Polyethylene masterbatch is widely used in the production of various plastic products, such as plastic bags, plastic films, plastic pipes, etc. By adding different additives and fillers, polyethylene products with different properties and uses can be produced. The production of polyethylene masterbatch is a complex and delicate process that requires strict control over raw material quality, equipment selection, process parameters, and safety production. By continuously optimizing production processes and formulas, the quality and performance of masterbatch can be improved to meet market demand.

Feature

The core characteristics of PE masterbatch revolve around “efficient empowerment of PE product production”, which not only solves the pain point of directly adding additives, but also has core advantages such as adaptability, stability, and convenience. Specifically, it can be divided into the following 8 key features:

1. Strong dispersion uniformity (core advantage)

The functional components (color powder, filler, and additives) are pre dispersed in the masterbatch and form a stable system with the PE carrier resin. When used, they can be quickly and uniformly integrated into pure PE raw materials, avoiding problems such as “color spots, filler aggregation, and uneven functionality”, greatly improving the color consistency and performance stability of the product (such as no deviation in coloring of the masterbatch, and uniform anti-static effect of the anti-static masterbatch).

2. Convenient and efficient use

The granular form is easy to measure and mix, without the need for additional grinding or dispersion treatment (compared to directly adding color powder/fine powder additives), reducing the operating threshold;

After mixing with PE raw materials, it can directly enter extrusion, injection molding and other equipment without adjusting the production process, shortening the production process and improving production efficiency.

3. Excellent cost controllability

High concentration concentrated design (functional ingredients account for 20% -60%), only 1% -30% of the total product mass needs to be added during use (such as coloring 3% -5%, filling 10% -30%), reducing waste of functional ingredients;

Avoid cleaning costs caused by scattered additives contaminating equipment and adhering to inner walls, while reducing losses from excessive additives, resulting in lower overall long-term production costs.

4. Stable and reliable performance

The formula is accurate and controllable, the functional component content and dispersion effect of the same batch of masterbatch are consistent, ensuring that the performance of PE products produced in batch is not fluctuated (such as the antioxidant content of anti-aging masterbatch is stable, and the service life of products is uniform);

The functional components are wrapped in a carrier to reduce contact with air and moisture, lower the risk of oxidation and failure, and slow down performance degradation during storage and use.

5. Wide compatibility and adaptability

The carrier resin is fully compatible with PE raw materials (corresponding matching of LDPE/HDPE/LLDPE carrier), without affecting the original properties such as formability and toughness of PE products;

It can adapt to various PE processing techniques such as extrusion, injection molding, blow molding, and film forming, without the need for targeted adjustment of masterbatch types, and has strong versatility.

6. Flexible customization of functions

According to the needs of PE products, functional ingredients and proportions can be accurately allocated to achieve “one master batch with one function” or “multi-function composite” (as with coloring+antistatic+anti-aging composite master batch), covering the whole scene needs of coloring, filling, modification, function strengthening, etc., and suitable for packaging, building materials, agriculture, household appliances and other fields.

7. Physically friendly

The granular structure is dust-free and odorless, and will not pollute the workshop environment during use, nor will it wear down the extruder screw and die head (compared to fine powder additives);

The density is close to that of PE raw materials, making it difficult to separate layers during mixing, ensuring stability in the subsequent molding process;

Convenient storage and transportation, no need for special protection, can be stored for a long time at room temperature, and is not easy to clump or deteriorate.

8. Better environmental friendliness

The functional ingredients are concentrated and packaged to reduce the volatilization and scattering of additives during the production process, thereby reducing environmental pollution;

Partial filling masterbatch can use environmentally friendly fillers such as calcium carbonate and wood powder, or biodegradable PE carriers, which are in line with the trend of green production;

Reduce the product waste rate caused by excessive use of additives, improve raw material utilization, and indirectly reduce environmental pressure.

Types

The core types of PE masterbatch are divided according to “functional use”, and different types correspond to specific requirements of PE products (coloring, cost reduction, functional strengthening, performance modification, etc.). Some can achieve “multifunctional composite”. The following are the mainstream classifications and key details in the industry:

I. Core Basic Types (Divided by Core Functions)

1. Color masterbatch (most commonly used, accounting for over 60% of the PE masterbatch market)

Core function: Accurately color PE products to ensure uniform and consistent color

Key components: high concentration color powder (carbon black, titanium dioxide, organic/inorganic pigments)+PE carrier+dispersant

Common segmentation:

Black masterbatch (with a carbon black content of 20% -50%, used for pipes, films, and injection molded parts);

White masterbatch (with a titanium dioxide content of 40% -60%, used for packaging films and household appliance shells);

Colored masterbatch (organic pigments such as red/blue/yellow, used for toys, food packaging, and decorative items).

Typical applications: PE shopping bags, pipes, blow molded bottles, injection baskets, film packaging.

2. Fill masterbatch (cost reduction+basic modification)

Core function: Reduce the raw material cost of PE products while improving rigidity, heat resistance (or lightweighting)

Key components: high proportion filler (50% -80%)+PE carrier+dispersant/coupling agent

Common segmentation:

Calcium carbonate filled masterbatch (the most economical, used for garbage bags, packing belts, and inner walls of pipes);

Talc powder filled masterbatch (to enhance rigidity, used for household appliance bases and injection molded shells);

Wood powder/bamboo powder filling masterbatch (environmentally friendly and biodegradable, used for outdoor pallet boards and decorative parts);

Mica powder filled masterbatch (to enhance heat resistance, used for high-temperature environment accessories).

