Composition, multilayer structure, molded body, packaging container, and method for producing composition

Abstract

In order to provide a composition having both excellent thermal stability and heat discoloration resistance, a composition is prepared comprising an ethylene-vinyl alcohol copolymer (A), a copolymer (B) comprising an ethylene structural unit and a structural unit represented by formula (1), and a titanium compound (C), the content of the titanium compound (C) in the composition is 0.001 ppm by mass or more and less than 10 ppm by mass in terms of metal.

Description

Technical Field

[0001] This invention relates to compositions, multilayer structures, molded bodies, packaging material containers, and methods for manufacturing compositions. Background Technology

[0002] Ethylene-vinyl alcohol copolymer (hereinafter, sometimes referred to as "EVOH") has superior oil resistance, organic solvent resistance, rigidity, hardness, abrasion resistance, and gas barrier properties compared to other resins, and is therefore widely used as a thermoplastic resin.

[0003] For such EVOH, various solutions have been proposed to improve its performance depending on the application. For example, Patent Documents 1 and 2 propose solutions to improve impact resistance and flowability without compromising these preferred properties. Furthermore, Patent Documents 3 and 4 propose solutions to improve long-term moldability and resistance to flexural fatigue. Patent Document 5 proposes a solution to improve adhesion to hydrophobic thermoplastic resins without compromising gas barrier properties.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Publication No. 42-3185

[0007] Patent Document 2: Japanese Patent Publication No. 5-2699

[0008] Patent Document 3: Japanese Patent No. 4642195

[0009] Patent Document 4: Japanese Patent Application Publication No. 2001-288323

[0010] Patent Document 5: Japanese Patent No. 5610955 Summary of the Invention

[0011] The problem the invention aims to solve

[0012] Although the performance of various EVOHs described in Patent Documents 1 to 5 has been improved depending on the application, there is still room for improvement in terms of balancing thermal stability and resistance to heat staining.

[0013] Therefore, in this invention, under such circumstances, a composition with excellent thermal stability and resistance to heat staining is provided.

[0014] Solution for solving the problem

[0015] However, the inventors conducted in-depth research in view of the above situation and found that by using a composition containing EVOH (A), a copolymer (B) containing ethylene structural units and structural units shown in formula (1) described later, and a titanium compound (C), and setting the content of the titanium compound (C) in metal conversion to be more than 0.001 ppm by mass and less than 10 ppm by mass of the composition, it is possible to obtain an EVOH composition with excellent thermal stability and resistance to heat coloring.

[0016] That is, the present invention has the following aspects.

[0017] [1] A composition comprising EVOH (A), copolymer (B), and titanium compound (C), wherein the copolymer (B) comprises ethylene structural units and structural units represented by the following formula (1), and the titanium compound (C) in the composition is present in a content of 0.001 ppm by mass or more and less than 10 ppm by mass in metal conversion.

[0018]

[0019] (where R1 is an alkoxycarbonyl group (-COOR)) A ) or acyloxy group (-OOCR) A ), the R A (This refers to an aliphatic hydrocarbon group containing 1 to 20 hydrogen or carbon atoms.)

[0020] [2] The composition according to [1], wherein R represented by formula (1) A It consists of a hydrogen atom or an aliphatic hydrocarbon group with 1 to 4 carbon atoms.

[0021] [3] The composition according to [1] or [2], wherein the copolymer (B) comprises an ethylene-vinyl carboxylate copolymer and / or an ethylene-acrylate copolymer (B1).

[0022] [4] The composition according to any one of [1] to [3], wherein the copolymer (B) comprises:

[0023] Ethylene-vinyl carboxylate copolymers and / or ethylene-acrylate copolymers (B1); and

[0024] The copolymer selected from the group consisting of ethylene-vinyl carboxylate copolymers having polar groups, ethylene-acrylate copolymers having polar groups, ethylene-vinyl carboxylate-maleic anhydride copolymers, and ethylene-acrylate-maleic anhydride copolymers (B2).

[0025] [5] According to the composition of [4], wherein the polar group in the ethylene-carboxylic acid ethylene copolymer having a polar group is a carboxyl group or a carbonyl group.

[0026] [6] The composition according to [4] or [5], wherein the copolymer (B) is an ethylene-vinyl carboxylate copolymer having polar groups and / or an ethylene-acrylate copolymer having polar groups, and at least one of the polar groups is a carboxyl group.

[0027] [7] The composition according to [5] wherein the carbonyl group in the carbonyl group is maleic anhydride.

[0028] [8] The composition according to any one of [1] to [7], wherein the content of titanium compound (C) in the composition is 0.001 ppm by mass or more and 5 ppm by mass or less.

[0029] [9] The composition according to any one of [1] to [8], wherein the mass ratio (A / B) of EVOH (A) to the copolymer (B) is 70 / 30 to 99 / 1.

[0030]

[10] The composition according to any one of [1] to [9], wherein the mass ratio (A / B) of EVOH (A) to the copolymer (B) is 70 / 30 to 85 / 15.

[0031]

[11] The composition according to [4] or [5], wherein the mass ratio (B2 / B1) of the copolymer (B2) to the copolymer (B1) is 0.01 to 10.

[0032]

[12] The composition according to [4] or [5], wherein the mass ratio of EVOH (A) to the total mass of the copolymer (B1) and the copolymer (B2) [A / (B1+B2)] is 50 / 50 to 99 / 1.

[0033]

[13] A recycling composition, wherein the composition of any one of [1] to

[12] is used for recycling.

[0034]

[14] A recyclable material layer comprising any one of the compositions described in [1] to

[12] .

[0035]

[15] A multilayer structure having a layer comprising any one of the compositions described in [1] to

[12] .

[0036]

[16] The multilayer structure according to

[15] also has an adhesive resin layer.

[0037]

[17] A molded body formed from the multilayer structure described in

[15] or

[16] .

[0038]

[18] A packaging material container, which is formed from the multi-layer structure described in

[15] .

[0039]

[19] A method for manufacturing a composition, which is a method for manufacturing the composition described in any one of [1] to

[12] , comprising a step of mixing the EVOH (A), the copolymer (B) and the titanium compound (C).

[0040]

[20] A method for manufacturing a composition, which is the method for manufacturing the composition described in [4] or [5], comprising a step of mixing the EVOH (A), the copolymer (B1), the copolymer (B2) and the titanium compound (C).

[0041]

[21] A method for manufacturing a multilayer structure, comprising: a step of obtaining a composition by a method for manufacturing the composition described in

[19] or

[20] ; and a step of forming a layer comprising the composition obtained by said step as at least one layer of the multilayer structure.

[0042] The effects of the invention

[0043] The present invention is a composition comprising EVOH (A), copolymer (B), and titanium compound (C), wherein the copolymer (B) comprises ethylene structural units and structural units shown in formula (1) described later, and the titanium compound (C) is set to a specific trace amount of metal-converted content of 0.001 ppm by mass and less than 10 ppm by mass of the composition, thus exhibiting excellent thermal stability and resistance to heat-induced coloration.

[0044] Therefore, the composition is suitable for use as an EVOH resin layer in a multilayer structure formed by laminating resins with different properties. Detailed Implementation

[0045] The present invention will now be described based on examples of methods for carrying out the invention. However, the present invention is not limited to the embodiments described below.

[0046] It should be noted that in this invention, "X and / or Y (X and Y are arbitrary configurations)" refers to at least one of X and Y, and specifically refers to only X, only Y, or X and Y.

[0047] When expressed as "x~y" (where x and y are any numbers), unless otherwise specified, it includes the meaning of "above x and below y", and also includes the meaning of "preferably greater than x" or "preferably less than y".

