Micro-space intelligent shaping solid desiccant and preparation method thereof

Abstract

The application belongs to the technical field of desiccant preparation, and particularly relates to a micro-space intelligent shaping solid desiccant and a preparation method thereof. The micro-space intelligent shaping solid desiccant is prepared from the following raw materials in percentage by weight: 20-35% of plastic particles, 15-20% of silicon dioxide, 20-35% of calcium carbonate and 20-38% of sodium silicoaluminate. The application mixes PP plastic particles, ABS plastic particles, silicon dioxide, calcium carbonate and sodium silicoaluminate in a certain proportion, and utilizes injection molding technology to prepare a high-performance desiccant with customized shape, size and thickness. The desiccant not only has excellent moisture absorption performance, but also has a smooth surface and does not need secondary packaging, and can be directly applied to various micro spaces requiring humidity control or used as a component of a product.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of desiccant preparation, and particularly relates to a micro-space intelligent shaping solid desiccant and a preparation method thereof. BACKGROUND

[0002] In many fields such as electronic products (such as electric toothbrushes), precision instruments (mobile phones), food and drug packaging, cultural relic preservation, etc., the control of micro-environment humidity is extremely high, especially in extremely limited space, the application of traditional desiccants is severely limited. The mainstream desiccants on the market include calcium chloride desiccant, silica gel desiccant, magnesium chloride desiccant, molecular sieve desiccant, calcium oxide desiccant and montmorillonite desiccant, etc. These desiccants have their own characteristics, but they all have two common problems in application.

[0003] 1. Dust problem: all the above-mentioned desiccants, whether based on chemical reaction to absorb moisture (such as calcium chloride and calcium oxide) or physical adsorption (such as silica gel and molecular sieve), are prone to produce dust in the raw materials themselves or in the use process. Dust not only pollutes the protected objects, but also may pose a threat to human health, especially when used in closed or small spaces, the problem is particularly prominent. Therefore, these desiccants usually need additional secondary packaging in actual application, that is, the desiccant raw materials are sealed and wrapped with packaging film to prevent dust leakage. This not only increases the production cost, but also limits the application of desiccants in some occasions where the volume and weight of the packaging are strictly required.

[0004] 2. Size and shape limitation: the size of existing desiccant products is usually large (length or diameter greater than 1 cm), and the thickness exceeds 2 mm. Such volume and thickness make them difficult to adapt to the humidity control requirements of small spaces (such as small gaps inside electronic devices, micro-sensor packaging, etc.). This size limitation seriously hinders the wide application of desiccants in high-tech products, micro-medical devices and other fields, and cannot meet the requirements of modern industry for miniaturization and integration.

[0005] In the internal of precision electronic equipment such as electric toothbrush, desiccant not only needs to have high efficient moisture absorption capacity, but also needs to consider structural strength, wear resistance, chemical stability and the characteristics of adapting to narrow space. Therefore, in order to overcome the above-mentioned defects, a micro-space intelligent shaping solid desiccant needs to be developed, which can be flexibly made into various shapes according to the specific requirements of the space to be dried, and even directly integrated into the customer's product components, thereby greatly expanding the application range of desiccants. SUMMARY

[0006] The purpose of the present application is to provide a micro-space intelligent shaping solid desiccant and a preparation method thereof, which has excellent plasticity while maintaining high efficient moisture absorption performance.

[0007] A micro-space intelligent shaping solid desiccant, raw materials for preparing the micro-space intelligent shaping solid desiccant by weight percentage are as follows: plastic particles 20%-35%, silicon dioxide 15%-20%, calcium carbonate 20%-35%, sodium silicoaluminate 20%-38%.

[0008] In some preferred embodiments, raw materials for preparing the micro-space intelligent shaping solid desiccant by weight percentage are as follows: plastic particles 25%-30%, silicon dioxide 17%-19%, calcium carbonate 20%-28%, sodium silicoaluminate 20%-30%.

