Molded Rubber Parts Are Moulded Parts That Are Pressed By a Flat Vulcanizer Under The Specified Time, Pressure And Temperature Conditions By Placing The Mixed Rubber Blank In The Model.
Rubber Molded Parts Main Raw Materials Are Raw Rubber, Various Compounding Agents, And Fiber And Metal Materials As Skeleton Materials. The Basic Production Process Of Rubber Parts Includes Six Basic Processes: Plastic Refining, Mixing, Calendering, Extrusion, Forming And Vulcanization.
Rubber Parts Processing Process Of Is Mainly The Process Of Solving The Contradiction Between Plasticity And Elasticity. Through Various Processing Means, The Elastic Rubber Is Transformed Into Plastic Rubber, And The Semi-Finished Products Are Made By Adding Various Compounding Agents, And Then The Semi-Finished Products With Plasticity Are Transformed Into Rubber Parts With High Elasticity And Good Physical And Mechanical Properties Through Vulcanization.
1, Basic Process Flow
There Are Many Kinds Of Rubber Products, But The Production Process Is Basically The Same. The Basic Process Of Rubber Products With General Solid Rubber As Raw Rubber Includes 6 Basic Processes: Molding, Mixing, Calendering, Pressing, Molding And Vulcanization. Of Course, Raw Material Preparation, Finishing, Inspection, Packaging And Other Basic Processes Are Indispensable. The Processing Technology Of Rubber Is Mainly To Solve The Contradictory Process Of Plasticity And Elastic Properties. Through Various Technological Means, The Elastic Rubber Is Made Into Plastic Plastic Rubber, And Then a Variety Of Compound Agent Is Added To Make The Semi-Finished Product, And Then The Plastic Semi-Finished Product Is Turned Into Rubber Products With High Elasticity And Good Physical And Mechanical Properties By Vulcanization.
2, Preparation Of Raw Materials
1>The Main Raw Materials For Rubber Products Are Raw Rubber As The Basic Material, And The Raw Rubber Is Collected By Artificial Cutting Of Bark On The Rubber Tree Of The Tropical And Subtropical Regions.
2>All Kinds Of Additives Are Auxiliary Materials To Improve Some Properties Of Rubber Products.
3>Fiber Materials (Cotton, Linen, Wool And Various Artificial Fibers, Synthetic And Metal Materials, Steel Wire) Are The Skeleton Materials Of The Rubber Products To Enhance The Mechanical Strength And Limit The Variant Of The Products. The Ingredients Must Be Accurately Weighed According To The Formulation In The Raw Material Preparation Process. In Order To Make The Raw Rubber And The Compounding Agent Mix Evenly, It Is Necessary To Process The Materials. The Raw Rubber Should Be Dried In The Drying Room At 60–70 C And Then Cut Into Glue And Broken Into Small Pieces. Such As Paraffin, Stearic Acid, Rosin And So On To Be Crushed. If The Powder Contains Mechanical Impurities Or Coarse Particles, It Needs To Be Screened Out Of Liquid, Such As Loose Tar, Ancient Malone Needs Heating, Melting, Evaporation Of Water, Filtering Impurities.
3, Raw Rubber Is Elastic And Lacks The Plastic Properties Necessary For Processing. Therefore, It Is Not Easy To Process. In Order To Improve Its Plasticity, It Is Necessary To Plastic The Raw Rubber So That The Mixture Is Easily Dispersed In The Raw Rubber In The Mixing Process, And In The Process Of Calendering And Molding, It Also Helps To Improve The Permeability Of The Adhesive Into The Fabric And Molding Fluidity. The Process Of Degrading The Long Chain Molecules Of Raw Gum Into Plasticity Is Called Plasticization. There Are Two Ways To Produce Raw Rubber, Namely, Mechanical Plasticization And Thermoplasticization. The Mechanical Extrusion Of Mechanical Plastic Is To Shorten The Molecular Degradation Of Long Chain Rubber From The High Elastic State To The Plastic State By The Mechanical Extrusion And The Friction Force Of The Plastic Mill At The Low Temperature. Thermoplasticization Is The Introduction Of Hot Compressed Air Into The Raw Rubber, Which Reduces The Degradation Of Long Chain Molecules Under Heat And Oxygen, Resulting In Plasticity.
4, Mixing
In Order To Adapt To a Variety Of Different Use Conditions, Obtain a Variety Of Different Properties, And To Improve The Performance Of Rubber Products And Reduce Cost, It Is Necessary To Add Different Additives In The Raw Rubber. Mixing Is a Process Of Mixing The Plastic Raw Rubber With The Mixture, And Dispersing The Compound In The Raw Rubber Completely And Evenly Through The Mechanical Mixing In The Rubber Machine. Mixing Is An Important Process In The Production Of Rubber Products. If The Mixture Is Not Uniform, It Can Not Give Full Play To The Effect Of Rubber And Mixture On The Performance Of The Product. After Mixing, The Rubber Is Called Mixed Rubber. It Is a Semi Finished Material For Making Various Kinds Of Rubber Products. It Is Commonly Known As The Rubber Material Is Usually Sold As a Commodity And The Buyer Can Make Use Of The Rubber To Make The Rubber Products Directly And Vulcanized. According To The Formula? Mixing Rubber Has a Series Of Different Brands And Varieties With Different Properties.
