Resin composition formed by containing ionomer resin, resin sheet, and laminated glass

Abstract

The present invention relates to a resin composition that is formed by containing: an organic compound; and an ionomer resin that contains a (meth)acrylic acid unit (A), a neutralized (meth)acrylic acid unit (B) and an ethylene unit (C). The total content of the unit (A) and the unit (B) is 6-10 mol% relative to the total amount of monomer units that constitute the ionomer resin. The organic compound is a liquid at 23ºC and is at least one organic compound selected from the group consisting of aromatic compounds, alcohols, organic carboxylic acids and organic carboxylic acid esters. The content of the organic compound is 1-300 ppm by mass.

Description

Resin composition containing ionomer resin, resin sheet and laminated glass

[0001] This patent application claims priority under the Paris Convention to Japanese Patent Application No. 2021-104272 (filing date: June 23, 2021), the entire contents of which are incorporated herein by reference. The present invention relates to a resin composition comprising a specific ionomer resin and a specific organic compound, a resin sheet having one or more layers containing the resin composition, a laminated glass interlayer film comprising the resin sheet, and laminated glass having the laminated glass interlayer film.

[0002] Ionomer resins, which are neutralized ethylene-unsaturated carboxylic acid copolymers, are used in interlayer films for laminated glass because of their excellent transparency and adhesion to glass (see, for example, Patent Document 1). In recent years, there has been an increase in demand for laminated glass, and laminated glass having a laminated glass interlayer film using an ionomer resin is now required to have better properties (for example, optical properties and appearance), regardless of the manufacturing conditions of the laminated glass.

[0003] For example, Patent Document 2 describes an ionomer, which is a neutralization product of an ethylene acid copolymer containing copolymerized units of ethylene, copolymerized units of a first α,β-unsaturated carboxylic acid having 3 to 10 carbon atoms, and copolymerized units of a derivative of a second α,β-unsaturated carboxylic acid having 3 to 10 carbon atoms in specific ratios, and describes that this ionomer exhibits improved optical properties compared to conventional ionomers.

[0004] Attempts have also been made to improve other properties in addition to optical properties. For example, Patent Document 3 describes a resin composition for molded articles in which 1 to 50 parts by mass of dimer acid is added to 100 parts by mass of ionomer, and states that the addition of dimer acid achieves both improved flowability and suppressed bleed-out without substantially impairing transparency. Furthermore, for example, Patent Document 4 describes a method for producing a laminated glass interlayer using an ionomer in which the water content in the laminated glass interlayer is kept to 0.066 wt % or less, and states that improved adhesion to glass is also achieved in addition to transparency.

[0005] U.S. Patent No. 6,432,522 Patent Publication No. 2017-519083 International Publication No. 2011 / 043271 U.S. Patent No. 7,951,865

[0006] However, according to studies by the present inventors, it has been found that the resin composition described in Patent Document 3 does not have sufficient adhesion to glass (hereinafter also referred to as "glass adhesion") and transparency, is prone to discoloration during molding and processing, and is prone to loss of strength over long-term use, making it difficult to obtain a molded article with an excellent appearance free of bubbles, streaks, etc. Furthermore, it has been found that the laminated glass interlayer film using the ionomer described in Patent Document 4 does not have sufficient glass adhesion, particularly glass adhesion under high humidity conditions, is prone to discoloration during molding and is prone to loss of strength over long-term use. Therefore, the problem to be solved by the present invention is to provide a resin composition containing an ionomer resin that has excellent transparency, discoloration resistance, and adhesion to glass.

[0007] The present inventors conducted extensive research to solve the above-mentioned problems, and as a result, have completed the present invention. That is, the present invention includes the following: [1] A resin composition comprising an ionomer resin containing (meth)acrylic acid units (A), (meth)acrylic acid neutralized units (B), and ethylene units (C), and an organic compound, wherein the total content of the units (A) and the units (B) is 6 to 10 mol % based on all monomer units constituting the ionomer resin, the organic compound is liquid at 23°C, and is at least one organic compound selected from the group consisting of aromatic compounds, alcohols, organic carboxylic acids, and organic carboxylic acid esters, and the content of the organic compound is 1 ppm by mass or more and 300 ppm by mass or less. [2] The resin composition according to [1], wherein the ionomer resin further contains (meth)acrylic acid ester units (D), and the total content of the units (A), (B), and (D) is 6 to 10 mol% based on all monomer units constituting the ionomer resin. [3] The resin composition according to [1] or [2], wherein the organic compound is at least one organic compound selected from the group consisting of toluene, xylene, ethanol, 1-butanol, methacrylic acid, acrylic acid, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, methyl acrylate, ethyl acrylate, and n-butyl acrylate. [4] A resin sheet having one or more layers containing the resin composition according to any one of [1] to [3]. [5] A laminated glass interlayer film comprising the resin sheet according to [4]. [6] A laminated glass having two glass plates and the laminated glass interlayer film according to claim 5 disposed between the two glass plates.

[0008] According to the present invention, it is possible to provide a resin composition containing an ionomer resin, which has excellent transparency, coloration resistance, and adhesion to glass.

[0009] Hereinafter, 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.

[0010] [Resin Composition Comprising Ionomer Resin] The resin composition comprising the ionomer resin of the present invention (hereinafter also referred to as "ionomer resin composition") comprises an ionomer resin containing (meth)acrylic acid units (A), (meth)acrylic acid neutralization product units (B), and ethylene units (C), and a specific organic compound (hereinafter also referred to as "specific organic compound").

[0011] [Specific Organic Compound] First, the specific organic compound, which is an essential component of the ionomer resin composition of the present invention, will be described. This organic compound is liquid at 23°C under atmospheric pressure, and is one organic compound or a combination of two or more organic compounds selected from the group consisting of aromatic compounds, alcohols, organic carboxylic acids, and organic carboxylic acid esters. The content of the specific organic compound in the ionomer resin composition is 1 ppm by mass or more and 300 ppm by mass or less.

[0012] Ionomer resins may be prone to thermal degradation depending on their composition, processing temperature, processing time, etc. When resin sheets or laminated glass are produced using such ionomer resins, colored resin sheets or laminated glass are obtained. Furthermore, such laminated glass also exhibits poor adhesion between the resin sheet and glass. The present inventors therefore investigated the coloration resistance and glass adhesion of resin sheets containing ionomer resins and surprisingly found that an ionomer resin composition containing an ionomer resin and a specific proportion of a specific organic compound exhibits excellent coloration resistance and high glass adhesion. While the reason why the ionomer resin composition has excellent coloration resistance and glass adhesion due to the specific proportion of the specific organic compound is unclear, it is presumed that this is due to the ionomer resin being appropriately plasticized by the specific proportion of the specific organic compound.

[0013] Furthermore, the present inventors have unexpectedly discovered that the ionomer resin composition exhibits the following characteristics: high glass adhesion, excellent transparency, and sufficient creep resistance, particularly under high-humidity conditions, when the ionomer resin composition contains a specific organic compound in a specific proportion. Generally, ionomer resin compositions containing components other than the ionomer resin tend to exhibit inferior glass adhesion and transparency under high-humidity conditions compared to the ionomer resin itself, and also tend to exhibit insufficient creep resistance. Therefore, it was surprising that the ionomer resin composition of the present invention exhibits the above characteristics.

[0014] If the content of the specific organic compound is less than 1 ppm by mass, the discoloration resistance and glass adhesion of the ionomer resin composition are impaired. On the other hand, if the content of the specific organic compound exceeds 300 ppm by mass, the transparency (particularly the appearance) of the ionomer resin composition is likely to decrease. Therefore, for example, when a resin sheet obtained from the ionomer resin composition is used as a laminated glass interlayer, the design and appearance of the laminated glass may be impaired. Furthermore, if the content of the specific organic compound exceeds 300 ppm by mass, the creep resistance of the ionomer resin composition is likely to decrease. Therefore, for example, when a resin sheet obtained from the ionomer resin composition is used as a laminated glass interlayer, the strength is likely to decrease over long-term use, and safety may be compromised. Furthermore, if the content of the specific organic compound exceeds 300 ppm by mass, the discoloration resistance and thermal decomposition resistance of the ionomer resin composition are likely to decrease.

[0015] The content of the specific organic compound is preferably 2 ppm by mass or more, more preferably 3 ppm by mass or more, and even more preferably 4 ppm by mass or more, from the viewpoint of easily improving discoloration resistance and glass adhesion. Furthermore, the content of the specific organic compound is preferably 295 ppm by mass or less, more preferably 290 ppm by mass or less, even more preferably 285 ppm by mass or less, still more preferably 280 ppm by mass or less, and particularly preferably 275 ppm by mass or less, from the viewpoint of easily improving transparency and creep resistance. The content of the specific organic compound in the ionomer resin composition can be determined by gas chromatography or the like, for example, by the method described in the Examples.

[0016] The aromatic compound is not particularly limited, and examples thereof include compounds that are liquid at 23° C., such as toluene, xylene, ethylbenzene, cumene, anisole, benzaldehyde, acetophenone, nitrobenzene, aniline, benzonitrile, and styrene. Among these, aromatic hydrocarbons are preferred, and toluene and / or xylene are more preferred, from the viewpoint of easily improving the discoloration resistance, glass adhesion, transparency, and creep resistance of the resulting ionomer resin composition.

[0017] The alcohols are not particularly limited and include, for example, primary alcohols, secondary alcohols, and tertiary alcohols. Among these, from the viewpoint of easily improving the discoloration resistance, transparency, and creep resistance of the resulting ionomer resin composition, primary alcohols are preferred, methanol, ethanol, 1-butanol, and mixtures thereof are more preferred, and ethanol and / or 1-butanol are particularly preferred.

