What is food-grade liquid silicone rubber?
Food-grade liquid silicone rubber is a kind of addition-type two-component silica gel, divided into component A and component B. Component A is silica gel, and component B contains platinum catalyst. The entire addition-type two-component liquid silica gel is composed of platinum catalyst, 107 base gum, white carbon black and hydrogen-containing silicone oil. Among them, platinum catalyst is a very important component element. Only with the blessing of platinum catalyst can the two components AB be well solidified and formed.
What is sludge? Sludge is an indispensable auxiliary material in the application and production of silicone molds. Commonly used sludge materials mainly include the following types. One is 60% industrial clay (talcum powder), 30% flexible binder (grease or butter), and 10% solid binder (paraffin or petroleum jelly). The second type is wax 9% to 10%, sulfur 50% to 55%, ash 9% to 10%, grease (butter) 20% to 25%, and a little resin and pigment. The third type is construction sludge, which consists of clay and tung oil.
Sludge is mainly used for handicrafts, hardware, plastic mold making, and student sculptures. It can be recycled and will not deteriorate after being stored for a long time. It is characterized by being sensitive to temperature and can be softened and shaped at low temperatures. The sculptures of handicrafts and other models are extremely malleable.
So can the additive food-grade environmentally friendly silicone come into contact with the sludge? It depends on whether the components of the sludge contain heavy metals and other toxic impurities, that is, whether the sludge can pass food environmental certification. If the sludge contains heavy metals and toxic impurities, once the addition-type silicone comes into contact with the sludge, the contact surface between the food-grade liquid silicone rubber and the sludge will not solidify. The reason is that the platinum in the addition-type food-grade liquid silicone
The gold catalyst is a very active component with extremely strong chemical sensitivity. Once the platinum catalyst comes into contact with toxic substances in the sludge, it will cause the platinum catalyst in the silica gel to fail, thus directly affecting the solidification and molding of the addition food-grade liquid silica gel. .
Advantages of food-grade silicone materials
In many industries, the importance of material selection makes the difference in product quality and performance. Speaking of food-grade silicone material, it has occupied many fields and is widely used in many industries. But many people don’t know what are the advantages of food-grade silica gel compared with other silica gel products? Today Hongtu will analyze the advantages of food-grade silica gel for you.
One of the most important auxiliary materials for food-grade liquid silicone rubber raw materials is silica raw materials, which must first be guaranteed in terms of quality. Many silicone rubber product manufacturers require corresponding test reports before selecting and purchasing raw materials, and whether they will receive corresponding requirements. Silica is one of the most important materials in solid silicone, and its quality determines the performance of the material. Its heat resistance, temperature resistance, tensile strength, etc. are better than ordinary silica, so it is a high-performance material in high-temperature vulcanized silicone rubber and can meet the requirements of food grade, high transparency, and high stretchability.
Fumed silica gel is the heated food grade silica gel product of choice. It plays a major role in silica gel raw materials, because the silicon chain is fine and flexible, the product has high purity, improved hand feel, improved tensile life, and the normal service life is more than twice that of the ordinary precipitation method. Many food-grade silicone products in the market can meet FDA, ROHS and other test certifications and are environmentally friendly and non-toxic.
In the processing process of food-grade liquid silicone rubber product manufacturers, gas phase silicone has certain advantages in the processing and production process. It has strong plasticity and can be mixed more carefully during the rubber refining process. Adding toner and vulcanizing agent can make other The excipients melt more easily and keep the color bright to improve viscosity and fluidity.
Among the raw materials for silicone rubber products, fumed silica is an indispensable reinforcing material in silicone rubber. Due to its unique properties, it has gradually occupied many fields and is widely used in medical, daily necessities, cosmetics, skin care products and other industries.
How to identify food grade silica gel
1. Distinguish from the smell of silicone products
Ordinary silicone smells pungent and has a strong smell. Food-grade silicone is non-toxic and odorless. It has no smell and is an environmentally friendly silicone.
2. Judging from the high temperature resistance of silicone products
Food-grade silicone’s high temperature resistance is generally 250 degrees, and its short-term high temperature resistance can reach about 350 degrees. However, ordinary silicone can only reach a maximum of about 150 degrees.
3. Judging from the stretch degree of silicone
Let’s take a silicone sheet of the same hardness as an example. Take a silicone sheet and stretch it with your hands, and pull it hard with both hands. If it turns white when you pull it and you can smell a pungent smell, it means it is ordinary silicone. On the contrary It is food-grade silicone that does not turn white when pulled and has good stretchability. Sometimes it won’t turn white when pulled. Because the manufacturer produces by-products during the vulcanization process, there will be a light smell. However, it is also food-grade silicone, which will not affect the product quality, and this smell can be eliminated by itself. of.
