What Are the Different Types of Silicone Parts?

Silicone-based products are called silicone products. Silica gel is a porous substance with different particle sizes, which is formed by the proper dehydration of a silicic acid gel. It has an open porous structure and can absorb many substances. It is a good desiccant, adsorbent and catalyst carrier.

Silicone products

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Silicone-based products are called silicone products. Silica gel is a porous substance with different particle sizes, which is formed by the proper dehydration of a silicic acid gel. It has an open porous structure and can absorb many substances. It is a good desiccant, adsorbent and catalyst carrier. The adsorption of silica gel is mainly physical adsorption, which can be regenerated and reused. Add an acid to an alkali metal silicate (such as sodium silicate) solution to acidify it, and then add a certain amount of electrolyte to stir to form a silicic acid gel; or add an acid or Ammonium salts can also form silicic acid gels. The silicic acid gel is left to stand for several hours to age, and then the soluble salts are washed with hot water, dried at 60 to 70 ° C, and activated at about 300 ° C to obtain silica gel. The silica gel can be obtained by immersing the silicic acid gel in a cobalt chloride solution and then drying and activating the silica gel.

Food-grade silica gel is non-toxic and tasteless, insoluble in water and any solvents, and is a highly active green product. Food-grade silica gel has inherent thermal stability (-40 ° C-230 ° C). It is suitable for different occasions. The product has good flexibility to meet different needs.

High temperature resistance: applicable temperature range -40 to 230 degrees Celsius, can be used in microwave ovens and ovens.

Easy to clean: The silica gel products produced by the silica gel can be cleaned after being rinsed in clean water, and can also be washed in the dishwasher.

Long life: The chemical properties of the silicone material are very stable, and the product made has a longer life than other materials.

Soft and comfortable: Thanks to the softness of the silicone material, the cake mold products are comfortable to the touch, extremely flexible and not deformed.

Diverse colors: different beautiful colors can be formulated according to customer needs.

Environmentally friendly and non-toxic: No toxic or harmful substances are generated from the entry of raw materials to the shipment of finished products.

Electrical insulation performance: Silicone rubber has a very high resistivity, and its resistance value can remain stable over a wide temperature range and frequency range. At the same time, silica gel has good resistance to high-voltage corona discharge and arc discharge, such as high-voltage insulators, TV high-voltage caps, electrical components and so on.

Low temperature resistance: The minimum use temperature of ordinary rubber is -20 to -30 degrees. However, silicone rubber still has good elasticity at -60 to -70 degrees. Some special formula silicone rubber can also withstand Extremely low temperature, such as low temperature seals.

Electrical conductivity: When conductive fillers (such as carbon black) are added, silicone rubber has good conductive properties, such as conductive contact points for keyboards, electric heating element parts, antistatic parts, shields for high-voltage cables, and medical physiotherapy conductive films.

Weather resistance: ordinary rubber is rapidly degraded under the action of ozone generated by corona discharge, while silicone rubber is not affected by ozone, and its physical properties have only slight changes under long-term UV and other climatic conditions, such as those used outdoors Sealing materials, etc.

Thermal conductivity: When some thermally conductive fillers are added, silicone rubber has good thermal conductivity, such as heat sinks, thermally conductive gaskets, copiers, fax machine thermal rollers, etc.

Radiation resistance: The radiation resistance of silicone rubber containing phenyl groups is greatly improved, such as electrical insulation cables, connectors for nuclear power plants, etc.

Silicone products can be divided into three major categories according to the different molding processes

1. Silicone products are indispensable components for making photocopiers, keyboards, electronic dictionaries, remote controls, toys, silicone keys, etc.

2. It can be used to make durable shaped gaskets, packaging materials for electronic parts, and maintenance materials for automotive electronic parts.

3. It can be used to make electronic components and die-press high-pressure edge.

4. It can be used to make conductive silica gel, medical silica gel, foam silica gel, mold silica gel, etc.

5. It is used for construction and repair of houses, seam sealing at high speeds and kilometers, bridge sealing and other sealing projects.

6, can be used for baby products, maternal and infant supplies, baby bottles, bottle protective sleeves.

7, can be used for the production of kitchen products, kitchenware and related auxiliary kitchenware products

8. It can be used for medical device accessories. Because of its colorless, odorless and non-toxic properties, it is widely used in the medical industry.

First, viscosity. Explanation of technical terms: the volumetric properties of liquids, quasi-liquid or quasi-solid substances that resist flow, that is, internal friction or internal resistance between molecules when flowing under the action of external forces. Normally viscosity and hardness are directly proportional.

