Polymer composition, method for producing a polymer composition, method for producing a solution of a crude polymer composition, and method for producing a crude polymer composition

Abstract

The present invention aims to provide a polymer composition in which the color tone of a molded article changes little, and in particular, the value of yellowness index (YI) is small, and to provide a production method of a polymer composition in which the color tone of a molded article changes little, and in particular, the value of yellowness index (YI) is small, and to provide a production method of a solution of a crude polymer composition and a production method of a crude polymer composition, which can be included as a process of the production method of a polymer composition. The present invention relates to a polymer composition containing an acid-modified polypropylene, and at least one dimethylfuran compound selected from the group consisting of 2,5-dimethylfuran, 2,4-dimethylfuran and 3,4-dimethylfuran, the total content of the dimethylfuran compound(s) being less than 15 mass ppm relative to the total mass of the polymer composition; and, the present invention relates to a production method which is a production method of the polymer composition, a solution of a crude polymer composition or a crude polymer composition, and includes specific processes in a specific order.

Description

Technical Field

[0001] This invention relates to a polymer composition, a method for manufacturing the polymer composition, a method for manufacturing a solution of a crude polymer composition, and a method for manufacturing a crude polymer composition. Background Technology

[0002] Polypropylene (the term "polypropylene" in this specification includes copolymers of propylene with other copolymerizable monomers, but excludes acid-modified polypropylene) is relatively inexpensive and possesses good moldability, heat resistance, solvent resistance, mechanical properties, and appearance, thus it is processed into various molded articles and used in many fields. However, polypropylene is essentially composed of saturated hydrocarbons, lacks chemical reactivity, and has low polarity; therefore, improvements in adhesion, coatability, and printability are desired.

[0003] As a method to improve these properties, it is known to modify polypropylene by grafting unsaturated carboxylic acids, such as maleic anhydride, or their anhydrides with polypropylene. Such acid-modified polypropylene is manufactured by grafting acid components using organic peroxides, free radicals generated by pyrolysis, etc., as initiators (Patent Document 1).

[0004] Grafting reactions for polypropylene include solution modification in organic solvents and melt modification while heating and melting. Solution modification is characterized by the ability to carry out the reaction at lower temperatures, easy and uniform grafting, and thus, easy to obtain acid-modified polypropylene with high grafting amounts.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2006-328388 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] However, polymer compositions containing acid-modified polypropylene manufactured by solution modification have the following problem: sheets produced by hot pressing exhibit a yellowness deviation (hereinafter also referred to as "YI") due to the manufacturing process. If such polymer compositions are used for molding films, sheets, bottles, etc., the hue of the molded products becomes an issue.

[0010] Therefore, the objective of this invention is to provide a polymer composition with minimal hue variation in the molded article, particularly with a low yellowness (YI) value. Furthermore, the objective of this invention is to provide a method for manufacturing a polymer composition with minimal hue variation in the molded article, particularly with a low yellowness (YI) value. Additionally, the objective of this invention is to provide a method for manufacturing a solution of a crude polymer composition and a method for manufacturing the crude polymer composition, both of which can be included as processes in the method for manufacturing the said polymer composition.

[0011] Solution for solving the problem

[0012] In view of the above, the inventors conducted extensive and in-depth research, and surprisingly discovered that, in a polymer composition containing acid-modified polypropylene and at least one dimethylfuran compound selected from the group consisting of 2,5-dimethylfuran, 2,4-dimethylfuran, and 3,4-dimethylfuran, by making the total content of the dimethylfuran compound relative to the total mass of the polymer composition less than a specific value, a polymer composition with less hue variation, particularly a low yellowness (YI) value, can be obtained, thus completing the present invention. Furthermore, it was discovered that by employing a manufacturing method that includes specific steps in a specific sequence, a polymer composition with less hue variation, particularly a low yellowness (YI) value, can be manufactured, thus completing the present invention.

[0013] That is, the present invention is based on the following principles.

[0014] Embodiment 1 of the present invention relates to a polymer composition.

[0015] It contains acid-modified polypropylene and at least one dimethylfuran compound selected from the group consisting of 2,5-dimethylfuran, 2,4-dimethylfuran, and 3,4-dimethylfuran.

[0016] The total content of the dimethylfuran compound relative to the total mass of the polymer composition is less than 15 ppm by mass.

[0017] Embodiment 2 of the present invention relates to a polymer composition, in which, in the polymer composition of Embodiment 1,

[0018] The total content of the dimethylfuran compound relative to the total mass of the polymer composition is 0.5 ppm by mass or more.

[0019] Embodiment 3 of the present invention relates to a polymer composition, in which the polymer composition of Embodiment 1 or 2,

[0020] The total content of the dimethylfuran compound relative to the total mass of the polymer composition is 1 ppm or more.

[0021] Embodiment 4 of the present invention relates to a polymer composition, wherein in any one of embodiments 1 to 3,

[0022] The total content of the dimethylfuran compound relative to the total mass of the polymer composition is less than 12 ppm by mass.

[0023] Embodiment 5 of the present invention relates to a polymer composition, wherein in any one of embodiments 1 to 4,

[0024] According to JIS K 7210: the melt flow rate measured in 2014 at 180℃ and a load of 21.2N was 150–2000 g / 10 min.

[0025] Embodiment 6 of the present invention relates to a polymer composition, wherein in the polymer composition of any one of embodiments 1 to 5,

[0026] The grafting rate of the acid-modified polypropylene is 1.0 to 20% by mass.

[0027] Embodiment 7 of the present invention relates to a food packaging material comprising a polymer composition of any one of embodiments 1 to 6.

[0028] Embodiment 8 of the present invention relates to a medical product comprising a polymer composition of any one of embodiments 1 to 6.

[0029] Embodiment 9 of the present invention relates to an automotive component comprising a polymer composition of any one of embodiments 1 to 6.

[0030] Embodiment 10 of the present invention relates to a battery component comprising a polymer composition of any one of embodiments 1 to 6.

[0031] Embodiment 11 of the present invention relates to the use of a polymer composition in food packaging materials, said polymer composition being any one of embodiments 1 to 6.

[0032] Embodiment 12 of the present invention relates to the use of a polymer composition in a medical product, said polymer composition being any one of embodiments 1 to 6.

[0033] Embodiment 13 of the present invention relates to the use of a polymer composition in an automotive component, said polymer composition being any one of embodiments 1 to 6.

[0034] Embodiment 14 of the present invention relates to the use of a polymer composition in a battery component, said polymer composition being any one of embodiments 1 to 6.

[0035] Embodiment 15 of the present invention relates to a method for manufacturing a polymer composition.

[0036] The polymer composition is a polymer composition of any one of methods 1 to 6.

[0037] The manufacturing method includes the following steps 1A to 5A in sequence.

[0038] (Process 1A)

[0039] In a reaction solvent comprising aromatic hydrocarbon solvents and at least one selected from the group consisting of acetone and its derivatives,

[0040] The process involves heating and dissolving polypropylene and at least one acid component selected from the group consisting of unsaturated carboxylic acids and their derivatives to obtain a solution 1A containing the polypropylene and the acid component.

[0041] (Process 2A)

[0042] The process involves adding an organic peroxide to the solution 1A to obtain a solution 2A containing acid-modified polypropylene.

[0043] (Process 3A)

[0044] The process of separating the solution 2A into a polymer composition and a filtrate to obtain the polymer composition.

[0045] (Process 4A)

[0046] The process involves purifying the filtrate to obtain a treatment solvent.

[0047] (Process 5A)

[0048] A process in which the processing solvent is reused as part or all of the reaction solvent in step 1A.

[0049] Embodiment 16 of the present invention relates to a manufacturing method, in which the manufacturing method of Embodiment 15,

[0050] The step 3A includes the step of separating the solution 2A into the polymer composition and the filtrate by crystallization purification.

