Ionomer resin, resin sheet, and laminated glass

Abstract

The present invention relates to an ionomer resin comprising: a (meth) acrylic acid unit (A), a (meth) acrylic acid neutralization unit (B), and an ethylene unit (C), the total content of the unit (A) and the unit (B) being 6 to 10 mol% based on the total monomer units constituting the aforementioned ionomer resin, and the content of a transition metal in the aforementioned ionomer resin being 0.01 to 100 mg / kg.

Description

TECHNICAL FIELD

[0001] This patent application claims priority under the Paris Convention to Japanese Patent Application No. 2020-163733 (Filing Date: September 29, 2020), which is hereby incorporated by reference in its entirety into the present specification.

[0002] The present application relates to an ionomer resin and a method for producing the same, a resin sheet having one or more layers containing the ionomer resin, a laminated glass interlayer film containing the resin sheet, and a laminated glass having the laminated glass interlayer film. BACKGROUND

[0003] An ionomer, which is a neutralized product of an ethylene-unsaturated carboxylic acid copolymer, is excellent in transparency and adhesion to glass, and thus is used for an interlayer film of a laminated glass (for example, Patent Literature 1). In recent years, the required performance of a laminated glass has become higher, and for an ionomer resin, it is also increasingly required to maintain high transparency regardless of the production conditions of a laminated glass, to maintain a high elastic modulus at a high temperature without reducing the strength of a laminated glass, to be less colored and excellent in appearance, to be excellent in adhesion to glass and not easily peeled from glass, and the like.

[0004] Patent Literature 2 describes a polymer sheet having at least one layer containing an ionomer or an ionomer mixture into which an α,β-ethylenically unsaturated carboxylic acid is introduced, the ionomer or the ionomer mixture containing ions of one or more monovalent metals in an amount ranging from about 1 to about 60% and ions of one or more polyvalent metals in an amount ranging from about 40 to about 99%, based on the total amount of neutralization of the α,β-ethylenically unsaturated carboxylic acid.

[0005] Patent Literature 3 describes a resin composition containing an ionomer resin and an adhesion promoter, the adhesion promoter being a dialkoxy silane compound.

[0006] Prior Art Documents

[0007] Patent Literature

[0008] Patent Literature 1: U.S. Patent No. 6432522

[0009] Patent Literature 2: Japanese Patent Application Laid-Open No. 2009-512763

[0010] Patent Literature 3: International Publication No. 2019 / 027865 SUMMARY

[0011] PROBLEMS TO BE SOLVED BY THE INVENTION

[0012] When a laminated glass is used outdoors, delamination occurs between the glass and the interlayer film of the laminated glass, or whitening occurs to cause a reduction in transparency, particularly at the end portions of the laminated glass, due to moisture such as rain. Therefore, there is a demand for ionomer resins that can form laminated glass interlayer films having high transparency and adhesion to glass even under high humidity conditions.

[0013] It is described in Patent Literature 2 that the ionomer or ionomer mixture described in this document exhibits improved glass adhesion synergistically. However, according to the research by the present inventors and others, the ionomer described in Patent Literature 2 not only whitens to easily cause a reduction in transparency under high humidity conditions, but also easily causes delamination from glass, and the adhesion to glass is not necessarily sufficient.

[0014] It is described in Patent Literature 3 that the resin composition described in this document exhibits high adhesion to glass even under high humidity conditions. However, according to the research by the present inventors and others, the resin composition described in Patent Literature 3 easily produces crosslinked gels at the time of molding processing, and further improvement is required in order to obtain a resin sheet having a good appearance.

[0015] Therefore, the object of the present application is to provide an ionomer resin having high transparency and high adhesion to a substrate such as glass even under high humidity conditions, and capable of forming a sheet having a good appearance, and a method for producing the same.

[0016] Solution to the problem

[0017] The present inventors and others have conducted intensive research in order to solve the above problem, and as a result, the present application has been achieved. That is, the present application provides the following suitable solutions.

[0018] 〔1〕 An ionomer resin comprising: a (meth)acrylic acid unit (A),

[0019] a (meth)acrylic acid neutralization product unit (B), and

[0020] an ethylene unit (C),

[0021] the total content of the units (A) and (B) being 6 to 10 mol% based on the total monomer units constituting the ionomer resin,

[0022] the content of the transition metal in the ionomer resin being 0.01 to 100 mg / kg.

[0023] 〔2〕 The ionomer resin according to (1), wherein the ionomer resin further comprises a (meth)acrylic acid ester unit (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.

[0024] 〔3〕 The ionomer resin according to any one of 〔1〕 to 〔2〕, wherein the transition metal is one or more metals selected from the group consisting of iron, nickel, manganese, and chromium.

[0025] 〔4〕 A resin sheet having one or more layers comprising the ionomer resin according to any one of 〔1〕 to 〔3〕.

[0026] 〔5〕 A laminated glass interlayer film comprising the resin sheet according to 〔4〕.

[0027] 〔6〕 A laminated glass having: two glass sheets; and the laminated glass interlayer film according to 〔5〕 disposed between the two glass sheets.

[0028] 〔7〕 A method for producing the ionomer resin according to any one of 〔1〕 to 〔3〕, comprising: a step of saponifying an ethylene-(meth)acrylate copolymer with a strong base, and

[0029] a step of demetallizing the saponate obtained by the aforementioned step with a strong acid,

[0030] the aforementioned saponification step and / or the aforementioned demetallization step are performed in the presence of a transition metal.

[0031] 〔8〕 The method according to 〔7〕, wherein the aforementioned demetallization is performed by adding the strong acid to a solution of the saponate.

[0032] 〔9〕 The method according to 〔7〕 or 〔8〕, wherein the aforementioned saponification step and / or the aforementioned demetallization step are performed using a reaction apparatus, at least a part of the aforementioned reaction apparatus being an alloy comprising 50 mass% or more of nickel and chromium in total as transition metals.

[0033] 〔10〕 The method according to 〔9〕, wherein at least a part of the aforementioned reaction apparatus is at least a part selected from the group consisting of a reaction tank, a stirring blade, a baffle, and a feed line for supplying the strong base and / or the strong acid into the reaction tank.

[0034] Effects of the Invention

[0035] According to the present application, it is possible to provide an ionomer resin having high transparency and high adhesion to glass even under high humidity conditions, and a manufacturing method thereof, and a resin sheet having a good appearance. DETAILED DESCRIPTION

[0036] Hereinafter, the embodiments of the present application will be described in detail. It should be noted that the scope of the present application is not limited to the embodiments described hereinafter, and various modifications can be made without departing from the spirit of the present application.

[0037] 〔ionomer resin〕

[0038] The ionomer resin of the present application contains: a (meth)acrylic acid unit (A), a (meth)acrylic acid neutralization unit (B), and an ethylene unit (C), and the content of a transition metal in the ionomer resin is 0.01 to 100 mg / kg.

[0039] The ionomer resin of the present application contains a transition metal, and the content thereof is 0.01 to 100 mg / kg. The present inventors have found that, if the ionomer resin contains a transition metal in an amount of 0.01 to 100 mg / kg, the transparency of the ionomer resin, particularly the transparency under high humidity conditions (e.g., the whitening resistance under high humidity conditions), can be maintained, and unexpectedly, the adhesion to glass, particularly the adhesion to glass under high humidity conditions, is improved. Thus, the ionomer resin of the present application has high transparency and high adhesion to glass even under high humidity conditions. The reason why the transparency of the ionomer resin under high humidity conditions and the adhesion to glass are improved by setting the content of the transition metal in the ionomer resin to 0.01 to 100 mg / kg is not clear, but it is considered that this is because of the interaction of the transition metal with the (meth)acrylic acid unit (A) in the ionomer resin; and / or, the water absorption of the ionomer resin is suppressed as compared with an ionomer resin not containing a transition metal.

[0040] Further, the present inventors have also found that the ionomer resin of the present application, even if it has high adhesion to glass (particularly under high humidity conditions), is unexpectedly less likely to generate crosslinked gels, and as a result, a resin sheet having a good appearance is easily obtained. Generally, a resin having improved adhesion to glass tends to generate crosslinked gels and is less likely to obtain a resin sheet having a good appearance, but the ionomer resin of the present application unexpectedly has high adhesion to glass, and further, a resin sheet having a good appearance is easily obtained.

[0041] In addition, the present inventors have also found that, by setting the content of the transition metal in the ionomer resin to 0.01 to 100 mg / kg, the heat decomposition resistance of the ionomer resin is also improved. The reason why the ionomer resin of the present application has excellent heat decomposition resistance is not clear, but it is considered that this is because the (meth)acrylic acid unit (A) in the ionomer resin is easily suppressed from being removed by heat by the interaction of the transition metal with the (meth)acrylic acid unit (A) in the ionomer resin.

[0042] On the other hand, if the content of the transition metal in the ionomer resin is outside the above range, the transparency of the ionomer resin (particularly, the transparency under high humidity conditions), the adhesion to glass (particularly, the adhesion to glass under high humidity conditions), and the heat decomposition resistance of the ionomer resin tend to decrease. If the content of the transition metal is less than 0.01 mg / kg, the adhesion to glass under high humidity conditions tends to decrease, and thus peeling between the glass and the ionomer resin is likely to occur under high humidity conditions, for example, in the case where a resin sheet containing the ionomer resin is used as an interlayer film of laminated glass outdoors, particularly, at the end portion of the laminated glass, peeling between the glass and the interlayer film of the laminated glass is likely to occur. In addition, if the content of the transition metal exceeds 100 mg / kg, the transparency of the ionomer resin, particularly, the transparency under high humidity conditions is likely to decrease, for example, in the case where a resin sheet containing the ionomer resin is used as an interlayer film of laminated glass outdoors, particularly, at the end portion of the laminated glass, whitening is likely to occur. In addition, if the content of the transition metal exceeds 100 mg / kg, the ionomer resin is likely to be colored, and the yellowness YI is likely to increase at the time of molding.

[0043] The content of the aforementioned transition metal is preferably 0.01 mg / kg or more, more preferably 0.05 mg / kg or more, further preferably 0.1 mg / kg or more, and particularly preferably 0.2 mg / kg or more, from the viewpoint of easily improving the transparency, the adhesion to glass under high humidity conditions, and the heat decomposition resistance. In addition, the content of the aforementioned transition metal is preferably 100 mg / kg or less, more preferably 50 mg / kg or less, further preferably 20 mg / kg or less, and particularly preferably 10 mg / kg or less, from the viewpoint of easily improving the transparency and the heat decomposition resistance, and the viewpoint of easily suppressing the coloring of the ionomer resin. The content of the transition metal in the ionomer resin can be adjusted by the method of producing the ionomer resin. The content of the transition metal in the ionomer resin can be measured using inductively coupled plasma (ICP) emission spectroscopy, for example, by the method described in the examples.

[0044] The transition metal contained in the ionomer resin is not particularly limited, and examples thereof include first transition metals such as scandium, titanium, vanadium, chromium, manganese, iron, cobalt, and nickel, and second transition metals such as yttrium, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, and silver. These transition metals can be one kind alone, or two or more kinds in combination.

[0045] In one embodiment of the present application, the aforementioned transition metal is preferably a first transition metal, more preferably one or more metals selected from the group consisting of iron, nickel, manganese, and chromium, and particularly preferably one or more metals containing at least iron, from the viewpoint of easily improving the transparency of the ionomer resin under high humidity conditions, the heat decomposition resistance, and the adhesion to glass under high humidity conditions.

[0046] In the present application, the state of the transition metal contained in the ionomer resin is not particularly limited. The transition metal can be contained in the ionomer resin in the form of, for example, a transition metal oxide, a transition metal hydroxide, a transition metal halide, a transition metal salt, or the like, or can be contained in the form of a metal ion in the (meth)acrylic acid neutralizer unit (B) in the ionomer resin.

[0047] The ionomer resin of the present application contains: a (meth)acrylic acid unit (A), a (meth)acrylic acid neutralizer unit (B), and an ethylene unit (C), and the total content of the aforementioned unit (A) and the aforementioned unit (B) is 6 to 10 mol% based on the total monomer units constituting the aforementioned ionomer resin.

[0048] In the present application, "unit" means a "structural unit of origin", for example, the (meth)acrylic acid unit means a structural unit of origin of (meth)acrylic acid, the (meth)acrylic acid neutralizer unit means a structural unit of origin of (meth)acrylic acid neutralizer, and the ethylene unit means a structural unit of origin of ethylene. In addition, in the present specification, "(meth)acrylic acid" means methacrylic acid or acrylic acid.

[0049] When the aforementioned total content is 6 to 10 mol% based on the total monomer units constituting the ionomer resin, the transparency and the modulus of elasticity (for example, the modulus of elasticity at 50°C) of the ionomer resin are easily improved. On the other hand, when the aforementioned total content exceeds the upper limit value, the ionomer resin does not easily exhibit a high modulus of elasticity (for example, the modulus of elasticity at 50°C). In addition, when the aforementioned total content is lower than the lower limit value, the ionomer resin has a tendency to easily undergo whitening when the crystallinity is too high, and thus the transparency in a state in which the ionomer resin is slowly cooled so that the crystallization of the resin is promoted (transparency upon slow cooling) easily decreases, for example, in the case where the ionomer resin is slowly cooled after being processed at a high temperature when making laminated glass.

[0050] With respect to the aforementioned total content, from the viewpoint of easily improving the transparency (particularly, the transparency upon slow cooling) of the ionomer resin and the adhesion to glass, it is 6 mol% or more, preferably 6.5 mol% or more, more preferably 7.0 mol% or more, and further preferably 7.5 mol% or more, and from the viewpoint of easily improving the modulus of elasticity of the ionomer resin and the moldability, it is 10 mol% or less, preferably 9.9 mol% or less, and more preferably 9.5 mol% or less.

