CN115007122B - Drying agent and preparation method thereof - Google Patents

Drying agent and preparation method thereof Download PDF

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CN115007122B
CN115007122B CN202210771176.1A CN202210771176A CN115007122B CN 115007122 B CN115007122 B CN 115007122B CN 202210771176 A CN202210771176 A CN 202210771176A CN 115007122 B CN115007122 B CN 115007122B
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moisture absorption
moisture
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water
silica gel
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CN115007122A (en
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戴增添
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Dongguan Dingxing Industry Co ltd
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/22Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising organic material
    • B01J20/26Synthetic macromolecular compounds
    • B01J20/265Synthetic macromolecular compounds modified or post-treated polymers
    • B01J20/267Cross-linked polymers
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D53/00Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/26Drying gases or vapours
    • B01D53/261Drying gases or vapours by adsorption
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D53/00Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/26Drying gases or vapours
    • B01D53/28Selection of materials for use as drying agents
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00Processes of polymerisation
    • C08F2/46Polymerisation initiated by wave energy or particle radiation
    • C08F2/48Polymerisation initiated by wave energy or particle radiation by ultraviolet or visible light
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F261/00Macromolecular compounds obtained by polymerising monomers on to polymers of oxygen-containing monomers as defined in group C08F16/00
    • C08F261/02Macromolecular compounds obtained by polymerising monomers on to polymers of oxygen-containing monomers as defined in group C08F16/00 on to polymers of unsaturated alcohols
    • C08F261/04Macromolecular compounds obtained by polymerising monomers on to polymers of oxygen-containing monomers as defined in group C08F16/00 on to polymers of unsaturated alcohols on to polymers of vinyl alcohol
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F290/00Macromolecular compounds obtained by polymerising monomers on to polymers modified by introduction of aliphatic unsaturated end or side groups
    • C08F290/02Macromolecular compounds obtained by polymerising monomers on to polymers modified by introduction of aliphatic unsaturated end or side groups on to polymers modified by introduction of unsaturated end groups
    • C08F290/06Polymers provided for in subclass C08G
    • C08F290/062Polyethers
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F8/00Chemical modification by after-treatment
    • C08F8/12Hydrolysis

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  • Engineering & Computer Science (AREA)
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  • Solid-Sorbent Or Filter-Aiding Compositions (AREA)

Abstract

The invention relates to the technical field of drying agents, in particular to a drying agent and a preparation method thereof, wherein the drying agent comprises a drying agent material bag and a drying agent body accommodated in the drying agent material bag, and the drying agent body comprises moisture absorption type resin and a plurality of silica gels attached to the surface of the moisture absorption type resin; the moisture absorption resin is prepared from the following raw materials: acrylic acid, acrylamide, polyvinyl alcohol, a crosslinking agent, a photoinitiator, water and sodium hydroxide solution. The surface of the moisture absorption type resin is adhered with a plurality of silica gels, the silica gels are used for absorbing moisture of air, the silica gels absorb water and are condensed into liquid water, and the liquid water directly contacts the moisture absorption type resin, so that the moisture absorption type resin can absorb the liquid water in the silica gels, the water absorption efficiency is improved, the integral water absorption capacity of the drying agent is increased, the saturated water absorption rate of the drying agent is increased, an unexpected effect is obtained in the actual application process, and the drying agent is applied to transportation environments such as sea transportation, freight transportation and the like, so that the cost is obviously saved.

Description

Drying agent and preparation method thereof
Technical Field
The invention relates to the technical field of drying agents, in particular to a drying agent and a preparation method thereof.
Background
Desiccants refer to substances that remove moisture from moist substances and are often classified into two categories: chemical desiccants, such as calcium sulfate and calcium chloride, dry by combining with water to form hydrates; physical desiccants, such as silica gel, activated alumina, and the like, dry by physically adsorbing water. Moisture management is closely related to the yield of the product. In the case of food products, at the proper temperature and humidity, bacteria and mold in the food can multiply at an alarming rate, spoil the food, and cause moisture and color change. The electronic products can also produce defective products due to metal oxidation caused by overhigh humidity. The desiccant is used to avoid the generation of defective products caused by excessive moisture.
Although the traditional chemical drying agent and physical drying agent can absorb water from the air to achieve the effects of drying and moisture prevention, the water absorption amount is low and the traditional chemical drying agent and physical drying agent are easy to saturate, so that the using amount of the drying agent needs to be increased to obtain more effective adsorption, the occupied space is larger, the weight is heavier, and the traditional chemical drying agent and physical drying agent are not beneficial to saving the cost when being applied to transportation environments such as maritime transportation, freight transportation and the like.
Disclosure of Invention
In order to overcome the disadvantages and shortcomings of the prior art, an object of the present invention is to provide a desiccant, wherein a plurality of silica gels are attached to the surface of the moisture-absorbing resin, and the silica gels are used for absorbing moisture in the air, so that the silica gels absorb water and condense into liquid water, which is more beneficial for the moisture-absorbing resin to absorb the liquid water in the silica gels, thereby increasing the overall water absorbing capacity of the desiccant and increasing the saturated water absorption rate of the desiccant.