Second, hardness. The ability of a material to locally resist the intrusion of hard objects into its surface is called hardness. Silicone rubber has a Shore hardness range of 10 to 80, which gives designers full freedom to choose the hardness required to best achieve a specific function. Mixing polymer substrates, fillers and auxiliaries in different proportions can achieve various intermediate hardness values. Similarly, the time and temperature of heat curing can also change the hardness without destroying other physical characteristics.

Third, tensile strength. Tensile strength is the force required to cause a piece of rubber material to tear in each range unit. The tensile strength range of thermally vulcanized solid silicone rubber is between 4.0-12.5MPa. The tensile strength range of fluorosilicone rubber is between 8.7-12.1MPa. The tensile strength of liquid silicone rubber ranges from 3.6-11.0MPa.

Fourth, tear strength. Resistance to enlarging incisions or nicks when applying force on a notched sample. Even after being cut and placed under extremely high torsional stress, the heat-vulcanized solid silicone rubber can not be torn. The tearing strength range of hot sulfurized solid silicone rubber is between 9-55 kN / m. The tear strength of fluorosilicone rubber is between 17.5-46.4 kN / m. The tear strength of liquid silicone rubber ranges from 11.5-52 kN / m.

5. Elongation. Usually refers to "limit elongation at break" or the percentage increase from the original length when the sample broke. Thermally vulcanized solid silicone rubber generally has an elongation in the range of 90 to 1120%. Fluorosilicone rubber generally has an elongation between 159 and 699%. Liquid silicone rubber generally has an elongation between 220 and 900%. Different processing methods and choice of hardeners can greatly change their elongation. The elongation of silicone rubber has a lot to do with temperature.

6. Operating time. The operating time is calculated from the moment the colloid is added to the vulcanizing agent. This operation time and the subsequent vulcanization time are not completely bounded. The colloid has undergone a vulcanization reaction from the moment the vulcanizing agent is added. This operation time means that the product's 30-minute vulcanization reaction can not affect the quality of the finished product. Therefore, the more time saved during product operation, the better for the finished product.

Seven, curing time. In some places it is said to be curing time. In other words, after such a long period of time, the vulcanization reaction of the silica gel has basically ended. This is basically over, which means that the product is ready for use, but in fact, a small part of the curing reaction is not over. Therefore, products made of silicone rubber, such as silicone molds, are usually put into use for a period of time.

Silicone curing agent ratio. Silicone rubber is the most common two-component vulcanized silicone rubber. When not in use, silicone rubber is divided into two parts: colloid and vulcanizing agent. When used, it can be mixed after mixing in a certain proportion. In general, only the weight of the colloid needs to be considered. In special cases, the weight of other additives of the silica gel needs to be considered. For example, the proportion of vulcanizing agent when pad printing silicone is used needs to be calculated based on the total weight of the silicone and the added silicone oil. C-8E (vulcanizing agent) is a transparent gel-like environmental-friendly silicone vulcanizing agent. It is used for the vulcanization molding of silicone rubber products. It is used for transparent, translucent medium and high-quality products. It is also suitable for ordinary silicone processing products.

C-14 food grade odorless vulcanizing agent C-14 is a kind of odorless vulcanizing agent newly developed by our company, which is used for compression vulcanization molding of silicone rubber products. Used in medium and high-quality products, especially suitable for the production of miscellaneous silicone products. It is suitable for colored parts and transparent and white products. It can be tasteless after one time of C-14 sulfurization. Two-stage vulcanization is better (160 ° C; 20 minutes). This product is flammable, please add two kilograms of silicone vulcanizing agent and the same proportion of bridging agent when mixing, and then quickly add the remaining raw materials to avoid fire.

C-15E environmentally friendly vulcanizing agent C-15E is a transparent colloidal environmentally friendly anti-yellowing vulcanizing agent, which is used for the molding and curing of silicone rubber products. Used in medium and high quality products, also suitable for general silicone processing products. It is used for transparent or white parts. It can be guaranteed within four times of vulcanization (or bake for 1-2 hours within 200 ° C), and the product will not turn yellow.

C-20E anti-yellow vulcanizing agent C-20E is a translucent gelatinous anti-yellow vulcanizing agent for silicone rubber products. Used in medium and high quality products, also suitable for general silicone processing products. For transparent or white parts, it can be guaranteed within five times of vulcanization (or bake for about 4 hours within 200 ), and the product will not turn yellow. It is suitable for colored parts to resist yellowing, and it can be guaranteed that colored parts will not change color after vulcanization .

H-10 Silicone Rubber Internal Release Agent This product is an internal additive specially used for the release of high temperature vulcanized silicone rubber. It is easy to disperse when added. Adding a small amount of this product can greatly increase the yield and fully guarantee the quality of the product. This product is widely used in silicone rubber products with complex shapes such as keys.