[0051] Embodiment 17 of the present invention relates to a manufacturing method, in which the manufacturing methods of Embodiments 15 or 16,

[0052] The purification process in step 4A includes distillation purification.

[0053] Embodiment 18 of the present invention relates to a manufacturing method, wherein in the manufacturing method of any one of embodiments 15 to 17,

[0054] The total content of at least one of the group consisting of acetone and its derivatives is less than 0.2% by mass relative to the total mass of the processing solvent.

[0055] Embodiment 19 of the present invention relates to a method for manufacturing a polymer composition.

[0056] The polymer composition is a polymer composition of any one of methods 1 to 6.

[0057] The manufacturing method includes the following steps 1B to 4B in sequence.

[0058] (Process 1B)

[0059] In a reaction solvent comprising aromatic hydrocarbon solvents and at least one selected from the group consisting of acetone and its derivatives,

[0060] The process involves heating and dissolving polypropylene and at least one acid component selected from the group consisting of unsaturated carboxylic acids and their derivatives to obtain a solution 1B containing the polypropylene and the acid component.

[0061] (Process 2B)

[0062] The process involves adding an organic peroxide to the solution 1B to obtain a solution 2B containing acid-modified polypropylene.

[0063] (Process 3B)

[0064] The process of separating the solution 2B into a polymer composition and a filtrate by crystallization purification to obtain the polymer composition.

[0065] (Process 4B)

[0066] The process of purifying the filtrate by distillation.

[0067] Embodiment 20 of the present invention relates to a method for manufacturing a solution of a crude polymer composition.

[0068] The solution of the crude polymer composition contains acid-modified polypropylene and at least one dimethylfuran compound selected from the group consisting of 2,5-dimethylfuran, 2,4-dimethylfuran, and 3,4-dimethylfuran.

[0069] The manufacturing method includes the following steps 1C to 2C in sequence.

[0070] (Process 1C)

[0071] In a reaction solvent comprising aromatic hydrocarbon solvents and at least one selected from the group consisting of acetone and its derivatives,

[0072] The process involves heating and dissolving polypropylene and at least one acid component selected from the group consisting of unsaturated carboxylic acids and their derivatives to obtain a solution 1C containing said polypropylene and said acid component.

[0073] (Process 2C)

[0074] The step of adding an organic peroxide to the solution 1C to obtain a solution 2C containing a crude polymer composition of acid-modified polypropylene.

[0075] Embodiment 21 of the present invention relates to a method for manufacturing a crude polymer composition.

[0076] The crude polymer composition contains acid-modified polypropylene and at least one dimethylfuran compound selected from the group consisting of 2,5-dimethylfuran, 2,4-dimethylfuran, and 3,4-dimethylfuran.

[0077] The manufacturing method includes the following steps 1D to 3D in sequence.

[0078] (Process 1D)

[0079] In a reaction solvent comprising aromatic hydrocarbon solvents and at least one selected from the group consisting of acetone and its derivatives,

[0080] The process involves heating and dissolving polypropylene and at least one acid component selected from the group consisting of unsaturated carboxylic acids and their derivatives to obtain a solution 1D containing said polypropylene and said acid component.

[0081] (Process 2D)

[0082] The process involves adding an organic peroxide to the solution 1D to obtain a solution 2D containing acid-modified polypropylene.

[0083] (Process 3D)

[0084] The process of separating the solution into a crude polymer composition and a filtrate to obtain the crude polymer composition.

[0085] Embodiment 22 of the present invention relates to a manufacturing method, in which, in the manufacturing method of embodiment 21,

[0086] The sequence following process 3D includes processes 4D through 5D.

[0087] (Process 4D)

[0088] The process involves purifying the filtrate to obtain a treatment solvent.

[0089] (Process 5D)

[0090] A process in which the processing solvent is reused as part or all of the reaction solvent in step 1D.

[0091] Embodiment 23 of the present invention relates to a manufacturing method, in which the manufacturing methods of Embodiments 21 or 22,

[0092] The process 3D includes the step of separating the solution 2D into the crude polymer composition and the filtrate through crystallization purification.

[0093] Embodiment 24 of the present invention relates to a manufacturing method, in which the manufacturing method of Embodiment 22,

[0094] The purification process in step 4D includes distillation purification.

[0095] Embodiment 25 of the present invention relates to a manufacturing method, in which the manufacturing methods of Embodiments 22 or 24,

[0096] The total content of at least one of the group consisting of acetone and its derivatives is less than 0.2% by mass relative to the total mass of the processing solvent.

[0097] Embodiment 26 of the present invention relates to a manufacturing method, wherein in any one of embodiments 21 to 25,

[0098] The total content of the dimethylfuran compound relative to the total mass of the crude polymer composition is less than 15 ppm by mass.

[0099] Invention Effects

[0100] According to the present invention, a polymer composition with minimal hue variation in the molded article, particularly a low yellowness (YI) value, can be provided. Furthermore, according to the present invention, a method for manufacturing a polymer composition with minimal hue variation in the molded article, particularly a low yellowness (YI) value, can be provided. Moreover, according to the present invention, a method for manufacturing a solution of a crude polymer composition and a method for manufacturing the crude polymer composition, both of which can be included as processes in the method for manufacturing the said polymer composition, can be provided. Detailed Implementation

[0101] The embodiments of the present invention will now be described in detail, but these embodiments are merely examples of embodiments of the present invention, and the present invention is not limited thereto. The present invention can be implemented in any way without departing from the spirit of the present invention.

[0102] In this specification, when using "~" followed by numerical values ​​or property values, the meaning is to include both the values ​​before and after it. Furthermore, regarding the numerical ranges described in stages in this specification, the upper or lower limit of a numerical range for a particular stage can be arbitrarily combined with the upper or lower limits of numerical ranges for other stages. Additionally, the upper or lower limit of the numerical range described in this specification can be replaced with the values ​​shown in the embodiments.

[0103] <Polymer Composition>

[0104] The polymer composition of the present invention is a polymer composition containing acid-modified polypropylene and at least one dimethylfuran compound selected from the group consisting of 2,5-dimethylfuran, 2,4-dimethylfuran and 3,4-dimethylfuran, wherein the total content of the dimethylfuran compound relative to the total mass of the polymer composition is less than 15 ppm by mass.

[0105] It should be noted that, in this specification, the total content of dimethylfuran compounds refers to the content of that single compound when the dimethylfuran compound consists of only one type. Furthermore, when the dimethylfuran compound consists of two or more types, it refers to the total content of each compound.

[0106] The following details the components that may be contained in the polymer composition.

[0107] [Acid-modified polypropylene]

[0108] The polymer compositions of embodiments of the present invention contain acid-modified polypropylene. Acid-modified polypropylene is formed by grafting an acid component onto polypropylene. Preferably, the polymer compositions of embodiments of the present invention consist of acid-modified polypropylene.

[0109] In one embodiment, acid-modified polypropylene can be obtained by the method for manufacturing polymer compositions described later, in a manner that incorporates it into the polymer composition.

[0110] (Grafting rate)

[0111] Grafting rate refers to the percentage of unsaturated carboxylic acids and / or their derivatives in acid-modified polypropylene, which has been pre-quantified using nuclear magnetic resonance (NMR) as a standard sample. This content is then measured using a standard curve plotted based on the quantified values ​​and an infrared spectroscopy device. For example, it can be determined by measuring the specific absorption of carboxylic acids and / or their derivatives in samples compressed into sheets approximately 100 μm thick, specifically at 1900–1600 cm⁻¹. -1 The carbonyl characteristic absorption of (C=O stretching vibration band) is used to determine the result.

