Polyurethane adhesive

Abstract

The polyurethane adhesive may include an isocyanate prepolymer and a polyol component. The isocyanate prepolymer is the reaction product of 35% to 95% by weight of a polyisocyanate and 65% to 5% by weight of a non-dimer acid-based polyester polyol. The non-dimer acid-based polyester polyol may include the reaction product of a primary polyol having a hydroxyl functionality of at least 3 and a weight average molecular weight of 800 g / mol or less, a C4 to C20 non-dimer acid dicarboxylic acid, and a C10 to C20 aliphatic monocarboxylic acid. The polyol component includes 20% to 80% by weight of a hydrophobic polyol, 3% to 15% by weight of a phosphoric acid-modified polyol, and 10% to 30% by weight of a vegetable oil polyurethane polyol.

Description

[Technical Field]

[0001] Embodiments of the present disclosure are directed to adhesives, particularly polyurethane adhesives. [Background technology]

[0002] As the adoption of electric vehicles (EVs) continues worldwide, the economical production of battery packs has made significant progress in recent years. Due to their low cost, low volatility, high body strength, and toughness, polyurethane adhesives have emerged as a popular solution for battery pack assembly, where battery cells are bonded together using polyurethane adhesives. Bonding substrates for battery pack assembly primarily include aluminum alloys (Al alloys), polyethylene terephthalate (PET) films, and polycarbonate films, among other materials. Al alloy-to-Al alloy surface bonding is often the most challenging aspect of battery pack assembly. Specifically, achieving effective bonding between Al alloys is difficult due to their high surface energy and the absence of organic chemical groups on the Al alloy surface.

[0003] On the other hand, moisture resistance of polyurethane components (including polyol and isocyanate portions) is another important industrial need. This is because both polyol and isocyanate portions readily absorb moisture. For the isocyanate portion, absorbed moisture causes a decrease in the isocyanate (NCO) content and the formation of a solid skin that begins on the surface of the component. As a result, the decrease in NCO content can lead to inaccurate feed ratios between reactive groups, and the thick skin can clog storage tanks and / or distribution tunnels, causing product defects and production interruptions, respectively. For the polyol portion, absorbed moisture can cause air bubbles to form in the adhesive after mixing and / or dispensing. Therefore, the higher the moisture resistance of the adhesive, the better.

[0004] To provide moisture resistance, PU adhesives typically incorporate hydrophobic compounds such as vegetable oils, OH-terminated polyalkenes, dimeric acid-based polyesters, and large amounts of hydrophobic plasticizers. However, these compounds are expensive, increase production cycle times (due to their low reactivity), and often reduce the bonding strength of Al alloy-Al alloy interfaces. Therefore, new technologies are needed to solve industrial challenges and enable advanced adhesive products for batteries, especially those for EV applications. Summary of the Invention

[0005] The present disclosure provides polyurethane adhesives that contain both an isocyanate prepolymer and a polyol component, which are low cost yet still provide high reactivity for effective bonding of Al alloy-Al alloy interfaces. Thus, such polyurethane adhesives provided herein can be beneficial because they help solve industrial problems and enable advanced adhesive products for batteries, particularly batteries for EV applications.

[0006] The present disclosure provides a polyurethane adhesive comprising an isocyanate prepolymer and a polyol component, wherein the isocyanate prepolymer is the reaction product of 35 weight percent (wt%) to 95 wt% of a polyisocyanate and 65 wt% to 5 wt% of a non-dimer acid-based polyester polyol, the wt% being based on the total weight of the isocyanate prepolymer, and the wt% of the polyisocyanate and the non-dimer acid-based polyester polyol do not exceed 100 wt% in total. For various embodiments, the non-dimer acid-based polyester polyol comprises the reaction product of a primary polyol having a hydroxyl functionality of at least 3 and a weight average molecular weight of 800 g / mol or less, a C4-C20 non-dimer acid dicarboxylic acid, and a C10-C20 aliphatic monocarboxylic acid, wherein the aliphatic monocarboxylic acid and the primary polyol have a molar ratio of greater than 0.9:1 to 6.5:1 (monocarboxylic acid:polyol), and the aliphatic monocarboxylic acid is present in the isocyanate prepolymer in an amount of greater than 7.2 wt% to 55 wt%, based on the total weight of the isocyanate prepolymer. The polyol component comprises 20 wt% to 80 wt% hydrophobic polyol, 3 wt% to 15 wt% phosphoric acid-modified polyol, and 10 wt% to 30 wt% vegetable oil polyurethane polyol, where the weight percentages are based on the total weight of the polyol component, and the weight percentages of the hydrophobic polyol, phosphoric acid-modified polyol, and vegetable oil polyurethane polyol do not total more than 100 wt%. DETAILED DESCRIPTION OF THE INVENTION

[0007] The present disclosure provides polyurethane adhesives that contain both an isocyanate prepolymer and a polyol component, which are low cost yet still provide high reactivity for effective bonding of Al alloy-Al alloy interfaces. Thus, such polyurethane adhesives provided herein can be beneficial because they help solve industrial problems and enable advanced adhesive products for batteries, particularly batteries for EV applications.

[0008] Numerical ranges disclosed herein are inclusive of all values, including the lower and upper values, and ranges that include explicit values ​​(e.g., a range of 1, or 2, or 3-5, or 6, or 7) also include any subranges between any two explicit values ​​(e.g., the range 1-7 above includes subranges such as 1-2, 2-6, 5-7, 3-7, 5-6, etc.).

[0009] An isocyanate containing more than one, or at least two, isocyanate groups is a “polyisocyanate.” The isocyanate may be aromatic or aliphatic.

[0010] For various embodiments, the present disclosure provides polyurethane adhesives that are the reaction product of an isocyanate prepolymer and a polyol component. As provided herein, the isocyanate prepolymer is the reaction product of a polyisocyanate and a non-dimer acid-based polyester polyol, as discussed herein. The polyol component includes a hydrophobic polyol, a phosphoric acid-modified polyol, and a vegetable oil polyurethane polyol, as discussed herein. The polyol component may optionally include a polyether polyol. Each of the various components is discussed below.

[0011] Polyol component For various embodiments, the polyol component comprises 20 weight percent (wt%) to 80 wt% of a hydrophobic polyol, 3 wt% to 15 wt% of a phosphoric acid-modified polyol, and 10 wt% to 30 wt% of a vegetable oil polyurethane polyol, where the wt% are based on the total weight of the polyol component, and the wt% of the hydrophobic polyol, phosphoric acid-modified polyol, and vegetable oil polyurethane polyol do not exceed 100 wt%. Preferably, the polyol component comprises 24 wt% to 40 wt% of a hydrophobic polyol, 6 wt% to 11 wt% of a phosphoric acid-modified polyol, and 11 wt% to 20 wt% of a vegetable oil polyurethane polyol, where the wt% are based on the total weight of the polyol component, and the wt% of the hydrophobic polyol, phosphoric acid-modified polyol, and vegetable oil polyurethane polyol do not exceed 100 wt%. Most preferably, the polyol component comprises 25 wt% to 30 wt% hydrophobic polyol, 7 wt% to 9 wt% phosphoric acid-modified polyol, and 11 wt% to 15 wt% vegetable oil polyurethane polyol, the weight percentages being based on the total weight of the polyol component, and the weight percentages of the hydrophobic polyol, phosphoric acid-modified polyol, and vegetable oil polyurethane polyol not exceeding 100 wt% in total.

