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Fluorosilicone

Fluorosilicone is a good elastomer. The main chain is Si-O bond in its structure. After adding polar fluorine atoms (such as trifluoropropyl) into the side chain, the structure of fluorosilicone rubber is called CH2CH2CF3. Because of the strong electron-absorbing effect of fluorine atoms, the bond length of the C-F bond is shorter, it can form a good shielding effect to C-C bond, improve oil resistance and solvent-resistance of rubber, and make it a good elastomer with good resistance to non-polar medium at -68°C ~ 232°C. Therefore, fluorosilicone rubber is widely used in the field of the high-end locomotive and military aerospace seals.

As the price is expensive, and the electronic effect of fluorosilicone rubber, has strong adsorption to the surrounding dust, thus affecting the performance, so the production process of fluorosilicone rubber is very strict. Here is some suggestion of the production process.

Transportation and preservation. In the process of preservation and transportation, fluorosilicone rubber must be wrapped with insulating paper and plastic bags to prevent dust and impurities from contact with the rubber and adsorption.

Cutting fluorosilicone rubber. In the process of taking materials, cutting. First of all, using alcohol to scrub the surface of the knife or the tool scissors, after cleaning, can start the cutting. In the cutting process, try to avoid hand, skin, and rubber contact, but can not wear gloves, so as to avoid the pollution of glove fiber or skin oil on the fluorosilicone rubber.

Weighing fluorosilicone rubber. Before weighing, the tray needs to be cleaned with alcohol.

Fluorine silicone rubber mixing. Before mixing, must use alcohol scrub the mixer roller and baffle, to ensure no impurities contamination. When mixing, should pay attention to the roller temperature, when the roller temperature is 18 °C ~ 28 °C mixing process performance is better. If you need to add silica to adjust the hardness, you must first use hydroxyl fluorine silicone oil to pretreat the silica.

Vulcanization of fluorosilicone rubber. The mold used to produce fluoroelastomer products must be treated by surface treatment, chrome plating treatment, if necessary, use the external release agent.

Second vulcanization of fluorosilicone rubber. There is a lot of low molecular weight volatiles after the first vulcanization. Long-term use will affect the properties of the products, so the general products must be vulcanised in two stages. the second stage vulcanization is carried out in the electric heating blower, and the temperature is kept constant after the required temperature is reached by the way of step-by-step heating. For normal fluorosilicone rubber products, the temperature is 200℃ with 4 to 6 hours.

Re-mixing of fluorosilicone rubber. Long-term parking of fluorosilicone rubber easy structuralization, affect the performance, so for the use of long-term parking of rubber materials need to be re-mixing, placed in the mixer roll 25 times, mixing time of about 8 minutes, to ensure that materials mixed evenly.

Fluorosilicone rubber production environment.  Because it has the characteristic of static electricity absorption ash, so the production environment needs to be purified and dust-free workshop, the production tool is the special equipment. Workers are required to wear clean clothes and hats for entry and exit operations.

rubber molding

Silicone is a thermosetting elastomer, with the advantages of safety and non-toxic. TPE meaning a Thermoplastic Elastomer material. It can be recycled and processed by injection molding. TPU is called Thermoplastic polyurethane elastomer. PVC is polyvinyl chloride, is the world’s largest production of common material, applications widely. Rubber there are many types of rubber, such as natural rubber, cis-1, butadiene-styrene rubber, propylene rubber, and of course silicone rubber.

Mobile phone cover, gloves, waterproof rings, toothbrush handles, various wheels, and sexy doll, etc. are made from soft material, but these materials used are different. What is the difference? how to choose the correct material? First of all, we need to consider the performance of the materials and what they used for. The main properties of soft material are hardness, elasticity, corrosion resistance, weather resistance, coefficient of friction, cracking, coloring, high (low) temperature resistance, cost, processing technology, etc. If used in daily necessities, baby products, etc. we need to pay attention to whether harmful to the human body, whether there is a bad smell, feel comfortable and other factors. Special circumstances also need to consider conductive performance (such as silica gel added conductive carbon can be made of silicone keypads), thermal conductivity, radiation resistance, light transmission performance.

