Liquid silicone rubber(LSR) injection molding

Liquid silicone rubber(LSR) is the preferred material for injection molding.

Why Liquid Silicone Rubber(LSR) is the Material of Choice for Injection Molding?

Liquid silicone rubbers Products

With the development and maturity of the Injection process, liquid silicone rubber(LSR) is the preferred material for injection molding and has been applied in various industries such as electronics, home appliance accessories, maternal and child products, auto parts, power transmission, 3C, and medical. The use of liquid silicone injection molding to create a wide range of precision, near flash-free silicone parts and over-molded components is cost-effective and widely used by manufacturers in numerous industries and applications.

LSR injection molding is to mix the A-barrel silicone rubber containing the catalyst and the B-barrel silicone rubber containing the cross-linking agent according to a ratio of 1:1 and inject it into the mold cavity by injection. Under the action of high temperature and high pressure, a rapid cross-linking reaction occurs and the thermosetting molding process is cured into a silicone product.

Although there are many types of materials suitable for injection molding, LSR has shown many advantages in the injection molding process and has become the first material choice for manufacturing medical devices, infant care products, 3C digital accessories, auto parts, daily necessities, and seals.

Why choose Liquid silicone rubber(LSR) injection molding process?

Liquid silicone rubber injection molding advantages

☉ Due to the low viscosity of LSR, in the LSR injection molding process, even in the case of low injection pressure, the filling flow rate can be faster, and the cavity is filled quickly, but in order to avoid air stagnation, the requirements for mold ventilation are more strict.
☉ The injection molding vulcanization equipment is an injection molding machine. The vulcanization cycle time is short, and it can be completed within 10-30 seconds at a time. The molding cycle does not exceed 1min, which not only saves energy consumption, but also saves manpower and improves production efficiency.
☉ Fully automated, the operator does not need to enter the finished product area. Only a manipulator and a conveyor are required to remove the parts from the injection molding machine, eliminating the risk of scalding for personnel and potential safety hazards during operation.
☉ Using reasonable mold technology and runner design, the injection molding process can realize the bonding of LSR and substrates (thermoplastics such as PC and PEI, as well as glass, metal), thereby greatly improving production efficiency and effectively reducing costs.
☉ The liquid silicone injection molding process is very simple, the products produced are of high precision, and the production process is closed-loop, which can keep the environment clean and hygienic. It is an ideal method for liquid silicone molding.
Building on these properties, LSR inection Molding offer manufacturers the opportunity to cost-effectively mass-produce complex liquid silicone injection-molded parts. Yongrui is an LSR material manufacturer, which can provide customers with injection molding LSR formulations and solutions with high and low viscosity, different colors, and different hardness.

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Liquid silicone rubber injection molding application

Baby care

LSR for baby care is processed by injection molding to obtain the required accessories for mother and baby products. The production process is by pumping the AB component LSR at a ratio of 1:1 to a static mixer, then fully mixing, and then injecting the mixed liquid silicone into the injection molding mold, and demoulding to obtain the required parts.

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Medical

In the field of medical device manufacturing, medical-grade liquid silicone combined with injection molding in a fully enclosed environment and its own special characteristics such as biocompatibility, direct contact with the human body, and high temperature resistance, the produced parts are safer and less allergic. Injection molded medical parts are very durable and can be used normally without melting even at high temperatures of -40~250 degrees. Excellent flexibility, stretches up to 6 times its own length and won't break or break easily. The injection molding LSR materials produced by Yongrui are widely used in ventilator throats, silicone sealing caps, catheters, anesthesia masks, analgesia pumps, input pumps and other parts.

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Medical grade Injection Molding Liquid Silicone Rubber

Optical

Optical clear LSR is produced and processed by injection molding process, from feeding, mixing, injection molding, vulcanization, etc., in a fully enclosed environment to ensure that the processed products are pollution-free and high-precision. The automated production of silicone rubber can be achieved without manual intervention. No assembly is required, high automation is achieved, production costs are minimized, and output is increased.

