Method for producing ionomer resin granular material, and ionomer resin granular material

Abstract

To provide a method for producing an ionomer resin granular material which improves removability of salt produced by an EMMA saponification method, and is excellent in transparency.SOLUTION: A method for producing an ionomer resin granular material includes the steps of: slowly cooling a sol-like mixture containing an ionomer resin and a solvent, thereby gelling the ionomer resin in the sol-like mixture, arbitrarily crushing the gelled ionomer resin, and obtaining a porous granular ionomer resin gel; and removing the solvent from the porous granular ionomer resin gel, and obtaining an ionomer resin granular material, wherein the ionomer resin contains a (meth)acrylic acid unit (A), a neutralized (meth)acrylic acid unit (B) and an ethylene unit (C), and the total content of the unit (A) and the unit (B) is 6 mol% or more and 10 mol% or less based on the total monomer unit constituting the ionomer resin.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing ionomer resin granules, porous ionomer resin granules, a resin sheet including one or more layers containing the ionomer resin granules as a resin component, a laminated glass interlayer film made of the resin sheet, and laminated glass including the laminated glass interlayer film. [Background technology]

[0002] As one method for producing ionomer resins, a method including a step of saponifying an ethylene-(meth)acrylic acid ester copolymer as a raw material (hereinafter also referred to as the "EMMA saponification method") is known (for example, Patent Documents 1 to 3). This method has the advantage that no corrosion-resistant equipment is required, whereas other methods for producing ionomer resins including a copolymerization step of ethylene and (meth)acrylic acid (for example, Patent Document 4) require corrosion-resistant equipment. Furthermore, the EMMA saponification method can produce ionomer resins with various copolymer compositions. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 60-240704 [Patent Document 2] Patent No. 5554477 [Patent Document 3] Japanese Patent Application Publication No. 63-270709 [Patent Document 4] U.S. Patent No. 8,399,096 Summary of the Invention [Problem to be solved by the invention]

[0004] However, according to the investigations of the present inventors, it was found that the EMMA saponification method involves a saponification reaction with an alkali and a demetallation reaction with an acid, and therefore a salt is produced by a neutralization reaction between the alkali and the acid, and that the produced salt may reduce the transparency of the ionomer resin, particularly the transparency when the ionomer resin absorbs water. Therefore, the present inventors attempted to remove the salt generated by the above reactions from the ionomer resin by a method of precipitating the ionomer resin by adding a poor solvent to the reaction solution after the saponification reaction and the demetallation reaction (hereinafter, also referred to as a reprecipitation method). However, there were cases where the reprecipitation method was unable to sufficiently remove the salt.

[0005] SUMMARY OF THE PRESENT EMMA PROCESS FOR HYDROGEN SULFATE REACTION SYSTEMS . ... [Means for solving the problem]

[0006] The present inventors have conducted extensive research to solve the above problems and have arrived at the present invention. That is, the present invention provides the following preferred embodiments.

[0007] [1] A step of slowly cooling a sol-like mixture containing an ionomer resin and a solvent to gel the ionomer resin in the sol-like mixture, and optionally pulverizing the gel to obtain a porous granular ionomer resin gel; and Removing the solvent from the porous granular ionomer resin gel to obtain ionomer resin granules. Including, The ionomer resin contains (meth)acrylic acid units (A), (meth)acrylic acid neutralization units (B) and ethylene units (C), and the total content of the units (A) and the units (B) is 6 mol % or more and 10 mol % or less based on the total monomer units constituting the ionomer resin. A method for producing ionomer resin granules. [2] The method according to [1], wherein a poor solvent is not used as a refrigerant for the slow cooling. [3] The method according to [1] or [2], wherein the temperature of the sol mixture is 50°C or higher. [4] The method according to any one of [1] to [3], wherein the sol mixture is gradually cooled to a temperature of 40° C. or lower. [5] The method according to any one of [1] to [4], wherein the median diameter of the pores of the ionomer resin granules is greater than 1.2 μm and less than 50 μm. [6] The method according to any one of [1] to [5], wherein the ionomer resin granules have a porosity of 60% or more. [7] The method according to any one of [1] to [6], wherein the ionomer resin granules have a pellet shape or irregular shape with a particle size of 0.01 to 8 mm. [8] The method according to any one of [1] to [7], wherein the ionomer resin further contains (meth)acrylic acid ester units (D) in an amount of 0.01 mol % or more and 1.0 mol % or less based on all monomer units constituting the ionomer resin. [9] The method according to any one of [1] to [8], wherein the concentration of the ionomer resin in the sol-like mixture is 18.5 mass % or less based on the mass of the sol-like mixture.

[10] The method according to any one of [1] to [9], comprising washing the porous granular ionomer resin gel or ionomer resin granules with a washing liquid.

[11] The method according to

[10] , wherein the cleaning liquid is water, alcohol or a mixture thereof.

[12] The method according to any one of [1] to

[11] , wherein the content of the salt of a strong acid and a strong base in the ionomer resin contained in the sol-like mixture is 100,000 mg / kg or more.

[13] The method according to any one of [1] to

[12] , wherein the content of the salt of a strong acid and a strong base in the ionomer resin granules is 1000 mg / kg or less.

[14] The method according to any one of [1] to

[13] , wherein an ethylene-(meth)acrylic acid ester copolymer (X) is used as a raw material.

[15] A porous ionomer resin granule having a median pore size of more than 1.2 μm and not more than 50 μm.

[16] The porous ionomer resin granules according to

[15] , having a porosity of 60% or more.

[17] The porous ionomer resin granules according to

[16] , wherein the value obtained by dividing the porosity (%) by the median pore diameter (μm) is 1 to 50.

[18] A porous ionomer resin granule according to any one of

[15] to

[17] , which has a pellet shape or an irregular shape and has a particle size of 0.01 to 8 mm.

[19] The porous ionomer resin granules according to any one of

[15] to

[18] , wherein the content of the salt of a strong acid and a strong base is 1000 mg / kg or less.

[20] A resin sheet comprising at least one layer containing the porous ionomer resin granules according to any one of

[15] to

[19] as a resin component.

[21]

[20] A laminated glass interlayer comprising the resin sheet according to the present invention.

[22] A laminated glass comprising two glass sheets and the laminated glass interlayer film according to

[21] disposed between the two glass sheets. Effect of the Invention

[0008] According to the present invention, it is possible to provide a method for producing ionomer resin granules having excellent transparency by improving the removal property of the salt generated in the EMMA saponification method. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a conceptual diagram showing the X-axis length (Lx), Y-axis length (Ly), and Z-axis length (Lz) of a pellet-shaped ionomer resin granule used to calculate the particle size of the pellet-shaped ionomer resin granule, and the right-hand diagram in FIG. 1 is a plan view of the pellet-shaped ionomer resin granule shown in the left-hand diagram in FIG. 1, viewed from the X-axis direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments of the present invention will be described in detail. Note that the scope of the present invention is not limited to the embodiments described here, and various modifications can be made without departing from the spirit of the present invention.

[0011] [Method of producing ionomer resin granules] The method for producing ionomer resin granules of the present invention includes a step of slowly cooling a sol-like mixture containing an ionomer resin and a solvent to gel the ionomer resin in the sol-like mixture, and optionally pulverizing the mixture to obtain a porous granular ionomer resin gel (hereinafter also referred to as "step (I)"), and a step of removing the solvent from the porous granular ionomer resin gel to obtain ionomer resin granules (hereinafter also referred to as "step (II)"), wherein the ionomer resin contains (meth)acrylic acid units (A), (meth)acrylic acid neutralized units (B) and ethylene units (C), and the total content of the units (A) and the units (B) is 6 mol % or more and 10 mol % or less based on the total monomer units constituting the ionomer resin.

[0012] The present inventors have studied a method for removing salts generated by the saponification reaction and the demetallization reaction from an ionomer resin contained in a sol-like mixture produced by the EMMA saponification method, and have found that if the ionomer resin is made into a porous body, salts can be removed not only from the resin surface but also from the inside of the resin through the pores, thereby improving the removability of salts.The present inventors have further studied the relationship between the median diameter of the pores of the porous body and the removability of salts, and have found that if the ionomer resin is made into a porous granular material having a median diameter of pores larger than 1.2 μm and 50 μm or less, salts in the resin can be sufficiently removed, and an ionomer resin granular material having excellent transparency can be obtained, and that a porous ionomer resin having such a median pore diameter can be produced by a method including slowly cooling the sol-like mixture to gel the ionomer resin, and removing the solvent from the obtained gel. Therefore, when the ionomer resin granules are produced by the method including the steps (I) and (II), the salt in the resin can be removed, and an ionomer resin granules having excellent transparency can be obtained. The present inventors have also found that the method of the present invention can reduce the amount of solvent used and the number of washing steps, if any, compared with the reprecipitation method.

[0013] <Process (I)> Step (I) is a step of slowly cooling a sol mixture containing an ionomer resin and a solvent to gel the ionomer resin in the sol mixture, and optionally pulverizing the gel to obtain a porous granular ionomer resin gel.

[0014] (Ionomer resin contained in sol-like mixture) The ionomer resin (hereinafter also referred to as "ionomer resin (Y)") contained in the sol-like mixture in step (I) contains (meth)acrylic acid units (A), (meth)acrylic acid neutralization units (B) and ethylene units (C), and the total content of the units (A) and the units (B) is 6 mol % or more and 10 mol % or less based on all monomer units constituting the ionomer resin (Y). In this specification, the term "unit" means a "structural unit derived from", for example, a (meth)acrylic acid unit refers to a structural unit derived from (meth)acrylic acid, a (meth)acrylic acid neutralization product unit refers to a structural unit derived from a (meth)acrylic acid neutralization product, and an ethylene unit refers to a structural unit derived from ethylene. In addition, in this specification, "(meth)acrylic acid" refers to methacrylic acid or acrylic acid.

[0015] If the total content exceeds the upper limit, it is difficult to suppress the increase in melt viscosity during molding of the ionomer resin granules, and therefore the molding processability of the ionomer resin granules tends to decrease. Furthermore, if the total content is less than the lower limit, the transparency of the obtained ionomer resin granules, particularly the transparency when slowly cooled to promote crystallization of the ionomer resin (hereinafter, also referred to as transparency during slow cooling), tends to decrease. The total content is 6 mol% or more, preferably 6.5 mol% or more, more preferably 7.0 mol% or more, and even more preferably 7.5 mol% or more, from the viewpoint of improving the transparency (particularly the transparency during slow cooling) of the ionomer resin granules and the adhesion to a substrate such as glass, and is 10 mol% or less, preferably 9.9 mol% or less, and more preferably 9.5 mol% or less, from the viewpoint of improving the molding processability.

[0016] The total content of the units (A) and the units (B) can be adjusted by the production method of the ionomer resin (Y) described later. More specifically, the total content can be adjusted by the reactivity (conversion ratio) of each reaction for converting the (meth)acrylic acid ester units in the ethylene-(meth)acrylic acid ester copolymer, which is the raw material of the ionomer resin (Y), into the (meth)acrylic acid units (A) and the (meth)acrylic acid neutralized product units (B) by the saponification reaction and the demetallation reaction.

[0017] Examples of monomers constituting the (meth)acrylic acid unit (A) include acrylic acid and methacrylic acid, and from the viewpoints of heat resistance and adhesion to substrates, methacrylic acid is preferred. These (meth)acrylic acid units may be used alone or in combination of two kinds.

[0018] The content of the (meth)acrylic acid unit (A) in the ionomer resin (Y) is not particularly limited as long as the total content of the unit (A) and the unit (B) is within the range of 6 mol% to 10 mol% based on the total monomer units constituting the ionomer resin (Y). In one embodiment of the present invention, the content of the (meth)acrylic acid unit (A) in the ionomer resin (Y) is preferably 4.5 mol% or more, more preferably 5.0 mol% or more, even more preferably 5.5 mol% or more, particularly preferably 5.8 mol% or more, and also preferably 9.0 mol% or less, more preferably 8.5 mol% or less, even more preferably 8.0 mol% or less, particularly preferably 7.5 mol% or less based on the total monomer units constituting the ionomer resin (Y). When the content of the unit (A) is equal to or more than the above lower limit, the transparency of the ionomer resin granules and the adhesiveness to the substrate can be improved. When the content is equal to or less than the above upper limit, the moldability can be improved.

[0019] The (meth)acrylic acid neutralized unit (B) is preferably a neutralized unit of the (meth)acrylic acid unit (A). The (meth)acrylic acid neutralized product is a product in which the hydrogen ion of (meth)acrylic acid is replaced with a metal ion. Examples of the metal ion include ions of monovalent metals such as lithium, sodium, and potassium, and ions of polyvalent metals such as magnesium, calcium, zinc, aluminum, and titanium. Such metal ions may be used alone or in combination of two or more. For example, a combination of one or more monovalent metal ions and one or more divalent metal ions may be used.

[0020] The content of the (meth)acrylic acid neutralized unit (B) in the ionomer resin (Y) is not particularly limited as long as the total content of the unit (A) and the unit (B) is within the range of 6 mol% to 10 mol% based on the total monomer units constituting the ionomer resin (Y). In one embodiment of the present invention, the content of the (meth)acrylic acid neutralized unit (B) is preferably 0.65 mol% or more, more preferably 1.0 mol% or more, even more preferably 1.5 mol% or more, particularly preferably 1.7 mol% or more, and is preferably 3.0 mol% or less, more preferably 2.7 mol% or less, even more preferably 2.6 mol% or less, particularly preferably 2.5 mol% or less based on the total monomer units constituting the ionomer resin (Y). When the content of the unit (B) is the above lower limit or more, the transparency and elastic modulus can be improved, and when it is the above upper limit or less, the increase in melt viscosity during molding can be suppressed.

[0021] When an ionomer resin is produced using an ethylene-(meth)acrylic acid ester copolymer as a raw material by a method including a saponification reaction step and a demetallation reaction step of the copolymer, the contents of the units (A) and the units (B) can be adjusted by the degree of reaction in each reaction in which the (meth)acrylic acid ester units in the ethylene-(meth)acrylic acid ester copolymer are converted into (meth)acrylic acid units (A) and (meth)acrylic acid neutralizer units (B) by the saponification reaction and the demetallation reaction.

[0022] The content of the ethylene unit (C) is preferably 90 mol% or more, more preferably 90.5 mol% or more, and even more preferably 91 mol% or more, based on the total monomer units constituting the ionomer resin (Y), from the viewpoint of improving the impact resistance of the ionomer resin granules and from the viewpoint of increasing the melting point and maintaining heat resistance, and is preferably 94 mol% or less, more preferably 93 mol% or less, and even more preferably 92.5% or less, from the viewpoint of improving the transparency of the ionomer resin granules (particularly the transparency during slow cooling). When the content of the ethylene unit (C) is above the lower limit, the mechanical properties and moldability can be improved, and when it is below the upper limit, the transparency can be improved.