TPE

TPE is Thermoplastic Elastomer, which is a Thermoplastic Elastomer material. Thermoplastic means it can be recycled and processed by injection molding. TPE products have excellent coloring, environmental protection, and non-toxic. Can be secondary injection molding, and PP, PE, PC, PS, ABS, and other matrix material coating adhesion, can also be molded alone.

TPE secondary injection molding handle
TPE secondary injection molding handle

The heat resistance of TPE is not as good as that of rubber. With the increase of temperature, the physical properties of TPE decrease greatly, so its application is limited. At the same time, compression deformation, elastic recovery, durability is relatively poor than rubber. The price is also higher than rubber.

TPE material has a wide range of hardness, excellent transparency, gloss, and comfortable feel, widely used in adult products. With good UV resistance, weather resistance, high temperature resistance, long-term use in outdoor.

TPU

TPU (Thermoplastic polyurethanes) is called Thermoplastic polyurethane elastomer, the hardness range of TPE is from 60A to 70D of s shore hardness (now has soft TPU with a hardness of 45A around, but its price is very expensive), while the hardness range of TPE can be chosen from shore hardness scale 0 to 100 of shore hardness. Therefore, the TPE hardness ranges are medium-low hardness, while TPU hardness is medium-high hardness.

TPU is superior to TPE in elasticity and elastic recovery (flexure creep resistance). TPU main material is a polymer homogeneous structure, which belongs to the polymer resin. While TPE is a multi-component blend of multi-phase structure aggregation of alloy materials. TPE with high hardness is easy to deform, and TPU shows good elasticity in all hardness ranges, and the products are not easy to deform.

TPU spring wire
TPU spring wire

Some coated molded products, such as handles, wheels, maybe TPE or TPU. TPU material products, feel more roughly, friction resistance, while TPE material products feel more smooth and soft, friction is weak.

PVC 

PVC is polyvinyl chloride, was the world’s largest production of common material, applications are wide. It should be noted that, on October 27, 2017, The Who’s International Agency for Research on Cancer published a preliminary list of carcinogens, polyvinyl chloride, in the list of 3 carcinogens.

PVC itself is a hard material, but with the addition of a plasticizer, can make the products soft, easy to bend, fold, with elasticity. Such as PVC sheet, PVC panel, etc.

PVC keychain
PVC keychain

From the outside, the PVC product is coarser than the silica gel product, and the surface of the silicone product is smooth and colored. Judging by the hand feeling, the silica gel product quality is soft, toughness and elasticity are good, PVC soft glue is relatively hard. The soft and hardness of PVC and Silicone can be adjusted, but PVC no toughness.

There are common PVC materials and environmental PVC materials also known as ATBC-PVC. While silicone can pass the ROHS test, is environmentally friendly. Silicone products are generally made more transparent, burning smell slightly. After burning, PVC products will be black, smelly. Silicone products are more heat-resistant and cold-resistant, silicone products can be heated in the microwave oven, and PVC not.

Silicone

Silicone is a thermosetting elastomer, with the advantages of safety and non-toxic, insoluble in water and solvent, non-toxic tasteless, chemical property stability, no reaction with any material, high adsorption performance except strong alkali, hydrofluoric acid, good thermal stability, chemical property stability, the first widely used in medical products, food products, baby products, sports products, such as silicone bibs, menstrual cup, silicone caps, baby suction bowl, etc.

silicone baby bowl

The processing of silicone products is complex, which needs a series of processes such as mixing, molding and vulcanized, etc. Silicone products are thermosetting rubber, after vulcanization when reheating silicone products will not melt. But silicone items can not be directly recycled reprocessing. Silicone products are generally more expensive than TPE products.

Silicone general shore hardness is 0A to 80A, and TPE general hardness in 0A-100A, the softest can reach 000 degrees or 0000 degrees, so TPE softer,

Silica gel has advantages over TPE in high-temperature resistance. Silica gel temperature in general between 200 degrees to 300 degrees. While TPE theory generally temperature between 130-150 degrees, and higher temperature, it will be aging cracking.

Silicone prices are higher than TPE prices except for the special TPE materials, such as halogen-free flame retardant, food-grade, and so on.

Rubber

There are many types of rubber, such as natural rubber, cis-1, butadiene-styrene rubber, propylene rubber, and of course silicone rubber; Silicone is one of the specific types of rubber, which is short for silicone rubber.