[0048] When expressed as "above x" (where x is any number) or "below y" (where y is any number), it also implies "preferably greater than x" or "preferably lower than y".

[0049] In addition, regarding the numerical ranges described step by step in this specification, the upper limit value or the lower limit value of the numerical range in a certain stage can be arbitrarily combined with the upper limit value or the lower limit value of the numerical range in other stages. Moreover, in the numerical ranges described in this specification, the upper limit value or the lower limit value of this numerical range can also be replaced with the values shown in the examples.

[0050] In addition, in the present invention, respectively, “(meth)acrylic” means acrylic or methacrylic, “(meth)acryloyl” means acryloyl or methacryloyl, and “(meth)acrylate” means acrylate or methacrylate. In addition, “acrylic resin” means a resin obtained by polymerizing a copolymerization component containing at least one (meth)acrylate monomer.

[0051] In the present invention, the “main component” means a component that has a great influence on the properties of the object, and the content of this component is usually 50% by mass or more in the object, preferably 55% by mass or more, more preferably 60% by mass or more, further preferably 70% by mass or more, and may also be 100% by mass.

[0052] An EVOH composition according to an embodiment of the present invention (hereinafter sometimes referred to as “this EVOH composition”) contains EVOH (A) (hereinafter sometimes referred to as “component A”), copolymer (B) (hereinafter sometimes referred to as “component B”), and titanium compound (C) (hereinafter sometimes referred to as “component C”). The copolymer (B) contains an ethylene structural unit and a structural unit represented by the following formula (1), and the content of the titanium compound (C) in terms of metal is set to be 0.001 mass ppm or more and less than 10 mass ppm of this EVOH composition.

[0053]

[0054] (In the formula, R1 is an alkoxycarbonyl (-COOR A ) or an acyloxy (-OOCR A ), and the R A represents a hydrogen atom or an aliphatic hydrocarbon group having 1 to 20 carbon atoms.)

[0055] Hereinafter, each component will be described.

[0056] <Component A>

[0057] The EVOH(A) used in this EVOH composition is typically a resin obtained by saponification following copolymerization of ethylene and vinyl ester monomers. It is a known water-insoluble thermoplastic resin as a saponified form of ethylene-vinyl alcohol copolymer or ethylene-vinyl acetate copolymer. Any known polymerization method can be used, such as solution polymerization, suspension polymerization, emulsion polymerization, etc., typically using methanol as a solvent. The saponification of the resulting ethylene-vinyl ester copolymer can also be carried out using known methods.

[0058] That is, the EVOH(A) used in this invention is mainly composed of ethylene and vinyl alcohol structural units, and contains a certain amount of unsaponified and residual vinyl ester structural units. It should be noted that EVOH is also commonly referred to as "ethylene-vinyl ester copolymer saponification".

[0059] Vinyl acetate is representatively used as the aforementioned vinyl ester monomer due to its ease of market availability and / or efficient impurity handling during manufacturing. Other vinyl ester monomers include, for example, aliphatic vinyl esters such as vinyl formate, vinyl propionate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, vinyl neovalerate, vinyl decanoate, vinyl laurate, vinyl stearate, and vinyl tert-carbonate, and aromatic vinyl esters such as vinyl benzoate. Among these, aliphatic vinyl ester monomers with 3 to 20 carbon atoms are preferred, more preferably 4 to 10 carbon atoms, and particularly preferably 4 to 7 carbon atoms are preferred. They are typically used alone, but multiple types may also be used simultaneously as needed.

[0060] The content of ethylene structural units in the EVOH(A), measured based on ISO 14663, is typically 20-60 mol%, preferably 21-55 mol%, more preferably 22-50 mol%, and particularly preferably 23-45 mol%. By setting this content above the lower limit, there is a tendency for excellent gas barrier properties and melt-forming properties at high humidity; by setting this content below the upper limit, there is a tendency for excellent gas barrier properties.

[0061] The degree of saponification of the vinyl ester component in the EVOH(A) is determined based on JIS K6726 (wherein, a solution of EVOH uniformly dissolved in water / methanol solvent), and is typically 90-100 mol%, preferably 95-100 mol%, and particularly preferably 99-100 mol%. By making this degree of saponification above the lower limit, there is a tendency for excellent gas barrier properties, thermal stability, and moisture resistance.

[0062] Furthermore, the melt flow rate (MFR) of the EVOH(A) (210°C, 2160g load) is typically 0.5~100g / 10min, preferably 1~50g / 10min, and particularly preferably 3~35g / 10min. By setting the MFR below the upper limit, there is a tendency for excellent film-forming properties. Conversely, by setting the MFR above the lower limit, there is a tendency for easier melt extrusion.

[0063] In addition to ethylene structural units and vinyl alcohol structural units (including unsaponified vinyl ester structural units), the EVOH(A) used in this EVOH composition may further contain structural units from the comonomers shown below. Examples of such comonomers include: α-olefins such as propylene, isobutylene, α-octene, α-dodecene, and α-octadecene; hydroxyl-containing α-olefins such as 3-buten-1-ol, 4-penten-1-ol, and 3-buten-1,2-diol, and / or their esters, acylates, and other hydroxyl-containing α-olefin derivatives; hydroxymethyl vinylidene diacetate esters such as 1,3-diacetoxy-2-methylenepropane, 1,3-dipropionyloxy-2-methylenepropane, and 1,3-dibutyryloxy-2-methylenepropane; unsaturated carboxylic acids or their salts, partially alkyl esters, fully alkyl esters, nitriles, amides, or acid anhydrides; unsaturated sulfonic acids or their salts; vinylsilane compounds; vinyl chloride; styrene, etc. These may be used alone or in combination of two or more.

[0064] Furthermore, as the aforementioned EVOH(A), EVOH that has undergone "post-modification" such as urethane esterification, acetalization, cyanoethylation, or oxidative olefination can also be used.

[0065] Furthermore, among the modified EVOH(A) described above, EVOH(A) with primary hydroxyl groups introduced into the side chain through copolymerization is preferred in terms of improved secondary molding properties such as stretching and / or vacuum / compression molding, and EVOH(A) with a 1,2-diol structure in the side chain is particularly preferred.

[0066] In addition, the EVOH (A) used in this EVOH composition can be a mixture with different other EVOHs. Examples of such other EVOHs include EVOHs with different contents of ethylene structural units, EVOHs with different degrees of saponification, EVOHs with different melt flow rates (MFR) (210°C, 2160g load), EVOHs with different other copolymer components, and EVOHs with different amounts of modification (e.g., EVOHs with different contents of structural units containing primary hydroxyl groups in the side chain).

[0067] The content of EVOH (A) contained in the present EVOH composition is not particularly limited. It is preferably that EVOH (A) is the main component (that is, the content of EVOH (A) contained in the present EVOH composition is 50% by mass or more), more preferably 55% by mass or more, further preferably 60% by mass or more, particularly preferably 70% by mass or more, particularly preferably 80% by mass or more, and most preferably 90% by mass or more.

[0068] <Component B>

[0069] Component B used together with the above EVOH (A) in the present EVOH composition is a copolymer (B) containing an ethylene structural unit and a structural unit represented by the following formula (1).

[0070]

[0071] (wherein, R1 is an alkoxycarbonyl (-COOR A ) or an acyloxy (-OOCR A ), and the R A represents a hydrogen atom or an aliphatic hydrocarbon group having 1 to 20 carbon atoms.)

[0072] By containing Component B, the present EVOH composition has excellent mechanical strength and excellent flexibility. From this viewpoint, even if it does not contain resins such as PA, PVDC, PET, PVOH, and PVC which usually have excellent mechanical strength, a multilayer structure containing the present EVOH composition tends to exhibit excellent mechanical strength.