[0009] In some preferred embodiments, the micro-space intelligent shaping solid desiccant further comprises activated carbon and dye, and the activated carbon and the dye are added in an amount of 10%-15% and 0.1%-0.5% of the mass of the micro-space intelligent shaping solid desiccant, respectively.

[0010] The plastic particles comprise PP and ABS.

[0011] The mass ratio of the PP and the ABS is 1: (0.5-2); further preferably, 1:1.

[0012] The PP is homopolymer PP, and the melt index at 230℃ is 8-13 g / 10 min, the density is 0.89-0.92 g / cm 3 , and the tensile yield stress is ≥33 MPa.

[0013] The PP is purchased from Exxon Mobil, PP1304E5.

[0014] The ABS has a melt index at 220℃ of 2-3 g / 10 min, a density of 1.03-1.07 g / cm 3 , and a 1 / 4" IZOD impact strength of ≥6.5 ft·lb / in.

[0015] The PP is purchased from Quaker Chemical, PA-747R.

[0016] The specific PP plastic particles are selected as the basic carrier of the desiccant, and are blended with specific ABS plastic particles, which can improve the structural strength of the desiccant while maintaining its moisture absorption performance, thereby ensuring its integrity. This may be due to the synergistic effect between the two types of plastic particles. The PP plastic particles provide a solid foundation for the desiccant with their lightweight, high rigidity, and good processing performance. The density of the PP plastic particles is between 0.89 g / cm³ and 0.92 g / cm³, ensuring that the desiccant is neither too heavy to affect the overall weight of the electric toothbrush nor lacks sufficient structural support. Moreover, the PP plastic particles have stable chemical properties, meaning they will not react adversely with other materials in the complex environment of the electric toothbrush, thereby ensuring the long-term effectiveness and safety of the desiccant. The addition of ABS plastic particles further enhances the structural strength of the desiccant, significantly increasing the overall toughness of the desiccant after blending with the PP plastic particles. This enhancement is crucial for the internal components of the electric toothbrush, as the electric toothbrush undergoes frequent vibrations and friction during use. The desiccant needs to maintain its integrity and moisture absorption performance to continuously protect the internal components of the electric toothbrush from moisture. Therefore, the high rigidity of the PP plastic particles provides a stable structural framework for the desiccant, while the high impact strength and wear resistance of the ABS plastic particles enhance the toughness of this framework. The synergistic effect of the two types of plastic particles enables the desiccant to maintain a stable structural form within the electric toothbrush while resisting the impact of vibrations and friction, thereby ensuring the long-term stability and reliability of the electric toothbrush. This allows the desiccant to continuously perform its moisture absorption and protection functions in a complex environment. However, the amount of plastic particles should not be excessive. When the total amount of plastic particles exceeds 35%, on the one hand, the excess addition of PP and ABS plastic particles, which do not have moisture absorption functions, will occupy the internal space of the desiccant, reducing the proportion of effective moisture absorption components (such as fumed silica and sodium aluminosilicate), resulting in a significant decrease in the moisture absorption capacity of the desiccant. On the other hand, the high cost of plastic particles will increase the production cost of the desiccant, reducing its market competitiveness.

[0017] In some preferred embodiments, the ABS can also consider using other injection-moldable wear-resistant materials, such as polyamide plastics, etc.

[0018] The silica is fumed silica with a particle size of 300-400 mesh.

[0019] The fumed silica is purchased from Shandong Casone New Materials Co., Ltd.

[0020] The particle size of the calcium carbonate is 100-150 mesh.

[0021] The calcium carbonate is purchased from Shijiazhuang Hualang Mineral Products Trade Co., Ltd.

[0022] The particle size of the sodium aluminosilicate is 150-250 mesh.

[0023] The sodium aluminosilicate is purchased from Guangdong Aosimann Biological Technology Co., Ltd.

