Method for producing a molten compound and molten compound

Abstract

Provided are a method for producing a melted / mixed composition and a melted / mixed composition. The method comprises a step for melting / mixing a 3-methyl-1-butene polymer and an alkyl radical scavenger. This melting / mixing is performed at 300°C to 380°C. In this method, either an inert gas is introduced into a melting / mixing device and the melting / mixing is performed, or the inside of a melting / mixing device is vacuum degassed and the melting / mixing is performed.

Description

[Technical Field]

[0001] The present invention relates to a method for producing a melt-blown composition containing a 3-methyl-1-butene polymer and to a melt-blown composition. [Background technology]

[0002] 3-methyl-1-butene polymers have a high melting point among thermoplastic polyolefin resins and are useful as heat-resistant polyolefins. However, because 3-methyl-1-butene polymers have a high melting point, they must be melt-mixed at high temperatures. As a result, during melt-mixing, the 3-methyl-1-butene polymer deteriorates (decomposes) due to heat and oxidation, leading to problems such as a decrease in the viscosity of the molten material and a decrease in the mechanical properties of the molded product. Therefore, Patent Document 1 examines combinations of antioxidants, taking into account that the effect of antioxidants is lost in a short time. Patent Document 2 examines the types and combinations of antioxidants to be added in order to prevent oxidative degradation of 3-methyl-1-butene polymers during melt kneading.

[0003] On the other hand, alkyl radical scavengers are sometimes used to ensure the thermoforming stability of polyolefins. For example, Patent Document 3 describes a polyolefin composition containing a polyolefin, a hindered phenol compound, an acrylate compound, and a phosphorus compound to ensure heat resistance during high-temperature processing when forming fibers, etc. Patent Document 4 also describes the oxidative stabilization of polyolefin-based thermoplastic resins, and describes a composition containing a thermoplastic resin, a phenol antioxidant, an aromatic amine and / or an N,N'-substituted oxamide antioxidant, and a lactone antioxidant. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 181844 / 1983 [Patent Document 2] Japanese Patent Application Publication No. 06-100742 [Patent Document 3] Japanese Patent Application Publication No. 05-059227 [Patent Document 4] International Publication No. 2002 / 31038 [Overview of the project] [Problems that the invention aims to solve]

[0005] Furthermore, to prevent thermal degradation of the 3-methyl-1-butene polymer during melt-mixing, it is advisable to minimize the melt-mixing time. However, the required melting and mixing time varies depending on the melting and mixing machine, and the larger the melting and mixing machine, the longer the melting and mixing time tends to be. Therefore, not using a large melting and mixing machine in order to shorten the melting and mixing time is disadvantageous from a productivity standpoint. Thus, in practical terms, it is difficult to avoid exposing 3-methyl-1-butene polymers to high temperatures for extended periods. Furthermore, if the resin composition has poor thermal stability, reproducibility cannot be ensured across different mixing equipment, making it difficult to stably manufacture molded products. In addition, even if the melt-mixing time is short, it is unavoidable that the cumulative melt-mixing time will increase if scrap material is recycled repeatedly.

[0006] As mentioned above, studies are underway to use antioxidants and alkyl radical scavengers, etc., to prevent thermal degradation of 3-methyl-1-butene polymers. However, Patent Documents 1 and 2 do not examine the stability of physical properties against heat over long periods during melt mixing. In fact, when the inventors tested the methods described in Patent Documents 1 and 2, the compositions containing 3-methyl-1-butene polymers showed insufficient long-term thermal stability. In Patent Document 3, no examination has been conducted using a 3-methyl-1-butene-based polymer as the polyolefin. As a result of the inventors' tests, even with the method described in Patent Document 3, a composition containing a 3-methyl-1-butene-based polymer could not obtain long-term thermal stability. Also, in Patent Document 4, no examination has been conducted using a 3-methyl-1-butene-based polymer, and only the thermal stability at a temperature lower than the melting point of the 3-methyl-1-butene-based polymer has been examined. Therefore, even with the method described in Patent Document 4, long-term thermal stability cannot be expected for a composition containing a 3-methyl-1-butene-based polymer.

[0007] Therefore, an object of the present invention is to provide a method for producing a melt-kneaded composition whose physical properties can be maintained even after long-term melt-kneading, and a melt-kneaded composition. More specifically, an object of the present invention is to provide a method for producing a melt-kneaded composition whose physical properties can be maintained even after long-term melt-kneading, has good productivity, and can obtain a molded body having good mechanical properties, and a melt-kneaded composition. Other problems can be grasped by those skilled in the art from the disclosure of this specification.

Means for Solving the Problems

[0008] As a result of intensive studies to solve the above problems, the inventors of the present invention have conceived the following present invention and found that the problems can be solved. That is, the present invention is as follows:

[0009] [1] A method for producing a melt-kneaded composition, comprising a step of melt-kneading a 3-methyl-1-butene-based polymer and an alkyl radical scavenger at 300 to 380°C in a state of lower oxygen than the atmosphere. [2] The method for producing a melt-kneaded composition according to [1] above, further comprising a step of injecting an inert gas into the inside of the melt-kneader, and performing the melt-kneading in the melt-kneader. [3] The method for producing a melt-kneaded composition according to [1] or [2] above, further comprising a step of depressurizing and degassing the inside of the melt-kneader, and performing the melt-kneading in the melt-kneader. [4] A process of melt-kneading a 3-methyl-1-butene-based polymer and an alkyl radical scavenger is included, The melt-kneading is carried out at 300 to 380 °C, and An inert gas is injected into the melt-kneader to carry out the melt-kneading, or The inside of the melt-kneader is depressurized and degassed to carry out the melt-kneading, A method for producing a melt-kneaded composition. [5] The melt-kneading is carried out for 1 to 15 minutes, and the method for producing a melt-kneaded composition according to any one of the above [1] to [4]. [6] The 3-methyl-1-butene-based polymer is at least one selected from the group consisting of a 3-methyl-1-butene homopolymer and a copolymer of 3-methyl-1-butene and an α-olefin having 2 to 20 carbon atoms, and the method for producing a melt-kneaded composition according to any one of the above [1] to [5]. [7] In the copolymer, the content ratio of the structural unit derived from the α-olefin is more than 0 mol% and 20 mol% or less, and the method for producing a melt-kneaded composition according to the above [6]. [8] The alkyl radical scavenger contains at least one selected from the group consisting of an acrylic phenol compound and a benzofuranone compound, and the method for producing a melt-kneaded composition according to any one of the above [1] to [7]. [9] The acrylic phenol compound is represented by the following general formula (I), and the method for producing a melt-kneaded composition according to the above [8]. [Chemical formula] (In general formula (I), R 1 represents a hydrogen atom or a methyl group, R 2 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R 3 , R 4 , R 5 and R 6 each independently represents an alkyl group having 1 to 9 carbon atoms.)

[10] The benzofuranone compound is represented by the following general formula (II), and the method for producing a melt-kneaded composition according to the above [8] or [9]. [Chemical formula] (In general formula (II), R 7 and R 8 each independently represent an alkyl group having 1 to 4 carbon atoms, and R 9 and R 10 each independently represent an alkyl group having 1 to 9 carbon atoms.)

