Precipitation-free lubricant and preparation method thereof

Abstract

The invention discloses a precipitation-free lubricant and a preparation method thereof.According to the lubricant, a high-molecular-weight temperature-sensitive long-chain main chain containing a reversible covalent bond is grafted with a short-chain side chain containing a lubricating functional group, the long-chain main chain is Diels-Alder bond grafted polyolefin, acetal bond grafted perfluoropolyether or thioester bond grafted polysiloxane, and the long-chain main chain is a long-chain side chain or a short-chain side chain containing a lubricating functional group. The short-chain side chain is a thiol-siloxane composite short chain, a fluorocarbon-siloxane composite short chain or fatty acid amide, and the long-chain main chain is connected with the short-chain side chain through a carbon-carbon bond or a fluorocarbon chain segment. A high-molecular-weight main chain containing reversible covalent bonds is broken into a low-molecular-weight short-chain side chain with a lubricating function at a resin curing temperature, so that the high-temperature viscosity of the resin composite material is reduced, the flowability of a system is remarkably improved, the lubricating capacity is enhanced, reversible recombination is realized during cooling, a long-chain network is formed, a lubricant is prevented from being separated out, and the mechanical capacity of the resin is enhanced; the method is suitable for high-performance resin processing scenes of precision electronic packaging, aviation composite materials and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer processing aids, and particularly relates to a non-precipitating lubricant and a preparation method thereof. Background Art

[0002] Resin processing lubricants can improve the fluidity of polymers during molding. Usually, the viscosity of resin melt is very high. During molding, the melt must enter the mold cavity from the nozzle, gate, and runner within a short time. In order to enable the melt to smoothly fill the mold cavity, it is crucial to reduce the viscosity of the melt and improve the fluidity of the melt. Therefore, lubricants need to be added. In addition, lubricants can also promote melting, facilitate demolding, prevent static electricity, prevent adhesion, etc.

[0003] Among them, internal lubricants have good compatibility with polymers. They play a role in reducing the internal cohesion between polymer molecules inside the polymer, thereby improving the internal friction heat generation and melt fluidity of plastic melts. Typical examples in the prior art are as follows:

[0004] CN 104177744 B discloses an anti-precipitation lubricant. The material is measured by weight parts of components: 10 - 20 parts of aromatic carboxylate, 2 - 8 parts of calcium stearate, and 2 - 5 parts of dispersant. The anti-precipitation lubricant prepared by the present invention is a white powder with small particle size and a melting point above 300°C, and can remain solid during the entire high-temperature processing process; and the preparation process is simple, the operation is convenient, and the performance is stable, effectively solving the problem of lubricant precipitation, and having good lubrication effect and economic benefits.

[0005] CN 110003523 A provides a polyester lubricant and a preparation method thereof. Under the protection of a protective gas, stearic acid, pentaerythritol, an activator, and an antioxidant are added to a reaction vessel and heated to melt. The present invention utilizes highly efficient activators and promoters to improve the reaction efficiency and degree of acids and alcohols in the system, thereby improving the thermal stability of the product polyester lubricant. Compared with the polyester wax prepared by traditional processes, the product prepared by the present invention has the characteristics of high whiteness, low color value, few by-products, high purity, and excellent yellowing resistance and precipitation resistance during use.

[0006] CN118109005A discloses an anti-precipitation lubricant for PVC. By using glycidyl methacrylate grafted PE wax as a lubricant, the problem of poor compatibility between traditional PE wax and the PVC system containing calcium-zinc stabilizers is improved, thereby inhibiting the precipitation of PE wax.

[0007] CN 110358608 A uses the blend modification of fluorocarbon resin and chlorinated ether resin, and introduces chlorinated polyether to reduce the interfacial tension between the two and improve the strength of the lubricant.

[0008] CN 111217973 B discloses a polyurethane lubricant, its preparation method and uses. This lubricant is prepared by reacting a diisocyanate with an aliphatic compound containing a monofunctional active hydrogen group. This lubricant features excellent compatibility with thermoplastic polyurethane, no exudation, outstanding anti-sticking and lubricating effects.

[0009] CN 118931087 B relates to a mass fraction ratio of raw material components of a lubricant, including: 20 - 28 parts of methyl methacrylate grafted polypropylene wax, 32 - 40 parts of MBS resin powder, 8 - 16 parts of chlorinated paraffin, 16 - 22 parts of TPP (tricresyl phosphate), 4 - 10 parts of zinc borate, and 2 - 8 parts of silicone powder.

[0010] Based on the above-mentioned prior art and statistics of lubricants on the market, most of them are basic stearates, low-melting-point polymers, low-boiling-point oils and / or maleic anhydride grafted polymers. Basic stearates are prone to destroying acidic additives in the board and are also likely to react with acidic maleic anhydride grafted polymers, resulting in limited improvement in compatibility and thus defects in the performance of the board. Low-melting-point polymers and low-boiling-point oils are likely to exude from the board, are prone to loss during the hot melt processing, and there will also be quality problems and environmental protection problems caused by exudation during daily use.

[0011] Due to the disadvantages of low-molecular-weight materials or inorganic materials, the prior art has developed a design method of long-chain main chains plus functional side chains, such as:

[0012] CN 118994893 A includes the following raw material components by weight: 10 - 20 parts of epoxidized amide and 15 - 40 parts of ammoniated silicone oil. After preparing a long-chain fatty acid amide, it is epoxidized, chain-extended, acidified, imidized, and secondarily epoxidized to obtain epoxidized amide. After fluorinating p-methyl high-hydrogen silicone oil and then telomerizing with siloxane organic compounds and nitriding, ammoniated silicone oil is obtained. Finally, a green and efficient lubricant is obtained through mixing, and at the same time, the mechanical properties and wear resistance of polyvinyl chloride resin can be improved.

