Two-component polyurethane adhesive as well as preparation method and application thereof

Abstract

The invention relates to a two-component polyurethane adhesive as well as a preparation method and application thereof. The double-component polyurethane adhesive comprises a component A and a component B, the component A is modified isocyanate, the end group of the modified isocyanate is an isocyanate group, and the component B is a polyhydroxy compound. The component A and the component B are mixed according to the molar ratio R of-NCO groups in the component A to-OH groups in the component B being (1.5-2.2): 1, and the obtained adhesive meets the following conditions: the ratio of the integral area of a 6.5 ppm to 10.0 ppm region in a 1H-NMR spectrogram of the obtained adhesive to the total integral area is 4%-30%. The two-component polyurethane adhesive disclosed by the invention has good adhesion at a high temperature.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesives, in particular to a two-component polyurethane adhesive and a preparation method and application thereof. Background Art

[0002] As living standards improve, people are paying more and more attention to health and environmental protection. The adhesives industry is shifting away from solvent-based adhesives, which are known to pollute the environment and harm the body, toward solvent-free and environmentally friendly water-based adhesives. Water-based adhesives, due to their high surface tension and low volatility, have low peel strength, high production costs, and a narrow range of applications. Compared to water-based adhesives, solvent-free two-component adhesives achieve coating and bonding without the use of any solvents during the preparation process. They offer superior overall performance, are economical and environmentally friendly, and offer safe, efficient production and high product quality.

[0003] Solvent-free two-component adhesives primarily include solvent-free two-component polyurethane adhesives. As their applications expand, higher requirements are placed on their adhesion at high temperatures. Therefore, developing a two-component polyurethane adhesive with excellent adhesion at high temperatures is an urgent challenge. Summary of the Invention

[0004] Based on this, it is necessary to provide a two-component polyurethane adhesive with good adhesion at high temperatures, a preparation method and an application.

[0005] In a first aspect of the present application, a two-component polyurethane adhesive is provided, comprising component A and component B;

[0006] The component A is a modified isocyanate, the terminal group of the modified isocyanate is an isocyanate group, the component B is a polyhydroxy compound, and the molar ratio R of the -NCO group in the component A to the -OH group in the component B is (1.5-2.2):1. The adhesive obtained after the preparation meets the following conditions: 1 The integrated area of ​​the 6.5 ppm to 10.0 ppm region in the H-NMR spectrum accounts for 4% to 30% of the total integrated area.

[0007] In the above two-component polyurethane adhesive, the adhesive obtained after the component A and the component B are mixed in a specific molar ratio is 1 The integrated area of ​​the 6.5ppm~10.0ppm region in the H-NMR spectrum accounts for 1Controlling the ratio of the total integrated area in the H-NMR spectrum within the above-mentioned specific range not only enables the adhesive to have higher intermolecular forces at high temperatures, thereby enabling it to have good cohesion at high temperatures, but also imparts it with good peel strength and improves interfacial adhesion, thereby improving the bonding performance of the polyurethane adhesive.

[0008] In some embodiments, the adhesive obtained after the preparation of the glue 1 The integrated area of ​​the 6.5 ppm to 10.0 ppm region in the H-NMR spectrum accounts for 13% to 26% of the total integrated area.

[0009] In some embodiments, the A component 1 The integral area of ​​the 6.5ppm~10.0ppm region in the H-NMR spectrum accounts for 6%~40% of the total integral area. 1 The integrated area of ​​the 6.5 ppm to 10.0 ppm region in the H-NMR spectrum accounts for 0.3% to 25% of the total integrated area.

[0010] In the first aspect of the present application, there is also provided a two-component polyurethane adhesive comprising component A and component B;

[0011] The component A is a modified isocyanate, the terminal group of the modified isocyanate is an isocyanate group, the component B is a polyhydroxy compound, and the terminal group of the component A is an isocyanate group. 1 The integral area of ​​the 6.5ppm~10.0ppm region in the H-NMR spectrum accounts for 6%~40% of the total integral area. 1 The integrated area of ​​the 6.5 ppm to 10.0 ppm region in the H-NMR spectrum accounts for 0.3% to 25% of the total integrated area.

[0012] In some embodiments, the A component 1 The proportion of the integrated area of ​​the 6.5 ppm to 10.0 ppm region in the H-NMR spectrum to the total integrated area is 15% to 40%; and / or,

[0013] The B component 1 The integrated area of ​​the 6.5 ppm to 10.0 ppm region in the H-NMR spectrum accounts for 11% to 25% of the total integrated area.

[0014] In some embodiments, the component A includes one or more of a polyisocyanate copolymer, a polyisocyanate biuret, and a polyol-modified isocyanate, and one or more of the polyisocyanate copolymers contains a conjugated group, and the conjugated group includes one or more of an aromatic group having 6 to 20 carbon atoms and an aldehyde group.

[0015] In some embodiments, the polyisocyanate copolymer is selected from one or more of an aromatic polyisocyanate copolymer, an aliphatic polyisocyanate copolymer and an alicyclic polyisocyanate copolymer; and / or,

[0016] The polyisocyanate biuret is selected from one or more of aromatic polyisocyanate biuret, aliphatic polyisocyanate biuret, and alicyclic polyisocyanate biuret; and / or,

[0017] The polyol in the polyol-modified isocyanate is selected from one or more of polyether polyols, polyester polyols, small molecule polyols, polycaprolactone polyols, polycarbonate polyols, polyether ester polyols, bio-based polyols, epoxy resins and acrylic polyols, wherein the small molecule polyol is a C2-C10 polyol.

[0018] In some embodiments, the small molecule polyol is selected from one or more of diethylene glycol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propylene glycol, 1,4-butanediol, 1,6-hexanediol, terephthalic acid methanol, neopentyl glycol, 1,3-butanediol, 2-ethyl-1,3-hexanediol, 1,2-octanediol, glycerol and trimethylolpropane; and / or,

[0019] The polycaprolactone polyol is a polyol obtained by ring-opening polymerization of caprolactone; and / or

[0020] The polycarbonate polyol is a polyol containing carbonate groups; and / or,

[0021] The polyetherester polyol is a polyol containing a polyether segment and an ester bond; and / or,

[0022] The bio-based polyol is selected from one or more of castor oil, soybean oil, palm oil, rosin ester and derivatives thereof; and / or,

[0023] The epoxy resin is one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, novolac epoxy resin, hydrogenated bisphenol A epoxy resin, hydrogenated bisphenol F epoxy resin, alicyclic epoxy resin, o-cresol epoxy resin, hydantoin epoxy resin, bisphenol S epoxy resin, bisphenol fluorene epoxy resin, polyurethane modified epoxy resin, rubber modified epoxy resin, and core-shell particle modified epoxy resin; and / or,

[0024] The acrylic ester polyol is prepared by polymerizing acrylic ester monomers, wherein the acrylic ester monomers include one or more of monofunctional acrylic ester monomers, difunctional acrylic ester monomers and trifunctional acrylic ester monomers.

[0025] In some embodiments, the polyol-modified isocyanate is prepared by reacting a polyol and a polyisocyanate-based compound;

[0026] The polyisocyanate compound is selected from one or more of aromatic polyisocyanates, aliphatic polyisocyanates and alicyclic polyisocyanates;

[0027] Optionally, the polyisocyanate-based compound is selected from one or more of toluene diisocyanate, diphenylmethane diisocyanate (MDI), liquefied MDI, naphthalene diisocyanate, p-phenylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, xylene diisocyanate, cyclohexane dimethylene diisocyanate, hexamethylene diisocyanate, and homopolymers of the aforementioned isocyanate monomers and biuret of the aforementioned isocyanate monomers.

[0028] In some embodiments, the B component includes one or more of small molecule polyols, polyether polyols, polyester polyols, polycaprolactone polyols, polyether ester polyols, polycarbonate polyols, bio-based polyols, epoxy resins, acrylate polyols and isocyanate-extended polyols, and one or more of them contains conjugated groups, and the conjugated groups include one or more of aromatic groups and aldehyde groups having 6 to 20 carbon atoms, and the small molecule polyol is a C2-C10 polyol.

