JP7127320B2 - Method for producing adhesive resin composition, method for forming adhesive layer, and method for producing laminate - Google Patents

Description

TECHNICAL FIELD The present invention relates to an adhesive resin composition and an adhesive layer and laminate using the same. More particularly, it relates to an adhesive resin composition containing a modified polyester-based elastomer and a propylene-based resin, an adhesive layer comprising this adhesive resin composition, and a laminate containing this adhesive layer.

Ethylene-vinyl alcohol copolymer (hereafter referred to as EVOH) has excellent gas barrier properties. Therefore, by applying a laminate containing an EVOH layer to a food packaging material, it is possible to extend the shelf life of food. , it is possible to reduce long-distance distribution and food waste. However, since EVOH has a hydroxyl group, which is a hydrophilic group, it is easily affected by humidity, and there is a problem that gas barrier properties deteriorate under high humidity conditions. As a method for improving this drawback, it is effective to laminate the EVOH layer with a layer made of a resin having low moisture permeability such as polyolefin or polystyrene (hereinafter referred to as PS).

Conventionally, it is known that polar group-grafted polyolefin is used as an adhesive resin for adhesion between EVOH and polyolefin. Adhesion is caused by chemical interaction between the group and the hydroxyl group of EVOH, while the polar group-grafted polyolefin and the polyolefin are presumed to be compatible with each other and exhibit adhesive strength.

On the other hand, for adhesion between PS and EVOH, adhesion methods different from adhesion between EVOH and polyolefin have been proposed. and an adhesive resin composition comprising a tackifier. Here, it is disclosed that a petroleum-based hydrocarbon resin, rosin, or the like is used as the tackifier.

JP-A-10-265751 JP-A-11-35749

The methods for bonding PS and EVOH described in Patent Documents 1 and 2 use tackifiers such as petroleum-based hydrocarbon resins and rosin, but both are poor in oil resistance. When a laminate in which a PS layer and an EVOH layer are adhered with an adhesive layer made of an adhesive resin composition containing such a tackifier is used for packaging oily foods, the tackifier dissolves into the oil from the adhesive layer. I had concerns. As a result, when a laminate in which a PS layer and an EVOH layer are adhered with such an adhesive layer is used as a food packaging material, the contents are restricted.
For this reason, it is required to improve the oil resistance of the adhesive resin composition in order to expand suitability for contents.

The present invention provides an adhesive resin composition having high adhesive strength to a PS layer and an EVOH layer and excellent oil resistance without using a tackifier, and an adhesive layer and laminate using this adhesive resin composition. The task is to provide

The present inventors have made intensive studies to solve the above problems, and have found that by using an adhesive resin composition containing a modified polyester-based elastomer having a specific structural unit and a specific propylene-based resin, the adhesive resin composition does not contain a tackifier. It has been found that it has excellent oil resistance and can bond a styrene-based resin layer and an ethylene-vinyl alcohol copolymer layer with high strength.

That is, the gist of the present invention is as follows.

[1] Obtained by modifying a saturated polyester thermoplastic elastomer having a polyalkylene ether glycol segment content of 58 to 73% by mass with an unsaturated carboxylic acid and/or a derivative thereof in the presence of a radical generator. A modified polyester-based elastomer (A) and a propylene-based resin (B) that satisfies the following conditions (Bi) and (B-ii), or (Bi) and (B-iii): The proportion of the modified polyester-based elastomer (A) is 25 to 65% by mass, and the proportion of the propylene-based resin (B) is 35 to 75% by mass, based on the total 100% by mass of the elastomer (A) and the propylene-based resin (B). An adhesive resin composition.
(Bi) The heat of fusion is in the range of 2 to 50 mJ/mg.
(B-ii) A propylene/α-olefin copolymer, wherein the α-olefin is ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-heptene, 1-hexene, 1 - at least two selected from the group consisting of octene and 1-nonene.
(B-iii) Propylene homopolymer.

[2] The adhesive resin composition according to [1], which does not contain a tackifier.

[3] The evaporation residue in the heptane elution test of the evaporation residue test method of the specifications and standards for foods, additives, etc. (Ministry of Health and Welfare Notification No. 370 of 1959) is 400 μg / ml or less, [1] or [2] The adhesive resin composition according to .

[4] An adhesive layer made of the adhesive resin composition according to any one of [1] to [3].

[5] A laminate comprising the adhesive layer according to [4].

[6] The laminate according to [5], wherein the layer in contact with one surface of the adhesive layer is a styrene-based resin layer, and the layer in contact with the other surface is an ethylene-vinyl alcohol copolymer layer.

ADVANTAGE OF THE INVENTION According to this invention, the adhesive resin composition which is excellent in oil resistance and can express high adhesive strength with respect to a PS layer and an EVOH layer is provided without using a tackifier. According to the adhesive resin composition of the present invention, it is possible to obtain a laminate suitable for use as a packaging material for oily foods without being restricted by the content even in food packaging applications.

The present invention will be described in detail below, but the following description is an example of an embodiment of the present invention, and the present invention is not limited to the following description content as long as it does not exceed the gist of the present invention. Arbitrary modifications can be made without departing from the gist of the invention.
In addition, in the present invention, when a numerical value or a physical property value is sandwiched before and after the "~", it is used to include the values before and after it.

[1] Adhesive resin composition The adhesive resin composition of the present invention comprises a saturated polyester thermoplastic elastomer having a polyalkylene ether glycol segment content of 58 to 73% by mass in the presence of a radical generator, 25 to 65% by mass of a modified polyester-based elastomer (A) obtained by modification treatment with a saturated carboxylic acid and/or a derivative thereof, and the following conditions (Bi) and (B-ii), or (Bi) and It is characterized by containing 100 mass % in total of 35 to 75 mass % of the propylene resin (B) that satisfies (B-iii).
(Bi) The heat of fusion is in the range of 2 to 50 mJ/mg.
(B-ii) A propylene/α-olefin copolymer, wherein the α-olefin is ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-heptene, 1-hexene, 1 - at least two selected from the group consisting of octene and 1-nonene.
(B-iii) Propylene homopolymer.

