Two of the biggest challenges facing the global agricultural market today are increasingly stringent crop protection regulations and the need to feed an ever-growing population. Farmers have the sizable task of continually maximizing their crop yields, which means it is more important than ever to utilize agriculture techniques and products that can be applied as safely, efficiently and optimally as possible.
To this end, farmers have begun to value agricultural adjuvants for their ability to improve the performance of crop protection and crop nutrient products by enhancing the spreading, penetration and rainfastness characteristics of pesticide formulations. Historically, most adjuvant chemistries are derived from petroleum or other chemic al sources, including nonylphenol ethoxylates (NPEs), paraffinic oils, siloxane surfactants and polyglycerolester. With a high manufacturing carbon footprint, the surplus use of these traditional adjuvants in pesticides has the potential to negatively impact the health of humans, animals, fragile biological ecosytems and the environment.
To solve these challenges, pine-based chemistry provider Ingevity developed AltaHance®, a portfolio of sticker adjuvant products made almost exclusively from renewable resources. Compared to the toxic nature of conventional petroleum-derived products, AltaHance increases the effectiveness of agrochemicals while providing higher levels of safety and biodegradability. The unique ability of AltaHance technology to offer tunable rainfastness enables additional spreading and penetration benefits, making it a truly multifunctional adjuvant product line.
The value of a multifunctional, eco-friendly adjuvant technology
Growing awareness among the commercial agricultural community of the value of incorporating natural and renewable ingredients in formulations continues to increase the demand for bio-based adjuvants and foster the development of greener solutions for agricultural applications. A multifunctional technology that offers tunable rainfastness and additional spreading and penetration capabilities, the AltaHance product family is designed for use in crop protection products to enhance the effectiveness of the agrochemical.
AltaHance increases the efficacy of the agrochemical while delivering broad compatibility across various solvents and surfactants, as well as excellent stability over wide temperature ranges and hard water environments. AltaHance products provide the ability to adjust rainfastness at a low dosage rate based on formulation needs, which yields flexibility, easier handling and more robust formulations for agricultural chemical producers. AltaHance can be used as an in-can or tank-mix sticker adjuvant with different active ingredients in various formulation types, including suspension concentrate (SC), emulsifiable concentrate (EC), capsule suspension (CS), solution (SL), suspoemulsion (SE) and more.
Ingevity's AltaHance product offerings are included in Table 1.
Table 1. Basic properties of Ingevity's AltaHance product line
*Viscosity: Brookfield, S21 spindle, 25 ℃, 50rpm; *flash point: close cup; *surface tension: force tensiometer, RT
All three products have relatively low surface tension (similar to methylated soybean oil). Initial spreading tests on tomato and pepper leaves indicated instant wettability and spreading advantages. AltaHance provides additional penetration properties, which improve the uptake of active ingredients through and into plant cuticles. These test results underscore the multifunctional nature of AltaHance and its ability to provide additional accelerated spreading and improved penetration benefits.
Compatibility with various solvents and surfactants
Although AltaHance doesn’t self emulsify, it has impressive compatibility with diverse nonionic surfactants, including ethoxylated distilled tall oil (Ingevity material), sorbitan fatty acid ester ethoxylate, alcohol ethoxylate, nonylphenol ethoxylate and castor oil ethoxylate - which provides flexibility for formulators to select appropriate emulsifiers. AltaHance products have high boiling points and extremely low volatile organic compound content, which ensure product reliability during transportation and user safety. Their sub-zero pour points also make it possible to be used in cold temperatures.
The acid functionality of AltaHance can complex with metal ions, offering excellent performance in hard water. Other challenging conditions, such as cold temperatures (less than 32 ℉), impose performance issues for polyterpene-based sticker adjuvants as sub-ambient environments can escalate the formulation’s viscosity. In contrast, AltaHance products have excellent cold-water emulsification performance and can be used to improve cold-water emulsification for challenging adjuvant products such as polyterpene. Figure 1 shows improved cold-water emulsification when partially replacing polyterpene with AltaHance S.
