Polyurethane adhesive as well as preparation method and application thereof

Abstract

The invention discloses a polyurethane adhesive and a preparation method and application thereof, the polyurethane adhesive comprises a component A and a component B, and does not contain a catalyst component; the component A is modified isocyanate of which the end group is isocyanate, and comprises one or more of a polyisocyanate copolymer, polyisocyanate biuret and polyol modified isocyanate; the component B is a polyhydroxy compound and comprises one or more of small molecular alcohol, polyether polyol, polyester polyol, polycaprolactone polyol, polyether ester polyol, polycarbonate polyol, bio-based polyol, epoxy resin, acrylate polyol and isocyanate chain-extended polyol; and at least one of the polyhydric alcohols in the component A and the component B is a treated polyhydric alcohol with a CPR value of 0.1-3. According to the polyurethane adhesive disclosed by the invention, the overall soft and hard segment structure of the adhesive is adjusted by controlling the CPR, so that the adhesive which does not need a catalyst and has good adhesive performance is obtained, and the adhesive has good curing performance.

Description

Technical Field

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

[0002] As people's living standards continue to improve, people's quality requirements for daily necessities are getting higher and higher. For example, in the food packaging industry, there is an increasing demand for yellowing resistance and low-temperature freezing. At present, there are solvent-based adhesives, water-based adhesives and solvent-free adhesives in the soft packaging industry. Solvent-based adhesives account for the largest share in the market, but with the increase in environmental protection efforts, solvent-based adhesives are gradually replaced by solvent-free adhesives. The isocyanates contained in solvent-based adhesives and solvent-free adhesives are mainly aromatic isocyanates, which are not resistant to yellowing in nature and are easy to crystallize at low temperatures, resulting in low peel strength at low temperatures. Aliphatic isocyanates have good yellowing resistance and have a lower crystallization temperature than aromatic isocyanates, making them more suitable for use in low-temperature environments. However, aliphatic isocyanates are significantly lower in reactivity than aromatic isocyanates. In the industry, when using aliphatic isocyanates, an appropriate amount of catalyst is generally added to shorten the aging time of adhesives containing aliphatic isocyanates.

[0003] Chinese patent application CN 102295906B discloses a high-strength, yellowing-resistant elastic polyurethane adhesive and its preparation method and application. The isocyanate used in the polyurethane adhesive includes one or more of HDI isocyanate, HMDI isocyanate or IPDI isocyanate, and the catalyst selected includes bis(dimethylaminoethyl) ether, organic bismuth catalyst, organic zinc catalyst or organic tin catalyst. The polyurethane adhesive prepared by combining polyol resin, thixotropic agent and coupling agent can have excellent adhesion to both glass and plastic, can be quickly cured by heating, can withstand high temperature of 150°C for a long time and has no yellowing phenomenon.

[0004] Chinese patent application CN 102911636B discloses a two-component polyurethane adhesive and its preparation method and application. The polyurethane adhesive uses any one or a combination of toluene cyclohexylene diisocyanate (HTDI), 4,4'-bis(isocyanate cyclohexane) methane (HMDI), xylene diisocyanate (XDI), hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexane diisocyanate (TMDI), 2,6-diisocyanate methylhexanoate (LDIM), with refined and hydrogenated castor oil, a catalyst (any one or a combination of amine catalysts and organometallic catalysts), and other additives to prepare a polyurethane adhesive with strong corrosion resistance and weather resistance, high stability, good melt fluidity, high bonding strength, good sealing performance, and no yellowing.

[0005] The use of catalysts can solve the problem of aliphatic isocyanate adhesives aging, but it also brings food safety risks. The national standard GB 9685-2016 "National Food Safety Standard for the Use of Additives in Food Contact Materials and Products" has limited requirements for a variety of metal elements. If they are not in the catalog, the migration amount must not exceed 10ppb. Therefore, developing a polyurethane adhesive with good aging performance without the use of catalysts is an urgent issue that the industry needs to solve. Summary of the invention

[0006] The object of the present invention is to overcome the above-mentioned deficiencies of the prior art and to provide a polyurethane adhesive which can effectively improve the bonding performance and the curing performance by controlling the CPR value of the polyether without adding a catalyst.

