Introducer
In the production of polyurethane products, it is necessary to use release agent to help the molded products to separate from the mold. Among the demoulding agents that can be directly used in the production line, the substances with demoulding performance are called effective demoulding components, which can generally be wax, organosilicon, organic fluorine, etc., generally accounting for less than 10%. More than 90% of them belong to the solvent component, which is used to help the effective mold release component to form a uniform film on the mold surface. In this issue, let's discuss the application of lower solvent in polyurethane release agent.
Polyurethane products? Polyurethane (polyurethane) products are a series of products which are produced by polyurethane as the basic raw materials in the market. Polyurethane products include polyurethane foam (soft foam and rigid foam) and CASE system (paint, adhesive, sealant, elastomer, etc.). The main consumption areas of polyurethane products in China are: furniture industry, construction industry, leather industry, shoe industry, household appliances industry, sports industry, transportation industry, etc.
Polyurethane products overview
type
raw material
application
Rigid foam
Polymeric MDI, polyether polyester polyol, HCFCs foaming agent, catalyst
Refrigerators, freezers, cold chain logistics and other fields of heat insulation and energy conservation of building walls
Soft foam
TDI, polyether polyol, foaming agent, surfactant, catalyst
Lining materials in car seats, furniture and fabric cushions
coating
TDI, MDI, HDI, IPDI, acrylic polyol, polyether or polyester polyol
Automobile repair paint, wood coating, floor paint, leather rubber paint, high-performance anticorrosive paint
An adhesive
Polyester, polymdi, BDO, solvent
Adhesion of metal to nonmetal (plastic, rubber, wood)
sealant
MDI, polyether polyol, acrylic polymer
Construction sealant, automobile windshield bonding seal
Elastomer
Pure MDI, aliphatic polyester or polyether polyol, diamine chain extender, catalyst
Automotive wheels, industrial forklift wheels, elastomers for shoes and car runways
fibre
Pure MDI, PTMEG
Suitable for clothes with high tensile strength and supporting function
Sole fluid
Pure MDI, AA, DMF
Leather shoes, sports shoes, plastic shoes, cloth shoes, etc
size
Pure MDI, adipic acid, BDO, DMF
Clothing and textile fields such as bags and shoes
Release agent? When the filling material is formed and processed in the mold, the contact between the filling material and the surface of the mold may be due to the micro defects such as concave convex of the working surface of the mold, so that the formed products will have certain friction resistance when peeling off from the mold. In the process of injection or extrusion of filling materials, negative pressure is often formed between the filling materials and the mold, or the physical adsorption or chemical bonding between the two causes the knot, which makes it difficult to peel the filling materials from the mold after molding. In order to weaken the absorption or the gap between the product and the mold, the additive (mold release agent) which can form an effective separation film is often used. The release agent is a layer of film that is used on two surfaces that are easy to open and close to each other, so that the gap between the object and the object can be isolated, so that it can be easily stripped, making the product demoulding easier and more convenient.
Broad sense release agent includes many types, which are applied in chemical industry, metallurgy, building materials and other fields. This time, only limited to the field of chemical release agents, mainly discusses the application changes of solvents in polyurethane and other materials forming and processing release agents.
We start from the first stage of solvent application in polyurethane release agent. At first, industrial production did not consider the environmental protection and safety of raw materials, but only the pursuit of high solubility and volatile. People's demand for solvents is limited to diluent considerations, which require rapid evaporation of the spray after mold, so as to avoid bubble defoaming. Therefore, some organic solvents are widely used because of their high solubility and volatile characteristics, such as:
(1) Dichloromethane: strong solubility, volatile at room temperature, chemical stability, and because there is no flash point, it will not lead to combustion, low price. This is a very ideal solvent choice, and it is also widely used in the early stage. However, the high concentration of dichloromethane vapor will cause poisoning, and a large number of emissions will also cause greenhouse effect. Jinjiang, once the capital of shoe materials, was filled with thousands of dichloromethane before environmental release agents were widely used in shoe material production.
(2) Petroleum ether: it is a low boiling point fraction of petroleum, which is a mixture of low-grade alkanes. It is usually used as a solvent with a boiling range of 30-60 ℃, and has high volatility. In the early days, it was widely used in mold release agent. Because of the low boiling point fractionation, benzene and aldehyde ketone are easily mixed into the product, resulting in the overall VOC and odor are not friendly.
(3) Naphtha: also known as crude gasoline, mainly composed of c5-c11 of alkanes, with a flash point of - 2 ℃, which is very volatile and flammable. The volatilized steam can stimulate the eyes and upper respiratory tract of human body, and also pollute the environment.
(4) Xylene: C8H10, isomer, distillation range about 140 ℃, high flash point flammable, irritant odor, category 3 carcinogen.
(5) Quick drying water: cyclohexanone, colorless or light yellow transparent liquid, with strong irritant odor, category 3 carcinogen. We can see that the above products only pay attention to the use characteristics, but ignore the long-term impact on human body and the environment. Therefore, in the current society with the theme of environmental protection, the market share is becoming smaller and smaller, and they are used on the low-end products. Some of the products listed in the list of carcinogens are forbidden to be used.
