Polyester composition, preparation method thereof and product prepared from polyester composition

Abstract

The invention relates to the field of polymer synthesis, and discloses a polyester composition and a preparation method thereof. The composition comprises a polyester grafted copolymer and a polyester homopolymer, a main chain of the polyester grafted copolymer contains a structural unit A1 shown in a formula (A1), a grafted chain segment of the polyester grafted copolymer is a polyester chain segment, and the average value of the polymerization degree of the grafted chain segment is not less than 150; # imgabs0 # formula (A1), wherein in the formula (A1), the lower corner mark i is any integer not less than 1 and not more than 10; r is independently hydrogen or a C1-C30 organic group, and X is independently a C1-C15 organic group; * represents a connection site and is connected with a grafting chain segment in the polyester grafted copolymer. All the components in the polyester composition have a synergistic effect, so that relatively high viscosity and melt strength as well as relatively high toughness and enough processability can be provided at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer synthesis, in particular to a polyester composition, a preparation method thereof and a product containing the polyester composition. Background Art

[0002] Polyglycolic acid (PGA), also known as polyglycolide or polyglycolic acid, is a fully biodegradable aliphatic polyester polymer that can completely degrade within 1 to 3 months under natural conditions. PGA also exhibits excellent mechanical properties and vapor / oxygen barrier properties, is non-toxic, harmless, and environmentally friendly, making it a safe and biodegradable plastic material.

[0003] On the one hand, polyglycolic acid has poor toughness, with an elongation at break of about 10% and a notched impact strength of less than 3kJ / m 2 On the other hand, the molecular weight of polyglycolic acid obtained by traditional preparation methods is still relatively low, and the melt strength at processing temperature is too low, making it difficult to meet the requirements of applications such as film blowing, foaming, and rod extrusion that require high melt strength. These shortcomings have severely limited the application of polyglycolic acid in these fields.

[0004] CN111647144A (Shanghai Pujing Chemical Technology Co., Ltd.) discloses a method for adjusting the molecular chain structure of polyglycolic acid. The invention mentions that a polyhydroxyl polymer such as polyethylene glycol or starch can be used as an end-capping agent. The polymer is a hydroxylated polymer with characteristic functional group structures such as polyhydroxyl or carboxyl groups or a mixture of hydroxycarboxyl groups (two or more), and a number average molecular weight of 2,000 to 10,000 g / mol. It is also proposed that a molecular weight that is too large will result in steric hindrance and a long reaction time, which will reduce efficiency. SAG (epoxy polymer) or polyethylene glycol is added to the end cap 5 minutes (min) before the end of the reaction, and the final product has a low molecular weight (weight average molecular weight of up to about 200,000 g / mol) and a low intrinsic viscosity of up to about 1.45 dl / g. At the same time, the initiator in this patent document only plays a branching or blocking role. In addition, the polymerization conditions are low-temperature nitrogen protection reaction, the reaction conditions are harsh, and the reaction time is long, at least 50 minutes. The long reaction time will cause thermal decomposition or degradation of PGA to form by-products with color or odor, thereby significantly reducing the quality of PGA products and limiting the scope of application.

[0005] CN112513133A (Shanghai Pujing Chemical Technology Co., Ltd.) relates to a novel polyglycolic acid. In this method, the polyglycolic acid is modified with isocyanate chain extension after polymerization, resulting in a melt strength of 5 to 30 cN at 230°C. However, isocyanate modification is associated with high toxicity, and the biodegradability of the resulting polyglycolic acid is reduced. Furthermore, this method requires post-polymerization modification, resulting in a complex process. Furthermore, this method also requires reaction under low-temperature nitrogen protection, resulting in demanding reaction conditions and a long reaction time, requiring at least 160 minutes.

[0006] In summary, there is a continuous demand in the art for solving the problem that polyglycolic acid has low molecular weight, single molecular weight distribution, and cannot have high melt strength and good processability at the same time, which cannot be met by existing technologies. Summary of the Invention

[0007] The purpose of the present invention is to overcome the problems of polyglycolic acid in the prior art, such as low molecular weight, single molecular weight distribution, and inability to simultaneously have high melt strength and good processability, and to provide a polyester composition and a preparation method thereof. The polyester composition improves melt strength while retaining good processability, and can better meet the application requirements of film blowing, foaming, rod extrusion, etc. that require high melt strength.

[0008] A first aspect of the present invention provides a polyester composition comprising a polyester graft copolymer and a polyester homopolymer, wherein the main chain of the polyester graft copolymer comprises a structural unit A1 represented by formula (A1), the grafted chain segments of the polyester graft copolymer are polyester segments, and the average degree of polymerization of the grafted chain segments is not less than 150;

[0009]

[0010] In formula (A1), the subscript i is an integer not less than 1 and not more than 10; R is independently hydrogen or C1-C 30 Organic group, X is independently C1~C 15 Organic group; * indicates the connection site to which the grafted chain segment in the polyester graft copolymer is connected.

[0011] The second aspect of the invention provides a method for preparing the polyester composition of the first aspect of the invention, comprising melt-polymerizing a polymer raw material containing a macromolecular initiator and a polyester monomer capable of providing a structural polyester chain segment;

[0012] Wherein, the macromolecular initiator contains structural units The definitions of X, R, and i are the same as those in the polyester copolymer described in the first aspect of the present invention.

[0013] The third aspect of the present invention provides a polyester composition prepared by the preparation method of the second aspect of the present invention.

[0014] The fourth aspect of the present invention provides a product, which is made from raw materials comprising the polyester composition of the present invention.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects:

[0016] (1) The various components of the polyester composition of the present invention work synergistically with each other to simultaneously provide high viscosity and melt strength, as well as high toughness and sufficient processing performance (melt fluidity), thereby achieving comprehensive properties that are difficult for single-component polyesters to achieve, and can better meet the application requirements of film blowing, foaming, rod extrusion, etc. that require high melt strength;

[0017] (2) The polyester composition of the present invention can achieve a variety of structural and functional control;

[0018] (3) The preparation method of the present invention uses a macromolecular initiator to initiate the ring-opening polymerization of the monomer when preparing the polyester composition. Compared with not adding the initiator, the reaction efficiency is improved, the reaction time can be greatly reduced, and continuous preparation can be achieved;

[0019] (4) The macromolecular initiator used in the preparation method of the present invention in preparing the polyester composition can obtain a high molecular weight polyester polymer that is difficult to obtain by traditional methods;

[0020] (5) The preparation method of the present invention synthesizes the polyester composition in situ, eliminating the need to prepare polyesters with different molecular weight distributions by melt blending, thereby reducing the inevitable degradation of polyglycolic acid during the blending of different polyesters;

[0021] (6) The initiator in the present invention has a certain solubility in the polyester monomer, which can improve the material premixing efficiency and product uniformity. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is the GPC curve of some embodiments and comparative examples. DETAILED DESCRIPTION

[0023] The endpoints of the ranges and any values disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0024] A first aspect of the present invention provides a polyester composition comprising a polyester graft copolymer and a polyester homopolymer, wherein the main chain of the polyester graft copolymer comprises a structural unit A1 represented by formula (A1), the grafted chain segments of the polyester graft copolymer are polyester segments, and the average degree of polymerization of the grafted chain segments is not less than 150;

[0025]

[0026] In formula (A1), the subscript i is an integer not less than 1 and not more than 10; R is independently hydrogen or C1-C 30 Organic group, X is independently C1~C 15 Organic group; * indicates the connection site to which the grafted chain segment in the polyester graft copolymer is connected.

[0027] In the present invention, in formula (A1), the value of i represents the specific structures of the structural unit A1, that is, when i is greater than 1, the structural unit A1 In the example, it indicates that there are at least two different structural units A11, ... A1i on the structural unit A1. For example, when i is 2, it indicates that there are two different structural units They are represented by A11 and A12 respectively, wherein X and / or R in A11 and A12 are different, and so on.

[0028] The composition of the present invention belongs to polyester polymers, has high melt strength and good processability, and can better meet the application requirements of film blowing, foaming, rod extrusion, etc. that require high melt strength.

[0029] In the present invention, the same symbols in different structural units or segments have the same definition. For example, the subscript i in the present invention represents any integer not less than 1 and not greater than 10.

[0030] According to the present invention, in some preferred embodiments, in formula (A1), X is independently selected from C1 to C 15 Substituted or unsubstituted alkylene, C2~C 15 Substituted or unsubstituted alkyleneoxy or C6~C 15 Substituted or unsubstituted aromatic group. 15 The substituted or unsubstituted alkylene group refers to C1 to C 15 Substituted or unsubstituted alkylene or C2~C 15 substituted or unsubstituted alkenylene, such as substituted or unsubstituted methylene, ethylene, butylene, pentylene, vinylene or 1,4-butadienylene; C2~C 15The substituted or unsubstituted alkyleneoxy group refers to a divalent functional group formed by removing two hydrogen atoms from the carbon of a substituted or unsubstituted alkoxy group containing 2 to 15 carbon atoms, such as methyleneoxy, ethyleneoxy, propyleneoxy or butyleneoxy; C6~C 15 Substituted or unsubstituted aromatic groups refer to divalent functional groups formed by removing two hydrogen atoms from a substituted or unsubstituted aromatic hydrocarbon ring containing 6 to 15 carbon atoms. Aromatic hydrocarbons refer to hydrocarbons with aromatic rings and include monocyclic and polycyclic hydrocarbons, such as 1,3-phenylene, naphthalene diyl, etc.; wherein C1 to C 15 Substituted alkylene, C2~C 15 Substituted alkyleneoxy and C6~C 15 The substituent group in the substituted arylene group may be a phenyl group, an ester group, an amide group, a pyridine group, a cyano group, an alkoxy group, an alkoxysiloxane group, or the like.