[0112] It should be noted that acid-modified polypropylene sometimes contains unreacted unsaturated carboxylic acids and / or their derivatives that were not used in the reaction or reacted with the raw polypropylene. As a pretreatment for such residues, the compressed sample is placed in a Soxhlet extractor, refluxed with acetone at 80°C for 1 hour, and then dried at 80°C for 2 hours. The dried sheet is then used as a sample for analysis, thereby determining the amount of unsaturated carboxylic acids and / or their derivatives grafted onto the polypropylene in the test sample.

[0113] In the examples described later, the residual unsaturated carboxylic acids and / or their derivatives in the acid-modified polypropylene were less than 0.01% by mass, which was negligible, and therefore the above-described pretreatment was not performed.

[0114] If the grafting rate is 1.0% by mass or more, a large number of polar groups such as carboxylic acid groups contained in the acid component can be introduced into the polymer, which can improve the adhesion to polar polymers, and is therefore preferred. In addition, if the grafting rate is 20% by mass or less, the decrease in molecular weight during acid modification can be suppressed, and at the same time, the physical properties of adhesive strength and impact resistance can be ensured, and is therefore preferred.

[0115] In the polymer compositions of embodiments of the present invention, for example, the grafting rate of acid-modified polypropylene can be 1.0 to 20% by mass.

[0116] (Melting point)

[0117] There are no particular limitations on the melting point of acid-modified polypropylene, but it is preferably above 90°C, and more preferably above 120°C. If the melting point is above 90°C, it can be sterilized by boiling; if the melting point is above 120°C, it can be used for retort packaging. It should be noted that the melting point can be determined using a differential scanning calorimeter (DSC), typically with the heating and cooling rates set to 10°C / minute. However, the melting point is usually below 200°C.

[0118] The amount of acid-modified polypropylene that dissolves in n-heptane (25°C, 60 minutes) as determined by the dissolution test according to the Japanese Food Sanitation Law is not particularly limited, but is preferably 150 ppm by mass or less, more preferably 30 ppm by mass or less. If it has high oil resistance, it can be used as a packaging material for oily foods and other highly oily substances, and is therefore preferred.

[0119] [Dimethylfuran compounds]

[0120] Dimethylfuran compounds are compounds selected from the group consisting of 2,5-dimethylfuran, 2,4-dimethylfuran, and 3,4-dimethylfuran.

[0121] The polymer composition of embodiments of the present invention contains a dimethylfuran compound. The dimethylfuran compound is generated from at least one source selected from the group consisting of acetone and its derivatives contained in the reaction solvent used in the manufacturing method described later. It is considered that the dimethylfuran compound is generated from at least one starting material selected from the group consisting of acetone and its derivatives contained in the reaction solvent, through a certain reaction.

[0122] The total content of dimethylfuran compounds relative to the total mass of the polymer composition is less than 15 ppm by mass, preferably 12 ppm by mass or less, and more preferably 11 ppm by mass or less. When the total content of dimethylfuran compounds relative to the total mass of the polymer composition is 15 ppm by mass or more, the hue change of the molded polymer composition, especially the value of yellowness (YI), becomes greater.

[0123] On the other hand, there is no particular limitation on the lower limit of the total content of dimethylfuran compounds relative to the total mass of the polymer composition; for example, it can be set to 0.5 ppm or more, 0.7 ppm or more, or 1 ppm or more.

[0124] Methods for reducing the total content of dimethylfuran compounds relative to the total mass of the polymer composition to less than 15 ppm by mass include, for example, distilling the reaction solvent used in the manufacture of acid-modified polypropylene to remove acetone and its derivatives; repeatedly performing the crystallization purification described later; and so on.

[0125] [Other ingredients]

[0126] (additive)

[0127] The polymer compositions of embodiments of the present invention may contain various additives as other components. Examples of such additives include polymer stabilizers such as antioxidants, metallic soaps, and hydrotalcite.

[0128] Regarding the content of additives, it is preferably 1% by mass or less relative to the total mass of the polymer composition, more preferably 0.7% by mass or less, and even more preferably 0.5% by mass or less.

[0129] [Characteristics of the polymer composition]

[0130] (YI)

[0131] The lower the YI of the polymer composition in the embodiments of the present invention, the more preferred it is, for example, preferably 40 or less, more preferably 35 or less, and even more preferably 30 or less. By keeping the YI of the polymer composition within the above range, even when used for molding films, sheets, bottles, etc., the problem of hue in the molded product is less likely to occur, and therefore it is preferred.

[0132] On the other hand, there is no particular limitation on the lower limit of YI of the polymer composition; for example, it can be set to 1 or more, 2 or more, or 3 or more.

[0133] For example, the obtained polymer composition can be processed into sheets, and the resulting sheet samples can be measured using a colorimeter.

[0134] (Mel flow rate)

[0135] In the polymer compositions of embodiments of the present invention, the melt flow rate (hereinafter also referred to as "MFR") measured according to JIS K 7210:2014 at 180°C and a load of 21.2 N is not particularly limited, but is preferably 150 g / 10 min or more, more preferably 170 g / 10 min or more, and even more preferably 200 g / 10 min or more. Furthermore, it is preferably 2000 g / 10 min or less, more preferably 1800 g / 10 min or less, and even more preferably 1500 g / 10 min or less.

[0136] If the melt flow rate is 150 g / 10 min or higher, the polymer composition containing acid-modified polypropylene exhibits good dispersibility in other polymers such as polypropylene, and is therefore preferred. Furthermore, if the melt flow rate is 2000 g / 10 min or lower, the reduction in the mechanical strength of the acid-modified polypropylene can be suppressed, and is therefore preferred.

[0137] The polymer composition of the embodiments of the present invention, for example, has a melt flow rate of 150 to 2000 g / 10 minutes, as measured according to JIS K 7210:2014 at 180°C and a load of 21.2 N.

[0138] [Uses of the polymer composition]

[0139] The polymer compositions of the embodiments of the present invention have minimal hue variation in the molded articles, particularly a low yellowness (YI) value. Therefore, they are suitable for, for example, food packaging materials such as films and trays for food packaging; medical packaging materials such as infusion bags, nutritional food / liquid food bags, and ostomy bags; medical device components that combine injection-molded parts such as drip tubes and syringes with metal needles; fluid delivery devices such as bottles and tubes used in medical applications; medical supplies such as medicine containers such as medicine tubes and medicine bottles; automotive components such as fuel tanks, fuel lines, automotive coolant lines, especially electric vehicle coolant lines; and battery components such as outer casing films and tab lead films for secondary batteries in the fields of electronics, automobiles, and robotics.

[0140] The polymer compositions of the embodiments of the present invention are particularly suitable for use in automotive components, especially in applications requiring high cooling efficiency in limited space, such as coolant pipes for electric vehicles. In electric vehicles, there is a trend towards larger batteries to achieve higher output and extended driving range; however, to maintain the interior volume (interior space), a cooling system with efficiently configured coolant pipes within a more limited space is required. The polymer compositions of the embodiments of the present invention, due to their excellent adhesive properties, are also suitable for applications such as coolant pipes for electric vehicles.

[0141] That is, as preferred examples of embodiments of the present invention, food packaging materials, medical products, automotive parts, and battery components comprising the above-described polymer composition can be listed. Furthermore, as preferred examples of embodiments of the present invention, uses of the above-described polymer composition in food packaging materials, in medical products, in automotive parts, and in battery components can be listed.

[0142] <Method for manufacturing polymer compositions>

[0143] The manufacturing method of the polymer composition according to the embodiments of the present invention includes the following steps 1A to 5A (hereinafter also referred to as "manufacturing method A").

[0144] (Process 1A)

[0145] In a reaction solvent comprising aromatic hydrocarbon solvents and at least one selected from the group consisting of acetone and its derivatives,

[0146] The process involves heating and dissolving polypropylene and at least one acid component selected from the group consisting of unsaturated carboxylic acids and their derivatives to obtain a solution 1A containing the polypropylene and the acid component.

