Mor-Free 421/C-145 December 2009 Page 1 of 4

MOR-FREETM 421/C-145 

Fast Cure Solventless Laminating Adhesive 

Description 

Mor-Free 421/C-145 is a solvent-free, 100% solids, two component polyurethane adhesive system that can

be applied at room temperature. As the reactivity of Mor-Free 421/C-145 is high, the laminates can

generally be further processed in as little as 6 hours. The chemical curing is generally completed within 5 

days at room temperature of 72°F. As always, converters should verify appropriate cure times for their

individual application. 

 

Mor-Free 421/C-145 can be used for laminating all polyolefin films, including LDPE to LDPE, OPP to OPP,

and OPP to LDPE, as well as nylon, aluminum, polyester, and other packaging substrates. The films may

be unprinted or reverse printed with the appropriate laminating grade inks.

Mor-Free 421/C-145 offers rapid bond development to decrease time needed for processing while offering

good metal adhesion. Mor-Free 421/C-145 can be used for a wide range of applications at room 

temperature and below.

Typical Properties*

(Isocyanate) (Polyol)

Mor-Free 421 C-145

Solids 100% 100%

Viscosity 2500-3500 cps 300-400 cps

Weight/Gallon 9.5 lb 8.7 lb

Appearance Clear, Yellow Clear

Mix Ratio 100 pbw 33 pbw

100 pbv 39 pbv

Shelf Life** 360 days 360 days

(unopened containers)

*These items are provided for general information only. They are approximate values and are not

considered part of a product specification.

**Store in tightly closed containers in dry rooms at temperatures of 75°F ± 20°F.

Mor-Free 421/C-145 may react or interact with other components of laminations. Retained volatiles (solvents

or water), slip additives, antiblock agents, and inks are some of the components that may cause property

changes of the laminated structure. If Mor-Free 421/C-145 is used on high slip films (COF < 0.2) or with high

slip LDPE/LDPE laminations, then the user must verify that potential film property changes due to the 

lamination process and materials are acceptable for the end use performance requirements. 

Mor-Free 421 is sensitive to moisture and should be stored under and transferred with dry nitrogen. 

Recommended Coating Weight Range: 0.8 - 1.2 lb/ream

Mor-Free 421/C-145 December 2009 Page 1 of 4

PACKAGING AND

CONVERTING 
This two component solventless adhesive system is virtually independent of the need for moisture for 

curing. 

The original viscosity of the mixture can be reduced by preheating the application rollers to a typical 

temperature of 120° - 140°F (50° - 60°C). Higher temperatures may be required depending on the line 

speed, machine configuration, and choice of substrates. 

A relatively slow initial increase in viscosity is due to the exothermic reaction of the adhesive immediately 

after the mixing process and the mechanical influences in the application system. 

For short trial runs we recommend preparation of no more adhesive than can be used within 

5-10 minutes. A high speed stirrer suitable for a homogeneous mixing should be used. However, the use 

of a meter/mix/dispense device which continuously mixes the adhesive at the chosen ratio, controls the 

feeding of the application unit, and stops production automatically in case of machine failures, is 

indispensable for extended trials and normal production. 

When processing Mor-Free 421/C-145, the safety rules for working with isocyanates must be observed. 

The adhesive contains monomeric MDI. See Material Safety Data Sheet for specific details. 

Cleaning

The application unit should be cleaned before the adhesive becomes insoluble by progressive curing, if 

the machine stops take more than 30 minutes. If the applicable unit and mixing device are combustion 

proof, they may be cleaned with esters or ketones such as ethyl acetate and MEK. 

Several commercially available solvents are safe and effective for flushing and cleaning Mor-Free adhesive

residues from solventless laminators and meter/mix/dispensing equipment that do not have combustion

proof ratings. We recommend contacting either Dynaloy, Inc. (800-669-5709; www.dynaloy.com) or 

Danko Industries (630-882-6070) for cleaning solvent recommendations. Always consult the solvent 

supplier’s MSDS for safety information before use. 

