Two-component solvent-free polyurethane adhesive, preparation method and polyurethane product

Abstract

The invention discloses a two-component solvent-free polyurethane adhesive, a preparation method and a polyurethane product, the polyurethane adhesive comprises a component A and a component B. The component A is modified isocyanate with isocyanate as a terminal group, and free isocyanate in the component A accounts for 0-1% of the total mass of a polyurethane prepolymer of the component A; the component B is a polyhydroxy compound and comprises one or more of polyether polyol, polyester polyol, polycaprolactone polyol and isocyanate chain extension polyol; and the concentration of the carbamate in the component A and the component B is 0.05-0.5 mol / 100g. According to the two-component solvent-free polyurethane adhesive disclosed by the invention, the polyurethane adhesive with good adhesive property can be prepared by controlling the concentration of the carbamate.

Description

Technical Field

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

[0002] In recent years, organic adhesives have been used more and more widely, and bonding technology has also matured. It can bond plastic / plastic, plastic / metal, metal / metal, stone / stone, etc., becoming one of the three major contemporary connection technologies, bonding, welding, and mechanical connection. From the perspective of industry, adhesives can be used in the soft packaging industry, fabric industry, furniture industry, battery industry, aviation industry, etc. Each industry has its own specific and special interfaces that need to be bonded. For example, in the soft packaging industry, common bonding interfaces include OPP / CPP, PET / PE, PA / RCPP, AL / RCPP, PET / paper, etc. There are relevant regulations for the peel strength of adhesives in each industry in each region. For example, my country's standards for soft packaging include "GB / T 10004-2008 Plastic composite film and bag dry composite, extrusion composite" and "GB / T 41168-2021 Plastic and aluminum foil steam composite film and bag for food packaging". In practical applications, flexible packaging films face many challenges. First, flexible packaging needs to be in contact with various contents, such as meat, milk, juice, laundry detergent, alcohol, etc. These contents will corrode the film and adhesive. Secondly, the mechanical stress caused by the weight of the flexible packaging itself. Even the bag type and sealing type of the flexible packaging will have a destructive effect on the overall or local peel strength. Other industries also have their own bonding problems that need to be solved. How to prepare an adhesive with good adhesion has always been the focus of attention in various industries.

[0003] Chinese patent application CN 102441955A discloses a two-component polyurethane adhesive, which consists of AB components, component A is 1 part of polyisocyanate and 2 parts of xylene; component B is 40 parts of xylene, 20 parts of ethyl acetate, 15 parts of ethylene glycol, 10 parts of chloroprene rubber, 5 parts of zinc chloride, 2643 parts of anti-aging agent, and 2 parts of barium stearate. The adhesive is used for bonding leather, rubber, fabric, linoleum, various foam plastics, and polyvinyl chloride. It has excellent mechanical properties such as bending resistance and impact resistance, good peel strength, acid and alkali resistance, solvent resistance, mildew resistance, etc., and still has high bonding strength at low temperatures. However, the adhesive has a low solid content and is not environmentally friendly.

[0004] Chinese patent application CN 104031595A discloses a polyurethane adhesive, a method for making the adhesive and a method for using the polyurethane adhesive. The adhesive is composed of two components, component A and component B. Component A is 65 parts of triphenylmethane triisocyanate and 4 parts of zinc chloride; component B is 110 parts of chloroprene rubber, 4 parts of calcium chloride, 3 parts of N-phenyl-2-naphthylamine, 90 parts of toluene, and 60 parts of ethyl acetate. The adhesive has excellent bonding properties and excellent mechanical properties such as bending resistance and impact resistance. It can be used for bonding leather, rubber, fiber, various foam plastics, ceramics, peeling, paper, fabric, polyvinyl chloride, metal (steel, aluminum, copper), etc. However, the adhesive also has a high solvent content, which is not conducive to environmental protection.

