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When selecting between KH-550 and A-1100 for epoxy or fiberglass applications, how do you determine the correct grade and verify supply specifications? Both grades represent gamma-aminopropyltriethoxysilane (CAS 919-30-2) and share identical chemical properties, differing only in manufacturer packaging standards. This article clarifies their technical equivalence, outlines verifiable specification parameters, and details the ordering process for overseas buyers to ensure the product meets your formulation requirements.
Table of Contents
- 1. Chemical Identity and Grade Equivalence
- 2. Hydrolysis Behavior and Aminosilane Stability
- 3. Specification Compliance and Verifiable Parameters
- 4. Application Methods and Dosage Guidelines
- 5. Packaging, Trade Terms, and Ordering
- 6. Further Reading
1. Chemical Identity and Grade Equivalence
KH-550 and A-1100 are commercial designations for the exact same chemical compound: gamma-aminopropyltriethoxysilane. The molecular structure contains a primary amino group and three ethoxy groups. Because they share the identical CAS number (919-30-2) and molecular formula, their fundamental reactivity, density, and boiling points are indistinguishable. The distinction between these grades lies solely in the manufacturing facility, quality control protocols, and packaging formats rather than chemical composition. Formulators can treat them as chemically equivalent when substituting one for the other in standard epoxy or fiberglass sizing recipes, provided the assay purity meets the required threshold.
2. Hydrolysis Behavior and Aminosilane Stability
A critical technical distinction must be made regarding the hydrolysis of aminosilanes. Unlike methacryloxy or glycidoxy silanes, aminosilanes such as KH-550 and A-1100 are inherently basic. Their aqueous solutions are alkaline without the need for external catalysts.
You must not adjust the pH of an aminosilane hydrolysate into an acidic range (e.g., pH 4-5). Acidic conditions are strictly reserved for non-amino silanes like KH-560 or KH-570. For aminosilanes, controlling the stability of the hydrolysate relies on three specific levers:
Restrict the dosage to 0.3%-1% of the filler or resin weight.
Prepare the solution immediately before use and do not store it.
If an acidic environment or extended pot life is strictly required for your process, substitute the aminosilane with the neutral epoxy silane KH-560.
3. Specification Compliance and Verifiable Parameters
Overseas buyers and sourcing engineers require transparent, verifiable data to confirm that the supplied material matches the formulation's technical data sheet. The following table details the standard public constants and specification limits for the aminosilane grades discussed. All parameters are measured under standard laboratory conditions unless otherwise stated.
| Grade | Chemical Name | CAS Number | Functional Group | Density (25°C) | Boiling Point | Recommended Dosage |
|---|---|---|---|---|---|---|
| KH-550 / A-1100 | gamma-aminopropyltriethoxysilane | 919-30-2 | amino (basic) | 0.946 g/cm³ | 217°C | 0.5%-1.5% |
| KH-560 / A-187 | gamma-glycidoxypropyltrimethoxysilane | 2530-83-8 | epoxy (neutral) | 1.070 g/cm³ | 290°C | 0.5%-1.5% |
To verify purity upon receipt, request the factory Certificate of Analysis (COA). The COA will detail the main content, moisture levels, and refractive index. High-performance liquid chromatography (HPLC) can be utilized to verify the main peak purity against the contractual specification sheet. When evaluating the refractive index, ensure the measurement is taken at a controlled temperature of 20°C, as thermal fluctuations can alter the reading. Specific limits for assay, moisture, and refractive index must align strictly with the specifications agreed upon in your purchase contract. Retention samples should be kept for every batch to facilitate future quality comparisons.
4. Application Methods and Dosage Guidelines
The method of incorporation dictates the optimal dosage range and medium. The table below outlines the standard starting parameters for different application methods.
| Grade | Primary Application | Typical Dosage Range | Recommended Medium |
|---|---|---|---|
| KH-550 / A-1100 | Direct addition to resin | 0.5%-1.5% by filler weight | Neat resin or polar solvents |
| KH-550 / A-1100 | Aqueous filler treatment | 0.3%-1.0% by filler weight | Deionized water (prepared immediately) |
| KH-560 / A-187 | Mineral filler treatment | 0.5%-1.5% by filler weight | Water or aliphatic alcohols |
If you are treating mineral fillers via a dry blending process, the silane must be diluted and applied as an atomized spray. Direct pouring of the neat liquid onto the filler often results in localized enrichment and incomplete condensation, leading to sticky, lumpy filler surfaces. Ensure the mixing temperature and duration are sufficient to promote complete condensation on the filler surface.
