SikaBiresin® UR763

Elastomeric casting resin for mold making

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SikaBiresin® UR763 is a 2-component polyurethane elastomeric casting resin for mold making.  

  • Easy sanding after curing
  • Homogeneous material
  • Low moisture sensitivity
  • Chemical resistance to the majority of release agents
  • Casting thickness up to 40 mm
 

Overview

PRODUCT BENEFITS

  • Easy sanding after curing
  • Homogeneous material
  • Low moisture sensitivity
  • Chemical resistance to the majority of release agents
  • Casting thickness up to 40 mm
 

Areas of Application

SikaBiresin® UR763 is designed for production of ceramic case molds by hand casting. 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® UR701 (A)

Canister

5 kg

SikaBiresin® UR763 (B)

Pail

10 kg

 

Product Details

Properties

Component A

SikaBiresin® UR701

Component B

SikaBiresin® UR763

Chemical base

Isocyanate

Polyol

Color

 

mixed

Amber

Pink

Pink

Density

 

cured

1.02 kg/l

1.59 kg/l

1.34 kg/l

Mixing ratio

by weight

by volume

50 : 100

80 : 100

Viscosity (CQP029-4)

 

mixed

800 mPa·s

7000 mPa·s

3000 mPa·s

Pot life (CQP021-4)

150 g at 23 °C

20 minutes

Demolding time

16 hours

Curing time

at 23 °C

6 days

Casting thickness

up to 40 mm

Shore A hardness (CQP023-1 / ISO 868)

63 A

Tensile strength (CQP036-6 / ISO 37)

3.5 MPa A

Tear strength (CQP045-1 / ISO 34)

16 kN/m A

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

800 % A

Linear shrinkage (CQP014-5)

250 x 50 x 3 mm

1 mm/m A

Abrasion resistance (Taber) (ISO 5470)

133 mg/100U A

Glass transition temperature (CQP301-5 / ISO 11357)

-85 °C A

Linear coefficient of thermal expansion (CQP053-1 / ISO 11359)

200 x 10-6 1/K A

Service temperature

-40 – 80 °C

Shelf life

12 months

CQP = Corporate Quality Procedure

A) curing condition: 70 °C for 16 hours

Application

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

Prior to casting the mixing can be left for self-degassing for several minutes. Degassing in a vacuum chamber is not advisable.
Demolding time may vary depending on casted thickness and room temperature. Sanding is possible 4 hours after demolding.
Do not use for production of plaster molds before 2 days after demolding.
In case of ambient temperature above 28 °C it is advised to split the quantity before mixing in 2 smaller volumes in order to get longer working time.

STORAGE CONDITIONS

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