Two-Component PU (Polyurethane) Sealant for Construction Joint Sealing (Comensflex 8277L)

• Customization: Available
• Bonding Function: Structural Adhesive
• Morphology: Uniform Paste
• Model NO.: Comensflex 8277L
• Material: Polyurethane
• Classification: Room Curing
• Color: Black
• Levelability: Even and Smooth
• Tack-Free Time: ≤12 H
• Complete Dry Time: ≤24 H
• Elastic Recovery Rate: ≥80 %
• Solid Content: ≥99 %
• Hardness(23ºC): 25±5 (Shore a)
• Water Impermeability: 0.4MPa, 2h
• Tensile Strength: ≥2.0 MPa
• Elongation at Break: ≥800 %
• Uses: Construction Expansion Joint
• Transport Package: 22.5kga+4.5kgb Pail
• Specification: ISO9001, ISO14001
• Trademark: Comensflex
• Origin: China
• HS Code: 3506100090
• Production Capacity: 30000tons/Year

Product Description

Description
Comensflex 8277L is a two-component low modulus polyurethane sealant for various joint sealing, which owns the features of high elongation and good elasticity after A and B mixing. It is a high-performance polyurethane material for sealing and waterproofing for construction.
 

Uses

Concrete construction expansion joint, expansion joint of railway, airport runway, and highway/railway bridge.

Characteristics
Easy to apply, high solid content, high elongation, good water resistance, excellent durability and fatigue resistance. Its service life is much longer than asphalt joint sealant. The sealant is of high bonding strength, with no trickling at summer time or hardening and cracking at winter time. It keeps an elastomer permanently, which is effective sealing and waterproofing.

Technical Data

	Items		Unit	Data
1	Levelability			Even and smooth
2	Tack-free time		h	≤12
3	Complete dry time		h	≤24
4	Elastic recovery rate		%	≥80
5	Solid content		%	≥99
6	Hardness (23c)		Shore A	25±5
7	Water impermeability			0.4Mpa, 2h
8	Elasticity modulus	25±2 ºC	Mpa	≤0.3
		-30±2 ºC		≤0.6
9	Tensile strength	Standard condition	Mpa	≥2.0
10	Elongation at break (%)	Standard condition	%	≥800
11	Elasticity at low temperature	Standard condition	-35 ºC	No crack
12	Bonding performance at definite elongation	Heat treatment	60% definite elongation	No breakage
		Alkaline treatment
13	Bonding strength	Dry surface	MPa	≥1.0

Detailed Image



Construction Technology
(1) Preparing Work
Expansion Joint Clearance
The expansion joint should be dry and clean with no sundries such as foam and matchwood, etc. Clear away the quicksand and oil. If necessary, clear away the sundries and quicksand with blower.

Note:
The clearance of the expansion joint is a factor of the good performance of the sealant. The wet or dirty expansion joint will cause bulge or falling down of the sealant. And the oil or dust will impact the bonding effect. Thus, there will be separation between the sealant and the surface under the cold condition. Comens will not shoulder the responsibility if there is quality problem due to the uncleaness of expansion joint.

Pad
According to the need, we usually suggest to use the PE pad under the joint, to avoid stress concentration due to bonding on three sides. The diameter of the round pad should be bigger than the 25% width of the expansion joint to avoid leakage of the sealant.

(2) Comensflex 8277L: Mixing ratio is 5: 1. As the two components are both of non-sagging, put the two components on the tray with the ratio and mix uniformly.

Note:
Comensflex 8277L A/B is of two-component. The mixing ratio must be 5: 1 and assure uniformly mixed as the color appears uniform.

(3) Applying technology
Apply the mixture with spade or spatula into the joints. After working, no water can be put into the sealant within 24 hours.

Note:
(1) The work must be done at appropriate temperature. (Refer to From I).
(2) The consumption is different according to the depth of the expansion joints.
(3) The sealant must be applied in working time, or the work will be affected. (Refer to From I).
(4) The sealant must be conserved for at least 24hs at the humidity less than 80%RH, temperature 5-40.
(5) It does not affect usage if there is slight bubble or bulge after the sealant curing.
(6) The movement capability is 25LM, that is to say the deflection of the expansion joint should be less than 25% of the expansion joint.

Storage and Shelf Life
Store in a cool and dry place. Avoid direct sunlight. If stored at the recommended conditions in original, unopened containers, the shelf life of 8277A is 9months, 8277B is 12months.
Packaging
Comensflex 8277A:22.5kg/pail,
Comensflex 8277B:4.5kg/pail.
1 part Comensflex 8277A match with 1 part Comensflex 8277B

Note
The sealant working time and curing rate are affected by the surrounding conditions. If the temperature is low, the working time and curing time is longer, and the viscosity will be higher; if the temperature is high, the working time and curing time is shorter; if the temperature is too high, there will be bubbles in the sealant. The appropriate temperature is 5-40ºC, humidity is lower than 80%. If the sealant is tacky or soft, it may caused by too high humidity or not enough curing agent.


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