Rubber Basics Introduction • Popular definitions:
• rubber is a highly elastic polymer compounds (molecular weight of 10 million or more in general), so they have no other materials are highly elastic. Thus, also known as elastomers.
 
• Rubber origins:
• by native tropical American tree crying tears dried emulsion solidified.
 
• Development:
• curing method of the invention.

Classification of rubber
• Natural rubber and synthetic rubber.
• a: natural rubber
• As the name suggests, is made from natural or planted rubber trees after tapping, filter cleaning. Drying processes processing.
 
II: synthetic rubber
 
• The pyrolysis oil were then chemically synthesized
 
• synthetic rubber Category:
 
• A generic class: that meet the general requirements of the rubber.
 
• B special synthetic class: to meet the special requirements of the rubber.
General synthetic rubber used include:

• 1 SBR:. (SBR)
• butadiene \ styrene earliest synthesized rubber elastic somewhat less than NR, wear and aging better than NR, mainly used for shoe soles and tires.
• 2. Isoamyl rubber (IR)
• isoprene because NR same structure, it is also known as artificial NR. NR similar nature.
• 3. Butadiene rubber (BR)
• butadiene its elasticity and low temperature resistance is the best general-purpose rubber for tires, jumping ball.
Special synthetic rubber

• 1 EPDM rubber (EPDM)
• Ethylene \ acrylic \ third monomer. Excellent overall performance, and versatile.
• 2 silicone (SR or Q)
• Use the widest temperature range, -120 --- + 250 ℃, the lowest toxicity.
• 3-fluoro-rubber (FKM or FPM)
• Fire. Oil. Solvent glue all the best.
• 4 Polyurethane (PU): the best wear resistance.
• 5 Other: PS ACM ECO CPE CSM, etc ....

• toxic rubber material
• Scientific proof:
• Most of the rubber material is toxic or non-toxic. Its toxicity is also smaller than the salt. As long as good protective measures, the body will not cause much harm.
Knowledge rubber compound of formula

• recipe structure:
 
• raw rubber: also called gum, not add other ingredients.
 
• Curing agent: The rubber molecule linking and shaping of substances such as sulfur, peroxide and the like.
 
• accelerators: Accelerated curing agent decomposition and promote vulcanization molding and other substances such as TT CZ.

• agent: accelerant accelerate decomposition of materials such as rubber activation ZNO SA, etc ....
 
• reinforcing agents: increased green strength of the material, such as carbon black, white carbon and the like.
 
Recipe Examples
• NBR7001 (unit: shares)
• N3350 raw rubber 100
• Zinc oxide 5
• stearate 1
• Antioxidant RD 1
• DR Dispersant 1
• N774 carbon black 75
• White carbon black 15
• Calcium carbonate 40
• DOP 12
• Sulfur 1.5
• accelerator TT 0.5
• accelerator CZ 1.5
 
 
• SR wire casing recipe
 
• methyl vinyl silicone rubber 100
 
• 2 # fumed carbon black 30
 
• Two-February 1
 
• diphenylsilandiol 5
 
• Plasticizers: Also called softeners, reducing rubber hardness of most of oils, such as DOP, paraffin oil and so on.
• Antioxidant: reinforced rubber material to resist damage of light, heat, oxygen, ozone, ultraviolet rays, such as 4010-NA, RD, and so on.
• Other:
• such as dispersants, release agents, fragrances, foaming agents, tackifiers and the like.

The plastic material used for the curing temperature

• rubber
• NR. IR
• SBR. BR. PU
• NBR.CR.FKM
• EPDM. IIR
• SR
• curing temperature (℃)
• 40 ----- 160
• 150 ----- 170
• 160 ----- 180
• 170 ----- 185
• 160 ----- 190
Lack of material solutions

• 1. An additional exhaust ducts.
• 2. Multi-exhaust.
• 3. increase the pressure.
• 4. change the recipe, to increase fluidity of rubber.
• 5. change the formula to extend the scorch time, to prevent numbness.
• 6. increased material thickness.

Common defects and corrective measures
• lack of material:
• Cause:
• The air between a rubber mold and can not be discharged.
• 2 weigh enough.
• 3 pressure is insufficient.
• 4 rubber illiquid.
• 5 mold temperature is too high, rubber scorch.
• 6 rubber early scorch (dead material).
• 7 material is not thick enough, the flow is not sufficient.

Blooming white:
• Cause:
• 1. cure deficiencies.
• 2. with an excess of agents, more than rubber solubility.
 
• Solution:
• 1. When prolonged or take secondary sulfide sulfur.
• 2. Adjustment formula, reducing the amount of low-solubility complexing agent.

Bubbles. Hair hole
• Cause:
• 1. Insufficient vulcanization.
• 2. Insufficient pressure.
• 3. The mold or rubber compound impurities or oil.
• 4. Vulcanizing mold temperature is too high.
• 5. Curatives plus less, curing speed is too slow.

Bubbles. Remedy hair hole
• 1. Pressurization
When • 2. Lengthen sulfur
• 3. Adjustment formula to accelerate curing speed.
• 4. More exhaust.
• 5. Mold temperature is not too high.
• 6. Increase the amount of curing agent.
Heavy leather cracking.
• Cause:
• 1. Curing too fast, plastic flow is not sufficient.
• 2. Mold dirty or sticky gum stains.
• 3. Dusting agent or release agent too.
• 4. Plastic material thickness is not enough.

Heavy leather. Cracking solutions
• 1. Lower mold temperature, slow cure speed.
• 2. Keep rubber mold clean.
• 3. Less with a release agent or release agent.
• 4. Plastic material thick enough.
Product ejection fracture
• Cause:
• 1. Mold temperature is too high or too long when sulfur.
• 2. Excessive amount of curing agent.
• 3. Stripping the right way.
Product ejection fracture
• Solution:
• 1. lower mold temperature.
• 2. When shortening sulfur.
• 3. reduce the amount of curing agent.
• 4. Spray release agent.
• 5. take proper stripping methods.
Difficult to process
• Cause:
• 1. Product good tear strength, (such as high tensile plastic). This performance is difficult to process burr tear down.
 
• 2. Product strength bad, the performance is very crisp edges, the product will even tear together.
Difficult to process
• Solution:
• 1. If you can not afford a tear, you have to adjust the formula, and more filled with the agent, reduce shrinkage.
• 2. If it is torn, then
• a lower mold temperature, shorten sulfur.
• b reduce the amount of curing agent.
• c adjustment formula, increase strength plastic material