[0147] (Process 2A)

[0148] The process involves adding an organic peroxide to the solution 1A to obtain a solution 2A containing acid-modified polypropylene.

[0149] (Process 3A)

[0150] The process of separating the solution 2A into a polymer composition and a filtrate to obtain the polymer composition.

[0151] (Process 4A)

[0152] The process involves purifying the filtrate to obtain a treatment solvent.

[0153] (Process 5A)

[0154] A process in which the processing solvent is reused as part or all of the reaction solvent in step 1A.

[0155] Another embodiment of the present invention provides a method for manufacturing a polymer composition comprising, in sequence, the following steps 1B to 4B (hereinafter also referred to as "manufacturing method B").

[0156] (Process 1B)

[0157] In a reaction solvent comprising aromatic hydrocarbon solvents and at least one selected from the group consisting of acetone and its derivatives,

[0158] The process involves heating and dissolving polypropylene and at least one acid component selected from the group consisting of unsaturated carboxylic acids and their derivatives to obtain a solution 1B containing polypropylene and an acid component.

[0159] (Process 2B)

[0160] The process involves adding an organic peroxide to the solution 1B to obtain a solution 2B containing acid-modified polypropylene.

[0161] (Process 3B)

[0162] The process of separating the solution 2B into a polymer composition and a filtrate by crystallization purification to obtain the polymer composition.

[0163] (Process 4B)

[0164] The process of purifying the filtrate by distillation.

[0165] The preferred range of polymer compositions in the manufacturing methods of the polymer compositions of the embodiments of the present invention and the manufacturing methods of the polymer compositions of another embodiment of the present invention is the same as the range described in the above <Polymer Compositions>.

[0166] [Manufacturing Method A: Process 1A]

[0167] Step 1A in manufacturing method A involves heating and dissolving polypropylene and at least one acid component selected from the group consisting of an aromatic hydrocarbon solvent and at least one of the group consisting of acetone and its derivatives in a reaction solvent to obtain a solution 1A containing the polypropylene and the acid component.

[0168] (Components in process 1A)

[0169] The following details the components of polypropylene, acid, aromatic hydrocarbon solvent, and reaction solvent in step 1A of manufacturing method A.

[0170] Polypropylene

[0171] In one embodiment, various known propylene-based polymers can be used as polypropylene, without particular limitation. Examples include propylene homopolymers, copolymers of ethylene and propylene, copolymers of propylene with other comonomers such as butene-1, pentene-1, hexene-1, heptene-1, octene-1, cyclopentene, cyclohexene, and norbornene—α-olefin comonomers with 2 or more carbon atoms, or copolymers of two or more of these comonomers. As the α-olefin comonomer, α-olefin comonomers with 2 to 6 carbon atoms are preferred. It can be a random copolymer or a block copolymer. Furthermore, polypropylene can also be a mixture of these.

[0172] When the polypropylene is a copolymer or mixture, it is preferable to contain at least 30% by mass of polypropylene, more preferably at least 50% by mass of polypropylene, and even more preferably at least 70% by mass of polypropylene.

[0173] However, propylene homopolymers are the most preferred. The higher the propylene content in the monomers constituting polypropylene, the higher the heat resistance; furthermore, there is a tendency to increase the adhesion of polypropylene. Consequently, it is less prone to gelation, suppressing defects such as so-called fisheyes.

[0174] As for polypropylene, isotactic polypropylene is preferred. Compared with other stereoregular polypropylenes such as atactic and syndiotactic polypropylene, isotactic polypropylene has higher crystallinity and excellent rigidity, heat resistance, and oil resistance, thus it is preferred. Due to its excellent rigidity, even thin-walled laminates can maintain strength, making it a preferred choice for containers formed from laminated sheets. Furthermore, due to its excellent heat resistance, it can be molded at high temperatures, and in the case of food and medical applications, it can be heat-sterilized, which is advantageous in terms of hygiene. Moreover, even higher heat resistance is required when used for retort pouches.

[0175] In addition, isotactic polypropylene is a general-purpose material and therefore inexpensive, making it a preferred choice as it can supply low-cost products.

[0176] The molecular weight of polypropylene is not particularly limited as long as it does not significantly deviate from the purpose of this invention. However, since there is a tendency for the molecular weight to decrease due to the β-cleavage reaction during the grafting reaction, a higher molecular weight is preferred. The molecular weight ratio (MFR) measured according to JIS K 7210:2014 at 230°C and 21.2N is preferably 0.01 g / 10 min or more. More preferably, the MFR is 0.1 g / 10 min or more.

[0177] Furthermore, the MFR is preferably 30g / 10 minutes or less, more preferably 20g / 10 minutes or less. Polypropylene can be used alone or in combination with two or more types.

[0178] • Acid components

[0179] In one embodiment, the acid component is at least one selected from the group consisting of unsaturated carboxylic acids and their derivatives. The acid component is not particularly limited as long as it does not significantly depart from the purpose of the invention, but is preferably an unsaturated carboxylic acid or its derivative having two or more carboxyl groups. Specifically, examples of acid components include unsaturated carboxylic acids such as maleic acid, fumaric acid, succinic acid, citraconic acid, itaconic acid, aconitic acid, and crotonic acid; and carboxylic anhydrides such as maleic anhydride, itaconic anhydride, and citraconic anhydride. Maleic acid and maleic anhydride are preferred, and maleic anhydride is particularly preferred. One acid component may be used alone, or two or more may be used in combination.

[0180] There is no particular limitation on the amount of acid component used, but it is preferably 5 parts by mass or more, more preferably 7 parts by mass or more, and even more preferably 10 parts by mass or more, relative to 100 parts by mass of polypropylene. Furthermore, it is preferably 40 parts by mass or less, more preferably 35 parts by mass or less, and even more preferably 30 parts by mass or less.

[0181] • Aromatic hydrocarbon solvents

[0182] There are no particular limitations on aromatic hydrocarbon solvents; examples include aromatic hydrocarbons such as benzene, toluene, xylene, and tert-butylbenzene; and halogenated aromatic hydrocarbons such as monochlorobenzene and o-dichlorobenzene. Among these, toluene, xylene, tert-butylbenzene, and monochlorobenzene are preferred. An aromatic hydrocarbon solvent can be used alone or in combination of two or more.

[0183] There is no particular limitation on the amount of aromatic hydrocarbon solvent used, but it is preferably 300 parts by weight or more, more preferably 350 parts by weight or more, and even more preferably 400 parts by weight or more, relative to 100 parts by weight of polypropylene. In addition, it is preferably 1,500 parts by weight or less, more preferably 1,200 parts by weight or less, and even more preferably 1,000 parts by weight or less.

[0184] • Reaction solvent

[0185] The reaction solvent includes aromatic hydrocarbon solvents and at least one selected from the group consisting of acetone and its derivatives. At least one of the group consisting of acetone and its derivatives in the reaction solvent may be incorporated, for example, in the following steps: a step of separating solution 2A into a polymer composition and a filtrate to obtain the polymer composition (step 3A); a step of reusing the treatment solvent as part or all of the reaction solvent in step 1A (step 5A); a step of separating solution 2B into a polymer composition and a filtrate by crystallization purification to obtain the polymer composition (step 3B); and so on.

[0186] The total content of at least one of the group consisting of acetone and its derivatives in the reaction solvent is not particularly limited, but is preferably 1,500 ppm by mass or less, more preferably 1,300 ppm by mass or less, and even more preferably 1,000 ppm by mass or less.

[0187] On the other hand, there is no particular limitation on the lower limit of the total content of at least one of the group consisting of acetone and its derivatives in the reaction solvent, for example, it can be set to 30 ppm or more by mass, 40 ppm or more by mass, or 50 ppm or more by mass.

