A method for preventing mildew of natural rubber

Abstract

The present invention provides a method for preventing mildew of natural rubber, belonging to the field of natural rubber processing. The present invention provides a method for preventing mildew of natural rubber, and the mildew-proof agent used includes one or more of isothiazolinone, 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2(1H)-pyridinone ethanolamine salt, and dodecyl dimethyl benzyl ammonium chloride. The mildew-proof agent adopted in the present invention can kill and inhibit various fungi and molds very efficiently, effectively delay or prevent the mildew phenomenon of natural rubber during long-term storage, extend the shelf life of the product, and 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2(1H)-pyridinone ethanolamine salt and dodecyl dimethyl benzyl ammonium chloride are suitable for various natural surface environments for a long time, have good weather resistance, and are suitable for a wide pH value range and extremely high temperature environments.

Description

Technical Field

[0001] The present invention relates to the technical field of natural rubber processing, and particularly to a method for preventing mildew of natural rubber. Background Art

[0002] Natural rubber has excellent comprehensive properties and is an indispensable material for national security and economic construction. At present, natural rubber is increasingly widely used in people's lives, but the excellent properties of natural rubber are related to the biological proteins it contains. Natural rubber contains a certain amount of protein, which plays an important role in the high elasticity and tensile crystallinity of rubber. The tensile crystallinity of rubber cannot be replaced by any currently available synthetic rubber. Due to the influence of environmental and self factors, raw rubber is prone to grow various molds under humid and hot conditions. Protein has strong water absorption, which can cause the raw rubber to absorb moisture and mildew, resulting in a decrease in insulation performance. At the same time, protein is a nutrient for molds, which is more conducive to the reproduction of bacterial strains. The growth and spread of molds will damage the internal molecular structure of the raw rubber, causing irreversible changes in the apparent use performance and molecular structure of the raw rubber, resulting in poor mechanical properties, darker appearance color of the raw rubber, and even loss of use function. On the other hand, rubber products made from mildewed raw rubber pose quality and safety hazards during storage and application.

[0003] There is no relevant report on the prevention of mildew of natural rubber in the prior art. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a method for preventing mildew of natural rubber. The method provided by the present invention can be used to delay or prevent mildew during the storage of natural rubber.

[0005] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0006] The present invention provides a method for preventing mildew of natural rubber, and the mildew preventive used includes one or more of isothiazolinone, 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2(1H)-pyridone ethanolamine salt, and dodecyl dimethyl benzyl ammonium chloride.

[0007] Preferably, the mildew preventive includes 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2(1H)-pyridone ethanolamine salt and dodecyl dimethyl benzyl ammonium chloride.

[0008] Preferably, the mass ratio of 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2(1H)-pyridone ethanolamine salt to dodecyl dimethyl benzyl ammonium chloride is 1:4.

[0009] Preferably, the mildew preventive includes isothiazolinone and dodecyl dimethyl benzyl ammonium chloride.

[0010] Preferably, the mass ratio of the isothiazolinone to the dodecyldimethylbenzylammonium chloride is 1:4.

[0011] Preferably, the isothiazolinone includes 2-octyl-4-isothiazolin-3-one.

[0012] Preferably, the mildew-proof agent is used in the form of a mildew-proof agent spray, and the mildew-proof agent spray contains an organic solvent.

[0013] Preferably, the organic solvent includes propylene glycol.

[0014] Preferably, the mass content of the organic solvent in the mildew-proof agent spray is 25-90%.

[0015] Preferably, based on the size of the natural rubber being 670 mm in length, 330 mm in width, and 250 mm in height, the dosage of the mildew-proof agent spray is 10-20 mL.

