Polymer and method for producing polymer

Abstract

To provide a polymer having a polyolefin structure of a branch structure of a polymer obtained by polymerizing a cyclic ketene acetal and an olefin or the like and a method for producing the same.SOLUTION: There is provided a polymer containing a structural unit represented by the formula (1-A) and a structural unit represented by the formula (1-B) and having a weight-average molecular weight (Mw) of 20000 to 1000000. [l and m represents an integer satisfying 0.01≤l / (l+m)≤0.20, m represents an integer of 1 to 3, R1 and R2 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, Z contains a structure represented by the formula (2). In the formula (2), R3 and R6 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, at least one of R3 to R6 contained in m Z groups is a hydrocarbon group having 2 to 20 carbon atoms which may have a substituent.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to polymers and methods for making polymers. [Background technology]

[0002] Polyolefin polymers such as polyethylene are polymers that have excellent weather resistance, chemical resistance, and mechanical properties, and many products containing polyolefin polymers are used in our daily lives. In particular, polyethylene polymers are used as packaging materials for food, electronic components, and various everyday items due to their stability and light weight, thereby enriching our daily lives.

[0003] However, due to its stability, polyethylene polymers are hardly decomposed even when physically reduced to the smallest possible size. Therefore, if polyethylene polymers are disposed of in landfills, they will remain in the ground semi-permanently. Furthermore, if polyethylene polymers are dumped, they may become marine litter and have a negative impact on marine life.

[0004] Therefore, in order to reuse polyolefin polymers such as polyethylene contained in waste materials, a chemical recycling method is used in which raw material monomers obtained by decomposing the polyolefin polymers are reused. However, due to the large molecular weight of many polyolefin polymers, a huge amount of energy is required to decompose them into the original raw material monomers. Therefore, among chemical recycling methods, thermal recycling is used, but this method inevitably generates carbon dioxide and has a large environmental impact, so it is not a preferable method from the viewpoint of global environmental conservation.

[0005] Therefore, polyolefin polymers that can be easily chemically recycled without placing a burden on the environment have been proposed. For example, Patent Documents 1 to 5 and Non-Patent Documents 1 and 2 disclose polyolefin polymers that contain structural units derived from ketene acetal in the main chain. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 04-081450 [Patent Document 2] Japanese Patent Application Publication No. 58-015508 [Patent Document 3] Japanese Patent Application Publication No. 04-081450 [Patent Document 4] Special Publication No. 06-504086 [Patent Document 5] U.S. Patent No. 5,281,681 [Non-patent literature]

[0007] [Non-Patent Document 1] iScience.,Volume23,Issue3,27 / March / 2020,100904 [Non-patent document 2] J.Environ.Polym.Degrad.,Volume6,p23-29(1998) Summary of the Invention [Problem to be solved by the invention]

[0008] In the polyolefin polymers described in the above documents, which contain structural units derived from cyclic ketene acetals in the main chain, the polyolefins specified have a linear structure. In order to improve the moldability of the polymer, a polymer in which the polyolefin chain has a branched structure is desired. Meanwhile, the present inventors have conducted research and found that in all of the methods described in the above documents, raw materials are polymerized under ultra-high pressure. Although it is described that polyethylene having a linear structure can be obtained by polymerizing cyclic ketene acetal and ethylene under ultra-high pressure, there is no mention of a branched structure. Under these circumstances, an object of the present invention is to provide a polymer having a branched structure, such as a polymer obtained by polymerizing a cyclic ketene acetal and an olefin and having a branched polyolefin structure, as well as a method for producing the same. [Means for solving the problem]

[0009] In view of the above-mentioned problems, the present inventors have conducted research and found that the above-mentioned problems can be solved by heating a radical polymerizable monomer and a cyclic ketene acetal in the presence of a radical polymerization initiator under a pressure of 1 MPa to 20 MPa. Specifically, the above problems were solved by the following means. [1] A polymer containing a structural unit represented by formula (1-A) and a structural unit represented by formula (1-B), and having a weight average molecular weight (Mw) of 20,000 to 1,000,000. [ka] (In formula (1-A) and formula (1-B), l and m represent integers satisfying 0.01≦l / (l+m)≦0.20, and n represents an integer of 1 to 3. 1 and R 2 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. 1 and R 2 may be bonded to each other to form a cyclic structure. Z includes a structure represented by formula (2). [ka] (In formula (2), R 3 ~R 6 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. 3 ~R 6 At least one of them is a hydrocarbon group having 2 to 20 carbon atoms which may have a substituent.) [2] In the formula (2), R 3 ~R 6at least one of which is a linear alkyl group having 2 to 20 carbon atoms which may have a substituent, a branched alkyl group having 3 to 20 carbon atoms which may have a substituent, or a cycloalkyl group having 3 to 20 carbon atoms which may have a substituent. [3] The polymer according to [1] or [2], wherein the constitutional unit represented by the formula (1-A) is derived from a radical polymerizable monomer. [4] The polymer according to [3], wherein the radical polymerizable monomer comprises at least one selected from the group consisting of ethylene and olefins having 3 to 12 carbon atoms. [5] The polymer according to any one of [1] to [4], wherein the constitutional unit represented by the formula (1-B) is derived from a cyclic ketene acetal. [6] The polymer according to [5], wherein the cyclic ketene acetal is represented by formula (3): [ka] (In formula (3), R 1 and R 2 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. 1 and R 2 may be bonded to each other to form a cyclic structure, and n represents an integer of 1 to 3. [7] The polymer according to [5], wherein the cyclic ketene acetal is represented by formula (4): [ka] (In formula (4), R 1 and R 2 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. 1 and R 2 may be bonded to each other to form a cyclic structure. [8] The polymer according to any one of [1] to [7], wherein the structural unit represented by formula (1-A) and the structural unit represented by formula (1-B) are, respectively and independently, a structural unit represented by formula (1-A-2) and a structural unit represented by formula (1-B-2). [ka] (In formula (1-A-1) and formula (1-B-2), l and m represent integers satisfying the condition 0.01≦l / (l+m)≦0.20. R 3 ~R 6 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. 3 ~R 6 At least one of them is a hydrocarbon group having 2 to 20 carbon atoms which may have a substituent.) [9] A method for producing a polymer containing a structural unit represented by formula (1-A) and a structural unit represented by formula (1-B), the method comprising: polymerizing at least a radically polymerizable monomer and a cyclic ketene acetal by heating under a pressure of 1 MPa to 20 MPa in the presence of a radical polymerization initiator. [ka] (In formula (1-A) and formula (1-B), l and m represent integers satisfying 0.01≦l / (l+m)≦0.20, and n represents an integer of 1 to 3. 1 and R 2 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. 1 and R 2 may be bonded to each other to form a cyclic structure. Z includes a structure represented by formula (2). [ka] (In formula (2), R 3 ~R 6 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. 3 ~R 6 At least one of them is a hydrocarbon group having 2 to 20 carbon atoms which may have a substituent.)

[10] The method for producing a polymer according to [9], wherein the radical polymerizable monomer comprises at least one selected from the group consisting of ethylene and olefins having 3 to 12 carbon atoms.

[11] The method for producing a polymer according to [9] or

[10] , wherein the cyclic ketene acetal is represented by formula (3): [ka] (In formula (3), R 1 and R 2 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. 1 and R 2 may be bonded to each other to form a cyclic structure, and n represents an integer of 1 to 3.

[12] The method for producing a polymer according to any one of [9] to

[11] , wherein the cyclic ketene acetal is represented by formula (4): [ka] (In formula (4), R 1 and R 2 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. 1 and R 2 may be bonded to each other to form a cyclic structure.

[13] The method for producing a polymer according to any one of [9] to

[12] , wherein the heating temperature during the polymerization is 60 to 85°C.

[14] The method for producing a polymer according to any one of [9] to

[13] , further comprising heating the polymer obtained by heating at 60 to 85°C at 170 to 250°C under reduced pressure in the presence of a metal catalyst to further increase the molecular weight.

[15] The method for producing a polymer according to any one of [9] to

[14] , comprising hydrolyzing the polymer obtained by heating at 60 to 85°C, and then heating it at 170 to 250°C under reduced pressure in the presence of a metal catalyst to further increase the molecular weight.

[16] The method for producing a polymer according to

[15] , wherein the hydrolysis is carried out by heating in an alcoholic solvent at 130 to 200°C in the presence of a basic catalyst.

[17] A method for producing a polymer comprising a structural unit represented by formula (1-A) and a structural unit represented by formula (1-B), the method comprising heating an oligomer represented by formula (3) to polycondense the polymer. [ka] (In formula (3), n represents an integer of 1 to 3. mp represents an integer of 4 to 99. R 1 and R 2 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. 1 and R 2 may be bonded to each other to form a cyclic structure. Z includes a structure represented by formula (2). [ka] (In formula (2), R 3 ~R 6 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. 3 ~R 6 At least one of them is a hydrocarbon group having 2 to 20 carbon atoms which may have a substituent.) [ka] (In formula (1-A) and formula (1-B), l and m represent integers satisfying 0.01≦l / (l+m)≦0.20, and n represents an integer of 1 to 3. 1 and R 2 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. 1 and R 2 may be bonded to each other to form a cyclic structure. Z includes a structure represented by formula (2). [ka] (In formula (2), R 3 ~R 6 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. 3 ~R 6 At least one of them is a hydrocarbon group having 2 to 20 carbon atoms which may have a substituent.)

[18] A method for producing a polymer according to

[17] , comprising obtaining the oligomer represented by formula (3) by hydrolyzing a polymer (A) comprising a structural unit represented by formula (1-A) and a structural unit represented by formula (1-B). [ka] (In formula (1-A) and formula (1-B), l and m represent integers satisfying 0.01≦l / (l+m)≦0.20, and n represents an integer of 1 to 3. 1 and R 2 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. 1 and R 2 may be bonded to each other to form a cyclic structure. Z includes a structure represented by formula (2). [ka] (In formula (2), R 3 ~R 6 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. 3 ~R 6 At least one of them is a hydrocarbon group having 2 to 20 carbon atoms which may have a substituent.)

[19] The method for producing a polymer according to

[18] , wherein the polymer (A) includes a recycled product.

[20] The method for producing a polymer according to

[18] or

[19] , wherein the hydrolysis is carried out by heating in an alcoholic solvent at 130 to 200°C in the presence of a basic catalyst.

[21] The method for producing a polymer according to any one of

[17] to

[20] , wherein the oligomer represented by the formula (3) is heated to a temperature of 60 to 85°C.

[22] The polymer obtained by heating at 60 to 85 ° C. and further heating the polymer at 170 to 250°C under reduced pressure in the presence of a metal catalyst to further increase the molecular weight. [Effects of the Invention]

[0010] The present invention makes it possible to provide a polymer having a branched structure and a method for producing the same. For example, it has become possible to provide a polymer obtained by polymerizing a cyclic ketene acetal and an olefin, which has a branched polyolefin structure, as well as a method for producing the same. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment for carrying out the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. Note that the present embodiment is an example for explaining the present invention, and the present invention is not limited to only this embodiment. In this specification, the symbol "to" is used to mean that the numerical values ​​before and after it are included as upper and lower limits. "A to B" means that the range is A or more and B or less. In addition, any combination of the upper and lower limit values ​​of the numerical values ​​in this specification is an example of this embodiment.

[0012] In this specification, "mol %" indicates the content ratio of a specific component contained in a total amount of 100 mol %. Furthermore, "mol %" and "wt %" have the same meaning.

[0013] As used herein, "optional" or "optionally" means that the subsequently described circumstance may or may not occur, and thus the description includes both the occurrence and non-occurrence of the circumstance.

[0014] In this specification, the term "structural unit" refers to a unit derived from a raw material compound used in the production of a polymer, formed by polymerization of the raw material compound, and a partial structure sandwiched between any linking groups in the resulting polymer. It also includes a partial structure at the terminal portion of a polymer, one of which is a linking group and the other of which is a polymerization reactive group. The structural unit may be a unit formed directly by the polymerization reaction, or may be a unit in which a portion of the unit is converted into a different structure by treating the resulting polymer.

