Covestro certifies that the product meets specifications for 6 months from the date of shipment, provided it is stored and handled in accordance with the conditions specified in the ‘Storage’ section. After this period, product performance is not assured; Customers are responsible for retesting material before use. Covestro assumes no liability for product performance after 6 months.
Product description
Desmodur® BL 3175A is a blocked aliphatic polyisocyanate based on hexamethylene diisocyanate (HDI) and dissolved in aromatic 100.
Applications
Desmodur® BL 3175A blocked polyisocyanate is used with hydroxyl-functional coreactants in the formulation of light-stable one-component baking systems with relatively low curing temperatures. Coatings based on Desmodur® BL 3175A blocked polyisocyanate are used for the industrial finishing of appliances, coil coating, and can coating, and in the automotive industry for chip-resistant primer-surfacers and topcoats.
The properties of coatings based on Desmodur® BL 3175A blocked polyisocyanate can be influenced, as with two-component polyurethane systems, by the degree of crosslinking and the choice of the polyol. The cure time and temperature required are also dependent upon the choice of coreactant. Combining Desmodur® BL 3175A with hydroxyl-functional polyesters such as Desmophen 670BA gives coatings with high flexibility and hardness. The cure rate can be varied by catalysis without adverse effects on storage. Crosslinking with polyamines or amides may result in limited storage stability.
In coil coating systems, adequate crosslinking may be achieved without catalysis at 465°F peak metal temperature (P.M.T.). With the addition of 1% dibutyl tin dilaurate (DBTDL) based on solid resin, a crosslinking temperature of 435°F P.M.T. is possible. Thermal yellowing may occur at temperatures above 320°F (160°C), depending on the baking time and the polyol used. Testing in Florida indicates that Desmodur® BL 3175A polyisocyanate provides excellent weather stability comparable to Desmodur N 3390A BA/SN polyisocyanate. Desmodur® BL 3175A may also be used as additive to upgrade the flexibility and adhesion of conventional baking systems.
As with any product, use of Desmodur® BL 3175A in a given application must be tested (including but not limited to field testing) in advance by the user to determine suitability.
Specification
| Property | Test Condition | Value | Unit | Standard |
|---|---|---|---|---|
| Turbidity | PQA | ≤ 3 | M082 - ISO 7027 | |
| Non-volatile content | 73.0 - 77.0 | % | M021 - ISO 3251 (modified) | |
| NCO content | ≤ 0.2 | % | M118 - ISO 11909/A | |
| Dynamic viscosity | 25 °C | 2,000 - 4,000 | mPa·s | M014 - ISO 3219/A.3 |
| Color | Hazen | ≤ 60 | M017 - EN 1557 |
Typical Values
| Property | Test Condition | Value | Unit | Standard |
|---|---|---|---|---|
| Flash point | 50.6 | °C | Setaflash (ASTM D-3243, D-3278, D-3828) | |
| Color | yellowish |
Solubility / thinnability
Desmodur® BL 3175A blocked polyisocyanate will yield clear dilutions down to 40% weight solids with ketones, esters, ether esters, and aromatic hydrocarbons. Clear dilutions may be obtained down to 60% weight solids with higher boiling aromatic solvents as aromatic 100 and aromatic 150. Desmodur® BL 3175A is insoluble in aliphatic hydrocarbons.
Compatibility
Desmodur® BL 3175A blocked polyisocyanate exhibits good compatibility with polyols such a Desmophen® 651 MPA, Desmophen 650A 65 PMA, Desmophen 670BA and Desmophen R 221 75. In addition, Desmodur® BL 3175A can be combined with various plasticizers such as phosphoric, sulfonic, adipic, and phthalic esters.
Storage
Desmodur® BL 3175A should be stored in tightly sealed original containers and protected from moisture, heat, and foreign materials. Processability of this product can be adversely affected by contamination. Brief heating to maximum 50ºC has no adverse effect on product properties. Recommended storage temperature is 0º-50ºC. At temperatures above 120°C, Desmodur® BL 3175A begins to decompose.
Storage time
Health and Safety Information
Before working with this product, you must read and become familiar with the available information regarding its risks, proper use, and safe handling. This information is provided in various formats, including the current Safety Data Sheet (SDS) and product label. SDS can be accessed via the following link:
Safety Data Sheets (SDS) for Covestro products | Covestro
For further questions, please use the contact information provided on this technical data sheet.
Disclaimer
Responsibility and Liability
The use of Covestro products, technical assistance, and information (regardless of how provided) is outside Covestro’s control and is solely the responsibility of the customer. The customer must conduct adequate testing to determine the suitability of products for its intended use, including but not limited to technical, health, safety, and environmental aspects. Unless otherwise agreed in writing, all products are sold exclusively under Covestro’s standard conditions of sale, which prevail in case of conflict and are available upon request.
The terms and conditions of sale and delivery are available via the following link:
https://order.covestro.com/covestrostorefront/saleConditions
All information is provided “as is” without warranties, express or implied, including merchantability or fitness for a particular purpose, and is subject to change without notice. To the maximum extent permitted by law, Covestro disclaims, and the customer assumes all liability for losses, damages, or claims arising out of use of Covestro products, technical assistance, or information. Any statement or recommendation not expressly contained in Covestro documentation is unauthorized and shall not bind Covestro. Nothing herein shall be construed as encouraging or recommending the use of any product in conflict with any claim of any patent. No license is implied or in fact granted under the claims of any patent.
Restrictions on Regulated Applications
This product is not intended for use in regulated applications such as agriculture, cosmetics, drinking water contact, food contact, medical products (e.g., medical devices), toys, or similar uses subject to specific regulatory requirements. Prior written approval from Covestro is required before this product may be used in any regulated application. The customer is solely responsible for ensuring compliance with all applicable laws and determining product suitability. Covestro disclaims all liability and warranties for unauthorized regulated uses.
Typical Value
The values provided are typical only and do not represent binding specifications. Unless expressly confirmed in a written contract, these values are not part of the contractual quality agreement and must not be relied upon as a warranty or guarantee of product performance.
Sample
Samples provided by Covestro are intended solely for evaluation and testing purposes by the customer and may not be used in commercial applications, resold, transferred to third parties (except qualified testing service providers acting on behalf of the customer), reverse engineered, modified, or used in any manner not explicitly authorized in writing by Covestro. Samples are provided ‘as-is’ without any warranties, express or implied, including fitness for a particular purpose. Customers are solely responsible for ensuring safe handling, regulatory compliance, and suitability of the material for their intended evaluations. Covestro disclaims all liability for damages or losses arising from the use of samples.
Contact Information
Please use our contact form or contact us directly by sending an e-mail to technical-datasheets@cx.covestro.com .
