Baking soda assisted steam explosion modified corncob plant litter and method of making same

Abstract

The application discloses a baking soda assisted steam explosion modified corncob plant cat litter and a preparation method thereof, and belongs to the technical field of pet chemicals. The plant cat litter comprises 27-33 parts of modified corncob powder, 12-18 parts of cassava powder, 0.4-0.6 parts of superabsorbent resin, 2-6 parts of bamboo leaf powder, 0.3-0.9 parts of vegetable oil and 3-4 parts of guar gum. The modified corncob powder is obtained by pre-soaking treatment and steam explosion treatment of baking soda solution. The final plant cat litter has a water absorption rate of 826%, a clumping strength of 93.47%, a dust rate of 0.28% and a deodorization rate of 99.98%, and has significant advantages in terms of flushing performance.

Description

Technical Field

[0001] This invention relates to the field of pet chemical products technology, specifically to a method and product for preparing plant-based cat litter using a core process of modifying corn cobs with baking soda solution-assisted pretreatment combined with steam explosion technology, and compounding cassava flour, superabsorbent resin, bamboo leaf powder, vegetable oil and guar gum. Background Technology

[0002] Cat litter is one of the most consumed categories in the pet supplies market. Currently, the mainstream products on the market include bentonite cat litter, silica gel cat litter, tofu cat litter, and plant-based cat litter. Bentonite cat litter has good clumping properties but produces a lot of dust and is non-biodegradable; silica gel cat litter has strong odor absorption but is expensive and insoluble in water; tofu cat litter is biodegradable, but its water absorption rate and clumping strength are insufficient; plant-based wood-based cat litter has a looser texture and a higher dust content. Corn cobs are an agricultural waste with extremely abundant production in my country. Their natural structure has a certain degree of porosity, making them a promising candidate for cat litter production. However, using corn cobs that have only been crushed to produce cat litter results in poor water absorption and clumping due to the presence of a waxy layer on the surface, which makes them highly hydrophobic. Summary of the Invention

[0003] This invention aims to provide a sodium bicarbonate-assisted steam explosion modified corn cob plant cat litter and its preparation method, in order to solve the problems of slow water absorption rate, insufficient clumping strength, high dust content and limited deodorization effect of existing plant cat litter, while realizing the high-value utilization of agricultural waste corn cobs.

[0004] To achieve the above objectives, the technical solution provided by the present invention is as follows: A sodium bicarbonate-assisted steam explosion modified corn cob plant cat litter comprises the following raw materials in parts by weight: 27-33 parts modified corn cob powder, 12-18 parts cassava powder, 0.4-0.6 parts superabsorbent polymer (SAP) resin, 2-6 parts bamboo leaf powder, 0.3-0.9 parts vegetable oil, and 3-4 parts guar gum.

[0005] The modified corn cob powder is prepared by a combination of pre-impregnation with baking soda solution and steam explosion. The specific preparation method is as follows: Place the corn cob kernels in a container, prepare a sodium bicarbonate (NaHCO3) aqueous solution, and spray it evenly on the surface of the corn cob kernels to allow the solution to fully penetrate into the kernels. Let it stand to complete the pre-soaking. Preferably, the corn cob particle size is 4-6 mm.

[0006] Preferably, the baking soda solution is a 1.6% (w / w) aqueous solution, and the amount of baking soda solution used is 50% (w / w) of the dry weight of the corn cob particles. The baking soda solution is weakly alkaline, which can saponify the waxy layer on the surface of the corn cob during the pre-soaking stage, remove the hydrophobic barrier, and allow subsequent steam to penetrate the interior of the particles more evenly. At the same time, the weakly alkaline environment helps to hydrolyze the acetyl groups of hemicellulose, forming an acidic microenvironment in the bursting chamber, catalyzing the breakage of hemicellulose glycosidic bonds, making the bursting modification effect more thorough, and significantly improving the water absorption rate and clumping strength of the corn cob.

[0007] The pre-soaked corn cob particles are loaded into the explosion chamber of a steam explosion machine, sealed, and saturated steam is introduced to stabilize the pressure. After the pressure stabilization is completed, the pressure relief valve is opened instantly to complete the explosion. The exploded corn cob particles are rinsed with warm water 2-3 times to remove free alkali and water-soluble degradation products. They are then dried in an oven, pulverized by a pulverizer, and passed through a 60-mesh sieve to obtain modified corn cob powder.

[0008] Furthermore, saturated steam was introduced to increase the pressure to 1.4 MPa, and the pressure was maintained at this level for 190 seconds.

