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If you are plastic manufacturers, you must have heard about polymer compounding. In this article, we will learn the concept, properties, applications and some common types of this material.

Related:

- 6 polypropylene compounds for automotive applications

- ABS engineering plastic - definition and applications

- 5 types of engineering plastic compounds for technical components

- How are engineering plastics used in the production of household appliances?

1. Polymer compounding? What is it?

Polymer compounding (also known as plastic compounding) is a compound consisting of primary plastic, coloring agents and reinforcing agents that enhance the desired properties of the finished plastic product.

What are the advantages of polymer compounding? Nowadays, plastic compound is very popular in the production of products/parts due to its "all-in-one" nature. That is, the manufacturer will not have to mix any additives into the raw materials, but only need to use the plastic compound to create the finished product. The 5 breakthroughs that polymer compounding bring to businesses include:

- Tailor-made for each finished product
- Full features in a single material
- Improve the quality of finished products
- Improve productivity
- Cost savings

Usually, each technical product will have its own corresponding plastic compound formula and is highly customizable. This is the disadvantage of this material. Because customization requires manufacturers to spend a lot of time and effort researching formulas. Therefore, tthe cost of polymer compounding will certainly be higher than other types of plastic materials. Not to mention, if you want to buy products from overseas polymer compounding companies, exchanging and testing samples will face many disadvantages due to geographical distance.

2. Properties of polymer compounding

To achieve the above characteristics, various types of engineering plastics (POM, PBT, SAN, SAN, ABS, PC, HIPS, GPPS...) will be mixed with the following additives and reinforcements: 
- Talc mineral with high purity
- Barium Sulfate Powder (BaSO4)
- Clay with nanoscale
- Ceramic beads
- Glass beads/fibers
- Conductive carbon black
- Flame retardant with or without halogen

3. Applications of polymer compounding

- Industrial products: Gears, bearings, transmission belts, rolls, plumbing connectors, hand tools.
- Electrical/Electronic Products: Computer components, OA office gears, household electrical components, camera components
- Civil products: Watches, zippers, baby car details, bathroom accessories, window rails.
- Car / motorcycle components: Exhaust valve, lock mold, fuel tank cap, carburetor components, wiper components, wiring board, gear assembly.
- Sports equipment: Bicycles, fitness equipment, beach car accessories
- Application in motorcycles, aerodynamic tools, machine components, components with high hardness and low shrinkage, industrial components with low working temperature impact, smooth glossy surface, shrinking industrial components low, high-strength, wear-resistant industrial components

Related:
- Important applications of engineering plastic compound in automotives

 

4. Common polymer compounding you should know

4.1. PP compound

a. PP glass fiber compound

This is a PP plastic compound product reinforced with glass fiber at the rate of 30-40%. Adding fiberglass to plastic materials enhances the following properties:
- Increase product stiffness
- Reduce product shrinkage
- Reinforcement of PP plastic base
- Increase product heat resistance
- Good impact resistance

 

Applications of glass fiber PP compound include: Automotive and motorcycle industry, electrical appliances industry, furniture industry...

Technical specifications of PP glass fiber compound

Feature	Method	Units	PP 20 GF	PP 30GF	PP 40GF
Melt Flow Rate (230°C/2.16kg)	D 1238	g/10 min	5	4	3
Density	D 792	g/cm³	1.033	1.104	1.191
Tensile Strength at Break (a)	D 638	MPa	50	67	75
Elongation at Break (a)	D 638	%	3 - 5	3 - 5	3 - 5
Flexural Modulus	D 790	MPa	4078.2	5077.0	6055.1
Izod Impact Strength (b)	D 256	J/m	14.156	19.094	20.304
Deflection Temperature under Load at 0.455 MPa (b)	D 648	ºC	117	130	140
Mold shrinkage	50x70x3 mmt	%	0.3 – 0.6	0.3 – 0.6	0.3 – 0.6
Flammability	UL 94		HB
Hardness RockWell		HRR		53	65

b. PP glass bead compound

Applications of glass beads PP compound include: Automotive interior industry, home appliance industry, furniture decoration industry...

Technical specifications of PP glass bead compound

c. PP Talc compound

Using talc powder in thermoplastics gives the following results:
- Increased stiffness and flexural modulus
- Increased flexural strength
- Reduced creep tendency as temperature increases
- Improved heat distortion temperature and dimensional stability
- Improved shrinkage, less warping, low coefficient of thermal expansion
- Good thermal conductivity
- Increase the surface hardness of the mold.

