A structurally controllable polydimethylsiloxane poly-ɛ-caprolactone block polymer diol and its preparation method

Abstract

The present application provides a structure-controllable polydimethylsiloxane polyɛ-caprolactone block polymer diol and a preparation method thereof. The method comprises the following steps: S1: reacting a diol and ɛ-caprolactone under the catalysis of a first catalyst to obtain a polyɛ-caprolactone diol; S2: reacting the polyɛ-caprolactone diol and a haloolefin under the catalysis of a second catalyst to obtain a double-terminal olefin-based polyɛ-caprolactone; S3: reacting the double-terminal olefin-based polyɛ-caprolactone with a double-terminal hydrogen polydimethylsiloxane under the catalysis of a third catalyst to obtain a double-terminal hydrogen polydimethylsiloxane-grafted polyɛ-caprolactone; and S4: reacting the double-terminal hydrogen polydimethylsiloxane-grafted polyɛ-caprolactone with an enol compound under the catalysis of a fourth catalyst to obtain a polydimethylsiloxane polyɛ-caprolactone block polymer diol. The block polymer diol obtained by this preparation method can be used to improve the mechanical properties and durability of polymer materials.

Description

Technical Field

[0001] The present application relates to the technical field of polymer compound synthesis, and in particular to a structure-controllable polydimethylsiloxane poly-ɛ-caprolactone block polymer diol and a preparation method thereof. Background Art

[0002] Polymer diols are important raw materials for polyurethane elastomers and related polymer materials. Their molecular structure and properties play a decisive role in the comprehensive performance of downstream materials, including mechanical properties, durability, and flexibility. Polydimethylsiloxane diol is widely used in polymer materials due to its excellent flexibility, hydrophobicity, and weather resistance. Poly-ε-caprolactone diol, on the other hand, exhibits excellent mechanical properties and biocompatibility and is commonly used in medical and biodegradable materials. The complementary properties of these two diols give them potential synergistic advantages in material systems.

[0003] However, in the prior art, the combination of polydimethylsiloxane diol and poly-ε-caprolactone diol is generally carried out by adding both as raw materials to the material system through physical mixing. This physical mixing method is simple, but it often leads to obvious phase separation of the two polymer segments on a microscopic scale, poor interfacial compatibility, and difficulty in achieving effective integration of the two in the system. Especially under long-term use or complex environments, failure problems such as interfacial debonding, delamination, and microcracks are prone to occur within the material, seriously affecting the mechanical properties and durability of the material. In addition, physical mixing cannot achieve the ordered arrangement of molecular segments and effective control of terminal functional groups, resulting in insufficient performance stability of the polyol system.

[0004] Therefore, how to overcome the problems of segment phase separation and insufficient interfacial bonding caused by existing physical mixing methods and achieve orderly combination and synergy of the two types of segments at the molecular level remains a technical problem that technicians in this field urgently need to solve. Summary of the Invention

[0005] The present application provides a structurally controllable polydimethylsiloxane poly-ɛ-caprolactone block polymer diol and a preparation method thereof, which can achieve ordered integration of polydimethylsiloxane segments and poly-ε-caprolactone segments at the molecular level, aiming to overcome the problems of obvious segment phase separation, poor interfacial compatibility, and disordered molecular segment distribution that exist in the prior art when polydimethylsiloxane and poly-ɛ-caprolactone block polymers are simply physically blended and added.

[0006] In a first aspect, the present application provides a method for preparing a polydimethylsiloxane poly-ɛ-caprolactone block polymer diol, comprising the following steps:

[0007] S1: reacting a diol and ɛ-caprolactone under the catalysis of a first catalyst, so that the ɛ-caprolactone ring is opened and reacts with the hydroxyl group of the diol to obtain poly ɛ-caprolactone diol;

[0008] S2: reacting poly-ɛ-caprolactone diol and halogenated olefin under the catalysis of a second catalyst, so that olefin groups are substituted and grafted onto both ends of the poly-ɛ-caprolactone diol to obtain double-terminal olefin-based poly-ɛ-caprolactone;

[0009] S3: reacting a double-terminal olefin-based polyɛ-caprolactone with a double-terminal hydrogen polydimethylsiloxane under the catalysis of a third catalyst, so that the double-terminal hydrogen polydimethylsiloxane is added and grafted onto both ends of the double-terminal olefin-based polyɛ-caprolactone to obtain a double-terminal hydrogen polydimethylsiloxane-grafted polyɛ-caprolactone;

[0010] S4: reacting the double-end hydrogenated polydimethylsiloxane grafted polyɛ-caprolactone with an enol compound under the catalysis of a fourth catalyst, so that both ends of the double-end hydrogenated polydimethylsiloxane grafted polyɛ-caprolactone are addition-grafted with the enol compound to obtain a polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane block polymer diol as the polydimethylsiloxane polyɛ-caprolactone block polymer diol.

[0011] According to the present application, this preparation method enables the orderly grafting and efficient integration of polydimethylsiloxane segments and poly-ɛ-caprolactone segments at the molecular level, forming a block polymer diol with a regular structure, controllable molecular weight, and uniform terminal functional groups. The resulting block polymer diol not only exhibits excellent interfacial compatibility and microphase structural stability in the subsequent preparation of polymer systems such as polyurethane materials, but also effectively inhibits segment phase separation, further improving the mechanical properties and durability of the final material.

[0012] Specifically, in step S1, the diol acts as an initiator to undergo ring-opening polymerization with ɛ-caprolactone. The efficient catalytic effect of the first catalyst is utilized to achieve controllable initiation growth and molecular weight regulation of the polyɛ-caprolactone chain segments, thereby obtaining uniformly distributed polyɛ-caprolactone diol. In step S2, the halogenated olefin is grafted onto both ends of the polyɛ-caprolactone diol through a nucleophilic substitution reaction under the action of the second catalyst, thereby generating a double-terminal olefin-based structure, thereby ensuring efficient subsequent grafting with the siloxane chain segments. In step S3, the double-terminal hydrogen polydimethylsiloxane and the double-terminal olefin-based polyɛ-caprolactone undergo an addition reaction under the action of the third catalyst, thereby achieving the orderly introduction of the polydimethylsiloxane chain segments and forming a molecular-level coupling of the flexible polydimethylsiloxane and the rigid polyɛ-caprolactone. In step S4, the enol compound is added to the Si-H group at the end of the polymer chain to form a double-terminal hydroxyl-terminated structure, thereby enhancing the reactivity and structural controllability of the final block polymer diol.

[0013] Through the sequential design of functional group activity and the efficient matching of the catalyst system in each step, the orderly integration of the chain segments and the full utilization of interfacial synergy are ensured. The resulting polydimethylsiloxane poly-ɛ-caprolactone block polymer diol overcomes the drawbacks of physical mixing methods, such as interfacial segment separation, structural disorder, and unstable performance. Therefore, it can be used as a polyol raw material for polymer materials such as polyurethane, resulting in polymer materials with excellent mechanical properties and durability.

[0014] In some embodiments, in step S1, the relative molecular mass of the diol is less than 150. Based on the above embodiment, the diol with a lower molecular weight can act as an initiator to provide more active end groups in the ring-opening polymerization of ɛ-caprolactone, thereby improving the uniform initiation of the polymer segments and the controllability of the molecular weight, thereby helping to achieve the structural uniformity and precise control of the terminal functional groups of the target poly-ɛ-caprolactone diol.

[0015] In some embodiments, the diol includes at least one of ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and 1,4-cyclohexanedimethanol.

[0016] In some embodiments, in step S1, the molar ratio of the diol to the ε-caprolactone is 1:(2-6). Based on the above embodiment, a reasonable molar ratio of the diol to the ε-caprolactone can effectively control the initiation density and segment growth rate of the polymerization reaction, avoid the occurrence of side reactions, and simultaneously achieve regulation of the polymer molecular weight, ensuring that the resulting poly ε-caprolactone diol has a more uniform segment distribution and higher structural regularity.

[0017] In some embodiments, in step S1, the first catalyst includes an organotin catalyst, and the amount of the first catalyst added is 0.1% to 0.5% of the total mass of the diol and ε-caprolactone. Based on the above embodiment, the organotin catalyst can achieve efficient ring-opening polymerization of ε-caprolactone under relatively mild conditions, and a reasonable range of catalyst addition helps to improve catalytic activity and reaction rate, reduce the formation of byproducts, and further ensure the structural uniformity and molecular weight controllability of the poly-ɛ-caprolactone diol.

