Polymer, flame-retardant composition, and method for producing polymer

Abstract

Provided are: a polymer containing a structural unit represented by general formula (I); a flame-retardant composition containing said polymer; and a method for producing said polymer. (In general formula (I), R1 represents a hydrogen atom or a methyl group. Each of R2 and R3 independently represents a group selected from the group consisting of a C1-6 alkyl group, a C1-6 alkyloxy group, a C2-6 alkenyl group, a C2-6 alkenyloxy group, a C7-12 aralkyl group, a C7-12 aralkyloxy group, a C6-12 aryl group, and a C6-12 aryloxy group. R2 and R3 may be bonded to each other, and n indicates an integer of 0-7.)

Description

[Technical Field]

[0001] The present invention relates to a polymer containing a specific phosphorus-containing structural unit, a flame-retardant composition containing the polymer, and a method for producing the polymer. [Background technology]

[0002] Resins containing methyl methacrylate (MMA) as their main component are highly transparent, weather-resistant, and have been used in a variety of applications. In recent years, these resins have been increasingly used in construction materials, taking advantage of their transparency and design, but these applications require high flame retardancy. Methods for imparting flame retardancy have been investigated, for example, as described in Patent Documents 1 and 2. Specifically, Patent Document 1 discloses a methacrylic resin composition obtained by polymerizing a polymerizable composition containing a monomer composition, a phosphate ester, and an antioxidant, and describes a halogenated phosphate ester as the phosphate ester. Patent Document 2 discloses a flame-retardant acrylic artificial marble obtained by curing a composition containing a resin component, an inorganic filler, a crosslinkable vinyl monomer, and an acrylic ester and / or a crosslinkable vinyl monomer, and describes aluminum hydroxide as the inorganic filler. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-74740 A [Patent Document 2] Japanese Patent Application Publication No. 10-25146 Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 uses a halogen-containing compound, but dehalogenation is desirable from the perspective of environmental impact, and there is also the problem of toxic gases being generated during combustion. Furthermore, when an inorganic flame retardant is added as in Patent Document 2, there is the problem of cloudiness occurring and loss of transparency. Furthermore, adding a large amount of flame retardant to improve flame retardancy reduces the performance of the cast plate itself, and furthermore, it softens during combustion, which poses the problem of inducing ignition to the surrounding area.

[0005] Therefore, an object of the present invention is to provide a polymer that is excellent in flame retardancy and is resistant to deterioration in physical properties such as softening when heated, a flame-retardant composition, and a method for producing the polymer. [Means for solving the problem]

[0006] As a result of intensive research to solve the above problems, the present inventors have found that when a polymer contains a specific phosphorus-containing structural unit, the polymer has excellent flame retardancy and is less likely to suffer from deterioration in physical properties such as softening when heated, and have completed the present invention.

[0007] That is, the present invention relates to the following [1] to

[12] . [1] A polymer containing a structural unit represented by the following general formula (I):

[0008] [ka] (In general formula (I), R 1 represents a hydrogen atom or a methyl group. 2 , R 3 R each independently represents any one selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, an alkyloxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkenyloxy group having 2 to 6 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, an aralkyloxy group having 7 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an aryloxy group having 6 to 12 carbon atoms. 2 , R 3 may be bonded to each other, and n is an integer of 0 to 7. [2] The polymer according to the above [1], wherein n in the general formula (I) is 5. [3] A flame-retardant composition comprising the polymer according to [1] or [2] above. [4] A flame-retardant sheet or board made using the polymer described in [1] or [2] above or the flame-retardant composition described in [3] above. [5] Compound (A) represented by the following general formula (II):

[0009] [ka] (In general formula (II), R 11 represents a hydrogen atom or a methyl group. 12 , R 13 R each independently represents any one selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, an alkyloxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkenyloxy group having 2 to 6 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, an aralkyloxy group having 7 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an aryloxy group having 6 to 12 carbon atoms. 12 , R 13 may be bonded to each other, and m is an integer of 0 to 7. [6] The compound (A) according to the above [5], wherein m in the general formula (II) is 5. [7] A method for producing a polymer, comprising a step of polymerizing a compound (B) represented by the following general formula (III) with a polymerizable monomer (C) in the presence of at least one phosphite ester compound (D) selected from the group consisting of phosphinite ester compounds, phosphonite monoester compounds, and phosphite diester compounds:

[0010] [ka] (In general formula (III), R 21 represents a hydrogen atom or a methyl group, and p is an integer of 0 to 7. [8] The method for producing a polymer according to the above [7], wherein the compound (B) is represented by the following general formula (IV):

[0011] [ka] (In general formula (IV), R 31 represents a hydrogen atom or a methyl group. [9] The method for producing a polymer according to the above [7] or [8], wherein the amount of the phosphite ester compound (D) added is 40 to 160 mol % relative to 100 mol % of the compound (B).