[0031] According to the present invention, in some preferred embodiments, in formula (A1), R is independently hydrogen, C1-C 30 Substituted or unsubstituted hydrocarbon groups, C2~C 30 Substituted or unsubstituted alkoxy, C6~C 30 Substituted or unsubstituted aromatic group or C6~C 30 Substituted or unsubstituted alkyl hydroxyl groups. 30 The substituted or unsubstituted hydrocarbon group refers to C1 to C 30 Substituted or unsubstituted alkyl or C2~C 30 Substituted or unsubstituted alkenyl, such as methyl, ethyl, propyl, butyl, vinyl, propenyl, butenyl, etc.; C2~C 30 The substituted or unsubstituted alkoxy group refers to a monovalent functional group formed by removing a hydrogen atom from the carbon of a substituted or unsubstituted alkoxy group containing 2 to 30 carbon atoms, such as methyloxy, ethyloxy, propyloxy or butyloxy; C6~C 30 The substituted or unsubstituted aromatic group refers to a monovalent functional group formed by removing a hydrogen atom from the ring of a substituted or unsubstituted aromatic hydrocarbon containing 6 to 30 carbon atoms, such as phenylene, naphthyl, etc.; C6~C 30 The substituted or unsubstituted alkylhydroxyl group refers to a group formed by replacing one hydrogen on the alkyl group with a hydroxyl group; wherein, C1~C 30 Substituted hydrocarbon groups, C2~C 30 Substituted alkoxy, C6~C 30 Substituted aromatic or C6~C 30 The substituted alkylhydroxyl group may be a phenyl group, an ester group, an amide group, a pyridine group, a cyano group, an alkoxy group, an alkoxysiloxane group, or the like.

[0032] According to the present invention, in some preferred embodiments, the main chain of the polyester graft copolymer contains a structural unit A2 represented by formula (A2);

[0033]

[0034] In formula (A2), X, R, and i have the same definitions as those in formula (A1).

[0035] In the present invention, in formula (A2), the value of i represents the specific structures of the structural unit A2, that is, when i is greater than 1, the structural unit A1 In the example, it indicates that there are at least two different structural units A21, ... A2i on the structural unit A2. For example, when i is 2, it indicates that there are two different structural units They are represented by A21 and A22 respectively, wherein X and / or R in A21 and A22 are different, and so on.

[0036] According to the present invention, in some preferred embodiments, the sum of the degrees of polymerization of structural unit A1 and structural unit A2 is not less than 15, for example, 15, 20, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 500, 600, 1000, 1500, 2000, 3000, 4000, or a range consisting of any two of the above values, preferably 15 to 4000, and more preferably 40 to 385. The composition according to the aforementioned embodiment has higher viscosity and melt strength.

[0037] According to the present invention, in some preferred embodiments, based on the sum of the degrees of polymerization of structural unit A1 and structural unit A2, the proportion of the degree of polymerization of structural unit A2 is 0.1% to 80%, for example, 0.1%, 0.5%, 1%, 2%, 3%, 5%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 50%, 55%, 60%, 70%, 80%, or a range consisting of any two of the above values, preferably 10% to 40%. The composition under the above embodiment has better comprehensive properties.

[0038] According to the present invention, in some preferred embodiments, in the polyester graft copolymer, the average degree of polymerization of the grafted chain segment is not less than 200, for example, 200, 287, 336, 410, 500, 800, 1000, 1200, 1500, 1700, 2000, 3000, or a range consisting of any two of the above values, more preferably 300 to 3000, and even more preferably 400 to 2000. The composition according to the above embodiment has better overall performance.

[0039] According to the present invention, in some preferred embodiments, the main chain of the polyester graft copolymer contains a structural unit A3 represented by formula (A3),

[0040]

[0041] In formula (A3), T1, T2, T3 and T4 are each independently hydrogen or C1-C 30 Organic group.

[0042] According to the present invention, in some preferred embodiments, in formula (A3), T1, T2, T3 and T4 are each independently hydrogen, C1 to C 30 Substituted or unsubstituted hydrocarbon groups, C2~C 30 Substituted or unsubstituted alkoxy, C6~C 30 Substituted or unsubstituted aromatic group or C6~C 30 a substituted or unsubstituted alkylhydroxy group.

[0043] According to the present invention, in some preferred embodiments, based on the sum of the degrees of polymerization of all structural units in the main chain of the polyester graft copolymer, the degree of polymerization of structural unit A3 accounts for no more than 50%, for example, 0%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 35%, 40%, 45%, 50%, or a range consisting of any two of the above values. The composition according to the above embodiment has better comprehensive properties.

[0044] The structural units on the main chain of the polyester graft copolymer in the present invention can be arranged regularly, for example, in the form of block copolymers; or they can be arranged irregularly, that is, in the form of random copolymers. In the present invention, they are preferably in the form of random copolymers. In an exemplary embodiment, the structural formula of the polyester graft copolymer is shown in formula (A),

[0045]

[0046] In formula (A): x1, ..., x i ,y1,y2,……,y i and z each independently represent the degree of polymerization; PM1, ..., PM i represents a polyester segment and the corresponding polymerization degrees of the polyester segments are p1, ..., p i ; x1, ..., x i and z are each independently zero or greater than zero, and x 1、 ..., x i are not all 0 at the same time; y1, ..., y i、 p1, ..., p i Each independently represents a number greater than zero; the subscript i in the degree of polymerization is an arbitrary integer not less than 1 and not greater than 10; z accounts for x1+……+x i +y1+……+y i The ratio of the sum of +z is 0% to 50%.

[0047] According to the present invention, it can be understood that, in formula (A), when i>1, PM1, ..., PM i Different or the same between them, X1, ..., X i Different or the same.

[0048] According to the present invention, it can be understood that in formula (A), p1, ..., p i The average value of refers to the average value of the degree of polymerization of the grafted chain segments in the polyester graft copolymer, which is not less than 150, preferably not less than 200; in some embodiments, p1, ..., p i The average value of is not less than 150, preferably not less than 200;

[0049] x1+……+x i x1+…+x i +y1+……+y i The ratio of the sum refers to the proportion of the degree of polymerization of structural unit A2 to the sum of the degrees of polymerization of structural unit A1 and structural unit A2, which is 0.1% to 80%, preferably 10% to 40%. The composition under the above embodiment has better comprehensive performance; z accounts for x1+...+x i +y1+……+y i The ratio of the sum of +z refers to the proportion of the polymerization degree of the structural unit A3 based on the sum of the polymerization degrees of all structural units in the main chain of the polyester graft copolymer, which is 0% to 50%.

[0050] In the present invention, z accounts for x1+...+x i +y1+……+y i+z is usually a known parameter of the raw material product, and can also be calculated by the integral area of the corresponding characteristic peak of the nuclear magnetic hydrogen spectrum; and x1+……+x i x1+…+x i +y1+……+y i The ratio of the sum can also be calculated by calculating the integrated area of the corresponding characteristic peaks in the H NMR spectrum.

[0051] In the present invention, x1+...+x i +y1+……+y i The sum of x1+x2+...+x is the (total) degree of polymerization of the raw macromolecular initiator. As known to those skilled in the art, the total degree of polymerization of the raw macromolecular initiator can be obtained by the number average molecular weight of the macromolecular initiator such as poly(hydroxyethyl methacrylate), poly(hydroxypropyl methacrylate), poly(hydroxybutyl methacrylate) or its copolymerized derivatives and the sum of z accounting for x1+x2+...+x i +y1+y2+……+y i The degree of polymerization can be obtained by analyzing information such as the ratio of the sum of +z.

[0052] According to the present invention, it is understood that the polyester homopolymer in the composition mainly contains polyester segments, the polyester segments in the polyester homopolymer and the graft segments of the polyester graft copolymer (such as PM1, ..., PM2 in formula (A) i The polyester segments (represented by ) are all derived from compounds capable of providing corresponding polyester chains. In some preferred embodiments, the graft segments of the polyester graft copolymer and the polyester segments of the polyester homopolymer in the composition are simultaneously derived from hydroxy acid monomers or derivatives of hydroxy acid monomers. Using these embodiments, the polyester graft copolymer and the polyester homopolymer achieve a better synergistic effect, being simultaneously formed in situ. The composition exhibits high molecular weight and melt strength, while also having good processability.

[0053] According to the present invention, in some more preferred embodiments, the graft segments of the polyester graft copolymer and the polyester segments of the polyester homopolymer in the composition are derived from lactide monomers and / or lactone monomers. Using these embodiments, the polyester graft copolymer and the polyester homopolymer exhibit enhanced synergy, resulting in a composition having high molecular weight and melt strength while also exhibiting good processability.

[0054] According to the present invention, in some more preferred embodiments, the lactide monomer is an α-hydroxy acid-based or β-hydroxy acid-based lactide monomer.

[0055] According to the present invention, the lactide monomer based on α-hydroxy acid or β-hydroxy acid refers to a lactide monomer prepared with α-hydroxy acid or β-hydroxy acid as raw material and alcohol. In some preferred embodiments, the lactide monomer is selected from one or more of methyl glycolate, glycolic acid, glycolide, lactide, butyride, valeride and hexamethylenete.

[0056] According to the present invention, in some more preferred embodiments, the lactone monomer is selected from β-butyrolactone, δ-valerolactone, ε-caprolactone, β-propiolactone, β-valerolactone, γ-butyrolactone, γ-valerolactone, γ-octalactone, β-methyl-δ-valerolactone, δ-stearolactone, 2-methyl-ε-caprolactone, 4-methyl-ε-caprolactone, and one or more of ε-palmitolactone in ε-octalactone, preferably one or more of β-butyrolactone, δ-valerolactone and ε-caprolactone.

[0057] According to the present invention, in some more preferred embodiments, the graft segments of the polyester graft copolymer and the polyester chains in the polyester homopolymer in the composition are derived from one or more of methyl glycolate, glycolic acid and glycolide, that is, the structural formula of the polyester graft copolymer is as shown in formula (I),

[0058]

[0059] In formula (I): x1, ..., x i ,y1,y2,……,y i ,z,p1,……,p i ,i,R1,……,R i , T1, T2, T3 and T4 are defined as in formula (A).

