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What is the difference between liquid silicone rubber(LSR) and solid silicone rubber?

Liquid Silicone Rubber is Liquid, Solid silicone rubber is solid and no fluidity. The finished Liquid Silicone Rubber and solid silicone rubber are not easy to distinguish. Liquid silicone rubber finished products has high transparency and odorless with injection feeding mouth, While the finished products of the solid silicone rubber have low transparent.

Solid Silicone Rubber

Solid silicone rubber can be made into all kinds of silicone products after vulcanization. Comparing with the injection molding process, the most advantageous of compression molding is the lower cost. The solid silicone molds are cheaper, and the raw materials are also less expensive. Processing is highly variable, so that, a wide range of different parts can be made with a few basic silicone grades.

But the disadvantage is that the manual operation, the self-demolition mold line has no liquid perfection, and the most softness of the product only reaches about 20 degrees.

How to store the Solid Silicone Rubber

•  Store in closed containers in cool rooms at 0- 30 °C
• Do not expose to direct sunlight
• Keep separate from organic rubber and crosslinker chemicals

Liquid Silicone Rubber

The liquid silicone is liquid. In the production process, the liquid silicone raw material is injected directly into the mold cavity. The process can be fully automated. It does not need to involve a lot of labor. The product is sealed and processed. Therefore, It produces high-quality parts without secondary finishing, and the processing speed is fast. Injection molding is suitable for complex part geometry. Liquid Silicone Rubber is widely in Medical and Baby Care Products.

The disadvantage is that the cost is high, the mold development cost is expensive, and it is uneconomical for the production of small-batch products!

How to store the Liquid Silicone Rubber

•  Store in closed containers in cool rooms at 0 – 30 °C
• Higher average temperatures may shorten the shelf life
• Do not expose to direct sunlight
• When opening the container, make sure that no dirt falls onto the surface of the rubber

We manufacture silicone components with solid silicone rubber and liquid silicone rubber. We will assist you in choosing the right economical material for your projects.

Silicone is becoming more and more popular in our daily lives. But what is the difference between food grade silicone and ordinary silicone? Ordinary silicone is for industrial products, Ordinary silicone is odorous and opaque. While food-grade silicone is widely used for products that are in contact with our food.

What is Food Grade Silicone?

Food grade silicone is non-toxic and odorless, environmentally friendly – contains no BPA, Latex, Lead, Phthalates and biodegradable, long-term use, and other characteristics. Food grade silicone is platinum cured with high elasticity, high transparency, and high tear strength. It meets with the FDA and other environmental requirements. It is safe to contact with food directly.

Food grade silicone is widely application for baby pacifiers, silicone containers, silicone baby bibs, and baby spoons, etc.

How to distinguish Food grade silicone and Ordinary silicone?

food-grade silicone is of better quality and high price than ordinary silicone. Some dishonest manufacturers mix regular silicone in products that are in contact with food. So it is important to know how to distinguish their difference?  Here ukong teaches you a simple way as follows.

1. Pull

Hold the silicone product by hand, focus on one place, and then pull hard on both sides. Turn White is an ordinary silicone, and no white is the food-grade silicone.

2. Smell(Auxiliary method)

If the silicone product pulled white and has a pungent smell, then it can be concluded that it is an ordinary silicone, not food grade. This way is practical and straightforward.

Some food-grade silicone has a slight smell after production, but the odor will disappear after a while.

Food safe silicone is a non-toxic type of silicone that doesn’t contain any chemical fillers or byproducts, making it safe for use with food. All the baby bibs, baby spoons, food containers, and some other baby products are made from only 100% food-grade silicone which is good quality.

Printed Silicone swim caps are best for schools, clubs, colleges, and special events. We custom swimming caps by the screen printing process up to five colors.

Screen printing is a process of pushing ink through a mesh screen in its current state and can pass through this entire screen, so we need to mask off the areas where we don’t want the ink to go through.