[0029] In some embodiments, in the B component,

[0030] The small molecule polyol is selected from one or more of diethylene glycol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propylene glycol, 1,4-butanediol, 1,6-hexanediol, terephthalic acid methanol, neopentyl glycol, 1,3-butanediol, 2-ethyl-1,3-hexanediol, 1,2-octanediol, glycerol and trimethylolpropane; and / or,

[0031] The polyether polyol is selected from one or more hydroxyl-terminated oligomers of polypropylene oxide, propylene oxide ethylene oxide copolymer and polytetrahydrofuran; and / or,

[0032] The number average molecular weight of the polyether polyol is 400 to 2000; and / or,

[0033] The polyester polyol is a hydroxyl-terminated oligomer obtained by a high molecular weight condensation polymerization reaction of a dibasic acid and a polyol, wherein the dibasic acid is selected from one or more of adipic acid, isophthalic acid, terephthalic acid, phthalic anhydride and sebacic acid, and the polyol is selected from one or more of diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,3-butanediol, 2-ethyl-1,3-hexanediol, 1,2-octanediol, 1,8-octanediol, 2,5-dimethyl-2,5-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 3,6-octanediol, 2,2,4-trimethyl-1,3-pentanediol, glycerol and trimethylolpropane; and / or,

[0034] The number average molecular weight of the polyester polyol is 400 to 1000; and / or,

[0035] The polycaprolactone polyol is a polyol obtained by ring-opening polymerization of caprolactone; and / or

[0036] The polycarbonate polyol is a polyol containing carbonate groups; and / or,

[0037] The polyetherester polyol is a polyol containing a polyether segment and an ester bond; and / or,

[0038] The bio-based polyol is selected from one or more of castor oil, soybean oil, palm oil, rosin ester and derivatives thereof;

[0039] The epoxy resin is selected from one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, novolac epoxy resin, hydrogenated bisphenol A epoxy resin, hydrogenated bisphenol F epoxy resin, alicyclic epoxy resin, o-cresol epoxy resin, hydantoin epoxy resin, bisphenol S epoxy resin, bisphenol fluorene epoxy resin, polyurethane modified epoxy resin, rubber modified epoxy resin and core-shell particle modified epoxy resin; and / or,

[0040] The acrylic acid ester polyol is polymerized from acrylic acid ester monomers, wherein the acrylic acid ester monomers include one or more of monofunctional acrylic acid ester monomers, difunctional acrylic acid ester monomers and trifunctional acrylic acid ester monomers; and / or,

[0041] The isocyanate in the isocyanate-extended polyol is selected from one or more of toluene diisocyanate, diphenylmethane diisocyanate, liquefied MDI, naphthalene diisocyanate, p-phenylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, xylylene diisocyanate, cyclohexane dimethylene diisocyanate, hexamethylene diisocyanate and homopolymers of the aforementioned isocyanate monomers; and / or,

[0042] The polyol in the isocyanate-extended polyol is one or more of small molecule polyol, polyester polyol, polyether polyol and polycaprolactone polyol; optionally, the polyol in the isocyanate-extended polyol is one or more of polyester polyol and polyether polyol.

[0043] In some embodiments, the NCO mass content of the A component is 14% to 23%; and / or,

[0044] The hydroxyl value of the B component is 170 gKOH / g to 310 mgKOH / g.

[0045] In some embodiments, the ratio of the component A to the component B is based on a molar ratio R of -NCO groups in the component A to -OH groups in the component B of (1.5-2.2):1.

[0046] In a second aspect of the present application, a method for preparing a two-component polyurethane adhesive is provided, comprising the following steps:

[0047] The A component and the B component of the two-component polyurethane adhesive of the first aspect are prepared.

[0048] In a third aspect, the present application provides a cured adhesive, which is obtained by curing the two-component polyurethane adhesive provided in the first aspect.

[0049] The fourth aspect of the present application provides the use of the two-component polyurethane adhesive provided in the first aspect or the adhesive cured product provided in the third aspect of the present application in the preparation of packaging products.

[0050] In a fifth aspect, the present application provides a packaging product comprising one or more of the two-component polyurethane adhesive provided in the first aspect and the adhesive cured product provided in the third aspect of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the following briefly introduces the drawings required for use in the embodiments or the conventional technology descriptions. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the disclosed drawings without any creative work.

[0052] Figure 1 The A1 component in Example 1 of the present application 1 H-NMR spectrum.

[0053] Figure 2 For the B1 component in Example 1 of the present application 1 H-NMR spectrum.

[0054] Figure 3 The mixed glue obtained by mixing the glue in Example 1 of this application 1 H-NMR spectrum.

[0055] Figure 4 The A4 component in Example 4 of the present application 1 H-NMR spectrum.

[0056] Figure 5 The mixed glue obtained by mixing the glue in Example 4 of this application 1 H-NMR spectrum.

[0057] Figure 6 The B4 component in the comparative example 2 of this application 1 H-NMR spectrum.

[0058] Figure 7 The mixed glue obtained by mixing the glue in Comparative Example 2 of this application 1 H-NMR spectrum. DETAILED DESCRIPTION

[0059] To facilitate understanding of the present invention, the present invention will be described more fully below, along with preferred embodiments thereof. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. It should be understood that these embodiments are provided for the purpose of providing a more thorough and comprehensive understanding of the disclosure of the present invention.

[0060] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0061] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0062] The "range" disclosed in this application can be defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of a particular range. The range defined in this way can be inclusive or exclusive of end values, and any end value can be independently included or excluded, and can be arbitrarily combined, i.e., any lower limit can be combined with any upper limit to form a range. For example, if a range of 60 to 120 and 80 to 110 is listed for a particular parameter, it is understood that a range of 60 to 110 and 80 to 120 is also contemplated. In addition, if the minimum range values ​​listed are 1 and 2, and if the maximum range values ​​3, 4, and 5 are also listed, the following ranges can all be contemplated: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5. In this application, unless otherwise specified, the numerical range "a to b" represents an abbreviation of any real number combination between a and b, wherein a and b are both real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is simply an abbreviation for these numerical combinations. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to listing the parameter as, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and so on. For example, when a parameter is expressed as an integer selected from "2-10", this is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0063] In this application, "a plurality of" or "a plurality of" refers to a number greater than or equal to 2 unless otherwise specified. For example, "one or more" means one or more than or equal to two.

[0064] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0065] References to "embodiments" herein mean that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment or implementation of the present application. The appearance of such phrases in various locations in the specification does not necessarily refer to the same embodiment, nor does it necessarily refer to independent or alternative embodiments that are mutually exclusive with other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments. References to "implementations" herein have a similar understanding.

[0066] Those skilled in the art can understand that the order of writing each step in the method of each embodiment or example does not mean a strict execution order and does not constitute any limitation on the implementation process. The detailed execution order of each step should be determined by its function and possible internal logic. If not specifically stated, all steps of the present application can be performed in sequence or randomly, and preferably in sequence. For example, the method comprises steps (a) and (b), which means that the method can comprise steps (a) and (b) in sequence, or steps (b) and (a) in sequence. For example, the method also comprises step (c), which means that step (c) can be added to the method in any order, for example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0067] In the present application, the open technical features or technical solutions described by the words "containing", "including", "comprising" and the like do not exclude additional members other than the listed members, and can be regarded as providing both a closed feature or solution composed of the listed members and an open feature or solution including additional members in addition to the listed members. For example, A includes a1, a2 and a3, and unless otherwise specified, it can also include other members or can not include additional members, and can be regarded as providing both the feature or solution that "A is composed of a1, a2 and a3" and the feature or solution that "A includes a1, a2 and a3, and also includes other members". In the present application, unless otherwise specified, A (such as B) means that B is a non-limiting example of A, and it can be understood that A is not limited to B.

[0068] In the present application, "optionally", "optional" and "optional" mean that it can or can not be present, that is, it can be selected from either of the two parallel solutions "yes" or "no". If there are multiple "options" in a technical solution, unless otherwise specified, and there is no contradiction or mutual restriction, each "option" is independent.