The second purpose of the invention is to provide a preparation method of the drying agent, which has the advantages of simple operation, convenient control, high production efficiency and low production cost and can be used for large-scale production.
One of the purposes of the invention is realized by the following technical scheme: a desiccant comprises a desiccant material bag and a desiccant body accommodated in the desiccant material bag, wherein the desiccant body comprises moisture absorption type resin and a plurality of silica gels attached to the surface of the moisture absorption type resin;
the moisture-absorbing resin is prepared from the following raw materials in parts by weight:
Figure SMS_1
the desiccant provided by the invention adopts the desiccant bag as a carrier, the moisture absorption type resin with a plurality of silica gels attached to the surface is filled, the desiccant bag protects the moisture absorption type resin, the silica gels are attached to the surface of the moisture absorption type resin, the silica gels absorb moisture of air, the silica gels absorb water and are condensed into liquid water, and the liquid water is directly contacted with the moisture absorption type resin, so that the moisture absorption type resin can absorb the liquid water in the silica gels, the water absorption efficiency is improved, the integral water absorption capacity of the desiccant is increased, the saturated water absorption rate of the desiccant is increased, an unexpected effect is obtained in the actual application process, and the desiccant is applied to transportation environments such as sea transportation, freight transportation and the like, and the cost is remarkably saved.
In addition, the moisture-absorbing resin takes acrylic acid as a main body, and acrylamide, polyvinyl alcohol, a cross-linking agent, a photoinitiator, water and a sodium hydroxide solution are added, namely, the monomer residue obtained by photo-initiated polymerization is low, and the water and saline absorption effects are better under the weak acid or weak alkaline condition.
Preferably, the preparation method of each part of the cross-linking agent comprises the following steps:
a1, uniformly mixing 100 parts by weight of polyethylene glycol and 0.15-0.20 part by weight of polymerization inhibitor, adding 3-4 parts by weight of acrylic acid, 0.4-0.5 part by weight of esterification catalyst, 100-300 parts by weight of organic solvent and 150-300 parts by weight of cyclohexane, stirring, heating to 85-95 ℃, and preserving heat for 5-7 hours to obtain a crosslinked semi-finished product;
and A2, adding a sodium carbonate solution into the cross-linking semi-finished product to adjust the pH value to 6.5-7.5, washing, extracting, and drying under reduced pressure for 24 hours in vacuum to obtain the cross-linking agent.
By adopting the technical scheme, the preparation method of the cross-linking agent is characterized in that esterification catalysis is carried out under the action of an esterification catalyst, a polymerization inhibitor and cyclohexane, and the prepared cross-linking agent is particularly suitable for preparing the moisture-absorption resin disclosed by the invention, so that the moisture-absorption resin has a specific cross-linking degree, the moisture-absorption resin can form a porous network structure, and the water absorption rate is improved.
Preferably, the polymerization inhibitor is methyl hydroquinone or 2-tertiary butyl hydroquinone; the organic solvent is toluene, and the esterification catalyst is at least one of dicyclohexylcarbodiimide, N' -diisopropylcarbodiimide and 4-dimethylaminopyridine.
By adopting the technical scheme, the acrylic acid is prevented from self-polymerization, and the esterification rate of the cross-linking agent is improved, so that the formation of the moisture absorption resin with specific cross-linking degree under ultraviolet radiation is facilitated, and the moisture absorption rate is improved.
Preferably, the photoinitiator is alpha, alpha-dimethoxy-alpha-phenylacetophenone and 2,4-dihydroxybenzophenone in a weight ratio of 3:1-5, mixing; the concentration of the sodium hydroxide solution is 50-60wt%.
By adopting the technical scheme, the synergistic effect of the alpha, alpha-dimethoxy-alpha-phenylacetophenone and the 2,4-dihydroxybenzophenone is higher in polymerization initiating efficiency under ultraviolet radiation, the moisture absorption resin is promoted to obtain higher molecular weight, the water absorption rate is improved, and the monomer residue is reduced. The concentration of the sodium hydroxide solution is 50-60wt%, the neutralization degree of acrylic acid can be conveniently adjusted to 75-88% after the sodium hydroxide solution is added, and resin saponification is carried out, so that an unexpected effect is achieved on the water absorption and salt absorption rate of the moisture absorption resin under a weak acid or weak alkaline condition, and the monomer residue is reduced.
Preferably, the silica gel is fine-pore silica gel and/or coarse-pore silica gel; the particle size distribution of the silica gel is 230-460 meshes; the weight ratio of the moisture-absorbing resin to the silica gel is (100).