[0023] In one embodiment of the present invention, the ionomer resin (Y) preferably further contains (meth)acrylic acid ester units (D) in addition to the (meth)acrylic acid units (A), the (meth)acrylic acid neutralization product units (B), and the ethylene units (C), from the viewpoint of obtaining higher transparency.

[0024] When the ionomer resin (Y) contains the (meth)acrylic acid ester unit (D), the content of the (meth)acrylic acid ester unit (D) in the ionomer resin (Y) is not particularly limited. In one embodiment of the present invention, the content of the (meth)acrylic acid ester unit (D) in the ionomer resin (Y) is preferably more than 0 mol%, more preferably 0.01 mol% or more, even more preferably 0.05 mol% or more, particularly preferably 0.08 mol% or more, and is preferably 1.0 mol% or less, more preferably 0.7 mol% or less, and even more preferably 0.5 mol% or less, based on the total monomer units constituting the ionomer resin (Y). When the content of the unit (D) is the above lower limit or more and the above upper limit or less, the transparency of the ionomer resin granules can be improved.

[0025] When the ionomer resin (Y) contains (meth)acrylic acid ester units (D), the content of the units (D) can be adjusted by the reactivity of the saponification reaction that converts the (meth)acrylic acid ester units (D) in the ethylene-(meth)acrylic acid ester copolymer into (meth)acrylic acid units (A) when the ionomer resin is produced from an ethylene-(meth)acrylic acid ester copolymer as a raw material by a method that includes a saponification reaction step and a demetallation reaction step of the copolymer.

[0026] When the ionomer resin (Y) contains (meth)acrylic acid ester units (D), the total content of the units (A), (B) and (D) is preferably more than 6 mol% and not more than 10 mol% based on the total monomer units constituting the ionomer resin (Y) from the viewpoint of improving transparency (particularly transparency during slow cooling). When the ionomer resin (Y) contains (meth)acrylic acid ester units (D), if the total content of the units (A), (B) and (D) is not more than the above upper limit, the increase in melt viscosity during molding of the ionomer resin granules can be suppressed, thereby improving the molding processability of the ionomer resin granules. In addition, if the total content is greater than the lower limit, the transparency of the ionomer resin granules, particularly transparency during slow cooling, can be improved.

[0027] In the case where the ionomer resin (Y) contains the (meth)acrylic acid ester unit (D), the total content of the unit (A), the unit (B) and the unit (D) is preferably more than 6 mol %, more preferably 6.5 mol % or more, even more preferably 7.0 mol % or more, and particularly preferably 7.5 mol % or more, from the viewpoint of improving transparency (particularly transparency during slow cooling) and adhesion to a substrate, and is preferably 10 mol % or less, more preferably 9.9 mol % or less, and even more preferably 9.5 mol % or less, from the viewpoint of moldability.

[0028] The total content of the units (A), (B) and (D) can be adjusted by the raw material of the ionomer resin (Y). Specifically, it can be adjusted by the amount of (meth)acrylic acid ester modification of the ethylene-(meth)acrylic acid ester copolymer, which is the raw material of the ionomer resin (Y).

[0029] Examples of monomers constituting the (meth)acrylic acid ester unit (D) include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, t-butyl (meth)acrylate, amyl (meth)acrylate, isoamyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, pentadecyl (meth)acrylate, dodecyl (meth)acrylate, isobornyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, glycidyl (meth)acrylate, and allyl (meth)acrylate. Among these, from the viewpoint of transparency or heat resistance, preferred monomers are methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, and t-butyl (meth)acrylate, more preferred monomers are methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, and isobutyl (meth)acrylate, further preferred monomers are methyl (meth)acrylate, n-butyl (meth)acrylate, and isobutyl (meth)acrylate, and particularly preferred monomer is methyl (meth)acrylate. These (meth)acrylic acid esters may be used alone or in combination of two or more.

[0030] In one embodiment of the present invention, the ionomer resin (Y) may contain other monomer units other than the (meth)acrylic acid unit (A), the (meth)acrylic acid neutralized unit (B), and the ethylene unit (C), and the (meth)acrylic acid ester unit (D) that may be included. Examples of the other monomer units include carboxylic acid units (A1) other than the (meth)acrylic acid unit, and carboxylic acid neutralized units (B1) other than the (meth)acrylic acid neutralized unit. Examples of the monomers constituting the carboxylic acid units (A1) include itaconic acid, maleic anhydride, monomethyl maleate, monoethyl maleate, and the like, and preferably monomethyl maleate and monoethyl maleate. Examples of the monomers constituting the carboxylic acid neutralized unit (B1) include neutralized units of the carboxylic acid units (A1). Note that the carboxylic acid neutralized product is a product in which the hydrogen ion of the carboxylic acid is replaced with a metal ion. Examples of the metal ion include the same metal ions as those in the above-mentioned (meth)acrylic acid neutralization unit (B), and the metal ions may be one type alone or two or more types in combination. These other monomer units may be used alone or in combination of two or more.

[0031] When the ionomer resin (Y) contains the other monomer units, the total content of the other monomer units, for example, the total content of (A1) and (B1), may be appropriately selected within a range that does not impair the effects of the present invention, and is, for example, preferably 5 mol % or less, more preferably 3 mol % or less, even more preferably 1 mol % or less, and is also preferably 0.01 mol % or more, more preferably 0.1 mol % or more, based on all monomer units constituting the ionomer resin (Y).

[0032] The contents of the (meth)acrylic acid unit (A), the (meth)acrylic acid neutralized unit (B), and the ethylene unit (C), as well as the (meth)acrylic acid ester unit (D) and other monomer units (e.g., unit (A1) and unit (B1)) in the ionomer resin (Y) of the present invention can be determined by first identifying the monomer units in the ionomer resin (Y) by pyrolysis gas chromatography, and then using nuclear magnetic resonance spectroscopy (NMR) and elemental analysis. In addition, since the contents of the monomer units in the ionomer resin granules obtained by the production method of the present invention correspond to the contents of the monomer units in the ionomer resin (Y), the contents of the monomer units in the ionomer resin (Y) may be determined by analyzing the obtained ionomer resin granules instead of the ionomer resin (Y), and more specifically, the contents of the monomer units in the ionomer resin (Y) may be determined by the method described in the Examples. In addition, the contents of the monomer units may be determined by a method combining the above analysis with IR and / or Raman analysis. Prior to these analyses, it is preferable to remove components other than the ionomer resin (Y) or the obtained ionomer resin granules by reprecipitation or Soxhlet extraction.

[0033] (Method of producing ionomer resin (Y)) The method for producing the ionomer resin (Y) is not particularly limited, and examples thereof include the EMMA saponification method, specifically a method in which an ethylene-(meth)acrylic acid ester copolymer (X) is used as a raw material and all or a part of the (meth)acrylic acid ester units in the copolymer are converted into (meth)acrylic acid units and (meth)acrylic acid neutralized product units. Examples of the method for converting all or a part of the (meth)acrylic acid ester units into (meth)acrylic acid units and (meth)acrylic acid neutralized product units include a method in which an ethylene-(meth)acrylic acid ester copolymer (X) is saponified with an alkali to convert all or a part of the (meth)acrylic acid ester units into (meth)acrylic acid neutralized product units to obtain an ethylene-(meth)acrylic acid neutralized product copolymer or an ethylene-(meth)acrylic acid ester-(meth)acrylic acid neutralized product copolymer, and then a part of the (meth)acrylic acid neutralized product units in the obtained copolymer are demetalized with an acid to convert them into (meth)acrylic acid units (hereinafter also referred to as method (1)). As a method other than the method (1), there may be mentioned a method (hereinafter also referred to as method (2)) in which all of the (meth)acrylic acid neutralization units in an ethylene-(meth)acrylic acid neutralization copolymer or an ethylene-(meth)acrylic acid ester-(meth)acrylic acid neutralization copolymer obtained by the saponification in the above method (1) are demetalized with an acid to convert them into (meth)acrylic acid units to obtain an ethylene-(meth)acrylic acid copolymer or an ethylene-(meth)acrylic acid ester-(meth)acrylic acid copolymer, and then a part of the (meth)acrylic acid units in the obtained copolymer are neutralized with a metal ion. Of the above methods (1) and (2), it is preferable to produce the ionomer resin (Y) by the method (1), from the viewpoint of improving the production efficiency of the ionomer resin by reducing the number of reactions.

[0034] Examples of monomers constituting the (meth)acrylic acid ester unit of the ethylene-(meth)acrylic acid ester copolymer (X) include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, t-butyl (meth)acrylate, amyl (meth)acrylate, isoamyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, pentadecyl (meth)acrylate, dodecyl (meth)acrylate, isobornyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, glycidyl (meth)acrylate, and allyl (meth)acrylate. Among these, preferred monomers are methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, and t-butyl (meth)acrylate, more preferred monomers are methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, and isobutyl (meth)acrylate, further preferred monomers are methyl (meth)acrylate, n-butyl (meth)acrylate, and isobutyl (meth)acrylate, and particularly preferred monomers are methyl (meth)acrylate, n-butyl (meth)acrylate, and isobutyl (meth)acrylate, and particularly preferred is methyl (meth)acrylate. These (meth)acrylic acid esters may be used alone or in combination of two or more.

[0035] Specific examples of the ethylene-(meth)acrylic acid ester copolymer (X) include ethylene-methyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-ethyl methacrylate copolymer, ethylene-n-propyl acrylate copolymer, ethylene-n-propyl methacrylate copolymer, ethylene-isopropyl acrylate copolymer, ethylene-isopropyl methacrylate copolymer, ethylene-n-butyl acrylate copolymer, ethylene-n-butyl methacrylate copolymer, ethylene-sec-butyl acrylate copolymer, and ethylene-sec-butyl methacrylate copolymer. As these copolymers, commercially available products may be used, or those synthesized by the high-temperature, high-pressure radical polymerization method described in US2013 / 0274424, JP2006-233059, or JP2007-84743 may be used. Examples of the commercially available products include "Acryft" (registered trademark) WD301F and WK307 manufactured by Sumitomo Chemical Co., Ltd., "Rexpearl" (registered trademark) A4250 manufactured by Japan Polyethylene Corporation, and NUC-6070 manufactured by NUC Corporation.

[0036] The content of the (meth)acrylic acid ester unit in the ethylene-(meth)acrylic acid ester copolymer (X) is preferably 6 mol% or more, more preferably 6.5 mol% or more, even more preferably 7 mol% or more, particularly preferably 7.5 mol% or more, and also preferably 10 mol% or less, more preferably 9.9 mol% or less, and even more preferably 9.5 mol% or less. The total content of the (meth)acrylic acid unit (A) and the (meth)acrylic acid neutralized unit (B) in the obtained ionomer resin (Y) and the ionomer resin granules, and the (meth)acrylic acid ester unit (D) when contained, can be adjusted depending on the content of the (meth)acrylic acid ester unit in the copolymer (X). Therefore, when the content of the (meth)acrylic acid ester unit in the copolymer (X) is the above lower limit or more, the transparency of the obtained ionomer resin granules, especially the transparency during slow cooling, can be improved, and when the content is the above upper limit or less, the molding processability of the obtained ionomer resin can be improved. The content can be adjusted by the copolymerization ratio of ethylene and (meth)acrylic acid ester. The content can be determined by pyrolysis gas chromatography, nuclear magnetic resonance spectroscopy (NMR) and elemental analysis, as well as the contents of (meth)acrylic acid unit (A), (meth)acrylic acid neutralized unit (B), ethylene unit (C), and (meth)acrylic acid ester unit (D) and other monomer units (e.g. unit (A1) and unit (B1)) in the above-mentioned ionomer resin (Y).

[0037] In one embodiment of the present invention, the melt flow rate (MFR) of the ethylene-(meth)acrylic acid ester copolymer (X) measured in accordance with JIS K7210-1:2014 under conditions of 190 ° C. and 2.16 kg is preferably 1 g / 10 min or more, more preferably 5 g / 10 min or more, even more preferably 10 g / 10 min or more, even more preferably 50 g / 10 min or more, particularly preferably 100 g / 10 min or more, and preferably 400 g / 10 min or less, more preferably 350 g / 10 min or less, even more preferably 300 g / 10 min or less, and even more preferably 250 g / 10 min or less. When the MFR of the ethylene-(meth)acrylic acid ester copolymer (X) is the above lower limit or more and the above upper limit or less, the molding processability of the obtained ionomer resin granules can be improved. In addition, the strength of the obtained ionomer resin granules can be improved. The MFR of the ethylene-(meth)acrylic acid ester copolymer (X) can be adjusted by the degree of polymerization and the content of the (meth)acrylic acid ester unit. The MFR can be measured, for example, by the method described in the Examples.

[0038] The weight average molecular weight of the ethylene-(meth)acrylic acid ester copolymer (X) is preferably 15,000 g / mol or more, more preferably 20,000 g / mol or more, even more preferably 30,000 g / mol or more, and preferably 200,000 g / mol or less, more preferably 100,000 g / mol or less, from the viewpoint of improving the moldability and strength of the obtained ionomer resin granules. From the same viewpoint, the number average molecular weight of the ethylene-(meth)acrylic acid ester copolymer (X) is preferably 5,000 g / mol or more, more preferably 10,000 g / mol or more, even more preferably 15,000 g / mol or more, and preferably 100,000 g / mol or less, more preferably 50,000 g / mol or less. The weight average molecular weight and number average molecular weight can be adjusted by the amount of polymerization initiator and / or chain transfer agent during polymerization. The molecular weights (weight average molecular weight and number average molecular weight) of these ethylene-(meth)acrylic acid ester copolymers (X) were measured using a column (TSKgel GMH HR Using three -H(20)HT columns in series and 1,2,4-trichlorobenzene as a solvent, the measurement can be performed in polystyrene equivalent at a column temperature of 140°C.

[0039] The branching degree per 1000 carbons of the ethylene-(meth)acrylic acid ester copolymer (X) is not particularly limited, and is preferably 5 to 30, and more preferably 6 to 20. The branching degree can be adjusted by the polymerization temperature when polymerizing the copolymer (X). The branching degree per 1000 carbons can be adjusted by dissolving the ethylene-(meth)acrylic acid ester copolymer (X) in deuterated orthodichlorobenzene, 13 It can be measured by the inverse gate decoupling method of C-NMR.

[0040] Examples of the alkali used in the saponification reaction in the above methods (1) and (2) include strong bases such as sodium hydroxide, potassium hydroxide, calcium hydroxide, etc. From the viewpoint of solubility in the solvent used in the saponification reaction or economic efficiency, sodium hydroxide and potassium hydroxide are preferred.

