Ionomer resin composition, resin sheet, and laminated glass

Abstract

The present invention relates to an ionomer resin composition comprising an ionomer resin and a silane coupling agent, wherein: the ionomer resin includes a (meth)acrylic acid unit (A), a (meth)acrylic acid neutralized unit (B), and an ethylene unit (C); the total content of the unit (A) and the unit (B) is 6-10 mol% with respect to the total monomer units constituting the ionomer resin; the content of a salt formed by a strong acid and a strong base in the ionomer resin composition is 1-400 mg / kg; and the content of the silane coupling agent is 0.005-0.5 parts by mass with respect to 100 parts by mass of the ionomer resin.

Description

Ionomer resin composition, resin sheet and laminated glass

[0001] This patent application claims priority under the Paris Convention to Japanese Patent Application No. 2021-104273 (filing date: June 23, 2021), the entire contents of which are incorporated herein by reference. The present invention relates to an ionomer resin composition, a resin sheet comprising one or more layers containing the ionomer resin composition, a laminated glass interlayer film comprising the resin sheet, and laminated glass having the laminated glass interlayer film.

[0002] Ionomers, which are neutralized ethylene-unsaturated carboxylic acid copolymers, are used as interlayer films in laminated glass because of their excellent transparency and adhesion to glass (see, for example, Patent Document 1). In recent years, performance requirements for laminated glass have increased, and ionomer resins are also required to maintain high transparency regardless of the manufacturing conditions of the laminated glass, maintain a high elastic modulus even at high temperatures so as not to reduce the strength of the laminated glass, be less colored and have an excellent appearance, and be more adhesive to glass and less likely to peel from the glass.

[0003] 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.

[0004] Patent Document 3 describes a resin composition containing a homogeneous mixture of an ionomer resin and a dialkoxysilane compound as an adhesion promoter.

[0005] US Patent No. 6,432,522 Specification JP 2017-519083 A JP 2020-529500 A

[0006] Patent Document 2 describes that the ionomer described therein exhibits improved optical properties (haze) compared to conventional ionomers. However, according to studies by the present inventors, it has been found that the ionomer described in Patent Document 2 is prone to thermal decomposition during molding processing, and the resulting interlayer film is prone to have defects such as black foreign matter.

[0007] Furthermore, when laminated glass is used outdoors, moisture from rain or the like can cause peeling between the glass and the laminated glass interlayer, particularly at the edges of the laminated glass, or whitening and a decrease in transparency. Therefore, there is a demand for ionomer resins that can form laminated glass interlayers that are highly transparent and adhere to glass even in wet conditions.

[0008] Patent Document 3 describes that the resin composition described therein has improved adhesion to glass in a wet state. However, according to studies by the present inventors, it has been found that the resin composition described in Patent Document 3 is susceptible to thermal decomposition during molding, and the resulting interlayer film may have drawbacks such as black impurities. In addition, a crosslinked gel may be formed by a crosslinking reaction with a dialkoxysilane compound during molding, and further improvements are needed to obtain an interlayer film with good appearance.

[0009] Therefore, an object of the present invention is to provide an ionomer resin composition that is excellent in transparency, resistance to thermal decomposition, and adhesion to substrates such as glass in a wet state.

[0010] The present inventors have conducted extensive research to solve the above problems and have arrived at the present invention, which provides the following preferred embodiments.

[0011] [1] An ionomer resin composition comprising an ionomer resin and a silane coupling agent, wherein the ionomer resin comprises (meth)acrylic acid units (A), (meth)acrylic acid neutralized units (B), and ethylene units (C), the total content of the units (A) and the units (B) being 6 to 10 mol % based on all monomer units constituting the ionomer resin, the content of a salt of a strong acid and a strong base in the ionomer resin being 1 to 400 mg / kg, and the content of the silane coupling agent being 0.005 to 0.5 parts by mass per 100 parts by mass of the ionomer resin. [2] The ionomer resin composition according to [1], wherein the ionomer resin further comprises (meth)acrylic acid ester units (D), the total content of the units (A), the units (B), and the units (D) being 6 to 10 mol % based on all monomer units constituting the ionomer resin. [3] The ionomer resin composition according to [1] or [2], wherein the salt of a strong acid and a strong base is a metal salt of an alkali metal and / or an alkaline earth metal. [4] The ionomer resin composition according to any one of [1] to [3], wherein the salt of a strong acid and a strong base is a salt consisting of at least one cation selected from the group consisting of sodium ions and potassium ions and at least one anion selected from the group consisting of halogen ions, nitrate ions, and sulfate ions. [5] The ionomer resin composition according to any one of [1] to [4], wherein the silane coupling agent is at least one silane coupling agent selected from the group consisting of amino compounds, glycidoxy compounds, sulfide compounds, mercapto compounds, vinyl compounds, nitro compounds, and chloro compounds. [6] The ionomer resin composition according to any one of [1] to [5], wherein the silane coupling agent is at least one silane coupling agent selected from the group consisting of N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane and 3-glycidoxypropylmethyldiethoxysilane. [7] A resin sheet comprising one or more layers containing the ionomer resin composition according to any one of [1] to [6].[8] A laminated glass interlayer film comprising the resin sheet according to [7]. [9] A laminated glass having two glass plates and the laminated glass interlayer film according to [8] disposed between the two glass plates.

[0012] According to the present invention, it is possible to provide an ionomer resin composition that is excellent in transparency, resistance to thermal decomposition, and adhesion to substrates such as glass in a wet state.

[0013] [Ionomer Resin Composition] The ionomer resin composition of the present invention comprises an ionomer resin containing 1 to 400 mg / kg of a salt of a strong acid and a strong base, and 0.005 to 0.5 parts by mass of a silane coupling agent relative to 100 parts by mass of the ionomer resin, wherein the ionomer resin contains (meth)acrylic acid units (A), (meth)acrylic acid neutralized units (B), and ethylene units (C), and the total content of the units (A) and the units (B) is 6 to 10 mol % based on all monomer units constituting the ionomer resin. The present inventors have conducted further studies on ionomer resin compositions and have surprisingly found that by combining an ionomer resin that contains a specific amount of a specific unit and also contains 1 to 400 mg / kg of a salt of a strong acid and a strong base with 0.005 to 0.5 parts by mass of a silane coupling agent per 100 parts by mass of the ionomer resin, an ionomer resin composition that is excellent in transparency, resistance to thermal decomposition, and adhesion to substrates such as glass in a wet state can be obtained.

[0014] In this specification, the term "unit" means a "structural unit derived from," and for example, a (meth)acrylic acid unit refers to a structural unit derived from (meth)acrylic acid, a (meth)acrylic acid neutralization product unit refers to a structural unit derived from a (meth)acrylic acid neutralization product, and an ethylene unit refers to a structural unit derived from ethylene. Furthermore, in this specification, "(meth)acrylic acid" refers to methacrylic acid or acrylic acid.

[0015] [Ionomer Resin] 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 the units (B) is 6 to 10 mol % based on all monomer units constituting the ionomer resin. By having the total content within the above range, transparency and adhesion to substrates such as glass can be improved.

[0016] 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 the ionomer resin composition is slowly cooled 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 substrates such as glass of the ionomer resin composition. Furthermore, from the viewpoint of easily improving molding processability, it is 10 mol% or less, preferably 9.9 mol% or less, and more preferably 9.5 mol% or less.

[0017] The total content of the units (A) and the units (B) can be adjusted by the method for producing the ionomer resin. More specifically, when an ionomer resin is produced using an ethylene-(meth)acrylic acid ester copolymer as a raw material by a method including a step of saponifying the copolymer, the total content can be adjusted by the reactivity (conversion rate) of each reaction for converting 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 product units (B) by the saponification reaction and the demetallation reaction.

[0018] <(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 substrates, methacrylic acid is preferred. These (meth)acrylic acid units may be used alone or in combination of two types.

[0019] 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 above-mentioned lower limit, the transparency of the ionomer resin composition and its adhesion to substrates are likely to be improved. When the content is equal to or less than the above-mentioned upper limit, the moldability is likely to be improved.

[0020] <(Meth)acrylic acid neutralized unit (B)> The (meth)acrylic acid neutralized unit (B) is preferably a neutralized unit of the (meth)acrylic acid unit (A). The (meth)acrylic acid neutralized unit 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.

[0021] 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 1.3 mol % or more, still 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 above-mentioned lower limit, transparency and elastic modulus are easily improved, and when it is equal to or less than the above-mentioned upper limit, an increase in melt viscosity during molding processing is easily suppressed.

[0022] When an ionomer resin is produced using an ethylene-(meth)acrylic acid ester copolymer as a raw material by a method including a saponification reaction step and a demetallation reaction step of the copolymer, the contents of the units (A) and the units (B) can be adjusted by the reactivity in each reaction for converting 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) by the saponification reaction and the demetallation reaction.

[0023] <Ethylene Units (C)> The content of the ethylene units (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 impact resistance of the ionomer resin composition, and is preferably 94 mol% or less, more preferably 91 mol% or less, from the viewpoint of easily increasing the transparency of the ionomer resin composition (particularly the transparency during slow cooling). When the content of the ethylene units (C) is at least the above lower limit, the mechanical strength and moldability are easily improved, and when it is at most the above upper limit, the transparency is easily improved.

[0024] <(Meth)acrylic acid ester units (D)> In one embodiment of the present invention, the ionomer resin preferably further contains (meth)acrylic acid ester units (D) in addition to the (meth)acrylic acid units (A), (meth)acrylic acid neutralization product units (B), and ethylene units (C), from the viewpoint of easily obtaining higher transparency.

[0025] 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 improving transparency (particularly transparency during 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 preferably 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 the molding processability of the ionomer resin composition. Furthermore, if the total content is equal to or greater than the lower limit, the transparency of the ionomer resin composition, particularly the transparency during slow cooling, is easily improved. 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 easily improving transparency (particularly transparency during slow cooling) and adhesion to substrates. Furthermore, from the viewpoint of molding processability, it is 10 mol% or less, preferably 9.9 mol% or less, and more preferably 9.5 mol% or less.

[0026] 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 produced using an ethylene-(meth)acrylic acid ester copolymer as a raw material by a method including a saponification 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. Patent 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.

[0027] 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. Of 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, even more preferred monomers are methyl (meth)acrylate, n-butyl (meth)acrylate, and isobutyl (meth)acrylate, and particularly preferred monomer is methyl (meth)acrylate. These (meth)acrylic acid esters may be used alone or in combination of two or more.

