JP7776314B2 - Blow-molded article made of polyethylene naphthalate resin composition - Google Patents

Description

The present invention relates to a blow-molded article made from a polyethylene naphthalate resin composition that has excellent transparency and heat resistance and suppresses necking during the stretching process.

Polyethylene naphthalate resin has traditionally been used in a variety of applications due to its excellent mechanical properties, heat resistance, and chemical resistance. Furthermore, polyethylene naphthalate resin exhibits a slower crystallization rate in a static environment than polyethylene terephthalate resin, making it easy to obtain transparent molded products through injection molding. This has led to its use in transparent injection-molded products. Furthermore, stretching of polyethylene naphthalate resin results in highly oriented crystallization, improving mechanical strength and heat resistance while maintaining transparency. This has led to its use in resin pressure-resistant containers such as fire extinguisher containers. However, because the oriented crystallization of polyethylene naphthalate resin grows rapidly from the planar orientation of the naphthalene rings in the main chain, it is prone to localized constrictions known as necking. This necking directly leads to uneven wall thickness in blow-molded containers, making it difficult to produce containers with uniform wall thickness. This requires a high stretch ratio until necking is complete throughout the container, which places significant constraints on product design. Furthermore, increasing the stretch ratio leaves a large residual strain in the container, which creates the problem of the container deforming as the residual strain relaxes during the process of filling the container with hot contents or heat sterilization.

Regarding the suppression of necking in polyethylene naphthalate resin, Patent Document 1 exemplifies a resin composition comprising polyethylene naphthalate resin and a thermoplastic polyester resin exhibiting liquid crystallinity with a specific structure. Patent Document 2 exemplifies a resin composition comprising polyethylene naphthalate resin, a thermoplastic polyester resin exhibiting liquid crystallinity with a specific structure, and a compound having a reactive functional group. However, while improvements in container wall thickness due to necking were observed, the improvement was limited, as it occurred only in the range of high stretch ratios. Furthermore, the incompatibility between liquid crystal thermoplastic polyester resin and polyethylene naphthalate resin resulted in a significant decrease in transparency. Patent Document 3 discloses a resin composition comprising a copolymer polyester resin containing ethylene terephthalate units and ethylene naphthalate units and a polyetherimide resin. Patent Document 4 discloses a method for preventing fluorescence in polyalkylene naphthalate resin, characterized by adding a polyetherimide resin to the polyalkylene naphthalate resin. Furthermore, Patent Document 5 exemplifies a photographic film base composed of a blend of polyethylene naphthalate resin and polyetherimide resin, but neither has been verified to suppress necking.

Japanese Patent Application Laid-Open No. 2017-222794 Japanese Patent Application Laid-Open No. 2018-188547 Japanese Patent Application Publication No. 7-228761 Japanese Patent Application Publication No. 10-101916 Japanese Patent Application Publication No. 9-179242

The object of the present invention is to provide a blow-molded article made from a resin composition that has excellent transparency and heat resistance and suppresses necking during the stretching process.

As a result of extensive research aimed at achieving the above-mentioned objective, the inventors discovered that by adding a specific amount of polyetherimide resin to polyethylene naphthalate resin, it is possible to obtain a blow-molded article made from a resin composition that has excellent transparency and heat resistance and in which necking during the stretching process is suppressed, thereby resolving the above-mentioned problems.

That is, the object of the present invention is achieved by a blow-molded article obtained by blow-molding a resin composition characterized by containing 100 parts by weight of (A) polyethylene naphthalate resin (component A) and 60 to 150 parts by weight of (B) polyetherimide resin (component B).

The present invention provides a blow-molded article made from a resin composition that has excellent transparency and heat resistance and suppresses necking during the stretching process. The blow-molded article obtained by the present invention can be suitably used for pharmaceutical bottles, vials, and the like.

Further details of the present invention are explained below.

<About Component A>
The polyethylene naphthalate resin, which is component A of the present invention, can be produced using a dicarboxylic acid component mainly composed of naphthalenedicarboxylic acid and/or an ester-forming derivative of naphthalenedicarboxylic acid, and a glycol component mainly composed of ethylene glycol.

