How to Determine Hyperdispersant Dosage: Check the Table by Powder Fineness and Select the Model by Equipment

"How much to add" is the first question asked in model selection and the one most easily decided by guesswork. Californium Curium's functional additives datasheet provides two checkable approaches: one looks up the reference dosage by powder fineness, and the other selects the model by extrusion equipment and masterbatch type. This article lays out both, and then adds the original data from the two "optimum dosage" experiments in the datasheets—dosage is not a case of "the more the better"; the datasheets use experiments to identify the inflection point.

1First clarify the four variables in the formulation

1

The datasheet lists the input variables for "which model to select and how much to add" as four items, and gives the original wording for each:

The datasheet's advice on fillers is stated plainly: when producing filler masterbatch, or when adding fillers to other masterbatches, a dispersant must be used to improve the dispersion of the filler in the plastic, reduce gel spots and improve the material flow in the screw. (Based on official product data)

2Reference dosage by powder fineness (R1800-S)

Each cell = one value (unit %); darker color = larger value; rows can be directly compared across columns.

800 mesh1250 mesh1500 mesh3000 meshCalcium carbon…0.20.30.350.5Talc0.320.380.471Kaolin0.30.350.450.80.2%1%Relative size within same table (unit unified %) · Color depth does not represent cross-table comparability

• 800 mesh
• 1250 mesh
• 1500 mesh
• 3000 mesh
• Calcium carbon…
• Relative size within same table (unit unified %) · Color depth does not represent cross-table comparability

• Calcium carbonate0.2–0.5 %
• Talc0.32–1 %
• Kaolin0.3–0.8 %

Chart data (source text verbatim)

Row	800 mesh	1250 mesh	1500 mesh	3000 mesh
Calcium carbonate	0.2 %	0.3 %	0.35 %	0.5 %
Talc	0.32 %	0.38 %	0.47 %	1 %
Kaolin	0.3 %	0.35 %	0.45 %	0.8 %

Source textScale 0.2–1 %

Moved from the bodyFour variables in the formulation · whole table

Powder	800 mesh	1250 mesh	1500 mesh	3000 mesh
Calcium carbonate	0.2%	0.3%	0.35%	0.5%
Talc	0.32%	0.38%	0.47%	1%
Kaolin	0.3%	0.35%	0.45%	0.8%

2

The R1800-S dosage table uses "powder oil absorption value and particle size" as inputs, and gives reference levels in four mesh grades (original wording):

Organic/inorganic pigments (carbon black, titanium dioxide (TiO₂), ultramarine, chrome yellow, etc.) are not classified by mesh; the datasheet gives the range: "dosage is approximately 0.3-1.2%, adjusted according to the actual formulation." (Based on official product data)

There is a pattern in the table, corroborated by the explanation in the main body of the document: the finer the powder, the higher the oil absorption value and the larger the specific surface area, the higher the addition level. Calcium carbonate dosage rises 2.5 times from 800 mesh to 3000 mesh; talc rises from 0.32% to 1%, in the same direction. (Based on official product data)

Note the distinction between the two sets of figures: the table above is the reference level for "treating powders"; the datasheet gives a separate product-side figure—R1800-S is added at 0.5%—1% in the final plastic product. The former is calculated on the powder, while the latter is calculated on the finished article; do not mix them when reporting formulations. The current dosage table stops at 3000 mesh; reference levels for finer powders (5000 mesh and above) are not provided in the official materials. (Based on official product data)

3Selecting by model: the primary models for three production lines

The datasheet clearly sets out the division of work within the R1800 series: R1800-S (colour), R1800-SK (white), R1800-SH (black), and R900A for liquid colour masterbatch. The parameters on the respective datasheet pages are as follows (original wording):