[0028] 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 lower limit and at most the above upper limit, the transparency of the ionomer resin composition is likely to be improved.

[0029] 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 of converting the (meth)acrylic acid ester units (D) in the ethylene-(meth)acrylic acid ester copolymer into (meth)acrylic acid units (A) when the ionomer resin is produced 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.

[0030] <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 (A1) other than the (meth)acrylic acid units (A) and carboxylic acid neutralized units (B1) other than the (meth)acrylic acid neutralized units (B). Examples of monomers constituting the carboxylic acid units (A1) 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 (B1) include neutralized units of the carboxylic acid units (A1). 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 of one type alone or a combination of two or more types. These other monomer units may be of one type alone or a combination of two or more types.

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

[0032] 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) when contained, and other monomer units (e.g., units (A1) and units (B1)) in the ionomer resin can be determined by first identifying the monomer units in the ionomer resin 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 method combining 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.

[0033] <Salt of Strong Acid and Strong Base> The ionomer resin contains 1 to 400 mg / kg of a salt of a strong acid and a strong base (hereinafter simply referred to as "salt"). The present inventors have found that when the ionomer resin contains 1 to 400 mg / kg of salt, the ionomer resin composition can maintain high transparency (particularly transparency upon water absorption) while improving thermal decomposition resistance. Therefore, the ionomer resin composition of the present invention can achieve both high transparency and high thermal decomposition resistance. Although the reason why the ionomer resin composition of the present invention has excellent thermal decomposition resistance when containing a salt within the above range is not clear, it is thought that this is because the interaction between the salt and the (meth)acrylic acid units (A) in the ionomer resin can suppress thermal elimination of the (meth)acrylic acid units (A) in the ionomer resin.

[0034] Furthermore, the present inventors have also found that, although the combination of an ionomer resin with a silane coupling agent typically tends to produce black foreign matter or crosslinked gel during molding, making it difficult to obtain a resin sheet with good appearance, when the ionomer resin contains 1 to 400 mg / kg of salt, it is surprisingly easy to obtain a resin sheet with good appearance. Although the reason for this is not clear, it is thought that the inclusion of a salt improves the thermal decomposition resistance of the ionomer resin composition.

[0035] If the salt content exceeds the upper limit, the transparency of the ionomer resin composition tends to decrease. If the salt content is below the lower limit, the thermal decomposition resistance decreases, making the ionomer resin composition more susceptible to thermal decomposition, for example, during molding. The salt content is 1 mg / kg or more, preferably 3 mg / kg or more, and more preferably 5 mg / kg or more, from the viewpoint of easily improving thermal decomposition resistance and the appearance of the resulting resin sheet. Furthermore, from the viewpoint of easily improving transparency (particularly transparency upon water absorption) and the appearance of the resulting resin sheet, the salt content is 400 mg / kg or less, preferably 380 mg / kg or less, more preferably 350 mg / kg or less, even more preferably 320 mg / kg or less, even more preferably 300 mg / kg or less, and particularly preferably 200 mg / kg or less. The salt content in the ionomer resin can be appropriately selected depending on the method for incorporating the salt into the ionomer resin, as described below. The salt content in the ionomer resin can be measured using ion chromatography, for example, by the method described in the Examples.

[0036] The salts of strong acids and strong bases are not particularly limited, and examples thereof include alkali metal and / or alkaline earth metal salts of strong acids and strong bases. These salts may be used alone or in combination of two or more. Examples of alkali metal salts include lithium salts, sodium salts, potassium salts, rubidium salts, and cesium salts. From the viewpoint of easily improving the thermal decomposition resistance of the ionomer resin composition and easily obtaining a resin sheet with good appearance, preferred alkali metal salts are lithium salts, sodium salts, and potassium salts, more preferably sodium salts and potassium salts, and even more preferably sodium salts. Examples of alkaline earth metal salts include beryllium salts, magnesium salts, calcium salts, strontium salts, and barium salts. From the viewpoint of easily improving the thermal decomposition resistance of the ionomer resin composition, preferred alkaline earth metal salts are magnesium salts and calcium salts.

[0037] From the viewpoint of easily increasing the thermal decomposition resistance of the ionomer resin composition and easily obtaining a resin sheet with good appearance, a more preferred salt is a salt consisting of at least one cation selected from the group consisting of sodium ions, potassium ions, magnesium ions, and calcium ions, and at least one anion selected from the group consisting of halogen ions, sulfate ions, nitrate ions, and sulfonate ions, and even more preferred is a salt consisting of at least one cation selected from the group consisting of sodium ions and potassium ions, and at least one anion selected from the group consisting of halogen ions, sulfate ions, and nitrate ions.

[0038] Specific examples of preferred salts include sodium chloride, potassium chloride, magnesium chloride, calcium chloride, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate, sodium nitrate, potassium nitrate, magnesium nitrate, calcium nitrate, sodium p-toluenesulfonate, potassium p-toluenesulfonate, magnesium p-toluenesulfonate, and calcium p-toluenesulfonate. From the viewpoint of easily improving transparency and thermal decomposition resistance and easily obtaining a resin sheet with good appearance, more preferred salts are sodium chloride, potassium chloride, sodium sulfate, potassium sulfate, sodium nitrate, and potassium nitrate, and even more preferred are sodium chloride, sodium sulfate, and sodium nitrate.

[0039] The method for incorporating a salt into an ionomer resin is not particularly limited, and examples thereof include (I) a method in which a salt is generated and incorporated into the ionomer resin during the production process, (II) a method in which a salt is added separately during the production process of the ionomer resin, and (III) a method in which a salt-free ionomer resin is produced and a salt is subsequently added to the resin, etc. Of these methods, method (I), in which a salt is generated and incorporated into the ionomer resin during the production process, is preferred from the viewpoint that the salt can be easily dispersed uniformly in the ionomer resin, thereby facilitating improvements in transparency and thermal decomposition resistance.

[0040] The method for adjusting the content of salts of strong acids and strong bases in the ionomer resin can be selected appropriately depending on the method for incorporating the salts. For example, when incorporating salts by the method (I), the content can be adjusted by controlling the cleanliness of the resulting resin. More specifically, the content of salts in the ionomer resin can be adjusted by controlling the number of washes in the step of washing the resulting resin with a cleaning solution. Examples of the cleaning solution include solvents that are good solvents for salts and poor solvents for resins, such as water, alcohols such as methanol, ketones such as acetone, and mixed solvents thereof. When incorporating salts by the methods (II) and (III), the content of salts in the ionomer resin can be adjusted by controlling the amount of salt added separately and the amount of salt added later, respectively.

[0041] The dispersion state of the salt of a strong acid and a strong base in the ionomer resin is not particularly limited, but it is preferably uniformly dispersed in the ionomer resin from the viewpoint of easily improving transparency and thermal decomposition resistance and easily obtaining a resin sheet with good appearance.

[0042] In one embodiment of the present invention, the degree of branching per 1,000 carbon atoms of the ionomer resin is not particularly limited and is preferably 5 to 30, 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 synthesized by the EMMA saponification method, by the polymerization temperature during synthesis of the ethylene-(meth)acrylic acid ester (X). The degree of branching per 1,000 carbon atoms can be measured by the DDMAS method using solid-state NMR.

[0043] 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 viewpoint of heat resistance and thermal decomposition resistance, and is preferably 200°C or lower, more preferably 180°C or lower, and even more preferably 150°C or lower from the viewpoint of easily exhibiting adhesive strength with glass when preparing laminated glass. 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 in the second heating cycle.

[0044] 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.

[0045] In one embodiment of the present invention, the melt flow rate (MFR) of the ionomer resin measured in accordance with JIS K7210-1:2014 under conditions of 190°C and 2.16 kg is preferably 0.1 g / 10 min or more, more preferably 0.3 g / 10 min or more, even more preferably 0.7 g / 10 min or more, still more preferably 1.0 g / 10 min or more, particularly preferably 1.5 g / 10 min or more, and preferably 50 g / 10 min or less, more preferably 30 g / 10 min or less, and particularly preferably 10 g / 10 min or less. When the MFR is at least the above-mentioned lower limit and at most the above-mentioned upper limit, molding processing is facilitated with reduced deterioration due to heat, and a resin sheet with excellent penetration resistance is easily obtained.

[0046] 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.

[0047] <Method for Producing Ionomer Resin> The method for producing the ionomer resin of the present invention is not particularly limited. For example, as described above in connection with the method for incorporating a salt into the ionomer resin, the ionomer resin may be produced by (I) generating a salt during the ionomer resin production process, (II) separately adding a salt during the ionomer resin production process, or (III) first producing a salt-free ionomer resin and then adding a salt to the resin. Among these methods, method (I), in which a salt is generated and incorporated into the ionomer resin during the ionomer resin production process, is preferred from the viewpoint of easily dispersing a salt of a strong acid and a strong base uniformly in the ionomer resin, thereby improving the transparency and thermal decomposition resistance of the ionomer resin composition. Method (I) is described in detail below.

[0048] Examples of the method (I) include a method in which an ethylene-(meth)acrylic acid ester copolymer (X) is used as a raw material, and all or a part of the (meth)acrylic acid ester units in the copolymer are converted into (meth)acrylic acid units and (meth)acrylic acid neutralizer units to produce a crude ionomer resin containing (meth)acrylic acid units (A), (meth)acrylic acid neutralizer units (B), ethylene units (C) and, in some cases, (meth)acrylic acid ester units (D) (step i), a poor solvent is added to a solution of the obtained crude ionomer resin to precipitate a granular resin (step ii), and the precipitated granular resin is then washed with a washing liquid (step iii).

