JP2018104625A - Resin composition, melt-molded product using the same, and multilayer structure - Google Patents

Abstract

The present invention provides a resin composition capable of obtaining a melt-molded product having excellent transparency and gas barrier properties and having an ability to absorb wavelengths in a specific ultraviolet region. An ethylene-vinyl ester copolymer saponified resin composition having an ultraviolet transmittance of 40% or less at a wavelength of 250 nm and 95% or more at a wavelength of 500 nm when the thickness is 30 μm is used. [Selection figure] None

Description

  The present invention relates to a resin composition comprising a saponified ethylene-vinyl ester copolymer (hereinafter sometimes abbreviated as “EVOH”), a melt-molded product using the same, and a layer structure. More specifically, the present invention relates to a resin composition excellent in ultraviolet absorbing ability and gas barrier property, a melt-molded product using the same, and a multilayer structure including a resin composition layer.

  Gas barrier properties, particularly oxygen barrier properties are often required for packaging materials for packaging foods and various articles. This is in order to prevent the effects of oxidative deterioration of the package contents due to oxygen or the like, and to maintain the freshness of the food for a long time. For this reason, in the conventional packaging material, the gas barrier layer which prevents permeation | transmission of oxygen was provided, and permeation | transmission of oxygen etc. was prevented.

  As a gas barrier layer, attention has been paid to EVOH having high transparency. Since EVOH has low barrier properties due to the presence of moisture, for example, a film layer obtained by melt-molding EVOH as a melt-molding material is used as an intermediate layer, and a resin layer made of a thermoplastic resin is formed on both sides of this EVOH film layer. The formed multilayer structure is used for various packaging materials. As described above, such a multilayer structure is a film as a food packaging material, a pharmaceutical packaging material such as a pharmaceutical packaging material, an industrial chemical packaging material, and an agrochemical packaging material, utilizing its excellent gas barrier property and transparency. And molded into a container such as a sheet or a bottle.

  However, since the multilayer structure has excellent transparency, it transmits not only visible light but also ultraviolet rays, so that the problem of deterioration of the packaged contents due to ultraviolet rays may occur. is there. For this reason, by adding a water-soluble ultraviolet absorber to a resin film such as polyvinyl alcohol, which is a kind of film having gas barrier properties, the content is excellent in transparency and transmitted through ultraviolet rays. A technique for preventing photodegradation of light is proposed (see, for example, Patent Document 1).

JP 51-132259 A

However, in the technique described in Patent Document 1, when used as a packaging material for a long time, the ultraviolet absorbent bleeds out due to the contents, resulting in a decrease in appearance, a decrease in ultraviolet absorption effect, and odor. There was a risk of problems such as this.
In addition, when the multilayer structure is used as a packaging material for foods, drugs, etc., the contents of the foods and drugs are UV-B having a wavelength region of less than 320 nm, UV-C having a wavelength region of less than 280 nm, and the like. As a result, it is known that the contents of food and medicines are greatly altered. In particular, in recent years, the highest energy UV-C, which has not been transmitted through the atmosphere in the past, reaches the earth's surface due to the expansion of the ozone hole due to the destruction of the ozone layer. There has been a demand for a material having an ultraviolet absorption effect.

  Therefore, the present invention, under such a background, has a resin composition having excellent transparency and gas barrier properties and having an absorption ability of a wavelength in a specific ultraviolet region (for example, UV-C having a wavelength of less than 280 nm) and An object of the present invention is to provide a melt-molded product using the same and a multilayer structure.

  However, as a result of intensive studies in view of the above circumstances, the present inventor solves the above object by using a saponified ethylene-vinyl ester copolymer as a gas barrier resin and blending a small amount of chlorine resin therein. As a result, the present invention has been completed.

  That is, the gist of the present invention is an ethylene-vinyl ester copolymer saponified resin composition having an ultraviolet transmittance of 40% or less at a wavelength of 250 nm and 95% or more at a wavelength of 500 nm when the thickness is 30 μm. Exist.

  The second gist of the present invention is a melt-molded product obtained by melt-molding the resin composition, and the third gist is a multilayer structure having at least one layer made of the resin composition.

  ADVANTAGE OF THE INVENTION According to this invention, the resin composition which has the absorption capability of the wavelength (for example, UV-C of wavelength less than 280 nm) of a specific ultraviolet region is obtained, having the outstanding transparency and gas barrier property.

  Hereinafter, although the structure of this invention is demonstrated in detail, these show an example of a desirable embodiment.

The present invention relates to an ethylene-vinyl ester copolymer saponified resin composition having an ultraviolet transmittance of 40% or less at a wavelength of 250 nm and 95% or more at a wavelength of 500 nm when the thickness is 30 μm. .
Such a resin composition includes, for example, an ethylene-vinyl ester copolymer saponified resin composition containing a chlorine resin, and the content thereof is a total amount of an ethylene-vinyl ester copolymer saponified product and a chlorine resin. It is obtained by making it small with respect to.
Hereinafter, such a resin composition will be described.

<EVOH>
EVOH used in the present invention will be described.
EVOH used in the present invention is usually a resin obtained by copolymerization of ethylene and a vinyl ester monomer and then saponification, and is a water-insoluble thermoplastic resin. As the polymerization method, any known polymerization method such as solution polymerization, suspension polymerization, and emulsion polymerization can be used. In general, solution polymerization using methanol as a solvent is used. Saponification of the obtained ethylene-vinyl ester copolymer can also be performed by a known method.
That is, EVOH used in the present invention mainly comprises an ethylene structural unit and a vinyl alcohol structural unit, and contains a slight amount of vinyl ester structural unit remaining without being saponified.