[10] A composition comprising a compound (B) represented by the following general formula (III), a polymerizable monomer (C), and at least one phosphite ester compound (D) selected from the group consisting of phosphinous acid ester compounds, phosphonous acid monoester compounds, and phosphite diester compounds:

[0012] [ka] (In general formula (III), R 21 represents a hydrogen atom or a methyl group, and p is an integer of 0 to 7.

[11] The composition according to the above

[10] , wherein the compound (B) is represented by the following general formula (IV):

[0013] [ka] (In general formula (IV), R 31 represents a hydrogen atom or a methyl group.

[12] The composition according to the above [9] or

[10] , wherein the content of the phosphite ester compound (D) is 40 to 160 mol % relative to 100 mol % of the compound (B). [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a polymer which has excellent flame retardancy and is resistant to deterioration in physical properties such as softening when heated, a flame-retardant composition, and a method for producing the polymer. DETAILED DESCRIPTION OF THE INVENTION

[0015] The following describes an example of an embodiment of the present invention (hereinafter, sometimes referred to as "the present embodiment"). However, the embodiment described below is merely an example for embodying the technical idea of ​​the present invention, and the present invention is not limited to the following description. In addition, although preferred embodiments are shown in this specification, a combination of two or more of the individual preferred embodiments is also a preferred embodiment. When there are several numerical ranges for matters shown as numerical ranges, the lower limit and upper limit can be selectively combined to form a preferred embodiment. In this specification, when a numerical range such as "XX to YY" is stated, it means "XX or more and YY or less." Furthermore, in this specification, "(meth)acrylate" means methacrylate and acrylate.

[0016] The polymer of this embodiment contains a specific phosphorus-containing structural unit, and therefore has excellent flame retardancy and can suppress deterioration of physical properties such as softening when heated. The flame-retardant composition containing the polymer has a low burning rate and produces almost no dripping. Furthermore, by using the polymer or the flame-retardant composition, it is possible to provide a flame-retardant sheet or a flame-retardant board having excellent flame retardancy. Furthermore, by employing a method for producing the polymer including specific steps, the polymer can be easily obtained. Furthermore, by employing the compound represented by the general formula (II), good flame retardancy can be exhibited.

[0017] <Polymer> The polymer of this embodiment contains a structural unit represented by the following general formula (I):

[0018] [ka]

[0019] The reason why the polymer of this embodiment has improved flame retardancy is not clear, but one possible reason is that it contains an abundance of phosphorus-carbon bonds, which results in a large amount of oxygen consumption during combustion, which is thought to be the reason for the improved flame retardancy.

[0020] In general formula (I), R 1 represents a hydrogen atom or a methyl group, and is preferably a methyl group from the viewpoint of polymerization operability.

[0021] In general formula (I), R 2 , R 3 R each independently represents any one selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, an alkyloxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkenyloxy group having 2 to 6 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, an aralkyloxy group having 7 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an aryloxy group having 6 to 12 carbon atoms. 2 , R 3 may be bonded to each other.

[0022] In general formula (I), R 2 , R 3 Examples of the alkyl group having 1 to 6 carbon atoms represented by include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a neopentyl group, an n-hexyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group.

[0023] In general formula (I), R 2 , R 3 Examples of the alkyloxy group having 1 to 6 carbon atoms represented by the formula (I) include a methoxy group, an ethoxy group, an n-propyloxy group, an isopropyloxy group, an n-butyloxy group, an isobutyloxy group, a sec-butyloxy group, a tert-butyloxy group, an n-pentyloxy group, an isopentyloxy group, a neopentyloxy group, an n-hexyloxy group, a cyclopropyloxy group, a cyclobutyloxy group, a cyclopentyloxy group, and a cyclohexyloxy group.

[0024] In general formula (I), R 2 , R 3 Examples of the alkenyl group having 2 to 6 carbon atoms represented by include a vinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, an isobutenyl group, a pentenyl group, a hexenyl group (such as a cis-3-hexenyl group), and a cyclohexenyl group.

[0025] In general formula (I), R 2 , R 3 Examples of the alkenyloxy group having 2 to 6 carbon atoms represented by the formula (I) include a vinyloxy group, an allyloxy group, a propenyloxy group, an isopropenyloxy group, a butenyloxy group, an isobutenyloxy group, a pentenyloxy group, a hexenyloxy group (such as a cis-3-hexenyloxy group), and a cyclohexenyloxy group.