Typical applications: PE garbage bags, packing tapes, low-pressure pipes, injection molded backboards.

3. Functional masterbatch (targeted reinforcement of specific properties)

Core feature: Single function focus, solving the “weakness problem” of PE products.

Type	Core functionality	Key components	Typical application scenarios
Anti-aging masterbatch	Extend the lifespan of outdoor PE products (UV/antioxidant)	Antioxidant (1010/168)+light stabilizer (UV531)	PE film, outdoor pipe, greenhouse film
Antistatic masterbatch	Eliminate static electricity and prevent dust adsorption	Cationic/non-ionic anti-static agent	Electronic component packaging film, PE tray, food packaging film
Flame Retardant Masterbatch	Endow with flame retardant properties (compliant with flame retardant rating)	Bromine based/halogen-free flame retardant (magnesium hydroxide/aluminum)	Building PE pipes, electrical enclosures, flame-retardant packaging films
Open-mouth masterbatch	Prevent PE film adhesion and facilitate opening	Silicon dioxide, talc powder, stearic acid amide	PE shopping bags, packaging films, greenhouse films
Smooth masterbatch	Improve the surface smoothness of the product and reduce friction	Oleic acid amide, erucic acid amide	PE film, surface of injection molded parts, inner wall of pipes
Antimicrobial Masterbatch	Inhibit bacterial growth (in food/medical settings)	Silver ion, zinc oxide antibacterial agent	Food contact PE containers, medical packaging, baby products
Anti fog masterbatch	Avoid fogging on the inner wall of PE film (transparent)	Glycerol fatty acid esters, polyethylene glycol	Fresh packaging film, greenhouse film, food preservation film

4. Modified masterbatch (improving the core performance of PE substrate)

Core features: Optimize the mechanical properties of PE (strength, toughness, wear resistance, etc.) and expand its engineering applications.

Type	Core functionality	Key components	Typical application scenarios
toughening masterbatch	Improve low-temperature impact resistance (anti brittle fracture)	POE、EVA、 Elastic toughening agent	PE pipes, low-temperature environment accessories, and films for winter use
Enhanced masterbatch	Enhance tensile strength and rigidity	Fiberglass, carbon fiber, basalt fiber	PE engineering accessories, mechanical shells, high-strength pipes
Wear resistant masterbatch	Reduce surface friction coefficient and wear resistance	Graphite, PTFE (polytetrafluoroethylene) MOS2	PE gear, slider, pipe interface, wear-resistant accessories
Heat-resistant masterbatch	Raise the heat-resistant temperature of PE (+10-30 ℃)	Nucleating agent, high-temperature resistant filler (talc powder/fiberglass)	Hot water pipes, packaging for high-temperature environments, heat-resistant components for household appliances
Compatible masterbatch	Improve the compatibility between PE and other materials	PP-g-MAH, PE-g-MAH compatibilizer	PE/PA blend products, PE and filler composite system

II. Special type (scenarized/composite function)

1. Composite functional masterbatch (multifunctional integrated)

Core features: integrate multiple functions (such as coloring+antistatic, anti-aging+opening, filling+toughening), reduce the types of masterbatch addition, and simplify the production process.

Example: PE film uses “coloring+antistatic+anti-aging” composite master batch, and pipes use “filling+anti-aging+wear-resistant” composite master batch.

2. Biodegradable PE masterbatch

Core function: endowing PE products with biodegradability (in line with environmental policies), using biodegradable PE as the carrier (such as PLA/PE blend), and adding degradation promoters.

Application: Disposable PE shopping bags, agricultural film, food packaging (must meet biodegradable standards).

3. Customized special masterbatch

Develop for special scenario requirements, such as:

Thermal conductive masterbatch (including aluminum nitride and aluminum oxide, used for electronic heat dissipation accessories);

Conductive masterbatch (containing carbon black and conductive fibers, used for anti-static packaging and conductive pipes);

Weather resistant and UV resistant masterbatch (high content light stabilizer, used for PE products for long-term outdoor use).

III. Classification Core Logic Summary

Select according to “priority of demand”: Color masterbatch for coloring → Fill masterbatch for cost reduction → Functional masterbatch for addressing performance shortcomings → Modified masterbatch for improving mechanical properties;

Adapt according to the “processing technology”: commonly used opening/smooth/antifogging masterbatch for film molding, commonly used toughening/strengthening/wear-resisting masterbatch for injection molded parts, and anti-aging masterbatch must be selected for outdoor products;

Match by “PE type”: LDPE/HDPE/LLDPE carrier masterbatch needs to correspond to the PE raw material used in the product to ensure compatibility (such as HDPE carrier masterbatch for HDPE pipes).

Formula ratio

The PE masterbatch formula follows a ternary structure of “carrier+functional components+additives”, and the proportions of each component vary significantly depending on the type of masterbatch.