[0009] The addition of vegetable oil in this formula effectively lubricates the surface of cat litter, inhibits the generation of dust during the pelleting process, and improves the surface smoothness and roundness of the pellets; the optimized dosage balances dust suppression effect and pellet structural strength.

[0010] Bamboo leaf powder is rich in flavonoids and polyphenols, natural antibacterial and deodorizing ingredients. Working synergistically with SAP (Sterilized Alcohol), it effectively inhibits odor production while efficiently absorbing liquid. Furthermore, the SAP particles are evenly embedded in the granular matrix, preventing the generation of additional dust. Bamboo leaf powder effectively absorbs and decomposes odor-causing substances such as ammonia and thiols in cat urine, enhancing the deodorizing performance of the cat litter. Simultaneously, bamboo leaf powder has a certain degree of water absorption, further increasing the liquid absorption rate in synergy with SAP. After SAP is added, it quickly absorbs liquid and forms a gel, significantly increasing the water absorption rate and absorption capacity of the cat litter. Its strong water-locking ability also helps the cat litter clump quickly and prevents the clumps from breaking apart.

[0011] Cassava flour, as the main binder and molding matrix, gelatinizes upon contact with water to form a viscous gel that binds the raw material particles together. Adding an appropriate amount can effectively improve the particle agglomeration strength and molding rate. At the same time, cassava flour is completely biodegradable and does not affect the overall environmental friendliness of the product.

[0012] Guar gum is a natural plant gum with good thickening and binding properties. When used in conjunction with tapioca flour as an auxiliary binder, it improves the formability and surface density of particles, while also enhancing the drop resistance of clumps after agglomeration.

[0013] The entire formula is made from biodegradable plant materials. The product can be flushed down the toilet and quickly disintegrates, putting no burden on the water treatment system and exhibiting excellent environmental friendliness.

[0014] A method for preparing plant-based cat litter, specifically including the following steps: (1) Preparation of modified corn cob powder; (2) Place the modified corn cob powder, cassava powder, SAP, bamboo leaf powder, and guar gum in a mixer and mix thoroughly; add vegetable oil and continue mixing; add water to adjust the total moisture content of the materials to 20-30%; (3) Add the mixture to a ring die pellet mill and form cylindrical pellets with a diameter of 2-3 mm and a length of 5-10 mm under appropriate pressure; (4) Place the granules in an oven and dry them at 50-65°C until the moisture content is 5-8%; (5) Remove unqualified particles and powder by vibrating screen to obtain finished plant cat litter, which is then vacuum packaged and stored.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention is the first to combine sodium bicarbonate solution pre-soaking with steam explosion in the modification of corn cob particles, and the two-step process has a clear synergistic effect mechanism. The weakly alkaline sodium bicarbonate (NaHCO3) solution (pH approximately 8.3) plays a triple role in the pre-soaking stage: ① Saponifying long-chain fatty acids in the waxy layer on the surface of the corn cob, converting them into water-soluble soap salts and removing them, thus eliminating the hydrophobic barrier to steam permeation; ② Promoting the hydrolysis of acetyl groups in hemicellulose to generate acetic acid, forming an acidic microenvironment in the subsequent explosion cavity, and autocatalytically accelerating the breakage of hemicellulose glycosidic bonds; ③ Na... + Competition with inter-chain hydrogen bonds in cellulose causes slight swelling of the cellulose crystalline regions, reducing crystallinity and pre-opening molecular-level channels for vapor permeation. The steam explosion at 1.4 MPa / 190 s further amplifies the structural weakening effect accumulated during pre-impregnation into a macroscopic porous morphology: the cell walls burst from the inside upon instantaneous depressurization, forming numerous open cracks and channels, significantly increasing the specific surface area, fully exposing the hydroxyl groups in the amorphous regions of cellulose, and greatly increasing the number of hydrophilic adsorption sites.

[0016] This unique microstructural reconstruction and the opening of multi-level pores provide an excellent topological space and physicochemical anchoring point for capturing and locking the core odor source in cat urine—3-methyl-3-mercapto-1-butanol (MMB). Specifically: on the one hand, the significantly broadened mesoporous system (7.0116 nm) after modification (MCC) and the layered multi-scale structure form a highly efficient physical capillary network, which can rapidly adsorb and lock free MMB molecules and water into the deep layers of the framework in a very short time, thereby physically blocking their diffusion and volatilization into the air; on the other hand, the large number of hydrophilic hydroxyl groups fully exposed after the explosion can form strong hydrogen bond crosslinks and intermolecular anchoring with the sensitive groups in the MMB structure. In addition, the weakly alkaline environment of NaHCO3 remaining on the inner wall of the pores during the pre-impregnation stage can also effectively regulate the charge state of the thiol molecules and inhibit their volatility. This synergistic effect of "spatial capillary odor locking" and "surface chemical anchoring" endows the modified corn cob particles with extremely excellent MMB odor control capabilities, possessing significant industrial application value in the fields of high-end pet bedding and environmentally friendly absorbent materials. The resulting plant-based cat litter exhibits significant advantages in terms of water absorption rate (up to 826%), clumping strength (up to 93.47%), dust rate (0.28%), deodorization rate (up to 99.98%), and flushing performance. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 Different modification processes significantly regulate and influence the microscopic surface morphology of corn cobs. Detailed Implementation

