The development direction of new products in the field of polyurethane

When everyone is confident that China's polyurethane industry has entered a stage of rapid development, we should pay more attention to the future development direction of polyurethane, where technology accepts the most difficult innovation challenges, and where benefits are maximized. In which areas should our perspective stay more, I hope that after reading the following articles, I can gain something.

1. Polyurethane rigid foam and building energy saving

Polyurethane rigid foam is currently the best thermal insulation product among all wall thermal insulation materials, and it is also the most forward-looking thermal insulation material in the world. The Science and Technology Department of the Ministry of Construction has established a working group for the promotion of polyurethane building energy-saving application, and held the "International Exchange Conference on Polyurethane Wall Energy-saving Application Technology" in Beijing on October 10, 2006. The meeting agreed that polyurethane material is the best thermal insulation material in the world at present, with excellent properties such as light weight, heat preservation, moisture resistance, sound insulation, heat resistance, shock resistance, corrosion resistance, easy bonding with other materials, and no molten droplets when burned. At present, polyurethane rigid foam is mainly used in heating, refrigeration, shipbuilding, petroleum, chemical, automobile, transportation and other industries in my country, and the share used in building wall insulation is less than 10%. About 49% are polyurethane materials. With the further improvement of domestic building energy-saving standards, institutions and enterprises that carry out a series of researches in the field of thermal insulation and energy-saving have gradually increased, and rigid polyurethane products will "bring great plans" in the field of construction.

2. Polyurethane tires

Polyurethane elastomer is a polymer composite material with high hardness of plastic and high elasticity of rubber. Based on the excellent mechanical properties, the application of polyurethane elastomers in tires has been studied since the 1960s. In particular, cast polyurethane elastomer is the most wear-resistant elastomer at present. It has the advantages of coloring, high cutting resistance, vibration absorption, shock absorption, very large load capacity, excellent oil resistance and chemical resistance, and is non-toxic to human body. It can also be completely biodegraded without adding carbon black and aromatic oil, and it is an ideal material for making tire treads. Polyurethane tires are manufactured by casting process, and their structure is very different from the tires currently produced. Full polyurethane pneumatic tire is composed of three parts: carcass, belt layer and tread. Some polyurethane pneumatic tires have two forms: one is that the carcass is cast polyurethane, and the tread is the rubber used to make ordinary tires; the other is that the carcass is a radial carcass, and the tread is polyurethane. Compared with ordinary steel wire radial tires, polyurethane pneumatic tires have the following advantages:

 (1) average 10% lower fuel consumption; 

(2) 51% lower tread wear; 

(3) 30% lighter weight;

 (4) lower rolling resistance 35% % or more;

 (5) The uniformity is better, and there will be no tread peeling.

There are two types of PU tires: full PU wheels (PP type) and rubber tires and PU inner tubes (RP type). Product advantages: good shock absorption, friction resistance, no fear of iron nails, no deflation, no need to repair tires, and save money. However, there are still some problems to be solved in the current research on polyurethane tires, such as improving the traction braking performance of polyurethane tires, improving the hydrolysis resistance, and the multiple injection molding process of truck tires. In the process of developing polyurethane tires, high temperature resistance is the main factor affecting the practical application of polyurethane tires.

3. Waste polyurethane recycling

Environmental protection is another major problem faced by the emerging polyurethane industry. With the increasing use of polyurethane materials in the national economy, the amount of use is increasing, and the recycling and reuse of its waste has also received increasing attention. Waste polyurethane mainly includes corner waste from production plants, mold overflow, scrapped automobiles, polyurethane foam and elastomers in refrigerators, waste shoe soles, waste PU leather, and old spandex clothing. At present, there are three main methods for the recycling of polyurethane: physical method, chemical method, and energy method.