I. Basic Composition Proportion Framework

Type	Typical proportion range	Functional positioning	Selection basis
Carrier resin	10%-60%	Carrying functional components and providing processing fluidity	Match with the PE type of the product (LDPE/HDPE/LLDPE)
Functional powder	20%-80%	Implement core functions (coloring/filling/flame retardant, etc.)	Select based on the target function (pigment/filler/functional agent)
Dispersant	2%-20%	Ensure uniform dispersion of functional powders	The dosage of PE wax, stearic acid salt, etc. is related to the specific surface area of the powder
Processing aid	1%-5%	Improve processing performance and enhance stability	Antioxidants, lubricants, coupling agents, etc

II. Detailed explanation of the proportion of mainstream PE masterbatch formula

1. Color masterbatch series

White masterbatch (universal type)

Titanium dioxide: 40% -60% (high whiteness of rutile type, low cost of anatase type)

Carrier resin: 15% -25% (LLDPE/LDPE blend to enhance dispersibility)

Dispersant: 10% -15% (PE wax+stearic acid composite system)

Lubricant: 2% -5% (Zinc/Calcium stearate, improves flowability)

Other: Antioxidant 0.5% -1% (1010/168 complex)

Example formula: TiO ₂ 62.7%, LDPE 18.4%, LLDPE 4.6%, PE wax 12%, oleic acid amide 2.3%

black masterbatch

Carbon black: 20% -50% (high pigment carbon black 20% -30%, ordinary carbon black 30% -50%)

Carrier resin: 20% -40% (mainly HDPE, providing heat resistance)

Dispersant: 8% -15% (PE wax+sodium stearate composite)

Other: Antioxidants 0.5% -1%, UV protection additives 1% -3% (for outdoor use)

Example formula: 40% carbon black, 50% HDPE resin, 8% dispersant, 2% antioxidant

2. Filling masterbatch series

Calcium carbonate filled masterbatch

Calcium carbonate: 50% -85% (1250-2000 mesh, the smaller the particle size, the better the dispersibility)

Carrier resin: 10% -30% (LLDPE/LDPE as the main component, enhancing compatibility)

Coupling agent: 1% -3% (titanium/aluminum ester, to enhance the adhesion between filler and resin)

Dispersant: 3% -10% (PE wax, reducing melt viscosity)

Lubricant: 1% -3% (stearic acid, improves extrusion smoothness)

Example formula: 70% calcium carbonate LDPE 20%、 Coupling agent 1%, dispersant 8%, lubricant 1%

Talc powder filled masterbatch

Talc powder: 40% -60% (above 3000 mesh, improves product rigidity)

Carrier resin: 15% -30% (mainly HDPE, enhancing heat resistance)

Coupling agent: 1% -2% (silane based, enhances interfacial bonding)

Dispersant: 3% -8% (PE wax+white oil composite)

Other: Antioxidant 0.5% -1%

3. Functional masterbatch series

Anti-aging masterbatch

Antioxidant: 0.5% -3% (main antioxidant 1010 0.3% -1.5%+auxiliary antioxidant 168 0.2% -1%)

Light stabilizer: 1% -5% (UV-531/UV-327, etc., outdoor products 3% -5%)

Carrier resin: 40% -60% (LDPE/LLDPE, ensuring compatibility)

Dispersant: 3% -8% (PE wax+zinc stearate)

Other: Fillers (such as calcium carbonate) 10% -20% (to reduce costs and improve stability)

Example formula: 50% PE resin, 1.5% antioxidant, 3% light stabilizer, 5% dispersant, 40.5% filler

Flame retardant masterbatch (halogen-free type)

Magnesium hydroxide/aluminum: 40% -60% (providing flame retardant core)

Carrier resin: 20% -40% (HDPE/LDPE blend)

Flame retardant synergist: 5% -10% (zinc borate/melamine)

Dispersant: 3% -8% (PE wax)

Lubricant: 1% -3% (calcium stearate)

Other: Antioxidant 0.5% -1%

Example formula: Magnesium hydroxide 50%, PE resin 30%, synergist 8%, dispersant 6%, lubricant 4%, antioxidant 2%

Open-mouth masterbatch

Opening agent: 10% -20% (silica/talc/diatomaceous earth, to prevent film adhesion)

Carrier resin: 40% -50% (LLDPE as the main component, providing flexibility)

Dispersant: 8% -15% (PE wax+stearic acid composite)

Surface treatment agent: 5% -10% (stearic acid amide)

Processing aids: 1% -3%

Example formula: LLDPE 45.5%, dicalcium phosphate 40%, dispersant 10%, surface treatment agent 7%, processing aid 0.5%

4. Modified masterbatch series

toughening masterbatch

Elasticity: 30% -50% (POE/EVA/SBS, improves impact toughness)

Carrier resin: 30% -50% (HDPE/LLDPE, ensuring compatibility)

Compatibility agent: 3% -10% (PE-g-MAH/PP-g-MAH, improves interfacial bonding)

Dispersant: 2% -5% (PE wax)

Other: Antioxidant 0.5% -1%

Example formula: HDPE resin 80-92%, compatibilizer 1.2-2.8%, dispersant 0.2-0.45%, ultrafine phosphogypsum powder 7.75-17.5%

