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How to choose unsaturated polyester resin materials
Publisher:Xiangtaihao Chemical  Release Time:2019-12-31 20:22:37  Browse Times: Second

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Unsaturated polyester resin (UPR) has room temperature processability and other excellent properties, and is widely used in various fields of the national economy. It has now become the fastest growing and most demanding resin variety in the field of thermosetting resins. There are many unsaturated polyester resin brands on the market. Because there is no unified naming system, it is difficult to distinguish which type and use of resin from the commercial brand name. The resins of the same brand produced by different manufacturers also have properties. There is a big difference. The selection of unsaturated polyester resin is an important issue. Especially for key national projects, if the materials are selected properly, not only product quality can be ensured, but costs can be effectively reduced, resources can be saved, and waste caused by unnecessary excess quality or engineering accidents caused by insufficient quality can be avoided. The technical properties of unsaturated polyester resins include liquid resin performance indicators such as resin viscosity, gel time, and reactivity. These performance indicators provide users with parameters for different molding processes. The intrinsic properties of unsaturated polyester resin include the rheological properties (molding shrinkage), mechanical properties (stretching, bending, impact, compression, etc.), thermal properties, electrical properties, etc. These indicators are after the resin is crosslinked and cured The properties shown provide parameters for different applications after the resin is cured. Because some application companies do not know much about the properties of resins, they should avoid misunderstandings in resin selection. For the misunderstanding of buying unsaturated polyester resin materials, experts introduced the avoidance of misunderstanding. Specifying the molecular structure type of the required resin For a long time, whether it is a resin supplier or a resin application company, it is customary to classify unsaturated polyester resins according to their molecular structure. Benzene type, bisphenol A type, etc. As mentioned above, in addition to the intrinsic properties of the product (performance after curing), it is not only related to the type of dibasic acid in the formula, but also related to the choice of glycol, the feed ratio (alkyd ratio and double bond ratio), the endpoint acid value, There are many other factors related to the synthetic process. And in the advanced technology abroad, blended resin is widely used as a promising synthetic resin method. This method uses various resins with different molecular structures to mix to achieve the best performance that cannot be achieved by a single resin, maximizes the cost-effectiveness of the resin, and provides a wide choice for downstream users. It cannot be simply classified by the o-benzene or m-benzene type. In the ISO international standard, the various types of UP-R are based on the parameters of the base polymer, possible fillers / reinforcing materials (kind and content), the expected molding method, special properties and characteristics for processing purposes (Process performance) classification, rather than classification based on the molecular structure of the resin. As China's Shenzhen enters the WTO, the classification of unsaturated polyester resins will tend to be scientific, rational, and international in order to achieve international standards. Specify all the properties of the resin. When introducing the properties of unsaturated polyester resins in some materials, it is pointed out that certain physical properties can be achieved after curing, and the scope of these indicators is given. However, the fact is that there are very few resins, and each index or multiple indexes can reach the upper limit of this range at the same time, because these indexes are contradictory. In general, each type of resin has its unique strengths in terms of performance. A scientific attitude is based on its own practical application. It is not advisable to pursue the “high, large, comprehensive” one-sided pursuit of the main performance indicators required by the resin. It must be recognized that there is no perfect "universal material", no matter what kind of resin has certain limitations and has a certain scope of application. Regarding the specified physical properties of the resin without specifying the test method, as described above, the method of preparing the sample when testing the performance of the resin, the length of the heat treatment time of the resin after curing, the level of the processing temperature and other factors directly affect the resin's inherent performance indicators test value. Most domestic unsaturated polyester resin production plants implement the national standard GB / T8237-2005. This standard does not specify the curing method of the sample in the resin test method, but stipulates that the curing is performed at the temperature and time specified by the manufacturer. If the resin manufacturer implements GB / T8237-2005, it must clearly specify which curing method and sample post-treatment method are used. At the same time, the physical properties of products provided by different manufacturers are not horizontally comparable due to the different preparation methods of the samples.

Keyword: Unsaturated   polyester   resin  

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