[0024] The three different particle sizes of inorganic particles are compounded, which not only improves the moisture absorption effect of the desiccant, but also improves the moisture absorption stability. This may be because the three inorganic particles have a synergistic effect. The fumed silica and sodium aluminosilicate together improve the moisture absorption efficiency of the desiccant, so that the desiccant can more quickly adsorb and lock moisture, and at the same time maintain a dry environment inside the electric toothbrush to help the desiccant maintain stable moisture absorption performance for a long time, effectively preventing moisture from corroding electronic components. The fumed silica also enhances the structural stability of the desiccant, so that it can maintain stable moisture absorption performance and not deform under harsh conditions such as high temperature and high humidity. At the same time, the filling effect of calcium carbonate further improves the physical strength of the desiccant. Moreover, as a filler, calcium carbonate not only adjusts the hardness of the desiccant, making it better fit inside the electric toothbrush components, but also reduces production costs and improves the economy of the desiccant. In addition, the particle sizes of the selected inorganic particles are different, which can further improve the strength and toughness of the desiccant. The three different particle sizes of inorganic particles in the plastic particle matrix can form a particle size complementary effect. Larger nanoparticles can act as stress concentration points to initiate crazing or cavitation effects, while smaller nanoparticles can fill these defects and terminate crack propagation. This particle size complementary effect helps to form a more dense toughening network and improve the overall performance of the desiccant.

[0025] However, the addition amount of both silica and calcium carbonate should not be too large. Since fumed silica has a small density and strong interparticle interaction, when the addition amount of fumed silica exceeds 20%, not only will it be difficult to compact the desiccant mixture during molding, making it impossible to form a stable structure, but also the desiccant will be more prone to breakage when subjected to external forces, reducing its service life and performance stability. When the addition amount of calcium carbonate exceeds 35%, similar to fumed silica, it will not only make it difficult to compact the desiccant mixture during molding, making it impossible to form a stable structure, but also reduce the toughness of the desiccant, making it more prone to breakage when subjected to external forces. In addition, although calcium carbonate has some moisture absorption capacity, its effect is far inferior to that of high-efficiency moisture absorption materials such as fumed silica and sodium aluminosilicate. Therefore, excessive addition of calcium carbonate will further reduce the moisture absorption performance of the desiccant.

[0026] In some preferred embodiments, the fumed silica can be replaced by other nanomaterials with moisture absorption properties, such as nano-aluminum oxide, nano-calcium oxide, etc.

[0027] The activated carbon is coal-based activated carbon with a particle size of 8-20 mesh and a phenol adsorption capacity ≥160 mg / g.

[0028] In some preferred schemes, the activated carbon is purchased from Zhejiang Zhe-wolf activated carbon Co., Ltd.

[0029] The dye is commercially available, and is not specifically limited in the present application.

[0030] The preparation method of the micro-space intelligent shaping solid desiccant comprises the following steps:

[0031] S1, desiccant mixing: all raw materials are put into the reaction kettle according to the proportion, the stirring speed is set to 55-65 r / min, the temperature is set to 215-225℃, after the plastic particles are completely melted, the stirring speed is adjusted to 195-205 r / min, and the stirring time is ≥30 min;

[0032] S2, adjust the temperature to 215-225℃, the rotating speed is 115-125 r / min, open the air outlet valve, so that the reaction kettle is maintained at standard atmospheric pressure, then open the bottom air inlet valve of the reaction kettle, slowly pass carbon dioxide gas into the reaction kettle, and the aeration time is 30-60 min;

[0033] S3, the molten uniform material is sent from the reaction kettle into the hopper of the screw extruder, the size of the desiccant is determined by the die of the extruder, extrusion, granulation, cooling, dehydration and drying are carried out, and the desiccant is obtained.

[0034] In the preparation process of the desiccant, carbon dioxide gas is slowly passed into the reaction kettle at standard atmospheric pressure, and the carbon dioxide gas forms small bubbles in the molten material, which helps to further uniformly mix the material and improve the microstructure of the desiccant, thereby improving the performance of the desiccant.

