Resin composition and molded articles containing the same, and modifier for modified ethylene-vinyl alcohol resins containing aliphatic polyester units.

Abstract

To provide a resin composition which is excellent in wettability, and improves antifogging property, antistatic property, antifouling property and coating property accompanying the same.SOLUTION: A resin composition contains a modified ethylene-vinyl alcohol-based resin (A) containing an aliphatic polyester unit, and a hydrophilic organic compound (B), wherein an SP value of the hydrophilic organic compound (B) is larger than 13.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a resin composition containing a modified ethylene-vinyl alcohol resin (A) containing an aliphatic polyester unit and a hydrophilic organic compound (B), wherein the SP value of the hydrophilic organic compound (B) is greater than 13, a molded product containing the same, and a modifier for a modified ethylene-vinyl alcohol resin containing an aliphatic polyester unit.

Background Art

[0002] Ethylene-vinyl alcohol resins have very strong intermolecular forces due to hydrogen bonding between hydroxyl groups present in the polymer side chains. Therefore, they have high crystallinity and high intermolecular forces even in the amorphous part, so gas molecules and the like hardly pass through a film made of an ethylene-vinyl alcohol resin, and a film made of an ethylene-vinyl alcohol resin exhibits excellent gas barrier properties.

[0003] However, ethylene-vinyl alcohol resins are hard and brittle resins and have the drawback of lacking flexibility. Therefore, when used as packaging materials or molding materials, when repeatedly bent and used, cracks and pinholes occur due to bending fatigue and the like, and there are problems such as the inability to maintain their excellent performance.

[0004] As a means for solving such problems, a modified ethylene-vinyl alcohol resin containing an aliphatic polyester unit in the hydroxyl group of an ethylene-vinyl alcohol resin has been proposed by ring-opening polymerization reaction of lactones (for example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, while the modified ethylene-vinyl alcohol resin described in Patent Document 1 is more flexible than the unmodified ethylene-vinyl alcohol resin, the addition of aliphatic polyester increases the number of hydrophobic groups, which reduces the wettability of molded products using it. Consequently, this leads to problems such as reduced antifogging, antistatic, antifouling, and coating properties.

[0007] The present invention aims to provide a resin composition that exhibits excellent wettability, and consequently, improved anti-fogging, antistatic, anti-fouling, and coating properties. [Means for solving the problem]

[0008] However, in view of these circumstances, the inventors have conducted extensive research and have found that the problems of the present invention can be solved by a resin composition comprising a modified ethylene-vinyl alcohol resin (A) containing aliphatic polyester units and a hydrophilic organic compound (B), wherein the SP value of the hydrophilic organic compound (B) is greater than 13.

[0009] In other words, the present invention has the following aspects. [1] A resin composition comprising a modified ethylene-vinyl alcohol resin (A) containing aliphatic polyester units and a hydrophilic organic compound (B), wherein the SP value of the hydrophilic organic compound (B) is greater than 13. [2] The resin composition according to [1], wherein the hydrophilic organic compound (B) is a hydrophilic polyhydric alcohol. [3] The resin composition according to [1] or [2], wherein the SP value of the hydrophilic organic compound (B) is greater than 18. [4] The resin composition according to any one of [1] to [3], wherein the content of the hydrophilic organic compound (B) is 0.1 to 30 parts by weight per 100 parts by weight of the modified ethylene-vinyl alcohol resin (A) containing the aliphatic polyester units. [5] A molded article containing the resin composition described in any of [1] to [4]. [6] A modifier for modified ethylene-vinyl alcohol resins containing aliphatic polyester units, which includes a hydrophilic organic compound with an SP value greater than 13.

[0010] In the following, "ethylene-vinyl alcohol resin" may be abbreviated as "EVOH," and "modified EVOH containing aliphatic polyester units" may be abbreviated as "aliphatic polyester modified EVOH" or "modified EVOH." [Effects of the Invention]

[0011] The present invention can provide a resin composition with improved wettability and a molded article containing the resin composition.

[0012] Furthermore, by incorporating the modifier for modified EVOH of the present invention into modified EVOH(A), it is possible to provide modified EVOH(A) with the above-mentioned excellent physical properties. [Modes for carrying out the invention]

[0013] The configuration of the present invention will be described in detail below, but these are merely examples of preferred embodiments. The present invention is not limited to the embodiments described below. In this invention, "film" conceptually encompasses sheets, films, and tapes.

[0014] First, the resin composition of the present invention contains a modified EVOH (A) containing aliphatic polyester units and a hydrophilic organic compound (B), which will be explained in detail in separate sections below.