[0016] The present invention provides a method for preventing mildew of natural rubber. The mildew-proof agent used includes one or more of isothiazolinone, 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2(1H)-pyridinone ethanolamine salt, and dodecyldimethylbenzylammonium chloride.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] Natural rubber is made from latex. The chemical components in latex are very complex. In addition to rubber hydrocarbons and water, there are also about 5 wt% of non-rubber substances, among which the most abundant is protein, accounting for 2 wt%-3 wt%. During the rubber-making process, a part of the latex protein flows away with the whey, and the remaining part still remains in the product. Protein has a great influence on the stability of latex and also on the performance of rubber. Its decomposition products can promote the vulcanization of rubber, improve the modulus at a specified elongation and tensile strength of rubber, delay the aging of rubber, and improve the durability of rubber products. Therefore, protein is essential and cannot be removed. On the other hand, protein has strong water absorption, can increase the water absorption and conductivity of raw rubber and rubber products, and easily causes raw rubber and rubber products to mildew. Protein also becomes a nutrient for the reproduction of molds. The mildew-proof agent adopted by the present invention can very efficiently kill and inhibit various fungi and molds, effectively delay or prevent the mildew phenomenon of natural rubber during long-term storage, extend the shelf life of the product. 1-Hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2(1H)-pyridinone ethanolamine salt and dodecyldimethylbenzylammonium chloride are suitable for various natural surface environments for a long time, have good weather resistance, and are suitable for a wide pH value range and extremely high temperature environments.

[0019] Moreover, the mildew-proof agent used in the present invention is green, environmentally friendly, safe and reliable, free of harmful substances such as formaldehyde, VOC, phenolic aldehyde, and heavy metals, colorless, odorless, non-irritating, and convenient to use. It can be applied by direct spraying, roller coating, or immersion. The mildew-proof agent used in the present invention has little impact on the various properties of raw rubber and does not damage the molecular structure and appearance of rubber. After the natural rubber is treated with mildew prevention or stored for a long time, the performance degradation rate does not exceed 10%. Specific Embodiments

[0020] The present invention provides a method for preventing mildew of natural rubber. The mildew-proof agent used includes one or more of isothiazolinone, 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2(1H)-pyridinone ethanolamine salt (hydroxypyridone, CAS No. 68890-66-4), and dodecyl dimethyl benzyl ammonium chloride (CAS No. 139-07-1).

[0021] In the present invention, unless otherwise specified, the raw materials used are commercially available products in the art.

[0022] In the present invention, the mildew-proof agent preferably includes 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2(1H)-pyridinone ethanolamine salt and dodecyl dimethyl benzyl ammonium chloride, and the mass ratio of 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2(1H)-pyridinone ethanolamine salt to dodecyl dimethyl benzyl ammonium chloride is 1:4.

[0023] In the present invention, the mildew-proof agent preferably includes isothiazolinone and dodecyl dimethyl benzyl ammonium chloride, and the mass ratio of isothiazolinone to dodecyl dimethyl benzyl ammonium chloride is preferably 1:4.

[0024] In the present invention, the isothiazolinone preferably includes 2-octyl-4-isothiazolin-3-one (CAS No. 26530-20-1).

[0025] In the present invention, the mildew-proof agent preferably includes 2-octyl-4-isothiazolin-3-one (CAS No. 26530-20-1).

[0026] In the present invention, the mildew-proof agent is preferably used in the form of a mildew-proof agent spray, and the mildew-proof agent spray preferably contains an organic solvent.

[0027] In the present invention, the organic solvent preferably includes propylene glycol, and the propylene glycol is safe and non-toxic.

[0028] In the present invention, the mass purity of the organic solvent is preferably ≥99.0%.

[0029] In the present invention, the mass content of the organic solvent in the mildew-proof agent spray is preferably 25-90%.

[0030] When the mildew-proof agent is preferably 2-octyl-4-isothiazolin-3-one, the mass content of 2-octyl-4-isothiazolin-3-one in the mildew-proof agent spray is preferably 10-15%, and the mass content of the organic solvent is preferably 85-90%. The mildew-proof agent spray can play a good mildew-proof role under high-temperature and acid-base conditions.