[0015] In the general formulas herein, C represents a carbon atom, H represents a hydrogen atom, and O represents an oxygen atom. In this specification, various physical properties and characteristic values ​​are those at 23°C unless otherwise specified. In the description of groups (atomic groups) in this specification, when a notation does not specify whether they are substituted or unsubstituted, it includes both groups (atomic groups) that have no substituents and groups (atomic groups) that have substituents. For example, the term "alkyl group" includes not only alkyl groups that have no substituents (unsubstituted alkyl groups) but also alkyl groups that have substituents (substituted alkyl groups). In this specification, when a notation does not specify whether they are substituted or unsubstituted, it is preferable that they be unsubstituted. Examples of the substituent herein include, preferably, a halogen atom, a cyano group, a nitro group, a hydroxy group, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, a heterocyclic group, a heterocyclic oxy group, an alkenyl group, an alkylsulfanyl group, an arylsulfanyl group, an acyl group, or an amino group; more preferably, a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an alkenyl group, or an acyl group; even more preferably, an alkyl group, an aryl group, an aryloxy group, or an alkenyl group; and even more preferably, an alkyl group. The formula weight of these substituents is preferably 15 or more and preferably 200 or less. For example, the formula weight of a methyl group (-CH3) is 15. These substituents may further have a substituent, but it is preferable that they have no substituent.

[0016] As used herein, the term "step" includes not only an independent step but also a step that cannot be clearly distinguished from other steps, as long as the intended effect of the step is achieved. All steps described herein can be performed in any suitable order unless otherwise specified in the specification or clearly contradicted by the context. If the measurement methods, etc. described in the standards shown in this specification change from year to year, they will be based on the standards in effect as of January 1, 2024, unless otherwise specified. If the measurement methods, etc. described in the standards shown in this specification are abolished as of January 1, 2024, they will be based on the standards in effect at the time of abolition.

[0017] Hereinafter, the embodiments of the present invention will be described in detail. However, the explanation of the constituent elements described below is an example of an embodiment of the present invention, and the present invention is not limited to these contents.

[0018] [Polymer] The polymer of this embodiment is characterized by containing a structural unit represented by formula (1-A) and a structural unit represented by formula (1-B) and having a weight-average molecular weight (Mw) of 20,000 to 1,000,000. In this specification, a "polymer containing a structural unit represented by formula (1-A) and a structural unit represented by formula (1-B)" may be referred to as a "polymer (A)." Therefore, even a polymer that falls under the category of polymer (B) described below is included in polymer (A) as long as it has a weight-average molecular weight (Mw) of 20,000 to 1,000,000. [ka] (In formula (1-A) and formula (1-B), l and m represent integers satisfying 0.01≦l / (l+m)≦0.20, and n represents an integer of 1 to 3. 1 and R 2 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. 1 and R 2 may be bonded to each other to form a cyclic structure. Z includes a structure represented by formula (2). [ka] (In formula (2), R 3 ~R 6 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. 3 ~R 6 At least one of them is a hydrocarbon group having 2 to 20 carbon atoms which may have a substituent.)

[0019] In formula (1-A) and formula (1-B), l and m represent integers that satisfy the relationship 0.01≦l / (l+m)≦0.20, where l and m are molar ratios. Furthermore, the lower limit of the ratio l / (l+m) is preferably 0.01 or more, more preferably 0.015 or more, even more preferably 0.02 or more, and even more preferably 0.03 or more. On the other hand, the upper limit of l / (l+m) is not particularly limited, and from the viewpoint of the mechanical strength and heat resistance of the obtained polymer (B), it is preferably 0.20 or less, more preferably 0.17 or less, more preferably 0.15 or less, and even more preferably 0.13 or less. The upper and lower limits can be combined in any manner. For example, the (l / (l+m)) is preferably 0.01 or more and 0.20 or less, more preferably 0.015 or more and 0.17 or less, even more preferably 0.02 or more and 0.15 or less, and even more preferably 0.03 or more and 0.13 or less.

[0020] The above l is preferably an integer of 1 to 15, and more preferably an integer of 1 to 10. The above m is preferably an integer of 85 to 99, and more preferably an integer of 90 to 99. The n represents an integer of 1 to 3. When n is 2 or 3, a plurality of R 1 and R 2 If there are multiple R 1 may be the same or different, and multiple R 2 may be the same or different. n is preferably 2.

[0021] R1 and R 2 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. 1 and R 2 may be bonded to each other to form a ring structure. R 1 and R 2 each independently represents a hydrogen atom, an optionally branched alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms which may have a substituent, an optionally branched aryl group having 6 to 10 carbon atoms, or an optionally substituted aralkyl group having 7 to 10 carbon atoms, and is preferably a hydrogen atom or an optionally branched alkyl group having 1 to 10 carbon atoms, and more preferably a hydrogen atom. Also, R 1 and R 2 At least one of R may contain at least one heteroatom selected from the group consisting of oxygen, sulfur, and nitrogen atoms. 1 and R 2 Preferably, does not contain heteroatoms. Adjacent R 1 and R 2 may be bonded to each other to form a ring structure. For example, R 1 and R 2 are bonded to each other to form a benzomethylene structure.

[0022] R 1 and R 2 The alkyl group is preferably an alkyl group having 1 to 5 carbon atoms, which may be branched. R 1 and R 2 The cycloalkyl group is preferably a cycloalkyl group having 3 to 5 carbon atoms which may have a substituent.

[0023] R 1 and R 2 Examples of the substituent that the cycloalkyl group, aryl group, and aralkyl group may have include an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and the like.

[0024] R 1 and R 2 Examples of the alkyl group having 1 to 10 carbon atoms, which may have a branch, include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, an n-hexyl group, and a 2-ethylhexyl group.

[0025] R 1 and R 2 Examples of the cycloalkyl group having 3 to 10 carbon atoms (if the cycloalkyl group has a substituent, the number of carbon atoms of the substituent is not included in this number of carbon atoms) which may have a substituent include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group.

[0026] R 1 and R 2 Examples of the aryl group having 6 to 10 carbon atoms (if the aryl group has a substituent, the number of carbon atoms of the substituent is not included in this number of carbon atoms) which may have a substituent include a phenyl group, an o-methylphenyl group, an m-methylphenyl group, a p-methylphenyl group, a p-tert-butylphenyl group, and a p-methoxyphenyl group.

[0027] R 1 and R 2 Examples of the optionally substituted aralkyl group having 7 to 10 carbon atoms (if the aralkyl group has a substituent, this carbon number does not include the number of carbon atoms of the substituent) include a benzyl group and a phenylethyl group.

[0028] The above R other than hydrogen atoms 1 and R 2 As the alkyl group, a methyl group, a tert-butyl group, a cyclohexyl group, and a phenyl group are preferred, and a methyl group is more preferred.

[0029] The Z includes a structure represented by formula (2). That is, Z may have only the structure represented by formula (2), or may have other structures. Z is preferably a structure represented by formula (2), or a combination of a structure represented by formula (2) and a structure selected from the group consisting of -C(=O)-, -O-, a structural unit derived from a diene which may contain a heteroatom, and a structural unit derived from a compound having a vinyl bond. Preferably, Z has a repeating unit having at least one alkyl group having 1 to 20 carbon atoms, which may be branched, and at least one cycloalkyl group having 3 to 20 carbon atoms, which may be substituted, on the side chain, and more preferably has a repeating unit having at least one alkyl group having 1 to 20 carbon atoms, which may be branched, on the side chain. By having a repeating unit with such a branched structure, a polymer (A) having better transparency and strength tends to be obtained. Here, the side chain refers to, for example, a group bonded to a carbon atom in the main chain of a polymer formed from a carbon-carbon double bond possessed by a radical polymerizable monomer. When there are two or more polymer chains formed from a carbon-carbon double bond possessed by a radical polymerizable monomer, the longest chain is considered to be the main chain.

[0030] The proportion of the structure represented by formula (2) in the Z is preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 90 mol% or more, still more preferably 95 mol% or more, and even more preferably 99 mol% or more, and may be 100 mol%, when the total amount of Z contained in the polymer (A) of the present embodiment is 100 mol%.

[0031] In formula (2), R 3 ~R 6 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. 3 ~R 6At least one of Z is a hydrocarbon group having 2 to 20 carbon atoms which may have a substituent. 3 ~R 6 Among the m Z's contained in the polymer of the present embodiment, R 3 ~R 6 The ratio of at least one of the hydrocarbon groups having 2 to 20 carbon atoms, which may have a substituent, to the number of carbon atoms in the main chain of 1,000 (R 3 ~R 6 is bonded to), the number of carbon atoms is preferably 10 or more, more preferably 15 or more, and preferably 50 or less, more preferably 45 or less. These upper and lower limits can be arbitrarily combined, and are preferably 10 or more and 50 or less, and more preferably 15 or more and 45 or less. The number of carbon atoms in the 1,000 main chain is measured as described in the Examples below. In addition, in the polymer of this embodiment, R of Z 3 ~R 6 It is preferable that a structure in which the moiety corresponding to the following is a methyl group is not detected when measured by the method described in the Examples below.

[0032] R 3 ~R 6 R each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. 3 ~R 6 Adjacent two of these may be bonded to each other to form a cyclic structure.

[0033] R 3 ~R 6each independently represents a hydrogen atom, an optionally branched alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an optionally substituted aryl group having 6 to 20 carbon atoms, or an optionally substituted aralkyl group having 7 to 10 carbon atoms; more preferably a hydrogen atom, an optionally substituted linear alkyl group having 2 to 20 carbon atoms, an optionally substituted branched alkyl group having 3 to 20 carbon atoms, or an optionally substituted cycloalkyl group having 3 to 20 carbon atoms; and even more preferably a optionally substituted linear alkyl group having 2 to 20 carbon atoms, or an optionally substituted branched alkyl group having 3 to 20 carbon atoms. In the formula (2), R 3 ~R 6 At least one of them is preferably a linear alkyl group having 2 to 20 carbon atoms which may have a substituent, a branched alkyl group having 3 to 20 carbon atoms which may have a substituent, or a cycloalkyl group having 3 to 20 carbon atoms which may have a substituent, and more preferably a linear alkyl group having 2 to 20 carbon atoms which may have a substituent, or a branched alkyl group having 3 to 20 carbon atoms which may have a substituent. Also, R 3 ~R 6 At least one of R may contain at least one heteroatom selected from the group consisting of oxygen, sulfur, and nitrogen atoms. 3 ~R 6 Preferably, the group does not contain heteroatoms.

[0034] The optionally substituted linear alkyl group having 2 to 20 carbon atoms is preferably an ethyl group, a butyl group, a hexyl group, an octyl group, a decanyl group, a dodecanyl group, a tetradecanyl group, a hexadodenyl group, an octadodenyl group, or an icosanyl group. The branched alkyl group having 3 to 20 carbon atoms which may have a substituent is more preferably a 2-ethylhexyl group or a 2-ethylbutyl group. The optionally substituted cycloalkyl group having 3 to 20 carbon atoms is preferably a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, or a cyclooctyl group. Z in the present polymer preferably has a branched structure portion represented by structural formula (Y). [ka] (In structural formula (Y), C a , C b , C c represents the methylene carbon adjacent to the branch carbon, and C br represents the methine carbon at the base of the branched chain, and P 1 , P 2 , P 3 represents a polymer residue.

[0035] In the polymer of this embodiment, the constitutional unit represented by formula (1-A) is preferably derived from a radically polymerizable monomer. The radical polymerizable monomer is preferably a radical polymerizable monomer that does not have a carbon-carbon double bond or a reactive functional group in the side chain when copolymerized. In this embodiment, the radical polymerizable monomer is preferably an olefin, more preferably an α-olefin. In this embodiment, when the total amount of structural units represented by formula (1-A) contained in polymer (A) of this embodiment is taken as 100 mol %, the proportion of structural units derived from a radically polymerizable monomer (preferably an olefin, more preferably an α-olefin) is preferably 50 mol % or more, more preferably 70 mol % or more, even more preferably 90 mol % or more, even more preferably 95 mol % or more, even more preferably 99 mol % or more, and may be 100 mol %.

