JP6572557B2 - Resin composition - Google Patents

Description

  The present invention relates to a resin composition containing a saponified modified ethylene-vinyl ester copolymer (hereinafter sometimes referred to as “modified EVOH”) grafted with an aliphatic polyester and a boron compound. The present invention relates to a resin composition excellent in extrusion moldability.

  Saponified ethylene-vinyl acetate ester copolymer (hereinafter sometimes abbreviated as “EVOH”) has a very strong intermolecular force due to hydrogen bonding between hydroxyl groups present in the polymer side chain. . Therefore, since the crystallinity is high and the intermolecular force is high even in the amorphous part, gas molecules and the like cannot pass through the film using EVOH. For these reasons, a film using EVOH exhibits excellent gas barrier properties.

  Films using EVOH are used by being formed into films and sheets such as food packaging materials, pharmaceutical packaging materials, industrial chemical packaging materials, agricultural chemical packaging materials, or containers such as bottles, etc., utilizing their excellent gas barrier properties. Has been.

In general, when EVOH is molded, resin pellets are usually put into an extruder or the like and formed into a film or sheet by melt molding. Depending on the properties of such EVOH pellets, extrudability Is insufficient, the accuracy of the shape and thickness of the target EVOH molded product may be lowered.
Therefore, in order to improve the extrusion moldability, a technique for blending a boron compound with EVOH has been proposed (for example, see Patent Document 1).
The technology disclosed in the above patent document improves extrusion moldability by blending a boron compound into EVOH pellets and increasing the melt tension of EVOH.

By the way, EVOH is a hard and brittle resin and has a drawback of lacking flexibility. For this reason, when it is used as a packaging material or a molding material, if it is repeatedly bent and used, cracks and pinholes are generated due to bending fatigue and the excellent performance cannot be maintained.
As EVOH imparted with flexibility to solve such problems, an aliphatic polyester, for example, modified EVOH grafted with ε-caprolactone has been proposed (see, for example, Patent Document 2).

JP 11-035771 A JP-A-9-208638

  However, the technology combining EVOH and a boron compound disclosed in Patent Document 1 may be obtained due to the recent advancement of technology, depending on the properties of such resin pellets, the extrusion moldability may be insufficient. The accuracy of the shape and thickness of the molded product may be lowered, and further improvement is desired.

  In view of this, the present invention has an object of providing a resin composition that is excellent in extrusion moldability when melt-extruding EVOH.

  As a result of intensive studies in view of the above circumstances, the present inventor has found that by adding a predetermined amount of boron compound to the modified EVOH, the rate of increase in melt tension is improved and the extrudability is excellent. completed.

  That is, the present invention is a resin composition containing a modified EVOH (A) grafted with an aliphatic polyester and a boron compound (B), wherein the boron compound (B) content is relative to the modified EVOH (A). The resin composition is 1 to 150 ppm in terms of boron.

  In the present invention, in the case of modified EVOH, the boron compound usually interacts with the carbonyl group in caprolactone in the modified EVOH because of the electronic state of oxygen. In addition, similar to general unmodified EVOH, it has been found that the melt tension is increased by interacting with the hydroxyl group in EVOH.

The resin composition of the present invention has the effect that the rate of increase in melt tension is improved and the extrusion moldability is excellent.
In general, when the take-up speed in extrusion molding is increased, if the rate of increase in melt tension is low, neck-in tends to occur and the film width becomes narrow. However, if the increase rate of the melt tension is large, even if the take-up speed is increased, the neck width does not occur, and the film width can be maintained, so that the extrusion moldability is excellent. Very important.

  Hereinafter, although it demonstrates in detail about the structure of this invention, these show an example of a desirable embodiment and are not specified by these content.

  The resin composition of the present invention is a resin composition containing a modified EVOH (A) and a boron compound (B), and the content of the boron compound (B) is in terms of boron relative to the modified EVOH (A). It is characterized by being 1-150 ppm.

<Description of Modified EVOH (A)>
The modified EVOH (A) of the present invention only needs to be grafted with an aliphatic polyester. For example, lactones are subjected to ring-opening polymerization in the presence of EVOH (a) to form an aliphatic polyester. It can be produced by a grafting method (hereinafter sometimes abbreviated as “ring-opening / grafting reaction”). The formation of the aliphatic polyester by the ring-opening / grafting reaction starts with the hydroxyl group of EVOH (a) as the starting terminal.

  Hereinafter, the ring-opening / grafting reaction of lactones in the presence of EVOH (a) will be described in detail.