[0035] Compared with the prior art, the advantages and beneficial effects of the present application are:

[0036] 1. The present application provides a micro-space intelligent shaping solid desiccant, which is prepared by mixing PP plastic particles with ABS plastic particles, fumed silica, calcium carbonate and sodium aluminosilicate in a certain proportion, and using injection molding technology to prepare a high-performance desiccant with customizable shape, size and thickness. The desiccant not only has excellent moisture absorption performance, but also has a smooth surface and does not need secondary packaging, and can be directly applied to various small spaces that need humidity control or as product components.

[0037] 2. The present application adopts special proportioning of moisture absorption materials and molding technology, so that the desiccant not only maintains high-efficiency moisture absorption performance, but also has excellent plasticity. By accurately controlling the molding process, the desiccant can be shaped into various shapes and sizes to meet different needs from small micro-spaces of a few millimeters to larger size equipment. This customization capability enables the desiccant to seamlessly integrate into product design without the need for additional secondary packaging, simplifying the production process and reducing costs.

[0038] 3. The desiccant of the present application does not change significantly in shape or structure after absorbing moisture, keeping the surface clean and avoiding the pollution to the product or environment caused by the expansion or dust of the traditional desiccant. This feature makes the desiccant particularly suitable for applications with extremely high requirements for cleanliness and stability, such as electronic products, precision instruments, food and drug packaging, etc.

[0039] 4. The present application selects specific PP plastic particles as the basic carrier of the desiccant, and blends with specific ABS plastic particles, which can improve the structural strength of the desiccant while maintaining its moisture absorption performance, thereby ensuring its integrity.

[0040] 5. The present application selects three different particle sizes of inorganic particles for compounding, which can not only improve the moisture absorption effect of the desiccant, but also improve the moisture absorption stability.

[0041] 6. In the preparation process of the desiccant, carbon dioxide gas is slowly introduced into the reaction kettle at standard atmospheric pressure, and the carbon dioxide gas forms small bubbles in the molten material, which helps to further mix the material and improve the microstructure of the desiccant, thereby improving the performance of the desiccant. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0043] PP is homopolymer PP, with a melt index of 8-13 g / 10 min at 230℃ and a density of 0.89-0.92 g / cm 3 , tensile yield stress ≥ 33 MPa, purchased from Exxon Mobil, PP1304E5.

[0044] ABS has a melt index of 2-3 g / 10 min at 220℃ and a density of 1.03-1.07 g / cm 3 , 1 / 4" IZOD impact strength ≥ 6.5 ft·lb / in, purchased from Taiwan's Quaker, PA-747R.

[0045] Fumed silica, particle size 300-400 mesh, purchased from Shandong Casone New Material Co., Ltd.

[0046] Calcium carbonate, particle size 100-150 mesh, purchased from Shijiazhuang Hualang Mineral Products Trading Co., Ltd.

[0047] Sodium aluminosilicate, particle size of 200 mesh, purchased from Guangdong Ousiman Biotechnology Co., Ltd.

[0048] Example 1

[0049] The micro-space intelligent shaping solid desiccant is prepared from the following raw materials in percentage by weight: 25% of plastic particles, 19% of fumed silica, 27% of calcium carbonate, and 29% of sodium aluminosilicate.

[0050] The plastic particles are PP and ABS, and the mass ratio is 1:1.

[0051] The preparation method of the micro-space intelligent shaping solid desiccant comprises the following steps:

[0052] S1, desiccant mixing: all raw materials are put into the reaction kettle according to the proportion, the stirring speed is set to 60 r / min, and the temperature is set to 220℃, after the plastic particles are completely melted, the stirring speed is adjusted to 200 r / min, and the stirring time is 40 min;

[0053] S2, the temperature is adjusted to 220℃, the stirring speed is 120 r / min, the gas outlet valve is opened, so that the reaction kettle is maintained at standard atmospheric pressure, then the gas inlet valve at the bottom of the reaction kettle is opened, and carbon dioxide gas is slowly introduced into the reaction kettle, and the aeration time is 50 min;

[0054] S3, the molten and uniform material is sent from the reaction kettle to the hopper of the screw extruder, the size of the desiccant is determined by the die of the extruder, and the desiccant is extruded, granulated, cooled, dehydrated, and dried.