[0069] Through systematic research on the reasons for the bonding failure of the solvent-free polyurethane adhesive under high temperature and stress, it is found that the 1 The proportion of the integral area in the range of 6.5ppm~10.0ppm in the H-NMR spectrum accounts for 1 The proportion of the total integral area has a great influence on the bonding property of the adhesive under high temperature and stress. The traditional solvent-free polyurethane adhesive does not consider controlling this proportion. By controlling the aromatic substances and aldehyde group-containing substances contained in the AB two components of the solvent-free polyurethane adhesive, the 1The ratio of the integral area in the region of 6.5ppm~10.0ppm in the H-NMR spectrum to the total integral area of the solvent-free polyurethane adhesive is 4%~30%. 1 The ratio of the total integral area in the H-NMR spectrum is 4%~30%.

[0070] Based on this, one embodiment of the present application provides a two-component polyurethane adhesive, comprising a component A and a component B.

[0071] The component A is a modified isocyanate, the end group of the modified isocyanate is isocyanate group, the component B is a polyhydroxy compound, and the component A and the component B are mixed according to the molar ratio R of the -NCO group in the component A to the -OH group in the component B, which is (1.5~2.2):1, and the obtained adhesive after mixing satisfies the following conditions: the obtained adhesive has a molecular weight distribution index of 1.5~2.5. 1 The ratio of the integral area in the region of 6.5ppm~10.0ppm in the H-NMR spectrum to the total integral area of the solvent-free polyurethane adhesive is 4%~30%.

[0072] In the above two-component polyurethane adhesive, the component A and the component B are mixed according to a specific molar ratio, and the obtained adhesive has a molecular weight distribution index of 1.5~2.5. 1 The ratio of the integral area in the region of 6.5ppm~10.0ppm in the H-NMR spectrum to the total integral area of the solvent-free polyurethane adhesive is 4%~30%. 1 By controlling the ratio of the total integral area in the H-NMR spectrum to be within the above specific range, the adhesive not only has higher intermolecular forces at high temperatures, but also has good cohesive force at high temperatures, and is endowed with good peel strength and interfacial adhesion, thereby improving the bonding performance of the polyurethane adhesive.

[0073] It is speculated that the reason is that the adhesive has 1 The region of 6.5ppm~10.0ppm in the H-NMR spectrum is the region with H in the conjugated group, and these conjugated groups include but are not limited to one or more of aryl groups and aldehyde groups with 6~20 carbon atoms, which can effectively improve the intermolecular interaction force and have a higher crystallization temperature than alkane substances, and can provide higher intermolecular forces and good cohesive force at high temperatures, and reasonable control of the proportion of the region of 6.5ppm~10.0ppm, i.e. reasonable control of the content of these conjugated groups, can take into account good cohesive force and interfacial adhesion, thereby improving the bonding performance of the polyurethane adhesive.

[0074] An aryl group having 6 to 20 carbon atoms refers to an aromatic hydrocarbon group having 6 to 20 carbon atoms, including a monocyclic aryl group and a condensed ring aryl group. A condensed ring aryl group refers to a group formed by connecting two or more monoaromatic rings through two shared adjacent ring atoms, i.e., a condensed ring. Furthermore, the number of ring carbon atoms in an aryl group having 6 to 20 carbon atoms is 6 to 20. In this application, the number of "ring atoms" represents the number of atoms bonded to form a ring. When the ring is substituted by a substituent, the atoms contained in the substituent are not included in the ring atoms. Regarding the "ring atoms" described below, the same applies unless otherwise specified. For example, the number of ring atoms of a benzene ring is 6, the number of ring atoms of a naphthalene ring is 10, and the number of ring atoms of a thiophene ring is 5. Non-limiting examples of the present application's "aryl" include: benzene, naphthalene, anthracene, fluoranthene, phenanthrene, triphenylene, perylene, tetracene, or fluorene.

[0075] In addition, the two-component polyurethane adhesive also has good bonding properties under mechanical pulling or stress.

[0076] Adhesive 1 The ratio of the integrated area of ​​the 6.5ppm~10.0ppm region in the H-NMR spectrum to the total integrated area refers to the test of the adhesive obtained by mixing components A and B according to a specific molar ratio before curing. 1 The proportion of the integral area of ​​the 6.5 ppm to 10.0 ppm region in the H-NMR spectrum to the total integral area can be 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, or any value within the range consisting of any two of the above point values ​​as end values, and can be selected from 8% to 30%.

[0077] In some embodiments, the adhesive obtained after the preparation of the glue 1 The integrated area of ​​the 6.5ppm to 10.0ppm region in the H-NMR spectrum accounts for 13% to 26% of the total integrated area. Further controlling this ratio within this range can improve the peel strength and interfacial adhesion of the polyurethane adhesive, while maintaining good cohesion at high temperatures, thereby enhancing the adhesive performance of the polyurethane adhesive.

[0078] In some embodiments, the A component 1 The integral area of ​​6.5ppm~10.0ppm in the H-NMR spectrum accounts for 6%~40% of the total integral area. 1The integrated area of ​​the 6.5ppm-10.0ppm region in the H-NMR spectrum accounts for 0.3%-25% of the total integrated area. By controlling the ratio of the 6.5ppm-10.0ppm region in each of component A and component B of a two-component polyurethane adhesive, the adhesive can have stronger intermolecular forces at high temperatures, thereby achieving good cohesion at high temperatures. It also imparts good peel strength and improves interfacial adhesion, thereby enhancing the adhesive performance of the polyurethane adhesive.

[0079] In addition, by controlling the ratio of component A to component B in the range of 6.5ppm to 10.0ppm, the adhesive obtained by mixing component A and component B in a specific molar ratio can be 1 The integrated area of ​​the 6.5ppm~10.0ppm region in the H-NMR spectrum accounts for 1 The ratio of the total integrated area in the H-NMR spectrum is controlled within the above-specified range.

[0080] A component 1 The ratio of the integral area of ​​6.5ppm~10.0ppm in the H-NMR spectrum to the total integral area refers to the test of component A as the test object, and the total integral area refers to the 1 The integrated area of ​​the H-NMR spectrum is the entire region. As an example, the A component 1 In the H-NMR spectrum, the proportion of the integrated area of ​​the 6.5 ppm to 10.0 ppm region to the total integrated area can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, or 40%, or any value within the range consisting of any two of the above point values ​​as end points.

[0081] B component 1 The ratio of the integral area of ​​6.5ppm~10.0ppm in the H-NMR spectrum to the total integral area refers to the B component tested as the test object, and the total integral area refers to the B component. 1 The integrated area of ​​the H-NMR spectrum is the entire region. As an example, the B component 1The proportion of the integrated area of ​​the 6.5 ppm to 10.0 ppm region in the H-NMR spectrum to the total integrated area can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, or any value within the range consisting of any two of the above point values ​​as end values.

[0082] One embodiment of the present application further provides a two-component polyurethane adhesive, comprising component A and component B;

[0083] Component A is a modified isocyanate, the terminal group of the modified isocyanate is an isocyanate group, component B is a polyhydroxy compound, and component A is 1 The integral area of ​​6.5ppm~10.0ppm in the H-NMR spectrum accounts for 6%~40% of the total integral area. 1 The integrated area of ​​the 6.5 ppm to 10.0 ppm region in the H-NMR spectrum accounts for 0.3% to 25% of the total integrated area.

[0084] The above-mentioned two-component polyurethane adhesive, by controlling the ratio of the 6.5ppm~10.0ppm region of the A component and the B component of the two-component polyurethane adhesive, can make the adhesive have a higher intermolecular force at high temperature, thereby being able to have good cohesion at high temperature, and also giving it good peel strength to improve the interfacial adhesion, thereby improving the bonding performance of the polyurethane adhesive.

[0085] In addition, by controlling the ratio of 6.5ppm~10.0ppm of each component A and component B, the molar ratio R of -NCO group in component A and -OH group in component B can be set to (1.5~2.2):1 after the adhesive is prepared. 1 The integrated area of ​​the 6.5ppm~10.0ppm region in the H-NMR spectrum accounts for 1 The ratio of the total integrated area in the H-NMR spectrum is controlled within the above-specified range.

