Natural latex solidification method

Abstract

The invention discloses a natural latex solidification method, which belongs to the technical field of natural rubber production, and comprises the following steps: carrying out ammonia removal treatment on natural latex; grinding zinc oxide in a ball mill to obtain a zinc oxide dispersion; adding the zinc oxide dispersion into the ammonia-removed natural latex, and uniformly stirring; and pouring the uniformly mixed zinc oxide dispersion and natural latex into a mold, and freezing in a cold box at-10 DEG C to-80 DEG C for 4-24 hours to obtain the solidified natural rubber. According to the method, the natural latex can be directly solidified and formed at a relatively low temperature without introducing acid, so that the problems of environmental pollution, high energy consumption and the like caused by solidification methods such as acid solidification and the like are fundamentally solved, a large amount of water resources can be saved, and pollution emission is reduced; meanwhile, liquid carbon dioxide filling and secondary film pressing are not needed, the process is simpler, the condition requirement is lower, production operation is easier, and the cost is lower.

Description

Technical Field

[0001] The invention relates to the technical field of natural rubber production, in particular to a natural latex coagulation method. Background Art

[0002] Natural rubber latex usually needs to be solidified before it can enter the next step of dehydration and drying to obtain raw rubber, and the obtained raw rubber can be obtained into different rubber products after open and closed mixing. Therefore, the coagulation of natural rubber latex is an important link for natural latex to become natural rubber products.

[0003] Traditional natural rubber latex coagulation methods include chemical, biological and physical coagulation methods; chemical coagulation methods include acid coagulation and inorganic salt coagulation; biological coagulation methods include microbial coagulation and enzyme coagulation; physical coagulation methods include natural coagulation and heating coagulation. In addition, there are some new coagulation methods, such as microwave coagulation, vacuum coagulation and electrophoresis coagulation. At present, the most commonly used natural rubber latex coagulation method is acid coagulation. By adding organic acids such as formic acid and acetic acid to natural rubber latex, the pH value of fresh latex is reduced, the double electric layer is compressed, the potential is neutralized, the protective layer of natural rubber latex is destroyed, and the rubber particles continue to aggregate, thereby coagulating the latex. At present, factories generally use acid coagulation, and the raw rubber obtained is of good quality and color. However, acid coagulation has many disadvantages: (1) Acid coagulation will produce a lot of waste liquid, polluting the environment; (2) Acid coagulation will cause certain corrosion to mechanical equipment; (3) Acid coagulation is costly, and cleaning rubber will also waste a lot of water resources. Therefore, it is urgent to develop a new natural rubber latex coagulation method - low temperature freezing method.

[0004] The method of using low temperature freezing to shape materials is often used to prepare porous aerogels and hydrogels, but there are few reports on the use of low temperature freezing to solidify natural latex. After searching, the Chinese patent publication number CN109627486A discloses a pure natural latex mold cup and its preparation process, which mixes the raw latex and dispersion, foams, freezes, shapes and vulcanizes to obtain the product, wherein liquid carbon dioxide (especially -78°C) is used to combine freezing and gelling into one, and then the process of pressing and molding, but there are the following problems: First, extremely low temperature liquid carbon dioxide is required for freezing; Second, the condition for gelation is that there is ammonia in the latex. Ammonia, carbon dioxide and zinc ions react to form an ammonia-zinc complex to gel. It cannot be simply frozen to solidify. Third, carbon dioxide needs to be fully flushed in, otherwise problems such as bubbles will occur; Fourth, two times of lamination are required.

[0005] In addition, although zinc oxide is used, it is used as an activator, and the activator usually plays a role in promoting vulcanization and increasing the degree of cross-linking in latex products. Summary of the invention

[0006] In view of the above problems, the object of the present invention is to provide a method for coagulating natural rubber latex, which utilizes zinc oxide in combination with low-temperature freezing conditions to coagulate natural rubber latex.

[0007] In order to achieve these purposes and other advantages of the present invention, the present invention provides a method for coagulating natural latex, which combines zinc oxide with natural latex and utilizes low-temperature freezing at the same time, so that the natural latex can be coagulated and formed under low-temperature freezing conditions, and remain in a coagulated state after thawing, and will not melt after thawing.

[0008] In some embodiments, freezing and solidification can be achieved under low-temperature freezing conditions of -10°C, -24°C, or -80°C.

