Other Features

Paintability—Adhesion of water-borne paints on NTP sealants were measured by 5 X 5 cross-cutting test using 2 mm intervals between cuts (See Fig. 10 and Table 6). The sealant was applied as a sheet ( 3 mm thickness), and after curing for one day at 23 °С, a paint was applied on the sheet and allowed to dry for seven days at 23 °С.

In case of water-borne paints to silicone sealants, cross-cutting tests could not be performed due to paint shedding, since no paint adhesion to the silicone sealant was observed. Meanwhile, the NTP sealant showed good paint adhesion as well as good wetting ability.

FIG. 9—Contact angle after outdoor exposure.

TABLE 5—Water shedding distance after outdoor exposure.

Water shedding distance (mm)

After 1 month

After 2 months

NTP

5

5

SR

40

58

Nonstaining to the Adjacent Area

It is important for construction sealants not to stain the substrate adjacent to the sealing joints. Figure 11 shows silicone and NTP sealants applied on marble and exposed outdoors for four years. No staining was observed with the NTP sealant, while the silicone sealant showed staining.

TABLE 6—Adhesion property of water-borne paints.

NTP

STPE

Paint-A

25/25

25/25

Paint-B

25/25

25/25

Note: Good adhesion: 25/25……………. 0/25: Poor adhesion.

Standardization

As a standard for glass glazing sealant, “AAMA” is well-known, and the NTP holds an official certificate for AAMA802. 3-92, Type 11 (Ductile Back-Bedding Compound).[46]. Furthermore, the durability of the NTP sealant was internally evaluated in accordance with International Standard 1S011600 [7] (Building con­struction – Jointing products – Classification and requirements for sealants), and the NTP sealant has been found to satisfy the requirements of ISO 11600 Class 25HM Type G.

Conclusion

Kaneka has been developing the novel telechelic polyacrylate (NTP) as a new-generation material con­sisting of acrylic polymer as main chain, and their cross-linkable silyl-functionalities at the polymer terminals. NTP sealants have unique features because of their chemical structures, and the new sealants are expected to be used for a wide range of new applications, including SCG.