[0026] In general formula (I), R 2 , R 3 Examples of the aralkyl group having 7 to 12 carbon atoms represented by include a benzyl group, a 2-phenylethyl group, and a 2-phenylpropyl group.

[0027] In general formula (I), R 2 , R 3 Examples of the aralkyloxy group having 7 to 12 carbon atoms represented by include a benzyloxy group, a 2-phenylethyloxy group, and a 2-phenylpropyloxy group.

[0028] In general formula (I), R 2 , R 3 Examples of the aryl group having 6 to 12 carbon atoms represented by include a phenyl group, a 2-methylphenyl group, a 2,4-dimethylphenyl group, and a 2-naphthyl group.

[0029] In general formula (I), R 2 , R 3 Examples of the aryloxy group having 6 to 12 carbon atoms represented by include a phenoxy group, a 2-methylphenoxy group, a 2,4-dimethylphenoxy group, and a 2-naphthoxy group.

[0030] Among these, from the viewpoint of improving flame retardancy, R 2 , R 3 is preferably an ethoxy group, an n-butyloxy group, a phenoxy group, or a phenyl group, and more preferably a phenoxy group or a phenyl group.

[0031] In general formula (I), R 2 , R 3 Examples of the structure of the phosphorus atom-containing moiety include the following structures:

[0032] [ka]

[0033] Among these, from the viewpoint of improving the flame retardancy of the resulting polymer and flame retardant composition, R 2 , R 3 The structure of the phosphorus atom-containing moiety including the following is preferred:

[0034] [ka]

[0035] In general formula (I), n is an integer of 0 to 7, and from the viewpoint of improving the physical properties of the resulting polymer and flame-retardant composition when heated, n is preferably 2 to 6, more preferably 3 to 6, and even more preferably 5.

[0036] In the polymer of this embodiment, the content of the structural unit represented by the general formula (I) is preferably 1 to 99% by mass, more preferably 5 to 80% by mass, even more preferably 10 to 70% by mass, and even more preferably 10 to 60% by mass. When the content of the structural unit represented by the general formula (I) is within the above range, it is possible to improve flame retardancy while further suppressing deterioration in physical properties such as softening upon heating.

[0037] (Polymerizable Monomer (C)) The polymer of this embodiment may contain structural units other than the structural units represented by general formula (I). For example, the polymer may exhibit decorative properties by containing a structural unit derived from the polymerizable monomer (C). Examples of the polymerizable monomer (C) include vinyl monomers, (meth)acrylic acid alkyl esters, (meth)acrylic acid esters, (meth)acrylates, and unsaturated dicarboxylic acids. Examples of the (meth)acrylic acid esters that can be used include those having a cyclic structure, a hydroxyl group, or an epoxy group at the terminal. Examples of the (meth)acrylates that can be used include those having an alkylene glycol structure, a silane group, or a silyl group at the terminal.

[0038] Examples of vinyl monomers include styrene, 2-methylstyrene, vinyl acetate, and vinyl chloride. Examples of the (meth)acrylic acid alkyl ester include methyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate.

[0039] Examples of the (meth)acrylic acid ester having a cyclic structure include cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, adamantyl (meth)acrylate, 3-hydroxyadamantyl (meth)acrylate, and 2-methyl-2-adamantyl (meth)acrylate.

[0040] Examples of the (meth)acrylic acid ester having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, and caprolactone-modified 2-hydroxyethyl (meth)acrylate.

[0041] Examples of the (meth)acrylic acid ester having an epoxy group at the terminal include glycidyl (meth)acrylate and 3,4-epoxycyclohexylmethyl (meth)acrylate.

[0042] Examples of (meth)acrylates having an alkylene glycol structure include methoxydiethylene glycol (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, isooctyloxydiethylene glycol (meth)acrylate, phenoxytriethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, and methoxypolyethylene glycol (meth)acrylate.

[0043] Examples of the silane or silyl group-terminated (meth)acrylate include 2-trimethylsiloxyethyl (meth)acrylate. Examples of the unsaturated dicarboxylic acid include maleic anhydride and its derivatives.

[0044] Furthermore, as the polymerizable monomer (C), a compound having two or more polymerizable groups in the molecule (excluding the compound (B) described later) may be used. Examples of the compound having two or more polymerizable groups in the molecule include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, and 1,9-nonanediol di(meth)acrylate. acrylate, 1,10-decanediol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, glycerin di(meth)acrylate, hydrogenated bisphenol A or hydrogenated bisphenol F di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylolpropane tri(meth)acrylate, and the like.

[0045] Alternatively, a hydroxyl group-containing polyvalent (meth)acrylic acid ester may be used as the polymerizable monomer (C). Examples of the hydroxyl group-containing polyvalent (meth)acrylic acid ester include glycerol di(meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol di(meth)acrylate, and dipentaerythritol monohydroxypenta(meth)acrylate.