[0007] Another object of the present invention is to provide a method for preparing the polyurethane adhesive.

[0008] Another object of the present invention is to provide the use of the polyurethane adhesive in preparing polyurethane products.

[0009] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0010] A polyurethane adhesive comprises a component A and a component B, and does not contain a catalyst component; the component A is a modified isocyanate having an isocyanate terminal group, comprising one or more of a polyisocyanate copolymer, a polyisocyanate biuret and a polyol-modified isocyanate; the component B is a polyhydroxy compound, comprising one or more of a small molecule alcohol, a polyether polyol, a polyester polyol, a polycaprolactone polyol, a polyether ester polyol, a polycarbonate polyol, a bio-based polyol, an epoxy resin, an acrylate polyol and an isocyanate-chain-extended polyol; and at least one of the polyols in the components A and B is a treated polyol having a CPR value of 0.1-3, preferably a polyol having a CPR value of 1-3.

[0011] 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.

[0012] 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.

[0013] In a specific embodiment, 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.

[0014] 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.

[0015] In a specific embodiment, the polycaprolactone polyol is a polyol obtained by ring-opening polymerization of caprolactone.

[0016] In a specific embodiment, the polycarbonate polyol is a polyol containing carbonate groups.

[0017] In a specific embodiment, the polyetherester polyol is a polyol containing both a polyether segment and an ester bond (—CO—O—).

[0018] 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.

[0019] 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.

[0020] 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.

[0021] In a specific embodiment, the small molecule polyol in component B 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.

[0022] In a specific embodiment, the polyether polyol in component B is selected from at least any one of polypropylene oxide, propylene oxide ethylene oxide copolymer, and hydroxyl-terminated oligomer of polytetrahydrofuran, preferably a hydroxyl-terminated oligomer of polypropylene oxide, and more preferably a polyether polyol with a molecular weight of 400-2000.

[0023] In a specific embodiment, the polyester polyol in component B is a hydroxyl-terminated oligomer obtained by a polymer condensation polymerization reaction of a dibasic acid and a polyol, wherein 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.

[0024] In a specific embodiment, the polycaprolactone polyol in the B component is a polyol obtained by ring-opening polymerization of caprolactone.

[0025] In a specific embodiment, the polycarbonate polyol in the B component is a polyol containing a carbonate group (—O—CO—O—).

[0026] In a specific embodiment, the polyether ester polyol in the B component is a polyol containing both a polyether segment and an ester bond (—CO—O—).

[0027] In a specific embodiment, the bio-based polyol in the B component consists of one or more of castor oil, soybean oil, palm oil, rosin esters and derivatives thereof.

[0028] In a specific embodiment, the epoxy resin in the B component 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.

[0029] In a specific embodiment, the acrylic ester polyol in the B component 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.

[0030] 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 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.

[0031] 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.

[0032] 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 a certain proportion to obtain the polyurethane adhesive; wherein at least one of the polyols in the two components A and B is a treated polyol with a CPR value of 0.1-3; preferably, the polyol is treated with acid so that the CPR value of the polyol is 0.1-3.

[0033] On the other hand, the aforementioned polyurethane adhesive or the polyurethane adhesive prepared by the aforementioned preparation method is used in the preparation of polyurethane products.

[0034] The present invention achieves the following beneficial effects by adopting the above technical solution:

[0035] The two-component solvent-free polyurethane adhesive of the present invention can effectively reduce the aging time of the adhesive and improve the terminal application efficiency by controlling the CPR of the polyol therein without using a catalyst, thereby avoiding the food safety hazards caused by the introduction of metal ions by the catalyst. At the same time, the low-free polyisocyanate compound can provide construction workers with a safer and more environmentally friendly use experience. DETAILED DESCRIPTION

[0036] 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.