[0012] Hydrophobic Polyol The hydrophobic polyol for the polyol component refers to a hydrophobic polyol having at least two hydroxyl groups. In one embodiment, the hydrophobic polyol is castor oil or a derivative thereof. The polyol component comprises 20 wt% to 80 wt%, preferably 22 wt% to 60 wt%, more preferably 24 wt% to 40 wt%, and even more preferably 25 wt% to 30 wt% of the hydrophobic polyol, preferably castor oil, based on the total weight of the polyol component.

[0013] Phosphate-modified polyol The phosphoric acid-modified polyol for the polyol component is preferably a phosphoric acid-modified polyol, more preferably a phosphate ester polyol. The phosphate ester polyol can be made from trifunctional propylene glycol, polyphosphoric acid, and polyisocyanate. Examples of commercially available trifunctional propylene glycols include products sold under the trade names VORANOL™ CP-450, VORANOL™ CP-260, VORANOL™ CP-755, and VORANOL™ CP-1055, each available from The Dow Chemical Company. In some embodiments, the phosphate ester polyol has a phosphoric acid content of less than 4 wt.% based on the weight of the phosphate ester polyol, or a phosphoric acid content of 0 wt.% to 3 wt.% based on the weight of the phosphate ester polyol, or a phosphoric acid content of 1.5 wt.% to 2.5 wt.% based on the weight of the phosphate ester polyol. In some embodiments, the phosphate ester polyol has a viscosity of less than 40,000 cps at 25°C, or less than 30,000 cps at 25°C, as measured by the method of ASTM D2196. In some embodiments, the phosphate ester polyol has a hydroxyl equivalent weight of less than 330 g / mol. In some embodiments, the phosphate ester polyol has from 0% to 100% by weight, based on the weight of the phosphate ester polyol, of a trifunctional polyether polyol having an equivalent weight of less than 2,000 g / mol. The polyol component comprises from 3% to 15% by weight, preferably from 4% to 13% by weight, more preferably from 5% to 12% by weight, even more preferably from 6% to 11% by weight, and most preferably from 7% to 9% by weight, of a phosphoric acid-modified polyol, preferably a phosphate ester polyol, based on the total weight of the polyol component.

[0014] Vegetable Oil Polyurethane Polyol The vegetable oil polyurethane polyol for the polyol component is a reaction product of a reaction mixture of a vegetable oil containing a hydrophobic polyol having at least two hydroxyl groups, a polyisocyanate, and a polyol. The polyisocyanate can be chemically bonded to the polyol to form a prepolymer. Non-limiting examples of suitable polyisocyanates include aromatic isocyanates, aliphatic isocyanates, carbodiimide-modified polyisocyanates, and combinations thereof.

[0015] "Aromatic polyisocyanate" refers to a polyisocyanate containing one or more aromatic rings. Non-limiting examples of suitable aromatic polyisocyanates include isomers of methylene diphenyl dipolyisocyanate (MDI), such as 4,4-MDI, 2,4-MDI, and 2,2'-MDI, or modified MDI, such as carbodiimide-modified MDI or allophanate-modified MDI, isomers of toluene-dipolyisocyanate (TDI), such as 2,4-TDI and 2,6-TDI, isomers of naphthalene-dipolyisocyanate (NDI), such as 1,5-NDI, and combinations thereof.

[0016] An "aliphatic polyisocyanate" is a polyisocyanate in which the isocyanate moiety (-NCO) is not directly linked to an aromatic ring. Non-limiting examples of suitable aliphatic polyisocyanates include isomers of hexamethylene dipolyisocyanate (HDI), isophorone dipolyisocyanate (IPDI), xylene dipolyisocyanate (XDI), methylenebiscyclohexylisocyanate (hydrogenated MDI) (HMDI) and other cycloaliphatic isocyanates such as cyclohexane diisocyanate, and combinations thereof.

[0017] In one embodiment, the polyisocyanate is selected from mono-polyisocyanates, di-polyisocyanates, tri-polyisocyanates, and combinations thereof. In a further embodiment, the polyisocyanate is a di-polyisocyanate. In one embodiment, the polyisocyanate is a multifunctional polyisocyanate having at least two isocyanate groups or at least three isocyanate groups. In one embodiment, the polyisocyanate is selected from MDI, TDI, HDI, and combinations thereof. In a further embodiment, the polyisocyanate is MDI. Examples of commercially available polyisocyanates suitable for use in accordance with the present disclosure include products sold under the trade names ISONATE™ OP 50, ISONATE™ 125M, and ISONATE™ M143 Modified MDI, each available from The Dow Chemical Company.

[0018] The polyol for preparing the vegetable oil polyurethane polyol may be a polyester polyol, a polyether polyol, or a combination thereof, and is preferably a polyether polyol. "Polyether polyol" is a compound that is both a polyether and a polyol. Non-limiting examples of suitable polyether polyols include polyaddition products of ethylene oxide, propylene oxide, tetrahydrofuran, butylene oxide, and their co-addition products and graft products, polyether polyols obtained by condensation of polyhydric alcohols, or mixtures thereof, and combinations thereof.

[0019] Non-limiting examples of suitable polyether polyols include polypropylene glycol (PPG), polyethylene glycol (PEG), polybutylene glycol, polytetramethylene ether glycol (PTMEG), and combinations thereof. In one embodiment, the polyether polyol is polypropylene glycol (PPG). Non-limiting examples of suitable polypropylene glycols include products sold under the trade name VORANOL™ P-400, available from The Dow Chemical Company.

[0020] Non-limiting examples of suitable polyether polyols include VORANOL™ 1010 L (PPG) and VORANOL™ CP450 (glycerin propoxylated polyether triol), each available from The Dow Chemical Company.

[0021] In one embodiment, the polyether polyol has a Mw of 50 g / mol, or 100 g / mol, or 400 g / mol, or 450 g / mol to 1,000 g / mol, or 1,500 g / mol, or 2,000 g / mol, or 4,000 g / mol, or 5,000 g / mol. In one embodiment, the polyether polyol has a hydroxyl number of 30 mg KOH / g, or 50 mg KOH / g, or 75 mg KOH / g, or 100 mg KOH / g to 115 mg KOH / g, or 125 mg KOH / g, or 150 mg KOH / g, or 200 mg KOH / g, or 300 mg KOH / g, or 350 mg KOH / g, or 400 mg KOH / g, or 450 mg KOH / g, or 500 mg KOH / g. In one embodiment, the polyether polyol has one or both of the following characteristics: (i) a Mw of 50 g / mol to 5,000 g / mol, or 100 g / mol to 2,000 g / mol, or 400 g / mol to 1,500 g / mol, or 400 g / mol to 1,000 g / mol, and / or (ii) a hydroxyl number of 30 mg KOH / g to 500 mg KOH / g, or 100 mg KOH / g to 400 mg KOH / g, or 100 mg KOH / g to 150 mg KOH / g, or 350 mg KOH / g to 400 mg KOH / g.

[0022] In some embodiments, the vegetable oil containing a hydrophobic polyol having at least two hydroxyl groups can be castor oil or a derivative thereof.