[EVOH (a)]
First, EVOH (a) which is a raw material of the modified EVOH (A) of the present invention will be described.
EVOH (a) 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. The vinyl ester monomer is generally vinyl acetate from the economical aspect. 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 (a) mainly comprises an ethylene structural unit and a vinyl alcohol structural unit, and includes a slight amount of vinyl ester structural unit remaining without being saponified.

The content of ethylene structural units in EVOH (a) used in the present invention is usually 20 to 60 mol%, preferably 25 to 50 mol%, particularly preferably 29 to 45 mol%. When the content is too low, the flexibility tends to decrease, and when it is too high, the gas barrier property tends to decrease.
The content rate of the ethylene structural unit can be measured according to, for example, ISO 14663.

The degree of saponification of the vinyl ester component in EVOH (a) is usually 90 to 100 mol%, preferably 95 to 99.99 mol%, particularly preferably 99 to 99.99 mol%. When the degree of saponification is too low, flexibility tends to decrease.
The saponification degree of the vinyl ester component can be measured according to, for example, JIS K6726 (however, EVOH is a solution uniformly dissolved in water / methanol solvent).

  The melt flow rate (MFR) (210 ° C., load 2,160 g) of EVOH (a) is usually 1 to 50 g / 10 minutes, preferably 1.5 to 25 g / 10 minutes, particularly preferably 2 to 20 g / minute. 10 minutes. If the MFR is too large, the barrier property tends to decrease, and if it is too small, the flexibility tends to decrease.

  As the EVOH (a), as long as the average value is a combination that satisfies the above requirements, two or more types of EVOH having different ethylene content, saponification degree, and MFR may be mixed and used.

  The EVOH (a) used in the present invention may further contain structural units derived from the following comonomer. The comonomer is an α-olefin such as propylene, isobutene, α-octene, α-dodecene, α-octadecene, 3-buten-1-ol, 4-penten-1-ol, 3-butene-1, 2-diol. Hydroxyl group-containing α-olefins such as hydroxy group-containing α-olefin derivatives such as esterified products and acylated products, unsaturated carboxylic acids or salts thereof, partial alkyl esters, complete alkyl esters, nitriles, amides, anhydrides, It is a comonomer such as saturated sulfonic acid or a salt thereof, a vinyl silane compound, vinyl chloride, or styrene.

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

  Among the modified products as described above, EVOH in which a primary hydroxyl group is introduced into a side chain by copolymerization is preferable from the viewpoint of good secondary formability such as stretching treatment and vacuum / pressure forming, among which 1,2- EVOH having a diol structure in the side chain is preferred.

[Lactones]
The lactone is not particularly limited as long as it is a lactone having 3 to 10 carbon atoms constituting a ring forming an aliphatic polyester by ring-opening polymerization. Such lactones are represented by the following general formula when they have no substituent, and n is an integer of 2 to 9. Preferably, n is 4-5. In addition, any carbon atom of the alkylene chain — (CH ₂ ) n — in the following formula has at least one lower alkyl group having about 1 to 8 carbon atoms, a lower alkoxy group, a cycloalkyl group, a phenyl group. And having a substituent such as an aralkyl group.

  Specific examples include β-propiolactones, γ-butyrolactones, ε-caprolactones, δ-valerolactones, and the like.

  Examples of β-propiolactones include β-propiolactone and dimethylpropionlactone.

  Examples of γ-butyrolactones include butyrolactone, γ-valerolactone, γ-caprolactone, γ-caprolactone, γ-laurolactone, γ-palmilactone, γ-stearolactone, crotonolactone, and α-angelica. Examples include lactone and β-angelica lactone.

  Examples of ε-caprolactones include monoalkyl-ε-, such as ε-caprolactone, monomethyl-ε-caprolactone, monoethyl-ε-caprolactone, monodecyl-ε-caprolactone, monopropyl-ε-caprolactone, monodecyl-ε-caprolactone, and the like. Caprolactone; dialkyl-ε-caprolactone in which two alkyl groups are substituted on carbon atoms other than the ε position; trialkyl-ε-caprolactone in which three alkyl groups are substituted on carbon atoms other than the ε position. Alkoxy-ε-caprolactone such as ethoxy-ε-caprolactone; cycloalkyl-lactone such as cyclohexyl-ε-caprolactone; aralkyl-ε-caprolactone such as benzyl-ε-caprolactone; aryl-ε such as phenyl-ε-caprolactone; Caprolactone, and the like.

  Examples of δ-valerolactones include 5-valerolactone, 3-methyl-5-valerolactone, 3,3-dimethyl-5-valerolactone, 2-methyl-5-valerolactone, and 3-ethyl-5- Examples include valerolactone.

  These lactones can be used alone or in combination of two or more.