[1-1] Modified polyester elastomer (A)
Modification in the present invention includes graft modification of a saturated polyester thermoplastic elastomer containing a polyalkylene ether glycol segment with an unsaturated carboxylic acid and/or a derivative thereof, terminal modification and modification by transesterification, modification by decomposition reaction, and the like. Say. Specifically, the site where the unsaturated carboxylic acid and/or derivative thereof is bonded may be a terminal functional group or an alkyl chain portion, particularly a terminal carboxylic acid, a terminal hydroxyl group, or an ether bond of a polyalkylene ether glycol segment. Examples include carbon atoms at the α-position and β-position. In particular, it is presumed that many are bonded to carbon atoms at the α-position with respect to the ether bond of the polyalkylene ether glycol segment.

The saturated polyester thermoplastic elastomer, which is the raw material of the modified polyester elastomer (A), is usually a block copolymer composed of a soft segment containing a polyalkylene ether glycol segment and a hard segment containing an aromatic polyester. It is important that the soft segment is a polyalkylene ether glycol segment or a segment containing this for developing adhesiveness. Unsaturated polyester elastomers containing double or triple bonds between carbon atoms are prone to coloration due to heat and light, and are prone to gel during molding. In the present invention, a saturated polyester-based thermoplastic elastomer is used because it is not suitable for a composite laminate having a shape due to problems with its appearance.

The content of the polyalkylene ether glycol segment in the saturated polyester thermoplastic elastomer, which is the raw material of the modified polyester elastomer (A), must be 58 to 73% by mass in the saturated polyester elastomer, preferably 60 to 70% by mass. If the content of the polyalkylene ether glycol segment is less than the above range, it is difficult to exhibit sufficient adhesion to the styrene-based resin layer, and if the content exceeds the above range, the material strength will decrease, resulting in insufficient adhesion. difficult to obtain.

Examples of polyalkylene ether glycols constituting this soft segment include polyethylene glycol, poly(1,2 and 1,3-propylene ether) glycol, poly(tetramethylene ether) glycol, poly(hexamethylene ether) glycol, and the like. mentioned. Especially preferred is poly(tetramethylene ether) glycol.

In the present invention, polyalkylene ether glycol having a number average molecular weight of 400 to 6,000 is usually used, preferably 600 to 4,000, particularly preferably 1,000 to 3,000. When the number average molecular weight is 400 or more, the unsaturated carboxylic acid and/or its derivative can provide a sufficient modification effect, and good adhesiveness can be exhibited. On the other hand, when it is 6000 or less, phase separation in the system is difficult to occur, and deterioration of physical properties of the polymer obtained by copolymerization or the like can be suppressed. The term "number average molecular weight" as used herein is measured by gel permeation chromatography (GPC). A POLYTETRAHYDROFURAN calibration kit from POLYMER LABORATORIES, UK may be used for GPC calibration.

Saturated polyester thermoplastic elastomers are usually
i) aliphatic and/or cycloaliphatic diols having 2 to 12 carbon atoms,
ii) an aromatic dicarboxylic acid and/or an alicyclic dicarboxylic acid or an alkyl ester thereof;
iii) A polyalkylene ether glycol having a number average molecular weight of 400 to 6000 is used as a raw material, and it can be obtained by polycondensing an oligomer obtained by an esterification reaction or a transesterification reaction.

As the aliphatic and/or alicyclic diol having 2 to 12 carbon atoms, those commonly used as raw materials for polyesters, particularly polyester thermoplastic elastomers, can be used. Examples thereof include ethylene glycol, propylene glycol, trimethylene glycol, 1,4-butanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, etc. Among them, 1,4-butanediol and ethylene glycol are Preferred is 1,4-butanediol. These diols can be used singly or as a mixture of two or more.

As the aromatic dicarboxylic acid and/or alicyclic dicarboxylic acid, those commonly used as raw materials for polyesters, particularly polyester thermoplastic elastomers, can be used. Examples include terephthalic acid, isophthalic acid, phthalic acid, 2, 6-naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid and the like. Among these, terephthalic acid and 2,6-naphthalenedicarboxylic acid are preferred, and terephthalic acid is particularly preferred. Two or more of these dicarboxylic acids may be used in combination.
When using alkyl esters of aromatic dicarboxylic acids and/or alicyclic dicarboxylic acids, dimethyl esters and diethyl esters of the above dicarboxylic acids are used. Preferred are dimethylterephthalate and 2,6-dimethylnaphthalate.

In addition to the above components, trifunctional triols, tricarboxylic acids, or esters thereof may be copolymerized in small amounts, and aliphatic dicarboxylic acids such as adipic acid and their dialkyl esters may also be used as copolymer components. good too.

As the type and suitable molecular weight range of the polyalkyl ether glycol, the same ones as described above can be used.

Commercially available products can also be used as the saturated polyester thermoplastic elastomer composed of the polyester-polyether block copolymer suitable for the present invention.・"Hytrel" manufactured by DuPont can be used.