In the second stage, people with health awareness began to look for new solvent substitutes with low toxicity. Heptane, a colorless volatile liquid, has been widely used as a solvent of release agent because of its high fat solubility, high volatility and strong decontamination ability. It is commonly known as white electric oil, scientific name is n-heptane, flash point - 4 ℃, belonging to extremely flammable organic solvent. The price of pure heptane is relatively high, so there is an industrial heptane. The industrial products contain more impurities such as aromatics, sulfur, nitrogen and other compounds, so the product odor and VOC performance are poor. At the same time, the toxicity of heptane is lower than that of the initial solvent, but with the long-term use, there is also a potential risk of chronic poisoning, mainly manifested in the damage of human peripheral nerves, so heptane has gradually sunk into the solvent for low-end products.
At the beginning of the third stage, the coming environmental protection and safety inspection forced the manufacturers to pay attention to the environmental protection and safety issues. The solvent products with relative safety and environmental protection are the direction that the mold release agent manufacturers are looking for. At this time, the dearomatic solvent oil came into being. At present, dearomatic solvent oil is mainly produced by high-pressure hydrogenation at both ends of aviation coal, deep desulfurization and dearomatization, and then rectification. Desulfuration can eliminate peculiar smell and corrosiveness. Aromatization can reduce harmful substances of benzene and improve VOC performance. At present, the market is divided into several models (i.e. D40, 60 and other D series solvent oil) according to the flash point of solvent. Because the boiling point of pentaphenyltrialdehyde is low, the higher the distillation range of the product, the lower the content of harmful substances in the solvent product itself. The low toxicity of dearomatic solvent oil has little effect on personal safety and production environment, and the higher flash point also brings higher safety for production. However, due to the slow volatilization of high distillation range products, it is easy to cause the surface defoaming of polyurethane products, which is a factor that is not convenient for the application of mold release agent, so the range of use at the beginning is more locked in the relatively volatile solvent.
From the fourth stage, environmental protection has higher requirements for the safety of products, storage, logistics and transportation produced by enterprises, the living space of dangerous chemicals is shrinking day by day, and the operating cost is rising day by day. How to transform the release agent from dangerous chemicals to non dangerous chemicals has become a new topic. The water-based release agent with water as the main solvent has long been considered by manufacturers. At present, it has been widely used in shoe material, metal die casting, carpet, front wall sound insulation pad, steering wheel and other fields. The evaporation rate of water is the slowest, even if the water-based release agent can solve all the environmental protection and safety problems brought by organic solvent once and for all. However, in the seat sponge production line, because of the complex structure of the seat mold, the high sensitivity of the high speed and high resilience foam surface, the application technology of the water release agent is extremely harsh and inconvenient. Therefore, the manufacturers prefer to choose flash point > the organic solvent at 60 C is the high flash release agent for the carrier. According to the national classification standard for flammable liquid, the liquid with flash point & gt; 60 ℃ is not a dangerous chemical, and can be transported and stored according to common chemicals. Although the release agent with high flash point volatilizes slowly, it is still faster than water. It can still meet the requirements of production through the adjustment of spraying technology. Therefore, high flash point solvent oil has entered the use range in this stage.
In the fifth stage, odor and VOC become the main directions. The interior environment of high-end vehicles is extremely demanding, but the rectification is driven by the first level supplier, so higher requirements are put forward for release agent, and the ideal goal is no smell and VOC. Although the content of VOC in dearomatic solvent oil is small, it still has a special solvent odor. Therefore, before the application of water-based release agent is fully mature, release agent manufacturers can only continue to look for alternatives in organic solvents. Finally, the isoalkanes that can be used in the field of personal care and cosmetics have entered the application range. They are colorless, tasteless, high purity, single component, free of aromatics and sulfur, real low toxicity and good solubility. These characteristics make the isoalkanes become the highest end products in environmental protection solvent oil. At present, there are three production processes of isoalkanes: aromatization of straight chain alkanes, synthesis of isobutylene and CTL Fischer Tropsch synthesis of coal to gas. Isobutylene is mostly used in the synthesis of foreign imported products, which is produced by cracking naphtha to isobutylene, and then through isomerization, distillation and hydrogenation, the high-purity synthetic isobutylene is finally obtained, which is completely tasteless at room temperature, and will not have peculiar smell when heated to a certain temperature. However, due to the high comprehensive cost of the process, the solvent price is high, which is more than two times of that of the environmental solvent oil Currently, it can only be used for high-end products. Due to the abundant coal resources in China, CTL Fischer Tropsch synthesis of isoalkanes has become the mainstream research and development route. With the later stage process becoming mature, it is believed that the price of domestic isoalkanes will be greatly reduced, and the consumption will be explosive growth.
To sum up, in the mold release agent industry, it's the same thing that the price determines the quality of products to a certain extent. Low price can't meet high-end demand, and high price is more to share the R & D cost in the early stage. The R & D and innovation path (Evolution History) of our company's Wuyang hydrocarbon solvent oil is basically in step with the above-mentioned manufacturers' demand for solvent. Therefore, our company has sufficient voice in the application of solvent oil. Wuyang is willing to share experience, exchange experience and common innovation and progress in the field of solvent oil technology.
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Welcome to call 400-1166-20513584124188 on the comparative advantage of isoalkane solvent