Now come up with this formula to communicate, one is to wish everyone a happy work, the other is I also want to let others find problems, we can get greater improvement together!

This is a low-grade cattle cloth rubber shoes outsole formula, there are still a lot of workers in the production and use. For example, according to the pure theoretical point of view of modern rubber products, this is an irrelevance and a recipe full of loopholes. However, according to the actual situation and the actual situation of low-grade products, it can be said that it is a very good and practical formula, which contains rich theoretical knowledge and the essence of extensive practical experience. It also involves vulcanization process, shoe-making process, effective cost reduction and maximum productivity improvement. Please don't look down on this rotten formula, I think it also contains the flexible use of rubber formula technologists wisdom crystallization. It is a formula that was born under many harsh conditions. It uses the advantages of technology, process and equipment to make up for the defects in the formula, and creates a balance point under unbalanced conditions to achieve stability in production. Although this is the case, there are still many Inadequacies, there are certain hidden dangers. The formula is as follows,

1.NR 50  

2，SBR 50  

3，S 2  

4，DM2.3  

5,M 2.0

6，TMTD 0.5 

7,SA 3

8，ZNCO3  6   

9, white carbon black 75

10, diethylene glycol 7.5

11, white oil, 45

12 cow-made mother glue 0.2.

13. Antifogging agent 0.8

14., Dispersants, 1.5

Set the vulcanization temperature of 170 degrees (steam pressure 7-8KG), vulcanization time is 150 seconds, the necessary conditions are:

1, curing time 150 seconds,

2. Transparent cow bottom.

3, the cost can not be too high,

4, aging quality three to five months.

5. Has good adhesive properties.

The basic process is vulcanized cloth rubber shoes, molded bottom secondary vulcanization, primary vulcanization and secondary vulcanization time within 48 hours, secondary vulcanization with a vulcanizing tank.
 

First of all, according to the high-grade shoe-making concept to analyze, as the rubber material of the outsole is often the pursuit of physical properties, wear resistance, slip resistance, with a certain tear strength, good adhesive properties, with appropriate anti-aging properties and a certain degree of elasticity, cattle bottom also need a certain degree of transparency.

If this formula is analyzed according to this concept; First of all, the main rubber is matched, which looks very unreasonable on the surface. The wear resistance of the combination of natural rubber and styrene-butadiene rubber cannot achieve the best wear resistance in general-purpose rubber. The vulcanization speed of the two rubbers is too different. Co-vulcanization requires a long vulcanization time. It is often that the natural rubber is over-sulfur, the styrene-butadiene rubber is still under-sulfur, and the elasticity is poor. In order to achieve co-vulcanization, it is necessary to increase the amount of accelerator, which will cause serious blooming hazards. From the point of view of vulcanization temperature and time, there is also great irrationality. From the point of view of temperature, the most suitable temperature for natural rubber is 143 degrees but not more than 150 degrees, otherwise it will return to the original, depolymerization, etc., resulting in poor physical properties.

In terms of vulcanization time, only 150 seconds to achieve co-vulcanization is too short for styrene-butadiene rubber, unless a large amount of accelerator is added, which in turn risks blooming. And the cost of natural rubber on the market is still high, and the amount is too high. However, medium and high-grade formulations are based on cis-butyl as the main glue, with natural, butyl benzene to improve the process performance. The use of butyl rubber has superior wear resistance and elasticity as the main glue, the use of natural rubber to improve the tensile force, slip resistance and adhesive strength, with styrene butadiene rubber to improve comprehensive performance and anti-aging performance.

The vulcanization system is sulfur vulcanization system, and the accelerator is thiazole and thiuram. This is a commonly used vulcanization system. The dosage of sulfur is relatively normal, but the dosage of accelerator is too high, especially the concentration of accelerator M and DM is far beyond the solubility of rubber. The risk of frost spraying is inevitable. The dosage of stearic acid is a little higher than 3 parts, and there is also the risk of spraying. The dosage of zinc carbonate is no problem. But in general, 4.5 parts can be used.

The dosage of silica in the reinforcing system reaches 75 parts, which is obviously too much. Under normal circumstances, if high hardness is not pursued, the physical properties of the dosage exceeding 60 parts will decrease. Diethylene glycol is used in 7.5 parts to improve the affinity of silica and rubber, and is alkaline, can activate the acid accelerator, can appropriately reduce the amount of accelerator, help to adjust the vulcanization speed. Normal dosage of 6 parts is enough.