[0018] In some embodiments, the organotin catalyst includes at least one of stannous octoate, dibutyltin dilaurate, dioctyltin dilaurate, and dibutyltin acetate.

[0019] In some embodiments, in step S1, the reaction conditions include reacting at 110-150° C. for 8-12 hours. Based on the above embodiments, a reasonable reaction temperature and time are matched to the catalyst activity, ensuring an efficient and controlled polymerization process, further improving the molecular weight uniformity of the poly-ɛ-caprolactone diol and the precise control of the terminal functional groups.

[0020] In some embodiments, in step S2, the molar ratio of the poly-ɛ-caprolactone diol to the halogenated olefin is 1:(2.1-2.2). Based on the above embodiment, a moderate excess of halogenated olefin can improve the reaction efficiency of the halogenated olefin with the hydroxyl groups at the ends of the poly-ɛ-caprolactone diol, ensure the complete conversion of the terminal groups of the generated double-terminal olefin-based poly-ɛ-caprolactone, avoid the formation of residual hydroxyl groups or by-products, and thus facilitate the smooth progress of the subsequent siloxane grafting step and the orderly integration of the molecular structure of the final product.

[0021] In some embodiments, in step S2, the halogenated olefin includes at least one of allyl chloride, butyl chloride, and allyl bromide. Based on the above embodiments, the appropriate selection of the halogenated olefin species can improve the rate and selectivity of the nucleophilic substitution reaction with the terminal hydroxyl group of the poly (ɛ-caprolactone) diol, further ensuring the terminal structural integrity of the diolefin-based poly (ɛ-caprolactone) and the efficient subsequent addition grafting reaction.

[0022] In some embodiments, in step S2, the second catalyst comprises at least one of sodium hydroxide, potassium hydroxide, sodium methoxide, and sodium ethoxide, and the molar ratio of the poly (gamma)-caprolactone diol to the second catalyst is 1:(2-2.1). Based on the above embodiments, the appropriate selection of a catalyst and its appropriate use can effectively increase the rate of the substitution reaction, inhibit the occurrence of side reactions, and make the resulting double-terminal olefin-based poly (gamma)-caprolactone structure more regular, with a uniform distribution of terminal functional groups, which is beneficial for subsequent addition grafting and ordered segment integration.

[0023] In some embodiments, step S2 is carried out at 100-130°C for 1-3 hours. Based on the above embodiments, the rational combination of reaction temperature and time, combined with the catalytic effect of the second catalyst, can promote the efficient end-group substitution grafting reaction, reduce the formation of side reactions, further improve the structural uniformity of the diolefin-terminated poly-ɛ-caprolactone, and facilitate the smooth progress of the subsequent addition grafting reaction.

[0024] In some embodiments, in step S3, the molar ratio of the dual-terminal olefin-based poly (ɛ-caprolactone) to the dual-terminal hydrogenated polydimethylsiloxane is 1:(2.0-2.1). Based on the above embodiment, in step S3, the aforementioned ratio of dual-terminal hydrogenated polydimethylsiloxane can improve the efficiency of addition grafting with the dual-terminal olefin-based poly (ɛ-caprolactone), ensure that the dual-terminal hydrogenated polydimethylsiloxane is evenly grafted to both ends of the poly (ɛ-caprolactone) segment, reduce the content of residual olefin groups at the terminals, and further enhance the molecular structure regularity of the block polymer diol.

[0025] In some embodiments, in step S3, the number average molecular weight of the dual-terminal olefin-based poly (ɛ-caprolactone) is 200 to 1000, and the number average molecular weight of the dual-terminal hydrogen-based polydimethylsiloxane is 300 to 1000. Based on the above embodiments, matching the appropriate number average molecular weight range can optimize the grafting compatibility and reactivity of the two segments, achieving ordered segment bonding at the molecular level, thereby improving the structural regularity and segment distribution uniformity of the block polymer diol. Furthermore, this number average molecular weight can reduce the problem of excessive length of a block in the block copolymer, which can lead to microphase separation of the block polymer itself in the material system.

[0026] In some embodiments, in step S3, the third catalyst includes a Custer catalyst, and the amount of the third catalyst added is 0.001% to 0.01% of the total mass of the bi-terminal olefin-based poly (ɛ-caprolactone) and the bi-terminal hydrogen-based polydimethylsiloxane. Based on the above embodiment, in step S3, the Custer catalyst has excellent catalytic activity and selectivity for the addition reaction. A reasonable amount of catalyst can promote an efficient grafting reaction between the bi-terminal hydrogen-based polydimethylsiloxane and the bi-terminal olefin-based poly (ɛ-caprolactone), while suppressing side reactions, further improving the molecular weight uniformity of the block polymer diol and the integrity of the terminal functional groups.

[0027] It should be noted that the Karstedt catalyst has a well-known meaning in the art, and its chemical name is 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum.

[0028] In some embodiments, in step S3, the reaction conditions include: reacting at 80-150°C for 2-6 hours. Based on the above embodiment, in step S3, the moderate reaction temperature and time, combined with the efficient catalytic effect of the third catalyst, can ensure the complete completion of the addition grafting reaction, reduce the formation of byproducts, and improve the structural regularity and segment distribution uniformity of the block polymer diol.

[0029] In some embodiments, in step S4, the molar ratio of the double-end hydrogenated polydimethylsiloxane grafted poly-ɛ-caprolactone to the enol compound is 1:(2.01-2.1). Based on the above embodiment, a moderate excess of the enol compound can promote the complete addition reaction with the terminal Si-H groups of the double-end hydrogenated polydimethylsiloxane grafted poly-ɛ-caprolactone, avoid residual Si-H groups, and further improve the terminal functional group uniformity and molecular structure regularity of the block polymer diol.

[0030] In some embodiments, in step S4, the enol compound includes at least one of allyl alcohol and butanol. Based on the above embodiments, the appropriate selection of the enol compound can improve the selectivity and efficiency of the terminal addition reaction, reduce side reactions, and ensure a high rate of terminal functional group introduction and uniform molecular segment distribution in the block polymer diol.

[0031] In some embodiments, in step S4, the fourth catalyst includes [1,3-dicyclohexyl-imidazol-2-yl][1,3-divinyl-1,1,3,3,-tetramethyldisiloxane]platinum, and the amount of the fourth catalyst added is 0.001% to 0.005% of the total mass of the double-terminated hydrogen polydimethylsiloxane-grafted poly-ɛ-caprolactone and the enol compound. Based on the above embodiment, the selection of this catalyst and its appropriate use can significantly improve the addition efficiency of Si-H groups to the enol compound, inhibit the occurrence of side reactions, and further enhance the structural regularity of the block polymer diol and the integrity of the introduced terminal functional groups.

[0032] In some embodiments, in step S4, the reaction conditions include: reacting at 80-150° C. for 3-8 hours. Based on the above embodiments, the appropriate matching of reaction temperature and time, as well as the synergistic effect of the catalyst, can effectively promote the complete addition grafting reaction, reduce residual unreacted groups, and improve the segment structure order and terminal activity consistency of the block polymer diol.

[0033] In some embodiments, the method further comprises:

[0034] S5: reacting a polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane block polymer diol with ɛ-caprolactone under the catalysis of a fifth catalyst, so that the ɛ-caprolactone ring-opens and reacts with the hydroxyl group of the polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane block polymer diol to obtain a polyɛ-caprolactone-polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane-polyɛ-caprolactone block polymer diol as the polydimethylsiloxane-polyɛ-caprolactone block polymer diol.

[0035] In some of the above embodiments, ɛ-caprolactone is ring-opening polymerized under the catalytic action of the catalyst and reacts with the hydroxyl groups at the ends of the polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane block polymer diol, thereby achieving further extension and integration of the chain segments and forming a molecular structure with symmetrical end coating. This symmetrical coating of polyɛ-caprolactone introduced at the end of the chain segment can not only achieve the extension of the entire chain segment without making the polydimethylsiloxane chain segment too long individually, avoiding the interfacial compatibility problem caused by the excessive proportion of a certain block, but also improve the flexible transition and buffering capacity between the chain segments, reducing interfacial defects and mechanical stress concentration; in this way, the molecular weight of the block polymer diol can be increased without affecting the compatibility between the blocks, further improving the molecular structure regularity, molecular weight controllability and interfacial compatibility of the resulting block polymer diol; in particular, the outer layer of symmetrical polyɛ-caprolactone chain segment coating not only provides better terminal reactivity, but also effectively avoids the uneven aggregation of the interface caused by excessive elongation of the polydimethylsiloxane chain segment, thereby further improving the mechanical properties and durability of the final material.