From the above food-grade silica gel identification methods, we can know that food-grade silica gel generally passes FDA food-grade certification, is non-toxic and tasteless, and has the characteristics of high temperature resistance, high tensile strength, and tear resistance.
Food-grade liquid silicone rubber has a wide range of application fields: it is generally used in the medical industry, electronics industry, baby products, aerospace and aviation industry, automobile industry and some daily necessities, etc. Some common products such as silicone baby pacifiers and silicone tableware are widely used
Food-grade silicone in silicone molds: can be used for automobile parts, military material parts, aerospace material molds, resin handicraft molds, car tire molds, yacht molds, chocolate molds, cake molds, etc.
food-grade liquid silicone rubber in terms of silicone products: can be used to make silicone prostheses, silicone chest patches, silicone masks, silicone dolls, silicone gaskets, adult products, simulated food, simulated dishes, medical-grade products, etc.
Food grade silicone maintenance tips
1. After each use of the silicone mold, you should clean it with hot water (diluted edible detergent) or put it in the dishwasher. Do not use abrasive detergents or foam to clean it. Make sure that the silicone gel is used and stored after each use. It’s all dry before.
2. When baking, the silicone molds should be placed flat on the baking sheet separately. Never dry bake the mold, such as a 6-piece mold. If you only need 3 molds, the other 3 molds must also be filled with water. Otherwise, the mold will be damaged and the service life of the mold will be reduced. In order to ensure that the finished product can achieve a good baking effect, you can lightly spray a small amount of anti-stick baking pan oil on the silicone surface of the mold before baking.
3. When baking is completed, please remove the entire baking tray from the oven and place the baked product on a cooling rack until it cools completely.
4. Silica gel can only be used in ovens, ovens, and microwave ovens. It is strictly prohibited to use gas, open flames, or electricity, or use it directly above the heating plate or below the barbecue.
5. Please do not use knives or other sharp objects on silicone products, and avoid heavy pressure and pulling.
6. Due to static electricity, silicone molds are prone to dust. If not used for a long time, they should be placed in a carton away from direct sunlight.
7. Please do not rinse the silicone mold with cold water immediately after it comes out of the oven to extend its service life.
Things to use when using food silicone raw materials:
1. When using, food-grade silicone raw materials must be fully exposed to the air. The larger the contact area, the faster the curing. On the contrary, the curing will be slower or even non-curing. The thicker the adhesive layer, the longer the vulcanization time. The greater the humidity and the higher the temperature in the same environment, the faster the curing speed of the adhesive layer. The opposite is true.
2. This food-grade silicone raw material product is a non-dangerous chemical and can be stored and transported as non-dangerous goods. When used, it does not cause poison or pollution to the human body and the environment, so there is no need to take too many preventive measures.
3. Products should be kept dry and protected from sunlight and rain during storage and transportation. The effective storage period is 12 months. If it exceeds the storage period, it can still be used after passing the inspection. After using the product, the hose should be tightly capped immediately and can be kept for reuse.
4. First clean the components to be glued to remove oil stains on the surface, then squeeze out the product from the silicone raw material hose and apply it on the surface of the components. When the glue comes into contact with the moisture in the air, it begins to flow from the surface. and gradually solidifies into an elastomer.
What is the mark of food grade silicone?
Generally, food-grade liquid silicone has relevant certificates such as RoSH, SGS, Reach, and MSDS to confirm its safety.
How to identify the quality of food grade silica gel
First of all, look at the appearance. The food-grade silicone liquid made of new and good materials is transparent and bright, and the colloid is also very delicate. The phenomenon shown is that the liquid silicone gel has very good fluidity and is very smooth. The color of liquid silica gel produced from waste rubber cracked materials is yellow and opaque, and the silicone oil layer in the glue is not evenly separated. Poor liquid silicone has obvious lumps and impurities when stirred, and its fluidity is poor.
The second is the smell. Really good food-grade silicone has no smell, is environmentally friendly, non-toxic and tasteless. The liquid silicone produced from cracked materials uses inferior silicone oil and base rubber. This poor material has a certain smell and cannot be completely environmentally friendly, non-toxic and tasteless.
The last step is to look at the effect after curing. After the liquid silicone made from imported raw materials is cured, the surface is very dry and there is no oil or stickiness. After the silicone made from ordinary cracked silicone is cured, especially zero-degree liquid silicone is particularly prone to leakage. Oily and sticky.