[0023] Vegetable oil polyurethane polyols can be formed from the reaction product of a vegetable oil containing a hydrophobic polyol having at least two hydroxyl groups, a polyisocyanate, and polypropylene glycol. A suitable reaction involves mixing 8% to 26% by weight of a polyisocyanate, 40% to 50% by weight of a vegetable oil containing a hydrophobic polyol having at least two hydroxyl groups, and 40% to 50% by weight of polypropylene glycol under an inert atmosphere (e.g., nitrogen) at a temperature of 40°C to 100°C for 1 to 5 hours (wherein the total weight of the polyisocyanate, the vegetable oil containing a hydrophobic polyol having at least two hydroxyl groups, and the polypropylene glycol does not exceed 100% by weight).

[0024] The polyol component comprises 10% to 30% by weight, preferably 11% to 25% by weight, more preferably 11% to 20% by weight, and most preferably 11% to 15% by weight of vegetable oil polyurethane polyol, based on the total weight of the polyol component.

[0025] Polyether polyol The polyol component may further comprise a polyether polyol. Non-limiting examples of suitable polyether polyols include polyaddition products of ethylene oxide, propylene oxide, tetrahydrofuran, butylene oxide, and their co-addition and graft products; polyether polyols obtained by condensation of polyhydric alcohols; or mixtures thereof, and combinations thereof. Non-limiting examples of suitable polyether polyols include polypropylene glycol (PPG), polyethylene glycol (PEG), polybutylene glycol, polytetramethylene ether glycol (PTMEG), and combinations thereof. In one embodiment, the polyether polyol is polypropylene glycol (PPG). Non-limiting examples of suitable polyether polyols include VORANOL™ 1010 L (PPG) and VORANOL™ CP450 (glycerin propoxylated polyether triol), each available from The Dow Chemical Company.

[0026] In one embodiment, the polyether polyol has a Mw of 50 g / mol, or 100 g / mol, or 400 g / mol, or 450 g / mol to 1,000 g / mol, or 1,500 g / mol, or 2,000 g / mol, or 4,000 g / mol, or 5,000 g / mol. In one embodiment, the polyether polyol has a hydroxyl number of 30 mg KOH / g, or 50 mg KOH / g, or 75 mg KOH / g, or 100 mg KOH / g to 115 mg KOH / g, or 125 mg KOH / g, or 150 mg KOH / g, or 200 mg KOH / g, or 300 mg KOH / g, or 350 mg KOH / g, or 400 mg KOH / g, or 450 mg KOH / g, or 500 mg KOH / g. In one embodiment, the polyether polyol has one or both of the following characteristics: (i) a Mw of 50 g / mol to 5,000 g / mol, or 100 g / mol to 2,000 g / mol, or 400 g / mol to 1,500 g / mol, or 400 g / mol to 1,000 g / mol, and / or (ii) a hydroxyl number of 30 mg KOH / g to 500 mg KOH / g, or 100 mg KOH / g to 400 mg KOH / g, or 100 mg KOH / g to 150 mg KOH / g, or 350 mg KOH / g to 400 mg KOH / g.

[0027] The polyol component contains 5% by weight to 20% by weight, preferably 7% by weight to 18% by weight, more preferably 9% by weight to 15% by weight, and even more preferably 10% by weight to 14% by weight of polyether polyol, based on the total weight of the polyol component.

[0028] Chain extender The polyol component may optionally include a chain extender. Non-limiting examples of suitable chain extenders include glycerin, trimethylolpropane, diethylene glycol, propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol (1,4-BDO), and combinations thereof, preferably 1,4-BDO. The polyol component includes 1 to 20% by weight, preferably 2 to 15% by weight, more preferably 4 to 10% by weight, and even more preferably 2 to 6% by weight of the chain extender, preferably 1,4-BDO, based on the total weight of the polyol component.

[0029] The polyol component may optionally include moisture scavengers, catalysts, flame retardants, rheology modifiers, and fillers known in the art.

[0030] Isocyanate Prepolymer The isocyanate prepolymer of the present disclosure comprises the reaction product of a polyisocyanate and a non-dimer acid-based polyester polyol. For various embodiments, the isocyanate prepolymer is the reaction product of 35 to 95 weight percent of a polyisocyanate and 65 to 5 weight percent of a non-dimer acid-based polyester polyol, where the weight percents are based on the total weight of the isocyanate prepolymer, and the weight percents of the polyisocyanate and the non-dimer acid-based polyester polyol do not total more than 100 weight percent. Preferably, the isocyanate prepolymer is the reaction product of 55 to 85 weight percent of a polyisocyanate and 45 to 15 weight percent of a non-dimer acid-based polyester polyol, where the weight percents are based on the total weight of the isocyanate prepolymer, and the weight percents of the polyisocyanate and the non-dimer acid-based polyester polyol do not total more than 100 weight percent. More preferably, the isocyanate prepolymer is the reaction product of 60% to 80% by weight of a polyisocyanate and 40% to 20% by weight of a non-dimer acid-based polyester polyol, the weight percents being based on the total weight of the isocyanate prepolymer, and the weight percents of the polyisocyanate and the non-dimer acid-based polyester polyol do not total more than 100% by weight.

[0031] Polyisocyanate The polyisocyanate may be chemically reacted with the non-dimer acid-based polyester polyol to form a prepolymer. Non-limiting examples of suitable polyisocyanates include aromatic isocyanates, aliphatic isocyanates, carbodiimide-modified polyisocyanates, and combinations thereof, each of which is described herein.

[0032] Non-limiting examples of suitable aromatic polyisocyanates include polymeric MDI and isomers of MDI, such as 4,4-MDI, 2,4-MDI, and 2,2'-MDI, or modified MDI, such as polycarbodiimide-modified diphenylmethane diisocyanate or allophanate-modified MDI, toluene diisocyanate, isomers of toluene-dipolyisocyanates (TDI), such as 2,4-TDI, 2,6-TDI, isomers of naphthalene dipolyisocyanates (NDI), such as 1,5-NDI, and combinations thereof.

[0033] Non-limiting examples of suitable aliphatic polyisocyanates include isomers of HDI, isophorone diisocyanate, IPDI, XDI, 4,4'-methylenedicyclohexyl diisocyanate, methylenebis-cyclohexyl isocyanate (hydrogenated MDI or HMDI) and other cycloaliphatic isocyanates such as cyclohexane diisocyanate, and combinations thereof.

[0034] In one embodiment, the polyisocyanate is selected from mono-polyisocyanates, di-polyisocyanates, tri-polyisocyanates, and combinations thereof. In a further embodiment, the polyisocyanate is a di-polyisocyanate. In one embodiment, the polyisocyanate is selected from MDI, TDI, HDI, and combinations thereof. In a further embodiment, the polyisocyanate is MDI. In one embodiment, the polyisocyanate is selected from carbodiimide-modified MDI, carbodiimide-modified TDI, carbodiimide-modified HDI, and combinations thereof. In a further embodiment, the polyisocyanate is carbodiimide-modified MDI.

[0035] For various embodiments, the polyisocyanate may be selected from the group consisting of polycarbodiimide-modified diphenylmethane diisocyanate, MDI, TDI, isophorone diisocyanate, 4,4'-methylenedicyclohexyl diisocyanate, polymeric methylene diphenyl diisocyanate, and combinations thereof. In one embodiment, the polyisocyanate is polycarbodiimide-modified diphenylmethane diisocyanate.

[0036] In one embodiment, the polyisocyanate has an NCO content of 10% or greater, preferably 15% or greater, and preferably 20% or greater. For various embodiments, the isocyanate prepolymer has an isocyanate content of 10% to 29% by weight, as measured according to ASTM D5155.

