CN116875258A - Recyclable polyurethane binder and preparation method and application thereof - Google Patents

Recyclable polyurethane binder and preparation method and application thereof Download PDF

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Publication number
CN116875258A
CN116875258A CN202310622924.4A CN202310622924A CN116875258A CN 116875258 A CN116875258 A CN 116875258A CN 202310622924 A CN202310622924 A CN 202310622924A CN 116875258 A CN116875258 A CN 116875258A
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polyurethane
polyurethane binder
recyclable
hollow glass
heat conducting
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容敏智
张泽平
章明秋
朱敏
肖华
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Sun Yat Sen University
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Sun Yat Sen University
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J175/00—Adhesives based on polyureas or polyurethanes; Adhesives based on derivatives of such polymers
    • C09J175/04—Polyurethanes
    • C09J175/08—Polyurethanes from polyethers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/08—Processes
    • C08G18/10—Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/40—High-molecular-weight compounds
    • C08G18/42—Polycondensates having carboxylic or carbonic ester groups in the main chain
    • C08G18/4266—Polycondensates having carboxylic or carbonic ester groups in the main chain prepared from hydroxycarboxylic acids and/or lactones
    • C08G18/4269—Lactones
    • C08G18/4277—Caprolactone and/or substituted caprolactone
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/40—High-molecular-weight compounds
    • C08G18/48—Polyethers
    • C08G18/4833—Polyethers containing oxyethylene units
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/40—High-molecular-weight compounds
    • C08G18/48—Polyethers
    • C08G18/4854—Polyethers containing oxyalkylene groups having four carbon atoms in the alkylene group
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/65—Low-molecular-weight compounds having active hydrogen with high-molecular-weight compounds having active hydrogen
    • C08G18/66—Compounds of groups C08G18/42, C08G18/48, or C08G18/52
    • C08G18/6633—Compounds of group C08G18/42
    • C08G18/6659—Compounds of group C08G18/42 with compounds of group C08G18/34
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/65—Low-molecular-weight compounds having active hydrogen with high-molecular-weight compounds having active hydrogen
    • C08G18/66—Compounds of groups C08G18/42, C08G18/48, or C08G18/52
    • C08G18/6666—Compounds of group C08G18/48 or C08G18/52
    • C08G18/6692—Compounds of group C08G18/48 or C08G18/52 with compounds of group C08G18/34
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
    • C09J11/02—Non-macromolecular additives
    • C09J11/04—Non-macromolecular additives inorganic
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J175/00—Adhesives based on polyureas or polyurethanes; Adhesives based on derivatives of such polymers
    • C09J175/04—Polyurethanes
    • C09J175/06—Polyurethanes from polyesters

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Inorganic Chemistry (AREA)
  • Adhesives Or Adhesive Processes (AREA)

Abstract

The invention provides a recyclable polyurethane binder, and a preparation method and application thereof. According to the invention, the reversible covalent bond is introduced into the polyurethane molecular chain segment to realize recycling of the polyurethane binder; the reversible covalent bond, the polyester or polyether chain segment and the carboxyl group are combined to improve the bonding performance of the polyurethane adhesive and the metal substrate; the introduction of the phosphate chain segment can not only improve the flame retardant property of polyurethane in a synergistic way with a specific reversible bond, but also can jointly act with the hollow glass bead wrapped by the special combined heat conducting filler, so that the heat resistance of the polyurethane is further improved, and the polyurethane adhesive can obtain higher heat conductivity under the condition of less addition of the heat conducting filler.

Description

Recyclable polyurethane binder and preparation method and application thereof
Technical Field
The invention relates to the technical field of high polymer materials, in particular to a recyclable polyurethane binder, and a preparation method and application thereof.
Background
The lithium ion battery is a novel high-energy battery, and has the advantages of high energy, high voltage, wide working temperature range and the like, so that the lithium ion battery is widely applied to the fields of aerospace, energy storage equipment, electric automobiles and the like. Currently, lithium ion power battery packs have a plurality of stainless steel or aluminum encapsulated cells adhered, fixed and assembled together by an adhesive, which often results in difficult detachment of the adhesive and difficult efficient removal and recycling when recycling the cells.
In addition, the adhesive applied to the battery is required to have high heat conductivity, high flame retardance, high adhesive strength, collision resistance and other performances at the same time, so that the safety and reliability of the power battery are improved, the service life is prolonged, and more complex working environments are dealt with. In order to achieve high thermal conductivity and flame retardancy, it is generally necessary to fill a large amount of inorganic heat conductive filler and flame retardant, which tends to deteriorate the adhesive properties of the adhesive.