[0073] As Component B, usually R A represented by formula (1) is a hydrogen atom or an aliphatic hydrocarbon group having 1 to 20 carbon atoms. From the viewpoint of structural stability, it is preferred that R A represented by formula (1) is a hydrogen atom or an aliphatic hydrocarbon group having 1 to 4 carbon atoms. When R1 is an acyloxy group, it is preferably an ethylene-vinyl carboxylate copolymer, and when R1 is an alkoxycarbonyl group, it is more preferably an ethylene-acrylate copolymer.

[0074] They are usually used alone, and multiple kinds can be used simultaneously as needed. For example, an ethylene-vinyl carboxylate copolymer and / or an ethylene-acrylate copolymer (B1) (hereinafter sometimes referred to as "Component B1") can be contained.

[0075] The density of the above Component B is a value measured based on JIS K7112, and is usually 0.85 to 0.99 g / cm 3 Preferably it is 0.86 to 0.98 g / cm 3 More preferably it is 0.87 to 0.97 g / cm 3When the above density is set within the said range, a tendency to further enhance the effects of the present invention can be observed.

[0076] The content of Component B contained in this EVOH composition is not particularly limited. Relative to this EVOH composition, it is preferably 50% by mass or less, more preferably 45% by mass or less, particularly preferably 40% by mass or less, especially preferably 35% by mass or less, and most preferably 30% by mass or less. It should be noted that the lower limit of the content is usually 1% by mass or more, preferably 15% by mass or more, and particularly preferably 20% by mass or more.

[0077] That is, the content of Component B contained in this EVOH composition is preferably 1 to 50% by mass, more preferably 5 to 45% by mass, particularly preferably 10 to 40% by mass, especially preferably 15 to 35% by mass, and most preferably 20 to 30% by mass.

[0078] In addition, the mass ratio (A / B) of EVOH (Component A) to Component B is preferably 50 / 50 to 99 / 1, more preferably 70 / 30 to 85 / 15, and particularly preferably 70 / 30 to 80 / 20. When the above mass ratio (A / B) is set within the said range, a tendency for more excellent thermal stability can be observed.

[0079] <Component B1>

[0080] Ethylene - vinyl acetate copolymer is a resin obtained by copolymerizing ethylene and vinyl acetate - based monomers. In addition, ethylene - acrylate copolymer is a resin obtained by copolymerizing ethylene and acrylate - based monomers.

[0081] As the above vinyl acetate - based monomers, there is no particular limitation as long as they are conventionally known monomers. For example, the number of carbon atoms of the acyloxy group in the vinyl acetate - based monomers is 1 to 18, more preferably 2 to 8, and particularly preferably 2 to 6. They are usually used alone, and multiple kinds can also be used simultaneously as needed. From the aspect of easy availability in the market and / or good impurity treatment efficiency during manufacturing, vinyl acetate is typically preferably used.

[0082] As for the aforementioned acrylate monomers, there are no particular limitations as long as they are conventionally known acrylate monomers. For example, the number of carbon atoms in the alkoxy carbonyl group of the acrylate monomer is preferably 1 to 18, more preferably 2 to 8, and particularly preferably 2 to 6. Among these, aliphatic (meth)acrylate monomers are preferred from the perspectives of excellent copolymerization properties, excellent film strength, ease of processing, and ease of raw material availability. Representative examples include methyl (meth)acrylate, ethyl (meth)acrylate, and n-butyl (meth)acrylate, with methyl (meth)acrylate and ethyl (meth)acrylate being particularly preferred. They are usually used alone, but multiple types can also be used simultaneously as needed.

[0083] Specifically, components such as ethylene-vinyl acetate copolymer (EVA), ethylene-methyl acrylate copolymer (EMA), and ethylene-ethyl acrylate copolymer (EEA) can be listed as B1 components.

[0084] The melt flow rate (MFR) (190°C, 2160 g load) of the above-mentioned ethylene-vinyl carboxylate copolymer is typically 0.5 to 50 g / 10 min, preferably 0.5 to 20 g / 10 min, more preferably 1 to 10 g / 10 min, particularly preferably 2 to 9 g / 10 min, and most preferably 3 to 8 g / 10 min. By setting the MFR within the aforementioned range, a tendency to further improve thermal stability can be observed.

[0085] The vinyl carboxylate monomer content of the ethylene-vinyl carboxylate copolymer is preferably 1 to 50% by mass, more preferably 5 to 40% by mass, and even more preferably 7 to 35% by mass. When the vinyl carboxylate monomer content is set within the above range, an excellent balance between softness and heat resistance can be observed.

[0086] The MFR (190°C, 2160 g load) of the above-mentioned ethylene-acrylate copolymer is typically 0.5~100 g / 10 min, preferably 0.5~50 g / 10 min, more preferably 1~35 g / 10 min, particularly preferably 2~20 g / 10 min, and especially preferably 3~15 g / 10 min. By setting the above-mentioned MFR within the range, a tendency to further improve thermal stability can be observed.

[0087] The acrylate monomer content of the above-mentioned ethylene-acrylate copolymer is preferably 1 to 50% by mass, more preferably 5 to 40% by mass, and even more preferably 10 to 30% by mass. When the above-mentioned acrylate monomer content is set within the range, an excellent balance between softness and durability can be observed.

[0088] The content of the B1 component contained in this EVOH composition is not particularly limited. Relative to this EVOH composition, it is preferably 30% by mass or less, more preferably 25% by mass or less, particularly preferably 20% by mass or less, especially preferably 15% by mass or less, and most preferably 10% by mass or less. It should be noted that the lower limit of the content is usually 0.1% by mass or more, preferably 0.5% by mass or more, and particularly preferably 1% by mass or more.

[0089] That is, when the B1 component is included in this EVOH composition, the content of the B1 component is preferably 0.1 to 30% by mass, more preferably 0.5 to 25% by mass, particularly preferably 1 to 20% by mass, especially preferably 1 to 15% by mass, and most preferably 1 to 10% by mass.

[0090] In addition, the mass ratio of EVOH (A component) to the B1 component (A / B1) is preferably 70 / 30 to 99 / 1, more preferably 70 / 30 to 85 / 15, and particularly preferably 70 / 30 to 80 / 20. If the above mass ratio (A / B1) is within the said range, a tendency of more excellent thermal stability can be observed.

[0091] <B2 component>

[0092] In this EVOH composition, as the B component used together with the above EVOH (A component), it is more preferably to contain at least one copolymer (B2 component) selected from the group consisting of an ethylene-vinyl carboxylate copolymer and / or an ethylene-acrylate copolymer (B1 component) and an ethylene-vinyl carboxylate copolymer having a polar group, an ethylene-acrylate copolymer having a polar group, an ethylene-vinyl carboxylate-maleic anhydride copolymer, and an ethylene-acrylate-maleic anhydride copolymer.

[0093] That is, at least one copolymer selected from the group consisting of an ethylene-vinyl carboxylate copolymer having a polar group, an ethylene-acrylate copolymer having a polar group, an ethylene-vinyl carboxylate-maleic anhydride copolymer, and an ethylene-acrylate-maleic anhydride copolymer used as the B2 component is a copolymer obtained by modifying a resin obtained by copolymerizing ethylene and a vinyl carboxylate monomer to have a polar group; or a copolymer obtained by copolymerizing ethylene with a vinyl carboxylate monomer having a polar group as the vinyl carboxylate monomer; or a copolymer obtained by copolymerizing a resin obtained by copolymerizing ethylene and an acrylate monomer with a monomer having a polar group; or a copolymer obtained by copolymerizing ethylene with a monomer having a polar group.