[0051] The total content of the aforementioned unit (A) and the aforementioned unit (B) can be adjusted depending on the method of manufacturing the ionomer resin. More specifically, in the case where the ionomer resin is manufactured by a method including a saponification reaction step and a demetallization reaction step using an ethylene-(meth)acrylate copolymer as a raw material, the content can be adjusted depending on the reaction rate (conversion ratio) of the conversion of the (meth)acrylate unit in the ethylene-(meth)acrylate copolymer into the (meth)acrylic acid unit (A) and the (meth)acrylic acid neutralization product unit (B) by the aforementioned saponification reaction and demetallization reaction. In addition, in the case where the ionomer resin is manufactured by polymerizing ethylene and (meth)acrylic acid using them as raw materials as described in U.S. Patent No. 8399096, the content can be adjusted by the ratio of ethylene to (meth)acrylic acid that is copolymerized.

[0052] As examples of the monomer constituting the (meth)acrylic acid unit (A), acrylic acid and methacrylic acid can be given, and methacrylic acid is preferred from the viewpoints of heat resistance and adhesion to a substrate such as glass. These (meth)acrylic acid units can be one alone or two or more in combination.

[0053] As for the content of the (meth)acrylic acid unit (A) in the ionomer resin, there is no particular limitation as long as the total content of the aforementioned unit (A) and the aforementioned unit (B) is in the range of 6 to 10 mol% based on the total monomer units constituting the ionomer resin. In one embodiment of the present application, 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, further preferably 5.5 mol% or more, particularly preferably 5.8 mol% or more, and, in addition, is preferably 9.0 mol% or less, more preferably 8.5 mol% or less, further preferably 8.0 mol% or less, particularly preferably 7.5 mol% or less, based on the total monomer units constituting the ionomer resin. If the aforementioned content of the unit (A) is the above lower limit value or more, the transparency and adhesion to a substrate such as glass of the ionomer resin are easily improved. In addition, if it is the above upper limit value or less, the moldability is easily improved.

[0054] The (meth)acrylic acid neutralization product is obtained by substituting a hydrogen ion of (meth)acrylic acid with a metal ion. As the (meth)acrylic acid neutralization product unit (B), the neutralization unit of the aforementioned (meth)acrylic acid unit (A) is preferred. As examples of the aforementioned metal ion, alkali metal ions such as lithium, sodium, and potassium; alkaline earth metal ions such as magnesium and calcium; non-transition metal ions of Groups 12 to 13 such as zinc and aluminum; and transition metal ions can be given. As the transition metal ion, the ion of the transition metal that can be contained in the aforementioned ionomer resin can be given. Such a metal ion can be one alone or two or more in combination.

[0055] The content of the (meth)acrylic acid neutralization unit (B) in the ionomer resin is not particularly limited as long as the total content of the unit (A) and the unit (B) is in the range of 6 to 10 mol% based on the total monomer units constituting the ionomer resin. In one embodiment of the present application, the content of the (meth)acrylic acid neutralization unit (B) is preferably 0.65 mol% or more, more preferably 1.0 mol% or more, further preferably 1.5 mol% or more, particularly preferably 1.7 mol% or more, and is preferably 3.0 mol% or less, more preferably 2.7 mol% or less, further preferably 2.6 mol% or less, particularly preferably 2.5 mol% or less, based on the total monomer units constituting the ionomer resin. If the content of the unit (B) is the above lower limit value or more, the transparency and the elastic modulus are easily improved, and if the content of the unit (B) is the above upper limit value or less, the increase in the melt viscosity at the time of molding is easily suppressed.

[0056] In the case where the ionomer resin is produced by a method including a saponification reaction step and a demetallization reaction step using an ethylene-(meth)acrylic ester copolymer as a raw material, the respective contents of the unit (A) and the unit (B) can be adjusted according to the reaction rates of the respective reactions in which the (meth)acrylic ester unit in the ethylene-(meth)acrylic ester copolymer is converted into the (meth)acrylic acid unit (A) and the (meth)acrylic acid neutralization unit (B) by the saponification reaction and the demetallization reaction.

[0057] <Ethylene unit (C)>

[0058] The content of the ethylene unit (C) is preferably 80 mol% or more, more preferably 85 mol% or more, further preferably 88 mol% or more, based on the total monomer units constituting the ionomer resin, from the viewpoint of easily improving the impact resistance of the ionomer resin, and is preferably 94 mol% or less, more preferably 91 mol% or less, from the viewpoint of easily improving the transparency of the ionomer resin (particularly the transparency at the time of slow cooling). If the content of the ethylene unit (C) is the above lower limit value or more, the mechanical strength and the moldability are easily improved, and if the content of the ethylene unit (C) is the above upper limit value or less, the ionomer resin becomes less likely to be crystallized, and the transparency (particularly the transparency at the time of slow cooling) is easily improved.

[0059] The ionomer resin of the present application preferably further contains a (meth)acrylic ester unit (D) in addition to the (meth)acrylic acid unit (A), the (meth)acrylic acid neutralization unit (B), and the ethylene unit (C), from the viewpoint of easily obtaining higher transparency.

[0060] When the ionomer resin contains (meth)acrylate units (D), the total content of the units (A), (B), and (D) is preferably 6 to 10 mol% based on all monomer units constituting the ionomer resin from the viewpoint of easily improving transparency (particularly transparency during slow cooling). That is, in a preferred embodiment of the present invention, the ionomer resin of the present invention contains (meth)acrylic acid units (A), neutralized (meth)acrylic acid units (B), ethylene units (C), and (meth)acrylate 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)acrylate units (D), when the total content of the units (A), (B), and (D) is below the upper limit, the ionomer resin tends to exhibit a high elastic modulus. On the other hand, when the total content is above the lower limit, the transparency of the ionomer resin, particularly transparency during slow cooling, tends to be improved.

[0061] When the ionomer resin contains (meth)acrylate units (D), the total content of the units (A), (B), and (D) is 6 mol% or more, preferably 6.5 mol% or more, more preferably 7.0 mol% or more, and even more preferably 7.5 mol% or more, from the viewpoint of easily improving transparency (particularly transparency during slow cooling) and adhesion to substrates such as glass. Furthermore, from the viewpoint of easily improving the elastic modulus and moldability of the ionomer resin, the total content is 10 mol% or less, preferably 9.9 mol% or less, and more preferably 9.5 mol% or less.

[0062] The total content of the aforementioned units (A), (B), and (D) can be adjusted depending on the raw materials of the ionomer resin. More specifically, when the ionomer resin is produced by a method comprising a saponification reaction step and a demetallization reaction step using an ethylene-(meth)acrylate copolymer as a raw material, the total content can be adjusted depending on the (meth)acrylate modification amount of the ethylene-(meth)acrylate copolymer serving as the raw material of the ionomer resin. Furthermore, as described in U.S. Patent No. 8,399,096, when the ionomer resin is produced by polymerizing ethylene and (meth)acrylic acid as raw materials, the total content can be adjusted depending on the ratio of the copolymerized ethylene to (meth)acrylic acid.

[0063] (As examples of the monomer constituting the (meth)acrylate unit (D), mention can be made of 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, allyl (meth)acrylate, and the like.

[0064] Among these, from the viewpoints of transparency or heat resistance, the preferable monomer is 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 the more preferable monomer is methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, and the further preferable monomer is methyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, and the particularly preferable monomer is methyl (meth)acrylate. These (meth)acrylates can be one alone or a combination of two or more.

[0065] In the case where the ionomer resin contains the (meth)acrylate unit (D), the content of the (meth)acrylate unit (D) in the ionomer resin is not particularly limited. In one embodiment of the present application, the content of the (meth)acrylate unit (D) in the ionomer resin is more preferably 0.01 mol% or more, further preferably 0.05 mol% or more, particularly preferably 0.08 mol% or more, based on the total monomer units constituting the ionomer resin, and is preferably 1.0 mol% or less, more preferably 0.7 mol% or less, further preferably 0.5 mol% or less. If the content of the unit (D) is within the above lower limit and the above upper limit, the transparency of the ionomer resin is easily improved.

[0066] As for the content of the aforementioned unit (D) when the ionomer resin contains the (meth)acrylate unit (D), in the case where the ionomer resin is produced by a method including a saponification reaction process and a demetallization reaction process using an ethylene-(meth)acrylate copolymer as a raw material, it can be adjusted according to the degree of reaction of the aforementioned saponification reaction in which the (meth)acrylate unit (D) in the ethylene-(meth)acrylate copolymer is converted into the (meth)acrylic acid unit (A).

[0067] The ionomer resin of the present application can contain, in addition to the (meth)acrylic acid unit (A), the (meth)acrylic acid neutralization unit (B), and the ethylene unit (C), and the (meth)acrylate unit (D) as the case can be, other monomer units. As examples of the other monomer units, there can be mentioned, in addition to the (meth)acrylic acid unit (A), a carboxylic acid unit (A1), a carboxylic acid neutralization unit (B1), and the like.

[0068] As examples of the monomer constituting the aforementioned carboxylic acid unit (A1), there can be mentioned itaconic acid, maleic anhydride, monomethyl maleate, monoethyl maleate, and the like, with monomethyl maleate and monoethyl maleate being preferred. As examples of the monomer constituting the aforementioned carboxylic acid neutralization unit (B1), there can be mentioned neutralization units of the aforementioned carboxylic acid unit (A1), and the like. Note that the carboxylic acid neutralization is obtained by replacing the hydrogen ion of the carboxylic acid with a metal ion. As the aforementioned metal ion, there can be mentioned the same as in the (meth)acrylic acid neutralization unit (B) described above, and the metal ion can be one kind alone or a combination of two or more kinds.

[0069] These other monomer units can be one kind alone or a combination of two or more kinds.

[0070] In the case where the ionomer resin contains the aforementioned other monomer units, the total content thereof, for example, the total content of (A1) and (B1), can be appropriately selected within a range not impairing the effects of the present application, for example, preferably 5 mol% or less, more preferably 3 mol% or less, further preferably 1 mol% or less, based on the total monomer units constituting the ionomer resin, and in addition, preferably 0.01 mol% or more, more preferably 0.1 mol% or more.

[0071] The respective contents of the (meth)acrylic acid unit (A), the (meth)acrylic acid neutralization unit (B), and the ethylene unit (C), and the (meth)acrylic ester unit (D) and other monomer units (e.g., unit (A1) and unit (B1)) in the ionomer resin of the present application can be determined as follows: first, the monomer units in the ionomer resin are identified by thermal decomposition gas chromatography, and then, nuclear magnetic resonance spectroscopy (NMR) and elemental analysis are used. More specifically, they can be determined by the methods described in the examples. Alternatively, they can be determined by a method combining the above analysis 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.

[0072] In one embodiment of the present application, the branching degree per 1000 carbons of the ionomer resin of the present application is not particularly limited, and is preferably 5 to 30, more preferably 6 to 20. For the aforementioned branching degree, for example, in the case where the ionomer resin is produced by a method including a saponification reaction step and a demetallization reaction step using an ethylene-(meth)acrylic ester copolymer as a raw material, it can be adjusted by the polymerization temperature at the time of synthesizing the ethylene-(meth)acrylic ester as a raw material. The branching degree per 1000 carbons can be determined by solid NMR with a wideband dipole decoupling / magic angle spinning (DD / MAS) method.

[0073] In one embodiment of the present application, the melting point of the ionomer resin of the present application is preferably 50°C or higher, more preferably 60°C or higher, further preferably 80°C or higher, from the viewpoint of heat resistance and heat decomposition resistance, and is preferably 200°C or lower, more preferably 180°C or lower, further preferably 150°C or lower, from the viewpoint of easily achieving adhesion to glass when producing laminated glass. The aforementioned melting point can be determined based on JIS K7121:2012. Specifically, it can be determined by a differential scanning calorimeter (DSC) under conditions of a cooling rate of -10°C / min and a temperature increase rate of 10°C / min, and can be determined from the peak top temperature of the melting peak at the second temperature increase.

[0074] In one embodiment of the present application, the heat of fusion of the ionomer resin of the present application is preferably 0 J / g or higher and 25 J / g or lower. The aforementioned heat of fusion can be determined based on JIS K7122:2012. Specifically, it can be determined by a differential scanning calorimeter (DSC) under conditions of a cooling rate of -10°C / min and a temperature increase rate of 10°C / min, and can be calculated from the area of the melting peak at the second temperature increase.

[0075] In one embodiment of the present application, the melt flow rate (MFR) of the ionomer resin of the present application measured according to JIS K7210 at 190°C under a load of 2.16 Kg is preferably 0.1 g / 10 minutes or more, more preferably 0.3 g / 10 minutes or more, further preferably 0.7 g / 10 minutes or more, further more preferably 1.0 g / 10 minutes or more, particularly preferably 1.5 g / 10 minutes or more, and is preferably 50 g / 10 minutes or less, more preferably 30 g / 10 minutes or less, particularly preferably 10 g / 10 minutes or less. If the MFR of the ionomer resin is within the above range, deterioration due to heat is suppressed, and molding is easily performed, and a resin sheet excellent in penetration resistance is easily obtained.

[0076] The melting point, heat of fusion, and MFR of the ionomer resin can be adjusted depending on the molecular weight of the ionomer resin, and the contents of the (meth)acrylic acid unit (A), the (meth)acrylic acid neutralization product unit (B), and the ethylene unit (C), and the (meth)acrylate unit (D) which can be contained as appropriate.

