A high-efficiency polymeric nucleating agent, its preparation method and applications

Abstract

This invention relates to a high-efficiency polymeric nucleating agent, its preparation method, and its uses. The polymeric nucleating agent of this invention comprises a cross-linked polymer, wherein the cross-linked polymer contains structural units derived from photosensitive monomers having dynamic cross-linking groups. The molecular structure of the polymeric nucleating agent of this invention is similar to that of the polymer to be nucleated, and it also contains photosensitive structural units with dynamic cross-linking groups. After the nucleating agent molecules crystallize, they are cross-linked by ultraviolet light irradiation, thereby fixing the topological structure of the crystallized polymer chains. Using this cross-linked polymer as a nucleating agent can significantly improve the crystallization rate. The nucleating agent of this invention possesses both high-efficiency nucleation ability, good dispersibility, and thermal stability.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials, specifically relating to a high-efficiency polymer nucleating agent, its preparation method, and its applications. Background Technology

[0002] Polymer materials, as an indispensable component of modern industry and daily life, have always been a research focus in the field of materials science. Among them, semi-crystalline polymers have attracted widespread attention due to their unique microstructure and excellent comprehensive properties. However, these materials generally suffer from problems such as slow crystallization rate and low crystallinity, which not only affect the final performance of products but also significantly reduce production efficiency, thus restricting their further development in high-performance applications.

[0003] Adding nucleating agents is one of the most effective methods to improve the crystallinity of semi-crystalline polymers. Currently, common nucleating agents are mainly divided into inorganic and organic categories. Inorganic nucleating agents (such as talc, silica, and calcium carbonate) are inexpensive and widely available, but usually require relatively high addition amounts (e.g., 1–5 wt%) to achieve significant effects. However, excessive addition can easily lead to increased material inhomogeneity, affecting mechanical and optical properties. Organic nucleating agents (such as sorbitol derivatives, organophosphates, and benzoates) can improve crystallinity at lower addition amounts (e.g., 0.1–0.5 wt%), but they generally suffer from poor thermal stability and dispersibility, especially under high-temperature processing conditions, where they are prone to decomposition or migration, leading to a weakened nucleation effect.

[0004] In recent years, with the continuous development of nanotechnology and supramolecular chemistry, many nucleating agents based on nanotechnology and supramolecular chemistry (such as nanocellulose, graphene, carbon nanotubes, and supramolecular self-assemblies) have been developed. They have higher specific surface area and nucleation ability, and can significantly improve crystallization performance with extremely low addition amounts. However, due to problems such as complex preparation processes and high costs, their industrial application still faces great challenges.

[0005] In addition, the use of polymers as nucleating agents has also been reported. For example, Patent Document 1 discloses the use of polyvinyl acetal as a macromolecular nucleating agent for polybutylene succinate and its copolyesters. Patent Document 2 discloses a "DBS"-like transparent modified polypropylene macromolecular nucleating agent, which, through reactive processing, co-grafts functional monomers containing key functional groups of "DBS"-like nucleating agents onto the polypropylene molecular chain, thereby constructing a molecular structure of a "DBS"-like nucleating agent grafted onto the polypropylene macromolecular chain segment. The resulting "DBS"-like substituents are polypropylene macromolecular segments, further enhancing the dispersion ability of the nucleating agent in the polypropylene matrix. However, this technology is mainly designed for polypropylene and is difficult to directly apply to other types of semi-crystalline polymer materials, lacking universality. Furthermore, "DBS"-like nucleating agents typically have poor thermal stability and significant hygroscopicity; grafting them onto the polypropylene chain may not solve the stability problem under high-temperature processing conditions. Moreover, the large-scale introduction of grafted structures may alter the properties of polypropylene itself, ultimately adversely affecting the material's mechanical and rheological properties.

[0006] References

[0007] Patent Document 1: CN102492248A;

[0008] Patent document 2: CN117304408A. Summary of the Invention

[0009] The problem the invention aims to solve

[0010] Current technologies lack in-depth research on crystallization mechanisms, making it difficult to achieve precise control of the crystallization process from a molecular perspective.

[0011] The technical problem to be solved by the present invention is to provide a nucleating agent that has both high efficiency in nucleation, good dispersibility and thermal stability.

[0012] Solution for solving the problem

[0013] To address the aforementioned problems, the inventors conducted long-term and in-depth research. Based on their understanding of the polymer crystallization mechanism, they proposed using photosensitive monomers with dynamic crosslinking groups as comonomers to synthesize polymeric nucleating agents, thus completing this invention.

[0014] Specifically, the present invention solves the problems of the present invention through the following solutions.

[0015] [1] A polymeric nucleating agent comprising a crosslinked polymer comprising structural units derived from photosensitive monomers having dynamic crosslinking groups.

[0016] [2] According to the polymeric nucleating agent described in [1], wherein the photosensitive monomer having a dynamic crosslinking group is one or more monomers selected from those having one or more groups of cinnamic acid group, coumarin group, or azophenyl group;

[0017] Preferably, the photosensitive monomer with the dynamic crosslinking group is selected from one or more of N,N-bis(2-hydroxyethyl)cinnamamide, N,N-bis(3-hydroxypropyl)cinnamamide, N,N-bis(2-hydroxyethyl)-4-methoxycinnamamide, N,N-bis(2-hydroxyethyl)-α-methylcinnamamide, N,N-bis(2,3-dihydroxypropyl)cinnamamide, 5,7-dihydroxy-4-methylcoumarin, 6,7-dihydroxy-4-methylcoumarin, 5,7-dihydroxy-4-propylcoumarin, 7,8-dihydroxy-4-methylcoumarin, 7,8-dihydroxy-3,4-dimethylcoumarin, 4,4'-dihydroxyazobenzene, 2,2'-dihydroxyazobenzene, 3,3'-dihydroxyazobenzene, and 4,4'-bis(2-hydroxyethoxy)azobenzene.