[0036] In some embodiments, in step S5, the molar ratio of the polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane block polymer diol to the ɛ-caprolactone is 1:(2-6). Based on the above embodiment, a moderate amount of ɛ-caprolactone can ensure the complete further ring-opening polymerization of the segment ends, avoid the problem of uneven segment extension caused by residual hydroxyl groups or insufficient reaction, and thus achieve orderly extension of the polymer molecular segments and uniformity of the terminal functional groups, thereby improving the structural regularity and molecular weight controllability of the resulting polydimethylsiloxane polyɛ-caprolactone block polymer diol.

[0037] In some embodiments, in step S5, the fifth catalyst includes an organotin catalyst, and the amount of the fifth catalyst added is 0.1% to 0.5% of the total mass of the polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane block polymer diol and ɛ-caprolactone. Based on the above embodiments, the organotin catalyst has excellent catalytic activity and selectivity. A reasonable catalyst dosage not only promotes efficient ring-opening polymerization of ɛ-caprolactone but also inhibits side reactions, further improving the integrity of the terminal segment grafting and the segment order of the resulting polymer.

[0038] It should be noted that the organotin catalyst can be selected according to the type of the first catalyst in step S1.

[0039] In some embodiments, in step S5, the reaction conditions include reacting at 110-150° C. for 8-12 hours. Based on the above embodiments, the appropriate reaction temperature and reaction time, combined with the efficient catalytic effect of the catalyst, can ensure efficient and uniform terminal ring-opening polymerization, reduce byproducts and sudden changes in segment distribution, and further ensure the molecular structural integrity and uniformity of the segment distribution of the block polymer diol.

[0040] As an example, Figure 1 The synthesis path diagram of one embodiment of the present application is shown, specifically, the diol reacts with ɛ-caprolactone in the presence of a stannous octoate catalyst to obtain polyɛ-caprolactone diol; the polyɛ-caprolactone diol then reacts with allyl chloride to obtain double-terminal allyl poly-ɛ-caprolactone; the double-terminal allyl poly-ɛ-caprolactone then reacts with double-terminal hydrogen polydimethylsiloxane to obtain double-terminal hydrogen polydimethylsiloxane grafted polyɛ-caprolactone; the double-terminal hydrogen polydimethylsiloxane grafted polyɛ-caprolactone The product is then reacted with allyl alcohol to obtain polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane block polymer diol; the polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane block polymer diol is then reacted with ɛ-caprolactone to obtain polyɛ-caprolactone-polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane-polyɛ-caprolactone block polymer diol as polydimethylsiloxane-polyɛ-caprolactone block polymer diol.

[0041] In a second aspect, the present application provides a polydimethylsiloxane polyɛ-caprolactone block polymer diol, which is prepared according to the method described in any embodiment of the first aspect.

[0042] According to the present application, the polydimethylsiloxane-poly-ɛ-caprolactone block polymer diol has a regular structure, controllable molecular weight, and uniform terminal functional groups, enabling ordered integration of polydimethylsiloxane and poly-ɛ-caprolactone segments at the molecular level. During the subsequent preparation of polymer materials, the polymer diol exhibits excellent interfacial compatibility and uniform segment distribution, overcoming the drawbacks of existing physical mixing methods, such as segment interfacial separation, structural disorder, and unstable performance. It possesses improved mechanical properties and durability, making it particularly suitable for the preparation of high-performance polyurethane materials.

[0043] In a third aspect, the present application provides a polyurethane material comprising the following raw materials in parts by weight:

[0044] 100 parts of isocyanate, 80 to 120 parts of the polydimethylsiloxane poly-ɛ-caprolactone block polymer diol according to any embodiment of the second aspect, 10 to 20 parts of a chain extender, and 0.1 to 0.5 parts of a catalyst.

[0045] According to the present application, the polyurethane material is obtained by introducing the polydimethylsiloxane polyɛ-caprolactone block polymer diol described in the second aspect into the polyurethane matrix, and the polydimethylsiloxane segment and the polyɛ-caprolactone segment achieve molecular-level ordered integration and interface synergy in the polyurethane network.

[0046] Specifically, the introduction of polydimethylsiloxane segments provides flexibility and hydrophobicity, making the material more compliant and resilient when subjected to external forces. The poly-ɛ-caprolactone segments impart excellent mechanical strength and toughness, effectively resisting damage from external forces. Through the ordered arrangement of the block segments and the intermolecular interfacial coupling, a flexible buffer layer is formed between the polydimethylsiloxane and poly-ɛ-caprolactone segments, reducing stress concentration and microcrack initiation at the interface, thereby achieving uniform stress transfer and efficient energy dissipation.

[0047] Furthermore, the low surface energy and excellent weather resistance of the polydimethylsiloxane segments, combined with the good interfacial affinity of the poly-ɛ-caprolactone segments, enable the polyurethane material to maintain excellent mechanical properties and flexibility, exhibiting outstanding fatigue resistance and durability even under long-term use and complex environmental conditions. Overall, this polyurethane material not only overcomes the existing issues of segment interfacial separation and performance fluctuations caused by the physical mixing of polysiloxane diol and poly-ɛ-caprolactone diol, but also achieves an overall improvement in the material's mechanical properties and durability, making it particularly suitable for applications with demanding long-term service requirements, such as high-performance elastomers and sealants.

[0048] In some embodiments, the raw materials further include 1 to 5 parts of an imidazole-based silane coupling agent.

[0049] In some of the above embodiments, the inventors discovered that although chemically bonding polydimethylsiloxane segments to polyɛ-caprolactone segments to form a block polymer can improve the compatibility of the two segments in the system to a certain extent, allowing them to serve together as the soft segment of the polyurethane material, due to the large difference in polarity between the polydimethylsiloxane segments and the polyɛ-caprolactone segments, there is still a difference in the interfacial compatibility between the polydimethylsiloxane segments and the polyɛ-caprolactone segments in the soft segment region, which easily leads to a microphase separation trend. By further introducing an imidazole-based silane coupling agent into the material, taking full advantage of its unique amphiphilic structure and multi-point interfacial bridging ability, it is possible to synergistically improve the interfacial bonding strength between the block polyol segments and between the block polyol and the hard segment.

[0050] Specifically, the imidazole moiety of the imidazole-based silane coupling agent is rich in nitrogen heterocyclic structures, exhibiting strong hydrogen bond acceptor / donor properties and a certain polar affinity. This allows it to form multiple hydrogen bonds and electrostatic interactions with the poly(ɛ-caprolactone) segments or hard segments (isocyanate polymer segments) within the polyurethane network, enhancing interfacial polarity matching. Furthermore, the siloxane backbone of the imidazole-based silane coupling agent exhibits excellent hydrophobicity and flexible compatibility with the polydimethylsiloxane segments, enabling flexible entanglement and compatible adsorption with the polydimethylsiloxane segments at the molecular level. Through this amphiphilic, synergistic interfacial bridging effect, the imidazole-based silane coupling agent can significantly mitigate the compatibility differences between the polydimethylsiloxane and poly(ɛ-caprolactone) segments, reducing the occurrence of microphase separation and improving the flexibility and integrity of the interfacial transition zone.

[0051] Furthermore, imidazole-based silane coupling agents can also undergo siloxane condensation reactions in the presence of moderate moisture during the use of polyurethane materials, further inhibiting their migration and ensuring interfacial stability under long-term service conditions. Through the synergistic effect of these multiple mechanisms, the introduction of imidazole-based silane coupling agents can effectively enhance the interfacial bonding and compatibility of polyurethane material systems, further improving the mechanical properties and durability of polyurethane materials.

[0052] The inventors have also discovered that the use of imidazole-based silane coupling agents offers the advantage of being chemically stable in polyurethane systems. However, other groups that can act as hydrogen bond acceptors / donors (such as amino, hydroxyl, or carboxyl groups) often exhibit a certain degree of reactivity with isocyanates, resulting in other types of silane coupling agents being unable to effectively reduce the microphase separation problem between segments in the soft segment. It should be noted that imidazole-based silane coupling agents, i.e., silane coupling agents containing imidazole groups, are well known in the art.