[11] The method for producing a melt-kneaded composition according to any one of [1] to

[10] above, wherein the amount of the alkyl radical scavenger is 0.01 to 1.00 parts by mass with respect to 100 parts by mass of the above 3-methyl-1-butene polymer.

[12] The method for producing a melt-kneaded composition according to any one of [1] to

[11] above, wherein in the step of melt-kneading, at least one antioxidant selected from the group consisting of a phenolic antioxidant and a phosphorus-based antioxidant is further blended to perform the melt-kneading.

[13] A melt-kneaded composition produced by the method for producing a melt-kneaded composition according to any one of [1] to

[12] above. [Advantages of the Invention] <000012​​​​​​​​​​​​In this specification, when a numerical range such as "XX~YY" is mentioned, it means "XX or greater and YY or less."

[0012] The molten compound and the method for producing the same according to this embodiment are The process involves melt-kneading a 3-methyl-1-butene polymer with an alkyl radical scavenger. The melting and mixing is carried out at 300-380°C, and, In the melting and mixing process, melting and mixing is performed by injecting an inert gas into the melting and mixing machine, or by degassing the inside of the melting and mixing machine under reduced pressure. It is characterized by the following: Because 3-methyl-1-butene polymers have a high melting point of approximately 280°C or higher, even compositions containing antioxidants recommended for high-temperature molding in this field sometimes fail to maintain the stability of their physical properties due to thermal degradation during high-temperature melt-kneading at approximately 300°C or higher, leading to a decrease in the mechanical properties of the molded article. The inventors focused on the fact that 3-methyl-1-butene polymers can undergo decomposition initiated by alkyl radicals (R·) during high-temperature melt-kneading, and developed a composition in which an alkyl radical scavenger is added to the 3-methyl-1-butene polymer. However, even with the addition of an alkyl radical scavenger, it was not easy to suppress thermal degradation due to high-temperature melt-kneading. Therefore, the inventors considered that even with the use of an alkyl radical scavenger, decomposition by oxygen proceeds before thermal decomposition, and focused on the atmospheric conditions inside the apparatus during melt-kneading. As a result, we found that adding an alkyl radical scavenger to the 3-methyl-1-butene polymer, in addition to lowering the oxygen concentration inside the melting and mixing machine, is effective. Further investigations led to the present invention. In this embodiment, the term "long time" refers to, for example, about 15 minutes. The "melt-mixing step" typically includes a step of melt-mixing the 3-methyl-1-butene polymer and the alkyl radical scavenger inside a melt-mixing machine. The method for producing the melt-mixed composition or the "melt-mixing step" may include either a step of injecting an inert gas into the melt-mixing machine or a step of degassing the inside of the melt-mixing machine under reduced pressure, or both steps. For example, the step of injecting an inert gas may be performed upstream of the melt-mixing machine, and the step of degassing under reduced pressure may be performed downstream of that. The "injection step" or the "degassing under reduced pressure step" may be performed before melt-mixing the 3-methyl-1-butene polymer and the alkyl radical scavenger, for example, before the start of heating, before the start of shearing, or before the start of both heating and shearing, and preferably continues during melt-mixing.

[0013] <Method for producing a molten compound> [3-methyl-1-butene polymer] The 3-methyl-1-butene polymer may be a 3-methyl-1-butene homopolymer or a copolymer of 3-methyl-1-butene and an unsaturated hydrocarbon. Examples of the unsaturated hydrocarbon include α-olefins, and from the viewpoint of good copolymerizability, α-olefins having 2 to 20 carbon atoms are preferred. From the viewpoint of favorably exhibiting the physical properties of 3-methyl-1-butene, the 3-methyl-1-butene polymer is preferably at least one selected from the group consisting of 3-methyl-1-butene homopolymers and copolymers of 3-methyl-1-butene and α-olefins having 2 to 20 carbon atoms.

[0014] When the 3-methyl-1-butene polymer is the copolymer described above, the content of structural units derived from α-olefins in the copolymer is preferably more than 0 mol% and 20 mol% or less. From the viewpoint of favorably exhibiting the physical properties of α-olefins, the content of structural units derived from α-olefins in the copolymer is more preferably 0.1 mol% or more, and even more preferably 0.5 mol% or more. Furthermore, from the viewpoint of suitably maintaining the physical properties of 3-methyl-1-butene, the content of structural units derived from α-olefins in the copolymer is more preferably 15 mol% or less, and even more preferably 10 mol% or less. The proportion of structural units derived from α-olefins in the copolymer can be determined by Fourier transform infrared spectrophotometer (FT-IR). Specifically, it can be measured by the method described in the examples.

[0015] From the viewpoint of favorably exhibiting the physical properties of 3-methyl-1-butene, the α-olefin having 2 to 20 carbon atoms is preferably an α-olefin having 4 to 16 carbon atoms, and more preferably an α-olefin having 4 to 12 carbon atoms. Furthermore, the α-olefin having 2 to 20 carbon atoms may be linear or branched.

[0016] Examples of α-olefins having 2 to 20 carbon atoms include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, vinylcyclohexene, vinylnorbornane, and the like. α-olefins having 2 to 20 carbon atoms may be used individually or in combination of two or more types.

[0017] In this embodiment, the method for producing the 3-methyl-1-butene polymer is not particularly limited and can be produced using well-known catalysts such as Ziegra-Natta catalysts and metallocene catalysts. The 3-methyl-1-butene polymer can be produced, for example, by homopolymerizing 3-methyl-1-butene in the presence of a catalyst, or by copolymerizing 3-methyl-1-butene with the above-mentioned α-olefin, as described in Japanese Patent Publication No. 61-103910, to obtain it as a powder. The stereoregularity of the 3-methyl-1-butene polymer may be isotactic or syndiotactic. Furthermore, the copolymer may be a random copolymer, a block copolymer, or an alternating copolymer.

[0018] [Alkyl radical scavenger] In this embodiment, "alkyl radical scavenger" refers to a compound that reacts with alkyl radicals derived from 3-methyl-1-butene polymers and stabilizes the alkyl radicals, thereby suppressing subsequent chain reactions of carbon-carbon bond dissociation. The alkyl radical scavenger preferably contains at least one selected from the group consisting of acrylicphenol compounds and benzofuranone compounds. Alkyl radical scavengers may be used individually or in combination of two or more types.

[0019] <Acrylphenol compounds> The acrylicphenol compound used in this embodiment can be represented, for example, by the following general formula (I).

[0020] [ka]

[0021] In general formula (I), R 1 R represents a hydrogen atom or a methyl group. 2 R represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 3 ,R 4 ,R 5 and R 6 Each of these independently represents an alkyl group having 1 to 9 carbon atoms. Examples of alkyl groups having 1 to 3 carbon atoms include methyl, ethyl, n-propyl, and isopropyl groups. The alkyl group having 1 to 9 carbon atoms may be linear or branched. Examples of alkyl groups having 1 to 9 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, 1,1-dimethylpropyl group, 1,2-dimethylpropyl group, 2,2-dimethylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, and n-nonyl group. R 1 Preferably, it is a hydrogen atom. R 2 This is preferably a hydrogen atom or a methyl group, more preferably a methyl group. R 3 ,R 4 ,R 5 and R 6 Each of these is independently preferably an alkyl group having 3 to 8 carbon atoms, more preferably an alkyl group having 5 carbon atoms, and even more preferably a 1,1-dimethylpropyl group.