[0077] In one embodiment of the present application, the storage modulus (E') at 50°C of the ionomer resin of the present application measured by dynamic viscoelasticity measurement is preferably 20 MPa or more, more preferably 30 MPa or more, further preferably 40 MPa or more, particularly preferably 50 MPa or more, from the viewpoint of good self-standing property (i.e., high elastic modulus), particularly self-standing property 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 can be 1000 MPa. The aforementioned storage modulus can be adjusted depending on the molecular weight of the ionomer resin, and the contents of the (meth)acrylic acid unit (A), the (meth)acrylic acid neutralization product unit (B), and the ethylene unit (C), and the (meth)acrylate unit (D) which can be contained as appropriate. Note that the storage modulus (E') at 50°C of the ionomer resin can be measured by dynamic viscoelasticity measurement.

[0078] The ionomer resin of the present application contains the transition metal at 0.01 to 100 mg / kg as described above, and thus has high thermal decomposition resistance. In a suitable embodiment of the present application, the ionomer resin of the present application has a 1% weight reduction temperature (Td1) of 330°C or higher, more preferably 350°C or higher, further preferably 360°C or higher, particularly preferably 370°C or higher, and generally 450°C or lower, when the temperature is increased at 10°C / minute under a nitrogen atmosphere. If the 1% weight reduction temperature of the ionomer resin is higher than the above lower limit, foaming and / or thermal decomposition of the ionomer resin during melt molding and the like is easily reduced, and an interlayer film having no defects such as black foreign matter due to foaming and / or thermal decomposition of the resin is easily obtained. Note that, in the present specification, the 1% weight reduction temperature refers to the temperature at which the weight reduction rate becomes 1% with respect to the weight at 200°C. The aforementioned 1% weight reduction temperature can be measured in accordance with JIS K7120-1987, and for example, can be measured by the method described in the examples.

[0079] The ionomer resin of the present application has high transparency, and in a suitable embodiment of the present application, the ionomer resin of the present application has a haze of 2.0% or lower, more preferably 1.5% or lower, further preferably 1.0% or lower, at a sheet thickness of 0.8 mm. The smaller the haze, the higher the transparency of the ionomer resin, and thus the lower limit is not particularly limited, and for example, can be 0.01%. Note that the haze of the ionomer resin is measured with a haze meter in accordance with JIS K7136:2000.

[0080] The ionomer resin of the present application has high transparency even under high humidity conditions because the content of the transition metal is 0.01 to 100 mg / kg. The transparency of the ionomer resin under high humidity conditions can be evaluated by the haze of the ionomer resin in a state of having absorbed water (water absorption haze). In a suitable embodiment of the present application, the ionomer resin of the present application has a haze (water absorption haze) of 9.0% or lower, more preferably 5.0% or lower, further preferably 3.0% or lower, at a sheet thickness of 0.8 mm in a state of having absorbed water. The smaller the water absorption haze, the higher the transparency of the ionomer resin in a state of having absorbed water, and thus the lower limit is not particularly limited, and for example, can be 0.01%. Note that the water absorption haze can be measured as follows: the ionomer resin is left to stand in ion exchange water at 23°C for 300 hours, taken out from the ion exchange water, and the ionomer resin from which the water adhering to the surface is wiped off is used as a test piece, and the haze is measured with a haze meter in accordance with JIS K7136:2000, and for example, can be measured by the method described in the examples.

[0081] The ionomer resin of the present application has a high transparency even when slowly cooled because the total content of the (meth)acrylic acid unit (A) and the (meth)acrylic acid neutralization unit (B) in the resin is 6 mol% or more. In a suitable embodiment of the present application, the haze of the ionomer resin of the present application in a state in which crystallization of the resin is promoted by slow cooling (slowly cooled haze) is preferably 5.0% or less, more preferably 4.5% or less, further preferably 4.0% or less, further more preferably 3.0% or less, particularly preferably 2.5% or less. The smaller the haze, the higher the transparency of the ionomer resin, and therefore, the lower limit is not particularly limited, and for example, can be 0.01%. The slowly cooled haze can be obtained by preparing a laminated glass by disposing an ionomer resin having a sheet thickness of 0.8 mm between two glass plates, heating the laminated glass to 140°C, and measuring the haze after slowly cooling from 140°C to 23°C at a rate of 0.1°C / min, according to JIS K7136:2000 using a haze meter.

[0082] The ionomer resin of the present application has a low colorability because the content of the transition metal in the resin is 100 mg / kg or less, and therefore, coloring is less likely to occur even when molded. The yellow index (YI) of the ionomer resin of the present application when the sheet thickness is 0.8 mm is preferably 3.0 or less, more preferably 2.0 or less, further preferably 1.5 or less, particularly preferably 1.0 or less, from the viewpoint of being less likely to color. The smaller the yellow index (YI), the smaller the colorability of the ionomer resin, and therefore, the lower limit is not particularly limited, and for example, can be 0. It should be noted that the yellow index (YI) can be measured using a color difference meter according to JIS Z8722, and for example, can be measured by the method described in the examples.

[0083] The adhesion to glass of the ionomer resin of the present application can be evaluated based on the peel energy of the glass and the ionomer resin measured by a peel test. The peel energy of the glass and the ionomer resin measured under standard conditions (23°C, 50% RH) is preferably 2 kJ / m 2 or more, more preferably 2.5 kJ / m 2 or more, further preferably 3 kJ / m 2 or more, particularly preferably 3.5 kJ / m 2 or more. In addition, the adhesion to glass under high humidity conditions can be evaluated based on the peel energy of the glass and the ionomer resin measured by a peel test under high humidity conditions. The peel energy of the glass and the ionomer resin measured under high humidity conditions is preferably 0.05 kJ / m 2 or more, more preferably 0.1 kJ / m 2 or more, further preferably 0.15 kJ / m 2 or more, particularly preferably 0.2 kJ / m2 The upper limit of the aforementioned peel energy under the standard conditions and under the high humidity conditions is not particularly limited and can be 10 kJ / m 2 The aforementioned peel test can be performed, for example, by the method described as Peel Adhesion Measurement in International Publication No. 2019 / 027865. The peel energy measured under the standard conditions and under the wet conditions can be measured, for example, by the method described in the examples.

[0084] The ionomer resin of the present application can be produced, for example, by using ethylene-(meth)acrylate copolymer (X) as a raw material, by the following method (hereinafter also referred to as production method (I)) which comprises:

[0085] a step of saponifying ethylene-(meth)acrylate copolymer (X) with a strong base (saponification step), and

[0086] a step of demetallizing the saponate obtained by the aforementioned step with a strong acid (demetallization step),

[0087] The aforementioned saponification step and / or the aforementioned demetallization step are performed in the presence of a transition metal.

[0088] In the aforementioned production method (I), all or a part of the (meth)acrylate unit in ethylene-(meth)acrylate copolymer (X) is converted into a (meth)acrylic acid unit and a (meth)acrylic acid salt unit, whereby an ionomer resin comprising a (meth)acrylic acid unit (A), a (meth)acrylic acid salt unit (B), an ethylene unit (C), and, as the case can be, a (meth)acrylate unit (D) is obtained.

[0089] The aforementioned production method (I) can be a method (hereinafter also referred to as method (1)) in which all or a part of the (meth)acrylate unit in ethylene-(meth)acrylate copolymer is converted into a (meth)acrylic acid unit and a (meth)acrylic acid salt unit by the aforementioned saponification step and demetallization step, or can be a method (hereinafter also referred to as method (2)) in which all or a part of the (meth)acrylate unit in ethylene-(meth)acrylate copolymer is converted into a (meth)acrylic acid unit and a (meth)acrylic acid salt unit by a method which further comprises a neutralization step of neutralizing the demetallate obtained after the aforementioned saponification step and demetallization step.

[0090] In the aforementioned method (1), specifically, an ethylene-(meth)acrylate copolymer is saponified using a strong base, whereby all or a part of the (meth)acrylate units are converted into (meth)acrylic acid neutralization units, to obtain an ethylene-(meth)acrylate-(meth)acrylic acid neutralization copolymer or an ethylene-(meth)acrylic acid neutralization copolymer as a saponification product, and then a part of the (meth)acrylic acid neutralization units in the obtained saponification product is demetallized using a strong acid to be converted into (meth)acrylic acid units, whereby an ionomer resin containing (meth)acrylic acid units (A), (meth)acrylic acid neutralization units (B), ethylene units (C), and, as the case requires, (meth)acrylate units (D) is obtained.

[0091] In the aforementioned method (2), specifically, in the aforementioned method (1), all of the (meth)acrylic acid neutralization units in a saponification product obtained by saponifying an ethylene-(meth)acrylate copolymer using a strong base are demetallized using a strong acid to be converted into (meth)acrylic acid units, to obtain an ethylene-(meth)acrylic acid copolymer, and then a part of the (meth)acrylic acid units in the obtained demetallized product is neutralized using a metal ion to be converted into (meth)acrylic acid neutralization units, whereby an ionomer resin containing (meth)acrylic acid units (A), (meth)acrylic acid neutralization units (B), ethylene units (C), and, as the case requires, (meth)acrylate units (D) is obtained.

[0092] In the aforementioned method (1) and method (2), from the viewpoint of reducing the number of reactions to thereby easily improve the manufacturing efficiency of the ionomer resin, it is preferable to produce the ionomer resin by the method (1).

[0093] In the aforementioned production method (I) including a saponification step and a demetallization step, using an ethylene-(meth)acrylate copolymer (X) as a raw material, the aforementioned saponification step and / or the aforementioned demetallization step is performed in the presence of a transition metal, to obtain an ionomer resin containing a transition metal.

[0094] In the present application, "the saponification step and / or the demetallization step is performed in the presence of a transition metal" means that, for the saponification reaction in the saponification step and / or the demetallization reaction in the demetallization step, the reaction is performed in a state in which a transition metal is present in the reaction system. The transition metal present in the reaction system can be one alone or a combination of two or more. The method of making the transition metal present in the reaction system of the saponification reaction and / or the demetallization reaction is not particularly limited, and is, for example, any of a method of using a reaction apparatus containing a transition metal, a method of putting a member containing a transition metal into the reaction system, a method of adding an oxide, a hydroxide, a halide, a salt, or the like of a transition metal to the reaction system in a state of a powder and / or dispersing or dissolving them in a solvent, and the like.

[0095] The transition metal present in the reaction system is corroded by the strong base used in the saponification reaction and / or the strong acid used in the demetallization reaction, and thus the transition metal is contained in the ionomer resin. For example, if the transition metal present in the reaction system is corroded, the transition metal ion dissolved into the reaction system by ionization by corrosion is replaced by the hydrogen ion of the (meth)acrylic acid in the (meth)acrylic acid neutralizer unit (B) or the (meth)acrylic acid in the (meth)acrylic acid unit (A), and thus the transition metal can be contained in the ionomer resin in the form of the metal ion in the (meth)acrylic acid neutralizer unit (B). In addition, the transition metal ion dissolved into the reaction system reacts with the oxygen ion and / or halogen ion that can be present in the reaction system, and thus can be contained in the ionomer resin in the form of an oxide and / or halide.

[0096] As the aforementioned transition metal present in the reaction system, the above-mentioned transition metal that can be contained in the ionomer resin can be given. The transition metal present in the reaction system can be, for example, a pure metal formed of a single metal element, or an alloy containing at least one transition metal. In addition, the state of the transition metal is not particularly limited, and can be, for example, the state of a metal ion, an oxide, a hydroxide, a halide, a metal salt, or the like.

[0097] In one embodiment of the present application, from the viewpoint of easily improving the adhesion to glass under high humidity conditions, the transition metal present in the reaction system is preferably an alloy containing at least one transition metal, more preferably an alloy containing one or more metals selected from the group consisting of iron, nickel, manganese, and chromium, and further preferably an alloy containing two or more metals selected from the group consisting of iron, nickel, manganese, and chromium.

[0098] In one embodiment of the present application, from the viewpoint of improving the resistance to corrosion by the strong base used in the saponification step and the resistance to corrosion by the strong acid used in the demetallization step, and easily adjusting the content of the transition metal in the ionomer resin to 100 ppm or less, the aforementioned alloy containing at least one transition metal is preferably an austenitic stainless steel such as SUS304, SUS316, SUS316L, SUS312L, SUS310S, SUS836L, SUS890L, or the like; a nickel-based alloy such as HASTELLOY B2, HASTELLOY B3, HASTELLOY B4, HASTELLOY C4, HASTELLOY C2000, HASTELLOY C22, HASTELLOY C276, INCONEL X750, INCONEL 625, INCONEL 600, INCONEL 601, INCONEL 625, INCONEL 718, INCOLOY 825, or the like.

[0099] In one embodiment of the present application, the alloy preferably contains nickel and chromium in a total amount of 50% by mass or more from the viewpoint of improving the resistance to caustic corrosion of the strong base used in the saponification step and the resistance to acid corrosion of the strong acid used in the demetallization step, and easily adjusting the content of the transition metal in the ionomer resin to 100 ppm or less. The total content of nickel and chromium is more preferably 60% by mass or more, and further preferably 70% by mass or more. In addition, from the viewpoint of the durability of the alloy, the total content of nickel and chromium can be preferably 98% by mass or less, more preferably 95% by mass or less, and further preferably 90% by mass or less.

[0100] In one embodiment of the present application, the saponification step and / or the demetallization step is preferably performed in a reaction apparatus, at least a part of which contains at least one kind of transition metal. In this way, by performing the saponification step and / or the demetallization step in a reaction apparatus, at least a part of which contains at least one kind of transition metal, the saponification step and / or the demetallization step can be performed in the presence of a transition metal.

[0101] At least a part of the reaction apparatus containing at least one kind of transition metal is preferably an alloy containing at least one kind of transition metal, and as the alloy containing at least one kind of transition metal, the above-mentioned alloy can be mentioned, including the preferable modes. Among them, from the viewpoint of improving the resistance to caustic corrosion of the strong base used in the saponification step and the resistance to acid corrosion of the strong acid used in the demetallization step, and easily adjusting the content of the transition metal in the ionomer resin to 100 ppm or less, the alloy preferably contains nickel and chromium in a total amount of 50% by mass or more.