  As the vinyl ester-based monomer, vinyl acetate is typically used because it is easily available from the market and has good treatment efficiency of impurities during production. In addition, for example, vinyl formate, vinyl propionate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl versatate, etc. Examples thereof include aromatic vinyl esters such as vinyl acid, and are usually aliphatic vinyl esters having 3 to 20 carbon atoms, preferably 4 to 10 carbon atoms, and particularly preferably 4 to 7 carbon atoms. These are usually used alone, but a plurality of them may be used simultaneously as necessary.

  The content of the ethylene structural unit in EVOH is a value measured based on ISO 14663, and is usually 20 to 60 mol%, preferably 25 to 50 mol%, particularly preferably 25 to 35 mol%. If the content is too small, the gas barrier property and melt moldability at high humidity tend to decrease, and conversely if too large, the gas barrier property tends to decrease.

  The saponification degree of the vinyl ester component in EVOH is a value measured based on JIS K6726 (where EVOH is a solution uniformly dissolved in water / methanol solvent), and is usually 90 to 100 mol%, preferably 95 -100 mol%, particularly preferably 99-100 mol%. When the degree of saponification is too low, gas barrier properties, thermal stability, moisture resistance and the like tend to decrease.

  Further, the melt flow rate (MFR) (210 ° C., load 2160 g) of the EVOH is usually 0.5 to 100 g / 10 minutes, preferably 1 to 50 g / 10 minutes, particularly preferably 3 to 35 g / 10 minutes. It is. If the MFR is too high, the film forming property tends to be lowered. Moreover, when MFR is too low, there exists a tendency for melt extrusion to become difficult.

In addition, the EVOH used in the present invention may further contain structural units derived from the comonomer shown below within a range not inhibiting the effects of the present invention (for example, 10 mol% or less).
Examples of the comonomer include olefins such as propylene, 1-butene, isobutene, 2-propen-1-ol, 3-buten-1-ol, 4-penten-1-ol, and 5-hexen-1-ol. 3,4-dihydroxy-1-butene, hydroxy-containing α-olefins such as 5-hexene-1,2-diol, and 3,4-diacyloxy-1-butenes, which are esterified products thereof, especially 3 2,3-diacetoxy-1-butene, 2,3-diacetoxy-1-allyloxypropane, 2-acetoxy-1-allyloxy-3-hydroxypropane, 3-acetoxy-1-allyloxy-2-hydroxypropane, glycerol mono Derivatives such as acylated products such as vinyl ether and glycerin monoisopropenyl ether; 2-methylenepropane-1 Hydroxyalkylvinylidenes such as 3-diol and 3-methylenepentane-1,5-diol; 1,3-diacetoxy-2-methylenepropane, 1,3-dipropionyloxy-2-methylenepropane, 1,3-dibuti Hydroxyalkyl vinylidene diacetates such as ronyloxy-2-methylenepropane; unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, (anhydrous) phthalic acid, (anhydrous) maleic acid, (anhydrous) itaconic acid or the like Salts or mono- or dialkyl esters having 1 to 18 carbon atoms; acrylamide, N-alkyl acrylamide having 1 to 18 carbon atoms, N, N-dimethylacrylamide, 2-acrylamidopropanesulfonic acid or a salt thereof, acrylamidopropyldimethylamine or a salt thereof Acid salt or its Acrylamides such as quaternary salts; methacrylamide, N-alkylmethacrylamide having 1 to 18 carbon atoms, N, N-dimethylmethacrylamide, 2-methacrylamidepropanesulfonic acid or its salt, methacrylamidepropyldimethylamine or its acid Methacrylamides such as salts or quaternary salts thereof; N-vinylamides such as N-vinylpyrrolidone, N-vinylformamide, and N-vinylacetamide; vinyl cyanides such as acrylonitrile and methacrylonitrile; Vinyl ethers such as alkyl vinyl ethers, hydroxyalkyl vinyl ethers and alkoxyalkyl vinyl ethers; vinyl halide compounds such as vinyl fluoride, vinylidene fluoride and vinyl bromide (excluding chlorinated vinyl compounds); Vinyl silanes such as toxivinyl silane; allyl compounds such as allyl acetate; allyl alcohols such as allyl alcohol and dimethoxyallyl alcohol; trimethyl- (3-acrylamido-3-dimethylpropyl) -ammonium chloride, acrylamido-2-methylpropanesulfone And comonomers such as acids.

  Furthermore, “post-modified” EVOH such as urethanization, acetalization, cyanoethylation, oxyalkylenation and the like can also be used.

  In particular, EVOH having a primary hydroxy group in the side chain is preferable in terms of good secondary moldability, and EVOH having 1,2-diol in the side chain is particularly preferable.

  Further, the EVOH used in the present invention may be a mixture with other different EVOH, and as the other EVOH, those having different contents of ethylene structural units, those having different saponification degrees, melt flow Examples include those having different rates (MFR) and those having different copolymerization components.