[0188] Here, acetone derivatives refer to general compounds generated from acetone as a starting material. Examples of such compounds include isopropylidene acetone and 2,5-hexanedione.

[0189] (Heating to dissolve)

[0190] Heating and dissolving refers to the process of dissolving polypropylene and the acid component in a heated reaction solvent. Regarding the atmosphere during heating and dissolving, it is preferable to carry out step 2A under an inert gas atmosphere such as nitrogen. In step 2A, the heating temperature is preferably within the boiling point range of the reaction solvent, specifically, preferably 80°C to 180°C. There are no particular restrictions on the order in which the polypropylene, acid component, and reaction solvent are added; however, in manufacturing, it is preferable to add the polypropylene and acid component after adding the reaction solvent.

[0191] [Manufacturing Method A: Step 2A]

[0192] Step 2A in manufacturing method A is a step in which an organic peroxide is added to the solution 1A to obtain a solution 2A containing acid-modified polypropylene.

[0193] (Components in process 2A)

[0194] The organic peroxide, which is a component in step 2A of manufacturing method A, will be described in detail below.

[0195] Organic peroxides

[0196] Organic peroxides are not particularly limited, but examples include dialkyl peroxides such as dicumyl peroxide and 2,5-dimethyl-2,5-di(tert-butylperoxide)hexane; peroxide ketals such as 1,1-di(tert-butylperoxide)cyclohexane and 1,1-di(tert-hexylperoxide)cyclohexane; and peroxide esters such as tert-butylperoxide isopropyl monocarbonate, tert-hexylperoxide isopropyl monocarbonate, and tert-hexylperoxide 2-ethylhexyl monocarbonate. Since the grafting reaction rate is higher than the β-crack rate, dicumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxide)hexane, 1,1-di(tert-butylperoxide)cyclohexane, and tert-butylperoxide isopropyl monocarbonate are preferred, and even more preferred are dicumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxide)hexane, and tert-butylperoxide isopropyl monocarbonate.

[0197] (Reaction conditions)

[0198] The reaction conditions after adding the organic peroxide are not particularly limited. In one embodiment, the reaction temperature can be set in the range of 20°C to 160°C. Furthermore, the reaction time can be set in the range of 1 hour to 15 hours. Thus, solution 2A can be obtained.

[0199] [Manufacturing Method A: Process 3A]

[0200] Step 3A in manufacturing method A is the step of separating the solution 2A into a polymer composition and a filtrate to obtain the polymer composition.

[0201] (Components in process 3A)

[0202] The following details the filtrate, a component of step 3A in manufacturing method A.

[0203] ·filtrate

[0204] The filtrate is the liquid remaining after the polymer composition has been separated from solution 2A. The filtrate contains an aromatic hydrocarbon solvent and at least one component selected from the group consisting of acetone and its derivatives.

[0205] The total content of at least one component selected from the group consisting of acetone and its derivatives relative to the total mass of the filtrate is preferably 10 to 85% by mass, more preferably 15 to 75% by mass, and even more preferably 20 to 65% by mass. If the content is 10% by mass or more, the amount of acid-modified polypropylene precipitated can be increased, and therefore it is preferred. If it is 85% by mass or less, the efficiency of purification for removing components containing at least one component selected from the group consisting of acetone and its derivatives and / or obtaining a treatment solvent from the filtrate is improved, and therefore it is preferred.

[0206] (Method for separating polymer composition from solution 2A)

[0207] There are no particular limitations on the method for separating the polymer composition from the solution 2A; for example, methods including crystallization purification can be included. That is, step 3A may include the step of separating the solution 2A into the polymer composition and the filtrate by crystallization purification.

[0208] In crystallization purification, solvents added to precipitate acid-modified polypropylene include ketones such as acetone and methyl ethyl ketone; esters such as methyl acetate and ethyl acetate; and alcohols such as methanol and ethanol. Among these, acetone and methyl ethyl ketone are preferred from the viewpoint of ease of separation from aromatic hydrocarbon solvents and suppression of side reactions, with acetone being even more preferred.

[0209] To remove residual aromatic hydrocarbon solvents, the acid-modified polypropylene precipitated through crystallization purification can be further washed with the same solvent added during the purification process.

[0210] [Manufacturing Method A: Process 4A]

[0211] Step 4A in manufacturing method A is a step of purifying the filtrate to obtain a treatment solvent.

[0212] (Components in process 4A)

[0213] The following details the processing solvent used in step 4A of manufacturing method A.

[0214] • Solvent handling

[0215] The processing solvent is obtained by purifying the filtrate. The processing solvent contains an aromatic hydrocarbon solvent and at least one component selected from the group consisting of acetone and its derivatives.

[0216] The total content of at least one of the group consisting of acetone and its derivatives is lower than the content in the filtrate relative to the total mass of the treatment solvent.

[0217] The total content of at least one of the groups selected from acetone and its derivatives relative to the total mass of the treatment solvent is preferably 0.2% by mass or less, more preferably 0.15% by mass or less, and even more preferably 0.1% by mass or less. The lower the content, the better, and there is no particular limitation on the lower limit, for example, it can be set to 0.001% by mass or more, 0.005% by mass or more, or 0.01% by mass or more.

[0218] (Methods for obtaining processing solvents)

[0219] The treatment solvent is obtained by purifying the filtrate. The purification method is not particularly limited, but preferably includes distillation purification and purification including water extraction to remove water-soluble components. From the viewpoint of reducing the content of at least one of the group consisting of acetone and its derivatives relative to the total mass of the treatment solvent, the purification process in step 4A preferably includes distillation purification.

[0220] Distillation purification can be exemplified by simple distillation that utilizes the boiling point difference of the components contained in the filtrate, and by precision distillation that improves separation efficiency by filling the distillation column with packing material. From the viewpoint of separating at least one of the group consisting of acetone and its derivatives, precision distillation is preferred.

[0221] [Manufacturing Method A: Process 5A]

[0222] Step 5A in manufacturing method A is a step in which the processing solvent obtained in step 4A is reused as part or all of the reaction solvent in step 1A.

[0223] There are no particular restrictions on the method of reusing the processing solvent obtained in step 4A as the reaction solvent in step 1A. For example, the processing solvent can be used as the reaction solvent alone, or it can be used by blending the processing solvent with an aromatic hydrocarbon solvent (a new product that is not a reused product).

[0224] [Manufacturing Method B: Process 1B]

[0225] Step 1B in manufacturing method B involves heating and dissolving polypropylene and at least one acid component selected from the group consisting of an aromatic hydrocarbon solvent and at least one of the group consisting of acetone and its derivatives in a reaction solvent to obtain a solution 1B containing polypropylene and the acid component.

[0226] (Components in process 1B)

[0227] The aromatic hydrocarbon solvent, polypropylene, and acid components in step 1B of manufacturing method B are the same as those in step 1A of manufacturing method A.

[0228] (Heating to dissolve)

[0229] The conditions for heating and melting can be the same as those described for step 1A of manufacturing method A.

[0230] [Manufacturing Method B: Process 2B]

[0231] Step 2B in manufacturing method B is a step in which an organic peroxide is added to the solution 1B to obtain a solution 2B containing acid-modified polypropylene.

[0232] (Components in process 2B)

[0233] The organic peroxide used as a component in step 2B of manufacturing method B is the same as the organic peroxide used in step 2A of manufacturing method A.

[0234] (Reaction conditions)

[0235] The reaction conditions after adding the organic peroxide can be the same as those described for step 2A of manufacturing method A. Thus, solution 2B can be obtained.

[0236] [Manufacturing Method B: Process 3B]

[0237] Step 3B in manufacturing method B is a step of separating the solution 2B into a polymer composition and a filtrate through crystallization purification to obtain the polymer composition.