[0046] Among these polymerizable monomers (C), from the viewpoints of processability and decorativeness, methyl (meth)acrylate and butyl (meth)acrylate are preferred, and methyl methacrylate is more preferred. These polymerizable monomers (C) may be used alone or in combination of two or more.

[0047] The content of the structural units derived from the polymerizable monomer (C) in the polymer of this embodiment is not particularly limited, but is preferably 1 to 99 mass%, more preferably 10 to 98 mass%, even more preferably 30 to 95 mass%, and even more preferably 40 to 90 mass%. When the content of the structural units derived from the polymerizable monomer (C) is within the above range, the processability and decoratability of the polymer can be improved while improving the flame retardancy.

[0048] These polymerizable monomers (C) can be polymerized to a certain extent before mixing with other components and used as a syrup for the purposes of ease of handling and shortening of polymerization time, etc. This procedure may be applied to all or only a portion of the polymerizable monomers (C).

[0049] <Polymer manufacturing method (1)> The polymer of this embodiment can be produced by applying a known polymerization method such as cationic polymerization, anionic polymerization, or radical polymerization to a polymerizable monomer that forms a structural unit represented by general formula (I). (Compound (A)) The polymerizable monomer forming the structural unit represented by general formula (I) may be a compound (A) represented by the following general formula (II): For example, a polymer production method (1) can be employed in which a raw material composition containing compound (A) and, as an optional component, the polymerizable monomer (C) is polymerized by the known polymerization method. By using compound (A), a polymer containing a structural unit represented by general formula (I) can be obtained, and furthermore, a large amount of phosphorus atoms can be contained in the molecular structure of the polymer. Therefore, dissolution or exudation (also called bleed-out) of the phosphorus-containing component due to heating does not occur, and good performance can be maintained.

[0050] [ka]

[0051] In general formula (II), R 11 , R12 , and R 13 are R in the above general formula (I), respectively. 1 , R 2 , and R 3 Therefore, a duplicated explanation will be omitted here.

[0052] R 11 , R 12 , and R 13 In the above general formula (I), R 1 , R 2 , and R 3 Therefore, a duplicated explanation will be omitted here.

[0053] In general formula (II), m is an integer of 0 to 7, and from the viewpoint of improving the physical properties of the resulting polymer and flame-retardant composition when heated, m is preferably 2 to 6, more preferably 3 to 6, and even more preferably 5. The compound (A) can be synthesized, for example, by utilizing and applying known chemical reactions.

[0054] In the polymer production method (1), the amount of compound (A) added is not particularly limited, but from the viewpoint of improving the flame retardancy of the flame-retardant composition described below, it is preferably 0.1 parts by mass or more, more preferably 1.0 parts by mass or more, and even more preferably 5.0 parts by mass or more, when the total amount of the raw materials is 100 parts by mass. Furthermore, from the viewpoint of moldability, the upper limit of the amount of compound (A) added is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and may be 20 parts by mass or less, when the total amount of the raw materials is 100 parts by mass.

[0055] <Polymer manufacturing method (2)> In addition to the above-described polymer production method (1), the polymer production method of this embodiment may also be a production method (2) comprising a step of polymerizing the compound (B) represented by general formula (III) and the polymerizable monomer (C) in the presence of at least one phosphite ester compound (D) selected from the group consisting of phosphinite ester compounds, phosphonite monoester compounds, and phosphite diester compounds. As described above, the polymer of this embodiment can be produced by applying a known polymerization method to a raw material composition containing compound (A). On the other hand, by employing the polymer production method (2), a polymer can be obtained without requiring multiple steps. Furthermore, a composition (raw material composition) containing compound (B) represented by general formula (III), polymerizable monomer (C), and at least one phosphite ester compound (D) selected from the group consisting of phosphite ester compounds, phosphonite monoester compounds, and phosphite diester compounds can be prepared, and then the raw material composition can be poured into a mold and polymerized and cured to obtain a molded article.

[0056] (Compound (B)) The compound (B) is represented by the following general formula (III).

[0057] [ka]

[0058] R 21 represents a hydrogen atom or a methyl group, and is preferably a methyl group from the viewpoint of polymerization operability.

[0059] p is any integer from 0 to 7, and is preferably 2 to 6, more preferably 3 to 6, and even more preferably 5, from the viewpoint of improving the physical properties of the resulting flame-retardant composition when heated. From the above viewpoint, the compound (B) is preferably a compound represented by the following general formula (IV).

[0060] [ka]

[0061] R 31 represents a hydrogen atom or a methyl group, and is preferably a methyl group from the viewpoint of polymerization operability.