[0036] The radical polymerizable monomer is not particularly limited, and examples thereof include vinyl aromatic hydrocarbons such as styrene, α-methylstyrene, p-methylstyrene, and m-methylstyrene; vinyl alicyclic hydrocarbons such as vinylcyclohexane, vinylcyclopentane, vinylcyclohexene, vinylcycloheptane, vinylcycloheptane, and vinylnorbornane; ethylenically unsaturated carboxylic acids such as maleic anhydride, maleic acid, and itaconic acid; olefins having 2 to 12 carbon atoms such as ethylene, propylene, 1-butene, isobutylene, 1-pentene, 1-hexene, 1-octene, 1-decene, and 1-dodecene; conjugated dienes such as butadiene, isoprene, and myrcene; acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, vinyl acetate, vinyl ketone, and vinyl chloride. vinylidene chloride, vinylidene fluoride; (meth)acrylic acid alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, amyl (meth)acrylate, isoamyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, pentadecyl (meth)acrylate, and dodecyl (meth)acrylate; (meth)acrylic acid derivatives such as 2-hydroxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, glycidyl (meth)acrylate, allyl (meth)acrylate, and benzyl (meth)acrylate;2-vinylfuran, 2-isopropenylfuran, 2-vinylbenzofuran, 2-isopropenylbenzofuran, 2-vinyldibenzofuran, 2-vinylthiophene, 2-isopropenylthiophene, 2-vinyldibenzothiophene, 2-vinylpyrrole, N-vinylindole, N-vinylcarbazole, 2-vinyloxazole, 2-isopropenyloxazole, 2-vinylbenzoxazole, 3-vinylisoxazole, 3-isopropenylisoxazole, 2-vinylthiazole, 2-vinylimidazole, 4(5)-vinylimidazole, N-vinylimidazole, N-vinylimidazoline, 2-vinylbenzimidazole, 5(6)-vinylbenzimidazole, 5-isopropenylpyrazole, 2-isopropenyl 1, Ethylenically unsaturated heterocyclic compounds such as 3,4-oxadiazole, vinyltetrazole, 2-vinylpyridine, 4-vinylpyridine, 2-isopropenylpyridine, 3-vinylpyridine, 3-isopropenylpyridine, 2-vinylquinoline, 2-isopropenylquinoline, 4-vinylquinoline, 4-vinylpyrimidine, 2,4-dimethyl-6-vinyl-S-triazine, 3-methylidenedihydrofuran-2(3H)-one, 4-methyl-3-methylidenedihydrofuran-2(3H)-one, and 4-decyl-3-methylidenedihydrofuran-2(3H)-one; and phosphate esters having an ethylenically unsaturated group such as dimethyl methacryloyloxymethyl phosphate and 2-methacryloyloxy-1-methylethyl phosphate.

[0037] In the polymer (A) of the present embodiment, the radical polymerizable monomer is preferably at least one selected from ethylene, an olefin having 3 to 12 carbon atoms, a (meth)acrylic acid alkyl ester, vinyl norbornene, vinyl acetate, vinyl ketone, vinyl chloride, vinylidene chloride, and vinylidene fluoride, more preferably at least one selected from the group consisting of ethylene and an olefin having 3 to 12 carbon atoms, even more preferably at least one selected from the group consisting of ethylene and an α-olefin having 3 to 6 carbon atoms, and still more preferably ethylene. These radical polymerizable monomers may be used alone or in combination of two or more.

[0038] Specific examples of formula (1-A) include repeating units having a branched structure in low-density polyethylene structures known as LDPE and linear low-density polyethylene structures known as LLDPE.

[0039] The total amount of structural units (preferably ethylene units) represented by formula (1-A) in polymer (A) of this embodiment is not particularly limited, but is preferably 80.0 mol% or more, more preferably 85.0 mol% or more, more preferably 90.0 mol% or more, even more preferably 91.0 mol% or more, even more preferably 91.5 mol% or more, and most preferably 92.0 mol% or more, relative to 100% of the total number of moles of polymer (A). On the other hand, the total amount of structural units (preferably ethylene units) represented by formula (1-A) in prepolymer (A) is not particularly limited, but is preferably 99.9 mol% or less, more preferably 99.5 mol% or less, even more preferably 99.2 mol% or less, even more preferably 99.1 mol% or less, and even more preferably 99.0 mol% or less, relative to 100% of the total number of moles of polymer (A). The upper and lower limits can be combined arbitrarily. For example, the content of the radical polymerizable monomer units (preferably ethylene units) in the polymer (A) of this embodiment is preferably 80.0 mol% or more and 99.9 mol% or less, more preferably 85.0 mol% or more and 99.9 mol% or less, still more preferably 90.0 mol% or more and 99.5 mol% or less, still more preferably 91.0 mol% or more and 99.2 mol% or less, still more preferably 91.5 mol% or more and 99.1 mol% or less, and most preferably 92.0 mol% or more and 99.0 mol% or less, relative to 100% of the total number of moles of the polymer (A) of this embodiment.

[0040] On the other hand, in the polymer of this embodiment, the constitutional unit represented by formula (1-B) is preferably derived from a cyclic ketene acetal. In particular, the polymer of this embodiment has a high proportion of cyclic ketene acetal. Increasing the proportion of cyclic ketene acetal tends to improve biodegradability and recyclability. The cyclic ketene acetal is more preferably represented by formula (3), more preferably represented by formula (4), and even more preferably represented by formula (5). [ka] (In formula (3), R 1 and R 2 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. 1 and R 2 may be bonded to each other to form a cyclic structure, and n represents an integer of 1 to 3. [ka] (In formula (4), R 1 and R 2 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. 1 and R 2 may be bonded to each other to form a cyclic structure. [ka]

[0041] Specific examples of the cyclic ketene acetal include 2-methylene-1,3-dioxane, 2-methylene-1,3-dioxepane, 2-methylene-1,3-dioxocane, 5-methyl-2-methylene-1,3-dioxane, 5-methyl-2-methylene-1,3-dioxepane, 6-methyl-2-methylene-1,3-dioxocane, 5,6-dimethyl-2-methylene-1,3-dioxepane, 5-tert-butyl-2-methylene-1,3-dioxane, 5-tert-butyl-2-methylene-1,3-dioxepane, 6-tert-butyl-2-methylene-1,3-dioxocane, 5-cyclohexyl-2-methylene-1,3-dioxane, 5-cyclohexyl-2-methylene-1, 3-dioxepane, 6-cyclohexyl-2-methylene-1,3-dioxocane, 2-methylene-5-phenyl-1,3-dioxane, 2-methylene-5-phenyl-1,3-dioxane, 2-methylene-6-phenyl-1,3-dioxocane, 5,5-dimethyl-2-methylene-1,3-dioxane, 5-ethyl-5-methyl-2-methylene-1,3-dioxane, 5-ethyl-2-methylene-1,3-dioxane, 5,5-dimethyl-2-methylene-1,3-dioxane, 5-ethyl-5-methyl-2-methylene-1,3-dioxane, 5,6-dimethyl-2-methylene-1,3-dioxocane, 2-methylene-5,6,7-trimethyl-1,3-dioxocane, and the like.

[0042] Among these, the cyclic ketene acetal is preferably 2-methylene-1,3-dioxepane, 5-methyl-2-methylene-1,3-dioxepane, 5,6-dimethyl-2-methylene-1,3-dioxepane, 5-tert-butyl-2-methylene-1,3-dioxepane, 5-cyclohexyl-2-methylene-1,3-dioxepane, 2-methylene-5-phenyl-1,3-dioxepane, 5,5-dimethyl-2-methylene-1,3-dioxepane, or 5-ethyl-5-methyl-2-methylene-1,3-dioxepane, and more preferably 2-methylene-1,3-dioxepane (n=2 in formula (2)). These cyclic ketene acetals may be used alone or in combination of two or more.

[0043] In the polymer (A) of this embodiment, the content of the structural unit represented by formula (1-B) is not particularly limited, and is preferably 0.1 mol% or more, more preferably 0.5 mol% or more, even more preferably 0.8 mol% or more, even more preferably 0.9 mol% or more, and even more preferably 1.0 mol% or more, relative to 100% of the total number of moles of the polymer (A). Depending on the intended use, it may be 2.0 mol% or more, 3.0 mol% or more, or 4.0 mol% or more. Meanwhile, the content of the structural unit represented by formula (1-B) is not particularly limited, and is preferably 20.0 mol% or less, more preferably 17.0 mol% or less, even more preferably 15.0 mol% or less, even more preferably 13.0 mol% or less, even more preferably 10.0 mol% or less, even more preferably 9.0 mol% or less, particularly more preferably 8.5 mol% or less, and most preferably 8.0 mol% or less, relative to 100% of the total number of moles of the polymer (A). The upper and lower limits can be combined arbitrarily. For example, the content of the structural unit represented by the formula (1-B) is not particularly limited, and is preferably 0.1 mol% or more and 20.0 mol% or less, more preferably 0.5 mol% or more and 18.0 mol% or less, even more preferably 0.8 mol% or more and 17.0 mol% or less, still more preferably 0.9 mol% or more and 16.0 mol% or less, and even more preferably 1.0 mol% or more and 15.0 mol% or less, relative to 100% of the total number of moles of the polymer (A).

[0044] In the polymer (A) of the present embodiment, the structural unit represented by formula (1-A) and the structural unit represented by formula (1-B) are preferably, independently, a structural unit represented by formula (1-A-2) and a structural unit represented by formula (1-B-2). [ka] (In formula (1-A-1) and formula (1-B-2), l and m represent integers satisfying the condition 0.01≦l / (l+m)≦0.20. R 3 ~R 6each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. 3 ~R 6 At least one of them is a hydrocarbon group having 2 to 20 carbon atoms which may have a substituent.)

[0045] In formula (1-A-1) and formula (1-B-2), l, m, and l / (l+m) have the same meanings as l, m, and l / (l+m) in formula (1-A) and formula (1-B), and the preferred ranges are also the same. In formula (1-A-1), R 3 ~R 6 are each independently R in formula (2). 3 ~R 6 The same applies to the preferred range.

[0046] In the polymer (A) of this embodiment, the structural unit represented by formula (1-A) and the structural unit represented by formula (1-B) are usually randomly polymerized. In particular, it is preferable that the structural unit represented by formula (1-B) is bonded to the structural unit represented by formula (1-A) randomly and not consecutively. That is, the polymer (A) of this embodiment is -(1-A) m1 -(1-B)-(1-A) m2 It is preferable that the compound has a structure represented by the formula -, where Σmx, which is the sum of m1 and m2, corresponds to m in formula (1-A).

[0047] In the polymer (A) of the present embodiment, the content of the structural units represented by formula (1-A) and the structural units represented by formula (1-B) (preferably the content of the structural units represented by formula (1-A-2) and the structural units represented by formula (1-B-2)) is preferably 50 mol % or more, more preferably 70 mol % or more, even more preferably 90 mol % or more, even more preferably 95 mol % or more, even more preferably 99 mol % or more, and may be 100 mol % of all structural units excluding terminal groups.

[0048] The weight average molecular weight (Mw) of the polymer (A) of this embodiment is preferably 20,000 to 1,000,000. From the viewpoint of the mechanical strength and heat resistance of the resulting polymer, the lower limit of the weight average molecular weight (Mw) of the polymer (A) of this embodiment is preferably 30,000 or more, more preferably 40,000 or more, even more preferably 50,000 or more, and still more preferably 60,000 or more. On the other hand, the upper limit of the weight average molecular weight (Mw) of the polymer (A) of this embodiment is preferably 800,000 or less, more preferably 600,000 or less, even more preferably 400,000 or less, even more preferably 300,000 or less, and still more preferably 200,000 or less. The above upper and lower limits can be combined in any combination. For example, the weight average molecular weight (Mw) of the polymer (A) of this embodiment is preferably 30,000 or more and 800,000 or less, more preferably 40,000 or more and 600,000 or less, even more preferably 50,000 or more and 600,000 or less, and still more preferably 60,000 or more and 400,000 or less.

[0049] Furthermore, if the molecular weight distribution (weight average molecular weight / number average molecular weight: Mw / Mn) of the polymer (A) of the present embodiment is too small, the moldability of the polymer (A) may be reduced, whereas if it is too large, the mechanical properties and heat resistance of the polymer (A) may be reduced. Therefore, Mw / Mn is preferably 1.7 to 20, more preferably 1.8 to 15, and even more preferably 1.9 to 10.

[0050] The Mw and Mw / Mn of the polymer (A) are values ​​measured by gel permeation chromatography (GPC), and the measurement conditions are as described in the examples below.

[0051] The Mw and Mw / Mn of the polymer (A) of the present embodiment can be controlled arbitrarily by appropriately optimizing known conditions such as the polymerization method and polymerization conditions for the polymer (A), the types and blending ratios of the raw materials for the polymer (A), and the type and amount of the polymerization catalyst.

[0052] The lower limit of the crystallization temperature of the polymer (A) of the present embodiment is not particularly limited and is preferably 65° C. or higher, more preferably 70° C. or higher, even more preferably 75° C. or higher, and particularly preferably 80° C. or higher. The upper limit of the crystallization temperature is not particularly limited and is preferably 120° C. or lower, more preferably 117° C. or lower, even more preferably 113° C. or lower, and particularly preferably 110° C. or lower, from the viewpoint that if the crystallization temperature is too high, the moldability of the obtained polymer (A) becomes difficult. The above upper and lower limits can be combined in any manner. For example, the suitable range of the crystallization temperature of the polymer (A) of this embodiment is preferably 65 to 120°C, more preferably 70 to 117°C, still more preferably 75 to 113°C, and particularly preferably 80 to 110°C. The method for measuring the crystallization temperature in this embodiment will be described in detail later.