Regarding the recycling of waste polyurethane products, the European Union took the lead in promulgating laws and regulations on the recycling of waste plastics from electrical products. The principle is that whoever produces it should recycle; my country should also speed up the recycling of polyurethane products, especially foam products. The recycling of polyurethane is undoubtedly beneficial to environmental protection and resource utilization, but the main problem is whether recycling waste polyurethane is economical. Due to the large amount of polyurethane and the high price of raw materials recently, its waste recycling market has a promising prospect. However, the recycling methods used in the past are generally not economical and have not been widely promoted. Therefore, an economical and feasible recycling method has been developed. It has become a research hotspot in the industry.

4. Polyurethane imitation wood

Polyurethane wood-like materials are injected into the mold through an injection molding machine, and the polyurethane composite material is injected into the mold after solidification and then taken out for post-coating and other processing. Polyurethane products have the characteristics of low density, light weight, good dimensional stability, and not easy to deform. They can be used as structural support parts of furniture with embedded wooden rods and iron bars. Polyurethane imitation wood material uses the method of modeling to mold various complex structures and engraving patterns, which can be planed, nailed, and sawed, and has the reputation of "synthetic wood". Of course, in addition to good molding performance, polyurethane imitation wood furniture has more advantages than traditional wood furniture in price, and with the shortage of natural wood and the increase in environmental awareness, polyurethane imitation wood furniture is popular in developed regions such as Europe and the United States. increasingly popular. At present, there are relatively few enterprises producing PU imitation wood furniture in China, among which there are even fewer large-scale enterprises. Most of them are concentrated in the coastal areas of East China and South China, and all the products they produce are used for export. Therefore, polyurethane imitation wood furniture is widely used in China. The market has huge room for development. From 2003 to 2004, the domestic manufacturers engaged in the production of polyurethane imitation wood furniture did not export much of their products, but after 2005, the price of raw materials gradually fell, and the overseas orders of these manufacturers gradually increased, and each manufacturer was fully loaded. Construction started, and some even started to expand production. According to rough calculation, in 2005, the usage of imitation wood hard foam reached 20,000 tons. According to the current international situation, the development of PU imitation wood furniture in China will gradually accelerate in the next few years.

5. Spray polyurea elastomer

Spray Polyurea Elastomer (SPUA for short) technology is a foreign technology in the past decade, following the low (non-) pollution coating technology of high solid coatings, water-based coatings, radiation curing coatings, powder coatings, etc., in order to meet the needs of environmental protection. A new solvent-free and pollution-free green construction technology developed and developed is developed on the basis of reaction injection molding (RIM) technology. Its main raw material is amino-terminated polyoxypropylene ether (amino-terminated polyether ). Amino-terminated polyether and liquid amine chain extenders, pigments, fillers and additives form color paste (R component), and the other component is prepared by reacting isocyanate with oligomer diol or triol (A group) Minute). The A component and the R component are sprayed by spraying equipment to obtain the polyurea elastomer. The process is a quick-response spray system, the raw material system does not contain solvent, the curing speed is fast, and the process is simple. SPUA technology has completely broken through the limitations of traditional environmental protection coating technology. In contrast, the product has better wear resistance, aging resistance, corrosion resistance and thermal stability. Therefore, as soon as the technology came out, it developed rapidly.

6. Water-based polyurethane

Waterborne polyurethane dispersion resins (PUDs) have many advantages compared with polymers of other structures, and meet the requirements of environmental protection, mainly in: (1) Disperse in water, no free isocyanate, non-toxic; (2) Good for substrates good adhesion and good physical and mechanical properties, such as abrasion resistance and impact resistance; (3) good compatibility with other water-based polymers such as acrylic; (4) low solvent content, in line with VOC emission requirements, It can even achieve zero VOC; (5) Using water as the medium, it is non-toxic, non-flammable, non-polluting, non-hazardous, less odorous, does not pollute the environment, saves energy, and is suitable for substrates that are easily eroded by organic solvents.

The disadvantages are: slow drying speed, low initial viscosity and poor water resistance.

