Thermoplastic resin manufacturing method

Abstract

To provide a method for producing a thermoplastic resin to which ion crosslinking is introduced without requiring a high temperature condition.SOLUTION: A method for producing a thermoplastic resin includes a step of mixing a polymer (A) containing a carboxyl group and a hydrate salt (B).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing a thermoplastic resin. [Background technology]

[0002] Thermoplastic resins can be molded into various shapes due to their moldability, and are used in a wide range of applications, including containers, Used in a wide range of industrial applications, including fixtures, display components, electrical appliances, and automotive components. .

[0003] Thermoplastic resins are given additional physical properties, such as toughness, scratch resistance, chemical resistance, and impact resistance. In order to provide this property, it has been proposed to introduce a crosslinked structure into the resin. The addition of the above physical properties results in a decrease in moldability, which is a characteristic of thermoplastic resins.

[0004] Therefore, a cross-linked structure is formed in the temperature range in use, and de-cross-linking occurs at high temperatures during molding. Ion crosslinking is used as a crosslinking technology to introduce ion crosslinks into thermoplastic resins. By doing so, the physical properties due to the crosslinking can be improved while maintaining the molding processability of a thermoplastic resin. As a method for forming an ionic crosslinked structure, Patent Document 1 discloses a method for forming an ionic crosslinked structure using a vinyl monomer. It is disclosed that a copolymer consisting of a dimer and an unsaturated carboxylic acid is reacted with a metal ion crosslinking agent. Patent Document 2 discloses a method for blending calcium carbonate with a partially neutralized metal ionomer. ionizing a portion of the free carboxyl groups of the partially neutralized metal ionomer; Patent Document 3 describes a method for producing a carboxylic acid compound having a carboxyl group and / or a dicarboxylic acid anhydride group. At least a part of which is at least one metal ion selected from Group 1, Group 2, or Group 12 of the periodic table It is described that the metal carboxylate is converted into a metal-containing carboxylate containing amine. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 47-39240 [Patent Document 2] Patent Publication No. Heisei 9-221571 [Patent Document 3] Patent Publication No. 2021-1332 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in Patent Documents 1 to 3, the reaction temperature range is 200°C or more and 250°C or less. It is disclosed that ionic bridges are introduced, but the metal ions used in Patent Documents 1 to 3 an on-crosslinking agent, calcium carbonate, at least one selected from Group 1, Group 2, or Group 12 of the Periodic Table None of the metal ions in the above-mentioned compounds are hydrates or derived therefrom. Such high temperature conditions may cause the resin to undergo thermal decomposition, resulting in a deterioration in the physical properties of the resin.

[0007] The object of the present invention is to provide a polymerizable composition that does not require high temperature conditions as in the past, but which introduces ionic crosslinking. The present invention provides a method for producing a thermoplastic resin. [Means for solving the problem]

[0008] As a result of extensive research by the present inventors, it was found that a polymer containing a carboxyl group and a polymer containing a metal ion The above problem can be solved by mixing a hydrate of a salt containing the compound with a hydrate of the compound, i.e., a salt hydrate. We have discovered this and completed the present invention.

[0009] That is, the present invention provides the following. [1] A heat treatment method including a step of mixing a polymer (A) containing a carboxyl group with a hydrated salt (B). A method for producing plastic resins. [2] The temperature in the mixing step is 30°C or higher and 190°C or lower. A method for producing plastic resins. [3] The total mass of the polymer (A) and the hydrate salt (B) during the mixing step is 100%. The ratio of the hydrate salt (B) to the total weight of the mixture is in the range of 1 part by mass to 50 parts by mass. A method for producing the thermoplastic resin according to [1] or [2]. [4] The polymer (A) contains a structural unit represented by the following formula (1), [1] to [3] ] A method for producing the thermoplastic resin composition according to any one of claims 1 to 4. [ka] (In formula (1), R1 to R3 each independently represent a hydrogen atom, a methyl group, a carboxyl group, or a methyl group.) It represents a silyl group or a methylenecarboxyl group. [5] In the mixing step, the polymer (A) is melted and the hydrate ( The method for producing a thermoplastic resin according to any one of [1] to [4], wherein B) is mixed. [6] The hydrate salt (B) is sodium, calcium, aluminum, magnesium, and zinc, [1] to [5] 10. The method for producing the thermoplastic resin according to claim 9, wherein the thermoplastic resin is a resin having a molecular weight of 100 or more. [7] The hydrate salt (B) is a salt selected from the group consisting of carbonates, acetates, and hydrochlorides. The thermoplastic resin according to any one of [1] to [6], which contains at least one hydrate of Manufacturing method. [8] Any of [1] to [5], wherein the hydrate salt (B) is a hydrate of sodium carbonate. A method for producing the thermoplastic resin according to any one of claims 1 to 4. [Effects of the Invention]

