More about Silicone products
To Silica Gel is the main raw material processing product, known as silicone products. Silica Gel is a porous material made of Silica Gel which is properly dehydrated. It has an open porous structure and can adsorb many substances. It is a good desiccant, adsorbent, and catalyst carrier. Silica Gel is a granular, glass, porous form of silicon dioxide from synthetic sodium silicate. Silica Gel is tough and laborious; more solid than ordinary household gelatin-like gelatin and Agar. It is a naturally occurring mineral that is refined and processed into any granular or beaded form. As a desiccant, it has an average pore size of 2.4 nm and a strong affinity for water molecules. Silica Gel in daily life is most commonly encountered in a small (generally bead 2 ~ 3 cm) packet. In this form, it is used as a desiccant to control local humidity to prevent damage to some goods or degradation. Since Silica Gel can add chemical indicators and absorb moisture very well, Silica Gel packs usually bear user warnings about not eating the content.
Introduction of Silicone products
To Silica Gel is the main raw material processing product, known as silicone products. Silica Gel is a porous material made of Silica Gel which is properly dehydrated. It has an open porous structure and can adsorb many substances. It is a good desiccant, adsorbent, and catalyst carrier. The adsorption of Silica Gel is mainly physical adsorption, can be recycled and reused. SILICIC GEL can be formed by adding acid to an alkali metal silicate (such as sodium silicate) solution, acidifying it, and then adding a certain amount of electrolyte to stir it. The Silica Gel was left to age for a few hours, then washed with hot water to remove the soluble salts, dried at 60-70 °C, and activated at about 300 °C. The color-changing Silica Gel can be obtained by soaking the Silica Gel in a cobalt chloride solution, then drying and activating the Silica Gel.
Food Grade Silica Gel is non-toxic, tasteless, and insoluble in water and any solvent is a high-activity green product. Food Grade Silicone has inherent thermal stability (- 40 °c-230 °C). For different occasions. The product has good flexibility and satisfies different demands.
Characteristics for silicone products
High-Temperature Resistance: Temperature range-40 to 230 °C, can be used in microwave oven and oven.
EASY TO CLEAN: The silicone product can be cleaned by rinsing with water or in the dishwasher.
Long Life: Silica Gel chemical properties are very stable, and made of products that other materials have a longer life.
Soft and comfortable: Thanks to the softness of silicone material, the cake mold products are comfortable to the touch, extremely flexible, and non-deformable.
Color Diversity: According to the needs of customers, deployment of different beautiful colors.
ENVIRONMENTAL NON-TOXIC: from raw materials into the factory to finished goods not producing any toxic and harmful substances.
Electrical insulation: Silicone Rubber has a very high resistivity, and in a wide range of temperatures and frequency range its resistance can remain stable. 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 parts, and so on.
Low-temperature resistance: the lowest use temperature critical point of ordinary rubber-20 to 30 degrees, while silicone rubber in-60 to 70 degrees still has good flexibility, some special formulas of silicone rubber can withstand very low temperatures, such as a low-temperature sealing ring.
CONDUCTIVITY: When adding conductive filler (such as carbon black), silicone rubber will have good conductive performance, such as keyboard conductive contact points, electric heating components, anti-static components, high-voltage Cable Shields, medical conductive film physiotherapy, etc..
Weather Resistance: ordinary rubber degrades rapidly under the ozone produced by corona discharge, while silicone rubber is not affected by ozone, and its physical properties change only slightly under ultraviolet radiation and other climatic conditions for a long time Such as outdoor use of sealing materials, etc..
Thermal conductivity: When some thermal conductive filler is added, silicone rubber will have good thermal conductivity, such as heat sink, thermal conductive gasket, copier, fax machine thermal roller, etc..
Radiation Resistance: Containing phenyl silicone rubber radiation resistance is greatly improved, such as electrical insulated cables, connectors for nuclear power plants, and so on.