Examples of unsaturated carboxylic acids and/or derivatives thereof used for modifying saturated polyester thermoplastic elastomers include acrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, and isocrotonic acid. unsaturated carboxylic acids; for example, 2-octen-1-yl succinate, 2-dodecen-1-yl succinate, 2-octadecen-1-yl succinate, maleic anhydride, 2, 3-dimethylmaleic anhydride, bromomaleic anhydride, dichloromaleic anhydride, citraconic anhydride, itaconic anhydride, 1-butene-3,4-dicarboxylic anhydride, 1-cyclopentene-1,2 -dicarboxylic anhydride, 1,2,3,6-tetrahydrophthalic anhydride, 3,4,5,6-tetrahydrophthalic anhydride, exo-3,6-epoxy-1,2,3,6- Tetrahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, methyl-5-norbornene-2,3-dicarboxylic anhydride, endo-bicyclo[2.2.2]oct-5-ene- 2,3-dicarboxylic anhydride, bicyclo [2.2.2. ] Unsaturated carboxylic anhydrides such as oct-7-ene-2,3,5,6-tetracarboxylic anhydride; methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, Butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, glycidyl methacrylate, dimethyl maleate , maleic acid (2-ethylhexyl), unsaturated carboxylic acid esters such as 2-hydroxyethyl methacrylate, and the like. Among these, unsaturated carboxylic acid anhydrides are preferred.

The unsaturated carboxylic acid and/or derivative thereof may be appropriately selected according to the saturated polyester thermoplastic elastomer to be modified and the modification conditions, and two or more of them may be used in combination. The unsaturated carboxylic acid and/or its derivative can be dissolved in an organic solvent or the like and added.

Examples of radical generators used for radical reaction during modification treatment include t-butyl hydroperoxide, cumene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 2,5-dimethyl- 2,5-bis(tert-butyloxy)hexane, 3,5,5-trimethylhexanoyl peroxide, t-butyl peroxybenzoate, benzoyl peroxide, dicumyl peroxide, 1,3-bis(t-butyl Peroxyisopropyl)benzene, dibutyl peroxide, methyl ethyl ketone peroxide, potassium peroxide, organic and inorganic peroxides such as hydrogen peroxide, 2,2-azobisisobutyronitrile, 2,2'-azobis(isobutylamide ) dihalides, 2,2′-azobis[2-methyl-N-(2-hydroxyethyl)propionamide], azo compounds such as azodi-t-butane, and carbon radical generators such as dicumyl.

These radical generators may be appropriately selected according to the type of saturated polyester thermoplastic elastomer used in the modification treatment, the type of unsaturated carboxylic acid and/or its derivative, and the modification conditions. You can The radical generator can also be added by dissolving it in an organic solvent or the like.

Further, in order to further improve the adhesiveness of the obtained adhesive resin composition, a compound having an unsaturated bond can be used together as a modification aid in addition to the radical generator during the modification treatment.
A compound having an unsaturated bond refers to a compound having a carbon-carbon multiple bond other than an unsaturated carboxylic acid and/or a derivative thereof. Specifically, styrene, methylstyrene, ethylstyrene, isopropylstyrene, phenyl Examples thereof include vinyl aromatic monomers such as styrene and o-chloromethylstyrene. An improvement in modification efficiency can be expected by these formulations.

The blending ratio of the unsaturated carboxylic acid and/or its derivative and the radical generator used in the modification treatment is 0.01 to 30 parts by mass of the unsaturated carboxylic acid and/or its derivative per 100 parts by mass of the saturated polyester elastomer. , preferably 0.05 to 5 parts by mass, more preferably 0.1 to 2 parts by mass, particularly preferably 0.1 to 1 part by mass, and the radical generator is 0.001 to 3 parts by mass, preferably 0 0.005 to 0.5 parts by mass, more preferably 0.01 to 0.2 parts by mass, and particularly preferably 0.01 to 0.15 parts by mass.

When the blending amount of the unsaturated carboxylic acid and/or derivative thereof is at least the above lower limit, modification with the unsaturated carboxylic acid and/or derivative thereof can be sufficiently performed to develop good adhesiveness. Further, when the content is equal to or less than the above upper limit, it is possible to prevent the unsaturated carboxylic acid and/or its derivative itself from bonding to form lumps, resulting in poor appearance and poor adhesion.

Moreover, when the blending amount of the radical generator is at least the above lower limit, the modification with the unsaturated carboxylic acid and/or its derivative can be sufficiently performed, and good adhesiveness can be exhibited. Further, if it is equal to or less than the above upper limit, it is possible to suppress a decrease in the viscosity of the modified polyester elastomer (A) to be produced when it melts, and to apply sufficient shear when blending with the propylene resin (B). It becomes possible to enhance the dispersibility of the polyester elastomer (A) and develop good adhesiveness.

In the present invention, using compounding ingredients such as a saturated polyester thermoplastic elastomer, an unsaturated carboxylic acid and/or a derivative thereof, a radical generator, and a compound having an unsaturated bond, which is an optional ingredient, The blending method for obtaining the modified polyester-based elastomer (A) to be used includes a melt method, a solution method, a suspension dispersion method, and the like, and is not particularly limited. Practically, the melt-kneading method is preferred.

Specific methods for melt-kneading include powdery or granular saturated polyester thermoplastic elastomer, unsaturated carboxylic acid and/or its derivatives, radical generator, and optionally added components. A compound having an unsaturated bond is uniformly mixed at a predetermined mixing ratio using a Henschel mixer, a ribbon blender, a V-type blender, etc., and then a Banbury mixer, a kneader, a roll, a multi-screw kneading extrusion such as a single screw or a double screw. A method of kneading using a usual kneader such as a kneader can be exemplified.

The melt-kneading temperature of each component is usually in the range of 100 to 300°C, preferably in the range of 120 to 280°C, particularly preferably in the range of 150 to 250°C. Furthermore, the kneading order and method of each component are not particularly limited, and the saturated polyester thermoplastic elastomer, unsaturated carboxylic acid and/or its derivative, radical generator, and components added as necessary. A method of kneading a compound having a certain unsaturated bond at once, or a method of kneading a part of each component and then kneading the remaining component may be used. However, it is preferable to add the radical generator at the same time as the unsaturated carboxylic acid and/or its derivative or the compound having an unsaturated bond from the viewpoint of improving the adhesiveness of the resulting modified polyester elastomer (A).

