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[Polyurethane foaming agent] What you have to know

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[Polyurethane foaming agent] What you have to know

Polyurethane foaming agent

Polyurethane foaming agent is the product of cross combination of aerosol technology and polyurethane foam technology.There are two kinds of spongy states on the tube type and the gun type.Styrofoam is used as a foaming agent in the production of microcellular foams. It can generally be divided into two types: physical type and chemical type. This is based on whether the production of the gas is a physical process (Volatilization or sublimation) or a chemical process(Destruction of chemical structure or other chemical reactions)

 

English name

PU Foam

 

Technology

Aerosol technology and polyurethane foam technology

 

Types

Tube type and gun type

 

Introduction

Polyurethane foaming agent full name one-component polyurethane foam sealant. Other names: foaming agent, styrofoam, PU sealant. English PU FOAM is the product of cross combination of aerosol technology and polyurethane foam technology. It is a special polyurethane product in which components such as polyurethane prepolymer, blowing agent, and catalyst are filled in a pressure-resistant aerosol can. When the material is sprayed from the aerosol tank, the foam-like polyurethane material will rapidly expand and will solidify and react with the air or the moisture in the substrate to form a foam.Wide range of applications. It has the advantages of front foaming, high expansion, small shrinkage, etc.And the foam has good strength and high adhesion. The cured foam has various effects such as caulking, bonding, sealing, heat insulation, sound absorption, etc.It is an environmentally friendly, energy-saving and easy-to-use building material. It can be used for sealing and plugging, filling gaps, fixing and bonding, heat preservation and sound insulation, and is especially suitable for sealing and waterproofing between plastic steel or aluminum alloy doors and windows and walls.

 

Performance description

Generally, the surface drying time is about 10 minutes (under room temperature 20°C).The total dry time varies with the ambient temperature and humidity. Under normal circumstances, the total dry time in summer is about 4-6 hours, and it takes 24 hours or more to dry at around zero in winter.Under normal conditions of use (and with a covering layer on the surface), it is estimated that its service life will not be less than ten years. The cured foam maintains good elasticity and adhesion in the temperature range of -10℃~80℃. The cured foam has the functions of caulking, bonding, sealing, etc.In addition, flame-retardant polyurethane foaming agent can reach B and C grade flame retardant.

 

Disadvantage

  • Polyurethane foam caulking agent, the temperature is high, it will flow, and the stability is poor. Not as stable as polyurethane rigid foam.
  • Polyurethane foam sealant, the foaming speed is too slow, large area construction cannot be carried out, the flatness cannot be controlled, and the foam quality is too poor.
  • Polyurethane foam sealant, expensive

 

Application

  • Door and window installation: Sealing, fixing and bonding between doors and windows and walls.

2. Advertising model:Model, sand table production, exhibition board repair

3. Soundproofing: Filling up the gaps in the decoration of speech rooms and broadcasting rooms, which can play a sound insulation and silencing effect.

4. Gardening:Flower arrangement, gardening and landscaping, light and beautiful

5. Daily maintenance: Repair of cavities, gaps, wall tiles, floor tiles, and floors

6. Waterproof plugging: Repair and plug leaks in water pipes, sewers, etc.

7. Packing and shipping: It can conveniently wrap valuable and fragile commodities, saving time and speed, shockproof and pressure resistant

 

Instructions

  • Before construction, oil stains and floating dust on the construction surface should be removed, and a small amount of water should be sprayed on the construction surface.
  • Before use, shake the polyurethane foaming agent tank for at least 60 seconds to ensure that the contents of the tank are uniform.
  • If a gun-type polyurethane foaming agent is used, turn the tank upside down to connect with the spray gun thread, turn on the flow valve, and adjust the flow before spraying. If tube type polyurethane foaming agent is used, screw the plastic nozzle on the valve thread, align the plastic pipe with the gap, and press the nozzle to spray.
  • Pay attention to the travel speed when spraying,usually the injection volume can be half of the required filling volume. Fill vertical gaps from bottom to top.
  • When filling gaps such as ceilings, the uncured foam may fall due to gravity. It is recommended to provide proper support immediately after filling, and then withdraw the support after the foam is cured and bonded to the wall of the gap.
  • The foam will be debonded in about 10 minutes, and it can be cut after 60 minutes.
  • Use a knife to cut off the excess foam, and then coat the surface with cement mortar, paint or silica gel.
  • Weigh the foaming agent according to the technical requirements, add 80 times of clear water to dilute to make a foaming liquid; then use a foaming machine to foam the foaming liquid, and then add the foam to the uniformly mixed magnesite cement slurry according to the predetermined amount Stir evenly, and finally send the foamed magnesite slurry to the forming machine or mold for forming.