[0037] The polyisocyanate component contains 35% by weight to 95% by weight, preferably 45% by weight to 80% by weight, more preferably 55% by weight to 85% by weight, and even more preferably 60% by weight to 80% by weight of isocyanate prepolymer, based on the total weight of the isocyanate prepolymer.

[0038] Non-dimer acid-based polyester polyols A "non-dimer acid-based polyester polyol" is a polyester polyol containing units derived from a primary polyol, a non-dimer acid dicarboxylic acid, and an aliphatic monocarboxylic acid. In one embodiment, the non-dimer acid-based polyester polyol is the reaction product of (i) a primary polyol having a hydroxyl functionality of at least 3 and a weight average molecular weight of 800 g / mol or less, (ii) a C4 to C20 non-dimer acid dicarboxylic acid, and (iii) a C10 to C20 aliphatic monocarboxylic acid. For various embodiments, the aliphatic monocarboxylic acid and the primary polyol have a molar ratio of greater than 0.9:1 to 6.5:1 (monocarboxylic acid:primary polyol), and the aliphatic monocarboxylic acid is present in the isocyanate prepolymer in a range of greater than 7.2 wt% to 55 wt%, based on the total weight of the isocyanate prepolymer.

[0039] Non-dimer acid-based polyester polyols can be formed by reacting a primary polyol, a non-dimer acid dicarboxylic acid, and an aliphatic monocarboxylic acid, each of which is provided herein, where the reaction mixture comprises 10% to 30% by weight of the primary polyol, 5% to 30% by weight of the non-dimer acid dicarboxylic acid, and 50% to 75% by weight of the aliphatic monocarboxylic acid, with the total weight of the primary polyol, non-dimer acid dicarboxylic acid, and aliphatic monocarboxylic acid being 100%. Preferably, the reaction mixture comprises 15% to 27% by weight of the primary polyol, 10% to 25% by weight of the non-dimer acid dicarboxylic acid, and 50% to 75% by weight of the aliphatic monocarboxylic acid, with the total weight of the primary polyol, non-dimer acid dicarboxylic acid, and aliphatic monocarboxylic acid being 100%. Most preferably, the reaction mixture comprises 17% to 25% by weight of a primary polyol, 12% to 22% by weight of a non-dimer acid dicarboxylic acid, and 53% to 72% by weight of an aliphatic monocarboxylic acid, wherein the total weight of the reaction mixture comprising the primary polyol, the non-dimer acid dicarboxylic acid, and the aliphatic monocarboxylic acid is 100%.

[0040] For various embodiments, a reaction mixture containing a primary polyol, a non-dimer dicarboxylic acid, and an aliphatic monocarboxylic acid can be mixed while heating to a temperature of 90° C. to 250° C. The acid number of the reaction mixture is preferably less than 10, and a catalyst can be used in the reaction mixture. Suitable catalysts include, for example, titanium(IV) butoxide, tetra-n-butyl orthotitanate, and titanium(IV) tert-butoxide.

[0041] For various embodiments, the non-dimer acid-based polyester polyol has a hydroxyl functionality of 1.8 to 2.3. For various embodiments, the non-dimer acid-based polyester polyol has an acid number of 5 mg KOH / g or less, as measured according to ASTM D974.

[0042] The non-dimer acid-based polyester polyol component comprises 65% to 5% by weight, preferably 55% to 20% by weight, more preferably 45% to 15% by weight, and even more preferably 40% to 20% by weight of isocyanate prepolymer, based on the total weight of the isocyanate prepolymer.

[0043] Primary Polyols For various embodiments, the primary polyol has a functionality of at least 3 and a weight average molecular weight of 800 g / mol or less. For various embodiments, the primary polyol is selected from the group consisting of glycerol, diglycerol, triglycerol, trimethylolpropane, di(trimethylolpropane), pentaerythritol, dipentaerythritol, tripentaerythritol, sorbitol, derivatives thereof such as alkoxylates, or combinations thereof. The polyol may comprise two or more embodiments disclosed herein.

[0044] Non-dimeric dicarboxylic acids Non-limiting examples of suitable non-dimer acid dicarboxylic acids include fatty acids, aromatic acids, and combinations thereof. Preferably, the non-dimer acid dicarboxylic acid is a C4-C20 non-dimer acid dicarboxylic acid. More preferably, the non-dimer acid dicarboxylic acid is a C4-C10 non-dimer acid dicarboxylic acid. Non-limiting examples of aromatic dicarboxylic acids suitable for use as non-dimer acid dicarboxylic acids include phthalic acid, isophthalic acid, and terephthalic acid. Non-limiting examples of aliphatic dicarboxylic acids suitable for use as non-dimer acid dicarboxylic acids include cyclohexanedicarboxylic acid, adipic acid, azelaic acid, sebacic acid, glutaric acid, maleic acid, fumaric acid, itaconic acid, suberic acid, 2-methylsuccinic acid, 3,3-diethylglutaric acid, and 2,2-dimethylsuccinic acid. As used herein, the term "acid" also includes any anhydrides of the acid. Saturated aliphatic and / or aromatic acids, such as adipic acid or isophthalic acid, are also suitable for use as the non-dimer dicarboxylic acid. For various embodiments, the non-dimer dicarboxylic acid is selected from the group consisting of adipic acid, isophthalic acid, and combinations thereof.

[0045] In one embodiment, the non-dimer acid dicarboxylic acid has 4, or 5, or 6-7, or 8, or 9, or 10 carbon atoms. In another embodiment, the non-dimer acid dicarboxylic acid has 4-10 carbon atoms, or 6-8 carbon atoms. In a further embodiment, the non-dimer acid dicarboxylic acid has 8 carbon atoms.

[0046] The non-dimer dicarboxylic acid may comprise two or more embodiments disclosed herein.

[0047] Aliphatic monocarboxylic acids For various embodiments, the aliphatic monocarboxylic acid is a C10 to C20 aliphatic monocarboxylic acid. Preferably, the aliphatic monocarboxylic acid is a C12 to C18 aliphatic monocarboxylic acid. For various embodiments, the aliphatic monocarboxylic acid may be selected from the group consisting of oleic acid, stearic acid, lauric acid, and combinations thereof. The non-dimer acid may comprise two or more embodiments disclosed herein.

[0048] Optional Additives In one embodiment, the isocyanate prepolymer of the present disclosure comprises the reaction product of a polyisocyanate, a non-dimer acid-based polyester polyol, and optional additives. Non-limiting examples of suitable optional additives include adhesion promoters, chain extenders, catalysts, and combinations thereof. A non-limiting example of a suitable adhesion promoter is aminosilane. Non-limiting examples of suitable chain extenders include glycerin, trimethylolpropane, diethylene glycol, propanediol, 2-methyl-1,3-propanediol, and combinations thereof. Non-limiting examples of suitable catalysts include tetra-n-butyl titanate, zinc sulfate, organotin catalysts, and combinations thereof. The optional additives may comprise two or more embodiments disclosed herein. In one embodiment, the reaction mixture excludes a chain extender.

[0049] The isocyanate prepolymer may optionally contain plasticizers, flame retardants, adhesion promoters, rheology modifiers, fillers, etc. Plasticizers such as diisononyl phthalate help reduce skinning that builds up during application of the isocyanate prepolymer.