[0053] The lower limit of the melting point of the polymer (A) of this embodiment is not particularly limited, and from the viewpoint of improving the heat resistance and mechanical strength of the polymer (A), it is preferably 80° C. or higher, more preferably 85° C. or higher, even more preferably 90° C. or higher, and particularly preferably 95° C. or higher. The upper limit of the melting point is not particularly limited, and from the viewpoint that if the melting point is too high, the resulting polymer (A) becomes brittle and prone to cracking, it is preferably 135° C. or lower, more preferably 130° C. or lower, even more preferably 125° C. or lower, and particularly preferably 120° C. or lower. The above upper and lower limits can be combined in any manner. For example, the melting point of the polymer (A) in the present invention is preferably in the range of 80 to 135°C, more preferably 85 to 130°C, still more preferably 90 to 125°C, and particularly preferably 95 to 120°C. The method for measuring the melting point in the present invention will be described in detail later.

[0054] The polymer (A) of this embodiment can be used for various industrial materials. In this embodiment, the polymer (A) of this embodiment can be used as a composition containing the polymer (A). The polymer (A) of this embodiment contained in the composition may be one type or two or more types. The composition may contain other resins, known fillers, known additives, etc., as necessary, within the scope of not impairing the effects of the present invention.

[0055] [Polymer manufacturing method] The method for producing polymer (A) of the present embodiment is a method for producing a polymer containing a structural unit represented by formula (1-A) and a structural unit represented by formula (1-B), and includes heating and polymerizing at least a radically polymerizable monomer and a cyclic ketene acetal in the presence of a radical polymerization initiator under a pressure of 1 MPa to 20 MPa. [ka] (In formula (1-A) and formula (1-B), l and m represent integers satisfying 0.01≦l / (l+m)≦0.20, and n represents an integer of 1 to 3. 1 and R 2 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. 1 and R 2 may be bonded to each other to form a cyclic structure. Z includes a structure represented by formula (2). stomach.) [ka] (In formula (2), R 3 ~R 6 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. 3 ~R 6 At least one of them is a hydrocarbon group having 2 to 20 carbon atoms which may have a substituent.)

[0056] In this embodiment, it is presumed that a polymer having a branched structure was successfully obtained by polymerizing the raw material radical polymerizable monomers and the like by heating them under a pressure of 1 MPa to 20 MPa. The preferred range of the polymer (A) containing the structural unit represented by formula (1-A) and the structural unit represented by formula (1-B) is the same as that described above in the section [Polymer], and the preferred range is also the same. The preferred range of the radical polymerizable monomer is the same as that described in the above section [Polymer], and the preferred range is also the same. The preferred range of the cyclic ketene acetal is the same as that described in the above section [Polymer], and the preferred range is also the same.

[0057] The radical polymerization initiator is not particularly limited as long as it generates reactive radicals. As the polymerization initiator, known radical initiators can be used alone or in combination.

[0058] Specific examples of the radical initiator include known peroxide initiators such as di-t-butyl peroxide, t-hexylperoxyisopropyl monocarbonate, t-hexylperoxy 2-ethylhexanoate, t-butyl peroxypivalate, t-hexyl peroxypivalate, benzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, and lauroyl peroxide, as well as azo initiators such as 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylpropionitrile), 2,2'-azobis(2-methylbutyronitrile), and dimethyl 2,2'-azobis(2-methylpropionate). Among these, di-t-butyl peroxide, t-hexylperoxy 2-ethylhexanoate, 1,1-bis(t-hexylperoxy)cyclohexane, dimethyl 2,2'-azobis(2-methylpropionate), and 2,2'-azobis(isobutyronitrile) are preferred. These polymerization initiators can be used alone or in combination of two or more.

[0059] The amount of the polymerization initiator used is not particularly limited, and is usually preferably 0.01 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, and even more preferably 0.5 to 10 parts by mass, relative to 100 parts by mass of the cyclic ketene acetal used in the polymerization reaction.

[0060] Examples of chain transfer agents used in the radical polymerization method for producing the polymer (A) include alkyl mercaptans such as n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, 1,4-butanedithiol, 1,6-hexanedithiol, ethylene glycol bisthiopropionate, butanediol bisthioglycolate, butanediol bisthiopropionate, hexanediol bisthioglycolate, hexanediol bisthiopropionate, trimethylolpropane tris-(β-thiopropionate), and pentaerythritol tetrakisthiopropionate. Among these, monofunctional alkyl mercaptans such as n-octyl mercaptan and n-dodecyl mercaptan are preferred. These chain transfer agents can be used alone or in combination of two or more.

[0061] The amount of the chain transfer agent used is not particularly limited, but is typically 0.1 to 1 part by mass, preferably 0.15 to 0.8 parts by mass, more preferably 0.2 to 0.6 parts by mass, and even more preferably 0.2 to 0.5 parts by mass, per 100 parts by mass of the monomers (total amount of radically polymerizable monomers and monomers such as cyclic ketene acetal) used in the polymerization reaction. The amount of the chain transfer agent used is typically 2,500 to 10,000 parts by mass, preferably 3,000 to 9,000 parts by mass, and more preferably 3,500 to 6,000 parts by mass, per 100 parts by mass of the polymerization initiator. Alternatively, a reaction solvent or the like may also function as the chain transfer agent, without using a chain transfer agent.

[0062] In this embodiment, the pressure during polymerization is 1 MPa to 20 MPa, preferably 18 MPa or less, more preferably 16 MPa or less, even more preferably 10 MPa or less, even more preferably 7 MPa or less, more preferably 2 MPa or more, and even more preferably 2.5 MPa or more. By setting the pressure at or below the upper limit, the effect of (reducing the reactor for polymer production and its maintenance costs) tends to be further improved. On the other hand, by setting the pressure at or above the lower limit, (polymerization activity and molecular weight of the polymer) tends to be further improved. Also, The pressure during the polymerization can be arbitrarily combined, and is preferably 2 to 18 MPa, more preferably 2 to 16 MPa, even more preferably 2 to 10 MPa, still more preferably 2 to 7 MPa, and even more preferably 2.5 to 7 MPa.

[0063] In the method for producing a polymer of this embodiment, the heating temperature during polymerization is preferably 60 to 85°C. The heating temperature is preferably 65° C. or higher, and preferably 83° C. or lower, and more preferably 80° C. or lower. By setting the temperature at or above the lower limit, productivity tends to improve due to an increase in polymerization rate and a decrease in viscosity of the polymerization liquid. On the other hand, by setting the temperature at or below the upper limit, control of the polymerization rate becomes easier, and further, the production of by-products is suppressed, thereby suppressing coloration of the polymer (A). The heating temperatures can be arbitrarily combined, and are preferably 65 to 83°C, and more preferably 65 to 80°C.

[0064] In the radical polymerization method for producing the polymer (A) of this embodiment, the polymerization reaction time is not particularly limited and is usually 0.5 to 10 hours, preferably 1.0 to 9 hours, and more preferably 1.0 to 8 hours.

[0065] The radical polymerization may be carried out in the absence of a solvent or in a solvent, and is preferably carried out in a solvent from the viewpoint of producing a polymer (A) with a low viscosity. In order to prevent the polymer (A) from being discolored, the polymerization reaction is preferably carried out in a low dissolved oxygen atmosphere and in an inert gas atmosphere such as nitrogen gas.

[0066] The solvent used in the radical polymerization method for producing the polymer (A) of the present embodiment is not particularly limited as long as it can dissolve the raw material monomers and the polymer (A) and does not inhibit the radical polymerization. For example, a solvent with low radical scavenging properties, such as a tertiary alcohol such as t-butanol or 2-methyl-2-butanol, or dimethyl carbonate (DMC), can be used. These solvents can be used alone or in combination of two or more. The amount of the solvent used can be appropriately set in consideration of the viscosity of the reaction solution and productivity. The amount of the solvent used is not particularly limited, and is usually 300 to 50,000 parts by mass, and preferably 600 to 20,000 parts by mass, per 100 parts by mass of the cyclic ketene acetal monomer used in the polymerization reaction.

[0067] In the method for producing polymer (A) of the present embodiment, when polymer (A) has a low molecular weight, the polymer (A) may be further increased in molecular weight. In this specification, the polymer (A) increased in molecular weight may be referred to as polymer (B) for convenience.

[0068] For example, the polymer obtained by heating at 60 to 85° C. can be further heated at 170 to 250° C. under reduced pressure in the presence of a metal catalyst to further increase the molecular weight. Furthermore, for example, the polymer obtained by heating at 60 to 85°C can be hydrolyzed and then heated under reduced pressure in the presence of a metal catalyst at 170 to 250°C to further increase the molecular weight. The hydrolysis is preferably carried out by heating at 130 to 200°C in an alcohol solvent in the presence of a basic catalyst. These steps will be described in detail below.

[0069] (Polycondensation step (X) for increasing molecular weight) The polycondensation step (X) for increasing the molecular weight is a step for obtaining a polymer (B) by increasing the molecular weight of the polymer (A). Examples of embodiments of the polycondensation step (X) include a method in which the polymer (A) is directly polycondensed using a known polycondensation method to obtain a polymer (B) with a higher molecular weight, and a method in which the polymer (A) is first decomposed into monomers and / or oligomers derived from the polymer (A) using a known polymer decomposition method such as hydrolysis, and then the obtained monomers and / or oligomers are polycondensed using a known polycondensation method or a known ring-opening polymerization method to obtain the polymer (B). The polycondensation step (X) may be either batch polymerization or continuous polymerization, and either a transesterification reaction or a direct polymerization reaction may be applied.

[0070] Examples of the metal catalyst (transesterification catalyst) used in the transesterification reaction include alkoxides and acetates of at least one metal selected from Mg, Mn, Zn, Ca, Li, Sn, and Ti, and dialkyl oxides of Sn. Examples of the polycondensation catalyst include compounds such as alkoxides and acetates of at least one metal selected from Sb, Ti, Ge, Sn, and Al, organic sulfonic acid compounds, and dialkyl oxides of Sn. If a product containing the polymer (B) obtained by the polymerization may come into direct contact with food, the product preferably does not contain Sb compounds or organic sulfonic acid compounds, and therefore, it is preferable to carry out polycondensation using a Ti or Ge compound as a polycondensation catalyst. Since the polymer (B) after polycondensation contains monomers, oligomers, and various by-products, it is preferable to carry out solid-state polymerization at a temperature of 170°C or higher under reduced pressure or in an inert gas flow.

[0071] One embodiment of the polycondensation step (X) includes a method in which the polymer (A) or a hydrolysis product of the polymer (A) is subjected to a polycondensation reaction in the presence of a catalyst at a temperature in the range of 170 to 250°C to obtain a polymer (B) having a higher molecular weight Mwb.

[0072] In the polycondensation step (X), it is preferable that the weight average molecular weight Mwa of the polymer (A) and the weight average molecular weight Mwb of the polymer (B) satisfy the relationship Mwa < Mwb from the viewpoint that the mechanical strength and heat resistance of the obtained polymer (B) are better. From the viewpoint that the mechanical strength and heat resistance of the obtained polymer (B) are better, the weight average molecular weight Mwb of the polymer (B) is preferably 3 times or more, more preferably 4 times or more, relative to the weight average molecular weight Mwa of the polymer (A), and is preferably 50 times or less, more preferably 40 times or less. More specifically, it is preferably 3 times or more and 50 times or less, and more preferably 4 times or more and 40 times or less.

[0073] The method for controlling the weight average molecular weight Mwa and the weight average molecular weight Mwb so as to satisfy the relationship Mwa < Mwb is not particularly limited. For example, the types and content ratios of the structural units represented by formula (1-A) and the constitutional units represented by formula (1-B) in the polymer (A) can be controlled by appropriately selecting and adjusting them by those skilled in the art. Also, the method for controlling so as to satisfy the relationship Mwa < Mwb includes the conditions of the polycondensation reaction in the polycondensation step (X), and the hydrolysis reaction of the hydrolysis step (X-1) and the polycondensation reaction of the polycondensation step (X-2), which may be included in the polycondensation step (X), and the conditions of the hydrolysis step (X-1-1) described below, which is included in the hydrolysis step (X-1), and further the conditions of the purification step (X-1-2) described below, which is provided as necessary. It may be a method of controlling by appropriately selecting and adjusting them by those skilled in the art.