Accordingly, it is desirable to provide a recyclable adhesive that has high thermal conductivity, high flame retardancy, high adhesion, and the like.
Disclosure of Invention
The invention aims to overcome the defects that the prior adhesive for the battery is difficult to peel off during recycling and the heat conductivity, the flame retardance and the adhesiveness cannot be improved simultaneously, and provides the adhesive which has high heat conductivity, high flame retardance and high adhesiveness and can be recycled.
Another object of the present invention is to provide a method for preparing the binder.
It is a further object of the present invention to provide the use of said binder in the preparation of batteries.
In order to achieve the above purpose, the invention adopts the following technical scheme:
the recyclable polyurethane binder comprises the following components in parts by weight:
the polyurethane of the present invention:
1) Reversible covalent bonds are introduced, and can be rearranged in a network topology structure under external stimulus (such as light, heat and water), so that intrinsic self-repairing, solid-phase recovery, solution degradation, injection molding, extrusion molding and the like are realized, and polyurethane binder in the battery can be stripped, recovered and reused under the external stimulus. Meanwhile, the self-adaptive characteristic brought by homolytic cleavage-combination of the reversible bond is beneficial to closer adhesion between the polymer and the substrate, and the interfacial adhesion of the polyurethane adhesive is improved. In addition, both boron and nitrogen elements in the specific reversible bond types (e.g., borate and imine bonds) can form synergistic flame retardant effects with phosphate esters.
2) The polyester or polyether chain segment with good flexibility and proper crystallinity is introduced to be matched with the isocyanate hard segment with certain rigidity, and the reversible covalent bond and the hydrogen bond formed in polyurethane molecules are combined to cooperate, so that the mechanical strength and fracture toughness of the polyurethane adhesive can be obviously improved, and the polyurethane and the base material have good adhesive property.
3) The phosphate chain segment with flame retardant property is introduced, and the phosphate chain segment is connected into the polyurethane macromolecular chain segment, so that the flame retardant property is more durable, the compatibility problem is avoided, migration is avoided, and the mechanical property of the polyurethane binder is not adversely affected; meanwhile, the inventors of the present invention have unexpectedly found that the combination of a phosphate segment containing a biphenyl ring and a cyclic o=p-O bond with a conventional polyurethane segment can increase the rigidity of a macromolecular chain and the crystallization of a hard block, thereby further improving the heat resistance of a polyurethane binder.
4) Carboxyl is also introduced, and is a polar group, which can form coordination bond with metal substrate in the battery to improve the polymerizationThe adhesion performance of the urethane adhesive and the metal substrate; meanwhile, the carboxyl can increase the hydrophilicity of the material, so that the wetting of the aqueous solution to the polyurethane adhesive is facilitated when the solution is degraded, and the degradation effect of the aqueous solution is improved; in addition, because the oxygen content of the acidic carboxyl is high, the material can be dehydrated to carbon when the base material burns, and the CO can be catalyzed to be converted into CO 2 Further improving the flame retardant and smoke suppression and toxicity reduction performances of the polyurethane adhesive.
5) The heat-conducting filler is wrapped on the surfaces of the hollow glass beads, so that the hollow glass beads are low in density and have better fluidity in a polyurethane system; and the hollow structure and the space limiting function are beneficial to the forced contact of the heat conducting filler on the surface of the polyurethane adhesive to form a certain heat conducting path, so that the filling quantity of the heat conducting filler is further reduced, and the influence of the heat conducting filler on the adhesive property of the polyurethane adhesive is reduced.
According to the invention, the reversible covalent bond is introduced into the polyurethane molecular chain segment to realize recycling of the polyurethane binder; the reversible covalent bond, the polyester or polyether chain segment and the carboxyl group are combined to improve the bonding performance of the polyurethane adhesive and the metal substrate; the introduction of the phosphate chain segment improves the flame retardant property of polyurethane; in addition, the combination mode of the heat conducting filler and the hollow glass beads can generate a synergistic effect, and the polyurethane adhesive can obtain higher heat conductivity under the condition of less addition amount of the heat conducting filler; the inorganic heat conducting filler wrapped on the surface of the hollow glass microsphere can further improve the heat resistance of the polyurethane adhesive by adsorbing the macromolecular chain segment and coacting with the phosphate chain segment on the polyurethane chain, so that the attenuation of the bonding strength at high temperature is avoided.