[0022] Examples of acrylicphenol compounds represented by general formula (I) include 2,4-di-t-amyl-6-[1-(3,5-di-t-amyl-2-hydroxyphenyl)ethyl]phenyl acrylate, 2,4-di-t-butyl-6-[1-(3,5-di-t-butyl-2-hydroxyphenyl)ethyl]phenyl acrylate, and 2-t-butyl-6-[(3-t-butyl-2-hydroxy-5-methylphenyl)methyl]-4-methylphenyl acrylate. A commercially available alkyl radical scavenger may be used, and examples of acrylicphenol compounds represented by general formula (I) include the trade names "SumiLizer® GS" and "SumiLizer® GM" manufactured by Sumitomo Chemical Co., Ltd.

[0023] <Benzofuranone compounds> The benzofuranone compound used in this embodiment can be represented, for example, by the following general formula (II).

[0024] [ka]

[0025] In general formula (II), R 7 and R 8 Each of these independently represents an alkyl group having 1 to 4 carbon atoms, and R 9 and R 10 Each of these independently represents an alkyl group having 1 to 9 carbon atoms. Examples of alkyl groups having 1 to 4 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, and t-butyl groups. C1-C9 alkyl groups may be linear or branched. Examples of C1-C9 alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 2,2-dimethylpropyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, and n-nonyl groups. R 7 and R 8 Each of these is independently preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group. R 9 and R 10 Each of these is independently preferably an alkyl group having 1 to 4 carbon atoms, more preferably a t-butyl group.

[0026] Examples of benzofuranone compounds represented by general formula (II) include 5,7-di-t-butyl-3-(3,4-di-methyl-phenyl)-3H-benzofuran-2-one, 5,7-di-t-butyl-3-(3,4-di-propyl-phenyl)-3H-benzofuran-2-one, and 4-t-butyl-2-(5-t-butyl-2-oxo-3H-benzofuran-3-yl)phenyl-3,5-di-t-butyl-4-hydroxybenzoate. A commercially available alkyl radical scavenger may be used. Examples of benzofuranone compounds represented by general formula (II) include "Irganox® HP-136" from BASF and "Revonox® 501" from Chiteco.

[0027] <Blend amount> The amount of alkyl radical scavenger blended with 100 parts by mass of 3-methyl-1-butene polymer is preferably 0.01 to 1.00 parts by mass. If the amount of alkyl radical scavenger is within the above numerical range, the stability of the physical properties of the molten-mixed composition can be maintained during melt-mixing. Furthermore, there is no risk of the alkyl radical scavenger bleeding out or of the desired physical properties of the resin composition being impaired, such as deterioration of hygroscopicity. In addition, there is no risk of decomposition gas generation during melt molding, which could lead to molding defects.

[0028] From the viewpoint of more easily exhibiting the effects of the present invention, the amount of alkyl radical scavenger blended with 100 parts by mass of 3-methyl-1-butene polymer is more preferably 0.02 parts by mass or more, and even more preferably 0.05 parts by mass or more. Furthermore, from the viewpoint of balancing the effects and economics of the present invention, the amount of alkyl radical scavenger blended with 100 parts by mass of 3-methyl-1-butene polymer is more preferably 0.80 parts by mass or less, and even more preferably 0.70 parts by mass or less. When two or more alkyl radical scavengers are included, the amount of alkyl radical scavengers included refers to the total amount of alkyl radical scavengers included.

[0029] [Antioxidant] From the viewpoint of heat aging resistance, at least one antioxidant selected from the group consisting of phenolic antioxidants and phosphorus-based antioxidants may be further added during the melt-kneading process. Alternatively, the melt-kneading process may be carried out without adding any antioxidants. Antioxidants may be used individually or in combination of two or more types.

[0030] <Phenol-based antioxidants> Phenolic antioxidants include, for example, pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 1,3,5-tris(3,5-di-t-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 1,3,5-tris[(4-t-butyl-3-hydroxy-2,6-xylyl)methyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, and octa Decyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, thiodiethylene-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], N,N'-Hexane-1,6-diylbis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionamide], 3,3',3'',5,5',5''-Hexa-t-butyl-α,α',α''-(mesitylene-2,4,6-triyl)tri-p-cresol, ethylenebis (Oxyethylene)bis[3-(5-t-butyl-4-hydroxy-m-tolyl)propionate], hexamethylene-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 2,6-di-t-butyl-4-[4,6-bis(octylthio)-1,3,5-triazine-2-ylamino]phenol, 3,9-bis[2-(3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy)-1,1-dimethylethyl]-2, Examples include 4,8,10-tetraoxaspiro(5,5)undecane, 4,4',4''-(1-methylpropanyl-3-ylidene)tris(6-t-butyl-m-cresol), 6,6'-di-t-butyl-4,4'-butylidenedi-m-cresol, octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)-propinate, and 3,5-bis-(1,1-dimethylethyl)-4-hydroxy-C7-C9 branched alkyl esters of benzenepropionic acid.

[0031] Commercially available phenolic antioxidants may be used, such as ADEKA's "ADEKA Stab® AO series" and BASF Japan's "Irganox® series."

[0032] <Phosphorus-based antioxidants> Phosphorus-based antioxidants, for example, 3,9-bis(2,6-di-t-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, tetrakis(2,4-di-t-butylphenyl)-4,4'-biphenylenephosphonite, 2,2-methylenebis(4,6-di-t-butylphenyl)octylphosphite, tris(2,4-di-t-butylphenyl)phosphite, bis[2,4-bis(1,1-dimethylethyl)-6-methylphenyl]ethyl ester phosphite, bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, bis(2 ,4-Dicumylphenyl)Pentaerythritol-diphosphite, Di-t-butyl-m-cresyl-phosphonite, Diethyl[(3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl)methyl]phosphonate, Tris(2,4-di-t-butylphenyl)phosphite, Tetrakis(2,4-di-t-butylphenyl)-4,4'-biphenylenediphosphonite, 3,9-Bis(octadechioxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, Tris(2,4-di-t-butylphenyl)phosphite, Tris(nonylphenyl)phosphite, Tetra-C 12 -C 15 Examples include alkyl[propane-2,2-diylbis(4,1-phenylene)]bis(phosphite), 2-ethylhexyldiphenylphosphite, isodecyldiphenylphosphite, trisisodecylphosphite, triphenylphosphite, and 3,9-bis[2,4-bis(1-methyl-1-phenylethyl)phenoxy]-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane.

[0033] A commercially available phosphorus-based antioxidant may be used, for example, "ADEKA Stab® PEP series" and "ADEKA Stab® HP series" from ADEKA Corporation, "Irgafos® series" from BASF Japan, and "HOSTANOX® P-EPQ" from Clariant Corporation.

[0034] <Other antioxidants> Furthermore, in the melt-mixing process, other antioxidants other than phenolic antioxidants and phosphorus-based antioxidants may be added, as long as they do not impair the effects of the present invention. Examples of antioxidants other than phenolic antioxidants and phosphorus-based antioxidants include sulfur-based antioxidants and amine-based antioxidants.