Silicone and rubber are two materials, we can use both under the same environment, but with the change of physical environment and requirements, the performance of the two materials will have a significant difference, but it takes time to manifest. For example, the most commonly used laboratory condensers, there are rubber and silicone, but silicone properties better, the anti-aging effect is significant. In structure, the main chain of rubber is mainly carbon, it is organic, while the main chain of silicone is mainly a Si-O bond, which is the main difference between them.

The coloring of silica gel is rich, can be made into a variety of different colors, rubber products are mostly black, occasionally can see other colors. For example, bicycle tires occasionally have other colors, and car tires are black. The reason is that the process of mixing rubber with carbon black and high-temperature condensation of carbon and hydrocarbon can make rubber very strong, wear-resistance, and anti-aging greatly improved. Rubber price is cheaper than silicone. Rubber molding is almost the same as the silicone molding process. Rubber is more widely used in industry, such as rubber coupling, rubber stoppers, rubber sleeve, rubber buffer, rubber fender, etc.

custom rubber products
Custom rubber products

Silikon shore hardness

There are two most common Durometer scale, Shore A for flexible elastomers(range in hardness from very soft to medium, and to hard with almost no flexibility at all.) and Shore D for hard elastomers(hard rubbers, hard plastics). Before producing silicone items, It is very important to select the correct shore hardness of liquid silicone for different applications.

Shore A 0-degree application: it can be used for filling mould of super-soft silicone rubber mold, making of imitation prosthesis, such as mask, penis, sex articles, silicone rubber sheet, making of the soft gasket.

Shore A 5-degree application: it can be used for filling mold of super soft silica gel mould, making hand-made soap and candle silica gel mould, making imitation prosthesis products, such as mask, penis, sex articles, and silica gel sheet, making soft gasket products.

Shore A 10-degree application: can be used for soft silica gel mold filling mold production; hand soap, candle silica gel mold production; simulation of the production of prosthetic products, such as silica gel hands, feet, masks, penis, sex products, silica gel sheet, and soft gasket production.

Shore A 15-degree application: can be used for soft silicone mold filling mold production; hand soap, candle silicone mold production; simulation of the production of prosthetic products, such as silicone hand, foot, mask, penis, sex products, silicone skin, and soft gasket production.

Shore A 20-degree application: can be used for food-grade candy chocolate mold or single mold manufacturing; epoxy, polyester resin, polystyrene, vinyl plastic, paraffin wax, and other materials mold; Small cement components, cultural stone, concrete, gypsum, and other products of mold manufacturing; 3d printing mold production, candle manual soap pouring mold production; mechanical properties of waterproof sealing use.

Shore A 25-degree application: can be used for food-grade candy chocolate mold or single mold manufacturing; epoxy, polyester resin, polystyrene, vinyl plastic, paraffin wax, and other materials mold; Small and medium-sized cement components, cultural stone, concrete, gypsum, and other products of mold manufacturing; 3D printing model production, candle manual soap pouring mold production.

Shore A 30-degree application: can be used for metal crafts, alloy car and other precision mold manufacturing; epoxy, polyester resin, polystyrene, vinyl plastic, paraffin, and other materials mold; Large cement components, cultural stone, concrete, gypsum, and other products of mold manufacturing; high-precision hand plate model design, rapid prototyping design; used in vacuum bag multi-mold spraying class production.

Shore A 40-degree application: can be used for metal crafts, alloy car, and other precision mold manufacturing, as well as fixture protection; epoxy, polyester resin, polystyrene, vinyl plastic, paraffin, and other materials mold; Large cement components, cultural stone, concrete, gypsum, and other products of mold manufacturing; high-precision hand plate model design, rapid prototyping design; lost wax casting process of silicone mold production; product measurement reference production.

Shore A 50-60 degree application: can be used for metal crafts, alloy car, and other precision mold manufacturing, as well as fixture protection; epoxy, polyester resin, polystyrene, vinyl plastic, paraffin, and other materials mold; Large cement components, cultural stone, concrete, gypsum, and other products mold manufacturing; high-precision hand plate model design, rapid prototyping design; product measurement reference production.

The hardness described above is only for the most extensive use. For special uses, it is important to know the part or product that you will be molding clearly.

