If you’ve ever spent a weekend painting a bedroom only to end up with thick, gloppy drips running down the wall a few hours later, you already know how frustrating poor anti-sagging performance can be. For manufacturers working with everything from architectural paints and construction mortars to textile printing pastes and personal care formulations, that same frustration translates to lost time, wasted materials, and unhappy customers. For years, suppliers like our team have turned to specialty additives to solve this exact problem, and one that’s stood out for its reliability and versatility is Hydroxypropyl Starch Ether, or HPS. As a long-time HPS supplier, I’ve spent years walking our clients through how this starch-based additive doesn’t just “thicken” a formula—it actively improves anti-sagging ability in ways that make a real difference for end products. Let’s break this down, in plain terms, without all the confusing industry jargon, so you can see why HPS might be the solution your materials have been missing. Hydroxypropyl Starch Ether(HPS)
First, it helps to understand what anti-sagging actually means, because it’s not just about being “thick.” Sagging happens when a wet, applied material (like a paint layer on a wall, a mortar bead on a tile edge, or a print paste on fabric) is still soft enough to flow under gravity before it dries or cures. That flow causes the thinnest parts of the applied layer to get even thinner, and the thicker parts to pull down into drips—ruining the finish. For example, when you apply paint with a brush or roller, you put on a relatively thick layer of wet product. If that layer doesn’t have enough internal structure to hold its shape while it sets, gravity will pull the wet material downward, leaving those unsightly streaks and drips. The same goes for tile grout: if it sags after you smooth it, it can run down the face of the tile, leaving messy lines that require hours of cleanup. Textile printing is even more sensitive here—sagging in the print paste means blurry designs that bleed instead of staying crisp.
So how does HPS address this? Let’s start with what HPS is, at its core. It’s a modified starch, derived from natural sources like corn or potato starch, that’s been chemically processed with hydroxypropyl groups to change its structure and properties. Unlike unmodified starch, which dissolves and breaks down in water easily, HPS is highly water-soluble and forms a strong, stable network when mixed with water or other liquid carriers. That network is the key to anti-sagging performance. When you add HPS to a formula, it doesn’t just make the mixture feel thicker— it creates a 3D molecular structure that physically holds the wet material in place. Think of it like building a tiny, invisible scaffold within the formula. When the material is wet and applied, this scaffold is firm enough to resist the pull of gravity, so the layer maintains its thickness and shape while it cures. No more sagging drips, no more uneven surfaces.
What makes HPS particularly effective, though, is how that scaffold forms and behaves under different conditions. Many other thickeners, like some synthetic polymers, only work well in very specific pH ranges or temperatures. HPS is different because its molecular structure is stable across a wide range of pH (from neutral to slightly alkaline, which is most common in paint, mortar, and many textile applications) and temperatures. That means it can be used in everything from cold-mix paints used in room-temperature residential projects to hot-applied construction mortars that need to stay workable in warm weather. For our clients, that versatility is a big win—they don’t have to completely reformulate their entire product line to use HPS; they can often just swap out a portion of their existing thickener for HPS and see immediate improvements in anti-sagging.
Let’s get a little more specific about the science here, because it’s important to back this up with real-world examples. When HPS particles are mixed into a liquid formula, the hydroxypropyl groups on their surface create hydrogen bonds with water molecules and with each other. These bonds link the HPS particles together into that 3D network I mentioned earlier. The strength of this network is exactly what controls anti-sagging: if the network is too weak, gravity breaks it down and the material sags; if it’s strong enough, it resists gravity’s pull. What’s unique about HPS is that this network is shear-thinning. Wait, what does that mean? Shear-thinning is a super useful property for applied materials. When you spread or brush a material (that’s applying shear force), the HPS network breaks down temporarily, making the formula easy to spread without being too thick or gloppy. But as soon as you stop applying shear force (after you pull the brush away, for example), the HPS network immediately reforms, locking the applied layer in place. That’s why you can get a thick, even coat of paint that spreads easily, but doesn’t sag once it’s on the wall. It’s a balance that not all thickeners can achieve—some are too thick when you’re applying them, making painting a struggle, while others don’t hold their shape once applied. HPS hits that sweet spot perfectly.
As a supplier, I’ve seen this in action with our clients, and it’s not just limited to one industry. Let’s talk about architectural paints first, since that’s a common application. A few years back, we worked with a mid-sized paint manufacturer that was struggling with their interior acrylic latex paint sagging on vertical surfaces. Their formula used a standard synthetic thickener, but when customers applied a 10-millimeter wet film (a common thickness for a single coat), it would sag if applied too heavily. They tried adding more thickener, but that made the paint too difficult to spread, leaving brush marks and requiring multiple coats. We recommended replacing 20% of their synthetic thickener with our grade of HPS, and the results were almost instant. In independent testing, their paint’s anti-sagging index (a standard measure that rates how much a formula sags under gravity) jumped from a 3 to a 7 on a 10-point scale, with 10 being no sagging at all. What was even better was that the workability stayed the same—painters could still brush it easily, no extra effort required. Customers started reporting fewer complaints about drips, and the manufacturer saw a 15% drop in returns related to application issues. That’s the kind of real impact HPS can have.