The naphthalenedicarboxylic acid component is primarily composed of 2,6-naphthalenedicarboxylic acid and 2,7-naphthalenedicarboxylic acid, but other dicarboxylic acids can be used in combination as long as the properties are not impaired. Examples of other dicarboxylic acids include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid, diphenylsulfone-4,4'-dicarboxylic acid, and diphenylether-4,4'-dicarboxylic acid; aliphatic dicarboxylic acids such as adipic acid, sebacic acid, succinic acid, and oxalic acid; and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. One or more of these may be used, and the amount can be selected as desired depending on the purpose. The amount of other dicarboxylic acids used is preferably 30 mol % or less, more preferably 20 mol % or less, based on the total acid components. The ester-forming derivatives of naphthalenedicarboxylic acid are primarily composed of dimethyl 2,6-naphthalenedicarboxylate and dimethyl 2,7-naphthalenedicarboxylate, but ester-forming derivatives of other dicarboxylic acids can be used in combination as long as the properties are not impaired. Examples of ester-forming derivatives of other dicarboxylic acids include lower dialkyl esters of aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid, diphenylsulfone-4,4'-dicarboxylic acid, and diphenylether-4,4'-dicarboxylic acid; lower dialkyl esters of alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; and lower dialkyl esters of aliphatic dicarboxylic acids such as adipic acid, sebacic acid, succinic acid, and oxalic acid. One or more of these may be used, and the amount can be selected as desired depending on the purpose. The amount of ester-forming derivatives of other dicarboxylic acids used is preferably 30 mol % or less, more preferably 20 mol % or less, based on the total dicarboxylic acid ester-forming derivative components.

A small amount of a tri- or higher functional carboxylic acid component such as trimellitic acid may also be used, or a small amount of an acid anhydride such as trimellitic anhydride may also be used. Also, a small amount of a hydroxycarboxylic acid such as lactic acid or glycolic acid, or an alkyl ester thereof, may also be used, and these can be selected as desired depending on the purpose.

The glycol component is primarily ethylene glycol, but other glycol components can be used in combination as long as the properties are not impaired. Examples of other glycol components include alkylene glycols such as 1,4-butanediol, 1,3-propylene glycol, 1,2-propylene glycol, neopentylene glycol, hexamethylene glycol, decamethylene glycol, cyclohexanedimethanol, diethylene glycol, triethylene glycol, poly(oxy)ethylene glycol, poly(oxy)tetramethylene glycol, and poly(oxy)methylene glycol. These can be selected arbitrarily depending on the purpose. A small amount of a polyhydric alcohol component such as glycerin may also be used. A small amount of an epoxy compound may also be used. The amount of other glycol components used is preferably 30 mol % or less, more preferably 20 mol % or less, based on the total glycol components.

The above-mentioned polyethylene naphthalate resin can be produced by conventionally known production methods. Specifically, it can be produced by a direct esterification method, in which a dicarboxylic acid component and a diol component are directly reacted, water is distilled off, and esterification is carried out, followed by polycondensation under reduced pressure; or by a transesterification method, in which a dicarboxylic acid dimethyl ester and a diol component are reacted, methyl alcohol is distilled off, and transesterification is carried out, followed by polycondensation under reduced pressure. Furthermore, solid-state polymerization can be carried out to increase the intrinsic viscosity.

Catalysts and stabilizers are preferably used during the above transesterification, esterification, and polycondensation reactions. Transesterification catalysts include Mg compounds, Mn compounds, Ca compounds, and Zn compounds, including acetates, monocarboxylates, alcoholates, and oxides. Esterification can be carried out using only dicarboxylic acids and diols without the addition of a catalyst, but it can also be carried out in the presence of a polycondensation catalyst, as described below. Polycondensation catalysts include Ge compounds, Ti compounds, and Sb compounds, including germanium dioxide, germanium hydroxide, germanium alcoholates, titanium tetrabutoxide, titanium tetraisopropoxide, and titanium oxalate. Phosphorus compounds are preferably used as stabilizers. Preferred phosphorus compounds include phosphoric acid and its esters, phosphorous acid and its esters, and hypophosphorous acid and its esters. Tertiary amines such as triethylamine, quaternary ammonium hydroxides such as tetraethylammonium hydroxide, and basic compounds such as sodium carbonate can also be added during the esterification reaction to suppress the by-production of diethylene glycol. The resulting polyester resin can also be blended with various stabilizers and modifiers.

The intrinsic viscosity of Component A is preferably 0.5 to 1.0 dl/g, more preferably 0.55 to 0.85 dl/g, and even more preferably 0.60 to 0.68 dl/g. If the intrinsic viscosity of Component A is less than 0.5 dl/g, the necking suppression effect may be poor, and if it exceeds 1.0 dl/g, the viscosity of the polyethylene naphthalate resin may be too high, which may result in poor bite during injection molding.

