Are you still confused about whether to use silicone sealant or acrylic sealant for your project or machine? Are you experiencing financial losses due to the rapid failure of old sealants and looking for an alternative? This guide will compare these two types of sealants in detail and help you make a better choice.
What Is Silicone Sealant
The main component of silicone sealant, or sometimes people also call it silicone caulk, is silicone polymer, fillers, catalysts, and additives. It’s a more functionally oriented sealant. Silicone sealant doesn’t offer the same flexibility in appearance as acrylic sealants, and it’s more expensive, but its advantages are significant.
Key Advantages:
- Excellent weather resistance, suitable for outdoor use
- Flexible and resistant to cracking
- Superior waterproof performance
- Durable
What Is Acrylic Sealant
The main components of acrylic sealant are acrylic polymer emulsion, film-forming agents, water, and fillers. This is a cheaper and aesthetically pleasing choice, but its waterproofing, weather resistance, and temperature adaptability are not as strong as those of silicone sealants.
Key Advantages:
- Cheap
- Paintable
- Easy to clean and remove
The Differences between Silicone Sealants and Acrylic Sealants
Cost and Lifespan
In terms of unit price, acrylic sealant undoubtedly has a significant advantage. If you have a limited budget or only need temporary sealing, acrylic sealant would be a good choice. Silicone sealant shines in long-term cost-effectiveness. It is very durable, can last 20 to 25 years, while acrylic sealant only lasts 5 to 8 years under normal use.
Color and Whether It Can Be Painted
Silicone sealant is not paintable. While some measures can force paint to adhere to the surface, the paint coating will quickly crack and peel, making it look even worse than before painting.
Silicone sealant manufacturers offer silicone sealants in many colors, with almond and gray being common. This allows you to match the sealant to your floors and walls without needing to paint it.
Acrylic sealants have excellent compatibility with paints. After full curing, you can apply latex or oil-based paints directly onto the acrylic sealant without the need for a primer, forming a durable paint layer. The paint adheres well to the surface of the acrylic sealant, so you don’t have to worry about it deteriorating quickly.
Read Paint Over Silicone and Other Sealants: What You Need to Know to learn more about painting over sealants.
Adhesion
Silicone sealants are excellent at forming strong bonds with non-porous materials. Non-porous materials are those with a solid surface that doesn’t have small pores that would absorb water, and the most typical example is glass. Silicone sealants can easily adhere to the surfaces of these materials:
- Metals
- Ceramics
- Glass
- Smooth tiles
Acrylic sealants shine in areas where silicone sealants fall short: they can penetrate porous materials and adhere to their surfaces. But acrylic sealants are ineffective on materials with smooth, non-porous surfaces like ceramic tiles. Acrylic sealants perform well when sealing these materials:
- Wood
- Drywall
- Cement
- Stone
Temperature Tolerance Range
Silicone sealants, like most silicone products, have excellent resistance to both high and low temperatures. They can withstand temperatures from -60°C to 200°C and maintain good flexibility even at high temperatures.
Acrylic sealants perform poorly when subjected to extreme temperatures, especially in low-temperature environments, where they lose most of their elasticity. It can only work within a temperature range of -20℃ to 70℃, making it a sealant more suitable for use in normal temperature environments.
Weather Resistance
Silicone sealants can withstand various extreme outdoor environments. They have good resistance to major outdoor threats such as UV radiation and ozone. Once cured, silicone sealants are quite stable due to their unique chemical structure; they do not easily react with or be corroded by external substances. Compared to other sealants, they age and yellow at a much slower rate outdoors.
Acrylic sealants don’t have the same excellent weather resistance as silicone sealants. Although there are acrylic sealants designed for outdoor use, they are still easily damaged by UV radiation and ozone.
Acrylic sealants exposed to outdoor environments for a long time will undergo UV degradation under sunlight. This radiation accelerates the breakdown of their internal structure, causing them to lose flexibility. Visually, acrylic sealants often begin to loosen, crack, and powder after about a year of outdoor use, and may even detach from the joints.
If you need a sealant that can provide continuous and stable sealing for your building or machine in outdoor environments, silicone sealant would be a more suitable choice.
Water Resistance
Water resistance is a major advantage of silicone sealant. It is not afraid of prolonged immersion in water and works well even when used to seal the edges of glass aquariums. Once fully cured, silicone sealant can be used in any wet area. You can find it in hot and humid bathrooms or on window frames frequently exposed to rain.
What’s more, with proper maintenance, mold is difficult to grow on the surface in damp conditions. If applied correctly, the surface of silicone sealant is dense and smooth, preventing the accumulation of dirt, grease, and other chemicals. After cleaning, mold finds it difficult to take hold.
Acrylic sealants are also water-resistant, but they fail more easily when exposed to water for extended periods. If exposed to a consistently damp environment or continuous contact with water, you will observe that it swells due to water absorption. While it may appear to recover after drying, its internal structure has actually changed permanently.
