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Two Component Self-leveling PU Construction Joint sealant
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  • Two Component Self-leveling PU Construction Joint sealant
sku: Comensflex 8277L
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Comensflex 8277L Two-Component Polyurethane Sealant for Construction Joint Sealing


This product is a two-component polyurethane sealant for various construction joint sealing and caulking, 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.

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

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.

(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.

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.

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 8277A/B is packed with the ratio of 3: 1. Mix uniformly before applying it. Put the component B into A, then mix with the mixer (around 300rpm, cannot be mixed manually). Mix for at least 3 minutes to assure the materials uniformly mixed. (Note: Scrape the adhering material deposited on the side or bottom of the drum). Put the mixture into a new container according to the consumption, then mix for one more minute.

Comensflex 8277L is of two-component. The mixing ratio must be 3: 1 and assure uniformly mixed.

If there is sediment in component A, it does not affect usage. But component A must be well mixed before mixing with component B.

(3) Applying technology
Put the mixture (A&B) into a suitable container, and affuse into the expansion joint. The level of the affusion should be 2-5mm lower than the joint edge. 30mins after affusion, use a scraper (thinner than the joint) to scrape the surface of the sealant lightly to make the sealant in the joint to form the U section, which meanwhile can eliminate the bubble in the sealant.
After working, no water can be put into the sealant within 24 hours.

(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.


Comensflex 8277L
Item Unit Data
1 Levelability Even and smooth
2 Application time h ≥1
3 Tack free time h ≤12
4 Complete dry time h ≤24
5 Elastic recovery rate % ≥80
6 Solid content % ≥99
7 Hardness(23℃) Shore A 25±5
8 Water impermeability 0.4Mpa, 2h
9 Elasticity modulus 25±2℃ Mpa ≤0.3
-30±2℃ ≤0.6
10 Tensile strength Standard condition Mpa ≥2.0
11 Elongation at break (%) Standard condition % ≥500
12 Elasticity at low temperature Standard condition -35℃ No crack
13 Bonding performance at Heat treatment 60% definite elongation No breakage
14 Bonding strength Dry surface MPa ≥1.0

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