[0050] Flame retardants such as isopropylated phenol phosphate can help improve fire resistance. Traditional adhesion promoters such as epoxy silanes can also be used. Rheology modifiers such as fumed silica are often included in adhesive compositions to provide thixotropic properties to suit various application needs. In isocyanate prepolymers, fumed silica with a hydrophobic surface treatment is often used as a rheology modifier. Fillers are added to adhesive compositions to improve mechanical strength and reduce costs. Fillers may be selected from silica, CaCO3, kaolin, and talc, among others known in the art.

[0051] The mixture for preparing the reaction product of (i) a polyisocyanate and (ii) a non-dimer acid-based polyester polyol typically comprises, based on the total weight of the mixture for preparing the reaction product of (i) a polyisocyanate and (ii) a non-dimer acid-based polyester polyol, 60% to 95% by weight, preferably 65% ​​to 85% by weight, and more preferably 70% to 80% by weight of an aromatic isocyanate and 5% to 40% by weight, preferably 15% to 35% by weight, and more preferably 20% to 30% by weight of a non-dimer acid-based polyester polyol.

[0052] The isocyanate prepolymer typically comprises 30 wt% to 100 wt%, preferably 35 wt% to 95 wt%, more preferably 40 wt% to 90 wt%, even more preferably 40 wt% to 80 wt%, or 50 wt% to 75 wt%, or 60 wt% to 75 wt%, of a reaction product of (i) a polyisocyanate and (ii) a non-dimer acid-based polyester polyol, optionally 0 wt% to 20 wt%, preferably 1 wt% to 10 wt%, more preferably 0.5 wt% to 8 wt%, even more preferably 1 wt% to 5 wt%, or 2 wt% to 4 wt%, of a plasticizer, based on the total weight of the isocyanate prepolymer. more preferably 0.5% to 8% by weight, even more preferably 0.8% to 5% by weight, or 1% to 3% by weight of a flame retardant; 0% to 10%, preferably 1% to 8% by weight, more preferably 0.5% to 6% by weight, even more preferably 0.8% to 5% by weight, or 1% to 4% by weight of an adhesion promoter; 0% to 10% by weight, preferably 0.5% to 8% by weight, even more preferably 1% to 5% by weight, or 2% to 4% by weight of a rheology modifier; and 0% to 70% by weight, preferably 5% to 65% by weight, more preferably 10% to 50% by weight, even more preferably 18% to 45% by weight, or 20% to 40% by weight, or 20% to 30% by weight of a filler.

[0053] Polyurethane adhesive The polyurethane adhesive is solvent-free or substantially solvent-free. In one embodiment, the polyurethane adhesive contains optional conventional additives. The optional additives can be any of the optional additives disclosed herein, such as plasticizers, chain extenders, flame retardants, adhesion promoters, rheology modifiers, fillers, moisture scavengers, catalysts, etc.

[0054] The polyurethane adhesive is formed by mixing the polyol component and the isocyanate prepolymer under conditions suitable to react the -NCO groups of the isocyanate prepolymer with the hydroxyl groups of the polyol component. In one embodiment, the polyol component and the isocyanate prepolymer are combined and mixed in a static or dynamic mixer at a temperature between 15°C and 55°C.

[0055] Isocyanate Index or ("NCO Index") is the molar ratio of isocyanate groups in the isocyanate prepolymer to the amount of hydroxyl groups in the polyol component. Isocyanate groups can be measured according to ASTM D2572. NCO Index is calculated according to the following equation (2):

[0056]

number

[0057] In one embodiment, the polyurethane adhesive has an NCO index of 1.00 or 1.05 or 1.10 or 1.15 to 1.85 or 1.60 or 1.50 or 1.40. In another embodiment, the polyurethane adhesive has an NCO index of 1.05 to 1.85, or 1.10 to 1.60, or 1.15 to 1.50, or 1.15 to 1.40.

[0058] In one embodiment, the polyurethane adhesive comprises a polyol component and an isocyanate prepolymer in a volume ratio of isocyanate prepolymer:polyol component of 120:100 to 80:100, or 115:100 to 90:100, or 110:100 to 95:100, or 105:100 to 98:100. The polyurethane adhesive may comprise two or more embodiments disclosed herein.

[0059] multilayer structure The present disclosure provides a multilayer structure. The multilayer structure includes a first substrate, a second substrate, and an adhesive layer between the first substrate and the second substrate. The adhesive layer is formed from a polyurethane adhesive provided herein. The first substrate and the second substrate can be the same or different. Any reference herein to a "substrate" is understood to refer to the first substrate and the second substrate individually and / or collectively.

[0060] A non-limiting example of a suitable substrate is a film. The film may be a monolayer film or a multilayer film. A multilayer film may include two layers, or three or more layers. In one embodiment, the film is a monolayer film having one and only one layer. In one embodiment, the film includes a layer containing a component selected from an ethylene-based polymer (PE), a propylene-based polymer (PP), a polyamide (such as nylon), a polyester, an ethylene vinyl alcohol (EVOH) copolymer, a polyethylene terephthalate (PET), an ethylene vinyl acrylate (EVA) copolymer, an ethylene methyl acrylate copolymer, an ethylene ethyl acrylate copolymer, an ethylene butyl acrylate copolymer, an ethylene acrylic acid copolymer, an ethylene methacrylic acid copolymer, an ionomer of ethylene acrylic acid, an ionomer of methacrylic acid, a maleic anhydride-grafted ethylene-based polymer, a polylactic acid (PLA), a polystyrene, a metal foil, a cellulose, a cellophane, a nonwoven fabric, and combinations thereof. Each layer of the multilayer film may be formed from the same components or from different components.

[0061] In one embodiment, the film includes a layer containing a metal foil. A non-limiting example of a suitable metal foil is aluminum foil.

[0062] In one embodiment, the film is a monolayer film having a single layer that is an ethylene-based polymer layer. In a further embodiment, the film is a monolayer film having a single layer that is a polyethylene layer.

[0063] Substrates, and also films, are continuous structures with two opposing surfaces.

[0064] In one embodiment, the substrate has a thickness of 5 μm, or 10 μm, or 12 μm, or 15 μm, or 20 μm, or 21 μm to 23 μm, or 24 μm, or 25 μm, or 30 μm, or 35 μm, or 40 μm, or 45 μm, or 50 μm, or 100 μm, or 150 μm, or 200 μm, or 250 μm, or 300 μm, or 350 μm, or 400 μm, or 450 μm, or 500 μm.

[0065] In one embodiment, the substrate excludes cellulosic substrates such as paper and wood.

[0066] In one embodiment, the first substrate is a monolayer film having a single layer that is a PE layer, and the second substrate is a film having a layer that is a metal foil layer.

[0067] The film may comprise two or more embodiments disclosed herein. The first substrate may comprise two or more embodiments disclosed herein. The second substrate may comprise two or more embodiments disclosed herein.

[0068] The polyurethane adhesive is applied between the first and second substrates using, for example, a Nordmeccanica Labo Combi 400 laminator. Non-limiting examples of suitable application methods include brushing, pouring, spraying, coating, rolling, sprinkling, and injecting. In one embodiment, the polyurethane adhesive is applied between the first and second substrates at a temperature of 20°C, 30°C, or 40°C to 50°C, 60°C, 70°C, 80°C, or 90°C.

[0069] In one embodiment, the polyurethane adhesive is applied uniformly between a first substrate and a second substrate. A "uniform application" is a layer of composition that is continuous (not intermittent) across the surface of the substrate and that is the same or substantially the same thickness across the surface of the substrate. In other words, a composition that is applied uniformly to a substrate is in direct contact with the substrate surface and is coextensive with the substrate surface.

