Resin sheet having layer that contains ionomer resin composition, and laminated glass

Abstract

The present invention relates to a resin sheet which has one or more layers that contain an ionomer resin composition, wherein: one of the layers that contain an ionomer resin composition forms at least one surface of the resin sheet; the surface has a contact angle of 60 to 75 degrees as determined in accordance with JIS K6768; the ionomer resin composition contains an ionomer resin that has a (meth)acrylic acid unit (A), a neutralized (meth)acrylic acid unit (B) and an ethylene unit (C), and a salt that is formed of a strong acid and a strong base; the total content of the unit (A) and the unit (B) is 6 to 10% by mole based on all monomer units of the ionomer resin; and the content of the salt is 1 to 400 mg / kg based on the total mass of the ionomer resin composition.

Description

Resin sheet and laminated glass having a layer comprising an ionomer resin composition

[0001] This patent application claims priority under the Paris Convention to Japanese Patent Application No. 2021-104270 (filing date: June 23, 2021), the entire contents of which are incorporated herein by reference. The present invention relates to a resin sheet having one or more layers comprising an ionomer resin composition, a laminated glass interlayer film comprising the resin sheet, and laminated glass having the laminated glass interlayer film.

[0002] Ionomer resins, which are neutralized ethylene-unsaturated carboxylic acid copolymers, are used as interlayer films in laminated glass due to their excellent transparency and adhesion to glass (see, for example, Patent Document 1). It is known that the adhesion of ionomer resins to float glass is poorer on the air side than on the tin side.

[0003] A known method for improving the adhesion of an ionomer resin sheet to glass is to prime the surface of the glass with a silane, organic amine (aliphatic amine, ethanolamine, etc.), or diisocyanate-type coupling agent before bonding the ionomer resin sheet to the glass. For example, Patent Document 2 describes a method for improving the adhesion of an ionomer resin sheet to the glass by using a glass sheet coated with an alcohol solution of a metal chelate.

[0004] Patent Document 3 describes a resin composition containing an ionomer resin and an adhesion promoter, wherein the adhesion promoter is a dialkoxysilane compound.

[0005] Patent Documents 4 and 5 describe laminated molded articles in which the surface of an ionomer resin sheet is modified by subjecting it to an oxidation treatment such as corona treatment or ozone treatment to improve the printability or interlayer adhesion.

[0006] U.S. Patent No. 6432522, JP 9-227177, WO 2019 / 027865, JP 4-64441, JP 2006-52303

[0007] However, the inventors' studies have revealed that the laminated glass described in Patent Document 2 has large variations in adhesiveness and insufficient adhesion to the air side. Furthermore, the resin composition described in Patent Document 3 is sometimes required to have improved adhesion to the air side. Furthermore, the laminated molded products described in Patent Documents 4 and 5 do not have the adhesiveness required for laminated glass. Furthermore, in recent years, demands for laminated glass have increased, and laminated glass having a laminated glass interlayer using an ionomer resin is now required to maintain high transparency, regardless of the manufacturing conditions of the laminated glass. Therefore, an object of the present invention is to provide a resin sheet that has excellent transparency in addition to excellent adhesion to glass.

[0008] The present inventors conducted extensive research to solve the above-mentioned problems, and as a result, have completed the present invention. Specifically, the present invention includes the following: [1] A resin sheet having one or more layers comprising an ionomer resin composition, wherein the layer comprising the ionomer resin composition forms at least one surface of the resin sheet, and the contact angle of the surface measured in accordance with JIS K6768 is 60 to 75 degrees, the ionomer resin composition comprising an ionomer resin containing (meth)acrylic acid units (A), (meth)acrylic acid neutralized units (B), and ethylene units (C), and a salt formed from a strong acid and a strong base, 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, and the content of the salt being 1 to 400 mg / kg based on the total mass of the ionomer resin composition. [2] The resin sheet according to [1], wherein layers containing the ionomer resin composition form both surfaces of the resin sheet, and the contact angles of both surfaces measured in accordance with JIS K6768 are 60 to 75 degrees. [3] The resin sheet according to [1] or [2], wherein the ionomer resin further contains (meth)acrylic acid ester units (D), and the total content of the units (A), (B), and (D) is 6 to 10 mol% based on the total monomer units constituting the ionomer resin. [4] The resin sheet according to any of [1] to [3], wherein the salt is a metal salt of an alkali metal and / or alkaline earth metal. [5] The resin sheet according to any of [1] to [4], wherein the salt 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. [6] A laminated glass interlayer film comprising the resin sheet according to any of [1] to [5]. [7] A laminated glass having two glass plates and the laminated glass interlayer film according to [6] disposed between the two glass plates.

[0009] According to the present invention, a resin sheet having excellent transparency in addition to excellent adhesion to glass can be provided.

[0010] [Resin Sheet] The resin sheet of the present invention has one or more layers (hereinafter also referred to as layer (x)) comprising an ionomer resin composition. The layer (x) forms at least one surface of the resin sheet, and the contact angle of the surface measured in accordance with JIS K6768 is 60 to 75 degrees. In a preferred embodiment of the present invention, the layer (x) forms both surfaces of the resin sheet, and the contact angle of both surfaces measured in accordance with JIS K6768 is 60 to 75 degrees.

[0011] The resin sheet of the present invention exhibits excellent adhesion to glass when the contact angle is 60 degrees or more and 75 degrees or less. Surprisingly, it has been found that this excellent adhesion is exhibited not only to tin surfaces but also to air surfaces. The contact angle is preferably 61 degrees or more, more preferably 62 degrees or more, and preferably 74 degrees or less, more preferably 73 degrees or less. When the contact angle is equal to or more than the lower limit and equal to or less than the upper limit, better adhesion to glass is likely to be exhibited. More specifically, the contact angle is measured by the method described in the examples.

[0012] To obtain a desired contact angle, the resin sheet may be subjected to a surface treatment. Examples of the surface treatment include surface oxidation treatments such as corona treatment, plasma treatment, flame plasma treatment, and ozone treatment, and primer treatment in which a mixed liquid of a silane compound and an alcohol is applied. These surface treatments may be performed alone or in combination of two or more. Corona treatment is preferred as the surface treatment.

[0013] The method of corona treatment is not particularly limited, and either a batch method or an in-line method may be used. The dose of irradiation in the corona treatment can be controlled by the device output and / or the feed rate. From the viewpoint of easily controlling the contact angle within a suitable range, the dose of irradiation in the corona treatment is preferably 0.01 J / cm. ２ More preferably, 0.05 J / cm ２ or more, and more preferably 0.1 J / cm ２ or more, and preferably 50 J / cm ２or less, more preferably 40 J / cm ２ More preferably, 30 J / cm or less ２ The following is the result.

[0014] The resin sheet of the present invention may be composed of only one layer (x), or may be a laminate including at least one layer (x). The configuration of the laminate is not particularly limited. Examples include a laminate consisting of two or more layers (x), and a laminate including one or more layers (x) and one or more other layers. When the laminate includes multiple layers (x) or multiple other layers, the resins or resin compositions constituting each layer (x) or each other layer may be the same or different.

[0015] The other layer can be a layer containing a known resin.Examples of the resin include polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyurethane, polytetrafluoroethylene, acrylic resin, polyamide, polyacetal, polycarbonate, polyesters such as polyethylene terephthalate, polybutylene terephthalate, cyclic polyolefin, polyphenylene sulfide, polysulfone, polyethersulfone, polyarylate, liquid crystal polymer, polyimide, and thermoplastic elastomer.Furthermore, the other layer may contain one or more additives such as the additives exemplified in the section [Additives] below, as well as plasticizers, heat-shielding materials (for example, inorganic heat-shielding particles or organic heat-shielding materials having infrared absorption ability), and functional inorganic compounds, if necessary.

[0016] In a preferred embodiment of the present invention, from the viewpoint of excellent degassing properties when the resin sheet and glass are thermocompression-bonded, the resin sheet of the present invention preferably has an uneven structure on at least one surface, preferably both surfaces, which is imparted by a conventionally known method such as a melt fracture method or an embossing method. The shape of the melt fracture and embossing is not particularly limited, and conventionally known shapes may be appropriately selected.

[0017] The thickness of one layer (x) in the resin sheet of the present invention is preferably 0.1 mm or more, more preferably 0.2 mm or more, even more preferably 0.3 mm or more, particularly preferably 0.4 mm or more, and is preferably 5 mm or less, more preferably 4 mm or less, even more preferably 2 mm or less, particularly preferably 1 mm or less. When the resin sheet contains multiple layers (x), the thicknesses of the layers (x) may be the same or different.

[0018] 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.

[0019] The thickness of the resin sheet is measured by a conventionally known method, for example, using a contact or non-contact thickness meter, etc. The resin sheet may be in a state of being wound in a roll or in a state of being individual sheets.

[0020] Next, the components contained in the ionomer resin composition contained in the layer (x), namely, the ionomer resin and the salt of a strong acid and a strong base, will be described.

[0021] [Ionomer Resin] The ionomer resin of the present invention 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 the units (B) is 6 to 10 mol % based on all monomer units constituting the ionomer resin. In this specification, the term "unit" means a "structural unit derived from." For example, a (meth)acrylic acid unit refers to a structural unit derived from (meth)acrylic acid, a (meth)acrylic acid neutralized product unit refers to a structural unit derived from a (meth)acrylic acid neutralized product, and an ethylene unit refers to a structural unit derived from ethylene. In addition, in this specification, "(meth)acrylic acid" refers to methacrylic acid or acrylic acid.