III. Design principles of PE masterbatch formula

1. Selection and proportion of carrier resin

Matching principle: The carrier PE type must be consistent with the product PE type (LDPE products choose LDPE carrier, HDPE products choose HDPE carrier)

Content basis:

High concentration functional masterbatch (such as colorants): carrier 20% -40%

Filling masterbatch: carrier 10% -30% (the higher the filler content, the lower the carrier proportion)

Functional masterbatch: carrier 40% -60% (ensuring uniform dispersion of functional agents)

2. Proportion control of functional powder

Coloring masterbatch: pigment concentration of 20% -60% (color 10% -30%, black and white 20% -60%), too high concentration is prone to uneven dispersion

Filler masterbatch: filler 50% -80% (selected based on cost and performance balance)

Functional masterbatch: Functional agent 5% -30% (too high affects processing performance, too low has little effect)

3. Key points of additive ratio

Dispersant: usually 10% -20% of functional powder, ensuring sufficient encapsulation and dispersion

Coupling agent: 1% -3% of the filler to enhance the bonding between the filler and resin interface

Antioxidant: 0.5% -2%, extends storage and service life

Lubricant: 1% -5%, improves processing fluidity and avoids melt fracture

IV. Recommended proportion of PE masterbatch added to products

Type	Recommended amount to add	Applicable product types	Remarks
Color masterbatch	2%-5%	Thin films, injection molded parts, and pipes	Dark color 2% -3%, light color 3% -8%
Masterbatch	8%-30%	Garbage bags, pipes, injection molded backboards	Blow film 8% -10%, injection molding 10% -30%
Anti-aging masterbatch	1%-3%	Outdoor film, pipe, agricultural film	Long term outdoor use 3%, generally 1% -2%
Flame Retardant Masterbatch	10%-30%	Building pipes and electrical enclosures	Non halogenated type requires 15% -30%, brominated type requires 5% -12%
Opening/Smooth Masterbatch	0.3%-2%	Packaging film, greenhouse film	Opening 0.5% -2%, smooth 0.3% -1%

V. Core logic of formula proportion design

Functional priority principle: Determine the main components of functional powder and their minimum effective concentration based on the target function

For example, the white masterbatch TiO ₂ content must be ≥ 40% to ensure coverage

Carrier matching strategy:

Low density products (such as films): Priority should be given to LDPE/LLDPE carriers (accounting for 40% -60%)

High strength products (such as pipes): HDPE carrier is preferred (accounting for 30% -50%)

Special performance requirements: can use blended carriers (such as LDPE+HDPE, LLDPE+EVA, etc.)

Decentralized security mechanism:

The higher the content of functional powder, the higher the proportion of dispersant should be correspondingly increased (up to 20% of the powder)

Ultra fine powder (≥ 2000 mesh) requires an increase in the amount of coupling agent and dispersant (+1% -3%)

Performance balance considerations:

Filling masterbatch: For every 10% increase in filler, the carrier needs to increase by 2% -5% to maintain processing performance

Functional masterbatch: For every 5% increase in functional agent, it is necessary to adjust the dispersant+1% -2% and lubricant+0.5% -1%

The proportion design of PE masterbatch formula is a comprehensive balancing art of “functional requirements+processing performance+cost control”. Mastering the basic ratio range of various types of masterbatch (carrier 10% -60%, functional powder 20% -80%, dispersant 2% -20%, auxiliary agent 1% -5%), and fine-tuning according to specific application scenarios, can design PE masterbatch products with stable performance.

The formula adjustment should follow the principle of “small amount multiple times”, with each change not exceeding 5%, and undergo sufficient testing and verification to ensure that the dispersibility, stability, and final product performance meet the standards.

Production process

Raw material preparation

Basic resin: Polyethylene resin is generally selected, such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), or high-density polyethylene (HDPE), etc. The appropriate variety and grade are selected according to the product performance requirements.

Additives: Various additives are added according to the functional requirements of the masterbatch, such as pigments or dyes that need to be added to the color masterbatch; Filling masterbatch requires the addition of fillers such as calcium carbonate and talc powder; Functional masterbatch is added with antioxidants, light stabilizers, flame retardants, etc.

Mixing of ingredients

Measurement: Accurately measure the amount of various raw materials and additives according to the formula requirements. Accurate measuring equipment such as electronic scales are usually used to ensure the accuracy of ingredients.

Pre mixing: Pour the measured raw materials and additives into a high-speed mixer for pre mixing. By high-speed stirring, various components are initially uniformly dispersed. The general mixing time is 5-15 minutes, depending on the characteristics of the material and the mixing effect.

Extrusion granulation

Melt extrusion: Add pre mixed materials into a twin-screw extruder. The extruder gradually heats the material inside the barrel to the melting temperature of polyethylene through heating and rotation of the screw, usually between 160-230 ℃. In the molten state, the material is subjected to the shearing and conveying effects of the screw, further mixing evenly.

Filtering: In order to remove impurities and undispersed particles from the material, filtering devices such as filters or melt filters are usually installed during the extrusion process. The filtration accuracy depends on the product requirements and is generally between 20-100 mesh.