[0015] <Aliphatic polyester-modified EVOH(A)> The above aliphatic polyester-modified EVOH(A) is a modified EVOH containing aliphatic polyester units. It is preferable that the aliphatic polyester units are bonded to the side chains of EVOH, as this facilitates the imparting of flexibility. Examples of such modified EVOH (A) preferably include resins obtained by grafting an aliphatic polyester onto a hydroxyl group in the side chain of EVOH. The formation of the aliphatic polyester by such a graft reaction uses the hydroxyl group of EVOH as the starting end.

[0016] The above-mentioned EVOH is usually a resin obtained by saponifying an ethylene-vinyl ester copolymer, which is a copolymer of ethylene and a vinyl ester monomer, and is a water-insoluble thermoplastic resin.

[0017] As the polymerization method of the above-mentioned ethylene and vinyl ester monomer, any known polymerization method, for example, solution polymerization, suspension polymerization, emulsion polymerization can be used, and generally solution polymerization using methanol as a solvent is used. And the saponification of the obtained ethylene-vinyl ester copolymer can also be carried out by a known method.

[0018] The EVOH produced in this way mainly consists of structural units derived from ethylene and vinyl alcohol structural units, and usually contains a small amount of vinyl ester structural units remaining without being saponified.

[0019] As the above-mentioned vinyl ester monomer, vinyl acetate is typically used from the viewpoints of market availability and impurity treatment efficiency during production. Other vinyl ester monomers include, for example, aliphatic vinyl esters such as vinyl formate, vinyl propionate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl versatate, and aromatic vinyl esters such as vinyl benzoate. Usually, aliphatic vinyl esters having 3 to 20 carbon atoms, preferably 4 to 10 carbon atoms, particularly preferably 4 to 7 carbon atoms can be used. These can be used alone or in combination of two or more.

[0020] The ethylene structural unit content in the above-mentioned EVOH can be controlled by the pressure of the ethylene during copolymerization of the vinyl ester monomer and ethylene, and is typically 20-60 mol%, preferably 25-50 mol%, and particularly preferably 30-45 mol%. If the content is too low, melt moldability tends to decrease. Conversely, if it is too high, gas barrier properties tend to decrease. The content of such ethylene structural units can be measured in accordance with ISO 14663.

[0021] Furthermore, the degree of saponification of the vinyl ester component in the above-mentioned EVOH can be controlled by the amount of saponification catalyst (usually an alkaline catalyst such as sodium hydroxide is used) used to saponify the ethylene-vinyl ester copolymer, the temperature, the time, etc., and is usually 90-100 mol%, preferably 95-100 mol%, and particularly preferably 99-100 mol%. If the degree of saponification is too low, the gas barrier properties, thermal stability, moisture resistance, etc. tend to decrease. The degree of saponification of such EVOH can be measured according to JIS K6726 (provided that EVOH is used as a solution homogeneously dissolved in water / methanol solvent).

[0022] Furthermore, the above-mentioned EVOH may further contain structural units derived from the following comonomers, within a range that does not inhibit the effects of the present invention (for example, 10 mol% or less of EVOH). The above comonomers include olefins such as propylene, 1-butene, and isobutene; hydroxyl group-containing α-olefins such as 3-buten-1-ol, 3-buten-1,2-diol, 4-penten-1-ol, and 5-hexen-1,2-diol, and their esterified and acylated derivatives; hydroxyalkylvinylidenes such as 2-methylenepropane-1,3-diol and 3-methylenepentane-1,5-diol; 1,3-diacetoxy-2-methylenepropane, 1,3-dipropionyloxy-2-methylenepropane, and 1,3-dibutyryloxy Hydroxyalkylvinylidene diacetates such as -2-methylenepropane; unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, (anhydride) phthalic acid, (anhydride) maleic acid, (anhydride) itaconic acid, or their salts, or mono or dialkyl esters with 1 to 18 carbon atoms in the alkyl group; acrylamide, N-alkylacrylamide with 1 to 18 carbon atoms in the alkyl group, N,N-dimethylacrylamide, 2-acrylamidopropanesulfonic acid or its salts, acrylamidopropyldimethylamine or its salts or its quaternary salts, etc. Acrylamides; methacrylamide, N-alkylmethacrylamide with 1 to 18 carbon atoms in the alkyl group, N,N-dimethylmethacrylamide, 2-methacrylamidepropanesulfonic acid or its salts, methacrylamidopropyldimethylamine or its salts or its quaternary salts, and other methacrylamides; N-vinylamides such as N-vinylpyrrolidone, N-vinylformamide, N-vinylacetamide; vinyl cyanides such as acrylonitrile, methacrylnitrile; alkyl vinyl ethers with 1 to 18 carbon atoms in the alkyl group, hydr Examples include vinyl ethers such as roxyalkyl vinyl ethers and alkoxyalkyl vinyl ethers; vinyl halogenated compounds such as vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, and vinyl bromide; vinyl silanes such as trimethoxyvinylsilane; allyl halogenated compounds such as allyl acetate and allyl chloride; allyl alcohols such as allyl alcohol and dimethoxyallyl alcohol; and comonomers such as trimethyl-(3-acrylamido-3-dimethylpropyl)-ammonium chloride and acrylamide-2-methylpropanesulfonic acid.These can be used individually or in combination of two or more types.