[0074] In this embodiment, it is particularly preferable to carry out the polycondensation step (X) (particularly the polycondensation step (X-2) after hydrolysis) under high vacuum. By carrying out the polycondensation step (X) under high vacuum, the polymer (A) can be made to have a high molecular weight without using equipment that applies high pressure. In the past, high pressure was applied to increase the molecular weight of a polymer. However, the application of high pressure also poses problems with production equipment, etc. Under these circumstances, in the present invention, the polymerization condensation reaction is deliberately carried out under high vacuum, thereby successfully increasing the molecular weight of the polymer. The pressure in the polycondensation step (X) (particularly the polycondensation step (X-2) after hydrolysis) is preferably 1 mmHg or less, more preferably 0.8 mmHg or less, and even more preferably 0.5 mmHg or less. The pressure in the polycondensation step (X) refers to the final pressure. There is no particular lower limit for the pressure in the polycondensation step (X), but a pressure of 0.1 mmHg or more is practical. Therefore, the pressure in the polycondensation step (X) (particularly the polycondensation step (X-2) after hydrolysis) is preferably 0.1 mm or more and 1 mmHg or less, more preferably 0.1 mm or more and 0.8 mmHg or less, and even more preferably 0.1 mm or more and 0.5 mmHg or less.

[0075] An example of the polycondensation step (X) of this embodiment will be shown below. It goes without saying that the polycondensation step (X) of the present invention is not limited to the one described below. The following scheme (1) shows an embodiment in which the polycondensation step (X) includes a hydrolysis step (X-1) of hydrolyzing a polymer (A) to obtain a hydrolysis product derived from the polymer (A), and a polycondensation step (X-2) of polycondensing the obtained hydrolysis product to obtain the polymer (B). By hydrolyzing the polymer (A), a hydrolyzate of the polymer (A) is obtained. The hydrolyzate of the polymer (A) in Scheme (1) is obtained by decomposing some of the ester bonds of the polymer (A), and it is presumed that the resulting products include oligomer molecules having an OH group at one end and a COOH group at the other, decomposition products having an OH group at one end and not a COOH group at the other, and decomposition products having a COOH group at one end and not an OH group at the other. Of these, the low molecular weight components are easily soluble in water, and are therefore presumed to be removed before proceeding to the subsequent polycondensation step (X-2). In scheme (1), the polycondensation step (X-2) is carried out in the presence of the hydrolyzate. It is presumed that the polycondensation step (X-2) is carried out under high vacuum, and that the remaining decomposition products with one end group being an OH group and the other not a COOH group, and the decomposition products with one end group being a COOH group and the other not an OH group, are distilled off under reduced pressure. As a result, it is presumed that oligomer molecules with relatively high molecular weights, one end group being an OH group and the other being a COOH group, are preferentially left as raw materials for the polycondensation reaction (X-2). It is presumed that this resulted in a higher molecular weight for the resulting polymer (B). [ka]

[0076] In the above scheme (1), R x are each independently a hydrogen atom, -OH, or -COORy (Ry is a hydrogen atom or a methyl group). An example of the compound obtained in the above hydrolysis step (X-1) is presumed to be the following compound. [ka]

[0077] Furthermore, as shown in scheme (2), polymer (B) may be obtained from polymer (A) without going through a hydrolysis step. The following scheme (2) shows a scheme for obtaining polymer (B) by polycondensing polymer (A). In scheme (2), polymer (A) also contains a low molecular weight polymer component. Therefore, even if the polycondensation reaction of polymer (A) is carried out without a hydrolysis step, it is presumed that the low molecular weight polymer will be distilled off under reduced pressure by carrying out polycondensation step (X) under high vacuum. As a result, it is presumed that the molecular weight of the obtained polymer (B) can be increased. [ka]

[0078] The method for producing the polymer (B) of this embodiment will be described in more detail below. In the polycondensation step (X), the method for polycondensing the polymer (A) is not particularly limited. For example, a method may be mentioned in which the temperature is raised under normal pressure and an inert gas to carry out a first-stage initial polymerization of the polymer (A), and then the pressure is reduced to carry out a second-stage polymerization to obtain a high-molecular-weight polymer (B). Furthermore, after the first and second polymerization reactions, a polymer (B) having a higher molecular weight can be obtained by further carrying out solid-state polymerization or the like.

[0079] The conditions for the first-stage initial polymerization are not particularly limited, but it is desirable to increase the temperature from room temperature at a rate of 0.5 to 10°C / min, and once it reaches 170 to 250°C, keep the temperature constant and continue the reaction for an additional 30 minutes to 24 hours. The conditions for the second-stage polymerization, which is carried out under reduced pressure, are not particularly limited, but it is desirable to maintain the temperature increased in the initial polymerization and carry out the polymerization under pressure conditions of 10 mmHg or less, preferably 3 mmHg or less.

[0080] The timing of adding the transesterification catalyst and polycondensation catalyst is not particularly limited, and they may be added together with the polymer (A) or under reduced pressure after the completion of the initial polymerization. However, when the polymer (A) is a solution, it is desirable to add them after the completion of concentration under reduced pressure.

[0081] Furthermore, the polycondensation step (X) preferably includes a hydrolysis step (X-1) (described later) for hydrolyzing the polymer (A) to obtain a hydrolysis product derived from the polymer (A), and a polycondensation step (X-2) (described later) for polycondensing the obtained hydrolysis product to obtain the polymer (B). Unless otherwise specified, the various conditions in the polycondensation step (X-2) are the same for the polycondensation step (X) that does not undergo the hydrolysis step (X-1).

[0082] (Hydrolysis process (X-1)) The hydrolysis step (X-1) in the production method of this embodiment is a step for hydrolyzing the polymer (A) in the polycondensation step (X) to obtain a hydrolysis product derived from the polymer (A).

[0083] In the hydrolysis step (X-1), the structural unit (1) introduced into the main chain of the polymer (A) is hydrolyzed using a known hydrolysis method, whereby the polymer (A) can be decomposed into a hydrolysis product derived from the polymer (A) (for example, an oligomer represented by the formula (3) described below). The hydrolysis product obtained after hydrolysis here refers to an oligomer and / or monomer derived from the raw materials of the polymer (A). Specifically, it refers to an oligomer and / or monomer containing one or more units of the structural unit (1), cyclic ketene acetal unit, and radically polymerizable monomer unit contained in the polymer (A). In addition, a (co)polymer formed from the oligomer and / or monomer produced by hydrolysis is also referred to as a hydrolysis product.

[0084] Furthermore, from the viewpoint of obtaining a polymer (B) having a higher molecular weight, the hydrolysis step (X-1) preferably includes a hydrolysis step (X-1-1) in which the polymer (A) is hydrolyzed in an alcoholic solvent in the presence of a basic catalyst at a temperature in the range of 130°C to 200°C to obtain an oligomer and / or a monomer derived from the polymer (A).

[0085] The basic catalyst is not particularly limited, and may be any known basic catalyst used in a typical hydrolysis reaction, such as potassium hydroxide, sodium hydroxide, lithium hydroxide, etc. The basic catalyst may be used alone or in combination of two or more.

[0086] The alcohol solvent is not particularly limited, and may be a known alcohol such as methanol, ethanol, or isopropyl alcohol, particularly a lower alcohol having 1 to 3 carbon atoms. The alcohol solvent may be used alone or in combination of two or more.

[0087] The lower limit of the amount of the basic catalyst used in the hydrolysis step (X-1), particularly the hydrolysis step (X-1-1), is not particularly limited, and is usually preferably 0.8 equivalents or more, more preferably 1.0 equivalents or more, relative to the polymer (A). On the other hand, the upper limit of the amount of the basic catalyst used is not particularly limited, and is usually preferably 20 equivalents or less, more preferably 10 equivalents or less. If the amount of the basic catalyst used is above the lower limit, hydrolysis can be carried out at a sufficient hydrolysis rate. If the amount of the basic catalyst used is below the upper limit, post-treatment is easy and economical. The lower limit of the amount of the alcohol solvent used in the hydrolysis step (X-1), particularly the hydrolysis step (X-1-1), is not particularly limited, and is usually preferably 500 parts by mass or more, more preferably 600 parts by mass or more, per 100 parts by mass of the total mass of the polymer (A). On the other hand, the upper limit of the amount of the alcohol solvent used is not particularly limited, and is usually preferably 4000 parts by mass or less, more preferably 3000 parts by mass or less, per 100 parts by mass of the total mass of the polymer (A). If the amount of the alcohol solvent used is above the lower limit, hydrolysis will proceed sufficiently, and if it is below the upper limit, hydrolysis will be efficient.

[0088] The basic catalyst is usually used as an aqueous solution of about 1 to 6N. Therefore, water is present together with the alcohol-based solvent in the reaction system of the hydrolysis step (X-1), particularly the hydrolysis step (X-1-1). The upper limit of the amount of water present is not particularly limited, and is usually preferably 1,000 parts by mass or less, more preferably 700 parts by mass or less, per 100 parts by mass of the total mass of the polymer (A). On the other hand, the lower limit of the amount of water present is not particularly limited, and is usually preferably 100 parts by mass or more, more preferably 200 parts by mass or more, per 100 parts by mass of the total mass of the polymer (A). If the amount of water present is above the lower limit, hydrolysis proceeds sufficiently, and if it is below the upper limit, hydrolysis can be carried out efficiently.

[0089] The hydrolysis step (X-1), particularly the hydrolysis step (X-1-1), is preferably carried out under an inert gas atmosphere such as nitrogen, since it is carried out at high temperatures.

[0090] Furthermore, from the viewpoint of obtaining a polymer (B) with a higher molecular weight, it is preferable to polycondense the oligomer and / or monomer derived from the polymer (A) obtained in the hydrolysis step (X-1), particularly the hydrolysis step (X-1-1), in the polycondensation step (X-2) in the presence of a metal catalyst at a temperature in the range of 170°C or higher and 250°C or lower.

[0091] Furthermore, in order to obtain a polymer (B) having a higher molecular weight, the production method of this embodiment may, if necessary, include a purification step (X-1-2) after the hydrolysis step (X-1-1) and before the polycondensation step (X-2), in which the oligomer and / or monomer derived from the polymer (A) obtained in the hydrolysis step (X-1-1) is purified in the presence of a basic compound at a temperature in the range of 60°C or higher and 120°C or lower to obtain a purified product of the oligomer and / or monomer derived from the polymer (A). By carrying out the purification step (X-1-2), catalyst residue components and components that inhibit polycondensation contained in the oligomers and / or monomers derived from the polymer (A) obtained in the hydrolysis step (X-1-1) can be removed, and therefore, a polymer (B) with a higher molecular weight can be obtained in the subsequent polycondensation step (X-2).

[0092] The hydrolysis step (X-1), particularly the hydrolysis step (X-1-1) and the optional purification step (X-1-2) can be carried out in the presence of a solvent, while the polycondensation step (X-2) can be carried out using a solid-state polymerization method.

[0093] The purification temperature in the purification step (X-1-2) is preferably within the range of 60° C. or higher and 120° C. or lower, from the viewpoint of obtaining a polymer (B) with a higher molecular weight. The basic compound used in the purification step (X-1-2) is not particularly limited, and may be any known basic compound used in a typical hydrolysis reaction, such as potassium hydroxide, sodium hydroxide, lithium hydroxide, etc. These may be used alone or in combination of two or more. The solvent used in the purification step (X-1-2) is not particularly limited, and may be one or more of known solvents, such as methanol, ethanol, isopropyl alcohol, aromatic hydrocarbon compounds such as toluene and xylene, and polar solvents such as methyl isobutyl ketone.

[0094] The amounts of the basic compound and solvent used, the amount of water present, and the reaction atmosphere in the purification step (X-1-2) can be the same as those in the hydrolysis step (X-1-1).

[0095] The purification step (X-1-2) may be carried out in the same reaction vessel as the hydrolysis step (X-1-1) immediately after the hydrolysis step (X-1-1), or may be carried out by transferring the hydrolysis product after the hydrolysis step (X-1-1) to a separate reaction vessel.

[0096] Even when the hydrolysis step (X-1) is not performed, it is preferable to produce the polymer (A), purify it, and then carry out the polycondensation reaction.

[0097] The reaction time for the hydrolysis step (X-1) may be any time that allows oligomers and / or monomers of the desired molecular weight to be obtained from the polymer (A), and although it varies depending on the type of polymer (A), the reaction temperature, and other reaction conditions, it is usually about 1 to 20 hours. When the hydrolysis step (X-1) is carried out by the hydrolysis step (X-1-1) alone, the above reaction time is preferably the reaction time of the hydrolysis step (X-1-1) (about 1 to 20 hours). Furthermore, when the hydrolysis step (X-1) includes the hydrolysis step (X-1-1) and, if necessary, the purification step (X-1-2), it is preferable that the total reaction time of these steps is the above-mentioned reaction time (about 1 to 20 hours).