[0041] Examples of the solvent used in the above saponification reaction include ethers such as tetrahydrofuran and dioxane, halogen-containing solvents such as chloroform and dichlorobenzene, ketones having 6 or more carbon atoms such as methyl butyl ketone, mixed solvents of hydrocarbon compounds and alcohols such as methanol, ethanol, 1-propanol, 2-propanol, and 1-butanol, aromatic compounds such as benzene, toluene, xylene, and ethylbenzene, mixed solvents of aromatic compounds and alcohols, etc. These solvents may be used alone or in combination of two or more. Among these, from the viewpoint of the solubility of the resin before and after the saponification reaction, preferred solvents are a mixed solvent of a hydrocarbon compound and an alcohol, and a mixed solvent of an aromatic compound and an alcohol, and more preferred solvents are a mixed solvent of an aromatic compound such as toluene and an alcohol such as methanol. The ratio of the hydrocarbon compound or aromatic compound to the alcohol in the mixed solvent may be appropriately selected depending on the type of each solvent used, and for example, the mass ratio of the hydrocarbon compound or aromatic compound to the alcohol (hydrocarbon compound or aromatic compound / alcohol) may be 50 / 50 to 90 / 10.

[0042] The temperature at which the saponification reaction is carried out is, from the viewpoints of the reactivity and the solubility of the ethylene-(meth)acrylic acid ester copolymer (X), preferably 50° C. or higher, more preferably 60° C. or higher, further preferably 70° C. or higher, and particularly preferably 80° C. or higher. The upper limit of the temperature is not particularly limited as long as it is lower than the temperature at which the ethylene-(meth)acrylic acid ester copolymer (X) decomposes, and is, for example, 300° C. or lower.

[0043] The saponification reaction may be carried out in air or in an inert gas such as nitrogen gas, argon gas, etc. The saponification reaction may be carried out under normal pressure, elevated pressure, or reduced pressure, and is preferably carried out under elevated pressure.

[0044] Examples of the acid used in the demetallation in the above methods (1) and (2) include strong acids such as hydrochloric acid, nitric acid, sulfuric acid, toluenesulfonic acid, etc. From the viewpoint of ease of removal of salts after demetallation, inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid, etc. As the solvent used in the above demetallation, the same solvent as that used in the above saponification reaction can be selected.

[0045] The temperature at which the above-mentioned demetallization is carried out is, from the viewpoint of resin solubility and the ability to reduce the viscosity of the reaction liquid, preferably 20°C or higher, more preferably 30°C or higher, even more preferably 40°C or higher, and is preferably 100°C or lower, more preferably 80°C or lower, even more preferably 70°C or lower, and even more preferably 60°C or lower.

[0046] The demetallation may be carried out in air or in an inert gas such as nitrogen gas, argon gas, etc., similarly to the saponification reaction. The saponification reaction may be carried out under normal pressure, under pressure, or under reduced pressure, and is preferably carried out under pressure.

[0047] In the above method (2), the neutralizing agent used when neutralizing a part of the (meth)acrylic acid unit to convert it into a (meth)acrylic acid neutralized product unit is not particularly limited as long as it is an ionic compound containing a metal ion. Examples of the metal ion include alkali metal ions such as lithium, potassium, and sodium, alkaline earth metal ions such as magnesium and calcium, transition metal ions such as zinc, nickel, iron, and titanium, and aluminum ions. For example, when the metal ion is a sodium ion, examples of the neutralizing agent include sodium hydroxide, sodium acetate, and sodium hydrogen carbonate. In addition, polymers such as ionomer resins containing sodium (meth)acrylate units can also be used as neutralizing agents.

[0048] In one embodiment of the present invention, the degree of saponification in the ionomer resin (Y) obtained by the above EMMA saponification method, i.e., the ratio of the total of the (meth)acrylic acid unit (A) and the (meth)acrylic acid neutralized product unit (B) to the total of the (meth)acrylic acid unit (A), the (meth)acrylic acid neutralized product unit (B) and the (meth)acrylic acid ester unit (D), may be preferably 85 to 100%, more preferably 87 to 99.5%, and even more preferably 90 to 99%, from the viewpoint of improving adhesion to glass. Also, in one embodiment of the present invention, the degree of neutralization of the ionomer resin (Y) obtained by the above EMMA saponification method, i.e., the ratio of the (meth)acrylic acid neutralized product unit (B) to the total of the (meth)acrylic acid unit (A) and the (meth)acrylic acid neutralized product unit (B), is preferably 0 to 55%, more preferably 10 to 40%, and even more preferably 15 to 30%, from the viewpoint of improving moldability into a resin sheet and transparency of the obtained resin sheet during annealing.

[0049] In one embodiment of the present invention, the ionomer resin (Y) contains a salt generated by neutralization reaction between an alkali and an acid during the process of producing the ionomer resin (Y) in an amount of, for example, 100,000 mg / kg or more and 500,000 mg / kg or less. The salt generated during the process of producing the ionomer resin (Y) is a salt consisting of the strong base described above as the alkali used in the saponification reaction and the strong acid described above as the acid used in the demetalization reaction. The salt may be one type alone or a combination of two or more types. The content of the salt in the ionomer resin (Y) can be measured using an ion chromatograph. The theoretical content of the salt, which can be calculated by a known method from the amount of the raw material resin, etc., can be used as the content of the salt in the ionomer resin (Y).

[0050] (solvent) The solvent in step (I) is not particularly limited as long as it is a solvent capable of dissolving the ionomer resin (Y), and examples thereof include ethers such as tetrahydrofuran, dioxane, etc.; halogen-containing solvents such as chloroform, dichlorobenzene, etc.; ketones having 6 or more carbon atoms such as methyl butyl ketone, etc.; nitrogen-containing compounds such as pyridine, N-methyl-2-pyrrolidone, dimethylformamide, etc.; hydrocarbon compounds such as n-heptane, n-hexane, cyclohexane, etc.; alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, etc.; aromatic compounds such as benzene, toluene, xylene, ethylbenzene, etc.; and mixed solvents thereof. Among these, from the viewpoint of the solubility of the ionomer resin (Y), a mixed solvent of an aromatic compound such as toluene and an alcohol such as methanol is preferred. The ratio of the aromatic compound to the alcohol in the mixed solvent may be appropriately selected depending on the type of each solvent used, and for example, the mass ratio of the aromatic compound to the alcohol (aromatic compound / alcohol) may be 50 / 50 to 90 / 10, preferably 60 / 40 to 85 / 15, and more preferably 65 / 35 to 80 / 20.

[0051] These solvents in step (I) may contain water within a range in which the ionomer resin (Y) can be dissolved. In one embodiment of the present invention, the content of water is, from the viewpoint of the solubility of the ionomer resin (Y), preferably 30 mass% or less, more preferably 20 mass% or less, even more preferably 15 mass% or less, particularly preferably 14 mass% or less, and is preferably 0 mass% or more, more preferably 0.1 mass% or more, and even more preferably 1 mass% or more, based on the total mass of the solvent.

[0052] (Sol-like mixture containing ionomer resin (Y) and solvent) The sol-like mixture containing the ionomer resin (Y) and a solvent in step (I) (hereinafter, simply referred to as "sol-like mixture") can be prepared by mixing the ionomer resin (Y) with a solvent. In one embodiment of the present invention, a reaction solution of the ionomer resin (Y) obtained by producing an ionomer resin by the above-mentioned method (1) or (2), or a mixture obtained by further adding a solvent to the reaction solution, may be used as the sol-like mixture containing the ionomer resin (Y) and a solvent.

[0053] The sol-like mixture has fluidity. The sol-like mixture is a liquid mixture in which the ionomer resin (Y) and the solvent, or the reaction liquid (sol-like mixture) and the solvent are not separated, and the ionomer resin (Y) is dissolved or dispersed in the solvent. In one embodiment of the present invention, the viscosity of the sol mixture at 50° C. is not particularly limited, but from the viewpoint of handleability, is, for example, preferably 20 Pa s or less, more preferably 10 Pa s or less, and further preferably 6 Pa s or less. The viscometer used to measure the viscosity of the sol mixture is not particularly limited, but for example, an E-type viscometer or a B-type viscometer can be suitably used.

[0054] In one embodiment of the present invention, the temperature of the sol mixture in step (I) (the sol mixture before slow cooling) is preferably 50°C or higher, more preferably 52°C or higher, even more preferably 54°C or higher, and particularly preferably 56°C or higher. When the temperature of the sol mixture is equal to or higher than the lower limit, the fluidity of the sol mixture can be increased, and a more uniform sol mixture can be obtained. In addition, the temperature of the sol mixture is preferably 68°C or lower, more preferably 65°C or lower, even more preferably 63°C or lower, and particularly preferably 60°C or lower. When the temperature of the sol mixture is equal to or lower than the upper limit, a porous granular ionomer resin gel or ionomer resin granules having excellent salt removal properties can be obtained. The temperature of the sol mixture can be measured by a known method.

[0055] In one embodiment of the present invention, the concentration of the ionomer resin (Y) in the sol-like mixture is preferably 18.5% by mass or less, more preferably 18% by mass or less, even more preferably 16% by mass or less, even more preferably 14% by mass or less, and particularly preferably 12% by mass or less, based on the mass of the sol-like mixture. The lower the concentration of the ionomer resin (Y) in the sol-like mixture, the larger the median diameter of the resulting granules. Therefore, when the concentration is below the upper limit, the desired median diameter can be obtained, and as a result, the removal of salt can be improved, and an ionomer resin granule with excellent transparency can be obtained. In addition, the concentration of the ionomer resin (Y) in the sol-like mixture is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, and particularly preferably 8% by mass or more. When the concentration is above the lower limit, the strength of the resulting gel can be increased, and the handling property can be improved.

[0056] (Slow cooling and gelation) By slowly cooling the sol mixture, the ionomer resin (Y) can be gelled. The reason is not clear and is not limited to the following reasons, but it is thought that the solubility of the ionomer resin in the solvent gradually decreases during the slow cooling process, forming a gel skeleton, and at that time, the solvent remains suitably in the gel skeleton and / or is suitably incorporated into the gel skeleton. When the sol mixture is cooled or rapidly cooled rather than slowly cooled, for example, when the sol mixture is discharged or extruded into a refrigerant (e.g., into a poor solvent) at 5°C or less, a gel of the ionomer resin cannot be obtained. Moreover, by slowly cooling the sol-like mixture, the median diameter of the ionomer resin gel particles and the ionomer resin particles can be adjusted to a suitable range.

[0057] The method for slowly cooling the sol mixture is not particularly limited as long as it can gel the ionomer resin (Y). The sol mixture can be slowly cooled by allowing the sol mixture in the container to cool or gradually cooling it, or by allowing the sol mixture taken out, discharged or extruded from the container to cool or gradually cooling it. Here, allowing the container or the sol-like mixture to cool means leaving the container or the sol-like mixture in a gas atmosphere at a predetermined temperature range (e.g., -10°C to 50°C, preferably 0°C to 40°C, more preferably 5°C to 30°C) for a predetermined time (e.g., 1 second to 60 minutes, preferably 1 second to 30 minutes, more preferably 1 second to 10 minutes, more preferably 1 second to 5 minutes, even more preferably 1 second to 1 minute, and even more preferably 1 second to 50 seconds). The gas atmosphere may be an air or nitrogen atmosphere, and is usually air. The air may be dry air or humidified air. For the cooling, a known cooling means such as a gas flow (for example, an air flow) can be used. The flow rate of the gas in the gas flow is preferably 1 to 300 m / min, more preferably 5 to 100 m / min. When the sol mixture in the container is slowly cooled, it may be cooled slowly while stirring with a stirring means such as a stirring bar or a magnetic stirrer.

[0058] In one embodiment of the present invention, the temperature difference between the temperature of the sol mixture before gradual cooling and the temperature of the gas atmosphere when gradual cooling is performed by standing to cool, or the temperature of the gas flow when gradual cooling is performed by cooling, is preferably 5°C or more, more preferably 10°C or more, from the viewpoint of obtaining a gradual cooling rate suitable for gelation, and is preferably 100°C or less, more preferably 70°C or less, and even more preferably 50°C or less (e.g., 40°C or less, 30°C or less).

[0059] In one embodiment of the present invention, the sol mixture is slowly cooled to a temperature of preferably 40° C. or less, more preferably 38° C. or less, and particularly preferably 35° C. or less. By slowly cooling the sol mixture to a temperature equal to or less than the upper limit, the solvent contained in the sol mixture can preferably remain in and / or be incorporated into the gel skeleton, and as a result, the desired gel can be obtained. The lower limit of the temperature for slowly cooling the sol mixture is not particularly limited, but from the viewpoint of productivity, it is preferably 0° C. or higher, more preferably 10° C. or higher.

[0060] In a preferred embodiment of the present invention, a poor solvent is not used as a refrigerant for slow cooling. By not using a poor solvent in the process of forming a gel skeleton of an ionomer resin by slow cooling, it is believed that the solvent contained in the sol-like mixture can be suitably left in and / or suitably incorporated into the gel skeleton, and as a result, an ionomer resin gel and ionomer resin granules having a desired median diameter can be obtained.

[0061] In one embodiment of the present invention, after the gel skeleton of the ionomer resin is formed, i.e., after gelation, a poor solvent may be used as a refrigerant for cooling the obtained gel. The method of using a poor solvent as a refrigerant is not particularly limited, and examples thereof include a method of immersing the gel in the poor solvent or pouring the poor solvent onto the gel. The temperature of the poor solvent when used as a refrigerant is not particularly limited as long as it can cool the gel, i.e., is lower than the temperature of the gel. In one embodiment of the present invention, the temperature of the poor solvent when used as a refrigerant is preferably less than 40° C., more preferably 35° C. or less, even more preferably 30° C. or less, and particularly preferably 20° C. or less, from the viewpoint of increasing the cooling rate. The temperature may be 0° C. or more. The poor solvent can also remove at least a portion of the salt in the ionomer resin gel while cooling the ionomer resin gel.

[0062] The poor solvent is not particularly limited as long as it can cool the ionomer resin gel without dissolving it. From the viewpoint of being able to dissolve and remove salts in the ionomer resin gel, water, alcohol, or a mixed solvent thereof is preferred. Examples of alcohol include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, etc., and preferably methanol or ethanol, more preferably methanol. The alcohol may be used alone or in combination of two or more kinds. Among these poor solvents, water is preferred.

[0063] When the ionomer resin gel is cooled using a poor solvent after gelation, the shape, particle size, median pore size, and porosity of the ionomer resin gel change little or not before and after cooling. The pores in the ionomer resin gel are filled with the solvent, and no air exists in the pores. The porosity of the ionomer resin gel described in this specification refers to the porosity of the ionomer resin gel when it is assumed that the solvent does not exist in the pores.

[0064] By slowly cooling the sol mixture, gelation occurs. The fluidity of the sol mixture decreases due to gelation. The temperature at which gelation occurs varies depending on the type and ratio of the constituent units in the ionomer resin (Y), the molecular weight, the concentration of the ionomer resin (Y) in the sol mixture, the composition of the solvent contained in the sol mixture, and the like. Gelation can be determined, for example, by checking that 90% or more by volume of the gel does not flow for one minute or more at that temperature when a container containing the gel is tilted 90°.