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Injection molding Self-lubricating Liquid Silicone

Self-lubricating(Oil Bleeding)

Self-lubricating LSR is a new type of liquid silicone suitable for highly automated injection molding processes. After the AB components are mixed, they are vulcanized into a high-resilience oil-permeable elastomer by high-temperature injection molding by an injection molding machine. Silicone oil can be precipitated on the surface, and the silicone oil film can reduce the friction coefficient. In addition, the self-lubricating LSR itself has the characteristics of ultra-low compression deformation, fast oil output, high temperature resistance, etc., which greatly improves the sealing effect of silicone rubber and improves the service life of the finished product. This new type of liquid silicone is suitable for electronics, machinery, automotive, aviation, medical and other fields, such as new energy vehicle cables, automotive wiring harnesses, needle-free valves, waterproof plugs.

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Self-Adhesive

Self-adhesive LSR is a translucent two-component addition LSR, solvent-free and primer-free，It can directly realize the perfect adhesion and vulcanization of LSR and substrate through the injection molding process without assembly. Realize high automation. It has strong adaptability and can be bonded with PC, PPSU, PCTG, glass, and metal materials. Compared with traditional materials using primers, self-adhesive liquid adhesives can reduce the gluing and drying process, reduce production links, greatly improve production efficiency, and improve product yield. It has the advantages of good mold release and fewer burrs and is suitable for two-color injection molding, overmolding, or local bonding of high-precision and complex parts. Widely used in mobile phones, medical, electronic equipment, automobiles, and other parts.

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LSR injection molding material properties and benefits

●Anti-high and low temperature: Compared with traditional cured silicone rubber, it still maintains stable mechanical and electrical properties in the temperature range of -60℃-300℃.
●Environmental safety: It is platinum vulcanization, non-toxic gas when burning, and is a safe food-grade material.
●Radiation and Weather Resistant: Stable and anti-aging in any weather and UV exposure.
●A wide range of application fields: Daily necessities, automotive supplies, industrial supplies, medical industry, food supplies, etc., Can directly contact the human body and food.
●Production method: Fully automated production; short production cycle; materials do not require front-end processing, more efficient and less labor-saving; Curing cycle is extremely short, within tens of seconds, 10 times that of solid silicone rubber.
●High-strength self-adhesive: Good self-adhesion to PPS, PA, PEI, PBT, PC, metal, and other materials, no primer treatment is required before bonding.
●High insulation: The dielectric strength can be greater than or equal to 20kV/mm.

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Why choose YONGRUI liquid silicone rubber for your injection molding material?

Industry experience

Yong Rui has 12 years of experience in the production and development of injection molding LSR.
Solutions

For the technical problems you encounter, we will cooperate with you to connect in real time and provide technical and sample support.
Quality standard

From raw materials to finished products are independent research and development production, quality is stable, through FDA, LFGB certification.
Post-sales service

Reply to your email within 8 hours, and the regular sample delivery time is 3 - 5 days.

How to use injection molding liquid silicone rubber

Tool cleaning

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The tools used to take components A and B must be separated. Or be sure to wipe them clean before each use, to avoid local agglomeration caused by the mixing of the two, which may not be used normally.

Release Agents and Additives

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It is best not to use thermoplastic substrates with internal release agents or "white lubricants" and to avoid additives containing sulfur or amines as they will inhibit the cure of the silicone.

Storage time

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It is recommended to store at 25°C. The safe storage period after the A/B agent is fully mixed is 0.5-3 days (the curing speed is different). The higher the temperature, the shorter the storage time of the liquid silicone.

Cleaning the substrate

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For self-adhesive LSR , because some molds leak oil or the substrate is not handled properly during the transfer process, the substrate is contaminated, so it is recommended to wipe the plastic material with alcohol or white oil before lamination. (White electric oil can be used, lower cost), so as not to affect the bonding effect of self-adhesive special silicone.

Storage Environment

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When you use it, please avoid contact with compounds containing N, S, P, and Sn, otherwise, it will lead to unvulcanization and unsafe vulcanization.

High consistency rubber

RTV-1 Silicone

RTV-2 Silicones

Silicone emulsion

Silicone oil

Silicone Resin