  Among these, as the lactone used in the present invention, ε-caprolactone or δ-valerolactone is preferable from the viewpoint of reactivity, and ε-caprolactone is more preferable from the viewpoint of being inexpensive and easily available. .

<Method for producing modified EVOH (A)>
The ring-opening / grafting reaction of lactones in the presence of EVOH (a) is usually performed, for example, in a molten state of EVOH (a). For example, heating and stirring are performed in a stirring tank type manufacturing apparatus having a stirring blade. While using an extruder or the like, a method using a stirring tank type production apparatus that can easily control the reaction time is preferably used.
The preparation of each material may be performed sequentially or mixed in advance. Among them, a method of first charging EVOH (a) and charging a lactone having a ring-opening / graft reaction catalyst dissolved therein is most preferable. The lactones and the catalyst are preferably charged by a method in which EVOH (a) is stirred.

  The amount of lactones used relative to EVOH (a) may be appropriately selected so as to obtain the desired grafted aliphatic polyester unit content, but is usually 1 to 100 parts by weight of EVOH (a). 200 parts by weight, preferably 10 to 150 parts by weight, particularly preferably 20 to 100 parts by weight. If the amount used is too small, the flexibility tends to decrease, whereas if the amount used is too large, the gas barrier property tends to decrease.

As the catalyst for the ring-opening / grafting reaction, those conventionally known as ring-opening polymerization catalysts for lactones can be used. For example, a titanium compound, a tin compound, etc. can be mentioned. Specific examples include titanium alkoxides such as tetra-n-butoxy titanium, tetraisobutoxy titanium, and tetraisopropoxy titanium, tin alkoxides such as dibutyl dibutoxy tin, and tin ester compounds such as dibutyl tin diacetate. Of these, tetra-n-butoxytitanium is preferred because it is inexpensive and easily available.
The amount of the catalyst used is usually 0.01 to 1 part by weight, preferably 0.03 to 0.5 part by weight, particularly preferably 0.05 to 0.3 part by weight, based on 100 parts by weight of the lactone. is there. If the amount used is too small or too large, the modification rate tends to decrease.

  The reaction temperature in the ring-opening / grafting reaction is usually 50 to 250 ° C., preferably 100 to 240 ° C., and more preferably 150 to 230 ° C. in a molten state. If the reaction temperature is too high, the modified EVOH (A) tends to thermally deteriorate. On the other hand, when the reaction temperature is too low, the ring opening / grafting reaction of EVOH (a) does not easily proceed and the modification tends to be difficult.

  The temperature at the time of charging each material in the ring-opening / grafting reaction is usually room temperature, for example, 10 to 40 ° C.

  The temperature at the time of charging each material in the graft reaction is usually room temperature, for example, 10 to 40 ° C.

  The rate of temperature rise after adding lactones and a catalyst to EVOH (a) is usually 0.1 to 50 ° C./min, preferably 0.15 to 10 ° C./min° C., more preferably Is 0.2 to 5 ° C./min. When the rate of temperature increase is too high, the ring opening / grafting reaction of EVOH (a) does not proceed easily and tends to be unmodified. On the other hand, when the rate of temperature increase is too low, the modified EVOH (A) tends to be thermally deteriorated.

  The reaction time in the ring-opening / grafting reaction is usually 10 seconds to 24 hours, preferably 1 minute to 15 hours, and more preferably 30 minutes to 6 hours. If the reaction time is too long, the modified EVOH (A) tends to thermally deteriorate. On the other hand, if the reaction time is too short, the ring opening / grafting reaction of EVOH (a) does not proceed easily and tends to be unmodified.

  The production apparatus is not particularly limited, and for example, a vertical stirring production apparatus having a stirring blade, a horizontal stirring production apparatus having a single or biaxial stirring blade, an extruder, and the like can be used.

  Examples of the stirring blade include a double helical ribbon blade, a single helical ribbon blade, a screw blade, a V-shaped blade, a propeller blade, a turbine blade, and an anchor blade. Among these, a double helical ribbon blade is preferable from the viewpoint of stirring efficiency.

  The rotation speed of the stirring blade is usually 1 to 200 rpm, preferably 3 to 100 rpm, and more preferably 5 to 80 rpm. If the rotational speed is too fast, the graft reaction tends to be non-uniform. On the other hand, if the rotational speed is too slow, the graft reaction tends to be non-uniform.

  The ring-opening / grafting reaction is preferably carried out under a nitrogen stream in order to prevent the modified EVOH (A) from deteriorating.

After the ring-opening / grafting reaction, it is preferable to remove unreacted monomers in order to prevent odor. Examples of the method for removing the unreacted monomer include a method of immersing in a solution in which the unreacted monomer is dissolved and a method for removing under reduced pressure. From the viewpoint of production efficiency, a method of removing under reduced pressure is preferable.
For example, the conditions for removing the reduced pressure are the same set temperature as the reaction temperature, 1 second to 10 hours, and 100 to 101200 Pa.