<About Component B>
The polyetherimide resin, which is component B of the present invention, is a resin containing a cyclic imide structure and is not particularly limited as long as it can be used for the purposes of the present invention, but a polyetherimide resin containing aliphatic or aromatic ether units and cyclic imide groups as repeating units is preferred. Furthermore, the main chain of the polyimide may contain structural units other than the cyclic imide and ether units, such as aromatic or aliphatic ester units and oxycarbonyl units, as long as the effects of the present invention are not impaired.

Specific examples of polyetherimide resins that can be preferably used in the present invention include polyetherimide resins represented by the following formula (1):

(In formula (1), n is an integer of 2 or greater, _R1 is a divalent aromatic or aliphatic group containing 6 to 30 carbon atoms, and _R2 is a divalent organic group selected from the group consisting of a divalent aromatic residue having 6 to 30 carbon atoms, an alkylene group having 2 to 20 carbon atoms, a cycloalkylene group having 2 to 20 carbon atoms, and a polydiorganosiloxane group chain-terminated with an alkylene group having 2 to 8 carbon atoms.)
Examples of R ₁ and R ₂ include aromatic residues and alkylene groups represented by the following formulae (2) to (8).

(In formula (8), n is an integer of 2 or more.)
In the present invention, polyetherimide resins represented by the following formula (9) are preferred from the viewpoint of compatibility with polyethylene naphthalate resins.

(In formula (9), n is an integer of 2 or more.)
Examples of this polyetherimide resin include "ULTEM1010" manufactured by SABIC Japan LLC.

The content of Component B is 60 to 150 parts by weight, preferably 65 to 120 parts by weight, and more preferably 70 to 100 parts by weight, per 100 parts by weight of Component A. If the content of Component B is less than 60 parts by weight, heat resistance and necking will not be improved, and the heat resistance of the blow-molded article will not be improved either. On the other hand, if the content exceeds 150 parts by weight, transparency will decrease.

(Other additives)
The resin composition of the present invention may contain various additives such as antioxidants and mold release agents, within the scope of the present invention.

<Antioxidants>
The resin composition of the present invention may contain at least one antioxidant selected from the group consisting of hindered phenol compounds, phosphite compounds, phosphonite compounds, and thioether compounds. The incorporation of an antioxidant not only stabilizes the color and fluidity during molding processing, but also has the effect of improving hydrolysis resistance.

Examples of hindered phenol compounds include α-tocopherol, butylhydroxytoluene, sinapyl alcohol, vitamin E, n-octadecyl-β-(4'-hydroxy-3',5'-di-tert-butylphenyl)propionate, 2-tert-butyl-6-(3'-tert-butyl-5'-methyl-2'-hydroxybenzyl)-4-methylphenyl acrylate, 2,6-di-tert-butyl-4-(N,N- dimethylaminomethyl)phenol, 3,5-di-tert-butyl-4-hydroxybenzylphosphonate diethyl ester, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 4,4'-methylenebis(2,6-di-tert-butylphenol), 2,2'-methylenebis(4-methyl-6-cyclohexylphenol), 2, 2'-dimethylene-bis(6-α-methyl-benzyl-p-cresol) 2,2'-ethylidene-bis(4,6-di-tert-butylphenol), 2,2'-butylidene-bis(4-methyl-6-tert-butylphenol), 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), triethylene glycol-N-bis-3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate , 1,6-hexanediol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], bis[2-tert-butyl-4-methyl 6-(3-tert-butyl-5-methyl-2-hydroxybenzyl)phenyl]terephthalate, 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1,-dimethylethyl}-2,4,8,10-tetramethyl Laoxaspiro[5,5]undecane, 4,4'-thiobis(6-tert-butyl-m-cresol), 4,4'-thiobis(3-methyl-6-tert-butylphenol), 2,2'-thiobis(4-methyl-6-tert-butylphenol), bis(3,5-di-tert-butyl-4-hydroxybenzyl)sulfide, 4,4'-di-thiobis(2,6-di-tert-butylphenol), 4,4'-tri-thiobis(2 ,6-di-tert-butylphenol), 2,2-thiodiethylenebis-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,4-bis(n-octylthio)-6-(4-hydroxy-3',5'-di-tert-butylanilino)-1,3,5-triazine, N,N'-hexamethylenebis-(3,5-di-tert-butyl-4-hydroxyhydrocinnamide), N,N'-bis[3-(3, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, tris(3,5-di-tert-butyl-4-hydroxyphenyl)isocyanurate, tris(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine, Examples of the hydroxybenzyl isocyanurate include 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate, 1,3,5-tris-2[3(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]ethyl isocyanurate, and tetrakis[methylene-3-(3',5'-di-tert-butyl-4-hydroxyphenyl)propionate]methane. Among the above compounds, tetrakis[methylene-3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate]methane, octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and 3,9-bis[2-{3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane are preferred. Octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate is particularly preferred. All of these are readily available. The above hindered phenol compounds can be used alone or in combination of two or more.