[0018] The organic carboxylic acid is not particularly limited and examples thereof include monocarboxylic acids, dicarboxylic acids, and tricarboxylic acids. Among these, monocarboxylic acids are preferred, and methacrylic acid and / or acrylic acid are more preferred, from the viewpoint of easily improving the discoloration resistance, transparency, and creep resistance of the resulting ionomer resin composition.

[0019] The organic carboxylic acid ester is not particularly limited, and examples thereof include monocarboxylic acid esters, dicarboxylic acid esters, and tricarboxylic acid esters. Among these, from the viewpoint of easily improving the discoloration resistance, transparency, and creep resistance of the resulting ionomer resin composition, monocarboxylic acid esters having 4 to 9 carbon atoms are preferred, and methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, methyl acrylate, ethyl acrylate, n-butyl acrylate, and mixtures thereof are more preferred, and methyl methacrylate, methyl acrylate, and mixtures thereof are even more preferred.

[0020] In a preferred embodiment of the present invention, the specific organic compound is at least one organic compound selected from the group consisting of toluene, xylene, ethanol, 1-butanol, methacrylic acid, acrylic acid, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, methyl acrylate, ethyl acrylate, and n-butyl acrylate.

[0021] [Ionomer Resin] Next, the ionomer resin, which is the other essential component of the ionomer resin composition of the present invention, will be described. The ionomer resin of the present invention 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 (B) is 6 to 10 mol % based on all monomer units constituting the ionomer resin. 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 neutralized unit refers to a structural unit derived from a (meth)acrylic acid neutralized 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.

[0022] If the total content exceeds the upper limit, it is difficult to suppress an increase in melt viscosity during molding of the ionomer resin composition, which may result in a decrease in molding processability of the ionomer resin composition. Furthermore, if the total content is less than the lower limit, the transparency of the ionomer resin composition, particularly the transparency when slowly cooling the ionomer resin to promote crystallization (hereinafter also referred to as "transparency upon slow cooling"), is likely 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 easily improving the transparency (particularly the transparency upon slow cooling) and adhesion to glass of the ionomer resin composition. Furthermore, it is 10 mol% or less, preferably 9.9 mol% or less, and more preferably 9.5 mol% or less, from the viewpoint of easily achieving more favorable molding processability.

[0023] The total content of the units (A) and the units (B) can be adjusted by the preparation method of the ionomer resin. More specifically, when an ionomer resin is prepared using an ethylene-(meth)acrylic acid ester copolymer as a raw material by a method including a saponification reaction step and a demetallization reaction step of the copolymer, the total content can be adjusted by the degree of reaction (conversion rate) of the saponification reaction and the demetallization reaction that convert the (meth)acrylic acid ester units in the ethylene-(meth)acrylic acid ester copolymer into (meth)acrylic acid units (A) and (meth)acrylic acid neutralized units (B). Furthermore, as described in U.S. Pat. No. 8,399,096, when an ionomer resin is produced by polymerizing ethylene and (meth)acrylic acid as raw materials, the total content can be adjusted by the ratio of ethylene and (meth)acrylic acid to be copolymerized.

[0024] <(Meth)acrylic acid unit (A)> 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 glass, methacrylic acid is preferred. The (meth)acrylic acid unit may be a single type or a combination of two or more types.

[0025] The content of the (meth)acrylic acid unit (A) in the ionomer resin is not particularly limited, as long as the total content of the unit (A) and the unit (B) is within the range of 6 to 10 mol % based on all monomer units constituting the ionomer resin. In one embodiment of the present invention, the content of the (meth)acrylic acid unit (A) in the ionomer resin 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, based on all monomer units constituting the ionomer resin, and is 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. When the content of the unit (A) is equal to or greater than the lower limit, the ionomer resin composition is likely to have better transparency and adhesion to glass. When the content is equal to or less than the upper limit, better moldability is likely to be obtained.

[0026] <(Meth)acrylic acid neutralization unit (B)> The (meth)acrylic acid neutralization unit (B) is preferably a neutralization unit of the (meth)acrylic acid unit (A). The (meth)acrylic acid neutralization product is a (meth)acrylic acid 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.

[0027] The content of the (meth)acrylic acid neutralization unit (B) in the ionomer resin is not particularly limited, as long as the total content of the unit (A) and the unit (B) is within the range of 6 to 10 mol % based on all monomer units constituting the ionomer resin. In one embodiment of the present invention, the content of the (meth)acrylic acid neutralization 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 1.6 mol % or more, based on all monomer units constituting the ionomer resin, 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. When the content of the unit (B) is equal to or greater than the lower limit, better transparency and better elastic modulus are easily obtained, and when it is equal to or less than the upper limit, an increase in melt viscosity during molding is easily suppressed.

[0028] When an ionomer resin is prepared using an ethylene-(meth)acrylic acid ester copolymer as a raw material by a method including a saponification reaction step and a demetallization reaction step of the copolymer, the contents of the units (A) and the units (B) can be adjusted by the degree of reaction of the saponification reaction and the demetallization reaction that convert the (meth)acrylic acid ester units in the ethylene-(meth)acrylic acid ester copolymer into (meth)acrylic acid units (A) and (meth)acrylic acid neutralization product units (B).

[0029] <Ethylene Unit (C)> The content of the ethylene unit (C), based on all monomer units constituting the ionomer resin, is preferably 80 mol% or more, more preferably 85 mol% or more, and even more preferably 88 mol% or more, from the viewpoint of easily increasing the mechanical strength (particularly impact resistance) of the ionomer resin composition and easily obtaining better moldability, and is preferably 94 mol% or less, more preferably 92 mol% or less, from the viewpoint of easily increasing the transparency (particularly transparency during slow cooling) of the ionomer resin composition.

[0030] <(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), the ionomer resin in the present invention preferably further contains (meth)acrylic acid ester units (D) from the viewpoint of easily obtaining higher transparency.

[0031] When the ionomer resin contains (meth)acrylic acid ester units (D), the total content of the units (A), (B), and (D) is preferably 6 to 10 mol % based on all monomer units constituting the ionomer resin, from the viewpoint of easily obtaining higher transparency (particularly transparency upon slow cooling). That is, in a preferred embodiment of the present invention, the ionomer resin contains (meth)acrylic acid units (A), (meth)acrylic acid neutralized units (B), ethylene units (C), and (meth)acrylic acid ester units (D), and the total content of the units (A), (B), and (D) is 6 to 10 mol % based on all monomer units constituting the ionomer resin. When the ionomer resin contains (meth)acrylic acid ester units (D), if the total content of the units (A), (B), and (D) is equal to or less than the upper limit, the increase in melt viscosity during molding of the ionomer resin composition is easily suppressed, thereby improving moldability of the ionomer resin composition. Furthermore, if the total content is equal to or greater than the lower limit, the ionomer resin composition is easily able to achieve higher transparency (particularly transparency upon slow cooling). When the ionomer resin contains (meth)acrylic acid ester units (D), the total content of the units (A), (B), and (D) 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 achieving higher transparency (particularly transparency upon slow cooling) and higher adhesion to glass. Furthermore, from the viewpoint of moldability, the total content is 10 mol% or less, preferably 9.9 mol% or less, and more preferably 9.5 mol% or less.

[0032] The total content of the units (A), (B), and (D) can be adjusted by the raw materials of the ionomer resin. More specifically, when an ionomer resin is prepared 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 total content 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. Furthermore, as described in U.S. Pat. No. 8,399,096, when an ionomer resin is prepared by polymerizing ethylene and (meth)acrylic acid as raw materials, the total content can be adjusted by the ratio of ethylene and (meth)acrylic acid to be copolymerized.

[0033] 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, still more preferred monomers are methyl (meth)acrylate, n-butyl (meth)acrylate, and isobutyl (meth)acrylate, and particularly preferred monomer is methyl (meth)acrylate. These monomers may be used alone or in combination of two or more.

[0034] When the ionomer resin contains (meth)acrylic acid ester units (D), the content of the (meth)acrylic acid ester units (D) in the ionomer resin is not particularly limited. In one embodiment of the present invention, the content of the (meth)acrylic acid ester units (D) in the ionomer resin, based on all monomer units constituting the ionomer resin, 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. When the content of units (D) is at least the above-mentioned lower limit and at most the above-mentioned upper limit, the ionomer resin composition is likely to have higher transparency.

[0035] When the ionomer resin 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 in the ethylene-(meth)acrylic acid ester copolymer into (meth)acrylic acid units (A), when the ionomer resin is prepared using 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.

[0036] <Other Monomer Units> The ionomer resin of the present invention may contain other monomer units in addition to the (meth)acrylic acid units (A), (meth)acrylic acid neutralized units (B), and ethylene units (C), as well as the (meth)acrylic acid ester units (D) optionally contained. Examples of other monomer units include carboxylic acid units (A2) other than the (meth)acrylic acid units (A) and carboxylic acid neutralized units (B2) other than the (meth)acrylic acid neutralized units (B). Examples of monomers constituting the carboxylic acid units (A2) include itaconic acid, maleic anhydride, monomethyl maleate, and monoethyl maleate, with monomethyl maleate and monoethyl maleate being preferred. Examples of monomers constituting the carboxylic acid neutralized units (B2) include neutralized units of the carboxylic acid units (A2). Note that carboxylic acid neutralized units are those in which the hydrogen ions of carboxylic acids are replaced with metal ions. The metal ions may be the same as those in the (meth)acrylic acid neutralization unit (B), and the metal ions may be used alone or in combination of two or more. These other monomer units may be used alone or in combination of two or more.

[0037] When the ionomer resin contains the other monomer units, the total content thereof, for example, the total content of (A2) and (B2), may be appropriately selected within a range that does not impair the effects of the present invention. For example, based on all monomer units constituting the ionomer resin, the total content is preferably 5 mol % or less, more preferably 3 mol % or less, and even more preferably 1 mol % or less, and is also preferably 0.01 mol % or more, and more preferably 0.1 mol % or more.