[0018] Preferably, the content of the structural units derived from the photosensitive monomer having dynamic crosslinking groups is less than 10 mol%, based on the total number of moles of the structural units of the crosslinked polymer.

[0019] [3] According to the polymeric nucleating agent described in [1] or [2], wherein the crosslinking polymer is selected from at least one of polyester, polyamide, polyolefin, and polyether.

[0020] [4] The method for preparing the polymeric nucleating agent according to any one of [1] to [3] includes the following steps:

[0021] (a) A monomer composition containing a photosensitive monomer having a dynamic crosslinking group is subjected to a polymerization reaction to obtain a precursor polymer;

[0022] (b) Prepare a thin film from the precursor polymer obtained in step (a) and crystallize the precursor polymer;

[0023] (c) The precursor polymer in the film obtained in step (b) is photochemically crosslinked to form the crosslinked polymer.

[0024] [5] According to the preparation method described in [4], the monomer composition comprises one or more selected from diols, dicarboxylic acids, lactones, lactides, compounds containing carboxyl and hydroxyl groups, diamines, compounds containing amino and carboxyl groups, lactams, alkenes, and oxacycloalkanes;

[0025] Preferably, the monomer composition comprises at least one of the following (i) to (ix):

[0026] (i) Diols and dicarboxylic acids,

[0027] (ii) lactone,

[0028] (iii) lactone,

[0029] (iv) Compounds containing carboxyl and hydroxyl groups,

[0030] (v) Dicarboxylic acids and diamines,

[0031] (vi) Compounds containing amino and carboxyl groups,

[0032] (vii) lactam,

[0033] (viii) Alkenes,

[0034] (ix) Oxycyclic alkanes;

[0035] The polymerization reaction in step (a) is carried out by melt polycondensation, coordination polymerization or ring-opening polymerization;

[0036] The number-average molecular weight of the precursor polymer is 1,000 to 100,000 g / mol, preferably 2,000 to 80,000 g / mol.

[0037] [6] According to the preparation method described in [4] or [5], in step (b), the precursor polymer obtained in step (a) is prepared into a thin film by solvent evaporation or hot melt film formation;

[0038] Preferably, the precursor polymer obtained in step (a) is prepared into a thin film by solvent evaporation film formation;

[0039] More preferably, the precursor polymer obtained in step (a) is dissolved in a solvent to obtain a precursor polymer solution, and then the solvent is evaporated to crystallize the precursor polymer and form a thin film; preferably at the glass transition temperature T of the precursor polymer. g To melting point T m The solvent is evaporated within a temperature range between [temperature ranges].

[0040] [7] A composition comprising any one of [1] to [3] a polymeric nucleating agent and a matrix polymer;

[0041] Preferably, the content of the polymeric nucleating agent is 100–50,000 ppm;

[0042] Preferably, the matrix polymer is a semi-crystalline polymer, more preferably selected from at least one of polyester, polyamide, polyolefin, and polyether.

[0043] [8] According to the composition described in [7], the matrix polymer has substantially the same structural unit composition as the crosslinking polymer in the polymeric nucleating agent, except for the structural units derived from the photosensitive monomer having dynamic crosslinking groups.

[0044] [9] Use of crosslinked polymers as polymer nucleating agents, wherein the crosslinked polymers comprise structural units derived from photosensitive monomers having dynamic crosslinking groups;

[0045] Preferably, the polymer is a semi-crystalline polymer, more preferably selected from at least one of polyester, polyamide, polyolefin, and polyether.

[0046]

[10] According to the use described in [9], the polymer has substantially the same structural unit composition as the crosslinked polymer, except for the structural units derived from photosensitive monomers having dynamic crosslinking groups.

[0047] The effects of the invention

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] 1. "Crystallize first, then crosslink" strategy: By introducing dynamic crosslinking groups and carrying out crosslinking reactions, the topological structure of the polymer after crystallization is effectively fixed. The core advantage of this strategy is that even after heating and melting, the polymer chain transforms into an amorphous conformation. However, since the relative positions of the molecular chain segments have been fixed by the crosslinking reaction, the difference between its conformation and that in the crystalline state is still small. This reduces the entropy barrier for crystal nucleation and increases the crystal nucleation rate.

[0050] 2. Excellent dispersibility and interfacial compatibility: The polymeric nucleating agent of the present invention has a similar chemical structure to the matrix polymer, which can significantly improve the dispersibility and interfacial compatibility of the nucleating agent in the polymer matrix, and solve the problems of easy agglomeration and poor interfacial compatibility of traditional inorganic nucleating agents.

[0051] 3. Good thermal stability and migration resistance: Through cross-linking treatment, the present invention endows the nucleating agent with good thermal stability and migration resistance. This cross-linking structure ensures that the nucleating agent remains stable under high temperature processing conditions and effectively inhibits loss and migration during processing, thereby ensuring the durability of the nucleation effect.

[0052] 4. Comprehensively optimized crystallization performance: The polymer nucleating agent prepared by this invention can significantly improve the crystallization rate, crystallization temperature and relative crystallinity of polymers, which can not only improve the overall performance of materials, but also greatly improve production efficiency.

[0053] 5. Wide adaptability: The polymeric nucleating agent of the present invention can be applied to various semi-crystalline polymers, including but not limited to polyesters, polyamides, polyolefins, polyethers, etc.

[0054] 6. Significant cost-effectiveness: The preparation method of the nucleating agent of the present invention requires readily available raw materials and has a simple process, which has significant cost advantages and is conducive to large-scale industrial production. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of the crosslinking of the nucleating agent of the present invention.

