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Technical Data Sheet

Silwet* 625

Silwet* 625



Silwet 625 spray adjuvant is a proprietary trisiloxane alkoxylate based wetting agent, used as a penetrant for herbicide applications (e.g. glyphosate).


Unlike traditional trisiloxane alkoxylates, which can inhibit uptake of glyphosate into grasses, Silwet 625 spray adjuvant helps overcome this problem, by enhancing performance relative to conventional tallow amine ethoxylate based spray adjuvants.


Although most trisiloxane superspreaders are excellent wetting agents (i.e. Silwet L-77* adjuvant), it has been demonstrated that spreading is not always beneficial to herbicide uptake and performance (Lui, Z.Q.; Zabkiewicz, J.A. 1997. Proc. 50th Plant Protection Conf.: 129-133.). Figure 1 illustrates that superspreading can reduce the concentration of herbicide per unit area. In some cases this is believed to limit herbicide uptake into grasses. Evidence suggests that cuticular penetration of herbicide is favored by organosilicone sprays that do not superspread, thereby giving a higher concentration of herbicide/unit area. Silwet 625 spray adjuvant is designed to provide the penetration properties associated with trisiloxane alkoxylates, but limits the superspreading property to achieve the optimum balance.


Silwet 625 MB indd_Description_image1.JPG


As a result of the unique composition of Silwet 625 spray adjuvant, improved efficacy may be achieved at use levels up to 4 times less than a conventional tallow amine ethoxylate. Figure 2 demonstrates that SIlwet 625 spray adjuvant is an effective adjuvant for glyphosate in controlling barnyardgrass (Echinochloa crus-galli) relative to a trisiloxane alkoxylate superspreader (Silwet L-77 adjuvant), and a tallow amine ethoxylate containing 15 EO units.


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(a) Glyphosate used as the isopropylamine salt at 0.75% in a relative spray volume of 100L/ha. Simulated rainfall was applied at 2 Hours After Treatment (2.5 cm).


Key Features and Benefits

  • Promotes rapid penetration of herbicides into grasses
  • Improves spray coverage
  • Controlled spreading overcomes antagonism associated with TSAs and glyphosate on grasses
  • Reduced use levels relative to tallow amine ethoxylates
  • Low use rates make Silwet 625 spray adjuvant an excellent candidate for “In-can” formulations (25 to 100 g/L formulation)


Typical Physical Properties

Physical Property Result
Appearance at 25°C Clear amber liquid
Surface Tension, mN/m (0.1 wt%) (a) 33
Viscosity (cps) (b) 144
Spread Diameter, mm (0.5 wt%) (c)7
Cloud Point (0.1 wt %), °C >100
Flashpoint, PMCC °C (°F) 82 (180)

(a) Surface Tension by Wilhelmy Plate Method
(B) Brookfield Viscosity: 25°C, Spindle LV-3, 100 rpm
(c) Deionized water, 25°C


Product Usage

In Agrochemical Formulations

Silwet 618 spray adjuvant may be used as a component in agrochemical formulations. Although organosilicone surfactants are subject to hydrolysis under acidic or basic conditions, optimum performance is achieved by buffering the formulation to pH 6.5 -7.5. Additionally, it is recommended that Silwet 618 spray adjuvant be used at a concentration of at least 5%, based on the total formulation.


As A Tank Mix Adjuvant

Silwet 618 spray adjuvant, when used as a tank-side adjuvant may be used to improve spray coverage, improve uptake or to allow for a reduction in spray volume. Silwet 618 spray adjuvant is most effective as a tank-side adjuvant when spray mixtures are 1) within a pH range of 5-8, and 2) used within 24 hours of preparation.


As A Tank Mix Adjuvant
Silwet 625 spray adjuvant, when used as a tank-side adjuvant may improve herbicide performance. Silwet 625 spray adjuvant is most effective as a tank-side adjuvant when spray mixtures are 1) within a pH range of 5-8, and 2) used within 24 hours of preparation.


Typically Silwet 625 spray adjuvant is used at 0.025% to 0.1% in the spray tank.


Patent Status

Nothing contained herein shall be construed to imply the nonexistence of any relevant patents or to constitute a permission, inducement or recommendation to practice any invention covered by any patent, without authority from the owner of the patent.


Product Safety, Handling and Storage

Customers should review the latest Material Safety Data Sheet (MSDS) and label for product safety information, safe handling instructions, personal protective equipment if necessary, and any special storage conditions required for safety.  MSDS are available at or, upon request, from any Momentive Performance Materials (MPM) representative. For product storage and handling procedures to maintain the product quality within our stated specifications, please review Certificates of Analysis, which are available in the Order Center.  Use of other materials in conjunction with MPM products (for example, primers) may require additional precautions. Please review and follow the safety information provided by the manufacturer of such other materials.



Customers must evaluate Momentive Performance Materials products and make their own determination as to fitness of use in their particular applications.

From automotive to healthcare, from electronics to construction, products from Momentive Performance Materials Inc. are practically everywhere you look. We are a global leader in silicones and advanced materials with a 70+ year heritage of innovation and being first to market – with performance applications that improve everyday life. By knowing our customers’ needs and creating custom technology platforms for them, we provide science based solutions to help customers increase performance, solve product development issues and engineer better manufacturing processes.

Contact Information

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Momentive and the Momentive logo are trademarks of Momentive Performance Materials Inc.

*Silwet is a trademark of Momentive Performance Materials Inc.


The information provided herein was believed by Momentive Performance Materials Inc. (collectively with its subsidiaries, “Momentive”) to be accurate at the time of preparation or prepared from sources believed to be reliable, but it is the responsibility of the user to investigate and understand other pertinent sources of information, to comply with all laws and procedures applicable to the safe handling and use of the product, and to determine the suitability of the product for user's intended application or use. All products supplied by Momentive are subject to Momentive’s standard terms and conditions of sale. MOMENTIVE MAKES NO WARRANTY, EXPRESS OR IMPLIED, CONCERNING THE PRODUCT OR THE MERCHANTABILITY OR FITNESS THEREOF FOR ANY PURPOSE OR CONCERNING THE ACCURACY OF ANY INFORMATION PROVIDED BY MOMENTIVE, except that the product shall conform to Momentive’s specifications. Nothing contained herein constitutes an offer for the sale of any products.

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