[0038] The contents of the (meth)acrylic acid units (A), (meth)acrylic acid neutralized units (B), and ethylene units (C), as well as the (meth)acrylic acid ester units (D) and other monomer units (e.g., units (A2) and units (B2)) contained in the ionomer resin of the present invention can be determined by first identifying the monomer units in the ionomer resin in the ionomer resin composition by pyrolysis gas chromatography, and then using nuclear magnetic resonance spectroscopy (NMR) and elemental analysis. More specifically, the contents can be determined by the methods described in the Examples. Alternatively, the contents can be determined by a combination of the above analytical methods with IR and / or Raman analysis. Prior to these analyses, it is preferable to remove components other than the ionomer resin by reprecipitation or Soxhlet extraction.

[0039] From the viewpoint of easily improving the discoloration resistance, transparency, and creep resistance of the resulting ionomer resin composition, the content of the ionomer resin is preferably 90% by mass or more, more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more, relative to the total mass of the ionomer resin composition, and is also preferably less than 100% by mass, and more preferably 99.99% by mass or less.

[0040] In one embodiment of the present invention, the degree of branching per 1,000 carbon atoms of the ionomer resin of the present invention is not particularly limited, and is preferably 5 to 30, and more preferably 6 to 20. The degree of branching can be adjusted by the temperature during polymerization of the ionomer resin; for example, when the ionomer resin is prepared 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, by the polymerization temperature during preparation of the ethylene-(meth)acrylic acid ester copolymer. The degree of branching per 1,000 carbon atoms can be measured by the DDMAS method using solid-state NMR.

[0041] In one embodiment of the present invention, the melting point of the ionomer resin is preferably 50°C or higher, more preferably 60°C or higher, and even more preferably 80°C or higher, from the viewpoints of heat resistance and thermal decomposition resistance. Furthermore, from the viewpoint of easily exhibiting adhesive strength with glass when producing laminated glass, the melting point is preferably 200°C or lower, more preferably 180°C or lower, and even more preferably 150°C or lower. The melting point can be measured in accordance with JIS K7121:2012. Specifically, the melting point 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 pick-top temperature of the melting peak during the second heating.

[0042] In one embodiment of the present invention, the heat of fusion of the ionomer resin 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, the heat of fusion 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.

[0043] In one embodiment of the present invention, the MFR of the ionomer resin, measured in accordance with JIS K7210 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, still more preferably 1.0 g / 10 min or more, particularly preferably 1.5 g / 10 min or more, and is preferably 50 g / 10 min or less, more preferably 30 g / 10 min or less, and particularly preferably 10 g / 10 min or less. When the MFR of the ionomer resin is at least the above-mentioned lower limit and at most the above-mentioned upper limit, molding processing is facilitated while suppressing deterioration due to heat, and a resin sheet with excellent penetration resistance is easily obtained.

[0044] The melting point, heat of fusion and MFR of the ionomer resin 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 unit (B), and the ethylene unit (C), as well as the (meth)acrylic acid ester unit (D) that may be contained in the ionomer resin.

[0045] [Additives] The ionomer resin composition of the present invention may further contain additives as necessary. Examples of additives that may be optionally contained include ultraviolet absorbers, antioxidants, antioxidants, heat degradation inhibitors, light stabilizers, anti-sticking agents, lubricants, mold release agents, polymer processing aids, antistatic agents, flame retardants, dyes, pigments, organic dyes, matting agents, and fluorescent materials. Among these additives, ultraviolet absorbers, antioxidants, antioxidants, heat degradation inhibitors, light stabilizers, anti-sticking agents, lubricants, mold release agents, polymer processing aids, and organic dyes are preferred. When the ionomer resin composition contains additives, the additives contained may be one type alone or two or more types in combination.

[0046] When these additives are added, the contents 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 ionomer resin composition.

[0047] The various additives may be added when the ionomer resin composition is produced, may be added after the ionomer resin composition is produced, or may be added when the resin sheet described below is produced.

[0048] The ionomer resin composition of the present invention may be in the form of pellets or the like to improve convenience during storage, transportation, or molding. When pelletizing the ionomer resin composition, for example, pelletization can be performed by cutting strands obtained by melt extrusion. When pelletizing by melt extrusion, the temperature of the ionomer resin composition during melt extrusion is preferably 150°C or higher, more preferably 170°C or higher, from the viewpoint of easily stabilizing discharge from the extruder. Furthermore, the temperature is preferably 250°C or lower, more preferably 230°C or lower, from the viewpoint of easily preventing thermal decomposition and deterioration of the ionomer resin. Because the ionomer resin composition of the present invention has high thermal decomposition resistance, the problem of thermal decomposition of the ionomer resin and changes in its properties is unlikely to occur when pelletizing by melt extrusion.

[0049] [Method for Producing Ionomer Resin Composition] The ionomer resin composition of the present invention can be produced, for example, by (1) a method comprising producing an ionomer resin and mixing the resulting ionomer resin with a specific organic compound, or (2) a method comprising leaving the specific organic compound remaining during the production of the ionomer resin, and optionally mixing the resulting mixture (composition) of the remaining specific organic compound and the ionomer resin with an additional specific organic compound. Method (1) is preferred from the viewpoints of ease of adjusting the proportion of the specific organic compound to a desired value and productivity.

[0050] The method for producing the ionomer resin is not particularly limited. Examples include (I) a method including a step of using an ethylene-(meth)acrylic acid ester copolymer (X) as a raw material and saponifying it (saponification step), and a step of demetallizing at least a portion of the resulting saponified product (demetallization step), and (II) a method including a step of using ethylene and (meth)acrylic acid as raw materials and copolymerizing them (copolymerization step), and a step of partially neutralizing the resulting copolymer (partial neutralization step). For example, the method (II) can be based on the production method described in U.S. Pat. No. 8,399,096. From the viewpoint of easily adjusting the ratio of the specific organic compound to a desired value, method (I) is preferred. Hereinafter, method (I) will be described in detail.

[0051] An example of the method (I) includes a method comprising dissolving the raw material ethylene-(meth)acrylic acid ester copolymer (X) in an organic solvent to obtain an ethylene-(meth)acrylic acid ester copolymer (X) solution (step i), converting all or a part of the (meth)acrylic acid ester units of the ethylene-(meth)acrylic acid ester copolymer (X) in the obtained solution into (meth)acrylic acid neutralized product units by a saponification reaction to obtain a saponified product of the ethylene-(meth)acrylic acid ester copolymer (X) (step ii, saponification step), subjecting the obtained saponified product to a demetallation reaction to convert at least a part of the (meth)acrylic acid neutralized product units (B) into (meth)acrylic acid units (A), thereby obtaining a crude ionomer resin composition containing an ionomer resin and a specific organic compound (step iii, metal removal step), and separating and purifying the crude ionomer resin composition (step iv).

[0052] <Step i)> Examples of monomers constituting the (meth)acrylic acid ester units 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. Of 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, still more preferred monomers are methyl (meth)acrylate, n-butyl (meth)acrylate, and isobutyl (meth)acrylate, and particularly preferred monomer is methyl (meth)acrylate. The monomers may be used alone or in combination of two or more.

[0053] 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, etc. As the copolymer (X), commercially available products may be used, or those synthesized by the high-temperature, high-pressure radical polymerization method described in US 2013 / 0274424, JP 2006-233059, or JP 2007-84743 may also be used. Examples of the commercially available products include "Aclift" (registered trademark) WD301F and WH401F manufactured by Sumitomo Chemical Co., Ltd., and "Rexpearl" (registered trademark) A4250 manufactured by Japan Polyethylene Corporation.

[0054] The content of (meth)acrylic acid ester units 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 is preferably 10 mol% or less, more preferably 9.9 mol% or less, and even more preferably 9.5 mol% or less. The content of (meth)acrylic acid ester units in the copolymer (X) corresponds to the total content of (meth)acrylic acid units (A) and (meth)acrylic acid neutralized units (B), and (meth)acrylic acid ester units (D), if contained, in the ionomer resin in the resulting crude ionomer resin composition and the ionomer resin in the ionomer resin composition. Therefore, when the content of (meth)acrylic acid ester units in the copolymer (X) is at least the above-mentioned lower limit, the ionomer resin composition tends to have higher transparency, particularly transparency during slow cooling, and higher glass adhesiveness. When the content is at most the above-mentioned upper limit, the ionomer resin composition tends to have more suitable moldability. The content of the (meth)acrylic acid ester unit in the copolymer (X) can be adjusted by the copolymerization ratio of ethylene and the (meth)acrylic acid ester. This content can be determined by pyrolysis gas chromatography, nuclear magnetic resonance spectroscopy (NMR) and elemental analysis, similar to the contents of the (meth)acrylic acid unit (A), the (meth)acrylic acid neutralized unit (B), the ethylene unit (C), and the (meth)acrylic acid ester unit (D) if contained, and other monomer units (e.g., the unit (A2) and the unit (B2)) in the ionomer resin described above.

[0055] 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 5 g / 10 min or more, more preferably 10 g / 10 min or more, even more preferably 50 g / 10 min or more, even more preferably 100 g / 10 min or more, and is 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 at least the above-mentioned lower limit and at most the above-mentioned upper limit, the resulting ionomer resin composition is likely to have better moldability and higher strength. The MFR of the ethylene-(meth)acrylic acid ester copolymer (X) can be adjusted by the degree of polymerization and the content of (meth)acrylic acid ester units. The MFR can be measured, for example, by the method described in the Examples.

[0056] From the viewpoint of easily improving the moldability and strength of the resulting ionomer resin composition, 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 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 used 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 Measurements can be performed in polystyrene equivalents using three -H(20)HT columns in series and 1,2,4-trichlorobenzene as the solvent at a column temperature of 140°C.

