Gelatin rubber is the rubber that is separated from the rubber latex by centrifugation when it is concentrated. It is made from the rubber latex by adding acid, solidifying, pressing, granulating, drying and dehydration[1]。
The content of rubber hydrocarbon in pure rubber is about 80%, and the rubber hasvulcanizationAccording to the different production processes, it can be divided into clear smoke film, clear crepe film and clear granule glue.
The rubber latex contains about 3%~7% rubber, mainly fine rubber particles, and high non rubber components[2]；In addition, it also contains: gelatin, inositol, sugar, protein, amino acid, nitrogenous base, nucleic acid, nucleoside, organic acid and inorganic salt.
AndNatural rubberIn contrast, the rubber hydrocarbon content of rubber clear rubber is lower, the rubber diameter content of rubber clear rubber is 70~85%, and the rubber diameter content of ordinary smoke film is more than 92%.The content of non rubber substances in rubber clear rubber is 2.5% and 3% higher than that in natural rubber ordinary natural rubber smoke film, respectively, while the content of acetone soluble substances and protein in rubber clear rubber is 2-4 times and 3-6 times higher than that in natural rubber.The relative density of natural rubber is about 0.95, and the content of non rubber substances in rubber rubber is very high. The relative density of non rubber substances is greater than that of rubber hydrocarbons.Therefore, the relative density of clear rubber is higher than that of natural rubber, about 0.99.Compared with natural rubber, the vulcanization rate of rubber sample is faster[3]。
In general,Natural rubberThe resilience of rubber is affected by the total amount of non rubber components. The more the non rubber content is, the worse the elasticity is. The resilience of clear rubber is worse than that of natural rubber.The content of copper and manganese ions in natural rubber is one of the main factors affecting rubber aging. There is a large amount of raw latex whey in the rubber whey.
Chemical composition
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Components
Jiaoqing Cigarette Glue/%
Gum Crepe/%
Components
Jiaoqing Cigarette Glue/%
Gum Crepe/%
rubber
seventy-three point six
seventy-three point two
ash content
nine point five four
zero point seven three
protein
eleven point four five
fourteen point two zero
Water-soluble substance
one point six six
one point four seven
Acetone extract
nine point four five
seven point nine zero
water content
one point six three
one point seven nine
Preparation type
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The whey shared during the manufacture of concentrated emulsion by centrifugation is obtained by coagulation and drying.
Depending on the compression form and drying method, it can be divided into two types: Jiaoqing cigarette glue and Jiaoqing crepe glue.This product belongs to waste liquid recycling, with small output.
Basic characteristics
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In natural rubber, it belongs to the rubber with the lowest rubber content, and its difference is very obvious.
(1) Although the rubber composition is less than 80%, andVulcanized rubberThe strength of is still high.
(2) Due to its high protein content, rubber is prone to mildew, rapid vulcanization and scorching during storage.
(3) Copper, manganese and other harmful metals in the adhesive are high and easy to age.
(4) The price is very cheap, only about 70% of the cigarette adhesive.
Research methods of clear rubber
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Basic research methods
(1) Adding strong acid: add strong acid to make it solidify. Because of the large amount of acid, the cost is high.
(2) Use deproteinization orsurface active agent Treatment of rubber: in order to improve the performance of rubber, improve the grade of goods, obtain higher recovery rate and reduce production costs.
(3) Ultrafiltration: a membrane separation process that can be classified together with reverse osmosis and microfiltration. It is treated circularly driven by pressure. Solvents and some solutes can pass through the membrane, while other components are trapped.
（4）hollow fiberPreparation of natural rubber clear rubber by column concentration method: filter out many small molecule non rubber components (such as copper, manganese, etc.), which can greatly improve the performance of clear rubber.
(5) Master rubber technology: by adding clay, carbon black, white carbon black and other nano fillers, the clear rubber is flocculated to obtain nano composite materials.