[0009] In some embodiments, the added content of zinc oxide is 1 to 10 parts, that is, 1 to 10 parts by weight of zinc oxide is added to 100 parts by weight of natural latex to achieve freezing and solidification. In the actual production process, the coagulation effect can be adjusted by adjusting the amount of zinc oxide added, preferably the above-mentioned addition ratio. If the amount added is too large, it will directly lead to flocculation of natural latex, which will easily affect the introduction of functional fillers and the strength of natural latex products.

[0010] In some embodiments, it is found that pure natural latex cannot be directly frozen and solidified in a low-temperature freezing environment; however, natural latex can be frozen and solidified after adding zinc oxide dispersion, and the addition of sulfur, accelerators, and activators has no effect on the solidification of latex. Therefore, the method of using zinc oxide combined with low-temperature freezing to solidify natural latex is simple in process, low in cost, and can save a lot of water resources.

[0011] Preferably, in the method, freezing and solidification are achieved under low-temperature freezing conditions of -10°C to 80°C; and the solid content of zinc oxide added per 100 parts of natural latex is 1 to 10 parts.

[0012] Preferably, in the method, the low-temperature freezing method is any one or more of unidirectional freezing, bidirectional freezing, homogeneous freezing, radial freezing, gradient freezing and the like.

[0013] Preferably, in the method, the solid content of the natural rubber latex is 20%-65%.

[0014] Preferably, in the method, the freezing and solidification process is not affected by other additives, and other additives include: one or more of sulfur, accelerator M, accelerator ZDC, stearic acid, diffusant NF, potassium hydroxide, casein and the like.

[0015] Preferably, in the method, when the zinc oxide dispersion is prepared, the mass ratio of zinc oxide: water: diffusing agent NF: potassium hydroxide: casein is 1~10: 1~40: 0.05~0.2: 0.05~0.2: 0.5~3.

[0016] Preferably, the method specifically comprises: Step 1, after natural rubber latex is prepared into a solution of a certain concentration, ammonia is removed from the natural rubber latex by formaldehyde method; Step 2, according to the weight parts of the components: 1-10 parts of zinc oxide, 1-40 parts of water, 0.05-1 parts of potassium hydroxide, 0.05-1 parts of diffusant, and 0.5-3 parts of casein; taking a certain amount of casein, diffusant NF, and potassium hydroxide and adding them into water to prepare a solution of a certain concentration, and then placing it in a ball mill together with a certain amount of zinc oxide for grinding, the grinding time is 2-4 hours, and the ball mill speed is 500-3000 rpm; Step 3, adding the zinc oxide dispersion obtained after grinding in step 2 to the natural rubber latex after ammonia removal treatment, and stirring evenly; Step 4: Pour the zinc oxide dispersion and natural latex mixed in step 3 into a mold, freeze them in a -10°C to -80°C freezer for 4 to 24 hours, and solidify natural latex after the freezing is completed.

[0017] Using formaldehyde to remove ammonia from natural rubber latex is a common method. The basic principle is to remove ammonia from natural rubber latex through a chemical reaction between formaldehyde and ammonia.

[0018] The present invention has at least the following beneficial effects: 1. The present invention firstly uses zinc oxide and low-temperature freezing to coagulate natural latex. Zinc oxide enables natural latex to solidify and form under low-temperature freezing conditions, and keeps the solidified state after thawing without melting, making low-temperature freezing coagulation of natural latex possible. It can replace high-cost and high-pollution coagulation methods such as acid coagulation and inorganic salt coagulation, reduce environmental pollution, and has simple process, low cost, and can save a lot of water resources.

[0019] 2. The natural latex coagulation method based on the freezing and coagulation technology of the present invention can realize direct freezing and coagulation molding at a relatively low temperature, does not require the injection of liquid carbon dioxide, does not require secondary film pressing, has a simpler process, has lower condition requirements, is easier to carry out production operations, and has lower costs. In one embodiment, direct freezing and coagulation molding can be performed using a low temperature of -10°C.

[0020] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Sample image obtained in Example 1.1; Figure 2 This is the sample image obtained in Example 1.2; Figure 3 This is the sample image obtained in Example 1.3; Figure 4 This is the sample image obtained in Example 1.4; Figure 5 This is the sample image obtained in Example 1.5; Figure 6 This is the sample image obtained in Example 1.6; Figure 7 This is the sample image obtained in Example 1.7; Figure 8 This is the sample image obtained in Example 1.8; Fig. 9 This is the sample image obtained in Example 1.9; Fig.10 This is the sample image obtained in Example 2.0; Fig.11 This is the sample picture obtained in Example 2.1. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below in conjunction with embodiments so that those skilled in the art can implement the invention with reference to the description.