[0010] According to the present invention, in order to suitably obtain an ionically crosslinked thermoplastic resin that does not require high temperature conditions, A manufacturing method for the same can be provided. DETAILED DESCRIPTION OF THE INVENTION

[0011] The method for producing the thermoplastic resin of the present invention will be described in detail below.

[0012] In the present invention, a "group" refers to a specific chemical structure, and includes substituents and functional groups. The name given to the chemical structure is "a" and is called an "a group." The term "polymer" refers to a compound formed by polymerizing monomers. The polymer may be produced by known chemical polymerization such as radical polymerization, ionic polymerization, coordination polymerization, polycondensation, or polyaddition. Synthetic polymers obtained by chemical reactions and natural polymers produced by biosynthesis are made up of monomers. There are no particular limitations on the polymer as long as it can be constructed from the above. The term "salt" refers to the compound used in the synthesis of a compound, which is also called a monomer. It refers to a compound that is produced by the reaction of an acid with a negative component and a base with a positive component. A salt in which the negative component of the acid is b is described as "b salt." "Thermoplastic resin" refers to a resin that can be made by heating. A "structural unit" is a resin that exhibits the property of softening when heated and hardening when cooled. It may be a structural unit introduced by polymerization of a monomer, and a specific The structural unit may be a structural unit that has been converted by modifying the structural unit through a reaction. The structural units introduced by polymerization are called monomer units. "Monomer" refers to the monomer having a carbon-carbon bond in its chemical structure that causes a polymerization reaction. "(Meth)acrylate" refers to an acrylate or methacrylate. refers to acrylate. In the present specification, "parts by mass" refers to the weight of each component relative to the total weight of the components. Refers to the quantity fraction.

[0013] The method for producing a thermoplastic resin in the present invention comprises: and (B) a salt hydrate.

[0014] [Polymer (A)] The polymer (A) contains a carboxyl group in its molecule. The amount of carboxyl groups to be added is 0.05 mmol or more per 1 g of polymer (A). It is preferable that the concentration is 0.1 mmol or more, more preferable that the concentration is 0.2 mmol or more. The amount of carboxyl groups contained in polymer (A) is 0. If the amount is 0.5 mmol or more, the strength, toughness, and chemical resistance of the resulting thermoplastic resin will be good. The amount of carboxyl groups contained in the polymer (A) is, relative to 1 g of the polymer (A), Preferably it is 7 mmol or less, more preferably 6 mmol or less, and more preferably 5 mmol or less It is more preferable that the amount of carboxyl groups contained in the polymer (A) is 100% or more per 1 g of the polymer (A). On the other hand, if the amount is 7 mmol or less, the processability of the resulting thermoplastic resin will be good.

[0015] The method for producing the polymer (A) includes a method for producing a polymer containing at least a monomer having a carboxyl group. The polymerizable composition can be obtained by polymerizing components containing the polymerizable composition. There is no particular limitation on the polymerization method. For example, known polymerization methods such as radical polymerization, ionic polymerization, coordination polymerization, polycondensation, and polyaddition can be used. During the polymerization, a known polymerization initiator, a molecular weight modifier, etc. may be used. Furthermore, commercially available synthetic polymers or natural polymers can also be used as the polymer (A). Polymer (A) undergoes chemical reactions such as thermal decomposition and hydrolysis to remove functional groups in the polymer. The polymer (A) may be modified with a carboxyl group. It is preferable.

