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JP-7856630-B2 - Polyurethane reactive hot melt with long pot life under high heat

JP7856630B2JP 7856630 B2JP7856630 B2JP 7856630B2JP-7856630-B2

Inventors

  • リ、 インジー
  • キン、 シュフイ
  • フランケン、 ウーベ

Assignees

  • ヘンケル・アクチェンゲゼルシャフト・ウント・コムパニー・コマンディットゲゼルシャフト・アウフ・アクチェン

Dates

Publication Date
20260511
Application Date
20210803
Priority Date
20200814

Claims (16)

  1. Polyisocyanates, polyol, MA-SCA acid, Inorganic fillers or one or both of organosilanes, Optionally comprising a thermoplastic polymer and optionally one or more additives, A water-reactive hot-melt adhesive polyurethane composition, which is the product of a mixture substantially free of acids other than the aforementioned MA-SCA acid , The MA-SCA acid is selected from the group consisting of sulfuric acid, phosphonic acid, phosphoric acid, diphosphate, and combinations thereof. A polyurethane reactive hot melt adhesive composition in which the MA-SCA acid is present in an amount of 100 to 800 ppm based on the total weight of the composition .
  2. The polyol is poly(hexanediol adipate), or formula 1: H-[O( CH2 ) m OOC( CH2 ) nCO ] k -O( CH2 ) m -OH; (In the formula, m and n are each even integers, m + n = 8, m and n are independently selected from 2, 4, or 6, k is an integer from 9 to 55, and the polyol of formula 1 has a number-average molecular weight of approximately 2,000 to approximately 11,000.) Alternatively, formula 2: HO-[( CH2 ) 5COO ] p - R1- [OOC( CH2 ) 5 ] q -OH; (In the formula, R1 is an initiator, p is an integer from 0 to 96, q is an integer from 0 to 96, p + q = 16 to 96, and the polyol has a number-average molecular weight of approximately 2,000 to approximately 11,000.) A water-reactive hot-melt adhesive composition according to claim 1, selected from the group consisting of polyester diols having the structure.
  3. The water-reactive hot-melt adhesive composition according to claim 2, comprising both poly(hexanediol adipate) and a polyester diol having the structure of formula 1 or formula 2.
  4. The water-reactive hot-melt adhesive composition according to claim 2, wherein R1 is a glycol initiator residue selected from 1,4'-butanediol, 1,6'-hexanediol, ethylene glycol, and combinations thereof.
  5. The water-reactive hot-melt adhesive composition according to any one of claims 2 to 4, wherein the polyester diol has a number average molecular weight of 2,000 to 10,000 and is present in an amount of 10 to 35% by weight based on the total weight of the adhesive.
  6. The water-reactive hot-melt adhesive composition according to claim 1, wherein the polyol is a polyether polyol having a number-average molecular weight of 1,500 to 6,000, and is present in an amount of 15 to 40% by weight based on the total weight of the adhesive.
  7. The water-reactive hot-melt adhesive composition according to claim 1, wherein the polyol comprises at least one polypropylene glycol.
  8. The water-reactive hot-melt adhesive composition according to any one of claims 1 to 4, 6, and 7, wherein the thermoplastic polymer is an acrylic polymer having a weight-average molecular weight of 30,000 to 80,000, and is present in an amount of 10 to 40% by weight based on the total weight of the adhesive.
  9. The water-reactive hot-melt adhesive composition according to any one of claims 1 to 4, 6, and 7, wherein the thermoplastic polymer is an acrylic polymer having a glass transition temperature of 35 to 85°C and a hydroxyl value of less than 8.
  10. The water-reactive hot-melt adhesive composition according to any one of claims 1 to 4, 6, and 7, wherein the polyisocyanate is present in an amount of 5 to 40% by weight based on the total weight of the adhesive, and/or the polyisocyanate comprises 4,4'-methylenebisphenyl diisocyanate (MDI).
  11. The water-reactive hot-melt adhesive composition according to any one of claims 1 to 4, 6, and 7, wherein the inorganic filler is present in an amount of about 10 to 70% by weight based on the total weight of the adhesive, and/or the inorganic filler is present and calcium carbonate is included.
  12. A water-reactive hot-melt adhesive composition according to any one of claims 1 to 4, 6, and 7, further comprising additives selected from additional fillers, plasticizers, catalysts, colorants, rheology modifiers, flame retardants, UV pigments, nanofibers, defoamers, adhesives, curing catalysts, antioxidants, adhesion promoters, stabilizers, thixotropic agents, and mixtures thereof.
  13. A water-reactive hot-melt adhesive composition according to any one of claims 1 to 4, 6, and 7, further comprising 2,2'-dimorpholinyl diethyl ether (DMDEE).
  14. A product comprising the moisture-reactive hot-melt adhesive composition according to any one of claims 1 to 13.
  15. A method for joining two substrates, comprising applying a hot-melt adhesive according to any one of claims 1 to 4, 6, and 7 in a molten form to a first substrate, then bringing a second substrate into contact with the adhesive on the first substrate, and cooling and curing the adhesive to make it an irreversible solid.
  16. A curing reaction product of a hot melt adhesive composition according to any one of claims 1 to 4, 6, and 7.