[0013] CN 115160644 B provides a nucleating lubricant, its preparation method and application. The preparation raw materials of the nucleating lubricant include a combination of hydrazine hydrate, formic acid, and a fatty acid with a carbon chain length of not less than 10. The structure of the nucleating lubricant prepared from the above three raw materials has both a long carbon chain and a strongly polar bisamide group, thereby making it have both excellent self-lubricity and anti-exudation properties, which can increase the crystallization rate of polyurethane resin and shorten the demolding time of polyurethane resin; and the nucleating lubricant also has good compatibility with polyurethane resin, which helps to improve the transparency of polyurethane products.

[0014] CN 110218400 A. In the present invention, due to the flexibility and thermal stability of the high molecular chain of silicone oil, it can be quickly and uniformly dispersed in the molten plastic fluid. The high molecular structure composed of the silicon-oxygen bond main chain and the organic group side chain is similar to the carbon-carbon chain polymer component. The prepared PVC composite lubricant can promote the dispersion of fillers and then play roles such as lubrication and reinforcement.

[0015] CN116041786B discloses a composite EBS lubricant resistant to precipitation during the processing process. By in-situ reaction, a substance of ethylene bis-fatty acid amide with a long-chain structure is mixed into EBS. The main effect of this technology is to reduce the precipitation of EBS in the molten state of the polymer by partially replacing EBS.

[0016] CN 109467852 A. The present invention discloses an internal lubricant prepared by stepwise reaction of polyol, polyacid and long-chain fatty alcohol through a specific process. By applying the internal lubricant prepared by the present invention, it is found that it can accelerate plasticization during the PVC processing process and has a strong internal lubrication function. Moreover, there is no precipitation during and after the use in the PVC processing process, and the refractive index is also close to that of PVC, making the PVC products have good transparency and gloss.

[0017] In the above patents, lubricity is provided by long-chain carbon chains (C≥10), and the friction coefficient is reduced by using the low surface energy characteristics (such as EBS derivatives, silicone oil side chains, amide groups). The long chains form a physical isolation layer in the resin matrix, reducing the intermolecular force and promoting the processing fluidity. Through the design of introducing polar groups: by introducing amide (CN 115160644 B), ester bond (CN109467852 A), epoxy group (CN 118994893 A) or siloxane structure (CN 110218400 A), the compatibility with polar resins (such as PVC, polyurethane) is improved and precipitation is inhibited. However, due to the presence of fat and silane coupling agent in the above lubricants, there are still side reactions with curing agents, catalysts or resin matrices (such as ester bond hydrolysis, silane group crosslinking), resulting in the failure of the lubrication function or the decline of the mechanical properties of the resin. At the same time, there are generally defects such as complex processes, high costs, great environmental protection pressure and single functions. The future improvement direction needs to focus on the development of green processes, the substitution of low-cost raw materials, multifunctional design, and the improvement of biodegradability to meet the dual requirements of high-end manufacturing for environmentally friendly and high-performance lubricants. Summary of the Invention

[0018] In view of the related problems, the present invention provides a non-precipitating lubricant and its preparation method.

[0019] The present invention solves the problems existing in the prior art by using the following technical solutions: providing a non-bleeding lubricant, which includes a high-molecular-weight thermosensitive long-chain main chain containing reversible covalent bonds, and grafts short-chain side chains containing lubricating functional groups through carbon-carbon bonds or fluorocarbon chain segments. At the resin curing temperature, the reversible covalent bonds of the thermosensitive main chain dissociate, and the main chain breaks into low-molecular-weight fragments (Mn≤2000), thereby improving the dispersion of the short-chain side chains in the resin. After cooling, the covalent bonds are reversibly recombined, inhibiting the migration and bleeding of the lubricant, realizing the dynamic regulation of "thermosensitive fracture-cooling recombination", and at the same time improving the environmental protection problem of the material.

[0020] The specific invention content is as follows:

[0021] A non-bleeding lubricant includes a long-chain main chain containing reversible covalent bonds and short-chain side chains containing lubricating functional groups, and the long-chain main chain and the short-chain side chains are grafted through carbon-carbon bonds or fluorocarbon chain segments.

[0022] Preferably, the long-chain main chain is one of a Diels-Alder bond-grafted polyolefin chain, an acetal bond-grafted perfluoropolyether chain, or a thioester bond-grafted polysiloxane chain.

[0023] Preferably, the short-chain side chain is one of a thiol-siloxane composite short chain, a fluorocarbon-siloxane composite short chain, or a fatty acid amide.

[0024] Preferably, the thermosensitive response range of the non-bleeding lubricant is 100-200°C.

[0025] Preferably, when the long-chain main chain is a Diels-Alder bond-grafted polyolefin chain or an acetal bond-grafted perfluoropolyether chain, the non-bleeding lubricant is applicable to polar resins.

[0026] Preferably, when the long-chain main chain is an acetal bond-grafted perfluoropolyether chain or a thioester bond-grafted polysiloxane chain, the non-bleeding lubricant is applicable to non-polar resins.

[0027] Preferably, the number-average molecular weight Mn of the Diels-Alder bond-grafted polyolefin chain is 5000-20000, and the fracture temperature is 120-180°C.

[0028] More preferably, the number-average molecular weight Mn of the Diels-Alder bond-grafted polyolefin chain is 8000-15000.

[0029] More preferably, the main chain polyolefin functional group of the Diels-Alder bond-grafted polyolefin chain is derived from one of polyethylene, polypropylene, and poly-α-olefin, the graft monomer of the Diels-Alder bond-grafted polyolefin chain is one of maleic anhydride, fumarate, and glycidyl acrylate, and the diene functional group of the Diels-Alder bond-grafted polyolefin chain comes from one of furan, furfuryl alcohol, furfuryl methanol, difuran, and furanpropionic acid in furan compounds.

[0030] Preferably, the number average molecular weight Mn of the acetal bond-grafted perfluoropolyether chain is 5000 - 15000, and the fracture temperature is 150 - 200 °C.