Adopt above-mentioned technical scheme, silica gel is a gel, microporous structure has, consequently, stronger adsorptivity has, pore silica gel and coarse pore silica gel belong to high active adsorption material, coarse pore silica gel has higher adsorption capacity under the high condition of relative humidity, pore silica gel then adsorption capacity is higher than coarse pore silica gel under the lower condition of relative humidity, utilize the moisture of silica gel adsorption air, silica gel water absorption is congealed into liquid water, liquid water direct contact moisture absorption type resin, more be favorable to the liquid water in the moisture absorption type resin absorption silica gel, improve water absorption efficiency. The weight part ratio of the moisture absorption resin to the silica gel is (100). More preferably, the silica gel is formed by mixing fine-pore silica gel and coarse-pore silica gel according to the weight ratio of 1:1-2.
The second purpose of the invention is realized by the following technical scheme: the preparation method of the drying agent comprises the following steps:
s, prefabricating a moisture-absorbing resin semi-finished product:
s1, taking acrylic acid, acrylamide, polyvinyl alcohol, a cross-linking agent, a photoinitiator, water and a plurality of sodium hydroxide solutions in parts by weight;
s2, adding acrylic acid into water according to the parts by weight, then adding a sodium hydroxide solution to adjust the neutralization degree of the acrylic acid to be 75-88%, and then adding polyvinyl alcohol, acrylamide, a cross-linking agent and a photoinitiator to be uniformly mixed to obtain a mixed solution;
s3, fully reacting the mixed solution at the temperature of 20-35 ℃ under stirring and ultraviolet radiation to obtain a reactant;
s4, adding a sodium hydroxide solution into the reactant, performing saponification reaction for 1-3h at 70-90 ℃, filtering, and dehydrating with 95% ethanol to obtain a semi-finished product of the moisture absorption type resin;
r, preparing moisture absorption type resin particles with a plurality of silica gels attached to the surfaces;
p, packaging: and filling the moisture absorption type resin particles into a desiccant bag, and sealing and storing to obtain the desiccant.
By adopting the technical scheme, in the step S of prefabricating the semi-finished product of the moisture-absorption type resin, sodium hydroxide is adopted to adjust the neutralization degree of acrylic acid to 75-88%, then polyvinyl alcohol, acrylamide, a special cross-linking agent and a special photoinitiator are added and mixed, then the UV radiation is adopted to promote full reaction under the stirring of 20-35 ℃, then sodium hydroxide solution is adopted to saponify the semi-finished product, then filtration and 95% ethanol dehydration are carried out, and the obtained semi-finished product of the moisture-absorption type resin has the characteristics of low monomer residue and better water absorption and saline absorption effects under the weak acidic or weak alkaline condition. The method is characterized in that the neutralization degree of acrylic acid, the dosage of a cross-linking agent and the dosage of a photoinitiator are controlled, the three components have synergistic effects to ensure that the moisture-absorbing resin has an excellent water absorption effect, and the combined action of polyvinyl alcohol and acrylamide and saponification reaction of reactants are combined to play an unexpected effect on the water absorption and water absorption rate of the moisture-absorbing resin under weak acid or weak alkaline conditions and reduce monomer residues. And step R, preparing the moisture absorption resin particles with a plurality of silica gels attached to the surfaces by using the moisture absorption resin semi-finished product so as to form a granular structure in the preparation process of the moisture absorption resin semi-finished product, and the water absorption effect is better. Furthermore, in the step S4, the added sodium hydroxide solution is 20-30 parts by weight and 50-60wt% in concentration.
Preferably, the irradiation of ultraviolet radiationThe degree is 0.8-1.4W/m 2 @340nm, and the irradiation time is 30-60min; in the step S3, the rotating speed of stirring is 100-200r/min.
By adopting the technical scheme, the wavelength is 340nm, and the irradiance is 0.8-1.4W/m 2 The ultraviolet radiation initiates polymerization, the product purity is higher, the synthesis time is short, the cost is lower, the polymerization temperature is easier to control by combining the environment of 20-35 ℃, and the influence on the overall water absorption effect of the moisture absorption resin caused by imploding caused by local overheating can be prevented; the stirring speed is 100-200r/min, the molecular weight of the polymerization product is promoted to be uniform, and the partial moisture absorption resin is prevented from being excessively crosslinked to reduce the water absorption.
Preferably, the method for preparing the moisture-absorption resin particles with a plurality of silica gels attached to the surfaces thereof comprises the following steps:
r1, taking 100 parts of moisture-absorbing resin semi-finished product, 1-5 parts of micron-sized zeolite powder with the particle size of 30-60 mu m, 5-20 parts of silica gel and a plurality of polyoxyethylene-water solutions with the concentration of 1-3wt% for later use;
r2, dripping polyoxyethylene-water solution into the semi-finished product of the moisture absorption resin to ensure that the water content of the semi-finished product reaches 32-50wt%, then adding micron-sized zeolite powder, and uniformly mixing to obtain a pre-formed granule;
and R3, adding silica gel into the preformed granules, and drying by adopting a drum dryer to obtain the moisture absorption resin granules with a plurality of silica gels attached to the surfaces.