  As a method for taking out the modified EVOH (A) from the production apparatus after the ring-opening / grafting reaction, for example, a method of conveying by pressurizing the inside of the production apparatus, a method of conveying by the dead weight of the modified EVOH (A), and a pump However, from the viewpoint of production efficiency, a method of pressurizing the inside of the manufacturing apparatus is preferable.

  Thus, modified EVOH (A) is obtained. The ethylene content in the obtained modified EVOH (A) is usually 20 to 60 mol%, preferably 25 to 50 mol%, particularly preferably 29 to 45. Mol%. When the content is too low, the flexibility tends to decrease, and when it is too high, the gas barrier property tends to decrease.

  The saponification degree in the obtained modified EVOH (A) is usually 90 to 100 mol%, preferably 95 to 99.99 mol%, particularly preferably 99 to 99.99 mol%. When the degree of saponification is too low, flexibility tends to decrease.

  The MFR (210 ° C., load 2,160 g) in the obtained modified EVOH (A) is usually 1 to 50 g / 10 minutes, preferably 1.5 to 25 g / 10 minutes, particularly preferably 2 to 20 g. / 10 minutes. If the MFR is too large, the barrier property tends to decrease, and if it is too small, the flexibility tends to decrease.

The content of EVOH (a) units forming a trunk in the obtained modified EVOH (A) is usually 40 to 99% by weight, preferably 45 to 95% by weight, particularly preferably 50 to 90% by weight. The content of the aliphatic polyester unit grafted on the trunk is usually 1 to 60% by weight, preferably 5 to 55% by weight, and particularly preferably 10 to 50% by weight. When the content of the EVOH (a) unit is too high, the flexibility tends to decrease. On the other hand, when the content of the EVOH (a) unit is too low, the gas barrier property tends to decrease.
The content of EVOH units in the modified EVOH (A) and the content of grafted aliphatic polyester units can be calculated from ¹ H-NMR measurement results.

  The modification rate in the obtained modified EVOH (A) is usually 0.1 to 30 mol%, more preferably 1 to 20 mol%, and particularly preferably 5 to 15 mol%. Such a modification rate means the proportion of EVOH (a) structural units grafted with an aliphatic polyester having a hydroxyl group as a terminal group. If the modification rate in the modified EVOH (A) is too low, the flexibility tends to decrease, whereas if the modification rate in the modified EVOH (A) is too high, the gas barrier property tends to decrease.

The average chain length of the aliphatic polyester unit in the obtained modified EVOH (A) is usually 1 to 3 mol, preferably 1 to 2.5 mol, and particularly preferably 1 to 2 mol. If the average chain length of the aliphatic polyester unit is too long, the gas barrier property tends to decrease.
The average chain length of the aliphatic polyester unit in the modified EVOH (A) can be calculated from the ¹ H-NMR measurement result.

The number average molecular weight (in terms of standard polystyrene measured by GPC) of the obtained modified EVOH (A) is usually 10,000 to 300,000, preferably 12,500 to 200,000, particularly preferably 15,000 to 100,000. If the number average molecular weight of the modified EVOH (A) is too high, the barrier property tends to be lowered. On the other hand, if the number average molecular weight of the modified EVOH (A) is too low, the flexibility tends to be lowered.
The number average molecular weight in the modified EVOH (A) can be calculated from the GPC measurement result.

As melting | fusing point of obtained modified EVOH (A), it is 50-190 degreeC normally, Preferably it is 60-160 degreeC, Especially preferably, it is 70-120 degreeC. If the melting point of the modified EVOH (A) is too high, the flexibility tends to be lowered. On the other hand, if the melting point of the modified EVOH (A) is too low, the barrier property tends to be lowered.
In general, grafting of an aliphatic polyester weakens intermolecular forces such as hydrogen bonding between hydroxyl groups in the EVOH (a) of the skeleton. Therefore, when the modification rate in the modified EVOH (A) increases, the modified EVOH ( The melting point of A) tends to be low.
In addition, melting | fusing point of said modified | denatured EVOH (A) can be measured using a differential scanning calorimeter.

  In the modified EVOH (A) used in the present invention, a compounding agent generally incorporated into EVOH, for example, a heat stabilizer, an antioxidant, in a range that does not inhibit the effects of the present invention (for example, 5% by weight or less of the resin composition) Agent, antistatic agent, colorant, UV absorber, lubricant, plasticizer, light stabilizer, surfactant, antibacterial agent, desiccant, antiblocking agent, flame retardant, crosslinking agent, curing agent, foaming agent, crystal nucleus Agents, antifogging agents, biodegradable additives, silane coupling agents, oxygen absorbers and the like may be contained.