[0094] As the above vinyl carboxylate monomers, the vinyl carboxylate monomers described in the B1 component can be used. They are usually used alone or multiple kinds can be used simultaneously as needed.

[0095] As the aforementioned acrylate monomers, the acrylate monomers described in component B1 can be used. They are usually used alone, or multiple monomers can be used simultaneously as needed.

[0096] As for the polar groups in the aforementioned monomers, carboxyl groups and / or carbonyloxy groups are preferred, and carbonyloxy carbonyl groups are more preferred. Examples of monomers containing carboxyl groups include acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, and citraconic acid. Additionally, examples of monomers containing carbonyloxy carbonyl groups include maleic anhydride. These can be used alone or in combination of two or more.

[0097] The melt flow rate (MFR) (190°C, 2160 g load) of the aforementioned ethylene-vinyl carboxylate copolymer with polar groups is typically 0.5 to 50 g / 10 min, preferably 0.5 to 30 g / 10 min, particularly preferably 1 to 20 g / 10 min, and especially preferably 3 to 20 g / 10 min. By setting the MFR within the aforementioned range, a tendency to further improve thermal stability can be observed.

[0098] The MFR (190°C, 2160 g load) of the aforementioned ethylene-acrylate copolymer with polar groups is typically 0.5 to 100 g / 10 min, preferably 0.5 to 50 g / 10 min, particularly preferably 1 to 35 g / 10 min, especially preferably 1 to 20 g / 10 min, and most preferably 3 to 20 g / 10 min. By setting the MFR within the aforementioned range, a tendency to further improve thermal stability can be observed.

[0099] The MFR (190°C, 2160 g load) of the above-mentioned ethylene-vinyl carboxylate-maleic anhydride copolymer is typically 0.5~100 g / 10 min, preferably 0.5~50 g / 10 min, particularly preferably 1~35 g / 10 min, especially preferably 1~20 g / 10 min, and most preferably 3~20 g / 10 min. By setting the above-mentioned MFR within the aforementioned range, a tendency to further improve thermal stability can be observed.

[0100] The MFR (190°C, 2160 g load) of the above-mentioned ethylene-acrylate-maleic anhydride copolymer is typically 0.5~100 g / 10 min, preferably 0.5~50 g / 10 min, particularly preferably 1~35 g / 10 min, especially preferably 1~20 g / 10 min, and most preferably 3~20 g / 10 min. By setting the above-mentioned MFR within the aforementioned range, a tendency to further improve thermal stability can be observed.

[0101] The density of component B2 mentioned above is based on values ​​determined using JIS K7112, typically ranging from 0.85 to 0.99 g / cm³.3 The preferred value is 0.86~0.98 g / cm³. 3 More preferably, it is 0.87~0.97 g / cm³. 3 If the density is set within the aforementioned range, a tendency can be observed to further enhance the effectiveness of the present invention.

[0102] Specifically, as the aforementioned component B2, an example of an ethylene-carboxylic acid ethylene ester copolymer having polar groups is maleic anhydride EVA.

[0103] Examples of ethylene-acrylate copolymers with polar groups include maleic anhydride ethylene-ethyl acrylate copolymers.

[0104] Examples of ethylene-vinyl carboxylate-maleic anhydride copolymers include ethylene-vinyl acetate-maleic anhydride terpolymers.

[0105] Examples of ethylene-acrylate-maleic anhydride copolymers include ethylene-methyl acrylate-maleic anhydride terpolymers, ethylene-ethyl acrylate-maleic anhydride terpolymers, and ethylene-butyl acrylate-maleic anhydride terpolymers.

[0106] The content of component B2 is not particularly limited, but is preferably 30% by mass or less, more preferably 25% by mass or less, particularly preferably 20% by mass or less, especially preferably 15% by mass or less, and most preferably 10% by mass or less, relative to this EVOH composition. It should be noted that the lower limit of the content is usually 0.1% by mass or more, preferably 0.5% by mass or more, and particularly preferably 1% by mass or more.

[0107] That is, when the EVOH composition contains B2, the content of B2 is preferably 0.1 to 30% by mass, more preferably 0.5 to 25% by mass, particularly preferably 1 to 20% by mass, especially preferably 1 to 15% by mass, and most preferably 1 to 10% by mass.

[0108] Furthermore, the mass ratio (A / B2) of EVOH (component A) to component B2 is preferably 70 / 30 to 99 / 1, more preferably 70 / 30 to 85 / 15, and particularly preferably 70 / 30 to 80 / 20. By setting the above mass ratio (A / B2) within the aforementioned range, a tendency towards better thermal stability can be observed.

[0109] Moreover, the mass ratio of the above-mentioned B2 component to the above-mentioned B1 component (B2 / B1) is preferably from 0.01 to 10, more preferably from 0.01 to 1, further preferably from 0.02 to 0.8, particularly preferably from 0.03 to 0.5, especially preferably from 0.05 to 0.25, and most preferably from 0.1 to 0.23. By setting the above mass ratio (B2 / B1) within the above range, there is a tendency for more excellent thermal stability.

[0110] Furthermore, the mass ratio of EVOH (A component) to the total mass of the above-mentioned B1 component and the above-mentioned B2 component [A / (B1 + B2)] is preferably from 50 / 50 to 99 / 1, more preferably from 70 / 30 to 85 / 15, and particularly preferably from 70 / 30 to 80 / 20. By setting the above mass ratio [A / (B1 + B2)] within the above range, a tendency for more excellent thermal stability can be observed.

[0111] <Component C>

[0112] As the titanium compound (C) used in this EVOH composition, for example, inorganic titanium compounds and organic titanium compounds can be cited. It should be noted that the titanium compound (C) can be used alone or in combination of two or more kinds, and as long as titanium is contained in the composition. Among them, as the titanium compound (C), an inorganic titanium compound is preferred. The presence and / or content of such titanium is determined, for example, by measurement using ICP mass spectrometry.

[0113] As the above-mentioned inorganic titanium compounds, for example, titanium oxides, titanium hydroxides, titanium chlorides, inorganic salts of titanium, etc. can be cited.

[0114] As the above-mentioned titanium oxides, for example, titanium monoxide, titanium sesquioxide, titanium dioxide, suboxide of titanium, etc. can be cited.

[0115] As the above-mentioned titanium hydroxides, for example, titanium hydroxide(I) and titanium hydroxide can be cited. As the above-mentioned titanium chlorides, for example, titanium trichloride, titanium tetrachloride, etc. can be cited. As the above-mentioned inorganic salts of titanium, for example, titanium phosphate, titanium sulfate, etc. can be cited. Among them, titanium oxides are preferred, titanium dioxide is more preferred, and rutile-type titanium dioxide is particularly preferred.

[0116] As the above-mentioned organic titanium compounds, for example, titanium carboxylates such as titanium acetate, titanium butyrate, titanium stearate, etc. can be cited.

[0117] It should be noted that the above-mentioned titanium compound (C) may exist not only in the form of a titanium compound in the EVOH composition, but also in an ionized state or in the form of a complex interacting with the EVOH resin and / or other ligands.

[0118] The average particle size of the titanium compound (C) is typically 0.001 to 100 μm, preferably 0.01 to 50 μm, and more preferably 0.015 to 20 μm. If the average particle size of the titanium compound (C) is within this range, it tends to exhibit excellent anti-staining properties.