[0053] It should be noted that the imidazole-based silane coupling agent has a well-known meaning in the art, that is, a silane coupling agent containing an imidazole group. As an example, in one embodiment of the present application, triethoxy-3-(2-imidazol-1-yl)propanesilane is used as the silane coupling agent.

[0054] In some embodiments, the isocyanate includes at least one of diphenylmethane diisocyanate, toluene diisocyanate, p-phenylene diisocyanate, and isophorone diisocyanate. Based on the above embodiments, the appropriate selection of isocyanate can further optimize the compatibility and interfacial transition between the hard and soft segments while ensuring the formation and crosslinking density of the polyurethane network, thereby improving the mechanical properties and durability of the polyurethane material.

[0055] In some embodiments, the chain extender includes at least one of ethylene glycol, 1,3-propylene glycol, and 1,3-butanediol. Based on these embodiments, the appropriate chain extender can adjust the crosslink density and flexibility of the polyurethane network, and in combination with the flexible segments of the polydimethylsiloxane poly-ɛ-caprolactone block polymer diol, improve the mechanical properties and durability of the polyurethane material.

[0056] In some embodiments, the catalyst includes an organotin catalyst. Based on the above embodiments, the organotin catalyst can provide efficient polyurethane network reaction activity and ensure uniform reaction.

[0057] In some embodiments, the organotin catalyst includes at least one of dibutyltin dilaurate, dioctyltin dilaurate, stannous octoate, and dibutyltin acetate.

[0058] Compared with the prior art, the present invention has the following advantages:

[0059] By providing a method for preparing a polydimethylsiloxane polyɛ-caprolactone block polymer diol with an ordered structure, controllable molecular weight and terminal functional groups, the problems of poor segment compatibility, interface separation and unstable performance caused by the physical mixing method in the existing technology are overcome; the introduction of the block polymer diol can achieve efficient integration and flexible matching of the polydimethylsiloxane segment and the polyɛ-caprolactone segment at the molecular level, giving the downstream polyurethane material good mechanical properties and durability; further, by introducing an imidazole-based silane coupling agent and utilizing its amphiphilic structure and multi-point interface bridging effect, the interface compatibility between the segments and between the segments and the hard segments is significantly improved, microphase separation is reduced, the interface bonding strength is enhanced, the long-term stability of the material is guaranteed, and the mechanical properties and durability of the polyurethane material are further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0061] Figure 1 This is a synthetic route diagram of polydimethylsiloxane poly-ɛ-caprolactone block polymer diol in one embodiment of the present application;

[0062] Among them, m, n, p, q, k, t, u and v are natural numbers greater than 0, p+q=n, u+v=n. DETAILED DESCRIPTION

[0063] The various embodiments or implementation schemes in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments.

[0064] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with an embodiment or example is included in at least one embodiment or example of the present application. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0065] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0066] In the description of this specification, unless otherwise specified, "parts" refer to "parts by mass".

[0067] Below, the embodiment of the present application is described. The embodiment described below is exemplary and is only used to explain the present application, and is not to be construed as limiting the present application. Where specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. Reagents or instruments used that do not specify the manufacturer are conventional products that can be obtained commercially.

[0068] Karstedt catalyst, chemical name is 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum, CAS number is 68478-92-2;

[0069] [1,3-Biscyclohexyl-imidazol-2-yl][1,3-divinyl-1,1,3,3,-tetramethyldisiloxane] platinum, CAS No. 400758-55-6

[0070] Triethoxy-3-(2-imidazolin-1-yl)propanesilane, CAS number 58068-97-6;

[0071] N-(trimethoxysilylpropyl)imidazole, CAS number 70851-51-3.

[0072] Example 1-1

[0073] Preparation of a structure-controlled polydimethylsiloxane poly-ɛ-caprolactone block polymer diol:

[0074] (1) Add 62 g (1 mol) of ethylene glycol, 228.3 g (2 mol) of ɛ-caprolactone, and 0.29 g of stannous octoate into a 1 L four-necked flask, stir, and heat to 130 °C. React at 130 °C for 8 hours to obtain poly (ɛ-caprolactone diol).

[0075] (2) Connect a reflux tube and a condensate collection bottle to the reaction flask in step (1), add 80g (2mol) of sodium hydroxide, stir and heat to 110℃, then turn on the vacuum pump to a vacuum degree of -110mbar and keep the temperature and pressure at 110℃ for reaction. When the water output reaches the theoretical water output, stop the vacuum and cool to 70℃. When the temperature of the reactant drops to 70℃, add 156.9g (2.05mol) of allyl chloride dropwise at a constant pressure funnel for 2 hours. After the addition is complete, heat to 110℃ and react for 2 hours. Then cool to 90℃ again and turn on the vacuum to remove and collect the residual allyl chloride. After vacuum pressure for 2 hours, the reaction product can be directly filtered with a 300-mesh filter to obtain double-terminal allyl poly-ɛ-caprolactone.

[0076] (3) In a new 1L four-necked flask, 186g (0.5mol) of the double-terminal allyl poly-ɛ-caprolactone obtained in step (2) and 430g (1mol) of the double-terminal hydrogen polydimethylsiloxane A were added, and the temperature was raised to 90°C with stirring. 31mg of the Custer catalyst was added dropwise, and the temperature of the reactants was raised to 100°C. The mixture was kept at 100°C for 3 hours. The allyl content was detected by infrared spectroscopy. The disappearance of the allyl group indicated the end of the reaction.

[0077] (4) After the reactants in step (3) are cooled to room temperature, the flask is connected to a reflux condenser, and 61 g (1.05 mol) of allyl alcohol is added. The mixture is stirred for 0.5 hours to mix the reactants evenly, and then the temperature is slowly raised to 80°C and 7 mg of [1,3-dicyclohexyl-imidazol-2-yl][1,3-divinyl-1,1,3,3,-tetramethyldisiloxane]platinum is added dropwise. After the reactants have no obvious reaction heat release, the temperature is raised to 110°C and kept warm for 3 hours. After infrared detection shows that no silicon hydrogen residue is found, the temperature is lowered to 80°C, and then the residual allyl alcohol is removed by vacuum to obtain a polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane block polymer;

[0078] (5) After the reactants in step (4) are cooled to room temperature, 228.3 g (2 mol) of ɛ-caprolactone and 2.71 g of stannous octoate are added, stirred, and heated to 130° C. The mixture is reacted at 130° C. for 8 hours to obtain a polyɛ-caprolactone-polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane-polyɛ-caprolactone block polymer diol as a polydimethylsiloxane polyɛ-caprolactone block polymer diol.

[0079] Example 1-2

[0080] Preparation of a structure-controlled polydimethylsiloxane poly-ɛ-caprolactone block polymer diol:

[0081] (1) Add 62 g (1 mol) of ethylene glycol, 342.5 g (3 mol) of ɛ-caprolactone, and 0.4 g of stannous octoate into a 1 L four-necked flask, stir, and heat to 130 °C. React at 130 °C for 8 hours to obtain poly (ɛ-caprolactone diol).

[0082] (2) Connect a reflux tube and a condensate collection bottle to the reaction flask in step (1), add 80g (2mol) of sodium hydroxide, stir and heat to 110℃, then turn on the vacuum pump to a vacuum degree of -110mbar and keep the temperature and pressure at 110℃ for reaction. When the water output reaches the theoretical water output, stop the vacuum and cool to 70℃. When the temperature of the reactant drops to 70℃, add 156.9g (2.05mol) of allyl chloride dropwise at a constant pressure funnel for 2 hours. After the addition is complete, heat to 110℃ and react for 2 hours. Then cool to 90℃ again and turn on the vacuum to remove and collect the residual allyl chloride. After vacuum pressure for 2 hours, the reaction product can be directly filtered with a 300-mesh filter to obtain double-terminal allyl poly-ɛ-caprolactone.

[0083] (3) In a new 1L four-necked flask, add 244g (0.5mol) of the double-terminal allyl poly-ɛ-caprolactone obtained in step (2) and 430g (1mol) of the double-terminal hydrogen polydimethylsiloxane A. Stir and heat to 90°C. Add 34mg of Custer catalyst dropwise. Raise the temperature of the reactants to 100°C and keep at 100°C for 3 hours. Detect the allyl content by infrared. The disappearance of the allyl group indicates the end of the reaction.