Analysis of the reasons why food-grade silicone materials do not solidify
One characteristic of addition-type food-grade silica gel is that when it comes into contact with non-environmentally friendly materials such as sulfur, tin, lead amine, etc., it will be poisoned and will not solidify. The liquid silica gel will form into lumps or solidify. The back surface becomes sticky or cannot be cured at all, resulting in production waste. Therefore, contact with sulfur-containing lead-tinamine substances must be avoided during production, including mixing equipment, containers, etc.
The second reason for non-curing: The AB component must be fully stirred evenly. If not stirred evenly, the glue will not solidify, or the curing will be incomplete, similar to sticky hands.
The third reason: AB component is not added according to the proportion. If component A or component B is added more or less, it will also cause incomplete curing of silicone. Regarding the incomplete curing of addition-type food-grade liquid silicone, The common ones are mainly the above points, and there are many more that you still need to explore slowly by yourself during production.
What are the testing standards for food-grade silica gel?
In terms of performance testing of food-grade silicone addition liquid silicone, it is mainly judged based on the following parameters, including hardness, viscosity, tear strength, tensile strength and elongation. The hardness of food-grade liquid silicone ranges from Shore A0 to 60 degrees, with units every 5 degrees in between. The viscosity of addition-type food-grade silicone is generally below 10,000 cps. As the hardness of the silicone becomes higher, its viscosity will also increase.
Other properties such as tear resistance also change with the change of hardness parameters. The general rule is that the higher the hardness, the worse the performance of silica gel will be; anyway, the lower the hardness, the worse the performance of silica gel will be. The hardness is in the range of 20-30 degrees, and the performance strength of addition-type silicone is the most suitable.
In terms of environmental performance testing of additive food-grade liquid silicone rubber, there are many standards and different methods. First of all, you need to check whether the additive food-grade silicone has a pungent smell. If there is a pungent smell, it is industrial-grade liquid silicone. Secondly, look at the ratio of silica gel. The ratio of addition-type silica gel is mostly 1:1 or 10:1, while the ratio of industrial-grade silica gel is mostly 100:2. The last step is to check whether the addition-type silica gel is prone to poisoning reactions. The main reason is that food-grade silica gel comes into contact with toxic and harmful elements such as heavy metals, which will cause the addition-type liquid silica gel to be poisoned and not solidify.
How to reduce bubbles in food-grade liquid silicone without a vacuum machine?
When food-grade liquid silicone is mixed and stirred, air is mixed into the liquid silicone during the mixing process due to the contact between the liquid silicone and the air, thereby forming bubbles. Too many bubbles will make the molded silicone mold look ugly, and the molded product will also have many pores. Under normal circumstances, we will use a vacuum machine to remove air bubbles, but in the absence of a vacuum machine, how to remove air bubbles from food-grade liquid silicone without a vacuum machine?
If there are only a few bubbles on the surface, it is because the bubbles brought in when the silica gel and curing agent are mixed are not completely eliminated, so when we stir, we need to stir clockwise along the wall of the container. When pouring, we can The liquid silicone flows slowly downward in a filamentous shape, so that the bubbles can be eliminated while pouring the glue. After filling, the bubbles on the surface can be popped with a toothpick.
Food-grade silicone can withstand high temperatures. When encountering a large number of bubbles, we can use a slightly higher temperature to bake the curing agent of the liquid silicone to eliminate impurities, reduce the bubbles, and then use a hair dryer or air gun to blow away the bubbles; of course Also pay attention to whether the mold is for food, such as chocolate molds. You can use an air gun to blow away surface bubbles.
We can also extend the curing time by controlling the ratio of silica gel to curing agent and buy time for the bubbles to naturally discharge. For example, the weight ratio of food-grade silica gel to catalyst is 1:1. We can slightly reduce the catalyst and the two components. The cross-linking reaction is quick-frozen, so that the bubbles in the liquid food-grade silica gel will be slowly discharged upward to reduce the bubbles; you can also negotiate with the food-grade liquid silica gel manufacturer during the ordering process to adjust the operating time to control the elimination of bubbles.
The above-mentioned methods of using toothpicks or sharp air to pop bubbles, or using a hair dryer or air gun to disperse bubbles can only eliminate a little of the bubbles on the surface of food-grade silicone, but it does not ensure that the entire silicone product is bubble-free. If you want to remove the bubbles cleanly, you must use vacuum to remove the bubbles.
Can liquid silicone be disinfected with water? How long is appropriate for disinfection?