The softening oil is used in 45 parts, which is basically a filling oil and is mainly used to reduce the cost. The physical properties are definitely reduced. And it is not conducive to the aging properties of rubber, and its softening oil will continue to migrate to the surface after vulcanization. After a long period of time, the hardness of the bottom will increase significantly. Because the amount of oil is too high, the balance of the major coordination system of the formula is broken.

Due to the high amount of natural rubber, easy to stick to the roller, a small amount of anti-fog wax is mainly used to improve the process performance, the dispersant is suitable for the mixing process of the dense mill, which is helpful for the dispersion of the compounding agent. The anti-aging agent is not added, mainly according to the anti-aging requirements of the product and the matching status of the formula, which is more practical.

This is according to the rubber formula, and high-grade shoe-making concept of the formula, the formula of the five with the system is obviously unbalanced, there are serious defects.

However, the analysis of this formula according to the actual situation of the factory is another situation. This product is a cloth rubber shoe outsole, which is a low-grade product in the footwear industry. The first thing to test is to reduce the formula cost when the physical property allows.

Formula comments are as follows:
 

This product is a translucent beef bottom, which limits the addition of fillers such as reclaimed rubber, rubber powder and various stone powders. All compounding agents should consider the removal rate, so it is natural to fill a large amount of white carbon black and white oil. The relative cost of these two compounding agents is much lower than that of rubber, and it is also an effective means to reduce costs. Silica is hydrophilic, it will absorb the OH group of the accelerator, so that the vulcanization speed is slow, the rubber becomes hard, white oil is acidic, it will delay the activation energy of the accelerator. This is disadvantageous for fast vulcanization systems. The addition of a large amount of filling oil will continue to reduce the volume cost of the rubber compound, help the dispersion of white carbon black in the rubber compound, reduce the hardness of the rubber, thin flash of the product, good fluidity of the rubber compound, reduce the rubber content of the product, and also reduce the formulation cost. However, a large amount of filling oil will make the product break through the three-dimensional network structure of rubber and migrate to the surface of rubber continuously after vulcanization, and the sole will slowly harden, aging properties deteriorate and seriously affect the adhesive properties of the compound.

In the case of unbalanced formula, it is useless to add any antioxidant, so how to choose the main rubber in the formula is more important. 50 parts of styrene butadiene rubber and 50 parts of natural rubber are acceptable. Because relatively speaking, styrene butadiene rubber has comprehensive mechanical properties and contains styrene with good anti-aging performance, so its aging performance is better than that of general natural rubber and cis-polybutadiene rubber, it is reasonable to choose 50 parts of styrene-butadiene rubber when the antioxidant has little effect. In addition, the solubility of styrene-butadiene rubber to oil is relatively large, which can reduce the phenomenon of oil injection.

It is natural to use more than 50 parts, but it is no problem. Because a large number of softening oil migration will affect the adhesive performance, natural rubber to the adhesive paste (permeability) strong adhesion, increase the amount will help the adhesive strength, slip resistance and tension.

Due to the objective conditions of the factory and the grade of the product, the consideration of production efficiency must be put in the first place, so the setting of curing time of 150 seconds must be positioned. In this way, it is difficult to reasonably design the vulcanization system, because the vulcanization speed of styrene-butadiene rubber is quite slow, and the natural sulfur speed is quite fast, and their vulcanization speed is almost half of the difference. In this way, it is quite difficult to achieve co-vulcanization of rubber in such a short period of time. The only way is to increase the amount of accelerator to improve the vulcanization speed. However, excessive increase in the amount of accelerator will cause the possibility of blooming of rubber products. Therefore, it is the only way to reduce the amount of accelerator by increasing the vulcanization temperature. Therefore, setting the 170-degree vulcanization temperature is natural, because the temperature is already very high, natural rubber is likely to be depolymerized, that is, physical properties will also affect the vulcanization of the product.

