What is low density polyethylene and how is high density polyethylene and low density polyethylene d

A look at the PP forum, a lot of PE film information, there are many friends who make PE film, many of them are front-line operators, responsible for technology. There are many types of liquid made of PE particles, including low density, metallocene metallocene, linear type, etc.

Low-density polyethylene.

Low-density polyethylene (LDPE) is usually ethylene as a monomer, at 980 294MPa under high pressure, with.

Oxygen or organic peroxide is the initiator, and the polymer obtained by polymerization has a density of 0 910～0. 9259／cm3.

Medium density polyethylene (MDPE) density is 0 926 0 9409 cm3; Very low-density polyethylene (VLDPE).

The density is below 0 910g cm3.

Low-density polyethylene has long and short text chains on the molecular chains. The crystallinity is low, and the molecular weight is generally 5.5 million, and it is.

A milky white and translucent waxy solid resin, non-toxic. The softening point is low, and beyond the softening point is melting.

The hot melt bondability, molding processing performance is very good, the softness is good, the impact toughness and low temperature resistance are very good.

Working at 60 -80 °C, excellent electrical insulation (especially high frequency insulation), mechanical strength of LDPE.

Poor, heat resistance is not high, environmental stress crack resistance, adhesion, adhesion, poor printability, need to pass through the surface.

such as chemical erosion, corona and other treatments can improve its adhesion and printability. The water absorption is very low, almost none.

Water absorption, excellent chemical stability, such as acid, alkali, salt, organic solvent are more stable. To CO2, organic odor.

The permeability of gas is large, but the permeability to water vapor and air is poor. flammable, similar to paraffin when burning; In daylight.

It is easy to age and degrade and change color under the action of heat, from white to yellow to brown, and finally black, and the performance is reduced or turtle.

Crack, if a certain amount of antioxidants, ultraviolet absorbers, etc. can improve performance, in chemical crosslinkers or high-energy radiation.

By illuminating the cross-linking, it can improve the softening point, temperature resistance, stiffness, solvent resistance, etc.

Low-density polyethylene (LDPE) is suitable for various molding processes of thermoplastic molding processing Good molding processability, such as injection molding, extrusion, blow molding, rotational molding, coating, foaming process, thermoforming, hot air welding, thermal welding, etc.

LDPE is mainly used as film products, such as agricultural film, ground covering film, agricultural film, vegetable film.

shed film, etc.; packaging film such as candy, vegetables, frozen food and other packaging; Blown film for liquid packaging (milk,

Soy sauce, fruit juice. tofu, soy milk); Heavy packaging bags, shrink wrap films, elastic films, lined films; Build.

Construction films, general industrial packaging films, food bags, etc.

LDPE is also used in injection molded products, such as small containers, lids, daily products, plastic flowers, injection molding, stretching and blowing.

plastic containers. Medical appliances, pharmaceutical and food packaging materials, extruded pipes, plates, wire and cable cladding, different.

profiles, thermoforming and other products; Blow molded hollow molding products, such as food containers have dairy products and jams, medicines, etc

Cosmetic, chemical product containers, tanks, etc.

Release date: 2003-4-10

The difference between high-density polyethylene and low-density polyethylene:

1. Look at the color. High-density polyethylene (HDPE) is a white powder or granular product. Low-density polyethylene is milky white with a matte surface of waxy particles.

Second, the specific gravity method. The specific gravity of high density can be reached, and the low density is only.

3. Infrared spectroscopy analysis. Low-density polyethylene has many branched chains, and the peak peak at 1380 waves is obvious, representing methyl groups. HDPE, on the other hand, has few branched chains, and the peaks here are low or not guessed.

Dear, hello, I am glad to answer the difference between linear low-density polyethylene and low-density polyethylene A: First: Low-density polyethylene (i.e. LDPE resin) Properties:

Tasteless, odorless, non-toxic, matte surface, milky white waxy particles, density about, melting point 130 145. Insoluble in water, slightly soluble in hydrocarbons, toluene, etc. It can resist the erosion of most acids and alkalis, has low water absorption, can still maintain flexibility at low temperatures, and has high electrical insulation.

Production process: there are two main types: high-pressure pipe method and kettle method. Judging from the current development status, in order to reduce the reaction temperature and pressure, the tubular process generally adopts a low-temperature and high-activity primer initiation polymerization system, with high-purity ethylene as the main raw material, propylene propane and other density adjusters, and uses high-activity initiators to carry out polymerization reactions under the condition of about -300MPa.