[0031] More preferably, the number average molecular weight Mn of the acetal bond-grafted perfluoropolyether chain is 8000 - 15000.

[0032] More preferably, the main chain of the acetal bond-grafted perfluoropolyether chain is perfluoropolyether, and the side chain functional group is derived from one or several of polyethylene glycol, allyl acetal, diallyl acetal, and perfluoroalkyl acetal.

[0033] Preferably, the number average molecular weight Mn of the thioester bond-grafted polysiloxane chain is 3000 - 10000, and the fracture temperature is 100 - 160 °C.

[0034] More preferably, the number average molecular weight Mn of the thioester bond-grafted polysiloxane chain is 3000 - 8000.

[0035] More preferably, the main chain of the thioester bond-grafted polysiloxane chain is one of PDMS or methyl / phenyl modified siloxane and vinyl-terminated polydimethylsiloxane, and the side chain functional group is derived from one of mercaptopropyltriethoxysilane, bis(mercaptopropyl)tetramethyldisiloxane, and mercaptoacetic acid modified siloxane.

[0036] Preferably, the chain length of the main chain siloxane segment of the thiol-siloxane composite short chain is C2 - C4.

[0037] More preferably, the siloxane segment is derived from one or several of dimethyldisiloxane, trimethyltrisiloxane, and tetramethyltetrasiloxane.

[0038] More preferably, the source of the thiol functional group is one of n-octyl mercaptan, dodecyl mercaptan, mercaptoacetic acid, and 3-mercaptopropyltriethoxysilane.

[0039] Preferably, the chain length of the main chain fluorocarbon segment of the fluorocarbon-siloxane composite short chain is C6 - C7.

[0040] More preferably, the main chain of the fluorocarbon segment is derived from one or more of perfluorohexylethyl mercaptan, perfluorohexylethoxy mercaptan, perfluorohexylsulfonamide methyl mercaptan, perfluoroheptylethyl mercaptan, perfluoroheptylethoxy mercaptan, and perfluoroheptylsulfonamide mercaptan.

[0041] More preferably, the source of the siloxane functional group is one of allyl siloxane, trimethyltrisiloxane, and tetramethyltetrasiloxane.

[0042] Preferably, the chain length of the fatty acid amide segment is C18 - C20.

[0043] More preferably, the fatty acid amide is one or more of erucic acid amide, stearic acid amide, stearic acid piperazine amide, and oleic acid amide.

[0044] A preparation method of a non - precipitating lubricant includes the following steps:

[0045] S1: Synthesis of a long - chain main chain containing reversible covalent bonds. Under inert gas protection, take a functional polymer main chain precursor as one of polyolefin, perfluoropolyether, and polysiloxane, add the corresponding amount of reversible covalent bond grafting monomer, dissolve it in a solvent, add an initiator or catalyst, heat and react at high temperature, and perform post - treatment after cooling to obtain a long - chain main chain containing reversible covalent bonds;

[0046] S2: Synthesis of a short - chain side chain with lubricating function. Take a lubricating group containing an unsaturated bond and a compound containing active hydrogen to carry out a thiol - ene click reaction or an enzyme - catalyzed amidation reaction, add a photo / radical initiator, and initiate the reaction by ultraviolet light or heat. After the reaction, remove the solvent by vacuum distillation to obtain a short - chain side chain containing a lubricating functional group;

[0047] S3: Side - chain grafting and passivation. Mix the long - chain main chain and the short - chain side chain in a molar ratio of 1:2 - 6, add a radical initiator or a metal catalytic system, carry out a photothermal reaction or a catalytic reaction, after the reaction, precipitate with a selective solvent, then filter and dry in vacuum to obtain a non - precipitating lubricant.

[0048] Preferably, when the long - chain main chain is synthesized by the Diels - Alder reaction, the short - chain side chain is a thiol - siloxane composite short chain. Its specific preparation method includes the following steps:

[0049] S1: Construct the main chain containing reversible bonds through the Diels-Alder reaction. Under nitrogen protection, dissolve 1 - 1.5 mmol of graft monomer-modified polyolefin and 1 - 1.5 mmol of furan compound in 50 - 60 ml of solvent SA1, add 0.1 - 0.3 mol% of catalyst SA1, heat the reaction in an oil bath at 110 - 120 °C for 6 - 8 hours, after cooling, precipitate, filter, and dry in vacuo at 60 - 70 °C for 10 - 12 hours to obtain the long-chain main chain with Diels-Alder bond-grafted polyolefin chains;

[0050] S2: Synthesize the lubricating side chain containing terminal non-reactive groups by thiol-ene click reaction or radical polymerization. Under ultraviolet light irradiation at 365 - 375 nm, mix 5 - 7 mmol of siloxane segment and 5 - 7 mmol of thiol compound in 20 - 30 ml of solvent SB1, add 0.5 - 0.8 mol% of photoinitiator SB1, react for 30 minutes, remove the solvent by vacuum distillation to obtain the short-chain side chain with thiol-siloxane composite;

[0051] S3: Graft the side chain to the long-chain main chain through a carbon-carbon bond under the action of a catalyst. Mix 1 - 1.5 mmol of long-chain main chain and 5 - 7 mmol of short-chain side chain in 30 - 40 mL of solvent SC1, add 0.2 - 0.4 mol% of catalyst SC1, react at 80 °C for 4 hours to complete the carbon-carbon bond grafting. Precipitate the reaction solution with acetone or water with a volume ratio of 3:1, filter, and dry in vacuo at 60 °C for 12 hours to obtain the non-precipitating lubricant.

[0052] More preferably, the solvent SA1 is one of toluene, xylene, chloroform, THF, and DMF.

[0053] More preferably, the catalyst SA1 is one of p-toluenesulfonic acid (PTSA), camphorsulfonic acid (CSA), and [HSO3-Bmim]HSO4.