Phosphite compounds include triphenyl phosphite, tris(nonylphenyl) phosphite, tridecyl phosphite, trioctyl phosphite, trioctadecyl phosphite, didecyl monophenyl phosphite, dioctyl monophenyl phosphite, diisopropyl monophenyl phosphite, monobutyl diphenyl phosphite, monodecyl diphenyl phosphite, monooctyl diphenyl phosphite, tris(diethylphenyl) phosphite, tris(di-isopropylphenyl) phosphite, tris(di-n-butylphenyl) phosphite, tris(2,4-di-tert-butylphenyl) phosphite, tris(2,6-di-tert-butyl phenyl)phosphite, distearyl pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-ethylphenyl)pentaerythritol diphosphite, bis{2,4-bis(1-methyl-1-phenylethyl)phenyl}pentaerythritol diphosphite, phenylbisphenol A pentaerythritol diphosphite, bis(nonylphenyl)pentaerythritol diphosphite, and dicyclohexyl pentaerythritol diphosphite are also examples of phosphite compounds that can be used. Examples include 2,2'-methylenebis(4,6-di-tert-butylphenyl)(2,4-di-tert-butylphenyl)phosphite, 2,2'-methylenebis(4,6-di-tert-butylphenyl)(2-tert-butyl-4-methylphenyl)phosphite, and 2,2-methylenebis(4,6-di-tert-butylphenyl)octylphosphite. Suitable phosphite compounds are distearyl pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, and bis{2,4-bis(1-methyl-1-phenylethyl)phenyl}pentaerythritol diphosphite.

Also available is, for example, 2,4,8,10-tetra-t-butyl-6-[3-(3-methyl-4-hydroxy-5-t-butylphenyl)propoxy]dibenzo[d,f][1,3,2]dioxaphosphepine (commercially available as "Sumilizer GP" (Sumitomo Chemical Co., Ltd.)). ], 2,10-dimethyl-4,8-di-t-butyl-6-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propoxy]-12H-dibenzo[d,g][1,3,2]dioxaphosphocin, 2,4,8,10-tetra-t-butyl-6-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propoxy]dibenzo[d,f][1,3,2]dioxaphosphepine, 2,4,8,10-tetra-t-pentyl-6-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propoxy]-12-methyl-12H-dibenzo[d,g][1,3,2]dioxaphosphocin, Dimethyl-4,8-di-t-butyl-6-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]-12H-dibenzo[d,g][1,3,2]dioxaphosphocin, 2,4,8,10-tetra-t-pentyl-6-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]-12-methyl-12H-dibenzo[d,g][1,3,2]dioxaphosphocin, 2,4,8,10-tetra-t-butyl-6-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]-dibenzo[d,f][1,3,2]dioxaphosphepine , 2,10-dimethyl-4,8-di-t-butyl-6-(3,5-di-t-butyl-4-hydroxybenzoyloxy)-12H-dibenzo[d,g][1,3,2]dioxaphosphocin, 2,4,8,10-tetra-t-butyl-6-(3,5-di-t-butyl-4-hydroxybenzoyloxy)-12-methyl-12H-dibenzo[d,g][1,3,2]dioxaphosphocin, 2,10-dimethyl-4,8-di-t-butyl-6-[3-(3-methyl-4-hydroxy-5-t-butylphenyl)propoxy]-12H-dibenzo[d,g][1,3,2]dioxaphosphocin, Examples of suitable phosphite compounds include 2,10-diethyl-4,8-di-t-butyl-6-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propoxy]-12H-dibenzo[d,g][1,3,2]dioxaphosphocin, 2,10-diethyl-4,8-di-t-butyl-6-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propoxy]-12H-dibenzo[d,g][1,3,2]dioxaphosphocin, and 2,4,8,10-tetra-t-butyl-6-[2,2-dimethyl-3-(3-t-butyl-4-hydroxy-5-methylphenyl)propoxy]-dibenzo[d,f][1,3,2]dioxaphosphepine. All of these compounds are readily available. The above phosphite compounds can be used alone or in combination of two or more.