 

Construction Notes:

The normal use temperature of polyurethane foaming agent tank is +5~+40℃, Best use temperature +18~+25℃. In the case of low temperature, it is recommended to place this product at a constant temperature of +25~+30℃ for 30 minutes before using it to ensure its best performance.The temperature resistance range of the cured foam is -35℃~+80℃.

 

Polyurethane foaming agent is a moisture-curing foam. It should be sprayed on the wet surface when used. The higher the humidity, the faster the curing.Uncured foam can be cleaned up with a cleaning agent, while the cured foam should be removed by mechanical methods (sanding or cutting). The cured foam will turn yellow after being irradiated by ultraviolet light. It is recommended to coat the cured foam surface with other materials (cement mortar, paint, etc.). After using the spray gun, please clean it with a special cleaning agent immediately.

 

When replacing the tank,shake the new tank well (shaking at least 20 times), remove the empty tank, and quickly replace the new tank to prevent the spray gun connection port from solidifying.

 

The flow control valve and trigger of the spray gun can control the size of the foam flow. When the injection stops, immediately close the flow valve in a clockwise direction.

 

Safety Precautions

 

Uncured foam is sticky to skin and clothing. Do not touch your skin and clothing during use. Polyurethane foaming agent tank have a pressure of 5-6kg/cm2 (25℃) , and the temperature should not exceed 50℃ during storage and transportation to prevent explosion of the tank.

 

Polyurethane foaming agent tanks should be protected from direct sunlight and children are strictly prohibited. Empty tanks after use, especially partially used polyurethane foaming tanks that have not been used up, should not be littered. It is forbidden to burn or puncture empty tanks.

 

Keep away from open flames and do not contact with flammable and explosive materials.

 

The construction site should be well ventilated, and construction workers should wear work gloves, overalls and goggles during construction, and do not smoke.

 

In case the foam touches the eyes, please rinse with water before going to the hospital for medical treatment; if it touches the skin, rinse with water and soap

 

Foaming process

 

  • Prepolymer method

The pre-polymer method foaming process is to make (white material) and (black material) into pre-polymer first, and then add water, catalyst, surfactant, other additives to the pre-polymer, and mix under high-speed stirring. Soak, after curing, it can be cured at a certain temperature

 

  • Semi-prepolymer method

The foaming process of the semi-prepolymer method is to make a part of polyether polyol (white material) and diisocyanate (black material) into a prepolymer, and then combine another part of polyether or polyester polyol with diisocyanate, water , Catalysts, surfactants, other additives, etc. are added and mixed under high-speed stirring for foaming.

 

  • One-step foaming process

Add polyether or polyester polyol (white material) and polyisocyanate (black material), water, catalyst, surfactant, blowing agent, other additives and other raw materials in one step, and mix under high-speed stirring and then foam.

 

One-step foaming process is a commonly used process. There is also the manual foaming method, which is the easiest method. After all the raw materials are accurately weighed, they are placed in a container, and then these raw materials are mixed uniformly and injected into the mold or the space that needs to be filled with foam. Note: When weighing, the polyisocyanate (black material) must be weighed in last.

 

Rigid polyurethane foam is generally foamed at room temperature, and the molding process is relatively simple. According to the degree of construction mechanization, it can be divided into manual foaming and mechanical foaming. According to the pressure during foaming, it can be divided into high-pressure foaming and low-pressure foaming. According to the molding method, it can be divided into pouring foaming and spraying foaming.

 

 

 

Policy

 

Polyurethane foaming agent was listed by the Ministry of Construction as a product to be promoted and applied during the "Eleventh Five-Year Plan" period.

 

Market expectation

Since 2000 products were promoted and applied in China, the market demand has expanded rapidly. In 2009, the annual consumption of the national construction market has exceeded 80 million cans. With the improvement of building quality requirements and the promotion of energy-saving buildings, such products The amount of glutathione will increase steadily in the future.

 

Domestically, the formulation and production technology of this type of product have been fully mastered, fluorine-free foaming agents that do not destroy the ozone layer are generally used, and products with pre-foaming (1) have been developed. Except that some manufacturers still use imported valve parts, other supporting raw materials have been made domestically.

 

Instruction manual

(1)The so-called pre-foaming means that 80% of the polyurethane foaming agent has been foamed after spraying, and the subsequent foaming is very small.

 

This allows workers to grasp the strength of their hands when using the foaming gun, which is simple and convenient and does not waste glue. After the foam is sprayed, the glue gradually becomes thicker than when it is shot out.

 

In this way, it is difficult for workers to grasp the force of pulling the trigger on their hands, and it is easy to waste glue, at least 1/3 of the waste. In addition, the post-expanded glue is easy to squeeze the doors and windows after curing, such as the ordinary glue in the market factory.

Pub Time : 2021-08-19 11:21:11 >> News list
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