[0018] The preferred embodiments of the present invention are described below. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0019] Example All raw materials used in the examples are commercially available products, with the following specific specifications: corn cob granules were purchased from an agricultural processing by-product market, with a particle size of 4-6 mm; baking soda was food grade; cassava flour was edible grade cassava flour that passed through 80 mesh; superabsorbent polymer (SAP) was sodium polyacrylate series; bamboo leaf powder was bamboo leaf powder that passed through 80 mesh; vegetable oil was edible soybean oil; and guar gum was food grade.

[0020] Preparation of corn cob powder Corn cob particles with a diameter of approximately 5 mm were placed in a container, and a 1.6% sodium bicarbonate solution was prepared. This solution was sprayed evenly onto the surface of the particles using a spray bottle, with the solution volume being 50% of the dry weight of the particles (i.e., 50 g of sodium bicarbonate solution per 100 g of corn cob particles). After mixing, the solution was allowed to stand for 1 hour to allow the sodium bicarbonate solution to fully penetrate the particles. The pretreated particles were then loaded into the explosion chamber of a steam explosion machine. After sealing, saturated steam was introduced, and the pressure was increased to 1.4 MPa. Timing was then maintained for 190 seconds, after which the pressure relief valve was opened instantaneously to complete the explosion. The exploded corn cobs were rinsed twice with 50°C warm water, filtered, and then dried in a 105°C oven until the moisture content was ≤10%. After pulverizing, the corn cobs were passed through a 60-mesh sieve to obtain modified corn cob powder (MCC), which was then set aside. Simultaneously, unmodified corn cobs with a diameter of approximately 5 mm were directly pulverized and passed through a 60-mesh sieve to obtain natural corn cob powder (CC).

[0021] To verify the synergistic modification effect of sodium bicarbonate pre-impregnation and steam explosion, the following six groups of corn cob raw materials were set up for comparison: the alkali-explosion combined modified corn cob powder (MCC-AB) prepared by sodium bicarbonate solution pre-impregnation combined with steam explosion treatment was used as the raw material of the example; steam-exploded corn cob powder (MCC-B) prepared by steam explosion treatment only (without sodium bicarbonate pre-impregnation), alkali-treated corn cob powder (MCC-A) prepared by sodium bicarbonate solution pre-impregnation only (without steam explosion) and unmodified corn cob powder without any modification treatment (MCC-0) were used as control raw materials, and the rest of the formulation composition and preparation steps were exactly the same. In addition, based on MCC-AB modified corn cob powder, two additional sets of optimized auxiliary material ratio examples were set up: MCC-AB-2 (33g corn cob powder, 12g cassava powder, 4g bamboo leaf powder, 0.3g vegetable oil, 3g guar gum) and MCC-AB-3 (27g corn cob powder, 18g cassava powder, 6g bamboo leaf powder, 0.9g vegetable oil, 4g guar gum) to investigate the influence of the dosage of each auxiliary material on the overall performance of cat litter.

[0022] Table 1. Comparison of specific surface area and pore structure of corn cobs before and after modification.

[0023] Example 1 (MCC-AB-1) Weigh 30g of modified corn cob powder, 15g of cassava powder, 0.5g of SAP, 2g of bamboo leaf powder, and 4g of guar gum. Place them in a mixer and stir evenly. Add 0.6g of vegetable oil and continue stirring for 2 minutes. Add water to adjust the total moisture content to about 25%. Add the mixture to a granulator to form cylindrical granules (about 2mm in diameter and about 8mm in length). Dry in a 55℃ oven until the moisture content is 5-6%. Screen with a vibrating screen to obtain MCC-AB-1 cat litter.

[0024] Example 2 (MCC-B) Weigh out 30g of corn cob powder, 15g of cassava powder, 0.5g of SAP, 2g of bamboo leaf powder, and 4g of guar gum obtained by steam explosion treatment only (without pre-impregnation with baking soda). Place them in a mixer and stir evenly. Then add 0.6g of vegetable oil and continue stirring for 2 minutes. Add water to adjust the total moisture content to about 25%. The granulation, drying, and sieving steps are the same as in Example 1 to obtain MCC-B cat litter.