[0035] <Blend amount> From the viewpoint of exhibiting better heat aging resistance, the amount of antioxidant added per 100 parts by mass of 3-methyl-1-butene polymer is preferably 0.01 parts by mass or more, more preferably 0.10 parts by mass or more. Furthermore, from an economic standpoint, the amount of antioxidant blended per 100 parts by mass of 3-methyl-1-butene polymer is preferably 1.00 part by mass or less, more preferably 0.80 parts by mass or less. When two or more antioxidants are included, the amount of antioxidants mentioned above refers to the total amount of antioxidants included.

[0036] [Other additives] In the melt-mixing process, other additives may be further added in addition to the 3-methyl-1-butene polymer, alkyl radical scavenger, and antioxidant before melt-mixing. Other additives include, for example, antacids, fillers, light stabilizers, antistatic agents, flame retardants, pigments, polymerization inhibitors, heavy metal deactivators, ultraviolet absorbers, nucleating agents, clearing agents, lubricants, fluorescent whitening agents, and rust inhibitors. Other additives may be used individually or in combination of two or more.

[0037] Antacids From the viewpoint of suppressing deterioration caused by acidic components generated from residual metals, it is preferable to further incorporate an antacid during the melt-mixing process. Antacids include barium laurate, calcium stearate, zinc stearate, magnesium stearate, aluminum stearate, zinc oleate, and magnesium 12-hydroxystearate. Antacids may be used individually or in combination of two or more types.

[0038] The amount of antacid added per 100 parts by mass of 3-methyl-1-butene polymer can be appropriately determined according to the intended use of the melt-mixed composition, and may be, for example, 0.01 to 200 parts by mass.

[0039] <Fillers> Depending on the intended use of the melt-mixed composition, in addition to the 3-methyl-1-butene polymer and alkyl radical scavenger, fillers may be further added during the melt-mixing process. Alternatively, fillers may be added to the melt-mixed composition and then melt-mixed again. Examples of fillers include fibrous compounds such as glass fibers, alumina fibers, resin fibers, carbon fibers, and cellulose fibers; plate-like compounds such as mica, talc, montmorillonite, and aluminum plates; spherical compounds such as glass beads, shirasu balloons, and acrylic balloons; needle-like compounds such as acicular metal titanate, wollastonite, acicular silica, and tin oxide; and powdered compounds such as powdered metal titanate, pulverized wood chips, titanium dioxide, calcium carbonate, silica, and alumina. These fillers may be surface-treated with, for example, a silane coupling agent. Compatibilizers may also be used to improve the dispersibility of the fillers. The filler may be used alone or in combination of two or more types.

[0040] The amount of filler added to 100 parts by mass of 3-methyl-1-butene polymer can be appropriately determined according to the intended use of the melt-mixed composition, and may be, for example, 0.01 to 300 parts by mass.

[0041] [Melting and mixing conditions] <Inactive atmosphere> The manufacturing method of this embodiment includes a step of melt-mixing a 3-methyl-1-butene polymer and an alkyl radical scavenger at 300 to 380°C in a state of lower oxygen than atmospheric pressure. The manufacturing method further includes a step of injecting an inert gas into the melt-mixing machine, and it is preferable to perform the melt-mixing inside the melt-mixing machine. By injecting an inert gas, preferably continuously, a low-oxygen state can be achieved inside the melt-mixing machine. The manufacturing method further includes a step of degassing the inside of the melt-mixing machine under reduced pressure, and it is preferable to perform the melt-mixing inside the melt-mixing machine. By degassing under reduced pressure, preferably continuously, a low-oxygen state can be achieved inside the melt-mixing machine. The manufacturing method further includes a step of injecting an inert gas into the inside of the melt-mixing machine and a step of degassing the inside of the melt-mixing machine under reduced pressure, and it is preferable to perform the melt-mixing inside the melt-mixing machine. In one embodiment of the manufacturing method of this embodiment, in the step of melt-mixing a 3-methyl-1-butene polymer and an alkyl radical scavenger, melt-mixing is performed by injecting an inert gas into the melt-mixer, or by degassing the inside of the melt-mixer under reduced pressure.

[0042] In this embodiment, the manufacturing method is designed to suppress the deterioration of the physical properties of the melt-mixed composition due to oxygen, effectively utilize the function of the alkyl radical scavenger, and produce a molded article with good mechanical properties. Therefore, it is important to perform the melt-mixing under an inert atmosphere or a low-oxygen state. In this embodiment, "low oxygen state" refers to a state in which the oxygen concentration inside the melting mixer is lower than before vacuum degassing, due to degassing the inside of the melting mixer under reduced pressure. In the "inert atmosphere" state, the oxygen concentration inside the melting mixer is lower than before the injection of inert gas, due to the injection of inert gas into the melting mixer. Therefore, the concept of "low oxygen state" may include the "inert atmosphere" state. In the "low oxygen state," the oxygen concentration inside the melting mixer is preferably 5% or less, more preferably 2% or less, and even more preferably 1% or less. The oxygen concentration is measured using an oxygen concentration meter, preferably a diaphragm-type galvanic type, more preferably a diaphragm-type galvanic cell type, or a galvanic cell type oxygen concentration meter. More specifically, the oxygen concentration can be measured by the method described in the examples. For example, the "XP-3180E" (diaphragm-type galvanic cell type) and its successor, the "XP-3380II-E" (galvanic cell type), manufactured by Shin-Cosmos Electric Co., Ltd., can be used as oxygen concentration meters.

[0043] The method of melting and mixing by injecting an inert gas into the melting and mixing machine may, for example, involve injecting the inert gas into the melting and mixing machine while adding each component, or after adding each component into the melting and mixing machine, preferably before starting to raise the temperature or before starting to shear, more preferably before starting to raise the temperature and before starting to shear, or after injecting the inert gas into the melting and mixing machine, each component may be added from a sealed supply unit and then melted and mixed. Furthermore, the inert gas may be continuously injected into the melting and mixing machine while melting and mixing is in progress. The method for inert gas injection can be carried out according to the equipment installed in each melting and mixing machine. For example, it may be done from a gas supply unit for inert gas etc. installed in the melting and mixing machine, from a supply unit for each component installed in the melting and mixing machine, or from a gas vent installed in the melting and mixing machine. As long as the inert gas can be injected throughout the entire process, from the supply unit to the heating unit where melting and mixing takes place, there are no restrictions on the injection method. Examples of inert gases include nitrogen gas, helium gas, neon gas, argon gas, krypton gas, and carbon dioxide gas. From the viewpoint of high availability and versatility, nitrogen gas is preferred.

[0044] The method of degassing the inside of a melting mixer under reduced pressure and then melting and mixing may, for example, involve adding each component while degassing the inside of the melting mixer under reduced pressure and then performing the melting and mixing; or, after adding each component to the inside of the melting mixer, preferably before starting to raise the temperature or before starting to shear, more preferably before starting to raise the temperature and before starting to shear, the inside of the melting mixer may be degassed under reduced pressure and then melting and mixing may be performed by adding each component from a sealed supply section after degassing the inside of the melting mixer under reduced pressure. Furthermore, during melting and mixing, degassing the inside of the melting mixer may be performed intermittently or continuously. The method for degassing the inside of a melting and mixing machine under reduced pressure can be carried out according to the equipment provided in each melting and mixing machine, for example, by using a vacuum vent. For degassing under reduced pressure, for example, a vacuum pump can be used. There are no restrictions on the method of vacuum degassing inside the melting and mixing machine, as long as melting and mixing can be performed in a low-oxygen state. When performing degassing under reduced pressure, the inside of the melting and mixing machine can be kept in a vacuum state of, for example, 50 kPa or less and 0.1 kPa or more.