Lfgb Fda silicone

LFGB (Lebensmittel-, Bedarfsgegenstände-und Futtermittelgesetzbuch, or “ “food, tobacco products cosmetics and other commodity management laws”), is the most important basic legal document in German food hygiene management. The specific LFGB standard: German Food, Articles of Daily Use and Feed Code of September 1, 2005 (LFGB), Section 30 & 31 with amendments and Regulation (EC) No 1935/2004 of the European Parliament and of the Council of 27 October 2004.

LFGB test requested, including extractable components, sensorial examination odour and taste test, Lead and Cadmium, Volatile organic matter(VOM) and Polycyclic aromatic hydrocarbons(PAHs) Content.

Test RequestedConclusion
German Food, Articles of Daily Use and Feed Code of September 1,2005(LFGB), Section 30 & 31 with amendments and BfR recommendation -Extractable ComponentsPASS
German Food, Articles of Daily Use and Feed Code of September 1,2005(LFGB), Section 30 & 31 with amendments-Sensorial examination odour and taste testPASS
German Food, Articles of Daily Use and Feed Code of September 1,2005(LFGB), Section 30 & 31 with amendments and BfR recommendation -Lead and CadmiumPASS
German Food, Articles of Daily Use and Feed Code of September 1,2005(LFGB), Section 30 & 31 with amendments and BfR recommendation -Volatile organic matter(VOM)PASS
Polycyclic aromatic hydrocarbons (PAHs) ContentPASS

German Food, Articles of Daily Use and Feed Code of September 1,2005(LFGB), Section 30 & 31 with amendments and BfR recommendation -Extractable Components

Test Method:    With reference to 61. Mitteilung über die Untersuchung von Kunststoffen, Bundesgesundheitsbl 46 (2003) 362.

Simulant UsedTimeTemperatureMax.Permissible LimitResult of 001Comment
Distilled Water4.0hr(s)100℃0.5%(w/w)<0.1%(w/w)PASS
3% Acetic Acid (W/V) Aqueous Solution4.0hr(s)100℃0.5%(w/w)<0.1%(w/w)PASS
10% Ethanol (V/V) Aqueous Solution4.0hr(s)100℃0.5%(w/w)<0.1%(w/w)PASS

Notes: %w/w = percentage of weight by weight

German Food, Articles of Daily Use and Feed Code of September 1, 2005 (LFGB), Section 30 & 31 with amendments-Sensorial examination odour and taste test

Test Method:    With reference to DIN10955:2004, direct contact method.               No.of panelist:6

Test Item(s)Limit001
Test mediaDistilled water
Test Temperature (℃)100
Test time (hr)4
Sensorial examination odour (Point scale)2.51.0
Sensorial examination taste (Point scale)2.51.0
Comments  PASS

Notes: Intensity scale(rounded at 0.5): 0 – no perceptible difference, 1 -just perceptible difference, 2 -slight difference, 3 -marked difference, 4 -strong difference

German Food, Articles of Daily Use and Feed Code of September 1,2005(LFGB), Section 30 & 31 with amendments and BfR recommendation -Lead and Cadmium

Test Method:     Microwave digestion (GZTC CHEM- TOP-004-01), analysis was performed by ICP-OES.

Test Items(s)LimitUnitMDL001
Cadmium (Cd)mg/kg2ND
Comment   PASS
Lead (Pb)mg/kg2ND
Comment   PASS

Notes: 1.mg/kg =milligram per kilogram of sample  2.MDL=Method Detection Limit  3.ND=Not Detected(less than MDL)  4.★=Absent

German Food, Articles of Daily Use and Feed Code of September 1,2005(LFGB), Section 30 & 31 with amendments and BfR recommendation -Volatile organic matter(VOM)

Test Method:    With reference to 61. Mitteilung über die Untersuchung von Kunststoffen, Bundesgesundheitsbl 46 (2003) 362.

Test Items(s)LimitUnitMDL001
Test Temperature200
Test Timehr(s)4.0
Volatile organic matter (VOM)0.5%(w/w)0.1ND
Comment   PASS

Notes: 1. %w/w = percentage of weight by weight  2.MDL=Method Detection Limit 3.ND=Not Detected(less than MDL)

Polycyclic aromatic hydrocarbons (PAHs) Content

Test Method:   With reference to AfPS GS 2014:01 PAK, analysis was performed by GC-MS.