[0022] If the total content exceeds the upper limit, it is difficult to suppress an increase in melt viscosity during molding of the ionomer resin composition, which may result in a decrease in molding processability of the ionomer resin composition. Furthermore, if the total content is less than the lower limit, the transparency of the ionomer resin composition, particularly the transparency when slowly cooling the ionomer resin to promote crystallization (hereinafter also referred to as "transparency upon slow cooling"), is likely to decrease. The total content is 6 mol% or more, preferably 6.5 mol% or more, more preferably 7.0 mol% or more, and even more preferably 7.5 mol% or more, from the viewpoint of easily improving the transparency (particularly the transparency upon slow cooling) and adhesion to glass of the ionomer resin composition. Furthermore, it is 10 mol% or less, preferably 9.9 mol% or less, and more preferably 9.5 mol% or less, from the viewpoint of easily achieving more favorable molding processability.

[0023] The total content of the units (A) and the units (B) can be adjusted by the method for preparing the ionomer resin. More specifically, when an ionomer resin is prepared using an ethylene-(meth)acrylic acid ester copolymer as a raw material by a method including a saponification reaction step and a demetallation reaction step of the copolymer, the total content can be adjusted by the degree of reactivity (conversion rate) of the saponification reaction and the demetallation reaction that convert the (meth)acrylic acid ester units in the ethylene-(meth)acrylic acid ester copolymer into (meth)acrylic acid units (A) and (meth)acrylic acid neutralized product units (B).

[0024] <(Meth)acrylic acid unit (A)> Examples of monomers constituting the (meth)acrylic acid unit (A) include acrylic acid and methacrylic acid, and from the viewpoints of heat resistance and adhesion to glass, methacrylic acid is preferred. The (meth)acrylic acid unit may be a single type or a combination of two or more types.

[0025] The content of the (meth)acrylic acid unit (A) in the ionomer resin is not particularly limited, as long as the total content of the unit (A) and the unit (B) is within the range of 6 to 10 mol % based on all monomer units constituting the ionomer resin. In one embodiment of the present invention, the content of the (meth)acrylic acid unit (A) in the ionomer resin is preferably 4.5 mol % or more, more preferably 5.0 mol % or more, even more preferably 5.5 mol % or more, particularly preferably 5.8 mol % or more, based on all monomer units constituting the ionomer resin, and is preferably 9.0 mol % or less, more preferably 8.5 mol % or less, even more preferably 8.0 mol % or less, particularly preferably 7.5 mol % or less. When the content of the unit (A) is equal to or greater than the lower limit, the ionomer resin composition is likely to have better transparency and adhesion to glass. When the content is equal to or less than the upper limit, better moldability is likely to be obtained.

[0026] <(Meth)acrylic acid neutralization unit (B)> The (meth)acrylic acid neutralization unit (B) is preferably a neutralization unit of the (meth)acrylic acid unit (A). The (meth)acrylic acid neutralization product is a (meth)acrylic acid in which the hydrogen ion of (meth)acrylic acid is replaced with a metal ion. Examples of the metal ion include ions of monovalent metals such as lithium, sodium, and potassium, and ions of polyvalent metals such as magnesium, calcium, zinc, aluminum, and titanium. Such metal ions may be used alone or in combination of two or more. For example, a combination of one or more monovalent metal ions and one or more divalent metal ions may be used.

[0027] The content of the (meth)acrylic acid neutralized 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 neutralized unit (B) is preferably 0.65 mol % or more, more preferably 1.0 mol % or more, even more preferably 1.5 mol % or more, particularly preferably 1.6 mol % or more, based on all monomer units constituting the ionomer resin, and is preferably 3.0 mol % or less, more preferably 2.7 mol % or less, even more preferably 2.6 mol % or less, particularly preferably 2.5 mol % or less. When the content of the unit (B) is equal to or greater than the lower limit, better transparency and better elastic modulus are easily obtained, and when it is equal to or less than the upper limit, an increase in melt viscosity during molding is easily suppressed.

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

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

[0030] <(Meth)acrylic acid ester units (D)> In addition to the (meth)acrylic acid units (A), the (meth)acrylic acid neutralization product units (B), and the ethylene units (C), the ionomer resin in the present invention preferably further contains (meth)acrylic acid ester units (D) from the viewpoint of easily obtaining higher transparency.

[0031] When the ionomer resin contains (meth)acrylic acid ester units (D), the total content of the units (A), (B), and (D) is preferably 6 to 10 mol % based on all monomer units constituting the ionomer resin, from the viewpoint of easily obtaining higher transparency (particularly transparency upon slow cooling). That is, in a preferred embodiment of the present invention, the ionomer resin contains (meth)acrylic acid units (A), (meth)acrylic acid neutralized units (B), ethylene units (C), and (meth)acrylic acid ester units (D), and the total content of the units (A), (B), and (D) is 6 to 10 mol % based on all monomer units constituting the ionomer resin. When the ionomer resin contains (meth)acrylic acid ester units (D), if the total content of the units (A), (B), and (D) is equal to or less than the upper limit, the increase in melt viscosity during molding of the ionomer resin composition is easily suppressed, thereby improving moldability of the ionomer resin composition. Furthermore, if the total content is equal to or greater than the lower limit, the ionomer resin composition is easily able to achieve higher transparency (particularly transparency upon slow cooling). When the ionomer resin contains (meth)acrylic acid ester units (D), the total content of the units (A), (B), and (D) is 6 mol% or more, preferably 6.5 mol% or more, more preferably 7.0 mol% or more, and even more preferably 7.5 mol% or more, from the viewpoint of achieving higher transparency (particularly transparency upon slow cooling) and higher adhesion to glass. Furthermore, from the viewpoint of moldability, the total content is 10 mol% or less, preferably 9.9 mol% or less, and more preferably 9.5 mol% or less.

[0032] The total content of the units (A), (B), and (D) can be adjusted by the raw materials of the ionomer resin. More specifically, when an ionomer resin is prepared using an ethylene-(meth)acrylic acid ester copolymer as a raw material by a method including a saponification reaction step and a demetallation reaction step of the copolymer, the total content can be adjusted by the amount of (meth)acrylic acid ester modification of the ethylene-(meth)acrylic acid ester copolymer, which is the raw material of the ionomer resin. Furthermore, as described in U.S. Patent No. 8,399,096, when an ionomer resin is prepared by polymerizing ethylene and (meth)acrylic acid as raw materials, the total content can be adjusted by the ratio of ethylene and (meth)acrylic acid to be copolymerized.

[0033] Examples of monomers constituting the (meth)acrylic acid ester unit (D) include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, t-butyl (meth)acrylate, amyl (meth)acrylate, isoamyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, pentadecyl (meth)acrylate, dodecyl (meth)acrylate, isobornyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, glycidyl (meth)acrylate, and allyl (meth)acrylate. Among these, from the viewpoint of transparency or heat resistance, preferred monomers are methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, and t-butyl (meth)acrylate, more preferred monomers are methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, and isobutyl (meth)acrylate, still more preferred monomers are methyl (meth)acrylate, n-butyl (meth)acrylate, and isobutyl (meth)acrylate, and particularly preferred monomer is methyl (meth)acrylate. These monomers may be used alone or in combination of two or more.

[0034] When the ionomer resin contains (meth)acrylic acid ester units (D), the content of the (meth)acrylic acid ester units (D) in the ionomer resin is not particularly limited. In one embodiment of the present invention, the content of the (meth)acrylic acid ester units (D) in the ionomer resin, based on all monomer units constituting the ionomer resin, is preferably more than 0 mol%, more preferably 0.01 mol% or more, even more preferably 0.05 mol% or more, particularly preferably 0.08 mol% or more, and is preferably 1.0 mol% or less, more preferably 0.7 mol% or less, and even more preferably 0.5 mol% or less. When the content of units (D) is at least the above-mentioned lower limit and at most the above-mentioned upper limit, the ionomer resin composition is likely to have higher transparency.

[0035] When the ionomer resin contains (meth)acrylic acid ester units (D), the content of the units (D) can be adjusted by the reactivity of the saponification reaction that converts the (meth)acrylic acid ester units (D) in the ethylene-(meth)acrylic acid ester copolymer into (meth)acrylic acid units (A), when the ionomer resin is prepared from an ethylene-(meth)acrylic acid ester copolymer as a raw material by a method that includes a saponification reaction step and a demetallation reaction step of the copolymer.

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

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

[0038] The contents of the (meth)acrylic acid units (A), (meth)acrylic acid neutralized units (B), and ethylene units (C), as well as the (meth)acrylic acid ester units (D) and other monomer units (e.g., units (A2) and units (B2)) contained in the ionomer resin of the present invention can be determined by first identifying the monomer units in the ionomer resin 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. The contents can also 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.

[0039] In one embodiment of the present invention, the degree of branching per 1,000 carbon atoms of the ionomer resin of the present invention is not particularly limited, and is preferably 5 to 30, and more preferably 6 to 20. The degree of branching can be adjusted by the temperature during polymerization of the ionomer resin; for example, when the ionomer resin is synthesized using an ethylene-(meth)acrylic acid ester copolymer as a raw material by a method including a saponification reaction step of the copolymer, by the polymerization temperature during synthesis of the ethylene-(meth)acrylic acid ester copolymer. The degree of branching per 1,000 carbon atoms can be measured by the DDMAS method using solid-state NMR.

