What is the difference between rubber injection and silicone injection?

What is the difference between rubber injection and silicone injection?
Silicone and rubber are very common materials for daily necessities. They are used from sports shoe soles to swimming caps, aerospace military equipment to baby products, but you know how to distinguish the plastic products made by silicone injection or rubber injection? What is the difference between silicone injection and rubber injection? What are their suitable uses? Let us check together one by one today!

Material characteristics of rubber injection and silicone injection


There are many kinds of rubber. The common characteristics are wear resistance, good elasticity, and water resistance. Rubber can be divided into natural and artificial ones, and then other distinctions can be made from the purpose of the article. Rubber is very suitable for long-term use. Rubber injection is widely used.


Silicone is a very stable polymer, which is resistant to high and low temperatures, non-toxic and odorless. Silicone has a wide range of uses. It will not deform or release toxic substances when baked at high temperatures. It will be very safe while freezing food at very low temperatures. In addition, silicone is very soft and skin-friendly, so the equipment worn is often made of silicone injection.

Injection principle 

Rubber injection

Rubber has good elasticity. It will deform when under pressure, but it will quickly return to its original shape. Therefore, during the production process of rubber, relatively large pressure is required for the finished product to be molded. Because of this, although there are many types of rubber, most rubbers can only be made by injection molding and compression molding. Compression molding is an early rubber molding method. It refers to pressing a piece of rubber directly into a mold, then heating it to melt, and then cooling molding to obtain the finished product. The rubber injection molding method is similar to the common plastic injection, but the pressure required is small, which also makes rubber injection become the most common way of making rubber products.

Silicone injection

Silicone is a kind of thermosetting material, so the raw material that has not been processed is usually liquid. Therefore, before the silicone is injected, the silicone material (A) and the firming agent (B) are usually mixed, and even if there is a color requirement, the liquid is added Toner agent (C), mix well after mixing, heat the molding. It is important while building the mold because the raw material of silicone is liquid and has good fluidity, if the mold is not tight enough, there will be joints. In addition, silicone is often used to make utensils related to food or wearables. Therefore, special attention should be paid to the material of the mold and the nature of the additives to avoid contamination of the finished product.
〈Extended reading: Can general injection machines inject molded silicone materials? 〉

Common applications of rubber injection and silicone injection

Rubber injection

1. Natural rubber (NR)

Natural rubber is collected from rubber trees. It has good abrasion resistance, elasticity and tensile strength. The disadvantage is that it is not heat resistant and easy to age. After rubber injection process, natural rubber can be used to make tape, rubber shoes, and can be used to make shock absorption components.

2. SBR (SBR)

Compared with natural rubber, styrene butadiene rubber has more uniform quality, less foreign matter, better abrasion resistance, anti-aging performance is much better than natural rubber, and has very good water resistance, and the cost is relatively low. SBR is widely used in tire industry, shoe industry and cloth industry.

Silicone injection

Silicone is uniquely non-toxic, odorless, and resistant to high and low temperatures. It can be used for baking in a microwave oven along with the ingredients during baking, and frozen in the refrigerator. It can also be used to make baby pacifiers and smart watch straps. Even in the industry, it is often used as insulating and sealing materials, which makes the food, electronics, and medical industries often use silicone products.


Silicone injection and rubber injection, each has its own advantages, disadvantages and characteristics, and they also have their own suitable uses. If your company wants to develop durable products and not focus on the demand of apperance, the recommended rubber injection will suit your needs; if the non-toxic and odorless material of your product, and certain requirements for the design, the semi-transparent material of the silicone is the first choice, which can take the product texture to a higher level.

We are the injection machine experts who have been professionally operating for many years in the local area. If you have any doubts about the rubber injection and the silicone injection, feel free to contact us any time.
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