[0005] Chinese patent CN 101633828B application discloses a high temperature resistant water-based polyurethane adhesive and its preparation method. The adhesive is prepared by adding acetone to a polyol and then reacting with isocyanic acid to generate a prepolymer of terminal isocyanic acid, and a hydrophilic group is introduced into the reaction to extend the chain. Then a salt-forming agent is added to form a salt, water is added to emulsify it, and a special functional chain extender is added to extend the chain for the second time, and finally compounding is performed. The adhesive has a large initial adhesion, high bonding strength, and low activation temperature, and can be used for bonding PET, PE, and paper, fabrics, and non-woven fabrics. However, the mechanical properties of water-based polyurethane adhesives are poor, and they are not suitable for composite structures that need to have certain mechanical properties such as bending resistance and impact resistance. Therefore, the development of water-based polyurethane adhesives in the actual market is very slow.

[0006] What polyurethane adhesives need to solve is how to have good adhesion on various complex bonding interfaces and meet the certain mechanical properties required by composite structures. The adhesion of adhesives to interfaces is generally achieved through interaction forces, which include: van der Waals forces, ionic bonds, covalent bonds, chemical bonds, entanglement of molecular chains, static electricity, and mechanical forces. The strength of the adhesive itself is also maintained by the interaction forces between groups, segments, molecules, etc. When the intrinsic interaction force of the adhesive is strong, the mechanical properties of the adhesive itself are strong, including the tensile strength and fracture strength of the adhesive itself. However, the components of the interaction force that the adhesive itself can form are limited. If the intrinsic interaction force is strong, it will attract components (groups, segments, molecules, etc.) that can interact to form interaction forces in the adhesive body, thereby reducing the interaction forces with the interface, and ultimately resulting in poor bonding strength. Therefore, it is necessary to balance the intrinsic and extrinsic interaction forces to achieve a high enough strength while forming good adhesion. Summary of the invention

[0007] The purpose of the present invention is to provide a more environmentally friendly solvent-free two-component polyurethane adhesive that can have good adhesion in various interfaces and does not fail under a certain force, thereby ensuring the integrity of the structure in downstream applications. Specifically, a two-component solvent-free polyurethane adhesive and a preparation method and application are provided, which can effectively bond various interfaces by controlling the overall concentration of urethane.

[0008] In order to achieve the above-mentioned invention object, the present invention adopts the following technical scheme:

[0009] A two-component solvent-free polyurethane adhesive comprises a component A and a component B, wherein the component A is a modified isocyanate having an isocyanate terminal group, and the free isocyanate in the component A accounts for 0-1% of the total mass of the polyurethane prepolymer in the component A; the component B is a polyhydroxy compound, comprising one or more of small molecule alcohols, polyether polyols, polyester polyols, polycaprolactone polyols, polyether ester polyols, polycarbonate polyols, bio-based polyols, epoxy resins, acrylate polyols and isocyanate-extended polyols; and the concentration of carbamate in the two components A and B is 0.05-0.5 mol / 100g.

[0010] In a specific embodiment, the free isocyanate in the A component accounts for 0-0.5% of the total mass of the polyurethane prepolymer in the A component, preferably 0-0.1%.

[0011] In a specific embodiment, the modified isocyanate with an isocyanate terminal group in the A component is one or more of a polyisocyanate copolymer, a polyisocyanate biuret and a polyol-modified isocyanate.

[0012] In a specific embodiment, the polyisocyanate copolymer is selected from aromatic polyisocyanate copolymers, aliphatic polyisocyanate copolymers, and alicyclic polyisocyanate copolymers; the polyisocyanate biuret is selected from aromatic polyisocyanate biuret, aliphatic polyisocyanate biuret, and alicyclic polyisocyanate biuret; and the polyol-modified isocyanate is formed by the reaction of a polyhydroxy compound and a polyisocyanate-based compound.

[0013] In a specific embodiment, the polyisocyanate-based compound is selected from at least one of aromatic polyisocyanates, aliphatic polyisocyanates, and aliphatic cyclopolyisocyanates; preferably, the polyisocyanate-based compound is selected from 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, homopolymers of various isocyanate monomers, and one or more of the biuret of various isocyanate monomers.

[0014] In a specific embodiment, the polyol in the polyol-modified isocyanate is preferably one or more of polyether polyol, polyester polyol, small molecule polyol, polycaprolactone polyol, polycarbonate polyol, polyether ester polyol, bio-based polyol, epoxy resin and acrylate polyol.