By adopting the technical scheme, a plurality of silica gel moisture absorption resin particles are attached to the surface of the method, wherein the polyoxyethylene-water solution is dropwise added in the step R2 to ensure that the moisture content of the moisture absorption resin semi-finished product reaches 32-50wt%, so that the moisture absorption resin is favorably granulated, the particle size is equivalent, the strength is improved, and the water absorption capacity is improved; the micron-sized zeolite powder is added to facilitate granulation and dispersion of the moisture-absorbing resin, and the micron-sized zeolite powder has a porous adsorption structure and is more beneficial to water absorption; and step R3, adding silica gel, drying by a drum dryer, and attaching a plurality of silica gels to the surfaces of the moisture absorption resin particles and drying.
Further, the concentration of the polyoxyethylene-water solution is 1-3wt%; the particle size of the micron-sized zeolite powder is 30-60 mu m.
The invention has the beneficial effects that: the desiccant provided by the invention adopts the desiccant bag as a carrier, the moisture absorption type resin with a plurality of silica gels attached to the surface is filled, the desiccant bag protects the moisture absorption type resin, the silica gels are attached to the surface of the moisture absorption type resin, the silica gels absorb moisture of air, the silica gels absorb water and are condensed into liquid water, and the liquid water is directly contacted with the moisture absorption type resin, so that the moisture absorption type resin can absorb the liquid water in the silica gels, the water absorption efficiency is improved, the integral water absorption capacity of the desiccant is increased, the saturated water absorption rate of the desiccant is increased, an unexpected effect is obtained in the actual application process, and the desiccant is applied to transportation environments such as sea transportation, freight transportation and the like, and the cost is remarkably saved.
In addition, the moisture-absorbing resin takes acrylic acid as a main body, and acrylamide, polyvinyl alcohol, a cross-linking agent, a photoinitiator, water and a sodium hydroxide solution are added, namely, the monomer residue obtained by photo-initiated polymerization is low, and the water and saline absorption effects are better under the weak acid or weak alkaline condition.
The preparation method disclosed by the invention is simple to operate, convenient to control, high in production efficiency and low in production cost, and can be used for large-scale production.
Detailed Description
The present invention will be further described with reference to the following examples for facilitating understanding of those skilled in the art, and the description of the embodiments is not intended to limit the present invention.
Example 1
A desiccant comprises a desiccant material bag and a desiccant body accommodated in the desiccant material bag, wherein the desiccant body comprises moisture absorption type resin and a plurality of silica gels attached to the surface of the moisture absorption type resin;
the moisture-absorbing resin is prepared from the following raw materials in parts by weight:
Figure SMS_2
Figure SMS_3
the preparation method of each part of the cross-linking agent comprises the following steps:
a1, uniformly mixing 100 parts of polyethylene glycol and 0.18 part of polymerization inhibitor in parts by weight, then adding 3.5 parts of acrylic acid, 0.45 part of esterification catalyst, 200 parts of organic solvent and 200 parts of cyclohexane, stirring, heating to 90 ℃, and preserving heat for 6 hours to obtain a cross-linked semi-finished product;
and A2, adding a sodium carbonate solution into the crosslinking semi-finished product to adjust the pH value to 7.0, washing, extracting, and drying under vacuum and reduced pressure for 24 hours to obtain the crosslinking agent.
The polymerization inhibitor is methyl hydroquinone; the organic solvent is toluene.
The esterification catalyst is dicyclohexylcarbodiimide.
The photoinitiator is alpha, alpha-dimethoxy-alpha-phenylacetophenone and 2,4-dihydroxy benzophenone in a weight ratio of 3:3, mixing the components.
The silica gel is formed by mixing fine-pore silica gel and coarse-pore silica gel according to a weight ratio of 1.5; the particle size distribution of the silica gel is 325 meshes.
The preparation method of the drying agent comprises the following steps:
s, prefabricating a moisture-absorbing resin semi-finished product:
s1, taking acrylic acid, acrylamide, polyvinyl alcohol, a cross-linking agent, a photoinitiator, water and a plurality of sodium hydroxide solutions in parts by weight;
s2, adding acrylic acid into water according to parts by weight, then adding a sodium hydroxide solution with the concentration of 55wt% to adjust the neutralization degree of the acrylic acid to be 80%, and then adding polyvinyl alcohol, acrylamide, a cross-linking agent and a photoinitiator to be uniformly mixed to obtain a mixed solution;
s3, fully reacting the mixed solution at the temperature of 30 ℃ under the condition of stirring and ultraviolet radiation to obtain a reactant;
s4, adding 25 parts of sodium hydroxide solution with the concentration of 55wt% into the reactant, performing saponification reaction for 2 hours at the temperature of 80 ℃, and filtering and dehydrating with 95% ethanol to obtain a semi-finished product of the moisture absorption resin;
r, preparing moisture absorption type resin particles with a plurality of silica gels attached to the surfaces:
r1, taking 100 parts of a moisture-absorption resin semi-finished product, 3 parts of micron-sized zeolite powder with the particle size of 50 mu m, 15 parts of silica gel and a plurality of polyoxyethylene-water solutions with the concentration of 2wt% for later use;
r2, dripping polyoxyethylene-water solution into the semi-finished product of the moisture absorption resin to enable the water content of the semi-finished product to reach 40wt%, then adding micron-sized zeolite powder, and uniformly mixing to obtain a pre-formed particle;
r3, adding silica gel into the pre-granulated substance, and drying by adopting a drum dryer to obtain moisture absorption resin particles with a plurality of silica gels attached to the surfaces;
p, packaging: and filling the moisture absorption type resin particles into a desiccant bag, and sealing and storing to obtain the desiccant.
