Foamed Materials EPS, EPU, EPE, EPP, EPVC, EP, ESi, EBB Characteristics of The Process And Application Details

Foamed Materials EPS, EPU, EPE, EPP, EPVC, EP, ESi, EBB Characteristics of the Process and Application Details

Overview of foamed materials

Foamed materials are a special kind of materials, they are introduced into the gas through physical or chemical methods during the manufacturing process, forming a material with a large number of microporous structures. These microporous structures give foamed materials many unique properties, such as lightweight, heat insulation, sound insulation, cushioning, etc., and therefore have a wide range of applications in many fields.

Classification

Foamed materials are mainly divided into the following categories:

1. chemical foaming materials: through the decomposition of gas release by heating, the formation of uniform fine pore compounds in the material.

2. Physical foaming materials: foam is formed by the expansion of compressed gas, the volatilization of liquid or the dissolution of solids.

3. Surfactant: Introducing air under mechanical action to form a large amount of foam.

Common types

- Polyurethane Foam (EPU): Excellent insulation, lightweight and elasticity.

- Polystyrene foam (EPS): lightweight, heat insulation, sound insulation, commonly used in packaging materials.

- Polyethylene Foam (EPE): Soft, flexible, commonly used in cushioning materials.

- Polypropylene foam (EPP): good heat resistance, chemical resistance, suitable for demanding environments.

- Polyvinyl chloride foam (EPVC): good chemical resistance and weather resistance.

- Phenolic Foam (EP): high temperature resistance, commonly used in refractory materials.

- Silicone Foam (ESi): High temperature resistance and good chemical stability.

-Bio-based Foam (EBB): derived from renewable resources, biodegradable and environmentally friendly.

Polystyrene Foam

Polystyrene Foam, also known as Expanded Polystyrene (EPS), is a lightweight, porous polymer material made from polystyrene resin through a physical foaming process. The following is a detailed description of polystyrene foam:

Characteristics

- Lightweight: EPS has a very low density, usually around 1.05g/cm³.

- Thermal insulation: Due to its closed cell structure, EPS has excellent thermal insulation properties.

- Sound insulation: EPS is also effective in isolating noise.

- Impact resistance: EPS absorbs and disperses impact energy and has good impact resistance.

As an economical and practical material, polystyrene foam has a wide range of applications in many fields, but it also needs to pay attention to its environmental impact and safety treatment.

Preparation process

There are two main preparation processes for polystyrene foam: one-step impregnation (one-step process) and two-step impregnation (two-step process).

- One-step method: Styrene monomer, initiator, dispersant, water, blowing agent (e.g., pentane and butane) and other additives are mixed and polymerized in a reactor to form resin particles containing blowing agent. After washing, centrifugal separation and drying, the expandable polystyrene beads are obtained.

- Two-step method: Styrene monomer is first polymerized to form polystyrene beads, and then water, emulsifier, blowing agent and other additives are added for heating and impregnation to obtain the expandable polystyrene beads.

Molding process

There are also two main methods for molding process:

1. One-step extrusion route: EPS particles are directly hot extruded and molded after foaming, which is mainly used for manufacturing plates and films.

2. Molding route: EPS particles are pre-foamed and cooked, then heated and molded in a mold so that the particle surfaces are fused during the expansion process to form a foam part.

Application areas

Polystyrene foam is widely used because of its light weight, heat insulation, sound insulation, moisture-proof, vibration damping and excellent dielectric properties:

- Building wall and roof insulation

- Composite board insulation

- Cold storage, air-conditioning, vehicle and ship heat insulation

- Floor heating

- Decoration carving

- Vibration-proof packaging materials for mechanical equipment, instruments, household electrical appliances, handicrafts and other fragile and valuable products.

- Fast food packaging

Environmental Impact and Recycling

Due to the stability of EPS material, the increase of EPS waste has led to the so-called “white pollution”. Therefore, the recycling of EPS has been emphasized, which mainly includes:

1. Recycling granulation: Reduce the volume of EPS waste by heating densification, cold crushing or cold compression processes, and then re-granulation.

