Polybutadiene Rubber

At present, the production technology level of the carbon black industry in the world is constantly improving and improving, but the overall development direction is still closely following the development pace of the rubber seal industry. First of all, from the scale, carbon black production companies are striving to achieve a certain scale of production, the United States is generally between (7 ~ 19) tons / year. The annual production scale capacity of China’s carbon black production enterprises has basically reached the “10,000 tons” level. From the aspect of process equipment, the United States has taken the “new process carbon black” production line based on the oil furnace method as the main force.

In recent years, from the perspective of production and technology, the direction of production process improvement includes the following aspects:

(1) Improve the structure of the reactor and increase the furnace temperature to improve quality

Oxygen-enriched air is used to add a structure regulator and an activator to the feedstock oil to increase the yield. The air preheater is used to make full use of the exhaust heat of the exhaust gas to achieve the purpose of energy saving and consumption reduction. The high-efficiency bag filter is used to reduce the dust content in the exhaust gas to a level that meets environmental requirements.

(2) Using plasma production technology

Developed by France and Norway, the use of high temperatures generated by plasma arcs accelerates the cracking of oil or other carbonaceous materials. The method has many advantages, including no combustion process, high yield of raw material carbon, and the like. The hydrogen produced can be recovered as a by-product. No toxic or harmful gases are emitted during the production process. Due to the high temperature generated by the plasma, it is advantageous for the variety of carbon black varieties.

(3) Carbon black modification treatment

The carbon black is modified by physical or chemical methods. On this basis, a new carbon black variety was developed. For example, when the carbon black irradiated by X-rays is added to the rubber, the quality of the rubber seal produced is obviously improved.

(4) Surface oxidation of carbon black

The number of oxygen-containing groups on the surface of carbon black is greatly increased, so that the surface activity and polarity are superimposed. The oxygen-containing groups can significantly improve the fluidity and pulverization of carbon black, and have the function of suppressing scorch. In addition, a similar effect can be obtained by chlorination of the carbon black surface.

(5) Surface modification of carbon black

Studies have shown that the addition of a coupling agent such as maleic anhydride to the carbon black-containing compound can improve the interaction between the carbon black and the rubber, and has an obvious modification effect. The surface grafted carbon black is used for the tread rubber, and the 300% tensile stress and tensile strength are obviously improved, and the rolling resistance is decreased. The surface graft modification method differs from the above several methods in that the modification is not carried out in the carbon black manufacturing process, but in the rubber processing.

The coloring methods of rubber grommets mainly include surface coloring and coloring of the mixture. The surface coloring is to spray the coloring agent onto the surface of the rubber grommets to color the rubber product. The method has a certain effect on static grommets. For dynamic products, the colorant is easily peeled off and easily fades. Mixing coloring is currently the main method of rubber coloring, divided into two methods: solution method and mixing method. Among them, the mixing method has several methods such as dry powder coloring, color paste coloring, pellet coloring and masterbatch coloring.

1. Solution Coloring

The method is to dissolve the rubber into a certain concentration of the solution, and then add the coloring agent and the rubber compounding agent other than sulfur to the solution, stir and mix uniformly, dry and remove the solvent at a certain temperature, and then add on the rubber mixing machine. Sulfur. The coloring method is complicated in operation, the coloring agent and the compounding agent are unevenly dispersed, the color difference is poor, the solvent is difficult to be recycled, and the environment is polluted, which has been less used at present.

2. Mixing Method Coloring

This method is currently the most commonly used method for coloring rubber grommets. The coloring agent is added directly or mixed with the carrier and then added to the rubber compound, and evenly mixed by the rubber mixing machine to color the rubber grommets. The specific method is as follows.

(1) Dry powder coloring This method directly adds the powdery coloring agent to the rubber together with the small material, and kneads it on the open mill. The method has the advantages of simple operation and low cost, but the dust is large during the mixing, pollutes the environment, and is not easy to disperse uniformly, and has a color difference. If the particles are too thick and too thick, the quality problems such as color point, stripe or chromatogram may be caused to be contaminated. It has been used less frequently. For ease of use, powdered colorants can be prepared as pre-dispersed colorants together with stearic acid, sulfates, and the like, and are commercially available.

(2) Color paste coloring method is to first mix the coloring agent with a liquid compounding agent (such as a plasticizer), grind it into a paste or a slurry by a three-roller machine, and then add it to the rubber in a certain proportion. Mixing. This method can avoid dust flying, and is also beneficial for the colorant to be dispersed in the rubber grommets and the color is uniform. However, the content of the coloring agent in the color paste is low, the coloring is not high, the transportation amount is large, the loss is large, and the user is inconvenient to use.

(3) There are two main methods for preparing the pellet coloring agent pellets. The first method is the same as other powder compounding granulation methods, in which the powdery coloring agent is first impregnated with a surfactant, and then waxed or melted and extruded with a resin to be granulated; the second method is to use a coloring agent. After the surfactant is infiltrated, the colorant particles are refined by mechanical force to form a dispersion of a certain concentration, and then mixed with the latex, and dried and then granulated. Most of the surfactants are anionic and nonionic, such as fatty acid salts, sulfonates, etc., and latex is usually a natural latex. The granular coloring agent is convenient to use, has good dispersibility, no dust flying, does not pollute the environment, has bright color, uniform hair color and no color difference, and is a promising coloring method. However, the preparation process of the granular coloring agent is complicated and the cost is limited, which limits its wide application.

(4) Masterbatch coloring This method is to mix the coloring agent, part of the plasticizer and other rubber compounding agent with the raw rubber by an open mill to prepare a colorant masterbatch with a concentration of about 50%, and then scale. Coloring is added to rubber grommets. This method is effective for coloring fine particles and difficult to disperse colorants, and has uniform color development and no color difference. Pay attention to the concentration of the colorant in the masterbatch and the amount of other compounding agents in the masterbatch.

Reprinted from：https://rubber-grommet.com/color-rubber-grommets-manufacturing-method/