The reversible covalent bond can be mainly constructed through reversible addition reactions (such as Diels-Alder bonds, urea bonds and thiourea bonds), reversible condensation reactions (such as imine bonds and boric acid ester bonds), redox reactions (such as disulfide bonds) and free radical coupling reactions (such as alkoxyamine and aromatic pinacol), wherein the reversible bonds of the condensation type can realize reversible hydrolytic balance under the excitation of water, and a green, low-carbon and environment-friendly controllable degradation recovery way is provided for the crosslinked polymer. Thus, in embodiments of the present invention, the reversible covalent bond is preferably a borate bond and/or an imine bond in the diol monomer containing the reversible covalent bond. The boric acid ester bond and the imine bond are hydrolyzable bonds, under the stimulation of water, the crosslinking network structure can be de-crosslinked through hydrolytic balance, the polyurethane bond can be recovered in aqueous solution (for example, the polyurethane bond is soaked in aqueous solution with the temperature of 25-50 ℃ and is assisted to be stirred or is treated by ultrasonic for 24-120 hours), and the method has the characteristics of simplicity in operation, no organic solvent, environment friendliness and energy conservation, and is easy to popularize in a large scale, so that the reversible covalent bond is preferably the boric acid ester bond and the imine bond.
In the present invention, the diol monomer having a reversible covalent bond may be one type of diol monomer having a reversible covalent bond, or may be a mixed monomer of a plurality of types of monomers having a reversible covalent bond.
When the reversible covalent bond is a borate ester bond, the diol monomer containing the reversible covalent bond includes at least one of the following structural formulas:
when the reversible covalent bond is an imine bond, the diol monomer containing the reversible covalent bond includes at least one of the following structural formulas:
in the embodiment of the invention, the diol monomer containing polyester comprises at least one of the following structural formulas, wherein n is more than or equal to 4 and less than or equal to 80, x+y+z is more than or equal to 15 and less than or equal to 100, the polymerization degree is within the range, the molecular weight and crystallinity of the polyester chain segment are moderate, and the polyurethane can be ensured to have higher mechanical property, flexibility and bonding strength:
in an embodiment of the present invention, the polyether-containing diol monomer comprises at least one of the following structural formulas:
in the formula, n is more than or equal to 25 and less than or equal to 115, x+y+z is more than or equal to 19 and less than or equal to 90, the polymerization degree is within the range, the molecular weight and crystallinity of the polyether chain segment are moderate, and the polyurethane can be ensured to have higher mechanical property, flexibility and bonding strength.
In an embodiment of the present invention, the carboxyl group-containing diol monomer includes at least one of the following structural formulas:
in an embodiment of the present invention, the phosphate-containing diol monomer includes at least one of the following structural formulas:
in an embodiment of the invention, the diisocyanate monomer includes at least one of the following structural formulas:
in an embodiment of the invention, the polyol crosslinker comprises at least one of the following structural formulas:
the polyol used as the crosslinking agent is a polyol having a hydroxyl number of 3 or more in a straight chain or branched chain. The polyol crosslinking agent is further preferably triethanolamine and/or dihydromyricetin, and intramolecular or intermolecular hydrogen bonds are easily formed in the triethanolamine and the dihydromyricetin, so that the mechanical strength of the polyurethane adhesive and the bonding performance with a metal substrate are further improved.
In an embodiment of the invention, the catalyst comprises at least one of dibutyltin dilaurate, stannous octoate, bismuth neodecanoate.
In the embodiment of the invention, the hollow glass beads wrapped by the heat conducting filler have the diameter of 10-100 mu m. In the particle size range, the polyurethane adhesive can be stably and uniformly dispersed in a polyurethane matrix, does not generate sedimentation or agglomeration, and does not influence the mechanical property and the adhesive property of the polyurethane adhesive.
In the embodiment of the invention, in the hollow glass bead wrapped by the heat conducting filler, the ratio of the thickness of the wrapping of the heat conducting filler to the diameter of the hollow glass bead is (0.001-0.05): 1, the proper wrapping thickness is beneficial to exerting the heat conduction performance of the heat conduction filler to the maximum extent; the bulk density of the hollow glass beads is 0.1-0.9 g/cm 3 The hollow glass beads within the proper density range can promote the heat conducting filler to form more effective heat conducting passages in the polyurethane system, and can not gather at the interface of the polyurethane surface to influence the adhesive property of the polyurethane adhesive.