Granulation: The filtered molten material is extruded from the die of the extruder to form continuous strips or filaments. Then it is cut into granules of a certain length by a granulator. Common granulation methods include air-cooled granulation, water-cooled granulation, and underwater granulation. Air cooled pellet cutting is suitable for occasions with high requirements for particle appearance; Water cooling has a high cutting efficiency, but there may be residual moisture on the surface of the particles; Underwater particle cutting has the advantages of regular particle shape and uniform size, but the equipment cost is relatively high.

Packaging and storage

Cooling screening: The polyethylene masterbatch particles after granulation need to be cooled to around room temperature. Then, the particles are sieved through equipment such as vibrating screens to remove particles that are too large or too small, ensuring the uniformity of the product’s particle size.

Packaging: The screened masterbatch particles are packaged according to a certain weight specification, usually using plastic woven bags or paper bags to prevent the product from getting damp or contaminated. The packaged products are stored in a dry and ventilated warehouse, waiting for factory sales.

In the production process, it is necessary to strictly control the process parameters of each link, such as temperature, pressure, screw speed, feeding speed, etc., to ensure the stability and consistency of product quality. At the same time, it is necessary to strengthen the quality inspection of raw materials and products, including the inspection of appearance, particle size, melt flow rate, density, additive content and other indicators, in order to timely discover and solve problems.

Production equipment requirements

The production equipment for polyethylene masterbatch needs to meet the requirements of high-precision measurement, uniform mixing, sufficient plasticization, precise filtration, and stable granulation. The following are specific instructions:

1. Ingredient equipment

High precision electronic scale: It is required to accurately measure various raw materials and additives, with an accuracy usually reaching ± 0.1% or higher, to ensure the accuracy of the formula.

High speed mixer: It has good mixing effect and can evenly mix materials in a short time. The speed of the mixer can be adjusted, generally between 500-2000 revolutions per minute, and it has heating and cooling functions to meet the mixing needs of different materials.

2. Extrusion equipment

Twin screw extruder: The aspect ratio is generally between 25-40 to ensure sufficient residence time and plasticization and mixing effect of the material in the barrel. The structural design of the screw should be reasonable, with strong conveying and shear mixing capabilities, and able to adapt to materials of different viscosities. The heating system of the extruder should be precise and controllable, with temperature control accuracy within ± 2 ℃, to ensure that the material is melted and extruded at the appropriate temperature.

Single screw extruder: For the production of polyethylene masterbatch with low shear requirements and high output, single screw extruders are also used. The diameter of its screw is usually between 45-150 millimeters, and the aspect ratio is between 20-30. The advantages of single screw extruder are simple structure and low cost, but the mixing effect is slightly worse than that of twin-screw extruder. Generally, optimization is needed in the screw structure and head design to improve the mixing uniformity of materials.

3. Filtering equipment

Melt filter: installed near the head of the extruder, used to filter impurities and undissolved particles in the molten material. The filtration accuracy can be selected between 20-100 mesh according to product requirements, usually using an automatic backwash filter that can clean and replace the filter screen without stopping, ensuring the continuity of production.

4. Granulation equipment

Air cooled granulator: suitable for producing polyethylene masterbatch with high requirements for particle appearance. The material of the cutting tool should be wear-resistant, and the cutting speed can be adjusted, usually 100-500 revolutions per minute, to ensure that the shape of the particles is regular and the size is uniform. The air cooling system should be able to effectively cool the particles to room temperature and avoid particle adhesion.

Water cooled pellet cutter: It has high production efficiency, and the pellets are cooled in water with fast cooling speed. But dehydration equipment such as centrifugal dehydrators or vibrating fluidized bed dryers are required to remove moisture from the surface of particles.

Underwater granulator: It is a relatively advanced granulation equipment that cuts and cools particles underwater, with the advantages of regular particle shape, high dimensional accuracy, and no dust. But the equipment cost is relatively high, and there are also strict requirements for operation and maintenance.

5. Packaging equipment

Automatic packaging machine: capable of automatically measuring and packaging according to the set weight, with a packaging speed of generally 5-10 bags/minute and a packaging accuracy of ± 0.5%. The packaging machine can be equipped with different packaging forms, such as three side sealing, four side sealing, etc., to meet the needs of different customers.

Stacking machine: For large-scale production enterprises, palletizing machines can be used to automatically stack packaged products, improving production efficiency and the standardization of warehouse management. The stacking speed and carrying capacity of the palletizer should be selected according to the production scale and product packaging weight.

6. Auxiliary equipment

Feeding system: including automatic feeding machines, hoppers, etc., which can automatically transport raw materials and additives to batching equipment and extruders, achieving automated production and reducing manual operation errors. The conveying capacity of the feeding system should match the output of the production equipment.

Cooling system: provides cooling circulating water for extruders, granulators and other equipment to ensure that the equipment operates at normal temperature. The cooling capacity of the cooling system should be calculated and selected based on the heat generation of the equipment, usually using a chiller or cooling tower as the cooling source.

Electrical control system: Centralized control and monitoring of the entire production equipment, realizing the setting, adjustment, and display of process parameters, as well as the functions of equipment start stop, fault alarm, etc. The electrical control system requires high stability and reliability, and can adapt to industrial production environments.