[0102] At least a part of the reaction apparatus is not particularly limited as long as it is a part that is contacted with the strong base used in the saponification reaction and / or the strong acid used in the demetallization reaction in the reaction apparatus, and thus corrosion of the transition metal can be performed, and for example, it can be a part that can be in liquid contact with a liquid containing the strong base and / or the strong acid, or a part that can be in contact with a gas containing the strong base and / or the strong acid.

[0103] In one embodiment of the present application, as at least a part of the reaction apparatus, it can be a part that constitutes an element of the reaction apparatus, and for example, at least one of a reaction tank, a stirring blade, a baffle, and a feed line that supplies the strong base and / or the strong acid into the reaction tank can be mentioned. These can be individual, or a combination of two or more. Note that the feed line that supplies the strong base and / or the strong acid into the reaction tank includes a pipe that can constitute the feed line, an addition nozzle, a valve, and the like.

[0104] In one embodiment of the present application, at least a portion of the aforementioned reaction device is preferably at least a portion of the reaction tank (e.g., the bottom, side, etc. of the reaction tank), and more preferably the entire reaction tank.

[0105] In one embodiment of the present application, in the aforementioned production method (I) for producing an ionomer resin using ethylene-(meth)acrylate copolymer (X) as a raw material, either or both of the saponification step and the aforementioned demetallization step can be performed in the presence of a transition metal.

[0106] As examples of the monomer constituting the (meth)acrylate unit of the aforementioned ethylene-(meth)acrylate copolymer (X), mention can be made of 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, allyl (meth)acrylate, and the like. Of these, the preferred monomer is methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, the more preferred monomer is methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, and the further preferred monomer is methyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, and the particularly preferred monomer is methyl (meth)acrylate. These (meth)acrylates can be one alone or a combination of two or more.

[0107] As specific examples of the ethylene-(meth)acrylate copolymer (X), mention can be made of ethylene-methyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-ethyl methacrylate copolymer, ethylene-n-propyl acrylate copolymer, ethylene-n-propyl methacrylate copolymer, ethylene-isopropyl acrylate copolymer, ethylene-isopropyl methacrylate copolymer, ethylene-n-butyl acrylate copolymer, ethylene-n-butyl methacrylate copolymer, ethylene-sec-butyl acrylate copolymer, ethylene-sec-butyl methacrylate copolymer, and the like.

[0108] As these copolymers, commercially available products, and those synthesized by the high-temperature high-pressure radical polymerization method described in US2013 / 0274424, Japanese Patent Application Publication No. 2006-233059, or Japanese Patent Application Publication No. 2007-84743 can be used. As the aforementioned commercially available products, for example, "ACRYFT" (registered trademark) WK307 manufactured by Sumitomo Chemical Co., Ltd., "Rexpearl" (registered trademark) A4250 manufactured by Japan Polyethylene Corporation, and the like can be given.

[0109] The content of the (meth)acrylate unit in the ethylene-(meth)acrylate copolymer (X) is preferably 6 mol% or more, more preferably 6.5 mol% or more, further preferably 7 mol% or more, particularly preferably 7.5 mol% or more, and, on the other hand, is preferably 10 mol% or less, more preferably 9.9 mol% or less, further preferably 9.5 mol% or less. The content of the (meth)acrylate unit in the copolymer (X) corresponds to the total content of the (meth)acrylic acid unit (A), and the (meth)acrylic acid neutralization product unit (B), and the (meth)acrylate unit (D) which is contained as appropriate, in the resulting ionomer resin, and therefore, if the content of the (meth)acrylate unit in the copolymer (X) is 6 mol% or more, the transparency, particularly the transparency at slow cooling, of the resulting ionomer resin is easily improved, and, on the other hand, if the content is 10 mol% or less, the elastic modulus of the resulting ionomer resin is easily improved.

[0110] The content of the (meth)acrylate unit in the copolymer (X) can be adjusted depending on the copolymerization ratio of ethylene to the (meth)acrylate. Note that the aforementioned content and the respective contents of the (meth)acrylic acid unit (A), the (meth)acrylic acid neutralization product unit (B), and the ethylene unit (C), and the (meth)acrylate unit (D) and other monomer units (for example, unit (A1) and unit (B1)) in the aforementioned ionomer resin can be similarly determined by thermal decomposition gas chromatography, nuclear magnetic resonance spectroscopy (NMR), and elemental analysis.

[0111] In one embodiment of the present application, the melt flow rate (MFR) of the ethylene-(meth)acrylate copolymer (X) measured according to JIS K7210 at 190°C under a load of 2.16 Kg is preferably 5 g / 10 min. or more, more preferably 10 g / 10 min. or more, further preferably 50 g / 10 min. or more, further more preferably 100 g / 10 min. or more, and preferably 400 g / 10 min. or less, more preferably 350 g / 10 min. or less, further preferably 300 g / 10 min. or less, further more preferably 250 g / 10 min. or less. If the MFR of the ethylene-(meth)acrylate copolymer (X) is within the above range, the molding processability and strength of the ionomer resin obtained are easily improved. The MFR of the ethylene-(meth)acrylate copolymer (X) can be adjusted depending on the polymerization degree and the content of the (meth)acrylate unit. The aforementioned MFR can be measured, for example, by the method described in the examples.

[0112] The weight average molecular weight of the ethylene-(meth)acrylate copolymer (X) is preferably 15,000 g / mole or more, more preferably 20,000 g / mole or more, further preferably 30,000 g / mole or more, and preferably 200,000 g / mole or less, more preferably 100,000 g / mole or less, from the viewpoint of easily improving the molding processability and strength of the ionomer resin obtained. In addition, the number average molecular weight of the ethylene-(meth)acrylate copolymer (X) is preferably 5,000 g / mole or more, more preferably 10,000 g / mole or more, further preferably 15,000 g / mole or more, and preferably 100,000 g / mole or less, more preferably 50,000 g / mole or less, from the same viewpoint. The aforementioned weight average molecular weight and number average molecular weight can be adjusted depending on the amount of the polymerization initiator and / or chain transfer agent at the time of polymerization. The molecular weight (weight average molecular weight and number average molecular weight) of these ethylene-(meth)acrylate copolymers (X) can be measured in terms of polystyrene by column (3 columns of TSKgel GMH HR-H (20) HT connected in series) and 1,2,4-trichlorobenzene solvent at a column temperature of 140°C.

[0113] The branching degree per 1,000 carbons of the ethylene-(meth)acrylate copolymer (X) is not particularly limited and is preferably 5 to 30, more preferably 6 to 20. The aforementioned branching degree can be adjusted depending on the polymerization temperature at the time of polymerization of the aforementioned copolymer (X). The aforementioned branching degree can be measured by dissolving the ethylene-(meth)acrylate copolymer (X) in deuterated o-dichlorobenzene and measuring by C-NMR using a reverse gate decoupling method. 13 C-NMR using a reverse gate decoupling method.

[0114] As examples of the strong base used in the saponification reaction in the saponification step, sodium hydroxide, potassium hydroxide, calcium hydroxide, and the like can be given, and from the viewpoints of solubility and economy of the solvent used in the saponification reaction, sodium hydroxide, potassium hydroxide are preferred.

[0115] The amount of the strong base added is, for example, preferably 100 to 300 moles, more preferably 120 to 250 moles, further preferably 150 to 200 moles, relative to 100 moles of the (meth)acryl unit of the ethylene-(meth)acrylate copolymer (X).

[0116] The method of adding the strong base is not particularly limited, and the strong base can be added to the liquid containing the ethylene-(meth)acrylate copolymer (X) through the gas phase portion in the reaction tank, or can be added directly to the liquid without passing through the gas phase portion in the reaction tank.

[0117] As examples of the solvent used in the saponification reaction, ethers such as tetrahydrofuran, dioxane, halogen-containing solvents such as chloroform, dichlorobenzene, ketones having 6 or more carbon atoms such as methyl butyl ketone, mixed solvents of a hydrocarbon compound and alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, aromatic compounds such as benzene, toluene, xylene, ethylbenzene, mixed solvents of an aromatic compound and an alcohol, and the like can be given. These solvents can be used alone or in combination of two or more.

[0118] Among these, from the viewpoint of solubility of the resin before and after the saponification reaction, the preferred solvent is a mixed solvent of a hydrocarbon compound and an alcohol, a mixed solvent of an aromatic compound and an alcohol, and the more preferred solvent is a mixed solvent of an aromatic compound such as toluene and an alcohol such as methanol. The ratio of the hydrocarbon compound or the aromatic compound to the alcohol in the aforementioned mixed solvent can be appropriately selected depending on the type of each solvent used, and for example, the mass ratio of the hydrocarbon compound or the aromatic compound to the alcohol (hydrocarbon compound or aromatic compound / alcohol) can be 50 / 50 to 90 / 10.

[0119] As the temperature at which the saponification reaction is performed, from the viewpoints of reactivity and solubility of the ethylene-(meth)acrylate copolymer (X), it is preferably 50°C or higher, more preferably 60°C or higher, further preferably 70°C or higher, more further preferably 80°C or higher, particularly preferably 100°C or higher. From the viewpoints of easily inhibiting excessive corrosion of the transition metal caused by the saponification reaction and easily adjusting the content of the transition metal in the ionomer resin to 100 mg / kg or less, the upper limit of the temperature is preferably 180°C or lower, more preferably 150°C or lower, further preferably 140°C or lower, more further preferably 130°C or lower, particularly preferably 120°C or lower.

[0120] The above saponification reaction can be performed in air or in a non-reactive gas such as nitrogen or argon. In addition, the above saponification reaction can be performed at any of normal pressure, under pressure, or under reduced pressure, and is preferably performed under pressure.

[0121] Examples of the strong acid used in the demetallation reaction in the demetallation step include hydrochloric acid, nitric acid, sulfuric acid, toluenesulfonic acid, and the like. From the viewpoint of easily removing the salt byproduct of the strong base used in the saponification reaction and the strong acid used in the demetallation reaction, inorganic acids such as hydrochloric acid, nitric acid, and sulfuric acid are preferred. The solvent used in the above demetallation can be selected from the same solvents as those used in the above saponification reaction.

[0122] In order to adjust the (meth)acrylic acid neutralization unit (B) to an arbitrary value, the amount of the strong acid to be added can be selected as an appropriate amount depending on the amount of the strong base to be added.

[0123] The method of adding the strong acid can be, for example, a method of adding the strong acid to the solution of the saponified product via the gas phase portion in the reaction tank, or a method of directly adding the strong acid in liquid form to the solution of the saponified product without passing through the gas phase portion in the reaction tank.

[0124] In the case of adding the strong acid to the solution of the saponified product via the gas phase portion in the reaction tank, from the viewpoint that the added strong acid is less likely to contact the wall surface of the gas phase portion of the reaction tank, the addition of the strong acid is preferably performed from the position directly above the region within 20% of the distance L from the center of the reaction tank to the wall surface of the reaction tank, via the gas phase portion. In addition, in the case of adding via the gas phase portion in the reaction tank, from the viewpoint that the added strong acid is less likely to contact the wall surface of the gas phase portion of the reaction tank, the addition of the strong acid is preferably performed from a position within 2 m, more preferably within 1 m, from the liquid surface. For example, in the case of supplying the strong acid to the reaction tank through a supply line, the feed port of the addition nozzle can be provided at a position within 20% of the distance L from the center of the reaction tank to the wall surface of the reaction tank and within 2 m or within 1 m from the liquid surface, or the strong acid can be added to the solution of the saponified product via the gas phase portion in the reaction tank. As described above, the added strong acid is less likely to contact the wall surface of the gas phase portion of the reaction tank, and thus it is easy to control the degree of progress of the corrosion of the transition metal caused by the strong acid, and it is easy to adjust the content of the transition metal in the ionomer resin to a range of 0.01 to 100 mg / kg.

[0125] In the case where the strong acid is directly added to the solution of the saponate not via the gas phase portion in the reaction tank, it is preferable to make the feed port of the addition nozzle for adding the strong acid to the solution of the saponate below the liquid surface of the solution of the saponate, so that the strong acid is directly added to the liquid not via the gas phase portion. In addition, it is preferable to provide the feed port at the bottom of the reaction tank, or the side portion of the reaction tank below the aforementioned liquid surface, so that the strong acid is directly added to the liquid not via the gas phase portion.

[0126] In one embodiment of the present application, it is preferable to perform the demetallization by adding the strong acid to the solution of the saponate not via the gas phase portion in the reaction tank, from the viewpoint of easily adjusting the content of the transition metal in the ionomer resin to 100 mg / kg or less.

[0127] In the aforementioned demetallization, it is preferable to perform the addition of the strong acid to the solution of the saponate while stirring the solution in the reaction tank, from the viewpoint of easily uniformly mixing the added strong acid. The stirring method is not particularly limited, and for example, it can be a method of stirring using an arbitrary shape of stirring blade that is generally used in industry, such as a Maxblend blade, a three-blade swept-back blade, a paddle blade, a multi-stage paddle blade, a turbine blade, an anchor blade, or the like. With respect to these stirring blades, it is preferable to use a Maxblend blade for stirring, from the viewpoint of easily uniformly mixing the added strong acid.

[0128] The temperature at the time of performing the aforementioned demetallization is preferably 20°C or higher, more preferably 30°C or higher, and further preferably 40°C or higher, from the viewpoint of easily reducing the viscosity of the reaction solution, and is preferably 180°C or lower, more preferably 150°C or lower, and further preferably 120°C or lower, from the viewpoint of easily suppressing excessive progress of corrosion of the transition metal caused by the demetallization reaction, and easily adjusting the content of the transition metal in the ionomer resin to 100 mg / kg or less.

