flow rate is 3m/s, and the gel particle water content that goes out reduction of speed section is 6wt% left and right, material is 15min in the residence time of reduction of speed section, then dried material enters the cooling that dried material is carried out in cooling area, and this section of temperature is 50～80 ℃, and cooling gas flow velocity is 3m/s, this period of residence time is 5 minutes, and after the 3rd step is cooling, the water content of dried particles is 5wt%.
It is 380 μ m particles that the above-mentioned dry particle obtaining is obtained to average grain particle diameter through pulverizing, sub-sieve, this particle is carried out to surface crosslinking agent coating and reacting by heating, surface crosslinking agent is the mixture of glycerine, ethylene glycol and the water of 15 % by weight, its three's ratio is 2:1:7, reacting by heating temperature is 190 ℃, and the reaction times is 45min.To carry out cooling through surface-crosslinked reacted particle subsequently, when being cooled to 80 ℃ of left and right, the silicon-dioxide (particle <20 μ m) and the 2 % by weight sodium ethylene diamine tetracetate aqueous solution (100ppm) that add 1.0 % by weight, the absorbent resin product performance that finally obtain are in Table 1
Embodiment 2
Drying conditions, as embodiment 1, changes the gas flow rate of constant drying rate stage to 2.0m/s, in the residence time of constant-speed section, is 15min; The gel particle water content that goes out constant-speed section is 20wt% left and right, hot blast temperature and the gas flow rate of dry reduction of speed section do not change, in the gel particle water content that goes out reduction of speed section, be 4% left and right, the condition of dry cooling section is also as example 1, and after cooling, the water content of dried particles is 3wt%.
It is 380 μ m particles that the above-mentioned dry particle obtaining is obtained to average grain particle diameter through pulverizing, sub-sieve, resulting particle is carried out to particle surface processing as example 1, at particle, through surface-crosslinked reaction, be cooled to 70 ℃, add the Tai-Ace S 150 particle (particle <100 μ m) of 1.0 % by weight, and the polyoxyethylene sodium stearate aqueous solution (200ppm) of 2 % by weight.The absorbent resin product performance that finally obtain are in Table 1
Comparative example 1
Drying conditions is: constant drying rate stage divides 2 districts, HAI Heated Air Intake temperature is 150-160 ℃, through material bed temperature, is 120-150 ℃, and gas flow rate is 3m/s, the gel particle water content that goes out constant-speed section is 10wt% left and right, in the residence time of constant-speed section, is 15min; Dry reduction of speed section is also divided into 2 districts, HAI Heated Air Intake temperature is 160-180 ℃, through material bed temperature, be 150-180 ℃, gas flow rate is 3m/s, and the gel particle water content that goes out reduction of speed section is 2wt% left and right, material is 15min in the residence time of reduction of speed section, then dried material enters the cooling that dried material is carried out in cooling area, and this section of temperature is 50～80 ℃, and cooling gas flow velocity is 3m/s, this period of residence time is 5 minutes, and after cooling, the water content of dried particles is 2%.
It is 380 μ m particles that the above-mentioned dry particle obtaining is obtained to average grain particle diameter through pulverizing, sub-sieve, this particle is carried out to particle surface crosslinking reaction and the aftertreatment of particle in process of cooling by the method for embodiment 1, and the absorbent resin product performance that obtain are in Table 1
Comparative example 2
As the method for embodiment 1 carries out that gel particle is dry, pulverizing, sub-sieve and particle surface crosslinking reaction, in particle process of cooling, add the polyoxyethylene sodium stearate aqueous solution (200ppm) of 2 % by weight, the product performance that preparation reaches are in Table 1
Comparative example 3
As the method for embodiment 1 carries out that gel particle is dry, pulverizing, sub-sieve and particle surface crosslinking reaction, in particle process of cooling, add the diethylidene pentaacetic acid sodium water solution of 2 % by weight, the product performance that preparation reaches are in Table 1
Result shows, in institute of the present invention research range, the drying conditions of gel particle is for the residual monomer content of the finished product, pick up and gel permeation under water soluble apparent extract, load have impact, and in process of cooling, the interpolation of anti-moisture absorption conglomeration agent and anti-yellowing additive is for the gel permeation of the finished product, the impact of the anti-moisture absorption conglomeration of product and yellowing resistance is very large, so adopt manufacture method of the present invention, can prepare all products of excellence of every physics and use properties.