Before working with this product, you must read and become familiar with the available information on its risks, proper use, and handling. Information is available in several forms, e.g., in particular in the currently valid safety data sheets and product labels. For further information contact your Covestro representative.
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 |
|---|---|---|---|---|
| Solids | 73 - 77 | % | ||
| Hazen color value | ≤ 60 | |||
| Viscosity | at 25°C | 2,000 - 4,000 | mPa∙s | |
| Free NCO content | ≤ 0,2 | % |
Typical Values
| Property | Test Condition | Value | Unit | Standard |
|---|---|---|---|---|
| Blocked NCO content | 11,1 | % | ||
| Specific gravity | at 25°C | 1,06 | g/cm3 | |
| Appearance | Clear, paleyellow liquid | |||
| Weight per Gallon | at 25°C | 8,83 | lb. | |
| Flash point | (Setaflash) | 51 | °C |
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
Desmodur BL 3175A has a shelf life of six months from date of receipt at customer, provided the material is stored in sealed original containers at the recommended storage temperature.
Health and Safety Information
Disclaimer
General
The manner in which you use our products, technical assistance and information (whether verbal, written or by way of production evaluations), including any suggested formulations and recommendations, are beyond our control. Therefore, it is imperative that you test our products to determine suitability for your processing and intended uses. Your analysis must at least include testing to determine suitability from a technical, health, safety, and environmental and regulatory standpoint. Such testing has not necessarily been done by Covestro, and Covestro has not obtained any approvals or licenses for a particular use or application of the product.
Unless we otherwise agree in writing, all products are sold strictly pursuant to the terms of our standard conditions of sale which are available upon request.
All information and including technical assistance is given without warranty or guarantee and is subject to change without notice. It is expressly understood and agreed by you that you assume and hereby expressly release indemnify us and hold us harmless from all liability, in tort, contract or otherwise, incurred in connection with the use of our products, technical assistance, and information. Any statement or recommendation not contained herein is unauthorized and shall not bind us. Nothing herein shall be construed as a recommendation to use any product in conflict with any claim of any patent relative to any material or its use. No license is implied or in fact granted under the claims of any patent.
Non Medical and non Food Contact
This product is not designated for the manufacture of a medical device or of intermediate products for medical devices (1). This product is also not designated for other specifically regulated applications (e.g. including cosmetics, plant protection, fertilisers, plant strengtheners, food processing, food contact and others). If the intended use of the product is for the manufacture of a medical device or of intermediate products for medical devices or for other specifically regulated applications Covestro must be contacted in advance to provide its agreement to sell such product for such purpose. Nonetheless, any determination as to whether a product is appropriate for use in a medical device or intermediate products for medical devices, for Food Contact products or cosmetic applications must be made solely by the purchaser of the product without relying upon any representations by Covestro.
1) Please see the Guidance on Use of Covestro Products in a Medical Application document.
Sample
Any samples provided by Covestro are for testing purposes only and not for commercial use.
Typical value
These values are typical values only. Unless explicitly agreed in written form, they do not constitute a binding material specification or warranted values
Contact
Please use our contact form or contact us directly by sending an e-mail to technical-datasheets@cx.covestro.com .