Examples of the heat stabilizer include organic acids such as acetic acid, propionic acid, butyric acid, lauric acid, stearic acid, oleic acid, and behenic acid or the like for the purpose of improving various physical properties such as heat stability during melt molding. Alkali metal salts (sodium, potassium, etc.), alkaline earth metal salts (calcium, magnesium, etc.), zinc salts, etc .; or inorganic acids such as sulfuric acid, sulfurous acid, carbonic acid, phosphoric acid, or alkali metal salts thereof You may contain additives, such as salts, such as (sodium, potassium, etc.), alkaline-earth metal salts (calcium, magnesium, etc.), and zinc salts.
Moreover, you may use these additives 1 type or in mixture of 2 or more types.
Among these, it is particularly preferable to contain acetic acid, acetate, and phosphate.

  When acetic acid is contained, the content is usually 0.001 to 1 part by weight, preferably 0.005 to 0.2 part by weight, particularly preferably 0.01 to 100 parts by weight of the modified EVOH (A). 0.1 parts by weight. If the content of acetic acid is too small, there is a tendency that the effect of acetic acid content is not sufficiently obtained. Conversely, if the content is too large, it tends to be difficult to obtain a uniform film.

  The content of acetate and phosphate (including hydrogen phosphate) is usually in metal conversion (analyzed by ICP emission spectrometry after ashing) with respect to 100 parts by weight of modified EVOH (A). 0.0005 to 0.1 part by weight, preferably 0.001 to 0.05 part by weight, particularly preferably 0.002 to 0.03 part by weight. If the content is too small, the content effect may not be sufficiently obtained. Conversely, if the content is too large, it tends to be difficult to obtain a uniform film. In addition, when 2 or more types of salts are contained in modified | denatured EVOH (A), it is preferable that the total amount exists in the range of said content.

The method of containing acetic acid, acetate, and phosphate in the modified EVOH (A) is not particularly limited. For example, EVOH (a) obtained by the following methods i) to iv) and a lactone are grafted. And a method of treating the modified EVOH by the following methods v) to vi).
For example, EVOH (a) contains an additive such as acetic acid, acetate, phosphate, etc., i) contacting a porous precipitate of EVOH having a water content of 20 to 80% by weight with an aqueous solution of the additive And adding the additive to the porous EVOH and then drying; ii) adding the additive to a uniform solution of EVOH (water / alcohol solution, etc.), and then extruding it into a coagulation liquid in a strand; Next, the obtained strand is cut into pellets and further dried; iii) The EVOH and the additive are mixed together and then melt-kneaded with an extruder or the like; iv) At the time of producing the EVOH, The alkali (sodium hydroxide, potassium hydroxide, etc.) used in the saponification process is neutralized with organic acids such as acetic acid, and the amount of residual organic acids such as acetic acid and by-products is adjusted by washing with water. Benefit method and the like can be mentioned.
In order to obtain the effects of the present invention more remarkably, the method i) and ii), which are excellent in the dispersibility of the additive, and the method iv) are preferred when an organic acid and a salt thereof are contained.

For example, as a method of adding an additive such as acetic acid, acetate, and phosphate to the modified EVOH (A), v) the modified EVOH (A) is brought into contact with an aqueous solution of the additive, and the modified EVOH Examples thereof include a method of adding an additive to (A) and then drying; vi) a method of mixing the modified EVOH (A) and the additive in a lump and then melt-kneading with an extruder or the like.

  The modified EVOH resin (A) is usually marketed in the form of pellets and used for various melt moldings. The shape of the pellet includes, for example, a spherical shape, a cylindrical shape, a cubic shape, a rectangular parallelepiped shape, etc., and is usually a spherical shape (rugby ball shape) or a cylindrical shape, and its size is convenient when used as a molding material later. From the viewpoint of safety, in the case of a spherical shape, the diameter is usually 1 to 6 mm, preferably 2 to 5 mm, particularly preferably 2.5 to 4.5 mm, and the height is usually 1 to 6 mm, preferably 1.5 to 5 mm. The diameter of the bottom is usually 1 to 6 mm, preferably 2 to 5 mm, particularly preferably 2.5 to 4.5 mm, and the length is usually 1 ˜6 mm, preferably 2 to 5 mm, particularly preferably 2 to 3.5 mm.