[0086] A component 1 The ratio of the integral area of ​​6.5ppm~10.0ppm in the H-NMR spectrum to the total integral area refers to the test of component A as the test object, and the total integral area refers to the 1 The integrated area of ​​the H-NMR spectrum is the entire region. As an example, the A component 1The ratio of the integral area of ​​the 6.5ppm to 10.0ppm region in the H-NMR spectrum to the total integral area may be 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, or any value within the range formed by any two of the above point values ​​as end values. In some embodiments, the A component 1 The integrated area of ​​the 6.5 ppm to 10.0 ppm region in the H-NMR spectrum accounts for 15% to 40% of the total integrated area.

[0087] B component 1 The ratio of the integral area of ​​6.5ppm~10.0ppm in the H-NMR spectrum to the total integral area refers to the B component tested as the test object, and the total integral area refers to the B component. 1 The integrated area of ​​the H-NMR spectrum is the entire region. As an example, the B component 1 The ratio of the integral area of ​​the 6.5ppm to 10.0ppm region in the H-NMR spectrum to the total integral area may be 0.3%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, or any value within the range formed by any two of the above-mentioned points as end values. In some embodiments, the amount of component B is 0. 1 The integrated area of ​​the 6.5 ppm to 10.0 ppm region in the H-NMR spectrum accounts for 11% to 25% of the total integrated area.

[0088] In some embodiments, the ratio of component A to component B is based on a molar ratio R of -NCO groups in component A to -OH groups in component B of (1.5-2.2):1. By controlling the ratio of components A and B in the 6.5 ppm to 10.0 ppm range of the two-component polyurethane adhesive, further controlling the ratio of components A and B can enhance the intermolecular forces of the adhesive at high temperatures, thereby achieving better cohesion at high temperatures. Furthermore, the adhesive can be given better peel strength and enhanced interfacial adhesion, further improving the adhesive properties of the polyurethane adhesive.

[0089] As an example, the ratio of component A to component B, based on the molar ratio R of -NCO groups in component A to -OH groups in component B, can be 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, or any value within a range consisting of any two of the aforementioned values. Furthermore, R is (1.7-1.9):1.

[0090] The two-component polyurethane adhesive provided in this application is a solvent-free two-component polyurethane adhesive, which does not use any solvent during the preparation process.

[0091] In some embodiments, the NCO mass content of component A is 14% to 23%; as an example, it can be 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, or any value within the range formed by any two of the above point values ​​as end values.

[0092] In some embodiments, the hydroxyl value of component B is 170 gKOH / g~310 mgKOH / g; as an example, it can be 170 mgKOH / g, 180 mgKOH / g, 190 mgKOH / g, 200 mgKOH / g, 210 mgKOH / g, 220 mgKOH / g, 230 mgKOH / g, 240 mgKOH / g, 250 mgKOH / g, 260 mgKOH / g, 270 mgKOH / g, 280 mgKOH / g, 290 mgKOH / g, 300 mgKOH / g, 310 mgKOH / g, or any value within the range formed by any two of the above point values ​​as end values.

[0093] In some embodiments, component A includes one or more of a polyisocyanate copolymer, a polyisocyanate biuret, and a polyol-modified isocyanate, one or more of which contains a conjugated group, wherein the conjugated group includes one or more of an aromatic group having 6 to 20 carbon atoms and an aldehyde group. Optionally, component A contains a polyol-modified isocyanate.

[0094] Furthermore, in component A, the polyisocyanate copolymer is selected from one or more of an aromatic polyisocyanate copolymer, an aliphatic polyisocyanate copolymer and an alicyclic polyisocyanate copolymer.

[0095] Furthermore, in component A, the polyisocyanate biuret is selected from one or more of aromatic polyisocyanate biuret, aliphatic polyisocyanate biuret, and alicyclic polyisocyanate biuret.

[0096] Furthermore, in component A, the polyol in the polyol-modified isocyanate is selected from one or more of polyether polyols, polyester polyols, small molecule polyols, polycaprolactone polyols, polycarbonate polyols, polyetherester polyols, bio-based polyols, epoxy resins, and acrylate polyols, wherein the small molecule polyol is a C2-C10 polyol. It is understood that the polyol refers to a polyol containing two or more hydroxyl groups.

[0097] Furthermore, the number average molecular weight of the small molecule polyol in the polyol-modified isocyanate is 80-2000, and can be optionally 100-2000.

[0098] Furthermore, the small molecule polyol in the polyol-modified isocyanate is selected from one or more of diethylene glycol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propylene glycol, 1,4-butanediol, 1,6-hexanediol, terephthalic acid methanol, neopentyl glycol, 1,3-butanediol, 2-ethyl-1,3-hexanediol, 1,2-octanediol, glycerol and trimethylolpropane.

[0099] Furthermore, the polycaprolactone polyol in the polyol-modified isocyanate is a polyol obtained by ring-opening polymerization of caprolactone.

[0100] Furthermore, the polycarbonate polyol in the polyol-modified isocyanate is a polyol containing a carbonate group.

[0101] Furthermore, the polyetherester polyol in the polyol-modified isocyanate is a polyol containing a polyether segment and an ester bond.

[0102] Furthermore, the bio-based polyol in the polyol-modified isocyanate is selected from one or more of castor oil, soybean oil, palm oil, rosin ester and derivatives thereof.

[0103] Furthermore, the epoxy resin in the polyol-modified isocyanate is one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, novolac epoxy resin, hydrogenated bisphenol A epoxy resin, hydrogenated bisphenol F epoxy resin, alicyclic epoxy resin, o-cresol type epoxy resin, hydantoin epoxy resin, bisphenol S epoxy resin, bisphenol fluorene epoxy resin, polyurethane modified epoxy resin, rubber modified epoxy resin, and core-shell particle modified epoxy resin.

[0104] Furthermore, the acrylate polyol in the polyol-modified isocyanate is prepared by polymerization of acrylate monomers, and the acrylate monomers include one or more of monofunctional acrylate monomers, difunctional acrylate monomers and trifunctional acrylate monomers.

[0105] In some embodiments, the polyol-modified isocyanate is prepared by reacting a polyol with a polyisocyanate-based compound. The polyisocyanate-based compound is selected from one or more of aromatic polyisocyanates, aliphatic polyisocyanates, and alicyclic polyisocyanates. Furthermore, the types of the polyols are as described above and are not further described here.

[0106] Furthermore, the polyisocyanate-based raw material for preparing the polyol-modified isocyanate is selected from one or more of toluene diisocyanate, diphenylmethane diisocyanate (MDI), liquefied MDI, naphthalene diisocyanate, p-phenylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, xylylene diisocyanate, cyclohexane dimethylene diisocyanate, hexamethylene diisocyanate, homopolymers of the aforementioned isocyanate monomers, and biuret of the aforementioned isocyanate monomers. Liquefied MDI is a liquefied modified product of diphenylmethane diisocyanate (MDI).

[0107] In some embodiments, component B includes one or more of small molecule polyols, polyether polyols, polyester polyols, polycaprolactone polyols, polyether ester polyols, polycarbonate polyols, bio-based polyols, epoxy resins, acrylate polyols and isocyanate-extended polyols, and one or more of them contains conjugated groups, the conjugated groups include one or more of aromatic groups and aldehyde groups with 6 to 20 carbon atoms, and the small molecule polyol is a C2-C10 polyol.

[0108] Furthermore, in component B, the number average molecular weight of the small molecule polyol is 80-2000, and can be optionally 100-2000.

[0109] Furthermore, in component B, the small molecule polyol is selected from one or more of diethylene glycol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propylene glycol, 1,4-butanediol, 1,6-hexanediol, terephthalic acid methanol, neopentyl glycol, 1,3-butanediol, 2-ethyl-1,3-hexanediol, 1,2-octanediol, glycerol and trimethylolpropane; and / or,

[0110] Furthermore, in component B, the polyether polyol is selected from one or more hydroxyl-terminated oligomers of polypropylene oxide, propylene oxide ethylene oxide copolymer and polytetrahydrofuran.

[0111] Furthermore, in component B, the number average molecular weight of the polyether polyol is 400 to 2000. Furthermore, the number average molecular weight of the hydroxyl-terminated oligomer of polytetrahydrofuran is 400 to 2000.