5, Molding
In The Production Process Of Rubber Products, Calender Or Extruder Is Used To Make Various Processes With Different Shapes And Sizes. The Molding Methods Are
1. Calendering
It Is Suitable For The Manufacture Of Simple Sheet And Plate Shaped Products. It Is Called The Calender Forming Method That Compacts The Glue Through a Calender To Form a Certain Shape Or a Certain Size Of The Film. Some Of The Rubber Products, Such As Tires, Rubber Cloth And Hose, Must Be Coated With a Thin Layer Of Glue On The Fiber, Called Glue Or Rubbing, And The Coating Process Is Usually Done On a Calender. The Purpose Of The Fiber Material To Be Dried And Soaked Before The Calendering Is To Reduce The Moisture Content Of The Fiber Material In Order To Avoid The Evaporation Of Water, And To Improve The Temperature Of The Fiber Material To Ensure The Quality Of The Calendering Process. Dipping Is a Necessary Process Before Hanging Glue. The Purpose Is To Improve The Binding Property Of Fiber Material To Rubber Compound.
2. Extrusion Molding
For More Complex Rubber Products, Such As Tire Tread, Rubber Hose And Metal Wire Surface Coating, It Needs To Be Manufactured By Extrusion Molding. It Is a Method To Make a Certain Plastic Mixture In The Extruder’s Hopper’s Inner Screw Extruding Through a Variety Of Mouths. Before Extrusion, The Rubber Must Be Preheated To Make The Rubber Soft And Easy To Squeeze, So That The Rubber Products With Smooth Surface And Accurate Size Can Be Obtained.
3. Molding
It Is Also Possible To Use The Molding Method To Make Some Rubber Products With Complex Shapes Such As Leather Bowl And Seal Ring.
6, Vulcanization
The Process Of Converting Plastic Rubber To Elastic Rubber Is Called Vulcanization. It Is Added To a Certain Amount Of Vulcanizing Agents, Such As Sulphur, Vulcanization Accelerant, Etc. Into Semi Finished Products Made Of Raw Rubber, To Be Heated And Insulated At a Specified Temperature In a Vulcanized Tank To Make The Linear Molecules Of The Raw Rubber Cross Cross Into a Three-Dimensional Network By Generating a “Sulfur Bridge”. The Structure Makes The Plastic Rubber Become a Vulcanizate With High Elasticity. Since Crosslinking Bonds Are Mainly Composed Of Sulphur, They Are Called “Vulcanization”. With The Rapid Development Of Synthetic Rubber, There Are Many Kinds Of Vulcanizing Agents Besides Organic Sulfur, Peroxide, Metal Oxides And So On. Therefore, The Process Of Converting Plastic Rubber To Three-Dimensional Reticulated Elastic Rubber Is Called Vulcanization. The Vulcanized Rubber After Vulcanization Is Called Vulcanized Rubber, Also Called Soft Rubber, Commonly Known As “Rubber”. Vulcanization Is One Of The Most Important Processes In Rubber Processing. All Rubber Products Must Undergo Vulcanization To Achieve The Desired Performance. The Unvulcanized Rubber Is Of No Use In Use, But The Degree Of Sulphur Vulcanization Is Not Enough, The Failure Time Is Not Enough To Reach The Best State And The Sulfuration Time Is Over, And The Performance Decreases Significantly, And The Rubber Performance Is Reduced. Therefore, The Curing Time Must Be Strictly Controlled In The Production Process To Ensure That The Vulcanized Rubber Products Have The Best Service Performance And The Longest Service Life.
7, Auxiliary Measures
Auxiliary Measures Should Be Added To The Production Process In Order To Achieve Service Performance.
1. Increase Strength — Use Hard Carbon Black And Phenolic Resin.
2. Increase Wear Resistance – Use Hard Carbon Black
3. High Gas Tightness Requirements – Less Volatile Components.
4. Increase Heat Resistance – a New Vulcanization Process
5. Increase The Cold Tolerance By Decreasing The Crystallization Tendency Of The Raw Rubber By Using The Branch Breaking Of Raw Rubber, And Using Low Temperature Plasticizer.
6. Increase Fire Resistance – No Combustible Additives, Less Softeners, And Use Of Flame Retardants Such As Three Antimony Oxide.
7. Increase Oxygen Resistance And Ozone Resistance — Use Of Two Amine Protectant
8. Improve Electrical Insulation – Use Of High Structure Filler Or Metal Powder With Antistatic Agent.
9. Improve Magnetism – Use Strontium Iron Oxide Aluminum Nickel Iron Powder Iron Barium Powder As Filler.
10. Improve Water Resistance. Use Lead Oxide Or Resin Vulcanization System To Fill Low Water Absorbent Such As Barium Sulfate And Clay.
11. Improve Oil Resistance – Full Crosslinking And Less Plasticizer.
12. Increase Acid Alkalinity – Multipurpose Filling Agent
13. Improve High Vacuum – Use Volatile Additives.