[0057] The degree of branching per 1000 carbon atoms of the ethylene-(meth)acrylic acid ester copolymer (X) is not particularly limited, and is preferably 5 to 30, more preferably 6 to 20. The degree of branching can be adjusted by the polymerization temperature when polymerizing the copolymer (X). The degree of branching can be adjusted by using the ethylene-(meth)acrylic acid ester copolymer (X) dissolved in deuterated orthodichlorobenzene, １３ It can be measured by carrying out the inverse gate decoupling method of C-NMR.

[0058] The organic solvent for dissolving the ethylene-(meth)acrylic acid ester copolymer (X) is not particularly limited as long as it can dissolve the copolymer (X). Examples of such an organic solvent 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; hydrocarbon compounds such as hexane; acetate esters such as ethyl acetate and methyl acetate; 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; and mixed solvents of aromatic compounds and alcohols. These solvents may be used alone or in combination. Among these, from the viewpoints of solubility and the recoverability of the resulting ionomer resin composition and solvent, aromatic compounds or mixed solvents of aromatic compounds and alcohols are preferred, and aromatic compounds are more preferred.

[0059] The content of the copolymer (X) in the ethylene-(meth)acrylic acid ester copolymer (X) solution obtained in step i) is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 20% by mass or more, and is preferably 80% by mass or less, more preferably 60% by mass or less, even more preferably 40% by mass or less. When the content is equal to or less than the upper limit, the processability is likely to be good and the reaction is easy to control. When the content is equal to or more than the lower limit, the productivity is likely to be high.

[0060] In step i), the temperature at which the ethylene-(meth)acrylic acid ester copolymer (X) is dissolved in the organic solvent is not particularly limited. From the viewpoint of the solubility of the ethylene-(meth)acrylic acid ester copolymer (X), the temperature is preferably 30°C or higher, more preferably 40°C or higher, even more preferably 50°C or higher, and particularly preferably 55°C or higher. The upper limit of the temperature is preferably 120°C or lower, more preferably 100°C or lower, and even more preferably 80°C or lower.

[0061] Step i) may be carried out in air or in an inert gas such as nitrogen gas or argon gas. Step i) may be carried out under normal pressure, elevated pressure, or reduced pressure, and is preferably carried out under elevated pressure.

[0062] <Step ii)> The ethylene-(meth)acrylic acid ester copolymer (X) solution obtained in step i) is mixed with a base to saponify the copolymer (X). Through the saponification reaction, all or a portion of the (meth)acrylic acid ester units in the ethylene-(meth)acrylic acid ester copolymer (X) are converted to (meth)acrylic acid neutralization units, and a saponified ethylene-(meth)acrylic acid ester copolymer (X) containing (meth)acrylic acid neutralization units (B), ethylene units (C), and optionally (meth)acrylic acid ester units (D) is obtained.

[0063] Examples of the base used for saponification include strong bases such as sodium hydroxide, potassium hydroxide, and calcium hydroxide. The bases may be used alone or in combination of two or more. From the viewpoints of solubility in the organic solvent contained in the ethylene-(meth)acrylic acid ester copolymer (X) solution and economy, sodium hydroxide and / or potassium hydroxide are preferred.

[0064] The amount of the base added is preferably 100 to 300 parts by mole, more preferably 120 to 250 parts by mole, and even more preferably 150 to 200 parts by mole, relative to 100 parts by mole of the (meth)acrylic acid ester units of the ethylene-(meth)acrylic acid ester copolymer (X).

[0065] Examples of solvents used for saponification include the same solvents as the organic solvent used to dissolve the ethylene-(meth)acrylic acid ester copolymer (X) in step i). Of these, from the viewpoint of the solubility of the resin before and after the saponification reaction, preferred solvents are mixed solvents of hydrocarbon compounds and alcohols, and mixed solvents of aromatic compounds and alcohols, and more preferred solvents are mixed solvents of aromatic compounds such as toluene and alcohols such as methanol. The ratio of the hydrocarbon compound or aromatic compound to the alcohols in the mixed solvent may be selected appropriately depending on the type of each solvent used, and for example, the mass ratio of the hydrocarbon compound or aromatic compound to the alcohols (hydrocarbon compound or aromatic compound / alcohols) may be 50 / 50 to 90 / 10.

[0066] 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, even more preferably 70° C. or higher, and particularly preferably 80° C. or higher. The upper limit of the temperature is preferably 180° C. or lower, more preferably 150° C. or lower, and even more preferably 120° C. or lower.

[0067] The saponification reaction may be carried out in air or in an inert gas such as nitrogen gas or argon gas, and may be carried out under normal pressure, elevated pressure, or reduced pressure, preferably elevated pressure.

[0068] <Step iii)> The saponified product obtained in step ii) is mixed with an acid to subject the saponified product to a demetallation reaction, which converts at least a portion (step iii-1) or all (step iii-2) of the (meth)acrylic acid neutralization product units (B) in the saponified product of the ethylene-(meth)acrylic acid ester copolymer (X) into (meth)acrylic acid units (A).

[0069] Examples of the acid used in the demetallization reaction include weak acids such as acetic acid, and strong acids such as hydrochloric acid, nitric acid, sulfuric acid, toluenesulfonic acid, etc. Among these, strong acids are preferred from the viewpoint of facilitating washing and removing a salt generated from the base used in the saponification reaction and the acid used in the demetallization reaction, and inorganic acids such as hydrochloric acid, nitric acid, and sulfuric acid are more preferred.

[0070] As examples of the solvent used in the demetallation reaction, the same solvents as those used in the saponification reaction in step ii) can be selected.

[0071] The amount of acid to be added can be selected appropriately in accordance with the amount of strong base to be added in order to adjust the (meth)acrylic acid neutralization product units (B) to any desired value.

[0072] The temperature at which demetallization is carried out is preferably 20°C or higher, more preferably 30°C or higher, even more preferably 40°C or higher, from the viewpoint of easily reducing the viscosity of the reaction solution, and is preferably 180°C or lower, more preferably 150°C or lower, even more preferably 120°C or lower, and particularly preferably 100°C or lower.

[0073] The demetallization may be carried out in air or in an inert gas such as nitrogen gas or argon gas, and may be carried out under normal pressure, elevated pressure, or reduced pressure, preferably under elevated pressure.

[0074] In the case of the step iii-2), i.e., when all of the (meth)acrylic acid neutralized units (B) in the saponified product of the ethylene-(meth)acrylic acid ester copolymer (X) are converted to (meth)acrylic acid units (A) by a demetallation reaction, step iii-2) further includes converting a portion of the (meth)acrylic acid units (A) obtained by the demetallation into (meth)acrylic acid neutralized units (B) by neutralization with a metal ion. The neutralizing agent used in this neutralization step is not particularly limited as long as it is an ionic compound containing a metal ion. Examples of the metal ion include ions of alkali metals such as lithium, potassium, and sodium; ions of alkaline earth metals such as magnesium and calcium; ions of transition metals such as zinc, nickel, iron, and titanium; and aluminum ions. For example, when the metal ion is a sodium cation, examples of the neutralizing agent include sodium hydroxide, sodium acetate, and sodium bicarbonate. Furthermore, polymers such as ionomer resins containing sodium (meth)acrylate units can also be used as the neutralizing agent.

[0075] <Step iv) After step iii), a crude ionomer resin composition containing an ionomer resin and a specific organic compound is separated from the reaction solution obtained and purified to obtain the ionomer resin of the present invention (in the case of the above-mentioned method (1)) or the ionomer resin composition of the present invention (in the case of the above-mentioned method (2)). Separation and purification may be carried out by a conventional method, for example, a separation means such as filtration, washing, concentration, reprecipitation, recrystallization, or silica gel columnography.

[0076] In one embodiment of the present invention, from the viewpoint of facilitating washing and removing a salt that may be a by-product of the base used in the saponification reaction and the acid used in the demetallization reaction (hereinafter also referred to as a "by-product salt"), the separation and purification is preferably carried out by adding a poor solvent to a solution of the crude ionomer resin composition to precipitate a granular material containing the ionomer resin, the by-product salt, and the specific organic compound (hereinafter also simply referred to as a "granular material"), and then washing the precipitated granular material with a washing liquid.

[0077] The solution of the crude ionomer resin composition can be prepared by dissolving the crude ionomer resin composition obtained after step iii) in a solvent. Alternatively, the reaction liquid obtained in step iii) after the demetallization step (step iii-1) or the reaction liquid obtained after the neutralization step (step iii-2) may be used as the solution of the crude ionomer resin composition.

[0078] The solvent for the solution of the crude ionomer resin composition is not particularly limited as long as it is a solvent capable of dissolving the crude ionomer resin composition, and examples thereof include the same solvents as those used in the saponification reaction. Among these, from the viewpoint of the solubility of the crude ionomer resin composition, 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. For example, the mass ratio of the aromatic compound to the alcohol (aromatic compound / alcohol) may be 50 / 50 to 90 / 10, preferably 65 / 35 to 85 / 15.

[0079] The concentration of the crude ionomer resin composition in the solution of the crude ionomer resin composition is preferably 30% by mass or less, more preferably 15% by mass or less, from the viewpoint of easily obtaining granules with a small particle size and easily removing by-product salts, and is also preferably 1% by mass or more, more preferably 5% by mass or more.

[0080] The temperature of the solution of the crude ionomer resin composition is preferably equal to or lower than the melting point of the ionomer resin, more preferably equal to or lower than 60° C., and even more preferably equal to or lower than 50° C., from the viewpoint of easily suppressing aggregation or agglutination of the precipitated particulate matter and easily removing the by-product salt. Furthermore, from the viewpoint of the fluidity of the solution of the crude ionomer resin composition, the temperature is more preferably equal to or higher than 25° C., and even more preferably equal to or higher than 30° C.