[0015] In a specific embodiment, the small molecule polyol is selected from one or more polyols with a molecular weight of 100-2000 containing more than two hydroxyl groups; preferably, 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, neopentyl glycol, 1,3-butanediol, 2-ethyl-1,3-hexanediol, 1,2-octanediol, glycerol and trimethylolpropane.

[0016] In a specific embodiment, the polycaprolactone polyol is a polyol obtained by ring-opening polymerization of caprolactone.

[0017] In a specific embodiment, the polycarbonate polyol is a polyol containing carbonate groups.

[0018] In a specific embodiment, the polyetherester polyol is a polyol containing both a polyether segment and an ester bond (—CO—O—).

[0019] In a specific embodiment, the bio-based polyol consists of one or more of castor oil, soybean oil, palm oil, rosin esters and derivatives thereof.

[0020] In a specific embodiment, the epoxy resin is at least one 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.

[0021] In a specific embodiment, the acrylic ester polyol is polymerized from acrylic ester monomers, and the acrylic ester monomers include one or more of monofunctional acrylic ester monomers, difunctional acrylic ester monomers, and trifunctional acrylic ester monomers.

[0022] In a specific embodiment, the isocyanate in the isocyanate-extended polyol in component B 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 their respective isocyanate monomers; the polyol in the isocyanate-extended polyol in component B is at least any one of a small molecule alcohol with a functionality of more than two, a polyester polyol, a polyether polyol, and a polycaprolactone polyol, preferably a polyester polyol or a polyether polyol.

[0023] In a specific embodiment, in the isocyanate-extended polyol in the B component, the small molecule polyol is selected from one or more polyols having a molecular weight of 100-2000 and containing more than two hydroxyl groups; preferably, 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, neopentyl glycol, 1,3-butanediol, 2-ethyl-1,3-hexanediol, 1,2-octanediol, glycerol and trimethylolpropane.

[0024] In a specific embodiment, in the isocyanate-extended polyol in the B component, the polyether polyol is selected from at least any one of polypropylene oxide, propylene oxide ethylene oxide copolymer, and hydroxyl-terminated oligomers of polytetrahydrofuran, preferably a hydroxyl-terminated oligomer of polypropylene oxide, and more preferably a polyether polyol having a molecular weight of 400-2000.

[0025] In a specific embodiment, in the isocyanate-extended polyol in the B component, the polyester polyol is a hydroxyl-terminated oligomer obtained by a polymer condensation polymerization reaction of a dibasic acid and a polyol, the dibasic acid is preferably selected from one or more of adipic acid, isophthalic acid, terephthalic acid, phthalic anhydride, and sebacic acid, and the polyol is preferably 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; preferably, the molecular weight of the polyester polyol is 400-1000.

[0026] In a specific embodiment, in the isocyanate-chain-extended polyol in the B component, the polycaprolactone polyol is a polyol obtained by ring-opening polymerization of caprolactone.

[0027] In a specific embodiment, in the isocyanate-extended polyol in the B component, the polycarbonate polyol is a polyol containing a carbonate group (—O—CO—O—).

[0028] In a specific embodiment, in the isocyanate-extended polyol in the B component, the polyetherester polyol is a polyol containing both a polyether segment and an ester bond (—CO—O—).

[0029] In a specific embodiment, in the isocyanate-extended polyol in the B component, the bio-based polyol is composed of one or more of castor oil, soybean oil, palm oil, rosin ester and derivatives thereof.

[0030] In a specific embodiment, in the isocyanate-extended polyol in the B component, the epoxy resin is at least one 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.

[0031] In a specific embodiment, in the isocyanate-extended polyol in the B component, the acrylate polyol is polymerized from acrylate monomers, and the acrylate monomers include one or more of monofunctional acrylate monomers, difunctional acrylate monomers, and trifunctional acrylate monomers.

[0032] It will be understood by those skilled in the art that other additives, such as adhesion promoters, leveling agents, antibacterial agents, defoaming agents, etc., may be added to the two-component solvent-free polyurethane adhesive of the present invention according to process requirements, which is a routine operation in the art.