[0023] Example 1.1 This embodiment provides an example that pure natural latex cannot be directly frozen and coagulated.

[0024] The main raw material of the present embodiment is 100 parts of pure natural rubber latex.

[0025] Cryo-solidification involves the following steps: Step 1, weighing a certain mass of natural rubber latex and preparing a natural rubber latex solution with a concentration of 60%; Step 2, removing ammonia from natural rubber latex using a formaldehyde method; Step 3, leaving the natural rubber latex after ammonia removal treatment to stand for 2 hours; Step 4: Pour the natural latex obtained in step 3 into a mold, freeze it evenly in a -24°C freezer for 24 h, and thaw it at room temperature after freezing.

[0026] The process results are as follows Figure 1 shown.

[0027] Example 1.2 This example provides an example of a method for coagulating natural rubber latex using zinc oxide in combination with low-temperature freezing.

[0028] The raw materials of this embodiment are: natural rubber latex: 100 parts; zinc oxide: 3 parts; potassium hydroxide: 0.1 parts; diffusing agent NF: 0.1 parts; casein: 0.8 parts; water 1-40 parts.

[0029] Cryo-solidification involves the following steps: Step 1, weighing a certain amount of natural rubber latex and additives according to weight portions for use; Step 2, after preparing the natural rubber latex into a latex solution with a concentration of 60%, removing ammonia from the natural rubber latex by formaldehyde method; Step 3, adding the auxiliary agent casein, the diffusing agent NF, and potassium hydroxide into water to prepare a solution, and then grinding the solution together with zinc oxide in a ball mill for 3 hours at a ball mill speed of 1500 rpm to obtain a zinc oxide dispersion; Step 4, adding the zinc oxide dispersion obtained in step 3 to the natural rubber latex after ammonia removal treatment, stirring evenly and setting aside; Step 5: Pour the zinc oxide dispersion and natural latex mixed in step 4 into a mold, and freeze them evenly in a -24°C freezer for 24 hours. After the freezing is completed, solidified natural latex can be obtained.

[0030] The process results are as follows Figure 2 shown.

[0031] Example 1.3 This embodiment provides an example of not using zinc oxide, resulting in the inability of natural rubber latex to be frozen and solidified.

[0032] The raw material ratio of this embodiment is as follows: natural rubber latex: 100 parts; sulfur: 2.5 parts; accelerator M: 1.5 parts; stearic acid: 3 parts; potassium hydroxide: 0.1 parts; diffusing agent NF: 0.1 parts; casein: 0.8 parts; water 1-40 parts.

[0033] The steps include: Step 1, weighing a certain amount of natural rubber latex and additives according to weight portions for use; Step 2, after preparing the natural rubber latex into a latex solution with a concentration of 60%, removing ammonia from the natural rubber latex by formaldehyde method; Step 3, adding the auxiliary agent casein, the diffusing agent NF, and potassium hydroxide into water to prepare a solution, and then grinding them with sulfur, the accelerator M, and stearic acid in a ball mill for 3 hours at a ball mill speed of 1500 rpm to obtain a dispersion; Step 4, adding the dispersion obtained in step 3 to the natural rubber latex after ammonia removal treatment, stirring evenly and setting aside; Step 5: Pour the natural latex mixed with the dispersion obtained in step 4 into a mold, and freeze it evenly in a -24°C freezer for 24 hours. After the freezing is completed, solidified natural latex can be obtained.

[0034] The process results are as follows Figure 3 shown.

[0035] Example 1.4 This example shows an example of a method for coagulating natural rubber latex using zinc oxide in combination with low temperature freezing.

[0036] The raw material ratio of this embodiment is as follows: 100 parts of natural rubber latex; 2.5 parts of sulfur; 3 parts of zinc oxide; 1.5 parts of accelerator M; 3 parts of stearic acid; 0.1 parts of potassium hydroxide; 0.1 parts of diffusing agent NF; 0.8 parts of casein; and 1-40 parts of water.

[0037] The steps include: Step 1, weighing a certain amount of natural rubber latex and additives according to weight portions for use; Step 2, preparing the natural rubber latex into a latex solution with a concentration of 60%, and removing ammonia from the natural rubber latex by formaldehyde method; Step 3, adding auxiliary agent casein, diffusing agent NF, and potassium hydroxide into water to prepare a solution, and then placing them in a ball mill together with sulfur, zinc oxide, accelerator M, and stearic acid for grinding for 3 hours at a ball mill speed of 1500 rpm to obtain a dispersion; Step 4, adding the dispersion obtained in step 3 to the natural rubber latex after ammonia removal treatment, stirring evenly and setting aside; Step 5: Pour the dispersion and natural latex mixed in step 4 into a mold, and freeze them evenly in a -24°C freezer for 24 hours. After the freezing is completed, solidified natural latex can be obtained.