[0060] According to the present invention, the degree of polymerization of the polyester segment (eg, polyglycolic acid segment) of the polyester graft copolymer is p(p1, ..., p i In some embodiments, p may be greater than or equal to 40, preferably p is greater than or equal to 50, more preferably p is greater than or equal to 50, and p is less than or equal to 3000, further preferably p is 70 to 2000, and further preferably 70 to 1000.

[0061] In the present invention, the value of p can be calculated by the following formula (a):

[0062] p = (M2-M0) / (y1+……+y i *M m ) (a)

[0063] In the above formula (a), M2 and M0 are the number average molecular weight of the polyester graft copolymer and the number average molecular weight of the macromolecular initiator, respectively, in g / mol; y1, ..., yi M is the degree of polymerization in formula (A) or formula (I), which can be determined by a detection method such as nuclear magnetic detection method; m is the molecular weight of the polyester repeating unit, for example, when the monomer is glycolide, M m It is 58g / mol.

[0064] In the present invention, optionally, the lower limit of the p-value can be calculated by the following formula (b):

[0065] p > (M2-M0) / [(x1+……+x i +y1+……+y i )*M m ] (b)

[0066] In the above formula (b), M2, M0 and M m is as described above with respect to formula (a); x1+……+x i +y1+……+y i is the degree of polymerization of the hydroxyl chain segment in the macromolecular initiator, and its value can be calculated by z accounting for x1+…+x i +y1+……+y i The ratio of the sum of +z and the total degree of polymerization were calculated.

[0067] Alternatively, the value of p can be obtained in the following manner: obtain a polyester composition, fully hydrolyze it (i.e., the polyester chains are completely hydrolyzed into small molecules), collect the macroinitiator and characterize its structure, and then obtain the value of p in the manner disclosed in the present invention. For example, the polyester composition can be placed in water at 60 to 80° C. until it is fully hydrolyzed (i.e., the polyester chains are completely hydrolyzed into small molecules), and then the water is removed by means of reduced pressure distillation, vacuum freeze drying, or physical adsorption; the residue is dissolved with a solvent such as dimethyl sulfoxide, and then the macroinitiator is separated (e.g., by chromatography, etc.) and its structure is characterized; the number average molecular weight and hydroxyl content (x1+…+x i +y1+……+y i ), and obtain the value of p according to the method disclosed in the present invention.

[0068] According to the embodiments listed in the present invention, the p values of the polyester compositions obtained by calculation using formula (b) are all greater than 150.

[0069] According to the present invention, in some preferred embodiments, the polyester homopolymer contains polyester segments in a polyester graft copolymer. The composition under the aforementioned embodiment has higher viscosity and melt strength, as well as excellent toughness and sufficient processability (melt fluidity).

[0070] In the present invention, those skilled in the art know that when preparing a general homopolymer, a small molecule initiator can be selectively used. In a preferred embodiment, the polyester homopolymer contains a small molecule initiator segment (M) provided by a small molecule initiator. j , j is any integer between 1 and 20, for example, 1, 2, 3, 4, 5, 6, 8, 10, 12, 13, 15, 18, or 20, preferably any integer between 1 and 6; and M is each an imino group, a nitro group, or an ether bond. The composition according to the above embodiment has higher viscosity and melt strength, as well as excellent toughness and sufficient processability (melt flowability).

[0071] According to the present invention, in some preferred embodiments, the polyester homopolymer contains an end-capping group R, where R is hydrogen, an aliphatic group or an aromatic group, preferably hydrogen, an alkyl group or an aromatic hydrocarbon group with a molecular weight of 14 to 1000 g / mol.

[0072] According to the present invention, in some preferred embodiments, the total degree of polymerization of the polyester segments in the polyester homopolymer is 100 to 5000, preferably 1000 to 4000. The composition under the aforementioned embodiment has higher viscosity and melt strength, as well as excellent toughness and sufficient processability (melt fluidity).

[0073] According to the present invention, in some preferred embodiments, the structural formula of the polyester homopolymer is as shown in formula (II),

[0074]

[0075] In formula (II): j is directly connected to R The number of, j ≥ 1, preferably j is any integer between 1 and 20, preferably any integer between 1 and 6; M1, ..., M j Each is an imino group, a secondary amino group or an ether bond; R is at least one of hydrogen, an aliphatic group or an aromatic group, preferably hydrogen, an alkyl group or an aromatic hydrocarbon group with a molecular weight of 14 to 1000 g / mol; PM1, ..., PM j represents a polyester segment and the corresponding polymerization degrees of the polyester segments are p1, ..., p j .

[0076] According to the present invention, in some further preferred embodiments, the structural formula of the polyester homopolymer is as shown in formula (III),

[0077]

[0078] In formula (III): n1, ..., n j Each is the degree of polymerization; j is directly connected to R The number of, j ≥ 1, preferably j is any integer between 1 and 20, preferably any integer between 1 and 6; M1, ..., M j Each is an imino group, a secondary amino group or an ether bond; R is at least one of hydrogen, an aliphatic group or an aromatic group, preferably hydrogen, an alkyl group or an aromatic hydrocarbon group with a molecular weight of 14 to 1000 g / mol; n1, ..., n j The sum is 100 to 5000, preferably 1000 to 4000.

[0079] According to the present invention, it can be understood that when j>1, M1, ..., M j Different or the same.

[0080] In the present invention, in formula (III), n1, ..., n j The sum can be obtained by dividing the number average molecular weight of the polyester homopolymer, such as polyglycolic acid homopolymer, by the repeating unit molecular weight as measured by GPC.

[0081] According to the present invention, the degree of polymerization (x1, ..., x i ,y1,……,y i ,z,p1,……,p i , n1, ..., n j ) are statistical averages and are rounded off during calculation.

[0082] According to the present invention, in the polyester composition comprising a polyester graft copolymer and a polyester homopolymer, the polyester graft copolymer contains 0.001 to 10 parts by mass (e.g., 0.001 parts, 0.002 parts, 0.003 parts, 0.004 parts, 0.005 parts, 0.006 parts, 0.007 parts, 0.008 parts, 0.009 parts, 0.010 parts, 0.011 parts, 0.012 parts, 0.013 parts, 0.014 parts, 0.015 parts, 0.016 parts, 0.017 parts, 0.018 parts, 0.019 parts, 0.019 parts, 0.020 parts, 0.021 parts, 0.022 parts, 0.023 parts, 0.024 parts, 0.025 parts, 0.026 parts, 0.027 parts, 0.028 parts, 0.029 parts, 0.030 parts, 0.031 parts, 0.032 parts, 0.034 parts, 0.035 parts, 0.036 parts, 0.037 parts, 0.038 parts, 0.039 parts, 0.040 parts, 0.041 parts, 0.042 parts, 0.043 parts, 0.044 parts, 0.045 parts, 0.046 parts, 0.047 parts, 0.048 parts, 0.050 parts, 0.051 parts, 0.052 parts, 0.005 parts, 0.006 parts, 0.007 parts, 0.008 parts, 0.009 parts, 0.010 parts, 0.011 parts, 0.012 parts, 0.013 parts, 0.014 parts, 0.015 parts, 0.016 parts, 0.017 parts, 0.018 parts, 0.019 parts, 0.020 parts, 0.021 parts, 0.022 parts, 0.023 parts, 0.024 parts, 0.025 parts, 0.026 parts 6 parts, 0.027 parts, 0.028 parts, 0.029 parts, 0.030 parts, 0.035 parts, 0.040 parts, 0.050 parts, 0.060 parts, 0.070 parts, 0.080 parts, 0.090 parts, 0.10 parts, 0.11 parts, 0.12 parts, 0.13 parts, 0.14 parts, 0.15 parts, 0.16 parts, 0.17 parts, 0.18 parts, 0.19 parts, 0.20 parts, 0.30 parts , 0.40 parts, 0.50 parts, 0.60 parts, 0.70 parts, 0.80 parts, 0.90 parts, 1.0 parts, 1.5 parts, 2.0 parts, 2.5 parts, 3.0 parts, 3.5 parts, 4.0 parts, 4.5 parts, 5.0 parts, 6.0 parts, 7.0 parts, 8.0 parts, 9.0 parts, 10.0 parts, or a range consisting of any two of the above values), preferably 0.005 to 3 parts by mass, more preferably 0.01 to 1 part by mass and containing 0.001 to 1 parts by mass (e.g., 0.001, 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, 0.010, 0.011, 0.012, 0.013, 0.014, 0.015, 0.016, 0.017, 0.018, 0.019, 0.020, 0.021, 0.022, 0.023, 0.024, 0.025, 0.026, 0.027, 0.028, 0.029, 0.030, 0.031, 0.032, 0.033, 0.034, 0.035, 0.036, 0.037, 0.038, 0.039, 0.040, 0.041, 0.042, 0.043, 0.044, 0.045, 0.046, 0.047, 0.048, 0.049, 0.050, 0.051, 0.052, 0.053, 0.054, 0.055, 0.056, 0.057, 0.058, 0.059, 0.060, 0.061, 0.062, 0.063, 0.064, 0.065 0.022 parts, 0.023 parts, 0.024 parts, 0.025 parts, 0.026 parts, 0.027 parts, 0.028 parts, 0.029 parts, 0.030 parts, 0.031 parts, 0.032 parts, 0.033 parts, 0.034 parts, 0.035 parts, 0.036 parts, 0.037 parts, 0.038 parts, 0.039 parts, 0.040 parts, 0.041 parts, 0.042 parts, 0.043 parts, 0.044 parts, 0.045 parts, 0.046 parts, 0.047 parts, 0.048 parts, 0.049 parts, 0.050 parts, 0.051 parts, 0.052 parts, 0.053 parts, 0.054 parts, 0.055 parts, 0.056 parts, 0.057 parts, 0.058 parts, 0.059 parts, 0.060 parts, 0.061 parts, 0.062 parts, 0.063 parts, 0.064 parts, 0.065 parts, 0.066 parts, 0.067 parts, 0.068 parts, 0.069 parts 0.1 to 0.1 parts by mass, 0.070 to 0.080 parts, 0.090 parts, 0.10 parts, 0.11 parts, 0.12 parts, 0.13 parts, 0.14 parts, 0.15 parts, 0.16 parts, 0.17 parts, 0.18 parts, 0.19 parts, 0.20 parts, 0.30 parts, 0.40 parts, 0.50 parts, 0.60 parts, 0.70 parts, 0.80 parts, 0.90 parts, 1.0 parts, or a range consisting of any two of the above values), preferably 0.01 to 0.1 parts by mass x1, ..., x i ,y1,……,y i and z each independently represent the degree of polymerization; PM1, ..., PM i represents a polyester segment and the corresponding polymerization degrees of the polyester segments are p1, ..., p i ; x1, ..., x i and z are each independently zero or greater than zero, and x 1、 ..., x i are not all 0 at the same time; y1, ..., y i、 p1, ..., p i Each of them is independently a number greater than zero; the subscript i is an integer not less than 1 and not greater than 10; z occupies x1+……+x i +y1+……+y iThe ratio of the sum of z and z is 0% to 50%. The composition according to the aforementioned embodiment has higher viscosity and melt strength, as well as excellent toughness and sufficient processability (melt fluidity).