[0081] The poor solvent to be added to the solution of the crude ionomer resin composition is not particularly limited, as long as it is a solvent that can be mixed with the solution of the crude ionomer resin composition and does not dissolve the ionomer resin. Examples of poor solvents include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, and 1-butanol; water; ketones such as acetone and methyl ethyl ketone; esters such as methyl acetate and ethyl acetate; ethers such as dimethyl ether, diethyl ether, and tetrahydrofuran; and hydrocarbon compounds such as n-hexane, cyclohexane, and heptane. These solvents may be used alone or in combination of two or more. Among these, from the viewpoints of their low boiling points, which facilitate drying of the ionomer resin or ionomer resin composition in the drying step described below, and of facilitating removal of by-product salts from the granules, the poor solvent is preferably an alcohol such as methanol or 2-propanol, water, or a mixed solvent thereof, and more preferably an alcohol such as methanol.

[0082] The amount of poor solvent added may be selected appropriately depending on the concentration of the crude ionomer resin composition solution. For example, the amount of poor solvent added is preferably 30 parts by mass or more, more preferably 60 parts by mass or more, and particularly preferably 100 parts by mass or more, per 100 parts by mass of the crude ionomer resin composition solution. There is no particular upper limit to the amount of poor solvent added, and the upper limit is usually 1,000 parts by mass or less, per 100 parts by mass of the crude ionomer resin composition solution.

[0083] The method for adding the poor solvent to the solution of the crude ionomer resin composition is not particularly limited. For example, the poor solvent may be added to the solution of the crude ionomer resin composition all at once, or may be added in multiple portions by dropwise addition, etc. From the viewpoint that the particle size of the granules tends to be small, which tends to improve the removability of by-product salts and, as a result, tends to improve the transparency of the resin sheet formed from the resulting ionomer resin composition, the addition of the poor solvent is preferably carried out in a relatively short time, and more preferably added all at once. When the poor solvent is added in multiple portions, it is preferable to complete the addition of the poor solvent within 1 hour, more preferably within 30 minutes, and even more preferably within 10 minutes.

[0084] After adding the poor solvent to the crude ionomer resin composition solution, it is preferable to stir the mixture of the crude ionomer resin composition solution and the poor solvent. The stirring speed is not particularly limited, but the faster the stirring speed, the easier it is to obtain granular particles with a small particle size. The stirring time is not particularly limited, and may be, for example, stirred until granular matter precipitates and the mixture of the crude ionomer resin composition solution and the poor solvent becomes a slurry; specifically, the stirring time is preferably from 1 second to 3 hours, more preferably from 10 seconds to 1 hour, and even more preferably from 1 minute to 30 minutes.

[0085] The peak-top particle size of the granules precipitated by adding a poor solvent to a solution of a crude ionomer resin composition is 700 μm or less, preferably 650 μm or less, more preferably 600 μm or less, and even more preferably 550 μm or less, from the viewpoint of easily removing by-product salts from the granules by increasing the specific surface area of ​​the granules and easily removing specific organic compounds from the granules almost completely (to below the detection limit). Furthermore, from the viewpoint of easily improving the filterability of the granules and easily improving the production efficiency of the ionomer resin composition, it is preferably 50 μm or more, more preferably 70 μm or more, and preferably 80 μm or more. The peak-top particle size can be measured, for example, by laser diffraction / scattering or single light scattering.

[0086] The peak-top particle size of the granules precipitated by adding a poor solvent to a solution of a crude ionomer resin composition can be adjusted by the concentration and temperature of the solution of the crude ionomer resin composition. Specifically, lowering the concentration and / or temperature of the solution of the crude ionomer resin composition reduces the peak-top particle size of the precipitated granules, while increasing the concentration and / or temperature of the solution of the crude ionomer resin composition increases the peak-top particle size of the precipitated granules. The peak-top particle size of the granules can also be adjusted by the method of adding the poor solvent and the stirring speed of the mixture of the solution of the crude ionomer resin composition and the poor solvent.

[0087] The washing liquid used to wash the precipitated particulate matter is not particularly limited as long as it is a solvent in which the ionomer resin or ionomer resin composition does not dissolve. Preferred examples of washing 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.

[0088] Among these cleaning solutions, alcohols, water, and mixtures thereof are preferred from the viewpoint of ease of removing by-product salts and specific organic compounds. Furthermore, a more preferred cleaning solution is a mixture of water and alcohols from the viewpoint of making the specific gravity of the cleaning solution smaller than that of the granules, thereby increasing the contact area between the cleaning solution and the granules and thereby improving the removability of by-product salts; of making it easier to adjust the content of specific organic compounds in the ionomer resin or ionomer resin composition obtained after washing to within a desired range; and / or of making it easier to dry the ionomer resin or ionomer resin composition obtained after washing. Preferred alcohols are methanol and ethanol, more preferably methanol, because they are easy to dry and have high compatibility with water. The ratio of water to alcohols (water / alcohols (mass%)) in the mixture of water and alcohols is preferably 20 / 80 to 80 / 20, more preferably 30 / 70 to 70 / 30.

[0089] An example of a method for washing granular materials with a washing solution includes filtering the granular materials from a granular material dispersion in which the granular materials have precipitated, mixing the filtered granular materials with the washing solution, and then draining the liquid. More specifically, a washing method includes mixing the granular materials filtered from the granular material dispersion with the washing solution, filtering the granular materials from the washing solution (hereinafter also referred to as washing step (a)), mixing the filtered granular materials with new washing solution, and filtering the granular materials from the washing solution (hereinafter also referred to as washing step (b)). From the viewpoints of ease of removing by-product salts and specific organic compounds contained in the granular materials and production efficiency, in the case of a batch process, the washing of the granular materials is preferably performed, for example, once in washing step (a), followed by washing step (b), preferably 1 to 10 times, more preferably 1 to 8 times, and even more preferably 1 to 6 times. The content of organic carboxylic acids and / or organic carboxylic acid esters (specific organic compounds) in the granular materials can be adjusted by the number of washings. For example, by carrying out the washing step (b) preferably 4 to 10 times, more preferably 6 to 8 times, the content of organic carboxylic acid and / or organic carboxylic acid ester in the washed granules can be adjusted to less than 1 ppm by mass. Also, by carrying out the washing step (b) preferably 1 to 3 times, more preferably 1 to 2 times, the content of organic carboxylic acid and / or organic carboxylic acid ester in the washed granules can be adjusted to 1 ppm by mass or more and 300 ppm by mass.

[0090] The amount of the cleaning solution used per washing step may be appropriately selected depending on the amount of granular material to be washed. For example, the amount of the cleaning solution used per washing step is preferably 100 to 2,000 parts by mass, more preferably 200 to 1,000 parts by mass, and even more preferably 300 to 700 parts by mass, per 100 parts by mass of the granular material on a dry basis.

[0091] The washed granules are preferably dried. When drying is performed, the temperature is preferably below the melting point of the ionomer resin, more preferably below 80°C. When drying is performed, drying may be performed under normal pressure, increased pressure, or reduced pressure, and is preferably performed under reduced pressure. The content of aromatic compounds and / or alcohols (specific organic compounds) in the granules can be adjusted by adjusting the drying conditions. For example, by drying under vacuum for 24 hours or more, the content of aromatic compounds and / or alcohols in the dried granules can be adjusted to less than 1 ppm by mass. Furthermore, for example, by drying under vacuum for 1 hour to about 8 hours, the content of aromatic compounds and / or alcohols in the dried granules can be adjusted to 1 ppm by mass or more and 300 ppm by mass.

[0092] In the case of method (1) and method (2), the content of the specific organic compound in the granules can be adjusted by mixing the dried granules with a specific organic compound as needed. From the viewpoints of ease of adjusting the content of the specific organic compound to a desired value, as well as productivity and quality stability, it is preferable that the content of the specific organic compound in the dried granules is substantially zero (e.g., below the detection limit (0.1 ppm by mass)) (i.e., the dried granules are an ionomer resin, not an ionomer resin composition containing an ionomer resin and a specific organic compound), and the content of the specific organic compound in the granules is adjusted to 1 ppm by mass or more and 300 ppm by mass by mixing the granules with the specific organic compound. The mixing method is not particularly limited. For example, mixing may be performed using a batch-type melt kneader, a vented single-screw extruder, or a vented twin-screw extruder. From the viewpoint of quality stability, the mixing temperature is preferably 220°C or less, more preferably 210°C or less, and even more preferably 200°C or less. From the viewpoint of productivity, the mixing temperature is preferably 160°C or higher, more preferably 170°C or higher, and even more preferably 180°C or higher. The dispersion state of the specific organic compound in the ionomer resin composition is not particularly limited, but from the viewpoint of easily achieving the effects of the present invention, it is preferable that the specific organic compound be uniformly dispersed in the ionomer resin composition. Therefore, mixing is preferably carried out until a homogeneous ionomer resin composition is obtained.

[0093] <Characteristics of Ionomer Resin Composition> The ionomer resin composition of the present invention has excellent transparency. The haze of a sheet of the ionomer resin composition of the present invention at a thickness of 0.8 mm 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 composition, the lower limit is not particularly limited and may be, for example, 0.01%. The haze of the ionomer resin composition is measured, for example, using a haze meter in accordance with JIS K7136:2000.

[0094] According to the inventors' investigations, if the crystallinity of an ionomer resin is too high, the ionomer resin tends to whiten. Therefore, normally, when an ionomer resin is slowly cooled to promote its crystallization, its transparency (transparency upon slow cooling) tends to decrease. However, the ionomer resin of the present invention has a total content of (meth)acrylic acid units (A) and (meth)acrylic acid neutralized units (B) of 6 mol % or more, so the resin is less likely to crystallize even upon slow cooling. As a result, the ionomer resin composition of the present invention, which contains such an ionomer resin, can maintain high transparency even after the crystallization of the ionomer resin has been promoted by slow cooling. The haze (slow cooling haze) of the ionomer resin composition of the present invention after the crystallization of the ionomer resin has been promoted by slow cooling is preferably 5.0% or less, more preferably 4.5% or less, even more preferably 4.0% or less, even more preferably 3.0% or less, and particularly preferably 2.5% or less. Since the smaller the haze, the higher the transparency of the ionomer resin composition, the lower limit is not particularly limited and may be, for example, 0.01%. The annealed haze can be measured by placing a 0.8 mm-thick sheet of the ionomer resin composition between two glass plates to prepare a laminated glass, 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 measuring the haze after that using a haze meter in accordance with JIS K7136:2000.