[0049] (Step i) Examples of a method for converting all or a portion of the (meth)acrylic acid ester units in the ethylene-(meth)acrylic acid ester copolymer (X) into (meth)acrylic acid units and (meth)acrylic acid neutralizer units include a method (hereinafter also referred to as method (1)) in which the ethylene-(meth)acrylic acid ester copolymer (X) is saponified with a strong base to convert all or a portion of the (meth)acrylic acid ester units into (meth)acrylic acid neutralizer units, thereby obtaining an ethylene-(meth)acrylic acid neutralizer copolymer or an ethylene-(meth)acrylic acid ester-(meth)acrylic acid neutralizer copolymer, and then some of the (meth)acrylic acid neutralizer units in the obtained copolymer are demetallized with a strong acid to convert them into (meth)acrylic acid units. An example of a method other than the method (1) is a method in which all of the (meth)acrylic acid neutralization units in an ethylene-(meth)acrylic acid neutralization copolymer or an ethylene-(meth)acrylic acid ester-(meth)acrylic acid neutralization copolymer obtained by the saponification in the method (1) are demetallized with a strong acid to convert them into (meth)acrylic acid units, thereby obtaining an ethylene-(meth)acrylic acid copolymer or an ethylene-(meth)acrylic acid ester-(meth)acrylic acid copolymer, and then neutralizing some of the (meth)acrylic acid units in the obtained copolymer with a metal ion (hereinafter also referred to as method (2)). Note that in the methods (1) and (2), a salt of the strong acid and the strong base is produced by the neutralization reaction between the strong base used in the saponification reaction and the strong acid used in the demetallization, and a crude ionomer resin containing the salt of the strong acid and the strong base is obtained.

[0050] 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 is methyl (meth)acrylate. These (meth)acrylic acid esters may be used alone or in combination of two or more.

[0051] 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, ethylene-sec-butyl methacrylate copolymer, etc. As these copolymers, 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 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.

[0052] 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, and 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), (meth)acrylic acid neutralized units (B), and (meth)acrylic acid ester units (D), if contained, in the resulting crude ionomer resin and ionomer resin. Therefore, when the content of (meth)acrylic acid ester units in the copolymer (X) is at least the above-mentioned lower limit, the transparency of the resulting ionomer resin composition, particularly the transparency during slow cooling, is likely to be improved. On the other hand, when the content is at most the above-mentioned upper limit, the moldability of the resulting ionomer resin composition is likely to be improved. 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 (A1) and the unit (B1)) in the ionomer resin.

[0053] 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 moldability and strength of the resulting ionomer resin composition are likely to be improved. The MFR of the ethylene-(meth)acrylic acid ester copolymer (X) can be adjusted by the degree of polymerization and the content of (meth)acrylic acid ester units. The MFR can be measured, for example, by the method described in the Examples.

[0054] 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.

[0055] 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 dissolving the ethylene-(meth)acrylic acid ester copolymer (X) in deuterated orthodichlorobenzene, １３ It can be measured by the inverse gate decoupling method of C-NMR.

[0056] Examples of the alkali used in the saponification reaction in the above methods (1) and (2) include strong bases such as sodium hydroxide, potassium hydroxide, and calcium hydroxide, and from the viewpoints of solubility in the solvent used in the saponification reaction and economy, sodium hydroxide and potassium hydroxide are preferred.

[0057] Examples of solvents used in the saponification reaction include ethers such as tetrahydrofuran and dioxane; halogen-containing solvents such as chloroform and dichlorobenzene; ketones having 6 or more carbon atoms such as methyl butyl ketone; mixed solvents of hydrocarbon compounds and alcohols such as methanol, ethanol, 1-propanol, 2-propanol, and 1-butanol; aromatic compounds such as benzene, toluene, xylene, and ethylbenzene; and mixed solvents of aromatic compounds and alcohols. These solvents may be used alone or in combination of two or more. Among these, from the viewpoint of the solubility of the resin before and after the saponification reaction, preferred solvents are 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 appropriately selected depending on the type of each solvent used. 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.

[0058] 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 not particularly limited as long as it is lower than the temperature at which the ethylene-(meth)acrylic acid ester copolymer (X) decomposes, and is, for example, 300° C. or lower.

[0059] 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.

[0060] Examples of acids used for demetallization in the above methods (1) and (2) include strong acids such as hydrochloric acid, nitric acid, sulfuric acid, and toluenesulfonic acid. These acids may be used alone or in combination of two or more. From the viewpoint of facilitating removal of salts from the ionomer resin after demetallization, inorganic acids such as hydrochloric acid, nitric acid, and sulfuric acid are preferred. The solvent used for the demetallization can be the same as the solvent used for the saponification reaction described above.

[0061] The temperature at which the demetallization is carried out is preferably 20°C or higher, more preferably 30°C or higher, and even more preferably 40°C or higher, from the viewpoint of easily reducing the viscosity of the reaction solution, and is preferably 100°C or lower, more preferably 80°C or lower, and even more preferably 60°C or lower.

[0062] The demetallation may be carried out in air or in an inert gas such as nitrogen gas or argon gas, similarly to the saponification reaction, and may be carried out under normal pressure, elevated pressure, or reduced pressure, preferably elevated pressure.

[0063] In the above method (2), the neutralizing agent used when neutralizing a portion of the (meth)acrylic acid units to convert them into (meth)acrylic acid neutralized units is not particularly limited as long as it is an ionic compound containing a metal ion. Examples of the metal ion include alkali metal ions such as lithium, potassium, and sodium, alkaline earth metal ions such as magnesium and calcium, transition metal ions such as zinc, nickel, iron, and titanium, and aluminum ions. For example, when the metal ion is a sodium ion, an example of the neutralizing agent is sodium hydroxide.

[0064] (Step ii) (Crude Ionomer Resin Solution) The crude ionomer resin obtained in step i contains (meth)acrylic acid units (A), (meth)acrylic acid neutralized product 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 crude ionomer resin. Furthermore, the crude ionomer resin preferably contains (meth)acrylic acid ester units (D) in addition to the units (A), (B), and (C), and when the crude 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 crude ionomer resin. Furthermore, the crude ionomer resin may further contain other monomer units, such as carboxylic acid units (A1) other than (meth)acrylic acid units and carboxylic acid neutralization units (B1) other than (meth)acrylic acid neutralization units, in addition to the units (A), (B), and (C), and optionally the units (D).

[0065] Examples of the units (A) and (B) in the crude ionomer resin, as well as the unit (D) and other monomer units (A1) and (B1) that may be contained in the crude ionomer resin, include the same units as those described above as the units (A), (B), (D), (A1), and (B1) contained in the ionomer resin of the present invention, and preferred forms are also the same as those for the ionomer resin described above. Furthermore, the content of each unit in the crude ionomer resin, the total content of units (A) and (B), and the total content of units (A), (B), and (D) when unit (D) is optionally contained, are also the same as those for the ionomer resin of the present invention, including the contents and preferred forms, described above for the ionomer resin of the present invention.

[0066] The crude ionomer resin solution can be prepared by dissolving the crude ionomer resin obtained in step i in a solvent, and the reaction solution of the crude ionomer resin obtained in step i may be used as the crude ionomer resin solution.

[0067] The solvent for the crude ionomer resin solution is not particularly limited as long as it is a solvent capable of dissolving the crude ionomer resin, and examples thereof include the same solvents as those used in the saponification reaction. Among these, from the viewpoint of solubility of the crude ionomer resin, 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.

[0068] The concentration of the crude ionomer resin solution is preferably 30% by mass or less, more preferably 15% by mass or less, and also preferably 1% by mass or more, more preferably 5% by mass or more, from the viewpoints that a granular resin having a small particle size is easily obtained, as a result, it is easy to adjust the salt content in the ionomer resin to within a range of 1 to 400 mg / kg, and it is easy to improve the thermal decomposition resistance of the ionomer resin.

[0069] The temperature of the crude ionomer resin solution 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 viewpoints of easily suppressing aggregation or agglutination of the precipitated granular resin, easily adjusting the salt content in the ionomer resin to within a range of 1 to 400 mg / kg, and easily improving the thermal decomposition resistance of the ionomer resin composition. Furthermore, from the viewpoint of the fluidity of the crude ionomer resin solution, the temperature is more preferably equal to or higher than 25°C, and even more preferably equal to or higher than 30°C.

[0070] (Poor Solvent) The poor solvent to be added to the crude ionomer resin solution is not particularly limited as long as it is a solvent that will mix with the crude ionomer resin solution and will not dissolve the ionomer resin. Examples 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 facilitating drying of the ionomer resin due to their low boiling points and facilitating removal of salts from the granular resin due to their ability to dissolve salts, 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.

[0071] The amount of the poor solvent added may be appropriately selected depending on the concentration of the crude ionomer resin solution. For example, the amount of the 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 solution. There is no particular upper limit to the amount of the poor solvent added, and it is usually 1,000 parts by mass or less per 100 parts by mass of the crude ionomer resin solution.

[0072] The method for adding the poor solvent to the crude ionomer resin solution is not particularly limited. For example, the poor solvent may be added to the crude ionomer resin solution all at once, or may be added in multiple portions by dropwise addition, etc. From the viewpoint that the particle size of the granular resin is likely to be small, which makes it easier to improve the removal of salts in the granular resin and, as a result, makes it easier to improve the transparency of the 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.

[0073] After adding the poor solvent to the crude ionomer resin solution, it is preferable to stir the mixture of the crude ionomer resin solution and the poor solvent. The stirring speed is not particularly limited, but the faster the stirring speed, the easier it is to obtain a granular resin with a small particle size. The stirring time is not particularly limited, and may be, for example, stirred until the granular resin precipitates and the mixture of the crude ionomer resin 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.

[0074] (Granular Resin) The peak-top particle size of the granular resin precipitated by adding a poor solvent to a solution of a crude ionomer resin 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 reducing the salt content in the granular resin by increasing the specific surface area of ​​the granular resin, thereby making it easier to adjust the salt content to within a range of 1 to 400 mg / kg and easily improving the thermal decomposition resistance of the ionomer resin composition. Furthermore, from the viewpoint of easily improving the filterability of the granular resin and easily improving the production efficiency of the ionomer resin, 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 determined, for example, by measuring the particle size distribution of the granular resin using a laser diffraction / scattering particle size distribution analyzer.

[0075] The peak-top particle size of the granular resin precipitated by adding a poor solvent to a crude ionomer resin solution can be adjusted by the concentration and temperature of the crude ionomer resin solution. Specifically, lowering the concentration and / or temperature of the crude ionomer resin solution reduces the peak-top particle size of the precipitated granular resin, while increasing the concentration and / or temperature of the crude ionomer resin solution increases the peak-top particle size of the precipitated granular resin. The peak-top particle size of the granular resin can also be adjusted by the method of adding the poor solvent and the stirring speed of the mixture of the crude ionomer resin solution and the poor solvent.

[0076] (Step iii) (Washing Liquid) The washing liquid in step iii is not particularly limited as long as it is a solvent in which the ionomer resin does not dissolve and which can dissolve the salt. Examples of preferred 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.

