What are the manifestations of defects in Cato liquid silicone gel?
The defects of Cato liquid silicone may manifest in multiple aspects, and the following are some common manifestations:
1、 Incomplete solidification
Performance: The liquid silicone product has not fully solidified, resulting in insufficient hardness or softening of the product.
Possible reason: The vulcanization temperature is too low: Liquid silicone is usually platinum vulcanized, and the vulcanization temperature needs to be between 110 ℃ and 150 ℃. If the temperature is below this range, it will affect the vulcanization effect.
The vulcanization time is too short: Different silicone raw materials and product structures have different vulcanization times, and if the time is insufficient, it cannot be completely cured.
Oil and other pollutants in the injection pipeline or mold can damage the sulfurization structure of liquid silicone.
Uneven mixing of rubber materials: Liquid silicone gel is a two-component A/B agent, which needs to be thoroughly mixed before vulcanization molding.
The rubber material is too cold: the rubber material stored in refrigeration can be used directly, and the low temperature affects curing.
The temperature of embedded materials is too low (for encapsulated products), especially for products with thicker embedded materials. This problem is prone to occur when the workshop temperature is low in winter.
2、 The surface of the product is not familiar or partially unfamiliar
Performance: The surface or local area of the product is not fully matured, presenting a state of incomplete solidification.
Possible reason: Improper use of release agent: Different types of liquid silicone have different requirements for release agent, and using unsuitable release agent can affect the surface curing of the product.
There are grease pollutants on the surface of the mold, such as rust proof oil, machine lubricating oil, or sweat from workers’ fingers.
The embedded objects (plastic/hardware) are contaminated, and the dust, grease, and other dirt accumulated during the production process have not been cleaned thoroughly.
Air pollution: When using pneumatic demolding, the gas inside the air compressor is not clean, which can spray onto the mold and affect the product.
3、 The product has impurities or color spots
Performance: Impurities are mixed in the product or uneven color spots appear.
Possible reasons: The rubber material or mold may be dirty, and impurities may be mixed in during the production process.
The gloves and air gun used by the operator are dirty and have contaminated the product.
The uneven mixing of rubber leads to small white transparent gel particles.
Uneven mixing of colorants or dispersion or precipitation of colorants can affect the uniformity of product color.
4、 Product deformation or shrinkage
Performance: The shape of the product changes or the size shrinks.
Possible reason: The deformation temperature of the embedded object is too low: The vulcanization molding temperature of liquid silicone is high, and if the deformation temperature of the embedded object does not meet the standard, it will deform during the vulcanization process.
Uneven pressure on embedded objects leads to deformation: The embedded objects of silicone encapsulated products are unstable in positioning within the mold, and the sealing position is subjected to uneven force.
Unreasonable product structure design: The shrinkage rate of silicone is generally higher than that of embedded objects (plastic/hardware), and the structure of the silicone part of the encapsulated product should be as uniform as possible, without being too thick or too thin locally.
5、 Product shortage and dents
Performance: There are missing materials or dents on the surface of the product.
Possible reason: Insufficient supply of liquid silicone gel and insufficient injection volume.
The injection port is too small, which affects the filling of the adhesive material.
Poor exhaust, bubbles bursting on the surface of liquid silicone products, causing material shortage.
There are dirt on the surface of the mold, which affects the filling of the rubber material.
6、 The product has bubbles (trapped gas)
Performance: Bubbles appear inside or on the surface of the product.
Possible cause: Poor exhaust: Unreasonable exhaust structure design, resulting in the inability to smoothly discharge bubbles.
Gas in the rubber material: The bubbles generated during the mixing of the rubber material have not been completely removed.
Unreasonable design of injection port: Multiple injection ports may cause bubbles to accumulate in the adhesive material.
In summary, the defects of Cato liquid silicone may involve multiple aspects such as solidification, surface curing, impurities, deformation, material shortage, and bubbles. To avoid the occurrence of these defects, it is necessary to strictly control various process parameters and raw material quality during the production process, and strengthen quality inspection and control.
