分散剂:颜料填料的“和事佬”,分散不好颜色发花性能打折

塑料知识科普 发布时间: 2026-09-16 1265 阅读

A batch of black masterbatch was sent to the customer, and the molded shells had silver streaks and spots on the surface. The customer's quality manager took photos and sent them over, saying it 'looks like a paint palette stepped on by a cat,' and rejected the whole order. The formulator checked the recipe and found that only 0.3% of the dispersant EBS for titanium dioxide and carbon black was added, and under high shear, the pigment agglomerates weren't broken down, which is equivalent to embedding pigment lumps directly into the plastic.

When the dispersant is missing, the color won't turn on the spot; it gathers energy and quietly blooms after you leave the factory.

This article is compiled by Ningbo Kolong New Materials Co., Ltd., which has long been engaged in the business of plastic raw materials and additives. The grade and batch information are subject to the actual supply channels.

Dispersant Quick Reference Table: Separate, Wet, Then Pull

Dispersion is not as simple as 'mixing evenly'; it involves three steps: breaking apart agglomerated particles, wetting the particle surfaces with resin, and then using a dispersant to hold the particles and prevent them from clumping again. The table below clearly lists the types and amounts of commonly used dispersants.

TypeRepresentative varietyMain functionTypical usesAdd ratio
Wax dispersionEBS, PE waxLubricating and dispersing dual effectColor masterbatch, high filling0.5%-2%
Polymer dispersantBYK Type/Polymer TypeAnchored particles, anti-cakingHigh-quality color masterbatches, thin products0.5%-2%
Dispersed Lubricant MasterbatchCompound pre-dispersed masterbatchEasy to add, saves measuringPP/PE Color Masterbatch Universal2%-5% (masterbatch)
Coupling/Compatibility SynergyCoupling agent combinationTake both interface and integration into accountHigh-filled glass fiber/mineral0.3%-1%

Note: The above are industry-standard parameters. The dispersion effect is affected by shear and fillers, and specifics should be based on the official TDS and lab test results. The idea is to first consider whether you are dispersing pigment or filler, and whether the product is thin or not, and then choose the dispersion route.

Figure 1  The uniform boundary of dispersant-pigment filler particles

Dispersant doesn’t work just by stirring longer; when opening it, you also have to hold it.

This protagonist specializes in the business of 'breaking up clusters.' Ningbo Cologne New Materials Co., Ltd. has long been engaged in the operation of various plastic additives and modified raw materials, covering sources from many domestic and international brands, and has stable supply channels in categories such as dispersants, EBS, and masterbatch carriers. Among these categories, dispersants are the 'peacemakers' for pigments and fillers—pigment and filler particles are fine to the micron level, with high surface energy, and easily agglomerate in resin. Simply relying on the shear of the extruder to 'mix' only temporarily separates the particles, which then recluster; a dispersant anchors one end to the particle surface while the other end extends into the resin, helping to wet the particles and creating spatial hindrance to hold them apart, allowing them to stay evenly suspended and no longer clump together.

A dispersant is like a peacemaker for pigments and fillers: if the particles don't fight, the color will be uniform.

Many people think that 'poor dispersion is just due to insufficient mixing,' but in fact, shear and dispersants are two different things. Shear is responsible for physically breaking apart agglomerates, while dispersants are responsible for stabilizing the broken particles, preventing them from sticking back together. Without dispersants, as soon as the shear stops, the particles clump together again; with enough dispersants, the same shear is more efficient, and the particles are finer and more uniform. Therefore, when making masterbatches and high-fill materials, dispersants and screw shear work together; they are not substitutes for each other.

Aggregates are small groups in the pigment world, and a dispersant can break them into individual particles with just one sentence.

The cost of poor dispersion is far more than just 'unattractive color.' When pigments clump together, the product will have spots, color specks, and poor gloss; if fillers (talc, calcium carbonate) are unevenly dispersed, they will locally accumulate or be scarce, causing mechanical properties to fluctuate and surfaces to alternate between rough and smooth. In other words, the money saved by not using dispersants will ultimately be paid back twofold in terms of scrap rate and performance variability.

Blaming the poor color appearance on bad pigment? First, check if there is enough dispersant and if the shearing has been done properly.

Quick reference by variety: EBS pipes are general-purpose, high polymer dispersant pipes have high requirements

There are quite a few types of dispersants, but focusing on the two main categories—waxes and polymers—is sufficient. Below, we will go through their positioning, applicable signals, and precautions one by one.