[0077] Among these cleaning solutions, alcohols, water, and mixtures thereof are preferred from the viewpoint of high salt solubility and easy removal of salt contained in the granular resin. Furthermore, a more preferred cleaning solution is a mixture of water and alcohols from the viewpoints of increasing salt solubility and, by making the specific gravity of the cleaning solution smaller than that of the granular resin, increasing the contact area between the cleaning solution and the granular resin, thereby easily improving salt removal, facilitating removal of impurities such as organic compounds contained in the granular resin, and facilitating drying of the ionomer resin obtained after washing. Preferred alcohols are methanol and ethanol, more preferably methanol, because they dry easily 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.

[0078] An example of a method for washing the granular resin with a washing liquid is a method in which the granular resin is filtered out from the granular resin dispersion in which the granular resin precipitated in step ii, the filtered granular resin is mixed with the washing liquid, and the liquid is then removed. More specifically, a washing method is exemplified in which the granular resin filtered out from the granular resin dispersion is mixed with the washing liquid, the granular resin is filtered out from the washing liquid (hereinafter also referred to as washing step (a)), the filtered granular resin is then mixed with new washing liquid, and the granular resin is filtered out from the washing liquid (hereinafter also referred to as washing step (b)). From the viewpoints of easily adjusting the salt content in the granular resin to within a range of 1 to 400 mg / kg, easily improving the thermal decomposition resistance of the ionomer resin composition, and improving the production efficiency of the ionomer resin, in the case of a batch process, the granular resin is preferably washed, for example, by performing one washing step (a) followed by one to ten washing steps (b), and the number of times that the washing step (b) is performed after one washing step (a) is more preferably one to six, and even more preferably one to four times.

[0079] The amount of the cleaning solution used per washing step may be appropriately selected depending on the amount of granular resin 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 resin on a dry basis.

[0080] The ionomer resin obtained in step iii may be dried, if necessary, at a drying temperature preferably equal to or lower than the melting point of the ionomer resin, more preferably equal to or lower than 80°C.

[0081] [Silane Coupling Agent] The ionomer resin composition of the present invention contains 0.005 to 0.5 parts by mass of a silane coupling agent per 100 parts by mass of the ionomer resin. By including a silane coupling agent within the above range, adhesion to glass, particularly adhesion to glass in a wet state, can be improved. This is believed to be because the silane coupling agent has a reactive group that reacts with inorganic materials such as glass and a reactive group that reacts with organic materials such as resin, allowing the silane coupling agent to bond the ionomer resin to glass via a chemical bond or an ionic bond. Furthermore, in the present invention, even a small amount of silane coupling agent, such as 0.005 to 0.5 parts by mass per 100 parts by mass of the ionomer resin, can enhance adhesion between the ionomer resin composition and glass. Therefore, even when the silane coupling agent is included, the formation of a crosslinked gel is suppressed, resulting in a resin sheet with excellent appearance, such as excellent surface smoothness. On the other hand, if the content of the silane coupling agent is less than the above lower limit, adhesion to glass in a wet state tends to decrease, making peeling from the glass more likely to occur in a wet state. Furthermore, if the content exceeds the upper limit, gelation tends to proceed due to the crosslinking reaction caused by the silane coupling agent, making it difficult to obtain a resin sheet with a good appearance.

[0082] In one embodiment of the present invention, the content of the silane coupling agent is 0.005 parts by mass or more, preferably 0.01 parts by mass or more, more preferably 0.02 parts by mass or more, even more preferably 0.05 parts by mass or more, still more preferably 0.07 parts by mass or more, and particularly preferably 0.08 parts by mass or more, per 100 parts by mass of the ionomer resin, from the viewpoint of easily improving adhesion to glass, particularly adhesion to glass in a wet state. Furthermore, the content is 0.5 parts by mass or less, preferably 0.4 parts by mass or less, more preferably 0.3 parts by mass or less, even more preferably 0.2 parts by mass or less, and particularly preferably 0.18 parts by mass or less, per 100 parts by mass of the ionomer resin, from the viewpoint of easily suppressing gelation of the ionomer resin composition and easily obtaining a resin sheet with good appearance.

[0083] The silane coupling agent is not particularly limited, and examples thereof include amino compounds, glycidoxy compounds, sulfide compounds, mercapto compounds, vinyl compounds, nitro compounds, chloro compounds, etc. These silane coupling agents may be used alone or in combination of two or more.

[0084] Examples of amino compounds include N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminomethyl)-3-aminopropyltrimethoxysilane, N-(2-aminomethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminomethyl)-3-aminopropylmethyldiethoxysilane, N-(2-aminomethyl)-3-aminopropyltriethoxysilane, and 3-aminopropyltrimethoxysilane. Examples of the silane include silane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride, N-(2-aminomethyl)-8-aminooctyltrimethoxysilane, N-(2-aminoethyl)-8-aminooctyltrimethoxysilane, N-(2-aminomethyl)-8-aminooctyltriethoxysilane, and N-(2-aminoethyl)-8-aminooctyltriethoxysilane.

[0085] Examples of the glycidoxy compounds include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane.

[0086] Examples of sulfide compounds include bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(3-triethoxysilylpropyl)trisulfide, bis(3-trimethoxysilylpropyl)trisulfide, bis(3-triethoxysilylpropyl)disulfide, bis(3-trimethoxysilylpropyl)disulfide, and 3-trimethoxysilylpropyl-N,N-dimethylsilyl. thiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 2-trimethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropyl benzothiazole tetrasulfide, 3-triethoxysilylpropyl benzothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, 3-octanoylthio-1-propyltriethoxysilane, and the like.

[0087] Examples of mercapto compounds include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, and 2-mercaptoethyltriethoxysilane.

[0088] Examples of vinyl compounds include vinyltriethoxysilane, vinyltrimethoxysilane, dimethoxymethylvinylsilane, and diethoxy(methyl)vinylsilane.

[0089] Examples of nitro compounds include 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane.

[0090] Examples of chloro-based compounds include 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, and 2-chloroethyltriethoxysilane.

[0091] Examples of other compounds include diethoxydimethylsilane, 1,3-diethoxy-1,1,3,3-tetramethyldisiloxane, dimethoxydimethylsilane, methyldiethoxysilane, diisopropyldimethoxysilane, dicyclopentyldimethoxysilane, octyltriethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, hexadecyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and N,N,N-tris(3-trimethoxysilylpropyl)triisocyanurate.

[0092] In one embodiment of the present invention, the silane coupling agent may be either a trialkoxysilane or a dialkoxysilane, but is preferably a dialkoxysilane from the viewpoint of easily improving adhesion to glass in a wet state.

[0093] In one embodiment of the present invention, from the viewpoint of easily improving adhesion to glass in a wet state, the silane coupling agent is preferably an amino compound or a glycidoxy compound, more preferably N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldiethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and even more preferably N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane or 3-glycidoxypropylmethyldiethoxysilane. These silane coupling agents can be used alone or in combination of two or more.

[0094] [Other Additives] In one embodiment of the present invention, the resin composition of the present invention may contain, in addition to the silane coupling agent, other additives as necessary. Examples of additives 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 and 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. The additives may be used alone or in combination of two or more.

[0095] An ultraviolet absorber is a compound capable of absorbing ultraviolet rays, and is said to have the function of converting light energy into heat energy. Examples of ultraviolet absorbers include benzophenones, benzotriazoles, triazines, benzoates, salicylates, cyanoacrylates, oxalic acid anilides, malonic acid esters, and formamidines. These may be used alone or in combination of two or more.

[0096] Benzotriazoles are preferred as ultraviolet absorbers because they are highly effective in suppressing deterioration of optical properties, such as coloration, due to exposure to ultraviolet light. Preferred examples of benzotriazoles include 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol (manufactured by BASF; trade name: TINUVIN 329), 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (manufactured by BASF; trade name: TINUVIN 234), 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-t-octylphenol] (manufactured by ADEKA Corporation; trade name: Adekastab LA-31), and 2-(5-octylthio-2H-benzotriazol-2-yl)-6-tert-butyl-4-methylphenol. These may be used alone or in combination of two or more.

[0097] Examples of triazine ultraviolet absorbers include 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methylphenyl)-1,3,5-triazine (manufactured by ADEKA Corporation; trade name: Adekastab LA-F70), its analogues, hydroxyphenyltriazine ultraviolet absorbers (manufactured by BASF; trade names: TINUVIN 477 and TINUVIN 460), and 2,4-diphenyl-6-(2-hydroxy-4-hexyloxyphenyl)-1,3,5-triazine. These may be used alone or in combination of two or more.

[0098] Examples of the antioxidant include known materials. Specific examples of the antioxidant include phenolic compounds such as hydroquinone, hydroquinone monomethyl ether, 2,5-di-t-butylphenol, 2,6-di(t-butyl)-4-methylphenol, and mono(or di- or tri)(α-methylbenzyl)phenol; bisphenol compounds such as 2,2′-methylenebis(4-ethyl-6-t-butylphenol), 4,4′-butylidenebis(3-methyl-6-t-butylphenol), and 4,4′-thiobis(3-methyl-6-t-butylphenol); benzimidazole compounds such as 2-mercaptobenzimidazole and 2-mercaptomethylbenzimidazole; amine-ketone compounds such as 2,2,4-trimethyl-1,2-dihydroquinoline, reaction products of diphenylamine and acetone, and 2,2,4-trimethyl-1,2-dihydroquinoline polymers; aromatic secondary amine compounds such as N-phenyl-1-naphthylamine, alkylated diphenylamine, octylated diphenylamine, 4,4'-bis(α,α-dimethylbenzyl)diphenylamine, p-(p-toluenesulfonylamido)diphenylamine, and N,N'-diphenyl-p-phenylenediamine; and thiourea compounds such as 1,3-bis(dimethylaminopropyl)-2-thiourea and tributylthiourea. These may be used alone or in combination of two or more.

[0099] The antioxidant is effective in preventing oxidative degradation of the resin by itself in the presence of oxygen. Examples include phosphorus-based antioxidants, hindered phenol-based antioxidants, and thioether-based antioxidants. These antioxidants may be used alone or in combination of two or more. Among them, from the viewpoint of the effect of preventing degradation of optical properties due to coloring, phosphorus-based antioxidants and hindered phenol-based antioxidants are preferred, and a combination of a phosphorus-based antioxidant and a hindered phenol-based antioxidant is more preferred.