Conventional thermally conductive fillers for thermally conductive adhesives may be used in the present invention, including but not limited to at least one of boron nitride, molybdenum disulfide, aluminum oxide, aluminum nitride, silicon carbide, synthetic diamond.
In the embodiment of the invention, the hollow glass bead wrapped by the heat conducting filler is prepared by the following steps:
(1) Surface activation of hollow glass microspheres and thermally conductive fillers
Dispersing the hollow glass beads in an ethanol/water mixed solution, adding gamma-aminopropyl triethoxysilane (KH-550), stirring at 60-70 ℃ for reaction for 5-10h, and washing and drying by ethanol to obtain amino modified hollow glass beads;
dispersing the heat conducting filler in sodium hydroxide alkali liquor, and carrying out a reaction for 12-24 hours under the heating condition of 110-120 ℃ to activate the surface, and washing to obtain the hydroxyl activated heat conducting filler; dispersing the epoxy modified heat conducting filler in an ethanol/water mixed solution, adding 3-glycidoxypropyl trimethoxy silane (KH 560), stirring at 60-70 ℃ for reaction for 5-10h, and washing and drying by ethanol to obtain the epoxy modified heat conducting filler;
(2) Dispersing the amino modified hollow glass beads and the epoxy modified heat conducting filler in toluene organic solvent, stirring and reacting for 2-6 h at 100-120 ℃, and obtaining the hollow glass beads wrapped by the heat conducting filler through ring-opening addition reaction between amino and epoxy.
The invention also provides a preparation method of the recyclable polyurethane binder, which comprises the following steps:
and (3) according to the weight parts, carrying out a prepolymerization reaction on a polyurethane reaction monomer and a catalyst, then adding a polyol crosslinking agent for a crosslinking reaction, finally adding hollow glass beads wrapped by a heat conducting filler, uniformly mixing, and drying and curing to obtain the recyclable polyurethane binder.
In an embodiment of the present invention, the time of the pre-polymerization is 10 to 30 hours; the temperature of the prepolymerization is 60-80 ℃.
The use of the recyclable polyurethane binder in the preparation of batteries is also within the scope of the present invention.
Compared with the prior art, the invention has the beneficial effects that:
according to the invention, the reversible covalent bond is introduced into the polyurethane molecular chain segment to realize recycling of the polyurethane binder; the reversible covalent bond, the polyester or polyether chain segment and the carboxyl group are combined to improve the bonding performance of the polyurethane adhesive and the metal substrate; in addition, the introduction of the phosphate chain segment can not only improve the flame retardant property of polyurethane in a synergistic way with a specific reversible bond, but also can jointly act with the hollow glass bead wrapped by the special combined heat conducting filler, so that the heat resistance of the polyurethane is further improved, and the polyurethane adhesive can obtain higher heat conductivity under the condition of less addition of the heat conducting filler.
The polyurethane binder prepared by the invention has high heat conductivity, high flame retardance, high adhesion and recoverability, wherein: the heat conductivity is above 1W/mK and can reach 1.31W/mK; the flame retardance is above V0 grade; the bonding strength is above 8.8MPa at 60 ℃ and can reach 27.1MPa.
Detailed Description
For a better description of the objects, technical solutions and advantages of the present invention, the present invention will be further described with reference to the following specific examples, which are not intended to limit the present invention in any way. Unless specifically stated otherwise, the reagents, methods and apparatus employed in the present invention are those conventional in the art. The reagents and materials used in the present invention are commercially available unless otherwise specified.