[0056] Figure 2 The DSC curves are for the compositions of Example 1 and Comparative Example 1, and for PBS without nucleating agent.

[0057] Figure 3 The DSC curves are for the compositions of Example 2 and Comparative Example 2, and for PLLA without nucleating agent. Detailed Implementation

[0058] The present invention will now be described in detail. The description of the technical features described below is based on representative embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples.

[0059] <Terminology and Definitions>

[0060] In this specification, "polymer" and "high molecular weight polymer" have the same meaning.

[0061] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0062] In this specification, the numerical range indicated by "above" or "below" refers to the numerical range that includes the stated number.

[0063] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0064] In this specification, the terms "optionally" or "optionally" are used to indicate the use or non-use of certain substances, components, procedures, application conditions, etc.

[0065] All unit names used in this manual are international standard unit names, and unless otherwise stated, the "%" used refers to weight or mass percentage content.

[0066] In this specification, references to "preferred embodiments," "implementation methods," etc., mean that a specific element (e.g., feature, structure, property, and / or characteristic) related to that embodiment is included in at least one of the embodiments described herein, and may or may not be present in other embodiments. Furthermore, it should be understood that the elements may be combined in any suitable manner in various embodiments.

[0067] <Polymer nucleating agents and their preparation methods>

[0068] One object of the present invention is to provide a polymeric nucleating agent comprising a crosslinked polymer, said crosslinked polymer comprising structural units derived from photosensitive monomers having dynamic crosslinking groups.

[0069] Among them, "structural unit derived from photosensitive monomer with dynamic cross-linking group" refers to a structural unit formed by the polymerization reaction of photosensitive monomer with dynamic cross-linking group, which can also be called "photosensitive structural unit with dynamic cross-linking group".

[0070] This invention uses photosensitive monomers with dynamic crosslinking groups to impart dynamic crosslinking properties to crosslinked polymers. Furthermore, the molecular chain topology (e.g., folded conformation) corresponding to the crystalline state can be easily fixed through photochemical crosslinking reactions, thereby reducing the activation energy of the nucleation process and improving the nucleation efficiency of polymer crystallization.

[0071] Preferably, the photosensitive monomer having a dynamic crosslinking group is one or more monomers selected from those having one or more groups of cinnamic acid group, coumarin group, or azophenyl group.

[0072] Monomers containing cinnamic acid groups include N,N-bis(2-hydroxyethyl)cinnamamide (BHECA), N,N-bis(2-hydroxyethyl)cinnamamide, N,N-bis(3-hydroxypropyl)cinnamamide, N,N-bis(2-hydroxyethyl)-4-methoxycinnamamide, N,N-bis(2-hydroxyethyl)-α-methylcinnamamide, and N,N-bis(2,3-dihydroxypropyl)cinnamamide.

[0073] Monomers containing a coumarin group include 5,7-dihydroxy-4-methylcoumarin, 6,7-dihydroxy-4-methylcoumarin, 5,7-dihydroxy-4-propylcoumarin, 7,8-dihydroxy-4-methylcoumarin, and 7,8-dihydroxy-3,4-dimethylcoumarin.

[0074] Monomers containing an azophenyl group include 4,4'-dihydroxyazobenzene, 2,2'-dihydroxyazobenzene, 3,3'-dihydroxyazobenzene, and 4,4'-bis(2-hydroxyethoxy)azobenzene.

[0075] In some implementations, structural units derived from photosensitive monomers with dynamically crosslinking groups are located on the backbone of the crosslinked polymer. In this document, the backbone of the crosslinked polymer refers to its backbone in its uncrosslinked state.

[0076] In some implementations, the dynamically crosslinked groups in the crosslinked polymer are in a crosslinked state.

[0077] In some implementations, the crosslinked polymer contains only crosslinked structures formed by dynamically crosslinking groups.

[0078] Preferably, based on the total molar number of structural units of the crosslinked polymer, the content of the structural units derived from the photosensitive monomer having dynamic crosslinking groups is 10 mol% or less, preferably 8 mol% or less, more preferably 6 mol% or less, even more preferably 4 mol% or less, and even more preferably 2 mol% or less. The present invention does not particularly limit the lower limit of the content of structural units derived from the photosensitive monomer having dynamic crosslinking groups; for example, it can be 0.01 mol% or more, preferably 0.1 mol% or more, even more preferably 0.2 mol% or more, and more preferably 0.3 mol% or more. Examples include 0.4 mol%, 0.5 mol%, 0.6 mol%, 0.7 mol%, 0.8 mol%, 0.9 mol%, 1 mol%, and 1.5 mol%.

[0079] Preferably, the crosslinked polymer is selected from at least one of polyester, polyamide, polyolefin, and polyether. Here, the term "polymer type" refers to a crosslinked polymer containing structural units that form the described polymer type, and the proportion of these structural units in the total structural units is preferably 80 mol% or more, more preferably 90 mol% or more. For example, when the crosslinked polymer is a polyester, it contains structural units that form polyester, i.e., monomers derived from diols, dicarboxylic acids, etc.

[0080] Polyesters can be aliphatic polyesters or aromatic polyesters, such as polymers obtained by condensation polymerization of diols and dicarboxylic acids, polymers obtained by ring-opening polymerization of lactones or lactides, and polymers obtained by condensation polymerization of compounds containing carboxyl and hydroxyl groups.

[0081] Diols include, but are not limited to, aliphatic diols with 2 to 20 carbon atoms and aromatic diols with 6 to 20 carbon atoms, such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,4-benzenedimethanol, 1,4-benzenediethanol, 1,4-benzenedipropanol, 1,3-benzenedimethanol, 1,3-benzenediethanol, 1,3-benzenedipropanol, etc., and derivatives of these diols substituted with one or more substituents, wherein the substituents may be F, Cl, Br, CN, C, etc. 1～6 Alkyl groups, etc.

