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The use of non-woven fabrics as automotive interior trim materials is a current international development trend. Because of its low cost, high adaptability, high strength, and light weight, it is widely used in the automotive industry.
However, many automotive nonwovens require water repellent finishing, such as automotive carpets. This type of carpet is generally molded by molding and consists of three to four layers of different materials. The outermost surface layer is made of water-repellent, oil-repellent, flame-retardant, and antistatic treated carpets. The roof, door trim, and guardrail in the car Seals for windows and doors generally have to undergo water and oil repellent finishing. However, the conventional water-repellent non-woven fabrics circulated on the market today are obtained by applying a water-repellent finishing agent in the finishing stage. Although the water repellent effect has been improved, the stability of the water-repellent non-woven fabric has been unsatisfactory.
In this case, researchers from the material speciality of the Technical University of Lower Rhine in Germany proposed the “silicone water repellent finishing technologyâ€. According to the published data, it can be seen that after the silicone water-repellent finishing, the surface of the non-woven fabric is covered with a polymethylsiloxane-based emulsion-like film whose oxygen atoms are directed to the fiber surface, and the methyl group It is oriented away from the surface of the fiber. The researchers found that the proper orientation of silicone polymers on the fiber surface is a necessary condition for water repellency. In general, water repellency increases as the carbon chain grows.
In addition to converging to each other, the polymethyl siloxane can also form hydrogen bonds with hydroxyl groups on the surface of the fiber, so that the hydrophobic methyl groups are densely oriented on the surface of the fiber, so that satisfactory water repellent properties are obtained, and Has a certain wash effect. The researchers pointed out that polymethyl siloxane is best kept in emulsion. Therefore, the choice of emulsifier is critical in the silicone water repellent finishing process. It has been found through verification that the temporary complex cationic emulsifier can efficiently siloxylate the polymethylsiloxane into a stable emulsion, and can also be decomposed during the finishing baking process, so that the stability and water repellency of the emulsion are better solved. The contradiction between.
Silicone water repellent finishing technology is still in the laboratory stage, but the key experimental data has been relatively perfect: the optimum mixing ratio of polymethyl siloxane and emulsifier is 3:7, and the drying temperature should not be lower than 150 °C. , The best water repellent effect. It is understood that a German car production company has cooperated with the University of Lower Rhine for experimental production.
In addition, recently, Mitsubishi Heavy Industries of Japan has developed a high-tech resin with a waterproof and air-permeable function. As long as the liquid material, which is called a shape memory polymer, is applied to the surface of the fabric, the fabric will not be permeable, but moisture can still be obtained. From the inside out, it is very suitable for functional clothing such as raincoats. The waterproof, air-permeable function of the shape memory polymer is similar to that of human sweat pores, and has a promising future.
As an energy-saving and environmental-friendly building insulation material, foam insulation materials are widely used in insulation and heat insulation projects for roofs and exterior walls. However, if preventive measures are taken improperly, there will be potential safety hazards. Care must be taken when installing and removing, especially in the event of a disaster, rescue workers need special protection measures to protect others while helping others.
Precautions during installation
Foam insulation material has the characteristics of insulation, energy saving, and is widely used in many buildings. Traditional insulating materials, such as glass fiber, are also superior in thermal insulation performance by spraying foam. Foam insulation is a type of polyurethane that exhibits different properties under different conditions. For example, when a polyurethane molecule slowly expands as it heats, the phenolic spray can shrink by curing. Sprayed Polyurethane Foam (SPF) can be sprayed on a hard-to-reach place, similar to a "sandwich" structure wall. Workers can use a special spray gun to spray foam between walls or drill holes to expand the foam to seal.