Test Item(s): Sum of 18 PAHs. Sum of 7 PAHs Acenaphthylene, Acenaphthene, Fluorene, Phenanthrene, Pyrene, Anthracene, Fluoranthene. Naphthalene(NAP CAS NO. 91-20-3). Acenaphthylene(ANY, CAS NO.208-96-8). Acenaphthene(ANA, CAS NO.83-32-9). Fluorene(FLU, CAS NO.86-73-7). Phenanthrene(PHE, CAS NO.85-01-8). Anthracene(ANT, CAS NO.120-12-7). Fluoranthene(FLT, CAS NO.206-44-0). Pyrene(PYR, CAS NO.129-00-0). Benzo(a)anthracene(BaA, CAS NO.56-55-3). Chrysene(CHR, CAS NO. 218-01-9). Benzo(b)fluoranthene(BbF, CAS NO.205-99-2). Benzo(j)fluoranthene(BjF, CAS NO.205-82-3). Benzo(k)fluoranthene(BkF, CAS NO.207-08-9). Benzo(a)pyrene(BaP, CAS NO.50-32-8). Benzo(e)pyrene(BeP, CAS NO.192-97-2). Indeno( 1,2,3-c,d)pyrene(IPY, CAS NO.193-39-5). Dibenzo(a,h)anthracene(DBA, CAS NO.53-70-3). Benzo(g,h,i)perylene(BPE, CAS NO.191-24-2)

FDA testing (Food & Drug Administration Standard) is the minimum safety standard for food-contact silicone products in the US & Australia. The specific standards is: United States Federal Code, Part 21, Food and Drugs (21 CFR).

FDA test requested

Test RequestedConclusion
FDA 21 CFR 177.2600-Total extractive residuesPASS

FDA21 CFR 177.2600-Total extractive residues

Test Method:     With reference to US FDA 21 CFR 177.2600.

Simulant UsedTimeTemperatureMax.Permissible LimitResult of 002Comment
Distilled Water7.0hr(s)Reflux temperature20mg/sq.in<0.5mg/sq.inPASS
Succeeding Extraction2.0hr(s)Reflux temperature1mg/sq.in<0.5mg/sq.inPASS
n-Hexane7.0hr(s)Reflux temperature175mg/sq.in9.2mg/sq.inPASS
Succeeding Extraction2.0hr(s)Reflux temperature4mg/sq.in<0.5mg/sq.inPASS

In summary…

LFGB silicone pass more strict testing and is therefore more expensive, while FDA silicone is more widely used, but silicone that has passed LFGB testing is definitely safer.

Different countries have different standards for food-contact silicone products. LFGB is standard mainly for Europe, while FDA (Food and Drug Administration) is standard in America(though different country has their own FDA standard, but US FDA is internationally applied.) 

Our baby suction bowls, Baby self-feeding spoon, Silicone Baby Plate, Silicone teether, and other silicone baby items are produced with LFGB silicone. We also can custom products with FDA approved silicone or silicone with LFGB certification based on customer’s requirement.

swim caps print logo

There are many different printing processes on silicone products. silicone silk screen printing, silicone printing, silicone color printing, silicone transfer printing, silicone film printing.

Silicone silkscreen printing

swim caps print logo

The silkscreen is the first printing method. Screen printing requires a logo screen set. Generally, the silk screen printing ink will be thicker and brighter, and the printed pattern has a strong dimensional sense. Silkscreen printing can also print thin lines and is also suitable for large-area printing. The disadvantage is that it is low efficiency as by hand printing and only can up to print 5colors. Silkscreen can only print one color at a time, bake it. Then fix another logo screen set to print the second color.

Silicone pad printing

pad printing

It is printed by machine with a metal plate. The plate is flat, with the image chemically imprinted. The silicone pad is pressed onto the ink, picking up the image. And then the silicone pad is pressed onto the substrate, transferring the image on the silicone product.

The advantage of pad printing is that the printing speed is fast, and you can print several colors at the same time. Pad printing can be used on a variety of substrates, particularly oddly shaped objects that are difficult to screen print. The disadvantage is that the ink is slightly thinner than the silkscreen, not too bright.

