Warm Global Customers
With China Plastic Machinery
With China Plastic Machinery
Microporous polypropylene, referred to as MPP, refers to a polypropylene (PP) porous foam material with a pore size of less than 100¦Ìm.
Polypropylene microporous foam material, referred to as MPP, refers to a polypropylene porous foam material with a pore size of less than 100 microns (more strictly defined as a pore size of less than 10 microns and a pore density greater than 10 to the 9th power per cubic centimeter). Since Nam P. Suh of MIT first proposed the concept of polymer microporous foaming in the early 1980s, MPP has been a research hotspot in the field of polymer foaming due to its potential broad application prospects.
The molding of MPP requires upgrading general polymer processing equipment (such as injection molding equipment, continuous extrusion molding equipment and compression molding equipment, etc.) so that it can apply supercritical fluid technology. Supercritical carbon dioxide or supercritical nitrigon is introduced into polypropylene material under high temperature and pressure to form a single-phase solution of polypropylene/supercritical fluid, and induce bubble nucleation and growth, and finally form a PP foam material with a cell size in the micrometer scale.
High melt strength polypropylene (PP) is generally required to manufacture MPP. Since general PP is a linear semi-crystalline polymer, the processing window is narrow and it is difficult to obtain a closed cell structure.
Existing foaming materials are either hard and brittle (most structural foams) or soft and tough (most soft foams), and it is difficult to have both rigidity and toughness. Polypropylene microporous foam material has both rigidity and toughness, which makes up for the shortcomings of existing foaming materials.
MPP is prepared using supercritical fluid technology, the foaming process is clean and pollution-free, and the foamed products are safe and environmentally friendly. PP materials do not undergo cross-linking during the foaming process and can be recycled.
PP itself is a safe and non-toxic material and is currently the preferred material for baby bottles and microwave lunch boxes. Clean and hygienic MPP is particularly suitable for fields such as medical devices and food that have high requirements for the hygiene level of packaging materials. It can also be used in fields such as children's puzzles, handicrafts, floor mats and toys that have high requirements for product safety, replacing the commonly used cross-linked PE and EVA foams made from AC foaming agents.
The heat deformation temperature of PP foam materials is much higher than that of PE, PS, and PU foam materials. Therefore, MPP is particularly suitable for high-temperature packaging, high-temperature insulation and other fields.
MPP combines reinforcement, heat insulation and noise reduction, and is also particularly suitable for fields with high requirements for material lightweighting, such as automobiles, rail transportation and ships. The micron-sized pores of MPP give the material the following special features:
(1) Under the same foaming ratio (or apparent density), due to the smaller pore size, the mechanical properties of microporous foam materials lose less. This means that using MPP can save more materials and reduce the weight and volume of products.
(2) Since the pore size can be controlled between 1-100¦Ìm, MPP can be cut into ultra-thin sheets with a thickness of less than 0.1mm, and the surface of the sheet will not be perforated, which can be used in the packaging of microelectronic devices.
(3) Due to the presence of a large number of micron-sized pores on the surface, MPP is suitable as a reflector for the backlight module of a liquid crystal display to improve the diffuse reflectivity.
(4) The micron-sized pores effectively reduce the convection of the gas in the pores, thereby effectively reducing the heat transfer caused by air convection. Therefore, high-ratio microporous foaming materials have a long-term stable low thermal conductivity that depends on the pore structure.
(5) The lightweight and high-strength MPP sheet is suitable for use as a speaker diaphragm.
(6) Also due to its micron-sized pores, MPP has excellent surface protection properties and can be used in packaging fields with high protective requirements such as liquid crystal panels.
PP foam products are mainly divided into two categories: EPP particles and PP foam sheets and plates. EPP is represented by Japan's JSP, and its advantage is that it is suitable for processing into special-shaped components, such as automobile bumper buffer blocks, liquid crystal panel packaging boxes, etc. After several years of research and development, several Chinese units engaged in EPP research and development and production are now able to mass produce or close to mass production.
PP foam sheets are represented by low-ratio (<5 times) PP foam sheets (thickness <5mm) from Japan's Mitsui Chemicals, Furukawa Electric, etc. and high-ratio (maximum 30 times) cross-linked PP foam sheets (thickness <5mm) from Toray and Sekisui Chemical. They are currently used in knife cards, electronic packaging materials, automobile dashboards, etc. The PP foam materials produced by the above-mentioned Japanese companies are not microporous structures.
The supercritical carbon dioxide molded microporous foaming technology proposed by Professor Zhao Ling's research group at East China University of Science and Technology can produce polypropylene microporous foam sheets and plates with controllable pore sizes of 10-100 microns. In particular, the polypropylene microporous foam material produced by this technology can have a maximum foaming ratio of 40 times and a maximum product thickness of 70mm. At present, several Chinese companies have applied this technology and carried out large-scale production. The attached figure shows MPP sheets and plates of different thicknesses and the internal pore structure of the product produced by Zhejiang Xinhengtai New Materials Co., Ltd.
The micron-scale pores give MPP a unique structure and performance, making it have broad application prospects in the fields of precision packaging, optoelectronic technology, etc. In addition, the excellent shock absorption, cushioning, heat insulation and sound absorption properties of clean and environmentally friendly MPP make it expected to become the best substitute for traditional EVA, PU, PS foam materials, EPE and EPP, and can be widely used in packaging, transportation, luggage, sports equipment and other fields.
Lightweight, high-strength, low-ratio MPP can significantly reduce the consumption of raw materials and reduce the weight of products while maintaining the necessary performance of the products. This is undoubtedly of great significance for reducing the consumption of petrochemical resources and protecting the environment, and also means huge market space.
If you are interested in our company and machine, feel free to contact our sales engineer. We will contact you as soon as possible.