Phosphonite compounds include tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite, tetrakis(2,4-di-tert-butylphenyl)-4,3'-biphenylene diphosphonite, tetrakis(2,4-di-tert-butylphenyl)-3,3'-biphenylene diphosphonite, tetrakis(2,6-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite, tetrakis(2,6-di-tert-butylphenyl)-4,3'-biphenylene diphosphonite, tetrakis(2 Examples of the bis(2,6-di-tert-butylphenyl)-3,3'-biphenylene diphosphonite include bis(2,4-di-tert-butylphenyl)-4-phenyl-phenylphosphonite, bis(2,4-di-tert-butylphenyl)-3-phenyl-phenylphosphonite, bis(2,6-di-n-butylphenyl)-3-phenyl-phenylphosphonite, bis(2,6-di-tert-butylphenyl)-4-phenyl-phenylphosphonite, and bis(2,6-di-tert-butylphenyl)-3-phenyl-phenylphosphonite. Preferred are tetrakis(di-tert-butylphenyl)-biphenylene diphosphonite and bis(di-tert-butylphenyl)-phenyl-phenylphosphonite, and more preferred are tetrakis(2,4-di-tert-butylphenyl)-biphenylene diphosphonite and bis(2,4-di-tert-butylphenyl)-phenyl-phenylphosphonite. Such phosphonite compounds can be used in combination with, and are preferred to be used in combination with, the above-mentioned phosphite compounds having an aryl group substituted with two or more alkyl groups. Tetrakis(2,4-di-tert-butylphenyl)-biphenylene diphosphonite is preferred as the phosphonite compound, and stabilizers containing this phosphonite as the main component are commercially available as Sandostab P-EPQ (trademark, manufactured by Clariant) and Irgafos P-EPQ (trademark, manufactured by CIBA SPECIALTY CHEMICALS), either of which can be used. The above-mentioned phosphonite compounds can be used alone or in combination of two or more.

Specific examples of thioether compounds include dilauryl thiodipropionate, ditridecyl thiodipropionate, dimyristyl thiodipropionate, distearyl thiodipropionate, pentaerythritol tetrakis(3-lauryl thiopropionate), pentaerythritol tetrakis(3-dodecyl thiopropionate), pentaerythritol tetrakis(3-octadecyl thiopropionate), pentaerythritol tetrakis(3-myristyl thiopropionate), and pentaerythritol tetrakis(3-stearyl thiopropionate). The above thioether compounds can be used alone or in combination of two or more.

The content of the antioxidant is preferably 0.01 to 2 parts by weight, more preferably 0.03 to 1 part by weight, and even more preferably 0.05 to 0.5 parts by weight, per 100 parts by weight of Component A. If the content of the antioxidant is less than 0.01 part by weight, the antioxidant effect will be insufficient, resulting in unstable color and fluidity during molding and processing, as well as reduced hydrolysis resistance. Furthermore, if the content is more than 2 parts by weight, reactive components derived from the antioxidant may actually reduce hydrolysis resistance.

It is also preferable to use the above-mentioned hindered phenol compound in combination with two or more of a phosphite compound, a phosphonite compound, or a thioether compound. Using a hindered phenol compound in combination with two or more of a phosphite compound, a phosphonite compound, or a thioether compound produces a synergistic effect as a stabilizer, which is more effective in stabilizing color and fluidity during molding and improving hydrolysis resistance.

<Release Agent>
The resin composition of the present invention can contain a release agent. Specific examples of the release agent include fatty acids, fatty acid metal salts, oxyfatty acids, paraffins, low-molecular-weight polyolefins, fatty acid amides, alkylenebisfatty acid amides, aliphatic ketones, partially saponified fatty acid esters, fatty acid lower alcohol esters, fatty acid polyhydric alcohol esters, fatty acid polyglycol esters, and modified silicones. By blending these, molded articles with excellent mechanical properties, moldability, and heat resistance can be obtained.

Fatty acids having 6 to 40 carbon atoms are preferred, and specific examples include oleic acid, stearic acid, lauric acid, hydroxystearic acid, behenic acid, arachidonic acid, linoleic acid, linolenic acid, ricinoleic acid, palmitic acid, montanic acid, and mixtures thereof. Fatty acid metal salts are preferably alkali (earth) metal salts of fatty acids having 6 to 40 carbon atoms, and specific examples include calcium stearate, sodium montanate, and calcium montanate.

Examples of hydroxy fatty acids include 1,2-hydroxysteric acid. Paraffins with 18 or more carbon atoms are preferred, including liquid paraffin, natural paraffin, microcrystalline wax, and petrolactam.