[0119] The content of the titanium compound (C) relative to the EVOH composition, expressed in metal terms, is 0.001 ppm or more and less than 10 ppm by mass. Preferably, it is 0.01 ppm or more and less than 5 ppm by mass, more preferably 0.01 to 3 ppm by mass, further preferably 0.03 to 1 ppm by mass, and particularly preferably 0.05 to 0.5 ppm by mass. By setting the content of the titanium compound (C) within the aforementioned range, color changes caused by thermal degradation during melt molding can be suppressed, resulting in excellent long-term operational performance. Furthermore, by setting the content of the titanium compound (C) to the lower limit or above, the effect of suppressing color changes is excellent; by setting the content to the upper limit or below, thermal decomposition of EVOH (A) is less likely to occur, and coloring is less likely.

[0120] In addition, the content of titanium compound (C) in metal terms is the content of titanium element.

[0121] The content of the above titanium compound (C) in metal terms can be quantified as follows: the EVOH composition is weighed into a platinum crucible, ashed sequentially using a burner and an electric furnace, the ashed material is heated and decomposed with nitric acid and hydrofluoric acid, treated with a mixed acid of dilute nitric acid and dilute hydrofluoric acid and brought to a final volume, and the titanium in the resulting final volume solution is determined by ICP mass spectrometry using an ICP mass spectrometry analyzer (Agilent Technologies, Agilent 8800).

[0122] Typically, EVOH(A) becomes discolored due to thermal degradation. This is believed to be because the thermal degradation of EVOH(A) generates free radicals, which dehydrate the hydroxyl groups of EVOH(A), forming double bonds in the main chain of EVOH(A). This site becomes the reaction initiation point, further promoting dehydration and forming a conjugated polyene structure in the main chain of EVOH(A).

[0123] In contrast, this EVOH composition, by containing a specific trace amount of titanium compound (C), suppresses color changes caused by the thermal degradation of EVOH (A) and exhibits excellent long-term performance. Furthermore, in this EVOH composition, the copolymer (B) component containing ethylene structural units and structural units shown in the above formula (1) exhibits excellent compatibility with EVOH (A), and the multilayer structure and / or molded body containing the EVOH composition exhibits excellent mechanical strength.

[0124] Generally, when a titanium compound (C) is contained in an EVOH composition, it is considered that the EVOH composition is colored by titanium ions. Therefore, it is common technical knowledge for those skilled in the art to avoid using the titanium compound (C).

[0125] However, in the present invention, contrary to such common technical knowledge, it has been found that an EVOH composition with suppressed coloring change caused by thermal deterioration can be obtained when a specific trace amount of the titanium compound (C) is used.

[0126] That is, when titanium is a tetravalent ion, it is stable. It is speculated that even if the content is extremely small, it will be stabilized by coordinating with the double bonds in the main chain of the above-mentioned EVOH (A) and forming chelates, etc., and the formation of the polyene structure will be inhibited.

[0127] <Method for manufacturing an EVOH composition>

[0128] This EVOH composition can be manufactured, for example, by mixing the above-mentioned EVOH (component A), a copolymer (component B) containing an ethylene structural unit and the structural unit represented by the above formula (1), and a titanium compound (component C) by using a known method, such as a dry blending method, a melt mixing method, a solution mixing method, an impregnation method, etc. Among them, it is preferably manufactured by a process of melt-mixing a composition raw material containing these components A to C. In addition, these manufacturing methods can also be arbitrarily combined. It should be noted that for components A to C, they can be mixed at one time, or for example, component A and component B can be first mixed, and then component C can be mixed in the mixture of component A and component B in multiple times of mixing. When component B1 and component B2 are included, component A and component B1 can be first mixed, and then component B2 and component C can be mixed in the mixture of component A and component B1.

[0129] As the above dry blending method, for example, there can be cited: (i) a method of dry blending a mixture of granular components A and B with a titanium compound (C) using a drum mixer, etc.

[0130] As the above melt mixing method, for example, there can be cited: (ii) a method of dry blending a mixture of granular components A and B with a titanium compound (C) and melt-kneading the obtained dry blend; (iii) a method of adding a titanium compound (C) to a mixture of components A to B in a molten state and melt-kneading, etc.

[0131] Examples of the above solution mixing methods include: (iv) preparing a solution using commercially available components A and B, mixing a titanium compound (C) therein, solidifying the solution, and then separating and drying the solution using known methods; (v) during the manufacture of EVOH (A), containing a titanium compound (C) in a solution of ethylene-vinyl ester copolymer before saponification and / or a homogeneous solution of EVOH (A) (water / alcohol solution, etc.), then solidifying the solution, and then separating and drying the solution using known methods.

[0132] Examples of the above impregnation methods include: (vi) contacting a mixture of granular components A and B with an aqueous solution containing titanium compound (C), thereby containing titanium compound (C) in the mixture of components A and B, and then drying it.

[0133] As the above-mentioned aqueous solution containing titanium compound (C), an aqueous solution of titanium compound (C) and / or an aqueous solution in which titanium ions are dissolved by immersing titanium compound (C) in water containing various reagents can be used.

[0134] It should be noted that in the above impregnation method, the content of titanium compound (C) (in metal conversion) can be controlled by the concentration of titanium compound (C) in the aqueous solution of the mixture of components A and B and / or the impregnation temperature, impregnation time, etc.

[0135] The impregnation temperature and time mentioned above are typically 0.5 to 48 hours, preferably 1 to 36 hours, and the impregnation temperature is typically 10 to 40°C, preferably 20 to 35°C.

[0136] As a drying method in the above-mentioned manufacturing methods, various drying methods can be used, including static drying and flow drying. Alternatively, they can be combined.

[0137] In this invention, the different methods described above can be combined as described above. From the perspective of productivity and / or obtaining a composition with more significant effects than those of this invention, melt mixing is preferred, and method (ii) is particularly preferred. Furthermore, when using other thermoplastic resins or other compounding agents described above, compounding can also be performed using conventional methods according to the manufacturing method described above.

[0138] The shape of the EVOH composition obtained by the above manufacturing methods is arbitrary, but granules are preferred.

[0139] The aforementioned granules can be spherical, elliptical, cylindrical, cubic, or cuboid in shape, but are typically elliptical or cylindrical. Regarding their size, from the viewpoint of convenience when used as a molding material, in the case of an elliptical shape, the minor axis is typically 1-10 mm, preferably 2-6 mm, more preferably 2.5-5.5 mm, and the major axis is typically 1.5-30 mm, preferably 3-20 mm, more preferably 3.5-10 mm. In the case of a cylindrical shape, the diameter of the base is typically 1-6 mm, preferably 2-5 mm, and the length is typically 1-6 mm, preferably 2-5 mm.

[0140] In addition, the shape and size of the mixture of granular components A and B used in the above manufacturing methods are preferably the same.

[0141] This EVOH composition exhibits excellent long-term performance, suppressing color changes even when heated during melt molding. The difference between the YI value (yellow index) before heating and the YI value after heating (YI value after heating - YI value before heating) is typically less than 22.5, preferably less than 22, and particularly preferably less than 21. If the difference between the YI value before heating and the YI value after heating is within the aforementioned range, a tendency to suppress color changes determined to be caused by heating can be observed.

[0142] The YI value before heating can be measured as follows: the EVOH composition is pulverized into 1-5 mm square particles, filled into a cylinder with an inner diameter of 32 mm and a height of 30 mm, and compacted. The result is measured using a spectrophotometer SE6000 (manufactured by Nippon Denshoku Kogyo Co., Ltd.).

[0143] In addition, the YI value after heating can be measured as follows: the above-mentioned EVOH composition, which is pulverized into 1-5 mm squares, is heated in an oven under air atmosphere at 150°C for 5 hours, and the substance obtained therefrom is measured using the same method.