[0016] Among the above, the polymer (A) preferably contains a structural unit represented by the following formula (1): stomach.

[0017] [ka]

[0018] In formula (1), R1 to R3 each independently represent a hydrogen atom, a methyl group, a carboxyl group, or a methyl group. It represents a silyl group or a methylenecarboxyl group.

[0019] Among these, the structural unit represented by formula (1) is acrylic acid, methacrylic acid, maleic acid, Unsaturated carboxylic acids such as fumaric acid, itaconic acid, citraconic acid, crotonic acid, and isocrotonic acid It is more preferable that the structural unit is derived from carboxylic acid (a1). The structural unit may be one introduced by polymerizing the unsaturated carboxylic acid, or other The polymer may be one obtained by polymerizing a monomer and then modifying it by a chemical reaction.

[0020] [Unsaturated carboxylic acid (a1)] Unsaturated carboxylic acids are monomers that have a polymerizable double bond group and a carboxyl group in the molecule. The unsaturated carboxylic acid may be one represented by the following formula (2):

[0021] [ka]

[0022] In formula (2), R4 to R6 each independently represent a hydrogen atom, a methyl group, a carboxyl group, or a methyl group. It represents a silyl group or a methylenecarboxyl group. Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, and fumaric acid. Examples of suitable carboxylic acids include hydroxybenzoates, itaconic acid, citraconic acid, crotonic acid, and isocrotonic acid. Among these, acrylic acid or methacrylic acid is preferred because of its easy availability.

[0023] The structural unit represented by formula (1) in 100 parts by mass of the structural unit constituting the polymer (A) The proportion is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more. When the ratio is 1 part by mass or more, ionic crosslinking is more easily formed, and the obtained The strength, toughness, and chemical resistance of the thermoplastic resin to be used can be expected to be improved. 50 parts by mass or less is preferable, 40 parts by mass or less is more preferable, and 30 parts by mass or less is even more preferable. If the ratio is 50 parts by mass or less, the processability of the obtained thermoplastic resin is better. This becomes:

[0024] When the polymer (A) has a structural unit represented by formula (1), it may further contain a vinyl monomer ( It may contain structural units derived from a2).

[0025] [Vinyl monomer (a2)] The vinyl monomer (a2) is a monomer copolymerizable with the unsaturated carboxylic acid (a1). Therefore, it is a monomer different from the unsaturated carboxylic acid (a1). Examples of such unsaturated aromatic monomers include styrene and α-methylstyrene; methyl (meth)acrylate; Acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (Meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate Acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, etc. Meth)acrylic acid alkyl ester; phenyl (meth)acrylate, benzyl (meth)acrylate (Meth)acrylic acid aralkyl esters such as acrylates; 2-hydroxyethyl (meth)acrylic acid aralkyl esters such as acrylates; ) acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxy Hydroxyl group-containing acrylates such as butyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate (Meth)acrylic acid esters; vinyl esters such as vinyl acetate and isopropenyl acetate ;Methyl vinyl ether, ethyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, 2-ethylhexyl vinyl ether, etc. vinyl ether; (meth)acrylamide, etc. Polymerization is carried out using known reactions. From the viewpoint of ease of use, (meth)acrylic acid alkyl esters are preferred, and among them, methacrylic acid alkyl esters are preferred. butyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate More preferred are 2-ethylhexyl (meth)acrylate and 2-ethylhexyl (meth)acrylate. Only one type may be used, or two or more types may be used.

[0026] The proportion of the vinyl monomer (a2) in 100 parts by mass of the structural units constituting the polymer (A) The proportion of the structural unit is preferably 50 parts by mass or more, more preferably 60 parts by mass or more, and more preferably 70 parts by mass or more. If the ratio is 50 parts by mass or more, the thermoplastic resin obtained The proportion is preferably 99 parts by mass or less, and more preferably 95 parts by mass or less. More preferably, the ratio is 99 parts by mass or less, and even more preferably 90 parts by mass or less. Ionic crosslinks are more likely to form, improving the strength, toughness, and chemical resistance of the resulting thermoplastic resin. Improved quality can be expected.