Description

This disclosure generally relates to water-reactive polyurethane hot melt adhesives, and more specifically, to water-reactive polyurethane hot melt adhesives that exhibit reduced viscosity increase after aging, improved pot life, and/or improved adhesion to substrates. This section provides background information, not necessarily prior art, regarding the inventive concept related to this disclosure. Hot-melt adhesives are solid at room temperature, but melt into a liquid or fluid state when heated, and are applied to the substrate in this state. The adhesive returns to a solid state when cooled. One type of hot-melt adhesive is thermoplastic hot-melt adhesive. Thermoplastic hot-melt adhesives are generally thermoplastic and can be repeatedly heated to a fluid state and cooled to a solid state. Thermoplastic hot-melt adhesives do not crosslink or harden. The hard phase formed during the cooling of thermoplastic hot-melt adhesives imparts cohesive force, toughness, creep resistance, and heat resistance to the final adhesive. Naturally, the thermoplastic nature limits the upper temperature at which these adhesives can be used. Another type of hot-melt adhesive is the curable or reactive hot-melt adhesive. Reactive hot-melt adhesives start from thermoplastic materials that can be repeatedly heated to a molten state and cooled to a solid state. However, when exposed to suitable conditions, reactive hot-melt adhesives crosslink and harden into an irreversible solid. One type of reactive hot-melt adhesive is polyurethane hot-melt adhesive. Polyurethane hot-melt adhesives contain isocyanate-terminated polyurethane prepolymers that react to extend chains and form new polymers. Polyurethane prepolymers are conventionally obtained by reacting polyols with isocyanates. Polyurethane prepolymers harden when moisture from the atmosphere or on the substrate diffuses into the adhesive and then reacts. The reaction between moisture and residual isocyanate forms carbamic acid. This acid is unstable and decomposes into amines and carbon dioxide. The amines rapidly react with the isocyanate to form urea. The final adhesive product is a crosslinked material polymerized primarily via urea groups and urethane groups. Reactive hot-melt adhesives need to be maintained at their melting temperature during use. However, even when maintained under generally anhydrous conditions, reactive hot-melt adhesives slowly increase in viscosity when kept in a molten state. Ultimately, the equipment needs to be shut down and cleaned to remove the high-viscosity hot-melt adhesive. In highly undesirable cases, reactive hot-melt adhesives may gel or separate phases within the equipment during use. In either situation, shutdown, disassembly, cleaning, and possibly replacement of parts from which the gelled hot-melt adhesive cannot be removed are necessary. Reactive hot-melt adhesives should preferably possess thermal stability, i.e., the ability to resist viscosity changes over time when maintained in a molten state. Naturally, gelation or phase separation of reactive hot-melt adhesives is considered a defect. Typically, reactive hot-melt adhesive formulations contain additives. However, large amounts of fillers and other additives can negatively impact most reactive polyurethane hot-melt adhesives, significantly reducing their thermal stability to undesirable levels. It is desirable to provide reactive polyurethane hot-melt adhesives that maintain thermal stability while incorporating high levels of non-fossil fuel-based, sustainable, and renewable additives. The singular forms "a," "an," and "the" refer to multiple objects unless the context clearly indicates otherwise. As used herein, "approximately" or "about" in relation to numerical values refers to a range of ±10%, preferably ±5%, and more preferably ±1% or less. As used herein, "at least one" means one or more, i.e., 1, 2, 3, 4, 5, 6, 7, 8, 9, or more. Regarding components, it refers to the types of components, not the absolute number of molecules. Therefore, "at least one polymer" means, for example, at least one type of polymer, i.e., one type of polymer or a mixture of several different polymers may be used. As used herein, the terms “comprising,” “comprises,” and “comprised of” are synonymous with “including,” “includes,” “containing,” or “contains,” and are inclusive or unrestricted, and do not exclude any additional unlisted components, elements, or process steps. When quantities, concentrations, dimensions, and other parameters are expressed in the form of ranges, preferred ranges, upper limits, lower limits, or preferred upper and lower limits, it should be understood that any range obtained by combining any upper or preferred value with any lower or preferred value is also specifically disclosed, regardless of whether the resulting range is explicitly mentioned in the context. The terms "preferred" and "preferably" are frequently used herein to refer to embodiments of the disclosure t