[0031] When the mildew-proof agent preferably includes 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2(1H)-pyridinone ethanolamine salt and dodecyl dimethyl benzyl ammonium chloride, the mass content of 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2(1H)-pyridinone ethanolamine salt in the mildew-proof agent spray is preferably 10-15%, the mass content of dodecyl dimethyl benzyl ammonium chloride is preferably 40-60%, and the mass content of the organic solvent is preferably 25-50%. The mildew-proof agent spray is suitable for various surface environments for a long time, has good weather resistance, and has obvious killing and inhibitory effects on various bacteria and molds.

[0032] When the mildew-proof agent preferably includes 2-octyl-4-isothiazolin-3-one and dodecyl dimethyl benzyl ammonium chloride, the mass content of 2-octyl-4-isothiazolin-3-one in the mildew-proof agent spray is preferably 10-15%, the mass content of dodecyl dimethyl benzyl ammonium chloride is preferably 40-60%, and the mass content of the organic solvent is preferably 25-50%. The mildew-proof agent spray has broad biological activity and good chemical stability and can effectively resist fungi.

[0033] The present invention preferably sprays the mildew-proof agent spray on the surface of natural rubber to cover the natural rubber.

[0034] In the present invention, taking the size of natural rubber as 670 mm in length, 330 mm in width, and 250 mm in height, the dosage of the mildew-proof agent spray is preferably 10-20 mL.

[0035] The present invention preferably adds the mildew-proof agent to latex to prepare a rubber product, and the latex contains natural rubber.

[0036] In the present invention, the dosage of the mildew-proof agent is preferably 0.01% of the mass of the dry rubber of the latex.

[0037] In order to further illustrate the present invention, the following describes in detail the natural rubber mildew-proof method provided by the present invention with reference to examples, but they should not be construed as limiting the protection scope of the present invention.

[0038] The anti - mildew test of natural rubber is carried out according to the methods described in GJB150.10A - 2009 Test Methods for Environmental Tests of Military Equipment Laboratories - Part 10: Mildew Test and HG / T4301 - 2012 Test Method for Anti - mildew Performance of Rubber.

[0039] The anti - mildew agents and anti - mildew sprays used in the examples

[0040] The anti - mildew agent 210 consists of 2 - octyl - 4 - isothiazolin - 3 - one;

[0041] The anti - mildew agent 753 consists of 1 - hydroxy - 4 - methyl - 6 - (2,4,4 - trimethylpentyl) - 2(1H) - pyridinone ethanolamine salt and dodecyl dimethyl benzyl ammonium chloride, and the mass ratio of 1 - hydroxy - 4 - methyl - 6 - (2,4,4 - trimethylpentyl) - 2(1H) - pyridinone ethanolamine salt to dodecyl dimethyl benzyl ammonium chloride is 1:4;

[0042] The anti - mildew agent 245 consists of 2 - octyl - 4 - isothiazolin - 3 - one and dodecyl dimethyl benzyl ammonium chloride, and the mass ratio of 2 - octyl - 4 - isothiazolin - 3 - one to dodecyl dimethyl benzyl ammonium chloride is 1:4;

[0043] The M210 anti - mildew spray includes 2 - octyl - 4 - isothiazolin - 3 - one and propylene glycol;

[0044] The M753 anti - mildew spray includes 1 - hydroxy - 4 - methyl - 6 - (2,4,4 - trimethylpentyl) - 2(1H) - pyridinone ethanolamine salt, dodecyl dimethyl benzyl ammonium chloride and propylene glycol;

[0045] The M245 anti - mildew spray includes 2 - octyl - 4 - isothiazolin - 3 - one, dodecyl dimethyl benzyl ammonium chloride and propylene glycol;

[0046] The size of the test sample is 670 mm in length, 330 mm in width and 250 mm in height.

[0047] The formula for raw rubber detection is shown in Table 1, and the evaluation of mildew grade is shown in Table 2.