[0027] The weight average molecular weight of the polymer (A) is not particularly limited, but is preferably 500 or more. It is preferable that the number of carbon atoms is 1000 or more, and more preferable that the number of carbon atoms is 2000 or more. If the weight average molecular weight is 500 or more, the strength of the resulting thermoplastic resin will be good. On the other hand, it is preferably 2 million or less, more preferably 1.5 million or less, It is more preferable that the weight average molecular weight is 1 million or less. The processability of the resulting thermoplastic resin is improved. Using quasi-polymethyl methacrylate as a calibration curve, the gel was analyzed using tetrahydrofuran as an eluent. The weight of polymer (A) is determined by permeation chromatography. The average molecular weight can be adjusted by, for example, the concentration of the polymerization initiator, the use of a chain transfer agent, and the composition of the polymerization solvent. It is possible.

[0028] [Hydrate (B)] The hydrate salt (B) is a salt containing metal ions and contains 0.1 or more water of hydration. The number of water of hydration contained in the hydrate (B) is preferably 0.5 or more, more preferably 1 or more, It is more preferable that the hydrate salt (B) has 0.5 or more water of hydration, so that the released The metal ions dissolve in the hydrated water and are easily mixed uniformly with the polymer (A). The number of waters of hydration contained in B) is preferably 20 or less, more preferably 18 or less, and most preferably 15 or less. It is more preferable that the hydrate (B) has 20 or less water of hydration, and therefore the hydrate (B) can be easily mixed with the polymer (A). In this case, the amount of gas generated is suppressed.

[0029] The metal ions constituting the hydrate (B) include alkali metals, alkaline earth metals, periodic Examples of metal ions include those derived from metal elements belonging to groups 3 to 13 in the table. As the ion, sodium, calcium, aluminum, etc. are preferred from the viewpoint of good ionic reactivity. Preferred are metal ions selected from the group consisting of aluminum, magnesium, and zinc. In addition, in the manufacturing process, the hydrate salt (B) is preferably charcoal, from the viewpoint that decomposition products are easily removed. The compound may contain at least one hydrate of a salt selected from the group consisting of acid salts, acetate salts, and hydrochloride salts. is more preferable. Such hydrated salts include sodium carbonate monohydrate, sodium carbonate decahydrate, Calcium carbonate hexahydrate, aluminum carbonate hexahydrate, magnesium carbonate dihydrate, magnesium carbonate Hydrates of carbonates such as magnesium trihydrate, magnesium carbonate pentahydrate, and basic zinc carbonate Sodium acetate trihydrate, calcium acetate monohydrate, magnesium acetate tetrahydrate, acetic acid Hydrated acetates such as zinc dihydrate; sodium chloride dihydrate, calcium chloride dihydrate , hydrated hydrochlorides such as zinc chloride 1.5hydrate, zinc chloride 2.5hydrate, and zinc chloride trihydrate These hydrated salts may be used alone or in combination of two or more. Among these, hydrated salts are preferred from the viewpoint of low toxicity of decomposition products generated after the reaction. It is further preferred that (B) is selected from carbonate hydrates.

[0030] [Method of manufacturing thermoplastic resin] The present invention includes a step of mixing a polymer (A) containing a carboxyl group with a hydrated salt (B). In order to efficiently mix the components, the polymer (A) is It is preferable to mix the polymer (A) and the hydrate salt (B) in a molten state. By mixing, i.e., kneading, the polymer (A) and the hydrated salt (B) are uniformly mixed. The temperature in the mixing step, i.e., the temperature in the melt-kneading step, can be There are no particular limitations, but the temperature should be equal to or higher than the temperature at which the polymer (A) softens, and is preferably 30°C or higher. Preferably, the temperature is 50°C or higher, more preferably 100°C or higher. If the above condition is met, ions are more likely to be generated by the release of water of hydration from the hydrated salt (B). The temperature is preferably 190°C or less, more preferably 180°C or less, and even more preferably 170°C or less. If the temperature is 190°C or lower, the polymer (A) is not thermally decomposed and / or modified. This makes it easier to suppress the deterioration of material properties.