[0084] (4) After the reactants in step (3) are cooled to room temperature, the flask is connected to a reflux condenser, and 61 g (1.05 mol) of allyl alcohol is added. The mixture is stirred for 0.5 hours to mix the reactants evenly, and then the temperature is slowly raised to 80°C and 7 mg of [1,3-dicyclohexyl-imidazol-2-yl][1,3-divinyl-1,1,3,3,-tetramethyldisiloxane]platinum is added dropwise. After the reactants have no obvious reaction heat release, the temperature is raised to 110°C and kept warm for 3 hours. After infrared detection shows that no silicon hydrogen residue is found, the temperature is lowered to 80°C, and then the residual allyl alcohol is removed by vacuum to obtain a polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane block polymer;

[0085] (5) After the reactants in step (4) are cooled to room temperature, 342.5 g (3 mol) of ɛ-caprolactone and 3.23 g of stannous octoate are added, stirred, and heated to 130° C. The mixture is reacted at 130° C. for 8 hours to obtain polyɛ-caprolactone-polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane-polyɛ-caprolactone block polymer diol as polydimethylsiloxane polyɛ-caprolactone block polymer diol.

[0086] Examples 1-3

[0087] Preparation of a structure-controlled polydimethylsiloxane poly-ɛ-caprolactone block polymer diol:

[0088] (1) Add 90.2 g (1 mol) of 1,4-butanediol, 456.8 g (4 mol) of ɛ-caprolactone, and 1 g of stannous octoate into a 1 L four-necked flask, stir, and heat to 130 °C. React at 130 °C for 10 hours to obtain poly (ɛ-caprolactone diol).

[0089] (2) Connect a reflux tube and a condensate collection bottle to the reaction flask in step (1), add 80g (2mol) of sodium hydroxide, stir and heat to 110℃, then turn on the vacuum pump to a vacuum degree of -110mbar and keep the temperature and pressure at 110℃ for reaction. When the water output reaches the theoretical water output, stop the vacuum and cool to 70℃. When the temperature of the reactant drops to 70℃, add 156.9g (2.05mol) of allyl chloride dropwise at a constant pressure funnel for 2 hours. After the addition is complete, heat to 110℃ and react for 2 hours. Then cool to 90℃ again and turn on the vacuum to remove and collect the residual allyl chloride. After vacuum pressure for 2 hours, the reaction product can be directly filtered with a 300-mesh filter to obtain double-terminal allyl poly-ɛ-caprolactone.

[0090] (3) In a new 2L four-necked flask, 315g (0.5mol) of the double-terminal allyl poly-ɛ-caprolactone obtained in step (2) and 726g (1mol) of the double-terminal hydrogen polydimethylsiloxane B were added, and the temperature was raised to 90°C with stirring. 50mg of the Custer catalyst was added dropwise, and the temperature of the reactants was raised to 110°C. The temperature was kept at 110°C for 3 hours. The allyl content was detected by infrared spectroscopy. The disappearance of the allyl group indicated the end of the reaction.

[0091] (4) After the reactants in step (3) are cooled to room temperature, the flask is connected to a reflux condenser, and 61 g (1.05 mol) of allyl alcohol is added. The mixture is stirred for 0.5 hours to mix the reactants evenly, and then the temperature is slowly raised to 80°C and 11 mg of [1,3-dicyclohexyl-imidazol-2-yl][1,3-divinyl-1,1,3,3,-tetramethyldisiloxane]platinum is added dropwise. After the reactants have no obvious reaction heat release, the temperature is raised to 110°C and kept warm for 4 hours. After infrared detection shows that no silicon hydrogen residue is found, the temperature is lowered to 90°C, and then the residual allyl alcohol is removed by vacuum to obtain a polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane block polymer;

[0092] (5) After the reactants in step (4) are cooled to room temperature, 456.8 g (4 mol) of ɛ-caprolactone and 4.67 g of stannous octoate are added, stirred, and heated to 130° C. The mixture is reacted at 130° C. for 8 hours to obtain a polyɛ-caprolactone-polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane-polyɛ-caprolactone block polymer diol as a polydimethylsiloxane polyɛ-caprolactone block polymer diol.

[0093] Examples 1-4

[0094] Preparation of a structure-controlled polydimethylsiloxane poly-ɛ-caprolactone block polymer diol:

[0095] (1) Add 118.2 g (1 mol) of 1,6-hexanediol, 228.3 g (2 mol) of ɛ-caprolactone, and 0.35 g of stannous octoate into a 1 L four-necked flask, stir, and heat to 130 °C. React at 130 °C for 8 hours to obtain poly (ɛ-caprolactone diol).

[0096] (2) Connect a reflux tube and a condensate collection bottle to the reaction flask in step (1), add 80g (2mol) of sodium hydroxide, stir and heat to 110℃, then turn on the vacuum pump to a vacuum degree of -110mbar and keep the temperature and pressure at 110℃ for reaction. When the water output reaches the theoretical water output, stop the vacuum and cool to 70℃. When the temperature of the reactant drops to 70℃, add 156.9g (2.05mol) of allyl chloride dropwise at a constant pressure funnel for 2 hours. After the addition is complete, heat to 110℃ and react for 2 hours. Then cool to 90℃ again and turn on the vacuum to remove and collect the residual allyl chloride. After vacuum pressure for 2 hours, the reaction product can be directly filtered with a 300-mesh filter to obtain double-terminal allyl poly-ɛ-caprolactone.

[0097] (3) In a new 1 L four-necked flask, 214.3 g (0.5 mol) of the double-terminal allyl poly-ɛ-caprolactone obtained in step (2) and 430 g (1 mol) of the double-terminal hydrogen polydimethylsiloxane A were added, the temperature was raised to 90°C with stirring, 32 mg of the Custer catalyst was added dropwise, the temperature of the reactants was raised to 110°C, and the temperature was kept at 110°C for 3 hours. The allyl content was detected by infrared spectroscopy. The disappearance of the allyl group indicated the end of the reaction.

[0098] (4) After the reactants in step (3) are cooled to room temperature, the flask is connected to a reflux condenser, and 61 g (1.05 mol) of allyl alcohol is added. The mixture is stirred for 0.5 hours to mix the reactants evenly, and then the temperature is slowly raised to 80°C and 7 mg of [1,3-dicyclohexyl-imidazol-2-yl][1,3-divinyl-1,1,3,3,-tetramethyldisiloxane]platinum is added dropwise. After the reactants have no obvious reaction heat release, the temperature is raised to 110°C and kept warm for 3 hours. After infrared detection shows that no silicon hydrogen residue is found, the temperature is lowered to 90°C, and then the residual allyl alcohol is removed by vacuum to obtain a polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane block polymer;

[0099] (5) After the reactants in step (4) are cooled to room temperature, 228.3 g (2 mol) of ɛ-caprolactone and 2.80 g of stannous octoate are added, stirred, and heated to 130° C. The mixture is reacted at 130° C. for 8 hours to obtain a polyɛ-caprolactone-polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane-polyɛ-caprolactone block polymer diol as a polydimethylsiloxane polyɛ-caprolactone block polymer diol.

[0100] Examples 1-5

[0101] Preparation of a structure-controlled polydimethylsiloxane poly-ɛ-caprolactone block polymer diol:

[0102] (1) Add 118.2 g (1 mol) of 1,6-hexanediol, 456.8 g (4 mol) of ɛ-caprolactone, and 1.1 g of stannous octoate into a 1 L four-necked flask, stir, and heat to 130 °C. React at 130 °C for 10 hours to obtain poly (ɛ-caprolactone diol).

[0103] (2) Connect a reflux tube and a condensate collection bottle to the reaction flask in step (1), add 80g (2mol) of sodium hydroxide, stir and heat to 110℃, then turn on the vacuum pump to a vacuum degree of -110mbar and keep the temperature and pressure at 110℃ for reaction. When the water output reaches the theoretical water output, stop the vacuum and cool to 80℃. When the temperature of the reactant drops to 80℃, add 156.9g (2.05mol) of allyl chloride dropwise at a constant speed for 2 hours through a constant pressure funnel. After the addition is complete, heat to 110℃ and react for 2 hours. Then cool to 90℃ again and turn on the vacuum to remove and collect the residual allyl chloride. After keeping the vacuum pressure for 2 hours, the reaction product can be directly filtered with a 300-mesh filter to obtain double-terminal allyl poly-ɛ-caprolactone.

