JP-2026514300-A - Polyurethane prepolymer composition

Abstract

This invention provides an NCO-terminated polyurethane prepolymer composition produced by the reaction of methylenediphenyl diisocyanate (MDI) and/or polyphenylene polydimethylene polyisocyanate diisocyanate (pMDI) with a polyol, wherein the amount of residual unreacted diisocyanate monomer is further reduced, as well as a method for producing the polyurethane prepolymer.

Inventors

• ライアン テイラー
• エマニュエル ジュニア ロナルド エム
• リー ウェイ

Assignees

• ユービーイー ウレタンズ ユーエスエー エルエルシー

Dates

Publication Date

20260508

Application Date

20240419

Priority Date

20230421

Claims (11)

1. A polyurethane prepolymer composition manufactured by a method including the following steps: (1) A step of reacting pMDI with a polyol to form a polyurethane prepolymer containing residual monomeric MDI: (2) A step of reducing the amount of residual monomeric MDI in the polyurethane prepolymer.
2. A polyurethane prepolymer composition manufactured by a method including the following steps: (1) A step of reacting monomeric MDI with a polyol to form a polyurethane prepolymer containing residual monomeric MDI: (2) A step of mixing pMDI into the polyurethane prepolymer to form a polyurethane prepolymer mixture containing residual monomeric MDI: (3) A step of reducing the amount of residual monomeric MDI in the polyurethane prepolymer mixture.
3. A polyurethane prepolymer composition according to claim 1 or 2, wherein the amount of residual monomeric MDI relative to the total weight of the prepolymer is 0.4% by weight or less, preferably 0.1% by weight or less.
4. A polyurethane prepolymer composition according to claim 1 or 2, The polyurethane prepolymer composition wherein the polyol is a polyether, preferably PPG, more preferably PPG with a molecular weight of 200 to 10,000 g/mol, and even more preferably 500 to 4,000 g/mol.
5. A polyurethane prepolymer composition according to claim 1 or 2, A polyurethane prepolymer composition wherein the NCO:OH ratio of the polyurethane prepolymer is 1:1 to 10:1, preferably 3:1 to 8:1, more preferably 5:1 to 7:1, and most preferably 7:1.
6. The polyurethane prepolymer composition according to claim 1 or 2, wherein the reduction step is performed by distillation.
7. A method for producing a polyurethane prepolymer, including the following steps: (1) A step of reacting pMDI with a polyol to form a polyurethane prepolymer containing residual monomeric MDI: (2) A step of reducing the amount of residual monomeric MDI in the polyurethane prepolymer.
8. A method for producing a polyurethane prepolymer, including the following steps: (1) A step of reacting monomeric MDI with a polyol to form a polyurethane prepolymer containing residual monomeric MDI: (2) A step of mixing pMDI into the polyurethane prepolymer to form a polyurethane prepolymer mixture containing residual monomeric MDI: (3) A step of reducing the amount of residual monomeric MDI in the polyurethane prepolymer mixture.
9. A method for producing a polyurethane prepolymer according to claim 7 or 8, wherein the NCO:OH ratio of the polyurethane prepolymer is 1:1 to 10:1, preferably 3:1 to 8:1, more preferably 5:1 to 7:1, and most preferably 7:1.
10. The method for producing a polyurethane prepolymer according to claim 7 or 8, wherein the reduction step is performed by distillation.
11. Use of the polyurethane prepolymer composition according to claim 1 or 2 for the manufacture of adhesives and sealants.