  In the EVOH (A) used in the present invention, a compounding agent generally blended with EVOH, for example, a heat stabilizer, an antioxidant, an antistatic agent, a colorant, and an ultraviolet absorber, as long as the effects of the present invention are not impaired. , Lubricant, plasticizer, light stabilizer, surfactant, antibacterial agent, drying agent, antiblocking agent, flame retardant, crosslinking agent, curing agent, foaming agent, crystal nucleating agent, antifogging agent, biodegradation additive, A silane coupling agent, an oxygen absorbent and the like may be contained.

The heat stabilizer is an organic acid such as acetic acid, propionic acid, butyric acid, lauric acid, stearic acid, oleic acid, behenic acid, or an alkali thereof for the purpose of improving various physical properties such as heat stability during melt molding. Metal salts (sodium, potassium, etc.), alkaline earth metal salts (calcium, magnesium, etc.), salts such as zinc salts; or inorganic acids such as sulfuric acid, sulfurous acid, carbonic acid, phosphoric acid, boric acid, or alkali metals thereof You may mix | blend additives, such as salt (sodium, potassium, etc.), alkaline-earth metal salt (calcium, magnesium, etc.), and zinc salt.
Among these, it is particularly preferable to blend boron compounds including acetic acid, boric acid and salts thereof, acetates and phosphates.

  When acetic acid is blended, the blending amount is usually 0.001 to 1 part by weight, preferably 0.005 to 0.2 part by weight, particularly preferably 0.01 to 0 part per 100 parts by weight of EVOH (A). .1 part by weight. If the blending amount of acetic acid is too small, there is a tendency that the effect of containing acetic acid is not sufficiently obtained, and conversely if it is too much, it tends to be difficult to obtain a uniform film.

  Moreover, when a boron compound is blended, the blending amount is usually 0.001 to 1 part by weight in terms of boron (analyzed by ICP emission analysis after ashing) with respect to 100 parts by weight of EVOH (A). , Preferably 0.002 to 0.2 parts by weight, particularly preferably 0.005 to 0.1 parts by weight. If the compounding amount of the boron compound is too small, the effect of containing the boron compound may not be obtained sufficiently, and conversely if it is too much, it tends to be difficult to obtain a uniform film.

  In addition, the amount of acetate and phosphate (including hydrogen phosphate) is usually 0 in terms of metal (after ashing and analyzed by ICP emission spectrometry) with respect to 100 parts by weight of EVOH (A). .0005 to 0.1 parts by weight, preferably 0.001 to 0.05 parts by weight, particularly preferably 0.002 to 0.03 parts by weight. If the amount is too small, the content effect may not be sufficiently obtained. Conversely, if the amount is too large, it tends to be difficult to obtain a uniform film. In addition, when mix | blending 2 or more types of salts with EVOH (A), it is preferable that the total amount exists in the range of said compounding quantity.

Regarding a method of blending EVOH (A) with a heat stabilizer, for example, acetic acid, boron compound, acetate, and phosphate, for example, i) porosity of EVOH (A) having a water content of 20 to 80% by weight A method in which the precipitate is brought into contact with an aqueous solution of the additive, and the porous EVOH contains the additive and then dried; ii) the additive is contained in a uniform solution (water / alcohol solution, etc.) of EVOH (A) And then extruding it into a coagulation solution in the form of a strand, then cutting the resulting strand into pellets and further drying treatment; iii) EVOH (A) and additives are mixed together and extruded A method of melt kneading with a machine, etc .; iv) During the production of EVOH (A), the alkali (sodium hydroxide, potassium hydroxide, etc.) used in the saponification step is neutralized with an organic acid such as acetic acid and remains Acetic acid The amount of organic acid and by-product salt can be mentioned a method for adjusting the water washing treatment.
Among these, in order to obtain the effects of the present invention more remarkably, the methods i) and ii), which are excellent in the dispersibility of additives, and the method iv) are preferable when an organic acid and a salt thereof are contained.

<Chlorine resin>
In the resin composition of the present invention, the effect of obtaining a desired resin composition having a specific ultraviolet absorbing ability can be obtained by blending a small amount of a chlorine-based resin.
In this invention, the said effect is acquired by selecting chlorine-type resin as a compounding agent. This is because hydrochloric acid is generated from a chlorine-based resin by heating, and the hydrochloric acid appropriately decomposes EVOH, and purifies EVOH molecules having a polyene structure of an appropriate length in the main chain, thereby reducing the wavelength in a specific ultraviolet region. It is presumed that a resin composition having an absorption ability (for example, UV-C having a wavelength of less than 280 nm) can be obtained.
Since such a chlorine-based resin is a polymer, it has an advantage that there is no fear of bleeding out like a general ultraviolet absorber.

  The chlorinated resin used in the present invention is a polymer having a chlorine atom in the side chain, and examples thereof include polyvinyl chloride, polyvinylidene chloride, chlorinated polyethylene, and chlorinated polypropylene.

  Such a chlorinated resin is a compounding agent that is generally blended, for example, a plasticizer, a stabilizer, a lubricant, a filler, a coloring, within a range that does not impair the effects of the present invention (usually 30 wt% or less of the chlorinated resin). An agent, a flame retardant, etc. may be contained. In particular, a chlorine-based resin containing a plasticizer is called a soft vinyl chloride resin. On the other hand, a chlorine-based resin in which the compounding amount of these plasticizers and the like is low is called a hard vinyl chloride resin.