[0037] A polyurethane adhesive, comprising component A and component B, and containing no catalyst component; wherein the component A is a modified isocyanate having an isocyanate terminal group, comprising one or more of a polyisocyanate copolymer, a polyisocyanate biuret and a polyol-modified isocyanate; the component B is a polyhydroxy compound, comprising one or more of a small molecule alcohol, a polyether polyol, a polyester polyol, a polycaprolactone polyol, a polyether ester polyol, a polycarbonate polyol, a bio-based polyol, an epoxy resin, an acrylate polyol and an isocyanate-extended polyol; and At least one of the polyols in components A and B is a treated polyol with a CPR value of 0.1-3, preferably a polyol with a CPR of 1-3, for example, a CPR of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, etc., but not limited thereto.

[0038] Among them, CPR is the abbreviation of the content of alkaline substances in polyols. The testing method of CPR value is described in detail below. Among common polyols, such as polyether polyols, polycarbonate polyols, polyether ester polyols, alkali-treated bio-based polyols, epoxy resins and some small molecule alcohols are usually alkaline and have CPR values; while polyester polyols, some small molecule polyols, etc. are usually acidic and do not have the CPR value of the present invention. This is usually related to the preparation process of polyols. Alkaline substances (such as alkali) are added during the preparation process, and they usually have CPR values; on the contrary, if acidic substances are added, they do not have the CPR value of the present invention. The higher the CPR value, the higher the content of alkaline substances in the polyol. Taking polyether polyols as an example, the CPR value of polyether polyols can be reduced by acid treatment, for example, by acid treatment by adding phosphoric acid to reduce the CPR to the target range.

[0039] 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. 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-based compound.

[0040] 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.

[0041] The polyol 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.

[0042] The small molecule polyol is selected from one or more polyols with 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.

[0043] The polycaprolactone polyol is a polyol obtained by ring-opening polymerization of caprolactone.

[0044] The polycarbonate polyol is a polyol containing carbonate groups.

[0045] The polyetherester polyol is a polyol containing both a polyether segment and an ester bond (-CO-O-).

[0046] The bio-based polyol is composed of one or more of castor oil, soybean oil, palm oil, rosin ester and derivatives thereof.

[0047] 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.

[0048] 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.

[0049] In the present invention, the modified isocyanate whose terminal group of component A is isocyanate can be prepared by conventional methods in the art, such as conventional one-step method or step-by-step method, and specific examples are as follows:

[0050] One-step method: put isocyanate into the reaction device, add polyol raw material, increase stirring, raise the temperature to 80±5℃, react for 2 hours, cool to 50℃ and discharge to obtain modified isocyanate component.

[0051] Step-by-step method: put isocyanate 1 into the reaction device, add the polyol raw material, increase the stirring, raise the temperature to 80±5℃, react for 2 hours, then add isocyanate 2, continue to react for 2 hours, cool down to 50℃ and obtain the modified isocyanate component.

[0052] The B component is a polyhydroxy compound, preferably 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.

[0053] The small molecule polyol is selected from one or more polyols with 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.

[0054] 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.

[0055] 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.

[0056] The polycaprolactone polyol is a polyol obtained by ring-opening polymerization of caprolactone.

[0057] The polycarbonate polyol is a polyol containing a carbonate group (—O—CO—O—).

[0058] The polyetherester polyol is a polyol containing both a polyether segment and an ester bond (-CO-O-).

[0059] The bio-based polyol is composed of one or more of castor oil, soybean oil, palm oil, rosin ester and derivatives thereof.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] The component A and the component B are mixed in a certain proportion, and the R value (NCO / OH molar ratio) is usually controlled to be 1.8-1.9 to obtain the polyurethane adhesive; wherein at least one of the polyols in the components A and B is a pre-treated polyol with a CPR value of 0.1-3; preferably, the polyol is acid-treated so that the CPR value of the polyol is 0.1-3.

[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] Polyester polyols:

[0068] Polyester polyol 1: XCPA-195, polyester polyol, hydroxyl value 200, Asahikawa Chemical.