[0033] On the other hand, the preparation method of the aforementioned two-component solvent-free polyurethane adhesive is to mix the component A and the component B in proportion, wherein the free isocyanate in the component A accounts for 0-1% of the total mass of the polyurethane prepolymer in the component A; and the concentration of the urethane in the two components AB is adjusted to 0.05-0.5 mol / 100g to obtain the two-component solvent-free polyurethane adhesive.

[0034] In another aspect, a polyurethane product is prepared from the aforementioned two-component solvent-free polyurethane adhesive or a composition of the polyurethane adhesive prepared by the aforementioned preparation method.

[0035] The present invention achieves the following beneficial effects by adopting the above technical solution:

[0036] The two-component solvent-free polyurethane adhesive of the present invention can effectively bond a variety of interfaces by controlling the overall concentration of carbamate, because carbamate can form hydrogen bonds with the polar functional groups of the interface, forming effective bonding to both the polar interface and the non-polar interface after corona, and the carbamate within a specific content range can provide multiple interaction sites at the same time, which can effectively improve the bonding strength while improving its own cohesion, thereby effectively balancing the internal and external interaction forces, achieving a good bonding force while also having a high enough strength. In the preferred embodiment of the present invention, the low-free polyisocyanate compound can provide construction workers with a safer and more environmentally friendly use experience. DETAILED DESCRIPTION

[0037] In order to better understand the technical solution of the present invention, the following examples will further illustrate the method provided by the present invention, but the present invention is not limited to the listed examples, and should also include any other known changes within the scope of the claims of the present invention.

[0038] In one embodiment, a two-component solvent-free polyurethane adhesive comprises component A and component B, wherein component A is a modified isocyanate having an isocyanate terminal group; the free isocyanate of the polyurethane prepolymer of component A accounts for 0-1% of the total mass of the polyurethane prepolymer, for example, 0.01%, 0.02%, 0.05%, 0.06%, 0.08%, 0.1%, 0.125%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.7%, 0.8%, 0.9%, etc.; the component B is a polyol, including small molecule alcohol, polyether polyol, polyester polyol, polycaprolactone polyol, polyether ester polyol, polycarbonate polyol, bio-based polyol, epoxy resin, acrylate polyol and one or more of the polyols with isocyanate chain extension; and the concentration of carbamate in the two components AB is 0.05-0.5mol / 100g, for example, 0.06mol / 100g, 0.07mol / 100g, 0.08mol / 100g, 0.09mol / 100g, 0.1mol / 100g, 0.12mol / 100g, 0.15mol / 100g, 0.18mol / 100g, 0.2mol / 100g, 0.23mol / 100g, 0.25mol / 100g, 0.275mol / 100g, 0.3mol / 100g, 0.35mol / 100g, 0.4mol / 100g, 0.45mol / 100g, 0.5mol / 100g, etc., but not limited to this.

[0039] In a preferred embodiment, a two-component solvent-free polyurethane adhesive comprises component A and component B, wherein component A is a modified isocyanate having an isocyanate terminal group; component B is a polyol, comprising one or more of small molecule alcohols, polyether polyols, polyester polyols, polycaprolactone polyols, polyether ester polyols, polycarbonate polyols, bio-based polyols, epoxy resins, acrylate polyols and isocyanate-extended polyols; and the amino formaldehyde in the two components A and B is a polyol having a molecular weight of 1000 mmol / l. The concentration of the ester is 0.05-0.5 mol / 100g; the free isocyanate of the polyurethane prepolymer of component A accounts for 0-0.5% of the total mass of the polyurethane prepolymer, more preferably 0-0.1%, for example 0.01%, 0.02%, 0.05%, 0.06%, 0.08%, 0.1%, 0.125%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, preferably 0-0.1%.

[0040] The modified isocyanate with an isocyanate terminal group in component A is one or more of a polyisocyanate copolymer, a polyisocyanate biuret and a polyol-modified isocyanate. The polyisocyanate copolymer is selected from an aromatic polyisocyanate copolymer, an aliphatic polyisocyanate copolymer and an alicyclic polyisocyanate copolymer; the polyisocyanate biuret is selected from an aromatic polyisocyanate biuret, an aliphatic polyisocyanate biuret and an alicyclic polyisocyanate biuret; and the polyol-modified isocyanate is formed by the reaction of a polyhydroxy compound and a polyisocyanate compound.