[0070] In one embodiment, the polyurethane adhesive is cured in an oven at a temperature of 10° C., 20° C., or 35° C. to 40° C., or 45° C., or 50° C. In one embodiment, the polyurethane adhesive is cured at a temperature of 20° C. to 30° C., preferably 25° C., for a period of 1 to 2 days, or 4 days, or 7 days, or 10 days.

[0071] In one embodiment, the first substrate is a monolayer film having a single layer that is a metal foil layer, the second substrate is a monolayer film having a single layer that is a metal foil layer, and the multilayer structure has a lap shear strength of 7 MPa or 7.5 MPa or 8 MPa to 15 MPa or 13 MPa or 12 MPa, and / or a cross tensile strength of 6.5 MPa or 7.0 MPa or 7.5 MPa to 15 MPa or 13 MPa or 12 MPa.

[0072] In one embodiment, the first substrate is a monolayer film having a single layer that is a metal foil layer, the second substrate is a film having a layer that is a metal foil layer, and the multilayer structure has an average lap joint adhesive shear strength at the 3σ level of >7 MPa, or 7.5 MPa, or 8 MPa to 15 MPa, or 13 MPa or 12 MPa, and an average butt joint adhesive tensile strength at the 3σ level of 6.5 MPa, or 6.7, or 7.0 MPa, or 7.5 MPa to 15 MPa, or 13 MPa or 12 MPa.

[0073] Various embodiments of the present disclosure also include batteries comprising the polyurethane adhesives of the present disclosure, including, for example, lithium ion batteries known in the art.

[0074] By way of example, and not limitation, some embodiments of the present disclosure will now be described in detail in the following examples. [Example]

[0075] The following examples are provided for illustrative purposes only and are not intended to define or limit the embodiments in any way. In the Inventive Examples (IE) and Comparative Examples (CE), various terms and names for materials are used, such as, for example:

[0076] [Table 1]

[0077] Synthesis of dimer acid / 2-methyl-1,3-propanediol-based polyester polyol-1 (DMP-PE). 50 grams (g) of 2-methyl-1,3-propanediol and 233.8 g of dimer acid (ATUREX® 1001) were added to a 500 ml glass reactor and mixed thoroughly. The mixture was heated to 100°C. Once the raw materials became liquid, stirring was initiated. The temperature was controlled appropriately and monitored throughout the process. If the temperature at the top of the glass cooler rose above 103°C, cooling of the reactor was initiated as soon as possible. Once the reaction temperature rose to 220°C and the top temperature had fallen below 100°C, vacuum was initiated and slowly increased to 30 mmHg over 30 minutes. The acid value was checked every 30 minutes. The catalyst Tyzor® TBT is added until the acid number of the reaction mixture is less than 10, and then the reaction system is maintained under a vacuum of 30 mmHg for more than 1 hour until the OH number reaches the theoretical value. The resulting mixture is cooled to 60-70°C, and the final product is recovered as DMP-PE.

[0078] Synthesis of adipic acid / 2-methyl-1,3-propanediol-based polyester polyol (AMP-PE). 100 g of 2-methyl-1,3-propanediol and 146.4 g of adipic acid were reacted as described for (DFMP-PE). The final product was recovered as AMP-PE.

[0079] Synthesis of adipic acid / trimethylolpropane / oleic acid-based polyester polyol (ATO-PE-1). 97.4 g of trimethylolpropane, 80.5 g of adipic acid, and 205.0 g of oleic acid were reacted as described for (DFMP-PE). The final product was collected as ATO-PE-1.

[0080] Synthesis of adipic acid / trimethylolpropane / oleic acid-based polyester polyol (ATO-PE-2). 101.4 g of trimethylolpropane, 83.8 g of adipic acid, and 198.0 g of oleic acid were reacted as described for (DFMP-PE). The final product was collected as ATO-PE-2.

[0081] Synthesis of adipic acid / 2-methyl-1,3-propanediol / trimethylolpropane / oleic acid-based polyester polyol (ATO-PE-3). 69.9 g of trimethylolpropane, 126.7 g of adipic acid, 147.1 g of oleic acid, and 47.0 g of 2-methyl-1,3-propanediol were reacted as described for (DFMP-PE). The final product was recovered as ATO-PE-3.

[0082] Synthesis of adipic acid / trimethylolpropane / oleic acid / stearic acid-based polyester polyol (ATOS-PE). 95.5 g of trimethylolpropane, 78.4 g of adipic acid, 100.5 g of oleic acid, and 101.2 g of stearic acid were reacted as described for (DFMP-PE). The final product was recovered as ATOS-PE.

[0083] Synthesis of adipic acid / pentaerythrotol / oleic acid-based polyester polyol (APO-PE). 64.9 g of pentaerythritol, 44.0 g of adipic acid, and 269.1 g of oleic acid were reacted as described for (DFMP-PE). The final product was recovered as APO-PE.

[0084] Synthesis of adipic acid / isophthalic acid / trimethylolpropane / oleic acid-based polyester polyol (AITO-PE). 96.0 g of trimethylolpropane, 39.5 g of adipic acid, 44.9 g of isophthalic acid, and 202.0 g of oleic acid were reacted as described for (DFMP-PE). The final product was recovered as AITO-PE.

[0085] Synthesis of phosphoric acid-modified polyols The synthesis of the phosphoric acid-modified polyol is described in Example 5 of WO 2015 / 168670 A1, which is incorporated herein by reference in its entirety. A 1-liter (L) multi-neck round-bottom flask was oven-dried and flushed with dry N for 30 minutes, then charged with VORANOL™ CP450 polyether polyol (150 g) and placed under a 70 mL / min N sweep. A syringe was charged with 115% polyphosphoric acid (PPA) (4 g, Aldrich Chemical Co.). The PPA was added dropwise to the polyether polyol with vigorous stirring. Minimal temperature increase was observed. The reactor contents were heated to 100°C for 1 hour and then cooled to 45°C. ISONATE™ 125M polyisocyanate (50 g) was added. The reaction exotherm caused the temperature to rise to approximately 95°C. There was also an increase in viscosity and the development of a yellow color. The reactor was then brought to 65°C and ethyl acetate (40 g) was added to reduce the viscosity and improve stirring. After 1 hour, the reactor was cooled and the contents were packaged (viscosity: 42,750 mPa.s).

[0086] Synthesis of Castor Oil Polyurethane Polyol (COP Polyol): COP polyol was synthesized in a 1,000 ml glass reactor as a conventional polyurethane prepolymer preparation process. 12 g of ISONATE™ OP 50 was added to the reactor and maintained at 60°C under nitrogen protection. 44 g of castor oil and 44 g of VORANOL™ P 400 were then added to the reactor and mixed with the ISONATE™ OP 50. The temperature was slowly increased to 80°C and maintained for 2 hours. The resulting COP polyol (vegetable oil polyurethane polyol) was placed in a nitrogen-protected, tightly sealed container for further use.

[0087] Synthesis of NCO-terminated prepolymer of DMP-PE (Pre-DMP): 75 g of ISONATE™ 143L was charged into a 1,000 ml glass reactor and maintained at 60°C under nitrogen protection. Then, 25 g of DMP-PE was charged into the reactor and mixed with ISONATE™ 143L. The temperature was slowly increased to 80°C and maintained for 2 to 3 hours until the NCO content reached the theoretical value. The resulting Pre-DMP was charged into a well-sealed container under nitrogen protection for further application.