2. as a low-density additives and other materials mixed with the manufacture of new lightweight materials, such as lightweight roof insulation materials, concrete foam insulation boards.

3. dissolve in solvents as paint, adhesive or caulking.

4. using chemical methods to crack the recovery of monomers or the generation of solvent oil.

Polyurethane Foam

Polyurethane Foam (PU Foam) is a polymer material formed by the reaction of isocyanate and polyol under the action of blowing agent. It has a variety of properties, including good thermal insulation, lightweight, elasticity and chemical resistance, so it has a wide range of applications in construction, furniture, automotive, packaging and many other fields.

Components and Manufacturing Process

The main components of polyurethane foam include:

- Isocyanates: common ones are toluene diisocyanate (TDI) and diphenylmethane diisocyanate (MDI).

- Polyols: These can be polyester or polyether based and affect the final properties of the foam.

- Blowing agent: Usually a physical blowing agent or a chemical blowing agent, such as water, is used, which reacts with the isocyanate in the reaction to form carbon dioxide, which forms the foam structure.

- Catalyst: speeds up the reaction.

- Foam stabilizers: help stabilize the foam structure.

- Other additives: including flame retardants, pigments, mold release agents, etc.

The manufacturing process usually includes steps such as mixing, foaming and curing, and can be produced by either continuous or intermittent methods.

Types and Properties

Polyurethane foam can be divided into soft, semi-rigid and rigid foam according to the degree of softness:

- Flexible Foam: Commonly used in furniture, bedding, etc. to provide comfort and flexibility.

- Rigid Foam: Mainly used in building insulation, cold storage equipment, etc., providing good thermal insulation performance.

- Semi-rigid foam: with characteristics between soft and rigid.

According to the production process, polyurethane foam can also be divided into:

- Block Foam: Large foam blocks produced by continuous method and then cut into desired shapes.

- Molded Foam: Directly foamed in the mold, i.e. made into foam products of the desired shape.

Fields of application

Polyurethane foam has a wide range of applications, including:

- Furniture: sofas, mattresses, seats, etc.

- Construction: Walls, roofs and floors as thermal insulation materials.

- Automotive: seats, interior materials, etc.

- Packaging: to protect fragile items.

- Refrigeration equipment: to maintain a constant temperature and prevent leakage.

Environmental impact and recycling

The environmental impact of polyurethane foam is mainly characterized by its difficulty in degradation and the emission of toxic fumes in case of fire. Therefore, it is particularly important to study the recycling technology of polyurethane foam, including physical and chemical methods. The physical method recycles polyurethane foam through bonding and pressure molding, as filler, extrusion molding, etc., while the chemical method breaks down the foam and recycles raw materials through alcoholysis, hydrolysis, alkali decomposition, pyrolysis, and other methods.

Polyethylene Foam

Polyethylene Foam (PE Foam) is a foam material made from polyethylene resin as the main ingredient by adding blowing agents, cross-linking agents and other additives. It is a very important cushioning material with many significant features and a wide range of

Characteristics

- Low density: the density of polyethylene foam can be very low, down to 0.01g/cm³.

- Good cushioning: It has a very good impact absorption capacity due to its porous structure.

- Heat resistance: able to maintain stable performance at higher temperatures.

- Low water absorption: good chemical stability, not easy to absorb water, good resistance to most chemical corrosion.

- Mechanical properties: tough, flexible and friction resistant.

- Processing properties: easy to mold and process, cheaper.

Application field

Polyethylene foam has a wide range of applications, including but not limited to:

- Packaging materials: used as buffer packaging for precision instruments and meters, household appliances, fragile products.

- Construction industry: as heat insulation and sound insulation materials.

- Agriculture: used as thermal insulation material for nursery, vegetables, melons and fruits.

- Insulation containers: used for insulation of frozen and hot food.

Production process

The production process of polyethylene foam usually includes the following steps:

1. Mixing: Mix the raw materials such as polyethylene resin, foaming agent and cross-linking agent evenly.

2. foaming: the blowing agent is decomposed by heating or other means to produce gas and form a foam structure.