However, using talc in thermoplastics has the following disadvantages:
- Reduce tensile stress and elongation at break
- Reduce impact strength of notched samples, increase brittleness
- Low flow index of the mixture
- Anisotropic reinforcement and shrinkage
- Discoloration of composite materials, depending on the color of the talc used.
- Not suitable for food use (with asbestos, heavy metals)
- Pure products have high prices
- Affects heat stabilizers in some plastics.

PP compound with 20% talc powder and additives are often applied to the production of motorcycle and auto parts, products that require good formability, high heat resistance (120-130oC) for a long time. 

 

Technical specifications of PP Talc compound

Feature	Method	Units	PP 20 T	PP 30T	PP 40T
Melt Flow Rate (230°C/2.16kg)	D 1238	g/10 min	4.3	4.2	3.9
Density	D 792	g/cm³	1.032	1.130	1.196
Tensile Strength at Break (a)	D 638	MPa	25.24	29.80	30.03
Elongation at Break (a)	D 638	%	3 - 5	3 - 5	3 - 5
Flexural Modulus	D 790	MPa	1628.8	1952.7	2087.1
Izod Impact Strength (b)	D 256	J/m	17.303	15.442	15.269
Deflection Temperature under Load at 0.455 MPa (b)	D 648	ºC	110	130	140
Mold shrinkage	50x70x3 mmt	%	0.3 – 0.6	0.3 – 0.6	0.3 – 0.6
Flammability	UL 94		HB
Hardness RockWell		HRR	65	70	84

d. PP BaSO4 compound

This is a PP plastic compound reinforced with BaSO4 at the rate of 30-50%. The characteristics of the PP BaSO4 plastic compound are:
- Increase the gloss of the product
- Increase product hardness
- Increase product formability
- Increasing deformation temperature
- Reduce product shrinkage

The product is applied to the production of sanitary equipment, plastic products for the electromechanical industry such as rice cookers, water purifiers, vacuum cleaners, etc.

Technical specifications of PP BaSO4 compound

Feature	Method	Units	PP 20B	PP 30B	PP 40B
Melt Flow Rate (230°C/2.16kg)	D 1238	g/10 min	14.2	13.9	13.3
Density	D 792	g/cm³	1.037	1.150	1.283
Tensile Strength at Break (a)	D 638	MPa	25.98	20.69	24.43
Elongation at Break (a)	D 638	%	3 - 5	3 - 5	3 - 5
Flexural Modulus	D 790	MPa	1075.6	1151.1	1201.1
Izod Impact Strength (b)	D 256	J/m	15.588	18.810	16.084
Deflection Temperature under Load at 0.455 MPa (b)	D 648	ºC	88	96	97
Mold shrinkage	50x70x3 mmt	%	0.3 – 0.6	0.3 – 0.6	0.3 – 0.6
Flammability	UL 94		HB	HB	HB
Hardness RockWell		HRR	72	60	49

e. PP Carbon Black Conductive compound

This is a PP engineering plastic mixed with carbon black conductive particles. This type of polymer compounding has the following characteristics:
- PP-H with improved electrical conductivity.
- Volume resistivity ≤ 106 Ω,
- Surface resistivity ≤ 106 Ω.
- A higher stability in contrast to the standard PP

Technical specifications of PP Carnon Black Conductive compound

Feature	Method	Units	PP 20C
Melt Flow Rate (230°C/2.16kg)	D 1238	g/10 min	20
Density	D 792	g/cm³	0.98
Tensile Strength at Break (a)	D 638	MPa	18
Elongation at Break (a)	D 638	%	5-7
Flexural Modulus	D 790	MPa	1417
Izod Impact Strength (b)	D 256	J/m	11
Deflection Temperature under Load at 0.455 MPa (b)	D 648	ºC	101
Volume resistivity Surface resistivity	IEC 60093	Ω•cm  Ω	104 - 106
Flammability	UL 94		HB
Hardness RockWell		HRR	72.2

f. PP flame retardant compound

Flame retardant compound are blended from PP plastic with flame retardant additives, fire retardant levels according to UL 94 standards: V0, V1 and V2.