[0025] Example 3 (MCC-A) Weigh out 30g of corn cob powder, 15g of cassava powder, 0.5g of SAP, 2g of bamboo leaf powder, and 4g of guar gum that have only been pre-treated with baking soda solution (without steam explosion), place them in a mixer and stir evenly, then add 0.6g of vegetable oil and continue stirring for 2 minutes; add water to adjust the total moisture content to about 25%; the granulation, drying, and sieving steps are the same as in Example 1, and the MCC-A cat litter is obtained.

[0026] Implementation 4 (MCC-0) Weigh out 30g of unmodified corn cob powder, 15g of cassava powder, 0.5g of SAP, 2g of bamboo leaf powder, and 4g of guar gum without any modification treatment. Place them in a mixer and stir evenly. Then add 0.6g of vegetable oil and continue stirring for 2 minutes. Add water to adjust the total moisture content to about 25%. The granulation, drying, and sieving steps are the same as in Example 1 to obtain MCC-0 cat litter.

[0027] Example 5 (MCC-AB-2) Weigh 33g of MCC-AB modified corn cob powder, 12g of cassava powder, 0.5g of SAP, 4g of bamboo leaf powder, and 3g of guar gum. Place them in a mixer and stir evenly. Add 0.3g of vegetable oil and continue stirring for 2 minutes. Add water to adjust the total moisture content to about 25%. The granulation, drying, and sieving steps are the same as in Example 1 to obtain MCC-AB-2 cat litter.

[0028] Example 6 (MCC-AB-3) Weigh 27g of MCC-AB modified corn cob powder, 18g of cassava powder, 0.4g of SAP, 6g of bamboo leaf powder, and 4g of guar gum. Place them in a mixer and stir evenly. Add 0.9g of vegetable oil and continue stirring for 2 minutes. Add water to adjust the total moisture content to about 25%. The granulation, drying, and sieving steps are the same as in Example 1 to obtain MCC-AB-3 cat litter.

[0029] Table 1. Raw material composition (parts by weight) for each formula

[0030] Performance tests of each formulation in the examples The cat litter prepared in Examples 1 to 6 was subjected to the following five performance tests, and the results are shown in Table 2.

[0031] Water absorption rate determination: Weigh equal mass of cat litter samples, place them in a container and spread them evenly, then add excess physiological saline to soak them for 2 minutes, remove the samples, let them stand on a filter screen for 5 minutes, weigh them, record the mass change before and after water absorption, and evaluate the water absorption performance of the cat litter by calculating the water absorption rate. Repeat 3 times and take the average value.

[0032] Clump strength test: Spread 1 kg of cat litter evenly in the litter box, add 10 mL of physiological saline in the center of the litter box using a graduated cylinder, let it stand for 5 min to allow it to clump together fully, then carefully remove the clumps and place them on a sieve or plate, and drop them freely from a specified height of 60 cm. Repeat five times and observe the integrity and breakage of the clumps. The degree of damage or residual mass is used to characterize the clump strength. Repeat 3 times and take the average value.

[0033] Dust rate determination: The dust rate was determined using a manual sieving method with a 100-mesh standard sieve. 100.00g of cat litter sample was weighed, gently mixed, and placed in a 100-mesh standard test sieve, with the sieve cover closed to reduce dust escape. Sieving was performed manually in a horizontal reciprocating motion at a frequency of 2 times / s for 1 minute, maintaining consistent operation throughout the process. After sieving, the dust passing through the 100-mesh sieve was collected and weighed. Each test was performed in triplicate. The dust rate (%) was calculated as the ratio of the mass of the dust passing through the sieve to the initial sample mass, used to characterize the dust generation level of the cat litter product.

[0034] Deodorization performance test: 2 g of cat litter sample was weighed and added to a 20 ml round-bottom transparent screw-top bottle. Then, 0.4 mL of 0.1 mg / mL 3-mercapto-3-methyl-1-butanol (MMB) solution was added. After shaking thoroughly for 1 h, the sample was allowed to stand at room temperature for 24 h to reach adsorption equilibrium. Subsequently, gas chromatography-ion mobility spectrometry (GC-IMS) was used for detection, with three parallel measurements and the average value taken. The deodorization rate (%) was calculated based on the change in the initial and residual concentration of MMB, which was used to characterize the adsorption performance of cat litter for odor substances.