[0098] After completion of the hydrolysis step (X-1), the temperature is lowered, and then the pH is usually adjusted to 1 to 4 using an acid such as hydrochloric acid to facilitate post-treatment. The precipitated oligomer and / or monomer of polymer (A) is then subjected to solid-liquid separation, washed with a polar solvent such as acetone as necessary, and dried to recover the powdery oligomer and / or monomer of polymer (A). The molecular weight of the oligomer and / or monomer is not particularly limited, and the molecular weight can be controlled by appropriately adjusting the conditions for hydrolysis, etc., according to known techniques so that the mechanical strength of the finally obtained polymer (B) satisfies the desired performance. However, the hydrolysis product obtained in the hydrolysis step (X-1) can also be directly subjected to the subsequent polycondensation step (X-2) without separating and recovering the oligomer and / or monomer of the polymer (A).

[0099] (Polycondensation step (X-2)) The polycondensation step (X-2) in the production method of this embodiment is a step for polycondensing the oligomer and / or monomer of the polymer (A), which is the hydrolysis product obtained in the hydrolysis step (X-1), to obtain the polymer (B).

[0100] The embodiment of the polycondensation step (X-2) is not particularly limited, and examples thereof include known polycondensation methods and ring-opening polymerization methods. Either batch polymerization or continuous polymerization may be used, and either a transesterification reaction or a direct polymerization reaction may be applied.

[0101] One embodiment of the polycondensation step (X-2) includes a method in which the hydrolysis product of the polymer (A) obtained in the hydrolysis step (X-1) is subjected to a polycondensation reaction in the presence of a catalyst at a temperature in the range of 170 to 250°C to obtain a polymer (B) having a higher molecular weight.

[0102] Among the catalysts used in the polycondensation step (X-2), examples of the transesterification catalyst used in the transesterification reaction include alkoxides and acetates of at least one metal selected from Mg, Mn, Zn, Ca, Li, Sn, and Ti, and dialkyl oxides of Sn. Alkoxides of at least one metal selected from Mg, Mn, Zn, Ca, Li, and Ti are preferred, and alkoxides of Ti are more preferred.

[0103] Examples of the polycondensation catalyst include compounds such as alkoxides and acetates of at least one metal selected from Sb, Ti, Ge, Sn, and Al, organic sulfonic acid compounds, and dialkyl oxides of Sn. Alkoxides of at least one metal selected from Mg, Mn, Zn, Ca, Li, and Ti are preferred, and alkoxides of Ti are more preferred. When a product containing the polymer (B) obtained by the production method of the present embodiment may come into direct contact with food, the product preferably does not contain an Sb compound or an organic sulfonic acid compound, and therefore, it is preferable to carry out polycondensation using a Ti or Ge compound as a polycondensation catalyst.

[0104] The lower limit of the amount of polycondensation catalyst used in the polycondensation step (X-2) is not particularly limited, but is preferably 100 ppm by mass or more, more preferably 300 ppm by mass or more, per 100 parts by mass of the total mass of the oligomers and / or monomers of the polymer (A), which are usually hydrolysis products. On the other hand, the upper limit of the amount of polycondensation catalyst used is not particularly limited, but is preferably 5000 ppm by mass or less, more preferably 3000 ppm by mass or less, per 100 parts by mass of the total mass of the oligomers and / or monomers of the polymer (A), which are usually hydrolysis products. When the amount of polycondensation catalyst used is above the lower limit, the polycondensation reaction can be carried out at a sufficient reaction rate. When the amount of polycondensation catalyst used is below the upper limit, coloration is suppressed and economic efficiency is also excellent.

[0105] In addition, when the oligomer and / or monomer of the polymer (A) is obtained in a solid state as a hydrolysis product from the hydrolysis step (X-1), it is preferable to carry out the polycondensation reaction of the oligomer and / or monomer using a solid-state polymerization method. Alternatively, the polycondensation reaction can be carried out in a liquid phase by adding a solvent to the oligomer and / or monomer obtained in a solid state. When polycondensation reaction is carried out in a liquid phase, any solvent used in a general polycondensation reaction can be suitably used as the polycondensation reaction solvent, and specifically, known organic solvents such as diphenyl ether and toluene can be used. These solvents may be used alone or in combination of two or more. In addition, it is preferable to use a small amount of these solvents.

[0106] In the polycondensation step (X-2), the method for polycondensing the hydrolysis product is not particularly limited, and examples thereof include a method in which the temperature is raised under normal pressure and in an inert gas to carry out a first-stage initial polymerization of the hydrolysis product, and then the pressure is reduced to carry out a second-stage polymerization to obtain a high-molecular-weight polymer (B). Furthermore, after the first and second polymerization reactions, a polymer (B) having a higher molecular weight can be obtained by further carrying out solid-state polymerization or the like.

[0107] The conditions for the initial polymerization in the first stage are not particularly limited, but it is desirable to raise the temperature at a rate of 0.5 to 10 °C per minute from room temperature, keep the temperature constant when reaching 170 to 250 °C, and further react for 30 minutes to 24 hours. The conditions for the second-stage polymerization, which is further carried out under reduced pressure, are not particularly limited, but it is desirable to carry out the polymerization for 1 to 24 hours at a pressure condition of 10 mmHg or less, preferably 3 mmHg or less, while maintaining the temperature raised in the initial polymerization or at a temperature 5 to 20 °C higher than that. Since the polymer (B) after polymerization obtained by the polycondensation reaction contains monomers, oligomers, and various by-products, it is also a preferred embodiment to carry out solid-phase polymerization at a temperature of 170 °C or higher, specifically at a temperature of 170 to 230 °C, under reduced pressure or under the flow of an inert gas after the above-mentioned second-stage polymerization.

[0108] The addition time of the transesterification catalyst and the polycondensation catalyst is not particularly limited, and it may be charged together with the hydrolysis product, or may be added during the reduced-pressure state after the completion of the initial polymerization. However, when the hydrolysis product is in solution, it is desirable to add it after the concentration by reduced pressure is completed.

[0109] After the completion of the polycondensation reaction, the obtained polycondensation reaction product can be directly taken out, or an aromatic hydrocarbon solvent such as toluene or xylene can be added for reflux, and then the polycondensation reaction product after reflux can be added to a polar solvent such as acetone or methanol for precipitation, and the polymer (B) can be obtained by filtration and recovery.

[0110] In the polycondensation step (X-2), it is preferable that the weight-average molecular weight Mwa and the weight-average molecular weight Mwb satisfy the relationship of Mwa < Mwb from the viewpoint of better mechanical strength and heat resistance of the obtained polymer (B). The method for controlling so that the weight average molecular weight Mwa and the weight average molecular weight Mwb satisfy the relationship Mwa < Mwb is not particularly limited. For example, the structure of the structural unit (1) in the polymer (A), the content ratio of the structural unit (1), further, the structure and type of the cyclic ketene acetal unit contained in the structural unit (1) and the content ratio of the cyclic ketene acetal unit can be controlled by those skilled in the art appropriately selecting and adjusting. Alternatively, the method for controlling so as to satisfy the relationship Mwa < Mwb is a method in which those skilled in the art appropriately select and adjust the conditions of the hydrolysis reaction in the hydrolysis step (X-1) and the polycondensation reaction in the polycondensation step (X-2), and the treatment conditions of the hydrolysis step (X-1-1) and the purification step (X-1-2) provided as necessary, which are included in the hydrolysis step (X-1).

[0111] Regarding the matters described in the above (polycondensation step (X-2)), the polycondensation step (X) in the case where the hydrolysis step (X-1) is not obtained can be carried out in the same manner, and the same range is preferable.

[0112] In the present embodiment, a method for producing a polymer is also disclosed, which is a polymer containing a structural unit represented by the formula (1-A) and a constitutional unit represented by the formula (1-B), and includes heating and polycondensing an oligomer represented by the formula (3). Formula (3)

Chemical formula

Chemical formula

[0113] In formula (3), n represents an integer of 1 to 3. n in formula (3) has the same meaning as n in formula (1-B), and the preferred range is also the same. In formula (3), mp represents an integer of 4 to 99, preferably 5 or more, more preferably 7 or more, and preferably 66 or less, more preferably 49 or less. By making it equal to or greater than the lower limit, the polymer melting point tends to be high and heat resistance tends to be further improved. On the other hand, by making it equal to or less than the upper limit, hydrolysis reaction activity tends to be improved, and recyclability tends to be further improved. The upper and lower limits can be any combination, and are preferably 5 to 99, and more preferably 7 to 66.

[0114] In formula (3), R 1 and R 2 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. 1 and R 2 may be bonded to each other to form a cyclic structure. 1 and R 2 is R in formula (1-B) 1 and R 2 has the same meaning as above, and the preferred range is also the same.

[0115] In formula (3), Z includes a structure represented by formula (2). Z in formula (3) has the same meaning as Z in formula (1-A), and the preferred range is also the same.

[0116] The oligomer represented by formula (3) may be a low molecular weight product of the above-mentioned polymer (A). The oligomer represented by formula (3) is preferably obtained by hydrolyzing a polymer (A) containing a structural unit represented by formula (1-A) and a structural unit represented by formula (1-B). In particular, recycled products of the polymer (A) can also be hydrolyzed and used. When the polymer (A) is hydrolyzed, it is preferably carried out by heating in an alcoholic solvent in the presence of a basic catalyst at 130 to 200° C. The hydrolysis of the polymer (A) is preferably carried out in the same range as in the hydrolysis of the polymer (A) described above (hydrolysis step (X-1)).

[0117] In this embodiment, it is also preferable to further increase the molecular weight of the polymer obtained by heating at 130 to 200° C. by heating it at 170 to 250° C. under reduced pressure in the presence of a metal catalyst. The details and preferred ranges are the same as those for the increase in molecular weight of the polymer (A) (polycondensation step (X)) described above.

[0118] The polymer (A) of this embodiment can be hydrolyzed to obtain an oligomer represented by formula (3), and then the obtained oligomer represented by formula (3) can be polycondensed again to obtain polymer (A). Therefore, for example, recycled products of polymer (A) can be collected from the market and hydrolyzed to obtain the oligomer represented by formula (3).Furthermore, the obtained oligomer represented by formula (3) can be polycondensed to obtain polymer (A), which can be reused. The polymer (A) of this embodiment is thus a material that can be chemically recycled at low energy costs. In particular, when the structural unit represented by formula (1-A) is polyethylene, it can be preferably used as a substitute for polyethylene.

[0119] The polymer of this embodiment exhibits excellent coating properties, printability, antistatic properties, inorganic filler dispersibility, adhesion to other resins, and compatibilization with other resins due to the effects of the ester groups of the polymer. Utilizing these properties, the copolymer of the present invention can be used in a variety of applications. For example, it can be used as a film, a sheet, an adhesive resin, a binder, a compatibilizer, etc. [Example]

[0120] The present invention will be explained in more detail below by way of experimental examples in place of working examples, but the present invention is not limited to the following examples as long as it does not depart from the gist of the invention. The following examples are merely illustrative and are not intended to limit any of the embodiments described herein. The following examples do not limit the present invention in any way. The values ​​of various manufacturing conditions and evaluation results in the following experimental examples are meant as preferred upper or lower limit values ​​in the embodiments of the present invention, and a preferred range may be defined by a combination of the above-mentioned upper or lower limit value and the values ​​of the following examples or values ​​of the examples themselves.

[0121] [raw materials] The abbreviations for the raw materials used in the experimental examples are as follows: DMC: Dimethyl carbonate (product name: Dimethyl carbonate, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) 2-Methylene-1,3-dioxepane (CKA) (synthesized based on U.S. Patent Application Publication No. 2013 / 344159, U.S. Patent No. 5,455,361, and Journal of Organic Chemistry 1999, 64, 8386-8395) Co(salen) complex: a complex of cobalt and a salen ligand (trade name: (R,R)-(-)-N,N'-bis(3,5-di-t-butylsalicylidene)-1,2-cyclohexanediaminocobalt(II), manufactured by Sigma-Aldrich Japan) AIBN: Azoisobutylnitrile (trade name: 2,2'-azobis(isobutyronitrile), manufactured by Tokyo Chemical Industry Co., Ltd.) Ti(OiPr)4: tetraisopropyl orthotitanate (trade name: tetraisopropyl orthotitanate, manufactured by Tokyo Chemical Industry Co., Ltd.) tBuOH: tert-butyl alcohol (trade name: tert-butyl alcohol, manufactured by Tokyo Chemical Industry Co., Ltd.) Ti(OBu)4: Tetrabutyl orthotitanate (trade name: Titanium tetrabutoxide monomer, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[0122] In the following experimental examples, various physical properties were measured by the following methods.