[0062] In the polymer production method (2), the amount of compound (B) added is not particularly limited. On the other hand, from the viewpoint of imparting sufficient flame retardancy to the polymer and flame-retardant composition, the amount of compound (B) added is preferably 0.1 parts by mass or more, more preferably 3.0 parts by mass or more, and may be 10 parts by mass or more, when the total amount of raw materials is 100 parts by mass. The upper limit of the amount of compound (B) added is not particularly limited. On the other hand, from the viewpoint of molding processability, the amount of compound (B) added is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and may be 30 parts by mass or less, when the total amount of raw materials is 100 parts by mass. The preferred embodiment of the amount of compound (B) added can be interpreted as the preferred embodiment of the content of compound (B) relative to 100 parts by mass of the total amount of the raw material composition.

[0063] (Polymerizable Monomer (C)) In the method for producing a polymer (2), the polymerizable monomer (C) used is the same as the polymerizable monomer (C) described above, and therefore a duplicated description will be omitted here.

[0064] (Phosphite ester compound (D)) Examples of the phosphinous acid ester compound include diphenylphosphine oxide, diethylphosphine oxide, and dibutylphosphine oxide.

[0065] Examples of the phosphonous acid monoester compound include ethylphenylphosphinate, butylphenylphosphinate, phenylphenylphosphinate, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and the like.

[0066] Examples of phosphite diester compounds include diethyl phosphite, diisopropyl phosphite, dibutyl phosphite, 1,3-dioxa-2-phosphacyclohexane-2-oxide, 1,3-dioxa-5,5-dimethyl-2-phosphacyclohexane-2-oxide, diphenyl phosphite, bis(2,4-dimethyl)phenyl phosphite, and 1,2,3,4-tetrahydro-1,3-dioxa-2-phospha-naphthalene-2-oxide.

[0067] These phosphite ester compounds (D) may be used alone or in combination of two or more.

[0068] Among the above, from the viewpoints of raw material mixability and flame retardancy, the phosphite ester compound (D) is preferably diethyl phosphite, dibutyl phosphite, diphenyl phosphite, or 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and more preferably diethyl phosphite, dibutyl phosphite, or 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0069] The amount of the phosphite ester compound (D) added is not particularly limited. On the other hand, from the viewpoint of imparting sufficient flame retardancy to the polymer and flame-retardant composition, the amount of the phosphite ester compound (D) added is preferably 0.1 parts by mass or more, more preferably 3.0 parts by mass or more, and may also be 10 parts by mass or more, or 15 parts by mass or more, when the total amount of the raw materials is 100 parts by mass. In addition, there is no particular upper limit for the amount of the phosphite ester compound (D) added. On the other hand, from the viewpoint of molding processability, the amount of the phosphite ester compound (D) added is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, when the total amount of the raw materials is 100 parts by mass. The preferred amount of the phosphite ester compound (D) added can be interpreted as the preferred content of the phosphite ester compound (D) relative to 100 parts by mass of the total amount of the raw material composition.

[0070] The amount of the phosphite ester compound (D) added relative to 100 mol% of the compound (B) is not particularly limited. From the viewpoint of further improving flame retardancy, the amount of the phosphite ester compound (D) added relative to 100 mol% of the compound (B) is preferably 40 mol% or more, more preferably 50 mol% or more, even more preferably 60 mol% or more, and even more preferably 90 mol% or more. From the viewpoint of easily achieving both improved flame retardancy and avoiding elution and exudation of the phosphite ester compound (D), the amount of the phosphite ester compound (D) added relative to 100 mol% of the compound (B) is preferably 160 mol% or less, more preferably 150 mol% or less. The preferred embodiment of the amount of the phosphite ester compound (D) added relative to 100 mol% of the compound (B) can be interpreted as the preferred embodiment of the content of the phosphite ester compound (D) relative to 100 mol% of the compound (B) in the raw material composition.

[0071] (Radical polymerization initiator (E)) The polymer production method (2) may use a radical polymerization initiator (E). The type of radical polymerization initiator (E) is not particularly limited and can be appropriately selected depending on the types of compound (B), polymerizable monomer (C), and phosphite ester compound (D) used. Examples of the radical polymerization initiator (E) include a thermal radical polymerization initiator that generates radicals by heat and a photoradical polymerization initiator that generates radicals by light.