[0065] In step (I), the porous ionomer resin gel obtained by the gelation may be optionally pulverized. In the present invention, pulverization means reduction in particle size. That is, pulverization in the present invention includes not only pulverization, crushing, or cutting of the ionomer resin gel taken out, discharged, or extruded from a container using a device such as a crusher, pelletizer, or cutter, but also division or rupture of the ionomer resin gel by stirring during slow cooling or by taking it out of a container. For example, if the desired granular ionomer resin gel is already obtained during the gelation process, the pulverization step does not need to be carried out. Examples of the crusher include medium crushers such as a roll crusher, a cutting mill, and a ring mill, and fine crushers such as a roller mill, a pin mill, a rotary mill, a vibration mill, and a planetary mill.

[0066] (Porous granular ionomer resin gel) The gelation and optional crushing in step (I) results in a porous granular ionomer resin gel, which has poor flowability and does not flow even when tilted, for example, at an angle of up to 90° relative to the horizontal. The porous granular ionomer resin gel contains an ionomer resin (Y) and a solvent. The pores in the ionomer resin gel are filled with the solvent. In one embodiment of the present invention, it is presumed that in the porous granular ionomer resin gel, the ionomer resin crystallizes and undergoes phase separation from the solvent during slow cooling, forming a plurality of pores. If the cooling rate is fast, it is difficult to obtain a porous ionomer resin gel that does not undergo sufficient phase separation and can wash away salts. The solid content concentration of the porous granular ionomer resin gel obtained by the present invention is preferably in the same range as the concentration of the ionomer resin (Y) in the sol-like mixture before gelation.

[0067] In one embodiment of the present invention, the median diameter of pores in the granular ionomer resin gel obtained in step (I) is preferably greater than 1.2 μm, more preferably 1.5 μm or more, even more preferably 1.8 μm or more, and particularly preferably 2.0 μm or more, from the viewpoint of improving salt removal and obtaining ionomer resin granules having excellent transparency. Also, the median diameter of the pores is preferably 50 μm or less, more preferably 30 μm or less, even more preferably 10 μm or less, and particularly preferably 5.0 μm or less, from the viewpoint of obtaining ionomer resin granules having excellent strength.

[0068] The median diameter of the porous granular ionomer resin gel obtained in step (I) can be adjusted by the concentration of the ionomer resin (Y) in the sol-like mixture, the type of solvent, the ratio of the solvents when two or more types of solvents are used, the temperature, etc. For example, the median diameter can be reduced by increasing the concentration of the ionomer resin (Y) in the sol-like mixture or decreasing the proportion of the poor solvent, and the median diameter can be increased by decreasing the concentration of the ionomer resin (Y) in the sol-like mixture or increasing the proportion of the poor solvent.

[0069] In one embodiment of the present invention, the porosity of the porous granular ionomer resin gel obtained in step (I) is preferably 60% or more, more preferably 62% or more, even more preferably 64% or more, even more preferably 68% or more, and particularly preferably 70% or more. When the porosity is equal to or more than the above lower limit, the salt removability can be improved, and therefore, an ionomer resin granule having excellent transparency can be obtained. In addition, the porosity is preferably 90% or less, more preferably 85% or less, even more preferably 80% or less, and particularly preferably 75% or less. When the porosity is equal to or less than the above upper limit, an ionomer resin granule having excellent strength can be obtained. In this embodiment, from the viewpoint of improving salt removability and obtaining ionomer resin granules having excellent transparency, the porous granular ionomer resin gel has a value obtained by dividing the porosity (%) by the median pore diameter (μm) [porosity (%) / median pore diameter (μm)] of preferably 1 or more, more preferably 2 or more, even more preferably 3 or more, and particularly preferably 5 or more. From the viewpoint of obtaining ionomer resin granules having high strength, the value is preferably 50 or less, more preferably 40 or less, even more preferably 30 or less, and particularly preferably 20 or less.

[0070] The porosity of the porous granular ionomer resin gel obtained in step (I) can be adjusted by the concentration of the ionomer resin (Y) in the sol-like mixture, the temperature of the sol-like mixture before annealing, the discharge or extrusion rate when the sol-like mixture is discharged or extruded, the annealing rate, the particle size of the granular ionomer resin gel, etc. For example, the porosity can be reduced by increasing the concentration of the ionomer resin (Y) in the sol-like mixture, slowing the annealing rate, or increasing the particle size of the granular ionomer resin gel, while the porosity can be increased by decreasing the concentration of the sol-like mixture, increasing the annealing rate, or decreasing the particle size of the granular ionomer resin gel.

[0071] The porosity and median pore diameter can be measured by mercury intrusion using a pore distribution measuring device, for example, by the method described in the Examples. Note that the porosity and median pore diameter of the granular ionomer resin gel obtained in step (I) are hardly or not changed by the solvent removal step described below, and therefore the porosity and median pore diameter of the obtained ionomer resin granules can also be the porosity and median pore diameter of the granular ionomer resin gel obtained in step (I). The same applies to the value obtained by dividing the porosity (%) by the median pore diameter (μm).

[0072] In one embodiment of the present invention, the porous granular ionomer resin gel obtained in step (I) preferably has a pellet shape such as a sphere, cylinder, elliptical cylinder, polygonal cylinder, or rugby ball shape, or an irregular shape, from the viewpoints of productivity and salt removability. In one embodiment of the present invention, the particle size of the granular ionomer resin gel is preferably 0.01 mm or more, more preferably 0.1 mm or more, and even more preferably 1 mm or more, from the viewpoint of ease of handling. Also, the particle size of the granular ionomer resin gel is preferably 8 mm or less, more preferably 6 mm or less, and even more preferably 5 mm or less, from the viewpoint of obtaining higher salt removal performance. The particle size of the granular ionomer resin gel can be measured by the same method as the particle size of the ionomer resin granules described below. Furthermore, since the shape and particle size of the porous granular ionomer resin gel obtained in step (I) change little or not at all due to the solvent removal step described below, the shape and particle size of the obtained ionomer resin granules can also be the shape and particle size of the granular ionomer resin gel obtained in step (I).

[0073] <Process (II)> Step (II) is a step of removing the solvent from the porous granular ionomer resin gel to obtain ionomer resin granules.

[0074] The method for removing the solvent is not particularly limited, and examples thereof include a method of treating the granular ionomer resin gel at a temperature of 40 to 80°C under an inert atmosphere such as nitrogen while optionally applying a reduced pressure, and a method of washing the granular ionomer resin gel with a washing liquid.

[0075] In one embodiment of the present invention, the method of the present invention preferably includes washing the porous granular ionomer resin gel obtained in step (I) or the ionomer resin granules obtained in step (II) with a washing liquid. By washing the porous granular ionomer resin gel or the ionomer resin granules with a washing liquid, the salt content in the obtained ionomer resin granules can be reduced, and therefore, an ionomer resin granule having excellent transparency, particularly transparency when absorbing water, can be obtained.

[0076] From the viewpoint of being able to rapidly remove the solvent from the granular ionomer resin gel and being able to simultaneously remove the solvent and salt from the granular ionomer resin gel, it is preferable that the removal of the solvent from the porous granular ionomer resin gel in step (II) is carried out by washing the porous granular ionomer resin gel with a washing liquid. Thus, in one embodiment of the present invention, the method of the present invention includes, as step (II), washing the porous granular ionomer resin gel with a washing liquid, whereby the solvent is removed from the porous granular ionomer resin gel to obtain ionomer resin granules. When the removal of the solvent is carried out by treatment at the above temperature, the salt can be removed from the ionomer resin granules by washing the ionomer resin granules after the removal of the solvent with a washing liquid.Accordingly, in one embodiment of the present invention, the process of the present invention comprises washing the ionomer resin granules with a washing liquid after steps (I) and (II).

[0077] The cleaning liquid is not particularly limited as long as it is a solvent that does not dissolve the granular ionomer resin gel or ionomer resin granules, can dissolve the salt, and can preferably remove the solvent from the granular ionomer resin gel or ionomer resin granules. Examples of preferred cleaning liquids include alcohols such as methanol, ethanol, 1-propanol, and 2-isopropanol; water; ketones such as acetone and methyl ethyl ketone; esters such as methyl acetate and ethyl acetate; and ethers such as dimethyl ether, diethyl ether, and tetrahydrofuran. These may be used alone or in combination of two or more.

[0078] Among these cleaning liquids, alcohol, water, and a mixture thereof are preferred from the viewpoint of being able to remove the solvent from the granular ionomer resin gel, having high solubility of salt, and being able to remove the salt contained in the granular ionomer resin gel or ionomer resin granules, and a mixture of water and alcohol is more preferred. When the cleaning liquid is a mixture of water and alcohol, the solubility of salt is high, and the specific gravity of the cleaning liquid can be made lower than that of the granular ionomer resin gel or ionomer resin granules, so that the contact area between the cleaning liquid and the granular ionomer resin gel or ionomer resin granules can be increased, and the removal of salt can be improved. In addition, impurities such as organic compounds contained in the granular ionomer resin gel or ionomer resin granules can be removed, and the ionomer resin granules obtained after washing can be easily dried. Preferred alcohols are methanol and ethanol, because they are easy to dry and have high compatibility with water, and more preferably methanol. The ratio of water to alcohol (water / alcohol (mass %)) in the mixed liquid of water and alcohol is preferably 20 / 80 to 80 / 20, and more preferably 30 / 70 to 70 / 30.

[0079] The method for washing the granular ionomer resin gel or ionomer resin granules with a washing liquid is not particularly limited, but for example, a method of mixing the granular ionomer resin gel or ionomer resin granules with a washing liquid and then draining the liquid can be mentioned. More specifically, a washing method can be mentioned in which the granular ionomer resin gel or ionomer resin granules are mixed with a washing liquid, the gel or granules are filtered out from the washing liquid (hereinafter also referred to as washing step (a)), the filtered gel or granules are then mixed with a new washing liquid, and the gel or granules are filtered out from the washing liquid (hereinafter also referred to as washing step (b)). From the viewpoint of being able to reduce the salt content contained in the granular ionomer resin gel or ionomer resin granules and obtain ionomer resin granules having excellent transparency, particularly transparency when absorbing water, and from the viewpoint of being able to improve the efficiency of the separation and purification process of the granular ionomer resin gel or ionomer resin granules, in the case of a batch process, washing of the granules is preferably carried out, for example, by carrying out one washing step (a) followed by one to eight washing steps (b), and the number of washing steps (b) following one washing step (a) is more preferably one to five times, and even more preferably one to three times.

[0080] The amount of the washing liquid used per washing step may be appropriately selected depending on the amount of granular material to be washed. For example, the amount of the washing liquid used per washing step is preferably 100 to 2000 parts by mass, more preferably 200 to 1000 parts by mass, and even more preferably 300 to 700 parts by mass, per 100 parts by mass of granular material on a dry basis.

[0081] The washed ionomer resin granules may be dried as necessary. The drying temperature is preferably not higher than the melting point of the ionomer resin granules, more preferably not higher than 80°C.

[0082] <Ionomer resin granules> Since the method of the present invention includes steps (I) and (II), it is possible to improve the removal efficiency of salts, and therefore the porous ionomer resin granules obtained by the method of the present invention have excellent transparency.

[0083] As described above, in one embodiment of the present invention, the ionomer resin (Y) contains salts generated by neutralization reaction between an alkali and an acid in the process of producing the ionomer resin (Y) in an amount of, for example, 100,000 mg / kg or more and 500,000 mg / kg or less. However, the ionomer resin granules obtained by the method of the present invention have excellent transparency because the salts generated in the process of producing the ionomer resin (Y) are sufficiently reduced.

[0084] In one embodiment of the present invention, the salt content in the ionomer resin granules is preferably 1000 mg / kg or less, more preferably 700 mg / kg or less, even more preferably 400 mg / kg or less, even more preferably 350 mg / kg or less, particularly preferably 300 mg / kg or less, and particularly preferably 250 mg / kg or less, from the viewpoint of improving the transparency of the ionomer resin granules, particularly the transparency when absorbing water, and therefore the lower limit is not particularly limited and may be 0 mg / kg or more, and may be preferably 1 mg / kg or more from the viewpoint of improving the thermal decomposition resistance of the ionomer resin granules. The salt content in the ionomer resin granules can be measured using an ion chromatograph, for example, by the method described in the Examples.

[0085] Examples of salts of strong acids and strong bases include lithium salts, sodium salts, potassium salts, rubidium salts, cesium salts, etc., and preferably include alkali metal salts such as lithium salts, sodium salts, and potassium salts; and alkaline earth metal salts such as beryllium salts, magnesium salts, calcium salts, strontium salts, and barium salts. From the viewpoint of improving the thermal decomposition resistance of the ionomer resin granules, preferred salts are sodium salts and potassium salts. More preferred examples of salts include salts consisting of at least one cation selected from the group consisting of sodium ions, potassium ions, magnesium ions, and calcium ions, and at least one anion selected from the group consisting of halogen ions, sulfate ions, nitrate ions, and sulfonate ions. From the viewpoint of improving the thermal decomposition resistance of the ionomer resin granules, preferred salts are salts consisting of at least one cation selected from the group consisting of sodium ions and potassium ions, and at least one anion selected from the group consisting of halogen ions, sulfate ions, and nitrate ions.

[0086] More specifically, examples of preferred salts of strong acids and strong bases include sodium chloride, potassium chloride, magnesium chloride, calcium chloride, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate, sodium nitrate, potassium nitrate, magnesium nitrate, calcium nitrate, sodium p-toluenesulfonate, potassium p-toluenesulfonate, magnesium p-toluenesulfonate, and calcium p-toluenesulfonate. From the viewpoint of improving transparency and heat resistance, more preferred are sodium chloride, potassium chloride, sodium sulfate, potassium sulfate, sodium nitrate, and potassium nitrate, and even more preferred are sodium chloride, sodium sulfate, and sodium nitrate.

[0087] The ionomer resin granules contain (meth)acrylic acid units (A), (meth)acrylic acid neutralized units (B) and ethylene units (C), and the total content of the units (A) and (B) is 6 to 10 mol% based on the total monomer units constituting the ionomer resin granules. In addition to the units (A), (B) and ethylene units (C), the ionomer resin granules may contain other monomer units such as (meth)acrylic acid ester units (D) and / or carboxylic acid units (A1) other than (meth)acrylic acid units and carboxylic acid neutralized units (B1) other than (meth)acrylic acid neutralized units. Examples of the units (A) and (B) in the ionomer resin granules, and the units (D) and other monomer units (A1) and (B1) optionally contained therein include the same units as those described above for the units (A), (B), (D), (A1) and (B1) contained in the ionomer resin (Y), and the preferred forms are also the same as those for the ionomer resin (Y). The contents of each unit in the ionomer resin granules, the total content of the units (A) and (B), and the total content of the units (A), (B) and (D) when the ionomer resin granules contain (meth)acrylic acid ester units (D), are also the same as those described above for the ionomer resin (Y), including the preferred forms.