[0129] The aforementioned demetallization can be performed in air, or in a non-active gas such as nitrogen, argon, or the like, as with the aforementioned saponification reaction. In addition, the aforementioned saponification reaction can be performed in any of normal pressure, under pressure, or under reduced pressure, and is preferably performed under pressure.

[0130] The neutralizing agent used when a part of the (meth)acrylic acid unit is neutralized and converted into a (meth)acrylic acid neutralization unit in the neutralization step of the above-described method (2) is not particularly limited as long as it is an ionic compound containing a metal ion. Examples of the aforementioned metal ion include alkali metal ions such as lithium, potassium, and sodium; alkaline earth metal ions such as magnesium and calcium; transition metal ions such as zinc, nickel, iron, and titanium; and aluminum ions. For example, in the case where the metal ion is a sodium cation, examples of the neutralizing agent include sodium hydroxide, sodium acetate, and sodium bicarbonate. Alternatively, a polymer such as an ionomer resin containing a sodium (meth)acrylate unit can be used as the neutralizing agent.

[0131] After the demetallation step, or in the case where the demetallation step is followed by a neutralization step, the ionomer resin of the present application can be obtained by separating and purifying the crude ionomer resin as a reaction product from the reaction mixture after the neutralization step. The separation and purification step in which the separation and purification are performed can be performed by a conventional method such as filtration, washing, concentration, reprecipitation, recrystallization, silica gel column chromatography, or the like.

[0132] In an embodiment of the present application, the aforementioned separation and purification step is preferably performed by adding a poor solvent to a solution of the crude ionomer resin to precipitate the particulate resin, and then washing the precipitated particulate resin with a washing liquid, from the viewpoint of easily washing and removing the by-produced salt.

[0133] The solution of the crude ionomer resin can be prepared by dissolving the obtained crude ionomer resin in a solvent after the demetallation step or the neutralization step after the demetallation step, or the reaction liquid obtained after the demetallation step or the neutralization step after the demetallation step can be used as the solution of the crude ionomer resin.

[0134] The solvent in the solution of the crude ionomer resin is not particularly limited as long as it is a solvent capable of dissolving the crude ionomer resin, and the same solvent as that used for the above-described saponification reaction can be exemplified. Among them, a mixed solvent of an aromatic compound such as toluene and an alcohol such as methanol is preferred from the viewpoint of the solubility of the crude ionomer resin. The ratio of the aromatic compound to the alcohol in the aforementioned mixed solvent can be appropriately selected depending on the type of each solvent used, and for example, the mass ratio of the aromatic compound to the alcohol (aromatic compound / alcohol) can be 50 / 50 to 90 / 10, and preferably 65 / 35 to 85 / 15.

[0135] From the viewpoint that the excess transition metal can be easily removed from the crude ionomer resin in which the particle size of the particulate resin is small and as a result, the excess transition metal is present in the crude ionomer resin, and the viewpoint that the by-produced salt can be easily removed, the concentration of the solution of the crude ionomer resin is preferably 30% by mass or less, more preferably 15% by mass or less, and in addition, preferably 1% by mass or more, more preferably 5% by mass or more.

[0136] From the viewpoint that the aggregation or gelling of the precipitated particulate resin can be easily inhibited, and the excess transition metal and the by-produced salt in the ionomer resin can be easily removed, the temperature of the solution of the crude ionomer resin is preferably the melting point of the ionomer resin or less, more preferably 60°C or less, and further preferably 50°C or less. In addition, from the viewpoint of the flowability of the solution of the crude ionomer resin, the aforementioned temperature is more preferably 25°C or more, and further preferably 30°C or more.

[0137] As the poor solvent to be added to the solution of the crude ionomer resin, there is no particular limitation as long as it is a solvent that is mixed with the solution of the crude ionomer resin and the ionomer resin is not dissolved, and for example, alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and the like; water; ketones such as acetone, methyl ethyl ketone, and the like; esters such as methyl acetate, ethyl acetate, and the like; ethers such as dimethyl ether, diethyl ether, tetrahydrofuran, and the like; hydrocarbon compounds such as n-hexane, cyclohexane, heptane, and the like, and the like can be given. They can be used alone as one kind, or two or more kinds in combination. Among them, from the viewpoint that the boiling point is low and thus the ionomer resin can be easily dried, and in addition, from the viewpoint that the excess transition metal and the by-produced salt in the particulate resin can be easily removed, the aforementioned poor solvent is preferably alcohols such as methanol, 2-propanol, and the like, water, and a mixed solvent thereof, and more preferably alcohols such as methanol and the like.

[0138] The amount of the poor solvent to be added can be appropriately selected depending on the concentration of the solution of the crude ionomer resin. For example, the amount of the poor solvent to be 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, with respect to 100 parts by mass of the solution of the crude ionomer resin. The upper limit of the amount of the poor solvent to be added is not particularly limited, and the upper limit of the amount of the poor solvent to be added is usually 1000 parts by mass or less, with respect to 100 parts by mass of the solution of the crude ionomer resin.

[0139] The method of adding the poor solvent to the solution of the crude ionomer resin is not particularly limited, and for example, the poor solvent can be added to the solution of the crude ionomer resin at once or in several portions by dropwise addition or the like. From the viewpoint of easily reducing the particle diameter of the particulate resin, thereby easily improving the removal of the excess transition metal and the by-produced salt in the particulate resin, and as a result, easily improving the transparency of the ionomer resin, the addition of the poor solvent is preferably performed in a short time, and more preferably at once. In the case of adding the poor solvent in several portions, it is preferable that the addition of the poor solvent be completed within 1 hour, more preferably within 30 minutes, and further preferably within 10 minutes.

[0140] After the addition of the poor solvent to the solution of the crude ionomer resin, the mixture of the solution of the crude ionomer resin and the poor solvent is preferably stirred. The stirring speed is not particularly limited, and the faster the stirring speed, the more easily the particulate particles having a small particle diameter are obtained. The stirring time is not particularly limited, and for example, as long as the particulate particles are precipitated and the mixture of the solution of the crude ionomer resin and the poor solvent becomes a slurry, the stirring is performed until then, and specifically, it is preferable that the stirring time be 1 second or more and 3 hours or less, more preferably 10 seconds or more and 1 hour or less, and further preferably 1 minute or more and 30 minutes or less.

[0141] From the viewpoint of increasing the specific surface area of the particulate resin, thereby easily removing the by-produced salt in the particulate resin, and in addition, from the viewpoint of easily reducing the content of the excess transition metal, and as a result, easily adjusting the content of the transition metal in the ionomer resin to be within the range of 0.01 to 100 mg / kg, the peak particle diameter of the particulate resin precipitated by the addition of the poor solvent to the solution of the crude ionomer resin is 700 μm or less, preferably 650 μm or less, more preferably 600 μm or less, and further preferably 550 μm or less. In addition, from the viewpoint of easily improving the filterability of the particulate resin and easily improving the manufacturing efficiency of the ionomer resin, it is preferable that the peak particle diameter be 50 μm or more, more preferably 70 μm or more, and preferably 80 μm or more.

[0142] The peak particle diameter of the particulate resin precipitated by the addition of the poor solvent to the solution of the crude ionomer resin can be adjusted depending on the concentration and the temperature of the solution of the crude ionomer resin. Specifically, if the concentration and / or the temperature of the solution of the crude ionomer resin are reduced, the peak particle diameter of the precipitated particulate resin can be reduced, and if the concentration and / or the temperature of the solution of the crude ionomer resin are increased, the peak particle diameter of the precipitated particulate resin can be increased. In addition, the peak particle diameter of the particulate resin can be adjusted by the method of adding the poor solvent and the stirring speed of the mixture of the solution of the crude ionomer resin and the poor solvent.

[0143] As the washing liquid for washing the precipitated particulate resin, there is no particular limitation as long as it is a solvent in which the ionomer resin is not dissolved. As examples of the preferred washing liquid, there can be mentioned alcohols such as methanol, ethanol, 1-propanol, 2-isopropanol, and the like; water; ketones such as acetone, methyl ethyl ketone, and the like; esters such as methyl acetate, ethyl acetate, and the like; and ethers such as dimethyl ether, diethyl ether, tetrahydrofuran, and the like. These can be used singly or in combination of two or more.

[0144] Among these washing liquids, from the viewpoint of easy removal of the excess transition metal and the by-produced salt, alcohols, water, and a mixture thereof are preferred. Further, from the viewpoint of making the specific gravity of the washing liquid smaller than that of the particulate resin, increasing the contact area between the washing liquid and the particulate resin, and thus easily improving the removal of the transition metal and the by-produced salt, easily removing impurities such as organic compounds contained in the particulate resin, and easily drying the ionomer resin obtained after the washing, the more preferred washing liquid is a mixture of water and an alcohol. From the viewpoint of easy drying and high compatibility with water, the preferred alcohol is methanol, ethanol, and more preferably methanol.

[0145] The ratio of water to alcohol (water / alcohol (mass %)) in the mixture of water and alcohol is preferably 20 / 80 to 80 / 20, and more preferably 30 / 70 to 70 / 30.

[0146] As examples of the method for washing the particulate resin with the washing liquid, there can be mentioned a method in which the particulate resin is filtered from the particulate resin dispersion from which the particulate resin is precipitated, the filtered particulate resin is mixed with the washing liquid, and then the particulate resin is filtered from the washing liquid. More specifically, there can be mentioned a method in which the particulate resin filtered from the aforementioned particulate resin dispersion is mixed with the washing liquid, the particulate resin is filtered from the washing liquid (hereinafter, also referred to as washing step (a)), and then the filtered particulate resin is mixed with a new washing liquid, and the particulate resin is filtered from the washing liquid (hereinafter, also referred to as washing step (b)) to perform the washing. From the viewpoint of easy removal of the transition metal and the by-produced salt contained in the particulate resin and the viewpoint of the manufacturing efficiency of the ionomer resin, in the case of a batch process, for example, it is preferred that the washing step (b) be performed 1 to 10 times after the washing step (a) is performed once, and the number of times of the washing step (b) after the washing step (a) is performed once is more preferably 1 to 6 times, and further preferably 1 to 4 times.

[0147] The amount of use of the aforementioned washing liquid per 1 washing step can be appropriately selected depending on the amount of the particulate resin to be washed. For example, the amount of use of the aforementioned washing liquid per 1 washing step is preferably 100 parts by mass to 2000 parts by mass, more preferably 200 parts by mass to 1000 parts by mass, and further preferably 300 parts by mass to 700 parts by mass, with respect to 100 parts by mass of the particulate resin at the time of drying.

[0148] The ionomer resin obtained by washing the granular resin with the washing liquid can be dried as needed. As the drying temperature, it is preferable to be below the melting point of the ionomer resin, and more preferable to be 80°C or lower.

[0149] The ionomer resin of the present application can also be produced by a method other than the aforementioned production method (I). As the aforementioned production method (I) other than the method by which the ionomer resin of the present application can be produced, for example, a method in which ethylene and (meth)acrylic acid are used as raw materials, a copolymer obtained by polymerizing them is partially neutralized, and a transition metal is added to the obtained partially neutralized product (hereinafter also referred to as production method (II)) can be given. In the aforementioned production method (II), an ionomer resin containing a transition metal in an amount of 0.01 to 100 mg / kg can be produced by a method comprising the following steps:

[0150] a step of copolymerizing ethylene and (meth)acrylic acid to obtain an ethylene-(meth)acrylic acid copolymer (copolymerization step),

[0151] a step of partially neutralizing the obtained ethylene-(meth)acrylic acid copolymer with a strong base (partial neutralization step), and

[0152] a step of adding a transition metal to the obtained partially neutralized product (addition step).

[0153] The method of obtaining the aforementioned partially neutralized product by the aforementioned copolymerization step and the aforementioned partial neutralization step can refer to the method of producing a resin in the specification of U.S. Patent No. 6518365, U.S. Patent No. 8399096.

[0154] A transition metal is added to the partially neutralized product obtained by the aforementioned copolymerization step and the aforementioned partial neutralization step, and mixed, whereby an ionomer resin in which the content of a transition metal in the resin is 0.01 to 100 mg / kg can be produced. As the transition metal that can be added to the aforementioned partially neutralized product, the transition metal that can be contained in the ionomer resin of the present application can be given. The state of the transition metal at the time of addition to the aforementioned resin is not particularly limited, and for example, it can be a transition metal oxide, a transition metal hydroxide, a transition metal halide, a transition metal salt, or the like, and it can also be added in a state of being dispersed or dissolved in a solvent.

[0155] The amount of the transition metal to be added is appropriately selected so as to be within the range in which the content of the transition metal in the ionomer resin is 0.01 to 100 mg / kg, and for example, it can be 0.01 x 10 -4 to 100 x 10 -4 mass parts, and it can be preferably 0.05 x 10 -4 to 50 x 10-4 mass, more preferably 0.1 x 10 -4 ~ 10 x 10 -4 mass, further preferably 0.2 x 10 -4 ~ 5 x 10 -4 mass.

[0156] For the mixing of the partial neutralization product and the transition metal in the foregoing, a mixing and stirring device, an extruder, or the like can be used for the mixing.

[0157] Further, the ionomer resin of the present application can also be produced by a method (hereinafter, also referred to as production method (III)) in which a transition metal is added to a crude ionomer resin obtained by carrying out the saponification step and the demetallization step in the absence of a transition metal in the foregoing production method (I). Further, the ionomer resin of the present application can also be produced by a method (hereinafter, also referred to as production method (IV)) in which a transition metal is added in the production of the foregoing partial neutralization product, for example, between the copolymerization step and the partial neutralization step in the foregoing production method (II). As the transition metal to be added in the production method (III) and the production method (IV), the same transition metal as in the production method (II) can be used.

[0158] In the foregoing production methods (I) to (IV), from the viewpoint of the ease of the production process, it is preferable that the ionomer resin be produced by the production method (I).