Preferably, low-molecular-weight polyolefins have a molecular weight of 5,000 or less, and specific examples include polyethylene wax, maleic acid-modified polyethylene wax, oxidized polyethylene wax, chlorinated polyethylene wax, and polypropylene wax.

Fatty acid amides with 6 or more carbon atoms are preferred, and specific examples include oleic acid amide, erucic acid amide, and behenic acid amide.

Alkylene bis(fatty acid amides) having 6 or more carbon atoms are preferred, and specific examples include methylene bis(stearic acid amide), ethylene bis(stearic acid amide), and N,N-bis(2-hydroxyethyl)stearic acid amide.

Aliphatic ketones with 6 or more carbon atoms are preferred, including higher aliphatic ketones.

Partially saponified fatty acid esters include partially saponified montanic acid esters. Fatty acid lower alcohol esters include stearic acid esters, oleic acid esters, linoleic acid esters, linolenic acid esters, adipic acid esters, behenic acid esters, arachidonic acid esters, montanic acid esters, and isostearic acid esters.

Examples of fatty acid polyhydric alcohol esters include glycerol tristearate, glycerol distearate, glycerol monostearate, pentaerythritol tetrastearate, pentaerythritol tristearate, pentaerythritol dimyristate, pentaerythritol monostearate, pentaerythritol adipate stearate, and sorbitan monobehenate. Examples of fatty acid polyglycol esters include polyethylene glycol fatty acid esters, polytrimethylene glycol fatty acid esters, and polypropylene glycol fatty acid esters.

Modified silicones include polyether-modified silicones, higher fatty acid alkoxy-modified silicones, higher fatty acid-containing silicones, higher fatty acid ester-modified silicones, methacrylic-modified silicones, and fluorine-modified silicones.

Among these, fatty acids, fatty acid metal salts, oxyfatty acids, fatty acid esters, partially saponified fatty acid esters, paraffin, low-molecular-weight polyolefins, fatty acid amides, and alkylene bisfatty acid amides are preferred, with partially saponified fatty acid esters and alkylene bisfatty acid amides being more preferred. Among these, montanic acid esters, partially saponified montanic acid esters, polyethylene wax, acid-value polyethylene wax, sorbitan fatty acid esters, erucic acid amide, and ethylene bisstearic acid amide are preferred, with partially saponified montanic acid esters and ethylene bisstearic acid amide being particularly preferred.

One type of release agent may be used, or two or more types may be used in combination. The content of the release agent is preferably 0.01 to 3 parts by weight, and more preferably 0.03 to 2 parts by weight, per 100 parts by weight of Component A.

<Method of producing resin composition>
Any method can be used to produce the resin composition of the present invention. For example, the components and optionally other components can be premixed, followed by melt-kneading and pelletizing. Examples of premixing methods include a Nauta mixer, a V-blender, a Henschel mixer, a mechanochemical device, and an extrusion mixer. Premixing can also be performed using an extrusion granulator or briquetting machine. After premixing, the components are melt-kneaded in a melt mixer, typically a vented twin-screw extruder, and pelletized using a pelletizer or other device. Other examples of melt mixers include a Banbury mixer, a kneading roll, and a thermostatically controlled stirring vessel. A vented twin-screw extruder is preferred. Alternatively, the components and optionally other components can be fed independently to a melt mixer, typically a twin-screw extruder, without premixing.

<Preform molding>
The resin composition of the present invention is typically obtained as pellets, which are then used as a raw material to mold a preform. While various molding methods, such as injection molding, press molding, and extrusion molding, can be selected, injection molding and press molding are preferred from the viewpoint of rapidly cooling the preform without crystallizing it. Injection molding can be performed using not only conventional cold runner molding methods but also hot runner molding methods. In such injection molding, molded articles can be obtained using injection molding methods such as injection compression molding, injection press molding, foam molding (including injection of supercritical fluids), insert molding, in-mold coating molding, and rapid heating and cooling mold molding, depending on the purpose. For example, in the case of injection molding of a preform for blow molding, it is preferable to pre-dry each pellet in a hot air dryer at 130 to 150°C for 7 hours or more, then melt it at a cylinder temperature of 280 to 310°C and injection mold it. If the pre-drying temperature is less than 130°C, drying will be insufficient, and residual moisture in the pellets may cause resin decomposition and unstable intrinsic viscosity, while if the pre-drying temperature is higher than 150°C, the pellets may fuse together and form clumps, making metering during injection molding unstable. The mold temperature during molding is preferably 40 to 140°C, and more preferably 60 to 120°C. If the mold temperature is lower than 40°C, appearances such as flow marks may appear on the surface of the molded article, and if the mold temperature exceeds 140°C, the molded article may deform during release, potentially preventing the formation of uniform containers during blow molding.