For pre-hydrolyzed aqueous solutions, always prepare the bath immediately before use. Storing the hydrolysate for extended periods leads to self-condensation. If the solution turns cloudy or forms a white precipitate, the silanol has polymerized into polysiloxane and lost its ability to bond with the filler. Discard the batch and prepare a fresh solution.
5. Packaging, Trade Terms, and Ordering
Understanding the commercial and logistical parameters is essential for integrating silane coupling agents into your international supply chain. We supply KH-550 and A-1100 in standard export packaging specifically designed to prevent moisture ingress and chemical degradation during long-distance transit.
Standard packaging sizes include 25 kg plastic drums, 200 kg steel drums, and 1000 kg IBC tanks. For initial formulation validation, we supply laboratory samples exclusively in 100 g bottles. Please note that 50 g, 500 g, or 1 kg sample sizes are not available for distribution.
Pallet loading quantities are optimized for standard 20-foot and 40-foot shipping containers to maximize freight efficiency. A 20-foot container typically holds 16 to 18 pallets, while a 40-foot container accommodates up to 20 pallets, depending on the drum configuration and total gross weight limits. Drums are securely stretch-wrapped and labeled with batch numbers, net weight, and hazard warnings.
Our standard international trade terms include FOB (Free On Board) and CIF (Cost, Insurance, and Freight). The minimum order quantity is generally based on full drum or full pallet increments. Delivery lead times are subject to confirmation at the time of order, depending on current inventory levels and shipping logistics. Export compliance documents, including REACH registrations or specific destination country chemical declarations, can be provided upon request to ensure smooth customs clearance. All shipments are accompanied by a commercial invoice, packing list, COA, and Material Safety Data Sheet (MSDS). Third-party inspection reports can be arranged and specified in the purchase contract prior to dispatch.
FAQ
What is the minimum order quantity, and can you provide samples and test data?
The minimum order quantity is typically based on full drum increments. Delivery lead times are subject to confirmation at the time of order based on stock and logistics. We can provide 100 g laboratory samples along with a Certificate of Analysis (COA) shipped with the goods. Third-party inspection reports are agreed upon separately.
Can KH-550 and KH-560 be directly interchanged in a PA66 system?
They cannot be directly interchanged. KH-550 is an aminosilane, while KH-560 is an epoxysilane; their functional groups and reaction mechanisms differ. Although the epoxy group in KH-560 can react with the terminal amino groups of PA66, the mechanism and resulting effects are different. You must verify the substitution through small-scale trials.
The pre-hydrolyzed solution turned white and formed a precipitate after two days. Can it still be added to the compound?
No. The white appearance indicates that the silanol has self-condensed into polysiloxane, meaning it has lost the ability to react with the filler. You should discard the batch and prepare a fresh solution. Always prepare hydrolysates immediately before use and do not store them.
We added the silane, but adhesion still fails to meet the standard. Which steps should we troubleshoot?
We recommend troubleshooting three aspects: check if the hydrolysate is clear (for non-amino silanes, verify the pH is between 4 and 5), ensure the dosage is within the reasonable range, and confirm that substrate cleanliness and curing conditions meet the required standards.
During dry blending post-treatment, the filler surface became sticky and formed lumps. What causes this?
This is mostly caused by spraying the neat silane liquid directly onto the filler while the mixing temperature is too low, leading to incomplete condensation or localized enrichment. It is recommended to dilute the silane before atomizing the spray, and to ensure adequate mixing temperature and time.
Further Reading
- KH-550 vs A-1100 vs KBM-903: Aminosilane Cross-Reference
- Silane Coupling Agent: Grade Selection for Fiberglass Matrices
- Silane Coupling Agent: Why glass fibre composites fail
- Silane Coupling Agent: Key Application Scenarios
- Brief: HS Code and Customs Notes for Silane Coupling Agents
- Managing Silane Coupling Agent Cost Volatility: Three Formulation Response Paths
Email us for a quotation together with COA and MSDS.
