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SikaBiresin® UR703 UR745

Adjustable elastomeric casting resin for production of flexible molds and parts

SikaBiresin® UR703 UR745 is a 2-component polyurethane elastomeric casting resin for production of flexible molds and parts. The Product features an adjustable mixing ratio that allows selection between two distinct hardness levels, enabling optimal adaptation to specific application requirements.  

  • Two hardness level available A45 to A55
  • Low moisture sensitivity
  • Low shrinkage after hardening
  • Very high elongation at break
  • Good chemical resistance
 
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PRODUCT BENEFITS

  • Two hardness level available A45 to A55
  • Low moisture sensitivity
  • Low shrinkage after hardening
  • Very high elongation at break
  • Good chemical resistance
 

Areas of Application

SikaBiresin® UR703 UR745 is designed for production of flexible molds or parts by hand casting or with 2-component low pressure equipment.
This product is suitable for experienced professional users only. Tests under actual processing conditions and with additional materials such as coatings and release agents must be performed to proof material compatibility.  

Packaging

     

SikaBiresin® UR703 (A)

Canister

9.3 kg

11.4 kg A

SikaBiresin® UR745 (B)

Pail

13.3 kg

8 kg A

A Packaging only for full container loads

 

Product Details

Typical Product Data
Properties

Component A
SikaBiresin® UR703

Component B

SikaBiresin® UR745

Chemical base

Isocyanate

Polyol

Color

 

mixed

Straw yellow

Beige

Beige

Density

 

cured

1.04 kg/l

1.22 kg/l

1.15 kg/l 

Mixing ratio

by weight

by weight

60 : 100

70 : 100 

Viscosity (CQP029-4)

  

mixed

mixed

2400 mPa·s

2000 mPa·s

2300 mPa·s A

2450 mPa·s B

Pot life (CQP021-4)

160 g at 23 °C

35 minutes

Demolding time

18 hours

Curing time

at 23 °C

96 hours

Recommended casting thickness

max. 150 mm

Shore A hardness (CQP023-1 / ISO 868)

A1

A1

45 A, C

55 B, C

Tensile strength (CQP036-6 / ISO 37)

3.5 MPa A, B, C

Tear strength (CQP045-1 / ISO 34)

16 kN/m A, C

18 kN/m B, C

Elongation at break (CQP 036-6 / ISO 37)

1300 % A, C

1100 % B, C

Linear shrinkage (CQP014-5)

1000 x 50 x 10 mm

1 mm/m A, B, C

Glass transition temperature (CQP301-5 / ISO 11357)

0 °C A, B, C

Shelf life

12 months

CQP = Corporate Quality Procedure

A) mixing ratio 60 : 100

B) mixing ratio 70 : 100

C) post curing: 16 hours at 40 °C

Application

Application Information

Surface preparation

The material, processing and mold or master-model temperature shall be between 18 °C – 25 °C.
Make sure the mold or master model is clean, dry, dust and grease free.
If mold or master-model surface is porous, it must be sealed prior applying the release agent.
It is recommended to use wax-based release agents. For further information regarding Sika release agent consult the corresponding Product Data Sheet.

Application

Immediately after mixing pour the Product into the mold starting at the deepest point.
Demolding time may vary depending on casted thickness and room temperature.
To achieve the highest performance, leave the elastomeric mold at a temperature ≥ 23 °C for 5 days before using it.
In case the Product is processed with a 2-component low-pressure equipment, follow the instruction of the equipment supplier.

STORAGE CONDITIONS

Both components must be stored at temperature between 15 °C and 25 °C in original unopened containers.