[0031] The polymer (A) and the hydrate salt (B) can be mixed using a known device. Examples of the equipment that can be used include a single-screw extruder, a twin-screw extruder, a roll mill, and a Banbury mixer. By discharging the water and gas produced by the reaction, the reaction can proceed more easily. From the viewpoint of reducing the amount of air that can be removed, it is preferable to use an apparatus equipped with a degassing device such as a vent extruder.

[0032] The mixing time of the polymer (A) and the hydrated salt (B) is determined based on the reaction time between the polymer (A) and the hydrated salt (B). There is no particular limitation as long as the mixing time is sufficient for the progress, but 3 minutes or more is preferable. The mixing time is preferably 5 minutes or more, and more preferably 10 minutes or more. In addition, from the viewpoint of suppressing thermal decomposition of the polymer (A), the mixing time is The time is preferably 120 minutes or less, more preferably 60 minutes or less, and even more preferably 30 minutes or less. If the mixing time is 120 minutes or less, the thermal decomposition and deterioration of the polymer (A) are easily suppressed. do.

[0033] The mixing ratio of the polymer (A) and the hydrate salt (B) in the mixing step is determined based on the carbon content of the polymer (A). The equivalent amount of metal ions generated from the hydrate salt (B) is used to react with the carboxyl group. The total amount of the polymer (A) and the hydrate salt (B) can be selected arbitrarily. The ratio of the hydrate (B) to the total weight of the cellulose is preferably 1 part by mass or more, and more preferably 5 parts by mass or more. It is more preferable that the ratio is 1 part by mass or more, and even more preferable that the ratio is 10 parts by mass or more. If the temperature is above 100°C, ionic crosslinking is more likely to be formed, and the strength and toughness of the resulting thermoplastic resin are improved. In addition, the proportion is preferably 50 parts by mass or less. It is preferably 45 parts by mass or less, more preferably 40 parts by mass or less. If the ratio is 50 parts by mass or less, the processability of the resulting thermoplastic resin is good. do.

[0034] [Ionic cross-linking] The thermoplastic resin obtained by the production method of the present invention is obtained by mixing the polymer (A) in the mixing step. The carboxyl group contained in the salt reacts with the metal ion generated from the salt hydrate (B) to form an ionized In this case, the hydrated salt (B) forms a chemical structure that is different from the anhydrous salt that does not have water of hydration. The low melting point of the salt (B) allows it to decompose easily, and the hydrated water released by the salt (B) can be converted into metal ions. The dissolution of the ion causes a reaction with the carboxyl group contained in the polymer (A). As a result, the electrostatic interactions exhibited by the ionized chemical structure are By using the polymer, ionic crosslinking occurs, in which polymers are strongly bonded to each other. The cohesive strength of the thermoplastic resin obtained by the method of the present invention is improved, and the melt viscosity is increased. At high temperatures, such as the molding temperature of plastic resins, the electrostatic interaction is weakened. It can be easily molded like general thermoplastic resins. It is formed by interactions such as (3) or (4).

[0035] COO - M n+ ... - O(OC) (3) COO - M n+ X m- ···M n+- O(OC) (4)

[0036] In equations (3) and (4), COO - or - O(CO) is the M is the metal element of the ion generated from the hydrate salt (B), and X is An anion generated from the hydrate salt (B), n and m each independently represent an integer of 1 or more and 3 or less. show.

[0037] The thermoplastic resin obtained by the production method of the present invention can be used as a molding material. The thermoplastic resin can be used alone as a molding material, but depending on the application, In addition, a thermoplastic resin composition containing other components is used as a molding material. There are no particular limitations on such other components, but for example, other The thermoplastic resin composition may contain, as other components, purple resins and other compounds. Radiation absorbers, flame retardants, antioxidants, plasticizers, lubricants, antistatic agents, surfactants, antibacterial agents, Addition of weather stabilizers, heat stabilizers, anti-slip agents, foaming agents, anti-fogging agents, impact modifiers, adhesives, etc. These resins and additives may be known materials, and each of them may contain The proportion may be selected arbitrarily depending on the application.