[0088] The ionomer resin granules are preferably porous. The descriptions of the porosity, median pore diameter, shape and particle size of the ionomer resin granules are similarly applicable to the porosity, median pore diameter, shape and particle size of the granular ionomer resin gel obtained in step (I). The porosity, median pore diameter, shape and particle size of the ionomer resin granules are almost or completely unchanged from the porosity, median pore diameter, shape and particle size of the porous granular ionomer resin gel obtained in step (I), so the porosity, median pore diameter, shape and particle size of the porous granular ionomer resin gel obtained in step (I) can also be the porosity, median pore diameter, shape and particle size of the ionomer resin granules. The same applies to the value obtained by dividing the porosity (%) of the ionomer resin granules by the median pore diameter (μm).

[0089] In the present invention, when the ionomer resin granules have a cylindrical, elliptical, or polygonal pellet shape, the particle size of each ionomer resin granule is the average value ((Lx+Ly+Lz) / 3) of the X-axis length (Lx), Y-axis length (Ly), and Z-axis length (Lz) of the pellet-shaped granules, and the particle size is preferably the arithmetic average value of the average values ​​of the X-axis, Y-axis, and Z-axis lengths of at least 10 pellet-shaped granules. Here, the X-axis length (Lx) of the pellet-shaped granules is the height of the pellet-shaped granules, the Y-axis length (Ly) is the diameter or the longest part of the diagonal of the plane perpendicular to the X-axis (the bottom surface of the pellet-shaped granules), and the Z-axis length (Lz) is the diameter or the shortest part of the diagonal of the bottom surface of the pellet-shaped granules. In addition, when the base is triangular, the length of the Y axis (Ly) is the longest side of the base, and the length of the Z axis (Lz) is the length of the shortest side of the base. Therefore, for example, in the case of a pellet-shaped granular material having an elliptical cylinder, the particle size per particle is the average value of the height (Lx), major axis diameter (Ly) and minor axis diameter (Lz) of the elliptical cylinder ((height + major axis diameter + minor axis diameter) / 3). A conceptual diagram of the length of the X axis (Lx), the length of the Y axis (Ly) and the length of the Z axis (Lz) of the pellet-shaped granular material is shown in FIG. 1. The right diagram in FIG. 1 is a plan view of the pellet-shaped granular material shown in the left diagram in FIG. 1 as viewed from the X-axis direction. The particle size can be calculated by measuring the length of the X axis (Lx), the length of the Y axis (Ly) and the length of the Z axis (Lz) of each pellet-shaped granular material using a micrometer or the like, and can be obtained, for example, by the method described in the Examples. In the present invention, when the pellet-shaped granules are spherical, the particle size per particle is the diameter of the pellet-shaped granules, and the particle size is preferably the average value of the diameters of 10 or more pellet-shaped granules. In the present invention, when the pellet-shaped granules are rugby ball-shaped, the particle size per particle is preferably the average value of the major axis and minor axis of the pellet-shaped granules ((major axis + minor axis) / 2), and the particle size is preferably the arithmetic mean value of the average values ​​of the major axis and minor axis of 10 or more pellet-shaped granules.In one embodiment of the present invention, the particle size can be adjusted by the stirring conditions of the sol mixture (selection of a stirring means, stirring speed, and / or stirring time, etc.), the discharge conditions or extrusion conditions of the sol mixture from a container (diameter of the discharge port, die, or nozzle, length in the discharge or extrusion direction of the discharged or extruded sol mixture during cutting), etc.

[0090] In the present invention, when the ionomer resin granules have an irregular shape, the particle size can be measured using a laser diffraction / scattering type particle size distribution measuring device, a micrometer, or a measuring microscope, and is determined, for example, by the method described in the Examples. When two or more particle size peaks appear in a graph obtained by plotting particle size (μm) on the horizontal axis and frequency (%) on the vertical axis in particle size measurement using a laser diffraction / scattering type particle size distribution measuring device, the particle size of the most frequent peak is regarded as the particle size of the irregularly shaped granules.

[0091] The branching degree per 1000 carbon atoms of the ionomer resin granules is not particularly limited, and is preferably 5 to 30, more preferably 6 to 20. The branching degree can be adjusted by the polymerization temperature during synthesis of the ethylene-(meth)acrylic acid ester copolymer (X), which is the raw material of the ionomer resin. The branching degree per 1000 carbon atoms can be measured by the DDMAS method using solid-state NMR.

[0092] The melting point of the ionomer resin granules is preferably 50° C. or higher, more preferably 60° C. or higher, and even more preferably 80° C. or higher from the viewpoint of heat resistance, and is preferably 200° C. or lower, more preferably 180° C. or lower, and even more preferably 150° C. or lower from the viewpoint of exhibiting suitable adhesive strength to a substrate when preparing a laminated glass. The melting point can be measured based on JIS K7121:2012. Specifically, it can be measured using a differential scanning calorimeter (DSC) under conditions of a cooling rate of −10° C. / min and a heating rate of 10° C. / min, and can be determined from the peak top temperature of the melting peak in the second heating.

[0093] The heat of fusion of the ionomer resin granules is preferably 0 J / g or more and 25 J / g or less. The heat of fusion can be measured based on JIS K7122:2012. Specifically, it can be measured using a differential scanning calorimeter (DSC) under conditions of a cooling rate of -10°C / min and a heating rate of 10°C / min, and calculated from the area of ​​the melting peak during the second heating.

[0094] The melt flow rate (MFR) of the ionomer resin granules measured in accordance with JIS K7210-1:2014 under conditions of 190°C and 2.16 kg is preferably 0.1 g / 10 min or more, more preferably 0.3 g / 10 min or more, even more preferably 0.7 g / 10 min or more, even more preferably 1.0 g / 10 min or more, particularly preferably 1.5 g / 10 min or more, and preferably 50 g / 10 min or less, more preferably 30 g / 10 min or less, particularly preferably 10 g / 10 min or less. When the MFR is equal to or greater than the lower limit and equal to or less than the upper limit, molding processing can be performed with reduced deterioration due to heat, and a resin sheet with excellent penetration resistance can be obtained.

[0095] The melting point, heat of fusion and MFR of the ionomer resin granules can be adjusted by the molecular weight of the ionomer resin, as well as the content of (meth)acrylic acid units (A), (meth)acrylic acid neutralized units (B), and ethylene units (C), and optionally the (meth)acrylic acid ester units (D).

[0096] The storage modulus (E') at 50°C measured by dynamic viscoelasticity measurement of the ionomer resin granules is preferably 20 MPa or more, more preferably 30 MPa or more, even more preferably 40 MPa or more, and particularly preferably 50 MPa or more, from the viewpoint of good self-supporting property (i.e., high elastic modulus), particularly in a high-temperature environment (high elastic modulus in a high-temperature environment). The upper limit of the storage modulus (E') is not particularly limited and may be 1000 MPa. The storage modulus can be adjusted by the molecular weight of the ionomer resin, and the contents of the (meth)acrylic acid unit (A), the (meth)acrylic acid neutralized product unit (B), and the ethylene unit (C) of the ionomer resin, and the (meth)acrylic acid ester unit (D) optionally contained therein.

[0097] The ionomer resin granules obtained by the method of the present invention have high transparency because the salt content in the ionomer resin granules is reduced. The haze of the ionomer resin granules is preferably 2.0% or less, more preferably 1.5% or less, and even more preferably 1.0% or less. Since the smaller the haze, the higher the transparency of the ionomer resin granules, the lower limit is not particularly limited and may be, for example, 0.01% or more. The haze of the ionomer resin granules is measured using a haze meter in accordance with JIS K7136:2000.

[0098] The ionomer resin granules obtained by the method of the present invention have high transparency even when the ionomer resin granules absorb water (when absorbing water) because the salt in the ionomer resin granules is sufficiently removed and the salt content is low. The haze of the ionomer resin granules when they absorb water (water absorption haze) is preferably 9.0% or less, more preferably 5.0% or less, even more preferably 4.0% or less, even more preferably 3.0% or less, and particularly preferably 2.5% or less. The smaller the water absorption haze, the higher the transparency of the ionomer resin granules when absorbing water, so the lower limit is not particularly limited and may be, for example, 0.01% or more. The water absorption haze can be measured in accordance with JIS K7136:2000. Specifically, a resin sheet formed from ionomer resin granules is immersed in ion-exchanged water at 23°C for 300 hours, then taken out, and the moisture adhering to the surface of the resin sheet is wiped off to use the resin sheet as a test piece, which can be measured with a haze meter, for example, by the method described in the Examples.

[0099] According to the study by the present inventors, if the crystallinity of the ionomer resin is too high, the ionomer resin tends to whiten, and therefore the transparency (transparency during slow cooling) tends to decrease when the ionomer resin is slowly cooled to promote the crystallization of the resin. The ionomer resin granules obtained by the present invention have a total content of (meth)acrylic acid units (A) and (meth)acrylic acid neutralized units (B) in the resin of 6 mol % or more, so that the crystallinity is not too high and the resin has high transparency even during slow cooling. The haze (slow-cooling haze) in the state where the crystallization of the resin is promoted by slow cooling of the ionomer resin granules obtained by the method of the present invention is preferably 5.0% or less, more preferably 4.0% or less, even more preferably 3.0% or less, even more preferably 2.5% or less, and particularly preferably 2.0% or less. The smaller the haze, the higher the transparency of the ionomer resin, so the lower limit is not particularly limited, and may be, for example, 0.01% or more. The slow-cooling haze can be measured in accordance with JIS K7136:2000. Specifically, a resin sheet formed from the ionomer resin granules is placed between two glass plates as an interlayer to prepare a laminated glass, and the laminated glass is heated to 140°C, and then slowly cooled from 140°C to 23°C at a rate of 0.1°C / min, and the haze is measured with a haze meter.

[0100] In one embodiment of the present invention, the ionomer resin granules of the present invention have a low coloration degree, and are preferably colorless. From the viewpoint of low coloration, the yellowness index (YI) of the ionomer resin granules of the present invention is preferably 2.0 or less, more preferably 1.8 or less, even more preferably 1.5 or less, and particularly preferably 1.0 or less. The smaller the yellowness index (YI), the less the coloration of the ionomer resin granules, so the lower limit is not particularly limited and may be, for example, 0 or more. The yellowness index (YI) can be measured using a colorimeter in accordance with JIS Z8722:2009.

[0101] [Porous ionomer resin granules] The present invention also includes porous ionomer resin granules having a pore median diameter of more than 1.2 μm and not more than 50 μm. The porous ionomer resin granules of the present invention are granular porous ionomer resins having a pore median diameter of more than 1.2 μm and not more than 50 μm, and therefore have excellent ease of drying of the solvent in the ionomer resin granules and excellent salt removal properties. The same description regarding the median diameter of the ionomer resin granules obtained by the method of the present invention applies to the median diameter of the porous ionomer resin granules of the present invention.

[0102] In one embodiment of the present invention, the porous ionomer resin granules of the present invention preferably have a porosity of 60% or more from the viewpoint of ease of drying the solvent in the ionomer resin granules and removal of salts. The same description regarding the porosity of the ionomer resin granules obtained by the method of the present invention applies to the porosity of the porous ionomer resin granules of the present invention. In this embodiment, from the viewpoint of the removability of salt in the ionomer resin granules, the porous ionomer resin granules of the present invention preferably have a value obtained by dividing the porosity (%) by the median pore diameter (μm) [porosity (%) / median pore diameter (μm)] of 1 to 50. With regard to the above-mentioned value of the porous ionomer resin granules of the present invention, the description regarding the above-mentioned value of the ionomer resin granules obtained by the method of the present invention similarly applies.

[0103] In one embodiment of the present invention, the porous ionomer resin granules of the present invention preferably have a particle size of 0.01 mm or more and 8 mm or less from the viewpoints of handling and removal of salt from the ionomer resin granules. Also, in one embodiment of the present invention, the porous ionomer resin granules of the present invention preferably have a pellet shape or an irregular shape from the viewpoints of productivity and removal of salt. With respect to the particle size and shape of the porous ionomer resin granules of the present invention, the description regarding the particle size and shape of the ionomer resin granules obtained by the method of the present invention applies similarly.

[0104] In one embodiment of the present invention, the content of the salt consisting of a strong acid and a strong base in the porous ionomer resin granules of the present invention is preferably 1000 mg / kg or less from the viewpoint of improving the transparency of the ionomer resin granules, particularly the transparency when absorbing water. Regarding the type and content of the salt in the porous ionomer resin granules of the present invention, the description regarding the type and content of the salt in the ionomer resin granules obtained by the method of the present invention similarly applies.

[0105] In a preferred embodiment of the present invention, the porous ionomer resin granules of the present invention are preferably the above-mentioned ionomer resin granules obtained by the method of the present invention, and the description regarding the ionomer resin granules obtained by the method of the present invention described in the section <Ionomer resin granules> similarly applies.

[0106] [Resin composition] If necessary, additives may be added to the ionomer resin granules obtained by the method of the present invention or the porous ionomer resin granules of the present invention to form a resin composition. The resin composition of the present invention contains the ionomer resin granules obtained by the method of the present invention or the porous ionomer resin granules of the present invention and additives. Examples of additives that may be optionally included include ultraviolet absorbers, antiaging agents, antioxidants, heat deterioration inhibitors, light stabilizers, anti-sticking agents, lubricants, release agents, polymer processing aids, antistatic agents, flame retardants, dyes and pigments, organic dyes, matting agents, and fluorescent materials. These additives may be used alone or in combination of two or more. Among these additives, ultraviolet absorbers, antiaging agents, antioxidants, heat deterioration inhibitors, light stabilizers, anti-sticking agents, lubricants, release agents, polymer processing aids, and organic dyes are preferred.

[0107] UV absorbers are compounds that have the ability to absorb UV rays, and are said to have the function of converting light energy into heat energy. Examples of UV absorbers include benzophenones, benzotriazoles, triazines, benzoates, salicylates, cyanoacrylates, oxalic acid anilides, malonic acid esters, and formamidines. These may be used alone or in combination of two or more.

[0108] Benzotriazoles are preferred as ultraviolet absorbents because they are highly effective in suppressing the deterioration of optical properties, such as coloration, caused by exposure to ultraviolet light. Preferred examples of benzotriazoles include 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol (manufactured by BASF; trade name: TINUVIN329), 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (manufactured by BASF; trade name: TINUVIN234), 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-t-octylphenol] (manufactured by ADEKA Corporation; trade name: Adeka STAB LA-31), and 2-(5-octylthio-2H-benzotriazol-2-yl)-6-tert-butyl-4-methylphenol. These may be used alone or in combination of two or more.

[0109] Examples of triazine ultraviolet absorbers include 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methylphenyl)-1,3,5-triazine (manufactured by ADEKA CORPORATION; product name: Adeka STAB LA-F70), its analogues, hydroxyphenyltriazine ultraviolet absorbers (manufactured by BASF; product names: TINUVIN 477, TINUVIN 460), 2,4-diphenyl-6-(2-hydroxy-4-hexyloxyphenyl)-1,3,5-triazine, etc. These may be used alone or in combination of two or more.