Polyurethane Foam Insulation Used in Construction Considerations
Foam insulation is often more expensive than other types of insulation, which also makes it more expensive. It seems that the additional investment, such as increasing the water vapor barrier capability of the foam or increasing its structural stability, is not worth it. In addition, the location of the foam insulation material needs to be considered. It should not be placed in direct sunlight or exposed to high temperatures. Most foam materials cannot be exposed to high temperatures and intense temperatures for long periods of time. SPF insulation material must be specially treated prior to use. For example, certain materials must be properly heated during use.
Installation in an exposed environment can cause foam insulation to emit harmful chemicals. Since many foam insulation materials use greenhouse gases as blowing agents, laws must be followed to specify thickness levels and distribution arrays. Foam sprays can also release harmful toxins, which means that workers need to fully protect themselves from harmful gases.
Precautions when removing
Thermal insulation foams may also cause the spread of toxins when dismantled or modified. Many foams are toxic. If buildings are dismantled with explosives or other destructive measures, these toxic substances will spread into the air, causing discomfort to workers and residents living in the surrounding areas, not to mention the effects of rising into the atmosphere. force. If the buildings are water supply sites in nearby communities, the severity of these problems will increase significantly. These toxins cause contact with the skin and cause discomfort. If you accidentally come in contact with your eyes, it may cause temporary blindness. Therefore, foams need to be carefully removed at low temperatures to ensure maximum safety.
Rescue workers must carry safety equipment in case of disaster
In case of unexpected danger, rescue workers 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 cause people to lose consciousness or blindness, so it is necessary to carry safety equipment and breathing apparatus. If bubbles ignite, they will not only release toxic fumes but also accelerate the rate of burning. If rescue workers are aware of these possible problems, they can better plan their actions at the rescue site.
China is one of the fastest growing countries in the construction industry in the world. By 2014, China's thermal insulation building materials will account for 29% of the global market. At present, China is the country with the most demand for insulation materials in the world. The energy-saving building first of all has its premise of safety. Without safety, the building loses its significance. Only when the use of flammable, flammable, and dangerous insulation materials on the building walls is eliminated, major fire accidents can be suppressed at the source. Foam insulation materials are used as wall insulation materials and should be widely used while preventing fires from occurring. . Perhaps in the near future, a new generation of insulating foam insulation will certainly become the main force of building energy conservation.
Foamed wood-plastic composites are based on wood/plastic composites with appropriate amounts of foaming agents, nucleating agents, activators, etc. to reduce the density, improve the impact strength, toughness, fatigue cycle, and thermal stability. . details as follows:
1) The purpose of the foaming agent is to reduce the mass of the composite material (reducing the density), making the application of the composite material more extensive. The foaming agent is decomposed by heating to generate gas, which is incorporated into the composite material and exists in the form of microporous bubbles. Foamed plastic is a bubble composed of bubbles. This experiment mainly uses chemical foaming, and the foaming agent used is AC.
2) Nucleating agent is a new functional additive. The nanoparticles not only act as nucleation sites for the blowing agent, but also can refine the high polymer grains and increase the toughness of the composite. The nucleating agent used in this experiment is ultra-fine talcum powder.
3) Activator is a reagent that promotes foaming of AC blowing agents at lower temperatures.
The leading professional exhibition of wood-plastic composite materials industry in China, Shanghai International Wood-plastic Composite Exhibition, will be opened in Shanghai Exhibition Center tomorrow.
It is reported that the scale of this exhibition is 3,000 square meters. Dozens of high-quality wood-plastic composite suppliers will display the latest and best 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 case demonstrations at home and abroad.
In addition, the Ninth Forum of Wood-plastics International Summit (Shanghai), organized by the wood-plastic special committee, will bring together top-level business people and experts from China, Japan and Germany to discuss the construction of wood-plastic composite materials. Applications such as home and garden landscapes. Leading wood-plastic companies from Japan, such as Mitsubishi Rayon Co., Ltd. and Reifenhausen of Germany, will appear at the 2013 Shanghai WPC Exhibition, sharing top-level wood-plastic products and application cases, creating a mutual understanding and communication with domestic designers. Opportunity.
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