On the basic production process of rubber products

- Oct 12, 2018-

[rubber technical net - processing technology]

With the rapid development of modern industry, especially chemical industry, there are many kinds of rubber products, but their production process is basically the same.

With the general solid rubber (raw rubber) as the raw material products, its production process mainly includes: raw material preparation, plastication, mixing, molding, vulcanization, recuperation, test

Rubber products, materials,

1 basic technological process

With the rapid development of modern industry, especially chemical industry, there are many kinds of rubber products, but their production process is basically the same.

The production process of general solid rubber (raw rubber) mainly includes:

Raw material preparation - plastication - mixing - molding - vulcanization - healing - testing

2 preparation of raw materials

The main materials of rubber products are raw rubber, compound, fibre and metal.

The raw glue is the basic material.

The compound is an auxiliary material added to improve some properties of rubber products.

Fiber materials (cotton, linen, wool, various man-made fibers, synthetic fibers) and metal materials (steel wire, copper wire) are used as the framework of rubber products to enhance mechanical strength and limit product deformation.

In the preparation of raw materials, ingredients must be weighed accurately according to the formula.

Some materials need to be processed in order to make the raw glue and the coordination agent mix evenly with each other:

Raw rubber in 60-70 ℃ after baking chamber in soft, gel and gel breaking into pieces; cut again

Blocky complexes such as paraffin, stearic acid, rosin, etc. should be crushed;

If the powder compound contains mechanical impurities or coarse grains, it needs to be screened out.

Liquid complexes (pine tar, gumalone) need to be heated, melted, evaporated water and filtered impurities.

The dosages should be dried, otherwise it is easy to agglomerate and the old ones cannot be dispersed evenly during mixing. Bubbles will be generated during vulcanization, thus affecting product quality.

3 the molding

The raw glue is elastic and lacks the necessary property (plasticity) during processing, so it is not easy to process.

In order to improve its plasticity, it is necessary to plasticize the raw rubber.

In this way, when mixing agent is easy to disperse evenly in the raw glue;

At the same time, it also helps to improve the permeability (infiltration into the fabric) and forming fluidity in rolling and forming process.

The process of forming plasticity is called plastication.

There are two methods of plastication: mechanical and thermoplastic.

Mechanical plastication is a process in which long chain rubber molecules undergo degradation and transformation from high elastic state to plastic state through mechanical extrusion and friction action of the plasticator at not too high temperature.

Thermoplastic refining is the injection of hot compressed air into the raw glue. Under the action of heat and oxygen, long chain molecules are degraded and shortened, so as to obtain plasticity.

4 mixed

In order to adapt to various conditions of use, obtain various properties, and also to improve the performance of rubber products and reduce the cost, it is necessary to add different additives in the raw glue.

Mixing is a process in which the plasticated raw glue is mixed with the compound agent and put in the mixing machine.

Mixing is an important process in the production of rubber products. If the mixing is not uniform, the role of rubber and coordination agent cannot be fully played and the performance of the product can be affected.

The gum that gets after mixing, people calls mix gum, it is the semifinished product material that makes all sorts of rubber product, common name is glue makings, usually all sell as a commodity, purchaser can use glue makings direct processing to shape, vulcanization makes the rubber product that needs.

According to the different formulation, mixed rubber has a series of performance of different brands and varieties, to provide choice.

5 the molding

In the production of rubber products, the use of calendering machine or extruder pre-made shape of various, different sizes of the process, known as molding.

Methods of forming include:

Rolling molding is suitable for manufacturing simple sheet and sheet products.

It is the mixing of rubber through the rolling machine into a certain shape, a certain size of film is called rolling molding.

Some rubber products (such as tires, rubber cloth, rubber tube, etc.) used textile fiber materials, must be coated with a thin layer of glue (also known as sticking or rubbing on the fiber), the process of coating is also generally completed on the calender.

Before calendering, the fiber material needs to be dried and soaked with glue. The purpose of drying is to reduce the moisture content of the fiber material (to avoid water evaporation and foaming) and improve the temperature of the fiber material, so as to guarantee the quality of calendering process.

Impregnation is the necessary process before gluing. The purpose is to improve the binding performance of fiber material and glue material.

Extrusion molding is used for more complex rubber products, such as tire tread, rubber tube, metal wire surface coating rubber need to be produced by extrusion molding.

It is a method of continuous molding through various mouth shapes (also called templates) by placing the mixed rubber with certain plasticity into the hopper of the extruder under the extrusion of the screw rod.

Before extruding, the rubber material must be preheated to make the material soft and easy to extrude.

Moulding can also be used to produce some rubber products with complex shapes (such as skin bowl and sealing ring) by moulding. With the help of moulding Yin and Yang moulds, the rubber materials can be placed in the moulds and heated to shape.

6 sulfide

Called plastic rubber into the process of elastic rubber vulcanization it is to a certain amount of curing agent such as sulphur, vulcanization accelerator join the semi-finished products made from raw rubber in the prescribed temperature vulcanizing tank heating, heat preservation of raw rubber linear generated by sulfur "bridge" between the molecules and got behind each other hand in 3 d mesh structure making plastic rubber vulcanizates with high elasticity.

Because the crosslinked bond is mainly composed of sulfur, it is called "vulcanization".

With the rapid development of synthetic rubber, there are many varieties of vulcanizing agents besides sulfur, such as organic polysulfide, peroxide and metal oxide.

Therefore, the process of transforming linear plastic rubber into three-dimensional network elastic rubber is called vulcanization. Any material that can bridge the rubber material is called vulcanization agent.

The elastic rubber after vulcanization is called vulcanized rubber or soft rubber commonly known as "rubber".

Vulcanization is one of the most important process of rubber processing.

Unvulcanized rubber is of little use value in use, but the degree of under-sulphur vulcanization is insufficient to reach the maximum curing time.

Therefore, it is necessary to strictly control the curing time in the production process to ensure that the vulcanized rubber products have the best performance and the longest service life.

7 auxiliary measures

In order to achieve operational performance, additional measures should be added in the production process

1. Increase strength -- phenolic resins mixed with hard carbon black

2. Increase wear resistance -- match hard carbon black

3. High air tightness requirement -- use less volatile components

Increase heat resistance -- new curing process

5. Increase cold resistance -- reduce the tendency of crystallization by using low temperature plasticizer through unbranched inlay of raw glue

6. Increase flame resistance -- no use of flammable auxiliaries, use less softeners, and use flame retardants such as antimony trioxide

7. Increase oxygen resistance and ozone resistance -- adopt diamine protective agents

8. Improve electrical insulation -- match high structure filler or metal powder with antistatic agent

9. Improve magnetic properties -- use strontium iron oxide aluminum nickel iron powder iron barium powder as filler

10. Improve water resistance -- use lead oxide or resin curing system to mix filling agents with lower water absorption, such as barium sulfate and clay

11. Improve oil resistance -- full cross-linking and less use of plasticizers

Increase ph and alkali resistance -- multi-purpose filler

Improve the high vacuum properties -- use less volatile additives