[0038] [Thermoplastic resin molding] The thermoplastic resin obtained by the manufacturing method of the present invention can be used in injection molding, T-die sheet molding, press molding, and the like. Various molding processes such as molding and blow molding can be carried out. The molding conditions are well known. This can be done under the following conditions.

[0039] [Application] The thermoplastic resin obtained by the production method of the present invention can be molded, for example, by the above-mentioned molding method. Resin glass, display materials, protective sheets, sealing materials, packaging films, gas barrier materials, It can be used as a rubber material, a sanitary material, etc. [Example]

[0040] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In the following examples, "parts" refers to "parts by mass."

[0041] (Weight average molecular weight) The weight average molecular weight of the polymer (A) was measured as follows. The composite (A) was dissolved and the concentration was adjusted to 0.5% by mass. Inject into the permeation chromatography device (injection volume 100 μl), and the flow rate is 1 mL / eluent: tetrahydrofuran, column temperature: 40°C, based on polymethyl methacrylate The weight average molecular weight was measured as a standard.

[0042] <Production of Dispersant 1> In a polymerization apparatus equipped with a stirrer, a condenser, a thermometer, and a nitrogen gas inlet tube, 900 ml of deionized water was added. parts, 60 parts of sodium 2-sulfoethyl methacrylate, 10 parts of potassium methacrylate, and Add 12 parts of methyl methacrylate (MMA) and stir. While replacing the inside of the polymerization apparatus with nitrogen, The temperature was raised to 50°C. 2,2'-azobis(2-methylpropane) 0.08 parts of pyonamidine dihydrochloride was added, and the temperature was further increased to 60°C. Using a pump, MMA was continuously added dropwise at a rate of 0.24 part / min for 75 minutes. After keeping the mixture at 60°C for 6 hours, it was cooled to room temperature and a transparent aqueous solution with a solid content of 10% by mass was obtained. Dispersant 1 was obtained.

[0043] <Synthesis of Polymer A> [Synthesis Example 1: Synthesis of Polymer (A1)] In a polymerization apparatus equipped with a stirrer, a condenser, a thermometer, and a nitrogen gas inlet tube, 145 ml of deionized water was added. parts, 0.15 parts of sodium sulfate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and the dispersant 1 Add 3.03 parts of an aqueous solution diluted with water to a solid content of 3.3% and stir to obtain a uniform aqueous solution. Next, 13 parts of methacrylic acid (MAA: manufactured by Mitsubishi Chemical Corporation), methyl methacrylate 62 parts of methyl acrylate (MMA: manufactured by Mitsubishi Chemical Corporation), 2-ethylhexyl acrylate (EHA: Mitsubishi Chemical Corporation) 15 parts, styrene (St: Fujifilm Wako Pure Chemical Industries) 10 parts, dodecyl acrylate (DMC) 10 parts 1.9 parts of Canthanethiol (Tokyo Chemical Industry Co., Ltd.), 1 part of Octanethiol (Tokyo Chemical Industry Co., Ltd.) 0.9 parts, isooctyl thioglycolate (Tokyo Chemical Industry Co., Ltd.) 1.9 parts, 3-mercapto 1.9 parts of 2-ethylhexyl propionate (Tokyo Chemical Industry Co., Ltd.), t as a polymerization initiator -Butyl 2-ethylperoxyhexanoate (trade name Perbutyl O: manufactured by NOF Corporation) 0. Eight parts of the compound was added to form an aqueous suspension. Next, the inside of the polymerization apparatus was replaced with nitrogen, the temperature was raised to 80°C, and the reaction was continued for 2 hours to further increase the polymerization rate. To achieve this, the reaction mixture was heated to 90°C and maintained at this temperature for 1 hour. An aqueous suspension containing (A1) was obtained. This aqueous suspension was filtered through a filter, and the residue on the filter was The resulting residue was washed with deionized water, dehydrated, and dried at 40°C for 16 hours to obtain polymer (A1). The amount of carboxyl groups per 1 g of the obtained polymer (A1) and the weight average The molecular weights are summarized in Table 1.