[0054] More preferably, the thiol compound is one of n-octanethiol, dodecyl mercaptan, mercaptoacetic acid, and 3-mercaptopropyltriethoxysilane.

[0055] More preferably, the solvent SB1 is one of acetonitrile, n-hexane, isopropanol, and tert-butanol.

[0056] More preferably, the photoinitiator SB1 is one of riboflavin, benzophenone, Irgacure2959, TPO, and BAPO.

[0057] More preferably, the solvent SC1 is one of toluene, xylene, THF, DMF, and NMP.

[0058] More preferably, the catalyst SC1 is one of RuCl3, Grubbs I generation, and Grubbs II generation.

[0059] More preferably, the high-temperature fracture of the Diels-Alder bond of the non-precipitating lubricant releases the side chain, and after cooling, it recombines to restore high molecular weight, which is suitable for polar resins.

[0060] Preferably, when the long-chain main chain is prepared by grafting a perfluoropolyether main chain through an acetal reaction, the short-chain side chain adopts a fluorocarbon-siloxane composite short chain. The specific preparation method includes the following steps:

[0061] S1: Construct a main chain containing a reversible bond through an acetal reaction. Under nitrogen protection, 2 - 3 mmol of perfluoropolyether and 1.5 - 2 mmol of acetal-functional monomer are mixed in 50 - 60 ml of solvent SA2, 0.5 - 0.7 mol% of acidic ionic liquid catalyst SA2 is added, and the reaction is heated in an oil bath at 150 - 160 °C for 8 - 10 hours. After cooling, the reaction solution is neutralized with NaHCO3, the organic phase is taken by layering, and the solvent is removed by vacuum distillation to obtain a long-chain main chain with an acetal bond grafted perfluoropolyether main chain;

[0062] S2: Synthesize a lubricating side chain containing a terminal inactive group by a thiol-ene click reaction. Under ultraviolet light irradiation at 365 - 375 nm, 5 - 7 mmol of fluorocarbon chain segments and 5 - 7 mmol of siloxane chain segments SB2 are mixed in 50 - 60 ml of solvent, 1 - 2 mol% of photoinitiator is added, and the reaction is carried out for 2 hours. The solvent is removed by vacuum distillation to obtain a short-chain main chain of a fluorocarbon-siloxane composite side chain.

[0063] S3: Under the action of a radical initiator, graft the side chain to the thermosensitive main chain through a carbon-carbon bond. 2 - 3 mmol of the long-chain main chain and 5 - 6 mmol are mixed in 30 - 40 ml of solvent, 2 - 3 mol% of thermal initiator is added, and the radical grafting is completed by reacting at 80 - 85 °C for 6 hours under nitrogen protection. The reaction solution is precipitated with an ethanol and water solution with a volume ratio of 2:1, filtered, and vacuum dried at 70 °C for 12 hours to obtain a non-precipitating lubricant.

[0064] More preferably, the perfluoropolyether is one of Krytox 157, Fomblin Y series, and Demnum SA / MS series.

[0065] More preferably, the solvent SA2 is one of toluene, xylene, chloroform, THF, and DMF.

[0066] More preferably, the catalyst SA2 is one of [HSO3-Bmim]HSO4, sodium bisulfate, camphorsulfonic acid (CSA), and nano solid acid.

[0067] More preferably, the siloxane SB2 is one of allyl siloxane, trimethyltrisiloxane, and tetramethyltetrasiloxane.

[0068] More preferably, the solvent SB2 is one of acetonitrile, n-hexane, isopropyl alcohol, and tert-butanol.

[0069] More preferably, the photoinitiator SB2 is one of benzophenone, Irgacure 2959, TPO, BAPO, and riboflavin.

[0070] More preferably, the solvent SC2 is one of toluene, xylene, THF, DMF, NMP, and dichloromethane.

[0071] More preferably, the thermal initiator SC2 is one of IBN, BPO, V50, VA-044, and V65.

[0072] More preferably, the acetal bond of the non-precipitating lubricant breaks under high-temperature acidic conditions and recombines after cooling, and it is suitable for polar and non-polar resins.

[0073] Preferably, when the long-chain main chain is prepared by grafting a polysiloxane main chain through a thioester bond reaction, the specific preparation method includes the following steps:

[0074] S1: Construct a main chain containing a reversible bond through a thioester bond reaction. Under nitrogen protection, 2 - 3 mmol of modified polysiloxane and 2 - 3 mmol of mercapto-modified siloxane are mixed in 40 - 50 ml of solvent SA3, 1 - 2 mol% of thermal initiator SA3 is added, and the mixture is heated in an oil bath at 60 - 70 °C for 5 - 6 hours. The solvent is removed by vacuum distillation to obtain the long-chain main chain of thioester bond-grafted polysiloxane.

[0075] S2: Synthesize a lubricating side chain by an enzyme-catalyzed amidation reaction. 10 - 12 mmol of fatty acid substrate and 5 - 6 mmol of amine compound are mixed in 30 - 40 ml of solvent SB3, 5 - 6 wt% of lipase catalyst SB3 is added, and the reaction is carried out at 70 - 80 °C for 10 - 12 hours. The enzyme catalyst is removed by filtration, and the short-chain side chain of erucic acid amide is obtained by vacuum distillation.

[0076] S3: Under the action of an atom transfer radical polymerization catalytic system, graft the side chain to the long-chain main chain through a carbon-carbon bond. Under nitrogen protection, 2 - 3 mmol of long-chain main chain and 5 - 6 mmol of short-chain side chain are mixed in solvent SC3, 1 - 2 mol% of metal catalyst SC3 and 0.5 - 1 mol% of ligand are added, and the atom transfer radical polymerization grafting is completed by reacting at 90 - 95 °C for 8 - 9 hours. The reaction solution is precipitated with ether or water with a volume ratio of 5:1, and after filtration, it is vacuum dried at 60 °C for 12 hours to obtain a non-precipitating lubricant.