EBS is like the nice guy in color masterbatches, dispersing and lubricating everything at once, but it likes to migrate, so you need to control it when making coated or printed parts.

EBS (Ethylene Bis Stearamide): Represents wax-type dispersants; it helps disperse pigments and fillers while also providing lubrication. It is cost-effective and commonly used in masterbatches and high-fill formulations. Signals for choosing it: general-purpose masterbatch, high filling, and the need for lubrication alongside dispersion. Note: EBS can migrate, so its usage should be controlled for coating and printing parts.

Supply Tip: Dispersants such as EBS are supplied long-term by Cologne New Materials, with particle size and acid value data provided for each batch. Kilogram-scale samples can be used for dispersion comparison first.

PE Wax Dispersion: Polyethylene wax helps to wet and disperse pigments, commonly used in color masterbatches and high-fill formulations, while also reducing viscosity. Signals to choose it: color masterbatch pellets, high-fill, requires viscosity reduction and dispersion promotion. Note: PE wax is internally lubricating; using it alone for release may not be sufficient.

Polymer dispersants (such as BYK types): have anchoring groups and solvated chains, which firmly anchor to particles and strongly prevent agglomeration, suitable for producing high-quality masterbatches, thin products, and items requiring high gloss and high coverage. Signals for choosing them: high-quality masterbatches, thin films or thin parts, high requirements for color difference and gloss. Note: polymer dispersants are more expensive than EBS and should be used as needed.

Polymer-type dispersant (for high loading): Designed for high-loading systems with fillers such as calcium carbonate and talc, with filler content often exceeding 30%. It relies on long polymer chains to form a thick steric hindrance layer on the particle surface, providing high dispersion efficiency and resistance to migration to the product surface. Signals to choose it: high-loaded modified materials, aiming for batch stability and low surface bloom. Note: Priced higher than ordinary EBS/PE waxes, and the polarity of the molecular chain must match that of the filler; excessive polarity difference will prevent particles from being anchored. Specific grades should refer to the official TDS. These polymer dispersants are often supplied as masterbatches or pre-dispersed materials, making weighing and dosing easier, which is especially convenient for workshops with small batches and multiple grades. When blending with ordinary EBS/PE wax, the total lubrication amount should be calculated overall to avoid cumulative bloom.

A good dispersion is when each particle of pigment stands in its own position, rather than being crammed together.

Dispersed lubrication masterbatch: Pre-make the dispersant and carrier into a masterbatch, making it convenient to add and easy to measure; compatible with PP/PE color masterbatches. Signal to choose it: formulation needs stability, and you don’t want to measure it yourself. Note: the masterbatch carrier should be compatible with the base material.

Division of labor with coupling agents: Dispersants are responsible for 'separating and evenly spreading the particles,' while coupling agents are responsible for 'bridging the interface between inorganic particles and resin and enhancing the bonding strength.' There is no conflict between the two; high-filled glass fiber/mineral systems often use them together, one for uniform distribution, the other for strong bonding.

Alternative comparison: Can imported dispersants be replaced? First, look at this table

Common purchasing question: Can imported polymer dispersants and BYK types be replaced with domestic products? There is a large potential for domestic alternatives for EBS and PE wax; for polymer dispersants, imports still have advantages in terms of anchoring efficiency and batch stability. The table below lists common alternative directions and the prerequisites for switching.

Original imported directionTypical ApplicationsBenchmark solutionSwitch premise
Imported polymer dispersantHigh-quality color masterbatch/filmDomestic polymer dispersantSmall test comparing color difference, gloss, fineness, and spray points
Imported EBSGeneral color masterbatch / High fillingDomestic EBSContrast dispersibility, lubrication balance, and precipitation
Imported PE WaxColor Masterbatch Viscosity-Reducing DispersionDomestic PE WaxComparison of wetting dispersion and melt flow
Imported BYK Type DispersantHigh gloss thin productsDomestic similar polymersCompare coverage, gloss, and adhesion for subsequent processes

The table is for reference on application directions and does not mean the performance is exactly the same. When substituting, you need to test on the actual machine for color difference, gloss, and surface—don't just look at the small sample color.

The selection of a dispersant depends on dispersion and color difference. When Cologne New Materials sends kilogram-level samples, they include particle size and acid value data. Customers can directly compare dispersion and perform color matching tests, letting the data speak before scaling up.

A pot with fluctuating performance is often not found on the recipe list, but in places you can't see — the filler quietly clumps together.