7. Vegetable oil polyether polyol

At present, the production of existing polyether polyols mainly uses downstream products of petroleum such as propylene oxide and glycerin, which are resource-constrained and costly. In recent years, a few companies at home and abroad have made full use of some low-cost vegetable oils such as soybean oil and palm oil as raw materials to develop a series of vegetable oil polyols to replace conventional polyether polyols. One of the companies in the United States that uses vegetable oils to develop polyurethane polyols. This polyol can reduce production steps, and the genetic modification of vegetable oil can theoretically directly extract industrial products from green plants. Dow was the first to test flexible foamed polyols, with successful laboratory and pilot plant-scale production. Current situation of polyether industry: The production of existing polyether polyols mainly uses downstream products of petroleum such as propylene oxide and glycerin, which are resource-constrained and costly. Expected goal: The use of different renewable natural oils, including linseed oil, rapeseed oil, soybean oil and castor oil, can replace high-cost crude oil and natural gas feedstocks to produce polyether polyols, which can produce vegetable oil polyether polyols. Vegetable oil polyether polyols can be used to produce a variety of soft and rigid foam polyurethane products, mainly used in automobiles, furniture, mattresses and thermal insulation materials.

In the next 10-15 years, vegetable oil-based polyols can replace various component materials extracted from petroleum for the manufacture of polyurethane foams, elastomers, coatings, adhesives and sealants.

8. Non-isocyanate polyurethane

The United States is in a leading position in the production and research and development of non-isocyanate polyurethanes, and has successfully developed non-isocyanate polyurethanes to replace conventional polyurethanes for coatings. Its chemical resistance is 1.5 to 3 times that of conventional polyurethane, while the price is almost the same as conventional polyurethane. Eurotech intends to commercialize this new type of polyurethane for applications in crack-resistant composites, chemical-resistant coatings, and sealants. The plant with an annual output of 500,000 tons was commissioned in Israel in 2001. In 2001, a "Cooperative Technology Development Agreement" was signed for Eurotech's Hybrid Non-Isocyanate Polyurethane (HNIPU). In 2002, a new acrylic product (A-HNIPU) was added to the series of non-isocyanate polyurethane products. A-HNIPU is used in the manufacture of advanced functional coatings and adhesives with high gloss, excellent adhesion, good hardness and chemical resistance. The product will be distributed in the United States and Europe as a new generation of polyurethane products. Non-isocyanate polyurethane makes up for the weak bond structure in conventional polyurethane molecules from the molecular structure, and has excellent chemical resistance, hydrolysis resistance and permeability resistance, and the toxic polyisocyanate is omitted in the preparation process, and the raw materials used are all It is not moisture-sensitive, which brings convenience to the storage and construction of raw materials, and will not cause structural defects in the material due to the generation of air bubbles. In view of the above reasons, non-isocyanate polyurethane has developed rapidly in recent years. It is gradually realizing industrialization in western countries such as Europe and the United States. It is widely used in coatings, elastomers, adhesives and other industries, and has the potential to compete with conventional polyurethanes. However, there is no literature report on the research in this field in my country, let alone industrialization. Therefore, accelerating the research and development of non-isocyanate polyurethane is an important direction for the development of new polymer materials in my country. Non-isocyanate polyurethane has a very broad development prospect and is a new generation of polyurethane system.

9. Decompression and slow rebound sponge

Nowadays, more and more urban white-collar workers are beginning to pay attention to sleep health issues. The mattress is no longer a sleeping device in the traditional sense, but is endowed with more humanized care and high-tech content.