[0077] More preferably, the solvent SA3 is one of THF, DMF, chloroform, toluene, and acetonitrile.

[0078] More preferably, the thermal initiator SA3 is one of AIBN, BPO, V50, VA-044, and V65.

[0079] More preferably, the fatty acid substrate is one of erucic acid (C18 unsaturated), stearic acid (C18 saturated), oleic acid (C18), and palmitic acid (C16).

[0080] More preferably, the amine compound is one of ethylenediamine, hexamethylenediamine, piperazine, and ethanolamine.

[0081] More preferably, the solvent SB3 is one of n-hexane, cyclohexane, tert-butanol, and isooctane.

[0082] More preferably, the catalyst SB3 is one of Novozym 435 (CALB), Lipozyme TL IM, Lipase PS, and Lipase Amano.

[0083] More preferably, the solvent SC3 is one of DMF, THF, NMP, DMAc, and DMSO.

[0084] More preferably, the metal catalyst SC3 is one of CuBr, CuCl, and FeCl2.

[0085] More preferably, the ligand is one of PMDETA, bpy, TPEN, and Me6-TREN.

[0086] More preferably, the thioester bond of the non-precipitating lubricant breaks under thermal or light stimulation, with high recombination efficiency and being suitable for non-polar resins.

[0087] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0088] (1) Thermosensitive fracture characteristics. The main chain breaks at the resin curing temperature (120 - 200 °C), releasing the side-chain lubricating units, and the viscosity of the system decreases by 40% - 60%; after cooling, the main chain recombines, and the lubricant returns to the high molecular weight state, with the migration rate reduced by more than 90%.

[0089] (2) Chemical inertness. The side chains are fixed by carbon-carbon bonds or fluorocarbon chain segments, avoiding reaction with the resin curing agent or catalyst (the change rate of gel time ≤ 5%).

[0090] (3) Mechanical property retention. After curing, the main chain of the lubricant recombines into a high molecular network, forming physical entanglement with the resin matrix, and the tensile strength retention rate ≥ 95% (compared with the unmodified sample). Brief Description of the Drawings

[0091] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0092] Figure 1 It is the process route diagram of the present invention. Detailed Description of the Embodiments

[0093] The endpoints and any values disclosed in the scope of the present invention are not limited to the exact scope or value. These scopes or values should be understood to include values close to these scopes or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in the present invention.

[0094] Example 1: Diels - Alder Bond - Grafted Polyolefin Main Chain + Siloxane Side Chain

[0095] S1: Synthesis of Thermosensitive Long - Chain Main Chain (Construction of DA Bond)

[0096] Under nitrogen protection, 2 mmol of maleic anhydride - grafted polyethylene with Mn = 10000 and 1 mmol of furan were dissolved in 55 ml of toluene, 0.2 mol% of p - toluenesulfonic acid was added as a catalyst, and the reaction was heated in an oil bath at 120 °C for 6 hours. After cooling, it was precipitated with ether and filtered, and then vacuum - dried at 60 °C for 12 hours to obtain a Diels - Alder bond - grafted polyolefin long - chain main chain.

[0097] S2: Synthesis of Side Chains of Lubricating Functional Groups (Thiol - Ene Click Reaction)

[0098] Under ultraviolet light irradiation with a wavelength of 365 nm, 6 mmol of allyltrimethylsiloxane and 6 mmol of n - octyl mercaptan were mixed in 25 ml of acetonitrile, 0.6 mol% of riboflavin was added as a photoinitiator, and the reaction was carried out at room temperature for 30 minutes. The solvent was removed by reduced - pressure distillation to obtain a thiol - siloxane composite short - chain side chain containing terminal inactive groups.

[0099] S3: Grafting of Side Chains to the Main Chain (Grubbs Catalysis)

[0100] Mix 3 mmol of long-chain main chain with 6 mmol of short-chain side chain in 40 ml of toluene, add 0.4 mol% of Grubbs second-generation catalyst, and react at 80 °C for 4 hours to complete the carbon-carbon bond grafting. The reaction solution is precipitated with an acetone / water solution with a volume ratio of 3:1, filtered, and vacuum dried at 60 °C for 12 hours to obtain a non-precipitating lubricant.

[0101] For the preparation of resin samples from the non-precipitating lubricant prepared in Example 1, the specific operation steps are as follows:

[0102] Take 100 parts of bisphenol A epoxy resin (E-51, epoxy value 0.51) as the matrix resin, 12 parts of tetraethylenepentamine (TEPA) as the curing agent, 1.5 parts of lubricant, melt and mix premix at 120 °C for 5 minutes, pre-cure in a sample preparation mold at 80 °C for 1 hour, and post-cure at 150 °C for 2 hours.

[0103] Performance testing:

[0104] (1) DSC detection shows that the DA bond breaking temperature is 150 °C;

[0105] (2) GPC analysis shows that Mn decreases from 12000 to 1800 after the main chain breaks;

[0106] (3) Rheological testing shows that the viscosity of the epoxy resin system decreases by 62%;

[0107] (4) The precipitation rate ≤ 0.3%, and the tensile strength retention rate ≥ 97%;

[0108] (5) Suitable for the processing of precision electronic packaging materials.

[0109] Example 2: Acetal bond grafted perfluoropolyether main chain + fluorocarbon-siloxane composite side chain

[0110] S1: Synthesis of temperature-sensitive long-chain main chain (construction of acetal bond)

[0111] Under nitrogen protection, dissolve 3 mmol of perfluoropolyether (Krytox 157, Mn = 8000) and 2 mmol of glutaraldehyde diethyl acetal in 60 ml of toluene, add 0.7 mol% of [HSO3-Bmim]HSO4 acidic ionic liquid as a catalyst, heat and react in an oil bath at 150 °C for 10 hours, cool, neutralize the reaction solution with NaHCO3, separate the organic phase by layering, and remove the solvent by vacuum distillation to obtain an acetal bond grafted perfluoropolyether long-chain main chain.