On the other hand, the amount of diethylene glycol is increased to improve the activity of the accelerator. For example, 6 parts are enough according to the normal formula, but 7.5 parts are still used in this formula. For example, the amount of diethylene glycol can be increased to increase the vulcanization speed and the activity of the accelerator. Reduce the amount of accelerator, but the crosslinking density will be significantly reduced, so that the soft physical and mechanical properties of the product have a certain decline.

Nevertheless, the amount of accelerator used to achieve full vulcanization of the styrene-butadiene rubber within 150 seconds is considerable. Among them, the dosage of DM and M still exceeds the solubility of rubber. In order to reduce the risk of blooming, the dosage of stearic acid is increased. Stearic acid will also be sprayed to the surface if the dosage is increased in other general-purpose rubbers. However, due to the large solubility of styrene-butadiene and natural rubber to stearic acid, increasing the dosage of stearic acid can dissolve some accelerators in stearic acid, to reduce the risk of accelerant ejection. In addition, 1.5 parts of dispersant can further improve the dispersion of the rubber compound, reduce the local concentration of the accelerator is conducive to reducing the frost spray, and most of the dispersant is a mixture of fatty acids, but also can dissolve a part of the excess accelerator. Therefore, the overall formula system is much less likely to spray cream as long as it is not sulfur-deficient. rubber technology network of friends to see here should understand some of.

Although there will still be a small amount of blooming in the daily production of this formula, the main reason is that the accelerator concentration of the whole formula is still too high, it can be completely controlled as long as the production process is properly matched, because the production process of cloth rubber shoes is to vulcanize the bottom of the steel, and after a period of time, it needs to be vulcanized twice in the vulcanization tank, even if there is a slight lack of sulfur after secondary vulcanization, it can still achieve complete crosslinking. Then reducing the parking time of the outsole will help reduce the frost spray phenomenon. Frost spray always takes a period of time to slowly move to the surface, even if it is not sulfur, it can be avoided as long as it is sent to the vulcanization tank before moving to the surface.

The unvulcanized rubber must be practiced on the production machine before molding vulcanization, which will help reduce the frost spray. Because the unvulcanized rubber after adding sulfur after a period of time, its compounding agent will slowly move to the surface, if not back to practice, it is likely to make the surface concentration of the rubber accelerator is too high, after vulcanization will migrate to the surface. The sole is parked for too long, and a part of the compounding agent in the undersulfur rubber outsole that does not reach the positive vulcanization point will break through the network structure of the rubber and migrate to the surface of the rubber, resulting in blooming.

A small amount of sulfur deficiency in daily production is very likely, and there are many factors:

1. If the vulcanization temperature is too low due to unstable boiler steam pressure, for example, 6.5-8KG, their temperature difference is 10 degrees, then the vulcanization speed at high steam pressure can be twice as fast as that at low steam pressure.

2. Sulfur chemical industry has not reached the time to open the mold during molding,

3. Inaccurate weighing during batching and uneven dispersion during batching will cause sulfur deficiency to varying degrees. Because the concentration of the accelerator in the rubber is too high, the hidden danger of frost spraying always exists. The way to eradicate it is not only to prevent the rubber from lacking sulfur, but also to adjust the formula to reduce the concentration of the accelerator.

This formula is a typical formula of the 1980 s, which can be said to be a relatively good formula. However, there is still a lot of room for improvement, which can be combined according to the traditional advantages and modern formula theory, and the cost can continue to be reduced while keeping the physical properties of the original formula unchanged. For example, the matching of the main rubber can reduce the appropriate amount of natural rubber, styrene-butadiene rubber and the appropriate amount of cis-polybutadiene rubber. The vulcanization accelerator can be increased from three kinds to four kinds to achieve the purpose of reducing the concentration of the accelerator. The filler can be appropriately added with magnesium carbonate or bovine rubber powder to reduce the cost. After adding fillers, the physical properties may decrease, which can be improved by coupling agent.

As long as the formula is adjusted reasonably, after a large number of tests, this formula can theoretically continue to reduce costs without affecting physical properties. In order to make the formula of this high-speed fluidization system more stable, it is completely possible to adjust the formula, but it is still difficult. As long as the formula, process and process are adjusted in a trinity, some new compounding agents are added to reduce the amount of accelerator. I think it is still possible to completely eradicate the hidden dangers of frost spraying. As long as the formula with the lowest cost to make the highest physical properties and good processing performance is the best formula when it is recognized by the market.