[0088] Synthesis of NCO-terminated prepolymer of AMP-PE (Pre-AMP): 75 g of ISONATE™ 143L was charged into a 1,000 ml glass reactor and maintained at 60°C under nitrogen protection. Then, 25 g of AMP-PE was charged into the reactor and mixed with ISONATE™ 143L. The temperature was slowly increased to 80°C and maintained for 2 to 3 hours until the NCO content reached the theoretical value. The resulting Pre-AMP was charged into a well-sealed container under nitrogen protection for further application.

[0089] Synthesis of NCO-terminated prepolymer of ATO-PE-1 (Pre-ATO1): 75 g of ISONATE™ 143L was charged into a 1,000 ml glass reactor and maintained at 60°C under nitrogen protection. Then, 25 g of ATO-PE-1 was charged into the reactor and mixed with ISONATE™ 143L. The temperature was slowly increased to 80°C and maintained for 2 to 3 hours until the NCO content reached the theoretical value. The resulting Pre-ATO1 was charged into a well-sealed container under nitrogen protection for further application.

[0090] Synthesis of NCO-terminated prepolymer of ATO-PE-2 (Pre-ATO2): 75 g of ISONATE™ 143L was charged into a 1,000 ml glass reactor and maintained at 60°C under nitrogen protection. Then, 25 g of ATO-PE-2 was charged into the reactor and mixed with ISONATE™ 143L. The temperature was slowly increased to 80°C and maintained for 2 to 3 hours until the NCO content reached the theoretical value. The resulting Pre-ATO2 was charged into a well-sealed container under nitrogen protection for further application.

[0091] Synthesis of NCO-terminated prepolymer of ATO-PE-3 (Pre-ATO3): 75 g of ISONATE™ 143L was charged into a 1,000 ml glass reactor and maintained at 60°C under nitrogen protection. Then, 25 g of ATO-PE-3 was charged into the reactor and mixed with ISONATE™ 143L. The temperature was slowly increased to 80°C and maintained for 2 to 3 hours until the NCO content reached the theoretical value. The resulting Pre-ATO3 was charged into a well-sealed container under nitrogen protection for further application.

[0092] Synthesis of NCO-terminated prepolymer of ATOS-PE (Pre-ATOS): 75 g of ISONATE™ 143L was charged into a 1,000 ml glass reactor and maintained at 60°C under nitrogen protection. Then, 25 g of ATOS-PE was charged into the reactor and mixed with ISONATE™ 143L. The temperature was slowly increased to 80°C and maintained for 2 to 3 hours until the NCO content reached the theoretical value. The resulting Pre-ATOS was charged into a well-sealed container under nitrogen protection for further application.

[0093] Synthesis of NCO-terminated prepolymer of APO-PE (Pre-APO): 75 g of ISONATE™ 143L was charged into a 1,000 ml glass reactor and maintained at 60°C under nitrogen protection. Then, 25 g of APO-PE was charged into the reactor and mixed with ISONATE™ 143L. The temperature was slowly increased to 80°C and maintained for 2 to 3 hours until the NCO content reached the theoretical value. The resulting Pre-APO was charged into a well-sealed container under nitrogen protection for further application.

[0094] Synthesis of NCO-terminated prepolymer of AITO-PE (Pre-AITO): 75 g of ISONATE™ 143L was charged into a 1,000 ml glass reactor and maintained at 60°C under nitrogen protection. Then, 25 g of AITO-PE was charged into the reactor and mixed with ISONATE™ 143L. The temperature was slowly increased to 80°C and maintained for 2 to 3 hours until the NCO content reached the theoretical value. The resulting Pre-AITO was charged into a well-sealed container under nitrogen protection for further application.

[0095] The invention examples (IE) were designed in two steps: (1) isocyanate prepolymers (Part A, Part B) capable of meeting the moisture resistance requirements, summarized in Table 2; and (2) adhesive examples, including Part A and Part B, summarized in Table 3.

[0096] CE-A exhibited good hydrophobicity, but the cost and cycle time for preparing the polyester polyol were high (20 hours). CE-B exhibited poor moisture resistance (only 7 hours). IE-1 exhibited good moisture resistance (14 hours) due to the introduction of aliphatic monocarboxylic acid (e.g., 10.1 wt. % based on the iso component), and compared to CE-A, it required a shorter time (11 hours) to prepare the polyester, resulting in lower costs. CE-C showed failure in prepolymer synthesis due to the decrease in the molar ratio between the aliphatic monocarboxylic acid and the low molecular weight, high functionality polyol from 1.00 (IE-1) to 0.93. Therefore, CE-C provides a boundary for the molar ratio between the aliphatic monocarboxylic acid and the polyol. CE-D showed poor moisture resistance of the isocyanate prepolymer due to the reduction of the aliphatic monocarboxylic acid incorporation from 10.1 wt. % based on the isocyanate prepolymer (IE-1) to 7.2 wt. % based on the isocyanate prepolymer. CE-D therefore provides a boundary for the weight ratio of aliphatic monocarboxylic acid in the isocyanate prepolymer.

[0097] IE-2, IE-3 and IE-4 all exhibit good moisture resistance, a short time for preparing the polyester polyol, and low raw material costs for the polyester polyol due to the significant content of long-chain and aliphatic monocarboxylic acid (9.9% by weight to 11.2% by weight based on the isocyanate prepolymer) and the molar ratio between the aliphatic monocarboxylic acid and the polyol (1.00 to 2.00).

[0098] [Table 2]

[0099] The adhesive formulations are summarized in Table 3, along with details of Part A and corresponding examples of Part B. The volumetric mix ratios and stoichiometric ratios were calculated and are listed in Table 3. CE-E exhibited poor lap shear strength (10.14 MPa < 10.5 MPa) due to the introduction of dimer acid into the isocyanate of applied CE-A. CE-F exhibited increased and sufficient lap shear strength (10.87 MPa > 10.5 MPa) due to the replacement of dimer acid with adipic acid, but the moisture resistance was unacceptable due to the application of the isocyanate prepolymer of CE-B. CE-G exhibited sufficient lap shear strength (11.72 MPa > 10.5 MPa) due to the replacement of dimer acid with adipic acid, but the moisture resistance of applied isocyanate prepolymer CE-D was poor due to the reduced content of long-chain, aliphatic monocarboxylic acid. IE-5 exhibited good lap shear strength (11.91 MPa > 10.5 MPa) due to the replacement of dimer acid with adipic acid and the good humidity resistance of the applied isocyanate prepolymer IE-1. The use of an aliphatic monocarboxylic acid (incorporation of 10.1 wt.% based on the isocyanate component) resulted in a short time for preparing the polyester polyol and a low polyester polyol cost. Comparing IE-5 with CE-H, the omission of the phosphoric acid-modified polyol resulted in poor lap shear strength (9 MPa << 10.5 MPa). Therefore, the phosphoric acid-modified polyol is useful for achieving high lap shear strength. Comparing IE5 with CE-I, the omission of the COP polyol (vegetable oil polyurethane polyol) resulted in poor lap shear strength (10.24 MPa < 10.5 MPa). Therefore, to achieve high lap shear strength, vegetable oil polyurethane polyol should be present in the formulation.IE-6, IE-7, and IE-8, which incorporated IE-2, IE-3, and IE-4 isocyanate prepolymers, exhibited good lap shear strength (12.00 MPa to 14.29 MPa > 10.5 MPa) due to the inclusion of phosphoric acid-modified polyol and COP polyol (vegetable oil polyurethane polyol). However, the applied isocyanate prepolymers exhibited good moisture resistance due to the significant content of aliphatic monocarboxylic acid (9.9 wt% to 11.2 wt% based on the isocyanate prepolymer) and the molar ratio between aliphatic monocarboxylic acid and high-functionality short-chain polyol (1.00 to 2.00). The time required to prepare the polyester polyol was short, and the raw material cost of the polyester polyol was low.