[0123] [Evaluation method] <Melting point (Tm) and crystallization temperature (Tc)> The melting point (Tm) and crystallization temperature (Tc) of the polymers and hydrolysis products obtained in the experimental examples were measured using a differential scanning calorimeter (DSC) (manufactured by Hitachi High-Tech Science Corporation, model name: TA7000 DSC7020AS-3D) according to the following procedure. Approximately 1 mg of the polymer was placed in a sample container and held at 30°C for 3 minutes under a nitrogen gas atmosphere. The sample was then heated from 30°C to 210°C at a heating rate of 10°C / min and held at 210°C for 5 minutes. The sample was then cooled from 210°C to -10°C at a cooling rate of 10°C / min and held at -10°C for 5 minutes. The sample was then heated from -10°C to 210°C at a heating rate of 10°C / min, and the melting point (Tm) and crystallization temperature (Tc) (unit: °C) were determined.

[0124] <Weight average molecular weight (Mw), number average molecular weight (Mn), molecular weight distribution (Mw / Mn)> The weight average molecular weight (Mw) and number average molecular weight (Mn) of the polymer obtained in the experimental examples were determined by gel permeation chromatography (GPC measurement) according to the following procedure. A polymer sample (approximately 20 mg) was placed in a vial for a high-temperature GPC sample pretreatment device (manufactured by Polymer Laboratory, model PL-SP 260VS), and an o-dichlorobenzene solution containing BHT as a stabilizer (BHT concentration: 0.5 g / L) was added so that the polymer concentration became 0.1% by mass. Next, the vial containing the sample was placed in the high-temperature GPC sample pretreatment device and heated to 135°C to dissolve the polymer, followed by filtration using a glass filter to obtain a sample for GPC measurement. In either case, no polymer was observed trapped on the glass filter. Next, using a high-temperature GPC apparatus equipped with an RI detector (Tosoh Corporation, model name: HLC-8321GPC / HT, column: Tosoh Corporation TSKgel GMH-HT (30 cm × 4 columns)), GPC measurement was performed under the following measurement conditions: sample injection volume approximately 300 μL, column temperature 135°C, o-dichlorobenzene as the measurement solvent (mobile phase), and flow rate 1.0 mL / min. The molecular weight of the polymer was calculated based on a calibration curve relating retention time to molecular weight, which was created from the viscosity equation for ethylene polymers using commercially available monodisperse polystyrene as a standard sample. The viscosity equation is [η] = K × M α For polystyrene, K=1.38E -4 , α=0.70, and for ethylene polymers, K=4.77E -4 , α = 0.70 was used.

[0125] <Polymer composition analysis> 13 The composition of the polymer obtained in the experimental example was analyzed using a C-NMR measurement device (manufactured by Bruker, model name: AVANCE500MHz) according to the following procedure. 30 mg of the polymer was dissolved in 0.6 mL of ODCB (orthodichlorobenzene)-d4, and this was used as an NMR measurement sample. 13 Using a C-NMR measurement device, the measurement temperature was 130°C, pp: zgig (inverse gate decoupling 13C), the number of accumulations was 3000, and D1 was 14.8 seconds. 13 C-NMR measurements were performed. The assignments were based on Macromolecules 1984, 17, 1756-1761.

[0126] [Experimental Example 1] (Synthesis of Polymer (A-1)) As the polymer (A-1), an ethylene / 2-methylene-1,3-dioxepane (CKA) copolymer was synthesized by the following procedure. A mixture of CKA (30 mL, 29.1 g, 0.25 mol) and tBuOH (400 mL) was added to a 2 L pressure reactor (AC). Then, a solution (20 mL) of AIBN (0.66 g, 4.0 mmol) dissolved in CKA was introduced into the AC as a radical generator. The air in the AC was replaced with nitrogen gas (pressure 0.5 MPa) three times, and then the air in the AC was replaced with ethylene gas (pressure 0.2 MPa) three times. The temperature inside the AC was increased, and while supplying ethylene gas, the pressure inside the AC was maintained at 4.0 MPa and the temperature at 75°C, followed by stirring for 3 hours. Thereafter, the temperature inside the AC was cooled to room temperature (25°C), and the atmosphere inside the AC was replaced with nitrogen. The atmosphere inside the AC was replaced with nitrogen, and the polymerization solution was filtered from the bottom of the AC, washed with acetone (100 mL), and dried to obtain a white powder (19.82 g) of ethylene / CKA copolymer, which was designated as polymer (A-1). The resulting polymer (A-1) had a CKA-derived structural unit content of 7.5 mol % and an ethylene-derived structural unit content of 92.5 mol %, with the total structural units being 100 mol %. The polymer also had Mw = 12,700, Mn = 5,800, and Mw / Mn = 2.2. Two melting points (Tm) were observed: 89°C and 96°C. The crystallization temperature (Tc) was 85°C.

[0127] (Hydrolysis of Polymer (A-1)) A 2-L pressure reactor (AC) was charged with polymer (A-1) (23.23 g) and MeOH / 1N KOH (350 mL / 70 mL), and the atmosphere was replaced with nitrogen. The mixture was stirred for 5 hours at 160°C, and then the temperature inside the AC was cooled to room temperature (25°C). The resulting suspension was adjusted to pH 1-2 (acidic) using 1N HCl, and the resulting suspension was filtered, and the filtrate was added to distilled water (400 mL). Next, the distilled water containing the filtrate was stirred and then filtered, and the obtained filtrate was poured into acetone (400 mL). Next, the acetone containing the filtrate was stirred and then filtered, and the resulting filtrate was air-dried to obtain a white powder (15.9 g). The obtained powder was a hydrolysis product of polymer (A-1). Two melting points (Tm) of the hydrolysis product were observed, 94°C and 107°C. The crystallization temperatures (Tc) were 87°C and 97°C.

[0128] (Polycondensation of Hydrolysis Product of Polymer (A-1)) The hydrolysis product of polymer (A-1) (2.05 g) was placed in a glass reactor and purged with nitrogen. The mixture was heated to 140 °C and purged with nitrogen again. A toluene solution of Ti(OBu)4 (31 mmol / L, 0.1 mL, 0.003 mmol) was added, and the mixture was heated to 205 °C. The mixture was stirred at the same temperature for 1 hour and then reduced in pressure using a vacuum pump. Toluene (30 mL) was added and refluxed, and the resulting solution was poured into acetone (200 mL). To the residue, toluene (20 mL) was added again, refluxed, and poured back into acetone. The suspension was filtered, and the resulting precipitate was air-dried and placed in a tray to obtain a white powder (1.80 g) as polymer B, designated polymer (B-1).

[0129] The resulting polymer (B-1) had Mw = 121,000, Mn = 8,700, and Mw / Mn = 13.9. The CKA content of polymer (B-1) was 4.0 mol%, and the content of ethylene-derived structural units was 96.0 mol%. The melting point (Tm) was 99°C, and two crystallization temperatures (Tc) were observed, 88°C and 56°C. The branch number of the obtained polymer (B-1) was measured and is shown in Table 1.

[0130] [Experimental Example 2] (Synthesis of Polymer (A-2)) As the polymer (A-2), an ethylene / 2-methylene-1,3-dioxepane (CKA) copolymer was synthesized by the following procedure. Polymerization was carried out in the same manner as in Experimental Example 4, except that CKA (66 mL) and tBuOH (800 mL) were used, to obtain a copolymer (16.7 g), which was designated as polymer (A-2). The resulting polymer (A-2) contained 5.1 mol% of CKA-derived structural units and 94.9 mol% of ethylene-derived structural units, with the total structural units being 100 mol%. Mw = 12,000, Mn = 6,700, and Mw / Mn = 1.8. Two melting points (Tm) were observed: 101°C and 105°C. The crystallization temperatures (Tc) were 92°C and 57°C.

[0131] (Hydrolysis of Polymer (A-2)) A 2 L pressure reactor (AC) was charged with polymer (A-2) (45.77 g) and MeOH / 1N KOH (350 mL / 70 mL), and the atmosphere was replaced with nitrogen. The mixture was stirred for 5 hours at 160°C, and then the temperature inside the AC was cooled to room temperature (25°C). The resulting suspension was adjusted to pH 1-2 (acidic) using 1N HCl, and the suspension was filtered, and the resulting filtrate was poured into distilled water (400 mL). Next, the distilled water containing the filtrate was stirred and then filtered, and the filtrate obtained was poured into acetone (400 mL). Next, the acetone containing the filtrate was stirred and then filtered, and the resulting filtrate was air-dried to obtain a white powder (36.7 g). The obtained powder was a hydrolysis product of polymer (A-2). Two melting points (Tm) of the hydrolysis product were observed, 98°C and 110°C. The glass transition points (Tc) were 89°C and 99°C.

[0132] (Polycondensation of Hydrolysis Product of Polymer (A-2)) The hydrolysis product of polymer (A-2) (4.34 g) was placed in a glass reactor and purged with nitrogen. The mixture was heated to 140 °C and purged with nitrogen again. A toluene solution of Ti(OBu)4 (31 mmol / L, 0.2 mL, 0.006 mmol) was added, and the mixture was heated to 205 °C and stirred at the same temperature for 1.5 hours. The pressure was reduced using a vacuum pump. Toluene (20 mL) was added and refluxed. The resulting solution was poured into acetone (400 mL). To the residue, toluene (10 mL) was added, refluxed, and poured back into acetone. The suspension was filtered, and the precipitate was air-dried to obtain a white powder (4.16 g) of polymer B, designated polymer (B-2). The obtained polymer (B-2) had Mw = 91,300, Mn = 8,700, and Mw / Mn = 10.5. The CKA content of polymer (B-2) was 3.2 mol%, and the content of ethylene-derived structural units was 96.8 mol%. The melting point (Tm) was 101°C, and two crystallization temperatures (Tc) were observed, 91°C and 56°C. The branch number of the obtained polymer (B-2) was measured and is shown in Table 1.

[0133] [Experimental Example 3] (Synthesis of Polymer (A-3)) As the polymer (A-3), an ethylene / 2-methylene-1,3-dioxepane (CKA) copolymer was synthesized by the following procedure. Polymerization was carried out in the same manner as in Experimental Example 4, except that CKA (149 mL) and tBuOH (800 mL) were used and the polymerization time was changed to 5 hours, to obtain a copolymer (36.5 g), which was designated as polymer (A-3). The resulting polymer (A-3) contained 10.6 mol% of CKA-derived structural units and 89.4 mol% of ethylene-derived structural units, with the total structural units being 100 mol%. Its Mw was 12,100, Mn was 5,900, and Mw / Mn was 2.1. Two melting points (Tm) were observed: 81°C and 90°C. The crystallization temperatures (Tc) were 79°C and 46°C.

[0134] (Hydrolysis of Polymer (A-3)) A 2 L pressure reactor (AC) was charged with polymer (A-3) (34.33 g) and MeOH / 1N KOH (350 mL / 70 mL), and the atmosphere was replaced with nitrogen. The mixture was stirred for 5 hours at 160°C, and then the temperature inside the AC was cooled to room temperature (25°C). The resulting suspension was adjusted to pH 1-2 (acidic) using 1N HCl, and the suspension was filtered, and the resulting filtrate was poured into distilled water (400 mL). Next, the distilled water containing the filtrate was stirred and then filtered, and the obtained filtrate was poured into acetone (500 mL). Next, the acetone containing the filtrate was stirred and then filtered, and the resulting filtrate was air-dried to obtain a white powder (23.08 g). The obtained powder was a hydrolysis product of polymer (A-3). Two melting points (Tm) of the hydrolysis product were observed, 89°C and 102°C. The crystallization temperatures (Tc) were 83°C and 89°C.