[0055] Example 2

[0056] The difference between this example and example 1 is that the micro-space intelligent shaping solid desiccant is prepared from the following raw materials in percentage by weight: 30% of plastic particles, 17% of fumed silica, 27% of calcium carbonate, and 26% of sodium aluminosilicate.

[0057] Example 3

[0058] The difference between this example and example 1 is that the plastic particles are PP and PA6, and the mass ratio is 1:1.

[0059] The density of the PA6 is 1.08 g / cm 3 , and the notched impact strength of the simply supported beam is 80 kJ / m 2 , purchased from Nanjing Delong Engineering Plastics Co., Ltd., B801.

[0060] Example 4

[0061] The difference between this embodiment and embodiment 1 is that the micro-space intelligent shaping solid desiccant is prepared from the following raw materials by weight percentage: plastic particles 25%, alumina 19%, calcium carbonate 27%, and sodium aluminosilicate 29%. The alumina has a particle size of 300-400 mesh.

[0062] Example 5

[0063] The difference between this embodiment and embodiment 1 is that the micro-space intelligent shaping solid desiccant further comprises activated carbon and dye, and the activated carbon and dye are added in an amount of 10% and 0.1% of the mass of the micro-space intelligent shaping solid desiccant, respectively. The dye is a yellow color masterbatch, which is purchased from Shanghai Xiceng Plastic Products Co., Ltd.

[0064] Comparative Example 1

[0065] The difference between this comparative example and embodiment 1 is that the micro-space intelligent shaping solid desiccant is prepared from the following raw materials by weight percentage: plastic particles 35%, fumed silica 12%, calcium carbonate 23%, and sodium aluminosilicate 30%.

[0066] Comparative Example 2

[0067] The difference between this comparative example and embodiment 1 is that the micro-space intelligent shaping solid desiccant is prepared from the following raw materials by weight percentage: plastic particles 15%, fumed silica 24%, calcium carbonate 30%, and sodium aluminosilicate 31%.

[0068] Comparative Example 3

[0069] The difference between this comparative example and embodiment 1 is that the micro-space intelligent shaping solid desiccant is prepared from the following raw materials by weight percentage: plastic particles 10%, fumed silica 26%, calcium carbonate 30%, and sodium aluminosilicate 34%.

[0070] Comparative Example 4

[0071] The difference between this comparative example and embodiment 1 is that the micro-space intelligent shaping solid desiccant is prepared from the following raw materials by weight percentage: plastic particles 25%, fumed silica 15%, calcium carbonate 40%, and sodium aluminosilicate 20%.

[0072] Comparative Example 5

[0073] The difference between this comparative example and embodiment 1 is that the plastic particles are PP.

[0074] Comparative Example 6

[0075] The difference between this comparative example and embodiment 1 is that the fumed silica has a particle size of 100-200 mesh, which is purchased from Shandong Casone New Material Co., Ltd.

[0076] Comparative Example 7

[0077] The difference between the present comparative example and Example 1 is that the preparation method of the micro-space intelligent shaping solid desiccant comprises the following steps:

[0078] S1, desiccant mixing: all raw materials are put into the reaction kettle according to the proportion, the stirring speed is set to 55-65 r / min, and the temperature is set to 215-225℃, after the plastic particles are completely melted, the stirring speed is adjusted to 195-205 r / min, and the stirring time is 60 min;

[0079] S2, the molten uniform material is sent from the reaction kettle to the hopper of the screw extruder, the size of the desiccant is determined by the die of the extruder, and then the desiccant is extruded, granulated, cooled, dehydrated and dried.

[0080] Performance test

[0081] According to GB / T 41897-2022 "Quality Requirements for Food Desiccants", the hygroscopicity of the prepared desiccant after being placed at 28℃, 90%RH for 7 days is tested, the size of the desiccant is 15*12*5mm, and the state of the sample before and after hygroscopicity is observed. Each group of samples tests 3 groups of parallel samples. The results are shown in Table 1.

