CN106565862A - Natural latex ammonia-free preservative and preservation method thereof - Google Patents

Abstract

The invention discloses a natural rubber latex ammonia-free preservative and a preservation method, which improves the disadvantages of polluting the environment, corroding buildings, and endangering the health of workers during the use of commonly used ammonia water. The preservative is characterized in that the pH value is 8.0-9.5, the density is 1.02-1.08g/Ml, it is easily miscible with oil and water, and it is difficult to volatilize. Its main component is morpholine derivatives, which can be stored and transported at room temperature. It can be used directly without special treatment. With a content of 0.3%, this kind of preservative can effectively preserve natural latex for not less than 60 hours. Compared with latex preserved with the same content of ammonia water, it has the characteristics of low volatile fatty acid value, low pH value drop rate, and strong antibacterial effect. The preservation effect of the preservative of the invention is better than that of ammonia water in preserving natural rubber latex within 60 hours, the raw rubber meets the requirements of No. 5 standard rubber, the structure is not affected, and the vulcanized rubber has excellent comprehensive performance.

Description

A kind of natural latex ammonia-free preservative and preservation method thereof

technical field

The invention relates to the field of natural rubber processing, in particular to a natural latex ammonia-free preservative and a preservation method.

Background technique

Natural rubber latex is a renewable resource and an important industrial raw material in the world. Its excellent comprehensive properties make it widely used in the rubber industry. The main component of natural rubber is homeopathic polyisoprene, and contains 5%-7% non-gum substances, such as sucrose, protein, inorganic salts, etc.

Natural rubber latex is easily corrupted and deteriorated by the action of bacteria, enzymes and metal ions, and phenomena such as stickiness, discoloration and odor change appear, which seriously affect the quality of the product. In order to ensure the performance of the product, a certain amount of preservative should be added to the natural latex during the collection, transportation and storage to ensure the stability of the latex.

After years of hard work by domestic and foreign scientific researchers, sodium pentachlorophenate, methylamine, hydroxylamine, sodium carbonate, formaldehyde, chitosan, triazine derivatives, etc. have emerged as natural rubber latex preservatives. Considering the effect, toxicity, cost and other aspects, the factory still uses commonly used ammonia water as the natural latex preservative.

As a latex preservative, ammonia water can inhibit the division and reproduction of bacteria, increase the negative charge on the surface of rubber particles, and enhance the stability of latex. , It is volatilized and wasted during use, and its alkalinity will also cause corrosion and damage to buildings and the environment, and more seriously, it will endanger the health of processing workers.

In order to improve the working environment of workers, avoid building corrosion, and reduce production costs, it is imperative for the latex industry to find a novel natural latex preservative and preservation method.

Contents of the invention

The purpose of this invention is to provide a kind of natural latex ammonia-free preservative and preservation method thereof, overcome the shortcoming of commonly used ammonia water preservative, improve the preservation time of natural latex, improve the workman's working environment.

The natural latex ammonia-free preservative of the present invention is a kind of morpholine derivative.

In the present invention, 1g-5g of the preservative prepared in advance is added to 1000mL of freshly collected natural rubber latex, stirred slowly for 1 minute until uniformly mixed, and the performance index of the latex with the same storage interval at normal temperature is detected.

In the present invention, 3 g of the preservative is added to 1000 mL of freshly collected natural latex, stirred slowly for 1 minute until uniformly mixed, stored at room temperature for 60 hours, and then the natural latex preserved by the preservative is processed into raw rubber.

The invention tests the six indexes of the raw rubber and the structural change of the natural latex preserved by the preservative, and simultaneously tests the mechanical properties of the vulcanized rubber. The results show that the six indexes of raw rubber meet the requirements of No. 5 standard rubber, the structure does not change, and the vulcanized rubber has excellent performance.

When the natural rubber latex of the present invention has an ammonia-free preservative content of 0.3%, the natural rubber latex can be effectively preserved for 60 hours.

The natural rubber latex ammonia-free preservative of the invention has the characteristics of miscibility with water, low volatility, no irritating smell and the like.

The invention effectively solves the problems of weak sterilizing ability of ammonia water, polluting the environment, corroding buildings and the like.

detailed description

Example 1

Take 1-5g of the pre-prepared preservative and add it to 1000mL of freshly collected natural latex, stir slowly for 1 minute until the mixture is uniform, and check the volatile fatty acid value of the latex every 12 hours until the storage time is 60 hours. The test of volatile fatty acids is in accordance with GB/T8292-2008 standard.

Example 2

Take 2.4g of the preservative prepared in advance and add it to 800mL of freshly collected natural rubber latex, stir slowly for 1 minute until the mixture is uniform, store it at room temperature for 60 hours, add 0.2% y acetic acid to solidify it, mature it for 12 hours, and then process it into natural latex by dehydration and drying. Glue, test its six indicators.

Example 3

Get 200g of raw rubber processed by Example 2 to be vulcanized and cut into pieces to make a standard sample for mechanical testing. Take some standard samples and age them at 100°C for 24 hours. The mechanical properties of the samples before and after aging were tested using a tensile testing machine. The mechanical test is in accordance with GB/T528-2009 standard.

Table 1 The volatile fatty acid values of natural rubber latex preserved in different time content and different preservatives

Table 2 Changes of physical and mechanical properties of vulcanizate before and after aging

As can be seen from the volatile fatty acid value in Table 1, the more the content of the natural latex ammonia-free preservative of the present invention, the lower the volatile fatty acid value of the latex, and the better the preservation effect. When the preservative content is 0.3%, the natural latex can be effectively preserved without deterioration for 60 hours. At this time, the volatile fatty acid value of the latex is 0.066, while the volatile fatty acid value of the latex preserved with ammonia water is 1.179. Experiments have shown that within 60 hours of natural latex preservation, the preservation effect of 0.3% natural latex ammonia-free preservative on latex is better than that of ammonia water with the same content.

From the physical and mechanical properties of the vulcanized rubber in table 2 before and after aging, it can be seen that the tear strength, tensile strength, and elongation at break of natural rubber latex produced by latex without ammonia preservative are all higher than the ammoniacal liquor control group, illustrating that this method of the present invention A kind of natural latex ammonia-free preservative and preservation method has room for development.

Claims (5)

1. a kind of Heveatex is without ammonia preservative agent and store method, it is characterised in that for a kind of morpholine analog derivative.

2. the Heveatex according to right 1 is without ammonia preservative agent and store method, it is characterised in that the preservative agent is Heveatex using content（Weight in wet base）0.1%-0.5%.

3. Heveatex according to claim 2 is without ammonia preservative agent and store method, it is characterised in that this kind of preservative agent is directly added into freshly harvested Heveatex, is slowly stirred 1 minute to being well mixed.

4. Heveatex according to claim 3 is without ammonia preservative agent and store method, it is characterised in that contain the container of Heveatex through ethanol sterilization processing.

5. Heveatex according to claim 2 is without ammonia preservative agent and store method, it is characterised in that freshly harvested Heveatex addition preservative agent preserves 60h, is solidified with 2% acetic acid, cures 12-18h, cleans, is dehydrated creped and is dried, and is prepared into rubber.