  In the present invention, it is preferable to use a hard vinyl chloride resin, that is, a chlorine-based resin having a low blending amount of the above blending agent. Since EVOH usually has abundant hydroxyl groups, it is considered that the compatibility with EVOH is higher when the chlorine-based resin contains an additive such as a plasticizer in advance. When the chlorinated resin that is not used is used, the effect of the present invention tends to be obtained more effectively. This is presumed that the compatibility with the EVOH resin tends not to be a problem because the blending amount of the chlorine-based resin described later is a specific small amount.

  The content of the chlorine-based resin is 0.001 to 1% by weight, preferably 0.005 to 0.5% by weight, and more preferably based on the total amount (weight basis) of EVOH and the chlorine-based resin. Is 0.007 to 0.3% by weight, more preferably 0.05 to 0.2% by weight. By setting the content of the chlorine-based resin in the above range, an ultraviolet absorption effect at a specific wavelength tends to be effectively obtained.

<Other thermoplastic resin (C)>
The resin composition of the present invention may contain other thermoplastic resin (C) as a resin component in addition to EVOH and chlorine-based resin. The content is usually 30 parts by weight or less, preferably 1 to 20% by weight, based on 100 parts by weight of EVOH.

  Specific examples of the other thermoplastic resin (C) include linear low density polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymer, ionomer, and ethylene-propylene. Copolymer, ethylene-α-olefin (α-olefin having 4 to 20 carbon atoms) copolymer, ethylene-acrylic acid ester copolymer, polypropylene, propylene-α-olefin (α-olefin having 4 to 20 carbon atoms) ) Broad carbonization such as copolymers, polybutenes, polypentenes or other olefins or copolymers, polycyclic olefins, or those olefins alone or copolymers grafted with unsaturated carboxylic acids or esters Hydrogen resin, polystyrene resin, polyester resin, polyamide, co-polymer Polyamide resins such as polyamide, acrylic resins, vinyl ester resins, polystyrene thermoplastic elastomers, polyester thermoplastic elastomers, thermoplastic elastomers such as polyurethane thermoplastic elastomers, polar group-modified polystyrene thermoplastic elastomers, polar group-modified polyester thermoplastics Examples thereof include thermoplastic resins such as polar group-modified thermoplastic elastomers such as elastomers and polar group-modified polyurethane thermoplastic elastomers. These may use multiple types together.

In particular, when a thermoplastic elastomer that does not contain a polar group or a resin composition that contains a polar group-modified thermoplastic elastomer is used as the other thermoplastic resin (C), it is preferable in terms of resistance to bending fatigue. These are preferably used in combination.
The weight ratio {EVOH / (thermoplastic elastomer not containing a polar group + polar group modified thermoplastic elastomer)} of the thermoplastic elastomer not containing a polar group and the polar group-modified thermoplastic elastomer relative to EVOH is usually 50 or more / less than 50 It is -99/1, Preferably it is 60 / 40-90 / 10. The weight ratio of the polar group-modified thermoplastic elastomer to the thermoplastic elastomer not containing the polar group (polar group-modified thermoplastic elastomer / thermoplastic elastomer containing no polar group) is usually 0.01 to 10, preferably 1 to 5. is there.
Furthermore, it is also preferable to have a hydrocarbon resin having a number average molecular weight of 100 to 3000 and a softening point of 60 ° C. or more and less than 170 ° C. When such a component is contained, its content rate {the hydrocarbon resin / (EVOH + thermoplastic elastomer containing no polar group + polar group-modified thermoplastic elastomer + the hydrocarbon resin)} is usually 0.5 to 10% by weight, preferably 1 to 5% by weight.

<Other additives>
In addition to the above components, the resin composition of the present invention, if necessary, within a range that does not impair the effects of the present invention (for example, less than 5% by weight of the entire resin composition), an inorganic filler, Plasticizers such as desiccants, oxygen absorbers, aliphatic polyhydric alcohols such as ethylene glycol, glycerin and hexanediol; saturated aliphatic amides (eg stearic acid amides), unsaturated fatty acid amides (eg oleic acid amides), Lubricants such as bis-fatty acid amide (for example, ethylene bis-stearic acid amide), low molecular weight polyolefin (for example, low molecular weight polyethylene having a molecular weight of about 500 to 10,000, or low molecular weight polypropylene), anti-blocking agent, antioxidant, coloring agent, antistatic Agent; ultraviolet absorber; antibacterial agent; insoluble inorganic salt (for example, hydrotalcite); filler (for example, Machine filler, etc.); surfactants, waxes; dispersing agent (e.g., calcium stearate, can be appropriately added known additives of monoglyceride stearate) and the like.

  The base resin in the entire resin composition of the present invention is EVOH. Therefore, the amount of EVOH is usually 70% by weight or more, preferably 80% by weight or more, and particularly preferably 90% by weight or more based on the entire resin composition. When the amount is too small, gas barrier properties tend to decrease.

<Method for preparing resin composition>
The resin composition of the present invention is prepared, for example, as follows. That is, EVOH and a chlorine-based resin may be blended, and a resin composition may be prepared by melt kneading or the like using a single or twin screw extruder or the like (melt kneading method). It may be dissolved and blended (solution mixing method), or each component may be dry blended at a predetermined ratio, for example, with a Banbury mixer (dry blending method).