[0083] In the present invention, it is understood that when the polyester segments in the polyester graft copolymer and the polyester homopolymer are both polyglycolic acid chains, the polyester segments in the polyester graft copolymer and the polyester homopolymer are polyglycolic acid segments. (i.e. The total mass of is 100 parts by mass; Including those present in formula (I) and in formula (III) middle).

[0084] In the present invention, the mass content of the segments / structures / polymer chains in the combination can be detected by methods known in the art, such as nuclear magnetic resonance and / or infrared methods; alternatively, the mass content of each of the above segments / structures / polymer chains can be calculated based on the amount of material added during the preparation process.

[0085] According to the present invention, in some preferred embodiments, the content of the polyester graft copolymer is 0.1% by mass to 80.0% by mass. For example, the content of the polyester graft copolymer can be 0.1% by mass, 0.5% by mass, 1.0% by mass, 2.0% by mass, 3.0% by mass, 4.0% by mass, 5.0% by mass, 6.0% by mass, 7.0% by mass, 8.0% by mass, 9.0% by mass, 10% by mass, 11% by mass, 12% by mass, 13% by mass, 14% by mass, 15% by mass, 16% by mass, 17% by mass, 18% by mass, 19% by mass, 20% by mass, 21% by mass, 22% by mass, 23% by mass, 24% by mass, 25% by mass, 26% by mass, 27% by mass, 28% by mass, 29% by mass, 30.0% by mass, 35% by mass, 40% by mass, 45% by mass, 50% by mass, 55% by mass, 65% by mass, 75% by mass, 80% by mass, or a range consisting of any two of the above values, preferably 0.5% by mass to 55.0% by mass, and more preferably 1.0% by mass to 30.0% by mass. The composition according to the aforementioned embodiment has higher viscosity and melt strength, as well as excellent toughness and sufficient processability (melt fluidity).

[0086] According to the present invention, in some embodiments, relative to the total mass of the polyester graft copolymer and the polyester homopolymer, the content of the polyester homopolymer is 20% to 99.9% by mass, for example, the content of the polyester homopolymer may be 20% by mass, 25.0% by mass, 30.0% by mass, 35.0% by mass, 40.0% by mass, 45.0% by mass, 50.0% by mass, 55.0% by mass, 60.0% by mass, 65.0% by mass, 70.0% by mass, 71.0% by mass, 72.0% by mass, 73.0% by mass, 74.0% by mass, 75.0% by mass, 76.0% by mass, 77.0% by mass, 78.0% by mass, 79.0 mass%, 80.0 mass%, 81.0 mass%, 82.0 mass%, 83.0 mass%, 84.0 mass%, 85.0 mass%, 86.0 mass%, 87.0 mass%, 88.0 mass%, 89.0 mass%, 90.0 mass%, 91.0 mass%, 92.0 mass%, 93.0 mass%, 94.0 mass%, 95.0 mass%, 96.0 mass%, 97.0 mass%, 98.0 mass%, 99.0 mass%, 99.9 mass%, or a range consisting of any two of the above values, preferably 45.0 mass% to 99.5 mass%, more preferably 70.0 mass% to 99.0 mass%.

[0087] According to the present invention, in some preferred embodiments, the total weight average molecular weight of the composition is 120,000 to 1.5 million g / mol. For example, the total weight average molecular weight of the polyester composition can be 120,000 g / mol, 130,000 g / mol, 130,000 g / mol, 140,000 g / mol, 150,000 g / mol, 160,000 g / mol, 170,000 g / mol, 180,000 g / mol, 190,000 g / mol, 200,000 g / mol, 210,000 g / mol, 220,000 g / mol, 230,000 g / mol, 240,000 g / mol, 250,000 g / mol. / mol, 300,000 g / mol, 350,000 g / mol, 400,000 g / mol, 450,000 g / mol, 500,000 g / mol, 600,000 g / mol, 700,000 g / mol, 800,000 g / mol, 900,000 g / mol, 1,000,000 g / mol, 1,100,000 g / mol, 1,200,000 g / mol, 1,300,000 g / mol, 1,400,000 g / mol, 1,500,000 g / mol, and a range consisting of any two of the above values, preferably 160,000 to 1,000,000 g / mol, more preferably 200,000 to 500,000 g / mol. The composition under the aforementioned embodiment has higher high viscosity and melt strength, as well as excellent toughness and sufficient processing performance (melt fluidity).

[0088] In the present invention, the "overall weight average molecular weight" refers to the weight average molecular weight of the polyester composition as a whole.

[0089] According to the present invention, in some preferred embodiments, the overall molecular weight polydispersity index of the polymer composition is 1.5 to 20.0. For example, the overall molecular weight polydispersity index of the polyester composition can be 1.5, 1.74, 2.19, 2.27, 3.5, 4.5, 6.0, 8.0, 8.5, 9.0, 12.0, or a range consisting of any two of the above values, preferably 2.0 to 12.0, more preferably 2.0 to 6.0, and even more preferably 2.0 to 3.5. The composition under the aforementioned embodiment has higher viscosity and melt strength, as well as excellent toughness and sufficient processability (melt flowability).

[0090] According to the present invention, in some preferred embodiments, the molecular weight polydispersity index of the polyester graft copolymer is 1.0 to 3.0, for example, 1.0, 1.06, 1.10, 1.12, 1.23, 1.32, 1.40, 1.45, 1.50, or any range consisting of any two of the above values, preferably 1.1 to 1.5. The composition of the aforementioned embodiment has higher viscosity and melt strength, as well as excellent toughness and sufficient processability (melt flowability).

[0091] According to the present invention, in some preferred embodiments, the molecular weight polydispersity index of the polyester homopolymer is 1.0 to 3.0, for example, 1.0, 1.4, 1.59, 2.03, 2.12, 2.5, 3.0, or any range consisting of any two of the above values, preferably 1.4 to 2.5. The composition according to the above embodiment has higher viscosity and melt strength, as well as excellent toughness and sufficient processability (melt flowability).

[0092] According to the present invention, in some preferred embodiments, the molecular weight of the composition is multimodal, and preferably the number of peaks in the molecular weight distribution of the composition is 2-4. The composition under the aforementioned embodiment has higher viscosity and melt strength, as well as excellent toughness and sufficient processing performance (melt fluidity).

[0093] In the present invention, the molecular weight of the composition presents a multimodal distribution, which means that the number of molecular weight distribution peaks of the composition is at least 2.

[0094] According to the present invention, in some embodiments, the peak molecular weight M in the molecular weight distribution curve of the composition is p Greater than 500,000 g / mol (i.e., the peak value in the GPC curve) w ) is greater than 5.7), preferably the number of peaks of 500,000 to 10,000,000 g / mol is at least 1, for example 1, 2 or 3, and the peak molecular weight M pLess than 500,000 g / mol (i.e., the peak value in the GPC curve) w ) is less than 5.7), preferably, the number of peaks of 50,000 to 350,000 g / mol is at least 1, for example 1.

[0095] According to the present invention, the molecular weight distribution curve and the number of peaks in the molecular weight distribution curve can be detected by gel permeation chromatography (GPC). The molecular weight distribution peak is the peak in the GPC curve at the weight average molecular weight (M w ) is greater than 10,000 g / mol (i.e. lg(M w ) is greater than 4.0) where the first derivative is zero and the second derivative is less than zero.

[0096] According to the present invention, in some preferred embodiments, the molecular weight of the polyester graft copolymer is higher than that of the polyester homopolymer. The composition under the aforementioned embodiment has higher viscosity and melt strength, as well as excellent toughness and sufficient processability (melt fluidity).

[0097] According to the present invention, in some more preferred embodiments, the weight-average molecular weight of the polyester graft copolymer is 500,000 to 10 million g / mol, for example, 500,000 g / mol, 1 million g / mol, 1.5 million g / mol, 2 million g / mol, 3 million g / mol, 4 million g / mol, 5 million g / mol, 6 million g / mol, 7 million g / mol, 10 million g / mol, and can be a range consisting of any two of the above values, preferably 1 million to 7 million g / mol, more preferably 1 million to 6 million g / mol. The composition under the aforementioned embodiment has higher high viscosity and melt strength, as well as excellent toughness and sufficient processing properties (melt fluidity).

[0098] According to the present invention, in some more preferred embodiments, the weight average molecular weight of the polyester homopolymer is 50,000 to 350,000 g / mol, for example, 50,000 g / mol, 60,000 g / mol, 70,000 g / mol, 80,000 g / mol, 90,000 g / mol, 100,000 g / mol, 120,000 g / mol, 140,000 g / mol, 160,000 g / mol, 180,000 g / mol, 200,000 g / mol, 220,000 g / mol, 240,000 g / mol, 260,000 g / mol, 280,000 g / mol, 300,000 g / mol, 320,000 g / mol, 330,000 g / mol, 340,000 g / mol, 350,000 g / mol, and can be a range consisting of any two of the above values, preferably 100,000 to 200,000 g / mol. The composition under the aforementioned embodiment has higher high viscosity and melt strength, as well as excellent toughness and sufficient processing properties (melt fluidity).

