Injection PP has bubbles:

PP bubbles solve problem 1:

1. Increase mold temperature, reduce time and cycle [because PP bubbles are formed due to internal shrinkage caused by too long cooling time];

2. Increase the back pressure, prolong the injection time, use high pressure and low speed;

PP generally does not have bubbles (due to small moisture absorption), which may be a problem with the filler when PP material is granulated. If the solution in the process is:

1. Add spare materials to dry;

2. Injection back pressure increases, injection injection injection speed slows down;

3. The temperature of the barrel should not be too high;

Originally, PP material is a very good material to operate, first consider your mold structure, where the bubble is formed; The bubble temperature should not be too high, and then pay attention to the thickness of the product, as well as no glue or less glue; In fact, the injection efficiency should not only look at the parameters, more analysis of the problem is the king, and the adjustment is not to look at the five elements of molding.

PP bubbles solve problem 2:

1. Storage speed is too fast, appropriate back pressure;

2. The drying degree of raw materials is not enough, containing moisture;

3. The plastic stays in the barrel for too long;

4. The screw ejection is too long;

5. Mold exhaust bad;

6. Injection pressure is too small, injection speed is too large;

7. The melt temperature is too high, the mold temperature is too low;

The characteristics of polypropylene PP plastic; And the use of polypropylene PP:

Non-toxic, tasteless, low density, strength, stiffness, hardness and heat resistance are better than low pressure polypropylene, can be used at about 100℃, has good electrical properties and high frequency insulation is not affected by humidity, but low temperature becomes brittle, no wear, easy aging, suitable for manufacturing general mechanical parts, corrosion resistant parts and insulation parts. Common acid-base organic solvents have little effect on it, and the appropriate brand can be used for eating utensils.

Physical properties of PP:

Polypropylene is usually a translucent colorless solid, non-toxic and odorless. The melting point of polypropylene is about: 164-170℃, and the density is 0.91g/cm². High strength, high hardness, wear resistance, bending fatigue resistance, moisture resistance and chemical resistance are good, easy to process molding, low price, so large output, widely used general polymer varieties; The disadvantage is poor toughness at low temperature and aging resistance. However, it can be overcome by modification and addition of antioxidant respectively.

Mechanical properties of PP:

Polypropylene has high crystallinity and regular structure, so it has excellent mechanical properties. However, at low temperature and room temperature, the impact strength is poor due to the high degree of regularity of its molecular structure. Its most outstanding property is resistance to bending fatigue.

Thermal properties of PP:

Polypropylene has good heat resistance, products at temperatures above 100 ° C for disinfection and sterilization, under the condition of no external force, 150 ° C does not deform the catalytic temperature of -35 ° C, below -35 ° C will occur embrittlement, cold resistance is not as good as polyethylene.

Chemical stability of PP:

The chemical stability of compact propylene is very good, in addition to being eroded by concentrated sulfuric acid, concentrated nitric acid, and other chemical reagents are relatively stable; However, low molecular weight aliphatic hydrocarbons, aromatic hydrocarbons and chlorinated hydrocarbons can soften and dissolve polypropylene

At the same time, its chemical stability is also improved with the increase of crystallinity, so polypropylene is suitable for the production of various chemical pipes and accessories, and the anti-corrosion effect is good.

Electrical properties of PP

The high frequency insulation performance of polypropylene is excellent, because it almost does not absorb water, so

Insulation performance is not affected by humidity. It has a high dielectric coefficient, and

As the temperature rises, it can be used to make heated electrical insulation products.

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Its breakdown voltage is also very high, suitable for use as electrical accessories. antielectric

Good voltage and arc resistance, but high static electricity, easy to aging with copper.

PP weather resistance

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