Figure 1. Emulsification of three sticker/emulsifier blends in 32 ℉ cold water without agitation or inversion. #1: AltaHance S: castor oil ethoxylates (HLB 12.6), 9:1 (wt:wt); #2: Polyterpene: castor oil ethoxylates (HLB 12.6), 9:1 (wt:wt); #3: Polyterpene: AltaHance S: castor oil ethoxylate (HLB 12.6), 6:3:1 (wt:wt:wt)
The unique ability of AltaHance to enable tunable rainfastness
Rainfastness can be customized with the three different AltaHance product offerings: base improvement using AltaHance S; medium improvement with AltaHance 2S; and high improvement with AltaHance 3S. Rainfastness evaluation is based on the American Society of Testing and Materials (ASTM) method STP1579 with minor modifications.
Shown in Figure 2, AltaHance provides a significant improvement in rainfastness for glyphosate SL as a tank-mix adjuvant at a 5% dosage level. Without the sticker, glyphosate SL suffered low rainfastness (1.5% retention). With the addition of AltaHance, the retention increased to 11.3%, 19.7% and 46.0% for AltaHance S, AltaHance 2S and AltaHance 3S, respectively.
Figure 2. Rainfastness of AltaHance with glyphosate SL as a tank-mix adjuvant.
Figure 3 demonstrates AltaHance 3S used as an in-can adjuvant (1-10% of the total formulation) for a commercial mancozeb SC formulation. After long-term storage tests (54 ℃ for two weeks and freeze-thaw), the formulations containing AltaHance 3S had minimal particle-size growth and the suspensibility remained unchanged. However, the compatibility of AltaHance for use as an in-can adjuvant must be evaluated on a case-by-case basis.
Figure 3. Rainfastness of AltaHance with mancozeb SC as an in-can adjuvant. AltaHance 3S: castor oil ethoxylates, 9:1 (wt:wt).
Table 2 shows AltaHance applied in different formulation types with various active ingredients. Rainfastness improved at a minimum 4% adjuvant dosage in every formulation type with all active ingredients studied. In some cases, tremendous rainfastness improvement was achieved at a 1% dosage rate, as seen in Figure 3. Specifically, AltaHance increased rainfastness by 30-60% in the SC formulation at a 4% dosage rate. This range contained all three AltaHance products with AltaHance S providing base rainfastness improvement (roughly 30%), AltaHance 2S providing slightly more (roughly 45%), and AltaHance 3S (roughly 60%) being the most efficient sticker and providing the highest retention.
Table 2. AltaHance in various formulation types with different active ingredients as a tank-mix or in-can sticker adjuvant.
Leaching can occur when too much pesticide is applied on the crop surface or is carried off the application site into water. AltaHance prevents runoff and leaching by adsorbing into the surface and protecting the pesticide from rainfall. Figure 4 below shows the addition of AltaHance as a tank-mix adjuvant into the diluted pendimethalin EC formulation resulted in more active ingredients residing in the top soil, and overall less leaching out from the soil column.
Figure 4. Anti-leaching properties of AltaHance for pendimethalin EC in packed sandy soil.
Achieve the highest crop yield with Ingevity's sustainable adjuvant technology
As farmers work to continually maximize crop yields to feed the world’s growing population, they look for innovative ways to incorporate renewable products into their pesticide formulations without sacrificing performance characteristics. The incorporation of Ingevity's AltaHance sticker adjuvant portfolio of products into existing crop protection formulations and processes not only provides comparable performance to traditional petroleum-based adjuvant chemistries, but also provides additional benefits, like tunable rainfastness, accelerated spreading, increased penetration, and high performance under challenging conditions. This multifunctional product family is positively impacting the global agricultural market by improving pesticide performance without threatening the environment.
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This article was initially published in AgroPages '2020 Formulation & Adjuvant Technology' magazine. Download it to read more articles.