[0112] Further, in the B component, the polyester polyol is a hydroxyl-terminated oligomer obtained by high molecular condensation polymerization of a diacid and a polyol, the diacid is selected from one or more of adipic acid, isophthalic acid, terephthalic acid, phthalic anhydride and sebacic acid, and the polyol is selected from one or more of diethylene glycol, triethylene glycol, 1,2-propanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,3-butanediol, 2-ethyl-1,3-hexanediol, 1,2-octanediol, 1,8-octanediol, 2,5-dimethyl-2,5-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 3,6-octanediol, 2,2,4-trimethyl-1,3-pentanediol, glycerol and trimethylolpropane.

[0113] Further, in the B component, the number average molecular weight of the polyester polyol is 400-1000.

[0114] Further, in the B component, the polycaprolactone polyol is a polyol obtained by ring-opening polymerization of caprolactone.

[0115] Further, in the B component, the polycarbonate polyol is a polyol containing a carbonate group.

[0116] Further, in the B component, the polyether ester polyol is a polyol containing a polyether segment and an ester bond.

[0117] Further, in the B component, the bio-based polyol is selected from one or more of castor oil, soybean oil, palm oil, rosin esters and derivatives thereof.

[0118] Further, in the B component, the epoxy resin is selected from one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, phenolic epoxy resin, hydrogenated bisphenol A epoxy resin, hydrogenated bisphenol F epoxy resin, alicyclic epoxy resin, ortho-cresol type epoxy resin, hydantoin epoxy resin, bisphenol S epoxy resin, bisphenol fluorenyl epoxy resin, polyurethane-modified epoxy resin, rubber-modified epoxy resin and core-shell particle-modified epoxy resin.

[0119] Further, in the B component, the acrylate polyol is polymerized from acrylate monomers, the acrylate monomers include one or more of monofunctional acrylate monomers, difunctional acrylate monomers and trifunctional acrylate monomers.

[0120] Further, in the B component, the isocyanate in the isocyanate-extended polyol is selected from one or more of toluene diisocyanate, diphenylmethane diisocyanate, liquefied MDI, naphthalene diisocyanate, p-phenylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, xylylene diisocyanate, cyclohexane dimethylene diisocyanate, hexamethylene diisocyanate and homopolymers of the aforementioned isocyanate monomers.

[0121] Furthermore, the polyol in the isocyanate-extended polyol is one or more of a small molecule polyol, a polyester polyol, a polyether polyol, and a polycaprolactone polyol. It is understood that the types of small molecule polyols, polyester polyols, polyether polyols, and polycaprolactone polyols in the isocyanate-extended polyol are selected from the same range as the types of the respective polyols in the above-mentioned component B. Alternatively, the polyol in the isocyanate-extended polyol is one or more of a polyester polyol and a polyether polyol.

[0122] In a second aspect of the present application, a method for preparing the above-mentioned two-component polyurethane adhesive is provided, comprising the following steps:

[0123] Prepare component A and component B of the two-component polyurethane adhesive provided in the first aspect.

[0124] In the process of preparing component A and component B, the raw material composition of the raw materials can be adjusted and the intermediate products obtained in the reaction process can be tested during the preparation process. 1 H-NMR spectrum, and then, as needed, remove the raw materials containing the above-mentioned conjugated groups such as aromatic substances and / or aldehydes by vacuuming, or add raw materials containing the above-mentioned conjugated groups such as aromatic substances and / or aldehydes as needed, or add raw materials containing no aromatic substances and / or aldehydes as needed, so as to adjust the final A component. 1 The integral area of ​​6.5ppm~10.0ppm in the H-NMR spectrum accounts for 6%~40% of the total integral area. 1 The integrated area of ​​the 6.5 ppm to 10.0 ppm region in the H-NMR spectrum accounts for 0.3% to 25% of the total integrated area.

[0125] It is understandable that the characteristics such as the type selection of the AB component have been explained in detail above and will not be repeated here.

[0126] In some embodiments, the A component includes a polyol-modified isocyanate.

[0127] Furthermore, the polyol in the polyol-modified isocyanate is selected from one or more of polyether polyols and polyester polyols. Furthermore, the isocyanate in the polyol-modified isocyanate contains a conjugated group, wherein the conjugated group includes one or more of an aromatic group having 6 to 20 carbon atoms and an aldehyde group. In some examples, the isocyanate in the polyol-modified isocyanate includes an aromatic isocyanate, including but not limited to one or more of 2,4-toluene diisocyanate and diphenylmethane diisocyanate. Optionally, the isocyanate in the polyol-modified isocyanate also includes one or more of isophorone diisocyanate and hexamethylene diisocyanate-based polyisocyanate.

[0128] During the preparation of component A, if the above integral area ratio obtained by testing is less than 5%, the above integral area ratio may be increased by adding aromatic isocyanates and / or aromatic polyols to bring the value within the range. During the preparation of component A, if the above integral area ratio obtained by testing exceeds 40%, the aromatic substances and / or aldehyde substances may be removed by vacuuming to reduce the integral area ratio to bring the value within the range. Alternatively, an aliphatic isocyanate substance may be added to component A to reduce the integral area ratio to bring the value within the range. Alternatively, an aliphatic polyol substance may be added to component A to reduce the integral area ratio to bring the value within the range.

[0129] In some embodiments, component B includes one or more of a polyester polyol and an isocyanate-extended polyester polyol, wherein one or more of the polyester polyol and the isocyanate-extended polyester polyol contains a conjugated group, wherein the conjugated group includes one or more of an aromatic group having 6 to 20 carbon atoms and an aldehyde group. Furthermore, the polyester polyol contains the aforementioned conjugated groups; further, the isocyanate segments and / or polyester polyol structural units in the isocyanate-extended polyester polyol contain the aforementioned conjugated groups. In some examples, the isocyanate-extended polyester polyol includes an aromatic isocyanate, including but not limited to one or more of 2,4-toluene diisocyanate and diphenylmethane diisocyanate. Optionally, the isocyanate in the polyol-modified isocyanate further includes one or more of isophorone diisocyanate and hexamethylene diisocyanate-based polyisocyanate.

[0130] Furthermore, based on the above, component B further comprises one or more of a small molecule polyol and an isocyanate-extended small molecule polyol; further, component B further comprises one or more of a polyether polyol and an isocyanate-extended polyether polyol. Furthermore, the isocyanate-extended small molecule polyol and the isocyanate-extended polyether polyol contain the above-mentioned conjugated group.

[0131] During the preparation of component B, if the above integral area ratio obtained by testing is lower than 2%, aromatic isocyanate and / or aromatic polyol may be added to increase the above integral area ratio so that the value is within the range.

[0132] During the preparation of component B, if the above-mentioned integral area ratio obtained from the test is higher than 30%, the aromatic substances and / or aldehyde substances can be removed by vacuuming to reduce the integral area ratio so that the value is within the range; an aliphatic isocyanate substance can also be added to component B to reduce the integral area ratio so that the value is within the range; an aliphatic polyol substance can also be added to component B to reduce the integral area ratio so that the value is within the range.

[0133] Different raw materials 1 The proportion of the integrated area of ​​the 6.5ppm~10.0ppm region in the H-NMR spectrum to the total integrated area varies. Different raw materials can be combined as needed. For example, the ratio of toluene diisocyanate, diphenylmethane diisocyanate and xylylene diisocyanate is 1 The integral area of ​​the 6.5ppm~10.0ppm region in the H-NMR spectrum accounts for approximately 50%, 80% and 66.7% of the total integral area. 1 The integral area of ​​the 6.5ppm~10.0ppm region in the H-NMR spectrum accounts for 0% of the total integral area. 1 The integral area of ​​the 6.5ppm~10.0ppm region in the H-NMR spectrum can be selected according to different 1 The integrated area of ​​the 6.5 ppm to 10.0 ppm region in the H-NMR spectrum of epoxy resin.

[0134] Another embodiment of the present application provides a cured adhesive, which is obtained by curing the two-component polyurethane adhesive provided in the first aspect.

[0135] Another embodiment of the present application provides the use of the above-mentioned two-component polyurethane adhesive or the above-mentioned adhesive cured product in the preparation of packaging products.

[0136] Another embodiment of the present application provides a packaging product comprising one or more of the above-mentioned two-component polyurethane adhesive and the above-mentioned adhesive cured product.