[0045] The melting and mixing machine can be a single-screw extruder, multi-screw extruder, kneader, Banbury mixer, etc., equipped with facilities that can melt and mix by injecting an inert gas into the melting and mixing machine, or facilities that can melt and mix by degassing the inside of the melting and mixing machine under reduced pressure.

[0046] The above-mentioned injection of inert gas and degassing under reduced pressure may be used in combination. In this case, it is preferable to inject the inert gas upstream of the melting and mixing machine before or together with the raw materials, while performing degassing under reduced pressure downstream of the inert gas. More preferably, both the injection of inert gas and degassing under reduced pressure are continued during melting and mixing.

[0047] <Temperature and time, etc.> In this embodiment, the manufacturing method involves performing the above-mentioned melt mixing at 300 to 380°C. If the melting and mixing temperature is below 300°C, the 3-methyl-1-butene polymer will not melt sufficiently, resulting in insufficient dispersion of the alkyl radical scavenger and other additives. If the melting and mixing temperature exceeds 380°C, the decomposition of raw materials such as the 3-methyl-1-butene polymer and alkyl radical scavenger becomes significant, and the full effect of the invention cannot be obtained. From the viewpoint of sufficiently dispersing alkyl radical scavengers and additives throughout the 3-methyl-1-butene polymer, the melting and kneading temperature is preferably 300°C or higher, more preferably 310°C or higher. Furthermore, from the viewpoint of suppressing significant decomposition of the raw materials, the melting and mixing temperature is preferably 380°C or lower, and more preferably 360°C or lower.

[0048] The melting and mixing time can be adjusted according to the size of the mixing apparatus, etc. For example, it may be 1 to 15 minutes, but is not limited to this numerical range. In this embodiment, "melting and mixing time" refers to the time the mixer is rotating in a batch-type mixer, and the residence time of the raw materials in the apparatus in the case of a continuous extrusion-type mixer. It is preferable that the aforementioned low-oxygen state is continuously maintained throughout the entire melting and mixing time. The manufacturing method of this embodiment is less prone to deterioration of physical properties due to high-temperature melt mixing. Therefore, the longer the melt mixing time (approximately 15 minutes in this embodiment), the more the physical property stability of the molten material is maintained, and the more easily the effects of the present invention are demonstrated, such as the ability to produce a melt-mixed resin composition with good mechanical properties in a highly productive manner. As the size of the melting and mixing machine increases, the production volume increases, and the melting and mixing time tends to lengthen, which increases the risk of deterioration in the physical properties of the melted and mixed composition. However, with the manufacturing method of this embodiment, the stability of the physical properties can be maintained, so a melted and mixed resin composition with good mechanical properties can be produced with good productivity.

[0049] The mixer rotation speed during melting and mixing may be 80 rpm or more, or 100 rpm or more, or 400 rpm or less, or 350 rpm or less. After melting and mixing, the molten mixture is removed from the melting and mixing machine and cooled.

[0050] <Molten and mixed composition> This embodiment provides a molten compound composition produced by the method for producing a molten compound composition described above. Regarding the molten compound produced by the above-described method for manufacturing molten compound compositions, for example, a portion of the 3-methyl-1-butene polymer may decompose due to the high temperature during molten compounding, and in some cases due to high temperature and shear. Furthermore, since the amount of alkyl radical scavenger is small, it is difficult to accurately define the decomposed alkyl radical scavenger. Therefore, it is currently practically difficult to clearly analyze and identify the structure of the molten compound composition, including the decomposition products and reaction products between the 3-methyl-1-butene polymer and the alkyl radical scavenger. Consequently, since it is impossible or impractical to directly identify the molten compound composition by its specific chemical structure with current technology, it is identified by its manufacturing method. Nevertheless, as illustrated in the Examples section, the molten compound produced by the above-described method for manufacturing molten compound compositions clearly maintains greater physical stability compared to molten compound compositions produced by methods other than the above-described method. Furthermore, it is possible to detect some or all of the undegraded alkyl radical scavengers present in the molten compound.

[0051] When no antioxidant is included, the total content of the 3-methyl-1-butene polymer and alkyl radical scavenger in the molten compound is preferably 99.0% by mass or more, more preferably 99.5% by mass or more. The upper limit of this total content is not limited as long as the effects of the invention are not impaired, and may be, for example, 100% by mass or less, or 99.9% by mass or less. Furthermore, when the above-mentioned antioxidant is included, the total content ratio of the 3-methyl-1-butene polymer, alkyl radical scavenger, and antioxidant in the molten compound is preferably 99.0% by mass or more, more preferably 99.5% by mass or more. The upper limit of this total content ratio is not limited as long as the effects of the invention are not impaired, and may be, for example, 100% by mass or less, or 99.9% by mass or less. In this specification, the "content ratio" mentioned above shall be calculated based on the amount of each component used in the molten compound. As mentioned above, after melt mixing, some or all of the blended 3-methyl-1-butene polymer and alkyl radical scavenger have reacted, decomposed, or evaporated, making it difficult to determine the exact content ratio of each component.

[0052] <Melting point> The melt-mixed composition of this embodiment preferably has a melting point of 280 to 310°C. If the melting point of the melt-mixed composition is within the above range, it exhibits excellent heat resistance and can suitably demonstrate the properties of the 3-methyl-1-butene polymer. Furthermore, the melting point of the molten compound of this embodiment is almost the same as the melting point of the 3-methyl-1-butene polymer used as a raw material. Therefore, in this specification, the melting point of the 3-methyl-1-butene polymer used as a raw material can be considered as the melting point of the molten compound. The melting point can be measured by the method described in the examples.

[0053] <Melting viscosity> The melt-mixed composition of this embodiment was prepared at a barrel temperature of 320°C and a shear rate of 1220 sec. -1The melt viscosity is preferably 10 to 1000 Pa·s, more preferably 20 to 500 Pa·s. If the melt viscosity of the molten compound is 10 Pa·s or higher, the strength of the molded article will be good. Also, if the melt viscosity of the molten compound is 1000 Pa·s or lower, the fluidity during molding will be good. The melt viscosity of the molten compound can be measured by the method described in the examples.

[0054] <Forming method> Depending on the intended use of the molten-mixed composition, the process of melt-mixing a 3-methyl-1-butene polymer, an alkyl radical scavenger, and other additives such as antioxidants and fillers as needed may be carried out in succession with the molding process. Alternatively, the molten-mixed composition may be removed and then melt-molded again. Common molding methods such as injection molding, extrusion molding, blow molding, and vacuum molding can be used.

[0055] <Breaking strength> The molten compound of this embodiment has a fracture strength of 10 MPa or more, more preferably 25 MPa or more, measured in accordance with JIS K 7161-1:2014 for its molded article. A fracture strength of 10 MPa or more indicates good mechanical strength. The breaking strength can be measured by the method described in the examples. [Examples]

[0056] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to these.

