Introduces the basics of plastic lubricants-Iota

Products

News

Office Address:	Sunmoon Science Park, 985 Xingzhong Road, High-Tech Zone, Bengbu, China
Factory Address:	Mohekou Industrial Park, Huaishang District, Bengbu, Anhui, China
Contact:	Nathan Zhang
Phone:	0086-552-19805521900
FAX:	0086-552-3822922
Mobile:	19805521900/18119733779
WebSite:	www.siliconeoil.cn www.siliconeoil.net
Email:
QQ:	729118868

News > Dynamic industry > Introduces the basics of plastic lubricants

Introduces the basics of plastic lubricants

After the molten polymers typically have higher viscosity, in the process, when the molten polymer through the slit, like the gate runner, the polymer melt must be friction surface and processing machinery, and some Friction in the processing of polymers is very negative, which reduces the friction of the melt flow, while serious friction causes the film surface becomes rough, lack luster or appear rhyolite. To do this, need to be added in order to improve lubricity, reduce friction, reduce interfacial adhesion properties for the purpose additives. This is the lubricant. In addition to improved lubricant flow, but also can play a molten accelerators, anti-adhesion and anti-static agents, slip agents effect.
Lubricants can be divided into two kinds of external lubricant and lubricant inside and outside friction lubricant role is mainly to improve the polymer melt processing equipment with hot metal surfaces. It is less compatible with the polymer, migrate out easily from the melt, so the lubrication can be formed in a thin layer of the plastic melt and metal interface. The lubricant with the polymer have good compatibility, which serve to reduce the role of cohesion between the polymer molecules within the polymer, thereby improving the plastic melt internal friction heat and melt flowability. Common external lubricant is stearic acid and its salts; the lubricant is a low molecular weight polymer. Some lubricants have other functions. Each lubricant has actually can achieve a required action, internal and external lubrication always together, but in a way more prominent. With a lubricant under different polymers or different processing conditions exhibit different lubricating effect, such as high temperature, high pressure, the lubricant will be squeezed out and become external lubricant.
In the production of plastic film, we will encounter some adhesion phenomena, such as in the production of plastic film, the film is not easy to separate the two, which brought difficulties to the automatic high-speed packaging. To overcome it, the resin can be increased by adding a small amount of surface lubricity additives to increase the external lubricity, generally referred to as an anti-blocking agent or slip agents. Molecular structure of the lubricant in general, there will be long chain non-polar group and a polar group in two parts, in which the compatibility of the different polymers are not the same, thus showing different internal and external lubrication. According to the chemical composition, conventional lubricants can be classified into the following categories: fatty acids and their esters, fatty acid amides, metal soaps, hydrocarbon, organic silicon compounds and the like.
Lubricant has efficacy in a variety of plastic of the actual processing, for example, in kneading, during calendering, the polymer can be prevented from sticking barrel, suppressing friction and heat, reducing the kneading torque and load, thereby preventing the polymer material thermal deterioration. During extrusion molding, to improve flowability, the polymer material and to improve adhesion of the barrel and the die, to prevent and reduce retentate. Another film but also to improve the appearance and gloss.
From the point of view of processing machines, kneading, calendering, slush molding process, etc., external lubricants have an important role in extrusion, injection molding, the lubricant is more effective.
The amount of lubricant is generally in the 0.5% to 1%, the choice should pay attention to:
1. The flow properties of the polymer has to satisfy the needs of the molding process, the main consideration of the role of external lubrication in order to ensure internal and external balance;
2. external lubrication is valid, it should be able to at the molding temperature in the surface layer of plastic film to form a complete liquid prevail, and therefore outside the lubricant should be close to the melting point of the molding temperature, but a difference of 10 ℃ ~ 30 ℃ can only form a complete film;
3. do not reduce the mechanical strength and other physical properties of the polymer.
When selecting a lubricant in production, should be made to achieve the following requirements:
4. Lubricate high efficiency and long-lasting;
5. Compatibility with the resin of moderate size, internal, external lubricating balance; not blooming, easy to scale;
6. The surface gravity is small, small viscosity at the interface scalability, easy to form the interface layer;
7. Try not to reduce the excellent properties of the polymer, does not affect the secondary processing properties of plastics;
8. itself is excellent in heat resistance and chemical stability, does not decompose during processing, non-volatile;
9. The non-corrosive, non-pollution film, no toxicity.
However, the mere use of a lubricant is often difficult to achieve the purpose, to be used in combination of several lubricants, lubricating composite developed rapidly in recent years, the choice may be to look at the role of multi-angle lubricant.
Commonly used lubricants are stearic acid, butyl stearate, oleamide, ethylene bis stearamide and the like.
Many substances can be used as a lubricant wax, such as natural paraffin, liquid paraffin (white oil), microcrystalline wax, etc., but the effect was mixed. Natural waxes more used by the external lubrication, the lubricant can be used as a variety of plastics, a mold release agent, generally used in an amount 0.2 ~ 1phr, but the compatibility, thermal stability and dispersibility is not good, the amount can not be too large, and preferably within the lubricant and use; and shortening much used PVC, PS of internal lubricant, good lubricating properties, thermal stability is also very good, the general amount 0.5phr. They are no drugs that can be used for food packaging. Another kind of microcrystalline wax: in Plastics Processing It is also used as a lubricant, the amount of 1 ~ 2Phr, good thermal stability and lubricity than regular paraffin.
Low molecular weight polymer is also widely used as a lubricant, such as polyethylene wax, low molecular weight polypropylene, the inner, outer lubricating properties are good, and non-toxic. Polyethylene wax and other materials suitable for PVC extrusion, calendering, dosage is generally 0.1 ~ 1phr, can improve processing efficiency, to prevent film blocking, to improve the dispersibility of fillers or pigments, compatibility and transparency is not very good; irregular Structure of low molecular weight polypropylene can be used as the hard PVC, PE lubricant, excellent performance, can improve the dispersibility of other additives, in the amount of 0.05 ~ 0.5phr.

分享到

Feedback to "Iota Silicone Oil (Anhui) Co., Ltd."