If you have areas that are mistakes or stuff you don’t want to print yet, you can use some tape to cover them up. Use painter’s tape and not duct tape — the duct tape will rip off the emulsion.

Now fix your screen set(one screen for each color) line up center and screw in. Layout the silicone caps on a flat surface.

Pour a small amount of silicone ink(Silicone Ink with perfect viscosity and is very easy to work with, and has excellent opacity)horizontally across the top of the screen. Take your squeegee and make one smooth movement down the screen, exerting strong pressure. To do it evenly, it’s best to find some old swim cap to practice on before you try, and then use your new swimming hat for mass printing.

Lift the screen up, pull the swim caps out (Be careful removing the cap as ink is still wet), and you’re done. To make sure the logo sticks on the swim hats for a long time, put caps in the oven on 180 degrees for a few minutes.

Screen printing ink dries too fast, so as soon as you’re done printing swim caps, wash the ink off the screen so you can use it again in the future.  And remember to store the rest ink in the fridge for future printing.

You can customize your swimming hats with your logo printed on both sides. Ukong manufacture plain silicone swim cap, wrinkle-free swim caps, Long hair swim caps and Dome caps with any Pantone colors. We offer the best quality silicone swim caps and printing with a quick turnaround.

What is Liquid Silicone Rubber(LSR)?

Silicone rubber is composite materials, such as RTV Silicone (Room-Temperature-Vulcanizing silicone), the high temperature vulcanized silicone rubber (HTV), High Consistency Rubber(HCR) and Liquid Silicone Rubber(LSR).

Properties of liquid silicone rubber(LSR)

1.High temp resistance

The outstanding property of matter in the condition of high temperature(over 200ºC)for a long time, endure short time exposure up to 350ºC

2.Low temp resistance

Outstanding flexibility in the condition of low temperature(-70ºC). possible to use low-temperature material in the condition of ultralow temperature(under-100ºC）

3.Low compression set

Possible to use application for such as seal ring and gasket due to outstanding compressed permanent strain(strong at shrink and distortion by compress)

4.Chemical resistance

Outstanding oil resistance, solvent resistance, and chemical resistance. Aniline, Alcohol or Alkali cannot be invaded.

5.Electric property

Having hydrophobic for water and excellent electric insulation. No decline of performance by exposure to water.

LSR injection molding advantage

Complex geometries. Provide excellent expressivity of ultra-thin and complicated shape thanks to the low viscosity of LSR.

Automation. Implement automation of the entire process from Dosing to De-molding in contrast with other labor-intensive rubber injection.

Improved safety. Build a safe production area by an unmanned automation system.

Fast cycle. Improve productivity with innovative cycle time by ‘sec.’ unit compared to ‘min.’ unit cycle time of compression and transfer molding

Material preparation. Prevent contamination and faulty mix of material and save time and labor by eliminating the preparation processes like mixing material.

Liquid Silicone Rubber(LSR) application.

Automatic

Wide Applicable Temperature Range: -50~200ºC (-58 ~392ºF)

Maintain of performance required as automotive part under harsh environment.

Stable physical property, Insulation, Weatherability Permanent compression ratio under the wide temperature range

Flexible joint movement and excellent sealing performance.

Silicone reduces noise by creaking, protect and improve the appearance of exterior parts and keep interior parts robustly.

LED

LED is a lighting part made by a compound semiconductor which lights with an electric current.

LSR is applied for encapsulants which protect chip & wire from humidity and external shock. LED package of infrared and visible was used with epoxy encapsulants, silicone encapsulants applied for white and high brightness LED package required for excellent heat, light, yellowing-resisting property.

Why the applicant LSR?

Prevention of light output decrease. Improvement of quality of high performance LED extension of lift time.

Elastomer series. Easy filling for complex shaped parts cracks prevention against stress.

Thermal resistance up to 200ºC. High bright white & blue LED prevents yellowing by UV.