[0040] From the viewpoint of easily improving the transparency and providing excellent adhesion to glass to the resulting ionomer resin composition, the content of the ionomer resin is preferably 90% by mass or more, more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more, relative to the total mass of the ionomer resin composition, and is also preferably less than 100% by mass, and more preferably 99.99% by mass or less.

[0041] [Salt of a Strong Acid and a Strong Base] The ionomer resin composition of the present invention comprises, in addition to an ionomer resin, a salt of a strong acid and a strong base (hereinafter simply referred to as "salt"). The salt content is 1 to 400 mg / kg based on the total mass of the ionomer resin composition. The inventors have discovered that when the resin sheet of the present invention satisfies the above-mentioned requirements of a contact angle of 60 to 75 degrees, the ionomer resin satisfies the above-mentioned requirements of a total content of (meth)acrylic acid units (A) and (meth)acrylic acid neutralized units (B) of 6 to 10 mol %, and the ionomer resin composition satisfies the requirements of 1 to 400 mg / kg of salt, the resin sheet can achieve high transparency in addition to high adhesion to glass (not only the tin side but also the air side). On the other hand, if any of the above three requirements is not satisfied, the resin sheet cannot achieve both high adhesion to glass and high transparency. The inventors also discovered that when the ionomer resin composition contains 1 to 400 mg / kg of salt, the ionomer resin composition can also achieve high thermal decomposition resistance. While the reason why the ionomer resin composition exhibits excellent thermal decomposition resistance when the ionomer resin composition contains a salt within the above range is unclear, it is believed that this is because the interaction between the salt and the (meth)acrylic acid units (A) in the ionomer resin prevents the (meth)acrylic acid units (A) in the ionomer resin from being detached due to heat. Surprisingly, both the adhesion to glass and the thermal decomposition resistance of the ionomer resin composition rapidly decrease when the salt content is less than 1 mg / kg, as will be shown in the comparative examples described below.

[0042] If the salt content exceeds the upper limit, the transparency of the ionomer resin composition tends to decrease. If the salt content is less than the lower limit, the thermal decomposition resistance decreases, making the ionomer resin composition more susceptible to thermal decomposition, for example, during molding and processing, and also decreasing adhesion to glass (particularly the air surface). From the viewpoint of easily improving thermal decomposition resistance, the salt content is preferably 3 mg / kg or more, more preferably 5 mg / kg or more, based on the total mass of the ionomer resin composition. Furthermore, from the viewpoint of easily improving transparency (particularly transparency upon water absorption), the salt content is preferably 380 mg / kg or less, more preferably 340 mg / kg or less, even more preferably 300 mg / kg or less, and particularly preferably 200 mg / kg or less, based on the total mass of the ionomer resin composition. The salt content in the ionomer resin composition can be measured using ion chromatography, for example, by the method described in the Examples.

[0043] The salt is 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, 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.

[0044] From the viewpoint of easily increasing the thermal decomposition resistance of the ionomer resin composition, a more preferred salt is a salt composed 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 an even more preferred salt 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, sulfate ions, and nitrate ions.

[0045] 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, more preferred salts are sodium chloride, potassium chloride, sodium sulfate, potassium sulfate, sodium nitrate, and potassium nitrate, and even more preferred salts are sodium chloride, sodium sulfate, and sodium nitrate.

[0046] The method for incorporating a salt into an ionomer resin composition is not particularly limited, and examples thereof include (I) a method in which a salt is generated in the preparation step of an ionomer resin to obtain an ionomer resin composition containing the ionomer resin and the salt, (II) a method in which a salt is added separately in the preparation step of an ionomer resin to obtain an ionomer resin composition, and (III) a method in which a salt-free ionomer resin is prepared and a salt is subsequently added to the resin to obtain an ionomer resin composition, etc. Of these methods, method (I) is preferred from the viewpoint that the salt can be easily dispersed uniformly in the ionomer resin composition, thereby facilitating improvements in transparency and thermal decomposition resistance.

[0047] The method for adjusting the salt content in the ionomer resin composition can be appropriately selected depending on the method for incorporating the salt. For example, when incorporating a salt by the method (I), the salt content can be adjusted by controlling the cleanliness of the resulting resin. More specifically, the salt content in the ionomer resin composition 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 a salt by the methods (II) and (III), the salt content in the ionomer resin composition can be adjusted by controlling the amount of salt added separately and the amount of salt added later, respectively.

[0048] The state of dispersion of the salt in the ionomer resin composition is not particularly limited, but from the viewpoint of easily improving adhesion to glass, transparency, and thermal decomposition resistance, it is preferable that the salt be uniformly dispersed in the ionomer resin composition.

[0049] [Additives] The ionomer resin composition of the present invention may further contain additives as necessary. Examples of additives that may be optionally contained include ultraviolet absorbers, antioxidants, antioxidants, heat degradation inhibitors, light stabilizers, anti-sticking agents, lubricants, mold release agents, polymer processing aids, antistatic agents, flame retardants, dyes, pigments, organic dyes, matting agents, and fluorescent materials. Among these additives, ultraviolet absorbers, antioxidants, antioxidants, heat degradation inhibitors, light stabilizers, anti-sticking agents, lubricants, mold release agents, polymer processing aids, and organic dyes are preferred. When the ionomer resin composition contains additives, the additives contained may be one type alone or two or more types in combination.

[0050] The ultraviolet absorber is a compound capable of absorbing ultraviolet rays, and mainly functions to convert light energy into heat energy. Examples of ultraviolet absorbers include benzophenones, benzotriazoles, triazines, benzoates, salicylates, cyanoacrylates, oxalic acid anilides, malonic acid esters, and formamidines. When using ultraviolet absorbers, they may be used alone or in combination of two or more.

[0051] 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. When benzotriazoles are used, they may be used alone or in combination of two or more.

[0052] 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. When triazines are used, they may be used alone or in combination of two or more.

[0053] Examples of the antioxidant include known agents. 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. When an antioxidant is used, it may be used alone or in combination of two or more.

[0054] 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. When an antioxidant is used, it may be used alone or in combination of two or more. 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.

[0055] When a combination of a phosphorus-based antioxidant and a hindered phenol-based antioxidant is used, 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.

[0056] 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). When a phosphorus-based antioxidant is used, it may be used alone or in combination of two or more.

[0057] 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), octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate (manufactured by BASF; trade name: IRGANOX 1076), etc. When a hindered phenol-based antioxidant is used, it may be used alone or in combination of two or more.

[0058] The thermal degradation inhibitor can prevent thermal degradation of the resin by capturing polymer radicals generated when the resin is exposed to high heat under substantially oxygen-free conditions. 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). When a thermal degradation inhibitor is used, it may be used alone or in combination of two or more.

[0059] A light stabilizer is a compound that functions to capture radicals generated mainly by oxidation due to light. Preferred examples of light stabilizers include hindered amines such as compounds having a 2,2,6,6-tetraalkylpiperidine skeleton. When a light stabilizer is used, it may be used alone or in combination of two or more.

[0060] Examples of anti-sticking agents include salts or esters of fatty acids, esters of polyhydric alcohols, inorganic salts, inorganic oxides, and particulate resins. Preferred examples of anti-sticking agents include calcium stearate, calcium carbonate, calcium sulfate, magnesium sulfate, barium sulfate, silicon dioxide (manufactured by Evonik; trade name: Aerosil), and particulate acrylic resins. When an anti-sticking agent is used, it may be used alone or in combination of two or more.

[0061] Examples of lubricants include stearic acid, behenic acid, stearamidic acid, methylene bisstearamide, hydroxystearic acid triglyceride, paraffin wax, ketone wax, octyl alcohol, and hydrogenated oil, etc. When a lubricant is used, it may be used alone or in combination of two or more.

[0062] Examples of the release agent include higher alcohols such as cetyl alcohol and stearyl alcohol, and glycerin higher fatty acid esters such as stearate monoglyceride and stearate diglyceride. When a release agent is used, it may be used alone or in combination of two or more.

[0063] Polymer processing aids typically use polymer particles with a particle size of 0.05 to 0.5 μm, which can be produced by emulsion polymerization. These polymer particles may be single-layer particles consisting of a polymer with a single composition ratio and a single intrinsic viscosity, or multi-layer particles consisting of two or more polymers with different composition ratios or intrinsic viscosities. When polymer processing aids are used, they may be used alone or in combination. Among these, 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, are preferred. 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.

[0064] As the organic dye, a compound having a function of converting ultraviolet light into visible light is preferably used. When using an organic dye, it may be used alone or in combination of two or more.

[0065] Examples of fluorescent materials include fluorescent pigments, fluorescent dyes, fluorescent white dyes, fluorescent brighteners, fluorescent bleaches, etc. When fluorescent materials are used, they may be used alone or in combination of two or more.

[0066] When these additives are added, the contents of the various additives can be appropriately selected within a range that does not impair the effects of the present invention, and the total content of the various additives is preferably 7 mass% or less, more preferably 5 mass% or less, and even more preferably 4 mass% or less, relative to the total mass of the ionomer resin composition.