[0041] The polyisocyanate-based compound is selected from at least one of aromatic polyisocyanates, aliphatic polyisocyanates, and aliphatic cyclopolyisocyanates; preferably, 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, homopolymers of various isocyanate monomers, and biuret of various isocyanate monomers.

[0042] The polyol (polyhydroxy compound) in the polyol-modified isocyanate is preferably one or more of polyether polyol, polyester polyol, small molecule polyol, polycaprolactone polyol, polycarbonate polyol, polyether ester polyol, bio-based polyol, epoxy resin and acrylate polyol.

[0043] Wherein, the small molecule polyol is selected from one or more polyols with a molecular weight of 100-2000 containing more than two hydroxyl groups; preferably, 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, neopentyl glycol, 1,3-butanediol, 2-ethyl-1,3-hexanediol, 1,2-octanediol, glycerol and trimethylolpropane.

[0044] The polycaprolactone polyol is a polyol obtained by ring-opening polymerization of caprolactone.

[0045] The polycarbonate polyol is a polyol containing carbonate groups.

[0046] The polyetherester polyol is a polyol containing both a polyether segment and an ester bond (-CO-O-).

[0047] The bio-based polyol is composed of one or more of castor oil, soybean oil, palm oil, rosin ester and derivatives thereof.

[0048] The epoxy resin is at least one 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.

[0049] The acrylic ester polyol is polymerized from acrylic ester monomers, and the acrylic ester monomers include one or more of monofunctional acrylic ester monomers, difunctional acrylic ester monomers and trifunctional acrylic ester monomers.

[0050] The B component is a polyhydroxy compound, including one or more of small molecule alcohols, polyether polyols, polyester polyols, polycaprolactone polyols, polyether ester polyols, polycarbonate polyols, bio-based polyols, epoxy resins, acrylic polyols and isocyanate-extended polyols.

[0051] Wherein, the small molecule polyol is selected from one or more polyols with a molecular weight of 100-2000 containing more than two hydroxyl groups; preferably, 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, neopentyl glycol, 1,3-butanediol, 2-ethyl-1,3-hexanediol, 1,2-octanediol, glycerol and trimethylolpropane.

[0052] The polyether polyol is at least one selected from polypropylene oxide, propylene oxide ethylene oxide copolymer, and hydroxyl-terminated oligomers of polytetrahydrofuran, preferably a hydroxyl-terminated oligomer of polypropylene oxide, and more preferably a polyether polyol with a molecular weight of 400-2000.

[0053] The polyester polyol is a hydroxyl-terminated oligomer obtained by a polymer condensation polymerization reaction of a dibasic acid and a polyol. The dibasic acid is preferably selected from one or more of adipic acid, isophthalic acid, terephthalic acid, phthalic anhydride, and sebacic acid. The polyol is preferably 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. Preferably, the molecular weight of the polyester polyol is 400-1000.

[0054] The polycaprolactone polyol is a polyol obtained by ring-opening polymerization of caprolactone.

[0055] The polycarbonate polyol is a polyol containing a carbonate group (—O—CO—O—).

[0056] The polyetherester polyol is a polyol containing both a polyether segment and an ester bond (-CO-O-).

[0057] The bio-based polyol is composed of one or more of castor oil, soybean oil, palm oil, rosin ester and derivatives thereof.

[0058] The epoxy resin is at least one 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.

[0059] The acrylic ester polyol is polymerized from acrylic ester monomers, and the acrylic ester monomers include one or more of monofunctional acrylic ester monomers, difunctional acrylic ester monomers and trifunctional acrylic ester monomers.

[0060] The isocyanate in the isocyanate-extended polyol in component B 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 their respective isocyanate monomers; the polyol is at least any one of a small molecule alcohol with a functionality of more than two, a polyester polyol, a polyether polyol and a polycaprolactone polyol, preferably a polyester polyol or a polyether polyol.