[0159] In an embodiment of the present application, the ionomer resin of the present application can also be produced by adding an additive as needed to the ionomer resin to produce a resin composition. The resin composition contains the ionomer resin of the present application and the additive.

[0160] As examples of the additive that can be contained in the resin composition, ultraviolet absorbers, age resistors, antioxidants, heat deterioration preventers, light stabilizers, anti-blocking agents, lubricants, release agents, polymer processing aids, antistatic agents, flame retardants, dyes and pigments, organic pigments, matting agents, phosphors, and the like can be given. Of these additives, ultraviolet absorbers, age resistors, antioxidants, heat deterioration preventers, light stabilizers, anti-blocking agents, lubricants, release agents, polymer processing aids, and organic pigments are preferable. In the case of addition, the additive can be one kind alone or a combination of two or more kinds.

[0161] In the present application, the resin composition can also contain a silane coupling agent or the like as an additive, but from the viewpoint of inhibiting the generation of crosslinking gels and thus easily obtaining a resin sheet having a good appearance, it is preferable that the resin composition not contain a bonding promoter.

[0162] The ultraviolet absorber is a compound having the ability to absorb ultraviolet rays, and can be said to mainly have the function of converting light energy into heat energy. As examples of the ultraviolet absorber, benzophenone-based, benzotriazole-based, triazine-based, benzoate-based, salicylate-based, cyanoacrylate-based, oxanilide-based, malonate-based, formamidine-based, and the like can be given. They can be one alone, or a combination of two or more.

[0163] The benzotriazole-based has a high effect of inhibiting the reduction in optical properties based on coloring or the like by ultraviolet irradiation, and is thus preferred as the ultraviolet absorber. As examples of the preferred benzotriazole-based, 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol (manufactured by BASF Corporation; trade name TINUVIN 329), 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (manufactured by BASF Corporation; trade name TINUVIN 234), 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-tert-octylphenol] (manufactured by ADEKA Corporation; LA-31), 2-(5-octylthio-2H-benzotriazol-2-yl)-6-tert-butyl-4-methylphenol, and the like can be given. They can be one alone, or a combination of two or more.

[0164] As examples of the triazine-based ultraviolet absorber, 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methylphenyl)-1,3,5-triazine (manufactured by ADEKA Corporation; LA-F70), a hydroxyphenyl triazine-based ultraviolet absorber (manufactured by BASF Corporation; TINUVIN 477, TINUVIN 460) belonging to an analog thereof, 2,4-diphenyl-6-(2-hydroxy-4-hexyloxyphenyl)-1,3,5-triazine, and the like can be given. They can be one alone, or a combination of two or more.

[0165] As the age resistor, a publicly known material can be exemplified. As examples of the specific age resistor, phenol-based compounds such as hydroquinone, hydroquinone monomethyl ether, 2,5-di-tert-butylphenol, 2,6-di(tert-butyl)-4-methylphenol, mono(or di, or tri)(a-methylbenzyl)phenol, and the like; bisphenol-based compounds such as 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), 4,4'-thiobis(3-methyl-6-tert-butylphenol), and the like; benzimidazole-based compounds such as 2-mercaptobenzimidazole, 2-mercaptomethylbenzimidazole, and the like; amine-ketone-based compounds such as 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline, a reaction product of diphenylamine with acetone, 2,2,4-trimethyl-1,2-dihydroquinoline polymer, and the like; aromatic secondary amine-based compounds such as N-phenyl-1-naphthylamine, alkylated diphenylamine, octylated diphenylamine, 4,4'-bis(a,a-dimethylbenzyl)diphenylamine, p(p-toluenesulfonamide)diphenylamine, N,N'-diphenyl-p-phenylenediamine, and the like; thiourea-based compounds such as 1,3-bis(dimethylaminopropyl)-2-thiourea, tributyl thiourea, and the like, and the like can be exemplified. They can be one alone, or a combination of two or more.

[0166] The antioxidant is one which is effective alone in preventing the oxidative deterioration of the resin in the presence of oxygen. For example, phosphorus-based antioxidants, hindered phenol-based antioxidants, sulfide-based antioxidants, and the like can be exemplified. These antioxidants can be one alone, or a combination of two or more. Among them, from the viewpoint of the effect of preventing the deterioration of the optical properties due to coloring, a phosphorus-based antioxidant, a hindered phenol-based antioxidant, and more preferably a combination of a phosphorus-based antioxidant and a hindered phenol-based antioxidant are preferred.

[0167] In the case of combining a phosphorus-based antioxidant and a hindered phenol-based antioxidant, the amount of the phosphorus-based antioxidant: the amount of the hindered phenol-based antioxidant is preferably 1:5 to 2:1, and more preferably 1:2 to 1:1 in terms of mass ratio.

[0168] As examples of the preferred phosphorus-based antioxidant, 2,2-methylenebis(4,6-di-tert-butylphenyl)octylphosphite (manufactured by ADEKA Corporation; trade name: ADEKASTAB HP-10), tris(2,4-di-tert-butylphenyl)phosphite (manufactured by BASF Corporation; trade name: IRGAFOS 168), 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane (manufactured by ADEKA Corporation; trade name: ADEKASTAB PEP-36), and the like can be exemplified. They can be one alone, or a combination of two or more.

[0169] As examples of the preferred hindered phenol-based antioxidant, there are, for example, pentaerythritol-tetra-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate (manufactured by BASF Corporation; trade name: IRGANOX 1010), octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate (manufactured by BASF Corporation; trade name: IRGANOX 1076), and the like. They can be one alone or a combination of two or more.

[0170] The heat deterioration preventive agent can prevent heat deterioration of the resin by capturing polymer radicals generated when exposed to high heat in a substantially oxygen-free state. As examples of the preferred heat deterioration preventive agent, there are, for example, 2-t-butyl-6-(3'-t-butyl-5'-methyl-hydroxybenzyl)-4-methylphenyl acrylate (manufactured by Sumitomo Chemical Co., Ltd.; trade name: Sumilizer GM), 2,4-di-t-pentyl-6-(3',5'-di-t-pentyl-2'-hydroxy-α-methylbenzyl)phenyl acrylate (manufactured by Sumitomo Chemical Co., Ltd.; trade name: Sumilizer GS), and the like. They can be one alone or a combination of two or more.

[0171] The light stabilizer is a compound that can be said to have a function of mainly capturing radicals generated under light-based oxidation. As examples of the preferred light stabilizer, there are, for example, hindered amines having a 2,2,6,6-tetraalkylpiperidine skeleton and the like. They can be one alone or a combination of two or more.

[0172] As examples of the anti-blocking agent, there are, for example, salts or esters of fatty acids, esters of polyhydric alcohols, inorganic salts, inorganic oxides, and particulate resins. As examples of the preferred anti-blocking agent, there are, for example, calcium stearate, calcium carbonate, calcium sulfate, magnesium sulfate, barium sulfate, silicon dioxide (manufactured by Evonik Corporation; trade name: Aerosil), and particulate acrylic resins. They can be one alone or a combination of two or more.

[0173] As examples of the lubricant, there are, for example, stearic acid, behenic acid, stearamidic acid, methylenebisstearamide, glyceryl hydroxystearate, paraffin wax, ketone wax, octanol, hydrogenated oil, and the like. They can be one alone or a combination of two or more.

[0174] As examples of the release agent, there are, for example, higher alcohols such as cetyl alcohol and stearyl alcohol; higher fatty acid glycerides such as stearic acid monoglyceride and stearic acid diglyceride; and the like. They can be one alone or a combination of two or more.

[0175] The polymer processing aid generally uses polymer particles having a particle diameter of 0.05 to 0.5 μm, which can be produced by an emulsion polymerization method. The polymer particles can be single-layer particles formed of a single composition ratio and a single intrinsic viscosity, or can be multi-layer particles formed of two or more kinds of polymers having different composition ratios or intrinsic viscosities. They can be one kind alone, or two or more kinds in combination. Among them, particles having a two-layer structure in which a polymer layer having a low intrinsic viscosity is provided in the inner layer and a polymer layer having a high intrinsic viscosity of 5 dl / g or more is provided in the outer layer are preferred. The intrinsic viscosity of the polymer processing aid is preferably 3 to 6 dl / g. If the intrinsic viscosity is too small, there is a tendency that the improvement effect on moldability is low, and if the intrinsic viscosity is too large, there is a tendency that the moldability of the copolymer is reduced.

[0176] As examples of the organic colorant, a compound having a function of converting ultraviolet rays into visible rays is preferably used. The organic colorant can be one kind alone, or two or more kinds in combination.

[0177] As examples of the fluorescent substance, a fluorescent pigment, a fluorescent dye, a fluorescent white dye, a fluorescent brightener, a fluorescent bleaching agent, and the like can be given. They can be one kind alone, or two or more kinds in combination.

[0178] In the case where these additives are added, the content of each additive can be appropriately selected within a range not impairing the effects of the present application, and the total content of the additives is preferably 7% by mass or less, more preferably 5% by mass or less, and further preferably 4% by mass or less, relative to the total mass of the resin composition.

[0179] Each additive can be added at the time of production of the ionomer resin, can be added after the production of the ionomer resin, or can be added at the time of production of the resin sheet described later.

[0180] In order to improve the convenience at the time of storage, transportation, or molding, the ionomer resin of the present application and the resin composition in the present application can be formed into a pellet or the like. In the case where the ionomer resin and the resin composition are pelletized, for example, the resulting strand can be cut by a melt extrusion method. From the viewpoint of easily stabilizing the discharge from the extruder, the temperature of the resin or the resin composition at the time of melt extrusion at the time of pelletization by the melt extrusion method is preferably 150°C or higher, and more preferably 170°C or higher. In addition, from the viewpoint of suppressing the thermal decomposition of the resin to cause deterioration, the aforementioned temperature is preferably 250°C or lower, and more preferably 230°C or lower. The ionomer resin of the present application and the resin composition in the present application have high resistance to thermal decomposition, and thus, when pelletized by the melt extrusion method, the ionomer resin is less likely to be thermally decomposed to cause problems such as the generation of black foreign matters.

[0181] [Resin sheet]

[0182] The present application also includes a resin sheet having one or more layers comprising the ionomer resin of the present application. The resin sheet of the present application has one or more layers comprising the ionomer resin of the present application (hereinafter, also referred to as layer (x)). The layer (x) is a layer comprising the ionomer resin of the present application or the resin composition of the present application.

[0183] The resin sheet of the present application can be composed of only the layer (x), or can be a laminate comprising at least one layer (x). As the aforementioned laminate, there is no particular limitation, and examples thereof include a laminate comprising two or more layers (x), a laminate comprising one or more layers (x) and one or more other layers, and the like. In the case where the layer (x) or the other layer is plural, the resin or the resin composition constituting each layer can be the same or different.

[0184] As the aforementioned other layer, a layer comprising a publicly known resin can be exemplified. As the resin, for example, polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyurethane, polytetrafluoroethylene, an acrylic resin, polyamide, polyacetal, polycarbonate, polyesters such as polyethylene terephthalate and polybutylene terephthalate, cyclic polyolefin, polyphenylene sulfide, polytetrafluoroethylene, polysulfone, polyethersulfone, polyarylate, liquid crystal polymer, polyimide, thermoplastic elastomer, and the like can be used. In addition, the other layer can contain one or more of the aforementioned additives, and additives such as a plasticizer, an anti-blocking agent, a pigment, a dye, a heat shielding material (for example, inorganic heat shielding fine particles or organic heat shielding material having infrared absorbing ability), and a functional inorganic compound, as needed.

[0185] In one embodiment of the present application, the resin sheet of the present application preferably has a concave-convex structure on the surface by a publicly known method such as melt fracture or embossing, from the viewpoint of excellent debubbling property at the time of heat pressure bonding of the resin sheet to a substrate.

[0186] The thickness of one layer of the layer (x) in the resin sheet of the present application is preferably 0.1 mm or more, more preferably 0.2 mm or more, further preferably 0.3 mm or more, particularly preferably 0.4 mm or more, and, on the other hand, is preferably 5 mm or less, more preferably 4 mm or less, further preferably 2 mm or less, particularly preferably 1 mm or less. In the case where the layer (x) in the resin sheet is plural, the thickness of one layer of the plural layer (x) in the resin sheet can be the same or different.

[0187] The thickness of the resin sheet of the present application is preferably 0.1 mm or more, more preferably 0.2 mm or more, further preferably 0.3 mm or more, further more preferably 0.4 mm or more, particularly preferably 0.5 mm or more, more particularly preferably 0.6 mm or more, further particularly preferably 0.7 mm or more, and especially preferably 0.75 mm or more, and is preferably 20 mm or less, more preferably 15 mm or less, further preferably 10 mm or less, further more preferably 5 mm or less, particularly preferably 4 mm or less, more particularly preferably 2 mm or less, and further particularly preferably 1 mm or less.

[0188] The thickness of the resin sheet can be measured by a method known in the art, such as a contact or non-contact thickness meter. The resin sheet can be in a state of being wound in a roll shape or in a state of being a single sheet.

[0189] In a suitable embodiment of the present application, the resin sheet of the present application can have the haze, water absorption haze, slow cooling haze, adhesion to glass, and yellowness of the ionomer resin of the present application.

[0190] The resin sheet of the present application preferably has a low water content from the viewpoint of preventing foaming during the production of laminated glass. The water content of the resin sheet is preferably 1 mass% or less, more preferably 0.5 mass% or less, further preferably 0.02 mass% or less, and particularly preferably 0.01 mass% or less. The aforementioned water content can be measured by the Coulomb titration method.