[0048] Table 1 Formulation components for raw rubber performance detection

[0049] Raw material name Ratio (parts by weight) Raw rubber 100.00 Stearic acid 0.50 Zinc oxide 6.00 Accelerator M 0.50 Sulfur 3.50 Total 110.50

[0050] Table 2 Evaluation table for mildew grade of samples

[0051]

[0052]

[0053] Example 1 M210 anti - mildew spray

[0054] 1) Conduct a mold-proof test on production samples in the laboratory. Take two rubber blocks weighing 33.3 kg after production pressing, namely the blank sample and the test sample. Spray the mold-proof spray M210 (20 mL) with different mass percentages of 2-octyl-4-isothiazolin-3-one on the surface of the test sample. According to the test conditions described in HG / T 4301-2012 Rubber Mold-Proof Performance Test Method, place the blank sample and the test sample in an incubator. The results are shown in Table 3. Considering the cost comprehensively, it is preferred that the mass percentage of 2-octyl-4-isothiazolin-3-one in the mold-proof spray M210 is 10-15%.

[0055] Table 3 Optimization Results of M210 (2-octyl-4-isothiazolin-3-one)

[0056]

[0057] 2) According to the above method, spray different amounts (volumes) of the mold-proof spray M210 (with a mass percentage of 2-octyl-4-isothiazolin-3-one of 10%) on the surface of the test sample. According to the test conditions described in HG / T 4301-2012 Rubber Mold-Proof Performance Test Method, place the blank sample and the test sample in an incubator. The results are shown in Table 4. Considering the cost comprehensively, it is preferred that the dosage of the mold-proof agent spray is 10-20 mL.

[0058] Table 4 Test Results of Different Dosages of M210

[0059]

[0060] 3) Conduct a mold-proof test on raw rubber products at the natural rubber production site. Add different amounts (mass percentages) of the mold-proof spray M210 (with a mass percentage of 2-octyl-4-isothiazolin-3-one of 10%) according to the actual dry rubber amount. At the same time, produce production samples without mold-proof agent, namely the blank sample and the test sample. Conduct a mold-proof test by placing them in the warehouse for one month. Temperature: 25-31 °C, Humidity: 50-70%. The results are shown in Table 5. It can be seen that considering comprehensively, it is preferred that the dosage of the mold-proof agent spray is 0.01 wt%.

[0061] Table 5 Mold-Proof Test Results of Raw Rubber Products

[0062]

[0063] Example 2 M753 Mold-Proof Spray

[0064] 1) Conduct the mildew-proof test on production samples in the laboratory. Take two 33.3 kg rubber blocks after production pressing, namely the blank sample and the test sample. Spray different mildew-proof sprays M753 (20 mL) on the surface of the test sample. In the mildew-proof spray M753, the mass percentage of propylene glycol is 20%, and the sum of the mass percentages of 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2(1H)-pyridinone ethanolamine salt and dodecyl dimethyl benzyl ammonium chloride is 80%. According to the test conditions described in HG / T 4301-2012 Rubber Mildew-Proof Performance Test Method, place the blank sample and the test sample in an incubator. The results are shown in Table 6. It can be seen that the preferred mass ratio of 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2(1H)-pyridinone ethanolamine salt to dodecyl dimethyl benzyl ammonium chloride is 1:4.

[0065] Table 6 Optimization Results of M753

[0066]

[0067] Note: The ratio in Table 6 refers to the mass ratio of 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2(1H)-pyridinone ethanolamine salt to dodecyl dimethyl benzyl ammonium chloride.

[0068] 2) Conduct the mildew-proof test on production samples in the laboratory. Take two 33.3 kg rubber blocks after production pressing, namely the blank sample and the test sample. Spray different types of mildew-proof agent sprays M753 (20 mL) on the surface of the test sample. According to the test conditions described in HG / T 4301-2012 Rubber Mildew-Proof Performance Test Method, place the blank sample and the test sample in an incubator. The results are shown in Table 7.

[0069] Table 7 Optimization Results of M753

[0070]

[0071] The content in Table 7 is the sum of the mass percentages of 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2(1H)-pyridinone ethanolamine salt and dodecyl dimethyl benzyl ammonium chloride, and the mass ratio of 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2(1H)-pyridinone ethanolamine salt to dodecyl dimethyl benzyl ammonium chloride is 1:4.