[0061] On the other hand, the present invention provides a method for preparing a two-component solvent-free polyurethane adhesive, wherein the component A and the component B are mixed in a certain proportion, wherein the free isocyanate in the component A accounts for 0-1% of the total mass of the polyurethane prepolymer in the component A; and the concentration of the urethane in the two components AB is adjusted to be 0.05-0.5 mol / 100g, to obtain the two-component solvent-free polyurethane adhesive.

[0062] Specifically, the component A and the component B are mixed according to a molar ratio of NCO content in component A to OH content in component B of 1.5 to 1.9, for example, 1.5, 1.55, 1.6, 1.65, 1.7, 1.75, 1.8, 1.85, 1.9, preferably 1.8-1.9; and the free isocyanate in component A is controlled to account for 0-1% of the total mass of the polyurethane prepolymer in component A; the concentration of carbamate in components AB is 0.05-0.5 mol / 100g.

[0063] There is no particular limitation on the specific control method, and conventional technical means in the art may be used, such as controlling the content of free isocyanate in component A by treating component A with a thin film evaporation device, but the method is not limited thereto. In addition, after the components AB are mixed, the concentration of carbamate can only reach a part of the theoretical value due to the insufficient reactivity of a certain isocyanate or polyol. In this case, the carbamate content can be further increased to a range of 0.05-0.5 mol / 100 g by increasing the aging temperature after mixing and increasing the ambient humidity.

[0064] The above mixing steps can refer to the existing technology, for example, mixing and stirring at the same time to make the two materials mixed evenly. There is no restriction on the specific stirring speed and duration, as long as the two components A and B are mixed evenly. The stirring equipment can also use the equipment or stirring tools commonly used in the field.

[0065] The present invention is further described below by more specific examples, but the scope of the present invention is not limited in any way.

[0066] The raw materials used in the embodiments and comparative examples are as follows:

[0067] Polyether:

[0068] Polyether 1: DL-400, polyoxypropylene glycol, molecular weight 400, produced by Shandong Bluestar Dongda Co., Ltd.;

[0069] Polyether 2: DL-1000D, polyoxypropylene glycol, molecular weight 1000, produced by Shandong Bluestar Dongda Co., Ltd.;

[0070] Polyether 3: DL-4000D, polyoxypropylene glycol, molecular weight 4000, produced by Shandong Bluestar Dongda Co., Ltd.;

[0071] Polyether 4: DMN400, polyoxypropylene triol, molecular weight 400, produced by Zibo Dexin Federal Corporation;

[0072] Polyether 5: DMN1000, polyoxypropylene triol, molecular weight 1000, produced by Zibo Dexin Federal Company.

[0073] Polyester polyols:

[0074] Polyester 1: XCPA-195, polyester polyol, hydroxyl value 200, Asahikawa Chemical;

[0075] Polyester 2: XCPA-110, polyester polyol, hydroxyl value 112, Asahikawa Chemical.

[0076] Small molecule alcohol:

[0077] Small molecule alcohol 1: diethylene glycol, Aladdin;

[0078] Small molecule alcohol 2: dipropylene glycol, Aladdin;

[0079] Small molecule alcohol 3: trimethylolpropane, Aladdin.

[0080] Isocyanates:

[0081] Isocyanate 1: WANNATE TDI-100, NCO% = 48.2wt%, produced by Wanhua Chemical Group Co., Ltd.;

[0082] Isocyanate 2: WANNATE MDI-50, NCO% = 33.5wt%, produced by Wanhua Chemical Group Co., Ltd.;

[0083] Isocyanate 3: WANNATE IPDI, NCO% = 37.50wt%, produced by Wanhua Chemical Group Co., Ltd.;

[0084] Isocyanate 4: WANNATE HMDI, NCO% = 31.8wt%, produced by Wanhua Chemical Group Co., Ltd.;

[0085] Isocyanate 5: WANNATE XR-2005 (m-xylylene diisocyanate), NCO% = 44 wt%, produced by Wanhua Chemical Group Co., Ltd.;

[0086] Isocyanate 6: WANNATE HT-100, NCO% = 22wt%, mass fraction of HDI monomer ≤ 0.2%, produced by Wanhua Chemical Group Co., Ltd.;