The molten polymer that initiates polymerization in the reactor must be cooled and separated by high pressure, medium pressure and low pressure, the high-pressure circulating gas is cooled and separated and sent to the inlet of the ultra-high pressure (300MPa) compressor, the medium-pressure circulating gas is cooled and separated and sent to the inlet of the high-pressure (30MPa) compressor, and the low-pressure circulating gas is cooled and separated and sent to the low-pressure (travel rotten compressor recycling, and the molten polyethylene is sent to the granulator after high-pressure and low-pressure separation for pelletizing in water. Enterprises can add appropriate additives according to different application fields, and the granules are packaged and shipped out of the factory. Uses: Injection molding, extrusion, blow molding and other processing methods can be used.

It is mainly used as agricultural film, industrial packaging film, pharmaceutical and food packaging film, machinery parts, daily necessities, building materials, wires, cable insulation, coating and synthetic paper. Second: Linear low-density polyethylene (i.e. LLDPE resin) Properties:

Since the molecular structure of LLDPE and LDPE is obviously different, the performance is also different. Compared with LDPE, LLDPE has excellent environmental stress crack resistance and electrical insulation, high heat resistance, impact and puncture resistance, etc. Production process:

LLDPE resins are mainly produced in full-density polyethylene (HDPE) plants, and the typical production processes are the Innovene process and UCC's Unipol process. Uses: Through injection molding, extrusion, blow molding and other molding methods, the production of films, daily necessities, pipes, wires and cables, etc.

High-density polyethylene is an opaque white wax-like material.

High-density polyethylene is an opaque white wax-like material, the specific gravity is lighter than water, the specific gravity is, soft and tough, but slightly harder than LDPE, and slightly elongated, non-toxic, odorless.

High-density polyethylene is a highly crystalline, non-polar thermoplastic resin. The appearance of the original HDPE is milky white, and it is translucent to a certain extent in a thin cross-section. PE has excellent resistance to most domestic and industrial chemicals.

Advantages: good chemical stability, insoluble in any organic solvent at room temperature, resistant to acid, alkali and corrosion of various salts; The film has low permeability to water vapor and air and low water absorption.

Disadvantages: poor mechanical properties, poor air permeability, easy deformation, easy aging, brittleness, brittleness is lower than PP, easy stress cracking, low surface hardness, easy to scratch. It is difficult to print, and when printing, it needs to be treated with surface discharge, and the surface is not plated, and the surface is dull.

High-density polyethylene is the main use

High-density polyethylene resins can be molded into plastic products by injection, extrusion, blow molding, and rotational molding. Various types of containers, industrial accessories, medical supplies, toys, shells, stoppers and guards can be molded by injection molding.

Blow molding can be used to form a variety of hollow containers, ultra-thin films, etc. Extrusion moldable pipes, stretch strips, strapping tapes, monofilaments, wire and cable jackets, etc.

Linear low-density polyethylene (LLDPE) is a copolymer of ethylene and A-olefins. Its appearance is similar to that of ordinary low-density polyethylene; The density, crystallinity and melting point of linear low-density polyethylene are lower than those of high-density polyethylene, and the crystallinity is 50 55, which is slightly higher than that of low-density polyethylene, but much lower than that of high-density polyethylene; The melting point of linear low-density polyethylene is slightly higher than that of low-density polyethylene (generally 10 15 higher), but the temperature range of the melting point is very small; The mechanical properties of linear low-density polyethylene are better than those of ordinary low-density polyethylene, such as tear strength, tensile strength, impact resistance, environmental stress crack resistance and creep resistance. Electrical insulation is also better than low-density polyethylene; The film molded with linear low-density polyethylene is both soft and resistant to hot searches.

Summary. Dear, I am glad to answer for you: the difference between high-strength polyethylene and low-density polyethyleneA:

The density is different. Low-density polyethylene has less strength than high-density polyethylene and greater impact strength than high-density polyethylene. The stacking is different.

Low-density polyethylene is generally produced by high-pressure polymerization with a density of: The molecular structure of low-density polyethylene is a linear macromolecule with more branched chains, and its main chain is of different lengths. High-density polyethylene is produced by a low-pressure polymerization process and is linear in shape, with a density of 80%-95% and a white powder or granule.

with low-density polyethylene. The main uses are different. I hope mine can help you.

Dear, I am glad to answer for you: the difference between high-strength polyethylene and low-density polyethylene A: The density is different.

Low-density polyethylene has less strength than high-density polyethylene and greater impact strength than high-density polyethylene. The stacking is different. Low-density polyethylene is generally produced by high-pressure polymerization with a density of:

The molecular structure of low-density polyethylene is a linear macromolecule with more branched chains, and its main chain is of different lengths. High-density polyethylene is produced by a low-pressure polymerization process and is linear in shape, with a density of 80%-95% and a white powder or granule. with low-density polyethylene.

The main uses are different. I hope mine can help you.

Is high-strength polyethylene high-density polyethylene?

No, HDPE is high-density polyethylene, also known as low-pressure polyethylene. Compared with LDPE, it has high density, high strength and good hardness. LLDPE is linear low-density polyethylene, which is structurally different from general low-density polyethylene.