The irradiance of the ultraviolet radiation is 1W/m 2 @340nm, and the irradiation time is 40min; in the step S3, the rotating speed of stirring is 150r/min.
Example 2
A desiccant comprises a desiccant bag and a desiccant body accommodated in the desiccant bag, wherein the desiccant body comprises moisture absorption type resin and a plurality of silica gels attached to the surface of the moisture absorption type resin;
the moisture-absorbing resin is prepared from the following raw materials in parts by weight:
Figure SMS_4
the preparation method of each part of the cross-linking agent comprises the following steps:
a1, uniformly mixing 100 parts of polyethylene glycol and 0.15 part of polymerization inhibitor in parts by weight, adding 3 parts of acrylic acid, 0.4 part of esterification catalyst, 100 parts of organic solvent and 150 parts of cyclohexane, stirring, heating to 85 ℃, and preserving heat for 5 hours to obtain a cross-linked semi-finished product;
and A2, adding a sodium carbonate solution into the cross-linking semi-finished product to adjust the pH value to 6.5, washing, extracting, and drying under reduced pressure for 24 hours in vacuum to obtain the cross-linking agent.
The polymerization inhibitor is 2-tert-butyl hydroquinone; the organic solvent is toluene.
The esterification catalyst is N, N' -diisopropylcarbodiimide.
The photoinitiator is alpha, alpha-dimethoxy-alpha-phenylacetophenone and 2,4-dihydroxybenzophenone, and the weight ratio of the photoinitiator is 3:1 by mixing.
The silica gel is formed by mixing fine-pore silica gel and coarse-pore silica gel according to the weight ratio of 1:1; the particle size distribution of the silica gel is 230 meshes.
The preparation method of the drying agent comprises the following steps:
s, prefabricating a moisture-absorbing resin semi-finished product:
s1, taking acrylic acid, acrylamide, polyvinyl alcohol, a cross-linking agent, a photoinitiator, water and a plurality of sodium hydroxide solutions in parts by weight;
s2, adding acrylic acid into water according to the parts by weight, then adding a sodium hydroxide solution with the concentration of 50wt% to adjust the neutralization degree of the acrylic acid to be 75%, and then adding polyvinyl alcohol, acrylamide, a cross-linking agent and a photoinitiator to be uniformly mixed to obtain a mixed solution;
s3, fully reacting the mixed solution at 20 ℃ under stirring and ultraviolet radiation to obtain a reactant;
s4, adding 20 parts of 50wt% sodium hydroxide solution into the reactant, saponifying at 70 ℃ for 1 hour, filtering, and dehydrating with 95% ethanol to obtain a semi-finished product of the moisture absorption resin;
r, preparing moisture absorption type resin particles with a plurality of silica gels attached to the surfaces:
r1, taking 100 parts of a moisture-absorption resin semi-finished product, 1 part of micron-sized zeolite powder with the particle size of 30 mu m, 5 parts of silica gel and a plurality of polyoxyethylene-water solutions with the concentration of 1wt% for later use;
r2, dripping polyoxyethylene-water solution into the semi-finished product of the moisture absorption resin to ensure that the water content of the semi-finished product reaches 32wt%, and then adding micron-sized zeolite powder to be uniformly mixed to obtain a pre-formed particle;
r3, adding silica gel into the pre-granulated substance, and drying by adopting a drum dryer to obtain moisture absorption type resin particles with a plurality of silica gels attached to the surfaces;
p, packaging: and filling the moisture absorption resin particles into a desiccant bag, and sealing and storing to obtain the desiccant.
The irradiance of the ultraviolet radiation is 0.8W/m 2 @340nm, and the irradiation time is 30min; in the step S3, the stirring speed is 100r/min.
Example 3
A desiccant comprises a desiccant bag and a desiccant body accommodated in the desiccant bag, wherein the desiccant body comprises moisture absorption type resin and a plurality of silica gels attached to the surface of the moisture absorption type resin;
the moisture-absorbing resin is prepared from the following raw materials in parts by weight:
Figure SMS_5
the preparation method of each part of the cross-linking agent comprises the following steps:
a1, uniformly mixing 100 parts of polyethylene glycol and 0.20 part of polymerization inhibitor in parts by weight, adding 4 parts of acrylic acid, 0.5 part of esterification catalyst, 300 parts of organic solvent and 300 parts of cyclohexane, stirring, heating to 95 ℃, and preserving heat for 7 hours to obtain a crosslinked semi-finished product;
and A2, adding a sodium carbonate solution into the crosslinking semi-finished product to adjust the pH value to 7.5, washing, extracting, and drying under vacuum and reduced pressure for 24 hours to obtain the crosslinking agent.