The amount of modification of the modified polyester elastomer (A) produced in this way, as analyzed by infrared absorption spectroscopy, is desirably 0.01 to 15, more preferably 0.01 to 15, as expressed by the following formula. 03 to 2.5, more preferably 0.1 to 2.0, particularly preferably 0.1 to 1.8.
A ₁₇₈₆ / (Ast x r)
[However, A ₁₇₈₆ is the peak intensity at 1786 cm ^-1 measured on a modified polyester elastomer (A) film with a thickness of 20 μm, and Ast is the standard sample (the content of the polyalkylene ether glycol segment is 65 is the peak intensity of the reference wavenumber measured on a 20 μm-thick film of saturated polyester-based thermoplastic elastomer (% by mass), r is the mole fraction of the polyester segment in the modified polyester-based elastomer (A), It is a value divided by the mole fraction of the polyester segment in the standard sample. ]

A specific method for determining the value of the modified amount of the modified polyester elastomer (A) by infrared absorption spectroscopy is as follows.
That is, a film-like sample with a thickness of 20 μm is dried under reduced pressure at 100° C. for 15 hours to remove unreacted substances, and the infrared absorption spectrum is measured. From the obtained spectrum, the absorption peak due to the stretching vibration of the carbonyl group derived from the acid anhydride appearing at 1786 cm ^-1 (in the range of 1750 to 1820 cm ^-1 The tangent line connecting the foot of both sides of the absorption band is taken as the baseline. ) is calculated and defined as “peak intensity A ₁₇₈₆ ”.
On the other hand, the infrared absorption spectrum of a 20 μm thick film of a standard sample (saturated polyester thermoplastic elastomer having a polyalkylene ether glycol segment content of 65% by mass) is similarly measured. From the obtained spectrum, the reference wavenumber peak, for example, in the case of the aromatic polyester thermoplastic elastomer containing benzene rings, the absorption peak due to the out ^- of-plane deformation angle of C—H of the benzene rings appearing at 872 cm (850 to 900 cm A tangent line connecting the flanks on both sides of the absorption band in the range of ^-1 is used as a baseline) is calculated and defined as "peak intensity Ast". The reference wavenumber peak may be selected from those that are not affected by denaturation and do not have absorption peaks that overlap in the vicinity thereof.
From these peak intensities, the amount of modification is calculated by infrared absorption spectroscopy according to the above formula. At this time, as r, a value obtained by dividing the mole fraction of the polyester segment in the modified polyester elastomer (A) for which the amount of modification is to be obtained by the mole fraction of the polyester segment in the standard sample is used. Further, the mole fraction mr of the polyester segment in each sample is determined by the weight fractions (W ₁ and W ₂ ) of the polyester segment and the polyalkylene ether glycol segment and the molecular weights (e ₁ and e ₂ ), it is obtained by the following formula.
mr=(W1 _/ e1) _/ [(W1 _/ e1) _{+ (} W2 _/ e2)]

The melt flow rate (MFR, 230° C., 2.16 kg, JIS K7210) of the modified polyester elastomer (A) used in the present invention is preferably 1 to 60 g/10 min, more preferably 4 to 50 g/10 min. 10 minutes, more preferably 6 to 40 g/10 minutes. The MFR of the modified polyester-based elastomer (A) is preferably higher than the MFR of the propylene-based resin (B). The modified polyester-based elastomer (A) responsible for adhesiveness becomes a sea phase, and needs to come into contact with adherends such as PS and EVOH to exhibit adhesive strength. It is generally known that in an incompatible multi-component resin composition, a high MFR component forms a sea phase and a low MFR component forms an island phase. When the MFR of the modified polyester-based elastomer (A) is lower than that of the propylene-based resin (B), the modified polyester-based elastomer (A) forms an island phase and does not come into contact with the adherend, thus exhibiting no adhesive strength. If the MFR of the modified polyester-based elastomer (A) exceeds the above upper limit, the MFR difference from the propylene-based resin (B) is too large, a uniform dispersion structure cannot be obtained, and adhesion is not exhibited. If the MFR of the modified polyester-based elastomer (A) is less than the above lower limit, island phases are formed and adhesiveness is not exhibited.

The adhesive resin composition of the present invention may contain only one of the above modified polyester elastomers (A), and the saturated polyester thermoplastic elastomer used for modification, the unsaturated carboxylic acid and/or It may contain two or more derivatives having different types, physical properties, and the like.

[1-2] Propylene resin (B)
The propylene-based resin (B) used in the present invention must satisfy the following conditions (Bi) and (B-ii), or (Bi) and (B-iii).
(Bi) The heat of fusion is in the range of 2 to 50 mJ/mg.
(B-ii) a propylene/α-olefin copolymer, wherein the α-olefin as a comonomer of propylene is ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-heptene, At least two selected from the group consisting of 1-hexene, 1-octene and 1-nonene.
(B-iii) Propylene homopolymer.

When the heat of fusion exceeds 50 mJ/mg, the affinity with the modified polyester-based elastomer (A) is poor, and the mechanical strength as an adhesive resin composition is lowered. That is, even if the adhesive strength with the styrene-based resin layer or the ethylene-vinyl alcohol copolymer layer is good, the strength of the adhesive layer itself is low, so cohesive failure of the adhesive layer occurs, and good adhesive strength cannot be obtained. do not have.
A propylene-based resin containing only one comonomer has poor affinity with the modified polyester-based elastomer (A), and the mechanical strength as an adhesive resin composition decreases. Two or more kinds of comonomers are required to ensure sufficient affinity with the modified polyester-based elastomer (A).
In the case of a propylene homopolymer, the heat of fusion can be changed by controlling the stereoregularity. Affinity with the modified polyester-based elastomer (A) can be obtained by having low stereoregularity.