[0191] Method for producing resin sheet

[0192] The method for producing the resin sheet of the present application is not particularly limited. For example, the ionomer resin of the present application and optional additives are uniformly mixed, and then a layer (x) can be produced by a known film production method such as an extrusion method, a calendering method, a pressurization method, a solution casting method, a melt casting method, a blow molding method, or the like. The layer (x) can be used as a resin sheet alone. Alternatively, if necessary, two or more layers of the layer (x) or one or more layers of the layer (x) and one or more other layers can be stacked by press molding or the like to form a laminated resin sheet, or two or more layers of the layer (x) or one or more layers of the layer (x) and one or more other layers can be molded by a co-extrusion method to form a laminated resin sheet. In the case where the layer (x) or the other layer is a plurality of layers, the resins or resin compositions constituting the respective layers can be the same or different.

[0193] Among known film-forming methods, methods for producing resin sheets using an extruder are suitable. To stabilize the ejection of the resin from the extruder and reduce mechanical failures, the resin temperature during extrusion is preferably 150°C or higher, more preferably 170°C or higher. To reduce resin decomposition and the resulting degradation of the resin, the resin temperature during extrusion is preferably 250°C or lower, more preferably 230°C or lower. Furthermore, to effectively remove volatile substances, it is preferred to remove them from the vent of the extruder by reducing pressure.

[0194] [Laminated glass interlayer and laminated glass]

[0195] The resin sheet of the present invention can be suitably used as an interlayer film for laminated glass (also referred to as an interlayer film). Therefore, the present invention includes an interlayer film for laminated glass comprising the resin sheet of the present invention. Furthermore, the present invention includes laminated glass comprising: two glass sheets; and an interlayer film for laminated glass of the present invention disposed between the two glass sheets. The laminated glass of the present invention, comprising the interlayer film for laminated glass comprising the resin sheet, can exhibit excellent transparency.

[0196] As the glass plate laminated with the interlayer film of the present invention, for example, inorganic glass such as float glass, polished glass, patterned glass, wired glass, and heat-absorbing glass can also be used, as well as conventionally known organic glasses such as polymethyl methacrylate and polycarbonate. These can be colorless or colored. A single type or a combination of two or more types can be used. The thickness of each glass plate is preferably 100 mm or less, and the thicknesses of the two glass plates can be the same or different.

[0197] Laminated glass, in which the resin sheet of the present invention is sandwiched between two sheets of glass, can be produced using conventionally known methods. Examples include methods using a vacuum laminator, a vacuum bag, a vacuum ring, and a roller. Furthermore, methods include temporary pressure bonding using the aforementioned methods and then placing the sheets in an autoclave for final bonding.

[0198] When using a vacuum laminator, for example, in a 1×10 -6 ~1×10 -1 Laminated glass can be produced by laminating glass sheets, an interlayer film, and any layers (such as adhesive resin layers) under reduced pressure of 0.1 MPa at 60 to 200°C, particularly 80 to 160°C. The method using a vacuum bag or a vacuum ring is described in, for example, European Patent No. 1235683. -2 ~3×10 -2 Laminated glass can be produced by laminating glass plates, an interlayer film, and any other layers at a pressure of approximately 100 MPa at a temperature of 100 to 160°C.

[0199] As an example of the production method using a roll, a method in which a glass sheet, an interlayer film, and an optional layer are stacked, degassed at a temperature lower than the flow initiation temperature of the interlayer film using a roll, and then further pressed at a temperature close to the flow initiation temperature can be given. Specifically, for example, a method in which the glass sheet, the interlayer film, and the optional layer are heated to 30 to 70°C using an infrared heater or the like, degassed using a roll, and then further heated to 50 to 120°C, and pressed using a roll can be given.

[0200] In the case where the glass sheet, the interlayer film, and the optional layer are pressed using the above method and then further pressed in an autoclave, the operating conditions in the autoclave process can be appropriately selected depending on the thickness and the composition of the laminated glass, and for example, it is preferable to perform the process at a pressure of 0.5 to 1.5 MPa and at 100 to 160°C for 0.5 to 3 hours.

[0201] The ionomer resin of the present application has high transparency and high adhesion to glass, and thus the laminated glass of the present application is excellent in transparency. In one embodiment of the present application, the haze of the laminated glass having an interlayer film with a sheet thickness of 0.8 mm is preferably 1.0% or less, more preferably 0.8% or less, and further preferably 0.5% or less. The smaller the haze, the higher the transparency of the ionomer resin, and the lower limit is not particularly limited, and for example, can be 0.01%. Note that the haze of the laminated glass is measured with a haze meter in accordance with JIS K7136:2000.

[0202] In one embodiment of the present application, the laminated glass of the present application is excellent in transparency even after being heated to 140°C and then slowly cooled to 23°C at a rate of 0.1°C / minute from 140°C. The haze (slowly cooled haze) of the laminated glass having an interlayer film with a sheet thickness of 0.8 mm after being heated to 140°C and then slowly cooled to 23°C at a rate of 0.1°C / minute from 140°C is preferably 5.0% or less, more preferably 4.5% or less, further preferably 4.0% or less, and particularly preferably 3.0% or less. The smaller the haze, the higher the transparency of the laminated glass, and thus the lower limit is not particularly limited, and for example, can be 0.01%. The slowly cooled haze is also measured with a haze meter in accordance with JIS K7136:2000.

[0203] The laminated glass of the present application is less colored, and preferably as colorless as possible. In the case where the sheet thickness of the interlayer film is 0.8 mm, the yellow index (YI) of the laminated glass of the present application is preferably 2.0 or less, more preferably 1.8 or less, further preferably 1.5 or less, and particularly preferably 1.0 or less. The smaller the yellow index (YI), the less the colorability of the ionomer resin, and thus the lower limit is not particularly limited, and for example, can be 0. Note that the yellow index (YI) is measured with a color difference meter in accordance with JIS Z8722.

[0204] The adhesion of the interlayer film of the laminated glass of the present application to glass can be evaluated in terms of the peel energy of the glass and the ionomer resin as determined by a peel test. The peel energy of the glass and the ionomer resin as determined under standard conditions (23°C, 50% RH) is preferably 2 kJ / m 2 or more, more preferably 2.5 kJ / m 2 or more, further preferably 3 kJ / m 2 or more, particularly preferably 3.5 kJ / m 2 or more. In addition, the adhesion to glass under high humidity conditions can be evaluated in terms of the peel energy of the glass and the ionomer resin as determined by a peel test under wet (Wet) conditions. The peel energy of the glass and the ionomer resin as determined under wet conditions is preferably 0.05 kJ / m 2 or more, more preferably 0.1 kJ / m 2 or more, further preferably 0.15 kJ / m 2 or more, particularly preferably 0.2 kJ / m 2 or more. The upper limit of the aforementioned peel energy under standard conditions and under high humidity conditions is not particularly limited and can be 10 kJ / m 2 or less. The aforementioned peel test can be performed by, for example, the method described in International Publication No. 2019-027865 as Peel Adhesion Measurement. The peel energy as determined under the aforementioned standard conditions and wet conditions can be determined, for example, by the method described in the examples.

[0205] The adhesion of the interlayer film of the laminated glass of the present application to the glass plate can also be evaluated, for example, by a compression shear strength test described in International Publication No. 1999-058334. The compression shear strength is preferably 15 MPa or more, more preferably 20 MPa or more, particularly preferably 25 MPa or more. In addition, from the viewpoint of easily improving the penetration resistance of the laminated glass, the compression shear strength can be 50 MPa or less.

[0206] As described above, the resin sheet having one or more layers containing the ionomer resin of the present application is useful as an interlayer film of laminated glass. From the viewpoint of excellent adhesion to a substrate such as glass, transparency, and self-standing property, it is particularly preferable as an interlayer film of laminated glass for structural materials. In addition, it is not limited to an interlayer film of laminated glass for structural materials, but is also suitable as an interlayer film of laminated glass for various uses such as mobile bodies such as automobiles, buildings, solar cells, and the like, but is not limited to these uses.

[0207] Examples

[0208] The present application will be described specifically below by way of examples and comparative examples, but the present application is not limited to the following examples.

[0209] 〔Content of monomer unit〕

[0210] (Starting resin)

[0211] The ethylene-(meth)acrylate copolymer used as a starting material in the examples and comparative examples was dissolved in deuterated toluene or deuterated THF, and the content of the (meth)acrylate unit (D) was analyzed by1H-NMR (400 MHz, manufactured by JEOL Ltd.). 1 The composition was quantified by1H-NMR (400 MHz, manufactured by JEOL Ltd.).

[0212] (Ionomer resin)

[0213] For the ionomer resins obtained in the examples and comparative examples, the content of the (meth)acrylic acid unit (A), the (meth)acrylic acid neutralization unit (B), the ethylene unit (C), and the (meth)acrylate unit (D) in the ionomer resin was analyzed as follows.

[0214] The ionomer resins obtained in the examples and comparative examples were each dissolved in a mixed solvent of dehydrated toluene / dehydrated acetic acid (75 / 25 mass%), and after being reacted at 100°C for 2 hours, were reprecipitated in a mixed solvent of acetone / water (80 / 20 mass%) to convert the (meth)acrylic acid neutralization unit (B) to the (meth)acrylic acid unit (A). The obtained resin was sufficiently washed with water and dried, and the dried resin was subjected to the following (1) to (3).

[0215] (1) The components of the monomer units constituting the resin were analyzed by thermal decomposition GC-MS.

[0216] (2) The acid value of the resin was measured in accordance with JIS K0070:1992.

[0217] (3) The resin was subjected to1H-NMR (400 MHz, manufactured by JEOL Ltd.) measurement using a mixed solvent of deuterated toluene and deuterated methanol. 1 H-NMR (400 MHz, manufactured by JEOL Ltd.) measurement.

[0218] (4) In addition, the ionomer resins obtained in the examples and comparative examples were each subjected to microwave decomposition pretreatment using nitric acid, and the kind and amount of metal ions of the (meth)acrylic acid neutralization unit (B) were identified by ICP emission spectroscopy analysis (manufactured by Thermo Fisher Scientific, "iCAP6500 Duo").

[0219] The kinds and structures of the (meth)acrylate unit (D) and the (meth)acryl unit (A) are identified from the above (1). From this information, and the information of the above (2) and (3), the ratio of the ethylene unit (C) / the (meth)acrylate unit (D) / the total of the (meth)acryl unit (A) and the (meth)acrylic acid neutralization unit (B) is calculated. Further, from the information of the above (4), the ratio of the ethylene unit (C) / the (meth)acrylate unit (D) / the (meth)acryl unit (A) / the (meth)acrylic acid neutralization unit (B) is calculated.

[0220] 〔Content of transition metal in ionomer resin〕

[0221] To 0.1 g of the ionomer resin obtained in the Examples and Comparative Examples, 6.0 ml of nitric acid was added, and decomposition was performed using a microwave decomposition device (manufactured by CEM, "Discover SP-D80"). The aforementioned decomposition was performed as follows: the ionomer resin to which nitric acid was added was put in a container attached to the microwave decomposition device, and the temperature was raised from the initial temperature (23°C) to 210°C over 4 minutes, and after the temperature was raised, the temperature was maintained at 210°C for 4 minutes, and then, cooling was performed using a fan for air cooling in the decomposition device until the temperature of the container was reduced to 80°C.

[0222] After cooling, the solution of the obtained decomposed product was diluted in a 50-ml PFA measuring flask, and then, filtration was performed using a filter having a thickness of 0.45 μm, and then, the content of the transition metal in the resin composition was measured using a high-frequency inductively coupled plasma emission spectrometer (manufactured by Thermo Fisher SCIENTIFIC, "iCAP6500Duo").

[0223] 〔Flowability (melt flow rate (MFR))〕

[0224] The melt flow rate of the raw material resins used in the Examples and Comparative Examples, and the ionomer resins obtained in the Examples and Comparative Examples was measured in accordance with JIS K7210. Specifically, each resin was melted in a cylinder, and the amount of resin extruded per 10 minutes (g / 10 minutes) was measured under the conditions of 190°C and a load of 2.16 kg, from a die having a nominal orifice diameter of 2.095 mm provided at the bottom of the cylinder.

[0225] 〔Thermal decomposition resistance〕

[0226] The heat decomposition resistance of the ionomer resins obtained in the Examples and Comparative Examples was evaluated in accordance with JIS K7120-1987. Specifically, the weight reduction ratio when each resin was heated from 20°C to 550°C was measured using a simultaneous thermogravimetric-differential thermal analyzer TG-DTA7200 (manufactured by Hitachi High-Tech Science Corporation) at a temperature increase rate of 10°C / minute in a nitrogen atmosphere at a flow rate of 50 mL / minute. The weight at 200°C was taken as a reference, and the temperature at which the weight reduction ratio became 1% (1% weight reduction temperature (Td1)) was taken as an index of the heat decomposition resistance.

[0227] 〔Yellow index (YI)〕

[0228] The ionomer resins obtained in the Examples and Comparative Examples were each melt-kneaded at 210°C, and the melt-kneaded product was compression-molded at a pressure of 4.9 MPa (50 kgf / cm 2 ) for 5 minutes under heating at 210°C to obtain a resin sheet having a thickness of 0.8 mm. The obtained resin sheet was measured using a color-difference meter "ZE-2000" (trade name) manufactured by Nippon Denshoku Industries Co., Ltd. in accordance with JIS Z 8722. The value of the yellow index calculated in accordance with JIS K 7373 was taken as the yellow index (YI) on the basis of the obtained value.

[0229] 〔Transparency under high humidity conditions (water absorption haze)〕

[0230] The transparency under high humidity conditions was evaluated by measuring the water absorption haze in the following manner. The resin sheet obtained in the same manner as described above was cut into a square of 50 mm, and the cut sample was left to stand in ion exchange water at 23°C for 300 hours to obtain a water absorption sample. After wiping off the water adhering to the surface of the water absorption sample taken out of the ion exchange water, the haze of the water absorption sample was measured using a haze meter HZ-1 (manufactured by Suga Test Instruments Co., Ltd.) in accordance with JIS K7136:2000.