[0104] (3) In a new 2L four-necked flask, 328.5g (0.5mol) of the double-terminal allyl poly-ɛ-caprolactone obtained in step (2) and 726g (1mol) of the double-terminal hydrogen polydimethylsiloxane B were added, and the temperature was raised to 90°C with stirring. 50mg of the Custer catalyst was added dropwise, and the temperature of the reactants was raised to 110°C. The temperature was kept at 110°C for 4 hours. The allyl content was detected by infrared spectroscopy. The disappearance of the allyl group indicated the end of the reaction.

[0105] (4) After the reactants in step (3) are cooled to room temperature, the flask is connected to a reflux condenser, and 61 g (1.05 mol) of allyl alcohol is added. The mixture is stirred for 0.5 hours to mix the reactants evenly, and then the temperature is slowly raised to 90°C and 11 mg of [1,3-dicyclohexyl-imidazol-2-yl][1,3-divinyl-1,1,3,3,-tetramethyldisiloxane]platinum is added dropwise. After the reactants have no obvious reaction heat release, the temperature is raised to 110°C and kept warm for 4 hours. After infrared detection shows that no silicon hydrogen residue is found, the temperature is lowered to 90°C, and then the residual allyl alcohol is removed by vacuum to obtain a polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane block polymer;

[0106] (5) After the reactants in step (4) are cooled to room temperature, 456.8 g (4 mol) of ɛ-caprolactone and 4.71 g of stannous octoate are added, stirred, and heated to 130° C. The mixture is reacted at 130° C. for 8 hours to obtain polyɛ-caprolactone-polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane-polyɛ-caprolactone block polymer diol as polydimethylsiloxane polyɛ-caprolactone block polymer diol.

[0107] Examples 1-6

[0108] Preparation of a structure-controlled polydimethylsiloxane poly-ɛ-caprolactone block polymer diol:

[0109] (1) Add 62 g (1 mol) of ethylene glycol, 456.8 g (4 mol) of ɛ-caprolactone, and 0.5 g of stannous octoate into a 2 L four-necked flask, stir, and heat to 130 °C. React at 130 °C for 10 hours to obtain poly (ɛ-caprolactone diol).

[0110] (2) Connect a reflux tube and a condensate collection bottle to the reaction flask in step (1), add 80g (2mol) of sodium hydroxide, stir and heat to 110℃, then turn on the vacuum pump to a vacuum degree of -110mbar and keep the temperature and pressure at 110℃ for reaction. When the water output reaches the theoretical water output, stop the vacuum and cool to 70℃. When the temperature of the reactant drops to 70℃, add 156.9g (2.05mol) of allyl chloride dropwise at a constant pressure funnel for 2 hours. After the addition is complete, heat to 110℃ and react for 2 hours. Then cool to 90℃ again and turn on the vacuum to remove and collect the residual allyl chloride. After vacuum pressure for 2 hours, the reaction product can be directly filtered with a 300-mesh filter to obtain double-terminal allyl poly-ɛ-caprolactone.

[0111] (3) In a new 2L four-necked flask, 300g (0.5mol) of the double-terminal allyl poly-ɛ-caprolactone obtained in step (2) and 430g (1mol) of the double-terminal hydrogen polydimethylsiloxane A were added, the temperature was raised to 90°C with stirring, 50mg of the Custer catalyst was added dropwise, the temperature of the reactants was raised to 110°C, and the temperature was kept at 110°C for 3 hours. The allyl content was detected by infrared spectroscopy. The disappearance of the allyl group indicated the end point of the reaction.

[0112] (4) After the reactants in step (3) are cooled to room temperature, the flask is connected to a reflux condenser, and 61 g (1.05 mol) of allyl alcohol is added. The mixture is stirred for 0.5 hours to mix the reactants evenly, and then the temperature is slowly raised to 80°C and 13 mg of [1,3-dicyclohexyl-imidazol-2-yl][1,3-divinyl-1,1,3,3,-tetramethyldisiloxane]platinum is added dropwise. After the reactants have no obvious reaction heat release, the temperature is raised to 110°C and kept warm for 3 hours. After infrared detection shows that no silicon hydrogen residue is found, the temperature is lowered to 80°C, and then the residual allyl alcohol is removed by vacuum to obtain a polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane block polymer;

[0113] (5) After the reactants in step (4) are cooled to room temperature, 456.8 g (4 mol) of ɛ-caprolactone and 3.74 g of stannous octoate are added, stirred, and heated to 130° C. The mixture is reacted at 130° C. for 8 hours to obtain a polyɛ-caprolactone-polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane-polyɛ-caprolactone block polymer diol as a polydimethylsiloxane polyɛ-caprolactone block polymer diol.

[0114] Examples 1-7

[0115] Preparation of a structure-controlled polydimethylsiloxane poly-ɛ-caprolactone block polymer diol:

[0116] (1) Add 144.2 g (1 mol) of 1,6-cyclohexanedimethanol, 456.8 g (4 mol) of ɛ-caprolactone, and 0.6 g of stannous octoate into a 2 L four-necked flask, stir, and heat to 135 °C. React at 135 °C for 10 hours to obtain poly (ɛ-caprolactone diol).

[0117] (2) Connect a reflux tube and a condensate collection bottle to the reaction flask in step (1), add 80g (2mol) of sodium hydroxide, stir and heat to 110℃, then turn on the vacuum pump to a vacuum degree of -110mbar and keep the temperature and pressure at 110℃ for reaction. When the water output reaches the theoretical water output, stop the vacuum and cool to 70℃. When the temperature of the reactant drops to 70℃, add 156.9g (2.05mol) of allyl chloride dropwise at a constant pressure funnel for 2 hours. After the addition is complete, heat to 110℃ and react for 2 hours. Then cool to 90℃ again and turn on the vacuum to remove and collect the residual allyl chloride. After vacuum pressure for 2 hours, the reaction product can be directly filtered with a 300-mesh filter to obtain double-terminal allyl poly-ɛ-caprolactone.

[0118] (3) In a new 2L four-necked flask, 342g (0.5mol) of the double-terminal allyl poly-ɛ-caprolactone obtained in step (2) and 430g (1mol) of the double-terminal hydrogen polydimethylsiloxane A were added, the temperature was raised to 90°C with stirring, 50mg of the Custer catalyst was added dropwise, the temperature of the reactants was raised to 110°C, and the temperature was kept at 110°C for 3 hours. The allyl content was detected by infrared spectroscopy. The disappearance of the allyl group indicated the end of the reaction.

[0119] (4) After the reactants in step (3) are cooled to room temperature, the flask is connected to a reflux condenser, and 61 g (1.05 mol) of allyl alcohol is added. The mixture is stirred for 0.5 hours to mix the reactants evenly, and then the temperature is slowly raised to 80°C and 13 mg of [1,3-dicyclohexyl-imidazol-2-yl][1,3-divinyl-1,1,3,3,-tetramethyldisiloxane]platinum is added dropwise. After the reactants have no obvious reaction heat release, the temperature is raised to 110°C and kept warm for 3 hours. After infrared detection shows that no silicon hydrogen residue is found, the temperature is lowered to 80°C, and then the residual allyl alcohol is removed by vacuum to obtain a polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane block polymer;

[0120] (5) After the reactants in step (4) are cooled to room temperature, 456.8 g (4 mol) of ɛ-caprolactone and 3.87 g of stannous octoate are added, stirred, and heated to 130° C. The mixture is reacted at 130° C. for 8 hours to obtain a polyɛ-caprolactone-polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane-polyɛ-caprolactone block polymer diol as a polydimethylsiloxane polyɛ-caprolactone block polymer diol.

