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EP-4739744-A1 - WATER-BASED POLYURETHANE ADHESIVE COMPOSITION

EP4739744A1EP 4739744 A1EP4739744 A1EP 4739744A1EP-4739744-A1

Abstract

A water-based polyurethane adhesive composition comprising: (a) a polyurethane polymer comprising a soft segment derived from a polyester polyol and a hard segment derived from a polyisocyanate; wherein the weight ratio between the soft segment and the hard segment is greater than 5.6, and the weight average molecular weight of the polyurethane polymer is no more than 20000 g/mol; (b) water; (c) optionally, a thickening agent, (d) optionally, a defoamer; and (e) optionally, a mattering agent. An activated product obtained from said composition, and an article comprising said activated product or assembled using said composition.

Inventors

  • ZHUANG, Xiaolei
  • KIM, SUNG SOO

Assignees

  • Henkel AG & Co. KGaA

Dates

Publication Date
20260513
Application Date
20230705

Claims (15)

  1. A water-based polyurethane adhesive composition comprising: (a) a polyurethane polymer comprising a soft segment derived from a polyester polyol and a hard segment derived from a polyisocyanate; wherein the weight ratio between the soft segment and the hard segment is greater than 5.6 and the weight average molecular weight of the polyurethane polymer is no more than 20000 g/mol; (b) water; (c) optionally, a thickening agent, (d) optionally, a defoamer; and (e) optionally, a mattering agent.
  2. The composition according to claim 1, wherein the polyester polyol is a polyester diol.
  3. The composition according to claim 2, wherein the polyester diol is selected from poly (ethylene adipate) diol, poly (butylene adipate) diol, poly (neopentylene adipate) diol, poly (hexylene adipate) diol, poly (propylene adipate) diol and combinations thereof.
  4. The composition according to any one of claims 1 to 3, wherein the polyisocyanate is selected from 4, 4’-diphenylmethane diisocyanate (MDI) , isophorone diisocyanate (IPDI) , Toluene diisocyanate (TDI) , Hexamethylene Diisocyanate (HDI) , dicyclohexylmethane-4, 4'-diisocyanate (HMDI) and combinations thereof.
  5. The composition according to any one of claims 1 to 4, wherein the polyurethane polymer (a) is comprised in an amount of 40-55 wt%, preferably 45-50 wt%, based on total weight of the composition.
  6. The composition according to any one of claims 1 to 5, wherein the water (b) is comprised in an amount of 50-60 wt%, preferably 50-55 wt%, based on the total weight of the composition.
  7. The composition according to any one of claims 1 to 6, wherein the thickening agent (c) is comprised in an amount of 0.5-2 wt%, preferably 0.6 to 1.5 wt%, based on the total weight of the composition.
  8. The composition according to any one of claims 1 to 7, wherein the defoamer (d) is comprised in an amount of 0.01-0.2 wt%, preferably 0.05-0.15 wt%, based on the total weight of the composition.
  9. The composition according to any one of claims 1 to 8, wherein the mattering agent (e) is comprised in an amount of 0.01-0.2 wt%, preferably 0.05-0.15 wt%, based on the total weight of the composition.
  10. The composition according to any one of claims 1 to 9, wherein the weight average molecular weight of the polyurethane polymer is greater than 15000g/mol, such as greater than 16000 g/mol, or greater than 18000g/mol, but no more than 20000 g/mol, preferably no more than 19500 g/mol.
  11. The composition according to any one of claims 1 to 10, wherein the weight ratio between the soft segment and the hard segment is greater than 5.65, and preferably less than 10, less than 8.
  12. An activated product obtained from the composition according to any one of claims 1 to 11, wherein the composition is activated at a temperature of no more than 40℃, such as 35℃.
  13. An article comprising the activated product of claim 12 or assembled using the composition according to any one of claims 1 to 11.
  14. The article according to claim 13, wherein the article is selected from shoes, soles, textile products and suitcases.
  15. A method for bonding substrates with the composition according to any of claims 1 to 11, comprising: (i) applying the composition onto one or two substrates, (ii) activating the composition at a temperature of no more than 40℃, such as 35℃, for 3-4 mins (iii) mating and pressing the two substrates together.

