25um Expandable Polymer Microspheres SY818 97%

SY818 25 μm Thermally Expandable Polymer Microspheres

SY818 is a white-powder thermally expandable polymer microsphere developed as a physical blowing agent for polymer processing.

The unexpanded microspheres have an average particle size of approximately 25 μm and a particle size range of 20–35 μm. SY818 starts expanding at 140–150°C and reaches maximum expansion at 200–210°C.

It is suitable for lightweighting, controlled foaming and fine closed-cell structure formation in compatible polymers, coatings, adhesives and elastomers.

SY818 Technical Specifications

How Do SY818 Expandable Microspheres Work?

SY818 microspheres consist of a thermoplastic polymer shell containing an expandable core.

During heating, the shell softens and the internal pressure increases. The microspheres expand into hollow microballoons and form individual closed cells inside the material.

This controlled physical expansion can help increase volume, reduce density and improve foam uniformity.

Key Advantages of SY818

• Average particle size of approximately 25 μm

• Controlled 20–35 μm particle size range

• High solid content above 97%

• Fine and uniform closed-cell structure

• Effective product weight reduction

• Controlled thermal expansion

• Improved surface smoothness

• Reduced risk of large foam cells

• Good dispersion in compatible formulations

• Suitable for medium- and high-temperature processing

• Adjustable density and expansion performance

Lightweight Polymer Foaming

SY818 creates hollow microstructures within the polymer matrix. This can reduce the amount of solid material required for a given product volume.

Potential benefits include:

• Lower material density

• Reduced finished-product weight

• Increased product volume

• Improved cushioning

• Better thermal insulation

• Improved sound and vibration damping

• Reduced raw material consumption

The final result depends on formulation, dosage and processing conditions.

Fine Closed-Cell Structure

Unlike conventional foaming methods that generate freely distributed gas, each expandable microsphere forms an individual hollow cell.

This structure can help reduce:

• Large bubbles

• Uneven cell distribution

• Surface pinholes

• Rough surfaces

• Local density variation

• Irregular product thickness

SY818 is suitable for applications requiring both lightweighting and a controlled surface appearance.

Suitable Polymer Systems

SY818 can be evaluated in compatible materials such as:

• PVC

• EVA

• PE

• PP

• TPE

• TPR

• TPU

• EPDM

• Rubber compounds

• Adhesives

• Sealants

• Printing inks

• Coating systems

Compatibility should be confirmed according to the material viscosity, processing temperature and required product performance.

Main Applications

Thermoplastic Extrusion

SY818 can be evaluated in extrusion processes for:

• Plastic profiles

• Foam sheets

• Tubes and hoses

• Cable materials

• Sealing strips

• Synthetic wood

• Lightweight panels

The fine particle size supports controlled foaming and a uniform surface structure.

Injection-Molded Products

SY818 may help reduce the weight of molded polymer parts while controlling the internal cell structure.

Typical applications include:

• Automotive interior parts

• Plastic housings

• Sealing components

• Gaskets

• Lightweight molded parts

• Functional plastic components

Shoe Soles and Footwear

SY818 can be evaluated in EVA, TPR, TPU and compatible rubber formulations.

Potential benefits include:

• Reduced shoe weight

• Improved cushioning

• Increased softness

• Controlled sole thickness

• Fine foam cells

• Improved surface appearance

Synthetic Leather

In synthetic leather and coated fabrics, SY818 can help create a lightweight foamed layer.

Potential advantages include:

• Increased thickness

• Improved softness

• Better flexibility

• Reduced coating weight

• Improved hand feel

• Smooth surface structure

Foam Printing Inks

SY818 can create raised or three-dimensional effects when activated by heat.

Typical applications include:

• Textile foam printing

• Wallpaper printing

• Decorative graphics

• Raised printing

• Braille printing

• Three-dimensional patterns

Coatings

SY818 can be used as a lightweighting and texture-modifying additive in compatible coating systems.

Potential applications include:

• Textile coatings

• Leather coatings

• Automotive coatings

• Paper coatings

• Industrial coatings

• Decorative coatings

Adhesives and Sealants

SY818 may reduce density and improve compressibility in compatible adhesive and sealant formulations.