[0095] The ionomer resin composition of the present invention has excellent discoloration resistance and is less likely to discolor during molding. From the viewpoint of easily improving discoloration resistance, the yellowness index (YI) of a sheet of the ionomer resin composition of the present invention at a thickness of 0.8 mm is preferably 1.1 or less, more preferably 0.9 or less, and even more preferably 0.7 or less. Since the smaller the yellowness index (YI), the higher the discoloration resistance of the ionomer resin composition, 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, for example, by the method described in the Examples.

[0096] The adhesion between the ionomer resin composition of the present invention and glass can be evaluated by the peel energy between the ionomer resin composition and glass measured by a peel test. The peel energy between the ionomer resin composition and glass measured under standard conditions (23°C, 50% RH) is preferably 2.0 kJ / m ２ More preferably, 2.5 kJ / m ２ More preferably, 3.0 kJ / m ２ More preferably, 3.5 kJ / m ２ The adhesion between the ionomer resin composition and glass under high humidity conditions can be evaluated by the peel energy between the ionomer resin composition and glass measured by a peel test under wet conditions. This peel energy is preferably 0.05 kJ / m ２ More preferably, 0.10 kJ / m ２ More preferably, 0.15 kJ / m ２ More preferably, 0.17 kJ / m ２ More preferably, 0.20 kJ / m ２ The upper limit of the peel energy under standard conditions and high humidity conditions is not particularly limited, and is 10 kJ / m ２ The peel test can be carried out, for example, by the method described in International Publication No. 2019-027865 as a peel adhesion measurement method. The peel energy measured under the standard conditions and wet conditions can be measured, for example, by the method described in the Examples.

[0097] The ionomer resin composition of the present invention has sufficient creep resistance. Therefore, when a resin sheet having one or more layers containing the ionomer resin composition of the present invention is used as an interlayer film for laminated glass, as described below, the strength is unlikely to decrease even after long-term use, making it easier to ensure safety. The creep resistance of the ionomer resin composition can be measured by the relaxation modulus after a long period of time (long-term relaxation modulus), for example, a value of 2.6 × 10 when a master curve is created at 50°C. ６In one embodiment of the present invention, the relaxation modulus of 2.6 × 10 when a master curve was created at 50°C can be evaluated by the relaxation modulus after 10 seconds (about 1 month). ６ The relaxation modulus after 10 seconds is preferably 0.40 MPa or more, more preferably 0.45 MPa or more, and even more preferably 0.50 MPa or more, from the viewpoint of easily increasing the creep resistance of the ionomer resin composition. Furthermore, from the viewpoint of ease of handling of the resin sheet, the relaxation modulus may be 5.0 MPa or less, preferably 2.5 MPa or less. The relaxation modulus can be determined by leaving a resin sheet made of the ionomer resin composition at rest in an atmosphere of 23°C and 50% RH for one week or more, and then measuring the resin sheet using a dynamic viscoelasticity measuring device, and then determining the relaxation modulus from a composite curve (referred to as a master curve) at a reference temperature of 50°C obtained from dynamic viscoelasticity measurement and the time-temperature conversion rule, for example, by the method described in the Examples.

[0098] [Resin Sheet] The present invention also relates to a resin sheet having one or more layers (hereinafter also referred to as layer (x)) containing the ionomer resin composition of the present invention. In one embodiment of the present invention, the layer (x) is composed of the ionomer resin composition of the present invention. The resin sheet of the present invention may be composed of only one layer (x), or may be a laminate containing at least one layer (x). The configuration of the laminate is not particularly limited. Examples include a laminate consisting of two or more layers (x), and a laminate containing one or more layers (x) and one or more other layers. When the laminate contains multiple layers (x) or multiple other layers, the resins or resin compositions constituting each layer (x) or each other layer may be the same or different.

[0099] The other layer can be a layer containing a known resin.Examples of the resin include polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyurethane, polytetrafluoroethylene, acrylic resin, polyamide, polyacetal, polycarbonate, polyesters such as polyethylene terephthalate, polybutylene terephthalate, cyclic polyolefin, polyphenylene sulfide, polysulfone, polyethersulfone, polyarylate, liquid crystal polymer, polyimide, and thermoplastic elastomer.Furthermore, the other layer may contain one or more additives such as the additives exemplified in the above [Additives] section, as well as plasticizers, heat-shielding materials (for example, inorganic heat-shielding particles or organic heat-shielding materials having infrared absorption ability), and functional inorganic compounds, if necessary.

[0100] In a preferred embodiment of the present invention, from the viewpoint of excellent degassing properties when the resin sheet and glass are thermocompression-bonded, the resin sheet of the present invention preferably has an uneven structure on at least one surface, preferably both surfaces, which is imparted by a conventionally known method such as a melt fracture method or an embossing method. The shape of the melt fracture and embossing is not particularly limited, and conventionally known shapes may be appropriately selected.

[0101] The thickness of one 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 contains multiple layers (x), the thicknesses of the layers (x) may be the same or different.

[0102] 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, still 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 particularly preferably 0.75 mm or more, and is also 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.

[0103] 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 in a roll or in a state of being individual sheets.

[0104] In one embodiment of the present invention, the content of the ionomer resin composition of the present invention contained in the resin sheet of the present invention is preferably 90% by mass or more, more preferably 93% by mass or more, even more preferably 95% by mass or more, still more preferably 98% by mass or more, and preferably 100% by mass or less, relative to the mass of the resin sheet, from the viewpoint of easily improving the transparency, discoloration resistance, and creep resistance of the resulting resin sheet.

[0105] The resin sheet of the present invention has excellent transparency, transparency upon annealing, coloration resistance, adhesion to glass (under standard conditions and wet conditions), and thermal decomposition resistance, and also has sufficient creep resistance, due to the properties of the ionomer resin composition of the present invention. In a preferred embodiment of the present invention, the resin sheet of the present invention has haze, annealing haze, yellowness index, adhesion to glass, thermal decomposition resistance, and creep resistance equivalent to those of the ionomer resin composition of the present invention.

[0106] [Method for Producing Resin Sheet] The method for producing the resin sheet of the present invention is not particularly limited. For example, after uniformly kneading the ionomer resin composition of the present invention, the layer (x) can be produced by a known film-forming method such as extrusion, calendaring, pressing, solution casting, melt casting, or inflation. The layer (x) may be used alone as a resin sheet. Alternatively, 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 obtain a laminate, or two or more layers (x), or one or more layers (x) and one or more other layers may be molded by co-extrusion to obtain a laminate, which may then be used as a resin sheet. When the laminate contains multiple layers (x) or multiple other layers, the resins or resin compositions constituting each layer (x) or each other layer may be the same or different.

[0107] Among known film-forming methods, a method of producing a resin sheet using an extruder is preferably used. The resin temperature or resin composition temperature during extrusion is preferably 150°C or higher, more preferably 170°C or higher, from the viewpoint of facilitating stabilization of resin discharge from the extruder and reducing mechanical troubles. The temperature is preferably 250°C or lower, more preferably 230°C or lower, from the viewpoint of facilitating reduction of resin decomposition and degradation of the resin associated with decomposition. In addition, in order to efficiently remove volatile substances, it is preferable to remove the volatile substances from a vent port of the extruder by reducing pressure.

[0108] [Laminated Glass Interlayer Film and Laminated Glass] The resin sheet of the present invention can be suitably used as a laminated glass interlayer film (also simply referred to as an interlayer film). Accordingly, the present invention encompasses a laminated glass interlayer film made of the resin sheet of the present invention. The present invention also encompasses laminated glass having two glass plates and a laminated glass interlayer film of the present invention disposed between the two glass plates. Because the laminated glass of the present invention has a laminated glass interlayer film made of the resin sheet, it can have excellent transparency and coloration resistance, and has excellent adhesion between the interlayer film and the glass.

[0109] The glass plates to be laminated with the interlayer film of the present invention may be, for example, inorganic glass such as float glass, polished plate glass, figured glass, wired plate glass, or heat-absorbing plate glass, as well as conventionally known organic glass such as polymethyl methacrylate or polycarbonate. These may be either colorless or colored. One type of these may be used, or two or more types may be used in combination. Furthermore, 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.

[0110] The laminated glass of the present invention can be produced by a conventionally known method. Examples of such methods include a method using a vacuum laminator, a method using a vacuum bag, a method using a vacuum ring, and a method using nip rolls. Another method involves pressure bonding using the above methods, followed by placing the glass in an autoclave for further bonding.

[0111] When using a vacuum laminator, for example, 1 × 10 －６ ~1 x 10 －１ Laminated glass can be produced by laminating glass sheets, an interlayer film, and an optional layer (such as an adhesive resin layer) under a reduced pressure of 60 to 200°C, particularly 80 to 160°C, of ​​a pressure of about 2 × 10 MPa. A method using a vacuum bag or a vacuum ring is described, for example, in European Patent No. 1235683. －２ ~3 x 10 －２ A laminated glass can be produced by laminating a glass plate and an interlayer film at 100 to 160° C. under a reduced pressure of about 100 MPa.

[0112] An example of a manufacturing method using nip rolls is a method in which a glass plate, an interlayer film, and any optional layers are laminated, degassed with rolls at a temperature below the flow initiation temperature of the interlayer film, and then pressure-bonded at a temperature close to the flow initiation temperature. Specifically, for example, a method in which the laminate is heated to 30 to 70°C using an infrared heater or the like, degassed with rolls, further heated to 50 to 120°C, and then pressure-bonded with rolls is exemplified.