[0023] In particular, EVOH having a primary hydroxyl group in the side chain is preferred because it exhibits good secondary moldability in processes such as stretching and vacuum / pressure forming, and among these, EVOH having a 1,2-diol structure in the side chain is preferred.

[0024] Furthermore, the EVOH used in the present invention may be a "post-modified" product, such as urethane, acetal, cyanoethylated, oxyalkylene, or acylated product.

[0025] Furthermore, the EVOH used in the present invention may be a mixture with other different EVOHs, and examples of such other EVOHs include those with different degrees of saponification, different degrees of polymerization, different copolymer components, and so on.

[0026] Next, a method for obtaining aliphatic polyester-modified EVOH (A) used in the present invention using the above-mentioned EVOH will be explained. Methods for modifying EVOH include (1) a ring-opening polymerization of lactones in the presence of EVOH, and (2) a method in which aliphatic polyesters or lactones are first subjected to ring-opening polymerization or condensation polymerization to obtain a polyester having a carboxyl group at the terminal, and then this polyester having a carboxyl group at the terminal reacts with EVOH.

[0027] In particular, the method of ring-opening polymerization of lactones in the presence of EVOH is preferable because it allows for the easy acquisition of a resin in which aliphatic polyesters are grafted onto EVOH in a single reaction, thus requiring fewer steps and being simpler than methods in which aliphatic polyesters are first produced by ring-opening polymerization or condensation polymerization and then reacted with EVOH.

[0028] The lactones mentioned above are preferably lactones in which the number of carbon atoms constituting the ring that forms an aliphatic polyester by ring-opening polymerization is 3 to 10. When such lactones do not have substituents, they are represented by the following general formula (1).

[0029] [ka]

[0030] In the above formula (1), n ​​is an integer from 2 to 9, preferably n is 4 to 5. Also, the alkylene chain -(CH2) in the above formula (1) n - Any of the carbon atoms may have at least one substituent such as a lower alkyl group, lower alkoxy group, cycloalkyl group, phenyl group, or aralkyl group having approximately 1 to 8 carbon atoms.

[0031] Examples of such lactones include β-propion lactones, γ-butyrolactones, ε-caprolactones, and δ-valerolactones.

[0032] Examples of the above-mentioned β-propion lactones include β-propion lactone and dimethylpropion lactone.

[0033] Examples of the above-mentioned γ-butyrolactones include butyrolactone, γ-valerolactone, γ-caprolactone, γ-capryloractone, γ-laurolactone, γ-palmitractone, γ-stearolactone, crotonolactone, α-angelicalactone, and β-angelicalactone.

[0034] Examples of the above-mentioned ε-caprolactones include monoalkyl-ε-caprolactones such as ε-caprolactone, monomethyl-ε-caprolactone, monoethyl-ε-caprolactone, monodecyl-ε-caprolactone, monopropyl-ε-caprolactone, and monodecyl-ε-caprolactone; dialkyl-ε-caprolactones in which two alkyl groups are substituted on carbon atoms other than the ε position; trialkyl-ε-caprolactones in which three alkyl groups are substituted on carbon atoms other than the ε position; alkoxy-ε-caprolactones such as ethoxy-ε-caprolactone; cycloalkyl-lactones such as cyclohexyl-ε-caprolactone; aralkyl-ε-caprolactones such as benzyl-ε-caprolactone; and aryl-ε-caprolactones such as phenyl-ε-caprolactone.

[0035] Examples of the δ-valerolactones mentioned above include 5-valerolactone, 3-methyl-5-valerolactone, 3,3-dimethyl-5-valerolactone, 2-methyl-5-valerolactone, and 3-ethyl-5-valerolactone.

[0036] These lactones can be used individually or in combination of two or more.

[0037] Among these, ε-caprolactones and δ-valerolactones are particularly preferred, with ε-caprolactone being especially preferred due to its low cost and easy availability.

[0038] Furthermore, in reactions involving ring-opening polymerization, it is preferable to add a conventionally known ring-opening polymerization catalyst. Examples of ring-opening polymerization catalysts include titanium compounds and tin compounds. Specifically, examples include titanium alkoxides such as tetra-n-butoxytitanium, tetraisobutoxytitanium, and tetraisopropoxytitanium; tin alkoxides such as dibutyldibutoxytin; and tin ester compounds such as tin 2-ethylhexanoate and dibutyltin diacetate. Among these, tetra-n-butoxytitanium and tin 2-ethylhexanoate are preferred because they are inexpensive and readily available.