[0137] In some embodiments, the packaging product includes a packaging body and an adhesive portion, wherein the adhesive portion includes one or more of the above-mentioned two-component polyurethane adhesive and the above-mentioned adhesive cured product. Furthermore, the packaging body is a flexible package.

[0138] The processing technology of some packaging products may use hot filling with gradual heating. Therefore, the above-mentioned adhesive in this application has good adhesion under high temperature and mechanical pulling, and is particularly suitable for such packaging products, including but not limited to packaging food products.

[0139] Furthermore, the packaging body of the packaged product may also contain contents.

[0140] In order to make the purpose, technical solutions and advantages of the present invention more concise and clear, the present invention is illustrated by the following specific embodiments, but the present invention is by no means limited to these embodiments. The embodiments described below are only preferred embodiments of the present invention and can be used to describe the present invention. They should not be understood as limiting the scope of the present invention. It should be pointed out that any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0141] In order to better illustrate the present invention, the present invention is further described below with reference to the following embodiments.

[0142] 1. The raw materials used are as follows:

[0143] Polyether polyols:

[0144] Polyether polyol 1: DL-400, polyoxypropylene glycol, molecular weight 400, produced by Shandong Bluestar Dongda Co., Ltd.; also known as polypropylene glycol 400 (PPG400);

[0145] Polyether polyol 2: DL-1000D, polyoxypropylene glycol, molecular weight 1000, produced by Shandong Bluestar Dongda Co., Ltd.; also known as polypropylene glycol 400 (PPG1000);

[0146] Polyether polyol 3: DMN400, polyoxypropylene triol, molecular weight 400, produced by Zibo Dexin Federal Corporation;

[0147] Polyether polyol 4: DMN1000, polyoxypropylene triol, molecular weight 1000, produced by Zibo Dexin Federal Corporation.

[0148] Small molecule polyols:

[0149] Small molecule alcohol 1: diethylene glycol (DEG), Aladdin;

[0150] Small molecule alcohol 2: 1,2-propylene glycol, Aladdin;

[0151] Small molecule alcohol 3: 1,4-butanediol, Aladdin;

[0152] Small molecule alcohol 4: p-phenylenediol, Aladdin;

[0153] Small molecule alcohol 5: 2-methyl-1,3-propanediol, Aladdin.

[0154] Dibasic acid:

[0155] Adipic acid, Aladdin;

[0156] Phthalic anhydride, Aladdin.

[0157] Aldehyde and ketone resin: CT-120, hydroxyl value 110 mg KOH / g, molecular weight 1150-1250, Jinan Changtai Chemical.

[0158] Polyester polyols:

[0159] Polyester polyol 1: Add 289g adipic acid, 210g diethylene glycol, 45g 1,2-propylene glycol, 53g 1,4-butanediol, and 403g CT-120 to a four-necked flask equipped with a condenser. Purge with nitrogen and heat to 100°C with stirring. Water will begin to flow when the temperature reaches 160°C. Control the temperature at the top of the fractionator between 100°C and 102°C. Continue heating the reaction flask until the temperature inside the flask reaches 240°C and maintain the temperature until the theoretical amount of water has been released. Continue to maintain the temperature for 2 hours after water release is complete. Increase the nitrogen flow and monitor the polyester hydroxyl value. When the polyester hydroxyl value reaches 175mgKOH / g, stop the nitrogen flow and begin cooling the temperature. Discharge the material when the temperature drops to 100°C.

[0160] Polyester polyol 2: Add 504g adipic acid, 366g diethylene glycol, 53g 1,2-propylene glycol, and 78g 1,4-butanediol to a four-necked flask equipped with a condenser. Purge with nitrogen and heat to 100°C with stirring. Water will begin to flow when the temperature reaches 160°C. Maintain the temperature at the top of the fractionator between 100°C and 102°C. Continue heating the reaction flask until the temperature inside the flask reaches 240°C and maintain the temperature until the theoretical water flow is complete. Continue maintaining the temperature for 2 hours after water flow is complete. Increase the nitrogen flow and monitor the polyester hydroxyl value. When the value reaches 175 mgKOH / g, stop nitrogen flow and begin cooling. Discharge the material when the temperature drops to 100°C.

[0161] Polyester polyol 3: Add 485g of phthalic anhydride, 382g of diethylene glycol, 75g of 1,2-propylene glycol, and 59g of 2-methyl-1,3-propanediol to a four-necked flask equipped with a condenser. Purge with nitrogen and heat to 100°C with stirring. Water will begin to flow when the temperature reaches 170°C. Maintain the temperature at the top of the fractionator between 100°C and 102°C. Continue heating the reaction flask until the temperature inside reaches 240°C and maintain the temperature until the theoretical water flow is complete. Continue maintaining the temperature for 2 hours after water flow is complete. Increase the nitrogen flow and monitor the polyester hydroxyl value. When the value reaches 220 mgKOH / g, stop nitrogen flow and begin cooling. Discharge the material when the temperature drops to 80°C.

[0162] Isocyanates:

[0163] Isocyanate 1: WANNATE TDI-100 (pure 2,4-toluene diisocyanate (TDI)), NCO% = 48.2 wt%, produced by Wanhua Chemical Group Co., Ltd.

[0164] Isocyanate 2: WANNATE MDI-50 (diphenylmethane diisocyanate (MDI) containing 50% 2,4'-diphenylmethane diisocyanate and 50% 4,4'-diphenylmethane diisocyanate isomer mixture), NCO% = 33.5wt%, produced by Wanhua Chemical Group Co., Ltd.;

[0165] Isocyanate 3: WANNATE IPDI (isophorone diisocyanate, which is an aliphatic diisocyanate), NCO% = 37.50wt%, produced by Wanhua Chemical Group Co., Ltd.;

[0166] Isocyanate 4: WANNATE HT-100 (hexamethylene diisocyanate-based polyisocyanate (HDI trimer), which is an aliphatic polyisocyanate), NCO% = 22wt%, mass fraction of HDI monomer ≤0.2%, produced by Wanhua Chemical Group Co., Ltd.

[0167] II. Test methods involved in the examples are as follows:

[0168] (1) Isocyanate monomer free content: tested using liquid chromatography equipment.

[0169] (2) Test method of NCO: tested according to GB / T 12009.4-2016 Plastics - Aromatic isocyanates for polyurethane production - Part 4: Determination of isocyanate content.

[0170] (3) Test method of hydroxyl value: tested according to GB / T 12008.3-2009 Plastics - Polyether polyols - Part 3: Determination of hydroxyl number.

[0171] (4) 1 H-NMR test: dissolve the sample in deuterated chloroform solvent, load into a test sample tube, and put into a nuclear magnetic resonance instrument for testing.

[0172] III. Preparation method is as follows:

[0173] (1) Preparation of component A:

[0174] According to the mass fraction ratio of raw materials shown in Table 1, the isocyanate raw materials are put into the reaction device, the polyol raw materials are added, the stirring is increased, and the temperature is increased to 80±5℃. After 2 hours of reaction, the temperature is decreased to 50℃, and the modified isocyanate component is obtained. Then, the modified isocyanate component is tested by H-NMR, and the integral area ratio of the 6.5ppm~10.0ppm region is obtained. 1 H-NMR, the integral area ratio of the 6.5ppm~10.0ppm region is obtained.

[0175] During the preparation of components A1 to A4, if the above-mentioned integrated area ratio obtained from the discharge test is within a range of 6% to 40%, the obtained modified isocyanate component is component A.

[0176] After confirming that the integrated area ratio of the modified isocyanate obtained from A5 was higher than 40%, part of the material was discharged to obtain A5.

[0177] The undischarged portion A5 was subjected to further post-processing: the aromatic isocyanate monomer was removed by vacuuming to reduce the integrated area ratio. The final product was numbered A6.

[0178] A7: Add the isocyanate raw materials (all except isocyanate HT-100) into the reaction device according to the mass ratio of the raw materials shown in Table 1, add the polyol raw materials, increase the stirring, raise the temperature to 80±5℃, react for 2 hours, cool to 50℃, and then discharge the modified isocyanate component. Then, test the modified isocyanate component. 1 After the H-NMR spectrum showed an integrated area ratio of greater than 40% in the 6.5-10.0 ppm region, 19.97 parts of aliphatic isocyanate HT100 was added to reduce this integrated area ratio. The final product was designated A7.

