Share: Solution of Epoxy Resin Crystallization

Epoxy resin crystallization In the autumn, the temperature gradually lower, epoxy floor materials often encounter without curing agent on the hardening or produce particles This is basically due to the crystallization of the epoxy resin. Conditions for easy crystallization 1. When the epoxy resin is located at 10 ℃, the crystallization speed is the fastest. 2. The lower the chlorine content of the resin, the narrower the molecular weight distribution and the higher the purity, the easier it is to crystallize. Some diluents are particularly easy to crystallize epoxy resin, such as BGE. There are some chemicals that can induce the crystallization of epoxy resin, such as BPA. Dust may also become the crystal nucleus of epoxy resin crystallization, inducing crystallization. 6, the filler may also accelerate the crystallization of epoxy resin. The above is a variety of easy to cause the crystallization of epoxy resin, part of the epoxy resin because of the relationship between the composition, easy to present Granular, even the whole can become hard. At this time, the epoxy resin is not broken, but a crystallization phenomenon occurs. Knowledge expansion 1. Epoxy resin is sensitive to temperature, and it is very easy to convert liquid to solid in extremely cold environment or when the temperature fluctuates greatly, That is, crystallization of the epoxy resin occurs, which is a natural physical phenomenon. 2. Crystallization post-treatment: the crystallization of epoxy resin adhesive is also similar to the change of water freezing. After heating (heating), ice It will melt back into water. With this principle, we can usually use a water bath, a heater or a sun lamp. Hot. 3. Epoxy resin crystallization is a physical reaction, not a chemical reaction, so it will not affect the performance of the floor material. Introduction Introduction At room temperature, liquid bisphenol A epoxy resin (DGEBA,Digycidylether of Bis-phenol-A) and liquid bisphenol F epoxy resin (DGEBF,Digycidylether of Bis-phenol-F) are both supercooled liquids (supercooled liquid). That is, they are supposed to be solid at room temperature, but generally remain liquid at their solidification temperature. From a technical point of view, the freezing/melting point temperature of DGEBA is 45-50°C and DGEBF is 80-85°C. They are in the cold state because, at room temperature, "seed" (seed crystals) is not easy to form, and "seed" is a necessary condition for solidification, which leads to the crystallization process is very slow. As the average molecular weight of the resin increases, the large molecular weight component increases, and the isomer component also increases. These isomers and large molecular weight components reduce crystal formation and growth. The crystallization process is usually characterized by cloudiness (cloudiness), free-floating grains, clusters, or a completely solidified body. This process is the same as causing the crystallization of honey in the home. In all resins and curing agents, there is a possibility of crystallization. This is the phase transition of a substance from a liquid state to a solid crystalline state. The main component of most epoxy resins is a solid substance at room temperature. Extremely cold environments, hot and cold cycles, or other factors can cause crystals to grow and convert the substance to its natural solid state. The crystallization process is difficult to predict and difficult to avoid completely. It can happen without warning, or just affect the properties of a part of matter. For two-component systems, crystallization only brings some inconvenience in operation, but for single-component systems, it may be a big problem. Understanding the factors that cause crystallization to occur, as well as the methods of dealing with crystallization, can reduce this problem to a minor nuisance. Causes The crystallization principle of epoxy resin is similar to that of other substances. High purity, low viscosity, impurities, extremely cold environments, and hot and cold cycles will all increase the possibility of its occurrence. Typically the presence of "seed crystals" initiates crystallization. Here are some specific factors that cause epoxy resin to crystallize: High Purity In the high-purity resin, reaction by-products, impurities, and molecular weight distribution are removed within a limited range. The presence of by-products, as well as a wide molecular weight distribution, widens the liquid-to-solid transition temperature range. The transition temperature range of high purity epoxy from liquid to solid is very narrow. Similarly, the temperature at which pure water changes from a liquid state to a solid state (crystallizes) is 0°C. When some salt is added to the water, its crystallization temperature