[0038] The process results are as follows Figure 4 shown.

[0039] Example 1.5 This example shows an example of a method for coagulating natural rubber latex using zinc oxide in combination with low temperature freezing.

[0040] The raw material ratio of this embodiment is as follows: 100 parts of natural rubber latex; 2.5 parts of sulfur; 5 parts of zinc oxide; 1.5 parts of accelerator M; 3 parts of stearic acid; 0.1 parts of potassium hydroxide; 0.1 parts of diffusing agent NF; 0.8 parts of casein; and 1-40 parts of water.

[0041] The steps include: Step 1, weighing a certain amount of natural rubber latex and additives according to weight portions for use; Step 2, preparing the natural rubber latex into a latex solution with a concentration of 60%, and removing ammonia from the natural rubber latex by formaldehyde method; Step 3, after adding casein, diffusing agent NF and potassium hydroxide into water to prepare a solution, the solution was placed in a ball mill together with sulfur, zinc oxide, accelerator M and stearic acid, and the grinding time was 3 hours at a ball mill speed of 1500 rpm to obtain a dispersion; Step 4, adding the dispersion obtained in step 3 to the natural rubber latex after ammonia removal treatment, stirring evenly and setting aside; Step 5: Pour the dispersion and natural latex mixed in step 4 into a mold, and freeze them evenly in a -24°C freezer for 24 hours. After the freezing is completed, solidified natural latex can be obtained.

[0042] The process results are as follows Figure 5 shown.

[0043] Example 1.6 This embodiment provides an example in which pure natural latex cannot be coagulated, and no ammonia removal treatment is performed.

[0044] The main raw material of the present embodiment is 100 parts of pure natural rubber latex.

[0045] Cryo-solidification involves the following steps: Step 1, weighing a certain mass of natural rubber latex and preparing a latex solution with a concentration of 60%; Step 2: Pour the natural latex obtained in step 1 into a mold, freeze it evenly in a -24°C freezer for 24 h, and thaw it at room temperature after freezing.

[0046] The process results are as follows Figure 6 shown.

[0047] Example 1.7 This example shows an example of a method for coagulating natural rubber latex using zinc oxide in combination with low temperature freezing.

[0048] The raw materials of this embodiment are: natural rubber latex: 100 parts; zinc oxide: 3 parts; water: 1-40 parts.

[0049] The steps include: Step 1, weighing a certain amount of natural rubber latex and additives according to weight portions for use; Step 2, preparing the natural rubber latex into a latex solution with a concentration of 60%, and removing ammonia from the natural rubber latex by formaldehyde method; Step 3, grinding zinc oxide and an appropriate amount of water in a ball mill for 3 hours at a ball mill speed of 1500 rpm to obtain a zinc oxide dispersion; Step 4, adding the zinc oxide dispersion obtained in step 3 to the natural rubber latex after ammonia removal treatment, stirring evenly and setting aside; Step 5: Pour the zinc oxide dispersion and natural latex mixed in step 4 into a mold, and freeze them evenly in a -24°C freezer for 24 hours. After the freezing is completed, solidified natural latex can be obtained.

[0050] The process results are as follows Figure 7 shown.

[0051] Example 1.8 This example shows an example of a method for coagulating natural rubber latex using zinc oxide in combination with low temperature freezing.

[0052] The raw material ratio of this embodiment is as follows: 100 parts of natural rubber latex; 3 parts of zinc oxide; 0.1 parts of potassium hydroxide; 0.1 parts of diffusing agent NF; 0.8 parts of casein; and 1-40 parts of water.

[0053] The steps include: Step 1, weighing a certain amount of natural rubber latex and additives according to weight portions for use; Step 2, preparing the natural rubber latex into a latex solution with a concentration of 60%, and removing ammonia from the natural rubber latex by formaldehyde method; Step 3, adding the auxiliary agent casein, the diffusing agent NF, and potassium hydroxide into water to prepare a solution, and then grinding them together with zinc oxide in a ball mill for 3 hours at a ball mill speed of 1500 rpm to obtain a dispersion; Step 4, adding the dispersion obtained in step 3 to the natural rubber latex after ammonia removal treatment, stirring evenly and setting aside; Step 5: Pour the zinc oxide dispersion and natural latex mixed in step 4 into a mold, and freeze them evenly in a -24°C freezer for 24 hours. After the freezing is completed, solidified natural latex can be obtained.