[0110] Examples of the antiaging agent include known materials. Specific examples of the antiaging agent include phenolic compounds such as hydroquinone, hydroquinone monomethyl ether, 2,5-di-t-butylphenol, 2,6-di(t-butyl)-4-methylphenol, and mono(or di, or tri)(α-methylbenzyl)phenol; bisphenol compounds such as 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 4,4'-butylidenebis(3-methyl-6-t-butylphenol), and 4,4'-thiobis(3-methyl-6-t-butylphenol); benzimidazole compounds such as 2-mercaptobenzimidazole and 2-mercaptomethylbenzimidazole; amine-ketone compounds such as 1,2-ethoxy-2,2,4-trimethylquinoline, reaction products of diphenylamine and acetone, and 2,2,4-trimethyl-1,2-dihydroquinoline polymers; aromatic secondary amine compounds such as N-phenyl-1-naphthylamine, alkylated diphenylamine, octylated diphenylamine, 4,4'-bis(α,α-dimethylbenzyl)diphenylamine, p-(p-toluenesulfonylamido)diphenylamine, and N,N'-diphenyl-p-phenylenediamine; and thiourea compounds such as 1,3-bis(dimethylaminopropyl)-2-thiourea and tributylthiourea. These may be used alone or in combination of two or more.

[0111] The antioxidant is effective in preventing the oxidative deterioration of the resin by itself in the presence of oxygen. Examples of the antioxidant include phosphorus-based antioxidants, hindered phenol-based antioxidants, and thioether-based antioxidants. These antioxidants may be used alone or in combination of two or more. Among them, from the viewpoint of the effect of preventing the deterioration of optical properties due to coloring, phosphorus-based antioxidants and hindered phenol-based antioxidants are preferred, and a combination of a phosphorus-based antioxidant and a hindered phenol-based antioxidant is more preferred.

[0112] When a phosphorus-based antioxidant and a hindered phenol-based antioxidant are combined, the mass ratio of the phosphorus-based antioxidant to the hindered phenol-based antioxidant is preferably 1:5 to 2:1, and more preferably 1:2 to 1:1.

[0113] Examples of preferred phosphorus-based antioxidants include 2,2-methylenebis(4,6-di-t-butylphenyl)octylphosphite (manufactured by ADEKA Corporation; trade name: Adeka STAB HP-10), tris(2,4-di-t-butylphenyl)phosphite (manufactured by BASF; trade name: IRGAFOS168), and 3,9-bis(2,6-di-t-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane (manufactured by ADEKA Corporation; trade name: Adeka STAB PEP-36). These may be used alone or in combination of two or more.

[0114] Examples of preferred hindered phenol-based antioxidants include pentaerythrityl-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] (manufactured by BASF; trade name: IRGANOX1010), octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate (manufactured by BASF; trade name: IRGANOX1076), etc. These may be used alone or in combination of two or more.

[0115] The heat deterioration inhibitor can prevent the heat deterioration of the resin by capturing polymer radicals generated when exposed to high heat in a substantially oxygen-free state. Examples of preferred heat deterioration inhibitors include 2-t-butyl-6-(3'-t-butyl-5'-methyl-hydroxybenzyl)-4-methylphenyl acrylate (manufactured by Sumitomo Chemical Co., Ltd.; product name: Sumilizer GM), 2,4-di-t-amyl-6-(3',5'-di-t-amyl-2'-hydroxy-α-methylbenzyl)phenyl acrylate (manufactured by Sumitomo Chemical Co., Ltd.; product name: Sumilizer GS), etc. These may be used alone or in combination of two or more.

[0116] A light stabilizer is a compound that is said to have the function of capturing radicals generated mainly by oxidation due to light. Examples of preferred light stabilizers include hindered amines such as compounds having a 2,2,6,6-tetraalkylpiperidine skeleton. These may be used alone or in combination of two or more.

[0117] Examples of the anti-sticking agent include salts or esters of fatty acids, esters of polyhydric alcohols, inorganic salts, inorganic oxides, and particulate resins. Examples of preferred anti-sticking agents include calcium stearate, calcium carbonate, calcium sulfate, magnesium sulfate, barium sulfate, silicon dioxide (manufactured by Evonik; trade name: Aerosil), particulate acrylic resins, and the like. These may be used alone or in combination of two or more.

[0118] Examples of lubricants include stearic acid, behenic acid, stearamide acid, methylene bisstearamide, hydroxystearic acid triglyceride, paraffin wax, ketone wax, octyl alcohol, hardened oil, etc. These may be used alone or in combination of two or more.

[0119] Examples of the release agent include higher alcohols such as cetyl alcohol and stearyl alcohol, and higher fatty acid esters of glycerin such as monoglyceride stearate and diglyceride stearate, etc. These may be used alone or in combination of two or more.

[0120] As the polymer processing aid, polymer particles having a particle size of 0.05 to 0.5 μm, which can be produced by emulsion polymerization, are usually used. The polymer particles may be single-layer particles made of a polymer with a single composition ratio and a single intrinsic viscosity, or may be multi-layer particles made of two or more polymers with different composition ratios or intrinsic viscosities. These may be used alone or in combination of two or more. Among these, a two-layer structure particle having a polymer layer with a low intrinsic viscosity in the inner layer and a polymer layer with a high intrinsic viscosity of 5 dl / g or more in the outer layer is preferred. The intrinsic viscosity of the polymer processing aid is preferably 3 to 6 dl / g. If the intrinsic viscosity is too small, the effect of improving moldability tends to be low, and if the intrinsic viscosity is too large, the moldability of the copolymer tends to decrease.

[0121] As an example of the organic dye, a compound having a function of converting ultraviolet light into visible light is preferably used. The organic dye may be used alone or in combination of two or more kinds.

[0122] Examples of fluorescent substances include fluorescent pigments, fluorescent dyes, fluorescent white dyes, fluorescent brighteners, fluorescent bleaches, etc. These may be used alone or in combination of two or more.

[0123] The content of the various additives can be appropriately selected within a range that does not impair the effects of the present invention, and the total content of the various additives is preferably 7 mass% or less, more preferably 5 mass% or less, and even more preferably 4 mass% or less, relative to the total mass of the resin composition.

[0124] In one embodiment of the present invention, the content of the ionomer resin granules obtained by the method of the present invention or the porous ionomer resin granules of the present invention is, from the viewpoint of improving transparency, preferably 90 mass% or more, more preferably 95 mass% or more, even more preferably 98 mass% or more, and even more preferably 99 mass% or more, relative to the total mass of the resin composition, and is preferably 100 mass% or less, more preferably 99.99 mass% or less.

[0125] The various additives may be added when the ionomer resin granules are produced, or after the ionomer resin granules are produced, or may be added when the resin sheet described below is produced.

[0126] The resin composition of the present invention may be in a granular form such as pellets to enhance the convenience during storage, transportation, or molding. When the resin composition is pelletized, it can be obtained, for example, by cutting a strand obtained by a melt extrusion method. When pelletizing by the melt extrusion method, the temperature of the resin or resin composition during melt extrusion is preferably 150°C or higher, more preferably 170°C or higher, from the viewpoint of stabilizing the discharge from the extruder. In addition, the temperature is preferably 250°C or lower, more preferably 230°C or lower, from the viewpoint of suppressing the deterioration of the resin due to thermal decomposition. In the ionomer resin granules of the present invention and the resin composition of the present invention, when the resin is pelletized by the melt extrusion method in this way, the amount of volatilized substances is small and odor is unlikely to be generated, so that the working environment is unlikely to deteriorate.

[0127] [Resin sheet] The present invention also includes a resin sheet comprising at least one layer containing the porous ionomer resin granules of the present invention as a resin component. The resin sheet of the present invention has excellent transparency because it comprises a layer containing the porous ionomer resin granules of the present invention as a resin component.

[0128] The resin sheet of the present invention includes at least one layer (hereinafter, also referred to as layer (x)) containing the porous ionomer resin granules of the present invention as a resin component. The layer (x) is a layer containing the porous ionomer resin granules of the present invention and optionally additives. The resin sheet of the present invention may be composed of only layer (x), or may be a laminate including at least one layer (x). The laminate is not particularly limited, but may be, for example, a laminate including two or more layers (x), or a laminate including one or more layers (x) and one or more other layers. When the layer (x) or other layer is a plurality of layers, the resin granules or resin compositions included in each layer may be the same or different.

[0129] The other layer may be a layer containing a known resin. Examples of the resin include polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyurethane, polytetrafluoroethylene, acrylic resin, polyamide, polyacetal, polycarbonate, and polyester, such as polyethylene terephthalate, polybutylene terephthalate, cyclic polyolefin, polyphenylene sulfide, polysulfone, polyethersulfone, polyarylate, liquid crystal polymer, polyimide, and thermoplastic elastomer. The other layer may also contain one or more additives such as the additives, plasticizers, pigments, dyes, heat-shielding materials (e.g., inorganic heat-shielding fine particles or organic heat-shielding materials having infrared absorbing ability), and functional inorganic compounds, as necessary.

[0130] In one embodiment of the present invention, from the viewpoint of excellent bubble releasing properties when the resin sheet and the substrate are thermocompression bonded, the resin sheet of the present invention preferably has an uneven structure on the surface by a conventionally known method such as melt fracture or embossing. The shape of the melt fracture and embossing may be appropriately selected from conventionally known shapes.

[0131] The thickness of each layer (x) in the resin sheet of the present invention is preferably 0.1 mm or more, more preferably 0.2 mm or more, even more preferably 0.3 mm or more, particularly preferably 0.4 mm or more, and is preferably 5 mm or less, more preferably 4 mm or less, even more preferably 2 mm or less, particularly preferably 1 mm or less. When the resin sheet has a plurality of layers (x), the thicknesses of each of the layers (x) in the resin sheet may be the same or different.

[0132] The thickness of the resin sheet of the present invention is preferably 0.1 mm or more, more preferably 0.2 mm or more, even more preferably 0.3 mm or more, even more preferably 0.4 mm or more, particularly preferably 0.5 mm or more, especially more preferably 0.6 mm or more, especially more preferably 0.7 mm or more, and especially preferably 0.75 mm or more, and is preferably 20 mm or less, more preferably 15 mm or less, even more preferably 10 mm or less, even more preferably 5 mm or less, especially preferably 4 mm or less, especially more preferably 2 mm or less, and especially more preferably 1 mm or less.

[0133] The thickness of the resin sheet is measured by a conventionally known method, for example, using a contact or non-contact thickness meter, etc. The resin sheet may be in a state of being wound into a roll, or in a state of individual sheets.

[0134] In a preferred embodiment of the present invention, the resin sheet of the present invention exhibits the same storage modulus, haze, water absorption haze, annealing haze and yellowness index at 50°C as those of the ionomer resin granules obtained by the method of the present invention described in the section <Ionomer resin granules>.

[0135] The resin sheet of the present invention preferably has a low water content from the viewpoint of being less likely to foam during the production of laminated glass. The water content of the resin sheet is preferably 1 mass% or less, more preferably 0.5 mass% or less, further preferably 0.02 mass% or less, and particularly preferably 0.01 mass% or less. The water content can be measured by coulometric titration.

[0136] The method for producing the resin sheet of the present invention is not particularly limited. For example, the porous ionomer resin granules of the present invention or the resin composition of the present invention are uniformly kneaded, and then the layer (x) can be produced by a known film-forming method such as an extrusion method, a calendar method, a press method, a solution casting method, a melt casting method, or an inflation method. The layer (x) may be used alone as a resin sheet. If necessary, two or more layers (x), or one or more layers (x) and one or more other layers may be laminated by press molding or the like to form a laminated resin sheet, or two or more layers (x), or one or more layers (x) and one or more other layers may be molded by a co-extrusion method to form a laminated resin sheet. When the layer (x) or other layer is a plurality of layers, the resin compositions constituting each layer may be the same or different.

[0137] Among known film-forming methods, a method of producing a resin sheet using an extruder is preferably used. The resin temperature during extrusion is preferably 150°C or higher, more preferably 170°C or higher, from the viewpoint of stabilizing the discharge of the resin from the extruder and reducing mechanical troubles. The resin temperature during extrusion is preferably 250°C or lower, more preferably 230°C or lower, from the viewpoint of reducing the decomposition of the resin and the deterioration of the resin associated with the decomposition. In addition, in order to efficiently remove volatile substances, it is preferable to remove the volatile substances from the vent of the extruder by reducing pressure.

[0138] [Laminated glass interlayer and laminated glass] The resin sheet of the present invention can be suitably used as a laminated glass interlayer (also simply referred to as an interlayer). Thus, the present invention includes a laminated glass interlayer made of the resin sheet of the present invention. The present invention also includes laminated glass having two glass plates and the laminated glass interlayer of the present invention disposed between the two glass plates. The laminated glass of the present invention has an excellent transparency because it has a laminated glass interlayer made of the resin sheet.

[0139] As the glass plate to be laminated with the interlayer film of the present invention, for example, inorganic glass such as float glass plate, polished glass plate, figured glass plate, wired glass plate, heat absorbing glass plate, etc., as well as conventionally known organic glass such as polymethyl methacrylate, polycarbonate, etc. can be used. These may be either colorless or colored. These may be used alone or in combination of two or more. In addition, the thickness of one glass plate is preferably 100 mm or less, and the thicknesses of the two glass plates may be the same or different.

[0140] The laminated glass obtained by sandwiching the resin sheet of the present invention between two pieces of glass can be produced by a conventionally known method. For example, a method using a vacuum laminator, a method using a vacuum bag, a method using a vacuum ring, a method using a nip roll, etc. In addition, a method in which the glass sheets are temporarily pressed together by the above method, and then put into an autoclave for main bonding can also be mentioned.

[0141] When using a vacuum laminator, for example, 1×10 -6 ~1×10 -1 Laminated glass can be produced by laminating a glass sheet, an interlayer film, and an optional layer (such as an adhesive resin layer) under a reduced pressure of 100 MPa at 60 to 200° C., particularly 80 to 160° C. A method using a vacuum bag or a vacuum ring is described in, for example, European Patent No. 1235683, and a ... -2 ~3×10 -2 Laminated glass can be produced by laminating glass plates, an interlayer film, and any optional layers at 100 to 160°C under a pressure of about 100 MPa.

[0142] An example of a manufacturing method using a nip roll is a method in which a glass plate, an interlayer film, and an arbitrary layer are laminated, degassed with a roll at a temperature below the flow start temperature of the interlayer film, and then pressure-bonded at a temperature close to the flow start temperature.Specifically, for example, a method in which the laminate is heated to 30 to 70°C with an infrared heater or the like, degassed with a roll, further heated to 50 to 120°C, and then pressure-bonded with a roll is exemplified.

[0143] When the laminated glass is subjected to pressure bonding using the above-mentioned method and then placed in an autoclave for further pressure bonding, the operating conditions for the autoclave step are appropriately selected depending on the thickness and / or configuration of the laminated glass. For example, it is preferable to treat the laminated glass under a pressure of 0.5 to 1.5 MPa at 100 to 160°C for 0.5 to 3 hours.