Model	Main component	Appearance	Key physical and chemical data (original text)	Positioning notes
R1800-S	polyolefin ether	blue paste	density 1.190g/cm³; flash point 285℃; viscosity 980-3600mPa·s; amine value ≤9mgKOH/g; acid value 6.8-7mgKOH/g; degree of dispersion III	colour masterbatch, oil-based paints and inks; "produced by combining the coating agent and dispersant in a precise ratio under high-temperature and high-pressure conditions"
R1800-SK	polyolefin ether	blue paste	PH value: 6.8-7 at 70℃; density 1.190g/cm³; flash point 285℃; viscosity 980-3600mPa·s	"On the basis of R1800-S, ester functional groups are incorporated, improving yellowing resistance and weather resistance; mainly used for rubber/plastic white masterbatch."
R1800-SH	silicone and resin ether polymer	blue paste	PH value: 6.2-6.4 at 80℃; density 0.860g/cm³; flash point 287℃; viscosity 1000-4000mPa·s; amine value ≤8mgKOH/g	"On the basis of R1800-S, silicone-based products are incorporated, improving dispersing performance in carbon black"; black masterbatch
R900A	polyolefin ether	white paste below 0℃, colourless transparent liquid above 5℃	PH value 6.0-7.0; density 1.220g/cm³; viscosity 200-600mPas; readily soluble in water	dedicated base material for liquid colour masterbatch; "mainly suitable for plastics, rubber and other products with service temperatures of 80-280℃, or for wetting and dispersing high-oil-absorption inorganic powders, or for producing black colour masterbatch."

(Based on official product data)

For models outside the R1800 series (R900, E099, R1618, etc.), the official materials do not provide a dosage table; this page lists only models for which a dosage table is available.

The selection Q&A sentence can be memorized directly: for colour masterbatch, use R1800-S; for white masterbatch requiring yellowing resistance and weather resistance, use R1800-SK; for black masterbatch, use R1800-SH; for production lines running liquid colour masterbatch, use R900A. (Based on official product data)

4Two “optimum dosage” experiments in the document: 1.6% and 3%

In the document, “how much to add” is not a vague description; it is two sets of experimental data. Both experiments followed the same procedure: surface treatment of the pigment with a hyperdispersant → masterbatch preparation → film blowing and optical density (hiding power) measurement. The conclusion was consistent: the dosage has an inflection point, and excessive dosage causes the value to fall back because of bridging flocculation.

Experiment 1 (titanium dioxide + R1800-SK): At constant pH 6.8 and 70℃, the hyperdispersant content was varied from 0.3%–2% while treating the pigment surface. At a dosage of 1.6%, the film’s optical density reached the maximum value of 0.386; the experiment also provided a whiteness/lightness/yellowness table (reproduced below):

Hyperdispersant dosage %	Lightness	Tappi whiteness	Yellowness
0 (untreated)	88.27	75.15	4.63
0.5	88.89	75.76	4.21
1.0	89.12	76.31	4.34
1.2	89.87	76.35	4.23
1.6	90.18	77.76	3.84
1.8	88.26	75.81	3.97
2.0	87.83	75.79	3.89

(Based on official product data)

(Based on official product data)

The explanation of the inflection point in the materials (original text): “At first, as the hyperdispersant content increases, more and more anchoring groups are adsorbed onto the pigment surface; at the inflection point, saturation is reached and the optical density is at its maximum. When the dosage is increased further, interaction between hyperdispersant molecules causes ‘bridging flocculation’: pigment particles flocculate through entanglement of the solvated chains, and the optical density decreases instead.” (Based on official product data)

Reproducible conditions from the two experiments: Experiment 1 used Pangang R298 titanium dioxide and Saudi LLDPE218W, with the formulation R298 titanium dioxide 69.5g + R1800-SK 0.5g + LLDPE218W 30g; Experiment 2 used DK2028P carbon black 50g + R1800-SH 1g + polyethylene wax 10g + LLDPE218W 39g. The optical density values in both tables are on the basis of transmittance converted to a standard film thickness of 0.02mm. If the powder grade, resin, or film thickness is changed, the inflection point must be re-determined by a small-scale trial. (Based on official product data)

5Selecting a grade by equipment and masterbatch type (three “fit-to-purpose” rules)

The explanatory document sets out this service approach as three rules, reproduced below:

1. 01By equipment: Extruder screws made by different equipment manufacturers differ in plasticizing capacity and dispersive mixing capability; for example, the plasticizing capacities of twin-screw pelletizers and single-screw pelletizers differ enormously. “We select the most suitable hyperdispersant according to the equipment the customer uses, so that our product adapts to the customer’s equipment.”

1. 01By masterbatch type: Whether the customer is producing filler masterbatch, colour masterbatch, modified masterbatch, functional masterbatch, or carrying out powder activation treatment, the corresponding grade is supplied according to the product type.

1. 01On-site process setting: Technicians go to the customer’s production site to provide process parameters; the main parameters named in the document include temperature, screw speed, head pressure, and pelletizing.