[0044] [Synthesis Example 2: Synthesis of Polymer (A2)] In a polymerization apparatus equipped with a stirrer, a condenser, a thermometer, and a nitrogen gas inlet tube, 145 ml of deionized water was added. parts, 0.15 parts of sodium sulfate, and the dispersant 1 was diluted with deionized water to a solid content of 3.3%. 3.03 parts of the aqueous solution prepared in the above was added and stirred to obtain a uniform aqueous solution. , MMA 33 parts, butyl methacrylate (BMA: manufactured by Mitsubishi Chemical Corporation) 47 parts, St10 parts, dodecanethiol 1.9 parts, octanethiol 1.9 parts, 2-ethyl thioglycolate 1.9 parts of ethylhexyl (Tokyo Chemical Industry Co., Ltd.), 2,2'-azobis(2 0.5 parts of methylbutyronitrile (Fujifilm Wako Pure Chemical Industries, Ltd.) was added to form an aqueous suspension. did. Next, the inside of the polymerization apparatus was replaced with nitrogen, the temperature was raised to 80°C, and the reaction was continued for 2 hours to further increase the polymerization rate. To achieve this, the reaction mixture was heated to 90°C and maintained at this temperature for 1 hour. An aqueous suspension containing (A2) was obtained. This aqueous suspension was filtered through a filter, and the residue on the filter was The resulting residue was washed with deionized water, dehydrated, and dried at 40°C for 16 hours to obtain polymer (A2). The amount of carboxyl groups per 1 g of the obtained polymer (A2) and the weight average The molecular weights are summarized in Table 1.

[0045] [Table 1]

[0046] [Example 1] (Production of thermoplastic resins) 82.3 parts of the polymer (A1) obtained in Synthesis Example 1 and sodium carbonate as a hydrate 17.7 parts of 10-hydrate (Fujifilm Wako Pure Chemical Industries, Ltd.) were mixed and then poured into a 60 mL The mixture was poured into a Labo Plastomill equipped with a mixer (roller mixer R60 type: manufactured by Toyo Seiki Co., Ltd.). The mixture was mixed at 180°C and 50 rpm for 20 minutes to produce a thermoplastic resin. (torque change) Torque value at 5 minutes (T5 [N·m]) and 20 minutes after kneading The difference between T20 and T5 (T20 [N·m]) was confirmed as the torque change. As the temperature was increased, the torque change increased.

[0047] (Confirmation of ionization) The obtained thermoplastic resin was cut with nippers and pressed with a hand press (Mini Test Press MP -2FH: manufactured by Toyo Seiki Co., Ltd.) was used to melt the material at 180°C for 1 minute and then pressed at 2 MPa. The film was then cooled between water-cooled cooling plates for 3 minutes to obtain a pressed film. The sample was analyzed using FT-IR (IRspirit: manufactured by Shimadzu Corporation). The infrared absorption spectrum of the sample was obtained under the following measurement conditions:

[0048] Analysis method: Transmission method Accumulation count: 60 times Resolution: 4.0cm -1 Measurement wavelength: 400 to 4000 cm -1

[0049] In the infrared absorption spectrum of the sample, 1500 to 1650 cm -1 Cal in the range COO produced by ionization of carboxylic acid - The peaks due to the antisymmetric stretching vibration of When no peak is observed, it is judged that the ionization reaction has progressed and ionic bridges have been formed, and is marked with a circle. If no ionic crosslinking was formed, the result was evaluated as x. The results are shown in Table 2. showed.

[0050] [Examples 2 to 4] Instead of polymer (A1), polymer (A2) obtained in Synthesis Example 2 was used, and the kneading The same procedure as in Example 1 was repeated except that the charge ratio and press film molding temperature were changed as shown in Table 2. The thermoplastic resin was produced and evaluated in the same manner, and the results are shown in Table 2.