[0039] Furthermore, the above reaction can also be carried out in a heated and melted state in a kneading machine such as a single-screw or twin-screw extruder, Banbury mixer, kneader, or brabender.

[0040] Furthermore, the reaction time and temperature in ring-opening polymerization are not particularly limited and can be selected as appropriate, but it is preferable to carry out the reaction at 50 to 250°C for 10 seconds to 24 hours with stirring, and more preferably at 150 to 230°C for 50 seconds to 10 hours with stirring. If the reaction time is too short or the reaction temperature is too low, the reaction rate will decrease, and unreacted compounds tend to bleed out of the molded product, causing deterioration of the surface appearance. If the reaction time is too long or the reaction temperature is too high, crosslinking will occur between the modified EVOHs, and defects in the appearance of the molded product, such as fish eyes, tend to occur.

[0041] In the aliphatic polyester-modified EVOH(A) obtained in this manner, the content of EVOH units forming the main chain of the modified EVOH(A) is usually 40 to 99% by weight, preferably 45 to 95% by weight, and particularly preferably 50 to 90% by weight. The content of aliphatic polyester units bonded as side chains to the EVOH units of the main chain is usually 1 to 60% by weight, preferably 5 to 55% by weight, and particularly preferably 10 to 50% by weight. If the amount of EVOH units is too high, the thermal stability decreases, and the effects of the present invention tend not to be obtained. On the other hand, if the amount of EVOH units is too low, the dispersibility of the hydrophilic organic compound (B) tends to decrease. The content of EVOH units and aliphatic polyester units in the aliphatic polyester-modified EVOH(A) described above is: 1 It can be calculated from the H-NMR measurement results.

[0042] Furthermore, the number-average molecular weight (in terms of standard polystyrene measured by GPC) of the above-mentioned aliphatic polyester-modified EVOH(A) is typically 5,000 to 300,000, preferably 10,000 to 200,000, and particularly preferably 10,000 to 100,000. If the number-average molecular weight of the above-mentioned modified EVOH(A) is too high, its melt viscosity tends to be too high, reducing the dispersibility of the hydrophilic organic compound (B). On the other hand, if the number-average molecular weight of the above-mentioned modified EVOH(A) is too low, its melt viscosity tends to be too low, making stable melt molding difficult. The number-average molecular weight of the above-mentioned modified EVOH(A) can be calculated from the GPC measurement results.

[0043] Furthermore, the modification rate of the aliphatic polyester in the above-mentioned aliphatic polyester-modified EVOH(A) (hereinafter simply referred to as "modification rate") is usually 0.1 to 30 mol%, more preferably 1 to 25 mol%, and particularly preferably 5 to 20 mol%. If the above modification rate is too low, the hydrophilic organic compound (B) will not easily migrate to the surface of the molded product, and the effects of the present invention tend not to be obtained. On the other hand, if the above modification rate is too high, the adhesiveness will be strong and blocking of the molded product tends to occur. Note that the above modification rate is 1 It can be calculated from the H-NMR measurement results.

[0044] Furthermore, the average chain length of aliphatic polyester units in the above-mentioned aliphatic polyester-modified EVOH(A) is usually 1 to 15 units, preferably 1 to 10 units, and particularly preferably 1 to 8 units. If the average chain length of the above-mentioned aliphatic polyester units is too long, the adhesiveness will be strong and blocking of the molded product will be more likely to occur. Note that the average chain length of the above-mentioned aliphatic polyester units is 1 It can be calculated from the H-NMR measurement results.

[0045] Specifically, under the following conditions 1 By measuring with 1H-NMR, the degree of modification of the aliphatic polyester and the average chain length of the aliphatic polyester can be calculated in aliphatic polyester-modified EVOH(A).

[0046] (a)1 H-NMR measurement conditions Internal standard: Tetramethylsilane Solvent: d6-DMSO Measured polymer concentration: 5% by weight (0.1g sample, 2mL solvent) Measurement temperature: 50℃ (323K) Irradiation pulse: 45° pulse Pulse interval: 10 sec Total number of times: 16

[0047] (b) Assignment of resonance absorption peaks (I) 0.8~0.9 ppm: -CH3 at the aliphatic polyester-modified EVOH terminus (II) 1.0~1.9 ppm: -CH2- of the aliphatic polyester modified EVOH main chain, and adjacent -CH2- of the aliphatic polyester (III) 2.0 ppm: -CH3 residual acetyl group of aliphatic polyester-modified EVOH (IV) 2.1~2.3 ppm: -CH2- adjacent to the carboxyl group of aliphatic polyester (V) 3.3~4.0 ppm: -CH- adjacent to the -OH of aliphatic polyester-modified EVOH, and -CH2- adjacent to the -OH of aliphatic polyester (VI) 4.0~4.7 ppm: Aliphatic polyester-modified EVOH, the -OH group of the aliphatic polyester, and the -CH2- group adjacent to the ester bond of the aliphatic polyester.