Slow rebound is a new type of material first developed by NASA as a support and protective pad for astronauts during space travel. This high-tech material can automatically adjust the shape of the spacesuit according to the astronaut's body shape and body temperature, thereby reducing the pressure on the human body. With the development of science and technology, the high-tech materials of the past have found their new uses in the civilian home furnishing industry. Compared with ordinary sponge mattresses, slow-rebound mattresses made of aerospace materials have stable chemical and physical properties, anti-mite, anti-fungal, and good air permeability; professional ergonomic design, with adhesion and elasticity With temperature sensitivity, it can provide maximum comfort to the human body and when the pressure is removed, the mattress can spring back to its original position without deformation. Because all people are of different heights, some areas are not accessible at all. The decompression and slow rebound mattress has a unique cushioning memory function. No matter how tall, short, fat or thin, the body can be in close contact with the mattress. When the human body is lying flat, the heavier parts of the body, the back and the buttocks It sinks naturally, and the lighter waist is naturally lifted to keep the spine straight, which is in line with ergonomic principles. No matter where you lie, the mattress can be adjusted to your body shape and is suitable for all people. PressureRelief reduces pressure and pain points to a minimum, improves blood circulation, and keeps the body from numbness after prolonged operation.

10. PU sleepers (Eslon Neo Lumber FFU)

Elson New Wood is a dimensionally uniform synthetic material produced from long fiberglass reinforced at 60 degrees. Over the past 20 years or so, Japanese-made products have become popular in the Asian market as building materials. In the Asian market, the composite material has proven to be useful for a variety of purposes. More specifically, it is used where wood cannot be used, or where it is easily a substitute for wood, whether for technical or economic reasons. The most common uses for this composite are fish ponds, cellars, walkways, earth anchors (usually cement), and track sleepers. For example, the tracks of the Shinkansen, a high-speed train in Japan, are paved with polyurethane sleepers.

11. Nano polyurethane

The so-called "nano-polyurethane" refers to an organic/inorganic nanocomposite material in which inorganic fillers are dispersed in the polyurethane material in nanometer size. In nanocomposites, the size of the dispersed phase is less than 100 nm in at least one dimension. Due to the nano-size effect of dispersibility, large specific surface area and strong interfacial bonding, nano-polyurethane has excellent properties that ordinary polyurethane materials do not have. Therefore, it is a new high-tech new material with broad commercial development and application prospects. Different fillers can be filled into different polyurethane material systems to prepare a lot of polyurethane composite material systems, such as nano-polyurethane coatings. The natural layered silicate clay, which is abundant in my country, is selected as the inorganic filler, and the clay is made by the intercalation composite method. The exfoliation, dispersion and recombination of the lamellae in the polymer matrix with their nanostructural units. Overcoming the three major problems of dispersion, agglomeration and interface difficulty in the composite of ordinary nanoparticles and polymers, the performance of polyurethane-based nanocomposite coatings is better than the physical and mechanical properties of conventional polymer composite coatings of the same composition. Not only that, polyurethane-based nanocomposite coatings also have special properties or functions that the original components do not have, providing new possibilities for the preparation of new high-performance materials.

12. Liquid crystal polyurethane

Polyurethane elastomer is a high-elasticity and high-extensibility high polymer material, in which the urethane is composed of amido and ether groups. From the point of view of chemical structure, it can be inferred that the physical properties of polyurethane are between polyamide and polyester. Therefore, the preparation and characteristic research of liquid crystal polyurethane is very necessary. In recent years, the research on liquid crystal polyurethane in the world has also been active, mainly focusing on the selection of raw materials, the optimization of process routes and the improvement of physical properties. Liquid crystal polyurethane is composed of rigid mediator genes and flexible spacer groups, and is a kind of polyurethane with liquid crystal properties in the melt state.

Ester elastomer. The material has good mechanical, thermal stability, high elasticity, high elongation and good processing properties. The synthesis of liquid crystal polyurethane elastomer is processed by one-step or two-step polymerization. Various processes, extrusion, injection molding, coating can be. The products can be further divided into main chain type liquid crystal polyurethane and side chain type liquid crystal polyurethane. No matter what kind of polyurethane, there are two major problems that need to be solved now. One is to synthesize polyurethane with a high enough relative molecular mass to make it have high strength and high modulus properties.

The development direction of new products in the field of polyurethane
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