[0099] The total weight average molecular weight / total number average molecular weight of the polyester composition of the present invention, such as the polyglycolic acid composition, the total molecular weight polydispersity index of the polyglycolic acid composition, the number of molecular weight distribution peaks of the polyglycolic acid composition, the weight average molecular weight / number average molecular weight of the polyglycolic acid graft copolymer, the molecular weight polydispersity index of the polyglycolic acid graft copolymer, the weight average molecular weight / number average molecular weight of the polyester homopolymer, such as the polyglycolic acid homopolymer, the molecular weight polydispersity index of the polyester homopolymer, such as the polyglycolic acid homopolymer, the mass fraction of the polyglycolic acid graft copolymer, the mass fraction of the polyester homopolymer, such as the polyglycolic acid homopolymer, etc. can be detected by gel permeation chromatography (GPC). Specific detection methods are generally known in the art, and conventional detection parameters can be used. For example, the following method can be used: the testing instrument is a PL-GPC50 gel permeation chromatograph from Angilent, USA, and the processing software is GPC offline. The mobile phase is hexafluoroisopropanol containing 5 mmol / L sodium trifluoroacetate, the flow rate is 1 mL / min, the column temperature is 40°C, the injection volume is 100 μL, the standard sample is PMMA, and the sample concentration is 1 mg / mL. The specific values of the above parameters are obtained according to analytical methods known in the art.

[0100] According to the present invention, the polyester composition of the present invention has excellent melt strength. In some embodiments, the melt strength of the composition at 235°C is not less than 4 cN and not more than 200 cN, preferably not less than 8 cN and not more than 100 cN.

[0101] The second aspect of the present invention provides a method for preparing the polyester composition of the first aspect of the present invention, comprising melt-polymerizing a polymer raw material containing a macromolecular initiator and a polyester monomer capable of providing a structural polyester chain segment;

[0102] Wherein, the macromolecular initiator contains structural units The definitions of X, R, and i are the same as those in the polyester copolymer described in the first aspect of the present invention.

[0103] In the present invention, a polyester graft copolymer and a polyester homopolymer are simultaneously formed in situ using the preparation method of the present invention. There is no need to prepare polyester raw materials with different molecular weight distributions by melt blending, which reduces the inevitable degradation of polyester during the blending process of different polyester raw materials. The various components of the prepared polyester composition have a synergistic effect, and comprehensive properties that are difficult for single-component polyesters to have are obtained.

[0104] According to the present invention, in order to achieve a variety of structural and functional regulation, in some preferred embodiments, the macroinitiator contains a structural unit A3 represented by formula (A3),

[0105]

[0106] In formula (A3), T1, T2, T3 and T4 are each independently hydrogen or C1-C 30 Organic group.

[0107] According to the present invention, in order to better achieve melt polymerization, in some preferred embodiments,

[0108] The polymeric raw material also contains a small molecule initiator, j is an integer greater than or equal to 1, M1, ..., M j Each is an imino group, a nitro group or an ether bond, and R is at least one of hydrogen, an aliphatic group or an aromatic group.

[0109] According to the present invention, the polyester monomer capable of providing the polyester structure is selected from hydroxy acid monomers or derivatives of hydroxy acid monomers, preferably selected from lactide monomers and / or lactone monomers.

[0110] According to the present invention, the lactide monomer is an α-hydroxy acid-based or β-hydroxy acid-based lactide monomer. In some preferred embodiments, the lactide monomer is selected from one or more of methyl glycolate, glycolic acid, glycolide, lactide, butyrolactone, valerolactone and hexyl lactide; and / or, the lactone monomer is selected from one or more of β-butyrolactone, δ-valerolactone, ε-caprolactone, β-propiolactone, β-valerolactone, γ-butyrolactone, γ-valerolactone, γ-octalactone, β-methyl-δ-valerolactone, δ-stearolactone, 2-methyl-ε-caprolactone, 4-methyl-ε-caprolactone, and ε-palmitolactone in ε-octalactone.

[0111] According to the present invention, in some preferred embodiments, the lactone monomer is selected from one or more of β-butyrolactone, δ-valerolactone and ε-caprolactone.

[0112] According to the present invention, in some preferred embodiments, the polyester monomer capable of providing a polyester structure is selected from one or more of methyl glycolate, glycolic acid and glycolide.

[0113] According to the present invention, the weight average molecular weight of the macroinitiator is 2000 to 500000 g / mol, preferably 5000 to 50000 g / mol.

[0114] According to the present invention, when z is 0, the macroinitiator is provided The polymer of the structural unit can be exemplified by macromolecular initiators such as polyhydroxyethyl methacrylate, polyhydroxypropyl methacrylate, polyhydroxybutyl methacrylate, etc. When i is greater than 1, and X or R is different, the macromolecular initiator is provided and / or when z is not 0 (the macroinitiator can also provide The comonomer in the copolymer derivative can be any combination of hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, hydroxybutyl acrylate, and hydroxypropyl acrylate, or other monomers, such as ethylene, propylene, n-butene, isobutylene, styrene, 2-methylstyrene, 4-methylstyrene, styrene, allylbenzene, 2-phenyl-1-propene, p-hydroxystyrene, vinyl benzoic acid, p-styrenesulfonic acid, sodium p-styrenesulfonate, vinyl acetate, vinyl butyrate, methyl acrylate, ethyl acrylate, propyl acrylate, isooctyl acrylate, lauryl acrylate, isobornyl acrylate, methyl methacrylate, ethyl methacrylate, Ester, n-butyl methacrylate, t-butyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, isodecyl methacrylate, lauryl methacrylate, glycidyl methacrylate, dimethylaminoethyl methacrylate, dodecafluoroheptyl methacrylate, propenyl phenyl ether, ethyl undecylenate, methyl palmitoleate, oleamide, erucamide, glyceryl erucate, vinyl laurate, maleic anhydride, diethyl maleate, dimethylmaleic anhydride, itaconic anhydride, vinylpyrrolidone, vinylpyridine, acrylonitrile, acrylamide, N-ethylacrylamide, N-isopropylacrylamide, vinyltriethoxysiloxane or acrylateoxypropylbis(trimethylsiloxy)methylsilane.

[0115] According to the present invention, in some embodiments, the small molecule initiator is selected from water and / or a small molecule compound containing hydroxyl groups and / or amino groups with a boiling point greater than 160°C.

[0116] According to the present invention, in some preferred embodiments, the molecular weight of the small molecule compound containing hydroxyl and / or amino groups is not greater than 1000 g / mol; preferably 60 to 300 g / mol. The small molecule initiators with different particle sizes include water, 1,4-butanediol, etc.

[0117] According to the present invention, in some embodiments, the content of hydroxyl groups contained in the macroinitiator relative to each gram of polyester monomer is 0.1 μmol / g monomer to 1.5 mmol / g monomer, for example, it can be 0.1 μmol / g monomer, 1.2 μmol / g monomer, 1.5 μmol / g monomer, 2.0 μmol / g monomer, 2.3 μmol / g monomer, 10.0 μmol / g monomer, 76.9 μmol / g monomer, 0.5 mmol / g monomer, 1.0 mmol / g monomer, or a range consisting of any two of the above values, preferably 0.5 μmol / g monomer to 1.0 mmol / g monomer, more preferably 1.0 μmol / g monomer to 0.5 mmol / g monomer.

[0118] According to the present invention, in some embodiments, the active hydrogen content of the small molecule initiator is 3.0 μmol / g monomer to 40.0 μmol / g monomer per gram of polyester monomer, calculated as active hydrogen, for example, 11.0 μmol / g monomer, 15.6 μmol / g monomer, 21.1 μmol / g monomer, 28.3 μmol / g monomer, 30.0 μmol / g, 31.67 μmol / g monomer, 40.0 μmol / g monomer, or a range consisting of any two of the above values, preferably 10.0 μmol / g monomer to 30.0 μmol / g monomer.

[0119] In the present invention, "active hydrogen" refers to hydrogen contained in water, hydroxyl groups (-OH), primary amino groups (-NH2) and secondary amino groups (-NH-). According to the present invention, each water molecule contains one "active hydrogen".

[0120] In the present invention, the content of "active hydrogen" in the small molecule initiator can be calculated by the following formula (c): H :

[0121] n H =m H2O / 18+m s1 *n s1 / M s1 + m s2 *n s2 / M s2 +……+ m si *n si / M si (c)

[0122] In the above formula (c), n H The unit is μmol / g monomer. When the monomer is glycolide, it is μmol / g glycolide; m H2O is the mass content of water in unit monomer, unit: ppm; m s1 、m s2 、……、m si Respectively represent the mass content of small molecule initiator s1, small molecule initiator s2, ..., small molecule initiator si in the unit monomer, unit: ppm; n s1 、n s2 、……、n si Respectively represent the number of “active hydrogens” contained in each small molecule initiator s1, small molecule initiator s2, ..., small molecule initiator si; M s1 、M s2 ,……,M si They represent the molecular weights of small molecule initiator s1, small molecule initiator s2, ..., small molecule initiator si respectively, unit: g / mol.

[0123] According to the present invention, in some embodiments, the amount of the macroinitiator is 0.001 to 10 parts by mass relative to 100 parts by mass of the polyester monomer, for example, 0.001 parts by mass, 0.015 parts by mass, 0.03 parts by mass, 1 part by mass, 3 parts by mass, 5 parts by mass, 7 parts by mass, 10 parts by mass, or a range consisting of any two of the above values, preferably 0.005 to 3 parts by mass, and more preferably 0.01 to 1 part by mass.

