Will the powder disperse in your compound?
Check rubber powder at three stages: the incoming material, its distribution after mixing, and the finished part. A sieve result describes size distribution before mixing; it does not prove even dispersion in your formulation. The compounder must choose the trial, processing conditions and acceptance tests. No universal mixing recipe or replacement rate follows from a mesh label.
Explore the questionsFollow the powder through the trial
- 1 · Incoming powder
Size distribution and sample identity Question: what entered the trial?
- 2 · Mixed compound
Distribution, clusters and process records Question: did it spread as intended?
- 3 · Finished part
Appearance and application tests Question: does the result meet the brief?
Size is not dispersion
A compliant incoming sieve curve does not show where rubber particles end up after processing.
Keep the comparison fair
Record formulation and process conditions so a material change is not confused with a mixing change.
No automatic finer-is-better rule
Ask which size and distribution your formulation needs. Bedrock's suitable grade, sample quantity and supporting information require confirmation.
Applications
Choose the question you want to explore.
Why can a good sieve result still leave a mixing problem?
Particle size and particle distribution answer different questions.
Start with the incoming sieve curve, but do not stop there. A powder can meet a size requirement while its particles distribute unevenly in the polymer or compound.
In Basso and colleagues’ ground-tyre-rubber/polypropylene study, rubber distribution varied across injection-moulded samples. Local concentration differences were associated with differences in surface finish and hardness. That result concerns the researchers’ materials and moulding conditions, not every rubber formulation or Bedrock powder. Its buying lesson is narrower: check the processed material as well as the incoming powder.
Are a large particle and a cluster the same thing?
An agglomerate is a group of particles, not necessarily one coarse particle.
Particles can group together. In Hrdlička and colleagues’ original GTR study, the researchers observed agglomeration while sieving some waterjet-produced samples and considered it a likely reason for their coarser apparent distribution. The observation does not show that Bedrock material behaves that way.
If your laboratory sees lumps or clusters, record where they appeared: in the supplied powder, during sample preparation, or after processing. Ask the laboratory how its examination distinguishes a cluster from an individual particle. Do not silently break up or otherwise condition one sample differently from the comparison sample. The agreed method and any preparation belong in the trial record.
How do you make two powder trials comparable?
Change deliberately and record what stayed the same.
Have the compounder define a reference formulation and the performance questions before selecting the material. A useful comparison record includes:
- The powder sample or lot identity and available size information
- The base formulation and the powder addition used in each trial
- The mixing and forming conditions chosen by the technical team
- Where samples were taken and how distribution was examined
- The agreed finished-part checks and results
This is a planning checklist, not a production recipe. If the team changes material and processing together, label that as a combined change. Do not attribute every difference to particle size alone.
Which result should decide the purchase?
Use the requirements of the actual part, not a powder photograph.
Ask the responsible technical team to set acceptance criteria for the application. Depending on the product, its checks may include appearance, consistency between sampled locations and relevant mechanical or processing requirements. A visually smooth part does not by itself establish the required performance.
For a rubber-powder enquiry, send the formulation type, required grading, intended evaluation and sample quantity. Bedrock can discuss the material and information available for that trial. Availability of a particular fine grade, test report or production quantity must be confirmed; this guide does not promise a ready-approved compound ingredient.
Plan a powder trial around your process
Send your required grading, compound type, evaluation plan and sample quantity. We can discuss the proposed powder and the information available for your technical team.
Discuss powder for your trialCommon questions
Does a finer powder always disperse better?
Do not assume it does. Particle size is one input; the material, formulation, mixing and forming conditions also need evaluation. Use a controlled comparison for your process.
Can I judge dispersion from a bottle of powder?
No. The bottle can support an initial material discussion, but dispersion concerns how particles distribute in the processed compound or part.
Does this establish a powder addition rate?
No. The compounder must determine the formulation and evaluate the resulting product. Research formulations are not Bedrock recommendations or guaranteed replacement rates.