[0144] The ionomer resin granules of the present invention and the resin sheet of the present invention have high transparency and high adhesion to glass, so that the laminated glass of the present invention has excellent transparency. In one embodiment of the present invention, the haze of the laminated glass of the present invention is preferably 1.0% or less, more preferably 0.8% or less, and further preferably 0.5% or less. Since the smaller the haze, the higher the transparency of the laminated glass, the lower limit is not particularly limited and may be, for example, 0.01%. The haze of the laminated glass is measured using a haze meter in accordance with JIS K7136:2000.

[0145] The laminated glass of the present invention is also excellent in transparency during annealing. The transparency during annealing can be evaluated by the haze during annealing (annealing haze). The annealing haze of the laminated glass of the present invention is preferably 5.0% or less, more preferably 4.0% or less, even more preferably 3.0% or less, even more preferably 2.5% or less, and particularly preferably 2.0% or less. Since the smaller the haze, the higher the transparency of the laminated glass, the lower limit is not particularly limited, and may be, for example, 0.01% or more. The annealing haze of the laminated glass can be measured in accordance with JIS K7136:2000. Specifically, the haze of the laminated glass is measured using a haze meter after heating the laminated glass to 140°C and then annealing it from 140°C to 23°C at a rate of 0.1°C / min, and can be measured, for example, by the method described in the Examples.

[0146] The laminated glass of the present invention is preferably less colored and as colorless as possible. The yellowness index (YI) of the laminated glass of the present invention is preferably 3.0 or less, more preferably 2.0 or less, further preferably 1.5 or less, particularly preferably 1.0 or less, and may be preferably 0 or more. The yellowness index (YI) can be measured using a colorimeter in accordance with JIS Z8722.

[0147] The adhesive strength between the glass plates and the interlayer film in the laminated glass of the present invention is measured, for example, by the compression shear strength test described in WO1999 / 058334. From the viewpoint of improving the adhesive strength, the compressive shear strength is preferably 15 MPa or more, more preferably 20 MPa or more, and particularly preferably 25 MPa or more. From the viewpoint of improving the penetration resistance of the laminated glass, the compressive shear strength may be 50 MPa or less.

[0148] As described above, a resin sheet comprising at least one layer containing the ionomer resin granules of the present invention as a resin component is useful as an interlayer film for laminated glass. The interlayer film for laminated glass is particularly preferable as an interlayer film for laminated glass for structural materials (facades) because of its excellent adhesion to substrates such as glass, transparency, and self-supporting properties.

[0149] Furthermore, the laminated glass of the present invention can be suitably used not only as an interlayer film for laminated glass for structural materials, but also as a windshield for an automobile, a side glass for an automobile, a sunroof for an automobile, a rear glass for an automobile, glass for a head-up display, a laminate for an exterior wall and a roof, a panel, a door, a window, a wall, a roof, a sunroof, a sound insulation wall, a display window, a balcony, a handrail wall, and other building materials, a partition glass member for a conference room, a solar panel, and the like. EXAMPLES

[0150] Hereinafter, the embodiments of the present invention will be described in detail. Note that the scope of the present invention is not limited to the embodiments described here, and various modifications can be made without departing from the spirit of the present invention.

[0151] [Content of each monomer unit in ionomer resin (Y) and raw material resin] The contents of each of the monomer units, i.e., (meth)acrylic acid unit (A), (meth)acrylic acid neutralized unit (B), ethylene unit (C) and (meth)acrylic acid ester unit (D), in the ionomer resin granules obtained in the Examples and Comparative Examples were determined by analysis as follows: Each content corresponds to the content of each monomer unit of the ionomer resin (Y) contained in the sol-like mixture in the Examples and Comparative Examples.

[0152] The ionomer resin granules obtained in each of the examples and comparative examples were dissolved in a mixed solvent of dehydrated toluene / dehydrated acetic acid (75 / 25% by mass), reacted at 100°C for 2 hours, and then reprecipitated in a mixed solvent of acetone / water (80 / 20% by mass) to convert the (meth)acrylic acid neutralized unit (B) to the (meth)acrylic acid unit (A). The resulting resin was thoroughly washed with water and then dried, and the following steps (1) to (3) were carried out on the dried resin. (1) The components of the monomer units that make up the resin were analyzed by pyrolysis GC-MS. (2) The acid value of the resin was measured in accordance with JIS K0070:1992. (3) Using a mixed solvent of deuterated toluene and deuterated methanol, the resin 1 H-NMR (400 MHz, manufactured by JEOL Ltd.) measurements were carried out. (4) In addition, the ionomer resin granules obtained in the examples and comparative examples were each subjected to a microwave decomposition pretreatment using nitric acid. Then, the type and amount of metal ions in the (meth)acrylic acid neutralization unit (B) were identified by ICP emission spectrometry (Thermo Fisher Scientific iCAP6500Duo). From the above (1), the types and structures of the (meth)acrylic acid ester units (D) and the (meth)acrylic acid units (A) were identified. From this information and the above (2) and (3), the ratio of ethylene units (C) / (meth)acrylic acid ester units (D) / (total of (meth)acrylic acid units (A) and (meth)acrylic acid neutralized units (B)) was calculated. Furthermore, from the above information (4), the ratio of ethylene units (C) / (meth)acrylic acid ester units (D) / (meth)acrylic acid units (A) / (meth)acrylic acid neutralized units (B) was calculated. The content of each monomer unit of the raw material ethylene-(meth)acrylic acid ester copolymer (X) was measured by dissolving it in deuterated toluene or deuterated THF, 1 The measurements were performed using H-NMR (400 MHz, manufactured by JEOL Ltd.) and calculations were performed.

[0153] [Melt flow rate (MFR) of raw resin] The melt flow rates of the raw resins used in the examples and comparative examples were measured in accordance with JIS K7210-1: 2014. Specifically, each resin was melted in a cylinder and extruded from a die with a nominal hole diameter of 2.095 mm installed at the bottom of the cylinder under conditions of 190°C and a load of 2.16 kg, and the amount of resin extruded per 10 minutes (g / 10 minutes) was measured.

[0154] [Porosity and median pore size of ionomer resin granules] The ionomer resin granules obtained in the examples and comparative examples were freeze-dried at -80°C, and 0.5 g of the granules was placed in a standard 5 cc powder cell (stem volume 0.4 cc). The porosity and median diameter of the pores of the ionomer resin granules were measured using a Micromeritics pore distribution measuring device (Shimadzu Corporation, Autopore V9620) under the condition of an initial pressure of 2.6 kPa. The median diameter of the pores is the median diameter (d50) for all pores in the range of pore diameters of 0.005 to 100 μm in the Log differential pore volume distribution. The mercury parameters were a mercury contact angle of 130 degrees and a mercury surface tension of 485 hynes / cm.

[0155] [Particle size of ionomer resin granules] The particle size of the granules obtained in the Examples and Comparative Examples was calculated according to the following procedure. When the ionomer resin granules have a pellet shape, 10 pellet-shaped granules are randomly selected from the obtained pellet-shaped granules, and the height of the pellet-shaped granules as the X-axis length (Lx), the length of the longest part of the diameter of the bottom of the pellet-shaped granules as the Y-axis length (Ly), and the length of the shortest part of the diameter of the bottom of the pellet-shaped granules as the Z-axis length (Lz) are measured with a micrometer. The average value ((Lx+Ly+Lz) / 3) of the X-axis, Y-axis, and Z-axis lengths of each pellet-shaped granule is calculated. The arithmetic average value of the average values ​​of the X-axis, Y-axis, and Z-axis lengths of each pellet-shaped granule is taken as the particle size of the pellet-shaped granule. When the ionomer resin granules have an irregular shape, the particle size distribution of the irregular shaped granules was measured using a laser diffraction / scattering type particle size distribution measuring device (manufactured by Horiba, Ltd., product name: LA-950). The particle size of the peak top in the graph obtained by plotting particle size (μm) on the horizontal axis and frequency (%) on the vertical axis was adopted as the particle size of the irregular shaped granules. When two or more peaks were obtained, the particle size of the most frequent peak was taken as the particle size of the irregular shaped granules.

[0156] [Content of salts of strong acids and strong bases (amount of remaining inorganic salts)] 0.1 g of the ionomer resin granules obtained in each of the examples and comparative examples was weighed out, 10 mL of ultrapure water was added, and the mixture was heated at 90°C for 1 hour. The mixture was then allowed to cool and filtered through a filter with a mesh size of 0.45 μm. The filtrate obtained by filtration was used as a sample liquid, and measurements were carried out under the following conditions using an ion chromatograph (manufactured by Shimadzu Corporation). The amount of chloride ions or nitrate ions was determined based on the peak area obtained by the measurement, and the amount of the chloride ions or nitrate ions was converted into the amount of sodium salt to determine the amount of remaining inorganic salt. (Measurement conditions) Eluent: a mixture of aqueous sodium carbonate (0.6 mmol / L) and aqueous sodium bicarbonate (12 mmol / L); Flow rate: 1.0mL / min; Column temperature: 40°C; Column: IC-SA2 (250L x 4.0) The amount of residual inorganic salt contained in the ionomer resin (Y) contained in the sol-like mixture obtained in the Examples and Comparative Examples was calculated from the amount of the raw material resin, the amount of the strong base used in the saponification reaction, and the amount of the strong acid used in the demetallation reaction, the amount of (meth)acrylic acid ester modification in the raw material resin, the degree of neutralization, and the molecular weights of the strong base and strong acid.

[0157] [Transparency when absorbing water (water absorption haze)] The ionomer resin granules obtained in the examples and comparative examples were melt-kneaded at 210°C, and the melt-kneaded mixture was heated at 210°C and subjected to a pressure of 4.9 MPa (50 kgf / cm 2 ) for 5 minutes to obtain a resin sheet having a thickness of 0.8 mm. The obtained resin sheet was cut into a 50 mm square, and the cut sample was immersed in ion-exchanged water at 23°C and held for 300 hours to obtain a water-absorbed sample. After removing the water from the ion-exchanged water, the water adhering to the surface of the water-absorbed sample was wiped off, and the haze of the water-absorbed sample was measured in accordance with JIS K7136:2000 using a haze meter HZ-1 (manufactured by Suga Test Instruments Co., Ltd.).

[0158] [Transparency during annealing (annealing haze)] The resin sheet obtained in the same manner as above was sandwiched between two pieces of float glass with a thickness of 2.7 mm, and a vacuum laminator (1522N manufactured by Nisshinbo Mechatronics Inc.) was used to reduce the pressure inside the vacuum laminator at 100°C for 1 minute, and pressed at 30 kPa for 5 minutes while maintaining the reduced pressure and temperature to obtain a temporary bonded body. The temporary bonded body obtained was placed in an autoclave and treated at 140°C and 1.2 MPa for 30 minutes to obtain a laminated glass. The obtained laminated glass was heated to 140° C. and then slowly cooled at a rate of 0.1° C. / min to 23° C. The haze of the laminated glass after the slow cooling operation was measured using a haze meter HZ-1 (manufactured by Suga Test Instruments Co., Ltd.) in accordance with JIS K7136:2000.

[0159] [Raw material resin] In the examples and comparative examples, Table 1 shows the amount of methyl methacrylate (MMA) modification or the amount of ethyl acrylate (EA) modification and the MFR of each ethylene-(meth)acrylic acid ester copolymer (X) used as a raw material. As EMMA1, "Acryft" (registered trademark) WK307 manufactured by Sumitomo Chemical Co., Ltd. was used, and as EEA1, NUC-6070 manufactured by NUC Corporation was used.

[0160] [Table 1]

[0161] [Example 1] 100 parts by mass of EMMA1 shown in Table 1 was introduced into a SUS pressure vessel, 233 parts by mass of toluene was added thereto, and the mixture was stirred at 60°C under a pressure of 0.02 MPa to dissolve EMMA1. 96 parts by mass of a methanol solution of sodium hydroxide (20% by mass) was added to the obtained solution, and the mixture was stirred at 100°C for 4 hours to saponify EMMA1, converting a portion of the methyl methacrylate units to sodium methacrylate units. Next, after cooling this solution to 50°C, 92 parts by mass of nitric acid (30% by mass) was added, and the mixture was stirred at 50°C for 1 hour to convert a portion of the sodium methacrylate units to methacrylic acid, thereby obtaining a sol-like mixture (1) containing an ionomer resin (Y). The saponification degree of the ionomer resin (Y) contained in the sol-like mixture (1) was 96%, and the neutralization degree was 24%. The obtained sol-like mixture (1) was heated to 60°C, and 97 parts by mass of toluene and 32 parts by mass of methanol were added thereto to dilute the ionomer resin (Y) in the sol-like mixture (1) to a concentration of 15% by mass. The sol-like mixture (1) at 60°C obtained above was discharged into a container from a die having a diameter of 1 mm attached to the bottom of a pressure-resistant container, and was gradually cooled by being left to cool at room temperature (about 25°C) on a belt conveyor, whereby the mixture gelled at a temperature of 38°C. The gelling was judged by tilting the container containing the gel by 90° and determining whether 90% or more by volume of the gel did not flow for 1 minute or more (gelling was judged in the same manner in the following examples). The porous strand-like ionomer resin gel obtained was gradually cooled to 23°C, and pulverized with a cutting mill (Retsch, SM100) to obtain a porous irregular-shaped ionomer resin gel 1-1 having a particle size of 0.4 mm. Next, 100 parts by mass of the obtained irregular shaped ionomer resin gel 1-1 was mixed with 400 parts by mass of a mixed solvent of water / methanol (50 / 50% by mass). The slurry obtained by the above mixing was stirred at 40°C for 1 hour, and then the ionomer resin gel was filtered at room temperature. The ionomer resin gel was washed twice more with a mixed solvent of water / methanol (50 / 50% by mass) to obtain washed irregular shaped ionomer resin granules 1-2. In the above washing process, the solvent (the solvent contained in the sol-like mixture (1), here toluene and methanol) was removed from the ionomer resin gel 1-1. The obtained ionomer resin granules 1-2 had the same porosity, median pore diameter and particle size as the ionomer resin gel 1-1.

[0162] [Example 2] The sol mixture (1) obtained in Example 1 was adjusted to 50°C, and 342 parts by mass of toluene and 114 parts by mass of methanol were added thereto to dilute the ionomer resin concentration in the sol mixture (1) to 10% by mass. The sol mixture (1) at 50°C obtained above was discharged from a die having a diameter of 1 mm attached to the bottom of a pressure-resistant container, and was gradually cooled by being left to cool at room temperature on a belt conveyer, and the mixture gelled at a temperature of 32°C. The porous strand-like ionomer resin gel obtained by gradually cooling to 23°C was pulverized with a cutting mill (Retsch, SM100) to obtain a porous irregular-shaped ionomer resin gel 2-1 having a particle size of 1 mm. The resulting irregular shaped ionomer resin gel 2-1 was then washed in the same manner as in Example 1 to obtain washed irregular shaped ionomer resin granules 2-2. The resulting ionomer resin granules 2-2 had the same porosity, median pore diameter and particle size as the ionomer resin gel 2-1.