Silicone itself is very stable. If it has passed the food grade, it will not change easily. However, you should pay attention to the use environment and try not to use high temperatures above 250 degrees for baking. Food-grade silicone materials have a variety of unique properties. In addition to In addition to high temperature resistance, it can also fully adapt to low temperature environments and climate. In terms of stability, the main components of silicone material are silica, silicone resin and white carbon black. In addition to the catalyst added by the silicone product manufacturer (sulfide agent) will not conflict with any substance, and the catalyst smell can be removed through secondary fluidization and high-temperature baking.
Liquid silicone is an extremely easy-to-clean material and does not require the use of chemicals such as detergent. Furthermore, silicone has good waterproof properties. In addition to pure silicone products, many are made of multi-material metal-plastic composite materials, so it is recommended that the boiling and disinfection time be between 5-15 minutes is more suitable. In addition to boiling in boiling water, the silicone products produced by regular mold silicone manufacturers can also be used in the microwave oven, which is very convenient. However, you must also be careful not to buy fake and shoddy products, otherwise it will be very dangerous. May cause harm to the body.
Generally speaking, regular liquid silicone rubber products can be boiled in boiling water, which can disinfect and sterilize without producing any toxic substances. Food-grade silicone is often formed using liquid silicone after solidification, and its high temperature resistance range is – Between 60℃-230℃, therefore, it can be suitable for direct disinfection by boiling in water.
Application trends of food-grade liquid silicone rubber
According to the report published by Virtue Market Research in 2022, the Global Food Grade Silicone Rubber Market was valued at $976.9 million, and is projected to reach a market size of $1389.25 million by 2030. Over the forecast period of 2023-2030, market is projected to grow at a CAGR of 5.5% .
The global food grade silicone rubber market size was USD 670.78 Million in 2022 and is expected to register a revenue CAGR of 6% over the forecast period, reaching $1.13 billion by 2032.
Food-grade liquid silicone products use the LSR injection molding process (also called liquid silicone injection molding). The two-component or multi-component liquid silicone mixed fluid is pressurized and injected into the heated mold through an injection molding feeder. After curing and molding, it is Production can be completed. Compared with other production processes, the liquid silicone injection molding process has good automation and no waste of raw materials. The injection molded rubber can be fully automated and does not require too much human participation. It can also control manufacturing costs and raw materials.
Food-grade liquid silicone rubber products are also very economical and practical in daily life. Liquid silicone has good tear and wear resistance, and can also be anti-fall and shock-proof. It can be a good substitute for our commonly used fragile items. In addition, liquid silicone products are also soft and skin-friendly, and can well come into contact with human skin without causing adverse reactions. Liquid silicone products also have excellent chemical inertness and can be exposed to a variety of foods and substances without causing changes and material reaction.
According to statistics, the procurement and application volume of liquid silicone in 2018 reached more than 1.6 million tons. The penetration rate of liquid silicone application in various industries will reach more than 40% in 2021. Food-grade liquid silicone will usher in explosive growth in various industries. The food-grade liquid silicone molding process mainly covers consumer electronics such as mobile phones, smart wearables, handheld terminals, connectors, automobiles, medical fields, etc., especially the field of smart terminals will be a new generation of 3-proof process innovation.
Food-grade silicone products are widely used in mechanical products such as coffee pots, water heaters, bread machines, disinfection cabinets, water dispensers, kettles, irons, rice cookers, fryers, pulp machines, and burning appliances. Machinery, electrical appliances, electrical and other industries. Such as: protective covers for water dispensers, coffee pots, beauty salon equipment and lighting products; as well as food replicas, chocolate molds, candy molds, infant comfort toys, food cake molds, various food mats, baby bibs, silicone ice Grids, silicone pacifiers, etc.
Features of food-grade liquid silicone rubberproducts:
High temperature resistance: applicable temperature range -40 to 230 degrees Celsius, can be used in microwave ovens and ovens.
Easy to clean: Silicone products produced from liquid silicone can be cleaned by rinsing with water after use, and can also be cleaned in the dishwasher.
Long life: The chemical properties of silicone materials are very stable, and the products produced have a longer life than other materials.
Soft and comfortable: Thanks to the softness of silicone material, cake mold products are comfortable to touch, relatively flexible, and do not deform.
Various colors: Different beautiful colors can be blended according to customer needs.
Environmentally friendly and non-toxic: No toxic or harmful substances are produced from raw materials entering the factory to finished product shipments.
Insulating properties: Silicone rubber has a high resistivity and its resistance remains 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, etc.
Low temperature resistance: The critical point of ordinary rubber’s operating temperature is -20 degrees to -30 degrees. However, silicone rubber still has good elasticity at -60 degrees to -70 degrees. Some specially formulated silicone rubbers can also withstand higher temperatures. Low temperature, such as low temperature sealing rings, etc.