[0124] According to the present invention, in some embodiments, for 100 parts of polyester monomer, the amount of the small molecule initiator is 0.001 to 1 part by mass, for example, 0.001 part by mass, 0.035 part by mass, 0.05 part by mass, 0.1 part by mass, 0.3 part by mass, 0.5 part by mass, 1 part by mass, or a range consisting of any two of the above values, preferably 0.01 to 0.1 part.

[0125] According to the present invention, in some preferred embodiments, the conditions for the melt polymerization include: a temperature of 120 to 300°C, preferably 160 to 250°C, and more preferably 200 to 240°C.

[0126] According to the present invention, in some preferred embodiments, the conditions for the melt polymerization include: a reaction time of 0.5 to 60 minutes, preferably 1 to 10 minutes.

[0127] According to the present invention, any device capable of realizing melt polymerization in the art can be used to carry out the melt polymerization of the present invention. Preferably, the melt polymerization is carried out in a melt mixing device.

[0128] According to the present invention, in some preferred embodiments, the melt polymerization is carried out in a continuous twin-screw extruder. The continuous twin-screw extruder in the present invention can be one or at least two, for example 2, 3 or 4, twin-screw extruders connected in series.

[0129] According to the present invention, in some preferred embodiments, the polymerization reaction conditions of the continuous twin-screw extruder include: a temperature of 180 to 250°C, preferably 210 to 240°C.

[0130] According to the present invention, in some preferred embodiments, the polymerization reaction conditions of the continuous twin-screw extruder include: a screw speed of 5 to 300 rpm, preferably 40 to 150 rpm.

[0131] According to the present invention, in some preferred embodiments, the polymerization reaction conditions of the continuous twin-screw extruder include: an aspect ratio of 25 to 80, preferably 40 to 70.

[0132] According to the present invention, in some preferred embodiments, the melt polymerization is carried out in the presence of a catalyst and optionally an antioxidant.

[0133] According to the present invention, the catalyst used in the melt polymerization can be a conventional melt polymerization catalyst in the art. Preferably, the catalyst is selected from a salt compound of at least one of Group IIA metal elements, Group IIIA metal elements, Group IVA metal elements, Group VA metal elements and transition metal elements, or an organic guanidine catalyst. Preferably, the catalyst is a salt compound of at least one of Sn, Bi, Mg, Al, Ca, Fe, Mn, Ti and Zn, and more preferably, the catalyst is a Sn salt. In the embodiments of the present invention, stannous octoate is used as a catalyst to illustrate the advantages of the present invention, but the present invention is not limited thereto.

[0134] According to the present invention, the amount of catalyst used in melt polymerization can be any amount that can promote melt polymerization. Preferably, the amount of the catalyst used is 0.005 to 1 part by mass relative to 100 parts of monomer, for example, 0.01 part by mass, 0.05 part by mass, 0.1 part by mass, 0.2 part by mass, and preferably 0.01 to 0.2 part by mass.

[0135] According to the present invention, the optional antioxidant refers to the presence or absence of an antioxidant. In order to extend the service life of the composition, it is preferably contained. The antioxidant can be a conventional antioxidant in the art. In the present invention, antioxidant 1010 and antioxidant 626 are used as examples to illustrate the advantages of the present invention, but the present invention is not limited to this.

[0136] The third aspect of the present invention provides a polyester composition prepared by the preparation method of the second aspect of the present invention.

[0137] In the present invention, a polyester graft copolymer and a polyester homopolymer are simultaneously formed through in-situ polymerization. The various components in the polyester composition act synergistically with each other to simultaneously provide high viscosity and melt strength, as well as high toughness and sufficient processing performance (melt fluidity), thereby obtaining comprehensive properties that are difficult for a single-component polyester to have, and can better meet the application requirements of film blowing, foaming, rod extrusion, etc. that require high melt strength.

[0138] The fourth aspect of the present invention provides a product, which is made from raw materials comprising the polyester composition of the present invention.

[0139] According to the present invention, in some preferred embodiments, the product is selected from a film, a rod, a tube, a wire, a sheet or a special-shaped part.

[0140] The present invention will be described in detail below by way of examples. In the following examples:

[0141] Glycolide was purchased from Shenzhen Boli Biomaterial Co., Ltd. with a purity of ≥99.5%, a moisture content of ≤500 ppm, and an acid value of ≤3 mmol / kg.

[0142] Stannous octoate and 1,4-butanediol (BDO) were purchased from Sinopharm Chemical Reagent Co., Ltd.; the purity of stannous octoate was AR grade, and the purity of 1,4-butanediol was CP grade.

[0143] Antioxidant 1010 was purchased from BASF (China) Co., Ltd., and antioxidant 626 was purchased from Shanghai MacLean Biochemical Technology Co., Ltd., with a purity of ≥95%.

[0144] Poly(hydroxyethyl methacrylate) was purchased from Aladdin Biochemical Technology Co., Ltd., with a number average molecular weight of about 10,000 g / mol and a weight average molecular weight of about 20,000 g / mol.

[0145] Hydroxyethyl methacrylate was purchased from Beijing Inokai Technology Co., Ltd. with a purity of 96% and containing 250 ppm of MEHQ stabilizer.

[0146] Ethyl methacrylate was purchased from Beijing Inokai Technology Co., Ltd. with a purity of 99% and containing 10-20 ppm of MEHQ stabilizer.

[0147] Polyglycolide (PGA) was purchased from Cobion-Prak, the Netherlands, and is a GMP-grade glycolide homopolymer with an average intrinsic viscosity of 1.2 dl / g.

[0148] The random copolymer of hydroxyethyl methacrylate and ethyl methacrylate is homemade. The general preparation method is as follows: hydroxyethyl methacrylate, ethyl methacrylate and a free radical initiator (such as azobisisobutyronitrile) are added to a reactor in a molar ratio of 1:1:0.1, heated to 60-70°C, and stirred for 4 hours.

[0149] The present invention measures the performance of the present invention according to the following method:

[0150] Gel Permeation Chromatography (GPC): The instrument used was a PL-GPC50 gel permeation chromatograph from Angilent, USA, and the processing software was GPC offline. The mobile phase was hexafluoroisopropanol containing 5 mmol / L sodium trifluoroacetate, with a flow rate of 1 mL / min, a column temperature of 40°C, an injection volume of 100 μL, and PMMA as the standard sample at a sample concentration of 1 mg / mL.

[0151] Melt strength testing: The test was conducted on a Rosand RH7 high-pressure capillary rheometer from Malvern Panalytical (China), using the Haul Off model (2.0 mm diameter, 20 mm length). The barrel push rod downward speed was 15 mm / min, the test temperature was 235°C, the initial draw-off speed of the winder was 3 m / min, and the final draw-off speed was 50 m / min. The speed increased at a constant rate over a 3-minute ramp-up period, and 30 data points were collected.

[0152] Example 1

[0153] Synthesis of the polyester composition: Glycolide (water content 370 ppm), stannous octoate, polyhydroxyethyl methacrylate (PHEMA), 1,4-butanediol (BDO), antioxidant 1010, and antioxidant 626 were uniformly mixed in a mass ratio of 100:0.05:0.015:0.035:0.5:0.3, and then extruded into pellets using a Labtech parallel co-rotating twin-screw extruder (screw diameter: 20 mm, aspect ratio: 40). The extruder has 11 sections from the feed port to the die, numbered 1 to 11. Section 1 only serves to add materials and cannot be heated; sections 2 to 11 of the extruder are The temperatures are 160°C, 200°C, 220°C, 220°C, 220°C, 220°C, 230°C, 235°C and 240°C respectively; the feeding rate is 3 kg / h, the screw speed is 150 rpm, and the average residence time is about 3 min; the hydroxyl content from PHEMA in the raw material is 1.15 μmol / g glycolide, the active hydrogen content in the small molecule initiator 1,4-butanediol is 7.76 μmol / g glycolide, and the active hydrogen content from water is calculated as 20.6 μmol / g glycolide, so the total active hydrogen content in the raw material is 29.5 μmol / g glycolide.

[0154] The polyester composition contains a polyester graft copolymer and a polyester homopolymer, wherein the polyester graft copolymer contains Structural unit A1 and Structural unit A2; (i is 1, X is ethylene, and R is methyl), the grafted chain segment in the graft copolymer is a medium-sized polyglycolic acid chain segment; calculated by nuclear magnetic hydrogen spectrum integration, based on the sum of the polymerization degrees of structural unit A1 and structural unit A2, the polymerization degree of structural unit A2 accounts for approximately 30%; at the same time, from the number average molecular weight of the raw materials and the molecular weight of the repeating unit, it can be obtained that the total polymerization degree of all structural units on the main chain of the polyester graft copolymer is approximately 77, and the total polymerization degree of structural unit A1 is approximately 54. According to formula (a) in the specification, it can be obtained that the polymerization degree p of the polyglycolic acid segment in the graft copolymer is 410.

[0155] Example 2

[0156] Synthesis of a polyester composition: The synthesis method was the same as in Example 1, except that the equipment was changed to a Eurolab parallel co-rotating twin-screw extruder (screw diameter: 16 mm, aspect ratio 40), and the ratio of glycolide (moisture content 370 ppm), stannous octoate, polyhydroxyethyl methacrylate (PHEMA), 1,4-butanediol (BDO), antioxidant 1010, and antioxidant 626 was set to 100:0.10:0.030:0.050:0.3:0.6. The temperatures were changed to: 160°C, 200°C, 220°C, 220°C, 220°C, 220°C, 220°C, 220°C, 220°C, 220°C, 220°C, 220°C, 220°C, 220°C, the screw speed was changed to 120 rpm, the feed rate was changed to 2 kg / h, and the average residence time was approximately 4 min. The hydroxyl content of the raw material derived from PHEMA is 2.31 μmol / g glycolide, the active hydrogen content of the small molecule initiator 1,4-butanediol is 11.1 μmol / g glycolide, and the active hydrogen content derived from water is calculated as 20.6 μmol / g glycolide. Therefore, the total active hydrogen content in the raw material is 34.0 μmol / g glycolide. The polyester composition contains a polyester graft copolymer and a polyester homopolymer. According to formula (b) in the specification, the degree of polymerization (p) of the polyglycolic acid segments in the graft copolymer is greater than 287.