  In addition, it is preferable to reduce the particle size of the chlorinated resin in advance by a known pulverization method. For this pulverization method, a known pulverizer such as a roller mill, a rotary mill or a hammer mill can be used, and freeze pulverization or low-temperature pulverization is preferably performed.

  The said melt kneading temperature is 150-300 degreeC normally, Preferably it is 170-250 degreeC. Of these, the dry blend method is preferred from the viewpoint of economy and productivity.

  The resin composition of the present invention is prepared by blending EVOH and a chlorine-based resin, preparing a composition (master batch) having a high chlorine-based resin concentration in advance, and blending such a composition (master batch) with EVOH. It is also possible to obtain a desired resin composition.

  In addition, when the resin composition is used as a pellet, the shape of the resin composition pellet includes, for example, a spherical shape, a cylindrical shape, a cubic shape, a rectangular parallelepiped shape, and the like, but usually in a spherical shape (oval shape) or a cylindrical shape. From the viewpoint of convenience when used as a molding material later, the size is usually 1 to 6 mm, preferably 2 to 5 mm, and the height is usually 1 to 6 mm, preferably 2 in the case of a spherical shape. In the case of a cylindrical shape, the diameter of the bottom surface is usually 1 to 6 mm, preferably 2 to 5 mm, and the length is usually 1 to 6 mm, preferably 2 to 5 mm.

  From the viewpoint of stabilizing the feed property at the time of melt molding, it is also preferable to attach a lubricant to the surface of the obtained resin composition pellets. The types of lubricants include higher fatty acids (for example, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, oleic acid, etc.), higher fatty acid metal salts (higher fatty acid aluminum salts, calcium salts, zinc salts, magnesium salts, Barium salts, etc.), higher fatty acid esters (methyl esters of higher fatty acids, isopropyl esters, butyl esters, octyl esters, etc.), higher fatty acid amides (saturated aliphatic amides such as stearic acid amide, behenic acid amide, oleic acid amide, erucic acid Unsaturated fatty acid amides such as amides, ethylene bis stearic acid amides, ethylene bis oleic acid amides, ethylene biserucic acid amides, bis fatty acid amides such as ethylene bis lauric acid amides), low molecular weight polyolefins (for example, molecular weights of about 500 to 10,000) Low part of Polyethylene, low molecular weight polypropylene, etc., or acid-modified products thereof), higher alcohols, ester oligomers, fluorinated ethylene resins, and the like, preferably higher fatty acids and / or metal salts, esters, and amides thereof. A higher fatty acid metal salt and / or a higher fatty acid amide is used.

  As the properties of the lubricant, any properties such as solid (powder, fine powder, flakes, etc.), semi-solid, liquid, paste, solution, emulsion (aqueous dispersion) can be used. However, in order to efficiently obtain the resin composition pellets of the present invention, an emulsion is preferable.

  As a method of attaching the lubricant to the surface of the resin composition pellets, a method of adhering the lubricant and the resin composition pellets by mixing them with a blender or the like, immersing the resin composition pellets in a lubricant solution or dispersion And a method of spraying a lubricant solution or dispersion on the resin composition pellets. Preferably, the resin composition pellets are charged into a blender or the like, and the emulsion lubricant is stirred, and the solid content of the lubricant is 0.001 to 1 part by weight / hr with respect to 100 parts by weight of the resin composition pellets. Further, gradually blending at a rate of 0.01 to 0.1 parts by weight / hr is preferable for uniform adhesion of the lubricant. Furthermore, in order to obtain a resin composition pellet in which all the lubricant adhered to the pellet surface is in close contact with the pellet surface and the lubricant is not liberated in the melt molding machine, the surface temperature of the resin composition pellet is set as described above. The most preferable method is a method of bringing the lubricant into contact with the lubricant at a high temperature of -50 ° C or higher and lower than the melting point of the EVOH.

  The content of the lubricant is preferably 10 to 1000 ppm, more preferably 20 to 500 ppm, and particularly preferably 50 to 250 ppm with respect to the resin composition pellets, from the viewpoint of stabilizing the feed property during melt molding.

<Melformed product>
The resin composition of the present invention can be molded into various melt-molded products such as films, cups, bottles, and the like by a melt molding method. Examples of the melt molding method include extrusion molding methods (T-die extrusion, inflation extrusion, blow molding, melt spinning, profile extrusion, etc.), injection molding methods, and the like. The melt molding temperature is usually appropriately selected from the range of 150 to 300 ° C.
In the present invention, “film” is not particularly distinguished from “sheet” and “tape”, but is described as meaning including these.

When a melt-molded product is obtained from the resin composition of the present invention, a melt-molded product may be obtained by melt-molding the resin composition obtained by the dry blend using an extruder or the like, or the melt-kneading product described above. A pellet made of a resin composition may be prepared by the above, and this may be subjected to a melt molding method to obtain a melt molded product. In the present invention, from the viewpoint of economy, a method of obtaining a melt-molded product by melt-molding a resin composition obtained by dry blending using an extruder or the like is preferable.
A melt-molded product obtained by melt-molding the above resin composition tends to obtain the effects of the present invention more efficiently.

  The melt-molded product containing the resin composition of the present invention may be used for various applications as it is. At this time, the thickness of the layer of the resin composition (in the case of producing a film as a single layer) is usually 1 to 5000 μm, preferably 5 to 4000 μm, and particularly preferably 10 to 3000 μm.