[0067] The various additives may be added when the ionomer resin composition is produced, may be added after the ionomer resin composition is produced, or may be added when the resin sheet described below is produced.

[0068] The ionomer resin composition of the present invention may be in the form of pellets or the like to improve convenience during storage, transportation, or molding. When pelletizing the ionomer resin composition, for example, pelletization can be performed by cutting strands obtained by melt extrusion. When pelletizing by melt extrusion, the temperature of the ionomer resin composition during melt extrusion is preferably 150°C or higher, more preferably 170°C or higher, from the viewpoint of easily stabilizing discharge from the extruder. Furthermore, the temperature is preferably 250°C or lower, more preferably 230°C or lower, from the viewpoint of easily preventing thermal decomposition and deterioration of the ionomer resin. Because the ionomer resin composition of the present invention has high thermal decomposition resistance, problems such as the thermal decomposition of the ionomer resin and the generation of black foreign matter are unlikely to occur when pelletizing by melt extrusion.

[0069] [Method for Producing Ionomer Resin Composition] The method for producing the ionomer resin composition of the present invention is not particularly limited. The ionomer resin composition may be produced by any of the methods (I) to (III) described above as the method for incorporating a salt into the ionomer resin composition. Among the methods (I) to (III), method (I) is preferred, in that it produces a salt in the ionomer resin preparation step to obtain an ionomer resin composition containing the ionomer resin and the salt, because it facilitates uniform dispersion of the salt in the ionomer resin composition, thereby enabling improved adhesion to glass, transparency, and thermal decomposition resistance to be achieved. Hereinafter, method (I) will be described in detail.

[0070] An example of method (I) is 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 prepare 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 containing the obtained crude ionomer resin to precipitate granules containing the crude ionomer resin (hereinafter, also simply referred to as "granules") (step ii), and the precipitated granules are then washed with a washing liquid (step iii).

[0071] <Step (i)> Examples of the 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 demetallated with a strong acid to convert them into (meth)acrylic acid units. An example of a method other than 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 saponification in 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)). In Methods (1) and (2), a salt consisting 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 reaction. In Method (I), by leaving some of this salt behind, an ionomer resin composition containing an ionomer resin and a salt is obtained after the step (iii) described below.

[0072] Examples of monomers constituting the (meth)acrylic acid ester units of the ethylene-(meth)acrylic acid ester copolymer (X) include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, t-butyl (meth)acrylate, amyl (meth)acrylate, isoamyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, pentadecyl (meth)acrylate, dodecyl (meth)acrylate, isobornyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, glycidyl (meth)acrylate, and allyl (meth)acrylate. Of these, preferred monomers are methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, and t-butyl (meth)acrylate, more preferred monomers are methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, and isobutyl (meth)acrylate, still more preferred monomers are methyl (meth)acrylate, n-butyl (meth)acrylate, and isobutyl (meth)acrylate, and particularly preferred monomer is methyl (meth)acrylate. The monomers may be used alone or in combination of two or more.

[0073] Specific examples of the ethylene-(meth)acrylic acid ester copolymer (X) include ethylene-methyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-ethyl methacrylate copolymer, ethylene-n-propyl acrylate copolymer, ethylene-n-propyl methacrylate copolymer, ethylene-isopropyl acrylate copolymer, ethylene-isopropyl methacrylate copolymer, ethylene-n-butyl acrylate copolymer, ethylene-n-butyl methacrylate copolymer, ethylene-sec-butyl acrylate copolymer, and ethylene-sec-butyl methacrylate copolymer, etc. As these copolymers, commercially available products may be used, or copolymers synthesized by the high-temperature, high-pressure radical polymerization method described in US 2013 / 0274424, JP 2006-233059, or JP 2007-84743 may also be used. Examples of the commercially available products include "Aclift" (registered trademark) WD301F and WH401F manufactured by Sumitomo Chemical Co., Ltd., and "Rexpearl" (registered trademark) A4250 manufactured by Japan Polyethylene Corporation.

[0074] The content of (meth)acrylic acid ester units in the ethylene-(meth)acrylic acid ester copolymer (X) is preferably 6 mol% or more, more preferably 6.5 mol% or more, even more preferably 7 mol% or more, particularly preferably 7.5 mol% or more, and is preferably 10 mol% or less, more preferably 9.9 mol% or less, and even more preferably 9.5 mol% or less. The content of (meth)acrylic acid ester units in the copolymer (X) corresponds to the total content of (meth)acrylic acid units (A), (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 ionomer resin composition tends to have higher transparency, particularly transparency during slow cooling. When the content is at most the above-mentioned upper limit, the resulting ionomer resin composition tends to have better moldability. The content of the (meth)acrylic acid ester unit in the copolymer (X) can be adjusted by the copolymerization ratio of ethylene and the (meth)acrylic acid ester. This content can be determined by pyrolysis gas chromatography, nuclear magnetic resonance spectroscopy (NMR) and elemental analysis, similar to the contents of the (meth)acrylic acid unit (A), the (meth)acrylic acid neutralized unit (B), the ethylene unit (C), and the (meth)acrylic acid ester unit (D) if contained, and other monomer units (e.g., the unit (A2) and the unit (B2)) in the ionomer resin described above.

[0075] In one embodiment of the present invention, the melt flow rate (MFR) of the ethylene-(meth)acrylic acid ester copolymer (X), measured in accordance with JIS K7210-1:2014 under conditions of 190°C and 2.16 kg, is preferably 5 g / 10 min or more, more preferably 10 g / 10 min or more, even more preferably 50 g / 10 min or more, even more preferably 100 g / 10 min or more, and is preferably 400 g / 10 min or less, more preferably 350 g / 10 min or less, even more preferably 300 g / 10 min or less, and even more preferably 250 g / 10 min or less. When the MFR of the ethylene-(meth)acrylic acid ester copolymer (X) is at least the above-mentioned lower limit and at most the above-mentioned upper limit, the resulting ionomer resin composition is likely to have better moldability and higher strength. The MFR of the ethylene-(meth)acrylic acid ester copolymer (X) can be adjusted by the degree of polymerization and the content of (meth)acrylic acid ester units. The MFR can be measured, for example, by the method described in the Examples.

[0076] 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.

[0077] 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 ethylene-(meth)acrylic acid ester copolymer (X). The degree of branching can be adjusted by using the ethylene-(meth)acrylic acid ester copolymer (X) dissolved in deuterated orthodichlorobenzene, １３ It can be measured by carrying out the inverse gate decoupling method of C-NMR.

[0078] Examples of the alkali used in the saponification reaction in the methods (1) and (2) include strong bases such as sodium hydroxide, potassium hydroxide, and calcium hydroxide. From the viewpoints of solubility in the solvent used in the saponification reaction and economic efficiency, sodium hydroxide and potassium hydroxide are preferred. The alkali may be used alone or in combination of two or more.

[0079] 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.

[0080] 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.

[0081] 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, and is preferably carried out under elevated pressure.

[0082] Examples of acids used in the demetallization in the methods (1) and (2) include strong acids such as hydrochloric acid, nitric acid, sulfuric acid, and toluenesulfonic acid. Among these, preferred acids are inorganic acids such as hydrochloric acid, nitric acid, and sulfuric acid, from the viewpoint of facilitating removal of salts from the ionomer resin composition after demetallization. The acids may be used alone or in combination of two or more. The solvent used in the demetallization reaction may be the same as the solvent used in the saponification reaction described above.

[0083] 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.

[0084] The demetallation may be carried out in air or in an inert gas such as nitrogen gas or argon gas. The saponification reaction may be carried out under normal pressure, elevated pressure, or reduced pressure, and is preferably carried out under elevated pressure.

[0085] In the method (2), the neutralizing agent used when neutralizing a portion of the (meth)acrylic acid units to convert them into neutralized (meth)acrylic acid units is not particularly limited as long as it is an ionic compound containing a metal ion. Examples of the metal ion include ions of alkali metals such as lithium, potassium, and sodium, ions of alkaline earth metals such as magnesium and calcium, ions of transition metals such as zinc, nickel, iron, and titanium, and aluminum ions. For example, when the metal ion is a sodium ion, an example of the neutralizing agent is sodium hydroxide.

[0086] <Step (ii)> (Solution Containing Crude Ionomer Resin) 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 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. Furthermore, the crude ionomer resin may further contain other monomer units such as carboxylic acid units (A2) other than (meth)acrylic acid units and carboxylic acid neutralization units (B2) other than (meth)acrylic acid neutralization units, in addition to the units (A), (B), and (C), and optionally the units (D).

[0087] Examples of the units (A) and (B) in the crude ionomer resin, as well as the unit (D) and other monomer units (A2) and (B2) that may be contained in the crude ionomer resin, include the same units as those described above as the units (A), (B), (D), (A2), and (B2) 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 preferred forms.

[0088] The solution containing the crude ionomer resin 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 solution containing the crude ionomer resin.

[0089] The solvent for the solution containing the crude ionomer resin is not particularly limited as long as it is 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.

[0090] The concentration of the solution containing the crude ionomer resin is preferably 30% by mass or less, more preferably 15% by mass or less, and is also preferably 1% by mass or more, more preferably 5% by mass or more, from the viewpoint that particulate matter with a small particle size can be easily obtained and, as a result, the salt content in the ionomer resin composition described below can be easily adjusted to a predetermined range.