[0112] S2: Synthesis of short-chain side chain of lubricating functional group (thiol-ene click reaction)

[0113] Under ultraviolet light irradiation with a wavelength of 365 nm, 7 mmol of perfluorohexylethyl mercaptan was mixed with 6 mmol of trimethyltrisiloxane in 55 ml of acetonitrile, and 1.5 mol% of benzophenone was added as a photoinitiator. The reaction was carried out at room temperature for 2 hours, and the solvent was removed by distillation under reduced pressure to obtain a fluorocarbon-siloxane composite short-chain side chain.

[0114] S3: Side chain grafted to the main chain (free radical polymerization)

[0115] 2.5 mmol of the long-chain main chain was mixed with 5 mmol of the short-chain side chain in 30 ml of xylene, and 3 mol% of AIBN thermal initiator was added. The free radical grafting was completed by reacting at 80 °C for 6 hours under nitrogen protection. The reaction solution was selectively precipitated with an ethanol / water solution with a volume ratio of 2:1, filtered, and vacuum dried at 70 °C for 12 hours to obtain a non-precipitating lubricant.

[0116] For the preparation of the resin sample of the non-precipitating lubricant prepared in Example 2, the specific operation steps are as follows:

[0117] Take 100 parts of thermosetting polyimide (PMR-15, prepolymer molecular weight 1500), 2 parts of lubricant, pre-disperse in NMP solvent, ultrasonically treat for 30 minutes, and cure by gradient heating under nitrogen protection. The curing conditions are 120 °C / 1 h, 200 °C / 2 h, and 250 °C / 3 h.

[0118] Performance test:

[0119] (1) The acetal bond cleavage temperature is 180 °C;

[0120] (2) After high-temperature heating, the resin viscosity decreased by 45%, and the tensile strength retention rate was 95%;

[0121] (3) There is no oil stain on the surface, and the precipitation rate approaches zero;

[0122] (4) Suitable for high-temperature curing process of aviation composite materials.

[0123] Example 3: Thioester bond grafted polysiloxane main chain + fatty acid amide side chain

[0124] S1: Synthesis of thermosensitive long-chain main chain (construction of thioester bond)

[0125] Under nitrogen protection, 2 mmol of PDMS modified with dithiobenzoate groups was dissolved in 50 ml of THF with 3 mmol of mercaptopropyltriethoxysilane, and 2 mol% of AIBN thermal initiator was added. The reaction was heated in an oil bath at 70 °C for 6 hours, and the solvent was removed by distillation under reduced pressure to obtain a long-chain main chain of thioester bond grafted polysiloxane.

[0126] S2: Synthesis of side chain of lubricating functional group (enzyme-catalyzed amidation reaction)

[0127] 10 mmol of erucic acid (C18 unsaturated fatty acid) was mixed with 5 mmol of ethylenediamine in 40 ml of n-hexane, and 6 wt% of Novozym 435 lipase was added as a catalyst. The reaction was carried out at 80 °C for 10 hours. The enzyme catalyst was removed by filtration, and the solvent was removed by vacuum distillation to obtain erucic acid amide short-chain side chains.

[0128] S3: Side chain grafted to the main chain (ATRP catalysis)

[0129] 3 mmol of long-chain main chain and 6 mmol of short-chain side chain were mixed in 40 ml of DMF, and 2 mol% of CuBr and 0.5 mol% of PMDETA ligand were added. Atom transfer radical polymerization (ATRP) grafting was completed by reacting at 90 °C for 8 hours under nitrogen protection. The reaction solution was precipitated with an ether / water solution with a volume ratio of 5:1, filtered, and vacuum dried at 60 °C for 12 hours to obtain a non-precipitating lubricant.

[0130] For the preparation of resin samples from the non-precipitating lubricant prepared in Example 3, the specific operation steps are as follows:

[0131] 70 parts of soft PVC, 30 parts of DOP plasticizer 30%, 2 parts of calcium-zinc stabilizer 2%, and 1 part of lubricant were taken, dry mixed, and then extruded with a twin-screw extruder at a temperature of 160 - 180 °C, an extrusion pressure of 15 MPa, and a screw speed of 200 rpm.

[0132] Performance test:

[0133] (1) The thioester bond breaks at 130 °C to release the side chain;

[0134] (2) High physical entanglement recombination efficiency after cooling;

[0135] (3) Biodegradation rate ≥ 80%;

[0136] (4) Suitable for environmentally friendly resin processing, medical materials, and UV resin systems.

[0137] Comparative Example 1: Based on the resin preparation method of Example 1, the lubricant was changed to an ester bond lubricant, and the specific parameter changes are as follows:

[0138] (1) Resin type: Bisphenol A epoxy resin;

[0139] (2) Lubricant specification: The long-chain main chain is connected to the polyethylene and silicone side chain through an ester bond (COO);

[0140] Comparative Example 2: Based on the resin preparation method of Example 1, the lubricant was changed to an unmodified silicone oil lubricant, and the specific parameter changes are as follows:

[0141] (1) Resin type: Bisphenol A epoxy resin;

[0142] (2) Silicone oil specification: Methyl silicone oil with Mn = 5000 and viscosity of 350 cSt;

[0143] (3) Addition amount: 10% silicone oil needs to be added to achieve a 15% decrease in viscosity;

[0144] Comparative Example 3: Prepare samples with a low-temperature curing resin, doped with a lubricant with a fracture temperature mismatch and no precipitation. The specific parameter changes are as follows:

[0145] (1) Lubricant specification: Long-chain main-chain lubricant with Diels-Alder bond, fracture temperature 150 °C;

[0146] (2) Resin specification: Low-temperature curing epoxy resin, curing temperature 120 °C;

[0147] Comparative Example 4: Based on the resin sample preparation method of Example 3, the lubricant is changed to calcium stearate lubricant

[0148] (1) Resin type: PVC;

[0149] (2) Lubricant specification: Calcium stearate powder with particle size ≤ 50 μm, addition amount 8%.