As described above, the propylene-based resin (B) must have a heat of fusion of 50 mJ/mg or less in order to maintain affinity with the modified polyester-based elastomer (A). , the amorphous component is insufficient and sufficient affinity with the modified polyester elastomer (A) cannot be obtained. The heat of fusion of the propylene-based resin (B) is preferably 45 mJ/mg or less, more preferably 40 mJ/mg or less. On the other hand, the lower limit of the heat of fusion is 2 mJ/mg or more, preferably 5 mJ/mg or more, from the viewpoint of maintaining mechanical strength.
The heat of fusion of the propylene-based resin (B) is measured by the method described in Examples below.

Further, the propylene-based resin (B) is a propylene/α-olefin copolymer, and the α-olefin is ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-heptene, At least two selected from the group consisting of 1-hexene, 1-octene and 1-nonene are required. In other words, it is a copolymer containing propylene as a main structural unit and two or more different α-olefins other than propylene as structural units. Among the types of α-olefins described above, it is preferred to include ethylene and 1-butene as copolymerization units.
When the propylene-based resin (B) is a propylene homopolymer, it is preferable that the stereoregularity is controlled and the stereoregularity is low.

Further, the melt flow rate (MFR, 230° C., 2.16 kg, JIS K7210) of the propylene resin (B) used in the present invention is preferably 0.1 to 20 g/10 min, more preferably 0.5. ~15 g/10 min, more preferably 0.5 to 10 g/10 min. When the MFR is at least the above lower limit, the difference in MFR from the modified polyester elastomer (A) is not too large, and sufficient dispersibility can be obtained by kneading, and as a result, good adhesiveness can be obtained. Moreover, when the MFR is equal to or less than the above upper limit, sufficient moldability can be imparted to the modified polyester-based elastomer (A) having insufficient moldability. In order to impart sufficient adhesion and moldability, the MFR of the propylene resin (B) is preferably smaller than the MFR of the modified polyester elastomer (A).

The adhesive resin composition of the present invention may contain only one of the propylene-based resins (B) described above, or may contain two or more different monomer compositions and other physical properties. good.

[1-3] Blending ratio The blending ratio of the modified polyester elastomer (A) and the propylene resin (B), which constitute the adhesive resin composition of the present invention, is 100% by mass in total of the modified polyester elastomer. (A) must be 25 to 65% by mass, preferably 30 to 60% by mass, more preferably 35 to 55% by mass. If the modified polyester-based elastomer (A) is less than the above range, the adhesive strength is poor, and if it exceeds the above range, the fluidity is too high, making it difficult to obtain a uniform film thickness during coextrusion molding, and the resin tends to absorb moisture. Foaming occurs at times, making it difficult to obtain a laminate of good quality, resulting in poor moldability.

On the other hand, the propylene-based resin (B) must be present in an amount of 35 to 75% by mass, preferably 40 to 75% by mass, based on the total 100% by mass of the modified polyester-based elastomer (A) and the propylene-based resin (B). 70% by mass, more preferably 45 to 65% by mass. If the content of the propylene-based resin (B) is less than the above range, problems with the moldability of the modified polyester elastomer (A) will occur.

In the adhesive resin composition of the present invention, the blending ratio of the propylene resin (B) is preferably higher than that of the modified polyester elastomer (A). That is, in order to obtain moldability as an adhesive resin composition, it is preferable to use the propylene-based resin (B) as a main component. On the other hand, as described above, a specific blending ratio of the modified polyester-based elastomer (A) is required to exhibit good adhesiveness.

[1-4] Other Additional Components In addition to the modified polyester elastomer (A) and the propylene-based resin (B), the adhesive resin composition of the present invention may contain other components as long as the objects and effects of the present invention are not impaired. Any component can be blended according to the requirements. Specifically, resin components other than the modified polyester-based elastomer (A) and the propylene-based resin (B), rubber components, talc, calcium carbonate, mica, fillers such as glass fibers, plasticizers such as paraffin oil, and antioxidants. agent, heat stabilizer, light stabilizer, ultraviolet absorber, neutralizer, lubricant, anti-fog agent, anti-blocking agent, slip agent, cross-linking agent, cross-linking aid, colorant, flame retardant, dispersant, antistatic agent , an antibacterial agent, a fluorescent whitening agent, and the like can be added. Among them, it is preferable to add at least one of various antioxidants such as phenol, phosphite, thioether, and aromatic amine antioxidants.

However, since the tackifier impairs oil resistance as described above, it is preferable that the adhesive resin composition of the present invention does not contain a tackifier. That is, the adhesive resin composition of the present invention contains a specific modified polyester-based elastomer (A) and a propylene-based resin (B), so that it can be used as an adhesive resin composition without blending a tackifier. The required properties can be fully satisfied.

[1-5] Production method The adhesive resin composition of the present invention is prepared by preparing the modified polyester elastomer (A), the propylene resin (B), and optionally other additional components by various known methods. , For example, by mixing using a tumbler blender, V blender, ribbon blender, Henschel mixer, etc., and after mixing, melt-kneading with a single screw extruder, twin screw extruder, Banbury mixer, kneader, etc., and granulating or pulverizing can be manufactured.