[0048] (c) Calculation of the denaturation rate and average chain length of aliphatic polyesters Using the integral values ​​of the resonance absorption peaks in (I) to (VI) above, the following system of equations (i) to (vi) was established, and the amount of modified groups C (moles) and the average chain length n (units) of the aliphatic polyester were calculated from the solution to the system of equations. Furthermore, the modification rate X (mol%) of the aliphatic polyester was calculated from equation (vii). Equation (i): 3 × M = [Integral value of peak (I)] Equation (ii): (2×M)+(2×A)+(4×E)+(2×O)+(6×n+2)×C=[Integral value of peak(II)] Equation (iii): 3 × A = [Integral value of peak (III)] Equation (iv): 2 × n × C = [Integral value of peak (IV)] Equation (v): O + (2 × C) = [Integral value of peak (V)] Equation (vi): O + (2 × n - 1) × C = [Integral value of peak (VI)] Equation (vii): X = C / (M + A + O + C + E) × 100 Here, M, A, O, C, n, E, and X represent the following values: M: Amount of terminal methyl groups (moles) in aliphatic polyester-modified EVOH A: Amount of acetyl groups (moles) in aliphatic polyester-modified EVOH O: Amount of hydroxyl groups (moles) in aliphatic polyester-modified EVOH C: Amount of aliphatic polyester-modified group (moles) in aliphatic polyester-modified EVOH n: Average chain length of aliphatic polyester (number of chains) E: Amount of ethylene groups (moles) in aliphatic polyester-modified EVOH X: Degeneration rate (mol%) of aliphatic polyester-modified EVOH

[0049] Furthermore, the glass transition temperature (Tg) of the aliphatic polyester-modified EVOH(A) used in the present invention is typically -50 to 60°C, preferably -30 to 45°C, and particularly preferably -10 to 35°C. If the glass transition temperature is too low, the molded product tends to block easily, while if the glass transition temperature is too high, the effects of the present invention tend not to be obtained. The above glass transition temperature can be measured using a differential scanning calorimeter.

[0050] Specifically, the glass transition temperature of aliphatic polyester-modified EVOH(A) can be calculated by measuring it using a differential scanning calorimeter under the following conditions. (a) Conditioning of the test specimens: The specimens were melted at 230°C for 1 minute, and then cooled to -30°C at a cooling rate of 10°C / min. (b) Analysis of glass transition temperature: The sample cooled in (a) was heated to 230°C at a heating rate of 10°C / min. (c) Calculation of glass transition temperature: From the DSC curve obtained in (b), the temperature at the midpoint of the step-like transition portion of the glass transition was calculated as the glass transition temperature.

[0051] Furthermore, the melt flow rate (MFR) of the aliphatic polyester-modified EVOH (A) is typically 0.5 to 100 g / 10 min, preferably 1 to 50 g / 10 min, and particularly preferably 3 to 35 g / 10 min. If the MFR is too high, the melt viscosity of the modified EVOH (A) tends to be too low, making stable melt molding difficult. If the MFR is too low, the melt viscosity of the modified EVOH (A) tends to be too high, reducing the dispersibility of the hydrophilic organic compound (B). Such MFR serves as an indicator of the degree of polymerization of EVOH, which forms the main chain of modified EVOH(A), and can be adjusted by the amount of polymerization initiator and solvent used when copolymerizing the monomers.

[0052] <Hydrophilic organic compound (B)> Next, we will describe the hydrophilic organic compound (B) used in conjunction with the aliphatic polyester-modified EVOH (A) described above.

[0053] The hydrophilic organic compound (B) used in the present invention is a hydrophilic organic compound with an SP value greater than 13. A hydrophilic organic compound refers to an organic compound that dissolves in water. Specifically, it is an organic compound having functional groups such as hydroxyl groups, carboxyl groups, sulfonic acid groups, phosphonic acid groups, amino groups, amide groups, and quaternary ammonium groups in its molecule. The term "soluble in water" above means that the solubility in water at 25°C is 5g / 100mL or higher.

[0054] The SP value of the hydrophilic organic compound (B) is greater than 13, preferably greater than 15, more preferably greater than 18, and particularly preferably greater than 20. The upper limit of the SP value is usually 35. If the SP value is 13 or less, the wettability improvement effect of modified EVOH (A) cannot be obtained.

