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Rubber Basics Introduction
Release time:2015/4/12 15:48:20
o Popular definitions:
o 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.
 
o Rubber origins:
o by native tropical American tree crying tears dried emulsion solidified.
 
o Development:
o curing method of the invention.

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

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

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

o toxic rubber material
o Scientific proof:
o 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

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

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

The plastic material used for the curing temperature

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

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

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

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

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

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

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

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