The use of non-woven fabrics as automotive interior decoration materials is the current international development trend. Because of its low cost, strong adaptability, high strength, and light weight, it is widely used in the automotive industry.
However, many non-woven fabrics for automobiles require water repellent finishing, such as automobile carpets. This kind of carpets are generally molded by molding and consist of three to four layers of different materials. The outer surface layer is made of water- and oil-repellent, flame-retardant, and anti-static carpets, and the roof, door trim, and wall protection of the car , Door and window sealing strips generally have to undergo water and oil repellent finishing. However, the traditional water-repellent nonwovens circulating in the market today are obtained by applying a water-repellent finishing agent in the finishing stage. Although the water-repellent effect has been improved, its stability has been unsatisfactory.
In response to this situation, researchers from the Material Science Department of Lower Rhine University of Technology in Germany proposed the “silicone water-repellent finishing technology.” According to the published data, it can be seen that after the silicone water repellent finishing, a layer of polymethylhydrosiloxane emulsion film will be covered on the surface of the non-woven fabric, and its oxygen atoms point to the surface of the fiber, and the methyl It is oriented and arranged away from the fiber surface. Researchers have found that the proper orientation of the silicone polymer on the fiber surface is a necessary condition for its water repellency. Under normal circumstances, the water repellency will increase with the growth of the carbon chain.
In addition to being condensed with each other into a film, polymethylhydrosiloxane can also form hydrogen bonds with the hydroxyl groups on the surface of the fiber, so that the hydrophobic methyl groups are arranged densely and oriented on the surface of the fiber, thereby obtaining satisfactory water repellency, and Has a certain washable effect. The researchers pointed out that the polymethylhydrosiloxanes * keep emulsions. Therefore, the choice of emulsifier is very important in the water-repellent finishing of silicone. After verification, it is found that the temporary composite cationic emulsifier can effectively convert the polymethylhydrosiloxane into a stable emulsion, and can also be decomposed during the finishing and baking process, which better solves the emulsion stability and water repellency The contradiction between.
The silicone water-repellent finishing technology is still in the laboratory stage, but the key experimental data is relatively complete: the best mixing ratio of polymethylhydrosiloxane and emulsifier is 3:7, and the drying temperature should not be lower than 150℃. , Excellent water repellent effect. It is understood that a German automotive manufacturer has already cooperated with Lower Rhine University for experimental production.
In addition, *recently, Mitsubishi Heavy Industries Co., Ltd. of Japan has developed a high-tech resin with waterproof and breathable function. As long as this liquid material called shape memory polymer is applied to the surface of the fabric, the fabric will not be permeable, but the moisture is still It can show through from the inside out, so it is very suitable for making functional clothing such as raincoats. The waterproof and breathable function of the shape memory polymer is similar to that of human sweat pores, and it is very promising.
As an energy-saving and environmentally-friendly building insulation material, foam insulation material is widely used in the insulation and thermal insulation of roofs and exterior walls. However, if preventive measures are taken improperly, there will be potential safety hazards. You need to be very careful when installing and removing, especially in the event of a disaster, rescuers need to take special protective measures to help others while also protecting their own safety.
Cautions during installation
Foam insulation material has the characteristics of insulation and energy saving, and is widely used in many buildings. Traditional insulation materials, such as glass fiber, have excellent thermal insulation performance through spray foam. Foam insulation is a type of polyurethane, which exhibits different properties under different conditions. For example, when polyurethane molecules expand slowly when exposed to heat, phenolic spray can be cured to shrink it. Spray polyurethane foam (SPF) can be sprayed in places where the panels are difficult to reach, and between the walls of a “sandwich panel” structure. Workers can use a special spray gun to spray foam between the walls or in the drill holes to expand the foam to achieve a sealing effect.
Precautions for using polyurethane foam insulation material in construction
Foam insulation materials tend to be more expensive than other types of insulation materials, which also makes them more costly. Additional investment such as improving the water vapor barrier capacity of the foam or increasing its structural stability does not seem to be worthwhile. In addition, the location of the foam insulation material needs to be considered. It should not be placed in a place directly irradiated by the sun or exposed to a high temperature environment. Most foam materials cannot be exposed to high and strong temperatures for a long time. SPF insulation materials must undergo special treatment before they are used. For example, some materials must be appropriately heated during use.