<Description of boron compound (B)>
The boron compound (B) in the present invention means boric acid or a metal salt thereof.
Examples of borate metal salts include calcium borate, cobalt borate, zinc borate (zinc tetraborate, zinc metaborate, etc.), aluminum borate / potassium borate, ammonium borate (ammonium metaborate, ammonium tetraborate). , Ammonium pentaborate, ammonium octaborate, etc.), cadmium borate (cadmium orthoborate, cadmium tetraborate, etc.), potassium borate (potassium metaborate, potassium tetraborate, potassium pentaborate, potassium hexaborate) , Potassium octaborate, etc.), silver borate (silver metaborate, silver tetraborate, etc.), copper borate (cupric borate, copper metaborate, copper tetraborate, etc.), sodium borate (metaborate) Sodium, sodium diborate, sodium tetraborate, sodium pentaborate, sodium hexaborate, sodium octaborate ), Lead borate (lead metaborate, lead hexaborate, etc.), nickel borate (nickel orthoborate, nickel diborate, nickel tetraborate, nickel octaborate, etc.), barium borate (barium orthoborate, Barium metaborate, barium diborate, barium tetraborate, etc.), bismuth borate, magnesium borate (magnesium orthoborate, magnesium diborate, magnesium metaborate, trimagnesium tetraborate, pentamagnesium tetraborate, etc.) , Manganese borate (manganese borate, manganese metaborate, manganese tetraborate, etc.), lithium borate (lithium metaborate, lithium tetraborate, lithium pentaborate, etc.), borax, carnite , Borate minerals such as inyoite, agate stone, suian stone, and zyberite.
Such a boron compound (B) is preferably water-soluble from the viewpoint of handleability. Of these, borax, boric acid, sodium borate (sodium metaborate, sodium diborate, sodium tetraborate, sodium pentaborate, sodium hexaborate, sodium octaborate, etc.) are particularly preferred. Is boric acid.

  The compounding quantity of a boron compound (B) is 1-150 ppm normally in conversion of boron with respect to modified EVOH (A), Preferably it is 10-120 ppm, Most preferably, it is 30-100 ppm. If the compounding amount of the boron compound (B) is too large, the extrudability is lowered. On the other hand, if the compounding amount of the boron compound (B) is too small, the moldability is degraded.

<Method for adjusting resin composition>
The resin composition of the present invention contains the above-described modified EVOH (A) with a specific amount of boron compound (B).
As a method of containing the boron compound in the modified EVOH (A), for example, the modified EVOH (A) is brought into contact with an aqueous solution of the boron compound (B), and the boron compound (B) is contained in the modified EVOH (A). And a method of dry blending the modified EVOH (A) and the boron compound (B). Among these, from the viewpoint of easy adjustment, a method of dry blending the modified EVOH (A) with the boron compound (B) is preferable.

  Thus, although the resin composition of the present invention is obtained, the resin composition further includes, if necessary, a range that does not inhibit the effects of the present invention (for example, 5% by weight or less of the resin composition). Additives such as lubricants, plasticizers, heat stabilizers, UV absorbers, antioxidants, colorants, desiccants, oxygen absorbers, antibacterial agents, fillers, and other resins such as polyolefins and polyamides can also be blended It is. In particular, hydrotalcite compounds, hindered phenols, hindered amine heat stabilizers, and metal salts of higher aliphatic carboxylic acids can be added as gel generation inhibitors.

  It is also possible to blend two or more different modified EVOH resins (A), or blend a modified EVOH resin (A) with a normal EVOH resin.

<Use of resin composition>
The resin composition containing the modified EVOH (A) and boron compound (B) of the present invention thus obtained can be molded into, for example, a film, a sheet, a cup or a bottle by melt molding. As the melt molding method, for example, an extrusion molding method (T-die extrusion, inflation extrusion, blow molding, melt spinning, profile extrusion, etc.) and an injection molding method are mainly employed. The melt molding temperature is usually appropriately selected from the range of 150 to 300 ° C.

The molded product may be used for various purposes as it is, but usually it is laminated with another base material to further increase the strength or to give other functions.
As such another base material, a base material made of a thermoplastic resin is useful. Examples of the thermoplastic resin include linear low density polyethylene, low density polyethylene, ultra low density polyethylene, medium density polyethylene, polyethylene such as high density polyethylene, polypropylene, ethylene-propylene (block and random) copolymers, Polyolefins such as propylene-α-olefin (α-olefin having 4 to 20 carbon atoms) copolymer, polybutene, polypentene, and the like, grafted polyolefins obtained by graft-modifying these polyolefins with unsaturated carboxylic acid or esters thereof, ionomers, Ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, polyester resin, polyamide resin (including copolyamide), 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 them. . Among these, from the viewpoint of practicality such as physical properties (particularly strength) of the laminate, polyolefin resins and polyamide resins are preferable, and polyethylene and polypropylene are particularly preferably used.