Description

Water-based Polyurethane Adhesive Composition Technical field The present invention relates to a water-based polyurethane adhesive composition, to a cured product obtained from said composition, as well as to an article comprising said cured product or assembled using said composition. Background of the invention Nowadays, water-based adhesives are replacing solvent-based adhesives due to environmental protection issues. Water-based polyurethane (PU) adhesives use water as the solvent or dispersant, PU particles are dispersed in the water. Compared with solvent-based PU adhesives, water-based PU adhesives have advantages like no toxicity, nonflammable, low volatiles (VOCs) , low cost and so on. Commercially available water-based PU dispersion (PUD) adhesives usually have an activation temperature of from 50 to 60 ℃, from 80-100 ℃. Such a high activation temperature hinders their use in bonding temperature-sensitive substrates, such as foams, films, synthetic leathers in suitcases, shoes, textile products. There are some water-based PUD adhesives having lower activation temperature, but they cannot achieve both excellent green bond strength and excellent final bond strength. Therefore, there is a need in the art to develop a water-based PU adhesive composition with low activation temperature but can achieve both excellent green bond strength and excellent final bond strength. Summary of the invention After intensive study, the inventors of the present application have found that, by specifically selecting the weight ratio between the soft segment and the hard segment as well as the weight average molecular weight (Mw) of the polyurethane polymer, the water-based polyurethane adhesive composition can be activated at a low temperature and at the same time can achieve both excellent green bond strength and excellent final bond strength. In the first aspect, the present application provides a water-based polyurethane adhesive composition comprising: (a) a polyurethane polymer comprising a soft segment derived from a polyester polyol and a hard segment derived from a polyisocyanate; wherein the weight ratio between  the soft segment and the hard segment is greater than 5.6, and the weight average molecular weight (Mw) of the polyurethane polymer is no more than 20000 g/mol; (b) water; (c) optionally, a thickening agent, (d) optionally, a defoamer; and (e) optionally, a mattering agent. In the second aspect, the present application provides an activated product obtained from the composition of the first aspect. In the third aspect, the present application provides an article comprising the cured product of the second aspect or assembled using the composition of the first aspect. In the fourth aspect, the present application provides a method for bonding substrates with the composition according to the first aspect, comprising: (i) applying the composition onto one or two substrates, (ii) activating the composition at a temperature of no more than 40 ℃, such as 35 ℃, for 3-4 mins, (iii) mating and pressing the two substrates together. The advantages of the present invention include: (1) The composition of the present application can be activated at low temperature, such as lower than 40 ℃, like 35 ℃, 36 ℃, 37 ℃ 38 ℃, 39 ℃, and (2) The activated products of the composition have both excellent green bond strength and excellent final bond strength. Detailed description of the invention It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only and is not intended as limiting the broader aspects of the present invention. Each aspect so described may be combined with any other aspect (s) unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous. Unless specified otherwise, in the context of the present invention, the terms used are to be construed in accordance with the following definitions. Unless specified otherwise, all wt. %or %by weight values quoted herein are percentages by weight. Unless specified otherwise, as used herein, the terms “a” , “an” and “the” include both singular and plural referents. The terms “comprising” and “comprises” as used herein are synonymous with “including” , “includes” or “containing” , “contains” , and are inclusive or open-ended and do not exclude additional, non-recited members, elements or process steps. The term “consisting essentially of” as used herein means that the listed components constitute main body of the composition, for example, at least 90%by weight of the composition. The term “consisting of” as used herein is close-ended and exclude additional, non-recited intentionally added members, elements or process steps. The term “at least one” or “one or more” used herein to define a component refers to the type of the component, and not to the