[0238] Crystallization purification can be performed using the same crystallization purification method as described in step 3A of manufacturing method A. This allows the acquisition of a polymer composition.

[0239] [Manufacturing Method B: Process 4B]

[0240] Step 4B in manufacturing method B is the step of purifying the filtrate by distillation.

[0241] Distillation purification can be performed using the same distillation purification method as described in step 4A of manufacturing method A.

[0242] [Other processes]

[0243] Manufacturing methods A and B may include any additional steps besides those described above. Examples of such steps include: nitrogen bubbling of the reaction solution before the addition of the organic peroxide, extraction of the reaction solution using water, decolorization of the reaction solution, drying of the acid-modified polypropylene, and pulverization of the acid-modified polypropylene.

[0244] <Method for preparing the solution of the crude polymer composition>

[0245] The method for manufacturing a solution of a crude polymer composition according to an embodiment of the present invention is a method for manufacturing a solution of a crude polymer composition containing acid-modified polypropylene and at least one dimethylfuran compound selected from the group consisting of 2,5-dimethylfuran, 2,4-dimethylfuran and 3,4-dimethylfuran, which sequentially includes the following steps 1C to 2C (hereinafter also referred to as "manufacturing method C").

[0246] (Process 1C)

[0247] In a reaction solvent comprising aromatic hydrocarbon solvents and at least one selected from the group consisting of acetone and its derivatives,

[0248] The process involves heating and dissolving polypropylene and at least one acid component selected from the group consisting of unsaturated carboxylic acids and their derivatives to obtain a solution 1C containing said polypropylene and said acid component.

[0249] (Process 2C)

[0250] The step of adding an organic peroxide to the solution 1C to obtain a solution 2C containing a crude polymer composition of acid-modified polypropylene.

[0251] The method for producing the solution of the crude polymer composition according to embodiments of the present invention can be included as a process for producing the polymer composition.

[0252] [Manufacturing method C: Step 1C]

[0253] Step 1C in manufacturing method C involves heating and dissolving polypropylene and at least one acid component selected from the group consisting of an aromatic hydrocarbon solvent and at least one of the group consisting of acetone and its derivatives in a reaction solvent to obtain a solution 1C containing said polypropylene and said acid component.

[0254] (Components in process 1C)

[0255] The polypropylene, acid components, aromatic hydrocarbon solvents, and reaction solvents used as components in step 1C of manufacturing method C are the same as those used in step 1A of manufacturing method A.

[0256] (Heating to dissolve)

[0257] The conditions for heating and melting can be the same as those described for step 1A of manufacturing method A.

[0258] [Manufacturing method C: Step 2C]

[0259] Step 2C in manufacturing method C is a step in which an organic peroxide is added to the solution 1C to obtain a solution 2C containing a crude polymer composition of acid-modified polypropylene.

[0260] (Components in process 2C)

[0261] The organic peroxide used as a component in step 2C of manufacturing method C is the same as the organic peroxide described in step 2A of manufacturing method A. The crude polymer composition used as a component in step 2C of manufacturing method C will be described in detail below.

[0262] • Crude polymer composition

[0263] The crude polymer composition is the same as described in the above-described <Polymer Composition> section, except that the total content of dimethylfuran compounds relative to the total mass is not limited to less than 15 ppm by mass. Furthermore, the preferred range is also the same. That is, the total content of dimethylfuran compounds relative to the total mass of the crude polymer composition can be 15 ppm by mass or more, or it can be less than 15 ppm by mass.

[0264] When a very low concentration of dimethylfuran compounds relative to the total mass of the polymer composition is required, even if this concentration is less than 15 ppm by mass, further purification of the polymer composition is sometimes necessary. In such cases, a crude polymer composition can be formed even if the concentration of dimethylfuran compounds relative to the total mass of the polymer composition is less than 15 ppm by mass.

[0265] When the total content of dimethylfuran compounds relative to the total mass of the crude polymer composition is less than 15 ppm by mass, the preferred method for the crude polymer composition is the same as that described in the above <Polymer Compositions> section.

[0266] (Reaction conditions)

[0267] The reaction conditions after adding the organic peroxide can be the same as those described for step 2A of manufacturing method A.

[0268] [Other processes]

[0269] Manufacturing method C may include any steps in addition to those described above. Examples of such steps include: nitrogen bubbling of the reaction solution before the addition of the organic peroxide, extraction of the reaction solution using water, decolorization of the reaction solution, drying of the acid-modified polypropylene, and pulverization of the acid-modified polypropylene.

[0270] <Method for manufacturing crude polymer composition>

[0271] The method for manufacturing the crude polymer composition according to embodiments of the present invention is a method for manufacturing a crude polymer composition containing acid-modified polypropylene and at least one dimethylfuran compound selected from the group consisting of 2,5-dimethylfuran, 2,4-dimethylfuran and 3,4-dimethylfuran, which sequentially includes the following steps 1D to 3D (hereinafter also referred to as "manufacturing method D").

[0272] (Process 1D)

[0273] In a reaction solvent comprising aromatic hydrocarbon solvents and at least one selected from the group consisting of acetone and its derivatives,

[0274] The process involves heating and dissolving polypropylene and at least one acid component selected from the group consisting of unsaturated carboxylic acids and their derivatives to obtain a solution 1D containing said polypropylene and said acid component.

[0275] (Process 2D)

[0276] The process involves adding an organic peroxide to the solution 1D to obtain a solution 2D containing acid-modified polypropylene.

[0277] (Process 3D)

[0278] The process of separating the solution into a crude polymer composition and a filtrate to obtain the crude polymer composition.

[0279] The method for manufacturing the crude polymer composition according to embodiments of the present invention can be included as a process for manufacturing the polymer composition.

[0280] The method for manufacturing the crude polymer composition according to embodiments of the present invention may include steps 4D to 5D sequentially after step 3D.

[0281] (Process 4D)

[0282] The process involves purifying the filtrate to obtain a treatment solvent.

[0283] (Process 5D)

[0284] A process in which the processing solvent is reused as part or all of the reaction solvent in step 1D.

[0285] [Manufacturing Method D: Process 1D]

[0286] Step 1D in manufacturing method D involves heating and dissolving polypropylene and at least one acid component selected from the group consisting of an aromatic hydrocarbon solvent and at least one of the group consisting of acetone and its derivatives in a reaction solvent to obtain a solution 1D containing said polypropylene and said acid component.

[0287] (Components in process 1D)

[0288] The polypropylene, acid components, aromatic hydrocarbon solvents, and reaction solvents used as components in step 1D of manufacturing method D are the same as those used in step 1A of manufacturing method A.

[0289] (Heating to dissolve)

[0290] The conditions for heating and melting can be the same as those described for step 1A of manufacturing method A.

[0291] [Manufacturing Method D: Process 2D]

[0292] Step 2D in manufacturing method D is a step in which an organic peroxide is added to the solution 1D to obtain a solution 2D containing acid-modified polypropylene.

[0293] The organic peroxide used as a component in step 2D of manufacturing method D is the same as the organic peroxide used in step 2A of manufacturing method A.

[0294] (Reaction conditions)

[0295] The reaction conditions after adding the organic peroxide can be the same as those described for step 2A of manufacturing method A.

[0296] [Manufacturing Method D: Process 3D]

[0297] Step 3D in manufacturing method D is the step of separating the solution 2D into a crude polymer composition and a filtrate to obtain the crude polymer composition.

[0298] (Components in process 3D)

[0299] The filtrate used as a component in step 3D of manufacturing method D is the same as the filtrate used in step 3A of manufacturing method A.