[0121] Comparative Example 1-1

[0122] Preparation of a structure-controlled polydimethylsiloxane poly-ɛ-caprolactone block polymer diol:

[0123] (1) In a 2L four-necked flask, add 700g (0.5mol) of double-terminal hydrogen polydimethylsiloxane C and 61g (1.05mol) of allyl alcohol. Connect the flask to a reflux condenser and stir for 0.5 hours to mix the reactants evenly. Then slowly heat the flask to 80℃ and dropwise add 23mg of [1,3-dicyclohexyl-imidazol-2-yl][1,3-divinyl-1,1,3,3,-tetramethyldisiloxane]platinum. After the reactants have no obvious heat release, heat the flask to 110℃ and keep the temperature for 3 hours. After infrared detection shows no silicon hydrogen residue, cool the flask to 80℃ and then vacuum remove the residual allyl alcohol to obtain a double-terminal hydroxyl polydimethylsiloxane polymer.

[0124] (2) After the reactants in step (1) are cooled to room temperature, 228.3 g (2 mol) of ɛ-caprolactone and 2.97 g of stannous octoate are added, stirred, and heated to 130° C. The mixture is reacted at 130° C. for 8 hours to obtain polyɛ-caprolactone-polydimethylsiloxane-polyɛ-caprolactone block polymer diol as polydimethylsiloxane polyɛ-caprolactone block polymer diol.

[0125] Example 2-1

[0126] Preparation of polyurethane materials:

[0127] 100 parts of the polydimethylsiloxane poly-ɛ-caprolactone block polymer diol prepared in Example 1-1, 100 parts of diphenylmethane diisocyanate, 15 parts of 1,3-propylene glycol, 3 parts of triethoxy-3-(2-imidazol-1-yl)propanesilane, and 0.3 parts of dibutyltin dilaurate were mixed in a reaction kettle. Under nitrogen protection, the system was stirred uniformly at 60°C, then gradually heated to 80°C and stirred for 1 hour to form a prepolymer.

[0128] The obtained prepolymer was degassed under vacuum conditions, then poured into a metal mold preheated to 80° C., thermally cured at 80° C. for 2 hours, and finally post-cured at 110° C. for 2 hours to obtain a polyurethane material.

[0129] Example 2-2

[0130] Preparation of polyurethane materials:

[0131] It is substantially the same as Example 2-1, except that the polydimethylsiloxane polyɛ-caprolactone block polymer diol prepared in Example 1-2 is used instead of the polydimethylsiloxane polyɛ-caprolactone block polymer diol prepared in Example 1-1.

[0132] Example 2-3

[0133] Preparation of polyurethane materials:

[0134] It is substantially the same as Example 2-1, except that the polydimethylsiloxane polyɛ-caprolactone block polymer diol prepared in Example 1-3 is used instead of the polydimethylsiloxane polyɛ-caprolactone block polymer diol prepared in Example 1-1.

[0135] Examples 2-4

[0136] Preparation of polyurethane materials:

[0137] It is substantially the same as Example 2-1, except that the polydimethylsiloxane polyɛ-caprolactone block polymer diol prepared in Example 1-4 is used instead of the polydimethylsiloxane polyɛ-caprolactone block polymer diol prepared in Example 1-1.

[0138] Examples 2-5

[0139] Preparation of polyurethane materials:

[0140] It is substantially the same as Example 2-1, except that the polydimethylsiloxane polyɛ-caprolactone block polymer diol prepared in Example 1-5 is used instead of the polydimethylsiloxane polyɛ-caprolactone block polymer diol prepared in Example 1-1.

[0141] Examples 2-6

[0142] Preparation of polyurethane materials:

[0143] It is substantially the same as Example 2-1, except that the polydimethylsiloxane polyɛ-caprolactone block polymer diol prepared in Example 1-6 is used instead of the polydimethylsiloxane polyɛ-caprolactone block polymer diol prepared in Example 1-1.

[0144] Examples 2-7

[0145] Preparation of polyurethane materials:

[0146] It is substantially the same as Example 2-1, except that the polydimethylsiloxane polyɛ-caprolactone block polymer diol prepared in Example 1-7 is used instead of the polydimethylsiloxane polyɛ-caprolactone block polymer diol prepared in Example 1-1.

[0147] Examples 2-8

[0148] Preparation of polyurethane materials:

[0149] The process is substantially the same as Example 2-1, except that 3 parts of triethoxy-3-(2-imidazol-1-yl)propanesilane are not added.

[0150] Examples 2-9

[0151] Preparation of polyurethane materials:

[0152] The process is substantially the same as Example 2-1, except that 3-aminopropyltriethoxysilane is used instead of triethoxy-3-(2-imidazol-1-yl)propanesilane.

[0153] Example 2-10

[0154] Preparation of polyurethane materials:

[0155] The process is substantially the same as Example 2-1, except that N-(trimethoxysilylpropyl)imidazole is used instead of triethoxy-3-(2-imidazol-1-yl)propylsilane.

[0156] Comparative Example 2-1

[0157] Preparation of polyurethane materials:

[0158] It is substantially the same as Example 2-1, except that the polydimethylsiloxane poly ɛ-caprolactone block polymer diol prepared in Comparative Example 1-1 is used instead of the polydimethylsiloxane poly ɛ-caprolactone block polymer diol prepared in Example 1-1.

[0159] Comparative Example 2-2

[0160] Preparation of polyurethane materials:

[0161] 100 parts of poly-ɛ-caprolactone diol-1000, 100 parts of diphenylmethane diisocyanate, 15 parts of 1,3-propylene glycol, 3 parts of triethoxy-3-(2-imidazolin-1-yl)propanesilane, and 0.3 parts of dibutyltin dilaurate were mixed in a reaction kettle. Under nitrogen protection, the system was stirred uniformly at 60°C, then gradually heated to 80°C and stirred for 1 hour to form a prepolymer.

[0162] The obtained prepolymer was degassed under vacuum conditions, then poured into a metal mold preheated to 80° C., thermally cured at 80° C. for 2 hours, and finally post-cured at 110° C. for 2 hours to obtain a polyurethane material.

[0163] Comparative Examples 2-3

[0164] Preparation of polyurethane materials:

[0165] 70 parts of poly-ɛ-caprolactone diol-1000, 30 parts of bis(hydroxyalkyl)-terminated polydimethoxysilane (weight-average molecular weight approximately 1000), 100 parts of diphenylmethane diisocyanate, 15 parts of 1,3-propylene glycol, 3 parts of triethoxy-3-(2-imidazol-1-yl)propanesilane, and 0.3 parts of dibutyltin dilaurate were mixed in a reaction kettle. Under nitrogen protection, the system was stirred uniformly at 60°C, then gradually heated to 80°C and stirred for 1 hour to form a prepolymer.

[0166] The obtained prepolymer was degassed under vacuum conditions, then poured into a metal mold preheated to 80° C., thermally cured at 80° C. for 2 hours, and finally post-cured at 110° C. for 2 hours to obtain a polyurethane material.

[0167] Test section

[0168] With reference to GB / T 528-2009 "Rubber, vulcanized or thermoplastic — Determination of tensile stress-strain properties," the polyurethane materials obtained in each Example and Comparative Example were cut into Type 1 dumbbell-shaped specimens. The tensile strength TS0 of each test specimen was tested at room temperature (23±2°C). The test specimens were then placed in a temperature and humidity alternating test chamber at 70±2°C and a relative humidity of 95% or higher for 168 hours. After removal, the tensile strength TS1 after wet aging was measured, and the tensile strength retention after wet aging was calculated as δ = TS1 / TS0 × 100%. The results are shown in Table 1.

[0169] Table 1

[0170] <![CDATA[TS0(MPa)]]> <![CDATA[TS1(MPa)]]> δ(%) Example 2-1 28.6 26.3 91.96 Example 2-2 27.4 24.7 90.15 Example 2-3 29.3 27.5 93.86 Examples 2-4 27.9 25.4 91.04 Examples 2-5 27.3 25.4 93.04 Examples 2-6 28.2 26.2 92.91 Examples 2-7 29.7 28.2 94.95 Examples 2-8 24.4 19.8 81.15 Examples 2-9 25.3 21.0 83.00 Comparative Example 2-1 20.6 15.6 76.21 Comparative Example 2-2 18.9 13.0 68.78 Comparative Examples 2-3 16.5 12.2 73.94

[0171] According to Table 1, the tensile strength and the tensile strength retention rate after wet aging of the polyurethane materials of each embodiment are significantly higher than those of each comparative example, indicating that the polydimethylsiloxane poly ɛ-caprolactone block polymer diol provided by the present application can effectively improve the mechanical properties and durability of the polyurethane material. Specifically, in Comparative Example 2-1, the oligomer diol uses the polydimethylsiloxane poly ɛ-caprolactone block polymer diol prepared in Comparative Example 1-1. Although the polydimethylsiloxane ends thereof have poly ɛ-caprolactone segments by chemical grafting, the length of the polydimethylsiloxane segments is too long, and the interfacial compatibility between the soft segments is poor, resulting in poor mechanical properties and durability; in Comparative Example 2-2, the oligomer diol uses poly ɛ-caprolactone diol, and no polydimethylsiloxane soft segments are introduced into the polyurethane material. Its mechanical properties are poor, and the polyester segment has poor stability under high temperature and high humidity. At the same time, it lacks the more flexible and hydrophobic polydimethylsiloxane segment, resulting in a lack of flexible buffering and hydrophobic protection when the material is eroded by moisture in a high humidity environment, microcracks are easily formed, and the mechanical properties and durability are significantly reduced; in Comparative Examples 2-3, although polyɛ-caprolactone diol and dihydroxy-terminated polydimethylsiloxane are physically mixed in the formula, due to the lack of chemical grafting and orderly molecular integration between the two, the interface compatibility is insufficient, and the mechanical properties and durability are poor.

