The Encyclopedia of Plastic Modifications that Plastics Professionals Should Know

The Encyclopedia of Plastic Modifications that Plastics Professionals Should Know

In practice, few plastics can fully meet specific application requirements; this requires us to make appropriate adjustments to physical properties of plastics; on other hand, according to actual market situation, we will meet requirements According to conditions to reduce cost as much as possible, so that you can take lead in fierce competition! The following four points, you must know following four points!

1. How to reduce cost of plastic?

Method 1, filling with inorganic substances

For thermoplastics, this is mainly cost reduction, and for thermosets, it is a combination of cost reduction and modification. In addition to cost reduction, bottling also improves some product properties. Generally, it is possible to improve stiffness, heat resistance (inorganic filler), dimensional stability, reduce molding shrinkage and creep resistance; some of them can also improve insulation, fire resistance, smoke suppression and sound insulation.

General packaging

● Filler CaCO3

● Talcum filler

● Wollastonite filler

● Kaolin filler

● Mica filler

● Diatomaceous earth filling

Formula Design Key Points

● Oil absorption of packing

If formulation system contains liquid additives, fillers with low oil absorption should be selected.

● Absorption of filler by resin

If formulation system contains liquid resin, fillers with low resin uptake should be selected.

The Encyclopedia of Plastic Modifications that Plastics Professionals Should Know


Second method: Inexpensive resin mixing

Mixing to reduce cost of plastics refers to process of mixing inexpensive resins or waste plastics with expensive resins to reduce costs. Compared to cost of filling and reducing amount of plastic, cost reduction is not very large, but it has advantage of having less impact on its own performance.

Among resins used, relatively inexpensive resins are mainly represented by seven types: PVC, LDPE, LLDPE, HDPE, PP and PS. The so-called mixing of cheap resins means mixing these resins.

2. How is plastic strengthened?

Plastic fiber reinforcement method

Plastic fiber reinforcement is most commonly used and effective reinforcement method. Reinforcing fibrous materials are most important reinforcing materials for plastics and their dosage can be over 90% of all reinforcing materials. Fibrous materials for reinforcement include two types of fibers and whiskers, as well as specific varieties:

● Inorganic: such as fiberglass, asbestos fiber, carbon fiber, filament, quartz fiber, graphite fiber, ceramic fiber, etc.;

● Organic: such as polyamide fiber, polyethylene fiber, polyamide fiber, polycarbonate fiber, PVC fiber, polyester fiber, etc.;

● Metals: such as boron fiber and aluminum, titanium, calcium and other metal whiskers.

The Encyclopedia of Plastic Modifications that Plastics Professionals Should Know

Plastic additives

3. How to change heat resistance of plastic?

First method, plastic filling

Among all fillers, except for organic fillers, most inorganic mineral fillers can significantly increase heat-resistant temperature of plastics.

Commonly used heat-resistant fillers are calcium carbonate, talc, wollastonite, mica, calcined clay, bauxite and asbestos. For example, maximum operating temperature of mica can reach 1000 degrees Celsius, and it is most efficient heat-resistant modified filler.

Second method, plastic reinforcement

The effect of plastic reinforcement on change in heat resistance is better than effect of filler, mainly because heat resistance temperature of most fibers is very high, and melting point in most cases exceeds 1500 degrees Celsius.

The most commonly used heat-resistant fibers include: asbestos fiber, glass fiber, carbon fiber, filament, polyamide fiber and acrylic fiber.

The Encyclopedia of Plastic Modifications that Plastics Professionals Should Know

Plastic products-tray

4. How to improve fire resistance of plastic?

Flammability of plastic

The burning temperature of most plastics is not very good. The following indicators are commonly used to measure fire resistance of resins:

● Oxygen Index (OI)

● American UL (UL-94)

The test method according to US UL standard is to observe burning of plastics when they are in direct contact with a fire source and analyze their fire resistance.

a. The V-0 level goes out within 10 seconds after leaving fire and does not ignite cotton wool 30 cm below it

b. B-1 will go out 10-30 seconds after leaving fire and will not ignite cotton wool 30 cm below it

c.V-2 will go out 30 seconds after leaving fire, but can ignite cotton wool 30 cm below it

Non-flammable material for adding to plastic

Flame retardants are commonly used in plastics to add flame retardants, which are a class of additives that can prevent plastics from igniting or inhibit flame propagation. Flame retardants are widely used additives in plastics formulations and their consumption is second only to fillers and plasticizers, making them third largest additives in plastics. There are many types of fire retardants, thousands have been reported, and more than a hundred of them are widely used.

The most commonly used flame retardants can be divided into: halogen compounds, phosphorus compounds, nitrogen compounds, organosilicon compounds and various inorganic substances according to their molecular composition, such as AI(OH)3, Mg(OH)2 and Sb2O3. etc.