[0157] Example 3

[0158] Synthesis of polyester composition: The synthesis method was the same as in Example 1, except that the amount of PHEMA was adjusted to 1 phr, 1,4-butanediol (BDO) was not added, and the ratio of glycolide (water content 280 ppm), stannous octoate, polyhydroxyethyl methacrylate (PHEMA), antioxidant 1010 and antioxidant 626 was set to 100:0.05:1.0:0.3:0.3, and the equipment was changed to a Eurolab parallel co-rotating twin-screw extruder (screw diameter: 16 mm, aspect ratio 40 ), the temperature was changed to: 120°C, 180°C, 230°C, 230°C, 230°C, 230°C, 230°C, 230°C, 230°C, 210°C, the screw speed was changed to 100 rpm, the feed rate was changed to 1 kg / h, and the average residence time was approximately 6 minutes. The hydroxyl content of the raw material from PHEMA was 76.8 μmol / g glycolide, and the active hydrogen content from water was calculated as 15.6 μmol / g glycolide, so the total active hydrogen content in the raw material was 92.4 μmol / g glycolide. The polyester composition contained a polyester graft copolymer and a polyester homopolymer. According to formula (b) in the specification, the degree of polymerization (p) of the polyglycolic acid segments in the graft copolymer was greater than 336.

[0159] Example 4

[0160] Synthesis of the polyester composition: The synthesis method was the same as in Example 2, except that polyhydroxyethyl methacrylate (PHEMA) was replaced with a hydroxyethyl methacrylate-ethyl methacrylate random copolymer (P(HEMA-co-EMA) having a number average molecular weight of approximately 20,000 g / mol and a hydroxyethyl methacrylate molar content of approximately 50%. The amount of antioxidant 626 was changed to 0.3 phr. The hydroxyl content of the hydroxyethyl methacrylate-ethyl methacrylate random copolymer in the raw material was 1.23 μmol / g glycolide, the active hydrogen content of the small molecule initiator 1,4-butanediol was 11.1 μmol / g glycolide, and the active hydrogen content from water was calculated as 20.6 μmol / g glycolide. Therefore, the total active hydrogen content in the raw material was 32.9 μmol / g glycolide. The polyester composition contained a polyester graft copolymer and a polyester homopolymer. According to formula (b) in the specification, the degree of polymerization p of the polyglycolic acid segment in the graft copolymer was greater than 375.

[0161] Comparative Example 1

[0162] Synthesis of the polyester composition: The synthesis method was the same as in Example 2, except that the macroinitiator poly(hydroxyethyl methacrylate) (PHEMA) was omitted, and the ratio of glycolide (water content 180 ppm), stannous octoate, 1,4-butanediol, antioxidant 1010, and antioxidant 626 was changed to 100:0.10:0.050:0.3:0.6. The active hydrogen content of the small molecule initiator 1,4-butanediol in the raw material was 11.1 μmol / g glycolide. The active hydrogen content from the water was calculated as 10.0 μmol / g glycolide, resulting in a total active hydrogen content of 21.1 μmol / g glycolide.

[0163] Comparative Example 2

[0164] Commercially available pure polyglycolide (PGA) was purchased from the GMP-grade glycolide homopolymer of Cobion-Prak, the Netherlands, with an average intrinsic viscosity of 1.2 dl / g.

[0165] Comparative Example 3

[0166] Synthesis of the polyester composition: The synthesis method was the same as in Example 3, except that the PHEMA dosage was increased to 20 phr. The hydroxyl content in the raw material, derived from PHEMA, was 1.54 mmol / g glycolide, and the active hydrogen content, derived from water, was 15.6 μmol / g glycolide. Therefore, the total active hydrogen content in the raw material was 1.56 mmol / g glycolide.

[0167] The polyester composition contains a polyester graft copolymer and a polyester homopolymer, wherein the polyester graft copolymer contains Structural unit A1 and Structural unit A2; (i is 1, X is ethylene, and R is methyl). Based on the sum of the degrees of polymerization of structural unit A1 and structural unit A2, the degree of polymerization of structural unit A2 accounts for approximately 60%. At the same time, based on the number average molecular weight of the raw materials and the molecular weight of the repeating units, it can be obtained that the total degree of polymerization of all structural units on the main chain of the polyester graft copolymer is approximately 77. The total degree of polymerization of structural unit A1 is approximately 31. According to formula (a) in the specification, the degree of polymerization of polyglycolic acid in the graft copolymer, p, is approximately 123.

[0168] The raw material ratios of the above examples and comparative examples are shown in Table 1.

[0169] Table 1

[0170]

[0171] Note: The above proportions are based on 100 parts by mass (phr) of glycolide monomer; the total small molecule initiator includes both the added small molecule initiator and the water contained in glycolide.

[0172] Test Example 1

[0173] The molecular weight of the polymers in some embodiments and comparative examples was characterized by GPC. The analysis results are shown in Table 2. The GPC curves of some embodiments and comparative examples are shown in Table 2. Figure 1 shown.

[0174] Table 2

[0175]

[0176] *Calculated from the integrated area ratio of the GPC curve. The ordinate and abscissa of the GPC curve are related to the amount of substance and molecular weight of the polymer, respectively. Therefore, integrating the curve can be used to obtain the corresponding component mass. In other words, the ratio of the integrated area to the total integrated area is the corresponding mass fraction.

[0177] Table 2 lists the analysis results for each peak after peak separation, as well as the overall molecular weight and distribution for the analysis of all peaks as a whole. The high molecular weight peak proportion refers to the percentage of the peak area with a weight-average molecular weight greater than 500,000 g / mol relative to the total peak area. As can be seen in Table 2, multiple peaks were present in all examples, and the weight-average molecular weight of the graft copolymers with higher molecular weights was greater than 1,000,000 g / mol, with an overall molecular weight greater than 130,000 g / mol.

[0178] Test Example 2

[0179] The polymers in some examples and comparative examples were subjected to melt stretching tests at 235° C. to characterize their melt strength. The test results are shown in Table 3.

[0180] Table 3

[0181] Melt strength (cN) Example 1 5 Example 2 5 Example 3 18 Example 4 9 Comparative Example 1 3 Comparative Example 2 0.3 Comparative Example 3 1

[0182] As shown in Table 3, the polyester compositions obtained in the present invention (Examples 1-4) exhibit significantly higher melt strength than the polyester homopolymers (Comparative Examples 1-3). The melt strength increased from 0.3 cN (Comparative Example 2) to 18 cN (Example 3), a 60-fold increase, fully demonstrating the unique and unexpectedly high melt strength of the polyester compositions of the present invention.

[0183] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A polyester composition, characterized in that The composition comprises a polyester graft copolymer and a polyester homopolymer, wherein the main chain of the polyester graft copolymer contains a structural unit A1 represented by formula (A1), the graft chain segment of the polyester graft copolymer is a polyester chain segment, and the average polymerization degree of the graft chain segment is not less than 150; In formula (A1): The subscript i is an arbitrary integer not less than 1 and not greater than 10; R is independently hydrogen or C1-C 30 organic groups, X is independently C1 to C 15 organic groups; * indicates the attachment site to which the grafted chain segments in the polyester graft copolymer are attached.

2. The composition according to claim 1, wherein In formula (A1), X is independently selected from C1 to C 15 Substituted or unsubstituted alkylene, C2~C 15 Substituted or unsubstituted alkyleneoxy or C6~C 15 a substituted or unsubstituted arylene group; and / or, In formula (A1): R is independently hydrogen, C1 to C 30 Substituted or unsubstituted hydrocarbon groups, C2~C 30 Substituted or unsubstituted alkoxy, C6~C 30 Substituted or unsubstituted aromatic group or C6~C 30 a substituted or unsubstituted alkylhydroxyl group; and / or, The main chain of the polyester graft copolymer contains a structural unit A2 represented by formula (A2); In formula (A2), X, R, and i are defined the same as those in formula (A1); Preferably, The sum of the degrees of polymerization of structural unit A1 and structural unit A2 is not less than 15, preferably 15 to 4000, more preferably 40 to 385; and / or, Based on the sum of the degrees of polymerization of structural unit A1 and structural unit A2, the degree of polymerization of structural unit A2 accounts for 0.1% to 80%, preferably 10% to 40%; and / or In the polyester graft copolymer, the average polymerization degree of the grafted chain segment is not less than 200, more preferably 300 to 3000, and even more preferably 400 to 2000.

3. The polyester composition according to claim 1 or 2, wherein The main chain of the polyester graft copolymer contains a structural unit A3 represented by formula (A3), In formula (A3), T1, T2, T3 and T4 are each independently hydrogen or C1-C 30 organic groups; Preferably, in formula (A3), T1, T2, T3 and T4 are each independently hydrogen, C1 to C 30 Substituted or unsubstituted hydrocarbon groups, C2~C 30 Substituted or unsubstituted alkoxy, C6~C 30 Substituted or unsubstituted aromatic group or C6~C 30 a substituted or unsubstituted alkylhydroxyl group; and / or, Based on the total degree of polymerization of all structural units in the main chain of the polyester graft copolymer, the proportion of the degree of polymerization of the structural unit A3 is no more than 50%.

4. The polyester composition according to claim 3, wherein The structural formula of the polyester graft copolymer is shown in formula (A), In formula (A): x1, ..., x i ,y1,y2,……,y i and z each independently represent the degree of polymerization; PM1, ..., PM i represents a polyester segment and the corresponding polymerization degrees of the polyester segments are p1, ..., p i ; x1, ..., x i and z are each independently zero or greater than zero, and x 1、 ..., x i are not all 0 at the same time; y1, ..., y i、 p1, ..., p i Each independently represents a number greater than zero; the subscript i in the degree of polymerization is an arbitrary integer not less than 1 and not greater than 10; z accounts for x1+……+x i +y1+……+y i The ratio of the sum of +z is 0% to 50%.