becomes lower. The closer the high purity resin is to this transition temperature, the greater the likelihood that minute crystals will begin to form. These microcrystals act as "seeds" that, under the influence of other factors, rapidly transform the liquid state into a solid state. Low viscosity Viscosity The molecular weight of the low-viscosity resin is very small, the molecular chain is very short, the lower the viscosity, the better the fluidity of the resin, the easier the orientation of the molecular chain near the "seed. High molecular weight and high viscosity substances have longer molecular chains and are less likely to crystallize. Storing the liquid resin without "seeds" at low temperature (0°C) can slow down the molecular chain movement and prevent the formation and growth of crystals. Diluents and modifiers generally promote the formation and growth of crystals, but the crystallinity of diluent molecular chains varies greatly. Other additives, such as pigments, fillers, wetting agents, etc. can also affect resin crystallinity. Generally speaking, if the introduction of "seeds" is prevented during processing operations, crystallization is still rare (except for high purity resins). Impurity Impurities Impurities, usually referred to as tiny particulate matter, tend to act as "seeds" in systems that do not contain fillers, initiating the formation of resin crystals and further continuing to expand the crystallization. Fillers rarely initiate crystallization, mainly because they are too bulky and present, and in practice they usually prevent crystallization. Ultra-low temperature Extreme Cold Although the low temperature will slow down the molecular chain movement, thus preventing the crystallization process, once the "seed" is formed, ultra-low temperature (-40°C) will accelerate the crystallization formation. If the temperature is low enough, the resin will automatically crystallize. Temperature cycle Temperature Cycles High and low temperature alternating 20-30°C will produce a vicious circle process, which is the most common reason for resin crystallization. Once the temperature of the system increases, the molecular chain movement ability is strengthened, so that the liquid epoxy resin molecules are aligned near the "seed. The system is then placed in a low temperature environment, and the alignment process is accelerated. Once initiated, the crystallization process continues until a solid mass is formed. The temperature difference between day and night will initiate and accelerate the crystallization process. This process occurs very quickly and may only be placed for a short time in the loading and unloading or production workshop. Solution Solutions The crystallization of the matrix resin and the two-component system only brings some inconvenience in operation, but it is not an insurmountable problem. Crystallization can be eliminated by heating the system at 50-60°C for several hours. When heating, make sure that all crystals are completely melted, otherwise any tiny unmelted crystals can act as "seeds" to re-initiate the system to crystallize again within a few days. In addition to heating carefully, agitate the resin in the container to ensure that the crystals on the wall and bottom of the container melt and the heat is evenly distributed in the system. If crystallization occurs again, just heat and repeat the melting process. One-component system can not be heated, because heating may lead to curing reaction, product deterioration. Controlling and monitoring the transport process and storage environment is essential to reduce temperature differences. Good storage measures are another important factor, such as ensuring that there is no resin residue on the inside of the pipe, valve, and lid after use to prevent crystallization from forming here. Although epoxy formulators and end users have placed great emphasis on preventing resin crystallization, this process is still very difficult to accurately predict and completely eliminate. If the crystallization phenomenon occurs repeatedly, it is necessary to evaluate some products that are not easy to crystallize as an alternative. Guangzhou Zhiye Chemical Co., Ltd. has been focusing on floor paint for 23 years. As a professional floor paint manufacturer established in the early stage of China, Zhiye has taken the lead in passing ISO management in the industry. It has always insisted on creating the greatest value for customers with continuous innovation, specializing in R & D, production, sales and application services of high-quality epoxy resin floor. Address (Address): 4/F, Deputy Building, Kerui Building, 336 Qingnian Road, Huangpu District Development Zone, Guangzhou Tel: 020-82057070 Web: www.gzzeal.com www.gzzeal.com 020-82057070 Long press scan code can be concerned