Classification for silicone products
Silica Gel products can be divided into three categories according to the different molding process
Molded silicone
Molded Silicone products are usually through a high-temperature mold in addition to the curing agent of solid Silica Gel after pressure through the curing machine, high-temperature sulfur into solid molding, the hardness of Molded Silica Gel is usually 30 °C-70 °C. According to the Pantone color card, the color of the paste is adjusted. The shape of the mold determines the shape of the molded silicone products, which are widely used in the silicone industry. Mainly used for silicone industry accessories, buttons, silicone products, silicone bracelets, silicone watches, key bags, mobile phone sets, silicone kitchenware, silicone pad, ice lattice, cake mold, and so on.
Extrusion of Silica Gel
EXTRUSION OF SILICONE products is usually through the extrusion machine extrusion of Silica Gel molding, general extrusion of Silica Gel shape is long, tubular can be cut at will, but the shape of the extrusion of Silica Gel has limitations, in medical equipment, food machinery is widely used.
Liquid Silica Gel
Liquid Silica Gel products are injection molded by Silica Gel. The products are soft and hardness can reach 10 °C-40 °C. due to its soft characteristics, it is widely used in simulating human organs, Medical Silica Gel chest pad, etc..
Special silicone Products
Special Silica Gel products are based on the chemical characteristics of Silica Gel or the addition of some auxiliary raw materials, Special Silica Gel products can also have high-temperature resistance (up to 330 degrees) , food-grade (fully in line with the U. S. FDA, LFGB standards), medical-grade, flame retardant grade, by adding auxiliary materials can also have, noctilucent, negative ions, color, and other characteristics.
Purpose
- Silicone products are an integral part of photocopiers, keyboards, electronic dictionaries, remote controls, toys, silicone keys, etc.
2, can be used to do the durable shape of the forming gasket, electronic parts of packaging materials, automotive electronic parts maintenance materials.
3, can be used to make electronic components, molded high point pressure insulators.
4, can be used to make conductive Silica Gel, Medical Silica Gel, Foam Silica Gel, Mold Silica Gel, and so on.
5, for the building and repair of housing, high-speed km joint sealing, sealing of bridges, and other sealing projects.
6, can be used for baby supplies, maternal and infant supplies, baby bottles, bottle protection cover.
7, can be used for kitchen products, kitchenware production, and related auxiliary kitchenware products
8, can be used for medical equipment accessories, because of the characteristics of colorless, tasteless, non-toxic silicone widely used in the medical industry
Influencing factor
Viscosity. Liquid, quasi-liquid, or quasi-solid material flow resistance of the volume characteristics, that is, by external forces when the flow of the internal friction between molecules or flow resistance. Usually, viscosity is proportional to hardness.
Hardness. The local resistance of a material to being pressed into its surface by a hard object is called hardness. Silicone rubber has a 10 to 80 shore hardness range, which gives the designer full freedom to choose the required hardness to best achieve a specific function. A variety of intermediate hardness values can be achieved by mixing polymer substrates, fillers, and additives in different proportions. Similarly, the time and temperature of curing can also change the hardness without damaging other physical properties.
Tensile strength. Tensile strength is the force per unit range required to cause a sample of rubber material to tear. The tensile strength of hot-vulcanized solid silicone rubber ranges from 4.0 MPA to 12.5 MPA. The tensile strength of fluorosilicone rubber ranges from 8.7 MPA to 12.1 MPA. The tensile strength of liquid silicone rubber ranges from 3.6 MPA to 11.0 MPA.
Tear strength. Resistance to the extension of a cut or nick by applying force to a cut specimen. Hot-vulcanized solid silicone rubber is protected from tearing even after being cut and subjected to extremely high torsional stress. The tear strength of hot-vulcanized solid silicone rubber ranges from 9 to 55 KN / M. The tear strength of fluorosilicone rubber ranges from 17.5 Kn / m to 46.4 Kn / M. The tear strength of liquid silicone rubber ranges from 11.5 to 52 KN / M.
