Hot-melt adhesive composition comprising bio-based polyester polyols

Abstract

The present invention relates to a hot-melt adhesive composition comprising at least one polyester polyol based on Betulin and at least one NCO-terminated compound as well as a method for the production of a laminated article using the inventive hot-melt adhesive composition.

Claims

1. A 1K-polyurethane hot-melt adhesive composition comprising an NCO-terminated compound comprising Betulin units, wherein the NCO-terminated compound comprising Betulin units is the reaction product of: a) at least one polyester polyol that is the reaction product of a reactant mixture comprising Betulin, a dicarboxylic acid, and at least one compound selected from the group consisting of a short-chain polyol, an amine, and a triglyceride; and b) at least one NCO-terminated polyisocyanate compound.

2. The 1K-polyurethane hot-melt adhesive composition according to claim 1 having a softening point of no more than 120 determined according to the method of Ring & Ball.

3. The 1K-polyurethane hot-melt adhesive composition according to claim 1 having a viscosity of 1000 to 100000 mPas, determined at 130? C. according to DIN EN ISO 2555/2000-01 (Brookfield Thermosel, spindle 27, 10 rpm).

4. The 1K-polyurethane hot-melt adhesive composition according to claim 1 wherein the at least one polyester polyol is the reaction product of a reactant mixture comprising Betulin, a dicarboxylic acid, and a short-chain polyol.

5. The 1K-polyurethane hot-melt adhesive composition according to claim 1 wherein the at least one polyester polyol comprises 5 to 80 mol-% of Betulin moieties.

6. The 1K-polyurethane hot-melt adhesive composition according to claim 1 wherein the at least one polyester polyol is the reaction product of a reactant mixture comprising Betulin, a dicarboxylic acid, and a triglyceride.

7. The 1K-polyurethane hot-melt adhesive composition according to claim 1 wherein the dicarboxylic acid is selected from succinic acid, adipic acid, acelaic acid, sebacic acid, lauric acid, myristic acid, furandicarboxylic acid, isophthalic acid, terephthalic acid, orthophthalic acid, dimerized fatty acids and mixtures thereof.

8. The 1K-polyurethane hot-melt adhesive composition according to claim 1 wherein the at least one NCO-terminated polyisocyanate compound is derived from methylenediphenyl diisocyanate (MDI) or its isomers.

9. The 1K-polyurethane hot-melt adhesive composition according to claim 1 wherein the at least one NCO-terminated polyisocyanate compound is in the form of a monomer, an oligomer, a prepolymer or mixtures thereof; wherein the monomer is a polyisocyanate selected from the group consisting of 1,5-naphthylene diisocyanate (NDI), 2,4-diphenylmethylene diisocyanate (MDI), 4,4-diphenylmethylene diisocyanate (MDI), isomers of toluylene diisocyanate (TDI), triphenylmethylene triisocyanate (MTI), hydrated diphenylmethylene triisocyanate (H12MDI), tetramethylenexylylene diisocyanate (TMXDI), isophorone diisocyanate (IPDI), xylylene diisocyanate (XDI), hexane-1,6-diisocyanate (HDI), pentamethylene diisocyanate (PDI), dicyclohexylmethane diisocyanate, and mixtures thereof; and wherein the prepolymer is a reaction product of excess polyisocyanate with an OH-group and/or NH-group carrying compound.

10. The 1K-polyurethane hot-melt adhesive composition according to claim 1 wherein a) and b) are reacted with a ratio of NCO to OH of 5:1 to 1:1.

11. The 1K-polyurethane hot-melt adhesive composition according to claim 1 wherein a) and b) are reacted with a ratio of NCO to OH of 2.5:1 to 1.05:1.

12. The 1K-polyurethane hot-melt adhesive composition according to claim 1 wherein the hot-melt adhesive is moisture curable.

13. The 1K-polyurethane hot-melt adhesive composition according to claim 1 which has a solid content of 100%.

14. The 1K-polyurethane hot-melt adhesive composition according to claim 1 wherein the hot-melt adhesive composition does not contain any water or solvent.

15. The 1K-polyurethane hot-melt adhesive composition according to claim 1 having an application temperature of no more than 170? C.

16. An article comprising the 1K-polyurethane hot-melt adhesive composition according to claim 1.

17. A cured reaction product of the 1K-polyurethane hot-melt adhesive composition according to claim 1.

18. A method for the production of a laminated article comprising: i) providing a first substrate; ii) providing a second substrate; iii) applying the 1K-polyurethane hot-melt adhesive composition according to claim 1 to at least part of at least one of the first or second substrates, and iv) contacting the first and second substrates with the applied adhesive to form a laminated article, wherein the hot-melt adhesive is applied at temperatures of no more than 170? C.