[0057] <Measurement and Evaluation Methods> Various physical properties were measured or evaluated using the following methods. [Percentage of constituent units derived from comonomers] In Production Examples 1 and 2, the content of structural units derived from α-olefins (comonomers) other than 3-methyl-1-butene in the 3-methyl-1-butene copolymer was determined by IR measurement using the ATR method with an FT-IR analyzer (Ailent Technolies, instrument name "cary 600 series FTIR spectrometer"), as follows. The bending vibration of 1,461 cm² originating from the main chain methylene group of the 3-methyl-1-butene homopolymer. -1 The peak area and the bending vibration of 727 cm² originating from the side-chain methylene group of the α-olefin homopolymer. -1 A calibration curve was created from the ratio of the peak area to the respective resin addition ratio. The 3-methyl-1-butene copolymer obtained in the production example was subjected to the above IR measurement, and the obtained measurement values ​​were inserted into the above calibration curve to determine the content ratio of structural units derived from α-olefins other than 3-methyl-1-butene.

[0058] [Melting point] The copolymers or homopolymers obtained in the production examples were heated from 30°C to 320°C at a rate of 10°C / min under a nitrogen flow rate (100 mL / min) using a differential scanning calorimetry instrument (TA Instruments "DSC25"). After holding at 320°C for 5 minutes, the temperature was lowered to -70°C at a rate of 10°C / min. The melting points were measured when the temperature was raised to 320°C at a rate of 10°C / min after holding at -70°C for 5 minutes.

[0059] [Melting viscosity] In Examples 1, 7, and 8, after blending the components shown in Table 1, a capillary rheometer (Capillography 1C, manufactured by Toyo Seiki Seisakusho Co., Ltd.) was used to measure the results at a barrel temperature of 320°C and a shear rate of 1220 sec. -1 The melt viscosity (Pa·s) of the molten compound was measured under the conditions of (capillary: inner diameter 1.0 mm × length 10 mm, extrusion speed 10 mm / min).

[0060] [Stability of physical properties during molten compounding] (1) Preparation of test sheets for measuring complex shear viscosity In the examples and comparative examples, each component shown in Table 1 or 2 was kneaded for 4 minutes at 200 rpm and 320°C under a nitrogen atmosphere using a small compounder (DSMXplore "Micro15 Compounder"). After kneading, the molten compounded composition was extracted in strand form and cut to a length of approximately 1 mm. The above molten and mixed composition was subjected to a vacuum hot press (IMC-1 83B, manufactured by Imoto Seisakusho Co., Ltd.) using an oil rotary pump to reduce the pressure to -0.1 MPaG, preheated at 320°C for 2 minutes, and then pressed at 70 kN (1.7 MPa) for 2 minutes. Subsequently, it was cooled at 70 kgf / cm² using a cooling press equipped with water flow cooling. 2 A 0.5 mm thick pressed sheet was produced by pressing at 6.9 MPa for 2 minutes. A test sheet was cut from the resulting pressed sheet into a cylindrical shape with a diameter of 8 mm. (2) Changes in complex shear viscosity over time Based on ISO 6721-10:1999, a distortion-controlled dynamic viscoelastic device "ARES-G2" (manufactured by T.A. Instruments Japan Co., Ltd.) with a disk diameter of 8 mm was used as a parallel plate vibrating rheometer. The above test sheet completely filled the gap between the two flat plates, and the test sheet was subjected to a strain of 0.1% at a temperature of 320°C and an angular frequency of 100 rad·s. -1 The mixture was melted and kneaded under a nitrogen atmosphere or an air atmosphere (atmosphere) while being vibrated. After the start of the melt-mixing process described above, the complex shear viscosity was measured every 8.5 seconds from 60 seconds to 1500 seconds. The logarithmic value of the complex shear viscosity decreased linearly with the measurement time. The slope of this slope was determined, and the stability of the physical properties during melt-mixing was evaluated from the absolute value of this slope. The evaluation results are shown in Table 1 or 2. A smaller slope (absolute value of the numerical value) indicates that the stability of the physical properties of the molten compound is maintained. (3) Complex shear viscosity retention The complex shear viscosity retention rate was calculated from the complex shear viscosity measured under the above conditions at 4 minutes and 15 minutes after the start of mixing. Complex shear viscosity retention rate (%) = (Complex shear viscosity 15 minutes after mixing start / Complex shear viscosity 4 minutes after mixing start) × 100 The evaluation results are shown in Table 1 or 2. A higher value for the complex shear viscosity retention rate (%) indicates that the stability of the physical properties is maintained.

[0061] [Breaking strength] In Example 1 and Comparative Example 1, each component shown in Table 1 or 2 was melt-kneaded using a small compounder (DSMXplore's "Micro15 Compounder") under a nitrogen atmosphere at 200 rpm and 320°C. For the molten and mixed compositions at 4 minutes and 15 minutes after the start of the above-mentioned molten and mixed process, small test specimens (1BA type dumbbell test specimens as described in Annex A of JIS 7161-2) were molded using a small injection molding machine ("MicroInjectionMouldingMachine 10cc" manufactured by DSMXplore) under the conditions of injection pressure of 0.3 MPa, mold holding time of 35 seconds, and mold temperature of 180°C. The prepared dumbbell test specimens were stored at 23°C and 49% humidity for more than 24 hours. The breaking strength (MPa) was measured using a universal material testing machine (INSTRON 5900R-5666, manufactured by Instron) at 23°C and 49% humidity at a tensile speed of 5 mm / min, in accordance with JIS K 7161-1:2014. Each measurement was performed five times, and the average value was used. The strength retention rate was calculated from the fracture strength of the dumbbell test specimens prepared under the conditions described above, 4 minutes and 15 minutes after the start of melting and mixing, based on the following formula. Strength retention rate (%) = (Fracture strength of dumbbell specimen prepared under conditions 15 minutes after mixing start / Fracture strength of dumbbell specimen prepared under conditions 4 minutes after mixing start) × 100 The evaluation results are summarized in Table 3. A higher percentage for strength retention indicates that the tensile properties are better preserved.

[0062] [Analysis of the amount of additives present in the molten compound] The melt-kneaded compositions obtained in Example 1 and Comparative Example 5 were injection-molded, and the molded pieces obtained were cryogenically pulverized to obtain powders. Approximately 25 g was precisely weighed from the obtained powders, and Soxhlet extraction was carried out with chloroform for 8 hours. After extraction, it was concentrated with an evaporator (40 °C) and vacuum dried (40 °C, 6 hours). Approximately 20 mg of the obtained solid was precisely weighed, made up to 10 mL with acetonitrile, and HPLC measurement was carried out to calculate the abundance of components (additives) other than the 3-methyl-1-butene-based polymer. <HPLC Analysis> Apparatus: ACQUITY UPLC H-class Column: ACQUITY UPLC BEH C18 2.1 × 100 mm, 1.7 μm (waters) Mobile phase: Solution A 0.1 mass% aqueous formic acid solution, Solution B acetonitrile / tetrahydrofuran = 1 / 1 (volume ratio) Gradient conditions (concentration of Solution B): 0 - 3 minutes... 50%, 3 - 7.1 minutes... 95%, 7.1 - 10 minutes... 50% Flow rate: 0.4 mL / min Temperature: 40 °C Detector: PDA (280 nm), ELSD Injection volume: 5 μL

[0063] [Method for Measuring Oxygen Concentration] In Examples and Comparative Examples, an oxygen concentration meter (manufactured by Shin Cosmos Electric Co., Ltd., "XP-3180E") hermetically installed in a viscoelasticity control type dynamic viscoelasticity device "ARES-G2" (manufactured by TA Instruments Japan) was used to measure the oxygen concentration in parallel with the measurement of the change over time of the complex shear viscosity described above. Also, in Examples 1 to 8 and Comparative Examples 1 to 4, 7, and 8, the oxygen concentration inside the hopper was measured with an oxygen concentration meter (manufactured by Shin Cosmos Electric Co., Ltd., "XP-3180E") hermetically installed in a hopper attached to a small kneader ("Micro15Compounder" manufactured by DSMXplore). The measurement of the oxygen concentration was started after continuously injecting nitrogen into the inside of the small kneader for at least 10 minutes. Nitrogen injection was continued during the measurement of the oxygen concentration. While continuing the nitrogen injection, then, each component shown in Table 1 or 2 was charged and melt-kneaded.