[0082] Dicarboxylic acids include, but are not limited to, aliphatic dicarboxylic acids with 3 to 20 carbon atoms and aromatic dicarboxylic acids with 8 to 20 carbon atoms, such as malonic acid, succinic acid, 1,5-glutaric acid, 1,6-adipic acid, 1,7-heptanedic acid, 1,8-octanoic acid, 1,9-azelaic acid, 1,10-sebacic acid, terephthalic acid, isophthalic acid, etc., as well as derivatives of these dicarboxylic acids substituted with one or more substituents, wherein the substituents may be F, Cl, Br, CN, C. 1～6 Alkyl groups, etc.

[0083] Lactones include, but are not limited to, aliphatic lactones with 4 to 10 carbon atoms, such as caprolactone and valproic acid lactone.

[0084] Lactose includes, but is not limited to, glycolide and lactide.

[0085] Compounds containing carboxyl and hydroxyl groups include, but are not limited to, lactic acid and β-hydroxybutyric acid.

[0086] Examples of polyesters include polybutylene succinate (PBS), polybutylene fumarate (PBF), polybutylene adipate (PBA), polycaprolactone (PCL), polyhydroxybutyrate (PHB), polyhydroxyvalerate (PHV), polyethylene succinate (PES), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polylactic acid (PLA), and polybutylene terephthalate-adipate (PBAT).

[0087] Polyamides can be aliphatic polyamides and aromatic polyamides. Examples include polymers obtained by polycondensation of dicarboxylic acids and diamines, polymers obtained by polycondensation of compounds containing amino and carboxyl groups, and polymers obtained by ring-opening polymerization of lactams. The dicarboxylic acid can be any of the dicarboxylic acids described above. The diamine can be an aliphatic diamine with 2 to 20 carbon atoms or an aromatic diamine with 6 to 20 carbon atoms, such as ethylenediamine, propylenediamine, 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, p-phenylenediamine, m-phenylenediamine, etc., and derivatives of these diamines substituted with one or more substituents, wherein the substituents can be F, Cl, Br, CN, C. 1～6 Alkyl groups, etc. Compounds containing amino and carboxyl groups, such as 6-aminohexanoic acid, 12-aminododecanoic acid, etc. Lactams, such as ε-caprolactam, ω-dodecanoic acid, etc.

[0088] Examples of polyamides include polyamide 6 (Nylon 6), polyamide 66 (Nylon 66), polyamide 46, polyamide 12, polyamide 69, and polyamide 6-10.

[0089] Polyolefins can be polymers obtained by polymerizing olefins, such as olefins having 2 to 20 carbon atoms, such as ethylene, propylene, butene, pentene, hexene, octene, styrene, etc., and derivatives of these olefins substituted with one or more substituents, such as F, Cl, Br, CN, C. 1～6 Alkyl groups, etc.

[0090] Polyolefins can be listed as one or more of polyethylene (PE), polypropylene (PP), and polystyrene (PS).

[0091] Polyethers can be polymers obtained by polymerizing oxacycloalkanes, such as ethylene oxide, propylene oxide, oxacyclobutane, and tetrahydrofuran.

[0092] Examples of polyethers include polyethylene oxide, polypropylene oxide, polyoxyethylene butane, and polytetrahydrofuran.

[0093] One object of the present invention is to provide a method for preparing a polymeric nucleating agent, characterized by comprising the following steps:

[0094] (a) A monomer composition containing a photosensitive monomer having a dynamic crosslinking group is subjected to a polymerization reaction to obtain a precursor polymer;

[0095] (b) Prepare a thin film from the precursor polymer obtained in step (a) and crystallize the precursor polymer;

[0096] (c) The precursor polymer in the film obtained in step (b) is photochemically crosslinked to form the crosslinked polymer.

[0097] The following describes each step of the preparation method of the present invention.

[0098] Step (a)

[0099] In step (a), a monomer composition containing a photosensitive monomer with a dynamic crosslinking group is subjected to a polymerization reaction to obtain a precursor polymer.

[0100] The photosensitive monomers with dynamic cross-linking groups are as described above.

[0101] Preferably, the monomer composition further includes other monomers forming the crosslinked polymer, including but not limited to one or more selected from diols, dicarboxylic acids, lactones, lactides, compounds containing carboxyl and hydroxyl groups, diamines, compounds containing amino and carboxyl groups, lactams, alkenes, and oxacycloalkanes.

[0102] Preferably, the monomer composition comprises at least one of the following monomers or combinations thereof (i) to (ix):

[0103] (i) Diols and dicarboxylic acids,

[0104] (ii) lactone,

[0105] (iii) lactone,

[0106] (iv) Compounds containing carboxyl and hydroxyl groups,

[0107] (v) Dicarboxylic acids and diamines,

[0108] (vi) Compounds containing amino and carboxyl groups,

[0109] (vii) lactam,

[0110] (viii) Alkenes,

[0111] (ix) Oxycyclic alkanes.

[0112] When the crosslinking polymer is polyester, the monomer composition includes at least one of the monomers or combinations thereof described in (i) to (iv).

[0113] When the crosslinked polymer is a polyamide, the monomer composition comprises at least one of the monomers or combinations thereof described in (v) to (vii).

[0114] When the crosslinked polymer is a polyolefin, the monomer composition contains one or more (viii) olefins.

[0115] When the crosslinked polymer is a polyether, the monomer composition contains (ix) oxocyclic alkanes.