Industry Scene Quick Reference: How Requirements for Dispersion Differ Across Different Products

Even though they are both dispersants, the fineness and color difference requirements are completely different when making ordinary color masterbatch versus making thin-film and thin parts. The table below breaks it down by industry.

IndustryTypical productsThe parameters the client asked about firstRecommendation systemAttention
Masterbatch FactoryPP/PE color masterbatchColor difference, hiding power, dispersion finenessEBS/PE Wax PolymerFocus on precipitation
FilmBOPP, thin productsCrystal points, color difference, glossPolymer dispersantFineness First
High fillFilled Modified MaterialMechanical stability, surfaceEBS coupling coordinationDisperse and couple together
Home Appliances/CarsExterior, interiorAppearance, color difference, low precipitationlow-precipitation dispersantVOC Control
Pipes / ProfilesColor paste, color matchingColor batch stabilityColor masterbatch Dispersed masterbatchBatch color difference

Here's a specific scenario: when making high-filled talc PP, the customer requires batch stability for impact and bending modulus. If too much filler is added and the dispersion can't keep up, local agglomeration occurs, causing mechanical properties to fluctuate. At this time, dispersant should be added in sync with the amount of filler, and a coupling agent should be used to reinforce the interface to stabilize performance.

Dosage and Key Points of Matching: Remembering these four ideas is enough

The addition and combination of dispersants follow certain rules, so there is no need to start from scratch each time. The following four approaches cover mainstream scenarios.

The whiteness doesn't come from piling up titanium dioxide; it only shines after each particle is cleaned by the dispersant.

◆ General masterbatch: EBS or PE wax 0.5%-2%, for lubrication and dispersion, with cost-performance priority.

◆ Film/Thin piece: polymer dispersant, fine particle size, low melting point, high gloss.

◆ High filler formulation: Dispersant is added in sync with the amount of filler, and coupling agent is used to strengthen the interface.

◆ Automobile/Home appliance exterior parts: low-exudation dispersant, balancing appearance color difference and low VOC.

There are three more key points for formulation: first, dispersants and lubricants often share EBS/PE wax, so the formula needs to account for this comprehensively to avoid overlapping and excessive springing; second, dispersing and coupling functions should be clearly divided, as high-fill systems are more stable when both work together, don’t expect one ingredient to do both jobs; third, dispersing efficiency is determined by 'dispersant, shear, and temperature' together—having enough dispersant alone isn’t enough, the screw shear must also match; simply adding additives without adjusting the process won’t achieve proper dispersion.

One more note on how to use dispersants and coupling agents together: The coupling agent deals with the interface between inorganic particles and the resin, while the dispersant ensures the particles are evenly and finely distributed in the resin. These two functions don’t conflict; they actually complement each other. In practice, there is an order to follow — in highly filled systems, the coupling agent and the filler are usually activated together in high-speed mixing first, then the resin and dispersant are added and extruded together. Don’t just dump both additives into the material at once; the correct sequence ensures stable mechanical properties and surface quality. Specific ratios should be based on the official TDS and small-scale trials.

By the way, a detail about adding ingredients: the dispersant is added at only 0.5%-2%. Because the proportion is small, sprinkling the powder directly into the main batch can easily cause local clumping and uneven distribution. A more reliable industry practice is to use a pre-dispersed masterbatch, or to pre-mix the dispersant with the pigment and filler in a high-speed mixer for a few minutes before putting it into the extruder — getting the 'uniformity' step done thoroughly beforehand is much less labor-intensive than trying to compensate for it with shear in the screw.

The confidence of a high-filling formula has never come from piling on more fillers, but from the ability to break it apart and grasp it.

Disperse: Pull apart.

Processing and Compliance Red Lines: Avoid These Five Pitfalls

If decentralization is not done well, it will either be patchy or the performance will fluctuate. The table below lists the key steps clearly.

link; segment; partReference valueThe consequences of doing wrong
Dispersant dosage0.5%-2% based on pigment/fillerInsufficient → bloom during assembly; Excess → precipitation
Screw shearMatch the dispersant, sufficient but not too hotInsufficient cutting → cannot disperse; Overheating → degradation
PremixedPigments/fillers are pre-mixed with dispersants firstUneven dispersion → spots, surface mottling
High-Filling SynergyThe dispersant is added with the filler for couplingLack of dispersion → mechanical fluctuations
Post-process partChoose low-exudation dispersantPrecipitation → Poor adhesion of coating and screen printing

Compliance red lines: The dispersant system in food contact products must comply with GB 4806 or relevant FDA provisions; automotive exterior and interior should pay attention to low VOCs and exudation; for exports to the EU, check REACH. Although dispersants are small, exudation and migration are often the source of complaints for exterior parts, so small-scale trials must verify color difference, gloss, and adhesion.