Research achievements of clear rubber at home and abroad
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(1) Acetone extraction to remove metal ions in the rubber paste:
Remove metal ions, which are catalysts for thermal oxidative degradation and will improve the thermal stability of rubber.
(2) Add a certain amount of electrolyte to assistmicrowave radiationRapid solidification of high ammonia content rubber
The clear rubber solidified by microwave radiation has higher physical and chemical properties than that solidified by sulfuric acid.The retention of most non rubber substances during the solidification process can promote vulcanization and improve the crosslinking density of rubber.
The physical and chemical properties of the raw rubber obtained can meet the requirements of domestic No. 5 standard rubber.
(4) Zeng Ying[4]The preparation process of deproteinized NR was studied
The Mooney viscosity of raw rubber can be adjusted by using a certain concentration of hydroxylamine sulfate.
(5) Latex application technology
The protein in rubber can promote rubber vulcanization and delay aging, and play a role in reinforcing.
(6) Clear rubber after deproteinization and antioxidant treatment
The raw rubber properties of the high-grade clear rubber produced meet the requirements of domestic 10 # standard rubber.
(7) Preparation of nano-SiO2/rubber composite
Effect of the dosage of nano SiO2 on nano SiOtwo/The mechanical properties of rubber rubber composites are affected, and the strength can reach 29 MPa at 10 phr.
(8) Carbon black filled rubber
Good properties can be obtained when the clear rubber is mixed with natural rubber.
(9) Clay filled rubber
First emulsify the rubber clear, then mix the clay and rubber clear evenly, solidify through acid, inorganic salt, etc. to obtain clay/natural rubber.
In terms of processing performance, it is better than natural setting and acid setting rubber.It has good anti oxygen index.
(11) Production of clear glue by aeration stripping method
The ammonia content is reduced by about 1/3, which reduces the cost of acid for coagulation by 33%, and the amount of sulfuric acid is reduced, which reduces the content of ammonia nitrogen and acid radical in the waste water of gelatine.
(12) Study on Aluminum Salt Flocculation Gelatin
useAluminium trichlorideThe residual physical and chemical indexes of the flocculated clear rubber were not significantly different from those of the ordinary clear rubber, except that the ash content was significantly higher. The mechanical properties of the flocculated rubber were better than that of the sulfuric acid coagulated rubber.
Most of the non adhesive substances are retained, and the content of ash, impurities, ash, nitrogen and volatile matter is slightly higher. The initial plastic value, oxygen resistance index and Mooney viscosity are also higher, and the mechanical properties are better than sulfuric acid gel.
(14) Manufacture of high-grade rubber with rubber
usesodium hydroxideThe anti oxygen index of rubber was improved by treating wet rubber particles to remove protein, and dipping the treated particles in sulfur gland and oxalic acid solution.
(15) Study on improving the quality of clear rubber
Use the whey stored for 24 hours to accelerate natural coagulation, and add 30-50% whey;The impurities, ash, nitrogen and other non glue substances in rubber can be greatly reduced by dialysis. After dialysis, only a small amount of oxalic acid and phosphoric acid can be used to increase the oxygen resistance index when soaking.
Scope of application
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It is generally used on lower level industrial products, often in combination with other natural orsynthetic rubberAnd adjust physical and technological properties.
Main origin
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Latex processing plants in Hainan Province, Guangdong Province, Malaysia, Indonesia, Thailand, India, etc.
Classification grade
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There are three equivalent levels of Chinese clear gum: Level I, Level II and Level III, which are roughly equivalent to the quality and price of the same level of brown crepe gum.
In recent years, as the process of cigarette sheet glue and crepe sheet glue is gradually transformed into the production mode of standard glue, the clear glue is also changed into granular glue.Due to the poor aging resistance of the adhesive, it is easy to mildew and deteriorate in storage, and is now rare in the international market.It is mainly used as a by-product of the production of natural rubber latex concentrated by centrifugal method, and is comprehensively utilized[6]。