[0116] Among them, diols, dicarboxylic acids, lactones, lactides, compounds containing carboxyl and hydroxyl groups, diamines, compounds containing amino and carboxyl groups, lactams, alkenes, and oxacycloalkanes can be those described above.

[0117] Preferably, the content of the photosensitive monomer having dynamically crosslinked groups in the monomer composition is 10 mol% or less, more preferably 8 mol% or less, more preferably 6 mol% or less, even more preferably 4 mol% or less, and even more preferably 2 mol% or less. The present invention does not particularly limit the lower limit of the content of the photosensitive monomer having dynamically crosslinked groups; for example, it can be 0.01 mol% or more, preferably 0.1 mol% or more, even more preferably 0.2 mol% or more, and more preferably 0.3 mol% or more. Examples include 0.4 mol%, 0.5 mol%, 0.6 mol%, 0.7 mol%, 0.8 mol%, 0.9 mol%, 1 mol%, and 1.5 mol%.

[0118] The present invention does not impose any particular limitation on the method for carrying out the polymerization reaction in step (a). For example, it can be a conventional polymerization method in the art, such as melt polycondensation, coordination polymerization, or ring-opening polymerization. In particular, those skilled in the art can select a suitable polymerization method according to the type of crosslinked polymer. For example, when the crosslinked polymer is polyester or polyamide, melt polycondensation can be used; when the crosslinked polymer is polyolefin, coordination polymerization can be used; and when the crosslinked polymer is polyether, ring-opening polymerization can be used.

[0119] The polymerization reaction in step (a) can be carried out under conditions conventional in the art. For example, the polymerization temperature can be 40–260°C; the polymerization time can be 1–8 h. Specifically, in the case of melt polycondensation, the reaction temperature is 150–260°C and the reaction time is 2–8 h; in the case of coordination polymerization, the reaction temperature is 180–200°C and the reaction time is 1–4 h; in the case of ring-opening polymerization, the reaction temperature is 40–120°C and the reaction time is 1–8 h.

[0120] The number-average molecular weight of the polymer obtained in step (a) is 1,000 to 100,000 g / mol, preferably 2,000 to 80,000 g / mol.

[0121] Step (b)

[0122] In step (b), the precursor polymer obtained in step (a) is prepared into a thin film and the precursor polymer is crystallized.

[0123] Preferably, in step (b), the precursor polymer obtained in step (a) is prepared into a thin film by solvent evaporation or thermal melting.

[0124] In some embodiments, the precursor polymer obtained in step (a) is prepared into a film and crystallized using a thermal melt film-forming method. Specifically, the precursor polymer can be melted by heating, then formed into a film (e.g., by extrusion), and then crystallized by cooling.

[0125] The present invention does not impose any particular limitation on the melting temperature, and a temperature higher than the melting point can be selected depending on the type of precursor polymer. As for the cooling temperature, it can be based on the glass transition temperature T of the precursor polymer. g To melting point T m The temperature range between (T) g ~T m ).

[0126] In a preferred embodiment, the precursor polymer obtained in step (a) is prepared into a thin film by solvent evaporation. Specifically, the precursor polymer obtained in step (a) is dissolved in a solvent to obtain a precursor polymer solution, the precursor polymer solution is coated into a film, and then the solvent is evaporated to allow the precursor polymer to crystallize and form a thin film.

[0127] The solvent can be an organic solvent or water. The organic solvent is preferably one or more selected from hydrocarbons, halogenated hydrocarbons, ethers, esters, ketones, amides, sulfoxides, and nitriles. More preferably, it is one or more selected from chloroform, dichloromethane, tetrachloroethane, tetrahydrofuran, N,N-dimethylformamide, o-dichlorobenzene, toluene, xylene, trichloroethylene, tetrachloroethylene, ethyl acetate, acetone, cyclohexanone, dimethyl sulfoxide, n-hexane, acetonitrile, cyclohexane, and dimethylacetamide.

[0128] Preferably, the content of the precursor polymer in the precursor polymer solution is 0.1 to 10% by mass, more preferably 0.2 to 8% by mass, more preferably 0.3 to 6% by mass, even more preferably 0.4 to 4% by mass, and also, for example, 0.5 to 3% by mass, 0.6 to 2% by mass, etc.

[0129] Preferably, the precursor polymer is dissolved in the solvent under stirring conditions, and the stirring time is preferably 0.5 to 5 hours, more preferably 0.5 to 4 hours, and even more preferably 1 to 3 hours.

[0130] The present invention does not impose any particular limitation on the method of coating the precursor polymer solution into a film, such as spin coating, spraying, printing, casting, etc.

[0131] Preferably, the glass transition temperature T of the precursor polymer is... g To melting point T m Within the temperature range between (T) g ~T m The solvent is evaporated while the polymer crystallizes simultaneously. For example, the solvent evaporation temperature can be 40–100°C, preferably 40–80°C.

[0132] Preferably, the solvent evaporation time can be 1 to 10 hours, more preferably 2 to 8 hours, and even more preferably 3 to 7 hours.

[0133] Step (c)

[0134] In step (c), the precursor polymer in the film obtained in step (b) is photochemically crosslinked to form the crosslinked polymer.

[0135] Preferably, the precursor polymer therein undergoes a photochemical crosslinking reaction by irradiating the film obtained in step (b).

[0136] More preferably, the light irradiation is performed using ultraviolet light, and the wavelength of the ultraviolet light is preferably 200-400 nm, for example 365 nm.

[0137] More preferably, the light irradiation time is 0.1 to 5 hours, and more preferably 0.5 to 3 hours.

[0138] Other steps

[0139] In some embodiments, the method of the present invention further includes the step of preparing a photosensitive monomer having dynamically crosslinked groups.