Elongation. This is usually referred to as “limit rupture elongation” or the percentage increase in length relative to the original length when the sample is fractured. The general elongation of vulcanized solid silicone rubber ranges from 90% to 1120%. The average elongation of fluorosilicone rubber is between 159 and 699%. The average elongation of liquid silicone rubber is between 220 and 900%. The elongation can be changed greatly by different processing methods and the choice of hardener. The elongation of silicone rubber is closely related to temperature.
Operation Time. The operating time is calculated from the moment the vulcanizing agent is added to the GEL. The operating time and the later curing time are not actually a complete limit. The Gel has been cured of the moment the curing agent is added This operating time means that the product 30 minutes of curing reaction can not affect the quality of the finished product. Therefore, the more time-saving the operation of the product, the more beneficial it is to the finished product.
Curing time. Some would say curing time. That is to say, after such a long time, the vulcanization of Silica Gel is basically over. This basically means that the product is ready to use, but in fact, there is still a very small part of the curing reaction that is not over. So products made with silicone rubber, such as silicone molds, usually sit for a while before being put into use.
Technical parameter
The proportion of vulcanizing agent for Silica Gel. 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. In general, only the weight of the colloid should be considered, and in special cases, the weight of other additives of the Silica Gel should be considered. For example, the use of pad printing silicone vulcanization agent proportion needs to be based on the total weight of silicone and silicone oil added to calculate. C-8e (curing agent) is a transparent, colloidal, environmentally friendly silicone rubber curing agent used for molding silicone products. It is used for transparent, semi-transparent, medium, and high-quality products. It is also suitable for ordinary silicone products.
C-14 food-grade odorless curing agent C-14 is a new odorless curing agent developed by our company, which is used for molding silicone products. Used in medium and high-quality products, especially for the production of Silica Gel Miscellaneous products. Apply to colored parts and transparent, white products, C-14 once after adding sulfur can be odorless. Second vulcanization is better (160 °C; 20 minutes). This product is flammable, when mixing, please add two kilograms of Silica Gel curing agent and an equal proportion of bridging agent to mix well, then quickly add the remaining raw materials to avoid fire.
C-15e environmental curing agent C-15E is a transparent gel-like environmental anti-yellowing curing agent, used for Silicon Rubber Molding vulcanization. It is suitable for medium and high-quality products as well as general silicone processing products. Used for transparent or white parts, it can be cured within four times (or twice within 200 °c baking 1-2 hours), the product does not change yellow.
C-20e anti-yellow curing agent C-20E is a semitransparent silicone rubber anti-yellow curing agent, which is used for molding rubber silicone products. It is suitable for medium and high-quality products as well as general silicone processing products. For transparent or white parts, it can be cured within five times (or within 200 °C for 4 hours), the product will not turn yellow. Applicable to non-ferrous Parts anti-yellow can ensure that non-ferrous parts after multiple curing colors.
H-10 silicone rubber internal demoulding agent this product is a special internal additive for high temperature vulcanized silicone rubber demoulding. It is easy to disperse in addition. This product is widely used in buttons and other complex shapes of silicone products.
Fy-31 silicone rubber finishing agent FY-31 silicone rubber finishing agent is a special primer for silicone rubber back double-sided adhesive, divided into fast-dry and slow-dry type. It is applied to the high-temperature rubber sheet according to the different production processes of the product. The double-sided rubber sheet can be applied to the rubber sheet. This glue is non-toxic and tasteless after drying, and high temperature resistant
Y-21 silicone rubber shrinkage agent this product can reduce the size of silicone rubber products in high-temperature silicone rubber, without affecting other properties of silicone rubber (such as yellowing, mechanical properties). At the same time, this product is easy to add, will not produce white spots, widely used in silicone rubber keys, seals, and other miscellaneous products. Double Ditetrasulfide, good yellow resistance, high product transparency, add less: less spray frost, small smell, suitable for the production of high transparent extrusion products. Mid-range products, suitable for the production of slightly higher transparency requirements of extrusion products. Cheap, low cost, suitable for the production of wire or transparency requirements are not high extrusion products.