[0163] [Example 3] 100 parts by mass of EMMA1 shown in Table 1 was introduced into a SUS pressure vessel, 233 parts by mass of toluene was added thereto, and the mixture was stirred at 60°C under a pressure of 0.02 MPa to dissolve EMMA1. 96 parts by mass of a methanol solution of sodium hydroxide (20% by mass) was added to the obtained solution, and the mixture was stirred at 100°C for 4 hours to saponify EMMA1, converting a portion of the methyl methacrylate units to sodium methacrylate units. Next, after cooling this solution to 50°C, 81 parts by mass of hydrochloric acid (20% by mass) was added, and the mixture was stirred at 50°C for 1 hour to convert a portion of the sodium methacrylate units to methacrylic acid, thereby obtaining a sol-like mixture (2) containing an ionomer resin (Y). The saponification degree of the ionomer resin (Y) contained in the sol-like mixture (2) was 96%, and the neutralization degree was 22%. To the obtained sol-like mixture (2) at 50°C, 351 parts by mass of toluene and 117 parts by mass of methanol were added to dilute the ionomer resin (Y) in the sol-like mixture (2) to a concentration of 10% by mass. The sol-like mixture (2) at 50°C obtained above was discharged from a die having a diameter of 1 mm attached to the bottom of a pressure-resistant container, and was gradually cooled by being left to cool at room temperature (about 25°C) on a belt conveyor, whereupon the mixture gelled at a temperature of 32°C. The porous strand-like ionomer resin gel obtained by gradually cooling to 23°C was pulverized with a cutting mill (Retsch, SM100) to obtain a porous irregular-shaped ionomer resin gel 3-1 having a particle size of 0.8 mm. The resulting irregular shaped ionomer resin gel 3-1 was then washed in the same manner as in Example 1 to obtain washed irregular shaped ionomer resin granules 3-2. The resulting ionomer resin granules 3-2 had the same porosity, median pore diameter and particle size as the ionomer resin gel 3-1.

[0164] [Example 4] The sol mixture (2) obtained in Example 3 was adjusted to 60°C, and 106 parts by mass of toluene and 35 parts by mass of methanol were added thereto to dilute the ionomer resin (Y) concentration in the sol mixture (2) to 15% by mass. The sol mixture (2) at 60°C obtained above was discharged from a die having a diameter of 1 mm attached to the bottom of a pressure-resistant container, and was gradually cooled by being left to cool at room temperature on a belt conveyer, and the mixture gelled at a temperature of 37°C. The porous strand-shaped ionomer resin gel obtained by gradually cooling to 23°C was cut with a fan cutter (manufactured by Hoshi Plastics Co., Ltd.) to obtain a porous pellet-shaped ionomer resin gel 4-1 having a particle size of 1 mm. The pellet-shaped ionomer resin gel 4-1 thus obtained was washed in the same manner as in Example 1 to obtain washed pellet-shaped ionomer resin granules 4-2. The resulting ionomer resin granules 4-2 had the same porosity, median pore diameter, and particle size as the ionomer resin gel 4-1.

[0165] [Example 5] The sol mixture (1) obtained in Example 1 was adjusted to 55°C, and 97 parts by mass of toluene and 32 parts by mass of methanol were added thereto to dilute the ionomer resin (Y) concentration in the sol mixture (1) to 15% by mass. The sol mixture (1) at 55°C obtained above was discharged from a die having a diameter of 1 mm attached to the bottom of a pressure-resistant container, and was gradually cooled by being left to cool at room temperature on a belt conveyer, and the mixture gelled at a temperature of 37°C. The porous strand-shaped ionomer resin gel obtained by gradually cooling to 23°C was cut with a fan cutter (manufactured by Hoshi Plastics Co., Ltd.) to obtain a porous pellet-shaped ionomer resin gel 5-1 having a particle size of 1.4 mm. The resulting pellet-shaped ionomer resin gel 5-1 was then washed in the same manner as in Example 1 to obtain washed pellet-shaped ionomer resin granules 5-2. The resulting ionomer resin granules 5-2 had the same porosity, median pore diameter, and particle size as the ionomer resin gel 5-1.

[0166] [Example 6] The sol mixture (2) obtained in Example 3 was adjusted to 55°C, and 106 parts by mass of toluene and 35 parts by mass of methanol were added thereto to dilute the ionomer resin (Y) concentration in the sol mixture (2) to 15% by mass. The sol mixture (2) at 55°C obtained above was discharged from a die having a diameter of 1 mm attached to the bottom of a pressure-resistant container, and was gradually cooled by being left to cool at room temperature on a belt conveyer, and the mixture gelled at a temperature of 38°C. The porous strand-shaped ionomer resin gel obtained by gradually cooling to 23°C was cut with a fan cutter (manufactured by Hoshi Plastics Co., Ltd.) to obtain a porous pellet-shaped ionomer resin gel 6-1 having a particle size of 1.2 mm. The pellet-shaped ionomer resin gel 6-1 thus obtained was washed in the same manner as in Example 1 to obtain washed pellet-shaped ionomer resin granules 6-2. The resulting ionomer resin granules 6-2 had the same porosity, median pore diameter and particle size as the ionomer resin gel 6-1.

[0167] [Example 7] 100 parts by mass of EEA1 shown in Table 1 was introduced into a SUS pressure vessel, 233 parts by mass of toluene was added thereto, and the mixture was stirred at 60°C under a pressure of 0.02 MPa to dissolve EEA1. 96 parts by mass of a methanol solution of sodium hydroxide (20% by mass) was added to the obtained solution, and the mixture was stirred at 100°C for 4 hours to saponify EEA1, and a portion of the ethyl acrylate units was converted to sodium acrylate units. Next, after cooling this solution to 50°C, 93 parts by mass of nitric acid (30% by mass) was added, and the mixture was stirred at 50°C for 1 hour to convert a portion of the sodium acrylate units to acrylic acid, thereby obtaining a sol-like mixture (3) containing an ionomer resin (Y). The saponification degree of the ionomer resin (Y) contained in the sol-like mixture (3) was 96%, and the neutralization degree was 23%. The obtained sol-like mixture (3) at 50°C was diluted with 1020 parts by mass of toluene and 340 parts by mass of methanol so that the concentration of the ionomer resin (Y) in the sol-like mixture (3) was 5% by mass. The sol-like mixture (3) at 50°C obtained above was discharged from a die having a diameter of 1 mm attached to the bottom of a pressure-resistant container, and was gradually cooled by being left to cool at room temperature on a belt conveyer, and the mixture gelled at a temperature of 25°C. The porous strand-like ionomer resin gel obtained by gradually cooling to 23°C was pulverized with a cutting mill (Retsch, SM100) to obtain a porous irregular-shaped ionomer resin gel 7-1 having a particle size of 0.1 mm. The resulting irregular shaped ionomer resin gel 7-1 was then washed in the same manner as in Example 1 to obtain washed irregular shaped ionomer resin granules 7-2. The resulting ionomer resin granules 7-2 had the same porosity, median pore diameter and particle size as the ionomer resin gel 7-1.

[0168] [Example 8] The sol-like mixture (3) obtained in Example 7 was heated to 60°C, and 80 parts by mass of toluene and 27 parts by mass of methanol were added thereto to dilute the ionomer resin (Y) concentration in the sol-like mixture (3) to 15% by mass. The sol-like mixture (3) at 60°C obtained above was discharged from a die having a diameter of 1 mm attached to the bottom of a pressure-resistant container, and was gradually cooled by being left to cool at room temperature on a belt conveyer, and the mixture gelled at a temperature of 38°C. The porous strand-like ionomer resin gel obtained by gradually cooling to 23°C was cut with a fan cutter (manufactured by Hoshi Plastics Co., Ltd.) to obtain a porous pellet-shaped ionomer resin gel 8-1 having a particle size of 2 mm. The pellet-shaped ionomer resin gel 8-1 thus obtained was washed in the same manner as in Example 1 to obtain washed pellet-shaped ionomer resin granules 8-2. The resulting ionomer resin granules 8-2 had the same porosity, median pore diameter and particle size as the ionomer resin gel 8-1.

[0169] [Example 9] 100 parts by mass of EMMA1 shown in Table 1 was introduced into a SUS pressure vessel, 233 parts by mass of toluene was added thereto, and the mixture was stirred at 60°C under a pressure of 0.02 MPa to dissolve EMMA1. 96 parts by mass of a methanol solution of sodium hydroxide (20% by mass) was added to the obtained solution, and the mixture was stirred at 100°C for 4 hours to saponify EMMA1, converting a portion of the methyl methacrylate units to sodium methacrylate units. Next, after cooling this solution to 50°C, 95 parts by mass of nitric acid (30% by mass) was added, and the mixture was stirred at 50°C for 1 hour to convert a portion of the sodium methacrylate units to methacrylic acid, thereby obtaining a sol-like mixture (4) containing an ionomer resin (Y). The saponification degree of the ionomer resin (Y) contained in the sol-like mixture (4) was 96%, and the neutralization degree was 20%. The obtained sol-like mixture (4) was heated to 60°C, and 96 parts by mass of toluene and 32 parts by mass of methanol were added thereto to dilute the ionomer resin (Y) in the sol-like mixture (4) to a concentration of 15% by mass. The sol-like mixture (4) at 60°C obtained above was discharged from a die having a diameter of 1 mm attached to the bottom of a pressure-resistant container, and was gradually cooled by being left to cool at room temperature on a belt conveyer, whereupon the mixture gelled at a temperature of 38°C. The porous strand-like ionomer resin gel obtained by gradually cooling to 23°C was cut with a fan cutter (manufactured by Hoshi Plastics Co., Ltd.) to obtain a porous pellet-shaped ionomer resin gel 9-1 having a particle size of 3 mm. The pellet-shaped ionomer resin gel 9-1 thus obtained was washed in the same manner as in Example 1 to obtain washed pellet-shaped ionomer resin granules 9-2. The resulting ionomer resin granules 9-2 had the same porosity, median pore diameter and particle size as the ionomer resin gel 9-1.

[0170] [Comparative Example 1] The sol mixture (1) obtained in Example 1 was adjusted to 50°C. While the ionomer resin concentration in the sol mixture (1) was kept at 18.9% by mass, the sol mixture (1) was extruded into water at 20°C through a die having a diameter of 1 mm attached to the bottom of a pressure-resistant container, and cooled (quenched) to solidify, thereby obtaining a porous strand-shaped ionomer resin. The obtained strand-shaped ionomer resin was cut to obtain a porous pellet-shaped ionomer resin 1'-1 having a particle size of 3 mm. The resulting pellet-shaped ionomer resin 1'-1 was then washed in the same manner as in Example 1 to obtain washed pellet-shaped ionomer resin granules 1'-2. The resulting ionomer resin granules 1'-2 had the same porosity, median pore diameter, and particle size as the ionomer resin 1'-1.

[0171] [Comparative Example 2] The sol mixture (2) obtained in Example 3 was adjusted to 43°C, and 109 parts by mass of toluene and 36 parts by mass of methanol were added thereto to dilute the mixture so that the ionomer resin concentration in the mixture was 15% by mass. The mixture obtained above at 43°C was stirred as it was for 1 hour, but the sol mixture (2) before dilution and the dilution solvent (toluene) remained separated.

[0172] The washed ionomer resin granules obtained in the examples and comparative examples were vacuum dried for 8 hours or more, and then analyzed and evaluated. The analysis and evaluation results are shown in Table 2. In Table 2, "Tol" stands for toluene, and "MeOH" stands for methanol. In Table 2, the amount (parts by mass) of ionomer resin in the sol-like mixture represents the amount of ionomer resin obtained from 100 parts by mass of raw material resin.

[0173] [Table 2]

[0174] As shown in Table 2, the ionomer resin granules obtained in Examples 1 to 9 had a low salt content and excellent transparency even with few washings, whereas the ionomer resin granules obtained in Comparative Example 1 had low transparency.

Claims

1. A step of slowly cooling a sol mixture containing an ionomer resin and a solvent to gel the ionomer resin in the sol mixture, and optionally pulverizing the gel to obtain a porous granular ionomer resin gel; and removing the solvent from the porous granular ionomer resin gel to obtain ionomer resin granules; Including, the ionomer resin contains (meth)acrylic acid units (A), (meth)acrylic acid neutralized units (B), and ethylene units (C), and the total content of the units (A) and the units (B) is 6 mol % or more and 10 mol % or less based on all monomer units constituting the ionomer resin; A method for producing ionomer resin granules.

2. The method according to claim 1, wherein a poor solvent is not used as a refrigerant for the slow cooling.

3. The method of claim 1 , wherein the temperature of the sol-like mixture is 50° C. or higher.

4. The method of claim 1, wherein the sol mixture is slowly cooled to a temperature of 40°C or less.

5. The method according to claim 1, wherein the median diameter of the pores of the ionomer resin granules is greater than 1.2 μm and less than or equal to 50 μm.

6. The method of claim 1 , wherein the ionomer resin granules have a void content of 60% or more.

7. The method according to claim 1, wherein the ionomer resin granules have a pellet shape or an irregular shape with a particle size of 0.01 to 8 mm.

8. The method according to claim 1, wherein the ionomer resin further contains 0.01 mol % or more and 1.0 mol % or less of (meth)acrylic acid ester units (D) based on all monomer units constituting the ionomer resin.

9. The method according to claim 1 , wherein the concentration of the ionomer resin in the sol-like mixture is 18.5% by weight or less, based on the weight of the sol-like mixture.

10. 10. The method of claim 1, comprising washing the porous particulate ionomer resin gel or ionomer resin particulates with a washing liquid.

11. The method of claim 10, wherein the cleaning liquid is water, alcohol, or a mixture thereof.

12. 2. The method according to claim 1, wherein the content of the salt of a strong acid and a strong base in the ionomer resin contained in the sol-like mixture is 100,000 mg / kg or more.

13. 2. The method according to claim 1, wherein the content of the salt of a strong acid and a strong base in the ionomer resin granules is 1000 mg / kg or less.

14. The method according to claim 1, wherein the raw material is an ethylene-(meth)acrylic acid ester copolymer (X).

15. Porous ionomer resin granules having pores with a median diameter of more than 1.2 μm and not more than 50 μm.

16. 16. The porous ionomer resin granules according to claim 15, having a porosity of 60% or more.

17. The porous ionomer resin granules according to claim 16, wherein the value obtained by dividing the porosity (%) by the median diameter (μm) of the pores is 1 to 50.

18. The porous ionomer resin granules according to claim 15, which have a pellet shape or an irregular shape with a particle size of 0.01 to 8 mm.

19. 16. The porous ionomer resin granules according to claim 15, wherein the content of the salts of strong acids and strong bases is 1000 mg / kg or less.

20. A resin sheet comprising at least one layer containing the porous ionomer resin granules according to claim 15 as a resin component.

21. A laminated glass interlayer film comprising the resin sheet according to claim 20.

22. 22. A laminated glass comprising two glass sheets and the laminated glass interlayer of claim 21 disposed between the two glass sheets.