[0100] When a phosphorus-based antioxidant and a hindered phenol-based antioxidant are used in combination, the mass ratio of the phosphorus-based antioxidant to the hindered phenol-based antioxidant is preferably 1:5 to 2:1, and more preferably 1:2 to 1:1.

[0101] Preferred examples of the phosphorus-based antioxidant include 2,2-methylenebis(4,6-di-t-butylphenyl)octyl phosphite (manufactured by ADEKA Corporation; trade name: Adekastab HP-10), tris(2,4-di-t-butylphenyl)phosphite (manufactured by BASF; trade name: IRGAFOS168), and 3,9-bis(2,6-di-t-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane (manufactured by ADEKA Corporation; trade name: Adekastab PEP-36). These may be used alone or in combination of two or more.

[0102] Examples of preferred hindered phenol-based antioxidants include pentaerythrityl-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] (manufactured by BASF; trade name: IRGANOX 1010) and octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate (manufactured by BASF; trade name: IRGANOX 1076). These may be used alone or in combination of two or more.

[0103] The thermal degradation inhibitor can prevent thermal degradation of a resin by capturing polymer radicals that are generated when the resin is exposed to high heat in a substantially oxygen-free state. Preferred examples of the thermal degradation inhibitor include 2-t-butyl-6-(3'-t-butyl-5'-methyl-hydroxybenzyl)-4-methylphenyl acrylate (manufactured by Sumitomo Chemical Co., Ltd.; trade name: Sumilizer GM) and 2,4-di-t-amyl-6-(3',5'-di-t-amyl-2'-hydroxy-α-methylbenzyl)phenyl acrylate (manufactured by Sumitomo Chemical Co., Ltd.; trade name: Sumilizer GS). These may be used alone or in combination of two or more.

[0104] Light stabilizers are compounds that are said to have the function of capturing radicals generated primarily by oxidation due to light. Preferred examples of light stabilizers include hindered amines such as compounds having a 2,2,6,6-tetraalkylpiperidine skeleton. These may be used alone or in combination of two or more.

[0105] Examples of the anti-sticking agent include salts or esters of fatty acids, esters of polyhydric alcohols, inorganic salts, inorganic oxides, and particulate resins. Preferred examples of the anti-sticking agent include calcium stearate, calcium carbonate, calcium sulfate, magnesium sulfate, barium sulfate, silicon dioxide (manufactured by Evonik; trade name: Aerosil), particulate acrylic resins, and the like. These may be used alone or in combination of two or more.

[0106] Examples of lubricants include stearic acid, behenic acid, stearamidic acid, methylene bisstearamide, hydroxystearic acid triglyceride, paraffin wax, ketone wax, octyl alcohol, hardened oil, etc. These may be used alone or in combination of two or more.

[0107] Examples of the release agent include higher alcohols such as cetyl alcohol and stearyl alcohol, and higher fatty acid esters of glycerin such as stearate monoglyceride and stearate diglyceride. These may be used alone or in combination of two or more.

[0108] Polymer processing aids are typically produced by emulsion polymerization and comprise polymer particles with a particle size of 0.05 to 0.5 μm. These polymer particles may be single-layer particles composed of a polymer with a single composition ratio and a single intrinsic viscosity, or multi-layer particles composed of two or more polymers with different composition ratios or intrinsic viscosities. These particles may be composed of one type alone or a combination of two or more types. Among these, preferred are particles with a two-layer structure, having an inner polymer layer with a low intrinsic viscosity and an outer polymer layer with a high intrinsic viscosity of 5 dl / g or more. The intrinsic viscosity of the polymer processing aid is preferably 3 to 6 dl / g. If the intrinsic viscosity is too low, the effect of improving moldability tends to be low, while if the intrinsic viscosity is too high, the moldability of the copolymer tends to be reduced.

[0109] As an example of the organic dye, a compound having a function of converting ultraviolet light into visible light is preferably used. The organic dye may be used alone or in combination of two or more kinds.

[0110] Examples of fluorescent substances include fluorescent pigments, fluorescent dyes, fluorescent white dyes, fluorescent brightening agents, fluorescent bleaches, etc. These may be used alone or in combination of two or more.

[0111] The content of the various additives can be appropriately selected within a range that does not impair the effects of the present invention, and the total content of the various additives is preferably 7 mass % or less, more preferably 5 mass % or less, and even more preferably 4 mass % or less, relative to the total mass of the resin composition.

[0112] [Ionomer Resin Composition] The ionomer resin composition of the present invention comprises an ionomer resin and a silane coupling agent, wherein the ionomer resin comprises (meth)acrylic acid units (A), (meth)acrylic acid neutralized units (B), and ethylene units (C), the total content of the units (A) and the units (B) being 6 to 10 mol% based on all monomer units constituting the ionomer resin, the content of a salt of a strong acid and a strong base in the ionomer resin being 1 to 400 mg / kg, and the content of the silane coupling agent being 0.005 to 0.5 parts by mass relative to 100 parts by mass of the ionomer resin, thereby enabling the formation of a resin sheet having high transparency, high resistance to thermal decomposition, and high adhesion to glass in a wet state, as well as excellent appearance.

[0113] In one embodiment of the present invention, from the viewpoint of easily improving transparency, thermal decomposition resistance, and adhesion to glass, particularly in a wet state, 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 still 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.

[0114] The ionomer resin composition of the present invention contains 1 to 400 mg / kg of salt as described above, thereby exhibiting high resistance to thermal decomposition. In a preferred embodiment of the present invention, the 1% weight loss temperature (Td1) of the ionomer resin composition of the present invention when heated at a rate of 10°C / min under a nitrogen atmosphere is preferably 330°C or higher, more preferably 350°C or higher, even more preferably 360°C or higher, and particularly preferably 370°C or higher, and typically 450°C or lower. When the 1% weight loss temperature of the ionomer resin composition is equal to or higher than the above-mentioned lower limit, foaming and / or thermal decomposition during melt molding of the ionomer resin composition is likely to be reduced, and an interlayer film free of defects such as bubbles and / or black impurities caused by thermal decomposition of the resin is likely to be obtained. Note that, in this specification, the 1% weight loss temperature refers to the temperature at which the weight loss rate becomes 1%, based on the weight at 200°C. The 1% weight loss temperature can be measured in accordance with JIS K7120:1987, for example, by the method described in the Examples.

[0115] In one embodiment of the present invention, the storage modulus (E') of the ionomer resin composition of the present invention at 50°C, as measured by dynamic viscoelasticity measurement, is preferably 20 MPa or more, more preferably 30 MPa or more, even more preferably 40 MPa or more, and particularly preferably 50 MPa or more, from the viewpoint of good self-supporting ability (i.e., high elastic modulus), particularly self-supporting ability in a high-temperature environment (high elastic modulus in a high-temperature environment). The upper limit of the storage modulus (E') is not particularly limited and may be 1000 MPa. The storage modulus can be adjusted by the molecular weight of the ionomer resin and the contents of the (meth)acrylic acid units (A), (meth)acrylic acid neutralized units (B), and ethylene units (C), as well as the (meth)acrylic acid ester units (D) optionally contained therein.

[0116] The ionomer resin composition of the present invention has high transparency. In one embodiment of the present invention, the haze of the ionomer resin composition of the present invention 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% or more. The haze of the ionomer resin composition is measured using a haze meter in accordance with JIS K7136:2000.

[0117] The present inventors discovered that while the inclusion of a salt of a strong acid and a strong base in an ionomer resin can improve the thermal decomposition resistance of the ionomer resin composition, an excessively high salt content reduces the transparency of the ionomer resin composition, particularly the transparency of the ionomer resin composition in a water-absorbed state (transparency upon water absorption). As a result of further investigation, the present inventors discovered that the transparency of the ionomer resin composition in a water-absorbed state can also be improved if the salt content in the ionomer resin is 400 mg / kg or less. Therefore, the ionomer resin composition of the present invention, in which the salt content in the ionomer resin is 1 to 400 mg / kg, has high transparency even when water is absorbed. In one embodiment of the present invention, the haze of the ionomer resin composition in a water-absorbed state (water-absorbed haze) is preferably 9.0% or less, more preferably 5.0% or less, even more preferably 3.0% or less, and particularly preferably 2.5% or less. Since the smaller the water absorption haze, the higher the transparency of the ionomer resin composition in a water-absorbed state, the lower limit is not particularly limited, and may be, for example, 0.01% or more. The water absorption haze can be measured using a haze meter in accordance with JIS K7136:2000, for example, by the method described in the Examples, using an ionomer resin composition as a test piece obtained by immersing the ionomer resin composition in ion-exchanged water at 23°C for 300 hours, removing it from the ion-exchanged water, and wiping off the water adhering to the surface.

[0118] According to the inventors' investigations, if the crystallinity of an ionomer resin is too high, the ionomer resin tends to whiten, and therefore the transparency (transparency upon slow cooling) of the ionomer resin composition when slowly cooled to promote crystallization of the ionomer resin is likely to decrease. However, the ionomer resin of the present invention is resistant to crystallization because the total content of (meth)acrylic acid units (A) and (meth)acrylic acid neutralized units (B) in the resin is 6 mol % or more, and therefore has high transparency even when slowly cooled. In a preferred embodiment of the present invention, the haze (slow cooling haze) of the ionomer resin composition of the present invention when slowly cooled to promote crystallization of the ionomer resin contained in the composition 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, so the lower limit is not particularly limited and may be, for example, 0.01% or more. The annealed haze can be obtained by preparing a laminated glass by placing a resin sheet formed from an ionomer resin composition as an interlayer between two glass plates, 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.

[0119] In one embodiment of the present invention, the ionomer resin composition of the present invention has a low degree of coloration, and is preferably colorless. From the viewpoint of low coloration, the yellowness index (YI) of the ionomer resin composition of the present invention is preferably 2.0 or less, more preferably 1.8 or less, even more preferably 1.5 or less, and particularly preferably 1.0 or less. Since the smaller the yellowness index (YI), the less coloration the ionomer resin composition has, the lower limit is not particularly limited and may be, for example, 0 or more. The yellowness index (YI) can be measured using a colorimeter in accordance with JIS Z8722:2009.

[0120] In one embodiment of the present invention, the adhesive strength of the ionomer resin composition of the present invention to glass is measured, for example, by the compression shear strength test described in WO 1999-058334. From the viewpoint of easily increasing the adhesive strength, the compressive shear strength is preferably 15 MPa or more, more preferably 20 MPa or more, and particularly preferably 25 MPa or more. Furthermore, from the viewpoint of easily increasing the penetration resistance of the laminated glass, the compressive shear strength may be 50 MPa or less.