[0069] Isocyanates:

[0070] Isocyanate 1: WANNATE TDI-100, NCO% = 48.2wt%, Wanhua Chemical Group Co., Ltd.;

[0071] Isocyanate 2: WANNATE MDI-50, NCO% = 33.5wt%, Wanhua Chemical Group Co., Ltd.;

[0072] Isocyanate 3: WANNATE IPDI, NCO% = 37.50wt%, Wanhua Chemical Group Co., Ltd.;

[0073] Isocyanate 4: WANNATE HMDI, NCO% = 31.8wt%, Wanhua Chemical Group Co., Ltd.;

[0074] Isocyanate 5: WANNATE XR-2005 (m-xylylene diisocyanate), NCO% = 44 wt%, Wanhua Chemical Group Co., Ltd.;

[0075] Isocyanate 6: WANNATE HT-100, NCO% = 22wt%, mass fraction of HDI monomer ≤ 0.2%, Wanhua Chemical Group Co., Ltd.;

[0076] Isocyanate 7: WANNATE HB-200, NCO%=23.3wt%, mass fraction of HDI monomer ≤0.5%, produced by Wanhua Chemical Group Co., Ltd.

[0077] Preparation of polyether polyols:

[0078] Polyether polyol 1: Add 130g of ethylene glycol and 2g of KOH as initiators to the reactor, and then dehydrate at 100°C and a relative pressure of -0.1MPa for 60min. Then, heat to 110°C, relative pressure of 0.3MPa, add propylene oxide dropwise, add propylene oxide to 870g, and age for 3h. Vacuum to remove unreacted residual monomers and small molecular by-products. Cool the temperature in the reactor to 60°C, add nitrogen to make the relative pressure in the reactor 0MPa, add 100g of water, 4g of magnesium silicate and an appropriate amount of phosphoric acid (85% mass fraction) to the reactor, stir for 30min, vacuum dehydrate to a water content of ≤0.05%, sample and test CPR to 3.6, continue to add phosphoric acid until the CPR is adjusted to 1.9. Filter to obtain polyether polyol 1 with a number average molecular weight of 400 and a CPR of 1.9.

[0079] Polyether polyol 2: Add 34g of ethylene glycol and 2g of KOH as initiators to the reactor, and then dehydrate at 100°C and a relative pressure of -0.1MPa for 60min. Then, raise the temperature to 110°C and a relative pressure of 0.3MPa, add propylene oxide dropwise, add propylene oxide to 966g, and age for 3h. Vacuum off the unreacted residual monomers and small molecular by-products. Cool the temperature in the reactor to 60°C, add nitrogen to make the relative pressure in the reactor 0MPa, add 100g of water, 4g of magnesium silicate and an appropriate amount of phosphoric acid (85%) to the reactor, stir for 30min, vacuum dehydrate to a water content of ≤0.05%, take a sample and test the CPR to be 1.2, continue to add phosphoric acid until the CPR is adjusted to 0.05. Filter to obtain polyether polyol 2 with a number average molecular weight of 1000 and a CPR of 0.05.

[0080] Polyether polyol 3: Add 34g of ethylene glycol and 2g of KOH as initiators to the reactor, and then dehydrate at 100°C and a relative pressure of -0.1MPa for 60min. Then, raise the temperature to 110°C and a relative pressure of 0.3MPa, add propylene oxide dropwise, add propylene oxide to 966g, and age for 3h. Vacuum off the unreacted residual monomers and small molecular by-products. Cool the temperature in the reactor to 60°C, add nitrogen to make the relative pressure in the reactor 0MPa, add 100g of water, 4g of magnesium silicate and an appropriate amount of phosphoric acid (85%) to the reactor, stir for 30min, vacuum dehydrate to a water content of ≤0.05%, take a sample and test the CPR to be 0.8, continue to add phosphoric acid until the CPR is adjusted to 0.1. Filter to obtain polyether polyol 3 with a number average molecular weight of 1000 and a CPR of 0.1.