[0054] The process results are as follows Figure 8 shown.

[0055] Example 1.9 This example shows an example of a method for coagulating natural rubber latex using zinc oxide in combination with low temperature freezing.

[0056] The raw material ratio of this embodiment is as follows: 100 parts of natural rubber latex; 2.5 parts of sulfur; 7 parts of zinc oxide; 1.5 parts of accelerator M; 3 parts of stearic acid; 0.1 parts of potassium hydroxide; 0.1 parts of diffusing agent NF; 0.8 parts of casein; and 1-40 parts of water.

[0057] The steps include: Step 1, weighing a certain amount of natural rubber latex and additives according to weight portions for use; Step 2, preparing the natural rubber latex into a latex solution with a concentration of 60%, and removing ammonia from the natural rubber latex by formaldehyde method; Step 3, after adding casein, diffusing agent NF and potassium hydroxide into water to prepare a solution, the solution was placed in a ball mill together with sulfur, zinc oxide, accelerator M and stearic acid, and the grinding time was 3 hours at a ball mill speed of 1500 rpm to obtain a dispersion; Step 4, adding the dispersion obtained in step 3 to the natural rubber latex after ammonia removal treatment, stirring evenly and setting aside; Step 5: Pour the dispersion and natural latex mixed in step 4 into a mold, and freeze them evenly in a -24°C freezer for 24 hours. After the freezing is completed, solidified natural latex can be obtained.

[0058] The results are as follows Fig. 9 As shown, if the zinc oxide addition ratio is too large, the latex will directly flocculate after being added to the latex.

[0059] Example 2.0 This example shows an example of a method for coagulating natural rubber latex using zinc oxide in combination with low temperature freezing.

[0060] The raw material ratio of the natural rubber film of this embodiment is: 100 parts of natural latex; 2.5 parts of stearic acid; 1 part of accelerator M; 2 parts of sulfur; 3 parts of zinc oxide; 0.05 parts of diffusant NF; 0.05 parts of potassium hydroxide; 0.8 parts of casein; and 1-40 parts of water.

[0061] Implementation steps: Step 1, weighing a certain amount of natural rubber latex and additives according to weight portions for use; Step 2, preparing the natural rubber latex into a latex solution with a concentration of 60%, and removing ammonia from the natural rubber latex by formaldehyde method; Step 3, after adding casein, diffusing agent NF and potassium hydroxide into water to prepare a solution, the solution was placed in a ball mill together with S, zinc oxide, accelerator M and stearic acid, and the grinding time was 3 hours at a ball mill speed of 1500 rpm to obtain a dispersion; Step 4, adding the dispersion obtained in step 3 to the natural rubber latex after ammonia removal treatment, stirring evenly and setting aside; Step 5: Pour the dispersion and natural latex mixed in step 4 into a mold, and freeze them evenly in a -10°C freezer for 24 hours. After the freezing is completed, solidified natural latex can be obtained.

[0062] The results are as follows Fig.10 As shown, it can still solidify even at a freezing temperature of -10°C.

[0063] Example 2.1 This example shows an example of a method for coagulating natural rubber latex using zinc oxide in combination with low temperature freezing.

[0064] The raw material ratio of the natural rubber film of this embodiment is: 100 parts of natural latex; 2.5 parts of stearic acid; 1 part of accelerator M; 2 parts of sulfur; 3 parts of zinc oxide; 0.05 parts of diffusant NF; 0.05 parts of potassium hydroxide; 0.8 parts of casein; and 1-40 parts of water.

[0065] Implementation steps: Step 1, weighing a certain amount of natural rubber latex and additives according to weight portions for use; Step 2, preparing the natural rubber latex into a latex solution with a concentration of 60%, and removing ammonia from the natural rubber latex by formaldehyde method; Step 3, after casein, diffusing agent NF and potassium hydroxide are added into water to prepare a solution, they are respectively put together with sulfur, zinc oxide, accelerator M and stearic acid and placed in a ball mill for grinding, the grinding time is 3 hours, the ball mill speed is 1500rpm, and a dispersion is obtained; Step 4, adding the dispersion obtained in step 3 to the natural rubber latex after ammonia removal treatment, stirring evenly and setting aside; Step 5: pour the dispersion and natural latex mixed in step 4 into a mold, and freeze them at -80°C for 24 hours. After the freezing is completed, solidified natural latex can be obtained.