  In addition, the layer of the resin composition (in the case of producing a film as a single layer) contains a small amount of EVOH and a chlorine-based resin. The layer of the resin composition is a layer formed from the resin composition obtained as described above, and is usually obtained by performing melt molding as described above. The content of the chlorine-based resin relative to the total amount of the EVOH and the chlorine-based resin can be quantified by, for example, measuring by ionization chromatography analysis using a resin composition.

<Multilayer structure>
The multilayer structure of the present invention has at least one layer composed of the resin composition of the present invention. A layer composed of the resin composition of the present invention (hereinafter simply referred to as “resin composition layer” refers to a layer composed of the resin composition of the present invention) is laminated with another substrate to further increase the strength. Can be increased or other functions can be added.

  As the substrate, a thermoplastic resin other than EVOH (hereinafter referred to as “other thermoplastic resin”) is preferably used.

When the resin composition layer of the present invention is a (a1, a2,...) And the other thermoplastic resin layers are b (b1, b2,. 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. Any combination is possible. In addition, when R is a recycled layer containing a mixture of the resin composition of the present invention and a thermoplastic resin, which is obtained by remelt molding an edge portion or a defective product generated in the process of producing the multilayer structure, 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. It is also possible. The number of layers of the multilayer structure of the present invention is usually 2 to 15 layers, preferably 3 to 10 layers in total.
In the above layer structure, an adhesive resin layer may be interposed between the respective layers as necessary.

  In the multilayer structure of the present invention, the multilayer structure preferably includes the resin composition layer of the present invention as an intermediate layer, and a multilayer in which other thermoplastic resin layers are provided as both outer layers of the intermediate layer. A multilayer structure including a unit of structure (b / a / b or b / adhesive resin layer / a / adhesive resin layer / b) as a basic unit and at least the basic unit as a structural unit is preferable.

  Examples of the other thermoplastic resins include linear low-density polyethylene, low-density polyethylene, ultra-low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-propylene (block and random) copolymers, and ethylene-α. -Polyethylene resins such as olefin (α-olefin having 4 to 20 carbon atoms) copolymer, polypropylene resins such as polypropylene and propylene-α-olefin (α-olefin having 4 to 20 carbon atoms) copolymer, polybutene (Unmodified) polyolefin resins such as polypentene and polycyclic olefin resins (polymers having a cyclic olefin structure in the main chain and / or side chain), and these polyolefins grafted with unsaturated carboxylic acids or esters thereof Modified unsaturated carboxylic acid modified polyolefin resin, etc. Broadly defined polyolefin resins including modified olefin resins, ionomers, ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, ethylene-acrylic acid ester copolymers, polyester resins, polyamide resins (copolymerized polyamides) ), Polyvinyl chloride, polyvinylidene chloride, acrylic resins, polystyrene resins, vinyl ester resins, polyester thermoplastic elastomers, thermoplastic elastomers such as polyurethane thermoplastic elastomers, halogens such as chlorinated polyethylene and chlorinated polypropylene Polyolefins, aromatic or aliphatic polyketones.

  Among these, in consideration of hydrophobicity, polyamide resins, polyolefin resins, polyester resins, and polystyrene resins, which are hydrophobic resins, are preferable, and polyethylene resins, polypropylene resins, and polycyclic olefins are more preferable. Polyolefin resins such as these and other unsaturated carboxylic acid-modified polyolefin resins, and in particular, polycyclic olefin resins are preferably used as hydrophobic resins.

  Moreover, as adhesive resin which is the said adhesive resin layer forming material, a well-known thing can be used, if it selects suitably according to the kind of thermoplastic resin used for the other thermoplastic resin (b) used as a base material. Good. A typical example is a modified polyolefin polymer containing a carboxyl group obtained by chemically bonding an unsaturated carboxylic acid or its anhydride to a polyolefin resin by an addition reaction or a graft reaction. For example, maleic anhydride graft-modified polyethylene, maleic anhydride graft-modified polypropylene, maleic anhydride graft-modified ethylene-propylene (block and random) copolymer, maleic anhydride graft-modified ethylene-ethyl acrylate copolymer, maleic anhydride graft Examples thereof include a modified ethylene-vinyl acetate copolymer, a maleic anhydride-modified polycyclic olefin resin, a maleic anhydride graft-modified polyolefin resin, and the like. These can be used alone or in combination of two or more.

  In the other thermoplastic resin (base resin) and adhesive resin layer, a conventionally known plasticizer may be used within a range not impairing the gist of the present invention (for example, 30% by weight or less, preferably 10% by weight or less). , Fillers, clays (montmorillonite, etc.), colorants, antioxidants, antistatic agents, lubricants, core materials, antiblocking agents, ultraviolet absorbers, waxes and the like.

  The lamination method in the case where a multilayer structure is produced by laminating the resin composition of the present invention with another substrate (other thermoplastic resin) (including the case where an adhesive resin layer is interposed) is a known method. Can be done. For example, a method of melt extrusion laminating another substrate to the film, sheet or the like of the resin composition of the present invention, conversely, a method of melt extrusion laminating the resin composition of the present invention to another substrate, the resin composition of the present invention A film (layer) and another substrate (layer) comprising the resin composition of the present invention, and an organic titanium compound, an isocyanate compound, and a polyester compound. And a method of dry laminating using a known adhesive such as a polyurethane compound, a method of removing the solvent after coating the solution of the resin composition of the present invention on another substrate, and the like. Among these, the co-extrusion method is preferable from the viewpoint of cost and environment.