Applications may include:

• Automotive sealants

• Construction sealants

• Gap-filling adhesives

• Foam tapes

• Lightweight bonding layers

• Compressible sealing materials

Automotive Components

SY818 can be evaluated in automotive polymer and elastomer products such as:

• Weather strips

• Glass run channels

• Interior trim

• Sealing profiles

• Gaskets

• Sound-damping components

Lightweight Composite Materials

Other potential applications include:

• Lightweight putty

• Artificial stone

• Polymer clay

• Composite panels

• Decorative materials

• Porous ceramics

• Construction products

Recommended Processing Methods

SY818 can be evaluated in:

• Extrusion

• Injection molding

• Compression molding

• Calendering

• Coating

• Printing

• Casting

• Compound mixing

Uniform dispersion before thermal expansion is important for consistent product quality.

Processing Temperature Guidance

SY818 starts expanding at approximately 140–150°C and reaches maximum expansion at approximately 200–210°C.

For stable processing:

• Keep premixing temperatures below the expansion range.

• Match the actual material temperature to the required expansion level.

• Avoid excessive heating above the maximum expansion temperature.

• Control residence time at elevated temperatures.

• Avoid unnecessary high shear after expansion begins.

• Measure the material temperature instead of relying only on machine settings.

• Conduct laboratory and pilot-scale trials before mass production.

Excessive temperature or prolonged heating may damage the expanded polymer shell and reduce the final foaming effect.

Recommended Dosage

The optimum addition level depends on:

• Base polymer

• Target density

• Required expansion ratio

• Product thickness

• Processing temperature

• Residence time

• Mixing efficiency

• Surface requirements

• Mechanical property requirements

A small-scale formulation test is recommended to determine the appropriate dosage.

SY818 vs. Chemical Blowing Agents

SY818 may be evaluated alone or in combination with a compatible chemical blowing agent.

Why Choose SHBC SY818?

• Defined 20–35 μm particle size range

• Approximately 25 μm average particle size

• High solid-content powder

• Controlled expansion temperature

• Suitable for industrial formulation development

• Stable batch supply

• Sample evaluation support

• Custom packaging options

• Bulk production capability

• Technical communication for product selection

Storage and Handling

Store SY818 in its original sealed packaging in a cool, dry and well-ventilated area.

Keep the product away from:

• Direct sunlight

• Heat sources

• Open flames

• High humidity

• Excessive pressure

• Premature expansion temperatures

Avoid unnecessary friction or strong compression during handling. Review the product Safety Data Sheet before use.

Frequently Asked Questions

What is SY818?

SY818 is a thermally expandable polymer microsphere used as a physical blowing agent and lightweight polymer additive.

What is the particle size of SY818?

The average particle size is approximately 25 μm, with a particle size range of 20–35 μm.

What is the solid content?

The solid content is greater than 97%.

What is the appearance?

SY818 is supplied as a white powder.

At what temperature does SY818 start expanding?

The expansion start temperature is approximately 140–150°C.

What is the maximum expansion temperature?

The maximum expansion temperature is approximately 200–210°C.

Can SY818 reduce product weight?

Yes. The microspheres expand into hollow microballoons, which can reduce the density and weight of compatible materials.

What materials can be used with SY818?

SY818 can be evaluated in PVC, EVA, PE, PP, TPE, TPR, TPU, EPDM, rubber, coatings, adhesives and other compatible formulations.

Can SY818 be used for extrusion?

Yes. It can be evaluated in profiles, sheets, hoses, cables, sealing strips and other extrusion applications.

Can SY818 be used for injection molding?

Yes. Temperature, pressure, dosage, residence time and mold conditions should be optimized through testing.

Can it be combined with chemical blowing agents?

Yes. SY818 may be used alone or combined with compatible chemical blowing agents to adjust density and cell structure.

Is testing required before industrial production?

Yes. Laboratory and pilot-scale tests are recommended because the expansion result depends on the formulation, equipment and processing conditions.

Request SY818 Samples

Contact Shanghai SanYu Biotechnology Co., Ltd. for SY818 samples, technical specifications, SDS information and bulk supply.

Please provide:

• Base material

• Final application

• Processing method

• Processing temperature

• Target density

• Required expansion ratio

• Current blowing agent

• Estimated purchase quantity