The polymerization inhibitor is methyl hydroquinone; the organic solvent is toluene.
The esterification catalyst is 4-dimethylamino pyridine.
The photoinitiator is alpha, alpha-dimethoxy-alpha-phenylacetophenone and 2,4-dihydroxy benzophenone in a weight ratio of 3:5, mixing the components.
The silica gel is formed by mixing fine-pore silica gel and coarse-pore silica gel according to a weight ratio of 1:2; the particle size distribution of the silica gel is 460 meshes.
The preparation method of the drying agent comprises the following steps:
s, prefabricating a moisture-absorbing resin semi-finished product:
s1, taking acrylic acid, acrylamide, polyvinyl alcohol, a cross-linking agent, a photoinitiator, water and a plurality of sodium hydroxide solutions in parts by weight;
s2, adding acrylic acid into water according to the parts by weight, then adding a 60wt% sodium hydroxide solution to adjust the neutralization degree of the acrylic acid to 88%, and then adding polyvinyl alcohol, acrylamide, a cross-linking agent and a photoinitiator to uniformly mix to obtain a mixed solution;
s3, fully reacting the mixed solution at 35 ℃ under stirring and ultraviolet radiation to obtain a reactant;
s4, adding 30 parts of 60wt% sodium hydroxide solution into the reactant, performing saponification reaction for 3 hours at 90 ℃, filtering, and dehydrating with 95% ethanol to obtain a semi-finished product of the moisture-absorption resin;
r, preparing moisture absorption resin particles with a plurality of silica gels attached to the surfaces:
r1, taking 100 parts of a moisture-absorption resin semi-finished product, 5 parts of micron-sized zeolite powder with the particle size of 60 mu m, 20 parts of silica gel and a plurality of polyoxyethylene-water solutions with the concentration of 3wt% for later use;
r2, adding a polyoxyethylene-water solution into the semi-finished product of the moisture absorption resin dropwise until the water content reaches 50wt%, and then adding micron-sized zeolite powder to mix uniformly to obtain pre-formed particles;
r3, adding silica gel into the pre-granulated substance, and drying by adopting a drum dryer to obtain moisture absorption type resin particles with a plurality of silica gels attached to the surfaces;
p, packaging: and filling the moisture absorption type resin particles into a desiccant bag, and sealing and storing to obtain the desiccant.
The irradiance of the ultraviolet radiation is 1.4W/m 2 @340nm, and the irradiation time is 60min; in the step S3, the rotation speed of stirring is 200r/min.
Example 4
A desiccant comprises a desiccant material bag and a desiccant body accommodated in the desiccant material bag, wherein the desiccant body comprises moisture absorption type resin and a plurality of silica gels attached to the surface of the moisture absorption type resin;
the moisture-absorbing resin is prepared from the following raw materials in parts by weight:
Figure SMS_6
the preparation method of each part of the cross-linking agent comprises the following steps:
a1, uniformly mixing 100 parts of polyethylene glycol and 0.18 part of polymerization inhibitor in parts by weight, adding 3.6 parts of acrylic acid, 0.42 part of esterification catalyst, 150 parts of organic solvent and 230 parts of cyclohexane, stirring, heating to 88 ℃, and preserving heat for 5.8 hours to obtain a cross-linked semi-finished product;
and A2, adding a sodium carbonate solution into the crosslinking semi-finished product to adjust the pH value to 7.0, washing, extracting, and drying under vacuum and reduced pressure for 24 hours to obtain the crosslinking agent.
The polymerization inhibitor is 2-tert-butyl hydroquinone; the organic solvent is toluene.
The esterification catalyst is 4-dimethylamino pyridine.
The photoinitiator is alpha, alpha-dimethoxy-alpha-phenylacetophenone and 2,4-dihydroxy benzophenone in a weight ratio of 3:4, and mixing.
The silica gel is formed by mixing fine-pore silica gel and coarse-pore silica gel according to a weight ratio of 1; the particle size distribution of the silica gel is 270 meshes.