5. The composition according to any one of claims 1 to 4, wherein The graft segments of the polyester graft copolymer and the polyester segments of the polyester homopolymer in the composition are simultaneously derived from hydroxy acid monomers or derivatives of hydroxy acid monomers; Preferably, the graft segments of the polyester graft copolymer and the polyester segments of the polyester homopolymer in the composition are derived from lactide monomers and / or lactone monomers; More preferably, the lactide monomer is an α-hydroxy acid-based or β-hydroxy acid-based lactide monomer, preferably the lactide monomer is selected from one or more of methyl glycolate, glycolic acid, glycolide, lactide, butyrolactone, valerolactone and hexyl lactide; and / or, the lactone monomer is selected from β-butyrolactone, δ-valerolactone, ε-caprolactone, β-propiolactone, β-valerolactone, γ-butyrolactone, γ-valerolactone, γ-octalactone, β-methyl-δ-valerolactone, δ-stearolactone, 2-methyl-ε-caprolactone, 4-methyl-ε-caprolactone, one or more of ε-palmitolactone in ε-octalactone, preferably the lactone monomer is selected from one or more of β-butyrolactone, δ-valerolactone and ε-caprolactone; More preferably, the graft segments of the polyester graft copolymer and the polyester segments of the polyester homopolymer in the composition are derived from one or more of methyl glycolate, glycolic acid and glycolide.

6. The composition according to any one of claims 1 to 5, wherein The polyester homopolymer contains polyester segments in the polyester graft copolymer; Preferably, the polyester homopolymer contains a small molecule initiator segment (M) provided by a small molecule initiator. j , j is any integer between 1 and 20, preferably any integer between 1 and 6; M is each an imino group, a secondary amino group or an ether bond; and / or, The polyester homopolymer contains an end-capping group R, wherein R is hydrogen, an aliphatic group or an aromatic group, preferably hydrogen, an alkyl group or an aromatic hydrocarbon group having a molecular weight of 14 to 1000 g / mol; and / or, The sum of the polymerization degrees of the polyester segments in the polyester homopolymer is 100 to 5000, preferably 1000 to 4000; The structural formula of the polyester homopolymer is shown in formula (II), In formula (II): j is directly connected to R The number of, j ≥ 1, preferably j is any integer between 1 and 20, preferably any integer between 1 and 6; M1, ..., M j Each is an imino group, a nitro group or an ether bond; R is at least one of hydrogen, an aliphatic group or an aromatic group, preferably hydrogen, an alkyl group or an aromatic hydrocarbon group having a molecular weight of 14 to 1000 g / mol; PM1, PM2. j represents a polyester segment and the corresponding polymerization degrees of the polyester segments are p1, ..., p j ; More preferably, the structural formula of the polyester homopolymer is as shown in formula (III), In formula (III): j is directly connected to R The number of, j ≥ 1, preferably j is any integer between 1 and 20, preferably any integer between 1 and 6; M1, ..., M j The definition of M1, ..., M in formula (II) j The same definition as; n1,……,n j Each is the degree of polymerization; n1,……,n j The sum is 100 to 5000, preferably 1000 to 4000.

7. The composition according to claim 6, wherein The polymer composition contains 0.001 to 10 parts by mass, preferably 0.005 to 3 parts by mass, more preferably 0.01 to 1 part by mass of the polyester graft copolymer and the polyester segment in the polyester homopolymer. and containing 0.001 to 1 parts by mass, preferably 0.01 to 0.1 parts by mass x1, ..., x i ,y1,……,y i and z each independently represent the degree of polymerization; PM1, ..., PM i represents a polyester segment and the corresponding polymerization degrees of the polyester segments are p1, ..., p i ; x1, ..., x i and z are each independently zero or greater than zero, and x 1、 ..., x i are not all 0 at the same time; y1, ..., y i、 p1, ..., p i Each of them is independently a number greater than zero; the subscript i is an integer not less than 1 and not greater than 10; z occupies x1+……+x i +y1+……+y i +z sum ratio is 0% to 50%; and / or, Relative to the total mass of the polyester graft copolymer and the polyester homopolymer, the content of the polyester graft copolymer is 0.1% by mass to 80.0% by mass, preferably 0.5% by mass to 55.0% by mass, and more preferably 1.0% by mass to 30.0% by mass; and / or the content of the polyester homopolymer is 20% by mass to 99.9% by mass, preferably 45.0% by mass to 99.5% by mass, and more preferably 70.0% by mass to 99.0% by mass.

8. The composition according to any one of claims 1 to 7, wherein The total weight average molecular weight of the composition is 120,000 to 1.5 million g / mol, preferably 160,000 to 1 million g / mol, more preferably 200,000 to 500,000 g / mol; and / or, The overall molecular weight polydispersity index of the composition is 1.5 to 20.0, preferably 2.0 to 12.0, more preferably 2.0 to 6.0, and even more preferably 2.0 to 3.5; and / or, The molecular weight polydispersity index of the polyester graft copolymer is 1.0 to 3.0, preferably 1.1 to 1.5; and / or, The molecular weight polydispersity index of the polyester homopolymer is 1.0 to 3.0, preferably 1.4 to 2.

5.

9. The composition according to any one of claims 1 to 8, wherein The molecular weight of the composition is multimodal, and preferably the number of peaks in the molecular weight distribution of the composition is 2 to 4; preferably, The peak molecular weight M in the molecular weight distribution curve of the composition p The number of peaks greater than 500,000 g / mol is at least 1, and the peak molecular weight M p The number of peaks with a value less than 500,000 g / mol is at least one; and / or, The molecular weight of the polyester graft copolymer is higher than that of the polyester homopolymer. Preferably, the weight average molecular weight of the polyester graft copolymer is 500,000 to 10 million g / mol, preferably 1 million to 7 million g / mol, more preferably 1 million to 6 million g / mol; and / or, the weight average molecular weight of the polyester homopolymer is 50,000 to 350,000 g / mol, preferably 100,000 to 200,000 g / mol; and / or, The melt strength of the composition at 235° C. is not less than 4 cN and not more than 200 cN, preferably not less than 8 cN and not more than 100 cN.

10. A method for preparing the polyester composition according to any one of claims 1 to 9, characterized in that: The preparation method comprises: melt-polymerizing a polymer raw material containing a macromolecular initiator and a polyester monomer capable of providing a structural polyester chain segment; Wherein, the macromolecular initiator contains structural units The definitions of X, R, and i are the same as those of X, R, and i in any one of claims 1 to 9.

11. The method for preparing the polyester composition according to claim 10, wherein: The macroinitiator contains a structural unit A3 represented by formula (A3), In formula (A3), T1, T2, T3 and T4 are each independently hydrogen or C1-C 30 an organic group; and / or, The polymeric raw material also contains a small molecule initiator, j is an integer greater than or equal to 1, M1, ..., M j Each is an imino group, a nitro group or an ether bond, and R is at least one of hydrogen, an aliphatic group or an aromatic group.

12. The preparation method according to claim 11, wherein The weight average molecular weight of the macroinitiator is 2000 to 500000 g / mol, preferably 5000 to 50000 g / mol; and / or, The small molecule initiator is selected from water and / or a small molecule compound containing hydroxyl groups and / or amino groups with a boiling point greater than 160° C., preferably, the molecular weight of the small molecule compound containing hydroxyl groups and / or amino groups is not greater than 1000 g / mol; preferably 60 to 300 g / mol; and / or, The content of hydroxyl groups contained in the macroinitiator is 0.1 μmol / g monomer to 1.5 mmol / g monomer, preferably 0.5 μmol / g monomer to 1.0 mmol / g monomer, more preferably 1.0 μmol / g monomer to 0.5 mmol / g monomer, per gram of polyester monomer, calculated as hydroxyl groups; and / or The active hydrogen content of the small molecule initiator is 3.0 μmol / g monomer to 40.0 μmol / g monomer, preferably 10.0 μmol / g monomer to 30.0 μmol / g monomer, calculated as active hydrogen per gram of polyester monomer; and / or Based on mass, the amount of the macroinitiator is 0.001 to 10 parts by mass, preferably 0.005 to 3 parts by mass, more preferably 0.01 to 1 part by mass, relative to 100 parts by mass of the polyester monomer; and / or, In terms of mass, the amount of the small molecule initiator used is 0.001 to 1 part by mass, preferably 0.01 to 0.1 part by mass, relative to 100 parts by mass of the polyester monomer.

13. The preparation method according to any one of claims 10 to 12, wherein The conditions of the melt polymerization include: a temperature of 120 to 300° C., preferably 160 to 250° C., more preferably 200 to 240° C.; and / or a reaction time of 0.5 to 60 min, preferably 1 to 10 min; and / or, The melt polymerization is carried out in a melt mixing device; preferably, the melt polymerization is carried out in a continuous twin-screw extruder, and the polymerization reaction conditions of the continuous twin-screw extruder preferably include: a temperature of 180 to 250° C., preferably 210 to 240° C.; and / or a screw speed of 5 to 300 rpm, preferably 40 to 150 rpm; and / or an aspect ratio of 25 to 80, preferably 40 to 70; and / or The melt polymerization is carried out in the presence of a catalyst and optionally an antioxidant. Preferably, the catalyst is selected from a salt compound of at least one of Group IIA metal elements, Group IIIA metal elements, Group IVA metal elements, Group VA metal elements and transition metal elements, or an organic guanidine catalyst; preferably, the amount of the catalyst is 0.005 to 1 part by mass, preferably 0.01 to 0.2 parts by mass, relative to 100 parts of monomer.

14. A polyester composition prepared by the method according to any one of claims 10 to 13.

15. An article prepared from a raw material comprising the polyester composition according to any one of claims 1 to 9 and 14; Preferably, the article is selected from films, rods, tubes, wires, sheets or shaped parts.

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