[1-6] Evaporation residue in heptane elution test The adhesive resin composition of the present invention is subjected to the heptane elution test of the evaporation residue test method of the specifications and standards for foods, additives, etc. (Ministry of Health and Welfare Notification No. 370 of 1959). is preferably 400 μg/ml or less.
The evaporation residue in the heptane elution test is an index of oil resistance, and if the evaporation residue in the heptane elution test is 400 μg/ml or less, the oil resistance is excellent and can be used for packaging a wide variety of contents.
A specific method for the heptane dissolution test is as described in Examples below.

[2] Adhesive Layer and Laminate The adhesive resin composition of the present invention is useful as an adhesive resin composition constituting an adhesive layer of a laminate. Thermoplastic resins such as styrene-based resins, EVOH, polyamide-based resins, polyolefin-based resins, polyester-based resins, acrylic-based resins, and polycarbonate resins are used as the layer in contact with the substrate. Specifically, EVOH having an ethylene content of 15 to 60 mol%; polyester resins (PES resins) such as polyethylene terephthalate (PET), copolymerized PET, polybutylene terephthalate, polyethylene naphthalate, and polycyclohexylene terephthalate; Polyamide-based resins (PA-based resins) such as 6-nylon, 6,6-nylon, 6-6,6-nylon, 12-nylon, xylylene group-containing polyamide resins (PA-based resins); polypropylene-based resins, polyethylene-based resins, ethylene/vinyl acetate Polyolefin resins (PO resins) such as copolymers, ethylene/acrylic acid copolymers, ethylene/acrylic acid ester copolymers, 4-methyl-1-pentene resins; general-purpose polystyrene, impact-resistant polystyrene, styrene - Styrene-based resins (PS-based resins) such as methacrylic acid copolymers; acrylic-based resins such as polyacrylonitrile, polymethyl methacrylate, acrylonitrile-methyl acrylate-butadiene copolymers; and polycarbonate resins (PC-based resins); A material such as a mixture of the resin and a filler such as a plate-like filler can be used.

Since the adhesive resin composition of the present invention is particularly excellent in adhesiveness between the EVOH layer and the styrene resin layer, at least a part thereof has a three-layer structure of EVOH layer/adhesive layer/styrene resin layer. The adhesive resin composition of the present invention is particularly effective as an adhesive layer forming material for a body.

The EVOH used for the layer in contact with the adhesive layer preferably has an ethylene content of 15 to 65 mol %, more preferably 25 to 50 mol %. If the ethylene content is too low, it is likely to be thermally decomposed, difficult to be melt-molded, and likely to absorb water and swell, resulting in poor water resistance. On the other hand, if the ethylene content is too high, gas permeability resistance tends to decrease.

The styrene-based resin used for the layer in contact with the adhesive layer is a styrene-based resin such as a homopolymer of styrene, a copolymer of styrene and acrylonitrile, methyl (meth)acrylate, etc., or a modified rubber product thereof. Specifically, thermoplastic resins called polystyrene, impact-resistant polystyrene (rubber-blended polystyrene), AS resin (SAN), ABS, SMA (styrene/maleic anhydride polymer), and the like are used.

The thickness of the adhesive layer made of the adhesive resin composition of the present invention is not particularly limited, but it is preferably in the range of 5 to 100 μm from the viewpoint of suppressing the thickness while obtaining sufficient adhesive strength.

[3] Method for producing laminate As a method for producing the laminate of the present invention, various conventionally known techniques can be employed. For example, by supplying individual molten resins melted in an extruder to a multilayer die and laminating them in the die, inflation films, T-die films, sheets, pipes, and individual melted resins Examples include co-injection molding, in which injection is performed with a time lag in the mold.

EXAMPLES The present invention will be described in more detail below using examples, but the present invention is not limited by the examples as long as the gist thereof is not exceeded.

[Modified polyester elastomer (A)]
<Constituent material of modified polyester elastomer (A)>
Saturated polyester thermoplastic elastomer A-1:
A polyester polyether block copolymer having polybutylene terephthalate as a hard segment and polytetramethylene ether glycol having a number average molecular weight of 2000 as a soft segment, wherein the content of the polytetramethylene ether glycol segment in the copolymer is 72% by mass saturated polyester thermoplastic elastomer unsaturated carboxylic acid B-1: Wako Pure Chemical Industries, Ltd. “Maleic anhydride (reagent special grade)”
Radical generator C-1: NOF Corporation "Nyper BW" (benzoyl peroxide)

<Production of Modified Polyester Elastomer (A)>
Saturated polyester thermoplastic elastomer A-1: 100 parts by mass, unsaturated carboxylic acid B-1: 0.5 parts by mass, radical generator C-1: 0.13 parts by mass, TEX- After melt-kneading in a 30-type kneader (diameter: 30 mm, temperature: 190-220° C.), the mixture was pelletized through a pelletizer to obtain a modified polyester elastomer (A).
The modified polyester elastomer (A) was evaluated for physical properties by the following methods.

(1) Melt flow rate (MFR)
The MFR of the obtained pellets was measured according to JIS K7210 under conditions of a temperature of 230° C. and a load of 2.16 kg.

(2) Modification amount by infrared absorption spectroscopy Using a sample formed into a film with a thickness of 20 μm by press molding (230 ° C.), an FT-IR device (JASCO FT / IR610, Jasco (manufactured by Co., Ltd.), the amount of modification was calculated by infrared absorption spectroscopy according to the procedure described in the text. The molar fraction of the polyester segment in the standard sample was 0.15, and Ast was 0.144.