[0072] Examples of the thermal radical polymerization initiator include organic peroxides such as azo compounds such as 2,2'-azobisisobutyronitrile (AIBN) and 2,2'-azobis(2,4-dimethylvaleronitrile) (ADVN); diacyl peroxides such as benzoyl peroxide; peroxy esters such as t-butyl peroxybenzoate; hydroperoxides such as cumene hydroperoxide; dialkyl peroxides such as dicumyl peroxide; ketone peroxides such as methyl ethyl ketone peroxide and acetylacetone peroxide; peroxy ketals; alkyl peresters; and percarbonates.

[0073] As the photoradical polymerization initiator, commercially available products can be used. Examples include Irgacure (registered trademark, the same applies hereinafter) 651, Irgacure 184, Irgacure 2959, Irgacure 127, Irgacure 907, Irgacure 369, Irgacure 379, Irgacure 819, Irgacure 784, Irgacure OXE01, Irgacure OXE02, and Irgacure 754 (all manufactured by BASF). These may be used alone or in combination of two or more.

[0074] The amount of radical polymerization initiator (E) added is not particularly limited, but in order to obtain a polymer having a sufficient degree of polymerization, it is preferably 0.001 part by mass or more, and more preferably 0.001 part by mass or more and 3 parts by mass or less, when the total amount of the raw materials is 100 parts by mass.

[0075] The polymer production method (2) may be carried out using a mold. By polymerizing and curing using a mold, the shape of the mold can be imparted to the polymer, resulting in a cured polymer with excellent flame retardancy. Examples of the mold include a mold consisting of a pair of plates such as tempered glass, chrome-plated plate, or stainless steel plate and a gasket made of soft polyvinyl chloride resin, and a mold consisting of the opposing surfaces of a pair of endless belts running in the same direction at the same speed and gaskets running at the same speed as both endless belts on both side edges of the pair. Furthermore, by injecting a composition containing the raw material composition of the polymer as well as various additives that can be used in the flame-retardant composition described below into the mold, a cured product of the flame-retardant composition containing the polymer can be obtained in a state in which the shape of the mold is imparted.

[0076] The polymerization temperature is preferably two-stage, consisting of a primary curing at 40 to 90°C and a subsequent secondary curing at 110 to 140°C, in order to increase transparency and polymerization rate.

[0077] <Flame-retardant composition> The flame-retardant composition of this embodiment contains a polymer containing a structural unit represented by the above general formula (I). Because the polymer contains a phosphorus atom in its molecular structure, the phosphorus-containing component does not leach out or ooze out when heated, and the flame-retardant composition can maintain good flame retardancy.

[0078] The proportion of the polymer contained in the flame-retardant composition is not particularly limited, but from the viewpoint of flame retardancy, it is preferably 0.1 parts by mass or more, and more preferably 1.0 part by mass or more, relative to 100 parts by mass of the flame-retardant composition. The upper limit of the proportion of the polymer contained in the flame-retardant composition is not particularly limited, but from the viewpoint of moldability, it is preferably 50 parts by mass or less, and more preferably 30 parts by mass or less.

[0079] (Various additives) The flame-retardant composition may contain various additives such as a diluent, a pigment, a dye, a filler, an ultraviolet absorber, a thickener, a shrinkage reducing agent, an antioxidant, a plasticizer, an aggregate, a flame retardant, a stabilizer, a fiber reinforcing material, an antioxidant, a leveling agent, and an anti-sagging agent.

[0080] <Application> There are no particular limitations on the uses of the polymer and flame-retardant composition of this embodiment, but they can be suitably used in flame-retardant sheets, polymer plates, molded plates, coatings, pressure-sensitive adhesives, adhesives, and the like.

[0081] A preferred embodiment of the polymer and flame-retardant composition of this embodiment is a flame-retardant sheet or board. The flame-retardant sheet or board made using the polymer and flame-retardant composition is excellent in that it does not contain harmful halogen atoms and is less likely to suffer from deterioration in physical properties such as dripping when heated.

[0082] The flame-retardant sheet and board can be processed into any three-dimensional shape by known secondary forming methods, such as vacuum forming and pressure forming. The flame-retardant sheet or board can be preheated to an appropriate temperature using a heating furnace or the like, and then molded into the desired shape using vacuum, compression, air, mechanical pressure, or a combination of these. [Example]

[0083] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. <Synthesis of Compound (A)> Using the synthesis methods of [Production Example 1] and [Example 1], the compounds shown in the following reaction formula were synthesized, and compound (A) represented by general formula (II) (compound represented by chemical formula A-1 in the following reaction formula) was synthesized.

[0084] [ka]

[0085] [Production Example 1] Synthesis of compound (a1) A nitrogen-purged four-neck flask was charged with 15.00 g (116.99 mmol) of 7-octenol, 26.60 g (122.84 mmol) of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and 100 g of toluene, and heated to 60°C. 1.27 g (5.85 mmol) of perbutyl ether was added thereto, and the mixture was stirred for 1 hour. The reaction solution was cooled and concentrated to obtain 45.15 g of a solution containing compound (a1).