[0135] (Polycondensation of Hydrolysis Product of Polymer (A-3)) The hydrolysis product (1.58 g) was placed in a glass reactor and purged with nitrogen. The mixture was heated to 140 °C and purged with nitrogen again. A toluene solution of Ti(OBu)4 (31 mmol / L, 0.10 mL, 0.003 mmol) was added, and the mixture was heated to 190 °C. The mixture was stirred at the same temperature for 30 minutes while flowing nitrogen. The mixture was stirred at the same temperature for 20 minutes, at 200 °C for 15 minutes, and at 205 °C for 1.5 hours while reducing the pressure to 130 °C. After cooling, toluene (20 mL) was added and refluxed. The solution was added to acetone (200 mL). To the residue, toluene (20 mL) was added, refluxed, and added again to acetone. The suspension was filtered, and the resulting white powder was placed in a tray and air-dried to obtain a white powder (1.48 g), designated Polymer (B-3). The resulting polymer (B-3) had Mw = 106,000, Mn = 7,900, and Mw / Mn = 13.5. The CKA content of polymer (B-3) was 6.9 mol%, and the content of ethylene-derived structural units was 93.1 mol%. The melting point (Tm) was 98°C, and two crystallization temperatures (Tc) were observed, 84°C and 55°C. The branch number of the obtained polymer (B-3) was measured and is shown in Table 1.

[0136] [Experimental Example 4] (Polycondensation of Polymer (A-1)) Polymer (A-1) (2.14 g) was placed in a glass reactor and purged with nitrogen. A toluene solution of Ti(OiPr)4 (30 mmol / L, 0.1 mL, 0.003 mmol) was added. The mixture was heated to 185 °C, and a toluene solution of Ti(OiPr)4 (30 mmol / L, 0.1 mL, 0.003 mmol) was added. The mixture was heated to 195 °C and stirred for 1.5 hours while reducing the pressure with a vacuum pump. The mixture was then stirred at 200 °C for 1.5 hours and at 205 °C for 3.5 hours. After cooling to 130 °C, toluene (15 mL) was added and refluxed. The resulting solution was poured into acetone (150 mL). The suspension was filtered, and the precipitate was air-dried to obtain a white powder (1.72 g), designated polymer (B-4). The resulting polymer (B-4) had Mw = 65,900, Mn = 4,400, and Mw / Mn = 15.0. The CKA content of polymer (B-4) was 5.9 mol%, and the content of ethylene-derived structural units was 94.1 mol%. The melting point (Tm) was 91°C, and two crystallization temperatures (Tc) were observed, 81°C and 48°C. The branch number of the obtained polymer (B-4) was measured and is shown in Table 1.

[0137] [Experimental Example 5] (Polycondensation of Polymer (A-2)) Polymer (A-2) (6.50 g) was placed in a glass reactor and purged with nitrogen. The mixture was heated to 150 °C, and a toluene solution of Ti(OBu)4 (30 mmol / L, 0.2 mL, 0.006 mmol) was added. The mixture was heated to 195 °C and stirred for 10 minutes while reducing the pressure with a vacuum pump, then at 205 °C for 5 hours (0.2 mL of the toluene solution of Ti(OBu)4 was added after 1 hour and 2 hours). The mixture was cooled to 130 °C, and toluene (30 mL) was added and refluxed. The resulting solution was poured into acetone (150 mL). The suspension was filtered, and the precipitate was air-dried to obtain a white powder (5.05 g), designated Polymer (B-5). The resulting polymer (B-5) had Mw = 41,600, Mn = 7,600, and Mw / Mn = 15.4. The CKA content of polymer (B-5) was 4.9 mol%, and the content of ethylene-derived structural units was 95.1 mol%. The melting point (Tm) was 98°C, and two crystallization temperatures (Tc) were observed, 89°C and 52°C. The branch number of the obtained polymer (B-5) was measured and is shown in Table 1.

[0138] [Experimental Example 6] (Synthesis of Polymer (A-6)) As the polymer (A-6), an ethylene / 2-methylene-1,3-dioxepane (CKA) copolymer was synthesized by the following procedure. Polymerization was carried out in the same manner as in Experimental Example 4, except that CKA (30 mL) and tBuOH (800 mL) were used and the polymerization time was 6 hours, to obtain a copolymer (5.9 g), which was designated as polymer (A-6). The resulting polymer (A-6) contained 2.6 mol% of CKA-derived structural units and 97.4 mol% of ethylene-derived structural units, with the total structural units being 100 mol%. Its Mw was 16,400, Mn was 8,800, and Mw / Mn was 1.9. Two melting points (Tm) were observed: 104°C and 108°C. The crystallization temperatures (Tc) were 95°C and 57°C.

[0139] (Polycondensation of polymer (A-6)) Polymer (A-6) (1.87 g) was placed in a glass reactor and purged with nitrogen. The mixture was heated to 160 °C, and 0.2 mL of a toluene solution of Ti(OBu)4 (30 mmol / L, 0.006 mmol) was added. The mixture was heated to 205 °C and stirred at the same temperature for 40 minutes while flowing nitrogen. The pressure was then reduced using a vacuum pump and the mixture was stirred for 2 hours. The mixture was then cooled to 130 °C, and toluene (30 mL) was added and refluxed. The resulting solution was poured into acetone (200 mL). The suspension was filtered, and the precipitate was air-dried to obtain a white powder (1.35 g), designated polymer (B-6). The resulting polymer (B-6) had Mw = 79,300, Mn = 9,900, and Mw / Mn = 8.0. The CKA content of polymer (B-6) was 2.3 mol%, and the content of ethylene-derived structural units was 97.7 mol%. The melting point (Tm) was 103°C, and two crystallization temperatures (Tc) were observed, 93°C and 54°C. The branch number of the obtained polymer (B-6) was measured and is shown in Table 1.

[0140] The number of branches for each experimental example is shown below.

[0141] [Table 1]

[0142] In Table 1 above, the number of branches indicates the number per 1,000 carbon atoms in the main chain. In Table 1 above, Me branch means a branched methyl group, Et branch means a branched ethyl group, and Bu branch means a branched butyl group. Long-chain branch means a branched group having 5 or more carbon atoms. Complex type means that the branched chains are complexed (they cannot be distinguished because peaks appear in the same region in NMR), and examples of such structures include the following: [ka] R is an alkyl group.

[0143] Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the invention.

Claims

1. A polymer comprising a structural unit represented by formula (1-A) and a structural unit represented by formula (1-B), and having a weight average molecular weight (Mw) of 20,000 to 1,000,000. 【Chemical 1】 (In formula (1-A) and formula (1-B), l and m represent integers satisfying 0.01≦l / (l+m)≦0.20, and n represents an integer of 1 to 3. １ and R ２ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. １ and R ２ may be bonded to each other to form a cyclic structure. Z includes a structure represented by formula (2). 【Chemistry 2】 (In formula (2), R ３ ~R ６ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. ３ ~R ６ At least one of the groups is a hydrocarbon group having 2 to 20 carbon atoms which may have a substituent.

2. In the formula (2), R ３ ~R ６ and at least one of the groups is a linear alkyl group having 2 to 20 carbon atoms which may have a substituent, a branched alkyl group having 3 to 20 carbon atoms which may have a substituent, or a cycloalkyl group having 3 to 20 carbon atoms which may have a substituent.

3. The polymer according to claim 1, wherein the constitutional unit represented by formula (1-A) is derived from a radical polymerizable monomer.

4. 4. The polymer according to claim 3, wherein the radical polymerizable monomer comprises at least one selected from the group consisting of ethylene and olefins having 3 to 12 carbon atoms.

5. The polymer according to claim 1, wherein the constitutional unit represented by formula (1-B) is derived from a cyclic ketene acetal.

6. The polymer according to claim 5 , wherein the cyclic ketene acetal is represented by formula (3): 【Chemistry 3】 (In formula (3), R １ and R ２ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. １ and R ２ may be bonded to each other to form a cyclic structure, and n represents an integer of 1 to 3.

7. The polymer according to claim 5 , wherein the cyclic ketene acetal is represented by formula (4): 【Chemistry 4】 (In formula (4), R １ and R ２ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. １ and R ２ may be bonded to each other to form a cyclic structure.)

8. The structural unit represented by formula (1-A) and the structural unit represented by formula (1-B) are, respectively and independently, a structural unit represented by formula (1-A-2) and a structural unit represented by formula (1-B-2). The polymer according to claim 1. 【Chemistry 5】 (In formula (1-A-1) and formula (1-B-2), l and m represent integers satisfying the condition 0.01≦l / (l+m)≦0.

20. R ３ ~R ６ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. ３ ~R ６ At least one of the groups is a hydrocarbon group having 2 to 20 carbon atoms which may have a substituent.

9. A method for producing a polymer containing a structural unit represented by formula (1-A) and a structural unit represented by formula (1-B), the method comprising: polymerizing at least a radically polymerizable monomer and a cyclic ketene acetal by heating under a pressure of 1 MPa to 20 MPa in the presence of a radical polymerization initiator. 【Chemistry 6】 (In formula (1-A) and formula (1-B), l and m represent integers satisfying 0.01≦l / (l+m)≦0.20, and n represents an integer of 1 to 3. １ and R ２ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. １ and R ２ may be bonded to each other to form a cyclic structure. Z includes a structure represented by formula (2). 【Chemistry 7】 (In formula (2), R ３ ~R ６ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. ３ ~R ６ At least one of the groups is a hydrocarbon group having 2 to 20 carbon atoms which may have a substituent.

10. The method for producing a polymer according to claim 9, wherein the radical polymerizable monomer comprises at least one selected from the group consisting of ethylene and olefins having 3 to 12 carbon atoms.

11. The method for producing a polymer according to claim 9 , wherein the cyclic ketene acetal is represented by formula (3): 【Chemistry 8】 (In formula (3), R １ and R ２ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. １ and R ２ may be bonded to each other to form a cyclic structure, and n represents an integer of 1 to 3.

12. The method for producing a polymer according to claim 9 , wherein the cyclic ketene acetal is represented by formula (4): 【Chemistry 9】 (In formula (4), R １ and R ２ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. １ and R ２ may be bonded to each other to form a cyclic structure.)

13. The method for producing a polymer according to claim 9, wherein the heating temperature during the polymerization is 60 to 85°C.

14. The method for producing a polymer according to claim 9, further comprising heating the polymer obtained by heating at 60 to 85°C at 170 to 250°C under reduced pressure in the presence of a metal catalyst to further increase the molecular weight.

15. The method for producing a polymer according to claim 9, comprising hydrolyzing the polymer obtained by heating at 60 to 85°C, and then heating it at 170 to 250°C under reduced pressure in the presence of a metal catalyst to further increase the molecular weight.

16. The method for producing a polymer according to claim 15, wherein the hydrolysis is carried out by heating in an alcoholic solvent at 130 to 200°C in the presence of a basic catalyst.

17. A method for producing a polymer comprising a structural unit represented by formula (1-A) and a structural unit represented by formula (1-B), the method comprising heating an oligomer represented by formula (3) to polycondense the polymer. 【Chemistry 10】 (In formula (3), n represents an integer of 1 to 3. mp represents an integer of 4 to 99. R １ and R ２ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. １ and R ２ may be bonded to each other to form a cyclic structure. Z includes a structure represented by formula (2). 【Chemistry 11】 (In formula (2), R ３ ~R ６ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. ３ ~R ６ At least one of the groups is a hydrocarbon group having 2 to 20 carbon atoms which may have a substituent. 【Chemistry 12】 (In formula (1-A) and formula (1-B), l and m represent integers satisfying 0.01≦l / (l+m)≦0.20, and n represents an integer of 1 to 3. １ and R ２ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. １ and R ２ may be bonded to each other to form a cyclic structure. Z includes a structure represented by formula (2). 【Chemistry 13】 (In formula (2), R ３ ~R ６ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. ３ ~R ６ At least one of the groups is a hydrocarbon group having 2 to 20 carbon atoms which may have a substituent.

18. The method for producing a polymer according to claim 17, comprising obtaining the oligomer represented by formula (3) by hydrolyzing a polymer (A) containing a structural unit represented by formula (1-A) and a structural unit represented by formula (1-B). 【Chemistry 14】 (In formula (1-A) and formula (1-B), l and m represent integers satisfying 0.01≦l / (l+m)≦0.20, and n represents an integer of 1 to 3. １ and R ２ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. １ and R ２ may be bonded to each other to form a cyclic structure. Z includes a structure represented by formula (2). 【Chemistry 15】 (In formula (2), R ３ ~R ６ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. ３ ~R ６ At least one of the groups is a hydrocarbon group having 2 to 20 carbon atoms which may have a substituent.

19. The method for producing a polymer according to claim 18, wherein the polymer (A) comprises a recycled product.

20. The method for producing a polymer according to claim 18, wherein the hydrolysis is carried out by heating in an alcoholic solvent at 130 to 200°C in the presence of a basic catalyst.

21. The method for producing a polymer according to claim 17, wherein the oligomer represented by formula (3) is heated to a temperature of 60 to 85°C.

22. The method for producing a polymer according to claim 21, further comprising heating the polymer obtained by heating at 60 to 85°C at 170 to 250°C under reduced pressure in the presence of a metal catalyst to further increase the molecular weight.

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