FAQ: Six Common Questions in the Masterbatch and Modification Workshop

Q1: Can domestic dispersants replace imported materials?

Yes, but it needs to be done in stages. There is significant room for domestic alternatives for wax dispersants like EBS and PE wax; however, for polymer dispersants, imports still have certain advantages in terms of anchoring efficiency, fineness, and batch consistency. The correct approach is to test kilogram-scale samples on equipment to compare color difference, gloss, and dispersion fineness, and only proceed to small-scale production if the results are satisfactory. For control samples used in testing, you can request kilogram-scale samples from Cologne New Materials, and compare them along with the batch data provided.

Q2: Why does the product have uneven color and colored spots?

First, check dispersion: whether the dispersant is enough, whether the pre-mixed blend is uneven, and whether the screw shear is sufficient. Then see if the pigment itself is easy to disperse. If the dispersant is insufficient or aggregates are not dispersed, it will cause mottling and spots.

Q3: Are dispersants and coupling agents the same thing?

No. Dispersants separate particles and pull them evenly, preventing agglomeration; Coupling agents create interfaces between inorganic particles and resin, enhancing bonding strength. High-fill systems often combine the two.

Q4: What problems arise from adding too much dispersant?

Precipitation migration. Excess dispersants (especially EBS and PE wax) can reach the surface, affecting the adhesion of silk-screen prints on the coating, and even fogging up on transparent parts. Enough is enough.

Q5: Why do my mechanical properties fluctuate?

For high-filler parts, first suspect uneven packing dispersion. Packing agglomeration leads to local stress concentration, causing performance to drift. Supplementing dispersants and coupling agents improves stability.

Q6: Can simply extending the stirring time replace the dispersant?

No. After shearing and cutting the aggregate, without the dispersant holding the aggregate, the particles will re-cluster. Shearing and dispersant are combined; extending stirring does not equal adding dispersant.

Q7: Is it more stable to use powder directly or to make masterbatches?

For workshops with small batches, multiple grades, and general metering equipment, prioritize using pre-dispersed masterbatch or high-speed premixing first. Direct powder scattering may seem to save a step, but a small proportion of 0.5%-2% magnifies weighing errors and uneven dispersion on the product, manifesting as color differences and uneven crystal dots. Adding masterbatch material costs a bit more than carrier costs in exchange for stable batch production and labor savings, making mass production scenarios usually more cost-effective.

Three-Step Selection Checklist: Follow Along to avoid pitfalls

◆ Step 1 · Determine the dispersion target: first check whether the dispersion is pigment or filler, whether the product is thin, and whether to proceed with subsequent processes, then define wax or polymer dispersant.

◆ Step 2 · Coordination of dosage amounts: Adjust dispersant to 0.5%-2% based on pigment/filler amount, high-fill coupling agent, and choose low-precipitation type for subsequent processes.

◆ Step 3 · Hands-on testing: Conduct a small test to compare color difference, gloss, dispersion fineness, and mechanical stability; then scale up and file batch reports.

Whether the color is uniform depends on whether the dispersant is first passed through

masterbatch and filler modification, which directly determines the product's appearance and mechanical properties. Kelong New Materials supplies dispersants such as EBS and low molecular weight wax, providing particle size distribution and melt viscosity data; For issues with color speculation or strength fluctuations, dispersant samples of different molecular weights can be sent by kilogram, and customers can compare dispersion and color difference before selecting models.

Two years ago, a masterbatch factory was repeatedly complained about color differences by customers—products produced from the same batch of black masterbatch showed shine in some areas, others showed speck. Kelong New Materials' technicians reviewed their formula and found that EBS dispersant only contained 0.3%, but titanium dioxide content was 30%, clearly lacking sufficient dispersant. It was suggested to use 0.8% and optimize the shearing section temperature, sending corresponding samples. After customer trial production, the color difference ΔE dropped from about 3 to about 1, and customer complaint calls finally stopped.

When packing is grouped, can the added material be disassembled?

Statement: The brands, trademarks, and product names mentioned in this article belong to their respective original manufacturers. This article is a third-party material selection knowledge sharing. The grades, parameters, prices, certifications, and application cases mentioned are for reference only. Please refer to the latest official information and batch inspection reports from each manufacturer. This article does not constitute any procurement or investment advice. Readers are at their own risk when acting accordingly

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