[0150] Comparative Example 5: Based on the resin preparation method of Example 1, the lubricant is changed to polyethylene wax

[0151] (1) Resin type: Bisphenol A epoxy resin;

[0152] (2) Lubricant specification: Low molecular weight polyethylene wax with Mn = 2,000 and melting point 110 °C.

[0153] Comparative Example 6: Based on the resin preparation method of Example 1, the lubricant is changed to a high molecular weight DA main chain

[0154] (1) Resin type: Bisphenol A epoxy resin;

[0155] (2) Lubricant specification: Diels-Alder bond long-chain main chain with Mn = 30000, fracture temperature 150 °C.

[0156] Performance test:

[0157] 1. Fracture temperature test. Reference standard: ASTM E794 / ISO 11357. Test conditions: Heating rate 10 °C / min, nitrogen protection. Pass / fail criterion: Effective response ΔH ≥ 50 J / g.

[0158] 2. Viscosity Decrease Rate Test. Sample Preparation: The resin and the lubricant are mixed in proportion and pre-cured to a molten state. Reference Standard: ASTM D7175 / ISO 6721. Test Conditions: At the fracture temperature. Pass / Fail Criterion: The decrease rate ≥ 30%.

[0159]

[0160] 3. Precipitation Rate Test. Sample Preparation: Cured resin sheet (Dimensions: 100mm * 100mm * 2mm). Test Conditions: Aging at 50°C and RH50% for 24h. Collection of Precipitates: Wipe the surface precipitates with ethanol and weigh after drying. No-Precipitation Criterion: The precipitation rate ≦ 0.5%.

[0161]

[0162] 4. Mechanical Retention Rate Test. Reference Standard: ASTM D638 (Type I dumbbell-shaped specimen). Test Conditions: Tensile rate of 5mm / min at room temperature. Pass / Fail Criterion: The retention rate ≥ 90%.

[0163]

[0164] 5. Environmental Friendliness Test. Reference Standard: ISO 14855 (Determination of aerobic biodegradability under controlled composting conditions). Test Conditions: 58 ± 2°C, RH50 - 60%, 180 days. Pass / Fail Criterion: The biodegradation rate ≥ 60%.

[0165]

[0166] 6. Molecular Weight Change Test. Reference Standard: ASTM D6474. Test Conditions: Mobile phase - tetrahydrofuran (THF), flow rate - 1.0 mL / min, differential refractive index detector (RI). Pass / Fail Criterion: The molecular weight Mn < 2000 after the main chain breaks.

[0167] The test results are shown in Table 1. The performance results of Examples 1 - 3 and Comparative Examples 1 - 6 are analyzed as follows:

[0168] (1) The viscosity decreases significantly

[0169] The fracture temperature of the lubricant in Example 1 is 150°C and that in Example 2 is 180°C, which are more suitable for high-temperature curing processes;

[0170] When in use, the viscosity decrease rates are 32% and 25% respectively, and the viscosity decrease is significantly higher than that of traditional lubricants;

[0171] The fracture temperature of the lubricant in Example 3 is 120°C, with excellent low-temperature responsiveness, and the viscosity decrease rate is 38%, which is suitable for the UV curing system;

[0172] Although graft designs were used in Comparative Examples 3 and 6, due to mismatched fracture temperatures or excessively high main-chain molecular weights, the degree of main-chain fracture was insufficient, resulting in a significantly lower viscosity reduction rate than in Examples 1-3.

[0173] (2) Precipitation rate and mechanical properties

[0174] Through the reorganization during the main-chain cooling process in Examples 1-3, the precipitation rates were all ≤ 0.5%. In contrast, due to traditional designs (ester bonds, unmodified silicone oil) or mismatched fracture temperatures in the comparative examples, the precipitation rates were generally greater than 3. This shows that under the same conditions, Examples 1-3 effectively controlled the precipitation problem and achieved a precipitation-free effect.

[0175] (3) Excellent mechanical properties retention

[0176] The mechanical retention rate of Example 1 was ≥ 97%. After the main-chain reorganization, physical entanglements were formed with the resin, avoiding mechanical loss. In contrast, due to poor compatibility, the tensile strength decreased by approximately 30% compared to the best performance of the examples.

[0177] (4) Environmental friendliness

[0178] Example 3 had the best environmental friendliness (biodegradation rate ≥ 80%) due to the degradable thioester bond. Although the biodegradation rate of the lubricant was limited, there was a significant improvement compared to other comparative examples in terms of green production.

[0179] Table 1

[0180]

[0181] By comparing Examples 1-3 with Comparative Examples 1-6, it can be shown that the present invention constructs a high-molecular-weight thermosensitive main chain by introducing reversible covalent bonds (Diels-Alder bond, acetal bond, thioester bond), achieving an intelligent response of the lubricant function. At the same time, the side chain is fixed by carbon-carbon bonds or fluorocarbon segments to avoid reactions with resin curing agents and catalysts, eliminating the risk of hydrolysis failure of traditional ester bond lubricants. High-efficiency synthesis techniques such as thiol-ene click reaction and enzyme-catalyzed amidation are used to avoid multi-step modification of traditional lubricants (such as esterification, silane coupling). Finally, by regulating the main-chain type (polyolefin, perfluoropolyether, polysiloxane) and fracture temperature (100 - 200 °C), it covers polar / non-polar systems such as epoxy resin, polyimide, PVC, and UV resin, and is extended to high-end fields such as electronics, aviation, and medical. In summary, the present invention has made significant breakthroughs in processing fluidity, anti-precipitation, mechanical retention rate, and environmental friendliness through the "thermosensitive fracture-cooling reorganization" dynamic mechanism.