[0072] As can be seen from Table 7, the sum of the mass percentages of 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2(1H)-pyridoneethanolamine salt and dodecyldimethylbenzyl ammonium chloride in the preferred anti-mildew spray M753 is 50-75%, that is, the 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2(1H)-pyridoneethanolamine salt content is 10-15%, and the dodecyldimethylbenzyl ammonium chloride content is 40-60%. When the content exceeds 75%, the solubility in organic solvents deteriorates.

[0073] Example 3

[0074] The specific composition of the anti-mildew spray includes: 10% by weight of 2-octyl-4-isothiazoline-3-one and 90% by weight of propylene glycol.

[0075] Example 4

[0076] The specific composition of the anti-mildew spray includes: 10% by mass of 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2(1H)-pyridone ethanolamine salt, 40% by mass of dodecyldimethylbenzyl ammonium chloride, and 50% by mass of propylene glycol.

[0077] Example 5

[0078] The specific composition of the anti-mildew spray includes: 10% by weight of 2-octyl-4-isothiazoline-3-one, 40% by weight of dodecyldimethylbenzyl ammonium chloride, and 50% by weight of propylene glycol.

[0079] Example 6

[0080] The specific composition of the mildew inhibitor is: 2-octyl-4-isothiazoline-3-one.

[0081] Example 7

[0082] The mildew preventer is composed of 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2(1H)-pyridoneethanolamine salt and dodecyldimethylbenzyl ammonium chloride, and the mass ratio of 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2(1H)-pyridoneethanolamine salt to dodecyldimethylbenzyl ammonium chloride is 1:4.

[0083] Example 8

[0084] The mildew preventer is composed of 2-octyl-4-isothiazoline-3-one and dodecyldimethylbenzyl ammonium chloride, and the mass ratio of 2-octyl-4-isothiazoline-3-one to dodecyldimethylbenzyl ammonium chloride is 1:4.

[0085] Spray the mildew-proof spray on the test sample surfaces in Examples 3 to 5, and compare the performance changes of the raw rubber after placing it in the laboratory for 90 days.

[0086] Add 0.01 wt% (calculated based on dry rubber) of the mildew-proof agents in Examples 6 to 8 according to the actual dry rubber amount, and compare the performance changes of the raw rubber after placing the produced samples in the warehouse for 90 days.

[0087] The test results of the raw rubber performance before and after 90 days are shown in Table 8. It can be seen that there is no mildew phenomenon after using the mildew-proof spray and mildew-proof agents in the natural rubber of Examples 3 to 8, the mildew-proof grade is 0 for all, the mildew-proof effect is excellent, and the performance degradation rate of the natural rubber after the mildew-proof treatment or long-term storage does not exceed 10%.

[0088] Table 8 Test results of the raw rubber performance before and after 90 days of the mildew-proof test

[0089]

[0090]

[0091] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for preventing mildew of natural rubber, characterized in that, The specific mildew-proof agents used are 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2(1H)-pyridinone ethanolamine salt and dodecyl dimethyl benzyl ammonium chloride, and the mass ratio of the 1-hydroxy-4-methyl-6-(2,4,4-trimethylpentyl)-2(1H)-pyridinone ethanolamine salt to the dodecyl dimethyl benzyl ammonium chloride is 1:

4.

2. The natural rubber mildew-proof method according to claim 1, characterized in that The mildew-proof agent is used in the form of a mildew-proof agent spray, and the mildew-proof agent spray contains an organic solvent.

3. The natural rubber mildew-proof method according to claim 2, characterized in that, The organic solvent includes propylene glycol.

4. The natural rubber mildew-proof method according to claim 2 or 3, characterized in that, The mass content of the organic solvent in the mildew-proof agent spray is 25-90%.

5. The natural rubber mold-proof method according to claim 2, wherein Based on the size of the natural rubber being 670 mm in length, 330 mm in width, and 250 mm in height, the dosage of the mildew-proof agent spray is 10-20 mL.

Images