[0144] The water content of this EVOH composition is generally 0.01 to 0.5% by mass, preferably 0.05 to 0.35% by mass, and particularly preferably 0.1 to 0.3% by mass.

[0145] It should be noted that the moisture content of this EVOH composition was determined and calculated using the following method.

[0146] Weigh the mass of this EVOH composition before drying (W1) using an electronic balance. Dry it in a hot air dryer at 150°C for 5 hours. Weigh the mass after it has cooled naturally in the dryer for 30 minutes (W2). Calculate the mass using the following formula.

[0147] Moisture content (mass%) = [(W1-W2) / W1] × 100

[0148] The EVOH composition thus obtained is prepared into various shapes such as granules, powders, or liquids, and provided as a material for various molded articles and / or multilayer structures. Furthermore, the EVOH composition exhibits excellent thermal stability and / or resistance to discoloration; therefore, molded articles using the EVOH composition, or multilayer structures having layers using the EVOH composition, have the advantage that even when subjected to repeated heating cycles, quality degradation such as thermal deterioration is minimal. Particularly in the present invention, when provided as a material for melt molding, there is a tendency to obtain the effects of the present invention more effectively, and therefore it is preferred.

[0149] It should be noted that this EVOH composition also includes compositions obtained by mixing resins other than components (A), (B), and (C) used in this EVOH composition.

[0150] When the EVOH composition is in the form of granules, it is preferable to attach a known lubricant to the surface of the granules from the perspective of stabilizing the feedability during melt molding. Examples of lubricants include, for example, higher fatty acids with 12 or more carbon atoms (e.g., lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, oleic acid, etc.), higher fatty acid esters (methyl esters, isopropyl esters, butyl esters, octyl esters, etc. of higher fatty acids), higher fatty acid amides (e.g., saturated higher fatty acid amides such as laurylamide, myristicamide, palmitamide, stearamide, behenicamide, etc.; unsaturated higher fatty acid amides such as oleamide, erucamide, etc.; bis-higher fatty acid amides such as ethylene bis-stearamide, ethylene bis-oleamide, ethylene bis-erucamide, ethylene bis-laurylamide, etc.), low molecular weight polyolefins (e.g., low molecular weight polyethylene with a molecular weight of about 500 to 10,000, or low molecular weight polypropylene, etc., or their acid-modified forms), higher alcohols with 6 or more carbon atoms, ester oligomers, fluorinated vinyl resins, etc. These compounds can be used alone or in combination of two or more. Furthermore, the content of this lubricant is typically 5% by mass or less of the EVOH composition, preferably 1% by mass or less. It should be noted that the lower limit is typically 0% by mass.

[0151] Regarding molded articles provided by this EVOH composition as a molding material, such as single-layer films molded from this EVOH composition, it is also suitable as a recycling composition for applying a thermal process, and therefore can also be used as a layer of recycled materials. Examples include multilayer structures having at least one layer containing such an EVOH composition.

[0152] <Multi-layer structure>

[0153] A multilayer structure (hereinafter referred to as "this multilayer structure") according to one embodiment of the present invention has at least one layer comprising the present EVOH composition. The layer comprising the present EVOH composition (hereinafter, sometimes simply referred to as "this EVOH composition layer") can be further strengthened, protected from moisture, or given other functions by being laminated with other substrates whose main component is a thermoplastic resin other than the present EVOH composition (hereinafter, sometimes the resin used in the substrate is referred to as "substrate resin").

[0154] Examples of the aforementioned base resins include, for instance, polyethylene resins such as linear low-density polyethylene, low-density polyethylene, ultra-low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-propylene (block and random) copolymers, ethylene-α-olefin (α-olefin with 4 to 20 carbon atoms) copolymers, polypropylene resins such as polypropylene, propylene-α-olefin (α-olefin with 4 to 20 carbon atoms) copolymers, polybutene, polypentene, polycyclic olefin resins (polymers in which at least one of the main chain and side chain has a cyclic olefin structure), and / or resins containing these (unmodified) polyolefin resins. Polyolefin resins, broadly defined, include unsaturated carboxylic acid-modified polyolefin resins (those grafted with unsaturated carboxylic acids or their esters), ionomers, ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, ethylene-acrylate copolymers, polyester resins, polyamide resins (including copolyamides), polyvinyl chloride, polyvinylidene chloride, acrylic resins, polystyrene resins, vinyl ester resins, polyester elastomers, polyurethane elastomers, polystyrene elastomers, halogenated polyolefins such as chlorinated polyethylene and chlorinated polypropylene, and aromatic or aliphatic polyketides. These can be used alone or in combination of two or more.

[0155] Among them, polyamide resins, polyolefin resins, polyester resins, and polystyrene resins are preferred as hydrophobic resins, and polyethylene resins, polypropylene resins, polycyclic olefin resins, and their unsaturated carboxylic acid modified polyolefin resins are more preferred as polyolefin resins.

[0156] When the EVOH composition layer is designated as a (a1, a2, ...) and the substrate resin layer is designated as b (b1, b2, ...), the layer configuration of this multilayer structure can be any combination such as a / b, b / a / b, a / b / a, a1 / a2 / b, a / b1 / b2, b2 / b1 / a / b1 / b2, b2 / b1 / a / b1 / a / b1 / b2, etc. Furthermore, when the recycled layer containing the EVOH composition and a mixture of thermoplastic resin other than the EVOH composition, obtained by remelting and molding the ends and / or defective products generated during the manufacturing process of this multilayer structure, is designated as R, it can also be designated as b / R / a, b / R / a / b, b / R / a / R / b, b / a / R / a / b, b / R / a / R / a / R / b, etc. The total number of layers in this multilayer structure is typically 2 to 15, preferably 3 to 10. In the above layer configuration, an adhesive resin layer containing adhesive resin may also be placed between the layers as needed.

[0157] As the aforementioned adhesive resin, any known adhesive resin can be used, and the appropriate type should be selected based on the type of thermoplastic resin used in the substrate resin layer "b". Representative examples of adhesive resins include carboxyl-containing modified polyolefin polymers obtained by chemically bonding unsaturated carboxylic acids or their anhydrides to polyolefin resins through addition reactions and / or grafting reactions. Examples of such carboxyl-containing modified polyolefin polymers include, for instance: maleic anhydride-grafted modified polyethylene, maleic anhydride-grafted modified polypropylene, maleic anhydride-grafted modified ethylene-propylene (block and random) copolymers, maleic anhydride-grafted modified ethylene-ethyl acrylate copolymers, maleic anhydride-grafted modified ethylene-vinyl acetate copolymers, maleic anhydride-modified polycyclic olefin resins, and maleic anhydride-grafted modified polyolefin resins. These can be used alone or in combination of two or more.

[0158] In this multilayer structure, when an adhesive resin layer is used between the EVOH composition layer and the substrate resin layer, since the adhesive resin layer is located on both sides of the EVOH composition layer, it is preferable to use an adhesive resin with excellent hydrophobicity.

[0159] Within a scope that does not impede the spirit of the present invention (e.g., 30% or less by mass relative to the total resin, preferably 10% or less by mass), the aforementioned base resin and adhesive resin may contain conventionally known plasticizers, fillers, clays (montmorillonite, etc.), colorants, antioxidants, antistatic agents, lubricants, nucleating materials, anti-blocking agents, waxes, etc. They may be used alone or in combination of two or more.