[0300] (Method for separating polymer compositions from solution 2D)

[0301] The method for separating the polymer composition from the solution 2D can use the same method as described in step 3A of manufacturing method A. For example, step 3D may include a step of separating the solution 2D into the polymer composition and the filtrate by crystallization purification.

[0302] [Manufacturing Method D: Process 4D]

[0303] Step 4D in manufacturing method D is the process of purifying the filtrate to obtain the treatment solvent.

[0304] (Components in process 4D)

[0305] The processing solvent used as a component in step 4D of manufacturing method D is the same as the solvent used in step 4A of manufacturing method A. For example, the content of at least one component selected from the group consisting of acetone and its derivatives relative to the total mass of the processing solvent is preferably 0.2% by mass or less, more preferably 0.15% by mass or less, and even more preferably 0.1% by mass or less. The lower the content, the better, and there is no particular limitation on the lower limit; for example, it can be set to 0.001% by mass or more, 0.005% by mass or more, or 0.01% by mass or more.

[0306] (Methods for obtaining processing solvents)

[0307] The treatment solvent is obtained by purifying the filtrate. The purification method can be the same as that described in step 4A of manufacturing method A. For example, the purification process in step 4D preferably includes distillation purification. Furthermore, distillation purification can also be performed using the same distillation purification method described in step 4A of manufacturing method A.

[0308] [Manufacturing Method D: Process 5D]

[0309] Step 5D in manufacturing method D is a step in which the processing solvent obtained in step 4D is reused as part or all of the reaction solvent in step 1D.

[0310] The method of reusing the processing solvent obtained in step 4D as the reaction solvent in step 1D can be the same as the method described for step 5A of manufacturing method A.

[0311] [Other processes]

[0312] Manufacturing method D may include any steps in addition to those described above. Examples of such steps include: nitrogen bubbling of the reaction solution before the addition of the organic peroxide, extraction of the reaction solution using water, decolorization of the reaction solution, drying of the acid-modified polypropylene, and pulverization of the acid-modified polypropylene.

[0313] Example

[0314] <Preparation of Polymer Compositions>

[0315] [Example 1]

[0316] <Reaction Solvent>

[0317] Isopropyl propylene homopolymer, maleic anhydride, and monochlorobenzene were added to a glass flask equipped with a stirrer, thermometer, reflux condenser, and dropping funnel, and dissolved under a nitrogen atmosphere. Then, dicumyl peroxide, as an organic peroxide, was added to react with the solution, yielding a solvent. Acetone was added to this solvent, and the polymer precipitated through crystallization was separated by filtration, yielding a filtrate. This filtrate was purified by distillation and used as a reaction solvent, which was subsequently reused in the manufacture of the polymer composition of Example 1. The reaction solvent used in Example 1 was monochlorobenzene containing 13 ppm by mass of acetone and 53 ppm by mass of isopropylidene acetone.

[0318] (Preparation of polymer compositions)

[0319] 100 parts by mass of isotactic propylene homopolymer with an MFR of 10 g / 10 min (determined according to JIS K 7210: 2014 at 230 °C and 21.2 N), 19 parts by mass of maleic anhydride, and 750 parts by mass of reaction solvent were added to a glass flask equipped with a stirrer, thermometer, reflux condenser, and dropping funnel, and dissolved under a nitrogen atmosphere at 127 °C. At the same temperature, 7 parts by mass of dicumyl peroxide as an organic peroxide were added from the dropping funnel, and the mixture was stirred continuously for 9 hours to allow the reaction to proceed. After the reaction was complete, the reaction solution was cooled to near room temperature, and acetone was added, causing the polymer to precipitate. The precipitated polymer was filtered and separated, and the filtered polymer was repeatedly washed with acetone to form a slurry. The washed polymer was dried under reduced pressure to obtain the polymer composition of Example 1 as a white powder.

[0320] [Example 2]

[0321] As the reaction solvent, monochlorobenzene containing 274 ppm by mass of acetone and 42 ppm by mass of isopropylidene acetone was used. Otherwise, the polymer composition of Example 2 was obtained in the form of a white powder by the same method as in Example 1.

[0322] [Example 3]

[0323] As the reaction solvent, monochlorobenzene containing 503 ppm by mass of acetone and 37 ppm by mass of isopropylidene acetone was used. Otherwise, the polymer composition of Example 3 was obtained in the form of a white powder by the same method as in Example 1.

[0324] [Comparative Example 1]

[0325] As the reaction solvent, monochlorobenzene containing 688 ppm by mass of acetone and 96 ppm by mass of isopropylidene acetone was used. Otherwise, the polymer composition of Comparative Example 1 was obtained in the form of a white powder by the same method as in Example 1.

[0326] Quantitative analysis of dimethylfuran compounds in polymer compositions

[0327] The quantification of dimethylfuran compounds in the polymer composition was performed using thermal extraction GC / MS (Agilent 7890 / Agilent 5977A, manufactured by Agilent Technologies) with 2,5-dimethylfuran (manufactured by Fujifilm and Kojun Chemical Co., Ltd.) as the standard sample. Sample preparation and GC / MS analytical conditions are as follows.

[0328] It should be noted that, as a dimethylfuran compound, it includes at least one or all of 2,5-dimethylfuran, 2,4-dimethylfuran, and 3,4-dimethylfuran. The total content of dimethylfuran compounds in this specification refers to the value when 2,5-dimethylfuran is used as a standard sample for determination.

[0329] (Sample preparation)

[0330] 10 mg of the polymer composition obtained in the examples and comparative examples was weighed and inserted into a thermal desorption tube (manufactured by Gerstel). After inserting the thermal desorption tube into a 40°C thermal desorption apparatus (TDU, manufactured by Gerstel), the tube was purged with helium and heated to 180°C at a rate of 12°C / s for 10 minutes for thermal extraction. During this thermal extraction, the GC inlet CIS4 (manufactured by Gerstel) filled with quartz wool was cooled to -150°C, thereby trapping volatile components generated by the sample. The components trapped at the GC inlet were vaporized by rapidly heating the trapped portion to 300°C and introduced into a GC column for GC / MS (Agilent 7890 / Agilent 5977A) analysis.

[0331] (GC / MS determination conditions)

[0332] • Column: DB-5MSUI 30m×250μm×0.25μm

[0333] • Column flow rate: 1.0 m³ / min

[0334] • Carrier gas: He

[0335] • Oven temperature: Hold at 40°C for 5 minutes, then increase the temperature to 300°C at a rate of 10°C / minute. Hold at 300°C for another 20 minutes.

[0336] • Injection mode: Solvent

[0337] • Flow split ratio: 1:50

[0338] • Measurement mode: EI Scan

[0339] <Determination of YI in Sheet-like Polymer Compositions>

[0340] (Sample preparation)

[0341] Sheets (200×200×2mm thick) of the polymer compositions obtained in the Examples and Comparative Examples were made using a compression molding machine (SHINTO F-type hydraulic press NF-37H, manufactured by Shinto Metal Industries, Ltd.).

[0342] The measurement conditions are as follows.

[0343] ・ Heating temperature: 160 °C

[0344] ・ Preheating time: 5 minutes, without pressure

[0345] ・ Pressurization conditions: 8 MPa, 2 minutes

[0346] ・ Cooling conditions: 10 MPa, 2 minutes

[0347] <Measurement of YI>

[0348] Using a color difference meter ZE6000 manufactured by Nippon Denshoku Industries Co., Ltd., measure the YI of the obtained sheet.

[0349] <Measurement results>

[0350] The total content ratio of dimethylfuran compounds in the polymer compositions obtained in each of the examples and comparative examples and the YI of the sheet-like polymer compositions are shown in Table 1.

[0351] [Table 1]

[0352]

[0353] As shown in Table 1, the polymer compositions of Examples 1 to 3 in which the total content ratio of dimethylfuran compounds is less than 15 mass ppm showed a lower YI compared to Comparative Example 1.