Problems in production

The core process of PE masterbatch production is “raw material pretreatment → mixing → melt extrusion → granulation → cooling and drying → screening and packaging”. Each link is prone to problems due to differences in raw material characteristics, process parameters, and equipment status. The following is a classification and sorting of production processes, combined with causes and practical solutions, covering the three core issues of appearance, performance, and processing stability.

I. Raw materials and mixing process: hidden dangers at the source (directly affecting subsequent molding and performance)

1. Functional powder agglomeration (color powder/filler agglomeration)

Performance: Visible black/white hard lumps and colored spots appear in the masterbatch, and subsequent products have uneven coloring/poor filling dispersion;

Cause: ① Moisture absorption of the powder (moisture content>0.1%) leads to hydrogen bonding and agglomeration between particles; ② Powder mesh size too high (>3000 mesh) without surface treatment; ③ Insufficient dosage of dispersant (less than 10% of the powder mass); ④ Not pre dispersed during mixing;

Solution: ① Pre drying the powder (drying at 100-120 ℃ for 2-4 hours, reducing the moisture content to below 0.05%); ② Add 1% -3% coupling agent (titanate/silane) to the powder for surface modification; ③ The dosage of dispersant is increased to 15% -20% of the powder (ultrafine powder can be increased to 25%); ④ First, pre mix the powder with dispersants and lubricants for 10-15 minutes, and then add the carrier resin.

2. Poor compatibility of raw materials

Performance: Melt fracture during extrusion, brittle cracking of masterbatch, or delamination during subsequent mixing with PE products;

Cause: ① Mismatch between carrier resin and functional components (such as HDPE carrier combined with LDPE special dispersant); ② Conflicts between additives (such as reactions between certain antistatic agents and flame retardants); ③ The filler does not contain a coupling agent and has weak interface bonding with PE resin;

Solution: ① The carrier resin should match the PE type of the target product (corresponding to LDPE/HDPE/LLDPE); ② Small batch testing of additive compatibility (such as mixing anti-static agents and flame retardants in proportion, observing for clumping/discoloration); ③ Coupling agents (titanium oxide for calcium carbonate and silane for talc powder) must be added to fill the masterbatch to enhance the interfacial bonding strength.

3. Uneven mixing

Performance: Color/performance fluctuations between batches of masterbatch (such as some masterbatch colors being dark and some being light), inconsistent density of filled masterbatch;

Cause: ① Insufficient mixing time (less than 15 minutes); ② Mixing sequence error (adding resin first and then powder, resulting in uneven powder wrapping); ③ The speed of the mixer is too low (below 500r/min), and the shear force is insufficient;

Solution: ① Optimize the mixing sequence: first add dispersant+lubricant → add functional powder (pre disperse for 10 minutes) → load resin (mix for 15-20 minutes); ② Adjust the speed of the mixer to 600-800r/min to ensure shear dispersion; ③ After mixing, sampling and testing should be carried out until the color/density is uniform before entering the extrusion process.

II. Melt extrusion process: core molding issues (affecting the appearance and intrinsic properties of masterbatch)

1. Insufficient plasticization (under plasticization)

Performance: The surface of the masterbatch is rough and has a granular feel, and small resin particles that have not melted can be seen on the cross section. It is easy to block the mold head during subsequent processing;

Cause: ① The extruder temperature is set too low (5-10 ℃ lower than the melting point of PE, such as LDPE not reaching 120 ℃); ② The length to diameter ratio of the screw is too small (<28), and the plasticizing stroke is insufficient; ③ The screw speed is too slow (below 100r/min), resulting in insufficient heat generation during shearing; ④ The filler content is too high (>70%), and the resin cannot be completely wrapped;

Solution: ① Heat up according to the resin type (LDPE 120-140 ℃, HDPE 140-160 ℃, LLDPE 130-150 ℃), with the mold head temperature 5-10 ℃ higher than the end of the barrel; ② Increase the screw speed to 120-180r/min to increase shear heat generation; ③ The filler content should be controlled below 70%, and if it exceeds the limit, the proportion of carrier resin should be increased; ④ If the aspect ratio of the equipment is insufficient, 0.5% -1% plasticizer can be added to assist plasticization.

2. Resin degradation (over plasticization)

Performance: The color of the masterbatch turns yellow/black, with a pungent odor (small molecule volatiles), and the mechanical properties decrease (easy to crack);

Cause: ① Excessive extrusion temperature (above 30 ℃ above the melting point of PE); ② The screw speed is too fast (>200r/min), resulting in excessive heat generation during shearing; ③ Carbon deposits inside the barrel have not been cleaned up, resulting in high-temperature decomposition pollution; ④ Insufficient amount of antioxidant (<0.5%);

Solution: ① Reduce the temperature by 5-10 ℃ and check if the temperature sensor is malfunctioning; ② Reduce the screw speed to below 150r/min to balance plasticization and degradation; ③ Shutdown and clean the machine barrel and screw (rinse with PE wax and cleaning material); ④ Add antioxidant (1010/168 compound, total amount 0.8% -1.5%).