[0121] In one embodiment of the present invention, the adhesiveness of the ionomer resin composition of the present invention to glass in a wet state can be evaluated by the glass adhesive strength of a resin sheet formed from the ionomer resin composition, measured by a peel test conducted in a wet state. The glass adhesive strength in a wet state is preferably 0.1 N / cm or more, more preferably 0.3 N / cm or more, even more preferably 0.7 N / cm or more, even more preferably 1.0 N / cm or more, and particularly preferably 1.2 N / cm or more. There is no particular upper limit, and it may be 10 N / cm or less. The adhesive strength can be measured using a tensile testing device, for example, by the method described in the Examples.

[0122] 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. The ionomer resin composition can be pelletized, for example, by cutting strands obtained by melt extrusion. When pelletizing by melt extrusion, the temperature of the resin composition during melt extrusion is preferably 150°C or higher, more preferably 170°C or higher, from the viewpoint of facilitating stable discharge from the extruder. Furthermore, the temperature is preferably 250°C or lower, more preferably 230°C or lower, from the viewpoint of preventing thermal decomposition and deterioration of the resin. Because the ionomer resin composition of the present invention has high thermal decomposition resistance, problems such as the thermal decomposition of the ionomer resin composition and the generation of black foreign matter are unlikely to occur when pelletizing by melt extrusion.

[0123] There are no particular limitations on the method for producing the ionomer resin composition of the present invention, and it can be produced, for example, by mixing an ionomer resin, a silane coupling agent, and optionally other additives.

[0124] The method for mixing the ionomer resin and the silane coupling agent is not particularly limited, and for example, the silane coupling agent may be directly added to the ionomer resin and mixed. In one embodiment of the present invention, the silane coupling agent may be added as part of a masterbatch of the ionomer resin, and the masterbatch and the ionomer resin may be mixed to adjust the content of the silane coupling agent in the ionomer resin composition. Furthermore, the silane coupling agent may be added during the pelletizing process or the molding process into a sheet, film, or the like.

[0125] The various additives may be added during the production of the ionomer resin, or may be added to the ionomer resin after the production of the ionomer resin, or may be added in the step of pelletizing the ionomer resin or the step of molding the ionomer resin into a sheet, film, or the like.

[0126] [Resin Sheet] The present invention also encompasses a resin sheet comprising one or more layers containing the ionomer resin composition of the present invention. Because the resin sheet of the present invention comprises a layer containing the resin composition of the present invention, it has excellent transparency and adhesion to substrates such as glass, and also has a good appearance with little black foreign matter, crosslinked gel, etc.

[0127] The resin sheet of the present invention includes one or more layers (hereinafter also referred to as layer (x)) containing the ionomer resin composition of the present invention. The resin sheet of the present invention may be composed of only layer (x), or may be a laminate including at least one layer (x). The laminate is not particularly limited, but examples thereof include a laminate including two or more layers (x), and a laminate including one or more layers (x) and one or more other layers. When layer (x) or other layers are multiple layers, the resins or resin compositions that constitute each layer may be the same or different.

[0128] Examples of the other layer include layers containing known resins. Examples of the resin include polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyurethane, polytetrafluoroethylene, acrylic resin, polyamide, polyacetal, polycarbonate, and polyesters such as polyethylene terephthalate, polybutylene terephthalate, cyclic polyolefin, polyphenylene sulfide, polytetrafluoroethylene, polysulfone, polyethersulfone, polyarylate, liquid crystal polymer, polyimide, and thermoplastic elastomer. Furthermore, the other layer may also contain one or more additives such as the additives described above, as well as plasticizers, pigments, dyes, heat-shielding materials (e.g., inorganic heat-shielding particles or organic heat-shielding materials having infrared absorbing properties), and functional inorganic compounds, if necessary.

[0129] In one embodiment of the present invention, from the viewpoint of excellent bubble removal properties when the resin sheet and the substrate are thermocompression bonded, the resin sheet of the present invention preferably has an uneven structure on the surface by a conventionally known method such as melt fracture or embossing. The shape of the melt fracture and embossing may be appropriately selected from conventionally known methods.

[0130] The thickness of each layer (x) in the resin sheet of the present invention is preferably 0.1 mm or more, more preferably 0.2 mm or more, even more preferably 0.3 mm or more, particularly preferably 0.4 mm or more, and is preferably 5 mm or less, more preferably 4 mm or less, even more preferably 2 mm or less, particularly preferably 1 mm or less. When the resin sheet has multiple layers (x), the thicknesses of the multiple layers (x) in the resin sheet may be the same or different.

[0131] 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.

[0132] The thickness of the resin sheet is measured by a conventionally known method, for example, using a contact or non-contact thickness meter, etc. The resin sheet may be in a state of being wound into a roll or in a state of individual sheets.

[0133] In a preferred embodiment of the present invention, the resin sheet of the present invention exhibits the same values ​​as the weight loss temperature, haze, water absorption haze, slow cooling haze, yellowness index, storage modulus at 50°C, adhesive strength, and adhesive strength in a wet state of the ionomer resin composition of the present invention described in the section [Ionomer Resin Composition].

[0134] The resin sheet of the present invention preferably has a low water content, from the viewpoint of being less likely to foam during the production of laminated glass. The water content of the resin sheet is preferably 1% by mass or less, more preferably 0.5% by mass or less, even more preferably 0.02% by mass or less, and particularly preferably 0.01% by mass or less. The water content can be measured by coulometric titration.

[0135] 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. Furthermore, if necessary, two or more layers (x), or one or more layers (x) and one or more other layers may be laminated by press molding or the like to form a laminated resin sheet. Alternatively, two or more layers (x), or one or more layers (x) and one or more other layers may be molded by co-extrusion to form a laminated resin sheet. When the layer (x) or other layers are multiple layers, the resin compositions constituting each layer may be the same or different.

[0136] Among known film-forming methods, a method of producing a resin sheet using an extruder is preferably used. The resin temperature during extrusion is preferably 150°C or higher, more preferably 170°C or higher, from the viewpoint of facilitating stabilization of the resin discharge from the extruder and reducing mechanical troubles. The resin temperature during extrusion is preferably 250°C or lower, more preferably 230°C or lower, from the viewpoint of 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 the vent port of the extruder by reducing pressure.

[0137] [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). Thus, 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 the laminated glass interlayer film of the present invention disposed between the two glass plates. The laminated glass of the present invention can have excellent transparency because it has a laminated glass interlayer film made of the resin sheet.

[0138] Examples of glass plates to be laminated with the interlayer film of the present invention include inorganic glass such as float glass, polished glass, figured glass, wired glass, and heat-absorbing glass, as well as conventionally known organic glass such as polymethyl methacrylate and polycarbonate. These may be 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.

[0139] The laminated glass of the present invention, which is obtained by sandwiching the resin sheet between two pieces of glass, 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, a method using a nip roll, etc. Another example is a method in which the glass sheets are temporarily pressure-bonded by the above method, and then placed in an autoclave for final bonding.

[0140] 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 Laminated glass can be produced by laminating glass sheets, an interlayer film, and any optional layers at 100 to 160° C. under a pressure of about 100 MPa.

[0141] 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.

[0142] When the laminated glass is subjected to pressure bonding by the above-mentioned method and then placed in an autoclave for further pressure bonding, the operating conditions for the autoclave step are appropriately selected depending on the thickness and 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.

[0143] The ionomer resin composition of the present invention and the resin sheet obtained from the resin composition have high transparency and high adhesion to glass, and therefore the laminated glass of the present invention has excellent transparency. In one embodiment of the present invention, the haze of the laminated glass of the present invention is preferably 1.0% or less, more preferably 0.8% or less, and even more preferably 0.5% or less. Since the smaller the haze, the higher the transparency of the laminated glass, the lower limit is not particularly limited and may be, for example, 0.01%. The haze of the laminated glass is measured using a haze meter in accordance with JIS K7136:2000.

[0144] The laminated glass of the present invention also has excellent transparency during annealing. The transparency during annealing can be evaluated by the haze during annealing (annealing haze). The annealing haze of the laminated glass of the present invention is preferably 5.0% or less, more preferably 4.5% 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 laminated glass, so the lower limit is not particularly limited and may be, for example, 0.01% or more. The annealing haze of the laminated glass is determined by 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 then measuring the haze using a haze meter in accordance with JIS K7136:2000, and can be determined, for example, by the method described in the Examples.

[0145] The laminated glass of the present invention is preferably little colored and as colorless as possible. The yellowness index (YI) of the laminated glass of the present invention is preferably 3.0 or less, more preferably 2.0 or less, even more preferably 1.5 or less, particularly preferably 1.0 or less, and may preferably be 0 or more. The yellowness index (YI) can be measured using a colorimeter in accordance with JIS Z8722.

[0146] The adhesive strength between the glass plates and the interlayer film in the laminated glass of the present invention is measured, for example, by the compression shear strength test described in WO 1999-058334. From the viewpoint of easily increasing the adhesive strength, the compressive shear strength is preferably 15 MPa or more, more preferably 20 MPa or more, and particularly preferably 25 MPa or more. Furthermore, from the viewpoint of easily increasing the penetration resistance of the laminated glass, the compressive shear strength may be 50 MPa or less.

[0147] The adhesion between the glass plates and the interlayer film in the laminated glass of the present invention in a wet state can be evaluated by the glass adhesion strength of the interlayer film measured by a peel test conducted in a wet state. The glass adhesion strength in a wet state is preferably 0.1 N / cm or more, more preferably 0.3 N / cm or more, even more preferably 0.7 N / cm or more, still more preferably 1.0 N / cm or more, and particularly preferably 1.2 N / cm or more. There is no particular upper limit, and it may be 10 N / cm or less. The adhesion strength can be measured using a tensile testing device, for example, by the method described in the Examples.

[0148] As described above, a resin sheet comprising one or more layers containing the ionomer resin composition of the present invention is useful as an interlayer film for laminated glass. The interlayer film for laminated glass is particularly preferred as an interlayer film for laminated glass for structural materials (facades) because of its excellent adhesion to substrates such as glass, transparency, and self-supporting ability.