The preparation method of the drying agent comprises the following steps:
s, prefabricating a moisture-absorbing resin semi-finished product:
s1, taking acrylic acid, acrylamide, polyvinyl alcohol, a cross-linking agent, a photoinitiator, water and a plurality of sodium hydroxide solutions in parts by weight;
s2, adding acrylic acid into water according to parts by weight, then adding a sodium hydroxide solution with the concentration of 57wt% to adjust the neutralization degree of the acrylic acid to 78%, and then adding polyvinyl alcohol, acrylamide, a cross-linking agent and a photoinitiator to be uniformly mixed to obtain a mixed solution;
s3, fully reacting the mixed solution at 28 ℃ under stirring and ultraviolet radiation to obtain a reactant;
s4, adding 27 parts of 57wt% sodium hydroxide solution into the reactant, saponifying at 85 ℃ for 1.5 hours, filtering, and dehydrating with 95% ethanol to obtain a semi-finished product of the moisture absorption resin;
r, preparing moisture absorption type resin particles with a plurality of silica gels attached to the surfaces:
r1, taking 100 parts of a moisture-absorption resin semi-finished product, 3 parts of micron-sized zeolite powder with the particle size of 50 mu m, 15 parts of silica gel and a plurality of polyoxyethylene-water solutions with the concentration of 1.5wt% for later use;
r2, dripping polyoxyethylene-water solution into the semi-finished product of the moisture absorption resin to ensure that the water content of the semi-finished product reaches 43wt%, and then adding micron-sized zeolite powder to be uniformly mixed to obtain a pre-formed particle;
r3, adding silica gel into the pre-granulated substance, and drying by adopting a drum dryer to obtain moisture absorption type resin particles with a plurality of silica gels attached to the surfaces;
p, packaging: and filling the moisture absorption type resin particles into a desiccant bag, and sealing and storing to obtain the desiccant.
The irradiance of the ultraviolet radiation is 1.2W/m 2 @340nm, and the irradiation time is 45min; in the step S3, the rotating speed of stirring is 180r/min.
Comparative example 1
This comparative example differs from example 1 in that:
silica gel is not attached to the surface of the moisture-absorbing resin, and the moisture-absorbing resin and the silica gel are dispersed and filled into a desiccant bag;
in the preparation method of the drying agent, the steps R and P are changed into:
step R, infrared drying and crushing are carried out on the semi-finished product of the moisture-absorbing resin to obtain moisture-absorbing resin powder; namely, it is not necessary to prepare moisture-absorbent resin particles having a plurality of silica gels attached to the surface thereof;
step P, packaging: and mixing the moisture-absorbing resin powder and silica gel according to the weight part ratio of 100 to 10, filling the mixture into a desiccant package, and sealing and storing the desiccant package to obtain the desiccant.
Comparative example 2
This comparative example differs from example 1 in that:
silica gel is not attached to the surface of the moisture absorption resin, and the moisture absorption resin and the silica gel are dispersedly filled into a desiccant material bag;
in the preparation method of the drying agent, the steps R3 and P are changed into:
step R3, silica gel is not added, and the pre-granulated substance is directly dried by a drum dryer to obtain moisture absorption type resin particles;
step P, packaging: and mixing the moisture absorption resin particles and silica gel according to the weight ratio of 100 to 10, filling the mixture into a desiccant bag, and sealing and storing the desiccant bag to obtain the desiccant.
Comparative example 3
This comparative example differs from example 1 in that:
the cross-linking agent adopts N' N-methylene bisacrylamide which is commercially available.
Comparative example 4
This comparative example differs from example 1 in that:
and (4) carrying out no saponification reaction in the step S4, namely filtering the reactant in the step S3 directly and dehydrating the reactant with 95% ethanol to obtain a semi-finished product of the moisture absorption type resin.
Comparative example 5
This comparative example differs from example 1 in that:
the desiccant body is of moisture-absorbing resin, i.e., the desiccant body does not contain silica gel.
In the step R3, the pre-granulated substance is dried directly by a drum dryer without adding silica gel, to obtain the moisture-absorbent resin particles having a plurality of silica gels attached to the surface thereof.
Comparative example 6
This comparative example differs from example 1 in that:
the desiccant body is silica gel, namely the desiccant body does not contain moisture-absorption resin; the silica gel is formed by mixing fine-pore silica gel and coarse-pore silica gel according to a weight ratio of 1.
Performance testing
Taking the drier bodies of the examples 1-4 and the comparative examples 1-6, respectively taking 0.3g of the dosage, and respectively testing the saturated moisture absorption rate and the moisture absorption rate; the test method is as follows:
saturated moisture absorption rate: testing at 25 ℃ and RH =100% until the desiccant body is continuously weighed for 1h twice and does not exceed 1mg, and calculating by referring to GB T6284-2006 Standard of general method drying decrement method for measuring moisture in chemical products;
moisture absorption rate: testing by referring to GB T34709-2017 silica gel general test method 3.7.1 static adsorption method under the conditions of RH =20%, RH =50% and RH =90% respectively;
the test results are shown in table 1 below:
TABLE 1
Figure SMS_7
/>
Figure SMS_8
As can be seen from table 1 above, in the desiccant of the present invention, the desiccant body is attached with a plurality of silica gels on the surface of the moisture-absorbing resin, and the silica gels are used to absorb moisture in the air, so that the silica gels absorb water and condense into liquid water, which is more favorable for the moisture-absorbing resin to absorb the liquid water in the silica gels, thereby increasing the overall water absorption capacity of the desiccant and increasing the saturated water absorption of the desiccant. Compared with the comparative examples 1-2, the surface of the moisture absorption resin of the example 1 is adhered with silica gel, the moisture absorption resin is granular, and the moisture absorption rate is obviously increased; compared with the comparative example 3, the special cross-linking agent of the example 1 is more beneficial to promoting the moisture absorption effect of the moisture absorption type resin combined with the silica gel; compared with the comparative example 4, the step S4 of the moisture-absorption resin of the example 1 is subjected to saponification reaction, so that the moisture absorption rate of the whole drying agent body is obviously improved; compared with the comparative example 5, the moisture absorption effect is more obvious when the moisture absorption type resin with a plurality of silica gels attached to the surface is adopted in the example 1, and the high-efficiency moisture absorption effect is difficult to be exerted because the moisture absorption capacity of the moisture absorption type resin is lower if only the moisture absorption type resin is adopted; compared with the example 1, the desiccant body prepared by only mixing the fine-pore silica gel and the coarse-pore silica gel in the comparative example 6 has obviously insufficient moisture absorption rate and is easy to saturate, and the cost is not saved in transportation environments such as sea transportation, freight transportation and the like.