Example 1
The embodiment provides a recyclable polyurethane binder, and the preparation method comprises the following steps:
melting and drying polyester or polyether glycol monomers, adding a solvent, diisocyanate monomers and a catalyst to react for 3-10 hours, then adding glycol monomers containing a hydrolyzable dynamic reversible bond, carboxyl glycol monomers and phosphate glycol monomers to react for 3-10 hours, then adding a polyol cross-linking agent to react for 3-10 hours, finally adding a heat conducting filler to stir uniformly, pouring, drying and solidifying to obtain the polyurethane, wherein the specific steps are as follows:
(1) 10g of polytetrahydrofuran glycol PTMEG2000 (number average molecular weight 2000, n=28) was charged into a 250mL three-necked flask under argon atmosphere, and after the temperature was raised to 120℃to melt PTMEG2000, the vessel was continuously vented for 2 hours to remove trace moisture in the reaction system;
(2) Then cooling to 80 ℃, adding 20mL of N, N-dimethylformamide, 7.9g of dicyclohexylmethane 4, 4-diisocyanate and 0.005g of catalyst dibutyltin dilaurate, continuing to react for 4 hours, cooling to 50 ℃ again, adding 3.62g of diol monomer 4,4' - (1, 4-phenylenebis (1, 3, 2-dioxaborane-2, 4-diyl)) bis (butan-1-ol) containing reversible covalent bond, reacting for 6 hours, and then slowly dropwise adding 0.67g of 2, 2-dimethylolpropionic acid and 3.33g of 6- ((bis (2-hydroxyethyl) amino) methyl) dibenzo [ c, e][1,2]After the reaction of the above system is continued for 6 hours, 0.1g of triethanolamine is used for crosslinking reaction for 6 hours, and finally 6.4g of hollow glass beads coated with boron nitride (the diameter is 80 mu m, the ratio of the thickness of the coating of the boron nitride to the radius of the hollow glass beads is 0.0375:1, and the bulk density of the hollow glass beads is 0.26 g/cm) 3 ) Stirring uniformly, pouring into a mould, and continuously curing for 16 hours at 60 ℃ to obtain the recyclable polyurethane binder.
Wherein, 4' - (1, 4-phenylene bis (1, 3, 2-dioxaborane-2, 4-diyl)) bis (butan-1-ol) is prepared according to the following method: dissolving terephthalic acid and pentanetriol containing 1,2, 5-in anhydrous tetrahydrofuran, adding anhydrous magnesium sulfate, stirring for 24 hr at 35 deg.C, filtering, rotary evaporating to remove solvent, and precipitating in n-hexane to obtain 4,4' - (1, 4-phenylene bis (1, 3, 2-dioxaborane-2, 4-diyl)) bis (butan-1-ol) with molecular structural formula of
The hollow glass bead wrapped by boron nitride is prepared by the following method:
(1) Dispersing the hollow glass beads in an ethanol/water mixed solution, adding gamma-aminopropyl triethoxysilane (KH-550), stirring at 70 ℃ for reaction for 10 hours, and washing and drying by ethanol to obtain amino modified hollow glass beads;
dispersing the heat conducting filler in sodium hydroxide alkali liquor, and carrying out a reaction for 12-24 hours under the heating condition of 110-120 ℃ to activate the surface, and washing to obtain the hydroxyl activated heat conducting filler; dispersing the epoxy modified heat conducting filler in an ethanol/water mixed solution, adding 3-glycidoxypropyl trimethoxy silane (KH 560), stirring at 60-70 ℃ for reaction for 5-10h, and washing and drying by ethanol to obtain the epoxy modified heat conducting filler;
(2) Dispersing the amino modified hollow glass beads and the epoxy modified heat conducting filler in toluene organic solvent, stirring and reacting for 6 hours at 120 ℃, and obtaining the hollow glass beads wrapped by the heat conducting filler through ring-opening addition reaction between the amino and the epoxy.
Example 2
This example provides a recyclable polyurethane binder prepared according to the method of example 1, differing from example 1 in that: in step (1), 10g of polytetrahydrofuran diol PTMEG2000 was replaced with an equimolar amount of polycaprolactone diol PCLD2000 (number average molecular weight 2000g/mol, x+y=19).
Example 3
This example provides a recyclable polyurethane binder prepared according to the method of example 1, differing from example 1 in that: in step (1), polytetrahydrofuran diol PTMEG2000 was replaced with an equimolar amount of polyethylene glycol PEG2000 (number average molecular weight 2000g/mol, n=45).
Example 4
This example provides a recyclable polyurethane binder prepared according to the method of example 1, differing from example 1 in that: in step (2), 7.9g of dicyclohexylmethane 4, 4-diisocyanate was replaced with an equimolar amount of isophorone diisocyanate monomer.
Example 5
This example provides a recyclable polyurethane binder prepared according to the method of example 1, differing from example 1 in that: in step (2), 7.9g of dicyclohexylmethane 4, 4-diisocyanate was replaced with an equimolar amount of hexamethylene diisocyanate.