Epoxy resin crystallization

 

In the autumn, the temperature gradually lower, epoxy floor materials often encounter without curing agent on the hardening or produce particles

This is basically due to the crystallization of the epoxy resin.

 

Conditions for easy crystallization

1. When the epoxy resin is located at 10 ℃, the crystallization speed is the fastest.

2. The lower the chlorine content of the resin, the narrower the molecular weight distribution and the higher the purity, the easier it is to crystallize.

Some diluents are particularly easy to crystallize epoxy resin, such as BGE.

There are some chemicals that can induce the crystallization of epoxy resin, such as BPA.

Dust may also become the crystal nucleus of epoxy resin crystallization, inducing crystallization.

6, the filler may also accelerate the crystallization of epoxy resin.

The above is a variety of easy to cause the crystallization of epoxy resin, part of the epoxy resin because of the relationship between the composition, easy to present

Granular, even the whole can become hard. At this time, the epoxy resin is not broken, but a crystallization phenomenon occurs.

 

Knowledge expansion

1. Epoxy resin is sensitive to temperature, and it is very easy to convert liquid to solid in extremely cold environment or when the temperature fluctuates greatly,

That is, crystallization of the epoxy resin occurs, which is a natural physical phenomenon.

2. Crystallization post-treatment: the crystallization of epoxy resin adhesive is also similar to the change of water freezing. After heating (heating), ice

It will melt back into water. With this principle, we can usually use a water bath, a heater or a sun lamp.

Hot.

3. Epoxy resin crystallization is a physical reaction, not a chemical reaction, so it will not affect the performance of the floor material.

 

介绍 Introduction

 

At room temperature, liquid bisphenol A epoxy resin (DGEBA,Digycidylether of Bis-phenol-A) and liquid bisphenol F epoxy resin (DGEBF,Digycidylether of Bis-phenol-F) are both supercooled liquids (supercooled liquid). That is, they are supposed to be solid at room temperature, but generally remain liquid at their solidification temperature. From a technical point of view, the freezing/melting point temperature of DGEBA is 45-50°C and DGEBF is 80-85°C. They are in the cold state because, at room temperature, "seed" (seed crystals) is not easy to form, and "seed" is a necessary condition for solidification, which leads to the crystallization process is very slow. As the average molecular weight of the resin increases, the large molecular weight component increases, and the isomer component also increases. These isomers and large molecular weight components reduce crystal formation and growth.

 

The crystallization process is usually characterized by cloudiness (cloudiness), free-floating grains, clusters, or a completely solidified body. This process is the same as causing the crystallization of honey in the home. In all resins and curing agents, there is a possibility of crystallization. This is the phase transition of a substance from a liquid state to a solid crystalline state. The main component of most epoxy resins is a solid substance at room temperature. Extremely cold environments, hot and cold cycles, or other factors can cause crystals to grow and convert the substance to its natural solid state. The crystallization process is difficult to predict and difficult to avoid completely. It can happen without warning, or just affect the properties of a part of matter. For two-component systems, crystallization only brings some inconvenience in operation, but for single-component systems, it may be a big problem. Understanding the factors that cause crystallization to occur, and the methods used to handle crystallization, can reduce the problem to a minor nuisance.

 

Causes

 

The crystallization principle of epoxy resin is similar to that of other substances. High purity, low viscosity, impurities, extremely cold environments, and hot and cold cycles will all increase the possibility of its occurrence. Typically the presence of "seed crystals" initiates crystallization. Here are some specific factors that cause epoxy resin to crystallize:

 

High Purity

 

In the high purity resin, the reaction by-products, impurities, and molecular weight distribution are removed within a limited range. The presence of by-products, as well as a wide molecular weight distribution, widens the liquid-to-solid transition temperature range. The transition temperature range of high purity epoxy from liquid to solid is very narrow. Similarly, the temperature at which pure water changes from a liquid state to a solid state (crystallizes) is 0°C. When some salt is added to the water, its crystallization temperature becomes lower. The closer the high purity resin is to this transition temperature, the greater the likelihood that minute crystals will begin to form. These microcrystals act as "seeds" that, under the influence of other factors, rapidly transform the liquid state into a solid state.