3. Melt fracture (unstable casting)

Performance: The surface of the extruded material strip is uneven, wavy, and even fractured, making it difficult to cut particles smoothly;

Cause: ① The mold head temperature is too low, resulting in poor melt flowability; ② The gap between the mold mouth is too small (<2mm), resulting in high resistance at the melt outlet; ③ Fluctuations in screw speed and unstable melt pressure; ④ Insufficient dispersant/lubricant, excessive friction coefficient of the melt;

Solution: ① Raise the mold head temperature by 5-10 ℃ to ensure smooth flow of the melt; ② Adjust the gap between the mold mouth to 2-3mm and match the diameter of the material strip; ③ Check the screw drive system and eliminate speed fluctuations; ④ Add 0.5% -1% lubricant (such as stearamide) to reduce melt friction.

4. Blockage of mold head

Performance: The extruded material strip suddenly becomes thinner and breaks, and there is a buildup of burnt material at the mold mouth;

Cause: ① Impurities (metal shavings, dust, coke) mixed in the raw materials; ② The carbonized material generated by resin degradation adheres to the mold mouth; ③ The functional powder is not completely dispersed, and large particles block the mold holes;

Solution: ① Raw material screening (filtered with a 40 mesh sieve) to remove impurities; ② Regularly clean the mold head (stop and wipe every 2-4 hours, or install an automatic mold cleaning device); ③ Optimize the mixing and plasticizing process to ensure complete dispersion of the powder.

III. Granulation and cooling process: appearance and molding stability issues

1. Irregular grain cutting (uneven length/burrs/adhesion)

Performance: The length deviation of the masterbatch is greater than 1mm, with burrs on both ends or multiple particles sticking together into blocks;

Cause: ① The speed of the granulator does not match the traction speed of the material strip (cutting short if the speed is too fast, cutting long if it is too slow); ② Insufficient cooling of the material strip (water temperature is too high>30 ℃), resulting in a soft surface and easy adhesion; ③ Uneven discharge from the mold mouth and uneven thickness of the material strip; ④ The cutting blade becomes dull due to wear and tear, resulting in burrs during cutting;

Solution: ① Synchronize the traction speed (1-3m/min) and the cutting machine speed (500-800r/min) to ensure uniform length (2-3mm); ② The cooling water temperature is controlled at 15-25 ℃, and the cooling time of the material strip is ≥ 30s (the length of the cooling water tank can be extended); ③ Adjust the gap between the mold heads to ensure consistent thickness of the material strips; ④ Replace the sharp cutting blade and adjust the distance between the cutting blade and the mold mouth (<0.5mm).

2. Hollow/Bubble Masterbatch

Performance: The cross-section of the masterbatch has hollow pores or tiny bubbles, which are prone to rupture during subsequent processing and affect the density of the product;

Cause: ① The raw materials are damp (moisture content>0.1%), and the water evaporates at high temperatures, producing bubbles; ② During extrusion, air is drawn into the melt (if there is no exhaust during mixing, or if the feeding into the hopper is not smooth); ③ Insufficient die pressure prevents the release of bubbles;

Solution: ① Thoroughly dry the raw materials (powder baked at 120 ℃ for 4 hours, resin baked at 80 ℃ for 2 hours); ② Install exhaust ports on the mixer and seal the extruder hopper to prevent air from being drawn in; ③ Increase the die head pressure (by reducing the die gap or increasing the screw speed) to promote the discharge of bubbles.

3. Brittle cracking of masterbatch (insufficient toughness)

Performance: Easy to break after cutting or during transportation, with a flat and non ductile cross-section;

Cause: ① Resin degradation (over plasticization), molecular chain breakage; ② Excessive filler content (>60%) and insufficient proportion of resin matrix; ③ No toughening agent added or insufficient dosage (modified masterbatch); ④ The cooling rate is too fast (water temperature<10 ℃), and the internal stress has not been released;

Solution: ① Optimize extrusion temperature to avoid resin degradation; ② Reduce the proportion of fillers and increase the amount of carrier resin used; ③ Modified masterbatch with 5% -10% POE/EVA toughening agent; ④ Adjust the cooling water temperature to 15-20 ℃, or use gradual cooling (first 25 ℃ and then 15 ℃) to release internal stress.

IV. Performance and subsequent usage issues (failure of masterbatch function or poor adaptability)

1. The functional effect is not up to standard (light color/poor flame retardancy/weak anti-aging)

Performance: ① Insufficient coloring power of color masterbatch (adding 5% still results in a lighter color); ② Flame retardant masterbatch does not meet UL94 V2 level; ③ The anti-aging masterbatch will become brittle after being used outdoors for 3 months;

Cause: ① Insufficient content of functional components (such as masterbatch carbon black<20%, flame retardant<40%); ② Uneven dispersion of functional components and insufficient local concentration; ③ Incorrect selection of additives (such as using rutile titanium dioxide as outdoor color masterbatch, poor weather resistance);

Solution: ① Increase the concentration of functional components (masterbatch carbon black ≥ 30%, halogen-free flame retardant ≥ 50%); ② Optimize dispersion process (increase dispersant, extend mixing time); ③ Correct selection (outdoor use of rutile titanium dioxide+UV531 light stabilizer, flame retardant use of magnesium hydroxide+zinc borate synergist).