Example 6
This example provides a recyclable polyurethane binder prepared according to the method of example 1, differing from example 1 in that: in step (2), 3.62g of 4,4'- (1, 4-phenylenebis (1, 3, 2-dioxaborane-2, 4-diyl)) bis (butan-1-ol) containing a borate linkage is replaced with an equimolar amount of N, N' - (1, 4-phenyldimethylethylene) -bis (2- (2-aminoethoxy) ethanol) containing an imine linkage;
wherein N, N' - (1, 4-phenyl dimethylethylene) -bis (2- (2-aminoethoxy) ethanol containing an imine bond is prepared as follows: dissolving terephthalaldehyde in toluene, cooling to 5 ℃ in ice water bath, slowly dropwise adding 2-amino ethanol into the solution, and refluxing the mixture until no water is formed in a water separator; the mixture was cooled to room temperature and then the precipitated product N, N' - (1, 4-phenyldimethylethylene) -bis (2- (2-aminoethoxy) ethanol) was collected by filtration, having the molecular structural formula:
example 7
This example provides a recyclable polyurethane binder prepared according to the method of example 1, differing from example 1 in that: in step (2), 3.62g of 4,4' - (1, 4-phenylenebis (1, 3, 2-dioxaborane-2, 4-diyl)) bis (butan-1-ol) containing a borate linkage was replaced with an equimolar amount of a mixture of 4,4' - (1, 4-phenylenebis (1, 3, 2-dioxaborane-2, 4-diyl)) bis (butan-1-ol) and N, N ' - (1, 4-phenyldimethylethylene) -bis (2- (2-aminoethoxy) ethanol) (molar ratio 1:1).
Example 8
This example provides a recyclable polyurethane binder prepared according to the method of example 1, differing from example 1 in that: in step (2), 0.67g of 2, 2-dimethylolpropionic acid was replaced with an equimolar amount of 2- (bis (2-hydroxyethyl) amino) propionic acid.
Example 9
This example provides a recyclable polyurethane binder prepared according to the method of example 1, differing from example 1 in that: in step (2), 3.33g of 6- ((bis (2-hydroxyethyl) amino) methyl) dibenzo [ c, e ] [1,2] oxaphosphorinane 6-oxide is replaced with an equimolar amount of 6- (2- (3, 4-dihydroxypiperidin-1-yl) ethyl) dibenzo [ c, e ] [1,2] oxaphosphorinane 6-oxide.
Example 10
This example provides a recyclable polyurethane binder prepared according to the method of example 1, differing from example 1 in that: in step (2), 0.1g of triethanolamine was replaced with an equimolar amount of dihydromyricetin.
Example 11
This example provides a recyclable polyurethane binder prepared according to the method of example 1, differing from example 1 in that: in the step (2), in the hollow glass beads coated with boron nitride, the ratio of the thickness of the boron nitride coating to the diameter of the hollow glass beads is 0.006:1, the other parameters remain unchanged.
Example 12
This example provides a recyclable polyurethane binder prepared according to the method of example 1, differing from example 1 in that: in the step (2), the diameter of the hollow glass microsphere wrapped by the boron nitride is 10 mu m, and other parameters are kept unchanged.
Example 13
This example provides a recyclable polyurethane binder prepared according to the method of example 1, differing from example 1 in that: in the step (2), the hollow glass beads are wrapped by boron nitride, and the bulk density of the hollow glass beads is 0.39g/cm 3 Other parameters remain unchanged.
Comparative example 1
This comparative example provides a polyurethane adhesive prepared according to the preparation method of example 1, which differs from example 1 in that: in step (2), 3.62g of 4,4' - (1, 4-phenylenebis (1, 3, 2-dioxaborane-2, 4-diyl)) bis (butan-1-ol) was replaced with an equimolar amount of butanediol, i.e., no reversible covalent bonds in the polyurethane binder matrix.
Comparative example 2
This comparative example provides a polyurethane adhesive prepared according to the preparation method of example 1, which differs from example 1 in that: 0.67g of 2, 2-dimethylolpropionic acid was replaced with an equimolar amount of butanediol, i.e.the polyurethane binder matrix contained no carboxyl groups.
Comparative example 3
This comparative example provides a polyurethane adhesive prepared according to the preparation method of example 1, which differs from example 1 in that: in step (2), 3.33g of 6- ((bis (2-hydroxyethyl) amino) methyl) dibenzo [ c, e ] [1,2] oxaphosphorinane 6-oxide is replaced with an equimolar amount of butanediol, i.e., the polyurethane binder matrix is free of phosphate groups.
Comparative example 4
This comparative example provides a polyurethane adhesive prepared according to the preparation method of example 1, which differs from example 1 in that: in the step (2), 6.4g of boron nitride-coated hollow glass beads are replaced by 6.4g of boron nitride.
Comparative example 5
This comparative example provides a polyurethane adhesive prepared according to the preparation method of example 1, which differs from example 1 in that: in step (2), 6.4g of the boron nitride-coated hollow glass beads were replaced with 3.1g of boron nitride and 3.3g of hollow glass beads.