 

Low viscosity Viscosity

 

The molecular weight of the low-viscosity resin is very small, the molecular chain is very short, the lower the viscosity, the better the fluidity of the resin, the easier the orientation of the molecular chain near the "seed. High molecular weight and high viscosity substances have longer molecular chains and are less likely to crystallize. Storing the liquid resin without "seeds" at low temperature (0°C) can slow down the molecular chain movement and prevent the formation and growth of crystals. Diluents and modifiers generally promote the formation and growth of crystals, but the crystallinity of diluent molecular chains varies greatly. Other additives, such as pigments, fillers, wetting agents, etc. can also affect resin crystallinity. Generally speaking, if the introduction of "seeds" is prevented during processing operations, crystallization is still rare (except for high purity resins).

 

杂质 Impurities

 

Impurities, usually referred to as tiny particulate matter, tend to act as "seeds" in systems that do not contain fillers, initiating the formation of resin crystals and further continuing to expand the crystallization. Fillers rarely initiate crystallization, mainly because they are too bulky and present, and in practice they usually prevent crystallization.

 

Ultra-low temperature Extreme Cold

 

Although the low temperature will slow down the molecular chain movement, thus preventing the crystallization process, once the "seed" is formed, ultra-low temperature (-40°C) will accelerate the crystallization formation. If the temperature is low enough, the resin will automatically crystallize.

 

Temperature cycle Temperature Cycles

 

High and low temperature alternating 20-30°C will produce a vicious circle process, which is the most common reason for resin crystallization. Once the temperature of the system increases, the molecular chain movement ability is strengthened, so that the liquid epoxy resin molecules are aligned near the "seed.

 

The system is then placed in a low temperature environment, and the alignment process is accelerated. Once initiated, the crystallization process continues until a solid mass is formed. The temperature difference between day and night will initiate and accelerate the crystallization process. This process occurs very quickly and may only be placed for a short time in the loading and unloading or production workshop.

 

Solution Solutions

 

The crystallization of the matrix resin and the two-component system only brings some inconvenience in operation, but it is not an insurmountable problem. Crystallization can be eliminated by heating the system at 50-60°C for several hours. When heating, make sure that all crystals are completely melted, otherwise any tiny unmelted crystals can act as "seeds" to re-initiate the system to crystallize again within a few days. In addition to heating carefully, agitate the resin in the container to ensure that the crystals on the wall and bottom of the container melt and the heat is evenly distributed in the system. If crystallization occurs again, just heat and repeat the melting process. One-component system can not be heated, because heating may lead to curing reaction, product deterioration. Controlling and monitoring the transport process and storage environment is essential to reduce temperature differences. Good storage measures are another important factor, such as ensuring that there is no resin residue on the inside of the pipe, valve, and lid after use to prevent crystallization from forming here. Although epoxy formulators and end users have placed great emphasis on preventing resin crystallization, this process is still very difficult to accurately predict and completely eliminate. If the crystallization phenomenon occurs repeatedly, it is necessary to evaluate some products that are not easy to crystallize as an alternative.

​

 

Guangzhou Zhiye Chemical Co., Ltd. has been focusing on floor paint for 23 years. As a professional floor paint manufacturer established in the early stage of China, Zhiye has taken the lead in passing ISO management in the industry. It has always insisted on creating the greatest value for customers with continuous innovation, specializing in R & D, production, sales and application services of high-quality epoxy resin floor.

 

 

 

Address (Address):

4/F, Deputy Building, Kerui Building, 336 Qingnian Road, Huangpu District Development Zone, Guangzhou

 

Tel: 020-82057070

 

Web: www.gzzeal.com

www.gzzeal.com

020-82057070

Long press scan code can be concerned

 

 

 

Related News