[0231] 〔Transparency upon slow cooling (slow cooling haze)〕

[0232] The resin sheet obtained in the same manner as described above was sandwiched between two sheets of float glass having a thickness of 2.7 mm, and a temporary bonded body was obtained using a vacuum laminator (Model 1522N manufactured by Nisshinbo MECHATRONICS Co., Ltd.) at 100°C by reducing the pressure in the vacuum laminator for 1 minute, and then applying a pressure of 30 kPa for 5 minutes while maintaining the reduced pressure and the temperature. The obtained temporary bonded body was put into an autoclave, and a laminated glass having a size of 30 cm square was obtained by treatment at 140°C and 1.2 MPa for 30 minutes.

[0233] The interlayer glass obtained in the above-described method was heated to 140°C and then slowly cooled to 23°C at a rate of 0.1°C / min. The haze of the interlayer glass after the slow cooling operation was measured with a haze meter HZ-1 (manufactured by Suga Test Instruments Co., Ltd.) in accordance with JIS K7136:2000.

[0234] 〔Adhesion to glass under standard conditions (dry conditions)〕

[0235] The interlayer glass obtained in the same manner as described above was subjected to a peeling test in the 90° direction at a rate of 1 cm / min at 23°C and 50% RH using a universal testing machine (MTS Criterion M45) in accordance with the method described in International Publication No. 2019 / 027865 as Peel Adhesion Measurement, and the peeling force P was measured. Dry The peeling energy γ under dry conditions was calculated from the peeling force P Dry , the width W of the peeling test piece, by the following formula.

[0236] Peeling energy γ under dry conditions Dry 〔kJ / m 2 〕 = P Dry 〔kJ / m〕 / W〔m〕.

[0237] 〔Adhesion to glass under wet conditions〕

[0238] The peeling energy under wet conditions was measured by the following method, and thereby the adhesion to glass under high humidity conditions was evaluated. The interlayer glass obtained in the same manner as described above was subjected to a peeling test in the 90° direction at a rate of 1 cm / min at 23°C and 50% RH using a universal testing machine (MTS Criterion M45) in accordance with the method described in International Publication No. 2019 / 027865 as Peel Adhesion Measurement. After the test piece was peeled by 100 mm, water was dropped between the glass and the peeled surface to become a wet state, and the peeling was performed again at a rate of 0.025 cm / min, and the peeling force P Wet under the wet state was measured. Wet The peeling energy γ under wet conditions was calculated from the peeling force P Wet under the wet state, the width W of the peeling test piece, by the following formula.

[0239] Peeling energy γ under wet conditions Wet 〔kJ / m 2 〕 = P Wet 〔kJ / m〕 / W〔m〕.

[0240] 〔Appearance evaluation of the resin sheet〕

[0241] The 30 cm square-sized laminated glass obtained in the same manner as the above method was visually observed to confirm the presence or absence of the gelled product of the resin sheet, and evaluated according to the following criteria.

[0242] A: The number of the confirmed gelled product was less than 5

[0243] B: The number of the confirmed gelled product was 5 or more

[0244] In the above criteria, the A evaluation means that the appearance of the resin sheet is good.

[0245] 〔Raw material resin〕

[0246] In the examples and comparative examples, the methyl methacrylate (MMA) modification amount or the ethyl acrylate (EA) modification amount of each ethylene-(meth)acrylate copolymer (X) used as a raw material of the ionomer resin, and the MFR are shown in Table 1.

[0247] For example, as the EMMA1, "ACRYFT" (registered trademark) WK307 manufactured by Sumitomo Chemical Co., Ltd. can be used, and as the EEA1, "REXPEARL" (registered trademark) A4250 manufactured by Japan Polyethylene Corporation can be used.

[0248] [Table 1]

[0249]

[0250] 〔Material of the reaction tank〕

[0251] In the examples and comparative examples using ethylene-(meth)acrylate copolymer (X) as a raw material, the material and the composition of each reaction tank in which the saponification reaction and the demetallization reaction of the ethylene-(meth)acrylate copolymer (X) were performed are shown below.

[0252] HASTELLOY B2: 68 mass% of nickel, 28 mass% of molybdenum, 2 mass% of iron, 1 mass% of chromium, 1 mass% of cobalt

[0253] HASTELLOY C22: 56 mass% of nickel, 13 mass% of molybdenum, 3 mass% of iron, 22 mass% of chromium, 6 mass% of others

[0254] SUS312L: 20 mass% of nickel, 7 mass% of molybdenum, 47 mass% of iron, 21 mass% of chromium, 5 mass% of others

[0255] SUS316L: 15 mass% of nickel, 3 mass% of molybdenum, 59 mass% of iron, 18 mass% of chromium, 5 mass% of others

[0256] SUS304: Ni 11 mass%, Fe 64 mass%, Cr 20 mass%, others 5 mass%

[0257] SUS316: Ni 14 mass%, Mo 3 mass%, Fe 60 mass%, Cr 18 mass%, others 5 mass%

[0258] [Example 1]

[0259] A pressure-resistant vessel equipped with Maxblend blades made of HASTELLOY B2 was used as a reaction tank. 100 parts by mass of EMMA 1 in Table 1 was introduced into the aforementioned reaction tank, and toluene 233 parts by mass was added thereto, and the EMMA 1 was dissolved by stirring at 60°C under 0.02 MPa pressure. To the obtained solution, methanol solution (20 mass%) of sodium hydroxide 96 parts by mass was added, and the EMMA 1 was saponified by stirring at 100°C for 4 hours, and a part of the methyl methacrylate unit was converted into a sodium methacrylate unit. Subsequently, after the solution was cooled to 50°C, hydrochloric acid (20 mass%) 83 parts by mass was directly added to the reaction liquid, and a part of the sodium methacrylate unit was converted into methacrylic acid by stirring at 50°C for 1 hour, and a crude ionomer resin solution was obtained.

[0260] In the obtained crude ionomer resin solution, a mixed solvent of toluene / methanol (75 / 25 mass%) was added so that the crude ionomer resin concentration became 10 mass%, and the solution was diluted. Subsequently, after the obtained diluted solution of the crude ionomer resin was adjusted to 34°C, methanol at 34°C 430 parts by mass was added to the aforementioned diluted solution with respect to 100 parts by mass of the crude ionomer resin solution, and the particulate resin was precipitated. Subsequently, the obtained particulate resin was filtered, and the filtered particulate resin 100 parts by mass was mixed with a mixed solvent of water / methanol (50 / 50 mass%) 600 parts by mass. The slurry obtained by the aforementioned mixing was stirred at 40°C for 1 hour, and after that, the particulate resin was filtered at room temperature. The particulate resin was washed further three times using a mixed solvent of water / methanol (50 / 50 mass%), and a washed ionomer resin was obtained.

[0261] The obtained ionomer resin was vacuum-dried for 8 hours or more, and analysis was performed, and the properties were evaluated. The analysis results and evaluation results of the ionomer resin 1 are shown in Table 2 and Table 3.

[0262] [Example 2]

[0263] A pressure-resistant container made of HASTELLOY C22 was used instead of a pressure-resistant container made of HASTELLOY B2 as a reaction tank, EMMA2 was used instead of EMMA1, and hydrochloric acid was added dropwise from a nozzle at a distance of 1 m from the liquid surface of the upper portion of the reaction tank, through the gas phase portion, to the reaction solution, and otherwise, the same operation as in Example 1 was performed to obtain an ionomer resin. The analysis results and evaluation results of the obtained ionomer resin are shown in Tables 2 and 3.

[0264] [Example 3]

[0265] A pressure-resistant container made of HASTELLOY C22 was used instead of a pressure-resistant container made of HASTELLOY B2 as a reaction tank, EMMA2 was used instead of EMMA1, and hydrochloric acid was added dropwise from a nozzle at a distance of 1 m from the liquid surface of the upper portion of the reaction tank, through the gas phase portion, to the reaction solution, and otherwise, the same operation as in Example 1 was performed to obtain an ionomer resin. The analysis results and evaluation results of the obtained ionomer resin are shown in Tables 2 and 3.

[0266] [Example 4]

[0267] A pressure-resistant container made of SUS312L was used instead of a pressure-resistant container made of HASTELLOY B2 as a reaction tank, EMMA2 was used instead of EMMA1, and otherwise, the same operation as in Example 1 was performed to obtain an ionomer resin. The analysis results and evaluation results of the obtained ionomer resin are shown in Tables 2 and 3.

[0268] [Example 5]

[0269] A pressure-resistant container made of SUS316L was used instead of a pressure-resistant container made of HASTELLOY B2 as a reaction tank, EEA1 was used instead of EMMA1, and otherwise, the same operation as in Example 1 was performed to obtain an ionomer resin. The analysis results and evaluation results of the obtained ionomer resin are shown in Tables 2 and 3.

[0270] [Example 6]

[0271] After ethylene and methacrylic acid were copolymerized to obtain an ethylene-(meth)acrylic acid copolymer according to the method described in U.S. Patent No. 6518365, the copolymer was partially neutralized with sodium hydroxide. To 100 parts by mass of the obtained partially neutralized product, 3.4 x 10 -4 parts by mass of a 20% aqueous solution of ferrous (II) chloride was added in an extruder to obtain a transition metal-containing ionomer resin. The analysis results and evaluation results of the obtained ionomer resin are shown in Tables 2 and 3.

[0272] [Comparative Example 1]

[0273] A pressure-resistant vessel made of SUS304 was used instead of a pressure-resistant vessel made of HASTELLOY B2 as a reaction tank, EMMA2 was used instead of EMMA1, and hydrochloric acid was added dropwise from a nozzle located 3 m from the liquid surface of the upper portion of the reaction tank via a gas phase portion, and otherwise, the same operation as in Example 1 was performed to obtain an ionomer resin. The analysis results and evaluation results of the obtained ionomer resin are shown in Table 2 and Table 3.

[0274] [Comparative Example 2]

[0275] A pressure-resistant vessel made of SUS316 was used instead of a pressure-resistant vessel made of SUS304 as a reaction tank, and otherwise, the same operation as in Comparative Example 1 was performed to obtain an ionomer resin. The analysis results and evaluation results of the obtained ionomer resin are shown in Table 2.

[0276] [Comparative Example 3]

[0277] A pressure-resistant vessel made of HASTELLOY C22 was used instead of a pressure-resistant vessel made of HASTELLOY B2 as a reaction tank, EMMA3 was used instead of EMMA1, and otherwise, the same operation as in Example 1 was performed to obtain an ionomer resin. The analysis results and evaluation results of the obtained ionomer resin are shown in Table 2 and Table 3.

[0278] [Comparative Example 4]

[0279] An ethylene-(meth)acrylic acid copolymer was obtained by copolymerizing ethylene and methacrylic acid according to the method described in U.S. Patent No. 6518365, and then the copolymer was partially neutralized with sodium hydroxide to obtain an ionomer resin. The analysis results and evaluation results of the obtained ionomer resin are shown in Table 2 and Table 3.

[0280] [Comparative Example 5]

[0281] A resin composition was obtained by melt-kneading 100 parts by mass of the ionomer resin obtained in Comparative Example 4 and 0.2 parts by mass of 3-glycidoxypropylmethyldiethoxysilane as a silane coupling agent. The analysis results and evaluation results of the obtained resin composition are shown in Table 2 and Table 3.

[0282] [Table 2]

[0283]

[0284] [Table 3]

[0285]

[0286] As shown in Table 3, it was confirmed that the ionomer resin obtained in the examples had lower water absorption haze, higher transparency even in a water-absorbed state, higher peeling energy under a wet condition, higher adhesion to glass even under a high humidity condition, and higher resistance to thermal decomposition, as compared with the ionomer resins obtained in the comparative examples. In addition, the resin sheet manufactured using the ionomer resin obtained in the examples had less gelled product and good appearance.

Claims

1. An ionomer resin comprising; a (meth) acrylic acid unit (A), a (meth) acrylic acid neutralization unit (B), and an ethylene unit (C), a total content of the unit (A) and the unit (B) is 7.5 to 10 mol% based on the total monomer units constituting the ionomer resin, a content of a transition metal in the ionomer resin is 0.01 to 50 mg / kg, the transition metal is one or more metals selected from the group consisting of iron, nickel, manganese, and chromium, the transition metal contains at least iron.

2. The ionomer resin of claim 1, wherein, the ionomer resin further comprises a (meth) acrylic ester unit (D), a total content of the unit (A), the unit (B), and the unit (D) is 7.5 to 10 mol% based on the total monomer units constituting the ionomer resin.

3. A resin sheet having one or more layers comprising the ionomer resin according to claim 1 or 2.

4. A laminated glass interlayer comprising the resin sheet according to claim 3.

5. A laminated glass having: two glass sheets; and the laminated glass interlayer according to claim 4 disposed between the two glass sheets.

6. A method for producing the ionomer resin according to claim 1 or 2, comprising: a step of saponifying an ethylene-(meth) acrylic ester copolymer with a strong base, and a step of demetallizing a saponified product obtained by the step with a strong acid, the saponification step and / or the demetallization step is performed in the presence of a transition metal.

7. The method of claim 6, wherein, the demetallization is performed by adding the strong acid to a solution of the saponified product.

8. The method of claim 6 or 7, wherein, the saponification step and / or the demetallization step is performed using a reaction apparatus, at least a part of the reaction apparatus is an alloy comprising 50 mass% or more of nickel and chromium as transition metals in total.

9. The method of claim 8, wherein, at least a part of the reaction apparatus is at least one selected from the group consisting of a reaction tank, a stirring blade, a baffle, and a feed line that supplies the strong base and / or the strong acid into the reaction tank.

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