[0140] For example, monomers with cinnamamide groups can be prepared by transesterification of cinnamate with diethanolamines (e.g., diethanolamine, dipropanolamine, etc.). The transesterification reaction can be carried out under suitable conditions known in the art, such as in a vacuum, under heating (e.g., 80–120 °C), and in the presence of a catalyst (e.g., sodium alkoxide, sodium carbonate, tetrabutyl titanate).

[0141] In some embodiments, the preparation method of the present invention further includes other steps such as cutting and crushing the crosslinked film obtained in step (c).

[0142] <Composition>

[0143] One object of the present invention is to provide a composition comprising the polymeric nucleating agent and the matrix polymer of the present invention.

[0144] Preferably, the mass content of the polymeric nucleating agent in the composition of the present invention is 100 to 50,000 ppm, more preferably 1,000 to 20,000 ppm, and even more preferably 2,000 to 10,000 ppm. Maintaining the content of the polymeric nucleating agent within the above range is beneficial for improving the crystallization properties of the composition.

[0145] The matrix polymer is preferably a semi-crystalline polymer, such as at least one selected from polyester, polyamide, polyolefin, and polyether.

[0146] Polyesters can be aliphatic polyesters or aromatic polyesters, such as polymers obtained by condensation polymerization of diols and dicarboxylic acids, polymers obtained by ring-opening polymerization of lactones or lactides, and polymers obtained by condensation polymerization of compounds containing carboxyl and hydroxyl groups.

[0147] Diols include, but are not limited to, aliphatic diols with 2 to 20 carbon atoms and aromatic diols with 6 to 20 carbon atoms, such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,4-benzenedimethanol, 1,4-benzenediethanol, 1,4-benzenedipropanol, 1,3-benzenedimethanol, 1,3-benzenediethanol, 1,3-benzenedipropanol, etc., and derivatives of these diols substituted with one or more substituents, wherein the substituents may be F, Cl, Br, CN, C, etc. 1～6 Alkyl groups, etc.

[0148] Dicarboxylic acids include, but are not limited to, aliphatic dicarboxylic acids with 3 to 20 carbon atoms and aromatic dicarboxylic acids with 8 to 20 carbon atoms, such as malonic acid, succinic acid, 1,5-glutaric acid, 1,6-adipic acid, 1,7-heptanedic acid, 1,8-octanoic acid, 1,9-azelaic acid, 1,10-sebacic acid, terephthalic acid, isophthalic acid, etc., as well as derivatives of these dicarboxylic acids substituted with one or more substituents, wherein the substituents may be F, Cl, Br, CN, C. 1～6 Alkyl groups, etc.

[0149] Lactones include, but are not limited to, aliphatic lactones with 4 to 10 carbon atoms, such as caprolactone and valproic acid lactone.

[0150] Lactose includes, but is not limited to, glycolide and lactide.

[0151] Compounds containing carboxyl and hydroxyl groups include, but are not limited to, lactic acid and β-hydroxybutyric acid.

[0152] Examples of polyesters include polybutylene succinate (PBS), polybutylene fumarate (PBF), polybutylene adipate (PBA), polycaprolactone (PCL), polyhydroxybutyrate (PHB), polyhydroxyvalerate (PHV), polyethylene succinate (PES), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polylactic acid (PLA), and polybutylene terephthalate-adipate (PBAT).

[0153] Polyamides can be aliphatic polyamides and aromatic polyamides. Examples include polymers obtained by polycondensation of dicarboxylic acids and diamines, polymers obtained by polycondensation of compounds containing amino and carboxyl groups, and polymers obtained by ring-opening polymerization of lactams. The dicarboxylic acid can be any of the dicarboxylic acids described above. The diamine can be an aliphatic diamine with 2 to 20 carbon atoms or an aromatic diamine with 6 to 20 carbon atoms, such as ethylenediamine, propylenediamine, 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, and derivatives of these diamines substituted with one or more substituents, where the substituents can be F, Cl, Br, CN, or C. 1～6 Alkyl groups, etc. Compounds containing amino and carboxyl groups, such as 6-aminohexanoic acid, 12-aminododecanoic acid, etc. Lactams, such as ε-caprolactam, ω-dodecanoic acid, etc.

[0154] Examples of polyamides include polyamide 6 (Nylon 6), polyamide 66 (Nylon 66), polyamide 46, polyamide 12, polyamide 69, and polyamide 6-10.

[0155] Polyolefins can be polymers obtained by polymerizing olefins, such as olefins having 2 to 20 carbon atoms, such as ethylene, propylene, butene, pentene, hexene, octene, styrene, etc., and derivatives of these olefins substituted with one or more substituents, such as F, Cl, Br, CN, C. 1～6 Alkyl groups, etc.

[0156] Polyolefins can be listed as one or more of polyethylene (PE), polypropylene (PP), and polystyrene (PS).

[0157] Polyethers can be polymers obtained by polymerizing oxacycloalkanes, such as ethylene oxide, propylene oxide, oxacyclobutane, and tetrahydrofuran.

[0158] Examples of polyethers include polyethylene oxide, polypropylene oxide, polyoxyethylene butane, and polytetrahydrofuran.

[0159] Preferably, the content of the matrix polymer in the composition of the present invention is 80% by mass or more, more preferably 90% by mass or more, more preferably 95% by mass or more, even more preferably 97% by mass or more, and also preferably 98% by mass or more, such as 99% by mass, 99.2% by mass, 99.4% by mass, 99.6% by mass, 99.8% by mass, etc.

[0160] Preferably, the matrix polymer and the crosslinking polymer in the polymeric nucleating agent are the same type of polymer, such as polyester, polyamide, polyolefin or polyether.