Comparative example 6
This comparative example provides a polyurethane adhesive prepared according to the preparation method of example 1, which differs from example 1 in that: in the step (2), the adding amount of the hollow glass beads coated with boron nitride is 11g.
Comparative example 7
This comparative example provides a polyurethane adhesive prepared according to the preparation method of example 1, which differs from example 1 in that: in step (2), 6- ((bis (2-hydroxyethyl) amino) methyl) dibenzo [ c, e ] [1,2] oxaphosphorinane 6-oxide is replaced by an equimolar amount of 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-0-oxide without hydroxyl functional groups, and the hollow glass beads coated with boron nitride are added to the polymer matrix of the crosslinking reaction at the same time, namely, the monomer containing phosphate is not combined with polyurethane chain segments through covalent chemical bonds.
Performance testing
The properties of the polyurethane binders obtained in the above examples and comparative examples were characterized, and specific test items, test methods and results are as follows:
1. testing the tensile property of the polyurethane adhesive by adopting a tensile machine; the solution degradation recovery of the material was evaluated by gel chromatography (GPC): the polyurethane materials prepared in examples or comparative examples were immersed in an aqueous solution of 50 c and stirred for 120 hours with assistance, polymer degradation was observed, broken polymer chips were collected, and their molecular weights were tested to evaluate the effect of solution degradation, and the results are shown in table 1 below.
2. The thermal conductivity of the polyurethane adhesive is tested by adopting a Hot Disk method thermal conductivity tester; the UL-94 flame retardant rating of the polyurethane adhesive is analyzed by adopting a vertical burning test; the polyurethane adhesive was tested for lap bond strength to aluminum panels at-30, 25, and 60 ℃ using a tensile machine, and the results are shown in table 1 below.
Table 1 test results of polyurethane binders obtained in examples and comparative examples
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From the above results, it can be seen that:
the recyclable polyurethane binder prepared by the invention has high thermal conductivity, high flame retardance, high adhesiveness and recyclability, wherein: the heat conductivity is above 1W/mK and can reach 1.31W/mK; the flame retardance is above V-0 grade; the bonding strength is above 8.8MPa at 60 ℃ and can reach 27.1MPa. The polyurethane can be degraded to a certain extent through hydrolysis of built-in reversible bonds (borate bonds and imine bonds) after a period of water soaking and ultrasonic stirring treatment.
The adhesive before degradation is a polymer with a cross-linked structure, and cannot be dissolved in water, so that the molecular weight cannot be tested.
The results of comparative examples 1-3 are more excellent in tensile strength of polyurethane materials after PTMEG or PCLD addition than PEG; the results of comparative examples 1 and 4-5 are that rigid diisocyanates such as dicyclohexylmethane 4, 4-diisocyanate are more advantageous for reinforcing the tensile strength of materials than isophorone diisocyanate monomer or hexamethylene diisocyanate; as a result of comparative examples 1 and 2, since the polarity of the ester group is stronger than that of the ether group, the molecular chain of the polyester polyurethane is more polar than that of the polyether polyurethane, and the intermolecular interaction force is large, the inter-bond attraction force is higher, and thus the higher adhesive property is exhibited. As a result of comparative examples 1 and 7, there was a synergistic effect of the hydrolysis of the imine bond and the borate bond, and the molecular weight after degradation was reduced. As a result of comparative examples 1 and 10, the dihydromyricetin crosslinking agent can improve the tensile strength and elongation at break of the polyurethane material through hydrogen bond and pi-pi action, which is beneficial to further improving the bonding strength of the adhesive and is mainly attributed to the coordination effect of carbonyl groups of dihydromyricetin and residual phenolic hydroxyl groups after reaction and an aluminum substrate.
The polyurethane adhesive obtained in comparative example 1 does not contain reversible covalent bonds, cannot be degraded and recycled, and the flame retardant effect is correspondingly reduced because of no synergistic effect of specific reversible bonds and the phosphate flame retardant.
The comparative example 2 does not contain carboxyl groups, and the bonding strength and the combustion grade of the obtained adhesive with the base material are reduced, which shows that the introduction of the carboxyl group-containing dihydric alcohol monomer increases the content of polar groups in the adhesive, and can form coordination bonds with the aluminum base material, thereby improving the bonding performance on the aluminum base material, simultaneously being beneficial to increasing the degradation degree in aqueous solution, and promoting the dehydration of the material to improve the flame retardant effect when the base material is combusted.