[0064] [Each ingredient] The components used in the examples and comparative examples are as follows: <3-methyl-1-butene polymer (P3MB)> • Copolymer (A): 3-methyl-1-butene copolymer produced in Production Example 1 • Copolymer (B): 3-methyl-1-butene copolymer produced in Production Example 2 • Homopolymer (C): 3-methyl-1-butene homopolymer produced in Production Example 3 <Alkyl radical scavenger> A-1: 2,4-di-t-amyl-6-[1-(3,5-di-t-amyl-2-hydroxyphenyl)ethyl]phenylacrylate, trade name "SumiLizer® GS", manufactured by Sumitomo Chemical Co., Ltd. A-2: 5,7-di-t-butyl-3-(3,4-dimethylphenyl)-3H-benzofuran-2-one, manufactured by Tokyo Chemical Industry Co., Ltd. <Phenol-based antioxidants> • B-1: Pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], trade name "AO-60", manufactured by ADEKA Corporation · B-2: 1,3,5-Tris(3,5-di-t-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, trade name "ADEKA Stab (registered trademark) AO-20", manufactured by ADEKA Corporation <Phosphorus-based antioxidants> • C-1: 3,9-bis(2,6-di-t-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, trade name "ADEKA Stab (registered trademark) PEP-36", manufactured by ADEKA Corporation. • C-2: Composition mainly composed of tetrakis(2,4-di-t-butylphenyl)-4,4'-biphenylenephosphonite, trade name "HOSTANOX® P-EPQ", manufactured by Clariant. <Sulfur-based antioxidants> • D-1: 2,2-bis{[3-(dodecylthio)-1-oxopropoxy]methyl}propane-1,3-diylbis[3-(dodecylthio)propionate], trade name "ADEKA Stab (registered trademark) AO-412S", manufactured by ADEKA Corporation. <Catechols> • E-1:4-t-butyl-pyrocatechol, manufactured by Tokyo Chemical Industry Co., Ltd. <Nitoxy radicals> • E-2: Bis(2,2,6,6-tetramethyl-4-piperidyl-1-oxyl) sebaset, manufactured by Tokyo Chemical Industry Co., Ltd. <Other additives> • Antacid: Zinc stearate

[0065] [Catalyst adjustment] Preparation of titanium catalyst components 47.6 g (500 mmol) of anhydrous magnesium chloride, 250 mL of decane, and 234 mL (1.5 mL) of 2-ethylhexyl alcohol were heated at 130°C for 2 hours to obtain a homogeneous solution. After cooling the resulting homogeneous solution to room temperature (23°C), it was added dropwise over 1 hour to 2 L (18 mol) of titanium tetrachloride, which was maintained at -20°C. After the addition was complete, the temperature of the mixture was raised to 110°C over 2 hours. At 110°C, 42.4 mL (160 mmol) of dibutyl phthalate was added, and the mixture was held at the same temperature with stirring for 2 hours. After the 2-hour reaction was complete, the mixture was allowed to stand, and the supernatant was removed. Decane and hexane were added, and the solid components were washed three times. The mixture was then resuspended in 2 L of titanium tetrachloride, and the reaction was repeated at 110°C for 2 hours. After the reaction was complete, the mixture was allowed to stand again with decane and hexane, and the supernatant was removed repeatedly until no free titanium compounds were detected in the washings. The resulting suspension was dried under reduced pressure at room temperature for 6 hours to obtain a dried titanium catalyst component. The composition of the obtained titanium catalyst component was 4.0% by mass of titanium, 56.0% by mass of chlorine, 17.0% by mass of magnesium, and 11.0% by mass of dibutyl phthalate.

[0066] [Manufacturing Example 1] Manufacturing of copolymer (A) In a 20 L stainless steel autoclave, 8.0 kg of 3-methyl-1-butene, 0.6 kg of 1-decene, 50 g of triethylaluminum diluted with hexane to a concentration of 1 mol / L, and 4 g of the titanium catalyst component prepared in [Catalyst Preparation] above were added, and the polymerization reaction was carried out at 70°C for 4 hours. During the polymerization reaction, hydrogen was continuously supplied at a rate of 40 mL / min. After 4 hours, 200 g of isoamyl alcohol was injected under pressure to stop the reaction and expel any excess unreacted monomers. Next, 2 kg of n-heptane was introduced, and after stirring at 60°C for 30 minutes, the solid components were filtered off using a pressure filter. After repeating this procedure twice, the solvent was changed from 2 kg of n-heptane to 3 kg of 2-propanol, and the same procedure was repeated twice. 7.7 kg of the obtained crude polymer was placed in a 50 L container equipped with a stirrer, and then 8 kg of 1 mol / L hydrochloric acid and 16 kg of 2-propanol were added and the mixture was stirred for 1 hour. This suspension was filtered off by vacuum filtration and washed with 10 kg of 2-propanol. The resulting washed polymer was dried under reduced pressure at 80°C for 2 days to obtain 3.2 kg of copolymer (A), which is a copolymer of 3-methyl-1-butene and 1-decene. The obtained copolymer (A) was subjected to the above-described measurements, and its melting point was found to be 296°C. Furthermore, the content of constituent units derived from the comonomer 1-decene in copolymer (A) was 1.1 mol%. The melt viscosity of the molten compound obtained in Example 1 was 104 Pa·s.

[0067] [Manufacturing Example 2] Manufacturing of copolymer (B) The same procedure as in Production Example 1 was followed, except that 0.6 kg of 1-decene was replaced with 3.6 kg of 1-decene to obtain 2.8 kg of copolymer (B), which is a copolymer of 3-methyl-1-butene and 1-decene. The melting point of the obtained copolymer (B) was found to be 281°C when the above measurements were performed. Furthermore, the content of constituent units derived from the comonomer 1-decene in copolymer (B) was 6.4 mol%. The melt viscosity of the molten compound obtained in Example 7 was 99 Pa·s.

[0068] [Manufacturing Example 3] Production of homopolymer (C) Except for the absence of 0.6 kg of 1-decene, the same procedure as in Production Example 1 was followed to obtain 3.3 kg of homopolymer (C), which is a homopolymer of 3-methyl-1-butene. The obtained homopolymer (C) was subjected to the above-described measurements, and its melting point was found to be 305°C. Furthermore, the melt viscosity of the molten compound obtained in Example 8 was 126 Pa·s.