 Medical 

Excellent heat-resisting property. Easy sterilization and autoclave available, no acceleration of bacterial multiplication.

Flexible Silicone Material. No harmful to the patient because it does not contain Phthalate and fabricated additives.

No skin trouble and allergy compared to other lubber products because it is a dwelling type. Widely used in the medical industry like a urethral catheter, especially an oxygen mask, diving equipment.

Mobile

How about “Sealing”?

Ultra-low compression set. Achievement of 15% permanent compression ratio without curing after 22hours at 175ºC.

Wide Range of Hardness. Possible set up a wide range of hardness and achieve the optimized sealing performance.

Excellent media resistance. Superior mass resistibility and strong for corrosion and chemical parts.

How about “Lighting”?

94% Transmission. Approximately 94% uniform transmission over the wide range of visible and invisible light.

<1% Haze. Hazy degree less than 1% after passing through the lens and ensure clarity.

Abbe number. In physics and optics. Abbe number is a measure of the material’s dispersion in relation to the refractive index. The higher abbe number means less light scattering and chromatic aberration. As much more clear reflection.

Durability. High-temperature resistance even above 150ºC. UV light resistance. Micro-crack resistance.

Design Freedom. LSR minimizes stress on complex microstructures based on high flowability. Direct gating through cool runner is available to product required for high tolerance.

LSR application examples

Automotive

Wire seal. It could meet the performance and quality required as the automotive part in a wide temperature range from -50~200ºC（-58~392ºF). It makes joint flexible movement and excellent sealing such as O-ring, Wire seal, Gasket, etc.

Babycare

Pacifier. Excellent heat resistance makes hot water disinfection possible. Harmless to humans without bisphenol-A soft touch like mother’s makes baby snug.

LED Packaging

Led lens. Excellent thermal, light and yellowing resistance. Suitable for high luminance LED applied to the lighting. Automotive, mobile, monitor, TV, Display.

Kitchen Appliances

High thermal and fouling resistance.Ideal for home applications because of harmless to humans.

Industrial

Mask. Soft-touch brings excellent wearing sensation. Suitable in a harsh working environment like welding, painting and dealing chemicals without transformation.

Medical

Menstrual cup. Environmentally friendly material medical grade silicone. No detection of endocrine-disrupting chemicals and chemical substances.

Compression Molding

Compression molding is one form of molded silicone rubber parts. Compressing preformed silicone rubber in a mold with a press during the compression process, Silicone rubber is forced into the mold cavity to form the final product during this process, any excess rubber is pushed into the flash and trim gate allowing easy cleanup once the rubber is set.

Compression molding works best for medium hardness compounds in low volume production. Silicone rubber can be difficult to insert into more complex mold designs. And Soft and Hard silicone rubber compounds don’t do well in the compression molding process.

But Silicone rubber compression molding offers advantages over other methods

• Cost-effective Tooling
• Maximized cavity count
• The short set-up time that saves on short production runs
• Economical process for medium precision
• the least amount of waste in comparison to other molded rubber processes. 

Compression molding can be a cost-effective solution when:

• Having silicone rubber industries manufacture the Tooling.
• the cross-section of the part is very large and requires a long cure time.

Compression molding is used for anything from simple silicone rubber o ring to the most complex silicone parts.

If compression molding isn’t the best fit for your project, Ukong can offer a variety of other molded silicone rubber products through injection or transfer molding.

Injection Molding

Injection molding process involves rapidly injecting an exact amount of Silicone rubber from a tube or cylinder into a closed heated mold, the injection press closes the heated mold and applies pressure to keep the mold closed during the injection and curing cycles, the screw then injects the silicone rubber through the nozzle into the mold. the silicon rubber travels through the mold via a system of runners and sprues and finally enters the mold cavities through a gate, it then fills and packs the cavities to form the desired part rubber.

Injection molding offers economical advantages including:

• short molding cycle
• Lower unit cost
• high dimensional tolerances
• An absence of flash
• little scrap or waste.