<Blow molding>
Any method can be used to produce the blow-molded article of the present invention. Examples include direct blow molding, extrusion direct blow molding, one-stage biaxial stretch blow molding, and two-stage biaxial stretch blow molding. When using two-stage biaxial stretch blow molding, it is preferable to preheat the preform (preheating) before blow molding. The preheating temperature is preferably 70 to 140°C, more preferably 90 to 130°C, and particularly preferably 100 to 110°C. If the preheating temperature is below 70°C, the subsequent main heating process will take a long time. If the preheating temperature exceeds 140°C, the resin composition will soften, causing the preform to deform and potentially preventing the production of a uniform blow-molded container. Preheating can be performed by any method, such as storing the preform in a hot air dryer or using an infrared heater. Heating during blow molding (main heating) can be performed both from the inside of the preform (internal heating) and from the outside of the preform (external heating). Infrared heating is preferred due to its high heating efficiency. Here, the resin temperature needs to be raised to about 150 to 200° C. Blow molding within this resin temperature range makes it possible to obtain a good blow molded article with little unevenness in thickness and no breaks.

<Blow molded article>
The blow-molded article of the present invention has a container shape consisting of a mouth portion serving as an opening, a body portion, and a bottom portion, and the stretch ratio (A) at the midpoint of the body portion calculated by the following formula (1) is preferably 1.1 to 4, more preferably 1.1 to 3. If the stretch ratio exceeds 4, the container may be deformed when filled with hot contents or by heat treatment such as heat sterilization. On the other hand, if the stretch ratio is less than 1.1, adhesion to the mold may be insufficient, resulting in poor shaping.

A=T0/T1 (1)
(In formula (1), T0 represents the thickness (mm) at the center of the body of the preform, and T1 represents the thickness (mm) at the center of the body of the container after blow molding.)

The following examples illustrate embodiments of the present invention, but the present invention is not limited to these examples. Physical properties were evaluated using the following methods.

[Evaluation of Resin Composition]
(1) Transparency Pellets obtained by the method described below were dried at 140°C for 7 hours, and then molded into test pieces 25 mm long, 50 mm wide, and 1 mm thick using an injection molding machine (EC130SXII-4Y manufactured by Toshiba Machine Co., Ltd.) at a cylinder temperature of 310°C and a mold temperature of 90°C. The light transmittance at a wavelength of 450 nm was measured using a UV-visible spectrophotometer V-560 manufactured by JASCO Corporation. The light transmittance must be 60% or more.

(2) Heat Resistance Pellets obtained by the method described below were dried at 140°C for 7 hours, and then test specimens were prepared using an injection molding machine (EC130SXII-4Y, manufactured by Toshiba Machine Co., Ltd.) at a cylinder temperature of 310°C and a mold temperature of 90°C, and the deflection temperature under load was measured in accordance with ISO 75-1 and 75-2. The deflection temperature under load must be 120°C or higher under a load of 1.8 MPa.

(3) Glass Transition Temperature Using pellets obtained by the following method, the glass transition temperature (Tg) was measured at a temperature rise rate of 20°C/min with a differential scanning calorimeter (manufactured by TA Instruments Japan, Inc.: DSC-2910).

(4) Necking Degree After drying the pellets obtained by the method described below at 140°C for 7 hours, dumbbell pieces conforming to ISO 527-1 and 527-2 were produced using an injection molding machine (Toshiba Machine Co., Ltd., EC130SXII-4Y) at a cylinder temperature of 310°C and a mold temperature of 90°C. The tensile test conditions were set to simulate blow molding, with a tensile speed of 1000 mm/min and a tensile temperature 25°C higher than the glass transition temperature of the resin composition, and the tensile test was performed until the nominal tensile strain reached 100%. The necking degree was calculated using the cross-sectional area of the necking site and the theoretical cross-sectional area using the following formula. The theoretical cross-sectional area here refers to the cross-sectional area when the volume is assumed to be constant without taking volume shrinkage into account. A smaller necking degree means that the necking phenomenon is suppressed, and it must be 20% or less.
Necking degree (%)=[(theoretical cross-sectional area−cross-sectional area of necked portion)/theoretical cross-sectional area]×100