The evaluation results of the modified polyester elastomer (A) are as follows.
MFR (230° C., 2.16 kg): 34 g/10 min Denaturation amount: 0.28

[Propylene resin (B)]
The following were used as the propylene-based resin (B).
B-1: Propylene/α-olefin copolymer (manufactured by Mitsui Chemicals, product name “Tafmer PN2060”)
α-Olefins other than propylene: Ethylene and 1-butene MFR (230°C, 2.16 kg): 6 g/10 minutes Heat of fusion: 15 mJ/mg
B-2: Propylene/α-olefin copolymer (manufactured by Exxon Mobil Chemical Company, product name “VISTAMAXX3000”)
α-Olefins other than propylene: Ethylene MFR (230°C, 2.16 kg): 8 g/10 minutes Heat of fusion: 25 mJ/mg
B-3: Propylene/α-olefin copolymer (manufactured by Mitsui Chemicals, product name “Tafmer XM7070”)
α-Olefins other than propylene: 1-butene MFR (230°C, 2.16 kg): 7 g/10 minutes Heat of fusion: 40 mJ/mg
B-4: Propylene/α-olefin copolymer (manufactured by Japan Polypropylene Corporation, product name “WINTEC WFX4M”)
α-Olefins other than propylene: Ethylene MFR (23°C, 2.16 kg): 7 g/10 minutes Heat of fusion: 85 mJ/mg
B-5: Propylene homopolymer (manufactured by Japan Polypropylene Corporation, product name "Novatec PP MA3")
α-Olefins other than propylene: not contained MFR (230°C, 2.16 kg): 10 g/10 minutes Heat of fusion: 100 mJ/mg

The physical properties of the propylene-based resin (B) were evaluated by the methods described below.

(1) Melt flow rate (MFR)
The MFR was measured under conditions of a temperature of 230° C. and a load of 2.16 kg according to JIS K7210.

(2) Heat of fusion Using a differential scanning calorimeter (DSC), once the temperature is raised to 200 ° C. to erase the heat history, the temperature is lowered to -10 ° C. at a temperature drop rate of 10 ° C./min, and the temperature is raised again. The temperature at the top of the endothermic peak measured at a rate of 10°C/min was taken as the melting peak temperature, and the integrated value of the endothermic peak from 20°C to 180°C was taken as the heat of fusion. The unit is mJ/mg.

[Example 1]
45% by mass of modified polyester-based elastomer (A) and 55% by mass of propylene-based resin (B-1) were blended, and after tumble blending, a twin-screw extruder (temperature: 200°C, discharge rate: 10 kg/hour, rotation speed: 300 rpm) was used. ), extruded from a die into strands, and cut to prepare an adhesive resin composition, which was then subjected to the following adhesive evaluation and oil resistance evaluation.
Table 1 shows the results.

[Adhesion evaluation]
Using the obtained adhesive resin composition, a T-die molding machine was used to laminate 4 kinds of 5 layers of impact-resistant polystyrene/adhesive resin composition/EVOH/adhesive resin composition/linear low-density polyethylene. A film was cast. A film having a total thickness of 100 μm was obtained at a molding temperature of 230° C. and a line speed of 20 m/min with a layer structure of 30/10/20/10/30 μm in thickness. PS Japan's "HT478" for the impact-resistant polystyrene layer, Kuraray's "EVAL F101B" (ethylene content: 32 mol%) for the EVOH layer, and Japan Polyethylene Co., Ltd. for the linear low-density polyethylene layer. "Novatec C6 SF8402" was used.
The resulting laminated film was cut into strips with a width of 15 mm, and adhesion between one impact-resistant polystyrene layer and four layers of adhesive resin composition/EVOH/adhesive resin composition/linear low-density polyethylene was performed. Strength was measured by a T-peel test at a peel speed of 300 mm/min. A peel strength of 3 N/15 mm or more is sufficient adhesive strength and can be used as a packaging material.

[Oil resistance evaluation: heptane elution test]
With reference to the heptane elution test of the evaporation residue test method of the standards for foods, additives, etc. (Notification No. 370 of the Ministry of Health and Welfare in 1959), the test was carried out as follows.
The adhesive resin composition was press-molded (at a temperature of 200° C., a pressure of 50 kgf/cm ² for 2 minutes) to prepare a sheet with a thickness of 0.5 mm. The sheet was placed in a flask with heptane and soaked at 25° C. for 1 hour to leach out the soluble matter. Thereafter, 250 ml of the test solution was transferred to an eggplant-shaped flask and concentrated under reduced pressure to a few ml. The concentrated solution and the flask were washed twice with about 5 ml of heptane each, placed in a heat-resistant glass evaporating dish with a known weight and dried at 105° C., and evaporated to dryness on a water bath. Then, after drying at 105° C. for 2 hours, it was allowed to cool in a desiccator. After that, it was weighed, the difference in weight between the front and back of the evaporating dish was determined, and the amount of evaporation residue was determined by the following equation.
Evaporation residue (μg/ml) = (ab) x 1000/collected amount of test solution (ml)
In the above formula, a is the weight difference (mg) before and after the evaporating dish, and b is the blank value (mg) obtained for the same amount of heptane as the test solution.
If the evaporation residue in the heptane elution test is 200 μg/ml or less, the oil resistance is excellent, and the content suitability as a packaging material can be broadened.
Note that the evaluation of oil resistance was performed only for those exhibiting a high adhesive strength of 3 N/15 mm or more.

[Examples 2 and 3 and Comparative Examples 1 to 4 and 7]
An adhesive resin composition was prepared in the same manner as in Example 1 except that the formulation was changed as shown in Table 1, and the adhesiveness and oil resistance were evaluated.
In Comparative Examples 1 to 7, the adhesive strength was 3 N/15 mm or less, which was insufficient, so the oil resistance test was not performed.
Table 1 shows the results.

[Comparative Example 5]
An attempt was made to evaluate the adhesiveness of the modified polyester elastomer (A) alone, but a laminated film could not be formed.

[Comparative Example 6]
Adhesion was evaluated for the propylene-based resin (B-1) alone. Table 1 shows the results.