[0035] Flushing performance test: The cat litter sample was evenly spread in a container with a height of 5 cm. 10 mL of physiological saline was added to the surface of the litter using a pipette, and allowed to stand for 5 minutes to fully absorb water and form clumps. The clumps were then carefully removed and weighed. The clumps were transferred to a beaker containing 500 mL of deionized water and stirred at 300 rpm on a magnetic stirrer to simulate the flushing process until the system was basically stable. After stirring, the mixture was filtered through a 2 mm sieve, and the undispersed residue was collected and weighed directly. The percentage of residue to the total mass of the clumps was calculated to evaluate the flushing performance of the cat litter. The experiment was performed in triplicate, and the average value was taken.

[0036] Table 2 Performance test results of various cat litter formulations

[0037] Note: The data in Table 2 are experimental test results.

[0038] As shown in Table 2, the MCC-AB modified corn cob plant-based cat litter prepared in Examples 1-6 of this invention exhibits significant advantages over MCC-B, MCC-A, and MCC-0 in terms of water absorption, clumping strength, dust content, deodorization performance, and flushing ability, fully verifying the effectiveness of the sodium bicarbonate-assisted steam explosion combined modification process. Both MCC-AB-2 and MCC-AB-3 utilize MCC-AB modified corn cob powder, and their product performance is further optimized by adjusting the auxiliary material ratio: MCC-AB-2 (water absorption 786%, deodorization 9...) The MCC-AB series (9.00%, dust rate 0.40%) showed outstanding performance in dust suppression and flushing properties; the MCC-AB-3 (733% water absorption, 93.09% clumping strength, 99.41% deodorization rate) had a greater advantage in clumping strength and deodorization. The overall performance of the three MCC-AB series formulations was significantly better than that of MCC-B, MCC-A and MCC-0, indicating that the amount of corn cob powder, cassava powder, bamboo leaf powder and vegetable oil added are all important factors affecting the overall performance of cat litter, and can be optimized and selected within the scope of the claims of this invention according to the product positioning.

[0039] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. Baking soda-assisted steam explosion modified corncob plant-based cat litter, characterized in that, The raw materials include the following parts by weight: 27-33 parts modified corn cob powder, 12-18 parts cassava powder, 0.4-0.6 parts superabsorbent resin, 2-6 parts bamboo leaf powder, 0.3-0.9 parts vegetable oil, and 3-4 parts guar gum.

2. The baking soda-assisted steam explosion modified corncob plant-based cat litter as described in claim 1, characterized in that, The modified corn cob powder was prepared by a combination of pre-impregnation with baking soda solution and steam explosion. The specific preparation method is as follows: Place the corn cob kernels in a container, prepare a baking soda solution, and spray it evenly on the surface of the corn cob kernels to allow the solution to fully penetrate into the kernels. Let it stand to complete the pre-soaking. The pre-soaked corn cob particles are loaded into the blasting chamber of a steam blasting machine, sealed, and saturated steam is introduced to stabilize the pressure. After the pressure stabilization is completed, the pressure relief valve is opened instantly to complete the blasting. The blasted corn cob particles are rinsed with warm water 2-3 times to remove free alkali and water-soluble degradation products. They are then dried in an oven, pulverized by a pulverizer, and sieved to obtain modified corn cob powder.

3. The baking soda-assisted steam explosion modified corncob plant-based cat litter as described in claim 2, characterized in that, The corn cob particles have a diameter of 4–6 mm.

4. The baking soda-assisted steam explosion modified corncob plant-based cat litter as described in claim 2, characterized in that, The baking soda solution is an aqueous solution with a mass fraction of 1.6%, and the amount of baking soda solution used is 50 wt% of the dry weight of the corn cob particles.

5. The baking soda-assisted steam explosion modified corncob plant-based cat litter as described in claim 2, characterized in that, Saturated steam was introduced to increase the pressure to 1.4 MPa, and the pressure was maintained at this level for 190 seconds.

6. The method for preparing cat litter according to claim 1, specifically comprising the following steps: (1) Preparation of modified corn cob powder; (2) Place the modified corn cob powder, cassava powder, SAP, bamboo leaf powder, and guar gum in a mixer and mix thoroughly; add vegetable oil and continue mixing; add water to adjust the total moisture content of the materials to 20-30%; (3) Add the mixture to a ring die pellet mill and form cylindrical pellets with a diameter of 2-3 mm and a length of 5-10 mm under appropriate pressure; (4) Place the granules in an oven and dry them at 50-65°C until the moisture content is 5-8%; (5) Remove unqualified particles and powder by vibrating screen to obtain finished plant cat litter, which is then vacuum packaged and stored.

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