Frequently asked questions

Processing technology for resins using the cryogenic energy of liquefied natural gas

Cryogenic and Freezer Grinding using liquefied nitrogen
Predrying using dry air with an ultralow dew point

<About contract grinding>

What kind of materials can be ground?

We believe that almost organic material or resin will be able to be ground as most materials tend to become brittle when cooled at low temperature.

Inadequate:: Thermosetting resins (after curing), inorganic compounds (e.g. ceramics, glass and minerals), fibrous materials (e.g. chemical fibers, carbon fiber, glass fiber), etc.

Effective:: Thermoplastic resins (e.g. super engineering plastics, elastomers and waxes)

How finely can the material be ground?

It can be ground down to an around average particle size of over 10 μm (25 μm pass).
However, the particle size varies greatly depending on the type of grinder and the type of resin.
Also, productivity needs to be considered separately.

Is it possible to remove moisture from (dry) raw materials by cryogenic and freezer grinding?

No, it isn’t. Since moisture contained in raw materials is also frozen, it remains after grinding.

Can Osaka Gas Liquid grind any material?

We have established acceptance criteria and decide whether or not we will accept a material after confirming the SDS of the relevant material.
Please contact us first and submit the SDS.

What specific materials can be ground?

We have extensive experience in grinding and will let you know after investigation.
Examples)　
・ Super engineering plastics: PPS, PES, PEEK, PTFE, etc.
・ Polyolefins: HDPE, UHMWPE, acid-modified polyolefins, etc.
・ Polyesters: PET, PBT, various other polyesters and elastomers, etc.
・ Polyurethanes: Various polyurethanes, elastomers, etc.
・ Others: Various polyamides, etc.

What is the minimum amount you will accept on contract?

We can undertake contract grinding at each stage, from making samples of a few kilograms to mass production scale of several tons.
We will grind your product on contract with the appropriate scale of grinder according to your requirements.

Can you accept only trial grinding?

Yes, we can accept trial grinding alone. We will do our utmost to help with your product development.

Are there any restrictions on raw material size?

Raw materials of approximately 5 mm square are suitable for our grinders.
For larger materials, a coarse grinding process is required, which should be considered separately.

What is your grinding capacity?

We can grind materials up to several tons/day.
However, the grinding volume varies depending on the grinder used, resin type and target particle size.

What is the yield (yield rate) during grinding?

It is usually 90 to 95% or higher.
However, the yield may be lower by classification or higher by an increased quantity processed at one time.

How long does it take to deliver trial ground product?

We will conduct trial grinding after consultation with you and deliver the product approximately one week after completion.
However, we may consult with you during busy times.

Is there any risk of foreign matter contamination?

We strive to prevent foreign matter contamination to the maximum extent possible.
・ We disassemble all the grinder parts and clean them by hand.
・ After cleaning, we perform visual inspection before assembling.
・ Dust collectors are installed in areas where there is a risk of contamination due to scattering.

What are the advantage of contract grinding?

It avoids the risks associated with large capital investment and complicated operations, including work management and high-pressure gas and pollution (dust and noise) control.

Others　

We will conduct investigation and report back to you, so please contact us using the Inquiry Form.

<About contract drying>

What kind of materials can be dried?

Our method mainly targets resin pellets that need to be dried and is especially effective for materials that are highly affected by moisture.
Examples) Polyester, polyamide and polyurethane

What happens if materials do not dry?

① Hydrolysis during thermal fusion or long-term storage causes a decrease in molecular weight, leading to a decline in physical properties.
② Moisture content evaporates during the molding process in which heat is applied, causing wrinkles, pinholes and/or cavities and thereby leading to reduction in strength and optical properties.

How much can the drying process reduce the moisture content?

The moisture content can be reduced from a few percent to less than 100 ppm.

What are the differences from general drying methods?

Since materials are processed in a lower temperature range compared to hot air drying, our method significantly reduces degradation due to heat.
In addition, by agitating materials during processing, our method makes drying more efficient and reduces processing time compared to the tray drying method.
Furthermore, compared to other methods, including the agitation method and the disk indirect heating method, pellets are agitated more mildly in our method, resulting in less damage to the pellets.

Cryogenic and Freezer Grinding using liquefied nitrogen Predrying using dry air with an ultralow dew point