Among the silicone mold parts, there is a very important medical application scenario, which is the respiratory mask. The gas mask structure is composed of hard plastic and soft rubber materials. The silicone mask is inseparable from the most basic silicone prototype
Process. At present, hard plastics usually use environmentally friendly food-grade polypropylene PP. There seems to be a lot of room for the choice of soft rubber materials, such as soft PVC, silicone, rubber, elastomer, and PU.
Application of silicone mold parts
Gas masks were originally born with the killing of chemical weapons, and are a kind of protective equipment to protect the personal respiratory tract against poisonous gas. The material of today’s gas masks has been changed from ordinary rubber to silicone rubber and thermoplastic elastomer TPE. In the peaceful era, it was more used in industrial production processes. This is a typical silicone mold parts application case.
What is a medical silicone prototype?
There are various styles and designs of gas masks. One type of gas mask that I have seen a lot (as shown in the figure below) is a composite of hard plastic and soft rubber materials. The hard plastic is mainly used to support the mask polypropylene and make air circulation, and the soft plastic material is mainly considered the comfort for people wearing it on the face and in contact with the human body. At present, hard plastics usually use environmentally friendly food-grade PP. Through silicone prototype, we The manufacturability of silicone parts can be quickly assessed.
There seems to be a lot of room for the choice of soft rubber materials, such as soft PVC, silicone, rubber, elastomer, and PU. However, after comprehensive consideration by the manufacturer, at present, when the gas mask is produced, its soft rubber material basically uses two materials-silicone and TPE/TPR rubber compound.
silicone gas mask
Why did the gas mask finally choose silicone and TPE as the raw materials for the soft rubber part? This is mainly based on the following three considerations:
1. Environmentally friendly and non-toxic
Silicone is an environmentally friendly material that everyone agrees with. Food-grade silicone can provide the US FDA177.2600 test and is a material that can come into contact with food. In addition, the silicone has no odor and does not smell uncomfortable. In In addition, silicone is a chemically stable material, and there is no discomfort or allergy to human skin when it comes into contact with the silicone. Silicone mold parts clearly perform better.
The convenience that silicone prototype can bring us is very intuitive. As for TPE, TPR. This is a type of soft material that has been increasingly used in the rubber and plastics industry in the past 10 years. TPE and TPR are environmentally friendly and non-toxic, tested by SGS third-party institutions, TPE | TPR is in line with ROHS, REACH (SVHC), and does not contain toxic phthalate plasticizers, bisphenol A, nonylphenol NP, no Contains polycyclic aromatic hydrocarbons (PAHs) and does not contain toxic phthalate plasticizers, bisphenol A, nonylphenol NP, no Contains polycyclic aromatic hydrocarbons (PAHs) and does not emit an unpleasant odor to the human body. TPE is mild in nature and will not have allergic effects in contact with the skin; TPE meets the ISO10993 biocompatibility test.
2. Soft touch
Both silicone and TPE can provide materials with a suitable hardness to find a balance between facial contact comfort and material strength. At present, the soft rubber TPE and silicone used in gas masks are usually 45~50A. At the same time, both TPE and silicone have Good low-temperature resistance (both can keep soft and elastic at -50℃).
3. One-piece molding
Many times custom customers need to use silicone prototype as a tool. TPE can be directly bonded to the PP material mask by means of injection molding, without the need for adhesives for assembly. This undoubtedly improves production efficiency. The modified silicone that has appeared in recent years can also directly realize the injection bonding of the two materials without the surface pretreatment of PP parts.
We need to look at silicone mold parts rationally, and dialectically analyze their characteristics and uses. Generally, silicone is suitable for high-end gas masks, and TPE is used for low-end products. Because silicone has better tensile resilience than TPE, the tensile strength The deformation resistance of TPE is slightly inferior to that of silicone. Of course, TPE material can be 100% recycled and reused, which is beyond the reach of silicone.