[0179] A8: Add the isocyanate raw material into the reaction device according to the mass ratio of the raw materials shown in Table 1, add the polyol raw material (all except polyester polyol 2), increase the stirring, raise the temperature to 80±5℃, react for 2 hours, cool to 50℃, and then discharge the modified isocyanate component. Then, test the modified isocyanate component. 1 After the H-NMR spectrum showed an integrated area ratio of greater than 40% in the 6.5-10.0 ppm region, 25.65 parts of aliphatic polyol polyester polyol 2 was added to reduce this integrated area ratio. The final product was designated A8.

[0180] Table 1

[0181]

[0182] (2) Preparation of component B:

[0183] According to the mass fraction of the raw materials shown in Table 2, polyester polyol, optional small molecule polyol, optional polyether polyol, and optional isocyanate raw materials are all put into the reaction device, heated to 80±5°C, reacted for 2 hours, and then the sample was sampled and tested. 1 The integrated area ratio of the 6.5 ppm to 10.0 ppm region was calculated by H-NMR.

[0184] During the preparation of components B1 to B3, if the above-mentioned integrated area ratio obtained from the discharge test is within 0.3% to 25%, the sampled product can be discharged as component B.

[0185] The above-mentioned integrated area obtained from the B4 discharge test accounts for more than 30%.

[0186] B5: According to the mass ratio of the raw materials shown in Table 2, polyester polyol and small molecule polyol raw materials are put into the reaction device, heated to 80±5℃, reacted for 2 hours, and then sampled and tested. 1 H-NMR was used to calculate the integrated area percentage in the region from 6.5 ppm to 10.0 ppm. After confirming that the integrated area percentage exceeded 30%, a portion of the aromatic polyol (polyester polyol) was removed by vacuum extraction to reduce the integrated area percentage, yielding B5.

[0187] B6: According to the mass ratio of the raw materials shown in Table 2, polyester polyol (polyester polyol 3, without polyester polyol 2) and small molecule polyol raw materials were put into the reaction device, heated to 80±5℃, reacted for 2 hours, and then samples were taken for testing. 1 H-NMR was used to calculate the integrated area percentage in the region from 6.5 ppm to 10.0 ppm. After confirming that the integrated area percentage exceeded 30%, an aliphatic polyol (20 parts of polyester polyol 2) was added to reduce the integrated area percentage, yielding B6.

[0188] B7: According to the mass ratio of the raw materials shown in Table 2, polyester polyol (polyester polyol 3) and small molecule polyol raw materials were put into the reaction device, heated to 80±5℃, and reacted for 2 hours. Then, samples were taken for testing. 1 H-NMR calculations were performed for the integrated area percentage in the 6.5 ppm to 10.0 ppm region. After confirming that the integrated area percentage exceeded 30%, an aliphatic isocyanate (20 parts IPDI) was added to reduce the integrated area percentage, yielding B7.

[0189] Table 2

[0190]

[0191] (3) Component A and component B are packaged and combined separately to obtain a two-component polyurethane adhesive.

[0192] (4) Application of two-component polyurethane adhesive. Component A and component B are mixed according to the molar ratio R of -NCO groups in component A to -OH groups in component B of (1.7-1.9):1 to obtain a mixed adhesive. The mixed adhesive is applied to one surface of the PET film. A PE film is then placed on the surface of the PET film coated with the mixed adhesive to bond the PET film and the PE film. The adhesive is cured in a 45°C curing chamber for 48 hours to obtain a PET / PE composite film.

[0193] PET / PE composite films were prepared in various examples and comparative examples. The component A and component B of the two-component polyurethane adhesive and their proportions were shown in Table 3.

[0194] 4. The performance test of two-component polyurethane adhesive is as follows:

[0195] (1) Peel strength test method: Cut the PET / PE composite film into strips with a width of 15 mm, and then use a peeling machine to test the strips in accordance with the standard GB / T 8808-1988.

[0196] (2) Hot filling test with 100°C hot water: The PET / PE composite film is made into bags, and 100°C hot water is filled into the bags. The bags are then heat-sealed and kept for 30 minutes. The parts in contact with the hot water are then observed to see if there is any stratification, and the film condition after hot filling is obtained.

[0197] (3) Two-component polyurethane adhesive 1 H-NMR test: Mix component A, component B or component AB in proportion to obtain a mixed glue, add it into deuterated chloroform and mix evenly. The sample is in liquid state. 1 H-NMR.

[0198] The A1 component in Example 1 of the present application 1 H-NMR graph, B1 component, mixed glue obtained by mixing 1 The H-NMR spectra are Figure 1 、 Figure 2 and Figure 3 As shown. In Example 4 of the present application, the A4 component and the prepared adhesive are mixed to obtain the mixed adhesive. 1 The H-NMR spectra are Figure 4 、 Figure 5 As shown. In comparative example 2 of this application, component B4 and the prepared adhesive are mixed to obtain a mixed adhesive. 1 The H-NMR spectra are Figure 6 、 Figure 7 shown.

[0199] The parameters and performance results of the PET / PE composite films prepared in various embodiments and comparative examples are shown in Table 3.

[0200] Table 3

[0201]

[0202] From the results in Table 3, it can be seen that the adhesives used in Examples 1 to 10 are used to bond PET film and PE film. The resulting PET / PE composite films have good peel strength and no delamination occurs in the films after hot filling.

[0203] The peel strength of the PET / PE composite films obtained in Comparative Examples 1 to 3 is lower than that of Examples 1 to 10 and does not meet the national standard requirement of 2.0 N / 15 mm. This is because the adhesive components A or B used in Comparative Examples 1 to 2 1 The integral area of ​​the 6.5ppm~10.0ppm region in the H-NMR spectrum accounts for too high a proportion of the total integral area, which makes the adhesive's own cohesive force too high, resulting in a negative impact on the adhesion. 1 The H-NMR spectrum shows that the integrated area of ​​the 6.5-10.0 ppm region is too low as a percentage of the total integrated area, resulting in weak cohesion within the adhesive, which negatively impacts adhesion. Furthermore, the films of Comparative Examples 1-3 exhibited delamination after hot filling, which is attributed to low peel strength.

[0204] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0205] The above-described embodiments merely represent several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art may make various modifications and improvements without departing from the spirit of the present invention, and these modifications and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be based on the appended claims, and the description may be used to interpret the content of the claims.

Claims

1. A two-component polyurethane adhesive, characterized in that: It includes component A and component B; The component A is a modified isocyanate, the terminal group of the modified isocyanate is an isocyanate group, the component B is a polyhydroxy compound, and the molar ratio R of the -NCO group in the component A to the -OH group in the component B is (1.5-2.2):

1. The adhesive obtained after the preparation meets the following conditions: 1 The integrated area of ​​the 6.5 ppm to 10.0 ppm region in the H-NMR spectrum accounts for 4% to 30% of the total integrated area.

2. The two-component polyurethane adhesive according to claim 1, characterized in that: The adhesive obtained after the preparation of the glue 1 The integrated area of ​​the 6.5 ppm to 10.0 ppm region in the H-NMR spectrum accounts for 13% to 26% of the total integrated area.

3. The two-component polyurethane adhesive according to claim 1, characterized in that: The A component 1 The integral area of ​​the 6.5ppm~10.0ppm region in the H-NMR spectrum accounts for 6%~40% of the total integral area. 1 The integrated area of ​​the 6.5 ppm to 10.0 ppm region in the H-NMR spectrum accounts for 0.3% to 25% of the total integrated area.

4. A two-component polyurethane adhesive, characterized in that: It includes component A and component B; The component A is a modified isocyanate, the terminal group of the modified isocyanate is an isocyanate group, the component B is a polyhydroxy compound, and the terminal group of the component A is an isocyanate group. 1 The integral area of ​​the 6.5ppm~10.0ppm region in the H-NMR spectrum accounts for 6%~40% of the total integral area. 1 The integrated area of ​​the 6.5 ppm to 10.0 ppm region in the H-NMR spectrum accounts for 0.3% to 25% of the total integrated area.