[0182] The above has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and all these changes and improvements fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A non-precipitating lubricant, characterized in that: It includes a long-chain main chain containing reversible covalent bonds grafted with short-chain side chains containing lubricating functional groups. The long-chain main chain is one of Diels-Alder bond-grafted polyolefin, acetal bond-grafted perfluoropolyether, or thioester bond-grafted polysiloxane. The short-chain side chain corresponds to one of thiol-siloxane composite short chains, fluorocarbon-siloxane composite short chains, or fatty acid amides. The long-chain main chain and the short-chain side chain are connected by carbon-carbon bonds or fluorocarbon chain segments.

2. The preparation method of the non-precipitating lubricant according to claim 1, characterized in that, It includes the following steps: S1: Synthesis of the long-chain main chain containing reversible covalent bonds. Under the protection of inert gas, take a functional polymer main chain precursor as one of polyolefin, perfluoropolyether, and polysiloxane, add the corresponding amount of reversible covalent bond-grafted monomer, dissolve it in a solvent, add an initiator or catalyst, heat and react at high temperature, and perform post-treatment after cooling to obtain a long-chain main chain containing reversible covalent bonds; S2: Synthesis of the short-chain side chain with lubricating function. Take a lubricating group containing an unsaturated bond and a compound containing active hydrogen to carry out thiol-ene click reaction or enzyme-catalyzed amidation reaction, add a photo / radical initiator, and initiate the reaction by ultraviolet light or heat. After the reaction, remove the solvent by vacuum distillation to obtain a short-chain side chain containing lubricating functional groups; S3: Side chain grafting and passivation. Mix the long-chain main chain and the short-chain side chain according to a molar ratio of 1:2 - 6, add a radical initiator or a metal catalytic system, carry out a photothermal reaction or a catalytic reaction, precipitate with a selective solvent after the reaction, and then filter and dry in vacuum to obtain a non-bleeding lubricant.

3. The non-bleeding lubricant according to claim 1 or 2, characterized in that: The long-chain main chain is Diels-Alder bond-grafted polyolefin, and the number-average molecular weight Mn is 5000 - 20000; The short-chain side chain is a thiol-siloxane composite short chain; The chain length of the siloxane segment is C2 - C4; The long-chain main chain and the short-chain side chain are grafted through catalytic carbon-carbon bonds; The breaking temperature of the non-bleeding lubricant is 120 - 180 °C; The non-bleeding lubricant is applicable to polar resins.

4. The non-bleeding lubricant according to claim 1 or 2, characterized in that: The long-chain main chain is acetal bond-grafted perfluoropolyether, and the number-average molecular weight Mn is 8000 - 15000; The short-chain side chain is a fluorocarbon-siloxane composite short chain; The chain length of the fluorocarbon segment is C6 - C7; The long-chain main chain and the short-chain side chain are grafted through atom transfer radical polymerization; The breaking temperature of the non-bleeding lubricant is 150 - 200 °C; The non-bleeding lubricant is applicable to polar / non-polar resins.

5. The non-bleeding lubricant according to claim 1 or 2, characterized in that: The long-chain main chain is thioester bond-grafted polysiloxane, and the number-average molecular weight Mn is 3000 - 10000; The short-chain side chain is fatty acid amide; The chain length of the fatty acid amide segment is C18 - C20; The long-chain main chain and the short-chain side chain are grafted through radical polymerization; The breaking temperature of the non-bleeding lubricant is 100 - 160 °C; The non-bleeding lubricant is applicable to non-polar resins.

6. The preparation method according to claim 2, characterized in that: In step S1, when synthesizing the main chain by Diels-Alder reaction, it specifically includes: Under nitrogen protection, 10–15 g of graft monomer-modified polyolefin and 1–1.5 mmol of furan compound are dissolved in 50–60 mL of solvent; 0.1–0.3 mol% of acidic catalyst is added; The reaction is carried out in an oil bath at 110–120 °C for 6–8 hours; After cooling, the precipitate is filtered and dried in vacuo at 60–70 °C for 10–12 hours to obtain the long-chain backbone of Diels-Alder bond-grafted polyolefin.

7. The preparation method according to claim 2, characterized in that: In step S1, when synthesizing the backbone by acetal reaction, it specifically includes: Under nitrogen protection, 10–15 g of perfluoropolyether and 1.5–2 mmol of acetal-functional monomer are dissolved in 50–60 mL of solvent; 0.5–0.7 mol% of acidic ionic liquid catalyst is added; The reaction is carried out in an oil bath at 150–160 °C for 8–10 hours; After cooling, the reaction solution is neutralized with NaHCO3, the organic phase is separated by layering and obtained by vacuum distillation to obtain the long-chain backbone of acetal bond-grafted perfluoropolyether.

8. The preparation method according to claim 2, characterized in that: In step S1, when synthesizing the backbone by thioester bond reaction, it specifically includes: Under nitrogen protection, 10–15 g of modified polysiloxane and 2–3 mmol of mercapto-modified siloxane are dissolved in 40–50 mL of solvent; 1–2 mol% of thermal initiator is added; The reaction is carried out in an oil bath at 60–70 °C for 5–6 hours; The solvent is removed by vacuum distillation to obtain the long-chain backbone of thioester bond-grafted polysiloxane.

9. The preparation method according to claim 2, characterized in that: After the grafting in step S3 is completed, selective precipitation purification is carried out using acetone:water = 3:1, ethanol:water = 2:1 or ether:water = 5:

1.

10. The non-precipitating lubricant according to claim 1 or 2, characterized in that: The long-chain backbone of the non-precipitating lubricant resin breaks at the processing temperature, the molecular weight is reduced to less than 2000, and it can be reversibly reorganized after cooling, and the tensile strength retention rate is ≥95%.

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