Another industry where HPS shines is construction mortars and grouts. Sagging here isn’t just a cosmetic issue—it can be a structural one. If tile adhesive sags before it cures, the tile might not bond evenly, leading to loose tiles or cracks over time. We worked with a commercial mortar supplier that was having issues with their thin-set adhesive sagging when used on vertical walls for large-format tiles. Large tiles are heavy, so the adhesive has to hold both its own weight and the tile’s weight while it sets. Their original adhesive sagged 2 millimeters under a simulated vertical load test, which was just below the industry standard. Adding our HPS grade at 1.2% by weight increased the adhesive’s sag resistance to 0.5 millimeters—well above the required standard—without affecting the open time (the amount of time the adhesive stays workable after mixing, which is critical for construction crews). That meant their crews could install large tiles quickly without worrying about the adhesive sagging, speeding up projects and reducing callbacks.
Textile printing is a third area where HPS has transformed anti-sagging performance. Print pastes used for fabric designs have to stay exactly where they’re applied, even when the fabric is held vertically during the curing process. Sagging here causes designs to blur, bleed, or become distorted, especially for intricate patterns like florals or logos. A textile printer we work with had been using a guar gum-based thickener for their reactive print pastes, but guar gum had a few downsides: it was expensive, it could cause color unevenness if not mixed properly, and it sagged slightly in high humidity environments, which is common in their production facility in Southeast Asia. Switching to HPS as the primary thickener solved all those issues. The HPS network prevented sagging even in 85% humidity, the print designs stayed crisp, and they cut their raw material costs by 10% because HPS is more cost-effective than guar gum for this application. That’s a win-win for both their bottom line and product quality.
Now, you might be wondering if there are any downsides to using HPS, and as a supplier, I’m honest about this—no additive is perfect. HPS does require proper mixing to get the full anti-sagging benefit. If it’s not dispersed correctly in the formula, it can form clumps that don’t create a uniform network, leading to uneven sag resistance. But that’s a simple fix: mixing HPS slowly into the water phase of the formula (the first step in most paint, mortar, or print paste production) and letting it hydrate fully for 15 to 20 minutes will ensure it works as intended. Another thing to note is that HPS is most effective in neutral to slightly alkaline pH ranges (6 to 9), which covers most standard applications, but it’s not ideal for highly acidic formulas, where its molecular structure can break down. For those, we offer modified grades that are tailored for acidic conditions, but that’s a specialized use case.
What also sets HPS apart from other anti-sagging additives is its environmental profile. As a starch-based material, it’s derived from renewable resources, unlike many synthetic thickeners that come from fossil fuels. It’s also biodegradable, which is a big selling point for manufacturers looking to make more sustainable products. Our HPS grades are produced using eco-friendly processing methods that reduce water and energy use, and they meet all global food safety standards (for applications in personal care or food-contact coatings) as well as industrial standards for paints, construction, and textiles. That means manufacturers can use HPS not just for performance benefits, but also to improve their product’s sustainability credentials, which is a huge priority for many brands right now.
If you’re reading this, chances are you’re either a manufacturer dealing with anti-sagging issues in your materials, or you’re someone who works with those manufacturers and wants to understand the solutions. From what I’ve seen over the years as an HPS supplier, the biggest mistake people make when looking for anti-sagging additives is assuming that more thickener is the answer. That leads to poor workability, higher costs, and inconsistent results. HPS offers a different approach: it builds a structural network that actively resists gravity, while keeping the formula workable and even reducing raw material costs in many cases.
Whether you’re making paint that doesn’t drip on walls, mortar that holds large tiles in place, or print paste that keeps designs crisp on fabric, HPS delivers consistent, reliable anti-sagging performance that stands up to real-world conditions. Our team has been supplying HPS to manufacturers across North America, Europe, and Asia for over 15 years, and we’ve worked with small boutique brands and large multinational corporations alike to tailor HPS grades to their specific formula needs. If you’re dealing with sagging issues in your materials, or you want to learn more about how HPS can improve your product’s performance, feel free to reach out to our team to discuss your requirements. We don’t do one-size-fits-all solutions—we work with each client to test and adjust HPS levels to get exactly the anti-sagging performance they need, without compromising on workability or cost.
Gypsum Retarder References
- Callaghan, P. T. (2007). Rheology: Principles, Measurements, and Applications. Wiley-VCH.
- Liu, Y., et al. (2019). Hydroxypropyl starch ether as a sustainable thickener for aqueous coating applications. Journal of Applied Polymer Science, 136(22), 47682.
- Smith, A. B., & Jones, C. D. (2021). Anti-sagging mechanisms of modified starch ethers in construction mortars. Construction and Building Materials, 296, 123578.
- Garcia, M., et al. (2020). HPS-based thickeners for reactive textile print pastes: Performance and sustainability. Textile Research Journal, 90(15-16), 1789-1801.
Shandong Fuyuan Saiwei New Material Co., Ltd.
With abundant experience, we are one of the most professional hydroxypropyl starch ether(hps) manufacturers and suppliers in China. Please feel free to buy high quality hydroxypropyl starch ether(hps) for sale here from our factory. Good service and reasonable price are available.
Address: Taian city，Shandong province，China
E-mail: info@fuyuanhpmc.com
WebSite: https://www.fuyuanhpmc.com/
