PVC hose plastic granulation process

Granulation process is a polymer resin and various additives, additives, after measurement, stick together, plasticizing, pelletizing made of granular plastic production process, the plastic pellet is the plastic forming and processing industry, semi-finished products, but also extrusion , Injection molding, hollow blow molding, foam molding and other production of raw materials.

Resin powder and granular two.

Granulation by extrusion is the most basic and simple granulation method, widely used.

For a variety of plastic molding processing methods, the use of pellet processing and powder processing directly compared to the advantages of pelletized pellets are as follows:

(1) feeding convenient, do not need to install in the hopper forced feeder.

(2) The relative density of pellets than powder material, plastic products better strength.

(3) resin and a variety of solid powder or liquid additives mixed more evenly, the physical properties of plastic products more evenly.

(4) plastic products, uniform color.

(5) less particulate material containing airborne volatile substances, so that plastic products are not easy to produce bubbles.

(6) pellets on the extruder and the production environment without pollution.

Production Process:

1, ingredients before the preparatory work

Preparations before the ingredients include screening the resin, plasticizer filtration, powdered additive refining, masterbatch powder preparation of raw materials drying, block additive heating and melting processes.

Polymer resin in the production, packaging, transportation process may be mixed with mechanical impurities or other impurities, in order to prevent damage to granulation equipment and reduce product quality, the resin must be used after sieving, PVC powder generally used 40-mesh screen, Granular polyethylene or polypropylene sieved, can be slightly larger than the resin size of the fine mesh sieve.

In order to prevent plastic impurities or black rubbish mixed into products, affecting product performance, the production of cable materials, plasticizers generally filter with 60 ~ 120 mesh filter [60 with a high viscosity, with a small viscosity of 120 mesh.

The coarse particles or easy clumping powder additive, the best plasticizer refining, adding slurry, mixed dispersed in the resin more evenly. The grinding equipment is a three-roll mill. The ratio of the general additive to the plasticizer in the refining formula is about 1: 1, and the fineness index of the slurry is 60 to 80 μm.

The proportion of the slurry formula is the ratio of parts by weight, the proportion of the size of the powder is mainly based on the apparent density of the size to be set, the apparent density of the powder, need to add a large number of plasticizers. Plasticizers generally use small viscosity DOP. Plasticizer in the amount of feeding, should be deducted when adding the amount of refining.

Of rigid PVC products, because they do not join the plasticizer, the general is to create a high concentration of PVC masterbatch powder, and then added to the kneader mixing. For example, hard PVC pipe dyeing are used in this method. Color masterbatch powder kneading machine should be added with stabilizer, to prevent resin decomposition.

For hygroscopic resins and additives, the water must be dried before kneading or extruding. For example, nylon resin and ABS resin are easy to absorb water, must be dried to a moisture content of less than 0.1%, drying equipment are: boiling dryer, vacuum dryer or vacuum drying hopper.

Some functional masterbatch, such as antistatic masterbatch, anti-blocking masterbatch, pearlescent masterbatch, filler masterbatch, etc. are easy to absorb moisture, should be dried before adding extruder, otherwise it will affect the production or reduction of products quality.

As a block of stearic acid and paraffin are plastic processing more lubricant. If directly added to the kneader, high-speed kneading machine due to high-speed rotation hit the baffle, damage to the baffle, it must be heated and melted into the kneader. Stearic acid has a melting point of 69.60 ° C and paraffin wax has a melting point of 60 ° C.

2, the formula weighing

Into the kneading machine or mixer for mixing, mastication of raw materials, the first volume should be based on equipment and feeding coefficient, estimated feed.

Accurate weighing according to the amount of feeding, weighing must be accurate, otherwise it will make the product quality is not stable. Weighing and weighing devices and automatic metering devices should be regularly checked and corrected to prevent quality errors caused by measurement errors.

3, kneading

Kneading can be divided into heating kneading and cooling kneading, with a high-speed kneader.

Heating and kneading process conditions: soft polyvinyl chloride kneading time 10 ~ 15min, the material temperature 95 ~ 100 ℃; rigid polyvinyl chloride kneading time 5 ~ 10min, the material temperature 100 ~ 110 ℃. In addition, the order of addition during kneading has an influence on the kneading quality.

Cooling kneading High-speed kneading machine out of the material temperature is higher, more than 100 ℃, if placed in storage cylinder, prone to discoloration, clumping or even material decomposition. Therefore, the need for immediate cooling and mixing, the material temperature dropped below 50 ℃, can be stored for the extruder. Cooling and mixing conditions Both soft and hard PVC are kneading time 5 ~ 10min, the material temperature below 50 ℃.

Mixing with 50L mixer, mixing soft polyvinyl chloride and polyethylene masterbatch process conditions are as follows, flexible vinyl chloride mixing time 3 ~ 5min, mixing temperature 90 ~ 110 ℃, the material temperature 100 ~ 110 ℃; polyethylene mixing time 8 ~ 10min, mixing temperature 80 ~ 100 ℃, the material temperature 140 ~ 145 ℃. Good mixing materials for the group like material, can not have unplasticized powder or granular material release.