  The multilayer structure is then subjected to (heating) stretching treatment as necessary. The stretching treatment may be either uniaxial stretching or biaxial stretching, and in the case of biaxial stretching, it may be simultaneous stretching or sequential stretching. As the stretching method, a roll stretching method, a tenter stretching method, a tubular stretching method, a stretching blow method, a vacuum / pressure forming method, or the like having a high stretching ratio can be employed. The stretching temperature is usually selected from the range of about 40 to 170 ° C, preferably about 60 to 160 ° C. If the stretching temperature is too low, the stretchability becomes poor, and if it is too high, it becomes difficult to maintain a stable stretched state.

  For the purpose of imparting dimensional stability after stretching, heat setting may then be performed. The heat setting can be carried out by a known means. For example, the stretched multilayer structure (stretched film) is usually 80 to 180 ° C., preferably 100 to 165 ° C., usually for about 2 to 600 seconds while maintaining a tension state. Heat treatment is performed.

  Moreover, when using the multilayer stretched film obtained using the resin composition of this invention as a film for shrink, in order to provide heat shrinkability, it does not perform said heat setting, for example, the film after extending | stretching It is sufficient to perform a process such as cooling and fixing by applying cold air to the surface.

  Furthermore, depending on the case, it is also possible to obtain a cup or a tray-like multilayer container from the multilayer structure of the present invention. As a method for producing the multi-layer container, usually a drawing method is employed, and specifically, a vacuum forming method, a pressure forming method, a vacuum / pressure forming method, a plug assist type vacuum / pressure forming method and the like can be mentioned. Furthermore, when a tube or bottle-shaped multi-layer container is obtained from a multi-layer parison (a hollow tubular preform before blow), a blow molding method is adopted, specifically, an extrusion blow molding method (double-head type, mold transfer type). , Parison shift type, rotary type, accumulator type, horizontal parison type, etc.), cold parison type blow molding method, injection blow molding method, biaxial stretch blow molding method (extruded cold parison biaxial stretch blow molding method, injection type) Cold parison biaxial stretch blow molding method, injection molding inline biaxial stretch blow molding method, etc.). The multilayer laminate of the present invention is optionally subjected to heat treatment, cooling treatment, rolling treatment, printing treatment, dry lamination treatment, solution or melt coating treatment, bag making processing, deep drawing processing, box processing, tube processing, split processing, etc. Can be done.

  The thickness of the multilayer structure (including stretched ones) of the present invention, and the thickness of the resin composition layer, other thermoplastic resin layer and adhesive resin layer constituting the multilayer structure are the layer composition, thermoplastic resin The type of adhesive resin, the type of adhesive resin, the application and packaging form, the required physical properties, and the like are set as appropriate. In addition, the following numerical value is a total value of the thickness of the same kind of layer when there are two or more kinds of resin composition layers, adhesive resin layers, and other thermoplastic resin layers. is there.

  The thickness of the multilayer structure of the present invention (including the stretched structure) is usually 10 to 5000 μm, preferably 30 to 3000 μm, particularly preferably 50 to 2000 μm. When the total thickness of the multilayer structure is too thin, the gas barrier property may be lowered. Further, when the total thickness of the multilayer structure is too thick, the gas barrier property becomes excessive performance, and unnecessary raw materials tend to be used, which tends to be uneconomical. The resin composition layer is usually 1 to 500 μm, preferably 3 to 300 μm, particularly preferably 5 to 200 μm, and the other thermoplastic resin layer is usually 5 to 30000 μm, preferably 10 to 20000 μm, particularly preferably 20 The adhesive resin layer is usually 0.5 to 250 μm, preferably 1 to 150 μm, and particularly preferably 3 to 100 μm.

  Furthermore, the ratio of the thickness of the resin composition layer to the other thermoplastic resin layer in the multilayer structure (resin composition layer / other thermoplastic resin layer) is the thickness of the thickest layers when there are a plurality of layers. The ratio is usually 1/99 to 50/50, preferably 5/95 to 45/55, particularly preferably 10/90 to 40/60. Further, the thickness ratio of the resin composition layer to the adhesive resin layer in the multilayer structure (resin composition layer / adhesive resin layer) is usually 10 by the ratio of the thickest layers when there are a plurality of layers. / 90 to 99/1, preferably 20/80 to 95/5, particularly preferably 50/50 to 90/10.

  Containers and lids made of bags and cups made of stretched films, trays, tubes, bottles, etc., as described above, as well as seasonings such as mayonnaise and dressing, miso, etc. It is useful as a container for various packaging materials for fermented foods, fats and oils such as salad oil, beverages, cosmetics, and pharmaceuticals.

  Among them, the layer composed of the resin composition of the present invention is excellent in coloration suppression even when a large number of heat histories are applied due to multiple times of melt molding or the like, so that seasonings of general foods, mayonnaise, dressings, etc. It is useful as various containers such as foods, fermented foods such as miso, fats and oils such as salad oil, soups, beverages, cosmetics, pharmaceuticals, detergents, cosmetics, industrial chemicals, agricultural chemicals, and fuels. Especially semi-solid foods and seasonings such as mayonnaise, ketchup, sauce, miso, wasabi, mustard, grilled meat, etc., salad oil, mirin, sake, beer, wine, juice, tea, sports drink, mineral water, milk Bottles and tubes for liquid beverages and seasonings such as fruits, jelly, pudding, yogurt, mayonnaise, miso, processed rice, cooked foods, cups for seasonings It is particularly useful as a packaging material such as a wide container for raw containers, raw meat, processed meat products (ham, bacon, wiener, etc.), cooked rice, and pet food.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In the examples, “parts” are based on weight.