[0051] [Comparative Example 1] Sodium carbonate (Fujifilm Wako Pure Chemical Industries, Ltd.) was used instead of sodium carbonate decahydrate. The mixing ratio and press film molding temperature were changed as shown in Table 2. Except for this, the thermoplastic resin was produced and evaluated in the same manner as in Example 1. Shown in Table 2.

[0052] Comparative Example 2 Polymer (A2) obtained in Synthesis Example 2 was used in place of polymer (A1), and sodium carbonate was added. Using sodium carbonate instead of sodium 10 hydrate, the mixing ratio and press fill The thermoplastic resin was prepared in the same manner as in Example 1, except that the film molding temperature was changed as shown in Table 2. The resin was produced and evaluated, and the results are shown in Table 2.

[0053] [Table 2]

[0054] As shown in Table 2, in the resin compositions obtained in Examples 1 to 4, the carboxyl groups By mixing and reacting the polymer (A) and the hydrate salt (B), ionization is ensured. On the other hand, in Comparative Examples 1 and 2, the hydrate salt (B) was replaced with anhydrous By changing to the material, there was almost no change in torque, and no progress in ionization was confirmed. Ta. [Industrial Applicability]

[0055] The thermoplastic resin obtained by the production method of the present invention has excellent mechanical strength, toughness, and chemical resistance. Resin glass, display materials, protective sheets, sealing materials, packaging films, It can be used as a gas barrier material, rubber material, sanitary material, etc., and is widely used in automobiles, construction, containers and packaging. It can be used in a wide range of industrial fields, including automotive, transportation, and medical care.

Claims

1. A method for producing a thermoplastic resin, comprising a step of mixing a carboxyl group-containing polymer (A) with a hydrate salt (B), the polymer (A) has a structural unit derived from at least one selected from the group consisting of acrylic acid and methacrylic acid, the proportion of structural units derived from at least one selected from the group consisting of acrylic acid and methacrylic acid in 100 parts by mass of structural units constituting the polymer (A) is 1 part by mass or more and 50 parts by mass or less; the polymer (A) further contains a structural unit derived from a vinyl-based monomer (a2), and the structural unit derived from the vinyl-based monomer (a2) is a structural unit derived from at least one selected from the group consisting of a (meth)acrylic acid alkyl ester, a (meth)acrylic acid aralkyl ester, a hydroxyl group-containing (meth)acrylic acid ester, a vinyl ester, a vinyl ether, and a (meth)acrylamide; Method for producing thermoplastic resins.

2. The method for producing a thermoplastic resin according to claim 1, wherein the temperature in the mixing step is 30°C or higher and 190°C or lower.

3. 3. The method for producing a thermoplastic resin according to claim 1 or 2, wherein a ratio of the hydrate salt (B) to a total of 100 parts by mass of the polymer (A) and the hydrate salt (B) during the mixing step is 1 part by mass or more and 50 parts by mass or less.

4. The method for producing a thermoplastic resin according to claim 1 , wherein the polymer (A) contains a structural unit represented by the following formula (1): 【Chemical 1】 (In formula (1), R1 to R3 each independently represent a hydrogen atom, a methyl group, a carboxyl group, or a methylenecarboxyl group.)

5. The method for producing a thermoplastic resin according to claim 1 , wherein in the mixing step, the hydrate (B) is mixed with the polymer (A) in a molten state.

6. 6. The method for producing a thermoplastic resin according to claim 1, wherein the hydrate salt (B) contains at least one metal ion selected from the group consisting of sodium, calcium, aluminum, magnesium, and zinc ions.

7. 7. The method for producing a thermoplastic resin according to claim 1, wherein the hydrate salt (B) comprises at least one hydrate of a salt selected from the group consisting of carbonates, acetates, and hydrochlorides.

8. The method for producing a thermoplastic resin according to any one of claims 1 to 5, wherein the hydrate salt (B) is a hydrate of sodium carbonate.

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