The situation becomes even more serious if it’s used inside a container holding water. Under exposure to water for a long time, it will gradually soften and even partially dissolve. This not only influences the seal but also makes the water unsafe. The softened and damp acrylic sealant is also prone to mold growth.
In dry environments or those with only brief exposure to water, both silicone and acrylic sealants can be used. Once you apply the sealant to areas prone to water accumulation, such as flat roofs or sinks, only silicone sealant is reliable.
Flexibility
After complete curing, silicone sealant is similar to rubber, being soft and elastic. If you stretch it forcefully, it can even be stretched to seven times its original length. This flexibility allows it to move slightly with the objects it connects, and maintain its sealing properties even if the connected structures change.
Silicone sealant can also better withstand thermal expansion and contraction caused by changes in outdoor temperature, and is less likely to crack due to these changes.
Acrylic sealants become harder after curing, making them susceptible to problems caused by movement and frequent temperature changes that alter their shape. In such cases, the seal they form can easily become less effective, and there is even a risk of cracking and complete detachment.
If you are looking for a stable and reliable flexible seal, silicone sealants will perform better.
Difficulty of Cleaning
After long-term use, seals formed by silicone sealant are easier to clean and require less replacement than those made with acrylic sealant.
The surface of cured silicone sealant is very difficult for chemicals to penetrate, so dirt only remains on the surface. What’s more, the surface of silicone sealant is similar to a non-stick pan, which is smooth and non-stick, resistant to water and oil-based chemicals. Cleaning can be easily accomplished with just water and detergent. But please don’t use abrasive cleaning tools such as steel wool, as this will damage the surface of the silicone sealant.
As mentioned earlier, acrylic sealants are quite sensitive to water, so it’s best to wipe away surface dust with a dry cloth. Only consider using water and cleaning agents, which might affect the sealant, when dealing with stubborn stains or mold.
When mold does grow, cleaning is actually quite difficult. The mold and the nutrients that feed it have often penetrated deep into the material, requiring more frequent replacement. This significantly increases long-term maintenance costs and can lead to customer complaints due to cleaning problems.
Therefore, acrylic sealants are more suitable for cleaner areas, as they don’t require frequent cleaning. For areas that get dirty easily, such as some joints in the kitchen, silicone sealants are a better choice.
Are Silicone and Acrylic Sealants Safe? Do They Have Any Odor?
Ordinary Silicone Sealant
The safety of silicone sealants depends on their type. Silicone sealants used in general renovation, machinery, or construction projects release odorous and harmful chemicals during the curing process. These volatile organic compounds (VOCs) typically smell like vinegar or alcohol.
These safety risks can be controlled. During the curing of silicone sealant, open windows and doors for ventilation, and once the odor dissipates, they become safe materials that no longer release VOCs.
Food-grade Silicone Sealant (Food-safe Silicone Sealant)
Among silicone sealants, there is a safer type: food-grade silicone sealant, which can be used for sealing appliances or desks that come into contact with food. While it still releases VOCs during curing, the odor is minimal, and it’s more environmentally friendly.
Its “food-grade” designation primarily means that it doesn’t release harmful chemicals when in contact with food after curing, and it doesn’t contain additives such as BPA and phthalates. These products require strict FDA certification, ensuring their safety.
Acrylic Sealant
Common water-based acrylic sealants release very few VOCs during the curing process and have a milder odor than typical silicone sealants. Relatively speaking, their curing process is safer, but their safety after curing is not guaranteed. Acrylic sealants may contain plasticizers, which remain present after curing and might leach out, posing a health risk.
What’s more, they are not as stable as silicone sealants at high temperatures. For these reasons, acrylic sealants are almost exclusively used in construction and machinery sealing, and not in food and medical manufacturing.
How to Use Silicone Sealant and Acrylic Sealant
The use of these two sealants is similar, and both can be applied to your project or machine using this method:
Step 1:Cleaning
The cleaning steps are very important, especially for silicone sealants, as this directly affects the sealant’s sealing performance and lifespan. Removing old sealant, dust, or other impurities is enough for acrylic sealants. Silicone sealants require further cleaning with acetone or a specialized cleaning agent.
Step 2: Sticking Masking Tape
To achieve better results after construction, apply masking tape to both sides of the gaps where sealant will be used, ensuring they are even. This will result in a neater application of the sealant and allow for easier control of its width.
Step 3:Applying Sealant
Cut the front of the sealant tube at a 45° angle, noting that the size of the cut determines the width of the extruded sealant bead. Then, load the sealant tube into the caulk gun, hold it slightly upright, and move the gun smoothly at 45° to ensure a continuous and even flow of sealant.
Step 4:Trimming
Before the sealant hardens, quickly smooth it with a spatula or a finger covered with a finger cot, ensuring it makes full contact with the material and creates clean, smooth lines.
Step 5:Waiting for Curing
Remove the masking tape and wait for the sealant to fully cure. During this process, ensure the work area is well-ventilated and prevent the sealant from coming into contact with water.
What You Need to Pay Attention to
- Don’t apply at excessively low temperatures, and the suitable temperature range is 10 to 30℃.