[0161] More preferably, apart from the structural units derived from the photosensitive monomers having dynamic crosslinking groups, the matrix polymer and the crosslinked polymer in the polymeric nucleating agent have substantially the same structural unit composition. Here, "substantially the same" means 90 mol% or more, preferably 95 mol% or more, more preferably 98 mol% or more, and even more preferably 99 mol% or more, for example, 100 mol% the same.

[0162] The compositions of the present invention can be prepared by conventional methods in the art, such as melt blending or solvent blending of the polymeric nucleating agent of the present invention with a matrix polymer.

[0163] <Applications>

[0164] One object of the present invention is to provide the use of crosslinked polymers as polymer nucleating agents, wherein the crosslinked polymer comprises structural units derived from photosensitive monomers having dynamic crosslinking groups.

[0165] For a description of crosslinked polymers, please refer to the above text.

[0166] The polymer is preferably a semi-crystalline polymer, such as at least one selected from polyester, polyamide, polyolefin, and polyether. For a description of the polymer, please refer to the description of the matrix polymer above.

[0167] Preferably, the polymer has substantially the same structural unit composition as the crosslinked polymer, except for the structural units derived from photosensitive monomers with dynamic crosslinking groups. "Substantially the same" means 90 mol% or more, preferably 95 mol% or more, more preferably 98 mol% or more, and even more preferably 99 mol% or more, for example, 100 mol% identical.

[0168] Example

[0169] The following specific embodiments further illustrate the present invention. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the contents of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by this invention.

[0170] Example 1

[0171] Preparation of Polymer Nucleating Agents

[0172] (1) Synthesis of N,N-bis(2-hydroxyethyl)cinnamamide containing photosensitive groups: 8.11 g methyl cinnamate and 10.51 g diethanolamine were added to a 100 mL flask. The mixture was heated to 110 °C with stirring, and then 0.05 g sodium methoxide was added. The reaction was continued for 2 hours under vacuum. The mixture was precipitated with a mixture of 150 mL ice water and 0.1 mL hydrochloric acid. Finally, it was recrystallized in ethyl acetate to obtain a white powder. The powder was dried under vacuum at 80 °C for 48 hours to obtain N,N-bis(2-hydroxyethyl)cinnamamide (BHECA).

[0173] (2) The dried BHECA (0.5 mol%) obtained in step (1) was used as the third comonomer and reacted with 1,4-butanediol (49.5 mol%) and succinic acid (50 mol%) to prepare the copolymer PBS-co-BHECA through multi-step melt polycondensation. The polymerization reaction temperature was controlled at 215℃, the reaction time was controlled at 5 hours, and the final molecular weight was 7500 g / mol.

[0174] (3) Dissolve 0.1g of PBS-co-BHECA obtained in step (2) in 10ml of chloroform to prepare a 1wt% solution and stir for 2 hours;

[0175] (4) Pour the solution from step (3) into a petri dish and place it on a hot plate at 65°C for 4 hours to allow the solvent to evaporate and crystallize completely to form a thin film;

[0176] (5) The film obtained in step (4) is photocrosslinked under 365nm ultraviolet light for 2 hours to obtain the final polymer nucleating agent.

[0177] <Preparation of the Composition>

[0178] (6) Add the polymeric nucleating agent obtained in step (5) to PBS at a ratio of 0.5 wt% to obtain a mixture;

[0179] (7) Dissolve 0.1g of the mixture obtained in (6) above in 10ml of chloroform (1wt%), stir for 2 hours, and then place the solution on a hot plate at 65°C to allow the solvent to evaporate, thus preparing the PBS / nucleating agent composition.

[0180] Example 2

[0181] Preparation of Polymer Nucleating Agents

[0182] (1) N,N-bis(2-hydroxyethyl)cinnamamide containing a photosensitive group was synthesized in the same manner as step (1) in Example 1;

[0183] (2) The dried BHECA obtained in step (1) was used as an initiator (0.1 mol%) to initiate the ring-opening polymerization of L-lactide (99.9 mol%) to prepare linear PLLA-BHECA. The polymerization reaction temperature was controlled at 170℃ and the reaction time was controlled at 3 hours. The final molecular weight was 30000 g / mol.

[0184] (3) Dissolve 0.1g of PLLA-BHECA obtained in step (2) in 10ml of chloroform to prepare a 1wt% solution and stir for 2 hours;

[0185] (4) Pour the solution from step (3) into a petri dish and place it on a hot plate at 40°C for 10 hours to allow the solvent to evaporate and crystallize fully to form a thin film;

[0186] (5) The film obtained in step (4) is photocrosslinked under 365nm ultraviolet light for 2 hours to obtain a polymer nucleating agent.

[0187] <Preparation of the Composition>

[0188] (6) Add the polymeric nucleating agent obtained in step (5) to PLLA at a ratio of 0.5 wt% to obtain a mixture;

[0189] (7) Dissolve 0.1g of the mixture obtained in (6) above in 10ml of chloroform (1wt%), stir for 2 hours, and then place the solution on a hot table at 65°C to allow the solvent to evaporate, thus preparing the PLLA / nucleating agent composition.

[0190] Comparative Example 1

[0191] Following the same procedure as steps (6) and (7) in Example 1, the untreated precursor polymer PBS-co-BHECA obtained in step (2) of Example 1 was added to PBS at a ratio of 0.5 wt% to prepare the composition.

[0192] Comparative Example 2

[0193] Following the same procedure as steps (6) and (7) in Example 2, the untreated precursor polymer PLLA-BHECA obtained in step (2) of Example 2 was added to PLLA at a ratio of 0.5 wt% to prepare the composition.