  These base resins contain an antioxidant, an antistatic agent, a lubricant, a core material, an antiblocking agent, an ultraviolet absorber, a wax and the like as conventionally known within a range not impairing the gist of the present invention. May be.

The lamination method when laminating the resin composition of the present invention with another substrate can be carried out by a known method. For example, a method of melt extrusion laminating another base resin to a molded article such as a film or sheet comprising the resin composition of the present invention, and conversely a method of melt extrusion laminating the resin composition of the present invention to another base material, A method of co-extrusion of the resin composition of the present invention and other base resin, an organic titanium compound, an isocyanate compound, a polyester-based compound, a polyurethane compound, etc. And a method of dry lamination using a known adhesive, a method of applying a solution of the resin composition of the present invention on another substrate and then removing the solvent.
Among these, the co-extrusion method is preferable from the viewpoint of cost and environment.

  The layer structure of the laminate is a / b when the resin composition-containing layer of the present invention is a (a1, a2,...) And the thermoplastic resin-containing layer is b (b1, b2,...). B / a / b, a / b / a, a1 / a2 / b, a / b1 / b2, b2 / b1 / a / b1 / b2, b2 / b1 / a / b1 / Arbitrary combinations such as a / b1 / b2 are possible. Further, when R is a recycle layer containing a mixture of the resin composition and a thermoplastic resin, which is obtained by re-melt molding an end portion or a defective product generated in the process of manufacturing the laminate, 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.

  In the above layer structure, an adhesive resin layer can be provided between the respective layers as necessary, and a known one may be used as the adhesive resin. Such an adhesive resin varies depending on the type of resin b, and may be appropriately selected. Typically, however, an unsaturated carboxylic acid or its anhydride is chemically bonded to a polyolefin resin by an addition reaction or a graft reaction. And a modified olefin polymer containing a carboxyl group obtained in this manner. 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 A modified ethylene-vinyl acetate copolymer and the like, and one or a mixture of two or more selected from these are preferable. Further, these adhesive resins can be blended with the resin composition of the present invention, other rubber / elastomer components such as EVOH, polyisobutylene, and ethylene-propylene rubber, and further, the resin of the b layer. . In particular, blending a polyolefin resin different from the base polyolefin resin of the adhesive resin is useful because the adhesiveness may be improved.

  The laminated body as described above is then subjected to (heating) stretching treatment as necessary, and such (heating) stretching treatment is a film or sheet-like laminated body that is thermally uniformly heated. It means an operation for uniformly forming a tube or a film by chuck, plug, vacuum force, pneumatic force, blow or the like. The stretching may be either uniaxial stretching or biaxial stretching, and in the case of biaxial stretching, it may be simultaneous stretching or sequential stretching.

  Examples of the stretching method include a roll stretching method, a tenter stretching method, a tubular stretching method, a stretching blow method, and a vacuum / pressure forming method. Among these, a method having a high stretching ratio can be employed. In the case of biaxial stretching, both a simultaneous biaxial stretching method and a sequential biaxial stretching method 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 tends to decrease, and if it is too high, it tends to be difficult to maintain a stable stretched state.

In addition, you may heat-set next for the purpose of providing dimensional stability after extending | stretching. The heat setting can be carried out by a known means. For example, the stretched film is usually heat-treated at 80 to 180 ° C., preferably 100 to 165 ° C. for about 2 to 600 seconds while maintaining a tension state.
Further, when the multilayer stretched film obtained from the resin composition of the present invention is used as a shrink film, in order to impart heat shrinkability, for example, cold air is applied to the stretched film without performing the above heat setting. Perform processing such as applying and cooling.

  The thickness of the thermoplastic resin layer and adhesive resin layer of the laminate cannot be generally stated depending on the layer structure, type of thermoplastic resin, type of adhesive resin, application and packaging form, required physical properties, etc. The resin layer is usually selected from the range of about 10 to 1000 μm, preferably 50 to 500 μm, and the adhesive resin layer is about 5 to 500 μm, preferably about 10 to 250 μm.

  The thickness of the resin composition-containing layer of the present invention varies depending on the required gas barrier properties, but is usually 5 to 500 μm, preferably 10 to 250 μm, particularly preferably 20 to 100 μm, and the thickness is thin. If the thickness is too large, sufficient gas barrier properties tend not to be obtained. Conversely, if the thickness is too large, the flexibility of the film tends to decrease.

  It is also possible to extrude-coating another base material on the obtained laminate or laminating a film, sheet, or the like of another base material with an adhesive. In addition to the above-mentioned thermoplastic resin, any substrate (paper, metal foil, uniaxial or biaxially stretched plastic film or sheet and its inorganic compound deposit, woven fabric, non-woven fabric, metallic cotton, wood, etc.) can be used as the material. It can be used.