If you’re interested in what Ukong can do for your company email us at sales@ukongtech.com

Transfer Molding

Transfer molding combines the advantages of injection molding with the ease of compression molding. the process of transfer molding involves placing a rubber and a chamber at the top of the mold and then pushing through sprues into a heated mold.

Transfer molding offers several advantages over other methods,

• shorter production cycles
• maintains close dimensional tolerances than compression molding
• provides uniformity to the molded products
• fast mode setup.

The Shore Durometer A Scale is an industry-standard for measuring flexible rubber materials, and this is really important in choosing the right mold material for a particular job or in the case of choosing a casting material that might be a flexible casting material.

To get started we need to first understand what is durometer or what the shore A durometer is. The A durometer is both the measurement and the gauge used to measure soft elastomer and what this is a gauge that has a little pin that sticks out at the bottom, and when that pin is pushed in flush with the base of the gauge that’s what gives you the reading on a given flexible material, so depending on how hard how far that pin pushed into the base is determines the hardness or softness of a material. The Shore D Scale measures the hardness of hard rubbers and hard plastics.

Below is a table of shore A hardness scales.

The A scale measures from a zero all the way up to a ninety-five, this is the most common scale for mold making materials. Most flexible rubber materials that you’ll be used for mold making or casting will be found somewhere on the Shore A scale. the low end of the scale a 0 or a 10 is going to be very soft, a high number will be very hard. In fact, the A scale a low number is going to feel very soft almost like human skin, a hard number would feel almost like hard plastic. Most of the materials we use for molding and casting are the lower end of the scale all the way up to the medium. A zero would be about like warm chewing gum, a 10 like human skin, a 50 to 60 would be about like a car tire and a roller skate wheel or a hard hat is going to measure around a 95. 

What materials and durometer can be compression and injection molded? How do you determine what durometer of material to use?

Please remember that the durometer selected will be based on the requirements of your project.

UKONG can help you to choose the material shore hardness for your next silicone project.

How to fold your menstrual cup?

There are different ways that you can fold your menstrual cup. Some methods work better for some bodies and others work better for others. It just depends on your body.

Each fold has it’s own pros and cons but it basically comes down to how small the fold makes the cup and how easily it will pop open once inserted.

Punch down fold. It’s called this because you take your index finger & Push the top down. To the middle of the bottom of the period cup. When you do this it creates a very small insertion point which is quite close to the size of a tampon. It’s also one that we recommend if you’re using a softer cup that has difficulty opening inside. So what you can do is push the base, once it’s inside, and use that to give you a pop at the rim.

 “C” fold. This is very popular & often recommended. You’ll see this in lots of instruction manuals for your new menstrual cup. Take your index finger & push down on the side of the lady cup until one side is touching the other. And then squeeze it together. This is going to make that “C” or “U” shape. This is a very popular fold because you can do it with one finger and you can do it quickly. One thing to note is that, if you’re new, it does tend to open early if you’re not using two hands. And you’re not used to using a cup. The point of insertion is larger than the punch-down fold and some others. However, it is one of the most popular and very easy cup folds.

“7” fold. If the punch down or the “C” fold don’t work for you, you could try the “7” fold. Squeeze the cup and fold one side over. This gives you a fairly small point of insertion at the tip. With some tapering and also gives you control over when you want to push the cup open.

“double 7” fold. Take one side and fold it slightly to the front and take the other side, then fold it slightly down to the back. This gives you that double seven, this is also sometimes referred to as the tulip fold.

Labia Fold. It is great if you’re having trouble getting a softer cup to open. Take the edge of the cup pinch it, push it down to the middle of the cup, and then squeeze sides around this. What you see is a nub from the top of the cup that’s sticking out from the middle. This is what you can use to push on to try and open the cup if it’s stuck.