[0354] As described above, various embodiments have been described. Needless to say, the present invention is not limited to these examples. Obviously, those skilled in the art can conceive of various modification examples or correction examples within the scope described in the claims, and it should be understood that these also naturally belong to the technical scope of the present invention. In addition, the constituent elements in the above-described embodiments can be arbitrarily combined without departing from the gist of the invention.

[0355] It should be noted that this application is based on a Japanese patent application (Japanese Patent Application No. 2024-001830) filed on January 10, 2024, the content of which is incorporated herein by reference.

[0356] Industrial applicability

[0357] The polymer compositions of the embodiments of the present invention have minimal hue variation in the molded articles, particularly a low yellowness (YI) value. Therefore, they are suitable for, for example, food packaging materials such as films and trays for food packaging; medical packaging materials such as infusion bags, nutritional food / liquid food bags, and ostomy bags; medical device components that combine injection-molded parts such as drip tubes and syringes with metal needles; fluid delivery devices such as bottles and tubes used in medical applications; medical supplies such as medicine containers such as medicine tubes and medicine bottles; automotive components such as fuel tanks, fuel lines, automotive coolant lines, especially electric vehicle coolant lines; and battery components such as outer casing films and tab lead films for secondary batteries in the fields of electronics, automobiles, and robotics.

Claims

1. A polymer composition comprising acid-modified polypropylene and at least one dimethylfuran compound selected from the group consisting of 2,5-dimethylfuran, 2,4-dimethylfuran, and 3,4-dimethylfuran. The total content of the dimethylfuran compound relative to the total mass of the polymer composition is less than 15 ppm by mass.

2. The polymer composition according to claim 1, wherein, The total content of the dimethylfuran compound relative to the total mass of the polymer composition is 0.5 ppm by mass or more.

3. The polymer composition according to claim 1, wherein, The total content of the dimethylfuran compound relative to the total mass of the polymer composition is 1 ppm or more.

4. The polymer composition according to claim 1, wherein, The total content of the dimethylfuran compound relative to the total mass of the polymer composition is less than 12 ppm by mass.

5. The polymer composition according to claim 1, wherein, The polymer composition has a melt flow rate of 150–2000 g / 10 min as determined by JIS K 7210:2014 at 180 °C and a load of 21.2 N.

6. The polymer composition according to claim 1, wherein, The grafting rate of the acid-modified polypropylene is 1.0 to 20% by mass.

7. A food packaging material comprising a polymer composition according to any one of claims 1 to 6.

8. A medical product comprising a polymer composition according to any one of claims 1 to 6.

9. An automotive component comprising the polymer composition according to any one of claims 1 to 6.

10. A battery component comprising a polymer composition according to any one of claims 1 to 6.

11. Use of a polymer composition in food packaging materials, said polymer composition being the polymer composition according to any one of claims 1 to 6.

12. Use of a polymer composition in a medical product, said polymer composition being the polymer composition according to any one of claims 1 to 6.

13. Use of a polymer composition in an automotive component, said polymer composition being the polymer composition according to any one of claims 1 to 6.

14. Use of a polymer composition in a battery component, said polymer composition being the polymer composition according to any one of claims 1 to 6.

15. A method for manufacturing a polymer composition, said polymer composition being the polymer composition according to any one of claims 1 to 6. The manufacturing method includes the following steps 1A to 5A in sequence: Process 1A: In a reaction solvent comprising aromatic hydrocarbon solvents and at least one selected from the group consisting of acetone and its derivatives, The process involves heating and dissolving polypropylene and at least one acid component selected from the group consisting of unsaturated carboxylic acids and their derivatives to obtain a solution 1A containing the polypropylene and the acid component. Process 2A: The process of adding an organic peroxide to the solution 1A to obtain a solution 2A containing acid-modified polypropylene; Process 3A: The process of separating the solution 2A into a polymer composition and a filtrate to obtain the polymer composition; Process 4A: The process of purifying the filtrate to obtain a treatment solvent; Process 5A: A process in which the processing solvent is reused as part or all of the reaction solvent in step 1A.

16. The manufacturing method according to claim 15, wherein, The step 3A includes the step of separating the solution 2A into the polymer composition and the filtrate by crystallization purification.

17. The manufacturing method according to claim 15, wherein, The purification process in step 4A includes distillation purification.

18. The manufacturing method according to claim 15, wherein, The total content of at least one of the group consisting of acetone and its derivatives is less than 0.2% by mass relative to the total mass of the processing solvent.

19. A method for manufacturing a polymer composition, said polymer composition being the polymer composition according to any one of claims 1 to 6. The manufacturing method includes the following steps 1B to 4B in sequence: Process 1B: In a reaction solvent comprising aromatic hydrocarbon solvents and at least one selected from the group consisting of acetone and its derivatives, The process involves heating and dissolving polypropylene and at least one acid component selected from the group consisting of unsaturated carboxylic acids and their derivatives to obtain a solution 1B containing the polypropylene and the acid component. Process 2B: The process of adding an organic peroxide to the solution 1B to obtain a solution 2B containing acid-modified polypropylene. Process 3B: The process of separating the solution 2B into a polymer composition and a filtrate by crystallization purification to obtain the polymer composition; Process 4B: The process of purifying the filtrate by distillation.

20. A method for producing a solution of a crude polymer composition, wherein the solution contains acid-modified polypropylene and at least one dimethylfuran compound selected from the group consisting of 2,5-dimethylfuran, 2,4-dimethylfuran, and 3,4-dimethylfuran. The manufacturing method includes the following steps 1C to 2C in sequence: Process 1C: In a reaction solvent comprising aromatic hydrocarbon solvents and at least one selected from the group consisting of acetone and its derivatives, The process involves heating and dissolving polypropylene and at least one acid component selected from the group consisting of unsaturated carboxylic acids and their derivatives to obtain a solution 1C containing said polypropylene and said acid component. Process 2C: The step of adding an organic peroxide to the solution 1C to obtain a solution 2C containing a crude polymer composition of acid-modified polypropylene.

21. A method for manufacturing a crude polymer composition, said crude polymer composition comprising acid-modified polypropylene and at least one dimethylfuran compound selected from the group consisting of 2,5-dimethylfuran, 2,4-dimethylfuran, and 3,4-dimethylfuran. The manufacturing method includes the following steps 1D to 3D in sequence: Process 1D: In a reaction solvent comprising aromatic hydrocarbon solvents and at least one selected from the group consisting of acetone and its derivatives, The process involves heating and dissolving polypropylene and at least one acid component selected from the group consisting of unsaturated carboxylic acids and their derivatives to obtain a solution 1D containing said polypropylene and said acid component. Process 2D: The process of adding an organic peroxide to the solution 1D to obtain a solution 2D containing acid-modified polypropylene. 3D Process: The process of separating the solution into a crude polymer composition and a filtrate to obtain the crude polymer composition.

22. The manufacturing method according to claim 21, wherein, The manufacturing method includes steps 4D to 5D sequentially after step 3D: Process 4D: The process of purifying the filtrate to obtain a treatment solvent; Process 5D: A process in which the processing solvent is reused as part or all of the reaction solvent in step 1D.

23. The manufacturing method according to claim 21, wherein, The process 3D includes the step of separating the solution 2D into the crude polymer composition and the filtrate through crystallization purification.

24. The manufacturing method according to claim 22, wherein, The purification process in step 4D includes distillation purification.

25. The manufacturing method according to claim 22, wherein, The total content of at least one of the group consisting of acetone and its derivatives is less than 0.2% by mass relative to the total mass of the processing solvent.

26. The manufacturing method according to claim 21, wherein, The total content of the dimethylfuran compound relative to the total mass of the crude polymer composition is less than 15 ppm by mass.

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