The above-described embodiments are preferred implementations of the present invention, and the present invention can be implemented in other ways without departing from the spirit of the present invention.

Claims (1)

1. A desiccant, characterized by: the desiccant material bag type drying machine comprises a desiccant material bag and a desiccant body accommodated in the desiccant material bag, wherein the desiccant body comprises moisture absorption type resin and a plurality of silica gels attached to the surface of the moisture absorption type resin; the moisture-absorbing resin is prepared from the following raw materials in parts by weight:
Figure FDA0004112159570000011
the preparation method of each part of the cross-linking agent comprises the following steps:
a1, uniformly mixing 100 parts of polyethylene glycol and 0.15-0.20 part of polymerization inhibitor according to parts by weight, then adding 3-4 parts of acrylic acid, 0.4-0.5 part of esterification catalyst, 100-300 parts of organic solvent and 150-300 parts of cyclohexane, stirring, heating to 85-95 ℃, and preserving heat for 5-7 hours to obtain a crosslinked semi-finished product;
a2, adding a sodium carbonate solution into the cross-linking semi-finished product to adjust the pH value to 6.5-7.5, washing, extracting, and drying under reduced pressure in vacuum for 24 hours to obtain the cross-linking agent;
the silica gel is fine-pore silica gel and/or coarse-pore silica gel; the particle size distribution of the silica gel is 230-460 meshes; the weight ratio of the moisture-absorbing resin to the silica gel is (100);
the preparation method of the drying agent comprises the following steps:
s, prefabricating a moisture-absorbing resin semi-finished product:
s1, taking acrylic acid, acrylamide, polyvinyl alcohol, a cross-linking agent, a photoinitiator, water and a plurality of sodium hydroxide solutions in parts by weight;
s2, adding acrylic acid into water according to the parts by weight, then adding a sodium hydroxide solution to adjust the neutralization degree of the acrylic acid to be 75-88%, and then adding polyvinyl alcohol, acrylamide, a cross-linking agent and a photoinitiator to be uniformly mixed to obtain a mixed solution;
s3, fully reacting the mixed solution at the temperature of 20-35 ℃ under stirring and ultraviolet radiation to obtain a reactant;
s4, adding a sodium hydroxide solution into the reactant, performing saponification reaction for 1-3h at 70-90 ℃, filtering, and dehydrating with 95% ethanol to obtain a semi-finished product of the moisture absorption type resin;
r, preparing moisture absorption type resin particles with a plurality of silica gels attached to the surfaces;
p, packaging: filling moisture absorption type resin particles into a desiccant bag, and sealing and storing to obtain the desiccant;
the polymerization inhibitor is methyl hydroquinone or 2-tert-butyl hydroquinone; the organic solvent is toluene;
the esterification catalyst is at least one of dicyclohexylcarbodiimide, N' -diisopropylcarbodiimide and 4-dimethylaminopyridine;
the photoinitiator is alpha, alpha-dimethoxy-alpha-phenylacetophenone and 2,4-dihydroxy benzophenone in a weight ratio of 3:1-5, mixing; the concentration of the sodium hydroxide solution is 50-60wt%;
the irradiance of the ultraviolet radiation is 0.8-1.4W/m 2 @340nm, and the irradiation time is 30-60min; in the step S3, the stirring speed is 100-200r/min;
the preparation method of the moisture absorption type resin particles with a plurality of silica gels attached to the surfaces comprises the following steps:
r1, taking 100 parts of moisture-absorbing resin semi-finished product, 1-5 parts of micron-sized zeolite powder with the particle size of 30-60 mu m, 5-20 parts of silica gel and a plurality of polyoxyethylene-water solutions with the concentration of 1-3wt% for later use;
r2, dripping polyoxyethylene-water solution into the semi-finished product of the moisture absorption resin to ensure that the water content of the semi-finished product reaches 32-50wt%, then adding micron-sized zeolite powder, and uniformly mixing to obtain a pre-formed granule;
r3, adding silica gel into the pre-granulated substance, and drying by adopting a drum dryer to obtain moisture absorption type resin particles with a plurality of silica gels attached to the surfaces;
the concentration of the polyoxyethylene-water solution is 1-3wt%; the particle size of the micron-sized zeolite powder is 30-60 mu m.
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