[Evaluation item]
<Gas barrier properties>
Using a film having a thickness of 30 μm, the oxygen permeability (23 ° C., relative humidity 65%) was measured using an oxygen gas permeation measuring device (manufactured by Mocon, OX-TRAN 2/20).

<Ultraviolet transmittance>
Using the obtained film, using a spectrophotometer “UV2550” manufactured by Shimadzu Corporation, transmittance (%) at a wavelength of 250 nm (ultraviolet region) and transmittance (%) at a wavelength of 500 nm (visible light region) It was measured.

[Production of resin composition]
EVOH, saponified ethylene-vinyl acetate copolymer [content of ethylene structural unit 29 mol%, MFR 4.0 g / 10 min (210 ° C., load 2160 g), saponification degree 99.7 mol%] 90 parts, Hydrogenation block copolymer of styrene-butadiene-styrene block copolymer [SEBS, MFR 5 g / 10 min (230 ° C., 2160 g)] 7.6 parts, hydrogenation of carboxyl group-modified styrene-butadiene-styrene block copolymer Molten block copolymer [MFR4, 5 g / 10 min (230 ° C., 2160 g) 1.2 parts, acid value 2 mg: CH ₃ ONa / g], 1.2 parts alicyclic hydrocarbon resin (Alcon P125) Using 99.99 parts of the resin composition pellets obtained by kneading, using 0.01 parts of soft vinyl chloride resin as the chlorine resin, It was de.
In addition, this chlorinated resin used what was reduced in size by freeze-grinding in advance.

A film having a thickness of 30 μm was formed from the resin composition under the following conditions.
Screw: Full flight type Screen mesh: 90/120/90
Screw diameter: 40 mmφ
L / D: 28
Screw compression ratio: 3.4
Die: Coat hanger die Extruder barrel temperature: C1 / C2 / C3 / C4 / H / D = 180/200/220/220/220/220 ° C.
Rotation speed: 20rpm
Discharge rate: 4kg / hr
The above-mentioned evaluation was performed about the obtained film. The results are shown in Table 1.

[Example 2]
In Example 1, a film having a thickness of 30 μm was similarly obtained except that 99.9 parts of the resin composition pellets were used and 0.1 part of a soft vinyl chloride resin was used as the chlorinated resin, and the same evaluation was performed. The results are shown in Table 1.

[Example 3]
In Example 1, a film having a thickness of 30 μm was similarly obtained except that a hard vinyl chloride resin was used as the chlorine-based resin, and the same evaluation was performed. The results are shown in Table 1.

[Comparative Example 1]
In Example 1, a film having a thickness of 30 μm was similarly obtained except that no chlorine-based resin was used, and the same evaluation was performed. The results are shown in Table 1.

[Table 1]

  In Comparative Example 1 in which no chlorine-based resin was blended, the transmittance in the visible light region at a wavelength of 500 nm was very good at 98%, and 41% at a wavelength of 250 nm corresponding to UV-C. On the other hand, in the Example using the resin composition of this invention, it turns out that the transmittance | permeability of the visible region is as good as 98%, which is 98%. On the other hand, it can be seen that at a wavelength of 250 nm, the transmittance is lower than that of Comparative Example 1, and ultraviolet absorption ability is obtained. Particularly in Example 3, the transmittance at a wavelength of 250 nm was the lowest and showed a good value.

  On the other hand, in the gas barrier property evaluation, both of the comparative examples were excellent at the same level. That is, it can be seen that when the resin composition of the present invention is used, that is, even when a chlorine-based resin is blended with EVOH, excellent gas barrier properties similar to those when not blended are obtained.

  Therefore, the melt-molded product obtained from the resin composition of the present invention has excellent transparency and gas barrier properties, and has an ability to absorb a wavelength in a specific ultraviolet region (for example, UV-C having a wavelength of less than 280 nm). It is clear.

  Since the resin composition of the present invention has excellent transparency and gas barrier properties, a melt-molded product having an absorption ability of a wavelength in a specific ultraviolet region (for example, UV-C having a wavelength of less than 280 nm) can be obtained. It is particularly useful as a film or sheet as a food packaging material, a pharmaceutical packaging material, an industrial chemical packaging material, a chemical packaging material such as an agrochemical packaging material, or a container such as a bottle.

Claims (4)

  An ethylene-vinyl ester copolymer saponified resin composition having an ultraviolet transmittance of 40% or less at a wavelength of 250 nm and 95% or more at a wavelength of 500 nm when the thickness is 30 μm.   The ethylene-vinyl ester copolymer saponified resin composition according to claim 1 contains a chlorine resin, and the content thereof is based on the total amount of the ethylene-vinyl ester copolymer saponified product and the chlorine resin. A resin composition characterized by being 0.001 to 1% by weight.   A melt-molded product obtained by melt-molding the resin composition according to claim 1.   A multilayer structure having at least one layer comprising the resin composition according to claim 1.