[0149] Furthermore, the laminated glass of the present invention is not limited to being used as an interlayer film in laminated glass for structural materials, and can also be suitably used for automobile windshields, automobile side glass, automobile sunroofs, automobile rear glass, glass for head-up displays, laminates for exterior walls and 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.

[0150] 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.

[0151] [Contents of Monomer Units in Resins Obtained in Examples and Comparative Examples] For the ionomer resin compositions obtained in the examples and comparative examples, the contents of the (meth)acrylic acid units (A), (meth)acrylic acid neutralization product units (B), ethylene units (C), and (meth)acrylic acid ester units (D) in the ionomer resins were analyzed as follows.

[0152] The ionomer resin compositions obtained in the examples and comparative examples were each dissolved in a mixed solvent of dehydrated toluene / dehydrated acetic acid (75 / 25% by mass), reacted at 100°C for 2 hours, and then reprecipitated in a mixed solvent of acetone / water (80 / 20% by mass), thereby converting the (meth)acrylic acid neutralized unit (B) into the (meth)acrylic acid unit (A). The resulting resin was thoroughly washed with water and then dried, and the dried resin was subjected to the following (1) to (3). (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) The resin was subjected to precipitation 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, and then the type and amount of metal ions in the (meth)acrylic acid neutralization unit (B) were identified by ICP emission spectrometry (Thermo Fisher Scientific iCAP6500Duo). From the above (1), the 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 from the above (2) and (3), 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 unit (C) / (meth)acrylic acid ester unit (D) / (meth)acrylic acid unit (A) / (meth)acrylic acid neutralized product unit (B) was calculated from the information in (4) above. The content of each monomer unit in the raw material ethylene-(meth)acrylic acid ester copolymer (X) was measured by dissolving the copolymer in deuterated toluene or deuterated THF, １Measurements were performed using H-NMR (400 MHz, manufactured by JEOL Ltd.) and calculations were made.

[0153] [Content of Salts Composed of Strong Acids and Strong Bases in Ionomer Resin (Amount of Residual Inorganic Salts)] 0.1 g of the ionomer resin obtained in the Examples and Comparative Examples was weighed out, and 10 mL of ultrapure water was added to the resin. The resin was heated at 90°C for 1 hour. The resin was then allowed to cool and filtered through a filter with a mesh size of 0.45 μm. The filtrate obtained by filtration was used as a sample liquid and measured using an ion chromatograph (manufactured by Shimadzu Corporation) under the following conditions. The amount of chloride ions or sulfate ions was quantified based on the peak area obtained in the measurement, and the amount of chloride ions or sulfate ions was converted into the amount of sodium salt to determine the amount of residual inorganic salts. (Measurement Conditions) Eluent: Mixed solution of aqueous sodium carbonate solution (0.6 mmol / L) and aqueous sodium bicarbonate solution (12 mmol / L); Flow rate: 1.0 mL / min; Column temperature: 40°C; Column: IC-SA2 (250 L x 4.0)

[0154] [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 TG-DTA7200 simultaneous thermogravimetric differential thermal analyzer (manufactured by Hitachi High-Tech Science Corporation), the weight loss rate was measured when each resin composition was heated from 20°C to 550°C at a heating rate of 10°C / min in a nitrogen atmosphere with 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.

[0155] [Transparency upon water absorption (water absorption haze)] The resin sheets obtained in the examples and comparative examples were cut into 50 mm squares, and the cut samples were immersed in ion-exchanged water at 23° C. for 300 hours to obtain water-absorbed samples. After removing the water from the ion-exchanged water, the water adhering to the surface of the water-absorbed sample was wiped off, and the haze of the water-absorbed sample was measured in accordance with JIS K7136:2000 using a haze meter HZ-1 (manufactured by Suga Test Instruments Co., Ltd.).

[0156] [Transparency upon annealing (annealing haze)] The resin sheets obtained in the examples and comparative examples were sandwiched between two 2.7 mm thick float glass sheets, and a vacuum laminator (Nisshinbo Mechatronics Inc. 1522N) was used to reduce the pressure inside the vacuum laminator at 100 ° C. for 1 minute. The pressure was maintained at 30 kPa for 5 minutes while maintaining the reduced pressure and temperature, to obtain a temporary bonded body. The obtained 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 laminated glass obtained by the above method 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 the annealing operation was measured in accordance with JIS K7136:2000 using a haze meter HZ-1 (manufactured by Suga Test Instruments Co., Ltd.).

[0157] [Glass Adhesion Strength in Wet State] A 2.7 mm thick float glass was cut into a rectangle measuring 100 mm wide and 200 mm long, and its surface was cleaned. Two parallel strips of thin polyester tape (25 μm thick, 25 mm wide) with silicone adhesive were attached to the air side of the float glass, creating a uniform 25 mm-wide adhesive area between the polyester tape. A resin sheet (0.8 mm thick, 150 mm wide, 200 mm long) was placed on top of the adhesive area, and a 12 μm fluororesin film was then placed on top of the resin sheet. A piece of glass different from the float glass was then placed on the fluororesin film to provide a relatively flat surface for the lamination process, and the fluororesin film served as a release layer for removing the glass piece. The resulting temporarily bonded assembly was placed in an autoclave and treated at 140°C and 1.2 MPa for 30 minutes. The fluororesin film and the glass piece placed on it were then removed, yielding a peel test specimen in which two layers of float glass and an ionomer resin sheet were bonded together. Each sample was then subjected to a peel test at a 90° angle using a tensile testing machine (Shimadzu Autograph) to measure glass adhesion. The float glass surface and ionomer resin sheet were peeled at a head speed of 1 cm / min at 23°C and 50% RH. After peeling approximately 100 mm of the sample, ion-exchanged water was applied to the peeled interface between the float glass and the resin sheet, ensuring that the interface was completely immersed in liquid water. The peel speed was then reduced to 0.25 mm / min, and another 100 mm of the sample was peeled to evaluate glass adhesion. Sufficient water was present to ensure that the sample maintained a "wet" state during this test. The average wet glass adhesion value was recorded as the value.

[0158] [Raw Materials] In the Examples and Comparative Examples, the amount of methyl methacrylate (MMA) modification or the amount of ethyl acrylate (EA) modification, and the MFR of each ethylene-(meth)acrylic acid ester copolymer (X) used as a raw material 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.

[0159]

[0160] The silane coupling agents used in the examples and comparative examples are as follows: Silane coupling agent 1 (S1): 3-glycidoxypropylmethyldiethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) Silane coupling agent 2 (S2): N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.)

[0161] Example 1: 100 parts by mass of EMMA2 (Table 1) was placed in a stainless steel pressure vessel, and 233 parts by mass of toluene was added. The mixture was stirred at 60°C under a pressure of 0.02 MPa to dissolve the EMMA2. 96 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, after which 83 parts by mass of 20% by mass of hydrochloric acid was added, and the mixture was stirred at 50°C for 1 hour to convert some of the sodium methacrylate units to methacrylic acid, yielding a crude ionomer resin solution. A mixed solvent of toluene / methanol (75 / 25% by mass) was added to the resulting crude ionomer resin solution to a crude ionomer resin concentration of 10% by mass, thereby diluting the solution. Next, the temperature of the diluted solution of the obtained crude ionomer resin was adjusted to 34°C, and 430 parts by mass of methanol at 34°C was added to the diluted solution relative to 100 parts by mass of the crude ionomer resin solution to precipitate a granular resin. The obtained granular resin was then filtered, and 100 parts by mass of the filtered granular resin was mixed with 600 parts by mass of a water / methanol (50 / 50% by mass) mixed solvent. The slurry obtained by the above mixing was stirred at 40°C for 1 hour, and then the granular resin was filtered at room temperature. The granular resin was washed three more times with a water / methanol (50 / 50% by mass) mixed solvent to obtain washed ionomer resin 1. The obtained ionomer resin 1 was vacuum-dried for 8 hours or more, and then 100 parts by mass of the ionomer resin 1 and 0.15 parts by mass of the silane coupling agent (S1) were melt-kneaded at 210°C, and the melt-kneaded mixture was heated at 210°C and subjected to a pressure of 4.9 MPa (50 kgf / cm ２) for 5 minutes to obtain a 0.8 mm thick ionomer resin sheet 1. The analysis and evaluation results of the ionomer resin sheet 1 are shown in Table 2.

[0162] Example 2 Ionomer resin 2 was obtained in the same manner as in Example 1, except that EMMA3 was used instead of EMMA2 and the temperature of the diluted solution of crude ionomer resin and methanol was changed from 34°C to 37°C. 100 parts by mass of ionomer resin 2 and 0.06 parts by mass of silane coupling agent (S1) were melt-kneaded at 210°C, and the melt-kneaded mixture was heated at 210°C under a pressure of 4.9 MPa (50 kgf / cm ２ ) for 5 minutes to obtain a 0.8 mm thick ionomer resin sheet 2. The analysis and evaluation results of the obtained ionomer resin sheet 2 are shown in Table 2.

[0163] Example 3 Ionomer resin 3 was obtained in the same manner as in Example 1, except that EMMA3 was used instead of EMMA2 and the temperature of the diluted solution of crude ionomer resin and methanol was changed from 34°C to 40°C. 100 parts by mass of ionomer resin 3 and 0.10 parts by mass of silane coupling agent (S2) were melt-kneaded at 210°C, and the melt-kneaded mixture was heated at 210°C under a pressure of 4.9 MPa (50 kgf / cm ２ ) for 5 minutes to obtain a 0.8 mm thick ionomer resin sheet 3. The analysis and evaluation results of the obtained ionomer resin sheet 3 are shown in Table 2.

[0164] Example 4 Ionomer resin 4 was obtained in the same manner as in Example 3, except that 220 parts by mass of sulfuric acid (30% by mass) was added instead of hydrochloric acid. 100 parts by mass of ionomer resin 4 and 0.25 parts by mass of silane coupling agent (S2) were melt-kneaded at 210°C, and the melt-kneaded mixture was heated at 210°C and subjected to a pressure of 4.9 MPa (50 kgf / cm ２ ) for 5 minutes to obtain a 0.8 mm thick ionomer resin sheet 4. The analysis and evaluation results of the obtained ionomer resin sheet 4 are shown in Table 2.