[0066] The results are as follows Fig.11 As shown, the product surface has obvious oriented lines after directional freezing at -80℃.

[0067] Effect comparison Figure 1 Sample image obtained in Example 1.1; Figure 2 This is the sample image obtained in Example 1.2; Figure 3 This is a sample diagram of Example 1.3; Figure 4 This is the sample image obtained in Example 1.4; Figure 5 This is the sample image obtained in Example 1.5; Figure 6 This is the sample image obtained in Example 1.6; Figure 7 This is the sample image obtained in Example 1.7; Figure 8 This is the sample image obtained in Example 1.8; Fig. 9 This is the sample image obtained in Example 1.9; Fig.10 This is the sample image obtained in Example 2.0; Fig.11 This is the sample picture obtained in Example 2.1.

[0068] It can be seen that pure natural latex cannot be frozen and solidified in a frozen environment. After adding zinc oxide to natural latex, it can be frozen and formed at -10°C, and remains solidified without melting after thawing. Adding additives such as sulfur, accelerators, and activators has no effect on the coagulation and molding of latex, which shows that only zinc oxide can be used as a freezing and solidification molding agent; it also means that the method of the present invention using zinc oxide combined with low-temperature freezing to coagulate natural latex is simple and feasible, low in cost, and can save a lot of water resources. However, the addition of zinc oxide needs to be appropriate, otherwise it is easy to cause direct flocculation of natural latex, which in turn easily affects the introduction of functional fillers and the strength of natural latex products.

[0069] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and the embodiments. They can be applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily realized.

Claims

1. A method for coagulating natural rubber latex, characterized in that: The method includes ammonia removal treatment of natural rubber latex, preparation of zinc oxide dispersion, mixing of natural rubber latex and zinc oxide dispersion, and freezing and solidification, as follows: Step 1, after natural rubber latex is prepared into a solution of a certain concentration, ammonia is removed from the natural rubber latex by formaldehyde method; Step 2, according to the weight parts of the components, at least including: 1-10 parts of zinc oxide, 1-40 parts of water, mixing and grinding in a ball mill, the grinding time is 2-4 hours, the ball mill speed is 500-3000 rpm, to obtain a zinc oxide dispersion; Step 3, adding the zinc oxide dispersion obtained after grinding in step 2 to the natural rubber latex after ammonia removal treatment, and stirring evenly; Step 4: Pour the zinc oxide dispersion and natural latex mixed in step 3 into a mold, freeze them in a -10°C to -80°C freezer for 4 to 24 hours, and solidify natural latex after the freezing is completed.

2. The solidification method according to claim 1, characterized in that The zinc oxide is used as a natural latex freezing and coagulation aid, and the freezing and coagulation treatment of the natural latex is achieved through low-temperature freezing technology.

3. The solidification method according to claim 2, characterized in that The natural rubber latex is frozen and solidified under low temperature conditions of -10°C to 80°C, and the freezing method is any one or more of unidirectional freezing, bidirectional freezing, homogeneous freezing, radial freezing, and gradient freezing.

4. The solidification method according to claim 2, characterized in that: The solid content of the natural rubber latex is 20%-65%.

5. The solidification method according to claim 2, characterized in that: The solid content of zinc oxide added to every 100 parts of natural rubber latex is 1 to 10 parts.

6. The solidification method according to claim 2, characterized in that: Step 2 also includes: according to the weight parts of the components: 1-10 parts of zinc oxide, 1-40 parts of water, 0.05-1 parts of potassium hydroxide, 0.05-1 parts of diffusant NF, and 0.5-3 parts of casein; taking a certain amount of casein, diffusant NF, and potassium hydroxide and adding them into water to prepare a solution of a certain concentration, placing it in a ball mill together with a certain amount of zinc oxide and grinding it, the grinding time is 2-4 hours, and the ball mill speed is 500-3000 rpm, to obtain a zinc oxide dispersion.

7. The solidification method according to claim 6, characterized in that: When preparing the zinc oxide dispersion, the mass ratio of zinc oxide: water: diffusion agent NF: potassium hydroxide: casein is 1-10: 1-40: 0.05-0.2: 0.05-0.2: 0.5-3.

8. The solidification method according to claim 2, characterized in that: The freezing and solidification process is not affected by the presence of other additives, which include one or more of sulfur, accelerator M, accelerator ZDC, stearic acid, diffuser NF, and casein.

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