[0087] Isocyanate 7: WANNATE HB-200, NCO% = 22wt%, mass fraction of HDI monomer ≤ 0.5%, produced by Wanhua Chemical Group Co., Ltd.;

[0088] The test method involved in the embodiment is as follows:

[0089] Free isocyanate monomer content: Tested using liquid chromatography equipment. First, use isocyanate standards of different concentrations to establish a standard curve, and then test the free isocyanate monomer content in the sample;

[0090] NCO test method: Test according to GB / T 12009.4-2016 Aromatic isocyanates for the production of plastic polyurethane Part 4: Determination of isocyanate content;

[0091] Test method for hydroxyl value: Test in accordance with GB / T 12008.3-2009 Plastic polyether polyols Part 3: Determination of hydroxyl value;

[0092] The test method of peel strength is as follows: the sample film is cut into strips with a width of 15 mm, and then the strips are tested using a peeling machine in accordance with the standard GB / T 8808-1988.

[0093] Determination of carbamate content: Use infrared spectrometer to test. First, use carbamate samples with different contents to establish a standard curve, and then test the carbamate content in the sample.

[0094] Preparation of component A:

[0095] Put isocyanate into the reaction device, add polyol raw material, increase stirring, heat to 80±5℃, react for 2 hours, cool to 50℃, and then get a modified isocyanate component with high free monomer. Then, remove the monomer through thin film evaporation equipment to get a modified isocyanate component with low free monomer.

[0096] Table 1A Component formulation

[0097]

[0098] Preparation of component B:

[0099] Put all the raw materials into the reaction device, heat it to 80±5°C, cool it to 40°C after 2 hours, and then discharge the material to obtain component B.

[0100] Table 2B Component formulation

[0101]

[0102]

[0103] Preparation of performance test samples:

[0104] Component A and component B are mixed in a certain ratio, with a mol ratio of NCO / OH of R = 1.5-1.9, and composite OPP / CPP film. The composite film is aged in a 40℃ curing room for 48 hours, and the carbamate content in the glue is tested after being taken out to compare whether the carbamate content falls within the target value range. For composite film materials with large deviations, the method of continuing to mature is adopted, and the conditions for continued maturation are: 50℃ / 60%RH, and the curing is carried out until the target value is reached, and then the peel strength test is carried out.

[0105] The peel strength test was carried out in accordance with the standard GB / T 8808-1988.

[0106] Table 3 Composite membrane test data

[0107]

[0108]

[0109] From the results in Table 3, it can be seen that Examples 1-10 can bond OPP / CPP, but the peel strength of the composite OPP / CPP of Comparative Examples 1 and 2 is much lower than that of Examples 1-10, and there is almost no bonding strength. This is because the carbamate content in Comparative Example 1 is too high, resulting in excessive cohesion of the glue itself, which has an adverse effect on bonding; the carbamate content in Comparative Example 2 is too low, which has no effect on bonding.

[0110] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as limiting the present invention. Those skilled in the art will appreciate that, under the guidance of this specification, some modifications or adjustments may be made to the present invention. These modifications or adjustments should also be within the scope defined by the claims of the present invention.

Claims

1. A two-component solvent-free polyurethane adhesive, comprising component A and component B, characterized in that: The component A is a modified isocyanate with an isocyanate terminal group, and the free isocyanate in the component A accounts for 0-1% of the total mass of the polyurethane prepolymer in the component A; the component B is a polyhydroxy compound, including one or more of small molecule alcohols, polyether polyols, polyester polyols, polycaprolactone polyols, polyether ester polyols, polycarbonate polyols, bio-based polyols, epoxy resins, acrylic polyols and isocyanate-extended polyols; and the concentration of carbamate in the two components A and B is 0.05-0.5 mol / 100g.

2. The polyurethane adhesive according to claim 1, characterized in that: The free isocyanate in the A component accounts for 0-0.5% of the total mass of the polyurethane prepolymer in the A component, preferably 0-0.1%.

3. The polyurethane adhesive according to claim 1 or 2, characterized in that: The modified isocyanate with an isocyanate terminal group in the component A is one or more of a polyisocyanate copolymer, a polyisocyanate biuret and a polyol-modified isocyanate.