19. The method of claim 18 further comprising exposing the laminated article to moisture to cure the applied adhesive to an irreversible solid form.

Description

EXAMPLES

(1) The following polyester polyols were prepared; the composition being summarized in Table 1.

(2) TABLE-US-00001 TABLE 1 Polyester polyol Composition PES 1 131.63 g Betulin (29.3 mol-%) 25.55 g butane diol (27.9 mol-%) 87.8 g sebacic acid (42.8 mol-%) PES 2 110.65 g Betulin (25 mol-%) 28.51 g butane diol (31.6 mol-%) 63.44 g adipic acid (43.4 mol-%) PES 3 338.55 g Betulin (23.98 mol-%) 87.12 g butane diol (30.31 mol-%) 274.35 g acelaic acid (45.71 mol-%) PES 4 177 g Betulin (46.6 mol-%) 7.73 g butane diol (10 mol-%) 215.27 g dimeric fatty acid (43.4 mol-%) PES 5 177 g Betulin (46.6 mol-%) 7.73 g butane diol (10 mol-%) 215.22 g dimeric fatty acid (43.4 mol-%)

(3) The polyester polyols were found to have the following mechanical properties, summarized in Table 2.

(4) TABLE-US-00002 TABLE 2 viscosity.sup.1) Tg.sup.2) acid OH Mn PES [mPas] [? C.] number.sup.3) number.sup.3) [g/mol].sup.4) polydispersity.sup.5) PES 1 1550 12 2.6 80 1933 2.1 PES 2 7500 29 2.8 59 2207 2.1 PES 3 630 ?15 2.3 73 1725 2.2 PES 4 5500 20 2.9 28 3666 2.3 PES 5 7500 19 1.5 29 4188 2.5 .sup.1)at 130? C. determined with Brookfield Thermosel, spindle 27, 10 rpm .sup.2)glass transition temperature, determined with DSC .sup.3)[mg KOH/g], determined via titration .sup.4)determined with GPC .sup.5)determined with GPC

(5) The obtained polyester polyols were reacted with diphenylmethylene diisocyanate (4,4-MDI) (NCO content 33.6 wt.-%) with a ratio of NCO to OH of 2.2/1.

(6) The obtained adhesive compositions were tested and compared to compositions employing a commonly used polyester polyol based on phthalic acid, commercially available under the trade name Dynacoll? 7130 from Evonik, Germany. The results are summarized in Table 3.

(7) Tensile strength and e-modulus were determined according to EN ISO 527.

(8) TABLE-US-00003 TABLE 3 Example 1 Example 2 Comp.-Ex. 1 Polyester polyol PES 2 PES 3 Dynacoll viscosity (@ 14000 8900 17000 130? C.; [mPas]) setting time [s] 65 40 60 open time [s] 80 60 100 tensile strength 8 12.2 4.1 [MPa] E-modulus [%] 3.6 4.1 44

(9) As can be clearly seen from the provided data, the inventive hot-melt adhesive composition shows advantageous properties that even exceed those of conventionally used petrochemical-based alternatives, in particular with regard to tensile strength and e-modulus.

(10) It was further found that the inventive hot-melt adhesive composition shows a surprisingly high hydrolysis stability. PES 1 and 5 as characterized in Table 1 above were reacted with 4,4-MDI as described above to obtain an inventive hot-melt adhesive composition. The hydrolysis behavior of the obtained inventive hot-melt adhesive compositions was analyzed and compared with a conventional composition employing the polyester polyol sold under the trade name Dynacoll? 7130. After storing the samples for 6 days at 90? C. and 100% relative humidity, the inventive hot-melt adhesive composition did not change in the optical appearance whereas the comparative composition showed clear signs of decomposition. This was confirmed after storage under the same conditions for 21 days where the comparative composition was found to be completely decomposed. In contrast thereto, the inventive hot-melt adhesive compositions maintained their original appearance. The results are briefly summarized in Table 4.

(11) TABLE-US-00004 TABLE 4 Example 3 Example 4 Comp.-Ex. 2 Storage time (PES 1) (PES 5) (Dynacoll?) 6 days solid, slightly brittle, soft, elastic elastic no decomposition decomposition no decomposition 21 days solid, slightly brittle, brittle, elastic no decomposition decomposed no decomposition