[0091] The temperature of the solution containing the crude ionomer resin is preferably equal to or lower than the melting point of the ionomer resin, more preferably equal to or lower than 60° C., and even more preferably equal to or lower than 50° C., from the viewpoint of easily suppressing aggregation or agglutination of the precipitated particulate matter and easily adjusting the salt content in the ionomer resin composition to within a range of 1 to 400 mg / kg. Furthermore, from the viewpoint of the fluidity of the solution containing the crude ionomer resin, the temperature is more preferably equal to or higher than 25° C., and even more preferably equal to or higher than 30° C.

[0092] (Poor Solvent) The poor solvent to be added to the solution containing the crude ionomer resin is not particularly limited as long as it is a solvent that, when mixed with the solution containing the crude ionomer resin, does not dissolve the ionomer resin. Examples of poor solvents include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, and 1-butanol; water; ketones such as acetone and methyl ethyl ketone; esters such as methyl acetate and ethyl acetate; ethers such as dimethyl ether, diethyl ether, and tetrahydrofuran; and hydrocarbon compounds such as n-hexane, cyclohexane, and heptane. The poor solvent may be used alone or in combination of two or more. Among these, from the viewpoints of facilitating drying of the ionomer resin composition due to its low boiling point and facilitating removal of salt from the granular material due to its ability to dissolve salt, 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.

[0093] The amount of the poor solvent added may be appropriately selected depending on the concentration of the solution containing the crude ionomer resin. 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 solution containing the crude ionomer resin. The upper limit of the amount of the poor solvent added is not particularly limited, and is usually 1,000 parts by mass or less, per 100 parts by mass of the solution containing the crude ionomer resin.

[0094] The method for adding the poor solvent to the solution containing the crude ionomer resin is not particularly limited. For example, the poor solvent may be added to the solution containing the crude ionomer resin all at once, or may be added in multiple portions by dropwise addition, etc. From the viewpoint that the particle size of the granules tends to be small, which tends to improve the removability of salts in the granules and, as a result, tends 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.

[0095] It is preferable to add a poor solvent to a solution containing a crude ionomer resin, and then stir the mixture of the solution containing the crude ionomer resin and the poor solvent. The stirring speed is not particularly limited, but the faster the stirring speed, the easier it is to obtain granules with a small particle size. The stirring time is not particularly limited, and it may be, for example, stirred until the granules precipitate and the mixture of the solution containing the crude ionomer resin and the poor solvent becomes a slurry. The specific 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.

[0096] (Granular Material) The peak-top particle size of the granular material precipitated by adding a poor solvent to a solution containing a crude ionomer resin is preferably 700 μm or less, more preferably 650 μm or less, even more preferably 600 μm or less, and particularly preferably 550 μm or less, from the viewpoint that increasing the specific surface area of ​​the granular material makes it easier to reduce the salt content in the granular material, thereby making it easier to adjust the salt content to within the range of 1 to 400 mg / kg. Furthermore, from the viewpoint that favorable filterability of the granular material can be easily obtained and the production efficiency of the ionomer resin can be easily improved, the peak-top particle size is preferably 50 μm or more, more preferably 70 μm or more, and even more preferably 80 μm or more. The peak-top particle size can be measured, for example, by laser diffraction / scattering method or single light scattering method.

[0097] The peak-top particle size of the granules precipitated by adding a poor solvent to a solution containing a crude ionomer resin can be adjusted by the concentration and temperature of the solution containing the crude ionomer resin. Specifically, lowering the concentration and / or temperature of the solution containing the crude ionomer resin reduces the peak-top particle size of the precipitated granules, while increasing the concentration and / or temperature of the solution containing the crude ionomer resin increases the peak-top particle size of the precipitated granules. The peak-top particle size of the granules can also be adjusted by the method of adding the poor solvent and the stirring speed of the mixture of the solution containing the crude ionomer resin and the poor solvent.

[0098] <Step (iii)> (Washing Liquid) The washing liquid in step (iii) is not particularly limited as long as it is a solvent that does not dissolve the ionomer resin and 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. The washing liquids may be used alone or in combination of two or more.

[0099] 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 granules. Furthermore, a more preferred cleaning solution is a mixture of water and alcohols, from the viewpoints of increasing salt solubility, making the specific gravity of the cleaning solution smaller than that of the granules, thereby increasing the contact area between the cleaning solution and the granules, thereby making it easier to remove salt, and also making it easier to remove impurities such as organic compounds contained in the granules, and making it easier to dry the ionomer resin composition obtained after washing. Preferred alcohols are methanol and ethanol, because they are easy to dry and have high compatibility with water, and more preferably methanol. The ratio of water to 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.

[0100] An example of a method for washing granules with a washing liquid is a method in which the granules are filtered out of the granule dispersion obtained in step (ii), the filtered granules are mixed with the washing liquid, and the liquid is then removed. More specifically, a washing method is exemplified in which the granules filtered out of the dispersion are mixed with the washing liquid, the granules are filtered out of the washing liquid (hereinafter also referred to as washing step (a)), the filtered granules are then mixed with new washing liquid, and the granules are filtered out of the washing liquid (hereinafter also referred to as washing step (b)). From the viewpoint of easily adjusting the salt content contained in the granules to within a range of 1 to 400 mg / kg and from the viewpoint of production efficiency of the ionomer resin, in the case of a batch process, the granules are preferably washed, for example, by performing one washing step (a) followed by one to ten washing steps (b); the number of washing steps (b) following one washing step (a) is more preferably one to six, and even more preferably one to four.

[0101] The amount of the cleaning solution used per washing step may be appropriately selected depending on the amount of granular material to be washed. For example, the amount of the cleaning solution used per washing step is preferably 100 to 2,000 parts by mass, more preferably 200 to 1,000 parts by mass, and even more preferably 300 to 700 parts by mass, per 100 parts by mass of the granular material on a dry basis.

[0102] The ionomer resin composition containing the ionomer resin and the salt obtained after step (iii) may be dried, if necessary. The drying temperature is preferably not higher than the melting point of the ionomer resin, more preferably not higher than 80° C. Drying may be performed under reduced pressure.

[0103] <Characteristics of Ionomer Resin Composition> As described above, the ionomer resin composition of the present invention exhibits high thermal decomposition resistance due to the inclusion of a specific amount of salt. As a result, the ionomer resin composition of the present invention can have a higher 1% weight loss temperature (Td1) and a lower degree of discoloration. The 1% weight loss temperature 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. The 1% weight loss temperature is typically 450°C or lower. When the 1% weight loss temperature of the ionomer resin composition is equal to or higher than the lower limit, foaming and / or thermal decomposition during melt molding of the ionomer resin composition is easily reduced, making it easier to obtain a resin sheet free of defects such as bubbles and / or black impurities caused by thermal decomposition of the resin. Note that, in this specification, the 1% weight loss temperature refers to the temperature at which the weight loss rate is 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. The ionomer resin composition of the present invention has a low degree of coloration, and is preferably colorless. The yellowness index (YI) of the ionomer resin composition of the present invention in a sheet having a thickness of 0.8 mm is preferably 2.0 or less, more preferably 1.8 or less, even more preferably 1.5 or less, and particularly preferably 1.0 or less. The lower the yellowness index, the less the colorability of the ionomer resin composition; therefore, the lower limit is not particularly limited and may be, for example, 0. The yellowness index can be measured using a colorimeter in accordance with JIS Z8722:2009.

[0104] As described above, the ionomer resin composition of the present invention has high transparency due to the inclusion of a specific amount of salt. The haze of a sheet of the ionomer resin composition of the present invention at a thickness of 0.8 mm is preferably 2.0% or less, more preferably 1.5% or less, and even more preferably 1.0% or less. Since the smaller the haze, the higher the transparency of the ionomer resin composition, the lower limit is not particularly limited and may be, for example, 0.01%. The haze of the ionomer resin composition is measured using a haze meter in accordance with JIS K7136:2000.

[0105] Furthermore, as described above, the ionomer resin composition of the present invention, due to the inclusion of a specific amount of salt, is excellent in transparency, particularly in transparency when the ionomer resin composition has absorbed water (transparency upon water absorption). The haze (water absorption haze) of a sheet of the ionomer resin composition of the present invention at a thickness of 0.8 mm when water is absorbed is preferably 9.0% or less, more preferably 5.0% or less, even more preferably 4.0% or less, and particularly preferably 3.0% or less. The smaller the water absorption haze, the higher the transparency of the ionomer resin composition when water is absorbed, so the lower limit is not particularly limited and may be, for example, 0.01%. The water absorption haze can be measured, for example, by the method described in the Examples.

