Introduction
Liquid Silicone Rubber (LSR) is named after its liquid properties and consistency of fluidity. Many people believe that liquid silicone rubber is a new innovation but its development can be traced back to 1944. It was one of the most widely used materials in the medical-beauty industry including facial, chest injections and artificial skin applications. This material was developed by Dow Corning (known as DOWSIL at present) along with products such as Silicone Breast Implants and Silicone Cosmetic Needles.
Properties of LSR
Liquid Silicone Rubber is transparent in nature and has liquid texture. Some of its properties are non-toxic, waterproof, unique fluid form, precision of dimension, etc. Its high transparent texture gives a clear look to the silicone which is an important aspect for the quality of products in fields such as medical and optical. Production of liquid silicone rubber leads to waste minimization due its need to be moulded by the injection process.
Formation of LSR
Liquid Silicone Rubber is formed through the process used to produce plastic injections. This is because of its liquid properties. Following are the moulding steps to form a liquid silicone rubber:
- The raw components are kept at the feeding place of the injecting machine.
- Then those raw components are kept for AB material mixture in the static mixture.
- Then they are injected to the tooling cavity.
- Next, they are heated through the tooling heating process.
- The final step is completion of these parts.
Features of LSR
Below stated are some of the features of Liquid Silicone Rubber:
- High Transparency in its Appearance: The raw components of the liquid silicone are processed in a simple manner without adding any curing agents or other adjuvants. Due to this, it has a transparent and pure texture which can prevent the silicone from external dust and dirt. Thus, liquid silicone rubber can be termed as the purest raw material.
- Automatic Process: The process of liquid injection is automatic. This reduces problems related to quality that are caused by human factors. It also reduces manpower and labour work which leads to improvement in production efficiency and reduces costs.
- High Accuracy in Production: As Liquid Silicone Rubber consists of fluidity; it can flow into every corner of the tooling cavity even if it is closed. Also, there will be no generation of additional burrs because of the silicone rubber injection fed to the closed tooling. In addition to this, computers keep check on the feeding number of raw materials to maintain a control on dimensional tolerance.
- Environmental Friendly: Liquid Silicone Rubber is non-toxic and safe for the environment. The making of this material does not consist of by-products and does not cause any type of environmental pollution which provides protection to the environment.
Difference Between Liquid Silicone Rubber and High-Consistency Rubber
Liquid Silicone Rubber (LSR) is different from High-Consistency Rubber (HCR) in following aspects:
| LSR | HCR |
| Material Processing | |
| ● It consists of 2 components (AB).
● For the process of material vulcanization, Platinum is used as a catalyst. ● It is packed in barrels providing different volume options. ● The raw materials can be directly used in production of parts without any agents or processing after its delivery. |
● It is made up of a single component only.
● Material Vulcanization process is carried out with organic peroxides. ● The raw materials are solidified by gel blocks and packed in cartons. ● The raw materials need to undergo several processes by adding a curing agent after its delivery. |
| Manufacturing Process | |
| ● It is directly fed to the static mixer of the injection machine for mixing the AB components and then injected to closed areas of the tooling cavity. This leads to creation of the parts. | ● It needs to be cut into the correct size according to the final figures, then fed to open tooling. Then the tooling is closed and compressed into a hydraulic moulding machine. |
| Production Techniques | |
| ● The tolerance of the final product is small due the control exercised on the feeding dose of raw materials into the pre-closed tooling.
● It requires a moulding temperature of 130°C. |
● The tolerance of final products is very difficult due to manual processes of cutting and opening-closing of the tooling.
● The minimum temperature for moulding is 180°C. |
| Appearance | |
| ● Transparent in nature.
● No part-line in the final product. ● It needs an injection sprue. |
● Translucent in nature.
● Have an obvious part-line in the final product. ● Do not need an injection sprue. |
| Safety | |
| ● It is processed in a cleanroom, packed in sealed containers and injected in an isolated place. All these processes make LSR a superior material. | ● HCR is slightly inferior to LSR due to less transparency. Also, it becomes difficult for people to check dust or particles due to its surface. |
Uses of Liquid Silicone Rubber
LSR can be applied in the following materials:
- In maternity, nursing and kitchen products.
- Used as sealants in industrial parts such as valves and pipes.
- In commodities that require high transparency such as equipment used for diving, goggles, oxygen masks, etc.
- In medical appliances that require biocompatible features such as diagnostic devices and silicone implants.
- In cosmetic products such as lipsticks and makeup- brushes.
- In the apparel industry for clothes and shoes.
- In instruments that require great precision such as optical products.
Take Away
This is the brief explanation about Liquid Silicone Rubber, its formation, features and uses. The difference between Liquid Silicone Rubber and High-Consistency Rubber is also stated. Please let us know through your valuable feedback and the suggestion in the drop box.