[0069] [Example 1] Using each component shown in Table 1, the molten compound was evaluated according to the evaluation methods for [stability of physical properties in molten compounding] and [strength retention rate] described above. Furthermore, regarding the evaluation results of the above-mentioned [Analysis of the amount of additives present in the molten compound], the amount of additives present in the injection-molded piece after a mixing time of 4 minutes was 520 ppm by mass for A-1, 1,100 ppm by mass for B-1, and 490 ppm by mass for C-1. The amount of additives present in the injection-molded piece after a mixing time of 15 minutes was 170 ppm by mass for A-1, 520 ppm by mass for B-1, and 130 ppm by mass for C-1.

[0070] [Examples 2-8 and Comparative Examples 1-8] The same tests as in Example 1 were conducted and evaluated, except that the components and their proportions were changed as shown in the table. The results are shown in Table 1 or 2. Furthermore, in Comparative Example 5, regarding the evaluation results of the [Analysis of the amount of additive present in the molten-mixed composition] described above, the amount of additive present in the injection-molded piece after a mixing time of 4 minutes was 400 ppm by mass for A-1, 965 ppm by mass for B-1, and 536 ppm by mass for C-1. After a mixing time of 15 minutes, the amount of additive present in the injection-molded piece was 61 ppm by mass for A-1, 1183 ppm by mass for B-1, and 263 ppm by mass for C-1.

[0071] [Table 1]

[0072] [Table 2]

[0073] [Table 3]

[0074] <Consideration> In Comparative Example 1, despite containing a larger amount of antioxidant compared to Example 1, the absence of an alkyl radical scavenger resulted in a larger absolute value for the slope of the logarithm of the complex shear viscosity from 60 to 900 seconds, and lower viscosity and strength retention rates. This indicates that the 3-methyl-1-butene polymer deteriorated rapidly during melt mixing. Furthermore, a comparison between Example 1 and Comparative Example 1 shows that a smaller absolute value for the slope of the logarithm of the complex shear viscosity from 60 to 900 seconds indicates higher strength retention, meaning that the mechanical strength of the molded article can be maintained at a higher level. Example 2 shows that the effects of the present invention can be achieved even when the alkyl radical scavenger is a benzofuranone. Examples 1, 3, and 4 show that alkyl radical scavengers alone are effective in suppressing the degradation of 3-methyl-1-butene polymers during melt kneading, regardless of the presence or absence of antioxidants. On the other hand, Comparative Example 3 shows that there is no effect without the alkyl radical scavenger. Examples 1 and 5 show that even an amount of alkyl radical scavenger as small as 0.02 parts by mass is effective in suppressing the degradation of 3-methyl-1-butene polymers during melt kneading. From Example 6 and Comparative Example 2, it can be seen that the composition containing the antioxidant described in Patent Document 1 is insufficient in suppressing the degradation of the 3-methyl-1-butene polymer during melt mixing, although it does have some effect in suppressing the degradation of the 3-methyl-1-butene polymer during melt mixing compared to the composition without a stabilizer, and that an alkyl radical scavenger is necessary. Furthermore, from Comparative Example 4, it can be seen that the composition containing the antioxidant described in Patent Document 2 is insufficient in suppressing the degradation of the 3-methyl-1-butene polymer during melt mixing. Examples 7 and 8 demonstrate that even 3-methyl-1-butene copolymers and 3-methyl-1-butene homopolymers with high copolymerization ratios are effective in suppressing degradation during melt kneading by alkyl radical scavengers. Examples 1, Comparative Examples 1, 5, and 6 show that the inhibitory effect of alkyl radical scavengers on the degradation of 3-methyl-1-butene polymers during melt kneading is achieved by kneading under low-oxygen conditions, such as an inert atmosphere, rather than in the atmosphere. From Example 1 and Comparative Example 7, it can be seen that catechols do not have an effect in suppressing the degradation of 3-methyl-1-butene polymers during melt kneading. From Example 1 and Comparative Example 8, it can be seen that nitroxyl radicals do not have an effect in suppressing the degradation of 3-methyl-1-butene polymers during melt kneading. From Comparative Examples 7 and 8, it is considered that catechols and nitroxy radicals do not have a stabilizing function, and therefore the effects of the present invention cannot be obtained.

Claims

1. A method for producing a molten compound, comprising the step of melt-mixing a 3-methyl-1-butene polymer and an alkyl radical scavenger at 300 to 380°C in a state with a lower oxygen level than that of the atmosphere.

2. A method for producing a molten compound according to claim 1, further comprising the step of injecting an inert gas into the inside of a molten compounding machine, wherein the molten compounding is performed inside the molten compounding machine.

3. A method for producing a molten compound according to claim 1 or 2, further comprising a step of degassing the inside of a molten compounding machine under reduced pressure, wherein the molten compounding is performed inside the molten compounding machine.

4. The process involves melt-kneading a 3-methyl-1-butene polymer with an alkyl radical scavenger. The aforementioned melt mixing is carried out at 300 to 380°C, and, The melting and mixing is performed by injecting an inert gas into the melting and mixing machine, or The melting and mixing process is carried out by degassing the inside of the melting and mixing machine under reduced pressure. A method for producing a molten compound.

5. A method for producing a melt-kneaded composition according to claim 1 or 4, wherein the melt-kneading is performed for 1 to 15 minutes.

6. A method for producing a melt-kneaded composition according to claim 1 or 4, wherein the 3-methyl-1-butene polymer is at least one selected from the group consisting of a 3-methyl-1-butene homopolymer and a copolymer of 3-methyl-1-butene and an α-olefin having 2 to 20 carbon atoms.

7. A method for producing a melt-kneaded composition according to claim 6, wherein the content of structural units derived from the α-olefin in the copolymer is greater than 0 mol% and less than or equal to 20 mol%.

8. A method for producing a melt-mixed composition according to claim 1 or 4, wherein the alkyl radical scavenger comprises at least one selected from the group consisting of acrylic phenol compounds and benzofuranone compounds.

9. A method for producing the melt-mixed composition according to claim 8, wherein the acrylicphenol compound is represented by the following general formula (I). 【Chemistry 1】 (In general formula (I), R １ R represents a hydrogen atom or a methyl group. ２ R represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. ３ , R ４ , R ５ and R ６ Each of these independently represents an alkyl group having 1 to 9 carbon atoms.

10. A method for producing the melt-mixed composition according to claim 8, wherein the benzofuranone compound is represented by the following general formula (II). 【Chemistry 2】 (In general formula (II), R ７ and R ８ each independently represent an alkyl group having 1 to 4 carbon atoms, and R ９ and R １０ each independently represent an alkyl group having 1 to 9 carbon atoms.)

11. A method for producing a melt-mixed composition according to claim 1 or 4, wherein the amount of the alkyl radical scavenger blended with 100 parts by mass of the 3-methyl-1-butene polymer is 0.01 to 1.00 parts by mass.

12. In the aforementioned melting and kneading process, A method for producing a melt-mixed composition according to claim 1 or 4, further comprising adding at least one antioxidant selected from the group consisting of phenolic antioxidants and phosphorus-based antioxidants, and then performing the melt-mixing.

13. A molten compound produced by the method for producing a molten compound according to claim 1 or 4.

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