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

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the description of the examples unless it exceeds the gist.
In the examples, “part” means a weight basis.

<Example 1>

[Production of modified EVOH (A)]
EVOH (a1) 100 parts, ε-caprolactone 30 parts, tetra-n-butoxy, ethylene content 32 mol%, saponification degree of vinyl acetate part 99.6 mol%, MFR 12 g / 10 min (210 ° C., load 2160 g) 0.03 part of titanium was charged into a vertical stirring tank type manufacturing apparatus, and the temperature was raised from 25 ° C. to 200 ° C. at a heating rate of 0.5 ° C./min while stirring at a rotation speed of 50 rpm in a nitrogen stream. Then, modified EVOH (A1) grafted with aliphatic polyester by grafting and graft reaction at this temperature for 3 hours (ethylene content 32 mol%, saponification degree 99.6 mol%, MFR 13 g / 10 min (210 ° C., load 2160 g), EVOH (a1) unit content / aliphatic polyester unit content = 77% / 23%, modification rate: 7.2 mol%, average chain length: 1.3 mol, Point: 108 ° C.) was obtained.

[Production of resin composition]
Boric acid as the boron compound (B) was dry blended with the modified EVOH (A1) obtained above to obtain a resin composition of the present invention. The boron content was 70 ppm in terms of boron with respect to the modified EVOH (A1).
The following evaluation was performed about the obtained resin composition.

[Evaluation of extrusion moldability]
Ejected from the die when lowered at 210 ° C with a piston lowering speed of 3 mm / min using a capillograph (manufactured by Toyo Seiki Seisakusho) equipped with an orifice with an inner diameter of 1 mmφ and a length of 10 mm at the tip. The resulting strand was hooked on a pulley with a load cell and pulled at a constant speed, and the load at the point where the load applied to the pulley with the load cell was stabilized was defined as melt tension.
Using a melt tension at a take-up speed of 5 m / min and a take-up speed of 30 m / min, the ratio of the melt tension ((take-up speed 30 m / min) / (take-up speed 5 m / min)) was calculated as the increase rate of the melt tension.
In addition, it means that it is excellent in the extrusion moldability at the time of raising take-up speed, so that the increase rate of the melt tension calculated by the above formula is large.

<Comparative Example 1>
In Example 1, it carried out similarly except not having added the boron compound (B), and evaluated similarly to Example 1. FIG.

<Reference Example 1>
In Example 1, instead of modified EVOH (A1), an unmodified EVOH having an ethylene content of 32 mol%, a saponification degree of vinyl acetate moiety of 99.6 mol%, MFR of 12 g / 10 min (210 ° C, load of 2160 g) ( The same procedure as in Example 1 was performed except that A ′) was used.

<Reference Example 2>
Evaluation was performed in the same manner as in Example 1 except that the boron compound (B) was not added in Reference Example 1.

Table 1 shows the evaluation results of the extrusion moldability.
[Table 1]

  As can be seen from Table 1, when the boron compound (B) was added to the modified EVOH (A), the rate of increase in melt tension was larger than when the boron compound was simply added to the EVOH. It turns out that it is excellent in extrusion moldability.

  Since the resin composition containing the modified EVOH and the boron compound of the present invention is excellent in extrusion moldability, it is extremely useful industrially. For example, it is useful for containers and lids made of bags, cups, trays, tubes, bottles, etc. made of films, sheets, stretched films, etc., and these include seasonings such as mayonnaise, dressing, miso, etc. It is useful as various packaging material containers for fermented foods such as fats and oils, fat oils such as salad oil, beverages, cosmetics, and pharmaceuticals.

Claims (4)

  A resin composition comprising a modified ethylene-vinyl ester copolymer saponified product (A) and a boron compound (B) grafted with an aliphatic polyester, wherein the boron compound (B) content is modified ethylene-vinyl. Resin composition characterized by being 1 to 150 ppm in terms of boron based on saponified ester copolymer (A).   Modified ethylene-vinyl ester copolymer saponified product (A) grafted with aliphatic polyester is subjected to ring-opening / grafting reaction of ε-caprolactones in the presence of ethylene-vinyl ester copolymer saponified product (a) The resin composition according to claim 1, wherein the resin composition is obtained by:   The resin composition according to claim 1 or 2, wherein the modified ethylene-vinyl ester copolymer saponified product (A) grafted with the aliphatic polyester has a modification rate of 0.1 to 30 mol%.   The resin composition according to any one of claims 1 to 3, wherein the boron compound (B) is boric acid.