[0082]

[0083] According to statistics, the micro-space intelligent shaping solid desiccant prepared in Examples 1-5 has small sample size but good forming effect, high hygroscopicity, and the sample remains intact after hygroscopicity, indicating good hygroscopic stability. The addition amount of silicon dioxide in Comparative Example 1 is too small, the addition amount of plastic particles in Comparative Examples 2 and 3 is too small, the addition amount of silicon dioxide is too large, the amount of calcium carbonate in Comparative Example 4 is excessive, the addition amount of silicon dioxide and sodium aluminosilicate is too small, and Comparative Example 5 does not add ABS, Comparative Example 6 has too large particle size of silicon dioxide, and Comparative Example 7 does not pass carbon dioxide gas during melting. The desiccants prepared by the above methods have poor forming effect, hygroscopic effect and hygroscopic stability. Therefore, the micro-space intelligent shaping solid desiccant prepared by the raw materials and method described in the present application not only has excellent hygroscopicity, but also has good hygroscopic stability, and can be shaped into various shapes and sizes, meeting the different needs of micro-space from a few millimeters to larger size equipment, especially suitable for application scenarios with extremely high cleanliness and stability requirements, such as electronic products, precision instruments, food and drug packaging, etc.

[0084] The above is a preferred embodiment of the present application. It should be noted that for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, which should also be considered within the scope of protection of the present application.

Claims

1. A micro-space intelligent shaping solid desiccant, characterized in that, The raw materials for its preparation, by weight percentage, are: 20%-35% plastic particles, 15%-20% silicon dioxide, 20%-35% calcium carbonate, and 20%-38% sodium aluminosilicate; The plastic particles include PP and ABS; the PP is homopolymer PP, with a melt index of 8-13 g / 10 min at 230℃ and a density of 0.89-0.92 g / cm³. 3 The tensile yield stress is ≥33MPa; the melt flow index of ABS at 220℃ is 2-3g / 10min, and the density is 1.03-1.07g / cm³. 3 1 / 4" IZOD impact strength ≥ 6.5 ft·lb / in; The preparation method of micro-space intelligent shaping solid desiccant includes: S1. Desiccant mixing: Add all raw materials into the reactor according to the ratio, set the speed to 55-65r / min and the temperature to 215-225℃ and stir until the plastic particles are completely melted. Then adjust the speed to 195-205r / min and continue stirring for ≥30min. S2. Adjust the temperature to 215-225℃ and the rotation speed to 115-125r / min. Open the gas outlet valve to keep the reactor under standard atmospheric pressure. Then open the gas inlet valve at the bottom of the reactor to slowly introduce carbon dioxide gas into the reactor for 30-60 minutes. S3. The uniformly molten material is fed from the reactor into the hopper of the screw extruder. The size of the desiccant is customized by the die of the extruder. The material is then extruded, granulated, cooled, dehydrated, and dried to obtain the final product.

2. The micro-space intelligent shaping solid desiccant according to claim 1, characterized in that, The micro-space intelligent shaping solid desiccant is prepared by the following raw materials by weight percentage: 25%-30% plastic particles, 17%-19% silicon dioxide, 20%-28% calcium carbonate, and 20%-30% sodium aluminosilicate.

3. The micro-space intelligent shaping solid desiccant according to claim 1, characterized in that, The mass ratio of PP to ABS is 1:(0.5-2).

4. The micro-space intelligent shaping solid desiccant according to claim 1, characterized in that, The silica is fumed silica with a particle size of 300-400 mesh.

5. The micro-space intelligent shaping solid desiccant according to claim 1, characterized in that, The calcium carbonate has an average particle size of 20 nm and a specific surface area of ​​30-60 m². 2 / g.

6. The micro-space intelligent shaping solid desiccant according to claim 1, characterized in that, The sodium aluminosilicate has a particle size of 150-250 mesh.

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