(5) Heat resistance of blow-molded containers The pellets obtained by the method described below were dried in a hot air dryer at 140 ° C. for 7 hours, and then molded at a cylinder temperature of 310 ° C. and a mold temperature of 90 ° C. using an EC 160NII-4Y manufactured by Toshiba Machine Co., Ltd. to obtain a preform with a thickness of 2.5 mm. Next, a Frontier FDB-1D was used as a blowing machine, and a 300 ml container-shaped blow mold (1.0 times vertical, 2.2 times horizontal) was used to perform biaxial stretch blow molding of the preform in the following manner. First, the preform that had been preheated in a hot air dryer at 100 ° C. for 1 hour was placed in the blow molding machine, and the output of the IR heater was set so that the preform surface temperature was 25 ° C. higher than the glass transition temperature, and this heating was performed. Next, the rod stretching speed was 60%, the primary blow delay time was 1 second, the primary blow time was 0.3 seconds, the primary blow pressure was 3.4 MPa, the secondary blow time was 5 seconds, and the secondary blow pressure was 3. Blow molding was carried out under conditions of 4 MPa and a mold temperature of 70° C. The thickness of the central part of the body of the blow-molded container was measured, and the stretch ratio (A) was calculated using the following formula (1).

A=T0/T1 (1)
(In formula (1), T0 represents the thickness (mm) at the center of the body of the preform, and T1 represents the thickness (mm) at the center of the body of the container after blow molding.)

The resulting blow-molded container was immersed in boiling water for 10 hours, and the rate of change in content volume before and after immersion was calculated using the following formula: The rate of change in content volume is preferably 3% or less.
Percent change in content (%) = [(volume before boiling water treatment - volume after boiling water treatment) / volume before boiling water treatment] x 100

[Examples 1-6, Comparative Examples 1-3]
According to the contents shown in Table 1, components A and B were separately fed into a twin-screw extruder through the first feed port, and were melt-kneaded and extruded at a temperature of 310°C to form pellets. Here, the first feed port refers to the feed port at the base. The twin-screw extruder used was a vented twin-screw extruder with a diameter of 30 mm (TEX30α-31.5BW-2V, manufactured by The Japan Steel Works, Ltd.).

The following materials were used in the examples and comparative examples of the present invention.
(Component A)
AI: Polyethylene naphthalate resin obtained in Production Example I <Production Example I>
100 parts by weight of dimethyl naphthalenedicarboxylate and 51 parts by weight of ethylene glycol were subjected to a conventional transesterification reaction using 0.003 parts by weight (0.012 mmol) of cobalt acetate tetrahydrate, 0.014 parts by weight (0.08 mmol) of calcium acetate monohydrate, and 0.044 parts by weight (0.0205 mmol) of manganese acetate tetrahydrate as transesterification catalysts. 1.5 parts by weight (0.14 mmol) of a 1% solution of amorphous germanium dioxide in ethylene glycol was added, followed by the addition of 0.0057 parts by weight (0.41 mmol) of trimethyl phosphate to terminate the transesterification reaction. Solid-state polymerization was then carried out for 8 hours at 227°C under a vacuum of 0.5 Torr to obtain a polyethylene naphthalate resin having an intrinsic viscosity of 0.60 dL/g.

(B component)
B-I: ULTEM1010 (product name) manufactured by SABIC Japan LLC

<Examples 1 to 6>
Because the composition is within the scope of the present invention, it is possible to obtain a blow molded article that is excellent in transparency and heat resistance, has improved necking, and is excellent in heat resistance.

<Comparative Examples 1 and 2>
Because the content of component B was low, the heat resistance and necking were not improved, and no improvement in the heat resistance of the blow-molded article was observed.

<Comparative Example 3>
Since the content of component B exceeded the upper limit, the transparency was poor.

Claims (4)

A blow-molded article obtained by blow-molding a resin composition characterized by containing 100 parts by weight of (A) polyethylene naphthalate resin (component A) and 100 to 150 parts by weight of (B) polyetherimide resin (component B). The blow-molded article according to claim 1, characterized in that the container has a shape consisting of a mouth portion that serves as an opening, a body portion, and a bottom portion, and a stretch ratio (A) at a midpoint of the body portion calculated by the following formula (1) is 1.1 to 4:
A=T0/T1 (1)
(In formula (1), T0 represents the thickness (mm) at the center of the body of the preform, and T1 represents the thickness (mm) at the center of the body of the container after blow molding.) The blow-molded article according to claim 1 or 2 is a pharmaceutical storage container. The blow-molded article according to claim 1 or 2, which is a vial.