[0165] Example 5 Ionomer resin 5 was obtained in the same manner as in Example 1, except that EEA1 was used instead of EMMA2, the concentration of the diluted solution of crude ionomer resin was changed from 10% by mass to 6% by mass, and the temperatures of the diluted solution of crude ionomer resin and methanol were changed from 34°C to 41°C. 100 parts by mass of ionomer resin 5 and 0.10 parts by mass of silane coupling agent (S2) were melt-kneaded at 210°C, and the melt-kneaded mixture was heated at 210°C under a pressure of 4.9 MPa (50 kgf / cm ２ ) for 5 minutes to obtain a 0.8 mm thick ionomer resin sheet 5. The analysis and evaluation results of the obtained ionomer resin sheet 5 are shown in Table 2.

[0166] Example 6 Ionomer resin 6 was obtained in the same manner as in Example 1, except that EMMA1 was used instead of EMMA2, the amount of sodium hydroxide methanol solution (20% by mass) added was changed from 96 parts by mass to 73 parts by mass, the amount of hydrochloric acid (20% by mass) added was changed from 83 parts by mass to 63 parts by mass, and the temperature of the diluted solution of crude ionomer resin and methanol was changed from 34°C to 37°C. 100 parts by mass of ionomer resin 6 and 0.40 parts by mass of silane coupling agent (S2) were melt-kneaded at 210°C, and the melt-kneaded mixture was heated at 210°C and subjected to a pressure of 4.9 MPa (50 kgf / cm ２ ) for 5 minutes to obtain a 0.8 mm thick ionomer resin sheet 6. The analysis and evaluation results of the obtained ionomer resin sheet 6 are shown in Table 2.

[0167] Example 7 Ionomer resin 3 was obtained in the same manner as in Example 3, and then 0.12 parts by mass of a silane coupling agent (S2) and 0.1 parts by mass of an ultraviolet absorber [2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol (manufactured by BASF; trade name: TINUVIN 329)] were added to 100 parts by mass of the ionomer resin 3, and the mixture was melt-kneaded at 210°C. The melt-kneaded mixture was heated at 210°C and subjected to a pressure of 4.9 MPa (50 kgf / cm ２ ) for 5 minutes to obtain a 0.8 mm thick ionomer resin sheet 7. The analysis and evaluation results of the ionomer resin sheet 7 are shown in Table 2.

[0168] Example 8 Ionomer resin 8 was obtained in the same manner as in Example 1, except that EMMA3 was used instead of EMMA2 and the temperature of the diluted solution containing the crude ionomer resin and methanol was changed from 34°C to 41°C. 100 parts by mass of ionomer resin 8 and 0.11 parts by mass of silane coupling agent (S1) were melt-kneaded at 210°C, and the melt-kneaded mixture was heated at 210°C and subjected to a pressure of 4.9 MPa (50 kgf / cm ２ ) for 5 minutes to obtain a 0.8 mm thick ionomer resin sheet 8. The analysis and evaluation results of the obtained ionomer resin sheet 8 are shown in Table 2.

[0169] Example 9 Ionomer resin 9 was obtained in the same manner as in Example 1, except that EMMA3 was used instead of EMMA2, 147 parts by mass of sulfuric acid (30% by mass) was used instead of 83 parts by mass of hydrochloric acid (20% by mass), and the temperature of the diluted solution containing the crude ionomer resin and methanol was changed from 34°C to 41°C. 100 parts by mass of ionomer resin 9 and 0.09 parts by mass of silane coupling agent (S1) were melt-kneaded at 210°C, and the melt-kneaded mixture was heated at 210°C and subjected to a pressure of 4.9 MPa (50 kgf / cm ２ ) for 5 minutes to obtain a 0.8 mm thick ionomer resin sheet 9. The analysis and evaluation results of the obtained ionomer resin sheet 9 are shown in Table 2.

[0170] Comparative Example 1 Ionomer resin 10 was obtained in the same manner as in Example 1, except that the temperature of the diluted solution of crude ionomer resin and methanol was changed from 34° C. to 43° C. 100 parts by mass of ionomer resin 10 and 0.10 parts by mass of silane coupling agent (S1) were melt-kneaded at 210° C., and the melt-kneaded mixture was heated at 210° C. under a pressure of 4.9 MPa (50 kgf / cm ２ ) for 5 minutes to obtain a 0.8 mm thick ionomer resin sheet 10. The analysis and evaluation results of the obtained ionomer resin sheet 10 are shown in Table 2.

[0171] Comparative Example 2 Ionomer resin 11 was obtained in the same manner as in Example 1, except that the temperature of the diluted solution of crude ionomer resin and methanol was changed from 34° C. to 46° C. 100 parts by mass of ionomer resin 11 and 0.10 parts by mass of silane coupling agent (S1) were melt-kneaded at 210° C., and the melt-kneaded mixture was heated at 210° C. under a pressure of 4.9 MPa (50 kgf / cm ２ ) for 5 minutes to obtain a 0.8 mm thick ionomer resin sheet 11. The analysis and evaluation results of the obtained ionomer resin sheet 11 are shown in Table 2.

[0172] Comparative Example 3 Ionomer resin 12 was obtained in the same manner as in Example 1, except that 220 parts by mass of sulfuric acid (30% by mass) was added instead of hydrochloric acid, and the temperature of the diluted solution of crude ionomer resin and methanol was changed from 34°C to 50°C. 100 parts by mass of ionomer resin 12 and 0.10 parts by mass of silane coupling agent (S1) were melt-kneaded at 210°C, and the melt-kneaded mixture was heated at 210°C and subjected to a pressure of 4.9 MPa (50 kgf / cm ２ ) for 5 minutes to obtain a 0.8 mm thick ionomer resin sheet 12. The analysis and evaluation results of the obtained ionomer resin sheet 12 are shown in Table 2.

[0173] Comparative Example 4 Ionomer resin 13 was obtained in the same manner as in Example 1, except that EMMA3 was used instead of EMMA2, the crude ionomer resin solution was reprecipitated in 500 parts by mass of a mixed solvent of acetone / water (80 / 20% by mass) relative to 100 parts by mass of the crude ionomer resin, and the resulting granular resin was washed three times with a mixed solvent of acetone / water (20 / 80% by mass). 100 parts by mass of ionomer resin 13 and 0.10 parts by mass of silane coupling agent (S2) were melt-kneaded at 210°C, and the melt-kneaded mixture was heated at 210°C under a pressure of 4.9 MPa (50 kgf / cm ２ ) for 5 minutes to obtain a 0.8 mm thick ionomer resin sheet 13. The analysis results and evaluation results of the obtained ionomer resin sheet 13 are shown in Table 2.

[0174] Comparative Example 5 Ionomer resin 14 was obtained in the same manner as in Example 1, except that EMMA4 was used instead of EMMA2, the amount of the methanol solution of sodium hydroxide (20% by mass) added was changed from 96 parts by mass to 66 parts by mass, and the amount of hydrochloric acid (20% by mass) added was changed from 83 parts by mass to 57 parts by mass. 100 parts by mass of ionomer resin 14 and 0.10 parts by mass of silane coupling agent (S2) were melt-kneaded at 210°C, and the melt-kneaded mixture was heated at 210°C and subjected to a pressure of 4.9 MPa (50 kgf / cm ２ ) for 5 minutes to obtain a 0.8 mm thick ionomer resin sheet 14. The analysis and evaluation results of the obtained ionomer resin sheet 14 are shown in Table 2.

[0175] Comparative Example 6 Ionomer resin 3 was obtained in the same manner as in Example 3, and then 100 parts by mass of the ionomer resin 3 was melt-kneaded at 210°C. The melt-kneaded mixture was heated at 210°C and subjected to a pressure of 4.9 MPa (50 kgf / cm ２ ) for 5 minutes to obtain a 0.8 mm thick ionomer resin sheet 15. The analysis and evaluation results of the ionomer resin sheet 15 are shown in Table 2.

[0176] Comparative Example 7 Ionomer resin 3 was obtained in the same manner as in Example 3, and then 100 parts by mass of the ionomer resin 3 and 1.0 part by mass of a silane coupling agent (S2) were melt-kneaded at 210°C. The melt-kneaded mixture was heated at 210°C and subjected to a pressure of 4.9 MPa (50 kgf / cm ２ ) for 5 minutes, but gelation occurred and it was not possible to obtain an ionomer resin sheet with a smooth surface.

[0177]

[0178] As shown in Table 2, the ionomer resin compositions obtained in Examples 1 to 9 were confirmed to have a high 1% weight loss temperature (Td1), low water absorption haze and annealing haze, high transparency, and high glass adhesion in a wet state. Furthermore, the resin sheets produced using the ionomer resin compositions obtained in the Examples had little black foreign matter or gelled matter, and had good surface smoothness and appearance. In contrast, the ionomer resin compositions obtained in Comparative Examples 1 to 7 showed poor results in at least one of the 1% weight loss temperature, water absorption haze, annealing haze, and glass adhesion in a wet state.

Claims

1. An ionomer resin composition comprising an ionomer resin and a silane coupling agent, wherein the ionomer resin contains (meth)acrylic acid units (A), (meth)acrylic acid neutralized units (B) and ethylene units (C), 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, and the content of salts composed of strong acids and strong bases in the ionomer resin is 1 to 400 mg / kg, and the content of the silane coupling agent is 0.005 to 0.5 parts by mass with respect to 100 parts by mass of the ionomer resin. The ionomer resin composition.

2. The ionomer resin further contains (meth)acrylate 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 ionomer resin composition according to Claim 1.

3. The salt composed of the strong acid and the strong base is a metal salt of an alkali metal and / or an alkaline earth metal. The ionomer resin composition according to Claim 1.

4. The salt composed of the strong acid and the strong base is a salt composed of at least one cation selected from the group consisting of sodium ions and potassium ions and at least one anion selected from the group consisting of halogen ions, nitrate ions and sulfate ions. The ionomer resin composition according to Claim 1.

5. The silane coupling agent is at least one silane coupling agent selected from the group consisting of amino compounds, glycidoxy compounds, sulfide compounds, mercapto compounds, vinyl compounds, nitro compounds and chloro compounds. The ionomer resin composition according to Claim 1.

6. The silane coupling agent is at least one silane coupling agent selected from the group consisting of N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane and 3-glycidoxypropylmethyldiethoxysilane. The ionomer resin composition according to Claim 1.

7. A resin sheet comprising one or more layers containing the ionomer resin composition according to any one of Claims 1 to 6.

8. An insulating glass interlayer comprising the resin sheet according to Claim 7.

9. A laminated glass having two glass plates and the laminated glass intermediate film according to claim 8 disposed between the two glass plates.