[0081] Polyether polyol 4: Add 34g of ethylene glycol and 2g of KOH as initiators to the reactor, and then dehydrate at 100°C and a relative pressure of -0.1MPa for 60min. Then, raise the temperature to 110°C and a relative pressure of 0.3MPa, add propylene oxide dropwise, add propylene oxide to 966g, and age for 3h. Vacuum off the unreacted residual monomers and small molecular by-products. Cool the temperature in the reactor to 60°C, add nitrogen to make the relative pressure in the reactor 0MPa, add 100g of water, 4g of magnesium silicate and an appropriate amount of phosphoric acid (85%) to the reactor, stir for 30min, vacuum dehydrate to a water content of ≤0.05%, take a sample and test the CPR to be 1.6, continue to add phosphoric acid until the CPR is adjusted to 1. Filter to obtain polyether polyol 4 with a number average molecular weight of 1000 and a CPR of 1.

[0082] Polyether polyol 5: Add 34g of ethylene glycol and 2g of KOH as initiators to the reactor, and then dehydrate at 100°C and a relative pressure of -0.1MPa for 60min. Then, raise the temperature to 110°C and a relative pressure of 0.3MPa, add propylene oxide dropwise, add propylene oxide to 966g, and age for 3h. Vacuum off the unreacted residual monomers and small molecular by-products. Cool the temperature in the reactor to 60°C, add nitrogen to make the relative pressure in the reactor 0MPa, add 100g of water, 4g of magnesium silicate and an appropriate amount of phosphoric acid (85%) to the reactor, stir for 30min, vacuum dehydrate to a water content of ≤0.05%, take a sample and test the CPR to be 2.7, continue to add phosphoric acid until the CPR is adjusted to 2. Filter to obtain polyether polyol 5 with a number average molecular weight of 1000 and a CPR of 2.

[0083] Polyether polyol 6: Add 34g of ethylene glycol and 2g of KOH as initiators to the reactor, and then dehydrate at 100°C and a relative pressure of -0.1MPa for 60min. Then, raise the temperature to 110°C and a relative pressure of 0.3MPa, add propylene oxide dropwise, add propylene oxide to 966g, and age for 3h. Vacuum off the unreacted residual monomers and small molecular by-products. Cool the temperature in the reactor to 60°C, add nitrogen to make the relative pressure in the reactor 0MPa, add 100g of water, 4g of magnesium silicate and an appropriate amount of phosphoric acid (85%) to the reactor, stir for 30min, vacuum dehydrate to a water content of ≤0.05%, take a sample and test the CPR to be 3.9, continue to add phosphoric acid until the CPR is adjusted to 3. Filter to obtain polyether polyol 6 with a number average molecular weight of 1000 and a CPR of 3.

[0084] Polyether polyol 7: Add 34g of ethylene glycol and 2g of KOH as initiators to the reactor, and then dehydrate at 100°C and a relative pressure of -0.1MPa for 60min. Then, raise the temperature to 110°C and a relative pressure of 0.3MPa, add propylene oxide dropwise, add propylene oxide to 966g, and age for 3h. Vacuum off the unreacted residual monomers and small molecular by-products. Cool the temperature in the reactor to 60°C, add nitrogen to make the relative pressure in the reactor 0MPa, add 100g of water, 4g of magnesium silicate and an appropriate amount of phosphoric acid (85%) to the reactor, stir for 30min, vacuum dehydrate to a water content of ≤0.05%, take a sample and test the CPR to be 4.1, continue to add phosphoric acid until the CPR is adjusted to 3.5. Filter to obtain polyether polyol 7 with a number average molecular weight of 1000 and a CPR of 3.5.

[0085] Polyether polyol 8: Add 210g of glycerol and 2g of KOH as initiators to the reactor, and then dehydrate at 100°C and a relative pressure of -0.1MPa for 60min. Then, raise the temperature to 110°C and a relative pressure of 0.3MPa, add propylene oxide dropwise, add propylene oxide to 770g, and age for 3h. Vacuum off the unreacted residual monomers and small molecular by-products. Cool the temperature in the reactor to 60°C, add nitrogen to make the relative pressure in the reactor 0MPa, add 100g of water, 4g of magnesium silicate and an appropriate amount of phosphoric acid (85%) to the reactor, stir for 30min, vacuum dehydrate to a water content of ≤0.05%, take a sample and test the CPR to be 2.6, continue to add phosphoric acid until the CPR is adjusted to 1.9. Filter to obtain polyether polyol 8 with a number average molecular weight of 1000 and a CPR of 1.9.