[0113] When the laminated glass is placed in an autoclave and further pressure-bonded, 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.

[0114] The laminated glass of the present invention is excellent in transparency, transparency during annealing, coloration resistance, and adhesion to glass (under standard conditions and wet conditions), and also has sufficient creep resistance, due to the properties of the ionomer resin composition of the present invention. In a preferred embodiment of the present invention, the laminated glass of the present invention has haze, annealing haze, yellowness index, adhesion to glass, and creep resistance equivalent to those of the ionomer resin composition of the present invention.

[0115] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0116] [Content of Monomer Units in Raw Material Resin and Ionomer Resin] [Raw Material Resin] The ethylene-(meth)acrylic acid ester copolymer (X) used as a raw material in the Examples and Comparative Examples was dissolved in deuterated toluene or deuterated THF, １ The content of each monomer unit was determined using H-NMR (400 MHz, manufactured by JEOL Ltd.).

[0117] [Ionomer Resin] The ionomer resin compositions obtained in the Examples and Comparative Examples were analyzed for the contents of (meth)acrylic acid units (A), (meth)acrylic acid neutralized units (B), ethylene units (C), and (meth)acrylic acid ester units (D) in the ionomer resin as follows. The ionomer resin compositions obtained in the Examples and Comparative Examples were each dissolved in a mixed solvent of dehydrated toluene and dehydrated acetic acid (75 / 25% by mass), reacted at 100°C for 2 hours, and then reprecipitated in a mixed solvent of acetone and water (80 / 20% by mass), thereby converting the (meth)acrylic acid neutralized units (B) into (meth)acrylic acid units (A). The resulting mixture was then thoroughly washed with water and dried, after which the following steps (1) to (3) were carried out. (1) The components of the monomer units constituting 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, １ H-NMR (400 MHz, manufactured by JEOL Ltd.) measurements were performed. (4) Furthermore, the ionomer resin compositions obtained in the examples and comparative examples were each subjected to microwave decomposition pretreatment with nitric acid, followed by ICP emission spectrometry (Thermo Fisher Scientific iCAP6500Duo) to identify the type and amount of metal ions in the (meth)acrylic acid neutralization unit (B). From the information in (1) above, the type and structure of the (meth)acrylic acid ester unit (D) and the (meth)acrylic acid unit (A) were identified. From this information and the information in (2) and (3) above, the ratio of ethylene unit (C) / (meth)acrylic acid ester unit (D) / (total of (meth)acrylic acid unit (A) and (meth)acrylic acid neutralization unit (B)) was calculated. Furthermore, 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 from the information in (4) above.

[0118] [Content of specific organic compounds in ionomer resin compositions and resin sheets] The content of specific organic compounds in the ionomer resin compositions and resin sheets obtained in the examples and comparative examples was quantified by multiple headspace gas chromatography mass spectrometry (MHE-GC / MS). Specifically, using a headspace apparatus G1888 (manufactured by Agilent Technologies) and a gas chromatograph mass spectrometer 6890N 5975C inert MDS (manufactured by Agilent Technologies), 0.1 g of each freeze-pulverized sample was measured by the detection method SIM under the following conditions, and data was obtained using an MSD as a detector. Headspace conditions: heating temperature 120°C, heating time 30 minutes. GC conditions: column; DB-WaxUI (30 m-0.25 mm-0.5 μm), oven; held at 40°C for 5 minutes, then heated to 240°C at 10°C / min and held at 240°C for 15 minutes, injection port; 200°C, split injection (20:1). Five consecutive measurements were performed, and the sum of the peak areas of the target components was calculated by simulation from the obtained data. For compounds that did not reach gas-solid equilibrium under the above conditions, quantification was performed using the single-point calibration method from the peak areas obtained from the first measurement.

[0119] [Water Content in Ionomer Resin Composition and Resin Sheet] The water content of the ionomer resin composition and resin sheet obtained in Comparative Example 2 was quantified by Karl Fischer titration. Specifically, a moisture vaporizer VA-121 (manufactured by Mitsubishi Chemical Corporation) and a trace moisture analyzer CA-200 (manufactured by Mitsubishi Chemical Corporation) were used, and 1 g of each sample was placed on a quartz cell in the furnace of the moisture vaporizer, and heated at 200°C. The generated water vapor was introduced into the electrolytic cell of the trace moisture analyzer by nitrogen gas, and the moisture content was measured.

[0120] [Thermal Decomposition Resistance] The thermal decomposition resistance of the ionomer resin compositions obtained in the Examples and Comparative Examples was evaluated in accordance with JIS K7120:1987. Specifically, using a simultaneous thermogravimetry and differential thermal analyzer TG-DTA7200 (manufactured by Hitachi High-Tech Science Corporation), the weight loss rate was measured when each resin sheet prepared from each resin composition was heated from 20°C to 550°C under a nitrogen atmosphere at a heating rate of 10°C / min and a flow rate of 50 mL / min. The 1% weight loss temperature (Td1), which is the temperature at which the weight loss rate becomes 1% based on the weight at 200°C, was used as an index of thermal decomposition resistance.

[0121] [Yellowness Index (YI)] Each of the resin sheets obtained in the examples and comparative examples was measured in accordance with JIS Z8722 using a colorimeter "ZE-2000" (manufactured by Nippon Denshoku Industries Co., Ltd.) The yellowness index value calculated in accordance with JIS K7373 using the obtained values ​​was adopted as the yellowness index (YI) of the resin sheet.

[0122] [Creep Resistance] Each resin sheet obtained in the Examples and Comparative Examples was left standing for at least one week in an atmosphere of 23°C and 50% RH. Next, a test piece measuring 40 mm long x 5 mm wide was cut out from each resin sheet. The obtained test piece was placed in a dynamic viscoelasticity measuring device (manufactured by UBM Co., Ltd.), and dynamic viscoelasticity measurements were performed in tension mode at temperatures of 50 to 100°C and frequencies of 0.1, 0.5, 1, 5, 10, 50, and 100 Hz according to a method in accordance with JIS K 0129:2005. From the obtained storage modulus measurement results, a composite curve (master curve) at a reference temperature of 50°C was created using the temperature-time conversion rule. From this composite curve, a frequency of 4.0 x 10 －７ Storage modulus (E'(t1)) in Hz and frequency 2.0 x 10 －７ The loss modulus (E''(t)) was measured at 50°C and 2.6 x 10 Hz. The Poisson's ratio was fixed at 0.5, and the loss modulus was calculated using the following formula (A). ６ The relaxation modulus G(t) after 10 seconds was determined and this value was used as an index of creep resistance: G(t) = E'(t1) / 3 - 0.4 × E''(t2) / 3 Formula (A) This series of calculations was performed using the calculation software "RheoStation" (manufactured by UBM Co., Ltd.) that comes with the dynamic viscoelasticity measuring device.

[0123] [Transparency upon annealing (annealing haze)] Each resin sheet obtained in the examples and comparative examples was cut into a 30 cm square, sandwiched between two 30 cm square 2.7 mm thick float glass sheets, and placed in a vacuum laminator (1522N manufactured by Nisshinbo Mechatronics Inc.). The pressure inside the vacuum laminator was reduced to 100 ° C. for 1 minute, and the laminate was pressed at 30 kPa for 5 minutes while maintaining the reduced pressure and temperature to obtain a temporary bonded body. The resulting temporary bonded body was placed in an autoclave and treated at 140 ° C. and 1.2 MPa for 30 minutes to obtain a laminated glass. The resulting laminated glass was heated to 140 ° C. and then annealed to 23 ° C. at a rate of 0.1 ° C. / min. The haze of the laminated glass after annealing was measured in accordance with JIS K7136:2000 using a haze meter HZ-1 (manufactured by Suga Test Instruments Co., Ltd.).

[0124] [Appearance Evaluation of Resin Sheet and Laminated Glass] For each resin sheet obtained in the Examples and Comparative Examples, a 30 cm square region near the center of the resin sheet was designated as an appearance evaluation observation region. The region was visually observed to check for the presence or absence of gelled matter and air bubbles in the resin sheet, and evaluated according to the following criteria. In addition, laminated glass (30 cm square) obtained in the same manner as above was visually observed to check for the presence or absence of gelled matter and air bubbles in the laminated glass, and evaluated according to the following criteria. A: Fewer than 5 gelled matter and air bubbles were observed. B: 5 or more gelled matter and air bubbles were observed. In the above criteria, a rating of A means that the appearance of the resin sheet or laminated glass is good.

[0125] [Adhesion to Glass Under Standard Conditions (Dry Conditions)] The peel strength P of the laminated glass obtained in the same manner as described above was measured according to the method described as a peel adhesion measurement method in WO 2019 / 027865. Ｄｒｙ Specifically, a peel test was performed in a 90° direction at a speed of 1 cm / min under conditions of 23°C and 50% RH using a universal testing machine (MTS Criterion M45). Ｄｒｙ and the width W of the peel test piece, the peel energy γ Ｄｒｙwas calculated using the following formula: γ Ｄｒｙ [kJ / m ２ ]=P Ｄｒｙ [kJ / m] / W[m]

[0126] [Adhesion to Glass Under Wet Conditions] Adhesion to glass under high humidity conditions was evaluated by measuring the peel energy under wet conditions using the following method. For laminated glass obtained in the same manner as described above, the peel force P Ｗｅｔ Specifically, a peel test was performed in a 90° direction at a speed of 1 cm / min under conditions of 23°C and 50% RH using a universal testing machine (MTS Criterion M45), and when the test piece had peeled 100 mm, water was dropped between the glass and the peeled surface to make the peeled surface wet, and then peeling was resumed at a speed of 0.025 cm / min, and the peel force P in the wet state was measured. Ｗｅｔ The peel force P Ｗｅｔ and the width W of the peel test piece, the peel energy γ Ｗｅｔ was calculated using the following formula: γ Ｗｅｔ [kJ / m ２ ]=P Ｗｅｔ [kJ / m] / W[m]

[0127] [Raw Material Resin] In the Examples and Comparative Examples, the amount of methyl methacrylate (MMA) modification or the amount of ethyl acrylate (EA) modification, and MFR of each ethylene-(meth)acrylic acid ester copolymer (X) used as a raw material for the ionomer resin are shown in Table 1. "Aclift" (registered trademark) WH401F manufactured by Sumitomo Chemical Co., Ltd. was used as EMMA1, and "Rexpearl" (registered trademark) A4250 manufactured by Japan Polyethylene Corporation was used as EEA1. The MFR was measured in accordance with JIS K7210-1:2014. Specifically, each raw material resin was melted in a cylinder and extruded through 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. The amount of resin extruded per 10 minutes (g / 10 min) was measured, and this value was used as the MFR.