[0106] According to the inventors' investigations, if the crystallinity of an ionomer resin is too high, the ionomer resin tends to whiten. Therefore, normally, when an ionomer resin is slowly cooled to promote its crystallization, its transparency (transparency upon slow cooling) tends to decrease. However, the ionomer resin of the present invention has a total content of (meth)acrylic acid units (A) and (meth)acrylic acid neutralized units (B) of 6 mol % or more, so the resin is less likely to crystallize even upon slow cooling. As a result, the ionomer resin composition of the present invention, which contains such an ionomer resin, can maintain high transparency even after the crystallization of the ionomer resin has been promoted by slow cooling. The haze (slow cooling haze) of the ionomer resin composition of the present invention after the crystallization of the ionomer resin has been promoted by slow cooling is preferably 5.0% or less, more preferably 4.5% or less, even more preferably 4.0% or less, even more preferably 3.0% or less, and particularly preferably 2.5% or less. Since the smaller the haze, the higher the transparency of the ionomer resin composition, the lower limit is not particularly limited and may be, for example, 0.01%. The annealed haze can be measured by placing a 0.8 mm-thick sheet of the ionomer resin composition between two glass plates to prepare a laminated glass, heating the laminated glass to 140°C, and then annealing it from 140°C to 23°C at a rate of 0.1°C / min, and measuring the haze after that using a haze meter in accordance with JIS K7136:2000.

[0107] In one embodiment of the present invention, the melting point of the ionomer resin composition of the present invention 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.

[0108] In one embodiment of the present invention, the heat of fusion of the ionomer resin composition of the present invention 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.

[0109] In one embodiment of the present invention, the melt flow rate (MFR) of the ionomer resin composition of the present invention, 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 is preferably 50 g / 10 min or less, more preferably 30 g / 10 min or less, and particularly preferably 10 g / 10 min or less. When the MFR of the ionomer resin composition is at least the above-mentioned lower limit and is at most the above-mentioned upper limit, molding processing is facilitated while suppressing deterioration due to heat, and a resin sheet with excellent penetration resistance is easily obtained.

[0110] The melting point, heat of fusion and MFR of the ionomer resin composition 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) of the ionomer resin, as well as the (meth)acrylic acid ester units (D) that may be contained in the ionomer resin.

[0111] 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 suitable 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), ethylene units (C), and optionally contained (meth)acrylic acid ester units (D).

[0112] [Method for Producing Resin Sheet] The method for producing the resin sheet of the present invention is not particularly limited. For example, after uniformly kneading the ionomer resin composition of the present invention, the layer (x) can be produced by a known film-forming method such as extrusion, calendaring, pressing, solution casting, melt casting, or inflation. The layer (x) may be used alone as a resin sheet. Alternatively, if necessary, two or more layers (x), or one or more layers (x) and one or more other layers may be laminated by press molding or the like to obtain a laminate, or two or more layers (x), or one or more layers (x) and one or more other layers may be molded by co-extrusion to obtain a laminate, which may then be used as a resin sheet. When the laminate contains multiple layers (x) or multiple other layers, the resins or resin compositions constituting each layer (x) or each other layer may be the same or different.

[0113] Among known film-forming methods, a method of producing a resin sheet using an extruder is preferably used. The resin temperature or resin composition temperature during extrusion is preferably 150°C or higher, more preferably 170°C or higher, from the viewpoint of facilitating stabilization of the resin discharge from the extruder and reducing mechanical troubles. The temperature is preferably 250°C or lower, more preferably 230°C or lower, from the viewpoint of facilitating reduction of resin decomposition and degradation of the resin associated with decomposition. In addition, in order to efficiently remove volatile substances, it is preferable to remove the volatile substances from the vent port of the extruder by reducing pressure. After producing a resin sheet by a known film-forming method, the resin sheet may be surface-treated to obtain a desired contact angle, as described above in the section [Resin Sheet].

[0114] The resin sheet of the present invention has high transparency, high thermal decomposition resistance, and excellent adhesion to glass due to the characteristics of the ionomer resin composition of the present invention. That is, in a preferred embodiment of the present invention, the resin sheet of the present invention can have haze, water absorption haze, annealing haze, storage modulus, 1% weight loss, and yellowness index equivalent to those of the ionomer resin composition of the present invention.

[0115] The adhesive strength between the resin sheet of the present invention and glass is measured, for example, by the compressive shear strength test described in WO 1999 / 058334. More specifically, it is measured by the method described in the Examples. The compressive shear strength of the tin side of the resin sheet of the present invention is preferably 25 MPa or more, more preferably 27 MPa or more, even more preferably 29 MPa or more, and particularly preferably 31 MPa or more. The compressive shear strength of the air side of the resin sheet of the present invention is preferably 25 MPa or more, more preferably 28 MPa or more, and particularly preferably 30 MPa or more. In addition, the compressive shear strength of the tin side or the air side may be 50 MPa or less, from the viewpoint of easily increasing the penetration resistance of the laminated glass.

[0116] The resin sheet of the present invention preferably has a low water content, for example, from the viewpoint that the resin sheet is less likely to foam during the production of laminated glass when used as an interlayer film for 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.

[0117] [Laminated Glass Interlayer Film and Laminated Glass] The resin sheet of the present invention can be suitably used as a laminated glass interlayer film (also simply referred to as an interlayer film). Accordingly, the present invention encompasses a laminated glass interlayer film made of the resin sheet of the present invention. The present invention also encompasses laminated glass having two glass plates and a laminated glass interlayer film of the present invention disposed between the two glass plates. Because the laminated glass of the present invention has a laminated glass interlayer film made of the resin sheet, it can have excellent transparency and excellent adhesion between the interlayer film and the glass.

[0118] The glass plates to be laminated with the interlayer film of the present invention may be, for example, inorganic glass such as float glass, polished plate glass, figured glass, wired plate glass, or heat-absorbing plate glass, as well as conventionally known organic glass such as polymethyl methacrylate or polycarbonate. These may be either colorless or colored. One type of these may be used, or two or more types may be used in combination. Furthermore, the thickness of one glass plate is preferably 100 mm or less, and the thicknesses of the two glass plates may be the same or different.

[0119] The laminated glass of the present invention can be produced by a conventionally known method. Examples of such methods include a method using a vacuum laminator, a method using a vacuum bag, a method using a vacuum ring, and a method using nip rolls. Another method involves pressure bonding using the above methods, followed by placing the glass in an autoclave for further bonding.

[0120] When using a vacuum laminator, for example, 1 × 10 －６ ~1 x 10 －１Laminated glass can be produced by laminating glass sheets, an interlayer film, and an optional layer (such as an adhesive resin layer) under a reduced pressure of 60 to 200°C, particularly 80 to 160°C, of ​​a pressure of about 2 × 10 MPa. A method using a vacuum bag or a vacuum ring is described, for example, in European Patent No. 1235683. －２ ~3 x 10 －２ A laminated glass can be produced by laminating a glass plate and an interlayer film at 100 to 160° C. under a reduced pressure of about 100 MPa.

[0121] 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.

[0122] When the laminated glass is placed in an autoclave and further pressure-bonded, the operating conditions for the autoclave step are appropriately selected depending on the thickness and / or configuration of the laminated glass. For example, it is preferable to treat the laminated glass under a pressure of 0.5 to 1.5 MPa at 100 to 160°C for 0.5 to 3 hours.

[0123] Because the ionomer resin composition of the present invention has high transparency, excellent thermal decomposition resistance, and high adhesion to glass, the laminated glass of the present invention has excellent transparency and heat resistance, and the laminated glass has high adhesion between the interlayer film and the glass. In one embodiment of the present invention, when the interlayer film sheet thickness is 0.8 mm, the haze of the laminated glass is preferably 1.0% or less, more preferably 0.8% or less, and even more preferably 0.5% or less. Since the transparency of the laminated glass increases with decreasing haze, 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.

[0124] In one embodiment of the present invention, the laminated glass of the present invention remains excellent in transparency even after being heated to 140°C and then slowly cooled from 140°C to 23°C at a rate of 0.1°C / min. The haze (slow-cooling haze) of a laminated glass having an interlayer sheet thickness of 0.8 mm after being heated to 140°C and then slowly cooled from 140°C to 23°C at a rate of 0.1°C / min is preferably 5.0% or less, more preferably 4.5% or less, even more preferably 4.0% or less, still 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, the lower limit is not particularly limited and may be, for example, 0.01%. The slow-cooling haze is also measured using a haze meter in accordance with JIS K7136:2000.

[0125] In one embodiment of the present invention, the laminated glass of the present invention preferably has a small coloration degree and is as colorless as possible. When the sheet thickness of the interlayer film is 0.8 mm, the yellowness index of the laminated glass 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, the less the colorability of the laminated glass, the lower limit is not particularly limited and may be, for example, 0. The yellowness index is measured using a colorimetric color difference meter in accordance with JIS Z8722:2009.

[0126] 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.

[0127] [Contents of Monomer Units in Resins in Examples and Comparative Examples] For the ionomer resin compositions or ionomer resins 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.