[0055] The SP value is a parameter that indicates the compatibility of compounds, and compounds with similar SP values ​​are considered to have higher compatibility. The SP value of modified EVOH (A) is around 11-12 according to Hoy's equation, while the SP value of the hydrophilic organic compound (B) is 13 or higher. Therefore, there is a difference in SP values ​​between modified EVOH (A) and hydrophilic organic compound (B), and the larger this difference, the lower the compatibility with modified EVOH (A), and hydrophilic organic compound (B) tends to phase separate from modified EVOH (disperse in modified EVOH).

[0056] When compounding organic compounds with modified EVOH (A), it is desirable for them to mix uniformly, so compounds with similar SP values ​​are usually selected. However, unexpectedly, by using a hydrophilic organic compound (B) with a different SP value from modified EVOH (A), the phase-separated hydrophilic organic compound (B) migrated to the EVOH surface and segregated on the surface, and it is thought that the wettability was improved due to the hydrophilicity derived from the hydrophilic organic compound (B).

[0057] The SP value in this invention is calculated using Hoy's formula, and the unit of the SP value is (cal / cm²). 3 ) 1 / 2 That is the case. The calculation method specifically uses the calculation software "Hoy Solubility Palameter Calculation (manufactured by Computer Chemistry Consultancy)".

[0058] Examples of hydrophilic organic compounds (B) include hydrophilic polyhydric alcohols such as pentaerythritol (SP value: 21), meso-erythritol (SP value: 19), D-sorbitol (SP value: 16), D-mannitol (SP value: 16), dulcitol (SP value: 16), and myo-inositol (SP value: 32); hydrophilic organic compounds containing hydroxyl groups such as N-(2-aminoethyl)ethanolamine (SP value: 14), 4-hydroxymethylimidazole (SP value: 17), and 2-hydroxymethylimidazole (SP value: 17); and N-methylacetamide (SP value: 15) and imidazole (SP value: 14). These can be used individually or in combination of two or more.

[0059] Wettability is improved by the formation of hydrogen bonds between water molecules and hydroxyl groups on the substrate surface. Therefore, since wettability is improved by the presence of compounds having hydroxyl groups on the surface, it is preferable to use hydrophilic polyhydric alcohols or hydrophilic organic compounds containing oxygen atoms among the hydrophilic organic compounds (B) mentioned above, and more preferably hydrophilic polyhydric alcohols.

[0060] <Resin composition> The resin composition of the present invention comprises a modified EVOH (A) containing aliphatic polyester units and a hydrophilic organic compound (B) with an SP value greater than 13.

[0061] The hydrophilic organic compound (B) is preferably present in an amount of 0.1 parts by weight or more, more preferably 0.3 parts by weight or more, even more preferably 0.5 parts by weight or more, and especially preferably 1 part by weight or more, per 100 parts by weight of modified EVOH (A). Furthermore, the upper limit of the content is preferably 30 parts by weight or less, more preferably 25 parts by weight or less, even more preferably 20 parts by weight or less, and especially preferably 15 parts by weight or less. If the content of hydrophilic organic compound (B) is too low, the wettability tends not to improve. If the content of hydrophilic organic compound (B) is too high, it tends to degrade the physical properties of modified EVOH.

[0062] The resin composition of the present invention, by combining a modified EVOH (A) containing aliphatic polyester units with a hydrophilic organic compound (B) having an SP value greater than 13, can surprisingly significantly improve the hydrophilicity of the modified EVOH (A).

[0063] The resin composition of the present invention may contain thermoplastic resins other than modified EVOH(A) in a range that does not impair the effects of the present invention (for example, usually 30% by weight or less, preferably 20% by weight or less, and particularly preferably 10% by weight or less of the resin composition).

[0064] Furthermore, the resin composition may contain additives commonly used in EVOH, such as heat stabilizers, antioxidants, antistatic agents, colorants, ultraviolet absorbers, lubricants, plasticizers, light stabilizers, surfactants, antibacterial agents, drying agents, antiblocking agents, flame retardants, crosslinking agents, curing agents, foaming agents, nucleating agents, antifogging agents, biodegradable additives, silane coupling agents, oxygen absorbers, etc., within a range that does not impair the effects of the present invention (for example, 5% by weight or less of the total resin composition). These additives may be used individually or in combination of two or more.

[0065] Examples of the above-mentioned heat stabilizers include organic acids such as acetic acid, propionic acid, butyric acid, lauric acid, stearic acid, oleic acid, and behenic acid, or their alkali metal salts (sodium, potassium, etc.), alkaline earth metal salts (calcium, magnesium, etc.), and zinc salts, for the purpose of improving various physical properties such as thermal stability during melt molding; or inorganic acids such as sulfuric acid, sulfurous acid, carbonic acid, phosphoric acid, and boric acid, or additives such as their alkali metal salts (sodium, potassium, etc.), alkaline earth metal salts (calcium, magnesium, etc.), and zinc salts. Among these, acetic acid, boric acid, boron compounds including their salts, acetates, and phosphates are preferably used.