[0128]

[0129] Example 1: 100 parts by mass of EMMA2 listed in Table 1 was introduced into a reaction vessel, and 233 parts by mass of toluene was added thereto. The mixture was stirred at 60°C under a pressure of 0.02 MPa to dissolve the EMMA2. 100 parts by mass of a 20% by mass solution of sodium hydroxide in methanol was added to the resulting solution, and the mixture was stirred at 100°C for 4 hours to saponify the EMMA2 and convert some of the methyl methacrylate units to sodium methacrylate units. The solution was then cooled to 50°C, and 83 parts by mass of 20% by mass of hydrochloric acid was added to the reaction solution. The mixture was stirred at 50°C for 1 hour to convert some of the sodium methacrylate units to methacrylic acid, yielding a solution containing an ionomer resin. A mixed solvent of toluene / methanol (75 / 25% by mass) was added to the resulting solution to adjust the ionomer resin concentration to 10% by mass, thereby diluting the solution. The resulting diluted solution containing the ionomer resin was then adjusted to 34°C, and 430 parts by weight of 34°C methanol was added to the diluted solution per 100 parts by weight of the solution containing the ionomer resin to precipitate granules containing the ionomer resin. The resulting granules were then filtered, and 100 parts by weight of the filtered granules were mixed with 600 parts by weight of a water / methanol (50 / 50% by weight) mixed solvent. The resulting slurry was stirred at 40°C for 1 hour, and then the granules were filtered at room temperature. The granules were washed six more times with the water / methanol mixed solvent and then vacuum-dried for 24 hours or more to obtain a granular ionomer resin. 100 parts by weight of the resulting granular ionomer resin and 0.0015 parts by weight of toluene were melt-kneaded in a batch melt-kneader at 210°C and 90 rpm for 3 minutes to obtain an ionomer resin composition. Thereafter, the obtained ionomer resin composition was heated at 210°C and subjected to a pressure of 4.9 MPa (50 kgf / cm ２ The mixture was compression molded at a pressure of 100 psi for 5 minutes to obtain a resin sheet having a thickness of 0.8 mm. The ionomer resin, ionomer resin composition, and resin sheet were analyzed and evaluated. The results are shown in Table 2.

[0130] [Example 2] An ionomer resin, an ionomer resin composition, and a resin sheet were obtained, and analyzed and evaluated in the same manner as in Example 1, except that EMMA3 was used instead of EMMA2, and 0.0045 parts by mass of xylene was used instead of 0.0015 parts by mass of toluene during melt-kneading. The results are shown in Table 2.

[0131] [Example 3] An ionomer resin, an ionomer resin composition, and a resin sheet were obtained, and analyzed and evaluated in the same manner as in Example 1, except that EMMA3 was used instead of EMMA2, and 0.0008 parts by mass of methacrylic acid was used instead of 0.0015 parts by mass of toluene during melt-kneading. The results are shown in Table 2.

[0132] [Example 4] An ionomer resin, an ionomer resin composition, and a resin sheet were obtained, and analyzed and evaluated in the same manner as in Example 1, except that EMMA3 was used instead of EMMA2, and 0.0003 parts by mass of methyl methacrylate was used instead of 0.0015 parts by mass of toluene during melt-kneading. The results are shown in Table 2.

[0133] [Example 5] An ionomer resin, an ionomer resin composition, and a resin sheet were obtained, and analyzed and evaluated in the same manner as in Example 1, except that EEA1 was used instead of EMMA2, and 0.0075 parts by mass of methyl acrylate was used instead of 0.0015 parts by mass of toluene during melt-kneading. The results are shown in Table 2.

[0134] [Example 6] An ionomer resin, an ionomer resin composition, and a resin sheet were obtained, and analyzed and evaluated in the same manner as in Example 1, except that EMMA1 was used instead of EMMA2, the amounts of the methanol solution of sodium hydroxide (20% by mass) and hydrochloric acid (20% by mass) added were changed to 80 parts by mass and 66 parts by mass, respectively, and 0.0300 parts by mass of methanol was used instead of 0.0015 parts by mass of toluene during melt-kneading. The results are shown in Table 2.

[0135] [Example 7] An ionomer resin, an ionomer resin composition, and a resin sheet were obtained, and analyzed and evaluated in the same manner as in Example 1, except that EEA1 was used instead of EMMA2, and 0.0030 parts by mass of acrylic acid was used instead of 0.0015 parts by mass of toluene during melt-kneading. The results are shown in Table 2.

[0136] [Example 8] An ionomer resin, an ionomer resin composition, and a resin sheet were obtained, and analyzed and evaluated in the same manner as in Example 1, except that 0.0350 parts by mass of toluene was used instead of 0.0015 parts by mass of toluene during melt-kneading. The results are shown in Table 2.

[0137] [Example 9] An ionomer resin, an ionomer resin composition, and a resin sheet were obtained, and analyzed and evaluated in the same manner as in Example 1, except that EMMA3 was used instead of EMMA2, and 0.0340 parts by mass of methanol was used instead of 0.0015 parts by mass of toluene during melt-kneading. The results are shown in Table 2.

[0138] Comparative Example 1 An ionomer resin and a resin sheet were obtained, and analyzed and evaluated in the same manner as in Example 6, except that methanol was not used during melt-kneading. The results are shown in Table 2.

[0139] [Comparative Example 2] An ionomer resin, an ionomer resin composition, and a resin sheet were obtained, and analyzed and evaluated in the same manner as in Example 6, except that 0.0380 parts by mass of water was used instead of 0.03 parts by mass of methanol during melt-kneading. The results are shown in Table 2.

[0140] [Comparative Example 3] An ionomer resin, an ionomer resin composition, and a resin sheet were obtained, and analyzed and evaluated in the same manner as in Example 2, except that 0.1200 parts by mass of methacrylic acid was used instead of 0.0045 parts by mass of xylene during melt-kneading. The results are shown in Table 2.

[0141] [Comparative Example 4] An ionomer resin, an ionomer resin composition, and a resin sheet were obtained, and analyzed and evaluated in the same manner as in Example 1, except that EMMA4 was used instead of EMMA2, the amounts of the methanol solution of sodium hydroxide (20% by mass) and hydrochloric acid (20% by mass) added were changed to 72 parts by mass and 59 parts by mass, respectively, and 0.0120 parts by mass of methanol was used instead of 0.0015 parts by mass of toluene during melt-kneading. The results are shown in Table 2.

[0142]

[0143] As shown in Table 2, the ionomer resin compositions obtained in Examples 1 to 9 were confirmed to have high transparency and glass adhesion and low discoloration. The ionomer resin compositions obtained in Examples 1 to 9 were also confirmed to have high thermal decomposition resistance and sufficient creep resistance. In contrast, the ionomer resin obtained in Comparative Example 1 and the ionomer resin compositions obtained in Comparative Examples 2 to 4 were inferior in at least one of transparency, glass adhesion, and discoloration resistance.

[0144] The ionomer resin composition of the present invention can be used to produce a resin sheet that is excellent in transparency, glass adhesion, coloration resistance, and thermal decomposition resistance, as well as sufficient creep resistance. Therefore, this resin sheet can be suitably used as an interlayer film for laminated glass, for example, for architectural and structural applications (e.g., laminates for facades, exterior walls, or roofs, panels, doors, windows, walls, roofs, sunroofs, soundproof walls, display windows, balconies, handrail walls, and other building materials; conference room partition glass components; solar panels, etc.), or for vehicular applications (e.g., automobile windshields, automobile side glass, automobile sunroofs, automobile rear glass, head-up display glass, etc.). Furthermore, the laminated glass of the present invention can be suitably used as laminated glass for architectural and structural applications or vehicular applications.

Claims

1. An ionomer resin containing (meth)acrylic acid units (A), (meth)acrylic acid neutralized units (B), and ethylene units (C), and an organic compound, wherein the total content of the units (A) and the units (B) is 6 to 10 mol% based on all monomer units constituting the ionomer resin, the organic compound is at least one organic compound selected from the group consisting of aromatic compounds, alcohols, organic carboxylic acids, and organic carboxylic acid esters, which is liquid at 23°C, the content of the organic compound is 1 mass ppm or more and 300 mass ppm or less, a resin composition.

2. The ionomer resin further contains (meth)acrylic acid ester units (D), and the total content of the units (A), the units (B), and the units (D) is 6 to 10 mol% based on all monomer units constituting the ionomer resin. The resin composition according to Claim 1.

3. The organic compound is at least one organic compound selected from the group consisting of toluene, xylene, ethanol, 1-butanol, methacrylic acid, acrylic acid, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, methyl acrylate, ethyl acrylate, and n-butyl acrylate. The resin composition according to Claim 1.

4. A resin sheet having one or more layers containing the resin composition according to any one of Claims 1 to 3.

5. A laminated glass interlayer comprising the resin sheet according to Claim 4.

6. A laminated glass having two glass plates and the laminated glass interlayer according to Claim 5 disposed between the two glass plates.