- Silicone sealants require a certain level of air humidity for curing, while acrylic sealants shouldn’t be used in excessively humid weather.
- Acrylic sealants shrink after curing and may require a second application.
- For some plastics or other materials that are difficult to adhere to, a primer should be applied before using silicone sealant.
- Some silicone sealants can corrode metal and cement, so please read the instructions carefully.
Applications of Silicone Sealants
Long-term Damp Indoor Environments
For silicone sealants with excellent water resistance, places that are constantly damp, such as sinks, bathrooms, kitchens, and laundry rooms, are undoubtedly where they shine. If you want to further extend their lifespan, you can also purchase kitchen and bathroom mold-resistant sealants that contain mold-resistant ingredients.
Outdoors
The weather resistance of silicone sealants ensures that they last longer in outdoor environments such as roofs, curtain wall joints, and concrete expansion joints, without requiring frequent replacement due to UV exposure, humidity, or temperature changes.
Door and Window Seams
Joints in doors and windows are subject to frequent temperature changes that cause changes in shape, so the sealant used in these areas must have good flexibility. Using silicone sealant here not only prevents cracking but also effectively prevents leaks.
Non-porous Materials
Acrylic sealants are not good at dealing with smooth, non-porous materials such as glass and metal, while silicone sealants are a well-known type of sealant used for glass joints, such as in aquariums. If your project or machinery involves tiles, PVC, or metal, choosing a silicone sealant would be a wiser choice.
Food Packaging, Food Processing and Storage Equipment
For food-related applications where safety is important, cured silicone sealants are necessary. They not only provide a strong seal but also prevent bacterial growth. Most importantly, food-grade silicone sealants don’t release harmful substances even at high temperatures. So silicone sealants, rather than other materials, should be chosen for applications such as water dispensers, commercial kitchen countertops, and food packaging.
Automotive Manufacturing
There are specialized automotive sealants among silicone sealants that are specifically designed for use in automobiles. They can withstand high temperatures, vibrations, and chemicals commonly found in automobiles, thus providing high-quality sealing for housings, sensors, and other components.
Applications of Acrylic Sealants
Interior Windows and Door Frames
If you want to achieve a better visual effect for the edges of interior windows and door frames, paintable acrylic sealant is a good choice. Its surface can be painted to match the color of the walls and floors, making the gaps less noticeable and creating a more harmonious overall look.
Decorative Moldings
You can entrust tasks like ceiling trim, baseboards, and decorative frames to acrylic sealant. As a versatile material that can be used on various wall surfaces, acrylic sealant can be a part of your renovation project. Whether you want to make seams less noticeable or create embossed lines, it can do the job.
Porous Materials
Compared to silicone sealants, acrylic sealants form a stronger bond with porous materials such as plaster and wood. They can be used not only to seal wall or ceiling joints but also to fill gaps in the surface of these materials. After filling the gaps and applying paint, you can achieve a wall that looks like a new one.
FAQ
How Long Does It Take for Silicone and Acrylic Sealants to Cure Fully?
Silicone sealants cure relatively slowly, and complete curing may take more than 3 days. Acrylic sealants solidify on the surface in just 30 minutes and fully cure within 48 hours. If you want to paint over acrylic sealant, you can generally start after about one hour. The curing time may vary depending on the type of product, so please refer to the instructions for details.
How to Remove Old Silicone Sealant?
You can start by using a scraper or utility knife to pry up the bottom of the old silicone sealant, then push to remove as much of the sealant as possible. Next, apply a sealant remover to the remaining residue, wait for a while, and scrape again. Finally, clean off any remaining chemical residue and let it dry before applying the new silicone sealant.
What Is Food-grade and Food-compliant Silicone Sealant?
These are two types of silicone sealants with different safety levels. Food-grade silicone sealant can come into direct contact with food after curing and remain safe, while food-compliant silicone sealant is used for indirect contact with food, such as sealing external gaps in food fermentation tanks.
The simplest way to distinguish between these two types of silicone sealants is to check if they have FDA certification. True food-grade silicone sealants must pass food contact safety certification.
What Is the Difference between One-component and Two-component Silicone Sealants?
Single-component silicone sealants can be used directly and rely on air humidity for curing, while two-component sealants require mixing two materials to cure. Although two-component silicone sealants are more troublesome to use, they offer superior performance and are used in high-end industries such as automotive manufacturing.
Can I Customize Silicone Sealant?
As long as your customized order quantity meets the requirements, some silicone sealant manufacturers fully support customization services. By adjusting fillers and additives, the color, flexibility, adhesion to certain materials, and curing speed of silicone sealants can all be modified.
Final Thoughts
Making the right choice is important, but selecting high-quality sealant products is equally crucial. Legensilico is a Chinese manufacturer specializing in silicone products for over 20 years and supports OEM/ODM. If you would like to learn more about silicone sealants or are looking for a supplier of silicone products that meet FDA, RoHS, and REACH standards, contact us for a free consultation today!