Triangle Fold. It is very similar to the 7 fold. Squeeze the cup and make it flat. Take one corner and bring it down all the way to the base. This gives you a very narrow point of insertion, similar to the punch down fold, but it’s also quicker and easier to do with your hands. If you’re doing it correctly you should have the shape of a triangle on your cup.

Origami fold, it is similar to the punch down. You want to start with a half punch but then twist it around. This gives it a little bit of a rosebud shape at the top and this also gives you a handy nub that you can use to help open the cup from the bottom.

Diamond fold. To perform the diamond fold you’re going to take one side of the top rim and fold it down on the cup towards the base. Then take the left and right side and roll them inwards until they’re touching. This gives you that flat diamond shape.

The diamond fold is quite large so what most people do is just fold in half, and this is the half diamond fold. You’ve got a much more narrow point of insertion and you also have this great little nub that you can use to pop the cup open when you insert it.

“E” Fold. It is quite impractical. Maybe you want to give it a shot and then little “S” fold. But these are going to be hard to insert because they’re going to want to open at the top.

Using a menstrual cup shouldn’t be this complicated, so we would like you to stick with something a lot more simple. Like the “C” fold or the “U” fold. Very easy, fast and simple. Or the punch down fold.

Whether you’re just trying to protect your hair from the chlorine making you more streamline in the water, or if you wear a cap in open water to be seen easier. Swim caps have lots of uses.

There are 5 different types of materials for swim caps, and each of these caps has a different style to suit all types of swimmers. So let’s take a closer look at some.

Silicone swim caps

silicone are the most popular types of swim caps that are worn by swimmers. Silicone caps are very durable and will last for years as long as you look after it. And a big plus is that they are easy to get on and off.

Latex swim caps

The latex swim cap is great if you want to swim at hotter climates as it’s one of the thinnest caps on the markets, but it will still keep your streamline in the water, and another plus is that latex cap is very affordable.

Rubber swim caps

Rubber swim caps are perfect if you have a latex allergy. They work perfectly in cold waters as they keep your head insulated. And they are very long-lasting.

Lycra swim caps

Lycra swim cap and Spandex swimming caps are extremely durable and last a long time even against chlorine. They are perfect swim caps wear when training or open water swimming as they have great sun protection.

Neoprene swim caps

Neoprene swim hats are a must for any type of open water swimming or triathlon. They work in perfect harmony with troy suits to keep you warm in the colder waters, and they don’t pull your hair. Swim caps pulling your hair when putting on or taking off is a nightmare whether you have long hair or short hair.

Swim caps made from lycra and neoprene won’t pull your hair but if you do love your silicone or rubber caps too much, talcum these silicone or rubber caps, now they won’t sticky.

Traditional fun swim caps

Most swim caps are designed to make you more streamlined in the water, but the more traditional cap isn’t dead. if you’re looking to keep your hair dry and your ears covered or just a cup that is super easy to get on and off, then a traditional swim cap is something you need to consider. Traditional caps can be made from fabrics or rubber, and normally have some classic design. They’re perfect for a leisure swimmer or for aqua aerobics water.

Water temperature is every swimmer needs to think about when buying a new swim cap. Neoprene and Silicone swimming caps tend to be made from thicker materials so they hold the heat for longer. If the pool is 26 degrees or hotter you might overheat, that’s why these types of swim caps are perfect for open water swimmers.

If you are pure pool swimmer then look at the latex caps, they are thinner so you won’t run the risk of overheating in the pool. It’s time for a roundup if you’re looking at a cap for open water swimming, then the neoprene is the right choice for you. It’s thicker so it will keep you warmer for longer in the colder waters.

If you want to be more streamlined in the pool or open water then look at silicone caps they are the industry standard when it comes to competition swimwear.

If you want a cap for fitness and leisure then take a look at getting a lycra or spandex cap, they will keep your hair out of the pool water, and they’re very easy to get on and off. They also last a very long time. They can cover your ears and also they look cool.