[0066] <Preparation of resin composition> The resin composition of the present invention can be obtained by mixing and preparing optional components as needed.

[0067] There are no particular limitations on the above mixing method. Generally, methods are used in which the materials are mixed by melt mixing, solution mixing, etc., and then molded into an easy-to-handle shape such as pellets to prepare a resin composition. From the viewpoint of productivity, melt mixing is preferred.

[0068] The above melt-mixing method can be performed by dry-blending each component and then melting and mixing them, or by using known kneading equipment such as a kneader-ruder, extruder, mixing roll, Banbury mixer, or plast mill. Industrially, it is generally preferable to use a single-screw or twin-screw extruder, and it is also preferable to provide a vent suction device, gear pump device, screen device, etc., as needed.

[0069] The above melt-mixing temperature is typically in the range of 50 to 250°C as the set temperature for the extruder and die, preferably 100 to 240°C, and particularly preferably 150 to 230°C. If the temperature is too low, the resin tends to remain in an unmelted state, and the processing state tends to become unstable. If the temperature is too high, the resin composition tends to degrade due to heat, and the quality of the resulting molded product tends to decrease.

[0070] Furthermore, for example, methods for adding additives such as acetic acid, boron compounds, acetates, and phosphates to a resin composition include: v) a method of contacting the resin composition with an aqueous solution of the additive to incorporate the additive into the resin composition and then drying it; vi) a method of mixing the resin composition and the additive together and then melt-kneading them in an extruder or the like.

[0071] Furthermore, it is possible to blend two or more different types of denatured EVOH, or to blend denatured EVOH with regular EVOH.

[0072] <Uses of resin compositions> The resin composition obtained in this way can be molded into molded products such as films, sheets, cups, and bottles by melt molding. The main melt molding methods used are extrusion molding (T-die extrusion, inflation extrusion, blow molding, melt spinning, mold extrusion, etc.) and injection molding. The melt molding temperature is usually selected from the range of 150 to 300°C.

[0073] Molded products can be used as is for various purposes, but they are usually laminated with other substrates to form laminates in order to further increase strength or add other functions. Thermoplastic resins are useful as other substrates for this purpose. Examples of thermoplastic resins include polyethylenes such as linear low-density polyethylene, low-density polyethylene, ultra-low-density polyethylene, medium-density polyethylene, and high-density polyethylene; polypropylene; ethylene-propylene (block and random) copolymers; propylene-α-olefin (α-olefin with 4 to 20 carbon atoms) copolymers; polyolefins such as polybutene and polypentene; grafted polyolefins obtained by graft-modifying these polyolefins with unsaturated carboxylic acids or their esters; ionomers; ethylene-vinyl acetate copolymers; ethylene-acrylic acid copolymers; ethylene-acrylic acid ester copolymers; polyester resins; polyamide resins (including copolymerized polyamides); polyvinyl chloride; polyvinylidene chloride; acrylic resins; polystyrene; vinyl ester resins; polyester elastomers; polyurethane elastomers; halogenated polyolefins such as chlorinated polyethylene and chlorinated polypropylene; aromatic or aliphatic polyketones; and polyalcohols obtained by reducing these. However, from the viewpoint of practicality, such as the physical properties (especially strength) of the laminate, polyolefin resins and polyamide resins are preferred, and polyethylenes and polypropylene are particularly preferred. These thermoplastic resins may be used individually or in combination of two or more types.

[0074] The resins used in these substrates may contain conventionally known antioxidants, antistatic agents, lubricants, nucleating agents, antiblocking agents, ultraviolet absorbers, waxes, etc., to the extent that they do not impede the spirit of the present invention.

[0075] The lamination method for laminating the resin composition of the present invention with other substrates can be carried out by known methods. For example, methods include melt-extrude lamination of other substrates onto a film, sheet, etc., of the resin composition of the present invention; conversely, melt-extrude lamination of the resin onto other substrates; co-extrusion of the resin and other substrates; dry lamination of the resin (layer) and other substrates (layers) using known adhesives such as organic titanium compounds, isocyanate compounds, polyester compounds, and polyurethane compounds; and coating a solution of the resin onto other substrates and then removing the solvent. Among these methods, co-extrusion is preferred from the standpoint of cost and environmental impact.

[0076] Furthermore, to impart dimensional stability after stretching, heat setting may be performed next. Heat setting can be carried out by well-known means; for example, the stretched film is heat-treated at a temperature of typically 80 to 180°C, preferably 100 to 165°C, for about 2 to 600 seconds while maintaining tension. Furthermore, when using a multilayer stretched film obtained from the resin composition of the present invention as a shrinkable film, in order to impart heat shrinkability, the above-mentioned heat fixing is omitted, and instead, a treatment such as applying cold air to the stretched film to cool and fix it is performed.