[0086] Preparation of polycarbonate polyol 1:

[0087] Polycarbonate polyol 1: Prepared according to Example 1 of the patent CN 110256662 B, carbonate polyol was prepared, and the CPR was 8.7. Then, after heating and melting, deionized water and an appropriate amount of phosphoric acid (85%) were added for washing. After adjusting the CPR value to 2, the water was removed by vacuum to make the water content ≤ 0.05%. The preparation formula is as follows:

[0088] Table 1 Polycarbonate polyol formulation

[0089] Raw material name Mass 1,4-Butanediol 360 Dimethyl carbonate 378 Sodium hydroxide 0.0088 1,8-Diazabicyclo[5.4.0]undec-7-ene 0.00608 Hydroxyl value 81 CPR 2

[0090] The test method involved in the embodiment is as follows:

[0091] CPR value test method: dilute 30g of polyether polyol sample with methanol, then titrate with 0.01mol / L hydrochloric acid standard titration solution, and calculate the result by the titration volume difference between the sample and blank.

[0092]

[0093] C: CPR value;

[0094] V S : The volume of the HCl standard titration solution consumed by the titration sample, in milliliters (mL);

[0095] V B : The volume of HCl standard titration solution consumed in the titration blank, in milliliters (mL);

[0096] M: the molar concentration of the HCl standard titration solution, in moles per liter (mol / l);

[0097] m: The numerical value of the mass of the sample, in grams (g).

[0098] Free isocyanate monomer content: tested using liquid chromatography equipment;

[0099] 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;

[0100] Test method for hydroxyl value: Test in accordance with GB / T 12008.3-2009 Plastic polyether polyols Part 3: Determination of hydroxyl value;

[0101] 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.

[0102] Adhesive dryness test method: if the two laminated films are torn apart and then restored to laminate, and can be completely laminated again, it is "sticky"; if the two laminated films are torn apart and there is obvious stringing, and they can barely be laminated after being restored to laminate, it is "slightly sticky"; if the two laminated films are torn apart and there is only a small amount of stringing, and they can hardly be laminated after being restored to laminate, it is "slightly sticky"; if the two laminated films are torn apart and there is no stringing, and they can hardly be laminated again, it is "dry".

[0103] Preparation of component A:

[0104] A1:

[0105] One-step method: 6.07g of MDI-50 and 64.82g of HT100 were put into the reaction device, 600g of polyether polyol 1 was added, stirring was increased, the temperature was raised to 80±5°C, and after reacting for 2 hours, the temperature was lowered to 50°C to obtain the modified isocyanate component with an NCO value of 10.18.

[0106] A2:

[0107] Step-by-step method: 3.44 g of TDI-100 was added to the reaction device, 43.78 g of polycarbonate polyol 1 was added, stirring was increased, the temperature was raised to 80±5°C, and after reacting for 2 hours, 52.79 g of HT100 was added and the reaction was continued for 2 hours, and the temperature was lowered to 50°C to obtain the modified isocyanate component with an NCO value of 10.61.

[0108] Preparation of component B:

[0109] 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.

[0110] Table 2B Component formulation

[0111]

[0112]

[0113] Preparation of performance test samples:

[0114] Component A and component B are mixed in a certain ratio, and the mol ratio of NCO / OH is R=1.8-1.9, and a PA / CPP film is composited. The composite film is aged in a 50°C aging room for 48 hours, and a peel strength test is performed during the aging process.

[0115] The peel strength test was carried out in accordance with the standard GB / T 8808-1988.

[0116] Table 3 Composite membrane test data

[0117]

[0118] From the results in Table 3, it can be seen that no catalyst was added to Examples 1-11, and the adhesives were all dried after 50℃ / 48h, and the peel strength was greater than 3.5N / 15mm, meeting the national standard requirement of ≥2.0N / 15mm. However, the adhesive of Comparative Example 1 was still not dried after 50℃ / 48h, and the aging rate was slow. Compared with Examples 1-4, the CPR value of polyether polyol 2 in Comparative Example 1 was 0.05, which was less than the CPR value of the polyether in Examples 1-4. The adhesive of Comparative Example 2 was dried after 50℃ / 48h, but the peel strength was only 1.8N / 15mm, which was less than the national standard requirement of 2.0N / 15mm. The CPR value in Comparative Example 2 was 3.5, which was higher than the CPR value of the polyether in Examples 1-4. It is speculated that the CPR value was too high, resulting in too fast aging rate of the adhesive, resulting in excessive cohesion, which reduced the bonding performance of the adhesive to the interface.

