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Introduction to Main Raw Materials and Implementation Standards:

1 Natural rubber NR:

Commonly used natural rubbers for conveyor belts include: national standards. 1# National standard 2# Import No. 3.

Performance features: NR It has high elasticity at room temperature but gradually softens when heated. 130 — 140 ℃ begins to flow, 150 — 160 Above ℃, it becomes a highly viscous viscous fluid. 200 It begins to decompose at ℃, 270 ℃ then decomposes rapidly, while in -70 — -72 At ℃, it becomes a brittle substance but returns to its normal state after baking the rubber.

Advantages: NR It has high self-reinforcing properties, and the tensile strength of the vulcanized pure rubber can reach... 17 — 19Mpa , can reach under carbon black reinforcement 25 — 35Mpa。

NR It exhibits excellent resistance to flexural fatigue, low operating heat generation, high tear strength, easy processing, and high self-adhesion.

Disadvantages:

1 )   Not resistant to aging. 2 ) Prone to sulfur reversion. 3 ) Poor heat resistance. 4 ) Poor oil resistance and resistance to non-polar solvents. 5 Flammable.

Implementation standard: GB8081-87

2 Styrene-butadiene rubber SBR. (Light-colored or brown elastomer)

We use it. SBR Mainly 1502

SBR1502 Physical and mechanical properties and processing characteristics.

( 1 ) The vulcanization rate is relatively slow, offering high processing safety and being less prone to scorching or over-vulcanization, with excellent vulcanization flatness.

( 2 ) It has good wear resistance, breathability, and heat resistance, but poor elasticity, cold resistance, and tear resistance. It generates significant heat during processing and exhibits poor resistance to flexural cracking (meaning that cracks tend to grow rapidly after flexural cracking occurs).

( 3 ) It has better chemical resistance, water resistance, and electrical insulation properties than natural rubber;

( 4 ) SBR Without self-reinforcement, the tensile strength of a pure rubber vulcanizate is only... 2-5mp And after carbon black reinforcement, the tensile strength can reach... 25-28mpa

( 5 ) Poor processing performance—pure rubber is difficult to adhere to the rollers (during open-mill mixing); semi-finished products exhibit high shrinkage or expansion rates and have poor adhesion during molding and bonding.

Execution Standard Number: GB12824-1991 ( 1502 ) Compounding agents

3 Sulfur powder S (Light yellow or yellow powder)

Performance features:   Melting point 114-118 °C, 100 Full view.

The most important technical requirement for sulfur is its purity; when the impurity content is high, it should be appropriately increased. S The dosage. Too fine. S It tends to agglomerate during mixing and is difficult to disperse. S The acidity should not be too high; otherwise, vulcanization will be delayed and bubbles will form.

Soft rubber, generally 2~3.5 Piece. Hard rubber 30~50 portion.

Application in conveyor belts: NR General application 2.5 portion

SBR General application 1.5–2.5 portion

Implementation standard: GB/T2449-1992

4 Accelerator M (Light yellow powder, extremely bitter taste)

Performance characteristics: Low critical temperature ( 125 ℃), it exhibits a fast vulcanization rate and a moderate scorch time. When used with alkaline furnace black, there is a risk of scorching; it serves as a plasticizer for natural rubber. It disperses easily during mixing.

Application in conveyor belts:   Act as the primary accelerator 1~1.5 portion

Act as a second accelerator 0.2~0.5 portion

Implementation standard: HG11407-1989

5 Accelerator DM (White or pale yellow powder with a slightly bitter taste)

Performance feature: Critical temperature 130 ℃, the sulfur rate is relatively M Slightly slower, with a longer scorching time, good mold-filling performance, and easy dispersion.

Application in conveyor belts: General 0.5~2 portion.

6. M and DM It exhibits good overall performance in compounded vulcanized rubber, featuring high tensile strength and elongation at break, moderate stress at a specified strain and hardness, excellent abrasion resistance and aging resistance, as well as low compression set.

Implementation standard: GB/T11408-1989

7 Accelerator TMTD (White powder that emits a pungent odor when airborne)

Performance feature: Low critical temperature 100 °C,

When used as an accelerator, it is prone to scorching, exhibits rapid sulfurization, has poor vulcanization flatness, and excessive use can easily lead to overvulcanization and premature curing. (The vulcanization temperature should be...) 125~135 between ℃)

When used as a vulcanizing agent, it exhibits low scorch tendency, excellent vulcanization flatness, and the resulting vulcanizate boasts outstanding resistance to thermal aging, minimal heat generation, and low compression set. However, the vulcanizate has high tensile strength, relatively low stress at a given elongation, poor resistance to flexural fatigue, and is prone to blooming.

Application in conveyor belts: In NR When used as a secondary accelerator ( 0.05~0.1 )

As a secondary accelerator in synthetic rubber, ( 0.2~0.5 ).

Implementation standard: HG/T2334-1992

8 Zinc oxide Zinc oxide (Amphoteric oxide, a white, fine powder that is non-toxic and odorless)

Performance feature: Indirect method Zinc oxide High purity, fine particles, high activity.

Direct method Zinc oxide Slightly lower purity, coarser particles, higher content of heavy metal impurities, and poor activity.

In addition to acting as an activator, zinc oxide also enhances reinforcement, imparts color, and improves the thermal conductivity of the rubber compound.

Application in conveyor belts: Typical dosage 2.5-5 portion

Live in the tropical zone 10 portion.

Implementation standard: GB3494-1983

9 Stearic acid stA. ( White or slightly yellowish granular or lumpy substance with a slight fatty odor, odorless. Poison. )

Performance characteristics: Industrial-grade purity is only 80-90% The remaining components are oleic acid or palmitic acid. stA In addition to acting as an activator, it also has a softening and plasticizing effect, which helps disperse carbon black. Using too much can cause the substance to exude onto the surface of the product and delay the vulcanization of the rubber compound.

Application in conveyor belts: 0.5~2 portion

Implementation standard: GB9103-1988

10 Carbon black N330 HAF

Performance characteristics: High-reinforcing carbon black. Abrasion resistance is higher than... N220 Slightly inferior, widely applicable to NR The reinforcement effect is relatively good.

In conveyor belts, it is mainly used for cover rubber and adhesive application.

Implementation standard: GB/T3778-1994

11. Carbon black N220 ISAF

Performance characteristics: High-reinforcing furnace black, with abrasion resistance between... SAF and HAF Among them, it can impart excellent tensile strength to the rubber compound. It is particularly effective in reinforcing styrene-butadiene rubber.

The primary reinforcing material used in conveyor belts: mainly for general-purpose applications and for heat-resistant belt cover rubber.

Implementation standard: GB/T3778-1994

12 Antioxidant RD___ It inhibits oxidation, thermal aging, and weathering, but has relatively poor resistance to flexural cracking.

13 paraffin ___ It primarily prevents ozone cracking of the product. It also has a significant effect on adhesion.

14 Pine tar ___ It helps enhance the dispersion of compounding agents, increases viscosity, improves the cold resistance of the product, and delays vulcanization when used in excess.

15 · Coumarone __  Softening and plasticization help disperse carbon black, enhance adhesion, and provide a certain degree of reinforcement; however, they reduce flexural resilience.