[0172] According to Examples 2-1 to 2-7, by using different polydimethylsiloxane polyɛ-caprolactone block polymer diols, the tensile strength and strength retention rate after wet aging of the obtained polyurethane materials are both high, indicating that the block polyol can achieve efficient integration of polydimethylsiloxane segments and polyɛ-caprolactone segments at the molecular level, significantly improve the compatibility and interfacial continuity within the soft segment, reduce interfacial microphase separation and performance degradation in high humidity environments, and give the material better durability.

[0173] Examples 2-1, 2-8, and 2-9 demonstrate that, while maintaining the same primary polyol system, the presence or absence of an imidazole-based silane coupling agent significantly impacts the mechanical properties and durability of the polyurethane material. The introduction of an imidazole-based silane coupling agent in Example 2-1 resulted in a polyurethane material with significantly better mechanical properties and durability than those in Example 2-8 (without a silane coupling agent) and Example 2-9 (with an aminosilane coupling agent). This further demonstrates that the amphiphilic bridging effect of the imidazole-based silane coupling agent effectively enhances the interfacial bonding and compatibility of the polyurethane material system (including between the soft and hard segments, and between the polydimethylsiloxane and poly-ɛ-caprolactone segments within the soft segments), reduces microphase separation and performance degradation in high-humidity environments, and thus improves the mechanical properties and durability of the polyurethane material.

[0174] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing polydimethylsiloxane poly-ɛ-caprolactone block polymer diol, characterized in that: The following steps are involved: S1: reacting a diol and ɛ-caprolactone under the catalysis of a first catalyst to cause the ɛ-caprolactone to ring-open and react with the hydroxyl group of the diol to obtain a poly ɛ-caprolactone diol; wherein the relative molecular mass of the diol is less than 150; and the molar ratio of the diol to the ɛ-caprolactone is 1:(2-6); S2: reacting poly-ɛ-caprolactone diol and halogenated olefin under the catalysis of a second catalyst, so that olefin groups are substituted and grafted onto both ends of the poly-ɛ-caprolactone diol to obtain double-terminal olefin-based poly-ɛ-caprolactone; S3: reacting a dipolefin-terminated polyɛ-caprolactone with a dipolefin-terminated hydrogenated polydimethylsiloxane under the catalysis of a third catalyst, so that the dipolefin-terminated hydrogenated polydimethylsiloxane is grafted onto both ends of the dipolefin-terminated polyɛ-caprolactone to obtain a dipolefin-terminated hydrogenated polydimethylsiloxane-grafted polyɛ-caprolactone; wherein the dipolefin-terminated polyɛ-caprolactone has a number average molecular weight of 200 to 1000; and the dipolefin-terminated hydrogenated polydimethylsiloxane has a number average molecular weight of 300 to 1000; S4: reacting the double-end hydrogenated polydimethylsiloxane grafted polyɛ-caprolactone with an enol compound under the catalysis of a fourth catalyst, so that both ends of the double-end hydrogenated polydimethylsiloxane grafted polyɛ-caprolactone are addition-grafted with the enol compound to obtain a polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane block polymer diol; S5: reacting polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane block polymer diol with ɛ-caprolactone under the catalysis of a fifth catalyst, so that the ɛ-caprolactone is ring-opened and reacts with the hydroxyl group of the polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane block polymer diol to obtain polyɛ-caprolactone-polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane-polyɛ-caprolactone block polymer diol as the polydimethylsiloxane-polyɛ-caprolactone block polymer diol; wherein the molar ratio of the polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane block polymer diol to the ɛ-caprolactone is 1:(2~6).

2. The method according to claim 1, characterized in that The step S1 satisfies at least one of the following conditions: 1) The first catalyst includes an organic tin catalyst, and the amount of the first catalyst added is 0.1% to 0.5% of the total mass of the diol and ɛ-caprolactone; 2) The reaction conditions include: reacting at 110-150° C. for 8-12 hours.

3. The method according to claim 1, characterized in that The step S2 satisfies at least one of the following conditions: 1) The molar ratio of the poly-ɛ-caprolactone diol to the halogenated olefin is 1:(2.1-2.2); 2) The halogenated olefin includes at least one of allyl chloride, allyl butyl chloride, and allyl bromide; 3) The second catalyst comprises at least one of sodium hydroxide, potassium hydroxide, sodium methoxide, and sodium ethoxide; the molar ratio of the poly-ɛ-caprolactone diol to the second catalyst is 1:(2-2.1); 4) The reaction conditions include: reacting at 100-130° C. for 1-3 hours.

4. The method according to claim 1, wherein Step S3 satisfies at least one of the following conditions: 1) The molar ratio of the double-terminal olefin-based polyɛ-caprolactone to the double-terminal hydrogen-based polydimethylsiloxane is 1:(2.0-2.1); 2) The third catalyst includes a Custer catalyst, and the amount of the third catalyst added is 0.001% to 0.01% of the total mass of the double-terminal olefin-based polyɛ-caprolactone and the double-terminal hydrogen-based polydimethylsiloxane; 3) The reaction conditions include: reacting at 80-150° C. for 2-6 hours.

5. The method according to claim 1, wherein The step S4 satisfies at least one of the following conditions: 1) The molar ratio of the double-terminated hydrogen-polymerized polydimethylsiloxane grafted poly-ɛ-caprolactone to the enol compound is 1:(2.01-2.1); 2) The enol compound includes at least one of allyl alcohol and butanol; 3) The fourth catalyst comprises [1,3-dicyclohexyl-imidazol-2-yl][1,3-divinyl-1,1,3,3,-tetramethyldisiloxane] platinum, and the amount of the fourth catalyst added is 0.001% to 0.005% of the total mass of the double-terminated hydrogen polydimethylsiloxane grafted poly-ɛ-caprolactone and the enol compound; 4) The reaction conditions include: reacting at 80-150° C. for 3-8 hours.

6. The method according to claim 1, characterized in that The step S5 satisfies at least one of the following conditions: 1) The fifth catalyst comprises an organic tin catalyst, and the amount of the fifth catalyst added is 0.1% to 0.5% of the total mass of the polydimethylsiloxane-polyɛ-caprolactone-polydimethylsiloxane block polymer diol and ɛ-caprolactone; 2) The reaction conditions include: reacting at 110-150° C. for 8-12 hours.

7. A polydimethylsiloxane poly-ɛ-caprolactone block polymer diol, characterized in that Prepared according to the method according to any one of claims 1 to 6.

8. A polyurethane material, characterized in that: Including the following raw materials by weight: 100 parts of isocyanate, 80-120 parts of the polydimethylsiloxane poly-ɛ-caprolactone block polymer diol according to claim 7, 10-20 parts of a chain extender, and 0.1-0.5 parts of a catalyst.

9. The polyurethane material according to claim 8, characterized in that The polyurethane material satisfies at least one of the following conditions: 1) The raw materials further include 1 to 5 parts of an imidazole silane coupling agent; 2) The isocyanate includes at least one of diphenylmethane diisocyanate, toluene diisocyanate, p-phenylene diisocyanate, and isophorone diisocyanate; 3) The chain extender includes at least one of ethylene glycol, 1,3-propylene glycol, and 1,3-butanediol; 4) The catalyst includes an organotin catalyst.

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