4. The polyurethane adhesive according to claim 3, 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-modified isocyanate is formed by the reaction of a polyol and a polyisocyanate-based compound; Preferably, the polyisocyanate-based compound is selected from at least one of aromatic polyisocyanates, aliphatic polyisocyanates, and alicyclic polyisocyanates; More preferably, 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, xylylene diisocyanate, cyclohexane dimethylene diisocyanate, hexamethylene diisocyanate, homopolymers of various isocyanate monomers, and biuret of various isocyanate monomers.

5. The polyurethane adhesive according to claim 4, characterized in that: 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 acrylate polyols; Preferably, the polycaprolactone polyol is a polyol obtained by ring-opening polymerization of caprolactone; and / or Preferably, the polycarbonate polyol is a polyol containing carbonate groups; and / or Preferably, the polyetherester polyol is a polyol containing both a polyether segment and an ester bond (-CO-O-); and / or Preferably, the bio-based polyol is composed of one or more of castor oil, soybean oil, palm oil, rosin esters and their derivatives; and / or Preferably, the epoxy resin is at least one 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 Preferably, the acrylic ester polyol is polymerized from acrylic ester monomers, and the acrylic ester monomers include one or more of monofunctional acrylic ester monomers, difunctional acrylic ester monomers and trifunctional acrylic ester monomers.

6. The polyurethane adhesive according to claim 5, characterized in that: The small molecule polyol is selected from one or more polyols having a molecular weight of 100-2000 and containing more than two hydroxyl groups; Preferably, 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, neopentyl glycol, 1,3-butanediol, 2-ethyl-1,3-hexanediol, 1,2-octanediol, glycerol and trimethylolpropane.

7. The polyurethane adhesive according to claim 1, characterized in that: The small molecule polyol is selected from one or more polyols having a molecular weight of 100-2000 and containing more than two hydroxyl groups; and / or The polyether polyol is selected from at least one of polypropylene oxide, propylene oxide ethylene oxide copolymer, and hydroxyl-terminated oligomers of polytetrahydrofuran; 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; and / or The polycaprolactone polyol is a polyol obtained by ring-opening polymerization of caprolactone; and / or The polycarbonate polyol is a polyol containing a carbonate group (—O—CO—O—); and / or The polyetherester polyol is a polyol containing both a polyether segment and an ester bond (-CO-O-); and / or The bio-based polyol is composed of one or more of castor oil, soybean oil, palm oil, rosin esters and derivatives thereof; and / or The epoxy resin is at least one 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 in component B 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 their respective isocyanate monomers; the polyol is at least any one of a small molecule alcohol with a functionality of more than two, a polyester polyol, a polyether polyol and a polycaprolactone polyol, preferably a polyester polyol or a polyether polyol.

8. The 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, neopentyl glycol, 1,3-butanediol, 2-ethyl-1,3-hexanediol, 1,2-octanediol, glycerol and trimethylolpropane; and / or The polyether polyol is a hydroxyl-terminated oligomer of polypropylene oxide, preferably a polyether polyol with a molecular weight of 400-2000; and / or The dibasic acid in the polyester polyol is selected from one or more of adipic acid, isophthalic acid, terephthalic acid, phthalic anhydride, and sebacic acid; 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; preferably, the molecular weight of the polyester polyol is 400-1000; and / or The epoxy resin is at least one 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 polymerized from acrylic ester monomers, and the acrylic ester monomers include one or more of monofunctional acrylic ester monomers, difunctional acrylic ester monomers and trifunctional acrylic ester monomers.

9. The method for preparing the two-component solvent-free polyurethane adhesive according to any one of claims 1 to 8, characterized in that: The component A and the component B are mixed in proportion to prepare adhesive, wherein the free isocyanate in the component A accounts for 0-1% of the total mass of the polyurethane prepolymer in the component A; and the concentration of the urethane in the two components AB is adjusted to be 0.05-0.5 mol / 100g, to obtain the two-component solvent-free polyurethane adhesive.

10. A polyurethane product, prepared from a composition comprising the two-component solvent-free polyurethane adhesive according to any one of claims 1 to 8 or the two-component solvent-free polyurethane adhesive prepared by the preparation method according to claim 9.

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