[Comparative Example 8]
Prior art tackifier formulations were prepared as follows and subjected to adhesion evaluation and oil resistance evaluation, the results of which are shown in Table 1.
Linear ethylene/1-butene copolymer (density 0.920 g/cm ³ , MFR 2 g/10 min (190°C, 2.16 kg)) 100 parts by mass, maleic anhydride 1 part by mass, t-butyl per After mixing 0.04 parts by mass of oxybenzoate (Perbutyl D manufactured by NOF Corporation) for 1 minute with a super mixer, a twin-screw extruder (diameter 30 mm, L / D 42) was used to knead at a temperature of 230 ° C. and screw rotation. The mixture was melt-kneaded at several 300 rpm and a discharge rate of 15 kg/hour, extruded from a die into strands, and cut to obtain a modified ethylene polymer.
20 parts by mass of this ethylene-based polymer, 60 parts by mass of a linear ethylene/octene copolymer (density: 0.870 g/cm ³ , MFR: 1 g/10 min (190°C, 2.16 kg)), Arakawa Chemical as a tackifier After mixing 20 parts by mass of "Arcon P-115" manufactured by Kogyo Co., Ltd. for 1 minute with a super mixer, using a twin-screw extruder (diameter 30 mm, L / D 42), kneading temperature 230 ° C., screw rotation speed 300 rpm, discharge The mixture was melt-kneaded at a rate of 15 kg/hour, extruded from a die into a strand, and cut to obtain a conventional tackifier formulation.

As is clear from Table 1, the adhesive resin compositions of Examples 1 to 3 containing the modified polyester-based elastomer (A) and the propylene-based resin (B) within the specified range of the present invention, It exhibits a sufficient adhesive strength of 3.8 N/15 mm or more, has a small amount of evaporation residue in the heptane elution test, and has good oil resistance. In this way, since the adhesiveness and the oil resistance are exhibited in a well-balanced manner, it is possible to widen the suitability of the content as a packaging material.

Comparative Examples 1 and 2 are blended with a propylene-based resin (B-2) or (B-3) containing only one type of α-olefin, which is a copolymer component other than propylene in the propylene/α-olefin copolymer. However, the adhesive strength was low. Since the adhesive strength is insufficient, there is a concern that the content may leak due to delamination, making it unsuitable as a packaging material.
Comparative Example 3 contains only one type of α-olefin, which is a copolymerization component other than propylene in the propylene/α-olefin copolymer, and contains a propylene-based resin (B-3) having a large heat of fusion. The adhesion strength was low. Since the adhesive strength is insufficient, there is a concern that the content may leak due to delamination, making it unsuitable as a packaging material.

Comparative Example 4 did not contain a comonomer and contained a propylene homopolymer (B-5) having a large heat of fusion, so that the adhesive strength was low. Since the adhesive strength is insufficient, there is a concern that the content may leak due to delamination, making it unsuitable as a packaging material.

In Comparative Example 5, in which only the modified polyester elastomer (A) was used, the fluidity at the time of melting was too high, so a laminate having a uniform thickness could not be obtained by co-extrusion molding, and adhesion evaluation could not be performed. could not. That is, it was difficult to apply the modified polyester-based elastomer (A) alone to the laminate.

Comparative Example 6, in which only the propylene-based resin (B-1) was used, did not contain the modified polyester-based elastomer (A), so the adhesive strength was insufficient, and there was concern that the contents would leak due to delamination. Therefore, it is not suitable as a packaging material.

Since Comparative Example 7 contains a small amount of the modified polyester elastomer (A), the adhesion strength is insufficient, and there is a concern that the content may leak due to delamination, and is unsuitable as a packaging material.

Comparative Example 8 was satisfactory in adhesive strength, but since a tackifier with low oil resistance was blended, the amount of heptane eluted increased, and the oil resistance was poor. Unsuitable for packaging materials.

Claims (6)

A modified polyester obtained by modifying a saturated polyester thermoplastic elastomer having a polyalkylene ether glycol segment content of 58 to 73% by mass with an unsaturated carboxylic acid and/or a derivative thereof in the presence of a radical generator. A method for producing an adhesive resin composition by mixing an elastomer (A) and a propylene-based resin (B) satisfying the following conditions (Bi) and (B-ii), wherein the modified polyester-based elastomer (A) Adhesive resin in which the ratio of the modified polyester-based elastomer (A) is 25 to 65% by mass and the ratio of the propylene-based resin (B) is 35 to 75% by mass in the total 100% by mass of the propylene-based resin (B). A method of making the composition.
(Bi) The heat of fusion is in the range of 2 to 50 mJ/mg.
(B-ii) A propylene/α-olefin copolymer, wherein the α-olefin is ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-heptene, 1-hexene, 1 - at least two selected from the group consisting of octene and 1-nonene. 2. The method for producing an adhesive resin composition according to claim 1, wherein the adhesive resin composition does not contain a tackifier. Claim 1 , wherein the adhesive resin composition has an evaporation residue of 400 μg/ml or less in a heptane elution test of the evaporation residue test method of the specifications and standards for foods, additives, etc. (Ministry of Health and Welfare Notification No. 370 of 1959). 3. The method for producing an adhesive resin composition according to 2. A method for forming an adhesive layer, comprising forming an adhesive layer from an adhesive resin composition produced by the method for producing an adhesive resin composition according to any one of claims 1 to 3. A method for producing a laminate, wherein an adhesive layer is formed by the method for forming an adhesive layer according to claim 4. 6. The laminate according to claim 5, wherein the layer in contact with one surface of the adhesive layer is a styrene-based resin layer, and the layer in contact with the other surface is an ethylene-vinyl alcohol copolymer layer . manufacturing method .