[0160] The lamination of the aforementioned EVOH composition layer and the aforementioned substrate resin layer (including the case where an adhesive resin layer is sandwiched) can be performed using known methods. Examples include: methods for melt-extruding and laminating the substrate resin onto a film or sheet of the EVOH composition; methods for melt-extruding and laminating the EVOH composition onto a substrate resin layer; methods for co-extruding the EVOH composition and the substrate resin; methods for dry laminating the EVOH composition (layer) and the substrate resin (layer) using known adhesives such as organotitanium compounds, isocyanate compounds, polyester compounds, and polyurethane compounds; and methods for removing the solvent after coating a solution of the EVOH composition onto the substrate resin. From a cost and / or environmental perspective, it is preferable to manufacture the EVOH composition layer by including a melt-forming process; specifically, a co-extrusion method is preferred.

[0161] This multi-layer structure can be subjected to (heated) stretching treatment as needed. The stretching treatment can be either uniaxial or biaxial stretching. In the case of biaxial stretching, it can be simultaneous or sequential stretching. Alternatively, methods with high stretching ratios, such as roller stretching, tenter frame stretching, tubular stretching, stretch blow molding, and vacuum forming, can also be used. The stretching temperature is near the melting point of the multi-layer structure, typically selected from 40 to 170°C, preferably from around 60 to 160°C. If the stretching temperature is too low, the stretchability is poor; if it is too high, it is difficult to maintain a stable stretching state.

[0162] Furthermore, the stretched multilayer structure can be heat-fixed to impart dimensional stability. Heat fixing can be carried out by known means, such as heat-treating the stretched multilayer structure at a temperature of approximately 80-180°C, preferably 100-165°C, for approximately 2-600 seconds while maintaining tension.

[0163] When the stretched multilayer structure described above is used as a shrink film, in order to impart thermal shrinkage, the aforementioned heat fixation is not performed. For example, the stretched multilayer structure can be cooled and fixed by blowing cold air.

[0164] The thickness of this multilayer structure (including stretched multilayer structures), as well as the thicknesses of the EVOH composition layer, the substrate resin layer, and the adhesive resin layer constituting the multilayer structure, varies depending on the layer composition, the type of substrate resin, the type of adhesive resin, the application and / or packaging form, and the required physical properties. The thickness of this multilayer structure (including stretched multilayer structures) is typically 10–5000 μm, preferably 30–3000 μm, and particularly preferably 50–2000 μm. The thickness of the EVOH composition layer is typically 1–500 μm, preferably 3–300 μm, and particularly preferably 5–200 μm. The thickness of the substrate resin layer is typically 5–3000 μm, preferably 10–2000 μm, and particularly preferably 20–1000 μm. The thickness of the adhesive resin layer is typically 0.5–250 μm, preferably 1–150 μm, and particularly preferably 3–100 μm.

[0165] Furthermore, regarding the thickness ratio of the EVOH composition layer to the substrate resin layer in this multilayer structure (EVOH composition layer / substrate resin layer), when there are multiple layers, the ratio of the thickest layers is typically 1 / 99 to 50 / 50, preferably 5 / 95 to 45 / 55, and particularly preferably 10 / 90 to 40 / 60. Additionally, regarding the thickness ratio of the EVOH composition layer to the adhesive resin layer in this multilayer structure (EVOH composition layer / adhesive resin layer), when there are multiple layers, the ratio of the thickest layers is typically 10 / 90 to 99 / 1, preferably 20 / 80 to 95 / 5, and particularly preferably 50 / 50 to 90 / 10.

[0166] Alternatively, this multi-layered structure can be molded to obtain cup and / or tray-shaped molded bodies. In this case, deep drawing is typically used, specifically including vacuum forming, pneumatic forming, vacuum pneumatic forming, and insert-assisted vacuum pneumatic forming. Furthermore, when obtaining tube and / or bottle-shaped multi-layered containers (laminated structures) from multi-layered preforms (hollow tubular preforms before blow molding), blow molding is used. Specifically, extrusion blow molding (double-headed, mold-moving, preform-shifting, rotary, storage, horizontal preform, etc.), cold preform blow molding, injection blow molding, and biaxial stretch blow molding (extrusion-type cold preform biaxial stretch blow molding, injection-type cold preform biaxial stretch blow molding, injection molding inline biaxial stretch blow molding, etc.) are examples of this. The resulting laminate can be subjected to heat treatment, cooling treatment, rolling treatment, printing treatment, dry lamination treatment, solution or melt coating treatment, bag making, deep drawing treatment, box processing, tube processing, slitting and other processing as needed.

[0167] The containers and / or lids (packaging material containers) including single-layer films formed from the present EVOH composition and / or bags, cups, trays, tubes, bottles, etc. formed from the present multilayer structure are useful as various packaging material containers for condiments such as mayonnaise and sauces, fermented foods such as miso, oily foods such as salad oil, beverages, cosmetics, pharmaceuticals, etc., in addition to general food products.

[0168] Example

[0169] The following examples illustrate the present invention in more detail, but the present invention is not limited to the following examples as long as it does not depart from its spirit. It should be noted that, unless otherwise specified, "parts" and "%" refer to mass standards.

[0170] Before implementing the examples, prepare the following ingredients.

[0171] (A) Ingredients EVOH

[0172] • EVOH (ethylene content 32 mol%, MFR (210℃, load 2160 g) 3.8 g / 10 min, density 1.19 g / cm³) 3 )

[0173] (B) Components : A copolymer comprising ethylene structural units and structural units shown in formula (1) above.

[0174] (Component B1): Ethylene-vinyl carboxylate copolymer and / or ethylene-acrylate copolymer

[0175] • B1-1: EVA (manufactured by Tosoh Corporation, Ultrathene 3B53A, MFR (190℃, load 2160g) 5.7g / 10min, density 0.952g / cm³) 3 )

[0176] •B1-2: EVA (manufactured by Dow-Mitsui Polychemicals Co., Ltd., EVAFLEX EV170, MFR (190℃, load 2160g) 1g / 10min, density 0.960g / cm³) 3 )

[0177] •B1-3: EVA (manufactured by Dow-Mitsui Polychemicals Co., Ltd., EVAFLEX V5961, MFR (190℃, load 2160g) 1.7g / 10min, density 0.930g / cm³) 3 )

[0178] • B1-4: EEA (manufactured by Japan Polyethylene Corporation, Rexpearl EEA A4200, MFR (190℃, load 2160g) 5g / 10min, density 0.934g / cm³) 3 )

[0179] (Component B2): at least one copolymer selected from the group consisting of ethylene-vinyl carboxylate copolymers with polar groups, ethylene-acrylate copolymers with polar groups, ethylene-vinyl carboxylate-maleic anhydride copolymers, and ethylene-acrylate-maleic anhydride copolymers.

[0180] •B2-1: Maleic anhydride modified EVA (MFR (190℃, load 2160g) 16g / 10min, density 0.95g / cm³) 3 )

[0181] •B2-2: Maleic anhydride modified EVA (MFR (190℃, load 2160g) 2g / 10min, density 0.92g / cm³) 3 )

[0182] • B2-3: Ethylene-methyl acrylate-maleic anhydride copolymer (EMA) (manufactured by Japan Polyethylene Corporation, Rexpearl ET ET230X, MFR (190℃, load 2160g) 8.0g / 10min, density 0.943g / cm³) 3 )

[0183] (Component C) Titanium compounds

[0184] Titanium oxide (manufactured by Fujifilm and Wako Pure Chemical Industries, purity 99.0%+)

[0185] <Example 1>

[0186] The mixture was obtained by dry mixing 80 parts of (A), 15 parts of (B1-1), 5 parts of (B2-1), and (C) in a manner where the metal content relative to the total mass of the composition [(A) + (B1-1) + (B2-1)] was 0.1 ppm by mass.

[0187] Next, the mixture is fed into a twin-screw extruder (20mmφ) equipped with a dual-hole die and extruded under the following extrusion conditions. The extruded filament is then cooled and solidified in a water bath.

