WSD Expandable Microspheres (Expancel Type)

‌Brand‌: WSD CHEMICAL
‌Product Name‌: WSD Expansible Thermoplastic Microspheres

Product Overview

WSD Expandable Microspheres are advanced thermoplastic hollow microsphere foaming materials. Each tiny microsphere consists of a tough thermoplastic polymer shell encapsulating a special low-boiling point blowing agent. When heated to the activation temperature, the internal blowing agent vaporizes, rapidly expanding the volume of the microsphere to dozens of times its original size. This product enables precise, controllable foaming without complex equipment, widely recognized across industries for lightweighting, texture modification and density reduction

Technical Specifications

· Ultra-high expansion ratio, significantly reduces product density and achieves remarkable lightweight effect

· Closed-cell structure after expansion, uniform bubble size, no large holes or uneven foaming

· Precise activation temperature control, no premature decomposition or sudden gas release

· No special high-pressure foaming equipment required, easy to integrate into existing production lines

· Excellent solvent resistance and thermal stability, no residue, no odor, no pollution to finished products

· Good dispersibility in coatings, inks, plastics, rubber and adhesives

· Multiple temperature grades available, covering low-temperature to high-temperature processing scenarios

Main Application Fields

‌PVC & Thermoplastic Foaming‌
Used in PVC profiles, sheets, WPC boards and injection molded products to achieve uniform and fine closed-cell foam structure, reduce product weight and improve surface smoothness.

‌Water-Based Printing Inks & Textile Printing‌
Added to water-based inks, wallpaper coatings and textile printing pastes to form three-dimensional raised texture, velvet effect and matte surface, enhancing product added value.

‌Leather & Artificial Leather‌
Applied in leather repair mortar, base coating and top coating of artificial leather to improve filling performance, reduce shrinkage and obtain soft and delicate hand feel.

‌Adhesives & Sealants‌
Added to sealants and adhesives to reduce density, improve dimensional stability, reduce shrinkage and enhance cushioning performance.

‌Explosive Sensitizer‌
Used as high-efficiency sensitizer in industrial explosives to form uniform and controllable pore structure, significantly improving explosion performance and economic benefit.

‌Cultural & Educational Toys & Craft Materials‌
Mixed in air-drying clay, plasticine and craft mud to obtain ultra-light, soft and comfortable hand feel.

‌Coatings & Construction Materials‌
Used in architectural coatings, putty and thermal insulation materials to reduce product density, improve thermal insulation and sound absorption performance.

Recommended Usage

Suggested addition dosage: 0.5–5.0 phr, adjust according to target density and expansion effect requirements

For high-expansion lightweight scenarios, the dosage can be increased to 5–10 phr after small-scale testing

Avoid high-shear mixing at too high temperature in advance, to prevent microspheres from expanding prematurely

It is recommended to add in the later mixing stage at a temperature lower than the expansion starting temperature, and perform heating foaming after uniform dispersion

Packaging & Storage

· Standard packaging: 20kg / 25kg cardboard drum or moisture-proof kraft paper bag

· Store in cool, dry and ventilated indoor warehouse, storage temperature should not exceed 30 °C,Keep away from heat sources, open flames and strong oxidizing substances

· The shelf life under recommended storage conditions is 12 months

· Complete MSDS and safety operation manual are available upon request

Frequently Asked Questions (FAQ)

Q1: What is Expandable Microspheres(expansion agent)?
A: Expandable Microspheres is a thermally expandable foaming additive with a polymer shell that encapsulates low-boiling hydrocarbon liquid. It rapidly expands when heated to a specific temperature, forming a uniform closed-cell foam structure.

Q2: What are its core technical characteristics?
A: It appears as a white free-flowing fine powder, with a typical particle size of 20–50μm, expansion ratio up to 20–100 times, and the minimum residual density of finished foam can be lower than 20 kg/m³.

Q3: What is the typical foaming temperature range of this product?
A: Conventional grades have an initial foaming temperature of 120–140°C and a peak expansion temperature of 165–210°C. You can select the corresponding grade according to the temperature window of your actual processing equipment.

Q4: What main application scenarios is it suitable for?
A: It is widely used in PVC foamed shoe materials, injection micro-foaming parts, SBC foaming, PE/EVA foaming, rubber lightweight products and scenarios that require precise control of foaming effect.

Q5: What are its advantages compared with traditional chemical blowing agents?
A: It does not produce chemical decomposition residues and VOC emissions, the foaming process is stable and easy to control, and it can form a uniform closed-cell structure, effectively avoiding common defects such as large pores and surface scorch.

Q6: What is the recommended addition amount in the formulation?
A: The conventional dosage range is 0.3–1.5 phr, and the specific usage can be adjusted according to the target lightweight ratio, product wall thickness and required surface finish. Even a small addition can achieve a significant lightweight effect.

Q7: What precautions should be taken during mixing and processing?
A: It is recommended to carry out high-speed dispersion below 40°C, avoid high-shear and high-temperature pre-mixing for a long time, so as to prevent the microcapsules from breaking in advance and affecting the final expansion performance.

Q8: What are the storage and transportation requirements for microcapsule blowing agent?
A: It should be sealed and stored in a ventilated environment below 40°C, away from direct sunlight and high-temperature heat sources. Avoid prolonged exposure to high humidity environments to ensure that its expansion performance remains stable during the shelf life.