There are 2 types of flame retardant compounds:
- Halogen flame retardant: Chlorine, Bromo
- Non-halogen flame retardant: Mg(OH)2, Al(OH)3, Sb2O3, Phosphorous. 

You can read more about common types of halogen-free flame additives.

Flame retardant PP plastic compounds are used in electronic industry, and products requiring fire resistance.

Technical specifications of PP flame retardant compound

Feature	Method	Units	PP FRV0
Melt Flow Rate (230°C/2.16kg)	D 1238	g/10 min	6
Density	D 792	g/cm³	1.24
Tensile Strength at Break (a)	D 638	MPa	23
Flexural Modulus	D 790	MPa	1586
Izod Impact Strength (b)	D 256	J/m	43
Flammability	UL 94		V0

4.2. ABS plastic compound 

ABS compound is an Acrylonitrile Butadiene Styrene that offers high impact properties and has good thermal, dimensional stability and good scratch resistance. 

Characteristics: 
- High impact properties 
- Good thermal and dimensional stability 
- Good scratch resistance 
- Good electrical insulative properties 
- Maximum operating temperature +180 °F Applications: Parts with a high impact strength, spacers, rollers, prototypes, electronic industry.

a. ABS flame retardant compound

The flame retardant compound product is blended from ABS plastic with flame retardant additives, fire retardant levels according to UL 94 standards: V0, V1 and V2.

There are 2 types of flame retardant compounds:
- Halogen flame retardant: Chlorine, Bromo
- Non-halogen flame retardant: Mg(OH)2, Al(OH)3, Sb2O3, Phosphorous. 

 

Technical specifications of ABS flame retardant compound

Feature	Method	Units	ECP ABS 1001V2	ECP ABS1001V0
Melt Flow Rate (200°C/5 kg)	D 1238	g/10 min	5	25
Density	D 792	g/cm³	1.2	1.22
Tensile Strength at Break (a)	D 638	MPa	40	38
Elongation at Break (a)	D 638	%	3 – 5%	3 – 5%
Flexural Modulus	D 790	MPa	2340	2000
Izod Impact Strength (b)	D 256	J/m	210	130
Deflection Temperature under Load at 1.8 MPa (b)	D 648	ºC	81	75
Flammability	UL 94		V2	V0

b. ABS glass fiber compound

Compound ABS GF is a product of ABS plastic compound with glass fiber to strengthen ABS base plastic, helping to increase hardness and HDT deformation temperature, VICAT softening temperature.

The main application of this compound product is in the following fields:
- Electronic equipment, printers and printer cartridges.
- Equipment requires high rigidity and low cost.
- Some details in the automotive industry, motorcycles….

Technical specifications of ABS glass fiber compound

Feature	Method	Units	ABS 20 GF	ABS 30 GF
Melt Flow Rate (200°C/5kg)	D 1238	g/10 min	1.65	1.158
Density	D 792	g/cm³	1.63	1.204
Tensile Strength at Break (a)	D 638	MPa	40.81	33.81
Elongation at Break (a)	D 638	%	2 - 3	2 - 3
Flexural Modulus	D 790	MPa	3376.2	4603.12
Izod Impact Strength (b)	D 256	J/m	22.550	21.470
Deflection Temperature under Load at 0.455 MPa (b)	D 648	ºC	97.4	98
Flammability	UL 94		HB	HB
Hardness RockWell		HRR	106	105

4.3. PC glass fiber compound

PC plastic compounds with fiberglass offer the following characteristics:
- Increased surface hardness
- Good impact resistance
- Good thermal properties

Applications of the product include 
- Computer components, OA office gears, household electrical components, camera components.
- Low-shrink industrial components, high-strength, wear-resistant industrial components.

Technical specifications of PC glass fiber compound

Feature	Method	Units	PC 20GF	PC 30GF
Melt Flow Rate (300°C/1.2kg)	D 1238	g/10 min	91.98	136.56
Density	D 792	g/cm³	1.070	1.157
Tensile Strength at Break (a)	D 638	MPa	23.78	46.16
Elongation at Break (a)	D 638	%	3 - 5	3 - 5
Flexural Modulus	D 790	MPa	4442.8	6343.8
Izod Impact Strength (b)	D 256	J/m	25.233	35.368
Deflection Temperature under Load at 1.8 MPa (b)	D 648	ºC	124.2	124.7
Flammability	UL 94		HB	HB
Hardness RockWell		HRR	116	105