Safety, Handling and Storage 

• Mor-Free 421/C-145 can be stored for 360 days in airtight, closed, original containers in dry rooms at 

temperatures of 70 ± 20°F. Opened containers should be used as quickly as possible. 

• Store in cool, dry, well ventilated area away from heat and ignition sources. Keep container tightly 

closed. 

• Follow good manufacturing and handling practices. 

• Wash thoroughly after handling. Wash contaminated goggles, face shield, and gloves. 

Professionally launder contaminated clothing before re-use. 

• ATTENTION! Container can be hazardous when empty. Follow label warnings even after container 

is empty. Do not reuse empty container without professional cleaning. 

• Refer to Material Safety Data Sheet for more information. 

Mor-Free 421/C-145 December 2009 Page 2 of 4
Pot Life of 100:33 Mor-Free 421/C-145 at 120°F

Mor-Free 421/C-145 December 2009 Page 3 of 4

100

Viscosity, cp

Viscosity (cp)

_______________________________________________________________________ 

Mor-Free is a registered trademark of Rohm and Haas Company.

These suggestions and data are based on information we believe to be reliable. They are offered in good faith, but without guarantee, as

conditions and method of use of our products are beyond our control. We recommend that the prospective user determine the suitability of 

our materials and suggestions before adopting them on a commercial scale. 

Suggestions for uses of our products or the inclusion of descriptive material from patents and the citation of specific patents in this

publication should not be understood as recommending the use of our products in violation of any patent or as permission or license to use 

any patents of the Rohm and Haas Company.

Visit us at http://www.rohmhaas.com/AdhesivesSealants

Rohm and Haas Company, Midwest Technical Center, 2531 Technology Drive, Suite 301, Elgin, IL 60124Phone: 847-649-3800 

Fax: 847-649-3760

14000

12000

00

8000

49°C

6000

4000

2000

0

0:00:00 0:28:48 0:57:36 1:26:24 1:55:12 2:24:00 2:52:48

Time

Viscosity vs. Temperature of Mor-Free 421/C-145

2500

2000

1500

1000

500

0

70 80 90 100 110 120 130

Temperature of Mixture (°F)
Rohm and Haas Food and Drug Opinion 

Name: MOR-FREE 421 

Regulation Complies Opinion 

Date Limitations 

21CFR175.105 Y 09/18/2008

Legend: 

L Yes, this product is cleared with limitations noted

N No, this product is not cleared

Y Yes, this product is cleared.

A Affirmed as compliant based on migration studies.

Regulations: 

21CFR175.105 Adhesives

Disclaimer: 

 This information relates specifically to this product. We believe this information to be accurate and 

reliable as of this date. 

 We recommend that our customers make their own determination on the suitability of this product for 

their particular application.

 We cannot guarantee that the indirect food additives/food-contact status of this product will remain 

unchanged indefinitely; therefore we recommend that you periodically verify its status. 

Name: MOR-FREE COREACTANT C-145 

Regulation Complies Opinion 

Date Limitations 

21CFR175.105 L 02/02/2006 ▪ FOR USE ONLY IN THE PREPARATION OF POLYURETHANE 

RESINS. 

Legend: 

L Yes, this product is cleared with limitations noted

N No, this product is not cleared

Y Yes, this product is cleared.

A Affirmed as compliant based on migration studies.

Regulations: 

21CFR175.105 Adhesives

Disclaimer: 

 This information relates specifically to this product. We believe this information to be accurate 

and reliable as of this date. 

 We recommend that our customers make their own determination on the suitability of this product 

for their particular application. 

 We cannot guarantee that the indirect food additives/food-contact status of this product will 

remain unchanged indefinitely; therefore we recommend that you periodically verify its status. 

Mor-Free 421/C-145 December 2009 Page 4 of 4