[0188] Then, after removing water droplets from the surface of the cured filament by blowing air into it, granules of the EVOH composition are obtained by cutting.

[0189] [Extrusion Conditions]

[0190] Extruder set temperature (°C): C1 / C2 / C3 / C4 / C5 / C6=150 / 200 / 210 / 210 / 210 / 210 (Here, C1~C6 represent the heating section of the extruder. Specifically, C represents the barrel section of the extruder, starting from the part closest to the hopper, C1~C6.)

[0191] <Examples 2-7, Comparative Examples 1-3>

[0192] Except that the materials contained in the mixture are those shown in Table 1 below, granules of the EVOH composition were obtained in the same manner as in Example 1.

[0193] For the granules of the obtained EVOH composition, the following indicators were used to evaluate "thermal stability" and "color inhibition".

[0194] [Thermal stability]

[0195] To evaluate the stability during heating, the mass before and after heating was measured as described below, and the residual rate (%) was calculated.

[0196] That is, using a thermogravimetric analyzer (Perkin Elmer, Pyris 1 TGA), the obtained granules (5 mg) were measured under a nitrogen atmosphere, with a gas flow rate of 20 mL / min, a temperature of 230 °C, and a time of 63 minutes. The measured mass before and after heating was then substituted into the following formula to calculate the mass.

[0197] The obtained values ​​are shown in Table 1, which will be described later.

[0198] Residual mass percentage (%) = Mass after heating / Mass before heating × 100

[0199] It can be said that the higher the residual mass, the better the thermal stability. It should be noted that this evaluation measured the difference caused by heating for 63 minutes, but actual manufacturing processes involve much longer thermal histories. Therefore, even if the numerical difference in this evaluation appears small, it will represent a significant difference in performance in practice.

[0200] [Staining Inhibition]

[0201] To evaluate the change in color before and after heating, the YI values ​​before and after heating were measured as described below, and the difference was calculated (YI value after heating - YI value before heating).

[0202] That is, firstly, the obtained granules are crushed into 1-5 mm square pieces, filled into a cylinder with an inner diameter of 32 mm and a height of 30 mm, and compacted. Then, the YI value (before heating) is measured using a spectrophotometer SE6000 (manufactured by Nippon Denshoku Kogyo Co., Ltd.).

[0203] Next, the YI value (YI value after heating) of the pulverized material obtained by heating the above-mentioned pulverized material in an oven at 150°C for 5 hours under air atmosphere was also measured in the same way.

[0204] The obtained values ​​are shown in Table 1, which will be described later.

[0205] It can be said that the smaller the difference in YI value before and after heating, the more the coloring caused by heating is suppressed.

[0206] [Table 1]

[0207]

[0208] It can be seen that, compared with Comparative Example 1, Examples 1-3, which contain a specific amount of titanium compound (C), have the same mass residue rate, but the YI value decreases after heating, and the coloring caused by heating is suppressed. Furthermore, it can be seen that, compared with Comparative Example 3, Example 7 also has the same mass residue rate, but the coloring caused by heating is also suppressed.

[0209] Furthermore, it is known that, compared with Examples 1 to 3, Comparative Example 2, which contains more than the specific amount of titanium compound (C) in this invention, has a lower mass residue and poorer thermal stability.

[0210] In this way, the EVOH composition can reduce color changes caused by heating while maintaining thermal stability.

[0211] The above embodiments illustrate specific aspects of the present invention, but these embodiments are merely illustrative and not intended to be limiting. It is understood that various modifications that will be apparent to those skilled in the art are within the scope of the present invention.

[0212] Industrial availability

[0213] This composition exhibits excellent thermal stability and resistance to heat-induced coloring. Therefore, molded articles formed from this composition and / or multilayer structures having layers containing this composition are useful as materials for various packaging containers.

Claims

1. A composition comprising an ethylene-vinyl alcohol copolymer A, a copolymer B, a titanium compound C, the copolymer B comprising an ethylene structural unit and a structural unit represented by the following formula (1), the content of the titanium compound C in the composition is 0.001 mass ppm or more and less than 10 mass ppm in terms of metal, In formula (1), R1is alkyloxycarbonyl (-COOR A ) or acyloxy (-OOCR A ), and R A represents a hydrogen atom or an aliphatic hydrocarbon group having 1 to 20 carbon atoms.

2. The composition of claim 1, wherein, R in the formula (1) is a hydrogen atom or an aliphatic hydrocarbon group having 1 to 4 carbon atoms. A R in the formula (1) is a hydrogen atom or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.

3. The composition of claim 1, wherein, the copolymer B comprises an ethylene-vinyl carboxylate copolymer and / or an ethylene-acrylate copolymer Bl.

4. The composition of claim 1, wherein, the copolymer B comprises: an ethylene-vinyl carboxylate copolymer and / or an ethylene-acrylate copolymer Bl; and at least one copolymer B2 selected from the group consisting of an ethylene-vinyl carboxylate copolymer having a polar group, an ethylene-acrylate copolymer having a polar group, an ethylene-vinyl carboxylate-maleic anhydride copolymer, and an ethylene-acrylate-maleic anhydride copolymer.

5. The composition of claim 4, wherein, the polar group in the ethylene-vinyl carboxylate copolymer having a polar group is a carboxyl group or a carbonyloxy carbonyl group.

6. The composition of claim 4, wherein, the copolymer B is an ethylene-vinyl carboxylate copolymer having a polar group and / or an ethylene-acrylate copolymer having a polar group, and at least one of the polar groups is a carboxyl group.

7. The composition of claim 5, wherein, the carbonyloxy carbonyl group in the carbonyloxy carbonyl group is maleic anhydride.

8. The composition of claim 1, wherein, the content of the titanium compound C in the composition is 0.001 mass ppm or more and 5 mass ppm or less.

9. The composition of claim 1, wherein, the mass ratio A / B of the ethylene-vinyl alcohol copolymer A with respect to the copolymer B is 70 / 30 to 99 / 1.

10. The composition of claim 1, wherein, the mass ratio A / B of the ethylene-vinyl alcohol copolymer A with respect to the copolymer B is 70 / 30 to 85 / 15.

11. The composition of claim 4, wherein, the mass ratio B2 / B1 of the copolymer B2 with respect to the copolymer Bl is 0.01 to 10.

12. The composition of claim 4, wherein, the mass ratio [A / (Bl+B2)] of the ethylene-vinyl alcohol copolymer A with respect to the total mass of the copolymer Bl and the copolymer B2 is 50 / 50 to 99 / 1.

13. A composition for recycling, wherein, the composition according to any one of claims 1 to 12 for recycling.

14. A recycled material layer comprising the composition according to any one of claims 1 to 12.

15. A multilayer structure having a layer comprising the composition according to any one of claims 1 to 12.

16. The multilayer structure according to claim 15, further having an adhesive resin layer.

17. A molded body molded from the multilayer structure according to claim 15.

18. A packaging material container molded from the multilayer structure according to claim 15.

19. A method for producing a composition, which is the method for producing the composition according to claim 1, having a step of mixing the ethylene-vinyl alcohol copolymer A, the copolymer B, and the titanium compound C.

20. A method for producing a composition, which is the method for producing the composition according to claim 4, having a step of mixing the ethylene-vinyl alcohol copolymer A, the copolymer Bl, the copolymer B2, and the titanium compound C.

21. A method for producing a multilayer structure, comprising: a step of producing a composition by the method for producing a composition according to claim 19 or 20; and a step of forming a layer comprising the composition obtained by the step as at least one layer of a multilayer structure.

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