[0128] The ionomer resin compositions or ionomer resins obtained in the examples and comparative examples were dissolved in a mixed solvent of dehydrated toluene / dehydrated acetic acid (75 / 25% by mass), reacted at 100°C for 2 hours, and then reprecipitated in a mixed solvent of acetone / water (80 / 20% by mass), thereby converting the (meth)acrylic acid neutralized units (B) into (meth)acrylic acid units (A). The resulting mixture was then thoroughly washed with water and dried, after which the following steps (1) to (3) were carried out. (1) The components of the monomer units constituting the resin were analyzed by pyrolysis GC-MS. (2) The acid value of the resin was measured in accordance with JIS K0070:1992. (3) The acid value of the resin was measured 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 or ionomer resins obtained in the examples and comparative examples were each subjected to microwave decomposition pretreatment with nitric acid, followed by ICP emission spectrometry (Thermo Fisher Scientific iCAP6500Duo) to identify the type and amount of metal ions in the (meth)acrylic acid neutralization unit (B). From the information in (1) above, the type and structure of the (meth)acrylic acid ester unit (D) and the (meth)acrylic acid unit (A) were identified. From this information and the information in (2) and (3) above, the ratio of ethylene unit (C) / (meth)acrylic acid ester unit (D) / (total of (meth)acrylic acid unit (A) and (meth)acrylic acid neutralization unit (B)) was calculated. Furthermore, the ratio of ethylene 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). The content of each monomer unit in the raw material ethylene-(meth)acrylic acid ester copolymer (X) was determined by dissolving the ethylene-(meth)acrylic acid ester copolymer (X) in deuterated toluene or deuterated THF, １Measurements were performed using H-NMR (400 MHz, manufactured by JEOL Ltd.) and calculations were made. Note that, since the content of the monomer units of the resin does not change during the process of producing a resin sheet from the ionomer resin composition or ionomer resin, the calculated content of each monomer unit of each resin corresponds to the content of each monomer unit of the corresponding resin sheet.

[0129] [Content of Salts Composed of Strong Acids and Strong Bases] 0.1 g of the ionomer resin composition or ionomer resin obtained in the Examples and Comparative Examples was weighed out, 10 mL of ultrapure water was added, and the mixture was heated at 90°C for 1 hour. The mixture was then allowed to cool and filtered through a filter with a mesh size of 0.45 µm. The filtrate obtained by filtration was used as a sample liquid and measured using an ion chromatograph (manufactured by Shimadzu Corporation) under the following conditions. The amount of chloride ions or sulfate ions was quantified from the peak area obtained by the measurement, and the amount of chloride ions or sulfate ions was converted to the amount of sodium salt to determine the salt content. (Measurement conditions) Eluent: mixed solution of aqueous sodium carbonate solution (0.6 mmol / L) and aqueous sodium hydrogencarbonate solution (12 mmol / L); Flow rate: 1.0 mL / min; Column temperature: 40°C; Column: IC-SA2 (250 L x 4.0) Note that, since the salt content does not change during the process of producing a resin sheet from the ionomer resin composition or ionomer resin, the calculated salt content of each ionomer resin composition or each ionomer resin corresponds to the salt content of the corresponding resin sheet.

[0130] [Flowability (Melt Flow Rate (MFR))] The MFR of the raw material resins used in the examples and comparative examples, and the ionomer resin compositions or ionomer resins obtained in the examples and comparative examples were measured in accordance with JIS K7210-1: 2014. Specifically, each resin composition or resin was melted in a cylinder and extruded at 190°C and a load of 2.16 kg through a die with a nominal hole diameter of 2.095 mm installed at the bottom of the cylinder, and the amount of resin composition or resin extruded per 10 minutes (g / 10 minutes) was measured.

[0131] [Thermal Decomposition Resistance] The thermal decomposition resistance of the ionomer resin compositions or ionomer resins 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 (Hitachi High-Tech Science Corporation), the weight loss rate was measured when each resin composition or resin 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.

[0132] [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.).

[0133] [Yellowness Index (YI) of Resin Sheet] For each of the resin sheets obtained in the examples and comparative examples, the yellowness index was measured in accordance with JIS Z8722:2009 using a colorimeter "ZE-2000" (manufactured by Nippon Denshoku Industries Co., Ltd.).

[0134] [Contact angle of resin sheet] Each resin sheet obtained in the examples and comparative examples was cut into a 50 mm square and subjected to corona treatment using a corona treatment machine (Kasuga Electric Co., Ltd., table-top treatment device (wire electrode) and high-frequency power supply AGF-B10S). In accordance with JIS K6768, the contact angle of distilled water was measured using a contact angle meter (Kyowa Interface Science Co., Ltd., DropMaster 500) in a standard room at a temperature of 23°C and a relative humidity of 50%. For comparative examples 1 and 2, the contact angle was measured without corona treatment.

[0135] [Transparency upon annealing (annealing haze)] Each resin sheet obtained in the examples and comparative examples was cut into a 100 mm square, sandwiched between two 100 mm square 2.7 mm thick float glass sheets, and placed in a vacuum laminator (Nisshinbo Mechatronics Inc., 1522N). The pressure inside the vacuum laminator was reduced at 100 ° C. for 1 minute, and the mixture was pressed 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 obtained laminated glass was heated to 140 ° C. and then annealed to 23 ° C. at a rate of 0.1 ° C. / min. The haze of the laminated glass after the annealing operation was measured in accordance with JIS K7136:2000 using a haze meter HZ-1 (manufactured by Suga Test Instruments Co., Ltd.).

[0136] [Adhesion to Glass] The resin sheets obtained in the Examples and Comparative Examples were sandwiched between two 2.7 mm thick float glass sheets and placed in a vacuum laminator (1522N manufactured by Nisshinbo Mechatronics Inc.). The pressure inside the vacuum laminator was reduced at 100°C for 1 minute, and the laminate was pressed at 30 kPa for 5 minutes while maintaining the reduced pressure and temperature to obtain a temporary bonded structure. The resulting temporary bonded structure was placed in an autoclave and treated at 140°C and 1.2 MPa for 30 minutes to obtain a laminated glass. The resulting laminated glass was then cut into a size of 25 mm x 25 mm to obtain a test sample. The resulting test sample was evaluated using the compressive shear strength test described in WO 1999 / 058334. The maximum shear stress at which the laminated glass peeled off was used as an index of adhesion to glass. When measuring the adhesion to the tin side of the glass, laminated glass was prepared so that the tin sides of two pieces of float glass were in contact with both sides of the resin sheet, and when measuring the adhesion to the air side of the glass, laminated glass was prepared so that the air sides of two pieces of float glass were in contact with both sides of the resin sheet.

[0137] [Raw Material Resin] In the Examples and Comparative Examples, the amount of methyl methacrylate (MMA) modification or the amount of ethyl acrylate (EA) modification, and 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.

[0138]

[0139] Example 1: 100 parts by mass of EMMA2 listed in Table 1 was placed in a stainless steel pressure vessel, and 233 parts by mass of toluene was added thereto. The mixture was stirred at 60°C under a pressure of 0.02 MPa to dissolve the EMMA2. 100 parts by mass of a 20% by mass solution of sodium hydroxide in methanol was added to the resulting solution, and the mixture was stirred at 100°C for 4 hours to saponify the EMMA2 and convert some of the methyl methacrylate units to sodium methacrylate units. The solution was then cooled to 50°C, 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 solution containing a crude ionomer resin. A mixed solvent of toluene / methanol (75 / 25% by mass) was added to the resulting solution to a crude ionomer resin concentration of 10% by mass, thereby diluting the solution. The resulting diluted solution containing the crude ionomer resin was then adjusted to 34°C, and 430 parts by weight of 34°C methanol was added to the diluted solution per 100 parts by weight of the crude ionomer resin solution to precipitate granules containing the crude ionomer resin. The resulting granules were then filtered, and 100 parts by weight of the filtered granules were mixed with 600 parts by weight of a water / methanol (50 / 50% by weight) mixed solvent. The resulting slurry was stirred at 40°C for 1 hour, and the granules were then filtered at room temperature. The granules were washed three more times with a water / methanol (50 / 50% by weight) mixed solvent and then vacuum dried for at least 8 hours. The resulting granular ionomer resin composition containing the ionomer resin and salt was analyzed, and its properties were evaluated. The analytical and evaluation results are shown in Table 2. Next, the obtained ionomer resin composition was melt-kneaded at 210°C, and the melt-kneaded product was heated at 210°C and subjected to a pressure of 4.9 MPa (50 kgf / cm ２ The resin sheet was compression molded at a pressure of 0.31 kW for 5 minutes to obtain a resin sheet having a thickness of 0.8 mm. Both surfaces of the obtained resin sheet were subjected to a corona treatment at an output of 0.31 kW and a feed rate of 7.9 m / s, and the contact angles on both surfaces of the resin sheet were measured. The contact angles were found to be identical. The contact angles are shown in Table 2. Subsequently, laminated glass was produced using the obtained resin sheet and evaluated. The evaluation results are shown in Table 2.

[0140] Example 2 An ionomer resin composition was obtained, analyzed, and evaluated in the same manner as in Example 1, except that EMMA3 was used instead of EMMA2, 95 parts by mass of nitric 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 37°C. A resin sheet was prepared in the same manner as in Example 1, except that the obtained ionomer resin composition was used. Corona treatment was performed in the same manner as in Example 1, and the contact angle was measured, except that the feed rate was changed to 2.6 m / s. Furthermore, laminated glass was prepared and evaluated in the same manner as in Example 1, except that the obtained resin sheet was used. The results are shown in Table 2.

[0141] Example 3 An ionomer resin composition was obtained, and analysis and evaluation were carried out 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 the methanol was changed from 34°C to 40°C. A resin sheet was produced in the same manner as in Example 1, except that the obtained ionomer resin composition was used, and a corona treatment was carried out in the same manner as in Example 1, except that the feed rate was changed to 1.3 m / s, and the contact angle was measured. Furthermore, laminated glass was produced and evaluated in the same manner as in Example 1, except that the obtained resin sheet was used. The results are shown in Table 2.