2. Poor compatibility with PE products (delamination/precipitation)

Performance: After processing the mixture of masterbatch and pure PE, the surface of the product may frost, become sticky (due to the precipitation of additives), or exhibit delamination and cracking;

Cause: ① Inconsistent carrier resin and product PE type (such as LDPE carrier masterbatch for HDPE pipes); ② Excessive lubricant/dispersant (>5%), exceeding the resin’s load-bearing capacity; ③ There is a significant difference in polarity between the functional components and PE (such as glass fiber reinforced masterbatch without added compatibilizer);

Solution: ① Strictly match the carrier resin with the product PE; ② The amount of lubricant/dispersant should be controlled at 1% -3% to avoid excessive use; ③ Add 3% -5% compatibilizer (such as PE-g-MAH) to enhance interfacial adhesion.

3. Moisture absorption of masterbatchs (decreased performance after storage)

Performance: After one month of storage, the surface of the masterbatch becomes damp and clumped, and bubbles are generated during subsequent processing;

Cause: ① Insufficient drying after cooling (moisture content>0.1%); ② The packaging is not tightly sealed and absorbs moisture from the air; ③ Functional ingredients absorb moisture (such as calcium carbonate, magnesium hydroxide);

Solution: ① After cooling, dry again (drying at 60-80 ℃ for 1-2 hours, reducing the moisture content to below 0.05%); ② Sealed packaging with aluminum foil bag and desiccant; ③ Moisture absorbing functional powders (such as magnesium hydroxide) are pre modified with coupling agents for hydrophobic properties.

V. Key troubleshooting logic in the production process (quick identification of problems)

First, look at the raw materials: check the moisture content, powder dispersion status, compatibility between the carrier and additives, and eliminate potential hazards at the source;

Recheck the process: prioritize checking the temperature (barrel+die), screw speed, and mixing time, which are the core parameters affecting plasticization and dispersion;

Rear view equipment: Check the wear of screws/barrels, blade sharpness, and stability of cooling water temperature. Equipment failure can easily lead to batch problems;

Small scale validation: After encountering problems, make small batch formula adjustments (such as adding dispersants and adjusting temperatures) before mass production to avoid waste.

The core contradiction in the production of PE masterbatch is “dispersion uniformity+plasticizing stability+forming regularity”, and most problems can be solved through “raw material drying, formula matching, and process parameter optimization”. The key lies in: ① controlling the moisture content of raw materials to be less than 0.05%; ② Adaptation of functional ingredients to dispersant ratio (powder: dispersant=5:1-10:1); ③ Match the extrusion temperature with the resin type to avoid under molding or over molding; ④ Synchronize cooling and cutting parameters to ensure a neat appearance.

For mass production, it is recommended to establish a “raw material process finished product” testing ledger to record the parameters and performance of each production, facilitating quick traceability and troubleshooting of repetitive issues.

Applications

Polyethylene masterbatch is a polymer material based on polyethylene, with various functional additives or fillers added. It has a wide range of applications in the field of plastic processing. The following are some of the main application aspects:

BOPP

Agricultural film: a polyethylene film with added anti-aging, anti fog, insulation and other functional mother materials, which can be used for greenhouse covering, crop cultivation, etc. in agricultural production. Anti aging masterbatch can improve the weather resistance of the film and extend its service life; The anti fog droplet masterbatch reduces the formation of water droplets on the surface of the film, improves light transmittance and insulation effect, and is beneficial for the growth of crops.

Packaging film: Adding a smooth masterbatch to polyethylene packaging film can reduce the friction coefficient of the film surface, making it easier to roll and use the film; Adding anti-static masterbatch can prevent static electricity from forming on the surface of the film, avoid adsorbing dust and impurities, and improve packaging quality.

Pipe products

Water supply pipe: Polyethylene water supply pipes are added with environmentally stress cracking resistant masterbatch, which can improve the anti cracking performance of the pipes and ensure that they will not rupture due to environmental factors during long-term use. At the same time, adding color masterbatch can give the pipe different colors, making it easy to distinguish and identify.

Gas pipe: When producing polyethylene gas pipes, flame retardant masterbatch and UV resistant masterbatch need to be added. Flame retardant masterbatch can improve the flame retardant performance of pipes and enhance safety; UV resistant masterbatch can prevent pipes from aging due to long-term exposure to ultraviolet radiation outdoors, extending their service life.

Injection molding products

Plastic containers: Adding toughening masterbatch to polyethylene injection molded plastic containers can improve their impact resistance and make them less prone to breakage during use; Adding filler masterbatch can reduce production costs while improving the rigidity and hardness of the container.

Turnover box: Polyethylene turnover boxes are often added with wear-resistant masterbatch to improve their surface wear resistance, reduce wear during frequent use and handling, and extend the service life of turnover boxes.

Fiber products

Polypropylene fiber: Adding polyethylene masterbatch in the production of polypropylene fiber can improve the dyeing performance, anti-static performance, and softness of the fiber. For example, adding dyeing masterbatch can make fibers easier to color, with bright and firm colors; Adding anti-static masterbatch can eliminate the static electricity generated by fibers during processing and use, improving processability and user comfort.

Non woven fabric: Polyethylene non-woven fabric contains anti sticking masterbatch, which can prevent fibers from sticking to each other during the production process, improve production efficiency and product quality; Adding hydrophilic masterbatch can make non-woven fabrics have good water absorption and breathability, suitable for fields such as hygiene products and medical supplies.