Preponderance
Silicone Products Properties:
Superior performance, coupled with the fact that Silica Gel is a non-petroleum product and does not rely on increasingly scarce petroleum resources, makes Silica Gel products become a substitute for similar plastic products has become the general trend, and Silica Gel products can be applied to a lot of plastics Products can not be used in the field, such as baby pacifiers, human organs, and so on, the application prospects are very broad.
Quality factor
First, the quality of Silica Gel will lead to silicone products difficult to remove the edge, POOR QUALITY SILICA GEL raw material its toughness is insufficient, tear strength is also obviously insufficient, in the process of edge removal is certainly very difficult to remove the edge.
Second, the forming process of the product is relatively thick, then burrs are also relatively thick, the increase in thickness must also lead to the difficulty of edge removal.
Three, vulcanization environmental factors, vulcanization temperature to be appropriate, too high and too low problems will lead to difficulty to remove the edge, at the same time vulcanization time also needs to be well controlled, vulcanization time will lead to brittle products Vulcanization time is too short will lead to no effect on the vulcanization link, so the link must be controlled.
Four, the molding mold aspect question, if the mold disassembles the design is not reasonable, the molding mold uses excessively long, the molding mold attrition is serious, the molding mold quality not passes and so on these situations will cause the production after the molding to be difficult to disassemble the edge.
Three factors affecting the disqualification of sanitary and safety testing of Silica Gel products for export
Export, Silicone products’ health, and safety is a high priority in Europe and the United States, this year has repeatedly found that the export of Silicone products pre-inspection and sampling unqualified. The Export Silicone products hygienic index unqualified need our following three aspects reason and carries on the improvement
Poor quality control of raw materials. Some factories pay little attention to the raw materials used for kitchen utensils, and they use low-quality Silica Gel raw materials for the production of food tools without testing the raw materials Or in the production process, the use of substandard color glue and auxiliaries for coloring, resulting in product health unqualified.
The production process is not standard. Because of the particularity of the safety requirement of the Silica Gel tableware, the production technology of the Silica Gel products is very strict. Part of the factory in order to pursue efficiency, the product did not achieve sufficient processing time
Enterprises on the use of product conditions do not pass. Countries such as the European Union require products to be tested according to the strictest use they can foresee. Most factories only according to customer samples of production, the use of products and use conditions do not understand, in dealing with third-party testing is also blind, and even products foreseeable use conditions obviously inconsistent.
Secondary VULCANIZATION OF SILICONE products
Secondary Vulcanization is also called post-vulcanization. Effect of Secondary Vulcanization: When silicone rubber is vulcanized by peroxide, the peroxide breaks down and triggers a reaction of high polymers to produce low-molecular compounds (such as benzene and Benzoic acid) which are present in the rubber and affect its mechanical properties. In addition, the cross-linking density of silicone rubber is not enough after the first stage. The tensile strength, resilience, hardness, swelling degree, density, and thermal stability are all improved. Without Secondary Vulcanization, the properties of Silicone Gel may be affected and no better product can be obtained. The parameters of primary vulcanization and secondary vulcanization may be different, this is related to the actual operation Silicone vulcanization has a variety of high temperatures and room temperature. According to the example of high-temperature Silica Gel, before vulcanization is what we usually call raw rubber, mixing rubber is a lot of additives such as curing agent, mold release agent, and so on with raw rubber. You can tell by the look of it. It breaks when you pull it with your hand. It doesn’t stretch. If the compound is vulcanized at a certain temperature and molded at a certain temperature, the product can be obtained, just like the silicone mobile phone covers we usually see, as long as the manufacturer can provide food certification, it’s usually non-toxic.
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