[0194] <Evaluation>

[0195] The crystallization behavior of PBS, PLLA, and the compositions obtained in Examples 1, 2, 1, and 2 (without nucleating agents) was tested by differential scanning calorimetry (DSC). For PBS, Comparative Example 1, and Example 1 (without nucleating agents), the temperature was raised to 160°C at a constant rate, then cooled, and then raised again. Curves for the first cooling (a) and second heating (b) were collected at a heating / cooling rate of 10°C / min. For PLLA, Comparative Example 2, and Example 2 (without nucleating agents), the temperature was raised to 210°C at a constant rate, then cooled, and then raised again. Curves for the first cooling (a) and second heating (b) were collected at a heating / cooling rate of 10°C / min. The results are shown in Tables 1 and 2, and the DSC curves are as follows: Figure 2 and 3 As shown.

[0196] Crystallinity (X) in Tables 1 and 2 c It is calculated using the following formula:

[0197]

[0198] Where, ΔH m ΔH is the enthalpy of fusion. cc It is the enthalpy of cold crystallization; The standard melting enthalpy is 133.5 J / g and 93.0 J / g for PBS and PLLA, respectively.

[0199] Table 1

[0200]

[0201] From Table 1 and Figure 2 It can be seen that, compared with PBS without nucleating agent, the crystallization temperature of PBS using the polymeric nucleating agent of the present invention is increased by 12.1℃, the relative crystallinity is increased by 11%, and the half-crystallization time of isothermal crystallization at 92℃ is shortened by 88%.

[0202] Table 2

[0203]

[0204] From Table 2 and Figure 3 It can be seen that, compared with PLLA without nucleating agent, the crystallization temperature of PLLA using the polymeric nucleating agent of the present invention is increased by 1.1℃, the cold crystallization temperature is decreased by 11.8℃, and the relative crystallinity is increased by 4.1%.

[0205] Industrial availability

[0206] The polymeric nucleating agent of the present invention can be widely used as a nucleating agent for semi-crystalline polymers.

Claims

1. A method for preparing a polymeric nucleating agent, characterized in that, The polymeric nucleating agent comprises a crosslinked polymer, the crosslinked polymer comprising structural units derived from photosensitive monomers having dynamic crosslinking groups; the dynamic crosslinking groups in the crosslinked polymer are in a crosslinked state; based on the total number of moles of the structural units of the crosslinked polymer, the content of the structural units derived from photosensitive monomers having dynamic crosslinking groups is less than 10 mol% and more than 0.01 mol%. Crosslinked polymers contain only crosslinked structures formed by dynamically crosslinking groups; The preparation method of the polymeric nucleating agent includes the following steps: (a) A monomer composition containing a photosensitive monomer with a dynamic crosslinking group is subjected to a polymerization reaction to obtain a precursor polymer; (b) The precursor polymer obtained in step (a) is prepared into a thin film by solvent evaporation and the precursor polymer is crystallized; (c) The precursor polymer in the film obtained in step (b) is photochemically crosslinked to form the crosslinked polymer; The photosensitive monomer with the dynamic crosslinking group is selected from one or more of N,N-bis(2-hydroxyethyl)cinnamamide, N,N-bis(3-hydroxypropyl)cinnamamide, N,N-bis(2-hydroxyethyl)-4-methoxycinnamamide, N,N-bis(2-hydroxyethyl)-α-methylcinnamamide, N,N-bis(2,3-dihydroxypropyl)cinnamamide, 5,7-dihydroxy-4-methylcoumarin, 6,7-dihydroxy-4-methylcoumarin, 5,7-dihydroxy-4-propylcoumarin, 7,8-dihydroxy-4-methylcoumarin, and 7,8-dihydroxy-3,4-dimethylcoumarin. The monomer composition comprises one or more selected from diols, dicarboxylic acids, lactones, lactides, compounds containing carboxyl and hydroxyl groups, diamines, compounds containing amino and carboxyl groups, and lactams.

2. The preparation method according to claim 1, characterized in that, The polymerization reaction in step (a) is carried out by melt polycondensation; The number-average molecular weight of the precursor polymer is 1,000 to 100,000 g / mol.

3. The preparation method according to claim 1 or 2, characterized in that, The monomer composition comprises at least one of the following (i) to (vii): (i) Diols and dicarboxylic acids, (ii) lactone, (iii) Lactose, (iv) Compounds containing carboxyl and hydroxyl groups, (v) Dicarboxylic acids and diamines, (vi) Compounds containing amino and carboxyl groups, (vii) lactam.

4. The preparation method according to claim 3, characterized in that, The number-average molecular weight of the precursor polymer is 2,000–80,000 g / mol.

5. The preparation method according to claim 1, characterized in that, The precursor polymer obtained in step (a) is dissolved in a solvent to obtain a precursor polymer solution, and then the solvent is evaporated to crystallize the precursor polymer and form a thin film.

6. The preparation method according to claim 5, characterized in that, The glass transition temperature T of the precursor polymer g To melting point T m The solvent is evaporated within a temperature range between [temperature ranges].

7. The preparation method according to claim 1, characterized in that, The crosslinked polymer is selected from at least one of polyester and polyamide.

8. A composition, characterized in that, It includes the polymeric nucleating agent and matrix polymer obtained by the preparation method according to any one of claims 1 to 7.

9. The composition according to claim 8, characterized in that, The content of the polymeric nucleating agent is 100~50000 ppm.

10. The composition according to claim 8, characterized in that, The matrix polymer is a semi-crystalline polymer.

11. The composition according to claim 10, characterized in that, The matrix polymer is selected from at least one of polyester and polyamide.

12. The composition according to claim 8, characterized in that, Apart from the structural units derived from photosensitive monomers with dynamic crosslinking groups, the matrix polymer has essentially the same structural unit composition as the crosslinking polymer in the polymeric nucleating agent.

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