3. cross-linking: to make the polyethylene molecules form a reticulated structure among themselves by chemical or physical methods to improve the stability and performance of the foam.

4. molding: processing the foam material into the desired shape and size.

5. Post-processing: Including steps such as cooling, cutting and packaging.

Types of products

Polyethylene foam can be categorized into cross-linked and non-cross-linked types:

- Cross-linked polyethylene foam: has better mechanical properties and thermal stability, and is divided into two processes: radiation cross-linking and chemical cross-linking.

- Non-cross-linked polyethylene foam: has better flexibility and elasticity, but relatively low mechanical properties.

Technical properties

The main technical properties of polyethylene foam include:

- Density: varies according to the foaming multiples, usually in the range of 26 to 53 kg/m³.

- Thermal conductivity: low, usually around 0.037 W/m-K, showing good thermal insulation properties.

- Moisture permeability: less than 4.2×10-¹¹ ng/(m-s-Pa), almost impermeable to water vapor.

- Water absorption: very low, usually no more than 4%.

- Operating temperature range: wide, from -100°C to 90°C.

- Flammability: usually self-extinguishing, self-extinguishing within 2 seconds from fire.

Polypropylene Foam

Polypropylene Foam (PP Foam) is a kind of foam material with polypropylene resin as the main ingredient, which is made by adding blowing agent and other additives through a specific foaming process. It combines the excellent characteristics of polypropylene with the lightweight, heat-insulating and sound-absorbing properties of foam, making it a high-performance material with a wide range of applications.

Characteristics

- Lightweight: Polypropylene foam has a low density, which can significantly reduce the weight of products.

- Thermal insulation: Due to its porous structure, polypropylene foam has excellent thermal insulation and heat preservation properties.

- Sound absorption: The microcellular structure of polypropylene foam gives it good sound absorption properties, which makes it suitable for sound insulation materials.

- Chemical resistance: Polypropylene material itself has good chemical resistance, so the foam also has this characteristic.

- Heat resistance: Polypropylene foam can withstand higher temperatures and has good thermal stability.

- Environmental protection: Polypropylene foam can be recycled and does not produce toxic substances when burned.

Applications

- Automotive industry: Used in the manufacture of bumpers, instrument panels, door panels and other components to provide energy absorption and shock absorption protection.

- Packaging materials: used for shockproof packaging of fragile goods and precision instruments.

- Construction industry: used as heat insulation and sound insulation materials to improve the energy-saving effect of buildings.

- Sports equipment: Used in the manufacture of buoyancy aids, protective pads, etc.

- Medical field: It can be used in the packaging of medical devices due to its non-toxic and clean characteristics.

Production process

The production process of polypropylene foam mainly includes physical foaming and chemical foaming:

- Physical foaming: The foam structure is formed by injecting a physical blowing agent (e.g. carbon dioxide or nitrogen) into the polypropylene melt and then controlling the pressure and temperature so that the blowing agent decomposes to produce gas.

- Chemical foaming: chemical blowing agents, such as azo compounds, are used to form the foam by decomposing and producing gases during the heating process.

Technical Difficulties

- Melt strength: the viscosity of polypropylene drops sharply in the molten state, resulting in easy rupture and merging of the foam pores during foaming, affecting the uniformity of the foam structure.

- Temperature control: Temperature control during foaming is critical to product quality, too high or too low a temperature will affect the performance of the foam.

Research progress

Currently, research on polypropylene foams focuses on improving their foaming efficiency, improving foam structure, and enhancing mechanical properties. For example, the use of High Melt Strength Polypropylene (HMSPP) can improve the stability of the foamed product's blisters and reduce the product's density. In addition, the application of supercritical fluid technology also shows great potential in the preparation of microcellular foamed polypropylene materials.

Polyvinyl Chloride Foam (PVC Foam)

Polyvinyl Chloride Foam (PVC Foam) is a kind of foam material made from polyvinyl chloride resin as the base material by adding blowing agent and other additives through physical or chemical foaming process. It has good physical properties and chemical stability, and is widely used in construction, decoration, packaging, advertising production and other fields.

