* These values provide general information and are not part of the product specification.
Product description
Aliphatic high-molecular-weight polyester-polyurethane adhesive raw material. Desmomelt® U 320 is a solid raw material for the formulation of non-yellowing, thermally activated adhesives. Desmomelt® U 320 is particularly well suited for applications with low thermal activation temperatures as e.g. in automotive trim, textile, footwear and furniture applications. Desmomelt® U 320 can be used as a hotmelt applied as a filament, foil or powder, as well as a raw material for non-yellowing solvent-based contact and/or heat activated adhesives.
Applications
Desmomelt® U 320 has outstanding bonding properties on most synthetic and natural materials. Desmomelt® U 320 can be blended with other Desmomelt® U grades to adjust properties according to specific needs. The thermal and hydrolysis stability as well as the resistance to plasticizers, grease and oil can be increased by the addition of 1 - 5 % by weight of a polyisocyanate from the Desmodur® range. Attention should be paid to the pot-life of the formulation.
To customize for application-specific and technical properties, dry- or melt formulation may be necessary. Before application, especially by extrusion, the product should be dried at temperatures below 40 °C to avoid any caking of the powder/flakes. For heat activation bonding applications with Desmomelt® U 320, a bond line temperature in the range of > 55 °C is recommended to allow the applied adhesive layer to be fully activated for bonding. Preferably, the bonding process takes place directly after application especially when used with Desmodur® crosslinkers. The actual temperature needed for a specific application will depend on the formulation, time in the press, the pressure applied, and the substrates being bonded.
Desmomelt® U 320 is suitable for solvent-based adhesive formulations. Recommended solvents include acetone, 2-butanone and ethyl acetate, whereby the addition of a protic co-solvent (e.g. 5 %) of ethanol, water (or similar) significantly increases the solubility. As with any product, use of Desmomelt® U 320 in a given application must be tested (including but not limited to field testing) in advance by the user to determine suitability.
Desmomelt® U 320 has excellent adhesive properties on most synthetic and natural materials. Desmomelt® U 320 can be mixed with other Desmomelt® U-types to adapt the properties to specific requirements. Heat resistance, hydrolysis resistance and resistance to plasticizers, greases and oils can be increased by adding 1 - 5 percent by weight of a polyisocyanate from the Desmodur® product range. Attention should be paid to the pot-life of the mixture.
Before application, especially by extrusion, the product should be dried at temperatures below 40 °C.
For heat-activated adhesive applications with Desmomelt® U 320, an adhesive bond-line temperature of > 50 °C is recommended. Preferably, the bonding process takes place immediately after application, especially in the case of mixtures with Desmodur® crosslinkers.The actual temperature required for a particular application depends on the formulation, the time spent in the press, the pressure applied, and the substrates to be bonded. As with any product, the use of Desmomelt® U 320 in a given application must be pre-tested by the user (including but not limited to field trials) to determine suitability.
Form supplied
Powder, sieved over 4 mm.
Particle size distribution may slightly vary without effecting material properties.
Specification
| Property | Test Condition | Value | Unit | Standard |
|---|---|---|---|---|
| Residual moisture | < 0.8 | % | M001 - INTERNAL METHOD | |
| Dynamic viscosity | 23 °C | 50 - 200 | mPa·s | M092 - ISO 2555 |
* viscosity measured by using a solution of 15 wt.% in 2-butanone (MEK) / water (16:1)
Typical Values
| Property | Test Condition | Value | Unit | Standard |
|---|---|---|---|---|
| Density | 20 °C | 1.2 | g/cm³ | EG A3 |
| Minimum activation temperature | 55 - 65 | °C | DIN EN 12961 | |
| Minimum extrusion temperature | 120 | °C | ||
| Recommended processing temperature for extrusion | 200 - 260 | °C | ||
| Hot tack life (depends on application conditions) | 2 - 5 | min | ||
| Heat resistance | 50 | °C |
Storage
- Storage in original sealed Covestro container.
- Recommended storage temperatures: {{storageTemperature}}, temperatures above 30 °C should be avoided.
- Protect from direct sunlight, heat, moisture and foreign material.
General information: Temperatures above 45 °C lead to caking / agglomerat
Storage time
Covestro certifies that the product meets specifications for {{storageTimeWarrantyInMonths}} 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 {{storageTimeWarrantyInMonths}}.
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.
Trial or development Product
This product is provided on a trial basis only. Hazard and performance information may be incomplete and may be updated as additional data becomes available. No assurances are given regarding conformity, processability, or long-term performance. Use of this product is at the sole responsibility and risk of the customer. All warranties, express or implied, are disclaimed. Continued supply is not guaranteed and may be discontinued without notice. Covestro accepts no liability for damages or losses arising from the use of this trial product.
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 .