Silicone color printing

CMYK printing

color printing is also called digital printing, CMYK printing. The technique used to print full-color images. The silicone ink and the silica gel itself are chemically reacted with each other, so the based product should be white. Otherwise, the logo will be discolored. If the based products in different colors, it is better to print with white ink by silkscreen printing or pad printing first, then do the CMYK printing. However, because there is dust in the printing process, when there is color printing, there will be small dust particles on the surface.

Silicone heat transfer printing

Your custom logo is printed on transfer label or film first, and then ink is thermally transferred from the label to the silicone products using heat by press machine. It can print several color logo. But the logo screen is expensive.

Silicone water transfer printing

water transfer printing

Firstly put the printed water-soluble film on the surface of the water. Immerse the silicone products into the water, the upward pressure of the water causes the ink to wrap and adhere to the item. Then removed the products from the water. It can be applied to all types of substrates with full colors printing.

Silicone film printing

kid swim caps

Cover the film on the silicone while compressing the product, without secondary processing and printing. Washable, folding, scratch-resistant grade A, dry-wearing and wet-resistant grinding A grade, excellent color printing pattern, clear and vivid color printing pattern, environmental protection

Ukong can do the above all kind of silicone printing. We carefully evaluated all methods and help you choose the right way to print your silicone products.

Liquid silicone rubber overmolding

TPE over-molding widely used in the thermoplastic elastomer industry. In recent years, with the rise of liquid silicone applications and the excellent properties of liquid silicone rubber materials, TPE over-molding products are gradually being replaced by liquid silicone rubber. The liquid silicone rubber has excellent comprehensive performance. LSR has high-temperature resistance than thermoplastics, soft-touch, high quality of materials meet with the medical-grade requirements. It is the best soft material for over-molding and injection molding and two-color injection molding.

Silicone over-molding is a process that is used to cover, bond, or encapsulate an existing part with silicone material.

Liquid silicone rubber overmolding silicone overmolding

 

The main advantages of liquid silicone over-molding

The liquid silicone rubber(LSR) material has excellent slip resistance and soft elastic touch, which can improve the touch feeling of the product and enhance the grip.

liquid silicone rubber has different hardness range Shore 10-90A according to the physical properties of the product, as well as suitable physical properties (such as abrasion resistance, adhesion, melt index, etc.). A variety of possible material application options are available for different products.

Liquid silicone rubber is an environmentally friendly raw material. It does not contain phthalates, halogens, and does not include 38 SVHC substances of REACH. It meets the environmental testing standards of ROHS, REACH, NP, EN71, and PAHS, and can fully meet the environmental protection requirements.

 

Liquid silicone rubber over-molding processing technology

Silicone rubber over-mold injection molding process involves two steps wherein a completed plastic or metal entity is placed into the mold site of an LSR mold, after which the LSR is over-molded directly onto the part.

The injection molding temperature is different depending on the hard material. The commonly plastic substrate is PC or PA, and aluminum alloy can also be over-molded by liquid silicone rubber.

 

Common problems and solutions for liquid silicone rubber over-molding processing

1) Lack of silicone – the product is trapped air, or the silicone is not enough.

2) blunt, overflow edge – increase the clamping force; reduce the injection pressure.

3) Poor viscosity – choose the right adhesive. Check the plastic or metal substrate is clean.

4) out of shape during Injection molding – lowering the molding temperature; using a high-temperature resistant substrate.

 

Ukong is a liquid silicone product OEM/ODM manufacturer. We are committed to the development of new processes for liquid silicone (LSR) products and custom products. We have advanced molding techniques such as the high speed of injection molding, short vulcanization time, automatic, self-removing, and no burrs.

Our products including the liquid silicone rubber baby care, medical liquid silicone products, mobile phone 3C waterproof accessories, automotive electronic accessories, liquid silicone kitchen products, industrial sealed liquid silicone Products, etc. and has rich experience in the liquid silicone rubber over-molding parts. (liquid silicone rubber to plastic, liquid silicone rubber to metals, liquid silicone rubber to glass or ceramic, silicone two-color products)

 

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

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

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.

silicone container silicone spoon

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.

food grade silicone

  1. 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.

silk screen printing

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.

Printed swim caps

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.

swim caps print logo

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.