[0077] <Modifier for Modified EVOH> The modifier for modified EVOH of the present invention includes a hydrophilic organic compound (B) with an SP value greater than 13. In other words, the hydrophilic organic compound with an SP value greater than 13 used in the resin composition of the present invention is used as the modifier for the modified EVOH (A). This makes it possible to improve the wettability of the modified EVOH. Details regarding the modified EVOH(A) and hydrophilic organic compounds with an SP value greater than 13 have already been described, and therefore will be omitted here. [Examples]

[0078] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the invention. In the examples, "parts" and "%" refer to weight unless otherwise specified.

[0079] <Material> First, the details of the materials used in the examples and comparative examples are shown below. (A) Modified EVOH with aliphatic polyester units bonded to the side chain: Ethylene content 31 mol%, degree of saponification 99.7%, modification rate 6.1 mol%, average chain length of aliphatic polyester units 2, glass transition temperature 25°C, MFR 33 g / 10 min (210°C, 2.16 kg) • (B1) Pentaerythritol (Product name: Pentaerythritol, manufactured by Tokyo Chemical Industry Co., Ltd.) • (B2) meso-erythritol (product name meso-erythritol, manufactured by Tokyo Chemical Industry Co., Ltd.) • (B3) D-Sorbitol (Product name: D-Sorbitol, manufactured by Tokyo Chemical Industry Co., Ltd.) • (B4) 2,2-dimethyl-1,3-propanediol (product name 2,2-dimethyl-1,3-propanediol, manufactured by Tokyo Chemical Industry Co., Ltd.)

[0080] <Example 1> 11 g of modified EVOH with aliphatic polyester units attached to the side chains and 0.22 g of pentaerythritol were weighed out and melt-kneaded for 3 minutes at 180°C under a nitrogen atmosphere using a Leo Labs "Micro 15cc TwinScrewCompounder". The resulting resin composition was injection-molded at a mold temperature of 50°C and a cylinder temperature of 180°C to obtain a sheet test piece (30 mm × 80 mm × 2 mm) for contact angle measurement.

[0081] <Examples 2-8, Comparative Examples 1-5> The resin composition and test specimens were prepared in the same manner as in Example 1, except that the types and amounts of additives were changed as shown in Table 1.

[0082] [Measuring contact angle] Using the obtained test specimens, the contact angle was measured and evaluated under the following measurement conditions. The results are shown in Table 1. The measurement was performed using a Drop Master DM-300 contact angle meter (manufactured by Kyowa Interface Chemical Co., Ltd.) at 23°C and in a 50% RH atmosphere. The measurement samples used were the obtained test pieces stored for 3 days at 23°C and 50% RH. • Measurement method: Titration method. The procedure was performed using 2 μL of droplets, and the contact angle was checked 60 seconds after the water droplet came into contact with the surface of the sample.

[0083] [Table 1]

[0084] From the results above, it can be seen that in Examples 1 to 8, by adding a hydrophilic organic compound (B) with an SP value of 13 or more as a modified EVOH (A), the contact angle of the modified EVOH (A) is reduced and the wettability is improved compared to Comparative Example 1, in which no hydrophilic organic compound was added, and Comparative Examples 2 to 5, in which a hydrophilic organic compound with an SP value of 13 or less was added. [Industrial applicability]

[0085] The present invention relates to a resin composition comprising a modified EVOH (A) containing aliphatic polyester units and a hydrophilic organic compound (B) with an SP value greater than 13, as well as a molded product thereof and a modifier for modified EVOH. The molded product obtained from the above resin composition has excellent wettability, and consequently, its antifogging, antistatic, antifouling, and coating properties are improved, making it widely applicable.

Claims

1. A resin composition comprising a modified ethylene-vinyl alcohol resin (A) containing aliphatic polyester units and a hydrophilic organic compound (B), wherein the SP value of the hydrophilic organic compound (B) is greater than 13. A resin composition in which the content of the hydrophilic organic compound (B) is 0.1 to 30 parts by weight per 100 parts by weight of the modified ethylene-vinyl alcohol resin (A) containing the aliphatic polyester units.

2. The resin composition according to claim 1, wherein the hydrophilic organic compound (B) is a hydrophilic polyhydric alcohol.

3. The resin composition according to claim 1 or 2, wherein the SP value of the hydrophilic organic compound (B) is greater than 18.

4. A molded article comprising the resin composition according to any one of claims 1 to 3.

5. A modifier for modified ethylene-vinyl alcohol resins containing aliphatic polyester units, comprising 0.1 to 30 parts by weight of a hydrophilic organic compound with an SP value greater than 13 per 100 parts by weight of a modified ethylene-vinyl alcohol resin (A) containing aliphatic polyester units.

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