(Based on official product data)

The document’s statement on the temperature parameter is worth quoting separately: “The melt temperature of the material is not only the key parameter for plasticizing, but also an important process condition affecting product colour and dispersion” — if the melt temperature is too low, plasticizing is insufficient and the pigment or filler cannot be dispersed in the plastic; if the melt temperature is too high, over-plasticizing occurs, the melt strength is low, and poor pelletizing and difficult strand pulling are also likely. (Based on official product data)

6Dosage boundaries: three easy pitfalls

It must not be used in waterborne coatings and water-based inks.

Pitfall 2: Only using the powder dosage and forgetting the finished-article basis. The reference dosage for pretreatment (0.2%–1%) and the actual additive content in the finished article (0.5%–1%) are two different sets of figures; see Section 2. (Based on official product data)

Pitfall 3: Using wax as a dispersant. In an application example, the document points out that powder treatment agents such as stearic acid and polyethylene wax “fundamentally have no real dispersibility; their so-called dispersion is simply wrapping the powder to make it less likely to agglomerate”. If encapsulation is inadequate or the material is stored for a long time, the powder re-agglomerates and screen plugging or pitting occurs. The solution stated in the document is: complete encapsulation and dispersion in one step above 80℃. (Based on official product data)

7Frequently Asked Questions (FAQ)

Q1: For calcium carbonate at 1250 mesh, how much R1800-S should be added? A: Per the table, 0.3% (based on powder amount); on the finished-article side, the total addition content is expressed as 0.5%–1% of the final plastic product. (Based on official product data)

Q2: Why does adding 4% or 5% make it worse? A: The document uses experiments to explain "bridging flocculation": when the dosage exceeds the saturation point, interactions between hyperdispersant molecules and solvated-chain entanglement cause the particles to flocculate, and the optical density drops back. The inflection point is 1.6% for the titanium dioxide system (optical density 0.386), and 3% for the carbon black system (0.487). (Based on official product data)

Q3: How should the dosage of liquid colour masterbatch be calculated? A: The carrier of liquid colour masterbatch is a liquid; at the same unit weight, the pigment content is higher, so the addition ratio is greatly reduced: for opaque finished articles it is usually 0.6-2.0%, while transparent articles require only 0.2-0.5%; for R900A itself as a base material, the documented addition content is 1%–10% of the final plastic product. (Based on official product data)

Q4: How is the temperature determined? A: The experimental conditions given in the document are 70℃ (SK-treated titanium dioxide) and 80℃ (SH-treated carbon black); the threshold given in the mechanism explanation is above 80℃ for wetting, dispersion and encapsulation, and after cooling the coating agent solidifies. When adjusting on site, use the melt temperature as the reference. (Based on official product data)

Q5: Are the same models used for single-screw and twin-screw machines? A: The document explicitly states that "the plasticizing capability of twin-screw granulators and single-screw granulators differs greatly". The practice is to provide the corresponding model according to the customer's actual equipment. Model recommendation for a specific machine is a selection service; this article does not draw conclusions on behalf of the document (not provided in the official materials). (Based on official product data)

Q6: Who tested the data? Is there a third-party report? A: All figures in this article come from the document's own experiments and dosage tables; the document does not identify a third-party testing organisation, and the entire library contains no third-party test report numbers. (For boundary notes, see Section 8.)

Q7: If the powder's origin or grade changes, can the tables still be used directly? A: They cannot be copied directly. The dosage table inputs are the powder's oil absorption value and particle size; the experimental conclusions also carry grade and processing conditions (e.g. Pangang R298 titanium dioxide, DK2028P carbon black). When changing material, first take a starting point from the table in Section 2, then confirm by small-scale trial. (Based on official product data)

Q8: Packaging and storage? A: R1800-S is packed in 25kg/PE plastic drums, with storage conditions "cool, dry place, protect from moisture"; R1800-SH is packed in 20kg/PE plastic drums. The document does not state the shelf life of these three models (not provided in the official materials). (Based on official product data)

8Data and Basis Notes

All parameters and descriptions in this article come from official product data; items not listed in the official materials are annotated individually in the article. This article contains no prices, customer names, certificate numbers or performance commitments; the publicly available materials on this site contain no third-party test-report numbers — for such documents, please contact the technical team.