Description

Polyurethane prepolymers are widely used in various industries, including coatings, adhesives, sealants, and elastomers. For many adhesive applications, polyurethane prepolymers with low viscosity, high NCO content, and low residual diisocyanate monomer content are preferred. In this specification, such prepolymers containing unreacted diisocyanate monomers are sometimes referred to as "low-free" or "LF" prepolymers. Methylenediphenyl diisocyanate (MDI) is a widely used starting material in the production of polyurethane prepolymers. In this specification, "MDI" refers to isomers of monomeric MDI, namely the 4,4'-, 2,4'-, and 2,2'- isomers of methylenediphenyl diisocyanate. In this specification, polyphenylene polydimethylene polyisocyanate diisocyanate ("pMDI") means a mixture of monomer (bicyclic) MDI and polyaromatic (three-cyclic or more) methylenediphenyl diisocyanate. MDIs with three or more rings are represented by formula I (where n is 1 or greater). (Formula 1) pMDI is commonly used as a binder in the manufacture of rigid foams and in the woodworking industry. Various methods have been investigated to obtain LF MDI-based prepolymers with low viscosity and high NCO content. For example, Reese et al. (EP 1518874) disclose a low-monomer polymethylene polyphenylene polyisocyanate mixture in which a pMDI/MDI mixture is stripped to produce low-monomer pMDI, and then this "low-monomer" pMDI/MDI mixture is mixed with a polyurethane prepolymer in a two-step process to obtain a foam. Therefore, there is a need for further improved compositions and methods for producing LF MDI polyurethane prepolymers having low viscosity, high NCO value, and low MDI monomer content. Surprisingly, it was found that the drawbacks of the conventional technique could be overcome by performing additional distillation in the reaction of pMDI with polyol. As a result, an NCO-terminated prepolymer with increased NCO content and lower viscosity than that obtained by other known methods was obtained. In this specification, unless otherwise stated, all patents, patent applications, patent publications and other publications mentioned and cited herein are deemed to be fully incorporated herein by reference as if they were included in their entirety. To better understand the present invention, as well as its other features and advantages, please refer to the following description. The scope of the present invention is set forth in the attached claims. Detailed description of the invention This invention relates to an NCO-terminated polyurethane prepolymer composition containing pMDI. This prepolymer composition has low viscosity and a high NCO content, and when cured, it can produce a flexible and durable polyurethane adhesive material. The present invention also provides a method for producing such a polyurethane prepolymer by reacting pMDI with a polyol in a specific ratio and under specific reaction conditions, or by reacting MDI with a polyol in a specific ratio and under specific reaction conditions and mixing the result with pMDI. According to at least one preferred embodiment of the present invention, the polyurethane prepolymer composition is broadly envisioned to be produced by a process comprising the following steps: (1) reacting pMDI with a polyol to form a polyurethane prepolymer containing residual monomeric MDI; and (2) reducing the amount of residual monomeric MDI in the polyurethane prepolymer. In another embodiment of the present invention, there is a polyurethane prepolymer composition produced by a process comprising the following steps: (1) reacting monomeric MDI with a polyol to form a polyurethane prepolymer; (2) mixing pMDI with the polyurethane prepolymer to form a polyurethane prepolymer mixture containing residual monomeric MDI; and (3) reducing the amount of residual monomeric MDI in the polyurethane prepolymer mixture. Furthermore, in one embodiment, the polyurethane prepolymer composition has a residual monomeric MDI of 0.4% by weight or less, preferably 0.1% by weight or less, relative to the total weight of the prepolymer. In another embodiment, in the polyurethane prepolymer composition, the polyol is a polyether, preferably polypropylene glycol (PPG), more preferably PPG with a molecular weight of 200 to 10,000 g/mol, more preferably 500 to 4,000 g/mol, and even more preferably 1,500 to 2,500 g/mol. In one embodiment, the polyurethane prepolymer composition is formed by reducing the content of residual monomeric MDI through distillation. In a further embodiment, a method for producing a polyurethane prepolymer composition comprises the following steps: (1) reacting pMDI with a polyol to form a polyurethane prepolymer containing residual monomeric MDI; and (2) reducing the amount of residual monomeric MDI in the polyurethane prepolymer. Similarly, in another embodiment, a method for producing a polyurethane prepolymer composition comprises the following steps: (1) reacting monomeric MDI with a polyol to f