[0119] 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 polyurethane adhesive, characterized in that: The invention comprises a component A and a component B, and does not contain a catalyst component; the component A is a modified isocyanate having an isocyanate terminal group, comprising one or more of a polyisocyanate copolymer, a polyisocyanate biuret and a polyol-modified isocyanate; the component B is a polyhydroxy compound, comprising one or more of a small molecule alcohol, a polyether polyol, a polyester polyol, a polycaprolactone polyol, a polyether ester polyol, a polycarbonate polyol, a bio-based polyol, an epoxy resin, an acrylate polyol and an isocyanate-extended polyol; and at least one of the polyols in the two components A and B is a treated polyol having a CPR value of 0.1-3, preferably a polyol having a CPR value of 1-3.

2. The polyurethane adhesive according to claim 1, characterized in that: The polyisocyanate copolymer is selected from aromatic polyisocyanate copolymers, aliphatic polyisocyanate copolymers, alicyclic polyisocyanate copolymers; and / or The polyisocyanate biuret is selected from aromatic polyisocyanate biuret, aliphatic polyisocyanate biuret, alicyclic polyisocyanate biuret; and / or The polyol-modified isocyanate is formed by the reaction of a polyhydroxy compound and a polyisocyanate-based compound; preferably, the polyisocyanate-based compound is selected from at least one of aromatic polyisocyanates, aliphatic polyisocyanates, and aliphatic cyclopolyisocyanates; more 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 biuret of various isocyanate monomers.

3. The polyurethane adhesive according to claim 1 or 2, 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 small molecule polyol is selected from one or more polyols with a molecular weight of 100-2000 containing more than two hydroxyl groups; preferably 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.

4. The polyurethane adhesive according to claim 3, characterized in that: 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 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 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.

5. The polyurethane adhesive according to claim 1, characterized in that: The small molecule polyol in component B 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.

6. The polyurethane adhesive according to claim 1, characterized in that: The polyether polyol in the B component is selected from at least any one of polypropylene oxide, propylene oxide ethylene oxide copolymer, and hydroxyl-terminated oligomer of polytetrahydrofuran, preferably a hydroxyl-terminated oligomer of polypropylene oxide, and more preferably a polyether polyol with a molecular weight of 400-2000.

7. The polyurethane adhesive according to claim 1, characterized in that: The polyester polyol in component B is a hydroxyl-terminated oligomer obtained by polymer condensation polymerization of a dibasic acid and a polyol, wherein 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: and / or The polycaprolactone polyol in the B component is a polyol obtained by ring-opening polymerization of caprolactone; and / or The polycarbonate polyol in the B component is a polyol containing a carbonate group (—O—CO—O—); and / or The polyether ester polyol in the B component is a polyol containing both a polyether segment and an ester bond (-CO-O-); and / or The bio-based polyol in the B component is composed of one or more of castor oil, soybean oil, palm oil, rosin ester and derivatives thereof; and / or The epoxy resin in component B 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 in the B component 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.

8. The polyurethane adhesive according to claim 1, characterized in that: 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 preferably 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, and more preferably a polyester polyol or a polyether polyol.

9. The method for preparing the polyurethane adhesive according to any one of claims 1 to 8, characterized in that: The component A and the component B are mixed in a certain proportion to obtain the polyurethane adhesive; wherein the polyols in the components A and B are treated so that the CPR value of the polyol is 0.1-3; preferably, the polyols are treated with acid so that the CPR value of the polyol is 0.1-3.

10. Use of the polyurethane adhesive according to any one of claims 1 to 8 or the polyurethane adhesive prepared by the preparation method according to claim 9 in the preparation of polyurethane products.

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