[0142] Example 4 An ionomer resin composition was obtained, analyzed, and evaluated in the same manner as in Example 1, except that EEA1 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 40°C. A resin sheet was prepared in the same manner as in Example 1, except that the obtained ionomer resin composition was used. Corona treatment was performed in the same manner as in Example 1, and the contact angle was measured in the same manner as in Example 1, except that the feed rate was changed to 2.6 m / s. Furthermore, laminated glass was prepared and evaluated in the same manner as in Example 1, except that the obtained resin sheet was used. The results are shown in Table 2.

[0143] Example 5 An ionomer resin composition was obtained, analyzed, and evaluated in the same manner as in Example 1, except that EMMA1 was used instead of EMMA2, the amounts of the methanol solution of sodium hydroxide (20% by mass) and hydrochloric acid (20% by mass) were changed to 80 parts by mass and 66 parts by mass, respectively, the concentration of the diluted solution containing the crude ionomer resin was changed from 10% by mass to 6% by mass, and the temperature of the diluted solution containing the crude ionomer resin and methanol was changed from 34°C to 41°C. A resin sheet was prepared, subjected to a corona treatment, and the contact angle was measured in the same manner as in Example 1, except that the obtained ionomer resin composition was used. Furthermore, a laminated glass was prepared and evaluated in the same manner as in Example 1, except that the obtained resin sheet was used. The results are shown in Table 2.

[0144] Example 6 An ionomer resin composition was obtained, and analysis and evaluation were carried out 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 the methanol was changed from 34°C to 41°C. A resin sheet was produced in the same manner as in Example 1, except that the obtained ionomer resin composition was used, and a corona treatment was carried out in the same manner as in Example 1, except that the feed rate was changed to 1.3 m / s, and the contact angle was measured. Furthermore, laminated glass was produced and evaluated in the same manner as in Example 1, except that the obtained resin sheet was used. The results are shown in Table 2.

[0145] Example 7 An ionomer resin composition was obtained, analyzed, and evaluated 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. A resin sheet was prepared in the same manner as in Example 1, except that the feed rate was changed to 1.3 m / s and the number of treatments was changed to two, and the corona treatment was performed in the same manner as in Example 1, and the contact angle was measured. Furthermore, a laminated glass was prepared and evaluated in the same manner as in Example 1, except that the resin sheet was used. The results are shown in Table 2.

[0146] Comparative Example 1 An ionomer resin composition was obtained, and analysis and evaluation were carried out in the same manner as in Example 1, except that EMMA1 was used instead of EMMA2, and the amounts of the methanol solution of sodium hydroxide (20% by mass) and hydrochloric acid (20% by mass) were changed to 80 parts by mass and 66 parts by mass, respectively. A resin sheet was produced in the same manner as in Example 1, except that the obtained ionomer resin composition was used, and the contact angle was measured without performing corona treatment. Furthermore, laminated glass was produced and evaluated in the same manner as in Example 1, except that the obtained resin sheet was used. The results are shown in Table 2.

[0147] Comparative Example 2 An ionomer resin composition was obtained, and analysis and evaluation were carried out 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 the methanol was changed from 34°C to 37°C. A resin sheet was produced in the same manner as in Example 1, except that the obtained ionomer resin composition was used, and the contact angle was measured without performing corona treatment. Furthermore, laminated glass was produced and evaluated in the same manner as in Example 1, except that the obtained resin sheet was used. The results are shown in Table 2.

[0148] Comparative Example 3 An ionomer resin composition was obtained, analyzed, and evaluated in the same manner as in Example 1, except that EMMA4 was used instead of EMMA2, the amounts of the methanol solution of sodium hydroxide (20% by mass) and hydrochloric acid (20% by mass) were changed to 72 parts by mass and 59 parts by mass, respectively, and the temperature of the diluted solution containing the crude ionomer resin and the methanol was changed from 34°C to 40°C. A resin sheet was prepared, subjected to a corona treatment, and the contact angle was measured in the same manner as in Example 1, except that the obtained ionomer resin composition was used. Furthermore, laminated glass was prepared and evaluated in the same manner as in Example 1, except that the obtained resin sheet was used. The results are shown in Table 2.

[0149] Comparative Example 4 An ionomer resin composition was obtained, analyzed, and evaluated in the same manner as in Example 1, except that EMMA3 was used instead of EMMA2, 95 parts by mass of nitric 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 40°C. A resin sheet was produced in the same manner as in Example 1, except that the obtained ionomer resin composition was used. Corona treatment was performed in the same manner as in Example 1, except that the feed speed was changed to 1.3 m / s and the number of treatments was changed to 10, and the contact angle was measured. Furthermore, laminated glass was produced and evaluated in the same manner as in Example 1, except that the obtained resin sheet was used. The results are shown in Table 2.

[0150] Comparative Example 5 An ionomer resin composition was obtained in the same manner as in Example 1, except that EMMA1 was used instead of EMMA2, and the amounts of the methanol solution of sodium hydroxide (20% by mass) and hydrochloric acid (20% by mass) were changed to 80 parts by mass and 66 parts by mass, respectively, and analysis and evaluation were performed. A resin sheet was produced in the same manner as in Example 1, except that the obtained ionomer resin composition was used. Corona treatment was performed in the same manner as in Example 1, except that the feed speed was changed to 1.3 m / s and the number of treatments was changed to 5, and the contact angle was measured. Furthermore, laminated glass was produced and evaluated in the same manner as in Example 1, except that the obtained resin sheet was used. The results are shown in Table 2.

[0151] Comparative Example 6 An ionomer resin composition was obtained, analyzed, and evaluated 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 43°C. A resin sheet was produced in the same manner as in Example 1, except that the obtained ionomer resin composition was used. Corona treatment was performed and the contact angle was measured in the same manner as in Example 1, except that the feed rate was changed to 1.3 m / s. Furthermore, laminated glass was produced and evaluated in the same manner as in Example 1, except that the obtained resin sheet was used. The results are shown in Table 2.

[0152] Comparative Example 7 An ionomer resin composition was obtained, analyzed, and evaluated in the same manner as in Example 1, except that EMMA3 was used instead of EMMA2, 95 parts by mass of nitric acid (30% by mass) was used instead of 83 parts by mass of hydrochloric acid (20% by mass), and the granules were washed six times with a water / methanol (50 / 50% by mass) mixed solvent. A resin sheet was produced in the same manner as in Example 1, except that the obtained ionomer resin composition was used. Corona treatment was performed and the contact angle was measured in the same manner as in Example 1, except that the feed speed was changed to 2.6 m / s. Furthermore, laminated glass was produced and evaluated in the same manner as in Example 1, except that the obtained resin sheet was used. The results are shown in Table 2. Note that "N.D." in Table 2 means that no salt was detected, and the salt content was less than 1 mg / kg.

[0153]

[0154] As shown in Table 2, the resin sheets obtained in Examples 1 to 7 were confirmed to have excellent adhesion to glass as well as excellent transparency. Furthermore, with regard to adhesion to glass, it was confirmed that the adhesion to not only the tin surface but also the air surface was excellent. In contrast, the resin sheets obtained in Comparative Examples 1 to 5 had poor adhesion to glass, particularly to the air surface, and the resin sheet obtained in Comparative Example 3 also had poor transparency upon slow cooling. The resin sheet obtained in Comparative Example 6 had poor transparency upon water absorption. The resin sheet obtained in Comparative Example 7 had poor thermal decomposition resistance and, despite having a contact angle that satisfied the specific range of the present invention, had poor adhesion to glass, particularly to the air surface.

[0155] The resin sheet of the present invention has the properties of high transparency and excellent adhesion to glass, and therefore can be suitably used as an interlayer film for laminated glass, for example, as an interlayer film for laminated glass for architectural and structural applications (e.g., building materials such as laminates for facades, exterior walls, or roofs, panels, doors, windows, walls, roofs, sunroofs, soundproof walls, display windows, balconies, and handrail walls, conference room partition glass components, solar panels, etc.), or as an interlayer film for laminated glass for vehicular applications (e.g., automobile windshields, automobile side glass, automobile sunroofs, automobile rear glass, glass for head-up displays, etc.). Furthermore, the laminated glass of the present invention can be suitably used as laminated glass for architectural and structural applications or vehicular applications.

Claims

1. A resin sheet having at least one layer comprising an ionomer resin composition, wherein the layer comprising the ionomer resin composition forms at least one surface of the resin sheet, the contact angle measured in accordance with JIS K6768 of the surface is 60 to 75 degrees, the ionomer resin composition comprises an ionomer resin containing (meth)acrylic acid units (A), (meth)acrylic acid neutralized units (B), and ethylene units (C), and a salt composed of a strong acid and a strong base, 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 content of the salt is 1 to 400 mg / kg based on the total mass of the ionomer resin composition, the resin sheet.

2. the layer comprising the ionomer resin composition forms both surfaces of the resin sheet, the contact angle measured in accordance with JIS K6768 of both surfaces is 60 to 75 degrees, The resin sheet according to claim 1.

3. 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 resin sheet according to claim 1.

4. The salt is a metal salt of an alkali metal and / or an alkaline earth metal, the resin sheet according to claim 1.

5. The salt 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 resin sheet according to claim 1.

6. An insulating glass interlayer comprising the resin sheet according to any one of claims 1 to 5.

7. An insulating glass having two glass plates and the insulating glass interlayer according to claim 6 disposed between the two glass plates.