[0086] [Example 1] Synthesis of Compound (A) A nitrogen-purged four-neck flask was charged with 40.30 g (116.99 mmol) of compound (a1) obtained in Preparation Example 1, 19.53 g (193.03 mmol) of triethylamine, and 200 g of acetonitrile, and the mixture was stirred at 10°C or below. Then, 14.67 g (140.39 mmol) of methacrylic acid chloride was added dropwise, and the mixture was stirred at room temperature (25°C) for 2 hours. To the reaction solution, 81.5 g of ion-exchanged water and 0.13 g of N,N-dimethylaminopyridine were added, and the mixture was stirred at room temperature. 733.8 g of ethyl acetate was added to the reaction solution to extract the organic layer. The resulting extract was washed with 672.4 g of 4 wt% hydrochloric acid, 1048.6 g of 6 wt% aqueous sodium bicarbonate solution, and 587.9 g of saturated saline, and the organic layer was concentrated. After drying with sodium sulfate, the mixture was purified by silica gel column chromatography to obtain 33.00 g (80.01 mmol, 68.4 mol%) of compound (A) represented by the above chemical formula A-1. 1 The results of H-NMR measurements are shown below.

[0087] 1 H-NMR(400MHz,CDCl3,TMS)δ:7.86(dd,J=8.0,4.8Hz,1H),7.82(dd,J=8.0,3.2Hz,1H),7.77(dd,J=8.0, 0.8Hz,1H),7.59(tt,J=11.6,0.8Hz,1H),7.41(tdd,J=7.2,2.8,0.8Hz,1H),7.28(tt,J=7.2,0.8Hz,1H) ,7.15(td,J=7.2,1.2Hz,1H),7.13(dd,J=8.0,0.8Hz,1H),6.00(dd,J=1.6,0.8Hz,1H),5.45(d,J=1.6Hz ,1H),4.02(t,J=6.8Hz,2H),2.00-1.90(m,J=3.6,2H),1.84(s,3H),1.60-1.48(m,4H),1.32-1,14(m,8H)

[0088] <Creating polymerized plates and test pieces> [Examples 2 to 9], [Comparative Examples 1 and 2] A mixture of the raw materials shown in Table 1 was added to a beaker containing a stirring bar and stirred until completely dissolved to prepare a raw material composition (raw material liquid). The raw material liquid was poured into a cell consisting of two stainless steel plates (2 mm thick, 20 cm square) and a vinyl chloride resin gasket, and polymerized in a hot water bath at 60°C for 6 hours, then in an oven at 130°C for 2 hours to obtain a sheet with a thickness of 3.2 mm. Test pieces measuring 127 mm in length, 13 mm in width, and 3.2 mm in thickness were cut out from the resulting sheet. The test pieces were subjected to the following combustion test and evaluated. The evaluation results of the combustion test are shown in Table 1. In Table 1, blank spaces indicate no blending. Examples 2, 3, and 5 to 9 are examples in which the above-mentioned polymer production method (2) was adopted, and Example 4 is an example in which the above-mentioned polymer production method (1) was adopted.

[0089] <Evaluation (combustion test)> [Burning rate] A 3.2mm thick test piece was left to stand for 18 hours in an environment of 23°C and 50% RH. In accordance with JIS K 6911:1995 A test, the test piece was held horizontally and exposed to a flame from a burner for 30 seconds. The average value of three test pieces was taken, and the flame retardancy was evaluated based on the burning rate (mm / sec) of each. The lower the burning rate, the better the flame retardancy.

[0090] [Drip test] In the burning rate test, whether dripping occurred from the test piece during burning and whether drips fell was judged. If no dripping occurred or drips fell, it was rated as "A", and if drips fell, it was rated as "B".

[0091] [With or without flame-retardant carbonized layer] After the combustion test, the test piece was visually observed, and if the formation of a black flame-retardant carbonized layer due to the phosphorus-containing component was confirmed, it was rated as "present", and if not, it was rated as "absent".

[0092] [Whether or not there is bleed-out] The surfaces of the test pieces prepared as described above were observed, and the presence or absence of bleeding (elution, seepage) of the phosphorus-containing component was judged visually and by touch. If no bleeding was observed, it was rated as "absent," and if bleeding was observed, it was rated as "present."

[0093] [Table 1]

[0094] <Raw materials> The raw materials in Table 1 are as follows: <Compound (A)> Compound (A-1): A compound represented by the above chemical formula A-1 obtained by the synthesis methods of [Production Example 1] and [Example 1].