FY-31 Silicone Rubber Treatment Agent FY-31 Silicone Rubber Surface Treatment Agent is a primer for silicone rubber double-sided adhesive. It is divided into fast-drying and slow-drying types. It is selected based on different production processes of the product, and it is coated on the high-temperature rubber sheet, and then double-sided adhesive is applied to make the double-sided adhesive tightly adhere to the rubber sheet. The glue is non-toxic and tasteless after drying, and resistant to high temperature

Y-21 Silicone Rubber Shrinking Agent This product can be used in high temperature silicone rubber to reduce the size of silicone rubber products without affecting other aspects of silicone rubber properties (such as yellowing, mechanical properties, etc.). At the same time, this product is easy to disperse when added, and will not produce white spots. It is widely used in silicone rubber keys, seals and other miscellaneous products. Double-two-four sulfide has good yellowing resistance, high transparency, and less addition: less frost spray and less odor, suitable for producing highly transparent extruded products. Mid-range products, suitable for producing extruded products with slightly higher transparency requirements. Cheap price and low cost, suitable for producing wires or extruded products with low transparency requirements.

Silicone product performance:

The superior performance, coupled with the fact that silica gel is a non-petroleum product, does not rely on increasingly scarce petroleum resources, makes silica gel products a substitute for similar plastic products. It is a general trend, and silicone products can be applied to many applications where plastic products cannot. Such as baby pacifiers, human organs, etc., the application prospect is very broad.

First, the quality of the silicone raw materials will cause the silicone products to be difficult to remove. The poor quality silicone raw materials have insufficient toughness and tear strength. It is definitely difficult to remove the edges in the process of removing the edges.

Second, in the molding process, the product is relatively thick, so the burr is actually thicker, and the increase in thickness must also cause difficulty in removing the edge.

Third, the vulcanization environment factors, the vulcanization temperature should be appropriate, too high or too low problems will cause difficult to remove the edge, at the same time vulcanization time also needs to be well controlled, too long vulcanization time will cause the product to become brittle, short vulcanization time Will cause the vulcanization link to be ineffective, so the vulcanization link must be well controlled.

Fourth, the molding mold problems, if the mold self-disassembly design is unreasonable, the molding mold is used too long, the molding mold is worn seriously, the molding mold quality is not enough, etc. These conditions will make it difficult to remove the edge after production molding.

Silicone product composition parameters

Three reasons affecting the unqualified sanitary and safety inspection of exported silicone products

The hygiene and safety of exported silicone products is a problem that is highly valued by European and American countries. This year, it has been found that the pre-inspection and sampling of exported silicone products have failed many times. The unqualified sanitary index of exported silicone products requires us to improve the following three reasons

Weak quality control of raw materials. Some factories do not pay much attention to the raw materials used for kitchen utensils. They use low-quality silicone raw materials for the production of food tool products without testing the raw materials, or use unqualified color glue and additives in the production process. Due to coloration, the product is not sanitary.

The production process is not standardized. Due to the special safety requirements of silicone tableware, food silicone products have very strict requirements on the production process. After the product is formed, sufficient time is required to remove volatile substances. In order to pursue efficiency in some factories, the product does not reach enough processing time

Enterprises do not care about product use conditions. The European Union and other countries require product testing to be carried out in the most rigorous use foreseeable. Most factories only produce according to customer samples. They do not know the product's use and conditions of use. They are also blind when dealing with third-party testing, and they are even inconsistent with the foreseeable conditions of use of the products.

Secondary vulcanization of silicone products

Post vulcanization

Silicone products pictures (10 photos)

. The role of secondary vulcanization: When silicone rubber is vulcanized with peroxide, after decomposition of the peroxide triggers the polymer reaction, low-molecular compounds (such as benzene and benzoic acid) are formed in the rubber, which will affect the mechanical properties of the rubber. Moreover, after the silicone rubber is heat-formed in the first stage, its crosslinking density is not sufficient. It is necessary to further vulcanize the silicone rubber to increase its density. The tensile strength, resilience, hardness, swelling degree, density, and thermal stability are all better than once The vulcanization has been greatly improved. If the secondary vulcanization is not performed, the performance of the produced silica gel may be affected to a certain extent, and no better performance products may be obtained. The parameters of the primary vulcanization and the parameters of the secondary vulcanization may be different, which is different from the actual Operational! There are many types of silicone vulcanization, including high temperature and room temperature. Take high-temperature silica gel as an example. Before vulcanization, it is what we usually call raw rubber. Mixing rubber is made by mixing many additives such as vulcanizing agent and release agent with raw rubber. It can be seen from the appearance. It breaks with one hand, without elasticity. If the mixed glue is vulcanized and molded at a certain temperature, the product can be obtained, just like the silicone mobile phone cases we usually see. As for the poison and non-toxic, as long as the manufacturer can provide food certification, generally come They are all non-toxic.