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What plastic shell shall we choose for knee pads? PP, TPR, TPU, PE Plastic Shell on Knee Pads

Posted on by Vanotool

As we all know, we can always see different plastic products in our lives. Today we will talk about the plastic accessories used in knee pads, which are basically made of PP, TPR, TPU, SEBS, PE, UHMW, ABS and other materials. They can all play a protective role, but you need to find suitable materials for different occasions.

PE plastic cap shell on knee pads, for example below:

Polyethylene (PE) is a thermoplastic resin prepared by polymerization of ethylene monomer. In industry, it also includes copolymers of ethylene and a small amount of A-olefin. Polyethylene is odorless, non-toxic, feel like wax, with excellent low temperature resistance (the lowest use temperature can reach -100~-70°C). Good chemical stability, because the polymer molecules are connected by carbon-carbon single bonds, resistant to most acid and base erosion (not resistant to acids with oxidizing properties). Insoluble in general solvents at room temperature, low water absorption, good electrical insulation

Polyethylene can be divided into high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE) and ultra high molecular weight polyethylene (UHMWPE) according to different polymerization methods, molecular weight and chain structure.
 

 

PP plastic cap shell on knee pads, for example below:

PP plasctic, full name Polypropylene, a kind of plastic, is a linear polymer with high density, no side chains, and high crystallinity, and has excellent comprehensive properties. Common products: basins, barrels, furniture, films, woven bags, bottle caps, car bumpers, etc.
pp plastic, chemical name: polypropylene English name: Polypropylene (pp for short) Specific gravity: 0.9-0.91 g/cubic centimeter Molding shrinkage: 1.0-2.5% Molding temperature: 160-220°C PP is a crystalline polymer, PP The overall performance is better than PE material. PP products are lightweight, tough and chemically resistant. Disadvantages of PP: low dimensional accuracy, insufficient rigidity, and poor weather resistance. It has post-shrinkage phenomenon. After demoulding, it is easy to age, become brittle, and deform. In daily life, commonly used crisper boxes are made of PP material.

TPU and TPR plastic widely used on army knee pads

TPU (thermoplastic polyurethane) is a synthetic rubber material with high elasticity and wear resistance, which is often used to make insoles, tires, gears and other high-strength parts. The following are the advantages and disadvantages of TPU materials: Advantages: 1. High strength: TPU has high tensile strength and tear strength, higher than most synthetic rubber and natural rubber.

Advantage:
 
 
1. High strength: TPU has high tensile strength and tear strength, higher than most synthetic rubber and natural rubber.
2. Wear resistance: TPU has good wear resistance and can maintain its shape and performance during long-term use.
3. Oil resistance: TPU has good oil resistance and can be used to manufacture seals, bearings and other parts that need to be resistant to oil stains.
4. Cold resistance: TPU can maintain its elasticity and performance at low temperatures, so it is suitable for use in cold environments.
5. Good processability: TPU can be processed by injection molding, extrusion, calendering, etc., and the surface of the molded product is smooth.
6. Environmentally friendly: TPU materials can be recycled and reused and are environmentally friendly.
 
Shortcoming:
 
1. Higher price: Compared with some other synthetic rubber materials, TPU is more expensive.
2. Not resistant to high temperatures: TPU easily softens and deforms under high temperatures and is not suitable for use in high temperature environments.
3. Not resistant to ultraviolet rays: TPU is easily affected by ultraviolet rays and ages and deteriorates, and is not suitable for long-term exposure to sunlight.
4. Not resistant to acid and alkali: TPU has poor resistance to acid and alkali and is easily corroded by chemical substances and loses its performance.