Installation in an exposed environment will cause the foam insulation material to emit harmful chemicals. Since many foam insulation materials use greenhouse gases as the blowing agent, the thickness level and distribution array must be complied with by law. Foam sprays may also release harmful toxins, which means that workers need to fully protect themselves from the inhalation of harmful gases.
Cautions when removing
In the case of dismantling or alteration, the insulation foam may also cause the spread of toxins. Many foams are toxic. If the building is demolished using explosives or other destructive measures, these toxic substances will spread into the air, causing discomfort for workers and residents living in the surrounding areas, not to mention the impact of rising into the atmosphere force. If the building is a water supply site in a nearby community, the severity of these problems will greatly increase. These toxins can cause discomfort if they come into contact with the skin. If they accidentally come into contact with the eyes, they may cause temporary blindness. Therefore, the foam material needs to be removed carefully at low temperatures to ensure maximum safety.
Rescuers must bring safety equipment when a disaster occurs
In unexpected danger, rescuers need to know how to protect themselves in dangerous foam devices. When a building collapses or catches fire, the smoke released by the burning foam into the air can make people unconscious or blind, so it is necessary to carry safety equipment and breathing apparatus. If there are bubbles on fire, they will not only release toxic smoke but also accelerate the rate of burning. If rescuers know about these possible problems, they can better plan their actions at the rescue site.
China is one of the fastest developing countries in the construction industry. By 2014, it is estimated that China's thermal insulation building materials will account for 29% of the global market. At present, China is the country with the largest demand for thermal insulation materials in the world. The prerequisite for energy-efficient buildings is safety. Without safety, the building loses its meaning. Only by eliminating the use of flammable, flammable, and dangerous thermal insulation materials on building walls can the occurrence of major fire accidents be prevented from the source. Foam thermal insulation materials, as wall thermal insulation materials, should be widely used to prevent fires. . Perhaps in the near future, a new generation of insulating foam materials will surely become the main force in building energy conservation.
The foamed wood-plastic composite material is based on the wood/plastic composite material by adding an appropriate amount of foaming agent, nucleating agent, activator, etc. to reduce the density and improve the impact strength, toughness, fatigue cycle and thermal stability. . details as follows:
1) The purpose of the foaming agent is to reduce the quality of the composite material (reduce the density) and make the application of the composite material more extensive. The blowing agent is heated and decomposed to generate gas, which is incorporated into the composite material and exists in the form of microporous bubbles. Foamed plastic is a foam composed of bubbles. This experiment mainly uses chemical foaming, and the foaming agent used is AC.
2) Nucleating agent is a new functional additive. Nanoparticles can not only act as nucleation points of the blowing agent, but also can refine the polymer grains and increase the toughness of the composite material. The main nucleating agent used in this experiment is ultrafine talc.
3) Activator is an agent that can promote AC foaming agent to foam at a lower temperature.
The most professional exhibition in the domestic wood-plastic composite industry-Shanghai International Wood-plastic Composites Exhibition, will grandly open tomorrow at the Shanghai Exhibition Center.
It is reported that the scale of this exhibition is 3,000 square meters, and dozens of high-quality wood-plastic composite materials suppliers will display the most new and excellent wood-plastic products for domestic garden landscape and architectural designers. At the same time, it will also demonstrate the application trend of wood-plastic composite materials through actual cases at home and abroad.
In addition, a concurrent forum organized by the WPC Special Committee-the Ninth WPC International Summit (Shanghai) Forum, will bring together people and experts from China, Japan, Germany and other ** enterprises , Home, garden landscape, etc. Japan’s Mitsubishi Rayon Company, Germany’s Reifenhausen Company and other foreign ** wood plastic companies will appear at the 2013 Shanghai Wood Plastic Exhibition, sharing ** wood plastic products and application cases on the spot, creating a mutual understanding for domestic designers, Opportunity to communicate with each other.
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