Characteristics

- Lightweight: PVC foam has a low density, lightweight and easy to handle and construction.

- Thermal insulation: The closed cell structure provides good thermal insulation and heat preservation.

- Sound insulation: The porous structure helps to absorb sound and provide sound insulation.

- Chemical Resistance: Resistant to most chemicals, not easy to corrode.

- Weather resistance: able to adapt to different climatic conditions, resistant to ultraviolet radiation.

- Fire resistance: PVC foam has a certain flame retardant effect, in line with fire safety requirements.

- Waterproof: The closed cell structure makes it waterproof and suitable for use in humid environments.

Application Fields

- Construction industry: used as roof insulation, wall insulation materials, to improve the energy-saving effect of buildings.

- Decoration industry: used for interior decoration, billboards, display racks, etc., with good aesthetics and practicality.

- Packaging industry: used as shockproof buffer material to protect fragile items.

- Advertising production: used for making advertising letters, signboards, etc., with good visual effect.

Production process

The production process of PVC foam mainly includes physical foaming and chemical foaming:

- Physical foaming: By injecting a physical blowing agent (such as carbon dioxide or nitrogen) into the PVC melt, the pressure and temperature are controlled so that the blowing agent decomposes and produces gas to form a foam structure.

- Chemical foaming: chemical blowing agent is used, which decomposes and generates gases during the heating process to form foam.

Technical difficulties

- Foaming uniformity: to ensure that the bubble structure of PVC foam is uniform, to avoid local density is too high or too low.

- Melt strength: Maintain sufficient melt strength in the foaming process to prevent the bubble holes from rupturing.

Research progress

Currently, the research of PVC foam is mainly focused on improving foaming efficiency, improving foam structure and enhancing mechanical properties. For example, microcellular foaming using supercritical fluid technology allows the preparation of PVC foams with finer pores.

Phenolic Foam

Phenolic Foam is a rigid, closed-cell foam made from thermosetting phenolic resin by foaming under specific conditions with a blowing agent. It is known for its excellent fireproofing, heat preservation and thermal insulation properties, and is widely used in many

Characteristics

- Flame retardant: Phenolic foam has excellent flame retardant properties under the action of flame with carbonization, no dripping, no curling and no melting phenomenon.

- Low smoke, non-toxic: low smoke density when burning, almost no toxic gases.

- High temperature stability: it can be used in the temperature range of -200℃ to 200℃, and the long-term use temperature is high.

- Good thermal insulation: closed cell structure provides good thermal insulation, low thermal conductivity.

- Dimensional stability: with benzene ring structure, small rate of dimensional change, no shrinkage or embrittlement in long-term use.

- Chemical resistance: resistant to most inorganic acids, organic acids and organic solvents.

- Environmentally friendly: Freon is not used as blowing agent in the production process, and it is non-toxic and odorless when decomposed.

Application Fields

- Construction industry: used as exterior wall insulation, roof insulation, fireproof isolation belt, etc.

- Aviation, ships: due to its lightweight and fireproof characteristics, it is suitable for internal heat insulation and structural materials.

- Petrochemical industry: used for pipe and equipment insulation, reduce heat loss and improve energy efficiency.

- Electrical Appliances, Instrumentation: used as insulating and thermal insulation material to protect equipment from overheating.

Production process

The production of phenolic foam mainly includes the following steps:

1. Synthesize phenolic resin: condensation reaction of phenol and formaldehyde under the action of acidic or alkaline catalyst.

2. Adding foaming agent and other additives: add appropriate amount of foaming agent, curing agent, flame retardant, etc. according to the required performance.

3. Mixing and foaming: mixing evenly under specific conditions, so that the blowing agent decomposes and produces gas to form a foam structure.

4. Curing and molding: curing under certain temperature and pressure to form the final foam material.

Technical Difficulties

The main technical difficulties of phenolic foams are their high brittleness and high open-cell ratio, which limit their use in certain applications. In order to improve its toughness and performance, researchers have modified it through chemical and physical methods, such as adding reinforcing materials such as nitrile rubber and glass fiber, or improving its performance through surface treatment and composite technology.