[0095] <Compound (B)> Compound (B-1): 7-octenyl methacrylate (manufactured by Kuraray Co., Ltd.) (compound represented by the following chemical formula B-1)

[0096] [ka]

[0097] Compound (B-2): Allyl methacrylate (2-propenyl methacrylate, AMA) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[0098] <Polymerizable Monomer (C)> MMA: Methyl methacrylate (Kuraray Co., Ltd.)

[0099] <Phosphite ester compounds (D)> DOPO: 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (Tokyo Chemical Industry Co., Ltd.) Diethyl phosphite: Diethyl phosphite (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[0100] <Radical polymerization initiator (E)> V-65: 2,2'-azobis(2,4-dimethylvaleronitrile) (Fujifilm Wako Pure Chemical Industries, Ltd.) PERHEXA (registered trademark) C: 1,1-di(tert-butylperoxy)cyclohexane (manufactured by NOF Corporation)

[0101] From Example 4 in Table 1, it can be seen that the sheet using the polymer containing the structural unit represented by general formula (I) had a low burning rate, no dripping, a flame-retardant carbonized layer on the surface, and no bleeding out was observed. Thus, it can be seen that Example 4 exhibits excellent flame retardancy. Furthermore, in Examples 2, 3, and 5 to 9, the polymers produced by the polymer production method (2) also exhibited excellent flame retardancy, similar to Example 4. On the other hand, the sheet of Comparative Example 1, which used a polymer not containing the structural unit represented by general formula (I), dripped. Furthermore, the sheet of Comparative Example 2, which used a polymer not containing the structural unit represented by general formula (I), had a high burning rate, and in addition, no flame-retardant charred layer was observed. Thus, Comparative Examples 1 and 2 failed to exhibit excellent flame retardancy. [Industrial Applicability]

[0102] The polymer of the present invention has excellent flame retardancy and is resistant to deterioration in physical properties such as softening upon heating. Therefore, the polymer of the present invention and a flame-retardant composition containing the polymer can be used in applications requiring flame retardancy, and are particularly suitable for use in flame-retardant sheets, flame-retardant boards, flame-retardant paints and coatings, flame-retardant pressure-sensitive adhesives, flame-retardant adhesives, flame-retardant fibers, etc.

Claims

1. A flame-retardant composition comprising a polymer containing a structural unit represented by the following general formula (I): 【Chemistry 1】 (In general formula (I), R １ represents a hydrogen atom or a methyl group. ２ , R ３ R each independently represents any one selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, an alkyloxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkenyloxy group having 2 to 6 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, an aralkyloxy group having 7 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an aryloxy group having 6 to 12 carbon atoms. ２ , R ３ may be bonded to each other, and n is an integer of 0 to 7.

2. The flame retardant composition according to claim 1, wherein n in the general formula (I) is 5.

3. A flame-retardant sheet or board made using the flame-retardant composition according to claim 1 or 2.

4. A compound (A) represented by the following general formula (II): 【Chemistry 2】 (In general formula (II), R １１ represents a hydrogen atom or a methyl group. The structure of the phosphorus atom-containing moiety including R 12 and R 13 has the following structure, and m is 5. 【Transformation 3】

5. A method for producing a polymer, comprising a step of polymerizing a compound (B) represented by the following general formula (III) with a polymerizable monomer (C) in the presence of at least one phosphite ester compound (D) selected from the group consisting of a phosphinite ester compound, a phosphonite monoester compound, and a phosphite diester compound: 【Chemistry 4】 (In general formula (III), R ２１ represents a hydrogen atom or a methyl group, and p is an integer of 0 to 7.

6. The method for producing a polymer according to claim 5 , wherein the compound (B) is represented by the following general formula (IV): 【Transformation 5】 (In general formula (IV), R ３１ represents a hydrogen atom or a methyl group.

7. 7. The method for producing a polymer according to claim 5, wherein the amount of the phosphite ester compound (D) added is 40 to 160 mol % relative to 100 mol % of the compound (B).

8. A composition comprising a compound (B) represented by the following general formula (III), a polymerizable monomer (C), and at least one phosphite ester compound (D) selected from the group consisting of phosphinite ester compounds, phosphonite monoester compounds, and phosphite diester compounds: 【Transformation 6】 (In general formula (III), R ２１ represents a hydrogen atom or a methyl group, and p is an integer of 0 to 7.

9. The composition according to claim 8, wherein the compound (B) is represented by the following general formula (IV): 【Transformation 7】 (In general formula (IV), R ３１ represents a hydrogen atom or a methyl group.

10. 10. The composition according to claim 8, wherein the content of the phosphite ester compound (D) is 40 to 160 mol% relative to 100 mol% of the compound (B).

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