Conductivity: When conductive fillers (such as carbon black) are added, silicone rubber has good conductive properties, such as keyboard conductive contact points, electric heating element components, antistatic components, high-voltage cable shielding, medical therapy conductive film, etc.
Weather resistance: Ordinary rubber degrades rapidly under the action of ozone generated by corona discharge, while silicone rubber is not affected by ozone, and its physical properties only change slightly when exposed to ultraviolet rays and other climate conditions for a long time, such as those used outdoors. Sealing materials, etc.
Thermal conductivity: When certain thermal conductive fillers are added, silicone rubber has good thermal conductivity, such as heat sinks, thermal seals, copy machines, fax machine thermal rollers, etc.
What are the common problems in using food-grade silicone products?
1. Food-grade liquid silicone rubber tableware
Silicone tableware is easy to use, non-toxic and odorless, and does not release harmful substances. More importantly, it can withstand high-temperature boiling without deformation or wear. However, there are also problems that need to be paid attention to when using silicone tableware:
Foods containing high amounts of acid or grease cannot be served with silicone tableware, because silica gel will react chemically with acid and grease, causing the silica gel to decompose and affecting food safety. Therefore, silicone tableware is best used only to hold harmless foods such as rice and noodles.
When using silicone tableware, be careful to avoid small particles of food, such as rice grains, minced meat, animal bones, etc., because these things will scratch small cracks on the surface of the silicone and affect the performance and safety of the silicone.
Food-grade liquid silicone rubber tableware cannot be heated in the oven or microwave, otherwise it will deform and melt due to excessive temperature.
Food-grade liquid silicone rubber tableware should be cleaned regularly, preferably with warm water and neutral detergent. Scratching tools such as brushes should not be used to prevent the silicone surface from being scratched and affecting safety.
2. Food-grade liquid silicone rubber baking pan
Silicone bakeware is a common product among silicone products. It is not only suitable for baking cakes, bread and other baked goods, but is also widely used in microwave ovens, steam ovens, etc.
Before baking, a layer of cooking oil must be applied to the surface of the silicone baking pan to ensure smooth demoulding of cakes, bread and other foods. But be careful not to apply too much oil, otherwise it will affect the quality and taste of the food.
The griddle can be heated in the oven, but the maximum temperature must not exceed 450℉ and it cannot be used over an open flame or on the grill. In addition, the baking pan should not be exposed to the sun to avoid losing its high temperature resistance, weather resistance and other properties due to excessive exposure.
When heating the silicone baking pan in the microwave, you must check the baking pan for damage and cracks and replace it as soon as possible if necessary. In addition, the time in the microwave oven should not be too long, try to control it within 3 minutes.
3. Food-grade liquid silicone rubber injection mold
Food-grade liquid silicone injection molds are mainly used to make candies, chocolates, cakes and other foods. Because silica gel has good flexibility and is non-toxic and tasteless, it is very popular in the food manufacturing industry. However, there are some issues that need attention during use:
Before using the silicone mold, be sure to clean it with clean water, and then apply a thin layer of oil on the surface to prevent the food from sticking inside. But be careful not to apply too much, so as not to affect the taste of the food.
During use, be careful not to scratch the surface of the mold. If there are scratches on the surface, it will easily absorb stains and make it difficult to clean. Therefore, when using silicone molds, you should use kitchen utensils such as stainless steel shovels that will not scratch the surface of the mold.
Silicone molds cannot be exposed to open flames and high-temperature environments, and they must not be exposed to sunlight to avoid losing elasticity, cracking, and becoming sticky due to high-temperature burning and excessive exposure.
4. food-grade liquid silicone rubber coasters
Food-grade liquid silicone coasters are a kind of tableware used to place cups, water cups, glasses, etc., which not only protect the tabletop, but also prevent the cups from sliding and making them less likely to fall over. However, there are also issues that need to be paid attention to when using silicone coasters:
Food-grade liquid silicone rubber coasters can be cleaned with mild detergent and warm water, and can be temporarily placed on the cleaning table to dry after use. But be careful not to wash it in the dishwasher or use bleach, so as not to affect the quality and life of the silicone.
When using food-grade liquid silicone coasters, avoid dropping the cup heavily on the mat, as this will shorten the service life of the silicone. It is also not advisable to let leaking water from the cup spill onto the silicone coaster to avoid gelatinization and damage to the silicone.
Food-grade liquid silicone rubber coasters should be stored in a cool place in the kitchen to avoid prolonged exposure to sunlight. At the same time, be careful not to stack them during storage to avoid leaving obvious marks and affecting the quality.