Silicone Foam

Silicone Foam is a high-performance foam material made from silicone rubber as a base material by physical or chemical foaming methods. The following is a detailed description of Silicone Foam:

Composition and Characteristics

Silicone Foam is composed of silicone rubber and has the following properties:

- High Temperature Resistance: Wide range of temperature resistance, from -100℃ to 300℃, and can even withstand instantaneous higher temperatures.

- Chemical resistance: good resistance to most chemicals.

- Climate aging resistance: good weather resistance in outdoor environment.

- Electrical insulation: excellent electrical insulation properties.

- Physiological inertness: no irritation to human body, commonly used in medical field.

- High elasticity and flexibility: even at low temperatures, it can maintain flexibility.

- Flame retardant: self-extinguishing properties, suitable for applications requiring fire protection.

Production process

The production process of silicone foam includes:

- Physical Foaming: Gas is introduced into the silicone raw material through mechanical agitation to form foam.

- Chemical foaming: chemical blowing agent is added to produce gas to form foam in the reaction process.

- Curing at high temperature: The foam structure is cured and molded at high temperature.

Application areas

Silicone foam has a wide range of applications, including:

- Aerospace: Used as high temperature insulation and sealing materials.

- Automotive: used as sealing gaskets, cushioning materials and cable insulation.

- Medical field: for medical devices and equipment due to its physiological inertness.

- Construction industry: as thermal and acoustic insulation material.

- Electronic industry: used as insulation and protection material for electronic equipment.

- Daily necessities: such as shoe insoles, cushioning materials for sports equipment, etc.

Technical Parameters

The properties of silicone foam can be described by different technical parameters, for example:

- Hardness: usually in the range of 10-70 Shore A.

- Density: The density of the foam can be adjusted as required.

- Compression Deformation: The rate of compression deformation of the foam under a certain pressure.

- Tear strength: A measure of the foam's ability to resist tearing.

Environmentally Friendly

Silicone foam is an environmentally friendly material with no release of harmful substances and meets many environmental standards.

Bio-based Foam

Bio-based Foam is a new type of environmentally friendly material that is derived from renewable resources, such as plants, crop residues or microbial fermentation products, and is biodegradable or compostable. The following is a detailed introduction of Bio-based Foam:

Composition and Characteristics

Bio-based foams are mainly derived from biomass materials such as:

- Plant-based materials: e.g. corn starch, sugar cane, wood pulp, etc.

- Microbial fermentation products: e.g. polylactic acid (PLA) and polyhydroxy fatty acid esters (PHA).

- Biopolymers: e.g. chitosan, proteins, etc.

These materials have the following properties:

- Renewable: derived from plants or microorganisms that grow sustainably.

- Biodegradability: can be broken down by microorganisms in the natural environment.

- Environmentally friendly: low life cycle carbon footprint.

Production process

Production processes for bio-based foams typically include:

- Chemical synthesis: Synthesis of bio-based polymers through polymerization reactions.

- Physical Processing: Foams are prepared using physical methods such as extrusion, molding and foaming.

- Biofermentation: Production of biopolymers through microbial fermentation.

Areas of application

Bio-based foams are used in a wide range of applications, including:

- Packaging: Replacement of traditional plastic foams for cushioning and protection of goods.

- Building industry: as thermal and acoustic insulation.

- Automotive industry: for lightweighting and interior materials.

- Textiles: as a warming material or filler.

Technological advances

- Synthesis of bio-based polymers: Researchers are developing new bio-based monomers and polymerization methods to improve material properties and reduce costs.

- Foaming technology: By improving the foaming process, the pore size and density of foams can be controlled to meet the needs of different applications.

Environmental impact and sustainability

Bio-based foams have a low environmental impact because they are biodegradable or compostable at the end of their life cycle, reducing plastic waste and microplastic pollution. In addition, the use of renewable resources reduces dependence on fossil fuels and helps reduce greenhouse gas emissions.