5. The two-component polyurethane adhesive according to any one of claims 1 to 4, characterized in that: The A component 1 The proportion of the integrated area of ​​the 6.5 ppm to 10.0 ppm region in the H-NMR spectrum to the total integrated area is 15% to 40%; and / or, The B component 1 The integrated area of ​​the 6.5 ppm to 10.0 ppm region in the H-NMR spectrum accounts for 11% to 25% of the total integrated area.

6. The two-component polyurethane adhesive according to any one of claims 1 to 4, characterized in that: The component A includes one or more of a polyisocyanate copolymer, a polyisocyanate biuret and a polyol-modified isocyanate, and one or more of them contains a conjugated group, and the conjugated group includes one or more of an aromatic group and an aldehyde group having 6 to 20 carbon atoms.

7. The two-component polyurethane adhesive according to claim 6, characterized in that: The polyisocyanate copolymer is selected from one or more of an aromatic polyisocyanate copolymer, an aliphatic polyisocyanate copolymer and an alicyclic polyisocyanate copolymer; and / or, The polyisocyanate biuret is selected from one or more of aromatic polyisocyanate biuret, aliphatic polyisocyanate biuret and alicyclic polyisocyanate biuret; and / or, The polyol in the polyol-modified isocyanate is selected from one or more of polyether polyols, polyester polyols, small molecule polyols, polycaprolactone polyols, polycarbonate polyols, polyether ester polyols, bio-based polyols, epoxy resins and acrylic polyols, wherein the small molecule polyol is a C2-C10 polyol.

8. The two-component polyurethane adhesive according to claim 7, characterized in that: The small molecule polyol is selected from one or more of diethylene glycol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propylene glycol, 1,4-butanediol, 1,6-hexanediol, terephthalic acid methanol, neopentyl glycol, 1,3-butanediol, 2-ethyl-1,3-hexanediol, 1,2-octanediol, glycerol and trimethylolpropane; and / or, The polycaprolactone polyol is a polyol obtained by ring-opening polymerization of caprolactone; and / or The polycarbonate polyol is a polyol containing carbonate groups; and / or, The polyetherester polyol is a polyol containing a polyether segment and an ester bond; and / or, The bio-based polyol is selected from one or more of castor oil, soybean oil, palm oil, rosin ester and derivatives thereof; and / or, The epoxy resin is one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, novolac epoxy resin, hydrogenated bisphenol A epoxy resin, hydrogenated bisphenol F epoxy resin, alicyclic epoxy resin, o-cresol epoxy resin, hydantoin epoxy resin, bisphenol S epoxy resin, bisphenol fluorene epoxy resin, polyurethane modified epoxy resin, rubber modified epoxy resin, and core-shell particle modified epoxy resin; and / or, The acrylic ester polyol is prepared by polymerizing acrylic ester monomers, wherein the acrylic ester monomers include one or more of monofunctional acrylic ester monomers, difunctional acrylic ester monomers and trifunctional acrylic ester monomers.

9. The two-component polyurethane adhesive according to claim 6, characterized in that: The polyol-modified isocyanate is formed by reacting a polyol with a polyisocyanate-based compound; The polyisocyanate compound is selected from one or more of aromatic polyisocyanates, aliphatic polyisocyanates and alicyclic polyisocyanates; Optionally, the polyisocyanate-based compound is selected from one or more of toluene diisocyanate, diphenylmethane diisocyanate, liquefied MDI, naphthalene diisocyanate, p-phenylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, xylene diisocyanate, cyclohexane dimethylene diisocyanate, hexamethylene diisocyanate, and homopolymers of the aforementioned isocyanate monomers and biuret of the aforementioned isocyanate monomers.

10. The two-component polyurethane adhesive according to any one of claims 1 to 4, characterized in that: The B component includes one or more of small molecule polyols, polyether polyols, polyester polyols, polycaprolactone polyols, polyether ester polyols, polycarbonate polyols, bio-based polyols, epoxy resins, acrylate polyols and isocyanate-extended polyols, and one or more of them contains conjugated groups, and the conjugated groups include one or more of aromatic groups and aldehyde groups with a carbon number of 6 to 20, and the small molecule polyol is a C2-C10 polyol.

11. The two-component polyurethane adhesive according to claim 10, characterized in that: In the B component, The small molecule polyol is selected from one or more of diethylene glycol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propylene glycol, 1,4-butanediol, 1,6-hexanediol, terephthalic acid methanol, neopentyl glycol, 1,3-butanediol, 2-ethyl-1,3-hexanediol, 1,2-octanediol, glycerol and trimethylolpropane; and / or, The polyether polyol is selected from one or more hydroxyl-terminated oligomers of polypropylene oxide, propylene oxide ethylene oxide copolymer and polytetrahydrofuran; and / or, The number average molecular weight of the polyether polyol is 400 to 2000; and / or, The polyester polyol is a hydroxyl-terminated oligomer obtained by a high molecular weight condensation polymerization reaction of a dibasic acid and a polyol, wherein the dibasic acid is selected from one or more of adipic acid, isophthalic acid, terephthalic acid, phthalic anhydride and sebacic acid, and the polyol is selected from one or more of diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,3-butanediol, 2-ethyl-1,3-hexanediol, 1,2-octanediol, 1,8-octanediol, 2,5-dimethyl-2,5-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 3,6-octanediol, 2,2,4-trimethyl-1,3-pentanediol, glycerol and trimethylolpropane; and / or, The number average molecular weight of the polyester polyol is 400 to 1000; and / or, The polycaprolactone polyol is a polyol obtained by ring-opening polymerization of caprolactone; and / or The polycarbonate polyol is a polyol containing carbonate groups; and / or, The polyetherester polyol is a polyol containing a polyether segment and an ester bond; and / or, The bio-based polyol is selected from one or more of castor oil, soybean oil, palm oil, rosin ester and derivatives thereof; The epoxy resin is selected from one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, novolac epoxy resin, hydrogenated bisphenol A epoxy resin, hydrogenated bisphenol F epoxy resin, alicyclic epoxy resin, o-cresol epoxy resin, hydantoin epoxy resin, bisphenol S epoxy resin, bisphenol fluorene epoxy resin, polyurethane modified epoxy resin, rubber modified epoxy resin and core-shell particle modified epoxy resin; and / or, The acrylic acid ester polyol is polymerized from acrylic acid ester monomers, wherein the acrylic acid ester monomers include one or more of monofunctional acrylic acid ester monomers, difunctional acrylic acid ester monomers and trifunctional acrylic acid ester monomers; and / or, The isocyanate in the isocyanate-extended polyol is selected from one or more of toluene diisocyanate, diphenylmethane diisocyanate, liquefied MDI, naphthalene diisocyanate, p-phenylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, xylylene diisocyanate, cyclohexane dimethylene diisocyanate, hexamethylene diisocyanate and homopolymers of the aforementioned isocyanate monomers; and / or, The polyol in the isocyanate-extended polyol is one or more of small molecule polyol, polyester polyol, polyether polyol and polycaprolactone polyol; optionally, the polyol in the isocyanate-extended polyol is one or more of polyester polyol and polyether polyol.

12. The two-component polyurethane adhesive according to any one of claims 1 to 4, characterized in that: The NCO mass content of the A component is 14% to 23%; and / or, The hydroxyl value of the B component is 170 gKOH / g to 310 mgKOH / g.

13. The two-component polyurethane adhesive according to claim 4, characterized in that: The usage ratio of the component A and the component B is based on the molar ratio R of the -NCO group in the component A to the -OH group in the component B being (1.5-2.2):

1.

14. A method for preparing a two-component polyurethane adhesive, characterized in that: The steps include: Prepare the component A and the component B in the two-component polyurethane adhesive according to any one of claims 4 to 13.

15. A cured adhesive, characterized in that: The adhesive is prepared by curing the two-component polyurethane adhesive as claimed in any one of claims 1 to 13.

16. Use of the two-component polyurethane adhesive according to any one of claims 1 to 13 or the cured adhesive according to claim 15 in the preparation of packaging products.

17. A packaging product, characterized in that: Contains one or more of the two-component polyurethane adhesive according to any one of claims 1 to 13 and the adhesive cured product according to claim 15.

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