[0100] [Table 3]

[0101] Experimental procedure The isocyanate prepolymer (part) was prepared according to the following procedure: Step 1 - Charge the NCO-terminated prepolymer into a container, then add the other liquid ingredients (e.g., DINP, KH560). Step 2 - Apply vacuum and mix for 30 minutes at medium agitation speed. Step 3 - Charge the CaCO3 into the container, add the powder, then apply vacuum and mix at high speed for 30 minutes. Step 4 - Charge the AEROSIL® R974 into the container, add the powder, then apply vacuum and mix at high speed for 1 hour. Step 5 - Set the temperature bath to 80°C and continue mixing for 30 minutes at medium to low agitation speed to maintain the temperature. Step 6 - Set the temperature bath to 20°C and allow to cool to below 40°C.

[0102] The tack-free time was tested according to the procedure (ASTM C679-03). 10 g of isocyanate prepolymer (part B) was placed in a 50 ml plastic beaker and placed in an oven at 45% relative humidity and 23°C. Time recording was started. Periodically, the beaker was removed and the surface of isocyanate prepolymer B was lightly touched with a plastic rod. As the reaction of the isocyanate prepolymer with moisture progressed, the surface viscosity increased. When the surface of the isocyanate prepolymer was no longer tacky, time recording was stopped. This period was recorded as the tack-free time of the isocyanate prepolymer.

[0103] The polyol component (Part A) is prepared according to the following procedure: Step 1 - Add castor oil, phosphate-modified polyol, COP polyol (vegetable oil polyurethane polyol), Voranol™ CP450, and 1,4-BDO to a container. Step 2 - Heat the mixture to 80°C, apply vacuum, and mix at medium speed for 1 hour to degas. Step 3 - Add CaCO3 to the container, add powder, apply vacuum, and mix at high speed for 15 minutes. Step 4 - Add molecular sieve 3A to the container, add powder, apply vacuum, and mix at high speed for 15 minutes. Step 5 - Add AEROSIL® R974 to the container, add powder, apply vacuum, and mix at high speed for 1 hour. Step 6 - Cool to below 40°C.

[0104] Test Method Acid number was measured according to ASTM D974.

[0105] The lap joint test coupons were prepared as follows: (1) The substrate was made of 3003 aluminum alloy with dimensions of 25 mm x 12.5 mm. (2) The substrate surface was wiped clean with ethanol. (3) A 25 mm x 12 mm joint area was masked using pressure-sensitive tape. (4) Part A and Part B of the adhesive were mixed and placed in a speed mixer at 1,000 rpm for 1 minute to ensure complete mixing. (5) 0.5 g to 1.5 g of adhesive was applied to the joint area of ​​the substrate. Two 0.2 mm diameter copper wires were inserted to control the adhesive thickness. (6) Another masked substrate was stacked along the length so that the same joint area was in head-to-head contact. Two clippers were placed side by side to press the joint surfaces together. (7) The adhesive was allowed to cure at 25°C for 7 days.

[0106] Butt joint test coupons were prepared according to the following procedure: (1) A substrate was made from 3003 aluminum alloy with dimensions of 60 mm height and 15 mm diameter. (2) The substrate surface was wiped clean with ethanol. (3) Part A and Part B of the adhesive were mixed and placed in a speed mixer at 1,000 rpm for 1 minute to ensure complete mixing. (4) 0.5 g to 1 g of adhesive was applied to the flat surface of the substrate. Two 0.25 mm diameter copper wires were inserted to control the adhesive thickness. (5) Another cleaned substrate was stacked with its flat surfaces joined together. The stacked substrates were kept vertical, allowing gravity to hold the joining surfaces in place. (6) The adhesive was allowed to cure for 7 days at 25°C.

[0107] The test coupons were assembled on the fixture of an Instron testing machine (Model: Instron 5566) and tested for shear strength of the lap joint and tensile strength of the butt joint at a strain rate of 5 mm / min.

Claims

1. 35 weight percent (wt %) to 95 wt % of a polyisocyanate; an isocyanate prepolymer comprising the reaction product with 65% to 5% by weight of a non-dimer acid-based polyester polyol, said weight percent being based on the total weight of said isocyanate prepolymer, and the weight percents of said polyisocyanate and said non-dimer acid-based polyester polyol do not total more than 100% by weight; an isocyanate prepolymer, wherein the non-dimer acid-based polyester polyol comprises the reaction product of a primary polyol having a hydroxyl functionality of at least 3 and a weight average molecular weight of 800 g / mol or less, a C4 to C20 non-dimer acid dicarboxylic acid, and a C10 to C20 aliphatic monocarboxylic acid, wherein the aliphatic monocarboxylic acid and the primary polyol have a molar ratio of greater than 0.9:1 to 6.5:1 (monocarboxylic acid:primary polyol), and the aliphatic monocarboxylic acid is present in the isocyanate prepolymer in an amount ranging from greater than 7.2 wt% to 55 wt%, based on the total weight of the isocyanate prepolymer; 20% to 80% by weight of a hydrophobic polyol; 3% to 15% by weight of a phosphoric acid-modified polyol; a polyol component comprising: 10 wt. % to 30 wt. % of a vegetable oil polyurethane polyol, said wt. % being based on the total weight of said polyol component, and wherein the combined wt. % of said hydrophobic polyol, said phosphoric acid-modified polyol, and said vegetable oil polyurethane polyol does not exceed 100 wt. %; Polyurethane adhesives, including:

2. The polyurethane adhesive of claim 1, wherein the non-dimer acid-based polyester polyol has a hydroxyl functionality of 1.8 to 2.

3.

3. 10. The polyurethane adhesive of claim 1, wherein the non-dimer acid-based polyester polyol has an acid number of 5 mg KOH / g or less as measured according to ASTM D974.

4. 10. The polyurethane adhesive of claim 1, wherein the aliphatic monocarboxylic acid is selected from the group consisting of oleic acid, stearic acid, lauric acid, and combinations thereof.

5. 10. The polyurethane adhesive of claim 1, further comprising 5% to 20% by weight of a polyether polyol.

6. The polyurethane adhesive of claim 1 , wherein the hydrophobic polyol is castor oil.

7. 10. The polyurethane adhesive of claim 1 having an isocyanate index of 1.05 to 1.

85.

8. 10. The polyurethane adhesive of claim 1, wherein the non-dimer dicarboxylic acid is selected from the group consisting of adipic acid, isophthalic acid, and combinations thereof.

9. a first substrate; a second substrate; and an adhesive layer between the first substrate and the second substrate, the adhesive layer being formed from the polyurethane adhesive of any one of claims 1 to 8, wherein the first substrate is a monolayer film having a single layer that is a metal foil layer, and the second substrate is a monolayer film having a single layer that is a metal foil layer.

10. A battery comprising the polyurethane adhesive of any one of claims 1 to 8.