The performance test results of example 1 and comparative example 3 show that the diol monomer containing the phosphate structure can be used as a reactive flame retardant to improve the flame retardant effect.
As can be seen from the performance test results of example 1 and comparative examples 4 to 6, increasing the amount of the heat conductive filler can improve the heat conductivity, but the excessive filler is disadvantageous for the tensile strength and the adhesive strength; meanwhile, compared with the common boron nitride, the hollow glass microsphere wrapped by the boron nitride with the same content can obtain better heat conduction effect, which indicates that the method of utilizing the space limitation is beneficial to constructing a heat conduction path and reducing the filling quantity.
Comparison of the results of example 1 with comparative example 7 further shows that covalent bonding of the phosphate segment to the polyurethane segment is advantageous in improving the rigidity of the polyurethane chain and crystallization of the hard block, thereby improving the heat resistance of the polyurethane adhesive and avoiding the decay of the adhesive's adhesive properties at high temperatures, as compared to direct blending dispersion.
Finally, it should be noted that the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the scope of the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present invention may be modified or substituted equally without departing from the spirit and scope of the technical solution of the present invention.

Claims (10)

1. The recyclable polyurethane binder is characterized by comprising the following components in parts by weight:
2. the recyclable polyurethane binder of claim 1 wherein the reversible covalent bonds in the diol monomers are borate and/or imine bonds;
when the reversible covalent bond is a borate ester bond, the diol monomer containing the reversible covalent bond includes at least one of the following structural formulas:
when the reversible covalent bond is an imine bond, the diol monomer containing the reversible covalent bond includes at least one of the following structural formulas:
3. the recyclable polyurethane binder of claim 1 wherein, in the polyester or polyether containing glycol monomer:
the polyester-containing diol monomer comprises at least one of the following structural formulas, wherein n is more than or equal to 4 and less than or equal to 80, and x+y+z is more than or equal to 15 and less than or equal to 100:
the diol monomer containing polyether comprises at least one of the following structural formulas, wherein n is more than or equal to 25 and less than or equal to 115, and x+y+z is more than or equal to 19 and less than or equal to 90:
4. the recyclable polyurethane binder of claim 1 wherein the carboxyl group containing diol monomer comprises at least one of the following structural formulas:
5. the recyclable polyurethane binder of claim 1 wherein the phosphate ester-containing glycol monomer comprises at least one of the following structural formulas:
6. the recyclable polyurethane binder of claim 1 wherein the diisocyanate monomer comprises at least one of the following structural formulas:
7. the recyclable polyurethane binder of claim 1 wherein the polyol crosslinking agent comprises at least one of the following structural formulas:
8. the recyclable polyurethane binder of claim 1 wherein the thermally conductive filler-encased hollow glass microspheres satisfy at least one of the following characteristics:
1) The heat conducting filler comprises at least one of boron nitride, molybdenum disulfide, aluminum oxide, aluminum nitride, silicon carbide and artificial diamond;
2) The diameter of the hollow glass bead wrapped by the heat conducting filler is 10-100 mu m;
3) The ratio of the thickness of the heat conducting filler package to the diameter of the hollow glass beads is (0.001-0.05): 1, a step of;
4) The bulk density of the hollow glass beads is 0.1-0.9 g/cm 3 。
9. The method for producing a recyclable polyurethane adhesive according to any one of claims 1 to 8, comprising the steps of:
and (3) according to the weight parts, carrying out a prepolymerization reaction on a polyurethane reaction monomer and a catalyst, then adding a polyol crosslinking agent for a crosslinking reaction, finally adding hollow glass beads wrapped by a heat conducting filler, uniformly mixing, and drying and curing to obtain the recyclable polyurethane binder.
10. Use of a recyclable polyurethane binder as claimed in any one of claims 1 to 8 in the manufacture of a battery.
CN202310622924.4A 2023-05-30 2023-05-30 Recyclable polyurethane binder and preparation method and application thereof Pending CN116875258A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117866168A (en) * 2024-03-11 2024-04-12 广东工业大学 Bio-based self-repairing type high-strength high-toughness polyurethane material and preparation method thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117866168A (en) * 2024-03-11 2024-04-12 广东工业大学 Bio-based self-repairing type high-strength high-toughness polyurethane material and preparation method thereof
CN117866168B (en) * 2024-03-11 2024-05-07 广东工业大学 Bio-based self-repairing type high-strength high-toughness polyurethane material and preparation method thereof

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